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 ** Add the ability to override 'extern' 47 */ 48 #ifndef SQLITE_EXTERN 49 # define SQLITE_EXTERN extern 50 #endif 51 52 #ifndef SQLITE_API 53 # define SQLITE_API 54 #endif 55 56 57 /* 58 ** These no-op macros are used in front of interfaces to mark those 59 ** interfaces as either deprecated or experimental. New applications 60 ** should not use deprecated interfaces - they are support for backwards 61 ** compatibility only. Application writers should be aware that 62 ** experimental interfaces are subject to change in point releases. 63 ** 64 ** These macros used to resolve to various kinds of compiler magic that 65 ** would generate warning messages when they were used. But that 66 ** compiler magic ended up generating such a flurry of bug reports 67 ** that we have taken it all out and gone back to using simple 68 ** noop macros. 69 */ 70 #define SQLITE_DEPRECATED 71 #define SQLITE_EXPERIMENTAL 72 73 /* 74 ** Ensure these symbols were not defined by some previous header file. 75 */ 76 #ifdef SQLITE_VERSION 77 # undef SQLITE_VERSION 78 #endif 79 #ifdef SQLITE_VERSION_NUMBER 80 # undef SQLITE_VERSION_NUMBER 81 #endif 82 83 /* 84 ** CAPI3REF: Compile-Time Library Version Numbers 85 ** 86 ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 87 ** evaluates to a string literal that is the SQLite version in the 88 ** format "X.Y.Z" where X is the major version number (always 3 for 89 ** SQLite3) and Y is the minor version number and Z is the release number.)^ 90 ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 91 ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 92 ** numbers used in [SQLITE_VERSION].)^ 93 ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 94 ** be larger than the release from which it is derived. Either Y will 95 ** be held constant and Z will be incremented or else Y will be incremented 96 ** and Z will be reset to zero. 97 ** 98 ** Since version 3.6.18, SQLite source code has been stored in the 99 ** <a href="http://www.fossil-scm.org/">Fossil configuration management 100 ** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 101 ** a string which identifies a particular check-in of SQLite 102 ** within its configuration management system. ^The SQLITE_SOURCE_ID 103 ** string contains the date and time of the check-in (UTC) and an SHA1 104 ** hash of the entire source tree. 105 ** 106 ** See also: [sqlite3_libversion()], 107 ** [sqlite3_libversion_number()], [sqlite3_sourceid()], 108 ** [sqlite_version()] and [sqlite_source_id()]. 109 */ 110 #define SQLITE_VERSION "3.7.17" 111 #define SQLITE_VERSION_NUMBER 3007017 112 #define SQLITE_SOURCE_ID "2013-05-20 00:56:22 118a3b35693b134d56ebd780123b7fd6f1497668" 113 114 /* 115 ** CAPI3REF: Run-Time Library Version Numbers 116 ** KEYWORDS: sqlite3_version, sqlite3_sourceid 117 ** 118 ** These interfaces provide the same information as the [SQLITE_VERSION], 119 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 120 ** but are associated with the library instead of the header file. ^(Cautious 121 ** programmers might include assert() statements in their application to 122 ** verify that values returned by these interfaces match the macros in 123 ** the header, and thus insure that the application is 124 ** compiled with matching library and header files. 125 ** 126 ** <blockquote><pre> 127 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 128 ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 129 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 130 ** </pre></blockquote>)^ 131 ** 132 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 133 ** macro. ^The sqlite3_libversion() function returns a pointer to the 134 ** to the sqlite3_version[] string constant. The sqlite3_libversion() 135 ** function is provided for use in DLLs since DLL users usually do not have 136 ** direct access to string constants within the DLL. ^The 137 ** sqlite3_libversion_number() function returns an integer equal to 138 ** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 139 ** a pointer to a string constant whose value is the same as the 140 ** [SQLITE_SOURCE_ID] C preprocessor macro. 141 ** 142 ** See also: [sqlite_version()] and [sqlite_source_id()]. 143 */ 144 SQLITE_API SQLITE_EXTERN const char sqlite3_version[]; 145 SQLITE_API const char *sqlite3_libversion(void); 146 SQLITE_API const char *sqlite3_sourceid(void); 147 SQLITE_API int sqlite3_libversion_number(void); 148 149 /* 150 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics 151 ** 152 ** ^The sqlite3_compileoption_used() function returns 0 or 1 153 ** indicating whether the specified option was defined at 154 ** compile time. ^The SQLITE_ prefix may be omitted from the 155 ** option name passed to sqlite3_compileoption_used(). 156 ** 157 ** ^The sqlite3_compileoption_get() function allows iterating 158 ** over the list of options that were defined at compile time by 159 ** returning the N-th compile time option string. ^If N is out of range, 160 ** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 161 ** prefix is omitted from any strings returned by 162 ** sqlite3_compileoption_get(). 163 ** 164 ** ^Support for the diagnostic functions sqlite3_compileoption_used() 165 ** and sqlite3_compileoption_get() may be omitted by specifying the 166 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 167 ** 168 ** See also: SQL functions [sqlite_compileoption_used()] and 169 ** [sqlite_compileoption_get()] and the [compile_options pragma]. 170 */ 171 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 172 SQLITE_API int sqlite3_compileoption_used(const char *zOptName); 173 SQLITE_API const char *sqlite3_compileoption_get(int N); 174 #endif 175 176 /* 177 ** CAPI3REF: Test To See If The Library Is Threadsafe 178 ** 179 ** ^The sqlite3_threadsafe() function returns zero if and only if 180 ** SQLite was compiled with mutexing code omitted due to the 181 ** [SQLITE_THREADSAFE] compile-time option being set to 0. 182 ** 183 ** SQLite can be compiled with or without mutexes. When 184 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 185 ** are enabled and SQLite is threadsafe. When the 186 ** [SQLITE_THREADSAFE] macro is 0, 187 ** the mutexes are omitted. Without the mutexes, it is not safe 188 ** to use SQLite concurrently from more than one thread. 189 ** 190 ** Enabling mutexes incurs a measurable performance penalty. 191 ** So if speed is of utmost importance, it makes sense to disable 192 ** the mutexes. But for maximum safety, mutexes should be enabled. 193 ** ^The default behavior is for mutexes to be enabled. 194 ** 195 ** This interface can be used by an application to make sure that the 196 ** version of SQLite that it is linking against was compiled with 197 ** the desired setting of the [SQLITE_THREADSAFE] macro. 198 ** 199 ** This interface only reports on the compile-time mutex setting 200 ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 201 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 202 ** can be fully or partially disabled using a call to [sqlite3_config()] 203 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 204 ** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the 205 ** sqlite3_threadsafe() function shows only the compile-time setting of 206 ** thread safety, not any run-time changes to that setting made by 207 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 208 ** is unchanged by calls to sqlite3_config().)^ 209 ** 210 ** See the [threading mode] documentation for additional information. 211 */ 212 SQLITE_API int sqlite3_threadsafe(void); 213 214 /* 215 ** CAPI3REF: Database Connection Handle 216 ** KEYWORDS: {database connection} {database connections} 217 ** 218 ** Each open SQLite database is represented by a pointer to an instance of 219 ** the opaque structure named "sqlite3". It is useful to think of an sqlite3 220 ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 221 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 222 ** and [sqlite3_close_v2()] are its destructors. There are many other 223 ** interfaces (such as 224 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 225 ** [sqlite3_busy_timeout()] to name but three) that are methods on an 226 ** sqlite3 object. 227 */ 228 typedef struct sqlite3 sqlite3; 229 230 /* 231 ** CAPI3REF: 64-Bit Integer Types 232 ** KEYWORDS: sqlite_int64 sqlite_uint64 233 ** 234 ** Because there is no cross-platform way to specify 64-bit integer types 235 ** SQLite includes typedefs for 64-bit signed and unsigned integers. 236 ** 237 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 238 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards 239 ** compatibility only. 240 ** 241 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values 242 ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 243 ** sqlite3_uint64 and sqlite_uint64 types can store integer values 244 ** between 0 and +18446744073709551615 inclusive. 245 */ 246 #ifdef SQLITE_INT64_TYPE 247 typedef SQLITE_INT64_TYPE sqlite_int64; 248 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 249 #elif defined(_MSC_VER) || defined(__BORLANDC__) 250 typedef __int64 sqlite_int64; 251 typedef unsigned __int64 sqlite_uint64; 252 #else 253 typedef long long int sqlite_int64; 254 typedef unsigned long long int sqlite_uint64; 255 #endif 256 typedef sqlite_int64 sqlite3_int64; 257 typedef sqlite_uint64 sqlite3_uint64; 258 259 /* 260 ** If compiling for a processor that lacks floating point support, 261 ** substitute integer for floating-point. 262 */ 263 #ifdef SQLITE_OMIT_FLOATING_POINT 264 # define double sqlite3_int64 265 #endif 266 267 /* 268 ** CAPI3REF: Closing A Database Connection 269 ** 270 ** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 271 ** for the [sqlite3] object. 272 ** ^Calls to sqlite3_close() and sqlite3_close_v2() return SQLITE_OK if 273 ** the [sqlite3] object is successfully destroyed and all associated 274 ** resources are deallocated. 275 ** 276 ** ^If the database connection is associated with unfinalized prepared 277 ** statements or unfinished sqlite3_backup objects then sqlite3_close() 278 ** will leave the database connection open and return [SQLITE_BUSY]. 279 ** ^If sqlite3_close_v2() is called with unfinalized prepared statements 280 ** and unfinished sqlite3_backups, then the database connection becomes 281 ** an unusable "zombie" which will automatically be deallocated when the 282 ** last prepared statement is finalized or the last sqlite3_backup is 283 ** finished. The sqlite3_close_v2() interface is intended for use with 284 ** host languages that are garbage collected, and where the order in which 285 ** destructors are called is arbitrary. 286 ** 287 ** Applications should [sqlite3_finalize | finalize] all [prepared statements], 288 ** [sqlite3_blob_close | close] all [BLOB handles], and 289 ** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 290 ** with the [sqlite3] object prior to attempting to close the object. ^If 291 ** sqlite3_close_v2() is called on a [database connection] that still has 292 ** outstanding [prepared statements], [BLOB handles], and/or 293 ** [sqlite3_backup] objects then it returns SQLITE_OK but the deallocation 294 ** of resources is deferred until all [prepared statements], [BLOB handles], 295 ** and [sqlite3_backup] objects are also destroyed. 296 ** 297 ** ^If an [sqlite3] object is destroyed while a transaction is open, 298 ** the transaction is automatically rolled back. 299 ** 300 ** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 301 ** must be either a NULL 302 ** pointer or an [sqlite3] object pointer obtained 303 ** from [sqlite3_open()], [sqlite3_open16()], or 304 ** [sqlite3_open_v2()], and not previously closed. 305 ** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 306 ** argument is a harmless no-op. 307 */ 308 SQLITE_API int sqlite3_close(sqlite3*); 309 SQLITE_API int sqlite3_close_v2(sqlite3*); 310 311 /* 312 ** The type for a callback function. 313 ** This is legacy and deprecated. It is included for historical 314 ** compatibility and is not documented. 315 */ 316 typedef int (*sqlite3_callback)(void*,int,char**, char**); 317 318 /* 319 ** CAPI3REF: One-Step Query Execution Interface 320 ** 321 ** The sqlite3_exec() interface is a convenience wrapper around 322 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 323 ** that allows an application to run multiple statements of SQL 324 ** without having to use a lot of C code. 325 ** 326 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 327 ** semicolon-separate SQL statements passed into its 2nd argument, 328 ** in the context of the [database connection] passed in as its 1st 329 ** argument. ^If the callback function of the 3rd argument to 330 ** sqlite3_exec() is not NULL, then it is invoked for each result row 331 ** coming out of the evaluated SQL statements. ^The 4th argument to 332 ** sqlite3_exec() is relayed through to the 1st argument of each 333 ** callback invocation. ^If the callback pointer to sqlite3_exec() 334 ** is NULL, then no callback is ever invoked and result rows are 335 ** ignored. 336 ** 337 ** ^If an error occurs while evaluating the SQL statements passed into 338 ** sqlite3_exec(), then execution of the current statement stops and 339 ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 340 ** is not NULL then any error message is written into memory obtained 341 ** from [sqlite3_malloc()] and passed back through the 5th parameter. 342 ** To avoid memory leaks, the application should invoke [sqlite3_free()] 343 ** on error message strings returned through the 5th parameter of 344 ** of sqlite3_exec() after the error message string is no longer needed. 345 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 346 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 347 ** NULL before returning. 348 ** 349 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 350 ** routine returns SQLITE_ABORT without invoking the callback again and 351 ** without running any subsequent SQL statements. 352 ** 353 ** ^The 2nd argument to the sqlite3_exec() callback function is the 354 ** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 355 ** callback is an array of pointers to strings obtained as if from 356 ** [sqlite3_column_text()], one for each column. ^If an element of a 357 ** result row is NULL then the corresponding string pointer for the 358 ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 359 ** sqlite3_exec() callback is an array of pointers to strings where each 360 ** entry represents the name of corresponding result column as obtained 361 ** from [sqlite3_column_name()]. 362 ** 363 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 364 ** to an empty string, or a pointer that contains only whitespace and/or 365 ** SQL comments, then no SQL statements are evaluated and the database 366 ** is not changed. 367 ** 368 ** Restrictions: 369 ** 370 ** <ul> 371 ** <li> The application must insure that the 1st parameter to sqlite3_exec() 372 ** is a valid and open [database connection]. 373 ** <li> The application must not close [database connection] specified by 374 ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 375 ** <li> The application must not modify the SQL statement text passed into 376 ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 377 ** </ul> 378 */ 379 SQLITE_API int sqlite3_exec( 380 sqlite3*, /* An open database */ 381 const char *sql, /* SQL to be evaluated */ 382 int (*callback)(void*,int,char**,char**), /* Callback function */ 383 void *, /* 1st argument to callback */ 384 char **errmsg /* Error msg written here */ 385 ); 386 387 /* 388 ** CAPI3REF: Result Codes 389 ** KEYWORDS: SQLITE_OK {error code} {error codes} 390 ** KEYWORDS: {result code} {result codes} 391 ** 392 ** Many SQLite functions return an integer result code from the set shown 393 ** here in order to indicate success or failure. 394 ** 395 ** New error codes may be added in future versions of SQLite. 396 ** 397 ** See also: [SQLITE_IOERR_READ | extended result codes], 398 ** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes]. 399 */ 400 #define SQLITE_OK 0 /* Successful result */ 401 /* beginning-of-error-codes */ 402 #define SQLITE_ERROR 1 /* SQL error or missing database */ 403 #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 404 #define SQLITE_PERM 3 /* Access permission denied */ 405 #define SQLITE_ABORT 4 /* Callback routine requested an abort */ 406 #define SQLITE_BUSY 5 /* The database file is locked */ 407 #define SQLITE_LOCKED 6 /* A table in the database is locked */ 408 #define SQLITE_NOMEM 7 /* A malloc() failed */ 409 #define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 410 #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 411 #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 412 #define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 413 #define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 414 #define SQLITE_FULL 13 /* Insertion failed because database is full */ 415 #define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 416 #define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 417 #define SQLITE_EMPTY 16 /* Database is empty */ 418 #define SQLITE_SCHEMA 17 /* The database schema changed */ 419 #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 420 #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 421 #define SQLITE_MISMATCH 20 /* Data type mismatch */ 422 #define SQLITE_MISUSE 21 /* Library used incorrectly */ 423 #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 424 #define SQLITE_AUTH 23 /* Authorization denied */ 425 #define SQLITE_FORMAT 24 /* Auxiliary database format error */ 426 #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 427 #define SQLITE_NOTADB 26 /* File opened that is not a database file */ 428 #define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 429 #define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 430 #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 431 #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 432 /* end-of-error-codes */ 433 434 /* 435 ** CAPI3REF: Extended Result Codes 436 ** KEYWORDS: {extended error code} {extended error codes} 437 ** KEYWORDS: {extended result code} {extended result codes} 438 ** 439 ** In its default configuration, SQLite API routines return one of 26 integer 440 ** [SQLITE_OK | result codes]. However, experience has shown that many of 441 ** these result codes are too coarse-grained. They do not provide as 442 ** much information about problems as programmers might like. In an effort to 443 ** address this, newer versions of SQLite (version 3.3.8 and later) include 444 ** support for additional result codes that provide more detailed information 445 ** about errors. The extended result codes are enabled or disabled 446 ** on a per database connection basis using the 447 ** [sqlite3_extended_result_codes()] API. 448 ** 449 ** Some of the available extended result codes are listed here. 450 ** One may expect the number of extended result codes will be expand 451 ** over time. Software that uses extended result codes should expect 452 ** to see new result codes in future releases of SQLite. 453 ** 454 ** The SQLITE_OK result code will never be extended. It will always 455 ** be exactly zero. 456 */ 457 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 458 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 459 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 460 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 461 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 462 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 463 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 464 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 465 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 466 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 467 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 468 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 469 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 470 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 471 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 472 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 473 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 474 #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 475 #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 476 #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 477 #define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 478 #define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 479 #define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 480 #define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 481 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 482 #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<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_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 487 #define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 488 #define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 489 #define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 490 #define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 491 #define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 492 #define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 493 #define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 494 #define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 495 #define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 496 #define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 497 #define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 498 #define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 499 #define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 500 #define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 501 #define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 502 503 /* 504 ** CAPI3REF: Flags For File Open Operations 505 ** 506 ** These bit values are intended for use in the 507 ** 3rd parameter to the [sqlite3_open_v2()] interface and 508 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 509 */ 510 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 511 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 512 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 513 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 514 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 515 #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 516 #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 517 #define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 518 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 519 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 520 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 521 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 522 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 523 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 524 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 525 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 526 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 527 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 528 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 529 #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 530 531 /* Reserved: 0x00F00000 */ 532 533 /* 534 ** CAPI3REF: Device Characteristics 535 ** 536 ** The xDeviceCharacteristics method of the [sqlite3_io_methods] 537 ** object returns an integer which is a vector of these 538 ** bit values expressing I/O characteristics of the mass storage 539 ** device that holds the file that the [sqlite3_io_methods] 540 ** refers to. 541 ** 542 ** The SQLITE_IOCAP_ATOMIC property means that all writes of 543 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 544 ** mean that writes of blocks that are nnn bytes in size and 545 ** are aligned to an address which is an integer multiple of 546 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 547 ** that when data is appended to a file, the data is appended 548 ** first then the size of the file is extended, never the other 549 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 550 ** information is written to disk in the same order as calls 551 ** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 552 ** after reboot following a crash or power loss, the only bytes in a 553 ** file that were written at the application level might have changed 554 ** and that adjacent bytes, even bytes within the same sector are 555 ** guaranteed to be unchanged. 556 */ 557 #define SQLITE_IOCAP_ATOMIC 0x00000001 558 #define SQLITE_IOCAP_ATOMIC512 0x00000002 559 #define SQLITE_IOCAP_ATOMIC1K 0x00000004 560 #define SQLITE_IOCAP_ATOMIC2K 0x00000008 561 #define SQLITE_IOCAP_ATOMIC4K 0x00000010 562 #define SQLITE_IOCAP_ATOMIC8K 0x00000020 563 #define SQLITE_IOCAP_ATOMIC16K 0x00000040 564 #define SQLITE_IOCAP_ATOMIC32K 0x00000080 565 #define SQLITE_IOCAP_ATOMIC64K 0x00000100 566 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200 567 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400 568 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 569 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 570 571 /* 572 ** CAPI3REF: File Locking Levels 573 ** 574 ** SQLite uses one of these integer values as the second 575 ** argument to calls it makes to the xLock() and xUnlock() methods 576 ** of an [sqlite3_io_methods] object. 577 */ 578 #define SQLITE_LOCK_NONE 0 579 #define SQLITE_LOCK_SHARED 1 580 #define SQLITE_LOCK_RESERVED 2 581 #define SQLITE_LOCK_PENDING 3 582 #define SQLITE_LOCK_EXCLUSIVE 4 583 584 /* 585 ** CAPI3REF: Synchronization Type Flags 586 ** 587 ** When SQLite invokes the xSync() method of an 588 ** [sqlite3_io_methods] object it uses a combination of 589 ** these integer values as the second argument. 590 ** 591 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 592 ** sync operation only needs to flush data to mass storage. Inode 593 ** information need not be flushed. If the lower four bits of the flag 594 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 595 ** If the lower four bits equal SQLITE_SYNC_FULL, that means 596 ** to use Mac OS X style fullsync instead of fsync(). 597 ** 598 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 599 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 600 ** settings. The [synchronous pragma] determines when calls to the 601 ** xSync VFS method occur and applies uniformly across all platforms. 602 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 603 ** energetic or rigorous or forceful the sync operations are and 604 ** only make a difference on Mac OSX for the default SQLite code. 605 ** (Third-party VFS implementations might also make the distinction 606 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 607 ** operating systems natively supported by SQLite, only Mac OSX 608 ** cares about the difference.) 609 */ 610 #define SQLITE_SYNC_NORMAL 0x00002 611 #define SQLITE_SYNC_FULL 0x00003 612 #define SQLITE_SYNC_DATAONLY 0x00010 613 614 /* 615 ** CAPI3REF: OS Interface Open File Handle 616 ** 617 ** An [sqlite3_file] object represents an open file in the 618 ** [sqlite3_vfs | OS interface layer]. Individual OS interface 619 ** implementations will 620 ** want to subclass this object by appending additional fields 621 ** for their own use. The pMethods entry is a pointer to an 622 ** [sqlite3_io_methods] object that defines methods for performing 623 ** I/O operations on the open file. 624 */ 625 typedef struct sqlite3_file sqlite3_file; 626 struct sqlite3_file { 627 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 628 }; 629 630 /* 631 ** CAPI3REF: OS Interface File Virtual Methods Object 632 ** 633 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an 634 ** [sqlite3_file] object (or, more commonly, a subclass of the 635 ** [sqlite3_file] object) with a pointer to an instance of this object. 636 ** This object defines the methods used to perform various operations 637 ** against the open file represented by the [sqlite3_file] object. 638 ** 639 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 640 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 641 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 642 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 643 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 644 ** to NULL. 645 ** 646 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 647 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 648 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 649 ** flag may be ORed in to indicate that only the data of the file 650 ** and not its inode needs to be synced. 651 ** 652 ** The integer values to xLock() and xUnlock() are one of 653 ** <ul> 654 ** <li> [SQLITE_LOCK_NONE], 655 ** <li> [SQLITE_LOCK_SHARED], 656 ** <li> [SQLITE_LOCK_RESERVED], 657 ** <li> [SQLITE_LOCK_PENDING], or 658 ** <li> [SQLITE_LOCK_EXCLUSIVE]. 659 ** </ul> 660 ** xLock() increases the lock. xUnlock() decreases the lock. 661 ** The xCheckReservedLock() method checks whether any database connection, 662 ** either in this process or in some other process, is holding a RESERVED, 663 ** PENDING, or EXCLUSIVE lock on the file. It returns true 664 ** if such a lock exists and false otherwise. 665 ** 666 ** The xFileControl() method is a generic interface that allows custom 667 ** VFS implementations to directly control an open file using the 668 ** [sqlite3_file_control()] interface. The second "op" argument is an 669 ** integer opcode. The third argument is a generic pointer intended to 670 ** point to a structure that may contain arguments or space in which to 671 ** write return values. Potential uses for xFileControl() might be 672 ** functions to enable blocking locks with timeouts, to change the 673 ** locking strategy (for example to use dot-file locks), to inquire 674 ** about the status of a lock, or to break stale locks. The SQLite 675 ** core reserves all opcodes less than 100 for its own use. 676 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 677 ** Applications that define a custom xFileControl method should use opcodes 678 ** greater than 100 to avoid conflicts. VFS implementations should 679 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not 680 ** recognize. 681 ** 682 ** The xSectorSize() method returns the sector size of the 683 ** device that underlies the file. The sector size is the 684 ** minimum write that can be performed without disturbing 685 ** other bytes in the file. The xDeviceCharacteristics() 686 ** method returns a bit vector describing behaviors of the 687 ** underlying device: 688 ** 689 ** <ul> 690 ** <li> [SQLITE_IOCAP_ATOMIC] 691 ** <li> [SQLITE_IOCAP_ATOMIC512] 692 ** <li> [SQLITE_IOCAP_ATOMIC1K] 693 ** <li> [SQLITE_IOCAP_ATOMIC2K] 694 ** <li> [SQLITE_IOCAP_ATOMIC4K] 695 ** <li> [SQLITE_IOCAP_ATOMIC8K] 696 ** <li> [SQLITE_IOCAP_ATOMIC16K] 697 ** <li> [SQLITE_IOCAP_ATOMIC32K] 698 ** <li> [SQLITE_IOCAP_ATOMIC64K] 699 ** <li> [SQLITE_IOCAP_SAFE_APPEND] 700 ** <li> [SQLITE_IOCAP_SEQUENTIAL] 701 ** </ul> 702 ** 703 ** The SQLITE_IOCAP_ATOMIC property means that all writes of 704 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 705 ** mean that writes of blocks that are nnn bytes in size and 706 ** are aligned to an address which is an integer multiple of 707 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 708 ** that when data is appended to a file, the data is appended 709 ** first then the size of the file is extended, never the other 710 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 711 ** information is written to disk in the same order as calls 712 ** to xWrite(). 713 ** 714 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 715 ** in the unread portions of the buffer with zeros. A VFS that 716 ** fails to zero-fill short reads might seem to work. However, 717 ** failure to zero-fill short reads will eventually lead to 718 ** database corruption. 719 */ 720 typedef struct sqlite3_io_methods sqlite3_io_methods; 721 struct sqlite3_io_methods { 722 int iVersion; 723 int (*xClose)(sqlite3_file*); 724 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 725 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 726 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 727 int (*xSync)(sqlite3_file*, int flags); 728 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 729 int (*xLock)(sqlite3_file*, int); 730 int (*xUnlock)(sqlite3_file*, int); 731 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 732 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 733 int (*xSectorSize)(sqlite3_file*); 734 int (*xDeviceCharacteristics)(sqlite3_file*); 735 /* Methods above are valid for version 1 */ 736 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 737 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 738 void (*xShmBarrier)(sqlite3_file*); 739 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 740 /* Methods above are valid for version 2 */ 741 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 742 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 743 /* Methods above are valid for version 3 */ 744 /* Additional methods may be added in future releases */ 745 }; 746 747 /* 748 ** CAPI3REF: Standard File Control Opcodes 749 ** 750 ** These integer constants are opcodes for the xFileControl method 751 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 752 ** interface. 753 ** 754 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 755 ** opcode causes the xFileControl method to write the current state of 756 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 757 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 758 ** into an integer that the pArg argument points to. This capability 759 ** is used during testing and only needs to be supported when SQLITE_TEST 760 ** is defined. 761 ** <ul> 762 ** <li>[[SQLITE_FCNTL_SIZE_HINT]] 763 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 764 ** layer a hint of how large the database file will grow to be during the 765 ** current transaction. This hint is not guaranteed to be accurate but it 766 ** is often close. The underlying VFS might choose to preallocate database 767 ** file space based on this hint in order to help writes to the database 768 ** file run faster. 769 ** 770 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 771 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 772 ** extends and truncates the database file in chunks of a size specified 773 ** by the user. The fourth argument to [sqlite3_file_control()] should 774 ** point to an integer (type int) containing the new chunk-size to use 775 ** for the nominated database. Allocating database file space in large 776 ** chunks (say 1MB at a time), may reduce file-system fragmentation and 777 ** improve performance on some systems. 778 ** 779 ** <li>[[SQLITE_FCNTL_FILE_POINTER]] 780 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 781 ** to the [sqlite3_file] object associated with a particular database 782 ** connection. See the [sqlite3_file_control()] documentation for 783 ** additional information. 784 ** 785 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 786 ** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by 787 ** SQLite and sent to all VFSes in place of a call to the xSync method 788 ** when the database connection has [PRAGMA synchronous] set to OFF.)^ 789 ** Some specialized VFSes need this signal in order to operate correctly 790 ** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most 791 ** VFSes do not need this signal and should silently ignore this opcode. 792 ** Applications should not call [sqlite3_file_control()] with this 793 ** opcode as doing so may disrupt the operation of the specialized VFSes 794 ** that do require it. 795 ** 796 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 797 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 798 ** retry counts and intervals for certain disk I/O operations for the 799 ** windows [VFS] in order to provide robustness in the presence of 800 ** anti-virus programs. By default, the windows VFS will retry file read, 801 ** file write, and file delete operations up to 10 times, with a delay 802 ** of 25 milliseconds before the first retry and with the delay increasing 803 ** by an additional 25 milliseconds with each subsequent retry. This 804 ** opcode allows these two values (10 retries and 25 milliseconds of delay) 805 ** to be adjusted. The values are changed for all database connections 806 ** within the same process. The argument is a pointer to an array of two 807 ** integers where the first integer i the new retry count and the second 808 ** integer is the delay. If either integer is negative, then the setting 809 ** is not changed but instead the prior value of that setting is written 810 ** into the array entry, allowing the current retry settings to be 811 ** interrogated. The zDbName parameter is ignored. 812 ** 813 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 814 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 815 ** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 816 ** write ahead log and shared memory files used for transaction control 817 ** are automatically deleted when the latest connection to the database 818 ** closes. Setting persistent WAL mode causes those files to persist after 819 ** close. Persisting the files is useful when other processes that do not 820 ** have write permission on the directory containing the database file want 821 ** to read the database file, as the WAL and shared memory files must exist 822 ** in order for the database to be readable. The fourth parameter to 823 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 824 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 825 ** WAL mode. If the integer is -1, then it is overwritten with the current 826 ** WAL persistence setting. 827 ** 828 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 829 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 830 ** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 831 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 832 ** xDeviceCharacteristics methods. The fourth parameter to 833 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 834 ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 835 ** mode. If the integer is -1, then it is overwritten with the current 836 ** zero-damage mode setting. 837 ** 838 ** <li>[[SQLITE_FCNTL_OVERWRITE]] 839 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 840 ** a write transaction to indicate that, unless it is rolled back for some 841 ** reason, the entire database file will be overwritten by the current 842 ** transaction. This is used by VACUUM operations. 843 ** 844 ** <li>[[SQLITE_FCNTL_VFSNAME]] 845 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 846 ** all [VFSes] in the VFS stack. The names are of all VFS shims and the 847 ** final bottom-level VFS are written into memory obtained from 848 ** [sqlite3_malloc()] and the result is stored in the char* variable 849 ** that the fourth parameter of [sqlite3_file_control()] points to. 850 ** The caller is responsible for freeing the memory when done. As with 851 ** all file-control actions, there is no guarantee that this will actually 852 ** do anything. Callers should initialize the char* variable to a NULL 853 ** pointer in case this file-control is not implemented. This file-control 854 ** is intended for diagnostic use only. 855 ** 856 ** <li>[[SQLITE_FCNTL_PRAGMA]] 857 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 858 ** file control is sent to the open [sqlite3_file] object corresponding 859 ** to the database file to which the pragma statement refers. ^The argument 860 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 861 ** pointers to strings (char**) in which the second element of the array 862 ** is the name of the pragma and the third element is the argument to the 863 ** pragma or NULL if the pragma has no argument. ^The handler for an 864 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 865 ** of the char** argument point to a string obtained from [sqlite3_mprintf()] 866 ** or the equivalent and that string will become the result of the pragma or 867 ** the error message if the pragma fails. ^If the 868 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 869 ** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 870 ** file control returns [SQLITE_OK], then the parser assumes that the 871 ** VFS has handled the PRAGMA itself and the parser generates a no-op 872 ** prepared statement. ^If the [SQLITE_FCNTL_PRAGMA] file control returns 873 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 874 ** that the VFS encountered an error while handling the [PRAGMA] and the 875 ** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 876 ** file control occurs at the beginning of pragma statement analysis and so 877 ** it is able to override built-in [PRAGMA] statements. 878 ** 879 ** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 880 ** ^The [SQLITE_FCNTL_BUSYHANDLER] 881 ** file-control may be invoked by SQLite on the database file handle 882 ** shortly after it is opened in order to provide a custom VFS with access 883 ** to the connections busy-handler callback. The argument is of type (void **) 884 ** - an array of two (void *) values. The first (void *) actually points 885 ** to a function of type (int (*)(void *)). In order to invoke the connections 886 ** busy-handler, this function should be invoked with the second (void *) in 887 ** the array as the only argument. If it returns non-zero, then the operation 888 ** should be retried. If it returns zero, the custom VFS should abandon the 889 ** current operation. 890 ** 891 ** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 892 ** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 893 ** to have SQLite generate a 894 ** temporary filename using the same algorithm that is followed to generate 895 ** temporary filenames for TEMP tables and other internal uses. The 896 ** argument should be a char** which will be filled with the filename 897 ** written into memory obtained from [sqlite3_malloc()]. The caller should 898 ** invoke [sqlite3_free()] on the result to avoid a memory leak. 899 ** 900 ** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 901 ** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 902 ** maximum number of bytes that will be used for memory-mapped I/O. 903 ** The argument is a pointer to a value of type sqlite3_int64 that 904 ** is an advisory maximum number of bytes in the file to memory map. The 905 ** pointer is overwritten with the old value. The limit is not changed if 906 ** the value originally pointed to is negative, and so the current limit 907 ** can be queried by passing in a pointer to a negative number. This 908 ** file-control is used internally to implement [PRAGMA mmap_size]. 909 ** 910 ** </ul> 911 */ 912 #define SQLITE_FCNTL_LOCKSTATE 1 913 #define SQLITE_GET_LOCKPROXYFILE 2 914 #define SQLITE_SET_LOCKPROXYFILE 3 915 #define SQLITE_LAST_ERRNO 4 916 #define SQLITE_FCNTL_SIZE_HINT 5 917 #define SQLITE_FCNTL_CHUNK_SIZE 6 918 #define SQLITE_FCNTL_FILE_POINTER 7 919 #define SQLITE_FCNTL_SYNC_OMITTED 8 920 #define SQLITE_FCNTL_WIN32_AV_RETRY 9 921 #define SQLITE_FCNTL_PERSIST_WAL 10 922 #define SQLITE_FCNTL_OVERWRITE 11 923 #define SQLITE_FCNTL_VFSNAME 12 924 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 925 #define SQLITE_FCNTL_PRAGMA 14 926 #define SQLITE_FCNTL_BUSYHANDLER 15 927 #define SQLITE_FCNTL_TEMPFILENAME 16 928 #define SQLITE_FCNTL_MMAP_SIZE 18 929 930 /* 931 ** CAPI3REF: Mutex Handle 932 ** 933 ** The mutex module within SQLite defines [sqlite3_mutex] to be an 934 ** abstract type for a mutex object. The SQLite core never looks 935 ** at the internal representation of an [sqlite3_mutex]. It only 936 ** deals with pointers to the [sqlite3_mutex] object. 937 ** 938 ** Mutexes are created using [sqlite3_mutex_alloc()]. 939 */ 940 typedef struct sqlite3_mutex sqlite3_mutex; 941 942 /* 943 ** CAPI3REF: OS Interface Object 944 ** 945 ** An instance of the sqlite3_vfs object defines the interface between 946 ** the SQLite core and the underlying operating system. The "vfs" 947 ** in the name of the object stands for "virtual file system". See 948 ** the [VFS | VFS documentation] for further information. 949 ** 950 ** The value of the iVersion field is initially 1 but may be larger in 951 ** future versions of SQLite. Additional fields may be appended to this 952 ** object when the iVersion value is increased. Note that the structure 953 ** of the sqlite3_vfs object changes in the transaction between 954 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 955 ** modified. 