1 /* 2 ** 2001 September 15 3 ** 4 ** The author disclaims copyright to this source code. In place of 5 ** a legal notice, here is a blessing: 6 ** 7 ** May you do good and not evil. 8 ** May you find forgiveness for yourself and forgive others. 9 ** May you share freely, never taking more than you give. 10 ** 11 ************************************************************************* 12 ** This header file defines the interface that the SQLite library 13 ** presents to client programs. If a C-function, structure, datatype, 14 ** or constant definition does not appear in this file, then it is 15 ** not a published API of SQLite, is subject to change without 16 ** notice, and should not be referenced by programs that use SQLite. 17 ** 18 ** Some of the definitions that are in this file are marked as 19 ** "experimental". Experimental interfaces are normally new 20 ** features recently added to SQLite. We do not anticipate changes 21 ** to experimental interfaces but reserve the right to make minor changes 22 ** if experience from use "in the wild" suggest such changes are prudent. 23 ** 24 ** The official C-language API documentation for SQLite is derived 25 ** from comments in this file. This file is the authoritative source 26 ** on how SQLite interfaces are suppose to operate. 27 ** 28 ** The name of this file under configuration management is "sqlite.h.in". 29 ** The makefile makes some minor changes to this file (such as inserting 30 ** the version number) and changes its name to "sqlite3.h" as 31 ** part of the build process. 32 */ 33 #ifndef _SQLITE3_H_ 34 #define _SQLITE3_H_ 35 #include <stdarg.h> /* Needed for the definition of va_list */ 36 37 /* 38 ** Make sure we can call this stuff from C++. 39 */ 40 #ifdef __cplusplus 41 extern "C" { 42 #endif 43 44 45 /* 46 ** Add the ability to override 'extern' 47 */ 48 #ifndef SQLITE_EXTERN 49 # define SQLITE_EXTERN extern 50 #endif 51 52 #ifndef SQLITE_API 53 # define SQLITE_API 54 #endif 55 56 57 /* 58 ** These no-op macros are used in front of interfaces to mark those 59 ** interfaces as either deprecated or experimental. New applications 60 ** should not use deprecated interfaces - they are support for backwards 61 ** compatibility only. Application writers should be aware that 62 ** experimental interfaces are subject to change in point releases. 63 ** 64 ** These macros used to resolve to various kinds of compiler magic that 65 ** would generate warning messages when they were used. But that 66 ** compiler magic ended up generating such a flurry of bug reports 67 ** that we have taken it all out and gone back to using simple 68 ** noop macros. 69 */ 70 #define SQLITE_DEPRECATED 71 #define SQLITE_EXPERIMENTAL 72 73 /* 74 ** Ensure these symbols were not defined by some previous header file. 75 */ 76 #ifdef SQLITE_VERSION 77 # undef SQLITE_VERSION 78 #endif 79 #ifdef SQLITE_VERSION_NUMBER 80 # undef SQLITE_VERSION_NUMBER 81 #endif 82 83 /* 84 ** CAPI3REF: Compile-Time Library Version Numbers 85 ** 86 ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 87 ** evaluates to a string literal that is the SQLite version in the 88 ** format "X.Y.Z" where X is the major version number (always 3 for 89 ** SQLite3) and Y is the minor version number and Z is the release number.)^ 90 ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 91 ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 92 ** numbers used in [SQLITE_VERSION].)^ 93 ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 94 ** be larger than the release from which it is derived. Either Y will 95 ** be held constant and Z will be incremented or else Y will be incremented 96 ** and Z will be reset to zero. 97 ** 98 ** Since version 3.6.18, SQLite source code has been stored in the 99 ** <a href="http://www.fossil-scm.org/">Fossil configuration management 100 ** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 101 ** a string which identifies a particular check-in of SQLite 102 ** within its configuration management system. ^The SQLITE_SOURCE_ID 103 ** string contains the date and time of the check-in (UTC) and an SHA1 104 ** hash of the entire source tree. 105 ** 106 ** See also: [sqlite3_libversion()], 107 ** [sqlite3_libversion_number()], [sqlite3_sourceid()], 108 ** [sqlite_version()] and [sqlite_source_id()]. 109 */ 110 #define SQLITE_VERSION "3.7.16.2" 111 #define SQLITE_VERSION_NUMBER 3007016 112 #define SQLITE_SOURCE_ID "2013-04-12 11:52:43 cbea02d93865ce0e06789db95fd9168ebac970c7" 113 114 /* 115 ** CAPI3REF: Run-Time Library Version Numbers 116 ** KEYWORDS: sqlite3_version, sqlite3_sourceid 117 ** 118 ** These interfaces provide the same information as the [SQLITE_VERSION], 119 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 120 ** but are associated with the library instead of the header file. ^(Cautious 121 ** programmers might include assert() statements in their application to 122 ** verify that values returned by these interfaces match the macros in 123 ** the header, and thus insure that the application is 124 ** compiled with matching library and header files. 125 ** 126 ** <blockquote><pre> 127 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 128 ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 129 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 130 ** </pre></blockquote>)^ 131 ** 132 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 133 ** macro. ^The sqlite3_libversion() function returns a pointer to the 134 ** to the sqlite3_version[] string constant. The sqlite3_libversion() 135 ** function is provided for use in DLLs since DLL users usually do not have 136 ** direct access to string constants within the DLL. ^The 137 ** sqlite3_libversion_number() function returns an integer equal to 138 ** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 139 ** a pointer to a string constant whose value is the same as the 140 ** [SQLITE_SOURCE_ID] C preprocessor macro. 141 ** 142 ** See also: [sqlite_version()] and [sqlite_source_id()]. 143 */ 144 SQLITE_API SQLITE_EXTERN const char sqlite3_version[]; 145 SQLITE_API const char *sqlite3_libversion(void); 146 SQLITE_API const char *sqlite3_sourceid(void); 147 SQLITE_API int sqlite3_libversion_number(void); 148 149 /* 150 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics 151 ** 152 ** ^The sqlite3_compileoption_used() function returns 0 or 1 153 ** indicating whether the specified option was defined at 154 ** compile time. ^The SQLITE_ prefix may be omitted from the 155 ** option name passed to sqlite3_compileoption_used(). 156 ** 157 ** ^The sqlite3_compileoption_get() function allows iterating 158 ** over the list of options that were defined at compile time by 159 ** returning the N-th compile time option string. ^If N is out of range, 160 ** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 161 ** prefix is omitted from any strings returned by 162 ** sqlite3_compileoption_get(). 163 ** 164 ** ^Support for the diagnostic functions sqlite3_compileoption_used() 165 ** and sqlite3_compileoption_get() may be omitted by specifying the 166 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 167 ** 168 ** See also: SQL functions [sqlite_compileoption_used()] and 169 ** [sqlite_compileoption_get()] and the [compile_options pragma]. 170 */ 171 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 172 SQLITE_API int sqlite3_compileoption_used(const char *zOptName); 173 SQLITE_API const char *sqlite3_compileoption_get(int N); 174 #endif 175 176 /* 177 ** CAPI3REF: Test To See If The Library Is Threadsafe 178 ** 179 ** ^The sqlite3_threadsafe() function returns zero if and only if 180 ** SQLite was compiled with mutexing code omitted due to the 181 ** [SQLITE_THREADSAFE] compile-time option being set to 0. 182 ** 183 ** SQLite can be compiled with or without mutexes. When 184 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 185 ** are enabled and SQLite is threadsafe. When the 186 ** [SQLITE_THREADSAFE] macro is 0, 187 ** the mutexes are omitted. Without the mutexes, it is not safe 188 ** to use SQLite concurrently from more than one thread. 189 ** 190 ** Enabling mutexes incurs a measurable performance penalty. 191 ** So if speed is of utmost importance, it makes sense to disable 192 ** the mutexes. But for maximum safety, mutexes should be enabled. 193 ** ^The default behavior is for mutexes to be enabled. 194 ** 195 ** This interface can be used by an application to make sure that the 196 ** version of SQLite that it is linking against was compiled with 197 ** the desired setting of the [SQLITE_THREADSAFE] macro. 198 ** 199 ** This interface only reports on the compile-time mutex setting 200 ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 201 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 202 ** can be fully or partially disabled using a call to [sqlite3_config()] 203 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 204 ** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the 205 ** sqlite3_threadsafe() function shows only the compile-time setting of 206 ** thread safety, not any run-time changes to that setting made by 207 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 208 ** is unchanged by calls to sqlite3_config().)^ 209 ** 210 ** See the [threading mode] documentation for additional information. 211 */ 212 SQLITE_API int sqlite3_threadsafe(void); 213 214 /* 215 ** CAPI3REF: Database Connection Handle 216 ** KEYWORDS: {database connection} {database connections} 217 ** 218 ** Each open SQLite database is represented by a pointer to an instance of 219 ** the opaque structure named "sqlite3". It is useful to think of an sqlite3 220 ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 221 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 222 ** and [sqlite3_close_v2()] are its destructors. There are many other 223 ** interfaces (such as 224 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 225 ** [sqlite3_busy_timeout()] to name but three) that are methods on an 226 ** sqlite3 object. 227 */ 228 typedef struct sqlite3 sqlite3; 229 230 /* 231 ** CAPI3REF: 64-Bit Integer Types 232 ** KEYWORDS: sqlite_int64 sqlite_uint64 233 ** 234 ** Because there is no cross-platform way to specify 64-bit integer types 235 ** SQLite includes typedefs for 64-bit signed and unsigned integers. 236 ** 237 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 238 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards 239 ** compatibility only. 240 ** 241 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values 242 ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 243 ** sqlite3_uint64 and sqlite_uint64 types can store integer values 244 ** between 0 and +18446744073709551615 inclusive. 245 */ 246 #ifdef SQLITE_INT64_TYPE 247 typedef SQLITE_INT64_TYPE sqlite_int64; 248 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 249 #elif defined(_MSC_VER) || defined(__BORLANDC__) 250 typedef __int64 sqlite_int64; 251 typedef unsigned __int64 sqlite_uint64; 252 #else 253 typedef long long int sqlite_int64; 254 typedef unsigned long long int sqlite_uint64; 255 #endif 256 typedef sqlite_int64 sqlite3_int64; 257 typedef sqlite_uint64 sqlite3_uint64; 258 259 /* 260 ** If compiling for a processor that lacks floating point support, 261 ** substitute integer for floating-point. 262 */ 263 #ifdef SQLITE_OMIT_FLOATING_POINT 264 # define double sqlite3_int64 265 #endif 266 267 /* 268 ** CAPI3REF: Closing A Database Connection 269 ** 270 ** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 271 ** for the [sqlite3] object. 272 ** ^Calls to sqlite3_close() and sqlite3_close_v2() return SQLITE_OK if 273 ** the [sqlite3] object is successfully destroyed and all associated 274 ** resources are deallocated. 275 ** 276 ** ^If the database connection is associated with unfinalized prepared 277 ** statements or unfinished sqlite3_backup objects then sqlite3_close() 278 ** will leave the database connection open and return [SQLITE_BUSY]. 279 ** ^If sqlite3_close_v2() is called with unfinalized prepared statements 280 ** and unfinished sqlite3_backups, then the database connection becomes 281 ** an unusable "zombie" which will automatically be deallocated when the 282 ** last prepared statement is finalized or the last sqlite3_backup is 283 ** finished. The sqlite3_close_v2() interface is intended for use with 284 ** host languages that are garbage collected, and where the order in which 285 ** destructors are called is arbitrary. 286 ** 287 ** Applications should [sqlite3_finalize | finalize] all [prepared statements], 288 ** [sqlite3_blob_close | close] all [BLOB handles], and 289 ** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 290 ** with the [sqlite3] object prior to attempting to close the object. ^If 291 ** sqlite3_close_v2() is called on a [database connection] that still has 292 ** outstanding [prepared statements], [BLOB handles], and/or 293 ** [sqlite3_backup] objects then it returns SQLITE_OK but the deallocation 294 ** of resources is deferred until all [prepared statements], [BLOB handles], 295 ** and [sqlite3_backup] objects are also destroyed. 296 ** 297 ** ^If an [sqlite3] object is destroyed while a transaction is open, 298 ** the transaction is automatically rolled back. 299 ** 300 ** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 301 ** must be either a NULL 302 ** pointer or an [sqlite3] object pointer obtained 303 ** from [sqlite3_open()], [sqlite3_open16()], or 304 ** [sqlite3_open_v2()], and not previously closed. 305 ** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 306 ** argument is a harmless no-op. 307 */ 308 SQLITE_API int sqlite3_close(sqlite3*); 309 SQLITE_API int sqlite3_close_v2(sqlite3*); 310 311 /* 312 ** The type for a callback function. 313 ** This is legacy and deprecated. It is included for historical 314 ** compatibility and is not documented. 315 */ 316 typedef int (*sqlite3_callback)(void*,int,char**, char**); 317 318 /* 319 ** CAPI3REF: One-Step Query Execution Interface 320 ** 321 ** The sqlite3_exec() interface is a convenience wrapper around 322 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 323 ** that allows an application to run multiple statements of SQL 324 ** without having to use a lot of C code. 325 ** 326 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 327 ** semicolon-separate SQL statements passed into its 2nd argument, 328 ** in the context of the [database connection] passed in as its 1st 329 ** argument. ^If the callback function of the 3rd argument to 330 ** sqlite3_exec() is not NULL, then it is invoked for each result row 331 ** coming out of the evaluated SQL statements. ^The 4th argument to 332 ** sqlite3_exec() is relayed through to the 1st argument of each 333 ** callback invocation. ^If the callback pointer to sqlite3_exec() 334 ** is NULL, then no callback is ever invoked and result rows are 335 ** ignored. 336 ** 337 ** ^If an error occurs while evaluating the SQL statements passed into 338 ** sqlite3_exec(), then execution of the current statement stops and 339 ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 340 ** is not NULL then any error message is written into memory obtained 341 ** from [sqlite3_malloc()] and passed back through the 5th parameter. 342 ** To avoid memory leaks, the application should invoke [sqlite3_free()] 343 ** on error message strings returned through the 5th parameter of 344 ** of sqlite3_exec() after the error message string is no longer needed. 345 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 346 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 347 ** NULL before returning. 348 ** 349 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 350 ** routine returns SQLITE_ABORT without invoking the callback again and 351 ** without running any subsequent SQL statements. 352 ** 353 ** ^The 2nd argument to the sqlite3_exec() callback function is the 354 ** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 355 ** callback is an array of pointers to strings obtained as if from 356 ** [sqlite3_column_text()], one for each column. ^If an element of a 357 ** result row is NULL then the corresponding string pointer for the 358 ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 359 ** sqlite3_exec() callback is an array of pointers to strings where each 360 ** entry represents the name of corresponding result column as obtained 361 ** from [sqlite3_column_name()]. 362 ** 363 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 364 ** to an empty string, or a pointer that contains only whitespace and/or 365 ** SQL comments, then no SQL statements are evaluated and the database 366 ** is not changed. 367 ** 368 ** Restrictions: 369 ** 370 ** <ul> 371 ** <li> The application must insure that the 1st parameter to sqlite3_exec() 372 ** is a valid and open [database connection]. 373 ** <li> The application must not close [database connection] specified by 374 ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 375 ** <li> The application must not modify the SQL statement text passed into 376 ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 377 ** </ul> 378 */ 379 SQLITE_API int sqlite3_exec( 380 sqlite3*, /* An open database */ 381 const char *sql, /* SQL to be evaluated */ 382 int (*callback)(void*,int,char**,char**), /* Callback function */ 383 void *, /* 1st argument to callback */ 384 char **errmsg /* Error msg written here */ 385 ); 386 387 /* 388 ** CAPI3REF: Result Codes 389 ** KEYWORDS: SQLITE_OK {error code} {error codes} 390 ** KEYWORDS: {result code} {result codes} 391 ** 392 ** Many SQLite functions return an integer result code from the set shown 393 ** here in order to indicate success or failure. 394 ** 395 ** New error codes may be added in future versions of SQLite. 396 ** 397 ** See also: [SQLITE_IOERR_READ | extended result codes], 398 ** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes]. 399 */ 400 #define SQLITE_OK 0 /* Successful result */ 401 /* beginning-of-error-codes */ 402 #define SQLITE_ERROR 1 /* SQL error or missing database */ 403 #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 404 #define SQLITE_PERM 3 /* Access permission denied */ 405 #define SQLITE_ABORT 4 /* Callback routine requested an abort */ 406 #define SQLITE_BUSY 5 /* The database file is locked */ 407 #define SQLITE_LOCKED 6 /* A table in the database is locked */ 408 #define SQLITE_NOMEM 7 /* A malloc() failed */ 409 #define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 410 #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 411 #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 412 #define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 413 #define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 414 #define SQLITE_FULL 13 /* Insertion failed because database is full */ 415 #define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 416 #define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 417 #define SQLITE_EMPTY 16 /* Database is empty */ 418 #define SQLITE_SCHEMA 17 /* The database schema changed */ 419 #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 420 #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 421 #define SQLITE_MISMATCH 20 /* Data type mismatch */ 422 #define SQLITE_MISUSE 21 /* Library used incorrectly */ 423 #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 424 #define SQLITE_AUTH 23 /* Authorization denied */ 425 #define SQLITE_FORMAT 24 /* Auxiliary database format error */ 426 #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 427 #define SQLITE_NOTADB 26 /* File opened that is not a database file */ 428 #define SQLITE_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 error code} {extended error codes} 435 ** KEYWORDS: {extended result code} {extended result codes} 436 ** 437 ** In its default configuration, SQLite API routines return one of 26 integer 438 ** [SQLITE_OK | result codes]. However, experience has shown that many of 439 ** these result codes are too coarse-grained. They do not provide as 440 ** much information about problems as programmers might like. In an effort to 441 ** address this, newer versions of SQLite (version 3.3.8 and later) include 442 ** support for additional result codes that provide more detailed information 443 ** about errors. The extended result codes are enabled or disabled 444 ** on a per database connection basis using the 445 ** [sqlite3_extended_result_codes()] API. 446 ** 447 ** Some of the available extended result codes are listed here. 448 ** One may expect the number of extended result codes will be expand 449 ** over time. Software that uses extended result codes should expect 450 ** to see new result codes in future releases of SQLite. 451 ** 452 ** The SQLITE_OK result code will never be extended. It will always 453 ** be exactly zero. 454 */ 455 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 456 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 457 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 458 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 459 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 460 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 461 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 462 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 463 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 464 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 465 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 466 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 467 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 468 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 469 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 470 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 471 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 472 #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 473 #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 474 #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 475 #define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 476 #define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 477 #define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 478 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 479 #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 480 #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 481 #define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 482 #define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 483 #define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 484 #define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 485 #define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 486 #define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 487 #define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 488 #define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 489 #define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 490 #define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 491 #define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 492 #define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 493 #define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 494 #define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 495 #define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 496 #define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 497 498 /* 499 ** CAPI3REF: Flags For File Open Operations 500 ** 501 ** These bit values are intended for use in the 502 ** 3rd parameter to the [sqlite3_open_v2()] interface and 503 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 504 */ 505 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 506 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 507 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 508 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 509 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 510 #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 511 #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 512 #define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 513 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 514 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 515 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 516 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 517 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 518 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 519 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 520 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 521 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 522 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 523 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 524 #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 525 526 /* Reserved: 0x00F00000 */ 527 528 /* 529 ** CAPI3REF: Device Characteristics 530 ** 531 ** The xDeviceCharacteristics method of the [sqlite3_io_methods] 532 ** object returns an integer which is a vector of these 533 ** bit values expressing I/O characteristics of the mass storage 534 ** device that holds the file that the [sqlite3_io_methods] 535 ** refers to. 536 ** 537 ** The SQLITE_IOCAP_ATOMIC property means that all writes of 538 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 539 ** mean that writes of blocks that are nnn bytes in size and 540 ** are aligned to an address which is an integer multiple of 541 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 542 ** that when data is appended to a file, the data is appended 543 ** first then the size of the file is extended, never the other 544 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 545 ** information is written to disk in the same order as calls 546 ** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 547 ** after reboot following a crash or power loss, the only bytes in a 548 ** file that were written at the application level might have changed 549 ** and that adjacent bytes, even bytes within the same sector are 550 ** guaranteed to be unchanged. 551 */ 552 #define SQLITE_IOCAP_ATOMIC 0x00000001 553 #define SQLITE_IOCAP_ATOMIC512 0x00000002 554 #define SQLITE_IOCAP_ATOMIC1K 0x00000004 555 #define SQLITE_IOCAP_ATOMIC2K 0x00000008 556 #define SQLITE_IOCAP_ATOMIC4K 0x00000010 557 #define SQLITE_IOCAP_ATOMIC8K 0x00000020 558 #define SQLITE_IOCAP_ATOMIC16K 0x00000040 559 #define SQLITE_IOCAP_ATOMIC32K 0x00000080 560 #define SQLITE_IOCAP_ATOMIC64K 0x00000100 561 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200 562 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400 563 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 564 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 565 566 /* 567 ** CAPI3REF: File Locking Levels 568 ** 569 ** SQLite uses one of these integer values as the second 570 ** argument to calls it makes to the xLock() and xUnlock() methods 571 ** of an [sqlite3_io_methods] object. 572 */ 573 #define SQLITE_LOCK_NONE 0 574 #define SQLITE_LOCK_SHARED 1 575 #define SQLITE_LOCK_RESERVED 2 576 #define SQLITE_LOCK_PENDING 3 577 #define SQLITE_LOCK_EXCLUSIVE 4 578 579 /* 580 ** CAPI3REF: Synchronization Type Flags 581 ** 582 ** When SQLite invokes the xSync() method of an 583 ** [sqlite3_io_methods] object it uses a combination of 584 ** these integer values as the second argument. 585 ** 586 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 587 ** sync operation only needs to flush data to mass storage. Inode 588 ** information need not be flushed. If the lower four bits of the flag 589 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 590 ** If the lower four bits equal SQLITE_SYNC_FULL, that means 591 ** to use Mac OS X style fullsync instead of fsync(). 592 ** 593 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 594 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 595 ** settings. The [synchronous pragma] determines when calls to the 596 ** xSync VFS method occur and applies uniformly across all platforms. 597 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 598 ** energetic or rigorous or forceful the sync operations are and 599 ** only make a difference on Mac OSX for the default SQLite code. 600 ** (Third-party VFS implementations might also make the distinction 601 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 602 ** operating systems natively supported by SQLite, only Mac OSX 603 ** cares about the difference.) 604 */ 605 #define SQLITE_SYNC_NORMAL 0x00002 606 #define SQLITE_SYNC_FULL 0x00003 607 #define SQLITE_SYNC_DATAONLY 0x00010 608 609 /* 610 ** CAPI3REF: OS Interface Open File Handle 611 ** 612 ** An [sqlite3_file] object represents an open file in the 613 ** [sqlite3_vfs | OS interface layer]. Individual OS interface 614 ** implementations will 615 ** want to subclass this object by appending additional fields 616 ** for their own use. The pMethods entry is a pointer to an 617 ** [sqlite3_io_methods] object that defines methods for performing 618 ** I/O operations on the open file. 619 */ 620 typedef struct sqlite3_file sqlite3_file; 621 struct sqlite3_file { 622 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 623 }; 624 625 /* 626 ** CAPI3REF: OS Interface File Virtual Methods Object 627 ** 628 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an 629 ** [sqlite3_file] object (or, more commonly, a subclass of the 630 ** [sqlite3_file] object) with a pointer to an instance of this object. 631 ** This object defines the methods used to perform various operations 632 ** against the open file represented by the [sqlite3_file] object. 633 ** 634 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 635 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 636 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 637 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 638 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 639 ** to NULL. 640 ** 641 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 642 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 643 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 644 ** flag may be ORed in to indicate that only the data of the file 645 ** and not its inode needs to be synced. 646 ** 647 ** The integer values to xLock() and xUnlock() are one of 648 ** <ul> 649 ** <li> [SQLITE_LOCK_NONE], 650 ** <li> [SQLITE_LOCK_SHARED], 651 ** <li> [SQLITE_LOCK_RESERVED], 652 ** <li> [SQLITE_LOCK_PENDING], or 653 ** <li> [SQLITE_LOCK_EXCLUSIVE]. 654 ** </ul> 655 ** xLock() increases the lock. xUnlock() decreases the lock. 656 ** The xCheckReservedLock() method checks whether any database connection, 657 ** either in this process or in some other process, is holding a RESERVED, 658 ** PENDING, or EXCLUSIVE lock on the file. It returns true 659 ** if such a lock exists and false otherwise. 660 ** 661 ** The xFileControl() method is a generic interface that allows custom 662 ** VFS implementations to directly control an open file using the 663 ** [sqlite3_file_control()] interface. The second "op" argument is an 664 ** integer opcode. The third argument is a generic pointer intended to 665 ** point to a structure that may contain arguments or space in which to 666 ** write return values. Potential uses for xFileControl() might be 667 ** functions to enable blocking locks with timeouts, to change the 668 ** locking strategy (for example to use dot-file locks), to inquire 669 ** about the status of a lock, or to break stale locks. The SQLite 670 ** core reserves all opcodes less than 100 for its own use. 671 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 672 ** Applications that define a custom xFileControl method should use opcodes 673 ** greater than 100 to avoid conflicts. VFS implementations should 674 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not 675 ** recognize. 676 ** 677 ** The xSectorSize() method returns the sector size of the 678 ** device that underlies the file. The sector size is the 679 ** minimum write that can be performed without disturbing 680 ** other bytes in the file. The xDeviceCharacteristics() 681 ** method returns a bit vector describing behaviors of the 682 ** underlying device: 683 ** 684 ** <ul> 685 ** <li> [SQLITE_IOCAP_ATOMIC] 686 ** <li> [SQLITE_IOCAP_ATOMIC512] 687 ** <li> [SQLITE_IOCAP_ATOMIC1K] 688 ** <li> [SQLITE_IOCAP_ATOMIC2K] 689 ** <li> [SQLITE_IOCAP_ATOMIC4K] 690 ** <li> [SQLITE_IOCAP_ATOMIC8K] 691 ** <li> [SQLITE_IOCAP_ATOMIC16K] 692 ** <li> [SQLITE_IOCAP_ATOMIC32K] 693 ** <li> [SQLITE_IOCAP_ATOMIC64K] 694 ** <li> [SQLITE_IOCAP_SAFE_APPEND] 695 ** <li> [SQLITE_IOCAP_SEQUENTIAL] 696 ** </ul> 697 ** 698 ** The SQLITE_IOCAP_ATOMIC property means that all writes of 699 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 700 ** mean that writes of blocks that are nnn bytes in size and 701 ** are aligned to an address which is an integer multiple of 702 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 703 ** that when data is appended to a file, the data is appended 704 ** first then the size of the file is extended, never the other 705 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 706 ** information is written to disk in the same order as calls 707 ** to xWrite(). 708 ** 709 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 710 ** in the unread portions of the buffer with zeros. A VFS that 711 ** fails to zero-fill short reads might seem to work. However, 712 ** failure to zero-fill short reads will eventually lead to 713 ** database corruption. 714 */ 715 typedef struct sqlite3_io_methods sqlite3_io_methods; 716 struct sqlite3_io_methods { 717 int iVersion; 718 int (*xClose)(sqlite3_file*); 719 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 720 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 721 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 722 int (*xSync)(sqlite3_file*, int flags); 723 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 724 int (*xLock)(sqlite3_file*, int); 725 int (*xUnlock)(sqlite3_file*, int); 726 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 727 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 728 int (*xSectorSize)(sqlite3_file*); 729 int (*xDeviceCharacteristics)(sqlite3_file*); 730 /* Methods above are valid for version 1 */ 731 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 732 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 733 void (*xShmBarrier)(sqlite3_file*); 734 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 735 /* Methods above are valid for version 2 */ 736 /* Additional methods may be added in future releases */ 737 }; 738 739 /* 740 ** CAPI3REF: Standard File Control Opcodes 741 ** 742 ** These integer constants are opcodes for the xFileControl method 743 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 744 ** interface. 745 ** 746 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 747 ** opcode causes the xFileControl method to write the current state of 748 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 749 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 750 ** into an integer that the pArg argument points to. This capability 751 ** is used during testing and only needs to be supported when SQLITE_TEST 752 ** is defined. 753 ** <ul> 754 ** <li>[[SQLITE_FCNTL_SIZE_HINT]] 755 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 756 ** layer a hint of how large the database file will grow to be during the 757 ** current transaction. This hint is not guaranteed to be accurate but it 758 ** is often close. The underlying VFS might choose to preallocate database 759 ** file space based on this hint in order to help writes to the database 760 ** file run faster. 761 ** 762 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 763 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 764 ** extends and truncates the database file in chunks of a size specified 765 ** by the user. The fourth argument to [sqlite3_file_control()] should 766 ** point to an integer (type int) containing the new chunk-size to use 767 ** for the nominated database. Allocating database file space in large 768 ** chunks (say 1MB at a time), may reduce file-system fragmentation and 769 ** improve performance on some systems. 770 ** 771 ** <li>[[SQLITE_FCNTL_FILE_POINTER]] 772 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 773 ** to the [sqlite3_file] object associated with a particular database 774 ** connection. See the [sqlite3_file_control()] documentation for 775 ** additional information. 776 ** 777 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 778 ** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by 779 ** SQLite and sent to all VFSes in place of a call to the xSync method 780 ** when the database connection has [PRAGMA synchronous] set to OFF.)^ 781 ** Some specialized VFSes need this signal in order to operate correctly 782 ** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most 783 ** VFSes do not need this signal and should silently ignore this opcode. 784 ** Applications should not call [sqlite3_file_control()] with this 785 ** opcode as doing so may disrupt the operation of the specialized VFSes 786 ** that do require it. 787 ** 788 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 789 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 790 ** retry counts and intervals for certain disk I/O operations for the 791 ** windows [VFS] in order to provide robustness in the presence of 792 ** anti-virus programs. By default, the windows VFS will retry file read, 793 ** file write, and file delete operations up to 10 times, with a delay 794 ** of 25 milliseconds before the first retry and with the delay increasing 795 ** by an additional 25 milliseconds with each subsequent retry. This 796 ** opcode allows these two values (10 retries and 25 milliseconds of delay) 797 ** to be adjusted. The values are changed for all database connections 798 ** within the same process. The argument is a pointer to an array of two 799 ** integers where the first integer i the new retry count and the second 800 ** integer is the delay. If either integer is negative, then the setting 801 ** is not changed but instead the prior value of that setting is written 802 ** into the array entry, allowing the current retry settings to be 803 ** interrogated. The zDbName parameter is ignored. 804 ** 805 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 806 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 807 ** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 808 ** write ahead log and shared memory files used for transaction control 809 ** are automatically deleted when the latest connection to the database 810 ** closes. Setting persistent WAL mode causes those files to persist after 811 ** close. Persisting the files is useful when other processes that do not 812 ** have write permission on the directory containing the database file want 813 ** to read the database file, as the WAL and shared memory files must exist 814 ** in order for the database to be readable. The fourth parameter to 815 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 816 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 817 ** WAL mode. If the integer is -1, then it is overwritten with the current 818 ** WAL persistence setting. 819 ** 820 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 821 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 822 ** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 823 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 824 ** xDeviceCharacteristics methods. The fourth parameter to 825 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 826 ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 827 ** mode. If the integer is -1, then it is overwritten with the current 828 ** zero-damage mode setting. 829 ** 830 ** <li>[[SQLITE_FCNTL_OVERWRITE]] 831 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 832 ** a write transaction to indicate that, unless it is rolled back for some 833 ** reason, the entire database file will be overwritten by the current 834 ** transaction. This is used by VACUUM operations. 835 ** 836 ** <li>[[SQLITE_FCNTL_VFSNAME]] 837 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 838 ** all [VFSes] in the VFS stack. The names are of all VFS shims and the 839 ** final bottom-level VFS are written into memory obtained from 840 ** [sqlite3_malloc()] and the result is stored in the char* variable 841 ** that the fourth parameter of [sqlite3_file_control()] points to. 842 ** The caller is responsible for freeing the memory when done. As with 843 ** all file-control actions, there is no guarantee that this will actually 844 ** do anything. Callers should initialize the char* variable to a NULL 845 ** pointer in case this file-control is not implemented. This file-control 846 ** is intended for diagnostic use only. 847 ** 848 ** <li>[[SQLITE_FCNTL_PRAGMA]] 849 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 850 ** file control is sent to the open [sqlite3_file] object corresponding 851 ** to the database file to which the pragma statement refers. ^The argument 852 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 853 ** pointers to strings (char**) in which the second element of the array 854 ** is the name of the pragma and the third element is the argument to the 855 ** pragma or NULL if the pragma has no argument. ^The handler for an 856 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 857 ** of the char** argument point to a string obtained from [sqlite3_mprintf()] 858 ** or the equivalent and that string will become the result of the pragma or 859 ** the error message if the pragma fails. ^If the 860 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 861 ** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 862 ** file control returns [SQLITE_OK], then the parser assumes that the 863 ** VFS has handled the PRAGMA itself and the parser generates a no-op 864 ** prepared statement. ^If the [SQLITE_FCNTL_PRAGMA] file control returns 865 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 866 ** that the VFS encountered an error while handling the [PRAGMA] and the 867 ** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 868 ** file control occurs at the beginning of pragma statement analysis and so 869 ** it is able to override built-in [PRAGMA] statements. 870 ** 871 ** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 872 ** ^This file-control may be invoked by SQLite on the database file handle 873 ** shortly after it is opened in order to provide a custom VFS with access 874 ** to the connections busy-handler callback. The argument is of type (void **) 875 ** - an array of two (void *) values. The first (void *) actually points 876 ** to a function of type (int (*)(void *)). In order to invoke the connections 877 ** busy-handler, this function should be invoked with the second (void *) in 878 ** the array as the only argument. If it returns non-zero, then the operation 879 ** should be retried. If it returns zero, the custom VFS should abandon the 880 ** current operation. 881 ** 882 ** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 883 ** ^Application can invoke this file-control to have SQLite generate a 884 ** temporary filename using the same algorithm that is followed to generate 885 ** temporary filenames for TEMP tables and other internal uses. The 886 ** argument should be a char** which will be filled with the filename 887 ** written into memory obtained from [sqlite3_malloc()]. The caller should 888 ** invoke [sqlite3_free()] on the result to avoid a memory leak. 889 ** 890 ** </ul> 891 */ 892 #define SQLITE_FCNTL_LOCKSTATE 1 893 #define SQLITE_GET_LOCKPROXYFILE 2 894 #define SQLITE_SET_LOCKPROXYFILE 3 895 #define SQLITE_LAST_ERRNO 4 896 #define SQLITE_FCNTL_SIZE_HINT 5 897 #define SQLITE_FCNTL_CHUNK_SIZE 6 898 #define SQLITE_FCNTL_FILE_POINTER 7 899 #define SQLITE_FCNTL_SYNC_OMITTED 8 900 #define SQLITE_FCNTL_WIN32_AV_RETRY 9 901 #define SQLITE_FCNTL_PERSIST_WAL 10 902 #define SQLITE_FCNTL_OVERWRITE 11 903 #define SQLITE_FCNTL_VFSNAME 12 904 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 905 #define SQLITE_FCNTL_PRAGMA 14 906 #define SQLITE_FCNTL_BUSYHANDLER 15 907 #define SQLITE_FCNTL_TEMPFILENAME 16 908 909 /* 910 ** CAPI3REF: Mutex Handle 911 ** 912 ** The mutex module within SQLite defines [sqlite3_mutex] to be an 913 ** abstract type for a mutex object. The SQLite core never looks 914 ** at the internal representation of an [sqlite3_mutex]. It only 915 ** deals with pointers to the [sqlite3_mutex] object. 