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