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 "3.7.11" 111 #define SQLITE_VERSION_NUMBER 3007011 112 #define SQLITE_SOURCE_ID "2012-03-20 11:35:50 00bb9c9ce4f465e6ac321ced2a9d0062dc364669" 113 114 /* 115 ** CAPI3REF: Run-Time Library Version Numbers 116 ** KEYWORDS: sqlite3_version, sqlite3_sourceid 117 ** 118 ** These interfaces provide the same information as the [SQLITE_VERSION], 119 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 120 ** but are associated with the library instead of the header file. ^(Cautious 121 ** programmers might include assert() statements in their application to 122 ** verify that values returned by these interfaces match the macros in 123 ** the header, and thus insure that the application is 124 ** compiled with matching library and header files. 125 ** 126 ** <blockquote><pre> 127 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 128 ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 129 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 130 ** </pre></blockquote>)^ 131 ** 132 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 133 ** macro. ^The sqlite3_libversion() function returns a pointer to the 134 ** to the sqlite3_version[] string constant. The sqlite3_libversion() 135 ** function is provided for use in DLLs since DLL users usually do not have 136 ** direct access to string constants within the DLL. ^The 137 ** sqlite3_libversion_number() function returns an integer equal to 138 ** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 139 ** a pointer to a string constant whose value is the same as the 140 ** [SQLITE_SOURCE_ID] C preprocessor macro. 141 ** 142 ** See also: [sqlite_version()] and [sqlite_source_id()]. 143 */ 144 SQLITE_API SQLITE_EXTERN const char sqlite3_version[]; 145 SQLITE_API const char *sqlite3_libversion(void); 146 SQLITE_API const char *sqlite3_sourceid(void); 147 SQLITE_API int sqlite3_libversion_number(void); 148 149 /* 150 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics 151 ** 152 ** ^The sqlite3_compileoption_used() function returns 0 or 1 153 ** indicating whether the specified option was defined at 154 ** compile time. ^The SQLITE_ prefix may be omitted from the 155 ** option name passed to sqlite3_compileoption_used(). 156 ** 157 ** ^The sqlite3_compileoption_get() function allows iterating 158 ** over the list of options that were defined at compile time by 159 ** returning the N-th compile time option string. ^If N is out of range, 160 ** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 161 ** prefix is omitted from any strings returned by 162 ** sqlite3_compileoption_get(). 163 ** 164 ** ^Support for the diagnostic functions sqlite3_compileoption_used() 165 ** and sqlite3_compileoption_get() may be omitted by specifying the 166 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 167 ** 168 ** See also: SQL functions [sqlite_compileoption_used()] and 169 ** [sqlite_compileoption_get()] and the [compile_options pragma]. 170 */ 171 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 172 SQLITE_API int sqlite3_compileoption_used(const char *zOptName); 173 SQLITE_API const char *sqlite3_compileoption_get(int N); 174 #endif 175 176 /* 177 ** CAPI3REF: Test To See If The Library Is Threadsafe 178 ** 179 ** ^The sqlite3_threadsafe() function returns zero if and only if 180 ** SQLite was compiled with mutexing code omitted due to the 181 ** [SQLITE_THREADSAFE] compile-time option being set to 0. 182 ** 183 ** SQLite can be compiled with or without mutexes. When 184 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 185 ** are enabled and SQLite is threadsafe. When the 186 ** [SQLITE_THREADSAFE] macro is 0, 187 ** the mutexes are omitted. Without the mutexes, it is not safe 188 ** to use SQLite concurrently from more than one thread. 189 ** 190 ** Enabling mutexes incurs a measurable performance penalty. 191 ** So if speed is of utmost importance, it makes sense to disable 192 ** the mutexes. But for maximum safety, mutexes should be enabled. 193 ** ^The default behavior is for mutexes to be enabled. 194 ** 195 ** This interface can be used by an application to make sure that the 196 ** version of SQLite that it is linking against was compiled with 197 ** the desired setting of the [SQLITE_THREADSAFE] macro. 198 ** 199 ** This interface only reports on the compile-time mutex setting 200 ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 201 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 202 ** can be fully or partially disabled using a call to [sqlite3_config()] 203 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 204 ** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the 205 ** sqlite3_threadsafe() function shows only the compile-time setting of 206 ** thread safety, not any run-time changes to that setting made by 207 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 208 ** is unchanged by calls to sqlite3_config().)^ 209 ** 210 ** See the [threading mode] documentation for additional information. 211 */ 212 SQLITE_API int sqlite3_threadsafe(void); 213 214 /* 215 ** CAPI3REF: Database Connection Handle 216 ** KEYWORDS: {database connection} {database connections} 217 ** 218 ** Each open SQLite database is represented by a pointer to an instance of 219 ** the opaque structure named "sqlite3". It is useful to think of an sqlite3 220 ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 221 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 222 ** 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 indicate 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 #define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 465 466 /* 467 ** CAPI3REF: Flags For File Open Operations 468 ** 469 ** These bit values are intended for use in the 470 ** 3rd parameter to the [sqlite3_open_v2()] interface and 471 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 472 */ 473 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 474 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 475 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 476 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 477 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 478 #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 479 #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 480 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 481 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 482 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 483 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 484 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 485 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 486 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 487 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 488 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 489 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 490 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 491 #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 492 493 /* Reserved: 0x00F00000 */ 494 495 /* 496 ** CAPI3REF: Device Characteristics 497 ** 498 ** The xDeviceCharacteristics method of the [sqlite3_io_methods] 499 ** object returns an integer which is a vector of the these 500 ** bit values expressing I/O characteristics of the mass storage 501 ** device that holds the file that the [sqlite3_io_methods] 502 ** refers to. 503 ** 504 ** The SQLITE_IOCAP_ATOMIC property means that all writes of 505 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 506 ** mean that writes of blocks that are nnn bytes in size and 507 ** are aligned to an address which is an integer multiple of 508 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 509 ** that when data is appended to a file, the data is appended 510 ** first then the size of the file is extended, never the other 511 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 512 ** information is written to disk in the same order as calls 513 ** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 514 ** after reboot following a crash or power loss, the only bytes in a 515 ** file that were written at the application level might have changed 516 ** and that adjacent bytes, even bytes within the same sector are 517 ** guaranteed to be unchanged. 518 */ 519 #define SQLITE_IOCAP_ATOMIC 0x00000001 520 #define SQLITE_IOCAP_ATOMIC512 0x00000002 521 #define SQLITE_IOCAP_ATOMIC1K 0x00000004 522 #define SQLITE_IOCAP_ATOMIC2K 0x00000008 523 #define SQLITE_IOCAP_ATOMIC4K 0x00000010 524 #define SQLITE_IOCAP_ATOMIC8K 0x00000020 525 #define SQLITE_IOCAP_ATOMIC16K 0x00000040 526 #define SQLITE_IOCAP_ATOMIC32K 0x00000080 527 #define SQLITE_IOCAP_ATOMIC64K 0x00000100 528 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200 529 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400 530 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 531 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 532 533 /* 534 ** CAPI3REF: File Locking Levels 535 ** 536 ** SQLite uses one of these integer values as the second 537 ** argument to calls it makes to the xLock() and xUnlock() methods 538 ** of an [sqlite3_io_methods] object. 539 */ 540 #define SQLITE_LOCK_NONE 0 541 #define SQLITE_LOCK_SHARED 1 542 #define SQLITE_LOCK_RESERVED 2 543 #define SQLITE_LOCK_PENDING 3 544 #define SQLITE_LOCK_EXCLUSIVE 4 545 546 /* 547 ** CAPI3REF: Synchronization Type Flags 548 ** 549 ** When SQLite invokes the xSync() method of an 550 ** [sqlite3_io_methods] object it uses a combination of 551 ** these integer values as the second argument. 552 ** 553 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 554 ** sync operation only needs to flush data to mass storage. Inode 555 ** information need not be flushed. If the lower four bits of the flag 556 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 557 ** If the lower four bits equal SQLITE_SYNC_FULL, that means 558 ** to use Mac OS X style fullsync instead of fsync(). 559 ** 560 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 561 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 562 ** settings. The [synchronous pragma] determines when calls to the 563 ** xSync VFS method occur and applies uniformly across all platforms. 564 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 565 ** energetic or rigorous or forceful the sync operations are and 566 ** only make a difference on Mac OSX for the default SQLite code. 567 ** (Third-party VFS implementations might also make the distinction 568 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 569 ** operating systems natively supported by SQLite, only Mac OSX 570 ** cares about the difference.) 571 */ 572 #define SQLITE_SYNC_NORMAL 0x00002 573 #define SQLITE_SYNC_FULL 0x00003 574 #define SQLITE_SYNC_DATAONLY 0x00010 575 576 /* 577 ** CAPI3REF: OS Interface Open File Handle 578 ** 579 ** An [sqlite3_file] object represents an open file in the 580 ** [sqlite3_vfs | OS interface layer]. Individual OS interface 581 ** implementations will 582 ** want to subclass this object by appending additional fields 583 ** for their own use. The pMethods entry is a pointer to an 584 ** [sqlite3_io_methods] object that defines methods for performing 585 ** I/O operations on the open file. 586 */ 587 typedef struct sqlite3_file sqlite3_file; 588 struct sqlite3_file { 589 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 590 }; 591 592 /* 593 ** CAPI3REF: OS Interface File Virtual Methods Object 594 ** 595 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an 596 ** [sqlite3_file] object (or, more commonly, a subclass of the 597 ** [sqlite3_file] object) with a pointer to an instance of this object. 598 ** This object defines the methods used to perform various operations 599 ** against the open file represented by the [sqlite3_file] object. 600 ** 601 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 602 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 603 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 604 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 605 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 606 ** to NULL. 607 ** 608 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 609 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 610 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 611 ** flag may be ORed in to indicate that only the data of the file 612 ** and not its inode needs to be synced. 613 ** 614 ** The integer values to xLock() and xUnlock() are one of 615 ** <ul> 616 ** <li> [SQLITE_LOCK_NONE], 617 ** <li> [SQLITE_LOCK_SHARED], 618 ** <li> [SQLITE_LOCK_RESERVED], 619 ** <li> [SQLITE_LOCK_PENDING], or 620 ** <li> [SQLITE_LOCK_EXCLUSIVE]. 621 ** </ul> 622 ** xLock() increases the lock. xUnlock() decreases the lock. 623 ** The xCheckReservedLock() method checks whether any database connection, 624 ** either in this process or in some other process, is holding a RESERVED, 625 ** PENDING, or EXCLUSIVE lock on the file. It returns true 626 ** if such a lock exists and false otherwise. 627 ** 628 ** The xFileControl() method is a generic interface that allows custom 629 ** VFS implementations to directly control an open file using the 630 ** [sqlite3_file_control()] interface. The second "op" argument is an 631 ** integer opcode. The third argument is a generic pointer intended to 632 ** point to a structure that may contain arguments or space in which to 633 ** write return values. Potential uses for xFileControl() might be 634 ** functions to enable blocking locks with timeouts, to change the 635 ** locking strategy (for example to use dot-file locks), to inquire 636 ** about the status of a lock, or to break stale locks. The SQLite 637 ** core reserves all opcodes less than 100 for its own use. 638 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 639 ** Applications that define a custom xFileControl method should use opcodes 640 ** greater than 100 to avoid conflicts. VFS implementations should 641 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not 642 ** recognize. 643 ** 644 ** The xSectorSize() method returns the sector size of the 645 ** device that underlies the file. The sector size is the 646 ** minimum write that can be performed without disturbing 647 ** other bytes in the file. The xDeviceCharacteristics() 648 ** method returns a bit vector describing behaviors of the 649 ** underlying device: 650 ** 651 ** <ul> 652 ** <li> [SQLITE_IOCAP_ATOMIC] 653 ** <li> [SQLITE_IOCAP_ATOMIC512] 654 ** <li> [SQLITE_IOCAP_ATOMIC1K] 655 ** <li> [SQLITE_IOCAP_ATOMIC2K] 656 ** <li> [SQLITE_IOCAP_ATOMIC4K] 657 ** <li> [SQLITE_IOCAP_ATOMIC8K] 658 ** <li> [SQLITE_IOCAP_ATOMIC16K] 659 ** <li> [SQLITE_IOCAP_ATOMIC32K] 660 ** <li> [SQLITE_IOCAP_ATOMIC64K] 661 ** <li> [SQLITE_IOCAP_SAFE_APPEND] 662 ** <li> [SQLITE_IOCAP_SEQUENTIAL] 663 ** </ul> 664 ** 665 ** The SQLITE_IOCAP_ATOMIC property means that all writes of 666 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 667 ** mean that writes of blocks that are nnn bytes in size and 668 ** are aligned to an address which is an integer multiple of 669 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 670 ** that when data is appended to a file, the data is appended 671 ** first then the size of the file is extended, never the other 672 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 673 ** information is written to disk in the same order as calls 674 ** to xWrite(). 675 ** 676 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 677 ** in the unread portions of the buffer with zeros. A VFS that 678 ** fails to zero-fill short reads might seem to work. However, 679 ** failure to zero-fill short reads will eventually lead to 680 ** database corruption. 681 */ 682 typedef struct sqlite3_io_methods sqlite3_io_methods; 683 struct sqlite3_io_methods { 684 int iVersion; 685 int (*xClose)(sqlite3_file*); 686 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 687 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 688 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 689 int (*xSync)(sqlite3_file*, int flags); 690 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 691 int (*xLock)(sqlite3_file*, int); 692 int (*xUnlock)(sqlite3_file*, int); 693 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 694 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 695 int (*xSectorSize)(sqlite3_file*); 696 int (*xDeviceCharacteristics)(sqlite3_file*); 697 /* Methods above are valid for version 1 */ 698 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 699 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 700 void (*xShmBarrier)(sqlite3_file*); 701 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 702 /* Methods above are valid for version 2 */ 703 /* Additional methods may be added in future releases */ 704 }; 705 706 /* 707 ** CAPI3REF: Standard File Control Opcodes 708 ** 709 ** These integer constants are opcodes for the xFileControl method 710 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 711 ** interface. 712 ** 713 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 714 ** opcode causes the xFileControl method to write the current state of 715 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 716 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 717 ** into an integer that the pArg argument points to. This capability 718 ** is used during testing and only needs to be supported when SQLITE_TEST 719 ** is defined. 720 ** <ul> 721 ** <li>[[SQLITE_FCNTL_SIZE_HINT]] 722 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 723 ** layer a hint of how large the database file will grow to be during the 724 ** current transaction. This hint is not guaranteed to be accurate but it 725 ** is often close. The underlying VFS might choose to preallocate database 726 ** file space based on this hint in order to help writes to the database 727 ** file run faster. 728 ** 729 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 730 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 731 ** extends and truncates the database file in chunks of a size specified 732 ** by the user. The fourth argument to [sqlite3_file_control()] should 733 ** point to an integer (type int) containing the new chunk-size to use 734 ** for the nominated database. Allocating database file space in large 735 ** chunks (say 1MB at a time), may reduce file-system fragmentation and 736 ** improve performance on some systems. 737 ** 738 ** <li>[[SQLITE_FCNTL_FILE_POINTER]] 739 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 740 ** to the [sqlite3_file] object associated with a particular database 741 ** connection. See the [sqlite3_file_control()] documentation for 742 ** additional information. 743 ** 744 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 745 ** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by 746 ** SQLite and sent to all VFSes in place of a call to the xSync method 747 ** when the database connection has [PRAGMA synchronous] set to OFF.)^ 748 ** Some specialized VFSes need this signal in order to operate correctly 749 ** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most 750 ** VFSes do not need this signal and should silently ignore this opcode. 751 ** Applications should not call [sqlite3_file_control()] with this 752 ** opcode as doing so may disrupt the operation of the specialized VFSes 753 ** that do require it. 754 ** 755 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 756 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 757 ** retry counts and intervals for certain disk I/O operations for the 758 ** windows [VFS] in order to provide robustness in the presence of 759 ** anti-virus programs. By default, the windows VFS will retry file read, 760 ** file write, and file delete operations up to 10 times, with a delay 761 ** of 25 milliseconds before the first retry and with the delay increasing 762 ** by an additional 25 milliseconds with each subsequent retry. This 763 ** opcode allows these two values (10 retries and 25 milliseconds of delay) 764 ** to be adjusted. The values are changed for all database connections 765 ** within the same process. The argument is a pointer to an array of two 766 ** integers where the first integer i the new retry count and the second 767 ** integer is the delay. If either integer is negative, then the setting 768 ** is not changed but instead the prior value of that setting is written 769 ** into the array entry, allowing the current retry settings to be 770 ** interrogated. The zDbName parameter is ignored. 771 ** 772 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 773 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 774 ** persistent [WAL | Write AHead Log] setting. By default, the auxiliary 775 ** write ahead log and shared memory files used for transaction control 776 ** are automatically deleted when the latest connection to the database 777 ** closes. Setting persistent WAL mode causes those files to persist after 778 ** close. Persisting the files is useful when other processes that do not 779 ** have write permission on the directory containing the database file want 780 ** to read the database file, as the WAL and shared memory files must exist 781 ** in order for the database to be readable. The fourth parameter to 782 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 783 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 784 ** WAL mode. If the integer is -1, then it is overwritten with the current 785 ** WAL persistence setting. 786 ** 787 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 788 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 789 ** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 790 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 791 ** xDeviceCharacteristics methods. The fourth parameter to 792 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 793 ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 794 ** mode. If the integer is -1, then it is overwritten with the current 795 ** zero-damage mode setting. 796 ** 797 ** <li>[[SQLITE_FCNTL_OVERWRITE]] 798 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 799 ** a write transaction to indicate that, unless it is rolled back for some 800 ** reason, the entire database file will be overwritten by the current 801 ** transaction. This is used by VACUUM operations. 