sqlite3.h
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 "3.7.8" 111 #define SQLITE_VERSION_NUMBER 3007008 112 #define SQLITE_SOURCE_ID "2011-09-19 14:49:19 3e0da808d2f5b4d12046e05980ca04578f581177" 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 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 ** is its destructor. There are many other interfaces (such as 223 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 224 ** [sqlite3_busy_timeout()] to name but three) that are methods on an 225 ** sqlite3 object. 226 */ 227 typedef struct sqlite3 sqlite3; 228 229 /* 230 ** CAPI3REF: 64-Bit Integer Types 231 ** KEYWORDS: sqlite_int64 sqlite_uint64 232 ** 233 ** Because there is no cross-platform way to specify 64-bit integer types 234 ** SQLite includes typedefs for 64-bit signed and unsigned integers. 235 ** 236 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 237 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards 238 ** compatibility only. 239 ** 240 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values 241 ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 242 ** sqlite3_uint64 and sqlite_uint64 types can store integer values 243 ** between 0 and +18446744073709551615 inclusive. 244 */ 245 #ifdef SQLITE_INT64_TYPE 246 typedef SQLITE_INT64_TYPE sqlite_int64; 247 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 248 #elif defined(_MSC_VER) || defined(__BORLANDC__) 249 typedef __int64 sqlite_int64; 250 typedef unsigned __int64 sqlite_uint64; 251 #else 252 typedef long long int sqlite_int64; 253 typedef unsigned long long int sqlite_uint64; 254 #endif 255 typedef sqlite_int64 sqlite3_int64; 256 typedef sqlite_uint64 sqlite3_uint64; 257 258 /* 259 ** If compiling for a processor that lacks floating point support, 260 ** substitute integer for floating-point. 261 */ 262 #ifdef SQLITE_OMIT_FLOATING_POINT 263 # define double sqlite3_int64 264 #endif 265 266 /* 267 ** CAPI3REF: Closing A Database Connection 268 ** 269 ** ^The sqlite3_close() routine is the destructor for the [sqlite3] object. 270 ** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is 271 ** successfully destroyed and all associated resources are deallocated. 272 ** 273 ** Applications must [sqlite3_finalize | finalize] all [prepared statements] 274 ** and [sqlite3_blob_close | close] all [BLOB handles] associated with 275 ** the [sqlite3] object prior to attempting to close the object. ^If 276 ** sqlite3_close() is called on a [database connection] that still has 277 ** outstanding [prepared statements] or [BLOB handles], then it returns 278 ** SQLITE_BUSY. 279 ** 280 ** ^If [sqlite3_close()] is invoked while a transaction is open, 281 ** the transaction is automatically rolled back. 282 ** 283 ** The C parameter to [sqlite3_close(C)] must be either a NULL 284 ** pointer or an [sqlite3] object pointer obtained 285 ** from [sqlite3_open()], [sqlite3_open16()], or 286 ** [sqlite3_open_v2()], and not previously closed. 287 ** ^Calling sqlite3_close() with a NULL pointer argument is a 288 ** harmless no-op. 289 */ 290 SQLITE_API int sqlite3_close(sqlite3 *); 291 292 /* 293 ** The type for a callback function. 294 ** This is legacy and deprecated. It is included for historical 295 ** compatibility and is not documented. 296 */ 297 typedef int (*sqlite3_callback)(void*,int,char**, char**); 298 299 /* 300 ** CAPI3REF: One-Step Query Execution Interface 301 ** 302 ** The sqlite3_exec() interface is a convenience wrapper around 303 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 304 ** that allows an application to run multiple statements of SQL 305 ** without having to use a lot of C code. 306 ** 307 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 308 ** semicolon-separate SQL statements passed into its 2nd argument, 309 ** in the context of the [database connection] passed in as its 1st 310 ** argument. ^If the callback function of the 3rd argument to 311 ** sqlite3_exec() is not NULL, then it is invoked for each result row 312 ** coming out of the evaluated SQL statements. ^The 4th argument to 313 ** sqlite3_exec() is relayed through to the 1st argument of each 314 ** callback invocation. ^If the callback pointer to sqlite3_exec() 315 ** is NULL, then no callback is ever invoked and result rows are 316 ** ignored. 317 ** 318 ** ^If an error occurs while evaluating the SQL statements passed into 319 ** sqlite3_exec(), then execution of the current statement stops and 320 ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 321 ** is not NULL then any error message is written into memory obtained 322 ** from [sqlite3_malloc()] and passed back through the 5th parameter. 323 ** To avoid memory leaks, the application should invoke [sqlite3_free()] 324 ** on error message strings returned through the 5th parameter of 325 ** of sqlite3_exec() after the error message string is no longer needed. 326 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 327 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 328 ** NULL before returning. 329 ** 330 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 331 ** routine returns SQLITE_ABORT without invoking the callback again and 332 ** without running any subsequent SQL statements. 333 ** 334 ** ^The 2nd argument to the sqlite3_exec() callback function is the 335 ** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 336 ** callback is an array of pointers to strings obtained as if from 337 ** [sqlite3_column_text()], one for each column. ^If an element of a 338 ** result row is NULL then the corresponding string pointer for the 339 ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 340 ** sqlite3_exec() callback is an array of pointers to strings where each 341 ** entry represents the name of corresponding result column as obtained 342 ** from [sqlite3_column_name()]. 343 ** 344 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 345 ** to an empty string, or a pointer that contains only whitespace and/or 346 ** SQL comments, then no SQL statements are evaluated and the database 347 ** is not changed. 348 ** 349 ** Restrictions: 350 ** 351 ** <ul> 352 ** <li> The application must insure that the 1st parameter to sqlite3_exec() 353 ** is a valid and open [database connection]. 354 ** <li> The application must not close [database connection] specified by 355 ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 356 ** <li> The application must not modify the SQL statement text passed into 357 ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 358 ** </ul> 359 */ 360 SQLITE_API int sqlite3_exec( 361 sqlite3*, /* An open database */ 362 const char *sql, /* SQL to be evaluated */ 363 int (*callback)(void*,int,char**,char**), /* Callback function */ 364 void *, /* 1st argument to callback */ 365 char **errmsg /* Error msg written here */ 366 ); 367 368 /* 369 ** CAPI3REF: Result Codes 370 ** KEYWORDS: SQLITE_OK {error code} {error codes} 371 ** KEYWORDS: {result code} {result codes} 372 ** 373 ** Many SQLite functions return an integer result code from the set shown 374 ** here in order to indicates success or failure. 375 ** 376 ** New error codes may be added in future versions of SQLite. 377 ** 378 ** See also: [SQLITE_IOERR_READ | extended result codes], 379 ** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes]. 380 */ 381 #define SQLITE_OK 0 /* Successful result */ 382 /* beginning-of-error-codes */ 383 #define SQLITE_ERROR 1 /* SQL error or missing database */ 384 #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 385 #define SQLITE_PERM 3 /* Access permission denied */ 386 #define SQLITE_ABORT 4 /* Callback routine requested an abort */ 387 #define SQLITE_BUSY 5 /* The database file is locked */ 388 #define SQLITE_LOCKED 6 /* A table in the database is locked */ 389 #define SQLITE_NOMEM 7 /* A malloc() failed */ 390 #define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 391 #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 392 #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 393 #define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 394 #define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 395 #define SQLITE_FULL 13 /* Insertion failed because database is full */ 396 #define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 397 #define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 398 #define SQLITE_EMPTY 16 /* Database is empty */ 399 #define SQLITE_SCHEMA 17 /* The database schema changed */ 400 #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 401 #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 402 #define SQLITE_MISMATCH 20 /* Data type mismatch */ 403 #define SQLITE_MISUSE 21 /* Library used incorrectly */ 404 #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 405 #define SQLITE_AUTH 23 /* Authorization denied */ 406 #define SQLITE_FORMAT 24 /* Auxiliary database format error */ 407 #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 408 #define SQLITE_NOTADB 26 /* File opened that is not a database file */ 409 #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 410 #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 411 /* end-of-error-codes */ 412 413 /* 414 ** CAPI3REF: Extended Result Codes 415 ** KEYWORDS: {extended error code} {extended error codes} 416 ** KEYWORDS: {extended result code} {extended result codes} 417 ** 418 ** In its default configuration, SQLite API routines return one of 26 integer 419 ** [SQLITE_OK | result codes]. However, experience has shown that many of 420 ** these result codes are too coarse-grained. They do not provide as 421 ** much information about problems as programmers might like. In an effort to 422 ** address this, newer versions of SQLite (version 3.3.8 and later) include 423 ** support for additional result codes that provide more detailed information 424 ** about errors. The extended result codes are enabled or disabled 425 ** on a per database connection basis using the 426 ** [sqlite3_extended_result_codes()] API. 427 ** 428 ** Some of the available extended result codes are listed here. 429 ** One may expect the number of extended result codes will be expand 430 ** over time. Software that uses extended result codes should expect 431 ** to see new result codes in future releases of SQLite. 432 ** 433 ** The SQLITE_OK result code will never be extended. It will always 434 ** be exactly zero. 435 */ 436 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 437 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 438 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 439 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 440 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 441 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 442 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 443 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 444 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 445 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 446 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 447 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 448 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 449 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 450 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 451 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 452 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 453 #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 454 #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 455 #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 456 #define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 457 #define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 458 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 459 #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 460 #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 461 #define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 462 #define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 463 #define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 464 465 /* 466 ** CAPI3REF: Flags For File Open Operations 467 ** 468 ** These bit values are intended for use in the 469 ** 3rd parameter to the [sqlite3_open_v2()] interface and 470 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 471 */ 472 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 473 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 474 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 475 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 476 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 477 #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 478 #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 479 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 480 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 481 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 482 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 483 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 484 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 485 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 486 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 487 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 488 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 489 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 490 #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 491 492 /* Reserved: 0x00F00000 */ 493 494 /* 495 ** CAPI3REF: Device Characteristics 496 ** 497 ** The xDeviceCharacteristics method of the [sqlite3_io_methods] 498 ** object returns an integer which is a vector of the these 499 ** bit values expressing I/O characteristics of the mass storage 500 ** device that holds the file that the [sqlite3_io_methods] 501 ** refers to. 502 ** 503 ** The SQLITE_IOCAP_ATOMIC property means that all writes of 504 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 505 ** mean that writes of blocks that are nnn bytes in size and 506 ** are aligned to an address which is an integer multiple of 507 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 508 ** that when data is appended to a file, the data is appended 509 ** first then the size of the file is extended, never the other 510 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 511 ** information is written to disk in the same order as calls 512 ** to xWrite(). 513 */ 514 #define SQLITE_IOCAP_ATOMIC 0x00000001 515 #define SQLITE_IOCAP_ATOMIC512 0x00000002 516 #define SQLITE_IOCAP_ATOMIC1K 0x00000004 517 #define SQLITE_IOCAP_ATOMIC2K 0x00000008 518 #define SQLITE_IOCAP_ATOMIC4K 0x00000010 519 #define SQLITE_IOCAP_ATOMIC8K 0x00000020 520 #define SQLITE_IOCAP_ATOMIC16K 0x00000040 521 #define SQLITE_IOCAP_ATOMIC32K 0x00000080 522 #define SQLITE_IOCAP_ATOMIC64K 0x00000100 523 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200 524 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400 525 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 526 527 /* 528 ** CAPI3REF: File Locking Levels 529 ** 530 ** SQLite uses one of these integer values as the second 531 ** argument to calls it makes to the xLock() and xUnlock() methods 532 ** of an [sqlite3_io_methods] object. 533 */ 534 #define SQLITE_LOCK_NONE 0 535 #define SQLITE_LOCK_SHARED 1 536 #define SQLITE_LOCK_RESERVED 2 537 #define SQLITE_LOCK_PENDING 3 538 #define SQLITE_LOCK_EXCLUSIVE 4 539 540 /* 541 ** CAPI3REF: Synchronization Type Flags 542 ** 543 ** When SQLite invokes the xSync() method of an 544 ** [sqlite3_io_methods] object it uses a combination of 545 ** these integer values as the second argument. 546 ** 547 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 548 ** sync operation only needs to flush data to mass storage. Inode 549 ** information need not be flushed. If the lower four bits of the flag 550 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 551 ** If the lower four bits equal SQLITE_SYNC_FULL, that means 552 ** to use Mac OS X style fullsync instead of fsync(). 553 ** 554 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 555 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 556 ** settings. The [synchronous pragma] determines when calls to the 557 ** xSync VFS method occur and applies uniformly across all platforms. 558 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 559 ** energetic or rigorous or forceful the sync operations are and 560 ** only make a difference on Mac OSX for the default SQLite code. 561 ** (Third-party VFS implementations might also make the distinction 562 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 563 ** operating systems natively supported by SQLite, only Mac OSX 564 ** cares about the difference.) 565 */ 566 #define SQLITE_SYNC_NORMAL 0x00002 567 #define SQLITE_SYNC_FULL 0x00003 568 #define SQLITE_SYNC_DATAONLY 0x00010 569 570 /* 571 ** CAPI3REF: OS Interface Open File Handle 572 ** 573 ** An [sqlite3_file] object represents an open file in the 574 ** [sqlite3_vfs | OS interface layer]. Individual OS interface 575 ** implementations will 576 ** want to subclass this object by appending additional fields 577 ** for their own use. The pMethods entry is a pointer to an 578 ** [sqlite3_io_methods] object that defines methods for performing 579 ** I/O operations on the open file. 580 */ 581 typedef struct sqlite3_file sqlite3_file; 582 struct sqlite3_file { 583 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 584 }; 585 586 /* 587 ** CAPI3REF: OS Interface File Virtual Methods Object 588 ** 589 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an 590 ** [sqlite3_file] object (or, more commonly, a subclass of the 591 ** [sqlite3_file] object) with a pointer to an instance of this object. 592 ** This object defines the methods used to perform various operations 593 ** against the open file represented by the [sqlite3_file] object. 594 ** 595 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 596 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 597 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 598 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 599 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 600 ** to NULL. 601 ** 602 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 603 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 604 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 605 ** flag may be ORed in to indicate that only the data of the file 606 ** and not its inode needs to be synced. 607 ** 608 ** The integer values to xLock() and xUnlock() are one of 609 ** <ul> 610 ** <li> [SQLITE_LOCK_NONE], 611 ** <li> [SQLITE_LOCK_SHARED], 612 ** <li> [SQLITE_LOCK_RESERVED], 613 ** <li> [SQLITE_LOCK_PENDING], or 614 ** <li> [SQLITE_LOCK_EXCLUSIVE]. 615 ** </ul> 616 ** xLock() increases the lock. xUnlock() decreases the lock. 617 ** The xCheckReservedLock() method checks whether any database connection, 618 ** either in this process or in some other process, is holding a RESERVED, 619 ** PENDING, or EXCLUSIVE lock on the file. It returns true 620 ** if such a lock exists and false otherwise. 621 ** 622 ** The xFileControl() method is a generic interface that allows custom 623 ** VFS implementations to directly control an open file using the 624 ** [sqlite3_file_control()] interface. The second "op" argument is an 625 ** integer opcode. The third argument is a generic pointer intended to 626 ** point to a structure that may contain arguments or space in which to 627 ** write return values. Potential uses for xFileControl() might be 628 ** functions to enable blocking locks with timeouts, to change the 629 ** locking strategy (for example to use dot-file locks), to inquire 630 ** about the status of a lock, or to break stale locks. The SQLite 631 ** core reserves all opcodes less than 100 for its own use. 632 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 633 ** Applications that define a custom xFileControl method should use opcodes 634 ** greater than 100 to avoid conflicts. VFS implementations should 635 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not 636 ** recognize. 637 ** 638 ** The xSectorSize() method returns the sector size of the 639 ** device that underlies the file. The sector size is the 640 ** minimum write that can be performed without disturbing 641 ** other bytes in the file. The xDeviceCharacteristics() 642 ** method returns a bit vector describing behaviors of the 643 ** underlying device: 644 ** 645 ** <ul> 646 ** <li> [SQLITE_IOCAP_ATOMIC] 647 ** <li> [SQLITE_IOCAP_ATOMIC512] 648 ** <li> [SQLITE_IOCAP_ATOMIC1K] 649 ** <li> [SQLITE_IOCAP_ATOMIC2K] 650 ** <li> [SQLITE_IOCAP_ATOMIC4K] 651 ** <li> [SQLITE_IOCAP_ATOMIC8K] 652 ** <li> [SQLITE_IOCAP_ATOMIC16K] 653 ** <li> [SQLITE_IOCAP_ATOMIC32K] 654 ** <li> [SQLITE_IOCAP_ATOMIC64K] 655 ** <li> [SQLITE_IOCAP_SAFE_APPEND] 656 ** <li> [SQLITE_IOCAP_SEQUENTIAL] 657 ** </ul> 658 ** 659 ** The SQLITE_IOCAP_ATOMIC property means that all writes of 660 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 661 ** mean that writes of blocks that are nnn bytes in size and 662 ** are aligned to an address which is an integer multiple of 663 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 664 ** that when data is appended to a file, the data is appended 665 ** first then the size of the file is extended, never the other 666 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 667 ** information is written to disk in the same order as calls 668 ** to xWrite(). 669 ** 670 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 671 ** in the unread portions of the buffer with zeros. A VFS that 672 ** fails to zero-fill short reads might seem to work. However, 673 ** failure to zero-fill short reads will eventually lead to 674 ** database corruption. 675 */ 676 typedef struct sqlite3_io_methods sqlite3_io_methods; 677 struct sqlite3_io_methods { 678 int iVersion; 679 int (*xClose)(sqlite3_file*); 680 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 681 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 682 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 683 int (*xSync)(sqlite3_file*, int flags); 684 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 685 int (*xLock)(sqlite3_file*, int); 686 int (*xUnlock)(sqlite3_file*, int); 687 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 688 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 689 int (*xSectorSize)(sqlite3_file*); 690 int (*xDeviceCharacteristics)(sqlite3_file*); 691 /* Methods above are valid for version 1 */ 692 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 693 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 694 void (*xShmBarrier)(sqlite3_file*); 695 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 696 /* Methods above are valid for version 2 */ 697 /* Additional methods may be added in future releases */ 698 }; 699 700 /* 701 ** CAPI3REF: Standard File Control Opcodes 702 ** 703 ** These integer constants are opcodes for the xFileControl method 704 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 705 ** interface. 706 ** 707 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 708 ** opcode causes the xFileControl method to write the current state of 709 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 710 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 711 ** into an integer that the pArg argument points to. This capability 712 ** is used during testing and only needs to be supported when SQLITE_TEST 713 ** is defined. 714 ** 715 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 716 ** layer a hint of how large the database file will grow to be during the 717 ** current transaction. This hint is not guaranteed to be accurate but it 718 ** is often close. The underlying VFS might choose to preallocate database 719 ** file space based on this hint in order to help writes to the database 720 ** file run faster. 721 ** 722 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 723 ** extends and truncates the database file in chunks of a size specified 724 ** by the user. The fourth argument to [sqlite3_file_control()] should 725 ** point to an integer (type int) containing the new chunk-size to use 726 ** for the nominated database. Allocating database file space in large 727 ** chunks (say 1MB at a time), may reduce file-system fragmentation and 728 ** improve performance on some systems. 729 ** 730 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 731 ** to the [sqlite3_file] object associated with a particular database 732 ** connection. See the [sqlite3_file_control()] documentation for 733 ** additional information. 734 ** 735 ** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by 736 ** SQLite and sent to all VFSes in place of a call to the xSync method 737 ** when the database connection has [PRAGMA synchronous] set to OFF.)^ 738 ** Some specialized VFSes need this signal in order to operate correctly 739 ** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most 740 ** VFSes do not need this signal and should silently ignore this opcode. 741 ** Applications should not call [sqlite3_file_control()] with this 742 ** opcode as doing so may disrupt the operation of the specialized VFSes 743 ** that do require it. 744 ** 745 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 746 ** retry counts and intervals for certain disk I/O operations for the 747 ** windows [VFS] in order to work to provide robustness against 748 ** anti-virus programs. By default, the windows VFS will retry file read, 749 ** file write, and file delete opertions up to 10 times, with a delay 750 ** of 25 milliseconds before the first retry and with the delay increasing 751 ** by an additional 25 milliseconds with each subsequent retry. This 752 ** opcode allows those to values (10 retries and 25 milliseconds of delay) 753 ** to be adjusted. The values are changed for all database connections 754 ** within the same process. The argument is a pointer to an array of two 755 ** integers where the first integer i the new retry count and the second 756 ** integer is the delay. If either integer is negative, then the setting 757 ** is not changed but instead the prior value of that setting is written 758 ** into the array entry, allowing the current retry settings to be 759 ** interrogated. The zDbName parameter is ignored. 760 ** 761 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 762 ** persistent [WAL | Write AHead Log] setting. By default, the auxiliary 763 ** write ahead log and shared memory files used for transaction control 764 ** are automatically deleted when the latest connection to the database 765 ** closes. Setting persistent WAL mode causes those files to persist after 766 ** close. Persisting the files is useful when other processes that do not 767 ** have write permission on the directory containing the database file want 768 ** to read the database file, as the WAL and shared memory files must exist 769 ** in order for the database to be readable. The fourth parameter to 770 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 771 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 772 ** WAL mode. If the integer is -1, then it is overwritten with the current 773 ** WAL persistence setting. 774 ** 775 */ 776 #define SQLITE_FCNTL_LOCKSTATE 1 777 #define SQLITE_GET_LOCKPROXYFILE 2 778 #define SQLITE_SET_LOCKPROXYFILE 3 779 #define SQLITE_LAST_ERRNO 4 780 #define SQLITE_FCNTL_SIZE_HINT 5 781 #define SQLITE_FCNTL_CHUNK_SIZE 6 782 #define SQLITE_FCNTL_FILE_POINTER 7 783 #define SQLITE_FCNTL_SYNC_OMITTED 8 784 #define SQLITE_FCNTL_WIN32_AV_RETRY 9 785 #define SQLITE_FCNTL_PERSIST_WAL 10 786 787 /* 788 ** CAPI3REF: Mutex Handle 789 ** 790 ** The mutex module within SQLite defines [sqlite3_mutex] to be an 791 ** abstract type for a mutex object. The SQLite core never looks 792 ** at the internal representation of an [sqlite3_mutex]. It only 793 ** deals with pointers to the [sqlite3_mutex] object. 794 ** 795 ** Mutexes are created using [sqlite3_mutex_alloc()]. 796 */ 797 typedef struct sqlite3_mutex sqlite3_mutex; 798 799 /* 800 ** CAPI3REF: OS Interface Object 801 ** 802 ** An instance of the sqlite3_vfs object defines the interface between 803 ** the SQLite core and the underlying operating system. The "vfs" 804 ** in the name of the object stands for "virtual file system". See 805 ** the [VFS | VFS documentation] for further information. 806 ** 807 ** The value of the iVersion field is initially 1 but may be larger in 808 ** future versions of SQLite. Additional fields may be appended to this 809 ** object when the iVersion value is increased. Note that the structure 810 ** of the sqlite3_vfs object changes in the transaction between 811 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 812 ** modified. 813 ** 814 ** The szOsFile field is the size of the subclassed [sqlite3_file] 815 ** structure used by this VFS. mxPathname is the maximum length of 816 ** a pathname in this VFS. 817 ** 818 ** Registered sqlite3_vfs objects are kept on a linked list formed by 819 ** the pNext pointer. The [sqlite3_vfs_register()] 820 ** and [sqlite3_vfs_unregister()] interfaces manage this list 821 ** in a thread-safe way. The [sqlite3_vfs_find()] interface 822 ** searches the list. Neither the application code nor the VFS 823 ** implementation should use the pNext pointer. 824 ** 825 ** The pNext field is the only field in the sqlite3_vfs 826 ** structure that SQLite will ever modify. SQLite will only access 827 ** or modify this field while holding a particular static mutex. 828 ** The application should never modify anything within the sqlite3_vfs 829 ** object once the object has been registered. 830 ** 831 ** The zName field holds the name of the VFS module. The name must 832 ** be unique across all VFS modules. 833 ** 834 ** [[sqlite3_vfs.xOpen]] 835 ** ^SQLite guarantees that the zFilename parameter to xOpen 836 ** is either a NULL pointer or string obtained 837 ** from xFullPathname() with an optional suffix added. 838 ** ^If a suffix is added to the zFilename parameter, it will 839 ** consist of a single "-" character followed by no more than 840 ** 10 alphanumeric and/or "-" characters. 841 ** ^SQLite further guarantees that 842 ** the string will be valid and unchanged until xClose() is 843 ** called. Because of the previous sentence, 844 ** the [sqlite3_file] can safely store a pointer to the 845 ** filename if it needs to remember the filename for some reason. 846 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen 847 ** must invent its own temporary name for the file. ^Whenever the 848 ** xFilename parameter is NULL it will also be the case that the 849 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 850 ** 851 ** The flags argument to xOpen() includes all bits set in 852 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 853 ** or [sqlite3_open16()] is used, then flags includes at least 854 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 855 ** If xOpen() opens a file read-only then it sets *pOutFlags to 856 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 857 ** 858 ** ^(SQLite will also add one of the following flags to the xOpen() 859 ** call, depending on the object being opened: 860 ** 861 ** <ul> 862 ** <li> [SQLITE_OPEN_MAIN_DB] 863 ** <li> [SQLITE_OPEN_MAIN_JOURNAL] 864 ** <li> [SQLITE_OPEN_TEMP_DB] 865 ** <li> [SQLITE_OPEN_TEMP_JOURNAL] 866 ** <li> [SQLITE_OPEN_TRANSIENT_DB] 867 ** <li> [SQLITE_OPEN_SUBJOURNAL] 868 ** <li> [SQLITE_OPEN_MASTER_JOURNAL] 869 ** <li> [SQLITE_OPEN_WAL] 870 ** </ul>)^ 871 ** 872 ** The file I/O implementation can use the object type flags to 873 ** change the way it deals with files. For example, an application 874 ** that does not care about crash recovery or rollback might make 875 ** the open of a journal file a no-op. Writes to this journal would 876 ** also be no-ops, and any attempt to read the journal would return 877 ** SQLITE_IOERR. Or the implementation might recognize that a database 878 ** file will be doing page-aligned sector reads and writes in a random 879 ** order and set up its I/O subsystem accordingly. 880 ** 881 ** SQLite might also add one of the following flags to the xOpen method: 882 ** 883 ** <ul> 884 ** <li> [SQLITE_OPEN_DELETEONCLOSE] 885 ** <li> [SQLITE_OPEN_EXCLUSIVE] 886 ** </ul> 887 ** 888 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 889 ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 890 ** will be set for TEMP databases and their journals, transient 891 ** databases, and subjournals. 892 ** 893 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 894 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly 895 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 896 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 897 ** SQLITE_OPEN_CREATE, is used to indicate that file should always 898 ** be created, and that it is an error if it already exists. 899 ** It is <i>not</i> used to indicate the file should be opened 900 ** for exclusive access. 901 ** 902 ** ^At least szOsFile bytes of memory are allocated by SQLite 903 ** to hold the [sqlite3_file] structure passed as the third 904 ** argument to xOpen. The xOpen method does not have to 905 ** allocate the structure; it should just fill it in. Note that 906 ** the xOpen method must set the sqlite3_file.pMethods to either 907 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 908 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 909 ** element will be valid after xOpen returns regardless of the success 910 ** or failure of the xOpen call. 911 ** 912 ** [[sqlite3_vfs.xAccess]] 913 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 914 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 915 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 916 ** to test whether a file is at least readable. The file can be a 917 ** directory. 918 ** 919 ** ^SQLite will always allocate at least mxPathname+1 bytes for the 920 ** output buffer xFullPathname. The exact size of the output buffer 921 ** is also passed as a parameter to both methods. If the output buffer 922 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 923 ** handled as a fatal error by SQLite, vfs implementations should endeavor 924 ** to prevent this by setting mxPathname to a sufficiently large value. 925 ** 926 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 927 ** interfaces are not strictly a part of the filesystem, but they are 928 ** included in the VFS structure for completeness. 929 ** The xRandomness() function attempts to return nBytes bytes 930 ** of good-quality randomness into zOut. The return value is 931 ** the actual number of bytes of randomness obtained. 932 ** The xSleep() method causes the calling thread to sleep for at 933 ** least the number of microseconds given. ^The xCurrentTime() 934 ** method returns a Julian Day Number for the current date and time as 935 ** a floating point value. 936 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 937 ** Day Number multiplied by 86400000 (the number of milliseconds in 938 ** a 24-hour day). 939 ** ^SQLite will use the xCurrentTimeInt64() method to get the current 940 ** date and time if that method is available (if iVersion is 2 or 941 ** greater and the function pointer is not NULL) and will fall back 942 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 943 ** 944 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 945 ** are not used by the SQLite core. These optional interfaces are provided 946 ** by some VFSes to facilitate testing of the VFS code. By overriding 947 ** system calls with functions under its control, a test program can 948 ** simulate faults and error conditions that would otherwise be difficult 949 ** or impossible to induce. The set of system calls that can be overridden 950 ** varies from one VFS to another, and from one version of the same VFS to the 951 ** next. Applications that use these interfaces must be prepared for any 952 ** or all of these interfaces to be NULL or for their behavior to change 953 ** from one release to the next. Applications must not attempt to access 954 ** any of these methods if the iVersion of the VFS is less than 3. 955 */ 956 typedef struct sqlite3_vfs sqlite3_vfs; 957 typedef void (*sqlite3_syscall_ptr)(void); 958 struct sqlite3_vfs { 959 int iVersion; /* Structure version number (currently 3) */ 960 int szOsFile; /* Size of subclassed sqlite3_file */ 961 int mxPathname; /* Maximum file pathname length */ 962 sqlite3_vfs *pNext; /* Next registered VFS */ 963 const char *zName; /* Name of this virtual file system */ 964 void *pAppData; /* Pointer to application-specific data */ 965 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 966 int flags, int *pOutFlags); 967 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 968 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 969 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 970 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 971 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 972 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 973 void (*xDlClose)(sqlite3_vfs*, void*); 974 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 975 int (*xSleep)(sqlite3_vfs*, int microseconds); 976 int (*xCurrentTime)(sqlite3_vfs*, double*); 977 int (*xGetLastError)(sqlite3_vfs*, int, char *); 978 /* 979 ** The methods above are in version 1 of the sqlite_vfs object 980 ** definition. Those that follow are added in version 2 or later 981 */ 982 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 983 /* 984 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 985 ** Those below are for version 3 and greater. 986 */ 987 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 988 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 989 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 990 /* 991 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 992 ** New fields may be appended in figure versions. The iVersion 993 ** value will increment whenever this happens. 994 */ 995 }; 996 997 /* 998 ** CAPI3REF: Flags for the xAccess VFS method 999 ** 1000 ** These integer constants can be used as the third parameter to 1001 ** the xAccess method of an [sqlite3_vfs] object. They determine 1002 ** what kind of permissions the xAccess method is looking for. 1003 ** With SQLITE_ACCESS_EXISTS, the xAccess method 1004 ** simply checks whether the file exists. 1005 ** With SQLITE_ACCESS_READWRITE, the xAccess method 1006 ** checks whether the named directory is both readable and writable 1007 ** (in other words, if files can be added, removed, and renamed within 1008 ** the directory). 1009 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1010 ** [temp_store_directory pragma], though this could change in a future 1011 ** release of SQLite. 1012 ** With SQLITE_ACCESS_READ, the xAccess method 1013 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1014 ** currently unused, though it might be used in a future release of 1015 ** SQLite. 1016 */ 1017 #define SQLITE_ACCESS_EXISTS 0 1018 #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1019 #define SQLITE_ACCESS_READ 2 /* Unused */ 1020 1021 /* 1022 ** CAPI3REF: Flags for the xShmLock VFS method 1023 ** 1024 ** These integer constants define the various locking operations 1025 ** allowed by the xShmLock method of [sqlite3_io_methods]. The 1026 ** following are the only legal combinations of flags to the 1027 ** xShmLock method: 1028 ** 1029 ** <ul> 1030 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1031 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1032 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1033 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1034 ** </ul> 1035 ** 1036 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1037 ** was given no the corresponding lock. 1038 ** 1039 ** The xShmLock method can transition between unlocked and SHARED or 1040 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1041 ** and EXCLUSIVE. 1042 */ 1043 #define SQLITE_SHM_UNLOCK 1 1044 #define SQLITE_SHM_LOCK 2 1045 #define SQLITE_SHM_SHARED 4 1046 #define SQLITE_SHM_EXCLUSIVE 8 1047 1048 /* 1049 ** CAPI3REF: Maximum xShmLock index 1050 ** 1051 ** The xShmLock method on [sqlite3_io_methods] may use values 1052 ** between 0 and this upper bound as its "offset" argument. 