xref: /PHP-5.6/ext/sqlite3/libsqlite/sqlite3.h (revision b5d1530e)
1 /*
2 ** 2001 September 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 suppose 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 ** Provide the ability to override linkage features of the interface.
47 */
48 #ifndef SQLITE_EXTERN
49 # define SQLITE_EXTERN extern
50 #endif
51 #ifndef SQLITE_API
52 # define SQLITE_API
53 #endif
54 #ifndef SQLITE_CDECL
55 # define SQLITE_CDECL
56 #endif
57 #ifndef SQLITE_STDCALL
58 # define SQLITE_STDCALL
59 #endif
60 
61 /*
62 ** These no-op macros are used in front of interfaces to mark those
63 ** interfaces as either deprecated or experimental.  New applications
64 ** should not use deprecated interfaces - they are supported for backwards
65 ** compatibility only.  Application writers should be aware that
66 ** experimental interfaces are subject to change in point releases.
67 **
68 ** These macros used to resolve to various kinds of compiler magic that
69 ** would generate warning messages when they were used.  But that
70 ** compiler magic ended up generating such a flurry of bug reports
71 ** that we have taken it all out and gone back to using simple
72 ** noop macros.
73 */
74 #define SQLITE_DEPRECATED
75 #define SQLITE_EXPERIMENTAL
76 
77 /*
78 ** Ensure these symbols were not defined by some previous header file.
79 */
80 #ifdef SQLITE_VERSION
81 # undef SQLITE_VERSION
82 #endif
83 #ifdef SQLITE_VERSION_NUMBER
84 # undef SQLITE_VERSION_NUMBER
85 #endif
86 
87 /*
88 ** CAPI3REF: Compile-Time Library Version Numbers
89 **
90 ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
91 ** evaluates to a string literal that is the SQLite version in the
92 ** format "X.Y.Z" where X is the major version number (always 3 for
93 ** SQLite3) and Y is the minor version number and Z is the release number.)^
94 ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
95 ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
96 ** numbers used in [SQLITE_VERSION].)^
97 ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
98 ** be larger than the release from which it is derived.  Either Y will
99 ** be held constant and Z will be incremented or else Y will be incremented
100 ** and Z will be reset to zero.
101 **
102 ** Since version 3.6.18, SQLite source code has been stored in the
103 ** <a href="http://www.fossil-scm.org/">Fossil configuration management
104 ** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
105 ** a string which identifies a particular check-in of SQLite
106 ** within its configuration management system.  ^The SQLITE_SOURCE_ID
107 ** string contains the date and time of the check-in (UTC) and an SHA1
108 ** hash of the entire source tree.
109 **
110 ** See also: [sqlite3_libversion()],
111 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
112 ** [sqlite_version()] and [sqlite_source_id()].
113 */
114 #define SQLITE_VERSION        "3.8.10.2"
115 #define SQLITE_VERSION_NUMBER 3008010
116 #define SQLITE_SOURCE_ID      "2015-05-20 18:17:19 2ef4f3a5b1d1d0c4338f8243d40a2452cc1f7fe4"
117 
118 /*
119 ** CAPI3REF: Run-Time Library Version Numbers
120 ** KEYWORDS: sqlite3_version, sqlite3_sourceid
121 **
122 ** These interfaces provide the same information as the [SQLITE_VERSION],
123 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
124 ** but are associated with the library instead of the header file.  ^(Cautious
125 ** programmers might include assert() statements in their application to
126 ** verify that values returned by these interfaces match the macros in
127 ** the header, and thus insure that the application is
128 ** compiled with matching library and header files.
129 **
130 ** <blockquote><pre>
131 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
132 ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
133 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
134 ** </pre></blockquote>)^
135 **
136 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
137 ** macro.  ^The sqlite3_libversion() function returns a pointer to the
138 ** to the sqlite3_version[] string constant.  The sqlite3_libversion()
139 ** function is provided for use in DLLs since DLL users usually do not have
140 ** direct access to string constants within the DLL.  ^The
141 ** sqlite3_libversion_number() function returns an integer equal to
142 ** [SQLITE_VERSION_NUMBER].  ^The sqlite3_sourceid() function returns
143 ** a pointer to a string constant whose value is the same as the
144 ** [SQLITE_SOURCE_ID] C preprocessor macro.
145 **
146 ** See also: [sqlite_version()] and [sqlite_source_id()].
147 */
148 SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
149 SQLITE_API const char *SQLITE_STDCALL sqlite3_libversion(void);
150 SQLITE_API const char *SQLITE_STDCALL sqlite3_sourceid(void);
151 SQLITE_API int SQLITE_STDCALL sqlite3_libversion_number(void);
152 
153 /*
154 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
155 **
156 ** ^The sqlite3_compileoption_used() function returns 0 or 1
157 ** indicating whether the specified option was defined at
158 ** compile time.  ^The SQLITE_ prefix may be omitted from the
159 ** option name passed to sqlite3_compileoption_used().
160 **
161 ** ^The sqlite3_compileoption_get() function allows iterating
162 ** over the list of options that were defined at compile time by
163 ** returning the N-th compile time option string.  ^If N is out of range,
164 ** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_
165 ** prefix is omitted from any strings returned by
166 ** sqlite3_compileoption_get().
167 **
168 ** ^Support for the diagnostic functions sqlite3_compileoption_used()
169 ** and sqlite3_compileoption_get() may be omitted by specifying the
170 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
171 **
172 ** See also: SQL functions [sqlite_compileoption_used()] and
173 ** [sqlite_compileoption_get()] and the [compile_options pragma].
174 */
175 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
176 SQLITE_API int SQLITE_STDCALL sqlite3_compileoption_used(const char *zOptName);
177 SQLITE_API const char *SQLITE_STDCALL sqlite3_compileoption_get(int N);
178 #endif
179 
180 /*
181 ** CAPI3REF: Test To See If The Library Is Threadsafe
182 **
183 ** ^The sqlite3_threadsafe() function returns zero if and only if
184 ** SQLite was compiled with mutexing code omitted due to the
185 ** [SQLITE_THREADSAFE] compile-time option being set to 0.
186 **
187 ** SQLite can be compiled with or without mutexes.  When
188 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
189 ** are enabled and SQLite is threadsafe.  When the
190 ** [SQLITE_THREADSAFE] macro is 0,
191 ** the mutexes are omitted.  Without the mutexes, it is not safe
192 ** to use SQLite concurrently from more than one thread.
193 **
194 ** Enabling mutexes incurs a measurable performance penalty.
195 ** So if speed is of utmost importance, it makes sense to disable
196 ** the mutexes.  But for maximum safety, mutexes should be enabled.
197 ** ^The default behavior is for mutexes to be enabled.
198 **
199 ** This interface can be used by an application to make sure that the
200 ** version of SQLite that it is linking against was compiled with
201 ** the desired setting of the [SQLITE_THREADSAFE] macro.
202 **
203 ** This interface only reports on the compile-time mutex setting
204 ** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
205 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
206 ** can be fully or partially disabled using a call to [sqlite3_config()]
207 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
208 ** or [SQLITE_CONFIG_SERIALIZED].  ^(The return value of the
209 ** sqlite3_threadsafe() function shows only the compile-time setting of
210 ** thread safety, not any run-time changes to that setting made by
211 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
212 ** is unchanged by calls to sqlite3_config().)^
213 **
214 ** See the [threading mode] documentation for additional information.
215 */
216 SQLITE_API int SQLITE_STDCALL sqlite3_threadsafe(void);
217 
218 /*
219 ** CAPI3REF: Database Connection Handle
220 ** KEYWORDS: {database connection} {database connections}
221 **
222 ** Each open SQLite database is represented by a pointer to an instance of
223 ** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
224 ** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
225 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
226 ** and [sqlite3_close_v2()] are its destructors.  There are many other
227 ** interfaces (such as
228 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
229 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
230 ** sqlite3 object.
231 */
232 typedef struct sqlite3 sqlite3;
233 
234 /*
235 ** CAPI3REF: 64-Bit Integer Types
236 ** KEYWORDS: sqlite_int64 sqlite_uint64
237 **
238 ** Because there is no cross-platform way to specify 64-bit integer types
239 ** SQLite includes typedefs for 64-bit signed and unsigned integers.
240 **
241 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
242 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
243 ** compatibility only.
244 **
245 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
246 ** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
247 ** sqlite3_uint64 and sqlite_uint64 types can store integer values
248 ** between 0 and +18446744073709551615 inclusive.
249 */
250 #ifdef SQLITE_INT64_TYPE
251   typedef SQLITE_INT64_TYPE sqlite_int64;
252   typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
253 #elif defined(_MSC_VER) || defined(__BORLANDC__)
254   typedef __int64 sqlite_int64;
255   typedef unsigned __int64 sqlite_uint64;
256 #else
257   typedef long long int sqlite_int64;
258   typedef unsigned long long int sqlite_uint64;
259 #endif
260 typedef sqlite_int64 sqlite3_int64;
261 typedef sqlite_uint64 sqlite3_uint64;
262 
263 /*
264 ** If compiling for a processor that lacks floating point support,
265 ** substitute integer for floating-point.
266 */
267 #ifdef SQLITE_OMIT_FLOATING_POINT
268 # define double sqlite3_int64
269 #endif
270 
271 /*
272 ** CAPI3REF: Closing A Database Connection
273 ** DESTRUCTOR: sqlite3
274 **
275 ** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
276 ** for the [sqlite3] object.
277 ** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
278 ** the [sqlite3] object is successfully destroyed and all associated
279 ** resources are deallocated.
280 **
281 ** ^If the database connection is associated with unfinalized prepared
282 ** statements or unfinished sqlite3_backup objects then sqlite3_close()
283 ** will leave the database connection open and return [SQLITE_BUSY].
284 ** ^If sqlite3_close_v2() is called with unfinalized prepared statements
285 ** and/or unfinished sqlite3_backups, then the database connection becomes
286 ** an unusable "zombie" which will automatically be deallocated when the
287 ** last prepared statement is finalized or the last sqlite3_backup is
288 ** finished.  The sqlite3_close_v2() interface is intended for use with
289 ** host languages that are garbage collected, and where the order in which
290 ** destructors are called is arbitrary.
291 **
292 ** Applications should [sqlite3_finalize | finalize] all [prepared statements],
293 ** [sqlite3_blob_close | close] all [BLOB handles], and
294 ** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
295 ** with the [sqlite3] object prior to attempting to close the object.  ^If
296 ** sqlite3_close_v2() is called on a [database connection] that still has
297 ** outstanding [prepared statements], [BLOB handles], and/or
298 ** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation
299 ** of resources is deferred until all [prepared statements], [BLOB handles],
300 ** and [sqlite3_backup] objects are also destroyed.
301 **
302 ** ^If an [sqlite3] object is destroyed while a transaction is open,
303 ** the transaction is automatically rolled back.
304 **
305 ** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
306 ** must be either a NULL
307 ** pointer or an [sqlite3] object pointer obtained
308 ** from [sqlite3_open()], [sqlite3_open16()], or
309 ** [sqlite3_open_v2()], and not previously closed.
310 ** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
311 ** argument is a harmless no-op.
312 */
313 SQLITE_API int SQLITE_STDCALL sqlite3_close(sqlite3*);
314 SQLITE_API int SQLITE_STDCALL sqlite3_close_v2(sqlite3*);
315 
316 /*
317 ** The type for a callback function.
318 ** This is legacy and deprecated.  It is included for historical
319 ** compatibility and is not documented.
320 */
321 typedef int (*sqlite3_callback)(void*,int,char**, char**);
322 
323 /*
324 ** CAPI3REF: One-Step Query Execution Interface
325 ** METHOD: sqlite3
326 **
327 ** The sqlite3_exec() interface is a convenience wrapper around
328 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
329 ** that allows an application to run multiple statements of SQL
330 ** without having to use a lot of C code.
331 **
332 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
333 ** semicolon-separate SQL statements passed into its 2nd argument,
334 ** in the context of the [database connection] passed in as its 1st
335 ** argument.  ^If the callback function of the 3rd argument to
336 ** sqlite3_exec() is not NULL, then it is invoked for each result row
337 ** coming out of the evaluated SQL statements.  ^The 4th argument to
338 ** sqlite3_exec() is relayed through to the 1st argument of each
339 ** callback invocation.  ^If the callback pointer to sqlite3_exec()
340 ** is NULL, then no callback is ever invoked and result rows are
341 ** ignored.
342 **
343 ** ^If an error occurs while evaluating the SQL statements passed into
344 ** sqlite3_exec(), then execution of the current statement stops and
345 ** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
346 ** is not NULL then any error message is written into memory obtained
347 ** from [sqlite3_malloc()] and passed back through the 5th parameter.
348 ** To avoid memory leaks, the application should invoke [sqlite3_free()]
349 ** on error message strings returned through the 5th parameter of
350 ** of sqlite3_exec() after the error message string is no longer needed.
351 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
352 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
353 ** NULL before returning.
354 **
355 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
356 ** routine returns SQLITE_ABORT without invoking the callback again and
357 ** without running any subsequent SQL statements.
358 **
359 ** ^The 2nd argument to the sqlite3_exec() callback function is the
360 ** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
361 ** callback is an array of pointers to strings obtained as if from
362 ** [sqlite3_column_text()], one for each column.  ^If an element of a
363 ** result row is NULL then the corresponding string pointer for the
364 ** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
365 ** sqlite3_exec() callback is an array of pointers to strings where each
366 ** entry represents the name of corresponding result column as obtained
367 ** from [sqlite3_column_name()].
368 **
369 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
370 ** to an empty string, or a pointer that contains only whitespace and/or
371 ** SQL comments, then no SQL statements are evaluated and the database
372 ** is not changed.
373 **
374 ** Restrictions:
375 **
376 ** <ul>
377 ** <li> The application must insure that the 1st parameter to sqlite3_exec()
378 **      is a valid and open [database connection].
379 ** <li> The application must not close the [database connection] specified by
380 **      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
381 ** <li> The application must not modify the SQL statement text passed into
382 **      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
383 ** </ul>
384 */
385 SQLITE_API int SQLITE_STDCALL sqlite3_exec(
386   sqlite3*,                                  /* An open database */
387   const char *sql,                           /* SQL to be evaluated */
388   int (*callback)(void*,int,char**,char**),  /* Callback function */
389   void *,                                    /* 1st argument to callback */
390   char **errmsg                              /* Error msg written here */
391 );
392 
393 /*
394 ** CAPI3REF: Result Codes
395 ** KEYWORDS: {result code definitions}
396 **
397 ** Many SQLite functions return an integer result code from the set shown
398 ** here in order to indicate success or failure.
399 **
400 ** New error codes may be added in future versions of SQLite.
401 **
402 ** See also: [extended result code definitions]
403 */
404 #define SQLITE_OK           0   /* Successful result */
405 /* beginning-of-error-codes */
406 #define SQLITE_ERROR        1   /* SQL error or missing database */
407 #define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
408 #define SQLITE_PERM         3   /* Access permission denied */
409 #define SQLITE_ABORT        4   /* Callback routine requested an abort */
410 #define SQLITE_BUSY         5   /* The database file is locked */
411 #define SQLITE_LOCKED       6   /* A table in the database is locked */
412 #define SQLITE_NOMEM        7   /* A malloc() failed */
413 #define SQLITE_READONLY     8   /* Attempt to write a readonly database */
414 #define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
415 #define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
416 #define SQLITE_CORRUPT     11   /* The database disk image is malformed */
417 #define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
418 #define SQLITE_FULL        13   /* Insertion failed because database is full */
419 #define SQLITE_CANTOPEN    14   /* Unable to open the database file */
420 #define SQLITE_PROTOCOL    15   /* Database lock protocol error */
421 #define SQLITE_EMPTY       16   /* Database is empty */
422 #define SQLITE_SCHEMA      17   /* The database schema changed */
423 #define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
424 #define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
425 #define SQLITE_MISMATCH    20   /* Data type mismatch */
426 #define SQLITE_MISUSE      21   /* Library used incorrectly */
427 #define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
428 #define SQLITE_AUTH        23   /* Authorization denied */
429 #define SQLITE_FORMAT      24   /* Auxiliary database format error */
430 #define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
431 #define SQLITE_NOTADB      26   /* File opened that is not a database file */
432 #define SQLITE_NOTICE      27   /* Notifications from sqlite3_log() */
433 #define SQLITE_WARNING     28   /* Warnings from sqlite3_log() */
434 #define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
435 #define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
436 /* end-of-error-codes */
437 
438 /*
439 ** CAPI3REF: Extended Result Codes
440 ** KEYWORDS: {extended result code definitions}
441 **
442 ** In its default configuration, SQLite API routines return one of 30 integer
443 ** [result codes].  However, experience has shown that many of
444 ** these result codes are too coarse-grained.  They do not provide as
445 ** much information about problems as programmers might like.  In an effort to
446 ** address this, newer versions of SQLite (version 3.3.8 and later) include
447 ** support for additional result codes that provide more detailed information
448 ** about errors. These [extended result codes] are enabled or disabled
449 ** on a per database connection basis using the
450 ** [sqlite3_extended_result_codes()] API.  Or, the extended code for
451 ** the most recent error can be obtained using
452 ** [sqlite3_extended_errcode()].
453 */
454 #define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
455 #define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
456 #define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
457 #define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
458 #define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
459 #define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
460 #define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
461 #define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
462 #define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
463 #define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
464 #define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
465 #define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
466 #define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
467 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
468 #define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
469 #define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
470 #define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
471 #define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
472 #define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
473 #define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
474 #define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
475 #define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
476 #define SQLITE_IOERR_DELETE_NOENT      (SQLITE_IOERR | (23<<8))
477 #define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
478 #define SQLITE_IOERR_GETTEMPPATH       (SQLITE_IOERR | (25<<8))
479 #define SQLITE_IOERR_CONVPATH          (SQLITE_IOERR | (26<<8))
480 #define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
481 #define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
482 #define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
483 #define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
484 #define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
485 #define SQLITE_CANTOPEN_FULLPATH       (SQLITE_CANTOPEN | (3<<8))
486 #define SQLITE_CANTOPEN_CONVPATH       (SQLITE_CANTOPEN | (4<<8))
487 #define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
488 #define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
489 #define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
490 #define SQLITE_READONLY_ROLLBACK       (SQLITE_READONLY | (3<<8))
491 #define SQLITE_READONLY_DBMOVED        (SQLITE_READONLY | (4<<8))
492 #define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
493 #define SQLITE_CONSTRAINT_CHECK        (SQLITE_CONSTRAINT | (1<<8))
494 #define SQLITE_CONSTRAINT_COMMITHOOK   (SQLITE_CONSTRAINT | (2<<8))
495 #define SQLITE_CONSTRAINT_FOREIGNKEY   (SQLITE_CONSTRAINT | (3<<8))
496 #define SQLITE_CONSTRAINT_FUNCTION     (SQLITE_CONSTRAINT | (4<<8))
497 #define SQLITE_CONSTRAINT_NOTNULL      (SQLITE_CONSTRAINT | (5<<8))
498 #define SQLITE_CONSTRAINT_PRIMARYKEY   (SQLITE_CONSTRAINT | (6<<8))
499 #define SQLITE_CONSTRAINT_TRIGGER      (SQLITE_CONSTRAINT | (7<<8))
500 #define SQLITE_CONSTRAINT_UNIQUE       (SQLITE_CONSTRAINT | (8<<8))
501 #define SQLITE_CONSTRAINT_VTAB         (SQLITE_CONSTRAINT | (9<<8))
502 #define SQLITE_CONSTRAINT_ROWID        (SQLITE_CONSTRAINT |(10<<8))
503 #define SQLITE_NOTICE_RECOVER_WAL      (SQLITE_NOTICE | (1<<8))
504 #define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
505 #define SQLITE_WARNING_AUTOINDEX       (SQLITE_WARNING | (1<<8))
506 #define SQLITE_AUTH_USER               (SQLITE_AUTH | (1<<8))
507 
508 /*
509 ** CAPI3REF: Flags For File Open Operations
510 **
511 ** These bit values are intended for use in the
512 ** 3rd parameter to the [sqlite3_open_v2()] interface and
513 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
514 */
515 #define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
516 #define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
517 #define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
518 #define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
519 #define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
520 #define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
521 #define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
522 #define SQLITE_OPEN_MEMORY           0x00000080  /* Ok for sqlite3_open_v2() */
523 #define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
524 #define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
525 #define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
526 #define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
527 #define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
528 #define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
529 #define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
530 #define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
531 #define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
532 #define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
533 #define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
534 #define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
535 
536 /* Reserved:                         0x00F00000 */
537 
538 /*
539 ** CAPI3REF: Device Characteristics
540 **
541 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
542 ** object returns an integer which is a vector of these
543 ** bit values expressing I/O characteristics of the mass storage
544 ** device that holds the file that the [sqlite3_io_methods]
545 ** refers to.
546 **
547 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
548 ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
549 ** mean that writes of blocks that are nnn bytes in size and
550 ** are aligned to an address which is an integer multiple of
551 ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
552 ** that when data is appended to a file, the data is appended
553 ** first then the size of the file is extended, never the other
554 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
555 ** information is written to disk in the same order as calls
556 ** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
557 ** after reboot following a crash or power loss, the only bytes in a
558 ** file that were written at the application level might have changed
559 ** and that adjacent bytes, even bytes within the same sector are
560 ** guaranteed to be unchanged.  The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
561 ** flag indicate that a file cannot be deleted when open.  The
562 ** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
563 ** read-only media and cannot be changed even by processes with
564 ** elevated privileges.
565 */
566 #define SQLITE_IOCAP_ATOMIC                 0x00000001
567 #define SQLITE_IOCAP_ATOMIC512              0x00000002
568 #define SQLITE_IOCAP_ATOMIC1K               0x00000004
569 #define SQLITE_IOCAP_ATOMIC2K               0x00000008
570 #define SQLITE_IOCAP_ATOMIC4K               0x00000010
571 #define SQLITE_IOCAP_ATOMIC8K               0x00000020
572 #define SQLITE_IOCAP_ATOMIC16K              0x00000040
573 #define SQLITE_IOCAP_ATOMIC32K              0x00000080
574 #define SQLITE_IOCAP_ATOMIC64K              0x00000100
575 #define SQLITE_IOCAP_SAFE_APPEND            0x00000200
576 #define SQLITE_IOCAP_SEQUENTIAL             0x00000400
577 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
578 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000
579 #define SQLITE_IOCAP_IMMUTABLE              0x00002000
580 
581 /*
582 ** CAPI3REF: File Locking Levels
583 **
584 ** SQLite uses one of these integer values as the second
585 ** argument to calls it makes to the xLock() and xUnlock() methods
586 ** of an [sqlite3_io_methods] object.
587 */
588 #define SQLITE_LOCK_NONE          0
589 #define SQLITE_LOCK_SHARED        1
590 #define SQLITE_LOCK_RESERVED      2
591 #define SQLITE_LOCK_PENDING       3
592 #define SQLITE_LOCK_EXCLUSIVE     4
593 
594 /*
595 ** CAPI3REF: Synchronization Type Flags
596 **
597 ** When SQLite invokes the xSync() method of an
598 ** [sqlite3_io_methods] object it uses a combination of
599 ** these integer values as the second argument.
600 **
601 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
602 ** sync operation only needs to flush data to mass storage.  Inode
603 ** information need not be flushed. If the lower four bits of the flag
604 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
605 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
606 ** to use Mac OS X style fullsync instead of fsync().
607 **
608 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
609 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
610 ** settings.  The [synchronous pragma] determines when calls to the
611 ** xSync VFS method occur and applies uniformly across all platforms.
612 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
613 ** energetic or rigorous or forceful the sync operations are and
614 ** only make a difference on Mac OSX for the default SQLite code.
615 ** (Third-party VFS implementations might also make the distinction
616 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
617 ** operating systems natively supported by SQLite, only Mac OSX
618 ** cares about the difference.)
619 */
620 #define SQLITE_SYNC_NORMAL        0x00002
621 #define SQLITE_SYNC_FULL          0x00003
622 #define SQLITE_SYNC_DATAONLY      0x00010
623 
624 /*
625 ** CAPI3REF: OS Interface Open File Handle
626 **
627 ** An [sqlite3_file] object represents an open file in the
628 ** [sqlite3_vfs | OS interface layer].  Individual OS interface
629 ** implementations will
630 ** want to subclass this object by appending additional fields
631 ** for their own use.  The pMethods entry is a pointer to an
632 ** [sqlite3_io_methods] object that defines methods for performing
633 ** I/O operations on the open file.
634 */
635 typedef struct sqlite3_file sqlite3_file;
636 struct sqlite3_file {
637   const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
638 };
639 
640 /*
641 ** CAPI3REF: OS Interface File Virtual Methods Object
642 **
643 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
644 ** [sqlite3_file] object (or, more commonly, a subclass of the
645 ** [sqlite3_file] object) with a pointer to an instance of this object.
646 ** This object defines the methods used to perform various operations
647 ** against the open file represented by the [sqlite3_file] object.
648 **
649 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
650 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
651 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
652 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
653 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
654 ** to NULL.
655 **
656 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
657 ** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
658 ** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
659 ** flag may be ORed in to indicate that only the data of the file
660 ** and not its inode needs to be synced.
661 **
662 ** The integer values to xLock() and xUnlock() are one of
663 ** <ul>
664 ** <li> [SQLITE_LOCK_NONE],
665 ** <li> [SQLITE_LOCK_SHARED],
666 ** <li> [SQLITE_LOCK_RESERVED],
667 ** <li> [SQLITE_LOCK_PENDING], or
668 ** <li> [SQLITE_LOCK_EXCLUSIVE].
669 ** </ul>
670 ** xLock() increases the lock. xUnlock() decreases the lock.
671 ** The xCheckReservedLock() method checks whether any database connection,
672 ** either in this process or in some other process, is holding a RESERVED,
673 ** PENDING, or EXCLUSIVE lock on the file.  It returns true
674 ** if such a lock exists and false otherwise.
675 **
676 ** The xFileControl() method is a generic interface that allows custom
677 ** VFS implementations to directly control an open file using the
678 ** [sqlite3_file_control()] interface.  The second "op" argument is an
679 ** integer opcode.  The third argument is a generic pointer intended to
680 ** point to a structure that may contain arguments or space in which to
681 ** write return values.  Potential uses for xFileControl() might be
682 ** functions to enable blocking locks with timeouts, to change the
683 ** locking strategy (for example to use dot-file locks), to inquire
684 ** about the status of a lock, or to break stale locks.  The SQLite
685 ** core reserves all opcodes less than 100 for its own use.
686 ** A [file control opcodes | list of opcodes] less than 100 is available.
687 ** Applications that define a custom xFileControl method should use opcodes
688 ** greater than 100 to avoid conflicts.  VFS implementations should
689 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
690 ** recognize.
691 **
692 ** The xSectorSize() method returns the sector size of the
693 ** device that underlies the file.  The sector size is the
694 ** minimum write that can be performed without disturbing
695 ** other bytes in the file.  The xDeviceCharacteristics()
696 ** method returns a bit vector describing behaviors of the
697 ** underlying device:
698 **
699 ** <ul>
700 ** <li> [SQLITE_IOCAP_ATOMIC]
701 ** <li> [SQLITE_IOCAP_ATOMIC512]
702 ** <li> [SQLITE_IOCAP_ATOMIC1K]
703 ** <li> [SQLITE_IOCAP_ATOMIC2K]
704 ** <li> [SQLITE_IOCAP_ATOMIC4K]
705 ** <li> [SQLITE_IOCAP_ATOMIC8K]
706 ** <li> [SQLITE_IOCAP_ATOMIC16K]
707 ** <li> [SQLITE_IOCAP_ATOMIC32K]
708 ** <li> [SQLITE_IOCAP_ATOMIC64K]
709 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
710 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
711 ** </ul>
712 **
713 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
714 ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
715 ** mean that writes of blocks that are nnn bytes in size and
716 ** are aligned to an address which is an integer multiple of
717 ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
718 ** that when data is appended to a file, the data is appended
719 ** first then the size of the file is extended, never the other
720 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
721 ** information is written to disk in the same order as calls
722 ** to xWrite().
723 **
724 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
725 ** in the unread portions of the buffer with zeros.  A VFS that
726 ** fails to zero-fill short reads might seem to work.  However,
727 ** failure to zero-fill short reads will eventually lead to
728 ** database corruption.
729 */
730 typedef struct sqlite3_io_methods sqlite3_io_methods;
731 struct sqlite3_io_methods {
732   int iVersion;
733   int (*xClose)(sqlite3_file*);
734   int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
735   int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
736   int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
737   int (*xSync)(sqlite3_file*, int flags);
738   int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
739   int (*xLock)(sqlite3_file*, int);
740   int (*xUnlock)(sqlite3_file*, int);
741   int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
742   int (*xFileControl)(sqlite3_file*, int op, void *pArg);
743   int (*xSectorSize)(sqlite3_file*);
744   int (*xDeviceCharacteristics)(sqlite3_file*);
745   /* Methods above are valid for version 1 */
746   int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
747   int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
748   void (*xShmBarrier)(sqlite3_file*);
749   int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
750   /* Methods above are valid for version 2 */
751   int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
752   int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
753   /* Methods above are valid for version 3 */
754   /* Additional methods may be added in future releases */
755 };
756 
757 /*
758 ** CAPI3REF: Standard File Control Opcodes
759 ** KEYWORDS: {file control opcodes} {file control opcode}
760 **
761 ** These integer constants are opcodes for the xFileControl method
762 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
763 ** interface.
764 **
765 ** <ul>
766 ** <li>[[SQLITE_FCNTL_LOCKSTATE]]
767 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
768 ** opcode causes the xFileControl method to write the current state of
769 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
770 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
771 ** into an integer that the pArg argument points to. This capability
772 ** is used during testing and is only available when the SQLITE_TEST
773 ** compile-time option is used.
774 **
775 ** <li>[[SQLITE_FCNTL_SIZE_HINT]]
776 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
777 ** layer a hint of how large the database file will grow to be during the
778 ** current transaction.  This hint is not guaranteed to be accurate but it
779 ** is often close.  The underlying VFS might choose to preallocate database
780 ** file space based on this hint in order to help writes to the database
781 ** file run faster.
782 **
783 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
784 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
785 ** extends and truncates the database file in chunks of a size specified
786 ** by the user. The fourth argument to [sqlite3_file_control()] should
787 ** point to an integer (type int) containing the new chunk-size to use
788 ** for the nominated database. Allocating database file space in large
789 ** chunks (say 1MB at a time), may reduce file-system fragmentation and
790 ** improve performance on some systems.
791 **
792 ** <li>[[SQLITE_FCNTL_FILE_POINTER]]
793 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
794 ** to the [sqlite3_file] object associated with a particular database
795 ** connection.  See the [sqlite3_file_control()] documentation for
796 ** additional information.
797 **
798 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
799 ** No longer in use.
800 **
801 ** <li>[[SQLITE_FCNTL_SYNC]]
802 ** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
803 ** sent to the VFS immediately before the xSync method is invoked on a
804 ** database file descriptor. Or, if the xSync method is not invoked
805 ** because the user has configured SQLite with
806 ** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
807 ** of the xSync method. In most cases, the pointer argument passed with
808 ** this file-control is NULL. However, if the database file is being synced
809 ** as part of a multi-database commit, the argument points to a nul-terminated
810 ** string containing the transactions master-journal file name. VFSes that
811 ** do not need this signal should silently ignore this opcode. Applications
812 ** should not call [sqlite3_file_control()] with this opcode as doing so may
813 ** disrupt the operation of the specialized VFSes that do require it.
814 **
815 ** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
816 ** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
817 ** and sent to the VFS after a transaction has been committed immediately
818 ** but before the database is unlocked. VFSes that do not need this signal
819 ** should silently ignore this opcode. Applications should not call
820 ** [sqlite3_file_control()] with this opcode as doing so may disrupt the
821 ** operation of the specialized VFSes that do require it.
822 **
823 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
824 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
825 ** retry counts and intervals for certain disk I/O operations for the
826 ** windows [VFS] in order to provide robustness in the presence of
827 ** anti-virus programs.  By default, the windows VFS will retry file read,
828 ** file write, and file delete operations up to 10 times, with a delay
829 ** of 25 milliseconds before the first retry and with the delay increasing
830 ** by an additional 25 milliseconds with each subsequent retry.  This
831 ** opcode allows these two values (10 retries and 25 milliseconds of delay)
832 ** to be adjusted.  The values are changed for all database connections
833 ** within the same process.  The argument is a pointer to an array of two
834 ** integers where the first integer i the new retry count and the second
835 ** integer is the delay.  If either integer is negative, then the setting
836 ** is not changed but instead the prior value of that setting is written
837 ** into the array entry, allowing the current retry settings to be
838 ** interrogated.  The zDbName parameter is ignored.
839 **
840 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
841 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
842 ** persistent [WAL | Write Ahead Log] setting.  By default, the auxiliary
843 ** write ahead log and shared memory files used for transaction control
844 ** are automatically deleted when the latest connection to the database
845 ** closes.  Setting persistent WAL mode causes those files to persist after
846 ** close.  Persisting the files is useful when other processes that do not
847 ** have write permission on the directory containing the database file want
848 ** to read the database file, as the WAL and shared memory files must exist
849 ** in order for the database to be readable.  The fourth parameter to
850 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
851 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
852 ** WAL mode.  If the integer is -1, then it is overwritten with the current
853 ** WAL persistence setting.
854 **
855 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
856 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
857 ** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
858 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
859 ** xDeviceCharacteristics methods. The fourth parameter to
860 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
861 ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
862 ** mode.  If the integer is -1, then it is overwritten with the current
863 ** zero-damage mode setting.
864 **
865 ** <li>[[SQLITE_FCNTL_OVERWRITE]]
866 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
867 ** a write transaction to indicate that, unless it is rolled back for some
868 ** reason, the entire database file will be overwritten by the current
869 ** transaction. This is used by VACUUM operations.
870 **
871 ** <li>[[SQLITE_FCNTL_VFSNAME]]
872 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
873 ** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
874 ** final bottom-level VFS are written into memory obtained from
875 ** [sqlite3_malloc()] and the result is stored in the char* variable
876 ** that the fourth parameter of [sqlite3_file_control()] points to.
877 ** The caller is responsible for freeing the memory when done.  As with
878 ** all file-control actions, there is no guarantee that this will actually
879 ** do anything.  Callers should initialize the char* variable to a NULL
880 ** pointer in case this file-control is not implemented.  This file-control
881 ** is intended for diagnostic use only.
882 **
883 ** <li>[[SQLITE_FCNTL_PRAGMA]]
884 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
885 ** file control is sent to the open [sqlite3_file] object corresponding
886 ** to the database file to which the pragma statement refers. ^The argument
887 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
888 ** pointers to strings (char**) in which the second element of the array
889 ** is the name of the pragma and the third element is the argument to the
890 ** pragma or NULL if the pragma has no argument.  ^The handler for an
891 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
892 ** of the char** argument point to a string obtained from [sqlite3_mprintf()]
893 ** or the equivalent and that string will become the result of the pragma or
894 ** the error message if the pragma fails. ^If the
895 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
896 ** [PRAGMA] processing continues.  ^If the [SQLITE_FCNTL_PRAGMA]
897 ** file control returns [SQLITE_OK], then the parser assumes that the
898 ** VFS has handled the PRAGMA itself and the parser generates a no-op
899 ** prepared statement if result string is NULL, or that returns a copy
900 ** of the result string if the string is non-NULL.
901 ** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
902 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
903 ** that the VFS encountered an error while handling the [PRAGMA] and the
904 ** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
905 ** file control occurs at the beginning of pragma statement analysis and so
906 ** it is able to override built-in [PRAGMA] statements.
907 **
908 ** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
909 ** ^The [SQLITE_FCNTL_BUSYHANDLER]
910 ** file-control may be invoked by SQLite on the database file handle
911 ** shortly after it is opened in order to provide a custom VFS with access
912 ** to the connections busy-handler callback. The argument is of type (void **)
913 ** - an array of two (void *) values. The first (void *) actually points
914 ** to a function of type (int (*)(void *)). In order to invoke the connections
915 ** busy-handler, this function should be invoked with the second (void *) in
916 ** the array as the only argument. If it returns non-zero, then the operation
917 ** should be retried. If it returns zero, the custom VFS should abandon the
918 ** current operation.
919 **
920 ** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
921 ** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
922 ** to have SQLite generate a
923 ** temporary filename using the same algorithm that is followed to generate
924 ** temporary filenames for TEMP tables and other internal uses.  The
925 ** argument should be a char** which will be filled with the filename
926 ** written into memory obtained from [sqlite3_malloc()].  The caller should
927 ** invoke [sqlite3_free()] on the result to avoid a memory leak.
928 **
929 ** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
930 ** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
931 ** maximum number of bytes that will be used for memory-mapped I/O.
932 ** The argument is a pointer to a value of type sqlite3_int64 that
933 ** is an advisory maximum number of bytes in the file to memory map.  The
934 ** pointer is overwritten with the old value.  The limit is not changed if
935 ** the value originally pointed to is negative, and so the current limit
936 ** can be queried by passing in a pointer to a negative number.  This
937 ** file-control is used internally to implement [PRAGMA mmap_size].
938 **
939 ** <li>[[SQLITE_FCNTL_TRACE]]
940 ** The [SQLITE_FCNTL_TRACE] file control provides advisory information
941 ** to the VFS about what the higher layers of the SQLite stack are doing.
942 ** This file control is used by some VFS activity tracing [shims].
943 ** The argument is a zero-terminated string.  Higher layers in the
944 ** SQLite stack may generate instances of this file control if
945 ** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
946 **
947 ** <li>[[SQLITE_FCNTL_HAS_MOVED]]
948 ** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
949 ** pointer to an integer and it writes a boolean into that integer depending
950 ** on whether or not the file has been renamed, moved, or deleted since it
951 ** was first opened.
952 **
953 ** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
954 ** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging.  This
955 ** opcode causes the xFileControl method to swap the file handle with the one
956 ** pointed to by the pArg argument.  This capability is used during testing
957 ** and only needs to be supported when SQLITE_TEST is defined.
958 **
959 ** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
960 ** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
961 ** be advantageous to block on the next WAL lock if the lock is not immediately
962 ** available.  The WAL subsystem issues this signal during rare
963 ** circumstances in order to fix a problem with priority inversion.
964 ** Applications should <em>not</em> use this file-control.
965 **
966 ** </ul>
967 */
968 #define SQLITE_FCNTL_LOCKSTATE               1
969 #define SQLITE_FCNTL_GET_LOCKPROXYFILE       2
970 #define SQLITE_FCNTL_SET_LOCKPROXYFILE       3
971 #define SQLITE_FCNTL_LAST_ERRNO              4
972 #define SQLITE_FCNTL_SIZE_HINT               5
973 #define SQLITE_FCNTL_CHUNK_SIZE              6
974 #define SQLITE_FCNTL_FILE_POINTER            7
975 #define SQLITE_FCNTL_SYNC_OMITTED            8
976 #define SQLITE_FCNTL_WIN32_AV_RETRY          9
977 #define SQLITE_FCNTL_PERSIST_WAL            10
978 #define SQLITE_FCNTL_OVERWRITE              11
979 #define SQLITE_FCNTL_VFSNAME                12
980 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13
981 #define SQLITE_FCNTL_PRAGMA                 14
982 #define SQLITE_FCNTL_BUSYHANDLER            15
983 #define SQLITE_FCNTL_TEMPFILENAME           16
984 #define SQLITE_FCNTL_MMAP_SIZE              18
985 #define SQLITE_FCNTL_TRACE                  19
986 #define SQLITE_FCNTL_HAS_MOVED              20
987 #define SQLITE_FCNTL_SYNC                   21
988 #define SQLITE_FCNTL_COMMIT_PHASETWO        22
989 #define SQLITE_FCNTL_WIN32_SET_HANDLE       23
990 #define SQLITE_FCNTL_WAL_BLOCK              24
991 
992 /* deprecated names */
993 #define SQLITE_GET_LOCKPROXYFILE      SQLITE_FCNTL_GET_LOCKPROXYFILE
994 #define SQLITE_SET_LOCKPROXYFILE      SQLITE_FCNTL_SET_LOCKPROXYFILE
995 #define SQLITE_LAST_ERRNO             SQLITE_FCNTL_LAST_ERRNO
996 
997 
998 /*
999 ** CAPI3REF: Mutex Handle
1000 **
1001 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
1002 ** abstract type for a mutex object.  The SQLite core never looks
1003 ** at the internal representation of an [sqlite3_mutex].  It only
1004 ** deals with pointers to the [sqlite3_mutex] object.
1005 **
1006 ** Mutexes are created using [sqlite3_mutex_alloc()].
1007 */
1008 typedef struct sqlite3_mutex sqlite3_mutex;
1009 
1010 /*
1011 ** CAPI3REF: OS Interface Object
1012 **
1013 ** An instance of the sqlite3_vfs object defines the interface between
1014 ** the SQLite core and the underlying operating system.  The "vfs"
1015 ** in the name of the object stands for "virtual file system".  See
1016 ** the [VFS | VFS documentation] for further information.
1017 **
1018 ** The value of the iVersion field is initially 1 but may be larger in
1019 ** future versions of SQLite.  Additional fields may be appended to this
1020 ** object when the iVersion value is increased.  Note that the structure
1021 ** of the sqlite3_vfs object changes in the transaction between
1022 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
1023 ** modified.
1024 **
1025 ** The szOsFile field is the size of the subclassed [sqlite3_file]
1026 ** structure used by this VFS.  mxPathname is the maximum length of
1027 ** a pathname in this VFS.
1028 **
1029 ** Registered sqlite3_vfs objects are kept on a linked list formed by
1030 ** the pNext pointer.  The [sqlite3_vfs_register()]
1031 ** and [sqlite3_vfs_unregister()] interfaces manage this list
1032 ** in a thread-safe way.  The [sqlite3_vfs_find()] interface
1033 ** searches the list.  Neither the application code nor the VFS
1034 ** implementation should use the pNext pointer.
1035 **
1036 ** The pNext field is the only field in the sqlite3_vfs
1037 ** structure that SQLite will ever modify.  SQLite will only access
1038 ** or modify this field while holding a particular static mutex.
1039 ** The application should never modify anything within the sqlite3_vfs
1040 ** object once the object has been registered.