802 ** 803 ** <li>[[SQLITE_FCNTL_VFSNAME]] 804 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 805 ** all [VFSes] in the VFS stack. The names are of all VFS shims and the 806 ** final bottom-level VFS are written into memory obtained from 807 ** [sqlite3_malloc()] and the result is stored in the char* variable 808 ** that the fourth parameter of [sqlite3_file_control()] points to. 809 ** The caller is responsible for freeing the memory when done. As with 810 ** all file-control actions, there is no guarantee that this will actually 811 ** do anything. Callers should initialize the char* variable to a NULL 812 ** pointer in case this file-control is not implemented. This file-control 813 ** is intended for diagnostic use only. 814 ** 815 ** <li>[[SQLITE_FCNTL_PRAGMA]] 816 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 817 ** file control is sent to the open [sqlite3_file] object corresponding 818 ** to the database file to which the pragma statement refers. ^The argument 819 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 820 ** pointers to strings (char**) in which the second element of the array 821 ** is the name of the pragma and the third element is the argument to the 822 ** pragma or NULL if the pragma has no argument. ^The handler for an 823 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 824 ** of the char** argument point to a string obtained from [sqlite3_mprintf()] 825 ** or the equivalent and that string will become the result of the pragma or 826 ** the error message if the pragma fails. ^If the 827 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 828 ** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 829 ** file control returns [SQLITE_OK], then the parser assumes that the 830 ** VFS has handled the PRAGMA itself and the parser generates a no-op 831 ** prepared statement. ^If the [SQLITE_FCNTL_PRAGMA] file control returns 832 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 833 ** that the VFS encountered an error while handling the [PRAGMA] and the 834 ** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 835 ** file control occurs at the beginning of pragma statement analysis and so 836 ** it is able to override built-in [PRAGMA] statements. 837 ** </ul> 838 */ 839 #define SQLITE_FCNTL_LOCKSTATE 1 840 #define SQLITE_GET_LOCKPROXYFILE 2 841 #define SQLITE_SET_LOCKPROXYFILE 3 842 #define SQLITE_LAST_ERRNO 4 843 #define SQLITE_FCNTL_SIZE_HINT 5 844 #define SQLITE_FCNTL_CHUNK_SIZE 6 845 #define SQLITE_FCNTL_FILE_POINTER 7 846 #define SQLITE_FCNTL_SYNC_OMITTED 8 847 #define SQLITE_FCNTL_WIN32_AV_RETRY 9 848 #define SQLITE_FCNTL_PERSIST_WAL 10 849 #define SQLITE_FCNTL_OVERWRITE 11 850 #define SQLITE_FCNTL_VFSNAME 12 851 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 852 #define SQLITE_FCNTL_PRAGMA 14 853 854 /* 855 ** CAPI3REF: Mutex Handle 856 ** 857 ** The mutex module within SQLite defines [sqlite3_mutex] to be an 858 ** abstract type for a mutex object. The SQLite core never looks 859 ** at the internal representation of an [sqlite3_mutex]. It only 860 ** deals with pointers to the [sqlite3_mutex] object. 861 ** 862 ** Mutexes are created using [sqlite3_mutex_alloc()]. 863 */ 864 typedef struct sqlite3_mutex sqlite3_mutex; 865 866 /* 867 ** CAPI3REF: OS Interface Object 868 ** 869 ** An instance of the sqlite3_vfs object defines the interface between 870 ** the SQLite core and the underlying operating system. The "vfs" 871 ** in the name of the object stands for "virtual file system". See 872 ** the [VFS | VFS documentation] for further information. 873 ** 874 ** The value of the iVersion field is initially 1 but may be larger in 875 ** future versions of SQLite. Additional fields may be appended to this 876 ** object when the iVersion value is increased. Note that the structure 877 ** of the sqlite3_vfs object changes in the transaction between 878 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 879 ** modified. 880 ** 881 ** The szOsFile field is the size of the subclassed [sqlite3_file] 882 ** structure used by this VFS. mxPathname is the maximum length of 883 ** a pathname in this VFS. 884 ** 885 ** Registered sqlite3_vfs objects are kept on a linked list formed by 886 ** the pNext pointer. The [sqlite3_vfs_register()] 887 ** and [sqlite3_vfs_unregister()] interfaces manage this list 888 ** in a thread-safe way. The [sqlite3_vfs_find()] interface 889 ** searches the list. Neither the application code nor the VFS 890 ** implementation should use the pNext pointer. 891 ** 892 ** The pNext field is the only field in the sqlite3_vfs 893 ** structure that SQLite will ever modify. SQLite will only access 894 ** or modify this field while holding a particular static mutex. 895 ** The application should never modify anything within the sqlite3_vfs 896 ** object once the object has been registered. 897 ** 898 ** The zName field holds the name of the VFS module. The name must 899 ** be unique across all VFS modules. 900 ** 901 ** [[sqlite3_vfs.xOpen]] 902 ** ^SQLite guarantees that the zFilename parameter to xOpen 903 ** is either a NULL pointer or string obtained 904 ** from xFullPathname() with an optional suffix added. 905 ** ^If a suffix is added to the zFilename parameter, it will 906 ** consist of a single "-" character followed by no more than 907 ** 11 alphanumeric and/or "-" characters. 908 ** ^SQLite further guarantees that 909 ** the string will be valid and unchanged until xClose() is 910 ** called. Because of the previous sentence, 911 ** the [sqlite3_file] can safely store a pointer to the 912 ** filename if it needs to remember the filename for some reason. 913 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen 914 ** must invent its own temporary name for the file. ^Whenever the 915 ** xFilename parameter is NULL it will also be the case that the 916 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 917 ** 918 ** The flags argument to xOpen() includes all bits set in 919 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 920 ** or [sqlite3_open16()] is used, then flags includes at least 921 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 922 ** If xOpen() opens a file read-only then it sets *pOutFlags to 923 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 924 ** 925 ** ^(SQLite will also add one of the following flags to the xOpen() 926 ** call, depending on the object being opened: 927 ** 928 ** <ul> 929 ** <li> [SQLITE_OPEN_MAIN_DB] 930 ** <li> [SQLITE_OPEN_MAIN_JOURNAL] 931 ** <li> [SQLITE_OPEN_TEMP_DB] 932 ** <li> [SQLITE_OPEN_TEMP_JOURNAL] 933 ** <li> [SQLITE_OPEN_TRANSIENT_DB] 934 ** <li> [SQLITE_OPEN_SUBJOURNAL] 935 ** <li> [SQLITE_OPEN_MASTER_JOURNAL] 936 ** <li> [SQLITE_OPEN_WAL] 937 ** </ul>)^ 938 ** 939 ** The file I/O implementation can use the object type flags to 940 ** change the way it deals with files. For example, an application 941 ** that does not care about crash recovery or rollback might make 942 ** the open of a journal file a no-op. Writes to this journal would 943 ** also be no-ops, and any attempt to read the journal would return 944 ** SQLITE_IOERR. Or the implementation might recognize that a database 945 ** file will be doing page-aligned sector reads and writes in a random 946 ** order and set up its I/O subsystem accordingly. 947 ** 948 ** SQLite might also add one of the following flags to the xOpen method: 949 ** 950 ** <ul> 951 ** <li> [SQLITE_OPEN_DELETEONCLOSE] 952 ** <li> [SQLITE_OPEN_EXCLUSIVE] 953 ** </ul> 954 ** 955 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 956 ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 957 ** will be set for TEMP databases and their journals, transient 958 ** databases, and subjournals. 959 ** 960 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 961 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly 962 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 963 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 964 ** SQLITE_OPEN_CREATE, is used to indicate that file should always 965 ** be created, and that it is an error if it already exists. 966 ** It is <i>not</i> used to indicate the file should be opened 967 ** for exclusive access. 968 ** 969 ** ^At least szOsFile bytes of memory are allocated by SQLite 970 ** to hold the [sqlite3_file] structure passed as the third 971 ** argument to xOpen. The xOpen method does not have to 972 ** allocate the structure; it should just fill it in. Note that 973 ** the xOpen method must set the sqlite3_file.pMethods to either 974 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 975 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 976 ** element will be valid after xOpen returns regardless of the success 977 ** or failure of the xOpen call. 978 ** 979 ** [[sqlite3_vfs.xAccess]] 980 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 981 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 982 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 983 ** to test whether a file is at least readable. The file can be a 984 ** directory. 985 ** 986 ** ^SQLite will always allocate at least mxPathname+1 bytes for the 987 ** output buffer xFullPathname. The exact size of the output buffer 988 ** is also passed as a parameter to both methods. If the output buffer 989 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 990 ** handled as a fatal error by SQLite, vfs implementations should endeavor 991 ** to prevent this by setting mxPathname to a sufficiently large value. 992 ** 993 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 994 ** interfaces are not strictly a part of the filesystem, but they are 995 ** included in the VFS structure for completeness. 996 ** The xRandomness() function attempts to return nBytes bytes 997 ** of good-quality randomness into zOut. The return value is 998 ** the actual number of bytes of randomness obtained. 999 ** The xSleep() method causes the calling thread to sleep for at 1000 ** least the number of microseconds given. ^The xCurrentTime() 1001 ** method returns a Julian Day Number for the current date and time as 1002 ** a floating point value. 1003 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1004 ** Day Number multiplied by 86400000 (the number of milliseconds in 1005 ** a 24-hour day). 1006 ** ^SQLite will use the xCurrentTimeInt64() method to get the current 1007 ** date and time if that method is available (if iVersion is 2 or 1008 ** greater and the function pointer is not NULL) and will fall back 1009 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1010 ** 1011 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1012 ** are not used by the SQLite core. These optional interfaces are provided 1013 ** by some VFSes to facilitate testing of the VFS code. By overriding 1014 ** system calls with functions under its control, a test program can 1015 ** simulate faults and error conditions that would otherwise be difficult 1016 ** or impossible to induce. The set of system calls that can be overridden 1017 ** varies from one VFS to another, and from one version of the same VFS to the 1018 ** next. Applications that use these interfaces must be prepared for any 1019 ** or all of these interfaces to be NULL or for their behavior to change 1020 ** from one release to the next. Applications must not attempt to access 1021 ** any of these methods if the iVersion of the VFS is less than 3. 1022 */ 1023 typedef struct sqlite3_vfs sqlite3_vfs; 1024 typedef void (*sqlite3_syscall_ptr)(void); 1025 struct sqlite3_vfs { 1026 int iVersion; /* Structure version number (currently 3) */ 1027 int szOsFile; /* Size of subclassed sqlite3_file */ 1028 int mxPathname; /* Maximum file pathname length */ 1029 sqlite3_vfs *pNext; /* Next registered VFS */ 1030 const char *zName; /* Name of this virtual file system */ 1031 void *pAppData; /* Pointer to application-specific data */ 1032 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1033 int flags, int *pOutFlags); 1034 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1035 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1036 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1037 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1038 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1039 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1040 void (*xDlClose)(sqlite3_vfs*, void*); 1041 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1042 int (*xSleep)(sqlite3_vfs*, int microseconds); 1043 int (*xCurrentTime)(sqlite3_vfs*, double*); 1044 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1045 /* 1046 ** The methods above are in version 1 of the sqlite_vfs object 1047 ** definition. Those that follow are added in version 2 or later 1048 */ 1049 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1050 /* 1051 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1052 ** Those below are for version 3 and greater. 1053 */ 1054 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1055 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1056 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1057 /* 1058 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1059 ** New fields may be appended in figure versions. The iVersion 1060 ** value will increment whenever this happens. 1061 */ 1062 }; 1063 1064 /* 1065 ** CAPI3REF: Flags for the xAccess VFS method 1066 ** 1067 ** These integer constants can be used as the third parameter to 1068 ** the xAccess method of an [sqlite3_vfs] object. They determine 1069 ** what kind of permissions the xAccess method is looking for. 1070 ** With SQLITE_ACCESS_EXISTS, the xAccess method 1071 ** simply checks whether the file exists. 1072 ** With SQLITE_ACCESS_READWRITE, the xAccess method 1073 ** checks whether the named directory is both readable and writable 1074 ** (in other words, if files can be added, removed, and renamed within 1075 ** the directory). 1076 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1077 ** [temp_store_directory pragma], though this could change in a future 1078 ** release of SQLite. 1079 ** With SQLITE_ACCESS_READ, the xAccess method 1080 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1081 ** currently unused, though it might be used in a future release of 1082 ** SQLite. 1083 */ 1084 #define SQLITE_ACCESS_EXISTS 0 1085 #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1086 #define SQLITE_ACCESS_READ 2 /* Unused */ 1087 1088 /* 1089 ** CAPI3REF: Flags for the xShmLock VFS method 1090 ** 1091 ** These integer constants define the various locking operations 1092 ** allowed by the xShmLock method of [sqlite3_io_methods]. The 1093 ** following are the only legal combinations of flags to the 1094 ** xShmLock method: 1095 ** 1096 ** <ul> 1097 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1098 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1099 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1100 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1101 ** </ul> 1102 ** 1103 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1104 ** was given no the corresponding lock. 1105 ** 1106 ** The xShmLock method can transition between unlocked and SHARED or 1107 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1108 ** and EXCLUSIVE. 1109 */ 1110 #define SQLITE_SHM_UNLOCK 1 1111 #define SQLITE_SHM_LOCK 2 1112 #define SQLITE_SHM_SHARED 4 1113 #define SQLITE_SHM_EXCLUSIVE 8 1114 1115 /* 1116 ** CAPI3REF: Maximum xShmLock index 1117 ** 1118 ** The xShmLock method on [sqlite3_io_methods] may use values 1119 ** between 0 and this upper bound as its "offset" argument. 1120 ** The SQLite core will never attempt to acquire or release a 1121 ** lock outside of this range 1122 */ 1123 #define SQLITE_SHM_NLOCK 8 1124 1125 1126 /* 1127 ** CAPI3REF: Initialize The SQLite Library 1128 ** 1129 ** ^The sqlite3_initialize() routine initializes the 1130 ** SQLite library. ^The sqlite3_shutdown() routine 1131 ** deallocates any resources that were allocated by sqlite3_initialize(). 1132 ** These routines are designed to aid in process initialization and 1133 ** shutdown on embedded systems. Workstation applications using 1134 ** SQLite normally do not need to invoke either of these routines. 1135 ** 1136 ** A call to sqlite3_initialize() is an "effective" call if it is 1137 ** the first time sqlite3_initialize() is invoked during the lifetime of 1138 ** the process, or if it is the first time sqlite3_initialize() is invoked 1139 ** following a call to sqlite3_shutdown(). ^(Only an effective call 1140 ** of sqlite3_initialize() does any initialization. All other calls 1141 ** are harmless no-ops.)^ 1142 ** 1143 ** A call to sqlite3_shutdown() is an "effective" call if it is the first 1144 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1145 ** an effective call to sqlite3_shutdown() does any deinitialization. 1146 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1147 ** 1148 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1149 ** is not. The sqlite3_shutdown() interface must only be called from a 1150 ** single thread. All open [database connections] must be closed and all 1151 ** other SQLite resources must be deallocated prior to invoking 1152 ** sqlite3_shutdown(). 1153 ** 1154 ** Among other things, ^sqlite3_initialize() will invoke 1155 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1156 ** will invoke sqlite3_os_end(). 1157 ** 1158 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1159 ** ^If for some reason, sqlite3_initialize() is unable to initialize 1160 ** the library (perhaps it is unable to allocate a needed resource such 1161 ** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1162 ** 1163 ** ^The sqlite3_initialize() routine is called internally by many other 1164 ** SQLite interfaces so that an application usually does not need to 1165 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1166 ** calls sqlite3_initialize() so the SQLite library will be automatically 1167 ** initialized when [sqlite3_open()] is called if it has not be initialized 1168 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1169 ** compile-time option, then the automatic calls to sqlite3_initialize() 1170 ** are omitted and the application must call sqlite3_initialize() directly 1171 ** prior to using any other SQLite interface. For maximum portability, 1172 ** it is recommended that applications always invoke sqlite3_initialize() 1173 ** directly prior to using any other SQLite interface. Future releases 1174 ** of SQLite may require this. In other words, the behavior exhibited 1175 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1176 ** default behavior in some future release of SQLite. 1177 ** 1178 ** The sqlite3_os_init() routine does operating-system specific 1179 ** initialization of the SQLite library. The sqlite3_os_end() 1180 ** routine undoes the effect of sqlite3_os_init(). Typical tasks 1181 ** performed by these routines include allocation or deallocation 1182 ** of static resources, initialization of global variables, 1183 ** setting up a default [sqlite3_vfs] module, or setting up 1184 ** a default configuration using [sqlite3_config()]. 1185 ** 1186 ** The application should never invoke either sqlite3_os_init() 1187 ** or sqlite3_os_end() directly. The application should only invoke 1188 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1189 ** interface is called automatically by sqlite3_initialize() and 1190 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1191 ** implementations for sqlite3_os_init() and sqlite3_os_end() 1192 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1193 ** When [custom builds | built for other platforms] 1194 ** (using the [SQLITE_OS_OTHER=1] compile-time 1195 ** option) the application must supply a suitable implementation for 1196 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1197 ** implementation of sqlite3_os_init() or sqlite3_os_end() 1198 ** must return [SQLITE_OK] on success and some other [error code] upon 1199 ** failure. 1200 */ 1201 SQLITE_API int sqlite3_initialize(void); 1202 SQLITE_API int sqlite3_shutdown(void); 1203 SQLITE_API int sqlite3_os_init(void); 1204 SQLITE_API int sqlite3_os_end(void); 1205 1206 /* 1207 ** CAPI3REF: Configuring The SQLite Library 1208 ** 1209 ** The sqlite3_config() interface is used to make global configuration 1210 ** changes to SQLite in order to tune SQLite to the specific needs of 1211 ** the application. The default configuration is recommended for most 1212 ** applications and so this routine is usually not necessary. It is 1213 ** provided to support rare applications with unusual needs. 1214 ** 1215 ** The sqlite3_config() interface is not threadsafe. The application 1216 ** must insure that no other SQLite interfaces are invoked by other 1217 ** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1218 ** may only be invoked prior to library initialization using 1219 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1220 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1221 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1222 ** Note, however, that ^sqlite3_config() can be called as part of the 1223 ** implementation of an application-defined [sqlite3_os_init()]. 1224 ** 1225 ** The first argument to sqlite3_config() is an integer 1226 ** [configuration option] that determines 1227 ** what property of SQLite is to be configured. Subsequent arguments 1228 ** vary depending on the [configuration option] 1229 ** in the first argument. 1230 ** 1231 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1232 ** ^If the option is unknown or SQLite is unable to set the option 1233 ** then this routine returns a non-zero [error code]. 1234 */ 1235 SQLITE_API int sqlite3_config(int, ...); 1236 1237 /* 1238 ** CAPI3REF: Configure database connections 1239 ** 1240 ** The sqlite3_db_config() interface is used to make configuration 1241 ** changes to a [database connection]. The interface is similar to 1242 ** [sqlite3_config()] except that the changes apply to a single 1243 ** [database connection] (specified in the first argument). 1244 ** 1245 ** The second argument to sqlite3_db_config(D,V,...) is the 1246 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1247 ** that indicates what aspect of the [database connection] is being configured. 1248 ** Subsequent arguments vary depending on the configuration verb. 1249 ** 1250 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1251 ** the call is considered successful. 