1053 ** The SQLite core will never attempt to acquire or release a 1054 ** lock outside of this range 1055 */ 1056 #define SQLITE_SHM_NLOCK 8 1057 1058 1059 /* 1060 ** CAPI3REF: Initialize The SQLite Library 1061 ** 1062 ** ^The sqlite3_initialize() routine initializes the 1063 ** SQLite library. ^The sqlite3_shutdown() routine 1064 ** deallocates any resources that were allocated by sqlite3_initialize(). 1065 ** These routines are designed to aid in process initialization and 1066 ** shutdown on embedded systems. Workstation applications using 1067 ** SQLite normally do not need to invoke either of these routines. 1068 ** 1069 ** A call to sqlite3_initialize() is an "effective" call if it is 1070 ** the first time sqlite3_initialize() is invoked during the lifetime of 1071 ** the process, or if it is the first time sqlite3_initialize() is invoked 1072 ** following a call to sqlite3_shutdown(). ^(Only an effective call 1073 ** of sqlite3_initialize() does any initialization. All other calls 1074 ** are harmless no-ops.)^ 1075 ** 1076 ** A call to sqlite3_shutdown() is an "effective" call if it is the first 1077 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1078 ** an effective call to sqlite3_shutdown() does any deinitialization. 1079 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1080 ** 1081 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1082 ** is not. The sqlite3_shutdown() interface must only be called from a 1083 ** single thread. All open [database connections] must be closed and all 1084 ** other SQLite resources must be deallocated prior to invoking 1085 ** sqlite3_shutdown(). 1086 ** 1087 ** Among other things, ^sqlite3_initialize() will invoke 1088 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1089 ** will invoke sqlite3_os_end(). 1090 ** 1091 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1092 ** ^If for some reason, sqlite3_initialize() is unable to initialize 1093 ** the library (perhaps it is unable to allocate a needed resource such 1094 ** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1095 ** 1096 ** ^The sqlite3_initialize() routine is called internally by many other 1097 ** SQLite interfaces so that an application usually does not need to 1098 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1099 ** calls sqlite3_initialize() so the SQLite library will be automatically 1100 ** initialized when [sqlite3_open()] is called if it has not be initialized 1101 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1102 ** compile-time option, then the automatic calls to sqlite3_initialize() 1103 ** are omitted and the application must call sqlite3_initialize() directly 1104 ** prior to using any other SQLite interface. For maximum portability, 1105 ** it is recommended that applications always invoke sqlite3_initialize() 1106 ** directly prior to using any other SQLite interface. Future releases 1107 ** of SQLite may require this. In other words, the behavior exhibited 1108 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1109 ** default behavior in some future release of SQLite. 1110 ** 1111 ** The sqlite3_os_init() routine does operating-system specific 1112 ** initialization of the SQLite library. The sqlite3_os_end() 1113 ** routine undoes the effect of sqlite3_os_init(). Typical tasks 1114 ** performed by these routines include allocation or deallocation 1115 ** of static resources, initialization of global variables, 1116 ** setting up a default [sqlite3_vfs] module, or setting up 1117 ** a default configuration using [sqlite3_config()]. 1118 ** 1119 ** The application should never invoke either sqlite3_os_init() 1120 ** or sqlite3_os_end() directly. The application should only invoke 1121 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1122 ** interface is called automatically by sqlite3_initialize() and 1123 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1124 ** implementations for sqlite3_os_init() and sqlite3_os_end() 1125 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1126 ** When [custom builds | built for other platforms] 1127 ** (using the [SQLITE_OS_OTHER=1] compile-time 1128 ** option) the application must supply a suitable implementation for 1129 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1130 ** implementation of sqlite3_os_init() or sqlite3_os_end() 1131 ** must return [SQLITE_OK] on success and some other [error code] upon 1132 ** failure. 1133 */ 1134 SQLITE_API int sqlite3_initialize(void); 1135 SQLITE_API int sqlite3_shutdown(void); 1136 SQLITE_API int sqlite3_os_init(void); 1137 SQLITE_API int sqlite3_os_end(void); 1138 1139 /* 1140 ** CAPI3REF: Configuring The SQLite Library 1141 ** 1142 ** The sqlite3_config() interface is used to make global configuration 1143 ** changes to SQLite in order to tune SQLite to the specific needs of 1144 ** the application. The default configuration is recommended for most 1145 ** applications and so this routine is usually not necessary. It is 1146 ** provided to support rare applications with unusual needs. 1147 ** 1148 ** The sqlite3_config() interface is not threadsafe. The application 1149 ** must insure that no other SQLite interfaces are invoked by other 1150 ** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1151 ** may only be invoked prior to library initialization using 1152 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1153 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1154 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1155 ** Note, however, that ^sqlite3_config() can be called as part of the 1156 ** implementation of an application-defined [sqlite3_os_init()]. 1157 ** 1158 ** The first argument to sqlite3_config() is an integer 1159 ** [configuration option] that determines 1160 ** what property of SQLite is to be configured. Subsequent arguments 1161 ** vary depending on the [configuration option] 1162 ** in the first argument. 1163 ** 1164 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1165 ** ^If the option is unknown or SQLite is unable to set the option 1166 ** then this routine returns a non-zero [error code]. 1167 */ 1168 SQLITE_API int sqlite3_config(int, ...); 1169 1170 /* 1171 ** CAPI3REF: Configure database connections 1172 ** 1173 ** The sqlite3_db_config() interface is used to make configuration 1174 ** changes to a [database connection]. The interface is similar to 1175 ** [sqlite3_config()] except that the changes apply to a single 1176 ** [database connection] (specified in the first argument). 1177 ** 1178 ** The second argument to sqlite3_db_config(D,V,...) is the 1179 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1180 ** that indicates what aspect of the [database connection] is being configured. 1181 ** Subsequent arguments vary depending on the configuration verb. 1182 ** 1183 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1184 ** the call is considered successful. 1185 */ 1186 SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...); 1187 1188 /* 1189 ** CAPI3REF: Memory Allocation Routines 1190 ** 1191 ** An instance of this object defines the interface between SQLite 1192 ** and low-level memory allocation routines. 1193 ** 1194 ** This object is used in only one place in the SQLite interface. 1195 ** A pointer to an instance of this object is the argument to 1196 ** [sqlite3_config()] when the configuration option is 1197 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1198 ** By creating an instance of this object 1199 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1200 ** during configuration, an application can specify an alternative 1201 ** memory allocation subsystem for SQLite to use for all of its 1202 ** dynamic memory needs. 1203 ** 1204 ** Note that SQLite comes with several [built-in memory allocators] 1205 ** that are perfectly adequate for the overwhelming majority of applications 1206 ** and that this object is only useful to a tiny minority of applications 1207 ** with specialized memory allocation requirements. This object is 1208 ** also used during testing of SQLite in order to specify an alternative 1209 ** memory allocator that simulates memory out-of-memory conditions in 1210 ** order to verify that SQLite recovers gracefully from such 1211 ** conditions. 1212 ** 1213 ** The xMalloc, xRealloc, and xFree methods must work like the 1214 ** malloc(), realloc() and free() functions from the standard C library. 1215 ** ^SQLite guarantees that the second argument to 1216 ** xRealloc is always a value returned by a prior call to xRoundup. 1217 ** 1218 ** xSize should return the allocated size of a memory allocation 1219 ** previously obtained from xMalloc or xRealloc. The allocated size 1220 ** is always at least as big as the requested size but may be larger. 1221 ** 1222 ** The xRoundup method returns what would be the allocated size of 1223 ** a memory allocation given a particular requested size. Most memory 1224 ** allocators round up memory allocations at least to the next multiple 1225 ** of 8. Some allocators round up to a larger multiple or to a power of 2. 1226 ** Every memory allocation request coming in through [sqlite3_malloc()] 1227 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1228 ** that causes the corresponding memory allocation to fail. 1229 ** 1230 ** The xInit method initializes the memory allocator. (For example, 1231 ** it might allocate any require mutexes or initialize internal data 1232 ** structures. The xShutdown method is invoked (indirectly) by 1233 ** [sqlite3_shutdown()] and should deallocate any resources acquired 1234 ** by xInit. The pAppData pointer is used as the only parameter to 1235 ** xInit and xShutdown. 1236 ** 1237 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1238 ** the xInit method, so the xInit method need not be threadsafe. The 1239 ** xShutdown method is only called from [sqlite3_shutdown()] so it does 1240 ** not need to be threadsafe either. For all other methods, SQLite 1241 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1242 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1243 ** it is by default) and so the methods are automatically serialized. 1244 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1245 ** methods must be threadsafe or else make their own arrangements for 1246 ** serialization. 1247 ** 1248 ** SQLite will never invoke xInit() more than once without an intervening 1249 ** call to xShutdown(). 1250 */ 1251 typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1252 struct sqlite3_mem_methods { 1253 void *(*xMalloc)(int); /* Memory allocation function */ 1254 void (*xFree)(void*); /* Free a prior allocation */ 1255 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1256 int (*xSize)(void*); /* Return the size of an allocation */ 1257 int (*xRoundup)(int); /* Round up request size to allocation size */ 1258 int (*xInit)(void*); /* Initialize the memory allocator */ 1259 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1260 void *pAppData; /* Argument to xInit() and xShutdown() */ 1261 }; 1262 1263 /* 1264 ** CAPI3REF: Configuration Options 1265 ** KEYWORDS: {configuration option} 1266 ** 1267 ** These constants are the available integer configuration options that 1268 ** can be passed as the first argument to the [sqlite3_config()] interface. 1269 ** 1270 ** New configuration options may be added in future releases of SQLite. 1271 ** Existing configuration options might be discontinued. Applications 1272 ** should check the return code from [sqlite3_config()] to make sure that 1273 ** the call worked. The [sqlite3_config()] interface will return a 1274 ** non-zero [error code] if a discontinued or unsupported configuration option 1275 ** is invoked. 1276 ** 1277 ** <dl> 1278 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1279 ** <dd>There are no arguments to this option. ^This option sets the 1280 ** [threading mode] to Single-thread. In other words, it disables 1281 ** all mutexing and puts SQLite into a mode where it can only be used 1282 ** by a single thread. ^If SQLite is compiled with 1283 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1284 ** it is not possible to change the [threading mode] from its default 1285 ** value of Single-thread and so [sqlite3_config()] will return 1286 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1287 ** configuration option.</dd> 1288 ** 1289 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1290 ** <dd>There are no arguments to this option. ^This option sets the 1291 ** [threading mode] to Multi-thread. In other words, it disables 1292 ** mutexing on [database connection] and [prepared statement] objects. 1293 ** The application is responsible for serializing access to 1294 ** [database connections] and [prepared statements]. But other mutexes 1295 ** are enabled so that SQLite will be safe to use in a multi-threaded 1296 ** environment as long as no two threads attempt to use the same 1297 ** [database connection] at the same time. ^If SQLite is compiled with 1298 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1299 ** it is not possible to set the Multi-thread [threading mode] and 1300 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1301 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1302 ** 1303 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1304 ** <dd>There are no arguments to this option. ^This option sets the 1305 ** [threading mode] to Serialized. In other words, this option enables 1306 ** all mutexes including the recursive 1307 ** mutexes on [database connection] and [prepared statement] objects. 1308 ** In this mode (which is the default when SQLite is compiled with 1309 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1310 ** to [database connections] and [prepared statements] so that the 1311 ** application is free to use the same [database connection] or the 1312 ** same [prepared statement] in different threads at the same time. 1313 ** ^If SQLite is compiled with 1314 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1315 ** it is not possible to set the Serialized [threading mode] and 1316 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1317 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1318 ** 1319 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1320 ** <dd> ^(This option takes a single argument which is a pointer to an 1321 ** instance of the [sqlite3_mem_methods] structure. The argument specifies 1322 ** alternative low-level memory allocation routines to be used in place of 1323 ** the memory allocation routines built into SQLite.)^ ^SQLite makes 1324 ** its own private copy of the content of the [sqlite3_mem_methods] structure 1325 ** before the [sqlite3_config()] call returns.</dd> 1326 ** 1327 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1328 ** <dd> ^(This option takes a single argument which is a pointer to an 1329 ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1330 ** structure is filled with the currently defined memory allocation routines.)^ 1331 ** This option can be used to overload the default memory allocation 1332 ** routines with a wrapper that simulations memory allocation failure or 1333 ** tracks memory usage, for example. </dd> 1334 ** 1335 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1336 ** <dd> ^This option takes single argument of type int, interpreted as a 1337 ** boolean, which enables or disables the collection of memory allocation 1338 ** statistics. ^(When memory allocation statistics are disabled, the 1339 ** following SQLite interfaces become non-operational: 1340 ** <ul> 1341 ** <li> [sqlite3_memory_used()] 1342 ** <li> [sqlite3_memory_highwater()] 1343 ** <li> [sqlite3_soft_heap_limit64()] 1344 ** <li> [sqlite3_status()] 1345 ** </ul>)^ 1346 ** ^Memory allocation statistics are enabled by default unless SQLite is 1347 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1348 ** allocation statistics are disabled by default. 1349 ** </dd> 1350 ** 1351 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1352 ** <dd> ^This option specifies a static memory buffer that SQLite can use for 1353 ** scratch memory. There are three arguments: A pointer an 8-byte 1354 ** aligned memory buffer from which the scratch allocations will be 1355 ** drawn, the size of each scratch allocation (sz), 1356 ** and the maximum number of scratch allocations (N). The sz 1357 ** argument must be a multiple of 16. 1358 ** The first argument must be a pointer to an 8-byte aligned buffer 1359 ** of at least sz*N bytes of memory. 1360 ** ^SQLite will use no more than two scratch buffers per thread. So 1361 ** N should be set to twice the expected maximum number of threads. 1362 ** ^SQLite will never require a scratch buffer that is more than 6 1363 ** times the database page size. ^If SQLite needs needs additional 1364 ** scratch memory beyond what is provided by this configuration option, then 1365 ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1366 ** 1367 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1368 ** <dd> ^This option specifies a static memory buffer that SQLite can use for 1369 ** the database page cache with the default page cache implementation. 1370 ** This configuration should not be used if an application-define page 1371 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option. 1372 ** There are three arguments to this option: A pointer to 8-byte aligned 1373 ** memory, the size of each page buffer (sz), and the number of pages (N). 1374 ** The sz argument should be the size of the largest database page 1375 ** (a power of two between 512 and 32768) plus a little extra for each 1376 ** page header. ^The page header size is 20 to 40 bytes depending on 1377 ** the host architecture. ^It is harmless, apart from the wasted memory, 1378 ** to make sz a little too large. The first 1379 ** argument should point to an allocation of at least sz*N bytes of memory. 1380 ** ^SQLite will use the memory provided by the first argument to satisfy its 1381 ** memory needs for the first N pages that it adds to cache. ^If additional 1382 ** page cache memory is needed beyond what is provided by this option, then 1383 ** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1384 ** The pointer in the first argument must 1385 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1386 ** will be undefined.</dd> 1387 ** 1388 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1389 ** <dd> ^This option specifies a static memory buffer that SQLite will use 1390 ** for all of its dynamic memory allocation needs beyond those provided 1391 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1392 ** There are three arguments: An 8-byte aligned pointer to the memory, 1393 ** the number of bytes in the memory buffer, and the minimum allocation size. 1394 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1395 ** to using its default memory allocator (the system malloc() implementation), 1396 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1397 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1398 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1399 ** allocator is engaged to handle all of SQLites memory allocation needs. 1400 ** The first pointer (the memory pointer) must be aligned to an 8-byte 1401 ** boundary or subsequent behavior of SQLite will be undefined. 1402 ** The minimum allocation size is capped at 2^12. Reasonable values 1403 ** for the minimum allocation size are 2^5 through 2^8.</dd> 1404 ** 1405 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1406 ** <dd> ^(This option takes a single argument which is a pointer to an 1407 ** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1408 ** alternative low-level mutex routines to be used in place 1409 ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1410 ** content of the [sqlite3_mutex_methods] structure before the call to 1411 ** [sqlite3_config()] returns. ^If SQLite is compiled with 1412 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1413 ** the entire mutexing subsystem is omitted from the build and hence calls to 1414 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1415 ** return [SQLITE_ERROR].</dd> 1416 ** 1417 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1418 ** <dd> ^(This option takes a single argument which is a pointer to an 1419 ** instance of the [sqlite3_mutex_methods] structure. The 1420 ** [sqlite3_mutex_methods] 1421 ** structure is filled with the currently defined mutex routines.)^ 1422 ** This option can be used to overload the default mutex allocation 1423 ** routines with a wrapper used to track mutex usage for performance 1424 ** profiling or testing, for example. ^If SQLite is compiled with 1425 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1426 ** the entire mutexing subsystem is omitted from the build and hence calls to 1427 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1428 ** return [SQLITE_ERROR].</dd> 1429 ** 1430 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1431 ** <dd> ^(This option takes two arguments that determine the default 1432 ** memory allocation for the lookaside memory allocator on each 1433 ** [database connection]. The first argument is the 1434 ** size of each lookaside buffer slot and the second is the number of 1435 ** slots allocated to each database connection.)^ ^(This option sets the 1436 ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1437 ** verb to [sqlite3_db_config()] can be used to change the lookaside 1438 ** configuration on individual connections.)^ </dd> 1439 ** 1440 ** [[SQLITE_CONFIG_PCACHE]] <dt>SQLITE_CONFIG_PCACHE</dt> 1441 ** <dd> ^(This option takes a single argument which is a pointer to 1442 ** an [sqlite3_pcache_methods] object. This object specifies the interface 1443 ** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1444 ** object and uses it for page cache memory allocations.</dd> 1445 ** 1446 ** [[SQLITE_CONFIG_GETPCACHE]] <dt>SQLITE_CONFIG_GETPCACHE</dt> 1447 ** <dd> ^(This option takes a single argument which is a pointer to an 1448 ** [sqlite3_pcache_methods] object. SQLite copies of the current 1449 ** page cache implementation into that object.)^ </dd> 1450 ** 1451 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1452 ** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1453 ** function with a call signature of void(*)(void*,int,const char*), 1454 ** and a pointer to void. ^If the function pointer is not NULL, it is 1455 ** invoked by [sqlite3_log()] to process each logging event. ^If the 1456 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1457 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1458 ** passed through as the first parameter to the application-defined logger 1459 ** function whenever that function is invoked. ^The second parameter to 1460 ** the logger function is a copy of the first parameter to the corresponding 1461 ** [sqlite3_log()] call and is intended to be a [result code] or an 1462 ** [extended result code]. ^The third parameter passed to the logger is 1463 ** log message after formatting via [sqlite3_snprintf()]. 1464 ** The SQLite logging interface is not reentrant; the logger function 1465 ** supplied by the application must not invoke any SQLite interface. 1466 ** In a multi-threaded application, the application-defined logger 1467 ** function must be threadsafe. </dd> 1468 ** 1469 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1470 ** <dd> This option takes a single argument of type int. If non-zero, then 1471 ** URI handling is globally enabled. If the parameter is zero, then URI handling 1472 ** is globally disabled. If URI handling is globally enabled, all filenames 1473 ** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or 1474 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1475 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1476 ** connection is opened. If it is globally disabled, filenames are 1477 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1478 ** database connection is opened. By default, URI handling is globally 1479 ** disabled. The default value may be changed by compiling with the 1480 ** [SQLITE_USE_URI] symbol defined. 1481 ** </dl> 1482 */ 1483 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1484 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1485 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1486 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1487 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1488 #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1489 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1490 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1491 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1492 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1493 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1494 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1495 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1496 #define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */ 1497 #define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */ 1498 #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1499 #define SQLITE_CONFIG_URI 17 /* int */ 1500 1501 /* 1502 ** CAPI3REF: Database Connection Configuration Options 1503 ** 1504 ** These constants are the available integer configuration options that 1505 ** can be passed as the second argument to the [sqlite3_db_config()] interface. 1506 ** 1507 ** New configuration options may be added in future releases of SQLite. 1508 ** Existing configuration options might be discontinued. Applications 1509 ** should check the return code from [sqlite3_db_config()] to make sure that 1510 ** the call worked. ^The [sqlite3_db_config()] interface will return a 1511 ** non-zero [error code] if a discontinued or unsupported configuration option 1512 ** is invoked. 1513 ** 1514 ** <dl> 1515 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1516 ** <dd> ^This option takes three additional arguments that determine the 1517 ** [lookaside memory allocator] configuration for the [database connection]. 1518 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1519 ** pointer to a memory buffer to use for lookaside memory. 1520 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1521 ** may be NULL in which case SQLite will allocate the 1522 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1523 ** size of each lookaside buffer slot. ^The third argument is the number of 1524 ** slots. The size of the buffer in the first argument must be greater than 1525 ** or equal to the product of the second and third arguments. The buffer 1526 ** must be aligned to an 8-byte boundary. ^If the second argument to 1527 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1528 ** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1529 ** configuration for a database connection can only be changed when that 1530 ** connection is not currently using lookaside memory, or in other words 1531 ** when the "current value" returned by 1532 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1533 ** Any attempt to change the lookaside memory configuration when lookaside 1534 ** memory is in use leaves the configuration unchanged and returns 1535 ** [SQLITE_BUSY].)^</dd> 1536 ** 1537 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1538 ** <dd> ^This option is used to enable or disable the enforcement of 1539 ** [foreign key constraints]. There should be two additional arguments. 1540 ** The first argument is an integer which is 0 to disable FK enforcement, 1541 ** positive to enable FK enforcement or negative to leave FK enforcement 1542 ** unchanged. The second parameter is a pointer to an integer into which 1543 ** is written 0 or 1 to indicate whether FK enforcement is off or on 1544 ** following this call. The second parameter may be a NULL pointer, in 1545 ** which case the FK enforcement setting is not reported back. </dd> 1546 ** 1547 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1548 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1549 ** There should be two additional arguments. 1550 ** The first argument is an integer which is 0 to disable triggers, 1551 ** positive to enable triggers or negative to leave the setting unchanged. 1552 ** The second parameter is a pointer to an integer into which 1553 ** is written 0 or 1 to indicate whether triggers are disabled or enabled 1554 ** following this call. The second parameter may be a NULL pointer, in 1555 ** which case the trigger setting is not reported back. </dd> 1556 ** 1557 ** </dl> 1558 */ 1559 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1560 #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1561 #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1562 1563 1564 /* 1565 ** CAPI3REF: Enable Or Disable Extended Result Codes 1566 ** 1567 ** ^The sqlite3_extended_result_codes() routine enables or disables the 1568 ** [extended result codes] feature of SQLite. ^The extended result 1569 ** codes are disabled by default for historical compatibility. 1570 */ 1571 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff); 1572 1573 /* 1574 ** CAPI3REF: Last Insert Rowid 1575 ** 1576 ** ^Each entry in an SQLite table has a unique 64-bit signed 1577 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1578 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1579 ** names are not also used by explicitly declared columns. ^If 1580 ** the table has a column of type [INTEGER PRIMARY KEY] then that column 1581 ** is another alias for the rowid. 1582 ** 1583 ** ^This routine returns the [rowid] of the most recent 1584 ** successful [INSERT] into the database from the [database connection] 1585 ** in the first argument. ^As of SQLite version 3.7.7, this routines 1586 ** records the last insert rowid of both ordinary tables and [virtual tables]. 1587 ** ^If no successful [INSERT]s 1588 ** have ever occurred on that database connection, zero is returned. 1589 ** 1590 ** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1591 ** method, then this routine will return the [rowid] of the inserted 1592 ** row as long as the trigger or virtual table method is running. 1593 ** But once the trigger or virtual table method ends, the value returned 1594 ** by this routine reverts to what it was before the trigger or virtual 1595 ** table method began.)^ 1596 ** 1597 ** ^An [INSERT] that fails due to a constraint violation is not a 1598 ** successful [INSERT] and does not change the value returned by this 1599 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1600 ** and INSERT OR ABORT make no changes to the return value of this 1601 ** routine when their insertion fails. ^(When INSERT OR REPLACE 1602 ** encounters a constraint violation, it does not fail. The 1603 ** INSERT continues to completion after deleting rows that caused 1604 ** the constraint problem so INSERT OR REPLACE will always change 1605 ** the return value of this interface.)^ 1606 ** 1607 ** ^For the purposes of this routine, an [INSERT] is considered to 1608 ** be successful even if it is subsequently rolled back. 1609 ** 1610 ** This function is accessible to SQL statements via the 1611 ** [last_insert_rowid() SQL function]. 1612 ** 1613 ** If a separate thread performs a new [INSERT] on the same 1614 ** database connection while the [sqlite3_last_insert_rowid()] 1615 ** function is running and thus changes the last insert [rowid], 1616 ** then the value returned by [sqlite3_last_insert_rowid()] is 1617 ** unpredictable and might not equal either the old or the new 1618 ** last insert [rowid]. 1619 */ 1620 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1621 1622 /* 1623 ** CAPI3REF: Count The Number Of Rows Modified 1624 ** 1625 ** ^This function returns the number of database rows that were changed 1626 ** or inserted or deleted by the most recently completed SQL statement 1627 ** on the [database connection] specified by the first parameter. 1628 ** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1629 ** or [DELETE] statement are counted. Auxiliary changes caused by 1630 ** triggers or [foreign key actions] are not counted.)^ Use the 1631 ** [sqlite3_total_changes()] function to find the total number of changes 1632 ** including changes caused by triggers and foreign key actions. 1633 ** 1634 ** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1635 ** are not counted. Only real table changes are counted. 1636 ** 1637 ** ^(A "row change" is a change to a single row of a single table 1638 ** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1639 ** are changed as side effects of [REPLACE] constraint resolution, 1640 ** rollback, ABORT processing, [DROP TABLE], or by any other 1641 ** mechanisms do not count as direct row changes.)^ 1642 ** 1643 ** A "trigger context" is a scope of execution that begins and 1644 ** ends with the script of a [CREATE TRIGGER | trigger]. 1645 ** Most SQL statements are 1646 ** evaluated outside of any trigger. This is the "top level" 1647 ** trigger context. If a trigger fires from the top level, a 1648 ** new trigger context is entered for the duration of that one 1649 ** trigger. Subtriggers create subcontexts for their duration. 1650 ** 1651 ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1652 ** not create a new trigger context. 1653 ** 1654 ** ^This function returns the number of direct row changes in the 1655 ** most recent INSERT, UPDATE, or DELETE statement within the same 1656 ** trigger context. 1657 ** 1658 ** ^Thus, when called from the top level, this function returns the 1659 ** number of changes in the most recent INSERT, UPDATE, or DELETE 1660 ** that also occurred at the top level. ^(Within the body of a trigger, 1661 ** the sqlite3_changes() interface can be called to find the number of 1662 ** changes in the most recently completed INSERT, UPDATE, or DELETE 1663 ** statement within the body of the same trigger. 1664 ** However, the number returned does not include changes 1665 ** caused by subtriggers since those have their own context.)^ 1666 ** 1667 ** See also the [sqlite3_total_changes()] interface, the 1668 ** [count_changes pragma], and the [changes() SQL function]. 1669 ** 1670 ** If a separate thread makes changes on the same database connection 1671 ** while [sqlite3_changes()] is running then the value returned 1672 ** is unpredictable and not meaningful. 1673 */ 1674 SQLITE_API int sqlite3_changes(sqlite3*); 1675 1676 /* 1677 ** CAPI3REF: Total Number Of Rows Modified 1678 ** 1679 ** ^This function returns the number of row changes caused by [INSERT], 1680 ** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1681 ** ^(The count returned by sqlite3_total_changes() includes all changes 1682 ** from all [CREATE TRIGGER | trigger] contexts and changes made by 1683 ** [foreign key actions]. However, 1684 ** the count does not include changes used to implement [REPLACE] constraints, 1685 ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1686 ** count does not include rows of views that fire an [INSTEAD OF trigger], 1687 ** though if the INSTEAD OF trigger makes changes of its own, those changes 1688 ** are counted.)^ 1689 ** ^The sqlite3_total_changes() function counts the changes as soon as 1690 ** the statement that makes them is completed (when the statement handle 1691 ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1692 ** 1693 ** See also the [sqlite3_changes()] interface, the 1694 ** [count_changes pragma], and the [total_changes() SQL function]. 1695 ** 1696 ** If a separate thread makes changes on the same database connection 1697 ** while [sqlite3_total_changes()] is running then the value 1698 ** returned is unpredictable and not meaningful. 1699 */ 1700 SQLITE_API int sqlite3_total_changes(sqlite3*); 1701 1702 /* 1703 ** CAPI3REF: Interrupt A Long-Running Query 1704 ** 1705 ** ^This function causes any pending database operation to abort and 1706 ** return at its earliest opportunity. This routine is typically 1707 ** called in response to a user action such as pressing "Cancel" 1708 ** or Ctrl-C where the user wants a long query operation to halt 1709 ** immediately. 1710 ** 1711 ** ^It is safe to call this routine from a thread different from the 1712 ** thread that is currently running the database operation. But it 1713 ** is not safe to call this routine with a [database connection] that 1714 ** is closed or might close before sqlite3_interrupt() returns. 1715 ** 1716 ** ^If an SQL operation is very nearly finished at the time when 1717 ** sqlite3_interrupt() is called, then it might not have an opportunity 1718 ** to be interrupted and might continue to completion. 1719 ** 1720 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1721 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1722 ** that is inside an explicit transaction, then the entire transaction 1723 ** will be rolled back automatically. 1724 ** 1725 ** ^The sqlite3_interrupt(D) call is in effect until all currently running 1726 ** SQL statements on [database connection] D complete. ^Any new SQL statements 1727 ** that are started after the sqlite3_interrupt() call and before the 1728 ** running statements reaches zero are interrupted as if they had been 1729 ** running prior to the sqlite3_interrupt() call. ^New SQL statements 1730 ** that are started after the running statement count reaches zero are 1731 ** not effected by the sqlite3_interrupt(). 1732 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1733 ** SQL statements is a no-op and has no effect on SQL statements 1734 ** that are started after the sqlite3_interrupt() call returns. 1735 ** 1736 ** If the database connection closes while [sqlite3_interrupt()] 1737 ** is running then bad things will likely happen. 1738 */ 1739 SQLITE_API void sqlite3_interrupt(sqlite3*); 1740 1741 /* 1742 ** CAPI3REF: Determine If An SQL Statement Is Complete 1743 ** 1744 ** These routines are useful during command-line input to determine if the 1745 ** currently entered text seems to form a complete SQL statement or 1746 ** if additional input is needed before sending the text into 1747 ** SQLite for parsing. ^These routines return 1 if the input string 1748 ** appears to be a complete SQL statement. ^A statement is judged to be 1749 ** complete if it ends with a semicolon token and is not a prefix of a 1750 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1751 ** string literals or quoted identifier names or comments are not 1752 ** independent tokens (they are part of the token in which they are 1753 ** embedded) and thus do not count as a statement terminator. ^Whitespace 1754 ** and comments that follow the final semicolon are ignored. 1755 ** 1756 ** ^These routines return 0 if the statement is incomplete. ^If a 1757 ** memory allocation fails, then SQLITE_NOMEM is returned. 1758 ** 1759 ** ^These routines do not parse the SQL statements thus 1760 ** will not detect syntactically incorrect SQL. 1761 ** 1762 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1763 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1764 ** automatically by sqlite3_complete16(). If that initialization fails, 1765 ** then the return value from sqlite3_complete16() will be non-zero 1766 ** regardless of whether or not the input SQL is complete.)^ 1767 ** 1768 ** The input to [sqlite3_complete()] must be a zero-terminated 1769 ** UTF-8 string. 1770 ** 1771 ** The input to [sqlite3_complete16()] must be a zero-terminated 1772 ** UTF-16 string in native byte order. 1773 */ 1774 SQLITE_API int sqlite3_complete(const char *sql); 1775 SQLITE_API int sqlite3_complete16(const void *sql); 1776 1777 /* 1778 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1779 ** 1780 ** ^This routine sets a callback function that might be invoked whenever 1781 ** an attempt is made to open a database table that another thread 1782 ** or process has locked. 1783 ** 1784 ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1785 ** is returned immediately upon encountering the lock. ^If the busy callback 1786 ** is not NULL, then the callback might be invoked with two arguments. 1787 ** 1788 ** ^The first argument to the busy handler is a copy of the void* pointer which 1789 ** is the third argument to sqlite3_busy_handler(). ^The second argument to 1790 ** the busy handler callback is the number of times that the busy handler has 1791 ** been invoked for this locking event. ^If the 1792 ** busy callback returns 0, then no additional attempts are made to 1793 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1794 ** ^If the callback returns non-zero, then another attempt 1795 ** is made to open the database for reading and the cycle repeats. 