956 ** 957 ** The szOsFile field is the size of the subclassed [sqlite3_file] 958 ** structure used by this VFS. mxPathname is the maximum length of 959 ** a pathname in this VFS. 960 ** 961 ** Registered sqlite3_vfs objects are kept on a linked list formed by 962 ** the pNext pointer. The [sqlite3_vfs_register()] 963 ** and [sqlite3_vfs_unregister()] interfaces manage this list 964 ** in a thread-safe way. The [sqlite3_vfs_find()] interface 965 ** searches the list. Neither the application code nor the VFS 966 ** implementation should use the pNext pointer. 967 ** 968 ** The pNext field is the only field in the sqlite3_vfs 969 ** structure that SQLite will ever modify. SQLite will only access 970 ** or modify this field while holding a particular static mutex. 971 ** The application should never modify anything within the sqlite3_vfs 972 ** object once the object has been registered. 973 ** 974 ** The zName field holds the name of the VFS module. The name must 975 ** be unique across all VFS modules. 976 ** 977 ** [[sqlite3_vfs.xOpen]] 978 ** ^SQLite guarantees that the zFilename parameter to xOpen 979 ** is either a NULL pointer or string obtained 980 ** from xFullPathname() with an optional suffix added. 981 ** ^If a suffix is added to the zFilename parameter, it will 982 ** consist of a single "-" character followed by no more than 983 ** 11 alphanumeric and/or "-" characters. 984 ** ^SQLite further guarantees that 985 ** the string will be valid and unchanged until xClose() is 986 ** called. Because of the previous sentence, 987 ** the [sqlite3_file] can safely store a pointer to the 988 ** filename if it needs to remember the filename for some reason. 989 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen 990 ** must invent its own temporary name for the file. ^Whenever the 991 ** xFilename parameter is NULL it will also be the case that the 992 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 993 ** 994 ** The flags argument to xOpen() includes all bits set in 995 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 996 ** or [sqlite3_open16()] is used, then flags includes at least 997 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 998 ** If xOpen() opens a file read-only then it sets *pOutFlags to 999 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1000 ** 1001 ** ^(SQLite will also add one of the following flags to the xOpen() 1002 ** call, depending on the object being opened: 1003 ** 1004 ** <ul> 1005 ** <li> [SQLITE_OPEN_MAIN_DB] 1006 ** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1007 ** <li> [SQLITE_OPEN_TEMP_DB] 1008 ** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1009 ** <li> [SQLITE_OPEN_TRANSIENT_DB] 1010 ** <li> [SQLITE_OPEN_SUBJOURNAL] 1011 ** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1012 ** <li> [SQLITE_OPEN_WAL] 1013 ** </ul>)^ 1014 ** 1015 ** The file I/O implementation can use the object type flags to 1016 ** change the way it deals with files. For example, an application 1017 ** that does not care about crash recovery or rollback might make 1018 ** the open of a journal file a no-op. Writes to this journal would 1019 ** also be no-ops, and any attempt to read the journal would return 1020 ** SQLITE_IOERR. Or the implementation might recognize that a database 1021 ** file will be doing page-aligned sector reads and writes in a random 1022 ** order and set up its I/O subsystem accordingly. 1023 ** 1024 ** SQLite might also add one of the following flags to the xOpen method: 1025 ** 1026 ** <ul> 1027 ** <li> [SQLITE_OPEN_DELETEONCLOSE] 1028 ** <li> [SQLITE_OPEN_EXCLUSIVE] 1029 ** </ul> 1030 ** 1031 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1032 ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1033 ** will be set for TEMP databases and their journals, transient 1034 ** databases, and subjournals. 1035 ** 1036 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1037 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1038 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1039 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1040 ** SQLITE_OPEN_CREATE, is used to indicate that file should always 1041 ** be created, and that it is an error if it already exists. 1042 ** It is <i>not</i> used to indicate the file should be opened 1043 ** for exclusive access. 1044 ** 1045 ** ^At least szOsFile bytes of memory are allocated by SQLite 1046 ** to hold the [sqlite3_file] structure passed as the third 1047 ** argument to xOpen. The xOpen method does not have to 1048 ** allocate the structure; it should just fill it in. Note that 1049 ** the xOpen method must set the sqlite3_file.pMethods to either 1050 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1051 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1052 ** element will be valid after xOpen returns regardless of the success 1053 ** or failure of the xOpen call. 1054 ** 1055 ** [[sqlite3_vfs.xAccess]] 1056 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1057 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1058 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1059 ** to test whether a file is at least readable. The file can be a 1060 ** directory. 1061 ** 1062 ** ^SQLite will always allocate at least mxPathname+1 bytes for the 1063 ** output buffer xFullPathname. The exact size of the output buffer 1064 ** is also passed as a parameter to both methods. If the output buffer 1065 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1066 ** handled as a fatal error by SQLite, vfs implementations should endeavor 1067 ** to prevent this by setting mxPathname to a sufficiently large value. 1068 ** 1069 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1070 ** interfaces are not strictly a part of the filesystem, but they are 1071 ** included in the VFS structure for completeness. 1072 ** The xRandomness() function attempts to return nBytes bytes 1073 ** of good-quality randomness into zOut. The return value is 1074 ** the actual number of bytes of randomness obtained. 1075 ** The xSleep() method causes the calling thread to sleep for at 1076 ** least the number of microseconds given. ^The xCurrentTime() 1077 ** method returns a Julian Day Number for the current date and time as 1078 ** a floating point value. 1079 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1080 ** Day Number multiplied by 86400000 (the number of milliseconds in 1081 ** a 24-hour day). 1082 ** ^SQLite will use the xCurrentTimeInt64() method to get the current 1083 ** date and time if that method is available (if iVersion is 2 or 1084 ** greater and the function pointer is not NULL) and will fall back 1085 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1086 ** 1087 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1088 ** are not used by the SQLite core. These optional interfaces are provided 1089 ** by some VFSes to facilitate testing of the VFS code. By overriding 1090 ** system calls with functions under its control, a test program can 1091 ** simulate faults and error conditions that would otherwise be difficult 1092 ** or impossible to induce. The set of system calls that can be overridden 1093 ** varies from one VFS to another, and from one version of the same VFS to the 1094 ** next. Applications that use these interfaces must be prepared for any 1095 ** or all of these interfaces to be NULL or for their behavior to change 1096 ** from one release to the next. Applications must not attempt to access 1097 ** any of these methods if the iVersion of the VFS is less than 3. 1098 */ 1099 typedef struct sqlite3_vfs sqlite3_vfs; 1100 typedef void (*sqlite3_syscall_ptr)(void); 1101 struct sqlite3_vfs { 1102 int iVersion; /* Structure version number (currently 3) */ 1103 int szOsFile; /* Size of subclassed sqlite3_file */ 1104 int mxPathname; /* Maximum file pathname length */ 1105 sqlite3_vfs *pNext; /* Next registered VFS */ 1106 const char *zName; /* Name of this virtual file system */ 1107 void *pAppData; /* Pointer to application-specific data */ 1108 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1109 int flags, int *pOutFlags); 1110 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1111 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1112 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1113 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1114 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1115 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1116 void (*xDlClose)(sqlite3_vfs*, void*); 1117 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1118 int (*xSleep)(sqlite3_vfs*, int microseconds); 1119 int (*xCurrentTime)(sqlite3_vfs*, double*); 1120 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1121 /* 1122 ** The methods above are in version 1 of the sqlite_vfs object 1123 ** definition. Those that follow are added in version 2 or later 1124 */ 1125 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1126 /* 1127 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1128 ** Those below are for version 3 and greater. 1129 */ 1130 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1131 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1132 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1133 /* 1134 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1135 ** New fields may be appended in figure versions. The iVersion 1136 ** value will increment whenever this happens. 1137 */ 1138 }; 1139 1140 /* 1141 ** CAPI3REF: Flags for the xAccess VFS method 1142 ** 1143 ** These integer constants can be used as the third parameter to 1144 ** the xAccess method of an [sqlite3_vfs] object. They determine 1145 ** what kind of permissions the xAccess method is looking for. 1146 ** With SQLITE_ACCESS_EXISTS, the xAccess method 1147 ** simply checks whether the file exists. 1148 ** With SQLITE_ACCESS_READWRITE, the xAccess method 1149 ** checks whether the named directory is both readable and writable 1150 ** (in other words, if files can be added, removed, and renamed within 1151 ** the directory). 1152 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1153 ** [temp_store_directory pragma], though this could change in a future 1154 ** release of SQLite. 1155 ** With SQLITE_ACCESS_READ, the xAccess method 1156 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1157 ** currently unused, though it might be used in a future release of 1158 ** SQLite. 1159 */ 1160 #define SQLITE_ACCESS_EXISTS 0 1161 #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1162 #define SQLITE_ACCESS_READ 2 /* Unused */ 1163 1164 /* 1165 ** CAPI3REF: Flags for the xShmLock VFS method 1166 ** 1167 ** These integer constants define the various locking operations 1168 ** allowed by the xShmLock method of [sqlite3_io_methods]. The 1169 ** following are the only legal combinations of flags to the 1170 ** xShmLock method: 1171 ** 1172 ** <ul> 1173 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1174 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1175 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1176 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1177 ** </ul> 1178 ** 1179 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1180 ** was given no the corresponding lock. 1181 ** 1182 ** The xShmLock method can transition between unlocked and SHARED or 1183 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1184 ** and EXCLUSIVE. 1185 */ 1186 #define SQLITE_SHM_UNLOCK 1 1187 #define SQLITE_SHM_LOCK 2 1188 #define SQLITE_SHM_SHARED 4 1189 #define SQLITE_SHM_EXCLUSIVE 8 1190 1191 /* 1192 ** CAPI3REF: Maximum xShmLock index 1193 ** 1194 ** The xShmLock method on [sqlite3_io_methods] may use values 1195 ** between 0 and this upper bound as its "offset" argument. 1196 ** The SQLite core will never attempt to acquire or release a 1197 ** lock outside of this range 1198 */ 1199 #define SQLITE_SHM_NLOCK 8 1200 1201 1202 /* 1203 ** CAPI3REF: Initialize The SQLite Library 1204 ** 1205 ** ^The sqlite3_initialize() routine initializes the 1206 ** SQLite library. ^The sqlite3_shutdown() routine 1207 ** deallocates any resources that were allocated by sqlite3_initialize(). 1208 ** These routines are designed to aid in process initialization and 1209 ** shutdown on embedded systems. Workstation applications using 1210 ** SQLite normally do not need to invoke either of these routines. 1211 ** 1212 ** A call to sqlite3_initialize() is an "effective" call if it is 1213 ** the first time sqlite3_initialize() is invoked during the lifetime of 1214 ** the process, or if it is the first time sqlite3_initialize() is invoked 1215 ** following a call to sqlite3_shutdown(). ^(Only an effective call 1216 ** of sqlite3_initialize() does any initialization. All other calls 1217 ** are harmless no-ops.)^ 1218 ** 1219 ** A call to sqlite3_shutdown() is an "effective" call if it is the first 1220 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1221 ** an effective call to sqlite3_shutdown() does any deinitialization. 1222 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1223 ** 1224 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1225 ** is not. The sqlite3_shutdown() interface must only be called from a 1226 ** single thread. All open [database connections] must be closed and all 1227 ** other SQLite resources must be deallocated prior to invoking 1228 ** sqlite3_shutdown(). 1229 ** 1230 ** Among other things, ^sqlite3_initialize() will invoke 1231 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1232 ** will invoke sqlite3_os_end(). 1233 ** 1234 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1235 ** ^If for some reason, sqlite3_initialize() is unable to initialize 1236 ** the library (perhaps it is unable to allocate a needed resource such 1237 ** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1238 ** 1239 ** ^The sqlite3_initialize() routine is called internally by many other 1240 ** SQLite interfaces so that an application usually does not need to 1241 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1242 ** calls sqlite3_initialize() so the SQLite library will be automatically 1243 ** initialized when [sqlite3_open()] is called if it has not be initialized 1244 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1245 ** compile-time option, then the automatic calls to sqlite3_initialize() 1246 ** are omitted and the application must call sqlite3_initialize() directly 1247 ** prior to using any other SQLite interface. For maximum portability, 1248 ** it is recommended that applications always invoke sqlite3_initialize() 1249 ** directly prior to using any other SQLite interface. Future releases 1250 ** of SQLite may require this. In other words, the behavior exhibited 1251 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1252 ** default behavior in some future release of SQLite. 1253 ** 1254 ** The sqlite3_os_init() routine does operating-system specific 1255 ** initialization of the SQLite library. The sqlite3_os_end() 1256 ** routine undoes the effect of sqlite3_os_init(). Typical tasks 1257 ** performed by these routines include allocation or deallocation 1258 ** of static resources, initialization of global variables, 1259 ** setting up a default [sqlite3_vfs] module, or setting up 1260 ** a default configuration using [sqlite3_config()]. 1261 ** 1262 ** The application should never invoke either sqlite3_os_init() 1263 ** or sqlite3_os_end() directly. The application should only invoke 1264 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1265 ** interface is called automatically by sqlite3_initialize() and 1266 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1267 ** implementations for sqlite3_os_init() and sqlite3_os_end() 1268 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1269 ** When [custom builds | built for other platforms] 1270 ** (using the [SQLITE_OS_OTHER=1] compile-time 1271 ** option) the application must supply a suitable implementation for 1272 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1273 ** implementation of sqlite3_os_init() or sqlite3_os_end() 1274 ** must return [SQLITE_OK] on success and some other [error code] upon 1275 ** failure. 1276 */ 1277 SQLITE_API int sqlite3_initialize(void); 1278 SQLITE_API int sqlite3_shutdown(void); 1279 SQLITE_API int sqlite3_os_init(void); 1280 SQLITE_API int sqlite3_os_end(void); 1281 1282 /* 1283 ** CAPI3REF: Configuring The SQLite Library 1284 ** 1285 ** The sqlite3_config() interface is used to make global configuration 1286 ** changes to SQLite in order to tune SQLite to the specific needs of 1287 ** the application. The default configuration is recommended for most 1288 ** applications and so this routine is usually not necessary. It is 1289 ** provided to support rare applications with unusual needs. 1290 ** 1291 ** The sqlite3_config() interface is not threadsafe. The application 1292 ** must insure that no other SQLite interfaces are invoked by other 1293 ** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1294 ** may only be invoked prior to library initialization using 1295 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1296 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1297 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1298 ** Note, however, that ^sqlite3_config() can be called as part of the 1299 ** implementation of an application-defined [sqlite3_os_init()]. 1300 ** 1301 ** The first argument to sqlite3_config() is an integer 1302 ** [configuration option] that determines 1303 ** what property of SQLite is to be configured. Subsequent arguments 1304 ** vary depending on the [configuration option] 1305 ** in the first argument. 1306 ** 1307 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1308 ** ^If the option is unknown or SQLite is unable to set the option 1309 ** then this routine returns a non-zero [error code]. 1310 */ 1311 SQLITE_API int sqlite3_config(int, ...); 1312 1313 /* 1314 ** CAPI3REF: Configure database connections 1315 ** 1316 ** The sqlite3_db_config() interface is used to make configuration 1317 ** changes to a [database connection]. The interface is similar to 1318 ** [sqlite3_config()] except that the changes apply to a single 1319 ** [database connection] (specified in the first argument). 1320 ** 1321 ** The second argument to sqlite3_db_config(D,V,...) is the 1322 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1323 ** that indicates what aspect of the [database connection] is being configured. 1324 ** Subsequent arguments vary depending on the configuration verb. 1325 ** 1326 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1327 ** the call is considered successful. 1328 */ 1329 SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...); 1330 1331 /* 1332 ** CAPI3REF: Memory Allocation Routines 1333 ** 1334 ** An instance of this object defines the interface between SQLite 1335 ** and low-level memory allocation routines. 1336 ** 1337 ** This object is used in only one place in the SQLite interface. 1338 ** A pointer to an instance of this object is the argument to 1339 ** [sqlite3_config()] when the configuration option is 1340 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1341 ** By creating an instance of this object 1342 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1343 ** during configuration, an application can specify an alternative 1344 ** memory allocation subsystem for SQLite to use for all of its 1345 ** dynamic memory needs. 1346 ** 1347 ** Note that SQLite comes with several [built-in memory allocators] 1348 ** that are perfectly adequate for the overwhelming majority of applications 1349 ** and that this object is only useful to a tiny minority of applications 1350 ** with specialized memory allocation requirements. This object is 1351 ** also used during testing of SQLite in order to specify an alternative 1352 ** memory allocator that simulates memory out-of-memory conditions in 1353 ** order to verify that SQLite recovers gracefully from such 1354 ** conditions. 1355 ** 1356 ** The xMalloc, xRealloc, and xFree methods must work like the 1357 ** malloc(), realloc() and free() functions from the standard C library. 1358 ** ^SQLite guarantees that the second argument to 1359 ** xRealloc is always a value returned by a prior call to xRoundup. 1360 ** 1361 ** xSize should return the allocated size of a memory allocation 1362 ** previously obtained from xMalloc or xRealloc. The allocated size 1363 ** is always at least as big as the requested size but may be larger. 1364 ** 1365 ** The xRoundup method returns what would be the allocated size of 1366 ** a memory allocation given a particular requested size. Most memory 1367 ** allocators round up memory allocations at least to the next multiple 1368 ** of 8. Some allocators round up to a larger multiple or to a power of 2. 1369 ** Every memory allocation request coming in through [sqlite3_malloc()] 1370 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1371 ** that causes the corresponding memory allocation to fail. 1372 ** 1373 ** The xInit method initializes the memory allocator. (For example, 1374 ** it might allocate any require mutexes or initialize internal data 1375 ** structures. The xShutdown method is invoked (indirectly) by 1376 ** [sqlite3_shutdown()] and should deallocate any resources acquired 1377 ** by xInit. The pAppData pointer is used as the only parameter to 1378 ** xInit and xShutdown. 1379 ** 1380 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1381 ** the xInit method, so the xInit method need not be threadsafe. The 1382 ** xShutdown method is only called from [sqlite3_shutdown()] so it does 1383 ** not need to be threadsafe either. For all other methods, SQLite 1384 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1385 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1386 ** it is by default) and so the methods are automatically serialized. 1387 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1388 ** methods must be threadsafe or else make their own arrangements for 1389 ** serialization. 1390 ** 1391 ** SQLite will never invoke xInit() more than once without an intervening 1392 ** call to xShutdown(). 1393 */ 1394 typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1395 struct sqlite3_mem_methods { 1396 void *(*xMalloc)(int); /* Memory allocation function */ 1397 void (*xFree)(void*); /* Free a prior allocation */ 1398 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1399 int (*xSize)(void*); /* Return the size of an allocation */ 1400 int (*xRoundup)(int); /* Round up request size to allocation size */ 1401 int (*xInit)(void*); /* Initialize the memory allocator */ 1402 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1403 void *pAppData; /* Argument to xInit() and xShutdown() */ 1404 }; 1405 1406 /* 1407 ** CAPI3REF: Configuration Options 1408 ** KEYWORDS: {configuration option} 1409 ** 1410 ** These constants are the available integer configuration options that 1411 ** can be passed as the first argument to the [sqlite3_config()] interface. 1412 ** 1413 ** New configuration options may be added in future releases of SQLite. 1414 ** Existing configuration options might be discontinued. Applications 1415 ** should check the return code from [sqlite3_config()] to make sure that 1416 ** the call worked. The [sqlite3_config()] interface will return a 1417 ** non-zero [error code] if a discontinued or unsupported configuration option 1418 ** is invoked. 1419 ** 1420 ** <dl> 1421 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1422 ** <dd>There are no arguments to this option. ^This option sets the 1423 ** [threading mode] to Single-thread. In other words, it disables 1424 ** all mutexing and puts SQLite into a mode where it can only be used 1425 ** by a single thread. ^If SQLite is compiled with 1426 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1427 ** it is not possible to change the [threading mode] from its default 1428 ** value of Single-thread and so [sqlite3_config()] will return 1429 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1430 ** configuration option.</dd> 1431 ** 1432 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1433 ** <dd>There are no arguments to this option. ^This option sets the 1434 ** [threading mode] to Multi-thread. In other words, it disables 1435 ** mutexing on [database connection] and [prepared statement] objects. 1436 ** The application is responsible for serializing access to 1437 ** [database connections] and [prepared statements]. But other mutexes 1438 ** are enabled so that SQLite will be safe to use in a multi-threaded 1439 ** environment as long as no two threads attempt to use the same 1440 ** [database connection] at the same time. ^If SQLite is compiled with 1441 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1442 ** it is not possible to set the Multi-thread [threading mode] and 1443 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1444 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1445 ** 1446 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1447 ** <dd>There are no arguments to this option. ^This option sets the 1448 ** [threading mode] to Serialized. In other words, this option enables 1449 ** all mutexes including the recursive 1450 ** mutexes on [database connection] and [prepared statement] objects. 1451 ** In this mode (which is the default when SQLite is compiled with 1452 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1453 ** to [database connections] and [prepared statements] so that the 1454 ** application is free to use the same [database connection] or the 1455 ** same [prepared statement] in different threads at the same time. 1456 ** ^If SQLite is compiled with 1457 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1458 ** it is not possible to set the Serialized [threading mode] and 1459 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1460 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1461 ** 1462 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1463 ** <dd> ^(This option takes a single argument which is a pointer to an 1464 ** instance of the [sqlite3_mem_methods] structure. The argument specifies 1465 ** alternative low-level memory allocation routines to be used in place of 1466 ** the memory allocation routines built into SQLite.)^ ^SQLite makes 1467 ** its own private copy of the content of the [sqlite3_mem_methods] structure 1468 ** before the [sqlite3_config()] call returns.</dd> 1469 ** 1470 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1471 ** <dd> ^(This option takes a single argument which is a pointer to an 1472 ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1473 ** structure is filled with the currently defined memory allocation routines.)^ 1474 ** This option can be used to overload the default memory allocation 1475 ** routines with a wrapper that simulations memory allocation failure or 1476 ** tracks memory usage, for example. </dd> 1477 ** 1478 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1479 ** <dd> ^This option takes single argument of type int, interpreted as a 1480 ** boolean, which enables or disables the collection of memory allocation 1481 ** statistics. ^(When memory allocation statistics are disabled, the 1482 ** following SQLite interfaces become non-operational: 1483 ** <ul> 1484 ** <li> [sqlite3_memory_used()] 1485 ** <li> [sqlite3_memory_highwater()] 1486 ** <li> [sqlite3_soft_heap_limit64()] 1487 ** <li> [sqlite3_status()] 1488 ** </ul>)^ 1489 ** ^Memory allocation statistics are enabled by default unless SQLite is 1490 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1491 ** allocation statistics are disabled by default. 1492 ** </dd> 1493 ** 1494 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1495 ** <dd> ^This option specifies a static memory buffer that SQLite can use for 1496 ** scratch memory. There are three arguments: A pointer an 8-byte 1497 ** aligned memory buffer from which the scratch allocations will be 1498 ** drawn, the size of each scratch allocation (sz), 1499 ** and the maximum number of scratch allocations (N). The sz 1500 ** argument must be a multiple of 16. 1501 ** The first argument must be a pointer to an 8-byte aligned buffer 1502 ** of at least sz*N bytes of memory. 1503 ** ^SQLite will use no more than two scratch buffers per thread. So 1504 ** N should be set to twice the expected maximum number of threads. 1505 ** ^SQLite will never require a scratch buffer that is more than 6 1506 ** times the database page size. ^If SQLite needs needs additional 1507 ** scratch memory beyond what is provided by this configuration option, then 1508 ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1509 ** 1510 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1511 ** <dd> ^This option specifies a static memory buffer that SQLite can use for 1512 ** the database page cache with the default page cache implementation. 1513 ** This configuration should not be used if an application-define page 1514 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option. 1515 ** There are three arguments to this option: A pointer to 8-byte aligned 1516 ** memory, the size of each page buffer (sz), and the number of pages (N). 1517 ** The sz argument should be the size of the largest database page 1518 ** (a power of two between 512 and 32768) plus a little extra for each 1519 ** page header. ^The page header size is 20 to 40 bytes depending on 1520 ** the host architecture. ^It is harmless, apart from the wasted memory, 1521 ** to make sz a little too large. The first 1522 ** argument should point to an allocation of at least sz*N bytes of memory. 1523 ** ^SQLite will use the memory provided by the first argument to satisfy its 1524 ** memory needs for the first N pages that it adds to cache. ^If additional 1525 ** page cache memory is needed beyond what is provided by this option, then 1526 ** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1527 ** The pointer in the first argument must 1528 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1529 ** will be undefined.</dd> 1530 ** 1531 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1532 ** <dd> ^This option specifies a static memory buffer that SQLite will use 1533 ** for all of its dynamic memory allocation needs beyond those provided 1534 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1535 ** There are three arguments: An 8-byte aligned pointer to the memory, 1536 ** the number of bytes in the memory buffer, and the minimum allocation size. 1537 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1538 ** to using its default memory allocator (the system malloc() implementation), 1539 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1540 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1541 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1542 ** allocator is engaged to handle all of SQLites memory allocation needs. 1543 ** The first pointer (the memory pointer) must be aligned to an 8-byte 1544 ** boundary or subsequent behavior of SQLite will be undefined. 1545 ** The minimum allocation size is capped at 2**12. Reasonable values 1546 ** for the minimum allocation size are 2**5 through 2**8.</dd> 1547 ** 1548 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1549 ** <dd> ^(This option takes a single argument which is a pointer to an 1550 ** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1551 ** alternative low-level mutex routines to be used in place 1552 ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1553 ** content of the [sqlite3_mutex_methods] structure before the call to 1554 ** [sqlite3_config()] returns. ^If SQLite is compiled with 1555 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1556 ** the entire mutexing subsystem is omitted from the build and hence calls to 1557 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1558 ** return [SQLITE_ERROR].</dd> 1559 ** 1560 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1561 ** <dd> ^(This option takes a single argument which is a pointer to an 1562 ** instance of the [sqlite3_mutex_methods] structure. The 1563 ** [sqlite3_mutex_methods] 1564 ** structure is filled with the currently defined mutex routines.)^ 1565 ** This option can be used to overload the default mutex allocation 1566 ** routines with a wrapper used to track mutex usage for performance 1567 ** profiling or testing, for example. ^If SQLite is compiled with 1568 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1569 ** the entire mutexing subsystem is omitted from the build and hence calls to 1570 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1571 ** return [SQLITE_ERROR].</dd> 1572 ** 1573 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1574 ** <dd> ^(This option takes two arguments that determine the default 1575 ** memory allocation for the lookaside memory allocator on each 1576 ** [database connection]. The first argument is the 1577 ** size of each lookaside buffer slot and the second is the number of 1578 ** slots allocated to each database connection.)^ ^(This option sets the 1579 ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1580 ** verb to [sqlite3_db_config()] can be used to change the lookaside 1581 ** configuration on individual connections.)^ </dd> 1582 ** 1583 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1584 ** <dd> ^(This option takes a single argument which is a pointer to 1585 ** an [sqlite3_pcache_methods2] object. This object specifies the interface 1586 ** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1587 ** object and uses it for page cache memory allocations.</dd> 1588 ** 1589 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1590 ** <dd> ^(This option takes a single argument which is a pointer to an 1591 ** [sqlite3_pcache_methods2] object. SQLite copies of the current 1592 ** page cache implementation into that object.)^ </dd> 1593 ** 1594 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1595 ** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1596 ** global [error log]. 1597 ** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1598 ** function with a call signature of void(*)(void*,int,const char*), 1599 ** and a pointer to void. ^If the function pointer is not NULL, it is 1600 ** invoked by [sqlite3_log()] to process each logging event. ^If the 1601 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1602 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1603 ** passed through as the first parameter to the application-defined logger 1604 ** function whenever that function is invoked. ^The second parameter to 1605 ** the logger function is a copy of the first parameter to the corresponding 1606 ** [sqlite3_log()] call and is intended to be a [result code] or an 1607 ** [extended result code]. ^The third parameter passed to the logger is 1608 ** log message after formatting via [sqlite3_snprintf()]. 1609 ** The SQLite logging interface is not reentrant; the logger function 1610 ** supplied by the application must not invoke any SQLite interface. 1611 ** In a multi-threaded application, the application-defined logger 1612 ** function must be threadsafe. </dd> 1613 ** 1614 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1615 ** <dd> This option takes a single argument of type int. If non-zero, then 1616 ** URI handling is globally enabled. If the parameter is zero, then URI handling 1617 ** is globally disabled. If URI handling is globally enabled, all filenames 1618 ** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or 1619 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1620 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1621 ** connection is opened. If it is globally disabled, filenames are 1622 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1623 ** database connection is opened. By default, URI handling is globally 1624 ** disabled. The default value may be changed by compiling with the 1625 ** [SQLITE_USE_URI] symbol defined. 1626 ** 1627 ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1628 ** <dd> This option takes a single integer argument which is interpreted as 1629 ** a boolean in order to enable or disable the use of covering indices for 1630 ** full table scans in the query optimizer. The default setting is determined 1631 ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1632 ** if that compile-time option is omitted. 1633 ** The ability to disable the use of covering indices for full table scans 1634 ** is because some incorrectly coded legacy applications might malfunction 1635 ** malfunction when the optimization is enabled. Providing the ability to 1636 ** disable the optimization allows the older, buggy application code to work 1637 ** without change even with newer versions of SQLite. 1638 ** 1639 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1640 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1641 ** <dd> These options are obsolete and should not be used by new code. 1642 ** They are retained for backwards compatibility but are now no-ops. 1643 ** </dd> 1644 ** 1645 ** [[SQLITE_CONFIG_SQLLOG]] 1646 ** <dt>SQLITE_CONFIG_SQLLOG 1647 ** <dd>This option is only available if sqlite is compiled with the 1648 ** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1649 ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1650 ** The second should be of type (void*). The callback is invoked by the library 1651 ** in three separate circumstances, identified by the value passed as the 1652 ** fourth parameter. If the fourth parameter is 0, then the database connection 1653 ** passed as the second argument has just been opened. The third argument 1654 ** points to a buffer containing the name of the main database file. If the 1655 ** fourth parameter is 1, then the SQL statement that the third parameter 1656 ** points to has just been executed. Or, if the fourth parameter is 2, then 1657 ** the connection being passed as the second parameter is being closed. The 1658 ** third parameter is passed NULL In this case. An example of using this 1659 ** configuration option can be seen in the "test_sqllog.c" source file in 1660 ** the canonical SQLite source tree.</dd> 1661 ** 1662 ** [[SQLITE_CONFIG_MMAP_SIZE]] 1663 ** <dt>SQLITE_CONFIG_MMAP_SIZE 1664 ** <dd>SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1665 ** that are the default mmap size limit (the default setting for 1666 ** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1667 ** The default setting can be overridden by each database connection using 1668 ** either the [PRAGMA mmap_size] command, or by using the 1669 ** [SQLITE_FCNTL_MMAP_SIZE] file control. The maximum allowed mmap size 1670 ** cannot be changed at run-time. Nor may the maximum allowed mmap size 1671 ** exceed the compile-time maximum mmap size set by the 1672 ** [SQLITE_MAX_MMAP_SIZE] compile-time option. 1673 ** If either argument to this option is negative, then that argument is 1674 ** changed to its compile-time default. 1675 ** </dl> 1676 */ 1677 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1678 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1679 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1680 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1681 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1682 #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1683 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1684 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1685 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1686 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1687 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1688 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1689 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1690 #define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1691 #define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1692 #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1693 #define SQLITE_CONFIG_URI 17 /* int */ 1694 #define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1695 #define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1696 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1697 #define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1698 #define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1699 1700 /* 1701 ** CAPI3REF: Database Connection Configuration Options 1702 ** 1703 ** These constants are the available integer configuration options that 1704 ** can be passed as the second argument to the [sqlite3_db_config()] interface. 1705 ** 1706 ** New configuration options may be added in future releases of SQLite. 1707 ** Existing configuration options might be discontinued. Applications 1708 ** should check the return code from [sqlite3_db_config()] to make sure that 1709 ** the call worked. ^The [sqlite3_db_config()] interface will return a 1710 ** non-zero [error code] if a discontinued or unsupported configuration option 1711 ** is invoked. 1712 ** 1713 ** <dl> 1714 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1715 ** <dd> ^This option takes three additional arguments that determine the 1716 ** [lookaside memory allocator] configuration for the [database connection]. 1717 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1718 ** pointer to a memory buffer to use for lookaside memory. 1719 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1720 ** may be NULL in which case SQLite will allocate the 1721 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1722 ** size of each lookaside buffer slot. ^The third argument is the number of 1723 ** slots. The size of the buffer in the first argument must be greater than 1724 ** or equal to the product of the second and third arguments. The buffer 1725 ** must be aligned to an 8-byte boundary. ^If the second argument to 1726 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1727 ** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1728 ** configuration for a database connection can only be changed when that 1729 ** connection is not currently using lookaside memory, or in other words 1730 ** when the "current value" returned by 1731 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1732 ** Any attempt to change the lookaside memory configuration when lookaside 1733 ** memory is in use leaves the configuration unchanged and returns 1734 ** [SQLITE_BUSY].)^</dd> 1735 ** 1736 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1737 ** <dd> ^This option is used to enable or disable the enforcement of 1738 ** [foreign key constraints]. There should be two additional arguments. 1739 ** The first argument is an integer which is 0 to disable FK enforcement, 1740 ** positive to enable FK enforcement or negative to leave FK enforcement 1741 ** unchanged. The second parameter is a pointer to an integer into which 1742 ** is written 0 or 1 to indicate whether FK enforcement is off or on 1743 ** following this call. The second parameter may be a NULL pointer, in 1744 ** which case the FK enforcement setting is not reported back. </dd> 1745 ** 1746 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1747 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1748 ** There should be two additional arguments. 1749 ** The first argument is an integer which is 0 to disable triggers, 1750 ** positive to enable triggers or negative to leave the setting unchanged. 1751 ** The second parameter is a pointer to an integer into which 1752 ** is written 0 or 1 to indicate whether triggers are disabled or enabled 1753 ** following this call. The second parameter may be a NULL pointer, in 1754 ** which case the trigger setting is not reported back. </dd> 1755 ** 1756 ** </dl> 1757 */ 1758 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1759 #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1760 #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1761 1762 1763 /* 1764 ** CAPI3REF: Enable Or Disable Extended Result Codes 1765 ** 1766 ** ^The sqlite3_extended_result_codes() routine enables or disables the 1767 ** [extended result codes] feature of SQLite. ^The extended result 1768 ** codes are disabled by default for historical compatibility. 1769 */ 1770 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff); 1771 1772 /* 1773 ** CAPI3REF: Last Insert Rowid 1774 ** 1775 ** ^Each entry in an SQLite table has a unique 64-bit signed 1776 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1777 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1778 ** names are not also used by explicitly declared columns. ^If 1779 ** the table has a column of type [INTEGER PRIMARY KEY] then that column 1780 ** is another alias for the rowid. 