916 ** 917 ** Mutexes are created using [sqlite3_mutex_alloc()]. 918 */ 919 typedef struct sqlite3_mutex sqlite3_mutex; 920 921 /* 922 ** CAPI3REF: OS Interface Object 923 ** 924 ** An instance of the sqlite3_vfs object defines the interface between 925 ** the SQLite core and the underlying operating system. The "vfs" 926 ** in the name of the object stands for "virtual file system". See 927 ** the [VFS | VFS documentation] for further information. 928 ** 929 ** The value of the iVersion field is initially 1 but may be larger in 930 ** future versions of SQLite. Additional fields may be appended to this 931 ** object when the iVersion value is increased. Note that the structure 932 ** of the sqlite3_vfs object changes in the transaction between 933 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 934 ** modified. 935 ** 936 ** The szOsFile field is the size of the subclassed [sqlite3_file] 937 ** structure used by this VFS. mxPathname is the maximum length of 938 ** a pathname in this VFS. 939 ** 940 ** Registered sqlite3_vfs objects are kept on a linked list formed by 941 ** the pNext pointer. The [sqlite3_vfs_register()] 942 ** and [sqlite3_vfs_unregister()] interfaces manage this list 943 ** in a thread-safe way. The [sqlite3_vfs_find()] interface 944 ** searches the list. Neither the application code nor the VFS 945 ** implementation should use the pNext pointer. 946 ** 947 ** The pNext field is the only field in the sqlite3_vfs 948 ** structure that SQLite will ever modify. SQLite will only access 949 ** or modify this field while holding a particular static mutex. 950 ** The application should never modify anything within the sqlite3_vfs 951 ** object once the object has been registered. 952 ** 953 ** The zName field holds the name of the VFS module. The name must 954 ** be unique across all VFS modules. 955 ** 956 ** [[sqlite3_vfs.xOpen]] 957 ** ^SQLite guarantees that the zFilename parameter to xOpen 958 ** is either a NULL pointer or string obtained 959 ** from xFullPathname() with an optional suffix added. 960 ** ^If a suffix is added to the zFilename parameter, it will 961 ** consist of a single "-" character followed by no more than 962 ** 11 alphanumeric and/or "-" characters. 963 ** ^SQLite further guarantees that 964 ** the string will be valid and unchanged until xClose() is 965 ** called. Because of the previous sentence, 966 ** the [sqlite3_file] can safely store a pointer to the 967 ** filename if it needs to remember the filename for some reason. 968 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen 969 ** must invent its own temporary name for the file. ^Whenever the 970 ** xFilename parameter is NULL it will also be the case that the 971 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 972 ** 973 ** The flags argument to xOpen() includes all bits set in 974 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 975 ** or [sqlite3_open16()] is used, then flags includes at least 976 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 977 ** If xOpen() opens a file read-only then it sets *pOutFlags to 978 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 979 ** 980 ** ^(SQLite will also add one of the following flags to the xOpen() 981 ** call, depending on the object being opened: 982 ** 983 ** <ul> 984 ** <li> [SQLITE_OPEN_MAIN_DB] 985 ** <li> [SQLITE_OPEN_MAIN_JOURNAL] 986 ** <li> [SQLITE_OPEN_TEMP_DB] 987 ** <li> [SQLITE_OPEN_TEMP_JOURNAL] 988 ** <li> [SQLITE_OPEN_TRANSIENT_DB] 989 ** <li> [SQLITE_OPEN_SUBJOURNAL] 990 ** <li> [SQLITE_OPEN_MASTER_JOURNAL] 991 ** <li> [SQLITE_OPEN_WAL] 992 ** </ul>)^ 993 ** 994 ** The file I/O implementation can use the object type flags to 995 ** change the way it deals with files. For example, an application 996 ** that does not care about crash recovery or rollback might make 997 ** the open of a journal file a no-op. Writes to this journal would 998 ** also be no-ops, and any attempt to read the journal would return 999 ** SQLITE_IOERR. Or the implementation might recognize that a database 1000 ** file will be doing page-aligned sector reads and writes in a random 1001 ** order and set up its I/O subsystem accordingly. 1002 ** 1003 ** SQLite might also add one of the following flags to the xOpen method: 1004 ** 1005 ** <ul> 1006 ** <li> [SQLITE_OPEN_DELETEONCLOSE] 1007 ** <li> [SQLITE_OPEN_EXCLUSIVE] 1008 ** </ul> 1009 ** 1010 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1011 ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1012 ** will be set for TEMP databases and their journals, transient 1013 ** databases, and subjournals. 1014 ** 1015 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1016 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1017 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1018 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1019 ** SQLITE_OPEN_CREATE, is used to indicate that file should always 1020 ** be created, and that it is an error if it already exists. 1021 ** It is <i>not</i> used to indicate the file should be opened 1022 ** for exclusive access. 1023 ** 1024 ** ^At least szOsFile bytes of memory are allocated by SQLite 1025 ** to hold the [sqlite3_file] structure passed as the third 1026 ** argument to xOpen. The xOpen method does not have to 1027 ** allocate the structure; it should just fill it in. Note that 1028 ** the xOpen method must set the sqlite3_file.pMethods to either 1029 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1030 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1031 ** element will be valid after xOpen returns regardless of the success 1032 ** or failure of the xOpen call. 1033 ** 1034 ** [[sqlite3_vfs.xAccess]] 1035 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1036 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1037 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1038 ** to test whether a file is at least readable. The file can be a 1039 ** directory. 1040 ** 1041 ** ^SQLite will always allocate at least mxPathname+1 bytes for the 1042 ** output buffer xFullPathname. The exact size of the output buffer 1043 ** is also passed as a parameter to both methods. If the output buffer 1044 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1045 ** handled as a fatal error by SQLite, vfs implementations should endeavor 1046 ** to prevent this by setting mxPathname to a sufficiently large value. 1047 ** 1048 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1049 ** interfaces are not strictly a part of the filesystem, but they are 1050 ** included in the VFS structure for completeness. 1051 ** The xRandomness() function attempts to return nBytes bytes 1052 ** of good-quality randomness into zOut. The return value is 1053 ** the actual number of bytes of randomness obtained. 1054 ** The xSleep() method causes the calling thread to sleep for at 1055 ** least the number of microseconds given. ^The xCurrentTime() 1056 ** method returns a Julian Day Number for the current date and time as 1057 ** a floating point value. 1058 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1059 ** Day Number multiplied by 86400000 (the number of milliseconds in 1060 ** a 24-hour day). 1061 ** ^SQLite will use the xCurrentTimeInt64() method to get the current 1062 ** date and time if that method is available (if iVersion is 2 or 1063 ** greater and the function pointer is not NULL) and will fall back 1064 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1065 ** 1066 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1067 ** are not used by the SQLite core. These optional interfaces are provided 1068 ** by some VFSes to facilitate testing of the VFS code. By overriding 1069 ** system calls with functions under its control, a test program can 1070 ** simulate faults and error conditions that would otherwise be difficult 1071 ** or impossible to induce. The set of system calls that can be overridden 1072 ** varies from one VFS to another, and from one version of the same VFS to the 1073 ** next. Applications that use these interfaces must be prepared for any 1074 ** or all of these interfaces to be NULL or for their behavior to change 1075 ** from one release to the next. Applications must not attempt to access 1076 ** any of these methods if the iVersion of the VFS is less than 3. 1077 */ 1078 typedef struct sqlite3_vfs sqlite3_vfs; 1079 typedef void (*sqlite3_syscall_ptr)(void); 1080 struct sqlite3_vfs { 1081 int iVersion; /* Structure version number (currently 3) */ 1082 int szOsFile; /* Size of subclassed sqlite3_file */ 1083 int mxPathname; /* Maximum file pathname length */ 1084 sqlite3_vfs *pNext; /* Next registered VFS */ 1085 const char *zName; /* Name of this virtual file system */ 1086 void *pAppData; /* Pointer to application-specific data */ 1087 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1088 int flags, int *pOutFlags); 1089 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1090 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1091 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1092 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1093 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1094 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1095 void (*xDlClose)(sqlite3_vfs*, void*); 1096 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1097 int (*xSleep)(sqlite3_vfs*, int microseconds); 1098 int (*xCurrentTime)(sqlite3_vfs*, double*); 1099 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1100 /* 1101 ** The methods above are in version 1 of the sqlite_vfs object 1102 ** definition. Those that follow are added in version 2 or later 1103 */ 1104 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1105 /* 1106 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1107 ** Those below are for version 3 and greater. 1108 */ 1109 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1110 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1111 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1112 /* 1113 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1114 ** New fields may be appended in figure versions. The iVersion 1115 ** value will increment whenever this happens. 1116 */ 1117 }; 1118 1119 /* 1120 ** CAPI3REF: Flags for the xAccess VFS method 1121 ** 1122 ** These integer constants can be used as the third parameter to 1123 ** the xAccess method of an [sqlite3_vfs] object. They determine 1124 ** what kind of permissions the xAccess method is looking for. 1125 ** With SQLITE_ACCESS_EXISTS, the xAccess method 1126 ** simply checks whether the file exists. 1127 ** With SQLITE_ACCESS_READWRITE, the xAccess method 1128 ** checks whether the named directory is both readable and writable 1129 ** (in other words, if files can be added, removed, and renamed within 1130 ** the directory). 1131 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1132 ** [temp_store_directory pragma], though this could change in a future 1133 ** release of SQLite. 1134 ** With SQLITE_ACCESS_READ, the xAccess method 1135 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1136 ** currently unused, though it might be used in a future release of 1137 ** SQLite. 1138 */ 1139 #define SQLITE_ACCESS_EXISTS 0 1140 #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1141 #define SQLITE_ACCESS_READ 2 /* Unused */ 1142 1143 /* 1144 ** CAPI3REF: Flags for the xShmLock VFS method 1145 ** 1146 ** These integer constants define the various locking operations 1147 ** allowed by the xShmLock method of [sqlite3_io_methods]. The 1148 ** following are the only legal combinations of flags to the 1149 ** xShmLock method: 1150 ** 1151 ** <ul> 1152 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1153 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1154 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1155 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1156 ** </ul> 1157 ** 1158 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1159 ** was given no the corresponding lock. 1160 ** 1161 ** The xShmLock method can transition between unlocked and SHARED or 1162 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1163 ** and EXCLUSIVE. 1164 */ 1165 #define SQLITE_SHM_UNLOCK 1 1166 #define SQLITE_SHM_LOCK 2 1167 #define SQLITE_SHM_SHARED 4 1168 #define SQLITE_SHM_EXCLUSIVE 8 1169 1170 /* 1171 ** CAPI3REF: Maximum xShmLock index 1172 ** 1173 ** The xShmLock method on [sqlite3_io_methods] may use values 1174 ** between 0 and this upper bound as its "offset" argument. 1175 ** The SQLite core will never attempt to acquire or release a 1176 ** lock outside of this range 1177 */ 1178 #define SQLITE_SHM_NLOCK 8 1179 1180 1181 /* 1182 ** CAPI3REF: Initialize The SQLite Library 1183 ** 1184 ** ^The sqlite3_initialize() routine initializes the 1185 ** SQLite library. ^The sqlite3_shutdown() routine 1186 ** deallocates any resources that were allocated by sqlite3_initialize(). 1187 ** These routines are designed to aid in process initialization and 1188 ** shutdown on embedded systems. Workstation applications using 1189 ** SQLite normally do not need to invoke either of these routines. 1190 ** 1191 ** A call to sqlite3_initialize() is an "effective" call if it is 1192 ** the first time sqlite3_initialize() is invoked during the lifetime of 1193 ** the process, or if it is the first time sqlite3_initialize() is invoked 1194 ** following a call to sqlite3_shutdown(). ^(Only an effective call 1195 ** of sqlite3_initialize() does any initialization. All other calls 1196 ** are harmless no-ops.)^ 1197 ** 1198 ** A call to sqlite3_shutdown() is an "effective" call if it is the first 1199 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1200 ** an effective call to sqlite3_shutdown() does any deinitialization. 1201 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1202 ** 1203 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1204 ** is not. The sqlite3_shutdown() interface must only be called from a 1205 ** single thread. All open [database connections] must be closed and all 1206 ** other SQLite resources must be deallocated prior to invoking 1207 ** sqlite3_shutdown(). 1208 ** 1209 ** Among other things, ^sqlite3_initialize() will invoke 1210 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1211 ** will invoke sqlite3_os_end(). 1212 ** 1213 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1214 ** ^If for some reason, sqlite3_initialize() is unable to initialize 1215 ** the library (perhaps it is unable to allocate a needed resource such 1216 ** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1217 ** 1218 ** ^The sqlite3_initialize() routine is called internally by many other 1219 ** SQLite interfaces so that an application usually does not need to 1220 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1221 ** calls sqlite3_initialize() so the SQLite library will be automatically 1222 ** initialized when [sqlite3_open()] is called if it has not be initialized 1223 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1224 ** compile-time option, then the automatic calls to sqlite3_initialize() 1225 ** are omitted and the application must call sqlite3_initialize() directly 1226 ** prior to using any other SQLite interface. For maximum portability, 1227 ** it is recommended that applications always invoke sqlite3_initialize() 1228 ** directly prior to using any other SQLite interface. Future releases 1229 ** of SQLite may require this. In other words, the behavior exhibited 1230 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1231 ** default behavior in some future release of SQLite. 1232 ** 1233 ** The sqlite3_os_init() routine does operating-system specific 1234 ** initialization of the SQLite library. The sqlite3_os_end() 1235 ** routine undoes the effect of sqlite3_os_init(). Typical tasks 1236 ** performed by these routines include allocation or deallocation 1237 ** of static resources, initialization of global variables, 1238 ** setting up a default [sqlite3_vfs] module, or setting up 1239 ** a default configuration using [sqlite3_config()]. 1240 ** 1241 ** The application should never invoke either sqlite3_os_init() 1242 ** or sqlite3_os_end() directly. The application should only invoke 1243 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1244 ** interface is called automatically by sqlite3_initialize() and 1245 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1246 ** implementations for sqlite3_os_init() and sqlite3_os_end() 1247 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1248 ** When [custom builds | built for other platforms] 1249 ** (using the [SQLITE_OS_OTHER=1] compile-time 1250 ** option) the application must supply a suitable implementation for 1251 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1252 ** implementation of sqlite3_os_init() or sqlite3_os_end() 1253 ** must return [SQLITE_OK] on success and some other [error code] upon 1254 ** failure. 1255 */ 1256 SQLITE_API int sqlite3_initialize(void); 1257 SQLITE_API int sqlite3_shutdown(void); 1258 SQLITE_API int sqlite3_os_init(void); 1259 SQLITE_API int sqlite3_os_end(void); 1260 1261 /* 1262 ** CAPI3REF: Configuring The SQLite Library 1263 ** 1264 ** The sqlite3_config() interface is used to make global configuration 1265 ** changes to SQLite in order to tune SQLite to the specific needs of 1266 ** the application. The default configuration is recommended for most 1267 ** applications and so this routine is usually not necessary. It is 1268 ** provided to support rare applications with unusual needs. 1269 ** 1270 ** The sqlite3_config() interface is not threadsafe. The application 1271 ** must insure that no other SQLite interfaces are invoked by other 1272 ** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1273 ** may only be invoked prior to library initialization using 1274 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1275 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1276 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1277 ** Note, however, that ^sqlite3_config() can be called as part of the 1278 ** implementation of an application-defined [sqlite3_os_init()]. 1279 ** 1280 ** The first argument to sqlite3_config() is an integer 1281 ** [configuration option] that determines 1282 ** what property of SQLite is to be configured. Subsequent arguments 1283 ** vary depending on the [configuration option] 1284 ** in the first argument. 1285 ** 1286 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1287 ** ^If the option is unknown or SQLite is unable to set the option 1288 ** then this routine returns a non-zero [error code]. 1289 */ 1290 SQLITE_API int sqlite3_config(int, ...); 1291 1292 /* 1293 ** CAPI3REF: Configure database connections 1294 ** 1295 ** The sqlite3_db_config() interface is used to make configuration 1296 ** changes to a [database connection]. The interface is similar to 1297 ** [sqlite3_config()] except that the changes apply to a single 1298 ** [database connection] (specified in the first argument). 1299 ** 1300 ** The second argument to sqlite3_db_config(D,V,...) is the 1301 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1302 ** that indicates what aspect of the [database connection] is being configured. 1303 ** Subsequent arguments vary depending on the configuration verb. 1304 ** 1305 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1306 ** the call is considered successful. 1307 */ 1308 SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...); 1309 1310 /* 1311 ** CAPI3REF: Memory Allocation Routines 1312 ** 1313 ** An instance of this object defines the interface between SQLite 1314 ** and low-level memory allocation routines. 1315 ** 1316 ** This object is used in only one place in the SQLite interface. 1317 ** A pointer to an instance of this object is the argument to 1318 ** [sqlite3_config()] when the configuration option is 1319 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1320 ** By creating an instance of this object 1321 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1322 ** during configuration, an application can specify an alternative 1323 ** memory allocation subsystem for SQLite to use for all of its 1324 ** dynamic memory needs. 1325 ** 1326 ** Note that SQLite comes with several [built-in memory allocators] 1327 ** that are perfectly adequate for the overwhelming majority of applications 1328 ** and that this object is only useful to a tiny minority of applications 1329 ** with specialized memory allocation requirements. This object is 1330 ** also used during testing of SQLite in order to specify an alternative 1331 ** memory allocator that simulates memory out-of-memory conditions in 1332 ** order to verify that SQLite recovers gracefully from such 1333 ** conditions. 1334 ** 1335 ** The xMalloc, xRealloc, and xFree methods must work like the 1336 ** malloc(), realloc() and free() functions from the standard C library. 1337 ** ^SQLite guarantees that the second argument to 1338 ** xRealloc is always a value returned by a prior call to xRoundup. 1339 ** 1340 ** xSize should return the allocated size of a memory allocation 1341 ** previously obtained from xMalloc or xRealloc. The allocated size 1342 ** is always at least as big as the requested size but may be larger. 1343 ** 1344 ** The xRoundup method returns what would be the allocated size of 1345 ** a memory allocation given a particular requested size. Most memory 1346 ** allocators round up memory allocations at least to the next multiple 1347 ** of 8. Some allocators round up to a larger multiple or to a power of 2. 1348 ** Every memory allocation request coming in through [sqlite3_malloc()] 1349 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1350 ** that causes the corresponding memory allocation to fail. 1351 ** 1352 ** The xInit method initializes the memory allocator. (For example, 1353 ** it might allocate any require mutexes or initialize internal data 1354 ** structures. The xShutdown method is invoked (indirectly) by 1355 ** [sqlite3_shutdown()] and should deallocate any resources acquired 1356 ** by xInit. The pAppData pointer is used as the only parameter to 1357 ** xInit and xShutdown. 1358 ** 1359 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1360 ** the xInit method, so the xInit method need not be threadsafe. The 1361 ** xShutdown method is only called from [sqlite3_shutdown()] so it does 1362 ** not need to be threadsafe either. For all other methods, SQLite 1363 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1364 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1365 ** it is by default) and so the methods are automatically serialized. 1366 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1367 ** methods must be threadsafe or else make their own arrangements for 1368 ** serialization. 1369 ** 1370 ** SQLite will never invoke xInit() more than once without an intervening 1371 ** call to xShutdown(). 1372 */ 1373 typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1374 struct sqlite3_mem_methods { 1375 void *(*xMalloc)(int); /* Memory allocation function */ 1376 void (*xFree)(void*); /* Free a prior allocation */ 1377 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1378 int (*xSize)(void*); /* Return the size of an allocation */ 1379 int (*xRoundup)(int); /* Round up request size to allocation size */ 1380 int (*xInit)(void*); /* Initialize the memory allocator */ 1381 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1382 void *pAppData; /* Argument to xInit() and xShutdown() */ 1383 }; 1384 1385 /* 1386 ** CAPI3REF: Configuration Options 1387 ** KEYWORDS: {configuration option} 1388 ** 1389 ** These constants are the available integer configuration options that 1390 ** can be passed as the first argument to the [sqlite3_config()] interface. 1391 ** 1392 ** New configuration options may be added in future releases of SQLite. 1393 ** Existing configuration options might be discontinued. Applications 1394 ** should check the return code from [sqlite3_config()] to make sure that 1395 ** the call worked. The [sqlite3_config()] interface will return a 1396 ** non-zero [error code] if a discontinued or unsupported configuration option 1397 ** is invoked. 1398 ** 1399 ** <dl> 1400 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1401 ** <dd>There are no arguments to this option. ^This option sets the 1402 ** [threading mode] to Single-thread. In other words, it disables 1403 ** all mutexing and puts SQLite into a mode where it can only be used 1404 ** by a single thread. ^If SQLite is compiled with 1405 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1406 ** it is not possible to change the [threading mode] from its default 1407 ** value of Single-thread and so [sqlite3_config()] will return 1408 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1409 ** configuration option.</dd> 1410 ** 1411 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1412 ** <dd>There are no arguments to this option. ^This option sets the 1413 ** [threading mode] to Multi-thread. In other words, it disables 1414 ** mutexing on [database connection] and [prepared statement] objects. 1415 ** The application is responsible for serializing access to 1416 ** [database connections] and [prepared statements]. But other mutexes 1417 ** are enabled so that SQLite will be safe to use in a multi-threaded 1418 ** environment as long as no two threads attempt to use the same 1419 ** [database connection] at the same time. ^If SQLite is compiled with 1420 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1421 ** it is not possible to set the Multi-thread [threading mode] and 1422 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1423 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1424 ** 1425 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1426 ** <dd>There are no arguments to this option. ^This option sets the 1427 ** [threading mode] to Serialized. In other words, this option enables 1428 ** all mutexes including the recursive 1429 ** mutexes on [database connection] and [prepared statement] objects. 1430 ** In this mode (which is the default when SQLite is compiled with 1431 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1432 ** to [database connections] and [prepared statements] so that the 1433 ** application is free to use the same [database connection] or the 1434 ** same [prepared statement] in different threads at the same time. 1435 ** ^If SQLite is compiled with 1436 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1437 ** it is not possible to set the Serialized [threading mode] and 1438 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1439 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1440 ** 1441 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1442 ** <dd> ^(This option takes a single argument which is a pointer to an 1443 ** instance of the [sqlite3_mem_methods] structure. The argument specifies 1444 ** alternative low-level memory allocation routines to be used in place of 1445 ** the memory allocation routines built into SQLite.)^ ^SQLite makes 1446 ** its own private copy of the content of the [sqlite3_mem_methods] structure 1447 ** before the [sqlite3_config()] call returns.</dd> 1448 ** 1449 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1450 ** <dd> ^(This option takes a single argument which is a pointer to an 1451 ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1452 ** structure is filled with the currently defined memory allocation routines.)^ 1453 ** This option can be used to overload the default memory allocation 1454 ** routines with a wrapper that simulations memory allocation failure or 1455 ** tracks memory usage, for example. </dd> 1456 ** 1457 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1458 ** <dd> ^This option takes single argument of type int, interpreted as a 1459 ** boolean, which enables or disables the collection of memory allocation 1460 ** statistics. ^(When memory allocation statistics are disabled, the 1461 ** following SQLite interfaces become non-operational: 1462 ** <ul> 1463 ** <li> [sqlite3_memory_used()] 1464 ** <li> [sqlite3_memory_highwater()] 1465 ** <li> [sqlite3_soft_heap_limit64()] 1466 ** <li> [sqlite3_status()] 1467 ** </ul>)^ 1468 ** ^Memory allocation statistics are enabled by default unless SQLite is 1469 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1470 ** allocation statistics are disabled by default. 1471 ** </dd> 1472 ** 1473 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1474 ** <dd> ^This option specifies a static memory buffer that SQLite can use for 1475 ** scratch memory. There are three arguments: A pointer an 8-byte 1476 ** aligned memory buffer from which the scratch allocations will be 1477 ** drawn, the size of each scratch allocation (sz), 1478 ** and the maximum number of scratch allocations (N). The sz 1479 ** argument must be a multiple of 16. 1480 ** The first argument must be a pointer to an 8-byte aligned buffer 1481 ** of at least sz*N bytes of memory. 1482 ** ^SQLite will use no more than two scratch buffers per thread. So 1483 ** N should be set to twice the expected maximum number of threads. 1484 ** ^SQLite will never require a scratch buffer that is more than 6 1485 ** times the database page size. ^If SQLite needs needs additional 1486 ** scratch memory beyond what is provided by this configuration option, then 1487 ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1488 ** 1489 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1490 ** <dd> ^This option specifies a static memory buffer that SQLite can use for 1491 ** the database page cache with the default page cache implementation. 1492 ** This configuration should not be used if an application-define page 1493 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option. 1494 ** There are three arguments to this option: A pointer to 8-byte aligned 1495 ** memory, the size of each page buffer (sz), and the number of pages (N). 1496 ** The sz argument should be the size of the largest database page 1497 ** (a power of two between 512 and 32768) plus a little extra for each 1498 ** page header. ^The page header size is 20 to 40 bytes depending on 1499 ** the host architecture. ^It is harmless, apart from the wasted memory, 1500 ** to make sz a little too large. The first 1501 ** argument should point to an allocation of at least sz*N bytes of memory. 1502 ** ^SQLite will use the memory provided by the first argument to satisfy its 1503 ** memory needs for the first N pages that it adds to cache. ^If additional 1504 ** page cache memory is needed beyond what is provided by this option, then 1505 ** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1506 ** The pointer in the first argument must 1507 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1508 ** will be undefined.</dd> 1509 ** 1510 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1511 ** <dd> ^This option specifies a static memory buffer that SQLite will use 1512 ** for all of its dynamic memory allocation needs beyond those provided 1513 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1514 ** There are three arguments: An 8-byte aligned pointer to the memory, 1515 ** the number of bytes in the memory buffer, and the minimum allocation size. 1516 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1517 ** to using its default memory allocator (the system malloc() implementation), 1518 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1519 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1520 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1521 ** allocator is engaged to handle all of SQLites memory allocation needs. 1522 ** The first pointer (the memory pointer) must be aligned to an 8-byte 1523 ** boundary or subsequent behavior of SQLite will be undefined. 1524 ** The minimum allocation size is capped at 2**12. Reasonable values 1525 ** for the minimum allocation size are 2**5 through 2**8.</dd> 1526 ** 1527 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1528 ** <dd> ^(This option takes a single argument which is a pointer to an 1529 ** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1530 ** alternative low-level mutex routines to be used in place 1531 ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1532 ** content of the [sqlite3_mutex_methods] structure before the call to 1533 ** [sqlite3_config()] returns. ^If SQLite is compiled with 1534 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1535 ** the entire mutexing subsystem is omitted from the build and hence calls to 1536 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1537 ** return [SQLITE_ERROR].</dd> 1538 ** 1539 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1540 ** <dd> ^(This option takes a single argument which is a pointer to an 1541 ** instance of the [sqlite3_mutex_methods] structure. The 1542 ** [sqlite3_mutex_methods] 1543 ** structure is filled with the currently defined mutex routines.)^ 1544 ** This option can be used to overload the default mutex allocation 1545 ** routines with a wrapper used to track mutex usage for performance 1546 ** profiling or testing, for example. ^If SQLite is compiled with 1547 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1548 ** the entire mutexing subsystem is omitted from the build and hence calls to 1549 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1550 ** return [SQLITE_ERROR].</dd> 1551 ** 1552 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1553 ** <dd> ^(This option takes two arguments that determine the default 1554 ** memory allocation for the lookaside memory allocator on each 1555 ** [database connection]. The first argument is the 1556 ** size of each lookaside buffer slot and the second is the number of 1557 ** slots allocated to each database connection.)^ ^(This option sets the 1558 ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1559 ** verb to [sqlite3_db_config()] can be used to change the lookaside 1560 ** configuration on individual connections.)^ </dd> 1561 ** 1562 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1563 ** <dd> ^(This option takes a single argument which is a pointer to 1564 ** an [sqlite3_pcache_methods2] object. This object specifies the interface 1565 ** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1566 ** object and uses it for page cache memory allocations.</dd> 1567 ** 1568 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1569 ** <dd> ^(This option takes a single argument which is a pointer to an 1570 ** [sqlite3_pcache_methods2] object. SQLite copies of the current 1571 ** page cache implementation into that object.)^ </dd> 1572 ** 1573 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1574 ** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1575 ** function with a call signature of void(*)(void*,int,const char*), 1576 ** and a pointer to void. ^If the function pointer is not NULL, it is 1577 ** invoked by [sqlite3_log()] to process each logging event. ^If the 1578 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1579 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1580 ** passed through as the first parameter to the application-defined logger 1581 ** function whenever that function is invoked. ^The second parameter to 1582 ** the logger function is a copy of the first parameter to the corresponding 1583 ** [sqlite3_log()] call and is intended to be a [result code] or an 1584 ** [extended result code]. ^The third parameter passed to the logger is 1585 ** log message after formatting via [sqlite3_snprintf()]. 1586 ** The SQLite logging interface is not reentrant; the logger function 1587 ** supplied by the application must not invoke any SQLite interface. 1588 ** In a multi-threaded application, the application-defined logger 1589 ** function must be threadsafe. </dd> 1590 ** 1591 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1592 ** <dd> This option takes a single argument of type int. If non-zero, then 1593 ** URI handling is globally enabled. If the parameter is zero, then URI handling 1594 ** is globally disabled. If URI handling is globally enabled, all filenames 1595 ** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or 1596 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1597 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1598 ** connection is opened. If it is globally disabled, filenames are 1599 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1600 ** database connection is opened. By default, URI handling is globally 1601 ** disabled. The default value may be changed by compiling with the 1602 ** [SQLITE_USE_URI] symbol defined. 1603 ** 1604 ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1605 ** <dd> This option takes a single integer argument which is interpreted as 1606 ** a boolean in order to enable or disable the use of covering indices for 1607 ** full table scans in the query optimizer. The default setting is determined 1608 ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1609 ** if that compile-time option is omitted. 1610 ** The ability to disable the use of covering indices for full table scans 1611 ** is because some incorrectly coded legacy applications might malfunction 1612 ** malfunction when the optimization is enabled. Providing the ability to 1613 ** disable the optimization allows the older, buggy application code to work 1614 ** without change even with newer versions of SQLite. 1615 ** 1616 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1617 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1618 ** <dd> These options are obsolete and should not be used by new code. 1619 ** They are retained for backwards compatibility but are now no-ops. 1620 ** </dl> 1621 ** 1622 ** [[SQLITE_CONFIG_SQLLOG]] 1623 ** <dt>SQLITE_CONFIG_SQLLOG 1624 ** <dd>This option is only available if sqlite is compiled with the 1625 ** SQLITE_ENABLE_SQLLOG pre-processor macro defined. The first argument should 1626 ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1627 ** The second should be of type (void*). The callback is invoked by the library 1628 ** in three separate circumstances, identified by the value passed as the 1629 ** fourth parameter. If the fourth parameter is 0, then the database connection 1630 ** passed as the second argument has just been opened. The third argument 1631 ** points to a buffer containing the name of the main database file. If the 1632 ** fourth parameter is 1, then the SQL statement that the third parameter 1633 ** points to has just been executed. Or, if the fourth parameter is 2, then 1634 ** the connection being passed as the second parameter is being closed. The 1635 ** third parameter is passed NULL In this case. 1636 ** </dl> 1637 */ 1638 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1639 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1640 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1641 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1642 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1643 #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1644 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1645 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1646 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1647 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1648 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1649 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1650 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1651 #define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1652 #define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1653 #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1654 #define SQLITE_CONFIG_URI 17 /* int */ 1655 #define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1656 #define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1657 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1658 #define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1659 1660 /* 1661 ** CAPI3REF: Database Connection Configuration Options 1662 ** 1663 ** These constants are the available integer configuration options that 1664 ** can be passed as the second argument to the [sqlite3_db_config()] interface. 1665 ** 1666 ** New configuration options may be added in future releases of SQLite. 1667 ** Existing configuration options might be discontinued. Applications 1668 ** should check the return code from [sqlite3_db_config()] to make sure that 1669 ** the call worked. ^The [sqlite3_db_config()] interface will return a 1670 ** non-zero [error code] if a discontinued or unsupported configuration option 1671 ** is invoked. 1672 ** 1673 ** <dl> 1674 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1675 ** <dd> ^This option takes three additional arguments that determine the 1676 ** [lookaside memory allocator] configuration for the [database connection]. 1677 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1678 ** pointer to a memory buffer to use for lookaside memory. 1679 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1680 ** may be NULL in which case SQLite will allocate the 1681 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1682 ** size of each lookaside buffer slot. ^The third argument is the number of 1683 ** slots. The size of the buffer in the first argument must be greater than 1684 ** or equal to the product of the second and third arguments. The buffer 1685 ** must be aligned to an 8-byte boundary. ^If the second argument to 1686 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1687 ** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1688 ** configuration for a database connection can only be changed when that 1689 ** connection is not currently using lookaside memory, or in other words 1690 ** when the "current value" returned by 1691 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1692 ** Any attempt to change the lookaside memory configuration when lookaside 1693 ** memory is in use leaves the configuration unchanged and returns 1694 ** [SQLITE_BUSY].)^</dd> 1695 ** 1696 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1697 ** <dd> ^This option is used to enable or disable the enforcement of 1698 ** [foreign key constraints]. There should be two additional arguments. 1699 ** The first argument is an integer which is 0 to disable FK enforcement, 1700 ** positive to enable FK enforcement or negative to leave FK enforcement 1701 ** unchanged. The second parameter is a pointer to an integer into which 1702 ** is written 0 or 1 to indicate whether FK enforcement is off or on 1703 ** following this call. The second parameter may be a NULL pointer, in 1704 ** which case the FK enforcement setting is not reported back. </dd> 1705 ** 1706 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1707 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1708 ** There should be two additional arguments. 1709 ** The first argument is an integer which is 0 to disable triggers, 1710 ** positive to enable triggers or negative to leave the setting unchanged. 1711 ** The second parameter is a pointer to an integer into which 1712 ** is written 0 or 1 to indicate whether triggers are disabled or enabled 1713 ** following this call. The second parameter may be a NULL pointer, in 1714 ** which case the trigger setting is not reported back. </dd> 1715 ** 1716 ** </dl> 1717 */ 1718 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1719 #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1720 #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1721 1722 1723 /* 1724 ** CAPI3REF: Enable Or Disable Extended Result Codes 1725 ** 1726 ** ^The sqlite3_extended_result_codes() routine enables or disables the 1727 ** [extended result codes] feature of SQLite. ^The extended result 1728 ** codes are disabled by default for historical compatibility. 1729 */ 1730 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff); 1731 1732 /* 1733 ** CAPI3REF: Last Insert Rowid 1734 ** 1735 ** ^Each entry in an SQLite table has a unique 64-bit signed 1736 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1737 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1738 ** names are not also used by explicitly declared columns. ^If 1739 ** the table has a column of type [INTEGER PRIMARY KEY] then that column 1740 ** is another alias for the rowid. 