1796 ** 1797 ** The presence of a busy handler does not guarantee that it will be invoked 1798 ** when there is lock contention. ^If SQLite determines that invoking the busy 1799 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1800 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1801 ** Consider a scenario where one process is holding a read lock that 1802 ** it is trying to promote to a reserved lock and 1803 ** a second process is holding a reserved lock that it is trying 1804 ** to promote to an exclusive lock. The first process cannot proceed 1805 ** because it is blocked by the second and the second process cannot 1806 ** proceed because it is blocked by the first. If both processes 1807 ** invoke the busy handlers, neither will make any progress. Therefore, 1808 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1809 ** will induce the first process to release its read lock and allow 1810 ** the second process to proceed. 1811 ** 1812 ** ^The default busy callback is NULL. 1813 ** 1814 ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1815 ** when SQLite is in the middle of a large transaction where all the 1816 ** changes will not fit into the in-memory cache. SQLite will 1817 ** already hold a RESERVED lock on the database file, but it needs 1818 ** to promote this lock to EXCLUSIVE so that it can spill cache 1819 ** pages into the database file without harm to concurrent 1820 ** readers. ^If it is unable to promote the lock, then the in-memory 1821 ** cache will be left in an inconsistent state and so the error 1822 ** code is promoted from the relatively benign [SQLITE_BUSY] to 1823 ** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 1824 ** forces an automatic rollback of the changes. See the 1825 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1826 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1827 ** this is important. 1828 ** 1829 ** ^(There can only be a single busy handler defined for each 1830 ** [database connection]. Setting a new busy handler clears any 1831 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 1832 ** will also set or clear the busy handler. 1833 ** 1834 ** The busy callback should not take any actions which modify the 1835 ** database connection that invoked the busy handler. Any such actions 1836 ** result in undefined behavior. 1837 ** 1838 ** A busy handler must not close the database connection 1839 ** or [prepared statement] that invoked the busy handler. 1840 */ 1841 SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1842 1843 /* 1844 ** CAPI3REF: Set A Busy Timeout 1845 ** 1846 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1847 ** for a specified amount of time when a table is locked. ^The handler 1848 ** will sleep multiple times until at least "ms" milliseconds of sleeping 1849 ** have accumulated. ^After at least "ms" milliseconds of sleeping, 1850 ** the handler returns 0 which causes [sqlite3_step()] to return 1851 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1852 ** 1853 ** ^Calling this routine with an argument less than or equal to zero 1854 ** turns off all busy handlers. 1855 ** 1856 ** ^(There can only be a single busy handler for a particular 1857 ** [database connection] any any given moment. If another busy handler 1858 ** was defined (using [sqlite3_busy_handler()]) prior to calling 1859 ** this routine, that other busy handler is cleared.)^ 1860 */ 1861 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms); 1862 1863 /* 1864 ** CAPI3REF: Convenience Routines For Running Queries 1865 ** 1866 ** This is a legacy interface that is preserved for backwards compatibility. 1867 ** Use of this interface is not recommended. 1868 ** 1869 ** Definition: A <b>result table</b> is memory data structure created by the 1870 ** [sqlite3_get_table()] interface. A result table records the 1871 ** complete query results from one or more queries. 1872 ** 1873 ** The table conceptually has a number of rows and columns. But 1874 ** these numbers are not part of the result table itself. These 1875 ** numbers are obtained separately. Let N be the number of rows 1876 ** and M be the number of columns. 1877 ** 1878 ** A result table is an array of pointers to zero-terminated UTF-8 strings. 1879 ** There are (N+1)*M elements in the array. The first M pointers point 1880 ** to zero-terminated strings that contain the names of the columns. 1881 ** The remaining entries all point to query results. NULL values result 1882 ** in NULL pointers. All other values are in their UTF-8 zero-terminated 1883 ** string representation as returned by [sqlite3_column_text()]. 1884 ** 1885 ** A result table might consist of one or more memory allocations. 1886 ** It is not safe to pass a result table directly to [sqlite3_free()]. 1887 ** A result table should be deallocated using [sqlite3_free_table()]. 1888 ** 1889 ** ^(As an example of the result table format, suppose a query result 1890 ** is as follows: 1891 ** 1892 ** <blockquote><pre> 1893 ** Name | Age 1894 ** ----------------------- 1895 ** Alice | 43 1896 ** Bob | 28 1897 ** Cindy | 21 1898 ** </pre></blockquote> 1899 ** 1900 ** There are two column (M==2) and three rows (N==3). Thus the 1901 ** result table has 8 entries. Suppose the result table is stored 1902 ** in an array names azResult. Then azResult holds this content: 1903 ** 1904 ** <blockquote><pre> 1905 ** azResult[0] = "Name"; 1906 ** azResult[1] = "Age"; 1907 ** azResult[2] = "Alice"; 1908 ** azResult[3] = "43"; 1909 ** azResult[4] = "Bob"; 1910 ** azResult[5] = "28"; 1911 ** azResult[6] = "Cindy"; 1912 ** azResult[7] = "21"; 1913 ** </pre></blockquote>)^ 1914 ** 1915 ** ^The sqlite3_get_table() function evaluates one or more 1916 ** semicolon-separated SQL statements in the zero-terminated UTF-8 1917 ** string of its 2nd parameter and returns a result table to the 1918 ** pointer given in its 3rd parameter. 1919 ** 1920 ** After the application has finished with the result from sqlite3_get_table(), 1921 ** it must pass the result table pointer to sqlite3_free_table() in order to 1922 ** release the memory that was malloced. Because of the way the 1923 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1924 ** function must not try to call [sqlite3_free()] directly. Only 1925 ** [sqlite3_free_table()] is able to release the memory properly and safely. 1926 ** 1927 ** The sqlite3_get_table() interface is implemented as a wrapper around 1928 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 1929 ** to any internal data structures of SQLite. It uses only the public 1930 ** interface defined here. As a consequence, errors that occur in the 1931 ** wrapper layer outside of the internal [sqlite3_exec()] call are not 1932 ** reflected in subsequent calls to [sqlite3_errcode()] or 1933 ** [sqlite3_errmsg()]. 1934 */ 1935 SQLITE_API int sqlite3_get_table( 1936 sqlite3 *db, /* An open database */ 1937 const char *zSql, /* SQL to be evaluated */ 1938 char ***pazResult, /* Results of the query */ 1939 int *pnRow, /* Number of result rows written here */ 1940 int *pnColumn, /* Number of result columns written here */ 1941 char **pzErrmsg /* Error msg written here */ 1942 ); 1943 SQLITE_API void sqlite3_free_table(char **result); 1944 1945 /* 1946 ** CAPI3REF: Formatted String Printing Functions 1947 ** 1948 ** These routines are work-alikes of the "printf()" family of functions 1949 ** from the standard C library. 1950 ** 1951 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 1952 ** results into memory obtained from [sqlite3_malloc()]. 1953 ** The strings returned by these two routines should be 1954 ** released by [sqlite3_free()]. ^Both routines return a 1955 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 1956 ** memory to hold the resulting string. 1957 ** 1958 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 1959 ** the standard C library. The result is written into the 1960 ** buffer supplied as the second parameter whose size is given by 1961 ** the first parameter. Note that the order of the 1962 ** first two parameters is reversed from snprintf().)^ This is an 1963 ** historical accident that cannot be fixed without breaking 1964 ** backwards compatibility. ^(Note also that sqlite3_snprintf() 1965 ** returns a pointer to its buffer instead of the number of 1966 ** characters actually written into the buffer.)^ We admit that 1967 ** the number of characters written would be a more useful return 1968 ** value but we cannot change the implementation of sqlite3_snprintf() 1969 ** now without breaking compatibility. 1970 ** 1971 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 1972 ** guarantees that the buffer is always zero-terminated. ^The first 1973 ** parameter "n" is the total size of the buffer, including space for 1974 ** the zero terminator. So the longest string that can be completely 1975 ** written will be n-1 characters. 1976 ** 1977 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 1978 ** 1979 ** These routines all implement some additional formatting 1980 ** options that are useful for constructing SQL statements. 1981 ** All of the usual printf() formatting options apply. In addition, there 1982 ** is are "%q", "%Q", and "%z" options. 1983 ** 1984 ** ^(The %q option works like %s in that it substitutes a null-terminated 1985 ** string from the argument list. But %q also doubles every '\'' character. 1986 ** %q is designed for use inside a string literal.)^ By doubling each '\'' 1987 ** character it escapes that character and allows it to be inserted into 1988 ** the string. 1989 ** 1990 ** For example, assume the string variable zText contains text as follows: 1991 ** 1992 ** <blockquote><pre> 1993 ** char *zText = "It's a happy day!"; 1994 ** </pre></blockquote> 1995 ** 1996 ** One can use this text in an SQL statement as follows: 1997 ** 1998 ** <blockquote><pre> 1999 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2000 ** sqlite3_exec(db, zSQL, 0, 0, 0); 2001 ** sqlite3_free(zSQL); 2002 ** </pre></blockquote> 2003 ** 2004 ** Because the %q format string is used, the '\'' character in zText 2005 ** is escaped and the SQL generated is as follows: 2006 ** 2007 ** <blockquote><pre> 2008 ** INSERT INTO table1 VALUES('It''s a happy day!') 2009 ** </pre></blockquote> 2010 ** 2011 ** This is correct. Had we used %s instead of %q, the generated SQL 2012 ** would have looked like this: 2013 ** 2014 ** <blockquote><pre> 2015 ** INSERT INTO table1 VALUES('It's a happy day!'); 2016 ** </pre></blockquote> 2017 ** 2018 ** This second example is an SQL syntax error. As a general rule you should 2019 ** always use %q instead of %s when inserting text into a string literal. 2020 ** 2021 ** ^(The %Q option works like %q except it also adds single quotes around 2022 ** the outside of the total string. Additionally, if the parameter in the 2023 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2024 ** single quotes).)^ So, for example, one could say: 2025 ** 2026 ** <blockquote><pre> 2027 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2028 ** sqlite3_exec(db, zSQL, 0, 0, 0); 2029 ** sqlite3_free(zSQL); 2030 ** </pre></blockquote> 2031 ** 2032 ** The code above will render a correct SQL statement in the zSQL 2033 ** variable even if the zText variable is a NULL pointer. 2034 ** 2035 ** ^(The "%z" formatting option works like "%s" but with the 2036 ** addition that after the string has been read and copied into 2037 ** the result, [sqlite3_free()] is called on the input string.)^ 2038 */ 2039 SQLITE_API char *sqlite3_mprintf(const char*,...); 2040 SQLITE_API char *sqlite3_vmprintf(const char*, va_list); 2041 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...); 2042 SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2043 2044 /* 2045 ** CAPI3REF: Memory Allocation Subsystem 2046 ** 2047 ** The SQLite core uses these three routines for all of its own 2048 ** internal memory allocation needs. "Core" in the previous sentence 2049 ** does not include operating-system specific VFS implementation. The 2050 ** Windows VFS uses native malloc() and free() for some operations. 2051 ** 2052 ** ^The sqlite3_malloc() routine returns a pointer to a block 2053 ** of memory at least N bytes in length, where N is the parameter. 2054 ** ^If sqlite3_malloc() is unable to obtain sufficient free 2055 ** memory, it returns a NULL pointer. ^If the parameter N to 2056 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2057 ** a NULL pointer. 2058 ** 2059 ** ^Calling sqlite3_free() with a pointer previously returned 2060 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2061 ** that it might be reused. ^The sqlite3_free() routine is 2062 ** a no-op if is called with a NULL pointer. Passing a NULL pointer 2063 ** to sqlite3_free() is harmless. After being freed, memory 2064 ** should neither be read nor written. Even reading previously freed 2065 ** memory might result in a segmentation fault or other severe error. 2066 ** Memory corruption, a segmentation fault, or other severe error 2067 ** might result if sqlite3_free() is called with a non-NULL pointer that 2068 ** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2069 ** 2070 ** ^(The sqlite3_realloc() interface attempts to resize a 2071 ** prior memory allocation to be at least N bytes, where N is the 2072 ** second parameter. The memory allocation to be resized is the first 2073 ** parameter.)^ ^ If the first parameter to sqlite3_realloc() 2074 ** is a NULL pointer then its behavior is identical to calling 2075 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 2076 ** ^If the second parameter to sqlite3_realloc() is zero or 2077 ** negative then the behavior is exactly the same as calling 2078 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 2079 ** ^sqlite3_realloc() returns a pointer to a memory allocation 2080 ** of at least N bytes in size or NULL if sufficient memory is unavailable. 2081 ** ^If M is the size of the prior allocation, then min(N,M) bytes 2082 ** of the prior allocation are copied into the beginning of buffer returned 2083 ** by sqlite3_realloc() and the prior allocation is freed. 2084 ** ^If sqlite3_realloc() returns NULL, then the prior allocation 2085 ** is not freed. 2086 ** 2087 ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 2088 ** is always aligned to at least an 8 byte boundary, or to a 2089 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2090 ** option is used. 2091 ** 2092 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2093 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2094 ** implementation of these routines to be omitted. That capability 2095 ** is no longer provided. Only built-in memory allocators can be used. 2096 ** 2097 ** The Windows OS interface layer calls 2098 ** the system malloc() and free() directly when converting 2099 ** filenames between the UTF-8 encoding used by SQLite 2100 ** and whatever filename encoding is used by the particular Windows 2101 ** installation. Memory allocation errors are detected, but 2102 ** they are reported back as [SQLITE_CANTOPEN] or 2103 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2104 ** 2105 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2106 ** must be either NULL or else pointers obtained from a prior 2107 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2108 ** not yet been released. 2109 ** 2110 ** The application must not read or write any part of 2111 ** a block of memory after it has been released using 2112 ** [sqlite3_free()] or [sqlite3_realloc()]. 2113 */ 2114 SQLITE_API void *sqlite3_malloc(int); 2115 SQLITE_API void *sqlite3_realloc(void*, int); 2116 SQLITE_API void sqlite3_free(void*); 2117 2118 /* 2119 ** CAPI3REF: Memory Allocator Statistics 2120 ** 2121 ** SQLite provides these two interfaces for reporting on the status 2122 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2123 ** routines, which form the built-in memory allocation subsystem. 2124 ** 2125 ** ^The [sqlite3_memory_used()] routine returns the number of bytes 2126 ** of memory currently outstanding (malloced but not freed). 2127 ** ^The [sqlite3_memory_highwater()] routine returns the maximum 2128 ** value of [sqlite3_memory_used()] since the high-water mark 2129 ** was last reset. ^The values returned by [sqlite3_memory_used()] and 2130 ** [sqlite3_memory_highwater()] include any overhead 2131 ** added by SQLite in its implementation of [sqlite3_malloc()], 2132 ** but not overhead added by the any underlying system library 2133 ** routines that [sqlite3_malloc()] may call. 2134 ** 2135 ** ^The memory high-water mark is reset to the current value of 2136 ** [sqlite3_memory_used()] if and only if the parameter to 2137 ** [sqlite3_memory_highwater()] is true. ^The value returned 2138 ** by [sqlite3_memory_highwater(1)] is the high-water mark 2139 ** prior to the reset. 2140 */ 2141 SQLITE_API sqlite3_int64 sqlite3_memory_used(void); 2142 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2143 2144 /* 2145 ** CAPI3REF: Pseudo-Random Number Generator 2146 ** 2147 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2148 ** select random [ROWID | ROWIDs] when inserting new records into a table that 2149 ** already uses the largest possible [ROWID]. The PRNG is also used for 2150 ** the build-in random() and randomblob() SQL functions. This interface allows 2151 ** applications to access the same PRNG for other purposes. 2152 ** 2153 ** ^A call to this routine stores N bytes of randomness into buffer P. 2154 ** 2155 ** ^The first time this routine is invoked (either internally or by 2156 ** the application) the PRNG is seeded using randomness obtained 2157 ** from the xRandomness method of the default [sqlite3_vfs] object. 2158 ** ^On all subsequent invocations, the pseudo-randomness is generated 2159 ** internally and without recourse to the [sqlite3_vfs] xRandomness 2160 ** method. 2161 */ 2162 SQLITE_API void sqlite3_randomness(int N, void *P); 2163 2164 /* 2165 ** CAPI3REF: Compile-Time Authorization Callbacks 2166 ** 2167 ** ^This routine registers an authorizer callback with a particular 2168 ** [database connection], supplied in the first argument. 2169 ** ^The authorizer callback is invoked as SQL statements are being compiled 2170 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2171 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2172 ** points during the compilation process, as logic is being created 2173 ** to perform various actions, the authorizer callback is invoked to 2174 ** see if those actions are allowed. ^The authorizer callback should 2175 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2176 ** specific action but allow the SQL statement to continue to be 2177 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2178 ** rejected with an error. ^If the authorizer callback returns 2179 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2180 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2181 ** the authorizer will fail with an error message. 2182 ** 2183 ** When the callback returns [SQLITE_OK], that means the operation 2184 ** requested is ok. ^When the callback returns [SQLITE_DENY], the 2185 ** [sqlite3_prepare_v2()] or equivalent call that triggered the 2186 ** authorizer will fail with an error message explaining that 2187 ** access is denied. 2188 ** 2189 ** ^The first parameter to the authorizer callback is a copy of the third 2190 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2191 ** to the callback is an integer [SQLITE_COPY | action code] that specifies 2192 ** the particular action to be authorized. ^The third through sixth parameters 2193 ** to the callback are zero-terminated strings that contain additional 2194 ** details about the action to be authorized. 2195 ** 2196 ** ^If the action code is [SQLITE_READ] 2197 ** and the callback returns [SQLITE_IGNORE] then the 2198 ** [prepared statement] statement is constructed to substitute 2199 ** a NULL value in place of the table column that would have 2200 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2201 ** return can be used to deny an untrusted user access to individual 2202 ** columns of a table. 2203 ** ^If the action code is [SQLITE_DELETE] and the callback returns 2204 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2205 ** [truncate optimization] is disabled and all rows are deleted individually. 2206 ** 2207 ** An authorizer is used when [sqlite3_prepare | preparing] 2208 ** SQL statements from an untrusted source, to ensure that the SQL statements 2209 ** do not try to access data they are not allowed to see, or that they do not 2210 ** try to execute malicious statements that damage the database. For 2211 ** example, an application may allow a user to enter arbitrary 2212 ** SQL queries for evaluation by a database. But the application does 2213 ** not want the user to be able to make arbitrary changes to the 2214 ** database. An authorizer could then be put in place while the 2215 ** user-entered SQL is being [sqlite3_prepare | prepared] that 2216 ** disallows everything except [SELECT] statements. 2217 ** 2218 ** Applications that need to process SQL from untrusted sources 2219 ** might also consider lowering resource limits using [sqlite3_limit()] 2220 ** and limiting database size using the [max_page_count] [PRAGMA] 2221 ** in addition to using an authorizer. 2222 ** 2223 ** ^(Only a single authorizer can be in place on a database connection 2224 ** at a time. Each call to sqlite3_set_authorizer overrides the 2225 ** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2226 ** The authorizer is disabled by default. 2227 ** 2228 ** The authorizer callback must not do anything that will modify 2229 ** the database connection that invoked the authorizer callback. 2230 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2231 ** database connections for the meaning of "modify" in this paragraph. 2232 ** 2233 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2234 ** statement might be re-prepared during [sqlite3_step()] due to a 2235 ** schema change. Hence, the application should ensure that the 2236 ** correct authorizer callback remains in place during the [sqlite3_step()]. 2237 ** 2238 ** ^Note that the authorizer callback is invoked only during 2239 ** [sqlite3_prepare()] or its variants. Authorization is not 2240 ** performed during statement evaluation in [sqlite3_step()], unless 2241 ** as stated in the previous paragraph, sqlite3_step() invokes 2242 ** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2243 */ 2244 SQLITE_API int sqlite3_set_authorizer( 2245 sqlite3*, 2246 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2247 void *pUserData 2248 ); 2249 2250 /* 2251 ** CAPI3REF: Authorizer Return Codes 2252 ** 2253 ** The [sqlite3_set_authorizer | authorizer callback function] must 2254 ** return either [SQLITE_OK] or one of these two constants in order 2255 ** to signal SQLite whether or not the action is permitted. See the 2256 ** [sqlite3_set_authorizer | authorizer documentation] for additional 2257 ** information. 2258 ** 2259 ** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code] 2260 ** from the [sqlite3_vtab_on_conflict()] interface. 2261 */ 2262 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2263 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2264 2265 /* 2266 ** CAPI3REF: Authorizer Action Codes 2267 ** 2268 ** The [sqlite3_set_authorizer()] interface registers a callback function 2269 ** that is invoked to authorize certain SQL statement actions. The 2270 ** second parameter to the callback is an integer code that specifies 2271 ** what action is being authorized. These are the integer action codes that 2272 ** the authorizer callback may be passed. 2273 ** 2274 ** These action code values signify what kind of operation is to be 2275 ** authorized. The 3rd and 4th parameters to the authorization 2276 ** callback function will be parameters or NULL depending on which of these 2277 ** codes is used as the second parameter. ^(The 5th parameter to the 2278 ** authorizer callback is the name of the database ("main", "temp", 2279 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2280 ** is the name of the inner-most trigger or view that is responsible for 2281 ** the access attempt or NULL if this access attempt is directly from 2282 ** top-level SQL code. 2283 */ 2284 /******************************************* 3rd ************ 4th ***********/ 2285 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2286 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2287 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2288 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2289 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2290 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2291 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2292 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2293 #define SQLITE_DELETE 9 /* Table Name NULL */ 2294 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2295 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2296 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2297 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2298 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2299 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2300 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2301 #define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2302 #define SQLITE_INSERT 18 /* Table Name NULL */ 2303 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2304 #define SQLITE_READ 20 /* Table Name Column Name */ 2305 #define SQLITE_SELECT 21 /* NULL NULL */ 2306 #define SQLITE_TRANSACTION 22 /* Operation NULL */ 2307 #define SQLITE_UPDATE 23 /* Table Name Column Name */ 2308 #define SQLITE_ATTACH 24 /* Filename NULL */ 2309 #define SQLITE_DETACH 25 /* Database Name NULL */ 2310 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2311 #define SQLITE_REINDEX 27 /* Index Name NULL */ 2312 #define SQLITE_ANALYZE 28 /* Table Name NULL */ 2313 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2314 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2315 #define SQLITE_FUNCTION 31 /* NULL Function Name */ 2316 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2317 #define SQLITE_COPY 0 /* No longer used */ 2318 2319 /* 2320 ** CAPI3REF: Tracing And Profiling Functions 2321 ** 2322 ** These routines register callback functions that can be used for 2323 ** tracing and profiling the execution of SQL statements. 2324 ** 2325 ** ^The callback function registered by sqlite3_trace() is invoked at 2326 ** various times when an SQL statement is being run by [sqlite3_step()]. 2327 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2328 ** SQL statement text as the statement first begins executing. 2329 ** ^(Additional sqlite3_trace() callbacks might occur 2330 ** as each triggered subprogram is entered. The callbacks for triggers 2331 ** contain a UTF-8 SQL comment that identifies the trigger.)^ 2332 ** 2333 ** ^The callback function registered by sqlite3_profile() is invoked 2334 ** as each SQL statement finishes. ^The profile callback contains 2335 ** the original statement text and an estimate of wall-clock time 2336 ** of how long that statement took to run. ^The profile callback 2337 ** time is in units of nanoseconds, however the current implementation 2338 ** is only capable of millisecond resolution so the six least significant 2339 ** digits in the time are meaningless. Future versions of SQLite 2340 ** might provide greater resolution on the profiler callback. The 2341 ** sqlite3_profile() function is considered experimental and is 2342 ** subject to change in future versions of SQLite. 2343 */ 2344 SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2345 SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2346 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2347 2348 /* 2349 ** CAPI3REF: Query Progress Callbacks 2350 ** 2351 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2352 ** function X to be invoked periodically during long running calls to 2353 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2354 ** database connection D. An example use for this 2355 ** interface is to keep a GUI updated during a large query. 2356 ** 2357 ** ^The parameter P is passed through as the only parameter to the 2358 ** callback function X. ^The parameter N is the number of 2359 ** [virtual machine instructions] that are evaluated between successive 2360 ** invocations of the callback X. 2361 ** 2362 ** ^Only a single progress handler may be defined at one time per 2363 ** [database connection]; setting a new progress handler cancels the 2364 ** old one. ^Setting parameter X to NULL disables the progress handler. 2365 ** ^The progress handler is also disabled by setting N to a value less 2366 ** than 1. 2367 ** 2368 ** ^If the progress callback returns non-zero, the operation is 2369 ** interrupted. This feature can be used to implement a 2370 ** "Cancel" button on a GUI progress dialog box. 2371 ** 2372 ** The progress handler callback must not do anything that will modify 2373 ** the database connection that invoked the progress handler. 2374 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2375 ** database connections for the meaning of "modify" in this paragraph. 2376 ** 2377 */ 2378 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2379 2380 /* 2381 ** CAPI3REF: Opening A New Database Connection 2382 ** 2383 ** ^These routines open an SQLite database file as specified by the 2384 ** filename argument. ^The filename argument is interpreted as UTF-8 for 2385 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2386 ** order for sqlite3_open16(). ^(A [database connection] handle is usually 2387 ** returned in *ppDb, even if an error occurs. The only exception is that 2388 ** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2389 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2390 ** object.)^ ^(If the database is opened (and/or created) successfully, then 2391 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2392 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2393 ** an English language description of the error following a failure of any 2394 ** of the sqlite3_open() routines. 2395 ** 2396 ** ^The default encoding for the database will be UTF-8 if 2397 ** sqlite3_open() or sqlite3_open_v2() is called and 2398 ** UTF-16 in the native byte order if sqlite3_open16() is used. 2399 ** 2400 ** Whether or not an error occurs when it is opened, resources 2401 ** associated with the [database connection] handle should be released by 2402 ** passing it to [sqlite3_close()] when it is no longer required. 2403 ** 2404 ** The sqlite3_open_v2() interface works like sqlite3_open() 2405 ** except that it accepts two additional parameters for additional control 2406 ** over the new database connection. ^(The flags parameter to 2407 ** sqlite3_open_v2() can take one of 2408 ** the following three values, optionally combined with the 2409 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2410 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2411 ** 2412 ** <dl> 2413 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2414 ** <dd>The database is opened in read-only mode. If the database does not 2415 ** already exist, an error is returned.</dd>)^ 2416 ** 2417 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2418 ** <dd>The database is opened for reading and writing if possible, or reading 2419 ** only if the file is write protected by the operating system. In either 2420 ** case the database must already exist, otherwise an error is returned.</dd>)^ 2421 ** 2422 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2423 ** <dd>The database is opened for reading and writing, and is created if 2424 ** it does not already exist. This is the behavior that is always used for 2425 ** sqlite3_open() and sqlite3_open16().</dd>)^ 2426 ** </dl> 2427 ** 2428 ** If the 3rd parameter to sqlite3_open_v2() is not one of the 2429 ** combinations shown above optionally combined with other 2430 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2431 ** then the behavior is undefined. 2432 ** 2433 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2434 ** opens in the multi-thread [threading mode] as long as the single-thread 2435 ** mode has not been set at compile-time or start-time. ^If the 2436 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2437 ** in the serialized [threading mode] unless single-thread was 2438 ** previously selected at compile-time or start-time. 2439 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2440 ** eligible to use [shared cache mode], regardless of whether or not shared 2441 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2442 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2443 ** participate in [shared cache mode] even if it is enabled. 2444 ** 2445 ** ^The fourth parameter to sqlite3_open_v2() is the name of the 2446 ** [sqlite3_vfs] object that defines the operating system interface that 2447 ** the new database connection should use. ^If the fourth parameter is 2448 ** a NULL pointer then the default [sqlite3_vfs] object is used. 2449 ** 2450 ** ^If the filename is ":memory:", then a private, temporary in-memory database 2451 ** is created for the connection. ^This in-memory database will vanish when 2452 ** the database connection is closed. Future versions of SQLite might 2453 ** make use of additional special filenames that begin with the ":" character. 2454 ** It is recommended that when a database filename actually does begin with 2455 ** a ":" character you should prefix the filename with a pathname such as 2456 ** "./" to avoid ambiguity. 2457 ** 2458 ** ^If the filename is an empty string, then a private, temporary 2459 ** on-disk database will be created. ^This private database will be 2460 ** automatically deleted as soon as the database connection is closed. 2461 ** 2462 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2463 ** 2464 ** ^If [URI filename] interpretation is enabled, and the filename argument 2465 ** begins with "file:", then the filename is interpreted as a URI. ^URI 2466 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2467 ** set in the fourth argument to sqlite3_open_v2(), or if it has 2468 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2469 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2470 ** As of SQLite version 3.7.7, URI filename interpretation is turned off 2471 ** by default, but future releases of SQLite might enable URI filename 2472 ** interpretation by default. See "[URI filenames]" for additional 2473 ** information. 2474 ** 2475 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2476 ** authority, then it must be either an empty string or the string 2477 ** "localhost". ^If the authority is not an empty string or "localhost", an 2478 ** error is returned to the caller. ^The fragment component of a URI, if 2479 ** present, is ignored. 2480 ** 2481 ** ^SQLite uses the path component of the URI as the name of the disk file 2482 ** which contains the database. ^If the path begins with a '/' character, 2483 ** then it is interpreted as an absolute path. ^If the path does not begin 2484 ** with a '/' (meaning that the authority section is omitted from the URI) 2485 ** then the path is interpreted as a relative path. 2486 ** ^On windows, the first component of an absolute path 2487 ** is a drive specification (e.g. "C:"). 2488 ** 2489 ** [[core URI query parameters]] 2490 ** The query component of a URI may contain parameters that are interpreted 2491 ** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2492 ** SQLite interprets the following three query parameters: 2493 ** 2494 ** <ul> 2495 ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2496 ** a VFS object that provides the operating system interface that should 2497 ** be used to access the database file on disk. ^If this option is set to 2498 ** an empty string the default VFS object is used. ^Specifying an unknown 2499 ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2500 ** present, then the VFS specified by the option takes precedence over 2501 ** the value passed as the fourth parameter to sqlite3_open_v2(). 2502 ** 2503 ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw" or 2504 ** "rwc". Attempting to set it to any other value is an error)^. 2505 ** ^If "ro" is specified, then the database is opened for read-only 2506 ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2507 ** third argument to sqlite3_prepare_v2(). ^If the mode option is set to 2508 ** "rw", then the database is opened for read-write (but not create) 2509 ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2510 ** been set. ^Value "rwc" is equivalent to setting both 2511 ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If sqlite3_open_v2() is 2512 ** used, it is an error to specify a value for the mode parameter that is 2513 ** less restrictive than that specified by the flags passed as the third 2514 ** parameter. 2515 ** 2516 ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2517 ** "private". ^Setting it to "shared" is equivalent to setting the 2518 ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2519 ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2520 ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2521 ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2522 ** a URI filename, its value overrides any behaviour requested by setting 2523 ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2524 ** </ul> 2525 ** 2526 ** ^Specifying an unknown parameter in the query component of a URI is not an 2527 ** error. Future versions of SQLite might understand additional query 2528 ** parameters. See "[query parameters with special meaning to SQLite]" for 2529 ** additional information. 2530 ** 2531 ** [[URI filename examples]] <h3>URI filename examples</h3> 2532 ** 2533 ** <table border="1" align=center cellpadding=5> 2534 ** <tr><th> URI filenames <th> Results 2535 ** <tr><td> file:data.db <td> 2536 ** Open the file "data.db" in the current directory. 2537 ** <tr><td> file:/home/fred/data.db<br> 2538 ** file:///home/fred/data.db <br> 2539 ** file://localhost/home/fred/data.db <br> <td> 2540 ** Open the database file "/home/fred/data.db". 2541 ** <tr><td> file://darkstar/home/fred/data.db <td> 2542 ** An error. "darkstar" is not a recognized authority. 2543 ** <tr><td style="white-space:nowrap"> 2544 ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2545 ** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2546 ** C:. Note that the %20 escaping in this example is not strictly 2547 ** necessary - space characters can be used literally 2548 ** in URI filenames. 2549 ** <tr><td> file:data.db?mode=ro&cache=private <td> 2550 ** Open file "data.db" in the current directory for read-only access. 2551 ** Regardless of whether or not shared-cache mode is enabled by 2552 ** default, use a private cache. 2553 ** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td> 2554 ** Open file "/home/fred/data.db". Use the special VFS "unix-nolock". 2555 ** <tr><td> file:data.db?mode=readonly <td> 2556 ** An error. "readonly" is not a valid option for the "mode" parameter. 2557 ** </table> 2558 ** 2559 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2560 ** query components of a URI. A hexadecimal escape sequence consists of a 2561 ** percent sign - "%" - followed by exactly two hexadecimal digits 2562 ** specifying an octet value. ^Before the path or query components of a 2563 ** URI filename are interpreted, they are encoded using UTF-8 and all 2564 ** hexadecimal escape sequences replaced by a single byte containing the 2565 ** corresponding octet. If this process generates an invalid UTF-8 encoding, 2566 ** the results are undefined. 2567 ** 2568 ** <b>Note to Windows users:</b> The encoding used for the filename argument 2569 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2570 ** codepage is currently defined. Filenames containing international 2571 ** characters must be converted to UTF-8 prior to passing them into 2572 ** sqlite3_open() or sqlite3_open_v2(). 