1252 */ 1253 SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...); 1254 1255 /* 1256 ** CAPI3REF: Memory Allocation Routines 1257 ** 1258 ** An instance of this object defines the interface between SQLite 1259 ** and low-level memory allocation routines. 1260 ** 1261 ** This object is used in only one place in the SQLite interface. 1262 ** A pointer to an instance of this object is the argument to 1263 ** [sqlite3_config()] when the configuration option is 1264 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1265 ** By creating an instance of this object 1266 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1267 ** during configuration, an application can specify an alternative 1268 ** memory allocation subsystem for SQLite to use for all of its 1269 ** dynamic memory needs. 1270 ** 1271 ** Note that SQLite comes with several [built-in memory allocators] 1272 ** that are perfectly adequate for the overwhelming majority of applications 1273 ** and that this object is only useful to a tiny minority of applications 1274 ** with specialized memory allocation requirements. This object is 1275 ** also used during testing of SQLite in order to specify an alternative 1276 ** memory allocator that simulates memory out-of-memory conditions in 1277 ** order to verify that SQLite recovers gracefully from such 1278 ** conditions. 1279 ** 1280 ** The xMalloc, xRealloc, and xFree methods must work like the 1281 ** malloc(), realloc() and free() functions from the standard C library. 1282 ** ^SQLite guarantees that the second argument to 1283 ** xRealloc is always a value returned by a prior call to xRoundup. 1284 ** 1285 ** xSize should return the allocated size of a memory allocation 1286 ** previously obtained from xMalloc or xRealloc. The allocated size 1287 ** is always at least as big as the requested size but may be larger. 1288 ** 1289 ** The xRoundup method returns what would be the allocated size of 1290 ** a memory allocation given a particular requested size. Most memory 1291 ** allocators round up memory allocations at least to the next multiple 1292 ** of 8. Some allocators round up to a larger multiple or to a power of 2. 1293 ** Every memory allocation request coming in through [sqlite3_malloc()] 1294 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1295 ** that causes the corresponding memory allocation to fail. 1296 ** 1297 ** The xInit method initializes the memory allocator. (For example, 1298 ** it might allocate any require mutexes or initialize internal data 1299 ** structures. The xShutdown method is invoked (indirectly) by 1300 ** [sqlite3_shutdown()] and should deallocate any resources acquired 1301 ** by xInit. The pAppData pointer is used as the only parameter to 1302 ** xInit and xShutdown. 1303 ** 1304 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1305 ** the xInit method, so the xInit method need not be threadsafe. The 1306 ** xShutdown method is only called from [sqlite3_shutdown()] so it does 1307 ** not need to be threadsafe either. For all other methods, SQLite 1308 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1309 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1310 ** it is by default) and so the methods are automatically serialized. 1311 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1312 ** methods must be threadsafe or else make their own arrangements for 1313 ** serialization. 1314 ** 1315 ** SQLite will never invoke xInit() more than once without an intervening 1316 ** call to xShutdown(). 1317 */ 1318 typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1319 struct sqlite3_mem_methods { 1320 void *(*xMalloc)(int); /* Memory allocation function */ 1321 void (*xFree)(void*); /* Free a prior allocation */ 1322 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1323 int (*xSize)(void*); /* Return the size of an allocation */ 1324 int (*xRoundup)(int); /* Round up request size to allocation size */ 1325 int (*xInit)(void*); /* Initialize the memory allocator */ 1326 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1327 void *pAppData; /* Argument to xInit() and xShutdown() */ 1328 }; 1329 1330 /* 1331 ** CAPI3REF: Configuration Options 1332 ** KEYWORDS: {configuration option} 1333 ** 1334 ** These constants are the available integer configuration options that 1335 ** can be passed as the first argument to the [sqlite3_config()] interface. 1336 ** 1337 ** New configuration options may be added in future releases of SQLite. 1338 ** Existing configuration options might be discontinued. Applications 1339 ** should check the return code from [sqlite3_config()] to make sure that 1340 ** the call worked. The [sqlite3_config()] interface will return a 1341 ** non-zero [error code] if a discontinued or unsupported configuration option 1342 ** is invoked. 1343 ** 1344 ** <dl> 1345 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1346 ** <dd>There are no arguments to this option. ^This option sets the 1347 ** [threading mode] to Single-thread. In other words, it disables 1348 ** all mutexing and puts SQLite into a mode where it can only be used 1349 ** by a single thread. ^If SQLite is compiled with 1350 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1351 ** it is not possible to change the [threading mode] from its default 1352 ** value of Single-thread and so [sqlite3_config()] will return 1353 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1354 ** configuration option.</dd> 1355 ** 1356 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1357 ** <dd>There are no arguments to this option. ^This option sets the 1358 ** [threading mode] to Multi-thread. In other words, it disables 1359 ** mutexing on [database connection] and [prepared statement] objects. 1360 ** The application is responsible for serializing access to 1361 ** [database connections] and [prepared statements]. But other mutexes 1362 ** are enabled so that SQLite will be safe to use in a multi-threaded 1363 ** environment as long as no two threads attempt to use the same 1364 ** [database connection] at the same time. ^If SQLite is compiled with 1365 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1366 ** it is not possible to set the Multi-thread [threading mode] and 1367 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1368 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1369 ** 1370 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1371 ** <dd>There are no arguments to this option. ^This option sets the 1372 ** [threading mode] to Serialized. In other words, this option enables 1373 ** all mutexes including the recursive 1374 ** mutexes on [database connection] and [prepared statement] objects. 1375 ** In this mode (which is the default when SQLite is compiled with 1376 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1377 ** to [database connections] and [prepared statements] so that the 1378 ** application is free to use the same [database connection] or the 1379 ** same [prepared statement] in different threads at the same time. 1380 ** ^If SQLite is compiled with 1381 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1382 ** it is not possible to set the Serialized [threading mode] and 1383 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1384 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1385 ** 1386 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1387 ** <dd> ^(This option takes a single argument which is a pointer to an 1388 ** instance of the [sqlite3_mem_methods] structure. The argument specifies 1389 ** alternative low-level memory allocation routines to be used in place of 1390 ** the memory allocation routines built into SQLite.)^ ^SQLite makes 1391 ** its own private copy of the content of the [sqlite3_mem_methods] structure 1392 ** before the [sqlite3_config()] call returns.</dd> 1393 ** 1394 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1395 ** <dd> ^(This option takes a single argument which is a pointer to an 1396 ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1397 ** structure is filled with the currently defined memory allocation routines.)^ 1398 ** This option can be used to overload the default memory allocation 1399 ** routines with a wrapper that simulations memory allocation failure or 1400 ** tracks memory usage, for example. </dd> 1401 ** 1402 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1403 ** <dd> ^This option takes single argument of type int, interpreted as a 1404 ** boolean, which enables or disables the collection of memory allocation 1405 ** statistics. ^(When memory allocation statistics are disabled, the 1406 ** following SQLite interfaces become non-operational: 1407 ** <ul> 1408 ** <li> [sqlite3_memory_used()] 1409 ** <li> [sqlite3_memory_highwater()] 1410 ** <li> [sqlite3_soft_heap_limit64()] 1411 ** <li> [sqlite3_status()] 1412 ** </ul>)^ 1413 ** ^Memory allocation statistics are enabled by default unless SQLite is 1414 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1415 ** allocation statistics are disabled by default. 1416 ** </dd> 1417 ** 1418 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1419 ** <dd> ^This option specifies a static memory buffer that SQLite can use for 1420 ** scratch memory. There are three arguments: A pointer an 8-byte 1421 ** aligned memory buffer from which the scratch allocations will be 1422 ** drawn, the size of each scratch allocation (sz), 1423 ** and the maximum number of scratch allocations (N). The sz 1424 ** argument must be a multiple of 16. 1425 ** The first argument must be a pointer to an 8-byte aligned buffer 1426 ** of at least sz*N bytes of memory. 1427 ** ^SQLite will use no more than two scratch buffers per thread. So 1428 ** N should be set to twice the expected maximum number of threads. 1429 ** ^SQLite will never require a scratch buffer that is more than 6 1430 ** times the database page size. ^If SQLite needs needs additional 1431 ** scratch memory beyond what is provided by this configuration option, then 1432 ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1433 ** 1434 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1435 ** <dd> ^This option specifies a static memory buffer that SQLite can use for 1436 ** the database page cache with the default page cache implementation. 1437 ** This configuration should not be used if an application-define page 1438 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option. 1439 ** There are three arguments to this option: A pointer to 8-byte aligned 1440 ** memory, the size of each page buffer (sz), and the number of pages (N). 1441 ** The sz argument should be the size of the largest database page 1442 ** (a power of two between 512 and 32768) plus a little extra for each 1443 ** page header. ^The page header size is 20 to 40 bytes depending on 1444 ** the host architecture. ^It is harmless, apart from the wasted memory, 1445 ** to make sz a little too large. The first 1446 ** argument should point to an allocation of at least sz*N bytes of memory. 1447 ** ^SQLite will use the memory provided by the first argument to satisfy its 1448 ** memory needs for the first N pages that it adds to cache. ^If additional 1449 ** page cache memory is needed beyond what is provided by this option, then 1450 ** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1451 ** The pointer in the first argument must 1452 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1453 ** will be undefined.</dd> 1454 ** 1455 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1456 ** <dd> ^This option specifies a static memory buffer that SQLite will use 1457 ** for all of its dynamic memory allocation needs beyond those provided 1458 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1459 ** There are three arguments: An 8-byte aligned pointer to the memory, 1460 ** the number of bytes in the memory buffer, and the minimum allocation size. 1461 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1462 ** to using its default memory allocator (the system malloc() implementation), 1463 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1464 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1465 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1466 ** allocator is engaged to handle all of SQLites memory allocation needs. 1467 ** The first pointer (the memory pointer) must be aligned to an 8-byte 1468 ** boundary or subsequent behavior of SQLite will be undefined. 1469 ** The minimum allocation size is capped at 2**12. Reasonable values 1470 ** for the minimum allocation size are 2**5 through 2**8.</dd> 1471 ** 1472 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1473 ** <dd> ^(This option takes a single argument which is a pointer to an 1474 ** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1475 ** alternative low-level mutex routines to be used in place 1476 ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1477 ** content of the [sqlite3_mutex_methods] structure before the call to 1478 ** [sqlite3_config()] returns. ^If SQLite is compiled with 1479 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1480 ** the entire mutexing subsystem is omitted from the build and hence calls to 1481 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1482 ** return [SQLITE_ERROR].</dd> 1483 ** 1484 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1485 ** <dd> ^(This option takes a single argument which is a pointer to an 1486 ** instance of the [sqlite3_mutex_methods] structure. The 1487 ** [sqlite3_mutex_methods] 1488 ** structure is filled with the currently defined mutex routines.)^ 1489 ** This option can be used to overload the default mutex allocation 1490 ** routines with a wrapper used to track mutex usage for performance 1491 ** profiling or testing, for example. ^If SQLite is compiled with 1492 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1493 ** the entire mutexing subsystem is omitted from the build and hence calls to 1494 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1495 ** return [SQLITE_ERROR].</dd> 1496 ** 1497 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1498 ** <dd> ^(This option takes two arguments that determine the default 1499 ** memory allocation for the lookaside memory allocator on each 1500 ** [database connection]. The first argument is the 1501 ** size of each lookaside buffer slot and the second is the number of 1502 ** slots allocated to each database connection.)^ ^(This option sets the 1503 ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1504 ** verb to [sqlite3_db_config()] can be used to change the lookaside 1505 ** configuration on individual connections.)^ </dd> 1506 ** 1507 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1508 ** <dd> ^(This option takes a single argument which is a pointer to 1509 ** an [sqlite3_pcache_methods2] object. This object specifies the interface 1510 ** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1511 ** object and uses it for page cache memory allocations.</dd> 1512 ** 1513 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1514 ** <dd> ^(This option takes a single argument which is a pointer to an 1515 ** [sqlite3_pcache_methods2] object. SQLite copies of the current 1516 ** page cache implementation into that object.)^ </dd> 1517 ** 1518 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1519 ** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1520 ** function with a call signature of void(*)(void*,int,const char*), 1521 ** and a pointer to void. ^If the function pointer is not NULL, it is 1522 ** invoked by [sqlite3_log()] to process each logging event. ^If the 1523 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1524 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1525 ** passed through as the first parameter to the application-defined logger 1526 ** function whenever that function is invoked. ^The second parameter to 1527 ** the logger function is a copy of the first parameter to the corresponding 1528 ** [sqlite3_log()] call and is intended to be a [result code] or an 1529 ** [extended result code]. ^The third parameter passed to the logger is 1530 ** log message after formatting via [sqlite3_snprintf()]. 1531 ** The SQLite logging interface is not reentrant; the logger function 1532 ** supplied by the application must not invoke any SQLite interface. 1533 ** In a multi-threaded application, the application-defined logger 1534 ** function must be threadsafe. </dd> 1535 ** 1536 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1537 ** <dd> This option takes a single argument of type int. If non-zero, then 1538 ** URI handling is globally enabled. If the parameter is zero, then URI handling 1539 ** is globally disabled. If URI handling is globally enabled, all filenames 1540 ** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or 1541 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1542 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1543 ** connection is opened. If it is globally disabled, filenames are 1544 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1545 ** database connection is opened. By default, URI handling is globally 1546 ** disabled. The default value may be changed by compiling with the 1547 ** [SQLITE_USE_URI] symbol defined. 1548 ** 1549 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1550 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFNIG_GETPCACHE 1551 ** <dd> These options are obsolete and should not be used by new code. 1552 ** They are retained for backwards compatibility but are now no-ops. 1553 ** </dl> 1554 */ 1555 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1556 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1557 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1558 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1559 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1560 #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1561 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1562 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1563 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1564 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1565 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1566 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1567 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1568 #define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1569 #define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1570 #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1571 #define SQLITE_CONFIG_URI 17 /* int */ 1572 #define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1573 #define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1574 1575 /* 1576 ** CAPI3REF: Database Connection Configuration Options 1577 ** 1578 ** These constants are the available integer configuration options that 1579 ** can be passed as the second argument to the [sqlite3_db_config()] interface. 1580 ** 1581 ** New configuration options may be added in future releases of SQLite. 1582 ** Existing configuration options might be discontinued. Applications 1583 ** should check the return code from [sqlite3_db_config()] to make sure that 1584 ** the call worked. ^The [sqlite3_db_config()] interface will return a 1585 ** non-zero [error code] if a discontinued or unsupported configuration option 1586 ** is invoked. 1587 ** 1588 ** <dl> 1589 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1590 ** <dd> ^This option takes three additional arguments that determine the 1591 ** [lookaside memory allocator] configuration for the [database connection]. 1592 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1593 ** pointer to a memory buffer to use for lookaside memory. 1594 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1595 ** may be NULL in which case SQLite will allocate the 1596 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1597 ** size of each lookaside buffer slot. ^The third argument is the number of 1598 ** slots. The size of the buffer in the first argument must be greater than 1599 ** or equal to the product of the second and third arguments. The buffer 1600 ** must be aligned to an 8-byte boundary. ^If the second argument to 1601 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1602 ** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1603 ** configuration for a database connection can only be changed when that 1604 ** connection is not currently using lookaside memory, or in other words 1605 ** when the "current value" returned by 1606 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1607 ** Any attempt to change the lookaside memory configuration when lookaside 1608 ** memory is in use leaves the configuration unchanged and returns 1609 ** [SQLITE_BUSY].)^</dd> 1610 ** 1611 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1612 ** <dd> ^This option is used to enable or disable the enforcement of 1613 ** [foreign key constraints]. There should be two additional arguments. 1614 ** The first argument is an integer which is 0 to disable FK enforcement, 1615 ** positive to enable FK enforcement or negative to leave FK enforcement 1616 ** unchanged. The second parameter is a pointer to an integer into which 1617 ** is written 0 or 1 to indicate whether FK enforcement is off or on 1618 ** following this call. The second parameter may be a NULL pointer, in 1619 ** which case the FK enforcement setting is not reported back. </dd> 1620 ** 1621 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1622 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1623 ** There should be two additional arguments. 1624 ** The first argument is an integer which is 0 to disable triggers, 1625 ** positive to enable triggers or negative to leave the setting unchanged. 1626 ** The second parameter is a pointer to an integer into which 1627 ** is written 0 or 1 to indicate whether triggers are disabled or enabled 1628 ** following this call. The second parameter may be a NULL pointer, in 1629 ** which case the trigger setting is not reported back. </dd> 1630 ** 1631 ** </dl> 1632 */ 1633 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1634 #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1635 #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1636 1637 1638 /* 1639 ** CAPI3REF: Enable Or Disable Extended Result Codes 1640 ** 1641 ** ^The sqlite3_extended_result_codes() routine enables or disables the 1642 ** [extended result codes] feature of SQLite. ^The extended result 1643 ** codes are disabled by default for historical compatibility. 