1041 **
1042 ** The zName field holds the name of the VFS module.  The name must
1043 ** be unique across all VFS modules.
1044 **
1045 ** [[sqlite3_vfs.xOpen]]
1046 ** ^SQLite guarantees that the zFilename parameter to xOpen
1047 ** is either a NULL pointer or string obtained
1048 ** from xFullPathname() with an optional suffix added.
1049 ** ^If a suffix is added to the zFilename parameter, it will
1050 ** consist of a single "-" character followed by no more than
1051 ** 11 alphanumeric and/or "-" characters.
1052 ** ^SQLite further guarantees that
1053 ** the string will be valid and unchanged until xClose() is
1054 ** called. Because of the previous sentence,
1055 ** the [sqlite3_file] can safely store a pointer to the
1056 ** filename if it needs to remember the filename for some reason.
1057 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
1058 ** must invent its own temporary name for the file.  ^Whenever the
1059 ** xFilename parameter is NULL it will also be the case that the
1060 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
1061 **
1062 ** The flags argument to xOpen() includes all bits set in
1063 ** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
1064 ** or [sqlite3_open16()] is used, then flags includes at least
1065 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
1066 ** If xOpen() opens a file read-only then it sets *pOutFlags to
1067 ** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
1068 **
1069 ** ^(SQLite will also add one of the following flags to the xOpen()
1070 ** call, depending on the object being opened:
1071 **
1072 ** <ul>
1073 ** <li>  [SQLITE_OPEN_MAIN_DB]
1074 ** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
1075 ** <li>  [SQLITE_OPEN_TEMP_DB]
1076 ** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
1077 ** <li>  [SQLITE_OPEN_TRANSIENT_DB]
1078 ** <li>  [SQLITE_OPEN_SUBJOURNAL]
1079 ** <li>  [SQLITE_OPEN_MASTER_JOURNAL]
1080 ** <li>  [SQLITE_OPEN_WAL]
1081 ** </ul>)^
1082 **
1083 ** The file I/O implementation can use the object type flags to
1084 ** change the way it deals with files.  For example, an application
1085 ** that does not care about crash recovery or rollback might make
1086 ** the open of a journal file a no-op.  Writes to this journal would
1087 ** also be no-ops, and any attempt to read the journal would return
1088 ** SQLITE_IOERR.  Or the implementation might recognize that a database
1089 ** file will be doing page-aligned sector reads and writes in a random
1090 ** order and set up its I/O subsystem accordingly.
1091 **
1092 ** SQLite might also add one of the following flags to the xOpen method:
1093 **
1094 ** <ul>
1095 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
1096 ** <li> [SQLITE_OPEN_EXCLUSIVE]
1097 ** </ul>
1098 **
1099 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
1100 ** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
1101 ** will be set for TEMP databases and their journals, transient
1102 ** databases, and subjournals.
1103 **
1104 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
1105 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
1106 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
1107 ** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
1108 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
1109 ** be created, and that it is an error if it already exists.
1110 ** It is <i>not</i> used to indicate the file should be opened
1111 ** for exclusive access.
1112 **
1113 ** ^At least szOsFile bytes of memory are allocated by SQLite
1114 ** to hold the  [sqlite3_file] structure passed as the third
1115 ** argument to xOpen.  The xOpen method does not have to
1116 ** allocate the structure; it should just fill it in.  Note that
1117 ** the xOpen method must set the sqlite3_file.pMethods to either
1118 ** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
1119 ** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
1120 ** element will be valid after xOpen returns regardless of the success
1121 ** or failure of the xOpen call.
1122 **
1123 ** [[sqlite3_vfs.xAccess]]
1124 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
1125 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
1126 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
1127 ** to test whether a file is at least readable.   The file can be a
1128 ** directory.
1129 **
1130 ** ^SQLite will always allocate at least mxPathname+1 bytes for the
1131 ** output buffer xFullPathname.  The exact size of the output buffer
1132 ** is also passed as a parameter to both  methods. If the output buffer
1133 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
1134 ** handled as a fatal error by SQLite, vfs implementations should endeavor
1135 ** to prevent this by setting mxPathname to a sufficiently large value.
1136 **
1137 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
1138 ** interfaces are not strictly a part of the filesystem, but they are
1139 ** included in the VFS structure for completeness.
1140 ** The xRandomness() function attempts to return nBytes bytes
1141 ** of good-quality randomness into zOut.  The return value is
1142 ** the actual number of bytes of randomness obtained.
1143 ** The xSleep() method causes the calling thread to sleep for at
1144 ** least the number of microseconds given.  ^The xCurrentTime()
1145 ** method returns a Julian Day Number for the current date and time as
1146 ** a floating point value.
1147 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
1148 ** Day Number multiplied by 86400000 (the number of milliseconds in
1149 ** a 24-hour day).
1150 ** ^SQLite will use the xCurrentTimeInt64() method to get the current
1151 ** date and time if that method is available (if iVersion is 2 or
1152 ** greater and the function pointer is not NULL) and will fall back
1153 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
1154 **
1155 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
1156 ** are not used by the SQLite core.  These optional interfaces are provided
1157 ** by some VFSes to facilitate testing of the VFS code. By overriding
1158 ** system calls with functions under its control, a test program can
1159 ** simulate faults and error conditions that would otherwise be difficult
1160 ** or impossible to induce.  The set of system calls that can be overridden
1161 ** varies from one VFS to another, and from one version of the same VFS to the
1162 ** next.  Applications that use these interfaces must be prepared for any
1163 ** or all of these interfaces to be NULL or for their behavior to change
1164 ** from one release to the next.  Applications must not attempt to access
1165 ** any of these methods if the iVersion of the VFS is less than 3.
1166 */
1167 typedef struct sqlite3_vfs sqlite3_vfs;
1168 typedef void (*sqlite3_syscall_ptr)(void);
1169 struct sqlite3_vfs {
1170   int iVersion;            /* Structure version number (currently 3) */
1171   int szOsFile;            /* Size of subclassed sqlite3_file */
1172   int mxPathname;          /* Maximum file pathname length */
1173   sqlite3_vfs *pNext;      /* Next registered VFS */
1174   const char *zName;       /* Name of this virtual file system */
1175   void *pAppData;          /* Pointer to application-specific data */
1176   int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
1177                int flags, int *pOutFlags);
1178   int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
1179   int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
1180   int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
1181   void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
1182   void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
1183   void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
1184   void (*xDlClose)(sqlite3_vfs*, void*);
1185   int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
1186   int (*xSleep)(sqlite3_vfs*, int microseconds);
1187   int (*xCurrentTime)(sqlite3_vfs*, double*);
1188   int (*xGetLastError)(sqlite3_vfs*, int, char *);
1189   /*
1190   ** The methods above are in version 1 of the sqlite_vfs object
1191   ** definition.  Those that follow are added in version 2 or later
1192   */
1193   int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
1194   /*
1195   ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
1196   ** Those below are for version 3 and greater.
1197   */
1198   int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
1199   sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
1200   const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
1201   /*
1202   ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
1203   ** New fields may be appended in figure versions.  The iVersion
1204   ** value will increment whenever this happens.
1205   */
1206 };
1207 
1208 /*
1209 ** CAPI3REF: Flags for the xAccess VFS method
1210 **
1211 ** These integer constants can be used as the third parameter to
1212 ** the xAccess method of an [sqlite3_vfs] object.  They determine
1213 ** what kind of permissions the xAccess method is looking for.
1214 ** With SQLITE_ACCESS_EXISTS, the xAccess method
1215 ** simply checks whether the file exists.
1216 ** With SQLITE_ACCESS_READWRITE, the xAccess method
1217 ** checks whether the named directory is both readable and writable
1218 ** (in other words, if files can be added, removed, and renamed within
1219 ** the directory).
1220 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
1221 ** [temp_store_directory pragma], though this could change in a future
1222 ** release of SQLite.
1223 ** With SQLITE_ACCESS_READ, the xAccess method
1224 ** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
1225 ** currently unused, though it might be used in a future release of
1226 ** SQLite.
1227 */
1228 #define SQLITE_ACCESS_EXISTS    0
1229 #define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
1230 #define SQLITE_ACCESS_READ      2   /* Unused */
1231 
1232 /*
1233 ** CAPI3REF: Flags for the xShmLock VFS method
1234 **
1235 ** These integer constants define the various locking operations
1236 ** allowed by the xShmLock method of [sqlite3_io_methods].  The
1237 ** following are the only legal combinations of flags to the
1238 ** xShmLock method:
1239 **
1240 ** <ul>
1241 ** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
1242 ** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
1243 ** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
1244 ** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
1245 ** </ul>
1246 **
1247 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
1248 ** was given on the corresponding lock.
1249 **
1250 ** The xShmLock method can transition between unlocked and SHARED or
1251 ** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
1252 ** and EXCLUSIVE.
1253 */
1254 #define SQLITE_SHM_UNLOCK       1
1255 #define SQLITE_SHM_LOCK         2
1256 #define SQLITE_SHM_SHARED       4
1257 #define SQLITE_SHM_EXCLUSIVE    8
1258 
1259 /*
1260 ** CAPI3REF: Maximum xShmLock index
1261 **
1262 ** The xShmLock method on [sqlite3_io_methods] may use values
1263 ** between 0 and this upper bound as its "offset" argument.
1264 ** The SQLite core will never attempt to acquire or release a
1265 ** lock outside of this range
1266 */
1267 #define SQLITE_SHM_NLOCK        8
1268 
1269 
1270 /*
1271 ** CAPI3REF: Initialize The SQLite Library
1272 **
1273 ** ^The sqlite3_initialize() routine initializes the
1274 ** SQLite library.  ^The sqlite3_shutdown() routine
1275 ** deallocates any resources that were allocated by sqlite3_initialize().
1276 ** These routines are designed to aid in process initialization and
1277 ** shutdown on embedded systems.  Workstation applications using
1278 ** SQLite normally do not need to invoke either of these routines.
1279 **
1280 ** A call to sqlite3_initialize() is an "effective" call if it is
1281 ** the first time sqlite3_initialize() is invoked during the lifetime of
1282 ** the process, or if it is the first time sqlite3_initialize() is invoked
1283 ** following a call to sqlite3_shutdown().  ^(Only an effective call
1284 ** of sqlite3_initialize() does any initialization.  All other calls
1285 ** are harmless no-ops.)^
1286 **
1287 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
1288 ** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
1289 ** an effective call to sqlite3_shutdown() does any deinitialization.
1290 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
1291 **
1292 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
1293 ** is not.  The sqlite3_shutdown() interface must only be called from a
1294 ** single thread.  All open [database connections] must be closed and all
1295 ** other SQLite resources must be deallocated prior to invoking
1296 ** sqlite3_shutdown().
1297 **
1298 ** Among other things, ^sqlite3_initialize() will invoke
1299 ** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
1300 ** will invoke sqlite3_os_end().
1301 **
1302 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
1303 ** ^If for some reason, sqlite3_initialize() is unable to initialize
1304 ** the library (perhaps it is unable to allocate a needed resource such
1305 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
1306 **
1307 ** ^The sqlite3_initialize() routine is called internally by many other
1308 ** SQLite interfaces so that an application usually does not need to
1309 ** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
1310 ** calls sqlite3_initialize() so the SQLite library will be automatically
1311 ** initialized when [sqlite3_open()] is called if it has not be initialized
1312 ** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
1313 ** compile-time option, then the automatic calls to sqlite3_initialize()
1314 ** are omitted and the application must call sqlite3_initialize() directly
1315 ** prior to using any other SQLite interface.  For maximum portability,
1316 ** it is recommended that applications always invoke sqlite3_initialize()
1317 ** directly prior to using any other SQLite interface.  Future releases
1318 ** of SQLite may require this.  In other words, the behavior exhibited
1319 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
1320 ** default behavior in some future release of SQLite.
1321 **
1322 ** The sqlite3_os_init() routine does operating-system specific
1323 ** initialization of the SQLite library.  The sqlite3_os_end()
1324 ** routine undoes the effect of sqlite3_os_init().  Typical tasks
1325 ** performed by these routines include allocation or deallocation
1326 ** of static resources, initialization of global variables,
1327 ** setting up a default [sqlite3_vfs] module, or setting up
1328 ** a default configuration using [sqlite3_config()].
1329 **
1330 ** The application should never invoke either sqlite3_os_init()
1331 ** or sqlite3_os_end() directly.  The application should only invoke
1332 ** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
1333 ** interface is called automatically by sqlite3_initialize() and
1334 ** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
1335 ** implementations for sqlite3_os_init() and sqlite3_os_end()
1336 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
1337 ** When [custom builds | built for other platforms]
1338 ** (using the [SQLITE_OS_OTHER=1] compile-time
1339 ** option) the application must supply a suitable implementation for
1340 ** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
1341 ** implementation of sqlite3_os_init() or sqlite3_os_end()
1342 ** must return [SQLITE_OK] on success and some other [error code] upon
1343 ** failure.
1344 */
1345 SQLITE_API int SQLITE_STDCALL sqlite3_initialize(void);
1346 SQLITE_API int SQLITE_STDCALL sqlite3_shutdown(void);
1347 SQLITE_API int SQLITE_STDCALL sqlite3_os_init(void);
1348 SQLITE_API int SQLITE_STDCALL sqlite3_os_end(void);
1349 
1350 /*
1351 ** CAPI3REF: Configuring The SQLite Library
1352 **
1353 ** The sqlite3_config() interface is used to make global configuration
1354 ** changes to SQLite in order to tune SQLite to the specific needs of
1355 ** the application.  The default configuration is recommended for most
1356 ** applications and so this routine is usually not necessary.  It is
1357 ** provided to support rare applications with unusual needs.
1358 **
1359 ** The sqlite3_config() interface is not threadsafe.  The application
1360 ** must insure that no other SQLite interfaces are invoked by other
1361 ** threads while sqlite3_config() is running.  Furthermore, sqlite3_config()
1362 ** may only be invoked prior to library initialization using
1363 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
1364 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
1365 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
1366 ** Note, however, that ^sqlite3_config() can be called as part of the
1367 ** implementation of an application-defined [sqlite3_os_init()].
1368 **
1369 ** The first argument to sqlite3_config() is an integer
1370 ** [configuration option] that determines
1371 ** what property of SQLite is to be configured.  Subsequent arguments
1372 ** vary depending on the [configuration option]
1373 ** in the first argument.
1374 **
1375 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
1376 ** ^If the option is unknown or SQLite is unable to set the option
1377 ** then this routine returns a non-zero [error code].
1378 */
1379 SQLITE_API int SQLITE_CDECL sqlite3_config(int, ...);
1380 
1381 /*
1382 ** CAPI3REF: Configure database connections
1383 ** METHOD: sqlite3
1384 **
1385 ** The sqlite3_db_config() interface is used to make configuration
1386 ** changes to a [database connection].  The interface is similar to
1387 ** [sqlite3_config()] except that the changes apply to a single
1388 ** [database connection] (specified in the first argument).
1389 **
1390 ** The second argument to sqlite3_db_config(D,V,...)  is the
1391 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
1392 ** that indicates what aspect of the [database connection] is being configured.
1393 ** Subsequent arguments vary depending on the configuration verb.
1394 **
1395 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
1396 ** the call is considered successful.
1397 */
1398 SQLITE_API int SQLITE_CDECL sqlite3_db_config(sqlite3*, int op, ...);
1399 
1400 /*
1401 ** CAPI3REF: Memory Allocation Routines
1402 **
1403 ** An instance of this object defines the interface between SQLite
1404 ** and low-level memory allocation routines.
1405 **
1406 ** This object is used in only one place in the SQLite interface.
1407 ** A pointer to an instance of this object is the argument to
1408 ** [sqlite3_config()] when the configuration option is
1409 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
1410 ** By creating an instance of this object
1411 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
1412 ** during configuration, an application can specify an alternative
1413 ** memory allocation subsystem for SQLite to use for all of its
1414 ** dynamic memory needs.
1415 **
1416 ** Note that SQLite comes with several [built-in memory allocators]
1417 ** that are perfectly adequate for the overwhelming majority of applications
1418 ** and that this object is only useful to a tiny minority of applications
1419 ** with specialized memory allocation requirements.  This object is
1420 ** also used during testing of SQLite in order to specify an alternative
1421 ** memory allocator that simulates memory out-of-memory conditions in
1422 ** order to verify that SQLite recovers gracefully from such
1423 ** conditions.
1424 **
1425 ** The xMalloc, xRealloc, and xFree methods must work like the
1426 ** malloc(), realloc() and free() functions from the standard C library.
1427 ** ^SQLite guarantees that the second argument to
1428 ** xRealloc is always a value returned by a prior call to xRoundup.
1429 **
1430 ** xSize should return the allocated size of a memory allocation
1431 ** previously obtained from xMalloc or xRealloc.  The allocated size
1432 ** is always at least as big as the requested size but may be larger.
1433 **
1434 ** The xRoundup method returns what would be the allocated size of
1435 ** a memory allocation given a particular requested size.  Most memory
1436 ** allocators round up memory allocations at least to the next multiple
1437 ** of 8.  Some allocators round up to a larger multiple or to a power of 2.
1438 ** Every memory allocation request coming in through [sqlite3_malloc()]
1439 ** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0,
1440 ** that causes the corresponding memory allocation to fail.
1441 **
1442 ** The xInit method initializes the memory allocator.  For example,
1443 ** it might allocate any require mutexes or initialize internal data
1444 ** structures.  The xShutdown method is invoked (indirectly) by
1445 ** [sqlite3_shutdown()] and should deallocate any resources acquired
1446 ** by xInit.  The pAppData pointer is used as the only parameter to
1447 ** xInit and xShutdown.
1448 **
1449 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
1450 ** the xInit method, so the xInit method need not be threadsafe.  The
1451 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
1452 ** not need to be threadsafe either.  For all other methods, SQLite
1453 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
1454 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
1455 ** it is by default) and so the methods are automatically serialized.
1456 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
1457 ** methods must be threadsafe or else make their own arrangements for
1458 ** serialization.
1459 **
1460 ** SQLite will never invoke xInit() more than once without an intervening
1461 ** call to xShutdown().
1462 */
1463 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
1464 struct sqlite3_mem_methods {
1465   void *(*xMalloc)(int);         /* Memory allocation function */
1466   void (*xFree)(void*);          /* Free a prior allocation */
1467   void *(*xRealloc)(void*,int);  /* Resize an allocation */
1468   int (*xSize)(void*);           /* Return the size of an allocation */
1469   int (*xRoundup)(int);          /* Round up request size to allocation size */
1470   int (*xInit)(void*);           /* Initialize the memory allocator */
1471   void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
1472   void *pAppData;                /* Argument to xInit() and xShutdown() */
1473 };
1474 
1475 /*
1476 ** CAPI3REF: Configuration Options
1477 ** KEYWORDS: {configuration option}
1478 **
1479 ** These constants are the available integer configuration options that
1480 ** can be passed as the first argument to the [sqlite3_config()] interface.
1481 **
1482 ** New configuration options may be added in future releases of SQLite.
1483 ** Existing configuration options might be discontinued.  Applications
1484 ** should check the return code from [sqlite3_config()] to make sure that
1485 ** the call worked.  The [sqlite3_config()] interface will return a
1486 ** non-zero [error code] if a discontinued or unsupported configuration option
1487 ** is invoked.
1488 **
1489 ** <dl>
1490 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
1491 ** <dd>There are no arguments to this option.  ^This option sets the
1492 ** [threading mode] to Single-thread.  In other words, it disables
1493 ** all mutexing and puts SQLite into a mode where it can only be used
1494 ** by a single thread.   ^If SQLite is compiled with
1495 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1496 ** it is not possible to change the [threading mode] from its default
1497 ** value of Single-thread and so [sqlite3_config()] will return
1498 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
1499 ** configuration option.</dd>
1500 **
1501 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
1502 ** <dd>There are no arguments to this option.  ^This option sets the
1503 ** [threading mode] to Multi-thread.  In other words, it disables
1504 ** mutexing on [database connection] and [prepared statement] objects.
1505 ** The application is responsible for serializing access to
1506 ** [database connections] and [prepared statements].  But other mutexes
1507 ** are enabled so that SQLite will be safe to use in a multi-threaded
1508 ** environment as long as no two threads attempt to use the same
1509 ** [database connection] at the same time.  ^If SQLite is compiled with
1510 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1511 ** it is not possible to set the Multi-thread [threading mode] and
1512 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1513 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
1514 **
1515 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
1516 ** <dd>There are no arguments to this option.  ^This option sets the
1517 ** [threading mode] to Serialized. In other words, this option enables
1518 ** all mutexes including the recursive
1519 ** mutexes on [database connection] and [prepared statement] objects.
1520 ** In this mode (which is the default when SQLite is compiled with
1521 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
1522 ** to [database connections] and [prepared statements] so that the
1523 ** application is free to use the same [database connection] or the
1524 ** same [prepared statement] in different threads at the same time.
1525 ** ^If SQLite is compiled with
1526 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1527 ** it is not possible to set the Serialized [threading mode] and
1528 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
1529 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
1530 **
1531 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
1532 ** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
1533 ** a pointer to an instance of the [sqlite3_mem_methods] structure.
1534 ** The argument specifies
1535 ** alternative low-level memory allocation routines to be used in place of
1536 ** the memory allocation routines built into SQLite.)^ ^SQLite makes
1537 ** its own private copy of the content of the [sqlite3_mem_methods] structure
1538 ** before the [sqlite3_config()] call returns.</dd>
1539 **
1540 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
1541 ** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
1542 ** is a pointer to an instance of the [sqlite3_mem_methods] structure.
1543 ** The [sqlite3_mem_methods]
1544 ** structure is filled with the currently defined memory allocation routines.)^
1545 ** This option can be used to overload the default memory allocation
1546 ** routines with a wrapper that simulations memory allocation failure or
1547 ** tracks memory usage, for example. </dd>
1548 **
1549 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
1550 ** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
1551 ** interpreted as a boolean, which enables or disables the collection of
1552 ** memory allocation statistics. ^(When memory allocation statistics are
1553 ** disabled, the following SQLite interfaces become non-operational:
1554 **   <ul>
1555 **   <li> [sqlite3_memory_used()]
1556 **   <li> [sqlite3_memory_highwater()]
1557 **   <li> [sqlite3_soft_heap_limit64()]
1558 **   <li> [sqlite3_status64()]
1559 **   </ul>)^
1560 ** ^Memory allocation statistics are enabled by default unless SQLite is
1561 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
1562 ** allocation statistics are disabled by default.
1563 ** </dd>
1564 **
1565 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
1566 ** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer
1567 ** that SQLite can use for scratch memory.  ^(There are three arguments
1568 ** to SQLITE_CONFIG_SCRATCH:  A pointer an 8-byte
1569 ** aligned memory buffer from which the scratch allocations will be
1570 ** drawn, the size of each scratch allocation (sz),
1571 ** and the maximum number of scratch allocations (N).)^
1572 ** The first argument must be a pointer to an 8-byte aligned buffer
1573 ** of at least sz*N bytes of memory.
1574 ** ^SQLite will not use more than one scratch buffers per thread.
1575 ** ^SQLite will never request a scratch buffer that is more than 6
1576 ** times the database page size.
1577 ** ^If SQLite needs needs additional
1578 ** scratch memory beyond what is provided by this configuration option, then
1579 ** [sqlite3_malloc()] will be used to obtain the memory needed.<p>
1580 ** ^When the application provides any amount of scratch memory using
1581 ** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large
1582 ** [sqlite3_malloc|heap allocations].
1583 ** This can help [Robson proof|prevent memory allocation failures] due to heap
1584 ** fragmentation in low-memory embedded systems.
1585 ** </dd>
1586 **
1587 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
1588 ** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a static memory buffer
1589 ** that SQLite can use for the database page cache with the default page
1590 ** cache implementation.
1591 ** This configuration should not be used if an application-define page
1592 ** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]
1593 ** configuration option.
1594 ** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
1595 ** 8-byte aligned
1596 ** memory, the size of each page buffer (sz), and the number of pages (N).
1597 ** The sz argument should be the size of the largest database page
1598 ** (a power of two between 512 and 65536) plus some extra bytes for each
1599 ** page header.  ^The number of extra bytes needed by the page header
1600 ** can be determined using the [SQLITE_CONFIG_PCACHE_HDRSZ] option
1601 ** to [sqlite3_config()].
1602 ** ^It is harmless, apart from the wasted memory,
1603 ** for the sz parameter to be larger than necessary.  The first
1604 ** argument should pointer to an 8-byte aligned block of memory that
1605 ** is at least sz*N bytes of memory, otherwise subsequent behavior is
1606 ** undefined.
1607 ** ^SQLite will use the memory provided by the first argument to satisfy its
1608 ** memory needs for the first N pages that it adds to cache.  ^If additional
1609 ** page cache memory is needed beyond what is provided by this option, then
1610 ** SQLite goes to [sqlite3_malloc()] for the additional storage space.</dd>
1611 **
1612 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
1613 ** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
1614 ** that SQLite will use for all of its dynamic memory allocation needs
1615 ** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and
1616 ** [SQLITE_CONFIG_PAGECACHE].
1617 ** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
1618 ** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
1619 ** [SQLITE_ERROR] if invoked otherwise.
1620 ** ^There are three arguments to SQLITE_CONFIG_HEAP:
1621 ** An 8-byte aligned pointer to the memory,
1622 ** the number of bytes in the memory buffer, and the minimum allocation size.
1623 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
1624 ** to using its default memory allocator (the system malloc() implementation),
1625 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
1626 ** memory pointer is not NULL then the alternative memory
1627 ** allocator is engaged to handle all of SQLites memory allocation needs.
1628 ** The first pointer (the memory pointer) must be aligned to an 8-byte
1629 ** boundary or subsequent behavior of SQLite will be undefined.
1630 ** The minimum allocation size is capped at 2**12. Reasonable values
1631 ** for the minimum allocation size are 2**5 through 2**8.</dd>
1632 **
1633 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
1634 ** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
1635 ** pointer to an instance of the [sqlite3_mutex_methods] structure.
1636 ** The argument specifies alternative low-level mutex routines to be used
1637 ** in place the mutex routines built into SQLite.)^  ^SQLite makes a copy of
1638 ** the content of the [sqlite3_mutex_methods] structure before the call to
1639 ** [sqlite3_config()] returns. ^If SQLite is compiled with
1640 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1641 ** the entire mutexing subsystem is omitted from the build and hence calls to
1642 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
1643 ** return [SQLITE_ERROR].</dd>
1644 **
1645 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
1646 ** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
1647 ** is a pointer to an instance of the [sqlite3_mutex_methods] structure.  The
1648 ** [sqlite3_mutex_methods]
1649 ** structure is filled with the currently defined mutex routines.)^
1650 ** This option can be used to overload the default mutex allocation
1651 ** routines with a wrapper used to track mutex usage for performance
1652 ** profiling or testing, for example.   ^If SQLite is compiled with
1653 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
1654 ** the entire mutexing subsystem is omitted from the build and hence calls to
1655 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
1656 ** return [SQLITE_ERROR].</dd>
1657 **
1658 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
1659 ** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
1660 ** the default size of lookaside memory on each [database connection].
1661 ** The first argument is the
1662 ** size of each lookaside buffer slot and the second is the number of
1663 ** slots allocated to each database connection.)^  ^(SQLITE_CONFIG_LOOKASIDE
1664 ** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
1665 ** option to [sqlite3_db_config()] can be used to change the lookaside
1666 ** configuration on individual connections.)^ </dd>
1667 **
1668 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
1669 ** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
1670 ** a pointer to an [sqlite3_pcache_methods2] object.  This object specifies
1671 ** the interface to a custom page cache implementation.)^
1672 ** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
1673 **
1674 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
1675 ** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
1676 ** is a pointer to an [sqlite3_pcache_methods2] object.  SQLite copies of
1677 ** the current page cache implementation into that object.)^ </dd>
1678 **
1679 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
1680 ** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
1681 ** global [error log].
1682 ** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
1683 ** function with a call signature of void(*)(void*,int,const char*),
1684 ** and a pointer to void. ^If the function pointer is not NULL, it is
1685 ** invoked by [sqlite3_log()] to process each logging event.  ^If the
1686 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
1687 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
1688 ** passed through as the first parameter to the application-defined logger
1689 ** function whenever that function is invoked.  ^The second parameter to
1690 ** the logger function is a copy of the first parameter to the corresponding
1691 ** [sqlite3_log()] call and is intended to be a [result code] or an
1692 ** [extended result code].  ^The third parameter passed to the logger is
1693 ** log message after formatting via [sqlite3_snprintf()].
1694 ** The SQLite logging interface is not reentrant; the logger function
1695 ** supplied by the application must not invoke any SQLite interface.
1696 ** In a multi-threaded application, the application-defined logger
1697 ** function must be threadsafe. </dd>
1698 **
1699 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
1700 ** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
1701 ** If non-zero, then URI handling is globally enabled. If the parameter is zero,
1702 ** then URI handling is globally disabled.)^ ^If URI handling is globally
1703 ** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
1704 ** [sqlite3_open16()] or
1705 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
1706 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
1707 ** connection is opened. ^If it is globally disabled, filenames are
1708 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
1709 ** database connection is opened. ^(By default, URI handling is globally
1710 ** disabled. The default value may be changed by compiling with the
1711 ** [SQLITE_USE_URI] symbol defined.)^
1712 **
1713 ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
1714 ** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
1715 ** argument which is interpreted as a boolean in order to enable or disable
1716 ** the use of covering indices for full table scans in the query optimizer.
1717 ** ^The default setting is determined
1718 ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
1719 ** if that compile-time option is omitted.
1720 ** The ability to disable the use of covering indices for full table scans
1721 ** is because some incorrectly coded legacy applications might malfunction
1722 ** when the optimization is enabled.  Providing the ability to
1723 ** disable the optimization allows the older, buggy application code to work
1724 ** without change even with newer versions of SQLite.
1725 **
1726 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
1727 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
1728 ** <dd> These options are obsolete and should not be used by new code.
1729 ** They are retained for backwards compatibility but are now no-ops.
1730 ** </dd>
1731 **
1732 ** [[SQLITE_CONFIG_SQLLOG]]
1733 ** <dt>SQLITE_CONFIG_SQLLOG
1734 ** <dd>This option is only available if sqlite is compiled with the
1735 ** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
1736 ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
1737 ** The second should be of type (void*). The callback is invoked by the library
1738 ** in three separate circumstances, identified by the value passed as the
1739 ** fourth parameter. If the fourth parameter is 0, then the database connection
1740 ** passed as the second argument has just been opened. The third argument
1741 ** points to a buffer containing the name of the main database file. If the
1742 ** fourth parameter is 1, then the SQL statement that the third parameter
1743 ** points to has just been executed. Or, if the fourth parameter is 2, then
1744 ** the connection being passed as the second parameter is being closed. The
1745 ** third parameter is passed NULL In this case.  An example of using this
1746 ** configuration option can be seen in the "test_sqllog.c" source file in
1747 ** the canonical SQLite source tree.</dd>
1748 **
1749 ** [[SQLITE_CONFIG_MMAP_SIZE]]
1750 ** <dt>SQLITE_CONFIG_MMAP_SIZE
1751 ** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
1752 ** that are the default mmap size limit (the default setting for
1753 ** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
1754 ** ^The default setting can be overridden by each database connection using
1755 ** either the [PRAGMA mmap_size] command, or by using the
1756 ** [SQLITE_FCNTL_MMAP_SIZE] file control.  ^(The maximum allowed mmap size
1757 ** will be silently truncated if necessary so that it does not exceed the
1758 ** compile-time maximum mmap size set by the
1759 ** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
1760 ** ^If either argument to this option is negative, then that argument is
1761 ** changed to its compile-time default.
1762 **
1763 ** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
1764 ** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
1765 ** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
1766 ** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
1767 ** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
1768 ** that specifies the maximum size of the created heap.
1769 **
1770 ** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
1771 ** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
1772 ** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
1773 ** is a pointer to an integer and writes into that integer the number of extra
1774 ** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
1775 ** The amount of extra space required can change depending on the compiler,
1776 ** target platform, and SQLite version.
1777 **
1778 ** [[SQLITE_CONFIG_PMASZ]]
1779 ** <dt>SQLITE_CONFIG_PMASZ
1780 ** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
1781 ** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
1782 ** sorter to that integer.  The default minimum PMA Size is set by the
1783 ** [SQLITE_SORTER_PMASZ] compile-time option.  New threads are launched
1784 ** to help with sort operations when multithreaded sorting
1785 ** is enabled (using the [PRAGMA threads] command) and the amount of content
1786 ** to be sorted exceeds the page size times the minimum of the
1787 ** [PRAGMA cache_size] setting and this value.
1788 ** </dl>
1789 */
1790 #define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
1791 #define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
1792 #define SQLITE_CONFIG_SERIALIZED    3  /* nil */
1793 #define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
1794 #define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
1795 #define SQLITE_CONFIG_SCRATCH       6  /* void*, int sz, int N */
1796 #define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
1797 #define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
1798 #define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
1799 #define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
1800 #define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
1801 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
1802 #define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
1803 #define SQLITE_CONFIG_PCACHE       14  /* no-op */
1804 #define SQLITE_CONFIG_GETPCACHE    15  /* no-op */
1805 #define SQLITE_CONFIG_LOG          16  /* xFunc, void* */
1806 #define SQLITE_CONFIG_URI          17  /* int */
1807 #define SQLITE_CONFIG_PCACHE2      18  /* sqlite3_pcache_methods2* */
1808 #define SQLITE_CONFIG_GETPCACHE2   19  /* sqlite3_pcache_methods2* */
1809 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20  /* int */
1810 #define SQLITE_CONFIG_SQLLOG       21  /* xSqllog, void* */
1811 #define SQLITE_CONFIG_MMAP_SIZE    22  /* sqlite3_int64, sqlite3_int64 */
1812 #define SQLITE_CONFIG_WIN32_HEAPSIZE      23  /* int nByte */
1813 #define SQLITE_CONFIG_PCACHE_HDRSZ        24  /* int *psz */
1814 #define SQLITE_CONFIG_PMASZ               25  /* unsigned int szPma */
1815 
1816 /*
1817 ** CAPI3REF: Database Connection Configuration Options
1818 **
1819 ** These constants are the available integer configuration options that
1820 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
1821 **
1822 ** New configuration options may be added in future releases of SQLite.
1823 ** Existing configuration options might be discontinued.  Applications
1824 ** should check the return code from [sqlite3_db_config()] to make sure that
1825 ** the call worked.  ^The [sqlite3_db_config()] interface will return a
1826 ** non-zero [error code] if a discontinued or unsupported configuration option
1827 ** is invoked.
1828 **
1829 ** <dl>
1830 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
1831 ** <dd> ^This option takes three additional arguments that determine the
1832 ** [lookaside memory allocator] configuration for the [database connection].
1833 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
1834 ** pointer to a memory buffer to use for lookaside memory.
1835 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
1836 ** may be NULL in which case SQLite will allocate the
1837 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
1838 ** size of each lookaside buffer slot.  ^The third argument is the number of
1839 ** slots.  The size of the buffer in the first argument must be greater than
1840 ** or equal to the product of the second and third arguments.  The buffer
1841 ** must be aligned to an 8-byte boundary.  ^If the second argument to
1842 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
1843 ** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
1844 ** configuration for a database connection can only be changed when that
1845 ** connection is not currently using lookaside memory, or in other words
1846 ** when the "current value" returned by
1847 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
1848 ** Any attempt to change the lookaside memory configuration when lookaside
1849 ** memory is in use leaves the configuration unchanged and returns
1850 ** [SQLITE_BUSY].)^</dd>
1851 **
1852 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
1853 ** <dd> ^This option is used to enable or disable the enforcement of
1854 ** [foreign key constraints].  There should be two additional arguments.
1855 ** The first argument is an integer which is 0 to disable FK enforcement,
1856 ** positive to enable FK enforcement or negative to leave FK enforcement
1857 ** unchanged.  The second parameter is a pointer to an integer into which
1858 ** is written 0 or 1 to indicate whether FK enforcement is off or on
1859 ** following this call.  The second parameter may be a NULL pointer, in
1860 ** which case the FK enforcement setting is not reported back. </dd>
1861 **
1862 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
1863 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
1864 ** There should be two additional arguments.
1865 ** The first argument is an integer which is 0 to disable triggers,
1866 ** positive to enable triggers or negative to leave the setting unchanged.
1867 ** The second parameter is a pointer to an integer into which
1868 ** is written 0 or 1 to indicate whether triggers are disabled or enabled
1869 ** following this call.  The second parameter may be a NULL pointer, in
1870 ** which case the trigger setting is not reported back. </dd>
1871 **
1872 ** </dl>
1873 */
1874 #define SQLITE_DBCONFIG_LOOKASIDE       1001  /* void* int int */
1875 #define SQLITE_DBCONFIG_ENABLE_FKEY     1002  /* int int* */
1876 #define SQLITE_DBCONFIG_ENABLE_TRIGGER  1003  /* int int* */
1877 
1878 
1879 /*
1880 ** CAPI3REF: Enable Or Disable Extended Result Codes
1881 ** METHOD: sqlite3
1882 **
1883 ** ^The sqlite3_extended_result_codes() routine enables or disables the
1884 ** [extended result codes] feature of SQLite. ^The extended result
1885 ** codes are disabled by default for historical compatibility.
1886 */
1887 SQLITE_API int SQLITE_STDCALL sqlite3_extended_result_codes(sqlite3*, int onoff);
1888 
1889 /*
1890 ** CAPI3REF: Last Insert Rowid
1891 ** METHOD: sqlite3
1892 **
1893 ** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
1894 ** has a unique 64-bit signed
1895 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
1896 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
1897 ** names are not also used by explicitly declared columns. ^If
1898 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
1899 ** is another alias for the rowid.
1900 **
1901 ** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the
1902 ** most recent successful [INSERT] into a rowid table or [virtual table]
1903 ** on database connection D.
1904 ** ^Inserts into [WITHOUT ROWID] tables are not recorded.
1905 ** ^If no successful [INSERT]s into rowid tables
1906 ** have ever occurred on the database connection D,
1907 ** then sqlite3_last_insert_rowid(D) returns zero.
1908 **
1909 ** ^(If an [INSERT] occurs within a trigger or within a [virtual table]
1910 ** method, then this routine will return the [rowid] of the inserted
1911 ** row as long as the trigger or virtual table method is running.
1912 ** But once the trigger or virtual table method ends, the value returned
1913 ** by this routine reverts to what it was before the trigger or virtual
1914 ** table method began.)^
1915 **
1916 ** ^An [INSERT] that fails due to a constraint violation is not a
1917 ** successful [INSERT] and does not change the value returned by this
1918 ** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
1919 ** and INSERT OR ABORT make no changes to the return value of this
1920 ** routine when their insertion fails.  ^(When INSERT OR REPLACE
1921 ** encounters a constraint violation, it does not fail.  The
1922 ** INSERT continues to completion after deleting rows that caused
1923 ** the constraint problem so INSERT OR REPLACE will always change
1924 ** the return value of this interface.)^
1925 **
1926 ** ^For the purposes of this routine, an [INSERT] is considered to
1927 ** be successful even if it is subsequently rolled back.
1928 **
1929 ** This function is accessible to SQL statements via the
1930 ** [last_insert_rowid() SQL function].
1931 **
1932 ** If a separate thread performs a new [INSERT] on the same
1933 ** database connection while the [sqlite3_last_insert_rowid()]
1934 ** function is running and thus changes the last insert [rowid],
1935 ** then the value returned by [sqlite3_last_insert_rowid()] is
1936 ** unpredictable and might not equal either the old or the new
1937 ** last insert [rowid].
1938 */
1939 SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_last_insert_rowid(sqlite3*);
1940 
1941 /*
1942 ** CAPI3REF: Count The Number Of Rows Modified
1943 ** METHOD: sqlite3
1944 **
1945 ** ^This function returns the number of rows modified, inserted or
1946 ** deleted by the most recently completed INSERT, UPDATE or DELETE
1947 ** statement on the database connection specified by the only parameter.
1948 ** ^Executing any other type of SQL statement does not modify the value
1949 ** returned by this function.
1950 **
1951 ** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
1952 ** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
1953 ** [foreign key actions] or [REPLACE] constraint resolution are not counted.
1954 **
1955 ** Changes to a view that are intercepted by
1956 ** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
1957 ** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
1958 ** DELETE statement run on a view is always zero. Only changes made to real
1959 ** tables are counted.
1960 **
1961 ** Things are more complicated if the sqlite3_changes() function is
1962 ** executed while a trigger program is running. This may happen if the
1963 ** program uses the [changes() SQL function], or if some other callback
1964 ** function invokes sqlite3_changes() directly. Essentially:
1965 **
1966 ** <ul>
1967 **   <li> ^(Before entering a trigger program the value returned by
1968 **        sqlite3_changes() function is saved. After the trigger program
1969 **        has finished, the original value is restored.)^
1970 **
1971 **   <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
1972 **        statement sets the value returned by sqlite3_changes()
1973 **        upon completion as normal. Of course, this value will not include
1974 **        any changes performed by sub-triggers, as the sqlite3_changes()
1975 **        value will be saved and restored after each sub-trigger has run.)^
1976 ** </ul>
1977 **
1978 ** ^This means that if the changes() SQL function (or similar) is used
1979 ** by the first INSERT, UPDATE or DELETE statement within a trigger, it
1980 ** returns the value as set when the calling statement began executing.
1981 ** ^If it is used by the second or subsequent such statement within a trigger
1982 ** program, the value returned reflects the number of rows modified by the
1983 ** previous INSERT, UPDATE or DELETE statement within the same trigger.
1984 **
1985 ** See also the [sqlite3_total_changes()] interface, the
1986 ** [count_changes pragma], and the [changes() SQL function].
1987 **
1988 ** If a separate thread makes changes on the same database connection
1989 ** while [sqlite3_changes()] is running then the value returned
1990 ** is unpredictable and not meaningful.
1991 */
1992 SQLITE_API int SQLITE_STDCALL sqlite3_changes(sqlite3*);
1993 
1994 /*
1995 ** CAPI3REF: Total Number Of Rows Modified
1996 ** METHOD: sqlite3
1997 **
1998 ** ^This function returns the total number of rows inserted, modified or
1999 ** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
2000 ** since the database connection was opened, including those executed as
2001 ** part of trigger programs. ^Executing any other type of SQL statement
2002 ** does not affect the value returned by sqlite3_total_changes().