2573 */ 2574 SQLITE_API int sqlite3_open( 2575 const char *filename, /* Database filename (UTF-8) */ 2576 sqlite3 **ppDb /* OUT: SQLite db handle */ 2577 ); 2578 SQLITE_API int sqlite3_open16( 2579 const void *filename, /* Database filename (UTF-16) */ 2580 sqlite3 **ppDb /* OUT: SQLite db handle */ 2581 ); 2582 SQLITE_API int sqlite3_open_v2( 2583 const char *filename, /* Database filename (UTF-8) */ 2584 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2585 int flags, /* Flags */ 2586 const char *zVfs /* Name of VFS module to use */ 2587 ); 2588 2589 /* 2590 ** CAPI3REF: Obtain Values For URI Parameters 2591 ** 2592 ** This is a utility routine, useful to VFS implementations, that checks 2593 ** to see if a database file was a URI that contained a specific query 2594 ** parameter, and if so obtains the value of the query parameter. 2595 ** 2596 ** The zFilename argument is the filename pointer passed into the xOpen() 2597 ** method of a VFS implementation. The zParam argument is the name of the 2598 ** query parameter we seek. This routine returns the value of the zParam 2599 ** parameter if it exists. If the parameter does not exist, this routine 2600 ** returns a NULL pointer. 2601 ** 2602 ** If the zFilename argument to this function is not a pointer that SQLite 2603 ** passed into the xOpen VFS method, then the behavior of this routine 2604 ** is undefined and probably undesirable. 2605 */ 2606 SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 2607 2608 2609 /* 2610 ** CAPI3REF: Error Codes And Messages 2611 ** 2612 ** ^The sqlite3_errcode() interface returns the numeric [result code] or 2613 ** [extended result code] for the most recent failed sqlite3_* API call 2614 ** associated with a [database connection]. If a prior API call failed 2615 ** but the most recent API call succeeded, the return value from 2616 ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2617 ** interface is the same except that it always returns the 2618 ** [extended result code] even when extended result codes are 2619 ** disabled. 2620 ** 2621 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2622 ** text that describes the error, as either UTF-8 or UTF-16 respectively. 2623 ** ^(Memory to hold the error message string is managed internally. 2624 ** The application does not need to worry about freeing the result. 2625 ** However, the error string might be overwritten or deallocated by 2626 ** subsequent calls to other SQLite interface functions.)^ 2627 ** 2628 ** When the serialized [threading mode] is in use, it might be the 2629 ** case that a second error occurs on a separate thread in between 2630 ** the time of the first error and the call to these interfaces. 2631 ** When that happens, the second error will be reported since these 2632 ** interfaces always report the most recent result. To avoid 2633 ** this, each thread can obtain exclusive use of the [database connection] D 2634 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2635 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2636 ** all calls to the interfaces listed here are completed. 2637 ** 2638 ** If an interface fails with SQLITE_MISUSE, that means the interface 2639 ** was invoked incorrectly by the application. In that case, the 2640 ** error code and message may or may not be set. 2641 */ 2642 SQLITE_API int sqlite3_errcode(sqlite3 *db); 2643 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db); 2644 SQLITE_API const char *sqlite3_errmsg(sqlite3*); 2645 SQLITE_API const void *sqlite3_errmsg16(sqlite3*); 2646 2647 /* 2648 ** CAPI3REF: SQL Statement Object 2649 ** KEYWORDS: {prepared statement} {prepared statements} 2650 ** 2651 ** An instance of this object represents a single SQL statement. 2652 ** This object is variously known as a "prepared statement" or a 2653 ** "compiled SQL statement" or simply as a "statement". 2654 ** 2655 ** The life of a statement object goes something like this: 2656 ** 2657 ** <ol> 2658 ** <li> Create the object using [sqlite3_prepare_v2()] or a related 2659 ** function. 2660 ** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2661 ** interfaces. 2662 ** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2663 ** <li> Reset the statement using [sqlite3_reset()] then go back 2664 ** to step 2. Do this zero or more times. 2665 ** <li> Destroy the object using [sqlite3_finalize()]. 2666 ** </ol> 2667 ** 2668 ** Refer to documentation on individual methods above for additional 2669 ** information. 2670 */ 2671 typedef struct sqlite3_stmt sqlite3_stmt; 2672 2673 /* 2674 ** CAPI3REF: Run-time Limits 2675 ** 2676 ** ^(This interface allows the size of various constructs to be limited 2677 ** on a connection by connection basis. The first parameter is the 2678 ** [database connection] whose limit is to be set or queried. The 2679 ** second parameter is one of the [limit categories] that define a 2680 ** class of constructs to be size limited. The third parameter is the 2681 ** new limit for that construct.)^ 2682 ** 2683 ** ^If the new limit is a negative number, the limit is unchanged. 2684 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 2685 ** [limits | hard upper bound] 2686 ** set at compile-time by a C preprocessor macro called 2687 ** [limits | SQLITE_MAX_<i>NAME</i>]. 2688 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2689 ** ^Attempts to increase a limit above its hard upper bound are 2690 ** silently truncated to the hard upper bound. 2691 ** 2692 ** ^Regardless of whether or not the limit was changed, the 2693 ** [sqlite3_limit()] interface returns the prior value of the limit. 2694 ** ^Hence, to find the current value of a limit without changing it, 2695 ** simply invoke this interface with the third parameter set to -1. 2696 ** 2697 ** Run-time limits are intended for use in applications that manage 2698 ** both their own internal database and also databases that are controlled 2699 ** by untrusted external sources. An example application might be a 2700 ** web browser that has its own databases for storing history and 2701 ** separate databases controlled by JavaScript applications downloaded 2702 ** off the Internet. The internal databases can be given the 2703 ** large, default limits. Databases managed by external sources can 2704 ** be given much smaller limits designed to prevent a denial of service 2705 ** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2706 ** interface to further control untrusted SQL. The size of the database 2707 ** created by an untrusted script can be contained using the 2708 ** [max_page_count] [PRAGMA]. 2709 ** 2710 ** New run-time limit categories may be added in future releases. 2711 */ 2712 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal); 2713 2714 /* 2715 ** CAPI3REF: Run-Time Limit Categories 2716 ** KEYWORDS: {limit category} {*limit categories} 2717 ** 2718 ** These constants define various performance limits 2719 ** that can be lowered at run-time using [sqlite3_limit()]. 2720 ** The synopsis of the meanings of the various limits is shown below. 2721 ** Additional information is available at [limits | Limits in SQLite]. 2722 ** 2723 ** <dl> 2724 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2725 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 2726 ** 2727 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2728 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2729 ** 2730 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2731 ** <dd>The maximum number of columns in a table definition or in the 2732 ** result set of a [SELECT] or the maximum number of columns in an index 2733 ** or in an ORDER BY or GROUP BY clause.</dd>)^ 2734 ** 2735 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2736 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2737 ** 2738 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2739 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2740 ** 2741 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2742 ** <dd>The maximum number of instructions in a virtual machine program 2743 ** used to implement an SQL statement. This limit is not currently 2744 ** enforced, though that might be added in some future release of 2745 ** SQLite.</dd>)^ 2746 ** 2747 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2748 ** <dd>The maximum number of arguments on a function.</dd>)^ 2749 ** 2750 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2751 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2752 ** 2753 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 2754 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2755 ** <dd>The maximum length of the pattern argument to the [LIKE] or 2756 ** [GLOB] operators.</dd>)^ 2757 ** 2758 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 2759 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2760 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 2761 ** 2762 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2763 ** <dd>The maximum depth of recursion for triggers.</dd>)^ 2764 ** </dl> 2765 */ 2766 #define SQLITE_LIMIT_LENGTH 0 2767 #define SQLITE_LIMIT_SQL_LENGTH 1 2768 #define SQLITE_LIMIT_COLUMN 2 2769 #define SQLITE_LIMIT_EXPR_DEPTH 3 2770 #define SQLITE_LIMIT_COMPOUND_SELECT 4 2771 #define SQLITE_LIMIT_VDBE_OP 5 2772 #define SQLITE_LIMIT_FUNCTION_ARG 6 2773 #define SQLITE_LIMIT_ATTACHED 7 2774 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2775 #define SQLITE_LIMIT_VARIABLE_NUMBER 9 2776 #define SQLITE_LIMIT_TRIGGER_DEPTH 10 2777 2778 /* 2779 ** CAPI3REF: Compiling An SQL Statement 2780 ** KEYWORDS: {SQL statement compiler} 2781 ** 2782 ** To execute an SQL query, it must first be compiled into a byte-code 2783 ** program using one of these routines. 2784 ** 2785 ** The first argument, "db", is a [database connection] obtained from a 2786 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2787 ** [sqlite3_open16()]. The database connection must not have been closed. 2788 ** 2789 ** The second argument, "zSql", is the statement to be compiled, encoded 2790 ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2791 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2792 ** use UTF-16. 2793 ** 2794 ** ^If the nByte argument is less than zero, then zSql is read up to the 2795 ** first zero terminator. ^If nByte is non-negative, then it is the maximum 2796 ** number of bytes read from zSql. ^When nByte is non-negative, the 2797 ** zSql string ends at either the first '\000' or '\u0000' character or 2798 ** the nByte-th byte, whichever comes first. If the caller knows 2799 ** that the supplied string is nul-terminated, then there is a small 2800 ** performance advantage to be gained by passing an nByte parameter that 2801 ** is equal to the number of bytes in the input string <i>including</i> 2802 ** the nul-terminator bytes. 2803 ** 2804 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte 2805 ** past the end of the first SQL statement in zSql. These routines only 2806 ** compile the first statement in zSql, so *pzTail is left pointing to 2807 ** what remains uncompiled. 2808 ** 2809 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 2810 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 2811 ** to NULL. ^If the input text contains no SQL (if the input is an empty 2812 ** string or a comment) then *ppStmt is set to NULL. 2813 ** The calling procedure is responsible for deleting the compiled 2814 ** SQL statement using [sqlite3_finalize()] after it has finished with it. 2815 ** ppStmt may not be NULL. 2816 ** 2817 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 2818 ** otherwise an [error code] is returned. 2819 ** 2820 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2821 ** recommended for all new programs. The two older interfaces are retained 2822 ** for backwards compatibility, but their use is discouraged. 2823 ** ^In the "v2" interfaces, the prepared statement 2824 ** that is returned (the [sqlite3_stmt] object) contains a copy of the 2825 ** original SQL text. This causes the [sqlite3_step()] interface to 2826 ** behave differently in three ways: 2827 ** 2828 ** <ol> 2829 ** <li> 2830 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2831 ** always used to do, [sqlite3_step()] will automatically recompile the SQL 2832 ** statement and try to run it again. 2833 ** </li> 2834 ** 2835 ** <li> 2836 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed 2837 ** [error codes] or [extended error codes]. ^The legacy behavior was that 2838 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2839 ** and the application would have to make a second call to [sqlite3_reset()] 2840 ** in order to find the underlying cause of the problem. With the "v2" prepare 2841 ** interfaces, the underlying reason for the error is returned immediately. 2842 ** </li> 2843 ** 2844 ** <li> 2845 ** ^If the specific value bound to [parameter | host parameter] in the 2846 ** WHERE clause might influence the choice of query plan for a statement, 2847 ** then the statement will be automatically recompiled, as if there had been 2848 ** a schema change, on the first [sqlite3_step()] call following any change 2849 ** to the [sqlite3_bind_text | bindings] of that [parameter]. 2850 ** ^The specific value of WHERE-clause [parameter] might influence the 2851 ** choice of query plan if the parameter is the left-hand side of a [LIKE] 2852 ** or [GLOB] operator or if the parameter is compared to an indexed column 2853 ** and the [SQLITE_ENABLE_STAT2] compile-time option is enabled. 2854 ** the 2855 ** </li> 2856 ** </ol> 2857 */ 2858 SQLITE_API int sqlite3_prepare( 2859 sqlite3 *db, /* Database handle */ 2860 const char *zSql, /* SQL statement, UTF-8 encoded */ 2861 int nByte, /* Maximum length of zSql in bytes. */ 2862 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2863 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2864 ); 2865 SQLITE_API int sqlite3_prepare_v2( 2866 sqlite3 *db, /* Database handle */ 2867 const char *zSql, /* SQL statement, UTF-8 encoded */ 2868 int nByte, /* Maximum length of zSql in bytes. */ 2869 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2870 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2871 ); 2872 SQLITE_API int sqlite3_prepare16( 2873 sqlite3 *db, /* Database handle */ 2874 const void *zSql, /* SQL statement, UTF-16 encoded */ 2875 int nByte, /* Maximum length of zSql in bytes. */ 2876 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2877 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2878 ); 2879 SQLITE_API int sqlite3_prepare16_v2( 2880 sqlite3 *db, /* Database handle */ 2881 const void *zSql, /* SQL statement, UTF-16 encoded */ 2882 int nByte, /* Maximum length of zSql in bytes. */ 2883 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2884 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2885 ); 2886 2887 /* 2888 ** CAPI3REF: Retrieving Statement SQL 2889 ** 2890 ** ^This interface can be used to retrieve a saved copy of the original 2891 ** SQL text used to create a [prepared statement] if that statement was 2892 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2893 */ 2894 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt); 2895 2896 /* 2897 ** CAPI3REF: Determine If An SQL Statement Writes The Database 2898 ** 2899 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 2900 ** and only if the [prepared statement] X makes no direct changes to 2901 ** the content of the database file. 2902 ** 2903 ** Note that [application-defined SQL functions] or 2904 ** [virtual tables] might change the database indirectly as a side effect. 2905 ** ^(For example, if an application defines a function "eval()" that 2906 ** calls [sqlite3_exec()], then the following SQL statement would 2907 ** change the database file through side-effects: 2908 ** 2909 ** <blockquote><pre> 2910 ** SELECT eval('DELETE FROM t1') FROM t2; 2911 ** </pre></blockquote> 2912 ** 2913 ** But because the [SELECT] statement does not change the database file 2914 ** directly, sqlite3_stmt_readonly() would still return true.)^ 2915 ** 2916 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 2917 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 2918 ** since the statements themselves do not actually modify the database but 2919 ** rather they control the timing of when other statements modify the 2920 ** database. ^The [ATTACH] and [DETACH] statements also cause 2921 ** sqlite3_stmt_readonly() to return true since, while those statements 2922 ** change the configuration of a database connection, they do not make 2923 ** changes to the content of the database files on disk. 2924 */ 2925 SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 2926 2927 /* 2928 ** CAPI3REF: Dynamically Typed Value Object 2929 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 2930 ** 2931 ** SQLite uses the sqlite3_value object to represent all values 2932 ** that can be stored in a database table. SQLite uses dynamic typing 2933 ** for the values it stores. ^Values stored in sqlite3_value objects 2934 ** can be integers, floating point values, strings, BLOBs, or NULL. 2935 ** 2936 ** An sqlite3_value object may be either "protected" or "unprotected". 2937 ** Some interfaces require a protected sqlite3_value. Other interfaces 2938 ** will accept either a protected or an unprotected sqlite3_value. 2939 ** Every interface that accepts sqlite3_value arguments specifies 2940 ** whether or not it requires a protected sqlite3_value. 2941 ** 2942 ** The terms "protected" and "unprotected" refer to whether or not 2943 ** a mutex is held. An internal mutex is held for a protected 2944 ** sqlite3_value object but no mutex is held for an unprotected 2945 ** sqlite3_value object. If SQLite is compiled to be single-threaded 2946 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 2947 ** or if SQLite is run in one of reduced mutex modes 2948 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 2949 ** then there is no distinction between protected and unprotected 2950 ** sqlite3_value objects and they can be used interchangeably. However, 2951 ** for maximum code portability it is recommended that applications 2952 ** still make the distinction between protected and unprotected 2953 ** sqlite3_value objects even when not strictly required. 2954 ** 2955 ** ^The sqlite3_value objects that are passed as parameters into the 2956 ** implementation of [application-defined SQL functions] are protected. 2957 ** ^The sqlite3_value object returned by 2958 ** [sqlite3_column_value()] is unprotected. 2959 ** Unprotected sqlite3_value objects may only be used with 2960 ** [sqlite3_result_value()] and [sqlite3_bind_value()]. 2961 ** The [sqlite3_value_blob | sqlite3_value_type()] family of 2962 ** interfaces require protected sqlite3_value objects. 2963 */ 2964 typedef struct Mem sqlite3_value; 2965 2966 /* 2967 ** CAPI3REF: SQL Function Context Object 2968 ** 2969 ** The context in which an SQL function executes is stored in an 2970 ** sqlite3_context object. ^A pointer to an sqlite3_context object 2971 ** is always first parameter to [application-defined SQL functions]. 2972 ** The application-defined SQL function implementation will pass this 2973 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 2974 ** [sqlite3_aggregate_context()], [sqlite3_user_data()], 2975 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 2976 ** and/or [sqlite3_set_auxdata()]. 2977 */ 2978 typedef struct sqlite3_context sqlite3_context; 2979 2980 /* 2981 ** CAPI3REF: Binding Values To Prepared Statements 2982 ** KEYWORDS: {host parameter} {host parameters} {host parameter name} 2983 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 2984 ** 2985 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 2986 ** literals may be replaced by a [parameter] that matches one of following 2987 ** templates: 2988 ** 2989 ** <ul> 2990 ** <li> ? 2991 ** <li> ?NNN 2992 ** <li> :VVV 2993 ** <li> @VVV 2994 ** <li> $VVV 2995 ** </ul> 2996 ** 2997 ** In the templates above, NNN represents an integer literal, 2998 ** and VVV represents an alphanumeric identifier.)^ ^The values of these 2999 ** parameters (also called "host parameter names" or "SQL parameters") 3000 ** can be set using the sqlite3_bind_*() routines defined here. 3001 ** 3002 ** ^The first argument to the sqlite3_bind_*() routines is always 3003 ** a pointer to the [sqlite3_stmt] object returned from 3004 ** [sqlite3_prepare_v2()] or its variants. 3005 ** 3006 ** ^The second argument is the index of the SQL parameter to be set. 3007 ** ^The leftmost SQL parameter has an index of 1. ^When the same named 3008 ** SQL parameter is used more than once, second and subsequent 3009 ** occurrences have the same index as the first occurrence. 3010 ** ^The index for named parameters can be looked up using the 3011 ** [sqlite3_bind_parameter_index()] API if desired. ^The index 3012 ** for "?NNN" parameters is the value of NNN. 3013 ** ^The NNN value must be between 1 and the [sqlite3_limit()] 3014 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3015 ** 3016 ** ^The third argument is the value to bind to the parameter. 3017 ** 3018 ** ^(In those routines that have a fourth argument, its value is the 3019 ** number of bytes in the parameter. To be clear: the value is the 3020 ** number of <u>bytes</u> in the value, not the number of characters.)^ 3021 ** ^If the fourth parameter is negative, the length of the string is 3022 ** the number of bytes up to the first zero terminator. 3023 ** 3024 ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 3025 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 3026 ** string after SQLite has finished with it. ^The destructor is called 3027 ** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(), 3028 ** sqlite3_bind_text(), or sqlite3_bind_text16() fails. 3029 ** ^If the fifth argument is 3030 ** the special value [SQLITE_STATIC], then SQLite assumes that the 3031 ** information is in static, unmanaged space and does not need to be freed. 3032 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3033 ** SQLite makes its own private copy of the data immediately, before 3034 ** the sqlite3_bind_*() routine returns. 3035 ** 3036 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3037 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3038 ** (just an integer to hold its size) while it is being processed. 3039 ** Zeroblobs are intended to serve as placeholders for BLOBs whose 3040 ** content is later written using 3041 ** [sqlite3_blob_open | incremental BLOB I/O] routines. 3042 ** ^A negative value for the zeroblob results in a zero-length BLOB. 3043 ** 3044 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3045 ** for the [prepared statement] or with a prepared statement for which 3046 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3047 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3048 ** routine is passed a [prepared statement] that has been finalized, the 3049 ** result is undefined and probably harmful. 3050 ** 3051 ** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3052 ** ^Unbound parameters are interpreted as NULL. 3053 ** 3054 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3055 ** [error code] if anything goes wrong. 3056 ** ^[SQLITE_RANGE] is returned if the parameter 3057 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3058 ** 3059 ** See also: [sqlite3_bind_parameter_count()], 3060 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3061 */ 3062 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3063 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double); 3064 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int); 3065 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3066 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int); 3067 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 3068 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3069 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3070 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3071 3072 /* 3073 ** CAPI3REF: Number Of SQL Parameters 3074 ** 3075 ** ^This routine can be used to find the number of [SQL parameters] 3076 ** in a [prepared statement]. SQL parameters are tokens of the 3077 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3078 ** placeholders for values that are [sqlite3_bind_blob | bound] 3079 ** to the parameters at a later time. 3080 ** 3081 ** ^(This routine actually returns the index of the largest (rightmost) 3082 ** parameter. For all forms except ?NNN, this will correspond to the 3083 ** number of unique parameters. If parameters of the ?NNN form are used, 3084 ** there may be gaps in the list.)^ 3085 ** 3086 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 3087 ** [sqlite3_bind_parameter_name()], and 3088 ** [sqlite3_bind_parameter_index()]. 3089 */ 3090 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*); 3091 3092 /* 3093 ** CAPI3REF: Name Of A Host Parameter 3094 ** 3095 ** ^The sqlite3_bind_parameter_name(P,N) interface returns 3096 ** the name of the N-th [SQL parameter] in the [prepared statement] P. 3097 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3098 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3099 ** respectively. 3100 ** In other words, the initial ":" or "$" or "@" or "?" 3101 ** is included as part of the name.)^ 3102 ** ^Parameters of the form "?" without a following integer have no name 3103 ** and are referred to as "nameless" or "anonymous parameters". 3104 ** 3105 ** ^The first host parameter has an index of 1, not 0. 3106 ** 3107 ** ^If the value N is out of range or if the N-th parameter is 3108 ** nameless, then NULL is returned. ^The returned string is 3109 ** always in UTF-8 encoding even if the named parameter was 3110 ** originally specified as UTF-16 in [sqlite3_prepare16()] or 3111 ** [sqlite3_prepare16_v2()]. 3112 ** 3113 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 3114 ** [sqlite3_bind_parameter_count()], and 3115 ** [sqlite3_bind_parameter_index()]. 3116 */ 3117 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3118 3119 /* 3120 ** CAPI3REF: Index Of A Parameter With A Given Name 3121 ** 3122 ** ^Return the index of an SQL parameter given its name. ^The 3123 ** index value returned is suitable for use as the second 3124 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3125 ** is returned if no matching parameter is found. ^The parameter 3126 ** name must be given in UTF-8 even if the original statement 3127 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3128 ** 3129 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 3130 ** [sqlite3_bind_parameter_count()], and 3131 ** [sqlite3_bind_parameter_index()]. 3132 */ 3133 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3134 3135 /* 3136 ** CAPI3REF: Reset All Bindings On A Prepared Statement 3137 ** 3138 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3139 ** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3140 ** ^Use this routine to reset all host parameters to NULL. 3141 */ 3142 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*); 3143 3144 /* 3145 ** CAPI3REF: Number Of Columns In A Result Set 3146 ** 3147 ** ^Return the number of columns in the result set returned by the 3148 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3149 ** statement that does not return data (for example an [UPDATE]). 3150 ** 3151 ** See also: [sqlite3_data_count()] 3152 */ 3153 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt); 3154 3155 /* 3156 ** CAPI3REF: Column Names In A Result Set 3157 ** 3158 ** ^These routines return the name assigned to a particular column 3159 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3160 ** interface returns a pointer to a zero-terminated UTF-8 string 3161 ** and sqlite3_column_name16() returns a pointer to a zero-terminated 3162 ** UTF-16 string. ^The first parameter is the [prepared statement] 3163 ** that implements the [SELECT] statement. ^The second parameter is the 3164 ** column number. ^The leftmost column is number 0. 3165 ** 3166 ** ^The returned string pointer is valid until either the [prepared statement] 3167 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3168 ** reprepared by the first call to [sqlite3_step()] for a particular run 3169 ** or until the next call to 3170 ** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3171 ** 3172 ** ^If sqlite3_malloc() fails during the processing of either routine 3173 ** (for example during a conversion from UTF-8 to UTF-16) then a 3174 ** NULL pointer is returned. 3175 ** 3176 ** ^The name of a result column is the value of the "AS" clause for 3177 ** that column, if there is an AS clause. If there is no AS clause 3178 ** then the name of the column is unspecified and may change from 3179 ** one release of SQLite to the next. 3180 */ 3181 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N); 3182 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3183 3184 /* 3185 ** CAPI3REF: Source Of Data In A Query Result 3186 ** 3187 ** ^These routines provide a means to determine the database, table, and 3188 ** table column that is the origin of a particular result column in 3189 ** [SELECT] statement. 3190 ** ^The name of the database or table or column can be returned as 3191 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3192 ** the database name, the _table_ routines return the table name, and 3193 ** the origin_ routines return the column name. 3194 ** ^The returned string is valid until the [prepared statement] is destroyed 3195 ** using [sqlite3_finalize()] or until the statement is automatically 3196 ** reprepared by the first call to [sqlite3_step()] for a particular run 3197 ** or until the same information is requested 3198 ** again in a different encoding. 3199 ** 3200 ** ^The names returned are the original un-aliased names of the 3201 ** database, table, and column. 3202 ** 3203 ** ^The first argument to these interfaces is a [prepared statement]. 3204 ** ^These functions return information about the Nth result column returned by 3205 ** the statement, where N is the second function argument. 3206 ** ^The left-most column is column 0 for these routines. 3207 ** 3208 ** ^If the Nth column returned by the statement is an expression or 3209 ** subquery and is not a column value, then all of these functions return 3210 ** NULL. ^These routine might also return NULL if a memory allocation error 3211 ** occurs. ^Otherwise, they return the name of the attached database, table, 3212 ** or column that query result column was extracted from. 3213 ** 3214 ** ^As with all other SQLite APIs, those whose names end with "16" return 3215 ** UTF-16 encoded strings and the other functions return UTF-8. 3216 ** 3217 ** ^These APIs are only available if the library was compiled with the 3218 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3219 ** 3220 ** If two or more threads call one or more of these routines against the same 3221 ** prepared statement and column at the same time then the results are 3222 ** undefined. 3223 ** 3224 ** If two or more threads call one or more 3225 ** [sqlite3_column_database_name | column metadata interfaces] 3226 ** for the same [prepared statement] and result column 3227 ** at the same time then the results are undefined. 3228 */ 3229 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3230 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3231 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3232 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3233 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3234 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3235 3236 /* 3237 ** CAPI3REF: Declared Datatype Of A Query Result 3238 ** 3239 ** ^(The first parameter is a [prepared statement]. 3240 ** If this statement is a [SELECT] statement and the Nth column of the 3241 ** returned result set of that [SELECT] is a table column (not an 3242 ** expression or subquery) then the declared type of the table 3243 ** column is returned.)^ ^If the Nth column of the result set is an 3244 ** expression or subquery, then a NULL pointer is returned. 3245 ** ^The returned string is always UTF-8 encoded. 3246 ** 3247 ** ^(For example, given the database schema: 3248 ** 3249 ** CREATE TABLE t1(c1 VARIANT); 3250 ** 3251 ** and the following statement to be compiled: 3252 ** 3253 ** SELECT c1 + 1, c1 FROM t1; 3254 ** 3255 ** this routine would return the string "VARIANT" for the second result 3256 ** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3257 ** 3258 ** ^SQLite uses dynamic run-time typing. ^So just because a column 3259 ** is declared to contain a particular type does not mean that the 3260 ** data stored in that column is of the declared type. SQLite is 3261 ** strongly typed, but the typing is dynamic not static. ^Type 3262 ** is associated with individual values, not with the containers 3263 ** used to hold those values. 3264 */ 3265 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3266 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3267 3268 /* 3269 ** CAPI3REF: Evaluate An SQL Statement 3270 ** 3271 ** After a [prepared statement] has been prepared using either 3272 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3273 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3274 ** must be called one or more times to evaluate the statement. 3275 ** 3276 ** The details of the behavior of the sqlite3_step() interface depend 3277 ** on whether the statement was prepared using the newer "v2" interface 3278 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3279 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3280 ** new "v2" interface is recommended for new applications but the legacy 3281 ** interface will continue to be supported. 3282 ** 3283 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3284 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3285 ** ^With the "v2" interface, any of the other [result codes] or 3286 ** [extended result codes] might be returned as well. 3287 ** 3288 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3289 ** database locks it needs to do its job. ^If the statement is a [COMMIT] 3290 ** or occurs outside of an explicit transaction, then you can retry the 3291 ** statement. If the statement is not a [COMMIT] and occurs within an 3292 ** explicit transaction then you should rollback the transaction before 3293 ** continuing. 3294 ** 3295 ** ^[SQLITE_DONE] means that the statement has finished executing 3296 ** successfully. sqlite3_step() should not be called again on this virtual 3297 ** machine without first calling [sqlite3_reset()] to reset the virtual 3298 ** machine back to its initial state. 3299 ** 3300 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3301 ** is returned each time a new row of data is ready for processing by the 3302 ** caller. The values may be accessed using the [column access functions]. 3303 ** sqlite3_step() is called again to retrieve the next row of data. 3304 ** 3305 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3306 ** violation) has occurred. sqlite3_step() should not be called again on 3307 ** the VM. More information may be found by calling [sqlite3_errmsg()]. 3308 ** ^With the legacy interface, a more specific error code (for example, 3309 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3310 ** can be obtained by calling [sqlite3_reset()] on the 3311 ** [prepared statement]. ^In the "v2" interface, 3312 ** the more specific error code is returned directly by sqlite3_step(). 3313 ** 3314 ** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3315 ** Perhaps it was called on a [prepared statement] that has 3316 ** already been [sqlite3_finalize | finalized] or on one that had 3317 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3318 ** be the case that the same database connection is being used by two or 3319 ** more threads at the same moment in time. 3320 ** 3321 ** For all versions of SQLite up to and including 3.6.23.1, a call to 3322 ** [sqlite3_reset()] was required after sqlite3_step() returned anything 3323 ** other than [SQLITE_ROW] before any subsequent invocation of 3324 ** sqlite3_step(). Failure to reset the prepared statement using 3325 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3326 ** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3327 ** calling [sqlite3_reset()] automatically in this circumstance rather 3328 ** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3329 ** break because any application that ever receives an SQLITE_MISUSE error 3330 ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3331 ** can be used to restore the legacy behavior. 3332 ** 3333 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3334 ** API always returns a generic error code, [SQLITE_ERROR], following any 3335 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3336 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3337 ** specific [error codes] that better describes the error. 3338 ** We admit that this is a goofy design. The problem has been fixed 3339 ** with the "v2" interface. If you prepare all of your SQL statements 3340 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3341 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3342 ** then the more specific [error codes] are returned directly 3343 ** by sqlite3_step(). The use of the "v2" interface is recommended. 3344 */ 3345 SQLITE_API int sqlite3_step(sqlite3_stmt*); 3346 3347 /* 3348 ** CAPI3REF: Number of columns in a result set 3349 ** 3350 ** ^The sqlite3_data_count(P) interface returns the number of columns in the 3351 ** current row of the result set of [prepared statement] P. 3352 ** ^If prepared statement P does not have results ready to return 3353 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3354 ** interfaces) then sqlite3_data_count(P) returns 0. 3355 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3356 ** 3357 ** See also: [sqlite3_column_count()] 3358 */ 3359 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt); 3360 3361 /* 3362 ** CAPI3REF: Fundamental Datatypes 3363 ** KEYWORDS: SQLITE_TEXT 3364 ** 3365 ** ^(Every value in SQLite has one of five fundamental datatypes: 3366 ** 3367 ** <ul> 3368 ** <li> 64-bit signed integer 3369 ** <li> 64-bit IEEE floating point number 3370 ** <li> string 3371 ** <li> BLOB 3372 ** <li> NULL 3373 ** </ul>)^ 3374 ** 3375 ** These constants are codes for each of those types. 3376 ** 3377 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3378 ** for a completely different meaning. Software that links against both 3379 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3380 ** SQLITE_TEXT. 3381 */ 3382 #define SQLITE_INTEGER 1 3383 #define SQLITE_FLOAT 2 3384 #define SQLITE_BLOB 4 3385 #define SQLITE_NULL 5 3386 #ifdef SQLITE_TEXT 3387 # undef SQLITE_TEXT 3388 #else 3389 # define SQLITE_TEXT 3 3390 #endif 3391 #define SQLITE3_TEXT 3 3392 3393 /* 3394 ** CAPI3REF: Result Values From A Query 3395 ** KEYWORDS: {column access functions} 3396 ** 3397 ** These routines form the "result set" interface. 3398 ** 3399 ** ^These routines return information about a single column of the current 3400 ** result row of a query. ^In every case the first argument is a pointer 3401 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3402 ** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3403 ** and the second argument is the index of the column for which information 3404 ** should be returned. ^The leftmost column of the result set has the index 0. 3405 ** ^The number of columns in the result can be determined using 3406 ** [sqlite3_column_count()]. 3407 ** 3408 ** If the SQL statement does not currently point to a valid row, or if the 3409 ** column index is out of range, the result is undefined. 3410 ** These routines may only be called when the most recent call to 3411 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3412 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3413 ** If any of these routines are called after [sqlite3_reset()] or 3414 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3415 ** something other than [SQLITE_ROW], the results are undefined. 3416 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3417 ** are called from a different thread while any of these routines 3418 ** are pending, then the results are undefined. 3419 ** 3420 ** ^The sqlite3_column_type() routine returns the 3421 ** [SQLITE_INTEGER | datatype code] for the initial data type 3422 ** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3423 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3424 ** returned by sqlite3_column_type() is only meaningful if no type 3425 ** conversions have occurred as described below. After a type conversion, 3426 ** the value returned by sqlite3_column_type() is undefined. Future 3427 ** versions of SQLite may change the behavior of sqlite3_column_type() 3428 ** following a type conversion. 