1644 */ 1645 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff); 1646 1647 /* 1648 ** CAPI3REF: Last Insert Rowid 1649 ** 1650 ** ^Each entry in an SQLite table has a unique 64-bit signed 1651 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1652 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1653 ** names are not also used by explicitly declared columns. ^If 1654 ** the table has a column of type [INTEGER PRIMARY KEY] then that column 1655 ** is another alias for the rowid. 1656 ** 1657 ** ^This routine returns the [rowid] of the most recent 1658 ** successful [INSERT] into the database from the [database connection] 1659 ** in the first argument. ^As of SQLite version 3.7.7, this routines 1660 ** records the last insert rowid of both ordinary tables and [virtual tables]. 1661 ** ^If no successful [INSERT]s 1662 ** have ever occurred on that database connection, zero is returned. 1663 ** 1664 ** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1665 ** method, then this routine will return the [rowid] of the inserted 1666 ** row as long as the trigger or virtual table method is running. 1667 ** But once the trigger or virtual table method ends, the value returned 1668 ** by this routine reverts to what it was before the trigger or virtual 1669 ** table method began.)^ 1670 ** 1671 ** ^An [INSERT] that fails due to a constraint violation is not a 1672 ** successful [INSERT] and does not change the value returned by this 1673 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1674 ** and INSERT OR ABORT make no changes to the return value of this 1675 ** routine when their insertion fails. ^(When INSERT OR REPLACE 1676 ** encounters a constraint violation, it does not fail. The 1677 ** INSERT continues to completion after deleting rows that caused 1678 ** the constraint problem so INSERT OR REPLACE will always change 1679 ** the return value of this interface.)^ 1680 ** 1681 ** ^For the purposes of this routine, an [INSERT] is considered to 1682 ** be successful even if it is subsequently rolled back. 1683 ** 1684 ** This function is accessible to SQL statements via the 1685 ** [last_insert_rowid() SQL function]. 1686 ** 1687 ** If a separate thread performs a new [INSERT] on the same 1688 ** database connection while the [sqlite3_last_insert_rowid()] 1689 ** function is running and thus changes the last insert [rowid], 1690 ** then the value returned by [sqlite3_last_insert_rowid()] is 1691 ** unpredictable and might not equal either the old or the new 1692 ** last insert [rowid]. 1693 */ 1694 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1695 1696 /* 1697 ** CAPI3REF: Count The Number Of Rows Modified 1698 ** 1699 ** ^This function returns the number of database rows that were changed 1700 ** or inserted or deleted by the most recently completed SQL statement 1701 ** on the [database connection] specified by the first parameter. 1702 ** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1703 ** or [DELETE] statement are counted. Auxiliary changes caused by 1704 ** triggers or [foreign key actions] are not counted.)^ Use the 1705 ** [sqlite3_total_changes()] function to find the total number of changes 1706 ** including changes caused by triggers and foreign key actions. 1707 ** 1708 ** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1709 ** are not counted. Only real table changes are counted. 1710 ** 1711 ** ^(A "row change" is a change to a single row of a single table 1712 ** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1713 ** are changed as side effects of [REPLACE] constraint resolution, 1714 ** rollback, ABORT processing, [DROP TABLE], or by any other 1715 ** mechanisms do not count as direct row changes.)^ 1716 ** 1717 ** A "trigger context" is a scope of execution that begins and 1718 ** ends with the script of a [CREATE TRIGGER | trigger]. 1719 ** Most SQL statements are 1720 ** evaluated outside of any trigger. This is the "top level" 1721 ** trigger context. If a trigger fires from the top level, a 1722 ** new trigger context is entered for the duration of that one 1723 ** trigger. Subtriggers create subcontexts for their duration. 1724 ** 1725 ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1726 ** not create a new trigger context. 1727 ** 1728 ** ^This function returns the number of direct row changes in the 1729 ** most recent INSERT, UPDATE, or DELETE statement within the same 1730 ** trigger context. 1731 ** 1732 ** ^Thus, when called from the top level, this function returns the 1733 ** number of changes in the most recent INSERT, UPDATE, or DELETE 1734 ** that also occurred at the top level. ^(Within the body of a trigger, 1735 ** the sqlite3_changes() interface can be called to find the number of 1736 ** changes in the most recently completed INSERT, UPDATE, or DELETE 1737 ** statement within the body of the same trigger. 1738 ** However, the number returned does not include changes 1739 ** caused by subtriggers since those have their own context.)^ 1740 ** 1741 ** See also the [sqlite3_total_changes()] interface, the 1742 ** [count_changes pragma], and the [changes() SQL function]. 1743 ** 1744 ** If a separate thread makes changes on the same database connection 1745 ** while [sqlite3_changes()] is running then the value returned 1746 ** is unpredictable and not meaningful. 1747 */ 1748 SQLITE_API int sqlite3_changes(sqlite3*); 1749 1750 /* 1751 ** CAPI3REF: Total Number Of Rows Modified 1752 ** 1753 ** ^This function returns the number of row changes caused by [INSERT], 1754 ** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1755 ** ^(The count returned by sqlite3_total_changes() includes all changes 1756 ** from all [CREATE TRIGGER | trigger] contexts and changes made by 1757 ** [foreign key actions]. However, 1758 ** the count does not include changes used to implement [REPLACE] constraints, 1759 ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1760 ** count does not include rows of views that fire an [INSTEAD OF trigger], 1761 ** though if the INSTEAD OF trigger makes changes of its own, those changes 1762 ** are counted.)^ 1763 ** ^The sqlite3_total_changes() function counts the changes as soon as 1764 ** the statement that makes them is completed (when the statement handle 1765 ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1766 ** 1767 ** See also the [sqlite3_changes()] interface, the 1768 ** [count_changes pragma], and the [total_changes() SQL function]. 1769 ** 1770 ** If a separate thread makes changes on the same database connection 1771 ** while [sqlite3_total_changes()] is running then the value 1772 ** returned is unpredictable and not meaningful. 1773 */ 1774 SQLITE_API int sqlite3_total_changes(sqlite3*); 1775 1776 /* 1777 ** CAPI3REF: Interrupt A Long-Running Query 1778 ** 1779 ** ^This function causes any pending database operation to abort and 1780 ** return at its earliest opportunity. This routine is typically 1781 ** called in response to a user action such as pressing "Cancel" 1782 ** or Ctrl-C where the user wants a long query operation to halt 1783 ** immediately. 1784 ** 1785 ** ^It is safe to call this routine from a thread different from the 1786 ** thread that is currently running the database operation. But it 1787 ** is not safe to call this routine with a [database connection] that 1788 ** is closed or might close before sqlite3_interrupt() returns. 1789 ** 1790 ** ^If an SQL operation is very nearly finished at the time when 1791 ** sqlite3_interrupt() is called, then it might not have an opportunity 1792 ** to be interrupted and might continue to completion. 1793 ** 1794 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1795 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1796 ** that is inside an explicit transaction, then the entire transaction 1797 ** will be rolled back automatically. 1798 ** 1799 ** ^The sqlite3_interrupt(D) call is in effect until all currently running 1800 ** SQL statements on [database connection] D complete. ^Any new SQL statements 1801 ** that are started after the sqlite3_interrupt() call and before the 1802 ** running statements reaches zero are interrupted as if they had been 1803 ** running prior to the sqlite3_interrupt() call. ^New SQL statements 1804 ** that are started after the running statement count reaches zero are 1805 ** not effected by the sqlite3_interrupt(). 1806 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1807 ** SQL statements is a no-op and has no effect on SQL statements 1808 ** that are started after the sqlite3_interrupt() call returns. 1809 ** 1810 ** If the database connection closes while [sqlite3_interrupt()] 1811 ** is running then bad things will likely happen. 1812 */ 1813 SQLITE_API void sqlite3_interrupt(sqlite3*); 1814 1815 /* 1816 ** CAPI3REF: Determine If An SQL Statement Is Complete 1817 ** 1818 ** These routines are useful during command-line input to determine if the 1819 ** currently entered text seems to form a complete SQL statement or 1820 ** if additional input is needed before sending the text into 1821 ** SQLite for parsing. ^These routines return 1 if the input string 1822 ** appears to be a complete SQL statement. ^A statement is judged to be 1823 ** complete if it ends with a semicolon token and is not a prefix of a 1824 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1825 ** string literals or quoted identifier names or comments are not 1826 ** independent tokens (they are part of the token in which they are 1827 ** embedded) and thus do not count as a statement terminator. ^Whitespace 1828 ** and comments that follow the final semicolon are ignored. 1829 ** 1830 ** ^These routines return 0 if the statement is incomplete. ^If a 1831 ** memory allocation fails, then SQLITE_NOMEM is returned. 1832 ** 1833 ** ^These routines do not parse the SQL statements thus 1834 ** will not detect syntactically incorrect SQL. 1835 ** 1836 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1837 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1838 ** automatically by sqlite3_complete16(). If that initialization fails, 1839 ** then the return value from sqlite3_complete16() will be non-zero 1840 ** regardless of whether or not the input SQL is complete.)^ 1841 ** 1842 ** The input to [sqlite3_complete()] must be a zero-terminated 1843 ** UTF-8 string. 1844 ** 1845 ** The input to [sqlite3_complete16()] must be a zero-terminated 1846 ** UTF-16 string in native byte order. 1847 */ 1848 SQLITE_API int sqlite3_complete(const char *sql); 1849 SQLITE_API int sqlite3_complete16(const void *sql); 1850 1851 /* 1852 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1853 ** 1854 ** ^This routine sets a callback function that might be invoked whenever 1855 ** an attempt is made to open a database table that another thread 1856 ** or process has locked. 1857 ** 1858 ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1859 ** is returned immediately upon encountering the lock. ^If the busy callback 1860 ** is not NULL, then the callback might be invoked with two arguments. 1861 ** 1862 ** ^The first argument to the busy handler is a copy of the void* pointer which 1863 ** is the third argument to sqlite3_busy_handler(). ^The second argument to 1864 ** the busy handler callback is the number of times that the busy handler has 1865 ** been invoked for this locking event. ^If the 1866 ** busy callback returns 0, then no additional attempts are made to 1867 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1868 ** ^If the callback returns non-zero, then another attempt 1869 ** is made to open the database for reading and the cycle repeats. 1870 ** 1871 ** The presence of a busy handler does not guarantee that it will be invoked 1872 ** when there is lock contention. ^If SQLite determines that invoking the busy 1873 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1874 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1875 ** Consider a scenario where one process is holding a read lock that 1876 ** it is trying to promote to a reserved lock and 1877 ** a second process is holding a reserved lock that it is trying 1878 ** to promote to an exclusive lock. The first process cannot proceed 1879 ** because it is blocked by the second and the second process cannot 1880 ** proceed because it is blocked by the first. If both processes 1881 ** invoke the busy handlers, neither will make any progress. Therefore, 1882 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1883 ** will induce the first process to release its read lock and allow 1884 ** the second process to proceed. 1885 ** 1886 ** ^The default busy callback is NULL. 1887 ** 1888 ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1889 ** when SQLite is in the middle of a large transaction where all the 1890 ** changes will not fit into the in-memory cache. SQLite will 1891 ** already hold a RESERVED lock on the database file, but it needs 1892 ** to promote this lock to EXCLUSIVE so that it can spill cache 1893 ** pages into the database file without harm to concurrent 1894 ** readers. ^If it is unable to promote the lock, then the in-memory 1895 ** cache will be left in an inconsistent state and so the error 1896 ** code is promoted from the relatively benign [SQLITE_BUSY] to 1897 ** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 1898 ** forces an automatic rollback of the changes. See the 1899 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1900 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1901 ** this is important. 1902 ** 1903 ** ^(There can only be a single busy handler defined for each 1904 ** [database connection]. Setting a new busy handler clears any 1905 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 1906 ** will also set or clear the busy handler. 1907 ** 1908 ** The busy callback should not take any actions which modify the 1909 ** database connection that invoked the busy handler. Any such actions 1910 ** result in undefined behavior. 1911 ** 1912 ** A busy handler must not close the database connection 1913 ** or [prepared statement] that invoked the busy handler. 1914 */ 1915 SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1916 1917 /* 1918 ** CAPI3REF: Set A Busy Timeout 1919 ** 1920 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1921 ** for a specified amount of time when a table is locked. ^The handler 1922 ** will sleep multiple times until at least "ms" milliseconds of sleeping 1923 ** have accumulated. ^After at least "ms" milliseconds of sleeping, 1924 ** the handler returns 0 which causes [sqlite3_step()] to return 1925 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1926 ** 1927 ** ^Calling this routine with an argument less than or equal to zero 1928 ** turns off all busy handlers. 1929 ** 1930 ** ^(There can only be a single busy handler for a particular 1931 ** [database connection] any any given moment. If another busy handler 1932 ** was defined (using [sqlite3_busy_handler()]) prior to calling 1933 ** this routine, that other busy handler is cleared.)^ 1934 */ 1935 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms); 1936 1937 /* 1938 ** CAPI3REF: Convenience Routines For Running Queries 1939 ** 1940 ** This is a legacy interface that is preserved for backwards compatibility. 1941 ** Use of this interface is not recommended. 1942 ** 1943 ** Definition: A <b>result table</b> is memory data structure created by the 1944 ** [sqlite3_get_table()] interface. A result table records the 1945 ** complete query results from one or more queries. 1946 ** 1947 ** The table conceptually has a number of rows and columns. But 1948 ** these numbers are not part of the result table itself. These 1949 ** numbers are obtained separately. Let N be the number of rows 1950 ** and M be the number of columns. 1951 ** 1952 ** A result table is an array of pointers to zero-terminated UTF-8 strings. 1953 ** There are (N+1)*M elements in the array. The first M pointers point 1954 ** to zero-terminated strings that contain the names of the columns. 1955 ** The remaining entries all point to query results. NULL values result 1956 ** in NULL pointers. All other values are in their UTF-8 zero-terminated 1957 ** string representation as returned by [sqlite3_column_text()]. 1958 ** 1959 ** A result table might consist of one or more memory allocations. 1960 ** It is not safe to pass a result table directly to [sqlite3_free()]. 1961 ** A result table should be deallocated using [sqlite3_free_table()]. 1962 ** 1963 ** ^(As an example of the result table format, suppose a query result 1964 ** is as follows: 1965 ** 1966 ** <blockquote><pre> 1967 ** Name | Age 1968 ** ----------------------- 1969 ** Alice | 43 1970 ** Bob | 28 1971 ** Cindy | 21 1972 ** </pre></blockquote> 1973 ** 1974 ** There are two column (M==2) and three rows (N==3). Thus the 1975 ** result table has 8 entries. Suppose the result table is stored 1976 ** in an array names azResult. Then azResult holds this content: 1977 ** 1978 ** <blockquote><pre> 1979 ** azResult[0] = "Name"; 1980 ** azResult[1] = "Age"; 1981 ** azResult[2] = "Alice"; 1982 ** azResult[3] = "43"; 1983 ** azResult[4] = "Bob"; 1984 ** azResult[5] = "28"; 1985 ** azResult[6] = "Cindy"; 1986 ** azResult[7] = "21"; 1987 ** </pre></blockquote>)^ 1988 ** 1989 ** ^The sqlite3_get_table() function evaluates one or more 1990 ** semicolon-separated SQL statements in the zero-terminated UTF-8 1991 ** string of its 2nd parameter and returns a result table to the 1992 ** pointer given in its 3rd parameter. 1993 ** 1994 ** After the application has finished with the result from sqlite3_get_table(), 1995 ** it must pass the result table pointer to sqlite3_free_table() in order to 1996 ** release the memory that was malloced. Because of the way the 1997 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1998 ** function must not try to call [sqlite3_free()] directly. Only 1999 ** [sqlite3_free_table()] is able to release the memory properly and safely. 2000 ** 2001 ** The sqlite3_get_table() interface is implemented as a wrapper around 2002 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2003 ** to any internal data structures of SQLite. It uses only the public 2004 ** interface defined here. As a consequence, errors that occur in the 2005 ** wrapper layer outside of the internal [sqlite3_exec()] call are not 2006 ** reflected in subsequent calls to [sqlite3_errcode()] or 2007 ** [sqlite3_errmsg()]. 2008 */ 2009 SQLITE_API int sqlite3_get_table( 2010 sqlite3 *db, /* An open database */ 2011 const char *zSql, /* SQL to be evaluated */ 2012 char ***pazResult, /* Results of the query */ 2013 int *pnRow, /* Number of result rows written here */ 2014 int *pnColumn, /* Number of result columns written here */ 2015 char **pzErrmsg /* Error msg written here */ 2016 ); 2017 SQLITE_API void sqlite3_free_table(char **result); 2018 2019 /* 2020 ** CAPI3REF: Formatted String Printing Functions 2021 ** 2022 ** These routines are work-alikes of the "printf()" family of functions 2023 ** from the standard C library. 2024 ** 2025 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2026 ** results into memory obtained from [sqlite3_malloc()]. 2027 ** The strings returned by these two routines should be 2028 ** released by [sqlite3_free()]. ^Both routines return a 2029 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2030 ** memory to hold the resulting string. 2031 ** 2032 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2033 ** the standard C library. The result is written into the 2034 ** buffer supplied as the second parameter whose size is given by 2035 ** the first parameter. Note that the order of the 2036 ** first two parameters is reversed from snprintf().)^ This is an 2037 ** historical accident that cannot be fixed without breaking 2038 ** backwards compatibility. ^(Note also that sqlite3_snprintf() 2039 ** returns a pointer to its buffer instead of the number of 2040 ** characters actually written into the buffer.)^ We admit that 2041 ** the number of characters written would be a more useful return 2042 ** value but we cannot change the implementation of sqlite3_snprintf() 2043 ** now without breaking compatibility. 2044 ** 2045 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2046 ** guarantees that the buffer is always zero-terminated. ^The first 2047 ** parameter "n" is the total size of the buffer, including space for 2048 ** the zero terminator. So the longest string that can be completely 2049 ** written will be n-1 characters. 2050 ** 2051 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2052 ** 2053 ** These routines all implement some additional formatting 2054 ** options that are useful for constructing SQL statements. 2055 ** All of the usual printf() formatting options apply. In addition, there 2056 ** is are "%q", "%Q", and "%z" options. 2057 ** 2058 ** ^(The %q option works like %s in that it substitutes a nul-terminated 2059 ** string from the argument list. But %q also doubles every '\'' character. 2060 ** %q is designed for use inside a string literal.)^ By doubling each '\'' 2061 ** character it escapes that character and allows it to be inserted into 2062 ** the string. 2063 ** 2064 ** For example, assume the string variable zText contains text as follows: 2065 ** 2066 ** <blockquote><pre> 2067 ** char *zText = "It's a happy day!"; 2068 ** </pre></blockquote> 2069 ** 2070 ** One can use this text in an SQL statement as follows: 2071 ** 2072 ** <blockquote><pre> 2073 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2074 ** sqlite3_exec(db, zSQL, 0, 0, 0); 2075 ** sqlite3_free(zSQL); 2076 ** </pre></blockquote> 2077 ** 2078 ** Because the %q format string is used, the '\'' character in zText 2079 ** is escaped and the SQL generated is as follows: 2080 ** 2081 ** <blockquote><pre> 2082 ** INSERT INTO table1 VALUES('It''s a happy day!') 2083 ** </pre></blockquote> 2084 ** 2085 ** This is correct. Had we used %s instead of %q, the generated SQL 2086 ** would have looked like this: 2087 ** 2088 ** <blockquote><pre> 2089 ** INSERT INTO table1 VALUES('It's a happy day!'); 2090 ** </pre></blockquote> 2091 ** 2092 ** This second example is an SQL syntax error. As a general rule you should 2093 ** always use %q instead of %s when inserting text into a string literal. 