2003 **
2004 ** ^Changes made as part of [foreign key actions] are included in the
2005 ** count, but those made as part of REPLACE constraint resolution are
2006 ** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
2007 ** are not counted.
2008 **
2009 ** See also the [sqlite3_changes()] interface, the
2010 ** [count_changes pragma], and the [total_changes() SQL function].
2011 **
2012 ** If a separate thread makes changes on the same database connection
2013 ** while [sqlite3_total_changes()] is running then the value
2014 ** returned is unpredictable and not meaningful.
2015 */
2016 SQLITE_API int SQLITE_STDCALL sqlite3_total_changes(sqlite3*);
2017 
2018 /*
2019 ** CAPI3REF: Interrupt A Long-Running Query
2020 ** METHOD: sqlite3
2021 **
2022 ** ^This function causes any pending database operation to abort and
2023 ** return at its earliest opportunity. This routine is typically
2024 ** called in response to a user action such as pressing "Cancel"
2025 ** or Ctrl-C where the user wants a long query operation to halt
2026 ** immediately.
2027 **
2028 ** ^It is safe to call this routine from a thread different from the
2029 ** thread that is currently running the database operation.  But it
2030 ** is not safe to call this routine with a [database connection] that
2031 ** is closed or might close before sqlite3_interrupt() returns.
2032 **
2033 ** ^If an SQL operation is very nearly finished at the time when
2034 ** sqlite3_interrupt() is called, then it might not have an opportunity
2035 ** to be interrupted and might continue to completion.
2036 **
2037 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
2038 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
2039 ** that is inside an explicit transaction, then the entire transaction
2040 ** will be rolled back automatically.
2041 **
2042 ** ^The sqlite3_interrupt(D) call is in effect until all currently running
2043 ** SQL statements on [database connection] D complete.  ^Any new SQL statements
2044 ** that are started after the sqlite3_interrupt() call and before the
2045 ** running statements reaches zero are interrupted as if they had been
2046 ** running prior to the sqlite3_interrupt() call.  ^New SQL statements
2047 ** that are started after the running statement count reaches zero are
2048 ** not effected by the sqlite3_interrupt().
2049 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
2050 ** SQL statements is a no-op and has no effect on SQL statements
2051 ** that are started after the sqlite3_interrupt() call returns.
2052 **
2053 ** If the database connection closes while [sqlite3_interrupt()]
2054 ** is running then bad things will likely happen.
2055 */
2056 SQLITE_API void SQLITE_STDCALL sqlite3_interrupt(sqlite3*);
2057 
2058 /*
2059 ** CAPI3REF: Determine If An SQL Statement Is Complete
2060 **
2061 ** These routines are useful during command-line input to determine if the
2062 ** currently entered text seems to form a complete SQL statement or
2063 ** if additional input is needed before sending the text into
2064 ** SQLite for parsing.  ^These routines return 1 if the input string
2065 ** appears to be a complete SQL statement.  ^A statement is judged to be
2066 ** complete if it ends with a semicolon token and is not a prefix of a
2067 ** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
2068 ** string literals or quoted identifier names or comments are not
2069 ** independent tokens (they are part of the token in which they are
2070 ** embedded) and thus do not count as a statement terminator.  ^Whitespace
2071 ** and comments that follow the final semicolon are ignored.
2072 **
2073 ** ^These routines return 0 if the statement is incomplete.  ^If a
2074 ** memory allocation fails, then SQLITE_NOMEM is returned.
2075 **
2076 ** ^These routines do not parse the SQL statements thus
2077 ** will not detect syntactically incorrect SQL.
2078 **
2079 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
2080 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
2081 ** automatically by sqlite3_complete16().  If that initialization fails,
2082 ** then the return value from sqlite3_complete16() will be non-zero
2083 ** regardless of whether or not the input SQL is complete.)^
2084 **
2085 ** The input to [sqlite3_complete()] must be a zero-terminated
2086 ** UTF-8 string.
2087 **
2088 ** The input to [sqlite3_complete16()] must be a zero-terminated
2089 ** UTF-16 string in native byte order.
2090 */
2091 SQLITE_API int SQLITE_STDCALL sqlite3_complete(const char *sql);
2092 SQLITE_API int SQLITE_STDCALL sqlite3_complete16(const void *sql);
2093 
2094 /*
2095 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
2096 ** KEYWORDS: {busy-handler callback} {busy handler}
2097 ** METHOD: sqlite3
2098 **
2099 ** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
2100 ** that might be invoked with argument P whenever
2101 ** an attempt is made to access a database table associated with
2102 ** [database connection] D when another thread
2103 ** or process has the table locked.
2104 ** The sqlite3_busy_handler() interface is used to implement
2105 ** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
2106 **
2107 ** ^If the busy callback is NULL, then [SQLITE_BUSY]
2108 ** is returned immediately upon encountering the lock.  ^If the busy callback
2109 ** is not NULL, then the callback might be invoked with two arguments.
2110 **
2111 ** ^The first argument to the busy handler is a copy of the void* pointer which
2112 ** is the third argument to sqlite3_busy_handler().  ^The second argument to
2113 ** the busy handler callback is the number of times that the busy handler has
2114 ** been invoked previously for the same locking event.  ^If the
2115 ** busy callback returns 0, then no additional attempts are made to
2116 ** access the database and [SQLITE_BUSY] is returned
2117 ** to the application.
2118 ** ^If the callback returns non-zero, then another attempt
2119 ** is made to access the database and the cycle repeats.
2120 **
2121 ** The presence of a busy handler does not guarantee that it will be invoked
2122 ** when there is lock contention. ^If SQLite determines that invoking the busy
2123 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
2124 ** to the application instead of invoking the
2125 ** busy handler.
2126 ** Consider a scenario where one process is holding a read lock that
2127 ** it is trying to promote to a reserved lock and
2128 ** a second process is holding a reserved lock that it is trying
2129 ** to promote to an exclusive lock.  The first process cannot proceed
2130 ** because it is blocked by the second and the second process cannot
2131 ** proceed because it is blocked by the first.  If both processes
2132 ** invoke the busy handlers, neither will make any progress.  Therefore,
2133 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
2134 ** will induce the first process to release its read lock and allow
2135 ** the second process to proceed.
2136 **
2137 ** ^The default busy callback is NULL.
2138 **
2139 ** ^(There can only be a single busy handler defined for each
2140 ** [database connection].  Setting a new busy handler clears any
2141 ** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
2142 ** or evaluating [PRAGMA busy_timeout=N] will change the
2143 ** busy handler and thus clear any previously set busy handler.
2144 **
2145 ** The busy callback should not take any actions which modify the
2146 ** database connection that invoked the busy handler.  In other words,
2147 ** the busy handler is not reentrant.  Any such actions
2148 ** result in undefined behavior.
2149 **
2150 ** A busy handler must not close the database connection
2151 ** or [prepared statement] that invoked the busy handler.
2152 */
2153 SQLITE_API int SQLITE_STDCALL sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
2154 
2155 /*
2156 ** CAPI3REF: Set A Busy Timeout
2157 ** METHOD: sqlite3
2158 **
2159 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
2160 ** for a specified amount of time when a table is locked.  ^The handler
2161 ** will sleep multiple times until at least "ms" milliseconds of sleeping
2162 ** have accumulated.  ^After at least "ms" milliseconds of sleeping,
2163 ** the handler returns 0 which causes [sqlite3_step()] to return
2164 ** [SQLITE_BUSY].
2165 **
2166 ** ^Calling this routine with an argument less than or equal to zero
2167 ** turns off all busy handlers.
2168 **
2169 ** ^(There can only be a single busy handler for a particular
2170 ** [database connection] at any given moment.  If another busy handler
2171 ** was defined  (using [sqlite3_busy_handler()]) prior to calling
2172 ** this routine, that other busy handler is cleared.)^
2173 **
2174 ** See also:  [PRAGMA busy_timeout]
2175 */
2176 SQLITE_API int SQLITE_STDCALL sqlite3_busy_timeout(sqlite3*, int ms);
2177 
2178 /*
2179 ** CAPI3REF: Convenience Routines For Running Queries
2180 ** METHOD: sqlite3
2181 **
2182 ** This is a legacy interface that is preserved for backwards compatibility.
2183 ** Use of this interface is not recommended.
2184 **
2185 ** Definition: A <b>result table</b> is memory data structure created by the
2186 ** [sqlite3_get_table()] interface.  A result table records the
2187 ** complete query results from one or more queries.
2188 **
2189 ** The table conceptually has a number of rows and columns.  But
2190 ** these numbers are not part of the result table itself.  These
2191 ** numbers are obtained separately.  Let N be the number of rows
2192 ** and M be the number of columns.
2193 **
2194 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
2195 ** There are (N+1)*M elements in the array.  The first M pointers point
2196 ** to zero-terminated strings that  contain the names of the columns.
2197 ** The remaining entries all point to query results.  NULL values result
2198 ** in NULL pointers.  All other values are in their UTF-8 zero-terminated
2199 ** string representation as returned by [sqlite3_column_text()].
2200 **
2201 ** A result table might consist of one or more memory allocations.
2202 ** It is not safe to pass a result table directly to [sqlite3_free()].
2203 ** A result table should be deallocated using [sqlite3_free_table()].
2204 **
2205 ** ^(As an example of the result table format, suppose a query result
2206 ** is as follows:
2207 **
2208 ** <blockquote><pre>
2209 **        Name        | Age
2210 **        -----------------------
2211 **        Alice       | 43
2212 **        Bob         | 28
2213 **        Cindy       | 21
2214 ** </pre></blockquote>
2215 **
2216 ** There are two column (M==2) and three rows (N==3).  Thus the
2217 ** result table has 8 entries.  Suppose the result table is stored
2218 ** in an array names azResult.  Then azResult holds this content:
2219 **
2220 ** <blockquote><pre>
2221 **        azResult&#91;0] = "Name";
2222 **        azResult&#91;1] = "Age";
2223 **        azResult&#91;2] = "Alice";
2224 **        azResult&#91;3] = "43";
2225 **        azResult&#91;4] = "Bob";
2226 **        azResult&#91;5] = "28";
2227 **        azResult&#91;6] = "Cindy";
2228 **        azResult&#91;7] = "21";
2229 ** </pre></blockquote>)^
2230 **
2231 ** ^The sqlite3_get_table() function evaluates one or more
2232 ** semicolon-separated SQL statements in the zero-terminated UTF-8
2233 ** string of its 2nd parameter and returns a result table to the
2234 ** pointer given in its 3rd parameter.
2235 **
2236 ** After the application has finished with the result from sqlite3_get_table(),
2237 ** it must pass the result table pointer to sqlite3_free_table() in order to
2238 ** release the memory that was malloced.  Because of the way the
2239 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
2240 ** function must not try to call [sqlite3_free()] directly.  Only
2241 ** [sqlite3_free_table()] is able to release the memory properly and safely.
2242 **
2243 ** The sqlite3_get_table() interface is implemented as a wrapper around
2244 ** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
2245 ** to any internal data structures of SQLite.  It uses only the public
2246 ** interface defined here.  As a consequence, errors that occur in the
2247 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
2248 ** reflected in subsequent calls to [sqlite3_errcode()] or
2249 ** [sqlite3_errmsg()].
2250 */
2251 SQLITE_API int SQLITE_STDCALL sqlite3_get_table(
2252   sqlite3 *db,          /* An open database */
2253   const char *zSql,     /* SQL to be evaluated */
2254   char ***pazResult,    /* Results of the query */
2255   int *pnRow,           /* Number of result rows written here */
2256   int *pnColumn,        /* Number of result columns written here */
2257   char **pzErrmsg       /* Error msg written here */
2258 );
2259 SQLITE_API void SQLITE_STDCALL sqlite3_free_table(char **result);
2260 
2261 /*
2262 ** CAPI3REF: Formatted String Printing Functions
2263 **
2264 ** These routines are work-alikes of the "printf()" family of functions
2265 ** from the standard C library.
2266 ** These routines understand most of the common K&R formatting options,
2267 ** plus some additional non-standard formats, detailed below.
2268 ** Note that some of the more obscure formatting options from recent
2269 ** C-library standards are omitted from this implementation.
2270 **
2271 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
2272 ** results into memory obtained from [sqlite3_malloc()].
2273 ** The strings returned by these two routines should be
2274 ** released by [sqlite3_free()].  ^Both routines return a
2275 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
2276 ** memory to hold the resulting string.
2277 **
2278 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
2279 ** the standard C library.  The result is written into the
2280 ** buffer supplied as the second parameter whose size is given by
2281 ** the first parameter. Note that the order of the
2282 ** first two parameters is reversed from snprintf().)^  This is an
2283 ** historical accident that cannot be fixed without breaking
2284 ** backwards compatibility.  ^(Note also that sqlite3_snprintf()
2285 ** returns a pointer to its buffer instead of the number of
2286 ** characters actually written into the buffer.)^  We admit that
2287 ** the number of characters written would be a more useful return
2288 ** value but we cannot change the implementation of sqlite3_snprintf()
2289 ** now without breaking compatibility.
2290 **
2291 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
2292 ** guarantees that the buffer is always zero-terminated.  ^The first
2293 ** parameter "n" is the total size of the buffer, including space for
2294 ** the zero terminator.  So the longest string that can be completely
2295 ** written will be n-1 characters.
2296 **
2297 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
2298 **
2299 ** These routines all implement some additional formatting
2300 ** options that are useful for constructing SQL statements.
2301 ** All of the usual printf() formatting options apply.  In addition, there
2302 ** is are "%q", "%Q", "%w" and "%z" options.
2303 **
2304 ** ^(The %q option works like %s in that it substitutes a nul-terminated
2305 ** string from the argument list.  But %q also doubles every '\'' character.
2306 ** %q is designed for use inside a string literal.)^  By doubling each '\''
2307 ** character it escapes that character and allows it to be inserted into
2308 ** the string.
2309 **
2310 ** For example, assume the string variable zText contains text as follows:
2311 **
2312 ** <blockquote><pre>
2313 **  char *zText = "It's a happy day!";
2314 ** </pre></blockquote>
2315 **
2316 ** One can use this text in an SQL statement as follows:
2317 **
2318 ** <blockquote><pre>
2319 **  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
2320 **  sqlite3_exec(db, zSQL, 0, 0, 0);
2321 **  sqlite3_free(zSQL);
2322 ** </pre></blockquote>
2323 **
2324 ** Because the %q format string is used, the '\'' character in zText
2325 ** is escaped and the SQL generated is as follows:
2326 **
2327 ** <blockquote><pre>
2328 **  INSERT INTO table1 VALUES('It''s a happy day!')
2329 ** </pre></blockquote>
2330 **
2331 ** This is correct.  Had we used %s instead of %q, the generated SQL
2332 ** would have looked like this:
2333 **
2334 ** <blockquote><pre>
2335 **  INSERT INTO table1 VALUES('It's a happy day!');
2336 ** </pre></blockquote>
2337 **
2338 ** This second example is an SQL syntax error.  As a general rule you should
2339 ** always use %q instead of %s when inserting text into a string literal.
2340 **
2341 ** ^(The %Q option works like %q except it also adds single quotes around
2342 ** the outside of the total string.  Additionally, if the parameter in the
2343 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
2344 ** single quotes).)^  So, for example, one could say:
2345 **
2346 ** <blockquote><pre>
2347 **  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
2348 **  sqlite3_exec(db, zSQL, 0, 0, 0);
2349 **  sqlite3_free(zSQL);
2350 ** </pre></blockquote>
2351 **
2352 ** The code above will render a correct SQL statement in the zSQL
2353 ** variable even if the zText variable is a NULL pointer.
2354 **
2355 ** ^(The "%w" formatting option is like "%q" except that it expects to
2356 ** be contained within double-quotes instead of single quotes, and it
2357 ** escapes the double-quote character instead of the single-quote
2358 ** character.)^  The "%w" formatting option is intended for safely inserting
2359 ** table and column names into a constructed SQL statement.
2360 **
2361 ** ^(The "%z" formatting option works like "%s" but with the
2362 ** addition that after the string has been read and copied into
2363 ** the result, [sqlite3_free()] is called on the input string.)^
2364 */
2365 SQLITE_API char *SQLITE_CDECL sqlite3_mprintf(const char*,...);
2366 SQLITE_API char *SQLITE_STDCALL sqlite3_vmprintf(const char*, va_list);
2367 SQLITE_API char *SQLITE_CDECL sqlite3_snprintf(int,char*,const char*, ...);
2368 SQLITE_API char *SQLITE_STDCALL sqlite3_vsnprintf(int,char*,const char*, va_list);
2369 
2370 /*
2371 ** CAPI3REF: Memory Allocation Subsystem
2372 **
2373 ** The SQLite core uses these three routines for all of its own
2374 ** internal memory allocation needs. "Core" in the previous sentence
2375 ** does not include operating-system specific VFS implementation.  The
2376 ** Windows VFS uses native malloc() and free() for some operations.
2377 **
2378 ** ^The sqlite3_malloc() routine returns a pointer to a block
2379 ** of memory at least N bytes in length, where N is the parameter.
2380 ** ^If sqlite3_malloc() is unable to obtain sufficient free
2381 ** memory, it returns a NULL pointer.  ^If the parameter N to
2382 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
2383 ** a NULL pointer.
2384 **
2385 ** ^The sqlite3_malloc64(N) routine works just like
2386 ** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
2387 ** of a signed 32-bit integer.
2388 **
2389 ** ^Calling sqlite3_free() with a pointer previously returned
2390 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
2391 ** that it might be reused.  ^The sqlite3_free() routine is
2392 ** a no-op if is called with a NULL pointer.  Passing a NULL pointer
2393 ** to sqlite3_free() is harmless.  After being freed, memory
2394 ** should neither be read nor written.  Even reading previously freed
2395 ** memory might result in a segmentation fault or other severe error.
2396 ** Memory corruption, a segmentation fault, or other severe error
2397 ** might result if sqlite3_free() is called with a non-NULL pointer that
2398 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
2399 **
2400 ** ^The sqlite3_realloc(X,N) interface attempts to resize a
2401 ** prior memory allocation X to be at least N bytes.
2402 ** ^If the X parameter to sqlite3_realloc(X,N)
2403 ** is a NULL pointer then its behavior is identical to calling
2404 ** sqlite3_malloc(N).
2405 ** ^If the N parameter to sqlite3_realloc(X,N) is zero or
2406 ** negative then the behavior is exactly the same as calling
2407 ** sqlite3_free(X).
2408 ** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
2409 ** of at least N bytes in size or NULL if insufficient memory is available.
2410 ** ^If M is the size of the prior allocation, then min(N,M) bytes
2411 ** of the prior allocation are copied into the beginning of buffer returned
2412 ** by sqlite3_realloc(X,N) and the prior allocation is freed.
2413 ** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
2414 ** prior allocation is not freed.
2415 **
2416 ** ^The sqlite3_realloc64(X,N) interfaces works the same as
2417 ** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
2418 ** of a 32-bit signed integer.
2419 **
2420 ** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
2421 ** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
2422 ** sqlite3_msize(X) returns the size of that memory allocation in bytes.
2423 ** ^The value returned by sqlite3_msize(X) might be larger than the number
2424 ** of bytes requested when X was allocated.  ^If X is a NULL pointer then
2425 ** sqlite3_msize(X) returns zero.  If X points to something that is not
2426 ** the beginning of memory allocation, or if it points to a formerly
2427 ** valid memory allocation that has now been freed, then the behavior
2428 ** of sqlite3_msize(X) is undefined and possibly harmful.
2429 **
2430 ** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
2431 ** sqlite3_malloc64(), and sqlite3_realloc64()
2432 ** is always aligned to at least an 8 byte boundary, or to a
2433 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
2434 ** option is used.
2435 **
2436 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
2437 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
2438 ** implementation of these routines to be omitted.  That capability
2439 ** is no longer provided.  Only built-in memory allocators can be used.
2440 **
2441 ** Prior to SQLite version 3.7.10, the Windows OS interface layer called
2442 ** the system malloc() and free() directly when converting
2443 ** filenames between the UTF-8 encoding used by SQLite
2444 ** and whatever filename encoding is used by the particular Windows
2445 ** installation.  Memory allocation errors were detected, but
2446 ** they were reported back as [SQLITE_CANTOPEN] or
2447 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
2448 **
2449 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
2450 ** must be either NULL or else pointers obtained from a prior
2451 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
2452 ** not yet been released.
2453 **
2454 ** The application must not read or write any part of
2455 ** a block of memory after it has been released using
2456 ** [sqlite3_free()] or [sqlite3_realloc()].
2457 */
2458 SQLITE_API void *SQLITE_STDCALL sqlite3_malloc(int);
2459 SQLITE_API void *SQLITE_STDCALL sqlite3_malloc64(sqlite3_uint64);
2460 SQLITE_API void *SQLITE_STDCALL sqlite3_realloc(void*, int);
2461 SQLITE_API void *SQLITE_STDCALL sqlite3_realloc64(void*, sqlite3_uint64);
2462 SQLITE_API void SQLITE_STDCALL sqlite3_free(void*);
2463 SQLITE_API sqlite3_uint64 SQLITE_STDCALL sqlite3_msize(void*);
2464 
2465 /*
2466 ** CAPI3REF: Memory Allocator Statistics
2467 **
2468 ** SQLite provides these two interfaces for reporting on the status
2469 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
2470 ** routines, which form the built-in memory allocation subsystem.
2471 **
2472 ** ^The [sqlite3_memory_used()] routine returns the number of bytes
2473 ** of memory currently outstanding (malloced but not freed).
2474 ** ^The [sqlite3_memory_highwater()] routine returns the maximum
2475 ** value of [sqlite3_memory_used()] since the high-water mark
2476 ** was last reset.  ^The values returned by [sqlite3_memory_used()] and
2477 ** [sqlite3_memory_highwater()] include any overhead
2478 ** added by SQLite in its implementation of [sqlite3_malloc()],
2479 ** but not overhead added by the any underlying system library
2480 ** routines that [sqlite3_malloc()] may call.
2481 **
2482 ** ^The memory high-water mark is reset to the current value of
2483 ** [sqlite3_memory_used()] if and only if the parameter to
2484 ** [sqlite3_memory_highwater()] is true.  ^The value returned
2485 ** by [sqlite3_memory_highwater(1)] is the high-water mark
2486 ** prior to the reset.
2487 */
2488 SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_memory_used(void);
2489 SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_memory_highwater(int resetFlag);
2490 
2491 /*
2492 ** CAPI3REF: Pseudo-Random Number Generator
2493 **
2494 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
2495 ** select random [ROWID | ROWIDs] when inserting new records into a table that
2496 ** already uses the largest possible [ROWID].  The PRNG is also used for
2497 ** the build-in random() and randomblob() SQL functions.  This interface allows
2498 ** applications to access the same PRNG for other purposes.
2499 **
2500 ** ^A call to this routine stores N bytes of randomness into buffer P.
2501 ** ^The P parameter can be a NULL pointer.
2502 **
2503 ** ^If this routine has not been previously called or if the previous
2504 ** call had N less than one or a NULL pointer for P, then the PRNG is
2505 ** seeded using randomness obtained from the xRandomness method of
2506 ** the default [sqlite3_vfs] object.
2507 ** ^If the previous call to this routine had an N of 1 or more and a
2508 ** non-NULL P then the pseudo-randomness is generated
2509 ** internally and without recourse to the [sqlite3_vfs] xRandomness
2510 ** method.
2511 */
2512 SQLITE_API void SQLITE_STDCALL sqlite3_randomness(int N, void *P);
2513 
2514 /*
2515 ** CAPI3REF: Compile-Time Authorization Callbacks
2516 ** METHOD: sqlite3
2517 **
2518 ** ^This routine registers an authorizer callback with a particular
2519 ** [database connection], supplied in the first argument.
2520 ** ^The authorizer callback is invoked as SQL statements are being compiled
2521 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
2522 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()].  ^At various
2523 ** points during the compilation process, as logic is being created
2524 ** to perform various actions, the authorizer callback is invoked to
2525 ** see if those actions are allowed.  ^The authorizer callback should
2526 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
2527 ** specific action but allow the SQL statement to continue to be
2528 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
2529 ** rejected with an error.  ^If the authorizer callback returns
2530 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
2531 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
2532 ** the authorizer will fail with an error message.
2533 **
2534 ** When the callback returns [SQLITE_OK], that means the operation
2535 ** requested is ok.  ^When the callback returns [SQLITE_DENY], the
2536 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
2537 ** authorizer will fail with an error message explaining that
2538 ** access is denied.
2539 **
2540 ** ^The first parameter to the authorizer callback is a copy of the third
2541 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
2542 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
2543 ** the particular action to be authorized. ^The third through sixth parameters
2544 ** to the callback are zero-terminated strings that contain additional
2545 ** details about the action to be authorized.
2546 **
2547 ** ^If the action code is [SQLITE_READ]
2548 ** and the callback returns [SQLITE_IGNORE] then the
2549 ** [prepared statement] statement is constructed to substitute
2550 ** a NULL value in place of the table column that would have
2551 ** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
2552 ** return can be used to deny an untrusted user access to individual
2553 ** columns of a table.
2554 ** ^If the action code is [SQLITE_DELETE] and the callback returns
2555 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
2556 ** [truncate optimization] is disabled and all rows are deleted individually.
2557 **
2558 ** An authorizer is used when [sqlite3_prepare | preparing]
2559 ** SQL statements from an untrusted source, to ensure that the SQL statements
2560 ** do not try to access data they are not allowed to see, or that they do not
2561 ** try to execute malicious statements that damage the database.  For
2562 ** example, an application may allow a user to enter arbitrary
2563 ** SQL queries for evaluation by a database.  But the application does
2564 ** not want the user to be able to make arbitrary changes to the
2565 ** database.  An authorizer could then be put in place while the
2566 ** user-entered SQL is being [sqlite3_prepare | prepared] that
2567 ** disallows everything except [SELECT] statements.
2568 **
2569 ** Applications that need to process SQL from untrusted sources
2570 ** might also consider lowering resource limits using [sqlite3_limit()]
2571 ** and limiting database size using the [max_page_count] [PRAGMA]
2572 ** in addition to using an authorizer.
2573 **
2574 ** ^(Only a single authorizer can be in place on a database connection
2575 ** at a time.  Each call to sqlite3_set_authorizer overrides the
2576 ** previous call.)^  ^Disable the authorizer by installing a NULL callback.
2577 ** The authorizer is disabled by default.
2578 **
2579 ** The authorizer callback must not do anything that will modify
2580 ** the database connection that invoked the authorizer callback.
2581 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2582 ** database connections for the meaning of "modify" in this paragraph.
2583 **
2584 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
2585 ** statement might be re-prepared during [sqlite3_step()] due to a
2586 ** schema change.  Hence, the application should ensure that the
2587 ** correct authorizer callback remains in place during the [sqlite3_step()].
2588 **
2589 ** ^Note that the authorizer callback is invoked only during
2590 ** [sqlite3_prepare()] or its variants.  Authorization is not
2591 ** performed during statement evaluation in [sqlite3_step()], unless
2592 ** as stated in the previous paragraph, sqlite3_step() invokes
2593 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
2594 */
2595 SQLITE_API int SQLITE_STDCALL sqlite3_set_authorizer(
2596   sqlite3*,
2597   int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
2598   void *pUserData
2599 );
2600 
2601 /*
2602 ** CAPI3REF: Authorizer Return Codes
2603 **
2604 ** The [sqlite3_set_authorizer | authorizer callback function] must
2605 ** return either [SQLITE_OK] or one of these two constants in order
2606 ** to signal SQLite whether or not the action is permitted.  See the
2607 ** [sqlite3_set_authorizer | authorizer documentation] for additional
2608 ** information.
2609 **
2610 ** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
2611 ** returned from the [sqlite3_vtab_on_conflict()] interface.
2612 */
2613 #define SQLITE_DENY   1   /* Abort the SQL statement with an error */
2614 #define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
2615 
2616 /*
2617 ** CAPI3REF: Authorizer Action Codes
2618 **
2619 ** The [sqlite3_set_authorizer()] interface registers a callback function
2620 ** that is invoked to authorize certain SQL statement actions.  The
2621 ** second parameter to the callback is an integer code that specifies
2622 ** what action is being authorized.  These are the integer action codes that
2623 ** the authorizer callback may be passed.
2624 **
2625 ** These action code values signify what kind of operation is to be
2626 ** authorized.  The 3rd and 4th parameters to the authorization
2627 ** callback function will be parameters or NULL depending on which of these
2628 ** codes is used as the second parameter.  ^(The 5th parameter to the
2629 ** authorizer callback is the name of the database ("main", "temp",
2630 ** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
2631 ** is the name of the inner-most trigger or view that is responsible for
2632 ** the access attempt or NULL if this access attempt is directly from
2633 ** top-level SQL code.
2634 */
2635 /******************************************* 3rd ************ 4th ***********/
2636 #define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
2637 #define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
2638 #define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
2639 #define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
2640 #define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
2641 #define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
2642 #define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
2643 #define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
2644 #define SQLITE_DELETE                9   /* Table Name      NULL            */
2645 #define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
2646 #define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
2647 #define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
2648 #define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
2649 #define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
2650 #define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
2651 #define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
2652 #define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
2653 #define SQLITE_INSERT               18   /* Table Name      NULL            */
2654 #define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
2655 #define SQLITE_READ                 20   /* Table Name      Column Name     */
2656 #define SQLITE_SELECT               21   /* NULL            NULL            */
2657 #define SQLITE_TRANSACTION          22   /* Operation       NULL            */
2658 #define SQLITE_UPDATE               23   /* Table Name      Column Name     */
2659 #define SQLITE_ATTACH               24   /* Filename        NULL            */
2660 #define SQLITE_DETACH               25   /* Database Name   NULL            */
2661 #define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
2662 #define SQLITE_REINDEX              27   /* Index Name      NULL            */
2663 #define SQLITE_ANALYZE              28   /* Table Name      NULL            */
2664 #define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
2665 #define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
2666 #define SQLITE_FUNCTION             31   /* NULL            Function Name   */
2667 #define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
2668 #define SQLITE_COPY                  0   /* No longer used */
2669 #define SQLITE_RECURSIVE            33   /* NULL            NULL            */
2670 
2671 /*
2672 ** CAPI3REF: Tracing And Profiling Functions
2673 ** METHOD: sqlite3
2674 **
2675 ** These routines register callback functions that can be used for
2676 ** tracing and profiling the execution of SQL statements.
2677 **
2678 ** ^The callback function registered by sqlite3_trace() is invoked at
2679 ** various times when an SQL statement is being run by [sqlite3_step()].
2680 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
2681 ** SQL statement text as the statement first begins executing.
2682 ** ^(Additional sqlite3_trace() callbacks might occur
2683 ** as each triggered subprogram is entered.  The callbacks for triggers
2684 ** contain a UTF-8 SQL comment that identifies the trigger.)^
2685 **
2686 ** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
2687 ** the length of [bound parameter] expansion in the output of sqlite3_trace().
2688 **
2689 ** ^The callback function registered by sqlite3_profile() is invoked
2690 ** as each SQL statement finishes.  ^The profile callback contains
2691 ** the original statement text and an estimate of wall-clock time
2692 ** of how long that statement took to run.  ^The profile callback
2693 ** time is in units of nanoseconds, however the current implementation
2694 ** is only capable of millisecond resolution so the six least significant
2695 ** digits in the time are meaningless.  Future versions of SQLite
2696 ** might provide greater resolution on the profiler callback.  The
2697 ** sqlite3_profile() function is considered experimental and is
2698 ** subject to change in future versions of SQLite.
2699 */
2700 SQLITE_API void *SQLITE_STDCALL sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
2701 SQLITE_API SQLITE_EXPERIMENTAL void *SQLITE_STDCALL sqlite3_profile(sqlite3*,
2702    void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
2703 
2704 /*
2705 ** CAPI3REF: Query Progress Callbacks
2706 ** METHOD: sqlite3
2707 **
2708 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
2709 ** function X to be invoked periodically during long running calls to
2710 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
2711 ** database connection D.  An example use for this
2712 ** interface is to keep a GUI updated during a large query.
2713 **
2714 ** ^The parameter P is passed through as the only parameter to the
2715 ** callback function X.  ^The parameter N is the approximate number of
2716 ** [virtual machine instructions] that are evaluated between successive
2717 ** invocations of the callback X.  ^If N is less than one then the progress
2718 ** handler is disabled.
2719 **
2720 ** ^Only a single progress handler may be defined at one time per
2721 ** [database connection]; setting a new progress handler cancels the
2722 ** old one.  ^Setting parameter X to NULL disables the progress handler.
2723 ** ^The progress handler is also disabled by setting N to a value less
2724 ** than 1.
2725 **
2726 ** ^If the progress callback returns non-zero, the operation is
2727 ** interrupted.  This feature can be used to implement a
2728 ** "Cancel" button on a GUI progress dialog box.
2729 **
2730 ** The progress handler callback must not do anything that will modify
2731 ** the database connection that invoked the progress handler.
2732 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
2733 ** database connections for the meaning of "modify" in this paragraph.
2734 **
2735 */
2736 SQLITE_API void SQLITE_STDCALL sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
2737 
2738 /*
2739 ** CAPI3REF: Opening A New Database Connection
2740 ** CONSTRUCTOR: sqlite3
2741 **
2742 ** ^These routines open an SQLite database file as specified by the
2743 ** filename argument. ^The filename argument is interpreted as UTF-8 for
2744 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
2745 ** order for sqlite3_open16(). ^(A [database connection] handle is usually
2746 ** returned in *ppDb, even if an error occurs.  The only exception is that
2747 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
2748 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
2749 ** object.)^ ^(If the database is opened (and/or created) successfully, then
2750 ** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
2751 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
2752 ** an English language description of the error following a failure of any
2753 ** of the sqlite3_open() routines.
2754 **
2755 ** ^The default encoding will be UTF-8 for databases created using
2756 ** sqlite3_open() or sqlite3_open_v2().  ^The default encoding for databases
2757 ** created using sqlite3_open16() will be UTF-16 in the native byte order.
2758 **
2759 ** Whether or not an error occurs when it is opened, resources
2760 ** associated with the [database connection] handle should be released by
2761 ** passing it to [sqlite3_close()] when it is no longer required.
2762 **
2763 ** The sqlite3_open_v2() interface works like sqlite3_open()
2764 ** except that it accepts two additional parameters for additional control
2765 ** over the new database connection.  ^(The flags parameter to
2766 ** sqlite3_open_v2() can take one of
2767 ** the following three values, optionally combined with the
2768 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
2769 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
2770 **
2771 ** <dl>
2772 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
2773 ** <dd>The database is opened in read-only mode.  If the database does not
2774 ** already exist, an error is returned.</dd>)^
2775 **
2776 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
2777 ** <dd>The database is opened for reading and writing if possible, or reading
2778 ** only if the file is write protected by the operating system.  In either
2779 ** case the database must already exist, otherwise an error is returned.</dd>)^
2780 **
2781 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
2782 ** <dd>The database is opened for reading and writing, and is created if
2783 ** it does not already exist. This is the behavior that is always used for
2784 ** sqlite3_open() and sqlite3_open16().</dd>)^
2785 ** </dl>
2786 **
2787 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
2788 ** combinations shown above optionally combined with other
2789 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
2790 ** then the behavior is undefined.
2791 **
2792 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
2793 ** opens in the multi-thread [threading mode] as long as the single-thread
2794 ** mode has not been set at compile-time or start-time.  ^If the
2795 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
2796 ** in the serialized [threading mode] unless single-thread was
2797 ** previously selected at compile-time or start-time.
2798 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
2799 ** eligible to use [shared cache mode], regardless of whether or not shared
2800 ** cache is enabled using [sqlite3_enable_shared_cache()].  ^The
2801 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
2802 ** participate in [shared cache mode] even if it is enabled.
2803 **
2804 ** ^The fourth parameter to sqlite3_open_v2() is the name of the
2805 ** [sqlite3_vfs] object that defines the operating system interface that
2806 ** the new database connection should use.  ^If the fourth parameter is
2807 ** a NULL pointer then the default [sqlite3_vfs] object is used.
2808 **
2809 ** ^If the filename is ":memory:", then a private, temporary in-memory database
2810 ** is created for the connection.  ^This in-memory database will vanish when
2811 ** the database connection is closed.  Future versions of SQLite might
2812 ** make use of additional special filenames that begin with the ":" character.
2813 ** It is recommended that when a database filename actually does begin with
2814 ** a ":" character you should prefix the filename with a pathname such as
2815 ** "./" to avoid ambiguity.
2816 **
2817 ** ^If the filename is an empty string, then a private, temporary
2818 ** on-disk database will be created.  ^This private database will be
2819 ** automatically deleted as soon as the database connection is closed.
2820 **
2821 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
2822 **
2823 ** ^If [URI filename] interpretation is enabled, and the filename argument
2824 ** begins with "file:", then the filename is interpreted as a URI. ^URI
2825 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
2826 ** set in the fourth argument to sqlite3_open_v2(), or if it has
2827 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
2828 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
2829 ** As of SQLite version 3.7.7, URI filename interpretation is turned off
2830 ** by default, but future releases of SQLite might enable URI filename
2831 ** interpretation by default.  See "[URI filenames]" for additional
2832 ** information.
2833 **
2834 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
2835 ** authority, then it must be either an empty string or the string
2836 ** "localhost". ^If the authority is not an empty string or "localhost", an
2837 ** error is returned to the caller. ^The fragment component of a URI, if
2838 ** present, is ignored.
2839 **
2840 ** ^SQLite uses the path component of the URI as the name of the disk file
2841 ** which contains the database. ^If the path begins with a '/' character,
2842 ** then it is interpreted as an absolute path. ^If the path does not begin
2843 ** with a '/' (meaning that the authority section is omitted from the URI)
2844 ** then the path is interpreted as a relative path.
2845 ** ^(On windows, the first component of an absolute path
2846 ** is a drive specification (e.g. "C:").)^
2847 **
2848 ** [[core URI query parameters]]
2849 ** The query component of a URI may contain parameters that are interpreted
2850 ** either by SQLite itself, or by a [VFS | custom VFS implementation].
2851 ** SQLite and its built-in [VFSes] interpret the
2852 ** following query parameters:
2853 **
2854 ** <ul>
2855 **   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
2856 **     a VFS object that provides the operating system interface that should
2857 **     be used to access the database file on disk. ^If this option is set to
2858 **     an empty string the default VFS object is used. ^Specifying an unknown
2859 **     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
2860 **     present, then the VFS specified by the option takes precedence over
2861 **     the value passed as the fourth parameter to sqlite3_open_v2().
2862 **
2863 **   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
2864 **     "rwc", or "memory". Attempting to set it to any other value is
2865 **     an error)^.
2866 **     ^If "ro" is specified, then the database is opened for read-only
2867 **     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
2868 **     third argument to sqlite3_open_v2(). ^If the mode option is set to
2869 **     "rw", then the database is opened for read-write (but not create)
2870 **     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
2871 **     been set. ^Value "rwc" is equivalent to setting both
2872 **     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE.  ^If the mode option is
2873 **     set to "memory" then a pure [in-memory database] that never reads
2874 **     or writes from disk is used. ^It is an error to specify a value for
2875 **     the mode parameter that is less restrictive than that specified by
2876 **     the flags passed in the third parameter to sqlite3_open_v2().
2877 **
2878 **   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
2879 **     "private". ^Setting it to "shared" is equivalent to setting the
2880 **     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
2881 **     sqlite3_open_v2(). ^Setting the cache parameter to "private" is
2882 **     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
2883 **     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
2884 **     a URI filename, its value overrides any behavior requested by setting
2885 **     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
2886 **
2887 **  <li> <b>psow</b>: ^The psow parameter indicates whether or not the
2888 **     [powersafe overwrite] property does or does not apply to the
2889 **     storage media on which the database file resides.
2890 **
2891 **  <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
2892 **     which if set disables file locking in rollback journal modes.  This
2893 **     is useful for accessing a database on a filesystem that does not
2894 **     support locking.  Caution:  Database corruption might result if two
2895 **     or more processes write to the same database and any one of those
2896 **     processes uses nolock=1.
2897 **
2898 **  <li> <b>immutable</b>: ^The immutable parameter is a boolean query
2899 **     parameter that indicates that the database file is stored on
2900 **     read-only media.  ^When immutable is set, SQLite assumes that the
2901 **     database file cannot be changed, even by a process with higher
2902 **     privilege, and so the database is opened read-only and all locking
2903 **     and change detection is disabled.  Caution: Setting the immutable
2904 **     property on a database file that does in fact change can result
2905 **     in incorrect query results and/or [SQLITE_CORRUPT] errors.
2906 **     See also: [SQLITE_IOCAP_IMMUTABLE].
2907 **
2908 ** </ul>
2909 **
2910 ** ^Specifying an unknown parameter in the query component of a URI is not an
2911 ** error.  Future versions of SQLite might understand additional query
2912 ** parameters.  See "[query parameters with special meaning to SQLite]" for
2913 ** additional information.
2914 **
2915 ** [[URI filename examples]] <h3>URI filename examples</h3>
2916 **
2917 ** <table border="1" align=center cellpadding=5>
2918 ** <tr><th> URI filenames <th> Results
2919 ** <tr><td> file:data.db <td>
2920 **          Open the file "data.db" in the current directory.
2921 ** <tr><td> file:/home/fred/data.db<br>
2922 **          file:///home/fred/data.db <br>
2923 **          file://localhost/home/fred/data.db <br> <td>
2924 **          Open the database file "/home/fred/data.db".
2925 ** <tr><td> file://darkstar/home/fred/data.db <td>
2926 **          An error. "darkstar" is not a recognized authority.
2927 ** <tr><td style="white-space:nowrap">
2928 **          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
2929 **     <td> Windows only: Open the file "data.db" on fred's desktop on drive
2930 **          C:. Note that the %20 escaping in this example is not strictly
2931 **          necessary - space characters can be used literally
2932 **          in URI filenames.
2933 ** <tr><td> file:data.db?mode=ro&cache=private <td>
2934 **          Open file "data.db" in the current directory for read-only access.
2935 **          Regardless of whether or not shared-cache mode is enabled by
2936 **          default, use a private cache.
2937 ** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
2938 **          Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
2939 **          that uses dot-files in place of posix advisory locking.