3429 ** 3430 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3431 ** routine returns the number of bytes in that BLOB or string. 3432 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3433 ** the string to UTF-8 and then returns the number of bytes. 3434 ** ^If the result is a numeric value then sqlite3_column_bytes() uses 3435 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3436 ** the number of bytes in that string. 3437 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3438 ** 3439 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3440 ** routine returns the number of bytes in that BLOB or string. 3441 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3442 ** the string to UTF-16 and then returns the number of bytes. 3443 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3444 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3445 ** the number of bytes in that string. 3446 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3447 ** 3448 ** ^The values returned by [sqlite3_column_bytes()] and 3449 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3450 ** of the string. ^For clarity: the values returned by 3451 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3452 ** bytes in the string, not the number of characters. 3453 ** 3454 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3455 ** even empty strings, are always zero terminated. ^The return 3456 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3457 ** 3458 ** ^The object returned by [sqlite3_column_value()] is an 3459 ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3460 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3461 ** If the [unprotected sqlite3_value] object returned by 3462 ** [sqlite3_column_value()] is used in any other way, including calls 3463 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3464 ** or [sqlite3_value_bytes()], then the behavior is undefined. 3465 ** 3466 ** These routines attempt to convert the value where appropriate. ^For 3467 ** example, if the internal representation is FLOAT and a text result 3468 ** is requested, [sqlite3_snprintf()] is used internally to perform the 3469 ** conversion automatically. ^(The following table details the conversions 3470 ** that are applied: 3471 ** 3472 ** <blockquote> 3473 ** <table border="1"> 3474 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3475 ** 3476 ** <tr><td> NULL <td> INTEGER <td> Result is 0 3477 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3478 ** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3479 ** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3480 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3481 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3482 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3483 ** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3484 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3485 ** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3486 ** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3487 ** <tr><td> TEXT <td> FLOAT <td> Use atof() 3488 ** <tr><td> TEXT <td> BLOB <td> No change 3489 ** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3490 ** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3491 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3492 ** </table> 3493 ** </blockquote>)^ 3494 ** 3495 ** The table above makes reference to standard C library functions atoi() 3496 ** and atof(). SQLite does not really use these functions. It has its 3497 ** own equivalent internal routines. The atoi() and atof() names are 3498 ** used in the table for brevity and because they are familiar to most 3499 ** C programmers. 3500 ** 3501 ** Note that when type conversions occur, pointers returned by prior 3502 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3503 ** sqlite3_column_text16() may be invalidated. 3504 ** Type conversions and pointer invalidations might occur 3505 ** in the following cases: 3506 ** 3507 ** <ul> 3508 ** <li> The initial content is a BLOB and sqlite3_column_text() or 3509 ** sqlite3_column_text16() is called. A zero-terminator might 3510 ** need to be added to the string.</li> 3511 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3512 ** sqlite3_column_text16() is called. The content must be converted 3513 ** to UTF-16.</li> 3514 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3515 ** sqlite3_column_text() is called. The content must be converted 3516 ** to UTF-8.</li> 3517 ** </ul> 3518 ** 3519 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3520 ** not invalidate a prior pointer, though of course the content of the buffer 3521 ** that the prior pointer references will have been modified. Other kinds 3522 ** of conversion are done in place when it is possible, but sometimes they 3523 ** are not possible and in those cases prior pointers are invalidated. 3524 ** 3525 ** The safest and easiest to remember policy is to invoke these routines 3526 ** in one of the following ways: 3527 ** 3528 ** <ul> 3529 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3530 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3531 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3532 ** </ul> 3533 ** 3534 ** In other words, you should call sqlite3_column_text(), 3535 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3536 ** into the desired format, then invoke sqlite3_column_bytes() or 3537 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3538 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3539 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3540 ** with calls to sqlite3_column_bytes(). 3541 ** 3542 ** ^The pointers returned are valid until a type conversion occurs as 3543 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3544 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3545 ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3546 ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3547 ** [sqlite3_free()]. 3548 ** 3549 ** ^(If a memory allocation error occurs during the evaluation of any 3550 ** of these routines, a default value is returned. The default value 3551 ** is either the integer 0, the floating point number 0.0, or a NULL 3552 ** pointer. Subsequent calls to [sqlite3_errcode()] will return 3553 ** [SQLITE_NOMEM].)^ 3554 */ 3555 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3556 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3557 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3558 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol); 3559 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol); 3560 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3561 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3562 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3563 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol); 3564 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3565 3566 /* 3567 ** CAPI3REF: Destroy A Prepared Statement Object 3568 ** 3569 ** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3570 ** ^If the most recent evaluation of the statement encountered no errors 3571 ** or if the statement is never been evaluated, then sqlite3_finalize() returns 3572 ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 3573 ** sqlite3_finalize(S) returns the appropriate [error code] or 3574 ** [extended error code]. 3575 ** 3576 ** ^The sqlite3_finalize(S) routine can be called at any point during 3577 ** the life cycle of [prepared statement] S: 3578 ** before statement S is ever evaluated, after 3579 ** one or more calls to [sqlite3_reset()], or after any call 3580 ** to [sqlite3_step()] regardless of whether or not the statement has 3581 ** completed execution. 3582 ** 3583 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 3584 ** 3585 ** The application must finalize every [prepared statement] in order to avoid 3586 ** resource leaks. It is a grievous error for the application to try to use 3587 ** a prepared statement after it has been finalized. Any use of a prepared 3588 ** statement after it has been finalized can result in undefined and 3589 ** undesirable behavior such as segfaults and heap corruption. 3590 */ 3591 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt); 3592 3593 /* 3594 ** CAPI3REF: Reset A Prepared Statement Object 3595 ** 3596 ** The sqlite3_reset() function is called to reset a [prepared statement] 3597 ** object back to its initial state, ready to be re-executed. 3598 ** ^Any SQL statement variables that had values bound to them using 3599 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3600 ** Use [sqlite3_clear_bindings()] to reset the bindings. 3601 ** 3602 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3603 ** back to the beginning of its program. 3604 ** 3605 ** ^If the most recent call to [sqlite3_step(S)] for the 3606 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3607 ** or if [sqlite3_step(S)] has never before been called on S, 3608 ** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3609 ** 3610 ** ^If the most recent call to [sqlite3_step(S)] for the 3611 ** [prepared statement] S indicated an error, then 3612 ** [sqlite3_reset(S)] returns an appropriate [error code]. 3613 ** 3614 ** ^The [sqlite3_reset(S)] interface does not change the values 3615 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3616 */ 3617 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt); 3618 3619 /* 3620 ** CAPI3REF: Create Or Redefine SQL Functions 3621 ** KEYWORDS: {function creation routines} 3622 ** KEYWORDS: {application-defined SQL function} 3623 ** KEYWORDS: {application-defined SQL functions} 3624 ** 3625 ** ^These functions (collectively known as "function creation routines") 3626 ** are used to add SQL functions or aggregates or to redefine the behavior 3627 ** of existing SQL functions or aggregates. The only differences between 3628 ** these routines are the text encoding expected for 3629 ** the second parameter (the name of the function being created) 3630 ** and the presence or absence of a destructor callback for 3631 ** the application data pointer. 3632 ** 3633 ** ^The first parameter is the [database connection] to which the SQL 3634 ** function is to be added. ^If an application uses more than one database 3635 ** connection then application-defined SQL functions must be added 3636 ** to each database connection separately. 3637 ** 3638 ** ^The second parameter is the name of the SQL function to be created or 3639 ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 3640 ** representation, exclusive of the zero-terminator. ^Note that the name 3641 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 3642 ** ^Any attempt to create a function with a longer name 3643 ** will result in [SQLITE_MISUSE] being returned. 3644 ** 3645 ** ^The third parameter (nArg) 3646 ** is the number of arguments that the SQL function or 3647 ** aggregate takes. ^If this parameter is -1, then the SQL function or 3648 ** aggregate may take any number of arguments between 0 and the limit 3649 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3650 ** parameter is less than -1 or greater than 127 then the behavior is 3651 ** undefined. 3652 ** 3653 ** ^The fourth parameter, eTextRep, specifies what 3654 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3655 ** its parameters. Every SQL function implementation must be able to work 3656 ** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3657 ** more efficient with one encoding than another. ^An application may 3658 ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3659 ** times with the same function but with different values of eTextRep. 3660 ** ^When multiple implementations of the same function are available, SQLite 3661 ** will pick the one that involves the least amount of data conversion. 3662 ** If there is only a single implementation which does not care what text 3663 ** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3664 ** 3665 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3666 ** function can gain access to this pointer using [sqlite3_user_data()].)^ 3667 ** 3668 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 3669 ** pointers to C-language functions that implement the SQL function or 3670 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3671 ** callback only; NULL pointers must be passed as the xStep and xFinal 3672 ** parameters. ^An aggregate SQL function requires an implementation of xStep 3673 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 3674 ** SQL function or aggregate, pass NULL pointers for all three function 3675 ** callbacks. 3676 ** 3677 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 3678 ** then it is destructor for the application data pointer. 3679 ** The destructor is invoked when the function is deleted, either by being 3680 ** overloaded or when the database connection closes.)^ 3681 ** ^The destructor is also invoked if the call to 3682 ** sqlite3_create_function_v2() fails. 3683 ** ^When the destructor callback of the tenth parameter is invoked, it 3684 ** is passed a single argument which is a copy of the application data 3685 ** pointer which was the fifth parameter to sqlite3_create_function_v2(). 3686 ** 3687 ** ^It is permitted to register multiple implementations of the same 3688 ** functions with the same name but with either differing numbers of 3689 ** arguments or differing preferred text encodings. ^SQLite will use 3690 ** the implementation that most closely matches the way in which the 3691 ** SQL function is used. ^A function implementation with a non-negative 3692 ** nArg parameter is a better match than a function implementation with 3693 ** a negative nArg. ^A function where the preferred text encoding 3694 ** matches the database encoding is a better 3695 ** match than a function where the encoding is different. 3696 ** ^A function where the encoding difference is between UTF16le and UTF16be 3697 ** is a closer match than a function where the encoding difference is 3698 ** between UTF8 and UTF16. 3699 ** 3700 ** ^Built-in functions may be overloaded by new application-defined functions. 3701 ** 3702 ** ^An application-defined function is permitted to call other 3703 ** SQLite interfaces. However, such calls must not 3704 ** close the database connection nor finalize or reset the prepared 3705 ** statement in which the function is running. 3706 */ 3707 SQLITE_API int sqlite3_create_function( 3708 sqlite3 *db, 3709 const char *zFunctionName, 3710 int nArg, 3711 int eTextRep, 3712 void *pApp, 3713 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3714 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3715 void (*xFinal)(sqlite3_context*) 3716 ); 3717 SQLITE_API int sqlite3_create_function16( 3718 sqlite3 *db, 3719 const void *zFunctionName, 3720 int nArg, 3721 int eTextRep, 3722 void *pApp, 3723 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3724 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3725 void (*xFinal)(sqlite3_context*) 3726 ); 3727 SQLITE_API int sqlite3_create_function_v2( 3728 sqlite3 *db, 3729 const char *zFunctionName, 3730 int nArg, 3731 int eTextRep, 3732 void *pApp, 3733 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3734 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3735 void (*xFinal)(sqlite3_context*), 3736 void(*xDestroy)(void*) 3737 ); 3738 3739 /* 3740 ** CAPI3REF: Text Encodings 3741 ** 3742 ** These constant define integer codes that represent the various 3743 ** text encodings supported by SQLite. 3744 */ 3745 #define SQLITE_UTF8 1 3746 #define SQLITE_UTF16LE 2 3747 #define SQLITE_UTF16BE 3 3748 #define SQLITE_UTF16 4 /* Use native byte order */ 3749 #define SQLITE_ANY 5 /* sqlite3_create_function only */ 3750 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3751 3752 /* 3753 ** CAPI3REF: Deprecated Functions 3754 ** DEPRECATED 3755 ** 3756 ** These functions are [deprecated]. In order to maintain 3757 ** backwards compatibility with older code, these functions continue 3758 ** to be supported. However, new applications should avoid 3759 ** the use of these functions. To help encourage people to avoid 3760 ** using these functions, we are not going to tell you what they do. 3761 */ 3762 #ifndef SQLITE_OMIT_DEPRECATED 3763 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3764 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3765 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3766 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void); 3767 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3768 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3769 #endif 3770 3771 /* 3772 ** CAPI3REF: Obtaining SQL Function Parameter Values 3773 ** 3774 ** The C-language implementation of SQL functions and aggregates uses 3775 ** this set of interface routines to access the parameter values on 3776 ** the function or aggregate. 3777 ** 3778 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3779 ** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3780 ** define callbacks that implement the SQL functions and aggregates. 3781 ** The 3rd parameter to these callbacks is an array of pointers to 3782 ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3783 ** each parameter to the SQL function. These routines are used to 3784 ** extract values from the [sqlite3_value] objects. 3785 ** 3786 ** These routines work only with [protected sqlite3_value] objects. 3787 ** Any attempt to use these routines on an [unprotected sqlite3_value] 3788 ** object results in undefined behavior. 3789 ** 3790 ** ^These routines work just like the corresponding [column access functions] 3791 ** except that these routines take a single [protected sqlite3_value] object 3792 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3793 ** 3794 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string 3795 ** in the native byte-order of the host machine. ^The 3796 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3797 ** extract UTF-16 strings as big-endian and little-endian respectively. 3798 ** 3799 ** ^(The sqlite3_value_numeric_type() interface attempts to apply 3800 ** numeric affinity to the value. This means that an attempt is 3801 ** made to convert the value to an integer or floating point. If 3802 ** such a conversion is possible without loss of information (in other 3803 ** words, if the value is a string that looks like a number) 3804 ** then the conversion is performed. Otherwise no conversion occurs. 3805 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 3806 ** 3807 ** Please pay particular attention to the fact that the pointer returned 3808 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3809 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3810 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3811 ** or [sqlite3_value_text16()]. 3812 ** 3813 ** These routines must be called from the same thread as 3814 ** the SQL function that supplied the [sqlite3_value*] parameters. 3815 */ 3816 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*); 3817 SQLITE_API int sqlite3_value_bytes(sqlite3_value*); 3818 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*); 3819 SQLITE_API double sqlite3_value_double(sqlite3_value*); 3820 SQLITE_API int sqlite3_value_int(sqlite3_value*); 3821 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3822 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*); 3823 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*); 3824 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*); 3825 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*); 3826 SQLITE_API int sqlite3_value_type(sqlite3_value*); 3827 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*); 3828 3829 /* 3830 ** CAPI3REF: Obtain Aggregate Function Context 3831 ** 3832 ** Implementations of aggregate SQL functions use this 3833 ** routine to allocate memory for storing their state. 3834 ** 3835 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called 3836 ** for a particular aggregate function, SQLite 3837 ** allocates N of memory, zeroes out that memory, and returns a pointer 3838 ** to the new memory. ^On second and subsequent calls to 3839 ** sqlite3_aggregate_context() for the same aggregate function instance, 3840 ** the same buffer is returned. Sqlite3_aggregate_context() is normally 3841 ** called once for each invocation of the xStep callback and then one 3842 ** last time when the xFinal callback is invoked. ^(When no rows match 3843 ** an aggregate query, the xStep() callback of the aggregate function 3844 ** implementation is never called and xFinal() is called exactly once. 3845 ** In those cases, sqlite3_aggregate_context() might be called for the 3846 ** first time from within xFinal().)^ 3847 ** 3848 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is 3849 ** less than or equal to zero or if a memory allocate error occurs. 3850 ** 3851 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 3852 ** determined by the N parameter on first successful call. Changing the 3853 ** value of N in subsequent call to sqlite3_aggregate_context() within 3854 ** the same aggregate function instance will not resize the memory 3855 ** allocation.)^ 3856 ** 3857 ** ^SQLite automatically frees the memory allocated by 3858 ** sqlite3_aggregate_context() when the aggregate query concludes. 3859 ** 3860 ** The first parameter must be a copy of the 3861 ** [sqlite3_context | SQL function context] that is the first parameter 3862 ** to the xStep or xFinal callback routine that implements the aggregate 3863 ** function. 3864 ** 3865 ** This routine must be called from the same thread in which 3866 ** the aggregate SQL function is running. 3867 */ 3868 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 3869 3870 /* 3871 ** CAPI3REF: User Data For Functions 3872 ** 3873 ** ^The sqlite3_user_data() interface returns a copy of 3874 ** the pointer that was the pUserData parameter (the 5th parameter) 3875 ** of the [sqlite3_create_function()] 3876 ** and [sqlite3_create_function16()] routines that originally 3877 ** registered the application defined function. 3878 ** 3879 ** This routine must be called from the same thread in which 3880 ** the application-defined function is running. 3881 */ 3882 SQLITE_API void *sqlite3_user_data(sqlite3_context*); 3883 3884 /* 3885 ** CAPI3REF: Database Connection For Functions 3886 ** 3887 ** ^The sqlite3_context_db_handle() interface returns a copy of 3888 ** the pointer to the [database connection] (the 1st parameter) 3889 ** of the [sqlite3_create_function()] 3890 ** and [sqlite3_create_function16()] routines that originally 3891 ** registered the application defined function. 3892 */ 3893 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 3894 3895 /* 3896 ** CAPI3REF: Function Auxiliary Data 3897 ** 3898 ** The following two functions may be used by scalar SQL functions to 3899 ** associate metadata with argument values. If the same value is passed to 3900 ** multiple invocations of the same SQL function during query execution, under 3901 ** some circumstances the associated metadata may be preserved. This may 3902 ** be used, for example, to add a regular-expression matching scalar 3903 ** function. The compiled version of the regular expression is stored as 3904 ** metadata associated with the SQL value passed as the regular expression 3905 ** pattern. The compiled regular expression can be reused on multiple 3906 ** invocations of the same function so that the original pattern string 3907 ** does not need to be recompiled on each invocation. 3908 ** 3909 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 3910 ** associated by the sqlite3_set_auxdata() function with the Nth argument 3911 ** value to the application-defined function. ^If no metadata has been ever 3912 ** been set for the Nth argument of the function, or if the corresponding 3913 ** function parameter has changed since the meta-data was set, 3914 ** then sqlite3_get_auxdata() returns a NULL pointer. 3915 ** 3916 ** ^The sqlite3_set_auxdata() interface saves the metadata 3917 ** pointed to by its 3rd parameter as the metadata for the N-th 3918 ** argument of the application-defined function. Subsequent 3919 ** calls to sqlite3_get_auxdata() might return this data, if it has 3920 ** not been destroyed. 3921 ** ^If it is not NULL, SQLite will invoke the destructor 3922 ** function given by the 4th parameter to sqlite3_set_auxdata() on 3923 ** the metadata when the corresponding function parameter changes 3924 ** or when the SQL statement completes, whichever comes first. 3925 ** 3926 ** SQLite is free to call the destructor and drop metadata on any 3927 ** parameter of any function at any time. ^The only guarantee is that 3928 ** the destructor will be called before the metadata is dropped. 3929 ** 3930 ** ^(In practice, metadata is preserved between function calls for 3931 ** expressions that are constant at compile time. This includes literal 3932 ** values and [parameters].)^ 3933 ** 3934 ** These routines must be called from the same thread in which 3935 ** the SQL function is running. 3936 */ 3937 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N); 3938 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 3939 3940 3941 /* 3942 ** CAPI3REF: Constants Defining Special Destructor Behavior 3943 ** 3944 ** These are special values for the destructor that is passed in as the 3945 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 3946 ** argument is SQLITE_STATIC, it means that the content pointer is constant 3947 ** and will never change. It does not need to be destroyed. ^The 3948 ** SQLITE_TRANSIENT value means that the content will likely change in 3949 ** the near future and that SQLite should make its own private copy of 3950 ** the content before returning. 3951 ** 3952 ** The typedef is necessary to work around problems in certain 3953 ** C++ compilers. See ticket #2191. 3954 */ 3955 typedef void (*sqlite3_destructor_type)(void*); 3956 #define SQLITE_STATIC ((sqlite3_destructor_type)0) 3957 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 3958 3959 /* 3960 ** CAPI3REF: Setting The Result Of An SQL Function 3961 ** 3962 ** These routines are used by the xFunc or xFinal callbacks that 3963 ** implement SQL functions and aggregates. See 3964 ** [sqlite3_create_function()] and [sqlite3_create_function16()] 3965 ** for additional information. 3966 ** 3967 ** These functions work very much like the [parameter binding] family of 3968 ** functions used to bind values to host parameters in prepared statements. 3969 ** Refer to the [SQL parameter] documentation for additional information. 3970 ** 3971 ** ^The sqlite3_result_blob() interface sets the result from 3972 ** an application-defined function to be the BLOB whose content is pointed 3973 ** to by the second parameter and which is N bytes long where N is the 3974 ** third parameter. 3975 ** 3976 ** ^The sqlite3_result_zeroblob() interfaces set the result of 3977 ** the application-defined function to be a BLOB containing all zero 3978 ** bytes and N bytes in size, where N is the value of the 2nd parameter. 3979 ** 3980 ** ^The sqlite3_result_double() interface sets the result from 3981 ** an application-defined function to be a floating point value specified 3982 ** by its 2nd argument. 3983 ** 3984 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions 3985 ** cause the implemented SQL function to throw an exception. 3986 ** ^SQLite uses the string pointed to by the 3987 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 3988 ** as the text of an error message. ^SQLite interprets the error 3989 ** message string from sqlite3_result_error() as UTF-8. ^SQLite 3990 ** interprets the string from sqlite3_result_error16() as UTF-16 in native 3991 ** byte order. ^If the third parameter to sqlite3_result_error() 3992 ** or sqlite3_result_error16() is negative then SQLite takes as the error 3993 ** message all text up through the first zero character. 3994 ** ^If the third parameter to sqlite3_result_error() or 3995 ** sqlite3_result_error16() is non-negative then SQLite takes that many 3996 ** bytes (not characters) from the 2nd parameter as the error message. 3997 ** ^The sqlite3_result_error() and sqlite3_result_error16() 3998 ** routines make a private copy of the error message text before 3999 ** they return. Hence, the calling function can deallocate or 4000 ** modify the text after they return without harm. 4001 ** ^The sqlite3_result_error_code() function changes the error code 4002 ** returned by SQLite as a result of an error in a function. ^By default, 4003 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4004 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4005 ** 4006 ** ^The sqlite3_result_toobig() interface causes SQLite to throw an error 4007 ** indicating that a string or BLOB is too long to represent. 4008 ** 4009 ** ^The sqlite3_result_nomem() interface causes SQLite to throw an error 4010 ** indicating that a memory allocation failed. 4011 ** 4012 ** ^The sqlite3_result_int() interface sets the return value 4013 ** of the application-defined function to be the 32-bit signed integer 4014 ** value given in the 2nd argument. 4015 ** ^The sqlite3_result_int64() interface sets the return value 4016 ** of the application-defined function to be the 64-bit signed integer 4017 ** value given in the 2nd argument. 4018 ** 4019 ** ^The sqlite3_result_null() interface sets the return value 4020 ** of the application-defined function to be NULL. 4021 ** 4022 ** ^The sqlite3_result_text(), sqlite3_result_text16(), 4023 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4024 ** set the return value of the application-defined function to be 4025 ** a text string which is represented as UTF-8, UTF-16 native byte order, 4026 ** UTF-16 little endian, or UTF-16 big endian, respectively. 4027 ** ^SQLite takes the text result from the application from 4028 ** the 2nd parameter of the sqlite3_result_text* interfaces. 4029 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4030 ** is negative, then SQLite takes result text from the 2nd parameter 4031 ** through the first zero character. 4032 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4033 ** is non-negative, then as many bytes (not characters) of the text 4034 ** pointed to by the 2nd parameter are taken as the application-defined 4035 ** function result. 4036 ** ^If the 4th parameter to the sqlite3_result_text* interfaces 4037 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4038 ** function as the destructor on the text or BLOB result when it has 4039 ** finished using that result. 4040 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4041 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4042 ** assumes that the text or BLOB result is in constant space and does not 4043 ** copy the content of the parameter nor call a destructor on the content 4044 ** when it has finished using that result. 4045 ** ^If the 4th parameter to the sqlite3_result_text* interfaces 4046 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4047 ** then SQLite makes a copy of the result into space obtained from 4048 ** from [sqlite3_malloc()] before it returns. 4049 ** 4050 ** ^The sqlite3_result_value() interface sets the result of 4051 ** the application-defined function to be a copy the 4052 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4053 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4054 ** so that the [sqlite3_value] specified in the parameter may change or 4055 ** be deallocated after sqlite3_result_value() returns without harm. 4056 ** ^A [protected sqlite3_value] object may always be used where an 4057 ** [unprotected sqlite3_value] object is required, so either 4058 ** kind of [sqlite3_value] object can be used with this interface. 4059 ** 4060 ** If these routines are called from within the different thread 4061 ** than the one containing the application-defined function that received 4062 ** the [sqlite3_context] pointer, the results are undefined. 4063 */ 4064 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4065 SQLITE_API void sqlite3_result_double(sqlite3_context*, double); 4066 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int); 4067 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int); 4068 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*); 4069 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*); 4070 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int); 4071 SQLITE_API void sqlite3_result_int(sqlite3_context*, int); 4072 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4073 SQLITE_API void sqlite3_result_null(sqlite3_context*); 4074 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4075 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4076 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4077 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4078 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4079 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n); 4080 4081 /* 4082 ** CAPI3REF: Define New Collating Sequences 4083 ** 4084 ** ^These functions add, remove, or modify a [collation] associated 4085 ** with the [database connection] specified as the first argument. 4086 ** 4087 ** ^The name of the collation is a UTF-8 string 4088 ** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4089 ** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4090 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4091 ** considered to be the same name. 4092 ** 4093 ** ^(The third argument (eTextRep) must be one of the constants: 4094 ** <ul> 4095 ** <li> [SQLITE_UTF8], 4096 ** <li> [SQLITE_UTF16LE], 4097 ** <li> [SQLITE_UTF16BE], 4098 ** <li> [SQLITE_UTF16], or 4099 ** <li> [SQLITE_UTF16_ALIGNED]. 4100 ** </ul>)^ 4101 ** ^The eTextRep argument determines the encoding of strings passed 4102 ** to the collating function callback, xCallback. 4103 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4104 ** force strings to be UTF16 with native byte order. 4105 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4106 ** on an even byte address. 4107 ** 4108 ** ^The fourth argument, pArg, is an application data pointer that is passed 4109 ** through as the first argument to the collating function callback. 4110 ** 4111 ** ^The fifth argument, xCallback, is a pointer to the collating function. 4112 ** ^Multiple collating functions can be registered using the same name but 4113 ** with different eTextRep parameters and SQLite will use whichever 4114 ** function requires the least amount of data transformation. 4115 ** ^If the xCallback argument is NULL then the collating function is 4116 ** deleted. ^When all collating functions having the same name are deleted, 4117 ** that collation is no longer usable. 4118 ** 4119 ** ^The collating function callback is invoked with a copy of the pArg 4120 ** application data pointer and with two strings in the encoding specified 4121 ** by the eTextRep argument. The collating function must return an 4122 ** integer that is negative, zero, or positive 4123 ** if the first string is less than, equal to, or greater than the second, 4124 ** respectively. A collating function must always return the same answer 4125 ** given the same inputs. If two or more collating functions are registered 4126 ** to the same collation name (using different eTextRep values) then all 4127 ** must give an equivalent answer when invoked with equivalent strings. 4128 ** The collating function must obey the following properties for all 4129 ** strings A, B, and C: 4130 ** 4131 ** <ol> 4132 ** <li> If A==B then B==A. 4133 ** <li> If A==B and B==C then A==C. 4134 ** <li> If A<B THEN B>A. 4135 ** <li> If A<B and B<C then A<C. 4136 ** </ol> 4137 ** 4138 ** If a collating function fails any of the above constraints and that 4139 ** collating function is registered and used, then the behavior of SQLite 4140 ** is undefined. 4141 ** 4142 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4143 ** with the addition that the xDestroy callback is invoked on pArg when 4144 ** the collating function is deleted. 4145 ** ^Collating functions are deleted when they are overridden by later 4146 ** calls to the collation creation functions or when the 4147 ** [database connection] is closed using [sqlite3_close()]. 4148 ** 4149 ** ^The xDestroy callback is <u>not</u> called if the 4150 ** sqlite3_create_collation_v2() function fails. Applications that invoke 4151 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4152 ** check the return code and dispose of the application data pointer 4153 ** themselves rather than expecting SQLite to deal with it for them. 4154 ** This is different from every other SQLite interface. The inconsistency 4155 ** is unfortunate but cannot be changed without breaking backwards 4156 ** compatibility. 4157 ** 4158 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4159 */ 4160 SQLITE_API int sqlite3_create_collation( 4161 sqlite3*, 4162 const char *zName, 4163 int eTextRep, 4164 void *pArg, 4165 int(*xCompare)(void*,int,const void*,int,const void*) 4166 ); 4167 SQLITE_API int sqlite3_create_collation_v2( 4168 sqlite3*, 4169 const char *zName, 4170 int eTextRep, 4171 void *pArg, 4172 int(*xCompare)(void*,int,const void*,int,const void*), 4173 void(*xDestroy)(void*) 4174 ); 4175 SQLITE_API int sqlite3_create_collation16( 4176 sqlite3*, 4177 const void *zName, 4178 int eTextRep, 4179 void *pArg, 4180 int(*xCompare)(void*,int,const void*,int,const void*) 4181 ); 4182 4183 /* 4184 ** CAPI3REF: Collation Needed Callbacks 4185 ** 4186 ** ^To avoid having to register all collation sequences before a database 4187 ** can be used, a single callback function may be registered with the 4188 ** [database connection] to be invoked whenever an undefined collation 4189 ** sequence is required. 4190 ** 4191 ** ^If the function is registered using the sqlite3_collation_needed() API, 4192 ** then it is passed the names of undefined collation sequences as strings 4193 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4194 ** the names are passed as UTF-16 in machine native byte order. 4195 ** ^A call to either function replaces the existing collation-needed callback. 4196 ** 4197 ** ^(When the callback is invoked, the first argument passed is a copy 4198 ** of the second argument to sqlite3_collation_needed() or 4199 ** sqlite3_collation_needed16(). The second argument is the database 4200 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4201 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4202 ** sequence function required. The fourth parameter is the name of the 4203 ** required collation sequence.)^ 4204 ** 4205 ** The callback function should register the desired collation using 4206 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4207 ** [sqlite3_create_collation_v2()]. 4208 */ 4209 SQLITE_API int sqlite3_collation_needed( 4210 sqlite3*, 4211 void*, 4212 void(*)(void*,sqlite3*,int eTextRep,const char*) 4213 ); 4214 SQLITE_API int sqlite3_collation_needed16( 4215 sqlite3*, 4216 void*, 4217 void(*)(void*,sqlite3*,int eTextRep,const void*) 4218 ); 4219 4220 #ifdef SQLITE_HAS_CODEC 4221 /* 4222 ** Specify the key for an encrypted database. This routine should be 4223 ** called right after sqlite3_open(). 4224 ** 4225 ** The code to implement this API is not available in the public release 4226 ** of SQLite. 4227 */ 4228 SQLITE_API int sqlite3_key( 4229 sqlite3 *db, /* Database to be rekeyed */ 4230 const void *pKey, int nKey /* The key */ 4231 ); 4232 4233 /* 4234 ** Change the key on an open database. If the current database is not 4235 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4236 ** database is decrypted. 4237 ** 4238 ** The code to implement this API is not available in the public release 4239 ** of SQLite. 