1741 ** 1742 ** ^This routine returns the [rowid] of the most recent 1743 ** successful [INSERT] into the database from the [database connection] 1744 ** in the first argument. ^As of SQLite version 3.7.7, this routines 1745 ** records the last insert rowid of both ordinary tables and [virtual tables]. 1746 ** ^If no successful [INSERT]s 1747 ** have ever occurred on that database connection, zero is returned. 1748 ** 1749 ** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1750 ** method, then this routine will return the [rowid] of the inserted 1751 ** row as long as the trigger or virtual table method is running. 1752 ** But once the trigger or virtual table method ends, the value returned 1753 ** by this routine reverts to what it was before the trigger or virtual 1754 ** table method began.)^ 1755 ** 1756 ** ^An [INSERT] that fails due to a constraint violation is not a 1757 ** successful [INSERT] and does not change the value returned by this 1758 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1759 ** and INSERT OR ABORT make no changes to the return value of this 1760 ** routine when their insertion fails. ^(When INSERT OR REPLACE 1761 ** encounters a constraint violation, it does not fail. The 1762 ** INSERT continues to completion after deleting rows that caused 1763 ** the constraint problem so INSERT OR REPLACE will always change 1764 ** the return value of this interface.)^ 1765 ** 1766 ** ^For the purposes of this routine, an [INSERT] is considered to 1767 ** be successful even if it is subsequently rolled back. 1768 ** 1769 ** This function is accessible to SQL statements via the 1770 ** [last_insert_rowid() SQL function]. 1771 ** 1772 ** If a separate thread performs a new [INSERT] on the same 1773 ** database connection while the [sqlite3_last_insert_rowid()] 1774 ** function is running and thus changes the last insert [rowid], 1775 ** then the value returned by [sqlite3_last_insert_rowid()] is 1776 ** unpredictable and might not equal either the old or the new 1777 ** last insert [rowid]. 1778 */ 1779 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1780 1781 /* 1782 ** CAPI3REF: Count The Number Of Rows Modified 1783 ** 1784 ** ^This function returns the number of database rows that were changed 1785 ** or inserted or deleted by the most recently completed SQL statement 1786 ** on the [database connection] specified by the first parameter. 1787 ** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1788 ** or [DELETE] statement are counted. Auxiliary changes caused by 1789 ** triggers or [foreign key actions] are not counted.)^ Use the 1790 ** [sqlite3_total_changes()] function to find the total number of changes 1791 ** including changes caused by triggers and foreign key actions. 1792 ** 1793 ** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1794 ** are not counted. Only real table changes are counted. 1795 ** 1796 ** ^(A "row change" is a change to a single row of a single table 1797 ** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1798 ** are changed as side effects of [REPLACE] constraint resolution, 1799 ** rollback, ABORT processing, [DROP TABLE], or by any other 1800 ** mechanisms do not count as direct row changes.)^ 1801 ** 1802 ** A "trigger context" is a scope of execution that begins and 1803 ** ends with the script of a [CREATE TRIGGER | trigger]. 1804 ** Most SQL statements are 1805 ** evaluated outside of any trigger. This is the "top level" 1806 ** trigger context. If a trigger fires from the top level, a 1807 ** new trigger context is entered for the duration of that one 1808 ** trigger. Subtriggers create subcontexts for their duration. 1809 ** 1810 ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1811 ** not create a new trigger context. 1812 ** 1813 ** ^This function returns the number of direct row changes in the 1814 ** most recent INSERT, UPDATE, or DELETE statement within the same 1815 ** trigger context. 1816 ** 1817 ** ^Thus, when called from the top level, this function returns the 1818 ** number of changes in the most recent INSERT, UPDATE, or DELETE 1819 ** that also occurred at the top level. ^(Within the body of a trigger, 1820 ** the sqlite3_changes() interface can be called to find the number of 1821 ** changes in the most recently completed INSERT, UPDATE, or DELETE 1822 ** statement within the body of the same trigger. 1823 ** However, the number returned does not include changes 1824 ** caused by subtriggers since those have their own context.)^ 1825 ** 1826 ** See also the [sqlite3_total_changes()] interface, the 1827 ** [count_changes pragma], and the [changes() SQL function]. 1828 ** 1829 ** If a separate thread makes changes on the same database connection 1830 ** while [sqlite3_changes()] is running then the value returned 1831 ** is unpredictable and not meaningful. 1832 */ 1833 SQLITE_API int sqlite3_changes(sqlite3*); 1834 1835 /* 1836 ** CAPI3REF: Total Number Of Rows Modified 1837 ** 1838 ** ^This function returns the number of row changes caused by [INSERT], 1839 ** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1840 ** ^(The count returned by sqlite3_total_changes() includes all changes 1841 ** from all [CREATE TRIGGER | trigger] contexts and changes made by 1842 ** [foreign key actions]. However, 1843 ** the count does not include changes used to implement [REPLACE] constraints, 1844 ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1845 ** count does not include rows of views that fire an [INSTEAD OF trigger], 1846 ** though if the INSTEAD OF trigger makes changes of its own, those changes 1847 ** are counted.)^ 1848 ** ^The sqlite3_total_changes() function counts the changes as soon as 1849 ** the statement that makes them is completed (when the statement handle 1850 ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1851 ** 1852 ** See also the [sqlite3_changes()] interface, the 1853 ** [count_changes pragma], and the [total_changes() SQL function]. 1854 ** 1855 ** If a separate thread makes changes on the same database connection 1856 ** while [sqlite3_total_changes()] is running then the value 1857 ** returned is unpredictable and not meaningful. 1858 */ 1859 SQLITE_API int sqlite3_total_changes(sqlite3*); 1860 1861 /* 1862 ** CAPI3REF: Interrupt A Long-Running Query 1863 ** 1864 ** ^This function causes any pending database operation to abort and 1865 ** return at its earliest opportunity. This routine is typically 1866 ** called in response to a user action such as pressing "Cancel" 1867 ** or Ctrl-C where the user wants a long query operation to halt 1868 ** immediately. 1869 ** 1870 ** ^It is safe to call this routine from a thread different from the 1871 ** thread that is currently running the database operation. But it 1872 ** is not safe to call this routine with a [database connection] that 1873 ** is closed or might close before sqlite3_interrupt() returns. 1874 ** 1875 ** ^If an SQL operation is very nearly finished at the time when 1876 ** sqlite3_interrupt() is called, then it might not have an opportunity 1877 ** to be interrupted and might continue to completion. 1878 ** 1879 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1880 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1881 ** that is inside an explicit transaction, then the entire transaction 1882 ** will be rolled back automatically. 1883 ** 1884 ** ^The sqlite3_interrupt(D) call is in effect until all currently running 1885 ** SQL statements on [database connection] D complete. ^Any new SQL statements 1886 ** that are started after the sqlite3_interrupt() call and before the 1887 ** running statements reaches zero are interrupted as if they had been 1888 ** running prior to the sqlite3_interrupt() call. ^New SQL statements 1889 ** that are started after the running statement count reaches zero are 1890 ** not effected by the sqlite3_interrupt(). 1891 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1892 ** SQL statements is a no-op and has no effect on SQL statements 1893 ** that are started after the sqlite3_interrupt() call returns. 1894 ** 1895 ** If the database connection closes while [sqlite3_interrupt()] 1896 ** is running then bad things will likely happen. 1897 */ 1898 SQLITE_API void sqlite3_interrupt(sqlite3*); 1899 1900 /* 1901 ** CAPI3REF: Determine If An SQL Statement Is Complete 1902 ** 1903 ** These routines are useful during command-line input to determine if the 1904 ** currently entered text seems to form a complete SQL statement or 1905 ** if additional input is needed before sending the text into 1906 ** SQLite for parsing. ^These routines return 1 if the input string 1907 ** appears to be a complete SQL statement. ^A statement is judged to be 1908 ** complete if it ends with a semicolon token and is not a prefix of a 1909 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1910 ** string literals or quoted identifier names or comments are not 1911 ** independent tokens (they are part of the token in which they are 1912 ** embedded) and thus do not count as a statement terminator. ^Whitespace 1913 ** and comments that follow the final semicolon are ignored. 1914 ** 1915 ** ^These routines return 0 if the statement is incomplete. ^If a 1916 ** memory allocation fails, then SQLITE_NOMEM is returned. 1917 ** 1918 ** ^These routines do not parse the SQL statements thus 1919 ** will not detect syntactically incorrect SQL. 1920 ** 1921 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1922 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1923 ** automatically by sqlite3_complete16(). If that initialization fails, 1924 ** then the return value from sqlite3_complete16() will be non-zero 1925 ** regardless of whether or not the input SQL is complete.)^ 1926 ** 1927 ** The input to [sqlite3_complete()] must be a zero-terminated 1928 ** UTF-8 string. 1929 ** 1930 ** The input to [sqlite3_complete16()] must be a zero-terminated 1931 ** UTF-16 string in native byte order. 1932 */ 1933 SQLITE_API int sqlite3_complete(const char *sql); 1934 SQLITE_API int sqlite3_complete16(const void *sql); 1935 1936 /* 1937 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1938 ** 1939 ** ^This routine sets a callback function that might be invoked whenever 1940 ** an attempt is made to open a database table that another thread 1941 ** or process has locked. 1942 ** 1943 ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1944 ** is returned immediately upon encountering the lock. ^If the busy callback 1945 ** is not NULL, then the callback might be invoked with two arguments. 1946 ** 1947 ** ^The first argument to the busy handler is a copy of the void* pointer which 1948 ** is the third argument to sqlite3_busy_handler(). ^The second argument to 1949 ** the busy handler callback is the number of times that the busy handler has 1950 ** been invoked for this locking event. ^If the 1951 ** busy callback returns 0, then no additional attempts are made to 1952 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1953 ** ^If the callback returns non-zero, then another attempt 1954 ** is made to open the database for reading and the cycle repeats. 1955 ** 1956 ** The presence of a busy handler does not guarantee that it will be invoked 1957 ** when there is lock contention. ^If SQLite determines that invoking the busy 1958 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1959 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1960 ** Consider a scenario where one process is holding a read lock that 1961 ** it is trying to promote to a reserved lock and 1962 ** a second process is holding a reserved lock that it is trying 1963 ** to promote to an exclusive lock. The first process cannot proceed 1964 ** because it is blocked by the second and the second process cannot 1965 ** proceed because it is blocked by the first. If both processes 1966 ** invoke the busy handlers, neither will make any progress. Therefore, 1967 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1968 ** will induce the first process to release its read lock and allow 1969 ** the second process to proceed. 1970 ** 1971 ** ^The default busy callback is NULL. 1972 ** 1973 ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1974 ** when SQLite is in the middle of a large transaction where all the 1975 ** changes will not fit into the in-memory cache. SQLite will 1976 ** already hold a RESERVED lock on the database file, but it needs 1977 ** to promote this lock to EXCLUSIVE so that it can spill cache 1978 ** pages into the database file without harm to concurrent 1979 ** readers. ^If it is unable to promote the lock, then the in-memory 1980 ** cache will be left in an inconsistent state and so the error 1981 ** code is promoted from the relatively benign [SQLITE_BUSY] to 1982 ** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 1983 ** forces an automatic rollback of the changes. See the 1984 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1985 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1986 ** this is important. 1987 ** 1988 ** ^(There can only be a single busy handler defined for each 1989 ** [database connection]. Setting a new busy handler clears any 1990 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 1991 ** will also set or clear the busy handler. 1992 ** 1993 ** The busy callback should not take any actions which modify the 1994 ** database connection that invoked the busy handler. Any such actions 1995 ** result in undefined behavior. 1996 ** 1997 ** A busy handler must not close the database connection 1998 ** or [prepared statement] that invoked the busy handler. 1999 */ 2000 SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 2001 2002 /* 2003 ** CAPI3REF: Set A Busy Timeout 2004 ** 2005 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2006 ** for a specified amount of time when a table is locked. ^The handler 2007 ** will sleep multiple times until at least "ms" milliseconds of sleeping 2008 ** have accumulated. ^After at least "ms" milliseconds of sleeping, 2009 ** the handler returns 0 which causes [sqlite3_step()] to return 2010 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 2011 ** 2012 ** ^Calling this routine with an argument less than or equal to zero 2013 ** turns off all busy handlers. 2014 ** 2015 ** ^(There can only be a single busy handler for a particular 2016 ** [database connection] any any given moment. If another busy handler 2017 ** was defined (using [sqlite3_busy_handler()]) prior to calling 2018 ** this routine, that other busy handler is cleared.)^ 2019 */ 2020 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms); 2021 2022 /* 2023 ** CAPI3REF: Convenience Routines For Running Queries 2024 ** 2025 ** This is a legacy interface that is preserved for backwards compatibility. 2026 ** Use of this interface is not recommended. 2027 ** 2028 ** Definition: A <b>result table</b> is memory data structure created by the 2029 ** [sqlite3_get_table()] interface. A result table records the 2030 ** complete query results from one or more queries. 2031 ** 2032 ** The table conceptually has a number of rows and columns. But 2033 ** these numbers are not part of the result table itself. These 2034 ** numbers are obtained separately. Let N be the number of rows 2035 ** and M be the number of columns. 2036 ** 2037 ** A result table is an array of pointers to zero-terminated UTF-8 strings. 2038 ** There are (N+1)*M elements in the array. The first M pointers point 2039 ** to zero-terminated strings that contain the names of the columns. 2040 ** The remaining entries all point to query results. NULL values result 2041 ** in NULL pointers. All other values are in their UTF-8 zero-terminated 2042 ** string representation as returned by [sqlite3_column_text()]. 2043 ** 2044 ** A result table might consist of one or more memory allocations. 2045 ** It is not safe to pass a result table directly to [sqlite3_free()]. 2046 ** A result table should be deallocated using [sqlite3_free_table()]. 2047 ** 2048 ** ^(As an example of the result table format, suppose a query result 2049 ** is as follows: 2050 ** 2051 ** <blockquote><pre> 2052 ** Name | Age 2053 ** ----------------------- 2054 ** Alice | 43 2055 ** Bob | 28 2056 ** Cindy | 21 2057 ** </pre></blockquote> 2058 ** 2059 ** There are two column (M==2) and three rows (N==3). Thus the 2060 ** result table has 8 entries. Suppose the result table is stored 2061 ** in an array names azResult. Then azResult holds this content: 2062 ** 2063 ** <blockquote><pre> 2064 ** azResult[0] = "Name"; 2065 ** azResult[1] = "Age"; 2066 ** azResult[2] = "Alice"; 2067 ** azResult[3] = "43"; 2068 ** azResult[4] = "Bob"; 2069 ** azResult[5] = "28"; 2070 ** azResult[6] = "Cindy"; 2071 ** azResult[7] = "21"; 2072 ** </pre></blockquote>)^ 2073 ** 2074 ** ^The sqlite3_get_table() function evaluates one or more 2075 ** semicolon-separated SQL statements in the zero-terminated UTF-8 2076 ** string of its 2nd parameter and returns a result table to the 2077 ** pointer given in its 3rd parameter. 2078 ** 2079 ** After the application has finished with the result from sqlite3_get_table(), 2080 ** it must pass the result table pointer to sqlite3_free_table() in order to 2081 ** release the memory that was malloced. Because of the way the 2082 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2083 ** function must not try to call [sqlite3_free()] directly. Only 2084 ** [sqlite3_free_table()] is able to release the memory properly and safely. 2085 ** 2086 ** The sqlite3_get_table() interface is implemented as a wrapper around 2087 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2088 ** to any internal data structures of SQLite. It uses only the public 2089 ** interface defined here. As a consequence, errors that occur in the 2090 ** wrapper layer outside of the internal [sqlite3_exec()] call are not 2091 ** reflected in subsequent calls to [sqlite3_errcode()] or 2092 ** [sqlite3_errmsg()]. 2093 */ 2094 SQLITE_API int sqlite3_get_table( 2095 sqlite3 *db, /* An open database */ 2096 const char *zSql, /* SQL to be evaluated */ 2097 char ***pazResult, /* Results of the query */ 2098 int *pnRow, /* Number of result rows written here */ 2099 int *pnColumn, /* Number of result columns written here */ 2100 char **pzErrmsg /* Error msg written here */ 2101 ); 2102 SQLITE_API void sqlite3_free_table(char **result); 2103 2104 /* 2105 ** CAPI3REF: Formatted String Printing Functions 2106 ** 2107 ** These routines are work-alikes of the "printf()" family of functions 2108 ** from the standard C library. 2109 ** 2110 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2111 ** results into memory obtained from [sqlite3_malloc()]. 2112 ** The strings returned by these two routines should be 2113 ** released by [sqlite3_free()]. ^Both routines return a 2114 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2115 ** memory to hold the resulting string. 2116 ** 2117 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2118 ** the standard C library. The result is written into the 2119 ** buffer supplied as the second parameter whose size is given by 2120 ** the first parameter. Note that the order of the 2121 ** first two parameters is reversed from snprintf().)^ This is an 2122 ** historical accident that cannot be fixed without breaking 2123 ** backwards compatibility. ^(Note also that sqlite3_snprintf() 2124 ** returns a pointer to its buffer instead of the number of 2125 ** characters actually written into the buffer.)^ We admit that 2126 ** the number of characters written would be a more useful return 2127 ** value but we cannot change the implementation of sqlite3_snprintf() 2128 ** now without breaking compatibility. 2129 ** 2130 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2131 ** guarantees that the buffer is always zero-terminated. ^The first 2132 ** parameter "n" is the total size of the buffer, including space for 2133 ** the zero terminator. So the longest string that can be completely 2134 ** written will be n-1 characters. 2135 ** 2136 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2137 ** 2138 ** These routines all implement some additional formatting 2139 ** options that are useful for constructing SQL statements. 2140 ** All of the usual printf() formatting options apply. In addition, there 2141 ** is are "%q", "%Q", and "%z" options. 2142 ** 2143 ** ^(The %q option works like %s in that it substitutes a nul-terminated 2144 ** string from the argument list. But %q also doubles every '\'' character. 2145 ** %q is designed for use inside a string literal.)^ By doubling each '\'' 2146 ** character it escapes that character and allows it to be inserted into 2147 ** the string. 2148 ** 2149 ** For example, assume the string variable zText contains text as follows: 2150 ** 2151 ** <blockquote><pre> 2152 ** char *zText = "It's a happy day!"; 2153 ** </pre></blockquote> 2154 ** 2155 ** One can use this text in an SQL statement as follows: 2156 ** 2157 ** <blockquote><pre> 2158 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2159 ** sqlite3_exec(db, zSQL, 0, 0, 0); 2160 ** sqlite3_free(zSQL); 2161 ** </pre></blockquote> 2162 ** 2163 ** Because the %q format string is used, the '\'' character in zText 2164 ** is escaped and the SQL generated is as follows: 2165 ** 2166 ** <blockquote><pre> 2167 ** INSERT INTO table1 VALUES('It''s a happy day!') 2168 ** </pre></blockquote> 2169 ** 2170 ** This is correct. Had we used %s instead of %q, the generated SQL 2171 ** would have looked like this: 2172 ** 2173 ** <blockquote><pre> 2174 ** INSERT INTO table1 VALUES('It's a happy day!'); 2175 ** </pre></blockquote> 2176 ** 2177 ** This second example is an SQL syntax error. As a general rule you should 2178 ** always use %q instead of %s when inserting text into a string literal. 2179 ** 2180 ** ^(The %Q option works like %q except it also adds single quotes around 2181 ** the outside of the total string. Additionally, if the parameter in the 2182 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2183 ** single quotes).)^ So, for example, one could say: 2184 ** 2185 ** <blockquote><pre> 2186 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2187 ** sqlite3_exec(db, zSQL, 0, 0, 0); 2188 ** sqlite3_free(zSQL); 2189 ** </pre></blockquote> 2190 ** 2191 ** The code above will render a correct SQL statement in the zSQL 2192 ** variable even if the zText variable is a NULL pointer. 2193 ** 2194 ** ^(The "%z" formatting option works like "%s" but with the 2195 ** addition that after the string has been read and copied into 2196 ** the result, [sqlite3_free()] is called on the input string.)^ 2197 */ 2198 SQLITE_API char *sqlite3_mprintf(const char*,...); 2199 SQLITE_API char *sqlite3_vmprintf(const char*, va_list); 2200 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...); 2201 SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2202 2203 /* 2204 ** CAPI3REF: Memory Allocation Subsystem 2205 ** 2206 ** The SQLite core uses these three routines for all of its own 2207 ** internal memory allocation needs. "Core" in the previous sentence 2208 ** does not include operating-system specific VFS implementation. The 2209 ** Windows VFS uses native malloc() and free() for some operations. 2210 ** 2211 ** ^The sqlite3_malloc() routine returns a pointer to a block 2212 ** of memory at least N bytes in length, where N is the parameter. 2213 ** ^If sqlite3_malloc() is unable to obtain sufficient free 2214 ** memory, it returns a NULL pointer. ^If the parameter N to 2215 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2216 ** a NULL pointer. 2217 ** 2218 ** ^Calling sqlite3_free() with a pointer previously returned 2219 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2220 ** that it might be reused. ^The sqlite3_free() routine is 2221 ** a no-op if is called with a NULL pointer. Passing a NULL pointer 2222 ** to sqlite3_free() is harmless. After being freed, memory 2223 ** should neither be read nor written. Even reading previously freed 2224 ** memory might result in a segmentation fault or other severe error. 2225 ** Memory corruption, a segmentation fault, or other severe error 2226 ** might result if sqlite3_free() is called with a non-NULL pointer that 2227 ** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2228 ** 2229 ** ^(The sqlite3_realloc() interface attempts to resize a 2230 ** prior memory allocation to be at least N bytes, where N is the 2231 ** second parameter. The memory allocation to be resized is the first 2232 ** parameter.)^ ^ If the first parameter to sqlite3_realloc() 2233 ** is a NULL pointer then its behavior is identical to calling 2234 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 2235 ** ^If the second parameter to sqlite3_realloc() is zero or 2236 ** negative then the behavior is exactly the same as calling 2237 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 2238 ** ^sqlite3_realloc() returns a pointer to a memory allocation 2239 ** of at least N bytes in size or NULL if sufficient memory is unavailable. 2240 ** ^If M is the size of the prior allocation, then min(N,M) bytes 2241 ** of the prior allocation are copied into the beginning of buffer returned 2242 ** by sqlite3_realloc() and the prior allocation is freed. 2243 ** ^If sqlite3_realloc() returns NULL, then the prior allocation 2244 ** is not freed. 2245 ** 2246 ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 2247 ** is always aligned to at least an 8 byte boundary, or to a 2248 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2249 ** option is used. 2250 ** 2251 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2252 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2253 ** implementation of these routines to be omitted. That capability 2254 ** is no longer provided. Only built-in memory allocators can be used. 2255 ** 2256 ** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2257 ** the system malloc() and free() directly when converting 2258 ** filenames between the UTF-8 encoding used by SQLite 2259 ** and whatever filename encoding is used by the particular Windows 2260 ** installation. Memory allocation errors were detected, but 2261 ** they were reported back as [SQLITE_CANTOPEN] or 2262 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2263 ** 2264 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2265 ** must be either NULL or else pointers obtained from a prior 2266 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2267 ** not yet been released. 2268 ** 2269 ** The application must not read or write any part of 2270 ** a block of memory after it has been released using 2271 ** [sqlite3_free()] or [sqlite3_realloc()]. 2272 */ 2273 SQLITE_API void *sqlite3_malloc(int); 2274 SQLITE_API void *sqlite3_realloc(void*, int); 2275 SQLITE_API void sqlite3_free(void*); 2276 2277 /* 2278 ** CAPI3REF: Memory Allocator Statistics 2279 ** 2280 ** SQLite provides these two interfaces for reporting on the status 2281 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2282 ** routines, which form the built-in memory allocation subsystem. 2283 ** 2284 ** ^The [sqlite3_memory_used()] routine returns the number of bytes 2285 ** of memory currently outstanding (malloced but not freed). 2286 ** ^The [sqlite3_memory_highwater()] routine returns the maximum 2287 ** value of [sqlite3_memory_used()] since the high-water mark 2288 ** was last reset. ^The values returned by [sqlite3_memory_used()] and 2289 ** [sqlite3_memory_highwater()] include any overhead 2290 ** added by SQLite in its implementation of [sqlite3_malloc()], 2291 ** but not overhead added by the any underlying system library 2292 ** routines that [sqlite3_malloc()] may call. 2293 ** 2294 ** ^The memory high-water mark is reset to the current value of 2295 ** [sqlite3_memory_used()] if and only if the parameter to 2296 ** [sqlite3_memory_highwater()] is true. ^The value returned 2297 ** by [sqlite3_memory_highwater(1)] is the high-water mark 2298 ** prior to the reset. 2299 */ 2300 SQLITE_API sqlite3_int64 sqlite3_memory_used(void); 2301 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2302 2303 /* 2304 ** CAPI3REF: Pseudo-Random Number Generator 2305 ** 2306 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2307 ** select random [ROWID | ROWIDs] when inserting new records into a table that 2308 ** already uses the largest possible [ROWID]. The PRNG is also used for 2309 ** the build-in random() and randomblob() SQL functions. This interface allows 2310 ** applications to access the same PRNG for other purposes. 2311 ** 2312 ** ^A call to this routine stores N bytes of randomness into buffer P. 2313 ** 2314 ** ^The first time this routine is invoked (either internally or by 2315 ** the application) the PRNG is seeded using randomness obtained 2316 ** from the xRandomness method of the default [sqlite3_vfs] object. 2317 ** ^On all subsequent invocations, the pseudo-randomness is generated 2318 ** internally and without recourse to the [sqlite3_vfs] xRandomness 2319 ** method. 2320 */ 2321 SQLITE_API void sqlite3_randomness(int N, void *P); 2322 2323 /* 2324 ** CAPI3REF: Compile-Time Authorization Callbacks 2325 ** 2326 ** ^This routine registers an authorizer callback with a particular 2327 ** [database connection], supplied in the first argument. 2328 ** ^The authorizer callback is invoked as SQL statements are being compiled 2329 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2330 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2331 ** points during the compilation process, as logic is being created 2332 ** to perform various actions, the authorizer callback is invoked to 2333 ** see if those actions are allowed. ^The authorizer callback should 2334 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2335 ** specific action but allow the SQL statement to continue to be 2336 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2337 ** rejected with an error. ^If the authorizer callback returns 2338 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2339 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2340 ** the authorizer will fail with an error message. 2341 ** 2342 ** When the callback returns [SQLITE_OK], that means the operation 2343 ** requested is ok. ^When the callback returns [SQLITE_DENY], the 2344 ** [sqlite3_prepare_v2()] or equivalent call that triggered the 2345 ** authorizer will fail with an error message explaining that 2346 ** access is denied. 2347 ** 2348 ** ^The first parameter to the authorizer callback is a copy of the third 2349 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2350 ** to the callback is an integer [SQLITE_COPY | action code] that specifies 2351 ** the particular action to be authorized. ^The third through sixth parameters 2352 ** to the callback are zero-terminated strings that contain additional 2353 ** details about the action to be authorized. 2354 ** 2355 ** ^If the action code is [SQLITE_READ] 2356 ** and the callback returns [SQLITE_IGNORE] then the 2357 ** [prepared statement] statement is constructed to substitute 2358 ** a NULL value in place of the table column that would have 2359 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2360 ** return can be used to deny an untrusted user access to individual 2361 ** columns of a table. 2362 ** ^If the action code is [SQLITE_DELETE] and the callback returns 2363 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2364 ** [truncate optimization] is disabled and all rows are deleted individually. 2365 ** 2366 ** An authorizer is used when [sqlite3_prepare | preparing] 2367 ** SQL statements from an untrusted source, to ensure that the SQL statements 2368 ** do not try to access data they are not allowed to see, or that they do not 2369 ** try to execute malicious statements that damage the database. For 2370 ** example, an application may allow a user to enter arbitrary 2371 ** SQL queries for evaluation by a database. But the application does 2372 ** not want the user to be able to make arbitrary changes to the 2373 ** database. An authorizer could then be put in place while the 2374 ** user-entered SQL is being [sqlite3_prepare | prepared] that 2375 ** disallows everything except [SELECT] statements. 2376 ** 2377 ** Applications that need to process SQL from untrusted sources 2378 ** might also consider lowering resource limits using [sqlite3_limit()] 2379 ** and limiting database size using the [max_page_count] [PRAGMA] 2380 ** in addition to using an authorizer. 2381 ** 2382 ** ^(Only a single authorizer can be in place on a database connection 2383 ** at a time. Each call to sqlite3_set_authorizer overrides the 2384 ** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2385 ** The authorizer is disabled by default. 2386 ** 2387 ** The authorizer callback must not do anything that will modify 2388 ** the database connection that invoked the authorizer callback. 2389 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2390 ** database connections for the meaning of "modify" in this paragraph. 2391 ** 2392 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2393 ** statement might be re-prepared during [sqlite3_step()] due to a 2394 ** schema change. Hence, the application should ensure that the 2395 ** correct authorizer callback remains in place during the [sqlite3_step()]. 2396 ** 2397 ** ^Note that the authorizer callback is invoked only during 2398 ** [sqlite3_prepare()] or its variants. Authorization is not 2399 ** performed during statement evaluation in [sqlite3_step()], unless 2400 ** as stated in the previous paragraph, sqlite3_step() invokes 2401 ** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2402 */ 2403 SQLITE_API int sqlite3_set_authorizer( 2404 sqlite3*, 2405 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2406 void *pUserData 2407 ); 2408 2409 /* 2410 ** CAPI3REF: Authorizer Return Codes 2411 ** 2412 ** The [sqlite3_set_authorizer | authorizer callback function] must 2413 ** return either [SQLITE_OK] or one of these two constants in order 2414 ** to signal SQLite whether or not the action is permitted. See the 2415 ** [sqlite3_set_authorizer | authorizer documentation] for additional 2416 ** information. 2417 ** 2418 ** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code] 2419 ** from the [sqlite3_vtab_on_conflict()] interface. 2420 */ 2421 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2422 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2423 2424 /* 2425 ** CAPI3REF: Authorizer Action Codes 2426 ** 2427 ** The [sqlite3_set_authorizer()] interface registers a callback function 2428 ** that is invoked to authorize certain SQL statement actions. The 2429 ** second parameter to the callback is an integer code that specifies 2430 ** what action is being authorized. These are the integer action codes that 2431 ** the authorizer callback may be passed. 2432 ** 2433 ** These action code values signify what kind of operation is to be 2434 ** authorized. The 3rd and 4th parameters to the authorization 2435 ** callback function will be parameters or NULL depending on which of these 2436 ** codes is used as the second parameter. ^(The 5th parameter to the 2437 ** authorizer callback is the name of the database ("main", "temp", 2438 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2439 ** is the name of the inner-most trigger or view that is responsible for 2440 ** the access attempt or NULL if this access attempt is directly from 2441 ** top-level SQL code. 2442 */ 2443 /******************************************* 3rd ************ 4th ***********/ 2444 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2445 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2446 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2447 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2448 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2449 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2450 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2451 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2452 #define SQLITE_DELETE 9 /* Table Name NULL */ 2453 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2454 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2455 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2456 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2457 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2458 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2459 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2460 #define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2461 #define SQLITE_INSERT 18 /* Table Name NULL */ 2462 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2463 #define SQLITE_READ 20 /* Table Name Column Name */ 2464 #define SQLITE_SELECT 21 /* NULL NULL */ 2465 #define SQLITE_TRANSACTION 22 /* Operation NULL */ 2466 #define SQLITE_UPDATE 23 /* Table Name Column Name */ 2467 #define SQLITE_ATTACH 24 /* Filename NULL */ 2468 #define SQLITE_DETACH 25 /* Database Name NULL */ 2469 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2470 #define SQLITE_REINDEX 27 /* Index Name NULL */ 2471 #define SQLITE_ANALYZE 28 /* Table Name NULL */ 2472 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2473 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2474 #define SQLITE_FUNCTION 31 /* NULL Function Name */ 2475 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2476 #define SQLITE_COPY 0 /* No longer used */ 2477 2478 /* 2479 ** CAPI3REF: Tracing And Profiling Functions 2480 ** 2481 ** These routines register callback functions that can be used for 2482 ** tracing and profiling the execution of SQL statements. 2483 ** 2484 ** ^The callback function registered by sqlite3_trace() is invoked at 2485 ** various times when an SQL statement is being run by [sqlite3_step()]. 2486 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2487 ** SQL statement text as the statement first begins executing. 2488 ** ^(Additional sqlite3_trace() callbacks might occur 2489 ** as each triggered subprogram is entered. The callbacks for triggers 2490 ** contain a UTF-8 SQL comment that identifies the trigger.)^ 2491 ** 2492 ** ^The callback function registered by sqlite3_profile() is invoked 2493 ** as each SQL statement finishes. ^The profile callback contains 2494 ** the original statement text and an estimate of wall-clock time 2495 ** of how long that statement took to run. ^The profile callback 2496 ** time is in units of nanoseconds, however the current implementation 2497 ** is only capable of millisecond resolution so the six least significant 2498 ** digits in the time are meaningless. Future versions of SQLite 2499 ** might provide greater resolution on the profiler callback. The 2500 ** sqlite3_profile() function is considered experimental and is 2501 ** subject to change in future versions of SQLite. 2502 */ 2503 SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2504 SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2505 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2506 2507 /* 2508 ** CAPI3REF: Query Progress Callbacks 2509 ** 2510 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2511 ** function X to be invoked periodically during long running calls to 2512 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2513 ** database connection D. An example use for this 2514 ** interface is to keep a GUI updated during a large query. 2515 ** 2516 ** ^The parameter P is passed through as the only parameter to the 2517 ** callback function X. ^The parameter N is the number of 2518 ** [virtual machine instructions] that are evaluated between successive 2519 ** invocations of the callback X. 2520 ** 2521 ** ^Only a single progress handler may be defined at one time per 2522 ** [database connection]; setting a new progress handler cancels the 2523 ** old one. ^Setting parameter X to NULL disables the progress handler. 2524 ** ^The progress handler is also disabled by setting N to a value less 2525 ** than 1. 2526 ** 2527 ** ^If the progress callback returns non-zero, the operation is 2528 ** interrupted. This feature can be used to implement a 2529 ** "Cancel" button on a GUI progress dialog box. 2530 ** 2531 ** The progress handler callback must not do anything that will modify 2532 ** the database connection that invoked the progress handler. 2533 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2534 ** database connections for the meaning of "modify" in this paragraph. 2535 ** 2536 */ 2537 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2538 2539 /* 2540 ** CAPI3REF: Opening A New Database Connection 2541 ** 2542 ** ^These routines open an SQLite database file as specified by the 2543 ** filename argument. ^The filename argument is interpreted as UTF-8 for 2544 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2545 ** order for sqlite3_open16(). ^(A [database connection] handle is usually 2546 ** returned in *ppDb, even if an error occurs. The only exception is that 2547 ** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2548 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2549 ** object.)^ ^(If the database is opened (and/or created) successfully, then 2550 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2551 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2552 ** an English language description of the error following a failure of any 2553 ** of the sqlite3_open() routines. 2554 ** 2555 ** ^The default encoding for the database will be UTF-8 if 2556 ** sqlite3_open() or sqlite3_open_v2() is called and 2557 ** UTF-16 in the native byte order if sqlite3_open16() is used. 2558 ** 2559 ** Whether or not an error occurs when it is opened, resources 2560 ** associated with the [database connection] handle should be released by 2561 ** passing it to [sqlite3_close()] when it is no longer required. 2562 ** 2563 ** The sqlite3_open_v2() interface works like sqlite3_open() 2564 ** except that it accepts two additional parameters for additional control 2565 ** over the new database connection. ^(The flags parameter to 2566 ** sqlite3_open_v2() can take one of 2567 ** the following three values, optionally combined with the 2568 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2569 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2570 ** 2571 ** <dl> 2572 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2573 ** <dd>The database is opened in read-only mode. If the database does not 2574 ** already exist, an error is returned.</dd>)^ 2575 ** 2576 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2577 ** <dd>The database is opened for reading and writing if possible, or reading 2578 ** only if the file is write protected by the operating system. In either 2579 ** case the database must already exist, otherwise an error is returned.</dd>)^ 2580 ** 2581 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2582 ** <dd>The database is opened for reading and writing, and is created if 2583 ** it does not already exist. This is the behavior that is always used for 2584 ** sqlite3_open() and sqlite3_open16().</dd>)^ 2585 ** </dl> 2586 ** 2587 ** If the 3rd parameter to sqlite3_open_v2() is not one of the 2588 ** combinations shown above optionally combined with other 2589 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2590 ** then the behavior is undefined. 2591 ** 2592 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2593 ** opens in the multi-thread [threading mode] as long as the single-thread 2594 ** mode has not been set at compile-time or start-time. ^If the 2595 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2596 ** in the serialized [threading mode] unless single-thread was 2597 ** previously selected at compile-time or start-time. 2598 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2599 ** eligible to use [shared cache mode], regardless of whether or not shared 2600 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2601 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2602 ** participate in [shared cache mode] even if it is enabled. 