1781 ** 1782 ** ^This routine returns the [rowid] of the most recent 1783 ** successful [INSERT] into the database from the [database connection] 1784 ** in the first argument. ^As of SQLite version 3.7.7, this routines 1785 ** records the last insert rowid of both ordinary tables and [virtual tables]. 1786 ** ^If no successful [INSERT]s 1787 ** have ever occurred on that database connection, zero is returned. 1788 ** 1789 ** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1790 ** method, then this routine will return the [rowid] of the inserted 1791 ** row as long as the trigger or virtual table method is running. 1792 ** But once the trigger or virtual table method ends, the value returned 1793 ** by this routine reverts to what it was before the trigger or virtual 1794 ** table method began.)^ 1795 ** 1796 ** ^An [INSERT] that fails due to a constraint violation is not a 1797 ** successful [INSERT] and does not change the value returned by this 1798 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1799 ** and INSERT OR ABORT make no changes to the return value of this 1800 ** routine when their insertion fails. ^(When INSERT OR REPLACE 1801 ** encounters a constraint violation, it does not fail. The 1802 ** INSERT continues to completion after deleting rows that caused 1803 ** the constraint problem so INSERT OR REPLACE will always change 1804 ** the return value of this interface.)^ 1805 ** 1806 ** ^For the purposes of this routine, an [INSERT] is considered to 1807 ** be successful even if it is subsequently rolled back. 1808 ** 1809 ** This function is accessible to SQL statements via the 1810 ** [last_insert_rowid() SQL function]. 1811 ** 1812 ** If a separate thread performs a new [INSERT] on the same 1813 ** database connection while the [sqlite3_last_insert_rowid()] 1814 ** function is running and thus changes the last insert [rowid], 1815 ** then the value returned by [sqlite3_last_insert_rowid()] is 1816 ** unpredictable and might not equal either the old or the new 1817 ** last insert [rowid]. 1818 */ 1819 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1820 1821 /* 1822 ** CAPI3REF: Count The Number Of Rows Modified 1823 ** 1824 ** ^This function returns the number of database rows that were changed 1825 ** or inserted or deleted by the most recently completed SQL statement 1826 ** on the [database connection] specified by the first parameter. 1827 ** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1828 ** or [DELETE] statement are counted. Auxiliary changes caused by 1829 ** triggers or [foreign key actions] are not counted.)^ Use the 1830 ** [sqlite3_total_changes()] function to find the total number of changes 1831 ** including changes caused by triggers and foreign key actions. 1832 ** 1833 ** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1834 ** are not counted. Only real table changes are counted. 1835 ** 1836 ** ^(A "row change" is a change to a single row of a single table 1837 ** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1838 ** are changed as side effects of [REPLACE] constraint resolution, 1839 ** rollback, ABORT processing, [DROP TABLE], or by any other 1840 ** mechanisms do not count as direct row changes.)^ 1841 ** 1842 ** A "trigger context" is a scope of execution that begins and 1843 ** ends with the script of a [CREATE TRIGGER | trigger]. 1844 ** Most SQL statements are 1845 ** evaluated outside of any trigger. This is the "top level" 1846 ** trigger context. If a trigger fires from the top level, a 1847 ** new trigger context is entered for the duration of that one 1848 ** trigger. Subtriggers create subcontexts for their duration. 1849 ** 1850 ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1851 ** not create a new trigger context. 1852 ** 1853 ** ^This function returns the number of direct row changes in the 1854 ** most recent INSERT, UPDATE, or DELETE statement within the same 1855 ** trigger context. 1856 ** 1857 ** ^Thus, when called from the top level, this function returns the 1858 ** number of changes in the most recent INSERT, UPDATE, or DELETE 1859 ** that also occurred at the top level. ^(Within the body of a trigger, 1860 ** the sqlite3_changes() interface can be called to find the number of 1861 ** changes in the most recently completed INSERT, UPDATE, or DELETE 1862 ** statement within the body of the same trigger. 1863 ** However, the number returned does not include changes 1864 ** caused by subtriggers since those have their own context.)^ 1865 ** 1866 ** See also the [sqlite3_total_changes()] interface, the 1867 ** [count_changes pragma], and the [changes() SQL function]. 1868 ** 1869 ** If a separate thread makes changes on the same database connection 1870 ** while [sqlite3_changes()] is running then the value returned 1871 ** is unpredictable and not meaningful. 1872 */ 1873 SQLITE_API int sqlite3_changes(sqlite3*); 1874 1875 /* 1876 ** CAPI3REF: Total Number Of Rows Modified 1877 ** 1878 ** ^This function returns the number of row changes caused by [INSERT], 1879 ** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1880 ** ^(The count returned by sqlite3_total_changes() includes all changes 1881 ** from all [CREATE TRIGGER | trigger] contexts and changes made by 1882 ** [foreign key actions]. However, 1883 ** the count does not include changes used to implement [REPLACE] constraints, 1884 ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1885 ** count does not include rows of views that fire an [INSTEAD OF trigger], 1886 ** though if the INSTEAD OF trigger makes changes of its own, those changes 1887 ** are counted.)^ 1888 ** ^The sqlite3_total_changes() function counts the changes as soon as 1889 ** the statement that makes them is completed (when the statement handle 1890 ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1891 ** 1892 ** See also the [sqlite3_changes()] interface, the 1893 ** [count_changes pragma], and the [total_changes() SQL function]. 1894 ** 1895 ** If a separate thread makes changes on the same database connection 1896 ** while [sqlite3_total_changes()] is running then the value 1897 ** returned is unpredictable and not meaningful. 1898 */ 1899 SQLITE_API int sqlite3_total_changes(sqlite3*); 1900 1901 /* 1902 ** CAPI3REF: Interrupt A Long-Running Query 1903 ** 1904 ** ^This function causes any pending database operation to abort and 1905 ** return at its earliest opportunity. This routine is typically 1906 ** called in response to a user action such as pressing "Cancel" 1907 ** or Ctrl-C where the user wants a long query operation to halt 1908 ** immediately. 1909 ** 1910 ** ^It is safe to call this routine from a thread different from the 1911 ** thread that is currently running the database operation. But it 1912 ** is not safe to call this routine with a [database connection] that 1913 ** is closed or might close before sqlite3_interrupt() returns. 1914 ** 1915 ** ^If an SQL operation is very nearly finished at the time when 1916 ** sqlite3_interrupt() is called, then it might not have an opportunity 1917 ** to be interrupted and might continue to completion. 1918 ** 1919 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1920 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1921 ** that is inside an explicit transaction, then the entire transaction 1922 ** will be rolled back automatically. 1923 ** 1924 ** ^The sqlite3_interrupt(D) call is in effect until all currently running 1925 ** SQL statements on [database connection] D complete. ^Any new SQL statements 1926 ** that are started after the sqlite3_interrupt() call and before the 1927 ** running statements reaches zero are interrupted as if they had been 1928 ** running prior to the sqlite3_interrupt() call. ^New SQL statements 1929 ** that are started after the running statement count reaches zero are 1930 ** not effected by the sqlite3_interrupt(). 1931 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1932 ** SQL statements is a no-op and has no effect on SQL statements 1933 ** that are started after the sqlite3_interrupt() call returns. 1934 ** 1935 ** If the database connection closes while [sqlite3_interrupt()] 1936 ** is running then bad things will likely happen. 1937 */ 1938 SQLITE_API void sqlite3_interrupt(sqlite3*); 1939 1940 /* 1941 ** CAPI3REF: Determine If An SQL Statement Is Complete 1942 ** 1943 ** These routines are useful during command-line input to determine if the 1944 ** currently entered text seems to form a complete SQL statement or 1945 ** if additional input is needed before sending the text into 1946 ** SQLite for parsing. ^These routines return 1 if the input string 1947 ** appears to be a complete SQL statement. ^A statement is judged to be 1948 ** complete if it ends with a semicolon token and is not a prefix of a 1949 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1950 ** string literals or quoted identifier names or comments are not 1951 ** independent tokens (they are part of the token in which they are 1952 ** embedded) and thus do not count as a statement terminator. ^Whitespace 1953 ** and comments that follow the final semicolon are ignored. 1954 ** 1955 ** ^These routines return 0 if the statement is incomplete. ^If a 1956 ** memory allocation fails, then SQLITE_NOMEM is returned. 1957 ** 1958 ** ^These routines do not parse the SQL statements thus 1959 ** will not detect syntactically incorrect SQL. 1960 ** 1961 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1962 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1963 ** automatically by sqlite3_complete16(). If that initialization fails, 1964 ** then the return value from sqlite3_complete16() will be non-zero 1965 ** regardless of whether or not the input SQL is complete.)^ 1966 ** 1967 ** The input to [sqlite3_complete()] must be a zero-terminated 1968 ** UTF-8 string. 1969 ** 1970 ** The input to [sqlite3_complete16()] must be a zero-terminated 1971 ** UTF-16 string in native byte order. 1972 */ 1973 SQLITE_API int sqlite3_complete(const char *sql); 1974 SQLITE_API int sqlite3_complete16(const void *sql); 1975 1976 /* 1977 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1978 ** 1979 ** ^This routine sets a callback function that might be invoked whenever 1980 ** an attempt is made to open a database table that another thread 1981 ** or process has locked. 1982 ** 1983 ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1984 ** is returned immediately upon encountering the lock. ^If the busy callback 1985 ** is not NULL, then the callback might be invoked with two arguments. 1986 ** 1987 ** ^The first argument to the busy handler is a copy of the void* pointer which 1988 ** is the third argument to sqlite3_busy_handler(). ^The second argument to 1989 ** the busy handler callback is the number of times that the busy handler has 1990 ** been invoked for this locking event. ^If the 1991 ** busy callback returns 0, then no additional attempts are made to 1992 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1993 ** ^If the callback returns non-zero, then another attempt 1994 ** is made to open the database for reading and the cycle repeats. 1995 ** 1996 ** The presence of a busy handler does not guarantee that it will be invoked 1997 ** when there is lock contention. ^If SQLite determines that invoking the busy 1998 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1999 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 2000 ** Consider a scenario where one process is holding a read lock that 2001 ** it is trying to promote to a reserved lock and 2002 ** a second process is holding a reserved lock that it is trying 2003 ** to promote to an exclusive lock. The first process cannot proceed 2004 ** because it is blocked by the second and the second process cannot 2005 ** proceed because it is blocked by the first. If both processes 2006 ** invoke the busy handlers, neither will make any progress. Therefore, 2007 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2008 ** will induce the first process to release its read lock and allow 2009 ** the second process to proceed. 2010 ** 2011 ** ^The default busy callback is NULL. 2012 ** 2013 ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 2014 ** when SQLite is in the middle of a large transaction where all the 2015 ** changes will not fit into the in-memory cache. SQLite will 2016 ** already hold a RESERVED lock on the database file, but it needs 2017 ** to promote this lock to EXCLUSIVE so that it can spill cache 2018 ** pages into the database file without harm to concurrent 2019 ** readers. ^If it is unable to promote the lock, then the in-memory 2020 ** cache will be left in an inconsistent state and so the error 2021 ** code is promoted from the relatively benign [SQLITE_BUSY] to 2022 ** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 2023 ** forces an automatic rollback of the changes. See the 2024 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 2025 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why 2026 ** this is important. 2027 ** 2028 ** ^(There can only be a single busy handler defined for each 2029 ** [database connection]. Setting a new busy handler clears any 2030 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2031 ** will also set or clear the busy handler. 2032 ** 2033 ** The busy callback should not take any actions which modify the 2034 ** database connection that invoked the busy handler. Any such actions 2035 ** result in undefined behavior. 2036 ** 2037 ** A busy handler must not close the database connection 2038 ** or [prepared statement] that invoked the busy handler. 2039 */ 2040 SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 2041 2042 /* 2043 ** CAPI3REF: Set A Busy Timeout 2044 ** 2045 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2046 ** for a specified amount of time when a table is locked. ^The handler 2047 ** will sleep multiple times until at least "ms" milliseconds of sleeping 2048 ** have accumulated. ^After at least "ms" milliseconds of sleeping, 2049 ** the handler returns 0 which causes [sqlite3_step()] to return 2050 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 2051 ** 2052 ** ^Calling this routine with an argument less than or equal to zero 2053 ** turns off all busy handlers. 2054 ** 2055 ** ^(There can only be a single busy handler for a particular 2056 ** [database connection] any any given moment. If another busy handler 2057 ** was defined (using [sqlite3_busy_handler()]) prior to calling 2058 ** this routine, that other busy handler is cleared.)^ 2059 */ 2060 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms); 2061 2062 /* 2063 ** CAPI3REF: Convenience Routines For Running Queries 2064 ** 2065 ** This is a legacy interface that is preserved for backwards compatibility. 2066 ** Use of this interface is not recommended. 2067 ** 2068 ** Definition: A <b>result table</b> is memory data structure created by the 2069 ** [sqlite3_get_table()] interface. A result table records the 2070 ** complete query results from one or more queries. 2071 ** 2072 ** The table conceptually has a number of rows and columns. But 2073 ** these numbers are not part of the result table itself. These 2074 ** numbers are obtained separately. Let N be the number of rows 2075 ** and M be the number of columns. 2076 ** 2077 ** A result table is an array of pointers to zero-terminated UTF-8 strings. 2078 ** There are (N+1)*M elements in the array. The first M pointers point 2079 ** to zero-terminated strings that contain the names of the columns. 2080 ** The remaining entries all point to query results. NULL values result 2081 ** in NULL pointers. All other values are in their UTF-8 zero-terminated 2082 ** string representation as returned by [sqlite3_column_text()]. 2083 ** 2084 ** A result table might consist of one or more memory allocations. 2085 ** It is not safe to pass a result table directly to [sqlite3_free()]. 2086 ** A result table should be deallocated using [sqlite3_free_table()]. 2087 ** 2088 ** ^(As an example of the result table format, suppose a query result 2089 ** is as follows: 2090 ** 2091 ** <blockquote><pre> 2092 ** Name | Age 2093 ** ----------------------- 2094 ** Alice | 43 2095 ** Bob | 28 2096 ** Cindy | 21 2097 ** </pre></blockquote> 2098 ** 2099 ** There are two column (M==2) and three rows (N==3). Thus the 2100 ** result table has 8 entries. Suppose the result table is stored 2101 ** in an array names azResult. Then azResult holds this content: 2102 ** 2103 ** <blockquote><pre> 2104 ** azResult[0] = "Name"; 2105 ** azResult[1] = "Age"; 2106 ** azResult[2] = "Alice"; 2107 ** azResult[3] = "43"; 2108 ** azResult[4] = "Bob"; 2109 ** azResult[5] = "28"; 2110 ** azResult[6] = "Cindy"; 2111 ** azResult[7] = "21"; 2112 ** </pre></blockquote>)^ 2113 ** 2114 ** ^The sqlite3_get_table() function evaluates one or more 2115 ** semicolon-separated SQL statements in the zero-terminated UTF-8 2116 ** string of its 2nd parameter and returns a result table to the 2117 ** pointer given in its 3rd parameter. 2118 ** 2119 ** After the application has finished with the result from sqlite3_get_table(), 2120 ** it must pass the result table pointer to sqlite3_free_table() in order to 2121 ** release the memory that was malloced. Because of the way the 2122 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2123 ** function must not try to call [sqlite3_free()] directly. Only 2124 ** [sqlite3_free_table()] is able to release the memory properly and safely. 2125 ** 2126 ** The sqlite3_get_table() interface is implemented as a wrapper around 2127 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2128 ** to any internal data structures of SQLite. It uses only the public 2129 ** interface defined here. As a consequence, errors that occur in the 2130 ** wrapper layer outside of the internal [sqlite3_exec()] call are not 2131 ** reflected in subsequent calls to [sqlite3_errcode()] or 2132 ** [sqlite3_errmsg()]. 2133 */ 2134 SQLITE_API int sqlite3_get_table( 2135 sqlite3 *db, /* An open database */ 2136 const char *zSql, /* SQL to be evaluated */ 2137 char ***pazResult, /* Results of the query */ 2138 int *pnRow, /* Number of result rows written here */ 2139 int *pnColumn, /* Number of result columns written here */ 2140 char **pzErrmsg /* Error msg written here */ 2141 ); 2142 SQLITE_API void sqlite3_free_table(char **result); 2143 2144 /* 2145 ** CAPI3REF: Formatted String Printing Functions 2146 ** 2147 ** These routines are work-alikes of the "printf()" family of functions 2148 ** from the standard C library. 2149 ** 2150 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2151 ** results into memory obtained from [sqlite3_malloc()]. 2152 ** The strings returned by these two routines should be 2153 ** released by [sqlite3_free()]. ^Both routines return a 2154 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2155 ** memory to hold the resulting string. 2156 ** 2157 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2158 ** the standard C library. The result is written into the 2159 ** buffer supplied as the second parameter whose size is given by 2160 ** the first parameter. Note that the order of the 2161 ** first two parameters is reversed from snprintf().)^ This is an 2162 ** historical accident that cannot be fixed without breaking 2163 ** backwards compatibility. ^(Note also that sqlite3_snprintf() 2164 ** returns a pointer to its buffer instead of the number of 2165 ** characters actually written into the buffer.)^ We admit that 2166 ** the number of characters written would be a more useful return 2167 ** value but we cannot change the implementation of sqlite3_snprintf() 2168 ** now without breaking compatibility. 2169 ** 2170 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2171 ** guarantees that the buffer is always zero-terminated. ^The first 2172 ** parameter "n" is the total size of the buffer, including space for 2173 ** the zero terminator. So the longest string that can be completely 2174 ** written will be n-1 characters. 2175 ** 2176 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2177 ** 2178 ** These routines all implement some additional formatting 2179 ** options that are useful for constructing SQL statements. 2180 ** All of the usual printf() formatting options apply. In addition, there 2181 ** is are "%q", "%Q", and "%z" options. 2182 ** 2183 ** ^(The %q option works like %s in that it substitutes a nul-terminated 2184 ** string from the argument list. But %q also doubles every '\'' character. 2185 ** %q is designed for use inside a string literal.)^ By doubling each '\'' 2186 ** character it escapes that character and allows it to be inserted into 2187 ** the string. 2188 ** 2189 ** For example, assume the string variable zText contains text as follows: 2190 ** 2191 ** <blockquote><pre> 2192 ** char *zText = "It's a happy day!"; 2193 ** </pre></blockquote> 2194 ** 2195 ** One can use this text in an SQL statement as follows: 2196 ** 2197 ** <blockquote><pre> 2198 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2199 ** sqlite3_exec(db, zSQL, 0, 0, 0); 2200 ** sqlite3_free(zSQL); 2201 ** </pre></blockquote> 2202 ** 2203 ** Because the %q format string is used, the '\'' character in zText 2204 ** is escaped and the SQL generated is as follows: 2205 ** 2206 ** <blockquote><pre> 2207 ** INSERT INTO table1 VALUES('It''s a happy day!') 2208 ** </pre></blockquote> 2209 ** 2210 ** This is correct. Had we used %s instead of %q, the generated SQL 2211 ** would have looked like this: 2212 ** 2213 ** <blockquote><pre> 2214 ** INSERT INTO table1 VALUES('It's a happy day!'); 2215 ** </pre></blockquote> 2216 ** 2217 ** This second example is an SQL syntax error. As a general rule you should 2218 ** always use %q instead of %s when inserting text into a string literal. 2219 ** 2220 ** ^(The %Q option works like %q except it also adds single quotes around 2221 ** the outside of the total string. Additionally, if the parameter in the 2222 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2223 ** single quotes).)^ So, for example, one could say: 2224 ** 2225 ** <blockquote><pre> 2226 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2227 ** sqlite3_exec(db, zSQL, 0, 0, 0); 2228 ** sqlite3_free(zSQL); 2229 ** </pre></blockquote> 2230 ** 2231 ** The code above will render a correct SQL statement in the zSQL 2232 ** variable even if the zText variable is a NULL pointer. 2233 ** 2234 ** ^(The "%z" formatting option works like "%s" but with the 2235 ** addition that after the string has been read and copied into 2236 ** the result, [sqlite3_free()] is called on the input string.)^ 2237 */ 2238 SQLITE_API char *sqlite3_mprintf(const char*,...); 2239 SQLITE_API char *sqlite3_vmprintf(const char*, va_list); 2240 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...); 2241 SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2242 2243 /* 2244 ** CAPI3REF: Memory Allocation Subsystem 2245 ** 2246 ** The SQLite core uses these three routines for all of its own 2247 ** internal memory allocation needs. "Core" in the previous sentence 2248 ** does not include operating-system specific VFS implementation. The 2249 ** Windows VFS uses native malloc() and free() for some operations. 2250 ** 2251 ** ^The sqlite3_malloc() routine returns a pointer to a block 2252 ** of memory at least N bytes in length, where N is the parameter. 2253 ** ^If sqlite3_malloc() is unable to obtain sufficient free 2254 ** memory, it returns a NULL pointer. ^If the parameter N to 2255 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2256 ** a NULL pointer. 2257 ** 2258 ** ^Calling sqlite3_free() with a pointer previously returned 2259 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2260 ** that it might be reused. ^The sqlite3_free() routine is 2261 ** a no-op if is called with a NULL pointer. Passing a NULL pointer 2262 ** to sqlite3_free() is harmless. After being freed, memory 2263 ** should neither be read nor written. Even reading previously freed 2264 ** memory might result in a segmentation fault or other severe error. 2265 ** Memory corruption, a segmentation fault, or other severe error 2266 ** might result if sqlite3_free() is called with a non-NULL pointer that 2267 ** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2268 ** 2269 ** ^(The sqlite3_realloc() interface attempts to resize a 2270 ** prior memory allocation to be at least N bytes, where N is the 2271 ** second parameter. The memory allocation to be resized is the first 2272 ** parameter.)^ ^ If the first parameter to sqlite3_realloc() 2273 ** is a NULL pointer then its behavior is identical to calling 2274 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 2275 ** ^If the second parameter to sqlite3_realloc() is zero or 2276 ** negative then the behavior is exactly the same as calling 2277 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 2278 ** ^sqlite3_realloc() returns a pointer to a memory allocation 2279 ** of at least N bytes in size or NULL if sufficient memory is unavailable. 2280 ** ^If M is the size of the prior allocation, then min(N,M) bytes 2281 ** of the prior allocation are copied into the beginning of buffer returned 2282 ** by sqlite3_realloc() and the prior allocation is freed. 2283 ** ^If sqlite3_realloc() returns NULL, then the prior allocation 2284 ** is not freed. 2285 ** 2286 ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 2287 ** is always aligned to at least an 8 byte boundary, or to a 2288 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2289 ** option is used. 2290 ** 2291 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2292 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2293 ** implementation of these routines to be omitted. That capability 2294 ** is no longer provided. Only built-in memory allocators can be used. 2295 ** 2296 ** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2297 ** the system malloc() and free() directly when converting 2298 ** filenames between the UTF-8 encoding used by SQLite 2299 ** and whatever filename encoding is used by the particular Windows 2300 ** installation. Memory allocation errors were detected, but 2301 ** they were reported back as [SQLITE_CANTOPEN] or 2302 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2303 ** 2304 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2305 ** must be either NULL or else pointers obtained from a prior 2306 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2307 ** not yet been released. 2308 ** 2309 ** The application must not read or write any part of 2310 ** a block of memory after it has been released using 2311 ** [sqlite3_free()] or [sqlite3_realloc()]. 2312 */ 2313 SQLITE_API void *sqlite3_malloc(int); 2314 SQLITE_API void *sqlite3_realloc(void*, int); 2315 SQLITE_API void sqlite3_free(void*); 2316 2317 /* 2318 ** CAPI3REF: Memory Allocator Statistics 2319 ** 2320 ** SQLite provides these two interfaces for reporting on the status 2321 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2322 ** routines, which form the built-in memory allocation subsystem. 2323 ** 2324 ** ^The [sqlite3_memory_used()] routine returns the number of bytes 2325 ** of memory currently outstanding (malloced but not freed). 2326 ** ^The [sqlite3_memory_highwater()] routine returns the maximum 2327 ** value of [sqlite3_memory_used()] since the high-water mark 2328 ** was last reset. ^The values returned by [sqlite3_memory_used()] and 2329 ** [sqlite3_memory_highwater()] include any overhead 2330 ** added by SQLite in its implementation of [sqlite3_malloc()], 2331 ** but not overhead added by the any underlying system library 2332 ** routines that [sqlite3_malloc()] may call. 2333 ** 2334 ** ^The memory high-water mark is reset to the current value of 2335 ** [sqlite3_memory_used()] if and only if the parameter to 2336 ** [sqlite3_memory_highwater()] is true. ^The value returned 2337 ** by [sqlite3_memory_highwater(1)] is the high-water mark 2338 ** prior to the reset. 2339 */ 2340 SQLITE_API sqlite3_int64 sqlite3_memory_used(void); 2341 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2342 2343 /* 2344 ** CAPI3REF: Pseudo-Random Number Generator 2345 ** 2346 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2347 ** select random [ROWID | ROWIDs] when inserting new records into a table that 2348 ** already uses the largest possible [ROWID]. The PRNG is also used for 2349 ** the build-in random() and randomblob() SQL functions. This interface allows 2350 ** applications to access the same PRNG for other purposes. 2351 ** 2352 ** ^A call to this routine stores N bytes of randomness into buffer P. 2353 ** 2354 ** ^The first time this routine is invoked (either internally or by 2355 ** the application) the PRNG is seeded using randomness obtained 2356 ** from the xRandomness method of the default [sqlite3_vfs] object. 2357 ** ^On all subsequent invocations, the pseudo-randomness is generated 2358 ** internally and without recourse to the [sqlite3_vfs] xRandomness 2359 ** method. 2360 */ 2361 SQLITE_API void sqlite3_randomness(int N, void *P); 2362 2363 /* 2364 ** CAPI3REF: Compile-Time Authorization Callbacks 2365 ** 2366 ** ^This routine registers an authorizer callback with a particular 2367 ** [database connection], supplied in the first argument. 2368 ** ^The authorizer callback is invoked as SQL statements are being compiled 2369 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2370 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2371 ** points during the compilation process, as logic is being created 2372 ** to perform various actions, the authorizer callback is invoked to 2373 ** see if those actions are allowed. ^The authorizer callback should 2374 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2375 ** specific action but allow the SQL statement to continue to be 2376 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2377 ** rejected with an error. ^If the authorizer callback returns 2378 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2379 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2380 ** the authorizer will fail with an error message. 2381 ** 2382 ** When the callback returns [SQLITE_OK], that means the operation 2383 ** requested is ok. ^When the callback returns [SQLITE_DENY], the 2384 ** [sqlite3_prepare_v2()] or equivalent call that triggered the 2385 ** authorizer will fail with an error message explaining that 2386 ** access is denied. 2387 ** 2388 ** ^The first parameter to the authorizer callback is a copy of the third 2389 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2390 ** to the callback is an integer [SQLITE_COPY | action code] that specifies 2391 ** the particular action to be authorized. ^The third through sixth parameters 2392 ** to the callback are zero-terminated strings that contain additional 2393 ** details about the action to be authorized. 2394 ** 2395 ** ^If the action code is [SQLITE_READ] 2396 ** and the callback returns [SQLITE_IGNORE] then the 2397 ** [prepared statement] statement is constructed to substitute 2398 ** a NULL value in place of the table column that would have 2399 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2400 ** return can be used to deny an untrusted user access to individual 2401 ** columns of a table. 2402 ** ^If the action code is [SQLITE_DELETE] and the callback returns 2403 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2404 ** [truncate optimization] is disabled and all rows are deleted individually. 2405 ** 2406 ** An authorizer is used when [sqlite3_prepare | preparing] 2407 ** SQL statements from an untrusted source, to ensure that the SQL statements 2408 ** do not try to access data they are not allowed to see, or that they do not 2409 ** try to execute malicious statements that damage the database. For 2410 ** example, an application may allow a user to enter arbitrary 2411 ** SQL queries for evaluation by a database. But the application does 2412 ** not want the user to be able to make arbitrary changes to the 2413 ** database. An authorizer could then be put in place while the 2414 ** user-entered SQL is being [sqlite3_prepare | prepared] that 2415 ** disallows everything except [SELECT] statements. 2416 ** 2417 ** Applications that need to process SQL from untrusted sources 2418 ** might also consider lowering resource limits using [sqlite3_limit()] 2419 ** and limiting database size using the [max_page_count] [PRAGMA] 2420 ** in addition to using an authorizer. 2421 ** 2422 ** ^(Only a single authorizer can be in place on a database connection 2423 ** at a time. Each call to sqlite3_set_authorizer overrides the 2424 ** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2425 ** The authorizer is disabled by default. 2426 ** 2427 ** The authorizer callback must not do anything that will modify 2428 ** the database connection that invoked the authorizer callback. 2429 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2430 ** database connections for the meaning of "modify" in this paragraph. 2431 ** 2432 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2433 ** statement might be re-prepared during [sqlite3_step()] due to a 2434 ** schema change. Hence, the application should ensure that the 2435 ** correct authorizer callback remains in place during the [sqlite3_step()]. 2436 ** 2437 ** ^Note that the authorizer callback is invoked only during 2438 ** [sqlite3_prepare()] or its variants. Authorization is not 2439 ** performed during statement evaluation in [sqlite3_step()], unless 2440 ** as stated in the previous paragraph, sqlite3_step() invokes 2441 ** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2442 */ 2443 SQLITE_API int sqlite3_set_authorizer( 2444 sqlite3*, 2445 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2446 void *pUserData 2447 ); 2448 2449 /* 2450 ** CAPI3REF: Authorizer Return Codes 2451 ** 2452 ** The [sqlite3_set_authorizer | authorizer callback function] must 2453 ** return either [SQLITE_OK] or one of these two constants in order 2454 ** to signal SQLite whether or not the action is permitted. See the 2455 ** [sqlite3_set_authorizer | authorizer documentation] for additional 2456 ** information. 2457 ** 2458 ** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code] 2459 ** from the [sqlite3_vtab_on_conflict()] interface. 2460 */ 2461 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2462 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2463 2464 /* 2465 ** CAPI3REF: Authorizer Action Codes 2466 ** 2467 ** The [sqlite3_set_authorizer()] interface registers a callback function 2468 ** that is invoked to authorize certain SQL statement actions. The 2469 ** second parameter to the callback is an integer code that specifies 2470 ** what action is being authorized. These are the integer action codes that 2471 ** the authorizer callback may be passed. 2472 ** 2473 ** These action code values signify what kind of operation is to be 2474 ** authorized. The 3rd and 4th parameters to the authorization 2475 ** callback function will be parameters or NULL depending on which of these 2476 ** codes is used as the second parameter. ^(The 5th parameter to the 2477 ** authorizer callback is the name of the database ("main", "temp", 2478 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2479 ** is the name of the inner-most trigger or view that is responsible for 2480 ** the access attempt or NULL if this access attempt is directly from 2481 ** top-level SQL code. 2482 */ 2483 /******************************************* 3rd ************ 4th ***********/ 2484 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2485 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2486 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2487 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2488 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2489 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2490 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2491 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2492 #define SQLITE_DELETE 9 /* Table Name NULL */ 2493 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2494 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2495 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2496 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2497 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2498 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2499 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2500 #define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2501 #define SQLITE_INSERT 18 /* Table Name NULL */ 2502 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2503 #define SQLITE_READ 20 /* Table Name Column Name */ 2504 #define SQLITE_SELECT 21 /* NULL NULL */ 2505 #define SQLITE_TRANSACTION 22 /* Operation NULL */ 2506 #define SQLITE_UPDATE 23 /* Table Name Column Name */ 2507 #define SQLITE_ATTACH 24 /* Filename NULL */ 2508 #define SQLITE_DETACH 25 /* Database Name NULL */ 2509 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2510 #define SQLITE_REINDEX 27 /* Index Name NULL */ 2511 #define SQLITE_ANALYZE 28 /* Table Name NULL */ 2512 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2513 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2514 #define SQLITE_FUNCTION 31 /* NULL Function Name */ 2515 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2516 #define SQLITE_COPY 0 /* No longer used */ 2517 2518 /* 2519 ** CAPI3REF: Tracing And Profiling Functions 2520 ** 2521 ** These routines register callback functions that can be used for 2522 ** tracing and profiling the execution of SQL statements. 2523 ** 2524 ** ^The callback function registered by sqlite3_trace() is invoked at 2525 ** various times when an SQL statement is being run by [sqlite3_step()]. 2526 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2527 ** SQL statement text as the statement first begins executing. 2528 ** ^(Additional sqlite3_trace() callbacks might occur 2529 ** as each triggered subprogram is entered. The callbacks for triggers 2530 ** contain a UTF-8 SQL comment that identifies the trigger.)^ 2531 ** 2532 ** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2533 ** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2534 ** 2535 ** ^The callback function registered by sqlite3_profile() is invoked 2536 ** as each SQL statement finishes. ^The profile callback contains 2537 ** the original statement text and an estimate of wall-clock time 2538 ** of how long that statement took to run. ^The profile callback 2539 ** time is in units of nanoseconds, however the current implementation 2540 ** is only capable of millisecond resolution so the six least significant 2541 ** digits in the time are meaningless. Future versions of SQLite 2542 ** might provide greater resolution on the profiler callback. The 2543 ** sqlite3_profile() function is considered experimental and is 2544 ** subject to change in future versions of SQLite. 2545 */ 2546 SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2547 SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2548 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2549 2550 /* 2551 ** CAPI3REF: Query Progress Callbacks 2552 ** 2553 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2554 ** function X to be invoked periodically during long running calls to 2555 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2556 ** database connection D. An example use for this 2557 ** interface is to keep a GUI updated during a large query. 2558 ** 2559 ** ^The parameter P is passed through as the only parameter to the 2560 ** callback function X. ^The parameter N is the number of 2561 ** [virtual machine instructions] that are evaluated between successive 2562 ** invocations of the callback X. 2563 ** 2564 ** ^Only a single progress handler may be defined at one time per 2565 ** [database connection]; setting a new progress handler cancels the 2566 ** old one. ^Setting parameter X to NULL disables the progress handler. 2567 ** ^The progress handler is also disabled by setting N to a value less 2568 ** than 1. 2569 ** 2570 ** ^If the progress callback returns non-zero, the operation is 2571 ** interrupted. This feature can be used to implement a 2572 ** "Cancel" button on a GUI progress dialog box. 2573 ** 2574 ** The progress handler callback must not do anything that will modify 2575 ** the database connection that invoked the progress handler. 2576 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2577 ** database connections for the meaning of "modify" in this paragraph. 2578 ** 2579 */ 2580 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2581 2582 /* 2583 ** CAPI3REF: Opening A New Database Connection 2584 ** 2585 ** ^These routines open an SQLite database file as specified by the 2586 ** filename argument. ^The filename argument is interpreted as UTF-8 for 2587 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2588 ** order for sqlite3_open16(). ^(A [database connection] handle is usually 2589 ** returned in *ppDb, even if an error occurs. The only exception is that 2590 ** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2591 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2592 ** object.)^ ^(If the database is opened (and/or created) successfully, then 2593 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2594 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2595 ** an English language description of the error following a failure of any 2596 ** of the sqlite3_open() routines. 2597 ** 2598 ** ^The default encoding for the database will be UTF-8 if 2599 ** sqlite3_open() or sqlite3_open_v2() is called and 2600 ** UTF-16 in the native byte order if sqlite3_open16() is used. 2601 ** 2602 ** Whether or not an error occurs when it is opened, resources 2603 ** associated with the [database connection] handle should be released by 2604 ** passing it to [sqlite3_close()] when it is no longer required. 2605 ** 2606 ** The sqlite3_open_v2() interface works like sqlite3_open() 2607 ** except that it accepts two additional parameters for additional control 2608 ** over the new database connection. ^(The flags parameter to 2609 ** sqlite3_open_v2() can take one of 2610 ** the following three values, optionally combined with the 2611 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2612 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2613 ** 2614 ** <dl> 2615 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2616 ** <dd>The database is opened in read-only mode. If the database does not 2617 ** already exist, an error is returned.</dd>)^ 2618 ** 2619 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2620 ** <dd>The database is opened for reading and writing if possible, or reading 2621 ** only if the file is write protected by the operating system. In either 2622 ** case the database must already exist, otherwise an error is returned.</dd>)^ 2623 ** 2624 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2625 ** <dd>The database is opened for reading and writing, and is created if 2626 ** it does not already exist. This is the behavior that is always used for 2627 ** sqlite3_open() and sqlite3_open16().</dd>)^ 2628 ** </dl> 2629 ** 2630 ** If the 3rd parameter to sqlite3_open_v2() is not one of the 2631 ** combinations shown above optionally combined with other 2632 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2633 ** then the behavior is undefined. 2634 ** 2635 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2636 ** opens in the multi-thread [threading mode] as long as the single-thread 2637 ** mode has not been set at compile-time or start-time. ^If the 2638 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2639 ** in the serialized [threading mode] unless single-thread was 2640 ** previously selected at compile-time or start-time. 2641 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2642 ** eligible to use [shared cache mode], regardless of whether or not shared 2643 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2644 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2645 ** participate in [shared cache mode] even if it is enabled. 2646 ** 2647 ** ^The fourth parameter to sqlite3_open_v2() is the name of the 2648 ** [sqlite3_vfs] object that defines the operating system interface that 2649 ** the new database connection should use. ^If the fourth parameter is 2650 ** a NULL pointer then the default [sqlite3_vfs] object is used. 2651 ** 2652 ** ^If the filename is ":memory:", then a private, temporary in-memory database 2653 ** is created for the connection. ^This in-memory database will vanish when 2654 ** the database connection is closed. Future versions of SQLite might 2655 ** make use of additional special filenames that begin with the ":" character. 