2940 ** <tr><td> file:data.db?mode=readonly <td>
2941 **          An error. "readonly" is not a valid option for the "mode" parameter.
2942 ** </table>
2943 **
2944 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
2945 ** query components of a URI. A hexadecimal escape sequence consists of a
2946 ** percent sign - "%" - followed by exactly two hexadecimal digits
2947 ** specifying an octet value. ^Before the path or query components of a
2948 ** URI filename are interpreted, they are encoded using UTF-8 and all
2949 ** hexadecimal escape sequences replaced by a single byte containing the
2950 ** corresponding octet. If this process generates an invalid UTF-8 encoding,
2951 ** the results are undefined.
2952 **
2953 ** <b>Note to Windows users:</b>  The encoding used for the filename argument
2954 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
2955 ** codepage is currently defined.  Filenames containing international
2956 ** characters must be converted to UTF-8 prior to passing them into
2957 ** sqlite3_open() or sqlite3_open_v2().
2958 **
2959 ** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
2960 ** prior to calling sqlite3_open() or sqlite3_open_v2().  Otherwise, various
2961 ** features that require the use of temporary files may fail.
2962 **
2963 ** See also: [sqlite3_temp_directory]
2964 */
2965 SQLITE_API int SQLITE_STDCALL sqlite3_open(
2966   const char *filename,   /* Database filename (UTF-8) */
2967   sqlite3 **ppDb          /* OUT: SQLite db handle */
2968 );
2969 SQLITE_API int SQLITE_STDCALL sqlite3_open16(
2970   const void *filename,   /* Database filename (UTF-16) */
2971   sqlite3 **ppDb          /* OUT: SQLite db handle */
2972 );
2973 SQLITE_API int SQLITE_STDCALL sqlite3_open_v2(
2974   const char *filename,   /* Database filename (UTF-8) */
2975   sqlite3 **ppDb,         /* OUT: SQLite db handle */
2976   int flags,              /* Flags */
2977   const char *zVfs        /* Name of VFS module to use */
2978 );
2979 
2980 /*
2981 ** CAPI3REF: Obtain Values For URI Parameters
2982 **
2983 ** These are utility routines, useful to VFS implementations, that check
2984 ** to see if a database file was a URI that contained a specific query
2985 ** parameter, and if so obtains the value of that query parameter.
2986 **
2987 ** If F is the database filename pointer passed into the xOpen() method of
2988 ** a VFS implementation when the flags parameter to xOpen() has one or
2989 ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
2990 ** P is the name of the query parameter, then
2991 ** sqlite3_uri_parameter(F,P) returns the value of the P
2992 ** parameter if it exists or a NULL pointer if P does not appear as a
2993 ** query parameter on F.  If P is a query parameter of F
2994 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns
2995 ** a pointer to an empty string.
2996 **
2997 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
2998 ** parameter and returns true (1) or false (0) according to the value
2999 ** of P.  The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
3000 ** value of query parameter P is one of "yes", "true", or "on" in any
3001 ** case or if the value begins with a non-zero number.  The
3002 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
3003 ** query parameter P is one of "no", "false", or "off" in any case or
3004 ** if the value begins with a numeric zero.  If P is not a query
3005 ** parameter on F or if the value of P is does not match any of the
3006 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
3007 **
3008 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
3009 ** 64-bit signed integer and returns that integer, or D if P does not
3010 ** exist.  If the value of P is something other than an integer, then
3011 ** zero is returned.
3012 **
3013 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
3014 ** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
3015 ** is not a database file pathname pointer that SQLite passed into the xOpen
3016 ** VFS method, then the behavior of this routine is undefined and probably
3017 ** undesirable.
3018 */
3019 SQLITE_API const char *SQLITE_STDCALL sqlite3_uri_parameter(const char *zFilename, const char *zParam);
3020 SQLITE_API int SQLITE_STDCALL sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
3021 SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
3022 
3023 
3024 /*
3025 ** CAPI3REF: Error Codes And Messages
3026 ** METHOD: sqlite3
3027 **
3028 ** ^If the most recent sqlite3_* API call associated with
3029 ** [database connection] D failed, then the sqlite3_errcode(D) interface
3030 ** returns the numeric [result code] or [extended result code] for that
3031 ** API call.
3032 ** If the most recent API call was successful,
3033 ** then the return value from sqlite3_errcode() is undefined.
3034 ** ^The sqlite3_extended_errcode()
3035 ** interface is the same except that it always returns the
3036 ** [extended result code] even when extended result codes are
3037 ** disabled.
3038 **
3039 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
3040 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
3041 ** ^(Memory to hold the error message string is managed internally.
3042 ** The application does not need to worry about freeing the result.
3043 ** However, the error string might be overwritten or deallocated by
3044 ** subsequent calls to other SQLite interface functions.)^
3045 **
3046 ** ^The sqlite3_errstr() interface returns the English-language text
3047 ** that describes the [result code], as UTF-8.
3048 ** ^(Memory to hold the error message string is managed internally
3049 ** and must not be freed by the application)^.
3050 **
3051 ** When the serialized [threading mode] is in use, it might be the
3052 ** case that a second error occurs on a separate thread in between
3053 ** the time of the first error and the call to these interfaces.
3054 ** When that happens, the second error will be reported since these
3055 ** interfaces always report the most recent result.  To avoid
3056 ** this, each thread can obtain exclusive use of the [database connection] D
3057 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
3058 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
3059 ** all calls to the interfaces listed here are completed.
3060 **
3061 ** If an interface fails with SQLITE_MISUSE, that means the interface
3062 ** was invoked incorrectly by the application.  In that case, the
3063 ** error code and message may or may not be set.
3064 */
3065 SQLITE_API int SQLITE_STDCALL sqlite3_errcode(sqlite3 *db);
3066 SQLITE_API int SQLITE_STDCALL sqlite3_extended_errcode(sqlite3 *db);
3067 SQLITE_API const char *SQLITE_STDCALL sqlite3_errmsg(sqlite3*);
3068 SQLITE_API const void *SQLITE_STDCALL sqlite3_errmsg16(sqlite3*);
3069 SQLITE_API const char *SQLITE_STDCALL sqlite3_errstr(int);
3070 
3071 /*
3072 ** CAPI3REF: Prepared Statement Object
3073 ** KEYWORDS: {prepared statement} {prepared statements}
3074 **
3075 ** An instance of this object represents a single SQL statement that
3076 ** has been compiled into binary form and is ready to be evaluated.
3077 **
3078 ** Think of each SQL statement as a separate computer program.  The
3079 ** original SQL text is source code.  A prepared statement object
3080 ** is the compiled object code.  All SQL must be converted into a
3081 ** prepared statement before it can be run.
3082 **
3083 ** The life-cycle of a prepared statement object usually goes like this:
3084 **
3085 ** <ol>
3086 ** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
3087 ** <li> Bind values to [parameters] using the sqlite3_bind_*()
3088 **      interfaces.
3089 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
3090 ** <li> Reset the prepared statement using [sqlite3_reset()] then go back
3091 **      to step 2.  Do this zero or more times.
3092 ** <li> Destroy the object using [sqlite3_finalize()].
3093 ** </ol>
3094 */
3095 typedef struct sqlite3_stmt sqlite3_stmt;
3096 
3097 /*
3098 ** CAPI3REF: Run-time Limits
3099 ** METHOD: sqlite3
3100 **
3101 ** ^(This interface allows the size of various constructs to be limited
3102 ** on a connection by connection basis.  The first parameter is the
3103 ** [database connection] whose limit is to be set or queried.  The
3104 ** second parameter is one of the [limit categories] that define a
3105 ** class of constructs to be size limited.  The third parameter is the
3106 ** new limit for that construct.)^
3107 **
3108 ** ^If the new limit is a negative number, the limit is unchanged.
3109 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
3110 ** [limits | hard upper bound]
3111 ** set at compile-time by a C preprocessor macro called
3112 ** [limits | SQLITE_MAX_<i>NAME</i>].
3113 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
3114 ** ^Attempts to increase a limit above its hard upper bound are
3115 ** silently truncated to the hard upper bound.
3116 **
3117 ** ^Regardless of whether or not the limit was changed, the
3118 ** [sqlite3_limit()] interface returns the prior value of the limit.
3119 ** ^Hence, to find the current value of a limit without changing it,
3120 ** simply invoke this interface with the third parameter set to -1.
3121 **
3122 ** Run-time limits are intended for use in applications that manage
3123 ** both their own internal database and also databases that are controlled
3124 ** by untrusted external sources.  An example application might be a
3125 ** web browser that has its own databases for storing history and
3126 ** separate databases controlled by JavaScript applications downloaded
3127 ** off the Internet.  The internal databases can be given the
3128 ** large, default limits.  Databases managed by external sources can
3129 ** be given much smaller limits designed to prevent a denial of service
3130 ** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
3131 ** interface to further control untrusted SQL.  The size of the database
3132 ** created by an untrusted script can be contained using the
3133 ** [max_page_count] [PRAGMA].
3134 **
3135 ** New run-time limit categories may be added in future releases.
3136 */
3137 SQLITE_API int SQLITE_STDCALL sqlite3_limit(sqlite3*, int id, int newVal);
3138 
3139 /*
3140 ** CAPI3REF: Run-Time Limit Categories
3141 ** KEYWORDS: {limit category} {*limit categories}
3142 **
3143 ** These constants define various performance limits
3144 ** that can be lowered at run-time using [sqlite3_limit()].
3145 ** The synopsis of the meanings of the various limits is shown below.
3146 ** Additional information is available at [limits | Limits in SQLite].
3147 **
3148 ** <dl>
3149 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
3150 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
3151 **
3152 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
3153 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
3154 **
3155 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
3156 ** <dd>The maximum number of columns in a table definition or in the
3157 ** result set of a [SELECT] or the maximum number of columns in an index
3158 ** or in an ORDER BY or GROUP BY clause.</dd>)^
3159 **
3160 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
3161 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
3162 **
3163 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
3164 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
3165 **
3166 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
3167 ** <dd>The maximum number of instructions in a virtual machine program
3168 ** used to implement an SQL statement.  This limit is not currently
3169 ** enforced, though that might be added in some future release of
3170 ** SQLite.</dd>)^
3171 **
3172 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
3173 ** <dd>The maximum number of arguments on a function.</dd>)^
3174 **
3175 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
3176 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
3177 **
3178 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
3179 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
3180 ** <dd>The maximum length of the pattern argument to the [LIKE] or
3181 ** [GLOB] operators.</dd>)^
3182 **
3183 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
3184 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
3185 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
3186 **
3187 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
3188 ** <dd>The maximum depth of recursion for triggers.</dd>)^
3189 **
3190 ** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
3191 ** <dd>The maximum number of auxiliary worker threads that a single
3192 ** [prepared statement] may start.</dd>)^
3193 ** </dl>
3194 */
3195 #define SQLITE_LIMIT_LENGTH                    0
3196 #define SQLITE_LIMIT_SQL_LENGTH                1
3197 #define SQLITE_LIMIT_COLUMN                    2
3198 #define SQLITE_LIMIT_EXPR_DEPTH                3
3199 #define SQLITE_LIMIT_COMPOUND_SELECT           4
3200 #define SQLITE_LIMIT_VDBE_OP                   5
3201 #define SQLITE_LIMIT_FUNCTION_ARG              6
3202 #define SQLITE_LIMIT_ATTACHED                  7
3203 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
3204 #define SQLITE_LIMIT_VARIABLE_NUMBER           9
3205 #define SQLITE_LIMIT_TRIGGER_DEPTH            10
3206 #define SQLITE_LIMIT_WORKER_THREADS           11
3207 
3208 /*
3209 ** CAPI3REF: Compiling An SQL Statement
3210 ** KEYWORDS: {SQL statement compiler}
3211 ** METHOD: sqlite3
3212 ** CONSTRUCTOR: sqlite3_stmt
3213 **
3214 ** To execute an SQL query, it must first be compiled into a byte-code
3215 ** program using one of these routines.
3216 **
3217 ** The first argument, "db", is a [database connection] obtained from a
3218 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
3219 ** [sqlite3_open16()].  The database connection must not have been closed.
3220 **
3221 ** The second argument, "zSql", is the statement to be compiled, encoded
3222 ** as either UTF-8 or UTF-16.  The sqlite3_prepare() and sqlite3_prepare_v2()
3223 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2()
3224 ** use UTF-16.
3225 **
3226 ** ^If the nByte argument is negative, then zSql is read up to the
3227 ** first zero terminator. ^If nByte is positive, then it is the
3228 ** number of bytes read from zSql.  ^If nByte is zero, then no prepared
3229 ** statement is generated.
3230 ** If the caller knows that the supplied string is nul-terminated, then
3231 ** there is a small performance advantage to passing an nByte parameter that
3232 ** is the number of bytes in the input string <i>including</i>
3233 ** the nul-terminator.
3234 **
3235 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
3236 ** past the end of the first SQL statement in zSql.  These routines only
3237 ** compile the first statement in zSql, so *pzTail is left pointing to
3238 ** what remains uncompiled.
3239 **
3240 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
3241 ** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
3242 ** to NULL.  ^If the input text contains no SQL (if the input is an empty
3243 ** string or a comment) then *ppStmt is set to NULL.
3244 ** The calling procedure is responsible for deleting the compiled
3245 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
3246 ** ppStmt may not be NULL.
3247 **
3248 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
3249 ** otherwise an [error code] is returned.
3250 **
3251 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are
3252 ** recommended for all new programs. The two older interfaces are retained
3253 ** for backwards compatibility, but their use is discouraged.
3254 ** ^In the "v2" interfaces, the prepared statement
3255 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
3256 ** original SQL text. This causes the [sqlite3_step()] interface to
3257 ** behave differently in three ways:
3258 **
3259 ** <ol>
3260 ** <li>
3261 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
3262 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
3263 ** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
3264 ** retries will occur before sqlite3_step() gives up and returns an error.
3265 ** </li>
3266 **
3267 ** <li>
3268 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
3269 ** [error codes] or [extended error codes].  ^The legacy behavior was that
3270 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
3271 ** and the application would have to make a second call to [sqlite3_reset()]
3272 ** in order to find the underlying cause of the problem. With the "v2" prepare
3273 ** interfaces, the underlying reason for the error is returned immediately.
3274 ** </li>
3275 **
3276 ** <li>
3277 ** ^If the specific value bound to [parameter | host parameter] in the
3278 ** WHERE clause might influence the choice of query plan for a statement,
3279 ** then the statement will be automatically recompiled, as if there had been
3280 ** a schema change, on the first  [sqlite3_step()] call following any change
3281 ** to the [sqlite3_bind_text | bindings] of that [parameter].
3282 ** ^The specific value of WHERE-clause [parameter] might influence the
3283 ** choice of query plan if the parameter is the left-hand side of a [LIKE]
3284 ** or [GLOB] operator or if the parameter is compared to an indexed column
3285 ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
3286 ** </li>
3287 ** </ol>
3288 */
3289 SQLITE_API int SQLITE_STDCALL sqlite3_prepare(
3290   sqlite3 *db,            /* Database handle */
3291   const char *zSql,       /* SQL statement, UTF-8 encoded */
3292   int nByte,              /* Maximum length of zSql in bytes. */
3293   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3294   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
3295 );
3296 SQLITE_API int SQLITE_STDCALL sqlite3_prepare_v2(
3297   sqlite3 *db,            /* Database handle */
3298   const char *zSql,       /* SQL statement, UTF-8 encoded */
3299   int nByte,              /* Maximum length of zSql in bytes. */
3300   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3301   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
3302 );
3303 SQLITE_API int SQLITE_STDCALL sqlite3_prepare16(
3304   sqlite3 *db,            /* Database handle */
3305   const void *zSql,       /* SQL statement, UTF-16 encoded */
3306   int nByte,              /* Maximum length of zSql in bytes. */
3307   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3308   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
3309 );
3310 SQLITE_API int SQLITE_STDCALL sqlite3_prepare16_v2(
3311   sqlite3 *db,            /* Database handle */
3312   const void *zSql,       /* SQL statement, UTF-16 encoded */
3313   int nByte,              /* Maximum length of zSql in bytes. */
3314   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
3315   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
3316 );
3317 
3318 /*
3319 ** CAPI3REF: Retrieving Statement SQL
3320 ** METHOD: sqlite3_stmt
3321 **
3322 ** ^This interface can be used to retrieve a saved copy of the original
3323 ** SQL text used to create a [prepared statement] if that statement was
3324 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()].
3325 */
3326 SQLITE_API const char *SQLITE_STDCALL sqlite3_sql(sqlite3_stmt *pStmt);
3327 
3328 /*
3329 ** CAPI3REF: Determine If An SQL Statement Writes The Database
3330 ** METHOD: sqlite3_stmt
3331 **
3332 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
3333 ** and only if the [prepared statement] X makes no direct changes to
3334 ** the content of the database file.
3335 **
3336 ** Note that [application-defined SQL functions] or
3337 ** [virtual tables] might change the database indirectly as a side effect.
3338 ** ^(For example, if an application defines a function "eval()" that
3339 ** calls [sqlite3_exec()], then the following SQL statement would
3340 ** change the database file through side-effects:
3341 **
3342 ** <blockquote><pre>
3343 **    SELECT eval('DELETE FROM t1') FROM t2;
3344 ** </pre></blockquote>
3345 **
3346 ** But because the [SELECT] statement does not change the database file
3347 ** directly, sqlite3_stmt_readonly() would still return true.)^
3348 **
3349 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
3350 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
3351 ** since the statements themselves do not actually modify the database but
3352 ** rather they control the timing of when other statements modify the
3353 ** database.  ^The [ATTACH] and [DETACH] statements also cause
3354 ** sqlite3_stmt_readonly() to return true since, while those statements
3355 ** change the configuration of a database connection, they do not make
3356 ** changes to the content of the database files on disk.
3357 */
3358 SQLITE_API int SQLITE_STDCALL sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
3359 
3360 /*
3361 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset
3362 ** METHOD: sqlite3_stmt
3363 **
3364 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
3365 ** [prepared statement] S has been stepped at least once using
3366 ** [sqlite3_step(S)] but has not run to completion and/or has not
3367 ** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
3368 ** interface returns false if S is a NULL pointer.  If S is not a
3369 ** NULL pointer and is not a pointer to a valid [prepared statement]
3370 ** object, then the behavior is undefined and probably undesirable.
3371 **
3372 ** This interface can be used in combination [sqlite3_next_stmt()]
3373 ** to locate all prepared statements associated with a database
3374 ** connection that are in need of being reset.  This can be used,
3375 ** for example, in diagnostic routines to search for prepared
3376 ** statements that are holding a transaction open.
3377 */
3378 SQLITE_API int SQLITE_STDCALL sqlite3_stmt_busy(sqlite3_stmt*);
3379 
3380 /*
3381 ** CAPI3REF: Dynamically Typed Value Object
3382 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
3383 **
3384 ** SQLite uses the sqlite3_value object to represent all values
3385 ** that can be stored in a database table. SQLite uses dynamic typing
3386 ** for the values it stores.  ^Values stored in sqlite3_value objects
3387 ** can be integers, floating point values, strings, BLOBs, or NULL.
3388 **
3389 ** An sqlite3_value object may be either "protected" or "unprotected".
3390 ** Some interfaces require a protected sqlite3_value.  Other interfaces
3391 ** will accept either a protected or an unprotected sqlite3_value.
3392 ** Every interface that accepts sqlite3_value arguments specifies
3393 ** whether or not it requires a protected sqlite3_value.
3394 **
3395 ** The terms "protected" and "unprotected" refer to whether or not
3396 ** a mutex is held.  An internal mutex is held for a protected
3397 ** sqlite3_value object but no mutex is held for an unprotected
3398 ** sqlite3_value object.  If SQLite is compiled to be single-threaded
3399 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
3400 ** or if SQLite is run in one of reduced mutex modes
3401 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
3402 ** then there is no distinction between protected and unprotected
3403 ** sqlite3_value objects and they can be used interchangeably.  However,
3404 ** for maximum code portability it is recommended that applications
3405 ** still make the distinction between protected and unprotected
3406 ** sqlite3_value objects even when not strictly required.
3407 **
3408 ** ^The sqlite3_value objects that are passed as parameters into the
3409 ** implementation of [application-defined SQL functions] are protected.
3410 ** ^The sqlite3_value object returned by
3411 ** [sqlite3_column_value()] is unprotected.
3412 ** Unprotected sqlite3_value objects may only be used with
3413 ** [sqlite3_result_value()] and [sqlite3_bind_value()].
3414 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
3415 ** interfaces require protected sqlite3_value objects.
3416 */
3417 typedef struct Mem sqlite3_value;
3418 
3419 /*
3420 ** CAPI3REF: SQL Function Context Object
3421 **
3422 ** The context in which an SQL function executes is stored in an
3423 ** sqlite3_context object.  ^A pointer to an sqlite3_context object
3424 ** is always first parameter to [application-defined SQL functions].
3425 ** The application-defined SQL function implementation will pass this
3426 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
3427 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
3428 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
3429 ** and/or [sqlite3_set_auxdata()].
3430 */
3431 typedef struct sqlite3_context sqlite3_context;
3432 
3433 /*
3434 ** CAPI3REF: Binding Values To Prepared Statements
3435 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
3436 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
3437 ** METHOD: sqlite3_stmt
3438 **
3439 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
3440 ** literals may be replaced by a [parameter] that matches one of following
3441 ** templates:
3442 **
3443 ** <ul>
3444 ** <li>  ?
3445 ** <li>  ?NNN
3446 ** <li>  :VVV
3447 ** <li>  @VVV
3448 ** <li>  $VVV
3449 ** </ul>
3450 **
3451 ** In the templates above, NNN represents an integer literal,
3452 ** and VVV represents an alphanumeric identifier.)^  ^The values of these
3453 ** parameters (also called "host parameter names" or "SQL parameters")
3454 ** can be set using the sqlite3_bind_*() routines defined here.
3455 **
3456 ** ^The first argument to the sqlite3_bind_*() routines is always
3457 ** a pointer to the [sqlite3_stmt] object returned from
3458 ** [sqlite3_prepare_v2()] or its variants.
3459 **
3460 ** ^The second argument is the index of the SQL parameter to be set.
3461 ** ^The leftmost SQL parameter has an index of 1.  ^When the same named
3462 ** SQL parameter is used more than once, second and subsequent
3463 ** occurrences have the same index as the first occurrence.
3464 ** ^The index for named parameters can be looked up using the
3465 ** [sqlite3_bind_parameter_index()] API if desired.  ^The index
3466 ** for "?NNN" parameters is the value of NNN.
3467 ** ^The NNN value must be between 1 and the [sqlite3_limit()]
3468 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
3469 **
3470 ** ^The third argument is the value to bind to the parameter.
3471 ** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3472 ** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
3473 ** is ignored and the end result is the same as sqlite3_bind_null().
3474 **
3475 ** ^(In those routines that have a fourth argument, its value is the
3476 ** number of bytes in the parameter.  To be clear: the value is the
3477 ** number of <u>bytes</u> in the value, not the number of characters.)^
3478 ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
3479 ** is negative, then the length of the string is
3480 ** the number of bytes up to the first zero terminator.
3481 ** If the fourth parameter to sqlite3_bind_blob() is negative, then
3482 ** the behavior is undefined.
3483 ** If a non-negative fourth parameter is provided to sqlite3_bind_text()
3484 ** or sqlite3_bind_text16() or sqlite3_bind_text64() then
3485 ** that parameter must be the byte offset
3486 ** where the NUL terminator would occur assuming the string were NUL
3487 ** terminated.  If any NUL characters occur at byte offsets less than
3488 ** the value of the fourth parameter then the resulting string value will
3489 ** contain embedded NULs.  The result of expressions involving strings
3490 ** with embedded NULs is undefined.
3491 **
3492 ** ^The fifth argument to the BLOB and string binding interfaces
3493 ** is a destructor used to dispose of the BLOB or
3494 ** string after SQLite has finished with it.  ^The destructor is called
3495 ** to dispose of the BLOB or string even if the call to bind API fails.
3496 ** ^If the fifth argument is
3497 ** the special value [SQLITE_STATIC], then SQLite assumes that the
3498 ** information is in static, unmanaged space and does not need to be freed.
3499 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
3500 ** SQLite makes its own private copy of the data immediately, before
3501 ** the sqlite3_bind_*() routine returns.
3502 **
3503 ** ^The sixth argument to sqlite3_bind_text64() must be one of
3504 ** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
3505 ** to specify the encoding of the text in the third parameter.  If
3506 ** the sixth argument to sqlite3_bind_text64() is not one of the
3507 ** allowed values shown above, or if the text encoding is different
3508 ** from the encoding specified by the sixth parameter, then the behavior
3509 ** is undefined.
3510 **
3511 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
3512 ** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
3513 ** (just an integer to hold its size) while it is being processed.
3514 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
3515 ** content is later written using
3516 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
3517 ** ^A negative value for the zeroblob results in a zero-length BLOB.
3518 **
3519 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
3520 ** for the [prepared statement] or with a prepared statement for which
3521 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
3522 ** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
3523 ** routine is passed a [prepared statement] that has been finalized, the
3524 ** result is undefined and probably harmful.
3525 **
3526 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
3527 ** ^Unbound parameters are interpreted as NULL.
3528 **
3529 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
3530 ** [error code] if anything goes wrong.
3531 ** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
3532 ** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
3533 ** [SQLITE_MAX_LENGTH].
3534 ** ^[SQLITE_RANGE] is returned if the parameter
3535 ** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
3536 **
3537 ** See also: [sqlite3_bind_parameter_count()],
3538 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
3539 */
3540 SQLITE_API int SQLITE_STDCALL sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
3541 SQLITE_API int SQLITE_STDCALL sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
3542                         void(*)(void*));
3543 SQLITE_API int SQLITE_STDCALL sqlite3_bind_double(sqlite3_stmt*, int, double);
3544 SQLITE_API int SQLITE_STDCALL sqlite3_bind_int(sqlite3_stmt*, int, int);
3545 SQLITE_API int SQLITE_STDCALL sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
3546 SQLITE_API int SQLITE_STDCALL sqlite3_bind_null(sqlite3_stmt*, int);
3547 SQLITE_API int SQLITE_STDCALL sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
3548 SQLITE_API int SQLITE_STDCALL sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
3549 SQLITE_API int SQLITE_STDCALL sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
3550                          void(*)(void*), unsigned char encoding);
3551 SQLITE_API int SQLITE_STDCALL sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
3552 SQLITE_API int SQLITE_STDCALL sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
3553 
3554 /*
3555 ** CAPI3REF: Number Of SQL Parameters
3556 ** METHOD: sqlite3_stmt
3557 **
3558 ** ^This routine can be used to find the number of [SQL parameters]
3559 ** in a [prepared statement].  SQL parameters are tokens of the
3560 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
3561 ** placeholders for values that are [sqlite3_bind_blob | bound]
3562 ** to the parameters at a later time.
3563 **
3564 ** ^(This routine actually returns the index of the largest (rightmost)
3565 ** parameter. For all forms except ?NNN, this will correspond to the
3566 ** number of unique parameters.  If parameters of the ?NNN form are used,
3567 ** there may be gaps in the list.)^
3568 **
3569 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3570 ** [sqlite3_bind_parameter_name()], and
3571 ** [sqlite3_bind_parameter_index()].
3572 */
3573 SQLITE_API int SQLITE_STDCALL sqlite3_bind_parameter_count(sqlite3_stmt*);
3574 
3575 /*
3576 ** CAPI3REF: Name Of A Host Parameter
3577 ** METHOD: sqlite3_stmt
3578 **
3579 ** ^The sqlite3_bind_parameter_name(P,N) interface returns
3580 ** the name of the N-th [SQL parameter] in the [prepared statement] P.
3581 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
3582 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
3583 ** respectively.
3584 ** In other words, the initial ":" or "$" or "@" or "?"
3585 ** is included as part of the name.)^
3586 ** ^Parameters of the form "?" without a following integer have no name
3587 ** and are referred to as "nameless" or "anonymous parameters".
3588 **
3589 ** ^The first host parameter has an index of 1, not 0.
3590 **
3591 ** ^If the value N is out of range or if the N-th parameter is
3592 ** nameless, then NULL is returned.  ^The returned string is
3593 ** always in UTF-8 encoding even if the named parameter was
3594 ** originally specified as UTF-16 in [sqlite3_prepare16()] or
3595 ** [sqlite3_prepare16_v2()].
3596 **
3597 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3598 ** [sqlite3_bind_parameter_count()], and
3599 ** [sqlite3_bind_parameter_index()].
3600 */
3601 SQLITE_API const char *SQLITE_STDCALL sqlite3_bind_parameter_name(sqlite3_stmt*, int);
3602 
3603 /*
3604 ** CAPI3REF: Index Of A Parameter With A Given Name
3605 ** METHOD: sqlite3_stmt
3606 **
3607 ** ^Return the index of an SQL parameter given its name.  ^The
3608 ** index value returned is suitable for use as the second
3609 ** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
3610 ** is returned if no matching parameter is found.  ^The parameter
3611 ** name must be given in UTF-8 even if the original statement
3612 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()].
3613 **
3614 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
3615 ** [sqlite3_bind_parameter_count()], and
3616 ** [sqlite3_bind_parameter_index()].
3617 */
3618 SQLITE_API int SQLITE_STDCALL sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
3619 
3620 /*
3621 ** CAPI3REF: Reset All Bindings On A Prepared Statement
3622 ** METHOD: sqlite3_stmt
3623 **
3624 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
3625 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
3626 ** ^Use this routine to reset all host parameters to NULL.
3627 */
3628 SQLITE_API int SQLITE_STDCALL sqlite3_clear_bindings(sqlite3_stmt*);
3629 
3630 /*
3631 ** CAPI3REF: Number Of Columns In A Result Set
3632 ** METHOD: sqlite3_stmt
3633 **
3634 ** ^Return the number of columns in the result set returned by the
3635 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL
3636 ** statement that does not return data (for example an [UPDATE]).
3637 **
3638 ** See also: [sqlite3_data_count()]
3639 */
3640 SQLITE_API int SQLITE_STDCALL sqlite3_column_count(sqlite3_stmt *pStmt);
3641 
3642 /*
3643 ** CAPI3REF: Column Names In A Result Set
3644 ** METHOD: sqlite3_stmt
3645 **
3646 ** ^These routines return the name assigned to a particular column
3647 ** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
3648 ** interface returns a pointer to a zero-terminated UTF-8 string
3649 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
3650 ** UTF-16 string.  ^The first parameter is the [prepared statement]
3651 ** that implements the [SELECT] statement. ^The second parameter is the
3652 ** column number.  ^The leftmost column is number 0.
3653 **
3654 ** ^The returned string pointer is valid until either the [prepared statement]
3655 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
3656 ** reprepared by the first call to [sqlite3_step()] for a particular run
3657 ** or until the next call to
3658 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
3659 **
3660 ** ^If sqlite3_malloc() fails during the processing of either routine
3661 ** (for example during a conversion from UTF-8 to UTF-16) then a
3662 ** NULL pointer is returned.
3663 **
3664 ** ^The name of a result column is the value of the "AS" clause for
3665 ** that column, if there is an AS clause.  If there is no AS clause
3666 ** then the name of the column is unspecified and may change from
3667 ** one release of SQLite to the next.
3668 */
3669 SQLITE_API const char *SQLITE_STDCALL sqlite3_column_name(sqlite3_stmt*, int N);
3670 SQLITE_API const void *SQLITE_STDCALL sqlite3_column_name16(sqlite3_stmt*, int N);
3671 
3672 /*
3673 ** CAPI3REF: Source Of Data In A Query Result
3674 ** METHOD: sqlite3_stmt
3675 **
3676 ** ^These routines provide a means to determine the database, table, and
3677 ** table column that is the origin of a particular result column in
3678 ** [SELECT] statement.
3679 ** ^The name of the database or table or column can be returned as
3680 ** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
3681 ** the database name, the _table_ routines return the table name, and
3682 ** the origin_ routines return the column name.
3683 ** ^The returned string is valid until the [prepared statement] is destroyed
3684 ** using [sqlite3_finalize()] or until the statement is automatically
3685 ** reprepared by the first call to [sqlite3_step()] for a particular run
3686 ** or until the same information is requested
3687 ** again in a different encoding.
3688 **
3689 ** ^The names returned are the original un-aliased names of the
3690 ** database, table, and column.
3691 **
3692 ** ^The first argument to these interfaces is a [prepared statement].
3693 ** ^These functions return information about the Nth result column returned by
3694 ** the statement, where N is the second function argument.
3695 ** ^The left-most column is column 0 for these routines.
3696 **
3697 ** ^If the Nth column returned by the statement is an expression or
3698 ** subquery and is not a column value, then all of these functions return
3699 ** NULL.  ^These routine might also return NULL if a memory allocation error
3700 ** occurs.  ^Otherwise, they return the name of the attached database, table,
3701 ** or column that query result column was extracted from.
3702 **
3703 ** ^As with all other SQLite APIs, those whose names end with "16" return
3704 ** UTF-16 encoded strings and the other functions return UTF-8.
3705 **
3706 ** ^These APIs are only available if the library was compiled with the
3707 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
3708 **
3709 ** If two or more threads call one or more of these routines against the same
3710 ** prepared statement and column at the same time then the results are
3711 ** undefined.
3712 **
3713 ** If two or more threads call one or more
3714 ** [sqlite3_column_database_name | column metadata interfaces]
3715 ** for the same [prepared statement] and result column
3716 ** at the same time then the results are undefined.
3717 */
3718 SQLITE_API const char *SQLITE_STDCALL sqlite3_column_database_name(sqlite3_stmt*,int);
3719 SQLITE_API const void *SQLITE_STDCALL sqlite3_column_database_name16(sqlite3_stmt*,int);
3720 SQLITE_API const char *SQLITE_STDCALL sqlite3_column_table_name(sqlite3_stmt*,int);
3721 SQLITE_API const void *SQLITE_STDCALL sqlite3_column_table_name16(sqlite3_stmt*,int);
3722 SQLITE_API const char *SQLITE_STDCALL sqlite3_column_origin_name(sqlite3_stmt*,int);
3723 SQLITE_API const void *SQLITE_STDCALL sqlite3_column_origin_name16(sqlite3_stmt*,int);
3724 
3725 /*
3726 ** CAPI3REF: Declared Datatype Of A Query Result
3727 ** METHOD: sqlite3_stmt
3728 **
3729 ** ^(The first parameter is a [prepared statement].
3730 ** If this statement is a [SELECT] statement and the Nth column of the
3731 ** returned result set of that [SELECT] is a table column (not an
3732 ** expression or subquery) then the declared type of the table
3733 ** column is returned.)^  ^If the Nth column of the result set is an
3734 ** expression or subquery, then a NULL pointer is returned.
3735 ** ^The returned string is always UTF-8 encoded.
3736 **
3737 ** ^(For example, given the database schema:
3738 **
3739 ** CREATE TABLE t1(c1 VARIANT);
3740 **
3741 ** and the following statement to be compiled:
3742 **
3743 ** SELECT c1 + 1, c1 FROM t1;
3744 **
3745 ** this routine would return the string "VARIANT" for the second result
3746 ** column (i==1), and a NULL pointer for the first result column (i==0).)^
3747 **
3748 ** ^SQLite uses dynamic run-time typing.  ^So just because a column
3749 ** is declared to contain a particular type does not mean that the
3750 ** data stored in that column is of the declared type.  SQLite is
3751 ** strongly typed, but the typing is dynamic not static.  ^Type
3752 ** is associated with individual values, not with the containers
3753 ** used to hold those values.
3754 */
3755 SQLITE_API const char *SQLITE_STDCALL sqlite3_column_decltype(sqlite3_stmt*,int);
3756 SQLITE_API const void *SQLITE_STDCALL sqlite3_column_decltype16(sqlite3_stmt*,int);
3757 
3758 /*
3759 ** CAPI3REF: Evaluate An SQL Statement
3760 ** METHOD: sqlite3_stmt
3761 **
3762 ** After a [prepared statement] has been prepared using either
3763 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy
3764 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
3765 ** must be called one or more times to evaluate the statement.
3766 **
3767 ** The details of the behavior of the sqlite3_step() interface depend
3768 ** on whether the statement was prepared using the newer "v2" interface
3769 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy
3770 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
3771 ** new "v2" interface is recommended for new applications but the legacy
3772 ** interface will continue to be supported.
3773 **
3774 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
3775 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
3776 ** ^With the "v2" interface, any of the other [result codes] or
3777 ** [extended result codes] might be returned as well.
3778 **
3779 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
3780 ** database locks it needs to do its job.  ^If the statement is a [COMMIT]
3781 ** or occurs outside of an explicit transaction, then you can retry the
3782 ** statement.  If the statement is not a [COMMIT] and occurs within an
3783 ** explicit transaction then you should rollback the transaction before
3784 ** continuing.
3785 **
3786 ** ^[SQLITE_DONE] means that the statement has finished executing
3787 ** successfully.  sqlite3_step() should not be called again on this virtual
3788 ** machine without first calling [sqlite3_reset()] to reset the virtual
3789 ** machine back to its initial state.
3790 **
3791 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
3792 ** is returned each time a new row of data is ready for processing by the
3793 ** caller. The values may be accessed using the [column access functions].
3794 ** sqlite3_step() is called again to retrieve the next row of data.
3795 **
3796 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
3797 ** violation) has occurred.  sqlite3_step() should not be called again on
3798 ** the VM. More information may be found by calling [sqlite3_errmsg()].
3799 ** ^With the legacy interface, a more specific error code (for example,
3800 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
3801 ** can be obtained by calling [sqlite3_reset()] on the
3802 ** [prepared statement].  ^In the "v2" interface,
3803 ** the more specific error code is returned directly by sqlite3_step().
3804 **
3805 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
3806 ** Perhaps it was called on a [prepared statement] that has
3807 ** already been [sqlite3_finalize | finalized] or on one that had
3808 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
3809 ** be the case that the same database connection is being used by two or
3810 ** more threads at the same moment in time.
3811 **
3812 ** For all versions of SQLite up to and including 3.6.23.1, a call to
3813 ** [sqlite3_reset()] was required after sqlite3_step() returned anything
3814 ** other than [SQLITE_ROW] before any subsequent invocation of
3815 ** sqlite3_step().  Failure to reset the prepared statement using
3816 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
3817 ** sqlite3_step().  But after version 3.6.23.1, sqlite3_step() began
3818 ** calling [sqlite3_reset()] automatically in this circumstance rather
3819 ** than returning [SQLITE_MISUSE].  This is not considered a compatibility
3820 ** break because any application that ever receives an SQLITE_MISUSE error
3821 ** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
3822 ** can be used to restore the legacy behavior.
3823 **
3824 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
3825 ** API always returns a generic error code, [SQLITE_ERROR], following any
3826 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
3827 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
3828 ** specific [error codes] that better describes the error.
3829 ** We admit that this is a goofy design.  The problem has been fixed
3830 ** with the "v2" interface.  If you prepare all of your SQL statements
3831 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead
3832 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
3833 ** then the more specific [error codes] are returned directly
3834 ** by sqlite3_step().  The use of the "v2" interface is recommended.
3835 */
3836 SQLITE_API int SQLITE_STDCALL sqlite3_step(sqlite3_stmt*);
3837 
3838 /*
3839 ** CAPI3REF: Number of columns in a result set
3840 ** METHOD: sqlite3_stmt
3841 **
3842 ** ^The sqlite3_data_count(P) interface returns the number of columns in the
3843 ** current row of the result set of [prepared statement] P.
3844 ** ^If prepared statement P does not have results ready to return
3845 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
3846 ** interfaces) then sqlite3_data_count(P) returns 0.
3847 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
3848 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
3849 ** [sqlite3_step](P) returned [SQLITE_DONE].  ^The sqlite3_data_count(P)
3850 ** will return non-zero if previous call to [sqlite3_step](P) returned
3851 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
3852 ** where it always returns zero since each step of that multi-step
3853 ** pragma returns 0 columns of data.
3854 **
3855 ** See also: [sqlite3_column_count()]
3856 */
3857 SQLITE_API int SQLITE_STDCALL sqlite3_data_count(sqlite3_stmt *pStmt);
3858 
3859 /*
3860 ** CAPI3REF: Fundamental Datatypes
3861 ** KEYWORDS: SQLITE_TEXT
3862 **
3863 ** ^(Every value in SQLite has one of five fundamental datatypes:
3864 **
3865 ** <ul>
3866 ** <li> 64-bit signed integer
3867 ** <li> 64-bit IEEE floating point number
3868 ** <li> string
3869 ** <li> BLOB
3870 ** <li> NULL
3871 ** </ul>)^
3872 **
3873 ** These constants are codes for each of those types.
3874 **
3875 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
3876 ** for a completely different meaning.  Software that links against both
3877 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
3878 ** SQLITE_TEXT.
3879 */
3880 #define SQLITE_INTEGER  1
3881 #define SQLITE_FLOAT    2
3882 #define SQLITE_BLOB     4
3883 #define SQLITE_NULL     5
3884 #ifdef SQLITE_TEXT
3885 # undef SQLITE_TEXT
3886 #else
3887 # define SQLITE_TEXT     3
3888 #endif
3889 #define SQLITE3_TEXT     3
3890 
3891 /*
3892 ** CAPI3REF: Result Values From A Query
3893 ** KEYWORDS: {column access functions}
3894 ** METHOD: sqlite3_stmt
3895 **
3896 ** These routines form the "result set" interface.
3897 **
3898 ** ^These routines return information about a single column of the current
3899 ** result row of a query.  ^In every case the first argument is a pointer
3900 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
3901 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
3902 ** and the second argument is the index of the column for which information
3903 ** should be returned. ^The leftmost column of the result set has the index 0.
3904 ** ^The number of columns in the result can be determined using
3905 ** [sqlite3_column_count()].
3906 **
3907 ** If the SQL statement does not currently point to a valid row, or if the
3908 ** column index is out of range, the result is undefined.
3909 ** These routines may only be called when the most recent call to
3910 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
3911 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
3912 ** If any of these routines are called after [sqlite3_reset()] or
3913 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
3914 ** something other than [SQLITE_ROW], the results are undefined.
3915 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
3916 ** are called from a different thread while any of these routines
3917 ** are pending, then the results are undefined.