2603 ** 2604 ** ^The fourth parameter to sqlite3_open_v2() is the name of the 2605 ** [sqlite3_vfs] object that defines the operating system interface that 2606 ** the new database connection should use. ^If the fourth parameter is 2607 ** a NULL pointer then the default [sqlite3_vfs] object is used. 2608 ** 2609 ** ^If the filename is ":memory:", then a private, temporary in-memory database 2610 ** is created for the connection. ^This in-memory database will vanish when 2611 ** the database connection is closed. Future versions of SQLite might 2612 ** make use of additional special filenames that begin with the ":" character. 2613 ** It is recommended that when a database filename actually does begin with 2614 ** a ":" character you should prefix the filename with a pathname such as 2615 ** "./" to avoid ambiguity. 2616 ** 2617 ** ^If the filename is an empty string, then a private, temporary 2618 ** on-disk database will be created. ^This private database will be 2619 ** automatically deleted as soon as the database connection is closed. 2620 ** 2621 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2622 ** 2623 ** ^If [URI filename] interpretation is enabled, and the filename argument 2624 ** begins with "file:", then the filename is interpreted as a URI. ^URI 2625 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2626 ** set in the fourth argument to sqlite3_open_v2(), or if it has 2627 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2628 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2629 ** As of SQLite version 3.7.7, URI filename interpretation is turned off 2630 ** by default, but future releases of SQLite might enable URI filename 2631 ** interpretation by default. See "[URI filenames]" for additional 2632 ** information. 2633 ** 2634 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2635 ** authority, then it must be either an empty string or the string 2636 ** "localhost". ^If the authority is not an empty string or "localhost", an 2637 ** error is returned to the caller. ^The fragment component of a URI, if 2638 ** present, is ignored. 2639 ** 2640 ** ^SQLite uses the path component of the URI as the name of the disk file 2641 ** which contains the database. ^If the path begins with a '/' character, 2642 ** then it is interpreted as an absolute path. ^If the path does not begin 2643 ** with a '/' (meaning that the authority section is omitted from the URI) 2644 ** then the path is interpreted as a relative path. 2645 ** ^On windows, the first component of an absolute path 2646 ** is a drive specification (e.g. "C:"). 2647 ** 2648 ** [[core URI query parameters]] 2649 ** The query component of a URI may contain parameters that are interpreted 2650 ** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2651 ** SQLite interprets the following three query parameters: 2652 ** 2653 ** <ul> 2654 ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2655 ** a VFS object that provides the operating system interface that should 2656 ** be used to access the database file on disk. ^If this option is set to 2657 ** an empty string the default VFS object is used. ^Specifying an unknown 2658 ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2659 ** present, then the VFS specified by the option takes precedence over 2660 ** the value passed as the fourth parameter to sqlite3_open_v2(). 2661 ** 2662 ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 2663 ** "rwc", or "memory". Attempting to set it to any other value is 2664 ** an error)^. 2665 ** ^If "ro" is specified, then the database is opened for read-only 2666 ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2667 ** third argument to sqlite3_open_v2(). ^If the mode option is set to 2668 ** "rw", then the database is opened for read-write (but not create) 2669 ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2670 ** been set. ^Value "rwc" is equivalent to setting both 2671 ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 2672 ** set to "memory" then a pure [in-memory database] that never reads 2673 ** or writes from disk is used. ^It is an error to specify a value for 2674 ** the mode parameter that is less restrictive than that specified by 2675 ** the flags passed in the third parameter to sqlite3_open_v2(). 2676 ** 2677 ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2678 ** "private". ^Setting it to "shared" is equivalent to setting the 2679 ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2680 ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2681 ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2682 ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2683 ** a URI filename, its value overrides any behavior requested by setting 2684 ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2685 ** </ul> 2686 ** 2687 ** ^Specifying an unknown parameter in the query component of a URI is not an 2688 ** error. Future versions of SQLite might understand additional query 2689 ** parameters. See "[query parameters with special meaning to SQLite]" for 2690 ** additional information. 2691 ** 2692 ** [[URI filename examples]] <h3>URI filename examples</h3> 2693 ** 2694 ** <table border="1" align=center cellpadding=5> 2695 ** <tr><th> URI filenames <th> Results 2696 ** <tr><td> file:data.db <td> 2697 ** Open the file "data.db" in the current directory. 2698 ** <tr><td> file:/home/fred/data.db<br> 2699 ** file:///home/fred/data.db <br> 2700 ** file://localhost/home/fred/data.db <br> <td> 2701 ** Open the database file "/home/fred/data.db". 2702 ** <tr><td> file://darkstar/home/fred/data.db <td> 2703 ** An error. "darkstar" is not a recognized authority. 2704 ** <tr><td style="white-space:nowrap"> 2705 ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2706 ** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2707 ** C:. Note that the %20 escaping in this example is not strictly 2708 ** necessary - space characters can be used literally 2709 ** in URI filenames. 2710 ** <tr><td> file:data.db?mode=ro&cache=private <td> 2711 ** Open file "data.db" in the current directory for read-only access. 2712 ** Regardless of whether or not shared-cache mode is enabled by 2713 ** default, use a private cache. 2714 ** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td> 2715 ** Open file "/home/fred/data.db". Use the special VFS "unix-nolock". 2716 ** <tr><td> file:data.db?mode=readonly <td> 2717 ** An error. "readonly" is not a valid option for the "mode" parameter. 2718 ** </table> 2719 ** 2720 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2721 ** query components of a URI. A hexadecimal escape sequence consists of a 2722 ** percent sign - "%" - followed by exactly two hexadecimal digits 2723 ** specifying an octet value. ^Before the path or query components of a 2724 ** URI filename are interpreted, they are encoded using UTF-8 and all 2725 ** hexadecimal escape sequences replaced by a single byte containing the 2726 ** corresponding octet. If this process generates an invalid UTF-8 encoding, 2727 ** the results are undefined. 2728 ** 2729 ** <b>Note to Windows users:</b> The encoding used for the filename argument 2730 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2731 ** codepage is currently defined. Filenames containing international 2732 ** characters must be converted to UTF-8 prior to passing them into 2733 ** sqlite3_open() or sqlite3_open_v2(). 2734 ** 2735 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set 2736 ** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 2737 ** features that require the use of temporary files may fail. 2738 ** 2739 ** See also: [sqlite3_temp_directory] 2740 */ 2741 SQLITE_API int sqlite3_open( 2742 const char *filename, /* Database filename (UTF-8) */ 2743 sqlite3 **ppDb /* OUT: SQLite db handle */ 2744 ); 2745 SQLITE_API int sqlite3_open16( 2746 const void *filename, /* Database filename (UTF-16) */ 2747 sqlite3 **ppDb /* OUT: SQLite db handle */ 2748 ); 2749 SQLITE_API int sqlite3_open_v2( 2750 const char *filename, /* Database filename (UTF-8) */ 2751 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2752 int flags, /* Flags */ 2753 const char *zVfs /* Name of VFS module to use */ 2754 ); 2755 2756 /* 2757 ** CAPI3REF: Obtain Values For URI Parameters 2758 ** 2759 ** These are utility routines, useful to VFS implementations, that check 2760 ** to see if a database file was a URI that contained a specific query 2761 ** parameter, and if so obtains the value of that query parameter. 2762 ** 2763 ** If F is the database filename pointer passed into the xOpen() method of 2764 ** a VFS implementation when the flags parameter to xOpen() has one or 2765 ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 2766 ** P is the name of the query parameter, then 2767 ** sqlite3_uri_parameter(F,P) returns the value of the P 2768 ** parameter if it exists or a NULL pointer if P does not appear as a 2769 ** query parameter on F. If P is a query parameter of F 2770 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns 2771 ** a pointer to an empty string. 2772 ** 2773 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 2774 ** parameter and returns true (1) or false (0) according to the value 2775 ** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 2776 ** value of query parameter P is one of "yes", "true", or "on" in any 2777 ** case or if the value begins with a non-zero number. The 2778 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 2779 ** query parameter P is one of "no", "false", or "off" in any case or 2780 ** if the value begins with a numeric zero. If P is not a query 2781 ** parameter on F or if the value of P is does not match any of the 2782 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 2783 ** 2784 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 2785 ** 64-bit signed integer and returns that integer, or D if P does not 2786 ** exist. If the value of P is something other than an integer, then 2787 ** zero is returned. 2788 ** 2789 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 2790 ** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 2791 ** is not a database file pathname pointer that SQLite passed into the xOpen 2792 ** VFS method, then the behavior of this routine is undefined and probably 2793 ** undesirable. 2794 */ 2795 SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 2796 SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 2797 SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 2798 2799 2800 /* 2801 ** CAPI3REF: Error Codes And Messages 2802 ** 2803 ** ^The sqlite3_errcode() interface returns the numeric [result code] or 2804 ** [extended result code] for the most recent failed sqlite3_* API call 2805 ** associated with a [database connection]. If a prior API call failed 2806 ** but the most recent API call succeeded, the return value from 2807 ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2808 ** interface is the same except that it always returns the 2809 ** [extended result code] even when extended result codes are 2810 ** disabled. 2811 ** 2812 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2813 ** text that describes the error, as either UTF-8 or UTF-16 respectively. 2814 ** ^(Memory to hold the error message string is managed internally. 2815 ** The application does not need to worry about freeing the result. 2816 ** However, the error string might be overwritten or deallocated by 2817 ** subsequent calls to other SQLite interface functions.)^ 2818 ** 2819 ** ^The sqlite3_errstr() interface returns the English-language text 2820 ** that describes the [result code], as UTF-8. 2821 ** ^(Memory to hold the error message string is managed internally 2822 ** and must not be freed by the application)^. 2823 ** 2824 ** When the serialized [threading mode] is in use, it might be the 2825 ** case that a second error occurs on a separate thread in between 2826 ** the time of the first error and the call to these interfaces. 2827 ** When that happens, the second error will be reported since these 2828 ** interfaces always report the most recent result. To avoid 2829 ** this, each thread can obtain exclusive use of the [database connection] D 2830 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2831 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2832 ** all calls to the interfaces listed here are completed. 2833 ** 2834 ** If an interface fails with SQLITE_MISUSE, that means the interface 2835 ** was invoked incorrectly by the application. In that case, the 2836 ** error code and message may or may not be set. 2837 */ 2838 SQLITE_API int sqlite3_errcode(sqlite3 *db); 2839 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db); 2840 SQLITE_API const char *sqlite3_errmsg(sqlite3*); 2841 SQLITE_API const void *sqlite3_errmsg16(sqlite3*); 2842 SQLITE_API const char *sqlite3_errstr(int); 2843 2844 /* 2845 ** CAPI3REF: SQL Statement Object 2846 ** KEYWORDS: {prepared statement} {prepared statements} 2847 ** 2848 ** An instance of this object represents a single SQL statement. 2849 ** This object is variously known as a "prepared statement" or a 2850 ** "compiled SQL statement" or simply as a "statement". 2851 ** 2852 ** The life of a statement object goes something like this: 2853 ** 2854 ** <ol> 2855 ** <li> Create the object using [sqlite3_prepare_v2()] or a related 2856 ** function. 2857 ** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2858 ** interfaces. 2859 ** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2860 ** <li> Reset the statement using [sqlite3_reset()] then go back 2861 ** to step 2. Do this zero or more times. 2862 ** <li> Destroy the object using [sqlite3_finalize()]. 2863 ** </ol> 2864 ** 2865 ** Refer to documentation on individual methods above for additional 2866 ** information. 2867 */ 2868 typedef struct sqlite3_stmt sqlite3_stmt; 2869 2870 /* 2871 ** CAPI3REF: Run-time Limits 2872 ** 2873 ** ^(This interface allows the size of various constructs to be limited 2874 ** on a connection by connection basis. The first parameter is the 2875 ** [database connection] whose limit is to be set or queried. The 2876 ** second parameter is one of the [limit categories] that define a 2877 ** class of constructs to be size limited. The third parameter is the 2878 ** new limit for that construct.)^ 2879 ** 2880 ** ^If the new limit is a negative number, the limit is unchanged. 2881 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 2882 ** [limits | hard upper bound] 2883 ** set at compile-time by a C preprocessor macro called 2884 ** [limits | SQLITE_MAX_<i>NAME</i>]. 2885 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2886 ** ^Attempts to increase a limit above its hard upper bound are 2887 ** silently truncated to the hard upper bound. 2888 ** 2889 ** ^Regardless of whether or not the limit was changed, the 2890 ** [sqlite3_limit()] interface returns the prior value of the limit. 2891 ** ^Hence, to find the current value of a limit without changing it, 2892 ** simply invoke this interface with the third parameter set to -1. 2893 ** 2894 ** Run-time limits are intended for use in applications that manage 2895 ** both their own internal database and also databases that are controlled 2896 ** by untrusted external sources. An example application might be a 2897 ** web browser that has its own databases for storing history and 2898 ** separate databases controlled by JavaScript applications downloaded 2899 ** off the Internet. The internal databases can be given the 2900 ** large, default limits. Databases managed by external sources can 2901 ** be given much smaller limits designed to prevent a denial of service 2902 ** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2903 ** interface to further control untrusted SQL. The size of the database 2904 ** created by an untrusted script can be contained using the 2905 ** [max_page_count] [PRAGMA]. 2906 ** 2907 ** New run-time limit categories may be added in future releases. 2908 */ 2909 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal); 2910 2911 /* 2912 ** CAPI3REF: Run-Time Limit Categories 2913 ** KEYWORDS: {limit category} {*limit categories} 2914 ** 2915 ** These constants define various performance limits 2916 ** that can be lowered at run-time using [sqlite3_limit()]. 2917 ** The synopsis of the meanings of the various limits is shown below. 2918 ** Additional information is available at [limits | Limits in SQLite]. 2919 ** 2920 ** <dl> 2921 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2922 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 2923 ** 2924 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2925 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2926 ** 2927 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2928 ** <dd>The maximum number of columns in a table definition or in the 2929 ** result set of a [SELECT] or the maximum number of columns in an index 2930 ** or in an ORDER BY or GROUP BY clause.</dd>)^ 2931 ** 2932 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2933 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2934 ** 2935 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2936 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2937 ** 2938 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2939 ** <dd>The maximum number of instructions in a virtual machine program 2940 ** used to implement an SQL statement. This limit is not currently 2941 ** enforced, though that might be added in some future release of 2942 ** SQLite.</dd>)^ 2943 ** 2944 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2945 ** <dd>The maximum number of arguments on a function.</dd>)^ 2946 ** 2947 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2948 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2949 ** 2950 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 2951 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2952 ** <dd>The maximum length of the pattern argument to the [LIKE] or 2953 ** [GLOB] operators.</dd>)^ 2954 ** 2955 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 2956 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2957 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 2958 ** 2959 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2960 ** <dd>The maximum depth of recursion for triggers.</dd>)^ 2961 ** </dl> 2962 */ 2963 #define SQLITE_LIMIT_LENGTH 0 2964 #define SQLITE_LIMIT_SQL_LENGTH 1 2965 #define SQLITE_LIMIT_COLUMN 2 2966 #define SQLITE_LIMIT_EXPR_DEPTH 3 2967 #define SQLITE_LIMIT_COMPOUND_SELECT 4 2968 #define SQLITE_LIMIT_VDBE_OP 5 2969 #define SQLITE_LIMIT_FUNCTION_ARG 6 2970 #define SQLITE_LIMIT_ATTACHED 7 2971 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2972 #define SQLITE_LIMIT_VARIABLE_NUMBER 9 2973 #define SQLITE_LIMIT_TRIGGER_DEPTH 10 2974 2975 /* 2976 ** CAPI3REF: Compiling An SQL Statement 2977 ** KEYWORDS: {SQL statement compiler} 2978 ** 2979 ** To execute an SQL query, it must first be compiled into a byte-code 2980 ** program using one of these routines. 2981 ** 2982 ** The first argument, "db", is a [database connection] obtained from a 2983 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2984 ** [sqlite3_open16()]. The database connection must not have been closed. 2985 ** 2986 ** The second argument, "zSql", is the statement to be compiled, encoded 2987 ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2988 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2989 ** use UTF-16. 2990 ** 2991 ** ^If the nByte argument is less than zero, then zSql is read up to the 2992 ** first zero terminator. ^If nByte is non-negative, then it is the maximum 2993 ** number of bytes read from zSql. ^When nByte is non-negative, the 2994 ** zSql string ends at either the first '\000' or '\u0000' character or 2995 ** the nByte-th byte, whichever comes first. If the caller knows 2996 ** that the supplied string is nul-terminated, then there is a small 2997 ** performance advantage to be gained by passing an nByte parameter that 2998 ** is equal to the number of bytes in the input string <i>including</i> 2999 ** the nul-terminator bytes as this saves SQLite from having to 3000 ** make a copy of the input string. 3001 ** 3002 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3003 ** past the end of the first SQL statement in zSql. These routines only 3004 ** compile the first statement in zSql, so *pzTail is left pointing to 3005 ** what remains uncompiled. 3006 ** 3007 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3008 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3009 ** to NULL. ^If the input text contains no SQL (if the input is an empty 3010 ** string or a comment) then *ppStmt is set to NULL. 3011 ** The calling procedure is responsible for deleting the compiled 3012 ** SQL statement using [sqlite3_finalize()] after it has finished with it. 3013 ** ppStmt may not be NULL. 3014 ** 3015 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3016 ** otherwise an [error code] is returned. 3017 ** 3018 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 3019 ** recommended for all new programs. The two older interfaces are retained 3020 ** for backwards compatibility, but their use is discouraged. 3021 ** ^In the "v2" interfaces, the prepared statement 3022 ** that is returned (the [sqlite3_stmt] object) contains a copy of the 3023 ** original SQL text. This causes the [sqlite3_step()] interface to 3024 ** behave differently in three ways: 3025 ** 3026 ** <ol> 3027 ** <li> 3028 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3029 ** always used to do, [sqlite3_step()] will automatically recompile the SQL 3030 ** statement and try to run it again. 3031 ** </li> 3032 ** 3033 ** <li> 3034 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3035 ** [error codes] or [extended error codes]. ^The legacy behavior was that 3036 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3037 ** and the application would have to make a second call to [sqlite3_reset()] 3038 ** in order to find the underlying cause of the problem. With the "v2" prepare 3039 ** interfaces, the underlying reason for the error is returned immediately. 3040 ** </li> 3041 ** 3042 ** <li> 3043 ** ^If the specific value bound to [parameter | host parameter] in the 3044 ** WHERE clause might influence the choice of query plan for a statement, 3045 ** then the statement will be automatically recompiled, as if there had been 3046 ** a schema change, on the first [sqlite3_step()] call following any change 3047 ** to the [sqlite3_bind_text | bindings] of that [parameter]. 3048 ** ^The specific value of WHERE-clause [parameter] might influence the 3049 ** choice of query plan if the parameter is the left-hand side of a [LIKE] 3050 ** or [GLOB] operator or if the parameter is compared to an indexed column 3051 ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3052 ** the 3053 ** </li> 3054 ** </ol> 3055 */ 3056 SQLITE_API int sqlite3_prepare( 3057 sqlite3 *db, /* Database handle */ 3058 const char *zSql, /* SQL statement, UTF-8 encoded */ 3059 int nByte, /* Maximum length of zSql in bytes. */ 3060 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3061 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3062 ); 3063 SQLITE_API int sqlite3_prepare_v2( 3064 sqlite3 *db, /* Database handle */ 3065 const char *zSql, /* SQL statement, UTF-8 encoded */ 3066 int nByte, /* Maximum length of zSql in bytes. */ 3067 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3068 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3069 ); 3070 SQLITE_API int sqlite3_prepare16( 3071 sqlite3 *db, /* Database handle */ 3072 const void *zSql, /* SQL statement, UTF-16 encoded */ 3073 int nByte, /* Maximum length of zSql in bytes. */ 3074 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3075 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3076 ); 3077 SQLITE_API int sqlite3_prepare16_v2( 3078 sqlite3 *db, /* Database handle */ 3079 const void *zSql, /* SQL statement, UTF-16 encoded */ 3080 int nByte, /* Maximum length of zSql in bytes. */ 3081 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3082 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3083 ); 3084 3085 /* 3086 ** CAPI3REF: Retrieving Statement SQL 3087 ** 3088 ** ^This interface can be used to retrieve a saved copy of the original 3089 ** SQL text used to create a [prepared statement] if that statement was 3090 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 3091 */ 3092 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt); 3093 3094 /* 3095 ** CAPI3REF: Determine If An SQL Statement Writes The Database 3096 ** 3097 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3098 ** and only if the [prepared statement] X makes no direct changes to 3099 ** the content of the database file. 3100 ** 3101 ** Note that [application-defined SQL functions] or 3102 ** [virtual tables] might change the database indirectly as a side effect. 3103 ** ^(For example, if an application defines a function "eval()" that 3104 ** calls [sqlite3_exec()], then the following SQL statement would 3105 ** change the database file through side-effects: 3106 ** 3107 ** <blockquote><pre> 3108 ** SELECT eval('DELETE FROM t1') FROM t2; 3109 ** </pre></blockquote> 3110 ** 3111 ** But because the [SELECT] statement does not change the database file 3112 ** directly, sqlite3_stmt_readonly() would still return true.)^ 3113 ** 3114 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3115 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3116 ** since the statements themselves do not actually modify the database but 3117 ** rather they control the timing of when other statements modify the 3118 ** database. ^The [ATTACH] and [DETACH] statements also cause 3119 ** sqlite3_stmt_readonly() to return true since, while those statements 3120 ** change the configuration of a database connection, they do not make 3121 ** changes to the content of the database files on disk. 3122 */ 3123 SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3124 3125 /* 3126 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3127 ** 3128 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3129 ** [prepared statement] S has been stepped at least once using 3130 ** [sqlite3_step(S)] but has not run to completion and/or has not 3131 ** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3132 ** interface returns false if S is a NULL pointer. If S is not a 3133 ** NULL pointer and is not a pointer to a valid [prepared statement] 3134 ** object, then the behavior is undefined and probably undesirable. 3135 ** 3136 ** This interface can be used in combination [sqlite3_next_stmt()] 3137 ** to locate all prepared statements associated with a database 3138 ** connection that are in need of being reset. This can be used, 3139 ** for example, in diagnostic routines to search for prepared 3140 ** statements that are holding a transaction open. 3141 */ 3142 SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*); 3143 3144 /* 3145 ** CAPI3REF: Dynamically Typed Value Object 3146 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3147 ** 3148 ** SQLite uses the sqlite3_value object to represent all values 3149 ** that can be stored in a database table. SQLite uses dynamic typing 3150 ** for the values it stores. ^Values stored in sqlite3_value objects 3151 ** can be integers, floating point values, strings, BLOBs, or NULL. 3152 ** 3153 ** An sqlite3_value object may be either "protected" or "unprotected". 3154 ** Some interfaces require a protected sqlite3_value. Other interfaces 3155 ** will accept either a protected or an unprotected sqlite3_value. 3156 ** Every interface that accepts sqlite3_value arguments specifies 3157 ** whether or not it requires a protected sqlite3_value. 3158 ** 3159 ** The terms "protected" and "unprotected" refer to whether or not 3160 ** a mutex is held. An internal mutex is held for a protected 3161 ** sqlite3_value object but no mutex is held for an unprotected 3162 ** sqlite3_value object. If SQLite is compiled to be single-threaded 3163 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3164 ** or if SQLite is run in one of reduced mutex modes 3165 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3166 ** then there is no distinction between protected and unprotected 3167 ** sqlite3_value objects and they can be used interchangeably. However, 3168 ** for maximum code portability it is recommended that applications 3169 ** still make the distinction between protected and unprotected 3170 ** sqlite3_value objects even when not strictly required. 3171 ** 3172 ** ^The sqlite3_value objects that are passed as parameters into the 3173 ** implementation of [application-defined SQL functions] are protected. 3174 ** ^The sqlite3_value object returned by 3175 ** [sqlite3_column_value()] is unprotected. 3176 ** Unprotected sqlite3_value objects may only be used with 3177 ** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3178 ** The [sqlite3_value_blob | sqlite3_value_type()] family of 3179 ** interfaces require protected sqlite3_value objects. 3180 */ 3181 typedef struct Mem sqlite3_value; 3182 3183 /* 3184 ** CAPI3REF: SQL Function Context Object 3185 ** 3186 ** The context in which an SQL function executes is stored in an 3187 ** sqlite3_context object. ^A pointer to an sqlite3_context object 3188 ** is always first parameter to [application-defined SQL functions]. 3189 ** The application-defined SQL function implementation will pass this 3190 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3191 ** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3192 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3193 ** and/or [sqlite3_set_auxdata()]. 3194 */ 3195 typedef struct sqlite3_context sqlite3_context; 3196 3197 /* 3198 ** CAPI3REF: Binding Values To Prepared Statements 3199 ** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3200 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3201 ** 3202 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3203 ** literals may be replaced by a [parameter] that matches one of following 3204 ** templates: 3205 ** 3206 ** <ul> 3207 ** <li> ? 3208 ** <li> ?NNN 3209 ** <li> :VVV 3210 ** <li> @VVV 3211 ** <li> $VVV 3212 ** </ul> 3213 ** 3214 ** In the templates above, NNN represents an integer literal, 3215 ** and VVV represents an alphanumeric identifier.)^ ^The values of these 3216 ** parameters (also called "host parameter names" or "SQL parameters") 3217 ** can be set using the sqlite3_bind_*() routines defined here. 3218 ** 3219 ** ^The first argument to the sqlite3_bind_*() routines is always 3220 ** a pointer to the [sqlite3_stmt] object returned from 3221 ** [sqlite3_prepare_v2()] or its variants. 3222 ** 3223 ** ^The second argument is the index of the SQL parameter to be set. 3224 ** ^The leftmost SQL parameter has an index of 1. ^When the same named 3225 ** SQL parameter is used more than once, second and subsequent 3226 ** occurrences have the same index as the first occurrence. 3227 ** ^The index for named parameters can be looked up using the 3228 ** [sqlite3_bind_parameter_index()] API if desired. ^The index 3229 ** for "?NNN" parameters is the value of NNN. 3230 ** ^The NNN value must be between 1 and the [sqlite3_limit()] 3231 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3232 ** 3233 ** ^The third argument is the value to bind to the parameter. 3234 ** 3235 ** ^(In those routines that have a fourth argument, its value is the 3236 ** number of bytes in the parameter. To be clear: the value is the 3237 ** number of <u>bytes</u> in the value, not the number of characters.)^ 3238 ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3239 ** is negative, then the length of the string is 3240 ** the number of bytes up to the first zero terminator. 3241 ** If the fourth parameter to sqlite3_bind_blob() is negative, then 3242 ** the behavior is undefined. 3243 ** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3244 ** or sqlite3_bind_text16() then that parameter must be the byte offset 3245 ** where the NUL terminator would occur assuming the string were NUL 3246 ** terminated. If any NUL characters occur at byte offsets less than 3247 ** the value of the fourth parameter then the resulting string value will 3248 ** contain embedded NULs. The result of expressions involving strings 3249 ** with embedded NULs is undefined. 3250 ** 3251 ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 3252 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 3253 ** string after SQLite has finished with it. ^The destructor is called 3254 ** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(), 3255 ** sqlite3_bind_text(), or sqlite3_bind_text16() fails. 3256 ** ^If the fifth argument is 3257 ** the special value [SQLITE_STATIC], then SQLite assumes that the 3258 ** information is in static, unmanaged space and does not need to be freed. 3259 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3260 ** SQLite makes its own private copy of the data immediately, before 3261 ** the sqlite3_bind_*() routine returns. 3262 ** 3263 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3264 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3265 ** (just an integer to hold its size) while it is being processed. 3266 ** Zeroblobs are intended to serve as placeholders for BLOBs whose 3267 ** content is later written using 3268 ** [sqlite3_blob_open | incremental BLOB I/O] routines. 3269 ** ^A negative value for the zeroblob results in a zero-length BLOB. 3270 ** 3271 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3272 ** for the [prepared statement] or with a prepared statement for which 3273 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3274 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3275 ** routine is passed a [prepared statement] that has been finalized, the 3276 ** result is undefined and probably harmful. 3277 ** 3278 ** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3279 ** ^Unbound parameters are interpreted as NULL. 3280 ** 3281 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3282 ** [error code] if anything goes wrong. 3283 ** ^[SQLITE_RANGE] is returned if the parameter 3284 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3285 ** 3286 ** See also: [sqlite3_bind_parameter_count()], 3287 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3288 */ 3289 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3290 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double); 3291 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int); 3292 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3293 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int); 3294 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 3295 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3296 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3297 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3298 3299 /* 3300 ** CAPI3REF: Number Of SQL Parameters 3301 ** 3302 ** ^This routine can be used to find the number of [SQL parameters] 3303 ** in a [prepared statement]. SQL parameters are tokens of the 3304 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3305 ** placeholders for values that are [sqlite3_bind_blob | bound] 3306 ** to the parameters at a later time. 3307 ** 3308 ** ^(This routine actually returns the index of the largest (rightmost) 3309 ** parameter. For all forms except ?NNN, this will correspond to the 3310 ** number of unique parameters. If parameters of the ?NNN form are used, 3311 ** there may be gaps in the list.)^ 3312 ** 3313 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 3314 ** [sqlite3_bind_parameter_name()], and 3315 ** [sqlite3_bind_parameter_index()]. 3316 */ 3317 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*); 3318 3319 /* 3320 ** CAPI3REF: Name Of A Host Parameter 3321 ** 3322 ** ^The sqlite3_bind_parameter_name(P,N) interface returns 3323 ** the name of the N-th [SQL parameter] in the [prepared statement] P. 3324 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3325 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3326 ** respectively. 3327 ** In other words, the initial ":" or "$" or "@" or "?" 3328 ** is included as part of the name.)^ 3329 ** ^Parameters of the form "?" without a following integer have no name 3330 ** and are referred to as "nameless" or "anonymous parameters". 3331 ** 3332 ** ^The first host parameter has an index of 1, not 0. 3333 ** 3334 ** ^If the value N is out of range or if the N-th parameter is 3335 ** nameless, then NULL is returned. ^The returned string is 3336 ** always in UTF-8 encoding even if the named parameter was 3337 ** originally specified as UTF-16 in [sqlite3_prepare16()] or 3338 ** [sqlite3_prepare16_v2()]. 3339 ** 3340 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 3341 ** [sqlite3_bind_parameter_count()], and 3342 ** [sqlite3_bind_parameter_index()]. 3343 */ 3344 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3345 3346 /* 3347 ** CAPI3REF: Index Of A Parameter With A Given Name 3348 ** 3349 ** ^Return the index of an SQL parameter given its name. ^The 3350 ** index value returned is suitable for use as the second 3351 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3352 ** is returned if no matching parameter is found. ^The parameter 3353 ** name must be given in UTF-8 even if the original statement 3354 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3355 ** 3356 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 3357 ** [sqlite3_bind_parameter_count()], and 3358 ** [sqlite3_bind_parameter_index()]. 3359 */ 3360 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3361 3362 /* 3363 ** CAPI3REF: Reset All Bindings On A Prepared Statement 3364 ** 3365 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3366 ** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3367 ** ^Use this routine to reset all host parameters to NULL. 3368 */ 3369 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*); 3370 3371 /* 3372 ** CAPI3REF: Number Of Columns In A Result Set 3373 ** 3374 ** ^Return the number of columns in the result set returned by the 3375 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3376 ** statement that does not return data (for example an [UPDATE]). 3377 ** 3378 ** See also: [sqlite3_data_count()] 3379 */ 3380 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt); 3381 3382 /* 3383 ** CAPI3REF: Column Names In A Result Set 3384 ** 3385 ** ^These routines return the name assigned to a particular column 3386 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3387 ** interface returns a pointer to a zero-terminated UTF-8 string 3388 ** and sqlite3_column_name16() returns a pointer to a zero-terminated 3389 ** UTF-16 string. ^The first parameter is the [prepared statement] 3390 ** that implements the [SELECT] statement. ^The second parameter is the 3391 ** column number. ^The leftmost column is number 0. 3392 ** 3393 ** ^The returned string pointer is valid until either the [prepared statement] 3394 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3395 ** reprepared by the first call to [sqlite3_step()] for a particular run 3396 ** or until the next call to 3397 ** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3398 ** 3399 ** ^If sqlite3_malloc() fails during the processing of either routine 3400 ** (for example during a conversion from UTF-8 to UTF-16) then a 3401 ** NULL pointer is returned. 3402 ** 3403 ** ^The name of a result column is the value of the "AS" clause for 3404 ** that column, if there is an AS clause. If there is no AS clause 3405 ** then the name of the column is unspecified and may change from 3406 ** one release of SQLite to the next. 3407 */ 3408 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N); 3409 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3410 3411 /* 3412 ** CAPI3REF: Source Of Data In A Query Result 3413 ** 3414 ** ^These routines provide a means to determine the database, table, and 3415 ** table column that is the origin of a particular result column in 3416 ** [SELECT] statement. 3417 ** ^The name of the database or table or column can be returned as 3418 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3419 ** the database name, the _table_ routines return the table name, and 3420 ** the origin_ routines return the column name. 3421 ** ^The returned string is valid until the [prepared statement] is destroyed 3422 ** using [sqlite3_finalize()] or until the statement is automatically 3423 ** reprepared by the first call to [sqlite3_step()] for a particular run 3424 ** or until the same information is requested 3425 ** again in a different encoding. 3426 ** 3427 ** ^The names returned are the original un-aliased names of the 3428 ** database, table, and column. 3429 ** 3430 ** ^The first argument to these interfaces is a [prepared statement]. 3431 ** ^These functions return information about the Nth result column returned by 3432 ** the statement, where N is the second function argument. 3433 ** ^The left-most column is column 0 for these routines. 3434 ** 3435 ** ^If the Nth column returned by the statement is an expression or 3436 ** subquery and is not a column value, then all of these functions return 3437 ** NULL. ^These routine might also return NULL if a memory allocation error 3438 ** occurs. ^Otherwise, they return the name of the attached database, table, 3439 ** or column that query result column was extracted from. 3440 ** 3441 ** ^As with all other SQLite APIs, those whose names end with "16" return 3442 ** UTF-16 encoded strings and the other functions return UTF-8. 3443 ** 3444 ** ^These APIs are only available if the library was compiled with the 3445 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3446 ** 3447 ** If two or more threads call one or more of these routines against the same 3448 ** prepared statement and column at the same time then the results are 3449 ** undefined. 3450 ** 3451 ** If two or more threads call one or more 3452 ** [sqlite3_column_database_name | column metadata interfaces] 3453 ** for the same [prepared statement] and result column 3454 ** at the same time then the results are undefined. 3455 */ 3456 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3457 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3458 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3459 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3460 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3461 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3462 3463 /* 3464 ** CAPI3REF: Declared Datatype Of A Query Result 3465 ** 3466 ** ^(The first parameter is a [prepared statement]. 3467 ** If this statement is a [SELECT] statement and the Nth column of the 3468 ** returned result set of that [SELECT] is a table column (not an 3469 ** expression or subquery) then the declared type of the table 3470 ** column is returned.)^ ^If the Nth column of the result set is an 3471 ** expression or subquery, then a NULL pointer is returned. 3472 ** ^The returned string is always UTF-8 encoded. 3473 ** 3474 ** ^(For example, given the database schema: 3475 ** 3476 ** CREATE TABLE t1(c1 VARIANT); 3477 ** 3478 ** and the following statement to be compiled: 3479 ** 3480 ** SELECT c1 + 1, c1 FROM t1; 3481 ** 3482 ** this routine would return the string "VARIANT" for the second result 3483 ** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3484 ** 3485 ** ^SQLite uses dynamic run-time typing. ^So just because a column 3486 ** is declared to contain a particular type does not mean that the 3487 ** data stored in that column is of the declared type. SQLite is 3488 ** strongly typed, but the typing is dynamic not static. ^Type 3489 ** is associated with individual values, not with the containers 3490 ** used to hold those values. 3491 */ 3492 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3493 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3494 3495 /* 3496 ** CAPI3REF: Evaluate An SQL Statement 3497 ** 3498 ** After a [prepared statement] has been prepared using either 3499 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3500 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3501 ** must be called one or more times to evaluate the statement. 3502 ** 3503 ** The details of the behavior of the sqlite3_step() interface depend 3504 ** on whether the statement was prepared using the newer "v2" interface 3505 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3506 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3507 ** new "v2" interface is recommended for new applications but the legacy 3508 ** interface will continue to be supported. 