4240 */ 4241 SQLITE_API int sqlite3_rekey( 4242 sqlite3 *db, /* Database to be rekeyed */ 4243 const void *pKey, int nKey /* The new key */ 4244 ); 4245 4246 /* 4247 ** Specify the activation key for a SEE database. Unless 4248 ** activated, none of the SEE routines will work. 4249 */ 4250 SQLITE_API void sqlite3_activate_see( 4251 const char *zPassPhrase /* Activation phrase */ 4252 ); 4253 #endif 4254 4255 #ifdef SQLITE_ENABLE_CEROD 4256 /* 4257 ** Specify the activation key for a CEROD database. Unless 4258 ** activated, none of the CEROD routines will work. 4259 */ 4260 SQLITE_API void sqlite3_activate_cerod( 4261 const char *zPassPhrase /* Activation phrase */ 4262 ); 4263 #endif 4264 4265 /* 4266 ** CAPI3REF: Suspend Execution For A Short Time 4267 ** 4268 ** The sqlite3_sleep() function causes the current thread to suspend execution 4269 ** for at least a number of milliseconds specified in its parameter. 4270 ** 4271 ** If the operating system does not support sleep requests with 4272 ** millisecond time resolution, then the time will be rounded up to 4273 ** the nearest second. The number of milliseconds of sleep actually 4274 ** requested from the operating system is returned. 4275 ** 4276 ** ^SQLite implements this interface by calling the xSleep() 4277 ** method of the default [sqlite3_vfs] object. If the xSleep() method 4278 ** of the default VFS is not implemented correctly, or not implemented at 4279 ** all, then the behavior of sqlite3_sleep() may deviate from the description 4280 ** in the previous paragraphs. 4281 */ 4282 SQLITE_API int sqlite3_sleep(int); 4283 4284 /* 4285 ** CAPI3REF: Name Of The Folder Holding Temporary Files 4286 ** 4287 ** ^(If this global variable is made to point to a string which is 4288 ** the name of a folder (a.k.a. directory), then all temporary files 4289 ** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4290 ** will be placed in that directory.)^ ^If this variable 4291 ** is a NULL pointer, then SQLite performs a search for an appropriate 4292 ** temporary file directory. 4293 ** 4294 ** It is not safe to read or modify this variable in more than one 4295 ** thread at a time. It is not safe to read or modify this variable 4296 ** if a [database connection] is being used at the same time in a separate 4297 ** thread. 4298 ** It is intended that this variable be set once 4299 ** as part of process initialization and before any SQLite interface 4300 ** routines have been called and that this variable remain unchanged 4301 ** thereafter. 4302 ** 4303 ** ^The [temp_store_directory pragma] may modify this variable and cause 4304 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4305 ** the [temp_store_directory pragma] always assumes that any string 4306 ** that this variable points to is held in memory obtained from 4307 ** [sqlite3_malloc] and the pragma may attempt to free that memory 4308 ** using [sqlite3_free]. 4309 ** Hence, if this variable is modified directly, either it should be 4310 ** made NULL or made to point to memory obtained from [sqlite3_malloc] 4311 ** or else the use of the [temp_store_directory pragma] should be avoided. 4312 */ 4313 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory; 4314 4315 /* 4316 ** CAPI3REF: Test For Auto-Commit Mode 4317 ** KEYWORDS: {autocommit mode} 4318 ** 4319 ** ^The sqlite3_get_autocommit() interface returns non-zero or 4320 ** zero if the given database connection is or is not in autocommit mode, 4321 ** respectively. ^Autocommit mode is on by default. 4322 ** ^Autocommit mode is disabled by a [BEGIN] statement. 4323 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 4324 ** 4325 ** If certain kinds of errors occur on a statement within a multi-statement 4326 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 4327 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 4328 ** transaction might be rolled back automatically. The only way to 4329 ** find out whether SQLite automatically rolled back the transaction after 4330 ** an error is to use this function. 4331 ** 4332 ** If another thread changes the autocommit status of the database 4333 ** connection while this routine is running, then the return value 4334 ** is undefined. 4335 */ 4336 SQLITE_API int sqlite3_get_autocommit(sqlite3*); 4337 4338 /* 4339 ** CAPI3REF: Find The Database Handle Of A Prepared Statement 4340 ** 4341 ** ^The sqlite3_db_handle interface returns the [database connection] handle 4342 ** to which a [prepared statement] belongs. ^The [database connection] 4343 ** returned by sqlite3_db_handle is the same [database connection] 4344 ** that was the first argument 4345 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 4346 ** create the statement in the first place. 4347 */ 4348 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 4349 4350 /* 4351 ** CAPI3REF: Find the next prepared statement 4352 ** 4353 ** ^This interface returns a pointer to the next [prepared statement] after 4354 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 4355 ** then this interface returns a pointer to the first prepared statement 4356 ** associated with the database connection pDb. ^If no prepared statement 4357 ** satisfies the conditions of this routine, it returns NULL. 4358 ** 4359 ** The [database connection] pointer D in a call to 4360 ** [sqlite3_next_stmt(D,S)] must refer to an open database 4361 ** connection and in particular must not be a NULL pointer. 4362 */ 4363 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 4364 4365 /* 4366 ** CAPI3REF: Commit And Rollback Notification Callbacks 4367 ** 4368 ** ^The sqlite3_commit_hook() interface registers a callback 4369 ** function to be invoked whenever a transaction is [COMMIT | committed]. 4370 ** ^Any callback set by a previous call to sqlite3_commit_hook() 4371 ** for the same database connection is overridden. 4372 ** ^The sqlite3_rollback_hook() interface registers a callback 4373 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 4374 ** ^Any callback set by a previous call to sqlite3_rollback_hook() 4375 ** for the same database connection is overridden. 4376 ** ^The pArg argument is passed through to the callback. 4377 ** ^If the callback on a commit hook function returns non-zero, 4378 ** then the commit is converted into a rollback. 4379 ** 4380 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 4381 ** return the P argument from the previous call of the same function 4382 ** on the same [database connection] D, or NULL for 4383 ** the first call for each function on D. 4384 ** 4385 ** The callback implementation must not do anything that will modify 4386 ** the database connection that invoked the callback. Any actions 4387 ** to modify the database connection must be deferred until after the 4388 ** completion of the [sqlite3_step()] call that triggered the commit 4389 ** or rollback hook in the first place. 4390 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4391 ** database connections for the meaning of "modify" in this paragraph. 4392 ** 4393 ** ^Registering a NULL function disables the callback. 4394 ** 4395 ** ^When the commit hook callback routine returns zero, the [COMMIT] 4396 ** operation is allowed to continue normally. ^If the commit hook 4397 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 4398 ** ^The rollback hook is invoked on a rollback that results from a commit 4399 ** hook returning non-zero, just as it would be with any other rollback. 4400 ** 4401 ** ^For the purposes of this API, a transaction is said to have been 4402 ** rolled back if an explicit "ROLLBACK" statement is executed, or 4403 ** an error or constraint causes an implicit rollback to occur. 4404 ** ^The rollback callback is not invoked if a transaction is 4405 ** automatically rolled back because the database connection is closed. 4406 ** 4407 ** See also the [sqlite3_update_hook()] interface. 4408 */ 4409 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 4410 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 4411 4412 /* 4413 ** CAPI3REF: Data Change Notification Callbacks 4414 ** 4415 ** ^The sqlite3_update_hook() interface registers a callback function 4416 ** with the [database connection] identified by the first argument 4417 ** to be invoked whenever a row is updated, inserted or deleted. 4418 ** ^Any callback set by a previous call to this function 4419 ** for the same database connection is overridden. 4420 ** 4421 ** ^The second argument is a pointer to the function to invoke when a 4422 ** row is updated, inserted or deleted. 4423 ** ^The first argument to the callback is a copy of the third argument 4424 ** to sqlite3_update_hook(). 4425 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 4426 ** or [SQLITE_UPDATE], depending on the operation that caused the callback 4427 ** to be invoked. 4428 ** ^The third and fourth arguments to the callback contain pointers to the 4429 ** database and table name containing the affected row. 4430 ** ^The final callback parameter is the [rowid] of the row. 4431 ** ^In the case of an update, this is the [rowid] after the update takes place. 4432 ** 4433 ** ^(The update hook is not invoked when internal system tables are 4434 ** modified (i.e. sqlite_master and sqlite_sequence).)^ 4435 ** 4436 ** ^In the current implementation, the update hook 4437 ** is not invoked when duplication rows are deleted because of an 4438 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 4439 ** invoked when rows are deleted using the [truncate optimization]. 4440 ** The exceptions defined in this paragraph might change in a future 4441 ** release of SQLite. 4442 ** 4443 ** The update hook implementation must not do anything that will modify 4444 ** the database connection that invoked the update hook. Any actions 4445 ** to modify the database connection must be deferred until after the 4446 ** completion of the [sqlite3_step()] call that triggered the update hook. 4447 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4448 ** database connections for the meaning of "modify" in this paragraph. 4449 ** 4450 ** ^The sqlite3_update_hook(D,C,P) function 4451 ** returns the P argument from the previous call 4452 ** on the same [database connection] D, or NULL for 4453 ** the first call on D. 4454 ** 4455 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4456 ** interfaces. 4457 */ 4458 SQLITE_API void *sqlite3_update_hook( 4459 sqlite3*, 4460 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4461 void* 4462 ); 4463 4464 /* 4465 ** CAPI3REF: Enable Or Disable Shared Pager Cache 4466 ** KEYWORDS: {shared cache} 4467 ** 4468 ** ^(This routine enables or disables the sharing of the database cache 4469 ** and schema data structures between [database connection | connections] 4470 ** to the same database. Sharing is enabled if the argument is true 4471 ** and disabled if the argument is false.)^ 4472 ** 4473 ** ^Cache sharing is enabled and disabled for an entire process. 4474 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4475 ** sharing was enabled or disabled for each thread separately. 4476 ** 4477 ** ^(The cache sharing mode set by this interface effects all subsequent 4478 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4479 ** Existing database connections continue use the sharing mode 4480 ** that was in effect at the time they were opened.)^ 4481 ** 4482 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4483 ** successfully. An [error code] is returned otherwise.)^ 4484 ** 4485 ** ^Shared cache is disabled by default. But this might change in 4486 ** future releases of SQLite. Applications that care about shared 4487 ** cache setting should set it explicitly. 4488 ** 4489 ** See Also: [SQLite Shared-Cache Mode] 4490 */ 4491 SQLITE_API int sqlite3_enable_shared_cache(int); 4492 4493 /* 4494 ** CAPI3REF: Attempt To Free Heap Memory 4495 ** 4496 ** ^The sqlite3_release_memory() interface attempts to free N bytes 4497 ** of heap memory by deallocating non-essential memory allocations 4498 ** held by the database library. Memory used to cache database 4499 ** pages to improve performance is an example of non-essential memory. 4500 ** ^sqlite3_release_memory() returns the number of bytes actually freed, 4501 ** which might be more or less than the amount requested. 4502 ** ^The sqlite3_release_memory() routine is a no-op returning zero 4503 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4504 */ 4505 SQLITE_API int sqlite3_release_memory(int); 4506 4507 /* 4508 ** CAPI3REF: Impose A Limit On Heap Size 4509 ** 4510 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 4511 ** soft limit on the amount of heap memory that may be allocated by SQLite. 4512 ** ^SQLite strives to keep heap memory utilization below the soft heap 4513 ** limit by reducing the number of pages held in the page cache 4514 ** as heap memory usages approaches the limit. 4515 ** ^The soft heap limit is "soft" because even though SQLite strives to stay 4516 ** below the limit, it will exceed the limit rather than generate 4517 ** an [SQLITE_NOMEM] error. In other words, the soft heap limit 4518 ** is advisory only. 4519 ** 4520 ** ^The return value from sqlite3_soft_heap_limit64() is the size of 4521 ** the soft heap limit prior to the call. ^If the argument N is negative 4522 ** then no change is made to the soft heap limit. Hence, the current 4523 ** size of the soft heap limit can be determined by invoking 4524 ** sqlite3_soft_heap_limit64() with a negative argument. 4525 ** 4526 ** ^If the argument N is zero then the soft heap limit is disabled. 4527 ** 4528 ** ^(The soft heap limit is not enforced in the current implementation 4529 ** if one or more of following conditions are true: 4530 ** 4531 ** <ul> 4532 ** <li> The soft heap limit is set to zero. 4533 ** <li> Memory accounting is disabled using a combination of the 4534 ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 4535 ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 4536 ** <li> An alternative page cache implementation is specified using 4537 ** [sqlite3_config]([SQLITE_CONFIG_PCACHE],...). 4538 ** <li> The page cache allocates from its own memory pool supplied 4539 ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 4540 ** from the heap. 4541 ** </ul>)^ 4542 ** 4543 ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 4544 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 4545 ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 4546 ** the soft heap limit is enforced on every memory allocation. Without 4547 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 4548 ** when memory is allocated by the page cache. Testing suggests that because 4549 ** the page cache is the predominate memory user in SQLite, most 4550 ** applications will achieve adequate soft heap limit enforcement without 4551 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4552 ** 4553 ** The circumstances under which SQLite will enforce the soft heap limit may 4554 ** changes in future releases of SQLite. 4555 */ 4556 SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 4557 4558 /* 4559 ** CAPI3REF: Deprecated Soft Heap Limit Interface 4560 ** DEPRECATED 4561 ** 4562 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 4563 ** interface. This routine is provided for historical compatibility 4564 ** only. All new applications should use the 4565 ** [sqlite3_soft_heap_limit64()] interface rather than this one. 4566 */ 4567 SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 4568 4569 4570 /* 4571 ** CAPI3REF: Extract Metadata About A Column Of A Table 4572 ** 4573 ** ^This routine returns metadata about a specific column of a specific 4574 ** database table accessible using the [database connection] handle 4575 ** passed as the first function argument. 4576 ** 4577 ** ^The column is identified by the second, third and fourth parameters to 4578 ** this function. ^The second parameter is either the name of the database 4579 ** (i.e. "main", "temp", or an attached database) containing the specified 4580 ** table or NULL. ^If it is NULL, then all attached databases are searched 4581 ** for the table using the same algorithm used by the database engine to 4582 ** resolve unqualified table references. 4583 ** 4584 ** ^The third and fourth parameters to this function are the table and column 4585 ** name of the desired column, respectively. Neither of these parameters 4586 ** may be NULL. 4587 ** 4588 ** ^Metadata is returned by writing to the memory locations passed as the 5th 4589 ** and subsequent parameters to this function. ^Any of these arguments may be 4590 ** NULL, in which case the corresponding element of metadata is omitted. 4591 ** 4592 ** ^(<blockquote> 4593 ** <table border="1"> 4594 ** <tr><th> Parameter <th> Output<br>Type <th> Description 4595 ** 4596 ** <tr><td> 5th <td> const char* <td> Data type 4597 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4598 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4599 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4600 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4601 ** </table> 4602 ** </blockquote>)^ 4603 ** 4604 ** ^The memory pointed to by the character pointers returned for the 4605 ** declaration type and collation sequence is valid only until the next 4606 ** call to any SQLite API function. 4607 ** 4608 ** ^If the specified table is actually a view, an [error code] is returned. 4609 ** 4610 ** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4611 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4612 ** parameters are set for the explicitly declared column. ^(If there is no 4613 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4614 ** parameters are set as follows: 4615 ** 4616 ** <pre> 4617 ** data type: "INTEGER" 4618 ** collation sequence: "BINARY" 4619 ** not null: 0 4620 ** primary key: 1 4621 ** auto increment: 0 4622 ** </pre>)^ 4623 ** 4624 ** ^(This function may load one or more schemas from database files. If an 4625 ** error occurs during this process, or if the requested table or column 4626 ** cannot be found, an [error code] is returned and an error message left 4627 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4628 ** 4629 ** ^This API is only available if the library was compiled with the 4630 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4631 */ 4632 SQLITE_API int sqlite3_table_column_metadata( 4633 sqlite3 *db, /* Connection handle */ 4634 const char *zDbName, /* Database name or NULL */ 4635 const char *zTableName, /* Table name */ 4636 const char *zColumnName, /* Column name */ 4637 char const **pzDataType, /* OUTPUT: Declared data type */ 4638 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4639 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4640 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4641 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4642 ); 4643 4644 /* 4645 ** CAPI3REF: Load An Extension 4646 ** 4647 ** ^This interface loads an SQLite extension library from the named file. 4648 ** 4649 ** ^The sqlite3_load_extension() interface attempts to load an 4650 ** SQLite extension library contained in the file zFile. 4651 ** 4652 ** ^The entry point is zProc. 4653 ** ^zProc may be 0, in which case the name of the entry point 4654 ** defaults to "sqlite3_extension_init". 4655 ** ^The sqlite3_load_extension() interface returns 4656 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4657 ** ^If an error occurs and pzErrMsg is not 0, then the 4658 ** [sqlite3_load_extension()] interface shall attempt to 4659 ** fill *pzErrMsg with error message text stored in memory 4660 ** obtained from [sqlite3_malloc()]. The calling function 4661 ** should free this memory by calling [sqlite3_free()]. 4662 ** 4663 ** ^Extension loading must be enabled using 4664 ** [sqlite3_enable_load_extension()] prior to calling this API, 4665 ** otherwise an error will be returned. 4666 ** 4667 ** See also the [load_extension() SQL function]. 4668 */ 4669 SQLITE_API int sqlite3_load_extension( 4670 sqlite3 *db, /* Load the extension into this database connection */ 4671 const char *zFile, /* Name of the shared library containing extension */ 4672 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4673 char **pzErrMsg /* Put error message here if not 0 */ 4674 ); 4675 4676 /* 4677 ** CAPI3REF: Enable Or Disable Extension Loading 4678 ** 4679 ** ^So as not to open security holes in older applications that are 4680 ** unprepared to deal with extension loading, and as a means of disabling 4681 ** extension loading while evaluating user-entered SQL, the following API 4682 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4683 ** 4684 ** ^Extension loading is off by default. See ticket #1863. 4685 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1 4686 ** to turn extension loading on and call it with onoff==0 to turn 4687 ** it back off again. 4688 */ 4689 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4690 4691 /* 4692 ** CAPI3REF: Automatically Load Statically Linked Extensions 4693 ** 4694 ** ^This interface causes the xEntryPoint() function to be invoked for 4695 ** each new [database connection] that is created. The idea here is that 4696 ** xEntryPoint() is the entry point for a statically linked SQLite extension 4697 ** that is to be automatically loaded into all new database connections. 4698 ** 4699 ** ^(Even though the function prototype shows that xEntryPoint() takes 4700 ** no arguments and returns void, SQLite invokes xEntryPoint() with three 4701 ** arguments and expects and integer result as if the signature of the 4702 ** entry point where as follows: 4703 ** 4704 ** <blockquote><pre> 4705 ** int xEntryPoint( 4706 ** sqlite3 *db, 4707 ** const char **pzErrMsg, 4708 ** const struct sqlite3_api_routines *pThunk 4709 ** ); 4710 ** </pre></blockquote>)^ 4711 ** 4712 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 4713 ** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 4714 ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 4715 ** is NULL before calling the xEntryPoint(). ^SQLite will invoke 4716 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 4717 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 4718 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 4719 ** 4720 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 4721 ** on the list of automatic extensions is a harmless no-op. ^No entry point 4722 ** will be called more than once for each database connection that is opened. 4723 ** 4724 ** See also: [sqlite3_reset_auto_extension()]. 4725 */ 4726 SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4727 4728 /* 4729 ** CAPI3REF: Reset Automatic Extension Loading 4730 ** 4731 ** ^This interface disables all automatic extensions previously 4732 ** registered using [sqlite3_auto_extension()]. 4733 */ 4734 SQLITE_API void sqlite3_reset_auto_extension(void); 4735 4736 /* 4737 ** The interface to the virtual-table mechanism is currently considered 4738 ** to be experimental. The interface might change in incompatible ways. 4739 ** If this is a problem for you, do not use the interface at this time. 4740 ** 4741 ** When the virtual-table mechanism stabilizes, we will declare the 4742 ** interface fixed, support it indefinitely, and remove this comment. 4743 */ 4744 4745 /* 4746 ** Structures used by the virtual table interface 4747 */ 4748 typedef struct sqlite3_vtab sqlite3_vtab; 4749 typedef struct sqlite3_index_info sqlite3_index_info; 4750 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4751 typedef struct sqlite3_module sqlite3_module; 4752 4753 /* 4754 ** CAPI3REF: Virtual Table Object 4755 ** KEYWORDS: sqlite3_module {virtual table module} 4756 ** 4757 ** This structure, sometimes called a "virtual table module", 4758 ** defines the implementation of a [virtual tables]. 4759 ** This structure consists mostly of methods for the module. 4760 ** 4761 ** ^A virtual table module is created by filling in a persistent 4762 ** instance of this structure and passing a pointer to that instance 4763 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4764 ** ^The registration remains valid until it is replaced by a different 4765 ** module or until the [database connection] closes. The content 4766 ** of this structure must not change while it is registered with 4767 ** any database connection. 4768 */ 4769 struct sqlite3_module { 4770 int iVersion; 4771 int (*xCreate)(sqlite3*, void *pAux, 4772 int argc, const char *const*argv, 4773 sqlite3_vtab **ppVTab, char**); 4774 int (*xConnect)(sqlite3*, void *pAux, 4775 int argc, const char *const*argv, 4776 sqlite3_vtab **ppVTab, char**); 4777 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4778 int (*xDisconnect)(sqlite3_vtab *pVTab); 4779 int (*xDestroy)(sqlite3_vtab *pVTab); 4780 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4781 int (*xClose)(sqlite3_vtab_cursor*); 4782 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4783 int argc, sqlite3_value **argv); 4784 int (*xNext)(sqlite3_vtab_cursor*); 4785 int (*xEof)(sqlite3_vtab_cursor*); 4786 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4787 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4788 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4789 int (*xBegin)(sqlite3_vtab *pVTab); 4790 int (*xSync)(sqlite3_vtab *pVTab); 4791 int (*xCommit)(sqlite3_vtab *pVTab); 4792 int (*xRollback)(sqlite3_vtab *pVTab); 4793 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4794 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4795 void **ppArg); 4796 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4797 /* The methods above are in version 1 of the sqlite_module object. Those 4798 ** below are for version 2 and greater. */ 4799 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 4800 int (*xRelease)(sqlite3_vtab *pVTab, int); 4801 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 4802 }; 4803 4804 /* 4805 ** CAPI3REF: Virtual Table Indexing Information 4806 ** KEYWORDS: sqlite3_index_info 4807 ** 4808 ** The sqlite3_index_info structure and its substructures is used as part 4809 ** of the [virtual table] interface to 4810 ** pass information into and receive the reply from the [xBestIndex] 4811 ** method of a [virtual table module]. The fields under **Inputs** are the 4812 ** inputs to xBestIndex and are read-only. xBestIndex inserts its 4813 ** results into the **Outputs** fields. 4814 ** 4815 ** ^(The aConstraint[] array records WHERE clause constraints of the form: 4816 ** 4817 ** <blockquote>column OP expr</blockquote> 4818 ** 4819 ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 4820 ** stored in aConstraint[].op using one of the 4821 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 4822 ** ^(The index of the column is stored in 4823 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 4824 ** expr on the right-hand side can be evaluated (and thus the constraint 4825 ** is usable) and false if it cannot.)^ 4826 ** 4827 ** ^The optimizer automatically inverts terms of the form "expr OP column" 4828 ** and makes other simplifications to the WHERE clause in an attempt to 4829 ** get as many WHERE clause terms into the form shown above as possible. 4830 ** ^The aConstraint[] array only reports WHERE clause terms that are 4831 ** relevant to the particular virtual table being queried. 4832 ** 4833 ** ^Information about the ORDER BY clause is stored in aOrderBy[]. 4834 ** ^Each term of aOrderBy records a column of the ORDER BY clause. 4835 ** 4836 ** The [xBestIndex] method must fill aConstraintUsage[] with information 4837 ** about what parameters to pass to xFilter. ^If argvIndex>0 then 4838 ** the right-hand side of the corresponding aConstraint[] is evaluated 4839 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 4840 ** is true, then the constraint is assumed to be fully handled by the 4841 ** virtual table and is not checked again by SQLite.)^ 4842 ** 4843 ** ^The idxNum and idxPtr values are recorded and passed into the 4844 ** [xFilter] method. 4845 ** ^[sqlite3_free()] is used to free idxPtr if and only if 4846 ** needToFreeIdxPtr is true. 4847 ** 4848 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 4849 ** the correct order to satisfy the ORDER BY clause so that no separate 4850 ** sorting step is required. 4851 ** 4852 ** ^The estimatedCost value is an estimate of the cost of doing the 4853 ** particular lookup. A full scan of a table with N entries should have 4854 ** a cost of N. A binary search of a table of N entries should have a 4855 ** cost of approximately log(N). 4856 */ 4857 struct sqlite3_index_info { 4858 /* Inputs */ 4859 int nConstraint; /* Number of entries in aConstraint */ 4860 struct sqlite3_index_constraint { 4861 int iColumn; /* Column on left-hand side of constraint */ 4862 unsigned char op; /* Constraint operator */ 4863 unsigned char usable; /* True if this constraint is usable */ 4864 int iTermOffset; /* Used internally - xBestIndex should ignore */ 4865 } *aConstraint; /* Table of WHERE clause constraints */ 4866 int nOrderBy; /* Number of terms in the ORDER BY clause */ 4867 struct sqlite3_index_orderby { 4868 int iColumn; /* Column number */ 4869 unsigned char desc; /* True for DESC. False for ASC. */ 4870 } *aOrderBy; /* The ORDER BY clause */ 4871 /* Outputs */ 4872 struct sqlite3_index_constraint_usage { 4873 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 4874 unsigned char omit; /* Do not code a test for this constraint */ 4875 } *aConstraintUsage; 4876 int idxNum; /* Number used to identify the index */ 4877 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 4878 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 4879 int orderByConsumed; /* True if output is already ordered */ 4880 double estimatedCost; /* Estimated cost of using this index */ 4881 }; 4882 4883 /* 4884 ** CAPI3REF: Virtual Table Constraint Operator Codes 4885 ** 4886 ** These macros defined the allowed values for the 4887 ** [sqlite3_index_info].aConstraint[].op field. Each value represents 4888 ** an operator that is part of a constraint term in the wHERE clause of 4889 ** a query that uses a [virtual table]. 4890 */ 4891 #define SQLITE_INDEX_CONSTRAINT_EQ 2 4892 #define SQLITE_INDEX_CONSTRAINT_GT 4 4893 #define SQLITE_INDEX_CONSTRAINT_LE 8 4894 #define SQLITE_INDEX_CONSTRAINT_LT 16 4895 #define SQLITE_INDEX_CONSTRAINT_GE 32 4896 #define SQLITE_INDEX_CONSTRAINT_MATCH 64 4897 4898 /* 4899 ** CAPI3REF: Register A Virtual Table Implementation 4900 ** 4901 ** ^These routines are used to register a new [virtual table module] name. 4902 ** ^Module names must be registered before 4903 ** creating a new [virtual table] using the module and before using a 4904 ** preexisting [virtual table] for the module. 4905 ** 4906 ** ^The module name is registered on the [database connection] specified 4907 ** by the first parameter. ^The name of the module is given by the 4908 ** second parameter. ^The third parameter is a pointer to 4909 ** the implementation of the [virtual table module]. ^The fourth 4910 ** parameter is an arbitrary client data pointer that is passed through 4911 ** into the [xCreate] and [xConnect] methods of the virtual table module 4912 ** when a new virtual table is be being created or reinitialized. 4913 ** 4914 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which 4915 ** is a pointer to a destructor for the pClientData. ^SQLite will 4916 ** invoke the destructor function (if it is not NULL) when SQLite 4917 ** no longer needs the pClientData pointer. ^The destructor will also 4918 ** be invoked if the call to sqlite3_create_module_v2() fails. 4919 ** ^The sqlite3_create_module() 4920 ** interface is equivalent to sqlite3_create_module_v2() with a NULL 4921 ** destructor. 4922 */ 4923 SQLITE_API int sqlite3_create_module( 4924 sqlite3 *db, /* SQLite connection to register module with */ 4925 const char *zName, /* Name of the module */ 4926 const sqlite3_module *p, /* Methods for the module */ 4927 void *pClientData /* Client data for xCreate/xConnect */ 4928 ); 4929 SQLITE_API int sqlite3_create_module_v2( 4930 sqlite3 *db, /* SQLite connection to register module with */ 4931 const char *zName, /* Name of the module */ 4932 const sqlite3_module *p, /* Methods for the module */ 4933 void *pClientData, /* Client data for xCreate/xConnect */ 4934 void(*xDestroy)(void*) /* Module destructor function */ 4935 ); 4936 4937 /* 4938 ** CAPI3REF: Virtual Table Instance Object 4939 ** KEYWORDS: sqlite3_vtab 4940 ** 4941 ** Every [virtual table module] implementation uses a subclass 4942 ** of this object to describe a particular instance 4943 ** of the [virtual table]. Each subclass will 4944 ** be tailored to the specific needs of the module implementation. 4945 ** The purpose of this superclass is to define certain fields that are 4946 ** common to all module implementations. 4947 ** 4948 ** ^Virtual tables methods can set an error message by assigning a 4949 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 4950 ** take care that any prior string is freed by a call to [sqlite3_free()] 4951 ** prior to assigning a new string to zErrMsg. ^After the error message 4952 ** is delivered up to the client application, the string will be automatically 4953 ** freed by sqlite3_free() and the zErrMsg field will be zeroed. 4954 */ 4955 struct sqlite3_vtab { 4956 const sqlite3_module *pModule; /* The module for this virtual table */ 4957 int nRef; /* NO LONGER USED */ 4958 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 4959 /* Virtual table implementations will typically add additional fields */ 4960 }; 4961 4962 /* 4963 ** CAPI3REF: Virtual Table Cursor Object 4964 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 4965 ** 4966 ** Every [virtual table module] implementation uses a subclass of the 4967 ** following structure to describe cursors that point into the 4968 ** [virtual table] and are used 4969 ** to loop through the virtual table. Cursors are created using the 4970 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 4971 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used 4972 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 4973 ** of the module. Each module implementation will define 4974 ** the content of a cursor structure to suit its own needs. 4975 ** 4976 ** This superclass exists in order to define fields of the cursor that 4977 ** are common to all implementations. 4978 */ 4979 struct sqlite3_vtab_cursor { 4980 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 4981 /* Virtual table implementations will typically add additional fields */ 4982 }; 4983 4984 /* 4985 ** CAPI3REF: Declare The Schema Of A Virtual Table 4986 ** 4987 ** ^The [xCreate] and [xConnect] methods of a 4988 ** [virtual table module] call this interface 4989 ** to declare the format (the names and datatypes of the columns) of 4990 ** the virtual tables they implement. 4991 */ 4992 SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 4993 4994 /* 4995 ** CAPI3REF: Overload A Function For A Virtual Table 4996 ** 4997 ** ^(Virtual tables can provide alternative implementations of functions 4998 ** using the [xFindFunction] method of the [virtual table module]. 4999 ** But global versions of those functions 5000 ** must exist in order to be overloaded.)^ 5001 ** 5002 ** ^(This API makes sure a global version of a function with a particular 5003 ** name and number of parameters exists. If no such function exists 5004 ** before this API is called, a new function is created.)^ ^The implementation 5005 ** of the new function always causes an exception to be thrown. So 5006 ** the new function is not good for anything by itself. Its only 5007 ** purpose is to be a placeholder function that can be overloaded 5008 ** by a [virtual table]. 5009 */ 5010 SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5011 5012 /* 5013 ** The interface to the virtual-table mechanism defined above (back up 5014 ** to a comment remarkably similar to this one) is currently considered 5015 ** to be experimental. The interface might change in incompatible ways. 5016 ** If this is a problem for you, do not use the interface at this time. 5017 ** 5018 ** When the virtual-table mechanism stabilizes, we will declare the 5019 ** interface fixed, support it indefinitely, and remove this comment. 5020 */ 5021 5022 /* 5023 ** CAPI3REF: A Handle To An Open BLOB 5024 ** KEYWORDS: {BLOB handle} {BLOB handles} 5025 ** 5026 ** An instance of this object represents an open BLOB on which 5027 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5028 ** ^Objects of this type are created by [sqlite3_blob_open()] 5029 ** and destroyed by [sqlite3_blob_close()]. 5030 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5031 ** can be used to read or write small subsections of the BLOB. 5032 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5033 */ 5034 typedef struct sqlite3_blob sqlite3_blob; 5035 5036 /* 5037 ** CAPI3REF: Open A BLOB For Incremental I/O 5038 ** 5039 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5040 ** in row iRow, column zColumn, table zTable in database zDb; 5041 ** in other words, the same BLOB that would be selected by: 5042 ** 5043 ** <pre> 5044 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5045 ** </pre>)^ 5046 ** 5047 ** ^If the flags parameter is non-zero, then the BLOB is opened for read 5048 ** and write access. ^If it is zero, the BLOB is opened for read access. 5049 ** ^It is not possible to open a column that is part of an index or primary 5050 ** key for writing. ^If [foreign key constraints] are enabled, it is 5051 ** not possible to open a column that is part of a [child key] for writing. 5052 ** 5053 ** ^Note that the database name is not the filename that contains 5054 ** the database but rather the symbolic name of the database that 5055 ** appears after the AS keyword when the database is connected using [ATTACH]. 5056 ** ^For the main database file, the database name is "main". 5057 ** ^For TEMP tables, the database name is "temp". 5058 ** 5059 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 5060 ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 5061 ** to be a null pointer.)^ 5062 ** ^This function sets the [database connection] error code and message 5063 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 5064 ** functions. ^Note that the *ppBlob variable is always initialized in a 5065 ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 5066 ** regardless of the success or failure of this routine. 5067 ** 5068 ** ^(If the row that a BLOB handle points to is modified by an 5069 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5070 ** then the BLOB handle is marked as "expired". 5071 ** This is true if any column of the row is changed, even a column 5072 ** other than the one the BLOB handle is open on.)^ 5073 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5074 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5075 ** ^(Changes written into a BLOB prior to the BLOB expiring are not 5076 ** rolled back by the expiration of the BLOB. Such changes will eventually 5077 ** commit if the transaction continues to completion.)^ 5078 ** 5079 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5080 ** the opened blob. ^The size of a blob may not be changed by this 5081 ** interface. Use the [UPDATE] SQL command to change the size of a 5082 ** blob. 5083 ** 5084 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5085 ** and the built-in [zeroblob] SQL function can be used, if desired, 5086 ** to create an empty, zero-filled blob in which to read or write using 5087 ** this interface. 5088 ** 5089 ** To avoid a resource leak, every open [BLOB handle] should eventually 5090 ** be released by a call to [sqlite3_blob_close()]. 5091 */ 5092 SQLITE_API int sqlite3_blob_open( 5093 sqlite3*, 5094 const char *zDb, 5095 const char *zTable, 5096 const char *zColumn, 5097 sqlite3_int64 iRow, 5098 int flags, 5099 sqlite3_blob **ppBlob 5100 ); 5101 5102 /* 5103 ** CAPI3REF: Move a BLOB Handle to a New Row 5104 ** 5105 ** ^This function is used to move an existing blob handle so that it points 5106 ** to a different row of the same database table. ^The new row is identified 5107 ** by the rowid value passed as the second argument. Only the row can be 5108 ** changed. ^The database, table and column on which the blob handle is open 5109 ** remain the same. Moving an existing blob handle to a new row can be 5110 ** faster than closing the existing handle and opening a new one. 5111 ** 5112 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5113 ** it must exist and there must be either a blob or text value stored in 5114 ** the nominated column.)^ ^If the new row is not present in the table, or if 5115 ** it does not contain a blob or text value, or if another error occurs, an 5116 ** SQLite error code is returned and the blob handle is considered aborted. 