3918 **
3919 ** ^The sqlite3_column_type() routine returns the
3920 ** [SQLITE_INTEGER | datatype code] for the initial data type
3921 ** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
3922 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].  The value
3923 ** returned by sqlite3_column_type() is only meaningful if no type
3924 ** conversions have occurred as described below.  After a type conversion,
3925 ** the value returned by sqlite3_column_type() is undefined.  Future
3926 ** versions of SQLite may change the behavior of sqlite3_column_type()
3927 ** following a type conversion.
3928 **
3929 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
3930 ** routine returns the number of bytes in that BLOB or string.
3931 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
3932 ** the string to UTF-8 and then returns the number of bytes.
3933 ** ^If the result is a numeric value then sqlite3_column_bytes() uses
3934 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
3935 ** the number of bytes in that string.
3936 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
3937 **
3938 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
3939 ** routine returns the number of bytes in that BLOB or string.
3940 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
3941 ** the string to UTF-16 and then returns the number of bytes.
3942 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
3943 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
3944 ** the number of bytes in that string.
3945 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
3946 **
3947 ** ^The values returned by [sqlite3_column_bytes()] and
3948 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
3949 ** of the string.  ^For clarity: the values returned by
3950 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
3951 ** bytes in the string, not the number of characters.
3952 **
3953 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
3954 ** even empty strings, are always zero-terminated.  ^The return
3955 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
3956 **
3957 ** ^The object returned by [sqlite3_column_value()] is an
3958 ** [unprotected sqlite3_value] object.  An unprotected sqlite3_value object
3959 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()].
3960 ** If the [unprotected sqlite3_value] object returned by
3961 ** [sqlite3_column_value()] is used in any other way, including calls
3962 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
3963 ** or [sqlite3_value_bytes()], then the behavior is undefined.
3964 **
3965 ** These routines attempt to convert the value where appropriate.  ^For
3966 ** example, if the internal representation is FLOAT and a text result
3967 ** is requested, [sqlite3_snprintf()] is used internally to perform the
3968 ** conversion automatically.  ^(The following table details the conversions
3969 ** that are applied:
3970 **
3971 ** <blockquote>
3972 ** <table border="1">
3973 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
3974 **
3975 ** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
3976 ** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
3977 ** <tr><td>  NULL    <td>   TEXT    <td> Result is a NULL pointer
3978 ** <tr><td>  NULL    <td>   BLOB    <td> Result is a NULL pointer
3979 ** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
3980 ** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
3981 ** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
3982 ** <tr><td>  FLOAT   <td> INTEGER   <td> [CAST] to INTEGER
3983 ** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
3984 ** <tr><td>  FLOAT   <td>   BLOB    <td> [CAST] to BLOB
3985 ** <tr><td>  TEXT    <td> INTEGER   <td> [CAST] to INTEGER
3986 ** <tr><td>  TEXT    <td>  FLOAT    <td> [CAST] to REAL
3987 ** <tr><td>  TEXT    <td>   BLOB    <td> No change
3988 ** <tr><td>  BLOB    <td> INTEGER   <td> [CAST] to INTEGER
3989 ** <tr><td>  BLOB    <td>  FLOAT    <td> [CAST] to REAL
3990 ** <tr><td>  BLOB    <td>   TEXT    <td> Add a zero terminator if needed
3991 ** </table>
3992 ** </blockquote>)^
3993 **
3994 ** The table above makes reference to standard C library functions atoi()
3995 ** and atof().  SQLite does not really use these functions.  It has its
3996 ** own equivalent internal routines.  The atoi() and atof() names are
3997 ** used in the table for brevity and because they are familiar to most
3998 ** C programmers.
3999 **
4000 ** Note that when type conversions occur, pointers returned by prior
4001 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
4002 ** sqlite3_column_text16() may be invalidated.
4003 ** Type conversions and pointer invalidations might occur
4004 ** in the following cases:
4005 **
4006 ** <ul>
4007 ** <li> The initial content is a BLOB and sqlite3_column_text() or
4008 **      sqlite3_column_text16() is called.  A zero-terminator might
4009 **      need to be added to the string.</li>
4010 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
4011 **      sqlite3_column_text16() is called.  The content must be converted
4012 **      to UTF-16.</li>
4013 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
4014 **      sqlite3_column_text() is called.  The content must be converted
4015 **      to UTF-8.</li>
4016 ** </ul>
4017 **
4018 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
4019 ** not invalidate a prior pointer, though of course the content of the buffer
4020 ** that the prior pointer references will have been modified.  Other kinds
4021 ** of conversion are done in place when it is possible, but sometimes they
4022 ** are not possible and in those cases prior pointers are invalidated.
4023 **
4024 ** The safest and easiest to remember policy is to invoke these routines
4025 ** in one of the following ways:
4026 **
4027 ** <ul>
4028 **  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
4029 **  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
4030 **  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
4031 ** </ul>
4032 **
4033 ** In other words, you should call sqlite3_column_text(),
4034 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
4035 ** into the desired format, then invoke sqlite3_column_bytes() or
4036 ** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
4037 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
4038 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
4039 ** with calls to sqlite3_column_bytes().
4040 **
4041 ** ^The pointers returned are valid until a type conversion occurs as
4042 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
4043 ** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
4044 ** and BLOBs is freed automatically.  Do <b>not</b> pass the pointers returned
4045 ** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
4046 ** [sqlite3_free()].
4047 **
4048 ** ^(If a memory allocation error occurs during the evaluation of any
4049 ** of these routines, a default value is returned.  The default value
4050 ** is either the integer 0, the floating point number 0.0, or a NULL
4051 ** pointer.  Subsequent calls to [sqlite3_errcode()] will return
4052 ** [SQLITE_NOMEM].)^
4053 */
4054 SQLITE_API const void *SQLITE_STDCALL sqlite3_column_blob(sqlite3_stmt*, int iCol);
4055 SQLITE_API int SQLITE_STDCALL sqlite3_column_bytes(sqlite3_stmt*, int iCol);
4056 SQLITE_API int SQLITE_STDCALL sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
4057 SQLITE_API double SQLITE_STDCALL sqlite3_column_double(sqlite3_stmt*, int iCol);
4058 SQLITE_API int SQLITE_STDCALL sqlite3_column_int(sqlite3_stmt*, int iCol);
4059 SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_column_int64(sqlite3_stmt*, int iCol);
4060 SQLITE_API const unsigned char *SQLITE_STDCALL sqlite3_column_text(sqlite3_stmt*, int iCol);
4061 SQLITE_API const void *SQLITE_STDCALL sqlite3_column_text16(sqlite3_stmt*, int iCol);
4062 SQLITE_API int SQLITE_STDCALL sqlite3_column_type(sqlite3_stmt*, int iCol);
4063 SQLITE_API sqlite3_value *SQLITE_STDCALL sqlite3_column_value(sqlite3_stmt*, int iCol);
4064 
4065 /*
4066 ** CAPI3REF: Destroy A Prepared Statement Object
4067 ** DESTRUCTOR: sqlite3_stmt
4068 **
4069 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
4070 ** ^If the most recent evaluation of the statement encountered no errors
4071 ** or if the statement is never been evaluated, then sqlite3_finalize() returns
4072 ** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
4073 ** sqlite3_finalize(S) returns the appropriate [error code] or
4074 ** [extended error code].
4075 **
4076 ** ^The sqlite3_finalize(S) routine can be called at any point during
4077 ** the life cycle of [prepared statement] S:
4078 ** before statement S is ever evaluated, after
4079 ** one or more calls to [sqlite3_reset()], or after any call
4080 ** to [sqlite3_step()] regardless of whether or not the statement has
4081 ** completed execution.
4082 **
4083 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
4084 **
4085 ** The application must finalize every [prepared statement] in order to avoid
4086 ** resource leaks.  It is a grievous error for the application to try to use
4087 ** a prepared statement after it has been finalized.  Any use of a prepared
4088 ** statement after it has been finalized can result in undefined and
4089 ** undesirable behavior such as segfaults and heap corruption.
4090 */
4091 SQLITE_API int SQLITE_STDCALL sqlite3_finalize(sqlite3_stmt *pStmt);
4092 
4093 /*
4094 ** CAPI3REF: Reset A Prepared Statement Object
4095 ** METHOD: sqlite3_stmt
4096 **
4097 ** The sqlite3_reset() function is called to reset a [prepared statement]
4098 ** object back to its initial state, ready to be re-executed.
4099 ** ^Any SQL statement variables that had values bound to them using
4100 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
4101 ** Use [sqlite3_clear_bindings()] to reset the bindings.
4102 **
4103 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
4104 ** back to the beginning of its program.
4105 **
4106 ** ^If the most recent call to [sqlite3_step(S)] for the
4107 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
4108 ** or if [sqlite3_step(S)] has never before been called on S,
4109 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
4110 **
4111 ** ^If the most recent call to [sqlite3_step(S)] for the
4112 ** [prepared statement] S indicated an error, then
4113 ** [sqlite3_reset(S)] returns an appropriate [error code].
4114 **
4115 ** ^The [sqlite3_reset(S)] interface does not change the values
4116 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
4117 */
4118 SQLITE_API int SQLITE_STDCALL sqlite3_reset(sqlite3_stmt *pStmt);
4119 
4120 /*
4121 ** CAPI3REF: Create Or Redefine SQL Functions
4122 ** KEYWORDS: {function creation routines}
4123 ** KEYWORDS: {application-defined SQL function}
4124 ** KEYWORDS: {application-defined SQL functions}
4125 ** METHOD: sqlite3
4126 **
4127 ** ^These functions (collectively known as "function creation routines")
4128 ** are used to add SQL functions or aggregates or to redefine the behavior
4129 ** of existing SQL functions or aggregates.  The only differences between
4130 ** these routines are the text encoding expected for
4131 ** the second parameter (the name of the function being created)
4132 ** and the presence or absence of a destructor callback for
4133 ** the application data pointer.
4134 **
4135 ** ^The first parameter is the [database connection] to which the SQL
4136 ** function is to be added.  ^If an application uses more than one database
4137 ** connection then application-defined SQL functions must be added
4138 ** to each database connection separately.
4139 **
4140 ** ^The second parameter is the name of the SQL function to be created or
4141 ** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
4142 ** representation, exclusive of the zero-terminator.  ^Note that the name
4143 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
4144 ** ^Any attempt to create a function with a longer name
4145 ** will result in [SQLITE_MISUSE] being returned.
4146 **
4147 ** ^The third parameter (nArg)
4148 ** is the number of arguments that the SQL function or
4149 ** aggregate takes. ^If this parameter is -1, then the SQL function or
4150 ** aggregate may take any number of arguments between 0 and the limit
4151 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
4152 ** parameter is less than -1 or greater than 127 then the behavior is
4153 ** undefined.
4154 **
4155 ** ^The fourth parameter, eTextRep, specifies what
4156 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
4157 ** its parameters.  The application should set this parameter to
4158 ** [SQLITE_UTF16LE] if the function implementation invokes
4159 ** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
4160 ** implementation invokes [sqlite3_value_text16be()] on an input, or
4161 ** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
4162 ** otherwise.  ^The same SQL function may be registered multiple times using
4163 ** different preferred text encodings, with different implementations for
4164 ** each encoding.
4165 ** ^When multiple implementations of the same function are available, SQLite
4166 ** will pick the one that involves the least amount of data conversion.
4167 **
4168 ** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
4169 ** to signal that the function will always return the same result given
4170 ** the same inputs within a single SQL statement.  Most SQL functions are
4171 ** deterministic.  The built-in [random()] SQL function is an example of a
4172 ** function that is not deterministic.  The SQLite query planner is able to
4173 ** perform additional optimizations on deterministic functions, so use
4174 ** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
4175 **
4176 ** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
4177 ** function can gain access to this pointer using [sqlite3_user_data()].)^
4178 **
4179 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
4180 ** pointers to C-language functions that implement the SQL function or
4181 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
4182 ** callback only; NULL pointers must be passed as the xStep and xFinal
4183 ** parameters. ^An aggregate SQL function requires an implementation of xStep
4184 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
4185 ** SQL function or aggregate, pass NULL pointers for all three function
4186 ** callbacks.
4187 **
4188 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
4189 ** then it is destructor for the application data pointer.
4190 ** The destructor is invoked when the function is deleted, either by being
4191 ** overloaded or when the database connection closes.)^
4192 ** ^The destructor is also invoked if the call to
4193 ** sqlite3_create_function_v2() fails.
4194 ** ^When the destructor callback of the tenth parameter is invoked, it
4195 ** is passed a single argument which is a copy of the application data
4196 ** pointer which was the fifth parameter to sqlite3_create_function_v2().
4197 **
4198 ** ^It is permitted to register multiple implementations of the same
4199 ** functions with the same name but with either differing numbers of
4200 ** arguments or differing preferred text encodings.  ^SQLite will use
4201 ** the implementation that most closely matches the way in which the
4202 ** SQL function is used.  ^A function implementation with a non-negative
4203 ** nArg parameter is a better match than a function implementation with
4204 ** a negative nArg.  ^A function where the preferred text encoding
4205 ** matches the database encoding is a better
4206 ** match than a function where the encoding is different.
4207 ** ^A function where the encoding difference is between UTF16le and UTF16be
4208 ** is a closer match than a function where the encoding difference is
4209 ** between UTF8 and UTF16.
4210 **
4211 ** ^Built-in functions may be overloaded by new application-defined functions.
4212 **
4213 ** ^An application-defined function is permitted to call other
4214 ** SQLite interfaces.  However, such calls must not
4215 ** close the database connection nor finalize or reset the prepared
4216 ** statement in which the function is running.
4217 */
4218 SQLITE_API int SQLITE_STDCALL sqlite3_create_function(
4219   sqlite3 *db,
4220   const char *zFunctionName,
4221   int nArg,
4222   int eTextRep,
4223   void *pApp,
4224   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4225   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4226   void (*xFinal)(sqlite3_context*)
4227 );
4228 SQLITE_API int SQLITE_STDCALL sqlite3_create_function16(
4229   sqlite3 *db,
4230   const void *zFunctionName,
4231   int nArg,
4232   int eTextRep,
4233   void *pApp,
4234   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4235   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4236   void (*xFinal)(sqlite3_context*)
4237 );
4238 SQLITE_API int SQLITE_STDCALL sqlite3_create_function_v2(
4239   sqlite3 *db,
4240   const char *zFunctionName,
4241   int nArg,
4242   int eTextRep,
4243   void *pApp,
4244   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
4245   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
4246   void (*xFinal)(sqlite3_context*),
4247   void(*xDestroy)(void*)
4248 );
4249 
4250 /*
4251 ** CAPI3REF: Text Encodings
4252 **
4253 ** These constant define integer codes that represent the various
4254 ** text encodings supported by SQLite.
4255 */
4256 #define SQLITE_UTF8           1    /* IMP: R-37514-35566 */
4257 #define SQLITE_UTF16LE        2    /* IMP: R-03371-37637 */
4258 #define SQLITE_UTF16BE        3    /* IMP: R-51971-34154 */
4259 #define SQLITE_UTF16          4    /* Use native byte order */
4260 #define SQLITE_ANY            5    /* Deprecated */
4261 #define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
4262 
4263 /*
4264 ** CAPI3REF: Function Flags
4265 **
4266 ** These constants may be ORed together with the
4267 ** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
4268 ** to [sqlite3_create_function()], [sqlite3_create_function16()], or
4269 ** [sqlite3_create_function_v2()].
4270 */
4271 #define SQLITE_DETERMINISTIC    0x800
4272 
4273 /*
4274 ** CAPI3REF: Deprecated Functions
4275 ** DEPRECATED
4276 **
4277 ** These functions are [deprecated].  In order to maintain
4278 ** backwards compatibility with older code, these functions continue
4279 ** to be supported.  However, new applications should avoid
4280 ** the use of these functions.  To encourage programmers to avoid
4281 ** these functions, we will not explain what they do.
4282 */
4283 #ifndef SQLITE_OMIT_DEPRECATED
4284 SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_aggregate_count(sqlite3_context*);
4285 SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_expired(sqlite3_stmt*);
4286 SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
4287 SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_global_recover(void);
4288 SQLITE_API SQLITE_DEPRECATED void SQLITE_STDCALL sqlite3_thread_cleanup(void);
4289 SQLITE_API SQLITE_DEPRECATED int SQLITE_STDCALL sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
4290                       void*,sqlite3_int64);
4291 #endif
4292 
4293 /*
4294 ** CAPI3REF: Obtaining SQL Function Parameter Values
4295 ** METHOD: sqlite3_value
4296 **
4297 ** The C-language implementation of SQL functions and aggregates uses
4298 ** this set of interface routines to access the parameter values on
4299 ** the function or aggregate.
4300 **
4301 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters
4302 ** to [sqlite3_create_function()] and [sqlite3_create_function16()]
4303 ** define callbacks that implement the SQL functions and aggregates.
4304 ** The 3rd parameter to these callbacks is an array of pointers to
4305 ** [protected sqlite3_value] objects.  There is one [sqlite3_value] object for
4306 ** each parameter to the SQL function.  These routines are used to
4307 ** extract values from the [sqlite3_value] objects.
4308 **
4309 ** These routines work only with [protected sqlite3_value] objects.
4310 ** Any attempt to use these routines on an [unprotected sqlite3_value]
4311 ** object results in undefined behavior.
4312 **
4313 ** ^These routines work just like the corresponding [column access functions]
4314 ** except that these routines take a single [protected sqlite3_value] object
4315 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
4316 **
4317 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
4318 ** in the native byte-order of the host machine.  ^The
4319 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
4320 ** extract UTF-16 strings as big-endian and little-endian respectively.
4321 **
4322 ** ^(The sqlite3_value_numeric_type() interface attempts to apply
4323 ** numeric affinity to the value.  This means that an attempt is
4324 ** made to convert the value to an integer or floating point.  If
4325 ** such a conversion is possible without loss of information (in other
4326 ** words, if the value is a string that looks like a number)
4327 ** then the conversion is performed.  Otherwise no conversion occurs.
4328 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
4329 **
4330 ** Please pay particular attention to the fact that the pointer returned
4331 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
4332 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
4333 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
4334 ** or [sqlite3_value_text16()].
4335 **
4336 ** These routines must be called from the same thread as
4337 ** the SQL function that supplied the [sqlite3_value*] parameters.
4338 */
4339 SQLITE_API const void *SQLITE_STDCALL sqlite3_value_blob(sqlite3_value*);
4340 SQLITE_API int SQLITE_STDCALL sqlite3_value_bytes(sqlite3_value*);
4341 SQLITE_API int SQLITE_STDCALL sqlite3_value_bytes16(sqlite3_value*);
4342 SQLITE_API double SQLITE_STDCALL sqlite3_value_double(sqlite3_value*);
4343 SQLITE_API int SQLITE_STDCALL sqlite3_value_int(sqlite3_value*);
4344 SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_value_int64(sqlite3_value*);
4345 SQLITE_API const unsigned char *SQLITE_STDCALL sqlite3_value_text(sqlite3_value*);
4346 SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16(sqlite3_value*);
4347 SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16le(sqlite3_value*);
4348 SQLITE_API const void *SQLITE_STDCALL sqlite3_value_text16be(sqlite3_value*);
4349 SQLITE_API int SQLITE_STDCALL sqlite3_value_type(sqlite3_value*);
4350 SQLITE_API int SQLITE_STDCALL sqlite3_value_numeric_type(sqlite3_value*);
4351 
4352 /*
4353 ** CAPI3REF: Obtain Aggregate Function Context
4354 ** METHOD: sqlite3_context
4355 **
4356 ** Implementations of aggregate SQL functions use this
4357 ** routine to allocate memory for storing their state.
4358 **
4359 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called
4360 ** for a particular aggregate function, SQLite
4361 ** allocates N of memory, zeroes out that memory, and returns a pointer
4362 ** to the new memory. ^On second and subsequent calls to
4363 ** sqlite3_aggregate_context() for the same aggregate function instance,
4364 ** the same buffer is returned.  Sqlite3_aggregate_context() is normally
4365 ** called once for each invocation of the xStep callback and then one
4366 ** last time when the xFinal callback is invoked.  ^(When no rows match
4367 ** an aggregate query, the xStep() callback of the aggregate function
4368 ** implementation is never called and xFinal() is called exactly once.
4369 ** In those cases, sqlite3_aggregate_context() might be called for the
4370 ** first time from within xFinal().)^
4371 **
4372 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
4373 ** when first called if N is less than or equal to zero or if a memory
4374 ** allocate error occurs.
4375 **
4376 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
4377 ** determined by the N parameter on first successful call.  Changing the
4378 ** value of N in subsequent call to sqlite3_aggregate_context() within
4379 ** the same aggregate function instance will not resize the memory
4380 ** allocation.)^  Within the xFinal callback, it is customary to set
4381 ** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
4382 ** pointless memory allocations occur.
4383 **
4384 ** ^SQLite automatically frees the memory allocated by
4385 ** sqlite3_aggregate_context() when the aggregate query concludes.
4386 **
4387 ** The first parameter must be a copy of the
4388 ** [sqlite3_context | SQL function context] that is the first parameter
4389 ** to the xStep or xFinal callback routine that implements the aggregate
4390 ** function.
4391 **
4392 ** This routine must be called from the same thread in which
4393 ** the aggregate SQL function is running.
4394 */
4395 SQLITE_API void *SQLITE_STDCALL sqlite3_aggregate_context(sqlite3_context*, int nBytes);
4396 
4397 /*
4398 ** CAPI3REF: User Data For Functions
4399 ** METHOD: sqlite3_context
4400 **
4401 ** ^The sqlite3_user_data() interface returns a copy of
4402 ** the pointer that was the pUserData parameter (the 5th parameter)
4403 ** of the [sqlite3_create_function()]
4404 ** and [sqlite3_create_function16()] routines that originally
4405 ** registered the application defined function.
4406 **
4407 ** This routine must be called from the same thread in which
4408 ** the application-defined function is running.
4409 */
4410 SQLITE_API void *SQLITE_STDCALL sqlite3_user_data(sqlite3_context*);
4411 
4412 /*
4413 ** CAPI3REF: Database Connection For Functions
4414 ** METHOD: sqlite3_context
4415 **
4416 ** ^The sqlite3_context_db_handle() interface returns a copy of
4417 ** the pointer to the [database connection] (the 1st parameter)
4418 ** of the [sqlite3_create_function()]
4419 ** and [sqlite3_create_function16()] routines that originally
4420 ** registered the application defined function.
4421 */
4422 SQLITE_API sqlite3 *SQLITE_STDCALL sqlite3_context_db_handle(sqlite3_context*);
4423 
4424 /*
4425 ** CAPI3REF: Function Auxiliary Data
4426 ** METHOD: sqlite3_context
4427 **
4428 ** These functions may be used by (non-aggregate) SQL functions to
4429 ** associate metadata with argument values. If the same value is passed to
4430 ** multiple invocations of the same SQL function during query execution, under
4431 ** some circumstances the associated metadata may be preserved.  An example
4432 ** of where this might be useful is in a regular-expression matching
4433 ** function. The compiled version of the regular expression can be stored as
4434 ** metadata associated with the pattern string.
4435 ** Then as long as the pattern string remains the same,
4436 ** the compiled regular expression can be reused on multiple
4437 ** invocations of the same function.
4438 **
4439 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata
4440 ** associated by the sqlite3_set_auxdata() function with the Nth argument
4441 ** value to the application-defined function. ^If there is no metadata
4442 ** associated with the function argument, this sqlite3_get_auxdata() interface
4443 ** returns a NULL pointer.
4444 **
4445 ** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
4446 ** argument of the application-defined function.  ^Subsequent
4447 ** calls to sqlite3_get_auxdata(C,N) return P from the most recent
4448 ** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
4449 ** NULL if the metadata has been discarded.
4450 ** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
4451 ** SQLite will invoke the destructor function X with parameter P exactly
4452 ** once, when the metadata is discarded.
4453 ** SQLite is free to discard the metadata at any time, including: <ul>
4454 ** <li> when the corresponding function parameter changes, or
4455 ** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
4456 **      SQL statement, or
4457 ** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or
4458 ** <li> during the original sqlite3_set_auxdata() call when a memory
4459 **      allocation error occurs. </ul>)^
4460 **
4461 ** Note the last bullet in particular.  The destructor X in
4462 ** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
4463 ** sqlite3_set_auxdata() interface even returns.  Hence sqlite3_set_auxdata()
4464 ** should be called near the end of the function implementation and the
4465 ** function implementation should not make any use of P after
4466 ** sqlite3_set_auxdata() has been called.
4467 **
4468 ** ^(In practice, metadata is preserved between function calls for
4469 ** function parameters that are compile-time constants, including literal
4470 ** values and [parameters] and expressions composed from the same.)^
4471 **
4472 ** These routines must be called from the same thread in which
4473 ** the SQL function is running.
4474 */
4475 SQLITE_API void *SQLITE_STDCALL sqlite3_get_auxdata(sqlite3_context*, int N);
4476 SQLITE_API void SQLITE_STDCALL sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
4477 
4478 
4479 /*
4480 ** CAPI3REF: Constants Defining Special Destructor Behavior
4481 **
4482 ** These are special values for the destructor that is passed in as the
4483 ** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
4484 ** argument is SQLITE_STATIC, it means that the content pointer is constant
4485 ** and will never change.  It does not need to be destroyed.  ^The
4486 ** SQLITE_TRANSIENT value means that the content will likely change in
4487 ** the near future and that SQLite should make its own private copy of
4488 ** the content before returning.
4489 **
4490 ** The typedef is necessary to work around problems in certain
4491 ** C++ compilers.
4492 */
4493 typedef void (*sqlite3_destructor_type)(void*);
4494 #define SQLITE_STATIC      ((sqlite3_destructor_type)0)
4495 #define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
4496 
4497 /*
4498 ** CAPI3REF: Setting The Result Of An SQL Function
4499 ** METHOD: sqlite3_context
4500 **
4501 ** These routines are used by the xFunc or xFinal callbacks that
4502 ** implement SQL functions and aggregates.  See
4503 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
4504 ** for additional information.
4505 **
4506 ** These functions work very much like the [parameter binding] family of
4507 ** functions used to bind values to host parameters in prepared statements.
4508 ** Refer to the [SQL parameter] documentation for additional information.
4509 **
4510 ** ^The sqlite3_result_blob() interface sets the result from
4511 ** an application-defined function to be the BLOB whose content is pointed
4512 ** to by the second parameter and which is N bytes long where N is the
4513 ** third parameter.
4514 **
4515 ** ^The sqlite3_result_zeroblob() interfaces set the result of
4516 ** the application-defined function to be a BLOB containing all zero
4517 ** bytes and N bytes in size, where N is the value of the 2nd parameter.
4518 **
4519 ** ^The sqlite3_result_double() interface sets the result from
4520 ** an application-defined function to be a floating point value specified
4521 ** by its 2nd argument.
4522 **
4523 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
4524 ** cause the implemented SQL function to throw an exception.
4525 ** ^SQLite uses the string pointed to by the
4526 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
4527 ** as the text of an error message.  ^SQLite interprets the error
4528 ** message string from sqlite3_result_error() as UTF-8. ^SQLite
4529 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
4530 ** byte order.  ^If the third parameter to sqlite3_result_error()
4531 ** or sqlite3_result_error16() is negative then SQLite takes as the error
4532 ** message all text up through the first zero character.
4533 ** ^If the third parameter to sqlite3_result_error() or
4534 ** sqlite3_result_error16() is non-negative then SQLite takes that many
4535 ** bytes (not characters) from the 2nd parameter as the error message.
4536 ** ^The sqlite3_result_error() and sqlite3_result_error16()
4537 ** routines make a private copy of the error message text before
4538 ** they return.  Hence, the calling function can deallocate or
4539 ** modify the text after they return without harm.
4540 ** ^The sqlite3_result_error_code() function changes the error code
4541 ** returned by SQLite as a result of an error in a function.  ^By default,
4542 ** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
4543 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
4544 **
4545 ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
4546 ** error indicating that a string or BLOB is too long to represent.
4547 **
4548 ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
4549 ** error indicating that a memory allocation failed.
4550 **
4551 ** ^The sqlite3_result_int() interface sets the return value
4552 ** of the application-defined function to be the 32-bit signed integer
4553 ** value given in the 2nd argument.
4554 ** ^The sqlite3_result_int64() interface sets the return value
4555 ** of the application-defined function to be the 64-bit signed integer
4556 ** value given in the 2nd argument.
4557 **
4558 ** ^The sqlite3_result_null() interface sets the return value
4559 ** of the application-defined function to be NULL.
4560 **
4561 ** ^The sqlite3_result_text(), sqlite3_result_text16(),
4562 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
4563 ** set the return value of the application-defined function to be
4564 ** a text string which is represented as UTF-8, UTF-16 native byte order,
4565 ** UTF-16 little endian, or UTF-16 big endian, respectively.
4566 ** ^The sqlite3_result_text64() interface sets the return value of an
4567 ** application-defined function to be a text string in an encoding
4568 ** specified by the fifth (and last) parameter, which must be one
4569 ** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
4570 ** ^SQLite takes the text result from the application from
4571 ** the 2nd parameter of the sqlite3_result_text* interfaces.
4572 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4573 ** is negative, then SQLite takes result text from the 2nd parameter
4574 ** through the first zero character.
4575 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
4576 ** is non-negative, then as many bytes (not characters) of the text
4577 ** pointed to by the 2nd parameter are taken as the application-defined
4578 ** function result.  If the 3rd parameter is non-negative, then it
4579 ** must be the byte offset into the string where the NUL terminator would
4580 ** appear if the string where NUL terminated.  If any NUL characters occur
4581 ** in the string at a byte offset that is less than the value of the 3rd
4582 ** parameter, then the resulting string will contain embedded NULs and the
4583 ** result of expressions operating on strings with embedded NULs is undefined.
4584 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4585 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
4586 ** function as the destructor on the text or BLOB result when it has
4587 ** finished using that result.
4588 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
4589 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
4590 ** assumes that the text or BLOB result is in constant space and does not
4591 ** copy the content of the parameter nor call a destructor on the content
4592 ** when it has finished using that result.
4593 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
4594 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
4595 ** then SQLite makes a copy of the result into space obtained from
4596 ** from [sqlite3_malloc()] before it returns.
4597 **
4598 ** ^The sqlite3_result_value() interface sets the result of
4599 ** the application-defined function to be a copy the
4600 ** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
4601 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
4602 ** so that the [sqlite3_value] specified in the parameter may change or
4603 ** be deallocated after sqlite3_result_value() returns without harm.
4604 ** ^A [protected sqlite3_value] object may always be used where an
4605 ** [unprotected sqlite3_value] object is required, so either
4606 ** kind of [sqlite3_value] object can be used with this interface.
4607 **
4608 ** If these routines are called from within the different thread
4609 ** than the one containing the application-defined function that received
4610 ** the [sqlite3_context] pointer, the results are undefined.
4611 */
4612 SQLITE_API void SQLITE_STDCALL sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
4613 SQLITE_API void SQLITE_STDCALL sqlite3_result_blob64(sqlite3_context*,const void*,
4614                            sqlite3_uint64,void(*)(void*));
4615 SQLITE_API void SQLITE_STDCALL sqlite3_result_double(sqlite3_context*, double);
4616 SQLITE_API void SQLITE_STDCALL sqlite3_result_error(sqlite3_context*, const char*, int);
4617 SQLITE_API void SQLITE_STDCALL sqlite3_result_error16(sqlite3_context*, const void*, int);
4618 SQLITE_API void SQLITE_STDCALL sqlite3_result_error_toobig(sqlite3_context*);
4619 SQLITE_API void SQLITE_STDCALL sqlite3_result_error_nomem(sqlite3_context*);
4620 SQLITE_API void SQLITE_STDCALL sqlite3_result_error_code(sqlite3_context*, int);
4621 SQLITE_API void SQLITE_STDCALL sqlite3_result_int(sqlite3_context*, int);
4622 SQLITE_API void SQLITE_STDCALL sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
4623 SQLITE_API void SQLITE_STDCALL sqlite3_result_null(sqlite3_context*);
4624 SQLITE_API void SQLITE_STDCALL sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
4625 SQLITE_API void SQLITE_STDCALL sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
4626                            void(*)(void*), unsigned char encoding);
4627 SQLITE_API void SQLITE_STDCALL sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
4628 SQLITE_API void SQLITE_STDCALL sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
4629 SQLITE_API void SQLITE_STDCALL sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
4630 SQLITE_API void SQLITE_STDCALL sqlite3_result_value(sqlite3_context*, sqlite3_value*);
4631 SQLITE_API void SQLITE_STDCALL sqlite3_result_zeroblob(sqlite3_context*, int n);
4632 
4633 /*
4634 ** CAPI3REF: Define New Collating Sequences
4635 ** METHOD: sqlite3
4636 **
4637 ** ^These functions add, remove, or modify a [collation] associated
4638 ** with the [database connection] specified as the first argument.
4639 **
4640 ** ^The name of the collation is a UTF-8 string
4641 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
4642 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
4643 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
4644 ** considered to be the same name.
4645 **
4646 ** ^(The third argument (eTextRep) must be one of the constants:
4647 ** <ul>
4648 ** <li> [SQLITE_UTF8],
4649 ** <li> [SQLITE_UTF16LE],
4650 ** <li> [SQLITE_UTF16BE],
4651 ** <li> [SQLITE_UTF16], or
4652 ** <li> [SQLITE_UTF16_ALIGNED].
4653 ** </ul>)^
4654 ** ^The eTextRep argument determines the encoding of strings passed
4655 ** to the collating function callback, xCallback.
4656 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
4657 ** force strings to be UTF16 with native byte order.
4658 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
4659 ** on an even byte address.
4660 **
4661 ** ^The fourth argument, pArg, is an application data pointer that is passed
4662 ** through as the first argument to the collating function callback.
4663 **
4664 ** ^The fifth argument, xCallback, is a pointer to the collating function.
4665 ** ^Multiple collating functions can be registered using the same name but
4666 ** with different eTextRep parameters and SQLite will use whichever
4667 ** function requires the least amount of data transformation.
4668 ** ^If the xCallback argument is NULL then the collating function is
4669 ** deleted.  ^When all collating functions having the same name are deleted,
4670 ** that collation is no longer usable.
4671 **
4672 ** ^The collating function callback is invoked with a copy of the pArg
4673 ** application data pointer and with two strings in the encoding specified
4674 ** by the eTextRep argument.  The collating function must return an
4675 ** integer that is negative, zero, or positive
4676 ** if the first string is less than, equal to, or greater than the second,
4677 ** respectively.  A collating function must always return the same answer
4678 ** given the same inputs.  If two or more collating functions are registered
4679 ** to the same collation name (using different eTextRep values) then all
4680 ** must give an equivalent answer when invoked with equivalent strings.
4681 ** The collating function must obey the following properties for all
4682 ** strings A, B, and C:
4683 **
4684 ** <ol>
4685 ** <li> If A==B then B==A.
4686 ** <li> If A==B and B==C then A==C.
4687 ** <li> If A&lt;B THEN B&gt;A.
4688 ** <li> If A&lt;B and B&lt;C then A&lt;C.
4689 ** </ol>
4690 **
4691 ** If a collating function fails any of the above constraints and that
4692 ** collating function is  registered and used, then the behavior of SQLite
4693 ** is undefined.
4694 **
4695 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
4696 ** with the addition that the xDestroy callback is invoked on pArg when
4697 ** the collating function is deleted.
4698 ** ^Collating functions are deleted when they are overridden by later
4699 ** calls to the collation creation functions or when the
4700 ** [database connection] is closed using [sqlite3_close()].
4701 **
4702 ** ^The xDestroy callback is <u>not</u> called if the
4703 ** sqlite3_create_collation_v2() function fails.  Applications that invoke
4704 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
4705 ** check the return code and dispose of the application data pointer
4706 ** themselves rather than expecting SQLite to deal with it for them.
4707 ** This is different from every other SQLite interface.  The inconsistency
4708 ** is unfortunate but cannot be changed without breaking backwards
4709 ** compatibility.
4710 **
4711 ** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
4712 */
4713 SQLITE_API int SQLITE_STDCALL sqlite3_create_collation(
4714   sqlite3*,
4715   const char *zName,
4716   int eTextRep,
4717   void *pArg,
4718   int(*xCompare)(void*,int,const void*,int,const void*)
4719 );
4720 SQLITE_API int SQLITE_STDCALL sqlite3_create_collation_v2(
4721   sqlite3*,
4722   const char *zName,
4723   int eTextRep,
4724   void *pArg,
4725   int(*xCompare)(void*,int,const void*,int,const void*),
4726   void(*xDestroy)(void*)
4727 );
4728 SQLITE_API int SQLITE_STDCALL sqlite3_create_collation16(
4729   sqlite3*,
4730   const void *zName,
4731   int eTextRep,
4732   void *pArg,
4733   int(*xCompare)(void*,int,const void*,int,const void*)
4734 );
4735 
4736 /*
4737 ** CAPI3REF: Collation Needed Callbacks
4738 ** METHOD: sqlite3
4739 **
4740 ** ^To avoid having to register all collation sequences before a database
4741 ** can be used, a single callback function may be registered with the
4742 ** [database connection] to be invoked whenever an undefined collation
4743 ** sequence is required.
4744 **
4745 ** ^If the function is registered using the sqlite3_collation_needed() API,
4746 ** then it is passed the names of undefined collation sequences as strings
4747 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
4748 ** the names are passed as UTF-16 in machine native byte order.
4749 ** ^A call to either function replaces the existing collation-needed callback.
4750 **
4751 ** ^(When the callback is invoked, the first argument passed is a copy
4752 ** of the second argument to sqlite3_collation_needed() or
4753 ** sqlite3_collation_needed16().  The second argument is the database
4754 ** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
4755 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
4756 ** sequence function required.  The fourth parameter is the name of the
4757 ** required collation sequence.)^
4758 **
4759 ** The callback function should register the desired collation using
4760 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
4761 ** [sqlite3_create_collation_v2()].
4762 */
4763 SQLITE_API int SQLITE_STDCALL sqlite3_collation_needed(
4764   sqlite3*,
4765   void*,
4766   void(*)(void*,sqlite3*,int eTextRep,const char*)
4767 );
4768 SQLITE_API int SQLITE_STDCALL sqlite3_collation_needed16(
4769   sqlite3*,
4770   void*,
4771   void(*)(void*,sqlite3*,int eTextRep,const void*)
4772 );
4773 
4774 #ifdef SQLITE_HAS_CODEC
4775 /*
4776 ** Specify the key for an encrypted database.  This routine should be
4777 ** called right after sqlite3_open().
4778 **
4779 ** The code to implement this API is not available in the public release
4780 ** of SQLite.
4781 */
4782 SQLITE_API int SQLITE_STDCALL sqlite3_key(
4783   sqlite3 *db,                   /* Database to be rekeyed */
4784   const void *pKey, int nKey     /* The key */
4785 );
4786 SQLITE_API int SQLITE_STDCALL sqlite3_key_v2(
4787   sqlite3 *db,                   /* Database to be rekeyed */
4788   const char *zDbName,           /* Name of the database */
4789   const void *pKey, int nKey     /* The key */
4790 );
4791 
4792 /*
4793 ** Change the key on an open database.  If the current database is not
4794 ** encrypted, this routine will encrypt it.  If pNew==0 or nNew==0, the
4795 ** database is decrypted.
4796 **
4797 ** The code to implement this API is not available in the public release
4798 ** of SQLite.
4799 */
4800 SQLITE_API int SQLITE_STDCALL sqlite3_rekey(
4801   sqlite3 *db,                   /* Database to be rekeyed */
4802   const void *pKey, int nKey     /* The new key */
4803 );
4804 SQLITE_API int SQLITE_STDCALL sqlite3_rekey_v2(
4805   sqlite3 *db,                   /* Database to be rekeyed */
4806   const char *zDbName,           /* Name of the database */
4807   const void *pKey, int nKey     /* The new key */
4808 );
4809 
4810 /*
4811 ** Specify the activation key for a SEE database.  Unless
4812 ** activated, none of the SEE routines will work.
4813 */
4814 SQLITE_API void SQLITE_STDCALL sqlite3_activate_see(
4815   const char *zPassPhrase        /* Activation phrase */
4816 );
4817 #endif
4818 
4819 #ifdef SQLITE_ENABLE_CEROD
4820 /*
4821 ** Specify the activation key for a CEROD database.  Unless
4822 ** activated, none of the CEROD routines will work.
4823 */
4824 SQLITE_API void SQLITE_STDCALL sqlite3_activate_cerod(
4825   const char *zPassPhrase        /* Activation phrase */
4826 );
4827 #endif
4828 
4829 /*
4830 ** CAPI3REF: Suspend Execution For A Short Time
4831 **
4832 ** The sqlite3_sleep() function causes the current thread to suspend execution
4833 ** for at least a number of milliseconds specified in its parameter.
4834 **
4835 ** If the operating system does not support sleep requests with
4836 ** millisecond time resolution, then the time will be rounded up to
4837 ** the nearest second. The number of milliseconds of sleep actually
4838 ** requested from the operating system is returned.
4839 **
4840 ** ^SQLite implements this interface by calling the xSleep()
4841 ** method of the default [sqlite3_vfs] object.  If the xSleep() method
4842 ** of the default VFS is not implemented correctly, or not implemented at
4843 ** all, then the behavior of sqlite3_sleep() may deviate from the description
4844 ** in the previous paragraphs.
4845 */
4846 SQLITE_API int SQLITE_STDCALL sqlite3_sleep(int);
4847 
4848 /*
4849 ** CAPI3REF: Name Of The Folder Holding Temporary Files
4850 **
4851 ** ^(If this global variable is made to point to a string which is
4852 ** the name of a folder (a.k.a. directory), then all temporary files
4853 ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
4854 ** will be placed in that directory.)^  ^If this variable
4855 ** is a NULL pointer, then SQLite performs a search for an appropriate
4856 ** temporary file directory.
4857 **
4858 ** Applications are strongly discouraged from using this global variable.
4859 ** It is required to set a temporary folder on Windows Runtime (WinRT).
4860 ** But for all other platforms, it is highly recommended that applications
4861 ** neither read nor write this variable.  This global variable is a relic
4862 ** that exists for backwards compatibility of legacy applications and should
4863 ** be avoided in new projects.