3509 ** 3510 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3511 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3512 ** ^With the "v2" interface, any of the other [result codes] or 3513 ** [extended result codes] might be returned as well. 3514 ** 3515 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3516 ** database locks it needs to do its job. ^If the statement is a [COMMIT] 3517 ** or occurs outside of an explicit transaction, then you can retry the 3518 ** statement. If the statement is not a [COMMIT] and occurs within an 3519 ** explicit transaction then you should rollback the transaction before 3520 ** continuing. 3521 ** 3522 ** ^[SQLITE_DONE] means that the statement has finished executing 3523 ** successfully. sqlite3_step() should not be called again on this virtual 3524 ** machine without first calling [sqlite3_reset()] to reset the virtual 3525 ** machine back to its initial state. 3526 ** 3527 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3528 ** is returned each time a new row of data is ready for processing by the 3529 ** caller. The values may be accessed using the [column access functions]. 3530 ** sqlite3_step() is called again to retrieve the next row of data. 3531 ** 3532 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3533 ** violation) has occurred. sqlite3_step() should not be called again on 3534 ** the VM. More information may be found by calling [sqlite3_errmsg()]. 3535 ** ^With the legacy interface, a more specific error code (for example, 3536 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3537 ** can be obtained by calling [sqlite3_reset()] on the 3538 ** [prepared statement]. ^In the "v2" interface, 3539 ** the more specific error code is returned directly by sqlite3_step(). 3540 ** 3541 ** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3542 ** Perhaps it was called on a [prepared statement] that has 3543 ** already been [sqlite3_finalize | finalized] or on one that had 3544 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3545 ** be the case that the same database connection is being used by two or 3546 ** more threads at the same moment in time. 3547 ** 3548 ** For all versions of SQLite up to and including 3.6.23.1, a call to 3549 ** [sqlite3_reset()] was required after sqlite3_step() returned anything 3550 ** other than [SQLITE_ROW] before any subsequent invocation of 3551 ** sqlite3_step(). Failure to reset the prepared statement using 3552 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3553 ** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3554 ** calling [sqlite3_reset()] automatically in this circumstance rather 3555 ** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3556 ** break because any application that ever receives an SQLITE_MISUSE error 3557 ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3558 ** can be used to restore the legacy behavior. 3559 ** 3560 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3561 ** API always returns a generic error code, [SQLITE_ERROR], following any 3562 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3563 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3564 ** specific [error codes] that better describes the error. 3565 ** We admit that this is a goofy design. The problem has been fixed 3566 ** with the "v2" interface. If you prepare all of your SQL statements 3567 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3568 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3569 ** then the more specific [error codes] are returned directly 3570 ** by sqlite3_step(). The use of the "v2" interface is recommended. 3571 */ 3572 SQLITE_API int sqlite3_step(sqlite3_stmt*); 3573 3574 /* 3575 ** CAPI3REF: Number of columns in a result set 3576 ** 3577 ** ^The sqlite3_data_count(P) interface returns the number of columns in the 3578 ** current row of the result set of [prepared statement] P. 3579 ** ^If prepared statement P does not have results ready to return 3580 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3581 ** interfaces) then sqlite3_data_count(P) returns 0. 3582 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3583 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 3584 ** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 3585 ** will return non-zero if previous call to [sqlite3_step](P) returned 3586 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 3587 ** where it always returns zero since each step of that multi-step 3588 ** pragma returns 0 columns of data. 3589 ** 3590 ** See also: [sqlite3_column_count()] 3591 */ 3592 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt); 3593 3594 /* 3595 ** CAPI3REF: Fundamental Datatypes 3596 ** KEYWORDS: SQLITE_TEXT 3597 ** 3598 ** ^(Every value in SQLite has one of five fundamental datatypes: 3599 ** 3600 ** <ul> 3601 ** <li> 64-bit signed integer 3602 ** <li> 64-bit IEEE floating point number 3603 ** <li> string 3604 ** <li> BLOB 3605 ** <li> NULL 3606 ** </ul>)^ 3607 ** 3608 ** These constants are codes for each of those types. 3609 ** 3610 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3611 ** for a completely different meaning. Software that links against both 3612 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3613 ** SQLITE_TEXT. 3614 */ 3615 #define SQLITE_INTEGER 1 3616 #define SQLITE_FLOAT 2 3617 #define SQLITE_BLOB 4 3618 #define SQLITE_NULL 5 3619 #ifdef SQLITE_TEXT 3620 # undef SQLITE_TEXT 3621 #else 3622 # define SQLITE_TEXT 3 3623 #endif 3624 #define SQLITE3_TEXT 3 3625 3626 /* 3627 ** CAPI3REF: Result Values From A Query 3628 ** KEYWORDS: {column access functions} 3629 ** 3630 ** These routines form the "result set" interface. 3631 ** 3632 ** ^These routines return information about a single column of the current 3633 ** result row of a query. ^In every case the first argument is a pointer 3634 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3635 ** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3636 ** and the second argument is the index of the column for which information 3637 ** should be returned. ^The leftmost column of the result set has the index 0. 3638 ** ^The number of columns in the result can be determined using 3639 ** [sqlite3_column_count()]. 3640 ** 3641 ** If the SQL statement does not currently point to a valid row, or if the 3642 ** column index is out of range, the result is undefined. 3643 ** These routines may only be called when the most recent call to 3644 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3645 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3646 ** If any of these routines are called after [sqlite3_reset()] or 3647 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3648 ** something other than [SQLITE_ROW], the results are undefined. 3649 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3650 ** are called from a different thread while any of these routines 3651 ** are pending, then the results are undefined. 3652 ** 3653 ** ^The sqlite3_column_type() routine returns the 3654 ** [SQLITE_INTEGER | datatype code] for the initial data type 3655 ** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3656 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3657 ** returned by sqlite3_column_type() is only meaningful if no type 3658 ** conversions have occurred as described below. After a type conversion, 3659 ** the value returned by sqlite3_column_type() is undefined. Future 3660 ** versions of SQLite may change the behavior of sqlite3_column_type() 3661 ** following a type conversion. 3662 ** 3663 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3664 ** routine returns the number of bytes in that BLOB or string. 3665 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3666 ** the string to UTF-8 and then returns the number of bytes. 3667 ** ^If the result is a numeric value then sqlite3_column_bytes() uses 3668 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3669 ** the number of bytes in that string. 3670 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3671 ** 3672 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3673 ** routine returns the number of bytes in that BLOB or string. 3674 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3675 ** the string to UTF-16 and then returns the number of bytes. 3676 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3677 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3678 ** the number of bytes in that string. 3679 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3680 ** 3681 ** ^The values returned by [sqlite3_column_bytes()] and 3682 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3683 ** of the string. ^For clarity: the values returned by 3684 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3685 ** bytes in the string, not the number of characters. 3686 ** 3687 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3688 ** even empty strings, are always zero-terminated. ^The return 3689 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3690 ** 3691 ** ^The object returned by [sqlite3_column_value()] is an 3692 ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3693 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3694 ** If the [unprotected sqlite3_value] object returned by 3695 ** [sqlite3_column_value()] is used in any other way, including calls 3696 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3697 ** or [sqlite3_value_bytes()], then the behavior is undefined. 3698 ** 3699 ** These routines attempt to convert the value where appropriate. ^For 3700 ** example, if the internal representation is FLOAT and a text result 3701 ** is requested, [sqlite3_snprintf()] is used internally to perform the 3702 ** conversion automatically. ^(The following table details the conversions 3703 ** that are applied: 3704 ** 3705 ** <blockquote> 3706 ** <table border="1"> 3707 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3708 ** 3709 ** <tr><td> NULL <td> INTEGER <td> Result is 0 3710 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3711 ** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3712 ** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3713 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3714 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3715 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3716 ** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3717 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3718 ** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3719 ** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3720 ** <tr><td> TEXT <td> FLOAT <td> Use atof() 3721 ** <tr><td> TEXT <td> BLOB <td> No change 3722 ** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3723 ** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3724 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3725 ** </table> 3726 ** </blockquote>)^ 3727 ** 3728 ** The table above makes reference to standard C library functions atoi() 3729 ** and atof(). SQLite does not really use these functions. It has its 3730 ** own equivalent internal routines. The atoi() and atof() names are 3731 ** used in the table for brevity and because they are familiar to most 3732 ** C programmers. 3733 ** 3734 ** Note that when type conversions occur, pointers returned by prior 3735 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3736 ** sqlite3_column_text16() may be invalidated. 3737 ** Type conversions and pointer invalidations might occur 3738 ** in the following cases: 3739 ** 3740 ** <ul> 3741 ** <li> The initial content is a BLOB and sqlite3_column_text() or 3742 ** sqlite3_column_text16() is called. A zero-terminator might 3743 ** need to be added to the string.</li> 3744 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3745 ** sqlite3_column_text16() is called. The content must be converted 3746 ** to UTF-16.</li> 3747 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3748 ** sqlite3_column_text() is called. The content must be converted 3749 ** to UTF-8.</li> 3750 ** </ul> 3751 ** 3752 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3753 ** not invalidate a prior pointer, though of course the content of the buffer 3754 ** that the prior pointer references will have been modified. Other kinds 3755 ** of conversion are done in place when it is possible, but sometimes they 3756 ** are not possible and in those cases prior pointers are invalidated. 3757 ** 3758 ** The safest and easiest to remember policy is to invoke these routines 3759 ** in one of the following ways: 3760 ** 3761 ** <ul> 3762 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3763 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3764 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3765 ** </ul> 3766 ** 3767 ** In other words, you should call sqlite3_column_text(), 3768 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3769 ** into the desired format, then invoke sqlite3_column_bytes() or 3770 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3771 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3772 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3773 ** with calls to sqlite3_column_bytes(). 3774 ** 3775 ** ^The pointers returned are valid until a type conversion occurs as 3776 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3777 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3778 ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3779 ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3780 ** [sqlite3_free()]. 3781 ** 3782 ** ^(If a memory allocation error occurs during the evaluation of any 3783 ** of these routines, a default value is returned. The default value 3784 ** is either the integer 0, the floating point number 0.0, or a NULL 3785 ** pointer. Subsequent calls to [sqlite3_errcode()] will return 3786 ** [SQLITE_NOMEM].)^ 3787 */ 3788 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3789 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3790 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3791 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol); 3792 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol); 3793 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3794 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3795 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3796 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol); 3797 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3798 3799 /* 3800 ** CAPI3REF: Destroy A Prepared Statement Object 3801 ** 3802 ** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3803 ** ^If the most recent evaluation of the statement encountered no errors 3804 ** or if the statement is never been evaluated, then sqlite3_finalize() returns 3805 ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 3806 ** sqlite3_finalize(S) returns the appropriate [error code] or 3807 ** [extended error code]. 3808 ** 3809 ** ^The sqlite3_finalize(S) routine can be called at any point during 3810 ** the life cycle of [prepared statement] S: 3811 ** before statement S is ever evaluated, after 3812 ** one or more calls to [sqlite3_reset()], or after any call 3813 ** to [sqlite3_step()] regardless of whether or not the statement has 3814 ** completed execution. 3815 ** 3816 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 3817 ** 3818 ** The application must finalize every [prepared statement] in order to avoid 3819 ** resource leaks. It is a grievous error for the application to try to use 3820 ** a prepared statement after it has been finalized. Any use of a prepared 3821 ** statement after it has been finalized can result in undefined and 3822 ** undesirable behavior such as segfaults and heap corruption. 3823 */ 3824 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt); 3825 3826 /* 3827 ** CAPI3REF: Reset A Prepared Statement Object 3828 ** 3829 ** The sqlite3_reset() function is called to reset a [prepared statement] 3830 ** object back to its initial state, ready to be re-executed. 3831 ** ^Any SQL statement variables that had values bound to them using 3832 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3833 ** Use [sqlite3_clear_bindings()] to reset the bindings. 3834 ** 3835 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3836 ** back to the beginning of its program. 3837 ** 3838 ** ^If the most recent call to [sqlite3_step(S)] for the 3839 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3840 ** or if [sqlite3_step(S)] has never before been called on S, 3841 ** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3842 ** 3843 ** ^If the most recent call to [sqlite3_step(S)] for the 3844 ** [prepared statement] S indicated an error, then 3845 ** [sqlite3_reset(S)] returns an appropriate [error code]. 3846 ** 3847 ** ^The [sqlite3_reset(S)] interface does not change the values 3848 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3849 */ 3850 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt); 3851 3852 /* 3853 ** CAPI3REF: Create Or Redefine SQL Functions 3854 ** KEYWORDS: {function creation routines} 3855 ** KEYWORDS: {application-defined SQL function} 3856 ** KEYWORDS: {application-defined SQL functions} 3857 ** 3858 ** ^These functions (collectively known as "function creation routines") 3859 ** are used to add SQL functions or aggregates or to redefine the behavior 3860 ** of existing SQL functions or aggregates. The only differences between 3861 ** these routines are the text encoding expected for 3862 ** the second parameter (the name of the function being created) 3863 ** and the presence or absence of a destructor callback for 3864 ** the application data pointer. 3865 ** 3866 ** ^The first parameter is the [database connection] to which the SQL 3867 ** function is to be added. ^If an application uses more than one database 3868 ** connection then application-defined SQL functions must be added 3869 ** to each database connection separately. 3870 ** 3871 ** ^The second parameter is the name of the SQL function to be created or 3872 ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 3873 ** representation, exclusive of the zero-terminator. ^Note that the name 3874 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 3875 ** ^Any attempt to create a function with a longer name 3876 ** will result in [SQLITE_MISUSE] being returned. 3877 ** 3878 ** ^The third parameter (nArg) 3879 ** is the number of arguments that the SQL function or 3880 ** aggregate takes. ^If this parameter is -1, then the SQL function or 3881 ** aggregate may take any number of arguments between 0 and the limit 3882 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3883 ** parameter is less than -1 or greater than 127 then the behavior is 3884 ** undefined. 3885 ** 3886 ** ^The fourth parameter, eTextRep, specifies what 3887 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3888 ** its parameters. Every SQL function implementation must be able to work 3889 ** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3890 ** more efficient with one encoding than another. ^An application may 3891 ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3892 ** times with the same function but with different values of eTextRep. 3893 ** ^When multiple implementations of the same function are available, SQLite 3894 ** will pick the one that involves the least amount of data conversion. 3895 ** If there is only a single implementation which does not care what text 3896 ** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3897 ** 3898 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3899 ** function can gain access to this pointer using [sqlite3_user_data()].)^ 3900 ** 3901 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 3902 ** pointers to C-language functions that implement the SQL function or 3903 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3904 ** callback only; NULL pointers must be passed as the xStep and xFinal 3905 ** parameters. ^An aggregate SQL function requires an implementation of xStep 3906 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 3907 ** SQL function or aggregate, pass NULL pointers for all three function 3908 ** callbacks. 3909 ** 3910 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 3911 ** then it is destructor for the application data pointer. 3912 ** The destructor is invoked when the function is deleted, either by being 3913 ** overloaded or when the database connection closes.)^ 3914 ** ^The destructor is also invoked if the call to 3915 ** sqlite3_create_function_v2() fails. 3916 ** ^When the destructor callback of the tenth parameter is invoked, it 3917 ** is passed a single argument which is a copy of the application data 3918 ** pointer which was the fifth parameter to sqlite3_create_function_v2(). 3919 ** 3920 ** ^It is permitted to register multiple implementations of the same 3921 ** functions with the same name but with either differing numbers of 3922 ** arguments or differing preferred text encodings. ^SQLite will use 3923 ** the implementation that most closely matches the way in which the 3924 ** SQL function is used. ^A function implementation with a non-negative 3925 ** nArg parameter is a better match than a function implementation with 3926 ** a negative nArg. ^A function where the preferred text encoding 3927 ** matches the database encoding is a better 3928 ** match than a function where the encoding is different. 3929 ** ^A function where the encoding difference is between UTF16le and UTF16be 3930 ** is a closer match than a function where the encoding difference is 3931 ** between UTF8 and UTF16. 3932 ** 3933 ** ^Built-in functions may be overloaded by new application-defined functions. 3934 ** 3935 ** ^An application-defined function is permitted to call other 3936 ** SQLite interfaces. However, such calls must not 3937 ** close the database connection nor finalize or reset the prepared 3938 ** statement in which the function is running. 3939 */ 3940 SQLITE_API int sqlite3_create_function( 3941 sqlite3 *db, 3942 const char *zFunctionName, 3943 int nArg, 3944 int eTextRep, 3945 void *pApp, 3946 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3947 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3948 void (*xFinal)(sqlite3_context*) 3949 ); 3950 SQLITE_API int sqlite3_create_function16( 3951 sqlite3 *db, 3952 const void *zFunctionName, 3953 int nArg, 3954 int eTextRep, 3955 void *pApp, 3956 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3957 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3958 void (*xFinal)(sqlite3_context*) 3959 ); 3960 SQLITE_API int sqlite3_create_function_v2( 3961 sqlite3 *db, 3962 const char *zFunctionName, 3963 int nArg, 3964 int eTextRep, 3965 void *pApp, 3966 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3967 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3968 void (*xFinal)(sqlite3_context*), 3969 void(*xDestroy)(void*) 3970 ); 3971 3972 /* 3973 ** CAPI3REF: Text Encodings 3974 ** 3975 ** These constant define integer codes that represent the various 3976 ** text encodings supported by SQLite. 3977 */ 3978 #define SQLITE_UTF8 1 3979 #define SQLITE_UTF16LE 2 3980 #define SQLITE_UTF16BE 3 3981 #define SQLITE_UTF16 4 /* Use native byte order */ 3982 #define SQLITE_ANY 5 /* sqlite3_create_function only */ 3983 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3984 3985 /* 3986 ** CAPI3REF: Deprecated Functions 3987 ** DEPRECATED 3988 ** 3989 ** These functions are [deprecated]. In order to maintain 3990 ** backwards compatibility with older code, these functions continue 3991 ** to be supported. However, new applications should avoid 3992 ** the use of these functions. To help encourage people to avoid 3993 ** using these functions, we are not going to tell you what they do. 3994 */ 3995 #ifndef SQLITE_OMIT_DEPRECATED 3996 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3997 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3998 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3999 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void); 4000 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4001 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4002 void*,sqlite3_int64); 4003 #endif 4004 4005 /* 4006 ** CAPI3REF: Obtaining SQL Function Parameter Values 4007 ** 4008 ** The C-language implementation of SQL functions and aggregates uses 4009 ** this set of interface routines to access the parameter values on 4010 ** the function or aggregate. 4011 ** 4012 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters 4013 ** to [sqlite3_create_function()] and [sqlite3_create_function16()] 4014 ** define callbacks that implement the SQL functions and aggregates. 4015 ** The 3rd parameter to these callbacks is an array of pointers to 4016 ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 4017 ** each parameter to the SQL function. These routines are used to 4018 ** extract values from the [sqlite3_value] objects. 4019 ** 4020 ** These routines work only with [protected sqlite3_value] objects. 4021 ** Any attempt to use these routines on an [unprotected sqlite3_value] 4022 ** object results in undefined behavior. 4023 ** 4024 ** ^These routines work just like the corresponding [column access functions] 4025 ** except that these routines take a single [protected sqlite3_value] object 4026 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4027 ** 4028 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4029 ** in the native byte-order of the host machine. ^The 4030 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4031 ** extract UTF-16 strings as big-endian and little-endian respectively. 4032 ** 4033 ** ^(The sqlite3_value_numeric_type() interface attempts to apply 4034 ** numeric affinity to the value. This means that an attempt is 4035 ** made to convert the value to an integer or floating point. If 4036 ** such a conversion is possible without loss of information (in other 4037 ** words, if the value is a string that looks like a number) 4038 ** then the conversion is performed. Otherwise no conversion occurs. 4039 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4040 ** 4041 ** Please pay particular attention to the fact that the pointer returned 4042 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4043 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4044 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4045 ** or [sqlite3_value_text16()]. 4046 ** 4047 ** These routines must be called from the same thread as 4048 ** the SQL function that supplied the [sqlite3_value*] parameters. 4049 */ 4050 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*); 4051 SQLITE_API int sqlite3_value_bytes(sqlite3_value*); 4052 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*); 4053 SQLITE_API double sqlite3_value_double(sqlite3_value*); 4054 SQLITE_API int sqlite3_value_int(sqlite3_value*); 4055 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4056 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*); 4057 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*); 4058 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*); 4059 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*); 4060 SQLITE_API int sqlite3_value_type(sqlite3_value*); 4061 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*); 4062 4063 /* 4064 ** CAPI3REF: Obtain Aggregate Function Context 4065 ** 4066 ** Implementations of aggregate SQL functions use this 4067 ** routine to allocate memory for storing their state. 4068 ** 4069 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4070 ** for a particular aggregate function, SQLite 4071 ** allocates N of memory, zeroes out that memory, and returns a pointer 4072 ** to the new memory. ^On second and subsequent calls to 4073 ** sqlite3_aggregate_context() for the same aggregate function instance, 4074 ** the same buffer is returned. Sqlite3_aggregate_context() is normally 4075 ** called once for each invocation of the xStep callback and then one 4076 ** last time when the xFinal callback is invoked. ^(When no rows match 4077 ** an aggregate query, the xStep() callback of the aggregate function 4078 ** implementation is never called and xFinal() is called exactly once. 4079 ** In those cases, sqlite3_aggregate_context() might be called for the 4080 ** first time from within xFinal().)^ 4081 ** 4082 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4083 ** when first called if N is less than or equal to zero or if a memory 4084 ** allocate error occurs. 4085 ** 4086 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4087 ** determined by the N parameter on first successful call. Changing the 4088 ** value of N in subsequent call to sqlite3_aggregate_context() within 4089 ** the same aggregate function instance will not resize the memory 4090 ** allocation.)^ Within the xFinal callback, it is customary to set 4091 ** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4092 ** pointless memory allocations occur. 4093 ** 4094 ** ^SQLite automatically frees the memory allocated by 4095 ** sqlite3_aggregate_context() when the aggregate query concludes. 4096 ** 4097 ** The first parameter must be a copy of the 4098 ** [sqlite3_context | SQL function context] that is the first parameter 4099 ** to the xStep or xFinal callback routine that implements the aggregate 4100 ** function. 4101 ** 4102 ** This routine must be called from the same thread in which 4103 ** the aggregate SQL function is running. 4104 */ 4105 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4106 4107 /* 4108 ** CAPI3REF: User Data For Functions 4109 ** 4110 ** ^The sqlite3_user_data() interface returns a copy of 4111 ** the pointer that was the pUserData parameter (the 5th parameter) 4112 ** of the [sqlite3_create_function()] 4113 ** and [sqlite3_create_function16()] routines that originally 4114 ** registered the application defined function. 4115 ** 4116 ** This routine must be called from the same thread in which 4117 ** the application-defined function is running. 4118 */ 4119 SQLITE_API void *sqlite3_user_data(sqlite3_context*); 4120 4121 /* 4122 ** CAPI3REF: Database Connection For Functions 4123 ** 4124 ** ^The sqlite3_context_db_handle() interface returns a copy of 4125 ** the pointer to the [database connection] (the 1st parameter) 4126 ** of the [sqlite3_create_function()] 4127 ** and [sqlite3_create_function16()] routines that originally 4128 ** registered the application defined function. 4129 */ 4130 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4131 4132 /* 4133 ** CAPI3REF: Function Auxiliary Data 4134 ** 4135 ** The following two functions may be used by scalar SQL functions to 4136 ** associate metadata with argument values. If the same value is passed to 4137 ** multiple invocations of the same SQL function during query execution, under 4138 ** some circumstances the associated metadata may be preserved. This may 4139 ** be used, for example, to add a regular-expression matching scalar 4140 ** function. The compiled version of the regular expression is stored as 4141 ** metadata associated with the SQL value passed as the regular expression 4142 ** pattern. The compiled regular expression can be reused on multiple 4143 ** invocations of the same function so that the original pattern string 4144 ** does not need to be recompiled on each invocation. 4145 ** 4146 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4147 ** associated by the sqlite3_set_auxdata() function with the Nth argument 4148 ** value to the application-defined function. ^If no metadata has been ever 4149 ** been set for the Nth argument of the function, or if the corresponding 4150 ** function parameter has changed since the meta-data was set, 4151 ** then sqlite3_get_auxdata() returns a NULL pointer. 4152 ** 4153 ** ^The sqlite3_set_auxdata() interface saves the metadata 4154 ** pointed to by its 3rd parameter as the metadata for the N-th 4155 ** argument of the application-defined function. Subsequent 4156 ** calls to sqlite3_get_auxdata() might return this data, if it has 4157 ** not been destroyed. 4158 ** ^If it is not NULL, SQLite will invoke the destructor 4159 ** function given by the 4th parameter to sqlite3_set_auxdata() on 4160 ** the metadata when the corresponding function parameter changes 4161 ** or when the SQL statement completes, whichever comes first. 4162 ** 4163 ** SQLite is free to call the destructor and drop metadata on any 4164 ** parameter of any function at any time. ^The only guarantee is that 4165 ** the destructor will be called before the metadata is dropped. 4166 ** 4167 ** ^(In practice, metadata is preserved between function calls for 4168 ** expressions that are constant at compile time. This includes literal 4169 ** values and [parameters].)^ 4170 ** 4171 ** These routines must be called from the same thread in which 4172 ** the SQL function is running. 4173 */ 4174 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N); 4175 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4176 4177 4178 /* 4179 ** CAPI3REF: Constants Defining Special Destructor Behavior 4180 ** 4181 ** These are special values for the destructor that is passed in as the 4182 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4183 ** argument is SQLITE_STATIC, it means that the content pointer is constant 4184 ** and will never change. It does not need to be destroyed. ^The 4185 ** SQLITE_TRANSIENT value means that the content will likely change in 4186 ** the near future and that SQLite should make its own private copy of 4187 ** the content before returning. 4188 ** 4189 ** The typedef is necessary to work around problems in certain 4190 ** C++ compilers. See ticket #2191. 4191 */ 4192 typedef void (*sqlite3_destructor_type)(void*); 4193 #define SQLITE_STATIC ((sqlite3_destructor_type)0) 4194 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4195 4196 /* 4197 ** CAPI3REF: Setting The Result Of An SQL Function 4198 ** 4199 ** These routines are used by the xFunc or xFinal callbacks that 4200 ** implement SQL functions and aggregates. See 4201 ** [sqlite3_create_function()] and [sqlite3_create_function16()] 4202 ** for additional information. 4203 ** 4204 ** These functions work very much like the [parameter binding] family of 4205 ** functions used to bind values to host parameters in prepared statements. 4206 ** Refer to the [SQL parameter] documentation for additional information. 4207 ** 4208 ** ^The sqlite3_result_blob() interface sets the result from 4209 ** an application-defined function to be the BLOB whose content is pointed 4210 ** to by the second parameter and which is N bytes long where N is the 4211 ** third parameter. 4212 ** 4213 ** ^The sqlite3_result_zeroblob() interfaces set the result of 4214 ** the application-defined function to be a BLOB containing all zero 4215 ** bytes and N bytes in size, where N is the value of the 2nd parameter. 4216 ** 4217 ** ^The sqlite3_result_double() interface sets the result from 4218 ** an application-defined function to be a floating point value specified 4219 ** by its 2nd argument. 4220 ** 4221 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4222 ** cause the implemented SQL function to throw an exception. 4223 ** ^SQLite uses the string pointed to by the 4224 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4225 ** as the text of an error message. ^SQLite interprets the error 4226 ** message string from sqlite3_result_error() as UTF-8. ^SQLite 4227 ** interprets the string from sqlite3_result_error16() as UTF-16 in native 4228 ** byte order. ^If the third parameter to sqlite3_result_error() 4229 ** or sqlite3_result_error16() is negative then SQLite takes as the error 4230 ** message all text up through the first zero character. 4231 ** ^If the third parameter to sqlite3_result_error() or 4232 ** sqlite3_result_error16() is non-negative then SQLite takes that many 4233 ** bytes (not characters) from the 2nd parameter as the error message. 4234 ** ^The sqlite3_result_error() and sqlite3_result_error16() 4235 ** routines make a private copy of the error message text before 4236 ** they return. Hence, the calling function can deallocate or 4237 ** modify the text after they return without harm. 4238 ** ^The sqlite3_result_error_code() function changes the error code 4239 ** returned by SQLite as a result of an error in a function. ^By default, 4240 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4241 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4242 ** 4243 ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 4244 ** error indicating that a string or BLOB is too long to represent. 4245 ** 4246 ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 4247 ** error indicating that a memory allocation failed. 4248 ** 4249 ** ^The sqlite3_result_int() interface sets the return value 4250 ** of the application-defined function to be the 32-bit signed integer 4251 ** value given in the 2nd argument. 4252 ** ^The sqlite3_result_int64() interface sets the return value 4253 ** of the application-defined function to be the 64-bit signed integer 4254 ** value given in the 2nd argument. 4255 ** 4256 ** ^The sqlite3_result_null() interface sets the return value 4257 ** of the application-defined function to be NULL. 4258 ** 4259 ** ^The sqlite3_result_text(), sqlite3_result_text16(), 4260 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4261 ** set the return value of the application-defined function to be 4262 ** a text string which is represented as UTF-8, UTF-16 native byte order, 4263 ** UTF-16 little endian, or UTF-16 big endian, respectively. 4264 ** ^SQLite takes the text result from the application from 4265 ** the 2nd parameter of the sqlite3_result_text* interfaces. 4266 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4267 ** is negative, then SQLite takes result text from the 2nd parameter 4268 ** through the first zero character. 4269 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4270 ** is non-negative, then as many bytes (not characters) of the text 4271 ** pointed to by the 2nd parameter are taken as the application-defined 4272 ** function result. If the 3rd parameter is non-negative, then it 4273 ** must be the byte offset into the string where the NUL terminator would 4274 ** appear if the string where NUL terminated. If any NUL characters occur 4275 ** in the string at a byte offset that is less than the value of the 3rd 4276 ** parameter, then the resulting string will contain embedded NULs and the 4277 ** result of expressions operating on strings with embedded NULs is undefined. 4278 ** ^If the 4th parameter to the sqlite3_result_text* interfaces 4279 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4280 ** function as the destructor on the text or BLOB result when it has 4281 ** finished using that result. 4282 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4283 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4284 ** assumes that the text or BLOB result is in constant space and does not 4285 ** copy the content of the parameter nor call a destructor on the content 4286 ** when it has finished using that result. 4287 ** ^If the 4th parameter to the sqlite3_result_text* interfaces 4288 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4289 ** then SQLite makes a copy of the result into space obtained from 4290 ** from [sqlite3_malloc()] before it returns. 4291 ** 4292 ** ^The sqlite3_result_value() interface sets the result of 4293 ** the application-defined function to be a copy the 4294 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4295 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4296 ** so that the [sqlite3_value] specified in the parameter may change or 4297 ** be deallocated after sqlite3_result_value() returns without harm. 4298 ** ^A [protected sqlite3_value] object may always be used where an 4299 ** [unprotected sqlite3_value] object is required, so either 4300 ** kind of [sqlite3_value] object can be used with this interface. 4301 ** 4302 ** If these routines are called from within the different thread 4303 ** than the one containing the application-defined function that received 4304 ** the [sqlite3_context] pointer, the results are undefined. 4305 */ 4306 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4307 SQLITE_API void sqlite3_result_double(sqlite3_context*, double); 4308 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int); 4309 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int); 4310 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*); 4311 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*); 4312 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int); 4313 SQLITE_API void sqlite3_result_int(sqlite3_context*, int); 4314 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4315 SQLITE_API void sqlite3_result_null(sqlite3_context*); 4316 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4317 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4318 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4319 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4320 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4321 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n); 4322 4323 /* 4324 ** CAPI3REF: Define New Collating Sequences 4325 ** 4326 ** ^These functions add, remove, or modify a [collation] associated 4327 ** with the [database connection] specified as the first argument. 4328 ** 4329 ** ^The name of the collation is a UTF-8 string 4330 ** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4331 ** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4332 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4333 ** considered to be the same name. 4334 ** 4335 ** ^(The third argument (eTextRep) must be one of the constants: 4336 ** <ul> 4337 ** <li> [SQLITE_UTF8], 4338 ** <li> [SQLITE_UTF16LE], 4339 ** <li> [SQLITE_UTF16BE], 4340 ** <li> [SQLITE_UTF16], or 4341 ** <li> [SQLITE_UTF16_ALIGNED]. 4342 ** </ul>)^ 4343 ** ^The eTextRep argument determines the encoding of strings passed 4344 ** to the collating function callback, xCallback. 4345 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4346 ** force strings to be UTF16 with native byte order. 4347 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4348 ** on an even byte address. 4349 ** 4350 ** ^The fourth argument, pArg, is an application data pointer that is passed 4351 ** through as the first argument to the collating function callback. 4352 ** 4353 ** ^The fifth argument, xCallback, is a pointer to the collating function. 4354 ** ^Multiple collating functions can be registered using the same name but 4355 ** with different eTextRep parameters and SQLite will use whichever 4356 ** function requires the least amount of data transformation. 4357 ** ^If the xCallback argument is NULL then the collating function is 4358 ** deleted. ^When all collating functions having the same name are deleted, 4359 ** that collation is no longer usable. 4360 ** 4361 ** ^The collating function callback is invoked with a copy of the pArg 4362 ** application data pointer and with two strings in the encoding specified 4363 ** by the eTextRep argument. The collating function must return an 4364 ** integer that is negative, zero, or positive 4365 ** if the first string is less than, equal to, or greater than the second, 4366 ** respectively. A collating function must always return the same answer 4367 ** given the same inputs. If two or more collating functions are registered 4368 ** to the same collation name (using different eTextRep values) then all 4369 ** must give an equivalent answer when invoked with equivalent strings. 4370 ** The collating function must obey the following properties for all 4371 ** strings A, B, and C: 4372 ** 4373 ** <ol> 4374 ** <li> If A==B then B==A. 4375 ** <li> If A==B and B==C then A==C. 4376 ** <li> If A<B THEN B>A. 4377 ** <li> If A<B and B<C then A<C. 4378 ** </ol> 4379 ** 4380 ** If a collating function fails any of the above constraints and that 4381 ** collating function is registered and used, then the behavior of SQLite 4382 ** is undefined. 4383 ** 4384 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4385 ** with the addition that the xDestroy callback is invoked on pArg when 4386 ** the collating function is deleted. 4387 ** ^Collating functions are deleted when they are overridden by later 4388 ** calls to the collation creation functions or when the 4389 ** [database connection] is closed using [sqlite3_close()]. 