5117 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5118 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5119 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5120 ** always returns zero. 5121 ** 5122 ** ^This function sets the database handle error code and message. 5123 */ 5124 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5125 5126 /* 5127 ** CAPI3REF: Close A BLOB Handle 5128 ** 5129 ** ^Closes an open [BLOB handle]. 5130 ** 5131 ** ^Closing a BLOB shall cause the current transaction to commit 5132 ** if there are no other BLOBs, no pending prepared statements, and the 5133 ** database connection is in [autocommit mode]. 5134 ** ^If any writes were made to the BLOB, they might be held in cache 5135 ** until the close operation if they will fit. 5136 ** 5137 ** ^(Closing the BLOB often forces the changes 5138 ** out to disk and so if any I/O errors occur, they will likely occur 5139 ** at the time when the BLOB is closed. Any errors that occur during 5140 ** closing are reported as a non-zero return value.)^ 5141 ** 5142 ** ^(The BLOB is closed unconditionally. Even if this routine returns 5143 ** an error code, the BLOB is still closed.)^ 5144 ** 5145 ** ^Calling this routine with a null pointer (such as would be returned 5146 ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 5147 */ 5148 SQLITE_API int sqlite3_blob_close(sqlite3_blob *); 5149 5150 /* 5151 ** CAPI3REF: Return The Size Of An Open BLOB 5152 ** 5153 ** ^Returns the size in bytes of the BLOB accessible via the 5154 ** successfully opened [BLOB handle] in its only argument. ^The 5155 ** incremental blob I/O routines can only read or overwriting existing 5156 ** blob content; they cannot change the size of a blob. 5157 ** 5158 ** This routine only works on a [BLOB handle] which has been created 5159 ** by a prior successful call to [sqlite3_blob_open()] and which has not 5160 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5161 ** to this routine results in undefined and probably undesirable behavior. 5162 */ 5163 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *); 5164 5165 /* 5166 ** CAPI3REF: Read Data From A BLOB Incrementally 5167 ** 5168 ** ^(This function is used to read data from an open [BLOB handle] into a 5169 ** caller-supplied buffer. N bytes of data are copied into buffer Z 5170 ** from the open BLOB, starting at offset iOffset.)^ 5171 ** 5172 ** ^If offset iOffset is less than N bytes from the end of the BLOB, 5173 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 5174 ** less than zero, [SQLITE_ERROR] is returned and no data is read. 5175 ** ^The size of the blob (and hence the maximum value of N+iOffset) 5176 ** can be determined using the [sqlite3_blob_bytes()] interface. 5177 ** 5178 ** ^An attempt to read from an expired [BLOB handle] fails with an 5179 ** error code of [SQLITE_ABORT]. 5180 ** 5181 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 5182 ** Otherwise, an [error code] or an [extended error code] is returned.)^ 5183 ** 5184 ** This routine only works on a [BLOB handle] which has been created 5185 ** by a prior successful call to [sqlite3_blob_open()] and which has not 5186 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5187 ** to this routine results in undefined and probably undesirable behavior. 5188 ** 5189 ** See also: [sqlite3_blob_write()]. 5190 */ 5191 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 5192 5193 /* 5194 ** CAPI3REF: Write Data Into A BLOB Incrementally 5195 ** 5196 ** ^This function is used to write data into an open [BLOB handle] from a 5197 ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 5198 ** into the open BLOB, starting at offset iOffset. 5199 ** 5200 ** ^If the [BLOB handle] passed as the first argument was not opened for 5201 ** writing (the flags parameter to [sqlite3_blob_open()] was zero), 5202 ** this function returns [SQLITE_READONLY]. 5203 ** 5204 ** ^This function may only modify the contents of the BLOB; it is 5205 ** not possible to increase the size of a BLOB using this API. 5206 ** ^If offset iOffset is less than N bytes from the end of the BLOB, 5207 ** [SQLITE_ERROR] is returned and no data is written. ^If N is 5208 ** less than zero [SQLITE_ERROR] is returned and no data is written. 5209 ** The size of the BLOB (and hence the maximum value of N+iOffset) 5210 ** can be determined using the [sqlite3_blob_bytes()] interface. 5211 ** 5212 ** ^An attempt to write to an expired [BLOB handle] fails with an 5213 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 5214 ** before the [BLOB handle] expired are not rolled back by the 5215 ** expiration of the handle, though of course those changes might 5216 ** have been overwritten by the statement that expired the BLOB handle 5217 ** or by other independent statements. 5218 ** 5219 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 5220 ** Otherwise, an [error code] or an [extended error code] is returned.)^ 5221 ** 5222 ** This routine only works on a [BLOB handle] which has been created 5223 ** by a prior successful call to [sqlite3_blob_open()] and which has not 5224 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5225 ** to this routine results in undefined and probably undesirable behavior. 5226 ** 5227 ** See also: [sqlite3_blob_read()]. 5228 */ 5229 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 5230 5231 /* 5232 ** CAPI3REF: Virtual File System Objects 5233 ** 5234 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object 5235 ** that SQLite uses to interact 5236 ** with the underlying operating system. Most SQLite builds come with a 5237 ** single default VFS that is appropriate for the host computer. 5238 ** New VFSes can be registered and existing VFSes can be unregistered. 5239 ** The following interfaces are provided. 5240 ** 5241 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 5242 ** ^Names are case sensitive. 5243 ** ^Names are zero-terminated UTF-8 strings. 5244 ** ^If there is no match, a NULL pointer is returned. 5245 ** ^If zVfsName is NULL then the default VFS is returned. 5246 ** 5247 ** ^New VFSes are registered with sqlite3_vfs_register(). 5248 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 5249 ** ^The same VFS can be registered multiple times without injury. 5250 ** ^To make an existing VFS into the default VFS, register it again 5251 ** with the makeDflt flag set. If two different VFSes with the 5252 ** same name are registered, the behavior is undefined. If a 5253 ** VFS is registered with a name that is NULL or an empty string, 5254 ** then the behavior is undefined. 5255 ** 5256 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 5257 ** ^(If the default VFS is unregistered, another VFS is chosen as 5258 ** the default. The choice for the new VFS is arbitrary.)^ 5259 */ 5260 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 5261 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 5262 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*); 5263 5264 /* 5265 ** CAPI3REF: Mutexes 5266 ** 5267 ** The SQLite core uses these routines for thread 5268 ** synchronization. Though they are intended for internal 5269 ** use by SQLite, code that links against SQLite is 5270 ** permitted to use any of these routines. 5271 ** 5272 ** The SQLite source code contains multiple implementations 5273 ** of these mutex routines. An appropriate implementation 5274 ** is selected automatically at compile-time. ^(The following 5275 ** implementations are available in the SQLite core: 5276 ** 5277 ** <ul> 5278 ** <li> SQLITE_MUTEX_OS2 5279 ** <li> SQLITE_MUTEX_PTHREAD 5280 ** <li> SQLITE_MUTEX_W32 5281 ** <li> SQLITE_MUTEX_NOOP 5282 ** </ul>)^ 5283 ** 5284 ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 5285 ** that does no real locking and is appropriate for use in 5286 ** a single-threaded application. ^The SQLITE_MUTEX_OS2, 5287 ** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations 5288 ** are appropriate for use on OS/2, Unix, and Windows. 5289 ** 5290 ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 5291 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 5292 ** implementation is included with the library. In this case the 5293 ** application must supply a custom mutex implementation using the 5294 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 5295 ** before calling sqlite3_initialize() or any other public sqlite3_ 5296 ** function that calls sqlite3_initialize().)^ 5297 ** 5298 ** ^The sqlite3_mutex_alloc() routine allocates a new 5299 ** mutex and returns a pointer to it. ^If it returns NULL 5300 ** that means that a mutex could not be allocated. ^SQLite 5301 ** will unwind its stack and return an error. ^(The argument 5302 ** to sqlite3_mutex_alloc() is one of these integer constants: 5303 ** 5304 ** <ul> 5305 ** <li> SQLITE_MUTEX_FAST 5306 ** <li> SQLITE_MUTEX_RECURSIVE 5307 ** <li> SQLITE_MUTEX_STATIC_MASTER 5308 ** <li> SQLITE_MUTEX_STATIC_MEM 5309 ** <li> SQLITE_MUTEX_STATIC_MEM2 5310 ** <li> SQLITE_MUTEX_STATIC_PRNG 5311 ** <li> SQLITE_MUTEX_STATIC_LRU 5312 ** <li> SQLITE_MUTEX_STATIC_LRU2 5313 ** </ul>)^ 5314 ** 5315 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 5316 ** cause sqlite3_mutex_alloc() to create 5317 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 5318 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 5319 ** The mutex implementation does not need to make a distinction 5320 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 5321 ** not want to. ^SQLite will only request a recursive mutex in 5322 ** cases where it really needs one. ^If a faster non-recursive mutex 5323 ** implementation is available on the host platform, the mutex subsystem 5324 ** might return such a mutex in response to SQLITE_MUTEX_FAST. 5325 ** 5326 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 5327 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 5328 ** a pointer to a static preexisting mutex. ^Six static mutexes are 5329 ** used by the current version of SQLite. Future versions of SQLite 5330 ** may add additional static mutexes. Static mutexes are for internal 5331 ** use by SQLite only. Applications that use SQLite mutexes should 5332 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 5333 ** SQLITE_MUTEX_RECURSIVE. 5334 ** 5335 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 5336 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 5337 ** returns a different mutex on every call. ^But for the static 5338 ** mutex types, the same mutex is returned on every call that has 5339 ** the same type number. 5340 ** 5341 ** ^The sqlite3_mutex_free() routine deallocates a previously 5342 ** allocated dynamic mutex. ^SQLite is careful to deallocate every 5343 ** dynamic mutex that it allocates. The dynamic mutexes must not be in 5344 ** use when they are deallocated. Attempting to deallocate a static 5345 ** mutex results in undefined behavior. ^SQLite never deallocates 5346 ** a static mutex. 5347 ** 5348 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 5349 ** to enter a mutex. ^If another thread is already within the mutex, 5350 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 5351 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 5352 ** upon successful entry. ^(Mutexes created using 5353 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 5354 ** In such cases the, 5355 ** mutex must be exited an equal number of times before another thread 5356 ** can enter.)^ ^(If the same thread tries to enter any other 5357 ** kind of mutex more than once, the behavior is undefined. 5358 ** SQLite will never exhibit 5359 ** such behavior in its own use of mutexes.)^ 5360 ** 5361 ** ^(Some systems (for example, Windows 95) do not support the operation 5362 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 5363 ** will always return SQLITE_BUSY. The SQLite core only ever uses 5364 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 5365 ** 5366 ** ^The sqlite3_mutex_leave() routine exits a mutex that was 5367 ** previously entered by the same thread. ^(The behavior 5368 ** is undefined if the mutex is not currently entered by the 5369 ** calling thread or is not currently allocated. SQLite will 5370 ** never do either.)^ 5371 ** 5372 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 5373 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines 5374 ** behave as no-ops. 5375 ** 5376 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 5377 */ 5378 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int); 5379 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*); 5380 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*); 5381 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*); 5382 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*); 5383 5384 /* 5385 ** CAPI3REF: Mutex Methods Object 5386 ** 5387 ** An instance of this structure defines the low-level routines 5388 ** used to allocate and use mutexes. 5389 ** 5390 ** Usually, the default mutex implementations provided by SQLite are 5391 ** sufficient, however the user has the option of substituting a custom 5392 ** implementation for specialized deployments or systems for which SQLite 5393 ** does not provide a suitable implementation. In this case, the user 5394 ** creates and populates an instance of this structure to pass 5395 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 5396 ** Additionally, an instance of this structure can be used as an 5397 ** output variable when querying the system for the current mutex 5398 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 5399 ** 5400 ** ^The xMutexInit method defined by this structure is invoked as 5401 ** part of system initialization by the sqlite3_initialize() function. 5402 ** ^The xMutexInit routine is called by SQLite exactly once for each 5403 ** effective call to [sqlite3_initialize()]. 5404 ** 5405 ** ^The xMutexEnd method defined by this structure is invoked as 5406 ** part of system shutdown by the sqlite3_shutdown() function. The 5407 ** implementation of this method is expected to release all outstanding 5408 ** resources obtained by the mutex methods implementation, especially 5409 ** those obtained by the xMutexInit method. ^The xMutexEnd() 5410 ** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 5411 ** 5412 ** ^(The remaining seven methods defined by this structure (xMutexAlloc, 5413 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 5414 ** xMutexNotheld) implement the following interfaces (respectively): 5415 ** 5416 ** <ul> 5417 ** <li> [sqlite3_mutex_alloc()] </li> 5418 ** <li> [sqlite3_mutex_free()] </li> 5419 ** <li> [sqlite3_mutex_enter()] </li> 5420 ** <li> [sqlite3_mutex_try()] </li> 5421 ** <li> [sqlite3_mutex_leave()] </li> 5422 ** <li> [sqlite3_mutex_held()] </li> 5423 ** <li> [sqlite3_mutex_notheld()] </li> 5424 ** </ul>)^ 5425 ** 5426 ** The only difference is that the public sqlite3_XXX functions enumerated 5427 ** above silently ignore any invocations that pass a NULL pointer instead 5428 ** of a valid mutex handle. The implementations of the methods defined 5429 ** by this structure are not required to handle this case, the results 5430 ** of passing a NULL pointer instead of a valid mutex handle are undefined 5431 ** (i.e. it is acceptable to provide an implementation that segfaults if 5432 ** it is passed a NULL pointer). 5433 ** 5434 ** The xMutexInit() method must be threadsafe. ^It must be harmless to 5435 ** invoke xMutexInit() multiple times within the same process and without 5436 ** intervening calls to xMutexEnd(). Second and subsequent calls to 5437 ** xMutexInit() must be no-ops. 5438 ** 5439 ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 5440 ** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 5441 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 5442 ** memory allocation for a fast or recursive mutex. 5443 ** 5444 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 5445 ** called, but only if the prior call to xMutexInit returned SQLITE_OK. 5446 ** If xMutexInit fails in any way, it is expected to clean up after itself 5447 ** prior to returning. 5448 */ 5449 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 5450 struct sqlite3_mutex_methods { 5451 int (*xMutexInit)(void); 5452 int (*xMutexEnd)(void); 5453 sqlite3_mutex *(*xMutexAlloc)(int); 5454 void (*xMutexFree)(sqlite3_mutex *); 5455 void (*xMutexEnter)(sqlite3_mutex *); 5456 int (*xMutexTry)(sqlite3_mutex *); 5457 void (*xMutexLeave)(sqlite3_mutex *); 5458 int (*xMutexHeld)(sqlite3_mutex *); 5459 int (*xMutexNotheld)(sqlite3_mutex *); 5460 }; 5461 5462 /* 5463 ** CAPI3REF: Mutex Verification Routines 5464 ** 5465 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 5466 ** are intended for use inside assert() statements. ^The SQLite core 5467 ** never uses these routines except inside an assert() and applications 5468 ** are advised to follow the lead of the core. ^The SQLite core only 5469 ** provides implementations for these routines when it is compiled 5470 ** with the SQLITE_DEBUG flag. ^External mutex implementations 5471 ** are only required to provide these routines if SQLITE_DEBUG is 5472 ** defined and if NDEBUG is not defined. 5473 ** 5474 ** ^These routines should return true if the mutex in their argument 5475 ** is held or not held, respectively, by the calling thread. 5476 ** 5477 ** ^The implementation is not required to provided versions of these 5478 ** routines that actually work. If the implementation does not provide working 5479 ** versions of these routines, it should at least provide stubs that always 5480 ** return true so that one does not get spurious assertion failures. 5481 ** 5482 ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 5483 ** the routine should return 1. This seems counter-intuitive since 5484 ** clearly the mutex cannot be held if it does not exist. But 5485 ** the reason the mutex does not exist is because the build is not 5486 ** using mutexes. And we do not want the assert() containing the 5487 ** call to sqlite3_mutex_held() to fail, so a non-zero return is 5488 ** the appropriate thing to do. ^The sqlite3_mutex_notheld() 5489 ** interface should also return 1 when given a NULL pointer. 5490 */ 5491 #ifndef NDEBUG 5492 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*); 5493 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*); 5494 #endif 5495 5496 /* 5497 ** CAPI3REF: Mutex Types 5498 ** 5499 ** The [sqlite3_mutex_alloc()] interface takes a single argument 5500 ** which is one of these integer constants. 5501 ** 5502 ** The set of static mutexes may change from one SQLite release to the 5503 ** next. Applications that override the built-in mutex logic must be 5504 ** prepared to accommodate additional static mutexes. 5505 */ 5506 #define SQLITE_MUTEX_FAST 0 5507 #define SQLITE_MUTEX_RECURSIVE 1 5508 #define SQLITE_MUTEX_STATIC_MASTER 2 5509 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 5510 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 5511 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 5512 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 5513 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 5514 #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 5515 #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 5516 5517 /* 5518 ** CAPI3REF: Retrieve the mutex for a database connection 5519 ** 5520 ** ^This interface returns a pointer the [sqlite3_mutex] object that 5521 ** serializes access to the [database connection] given in the argument 5522 ** when the [threading mode] is Serialized. 5523 ** ^If the [threading mode] is Single-thread or Multi-thread then this 5524 ** routine returns a NULL pointer. 5525 */ 5526 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 5527 5528 /* 5529 ** CAPI3REF: Low-Level Control Of Database Files 5530 ** 5531 ** ^The [sqlite3_file_control()] interface makes a direct call to the 5532 ** xFileControl method for the [sqlite3_io_methods] object associated 5533 ** with a particular database identified by the second argument. ^The 5534 ** name of the database is "main" for the main database or "temp" for the 5535 ** TEMP database, or the name that appears after the AS keyword for 5536 ** databases that are added using the [ATTACH] SQL command. 5537 ** ^A NULL pointer can be used in place of "main" to refer to the 5538 ** main database file. 5539 ** ^The third and fourth parameters to this routine 5540 ** are passed directly through to the second and third parameters of 5541 ** the xFileControl method. ^The return value of the xFileControl 5542 ** method becomes the return value of this routine. 5543 ** 5544 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 5545 ** a pointer to the underlying [sqlite3_file] object to be written into 5546 ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 5547 ** case is a short-circuit path which does not actually invoke the 5548 ** underlying sqlite3_io_methods.xFileControl method. 5549 ** 5550 ** ^If the second parameter (zDbName) does not match the name of any 5551 ** open database file, then SQLITE_ERROR is returned. ^This error 5552 ** code is not remembered and will not be recalled by [sqlite3_errcode()] 5553 ** or [sqlite3_errmsg()]. The underlying xFileControl method might 5554 ** also return SQLITE_ERROR. There is no way to distinguish between 5555 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5556 ** xFileControl method. 5557 ** 5558 ** See also: [SQLITE_FCNTL_LOCKSTATE] 5559 */ 5560 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5561 5562 /* 5563 ** CAPI3REF: Testing Interface 5564 ** 5565 ** ^The sqlite3_test_control() interface is used to read out internal 5566 ** state of SQLite and to inject faults into SQLite for testing 5567 ** purposes. ^The first parameter is an operation code that determines 5568 ** the number, meaning, and operation of all subsequent parameters. 5569 ** 5570 ** This interface is not for use by applications. It exists solely 5571 ** for verifying the correct operation of the SQLite library. Depending 5572 ** on how the SQLite library is compiled, this interface might not exist. 5573 ** 5574 ** The details of the operation codes, their meanings, the parameters 5575 ** they take, and what they do are all subject to change without notice. 5576 ** Unlike most of the SQLite API, this function is not guaranteed to 5577 ** operate consistently from one release to the next. 5578 */ 5579 SQLITE_API int sqlite3_test_control(int op, ...); 5580 5581 /* 5582 ** CAPI3REF: Testing Interface Operation Codes 5583 ** 5584 ** These constants are the valid operation code parameters used 5585 ** as the first argument to [sqlite3_test_control()]. 5586 ** 5587 ** These parameters and their meanings are subject to change 5588 ** without notice. These values are for testing purposes only. 5589 ** Applications should not use any of these parameters or the 5590 ** [sqlite3_test_control()] interface. 5591 */ 5592 #define SQLITE_TESTCTRL_FIRST 5 5593 #define SQLITE_TESTCTRL_PRNG_SAVE 5 5594 #define SQLITE_TESTCTRL_PRNG_RESTORE 6 5595 #define SQLITE_TESTCTRL_PRNG_RESET 7 5596 #define SQLITE_TESTCTRL_BITVEC_TEST 8 5597 #define SQLITE_TESTCTRL_FAULT_INSTALL 9 5598 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5599 #define SQLITE_TESTCTRL_PENDING_BYTE 11 5600 #define SQLITE_TESTCTRL_ASSERT 12 5601 #define SQLITE_TESTCTRL_ALWAYS 13 5602 #define SQLITE_TESTCTRL_RESERVE 14 5603 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15 5604 #define SQLITE_TESTCTRL_ISKEYWORD 16 5605 #define SQLITE_TESTCTRL_PGHDRSZ 17 5606 #define SQLITE_TESTCTRL_SCRATCHMALLOC 18 5607 #define SQLITE_TESTCTRL_LOCALTIME_FAULT 19 5608 #define SQLITE_TESTCTRL_LAST 19 5609 5610 /* 5611 ** CAPI3REF: SQLite Runtime Status 5612 ** 5613 ** ^This interface is used to retrieve runtime status information 5614 ** about the performance of SQLite, and optionally to reset various 5615 ** highwater marks. ^The first argument is an integer code for 5616 ** the specific parameter to measure. ^(Recognized integer codes 5617 ** are of the form [status parameters | SQLITE_STATUS_...].)^ 5618 ** ^The current value of the parameter is returned into *pCurrent. 5619 ** ^The highest recorded value is returned in *pHighwater. ^If the 5620 ** resetFlag is true, then the highest record value is reset after 5621 ** *pHighwater is written. ^(Some parameters do not record the highest 5622 ** value. For those parameters 5623 ** nothing is written into *pHighwater and the resetFlag is ignored.)^ 5624 ** ^(Other parameters record only the highwater mark and not the current 5625 ** value. For these latter parameters nothing is written into *pCurrent.)^ 5626 ** 5627 ** ^The sqlite3_status() routine returns SQLITE_OK on success and a 5628 ** non-zero [error code] on failure. 5629 ** 5630 ** This routine is threadsafe but is not atomic. This routine can be 5631 ** called while other threads are running the same or different SQLite 5632 ** interfaces. However the values returned in *pCurrent and 5633 ** *pHighwater reflect the status of SQLite at different points in time 5634 ** and it is possible that another thread might change the parameter 5635 ** in between the times when *pCurrent and *pHighwater are written. 5636 ** 5637 ** See also: [sqlite3_db_status()] 5638 */ 5639 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 5640 5641 5642 /* 5643 ** CAPI3REF: Status Parameters 5644 ** KEYWORDS: {status parameters} 5645 ** 5646 ** These integer constants designate various run-time status parameters 5647 ** that can be returned by [sqlite3_status()]. 5648 ** 5649 ** <dl> 5650 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 5651 ** <dd>This parameter is the current amount of memory checked out 5652 ** using [sqlite3_malloc()], either directly or indirectly. The 5653 ** figure includes calls made to [sqlite3_malloc()] by the application 5654 ** and internal memory usage by the SQLite library. Scratch memory 5655 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 5656 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 5657 ** this parameter. The amount returned is the sum of the allocation 5658 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 5659 ** 5660 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 5661 ** <dd>This parameter records the largest memory allocation request 5662 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 5663 ** internal equivalents). Only the value returned in the 5664 ** *pHighwater parameter to [sqlite3_status()] is of interest. 5665 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 5666 ** 5667 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 5668 ** <dd>This parameter records the number of separate memory allocations 5669 ** currently checked out.</dd>)^ 5670 ** 5671 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 5672 ** <dd>This parameter returns the number of pages used out of the 5673 ** [pagecache memory allocator] that was configured using 5674 ** [SQLITE_CONFIG_PAGECACHE]. The 5675 ** value returned is in pages, not in bytes.</dd>)^ 5676 ** 5677 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 5678 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5679 ** <dd>This parameter returns the number of bytes of page cache 5680 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 5681 ** buffer and where forced to overflow to [sqlite3_malloc()]. The 5682 ** returned value includes allocations that overflowed because they 5683 ** where too large (they were larger than the "sz" parameter to 5684 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 5685 ** no space was left in the page cache.</dd>)^ 5686 ** 5687 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 5688 ** <dd>This parameter records the largest memory allocation request 5689 ** handed to [pagecache memory allocator]. Only the value returned in the 5690 ** *pHighwater parameter to [sqlite3_status()] is of interest. 5691 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 5692 ** 5693 ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 5694 ** <dd>This parameter returns the number of allocations used out of the 5695 ** [scratch memory allocator] configured using 5696 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5697 ** in bytes. Since a single thread may only have one scratch allocation 5698 ** outstanding at time, this parameter also reports the number of threads 5699 ** using scratch memory at the same time.</dd>)^ 5700 ** 5701 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5702 ** <dd>This parameter returns the number of bytes of scratch memory 5703 ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 5704 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5705 ** returned include overflows because the requested allocation was too 5706 ** larger (that is, because the requested allocation was larger than the 5707 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5708 ** slots were available. 5709 ** </dd>)^ 5710 ** 5711 ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5712 ** <dd>This parameter records the largest memory allocation request 5713 ** handed to [scratch memory allocator]. Only the value returned in the 5714 ** *pHighwater parameter to [sqlite3_status()] is of interest. 5715 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 5716 ** 5717 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 5718 ** <dd>This parameter records the deepest parser stack. It is only 5719 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 5720 ** </dl> 5721 ** 5722 ** New status parameters may be added from time to time. 5723 */ 5724 #define SQLITE_STATUS_MEMORY_USED 0 5725 #define SQLITE_STATUS_PAGECACHE_USED 1 5726 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5727 #define SQLITE_STATUS_SCRATCH_USED 3 5728 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5729 #define SQLITE_STATUS_MALLOC_SIZE 5 5730 #define SQLITE_STATUS_PARSER_STACK 6 5731 #define SQLITE_STATUS_PAGECACHE_SIZE 7 5732 #define SQLITE_STATUS_SCRATCH_SIZE 8 5733 #define SQLITE_STATUS_MALLOC_COUNT 9 5734 5735 /* 5736 ** CAPI3REF: Database Connection Status 5737 ** 5738 ** ^This interface is used to retrieve runtime status information 5739 ** about a single [database connection]. ^The first argument is the 5740 ** database connection object to be interrogated. ^The second argument 5741 ** is an integer constant, taken from the set of 5742 ** [SQLITE_DBSTATUS options], that 5743 ** determines the parameter to interrogate. The set of 5744 ** [SQLITE_DBSTATUS options] is likely 5745 ** to grow in future releases of SQLite. 5746 ** 5747 ** ^The current value of the requested parameter is written into *pCur 5748 ** and the highest instantaneous value is written into *pHiwtr. ^If 5749 ** the resetFlg is true, then the highest instantaneous value is 5750 ** reset back down to the current value. 5751 ** 5752 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 5753 ** non-zero [error code] on failure. 5754 ** 5755 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5756 */ 5757 SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5758 5759 /* 5760 ** CAPI3REF: Status Parameters for database connections 5761 ** KEYWORDS: {SQLITE_DBSTATUS options} 5762 ** 5763 ** These constants are the available integer "verbs" that can be passed as 5764 ** the second argument to the [sqlite3_db_status()] interface. 5765 ** 5766 ** New verbs may be added in future releases of SQLite. Existing verbs 5767 ** might be discontinued. Applications should check the return code from 5768 ** [sqlite3_db_status()] to make sure that the call worked. 5769 ** The [sqlite3_db_status()] interface will return a non-zero error code 5770 ** if a discontinued or unsupported verb is invoked. 5771 ** 5772 ** <dl> 5773 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5774 ** <dd>This parameter returns the number of lookaside memory slots currently 5775 ** checked out.</dd>)^ 5776 ** 5777 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 5778 ** <dd>This parameter returns the number malloc attempts that were 5779 ** satisfied using lookaside memory. Only the high-water value is meaningful; 5780 ** the current value is always zero.)^ 5781 ** 5782 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 5783 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 5784 ** <dd>This parameter returns the number malloc attempts that might have 5785 ** been satisfied using lookaside memory but failed due to the amount of 5786 ** memory requested being larger than the lookaside slot size. 5787 ** Only the high-water value is meaningful; 5788 ** the current value is always zero.)^ 5789 ** 5790 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 5791 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 5792 ** <dd>This parameter returns the number malloc attempts that might have 5793 ** been satisfied using lookaside memory but failed due to all lookaside 5794 ** memory already being in use. 5795 ** Only the high-water value is meaningful; 5796 ** the current value is always zero.)^ 5797 ** 5798 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 5799 ** <dd>This parameter returns the approximate number of of bytes of heap 5800 ** memory used by all pager caches associated with the database connection.)^ 5801 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 5802 ** 5803 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 5804 ** <dd>This parameter returns the approximate number of of bytes of heap 5805 ** memory used to store the schema for all databases associated 5806 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 5807 ** ^The full amount of memory used by the schemas is reported, even if the 5808 ** schema memory is shared with other database connections due to 5809 ** [shared cache mode] being enabled. 5810 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 5811 ** 5812 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 5813 ** <dd>This parameter returns the approximate number of of bytes of heap 5814 ** and lookaside memory used by all prepared statements associated with 5815 ** the database connection.)^ 5816 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 5817 ** </dd> 5818 ** </dl> 5819 */ 5820 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0 5821 #define SQLITE_DBSTATUS_CACHE_USED 1 5822 #define SQLITE_DBSTATUS_SCHEMA_USED 2 5823 #define SQLITE_DBSTATUS_STMT_USED 3 5824 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 5825 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 5826 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 5827 #define SQLITE_DBSTATUS_MAX 6 /* Largest defined DBSTATUS */ 5828 5829 5830 /* 5831 ** CAPI3REF: Prepared Statement Status 5832 ** 5833 ** ^(Each prepared statement maintains various 5834 ** [SQLITE_STMTSTATUS counters] that measure the number 5835 ** of times it has performed specific operations.)^ These counters can 5836 ** be used to monitor the performance characteristics of the prepared 5837 ** statements. For example, if the number of table steps greatly exceeds 5838 ** the number of table searches or result rows, that would tend to indicate 5839 ** that the prepared statement is using a full table scan rather than 5840 ** an index. 5841 ** 5842 ** ^(This interface is used to retrieve and reset counter values from 5843 ** a [prepared statement]. The first argument is the prepared statement 5844 ** object to be interrogated. The second argument 5845 ** is an integer code for a specific [SQLITE_STMTSTATUS counter] 5846 ** to be interrogated.)^ 5847 ** ^The current value of the requested counter is returned. 5848 ** ^If the resetFlg is true, then the counter is reset to zero after this 5849 ** interface call returns. 5850 ** 5851 ** See also: [sqlite3_status()] and [sqlite3_db_status()]. 5852 */ 5853 SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 5854 5855 /* 5856 ** CAPI3REF: Status Parameters for prepared statements 5857 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 5858 ** 5859 ** These preprocessor macros define integer codes that name counter 5860 ** values associated with the [sqlite3_stmt_status()] interface. 5861 ** The meanings of the various counters are as follows: 5862 ** 5863 ** <dl> 5864 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 5865 ** <dd>^This is the number of times that SQLite has stepped forward in 5866 ** a table as part of a full table scan. Large numbers for this counter 5867 ** may indicate opportunities for performance improvement through 5868 ** careful use of indices.</dd> 5869 ** 5870 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 5871 ** <dd>^This is the number of sort operations that have occurred. 5872 ** A non-zero value in this counter may indicate an opportunity to 5873 ** improvement performance through careful use of indices.</dd> 5874 ** 5875 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 5876 ** <dd>^This is the number of rows inserted into transient indices that 5877 ** were created automatically in order to help joins run faster. 5878 ** A non-zero value in this counter may indicate an opportunity to 5879 ** improvement performance by adding permanent indices that do not 5880 ** need to be reinitialized each time the statement is run.</dd> 5881 ** 5882 ** </dl> 5883 */ 5884 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 5885 #define SQLITE_STMTSTATUS_SORT 2 5886 #define SQLITE_STMTSTATUS_AUTOINDEX 3 5887 5888 /* 5889 ** CAPI3REF: Custom Page Cache Object 5890 ** 5891 ** The sqlite3_pcache type is opaque. It is implemented by 5892 ** the pluggable module. The SQLite core has no knowledge of 5893 ** its size or internal structure and never deals with the 5894 ** sqlite3_pcache object except by holding and passing pointers 5895 ** to the object. 5896 ** 5897 ** See [sqlite3_pcache_methods] for additional information. 5898 */ 5899 typedef struct sqlite3_pcache sqlite3_pcache; 5900 5901 /* 5902 ** CAPI3REF: Application Defined Page Cache. 5903 ** KEYWORDS: {page cache} 5904 ** 5905 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can 5906 ** register an alternative page cache implementation by passing in an 5907 ** instance of the sqlite3_pcache_methods structure.)^ 5908 ** In many applications, most of the heap memory allocated by 5909 ** SQLite is used for the page cache. 5910 ** By implementing a 5911 ** custom page cache using this API, an application can better control 5912 ** the amount of memory consumed by SQLite, the way in which 5913 ** that memory is allocated and released, and the policies used to 5914 ** determine exactly which parts of a database file are cached and for 5915 ** how long. 5916 ** 5917 ** The alternative page cache mechanism is an 5918 ** extreme measure that is only needed by the most demanding applications. 5919 ** The built-in page cache is recommended for most uses. 5920 ** 5921 ** ^(The contents of the sqlite3_pcache_methods structure are copied to an 5922 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence 5923 ** the application may discard the parameter after the call to 5924 ** [sqlite3_config()] returns.)^ 5925 ** 5926 ** [[the xInit() page cache method]] 5927 ** ^(The xInit() method is called once for each effective 5928 ** call to [sqlite3_initialize()])^ 5929 ** (usually only once during the lifetime of the process). ^(The xInit() 5930 ** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^ 5931 ** The intent of the xInit() method is to set up global data structures 5932 ** required by the custom page cache implementation. 5933 ** ^(If the xInit() method is NULL, then the 5934 ** built-in default page cache is used instead of the application defined 5935 ** page cache.)^ 5936 ** 5937 ** [[the xShutdown() page cache method]] 5938 ** ^The xShutdown() method is called by [sqlite3_shutdown()]. 5939 ** It can be used to clean up 5940 ** any outstanding resources before process shutdown, if required. 5941 ** ^The xShutdown() method may be NULL. 5942 ** 5943 ** ^SQLite automatically serializes calls to the xInit method, 5944 ** so the xInit method need not be threadsafe. ^The 5945 ** xShutdown method is only called from [sqlite3_shutdown()] so it does 5946 ** not need to be threadsafe either. All other methods must be threadsafe 5947 ** in multithreaded applications. 5948 ** 5949 ** ^SQLite will never invoke xInit() more than once without an intervening 5950 ** call to xShutdown(). 