2656 ** It is recommended that when a database filename actually does begin with 2657 ** a ":" character you should prefix the filename with a pathname such as 2658 ** "./" to avoid ambiguity. 2659 ** 2660 ** ^If the filename is an empty string, then a private, temporary 2661 ** on-disk database will be created. ^This private database will be 2662 ** automatically deleted as soon as the database connection is closed. 2663 ** 2664 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2665 ** 2666 ** ^If [URI filename] interpretation is enabled, and the filename argument 2667 ** begins with "file:", then the filename is interpreted as a URI. ^URI 2668 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2669 ** set in the fourth argument to sqlite3_open_v2(), or if it has 2670 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2671 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2672 ** As of SQLite version 3.7.7, URI filename interpretation is turned off 2673 ** by default, but future releases of SQLite might enable URI filename 2674 ** interpretation by default. See "[URI filenames]" for additional 2675 ** information. 2676 ** 2677 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2678 ** authority, then it must be either an empty string or the string 2679 ** "localhost". ^If the authority is not an empty string or "localhost", an 2680 ** error is returned to the caller. ^The fragment component of a URI, if 2681 ** present, is ignored. 2682 ** 2683 ** ^SQLite uses the path component of the URI as the name of the disk file 2684 ** which contains the database. ^If the path begins with a '/' character, 2685 ** then it is interpreted as an absolute path. ^If the path does not begin 2686 ** with a '/' (meaning that the authority section is omitted from the URI) 2687 ** then the path is interpreted as a relative path. 2688 ** ^On windows, the first component of an absolute path 2689 ** is a drive specification (e.g. "C:"). 2690 ** 2691 ** [[core URI query parameters]] 2692 ** The query component of a URI may contain parameters that are interpreted 2693 ** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2694 ** SQLite interprets the following three query parameters: 2695 ** 2696 ** <ul> 2697 ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2698 ** a VFS object that provides the operating system interface that should 2699 ** be used to access the database file on disk. ^If this option is set to 2700 ** an empty string the default VFS object is used. ^Specifying an unknown 2701 ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2702 ** present, then the VFS specified by the option takes precedence over 2703 ** the value passed as the fourth parameter to sqlite3_open_v2(). 2704 ** 2705 ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 2706 ** "rwc", or "memory". Attempting to set it to any other value is 2707 ** an error)^. 2708 ** ^If "ro" is specified, then the database is opened for read-only 2709 ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2710 ** third argument to sqlite3_open_v2(). ^If the mode option is set to 2711 ** "rw", then the database is opened for read-write (but not create) 2712 ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2713 ** been set. ^Value "rwc" is equivalent to setting both 2714 ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 2715 ** set to "memory" then a pure [in-memory database] that never reads 2716 ** or writes from disk is used. ^It is an error to specify a value for 2717 ** the mode parameter that is less restrictive than that specified by 2718 ** the flags passed in the third parameter to sqlite3_open_v2(). 2719 ** 2720 ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2721 ** "private". ^Setting it to "shared" is equivalent to setting the 2722 ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2723 ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2724 ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2725 ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2726 ** a URI filename, its value overrides any behavior requested by setting 2727 ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2728 ** </ul> 2729 ** 2730 ** ^Specifying an unknown parameter in the query component of a URI is not an 2731 ** error. Future versions of SQLite might understand additional query 2732 ** parameters. See "[query parameters with special meaning to SQLite]" for 2733 ** additional information. 2734 ** 2735 ** [[URI filename examples]] <h3>URI filename examples</h3> 2736 ** 2737 ** <table border="1" align=center cellpadding=5> 2738 ** <tr><th> URI filenames <th> Results 2739 ** <tr><td> file:data.db <td> 2740 ** Open the file "data.db" in the current directory. 2741 ** <tr><td> file:/home/fred/data.db<br> 2742 ** file:///home/fred/data.db <br> 2743 ** file://localhost/home/fred/data.db <br> <td> 2744 ** Open the database file "/home/fred/data.db". 2745 ** <tr><td> file://darkstar/home/fred/data.db <td> 2746 ** An error. "darkstar" is not a recognized authority. 2747 ** <tr><td style="white-space:nowrap"> 2748 ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2749 ** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2750 ** C:. Note that the %20 escaping in this example is not strictly 2751 ** necessary - space characters can be used literally 2752 ** in URI filenames. 2753 ** <tr><td> file:data.db?mode=ro&cache=private <td> 2754 ** Open file "data.db" in the current directory for read-only access. 2755 ** Regardless of whether or not shared-cache mode is enabled by 2756 ** default, use a private cache. 2757 ** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td> 2758 ** Open file "/home/fred/data.db". Use the special VFS "unix-nolock". 2759 ** <tr><td> file:data.db?mode=readonly <td> 2760 ** An error. "readonly" is not a valid option for the "mode" parameter. 2761 ** </table> 2762 ** 2763 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2764 ** query components of a URI. A hexadecimal escape sequence consists of a 2765 ** percent sign - "%" - followed by exactly two hexadecimal digits 2766 ** specifying an octet value. ^Before the path or query components of a 2767 ** URI filename are interpreted, they are encoded using UTF-8 and all 2768 ** hexadecimal escape sequences replaced by a single byte containing the 2769 ** corresponding octet. If this process generates an invalid UTF-8 encoding, 2770 ** the results are undefined. 2771 ** 2772 ** <b>Note to Windows users:</b> The encoding used for the filename argument 2773 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2774 ** codepage is currently defined. Filenames containing international 2775 ** characters must be converted to UTF-8 prior to passing them into 2776 ** sqlite3_open() or sqlite3_open_v2(). 2777 ** 2778 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set 2779 ** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 2780 ** features that require the use of temporary files may fail. 2781 ** 2782 ** See also: [sqlite3_temp_directory] 2783 */ 2784 SQLITE_API int sqlite3_open( 2785 const char *filename, /* Database filename (UTF-8) */ 2786 sqlite3 **ppDb /* OUT: SQLite db handle */ 2787 ); 2788 SQLITE_API int sqlite3_open16( 2789 const void *filename, /* Database filename (UTF-16) */ 2790 sqlite3 **ppDb /* OUT: SQLite db handle */ 2791 ); 2792 SQLITE_API int sqlite3_open_v2( 2793 const char *filename, /* Database filename (UTF-8) */ 2794 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2795 int flags, /* Flags */ 2796 const char *zVfs /* Name of VFS module to use */ 2797 ); 2798 2799 /* 2800 ** CAPI3REF: Obtain Values For URI Parameters 2801 ** 2802 ** These are utility routines, useful to VFS implementations, that check 2803 ** to see if a database file was a URI that contained a specific query 2804 ** parameter, and if so obtains the value of that query parameter. 2805 ** 2806 ** If F is the database filename pointer passed into the xOpen() method of 2807 ** a VFS implementation when the flags parameter to xOpen() has one or 2808 ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 2809 ** P is the name of the query parameter, then 2810 ** sqlite3_uri_parameter(F,P) returns the value of the P 2811 ** parameter if it exists or a NULL pointer if P does not appear as a 2812 ** query parameter on F. If P is a query parameter of F 2813 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns 2814 ** a pointer to an empty string. 2815 ** 2816 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 2817 ** parameter and returns true (1) or false (0) according to the value 2818 ** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 2819 ** value of query parameter P is one of "yes", "true", or "on" in any 2820 ** case or if the value begins with a non-zero number. The 2821 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 2822 ** query parameter P is one of "no", "false", or "off" in any case or 2823 ** if the value begins with a numeric zero. If P is not a query 2824 ** parameter on F or if the value of P is does not match any of the 2825 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 2826 ** 2827 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 2828 ** 64-bit signed integer and returns that integer, or D if P does not 2829 ** exist. If the value of P is something other than an integer, then 2830 ** zero is returned. 2831 ** 2832 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 2833 ** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 2834 ** is not a database file pathname pointer that SQLite passed into the xOpen 2835 ** VFS method, then the behavior of this routine is undefined and probably 2836 ** undesirable. 2837 */ 2838 SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 2839 SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 2840 SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 2841 2842 2843 /* 2844 ** CAPI3REF: Error Codes And Messages 2845 ** 2846 ** ^The sqlite3_errcode() interface returns the numeric [result code] or 2847 ** [extended result code] for the most recent failed sqlite3_* API call 2848 ** associated with a [database connection]. If a prior API call failed 2849 ** but the most recent API call succeeded, the return value from 2850 ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2851 ** interface is the same except that it always returns the 2852 ** [extended result code] even when extended result codes are 2853 ** disabled. 2854 ** 2855 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2856 ** text that describes the error, as either UTF-8 or UTF-16 respectively. 2857 ** ^(Memory to hold the error message string is managed internally. 2858 ** The application does not need to worry about freeing the result. 2859 ** However, the error string might be overwritten or deallocated by 2860 ** subsequent calls to other SQLite interface functions.)^ 2861 ** 2862 ** ^The sqlite3_errstr() interface returns the English-language text 2863 ** that describes the [result code], as UTF-8. 2864 ** ^(Memory to hold the error message string is managed internally 2865 ** and must not be freed by the application)^. 2866 ** 2867 ** When the serialized [threading mode] is in use, it might be the 2868 ** case that a second error occurs on a separate thread in between 2869 ** the time of the first error and the call to these interfaces. 2870 ** When that happens, the second error will be reported since these 2871 ** interfaces always report the most recent result. To avoid 2872 ** this, each thread can obtain exclusive use of the [database connection] D 2873 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2874 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2875 ** all calls to the interfaces listed here are completed. 2876 ** 2877 ** If an interface fails with SQLITE_MISUSE, that means the interface 2878 ** was invoked incorrectly by the application. In that case, the 2879 ** error code and message may or may not be set. 2880 */ 2881 SQLITE_API int sqlite3_errcode(sqlite3 *db); 2882 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db); 2883 SQLITE_API const char *sqlite3_errmsg(sqlite3*); 2884 SQLITE_API const void *sqlite3_errmsg16(sqlite3*); 2885 SQLITE_API const char *sqlite3_errstr(int); 2886 2887 /* 2888 ** CAPI3REF: SQL Statement Object 2889 ** KEYWORDS: {prepared statement} {prepared statements} 2890 ** 2891 ** An instance of this object represents a single SQL statement. 2892 ** This object is variously known as a "prepared statement" or a 2893 ** "compiled SQL statement" or simply as a "statement". 2894 ** 2895 ** The life of a statement object goes something like this: 2896 ** 2897 ** <ol> 2898 ** <li> Create the object using [sqlite3_prepare_v2()] or a related 2899 ** function. 2900 ** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2901 ** interfaces. 2902 ** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2903 ** <li> Reset the statement using [sqlite3_reset()] then go back 2904 ** to step 2. Do this zero or more times. 2905 ** <li> Destroy the object using [sqlite3_finalize()]. 2906 ** </ol> 2907 ** 2908 ** Refer to documentation on individual methods above for additional 2909 ** information. 2910 */ 2911 typedef struct sqlite3_stmt sqlite3_stmt; 2912 2913 /* 2914 ** CAPI3REF: Run-time Limits 2915 ** 2916 ** ^(This interface allows the size of various constructs to be limited 2917 ** on a connection by connection basis. The first parameter is the 2918 ** [database connection] whose limit is to be set or queried. The 2919 ** second parameter is one of the [limit categories] that define a 2920 ** class of constructs to be size limited. The third parameter is the 2921 ** new limit for that construct.)^ 2922 ** 2923 ** ^If the new limit is a negative number, the limit is unchanged. 2924 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 2925 ** [limits | hard upper bound] 2926 ** set at compile-time by a C preprocessor macro called 2927 ** [limits | SQLITE_MAX_<i>NAME</i>]. 2928 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2929 ** ^Attempts to increase a limit above its hard upper bound are 2930 ** silently truncated to the hard upper bound. 2931 ** 2932 ** ^Regardless of whether or not the limit was changed, the 2933 ** [sqlite3_limit()] interface returns the prior value of the limit. 2934 ** ^Hence, to find the current value of a limit without changing it, 2935 ** simply invoke this interface with the third parameter set to -1. 2936 ** 2937 ** Run-time limits are intended for use in applications that manage 2938 ** both their own internal database and also databases that are controlled 2939 ** by untrusted external sources. An example application might be a 2940 ** web browser that has its own databases for storing history and 2941 ** separate databases controlled by JavaScript applications downloaded 2942 ** off the Internet. The internal databases can be given the 2943 ** large, default limits. Databases managed by external sources can 2944 ** be given much smaller limits designed to prevent a denial of service 2945 ** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2946 ** interface to further control untrusted SQL. The size of the database 2947 ** created by an untrusted script can be contained using the 2948 ** [max_page_count] [PRAGMA]. 2949 ** 2950 ** New run-time limit categories may be added in future releases. 2951 */ 2952 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal); 2953 2954 /* 2955 ** CAPI3REF: Run-Time Limit Categories 2956 ** KEYWORDS: {limit category} {*limit categories} 2957 ** 2958 ** These constants define various performance limits 2959 ** that can be lowered at run-time using [sqlite3_limit()]. 2960 ** The synopsis of the meanings of the various limits is shown below. 2961 ** Additional information is available at [limits | Limits in SQLite]. 2962 ** 2963 ** <dl> 2964 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2965 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 2966 ** 2967 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2968 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2969 ** 2970 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2971 ** <dd>The maximum number of columns in a table definition or in the 2972 ** result set of a [SELECT] or the maximum number of columns in an index 2973 ** or in an ORDER BY or GROUP BY clause.</dd>)^ 2974 ** 2975 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2976 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2977 ** 2978 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2979 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2980 ** 2981 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2982 ** <dd>The maximum number of instructions in a virtual machine program 2983 ** used to implement an SQL statement. This limit is not currently 2984 ** enforced, though that might be added in some future release of 2985 ** SQLite.</dd>)^ 2986 ** 2987 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2988 ** <dd>The maximum number of arguments on a function.</dd>)^ 2989 ** 2990 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2991 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2992 ** 2993 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 2994 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2995 ** <dd>The maximum length of the pattern argument to the [LIKE] or 2996 ** [GLOB] operators.</dd>)^ 2997 ** 2998 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 2999 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3000 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3001 ** 3002 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3003 ** <dd>The maximum depth of recursion for triggers.</dd>)^ 3004 ** </dl> 3005 */ 3006 #define SQLITE_LIMIT_LENGTH 0 3007 #define SQLITE_LIMIT_SQL_LENGTH 1 3008 #define SQLITE_LIMIT_COLUMN 2 3009 #define SQLITE_LIMIT_EXPR_DEPTH 3 3010 #define SQLITE_LIMIT_COMPOUND_SELECT 4 3011 #define SQLITE_LIMIT_VDBE_OP 5 3012 #define SQLITE_LIMIT_FUNCTION_ARG 6 3013 #define SQLITE_LIMIT_ATTACHED 7 3014 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3015 #define SQLITE_LIMIT_VARIABLE_NUMBER 9 3016 #define SQLITE_LIMIT_TRIGGER_DEPTH 10 3017 3018 /* 3019 ** CAPI3REF: Compiling An SQL Statement 3020 ** KEYWORDS: {SQL statement compiler} 3021 ** 3022 ** To execute an SQL query, it must first be compiled into a byte-code 3023 ** program using one of these routines. 3024 ** 3025 ** The first argument, "db", is a [database connection] obtained from a 3026 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3027 ** [sqlite3_open16()]. The database connection must not have been closed. 3028 ** 3029 ** The second argument, "zSql", is the statement to be compiled, encoded 3030 ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 3031 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 3032 ** use UTF-16. 3033 ** 3034 ** ^If the nByte argument is less than zero, then zSql is read up to the 3035 ** first zero terminator. ^If nByte is non-negative, then it is the maximum 3036 ** number of bytes read from zSql. ^When nByte is non-negative, the 3037 ** zSql string ends at either the first '\000' or '\u0000' character or 3038 ** the nByte-th byte, whichever comes first. If the caller knows 3039 ** that the supplied string is nul-terminated, then there is a small 3040 ** performance advantage to be gained by passing an nByte parameter that 3041 ** is equal to the number of bytes in the input string <i>including</i> 3042 ** the nul-terminator bytes as this saves SQLite from having to 3043 ** make a copy of the input string. 3044 ** 3045 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3046 ** past the end of the first SQL statement in zSql. These routines only 3047 ** compile the first statement in zSql, so *pzTail is left pointing to 3048 ** what remains uncompiled. 3049 ** 3050 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3051 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3052 ** to NULL. ^If the input text contains no SQL (if the input is an empty 3053 ** string or a comment) then *ppStmt is set to NULL. 3054 ** The calling procedure is responsible for deleting the compiled 3055 ** SQL statement using [sqlite3_finalize()] after it has finished with it. 3056 ** ppStmt may not be NULL. 3057 ** 3058 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3059 ** otherwise an [error code] is returned. 3060 ** 3061 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 3062 ** recommended for all new programs. The two older interfaces are retained 3063 ** for backwards compatibility, but their use is discouraged. 3064 ** ^In the "v2" interfaces, the prepared statement 3065 ** that is returned (the [sqlite3_stmt] object) contains a copy of the 3066 ** original SQL text. This causes the [sqlite3_step()] interface to 3067 ** behave differently in three ways: 3068 ** 3069 ** <ol> 3070 ** <li> 3071 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3072 ** always used to do, [sqlite3_step()] will automatically recompile the SQL 3073 ** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3074 ** retries will occur before sqlite3_step() gives up and returns an error. 3075 ** </li> 3076 ** 3077 ** <li> 3078 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3079 ** [error codes] or [extended error codes]. ^The legacy behavior was that 3080 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3081 ** and the application would have to make a second call to [sqlite3_reset()] 3082 ** in order to find the underlying cause of the problem. With the "v2" prepare 3083 ** interfaces, the underlying reason for the error is returned immediately. 3084 ** </li> 3085 ** 3086 ** <li> 3087 ** ^If the specific value bound to [parameter | host parameter] in the 3088 ** WHERE clause might influence the choice of query plan for a statement, 3089 ** then the statement will be automatically recompiled, as if there had been 3090 ** a schema change, on the first [sqlite3_step()] call following any change 3091 ** to the [sqlite3_bind_text | bindings] of that [parameter]. 3092 ** ^The specific value of WHERE-clause [parameter] might influence the 3093 ** choice of query plan if the parameter is the left-hand side of a [LIKE] 3094 ** or [GLOB] operator or if the parameter is compared to an indexed column 3095 ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3096 ** the 3097 ** </li> 3098 ** </ol> 3099 */ 3100 SQLITE_API int sqlite3_prepare( 3101 sqlite3 *db, /* Database handle */ 3102 const char *zSql, /* SQL statement, UTF-8 encoded */ 3103 int nByte, /* Maximum length of zSql in bytes. */ 3104 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3105 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3106 ); 3107 SQLITE_API int sqlite3_prepare_v2( 3108 sqlite3 *db, /* Database handle */ 3109 const char *zSql, /* SQL statement, UTF-8 encoded */ 3110 int nByte, /* Maximum length of zSql in bytes. */ 3111 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3112 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3113 ); 3114 SQLITE_API int sqlite3_prepare16( 3115 sqlite3 *db, /* Database handle */ 3116 const void *zSql, /* SQL statement, UTF-16 encoded */ 3117 int nByte, /* Maximum length of zSql in bytes. */ 3118 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3119 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3120 ); 3121 SQLITE_API int sqlite3_prepare16_v2( 3122 sqlite3 *db, /* Database handle */ 3123 const void *zSql, /* SQL statement, UTF-16 encoded */ 3124 int nByte, /* Maximum length of zSql in bytes. */ 3125 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3126 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3127 ); 3128 3129 /* 3130 ** CAPI3REF: Retrieving Statement SQL 3131 ** 3132 ** ^This interface can be used to retrieve a saved copy of the original 3133 ** SQL text used to create a [prepared statement] if that statement was 3134 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 3135 */ 3136 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt); 3137 3138 /* 3139 ** CAPI3REF: Determine If An SQL Statement Writes The Database 3140 ** 3141 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3142 ** and only if the [prepared statement] X makes no direct changes to 3143 ** the content of the database file. 3144 ** 3145 ** Note that [application-defined SQL functions] or 3146 ** [virtual tables] might change the database indirectly as a side effect. 3147 ** ^(For example, if an application defines a function "eval()" that 3148 ** calls [sqlite3_exec()], then the following SQL statement would 3149 ** change the database file through side-effects: 3150 ** 3151 ** <blockquote><pre> 3152 ** SELECT eval('DELETE FROM t1') FROM t2; 3153 ** </pre></blockquote> 3154 ** 3155 ** But because the [SELECT] statement does not change the database file 3156 ** directly, sqlite3_stmt_readonly() would still return true.)^ 3157 ** 3158 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3159 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3160 ** since the statements themselves do not actually modify the database but 3161 ** rather they control the timing of when other statements modify the 3162 ** database. ^The [ATTACH] and [DETACH] statements also cause 3163 ** sqlite3_stmt_readonly() to return true since, while those statements 3164 ** change the configuration of a database connection, they do not make 3165 ** changes to the content of the database files on disk. 3166 */ 3167 SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3168 3169 /* 3170 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3171 ** 3172 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3173 ** [prepared statement] S has been stepped at least once using 3174 ** [sqlite3_step(S)] but has not run to completion and/or has not 3175 ** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3176 ** interface returns false if S is a NULL pointer. If S is not a 3177 ** NULL pointer and is not a pointer to a valid [prepared statement] 3178 ** object, then the behavior is undefined and probably undesirable. 3179 ** 3180 ** This interface can be used in combination [sqlite3_next_stmt()] 3181 ** to locate all prepared statements associated with a database 3182 ** connection that are in need of being reset. This can be used, 3183 ** for example, in diagnostic routines to search for prepared 3184 ** statements that are holding a transaction open. 3185 */ 3186 SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*); 3187 3188 /* 3189 ** CAPI3REF: Dynamically Typed Value Object 3190 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3191 ** 3192 ** SQLite uses the sqlite3_value object to represent all values 3193 ** that can be stored in a database table. SQLite uses dynamic typing 3194 ** for the values it stores. ^Values stored in sqlite3_value objects 3195 ** can be integers, floating point values, strings, BLOBs, or NULL. 3196 ** 3197 ** An sqlite3_value object may be either "protected" or "unprotected". 3198 ** Some interfaces require a protected sqlite3_value. Other interfaces 3199 ** will accept either a protected or an unprotected sqlite3_value. 3200 ** Every interface that accepts sqlite3_value arguments specifies 3201 ** whether or not it requires a protected sqlite3_value. 3202 ** 3203 ** The terms "protected" and "unprotected" refer to whether or not 3204 ** a mutex is held. An internal mutex is held for a protected 3205 ** sqlite3_value object but no mutex is held for an unprotected 3206 ** sqlite3_value object. If SQLite is compiled to be single-threaded 3207 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3208 ** or if SQLite is run in one of reduced mutex modes 3209 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3210 ** then there is no distinction between protected and unprotected 3211 ** sqlite3_value objects and they can be used interchangeably. However, 3212 ** for maximum code portability it is recommended that applications 3213 ** still make the distinction between protected and unprotected 3214 ** sqlite3_value objects even when not strictly required. 3215 ** 3216 ** ^The sqlite3_value objects that are passed as parameters into the 3217 ** implementation of [application-defined SQL functions] are protected. 3218 ** ^The sqlite3_value object returned by 3219 ** [sqlite3_column_value()] is unprotected. 3220 ** Unprotected sqlite3_value objects may only be used with 3221 ** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3222 ** The [sqlite3_value_blob | sqlite3_value_type()] family of 3223 ** interfaces require protected sqlite3_value objects. 3224 */ 3225 typedef struct Mem sqlite3_value; 3226 3227 /* 3228 ** CAPI3REF: SQL Function Context Object 3229 ** 3230 ** The context in which an SQL function executes is stored in an 3231 ** sqlite3_context object. ^A pointer to an sqlite3_context object 3232 ** is always first parameter to [application-defined SQL functions]. 3233 ** The application-defined SQL function implementation will pass this 3234 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3235 ** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3236 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3237 ** and/or [sqlite3_set_auxdata()]. 3238 */ 3239 typedef struct sqlite3_context sqlite3_context; 3240 3241 /* 3242 ** CAPI3REF: Binding Values To Prepared Statements 3243 ** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3244 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3245 ** 3246 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3247 ** literals may be replaced by a [parameter] that matches one of following 3248 ** templates: 3249 ** 3250 ** <ul> 3251 ** <li> ? 3252 ** <li> ?NNN 3253 ** <li> :VVV 3254 ** <li> @VVV 3255 ** <li> $VVV 3256 ** </ul> 3257 ** 3258 ** In the templates above, NNN represents an integer literal, 3259 ** and VVV represents an alphanumeric identifier.)^ ^The values of these 3260 ** parameters (also called "host parameter names" or "SQL parameters") 3261 ** can be set using the sqlite3_bind_*() routines defined here. 3262 ** 3263 ** ^The first argument to the sqlite3_bind_*() routines is always 3264 ** a pointer to the [sqlite3_stmt] object returned from 3265 ** [sqlite3_prepare_v2()] or its variants. 3266 ** 3267 ** ^The second argument is the index of the SQL parameter to be set. 3268 ** ^The leftmost SQL parameter has an index of 1. ^When the same named 3269 ** SQL parameter is used more than once, second and subsequent 3270 ** occurrences have the same index as the first occurrence. 3271 ** ^The index for named parameters can be looked up using the 3272 ** [sqlite3_bind_parameter_index()] API if desired. ^The index 3273 ** for "?NNN" parameters is the value of NNN. 3274 ** ^The NNN value must be between 1 and the [sqlite3_limit()] 3275 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3276 ** 3277 ** ^The third argument is the value to bind to the parameter. 3278 ** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3279 ** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3280 ** is ignored and the end result is the same as sqlite3_bind_null(). 3281 ** 3282 ** ^(In those routines that have a fourth argument, its value is the 3283 ** number of bytes in the parameter. To be clear: the value is the 3284 ** number of <u>bytes</u> in the value, not the number of characters.)^ 3285 ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3286 ** is negative, then the length of the string is 3287 ** the number of bytes up to the first zero terminator. 3288 ** If the fourth parameter to sqlite3_bind_blob() is negative, then 3289 ** the behavior is undefined. 3290 ** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3291 ** or sqlite3_bind_text16() then that parameter must be the byte offset 3292 ** where the NUL terminator would occur assuming the string were NUL 3293 ** terminated. If any NUL characters occur at byte offsets less than 3294 ** the value of the fourth parameter then the resulting string value will 3295 ** contain embedded NULs. The result of expressions involving strings 3296 ** with embedded NULs is undefined. 3297 ** 3298 ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 3299 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 3300 ** string after SQLite has finished with it. ^The destructor is called 3301 ** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(), 3302 ** sqlite3_bind_text(), or sqlite3_bind_text16() fails. 3303 ** ^If the fifth argument is 3304 ** the special value [SQLITE_STATIC], then SQLite assumes that the 3305 ** information is in static, unmanaged space and does not need to be freed. 3306 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3307 ** SQLite makes its own private copy of the data immediately, before 3308 ** the sqlite3_bind_*() routine returns. 3309 ** 3310 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3311 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3312 ** (just an integer to hold its size) while it is being processed. 3313 ** Zeroblobs are intended to serve as placeholders for BLOBs whose 3314 ** content is later written using 3315 ** [sqlite3_blob_open | incremental BLOB I/O] routines. 3316 ** ^A negative value for the zeroblob results in a zero-length BLOB. 3317 ** 3318 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3319 ** for the [prepared statement] or with a prepared statement for which 3320 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3321 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3322 ** routine is passed a [prepared statement] that has been finalized, the 3323 ** result is undefined and probably harmful. 3324 ** 3325 ** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3326 ** ^Unbound parameters are interpreted as NULL. 3327 ** 3328 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3329 ** [error code] if anything goes wrong. 3330 ** ^[SQLITE_RANGE] is returned if the parameter 3331 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3332 ** 3333 ** See also: [sqlite3_bind_parameter_count()], 3334 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3335 */ 3336 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3337 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double); 3338 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int); 3339 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3340 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int); 3341 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 3342 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3343 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3344 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3345 3346 /* 3347 ** CAPI3REF: Number Of SQL Parameters 3348 ** 3349 ** ^This routine can be used to find the number of [SQL parameters] 3350 ** in a [prepared statement]. SQL parameters are tokens of the 3351 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3352 ** placeholders for values that are [sqlite3_bind_blob | bound] 3353 ** to the parameters at a later time. 3354 ** 3355 ** ^(This routine actually returns the index of the largest (rightmost) 3356 ** parameter. For all forms except ?NNN, this will correspond to the 3357 ** number of unique parameters. If parameters of the ?NNN form are used, 3358 ** there may be gaps in the list.)^ 3359 ** 3360 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 3361 ** [sqlite3_bind_parameter_name()], and 3362 ** [sqlite3_bind_parameter_index()]. 3363 */ 3364 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*); 3365 3366 /* 3367 ** CAPI3REF: Name Of A Host Parameter 3368 ** 3369 ** ^The sqlite3_bind_parameter_name(P,N) interface returns 3370 ** the name of the N-th [SQL parameter] in the [prepared statement] P. 3371 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3372 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3373 ** respectively. 3374 ** In other words, the initial ":" or "$" or "@" or "?" 3375 ** is included as part of the name.)^ 3376 ** ^Parameters of the form "?" without a following integer have no name 3377 ** and are referred to as "nameless" or "anonymous parameters". 3378 ** 3379 ** ^The first host parameter has an index of 1, not 0. 3380 ** 3381 ** ^If the value N is out of range or if the N-th parameter is 3382 ** nameless, then NULL is returned. ^The returned string is 3383 ** always in UTF-8 encoding even if the named parameter was 3384 ** originally specified as UTF-16 in [sqlite3_prepare16()] or 3385 ** [sqlite3_prepare16_v2()]. 3386 ** 3387 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 3388 ** [sqlite3_bind_parameter_count()], and 3389 ** [sqlite3_bind_parameter_index()]. 3390 */ 3391 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3392 3393 /* 3394 ** CAPI3REF: Index Of A Parameter With A Given Name 3395 ** 3396 ** ^Return the index of an SQL parameter given its name. ^The 3397 ** index value returned is suitable for use as the second 3398 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3399 ** is returned if no matching parameter is found. ^The parameter 3400 ** name must be given in UTF-8 even if the original statement 3401 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3402 ** 3403 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 3404 ** [sqlite3_bind_parameter_count()], and 3405 ** [sqlite3_bind_parameter_index()]. 3406 */ 3407 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3408 3409 /* 3410 ** CAPI3REF: Reset All Bindings On A Prepared Statement 3411 ** 3412 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3413 ** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3414 ** ^Use this routine to reset all host parameters to NULL. 3415 */ 3416 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*); 3417 3418 /* 3419 ** CAPI3REF: Number Of Columns In A Result Set 3420 ** 3421 ** ^Return the number of columns in the result set returned by the 3422 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3423 ** statement that does not return data (for example an [UPDATE]). 3424 ** 3425 ** See also: [sqlite3_data_count()] 3426 */ 3427 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt); 3428 3429 /* 3430 ** CAPI3REF: Column Names In A Result Set 3431 ** 3432 ** ^These routines return the name assigned to a particular column 3433 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3434 ** interface returns a pointer to a zero-terminated UTF-8 string 3435 ** and sqlite3_column_name16() returns a pointer to a zero-terminated 3436 ** UTF-16 string. ^The first parameter is the [prepared statement] 3437 ** that implements the [SELECT] statement. ^The second parameter is the 3438 ** column number. ^The leftmost column is number 0. 3439 ** 3440 ** ^The returned string pointer is valid until either the [prepared statement] 3441 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3442 ** reprepared by the first call to [sqlite3_step()] for a particular run 3443 ** or until the next call to 3444 ** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3445 ** 3446 ** ^If sqlite3_malloc() fails during the processing of either routine 3447 ** (for example during a conversion from UTF-8 to UTF-16) then a 3448 ** NULL pointer is returned. 3449 ** 3450 ** ^The name of a result column is the value of the "AS" clause for 3451 ** that column, if there is an AS clause. If there is no AS clause 3452 ** then the name of the column is unspecified and may change from 3453 ** one release of SQLite to the next. 3454 */ 3455 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N); 3456 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3457 3458 /* 3459 ** CAPI3REF: Source Of Data In A Query Result 3460 ** 3461 ** ^These routines provide a means to determine the database, table, and 3462 ** table column that is the origin of a particular result column in 3463 ** [SELECT] statement. 3464 ** ^The name of the database or table or column can be returned as 3465 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3466 ** the database name, the _table_ routines return the table name, and 3467 ** the origin_ routines return the column name. 3468 ** ^The returned string is valid until the [prepared statement] is destroyed 3469 ** using [sqlite3_finalize()] or until the statement is automatically 3470 ** reprepared by the first call to [sqlite3_step()] for a particular run 3471 ** or until the same information is requested 3472 ** again in a different encoding. 3473 ** 3474 ** ^The names returned are the original un-aliased names of the 3475 ** database, table, and column. 3476 ** 3477 ** ^The first argument to these interfaces is a [prepared statement]. 3478 ** ^These functions return information about the Nth result column returned by 3479 ** the statement, where N is the second function argument. 3480 ** ^The left-most column is column 0 for these routines. 3481 ** 3482 ** ^If the Nth column returned by the statement is an expression or 3483 ** subquery and is not a column value, then all of these functions return 3484 ** NULL. ^These routine might also return NULL if a memory allocation error 3485 ** occurs. ^Otherwise, they return the name of the attached database, table, 3486 ** or column that query result column was extracted from. 3487 ** 3488 ** ^As with all other SQLite APIs, those whose names end with "16" return 3489 ** UTF-16 encoded strings and the other functions return UTF-8. 3490 ** 3491 ** ^These APIs are only available if the library was compiled with the 3492 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3493 ** 3494 ** If two or more threads call one or more of these routines against the same 3495 ** prepared statement and column at the same time then the results are 3496 ** undefined. 3497 ** 3498 ** If two or more threads call one or more 3499 ** [sqlite3_column_database_name | column metadata interfaces] 3500 ** for the same [prepared statement] and result column 3501 ** at the same time then the results are undefined. 3502 */ 3503 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3504 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3505 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3506 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3507 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3508 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3509 3510 /* 3511 ** CAPI3REF: Declared Datatype Of A Query Result 3512 ** 3513 ** ^(The first parameter is a [prepared statement]. 3514 ** If this statement is a [SELECT] statement and the Nth column of the 3515 ** returned result set of that [SELECT] is a table column (not an 3516 ** expression or subquery) then the declared type of the table 3517 ** column is returned.)^ ^If the Nth column of the result set is an 3518 ** expression or subquery, then a NULL pointer is returned. 3519 ** ^The returned string is always UTF-8 encoded. 3520 ** 3521 ** ^(For example, given the database schema: 3522 ** 3523 ** CREATE TABLE t1(c1 VARIANT); 3524 ** 3525 ** and the following statement to be compiled: 3526 ** 3527 ** SELECT c1 + 1, c1 FROM t1; 3528 ** 3529 ** this routine would return the string "VARIANT" for the second result 3530 ** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3531 ** 3532 ** ^SQLite uses dynamic run-time typing. ^So just because a column 3533 ** is declared to contain a particular type does not mean that the 3534 ** data stored in that column is of the declared type. SQLite is 3535 ** strongly typed, but the typing is dynamic not static. ^Type 3536 ** is associated with individual values, not with the containers 3537 ** used to hold those values. 3538 */ 3539 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3540 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3541 3542 /* 3543 ** CAPI3REF: Evaluate An SQL Statement 3544 ** 3545 ** After a [prepared statement] has been prepared using either 3546 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3547 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3548 ** must be called one or more times to evaluate the statement. 3549 ** 3550 ** The details of the behavior of the sqlite3_step() interface depend 3551 ** on whether the statement was prepared using the newer "v2" interface 3552 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3553 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3554 ** new "v2" interface is recommended for new applications but the legacy 3555 ** interface will continue to be supported. 