4390 ** 4391 ** ^The xDestroy callback is <u>not</u> called if the 4392 ** sqlite3_create_collation_v2() function fails. Applications that invoke 4393 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4394 ** check the return code and dispose of the application data pointer 4395 ** themselves rather than expecting SQLite to deal with it for them. 4396 ** This is different from every other SQLite interface. The inconsistency 4397 ** is unfortunate but cannot be changed without breaking backwards 4398 ** compatibility. 4399 ** 4400 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4401 */ 4402 SQLITE_API int sqlite3_create_collation( 4403 sqlite3*, 4404 const char *zName, 4405 int eTextRep, 4406 void *pArg, 4407 int(*xCompare)(void*,int,const void*,int,const void*) 4408 ); 4409 SQLITE_API int sqlite3_create_collation_v2( 4410 sqlite3*, 4411 const char *zName, 4412 int eTextRep, 4413 void *pArg, 4414 int(*xCompare)(void*,int,const void*,int,const void*), 4415 void(*xDestroy)(void*) 4416 ); 4417 SQLITE_API int sqlite3_create_collation16( 4418 sqlite3*, 4419 const void *zName, 4420 int eTextRep, 4421 void *pArg, 4422 int(*xCompare)(void*,int,const void*,int,const void*) 4423 ); 4424 4425 /* 4426 ** CAPI3REF: Collation Needed Callbacks 4427 ** 4428 ** ^To avoid having to register all collation sequences before a database 4429 ** can be used, a single callback function may be registered with the 4430 ** [database connection] to be invoked whenever an undefined collation 4431 ** sequence is required. 4432 ** 4433 ** ^If the function is registered using the sqlite3_collation_needed() API, 4434 ** then it is passed the names of undefined collation sequences as strings 4435 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4436 ** the names are passed as UTF-16 in machine native byte order. 4437 ** ^A call to either function replaces the existing collation-needed callback. 4438 ** 4439 ** ^(When the callback is invoked, the first argument passed is a copy 4440 ** of the second argument to sqlite3_collation_needed() or 4441 ** sqlite3_collation_needed16(). The second argument is the database 4442 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4443 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4444 ** sequence function required. The fourth parameter is the name of the 4445 ** required collation sequence.)^ 4446 ** 4447 ** The callback function should register the desired collation using 4448 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4449 ** [sqlite3_create_collation_v2()]. 4450 */ 4451 SQLITE_API int sqlite3_collation_needed( 4452 sqlite3*, 4453 void*, 4454 void(*)(void*,sqlite3*,int eTextRep,const char*) 4455 ); 4456 SQLITE_API int sqlite3_collation_needed16( 4457 sqlite3*, 4458 void*, 4459 void(*)(void*,sqlite3*,int eTextRep,const void*) 4460 ); 4461 4462 #ifdef SQLITE_HAS_CODEC 4463 /* 4464 ** Specify the key for an encrypted database. This routine should be 4465 ** called right after sqlite3_open(). 4466 ** 4467 ** The code to implement this API is not available in the public release 4468 ** of SQLite. 4469 */ 4470 SQLITE_API int sqlite3_key( 4471 sqlite3 *db, /* Database to be rekeyed */ 4472 const void *pKey, int nKey /* The key */ 4473 ); 4474 4475 /* 4476 ** Change the key on an open database. If the current database is not 4477 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4478 ** database is decrypted. 4479 ** 4480 ** The code to implement this API is not available in the public release 4481 ** of SQLite. 4482 */ 4483 SQLITE_API int sqlite3_rekey( 4484 sqlite3 *db, /* Database to be rekeyed */ 4485 const void *pKey, int nKey /* The new key */ 4486 ); 4487 4488 /* 4489 ** Specify the activation key for a SEE database. Unless 4490 ** activated, none of the SEE routines will work. 4491 */ 4492 SQLITE_API void sqlite3_activate_see( 4493 const char *zPassPhrase /* Activation phrase */ 4494 ); 4495 #endif 4496 4497 #ifdef SQLITE_ENABLE_CEROD 4498 /* 4499 ** Specify the activation key for a CEROD database. Unless 4500 ** activated, none of the CEROD routines will work. 4501 */ 4502 SQLITE_API void sqlite3_activate_cerod( 4503 const char *zPassPhrase /* Activation phrase */ 4504 ); 4505 #endif 4506 4507 /* 4508 ** CAPI3REF: Suspend Execution For A Short Time 4509 ** 4510 ** The sqlite3_sleep() function causes the current thread to suspend execution 4511 ** for at least a number of milliseconds specified in its parameter. 4512 ** 4513 ** If the operating system does not support sleep requests with 4514 ** millisecond time resolution, then the time will be rounded up to 4515 ** the nearest second. The number of milliseconds of sleep actually 4516 ** requested from the operating system is returned. 4517 ** 4518 ** ^SQLite implements this interface by calling the xSleep() 4519 ** method of the default [sqlite3_vfs] object. If the xSleep() method 4520 ** of the default VFS is not implemented correctly, or not implemented at 4521 ** all, then the behavior of sqlite3_sleep() may deviate from the description 4522 ** in the previous paragraphs. 4523 */ 4524 SQLITE_API int sqlite3_sleep(int); 4525 4526 /* 4527 ** CAPI3REF: Name Of The Folder Holding Temporary Files 4528 ** 4529 ** ^(If this global variable is made to point to a string which is 4530 ** the name of a folder (a.k.a. directory), then all temporary files 4531 ** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4532 ** will be placed in that directory.)^ ^If this variable 4533 ** is a NULL pointer, then SQLite performs a search for an appropriate 4534 ** temporary file directory. 4535 ** 4536 ** It is not safe to read or modify this variable in more than one 4537 ** thread at a time. It is not safe to read or modify this variable 4538 ** if a [database connection] is being used at the same time in a separate 4539 ** thread. 4540 ** It is intended that this variable be set once 4541 ** as part of process initialization and before any SQLite interface 4542 ** routines have been called and that this variable remain unchanged 4543 ** thereafter. 4544 ** 4545 ** ^The [temp_store_directory pragma] may modify this variable and cause 4546 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4547 ** the [temp_store_directory pragma] always assumes that any string 4548 ** that this variable points to is held in memory obtained from 4549 ** [sqlite3_malloc] and the pragma may attempt to free that memory 4550 ** using [sqlite3_free]. 4551 ** Hence, if this variable is modified directly, either it should be 4552 ** made NULL or made to point to memory obtained from [sqlite3_malloc] 4553 ** or else the use of the [temp_store_directory pragma] should be avoided. 4554 ** 4555 ** <b>Note to Windows Runtime users:</b> The temporary directory must be set 4556 ** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 4557 ** features that require the use of temporary files may fail. Here is an 4558 ** example of how to do this using C++ with the Windows Runtime: 4559 ** 4560 ** <blockquote><pre> 4561 ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 4562 ** TemporaryFolder->Path->Data(); 4563 ** char zPathBuf[MAX_PATH + 1]; 4564 ** memset(zPathBuf, 0, sizeof(zPathBuf)); 4565 ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 4566 ** NULL, NULL); 4567 ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 4568 ** </pre></blockquote> 4569 */ 4570 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory; 4571 4572 /* 4573 ** CAPI3REF: Name Of The Folder Holding Database Files 4574 ** 4575 ** ^(If this global variable is made to point to a string which is 4576 ** the name of a folder (a.k.a. directory), then all database files 4577 ** specified with a relative pathname and created or accessed by 4578 ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 4579 ** to be relative to that directory.)^ ^If this variable is a NULL 4580 ** pointer, then SQLite assumes that all database files specified 4581 ** with a relative pathname are relative to the current directory 4582 ** for the process. Only the windows VFS makes use of this global 4583 ** variable; it is ignored by the unix VFS. 4584 ** 4585 ** Changing the value of this variable while a database connection is 4586 ** open can result in a corrupt database. 4587 ** 4588 ** It is not safe to read or modify this variable in more than one 4589 ** thread at a time. It is not safe to read or modify this variable 4590 ** if a [database connection] is being used at the same time in a separate 4591 ** thread. 4592 ** It is intended that this variable be set once 4593 ** as part of process initialization and before any SQLite interface 4594 ** routines have been called and that this variable remain unchanged 4595 ** thereafter. 4596 ** 4597 ** ^The [data_store_directory pragma] may modify this variable and cause 4598 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4599 ** the [data_store_directory pragma] always assumes that any string 4600 ** that this variable points to is held in memory obtained from 4601 ** [sqlite3_malloc] and the pragma may attempt to free that memory 4602 ** using [sqlite3_free]. 4603 ** Hence, if this variable is modified directly, either it should be 4604 ** made NULL or made to point to memory obtained from [sqlite3_malloc] 4605 ** or else the use of the [data_store_directory pragma] should be avoided. 4606 */ 4607 SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory; 4608 4609 /* 4610 ** CAPI3REF: Test For Auto-Commit Mode 4611 ** KEYWORDS: {autocommit mode} 4612 ** 4613 ** ^The sqlite3_get_autocommit() interface returns non-zero or 4614 ** zero if the given database connection is or is not in autocommit mode, 4615 ** respectively. ^Autocommit mode is on by default. 4616 ** ^Autocommit mode is disabled by a [BEGIN] statement. 4617 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 4618 ** 4619 ** If certain kinds of errors occur on a statement within a multi-statement 4620 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 4621 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 4622 ** transaction might be rolled back automatically. The only way to 4623 ** find out whether SQLite automatically rolled back the transaction after 4624 ** an error is to use this function. 4625 ** 4626 ** If another thread changes the autocommit status of the database 4627 ** connection while this routine is running, then the return value 4628 ** is undefined. 4629 */ 4630 SQLITE_API int sqlite3_get_autocommit(sqlite3*); 4631 4632 /* 4633 ** CAPI3REF: Find The Database Handle Of A Prepared Statement 4634 ** 4635 ** ^The sqlite3_db_handle interface returns the [database connection] handle 4636 ** to which a [prepared statement] belongs. ^The [database connection] 4637 ** returned by sqlite3_db_handle is the same [database connection] 4638 ** that was the first argument 4639 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 4640 ** create the statement in the first place. 4641 */ 4642 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 4643 4644 /* 4645 ** CAPI3REF: Return The Filename For A Database Connection 4646 ** 4647 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 4648 ** associated with database N of connection D. ^The main database file 4649 ** has the name "main". If there is no attached database N on the database 4650 ** connection D, or if database N is a temporary or in-memory database, then 4651 ** a NULL pointer is returned. 4652 ** 4653 ** ^The filename returned by this function is the output of the 4654 ** xFullPathname method of the [VFS]. ^In other words, the filename 4655 ** will be an absolute pathname, even if the filename used 4656 ** to open the database originally was a URI or relative pathname. 4657 */ 4658 SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 4659 4660 /* 4661 ** CAPI3REF: Determine if a database is read-only 4662 ** 4663 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 4664 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not 4665 ** the name of a database on connection D. 4666 */ 4667 SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 4668 4669 /* 4670 ** CAPI3REF: Find the next prepared statement 4671 ** 4672 ** ^This interface returns a pointer to the next [prepared statement] after 4673 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 4674 ** then this interface returns a pointer to the first prepared statement 4675 ** associated with the database connection pDb. ^If no prepared statement 4676 ** satisfies the conditions of this routine, it returns NULL. 4677 ** 4678 ** The [database connection] pointer D in a call to 4679 ** [sqlite3_next_stmt(D,S)] must refer to an open database 4680 ** connection and in particular must not be a NULL pointer. 4681 */ 4682 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 4683 4684 /* 4685 ** CAPI3REF: Commit And Rollback Notification Callbacks 4686 ** 4687 ** ^The sqlite3_commit_hook() interface registers a callback 4688 ** function to be invoked whenever a transaction is [COMMIT | committed]. 4689 ** ^Any callback set by a previous call to sqlite3_commit_hook() 4690 ** for the same database connection is overridden. 4691 ** ^The sqlite3_rollback_hook() interface registers a callback 4692 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 4693 ** ^Any callback set by a previous call to sqlite3_rollback_hook() 4694 ** for the same database connection is overridden. 4695 ** ^The pArg argument is passed through to the callback. 4696 ** ^If the callback on a commit hook function returns non-zero, 4697 ** then the commit is converted into a rollback. 4698 ** 4699 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 4700 ** return the P argument from the previous call of the same function 4701 ** on the same [database connection] D, or NULL for 4702 ** the first call for each function on D. 4703 ** 4704 ** The commit and rollback hook callbacks are not reentrant. 4705 ** The callback implementation must not do anything that will modify 4706 ** the database connection that invoked the callback. Any actions 4707 ** to modify the database connection must be deferred until after the 4708 ** completion of the [sqlite3_step()] call that triggered the commit 4709 ** or rollback hook in the first place. 4710 ** Note that running any other SQL statements, including SELECT statements, 4711 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 4712 ** the database connections for the meaning of "modify" in this paragraph. 4713 ** 4714 ** ^Registering a NULL function disables the callback. 4715 ** 4716 ** ^When the commit hook callback routine returns zero, the [COMMIT] 4717 ** operation is allowed to continue normally. ^If the commit hook 4718 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 4719 ** ^The rollback hook is invoked on a rollback that results from a commit 4720 ** hook returning non-zero, just as it would be with any other rollback. 4721 ** 4722 ** ^For the purposes of this API, a transaction is said to have been 4723 ** rolled back if an explicit "ROLLBACK" statement is executed, or 4724 ** an error or constraint causes an implicit rollback to occur. 4725 ** ^The rollback callback is not invoked if a transaction is 4726 ** automatically rolled back because the database connection is closed. 4727 ** 4728 ** See also the [sqlite3_update_hook()] interface. 4729 */ 4730 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 4731 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 4732 4733 /* 4734 ** CAPI3REF: Data Change Notification Callbacks 4735 ** 4736 ** ^The sqlite3_update_hook() interface registers a callback function 4737 ** with the [database connection] identified by the first argument 4738 ** to be invoked whenever a row is updated, inserted or deleted. 4739 ** ^Any callback set by a previous call to this function 4740 ** for the same database connection is overridden. 4741 ** 4742 ** ^The second argument is a pointer to the function to invoke when a 4743 ** row is updated, inserted or deleted. 4744 ** ^The first argument to the callback is a copy of the third argument 4745 ** to sqlite3_update_hook(). 4746 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 4747 ** or [SQLITE_UPDATE], depending on the operation that caused the callback 4748 ** to be invoked. 4749 ** ^The third and fourth arguments to the callback contain pointers to the 4750 ** database and table name containing the affected row. 4751 ** ^The final callback parameter is the [rowid] of the row. 4752 ** ^In the case of an update, this is the [rowid] after the update takes place. 4753 ** 4754 ** ^(The update hook is not invoked when internal system tables are 4755 ** modified (i.e. sqlite_master and sqlite_sequence).)^ 4756 ** 4757 ** ^In the current implementation, the update hook 4758 ** is not invoked when duplication rows are deleted because of an 4759 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 4760 ** invoked when rows are deleted using the [truncate optimization]. 4761 ** The exceptions defined in this paragraph might change in a future 4762 ** release of SQLite. 4763 ** 4764 ** The update hook implementation must not do anything that will modify 4765 ** the database connection that invoked the update hook. Any actions 4766 ** to modify the database connection must be deferred until after the 4767 ** completion of the [sqlite3_step()] call that triggered the update hook. 4768 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4769 ** database connections for the meaning of "modify" in this paragraph. 4770 ** 4771 ** ^The sqlite3_update_hook(D,C,P) function 4772 ** returns the P argument from the previous call 4773 ** on the same [database connection] D, or NULL for 4774 ** the first call on D. 4775 ** 4776 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4777 ** interfaces. 4778 */ 4779 SQLITE_API void *sqlite3_update_hook( 4780 sqlite3*, 4781 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4782 void* 4783 ); 4784 4785 /* 4786 ** CAPI3REF: Enable Or Disable Shared Pager Cache 4787 ** 4788 ** ^(This routine enables or disables the sharing of the database cache 4789 ** and schema data structures between [database connection | connections] 4790 ** to the same database. Sharing is enabled if the argument is true 4791 ** and disabled if the argument is false.)^ 4792 ** 4793 ** ^Cache sharing is enabled and disabled for an entire process. 4794 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4795 ** sharing was enabled or disabled for each thread separately. 4796 ** 4797 ** ^(The cache sharing mode set by this interface effects all subsequent 4798 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4799 ** Existing database connections continue use the sharing mode 4800 ** that was in effect at the time they were opened.)^ 4801 ** 4802 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4803 ** successfully. An [error code] is returned otherwise.)^ 4804 ** 4805 ** ^Shared cache is disabled by default. But this might change in 4806 ** future releases of SQLite. Applications that care about shared 4807 ** cache setting should set it explicitly. 4808 ** 4809 ** This interface is threadsafe on processors where writing a 4810 ** 32-bit integer is atomic. 4811 ** 4812 ** See Also: [SQLite Shared-Cache Mode] 4813 */ 4814 SQLITE_API int sqlite3_enable_shared_cache(int); 4815 4816 /* 4817 ** CAPI3REF: Attempt To Free Heap Memory 4818 ** 4819 ** ^The sqlite3_release_memory() interface attempts to free N bytes 4820 ** of heap memory by deallocating non-essential memory allocations 4821 ** held by the database library. Memory used to cache database 4822 ** pages to improve performance is an example of non-essential memory. 4823 ** ^sqlite3_release_memory() returns the number of bytes actually freed, 4824 ** which might be more or less than the amount requested. 4825 ** ^The sqlite3_release_memory() routine is a no-op returning zero 4826 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4827 ** 4828 ** See also: [sqlite3_db_release_memory()] 4829 */ 4830 SQLITE_API int sqlite3_release_memory(int); 4831 4832 /* 4833 ** CAPI3REF: Free Memory Used By A Database Connection 4834 ** 4835 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 4836 ** memory as possible from database connection D. Unlike the 4837 ** [sqlite3_release_memory()] interface, this interface is effect even 4838 ** when then [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 4839 ** omitted. 4840 ** 4841 ** See also: [sqlite3_release_memory()] 4842 */ 4843 SQLITE_API int sqlite3_db_release_memory(sqlite3*); 4844 4845 /* 4846 ** CAPI3REF: Impose A Limit On Heap Size 4847 ** 4848 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 4849 ** soft limit on the amount of heap memory that may be allocated by SQLite. 4850 ** ^SQLite strives to keep heap memory utilization below the soft heap 4851 ** limit by reducing the number of pages held in the page cache 4852 ** as heap memory usages approaches the limit. 4853 ** ^The soft heap limit is "soft" because even though SQLite strives to stay 4854 ** below the limit, it will exceed the limit rather than generate 4855 ** an [SQLITE_NOMEM] error. In other words, the soft heap limit 4856 ** is advisory only. 4857 ** 4858 ** ^The return value from sqlite3_soft_heap_limit64() is the size of 4859 ** the soft heap limit prior to the call, or negative in the case of an 4860 ** error. ^If the argument N is negative 4861 ** then no change is made to the soft heap limit. Hence, the current 4862 ** size of the soft heap limit can be determined by invoking 4863 ** sqlite3_soft_heap_limit64() with a negative argument. 4864 ** 4865 ** ^If the argument N is zero then the soft heap limit is disabled. 4866 ** 4867 ** ^(The soft heap limit is not enforced in the current implementation 4868 ** if one or more of following conditions are true: 4869 ** 4870 ** <ul> 4871 ** <li> The soft heap limit is set to zero. 4872 ** <li> Memory accounting is disabled using a combination of the 4873 ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 4874 ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 4875 ** <li> An alternative page cache implementation is specified using 4876 ** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 4877 ** <li> The page cache allocates from its own memory pool supplied 4878 ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 4879 ** from the heap. 4880 ** </ul>)^ 4881 ** 4882 ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 4883 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 4884 ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 4885 ** the soft heap limit is enforced on every memory allocation. Without 4886 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 4887 ** when memory is allocated by the page cache. Testing suggests that because 4888 ** the page cache is the predominate memory user in SQLite, most 4889 ** applications will achieve adequate soft heap limit enforcement without 4890 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4891 ** 4892 ** The circumstances under which SQLite will enforce the soft heap limit may 4893 ** changes in future releases of SQLite. 4894 */ 4895 SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 4896 4897 /* 4898 ** CAPI3REF: Deprecated Soft Heap Limit Interface 4899 ** DEPRECATED 4900 ** 4901 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 4902 ** interface. This routine is provided for historical compatibility 4903 ** only. All new applications should use the 4904 ** [sqlite3_soft_heap_limit64()] interface rather than this one. 4905 */ 4906 SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 4907 4908 4909 /* 4910 ** CAPI3REF: Extract Metadata About A Column Of A Table 4911 ** 4912 ** ^This routine returns metadata about a specific column of a specific 4913 ** database table accessible using the [database connection] handle 4914 ** passed as the first function argument. 4915 ** 4916 ** ^The column is identified by the second, third and fourth parameters to 4917 ** this function. ^The second parameter is either the name of the database 4918 ** (i.e. "main", "temp", or an attached database) containing the specified 4919 ** table or NULL. ^If it is NULL, then all attached databases are searched 4920 ** for the table using the same algorithm used by the database engine to 4921 ** resolve unqualified table references. 4922 ** 4923 ** ^The third and fourth parameters to this function are the table and column 4924 ** name of the desired column, respectively. Neither of these parameters 4925 ** may be NULL. 4926 ** 4927 ** ^Metadata is returned by writing to the memory locations passed as the 5th 4928 ** and subsequent parameters to this function. ^Any of these arguments may be 4929 ** NULL, in which case the corresponding element of metadata is omitted. 4930 ** 4931 ** ^(<blockquote> 4932 ** <table border="1"> 4933 ** <tr><th> Parameter <th> Output<br>Type <th> Description 4934 ** 4935 ** <tr><td> 5th <td> const char* <td> Data type 4936 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4937 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4938 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4939 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4940 ** </table> 4941 ** </blockquote>)^ 4942 ** 4943 ** ^The memory pointed to by the character pointers returned for the 4944 ** declaration type and collation sequence is valid only until the next 4945 ** call to any SQLite API function. 4946 ** 4947 ** ^If the specified table is actually a view, an [error code] is returned. 4948 ** 4949 ** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4950 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4951 ** parameters are set for the explicitly declared column. ^(If there is no 4952 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4953 ** parameters are set as follows: 4954 ** 4955 ** <pre> 4956 ** data type: "INTEGER" 4957 ** collation sequence: "BINARY" 4958 ** not null: 0 4959 ** primary key: 1 4960 ** auto increment: 0 4961 ** </pre>)^ 4962 ** 4963 ** ^(This function may load one or more schemas from database files. If an 4964 ** error occurs during this process, or if the requested table or column 4965 ** cannot be found, an [error code] is returned and an error message left 4966 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4967 ** 4968 ** ^This API is only available if the library was compiled with the 4969 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4970 */ 4971 SQLITE_API int sqlite3_table_column_metadata( 4972 sqlite3 *db, /* Connection handle */ 4973 const char *zDbName, /* Database name or NULL */ 4974 const char *zTableName, /* Table name */ 4975 const char *zColumnName, /* Column name */ 4976 char const **pzDataType, /* OUTPUT: Declared data type */ 4977 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4978 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4979 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4980 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4981 ); 4982 4983 /* 4984 ** CAPI3REF: Load An Extension 4985 ** 4986 ** ^This interface loads an SQLite extension library from the named file. 4987 ** 4988 ** ^The sqlite3_load_extension() interface attempts to load an 4989 ** SQLite extension library contained in the file zFile. 4990 ** 4991 ** ^The entry point is zProc. 4992 ** ^zProc may be 0, in which case the name of the entry point 4993 ** defaults to "sqlite3_extension_init". 4994 ** ^The sqlite3_load_extension() interface returns 4995 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4996 ** ^If an error occurs and pzErrMsg is not 0, then the 4997 ** [sqlite3_load_extension()] interface shall attempt to 4998 ** fill *pzErrMsg with error message text stored in memory 4999 ** obtained from [sqlite3_malloc()]. The calling function 5000 ** should free this memory by calling [sqlite3_free()]. 5001 ** 5002 ** ^Extension loading must be enabled using 5003 ** [sqlite3_enable_load_extension()] prior to calling this API, 5004 ** otherwise an error will be returned. 5005 ** 5006 ** See also the [load_extension() SQL function]. 5007 */ 5008 SQLITE_API int sqlite3_load_extension( 5009 sqlite3 *db, /* Load the extension into this database connection */ 5010 const char *zFile, /* Name of the shared library containing extension */ 5011 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5012 char **pzErrMsg /* Put error message here if not 0 */ 5013 ); 5014 5015 /* 5016 ** CAPI3REF: Enable Or Disable Extension Loading 5017 ** 5018 ** ^So as not to open security holes in older applications that are 5019 ** unprepared to deal with extension loading, and as a means of disabling 5020 ** extension loading while evaluating user-entered SQL, the following API 5021 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5022 ** 5023 ** ^Extension loading is off by default. See ticket #1863. 5024 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5025 ** to turn extension loading on and call it with onoff==0 to turn 5026 ** it back off again. 5027 */ 5028 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5029 5030 /* 5031 ** CAPI3REF: Automatically Load Statically Linked Extensions 5032 ** 5033 ** ^This interface causes the xEntryPoint() function to be invoked for 5034 ** each new [database connection] that is created. The idea here is that 5035 ** xEntryPoint() is the entry point for a statically linked SQLite extension 5036 ** that is to be automatically loaded into all new database connections. 5037 ** 5038 ** ^(Even though the function prototype shows that xEntryPoint() takes 5039 ** no arguments and returns void, SQLite invokes xEntryPoint() with three 5040 ** arguments and expects and integer result as if the signature of the 5041 ** entry point where as follows: 5042 ** 5043 ** <blockquote><pre> 5044 ** int xEntryPoint( 5045 ** sqlite3 *db, 5046 ** const char **pzErrMsg, 5047 ** const struct sqlite3_api_routines *pThunk 5048 ** ); 5049 ** </pre></blockquote>)^ 5050 ** 5051 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5052 ** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5053 ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5054 ** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5055 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5056 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5057 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 5058 ** 5059 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 5060 ** on the list of automatic extensions is a harmless no-op. ^No entry point 5061 ** will be called more than once for each database connection that is opened. 5062 ** 5063 ** See also: [sqlite3_reset_auto_extension()]. 5064 */ 5065 SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void)); 5066 5067 /* 5068 ** CAPI3REF: Reset Automatic Extension Loading 5069 ** 5070 ** ^This interface disables all automatic extensions previously 5071 ** registered using [sqlite3_auto_extension()]. 5072 */ 5073 SQLITE_API void sqlite3_reset_auto_extension(void); 5074 5075 /* 5076 ** The interface to the virtual-table mechanism is currently considered 5077 ** to be experimental. The interface might change in incompatible ways. 5078 ** If this is a problem for you, do not use the interface at this time. 5079 ** 5080 ** When the virtual-table mechanism stabilizes, we will declare the 5081 ** interface fixed, support it indefinitely, and remove this comment. 5082 */ 5083 5084 /* 5085 ** Structures used by the virtual table interface 5086 */ 5087 typedef struct sqlite3_vtab sqlite3_vtab; 5088 typedef struct sqlite3_index_info sqlite3_index_info; 5089 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 5090 typedef struct sqlite3_module sqlite3_module; 5091 5092 /* 5093 ** CAPI3REF: Virtual Table Object 5094 ** KEYWORDS: sqlite3_module {virtual table module} 5095 ** 5096 ** This structure, sometimes called a "virtual table module", 5097 ** defines the implementation of a [virtual tables]. 5098 ** This structure consists mostly of methods for the module. 5099 ** 5100 ** ^A virtual table module is created by filling in a persistent 5101 ** instance of this structure and passing a pointer to that instance 5102 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 5103 ** ^The registration remains valid until it is replaced by a different 5104 ** module or until the [database connection] closes. The content 5105 ** of this structure must not change while it is registered with 5106 ** any database connection. 5107 */ 5108 struct sqlite3_module { 5109 int iVersion; 5110 int (*xCreate)(sqlite3*, void *pAux, 5111 int argc, const char *const*argv, 5112 sqlite3_vtab **ppVTab, char**); 5113 int (*xConnect)(sqlite3*, void *pAux, 5114 int argc, const char *const*argv, 5115 sqlite3_vtab **ppVTab, char**); 5116 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 5117 int (*xDisconnect)(sqlite3_vtab *pVTab); 5118 int (*xDestroy)(sqlite3_vtab *pVTab); 5119 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 5120 int (*xClose)(sqlite3_vtab_cursor*); 5121 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 5122 int argc, sqlite3_value **argv); 5123 int (*xNext)(sqlite3_vtab_cursor*); 5124 int (*xEof)(sqlite3_vtab_cursor*); 5125 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 5126 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 5127 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 5128 int (*xBegin)(sqlite3_vtab *pVTab); 5129 int (*xSync)(sqlite3_vtab *pVTab); 5130 int (*xCommit)(sqlite3_vtab *pVTab); 5131 int (*xRollback)(sqlite3_vtab *pVTab); 5132 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 5133 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 5134 void **ppArg); 5135 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 5136 /* The methods above are in version 1 of the sqlite_module object. Those 5137 ** below are for version 2 and greater. */ 5138 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 5139 int (*xRelease)(sqlite3_vtab *pVTab, int); 5140 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 5141 }; 5142 5143 /* 5144 ** CAPI3REF: Virtual Table Indexing Information 5145 ** KEYWORDS: sqlite3_index_info 5146 ** 5147 ** The sqlite3_index_info structure and its substructures is used as part 5148 ** of the [virtual table] interface to 5149 ** pass information into and receive the reply from the [xBestIndex] 5150 ** method of a [virtual table module]. The fields under **Inputs** are the 5151 ** inputs to xBestIndex and are read-only. xBestIndex inserts its 5152 ** results into the **Outputs** fields. 5153 ** 5154 ** ^(The aConstraint[] array records WHERE clause constraints of the form: 5155 ** 5156 ** <blockquote>column OP expr</blockquote> 5157 ** 5158 ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 5159 ** stored in aConstraint[].op using one of the 5160 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 5161 ** ^(The index of the column is stored in 5162 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5163 ** expr on the right-hand side can be evaluated (and thus the constraint 5164 ** is usable) and false if it cannot.)^ 5165 ** 5166 ** ^The optimizer automatically inverts terms of the form "expr OP column" 5167 ** and makes other simplifications to the WHERE clause in an attempt to 5168 ** get as many WHERE clause terms into the form shown above as possible. 5169 ** ^The aConstraint[] array only reports WHERE clause terms that are 5170 ** relevant to the particular virtual table being queried. 5171 ** 5172 ** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5173 ** ^Each term of aOrderBy records a column of the ORDER BY clause. 5174 ** 5175 ** The [xBestIndex] method must fill aConstraintUsage[] with information 5176 ** about what parameters to pass to xFilter. ^If argvIndex>0 then 5177 ** the right-hand side of the corresponding aConstraint[] is evaluated 5178 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5179 ** is true, then the constraint is assumed to be fully handled by the 5180 ** virtual table and is not checked again by SQLite.)^ 5181 ** 5182 ** ^The idxNum and idxPtr values are recorded and passed into the 5183 ** [xFilter] method. 5184 ** ^[sqlite3_free()] is used to free idxPtr if and only if 5185 ** needToFreeIdxPtr is true. 5186 ** 5187 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5188 ** the correct order to satisfy the ORDER BY clause so that no separate 5189 ** sorting step is required. 5190 ** 5191 ** ^The estimatedCost value is an estimate of the cost of doing the 5192 ** particular lookup. A full scan of a table with N entries should have 5193 ** a cost of N. A binary search of a table of N entries should have a 5194 ** cost of approximately log(N). 5195 */ 5196 struct sqlite3_index_info { 5197 /* Inputs */ 5198 int nConstraint; /* Number of entries in aConstraint */ 5199 struct sqlite3_index_constraint { 5200 int iColumn; /* Column on left-hand side of constraint */ 5201 unsigned char op; /* Constraint operator */ 5202 unsigned char usable; /* True if this constraint is usable */ 5203 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5204 } *aConstraint; /* Table of WHERE clause constraints */ 5205 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5206 struct sqlite3_index_orderby { 5207 int iColumn; /* Column number */ 5208 unsigned char desc; /* True for DESC. False for ASC. */ 5209 } *aOrderBy; /* The ORDER BY clause */ 5210 /* Outputs */ 5211 struct sqlite3_index_constraint_usage { 5212 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5213 unsigned char omit; /* Do not code a test for this constraint */ 5214 } *aConstraintUsage; 5215 int idxNum; /* Number used to identify the index */ 5216 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5217 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5218 int orderByConsumed; /* True if output is already ordered */ 5219 double estimatedCost; /* Estimated cost of using this index */ 5220 }; 5221 5222 /* 5223 ** CAPI3REF: Virtual Table Constraint Operator Codes 5224 ** 5225 ** These macros defined the allowed values for the 5226 ** [sqlite3_index_info].aConstraint[].op field. Each value represents 5227 ** an operator that is part of a constraint term in the wHERE clause of 5228 ** a query that uses a [virtual table]. 5229 */ 5230 #define SQLITE_INDEX_CONSTRAINT_EQ 2 5231 #define SQLITE_INDEX_CONSTRAINT_GT 4 5232 #define SQLITE_INDEX_CONSTRAINT_LE 8 5233 #define SQLITE_INDEX_CONSTRAINT_LT 16 5234 #define SQLITE_INDEX_CONSTRAINT_GE 32 5235 #define SQLITE_INDEX_CONSTRAINT_MATCH 64 5236 5237 /* 5238 ** CAPI3REF: Register A Virtual Table Implementation 5239 ** 5240 ** ^These routines are used to register a new [virtual table module] name. 5241 ** ^Module names must be registered before 5242 ** creating a new [virtual table] using the module and before using a 5243 ** preexisting [virtual table] for the module. 5244 ** 5245 ** ^The module name is registered on the [database connection] specified 5246 ** by the first parameter. ^The name of the module is given by the 5247 ** second parameter. ^The third parameter is a pointer to 5248 ** the implementation of the [virtual table module]. ^The fourth 5249 ** parameter is an arbitrary client data pointer that is passed through 5250 ** into the [xCreate] and [xConnect] methods of the virtual table module 5251 ** when a new virtual table is be being created or reinitialized. 5252 ** 5253 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which 5254 ** is a pointer to a destructor for the pClientData. ^SQLite will 5255 ** invoke the destructor function (if it is not NULL) when SQLite 5256 ** no longer needs the pClientData pointer. ^The destructor will also 5257 ** be invoked if the call to sqlite3_create_module_v2() fails. 5258 ** ^The sqlite3_create_module() 5259 ** interface is equivalent to sqlite3_create_module_v2() with a NULL 5260 ** destructor. 5261 */ 5262 SQLITE_API int sqlite3_create_module( 5263 sqlite3 *db, /* SQLite connection to register module with */ 5264 const char *zName, /* Name of the module */ 5265 const sqlite3_module *p, /* Methods for the module */ 5266 void *pClientData /* Client data for xCreate/xConnect */ 5267 ); 5268 SQLITE_API int sqlite3_create_module_v2( 5269 sqlite3 *db, /* SQLite connection to register module with */ 5270 const char *zName, /* Name of the module */ 5271 const sqlite3_module *p, /* Methods for the module */ 5272 void *pClientData, /* Client data for xCreate/xConnect */ 5273 void(*xDestroy)(void*) /* Module destructor function */ 5274 ); 5275 5276 /* 5277 ** CAPI3REF: Virtual Table Instance Object 5278 ** KEYWORDS: sqlite3_vtab 5279 ** 5280 ** Every [virtual table module] implementation uses a subclass 5281 ** of this object to describe a particular instance 5282 ** of the [virtual table]. Each subclass will 5283 ** be tailored to the specific needs of the module implementation. 5284 ** The purpose of this superclass is to define certain fields that are 5285 ** common to all module implementations. 5286 ** 5287 ** ^Virtual tables methods can set an error message by assigning a 5288 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 5289 ** take care that any prior string is freed by a call to [sqlite3_free()] 5290 ** prior to assigning a new string to zErrMsg. ^After the error message 5291 ** is delivered up to the client application, the string will be automatically 5292 ** freed by sqlite3_free() and the zErrMsg field will be zeroed. 5293 */ 5294 struct sqlite3_vtab { 5295 const sqlite3_module *pModule; /* The module for this virtual table */ 5296 int nRef; /* NO LONGER USED */ 5297 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 5298 /* Virtual table implementations will typically add additional fields */ 5299 }; 5300 5301 /* 5302 ** CAPI3REF: Virtual Table Cursor Object 5303 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 5304 ** 5305 ** Every [virtual table module] implementation uses a subclass of the 5306 ** following structure to describe cursors that point into the 5307 ** [virtual table] and are used 5308 ** to loop through the virtual table. Cursors are created using the 5309 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 5310 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used 5311 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 5312 ** of the module. Each module implementation will define 5313 ** the content of a cursor structure to suit its own needs. 5314 ** 5315 ** This superclass exists in order to define fields of the cursor that 5316 ** are common to all implementations. 5317 */ 5318 struct sqlite3_vtab_cursor { 5319 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 5320 /* Virtual table implementations will typically add additional fields */ 5321 }; 5322 5323 /* 5324 ** CAPI3REF: Declare The Schema Of A Virtual Table 5325 ** 5326 ** ^The [xCreate] and [xConnect] methods of a 5327 ** [virtual table module] call this interface 5328 ** to declare the format (the names and datatypes of the columns) of 5329 ** the virtual tables they implement. 5330 */ 5331 SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 5332 5333 /* 5334 ** CAPI3REF: Overload A Function For A Virtual Table 5335 ** 5336 ** ^(Virtual tables can provide alternative implementations of functions 5337 ** using the [xFindFunction] method of the [virtual table module]. 5338 ** But global versions of those functions 5339 ** must exist in order to be overloaded.)^ 5340 ** 5341 ** ^(This API makes sure a global version of a function with a particular 5342 ** name and number of parameters exists. If no such function exists 5343 ** before this API is called, a new function is created.)^ ^The implementation 5344 ** of the new function always causes an exception to be thrown. So 5345 ** the new function is not good for anything by itself. Its only 5346 ** purpose is to be a placeholder function that can be overloaded 5347 ** by a [virtual table]. 5348 */ 5349 SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5350 5351 /* 5352 ** The interface to the virtual-table mechanism defined above (back up 5353 ** to a comment remarkably similar to this one) is currently considered 5354 ** to be experimental. The interface might change in incompatible ways. 5355 ** If this is a problem for you, do not use the interface at this time. 5356 ** 5357 ** When the virtual-table mechanism stabilizes, we will declare the 5358 ** interface fixed, support it indefinitely, and remove this comment. 