2094 ** 2095 ** ^(The %Q option works like %q except it also adds single quotes around 2096 ** the outside of the total string. Additionally, if the parameter in the 2097 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2098 ** single quotes).)^ So, for example, one could say: 2099 ** 2100 ** <blockquote><pre> 2101 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2102 ** sqlite3_exec(db, zSQL, 0, 0, 0); 2103 ** sqlite3_free(zSQL); 2104 ** </pre></blockquote> 2105 ** 2106 ** The code above will render a correct SQL statement in the zSQL 2107 ** variable even if the zText variable is a NULL pointer. 2108 ** 2109 ** ^(The "%z" formatting option works like "%s" but with the 2110 ** addition that after the string has been read and copied into 2111 ** the result, [sqlite3_free()] is called on the input string.)^ 2112 */ 2113 SQLITE_API char *sqlite3_mprintf(const char*,...); 2114 SQLITE_API char *sqlite3_vmprintf(const char*, va_list); 2115 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...); 2116 SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2117 2118 /* 2119 ** CAPI3REF: Memory Allocation Subsystem 2120 ** 2121 ** The SQLite core uses these three routines for all of its own 2122 ** internal memory allocation needs. "Core" in the previous sentence 2123 ** does not include operating-system specific VFS implementation. The 2124 ** Windows VFS uses native malloc() and free() for some operations. 2125 ** 2126 ** ^The sqlite3_malloc() routine returns a pointer to a block 2127 ** of memory at least N bytes in length, where N is the parameter. 2128 ** ^If sqlite3_malloc() is unable to obtain sufficient free 2129 ** memory, it returns a NULL pointer. ^If the parameter N to 2130 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2131 ** a NULL pointer. 2132 ** 2133 ** ^Calling sqlite3_free() with a pointer previously returned 2134 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2135 ** that it might be reused. ^The sqlite3_free() routine is 2136 ** a no-op if is called with a NULL pointer. Passing a NULL pointer 2137 ** to sqlite3_free() is harmless. After being freed, memory 2138 ** should neither be read nor written. Even reading previously freed 2139 ** memory might result in a segmentation fault or other severe error. 2140 ** Memory corruption, a segmentation fault, or other severe error 2141 ** might result if sqlite3_free() is called with a non-NULL pointer that 2142 ** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2143 ** 2144 ** ^(The sqlite3_realloc() interface attempts to resize a 2145 ** prior memory allocation to be at least N bytes, where N is the 2146 ** second parameter. The memory allocation to be resized is the first 2147 ** parameter.)^ ^ If the first parameter to sqlite3_realloc() 2148 ** is a NULL pointer then its behavior is identical to calling 2149 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 2150 ** ^If the second parameter to sqlite3_realloc() is zero or 2151 ** negative then the behavior is exactly the same as calling 2152 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 2153 ** ^sqlite3_realloc() returns a pointer to a memory allocation 2154 ** of at least N bytes in size or NULL if sufficient memory is unavailable. 2155 ** ^If M is the size of the prior allocation, then min(N,M) bytes 2156 ** of the prior allocation are copied into the beginning of buffer returned 2157 ** by sqlite3_realloc() and the prior allocation is freed. 2158 ** ^If sqlite3_realloc() returns NULL, then the prior allocation 2159 ** is not freed. 2160 ** 2161 ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 2162 ** is always aligned to at least an 8 byte boundary, or to a 2163 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2164 ** option is used. 2165 ** 2166 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2167 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2168 ** implementation of these routines to be omitted. That capability 2169 ** is no longer provided. Only built-in memory allocators can be used. 2170 ** 2171 ** The Windows OS interface layer calls 2172 ** the system malloc() and free() directly when converting 2173 ** filenames between the UTF-8 encoding used by SQLite 2174 ** and whatever filename encoding is used by the particular Windows 2175 ** installation. Memory allocation errors are detected, but 2176 ** they are reported back as [SQLITE_CANTOPEN] or 2177 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2178 ** 2179 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2180 ** must be either NULL or else pointers obtained from a prior 2181 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2182 ** not yet been released. 2183 ** 2184 ** The application must not read or write any part of 2185 ** a block of memory after it has been released using 2186 ** [sqlite3_free()] or [sqlite3_realloc()]. 2187 */ 2188 SQLITE_API void *sqlite3_malloc(int); 2189 SQLITE_API void *sqlite3_realloc(void*, int); 2190 SQLITE_API void sqlite3_free(void*); 2191 2192 /* 2193 ** CAPI3REF: Memory Allocator Statistics 2194 ** 2195 ** SQLite provides these two interfaces for reporting on the status 2196 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2197 ** routines, which form the built-in memory allocation subsystem. 2198 ** 2199 ** ^The [sqlite3_memory_used()] routine returns the number of bytes 2200 ** of memory currently outstanding (malloced but not freed). 2201 ** ^The [sqlite3_memory_highwater()] routine returns the maximum 2202 ** value of [sqlite3_memory_used()] since the high-water mark 2203 ** was last reset. ^The values returned by [sqlite3_memory_used()] and 2204 ** [sqlite3_memory_highwater()] include any overhead 2205 ** added by SQLite in its implementation of [sqlite3_malloc()], 2206 ** but not overhead added by the any underlying system library 2207 ** routines that [sqlite3_malloc()] may call. 2208 ** 2209 ** ^The memory high-water mark is reset to the current value of 2210 ** [sqlite3_memory_used()] if and only if the parameter to 2211 ** [sqlite3_memory_highwater()] is true. ^The value returned 2212 ** by [sqlite3_memory_highwater(1)] is the high-water mark 2213 ** prior to the reset. 2214 */ 2215 SQLITE_API sqlite3_int64 sqlite3_memory_used(void); 2216 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2217 2218 /* 2219 ** CAPI3REF: Pseudo-Random Number Generator 2220 ** 2221 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2222 ** select random [ROWID | ROWIDs] when inserting new records into a table that 2223 ** already uses the largest possible [ROWID]. The PRNG is also used for 2224 ** the build-in random() and randomblob() SQL functions. This interface allows 2225 ** applications to access the same PRNG for other purposes. 2226 ** 2227 ** ^A call to this routine stores N bytes of randomness into buffer P. 2228 ** 2229 ** ^The first time this routine is invoked (either internally or by 2230 ** the application) the PRNG is seeded using randomness obtained 2231 ** from the xRandomness method of the default [sqlite3_vfs] object. 2232 ** ^On all subsequent invocations, the pseudo-randomness is generated 2233 ** internally and without recourse to the [sqlite3_vfs] xRandomness 2234 ** method. 2235 */ 2236 SQLITE_API void sqlite3_randomness(int N, void *P); 2237 2238 /* 2239 ** CAPI3REF: Compile-Time Authorization Callbacks 2240 ** 2241 ** ^This routine registers an authorizer callback with a particular 2242 ** [database connection], supplied in the first argument. 2243 ** ^The authorizer callback is invoked as SQL statements are being compiled 2244 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2245 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2246 ** points during the compilation process, as logic is being created 2247 ** to perform various actions, the authorizer callback is invoked to 2248 ** see if those actions are allowed. ^The authorizer callback should 2249 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2250 ** specific action but allow the SQL statement to continue to be 2251 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2252 ** rejected with an error. ^If the authorizer callback returns 2253 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2254 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2255 ** the authorizer will fail with an error message. 2256 ** 2257 ** When the callback returns [SQLITE_OK], that means the operation 2258 ** requested is ok. ^When the callback returns [SQLITE_DENY], the 2259 ** [sqlite3_prepare_v2()] or equivalent call that triggered the 2260 ** authorizer will fail with an error message explaining that 2261 ** access is denied. 2262 ** 2263 ** ^The first parameter to the authorizer callback is a copy of the third 2264 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2265 ** to the callback is an integer [SQLITE_COPY | action code] that specifies 2266 ** the particular action to be authorized. ^The third through sixth parameters 2267 ** to the callback are zero-terminated strings that contain additional 2268 ** details about the action to be authorized. 2269 ** 2270 ** ^If the action code is [SQLITE_READ] 2271 ** and the callback returns [SQLITE_IGNORE] then the 2272 ** [prepared statement] statement is constructed to substitute 2273 ** a NULL value in place of the table column that would have 2274 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2275 ** return can be used to deny an untrusted user access to individual 2276 ** columns of a table. 2277 ** ^If the action code is [SQLITE_DELETE] and the callback returns 2278 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2279 ** [truncate optimization] is disabled and all rows are deleted individually. 2280 ** 2281 ** An authorizer is used when [sqlite3_prepare | preparing] 2282 ** SQL statements from an untrusted source, to ensure that the SQL statements 2283 ** do not try to access data they are not allowed to see, or that they do not 2284 ** try to execute malicious statements that damage the database. For 2285 ** example, an application may allow a user to enter arbitrary 2286 ** SQL queries for evaluation by a database. But the application does 2287 ** not want the user to be able to make arbitrary changes to the 2288 ** database. An authorizer could then be put in place while the 2289 ** user-entered SQL is being [sqlite3_prepare | prepared] that 2290 ** disallows everything except [SELECT] statements. 2291 ** 2292 ** Applications that need to process SQL from untrusted sources 2293 ** might also consider lowering resource limits using [sqlite3_limit()] 2294 ** and limiting database size using the [max_page_count] [PRAGMA] 2295 ** in addition to using an authorizer. 2296 ** 2297 ** ^(Only a single authorizer can be in place on a database connection 2298 ** at a time. Each call to sqlite3_set_authorizer overrides the 2299 ** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2300 ** The authorizer is disabled by default. 2301 ** 2302 ** The authorizer callback must not do anything that will modify 2303 ** the database connection that invoked the authorizer callback. 2304 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2305 ** database connections for the meaning of "modify" in this paragraph. 2306 ** 2307 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2308 ** statement might be re-prepared during [sqlite3_step()] due to a 2309 ** schema change. Hence, the application should ensure that the 2310 ** correct authorizer callback remains in place during the [sqlite3_step()]. 2311 ** 2312 ** ^Note that the authorizer callback is invoked only during 2313 ** [sqlite3_prepare()] or its variants. Authorization is not 2314 ** performed during statement evaluation in [sqlite3_step()], unless 2315 ** as stated in the previous paragraph, sqlite3_step() invokes 2316 ** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2317 */ 2318 SQLITE_API int sqlite3_set_authorizer( 2319 sqlite3*, 2320 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2321 void *pUserData 2322 ); 2323 2324 /* 2325 ** CAPI3REF: Authorizer Return Codes 2326 ** 2327 ** The [sqlite3_set_authorizer | authorizer callback function] must 2328 ** return either [SQLITE_OK] or one of these two constants in order 2329 ** to signal SQLite whether or not the action is permitted. See the 2330 ** [sqlite3_set_authorizer | authorizer documentation] for additional 2331 ** information. 2332 ** 2333 ** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code] 2334 ** from the [sqlite3_vtab_on_conflict()] interface. 2335 */ 2336 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2337 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2338 2339 /* 2340 ** CAPI3REF: Authorizer Action Codes 2341 ** 2342 ** The [sqlite3_set_authorizer()] interface registers a callback function 2343 ** that is invoked to authorize certain SQL statement actions. The 2344 ** second parameter to the callback is an integer code that specifies 2345 ** what action is being authorized. These are the integer action codes that 2346 ** the authorizer callback may be passed. 2347 ** 2348 ** These action code values signify what kind of operation is to be 2349 ** authorized. The 3rd and 4th parameters to the authorization 2350 ** callback function will be parameters or NULL depending on which of these 2351 ** codes is used as the second parameter. ^(The 5th parameter to the 2352 ** authorizer callback is the name of the database ("main", "temp", 2353 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2354 ** is the name of the inner-most trigger or view that is responsible for 2355 ** the access attempt or NULL if this access attempt is directly from 2356 ** top-level SQL code. 2357 */ 2358 /******************************************* 3rd ************ 4th ***********/ 2359 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2360 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2361 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2362 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2363 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2364 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2365 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2366 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2367 #define SQLITE_DELETE 9 /* Table Name NULL */ 2368 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2369 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2370 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2371 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2372 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2373 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2374 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2375 #define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2376 #define SQLITE_INSERT 18 /* Table Name NULL */ 2377 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2378 #define SQLITE_READ 20 /* Table Name Column Name */ 2379 #define SQLITE_SELECT 21 /* NULL NULL */ 2380 #define SQLITE_TRANSACTION 22 /* Operation NULL */ 2381 #define SQLITE_UPDATE 23 /* Table Name Column Name */ 2382 #define SQLITE_ATTACH 24 /* Filename NULL */ 2383 #define SQLITE_DETACH 25 /* Database Name NULL */ 2384 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2385 #define SQLITE_REINDEX 27 /* Index Name NULL */ 2386 #define SQLITE_ANALYZE 28 /* Table Name NULL */ 2387 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2388 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2389 #define SQLITE_FUNCTION 31 /* NULL Function Name */ 2390 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2391 #define SQLITE_COPY 0 /* No longer used */ 2392 2393 /* 2394 ** CAPI3REF: Tracing And Profiling Functions 2395 ** 2396 ** These routines register callback functions that can be used for 2397 ** tracing and profiling the execution of SQL statements. 2398 ** 2399 ** ^The callback function registered by sqlite3_trace() is invoked at 2400 ** various times when an SQL statement is being run by [sqlite3_step()]. 2401 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2402 ** SQL statement text as the statement first begins executing. 2403 ** ^(Additional sqlite3_trace() callbacks might occur 2404 ** as each triggered subprogram is entered. The callbacks for triggers 2405 ** contain a UTF-8 SQL comment that identifies the trigger.)^ 2406 ** 2407 ** ^The callback function registered by sqlite3_profile() is invoked 2408 ** as each SQL statement finishes. ^The profile callback contains 2409 ** the original statement text and an estimate of wall-clock time 2410 ** of how long that statement took to run. ^The profile callback 2411 ** time is in units of nanoseconds, however the current implementation 2412 ** is only capable of millisecond resolution so the six least significant 2413 ** digits in the time are meaningless. Future versions of SQLite 2414 ** might provide greater resolution on the profiler callback. The 2415 ** sqlite3_profile() function is considered experimental and is 2416 ** subject to change in future versions of SQLite. 2417 */ 2418 SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2419 SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2420 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2421 2422 /* 2423 ** CAPI3REF: Query Progress Callbacks 2424 ** 2425 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2426 ** function X to be invoked periodically during long running calls to 2427 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2428 ** database connection D. An example use for this 2429 ** interface is to keep a GUI updated during a large query. 2430 ** 2431 ** ^The parameter P is passed through as the only parameter to the 2432 ** callback function X. ^The parameter N is the number of 2433 ** [virtual machine instructions] that are evaluated between successive 2434 ** invocations of the callback X. 2435 ** 2436 ** ^Only a single progress handler may be defined at one time per 2437 ** [database connection]; setting a new progress handler cancels the 2438 ** old one. ^Setting parameter X to NULL disables the progress handler. 2439 ** ^The progress handler is also disabled by setting N to a value less 2440 ** than 1. 2441 ** 2442 ** ^If the progress callback returns non-zero, the operation is 2443 ** interrupted. This feature can be used to implement a 2444 ** "Cancel" button on a GUI progress dialog box. 2445 ** 2446 ** The progress handler callback must not do anything that will modify 2447 ** the database connection that invoked the progress handler. 2448 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2449 ** database connections for the meaning of "modify" in this paragraph. 2450 ** 2451 */ 2452 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2453 2454 /* 2455 ** CAPI3REF: Opening A New Database Connection 2456 ** 2457 ** ^These routines open an SQLite database file as specified by the 2458 ** filename argument. ^The filename argument is interpreted as UTF-8 for 2459 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2460 ** order for sqlite3_open16(). ^(A [database connection] handle is usually 2461 ** returned in *ppDb, even if an error occurs. The only exception is that 2462 ** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2463 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2464 ** object.)^ ^(If the database is opened (and/or created) successfully, then 2465 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2466 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2467 ** an English language description of the error following a failure of any 2468 ** of the sqlite3_open() routines. 2469 ** 2470 ** ^The default encoding for the database will be UTF-8 if 2471 ** sqlite3_open() or sqlite3_open_v2() is called and 2472 ** UTF-16 in the native byte order if sqlite3_open16() is used. 2473 ** 2474 ** Whether or not an error occurs when it is opened, resources 2475 ** associated with the [database connection] handle should be released by 2476 ** passing it to [sqlite3_close()] when it is no longer required. 2477 ** 2478 ** The sqlite3_open_v2() interface works like sqlite3_open() 2479 ** except that it accepts two additional parameters for additional control 2480 ** over the new database connection. ^(The flags parameter to 2481 ** sqlite3_open_v2() can take one of 2482 ** the following three values, optionally combined with the 2483 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2484 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2485 ** 2486 ** <dl> 2487 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2488 ** <dd>The database is opened in read-only mode. If the database does not 2489 ** already exist, an error is returned.</dd>)^ 2490 ** 2491 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2492 ** <dd>The database is opened for reading and writing if possible, or reading 2493 ** only if the file is write protected by the operating system. In either 2494 ** case the database must already exist, otherwise an error is returned.</dd>)^ 2495 ** 2496 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2497 ** <dd>The database is opened for reading and writing, and is created if 2498 ** it does not already exist. This is the behavior that is always used for 2499 ** sqlite3_open() and sqlite3_open16().</dd>)^ 2500 ** </dl> 2501 ** 2502 ** If the 3rd parameter to sqlite3_open_v2() is not one of the 2503 ** combinations shown above optionally combined with other 2504 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2505 ** then the behavior is undefined. 2506 ** 2507 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2508 ** opens in the multi-thread [threading mode] as long as the single-thread 2509 ** mode has not been set at compile-time or start-time. ^If the 2510 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2511 ** in the serialized [threading mode] unless single-thread was 2512 ** previously selected at compile-time or start-time. 2513 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2514 ** eligible to use [shared cache mode], regardless of whether or not shared 2515 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2516 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2517 ** participate in [shared cache mode] even if it is enabled. 