5951 ** 5952 ** [[the xCreate() page cache methods]] 5953 ** ^SQLite invokes the xCreate() method to construct a new cache instance. 5954 ** SQLite will typically create one cache instance for each open database file, 5955 ** though this is not guaranteed. ^The 5956 ** first parameter, szPage, is the size in bytes of the pages that must 5957 ** be allocated by the cache. ^szPage will not be a power of two. ^szPage 5958 ** will the page size of the database file that is to be cached plus an 5959 ** increment (here called "R") of less than 250. SQLite will use the 5960 ** extra R bytes on each page to store metadata about the underlying 5961 ** database page on disk. The value of R depends 5962 ** on the SQLite version, the target platform, and how SQLite was compiled. 5963 ** ^(R is constant for a particular build of SQLite. Except, there are two 5964 ** distinct values of R when SQLite is compiled with the proprietary 5965 ** ZIPVFS extension.)^ ^The second argument to 5966 ** xCreate(), bPurgeable, is true if the cache being created will 5967 ** be used to cache database pages of a file stored on disk, or 5968 ** false if it is used for an in-memory database. The cache implementation 5969 ** does not have to do anything special based with the value of bPurgeable; 5970 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 5971 ** never invoke xUnpin() except to deliberately delete a page. 5972 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 5973 ** false will always have the "discard" flag set to true. 5974 ** ^Hence, a cache created with bPurgeable false will 5975 ** never contain any unpinned pages. 5976 ** 5977 ** [[the xCachesize() page cache method]] 5978 ** ^(The xCachesize() method may be called at any time by SQLite to set the 5979 ** suggested maximum cache-size (number of pages stored by) the cache 5980 ** instance passed as the first argument. This is the value configured using 5981 ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 5982 ** parameter, the implementation is not required to do anything with this 5983 ** value; it is advisory only. 5984 ** 5985 ** [[the xPagecount() page cache methods]] 5986 ** The xPagecount() method must return the number of pages currently 5987 ** stored in the cache, both pinned and unpinned. 5988 ** 5989 ** [[the xFetch() page cache methods]] 5990 ** The xFetch() method locates a page in the cache and returns a pointer to 5991 ** the page, or a NULL pointer. 5992 ** A "page", in this context, means a buffer of szPage bytes aligned at an 5993 ** 8-byte boundary. The page to be fetched is determined by the key. ^The 5994 ** minimum key value is 1. After it has been retrieved using xFetch, the page 5995 ** is considered to be "pinned". 5996 ** 5997 ** If the requested page is already in the page cache, then the page cache 5998 ** implementation must return a pointer to the page buffer with its content 5999 ** intact. If the requested page is not already in the cache, then the 6000 ** cache implementation should use the value of the createFlag 6001 ** parameter to help it determined what action to take: 6002 ** 6003 ** <table border=1 width=85% align=center> 6004 ** <tr><th> createFlag <th> Behaviour when page is not already in cache 6005 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6006 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6007 ** Otherwise return NULL. 6008 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6009 ** NULL if allocating a new page is effectively impossible. 6010 ** </table> 6011 ** 6012 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6013 ** will only use a createFlag of 2 after a prior call with a createFlag of 1 6014 ** failed.)^ In between the to xFetch() calls, SQLite may 6015 ** attempt to unpin one or more cache pages by spilling the content of 6016 ** pinned pages to disk and synching the operating system disk cache. 6017 ** 6018 ** [[the xUnpin() page cache method]] 6019 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6020 ** as its second argument. If the third parameter, discard, is non-zero, 6021 ** then the page must be evicted from the cache. 6022 ** ^If the discard parameter is 6023 ** zero, then the page may be discarded or retained at the discretion of 6024 ** page cache implementation. ^The page cache implementation 6025 ** may choose to evict unpinned pages at any time. 6026 ** 6027 ** The cache must not perform any reference counting. A single 6028 ** call to xUnpin() unpins the page regardless of the number of prior calls 6029 ** to xFetch(). 6030 ** 6031 ** [[the xRekey() page cache methods]] 6032 ** The xRekey() method is used to change the key value associated with the 6033 ** page passed as the second argument. If the cache 6034 ** previously contains an entry associated with newKey, it must be 6035 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6036 ** to be pinned. 6037 ** 6038 ** When SQLite calls the xTruncate() method, the cache must discard all 6039 ** existing cache entries with page numbers (keys) greater than or equal 6040 ** to the value of the iLimit parameter passed to xTruncate(). If any 6041 ** of these pages are pinned, they are implicitly unpinned, meaning that 6042 ** they can be safely discarded. 6043 ** 6044 ** [[the xDestroy() page cache method]] 6045 ** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6046 ** All resources associated with the specified cache should be freed. ^After 6047 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6048 ** handle invalid, and will not use it with any other sqlite3_pcache_methods 6049 ** functions. 6050 */ 6051 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 6052 struct sqlite3_pcache_methods { 6053 void *pArg; 6054 int (*xInit)(void*); 6055 void (*xShutdown)(void*); 6056 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 6057 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6058 int (*xPagecount)(sqlite3_pcache*); 6059 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6060 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 6061 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 6062 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6063 void (*xDestroy)(sqlite3_pcache*); 6064 }; 6065 6066 /* 6067 ** CAPI3REF: Online Backup Object 6068 ** 6069 ** The sqlite3_backup object records state information about an ongoing 6070 ** online backup operation. ^The sqlite3_backup object is created by 6071 ** a call to [sqlite3_backup_init()] and is destroyed by a call to 6072 ** [sqlite3_backup_finish()]. 6073 ** 6074 ** See Also: [Using the SQLite Online Backup API] 6075 */ 6076 typedef struct sqlite3_backup sqlite3_backup; 6077 6078 /* 6079 ** CAPI3REF: Online Backup API. 6080 ** 6081 ** The backup API copies the content of one database into another. 6082 ** It is useful either for creating backups of databases or 6083 ** for copying in-memory databases to or from persistent files. 6084 ** 6085 ** See Also: [Using the SQLite Online Backup API] 6086 ** 6087 ** ^SQLite holds a write transaction open on the destination database file 6088 ** for the duration of the backup operation. 6089 ** ^The source database is read-locked only while it is being read; 6090 ** it is not locked continuously for the entire backup operation. 6091 ** ^Thus, the backup may be performed on a live source database without 6092 ** preventing other database connections from 6093 ** reading or writing to the source database while the backup is underway. 6094 ** 6095 ** ^(To perform a backup operation: 6096 ** <ol> 6097 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the 6098 ** backup, 6099 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 6100 ** the data between the two databases, and finally 6101 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources 6102 ** associated with the backup operation. 6103 ** </ol>)^ 6104 ** There should be exactly one call to sqlite3_backup_finish() for each 6105 ** successful call to sqlite3_backup_init(). 6106 ** 6107 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 6108 ** 6109 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 6110 ** [database connection] associated with the destination database 6111 ** and the database name, respectively. 6112 ** ^The database name is "main" for the main database, "temp" for the 6113 ** temporary database, or the name specified after the AS keyword in 6114 ** an [ATTACH] statement for an attached database. 6115 ** ^The S and M arguments passed to 6116 ** sqlite3_backup_init(D,N,S,M) identify the [database connection] 6117 ** and database name of the source database, respectively. 6118 ** ^The source and destination [database connections] (parameters S and D) 6119 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 6120 ** an error. 6121 ** 6122 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 6123 ** returned and an error code and error message are stored in the 6124 ** destination [database connection] D. 6125 ** ^The error code and message for the failed call to sqlite3_backup_init() 6126 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 6127 ** [sqlite3_errmsg16()] functions. 6128 ** ^A successful call to sqlite3_backup_init() returns a pointer to an 6129 ** [sqlite3_backup] object. 6130 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 6131 ** sqlite3_backup_finish() functions to perform the specified backup 6132 ** operation. 6133 ** 6134 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 6135 ** 6136 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 6137 ** the source and destination databases specified by [sqlite3_backup] object B. 6138 ** ^If N is negative, all remaining source pages are copied. 6139 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 6140 ** are still more pages to be copied, then the function returns [SQLITE_OK]. 6141 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 6142 ** from source to destination, then it returns [SQLITE_DONE]. 6143 ** ^If an error occurs while running sqlite3_backup_step(B,N), 6144 ** then an [error code] is returned. ^As well as [SQLITE_OK] and 6145 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 6146 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 6147 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 6148 ** 6149 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 6150 ** <ol> 6151 ** <li> the destination database was opened read-only, or 6152 ** <li> the destination database is using write-ahead-log journaling 6153 ** and the destination and source page sizes differ, or 6154 ** <li> the destination database is an in-memory database and the 6155 ** destination and source page sizes differ. 6156 ** </ol>)^ 6157 ** 6158 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 6159 ** the [sqlite3_busy_handler | busy-handler function] 6160 ** is invoked (if one is specified). ^If the 6161 ** busy-handler returns non-zero before the lock is available, then 6162 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 6163 ** sqlite3_backup_step() can be retried later. ^If the source 6164 ** [database connection] 6165 ** is being used to write to the source database when sqlite3_backup_step() 6166 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 6167 ** case the call to sqlite3_backup_step() can be retried later on. ^(If 6168 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 6169 ** [SQLITE_READONLY] is returned, then 6170 ** there is no point in retrying the call to sqlite3_backup_step(). These 6171 ** errors are considered fatal.)^ The application must accept 6172 ** that the backup operation has failed and pass the backup operation handle 6173 ** to the sqlite3_backup_finish() to release associated resources. 6174 ** 6175 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock 6176 ** on the destination file. ^The exclusive lock is not released until either 6177 ** sqlite3_backup_finish() is called or the backup operation is complete 6178 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 6179 ** sqlite3_backup_step() obtains a [shared lock] on the source database that 6180 ** lasts for the duration of the sqlite3_backup_step() call. 6181 ** ^Because the source database is not locked between calls to 6182 ** sqlite3_backup_step(), the source database may be modified mid-way 6183 ** through the backup process. ^If the source database is modified by an 6184 ** external process or via a database connection other than the one being 6185 ** used by the backup operation, then the backup will be automatically 6186 ** restarted by the next call to sqlite3_backup_step(). ^If the source 6187 ** database is modified by the using the same database connection as is used 6188 ** by the backup operation, then the backup database is automatically 6189 ** updated at the same time. 6190 ** 6191 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 6192 ** 6193 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 6194 ** application wishes to abandon the backup operation, the application 6195 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 6196 ** ^The sqlite3_backup_finish() interfaces releases all 6197 ** resources associated with the [sqlite3_backup] object. 6198 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 6199 ** active write-transaction on the destination database is rolled back. 6200 ** The [sqlite3_backup] object is invalid 6201 ** and may not be used following a call to sqlite3_backup_finish(). 6202 ** 6203 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 6204 ** sqlite3_backup_step() errors occurred, regardless or whether or not 6205 ** sqlite3_backup_step() completed. 6206 ** ^If an out-of-memory condition or IO error occurred during any prior 6207 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 6208 ** sqlite3_backup_finish() returns the corresponding [error code]. 6209 ** 6210 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 6211 ** is not a permanent error and does not affect the return value of 6212 ** sqlite3_backup_finish(). 6213 ** 6214 ** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]] 6215 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 6216 ** 6217 ** ^Each call to sqlite3_backup_step() sets two values inside 6218 ** the [sqlite3_backup] object: the number of pages still to be backed 6219 ** up and the total number of pages in the source database file. 6220 ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 6221 ** retrieve these two values, respectively. 6222 ** 6223 ** ^The values returned by these functions are only updated by 6224 ** sqlite3_backup_step(). ^If the source database is modified during a backup 6225 ** operation, then the values are not updated to account for any extra 6226 ** pages that need to be updated or the size of the source database file 6227 ** changing. 6228 ** 6229 ** <b>Concurrent Usage of Database Handles</b> 6230 ** 6231 ** ^The source [database connection] may be used by the application for other 6232 ** purposes while a backup operation is underway or being initialized. 6233 ** ^If SQLite is compiled and configured to support threadsafe database 6234 ** connections, then the source database connection may be used concurrently 6235 ** from within other threads. 6236 ** 6237 ** However, the application must guarantee that the destination 6238 ** [database connection] is not passed to any other API (by any thread) after 6239 ** sqlite3_backup_init() is called and before the corresponding call to 6240 ** sqlite3_backup_finish(). SQLite does not currently check to see 6241 ** if the application incorrectly accesses the destination [database connection] 6242 ** and so no error code is reported, but the operations may malfunction 6243 ** nevertheless. Use of the destination database connection while a 6244 ** backup is in progress might also also cause a mutex deadlock. 6245 ** 6246 ** If running in [shared cache mode], the application must 6247 ** guarantee that the shared cache used by the destination database 6248 ** is not accessed while the backup is running. In practice this means 6249 ** that the application must guarantee that the disk file being 6250 ** backed up to is not accessed by any connection within the process, 6251 ** not just the specific connection that was passed to sqlite3_backup_init(). 6252 ** 6253 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple 6254 ** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 6255 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 6256 ** APIs are not strictly speaking threadsafe. If they are invoked at the 6257 ** same time as another thread is invoking sqlite3_backup_step() it is 6258 ** possible that they return invalid values. 6259 */ 6260 SQLITE_API sqlite3_backup *sqlite3_backup_init( 6261 sqlite3 *pDest, /* Destination database handle */ 6262 const char *zDestName, /* Destination database name */ 6263 sqlite3 *pSource, /* Source database handle */ 6264 const char *zSourceName /* Source database name */ 6265 ); 6266 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage); 6267 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p); 6268 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p); 6269 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p); 6270 6271 /* 6272 ** CAPI3REF: Unlock Notification 6273 ** 6274 ** ^When running in shared-cache mode, a database operation may fail with 6275 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 6276 ** individual tables within the shared-cache cannot be obtained. See 6277 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 6278 ** ^This API may be used to register a callback that SQLite will invoke 6279 ** when the connection currently holding the required lock relinquishes it. 6280 ** ^This API is only available if the library was compiled with the 6281 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 6282 ** 6283 ** See Also: [Using the SQLite Unlock Notification Feature]. 6284 ** 6285 ** ^Shared-cache locks are released when a database connection concludes 6286 ** its current transaction, either by committing it or rolling it back. 6287 ** 6288 ** ^When a connection (known as the blocked connection) fails to obtain a 6289 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 6290 ** identity of the database connection (the blocking connection) that 6291 ** has locked the required resource is stored internally. ^After an 6292 ** application receives an SQLITE_LOCKED error, it may call the 6293 ** sqlite3_unlock_notify() method with the blocked connection handle as 6294 ** the first argument to register for a callback that will be invoked 6295 ** when the blocking connections current transaction is concluded. ^The 6296 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 6297 ** call that concludes the blocking connections transaction. 6298 ** 6299 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 6300 ** there is a chance that the blocking connection will have already 6301 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 6302 ** If this happens, then the specified callback is invoked immediately, 6303 ** from within the call to sqlite3_unlock_notify().)^ 6304 ** 6305 ** ^If the blocked connection is attempting to obtain a write-lock on a 6306 ** shared-cache table, and more than one other connection currently holds 6307 ** a read-lock on the same table, then SQLite arbitrarily selects one of 6308 ** the other connections to use as the blocking connection. 6309 ** 6310 ** ^(There may be at most one unlock-notify callback registered by a 6311 ** blocked connection. If sqlite3_unlock_notify() is called when the 6312 ** blocked connection already has a registered unlock-notify callback, 6313 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 6314 ** called with a NULL pointer as its second argument, then any existing 6315 ** unlock-notify callback is canceled. ^The blocked connections 6316 ** unlock-notify callback may also be canceled by closing the blocked 6317 ** connection using [sqlite3_close()]. 6318 ** 6319 ** The unlock-notify callback is not reentrant. If an application invokes 6320 ** any sqlite3_xxx API functions from within an unlock-notify callback, a 6321 ** crash or deadlock may be the result. 6322 ** 6323 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 6324 ** returns SQLITE_OK. 6325 ** 6326 ** <b>Callback Invocation Details</b> 6327 ** 6328 ** When an unlock-notify callback is registered, the application provides a 6329 ** single void* pointer that is passed to the callback when it is invoked. 6330 ** However, the signature of the callback function allows SQLite to pass 6331 ** it an array of void* context pointers. The first argument passed to 6332 ** an unlock-notify callback is a pointer to an array of void* pointers, 6333 ** and the second is the number of entries in the array. 6334 ** 6335 ** When a blocking connections transaction is concluded, there may be 6336 ** more than one blocked connection that has registered for an unlock-notify 6337 ** callback. ^If two or more such blocked connections have specified the 6338 ** same callback function, then instead of invoking the callback function 6339 ** multiple times, it is invoked once with the set of void* context pointers 6340 ** specified by the blocked connections bundled together into an array. 6341 ** This gives the application an opportunity to prioritize any actions 6342 ** related to the set of unblocked database connections. 6343 ** 6344 ** <b>Deadlock Detection</b> 6345 ** 6346 ** Assuming that after registering for an unlock-notify callback a 6347 ** database waits for the callback to be issued before taking any further 6348 ** action (a reasonable assumption), then using this API may cause the 6349 ** application to deadlock. For example, if connection X is waiting for 6350 ** connection Y's transaction to be concluded, and similarly connection 6351 ** Y is waiting on connection X's transaction, then neither connection 6352 ** will proceed and the system may remain deadlocked indefinitely. 6353 ** 6354 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 6355 ** detection. ^If a given call to sqlite3_unlock_notify() would put the 6356 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no 6357 ** unlock-notify callback is registered. The system is said to be in 6358 ** a deadlocked state if connection A has registered for an unlock-notify 6359 ** callback on the conclusion of connection B's transaction, and connection 6360 ** B has itself registered for an unlock-notify callback when connection 6361 ** A's transaction is concluded. ^Indirect deadlock is also detected, so 6362 ** the system is also considered to be deadlocked if connection B has 6363 ** registered for an unlock-notify callback on the conclusion of connection 6364 ** C's transaction, where connection C is waiting on connection A. ^Any 6365 ** number of levels of indirection are allowed. 6366 ** 6367 ** <b>The "DROP TABLE" Exception</b> 6368 ** 6369 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 6370 ** always appropriate to call sqlite3_unlock_notify(). There is however, 6371 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 6372 ** SQLite checks if there are any currently executing SELECT statements 6373 ** that belong to the same connection. If there are, SQLITE_LOCKED is 6374 ** returned. In this case there is no "blocking connection", so invoking 6375 ** sqlite3_unlock_notify() results in the unlock-notify callback being 6376 ** invoked immediately. If the application then re-attempts the "DROP TABLE" 6377 ** or "DROP INDEX" query, an infinite loop might be the result. 6378 ** 6379 ** One way around this problem is to check the extended error code returned 6380 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the 6381 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 6382 ** the special "DROP TABLE/INDEX" case, the extended error code is just 6383 ** SQLITE_LOCKED.)^ 6384 */ 6385 SQLITE_API int sqlite3_unlock_notify( 6386 sqlite3 *pBlocked, /* Waiting connection */ 6387 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 6388 void *pNotifyArg /* Argument to pass to xNotify */ 6389 ); 6390 6391 6392 /* 6393 ** CAPI3REF: String Comparison 6394 ** 6395 ** ^The [sqlite3_strnicmp()] API allows applications and extensions to 6396 ** compare the contents of two buffers containing UTF-8 strings in a 6397 ** case-independent fashion, using the same definition of case independence 6398 ** that SQLite uses internally when comparing identifiers. 6399 */ 6400 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int); 6401 6402 /* 6403 ** CAPI3REF: Error Logging Interface 6404 ** 6405 ** ^The [sqlite3_log()] interface writes a message into the error log 6406 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 6407 ** ^If logging is enabled, the zFormat string and subsequent arguments are 6408 ** used with [sqlite3_snprintf()] to generate the final output string. 6409 ** 6410 ** The sqlite3_log() interface is intended for use by extensions such as 6411 ** virtual tables, collating functions, and SQL functions. While there is 6412 ** nothing to prevent an application from calling sqlite3_log(), doing so 6413 ** is considered bad form. 6414 ** 6415 ** The zFormat string must not be NULL. 6416 ** 6417 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine 6418 ** will not use dynamically allocated memory. The log message is stored in 6419 ** a fixed-length buffer on the stack. If the log message is longer than 6420 ** a few hundred characters, it will be truncated to the length of the 6421 ** buffer. 6422 */ 6423 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...); 6424 6425 /* 6426 ** CAPI3REF: Write-Ahead Log Commit Hook 6427 ** 6428 ** ^The [sqlite3_wal_hook()] function is used to register a callback that 6429 ** will be invoked each time a database connection commits data to a 6430 ** [write-ahead log] (i.e. whenever a transaction is committed in 6431 ** [journal_mode | journal_mode=WAL mode]). 6432 ** 6433 ** ^The callback is invoked by SQLite after the commit has taken place and 6434 ** the associated write-lock on the database released, so the implementation 6435 ** may read, write or [checkpoint] the database as required. 6436 ** 6437 ** ^The first parameter passed to the callback function when it is invoked 6438 ** is a copy of the third parameter passed to sqlite3_wal_hook() when 6439 ** registering the callback. ^The second is a copy of the database handle. 6440 ** ^The third parameter is the name of the database that was written to - 6441 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 6442 ** is the number of pages currently in the write-ahead log file, 6443 ** including those that were just committed. 6444 ** 6445 ** The callback function should normally return [SQLITE_OK]. ^If an error 6446 ** code is returned, that error will propagate back up through the 6447 ** SQLite code base to cause the statement that provoked the callback 6448 ** to report an error, though the commit will have still occurred. If the 6449 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 6450 ** that does not correspond to any valid SQLite error code, the results 6451 ** are undefined. 6452 ** 6453 ** A single database handle may have at most a single write-ahead log callback 6454 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 6455 ** previously registered write-ahead log callback. ^Note that the 6456 ** [sqlite3_wal_autocheckpoint()] interface and the 6457 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 6458 ** those overwrite any prior [sqlite3_wal_hook()] settings. 6459 */ 6460 SQLITE_API void *sqlite3_wal_hook( 6461 sqlite3*, 6462 int(*)(void *,sqlite3*,const char*,int), 6463 void* 6464 ); 6465 6466 /* 6467 ** CAPI3REF: Configure an auto-checkpoint 6468 ** 6469 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 6470 ** [sqlite3_wal_hook()] that causes any database on [database connection] D 6471 ** to automatically [checkpoint] 6472 ** after committing a transaction if there are N or 6473 ** more frames in the [write-ahead log] file. ^Passing zero or 6474 ** a negative value as the nFrame parameter disables automatic 6475 ** checkpoints entirely. 6476 ** 6477 ** ^The callback registered by this function replaces any existing callback 6478 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 6479 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 6480 ** configured by this function. 6481 ** 6482 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 6483 ** from SQL. 6484 ** 6485 ** ^Every new [database connection] defaults to having the auto-checkpoint 6486 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 6487 ** pages. The use of this interface 6488 ** is only necessary if the default setting is found to be suboptimal 6489 ** for a particular application. 6490 */ 6491 SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 6492 6493 /* 6494 ** CAPI3REF: Checkpoint a database 6495 ** 6496 ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 6497 ** on [database connection] D to be [checkpointed]. ^If X is NULL or an 6498 ** empty string, then a checkpoint is run on all databases of 6499 ** connection D. ^If the database connection D is not in 6500 ** [WAL | write-ahead log mode] then this interface is a harmless no-op. 6501 ** 6502 ** ^The [wal_checkpoint pragma] can be used to invoke this interface 6503 ** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 6504 ** [wal_autocheckpoint pragma] can be used to cause this interface to be 6505 ** run whenever the WAL reaches a certain size threshold. 6506 ** 6507 ** See also: [sqlite3_wal_checkpoint_v2()] 6508 */ 6509 SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 6510 6511 /* 6512 ** CAPI3REF: Checkpoint a database 6513 ** 6514 ** Run a checkpoint operation on WAL database zDb attached to database 6515 ** handle db. The specific operation is determined by the value of the 6516 ** eMode parameter: 6517 ** 6518 ** <dl> 6519 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 6520 ** Checkpoint as many frames as possible without waiting for any database 6521 ** readers or writers to finish. Sync the db file if all frames in the log 6522 ** are checkpointed. This mode is the same as calling 6523 ** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked. 6524 ** 6525 ** <dt>SQLITE_CHECKPOINT_FULL<dd> 6526 ** This mode blocks (calls the busy-handler callback) until there is no 6527 ** database writer and all readers are reading from the most recent database 6528 ** snapshot. It then checkpoints all frames in the log file and syncs the 6529 ** database file. This call blocks database writers while it is running, 6530 ** but not database readers. 6531 ** 6532 ** <dt>SQLITE_CHECKPOINT_RESTART<dd> 6533 ** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after 6534 ** checkpointing the log file it blocks (calls the busy-handler callback) 6535 ** until all readers are reading from the database file only. This ensures 6536 ** that the next client to write to the database file restarts the log file 6537 ** from the beginning. This call blocks database writers while it is running, 6538 ** but not database readers. 6539 ** </dl> 6540 ** 6541 ** If pnLog is not NULL, then *pnLog is set to the total number of frames in 6542 ** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to 6543 ** the total number of checkpointed frames (including any that were already 6544 ** checkpointed when this function is called). *pnLog and *pnCkpt may be 6545 ** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK. 6546 ** If no values are available because of an error, they are both set to -1 6547 ** before returning to communicate this to the caller. 6548 ** 6549 ** All calls obtain an exclusive "checkpoint" lock on the database file. If 6550 ** any other process is running a checkpoint operation at the same time, the 6551 ** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a 6552 ** busy-handler configured, it will not be invoked in this case. 6553 ** 6554 ** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive 6555 ** "writer" lock on the database file. If the writer lock cannot be obtained 6556 ** immediately, and a busy-handler is configured, it is invoked and the writer 6557 ** lock retried until either the busy-handler returns 0 or the lock is 6558 ** successfully obtained. The busy-handler is also invoked while waiting for 6559 ** database readers as described above. If the busy-handler returns 0 before 6560 ** the writer lock is obtained or while waiting for database readers, the 6561 ** checkpoint operation proceeds from that point in the same way as 6562 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 6563 ** without blocking any further. SQLITE_BUSY is returned in this case. 6564 ** 6565 ** If parameter zDb is NULL or points to a zero length string, then the 6566 ** specified operation is attempted on all WAL databases. In this case the 6567 ** values written to output parameters *pnLog and *pnCkpt are undefined. If 6568 ** an SQLITE_BUSY error is encountered when processing one or more of the 6569 ** attached WAL databases, the operation is still attempted on any remaining 6570 ** attached databases and SQLITE_BUSY is returned to the caller. If any other 6571 ** error occurs while processing an attached database, processing is abandoned 6572 ** and the error code returned to the caller immediately. If no error 6573 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached 6574 ** databases, SQLITE_OK is returned. 6575 ** 6576 ** If database zDb is the name of an attached database that is not in WAL 6577 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If 6578 ** zDb is not NULL (or a zero length string) and is not the name of any 6579 ** attached database, SQLITE_ERROR is returned to the caller. 6580 */ 6581 SQLITE_API int sqlite3_wal_checkpoint_v2( 6582 sqlite3 *db, /* Database handle */ 6583 const char *zDb, /* Name of attached database (or NULL) */ 6584 int eMode, /* SQLITE_CHECKPOINT_* value */ 6585 int *pnLog, /* OUT: Size of WAL log in frames */ 6586 int *pnCkpt /* OUT: Total number of frames checkpointed */ 6587 ); 6588 6589 /* 6590 ** CAPI3REF: Checkpoint operation parameters 6591 ** 6592 ** These constants can be used as the 3rd parameter to 6593 ** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()] 6594 ** documentation for additional information about the meaning and use of 6595 ** each of these values. 6596 */ 6597 #define SQLITE_CHECKPOINT_PASSIVE 0 6598 #define SQLITE_CHECKPOINT_FULL 1 6599 #define SQLITE_CHECKPOINT_RESTART 2 6600 6601 /* 6602 ** CAPI3REF: Virtual Table Interface Configuration 6603 ** 6604 ** This function may be called by either the [xConnect] or [xCreate] method 6605 ** of a [virtual table] implementation to configure 6606 ** various facets of the virtual table interface. 6607 ** 6608 ** If this interface is invoked outside the context of an xConnect or 6609 ** xCreate virtual table method then the behavior is undefined. 6610 ** 6611 ** At present, there is only one option that may be configured using 6612 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 6613 ** may be added in the future. 6614 */ 6615 SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...); 6616 6617 /* 6618 ** CAPI3REF: Virtual Table Configuration Options 6619 ** 6620 ** These macros define the various options to the 6621 ** [sqlite3_vtab_config()] interface that [virtual table] implementations 6622 ** can use to customize and optimize their behavior. 6623 ** 6624 ** <dl> 6625 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 6626 ** <dd>Calls of the form 6627 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 6628 ** where X is an integer. If X is zero, then the [virtual table] whose 6629 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 6630 ** support constraints. In this configuration (which is the default) if 6631 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 6632 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 6633 ** specified as part of the users SQL statement, regardless of the actual 6634 ** ON CONFLICT mode specified. 6635 ** 6636 ** If X is non-zero, then the virtual table implementation guarantees 6637 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 6638 ** any modifications to internal or persistent data structures have been made. 6639 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 6640 ** is able to roll back a statement or database transaction, and abandon 6641 ** or continue processing the current SQL statement as appropriate. 6642 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 6643 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 6644 ** had been ABORT. 6645 ** 6646 ** Virtual table implementations that are required to handle OR REPLACE 6647 ** must do so within the [xUpdate] method. If a call to the 6648 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON 6649 ** CONFLICT policy is REPLACE, the virtual table implementation should 6650 ** silently replace the appropriate rows within the xUpdate callback and 6651 ** return SQLITE_OK. Or, if this is not possible, it may return 6652 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 6653 ** constraint handling. 6654 ** </dl> 6655 */ 6656 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 6657 6658 /* 6659 ** CAPI3REF: Determine The Virtual Table Conflict Policy 6660 ** 6661 ** This function may only be called from within a call to the [xUpdate] method 6662 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 6663 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 6664 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 6665 ** of the SQL statement that triggered the call to the [xUpdate] method of the 6666 ** [virtual table]. 6667 */ 6668 SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *); 6669 6670 /* 6671 ** CAPI3REF: Conflict resolution modes 6672 ** 6673 ** These constants are returned by [sqlite3_vtab_on_conflict()] to 6674 ** inform a [virtual table] implementation what the [ON CONFLICT] mode 6675 ** is for the SQL statement being evaluated. 6676 ** 6677 ** Note that the [SQLITE_IGNORE] constant is also used as a potential 6678 ** return value from the [sqlite3_set_authorizer()] callback and that 6679 ** [SQLITE_ABORT] is also a [result code]. 6680 */ 6681 #define SQLITE_ROLLBACK 1 6682 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 6683 #define SQLITE_FAIL 3 6684 /* #define SQLITE_ABORT 4 // Also an error code */ 6685 #define SQLITE_REPLACE 5 6686 6687 6688 6689 /* 6690 ** Undo the hack that converts floating point types to integer for 6691 ** builds on processors without floating point support. 6692 */ 6693 #ifdef SQLITE_OMIT_FLOATING_POINT 6694 # undef double 6695 #endif 6696 6697 #ifdef __cplusplus 6698 } /* End of the 'extern "C"' block */ 6699 #endif 6700 #endif 6701 6702 /* 6703 ** 2010 August 30 6704 ** 6705 ** The author disclaims copyright to this source code. In place of 6706 ** a legal notice, here is a blessing: 6707 ** 6708 ** May you do good and not evil. 6709 ** May you find forgiveness for yourself and forgive others. 6710 ** May you share freely, never taking more than you give. 6711 ** 6712 ************************************************************************* 6713 */ 6714 6715 #ifndef _SQLITE3RTREE_H_ 6716 #define _SQLITE3RTREE_H_ 6717 6718 6719 #ifdef __cplusplus 6720 extern "C" { 6721 #endif 6722 6723 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry; 6724 6725 /* 6726 ** Register a geometry callback named zGeom that can be used as part of an 6727 ** R-Tree geometry query as follows: 6728 ** 6729 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...) 6730 */ 6731 SQLITE_API int sqlite3_rtree_geometry_callback( 6732 sqlite3 *db, 6733 const char *zGeom, 6734 int (*xGeom)(sqlite3_rtree_geometry *, int nCoord, double *aCoord, int *pRes), 6735 void *pContext 6736 ); 6737 6738 6739 /* 6740 ** A pointer to a structure of the following type is passed as the first 6741 ** argument to callbacks registered using rtree_geometry_callback(). 6742 */ 6743 struct sqlite3_rtree_geometry { 6744 void *pContext; /* Copy of pContext passed to s_r_g_c() */ 6745 int nParam; /* Size of array aParam[] */ 6746 double *aParam; /* Parameters passed to SQL geom function */ 6747 void *pUser; /* Callback implementation user data */ 6748 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */ 6749 }; 6750 6751 6752 #ifdef __cplusplus 6753 } /* end of the 'extern "C"' block */ 6754 #endif 6755 6756 #endif /* ifndef _SQLITE3RTREE_H_ */ 6757