5359 */ 5360 5361 /* 5362 ** CAPI3REF: A Handle To An Open BLOB 5363 ** KEYWORDS: {BLOB handle} {BLOB handles} 5364 ** 5365 ** An instance of this object represents an open BLOB on which 5366 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5367 ** ^Objects of this type are created by [sqlite3_blob_open()] 5368 ** and destroyed by [sqlite3_blob_close()]. 5369 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5370 ** can be used to read or write small subsections of the BLOB. 5371 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5372 */ 5373 typedef struct sqlite3_blob sqlite3_blob; 5374 5375 /* 5376 ** CAPI3REF: Open A BLOB For Incremental I/O 5377 ** 5378 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5379 ** in row iRow, column zColumn, table zTable in database zDb; 5380 ** in other words, the same BLOB that would be selected by: 5381 ** 5382 ** <pre> 5383 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5384 ** </pre>)^ 5385 ** 5386 ** ^If the flags parameter is non-zero, then the BLOB is opened for read 5387 ** and write access. ^If it is zero, the BLOB is opened for read access. 5388 ** ^It is not possible to open a column that is part of an index or primary 5389 ** key for writing. ^If [foreign key constraints] are enabled, it is 5390 ** not possible to open a column that is part of a [child key] for writing. 5391 ** 5392 ** ^Note that the database name is not the filename that contains 5393 ** the database but rather the symbolic name of the database that 5394 ** appears after the AS keyword when the database is connected using [ATTACH]. 5395 ** ^For the main database file, the database name is "main". 5396 ** ^For TEMP tables, the database name is "temp". 5397 ** 5398 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 5399 ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 5400 ** to be a null pointer.)^ 5401 ** ^This function sets the [database connection] error code and message 5402 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 5403 ** functions. ^Note that the *ppBlob variable is always initialized in a 5404 ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 5405 ** regardless of the success or failure of this routine. 5406 ** 5407 ** ^(If the row that a BLOB handle points to is modified by an 5408 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5409 ** then the BLOB handle is marked as "expired". 5410 ** This is true if any column of the row is changed, even a column 5411 ** other than the one the BLOB handle is open on.)^ 5412 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5413 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5414 ** ^(Changes written into a BLOB prior to the BLOB expiring are not 5415 ** rolled back by the expiration of the BLOB. Such changes will eventually 5416 ** commit if the transaction continues to completion.)^ 5417 ** 5418 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5419 ** the opened blob. ^The size of a blob may not be changed by this 5420 ** interface. Use the [UPDATE] SQL command to change the size of a 5421 ** blob. 5422 ** 5423 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5424 ** and the built-in [zeroblob] SQL function can be used, if desired, 5425 ** to create an empty, zero-filled blob in which to read or write using 5426 ** this interface. 5427 ** 5428 ** To avoid a resource leak, every open [BLOB handle] should eventually 5429 ** be released by a call to [sqlite3_blob_close()]. 5430 */ 5431 SQLITE_API int sqlite3_blob_open( 5432 sqlite3*, 5433 const char *zDb, 5434 const char *zTable, 5435 const char *zColumn, 5436 sqlite3_int64 iRow, 5437 int flags, 5438 sqlite3_blob **ppBlob 5439 ); 5440 5441 /* 5442 ** CAPI3REF: Move a BLOB Handle to a New Row 5443 ** 5444 ** ^This function is used to move an existing blob handle so that it points 5445 ** to a different row of the same database table. ^The new row is identified 5446 ** by the rowid value passed as the second argument. Only the row can be 5447 ** changed. ^The database, table and column on which the blob handle is open 5448 ** remain the same. Moving an existing blob handle to a new row can be 5449 ** faster than closing the existing handle and opening a new one. 5450 ** 5451 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5452 ** it must exist and there must be either a blob or text value stored in 5453 ** the nominated column.)^ ^If the new row is not present in the table, or if 5454 ** it does not contain a blob or text value, or if another error occurs, an 5455 ** SQLite error code is returned and the blob handle is considered aborted. 5456 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5457 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5458 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5459 ** always returns zero. 5460 ** 5461 ** ^This function sets the database handle error code and message. 5462 */ 5463 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5464 5465 /* 5466 ** CAPI3REF: Close A BLOB Handle 5467 ** 5468 ** ^Closes an open [BLOB handle]. 5469 ** 5470 ** ^Closing a BLOB shall cause the current transaction to commit 5471 ** if there are no other BLOBs, no pending prepared statements, and the 5472 ** database connection is in [autocommit mode]. 5473 ** ^If any writes were made to the BLOB, they might be held in cache 5474 ** until the close operation if they will fit. 5475 ** 5476 ** ^(Closing the BLOB often forces the changes 5477 ** out to disk and so if any I/O errors occur, they will likely occur 5478 ** at the time when the BLOB is closed. Any errors that occur during 5479 ** closing are reported as a non-zero return value.)^ 5480 ** 5481 ** ^(The BLOB is closed unconditionally. Even if this routine returns 5482 ** an error code, the BLOB is still closed.)^ 5483 ** 5484 ** ^Calling this routine with a null pointer (such as would be returned 5485 ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 5486 */ 5487 SQLITE_API int sqlite3_blob_close(sqlite3_blob *); 5488 5489 /* 5490 ** CAPI3REF: Return The Size Of An Open BLOB 5491 ** 5492 ** ^Returns the size in bytes of the BLOB accessible via the 5493 ** successfully opened [BLOB handle] in its only argument. ^The 5494 ** incremental blob I/O routines can only read or overwriting existing 5495 ** blob content; they cannot change the size of a blob. 5496 ** 5497 ** This routine only works on a [BLOB handle] which has been created 5498 ** by a prior successful call to [sqlite3_blob_open()] and which has not 5499 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5500 ** to this routine results in undefined and probably undesirable behavior. 5501 */ 5502 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *); 5503 5504 /* 5505 ** CAPI3REF: Read Data From A BLOB Incrementally 5506 ** 5507 ** ^(This function is used to read data from an open [BLOB handle] into a 5508 ** caller-supplied buffer. N bytes of data are copied into buffer Z 5509 ** from the open BLOB, starting at offset iOffset.)^ 5510 ** 5511 ** ^If offset iOffset is less than N bytes from the end of the BLOB, 5512 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 5513 ** less than zero, [SQLITE_ERROR] is returned and no data is read. 5514 ** ^The size of the blob (and hence the maximum value of N+iOffset) 5515 ** can be determined using the [sqlite3_blob_bytes()] interface. 5516 ** 5517 ** ^An attempt to read from an expired [BLOB handle] fails with an 5518 ** error code of [SQLITE_ABORT]. 5519 ** 5520 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 5521 ** Otherwise, an [error code] or an [extended error code] is returned.)^ 5522 ** 5523 ** This routine only works on a [BLOB handle] which has been created 5524 ** by a prior successful call to [sqlite3_blob_open()] and which has not 5525 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5526 ** to this routine results in undefined and probably undesirable behavior. 5527 ** 5528 ** See also: [sqlite3_blob_write()]. 5529 */ 5530 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 5531 5532 /* 5533 ** CAPI3REF: Write Data Into A BLOB Incrementally 5534 ** 5535 ** ^This function is used to write data into an open [BLOB handle] from a 5536 ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 5537 ** into the open BLOB, starting at offset iOffset. 5538 ** 5539 ** ^If the [BLOB handle] passed as the first argument was not opened for 5540 ** writing (the flags parameter to [sqlite3_blob_open()] was zero), 5541 ** this function returns [SQLITE_READONLY]. 5542 ** 5543 ** ^This function may only modify the contents of the BLOB; it is 5544 ** not possible to increase the size of a BLOB using this API. 5545 ** ^If offset iOffset is less than N bytes from the end of the BLOB, 5546 ** [SQLITE_ERROR] is returned and no data is written. ^If N is 5547 ** less than zero [SQLITE_ERROR] is returned and no data is written. 5548 ** The size of the BLOB (and hence the maximum value of N+iOffset) 5549 ** can be determined using the [sqlite3_blob_bytes()] interface. 5550 ** 5551 ** ^An attempt to write to an expired [BLOB handle] fails with an 5552 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 5553 ** before the [BLOB handle] expired are not rolled back by the 5554 ** expiration of the handle, though of course those changes might 5555 ** have been overwritten by the statement that expired the BLOB handle 5556 ** or by other independent statements. 5557 ** 5558 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 5559 ** Otherwise, an [error code] or an [extended error code] is returned.)^ 5560 ** 5561 ** This routine only works on a [BLOB handle] which has been created 5562 ** by a prior successful call to [sqlite3_blob_open()] and which has not 5563 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5564 ** to this routine results in undefined and probably undesirable behavior. 5565 ** 5566 ** See also: [sqlite3_blob_read()]. 5567 */ 5568 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 5569 5570 /* 5571 ** CAPI3REF: Virtual File System Objects 5572 ** 5573 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object 5574 ** that SQLite uses to interact 5575 ** with the underlying operating system. Most SQLite builds come with a 5576 ** single default VFS that is appropriate for the host computer. 5577 ** New VFSes can be registered and existing VFSes can be unregistered. 5578 ** The following interfaces are provided. 5579 ** 5580 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 5581 ** ^Names are case sensitive. 5582 ** ^Names are zero-terminated UTF-8 strings. 5583 ** ^If there is no match, a NULL pointer is returned. 5584 ** ^If zVfsName is NULL then the default VFS is returned. 5585 ** 5586 ** ^New VFSes are registered with sqlite3_vfs_register(). 5587 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 5588 ** ^The same VFS can be registered multiple times without injury. 5589 ** ^To make an existing VFS into the default VFS, register it again 5590 ** with the makeDflt flag set. If two different VFSes with the 5591 ** same name are registered, the behavior is undefined. If a 5592 ** VFS is registered with a name that is NULL or an empty string, 5593 ** then the behavior is undefined. 5594 ** 5595 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 5596 ** ^(If the default VFS is unregistered, another VFS is chosen as 5597 ** the default. The choice for the new VFS is arbitrary.)^ 5598 */ 5599 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 5600 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 5601 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*); 5602 5603 /* 5604 ** CAPI3REF: Mutexes 5605 ** 5606 ** The SQLite core uses these routines for thread 5607 ** synchronization. Though they are intended for internal 5608 ** use by SQLite, code that links against SQLite is 5609 ** permitted to use any of these routines. 5610 ** 5611 ** The SQLite source code contains multiple implementations 5612 ** of these mutex routines. An appropriate implementation 5613 ** is selected automatically at compile-time. ^(The following 5614 ** implementations are available in the SQLite core: 5615 ** 5616 ** <ul> 5617 ** <li> SQLITE_MUTEX_PTHREADS 5618 ** <li> SQLITE_MUTEX_W32 5619 ** <li> SQLITE_MUTEX_NOOP 5620 ** </ul>)^ 5621 ** 5622 ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 5623 ** that does no real locking and is appropriate for use in 5624 ** a single-threaded application. ^The SQLITE_MUTEX_PTHREADS and 5625 ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 5626 ** and Windows. 5627 ** 5628 ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 5629 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 5630 ** implementation is included with the library. In this case the 5631 ** application must supply a custom mutex implementation using the 5632 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 5633 ** before calling sqlite3_initialize() or any other public sqlite3_ 5634 ** function that calls sqlite3_initialize().)^ 5635 ** 5636 ** ^The sqlite3_mutex_alloc() routine allocates a new 5637 ** mutex and returns a pointer to it. ^If it returns NULL 5638 ** that means that a mutex could not be allocated. ^SQLite 5639 ** will unwind its stack and return an error. ^(The argument 5640 ** to sqlite3_mutex_alloc() is one of these integer constants: 5641 ** 5642 ** <ul> 5643 ** <li> SQLITE_MUTEX_FAST 5644 ** <li> SQLITE_MUTEX_RECURSIVE 5645 ** <li> SQLITE_MUTEX_STATIC_MASTER 5646 ** <li> SQLITE_MUTEX_STATIC_MEM 5647 ** <li> SQLITE_MUTEX_STATIC_MEM2 5648 ** <li> SQLITE_MUTEX_STATIC_PRNG 5649 ** <li> SQLITE_MUTEX_STATIC_LRU 5650 ** <li> SQLITE_MUTEX_STATIC_LRU2 5651 ** </ul>)^ 5652 ** 5653 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 5654 ** cause sqlite3_mutex_alloc() to create 5655 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 5656 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 5657 ** The mutex implementation does not need to make a distinction 5658 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 5659 ** not want to. ^SQLite will only request a recursive mutex in 5660 ** cases where it really needs one. ^If a faster non-recursive mutex 5661 ** implementation is available on the host platform, the mutex subsystem 5662 ** might return such a mutex in response to SQLITE_MUTEX_FAST. 5663 ** 5664 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 5665 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 5666 ** a pointer to a static preexisting mutex. ^Six static mutexes are 5667 ** used by the current version of SQLite. Future versions of SQLite 5668 ** may add additional static mutexes. Static mutexes are for internal 5669 ** use by SQLite only. Applications that use SQLite mutexes should 5670 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 5671 ** SQLITE_MUTEX_RECURSIVE. 5672 ** 5673 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 5674 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 5675 ** returns a different mutex on every call. ^But for the static 5676 ** mutex types, the same mutex is returned on every call that has 5677 ** the same type number. 5678 ** 5679 ** ^The sqlite3_mutex_free() routine deallocates a previously 5680 ** allocated dynamic mutex. ^SQLite is careful to deallocate every 5681 ** dynamic mutex that it allocates. The dynamic mutexes must not be in 5682 ** use when they are deallocated. Attempting to deallocate a static 5683 ** mutex results in undefined behavior. ^SQLite never deallocates 5684 ** a static mutex. 5685 ** 5686 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 5687 ** to enter a mutex. ^If another thread is already within the mutex, 5688 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 5689 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 5690 ** upon successful entry. ^(Mutexes created using 5691 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 5692 ** In such cases the, 5693 ** mutex must be exited an equal number of times before another thread 5694 ** can enter.)^ ^(If the same thread tries to enter any other 5695 ** kind of mutex more than once, the behavior is undefined. 5696 ** SQLite will never exhibit 5697 ** such behavior in its own use of mutexes.)^ 5698 ** 5699 ** ^(Some systems (for example, Windows 95) do not support the operation 5700 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 5701 ** will always return SQLITE_BUSY. The SQLite core only ever uses 5702 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 5703 ** 5704 ** ^The sqlite3_mutex_leave() routine exits a mutex that was 5705 ** previously entered by the same thread. ^(The behavior 5706 ** is undefined if the mutex is not currently entered by the 5707 ** calling thread or is not currently allocated. SQLite will 5708 ** never do either.)^ 5709 ** 5710 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 5711 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines 5712 ** behave as no-ops. 5713 ** 5714 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 5715 */ 5716 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int); 5717 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*); 5718 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*); 5719 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*); 5720 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*); 5721 5722 /* 5723 ** CAPI3REF: Mutex Methods Object 5724 ** 5725 ** An instance of this structure defines the low-level routines 5726 ** used to allocate and use mutexes. 5727 ** 5728 ** Usually, the default mutex implementations provided by SQLite are 5729 ** sufficient, however the user has the option of substituting a custom 5730 ** implementation for specialized deployments or systems for which SQLite 5731 ** does not provide a suitable implementation. In this case, the user 5732 ** creates and populates an instance of this structure to pass 5733 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 5734 ** Additionally, an instance of this structure can be used as an 5735 ** output variable when querying the system for the current mutex 5736 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 5737 ** 5738 ** ^The xMutexInit method defined by this structure is invoked as 5739 ** part of system initialization by the sqlite3_initialize() function. 5740 ** ^The xMutexInit routine is called by SQLite exactly once for each 5741 ** effective call to [sqlite3_initialize()]. 5742 ** 5743 ** ^The xMutexEnd method defined by this structure is invoked as 5744 ** part of system shutdown by the sqlite3_shutdown() function. The 5745 ** implementation of this method is expected to release all outstanding 5746 ** resources obtained by the mutex methods implementation, especially 5747 ** those obtained by the xMutexInit method. ^The xMutexEnd() 5748 ** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 5749 ** 5750 ** ^(The remaining seven methods defined by this structure (xMutexAlloc, 5751 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 5752 ** xMutexNotheld) implement the following interfaces (respectively): 5753 ** 5754 ** <ul> 5755 ** <li> [sqlite3_mutex_alloc()] </li> 5756 ** <li> [sqlite3_mutex_free()] </li> 5757 ** <li> [sqlite3_mutex_enter()] </li> 5758 ** <li> [sqlite3_mutex_try()] </li> 5759 ** <li> [sqlite3_mutex_leave()] </li> 5760 ** <li> [sqlite3_mutex_held()] </li> 5761 ** <li> [sqlite3_mutex_notheld()] </li> 5762 ** </ul>)^ 5763 ** 5764 ** The only difference is that the public sqlite3_XXX functions enumerated 5765 ** above silently ignore any invocations that pass a NULL pointer instead 5766 ** of a valid mutex handle. The implementations of the methods defined 5767 ** by this structure are not required to handle this case, the results 5768 ** of passing a NULL pointer instead of a valid mutex handle are undefined 5769 ** (i.e. it is acceptable to provide an implementation that segfaults if 5770 ** it is passed a NULL pointer). 5771 ** 5772 ** The xMutexInit() method must be threadsafe. ^It must be harmless to 5773 ** invoke xMutexInit() multiple times within the same process and without 5774 ** intervening calls to xMutexEnd(). Second and subsequent calls to 5775 ** xMutexInit() must be no-ops. 5776 ** 5777 ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 5778 ** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 5779 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 5780 ** memory allocation for a fast or recursive mutex. 5781 ** 5782 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 5783 ** called, but only if the prior call to xMutexInit returned SQLITE_OK. 5784 ** If xMutexInit fails in any way, it is expected to clean up after itself 5785 ** prior to returning. 5786 */ 5787 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 5788 struct sqlite3_mutex_methods { 5789 int (*xMutexInit)(void); 5790 int (*xMutexEnd)(void); 5791 sqlite3_mutex *(*xMutexAlloc)(int); 5792 void (*xMutexFree)(sqlite3_mutex *); 5793 void (*xMutexEnter)(sqlite3_mutex *); 5794 int (*xMutexTry)(sqlite3_mutex *); 5795 void (*xMutexLeave)(sqlite3_mutex *); 5796 int (*xMutexHeld)(sqlite3_mutex *); 5797 int (*xMutexNotheld)(sqlite3_mutex *); 5798 }; 5799 5800 /* 5801 ** CAPI3REF: Mutex Verification Routines 5802 ** 5803 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 5804 ** are intended for use inside assert() statements. ^The SQLite core 5805 ** never uses these routines except inside an assert() and applications 5806 ** are advised to follow the lead of the core. ^The SQLite core only 5807 ** provides implementations for these routines when it is compiled 5808 ** with the SQLITE_DEBUG flag. ^External mutex implementations 5809 ** are only required to provide these routines if SQLITE_DEBUG is 5810 ** defined and if NDEBUG is not defined. 5811 ** 5812 ** ^These routines should return true if the mutex in their argument 5813 ** is held or not held, respectively, by the calling thread. 5814 ** 5815 ** ^The implementation is not required to provide versions of these 5816 ** routines that actually work. If the implementation does not provide working 5817 ** versions of these routines, it should at least provide stubs that always 5818 ** return true so that one does not get spurious assertion failures. 5819 ** 5820 ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 5821 ** the routine should return 1. This seems counter-intuitive since 5822 ** clearly the mutex cannot be held if it does not exist. But 5823 ** the reason the mutex does not exist is because the build is not 5824 ** using mutexes. And we do not want the assert() containing the 5825 ** call to sqlite3_mutex_held() to fail, so a non-zero return is 5826 ** the appropriate thing to do. ^The sqlite3_mutex_notheld() 5827 ** interface should also return 1 when given a NULL pointer. 5828 */ 5829 #ifndef NDEBUG 5830 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*); 5831 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*); 5832 #endif 5833 5834 /* 5835 ** CAPI3REF: Mutex Types 5836 ** 5837 ** The [sqlite3_mutex_alloc()] interface takes a single argument 5838 ** which is one of these integer constants. 5839 ** 5840 ** The set of static mutexes may change from one SQLite release to the 5841 ** next. Applications that override the built-in mutex logic must be 5842 ** prepared to accommodate additional static mutexes. 5843 */ 5844 #define SQLITE_MUTEX_FAST 0 5845 #define SQLITE_MUTEX_RECURSIVE 1 5846 #define SQLITE_MUTEX_STATIC_MASTER 2 5847 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 5848 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 5849 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 5850 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 5851 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 5852 #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 5853 #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 5854 5855 /* 5856 ** CAPI3REF: Retrieve the mutex for a database connection 5857 ** 5858 ** ^This interface returns a pointer the [sqlite3_mutex] object that 5859 ** serializes access to the [database connection] given in the argument 5860 ** when the [threading mode] is Serialized. 5861 ** ^If the [threading mode] is Single-thread or Multi-thread then this 5862 ** routine returns a NULL pointer. 5863 */ 5864 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 5865 5866 /* 5867 ** CAPI3REF: Low-Level Control Of Database Files 5868 ** 5869 ** ^The [sqlite3_file_control()] interface makes a direct call to the 5870 ** xFileControl method for the [sqlite3_io_methods] object associated 5871 ** with a particular database identified by the second argument. ^The 5872 ** name of the database is "main" for the main database or "temp" for the 5873 ** TEMP database, or the name that appears after the AS keyword for 5874 ** databases that are added using the [ATTACH] SQL command. 5875 ** ^A NULL pointer can be used in place of "main" to refer to the 5876 ** main database file. 5877 ** ^The third and fourth parameters to this routine 5878 ** are passed directly through to the second and third parameters of 5879 ** the xFileControl method. ^The return value of the xFileControl 5880 ** method becomes the return value of this routine. 5881 ** 5882 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 5883 ** a pointer to the underlying [sqlite3_file] object to be written into 5884 ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 5885 ** case is a short-circuit path which does not actually invoke the 5886 ** underlying sqlite3_io_methods.xFileControl method. 5887 ** 5888 ** ^If the second parameter (zDbName) does not match the name of any 5889 ** open database file, then SQLITE_ERROR is returned. ^This error 5890 ** code is not remembered and will not be recalled by [sqlite3_errcode()] 5891 ** or [sqlite3_errmsg()]. The underlying xFileControl method might 5892 ** also return SQLITE_ERROR. There is no way to distinguish between 5893 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5894 ** xFileControl method. 5895 ** 5896 ** See also: [SQLITE_FCNTL_LOCKSTATE] 5897 */ 5898 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5899 5900 /* 5901 ** CAPI3REF: Testing Interface 5902 ** 5903 ** ^The sqlite3_test_control() interface is used to read out internal 5904 ** state of SQLite and to inject faults into SQLite for testing 5905 ** purposes. ^The first parameter is an operation code that determines 5906 ** the number, meaning, and operation of all subsequent parameters. 5907 ** 5908 ** This interface is not for use by applications. It exists solely 5909 ** for verifying the correct operation of the SQLite library. Depending 5910 ** on how the SQLite library is compiled, this interface might not exist. 5911 ** 5912 ** The details of the operation codes, their meanings, the parameters 5913 ** they take, and what they do are all subject to change without notice. 5914 ** Unlike most of the SQLite API, this function is not guaranteed to 5915 ** operate consistently from one release to the next. 5916 */ 5917 SQLITE_API int sqlite3_test_control(int op, ...); 5918 5919 /* 5920 ** CAPI3REF: Testing Interface Operation Codes 5921 ** 5922 ** These constants are the valid operation code parameters used 5923 ** as the first argument to [sqlite3_test_control()]. 5924 ** 5925 ** These parameters and their meanings are subject to change 5926 ** without notice. These values are for testing purposes only. 5927 ** Applications should not use any of these parameters or the 5928 ** [sqlite3_test_control()] interface. 5929 */ 5930 #define SQLITE_TESTCTRL_FIRST 5 5931 #define SQLITE_TESTCTRL_PRNG_SAVE 5 5932 #define SQLITE_TESTCTRL_PRNG_RESTORE 6 5933 #define SQLITE_TESTCTRL_PRNG_RESET 7 5934 #define SQLITE_TESTCTRL_BITVEC_TEST 8 5935 #define SQLITE_TESTCTRL_FAULT_INSTALL 9 5936 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5937 #define SQLITE_TESTCTRL_PENDING_BYTE 11 5938 #define SQLITE_TESTCTRL_ASSERT 12 5939 #define SQLITE_TESTCTRL_ALWAYS 13 5940 #define SQLITE_TESTCTRL_RESERVE 14 5941 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15 5942 #define SQLITE_TESTCTRL_ISKEYWORD 16 5943 #define SQLITE_TESTCTRL_SCRATCHMALLOC 17 5944 #define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 5945 #define SQLITE_TESTCTRL_EXPLAIN_STMT 19 5946 #define SQLITE_TESTCTRL_LAST 19 5947 5948 /* 5949 ** CAPI3REF: SQLite Runtime Status 5950 ** 5951 ** ^This interface is used to retrieve runtime status information 5952 ** about the performance of SQLite, and optionally to reset various 5953 ** highwater marks. ^The first argument is an integer code for 5954 ** the specific parameter to measure. ^(Recognized integer codes 5955 ** are of the form [status parameters | SQLITE_STATUS_...].)^ 5956 ** ^The current value of the parameter is returned into *pCurrent. 5957 ** ^The highest recorded value is returned in *pHighwater. ^If the 5958 ** resetFlag is true, then the highest record value is reset after 5959 ** *pHighwater is written. ^(Some parameters do not record the highest 5960 ** value. For those parameters 5961 ** nothing is written into *pHighwater and the resetFlag is ignored.)^ 5962 ** ^(Other parameters record only the highwater mark and not the current 5963 ** value. For these latter parameters nothing is written into *pCurrent.)^ 5964 ** 5965 ** ^The sqlite3_status() routine returns SQLITE_OK on success and a 5966 ** non-zero [error code] on failure. 5967 ** 5968 ** This routine is threadsafe but is not atomic. This routine can be 5969 ** called while other threads are running the same or different SQLite 5970 ** interfaces. However the values returned in *pCurrent and 5971 ** *pHighwater reflect the status of SQLite at different points in time 5972 ** and it is possible that another thread might change the parameter 5973 ** in between the times when *pCurrent and *pHighwater are written. 5974 ** 5975 ** See also: [sqlite3_db_status()] 5976 */ 5977 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 5978 5979 5980 /* 5981 ** CAPI3REF: Status Parameters 5982 ** KEYWORDS: {status parameters} 5983 ** 5984 ** These integer constants designate various run-time status parameters 5985 ** that can be returned by [sqlite3_status()]. 5986 ** 5987 ** <dl> 5988 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 5989 ** <dd>This parameter is the current amount of memory checked out 5990 ** using [sqlite3_malloc()], either directly or indirectly. The 5991 ** figure includes calls made to [sqlite3_malloc()] by the application 5992 ** and internal memory usage by the SQLite library. Scratch memory 5993 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 5994 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 5995 ** this parameter. The amount returned is the sum of the allocation 5996 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 5997 ** 5998 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 5999 ** <dd>This parameter records the largest memory allocation request 6000 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 6001 ** internal equivalents). Only the value returned in the 6002 ** *pHighwater parameter to [sqlite3_status()] is of interest. 6003 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 6004 ** 6005 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 6006 ** <dd>This parameter records the number of separate memory allocations 6007 ** currently checked out.</dd>)^ 6008 ** 6009 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 6010 ** <dd>This parameter returns the number of pages used out of the 6011 ** [pagecache memory allocator] that was configured using 6012 ** [SQLITE_CONFIG_PAGECACHE]. The 6013 ** value returned is in pages, not in bytes.</dd>)^ 6014 ** 6015 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 6016 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 6017 ** <dd>This parameter returns the number of bytes of page cache 6018 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 6019 ** buffer and where forced to overflow to [sqlite3_malloc()]. The 6020 ** returned value includes allocations that overflowed because they 6021 ** where too large (they were larger than the "sz" parameter to 6022 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 6023 ** no space was left in the page cache.</dd>)^ 6024 ** 6025 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 6026 ** <dd>This parameter records the largest memory allocation request 6027 ** handed to [pagecache memory allocator]. Only the value returned in the 6028 ** *pHighwater parameter to [sqlite3_status()] is of interest. 6029 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 6030 ** 6031 ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 6032 ** <dd>This parameter returns the number of allocations used out of the 6033 ** [scratch memory allocator] configured using 6034 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 6035 ** in bytes. Since a single thread may only have one scratch allocation 6036 ** outstanding at time, this parameter also reports the number of threads 6037 ** using scratch memory at the same time.</dd>)^ 6038 ** 6039 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 6040 ** <dd>This parameter returns the number of bytes of scratch memory 6041 ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 6042 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values 6043 ** returned include overflows because the requested allocation was too 6044 ** larger (that is, because the requested allocation was larger than the 6045 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 6046 ** slots were available. 6047 ** </dd>)^ 6048 ** 6049 ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 6050 ** <dd>This parameter records the largest memory allocation request 6051 ** handed to [scratch memory allocator]. Only the value returned in the 6052 ** *pHighwater parameter to [sqlite3_status()] is of interest. 6053 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 6054 ** 6055 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 6056 ** <dd>This parameter records the deepest parser stack. It is only 6057 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 6058 ** </dl> 6059 ** 6060 ** New status parameters may be added from time to time. 6061 */ 6062 #define SQLITE_STATUS_MEMORY_USED 0 6063 #define SQLITE_STATUS_PAGECACHE_USED 1 6064 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 6065 #define SQLITE_STATUS_SCRATCH_USED 3 6066 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4 6067 #define SQLITE_STATUS_MALLOC_SIZE 5 6068 #define SQLITE_STATUS_PARSER_STACK 6 6069 #define SQLITE_STATUS_PAGECACHE_SIZE 7 6070 #define SQLITE_STATUS_SCRATCH_SIZE 8 6071 #define SQLITE_STATUS_MALLOC_COUNT 9 6072 6073 /* 6074 ** CAPI3REF: Database Connection Status 6075 ** 6076 ** ^This interface is used to retrieve runtime status information 6077 ** about a single [database connection]. ^The first argument is the 6078 ** database connection object to be interrogated. ^The second argument 6079 ** is an integer constant, taken from the set of 6080 ** [SQLITE_DBSTATUS options], that 6081 ** determines the parameter to interrogate. The set of 6082 ** [SQLITE_DBSTATUS options] is likely 6083 ** to grow in future releases of SQLite. 6084 ** 6085 ** ^The current value of the requested parameter is written into *pCur 6086 ** and the highest instantaneous value is written into *pHiwtr. ^If 6087 ** the resetFlg is true, then the highest instantaneous value is 6088 ** reset back down to the current value. 6089 ** 6090 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 6091 ** non-zero [error code] on failure. 6092 ** 6093 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 6094 */ 6095 SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 6096 6097 /* 6098 ** CAPI3REF: Status Parameters for database connections 6099 ** KEYWORDS: {SQLITE_DBSTATUS options} 6100 ** 6101 ** These constants are the available integer "verbs" that can be passed as 6102 ** the second argument to the [sqlite3_db_status()] interface. 6103 ** 6104 ** New verbs may be added in future releases of SQLite. Existing verbs 6105 ** might be discontinued. Applications should check the return code from 6106 ** [sqlite3_db_status()] to make sure that the call worked. 6107 ** The [sqlite3_db_status()] interface will return a non-zero error code 6108 ** if a discontinued or unsupported verb is invoked. 6109 ** 6110 ** <dl> 6111 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 6112 ** <dd>This parameter returns the number of lookaside memory slots currently 6113 ** checked out.</dd>)^ 6114 ** 6115 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 6116 ** <dd>This parameter returns the number malloc attempts that were 6117 ** satisfied using lookaside memory. Only the high-water value is meaningful; 6118 ** the current value is always zero.)^ 6119 ** 6120 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 6121 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 6122 ** <dd>This parameter returns the number malloc attempts that might have 6123 ** been satisfied using lookaside memory but failed due to the amount of 6124 ** memory requested being larger than the lookaside slot size. 6125 ** Only the high-water value is meaningful; 6126 ** the current value is always zero.)^ 6127 ** 6128 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 6129 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 6130 ** <dd>This parameter returns the number malloc attempts that might have 6131 ** been satisfied using lookaside memory but failed due to all lookaside 6132 ** memory already being in use. 6133 ** Only the high-water value is meaningful; 6134 ** the current value is always zero.)^ 6135 ** 6136 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 6137 ** <dd>This parameter returns the approximate number of of bytes of heap 6138 ** memory used by all pager caches associated with the database connection.)^ 6139 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 6140 ** 6141 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 6142 ** <dd>This parameter returns the approximate number of of bytes of heap 6143 ** memory used to store the schema for all databases associated 6144 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 6145 ** ^The full amount of memory used by the schemas is reported, even if the 6146 ** schema memory is shared with other database connections due to 6147 ** [shared cache mode] being enabled. 6148 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 6149 ** 6150 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 6151 ** <dd>This parameter returns the approximate number of of bytes of heap 6152 ** and lookaside memory used by all prepared statements associated with 6153 ** the database connection.)^ 6154 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 6155 ** </dd> 6156 ** 6157 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 6158 ** <dd>This parameter returns the number of pager cache hits that have 6159 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 6160 ** is always 0. 6161 ** </dd> 6162 ** 6163 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6164 ** <dd>This parameter returns the number of pager cache misses that have 6165 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6166 ** is always 0. 6167 ** </dd> 6168 ** 6169 ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 6170 ** <dd>This parameter returns the number of dirty cache entries that have 6171 ** been written to disk. Specifically, the number of pages written to the 6172 ** wal file in wal mode databases, or the number of pages written to the 6173 ** database file in rollback mode databases. Any pages written as part of 6174 ** transaction rollback or database recovery operations are not included. 6175 ** If an IO or other error occurs while writing a page to disk, the effect 6176 ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 6177 ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 6178 ** </dd> 6179 ** </dl> 6180 */ 6181 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6182 #define SQLITE_DBSTATUS_CACHE_USED 1 6183 #define SQLITE_DBSTATUS_SCHEMA_USED 2 6184 #define SQLITE_DBSTATUS_STMT_USED 3 6185 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6186 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6187 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 6188 #define SQLITE_DBSTATUS_CACHE_HIT 7 6189 #define SQLITE_DBSTATUS_CACHE_MISS 8 6190 #define SQLITE_DBSTATUS_CACHE_WRITE 9 6191 #define SQLITE_DBSTATUS_MAX 9 /* Largest defined DBSTATUS */ 6192 6193 6194 /* 6195 ** CAPI3REF: Prepared Statement Status 6196 ** 6197 ** ^(Each prepared statement maintains various 6198 ** [SQLITE_STMTSTATUS counters] that measure the number 6199 ** of times it has performed specific operations.)^ These counters can 6200 ** be used to monitor the performance characteristics of the prepared 6201 ** statements. For example, if the number of table steps greatly exceeds 6202 ** the number of table searches or result rows, that would tend to indicate 6203 ** that the prepared statement is using a full table scan rather than 6204 ** an index. 6205 ** 6206 ** ^(This interface is used to retrieve and reset counter values from 6207 ** a [prepared statement]. The first argument is the prepared statement 6208 ** object to be interrogated. The second argument 6209 ** is an integer code for a specific [SQLITE_STMTSTATUS counter] 6210 ** to be interrogated.)^ 6211 ** ^The current value of the requested counter is returned. 6212 ** ^If the resetFlg is true, then the counter is reset to zero after this 6213 ** interface call returns. 6214 ** 6215 ** See also: [sqlite3_status()] and [sqlite3_db_status()]. 6216 */ 6217 SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 6218 6219 /* 6220 ** CAPI3REF: Status Parameters for prepared statements 6221 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 6222 ** 6223 ** These preprocessor macros define integer codes that name counter 6224 ** values associated with the [sqlite3_stmt_status()] interface. 6225 ** The meanings of the various counters are as follows: 6226 ** 6227 ** <dl> 6228 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 6229 ** <dd>^This is the number of times that SQLite has stepped forward in 6230 ** a table as part of a full table scan. Large numbers for this counter 6231 ** may indicate opportunities for performance improvement through 6232 ** careful use of indices.</dd> 6233 ** 6234 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 6235 ** <dd>^This is the number of sort operations that have occurred. 6236 ** A non-zero value in this counter may indicate an opportunity to 6237 ** improvement performance through careful use of indices.</dd> 6238 ** 6239 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 6240 ** <dd>^This is the number of rows inserted into transient indices that 6241 ** were created automatically in order to help joins run faster. 6242 ** A non-zero value in this counter may indicate an opportunity to 6243 ** improvement performance by adding permanent indices that do not 6244 ** need to be reinitialized each time the statement is run.</dd> 6245 ** </dl> 6246 */ 6247 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 6248 #define SQLITE_STMTSTATUS_SORT 2 6249 #define SQLITE_STMTSTATUS_AUTOINDEX 3 6250 6251 /* 6252 ** CAPI3REF: Custom Page Cache Object 6253 ** 6254 ** The sqlite3_pcache type is opaque. It is implemented by 6255 ** the pluggable module. The SQLite core has no knowledge of 6256 ** its size or internal structure and never deals with the 6257 ** sqlite3_pcache object except by holding and passing pointers 6258 ** to the object. 6259 ** 6260 ** See [sqlite3_pcache_methods2] for additional information. 6261 */ 6262 typedef struct sqlite3_pcache sqlite3_pcache; 6263 6264 /* 6265 ** CAPI3REF: Custom Page Cache Object 6266 ** 6267 ** The sqlite3_pcache_page object represents a single page in the 6268 ** page cache. The page cache will allocate instances of this 6269 ** object. Various methods of the page cache use pointers to instances 6270 ** of this object as parameters or as their return value. 6271 ** 6272 ** See [sqlite3_pcache_methods2] for additional information. 6273 */ 6274 typedef struct sqlite3_pcache_page sqlite3_pcache_page; 6275 struct sqlite3_pcache_page { 6276 void *pBuf; /* The content of the page */ 6277 void *pExtra; /* Extra information associated with the page */ 6278 }; 6279 6280 /* 6281 ** CAPI3REF: Application Defined Page Cache. 