4864 **
4865 ** It is not safe to read or modify this variable in more than one
4866 ** thread at a time.  It is not safe to read or modify this variable
4867 ** if a [database connection] is being used at the same time in a separate
4868 ** thread.
4869 ** It is intended that this variable be set once
4870 ** as part of process initialization and before any SQLite interface
4871 ** routines have been called and that this variable remain unchanged
4872 ** thereafter.
4873 **
4874 ** ^The [temp_store_directory pragma] may modify this variable and cause
4875 ** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
4876 ** the [temp_store_directory pragma] always assumes that any string
4877 ** that this variable points to is held in memory obtained from
4878 ** [sqlite3_malloc] and the pragma may attempt to free that memory
4879 ** using [sqlite3_free].
4880 ** Hence, if this variable is modified directly, either it should be
4881 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4882 ** or else the use of the [temp_store_directory pragma] should be avoided.
4883 ** Except when requested by the [temp_store_directory pragma], SQLite
4884 ** does not free the memory that sqlite3_temp_directory points to.  If
4885 ** the application wants that memory to be freed, it must do
4886 ** so itself, taking care to only do so after all [database connection]
4887 ** objects have been destroyed.
4888 **
4889 ** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
4890 ** prior to calling [sqlite3_open] or [sqlite3_open_v2].  Otherwise, various
4891 ** features that require the use of temporary files may fail.  Here is an
4892 ** example of how to do this using C++ with the Windows Runtime:
4893 **
4894 ** <blockquote><pre>
4895 ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
4896 ** &nbsp;     TemporaryFolder->Path->Data();
4897 ** char zPathBuf&#91;MAX_PATH + 1&#93;;
4898 ** memset(zPathBuf, 0, sizeof(zPathBuf));
4899 ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
4900 ** &nbsp;     NULL, NULL);
4901 ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
4902 ** </pre></blockquote>
4903 */
4904 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
4905 
4906 /*
4907 ** CAPI3REF: Name Of The Folder Holding Database Files
4908 **
4909 ** ^(If this global variable is made to point to a string which is
4910 ** the name of a folder (a.k.a. directory), then all database files
4911 ** specified with a relative pathname and created or accessed by
4912 ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
4913 ** to be relative to that directory.)^ ^If this variable is a NULL
4914 ** pointer, then SQLite assumes that all database files specified
4915 ** with a relative pathname are relative to the current directory
4916 ** for the process.  Only the windows VFS makes use of this global
4917 ** variable; it is ignored by the unix VFS.
4918 **
4919 ** Changing the value of this variable while a database connection is
4920 ** open can result in a corrupt database.
4921 **
4922 ** It is not safe to read or modify this variable in more than one
4923 ** thread at a time.  It is not safe to read or modify this variable
4924 ** if a [database connection] is being used at the same time in a separate
4925 ** thread.
4926 ** It is intended that this variable be set once
4927 ** as part of process initialization and before any SQLite interface
4928 ** routines have been called and that this variable remain unchanged
4929 ** thereafter.
4930 **
4931 ** ^The [data_store_directory pragma] may modify this variable and cause
4932 ** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
4933 ** the [data_store_directory pragma] always assumes that any string
4934 ** that this variable points to is held in memory obtained from
4935 ** [sqlite3_malloc] and the pragma may attempt to free that memory
4936 ** using [sqlite3_free].
4937 ** Hence, if this variable is modified directly, either it should be
4938 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
4939 ** or else the use of the [data_store_directory pragma] should be avoided.
4940 */
4941 SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
4942 
4943 /*
4944 ** CAPI3REF: Test For Auto-Commit Mode
4945 ** KEYWORDS: {autocommit mode}
4946 ** METHOD: sqlite3
4947 **
4948 ** ^The sqlite3_get_autocommit() interface returns non-zero or
4949 ** zero if the given database connection is or is not in autocommit mode,
4950 ** respectively.  ^Autocommit mode is on by default.
4951 ** ^Autocommit mode is disabled by a [BEGIN] statement.
4952 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
4953 **
4954 ** If certain kinds of errors occur on a statement within a multi-statement
4955 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
4956 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
4957 ** transaction might be rolled back automatically.  The only way to
4958 ** find out whether SQLite automatically rolled back the transaction after
4959 ** an error is to use this function.
4960 **
4961 ** If another thread changes the autocommit status of the database
4962 ** connection while this routine is running, then the return value
4963 ** is undefined.
4964 */
4965 SQLITE_API int SQLITE_STDCALL sqlite3_get_autocommit(sqlite3*);
4966 
4967 /*
4968 ** CAPI3REF: Find The Database Handle Of A Prepared Statement
4969 ** METHOD: sqlite3_stmt
4970 **
4971 ** ^The sqlite3_db_handle interface returns the [database connection] handle
4972 ** to which a [prepared statement] belongs.  ^The [database connection]
4973 ** returned by sqlite3_db_handle is the same [database connection]
4974 ** that was the first argument
4975 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
4976 ** create the statement in the first place.
4977 */
4978 SQLITE_API sqlite3 *SQLITE_STDCALL sqlite3_db_handle(sqlite3_stmt*);
4979 
4980 /*
4981 ** CAPI3REF: Return The Filename For A Database Connection
4982 ** METHOD: sqlite3
4983 **
4984 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
4985 ** associated with database N of connection D.  ^The main database file
4986 ** has the name "main".  If there is no attached database N on the database
4987 ** connection D, or if database N is a temporary or in-memory database, then
4988 ** a NULL pointer is returned.
4989 **
4990 ** ^The filename returned by this function is the output of the
4991 ** xFullPathname method of the [VFS].  ^In other words, the filename
4992 ** will be an absolute pathname, even if the filename used
4993 ** to open the database originally was a URI or relative pathname.
4994 */
4995 SQLITE_API const char *SQLITE_STDCALL sqlite3_db_filename(sqlite3 *db, const char *zDbName);
4996 
4997 /*
4998 ** CAPI3REF: Determine if a database is read-only
4999 ** METHOD: sqlite3
5000 **
5001 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
5002 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not
5003 ** the name of a database on connection D.
5004 */
5005 SQLITE_API int SQLITE_STDCALL sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
5006 
5007 /*
5008 ** CAPI3REF: Find the next prepared statement
5009 ** METHOD: sqlite3
5010 **
5011 ** ^This interface returns a pointer to the next [prepared statement] after
5012 ** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
5013 ** then this interface returns a pointer to the first prepared statement
5014 ** associated with the database connection pDb.  ^If no prepared statement
5015 ** satisfies the conditions of this routine, it returns NULL.
5016 **
5017 ** The [database connection] pointer D in a call to
5018 ** [sqlite3_next_stmt(D,S)] must refer to an open database
5019 ** connection and in particular must not be a NULL pointer.
5020 */
5021 SQLITE_API sqlite3_stmt *SQLITE_STDCALL sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
5022 
5023 /*
5024 ** CAPI3REF: Commit And Rollback Notification Callbacks
5025 ** METHOD: sqlite3
5026 **
5027 ** ^The sqlite3_commit_hook() interface registers a callback
5028 ** function to be invoked whenever a transaction is [COMMIT | committed].
5029 ** ^Any callback set by a previous call to sqlite3_commit_hook()
5030 ** for the same database connection is overridden.
5031 ** ^The sqlite3_rollback_hook() interface registers a callback
5032 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
5033 ** ^Any callback set by a previous call to sqlite3_rollback_hook()
5034 ** for the same database connection is overridden.
5035 ** ^The pArg argument is passed through to the callback.
5036 ** ^If the callback on a commit hook function returns non-zero,
5037 ** then the commit is converted into a rollback.
5038 **
5039 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
5040 ** return the P argument from the previous call of the same function
5041 ** on the same [database connection] D, or NULL for
5042 ** the first call for each function on D.
5043 **
5044 ** The commit and rollback hook callbacks are not reentrant.
5045 ** The callback implementation must not do anything that will modify
5046 ** the database connection that invoked the callback.  Any actions
5047 ** to modify the database connection must be deferred until after the
5048 ** completion of the [sqlite3_step()] call that triggered the commit
5049 ** or rollback hook in the first place.
5050 ** Note that running any other SQL statements, including SELECT statements,
5051 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
5052 ** the database connections for the meaning of "modify" in this paragraph.
5053 **
5054 ** ^Registering a NULL function disables the callback.
5055 **
5056 ** ^When the commit hook callback routine returns zero, the [COMMIT]
5057 ** operation is allowed to continue normally.  ^If the commit hook
5058 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
5059 ** ^The rollback hook is invoked on a rollback that results from a commit
5060 ** hook returning non-zero, just as it would be with any other rollback.
5061 **
5062 ** ^For the purposes of this API, a transaction is said to have been
5063 ** rolled back if an explicit "ROLLBACK" statement is executed, or
5064 ** an error or constraint causes an implicit rollback to occur.
5065 ** ^The rollback callback is not invoked if a transaction is
5066 ** automatically rolled back because the database connection is closed.
5067 **
5068 ** See also the [sqlite3_update_hook()] interface.
5069 */
5070 SQLITE_API void *SQLITE_STDCALL sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
5071 SQLITE_API void *SQLITE_STDCALL sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
5072 
5073 /*
5074 ** CAPI3REF: Data Change Notification Callbacks
5075 ** METHOD: sqlite3
5076 **
5077 ** ^The sqlite3_update_hook() interface registers a callback function
5078 ** with the [database connection] identified by the first argument
5079 ** to be invoked whenever a row is updated, inserted or deleted in
5080 ** a rowid table.
5081 ** ^Any callback set by a previous call to this function
5082 ** for the same database connection is overridden.
5083 **
5084 ** ^The second argument is a pointer to the function to invoke when a
5085 ** row is updated, inserted or deleted in a rowid table.
5086 ** ^The first argument to the callback is a copy of the third argument
5087 ** to sqlite3_update_hook().
5088 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
5089 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
5090 ** to be invoked.
5091 ** ^The third and fourth arguments to the callback contain pointers to the
5092 ** database and table name containing the affected row.
5093 ** ^The final callback parameter is the [rowid] of the row.
5094 ** ^In the case of an update, this is the [rowid] after the update takes place.
5095 **
5096 ** ^(The update hook is not invoked when internal system tables are
5097 ** modified (i.e. sqlite_master and sqlite_sequence).)^
5098 ** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
5099 **
5100 ** ^In the current implementation, the update hook
5101 ** is not invoked when duplication rows are deleted because of an
5102 ** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
5103 ** invoked when rows are deleted using the [truncate optimization].
5104 ** The exceptions defined in this paragraph might change in a future
5105 ** release of SQLite.
5106 **
5107 ** The update hook implementation must not do anything that will modify
5108 ** the database connection that invoked the update hook.  Any actions
5109 ** to modify the database connection must be deferred until after the
5110 ** completion of the [sqlite3_step()] call that triggered the update hook.
5111 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
5112 ** database connections for the meaning of "modify" in this paragraph.
5113 **
5114 ** ^The sqlite3_update_hook(D,C,P) function
5115 ** returns the P argument from the previous call
5116 ** on the same [database connection] D, or NULL for
5117 ** the first call on D.
5118 **
5119 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()]
5120 ** interfaces.
5121 */
5122 SQLITE_API void *SQLITE_STDCALL sqlite3_update_hook(
5123   sqlite3*,
5124   void(*)(void *,int ,char const *,char const *,sqlite3_int64),
5125   void*
5126 );
5127 
5128 /*
5129 ** CAPI3REF: Enable Or Disable Shared Pager Cache
5130 **
5131 ** ^(This routine enables or disables the sharing of the database cache
5132 ** and schema data structures between [database connection | connections]
5133 ** to the same database. Sharing is enabled if the argument is true
5134 ** and disabled if the argument is false.)^
5135 **
5136 ** ^Cache sharing is enabled and disabled for an entire process.
5137 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite,
5138 ** sharing was enabled or disabled for each thread separately.
5139 **
5140 ** ^(The cache sharing mode set by this interface effects all subsequent
5141 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
5142 ** Existing database connections continue use the sharing mode
5143 ** that was in effect at the time they were opened.)^
5144 **
5145 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
5146 ** successfully.  An [error code] is returned otherwise.)^
5147 **
5148 ** ^Shared cache is disabled by default. But this might change in
5149 ** future releases of SQLite.  Applications that care about shared
5150 ** cache setting should set it explicitly.
5151 **
5152 ** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
5153 ** and will always return SQLITE_MISUSE. On those systems,
5154 ** shared cache mode should be enabled per-database connection via
5155 ** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
5156 **
5157 ** This interface is threadsafe on processors where writing a
5158 ** 32-bit integer is atomic.
5159 **
5160 ** See Also:  [SQLite Shared-Cache Mode]
5161 */
5162 SQLITE_API int SQLITE_STDCALL sqlite3_enable_shared_cache(int);
5163 
5164 /*
5165 ** CAPI3REF: Attempt To Free Heap Memory
5166 **
5167 ** ^The sqlite3_release_memory() interface attempts to free N bytes
5168 ** of heap memory by deallocating non-essential memory allocations
5169 ** held by the database library.   Memory used to cache database
5170 ** pages to improve performance is an example of non-essential memory.
5171 ** ^sqlite3_release_memory() returns the number of bytes actually freed,
5172 ** which might be more or less than the amount requested.
5173 ** ^The sqlite3_release_memory() routine is a no-op returning zero
5174 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5175 **
5176 ** See also: [sqlite3_db_release_memory()]
5177 */
5178 SQLITE_API int SQLITE_STDCALL sqlite3_release_memory(int);
5179 
5180 /*
5181 ** CAPI3REF: Free Memory Used By A Database Connection
5182 ** METHOD: sqlite3
5183 **
5184 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
5185 ** memory as possible from database connection D. Unlike the
5186 ** [sqlite3_release_memory()] interface, this interface is in effect even
5187 ** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
5188 ** omitted.
5189 **
5190 ** See also: [sqlite3_release_memory()]
5191 */
5192 SQLITE_API int SQLITE_STDCALL sqlite3_db_release_memory(sqlite3*);
5193 
5194 /*
5195 ** CAPI3REF: Impose A Limit On Heap Size
5196 **
5197 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
5198 ** soft limit on the amount of heap memory that may be allocated by SQLite.
5199 ** ^SQLite strives to keep heap memory utilization below the soft heap
5200 ** limit by reducing the number of pages held in the page cache
5201 ** as heap memory usages approaches the limit.
5202 ** ^The soft heap limit is "soft" because even though SQLite strives to stay
5203 ** below the limit, it will exceed the limit rather than generate
5204 ** an [SQLITE_NOMEM] error.  In other words, the soft heap limit
5205 ** is advisory only.
5206 **
5207 ** ^The return value from sqlite3_soft_heap_limit64() is the size of
5208 ** the soft heap limit prior to the call, or negative in the case of an
5209 ** error.  ^If the argument N is negative
5210 ** then no change is made to the soft heap limit.  Hence, the current
5211 ** size of the soft heap limit can be determined by invoking
5212 ** sqlite3_soft_heap_limit64() with a negative argument.
5213 **
5214 ** ^If the argument N is zero then the soft heap limit is disabled.
5215 **
5216 ** ^(The soft heap limit is not enforced in the current implementation
5217 ** if one or more of following conditions are true:
5218 **
5219 ** <ul>
5220 ** <li> The soft heap limit is set to zero.
5221 ** <li> Memory accounting is disabled using a combination of the
5222 **      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
5223 **      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
5224 ** <li> An alternative page cache implementation is specified using
5225 **      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
5226 ** <li> The page cache allocates from its own memory pool supplied
5227 **      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
5228 **      from the heap.
5229 ** </ul>)^
5230 **
5231 ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
5232 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
5233 ** compile-time option is invoked.  With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
5234 ** the soft heap limit is enforced on every memory allocation.  Without
5235 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
5236 ** when memory is allocated by the page cache.  Testing suggests that because
5237 ** the page cache is the predominate memory user in SQLite, most
5238 ** applications will achieve adequate soft heap limit enforcement without
5239 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
5240 **
5241 ** The circumstances under which SQLite will enforce the soft heap limit may
5242 ** changes in future releases of SQLite.
5243 */
5244 SQLITE_API sqlite3_int64 SQLITE_STDCALL sqlite3_soft_heap_limit64(sqlite3_int64 N);
5245 
5246 /*
5247 ** CAPI3REF: Deprecated Soft Heap Limit Interface
5248 ** DEPRECATED
5249 **
5250 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
5251 ** interface.  This routine is provided for historical compatibility
5252 ** only.  All new applications should use the
5253 ** [sqlite3_soft_heap_limit64()] interface rather than this one.
5254 */
5255 SQLITE_API SQLITE_DEPRECATED void SQLITE_STDCALL sqlite3_soft_heap_limit(int N);
5256 
5257 
5258 /*
5259 ** CAPI3REF: Extract Metadata About A Column Of A Table
5260 ** METHOD: sqlite3
5261 **
5262 ** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
5263 ** information about column C of table T in database D
5264 ** on [database connection] X.)^  ^The sqlite3_table_column_metadata()
5265 ** interface returns SQLITE_OK and fills in the non-NULL pointers in
5266 ** the final five arguments with appropriate values if the specified
5267 ** column exists.  ^The sqlite3_table_column_metadata() interface returns
5268 ** SQLITE_ERROR and if the specified column does not exist.
5269 ** ^If the column-name parameter to sqlite3_table_column_metadata() is a
5270 ** NULL pointer, then this routine simply checks for the existance of the
5271 ** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
5272 ** does not.
5273 **
5274 ** ^The column is identified by the second, third and fourth parameters to
5275 ** this function. ^(The second parameter is either the name of the database
5276 ** (i.e. "main", "temp", or an attached database) containing the specified
5277 ** table or NULL.)^ ^If it is NULL, then all attached databases are searched
5278 ** for the table using the same algorithm used by the database engine to
5279 ** resolve unqualified table references.
5280 **
5281 ** ^The third and fourth parameters to this function are the table and column
5282 ** name of the desired column, respectively.
5283 **
5284 ** ^Metadata is returned by writing to the memory locations passed as the 5th
5285 ** and subsequent parameters to this function. ^Any of these arguments may be
5286 ** NULL, in which case the corresponding element of metadata is omitted.
5287 **
5288 ** ^(<blockquote>
5289 ** <table border="1">
5290 ** <tr><th> Parameter <th> Output<br>Type <th>  Description
5291 **
5292 ** <tr><td> 5th <td> const char* <td> Data type
5293 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
5294 ** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
5295 ** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
5296 ** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
5297 ** </table>
5298 ** </blockquote>)^
5299 **
5300 ** ^The memory pointed to by the character pointers returned for the
5301 ** declaration type and collation sequence is valid until the next
5302 ** call to any SQLite API function.
5303 **
5304 ** ^If the specified table is actually a view, an [error code] is returned.
5305 **
5306 ** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
5307 ** is not a [WITHOUT ROWID] table and an
5308 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
5309 ** parameters are set for the explicitly declared column. ^(If there is no
5310 ** [INTEGER PRIMARY KEY] column, then the outputs
5311 ** for the [rowid] are set as follows:
5312 **
5313 ** <pre>
5314 **     data type: "INTEGER"
5315 **     collation sequence: "BINARY"
5316 **     not null: 0
5317 **     primary key: 1
5318 **     auto increment: 0
5319 ** </pre>)^
5320 **
5321 ** ^This function causes all database schemas to be read from disk and
5322 ** parsed, if that has not already been done, and returns an error if
5323 ** any errors are encountered while loading the schema.
5324 */
5325 SQLITE_API int SQLITE_STDCALL sqlite3_table_column_metadata(
5326   sqlite3 *db,                /* Connection handle */
5327   const char *zDbName,        /* Database name or NULL */
5328   const char *zTableName,     /* Table name */
5329   const char *zColumnName,    /* Column name */
5330   char const **pzDataType,    /* OUTPUT: Declared data type */
5331   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
5332   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
5333   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
5334   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
5335 );
5336 
5337 /*
5338 ** CAPI3REF: Load An Extension
5339 ** METHOD: sqlite3
5340 **
5341 ** ^This interface loads an SQLite extension library from the named file.
5342 **
5343 ** ^The sqlite3_load_extension() interface attempts to load an
5344 ** [SQLite extension] library contained in the file zFile.  If
5345 ** the file cannot be loaded directly, attempts are made to load
5346 ** with various operating-system specific extensions added.
5347 ** So for example, if "samplelib" cannot be loaded, then names like
5348 ** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
5349 ** be tried also.
5350 **
5351 ** ^The entry point is zProc.
5352 ** ^(zProc may be 0, in which case SQLite will try to come up with an
5353 ** entry point name on its own.  It first tries "sqlite3_extension_init".
5354 ** If that does not work, it constructs a name "sqlite3_X_init" where the
5355 ** X is consists of the lower-case equivalent of all ASCII alphabetic
5356 ** characters in the filename from the last "/" to the first following
5357 ** "." and omitting any initial "lib".)^
5358 ** ^The sqlite3_load_extension() interface returns
5359 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
5360 ** ^If an error occurs and pzErrMsg is not 0, then the
5361 ** [sqlite3_load_extension()] interface shall attempt to
5362 ** fill *pzErrMsg with error message text stored in memory
5363 ** obtained from [sqlite3_malloc()]. The calling function
5364 ** should free this memory by calling [sqlite3_free()].
5365 **
5366 ** ^Extension loading must be enabled using
5367 ** [sqlite3_enable_load_extension()] prior to calling this API,
5368 ** otherwise an error will be returned.
5369 **
5370 ** See also the [load_extension() SQL function].
5371 */
5372 SQLITE_API int SQLITE_STDCALL sqlite3_load_extension(
5373   sqlite3 *db,          /* Load the extension into this database connection */
5374   const char *zFile,    /* Name of the shared library containing extension */
5375   const char *zProc,    /* Entry point.  Derived from zFile if 0 */
5376   char **pzErrMsg       /* Put error message here if not 0 */
5377 );
5378 
5379 /*
5380 ** CAPI3REF: Enable Or Disable Extension Loading
5381 ** METHOD: sqlite3
5382 **
5383 ** ^So as not to open security holes in older applications that are
5384 ** unprepared to deal with [extension loading], and as a means of disabling
5385 ** [extension loading] while evaluating user-entered SQL, the following API
5386 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
5387 **
5388 ** ^Extension loading is off by default.
5389 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
5390 ** to turn extension loading on and call it with onoff==0 to turn
5391 ** it back off again.
5392 */
5393 SQLITE_API int SQLITE_STDCALL sqlite3_enable_load_extension(sqlite3 *db, int onoff);
5394 
5395 /*
5396 ** CAPI3REF: Automatically Load Statically Linked Extensions
5397 **
5398 ** ^This interface causes the xEntryPoint() function to be invoked for
5399 ** each new [database connection] that is created.  The idea here is that
5400 ** xEntryPoint() is the entry point for a statically linked [SQLite extension]
5401 ** that is to be automatically loaded into all new database connections.
5402 **
5403 ** ^(Even though the function prototype shows that xEntryPoint() takes
5404 ** no arguments and returns void, SQLite invokes xEntryPoint() with three
5405 ** arguments and expects and integer result as if the signature of the
5406 ** entry point where as follows:
5407 **
5408 ** <blockquote><pre>
5409 ** &nbsp;  int xEntryPoint(
5410 ** &nbsp;    sqlite3 *db,
5411 ** &nbsp;    const char **pzErrMsg,
5412 ** &nbsp;    const struct sqlite3_api_routines *pThunk
5413 ** &nbsp;  );
5414 ** </pre></blockquote>)^
5415 **
5416 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
5417 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
5418 ** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
5419 ** is NULL before calling the xEntryPoint().  ^SQLite will invoke
5420 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
5421 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
5422 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
5423 **
5424 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
5425 ** on the list of automatic extensions is a harmless no-op. ^No entry point
5426 ** will be called more than once for each database connection that is opened.
5427 **
5428 ** See also: [sqlite3_reset_auto_extension()]
5429 ** and [sqlite3_cancel_auto_extension()]
5430 */
5431 SQLITE_API int SQLITE_STDCALL sqlite3_auto_extension(void (*xEntryPoint)(void));
5432 
5433 /*
5434 ** CAPI3REF: Cancel Automatic Extension Loading
5435 **
5436 ** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
5437 ** initialization routine X that was registered using a prior call to
5438 ** [sqlite3_auto_extension(X)].  ^The [sqlite3_cancel_auto_extension(X)]
5439 ** routine returns 1 if initialization routine X was successfully
5440 ** unregistered and it returns 0 if X was not on the list of initialization
5441 ** routines.
5442 */
5443 SQLITE_API int SQLITE_STDCALL sqlite3_cancel_auto_extension(void (*xEntryPoint)(void));
5444 
5445 /*
5446 ** CAPI3REF: Reset Automatic Extension Loading
5447 **
5448 ** ^This interface disables all automatic extensions previously
5449 ** registered using [sqlite3_auto_extension()].
5450 */
5451 SQLITE_API void SQLITE_STDCALL sqlite3_reset_auto_extension(void);
5452 
5453 /*
5454 ** The interface to the virtual-table mechanism is currently considered
5455 ** to be experimental.  The interface might change in incompatible ways.
5456 ** If this is a problem for you, do not use the interface at this time.
5457 **
5458 ** When the virtual-table mechanism stabilizes, we will declare the
5459 ** interface fixed, support it indefinitely, and remove this comment.
5460 */
5461 
5462 /*
5463 ** Structures used by the virtual table interface
5464 */
5465 typedef struct sqlite3_vtab sqlite3_vtab;
5466 typedef struct sqlite3_index_info sqlite3_index_info;
5467 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
5468 typedef struct sqlite3_module sqlite3_module;
5469 
5470 /*
5471 ** CAPI3REF: Virtual Table Object
5472 ** KEYWORDS: sqlite3_module {virtual table module}
5473 **
5474 ** This structure, sometimes called a "virtual table module",
5475 ** defines the implementation of a [virtual tables].
5476 ** This structure consists mostly of methods for the module.
5477 **
5478 ** ^A virtual table module is created by filling in a persistent
5479 ** instance of this structure and passing a pointer to that instance
5480 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
5481 ** ^The registration remains valid until it is replaced by a different
5482 ** module or until the [database connection] closes.  The content
5483 ** of this structure must not change while it is registered with
5484 ** any database connection.
5485 */
5486 struct sqlite3_module {
5487   int iVersion;
5488   int (*xCreate)(sqlite3*, void *pAux,
5489                int argc, const char *const*argv,
5490                sqlite3_vtab **ppVTab, char**);
5491   int (*xConnect)(sqlite3*, void *pAux,
5492                int argc, const char *const*argv,
5493                sqlite3_vtab **ppVTab, char**);
5494   int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
5495   int (*xDisconnect)(sqlite3_vtab *pVTab);
5496   int (*xDestroy)(sqlite3_vtab *pVTab);
5497   int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
5498   int (*xClose)(sqlite3_vtab_cursor*);
5499   int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
5500                 int argc, sqlite3_value **argv);
5501   int (*xNext)(sqlite3_vtab_cursor*);
5502   int (*xEof)(sqlite3_vtab_cursor*);
5503   int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
5504   int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
5505   int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
5506   int (*xBegin)(sqlite3_vtab *pVTab);
5507   int (*xSync)(sqlite3_vtab *pVTab);
5508   int (*xCommit)(sqlite3_vtab *pVTab);
5509   int (*xRollback)(sqlite3_vtab *pVTab);
5510   int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
5511                        void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
5512                        void **ppArg);
5513   int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
5514   /* The methods above are in version 1 of the sqlite_module object. Those
5515   ** below are for version 2 and greater. */
5516   int (*xSavepoint)(sqlite3_vtab *pVTab, int);
5517   int (*xRelease)(sqlite3_vtab *pVTab, int);
5518   int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
5519 };
5520 
5521 /*
5522 ** CAPI3REF: Virtual Table Indexing Information
5523 ** KEYWORDS: sqlite3_index_info
5524 **
5525 ** The sqlite3_index_info structure and its substructures is used as part
5526 ** of the [virtual table] interface to
5527 ** pass information into and receive the reply from the [xBestIndex]
5528 ** method of a [virtual table module].  The fields under **Inputs** are the
5529 ** inputs to xBestIndex and are read-only.  xBestIndex inserts its
5530 ** results into the **Outputs** fields.
5531 **
5532 ** ^(The aConstraint[] array records WHERE clause constraints of the form:
5533 **
5534 ** <blockquote>column OP expr</blockquote>
5535 **
5536 ** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^  ^(The particular operator is
5537 ** stored in aConstraint[].op using one of the
5538 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
5539 ** ^(The index of the column is stored in
5540 ** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
5541 ** expr on the right-hand side can be evaluated (and thus the constraint
5542 ** is usable) and false if it cannot.)^
5543 **
5544 ** ^The optimizer automatically inverts terms of the form "expr OP column"
5545 ** and makes other simplifications to the WHERE clause in an attempt to
5546 ** get as many WHERE clause terms into the form shown above as possible.
5547 ** ^The aConstraint[] array only reports WHERE clause terms that are
5548 ** relevant to the particular virtual table being queried.
5549 **
5550 ** ^Information about the ORDER BY clause is stored in aOrderBy[].
5551 ** ^Each term of aOrderBy records a column of the ORDER BY clause.
5552 **
5553 ** The [xBestIndex] method must fill aConstraintUsage[] with information
5554 ** about what parameters to pass to xFilter.  ^If argvIndex>0 then
5555 ** the right-hand side of the corresponding aConstraint[] is evaluated
5556 ** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
5557 ** is true, then the constraint is assumed to be fully handled by the
5558 ** virtual table and is not checked again by SQLite.)^
5559 **
5560 ** ^The idxNum and idxPtr values are recorded and passed into the
5561 ** [xFilter] method.
5562 ** ^[sqlite3_free()] is used to free idxPtr if and only if
5563 ** needToFreeIdxPtr is true.
5564 **
5565 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
5566 ** the correct order to satisfy the ORDER BY clause so that no separate
5567 ** sorting step is required.
5568 **
5569 ** ^The estimatedCost value is an estimate of the cost of a particular
5570 ** strategy. A cost of N indicates that the cost of the strategy is similar
5571 ** to a linear scan of an SQLite table with N rows. A cost of log(N)
5572 ** indicates that the expense of the operation is similar to that of a
5573 ** binary search on a unique indexed field of an SQLite table with N rows.
5574 **
5575 ** ^The estimatedRows value is an estimate of the number of rows that
5576 ** will be returned by the strategy.
5577 **
5578 ** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
5579 ** structure for SQLite version 3.8.2. If a virtual table extension is
5580 ** used with an SQLite version earlier than 3.8.2, the results of attempting
5581 ** to read or write the estimatedRows field are undefined (but are likely
5582 ** to included crashing the application). The estimatedRows field should
5583 ** therefore only be used if [sqlite3_libversion_number()] returns a
5584 ** value greater than or equal to 3008002.
5585 */
5586 struct sqlite3_index_info {
5587   /* Inputs */
5588   int nConstraint;           /* Number of entries in aConstraint */
5589   struct sqlite3_index_constraint {
5590      int iColumn;              /* Column on left-hand side of constraint */
5591      unsigned char op;         /* Constraint operator */
5592      unsigned char usable;     /* True if this constraint is usable */
5593      int iTermOffset;          /* Used internally - xBestIndex should ignore */
5594   } *aConstraint;            /* Table of WHERE clause constraints */
5595   int nOrderBy;              /* Number of terms in the ORDER BY clause */
5596   struct sqlite3_index_orderby {
5597      int iColumn;              /* Column number */
5598      unsigned char desc;       /* True for DESC.  False for ASC. */
5599   } *aOrderBy;               /* The ORDER BY clause */
5600   /* Outputs */
5601   struct sqlite3_index_constraint_usage {
5602     int argvIndex;           /* if >0, constraint is part of argv to xFilter */
5603     unsigned char omit;      /* Do not code a test for this constraint */
5604   } *aConstraintUsage;
5605   int idxNum;                /* Number used to identify the index */
5606   char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
5607   int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
5608   int orderByConsumed;       /* True if output is already ordered */
5609   double estimatedCost;           /* Estimated cost of using this index */
5610   /* Fields below are only available in SQLite 3.8.2 and later */
5611   sqlite3_int64 estimatedRows;    /* Estimated number of rows returned */
5612 };
5613 
5614 /*
5615 ** CAPI3REF: Virtual Table Constraint Operator Codes
5616 **
5617 ** These macros defined the allowed values for the
5618 ** [sqlite3_index_info].aConstraint[].op field.  Each value represents
5619 ** an operator that is part of a constraint term in the wHERE clause of
5620 ** a query that uses a [virtual table].
5621 */
5622 #define SQLITE_INDEX_CONSTRAINT_EQ    2
5623 #define SQLITE_INDEX_CONSTRAINT_GT    4
5624 #define SQLITE_INDEX_CONSTRAINT_LE    8
5625 #define SQLITE_INDEX_CONSTRAINT_LT    16
5626 #define SQLITE_INDEX_CONSTRAINT_GE    32
5627 #define SQLITE_INDEX_CONSTRAINT_MATCH 64
5628 
5629 /*
5630 ** CAPI3REF: Register A Virtual Table Implementation
5631 ** METHOD: sqlite3
5632 **
5633 ** ^These routines are used to register a new [virtual table module] name.
5634 ** ^Module names must be registered before
5635 ** creating a new [virtual table] using the module and before using a
5636 ** preexisting [virtual table] for the module.
5637 **
5638 ** ^The module name is registered on the [database connection] specified
5639 ** by the first parameter.  ^The name of the module is given by the
5640 ** second parameter.  ^The third parameter is a pointer to
5641 ** the implementation of the [virtual table module].   ^The fourth
5642 ** parameter is an arbitrary client data pointer that is passed through
5643 ** into the [xCreate] and [xConnect] methods of the virtual table module
5644 ** when a new virtual table is be being created or reinitialized.
5645 **
5646 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
5647 ** is a pointer to a destructor for the pClientData.  ^SQLite will
5648 ** invoke the destructor function (if it is not NULL) when SQLite
5649 ** no longer needs the pClientData pointer.  ^The destructor will also
5650 ** be invoked if the call to sqlite3_create_module_v2() fails.
5651 ** ^The sqlite3_create_module()
5652 ** interface is equivalent to sqlite3_create_module_v2() with a NULL
5653 ** destructor.
5654 */
5655 SQLITE_API int SQLITE_STDCALL sqlite3_create_module(
5656   sqlite3 *db,               /* SQLite connection to register module with */
5657   const char *zName,         /* Name of the module */
5658   const sqlite3_module *p,   /* Methods for the module */
5659   void *pClientData          /* Client data for xCreate/xConnect */
5660 );
5661 SQLITE_API int SQLITE_STDCALL sqlite3_create_module_v2(
5662   sqlite3 *db,               /* SQLite connection to register module with */
5663   const char *zName,         /* Name of the module */
5664   const sqlite3_module *p,   /* Methods for the module */
5665   void *pClientData,         /* Client data for xCreate/xConnect */
5666   void(*xDestroy)(void*)     /* Module destructor function */
5667 );
5668 
5669 /*
5670 ** CAPI3REF: Virtual Table Instance Object
5671 ** KEYWORDS: sqlite3_vtab
5672 **
5673 ** Every [virtual table module] implementation uses a subclass
5674 ** of this object to describe a particular instance
5675 ** of the [virtual table].  Each subclass will
5676 ** be tailored to the specific needs of the module implementation.
5677 ** The purpose of this superclass is to define certain fields that are
5678 ** common to all module implementations.
5679 **
5680 ** ^Virtual tables methods can set an error message by assigning a
5681 ** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
5682 ** take care that any prior string is freed by a call to [sqlite3_free()]
5683 ** prior to assigning a new string to zErrMsg.  ^After the error message
5684 ** is delivered up to the client application, the string will be automatically
5685 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
5686 */
5687 struct sqlite3_vtab {
5688   const sqlite3_module *pModule;  /* The module for this virtual table */
5689   int nRef;                       /* Number of open cursors */
5690   char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
5691   /* Virtual table implementations will typically add additional fields */
5692 };
5693 
5694 /*
5695 ** CAPI3REF: Virtual Table Cursor Object
5696 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
5697 **
5698 ** Every [virtual table module] implementation uses a subclass of the
5699 ** following structure to describe cursors that point into the
5700 ** [virtual table] and are used
5701 ** to loop through the virtual table.  Cursors are created using the
5702 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
5703 ** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
5704 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
5705 ** of the module.  Each module implementation will define
5706 ** the content of a cursor structure to suit its own needs.
5707 **
5708 ** This superclass exists in order to define fields of the cursor that
5709 ** are common to all implementations.
5710 */
5711 struct sqlite3_vtab_cursor {
5712   sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
5713   /* Virtual table implementations will typically add additional fields */
5714 };
5715 
5716 /*
5717 ** CAPI3REF: Declare The Schema Of A Virtual Table
5718 **
5719 ** ^The [xCreate] and [xConnect] methods of a
5720 ** [virtual table module] call this interface
5721 ** to declare the format (the names and datatypes of the columns) of
5722 ** the virtual tables they implement.
5723 */
5724 SQLITE_API int SQLITE_STDCALL sqlite3_declare_vtab(sqlite3*, const char *zSQL);
5725 
5726 /*
5727 ** CAPI3REF: Overload A Function For A Virtual Table
5728 ** METHOD: sqlite3
5729 **
5730 ** ^(Virtual tables can provide alternative implementations of functions
5731 ** using the [xFindFunction] method of the [virtual table module].
5732 ** But global versions of those functions
5733 ** must exist in order to be overloaded.)^
5734 **
5735 ** ^(This API makes sure a global version of a function with a particular
5736 ** name and number of parameters exists.  If no such function exists
5737 ** before this API is called, a new function is created.)^  ^The implementation
5738 ** of the new function always causes an exception to be thrown.  So
5739 ** the new function is not good for anything by itself.  Its only
5740 ** purpose is to be a placeholder function that can be overloaded
5741 ** by a [virtual table].
5742 */
5743 SQLITE_API int SQLITE_STDCALL sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
5744 
5745 /*
5746 ** The interface to the virtual-table mechanism defined above (back up
5747 ** to a comment remarkably similar to this one) is currently considered
5748 ** to be experimental.  The interface might change in incompatible ways.
5749 ** If this is a problem for you, do not use the interface at this time.
5750 **
5751 ** When the virtual-table mechanism stabilizes, we will declare the
5752 ** interface fixed, support it indefinitely, and remove this comment.
5753 */
5754 
5755 /*
5756 ** CAPI3REF: A Handle To An Open BLOB
5757 ** KEYWORDS: {BLOB handle} {BLOB handles}
5758 **
5759 ** An instance of this object represents an open BLOB on which
5760 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
5761 ** ^Objects of this type are created by [sqlite3_blob_open()]
5762 ** and destroyed by [sqlite3_blob_close()].
5763 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
5764 ** can be used to read or write small subsections of the BLOB.
5765 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
5766 */
5767 typedef struct sqlite3_blob sqlite3_blob;
5768 
5769 /*
5770 ** CAPI3REF: Open A BLOB For Incremental I/O
5771 ** METHOD: sqlite3
5772 ** CONSTRUCTOR: sqlite3_blob
5773 **
5774 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
5775 ** in row iRow, column zColumn, table zTable in database zDb;
5776 ** in other words, the same BLOB that would be selected by:
5777 **
5778 ** <pre>
5779 **     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
5780 ** </pre>)^
5781 **
5782 ** ^(Parameter zDb is not the filename that contains the database, but
5783 ** rather the symbolic name of the database. For attached databases, this is
5784 ** the name that appears after the AS keyword in the [ATTACH] statement.
5785 ** For the main database file, the database name is "main". For TEMP
5786 ** tables, the database name is "temp".)^
5787 **
5788 ** ^If the flags parameter is non-zero, then the BLOB is opened for read
5789 ** and write access. ^If the flags parameter is zero, the BLOB is opened for
5790 ** read-only access.
5791 **
5792 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
5793 ** in *ppBlob. Otherwise an [error code] is returned and, unless the error
5794 ** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
5795 ** the API is not misused, it is always safe to call [sqlite3_blob_close()]
5796 ** on *ppBlob after this function it returns.
5797 **
5798 ** This function fails with SQLITE_ERROR if any of the following are true:
5799 ** <ul>
5800 **   <li> ^(Database zDb does not exist)^,
5801 **   <li> ^(Table zTable does not exist within database zDb)^,
5802 **   <li> ^(Table zTable is a WITHOUT ROWID table)^,
5803 **   <li> ^(Column zColumn does not exist)^,
5804 **   <li> ^(Row iRow is not present in the table)^,
5805 **   <li> ^(The specified column of row iRow contains a value that is not
5806 **         a TEXT or BLOB value)^,
5807 **   <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
5808 **         constraint and the blob is being opened for read/write access)^,
5809 **   <li> ^([foreign key constraints | Foreign key constraints] are enabled,
5810 **         column zColumn is part of a [child key] definition and the blob is
5811 **         being opened for read/write access)^.
5812 ** </ul>
5813 **
5814 ** ^Unless it returns SQLITE_MISUSE, this function sets the
5815 ** [database connection] error code and message accessible via
5816 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
5817 **
5818 **
5819 ** ^(If the row that a BLOB handle points to is modified by an
5820 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
5821 ** then the BLOB handle is marked as "expired".
5822 ** This is true if any column of the row is changed, even a column
5823 ** other than the one the BLOB handle is open on.)^
5824 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
5825 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
5826 ** ^(Changes written into a BLOB prior to the BLOB expiring are not
5827 ** rolled back by the expiration of the BLOB.  Such changes will eventually
5828 ** commit if the transaction continues to completion.)^
5829 **
5830 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
5831 ** the opened blob.  ^The size of a blob may not be changed by this
5832 ** interface.  Use the [UPDATE] SQL command to change the size of a
5833 ** blob.
5834 **
5835 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
5836 ** and the built-in [zeroblob] SQL function may be used to create a
5837 ** zero-filled blob to read or write using the incremental-blob interface.
5838 **
5839 ** To avoid a resource leak, every open [BLOB handle] should eventually
5840 ** be released by a call to [sqlite3_blob_close()].