3556 ** 3557 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3558 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3559 ** ^With the "v2" interface, any of the other [result codes] or 3560 ** [extended result codes] might be returned as well. 3561 ** 3562 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3563 ** database locks it needs to do its job. ^If the statement is a [COMMIT] 3564 ** or occurs outside of an explicit transaction, then you can retry the 3565 ** statement. If the statement is not a [COMMIT] and occurs within an 3566 ** explicit transaction then you should rollback the transaction before 3567 ** continuing. 3568 ** 3569 ** ^[SQLITE_DONE] means that the statement has finished executing 3570 ** successfully. sqlite3_step() should not be called again on this virtual 3571 ** machine without first calling [sqlite3_reset()] to reset the virtual 3572 ** machine back to its initial state. 3573 ** 3574 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3575 ** is returned each time a new row of data is ready for processing by the 3576 ** caller. The values may be accessed using the [column access functions]. 3577 ** sqlite3_step() is called again to retrieve the next row of data. 3578 ** 3579 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3580 ** violation) has occurred. sqlite3_step() should not be called again on 3581 ** the VM. More information may be found by calling [sqlite3_errmsg()]. 3582 ** ^With the legacy interface, a more specific error code (for example, 3583 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3584 ** can be obtained by calling [sqlite3_reset()] on the 3585 ** [prepared statement]. ^In the "v2" interface, 3586 ** the more specific error code is returned directly by sqlite3_step(). 3587 ** 3588 ** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3589 ** Perhaps it was called on a [prepared statement] that has 3590 ** already been [sqlite3_finalize | finalized] or on one that had 3591 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3592 ** be the case that the same database connection is being used by two or 3593 ** more threads at the same moment in time. 3594 ** 3595 ** For all versions of SQLite up to and including 3.6.23.1, a call to 3596 ** [sqlite3_reset()] was required after sqlite3_step() returned anything 3597 ** other than [SQLITE_ROW] before any subsequent invocation of 3598 ** sqlite3_step(). Failure to reset the prepared statement using 3599 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3600 ** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3601 ** calling [sqlite3_reset()] automatically in this circumstance rather 3602 ** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3603 ** break because any application that ever receives an SQLITE_MISUSE error 3604 ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3605 ** can be used to restore the legacy behavior. 3606 ** 3607 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3608 ** API always returns a generic error code, [SQLITE_ERROR], following any 3609 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3610 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3611 ** specific [error codes] that better describes the error. 3612 ** We admit that this is a goofy design. The problem has been fixed 3613 ** with the "v2" interface. If you prepare all of your SQL statements 3614 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3615 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3616 ** then the more specific [error codes] are returned directly 3617 ** by sqlite3_step(). The use of the "v2" interface is recommended. 3618 */ 3619 SQLITE_API int sqlite3_step(sqlite3_stmt*); 3620 3621 /* 3622 ** CAPI3REF: Number of columns in a result set 3623 ** 3624 ** ^The sqlite3_data_count(P) interface returns the number of columns in the 3625 ** current row of the result set of [prepared statement] P. 3626 ** ^If prepared statement P does not have results ready to return 3627 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3628 ** interfaces) then sqlite3_data_count(P) returns 0. 3629 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3630 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 3631 ** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 3632 ** will return non-zero if previous call to [sqlite3_step](P) returned 3633 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 3634 ** where it always returns zero since each step of that multi-step 3635 ** pragma returns 0 columns of data. 3636 ** 3637 ** See also: [sqlite3_column_count()] 3638 */ 3639 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt); 3640 3641 /* 3642 ** CAPI3REF: Fundamental Datatypes 3643 ** KEYWORDS: SQLITE_TEXT 3644 ** 3645 ** ^(Every value in SQLite has one of five fundamental datatypes: 3646 ** 3647 ** <ul> 3648 ** <li> 64-bit signed integer 3649 ** <li> 64-bit IEEE floating point number 3650 ** <li> string 3651 ** <li> BLOB 3652 ** <li> NULL 3653 ** </ul>)^ 3654 ** 3655 ** These constants are codes for each of those types. 3656 ** 3657 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3658 ** for a completely different meaning. Software that links against both 3659 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3660 ** SQLITE_TEXT. 3661 */ 3662 #define SQLITE_INTEGER 1 3663 #define SQLITE_FLOAT 2 3664 #define SQLITE_BLOB 4 3665 #define SQLITE_NULL 5 3666 #ifdef SQLITE_TEXT 3667 # undef SQLITE_TEXT 3668 #else 3669 # define SQLITE_TEXT 3 3670 #endif 3671 #define SQLITE3_TEXT 3 3672 3673 /* 3674 ** CAPI3REF: Result Values From A Query 3675 ** KEYWORDS: {column access functions} 3676 ** 3677 ** These routines form the "result set" interface. 3678 ** 3679 ** ^These routines return information about a single column of the current 3680 ** result row of a query. ^In every case the first argument is a pointer 3681 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3682 ** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3683 ** and the second argument is the index of the column for which information 3684 ** should be returned. ^The leftmost column of the result set has the index 0. 3685 ** ^The number of columns in the result can be determined using 3686 ** [sqlite3_column_count()]. 3687 ** 3688 ** If the SQL statement does not currently point to a valid row, or if the 3689 ** column index is out of range, the result is undefined. 3690 ** These routines may only be called when the most recent call to 3691 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3692 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3693 ** If any of these routines are called after [sqlite3_reset()] or 3694 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3695 ** something other than [SQLITE_ROW], the results are undefined. 3696 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3697 ** are called from a different thread while any of these routines 3698 ** are pending, then the results are undefined. 3699 ** 3700 ** ^The sqlite3_column_type() routine returns the 3701 ** [SQLITE_INTEGER | datatype code] for the initial data type 3702 ** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3703 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3704 ** returned by sqlite3_column_type() is only meaningful if no type 3705 ** conversions have occurred as described below. After a type conversion, 3706 ** the value returned by sqlite3_column_type() is undefined. Future 3707 ** versions of SQLite may change the behavior of sqlite3_column_type() 3708 ** following a type conversion. 3709 ** 3710 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3711 ** routine returns the number of bytes in that BLOB or string. 3712 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3713 ** the string to UTF-8 and then returns the number of bytes. 3714 ** ^If the result is a numeric value then sqlite3_column_bytes() uses 3715 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3716 ** the number of bytes in that string. 3717 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3718 ** 3719 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3720 ** routine returns the number of bytes in that BLOB or string. 3721 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3722 ** the string to UTF-16 and then returns the number of bytes. 3723 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3724 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3725 ** the number of bytes in that string. 3726 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3727 ** 3728 ** ^The values returned by [sqlite3_column_bytes()] and 3729 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3730 ** of the string. ^For clarity: the values returned by 3731 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3732 ** bytes in the string, not the number of characters. 3733 ** 3734 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3735 ** even empty strings, are always zero-terminated. ^The return 3736 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3737 ** 3738 ** ^The object returned by [sqlite3_column_value()] is an 3739 ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3740 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3741 ** If the [unprotected sqlite3_value] object returned by 3742 ** [sqlite3_column_value()] is used in any other way, including calls 3743 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3744 ** or [sqlite3_value_bytes()], then the behavior is undefined. 3745 ** 3746 ** These routines attempt to convert the value where appropriate. ^For 3747 ** example, if the internal representation is FLOAT and a text result 3748 ** is requested, [sqlite3_snprintf()] is used internally to perform the 3749 ** conversion automatically. ^(The following table details the conversions 3750 ** that are applied: 3751 ** 3752 ** <blockquote> 3753 ** <table border="1"> 3754 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3755 ** 3756 ** <tr><td> NULL <td> INTEGER <td> Result is 0 3757 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3758 ** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3759 ** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3760 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3761 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3762 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3763 ** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3764 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3765 ** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3766 ** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3767 ** <tr><td> TEXT <td> FLOAT <td> Use atof() 3768 ** <tr><td> TEXT <td> BLOB <td> No change 3769 ** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3770 ** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3771 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3772 ** </table> 3773 ** </blockquote>)^ 3774 ** 3775 ** The table above makes reference to standard C library functions atoi() 3776 ** and atof(). SQLite does not really use these functions. It has its 3777 ** own equivalent internal routines. The atoi() and atof() names are 3778 ** used in the table for brevity and because they are familiar to most 3779 ** C programmers. 3780 ** 3781 ** Note that when type conversions occur, pointers returned by prior 3782 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3783 ** sqlite3_column_text16() may be invalidated. 3784 ** Type conversions and pointer invalidations might occur 3785 ** in the following cases: 3786 ** 3787 ** <ul> 3788 ** <li> The initial content is a BLOB and sqlite3_column_text() or 3789 ** sqlite3_column_text16() is called. A zero-terminator might 3790 ** need to be added to the string.</li> 3791 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3792 ** sqlite3_column_text16() is called. The content must be converted 3793 ** to UTF-16.</li> 3794 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3795 ** sqlite3_column_text() is called. The content must be converted 3796 ** to UTF-8.</li> 3797 ** </ul> 3798 ** 3799 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3800 ** not invalidate a prior pointer, though of course the content of the buffer 3801 ** that the prior pointer references will have been modified. Other kinds 3802 ** of conversion are done in place when it is possible, but sometimes they 3803 ** are not possible and in those cases prior pointers are invalidated. 3804 ** 3805 ** The safest and easiest to remember policy is to invoke these routines 3806 ** in one of the following ways: 3807 ** 3808 ** <ul> 3809 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3810 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3811 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3812 ** </ul> 3813 ** 3814 ** In other words, you should call sqlite3_column_text(), 3815 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3816 ** into the desired format, then invoke sqlite3_column_bytes() or 3817 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3818 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3819 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3820 ** with calls to sqlite3_column_bytes(). 3821 ** 3822 ** ^The pointers returned are valid until a type conversion occurs as 3823 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3824 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3825 ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3826 ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3827 ** [sqlite3_free()]. 3828 ** 3829 ** ^(If a memory allocation error occurs during the evaluation of any 3830 ** of these routines, a default value is returned. The default value 3831 ** is either the integer 0, the floating point number 0.0, or a NULL 3832 ** pointer. Subsequent calls to [sqlite3_errcode()] will return 3833 ** [SQLITE_NOMEM].)^ 3834 */ 3835 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3836 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3837 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3838 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol); 3839 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol); 3840 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3841 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3842 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3843 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol); 3844 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3845 3846 /* 3847 ** CAPI3REF: Destroy A Prepared Statement Object 3848 ** 3849 ** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3850 ** ^If the most recent evaluation of the statement encountered no errors 3851 ** or if the statement is never been evaluated, then sqlite3_finalize() returns 3852 ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 3853 ** sqlite3_finalize(S) returns the appropriate [error code] or 3854 ** [extended error code]. 3855 ** 3856 ** ^The sqlite3_finalize(S) routine can be called at any point during 3857 ** the life cycle of [prepared statement] S: 3858 ** before statement S is ever evaluated, after 3859 ** one or more calls to [sqlite3_reset()], or after any call 3860 ** to [sqlite3_step()] regardless of whether or not the statement has 3861 ** completed execution. 3862 ** 3863 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 3864 ** 3865 ** The application must finalize every [prepared statement] in order to avoid 3866 ** resource leaks. It is a grievous error for the application to try to use 3867 ** a prepared statement after it has been finalized. Any use of a prepared 3868 ** statement after it has been finalized can result in undefined and 3869 ** undesirable behavior such as segfaults and heap corruption. 3870 */ 3871 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt); 3872 3873 /* 3874 ** CAPI3REF: Reset A Prepared Statement Object 3875 ** 3876 ** The sqlite3_reset() function is called to reset a [prepared statement] 3877 ** object back to its initial state, ready to be re-executed. 3878 ** ^Any SQL statement variables that had values bound to them using 3879 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3880 ** Use [sqlite3_clear_bindings()] to reset the bindings. 3881 ** 3882 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3883 ** back to the beginning of its program. 3884 ** 3885 ** ^If the most recent call to [sqlite3_step(S)] for the 3886 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3887 ** or if [sqlite3_step(S)] has never before been called on S, 3888 ** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3889 ** 3890 ** ^If the most recent call to [sqlite3_step(S)] for the 3891 ** [prepared statement] S indicated an error, then 3892 ** [sqlite3_reset(S)] returns an appropriate [error code]. 3893 ** 3894 ** ^The [sqlite3_reset(S)] interface does not change the values 3895 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3896 */ 3897 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt); 3898 3899 /* 3900 ** CAPI3REF: Create Or Redefine SQL Functions 3901 ** KEYWORDS: {function creation routines} 3902 ** KEYWORDS: {application-defined SQL function} 3903 ** KEYWORDS: {application-defined SQL functions} 3904 ** 3905 ** ^These functions (collectively known as "function creation routines") 3906 ** are used to add SQL functions or aggregates or to redefine the behavior 3907 ** of existing SQL functions or aggregates. The only differences between 3908 ** these routines are the text encoding expected for 3909 ** the second parameter (the name of the function being created) 3910 ** and the presence or absence of a destructor callback for 3911 ** the application data pointer. 3912 ** 3913 ** ^The first parameter is the [database connection] to which the SQL 3914 ** function is to be added. ^If an application uses more than one database 3915 ** connection then application-defined SQL functions must be added 3916 ** to each database connection separately. 3917 ** 3918 ** ^The second parameter is the name of the SQL function to be created or 3919 ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 3920 ** representation, exclusive of the zero-terminator. ^Note that the name 3921 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 3922 ** ^Any attempt to create a function with a longer name 3923 ** will result in [SQLITE_MISUSE] being returned. 3924 ** 3925 ** ^The third parameter (nArg) 3926 ** is the number of arguments that the SQL function or 3927 ** aggregate takes. ^If this parameter is -1, then the SQL function or 3928 ** aggregate may take any number of arguments between 0 and the limit 3929 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3930 ** parameter is less than -1 or greater than 127 then the behavior is 3931 ** undefined. 3932 ** 3933 ** ^The fourth parameter, eTextRep, specifies what 3934 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3935 ** its parameters. Every SQL function implementation must be able to work 3936 ** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3937 ** more efficient with one encoding than another. ^An application may 3938 ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3939 ** times with the same function but with different values of eTextRep. 3940 ** ^When multiple implementations of the same function are available, SQLite 3941 ** will pick the one that involves the least amount of data conversion. 3942 ** If there is only a single implementation which does not care what text 3943 ** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3944 ** 3945 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3946 ** function can gain access to this pointer using [sqlite3_user_data()].)^ 3947 ** 3948 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 3949 ** pointers to C-language functions that implement the SQL function or 3950 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3951 ** callback only; NULL pointers must be passed as the xStep and xFinal 3952 ** parameters. ^An aggregate SQL function requires an implementation of xStep 3953 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 3954 ** SQL function or aggregate, pass NULL pointers for all three function 3955 ** callbacks. 3956 ** 3957 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 3958 ** then it is destructor for the application data pointer. 3959 ** The destructor is invoked when the function is deleted, either by being 3960 ** overloaded or when the database connection closes.)^ 3961 ** ^The destructor is also invoked if the call to 3962 ** sqlite3_create_function_v2() fails. 3963 ** ^When the destructor callback of the tenth parameter is invoked, it 3964 ** is passed a single argument which is a copy of the application data 3965 ** pointer which was the fifth parameter to sqlite3_create_function_v2(). 3966 ** 3967 ** ^It is permitted to register multiple implementations of the same 3968 ** functions with the same name but with either differing numbers of 3969 ** arguments or differing preferred text encodings. ^SQLite will use 3970 ** the implementation that most closely matches the way in which the 3971 ** SQL function is used. ^A function implementation with a non-negative 3972 ** nArg parameter is a better match than a function implementation with 3973 ** a negative nArg. ^A function where the preferred text encoding 3974 ** matches the database encoding is a better 3975 ** match than a function where the encoding is different. 3976 ** ^A function where the encoding difference is between UTF16le and UTF16be 3977 ** is a closer match than a function where the encoding difference is 3978 ** between UTF8 and UTF16. 3979 ** 3980 ** ^Built-in functions may be overloaded by new application-defined functions. 3981 ** 3982 ** ^An application-defined function is permitted to call other 3983 ** SQLite interfaces. However, such calls must not 3984 ** close the database connection nor finalize or reset the prepared 3985 ** statement in which the function is running. 3986 */ 3987 SQLITE_API int sqlite3_create_function( 3988 sqlite3 *db, 3989 const char *zFunctionName, 3990 int nArg, 3991 int eTextRep, 3992 void *pApp, 3993 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3994 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3995 void (*xFinal)(sqlite3_context*) 3996 ); 3997 SQLITE_API int sqlite3_create_function16( 3998 sqlite3 *db, 3999 const void *zFunctionName, 4000 int nArg, 4001 int eTextRep, 4002 void *pApp, 4003 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4004 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4005 void (*xFinal)(sqlite3_context*) 4006 ); 4007 SQLITE_API int sqlite3_create_function_v2( 4008 sqlite3 *db, 4009 const char *zFunctionName, 4010 int nArg, 4011 int eTextRep, 4012 void *pApp, 4013 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4014 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4015 void (*xFinal)(sqlite3_context*), 4016 void(*xDestroy)(void*) 4017 ); 4018 4019 /* 4020 ** CAPI3REF: Text Encodings 4021 ** 4022 ** These constant define integer codes that represent the various 4023 ** text encodings supported by SQLite. 4024 */ 4025 #define SQLITE_UTF8 1 4026 #define SQLITE_UTF16LE 2 4027 #define SQLITE_UTF16BE 3 4028 #define SQLITE_UTF16 4 /* Use native byte order */ 4029 #define SQLITE_ANY 5 /* sqlite3_create_function only */ 4030 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4031 4032 /* 4033 ** CAPI3REF: Deprecated Functions 4034 ** DEPRECATED 4035 ** 4036 ** These functions are [deprecated]. In order to maintain 4037 ** backwards compatibility with older code, these functions continue 4038 ** to be supported. However, new applications should avoid 4039 ** the use of these functions. To help encourage people to avoid 4040 ** using these functions, we are not going to tell you what they do. 4041 */ 4042 #ifndef SQLITE_OMIT_DEPRECATED 4043 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4044 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4045 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4046 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void); 4047 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4048 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4049 void*,sqlite3_int64); 4050 #endif 4051 4052 /* 4053 ** CAPI3REF: Obtaining SQL Function Parameter Values 4054 ** 4055 ** The C-language implementation of SQL functions and aggregates uses 4056 ** this set of interface routines to access the parameter values on 4057 ** the function or aggregate. 4058 ** 4059 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters 4060 ** to [sqlite3_create_function()] and [sqlite3_create_function16()] 4061 ** define callbacks that implement the SQL functions and aggregates. 4062 ** The 3rd parameter to these callbacks is an array of pointers to 4063 ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 4064 ** each parameter to the SQL function. These routines are used to 4065 ** extract values from the [sqlite3_value] objects. 4066 ** 4067 ** These routines work only with [protected sqlite3_value] objects. 4068 ** Any attempt to use these routines on an [unprotected sqlite3_value] 4069 ** object results in undefined behavior. 4070 ** 4071 ** ^These routines work just like the corresponding [column access functions] 4072 ** except that these routines take a single [protected sqlite3_value] object 4073 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4074 ** 4075 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4076 ** in the native byte-order of the host machine. ^The 4077 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4078 ** extract UTF-16 strings as big-endian and little-endian respectively. 4079 ** 4080 ** ^(The sqlite3_value_numeric_type() interface attempts to apply 4081 ** numeric affinity to the value. This means that an attempt is 4082 ** made to convert the value to an integer or floating point. If 4083 ** such a conversion is possible without loss of information (in other 4084 ** words, if the value is a string that looks like a number) 4085 ** then the conversion is performed. Otherwise no conversion occurs. 4086 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4087 ** 4088 ** Please pay particular attention to the fact that the pointer returned 4089 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4090 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4091 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4092 ** or [sqlite3_value_text16()]. 4093 ** 4094 ** These routines must be called from the same thread as 4095 ** the SQL function that supplied the [sqlite3_value*] parameters. 4096 */ 4097 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*); 4098 SQLITE_API int sqlite3_value_bytes(sqlite3_value*); 4099 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*); 4100 SQLITE_API double sqlite3_value_double(sqlite3_value*); 4101 SQLITE_API int sqlite3_value_int(sqlite3_value*); 4102 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4103 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*); 4104 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*); 4105 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*); 4106 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*); 4107 SQLITE_API int sqlite3_value_type(sqlite3_value*); 4108 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*); 4109 4110 /* 4111 ** CAPI3REF: Obtain Aggregate Function Context 4112 ** 4113 ** Implementations of aggregate SQL functions use this 4114 ** routine to allocate memory for storing their state. 4115 ** 4116 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4117 ** for a particular aggregate function, SQLite 4118 ** allocates N of memory, zeroes out that memory, and returns a pointer 4119 ** to the new memory. ^On second and subsequent calls to 4120 ** sqlite3_aggregate_context() for the same aggregate function instance, 4121 ** the same buffer is returned. Sqlite3_aggregate_context() is normally 4122 ** called once for each invocation of the xStep callback and then one 4123 ** last time when the xFinal callback is invoked. ^(When no rows match 4124 ** an aggregate query, the xStep() callback of the aggregate function 4125 ** implementation is never called and xFinal() is called exactly once. 4126 ** In those cases, sqlite3_aggregate_context() might be called for the 4127 ** first time from within xFinal().)^ 4128 ** 4129 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4130 ** when first called if N is less than or equal to zero or if a memory 4131 ** allocate error occurs. 4132 ** 4133 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4134 ** determined by the N parameter on first successful call. Changing the 4135 ** value of N in subsequent call to sqlite3_aggregate_context() within 4136 ** the same aggregate function instance will not resize the memory 4137 ** allocation.)^ Within the xFinal callback, it is customary to set 4138 ** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4139 ** pointless memory allocations occur. 4140 ** 4141 ** ^SQLite automatically frees the memory allocated by 4142 ** sqlite3_aggregate_context() when the aggregate query concludes. 4143 ** 4144 ** The first parameter must be a copy of the 4145 ** [sqlite3_context | SQL function context] that is the first parameter 4146 ** to the xStep or xFinal callback routine that implements the aggregate 4147 ** function. 4148 ** 4149 ** This routine must be called from the same thread in which 4150 ** the aggregate SQL function is running. 4151 */ 4152 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4153 4154 /* 4155 ** CAPI3REF: User Data For Functions 4156 ** 4157 ** ^The sqlite3_user_data() interface returns a copy of 4158 ** the pointer that was the pUserData parameter (the 5th parameter) 4159 ** of the [sqlite3_create_function()] 4160 ** and [sqlite3_create_function16()] routines that originally 4161 ** registered the application defined function. 4162 ** 4163 ** This routine must be called from the same thread in which 4164 ** the application-defined function is running. 4165 */ 4166 SQLITE_API void *sqlite3_user_data(sqlite3_context*); 4167 4168 /* 4169 ** CAPI3REF: Database Connection For Functions 4170 ** 4171 ** ^The sqlite3_context_db_handle() interface returns a copy of 4172 ** the pointer to the [database connection] (the 1st parameter) 4173 ** of the [sqlite3_create_function()] 4174 ** and [sqlite3_create_function16()] routines that originally 4175 ** registered the application defined function. 4176 */ 4177 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4178 4179 /* 4180 ** CAPI3REF: Function Auxiliary Data 4181 ** 4182 ** The following two functions may be used by scalar SQL functions to 4183 ** associate metadata with argument values. If the same value is passed to 4184 ** multiple invocations of the same SQL function during query execution, under 4185 ** some circumstances the associated metadata may be preserved. This may 4186 ** be used, for example, to add a regular-expression matching scalar 4187 ** function. The compiled version of the regular expression is stored as 4188 ** metadata associated with the SQL value passed as the regular expression 4189 ** pattern. The compiled regular expression can be reused on multiple 4190 ** invocations of the same function so that the original pattern string 4191 ** does not need to be recompiled on each invocation. 4192 ** 4193 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4194 ** associated by the sqlite3_set_auxdata() function with the Nth argument 4195 ** value to the application-defined function. ^If no metadata has been ever 4196 ** been set for the Nth argument of the function, or if the corresponding 4197 ** function parameter has changed since the meta-data was set, 4198 ** then sqlite3_get_auxdata() returns a NULL pointer. 4199 ** 4200 ** ^The sqlite3_set_auxdata() interface saves the metadata 4201 ** pointed to by its 3rd parameter as the metadata for the N-th 4202 ** argument of the application-defined function. Subsequent 4203 ** calls to sqlite3_get_auxdata() might return this data, if it has 4204 ** not been destroyed. 4205 ** ^If it is not NULL, SQLite will invoke the destructor 4206 ** function given by the 4th parameter to sqlite3_set_auxdata() on 4207 ** the metadata when the corresponding function parameter changes 4208 ** or when the SQL statement completes, whichever comes first. 4209 ** 4210 ** SQLite is free to call the destructor and drop metadata on any 4211 ** parameter of any function at any time. ^The only guarantee is that 4212 ** the destructor will be called before the metadata is dropped. 4213 ** 4214 ** ^(In practice, metadata is preserved between function calls for 4215 ** expressions that are constant at compile time. This includes literal 4216 ** values and [parameters].)^ 4217 ** 4218 ** These routines must be called from the same thread in which 4219 ** the SQL function is running. 4220 */ 4221 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N); 4222 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4223 4224 4225 /* 4226 ** CAPI3REF: Constants Defining Special Destructor Behavior 4227 ** 4228 ** These are special values for the destructor that is passed in as the 4229 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4230 ** argument is SQLITE_STATIC, it means that the content pointer is constant 4231 ** and will never change. It does not need to be destroyed. ^The 4232 ** SQLITE_TRANSIENT value means that the content will likely change in 4233 ** the near future and that SQLite should make its own private copy of 4234 ** the content before returning. 4235 ** 4236 ** The typedef is necessary to work around problems in certain 4237 ** C++ compilers. 4238 */ 4239 typedef void (*sqlite3_destructor_type)(void*); 4240 #define SQLITE_STATIC ((sqlite3_destructor_type)0) 4241 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4242 4243 /* 4244 ** CAPI3REF: Setting The Result Of An SQL Function 4245 ** 4246 ** These routines are used by the xFunc or xFinal callbacks that 4247 ** implement SQL functions and aggregates. See 4248 ** [sqlite3_create_function()] and [sqlite3_create_function16()] 4249 ** for additional information. 4250 ** 4251 ** These functions work very much like the [parameter binding] family of 4252 ** functions used to bind values to host parameters in prepared statements. 4253 ** Refer to the [SQL parameter] documentation for additional information. 4254 ** 4255 ** ^The sqlite3_result_blob() interface sets the result from 4256 ** an application-defined function to be the BLOB whose content is pointed 4257 ** to by the second parameter and which is N bytes long where N is the 4258 ** third parameter. 4259 ** 4260 ** ^The sqlite3_result_zeroblob() interfaces set the result of 4261 ** the application-defined function to be a BLOB containing all zero 4262 ** bytes and N bytes in size, where N is the value of the 2nd parameter. 4263 ** 4264 ** ^The sqlite3_result_double() interface sets the result from 4265 ** an application-defined function to be a floating point value specified 4266 ** by its 2nd argument. 4267 ** 4268 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4269 ** cause the implemented SQL function to throw an exception. 4270 ** ^SQLite uses the string pointed to by the 4271 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4272 ** as the text of an error message. ^SQLite interprets the error 4273 ** message string from sqlite3_result_error() as UTF-8. ^SQLite 4274 ** interprets the string from sqlite3_result_error16() as UTF-16 in native 4275 ** byte order. ^If the third parameter to sqlite3_result_error() 4276 ** or sqlite3_result_error16() is negative then SQLite takes as the error 4277 ** message all text up through the first zero character. 4278 ** ^If the third parameter to sqlite3_result_error() or 4279 ** sqlite3_result_error16() is non-negative then SQLite takes that many 4280 ** bytes (not characters) from the 2nd parameter as the error message. 4281 ** ^The sqlite3_result_error() and sqlite3_result_error16() 4282 ** routines make a private copy of the error message text before 4283 ** they return. Hence, the calling function can deallocate or 4284 ** modify the text after they return without harm. 4285 ** ^The sqlite3_result_error_code() function changes the error code 4286 ** returned by SQLite as a result of an error in a function. ^By default, 4287 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4288 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4289 ** 4290 ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 4291 ** error indicating that a string or BLOB is too long to represent. 4292 ** 4293 ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 4294 ** error indicating that a memory allocation failed. 4295 ** 4296 ** ^The sqlite3_result_int() interface sets the return value 4297 ** of the application-defined function to be the 32-bit signed integer 4298 ** value given in the 2nd argument. 4299 ** ^The sqlite3_result_int64() interface sets the return value 4300 ** of the application-defined function to be the 64-bit signed integer 4301 ** value given in the 2nd argument. 4302 ** 4303 ** ^The sqlite3_result_null() interface sets the return value 4304 ** of the application-defined function to be NULL. 4305 ** 4306 ** ^The sqlite3_result_text(), sqlite3_result_text16(), 4307 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4308 ** set the return value of the application-defined function to be 4309 ** a text string which is represented as UTF-8, UTF-16 native byte order, 4310 ** UTF-16 little endian, or UTF-16 big endian, respectively. 4311 ** ^SQLite takes the text result from the application from 4312 ** the 2nd parameter of the sqlite3_result_text* interfaces. 4313 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4314 ** is negative, then SQLite takes result text from the 2nd parameter 4315 ** through the first zero character. 4316 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4317 ** is non-negative, then as many bytes (not characters) of the text 4318 ** pointed to by the 2nd parameter are taken as the application-defined 4319 ** function result. If the 3rd parameter is non-negative, then it 4320 ** must be the byte offset into the string where the NUL terminator would 4321 ** appear if the string where NUL terminated. If any NUL characters occur 4322 ** in the string at a byte offset that is less than the value of the 3rd 4323 ** parameter, then the resulting string will contain embedded NULs and the 4324 ** result of expressions operating on strings with embedded NULs is undefined. 4325 ** ^If the 4th parameter to the sqlite3_result_text* interfaces 4326 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4327 ** function as the destructor on the text or BLOB result when it has 4328 ** finished using that result. 4329 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4330 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4331 ** assumes that the text or BLOB result is in constant space and does not 4332 ** copy the content of the parameter nor call a destructor on the content 4333 ** when it has finished using that result. 4334 ** ^If the 4th parameter to the sqlite3_result_text* interfaces 4335 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4336 ** then SQLite makes a copy of the result into space obtained from 4337 ** from [sqlite3_malloc()] before it returns. 4338 ** 4339 ** ^The sqlite3_result_value() interface sets the result of 4340 ** the application-defined function to be a copy the 4341 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4342 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4343 ** so that the [sqlite3_value] specified in the parameter may change or 4344 ** be deallocated after sqlite3_result_value() returns without harm. 4345 ** ^A [protected sqlite3_value] object may always be used where an 4346 ** [unprotected sqlite3_value] object is required, so either 4347 ** kind of [sqlite3_value] object can be used with this interface. 4348 ** 4349 ** If these routines are called from within the different thread 4350 ** than the one containing the application-defined function that received 4351 ** the [sqlite3_context] pointer, the results are undefined. 4352 */ 4353 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4354 SQLITE_API void sqlite3_result_double(sqlite3_context*, double); 4355 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int); 4356 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int); 4357 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*); 4358 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*); 4359 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int); 4360 SQLITE_API void sqlite3_result_int(sqlite3_context*, int); 4361 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4362 SQLITE_API void sqlite3_result_null(sqlite3_context*); 4363 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4364 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4365 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4366 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4367 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4368 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n); 4369 4370 /* 4371 ** CAPI3REF: Define New Collating Sequences 4372 ** 4373 ** ^These functions add, remove, or modify a [collation] associated 4374 ** with the [database connection] specified as the first argument. 4375 ** 4376 ** ^The name of the collation is a UTF-8 string 4377 ** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4378 ** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4379 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4380 ** considered to be the same name. 4381 ** 4382 ** ^(The third argument (eTextRep) must be one of the constants: 4383 ** <ul> 4384 ** <li> [SQLITE_UTF8], 4385 ** <li> [SQLITE_UTF16LE], 4386 ** <li> [SQLITE_UTF16BE], 4387 ** <li> [SQLITE_UTF16], or 4388 ** <li> [SQLITE_UTF16_ALIGNED]. 4389 ** </ul>)^ 4390 ** ^The eTextRep argument determines the encoding of strings passed 4391 ** to the collating function callback, xCallback. 4392 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4393 ** force strings to be UTF16 with native byte order. 4394 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4395 ** on an even byte address. 4396 ** 4397 ** ^The fourth argument, pArg, is an application data pointer that is passed 4398 ** through as the first argument to the collating function callback. 4399 ** 4400 ** ^The fifth argument, xCallback, is a pointer to the collating function. 4401 ** ^Multiple collating functions can be registered using the same name but 4402 ** with different eTextRep parameters and SQLite will use whichever 4403 ** function requires the least amount of data transformation. 4404 ** ^If the xCallback argument is NULL then the collating function is 4405 ** deleted. ^When all collating functions having the same name are deleted, 4406 ** that collation is no longer usable. 4407 ** 4408 ** ^The collating function callback is invoked with a copy of the pArg 4409 ** application data pointer and with two strings in the encoding specified 4410 ** by the eTextRep argument. The collating function must return an 4411 ** integer that is negative, zero, or positive 4412 ** if the first string is less than, equal to, or greater than the second, 4413 ** respectively. A collating function must always return the same answer 4414 ** given the same inputs. If two or more collating functions are registered 4415 ** to the same collation name (using different eTextRep values) then all 4416 ** must give an equivalent answer when invoked with equivalent strings. 4417 ** The collating function must obey the following properties for all 4418 ** strings A, B, and C: 4419 ** 4420 ** <ol> 4421 ** <li> If A==B then B==A. 4422 ** <li> If A==B and B==C then A==C. 4423 ** <li> If A<B THEN B>A. 4424 ** <li> If A<B and B<C then A<C. 4425 ** </ol> 4426 ** 4427 ** If a collating function fails any of the above constraints and that 4428 ** collating function is registered and used, then the behavior of SQLite 4429 ** is undefined. 4430 ** 4431 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4432 ** with the addition that the xDestroy callback is invoked on pArg when 4433 ** the collating function is deleted. 4434 ** ^Collating functions are deleted when they are overridden by later 4435 ** calls to the collation creation functions or when the 4436 ** [database connection] is closed using [sqlite3_close()]. 4437 ** 4438 ** ^The xDestroy callback is <u>not</u> called if the 4439 ** sqlite3_create_collation_v2() function fails. Applications that invoke 4440 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4441 ** check the return code and dispose of the application data pointer 4442 ** themselves rather than expecting SQLite to deal with it for them. 4443 ** This is different from every other SQLite interface. The inconsistency 4444 ** is unfortunate but cannot be changed without breaking backwards 4445 ** compatibility. 