2518 ** 2519 ** ^The fourth parameter to sqlite3_open_v2() is the name of the 2520 ** [sqlite3_vfs] object that defines the operating system interface that 2521 ** the new database connection should use. ^If the fourth parameter is 2522 ** a NULL pointer then the default [sqlite3_vfs] object is used. 2523 ** 2524 ** ^If the filename is ":memory:", then a private, temporary in-memory database 2525 ** is created for the connection. ^This in-memory database will vanish when 2526 ** the database connection is closed. Future versions of SQLite might 2527 ** make use of additional special filenames that begin with the ":" character. 2528 ** It is recommended that when a database filename actually does begin with 2529 ** a ":" character you should prefix the filename with a pathname such as 2530 ** "./" to avoid ambiguity. 2531 ** 2532 ** ^If the filename is an empty string, then a private, temporary 2533 ** on-disk database will be created. ^This private database will be 2534 ** automatically deleted as soon as the database connection is closed. 2535 ** 2536 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2537 ** 2538 ** ^If [URI filename] interpretation is enabled, and the filename argument 2539 ** begins with "file:", then the filename is interpreted as a URI. ^URI 2540 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2541 ** set in the fourth argument to sqlite3_open_v2(), or if it has 2542 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2543 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2544 ** As of SQLite version 3.7.7, URI filename interpretation is turned off 2545 ** by default, but future releases of SQLite might enable URI filename 2546 ** interpretation by default. See "[URI filenames]" for additional 2547 ** information. 2548 ** 2549 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2550 ** authority, then it must be either an empty string or the string 2551 ** "localhost". ^If the authority is not an empty string or "localhost", an 2552 ** error is returned to the caller. ^The fragment component of a URI, if 2553 ** present, is ignored. 2554 ** 2555 ** ^SQLite uses the path component of the URI as the name of the disk file 2556 ** which contains the database. ^If the path begins with a '/' character, 2557 ** then it is interpreted as an absolute path. ^If the path does not begin 2558 ** with a '/' (meaning that the authority section is omitted from the URI) 2559 ** then the path is interpreted as a relative path. 2560 ** ^On windows, the first component of an absolute path 2561 ** is a drive specification (e.g. "C:"). 2562 ** 2563 ** [[core URI query parameters]] 2564 ** The query component of a URI may contain parameters that are interpreted 2565 ** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2566 ** SQLite interprets the following three query parameters: 2567 ** 2568 ** <ul> 2569 ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2570 ** a VFS object that provides the operating system interface that should 2571 ** be used to access the database file on disk. ^If this option is set to 2572 ** an empty string the default VFS object is used. ^Specifying an unknown 2573 ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2574 ** present, then the VFS specified by the option takes precedence over 2575 ** the value passed as the fourth parameter to sqlite3_open_v2(). 2576 ** 2577 ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw" or 2578 ** "rwc". Attempting to set it to any other value is an error)^. 2579 ** ^If "ro" is specified, then the database is opened for read-only 2580 ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2581 ** third argument to sqlite3_prepare_v2(). ^If the mode option is set to 2582 ** "rw", then the database is opened for read-write (but not create) 2583 ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2584 ** been set. ^Value "rwc" is equivalent to setting both 2585 ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If sqlite3_open_v2() is 2586 ** used, it is an error to specify a value for the mode parameter that is 2587 ** less restrictive than that specified by the flags passed as the third 2588 ** parameter. 2589 ** 2590 ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2591 ** "private". ^Setting it to "shared" is equivalent to setting the 2592 ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2593 ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2594 ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2595 ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2596 ** a URI filename, its value overrides any behaviour requested by setting 2597 ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2598 ** </ul> 2599 ** 2600 ** ^Specifying an unknown parameter in the query component of a URI is not an 2601 ** error. Future versions of SQLite might understand additional query 2602 ** parameters. See "[query parameters with special meaning to SQLite]" for 2603 ** additional information. 2604 ** 2605 ** [[URI filename examples]] <h3>URI filename examples</h3> 2606 ** 2607 ** <table border="1" align=center cellpadding=5> 2608 ** <tr><th> URI filenames <th> Results 2609 ** <tr><td> file:data.db <td> 2610 ** Open the file "data.db" in the current directory. 2611 ** <tr><td> file:/home/fred/data.db<br> 2612 ** file:///home/fred/data.db <br> 2613 ** file://localhost/home/fred/data.db <br> <td> 2614 ** Open the database file "/home/fred/data.db". 2615 ** <tr><td> file://darkstar/home/fred/data.db <td> 2616 ** An error. "darkstar" is not a recognized authority. 2617 ** <tr><td style="white-space:nowrap"> 2618 ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2619 ** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2620 ** C:. Note that the %20 escaping in this example is not strictly 2621 ** necessary - space characters can be used literally 2622 ** in URI filenames. 2623 ** <tr><td> file:data.db?mode=ro&cache=private <td> 2624 ** Open file "data.db" in the current directory for read-only access. 2625 ** Regardless of whether or not shared-cache mode is enabled by 2626 ** default, use a private cache. 2627 ** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td> 2628 ** Open file "/home/fred/data.db". Use the special VFS "unix-nolock". 2629 ** <tr><td> file:data.db?mode=readonly <td> 2630 ** An error. "readonly" is not a valid option for the "mode" parameter. 2631 ** </table> 2632 ** 2633 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2634 ** query components of a URI. A hexadecimal escape sequence consists of a 2635 ** percent sign - "%" - followed by exactly two hexadecimal digits 2636 ** specifying an octet value. ^Before the path or query components of a 2637 ** URI filename are interpreted, they are encoded using UTF-8 and all 2638 ** hexadecimal escape sequences replaced by a single byte containing the 2639 ** corresponding octet. If this process generates an invalid UTF-8 encoding, 2640 ** the results are undefined. 2641 ** 2642 ** <b>Note to Windows users:</b> The encoding used for the filename argument 2643 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2644 ** codepage is currently defined. Filenames containing international 2645 ** characters must be converted to UTF-8 prior to passing them into 2646 ** sqlite3_open() or sqlite3_open_v2(). 2647 */ 2648 SQLITE_API int sqlite3_open( 2649 const char *filename, /* Database filename (UTF-8) */ 2650 sqlite3 **ppDb /* OUT: SQLite db handle */ 2651 ); 2652 SQLITE_API int sqlite3_open16( 2653 const void *filename, /* Database filename (UTF-16) */ 2654 sqlite3 **ppDb /* OUT: SQLite db handle */ 2655 ); 2656 SQLITE_API int sqlite3_open_v2( 2657 const char *filename, /* Database filename (UTF-8) */ 2658 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2659 int flags, /* Flags */ 2660 const char *zVfs /* Name of VFS module to use */ 2661 ); 2662 2663 /* 2664 ** CAPI3REF: Obtain Values For URI Parameters 2665 ** 2666 ** These are utility routines, useful to VFS implementations, that check 2667 ** to see if a database file was a URI that contained a specific query 2668 ** parameter, and if so obtains the value of that query parameter. 2669 ** 2670 ** If F is the database filename pointer passed into the xOpen() method of 2671 ** a VFS implementation when the flags parameter to xOpen() has one or 2672 ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 2673 ** P is the name of the query parameter, then 2674 ** sqlite3_uri_parameter(F,P) returns the value of the P 2675 ** parameter if it exists or a NULL pointer if P does not appear as a 2676 ** query parameter on F. If P is a query parameter of F 2677 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns 2678 ** a pointer to an empty string. 2679 ** 2680 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 2681 ** parameter and returns true (1) or false (0) according to the value 2682 ** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 2683 ** value of query parameter P is one of "yes", "true", or "on" in any 2684 ** case or if the value begins with a non-zero number. The 2685 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 2686 ** query parameter P is one of "no", "false", or "off" in any case or 2687 ** if the value begins with a numeric zero. If P is not a query 2688 ** parameter on F or if the value of P is does not match any of the 2689 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 2690 ** 2691 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 2692 ** 64-bit signed integer and returns that integer, or D if P does not 2693 ** exist. If the value of P is something other than an integer, then 2694 ** zero is returned. 2695 ** 2696 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 2697 ** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 2698 ** is not a database file pathname pointer that SQLite passed into the xOpen 2699 ** VFS method, then the behavior of this routine is undefined and probably 2700 ** undesirable. 2701 */ 2702 SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 2703 SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 2704 SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 2705 2706 2707 /* 2708 ** CAPI3REF: Error Codes And Messages 2709 ** 2710 ** ^The sqlite3_errcode() interface returns the numeric [result code] or 2711 ** [extended result code] for the most recent failed sqlite3_* API call 2712 ** associated with a [database connection]. If a prior API call failed 2713 ** but the most recent API call succeeded, the return value from 2714 ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2715 ** interface is the same except that it always returns the 2716 ** [extended result code] even when extended result codes are 2717 ** disabled. 2718 ** 2719 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2720 ** text that describes the error, as either UTF-8 or UTF-16 respectively. 2721 ** ^(Memory to hold the error message string is managed internally. 2722 ** The application does not need to worry about freeing the result. 2723 ** However, the error string might be overwritten or deallocated by 2724 ** subsequent calls to other SQLite interface functions.)^ 2725 ** 2726 ** When the serialized [threading mode] is in use, it might be the 2727 ** case that a second error occurs on a separate thread in between 2728 ** the time of the first error and the call to these interfaces. 2729 ** When that happens, the second error will be reported since these 2730 ** interfaces always report the most recent result. To avoid 2731 ** this, each thread can obtain exclusive use of the [database connection] D 2732 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2733 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2734 ** all calls to the interfaces listed here are completed. 2735 ** 2736 ** If an interface fails with SQLITE_MISUSE, that means the interface 2737 ** was invoked incorrectly by the application. In that case, the 2738 ** error code and message may or may not be set. 2739 */ 2740 SQLITE_API int sqlite3_errcode(sqlite3 *db); 2741 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db); 2742 SQLITE_API const char *sqlite3_errmsg(sqlite3*); 2743 SQLITE_API const void *sqlite3_errmsg16(sqlite3*); 2744 2745 /* 2746 ** CAPI3REF: SQL Statement Object 2747 ** KEYWORDS: {prepared statement} {prepared statements} 2748 ** 2749 ** An instance of this object represents a single SQL statement. 2750 ** This object is variously known as a "prepared statement" or a 2751 ** "compiled SQL statement" or simply as a "statement". 2752 ** 2753 ** The life of a statement object goes something like this: 2754 ** 2755 ** <ol> 2756 ** <li> Create the object using [sqlite3_prepare_v2()] or a related 2757 ** function. 2758 ** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2759 ** interfaces. 2760 ** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2761 ** <li> Reset the statement using [sqlite3_reset()] then go back 2762 ** to step 2. Do this zero or more times. 2763 ** <li> Destroy the object using [sqlite3_finalize()]. 2764 ** </ol> 2765 ** 2766 ** Refer to documentation on individual methods above for additional 2767 ** information. 2768 */ 2769 typedef struct sqlite3_stmt sqlite3_stmt; 2770 2771 /* 2772 ** CAPI3REF: Run-time Limits 2773 ** 2774 ** ^(This interface allows the size of various constructs to be limited 2775 ** on a connection by connection basis. The first parameter is the 2776 ** [database connection] whose limit is to be set or queried. The 2777 ** second parameter is one of the [limit categories] that define a 2778 ** class of constructs to be size limited. The third parameter is the 2779 ** new limit for that construct.)^ 2780 ** 2781 ** ^If the new limit is a negative number, the limit is unchanged. 2782 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 2783 ** [limits | hard upper bound] 2784 ** set at compile-time by a C preprocessor macro called 2785 ** [limits | SQLITE_MAX_<i>NAME</i>]. 2786 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2787 ** ^Attempts to increase a limit above its hard upper bound are 2788 ** silently truncated to the hard upper bound. 2789 ** 2790 ** ^Regardless of whether or not the limit was changed, the 2791 ** [sqlite3_limit()] interface returns the prior value of the limit. 2792 ** ^Hence, to find the current value of a limit without changing it, 2793 ** simply invoke this interface with the third parameter set to -1. 2794 ** 2795 ** Run-time limits are intended for use in applications that manage 2796 ** both their own internal database and also databases that are controlled 2797 ** by untrusted external sources. An example application might be a 2798 ** web browser that has its own databases for storing history and 2799 ** separate databases controlled by JavaScript applications downloaded 2800 ** off the Internet. The internal databases can be given the 2801 ** large, default limits. Databases managed by external sources can 2802 ** be given much smaller limits designed to prevent a denial of service 2803 ** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2804 ** interface to further control untrusted SQL. The size of the database 2805 ** created by an untrusted script can be contained using the 2806 ** [max_page_count] [PRAGMA]. 2807 ** 2808 ** New run-time limit categories may be added in future releases. 2809 */ 2810 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal); 2811 2812 /* 2813 ** CAPI3REF: Run-Time Limit Categories 2814 ** KEYWORDS: {limit category} {*limit categories} 2815 ** 2816 ** These constants define various performance limits 2817 ** that can be lowered at run-time using [sqlite3_limit()]. 2818 ** The synopsis of the meanings of the various limits is shown below. 2819 ** Additional information is available at [limits | Limits in SQLite]. 2820 ** 2821 ** <dl> 2822 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2823 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 2824 ** 2825 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2826 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2827 ** 2828 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2829 ** <dd>The maximum number of columns in a table definition or in the 2830 ** result set of a [SELECT] or the maximum number of columns in an index 2831 ** or in an ORDER BY or GROUP BY clause.</dd>)^ 2832 ** 2833 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2834 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2835 ** 2836 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2837 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2838 ** 2839 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2840 ** <dd>The maximum number of instructions in a virtual machine program 2841 ** used to implement an SQL statement. This limit is not currently 2842 ** enforced, though that might be added in some future release of 2843 ** SQLite.</dd>)^ 2844 ** 2845 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2846 ** <dd>The maximum number of arguments on a function.</dd>)^ 2847 ** 2848 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2849 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2850 ** 2851 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 2852 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2853 ** <dd>The maximum length of the pattern argument to the [LIKE] or 2854 ** [GLOB] operators.</dd>)^ 2855 ** 2856 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 2857 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2858 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 2859 ** 2860 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2861 ** <dd>The maximum depth of recursion for triggers.</dd>)^ 2862 ** </dl> 2863 */ 2864 #define SQLITE_LIMIT_LENGTH 0 2865 #define SQLITE_LIMIT_SQL_LENGTH 1 2866 #define SQLITE_LIMIT_COLUMN 2 2867 #define SQLITE_LIMIT_EXPR_DEPTH 3 2868 #define SQLITE_LIMIT_COMPOUND_SELECT 4 2869 #define SQLITE_LIMIT_VDBE_OP 5 2870 #define SQLITE_LIMIT_FUNCTION_ARG 6 2871 #define SQLITE_LIMIT_ATTACHED 7 2872 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2873 #define SQLITE_LIMIT_VARIABLE_NUMBER 9 2874 #define SQLITE_LIMIT_TRIGGER_DEPTH 10 2875 2876 /* 2877 ** CAPI3REF: Compiling An SQL Statement 2878 ** KEYWORDS: {SQL statement compiler} 2879 ** 2880 ** To execute an SQL query, it must first be compiled into a byte-code 2881 ** program using one of these routines. 2882 ** 2883 ** The first argument, "db", is a [database connection] obtained from a 2884 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2885 ** [sqlite3_open16()]. The database connection must not have been closed. 2886 ** 2887 ** The second argument, "zSql", is the statement to be compiled, encoded 2888 ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2889 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2890 ** use UTF-16. 2891 ** 2892 ** ^If the nByte argument is less than zero, then zSql is read up to the 2893 ** first zero terminator. ^If nByte is non-negative, then it is the maximum 2894 ** number of bytes read from zSql. ^When nByte is non-negative, the 2895 ** zSql string ends at either the first '\000' or '\u0000' character or 2896 ** the nByte-th byte, whichever comes first. If the caller knows 2897 ** that the supplied string is nul-terminated, then there is a small 2898 ** performance advantage to be gained by passing an nByte parameter that 2899 ** is equal to the number of bytes in the input string <i>including</i> 2900 ** the nul-terminator bytes as this saves SQLite from having to 2901 ** make a copy of the input string. 2902 ** 2903 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte 2904 ** past the end of the first SQL statement in zSql. These routines only 2905 ** compile the first statement in zSql, so *pzTail is left pointing to 2906 ** what remains uncompiled. 2907 ** 2908 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 2909 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 2910 ** to NULL. ^If the input text contains no SQL (if the input is an empty 2911 ** string or a comment) then *ppStmt is set to NULL. 2912 ** The calling procedure is responsible for deleting the compiled 2913 ** SQL statement using [sqlite3_finalize()] after it has finished with it. 2914 ** ppStmt may not be NULL. 2915 ** 2916 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 2917 ** otherwise an [error code] is returned. 2918 ** 2919 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2920 ** recommended for all new programs. The two older interfaces are retained 2921 ** for backwards compatibility, but their use is discouraged. 2922 ** ^In the "v2" interfaces, the prepared statement 2923 ** that is returned (the [sqlite3_stmt] object) contains a copy of the 2924 ** original SQL text. This causes the [sqlite3_step()] interface to 2925 ** behave differently in three ways: 2926 ** 2927 ** <ol> 2928 ** <li> 2929 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2930 ** always used to do, [sqlite3_step()] will automatically recompile the SQL 2931 ** statement and try to run it again. 2932 ** </li> 2933 ** 2934 ** <li> 2935 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed 2936 ** [error codes] or [extended error codes]. ^The legacy behavior was that 2937 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2938 ** and the application would have to make a second call to [sqlite3_reset()] 2939 ** in order to find the underlying cause of the problem. With the "v2" prepare 2940 ** interfaces, the underlying reason for the error is returned immediately. 2941 ** </li> 2942 ** 2943 ** <li> 2944 ** ^If the specific value bound to [parameter | host parameter] in the 2945 ** WHERE clause might influence the choice of query plan for a statement, 2946 ** then the statement will be automatically recompiled, as if there had been 2947 ** a schema change, on the first [sqlite3_step()] call following any change 2948 ** to the [sqlite3_bind_text | bindings] of that [parameter]. 