5841 */
5842 SQLITE_API int SQLITE_STDCALL sqlite3_blob_open(
5843   sqlite3*,
5844   const char *zDb,
5845   const char *zTable,
5846   const char *zColumn,
5847   sqlite3_int64 iRow,
5848   int flags,
5849   sqlite3_blob **ppBlob
5850 );
5851 
5852 /*
5853 ** CAPI3REF: Move a BLOB Handle to a New Row
5854 ** METHOD: sqlite3_blob
5855 **
5856 ** ^This function is used to move an existing blob handle so that it points
5857 ** to a different row of the same database table. ^The new row is identified
5858 ** by the rowid value passed as the second argument. Only the row can be
5859 ** changed. ^The database, table and column on which the blob handle is open
5860 ** remain the same. Moving an existing blob handle to a new row can be
5861 ** faster than closing the existing handle and opening a new one.
5862 **
5863 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
5864 ** it must exist and there must be either a blob or text value stored in
5865 ** the nominated column.)^ ^If the new row is not present in the table, or if
5866 ** it does not contain a blob or text value, or if another error occurs, an
5867 ** SQLite error code is returned and the blob handle is considered aborted.
5868 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
5869 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
5870 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
5871 ** always returns zero.
5872 **
5873 ** ^This function sets the database handle error code and message.
5874 */
5875 SQLITE_API SQLITE_EXPERIMENTAL int SQLITE_STDCALL sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
5876 
5877 /*
5878 ** CAPI3REF: Close A BLOB Handle
5879 ** DESTRUCTOR: sqlite3_blob
5880 **
5881 ** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
5882 ** unconditionally.  Even if this routine returns an error code, the
5883 ** handle is still closed.)^
5884 **
5885 ** ^If the blob handle being closed was opened for read-write access, and if
5886 ** the database is in auto-commit mode and there are no other open read-write
5887 ** blob handles or active write statements, the current transaction is
5888 ** committed. ^If an error occurs while committing the transaction, an error
5889 ** code is returned and the transaction rolled back.
5890 **
5891 ** Calling this function with an argument that is not a NULL pointer or an
5892 ** open blob handle results in undefined behaviour. ^Calling this routine
5893 ** with a null pointer (such as would be returned by a failed call to
5894 ** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
5895 ** is passed a valid open blob handle, the values returned by the
5896 ** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
5897 */
5898 SQLITE_API int SQLITE_STDCALL sqlite3_blob_close(sqlite3_blob *);
5899 
5900 /*
5901 ** CAPI3REF: Return The Size Of An Open BLOB
5902 ** METHOD: sqlite3_blob
5903 **
5904 ** ^Returns the size in bytes of the BLOB accessible via the
5905 ** successfully opened [BLOB handle] in its only argument.  ^The
5906 ** incremental blob I/O routines can only read or overwriting existing
5907 ** blob content; they cannot change the size of a blob.
5908 **
5909 ** This routine only works on a [BLOB handle] which has been created
5910 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5911 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
5912 ** to this routine results in undefined and probably undesirable behavior.
5913 */
5914 SQLITE_API int SQLITE_STDCALL sqlite3_blob_bytes(sqlite3_blob *);
5915 
5916 /*
5917 ** CAPI3REF: Read Data From A BLOB Incrementally
5918 ** METHOD: sqlite3_blob
5919 **
5920 ** ^(This function is used to read data from an open [BLOB handle] into a
5921 ** caller-supplied buffer. N bytes of data are copied into buffer Z
5922 ** from the open BLOB, starting at offset iOffset.)^
5923 **
5924 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5925 ** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
5926 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
5927 ** ^The size of the blob (and hence the maximum value of N+iOffset)
5928 ** can be determined using the [sqlite3_blob_bytes()] interface.
5929 **
5930 ** ^An attempt to read from an expired [BLOB handle] fails with an
5931 ** error code of [SQLITE_ABORT].
5932 **
5933 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
5934 ** Otherwise, an [error code] or an [extended error code] is returned.)^
5935 **
5936 ** This routine only works on a [BLOB handle] which has been created
5937 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5938 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
5939 ** to this routine results in undefined and probably undesirable behavior.
5940 **
5941 ** See also: [sqlite3_blob_write()].
5942 */
5943 SQLITE_API int SQLITE_STDCALL sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
5944 
5945 /*
5946 ** CAPI3REF: Write Data Into A BLOB Incrementally
5947 ** METHOD: sqlite3_blob
5948 **
5949 ** ^(This function is used to write data into an open [BLOB handle] from a
5950 ** caller-supplied buffer. N bytes of data are copied from the buffer Z
5951 ** into the open BLOB, starting at offset iOffset.)^
5952 **
5953 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
5954 ** Otherwise, an  [error code] or an [extended error code] is returned.)^
5955 ** ^Unless SQLITE_MISUSE is returned, this function sets the
5956 ** [database connection] error code and message accessible via
5957 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
5958 **
5959 ** ^If the [BLOB handle] passed as the first argument was not opened for
5960 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
5961 ** this function returns [SQLITE_READONLY].
5962 **
5963 ** This function may only modify the contents of the BLOB; it is
5964 ** not possible to increase the size of a BLOB using this API.
5965 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
5966 ** [SQLITE_ERROR] is returned and no data is written. The size of the
5967 ** BLOB (and hence the maximum value of N+iOffset) can be determined
5968 ** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
5969 ** than zero [SQLITE_ERROR] is returned and no data is written.
5970 **
5971 ** ^An attempt to write to an expired [BLOB handle] fails with an
5972 ** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
5973 ** before the [BLOB handle] expired are not rolled back by the
5974 ** expiration of the handle, though of course those changes might
5975 ** have been overwritten by the statement that expired the BLOB handle
5976 ** or by other independent statements.
5977 **
5978 ** This routine only works on a [BLOB handle] which has been created
5979 ** by a prior successful call to [sqlite3_blob_open()] and which has not
5980 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
5981 ** to this routine results in undefined and probably undesirable behavior.
5982 **
5983 ** See also: [sqlite3_blob_read()].
5984 */
5985 SQLITE_API int SQLITE_STDCALL sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
5986 
5987 /*
5988 ** CAPI3REF: Virtual File System Objects
5989 **
5990 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
5991 ** that SQLite uses to interact
5992 ** with the underlying operating system.  Most SQLite builds come with a
5993 ** single default VFS that is appropriate for the host computer.
5994 ** New VFSes can be registered and existing VFSes can be unregistered.
5995 ** The following interfaces are provided.
5996 **
5997 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
5998 ** ^Names are case sensitive.
5999 ** ^Names are zero-terminated UTF-8 strings.
6000 ** ^If there is no match, a NULL pointer is returned.
6001 ** ^If zVfsName is NULL then the default VFS is returned.
6002 **
6003 ** ^New VFSes are registered with sqlite3_vfs_register().
6004 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
6005 ** ^The same VFS can be registered multiple times without injury.
6006 ** ^To make an existing VFS into the default VFS, register it again
6007 ** with the makeDflt flag set.  If two different VFSes with the
6008 ** same name are registered, the behavior is undefined.  If a
6009 ** VFS is registered with a name that is NULL or an empty string,
6010 ** then the behavior is undefined.
6011 **
6012 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
6013 ** ^(If the default VFS is unregistered, another VFS is chosen as
6014 ** the default.  The choice for the new VFS is arbitrary.)^
6015 */
6016 SQLITE_API sqlite3_vfs *SQLITE_STDCALL sqlite3_vfs_find(const char *zVfsName);
6017 SQLITE_API int SQLITE_STDCALL sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
6018 SQLITE_API int SQLITE_STDCALL sqlite3_vfs_unregister(sqlite3_vfs*);
6019 
6020 /*
6021 ** CAPI3REF: Mutexes
6022 **
6023 ** The SQLite core uses these routines for thread
6024 ** synchronization. Though they are intended for internal
6025 ** use by SQLite, code that links against SQLite is
6026 ** permitted to use any of these routines.
6027 **
6028 ** The SQLite source code contains multiple implementations
6029 ** of these mutex routines.  An appropriate implementation
6030 ** is selected automatically at compile-time.  The following
6031 ** implementations are available in the SQLite core:
6032 **
6033 ** <ul>
6034 ** <li>   SQLITE_MUTEX_PTHREADS
6035 ** <li>   SQLITE_MUTEX_W32
6036 ** <li>   SQLITE_MUTEX_NOOP
6037 ** </ul>
6038 **
6039 ** The SQLITE_MUTEX_NOOP implementation is a set of routines
6040 ** that does no real locking and is appropriate for use in
6041 ** a single-threaded application.  The SQLITE_MUTEX_PTHREADS and
6042 ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
6043 ** and Windows.
6044 **
6045 ** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
6046 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
6047 ** implementation is included with the library. In this case the
6048 ** application must supply a custom mutex implementation using the
6049 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
6050 ** before calling sqlite3_initialize() or any other public sqlite3_
6051 ** function that calls sqlite3_initialize().
6052 **
6053 ** ^The sqlite3_mutex_alloc() routine allocates a new
6054 ** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
6055 ** routine returns NULL if it is unable to allocate the requested
6056 ** mutex.  The argument to sqlite3_mutex_alloc() must one of these
6057 ** integer constants:
6058 **
6059 ** <ul>
6060 ** <li>  SQLITE_MUTEX_FAST
6061 ** <li>  SQLITE_MUTEX_RECURSIVE
6062 ** <li>  SQLITE_MUTEX_STATIC_MASTER
6063 ** <li>  SQLITE_MUTEX_STATIC_MEM
6064 ** <li>  SQLITE_MUTEX_STATIC_OPEN
6065 ** <li>  SQLITE_MUTEX_STATIC_PRNG
6066 ** <li>  SQLITE_MUTEX_STATIC_LRU
6067 ** <li>  SQLITE_MUTEX_STATIC_PMEM
6068 ** <li>  SQLITE_MUTEX_STATIC_APP1
6069 ** <li>  SQLITE_MUTEX_STATIC_APP2
6070 ** <li>  SQLITE_MUTEX_STATIC_APP3
6071 ** </ul>
6072 **
6073 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
6074 ** cause sqlite3_mutex_alloc() to create
6075 ** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
6076 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
6077 ** The mutex implementation does not need to make a distinction
6078 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
6079 ** not want to.  SQLite will only request a recursive mutex in
6080 ** cases where it really needs one.  If a faster non-recursive mutex
6081 ** implementation is available on the host platform, the mutex subsystem
6082 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
6083 **
6084 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
6085 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
6086 ** a pointer to a static preexisting mutex.  ^Nine static mutexes are
6087 ** used by the current version of SQLite.  Future versions of SQLite
6088 ** may add additional static mutexes.  Static mutexes are for internal
6089 ** use by SQLite only.  Applications that use SQLite mutexes should
6090 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
6091 ** SQLITE_MUTEX_RECURSIVE.
6092 **
6093 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
6094 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
6095 ** returns a different mutex on every call.  ^For the static
6096 ** mutex types, the same mutex is returned on every call that has
6097 ** the same type number.
6098 **
6099 ** ^The sqlite3_mutex_free() routine deallocates a previously
6100 ** allocated dynamic mutex.  Attempting to deallocate a static
6101 ** mutex results in undefined behavior.
6102 **
6103 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
6104 ** to enter a mutex.  ^If another thread is already within the mutex,
6105 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
6106 ** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
6107 ** upon successful entry.  ^(Mutexes created using
6108 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
6109 ** In such cases, the
6110 ** mutex must be exited an equal number of times before another thread
6111 ** can enter.)^  If the same thread tries to enter any mutex other
6112 ** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
6113 **
6114 ** ^(Some systems (for example, Windows 95) do not support the operation
6115 ** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
6116 ** will always return SQLITE_BUSY. The SQLite core only ever uses
6117 ** sqlite3_mutex_try() as an optimization so this is acceptable
6118 ** behavior.)^
6119 **
6120 ** ^The sqlite3_mutex_leave() routine exits a mutex that was
6121 ** previously entered by the same thread.   The behavior
6122 ** is undefined if the mutex is not currently entered by the
6123 ** calling thread or is not currently allocated.
6124 **
6125 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
6126 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
6127 ** behave as no-ops.
6128 **
6129 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
6130 */
6131 SQLITE_API sqlite3_mutex *SQLITE_STDCALL sqlite3_mutex_alloc(int);
6132 SQLITE_API void SQLITE_STDCALL sqlite3_mutex_free(sqlite3_mutex*);
6133 SQLITE_API void SQLITE_STDCALL sqlite3_mutex_enter(sqlite3_mutex*);
6134 SQLITE_API int SQLITE_STDCALL sqlite3_mutex_try(sqlite3_mutex*);
6135 SQLITE_API void SQLITE_STDCALL sqlite3_mutex_leave(sqlite3_mutex*);
6136 
6137 /*
6138 ** CAPI3REF: Mutex Methods Object
6139 **
6140 ** An instance of this structure defines the low-level routines
6141 ** used to allocate and use mutexes.
6142 **
6143 ** Usually, the default mutex implementations provided by SQLite are
6144 ** sufficient, however the application has the option of substituting a custom
6145 ** implementation for specialized deployments or systems for which SQLite
6146 ** does not provide a suitable implementation. In this case, the application
6147 ** creates and populates an instance of this structure to pass
6148 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
6149 ** Additionally, an instance of this structure can be used as an
6150 ** output variable when querying the system for the current mutex
6151 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
6152 **
6153 ** ^The xMutexInit method defined by this structure is invoked as
6154 ** part of system initialization by the sqlite3_initialize() function.
6155 ** ^The xMutexInit routine is called by SQLite exactly once for each
6156 ** effective call to [sqlite3_initialize()].
6157 **
6158 ** ^The xMutexEnd method defined by this structure is invoked as
6159 ** part of system shutdown by the sqlite3_shutdown() function. The
6160 ** implementation of this method is expected to release all outstanding
6161 ** resources obtained by the mutex methods implementation, especially
6162 ** those obtained by the xMutexInit method.  ^The xMutexEnd()
6163 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
6164 **
6165 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
6166 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
6167 ** xMutexNotheld) implement the following interfaces (respectively):
6168 **
6169 ** <ul>
6170 **   <li>  [sqlite3_mutex_alloc()] </li>
6171 **   <li>  [sqlite3_mutex_free()] </li>
6172 **   <li>  [sqlite3_mutex_enter()] </li>
6173 **   <li>  [sqlite3_mutex_try()] </li>
6174 **   <li>  [sqlite3_mutex_leave()] </li>
6175 **   <li>  [sqlite3_mutex_held()] </li>
6176 **   <li>  [sqlite3_mutex_notheld()] </li>
6177 ** </ul>)^
6178 **
6179 ** The only difference is that the public sqlite3_XXX functions enumerated
6180 ** above silently ignore any invocations that pass a NULL pointer instead
6181 ** of a valid mutex handle. The implementations of the methods defined
6182 ** by this structure are not required to handle this case, the results
6183 ** of passing a NULL pointer instead of a valid mutex handle are undefined
6184 ** (i.e. it is acceptable to provide an implementation that segfaults if
6185 ** it is passed a NULL pointer).
6186 **
6187 ** The xMutexInit() method must be threadsafe.  It must be harmless to
6188 ** invoke xMutexInit() multiple times within the same process and without
6189 ** intervening calls to xMutexEnd().  Second and subsequent calls to
6190 ** xMutexInit() must be no-ops.
6191 **
6192 ** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
6193 ** and its associates).  Similarly, xMutexAlloc() must not use SQLite memory
6194 ** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
6195 ** memory allocation for a fast or recursive mutex.
6196 **
6197 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
6198 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
6199 ** If xMutexInit fails in any way, it is expected to clean up after itself
6200 ** prior to returning.
6201 */
6202 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
6203 struct sqlite3_mutex_methods {
6204   int (*xMutexInit)(void);
6205   int (*xMutexEnd)(void);
6206   sqlite3_mutex *(*xMutexAlloc)(int);
6207   void (*xMutexFree)(sqlite3_mutex *);
6208   void (*xMutexEnter)(sqlite3_mutex *);
6209   int (*xMutexTry)(sqlite3_mutex *);
6210   void (*xMutexLeave)(sqlite3_mutex *);
6211   int (*xMutexHeld)(sqlite3_mutex *);
6212   int (*xMutexNotheld)(sqlite3_mutex *);
6213 };
6214 
6215 /*
6216 ** CAPI3REF: Mutex Verification Routines
6217 **
6218 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
6219 ** are intended for use inside assert() statements.  The SQLite core
6220 ** never uses these routines except inside an assert() and applications
6221 ** are advised to follow the lead of the core.  The SQLite core only
6222 ** provides implementations for these routines when it is compiled
6223 ** with the SQLITE_DEBUG flag.  External mutex implementations
6224 ** are only required to provide these routines if SQLITE_DEBUG is
6225 ** defined and if NDEBUG is not defined.
6226 **
6227 ** These routines should return true if the mutex in their argument
6228 ** is held or not held, respectively, by the calling thread.
6229 **
6230 ** The implementation is not required to provide versions of these
6231 ** routines that actually work. If the implementation does not provide working
6232 ** versions of these routines, it should at least provide stubs that always
6233 ** return true so that one does not get spurious assertion failures.
6234 **
6235 ** If the argument to sqlite3_mutex_held() is a NULL pointer then
6236 ** the routine should return 1.   This seems counter-intuitive since
6237 ** clearly the mutex cannot be held if it does not exist.  But
6238 ** the reason the mutex does not exist is because the build is not
6239 ** using mutexes.  And we do not want the assert() containing the
6240 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
6241 ** the appropriate thing to do.  The sqlite3_mutex_notheld()
6242 ** interface should also return 1 when given a NULL pointer.
6243 */
6244 #ifndef NDEBUG
6245 SQLITE_API int SQLITE_STDCALL sqlite3_mutex_held(sqlite3_mutex*);
6246 SQLITE_API int SQLITE_STDCALL sqlite3_mutex_notheld(sqlite3_mutex*);
6247 #endif
6248 
6249 /*
6250 ** CAPI3REF: Mutex Types
6251 **
6252 ** The [sqlite3_mutex_alloc()] interface takes a single argument
6253 ** which is one of these integer constants.
6254 **
6255 ** The set of static mutexes may change from one SQLite release to the
6256 ** next.  Applications that override the built-in mutex logic must be
6257 ** prepared to accommodate additional static mutexes.
6258 */
6259 #define SQLITE_MUTEX_FAST             0
6260 #define SQLITE_MUTEX_RECURSIVE        1
6261 #define SQLITE_MUTEX_STATIC_MASTER    2
6262 #define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
6263 #define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
6264 #define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
6265 #define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_random() */
6266 #define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
6267 #define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
6268 #define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
6269 #define SQLITE_MUTEX_STATIC_APP1      8  /* For use by application */
6270 #define SQLITE_MUTEX_STATIC_APP2      9  /* For use by application */
6271 #define SQLITE_MUTEX_STATIC_APP3     10  /* For use by application */
6272 
6273 /*
6274 ** CAPI3REF: Retrieve the mutex for a database connection
6275 ** METHOD: sqlite3
6276 **
6277 ** ^This interface returns a pointer the [sqlite3_mutex] object that
6278 ** serializes access to the [database connection] given in the argument
6279 ** when the [threading mode] is Serialized.
6280 ** ^If the [threading mode] is Single-thread or Multi-thread then this
6281 ** routine returns a NULL pointer.
6282 */
6283 SQLITE_API sqlite3_mutex *SQLITE_STDCALL sqlite3_db_mutex(sqlite3*);
6284 
6285 /*
6286 ** CAPI3REF: Low-Level Control Of Database Files
6287 ** METHOD: sqlite3
6288 **
6289 ** ^The [sqlite3_file_control()] interface makes a direct call to the
6290 ** xFileControl method for the [sqlite3_io_methods] object associated
6291 ** with a particular database identified by the second argument. ^The
6292 ** name of the database is "main" for the main database or "temp" for the
6293 ** TEMP database, or the name that appears after the AS keyword for
6294 ** databases that are added using the [ATTACH] SQL command.
6295 ** ^A NULL pointer can be used in place of "main" to refer to the
6296 ** main database file.
6297 ** ^The third and fourth parameters to this routine
6298 ** are passed directly through to the second and third parameters of
6299 ** the xFileControl method.  ^The return value of the xFileControl
6300 ** method becomes the return value of this routine.
6301 **
6302 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes
6303 ** a pointer to the underlying [sqlite3_file] object to be written into
6304 ** the space pointed to by the 4th parameter.  ^The SQLITE_FCNTL_FILE_POINTER
6305 ** case is a short-circuit path which does not actually invoke the
6306 ** underlying sqlite3_io_methods.xFileControl method.
6307 **
6308 ** ^If the second parameter (zDbName) does not match the name of any
6309 ** open database file, then SQLITE_ERROR is returned.  ^This error
6310 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
6311 ** or [sqlite3_errmsg()].  The underlying xFileControl method might
6312 ** also return SQLITE_ERROR.  There is no way to distinguish between
6313 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
6314 ** xFileControl method.
6315 **
6316 ** See also: [SQLITE_FCNTL_LOCKSTATE]
6317 */
6318 SQLITE_API int SQLITE_STDCALL sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
6319 
6320 /*
6321 ** CAPI3REF: Testing Interface
6322 **
6323 ** ^The sqlite3_test_control() interface is used to read out internal
6324 ** state of SQLite and to inject faults into SQLite for testing
6325 ** purposes.  ^The first parameter is an operation code that determines
6326 ** the number, meaning, and operation of all subsequent parameters.
6327 **
6328 ** This interface is not for use by applications.  It exists solely
6329 ** for verifying the correct operation of the SQLite library.  Depending
6330 ** on how the SQLite library is compiled, this interface might not exist.
6331 **
6332 ** The details of the operation codes, their meanings, the parameters
6333 ** they take, and what they do are all subject to change without notice.
6334 ** Unlike most of the SQLite API, this function is not guaranteed to
6335 ** operate consistently from one release to the next.
6336 */
6337 SQLITE_API int SQLITE_CDECL sqlite3_test_control(int op, ...);
6338 
6339 /*
6340 ** CAPI3REF: Testing Interface Operation Codes
6341 **
6342 ** These constants are the valid operation code parameters used
6343 ** as the first argument to [sqlite3_test_control()].
6344 **
6345 ** These parameters and their meanings are subject to change
6346 ** without notice.  These values are for testing purposes only.
6347 ** Applications should not use any of these parameters or the
6348 ** [sqlite3_test_control()] interface.
6349 */
6350 #define SQLITE_TESTCTRL_FIRST                    5
6351 #define SQLITE_TESTCTRL_PRNG_SAVE                5
6352 #define SQLITE_TESTCTRL_PRNG_RESTORE             6
6353 #define SQLITE_TESTCTRL_PRNG_RESET               7
6354 #define SQLITE_TESTCTRL_BITVEC_TEST              8
6355 #define SQLITE_TESTCTRL_FAULT_INSTALL            9
6356 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
6357 #define SQLITE_TESTCTRL_PENDING_BYTE            11
6358 #define SQLITE_TESTCTRL_ASSERT                  12
6359 #define SQLITE_TESTCTRL_ALWAYS                  13
6360 #define SQLITE_TESTCTRL_RESERVE                 14
6361 #define SQLITE_TESTCTRL_OPTIMIZATIONS           15
6362 #define SQLITE_TESTCTRL_ISKEYWORD               16
6363 #define SQLITE_TESTCTRL_SCRATCHMALLOC           17
6364 #define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
6365 #define SQLITE_TESTCTRL_EXPLAIN_STMT            19  /* NOT USED */
6366 #define SQLITE_TESTCTRL_NEVER_CORRUPT           20
6367 #define SQLITE_TESTCTRL_VDBE_COVERAGE           21
6368 #define SQLITE_TESTCTRL_BYTEORDER               22
6369 #define SQLITE_TESTCTRL_ISINIT                  23
6370 #define SQLITE_TESTCTRL_SORTER_MMAP             24
6371 #define SQLITE_TESTCTRL_IMPOSTER                25
6372 #define SQLITE_TESTCTRL_LAST                    25
6373 
6374 /*
6375 ** CAPI3REF: SQLite Runtime Status
6376 **
6377 ** ^These interfaces are used to retrieve runtime status information
6378 ** about the performance of SQLite, and optionally to reset various
6379 ** highwater marks.  ^The first argument is an integer code for
6380 ** the specific parameter to measure.  ^(Recognized integer codes
6381 ** are of the form [status parameters | SQLITE_STATUS_...].)^
6382 ** ^The current value of the parameter is returned into *pCurrent.
6383 ** ^The highest recorded value is returned in *pHighwater.  ^If the
6384 ** resetFlag is true, then the highest record value is reset after
6385 ** *pHighwater is written.  ^(Some parameters do not record the highest
6386 ** value.  For those parameters
6387 ** nothing is written into *pHighwater and the resetFlag is ignored.)^
6388 ** ^(Other parameters record only the highwater mark and not the current
6389 ** value.  For these latter parameters nothing is written into *pCurrent.)^
6390 **
6391 ** ^The sqlite3_status() and sqlite3_status64() routines return
6392 ** SQLITE_OK on success and a non-zero [error code] on failure.
6393 **
6394 ** If either the current value or the highwater mark is too large to
6395 ** be represented by a 32-bit integer, then the values returned by
6396 ** sqlite3_status() are undefined.
6397 **
6398 ** See also: [sqlite3_db_status()]
6399 */
6400 SQLITE_API int SQLITE_STDCALL sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
6401 SQLITE_API int SQLITE_STDCALL sqlite3_status64(
6402   int op,
6403   sqlite3_int64 *pCurrent,
6404   sqlite3_int64 *pHighwater,
6405   int resetFlag
6406 );
6407 
6408 
6409 /*
6410 ** CAPI3REF: Status Parameters
6411 ** KEYWORDS: {status parameters}
6412 **
6413 ** These integer constants designate various run-time status parameters
6414 ** that can be returned by [sqlite3_status()].
6415 **
6416 ** <dl>
6417 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
6418 ** <dd>This parameter is the current amount of memory checked out
6419 ** using [sqlite3_malloc()], either directly or indirectly.  The
6420 ** figure includes calls made to [sqlite3_malloc()] by the application
6421 ** and internal memory usage by the SQLite library.  Scratch memory
6422 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache
6423 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
6424 ** this parameter.  The amount returned is the sum of the allocation
6425 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
6426 **
6427 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
6428 ** <dd>This parameter records the largest memory allocation request
6429 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
6430 ** internal equivalents).  Only the value returned in the
6431 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6432 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6433 **
6434 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
6435 ** <dd>This parameter records the number of separate memory allocations
6436 ** currently checked out.</dd>)^
6437 **
6438 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
6439 ** <dd>This parameter returns the number of pages used out of the
6440 ** [pagecache memory allocator] that was configured using
6441 ** [SQLITE_CONFIG_PAGECACHE].  The
6442 ** value returned is in pages, not in bytes.</dd>)^
6443 **
6444 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
6445 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
6446 ** <dd>This parameter returns the number of bytes of page cache
6447 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
6448 ** buffer and where forced to overflow to [sqlite3_malloc()].  The
6449 ** returned value includes allocations that overflowed because they
6450 ** where too large (they were larger than the "sz" parameter to
6451 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
6452 ** no space was left in the page cache.</dd>)^
6453 **
6454 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
6455 ** <dd>This parameter records the largest memory allocation request
6456 ** handed to [pagecache memory allocator].  Only the value returned in the
6457 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6458 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6459 **
6460 ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt>
6461 ** <dd>This parameter returns the number of allocations used out of the
6462 ** [scratch memory allocator] configured using
6463 ** [SQLITE_CONFIG_SCRATCH].  The value returned is in allocations, not
6464 ** in bytes.  Since a single thread may only have one scratch allocation
6465 ** outstanding at time, this parameter also reports the number of threads
6466 ** using scratch memory at the same time.</dd>)^
6467 **
6468 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
6469 ** <dd>This parameter returns the number of bytes of scratch memory
6470 ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH]
6471 ** buffer and where forced to overflow to [sqlite3_malloc()].  The values
6472 ** returned include overflows because the requested allocation was too
6473 ** larger (that is, because the requested allocation was larger than the
6474 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer
6475 ** slots were available.
6476 ** </dd>)^
6477 **
6478 ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
6479 ** <dd>This parameter records the largest memory allocation request
6480 ** handed to [scratch memory allocator].  Only the value returned in the
6481 ** *pHighwater parameter to [sqlite3_status()] is of interest.
6482 ** The value written into the *pCurrent parameter is undefined.</dd>)^
6483 **
6484 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
6485 ** <dd>This parameter records the deepest parser stack.  It is only
6486 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
6487 ** </dl>
6488 **
6489 ** New status parameters may be added from time to time.
6490 */
6491 #define SQLITE_STATUS_MEMORY_USED          0
6492 #define SQLITE_STATUS_PAGECACHE_USED       1
6493 #define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
6494 #define SQLITE_STATUS_SCRATCH_USED         3
6495 #define SQLITE_STATUS_SCRATCH_OVERFLOW     4
6496 #define SQLITE_STATUS_MALLOC_SIZE          5
6497 #define SQLITE_STATUS_PARSER_STACK         6
6498 #define SQLITE_STATUS_PAGECACHE_SIZE       7
6499 #define SQLITE_STATUS_SCRATCH_SIZE         8
6500 #define SQLITE_STATUS_MALLOC_COUNT         9
6501 
6502 /*
6503 ** CAPI3REF: Database Connection Status
6504 ** METHOD: sqlite3
6505 **
6506 ** ^This interface is used to retrieve runtime status information
6507 ** about a single [database connection].  ^The first argument is the
6508 ** database connection object to be interrogated.  ^The second argument
6509 ** is an integer constant, taken from the set of
6510 ** [SQLITE_DBSTATUS options], that
6511 ** determines the parameter to interrogate.  The set of
6512 ** [SQLITE_DBSTATUS options] is likely
6513 ** to grow in future releases of SQLite.
6514 **
6515 ** ^The current value of the requested parameter is written into *pCur
6516 ** and the highest instantaneous value is written into *pHiwtr.  ^If
6517 ** the resetFlg is true, then the highest instantaneous value is
6518 ** reset back down to the current value.
6519 **
6520 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
6521 ** non-zero [error code] on failure.
6522 **
6523 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
6524 */
6525 SQLITE_API int SQLITE_STDCALL sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
6526 
6527 /*
6528 ** CAPI3REF: Status Parameters for database connections
6529 ** KEYWORDS: {SQLITE_DBSTATUS options}
6530 **
6531 ** These constants are the available integer "verbs" that can be passed as
6532 ** the second argument to the [sqlite3_db_status()] interface.
6533 **
6534 ** New verbs may be added in future releases of SQLite. Existing verbs
6535 ** might be discontinued. Applications should check the return code from
6536 ** [sqlite3_db_status()] to make sure that the call worked.
6537 ** The [sqlite3_db_status()] interface will return a non-zero error code
6538 ** if a discontinued or unsupported verb is invoked.
6539 **
6540 ** <dl>
6541 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
6542 ** <dd>This parameter returns the number of lookaside memory slots currently
6543 ** checked out.</dd>)^
6544 **
6545 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
6546 ** <dd>This parameter returns the number malloc attempts that were
6547 ** satisfied using lookaside memory. Only the high-water value is meaningful;
6548 ** the current value is always zero.)^
6549 **
6550 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
6551 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
6552 ** <dd>This parameter returns the number malloc attempts that might have
6553 ** been satisfied using lookaside memory but failed due to the amount of
6554 ** memory requested being larger than the lookaside slot size.
6555 ** Only the high-water value is meaningful;
6556 ** the current value is always zero.)^
6557 **
6558 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
6559 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
6560 ** <dd>This parameter returns the number malloc attempts that might have
6561 ** been satisfied using lookaside memory but failed due to all lookaside
6562 ** memory already being in use.
6563 ** Only the high-water value is meaningful;
6564 ** the current value is always zero.)^
6565 **
6566 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
6567 ** <dd>This parameter returns the approximate number of bytes of heap
6568 ** memory used by all pager caches associated with the database connection.)^
6569 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
6570 **
6571 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
6572 ** <dd>This parameter returns the approximate number of bytes of heap
6573 ** memory used to store the schema for all databases associated
6574 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^
6575 ** ^The full amount of memory used by the schemas is reported, even if the
6576 ** schema memory is shared with other database connections due to
6577 ** [shared cache mode] being enabled.
6578 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
6579 **
6580 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
6581 ** <dd>This parameter returns the approximate number of bytes of heap
6582 ** and lookaside memory used by all prepared statements associated with
6583 ** the database connection.)^
6584 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
6585 ** </dd>
6586 **
6587 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
6588 ** <dd>This parameter returns the number of pager cache hits that have
6589 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
6590 ** is always 0.
6591 ** </dd>
6592 **
6593 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
6594 ** <dd>This parameter returns the number of pager cache misses that have
6595 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
6596 ** is always 0.
6597 ** </dd>
6598 **
6599 ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
6600 ** <dd>This parameter returns the number of dirty cache entries that have
6601 ** been written to disk. Specifically, the number of pages written to the
6602 ** wal file in wal mode databases, or the number of pages written to the
6603 ** database file in rollback mode databases. Any pages written as part of
6604 ** transaction rollback or database recovery operations are not included.
6605 ** If an IO or other error occurs while writing a page to disk, the effect
6606 ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
6607 ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
6608 ** </dd>
6609 **
6610 ** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
6611 ** <dd>This parameter returns zero for the current value if and only if
6612 ** all foreign key constraints (deferred or immediate) have been
6613 ** resolved.)^  ^The highwater mark is always 0.
6614 ** </dd>
6615 ** </dl>
6616 */
6617 #define SQLITE_DBSTATUS_LOOKASIDE_USED       0
6618 #define SQLITE_DBSTATUS_CACHE_USED           1
6619 #define SQLITE_DBSTATUS_SCHEMA_USED          2
6620 #define SQLITE_DBSTATUS_STMT_USED            3
6621 #define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
6622 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
6623 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
6624 #define SQLITE_DBSTATUS_CACHE_HIT            7
6625 #define SQLITE_DBSTATUS_CACHE_MISS           8
6626 #define SQLITE_DBSTATUS_CACHE_WRITE          9
6627 #define SQLITE_DBSTATUS_DEFERRED_FKS        10
6628 #define SQLITE_DBSTATUS_MAX                 10   /* Largest defined DBSTATUS */
6629 
6630 
6631 /*
6632 ** CAPI3REF: Prepared Statement Status
6633 ** METHOD: sqlite3_stmt
6634 **
6635 ** ^(Each prepared statement maintains various
6636 ** [SQLITE_STMTSTATUS counters] that measure the number
6637 ** of times it has performed specific operations.)^  These counters can
6638 ** be used to monitor the performance characteristics of the prepared
6639 ** statements.  For example, if the number of table steps greatly exceeds
6640 ** the number of table searches or result rows, that would tend to indicate
6641 ** that the prepared statement is using a full table scan rather than
6642 ** an index.
6643 **
6644 ** ^(This interface is used to retrieve and reset counter values from
6645 ** a [prepared statement].  The first argument is the prepared statement
6646 ** object to be interrogated.  The second argument
6647 ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
6648 ** to be interrogated.)^
6649 ** ^The current value of the requested counter is returned.
6650 ** ^If the resetFlg is true, then the counter is reset to zero after this
6651 ** interface call returns.
6652 **
6653 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
6654 */
6655 SQLITE_API int SQLITE_STDCALL sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
6656 
6657 /*
6658 ** CAPI3REF: Status Parameters for prepared statements
6659 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
6660 **
6661 ** These preprocessor macros define integer codes that name counter
6662 ** values associated with the [sqlite3_stmt_status()] interface.
6663 ** The meanings of the various counters are as follows:
6664 **
6665 ** <dl>
6666 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
6667 ** <dd>^This is the number of times that SQLite has stepped forward in
6668 ** a table as part of a full table scan.  Large numbers for this counter
6669 ** may indicate opportunities for performance improvement through
6670 ** careful use of indices.</dd>
6671 **
6672 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
6673 ** <dd>^This is the number of sort operations that have occurred.
6674 ** A non-zero value in this counter may indicate an opportunity to
6675 ** improvement performance through careful use of indices.</dd>
6676 **
6677 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
6678 ** <dd>^This is the number of rows inserted into transient indices that
6679 ** were created automatically in order to help joins run faster.
6680 ** A non-zero value in this counter may indicate an opportunity to
6681 ** improvement performance by adding permanent indices that do not
6682 ** need to be reinitialized each time the statement is run.</dd>
6683 **
6684 ** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
6685 ** <dd>^This is the number of virtual machine operations executed
6686 ** by the prepared statement if that number is less than or equal
6687 ** to 2147483647.  The number of virtual machine operations can be
6688 ** used as a proxy for the total work done by the prepared statement.
6689 ** If the number of virtual machine operations exceeds 2147483647
6690 ** then the value returned by this statement status code is undefined.
6691 ** </dd>
6692 ** </dl>
6693 */
6694 #define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
6695 #define SQLITE_STMTSTATUS_SORT              2
6696 #define SQLITE_STMTSTATUS_AUTOINDEX         3
6697 #define SQLITE_STMTSTATUS_VM_STEP           4
6698 
6699 /*
6700 ** CAPI3REF: Custom Page Cache Object
6701 **
6702 ** The sqlite3_pcache type is opaque.  It is implemented by
6703 ** the pluggable module.  The SQLite core has no knowledge of
6704 ** its size or internal structure and never deals with the
6705 ** sqlite3_pcache object except by holding and passing pointers
6706 ** to the object.
6707 **
6708 ** See [sqlite3_pcache_methods2] for additional information.
6709 */
6710 typedef struct sqlite3_pcache sqlite3_pcache;
6711 
6712 /*
6713 ** CAPI3REF: Custom Page Cache Object
6714 **
6715 ** The sqlite3_pcache_page object represents a single page in the
6716 ** page cache.  The page cache will allocate instances of this
6717 ** object.  Various methods of the page cache use pointers to instances
6718 ** of this object as parameters or as their return value.
6719 **
6720 ** See [sqlite3_pcache_methods2] for additional information.
6721 */
6722 typedef struct sqlite3_pcache_page sqlite3_pcache_page;
6723 struct sqlite3_pcache_page {
6724   void *pBuf;        /* The content of the page */
6725   void *pExtra;      /* Extra information associated with the page */
6726 };
6727 
6728 /*
6729 ** CAPI3REF: Application Defined Page Cache.
6730 ** KEYWORDS: {page cache}
6731 **
6732 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
6733 ** register an alternative page cache implementation by passing in an
6734 ** instance of the sqlite3_pcache_methods2 structure.)^
6735 ** In many applications, most of the heap memory allocated by
6736 ** SQLite is used for the page cache.
6737 ** By implementing a
6738 ** custom page cache using this API, an application can better control
6739 ** the amount of memory consumed by SQLite, the way in which
6740 ** that memory is allocated and released, and the policies used to
6741 ** determine exactly which parts of a database file are cached and for
6742 ** how long.
6743 **
6744 ** The alternative page cache mechanism is an
6745 ** extreme measure that is only needed by the most demanding applications.
6746 ** The built-in page cache is recommended for most uses.
6747 **
6748 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
6749 ** internal buffer by SQLite within the call to [sqlite3_config].  Hence
6750 ** the application may discard the parameter after the call to
6751 ** [sqlite3_config()] returns.)^
6752 **
6753 ** [[the xInit() page cache method]]
6754 ** ^(The xInit() method is called once for each effective
6755 ** call to [sqlite3_initialize()])^
6756 ** (usually only once during the lifetime of the process). ^(The xInit()
6757 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
6758 ** The intent of the xInit() method is to set up global data structures
6759 ** required by the custom page cache implementation.
6760 ** ^(If the xInit() method is NULL, then the
6761 ** built-in default page cache is used instead of the application defined
6762 ** page cache.)^
6763 **
6764 ** [[the xShutdown() page cache method]]
6765 ** ^The xShutdown() method is called by [sqlite3_shutdown()].
6766 ** It can be used to clean up
6767 ** any outstanding resources before process shutdown, if required.
6768 ** ^The xShutdown() method may be NULL.
6769 **
6770 ** ^SQLite automatically serializes calls to the xInit method,
6771 ** so the xInit method need not be threadsafe.  ^The
6772 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
6773 ** not need to be threadsafe either.  All other methods must be threadsafe
6774 ** in multithreaded applications.
6775 **
6776 ** ^SQLite will never invoke xInit() more than once without an intervening
6777 ** call to xShutdown().
6778 **
6779 ** [[the xCreate() page cache methods]]
6780 ** ^SQLite invokes the xCreate() method to construct a new cache instance.
6781 ** SQLite will typically create one cache instance for each open database file,
6782 ** though this is not guaranteed. ^The
6783 ** first parameter, szPage, is the size in bytes of the pages that must
6784 ** be allocated by the cache.  ^szPage will always a power of two.  ^The
6785 ** second parameter szExtra is a number of bytes of extra storage
6786 ** associated with each page cache entry.  ^The szExtra parameter will
6787 ** a number less than 250.  SQLite will use the
6788 ** extra szExtra bytes on each page to store metadata about the underlying
6789 ** database page on disk.  The value passed into szExtra depends
6790 ** on the SQLite version, the target platform, and how SQLite was compiled.
6791 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being
6792 ** created will be used to cache database pages of a file stored on disk, or
6793 ** false if it is used for an in-memory database. The cache implementation
6794 ** does not have to do anything special based with the value of bPurgeable;
6795 ** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
6796 ** never invoke xUnpin() except to deliberately delete a page.
6797 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
6798 ** false will always have the "discard" flag set to true.
6799 ** ^Hence, a cache created with bPurgeable false will
6800 ** never contain any unpinned pages.
6801 **
6802 ** [[the xCachesize() page cache method]]
6803 ** ^(The xCachesize() method may be called at any time by SQLite to set the
6804 ** suggested maximum cache-size (number of pages stored by) the cache
6805 ** instance passed as the first argument. This is the value configured using
6806 ** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
6807 ** parameter, the implementation is not required to do anything with this
6808 ** value; it is advisory only.
6809 **
6810 ** [[the xPagecount() page cache methods]]
6811 ** The xPagecount() method must return the number of pages currently
6812 ** stored in the cache, both pinned and unpinned.