4446 ** 4447 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4448 */ 4449 SQLITE_API int sqlite3_create_collation( 4450 sqlite3*, 4451 const char *zName, 4452 int eTextRep, 4453 void *pArg, 4454 int(*xCompare)(void*,int,const void*,int,const void*) 4455 ); 4456 SQLITE_API int sqlite3_create_collation_v2( 4457 sqlite3*, 4458 const char *zName, 4459 int eTextRep, 4460 void *pArg, 4461 int(*xCompare)(void*,int,const void*,int,const void*), 4462 void(*xDestroy)(void*) 4463 ); 4464 SQLITE_API int sqlite3_create_collation16( 4465 sqlite3*, 4466 const void *zName, 4467 int eTextRep, 4468 void *pArg, 4469 int(*xCompare)(void*,int,const void*,int,const void*) 4470 ); 4471 4472 /* 4473 ** CAPI3REF: Collation Needed Callbacks 4474 ** 4475 ** ^To avoid having to register all collation sequences before a database 4476 ** can be used, a single callback function may be registered with the 4477 ** [database connection] to be invoked whenever an undefined collation 4478 ** sequence is required. 4479 ** 4480 ** ^If the function is registered using the sqlite3_collation_needed() API, 4481 ** then it is passed the names of undefined collation sequences as strings 4482 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4483 ** the names are passed as UTF-16 in machine native byte order. 4484 ** ^A call to either function replaces the existing collation-needed callback. 4485 ** 4486 ** ^(When the callback is invoked, the first argument passed is a copy 4487 ** of the second argument to sqlite3_collation_needed() or 4488 ** sqlite3_collation_needed16(). The second argument is the database 4489 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4490 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4491 ** sequence function required. The fourth parameter is the name of the 4492 ** required collation sequence.)^ 4493 ** 4494 ** The callback function should register the desired collation using 4495 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4496 ** [sqlite3_create_collation_v2()]. 4497 */ 4498 SQLITE_API int sqlite3_collation_needed( 4499 sqlite3*, 4500 void*, 4501 void(*)(void*,sqlite3*,int eTextRep,const char*) 4502 ); 4503 SQLITE_API int sqlite3_collation_needed16( 4504 sqlite3*, 4505 void*, 4506 void(*)(void*,sqlite3*,int eTextRep,const void*) 4507 ); 4508 4509 #ifdef SQLITE_HAS_CODEC 4510 /* 4511 ** Specify the key for an encrypted database. This routine should be 4512 ** called right after sqlite3_open(). 4513 ** 4514 ** The code to implement this API is not available in the public release 4515 ** of SQLite. 4516 */ 4517 SQLITE_API int sqlite3_key( 4518 sqlite3 *db, /* Database to be rekeyed */ 4519 const void *pKey, int nKey /* The key */ 4520 ); 4521 4522 /* 4523 ** Change the key on an open database. If the current database is not 4524 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4525 ** database is decrypted. 4526 ** 4527 ** The code to implement this API is not available in the public release 4528 ** of SQLite. 4529 */ 4530 SQLITE_API int sqlite3_rekey( 4531 sqlite3 *db, /* Database to be rekeyed */ 4532 const void *pKey, int nKey /* The new key */ 4533 ); 4534 4535 /* 4536 ** Specify the activation key for a SEE database. Unless 4537 ** activated, none of the SEE routines will work. 4538 */ 4539 SQLITE_API void sqlite3_activate_see( 4540 const char *zPassPhrase /* Activation phrase */ 4541 ); 4542 #endif 4543 4544 #ifdef SQLITE_ENABLE_CEROD 4545 /* 4546 ** Specify the activation key for a CEROD database. Unless 4547 ** activated, none of the CEROD routines will work. 4548 */ 4549 SQLITE_API void sqlite3_activate_cerod( 4550 const char *zPassPhrase /* Activation phrase */ 4551 ); 4552 #endif 4553 4554 /* 4555 ** CAPI3REF: Suspend Execution For A Short Time 4556 ** 4557 ** The sqlite3_sleep() function causes the current thread to suspend execution 4558 ** for at least a number of milliseconds specified in its parameter. 4559 ** 4560 ** If the operating system does not support sleep requests with 4561 ** millisecond time resolution, then the time will be rounded up to 4562 ** the nearest second. The number of milliseconds of sleep actually 4563 ** requested from the operating system is returned. 4564 ** 4565 ** ^SQLite implements this interface by calling the xSleep() 4566 ** method of the default [sqlite3_vfs] object. If the xSleep() method 4567 ** of the default VFS is not implemented correctly, or not implemented at 4568 ** all, then the behavior of sqlite3_sleep() may deviate from the description 4569 ** in the previous paragraphs. 4570 */ 4571 SQLITE_API int sqlite3_sleep(int); 4572 4573 /* 4574 ** CAPI3REF: Name Of The Folder Holding Temporary Files 4575 ** 4576 ** ^(If this global variable is made to point to a string which is 4577 ** the name of a folder (a.k.a. directory), then all temporary files 4578 ** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4579 ** will be placed in that directory.)^ ^If this variable 4580 ** is a NULL pointer, then SQLite performs a search for an appropriate 4581 ** temporary file directory. 4582 ** 4583 ** It is not safe to read or modify this variable in more than one 4584 ** thread at a time. It is not safe to read or modify this variable 4585 ** if a [database connection] is being used at the same time in a separate 4586 ** thread. 4587 ** It is intended that this variable be set once 4588 ** as part of process initialization and before any SQLite interface 4589 ** routines have been called and that this variable remain unchanged 4590 ** thereafter. 4591 ** 4592 ** ^The [temp_store_directory pragma] may modify this variable and cause 4593 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4594 ** the [temp_store_directory pragma] always assumes that any string 4595 ** that this variable points to is held in memory obtained from 4596 ** [sqlite3_malloc] and the pragma may attempt to free that memory 4597 ** using [sqlite3_free]. 4598 ** Hence, if this variable is modified directly, either it should be 4599 ** made NULL or made to point to memory obtained from [sqlite3_malloc] 4600 ** or else the use of the [temp_store_directory pragma] should be avoided. 4601 ** 4602 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set 4603 ** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 4604 ** features that require the use of temporary files may fail. Here is an 4605 ** example of how to do this using C++ with the Windows Runtime: 4606 ** 4607 ** <blockquote><pre> 4608 ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 4609 ** TemporaryFolder->Path->Data(); 4610 ** char zPathBuf[MAX_PATH + 1]; 4611 ** memset(zPathBuf, 0, sizeof(zPathBuf)); 4612 ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 4613 ** NULL, NULL); 4614 ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 4615 ** </pre></blockquote> 4616 */ 4617 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory; 4618 4619 /* 4620 ** CAPI3REF: Name Of The Folder Holding Database Files 4621 ** 4622 ** ^(If this global variable is made to point to a string which is 4623 ** the name of a folder (a.k.a. directory), then all database files 4624 ** specified with a relative pathname and created or accessed by 4625 ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 4626 ** to be relative to that directory.)^ ^If this variable is a NULL 4627 ** pointer, then SQLite assumes that all database files specified 4628 ** with a relative pathname are relative to the current directory 4629 ** for the process. Only the windows VFS makes use of this global 4630 ** variable; it is ignored by the unix VFS. 4631 ** 4632 ** Changing the value of this variable while a database connection is 4633 ** open can result in a corrupt database. 4634 ** 4635 ** It is not safe to read or modify this variable in more than one 4636 ** thread at a time. It is not safe to read or modify this variable 4637 ** if a [database connection] is being used at the same time in a separate 4638 ** thread. 4639 ** It is intended that this variable be set once 4640 ** as part of process initialization and before any SQLite interface 4641 ** routines have been called and that this variable remain unchanged 4642 ** thereafter. 4643 ** 4644 ** ^The [data_store_directory pragma] may modify this variable and cause 4645 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4646 ** the [data_store_directory pragma] always assumes that any string 4647 ** that this variable points to is held in memory obtained from 4648 ** [sqlite3_malloc] and the pragma may attempt to free that memory 4649 ** using [sqlite3_free]. 4650 ** Hence, if this variable is modified directly, either it should be 4651 ** made NULL or made to point to memory obtained from [sqlite3_malloc] 4652 ** or else the use of the [data_store_directory pragma] should be avoided. 4653 */ 4654 SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory; 4655 4656 /* 4657 ** CAPI3REF: Test For Auto-Commit Mode 4658 ** KEYWORDS: {autocommit mode} 4659 ** 4660 ** ^The sqlite3_get_autocommit() interface returns non-zero or 4661 ** zero if the given database connection is or is not in autocommit mode, 4662 ** respectively. ^Autocommit mode is on by default. 4663 ** ^Autocommit mode is disabled by a [BEGIN] statement. 4664 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 4665 ** 4666 ** If certain kinds of errors occur on a statement within a multi-statement 4667 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 4668 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 4669 ** transaction might be rolled back automatically. The only way to 4670 ** find out whether SQLite automatically rolled back the transaction after 4671 ** an error is to use this function. 4672 ** 4673 ** If another thread changes the autocommit status of the database 4674 ** connection while this routine is running, then the return value 4675 ** is undefined. 4676 */ 4677 SQLITE_API int sqlite3_get_autocommit(sqlite3*); 4678 4679 /* 4680 ** CAPI3REF: Find The Database Handle Of A Prepared Statement 4681 ** 4682 ** ^The sqlite3_db_handle interface returns the [database connection] handle 4683 ** to which a [prepared statement] belongs. ^The [database connection] 4684 ** returned by sqlite3_db_handle is the same [database connection] 4685 ** that was the first argument 4686 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 4687 ** create the statement in the first place. 4688 */ 4689 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 4690 4691 /* 4692 ** CAPI3REF: Return The Filename For A Database Connection 4693 ** 4694 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 4695 ** associated with database N of connection D. ^The main database file 4696 ** has the name "main". If there is no attached database N on the database 4697 ** connection D, or if database N is a temporary or in-memory database, then 4698 ** a NULL pointer is returned. 4699 ** 4700 ** ^The filename returned by this function is the output of the 4701 ** xFullPathname method of the [VFS]. ^In other words, the filename 4702 ** will be an absolute pathname, even if the filename used 4703 ** to open the database originally was a URI or relative pathname. 4704 */ 4705 SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 4706 4707 /* 4708 ** CAPI3REF: Determine if a database is read-only 4709 ** 4710 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 4711 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not 4712 ** the name of a database on connection D. 4713 */ 4714 SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 4715 4716 /* 4717 ** CAPI3REF: Find the next prepared statement 4718 ** 4719 ** ^This interface returns a pointer to the next [prepared statement] after 4720 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 4721 ** then this interface returns a pointer to the first prepared statement 4722 ** associated with the database connection pDb. ^If no prepared statement 4723 ** satisfies the conditions of this routine, it returns NULL. 4724 ** 4725 ** The [database connection] pointer D in a call to 4726 ** [sqlite3_next_stmt(D,S)] must refer to an open database 4727 ** connection and in particular must not be a NULL pointer. 4728 */ 4729 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 4730 4731 /* 4732 ** CAPI3REF: Commit And Rollback Notification Callbacks 4733 ** 4734 ** ^The sqlite3_commit_hook() interface registers a callback 4735 ** function to be invoked whenever a transaction is [COMMIT | committed]. 4736 ** ^Any callback set by a previous call to sqlite3_commit_hook() 4737 ** for the same database connection is overridden. 4738 ** ^The sqlite3_rollback_hook() interface registers a callback 4739 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 4740 ** ^Any callback set by a previous call to sqlite3_rollback_hook() 4741 ** for the same database connection is overridden. 4742 ** ^The pArg argument is passed through to the callback. 4743 ** ^If the callback on a commit hook function returns non-zero, 4744 ** then the commit is converted into a rollback. 4745 ** 4746 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 4747 ** return the P argument from the previous call of the same function 4748 ** on the same [database connection] D, or NULL for 4749 ** the first call for each function on D. 4750 ** 4751 ** The commit and rollback hook callbacks are not reentrant. 4752 ** The callback implementation must not do anything that will modify 4753 ** the database connection that invoked the callback. Any actions 4754 ** to modify the database connection must be deferred until after the 4755 ** completion of the [sqlite3_step()] call that triggered the commit 4756 ** or rollback hook in the first place. 4757 ** Note that running any other SQL statements, including SELECT statements, 4758 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 4759 ** the database connections for the meaning of "modify" in this paragraph. 4760 ** 4761 ** ^Registering a NULL function disables the callback. 4762 ** 4763 ** ^When the commit hook callback routine returns zero, the [COMMIT] 4764 ** operation is allowed to continue normally. ^If the commit hook 4765 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 4766 ** ^The rollback hook is invoked on a rollback that results from a commit 4767 ** hook returning non-zero, just as it would be with any other rollback. 4768 ** 4769 ** ^For the purposes of this API, a transaction is said to have been 4770 ** rolled back if an explicit "ROLLBACK" statement is executed, or 4771 ** an error or constraint causes an implicit rollback to occur. 4772 ** ^The rollback callback is not invoked if a transaction is 4773 ** automatically rolled back because the database connection is closed. 4774 ** 4775 ** See also the [sqlite3_update_hook()] interface. 4776 */ 4777 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 4778 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 4779 4780 /* 4781 ** CAPI3REF: Data Change Notification Callbacks 4782 ** 4783 ** ^The sqlite3_update_hook() interface registers a callback function 4784 ** with the [database connection] identified by the first argument 4785 ** to be invoked whenever a row is updated, inserted or deleted. 4786 ** ^Any callback set by a previous call to this function 4787 ** for the same database connection is overridden. 4788 ** 4789 ** ^The second argument is a pointer to the function to invoke when a 4790 ** row is updated, inserted or deleted. 4791 ** ^The first argument to the callback is a copy of the third argument 4792 ** to sqlite3_update_hook(). 4793 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 4794 ** or [SQLITE_UPDATE], depending on the operation that caused the callback 4795 ** to be invoked. 4796 ** ^The third and fourth arguments to the callback contain pointers to the 4797 ** database and table name containing the affected row. 4798 ** ^The final callback parameter is the [rowid] of the row. 4799 ** ^In the case of an update, this is the [rowid] after the update takes place. 4800 ** 4801 ** ^(The update hook is not invoked when internal system tables are 4802 ** modified (i.e. sqlite_master and sqlite_sequence).)^ 4803 ** 4804 ** ^In the current implementation, the update hook 4805 ** is not invoked when duplication rows are deleted because of an 4806 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 4807 ** invoked when rows are deleted using the [truncate optimization]. 4808 ** The exceptions defined in this paragraph might change in a future 4809 ** release of SQLite. 4810 ** 4811 ** The update hook implementation must not do anything that will modify 4812 ** the database connection that invoked the update hook. Any actions 4813 ** to modify the database connection must be deferred until after the 4814 ** completion of the [sqlite3_step()] call that triggered the update hook. 4815 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4816 ** database connections for the meaning of "modify" in this paragraph. 4817 ** 4818 ** ^The sqlite3_update_hook(D,C,P) function 4819 ** returns the P argument from the previous call 4820 ** on the same [database connection] D, or NULL for 4821 ** the first call on D. 4822 ** 4823 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4824 ** interfaces. 4825 */ 4826 SQLITE_API void *sqlite3_update_hook( 4827 sqlite3*, 4828 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4829 void* 4830 ); 4831 4832 /* 4833 ** CAPI3REF: Enable Or Disable Shared Pager Cache 4834 ** 4835 ** ^(This routine enables or disables the sharing of the database cache 4836 ** and schema data structures between [database connection | connections] 4837 ** to the same database. Sharing is enabled if the argument is true 4838 ** and disabled if the argument is false.)^ 4839 ** 4840 ** ^Cache sharing is enabled and disabled for an entire process. 4841 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4842 ** sharing was enabled or disabled for each thread separately. 4843 ** 4844 ** ^(The cache sharing mode set by this interface effects all subsequent 4845 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4846 ** Existing database connections continue use the sharing mode 4847 ** that was in effect at the time they were opened.)^ 4848 ** 4849 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4850 ** successfully. An [error code] is returned otherwise.)^ 4851 ** 4852 ** ^Shared cache is disabled by default. But this might change in 4853 ** future releases of SQLite. Applications that care about shared 4854 ** cache setting should set it explicitly. 4855 ** 4856 ** This interface is threadsafe on processors where writing a 4857 ** 32-bit integer is atomic. 4858 ** 4859 ** See Also: [SQLite Shared-Cache Mode] 4860 */ 4861 SQLITE_API int sqlite3_enable_shared_cache(int); 4862 4863 /* 4864 ** CAPI3REF: Attempt To Free Heap Memory 4865 ** 4866 ** ^The sqlite3_release_memory() interface attempts to free N bytes 4867 ** of heap memory by deallocating non-essential memory allocations 4868 ** held by the database library. Memory used to cache database 4869 ** pages to improve performance is an example of non-essential memory. 4870 ** ^sqlite3_release_memory() returns the number of bytes actually freed, 4871 ** which might be more or less than the amount requested. 4872 ** ^The sqlite3_release_memory() routine is a no-op returning zero 4873 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4874 ** 4875 ** See also: [sqlite3_db_release_memory()] 4876 */ 4877 SQLITE_API int sqlite3_release_memory(int); 4878 4879 /* 4880 ** CAPI3REF: Free Memory Used By A Database Connection 4881 ** 4882 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 4883 ** memory as possible from database connection D. Unlike the 4884 ** [sqlite3_release_memory()] interface, this interface is effect even 4885 ** when then [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 4886 ** omitted. 4887 ** 4888 ** See also: [sqlite3_release_memory()] 4889 */ 4890 SQLITE_API int sqlite3_db_release_memory(sqlite3*); 4891 4892 /* 4893 ** CAPI3REF: Impose A Limit On Heap Size 4894 ** 4895 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 4896 ** soft limit on the amount of heap memory that may be allocated by SQLite. 4897 ** ^SQLite strives to keep heap memory utilization below the soft heap 4898 ** limit by reducing the number of pages held in the page cache 4899 ** as heap memory usages approaches the limit. 4900 ** ^The soft heap limit is "soft" because even though SQLite strives to stay 4901 ** below the limit, it will exceed the limit rather than generate 4902 ** an [SQLITE_NOMEM] error. In other words, the soft heap limit 4903 ** is advisory only. 4904 ** 4905 ** ^The return value from sqlite3_soft_heap_limit64() is the size of 4906 ** the soft heap limit prior to the call, or negative in the case of an 4907 ** error. ^If the argument N is negative 4908 ** then no change is made to the soft heap limit. Hence, the current 4909 ** size of the soft heap limit can be determined by invoking 4910 ** sqlite3_soft_heap_limit64() with a negative argument. 4911 ** 4912 ** ^If the argument N is zero then the soft heap limit is disabled. 4913 ** 4914 ** ^(The soft heap limit is not enforced in the current implementation 4915 ** if one or more of following conditions are true: 4916 ** 4917 ** <ul> 4918 ** <li> The soft heap limit is set to zero. 4919 ** <li> Memory accounting is disabled using a combination of the 4920 ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 4921 ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 4922 ** <li> An alternative page cache implementation is specified using 4923 ** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 4924 ** <li> The page cache allocates from its own memory pool supplied 4925 ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 4926 ** from the heap. 4927 ** </ul>)^ 4928 ** 4929 ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 4930 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 4931 ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 4932 ** the soft heap limit is enforced on every memory allocation. Without 4933 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 4934 ** when memory is allocated by the page cache. Testing suggests that because 4935 ** the page cache is the predominate memory user in SQLite, most 4936 ** applications will achieve adequate soft heap limit enforcement without 4937 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4938 ** 4939 ** The circumstances under which SQLite will enforce the soft heap limit may 4940 ** changes in future releases of SQLite. 4941 */ 4942 SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 4943 4944 /* 4945 ** CAPI3REF: Deprecated Soft Heap Limit Interface 4946 ** DEPRECATED 4947 ** 4948 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 4949 ** interface. This routine is provided for historical compatibility 4950 ** only. All new applications should use the 4951 ** [sqlite3_soft_heap_limit64()] interface rather than this one. 4952 */ 4953 SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 4954 4955 4956 /* 4957 ** CAPI3REF: Extract Metadata About A Column Of A Table 4958 ** 4959 ** ^This routine returns metadata about a specific column of a specific 4960 ** database table accessible using the [database connection] handle 4961 ** passed as the first function argument. 4962 ** 4963 ** ^The column is identified by the second, third and fourth parameters to 4964 ** this function. ^The second parameter is either the name of the database 4965 ** (i.e. "main", "temp", or an attached database) containing the specified 4966 ** table or NULL. ^If it is NULL, then all attached databases are searched 4967 ** for the table using the same algorithm used by the database engine to 4968 ** resolve unqualified table references. 4969 ** 4970 ** ^The third and fourth parameters to this function are the table and column 4971 ** name of the desired column, respectively. Neither of these parameters 4972 ** may be NULL. 4973 ** 4974 ** ^Metadata is returned by writing to the memory locations passed as the 5th 4975 ** and subsequent parameters to this function. ^Any of these arguments may be 4976 ** NULL, in which case the corresponding element of metadata is omitted. 4977 ** 4978 ** ^(<blockquote> 4979 ** <table border="1"> 4980 ** <tr><th> Parameter <th> Output<br>Type <th> Description 4981 ** 4982 ** <tr><td> 5th <td> const char* <td> Data type 4983 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4984 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4985 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4986 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4987 ** </table> 4988 ** </blockquote>)^ 4989 ** 4990 ** ^The memory pointed to by the character pointers returned for the 4991 ** declaration type and collation sequence is valid only until the next 4992 ** call to any SQLite API function. 4993 ** 4994 ** ^If the specified table is actually a view, an [error code] is returned. 4995 ** 4996 ** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4997 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4998 ** parameters are set for the explicitly declared column. ^(If there is no 4999 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output 5000 ** parameters are set as follows: 5001 ** 5002 ** <pre> 5003 ** data type: "INTEGER" 5004 ** collation sequence: "BINARY" 5005 ** not null: 0 5006 ** primary key: 1 5007 ** auto increment: 0 5008 ** </pre>)^ 5009 ** 5010 ** ^(This function may load one or more schemas from database files. If an 5011 ** error occurs during this process, or if the requested table or column 5012 ** cannot be found, an [error code] is returned and an error message left 5013 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 5014 ** 5015 ** ^This API is only available if the library was compiled with the 5016 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 5017 */ 5018 SQLITE_API int sqlite3_table_column_metadata( 5019 sqlite3 *db, /* Connection handle */ 5020 const char *zDbName, /* Database name or NULL */ 5021 const char *zTableName, /* Table name */ 5022 const char *zColumnName, /* Column name */ 5023 char const **pzDataType, /* OUTPUT: Declared data type */ 5024 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5025 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5026 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5027 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5028 ); 5029 5030 /* 5031 ** CAPI3REF: Load An Extension 5032 ** 5033 ** ^This interface loads an SQLite extension library from the named file. 5034 ** 5035 ** ^The sqlite3_load_extension() interface attempts to load an 5036 ** [SQLite extension] library contained in the file zFile. If 5037 ** the file cannot be loaded directly, attempts are made to load 5038 ** with various operating-system specific extensions added. 5039 ** So for example, if "samplelib" cannot be loaded, then names like 5040 ** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5041 ** be tried also. 5042 ** 5043 ** ^The entry point is zProc. 5044 ** ^(zProc may be 0, in which case SQLite will try to come up with an 5045 ** entry point name on its own. It first tries "sqlite3_extension_init". 5046 ** If that does not work, it constructs a name "sqlite3_X_init" where the 5047 ** X is consists of the lower-case equivalent of all ASCII alphabetic 5048 ** characters in the filename from the last "/" to the first following 5049 ** "." and omitting any initial "lib".)^ 5050 ** ^The sqlite3_load_extension() interface returns 5051 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5052 ** ^If an error occurs and pzErrMsg is not 0, then the 5053 ** [sqlite3_load_extension()] interface shall attempt to 5054 ** fill *pzErrMsg with error message text stored in memory 5055 ** obtained from [sqlite3_malloc()]. The calling function 5056 ** should free this memory by calling [sqlite3_free()]. 5057 ** 5058 ** ^Extension loading must be enabled using 5059 ** [sqlite3_enable_load_extension()] prior to calling this API, 5060 ** otherwise an error will be returned. 5061 ** 5062 ** See also the [load_extension() SQL function]. 5063 */ 5064 SQLITE_API int sqlite3_load_extension( 5065 sqlite3 *db, /* Load the extension into this database connection */ 5066 const char *zFile, /* Name of the shared library containing extension */ 5067 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5068 char **pzErrMsg /* Put error message here if not 0 */ 5069 ); 5070 5071 /* 5072 ** CAPI3REF: Enable Or Disable Extension Loading 5073 ** 5074 ** ^So as not to open security holes in older applications that are 5075 ** unprepared to deal with [extension loading], and as a means of disabling 5076 ** [extension loading] while evaluating user-entered SQL, the following API 5077 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5078 ** 5079 ** ^Extension loading is off by default. 5080 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5081 ** to turn extension loading on and call it with onoff==0 to turn 5082 ** it back off again. 5083 */ 5084 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5085 5086 /* 5087 ** CAPI3REF: Automatically Load Statically Linked Extensions 5088 ** 5089 ** ^This interface causes the xEntryPoint() function to be invoked for 5090 ** each new [database connection] that is created. The idea here is that 5091 ** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5092 ** that is to be automatically loaded into all new database connections. 5093 ** 5094 ** ^(Even though the function prototype shows that xEntryPoint() takes 5095 ** no arguments and returns void, SQLite invokes xEntryPoint() with three 5096 ** arguments and expects and integer result as if the signature of the 5097 ** entry point where as follows: 5098 ** 5099 ** <blockquote><pre> 5100 ** int xEntryPoint( 5101 ** sqlite3 *db, 5102 ** const char **pzErrMsg, 5103 ** const struct sqlite3_api_routines *pThunk 5104 ** ); 5105 ** </pre></blockquote>)^ 5106 ** 5107 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5108 ** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5109 ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5110 ** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5111 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5112 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5113 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 5114 ** 5115 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 5116 ** on the list of automatic extensions is a harmless no-op. ^No entry point 5117 ** will be called more than once for each database connection that is opened. 5118 ** 5119 ** See also: [sqlite3_reset_auto_extension()]. 5120 */ 5121 SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void)); 5122 5123 /* 5124 ** CAPI3REF: Reset Automatic Extension Loading 5125 ** 5126 ** ^This interface disables all automatic extensions previously 5127 ** registered using [sqlite3_auto_extension()]. 5128 */ 5129 SQLITE_API void sqlite3_reset_auto_extension(void); 5130 5131 /* 5132 ** The interface to the virtual-table mechanism is currently considered 5133 ** to be experimental. The interface might change in incompatible ways. 5134 ** If this is a problem for you, do not use the interface at this time. 5135 ** 5136 ** When the virtual-table mechanism stabilizes, we will declare the 5137 ** interface fixed, support it indefinitely, and remove this comment. 5138 */ 5139 5140 /* 5141 ** Structures used by the virtual table interface 5142 */ 5143 typedef struct sqlite3_vtab sqlite3_vtab; 5144 typedef struct sqlite3_index_info sqlite3_index_info; 5145 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 5146 typedef struct sqlite3_module sqlite3_module; 5147 5148 /* 5149 ** CAPI3REF: Virtual Table Object 5150 ** KEYWORDS: sqlite3_module {virtual table module} 5151 ** 5152 ** This structure, sometimes called a "virtual table module", 5153 ** defines the implementation of a [virtual tables]. 5154 ** This structure consists mostly of methods for the module. 5155 ** 5156 ** ^A virtual table module is created by filling in a persistent 5157 ** instance of this structure and passing a pointer to that instance 5158 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 5159 ** ^The registration remains valid until it is replaced by a different 5160 ** module or until the [database connection] closes. The content 5161 ** of this structure must not change while it is registered with 5162 ** any database connection. 5163 */ 5164 struct sqlite3_module { 5165 int iVersion; 5166 int (*xCreate)(sqlite3*, void *pAux, 5167 int argc, const char *const*argv, 5168 sqlite3_vtab **ppVTab, char**); 5169 int (*xConnect)(sqlite3*, void *pAux, 5170 int argc, const char *const*argv, 5171 sqlite3_vtab **ppVTab, char**); 5172 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 5173 int (*xDisconnect)(sqlite3_vtab *pVTab); 5174 int (*xDestroy)(sqlite3_vtab *pVTab); 5175 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 5176 int (*xClose)(sqlite3_vtab_cursor*); 5177 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 5178 int argc, sqlite3_value **argv); 5179 int (*xNext)(sqlite3_vtab_cursor*); 5180 int (*xEof)(sqlite3_vtab_cursor*); 5181 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 5182 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 5183 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 5184 int (*xBegin)(sqlite3_vtab *pVTab); 5185 int (*xSync)(sqlite3_vtab *pVTab); 5186 int (*xCommit)(sqlite3_vtab *pVTab); 5187 int (*xRollback)(sqlite3_vtab *pVTab); 5188 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 5189 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 5190 void **ppArg); 5191 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 5192 /* The methods above are in version 1 of the sqlite_module object. Those 5193 ** below are for version 2 and greater. */ 5194 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 5195 int (*xRelease)(sqlite3_vtab *pVTab, int); 5196 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 5197 }; 5198 5199 /* 5200 ** CAPI3REF: Virtual Table Indexing Information 5201 ** KEYWORDS: sqlite3_index_info 5202 ** 5203 ** The sqlite3_index_info structure and its substructures is used as part 5204 ** of the [virtual table] interface to 5205 ** pass information into and receive the reply from the [xBestIndex] 5206 ** method of a [virtual table module]. The fields under **Inputs** are the 5207 ** inputs to xBestIndex and are read-only. xBestIndex inserts its 5208 ** results into the **Outputs** fields. 5209 ** 5210 ** ^(The aConstraint[] array records WHERE clause constraints of the form: 5211 ** 5212 ** <blockquote>column OP expr</blockquote> 5213 ** 5214 ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 5215 ** stored in aConstraint[].op using one of the 5216 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 5217 ** ^(The index of the column is stored in 5218 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5219 ** expr on the right-hand side can be evaluated (and thus the constraint 5220 ** is usable) and false if it cannot.)^ 5221 ** 5222 ** ^The optimizer automatically inverts terms of the form "expr OP column" 5223 ** and makes other simplifications to the WHERE clause in an attempt to 5224 ** get as many WHERE clause terms into the form shown above as possible. 5225 ** ^The aConstraint[] array only reports WHERE clause terms that are 5226 ** relevant to the particular virtual table being queried. 5227 ** 5228 ** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5229 ** ^Each term of aOrderBy records a column of the ORDER BY clause. 5230 ** 5231 ** The [xBestIndex] method must fill aConstraintUsage[] with information 5232 ** about what parameters to pass to xFilter. ^If argvIndex>0 then 5233 ** the right-hand side of the corresponding aConstraint[] is evaluated 5234 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5235 ** is true, then the constraint is assumed to be fully handled by the 5236 ** virtual table and is not checked again by SQLite.)^ 5237 ** 5238 ** ^The idxNum and idxPtr values are recorded and passed into the 5239 ** [xFilter] method. 5240 ** ^[sqlite3_free()] is used to free idxPtr if and only if 5241 ** needToFreeIdxPtr is true. 5242 ** 5243 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5244 ** the correct order to satisfy the ORDER BY clause so that no separate 5245 ** sorting step is required. 5246 ** 5247 ** ^The estimatedCost value is an estimate of the cost of doing the 5248 ** particular lookup. A full scan of a table with N entries should have 5249 ** a cost of N. A binary search of a table of N entries should have a 5250 ** cost of approximately log(N). 5251 */ 5252 struct sqlite3_index_info { 5253 /* Inputs */ 5254 int nConstraint; /* Number of entries in aConstraint */ 5255 struct sqlite3_index_constraint { 5256 int iColumn; /* Column on left-hand side of constraint */ 5257 unsigned char op; /* Constraint operator */ 5258 unsigned char usable; /* True if this constraint is usable */ 5259 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5260 } *aConstraint; /* Table of WHERE clause constraints */ 5261 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5262 struct sqlite3_index_orderby { 5263 int iColumn; /* Column number */ 5264 unsigned char desc; /* True for DESC. False for ASC. */ 5265 } *aOrderBy; /* The ORDER BY clause */ 5266 /* Outputs */ 5267 struct sqlite3_index_constraint_usage { 5268 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5269 unsigned char omit; /* Do not code a test for this constraint */ 5270 } *aConstraintUsage; 5271 int idxNum; /* Number used to identify the index */ 5272 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5273 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5274 int orderByConsumed; /* True if output is already ordered */ 5275 double estimatedCost; /* Estimated cost of using this index */ 5276 }; 5277 5278 /* 5279 ** CAPI3REF: Virtual Table Constraint Operator Codes 5280 ** 5281 ** These macros defined the allowed values for the 5282 ** [sqlite3_index_info].aConstraint[].op field. Each value represents 5283 ** an operator that is part of a constraint term in the wHERE clause of 5284 ** a query that uses a [virtual table]. 5285 */ 5286 #define SQLITE_INDEX_CONSTRAINT_EQ 2 5287 #define SQLITE_INDEX_CONSTRAINT_GT 4 5288 #define SQLITE_INDEX_CONSTRAINT_LE 8 5289 #define SQLITE_INDEX_CONSTRAINT_LT 16 5290 #define SQLITE_INDEX_CONSTRAINT_GE 32 5291 #define SQLITE_INDEX_CONSTRAINT_MATCH 64 5292 5293 /* 5294 ** CAPI3REF: Register A Virtual Table Implementation 5295 ** 5296 ** ^These routines are used to register a new [virtual table module] name. 5297 ** ^Module names must be registered before 5298 ** creating a new [virtual table] using the module and before using a 5299 ** preexisting [virtual table] for the module. 5300 ** 5301 ** ^The module name is registered on the [database connection] specified 5302 ** by the first parameter. ^The name of the module is given by the 5303 ** second parameter. ^The third parameter is a pointer to 5304 ** the implementation of the [virtual table module]. ^The fourth 5305 ** parameter is an arbitrary client data pointer that is passed through 5306 ** into the [xCreate] and [xConnect] methods of the virtual table module 5307 ** when a new virtual table is be being created or reinitialized. 5308 ** 5309 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which 5310 ** is a pointer to a destructor for the pClientData. ^SQLite will 5311 ** invoke the destructor function (if it is not NULL) when SQLite 5312 ** no longer needs the pClientData pointer. ^The destructor will also 5313 ** be invoked if the call to sqlite3_create_module_v2() fails. 5314 ** ^The sqlite3_create_module() 5315 ** interface is equivalent to sqlite3_create_module_v2() with a NULL 5316 ** destructor. 5317 */ 5318 SQLITE_API int sqlite3_create_module( 5319 sqlite3 *db, /* SQLite connection to register module with */ 5320 const char *zName, /* Name of the module */ 5321 const sqlite3_module *p, /* Methods for the module */ 5322 void *pClientData /* Client data for xCreate/xConnect */ 5323 ); 5324 SQLITE_API int sqlite3_create_module_v2( 5325 sqlite3 *db, /* SQLite connection to register module with */ 5326 const char *zName, /* Name of the module */ 5327 const sqlite3_module *p, /* Methods for the module */ 5328 void *pClientData, /* Client data for xCreate/xConnect */ 5329 void(*xDestroy)(void*) /* Module destructor function */ 5330 ); 5331 5332 /* 5333 ** CAPI3REF: Virtual Table Instance Object 5334 ** KEYWORDS: sqlite3_vtab 5335 ** 5336 ** Every [virtual table module] implementation uses a subclass 5337 ** of this object to describe a particular instance 5338 ** of the [virtual table]. Each subclass will 5339 ** be tailored to the specific needs of the module implementation. 5340 ** The purpose of this superclass is to define certain fields that are 5341 ** common to all module implementations. 5342 ** 5343 ** ^Virtual tables methods can set an error message by assigning a 5344 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 5345 ** take care that any prior string is freed by a call to [sqlite3_free()] 5346 ** prior to assigning a new string to zErrMsg. ^After the error message 5347 ** is delivered up to the client application, the string will be automatically 5348 ** freed by sqlite3_free() and the zErrMsg field will be zeroed. 5349 */ 5350 struct sqlite3_vtab { 5351 const sqlite3_module *pModule; /* The module for this virtual table */ 5352 int nRef; /* NO LONGER USED */ 5353 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 5354 /* Virtual table implementations will typically add additional fields */ 5355 }; 5356 5357 /* 5358 ** CAPI3REF: Virtual Table Cursor Object 5359 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 5360 ** 5361 ** Every [virtual table module] implementation uses a subclass of the 5362 ** following structure to describe cursors that point into the 5363 ** [virtual table] and are used 5364 ** to loop through the virtual table. Cursors are created using the 5365 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 5366 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used 5367 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 5368 ** of the module. Each module implementation will define 5369 ** the content of a cursor structure to suit its own needs. 5370 ** 5371 ** This superclass exists in order to define fields of the cursor that 5372 ** are common to all implementations. 5373 */ 5374 struct sqlite3_vtab_cursor { 5375 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 5376 /* Virtual table implementations will typically add additional fields */ 5377 }; 5378 5379 /* 5380 ** CAPI3REF: Declare The Schema Of A Virtual Table 5381 ** 5382 ** ^The [xCreate] and [xConnect] methods of a 5383 ** [virtual table module] call this interface 5384 ** to declare the format (the names and datatypes of the columns) of 5385 ** the virtual tables they implement. 5386 */ 5387 SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 5388 5389 /* 5390 ** CAPI3REF: Overload A Function For A Virtual Table 5391 ** 5392 ** ^(Virtual tables can provide alternative implementations of functions 5393 ** using the [xFindFunction] method of the [virtual table module]. 5394 ** But global versions of those functions 5395 ** must exist in order to be overloaded.)^ 5396 ** 5397 ** ^(This API makes sure a global version of a function with a particular 5398 ** name and number of parameters exists. If no such function exists 5399 ** before this API is called, a new function is created.)^ ^The implementation 5400 ** of the new function always causes an exception to be thrown. So 5401 ** the new function is not good for anything by itself. Its only 5402 ** purpose is to be a placeholder function that can be overloaded 5403 ** by a [virtual table]. 5404 */ 5405 SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5406 5407 /* 5408 ** The interface to the virtual-table mechanism defined above (back up 5409 ** to a comment remarkably similar to this one) is currently considered 5410 ** to be experimental. The interface might change in incompatible ways. 5411 ** If this is a problem for you, do not use the interface at this time. 5412 ** 5413 ** When the virtual-table mechanism stabilizes, we will declare the 5414 ** interface fixed, support it indefinitely, and remove this comment. 