2949 ** ^The specific value of WHERE-clause [parameter] might influence the 2950 ** choice of query plan if the parameter is the left-hand side of a [LIKE] 2951 ** or [GLOB] operator or if the parameter is compared to an indexed column 2952 ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 2953 ** the 2954 ** </li> 2955 ** </ol> 2956 */ 2957 SQLITE_API int sqlite3_prepare( 2958 sqlite3 *db, /* Database handle */ 2959 const char *zSql, /* SQL statement, UTF-8 encoded */ 2960 int nByte, /* Maximum length of zSql in bytes. */ 2961 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2962 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2963 ); 2964 SQLITE_API int sqlite3_prepare_v2( 2965 sqlite3 *db, /* Database handle */ 2966 const char *zSql, /* SQL statement, UTF-8 encoded */ 2967 int nByte, /* Maximum length of zSql in bytes. */ 2968 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2969 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2970 ); 2971 SQLITE_API int sqlite3_prepare16( 2972 sqlite3 *db, /* Database handle */ 2973 const void *zSql, /* SQL statement, UTF-16 encoded */ 2974 int nByte, /* Maximum length of zSql in bytes. */ 2975 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2976 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2977 ); 2978 SQLITE_API int sqlite3_prepare16_v2( 2979 sqlite3 *db, /* Database handle */ 2980 const void *zSql, /* SQL statement, UTF-16 encoded */ 2981 int nByte, /* Maximum length of zSql in bytes. */ 2982 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2983 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2984 ); 2985 2986 /* 2987 ** CAPI3REF: Retrieving Statement SQL 2988 ** 2989 ** ^This interface can be used to retrieve a saved copy of the original 2990 ** SQL text used to create a [prepared statement] if that statement was 2991 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2992 */ 2993 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt); 2994 2995 /* 2996 ** CAPI3REF: Determine If An SQL Statement Writes The Database 2997 ** 2998 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 2999 ** and only if the [prepared statement] X makes no direct changes to 3000 ** the content of the database file. 3001 ** 3002 ** Note that [application-defined SQL functions] or 3003 ** [virtual tables] might change the database indirectly as a side effect. 3004 ** ^(For example, if an application defines a function "eval()" that 3005 ** calls [sqlite3_exec()], then the following SQL statement would 3006 ** change the database file through side-effects: 3007 ** 3008 ** <blockquote><pre> 3009 ** SELECT eval('DELETE FROM t1') FROM t2; 3010 ** </pre></blockquote> 3011 ** 3012 ** But because the [SELECT] statement does not change the database file 3013 ** directly, sqlite3_stmt_readonly() would still return true.)^ 3014 ** 3015 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3016 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3017 ** since the statements themselves do not actually modify the database but 3018 ** rather they control the timing of when other statements modify the 3019 ** database. ^The [ATTACH] and [DETACH] statements also cause 3020 ** sqlite3_stmt_readonly() to return true since, while those statements 3021 ** change the configuration of a database connection, they do not make 3022 ** changes to the content of the database files on disk. 3023 */ 3024 SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3025 3026 /* 3027 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3028 ** 3029 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3030 ** [prepared statement] S has been stepped at least once using 3031 ** [sqlite3_step(S)] but has not run to completion and/or has not 3032 ** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3033 ** interface returns false if S is a NULL pointer. If S is not a 3034 ** NULL pointer and is not a pointer to a valid [prepared statement] 3035 ** object, then the behavior is undefined and probably undesirable. 3036 ** 3037 ** This interface can be used in combination [sqlite3_next_stmt()] 3038 ** to locate all prepared statements associated with a database 3039 ** connection that are in need of being reset. This can be used, 3040 ** for example, in diagnostic routines to search for prepared 3041 ** statements that are holding a transaction open. 3042 */ 3043 SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*); 3044 3045 /* 3046 ** CAPI3REF: Dynamically Typed Value Object 3047 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3048 ** 3049 ** SQLite uses the sqlite3_value object to represent all values 3050 ** that can be stored in a database table. SQLite uses dynamic typing 3051 ** for the values it stores. ^Values stored in sqlite3_value objects 3052 ** can be integers, floating point values, strings, BLOBs, or NULL. 3053 ** 3054 ** An sqlite3_value object may be either "protected" or "unprotected". 3055 ** Some interfaces require a protected sqlite3_value. Other interfaces 3056 ** will accept either a protected or an unprotected sqlite3_value. 3057 ** Every interface that accepts sqlite3_value arguments specifies 3058 ** whether or not it requires a protected sqlite3_value. 3059 ** 3060 ** The terms "protected" and "unprotected" refer to whether or not 3061 ** a mutex is held. An internal mutex is held for a protected 3062 ** sqlite3_value object but no mutex is held for an unprotected 3063 ** sqlite3_value object. If SQLite is compiled to be single-threaded 3064 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3065 ** or if SQLite is run in one of reduced mutex modes 3066 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3067 ** then there is no distinction between protected and unprotected 3068 ** sqlite3_value objects and they can be used interchangeably. However, 3069 ** for maximum code portability it is recommended that applications 3070 ** still make the distinction between protected and unprotected 3071 ** sqlite3_value objects even when not strictly required. 3072 ** 3073 ** ^The sqlite3_value objects that are passed as parameters into the 3074 ** implementation of [application-defined SQL functions] are protected. 3075 ** ^The sqlite3_value object returned by 3076 ** [sqlite3_column_value()] is unprotected. 3077 ** Unprotected sqlite3_value objects may only be used with 3078 ** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3079 ** The [sqlite3_value_blob | sqlite3_value_type()] family of 3080 ** interfaces require protected sqlite3_value objects. 3081 */ 3082 typedef struct Mem sqlite3_value; 3083 3084 /* 3085 ** CAPI3REF: SQL Function Context Object 3086 ** 3087 ** The context in which an SQL function executes is stored in an 3088 ** sqlite3_context object. ^A pointer to an sqlite3_context object 3089 ** is always first parameter to [application-defined SQL functions]. 3090 ** The application-defined SQL function implementation will pass this 3091 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3092 ** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3093 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3094 ** and/or [sqlite3_set_auxdata()]. 3095 */ 3096 typedef struct sqlite3_context sqlite3_context; 3097 3098 /* 3099 ** CAPI3REF: Binding Values To Prepared Statements 3100 ** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3101 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3102 ** 3103 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3104 ** literals may be replaced by a [parameter] that matches one of following 3105 ** templates: 3106 ** 3107 ** <ul> 3108 ** <li> ? 3109 ** <li> ?NNN 3110 ** <li> :VVV 3111 ** <li> @VVV 3112 ** <li> $VVV 3113 ** </ul> 3114 ** 3115 ** In the templates above, NNN represents an integer literal, 3116 ** and VVV represents an alphanumeric identifier.)^ ^The values of these 3117 ** parameters (also called "host parameter names" or "SQL parameters") 3118 ** can be set using the sqlite3_bind_*() routines defined here. 3119 ** 3120 ** ^The first argument to the sqlite3_bind_*() routines is always 3121 ** a pointer to the [sqlite3_stmt] object returned from 3122 ** [sqlite3_prepare_v2()] or its variants. 3123 ** 3124 ** ^The second argument is the index of the SQL parameter to be set. 3125 ** ^The leftmost SQL parameter has an index of 1. ^When the same named 3126 ** SQL parameter is used more than once, second and subsequent 3127 ** occurrences have the same index as the first occurrence. 3128 ** ^The index for named parameters can be looked up using the 3129 ** [sqlite3_bind_parameter_index()] API if desired. ^The index 3130 ** for "?NNN" parameters is the value of NNN. 3131 ** ^The NNN value must be between 1 and the [sqlite3_limit()] 3132 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3133 ** 3134 ** ^The third argument is the value to bind to the parameter. 3135 ** 3136 ** ^(In those routines that have a fourth argument, its value is the 3137 ** number of bytes in the parameter. To be clear: the value is the 3138 ** number of <u>bytes</u> in the value, not the number of characters.)^ 3139 ** ^If the fourth parameter is negative, the length of the string is 3140 ** the number of bytes up to the first zero terminator. 3141 ** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3142 ** or sqlite3_bind_text16() then that parameter must be the byte offset 3143 ** where the NUL terminator would occur assuming the string were NUL 3144 ** terminated. If any NUL characters occur at byte offsets less than 3145 ** the value of the fourth parameter then the resulting string value will 3146 ** contain embedded NULs. The result of expressions involving strings 3147 ** with embedded NULs is undefined. 3148 ** 3149 ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 3150 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 3151 ** string after SQLite has finished with it. ^The destructor is called 3152 ** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(), 3153 ** sqlite3_bind_text(), or sqlite3_bind_text16() fails. 3154 ** ^If the fifth argument is 3155 ** the special value [SQLITE_STATIC], then SQLite assumes that the 3156 ** information is in static, unmanaged space and does not need to be freed. 3157 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3158 ** SQLite makes its own private copy of the data immediately, before 3159 ** the sqlite3_bind_*() routine returns. 3160 ** 3161 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3162 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3163 ** (just an integer to hold its size) while it is being processed. 3164 ** Zeroblobs are intended to serve as placeholders for BLOBs whose 3165 ** content is later written using 3166 ** [sqlite3_blob_open | incremental BLOB I/O] routines. 3167 ** ^A negative value for the zeroblob results in a zero-length BLOB. 3168 ** 3169 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3170 ** for the [prepared statement] or with a prepared statement for which 3171 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3172 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3173 ** routine is passed a [prepared statement] that has been finalized, the 3174 ** result is undefined and probably harmful. 3175 ** 3176 ** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3177 ** ^Unbound parameters are interpreted as NULL. 3178 ** 3179 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3180 ** [error code] if anything goes wrong. 3181 ** ^[SQLITE_RANGE] is returned if the parameter 3182 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3183 ** 3184 ** See also: [sqlite3_bind_parameter_count()], 3185 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3186 */ 3187 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3188 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double); 3189 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int); 3190 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3191 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int); 3192 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 3193 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3194 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3195 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3196 3197 /* 3198 ** CAPI3REF: Number Of SQL Parameters 3199 ** 3200 ** ^This routine can be used to find the number of [SQL parameters] 3201 ** in a [prepared statement]. SQL parameters are tokens of the 3202 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3203 ** placeholders for values that are [sqlite3_bind_blob | bound] 3204 ** to the parameters at a later time. 3205 ** 3206 ** ^(This routine actually returns the index of the largest (rightmost) 3207 ** parameter. For all forms except ?NNN, this will correspond to the 3208 ** number of unique parameters. If parameters of the ?NNN form are used, 3209 ** there may be gaps in the list.)^ 3210 ** 3211 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 3212 ** [sqlite3_bind_parameter_name()], and 3213 ** [sqlite3_bind_parameter_index()]. 3214 */ 3215 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*); 3216 3217 /* 3218 ** CAPI3REF: Name Of A Host Parameter 3219 ** 3220 ** ^The sqlite3_bind_parameter_name(P,N) interface returns 3221 ** the name of the N-th [SQL parameter] in the [prepared statement] P. 3222 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3223 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3224 ** respectively. 3225 ** In other words, the initial ":" or "$" or "@" or "?" 3226 ** is included as part of the name.)^ 3227 ** ^Parameters of the form "?" without a following integer have no name 3228 ** and are referred to as "nameless" or "anonymous parameters". 3229 ** 3230 ** ^The first host parameter has an index of 1, not 0. 3231 ** 3232 ** ^If the value N is out of range or if the N-th parameter is 3233 ** nameless, then NULL is returned. ^The returned string is 3234 ** always in UTF-8 encoding even if the named parameter was 3235 ** originally specified as UTF-16 in [sqlite3_prepare16()] or 3236 ** [sqlite3_prepare16_v2()]. 3237 ** 3238 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 3239 ** [sqlite3_bind_parameter_count()], and 3240 ** [sqlite3_bind_parameter_index()]. 3241 */ 3242 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3243 3244 /* 3245 ** CAPI3REF: Index Of A Parameter With A Given Name 3246 ** 3247 ** ^Return the index of an SQL parameter given its name. ^The 3248 ** index value returned is suitable for use as the second 3249 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3250 ** is returned if no matching parameter is found. ^The parameter 3251 ** name must be given in UTF-8 even if the original statement 3252 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3253 ** 3254 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 3255 ** [sqlite3_bind_parameter_count()], and 3256 ** [sqlite3_bind_parameter_index()]. 3257 */ 3258 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3259 3260 /* 3261 ** CAPI3REF: Reset All Bindings On A Prepared Statement 3262 ** 3263 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3264 ** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3265 ** ^Use this routine to reset all host parameters to NULL. 3266 */ 3267 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*); 3268 3269 /* 3270 ** CAPI3REF: Number Of Columns In A Result Set 3271 ** 3272 ** ^Return the number of columns in the result set returned by the 3273 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3274 ** statement that does not return data (for example an [UPDATE]). 3275 ** 3276 ** See also: [sqlite3_data_count()] 3277 */ 3278 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt); 3279 3280 /* 3281 ** CAPI3REF: Column Names In A Result Set 3282 ** 3283 ** ^These routines return the name assigned to a particular column 3284 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3285 ** interface returns a pointer to a zero-terminated UTF-8 string 3286 ** and sqlite3_column_name16() returns a pointer to a zero-terminated 3287 ** UTF-16 string. ^The first parameter is the [prepared statement] 3288 ** that implements the [SELECT] statement. ^The second parameter is the 3289 ** column number. ^The leftmost column is number 0. 3290 ** 3291 ** ^The returned string pointer is valid until either the [prepared statement] 3292 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3293 ** reprepared by the first call to [sqlite3_step()] for a particular run 3294 ** or until the next call to 3295 ** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3296 ** 3297 ** ^If sqlite3_malloc() fails during the processing of either routine 3298 ** (for example during a conversion from UTF-8 to UTF-16) then a 3299 ** NULL pointer is returned. 3300 ** 3301 ** ^The name of a result column is the value of the "AS" clause for 3302 ** that column, if there is an AS clause. If there is no AS clause 3303 ** then the name of the column is unspecified and may change from 3304 ** one release of SQLite to the next. 3305 */ 3306 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N); 3307 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3308 3309 /* 3310 ** CAPI3REF: Source Of Data In A Query Result 3311 ** 3312 ** ^These routines provide a means to determine the database, table, and 3313 ** table column that is the origin of a particular result column in 3314 ** [SELECT] statement. 3315 ** ^The name of the database or table or column can be returned as 3316 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3317 ** the database name, the _table_ routines return the table name, and 3318 ** the origin_ routines return the column name. 3319 ** ^The returned string is valid until the [prepared statement] is destroyed 3320 ** using [sqlite3_finalize()] or until the statement is automatically 3321 ** reprepared by the first call to [sqlite3_step()] for a particular run 3322 ** or until the same information is requested 3323 ** again in a different encoding. 3324 ** 3325 ** ^The names returned are the original un-aliased names of the 3326 ** database, table, and column. 3327 ** 3328 ** ^The first argument to these interfaces is a [prepared statement]. 3329 ** ^These functions return information about the Nth result column returned by 3330 ** the statement, where N is the second function argument. 3331 ** ^The left-most column is column 0 for these routines. 3332 ** 3333 ** ^If the Nth column returned by the statement is an expression or 3334 ** subquery and is not a column value, then all of these functions return 3335 ** NULL. ^These routine might also return NULL if a memory allocation error 3336 ** occurs. ^Otherwise, they return the name of the attached database, table, 3337 ** or column that query result column was extracted from. 3338 ** 3339 ** ^As with all other SQLite APIs, those whose names end with "16" return 3340 ** UTF-16 encoded strings and the other functions return UTF-8. 3341 ** 3342 ** ^These APIs are only available if the library was compiled with the 3343 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3344 ** 3345 ** If two or more threads call one or more of these routines against the same 3346 ** prepared statement and column at the same time then the results are 3347 ** undefined. 3348 ** 3349 ** If two or more threads call one or more 3350 ** [sqlite3_column_database_name | column metadata interfaces] 3351 ** for the same [prepared statement] and result column 3352 ** at the same time then the results are undefined. 3353 */ 3354 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3355 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3356 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3357 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3358 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3359 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3360 3361 /* 3362 ** CAPI3REF: Declared Datatype Of A Query Result 3363 ** 3364 ** ^(The first parameter is a [prepared statement]. 3365 ** If this statement is a [SELECT] statement and the Nth column of the 3366 ** returned result set of that [SELECT] is a table column (not an 3367 ** expression or subquery) then the declared type of the table 3368 ** column is returned.)^ ^If the Nth column of the result set is an 3369 ** expression or subquery, then a NULL pointer is returned. 3370 ** ^The returned string is always UTF-8 encoded. 3371 ** 3372 ** ^(For example, given the database schema: 3373 ** 3374 ** CREATE TABLE t1(c1 VARIANT); 3375 ** 3376 ** and the following statement to be compiled: 3377 ** 3378 ** SELECT c1 + 1, c1 FROM t1; 3379 ** 3380 ** this routine would return the string "VARIANT" for the second result 3381 ** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3382 ** 3383 ** ^SQLite uses dynamic run-time typing. ^So just because a column 3384 ** is declared to contain a particular type does not mean that the 3385 ** data stored in that column is of the declared type. SQLite is 3386 ** strongly typed, but the typing is dynamic not static. ^Type 3387 ** is associated with individual values, not with the containers 3388 ** used to hold those values. 3389 */ 3390 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3391 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3392 3393 /* 3394 ** CAPI3REF: Evaluate An SQL Statement 3395 ** 3396 ** After a [prepared statement] has been prepared using either 3397 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3398 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3399 ** must be called one or more times to evaluate the statement. 3400 ** 3401 ** The details of the behavior of the sqlite3_step() interface depend 3402 ** on whether the statement was prepared using the newer "v2" interface 3403 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3404 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3405 ** new "v2" interface is recommended for new applications but the legacy 3406 ** interface will continue to be supported. 3407 ** 3408 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3409 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3410 ** ^With the "v2" interface, any of the other [result codes] or 3411 ** [extended result codes] might be returned as well. 3412 ** 3413 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3414 ** database locks it needs to do its job. ^If the statement is a [COMMIT] 3415 ** or occurs outside of an explicit transaction, then you can retry the 3416 ** statement. If the statement is not a [COMMIT] and occurs within an 3417 ** explicit transaction then you should rollback the transaction before 3418 ** continuing. 3419 ** 3420 ** ^[SQLITE_DONE] means that the statement has finished executing 3421 ** successfully. sqlite3_step() should not be called again on this virtual 3422 ** machine without first calling [sqlite3_reset()] to reset the virtual 3423 ** machine back to its initial state. 3424 ** 3425 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3426 ** is returned each time a new row of data is ready for processing by the 3427 ** caller. The values may be accessed using the [column access functions]. 