6813 **
6814 ** [[the xFetch() page cache methods]]
6815 ** The xFetch() method locates a page in the cache and returns a pointer to
6816 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
6817 ** The pBuf element of the returned sqlite3_pcache_page object will be a
6818 ** pointer to a buffer of szPage bytes used to store the content of a
6819 ** single database page.  The pExtra element of sqlite3_pcache_page will be
6820 ** a pointer to the szExtra bytes of extra storage that SQLite has requested
6821 ** for each entry in the page cache.
6822 **
6823 ** The page to be fetched is determined by the key. ^The minimum key value
6824 ** is 1.  After it has been retrieved using xFetch, the page is considered
6825 ** to be "pinned".
6826 **
6827 ** If the requested page is already in the page cache, then the page cache
6828 ** implementation must return a pointer to the page buffer with its content
6829 ** intact.  If the requested page is not already in the cache, then the
6830 ** cache implementation should use the value of the createFlag
6831 ** parameter to help it determined what action to take:
6832 **
6833 ** <table border=1 width=85% align=center>
6834 ** <tr><th> createFlag <th> Behavior when page is not already in cache
6835 ** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
6836 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
6837 **                 Otherwise return NULL.
6838 ** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
6839 **                 NULL if allocating a new page is effectively impossible.
6840 ** </table>
6841 **
6842 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
6843 ** will only use a createFlag of 2 after a prior call with a createFlag of 1
6844 ** failed.)^  In between the to xFetch() calls, SQLite may
6845 ** attempt to unpin one or more cache pages by spilling the content of
6846 ** pinned pages to disk and synching the operating system disk cache.
6847 **
6848 ** [[the xUnpin() page cache method]]
6849 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
6850 ** as its second argument.  If the third parameter, discard, is non-zero,
6851 ** then the page must be evicted from the cache.
6852 ** ^If the discard parameter is
6853 ** zero, then the page may be discarded or retained at the discretion of
6854 ** page cache implementation. ^The page cache implementation
6855 ** may choose to evict unpinned pages at any time.
6856 **
6857 ** The cache must not perform any reference counting. A single
6858 ** call to xUnpin() unpins the page regardless of the number of prior calls
6859 ** to xFetch().
6860 **
6861 ** [[the xRekey() page cache methods]]
6862 ** The xRekey() method is used to change the key value associated with the
6863 ** page passed as the second argument. If the cache
6864 ** previously contains an entry associated with newKey, it must be
6865 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
6866 ** to be pinned.
6867 **
6868 ** When SQLite calls the xTruncate() method, the cache must discard all
6869 ** existing cache entries with page numbers (keys) greater than or equal
6870 ** to the value of the iLimit parameter passed to xTruncate(). If any
6871 ** of these pages are pinned, they are implicitly unpinned, meaning that
6872 ** they can be safely discarded.
6873 **
6874 ** [[the xDestroy() page cache method]]
6875 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
6876 ** All resources associated with the specified cache should be freed. ^After
6877 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
6878 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2
6879 ** functions.
6880 **
6881 ** [[the xShrink() page cache method]]
6882 ** ^SQLite invokes the xShrink() method when it wants the page cache to
6883 ** free up as much of heap memory as possible.  The page cache implementation
6884 ** is not obligated to free any memory, but well-behaved implementations should
6885 ** do their best.
6886 */
6887 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
6888 struct sqlite3_pcache_methods2 {
6889   int iVersion;
6890   void *pArg;
6891   int (*xInit)(void*);
6892   void (*xShutdown)(void*);
6893   sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
6894   void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6895   int (*xPagecount)(sqlite3_pcache*);
6896   sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6897   void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
6898   void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
6899       unsigned oldKey, unsigned newKey);
6900   void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6901   void (*xDestroy)(sqlite3_pcache*);
6902   void (*xShrink)(sqlite3_pcache*);
6903 };
6904 
6905 /*
6906 ** This is the obsolete pcache_methods object that has now been replaced
6907 ** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
6908 ** retained in the header file for backwards compatibility only.
6909 */
6910 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
6911 struct sqlite3_pcache_methods {
6912   void *pArg;
6913   int (*xInit)(void*);
6914   void (*xShutdown)(void*);
6915   sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
6916   void (*xCachesize)(sqlite3_pcache*, int nCachesize);
6917   int (*xPagecount)(sqlite3_pcache*);
6918   void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
6919   void (*xUnpin)(sqlite3_pcache*, void*, int discard);
6920   void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
6921   void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
6922   void (*xDestroy)(sqlite3_pcache*);
6923 };
6924 
6925 
6926 /*
6927 ** CAPI3REF: Online Backup Object
6928 **
6929 ** The sqlite3_backup object records state information about an ongoing
6930 ** online backup operation.  ^The sqlite3_backup object is created by
6931 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
6932 ** [sqlite3_backup_finish()].
6933 **
6934 ** See Also: [Using the SQLite Online Backup API]
6935 */
6936 typedef struct sqlite3_backup sqlite3_backup;
6937 
6938 /*
6939 ** CAPI3REF: Online Backup API.
6940 **
6941 ** The backup API copies the content of one database into another.
6942 ** It is useful either for creating backups of databases or
6943 ** for copying in-memory databases to or from persistent files.
6944 **
6945 ** See Also: [Using the SQLite Online Backup API]
6946 **
6947 ** ^SQLite holds a write transaction open on the destination database file
6948 ** for the duration of the backup operation.
6949 ** ^The source database is read-locked only while it is being read;
6950 ** it is not locked continuously for the entire backup operation.
6951 ** ^Thus, the backup may be performed on a live source database without
6952 ** preventing other database connections from
6953 ** reading or writing to the source database while the backup is underway.
6954 **
6955 ** ^(To perform a backup operation:
6956 **   <ol>
6957 **     <li><b>sqlite3_backup_init()</b> is called once to initialize the
6958 **         backup,
6959 **     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
6960 **         the data between the two databases, and finally
6961 **     <li><b>sqlite3_backup_finish()</b> is called to release all resources
6962 **         associated with the backup operation.
6963 **   </ol>)^
6964 ** There should be exactly one call to sqlite3_backup_finish() for each
6965 ** successful call to sqlite3_backup_init().
6966 **
6967 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
6968 **
6969 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
6970 ** [database connection] associated with the destination database
6971 ** and the database name, respectively.
6972 ** ^The database name is "main" for the main database, "temp" for the
6973 ** temporary database, or the name specified after the AS keyword in
6974 ** an [ATTACH] statement for an attached database.
6975 ** ^The S and M arguments passed to
6976 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
6977 ** and database name of the source database, respectively.
6978 ** ^The source and destination [database connections] (parameters S and D)
6979 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
6980 ** an error.
6981 **
6982 ** ^A call to sqlite3_backup_init() will fail, returning SQLITE_ERROR, if
6983 ** there is already a read or read-write transaction open on the
6984 ** destination database.
6985 **
6986 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
6987 ** returned and an error code and error message are stored in the
6988 ** destination [database connection] D.
6989 ** ^The error code and message for the failed call to sqlite3_backup_init()
6990 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
6991 ** [sqlite3_errmsg16()] functions.
6992 ** ^A successful call to sqlite3_backup_init() returns a pointer to an
6993 ** [sqlite3_backup] object.
6994 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
6995 ** sqlite3_backup_finish() functions to perform the specified backup
6996 ** operation.
6997 **
6998 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
6999 **
7000 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
7001 ** the source and destination databases specified by [sqlite3_backup] object B.
7002 ** ^If N is negative, all remaining source pages are copied.
7003 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
7004 ** are still more pages to be copied, then the function returns [SQLITE_OK].
7005 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
7006 ** from source to destination, then it returns [SQLITE_DONE].
7007 ** ^If an error occurs while running sqlite3_backup_step(B,N),
7008 ** then an [error code] is returned. ^As well as [SQLITE_OK] and
7009 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
7010 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
7011 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
7012 **
7013 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
7014 ** <ol>
7015 ** <li> the destination database was opened read-only, or
7016 ** <li> the destination database is using write-ahead-log journaling
7017 ** and the destination and source page sizes differ, or
7018 ** <li> the destination database is an in-memory database and the
7019 ** destination and source page sizes differ.
7020 ** </ol>)^
7021 **
7022 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
7023 ** the [sqlite3_busy_handler | busy-handler function]
7024 ** is invoked (if one is specified). ^If the
7025 ** busy-handler returns non-zero before the lock is available, then
7026 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
7027 ** sqlite3_backup_step() can be retried later. ^If the source
7028 ** [database connection]
7029 ** is being used to write to the source database when sqlite3_backup_step()
7030 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
7031 ** case the call to sqlite3_backup_step() can be retried later on. ^(If
7032 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
7033 ** [SQLITE_READONLY] is returned, then
7034 ** there is no point in retrying the call to sqlite3_backup_step(). These
7035 ** errors are considered fatal.)^  The application must accept
7036 ** that the backup operation has failed and pass the backup operation handle
7037 ** to the sqlite3_backup_finish() to release associated resources.
7038 **
7039 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
7040 ** on the destination file. ^The exclusive lock is not released until either
7041 ** sqlite3_backup_finish() is called or the backup operation is complete
7042 ** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
7043 ** sqlite3_backup_step() obtains a [shared lock] on the source database that
7044 ** lasts for the duration of the sqlite3_backup_step() call.
7045 ** ^Because the source database is not locked between calls to
7046 ** sqlite3_backup_step(), the source database may be modified mid-way
7047 ** through the backup process.  ^If the source database is modified by an
7048 ** external process or via a database connection other than the one being
7049 ** used by the backup operation, then the backup will be automatically
7050 ** restarted by the next call to sqlite3_backup_step(). ^If the source
7051 ** database is modified by the using the same database connection as is used
7052 ** by the backup operation, then the backup database is automatically
7053 ** updated at the same time.
7054 **
7055 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
7056 **
7057 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
7058 ** application wishes to abandon the backup operation, the application
7059 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
7060 ** ^The sqlite3_backup_finish() interfaces releases all
7061 ** resources associated with the [sqlite3_backup] object.
7062 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
7063 ** active write-transaction on the destination database is rolled back.
7064 ** The [sqlite3_backup] object is invalid
7065 ** and may not be used following a call to sqlite3_backup_finish().
7066 **
7067 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
7068 ** sqlite3_backup_step() errors occurred, regardless or whether or not
7069 ** sqlite3_backup_step() completed.
7070 ** ^If an out-of-memory condition or IO error occurred during any prior
7071 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
7072 ** sqlite3_backup_finish() returns the corresponding [error code].
7073 **
7074 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
7075 ** is not a permanent error and does not affect the return value of
7076 ** sqlite3_backup_finish().
7077 **
7078 ** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
7079 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
7080 **
7081 ** ^The sqlite3_backup_remaining() routine returns the number of pages still
7082 ** to be backed up at the conclusion of the most recent sqlite3_backup_step().
7083 ** ^The sqlite3_backup_pagecount() routine returns the total number of pages
7084 ** in the source database at the conclusion of the most recent
7085 ** sqlite3_backup_step().
7086 ** ^(The values returned by these functions are only updated by
7087 ** sqlite3_backup_step(). If the source database is modified in a way that
7088 ** changes the size of the source database or the number of pages remaining,
7089 ** those changes are not reflected in the output of sqlite3_backup_pagecount()
7090 ** and sqlite3_backup_remaining() until after the next
7091 ** sqlite3_backup_step().)^
7092 **
7093 ** <b>Concurrent Usage of Database Handles</b>
7094 **
7095 ** ^The source [database connection] may be used by the application for other
7096 ** purposes while a backup operation is underway or being initialized.
7097 ** ^If SQLite is compiled and configured to support threadsafe database
7098 ** connections, then the source database connection may be used concurrently
7099 ** from within other threads.
7100 **
7101 ** However, the application must guarantee that the destination
7102 ** [database connection] is not passed to any other API (by any thread) after
7103 ** sqlite3_backup_init() is called and before the corresponding call to
7104 ** sqlite3_backup_finish().  SQLite does not currently check to see
7105 ** if the application incorrectly accesses the destination [database connection]
7106 ** and so no error code is reported, but the operations may malfunction
7107 ** nevertheless.  Use of the destination database connection while a
7108 ** backup is in progress might also also cause a mutex deadlock.
7109 **
7110 ** If running in [shared cache mode], the application must
7111 ** guarantee that the shared cache used by the destination database
7112 ** is not accessed while the backup is running. In practice this means
7113 ** that the application must guarantee that the disk file being
7114 ** backed up to is not accessed by any connection within the process,
7115 ** not just the specific connection that was passed to sqlite3_backup_init().
7116 **
7117 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple
7118 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
7119 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
7120 ** APIs are not strictly speaking threadsafe. If they are invoked at the
7121 ** same time as another thread is invoking sqlite3_backup_step() it is
7122 ** possible that they return invalid values.
7123 */
7124 SQLITE_API sqlite3_backup *SQLITE_STDCALL sqlite3_backup_init(
7125   sqlite3 *pDest,                        /* Destination database handle */
7126   const char *zDestName,                 /* Destination database name */
7127   sqlite3 *pSource,                      /* Source database handle */
7128   const char *zSourceName                /* Source database name */
7129 );
7130 SQLITE_API int SQLITE_STDCALL sqlite3_backup_step(sqlite3_backup *p, int nPage);
7131 SQLITE_API int SQLITE_STDCALL sqlite3_backup_finish(sqlite3_backup *p);
7132 SQLITE_API int SQLITE_STDCALL sqlite3_backup_remaining(sqlite3_backup *p);
7133 SQLITE_API int SQLITE_STDCALL sqlite3_backup_pagecount(sqlite3_backup *p);
7134 
7135 /*
7136 ** CAPI3REF: Unlock Notification
7137 ** METHOD: sqlite3
7138 **
7139 ** ^When running in shared-cache mode, a database operation may fail with
7140 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
7141 ** individual tables within the shared-cache cannot be obtained. See
7142 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
7143 ** ^This API may be used to register a callback that SQLite will invoke
7144 ** when the connection currently holding the required lock relinquishes it.
7145 ** ^This API is only available if the library was compiled with the
7146 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
7147 **
7148 ** See Also: [Using the SQLite Unlock Notification Feature].
7149 **
7150 ** ^Shared-cache locks are released when a database connection concludes
7151 ** its current transaction, either by committing it or rolling it back.
7152 **
7153 ** ^When a connection (known as the blocked connection) fails to obtain a
7154 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
7155 ** identity of the database connection (the blocking connection) that
7156 ** has locked the required resource is stored internally. ^After an
7157 ** application receives an SQLITE_LOCKED error, it may call the
7158 ** sqlite3_unlock_notify() method with the blocked connection handle as
7159 ** the first argument to register for a callback that will be invoked
7160 ** when the blocking connections current transaction is concluded. ^The
7161 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
7162 ** call that concludes the blocking connections transaction.
7163 **
7164 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
7165 ** there is a chance that the blocking connection will have already
7166 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
7167 ** If this happens, then the specified callback is invoked immediately,
7168 ** from within the call to sqlite3_unlock_notify().)^
7169 **
7170 ** ^If the blocked connection is attempting to obtain a write-lock on a
7171 ** shared-cache table, and more than one other connection currently holds
7172 ** a read-lock on the same table, then SQLite arbitrarily selects one of
7173 ** the other connections to use as the blocking connection.
7174 **
7175 ** ^(There may be at most one unlock-notify callback registered by a
7176 ** blocked connection. If sqlite3_unlock_notify() is called when the
7177 ** blocked connection already has a registered unlock-notify callback,
7178 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
7179 ** called with a NULL pointer as its second argument, then any existing
7180 ** unlock-notify callback is canceled. ^The blocked connections
7181 ** unlock-notify callback may also be canceled by closing the blocked
7182 ** connection using [sqlite3_close()].
7183 **
7184 ** The unlock-notify callback is not reentrant. If an application invokes
7185 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
7186 ** crash or deadlock may be the result.
7187 **
7188 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
7189 ** returns SQLITE_OK.
7190 **
7191 ** <b>Callback Invocation Details</b>
7192 **
7193 ** When an unlock-notify callback is registered, the application provides a
7194 ** single void* pointer that is passed to the callback when it is invoked.
7195 ** However, the signature of the callback function allows SQLite to pass
7196 ** it an array of void* context pointers. The first argument passed to
7197 ** an unlock-notify callback is a pointer to an array of void* pointers,
7198 ** and the second is the number of entries in the array.
7199 **
7200 ** When a blocking connections transaction is concluded, there may be
7201 ** more than one blocked connection that has registered for an unlock-notify
7202 ** callback. ^If two or more such blocked connections have specified the
7203 ** same callback function, then instead of invoking the callback function
7204 ** multiple times, it is invoked once with the set of void* context pointers
7205 ** specified by the blocked connections bundled together into an array.
7206 ** This gives the application an opportunity to prioritize any actions
7207 ** related to the set of unblocked database connections.
7208 **
7209 ** <b>Deadlock Detection</b>
7210 **
7211 ** Assuming that after registering for an unlock-notify callback a
7212 ** database waits for the callback to be issued before taking any further
7213 ** action (a reasonable assumption), then using this API may cause the
7214 ** application to deadlock. For example, if connection X is waiting for
7215 ** connection Y's transaction to be concluded, and similarly connection
7216 ** Y is waiting on connection X's transaction, then neither connection
7217 ** will proceed and the system may remain deadlocked indefinitely.
7218 **
7219 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
7220 ** detection. ^If a given call to sqlite3_unlock_notify() would put the
7221 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
7222 ** unlock-notify callback is registered. The system is said to be in
7223 ** a deadlocked state if connection A has registered for an unlock-notify
7224 ** callback on the conclusion of connection B's transaction, and connection
7225 ** B has itself registered for an unlock-notify callback when connection
7226 ** A's transaction is concluded. ^Indirect deadlock is also detected, so
7227 ** the system is also considered to be deadlocked if connection B has
7228 ** registered for an unlock-notify callback on the conclusion of connection
7229 ** C's transaction, where connection C is waiting on connection A. ^Any
7230 ** number of levels of indirection are allowed.
7231 **
7232 ** <b>The "DROP TABLE" Exception</b>
7233 **
7234 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
7235 ** always appropriate to call sqlite3_unlock_notify(). There is however,
7236 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
7237 ** SQLite checks if there are any currently executing SELECT statements
7238 ** that belong to the same connection. If there are, SQLITE_LOCKED is
7239 ** returned. In this case there is no "blocking connection", so invoking
7240 ** sqlite3_unlock_notify() results in the unlock-notify callback being
7241 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
7242 ** or "DROP INDEX" query, an infinite loop might be the result.
7243 **
7244 ** One way around this problem is to check the extended error code returned
7245 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
7246 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
7247 ** the special "DROP TABLE/INDEX" case, the extended error code is just
7248 ** SQLITE_LOCKED.)^
7249 */
7250 SQLITE_API int SQLITE_STDCALL sqlite3_unlock_notify(
7251   sqlite3 *pBlocked,                          /* Waiting connection */
7252   void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
7253   void *pNotifyArg                            /* Argument to pass to xNotify */
7254 );
7255 
7256 
7257 /*
7258 ** CAPI3REF: String Comparison
7259 **
7260 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
7261 ** and extensions to compare the contents of two buffers containing UTF-8
7262 ** strings in a case-independent fashion, using the same definition of "case
7263 ** independence" that SQLite uses internally when comparing identifiers.
7264 */
7265 SQLITE_API int SQLITE_STDCALL sqlite3_stricmp(const char *, const char *);
7266 SQLITE_API int SQLITE_STDCALL sqlite3_strnicmp(const char *, const char *, int);
7267 
7268 /*
7269 ** CAPI3REF: String Globbing
7270 *
7271 ** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches
7272 ** the glob pattern P, and it returns non-zero if string X does not match
7273 ** the glob pattern P.  ^The definition of glob pattern matching used in
7274 ** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
7275 ** SQL dialect used by SQLite.  ^The sqlite3_strglob(P,X) function is case
7276 ** sensitive.
7277 **
7278 ** Note that this routine returns zero on a match and non-zero if the strings
7279 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
7280 */
7281 SQLITE_API int SQLITE_STDCALL sqlite3_strglob(const char *zGlob, const char *zStr);
7282 
7283 /*
7284 ** CAPI3REF: Error Logging Interface
7285 **
7286 ** ^The [sqlite3_log()] interface writes a message into the [error log]
7287 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
7288 ** ^If logging is enabled, the zFormat string and subsequent arguments are
7289 ** used with [sqlite3_snprintf()] to generate the final output string.
7290 **
7291 ** The sqlite3_log() interface is intended for use by extensions such as
7292 ** virtual tables, collating functions, and SQL functions.  While there is
7293 ** nothing to prevent an application from calling sqlite3_log(), doing so
7294 ** is considered bad form.
7295 **
7296 ** The zFormat string must not be NULL.
7297 **
7298 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
7299 ** will not use dynamically allocated memory.  The log message is stored in
7300 ** a fixed-length buffer on the stack.  If the log message is longer than
7301 ** a few hundred characters, it will be truncated to the length of the
7302 ** buffer.
7303 */
7304 SQLITE_API void SQLITE_CDECL sqlite3_log(int iErrCode, const char *zFormat, ...);
7305 
7306 /*
7307 ** CAPI3REF: Write-Ahead Log Commit Hook
7308 ** METHOD: sqlite3
7309 **
7310 ** ^The [sqlite3_wal_hook()] function is used to register a callback that
7311 ** is invoked each time data is committed to a database in wal mode.
7312 **
7313 ** ^(The callback is invoked by SQLite after the commit has taken place and
7314 ** the associated write-lock on the database released)^, so the implementation
7315 ** may read, write or [checkpoint] the database as required.
7316 **
7317 ** ^The first parameter passed to the callback function when it is invoked
7318 ** is a copy of the third parameter passed to sqlite3_wal_hook() when
7319 ** registering the callback. ^The second is a copy of the database handle.
7320 ** ^The third parameter is the name of the database that was written to -
7321 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
7322 ** is the number of pages currently in the write-ahead log file,
7323 ** including those that were just committed.
7324 **
7325 ** The callback function should normally return [SQLITE_OK].  ^If an error
7326 ** code is returned, that error will propagate back up through the
7327 ** SQLite code base to cause the statement that provoked the callback
7328 ** to report an error, though the commit will have still occurred. If the
7329 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
7330 ** that does not correspond to any valid SQLite error code, the results
7331 ** are undefined.
7332 **
7333 ** A single database handle may have at most a single write-ahead log callback
7334 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
7335 ** previously registered write-ahead log callback. ^Note that the
7336 ** [sqlite3_wal_autocheckpoint()] interface and the
7337 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
7338 ** those overwrite any prior [sqlite3_wal_hook()] settings.
7339 */
7340 SQLITE_API void *SQLITE_STDCALL sqlite3_wal_hook(
7341   sqlite3*,
7342   int(*)(void *,sqlite3*,const char*,int),
7343   void*
7344 );
7345 
7346 /*
7347 ** CAPI3REF: Configure an auto-checkpoint
7348 ** METHOD: sqlite3
7349 **
7350 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
7351 ** [sqlite3_wal_hook()] that causes any database on [database connection] D
7352 ** to automatically [checkpoint]
7353 ** after committing a transaction if there are N or
7354 ** more frames in the [write-ahead log] file.  ^Passing zero or
7355 ** a negative value as the nFrame parameter disables automatic
7356 ** checkpoints entirely.
7357 **
7358 ** ^The callback registered by this function replaces any existing callback
7359 ** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
7360 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
7361 ** configured by this function.
7362 **
7363 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
7364 ** from SQL.
7365 **
7366 ** ^Checkpoints initiated by this mechanism are
7367 ** [sqlite3_wal_checkpoint_v2|PASSIVE].
7368 **
7369 ** ^Every new [database connection] defaults to having the auto-checkpoint
7370 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
7371 ** pages.  The use of this interface
7372 ** is only necessary if the default setting is found to be suboptimal
7373 ** for a particular application.
7374 */
7375 SQLITE_API int SQLITE_STDCALL sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
7376 
7377 /*
7378 ** CAPI3REF: Checkpoint a database
7379 ** METHOD: sqlite3
7380 **
7381 ** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
7382 ** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
7383 **
7384 ** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
7385 ** [write-ahead log] for database X on [database connection] D to be
7386 ** transferred into the database file and for the write-ahead log to
7387 ** be reset.  See the [checkpointing] documentation for addition
7388 ** information.
7389 **
7390 ** This interface used to be the only way to cause a checkpoint to
7391 ** occur.  But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
7392 ** interface was added.  This interface is retained for backwards
7393 ** compatibility and as a convenience for applications that need to manually
7394 ** start a callback but which do not need the full power (and corresponding
7395 ** complication) of [sqlite3_wal_checkpoint_v2()].
7396 */
7397 SQLITE_API int SQLITE_STDCALL sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
7398 
7399 /*
7400 ** CAPI3REF: Checkpoint a database
7401 ** METHOD: sqlite3
7402 **
7403 ** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
7404 ** operation on database X of [database connection] D in mode M.  Status
7405 ** information is written back into integers pointed to by L and C.)^
7406 ** ^(The M parameter must be a valid [checkpoint mode]:)^
7407 **
7408 ** <dl>
7409 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
7410 **   ^Checkpoint as many frames as possible without waiting for any database
7411 **   readers or writers to finish, then sync the database file if all frames
7412 **   in the log were checkpointed. ^The [busy-handler callback]
7413 **   is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
7414 **   ^On the other hand, passive mode might leave the checkpoint unfinished
7415 **   if there are concurrent readers or writers.
7416 **
7417 ** <dt>SQLITE_CHECKPOINT_FULL<dd>
7418 **   ^This mode blocks (it invokes the
7419 **   [sqlite3_busy_handler|busy-handler callback]) until there is no
7420 **   database writer and all readers are reading from the most recent database
7421 **   snapshot. ^It then checkpoints all frames in the log file and syncs the
7422 **   database file. ^This mode blocks new database writers while it is pending,
7423 **   but new database readers are allowed to continue unimpeded.
7424 **
7425 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
7426 **   ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
7427 **   that after checkpointing the log file it blocks (calls the
7428 **   [busy-handler callback])
7429 **   until all readers are reading from the database file only. ^This ensures
7430 **   that the next writer will restart the log file from the beginning.
7431 **   ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
7432 **   database writer attempts while it is pending, but does not impede readers.
7433 **
7434 ** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
7435 **   ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
7436 **   addition that it also truncates the log file to zero bytes just prior
7437 **   to a successful return.
7438 ** </dl>
7439 **
7440 ** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
7441 ** the log file or to -1 if the checkpoint could not run because
7442 ** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
7443 ** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
7444 ** log file (including any that were already checkpointed before the function
7445 ** was called) or to -1 if the checkpoint could not run due to an error or
7446 ** because the database is not in WAL mode. ^Note that upon successful
7447 ** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
7448 ** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
7449 **
7450 ** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
7451 ** any other process is running a checkpoint operation at the same time, the
7452 ** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
7453 ** busy-handler configured, it will not be invoked in this case.
7454 **
7455 ** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
7456 ** exclusive "writer" lock on the database file. ^If the writer lock cannot be
7457 ** obtained immediately, and a busy-handler is configured, it is invoked and
7458 ** the writer lock retried until either the busy-handler returns 0 or the lock
7459 ** is successfully obtained. ^The busy-handler is also invoked while waiting for
7460 ** database readers as described above. ^If the busy-handler returns 0 before
7461 ** the writer lock is obtained or while waiting for database readers, the
7462 ** checkpoint operation proceeds from that point in the same way as
7463 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
7464 ** without blocking any further. ^SQLITE_BUSY is returned in this case.
7465 **
7466 ** ^If parameter zDb is NULL or points to a zero length string, then the
7467 ** specified operation is attempted on all WAL databases [attached] to
7468 ** [database connection] db.  In this case the
7469 ** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
7470 ** an SQLITE_BUSY error is encountered when processing one or more of the
7471 ** attached WAL databases, the operation is still attempted on any remaining
7472 ** attached databases and SQLITE_BUSY is returned at the end. ^If any other
7473 ** error occurs while processing an attached database, processing is abandoned
7474 ** and the error code is returned to the caller immediately. ^If no error
7475 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached
7476 ** databases, SQLITE_OK is returned.
7477 **
7478 ** ^If database zDb is the name of an attached database that is not in WAL
7479 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
7480 ** zDb is not NULL (or a zero length string) and is not the name of any
7481 ** attached database, SQLITE_ERROR is returned to the caller.
7482 **
7483 ** ^Unless it returns SQLITE_MISUSE,
7484 ** the sqlite3_wal_checkpoint_v2() interface
7485 ** sets the error information that is queried by
7486 ** [sqlite3_errcode()] and [sqlite3_errmsg()].
7487 **
7488 ** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
7489 ** from SQL.
7490 */
7491 SQLITE_API int SQLITE_STDCALL sqlite3_wal_checkpoint_v2(
7492   sqlite3 *db,                    /* Database handle */
7493   const char *zDb,                /* Name of attached database (or NULL) */
7494   int eMode,                      /* SQLITE_CHECKPOINT_* value */
7495   int *pnLog,                     /* OUT: Size of WAL log in frames */
7496   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
7497 );
7498 
7499 /*
7500 ** CAPI3REF: Checkpoint Mode Values
7501 ** KEYWORDS: {checkpoint mode}
7502 **
7503 ** These constants define all valid values for the "checkpoint mode" passed
7504 ** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
7505 ** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
7506 ** meaning of each of these checkpoint modes.
7507 */
7508 #define SQLITE_CHECKPOINT_PASSIVE  0  /* Do as much as possible w/o blocking */
7509 #define SQLITE_CHECKPOINT_FULL     1  /* Wait for writers, then checkpoint */
7510 #define SQLITE_CHECKPOINT_RESTART  2  /* Like FULL but wait for for readers */
7511 #define SQLITE_CHECKPOINT_TRUNCATE 3  /* Like RESTART but also truncate WAL */
7512 
7513 /*
7514 ** CAPI3REF: Virtual Table Interface Configuration
7515 **
7516 ** This function may be called by either the [xConnect] or [xCreate] method
7517 ** of a [virtual table] implementation to configure
7518 ** various facets of the virtual table interface.
7519 **
7520 ** If this interface is invoked outside the context of an xConnect or
7521 ** xCreate virtual table method then the behavior is undefined.
7522 **
7523 ** At present, there is only one option that may be configured using
7524 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].)  Further options
7525 ** may be added in the future.
7526 */
7527 SQLITE_API int SQLITE_CDECL sqlite3_vtab_config(sqlite3*, int op, ...);
7528 
7529 /*
7530 ** CAPI3REF: Virtual Table Configuration Options
7531 **
7532 ** These macros define the various options to the
7533 ** [sqlite3_vtab_config()] interface that [virtual table] implementations
7534 ** can use to customize and optimize their behavior.
7535 **
7536 ** <dl>
7537 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
7538 ** <dd>Calls of the form
7539 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
7540 ** where X is an integer.  If X is zero, then the [virtual table] whose
7541 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
7542 ** support constraints.  In this configuration (which is the default) if
7543 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
7544 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
7545 ** specified as part of the users SQL statement, regardless of the actual
7546 ** ON CONFLICT mode specified.
7547 **
7548 ** If X is non-zero, then the virtual table implementation guarantees
7549 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
7550 ** any modifications to internal or persistent data structures have been made.
7551 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
7552 ** is able to roll back a statement or database transaction, and abandon
7553 ** or continue processing the current SQL statement as appropriate.
7554 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
7555 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
7556 ** had been ABORT.
7557 **
7558 ** Virtual table implementations that are required to handle OR REPLACE
7559 ** must do so within the [xUpdate] method. If a call to the
7560 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON
7561 ** CONFLICT policy is REPLACE, the virtual table implementation should
7562 ** silently replace the appropriate rows within the xUpdate callback and
7563 ** return SQLITE_OK. Or, if this is not possible, it may return
7564 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
7565 ** constraint handling.
7566 ** </dl>
7567 */
7568 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
7569 
7570 /*
7571 ** CAPI3REF: Determine The Virtual Table Conflict Policy
7572 **
7573 ** This function may only be called from within a call to the [xUpdate] method
7574 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
7575 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
7576 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
7577 ** of the SQL statement that triggered the call to the [xUpdate] method of the
7578 ** [virtual table].
7579 */
7580 SQLITE_API int SQLITE_STDCALL sqlite3_vtab_on_conflict(sqlite3 *);
7581 
7582 /*
7583 ** CAPI3REF: Conflict resolution modes
7584 ** KEYWORDS: {conflict resolution mode}
7585 **
7586 ** These constants are returned by [sqlite3_vtab_on_conflict()] to
7587 ** inform a [virtual table] implementation what the [ON CONFLICT] mode
7588 ** is for the SQL statement being evaluated.
7589 **
7590 ** Note that the [SQLITE_IGNORE] constant is also used as a potential
7591 ** return value from the [sqlite3_set_authorizer()] callback and that
7592 ** [SQLITE_ABORT] is also a [result code].
7593 */
7594 #define SQLITE_ROLLBACK 1
7595 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
7596 #define SQLITE_FAIL     3
7597 /* #define SQLITE_ABORT 4  // Also an error code */
7598 #define SQLITE_REPLACE  5
7599 
7600 /*
7601 ** CAPI3REF: Prepared Statement Scan Status Opcodes
7602 ** KEYWORDS: {scanstatus options}
7603 **
7604 ** The following constants can be used for the T parameter to the
7605 ** [sqlite3_stmt_scanstatus(S,X,T,V)] interface.  Each constant designates a
7606 ** different metric for sqlite3_stmt_scanstatus() to return.
7607 **
7608 ** When the value returned to V is a string, space to hold that string is
7609 ** managed by the prepared statement S and will be automatically freed when
7610 ** S is finalized.
7611 **
7612 ** <dl>
7613 ** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
7614 ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be
7615 ** set to the total number of times that the X-th loop has run.</dd>
7616 **
7617 ** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
7618 ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set
7619 ** to the total number of rows examined by all iterations of the X-th loop.</dd>
7620 **
7621 ** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
7622 ** <dd>^The "double" variable pointed to by the T parameter will be set to the
7623 ** query planner's estimate for the average number of rows output from each
7624 ** iteration of the X-th loop.  If the query planner's estimates was accurate,
7625 ** then this value will approximate the quotient NVISIT/NLOOP and the
7626 ** product of this value for all prior loops with the same SELECTID will
7627 ** be the NLOOP value for the current loop.
7628 **
7629 ** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
7630 ** <dd>^The "const char *" variable pointed to by the T parameter will be set
7631 ** to a zero-terminated UTF-8 string containing the name of the index or table
7632 ** used for the X-th loop.
7633 **
7634 ** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
7635 ** <dd>^The "const char *" variable pointed to by the T parameter will be set
7636 ** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
7637 ** description for the X-th loop.
7638 **
7639 ** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt>
7640 ** <dd>^The "int" variable pointed to by the T parameter will be set to the
7641 ** "select-id" for the X-th loop.  The select-id identifies which query or
7642 ** subquery the loop is part of.  The main query has a select-id of zero.
7643 ** The select-id is the same value as is output in the first column
7644 ** of an [EXPLAIN QUERY PLAN] query.
7645 ** </dl>
7646 */
7647 #define SQLITE_SCANSTAT_NLOOP    0
7648 #define SQLITE_SCANSTAT_NVISIT   1
7649 #define SQLITE_SCANSTAT_EST      2
7650 #define SQLITE_SCANSTAT_NAME     3
7651 #define SQLITE_SCANSTAT_EXPLAIN  4
7652 #define SQLITE_SCANSTAT_SELECTID 5
7653 
7654 /*
7655 ** CAPI3REF: Prepared Statement Scan Status
7656 ** METHOD: sqlite3_stmt
7657 **
7658 ** This interface returns information about the predicted and measured
7659 ** performance for pStmt.  Advanced applications can use this
7660 ** interface to compare the predicted and the measured performance and
7661 ** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
7662 **
7663 ** Since this interface is expected to be rarely used, it is only
7664 ** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
7665 ** compile-time option.
7666 **
7667 ** The "iScanStatusOp" parameter determines which status information to return.
7668 ** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
7669 ** of this interface is undefined.
7670 ** ^The requested measurement is written into a variable pointed to by
7671 ** the "pOut" parameter.
7672 ** Parameter "idx" identifies the specific loop to retrieve statistics for.
7673 ** Loops are numbered starting from zero. ^If idx is out of range - less than
7674 ** zero or greater than or equal to the total number of loops used to implement
7675 ** the statement - a non-zero value is returned and the variable that pOut
7676 ** points to is unchanged.
7677 **
7678 ** ^Statistics might not be available for all loops in all statements. ^In cases
7679 ** where there exist loops with no available statistics, this function behaves
7680 ** as if the loop did not exist - it returns non-zero and leave the variable
7681 ** that pOut points to unchanged.
7682 **
7683 ** See also: [sqlite3_stmt_scanstatus_reset()]
7684 */
7685 SQLITE_API SQLITE_EXPERIMENTAL int SQLITE_STDCALL sqlite3_stmt_scanstatus(
7686   sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
7687   int idx,                  /* Index of loop to report on */
7688   int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
7689   void *pOut                /* Result written here */
7690 );
7691 
7692 /*
7693 ** CAPI3REF: Zero Scan-Status Counters
7694 ** METHOD: sqlite3_stmt
7695 **
7696 ** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
7697 **
7698 ** This API is only available if the library is built with pre-processor
7699 ** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
7700 */
7701 SQLITE_API SQLITE_EXPERIMENTAL void SQLITE_STDCALL sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
7702 
7703 
7704 /*
7705 ** Undo the hack that converts floating point types to integer for
7706 ** builds on processors without floating point support.
7707 */
7708 #ifdef SQLITE_OMIT_FLOATING_POINT
7709 # undef double
7710 #endif
7711 
7712 #ifdef __cplusplus
7713 }  /* End of the 'extern "C"' block */
7714 #endif
7715 #endif /* _SQLITE3_H_ */
7716 
7717 /*
7718 ** 2010 August 30
7719 **
7720 ** The author disclaims copyright to this source code.  In place of
7721 ** a legal notice, here is a blessing:
7722 **
7723 **    May you do good and not evil.
7724 **    May you find forgiveness for yourself and forgive others.
7725 **    May you share freely, never taking more than you give.
7726 **
7727 *************************************************************************
7728 */
7729 
7730 #ifndef _SQLITE3RTREE_H_
7731 #define _SQLITE3RTREE_H_
7732 
7733 
7734 #ifdef __cplusplus
7735 extern "C" {
7736 #endif
7737 
7738 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
7739 typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
7740 
7741 /* The double-precision datatype used by RTree depends on the
7742 ** SQLITE_RTREE_INT_ONLY compile-time option.
7743 */
7744 #ifdef SQLITE_RTREE_INT_ONLY
7745   typedef sqlite3_int64 sqlite3_rtree_dbl;
7746 #else
7747   typedef double sqlite3_rtree_dbl;
7748 #endif
7749 
7750 /*
7751 ** Register a geometry callback named zGeom that can be used as part of an
7752 ** R-Tree geometry query as follows:
7753 **
7754 **   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
7755 */
7756 SQLITE_API int SQLITE_STDCALL sqlite3_rtree_geometry_callback(
7757   sqlite3 *db,
7758   const char *zGeom,
7759   int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
7760   void *pContext
7761 );
7762 
7763 
7764 /*
7765 ** A pointer to a structure of the following type is passed as the first
7766 ** argument to callbacks registered using rtree_geometry_callback().
7767 */
7768 struct sqlite3_rtree_geometry {
7769   void *pContext;                 /* Copy of pContext passed to s_r_g_c() */
7770   int nParam;                     /* Size of array aParam[] */
7771   sqlite3_rtree_dbl *aParam;      /* Parameters passed to SQL geom function */
7772   void *pUser;                    /* Callback implementation user data */
7773   void (*xDelUser)(void *);       /* Called by SQLite to clean up pUser */
7774 };
7775 
7776 /*
7777 ** Register a 2nd-generation geometry callback named zScore that can be
7778 ** used as part of an R-Tree geometry query as follows:
7779 **
7780 **   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
7781 */
7782 SQLITE_API int SQLITE_STDCALL sqlite3_rtree_query_callback(
7783   sqlite3 *db,
7784   const char *zQueryFunc,
7785   int (*xQueryFunc)(sqlite3_rtree_query_info*),
7786   void *pContext,
7787   void (*xDestructor)(void*)
7788 );
7789 
7790 
7791 /*
7792 ** A pointer to a structure of the following type is passed as the
7793 ** argument to scored geometry callback registered using
7794 ** sqlite3_rtree_query_callback().
7795 **
7796 ** Note that the first 5 fields of this structure are identical to
7797 ** sqlite3_rtree_geometry.  This structure is a subclass of
7798 ** sqlite3_rtree_geometry.
7799 */
7800 struct sqlite3_rtree_query_info {
7801   void *pContext;                   /* pContext from when function registered */
7802   int nParam;                       /* Number of function parameters */
7803   sqlite3_rtree_dbl *aParam;        /* value of function parameters */
7804   void *pUser;                      /* callback can use this, if desired */
7805   void (*xDelUser)(void*);          /* function to free pUser */
7806   sqlite3_rtree_dbl *aCoord;        /* Coordinates of node or entry to check */
7807   unsigned int *anQueue;            /* Number of pending entries in the queue */
7808   int nCoord;                       /* Number of coordinates */
7809   int iLevel;                       /* Level of current node or entry */
7810   int mxLevel;                      /* The largest iLevel value in the tree */
7811   sqlite3_int64 iRowid;             /* Rowid for current entry */
7812   sqlite3_rtree_dbl rParentScore;   /* Score of parent node */
7813   int eParentWithin;                /* Visibility of parent node */
7814   int eWithin;                      /* OUT: Visiblity */
7815   sqlite3_rtree_dbl rScore;         /* OUT: Write the score here */
7816 };
7817 
7818 /*
7819 ** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
7820 */
7821 #define NOT_WITHIN       0   /* Object completely outside of query region */
7822 #define PARTLY_WITHIN    1   /* Object partially overlaps query region */
7823 #define FULLY_WITHIN     2   /* Object fully contained within query region */
7824 
7825 
7826 #ifdef __cplusplus
7827 }  /* end of the 'extern "C"' block */
7828 #endif
7829 
7830 #endif  /* ifndef _SQLITE3RTREE_H_ */
7831 
7832