5415 */ 5416 5417 /* 5418 ** CAPI3REF: A Handle To An Open BLOB 5419 ** KEYWORDS: {BLOB handle} {BLOB handles} 5420 ** 5421 ** An instance of this object represents an open BLOB on which 5422 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5423 ** ^Objects of this type are created by [sqlite3_blob_open()] 5424 ** and destroyed by [sqlite3_blob_close()]. 5425 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5426 ** can be used to read or write small subsections of the BLOB. 5427 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5428 */ 5429 typedef struct sqlite3_blob sqlite3_blob; 5430 5431 /* 5432 ** CAPI3REF: Open A BLOB For Incremental I/O 5433 ** 5434 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5435 ** in row iRow, column zColumn, table zTable in database zDb; 5436 ** in other words, the same BLOB that would be selected by: 5437 ** 5438 ** <pre> 5439 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5440 ** </pre>)^ 5441 ** 5442 ** ^If the flags parameter is non-zero, then the BLOB is opened for read 5443 ** and write access. ^If it is zero, the BLOB is opened for read access. 5444 ** ^It is not possible to open a column that is part of an index or primary 5445 ** key for writing. ^If [foreign key constraints] are enabled, it is 5446 ** not possible to open a column that is part of a [child key] for writing. 5447 ** 5448 ** ^Note that the database name is not the filename that contains 5449 ** the database but rather the symbolic name of the database that 5450 ** appears after the AS keyword when the database is connected using [ATTACH]. 5451 ** ^For the main database file, the database name is "main". 5452 ** ^For TEMP tables, the database name is "temp". 5453 ** 5454 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 5455 ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 5456 ** to be a null pointer.)^ 5457 ** ^This function sets the [database connection] error code and message 5458 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 5459 ** functions. ^Note that the *ppBlob variable is always initialized in a 5460 ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 5461 ** regardless of the success or failure of this routine. 5462 ** 5463 ** ^(If the row that a BLOB handle points to is modified by an 5464 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5465 ** then the BLOB handle is marked as "expired". 5466 ** This is true if any column of the row is changed, even a column 5467 ** other than the one the BLOB handle is open on.)^ 5468 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5469 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5470 ** ^(Changes written into a BLOB prior to the BLOB expiring are not 5471 ** rolled back by the expiration of the BLOB. Such changes will eventually 5472 ** commit if the transaction continues to completion.)^ 5473 ** 5474 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5475 ** the opened blob. ^The size of a blob may not be changed by this 5476 ** interface. Use the [UPDATE] SQL command to change the size of a 5477 ** blob. 5478 ** 5479 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5480 ** and the built-in [zeroblob] SQL function can be used, if desired, 5481 ** to create an empty, zero-filled blob in which to read or write using 5482 ** this interface. 5483 ** 5484 ** To avoid a resource leak, every open [BLOB handle] should eventually 5485 ** be released by a call to [sqlite3_blob_close()]. 5486 */ 5487 SQLITE_API int sqlite3_blob_open( 5488 sqlite3*, 5489 const char *zDb, 5490 const char *zTable, 5491 const char *zColumn, 5492 sqlite3_int64 iRow, 5493 int flags, 5494 sqlite3_blob **ppBlob 5495 ); 5496 5497 /* 5498 ** CAPI3REF: Move a BLOB Handle to a New Row 5499 ** 5500 ** ^This function is used to move an existing blob handle so that it points 5501 ** to a different row of the same database table. ^The new row is identified 5502 ** by the rowid value passed as the second argument. Only the row can be 5503 ** changed. ^The database, table and column on which the blob handle is open 5504 ** remain the same. Moving an existing blob handle to a new row can be 5505 ** faster than closing the existing handle and opening a new one. 5506 ** 5507 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5508 ** it must exist and there must be either a blob or text value stored in 5509 ** the nominated column.)^ ^If the new row is not present in the table, or if 5510 ** it does not contain a blob or text value, or if another error occurs, an 5511 ** SQLite error code is returned and the blob handle is considered aborted. 5512 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5513 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5514 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5515 ** always returns zero. 5516 ** 5517 ** ^This function sets the database handle error code and message. 5518 */ 5519 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5520 5521 /* 5522 ** CAPI3REF: Close A BLOB Handle 5523 ** 5524 ** ^Closes an open [BLOB handle]. 5525 ** 5526 ** ^Closing a BLOB shall cause the current transaction to commit 5527 ** if there are no other BLOBs, no pending prepared statements, and the 5528 ** database connection is in [autocommit mode]. 5529 ** ^If any writes were made to the BLOB, they might be held in cache 5530 ** until the close operation if they will fit. 5531 ** 5532 ** ^(Closing the BLOB often forces the changes 5533 ** out to disk and so if any I/O errors occur, they will likely occur 5534 ** at the time when the BLOB is closed. Any errors that occur during 5535 ** closing are reported as a non-zero return value.)^ 5536 ** 5537 ** ^(The BLOB is closed unconditionally. Even if this routine returns 5538 ** an error code, the BLOB is still closed.)^ 5539 ** 5540 ** ^Calling this routine with a null pointer (such as would be returned 5541 ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 5542 */ 5543 SQLITE_API int sqlite3_blob_close(sqlite3_blob *); 5544 5545 /* 5546 ** CAPI3REF: Return The Size Of An Open BLOB 5547 ** 5548 ** ^Returns the size in bytes of the BLOB accessible via the 5549 ** successfully opened [BLOB handle] in its only argument. ^The 5550 ** incremental blob I/O routines can only read or overwriting existing 5551 ** blob content; they cannot change the size of a blob. 5552 ** 5553 ** This routine only works on a [BLOB handle] which has been created 5554 ** by a prior successful call to [sqlite3_blob_open()] and which has not 5555 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5556 ** to this routine results in undefined and probably undesirable behavior. 5557 */ 5558 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *); 5559 5560 /* 5561 ** CAPI3REF: Read Data From A BLOB Incrementally 5562 ** 5563 ** ^(This function is used to read data from an open [BLOB handle] into a 5564 ** caller-supplied buffer. N bytes of data are copied into buffer Z 5565 ** from the open BLOB, starting at offset iOffset.)^ 5566 ** 5567 ** ^If offset iOffset is less than N bytes from the end of the BLOB, 5568 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 5569 ** less than zero, [SQLITE_ERROR] is returned and no data is read. 5570 ** ^The size of the blob (and hence the maximum value of N+iOffset) 5571 ** can be determined using the [sqlite3_blob_bytes()] interface. 5572 ** 5573 ** ^An attempt to read from an expired [BLOB handle] fails with an 5574 ** error code of [SQLITE_ABORT]. 5575 ** 5576 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 5577 ** Otherwise, an [error code] or an [extended error code] is returned.)^ 5578 ** 5579 ** This routine only works on a [BLOB handle] which has been created 5580 ** by a prior successful call to [sqlite3_blob_open()] and which has not 5581 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5582 ** to this routine results in undefined and probably undesirable behavior. 5583 ** 5584 ** See also: [sqlite3_blob_write()]. 5585 */ 5586 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 5587 5588 /* 5589 ** CAPI3REF: Write Data Into A BLOB Incrementally 5590 ** 5591 ** ^This function is used to write data into an open [BLOB handle] from a 5592 ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 5593 ** into the open BLOB, starting at offset iOffset. 5594 ** 5595 ** ^If the [BLOB handle] passed as the first argument was not opened for 5596 ** writing (the flags parameter to [sqlite3_blob_open()] was zero), 5597 ** this function returns [SQLITE_READONLY]. 5598 ** 5599 ** ^This function may only modify the contents of the BLOB; it is 5600 ** not possible to increase the size of a BLOB using this API. 5601 ** ^If offset iOffset is less than N bytes from the end of the BLOB, 5602 ** [SQLITE_ERROR] is returned and no data is written. ^If N is 5603 ** less than zero [SQLITE_ERROR] is returned and no data is written. 5604 ** The size of the BLOB (and hence the maximum value of N+iOffset) 5605 ** can be determined using the [sqlite3_blob_bytes()] interface. 5606 ** 5607 ** ^An attempt to write to an expired [BLOB handle] fails with an 5608 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 5609 ** before the [BLOB handle] expired are not rolled back by the 5610 ** expiration of the handle, though of course those changes might 5611 ** have been overwritten by the statement that expired the BLOB handle 5612 ** or by other independent statements. 5613 ** 5614 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 5615 ** Otherwise, an [error code] or an [extended error code] is returned.)^ 5616 ** 5617 ** This routine only works on a [BLOB handle] which has been created 5618 ** by a prior successful call to [sqlite3_blob_open()] and which has not 5619 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5620 ** to this routine results in undefined and probably undesirable behavior. 5621 ** 5622 ** See also: [sqlite3_blob_read()]. 5623 */ 5624 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 5625 5626 /* 5627 ** CAPI3REF: Virtual File System Objects 5628 ** 5629 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object 5630 ** that SQLite uses to interact 5631 ** with the underlying operating system. Most SQLite builds come with a 5632 ** single default VFS that is appropriate for the host computer. 5633 ** New VFSes can be registered and existing VFSes can be unregistered. 5634 ** The following interfaces are provided. 5635 ** 5636 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 5637 ** ^Names are case sensitive. 5638 ** ^Names are zero-terminated UTF-8 strings. 5639 ** ^If there is no match, a NULL pointer is returned. 5640 ** ^If zVfsName is NULL then the default VFS is returned. 5641 ** 5642 ** ^New VFSes are registered with sqlite3_vfs_register(). 5643 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 5644 ** ^The same VFS can be registered multiple times without injury. 5645 ** ^To make an existing VFS into the default VFS, register it again 5646 ** with the makeDflt flag set. If two different VFSes with the 5647 ** same name are registered, the behavior is undefined. If a 5648 ** VFS is registered with a name that is NULL or an empty string, 5649 ** then the behavior is undefined. 5650 ** 5651 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 5652 ** ^(If the default VFS is unregistered, another VFS is chosen as 5653 ** the default. The choice for the new VFS is arbitrary.)^ 5654 */ 5655 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 5656 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 5657 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*); 5658 5659 /* 5660 ** CAPI3REF: Mutexes 5661 ** 5662 ** The SQLite core uses these routines for thread 5663 ** synchronization. Though they are intended for internal 5664 ** use by SQLite, code that links against SQLite is 5665 ** permitted to use any of these routines. 5666 ** 5667 ** The SQLite source code contains multiple implementations 5668 ** of these mutex routines. An appropriate implementation 5669 ** is selected automatically at compile-time. ^(The following 5670 ** implementations are available in the SQLite core: 5671 ** 5672 ** <ul> 5673 ** <li> SQLITE_MUTEX_PTHREADS 5674 ** <li> SQLITE_MUTEX_W32 5675 ** <li> SQLITE_MUTEX_NOOP 5676 ** </ul>)^ 5677 ** 5678 ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 5679 ** that does no real locking and is appropriate for use in 5680 ** a single-threaded application. ^The SQLITE_MUTEX_PTHREADS and 5681 ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 5682 ** and Windows. 5683 ** 5684 ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 5685 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 5686 ** implementation is included with the library. In this case the 5687 ** application must supply a custom mutex implementation using the 5688 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 5689 ** before calling sqlite3_initialize() or any other public sqlite3_ 5690 ** function that calls sqlite3_initialize().)^ 5691 ** 5692 ** ^The sqlite3_mutex_alloc() routine allocates a new 5693 ** mutex and returns a pointer to it. ^If it returns NULL 5694 ** that means that a mutex could not be allocated. ^SQLite 5695 ** will unwind its stack and return an error. ^(The argument 5696 ** to sqlite3_mutex_alloc() is one of these integer constants: 5697 ** 5698 ** <ul> 5699 ** <li> SQLITE_MUTEX_FAST 5700 ** <li> SQLITE_MUTEX_RECURSIVE 5701 ** <li> SQLITE_MUTEX_STATIC_MASTER 5702 ** <li> SQLITE_MUTEX_STATIC_MEM 5703 ** <li> SQLITE_MUTEX_STATIC_MEM2 5704 ** <li> SQLITE_MUTEX_STATIC_PRNG 5705 ** <li> SQLITE_MUTEX_STATIC_LRU 5706 ** <li> SQLITE_MUTEX_STATIC_LRU2 5707 ** </ul>)^ 5708 ** 5709 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 5710 ** cause sqlite3_mutex_alloc() to create 5711 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 5712 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 5713 ** The mutex implementation does not need to make a distinction 5714 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 5715 ** not want to. ^SQLite will only request a recursive mutex in 5716 ** cases where it really needs one. ^If a faster non-recursive mutex 5717 ** implementation is available on the host platform, the mutex subsystem 5718 ** might return such a mutex in response to SQLITE_MUTEX_FAST. 5719 ** 5720 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 5721 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 5722 ** a pointer to a static preexisting mutex. ^Six static mutexes are 5723 ** used by the current version of SQLite. Future versions of SQLite 5724 ** may add additional static mutexes. Static mutexes are for internal 5725 ** use by SQLite only. Applications that use SQLite mutexes should 5726 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 5727 ** SQLITE_MUTEX_RECURSIVE. 5728 ** 5729 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 5730 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 5731 ** returns a different mutex on every call. ^But for the static 5732 ** mutex types, the same mutex is returned on every call that has 5733 ** the same type number. 5734 ** 5735 ** ^The sqlite3_mutex_free() routine deallocates a previously 5736 ** allocated dynamic mutex. ^SQLite is careful to deallocate every 5737 ** dynamic mutex that it allocates. The dynamic mutexes must not be in 5738 ** use when they are deallocated. Attempting to deallocate a static 5739 ** mutex results in undefined behavior. ^SQLite never deallocates 5740 ** a static mutex. 5741 ** 5742 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 5743 ** to enter a mutex. ^If another thread is already within the mutex, 5744 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 5745 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 5746 ** upon successful entry. ^(Mutexes created using 5747 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 5748 ** In such cases the, 5749 ** mutex must be exited an equal number of times before another thread 5750 ** can enter.)^ ^(If the same thread tries to enter any other 5751 ** kind of mutex more than once, the behavior is undefined. 5752 ** SQLite will never exhibit 5753 ** such behavior in its own use of mutexes.)^ 5754 ** 5755 ** ^(Some systems (for example, Windows 95) do not support the operation 5756 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 5757 ** will always return SQLITE_BUSY. The SQLite core only ever uses 5758 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 5759 ** 5760 ** ^The sqlite3_mutex_leave() routine exits a mutex that was 5761 ** previously entered by the same thread. ^(The behavior 5762 ** is undefined if the mutex is not currently entered by the 5763 ** calling thread or is not currently allocated. SQLite will 5764 ** never do either.)^ 5765 ** 5766 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 5767 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines 5768 ** behave as no-ops. 5769 ** 5770 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 5771 */ 5772 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int); 5773 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*); 5774 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*); 5775 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*); 5776 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*); 5777 5778 /* 5779 ** CAPI3REF: Mutex Methods Object 5780 ** 5781 ** An instance of this structure defines the low-level routines 5782 ** used to allocate and use mutexes. 5783 ** 5784 ** Usually, the default mutex implementations provided by SQLite are 5785 ** sufficient, however the user has the option of substituting a custom 5786 ** implementation for specialized deployments or systems for which SQLite 5787 ** does not provide a suitable implementation. In this case, the user 5788 ** creates and populates an instance of this structure to pass 5789 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 5790 ** Additionally, an instance of this structure can be used as an 5791 ** output variable when querying the system for the current mutex 5792 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 5793 ** 5794 ** ^The xMutexInit method defined by this structure is invoked as 5795 ** part of system initialization by the sqlite3_initialize() function. 5796 ** ^The xMutexInit routine is called by SQLite exactly once for each 5797 ** effective call to [sqlite3_initialize()]. 5798 ** 5799 ** ^The xMutexEnd method defined by this structure is invoked as 5800 ** part of system shutdown by the sqlite3_shutdown() function. The 5801 ** implementation of this method is expected to release all outstanding 5802 ** resources obtained by the mutex methods implementation, especially 5803 ** those obtained by the xMutexInit method. ^The xMutexEnd() 5804 ** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 5805 ** 5806 ** ^(The remaining seven methods defined by this structure (xMutexAlloc, 5807 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 5808 ** xMutexNotheld) implement the following interfaces (respectively): 5809 ** 5810 ** <ul> 5811 ** <li> [sqlite3_mutex_alloc()] </li> 5812 ** <li> [sqlite3_mutex_free()] </li> 5813 ** <li> [sqlite3_mutex_enter()] </li> 5814 ** <li> [sqlite3_mutex_try()] </li> 5815 ** <li> [sqlite3_mutex_leave()] </li> 5816 ** <li> [sqlite3_mutex_held()] </li> 5817 ** <li> [sqlite3_mutex_notheld()] </li> 5818 ** </ul>)^ 5819 ** 5820 ** The only difference is that the public sqlite3_XXX functions enumerated 5821 ** above silently ignore any invocations that pass a NULL pointer instead 5822 ** of a valid mutex handle. The implementations of the methods defined 5823 ** by this structure are not required to handle this case, the results 5824 ** of passing a NULL pointer instead of a valid mutex handle are undefined 5825 ** (i.e. it is acceptable to provide an implementation that segfaults if 5826 ** it is passed a NULL pointer). 5827 ** 5828 ** The xMutexInit() method must be threadsafe. ^It must be harmless to 5829 ** invoke xMutexInit() multiple times within the same process and without 5830 ** intervening calls to xMutexEnd(). Second and subsequent calls to 5831 ** xMutexInit() must be no-ops. 5832 ** 5833 ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 5834 ** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 5835 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 5836 ** memory allocation for a fast or recursive mutex. 5837 ** 5838 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 5839 ** called, but only if the prior call to xMutexInit returned SQLITE_OK. 5840 ** If xMutexInit fails in any way, it is expected to clean up after itself 5841 ** prior to returning. 5842 */ 5843 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 5844 struct sqlite3_mutex_methods { 5845 int (*xMutexInit)(void); 5846 int (*xMutexEnd)(void); 5847 sqlite3_mutex *(*xMutexAlloc)(int); 5848 void (*xMutexFree)(sqlite3_mutex *); 5849 void (*xMutexEnter)(sqlite3_mutex *); 5850 int (*xMutexTry)(sqlite3_mutex *); 5851 void (*xMutexLeave)(sqlite3_mutex *); 5852 int (*xMutexHeld)(sqlite3_mutex *); 5853 int (*xMutexNotheld)(sqlite3_mutex *); 5854 }; 5855 5856 /* 5857 ** CAPI3REF: Mutex Verification Routines 5858 ** 5859 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 5860 ** are intended for use inside assert() statements. ^The SQLite core 5861 ** never uses these routines except inside an assert() and applications 5862 ** are advised to follow the lead of the core. ^The SQLite core only 5863 ** provides implementations for these routines when it is compiled 5864 ** with the SQLITE_DEBUG flag. ^External mutex implementations 5865 ** are only required to provide these routines if SQLITE_DEBUG is 5866 ** defined and if NDEBUG is not defined. 5867 ** 5868 ** ^These routines should return true if the mutex in their argument 5869 ** is held or not held, respectively, by the calling thread. 5870 ** 5871 ** ^The implementation is not required to provide versions of these 5872 ** routines that actually work. If the implementation does not provide working 5873 ** versions of these routines, it should at least provide stubs that always 5874 ** return true so that one does not get spurious assertion failures. 5875 ** 5876 ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 5877 ** the routine should return 1. This seems counter-intuitive since 5878 ** clearly the mutex cannot be held if it does not exist. But 5879 ** the reason the mutex does not exist is because the build is not 5880 ** using mutexes. And we do not want the assert() containing the 5881 ** call to sqlite3_mutex_held() to fail, so a non-zero return is 5882 ** the appropriate thing to do. ^The sqlite3_mutex_notheld() 5883 ** interface should also return 1 when given a NULL pointer. 5884 */ 5885 #ifndef NDEBUG 5886 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*); 5887 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*); 5888 #endif 5889 5890 /* 5891 ** CAPI3REF: Mutex Types 5892 ** 5893 ** The [sqlite3_mutex_alloc()] interface takes a single argument 5894 ** which is one of these integer constants. 5895 ** 5896 ** The set of static mutexes may change from one SQLite release to the 5897 ** next. Applications that override the built-in mutex logic must be 5898 ** prepared to accommodate additional static mutexes. 5899 */ 5900 #define SQLITE_MUTEX_FAST 0 5901 #define SQLITE_MUTEX_RECURSIVE 1 5902 #define SQLITE_MUTEX_STATIC_MASTER 2 5903 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 5904 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 5905 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 5906 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 5907 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 5908 #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 5909 #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 5910 5911 /* 5912 ** CAPI3REF: Retrieve the mutex for a database connection 5913 ** 5914 ** ^This interface returns a pointer the [sqlite3_mutex] object that 5915 ** serializes access to the [database connection] given in the argument 5916 ** when the [threading mode] is Serialized. 5917 ** ^If the [threading mode] is Single-thread or Multi-thread then this 5918 ** routine returns a NULL pointer. 5919 */ 5920 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 5921 5922 /* 5923 ** CAPI3REF: Low-Level Control Of Database Files 5924 ** 5925 ** ^The [sqlite3_file_control()] interface makes a direct call to the 5926 ** xFileControl method for the [sqlite3_io_methods] object associated 5927 ** with a particular database identified by the second argument. ^The 5928 ** name of the database is "main" for the main database or "temp" for the 5929 ** TEMP database, or the name that appears after the AS keyword for 5930 ** databases that are added using the [ATTACH] SQL command. 5931 ** ^A NULL pointer can be used in place of "main" to refer to the 5932 ** main database file. 5933 ** ^The third and fourth parameters to this routine 5934 ** are passed directly through to the second and third parameters of 5935 ** the xFileControl method. ^The return value of the xFileControl 5936 ** method becomes the return value of this routine. 5937 ** 5938 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 5939 ** a pointer to the underlying [sqlite3_file] object to be written into 5940 ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 5941 ** case is a short-circuit path which does not actually invoke the 5942 ** underlying sqlite3_io_methods.xFileControl method. 5943 ** 5944 ** ^If the second parameter (zDbName) does not match the name of any 5945 ** open database file, then SQLITE_ERROR is returned. ^This error 5946 ** code is not remembered and will not be recalled by [sqlite3_errcode()] 5947 ** or [sqlite3_errmsg()]. The underlying xFileControl method might 5948 ** also return SQLITE_ERROR. There is no way to distinguish between 5949 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5950 ** xFileControl method. 5951 ** 5952 ** See also: [SQLITE_FCNTL_LOCKSTATE] 5953 */ 5954 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5955 5956 /* 5957 ** CAPI3REF: Testing Interface 5958 ** 5959 ** ^The sqlite3_test_control() interface is used to read out internal 5960 ** state of SQLite and to inject faults into SQLite for testing 5961 ** purposes. ^The first parameter is an operation code that determines 5962 ** the number, meaning, and operation of all subsequent parameters. 5963 ** 5964 ** This interface is not for use by applications. It exists solely 5965 ** for verifying the correct operation of the SQLite library. Depending 5966 ** on how the SQLite library is compiled, this interface might not exist. 5967 ** 5968 ** The details of the operation codes, their meanings, the parameters 5969 ** they take, and what they do are all subject to change without notice. 5970 ** Unlike most of the SQLite API, this function is not guaranteed to 5971 ** operate consistently from one release to the next. 5972 */ 5973 SQLITE_API int sqlite3_test_control(int op, ...); 5974 5975 /* 5976 ** CAPI3REF: Testing Interface Operation Codes 5977 ** 5978 ** These constants are the valid operation code parameters used 5979 ** as the first argument to [sqlite3_test_control()]. 5980 ** 5981 ** These parameters and their meanings are subject to change 5982 ** without notice. These values are for testing purposes only. 5983 ** Applications should not use any of these parameters or the 5984 ** [sqlite3_test_control()] interface. 5985 */ 5986 #define SQLITE_TESTCTRL_FIRST 5 5987 #define SQLITE_TESTCTRL_PRNG_SAVE 5 5988 #define SQLITE_TESTCTRL_PRNG_RESTORE 6 5989 #define SQLITE_TESTCTRL_PRNG_RESET 7 5990 #define SQLITE_TESTCTRL_BITVEC_TEST 8 5991 #define SQLITE_TESTCTRL_FAULT_INSTALL 9 5992 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5993 #define SQLITE_TESTCTRL_PENDING_BYTE 11 5994 #define SQLITE_TESTCTRL_ASSERT 12 5995 #define SQLITE_TESTCTRL_ALWAYS 13 5996 #define SQLITE_TESTCTRL_RESERVE 14 5997 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15 5998 #define SQLITE_TESTCTRL_ISKEYWORD 16 5999 #define SQLITE_TESTCTRL_SCRATCHMALLOC 17 6000 #define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 6001 #define SQLITE_TESTCTRL_EXPLAIN_STMT 19 6002 #define SQLITE_TESTCTRL_LAST 19 6003 6004 /* 6005 ** CAPI3REF: SQLite Runtime Status 6006 ** 6007 ** ^This interface is used to retrieve runtime status information 6008 ** about the performance of SQLite, and optionally to reset various 6009 ** highwater marks. ^The first argument is an integer code for 6010 ** the specific parameter to measure. ^(Recognized integer codes 6011 ** are of the form [status parameters | SQLITE_STATUS_...].)^ 6012 ** ^The current value of the parameter is returned into *pCurrent. 6013 ** ^The highest recorded value is returned in *pHighwater. ^If the 6014 ** resetFlag is true, then the highest record value is reset after 6015 ** *pHighwater is written. ^(Some parameters do not record the highest 6016 ** value. For those parameters 6017 ** nothing is written into *pHighwater and the resetFlag is ignored.)^ 6018 ** ^(Other parameters record only the highwater mark and not the current 6019 ** value. For these latter parameters nothing is written into *pCurrent.)^ 6020 ** 6021 ** ^The sqlite3_status() routine returns SQLITE_OK on success and a 6022 ** non-zero [error code] on failure. 6023 ** 6024 ** This routine is threadsafe but is not atomic. This routine can be 6025 ** called while other threads are running the same or different SQLite 6026 ** interfaces. However the values returned in *pCurrent and 6027 ** *pHighwater reflect the status of SQLite at different points in time 6028 ** and it is possible that another thread might change the parameter 6029 ** in between the times when *pCurrent and *pHighwater are written. 6030 ** 6031 ** See also: [sqlite3_db_status()] 6032 */ 6033 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 6034 6035 6036 /* 6037 ** CAPI3REF: Status Parameters 6038 ** KEYWORDS: {status parameters} 6039 ** 6040 ** These integer constants designate various run-time status parameters 6041 ** that can be returned by [sqlite3_status()]. 6042 ** 6043 ** <dl> 6044 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 6045 ** <dd>This parameter is the current amount of memory checked out 6046 ** using [sqlite3_malloc()], either directly or indirectly. The 6047 ** figure includes calls made to [sqlite3_malloc()] by the application 6048 ** and internal memory usage by the SQLite library. Scratch memory 6049 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 6050 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 6051 ** this parameter. The amount returned is the sum of the allocation 6052 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 6053 ** 6054 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 6055 ** <dd>This parameter records the largest memory allocation request 6056 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 6057 ** internal equivalents). Only the value returned in the 6058 ** *pHighwater parameter to [sqlite3_status()] is of interest. 6059 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 6060 ** 6061 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 6062 ** <dd>This parameter records the number of separate memory allocations 6063 ** currently checked out.</dd>)^ 6064 ** 6065 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 6066 ** <dd>This parameter returns the number of pages used out of the 6067 ** [pagecache memory allocator] that was configured using 6068 ** [SQLITE_CONFIG_PAGECACHE]. The 6069 ** value returned is in pages, not in bytes.</dd>)^ 6070 ** 6071 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 6072 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 6073 ** <dd>This parameter returns the number of bytes of page cache 6074 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 6075 ** buffer and where forced to overflow to [sqlite3_malloc()]. The 6076 ** returned value includes allocations that overflowed because they 6077 ** where too large (they were larger than the "sz" parameter to 6078 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 6079 ** no space was left in the page cache.</dd>)^ 6080 ** 6081 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 6082 ** <dd>This parameter records the largest memory allocation request 6083 ** handed to [pagecache memory allocator]. Only the value returned in the 6084 ** *pHighwater parameter to [sqlite3_status()] is of interest. 6085 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 6086 ** 6087 ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 6088 ** <dd>This parameter returns the number of allocations used out of the 6089 ** [scratch memory allocator] configured using 6090 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 6091 ** in bytes. Since a single thread may only have one scratch allocation 6092 ** outstanding at time, this parameter also reports the number of threads 6093 ** using scratch memory at the same time.</dd>)^ 6094 ** 6095 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 6096 ** <dd>This parameter returns the number of bytes of scratch memory 6097 ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 6098 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values 6099 ** returned include overflows because the requested allocation was too 6100 ** larger (that is, because the requested allocation was larger than the 6101 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 6102 ** slots were available. 6103 ** </dd>)^ 6104 ** 6105 ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 6106 ** <dd>This parameter records the largest memory allocation request 6107 ** handed to [scratch memory allocator]. Only the value returned in the 6108 ** *pHighwater parameter to [sqlite3_status()] is of interest. 6109 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 6110 ** 6111 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 6112 ** <dd>This parameter records the deepest parser stack. It is only 6113 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 6114 ** </dl> 6115 ** 6116 ** New status parameters may be added from time to time. 6117 */ 6118 #define SQLITE_STATUS_MEMORY_USED 0 6119 #define SQLITE_STATUS_PAGECACHE_USED 1 6120 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 6121 #define SQLITE_STATUS_SCRATCH_USED 3 6122 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4 6123 #define SQLITE_STATUS_MALLOC_SIZE 5 6124 #define SQLITE_STATUS_PARSER_STACK 6 6125 #define SQLITE_STATUS_PAGECACHE_SIZE 7 6126 #define SQLITE_STATUS_SCRATCH_SIZE 8 6127 #define SQLITE_STATUS_MALLOC_COUNT 9 6128 6129 /* 6130 ** CAPI3REF: Database Connection Status 6131 ** 6132 ** ^This interface is used to retrieve runtime status information 6133 ** about a single [database connection]. ^The first argument is the 6134 ** database connection object to be interrogated. ^The second argument 6135 ** is an integer constant, taken from the set of 6136 ** [SQLITE_DBSTATUS options], that 6137 ** determines the parameter to interrogate. The set of 6138 ** [SQLITE_DBSTATUS options] is likely 6139 ** to grow in future releases of SQLite. 6140 ** 6141 ** ^The current value of the requested parameter is written into *pCur 6142 ** and the highest instantaneous value is written into *pHiwtr. ^If 6143 ** the resetFlg is true, then the highest instantaneous value is 6144 ** reset back down to the current value. 6145 ** 6146 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 6147 ** non-zero [error code] on failure. 6148 ** 6149 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 6150 */ 6151 SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 6152 6153 /* 6154 ** CAPI3REF: Status Parameters for database connections 6155 ** KEYWORDS: {SQLITE_DBSTATUS options} 6156 ** 6157 ** These constants are the available integer "verbs" that can be passed as 6158 ** the second argument to the [sqlite3_db_status()] interface. 6159 ** 6160 ** New verbs may be added in future releases of SQLite. Existing verbs 6161 ** might be discontinued. Applications should check the return code from 6162 ** [sqlite3_db_status()] to make sure that the call worked. 6163 ** The [sqlite3_db_status()] interface will return a non-zero error code 6164 ** if a discontinued or unsupported verb is invoked. 6165 ** 6166 ** <dl> 6167 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 6168 ** <dd>This parameter returns the number of lookaside memory slots currently 6169 ** checked out.</dd>)^ 6170 ** 6171 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 6172 ** <dd>This parameter returns the number malloc attempts that were 6173 ** satisfied using lookaside memory. Only the high-water value is meaningful; 6174 ** the current value is always zero.)^ 6175 ** 6176 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 6177 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 6178 ** <dd>This parameter returns the number malloc attempts that might have 6179 ** been satisfied using lookaside memory but failed due to the amount of 6180 ** memory requested being larger than the lookaside slot size. 6181 ** Only the high-water value is meaningful; 6182 ** the current value is always zero.)^ 6183 ** 6184 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 6185 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 6186 ** <dd>This parameter returns the number malloc attempts that might have 6187 ** been satisfied using lookaside memory but failed due to all lookaside 6188 ** memory already being in use. 6189 ** Only the high-water value is meaningful; 6190 ** the current value is always zero.)^ 6191 ** 6192 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 6193 ** <dd>This parameter returns the approximate number of of bytes of heap 6194 ** memory used by all pager caches associated with the database connection.)^ 6195 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 6196 ** 6197 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 6198 ** <dd>This parameter returns the approximate number of of bytes of heap 6199 ** memory used to store the schema for all databases associated 6200 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 6201 ** ^The full amount of memory used by the schemas is reported, even if the 6202 ** schema memory is shared with other database connections due to 6203 ** [shared cache mode] being enabled. 6204 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 6205 ** 6206 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 6207 ** <dd>This parameter returns the approximate number of of bytes of heap 6208 ** and lookaside memory used by all prepared statements associated with 6209 ** the database connection.)^ 6210 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 6211 ** </dd> 6212 ** 6213 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 6214 ** <dd>This parameter returns the number of pager cache hits that have 6215 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 6216 ** is always 0. 6217 ** </dd> 6218 ** 6219 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6220 ** <dd>This parameter returns the number of pager cache misses that have 6221 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6222 ** is always 0. 6223 ** </dd> 6224 ** 6225 ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 6226 ** <dd>This parameter returns the number of dirty cache entries that have 6227 ** been written to disk. Specifically, the number of pages written to the 6228 ** wal file in wal mode databases, or the number of pages written to the 6229 ** database file in rollback mode databases. Any pages written as part of 6230 ** transaction rollback or database recovery operations are not included. 6231 ** If an IO or other error occurs while writing a page to disk, the effect 6232 ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 6233 ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 6234 ** </dd> 6235 ** </dl> 6236 */ 6237 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6238 #define SQLITE_DBSTATUS_CACHE_USED 1 6239 #define SQLITE_DBSTATUS_SCHEMA_USED 2 6240 #define SQLITE_DBSTATUS_STMT_USED 3 6241 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6242 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6243 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 6244 #define SQLITE_DBSTATUS_CACHE_HIT 7 6245 #define SQLITE_DBSTATUS_CACHE_MISS 8 6246 #define SQLITE_DBSTATUS_CACHE_WRITE 9 6247 #define SQLITE_DBSTATUS_MAX 9 /* Largest defined DBSTATUS */ 6248 6249 6250 /* 6251 ** CAPI3REF: Prepared Statement Status 6252 ** 6253 ** ^(Each prepared statement maintains various 6254 ** [SQLITE_STMTSTATUS counters] that measure the number 6255 ** of times it has performed specific operations.)^ These counters can 6256 ** be used to monitor the performance characteristics of the prepared 6257 ** statements. For example, if the number of table steps greatly exceeds 6258 ** the number of table searches or result rows, that would tend to indicate 6259 ** that the prepared statement is using a full table scan rather than 6260 ** an index. 6261 ** 6262 ** ^(This interface is used to retrieve and reset counter values from 6263 ** a [prepared statement]. The first argument is the prepared statement 6264 ** object to be interrogated. The second argument 6265 ** is an integer code for a specific [SQLITE_STMTSTATUS counter] 6266 ** to be interrogated.)^ 6267 ** ^The current value of the requested counter is returned. 6268 ** ^If the resetFlg is true, then the counter is reset to zero after this 6269 ** interface call returns. 6270 ** 6271 ** See also: [sqlite3_status()] and [sqlite3_db_status()]. 6272 */ 6273 SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 6274 6275 /* 6276 ** CAPI3REF: Status Parameters for prepared statements 6277 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 6278 ** 6279 ** These preprocessor macros define integer codes that name counter 6280 ** values associated with the [sqlite3_stmt_status()] interface. 6281 ** The meanings of the various counters are as follows: 6282 ** 6283 ** <dl> 6284 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 6285 ** <dd>^This is the number of times that SQLite has stepped forward in 6286 ** a table as part of a full table scan. Large numbers for this counter 6287 ** may indicate opportunities for performance improvement through 6288 ** careful use of indices.</dd> 6289 ** 6290 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 6291 ** <dd>^This is the number of sort operations that have occurred. 6292 ** A non-zero value in this counter may indicate an opportunity to 6293 ** improvement performance through careful use of indices.</dd> 6294 ** 6295 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 6296 ** <dd>^This is the number of rows inserted into transient indices that 6297 ** were created automatically in order to help joins run faster. 6298 ** A non-zero value in this counter may indicate an opportunity to 6299 ** improvement performance by adding permanent indices that do not 6300 ** need to be reinitialized each time the statement is run.</dd> 6301 ** </dl> 6302 */ 6303 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 6304 #define SQLITE_STMTSTATUS_SORT 2 6305 #define SQLITE_STMTSTATUS_AUTOINDEX 3 6306 6307 /* 6308 ** CAPI3REF: Custom Page Cache Object 6309 ** 6310 ** The sqlite3_pcache type is opaque. It is implemented by 6311 ** the pluggable module. The SQLite core has no knowledge of 6312 ** its size or internal structure and never deals with the 6313 ** sqlite3_pcache object except by holding and passing pointers 6314 ** to the object. 6315 ** 6316 ** See [sqlite3_pcache_methods2] for additional information. 6317 */ 6318 typedef struct sqlite3_pcache sqlite3_pcache; 6319 6320 /* 6321 ** CAPI3REF: Custom Page Cache Object 6322 ** 6323 ** The sqlite3_pcache_page object represents a single page in the 6324 ** page cache. The page cache will allocate instances of this 6325 ** object. Various methods of the page cache use pointers to instances 6326 ** of this object as parameters or as their return value. 6327 ** 6328 ** See [sqlite3_pcache_methods2] for additional information. 6329 */ 6330 typedef struct sqlite3_pcache_page sqlite3_pcache_page; 6331 struct sqlite3_pcache_page { 6332 void *pBuf; /* The content of the page */ 6333 void *pExtra; /* Extra information associated with the page */ 6334 }; 6335 6336 /* 6337 ** CAPI3REF: Application Defined Page Cache. 6338 ** KEYWORDS: {page cache} 6339 ** 6340 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 6341 ** register an alternative page cache implementation by passing in an 6342 ** instance of the sqlite3_pcache_methods2 structure.)^ 6343 ** In many applications, most of the heap memory allocated by 6344 ** SQLite is used for the page cache. 