6282 ** KEYWORDS: {page cache} 6283 ** 6284 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 6285 ** register an alternative page cache implementation by passing in an 6286 ** instance of the sqlite3_pcache_methods2 structure.)^ 6287 ** In many applications, most of the heap memory allocated by 6288 ** SQLite is used for the page cache. 6289 ** By implementing a 6290 ** custom page cache using this API, an application can better control 6291 ** the amount of memory consumed by SQLite, the way in which 6292 ** that memory is allocated and released, and the policies used to 6293 ** determine exactly which parts of a database file are cached and for 6294 ** how long. 6295 ** 6296 ** The alternative page cache mechanism is an 6297 ** extreme measure that is only needed by the most demanding applications. 6298 ** The built-in page cache is recommended for most uses. 6299 ** 6300 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 6301 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence 6302 ** the application may discard the parameter after the call to 6303 ** [sqlite3_config()] returns.)^ 6304 ** 6305 ** [[the xInit() page cache method]] 6306 ** ^(The xInit() method is called once for each effective 6307 ** call to [sqlite3_initialize()])^ 6308 ** (usually only once during the lifetime of the process). ^(The xInit() 6309 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 6310 ** The intent of the xInit() method is to set up global data structures 6311 ** required by the custom page cache implementation. 6312 ** ^(If the xInit() method is NULL, then the 6313 ** built-in default page cache is used instead of the application defined 6314 ** page cache.)^ 6315 ** 6316 ** [[the xShutdown() page cache method]] 6317 ** ^The xShutdown() method is called by [sqlite3_shutdown()]. 6318 ** It can be used to clean up 6319 ** any outstanding resources before process shutdown, if required. 6320 ** ^The xShutdown() method may be NULL. 6321 ** 6322 ** ^SQLite automatically serializes calls to the xInit method, 6323 ** so the xInit method need not be threadsafe. ^The 6324 ** xShutdown method is only called from [sqlite3_shutdown()] so it does 6325 ** not need to be threadsafe either. All other methods must be threadsafe 6326 ** in multithreaded applications. 6327 ** 6328 ** ^SQLite will never invoke xInit() more than once without an intervening 6329 ** call to xShutdown(). 6330 ** 6331 ** [[the xCreate() page cache methods]] 6332 ** ^SQLite invokes the xCreate() method to construct a new cache instance. 6333 ** SQLite will typically create one cache instance for each open database file, 6334 ** though this is not guaranteed. ^The 6335 ** first parameter, szPage, is the size in bytes of the pages that must 6336 ** be allocated by the cache. ^szPage will always a power of two. ^The 6337 ** second parameter szExtra is a number of bytes of extra storage 6338 ** associated with each page cache entry. ^The szExtra parameter will 6339 ** a number less than 250. SQLite will use the 6340 ** extra szExtra bytes on each page to store metadata about the underlying 6341 ** database page on disk. The value passed into szExtra depends 6342 ** on the SQLite version, the target platform, and how SQLite was compiled. 6343 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being 6344 ** created will be used to cache database pages of a file stored on disk, or 6345 ** false if it is used for an in-memory database. The cache implementation 6346 ** does not have to do anything special based with the value of bPurgeable; 6347 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 6348 ** never invoke xUnpin() except to deliberately delete a page. 6349 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 6350 ** false will always have the "discard" flag set to true. 6351 ** ^Hence, a cache created with bPurgeable false will 6352 ** never contain any unpinned pages. 6353 ** 6354 ** [[the xCachesize() page cache method]] 6355 ** ^(The xCachesize() method may be called at any time by SQLite to set the 6356 ** suggested maximum cache-size (number of pages stored by) the cache 6357 ** instance passed as the first argument. This is the value configured using 6358 ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 6359 ** parameter, the implementation is not required to do anything with this 6360 ** value; it is advisory only. 6361 ** 6362 ** [[the xPagecount() page cache methods]] 6363 ** The xPagecount() method must return the number of pages currently 6364 ** stored in the cache, both pinned and unpinned. 6365 ** 6366 ** [[the xFetch() page cache methods]] 6367 ** The xFetch() method locates a page in the cache and returns a pointer to 6368 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 6369 ** The pBuf element of the returned sqlite3_pcache_page object will be a 6370 ** pointer to a buffer of szPage bytes used to store the content of a 6371 ** single database page. The pExtra element of sqlite3_pcache_page will be 6372 ** a pointer to the szExtra bytes of extra storage that SQLite has requested 6373 ** for each entry in the page cache. 6374 ** 6375 ** The page to be fetched is determined by the key. ^The minimum key value 6376 ** is 1. After it has been retrieved using xFetch, the page is considered 6377 ** to be "pinned". 6378 ** 6379 ** If the requested page is already in the page cache, then the page cache 6380 ** implementation must return a pointer to the page buffer with its content 6381 ** intact. If the requested page is not already in the cache, then the 6382 ** cache implementation should use the value of the createFlag 6383 ** parameter to help it determined what action to take: 6384 ** 6385 ** <table border=1 width=85% align=center> 6386 ** <tr><th> createFlag <th> Behavior when page is not already in cache 6387 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6388 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6389 ** Otherwise return NULL. 6390 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6391 ** NULL if allocating a new page is effectively impossible. 6392 ** </table> 6393 ** 6394 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6395 ** will only use a createFlag of 2 after a prior call with a createFlag of 1 6396 ** failed.)^ In between the to xFetch() calls, SQLite may 6397 ** attempt to unpin one or more cache pages by spilling the content of 6398 ** pinned pages to disk and synching the operating system disk cache. 6399 ** 6400 ** [[the xUnpin() page cache method]] 6401 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6402 ** as its second argument. If the third parameter, discard, is non-zero, 6403 ** then the page must be evicted from the cache. 6404 ** ^If the discard parameter is 6405 ** zero, then the page may be discarded or retained at the discretion of 6406 ** page cache implementation. ^The page cache implementation 6407 ** may choose to evict unpinned pages at any time. 6408 ** 6409 ** The cache must not perform any reference counting. A single 6410 ** call to xUnpin() unpins the page regardless of the number of prior calls 6411 ** to xFetch(). 6412 ** 6413 ** [[the xRekey() page cache methods]] 6414 ** The xRekey() method is used to change the key value associated with the 6415 ** page passed as the second argument. If the cache 6416 ** previously contains an entry associated with newKey, it must be 6417 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6418 ** to be pinned. 6419 ** 6420 ** When SQLite calls the xTruncate() method, the cache must discard all 6421 ** existing cache entries with page numbers (keys) greater than or equal 6422 ** to the value of the iLimit parameter passed to xTruncate(). If any 6423 ** of these pages are pinned, they are implicitly unpinned, meaning that 6424 ** they can be safely discarded. 6425 ** 6426 ** [[the xDestroy() page cache method]] 6427 ** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6428 ** All resources associated with the specified cache should be freed. ^After 6429 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6430 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2 6431 ** functions. 6432 ** 6433 ** [[the xShrink() page cache method]] 6434 ** ^SQLite invokes the xShrink() method when it wants the page cache to 6435 ** free up as much of heap memory as possible. The page cache implementation 6436 ** is not obligated to free any memory, but well-behaved implementations should 6437 ** do their best. 6438 */ 6439 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 6440 struct sqlite3_pcache_methods2 { 6441 int iVersion; 6442 void *pArg; 6443 int (*xInit)(void*); 6444 void (*xShutdown)(void*); 6445 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 6446 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6447 int (*xPagecount)(sqlite3_pcache*); 6448 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6449 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 6450 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 6451 unsigned oldKey, unsigned newKey); 6452 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6453 void (*xDestroy)(sqlite3_pcache*); 6454 void (*xShrink)(sqlite3_pcache*); 6455 }; 6456 6457 /* 6458 ** This is the obsolete pcache_methods object that has now been replaced 6459 ** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 6460 ** retained in the header file for backwards compatibility only. 6461 */ 6462 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 6463 struct sqlite3_pcache_methods { 6464 void *pArg; 6465 int (*xInit)(void*); 6466 void (*xShutdown)(void*); 6467 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 6468 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6469 int (*xPagecount)(sqlite3_pcache*); 6470 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6471 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 6472 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 6473 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6474 void (*xDestroy)(sqlite3_pcache*); 6475 }; 6476 6477 6478 /* 6479 ** CAPI3REF: Online Backup Object 6480 ** 6481 ** The sqlite3_backup object records state information about an ongoing 6482 ** online backup operation. ^The sqlite3_backup object is created by 6483 ** a call to [sqlite3_backup_init()] and is destroyed by a call to 6484 ** [sqlite3_backup_finish()]. 6485 ** 6486 ** See Also: [Using the SQLite Online Backup API] 6487 */ 6488 typedef struct sqlite3_backup sqlite3_backup; 6489 6490 /* 6491 ** CAPI3REF: Online Backup API. 6492 ** 6493 ** The backup API copies the content of one database into another. 6494 ** It is useful either for creating backups of databases or 6495 ** for copying in-memory databases to or from persistent files. 6496 ** 6497 ** See Also: [Using the SQLite Online Backup API] 6498 ** 6499 ** ^SQLite holds a write transaction open on the destination database file 6500 ** for the duration of the backup operation. 6501 ** ^The source database is read-locked only while it is being read; 6502 ** it is not locked continuously for the entire backup operation. 6503 ** ^Thus, the backup may be performed on a live source database without 6504 ** preventing other database connections from 6505 ** reading or writing to the source database while the backup is underway. 6506 ** 6507 ** ^(To perform a backup operation: 6508 ** <ol> 6509 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the 6510 ** backup, 6511 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 6512 ** the data between the two databases, and finally 6513 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources 6514 ** associated with the backup operation. 6515 ** </ol>)^ 6516 ** There should be exactly one call to sqlite3_backup_finish() for each 6517 ** successful call to sqlite3_backup_init(). 6518 ** 6519 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 6520 ** 6521 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 6522 ** [database connection] associated with the destination database 6523 ** and the database name, respectively. 6524 ** ^The database name is "main" for the main database, "temp" for the 6525 ** temporary database, or the name specified after the AS keyword in 6526 ** an [ATTACH] statement for an attached database. 6527 ** ^The S and M arguments passed to 6528 ** sqlite3_backup_init(D,N,S,M) identify the [database connection] 6529 ** and database name of the source database, respectively. 6530 ** ^The source and destination [database connections] (parameters S and D) 6531 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 6532 ** an error. 6533 ** 6534 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 6535 ** returned and an error code and error message are stored in the 6536 ** destination [database connection] D. 6537 ** ^The error code and message for the failed call to sqlite3_backup_init() 6538 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 6539 ** [sqlite3_errmsg16()] functions. 6540 ** ^A successful call to sqlite3_backup_init() returns a pointer to an 6541 ** [sqlite3_backup] object. 6542 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 6543 ** sqlite3_backup_finish() functions to perform the specified backup 6544 ** operation. 6545 ** 6546 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 6547 ** 6548 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 6549 ** the source and destination databases specified by [sqlite3_backup] object B. 6550 ** ^If N is negative, all remaining source pages are copied. 6551 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 6552 ** are still more pages to be copied, then the function returns [SQLITE_OK]. 6553 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 6554 ** from source to destination, then it returns [SQLITE_DONE]. 6555 ** ^If an error occurs while running sqlite3_backup_step(B,N), 6556 ** then an [error code] is returned. ^As well as [SQLITE_OK] and 6557 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 6558 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 6559 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 6560 ** 6561 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 6562 ** <ol> 6563 ** <li> the destination database was opened read-only, or 6564 ** <li> the destination database is using write-ahead-log journaling 6565 ** and the destination and source page sizes differ, or 6566 ** <li> the destination database is an in-memory database and the 6567 ** destination and source page sizes differ. 6568 ** </ol>)^ 6569 ** 6570 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 6571 ** the [sqlite3_busy_handler | busy-handler function] 6572 ** is invoked (if one is specified). ^If the 6573 ** busy-handler returns non-zero before the lock is available, then 6574 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 6575 ** sqlite3_backup_step() can be retried later. ^If the source 6576 ** [database connection] 6577 ** is being used to write to the source database when sqlite3_backup_step() 6578 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 6579 ** case the call to sqlite3_backup_step() can be retried later on. ^(If 6580 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 6581 ** [SQLITE_READONLY] is returned, then 6582 ** there is no point in retrying the call to sqlite3_backup_step(). These 6583 ** errors are considered fatal.)^ The application must accept 6584 ** that the backup operation has failed and pass the backup operation handle 6585 ** to the sqlite3_backup_finish() to release associated resources. 6586 ** 6587 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock 6588 ** on the destination file. ^The exclusive lock is not released until either 6589 ** sqlite3_backup_finish() is called or the backup operation is complete 6590 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 6591 ** sqlite3_backup_step() obtains a [shared lock] on the source database that 6592 ** lasts for the duration of the sqlite3_backup_step() call. 6593 ** ^Because the source database is not locked between calls to 6594 ** sqlite3_backup_step(), the source database may be modified mid-way 6595 ** through the backup process. ^If the source database is modified by an 6596 ** external process or via a database connection other than the one being 6597 ** used by the backup operation, then the backup will be automatically 6598 ** restarted by the next call to sqlite3_backup_step(). ^If the source 6599 ** database is modified by the using the same database connection as is used 6600 ** by the backup operation, then the backup database is automatically 6601 ** updated at the same time. 6602 ** 6603 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 6604 ** 6605 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 6606 ** application wishes to abandon the backup operation, the application 6607 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 6608 ** ^The sqlite3_backup_finish() interfaces releases all 6609 ** resources associated with the [sqlite3_backup] object. 6610 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 6611 ** active write-transaction on the destination database is rolled back. 6612 ** The [sqlite3_backup] object is invalid 6613 ** and may not be used following a call to sqlite3_backup_finish(). 6614 ** 6615 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 6616 ** sqlite3_backup_step() errors occurred, regardless or whether or not 6617 ** sqlite3_backup_step() completed. 6618 ** ^If an out-of-memory condition or IO error occurred during any prior 6619 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 6620 ** sqlite3_backup_finish() returns the corresponding [error code]. 6621 ** 6622 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 6623 ** is not a permanent error and does not affect the return value of 6624 ** sqlite3_backup_finish(). 6625 ** 6626 ** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]] 6627 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 6628 ** 6629 ** ^Each call to sqlite3_backup_step() sets two values inside 6630 ** the [sqlite3_backup] object: the number of pages still to be backed 6631 ** up and the total number of pages in the source database file. 6632 ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 6633 ** retrieve these two values, respectively. 6634 ** 6635 ** ^The values returned by these functions are only updated by 6636 ** sqlite3_backup_step(). ^If the source database is modified during a backup 6637 ** operation, then the values are not updated to account for any extra 6638 ** pages that need to be updated or the size of the source database file 6639 ** changing. 6640 ** 6641 ** <b>Concurrent Usage of Database Handles</b> 6642 ** 6643 ** ^The source [database connection] may be used by the application for other 6644 ** purposes while a backup operation is underway or being initialized. 6645 ** ^If SQLite is compiled and configured to support threadsafe database 6646 ** connections, then the source database connection may be used concurrently 6647 ** from within other threads. 6648 ** 6649 ** However, the application must guarantee that the destination 6650 ** [database connection] is not passed to any other API (by any thread) after 6651 ** sqlite3_backup_init() is called and before the corresponding call to 6652 ** sqlite3_backup_finish(). SQLite does not currently check to see 6653 ** if the application incorrectly accesses the destination [database connection] 6654 ** and so no error code is reported, but the operations may malfunction 6655 ** nevertheless. Use of the destination database connection while a 6656 ** backup is in progress might also also cause a mutex deadlock. 6657 ** 6658 ** If running in [shared cache mode], the application must 6659 ** guarantee that the shared cache used by the destination database 6660 ** is not accessed while the backup is running. In practice this means 6661 ** that the application must guarantee that the disk file being 6662 ** backed up to is not accessed by any connection within the process, 6663 ** not just the specific connection that was passed to sqlite3_backup_init(). 6664 ** 6665 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple 6666 ** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 6667 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 6668 ** APIs are not strictly speaking threadsafe. If they are invoked at the 6669 ** same time as another thread is invoking sqlite3_backup_step() it is 6670 ** possible that they return invalid values. 6671 */ 6672 SQLITE_API sqlite3_backup *sqlite3_backup_init( 6673 sqlite3 *pDest, /* Destination database handle */ 6674 const char *zDestName, /* Destination database name */ 6675 sqlite3 *pSource, /* Source database handle */ 6676 const char *zSourceName /* Source database name */ 6677 ); 6678 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage); 6679 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p); 6680 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p); 6681 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p); 6682 6683 /* 6684 ** CAPI3REF: Unlock Notification 6685 ** 6686 ** ^When running in shared-cache mode, a database operation may fail with 6687 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 6688 ** individual tables within the shared-cache cannot be obtained. See 6689 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 6690 ** ^This API may be used to register a callback that SQLite will invoke 6691 ** when the connection currently holding the required lock relinquishes it. 6692 ** ^This API is only available if the library was compiled with the 6693 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 6694 ** 6695 ** See Also: [Using the SQLite Unlock Notification Feature]. 6696 ** 6697 ** ^Shared-cache locks are released when a database connection concludes 6698 ** its current transaction, either by committing it or rolling it back. 6699 ** 6700 ** ^When a connection (known as the blocked connection) fails to obtain a 6701 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 6702 ** identity of the database connection (the blocking connection) that 6703 ** has locked the required resource is stored internally. ^After an 6704 ** application receives an SQLITE_LOCKED error, it may call the 6705 ** sqlite3_unlock_notify() method with the blocked connection handle as 6706 ** the first argument to register for a callback that will be invoked 6707 ** when the blocking connections current transaction is concluded. ^The 6708 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 6709 ** call that concludes the blocking connections transaction. 6710 ** 6711 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 6712 ** there is a chance that the blocking connection will have already 6713 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 6714 ** If this happens, then the specified callback is invoked immediately, 6715 ** from within the call to sqlite3_unlock_notify().)^ 6716 ** 6717 ** ^If the blocked connection is attempting to obtain a write-lock on a 6718 ** shared-cache table, and more than one other connection currently holds 6719 ** a read-lock on the same table, then SQLite arbitrarily selects one of 6720 ** the other connections to use as the blocking connection. 6721 ** 6722 ** ^(There may be at most one unlock-notify callback registered by a 6723 ** blocked connection. If sqlite3_unlock_notify() is called when the 6724 ** blocked connection already has a registered unlock-notify callback, 6725 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 6726 ** called with a NULL pointer as its second argument, then any existing 6727 ** unlock-notify callback is canceled. ^The blocked connections 6728 ** unlock-notify callback may also be canceled by closing the blocked 6729 ** connection using [sqlite3_close()]. 6730 ** 6731 ** The unlock-notify callback is not reentrant. If an application invokes 6732 ** any sqlite3_xxx API functions from within an unlock-notify callback, a 6733 ** crash or deadlock may be the result. 6734 ** 6735 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 6736 ** returns SQLITE_OK. 6737 ** 6738 ** <b>Callback Invocation Details</b> 6739 ** 6740 ** When an unlock-notify callback is registered, the application provides a 6741 ** single void* pointer that is passed to the callback when it is invoked. 6742 ** However, the signature of the callback function allows SQLite to pass 6743 ** it an array of void* context pointers. The first argument passed to 6744 ** an unlock-notify callback is a pointer to an array of void* pointers, 6745 ** and the second is the number of entries in the array. 6746 ** 6747 ** When a blocking connections transaction is concluded, there may be 6748 ** more than one blocked connection that has registered for an unlock-notify 6749 ** callback. ^If two or more such blocked connections have specified the 6750 ** same callback function, then instead of invoking the callback function 6751 ** multiple times, it is invoked once with the set of void* context pointers 6752 ** specified by the blocked connections bundled together into an array. 6753 ** This gives the application an opportunity to prioritize any actions 6754 ** related to the set of unblocked database connections. 6755 ** 6756 ** <b>Deadlock Detection</b> 6757 ** 6758 ** Assuming that after registering for an unlock-notify callback a 6759 ** database waits for the callback to be issued before taking any further 6760 ** action (a reasonable assumption), then using this API may cause the 6761 ** application to deadlock. For example, if connection X is waiting for 6762 ** connection Y's transaction to be concluded, and similarly connection 6763 ** Y is waiting on connection X's transaction, then neither connection 6764 ** will proceed and the system may remain deadlocked indefinitely. 6765 ** 6766 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 6767 ** detection. ^If a given call to sqlite3_unlock_notify() would put the 6768 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no 6769 ** unlock-notify callback is registered. The system is said to be in 6770 ** a deadlocked state if connection A has registered for an unlock-notify 6771 ** callback on the conclusion of connection B's transaction, and connection 6772 ** B has itself registered for an unlock-notify callback when connection 6773 ** A's transaction is concluded. ^Indirect deadlock is also detected, so 6774 ** the system is also considered to be deadlocked if connection B has 6775 ** registered for an unlock-notify callback on the conclusion of connection 6776 ** C's transaction, where connection C is waiting on connection A. ^Any 6777 ** number of levels of indirection are allowed. 6778 ** 6779 ** <b>The "DROP TABLE" Exception</b> 6780 ** 6781 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 6782 ** always appropriate to call sqlite3_unlock_notify(). There is however, 6783 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 6784 ** SQLite checks if there are any currently executing SELECT statements 6785 ** that belong to the same connection. If there are, SQLITE_LOCKED is 6786 ** returned. In this case there is no "blocking connection", so invoking 6787 ** sqlite3_unlock_notify() results in the unlock-notify callback being 6788 ** invoked immediately. If the application then re-attempts the "DROP TABLE" 6789 ** or "DROP INDEX" query, an infinite loop might be the result. 6790 ** 6791 ** One way around this problem is to check the extended error code returned 6792 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the 6793 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 6794 ** the special "DROP TABLE/INDEX" case, the extended error code is just 6795 ** SQLITE_LOCKED.)^ 6796 */ 6797 SQLITE_API int sqlite3_unlock_notify( 6798 sqlite3 *pBlocked, /* Waiting connection */ 6799 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 6800 void *pNotifyArg /* Argument to pass to xNotify */ 6801 ); 6802 6803 6804 /* 6805 ** CAPI3REF: String Comparison 6806 ** 6807 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 6808 ** and extensions to compare the contents of two buffers containing UTF-8 6809 ** strings in a case-independent fashion, using the same definition of "case 6810 ** independence" that SQLite uses internally when comparing identifiers. 6811 */ 6812 SQLITE_API int sqlite3_stricmp(const char *, const char *); 6813 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int); 6814 6815 /* 6816 ** CAPI3REF: Error Logging Interface 6817 ** 6818 ** ^The [sqlite3_log()] interface writes a message into the error log 6819 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 6820 ** ^If logging is enabled, the zFormat string and subsequent arguments are 6821 ** used with [sqlite3_snprintf()] to generate the final output string. 6822 ** 6823 ** The sqlite3_log() interface is intended for use by extensions such as 6824 ** virtual tables, collating functions, and SQL functions. While there is 6825 ** nothing to prevent an application from calling sqlite3_log(), doing so 6826 ** is considered bad form. 6827 ** 6828 ** The zFormat string must not be NULL. 6829 ** 6830 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine 6831 ** will not use dynamically allocated memory. The log message is stored in 6832 ** a fixed-length buffer on the stack. If the log message is longer than 6833 ** a few hundred characters, it will be truncated to the length of the 6834 ** buffer. 6835 */ 6836 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...); 6837 6838 /* 6839 ** CAPI3REF: Write-Ahead Log Commit Hook 6840 ** 6841 ** ^The [sqlite3_wal_hook()] function is used to register a callback that 6842 ** will be invoked each time a database connection commits data to a 6843 ** [write-ahead log] (i.e. whenever a transaction is committed in 6844 ** [journal_mode | journal_mode=WAL mode]). 6845 ** 6846 ** ^The callback is invoked by SQLite after the commit has taken place and 6847 ** the associated write-lock on the database released, so the implementation 6848 ** may read, write or [checkpoint] the database as required. 6849 ** 6850 ** ^The first parameter passed to the callback function when it is invoked 6851 ** is a copy of the third parameter passed to sqlite3_wal_hook() when 6852 ** registering the callback. ^The second is a copy of the database handle. 6853 ** ^The third parameter is the name of the database that was written to - 6854 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 6855 ** is the number of pages currently in the write-ahead log file, 6856 ** including those that were just committed. 6857 ** 6858 ** The callback function should normally return [SQLITE_OK]. ^If an error 6859 ** code is returned, that error will propagate back up through the 6860 ** SQLite code base to cause the statement that provoked the callback 6861 ** to report an error, though the commit will have still occurred. If the 6862 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 6863 ** that does not correspond to any valid SQLite error code, the results 6864 ** are undefined. 6865 ** 6866 ** A single database handle may have at most a single write-ahead log callback 6867 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 6868 ** previously registered write-ahead log callback. ^Note that the 6869 ** [sqlite3_wal_autocheckpoint()] interface and the 6870 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 6871 ** those overwrite any prior [sqlite3_wal_hook()] settings. 6872 */ 6873 SQLITE_API void *sqlite3_wal_hook( 6874 sqlite3*, 6875 int(*)(void *,sqlite3*,const char*,int), 6876 void* 6877 ); 6878 6879 /* 6880 ** CAPI3REF: Configure an auto-checkpoint 6881 ** 6882 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 6883 ** [sqlite3_wal_hook()] that causes any database on [database connection] D 6884 ** to automatically [checkpoint] 6885 ** after committing a transaction if there are N or 6886 ** more frames in the [write-ahead log] file. ^Passing zero or 6887 ** a negative value as the nFrame parameter disables automatic 6888 ** checkpoints entirely. 6889 ** 6890 ** ^The callback registered by this function replaces any existing callback 6891 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 6892 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 6893 ** configured by this function. 6894 ** 6895 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 6896 ** from SQL. 6897 ** 6898 ** ^Every new [database connection] defaults to having the auto-checkpoint 6899 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 6900 ** pages. The use of this interface 6901 ** is only necessary if the default setting is found to be suboptimal 6902 ** for a particular application. 6903 */ 6904 SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 6905 6906 /* 6907 ** CAPI3REF: Checkpoint a database 6908 ** 6909 ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 6910 ** on [database connection] D to be [checkpointed]. ^If X is NULL or an 6911 ** empty string, then a checkpoint is run on all databases of 6912 ** connection D. ^If the database connection D is not in 6913 ** [WAL | write-ahead log mode] then this interface is a harmless no-op. 6914 ** 6915 ** ^The [wal_checkpoint pragma] can be used to invoke this interface 6916 ** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 6917 ** [wal_autocheckpoint pragma] can be used to cause this interface to be 6918 ** run whenever the WAL reaches a certain size threshold. 6919 ** 6920 ** See also: [sqlite3_wal_checkpoint_v2()] 6921 */ 6922 SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 6923 6924 /* 6925 ** CAPI3REF: Checkpoint a database 6926 ** 6927 ** Run a checkpoint operation on WAL database zDb attached to database 6928 ** handle db. The specific operation is determined by the value of the 6929 ** eMode parameter: 6930 ** 6931 ** <dl> 6932 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 6933 ** Checkpoint as many frames as possible without waiting for any database 6934 ** readers or writers to finish. Sync the db file if all frames in the log 6935 ** are checkpointed. This mode is the same as calling 6936 ** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked. 6937 ** 6938 ** <dt>SQLITE_CHECKPOINT_FULL<dd> 6939 ** This mode blocks (calls the busy-handler callback) until there is no 6940 ** database writer and all readers are reading from the most recent database 6941 ** snapshot. It then checkpoints all frames in the log file and syncs the 6942 ** database file. This call blocks database writers while it is running, 6943 ** but not database readers. 6944 ** 6945 ** <dt>SQLITE_CHECKPOINT_RESTART<dd> 6946 ** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after 6947 ** checkpointing the log file it blocks (calls the busy-handler callback) 6948 ** until all readers are reading from the database file only. This ensures 6949 ** that the next client to write to the database file restarts the log file 6950 ** from the beginning. This call blocks database writers while it is running, 6951 ** but not database readers. 6952 ** </dl> 6953 ** 6954 ** If pnLog is not NULL, then *pnLog is set to the total number of frames in 6955 ** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to 6956 ** the total number of checkpointed frames (including any that were already 6957 ** checkpointed when this function is called). *pnLog and *pnCkpt may be 6958 ** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK. 6959 ** If no values are available because of an error, they are both set to -1 6960 ** before returning to communicate this to the caller. 6961 ** 6962 ** All calls obtain an exclusive "checkpoint" lock on the database file. If 6963 ** any other process is running a checkpoint operation at the same time, the 6964 ** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a 6965 ** busy-handler configured, it will not be invoked in this case. 6966 ** 6967 ** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive 6968 ** "writer" lock on the database file. If the writer lock cannot be obtained 6969 ** immediately, and a busy-handler is configured, it is invoked and the writer 6970 ** lock retried until either the busy-handler returns 0 or the lock is 6971 ** successfully obtained. The busy-handler is also invoked while waiting for 6972 ** database readers as described above. If the busy-handler returns 0 before 6973 ** the writer lock is obtained or while waiting for database readers, the 6974 ** checkpoint operation proceeds from that point in the same way as 6975 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 6976 ** without blocking any further. SQLITE_BUSY is returned in this case. 6977 ** 6978 ** If parameter zDb is NULL or points to a zero length string, then the 6979 ** specified operation is attempted on all WAL databases. In this case the 6980 ** values written to output parameters *pnLog and *pnCkpt are undefined. If 6981 ** an SQLITE_BUSY error is encountered when processing one or more of the 6982 ** attached WAL databases, the operation is still attempted on any remaining 6983 ** attached databases and SQLITE_BUSY is returned to the caller. If any other 6984 ** error occurs while processing an attached database, processing is abandoned 6985 ** and the error code returned to the caller immediately. If no error 6986 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached 6987 ** databases, SQLITE_OK is returned. 6988 ** 6989 ** If database zDb is the name of an attached database that is not in WAL 6990 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If 6991 ** zDb is not NULL (or a zero length string) and is not the name of any 6992 ** attached database, SQLITE_ERROR is returned to the caller. 6993 */ 6994 SQLITE_API int sqlite3_wal_checkpoint_v2( 6995 sqlite3 *db, /* Database handle */ 6996 const char *zDb, /* Name of attached database (or NULL) */ 6997 int eMode, /* SQLITE_CHECKPOINT_* value */ 6998 int *pnLog, /* OUT: Size of WAL log in frames */ 6999 int *pnCkpt /* OUT: Total number of frames checkpointed */ 7000 ); 7001 7002 /* 7003 ** CAPI3REF: Checkpoint operation parameters 7004 ** 7005 ** These constants can be used as the 3rd parameter to 7006 ** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()] 7007 ** documentation for additional information about the meaning and use of 7008 ** each of these values. 7009 */ 7010 #define SQLITE_CHECKPOINT_PASSIVE 0 7011 #define SQLITE_CHECKPOINT_FULL 1 7012 #define SQLITE_CHECKPOINT_RESTART 2 7013 7014 /* 7015 ** CAPI3REF: Virtual Table Interface Configuration 7016 ** 7017 ** This function may be called by either the [xConnect] or [xCreate] method 7018 ** of a [virtual table] implementation to configure 7019 ** various facets of the virtual table interface. 7020 ** 7021 ** If this interface is invoked outside the context of an xConnect or 7022 ** xCreate virtual table method then the behavior is undefined. 7023 ** 7024 ** At present, there is only one option that may be configured using 7025 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 7026 ** may be added in the future. 7027 */ 7028 SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...); 7029 7030 /* 7031 ** CAPI3REF: Virtual Table Configuration Options 7032 ** 7033 ** These macros define the various options to the 7034 ** [sqlite3_vtab_config()] interface that [virtual table] implementations 7035 ** can use to customize and optimize their behavior. 7036 ** 7037 ** <dl> 7038 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 7039 ** <dd>Calls of the form 7040 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 7041 ** where X is an integer. If X is zero, then the [virtual table] whose 7042 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 7043 ** support constraints. In this configuration (which is the default) if 7044 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 7045 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 7046 ** specified as part of the users SQL statement, regardless of the actual 7047 ** ON CONFLICT mode specified. 7048 ** 7049 ** If X is non-zero, then the virtual table implementation guarantees 7050 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 7051 ** any modifications to internal or persistent data structures have been made. 7052 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 7053 ** is able to roll back a statement or database transaction, and abandon 7054 ** or continue processing the current SQL statement as appropriate. 7055 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 7056 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 7057 ** had been ABORT. 7058 ** 7059 ** Virtual table implementations that are required to handle OR REPLACE 7060 ** must do so within the [xUpdate] method. If a call to the 7061 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON 7062 ** CONFLICT policy is REPLACE, the virtual table implementation should 7063 ** silently replace the appropriate rows within the xUpdate callback and 7064 ** return SQLITE_OK. Or, if this is not possible, it may return 7065 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 7066 ** constraint handling. 7067 ** </dl> 7068 */ 7069 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 7070 7071 /* 7072 ** CAPI3REF: Determine The Virtual Table Conflict Policy 7073 ** 7074 ** This function may only be called from within a call to the [xUpdate] method 7075 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 7076 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 7077 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 7078 ** of the SQL statement that triggered the call to the [xUpdate] method of the 7079 ** [virtual table]. 7080 */ 7081 SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *); 7082 7083 /* 7084 ** CAPI3REF: Conflict resolution modes 7085 ** 7086 ** These constants are returned by [sqlite3_vtab_on_conflict()] to 7087 ** inform a [virtual table] implementation what the [ON CONFLICT] mode 7088 ** is for the SQL statement being evaluated. 7089 ** 7090 ** Note that the [SQLITE_IGNORE] constant is also used as a potential 7091 ** return value from the [sqlite3_set_authorizer()] callback and that 7092 ** [SQLITE_ABORT] is also a [result code]. 7093 */ 7094 #define SQLITE_ROLLBACK 1 7095 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 7096 #define SQLITE_FAIL 3 7097 /* #define SQLITE_ABORT 4 // Also an error code */ 7098 #define SQLITE_REPLACE 5 7099 7100 7101 7102 /* 7103 ** Undo the hack that converts floating point types to integer for 7104 ** builds on processors without floating point support. 7105 */ 7106 #ifdef SQLITE_OMIT_FLOATING_POINT 7107 # undef double 7108 #endif 7109 7110 #ifdef __cplusplus 7111 } /* End of the 'extern "C"' block */ 7112 #endif 7113 #endif 7114 7115 /* 7116 ** 2010 August 30 7117 ** 7118 ** The author disclaims copyright to this source code. In place of 7119 ** a legal notice, here is a blessing: 7120 ** 7121 ** May you do good and not evil. 7122 ** May you find forgiveness for yourself and forgive others. 7123 ** May you share freely, never taking more than you give. 7124 ** 7125 ************************************************************************* 7126 */ 7127 7128 #ifndef _SQLITE3RTREE_H_ 7129 #define _SQLITE3RTREE_H_ 7130 7131 7132 #ifdef __cplusplus 7133 extern "C" { 7134 #endif 7135 7136 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry; 7137 7138 /* 7139 ** Register a geometry callback named zGeom that can be used as part of an 7140 ** R-Tree geometry query as follows: 7141 ** 7142 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...) 7143 */ 7144 SQLITE_API int sqlite3_rtree_geometry_callback( 7145 sqlite3 *db, 7146 const char *zGeom, 7147 #ifdef SQLITE_RTREE_INT_ONLY 7148 int (*xGeom)(sqlite3_rtree_geometry*, int n, sqlite3_int64 *a, int *pRes), 7149 #else 7150 int (*xGeom)(sqlite3_rtree_geometry*, int n, double *a, int *pRes), 7151 #endif 7152 void *pContext 7153 ); 7154 7155 7156 /* 7157 ** A pointer to a structure of the following type is passed as the first 7158 ** argument to callbacks registered using rtree_geometry_callback(). 7159 */ 7160 struct sqlite3_rtree_geometry { 7161 void *pContext; /* Copy of pContext passed to s_r_g_c() */ 7162 int nParam; /* Size of array aParam[] */ 7163 double *aParam; /* Parameters passed to SQL geom function */ 7164 void *pUser; /* Callback implementation user data */ 7165 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */ 7166 }; 7167 7168 7169 #ifdef __cplusplus 7170 } /* end of the 'extern "C"' block */ 7171 #endif 7172 7173 #endif /* ifndef _SQLITE3RTREE_H_ */ 7174