6345 ** By implementing a 6346 ** custom page cache using this API, an application can better control 6347 ** the amount of memory consumed by SQLite, the way in which 6348 ** that memory is allocated and released, and the policies used to 6349 ** determine exactly which parts of a database file are cached and for 6350 ** how long. 6351 ** 6352 ** The alternative page cache mechanism is an 6353 ** extreme measure that is only needed by the most demanding applications. 6354 ** The built-in page cache is recommended for most uses. 6355 ** 6356 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 6357 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence 6358 ** the application may discard the parameter after the call to 6359 ** [sqlite3_config()] returns.)^ 6360 ** 6361 ** [[the xInit() page cache method]] 6362 ** ^(The xInit() method is called once for each effective 6363 ** call to [sqlite3_initialize()])^ 6364 ** (usually only once during the lifetime of the process). ^(The xInit() 6365 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 6366 ** The intent of the xInit() method is to set up global data structures 6367 ** required by the custom page cache implementation. 6368 ** ^(If the xInit() method is NULL, then the 6369 ** built-in default page cache is used instead of the application defined 6370 ** page cache.)^ 6371 ** 6372 ** [[the xShutdown() page cache method]] 6373 ** ^The xShutdown() method is called by [sqlite3_shutdown()]. 6374 ** It can be used to clean up 6375 ** any outstanding resources before process shutdown, if required. 6376 ** ^The xShutdown() method may be NULL. 6377 ** 6378 ** ^SQLite automatically serializes calls to the xInit method, 6379 ** so the xInit method need not be threadsafe. ^The 6380 ** xShutdown method is only called from [sqlite3_shutdown()] so it does 6381 ** not need to be threadsafe either. All other methods must be threadsafe 6382 ** in multithreaded applications. 6383 ** 6384 ** ^SQLite will never invoke xInit() more than once without an intervening 6385 ** call to xShutdown(). 6386 ** 6387 ** [[the xCreate() page cache methods]] 6388 ** ^SQLite invokes the xCreate() method to construct a new cache instance. 6389 ** SQLite will typically create one cache instance for each open database file, 6390 ** though this is not guaranteed. ^The 6391 ** first parameter, szPage, is the size in bytes of the pages that must 6392 ** be allocated by the cache. ^szPage will always a power of two. ^The 6393 ** second parameter szExtra is a number of bytes of extra storage 6394 ** associated with each page cache entry. ^The szExtra parameter will 6395 ** a number less than 250. SQLite will use the 6396 ** extra szExtra bytes on each page to store metadata about the underlying 6397 ** database page on disk. The value passed into szExtra depends 6398 ** on the SQLite version, the target platform, and how SQLite was compiled. 6399 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being 6400 ** created will be used to cache database pages of a file stored on disk, or 6401 ** false if it is used for an in-memory database. The cache implementation 6402 ** does not have to do anything special based with the value of bPurgeable; 6403 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 6404 ** never invoke xUnpin() except to deliberately delete a page. 6405 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 6406 ** false will always have the "discard" flag set to true. 6407 ** ^Hence, a cache created with bPurgeable false will 6408 ** never contain any unpinned pages. 6409 ** 6410 ** [[the xCachesize() page cache method]] 6411 ** ^(The xCachesize() method may be called at any time by SQLite to set the 6412 ** suggested maximum cache-size (number of pages stored by) the cache 6413 ** instance passed as the first argument. This is the value configured using 6414 ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 6415 ** parameter, the implementation is not required to do anything with this 6416 ** value; it is advisory only. 6417 ** 6418 ** [[the xPagecount() page cache methods]] 6419 ** The xPagecount() method must return the number of pages currently 6420 ** stored in the cache, both pinned and unpinned. 6421 ** 6422 ** [[the xFetch() page cache methods]] 6423 ** The xFetch() method locates a page in the cache and returns a pointer to 6424 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 6425 ** The pBuf element of the returned sqlite3_pcache_page object will be a 6426 ** pointer to a buffer of szPage bytes used to store the content of a 6427 ** single database page. The pExtra element of sqlite3_pcache_page will be 6428 ** a pointer to the szExtra bytes of extra storage that SQLite has requested 6429 ** for each entry in the page cache. 6430 ** 6431 ** The page to be fetched is determined by the key. ^The minimum key value 6432 ** is 1. After it has been retrieved using xFetch, the page is considered 6433 ** to be "pinned". 6434 ** 6435 ** If the requested page is already in the page cache, then the page cache 6436 ** implementation must return a pointer to the page buffer with its content 6437 ** intact. If the requested page is not already in the cache, then the 6438 ** cache implementation should use the value of the createFlag 6439 ** parameter to help it determined what action to take: 6440 ** 6441 ** <table border=1 width=85% align=center> 6442 ** <tr><th> createFlag <th> Behavior when page is not already in cache 6443 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6444 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6445 ** Otherwise return NULL. 6446 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6447 ** NULL if allocating a new page is effectively impossible. 6448 ** </table> 6449 ** 6450 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6451 ** will only use a createFlag of 2 after a prior call with a createFlag of 1 6452 ** failed.)^ In between the to xFetch() calls, SQLite may 6453 ** attempt to unpin one or more cache pages by spilling the content of 6454 ** pinned pages to disk and synching the operating system disk cache. 6455 ** 6456 ** [[the xUnpin() page cache method]] 6457 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6458 ** as its second argument. If the third parameter, discard, is non-zero, 6459 ** then the page must be evicted from the cache. 6460 ** ^If the discard parameter is 6461 ** zero, then the page may be discarded or retained at the discretion of 6462 ** page cache implementation. ^The page cache implementation 6463 ** may choose to evict unpinned pages at any time. 6464 ** 6465 ** The cache must not perform any reference counting. A single 6466 ** call to xUnpin() unpins the page regardless of the number of prior calls 6467 ** to xFetch(). 6468 ** 6469 ** [[the xRekey() page cache methods]] 6470 ** The xRekey() method is used to change the key value associated with the 6471 ** page passed as the second argument. If the cache 6472 ** previously contains an entry associated with newKey, it must be 6473 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6474 ** to be pinned. 6475 ** 6476 ** When SQLite calls the xTruncate() method, the cache must discard all 6477 ** existing cache entries with page numbers (keys) greater than or equal 6478 ** to the value of the iLimit parameter passed to xTruncate(). If any 6479 ** of these pages are pinned, they are implicitly unpinned, meaning that 6480 ** they can be safely discarded. 6481 ** 6482 ** [[the xDestroy() page cache method]] 6483 ** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6484 ** All resources associated with the specified cache should be freed. ^After 6485 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6486 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2 6487 ** functions. 6488 ** 6489 ** [[the xShrink() page cache method]] 6490 ** ^SQLite invokes the xShrink() method when it wants the page cache to 6491 ** free up as much of heap memory as possible. The page cache implementation 6492 ** is not obligated to free any memory, but well-behaved implementations should 6493 ** do their best. 6494 */ 6495 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 6496 struct sqlite3_pcache_methods2 { 6497 int iVersion; 6498 void *pArg; 6499 int (*xInit)(void*); 6500 void (*xShutdown)(void*); 6501 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 6502 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6503 int (*xPagecount)(sqlite3_pcache*); 6504 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6505 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 6506 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 6507 unsigned oldKey, unsigned newKey); 6508 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6509 void (*xDestroy)(sqlite3_pcache*); 6510 void (*xShrink)(sqlite3_pcache*); 6511 }; 6512 6513 /* 6514 ** This is the obsolete pcache_methods object that has now been replaced 6515 ** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 6516 ** retained in the header file for backwards compatibility only. 6517 */ 6518 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 6519 struct sqlite3_pcache_methods { 6520 void *pArg; 6521 int (*xInit)(void*); 6522 void (*xShutdown)(void*); 6523 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 6524 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6525 int (*xPagecount)(sqlite3_pcache*); 6526 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6527 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 6528 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 6529 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6530 void (*xDestroy)(sqlite3_pcache*); 6531 }; 6532 6533 6534 /* 6535 ** CAPI3REF: Online Backup Object 6536 ** 6537 ** The sqlite3_backup object records state information about an ongoing 6538 ** online backup operation. ^The sqlite3_backup object is created by 6539 ** a call to [sqlite3_backup_init()] and is destroyed by a call to 6540 ** [sqlite3_backup_finish()]. 6541 ** 6542 ** See Also: [Using the SQLite Online Backup API] 6543 */ 6544 typedef struct sqlite3_backup sqlite3_backup; 6545 6546 /* 6547 ** CAPI3REF: Online Backup API. 6548 ** 6549 ** The backup API copies the content of one database into another. 6550 ** It is useful either for creating backups of databases or 6551 ** for copying in-memory databases to or from persistent files. 6552 ** 6553 ** See Also: [Using the SQLite Online Backup API] 6554 ** 6555 ** ^SQLite holds a write transaction open on the destination database file 6556 ** for the duration of the backup operation. 6557 ** ^The source database is read-locked only while it is being read; 6558 ** it is not locked continuously for the entire backup operation. 6559 ** ^Thus, the backup may be performed on a live source database without 6560 ** preventing other database connections from 6561 ** reading or writing to the source database while the backup is underway. 6562 ** 6563 ** ^(To perform a backup operation: 6564 ** <ol> 6565 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the 6566 ** backup, 6567 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 6568 ** the data between the two databases, and finally 6569 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources 6570 ** associated with the backup operation. 6571 ** </ol>)^ 6572 ** There should be exactly one call to sqlite3_backup_finish() for each 6573 ** successful call to sqlite3_backup_init(). 6574 ** 6575 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 6576 ** 6577 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 6578 ** [database connection] associated with the destination database 6579 ** and the database name, respectively. 6580 ** ^The database name is "main" for the main database, "temp" for the 6581 ** temporary database, or the name specified after the AS keyword in 6582 ** an [ATTACH] statement for an attached database. 6583 ** ^The S and M arguments passed to 6584 ** sqlite3_backup_init(D,N,S,M) identify the [database connection] 6585 ** and database name of the source database, respectively. 6586 ** ^The source and destination [database connections] (parameters S and D) 6587 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 6588 ** an error. 6589 ** 6590 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 6591 ** returned and an error code and error message are stored in the 6592 ** destination [database connection] D. 6593 ** ^The error code and message for the failed call to sqlite3_backup_init() 6594 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 6595 ** [sqlite3_errmsg16()] functions. 6596 ** ^A successful call to sqlite3_backup_init() returns a pointer to an 6597 ** [sqlite3_backup] object. 6598 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 6599 ** sqlite3_backup_finish() functions to perform the specified backup 6600 ** operation. 6601 ** 6602 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 6603 ** 6604 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 6605 ** the source and destination databases specified by [sqlite3_backup] object B. 6606 ** ^If N is negative, all remaining source pages are copied. 6607 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 6608 ** are still more pages to be copied, then the function returns [SQLITE_OK]. 6609 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 6610 ** from source to destination, then it returns [SQLITE_DONE]. 6611 ** ^If an error occurs while running sqlite3_backup_step(B,N), 6612 ** then an [error code] is returned. ^As well as [SQLITE_OK] and 6613 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 6614 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 6615 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 6616 ** 6617 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 6618 ** <ol> 6619 ** <li> the destination database was opened read-only, or 6620 ** <li> the destination database is using write-ahead-log journaling 6621 ** and the destination and source page sizes differ, or 6622 ** <li> the destination database is an in-memory database and the 6623 ** destination and source page sizes differ. 6624 ** </ol>)^ 6625 ** 6626 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 6627 ** the [sqlite3_busy_handler | busy-handler function] 6628 ** is invoked (if one is specified). ^If the 6629 ** busy-handler returns non-zero before the lock is available, then 6630 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 6631 ** sqlite3_backup_step() can be retried later. ^If the source 6632 ** [database connection] 6633 ** is being used to write to the source database when sqlite3_backup_step() 6634 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 6635 ** case the call to sqlite3_backup_step() can be retried later on. ^(If 6636 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 6637 ** [SQLITE_READONLY] is returned, then 6638 ** there is no point in retrying the call to sqlite3_backup_step(). These 6639 ** errors are considered fatal.)^ The application must accept 6640 ** that the backup operation has failed and pass the backup operation handle 6641 ** to the sqlite3_backup_finish() to release associated resources. 6642 ** 6643 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock 6644 ** on the destination file. ^The exclusive lock is not released until either 6645 ** sqlite3_backup_finish() is called or the backup operation is complete 6646 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 6647 ** sqlite3_backup_step() obtains a [shared lock] on the source database that 6648 ** lasts for the duration of the sqlite3_backup_step() call. 6649 ** ^Because the source database is not locked between calls to 6650 ** sqlite3_backup_step(), the source database may be modified mid-way 6651 ** through the backup process. ^If the source database is modified by an 6652 ** external process or via a database connection other than the one being 6653 ** used by the backup operation, then the backup will be automatically 6654 ** restarted by the next call to sqlite3_backup_step(). ^If the source 6655 ** database is modified by the using the same database connection as is used 6656 ** by the backup operation, then the backup database is automatically 6657 ** updated at the same time. 6658 ** 6659 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 6660 ** 6661 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 6662 ** application wishes to abandon the backup operation, the application 6663 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 6664 ** ^The sqlite3_backup_finish() interfaces releases all 6665 ** resources associated with the [sqlite3_backup] object. 6666 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 6667 ** active write-transaction on the destination database is rolled back. 6668 ** The [sqlite3_backup] object is invalid 6669 ** and may not be used following a call to sqlite3_backup_finish(). 6670 ** 6671 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 6672 ** sqlite3_backup_step() errors occurred, regardless or whether or not 6673 ** sqlite3_backup_step() completed. 6674 ** ^If an out-of-memory condition or IO error occurred during any prior 6675 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 6676 ** sqlite3_backup_finish() returns the corresponding [error code]. 6677 ** 6678 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 6679 ** is not a permanent error and does not affect the return value of 6680 ** sqlite3_backup_finish(). 6681 ** 6682 ** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]] 6683 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 6684 ** 6685 ** ^Each call to sqlite3_backup_step() sets two values inside 6686 ** the [sqlite3_backup] object: the number of pages still to be backed 6687 ** up and the total number of pages in the source database file. 6688 ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 6689 ** retrieve these two values, respectively. 6690 ** 6691 ** ^The values returned by these functions are only updated by 6692 ** sqlite3_backup_step(). ^If the source database is modified during a backup 6693 ** operation, then the values are not updated to account for any extra 6694 ** pages that need to be updated or the size of the source database file 6695 ** changing. 6696 ** 6697 ** <b>Concurrent Usage of Database Handles</b> 6698 ** 6699 ** ^The source [database connection] may be used by the application for other 6700 ** purposes while a backup operation is underway or being initialized. 6701 ** ^If SQLite is compiled and configured to support threadsafe database 6702 ** connections, then the source database connection may be used concurrently 6703 ** from within other threads. 6704 ** 6705 ** However, the application must guarantee that the destination 6706 ** [database connection] is not passed to any other API (by any thread) after 6707 ** sqlite3_backup_init() is called and before the corresponding call to 6708 ** sqlite3_backup_finish(). SQLite does not currently check to see 6709 ** if the application incorrectly accesses the destination [database connection] 6710 ** and so no error code is reported, but the operations may malfunction 6711 ** nevertheless. Use of the destination database connection while a 6712 ** backup is in progress might also also cause a mutex deadlock. 6713 ** 6714 ** If running in [shared cache mode], the application must 6715 ** guarantee that the shared cache used by the destination database 6716 ** is not accessed while the backup is running. In practice this means 6717 ** that the application must guarantee that the disk file being 6718 ** backed up to is not accessed by any connection within the process, 6719 ** not just the specific connection that was passed to sqlite3_backup_init(). 6720 ** 6721 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple 6722 ** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 6723 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 6724 ** APIs are not strictly speaking threadsafe. If they are invoked at the 6725 ** same time as another thread is invoking sqlite3_backup_step() it is 6726 ** possible that they return invalid values. 6727 */ 6728 SQLITE_API sqlite3_backup *sqlite3_backup_init( 6729 sqlite3 *pDest, /* Destination database handle */ 6730 const char *zDestName, /* Destination database name */ 6731 sqlite3 *pSource, /* Source database handle */ 6732 const char *zSourceName /* Source database name */ 6733 ); 6734 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage); 6735 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p); 6736 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p); 6737 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p); 6738 6739 /* 6740 ** CAPI3REF: Unlock Notification 6741 ** 6742 ** ^When running in shared-cache mode, a database operation may fail with 6743 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 6744 ** individual tables within the shared-cache cannot be obtained. See 6745 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 6746 ** ^This API may be used to register a callback that SQLite will invoke 6747 ** when the connection currently holding the required lock relinquishes it. 6748 ** ^This API is only available if the library was compiled with the 6749 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 6750 ** 6751 ** See Also: [Using the SQLite Unlock Notification Feature]. 6752 ** 6753 ** ^Shared-cache locks are released when a database connection concludes 6754 ** its current transaction, either by committing it or rolling it back. 6755 ** 6756 ** ^When a connection (known as the blocked connection) fails to obtain a 6757 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 6758 ** identity of the database connection (the blocking connection) that 6759 ** has locked the required resource is stored internally. ^After an 6760 ** application receives an SQLITE_LOCKED error, it may call the 6761 ** sqlite3_unlock_notify() method with the blocked connection handle as 6762 ** the first argument to register for a callback that will be invoked 6763 ** when the blocking connections current transaction is concluded. ^The 6764 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 6765 ** call that concludes the blocking connections transaction. 6766 ** 6767 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 6768 ** there is a chance that the blocking connection will have already 6769 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 6770 ** If this happens, then the specified callback is invoked immediately, 6771 ** from within the call to sqlite3_unlock_notify().)^ 6772 ** 6773 ** ^If the blocked connection is attempting to obtain a write-lock on a 6774 ** shared-cache table, and more than one other connection currently holds 6775 ** a read-lock on the same table, then SQLite arbitrarily selects one of 6776 ** the other connections to use as the blocking connection. 6777 ** 6778 ** ^(There may be at most one unlock-notify callback registered by a 6779 ** blocked connection. If sqlite3_unlock_notify() is called when the 6780 ** blocked connection already has a registered unlock-notify callback, 6781 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 6782 ** called with a NULL pointer as its second argument, then any existing 6783 ** unlock-notify callback is canceled. ^The blocked connections 6784 ** unlock-notify callback may also be canceled by closing the blocked 6785 ** connection using [sqlite3_close()]. 6786 ** 6787 ** The unlock-notify callback is not reentrant. If an application invokes 6788 ** any sqlite3_xxx API functions from within an unlock-notify callback, a 6789 ** crash or deadlock may be the result. 6790 ** 6791 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 6792 ** returns SQLITE_OK. 6793 ** 6794 ** <b>Callback Invocation Details</b> 6795 ** 6796 ** When an unlock-notify callback is registered, the application provides a 6797 ** single void* pointer that is passed to the callback when it is invoked. 6798 ** However, the signature of the callback function allows SQLite to pass 6799 ** it an array of void* context pointers. The first argument passed to 6800 ** an unlock-notify callback is a pointer to an array of void* pointers, 6801 ** and the second is the number of entries in the array. 6802 ** 6803 ** When a blocking connections transaction is concluded, there may be 6804 ** more than one blocked connection that has registered for an unlock-notify 6805 ** callback. ^If two or more such blocked connections have specified the 6806 ** same callback function, then instead of invoking the callback function 6807 ** multiple times, it is invoked once with the set of void* context pointers 6808 ** specified by the blocked connections bundled together into an array. 6809 ** This gives the application an opportunity to prioritize any actions 6810 ** related to the set of unblocked database connections. 6811 ** 6812 ** <b>Deadlock Detection</b> 6813 ** 6814 ** Assuming that after registering for an unlock-notify callback a 6815 ** database waits for the callback to be issued before taking any further 6816 ** action (a reasonable assumption), then using this API may cause the 6817 ** application to deadlock. For example, if connection X is waiting for 6818 ** connection Y's transaction to be concluded, and similarly connection 6819 ** Y is waiting on connection X's transaction, then neither connection 6820 ** will proceed and the system may remain deadlocked indefinitely. 6821 ** 6822 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 6823 ** detection. ^If a given call to sqlite3_unlock_notify() would put the 6824 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no 6825 ** unlock-notify callback is registered. The system is said to be in 6826 ** a deadlocked state if connection A has registered for an unlock-notify 6827 ** callback on the conclusion of connection B's transaction, and connection 6828 ** B has itself registered for an unlock-notify callback when connection 6829 ** A's transaction is concluded. ^Indirect deadlock is also detected, so 6830 ** the system is also considered to be deadlocked if connection B has 6831 ** registered for an unlock-notify callback on the conclusion of connection 6832 ** C's transaction, where connection C is waiting on connection A. ^Any 6833 ** number of levels of indirection are allowed. 6834 ** 6835 ** <b>The "DROP TABLE" Exception</b> 6836 ** 6837 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 6838 ** always appropriate to call sqlite3_unlock_notify(). There is however, 6839 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 6840 ** SQLite checks if there are any currently executing SELECT statements 6841 ** that belong to the same connection. If there are, SQLITE_LOCKED is 6842 ** returned. In this case there is no "blocking connection", so invoking 6843 ** sqlite3_unlock_notify() results in the unlock-notify callback being 6844 ** invoked immediately. If the application then re-attempts the "DROP TABLE" 6845 ** or "DROP INDEX" query, an infinite loop might be the result. 6846 ** 6847 ** One way around this problem is to check the extended error code returned 6848 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the 6849 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 6850 ** the special "DROP TABLE/INDEX" case, the extended error code is just 6851 ** SQLITE_LOCKED.)^ 6852 */ 6853 SQLITE_API int sqlite3_unlock_notify( 6854 sqlite3 *pBlocked, /* Waiting connection */ 6855 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 6856 void *pNotifyArg /* Argument to pass to xNotify */ 6857 ); 6858 6859 6860 /* 6861 ** CAPI3REF: String Comparison 6862 ** 6863 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 6864 ** and extensions to compare the contents of two buffers containing UTF-8 6865 ** strings in a case-independent fashion, using the same definition of "case 6866 ** independence" that SQLite uses internally when comparing identifiers. 6867 */ 6868 SQLITE_API int sqlite3_stricmp(const char *, const char *); 6869 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int); 6870 6871 /* 6872 ** CAPI3REF: String Globbing 6873 * 6874 ** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches 6875 ** the glob pattern P, and it returns non-zero if string X does not match 6876 ** the glob pattern P. ^The definition of glob pattern matching used in 6877 ** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 6878 ** SQL dialect used by SQLite. ^The sqlite3_strglob(P,X) function is case 6879 ** sensitive. 6880 ** 6881 ** Note that this routine returns zero on a match and non-zero if the strings 6882 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 6883 */ 6884 SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr); 6885 6886 /* 6887 ** CAPI3REF: Error Logging Interface 6888 ** 6889 ** ^The [sqlite3_log()] interface writes a message into the [error log] 6890 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 6891 ** ^If logging is enabled, the zFormat string and subsequent arguments are 6892 ** used with [sqlite3_snprintf()] to generate the final output string. 6893 ** 6894 ** The sqlite3_log() interface is intended for use by extensions such as 6895 ** virtual tables, collating functions, and SQL functions. While there is 6896 ** nothing to prevent an application from calling sqlite3_log(), doing so 6897 ** is considered bad form. 6898 ** 6899 ** The zFormat string must not be NULL. 6900 ** 6901 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine 6902 ** will not use dynamically allocated memory. The log message is stored in 6903 ** a fixed-length buffer on the stack. If the log message is longer than 6904 ** a few hundred characters, it will be truncated to the length of the 6905 ** buffer. 6906 */ 6907 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...); 6908 6909 /* 6910 ** CAPI3REF: Write-Ahead Log Commit Hook 6911 ** 6912 ** ^The [sqlite3_wal_hook()] function is used to register a callback that 6913 ** will be invoked each time a database connection commits data to a 6914 ** [write-ahead log] (i.e. whenever a transaction is committed in 6915 ** [journal_mode | journal_mode=WAL mode]). 6916 ** 6917 ** ^The callback is invoked by SQLite after the commit has taken place and 6918 ** the associated write-lock on the database released, so the implementation 6919 ** may read, write or [checkpoint] the database as required. 6920 ** 6921 ** ^The first parameter passed to the callback function when it is invoked 6922 ** is a copy of the third parameter passed to sqlite3_wal_hook() when 6923 ** registering the callback. ^The second is a copy of the database handle. 6924 ** ^The third parameter is the name of the database that was written to - 6925 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 6926 ** is the number of pages currently in the write-ahead log file, 6927 ** including those that were just committed. 6928 ** 6929 ** The callback function should normally return [SQLITE_OK]. ^If an error 6930 ** code is returned, that error will propagate back up through the 6931 ** SQLite code base to cause the statement that provoked the callback 6932 ** to report an error, though the commit will have still occurred. If the 6933 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 6934 ** that does not correspond to any valid SQLite error code, the results 6935 ** are undefined. 6936 ** 6937 ** A single database handle may have at most a single write-ahead log callback 6938 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 6939 ** previously registered write-ahead log callback. ^Note that the 6940 ** [sqlite3_wal_autocheckpoint()] interface and the 6941 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 6942 ** those overwrite any prior [sqlite3_wal_hook()] settings. 6943 */ 6944 SQLITE_API void *sqlite3_wal_hook( 6945 sqlite3*, 6946 int(*)(void *,sqlite3*,const char*,int), 6947 void* 6948 ); 6949 6950 /* 6951 ** CAPI3REF: Configure an auto-checkpoint 6952 ** 6953 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 6954 ** [sqlite3_wal_hook()] that causes any database on [database connection] D 6955 ** to automatically [checkpoint] 6956 ** after committing a transaction if there are N or 6957 ** more frames in the [write-ahead log] file. ^Passing zero or 6958 ** a negative value as the nFrame parameter disables automatic 6959 ** checkpoints entirely. 6960 ** 6961 ** ^The callback registered by this function replaces any existing callback 6962 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 6963 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 6964 ** configured by this function. 6965 ** 6966 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 6967 ** from SQL. 6968 ** 6969 ** ^Every new [database connection] defaults to having the auto-checkpoint 6970 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 6971 ** pages. The use of this interface 6972 ** is only necessary if the default setting is found to be suboptimal 6973 ** for a particular application. 6974 */ 6975 SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 6976 6977 /* 6978 ** CAPI3REF: Checkpoint a database 6979 ** 6980 ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 6981 ** on [database connection] D to be [checkpointed]. ^If X is NULL or an 6982 ** empty string, then a checkpoint is run on all databases of 6983 ** connection D. ^If the database connection D is not in 6984 ** [WAL | write-ahead log mode] then this interface is a harmless no-op. 6985 ** 6986 ** ^The [wal_checkpoint pragma] can be used to invoke this interface 6987 ** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 6988 ** [wal_autocheckpoint pragma] can be used to cause this interface to be 6989 ** run whenever the WAL reaches a certain size threshold. 6990 ** 6991 ** See also: [sqlite3_wal_checkpoint_v2()] 6992 */ 6993 SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 6994 6995 /* 6996 ** CAPI3REF: Checkpoint a database 6997 ** 6998 ** Run a checkpoint operation on WAL database zDb attached to database 6999 ** handle db. The specific operation is determined by the value of the 7000 ** eMode parameter: 7001 ** 7002 ** <dl> 7003 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 7004 ** Checkpoint as many frames as possible without waiting for any database 7005 ** readers or writers to finish. Sync the db file if all frames in the log 7006 ** are checkpointed. This mode is the same as calling 7007 ** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked. 7008 ** 7009 ** <dt>SQLITE_CHECKPOINT_FULL<dd> 7010 ** This mode blocks (calls the busy-handler callback) until there is no 7011 ** database writer and all readers are reading from the most recent database 7012 ** snapshot. It then checkpoints all frames in the log file and syncs the 7013 ** database file. This call blocks database writers while it is running, 7014 ** but not database readers. 7015 ** 7016 ** <dt>SQLITE_CHECKPOINT_RESTART<dd> 7017 ** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after 7018 ** checkpointing the log file it blocks (calls the busy-handler callback) 7019 ** until all readers are reading from the database file only. This ensures 7020 ** that the next client to write to the database file restarts the log file 7021 ** from the beginning. This call blocks database writers while it is running, 7022 ** but not database readers. 7023 ** </dl> 7024 ** 7025 ** If pnLog is not NULL, then *pnLog is set to the total number of frames in 7026 ** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to 7027 ** the total number of checkpointed frames (including any that were already 7028 ** checkpointed when this function is called). *pnLog and *pnCkpt may be 7029 ** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK. 7030 ** If no values are available because of an error, they are both set to -1 7031 ** before returning to communicate this to the caller. 7032 ** 7033 ** All calls obtain an exclusive "checkpoint" lock on the database file. If 7034 ** any other process is running a checkpoint operation at the same time, the 7035 ** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a 7036 ** busy-handler configured, it will not be invoked in this case. 7037 ** 7038 ** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive 7039 ** "writer" lock on the database file. If the writer lock cannot be obtained 7040 ** immediately, and a busy-handler is configured, it is invoked and the writer 7041 ** lock retried until either the busy-handler returns 0 or the lock is 7042 ** successfully obtained. The busy-handler is also invoked while waiting for 7043 ** database readers as described above. If the busy-handler returns 0 before 7044 ** the writer lock is obtained or while waiting for database readers, the 7045 ** checkpoint operation proceeds from that point in the same way as 7046 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 7047 ** without blocking any further. SQLITE_BUSY is returned in this case. 7048 ** 7049 ** If parameter zDb is NULL or points to a zero length string, then the 7050 ** specified operation is attempted on all WAL databases. In this case the 7051 ** values written to output parameters *pnLog and *pnCkpt are undefined. If 7052 ** an SQLITE_BUSY error is encountered when processing one or more of the 7053 ** attached WAL databases, the operation is still attempted on any remaining 7054 ** attached databases and SQLITE_BUSY is returned to the caller. If any other 7055 ** error occurs while processing an attached database, processing is abandoned 7056 ** and the error code returned to the caller immediately. If no error 7057 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached 7058 ** databases, SQLITE_OK is returned. 7059 ** 7060 ** If database zDb is the name of an attached database that is not in WAL 7061 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If 7062 ** zDb is not NULL (or a zero length string) and is not the name of any 7063 ** attached database, SQLITE_ERROR is returned to the caller. 7064 */ 7065 SQLITE_API int sqlite3_wal_checkpoint_v2( 7066 sqlite3 *db, /* Database handle */ 7067 const char *zDb, /* Name of attached database (or NULL) */ 7068 int eMode, /* SQLITE_CHECKPOINT_* value */ 7069 int *pnLog, /* OUT: Size of WAL log in frames */ 7070 int *pnCkpt /* OUT: Total number of frames checkpointed */ 7071 ); 7072 7073 /* 7074 ** CAPI3REF: Checkpoint operation parameters 7075 ** 7076 ** These constants can be used as the 3rd parameter to 7077 ** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()] 7078 ** documentation for additional information about the meaning and use of 7079 ** each of these values. 7080 */ 7081 #define SQLITE_CHECKPOINT_PASSIVE 0 7082 #define SQLITE_CHECKPOINT_FULL 1 7083 #define SQLITE_CHECKPOINT_RESTART 2 7084 7085 /* 7086 ** CAPI3REF: Virtual Table Interface Configuration 7087 ** 7088 ** This function may be called by either the [xConnect] or [xCreate] method 7089 ** of a [virtual table] implementation to configure 7090 ** various facets of the virtual table interface. 7091 ** 7092 ** If this interface is invoked outside the context of an xConnect or 7093 ** xCreate virtual table method then the behavior is undefined. 7094 ** 7095 ** At present, there is only one option that may be configured using 7096 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 7097 ** may be added in the future. 7098 */ 7099 SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...); 7100 7101 /* 7102 ** CAPI3REF: Virtual Table Configuration Options 7103 ** 7104 ** These macros define the various options to the 7105 ** [sqlite3_vtab_config()] interface that [virtual table] implementations 7106 ** can use to customize and optimize their behavior. 7107 ** 7108 ** <dl> 7109 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 7110 ** <dd>Calls of the form 7111 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 7112 ** where X is an integer. If X is zero, then the [virtual table] whose 7113 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 7114 ** support constraints. In this configuration (which is the default) if 7115 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 7116 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 7117 ** specified as part of the users SQL statement, regardless of the actual 7118 ** ON CONFLICT mode specified. 7119 ** 7120 ** If X is non-zero, then the virtual table implementation guarantees 7121 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 7122 ** any modifications to internal or persistent data structures have been made. 7123 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 7124 ** is able to roll back a statement or database transaction, and abandon 7125 ** or continue processing the current SQL statement as appropriate. 7126 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 7127 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 7128 ** had been ABORT. 7129 ** 7130 ** Virtual table implementations that are required to handle OR REPLACE 7131 ** must do so within the [xUpdate] method. If a call to the 7132 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON 7133 ** CONFLICT policy is REPLACE, the virtual table implementation should 7134 ** silently replace the appropriate rows within the xUpdate callback and 7135 ** return SQLITE_OK. Or, if this is not possible, it may return 7136 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 7137 ** constraint handling. 7138 ** </dl> 7139 */ 7140 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 7141 7142 /* 7143 ** CAPI3REF: Determine The Virtual Table Conflict Policy 7144 ** 7145 ** This function may only be called from within a call to the [xUpdate] method 7146 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 7147 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 7148 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 7149 ** of the SQL statement that triggered the call to the [xUpdate] method of the 7150 ** [virtual table]. 7151 */ 7152 SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *); 7153 7154 /* 7155 ** CAPI3REF: Conflict resolution modes 7156 ** 7157 ** These constants are returned by [sqlite3_vtab_on_conflict()] to 7158 ** inform a [virtual table] implementation what the [ON CONFLICT] mode 7159 ** is for the SQL statement being evaluated. 7160 ** 7161 ** Note that the [SQLITE_IGNORE] constant is also used as a potential 7162 ** return value from the [sqlite3_set_authorizer()] callback and that 7163 ** [SQLITE_ABORT] is also a [result code]. 7164 */ 7165 #define SQLITE_ROLLBACK 1 7166 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 7167 #define SQLITE_FAIL 3 7168 /* #define SQLITE_ABORT 4 // Also an error code */ 7169 #define SQLITE_REPLACE 5 7170 7171 7172 7173 /* 7174 ** Undo the hack that converts floating point types to integer for 7175 ** builds on processors without floating point support. 7176 */ 7177 #ifdef SQLITE_OMIT_FLOATING_POINT 7178 # undef double 7179 #endif 7180 7181 #ifdef __cplusplus 7182 } /* End of the 'extern "C"' block */ 7183 #endif 7184 #endif 7185 7186 /* 7187 ** 2010 August 30 7188 ** 7189 ** The author disclaims copyright to this source code. In place of 7190 ** a legal notice, here is a blessing: 7191 ** 7192 ** May you do good and not evil. 7193 ** May you find forgiveness for yourself and forgive others. 7194 ** May you share freely, never taking more than you give. 7195 ** 7196 ************************************************************************* 7197 */ 7198 7199 #ifndef _SQLITE3RTREE_H_ 7200 #define _SQLITE3RTREE_H_ 7201 7202 7203 #ifdef __cplusplus 7204 extern "C" { 7205 #endif 7206 7207 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry; 7208 7209 /* 7210 ** Register a geometry callback named zGeom that can be used as part of an 7211 ** R-Tree geometry query as follows: 7212 ** 7213 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...) 7214 */ 7215 SQLITE_API int sqlite3_rtree_geometry_callback( 7216 sqlite3 *db, 7217 const char *zGeom, 7218 #ifdef SQLITE_RTREE_INT_ONLY 7219 int (*xGeom)(sqlite3_rtree_geometry*, int n, sqlite3_int64 *a, int *pRes), 7220 #else 7221 int (*xGeom)(sqlite3_rtree_geometry*, int n, double *a, int *pRes), 7222 #endif 7223 void *pContext 7224 ); 7225 7226 7227 /* 7228 ** A pointer to a structure of the following type is passed as the first 7229 ** argument to callbacks registered using rtree_geometry_callback(). 7230 */ 7231 struct sqlite3_rtree_geometry { 7232 void *pContext; /* Copy of pContext passed to s_r_g_c() */ 7233 int nParam; /* Size of array aParam[] */ 7234 double *aParam; /* Parameters passed to SQL geom function */ 7235 void *pUser; /* Callback implementation user data */ 7236 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */ 7237 }; 7238 7239 7240 #ifdef __cplusplus 7241 } /* end of the 'extern "C"' block */ 7242 #endif 7243 7244 #endif /* ifndef _SQLITE3RTREE_H_ */ 7245 7246