3428 ** sqlite3_step() is called again to retrieve the next row of data. 3429 ** 3430 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3431 ** violation) has occurred. sqlite3_step() should not be called again on 3432 ** the VM. More information may be found by calling [sqlite3_errmsg()]. 3433 ** ^With the legacy interface, a more specific error code (for example, 3434 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3435 ** can be obtained by calling [sqlite3_reset()] on the 3436 ** [prepared statement]. ^In the "v2" interface, 3437 ** the more specific error code is returned directly by sqlite3_step(). 3438 ** 3439 ** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3440 ** Perhaps it was called on a [prepared statement] that has 3441 ** already been [sqlite3_finalize | finalized] or on one that had 3442 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3443 ** be the case that the same database connection is being used by two or 3444 ** more threads at the same moment in time. 3445 ** 3446 ** For all versions of SQLite up to and including 3.6.23.1, a call to 3447 ** [sqlite3_reset()] was required after sqlite3_step() returned anything 3448 ** other than [SQLITE_ROW] before any subsequent invocation of 3449 ** sqlite3_step(). Failure to reset the prepared statement using 3450 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3451 ** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3452 ** calling [sqlite3_reset()] automatically in this circumstance rather 3453 ** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3454 ** break because any application that ever receives an SQLITE_MISUSE error 3455 ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3456 ** can be used to restore the legacy behavior. 3457 ** 3458 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3459 ** API always returns a generic error code, [SQLITE_ERROR], following any 3460 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3461 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3462 ** specific [error codes] that better describes the error. 3463 ** We admit that this is a goofy design. The problem has been fixed 3464 ** with the "v2" interface. If you prepare all of your SQL statements 3465 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3466 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3467 ** then the more specific [error codes] are returned directly 3468 ** by sqlite3_step(). The use of the "v2" interface is recommended. 3469 */ 3470 SQLITE_API int sqlite3_step(sqlite3_stmt*); 3471 3472 /* 3473 ** CAPI3REF: Number of columns in a result set 3474 ** 3475 ** ^The sqlite3_data_count(P) interface returns the number of columns in the 3476 ** current row of the result set of [prepared statement] P. 3477 ** ^If prepared statement P does not have results ready to return 3478 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3479 ** interfaces) then sqlite3_data_count(P) returns 0. 3480 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3481 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 3482 ** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 3483 ** will return non-zero if previous call to [sqlite3_step](P) returned 3484 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 3485 ** where it always returns zero since each step of that multi-step 3486 ** pragma returns 0 columns of data. 3487 ** 3488 ** See also: [sqlite3_column_count()] 3489 */ 3490 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt); 3491 3492 /* 3493 ** CAPI3REF: Fundamental Datatypes 3494 ** KEYWORDS: SQLITE_TEXT 3495 ** 3496 ** ^(Every value in SQLite has one of five fundamental datatypes: 3497 ** 3498 ** <ul> 3499 ** <li> 64-bit signed integer 3500 ** <li> 64-bit IEEE floating point number 3501 ** <li> string 3502 ** <li> BLOB 3503 ** <li> NULL 3504 ** </ul>)^ 3505 ** 3506 ** These constants are codes for each of those types. 3507 ** 3508 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3509 ** for a completely different meaning. Software that links against both 3510 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3511 ** SQLITE_TEXT. 3512 */ 3513 #define SQLITE_INTEGER 1 3514 #define SQLITE_FLOAT 2 3515 #define SQLITE_BLOB 4 3516 #define SQLITE_NULL 5 3517 #ifdef SQLITE_TEXT 3518 # undef SQLITE_TEXT 3519 #else 3520 # define SQLITE_TEXT 3 3521 #endif 3522 #define SQLITE3_TEXT 3 3523 3524 /* 3525 ** CAPI3REF: Result Values From A Query 3526 ** KEYWORDS: {column access functions} 3527 ** 3528 ** These routines form the "result set" interface. 3529 ** 3530 ** ^These routines return information about a single column of the current 3531 ** result row of a query. ^In every case the first argument is a pointer 3532 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3533 ** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3534 ** and the second argument is the index of the column for which information 3535 ** should be returned. ^The leftmost column of the result set has the index 0. 3536 ** ^The number of columns in the result can be determined using 3537 ** [sqlite3_column_count()]. 3538 ** 3539 ** If the SQL statement does not currently point to a valid row, or if the 3540 ** column index is out of range, the result is undefined. 3541 ** These routines may only be called when the most recent call to 3542 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3543 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3544 ** If any of these routines are called after [sqlite3_reset()] or 3545 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3546 ** something other than [SQLITE_ROW], the results are undefined. 3547 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3548 ** are called from a different thread while any of these routines 3549 ** are pending, then the results are undefined. 3550 ** 3551 ** ^The sqlite3_column_type() routine returns the 3552 ** [SQLITE_INTEGER | datatype code] for the initial data type 3553 ** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3554 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3555 ** returned by sqlite3_column_type() is only meaningful if no type 3556 ** conversions have occurred as described below. After a type conversion, 3557 ** the value returned by sqlite3_column_type() is undefined. Future 3558 ** versions of SQLite may change the behavior of sqlite3_column_type() 3559 ** following a type conversion. 3560 ** 3561 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3562 ** routine returns the number of bytes in that BLOB or string. 3563 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3564 ** the string to UTF-8 and then returns the number of bytes. 3565 ** ^If the result is a numeric value then sqlite3_column_bytes() uses 3566 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3567 ** the number of bytes in that string. 3568 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3569 ** 3570 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3571 ** routine returns the number of bytes in that BLOB or string. 3572 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3573 ** the string to UTF-16 and then returns the number of bytes. 3574 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3575 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3576 ** the number of bytes in that string. 3577 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3578 ** 3579 ** ^The values returned by [sqlite3_column_bytes()] and 3580 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3581 ** of the string. ^For clarity: the values returned by 3582 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3583 ** bytes in the string, not the number of characters. 3584 ** 3585 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3586 ** even empty strings, are always zero-terminated. ^The return 3587 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3588 ** 3589 ** ^The object returned by [sqlite3_column_value()] is an 3590 ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3591 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3592 ** If the [unprotected sqlite3_value] object returned by 3593 ** [sqlite3_column_value()] is used in any other way, including calls 3594 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3595 ** or [sqlite3_value_bytes()], then the behavior is undefined. 3596 ** 3597 ** These routines attempt to convert the value where appropriate. ^For 3598 ** example, if the internal representation is FLOAT and a text result 3599 ** is requested, [sqlite3_snprintf()] is used internally to perform the 3600 ** conversion automatically. ^(The following table details the conversions 3601 ** that are applied: 3602 ** 3603 ** <blockquote> 3604 ** <table border="1"> 3605 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3606 ** 3607 ** <tr><td> NULL <td> INTEGER <td> Result is 0 3608 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3609 ** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3610 ** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3611 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3612 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3613 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3614 ** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3615 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3616 ** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3617 ** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3618 ** <tr><td> TEXT <td> FLOAT <td> Use atof() 3619 ** <tr><td> TEXT <td> BLOB <td> No change 3620 ** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3621 ** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3622 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3623 ** </table> 3624 ** </blockquote>)^ 3625 ** 3626 ** The table above makes reference to standard C library functions atoi() 3627 ** and atof(). SQLite does not really use these functions. It has its 3628 ** own equivalent internal routines. The atoi() and atof() names are 3629 ** used in the table for brevity and because they are familiar to most 3630 ** C programmers. 3631 ** 3632 ** Note that when type conversions occur, pointers returned by prior 3633 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3634 ** sqlite3_column_text16() may be invalidated. 3635 ** Type conversions and pointer invalidations might occur 3636 ** in the following cases: 3637 ** 3638 ** <ul> 3639 ** <li> The initial content is a BLOB and sqlite3_column_text() or 3640 ** sqlite3_column_text16() is called. A zero-terminator might 3641 ** need to be added to the string.</li> 3642 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3643 ** sqlite3_column_text16() is called. The content must be converted 3644 ** to UTF-16.</li> 3645 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3646 ** sqlite3_column_text() is called. The content must be converted 3647 ** to UTF-8.</li> 3648 ** </ul> 3649 ** 3650 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3651 ** not invalidate a prior pointer, though of course the content of the buffer 3652 ** that the prior pointer references will have been modified. Other kinds 3653 ** of conversion are done in place when it is possible, but sometimes they 3654 ** are not possible and in those cases prior pointers are invalidated. 3655 ** 3656 ** The safest and easiest to remember policy is to invoke these routines 3657 ** in one of the following ways: 3658 ** 3659 ** <ul> 3660 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3661 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3662 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3663 ** </ul> 3664 ** 3665 ** In other words, you should call sqlite3_column_text(), 3666 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3667 ** into the desired format, then invoke sqlite3_column_bytes() or 3668 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3669 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3670 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3671 ** with calls to sqlite3_column_bytes(). 3672 ** 3673 ** ^The pointers returned are valid until a type conversion occurs as 3674 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3675 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3676 ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3677 ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3678 ** [sqlite3_free()]. 3679 ** 3680 ** ^(If a memory allocation error occurs during the evaluation of any 3681 ** of these routines, a default value is returned. The default value 3682 ** is either the integer 0, the floating point number 0.0, or a NULL 3683 ** pointer. Subsequent calls to [sqlite3_errcode()] will return 3684 ** [SQLITE_NOMEM].)^ 3685 */ 3686 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3687 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3688 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3689 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol); 3690 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol); 3691 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3692 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3693 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3694 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol); 3695 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3696 3697 /* 3698 ** CAPI3REF: Destroy A Prepared Statement Object 3699 ** 3700 ** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3701 ** ^If the most recent evaluation of the statement encountered no errors 3702 ** or if the statement is never been evaluated, then sqlite3_finalize() returns 3703 ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 3704 ** sqlite3_finalize(S) returns the appropriate [error code] or 3705 ** [extended error code]. 3706 ** 3707 ** ^The sqlite3_finalize(S) routine can be called at any point during 3708 ** the life cycle of [prepared statement] S: 3709 ** before statement S is ever evaluated, after 3710 ** one or more calls to [sqlite3_reset()], or after any call 3711 ** to [sqlite3_step()] regardless of whether or not the statement has 3712 ** completed execution. 3713 ** 3714 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 3715 ** 3716 ** The application must finalize every [prepared statement] in order to avoid 3717 ** resource leaks. It is a grievous error for the application to try to use 3718 ** a prepared statement after it has been finalized. Any use of a prepared 3719 ** statement after it has been finalized can result in undefined and 3720 ** undesirable behavior such as segfaults and heap corruption. 3721 */ 3722 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt); 3723 3724 /* 3725 ** CAPI3REF: Reset A Prepared Statement Object 3726 ** 3727 ** The sqlite3_reset() function is called to reset a [prepared statement] 3728 ** object back to its initial state, ready to be re-executed. 3729 ** ^Any SQL statement variables that had values bound to them using 3730 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3731 ** Use [sqlite3_clear_bindings()] to reset the bindings. 3732 ** 3733 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3734 ** back to the beginning of its program. 3735 ** 3736 ** ^If the most recent call to [sqlite3_step(S)] for the 3737 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3738 ** or if [sqlite3_step(S)] has never before been called on S, 3739 ** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3740 ** 3741 ** ^If the most recent call to [sqlite3_step(S)] for the 3742 ** [prepared statement] S indicated an error, then 3743 ** [sqlite3_reset(S)] returns an appropriate [error code]. 3744 ** 3745 ** ^The [sqlite3_reset(S)] interface does not change the values 3746 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3747 */ 3748 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt); 3749 3750 /* 3751 ** CAPI3REF: Create Or Redefine SQL Functions 3752 ** KEYWORDS: {function creation routines} 3753 ** KEYWORDS: {application-defined SQL function} 3754 ** KEYWORDS: {application-defined SQL functions} 3755 ** 3756 ** ^These functions (collectively known as "function creation routines") 3757 ** are used to add SQL functions or aggregates or to redefine the behavior 3758 ** of existing SQL functions or aggregates. The only differences between 3759 ** these routines are the text encoding expected for 3760 ** the second parameter (the name of the function being created) 3761 ** and the presence or absence of a destructor callback for 3762 ** the application data pointer. 3763 ** 3764 ** ^The first parameter is the [database connection] to which the SQL 3765 ** function is to be added. ^If an application uses more than one database 3766 ** connection then application-defined SQL functions must be added 3767 ** to each database connection separately. 3768 ** 3769 ** ^The second parameter is the name of the SQL function to be created or 3770 ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 3771 ** representation, exclusive of the zero-terminator. ^Note that the name 3772 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 3773 ** ^Any attempt to create a function with a longer name 3774 ** will result in [SQLITE_MISUSE] being returned. 3775 ** 3776 ** ^The third parameter (nArg) 3777 ** is the number of arguments that the SQL function or 3778 ** aggregate takes. ^If this parameter is -1, then the SQL function or 3779 ** aggregate may take any number of arguments between 0 and the limit 3780 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3781 ** parameter is less than -1 or greater than 127 then the behavior is 3782 ** undefined. 3783 ** 3784 ** ^The fourth parameter, eTextRep, specifies what 3785 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3786 ** its parameters. Every SQL function implementation must be able to work 3787 ** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3788 ** more efficient with one encoding than another. ^An application may 3789 ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3790 ** times with the same function but with different values of eTextRep. 3791 ** ^When multiple implementations of the same function are available, SQLite 3792 ** will pick the one that involves the least amount of data conversion. 3793 ** If there is only a single implementation which does not care what text 3794 ** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3795 ** 3796 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3797 ** function can gain access to this pointer using [sqlite3_user_data()].)^ 3798 ** 3799 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 3800 ** pointers to C-language functions that implement the SQL function or 3801 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3802 ** callback only; NULL pointers must be passed as the xStep and xFinal 3803 ** parameters. ^An aggregate SQL function requires an implementation of xStep 3804 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 3805 ** SQL function or aggregate, pass NULL pointers for all three function 3806 ** callbacks. 3807 ** 3808 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 3809 ** then it is destructor for the application data pointer. 3810 ** The destructor is invoked when the function is deleted, either by being 3811 ** overloaded or when the database connection closes.)^ 3812 ** ^The destructor is also invoked if the call to 3813 ** sqlite3_create_function_v2() fails. 3814 ** ^When the destructor callback of the tenth parameter is invoked, it 3815 ** is passed a single argument which is a copy of the application data 3816 ** pointer which was the fifth parameter to sqlite3_create_function_v2(). 3817 ** 3818 ** ^It is permitted to register multiple implementations of the same 3819 ** functions with the same name but with either differing numbers of 3820 ** arguments or differing preferred text encodings. ^SQLite will use 3821 ** the implementation that most closely matches the way in which the 3822 ** SQL function is used. ^A function implementation with a non-negative 3823 ** nArg parameter is a better match than a function implementation with 3824 ** a negative nArg. ^A function where the preferred text encoding 3825 ** matches the database encoding is a better 3826 ** match than a function where the encoding is different. 3827 ** ^A function where the encoding difference is between UTF16le and UTF16be 3828 ** is a closer match than a function where the encoding difference is 3829 ** between UTF8 and UTF16. 3830 ** 3831 ** ^Built-in functions may be overloaded by new application-defined functions. 3832 ** 3833 ** ^An application-defined function is permitted to call other 3834 ** SQLite interfaces. However, such calls must not 3835 ** close the database connection nor finalize or reset the prepared 3836 ** statement in which the function is running. 3837 */ 3838 SQLITE_API int sqlite3_create_function( 3839 sqlite3 *db, 3840 const char *zFunctionName, 3841 int nArg, 3842 int eTextRep, 3843 void *pApp, 3844 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3845 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3846 void (*xFinal)(sqlite3_context*) 3847 ); 3848 SQLITE_API int sqlite3_create_function16( 3849 sqlite3 *db, 3850 const void *zFunctionName, 3851 int nArg, 3852 int eTextRep, 3853 void *pApp, 3854 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3855 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3856 void (*xFinal)(sqlite3_context*) 3857 ); 3858 SQLITE_API int sqlite3_create_function_v2( 3859 sqlite3 *db, 3860 const char *zFunctionName, 3861 int nArg, 3862 int eTextRep, 3863 void *pApp, 3864 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3865 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3866 void (*xFinal)(sqlite3_context*), 3867 void(*xDestroy)(void*) 3868 ); 3869 3870 /* 3871 ** CAPI3REF: Text Encodings 3872 ** 3873 ** These constant define integer codes that represent the various 3874 ** text encodings supported by SQLite. 3875 */ 3876 #define SQLITE_UTF8 1 3877 #define SQLITE_UTF16LE 2 3878 #define SQLITE_UTF16BE 3 3879 #define SQLITE_UTF16 4 /* Use native byte order */ 3880 #define SQLITE_ANY 5 /* sqlite3_create_function only */ 3881 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3882 3883 /* 3884 ** CAPI3REF: Deprecated Functions 3885 ** DEPRECATED 3886 ** 3887 ** These functions are [deprecated]. In order to maintain 3888 ** backwards compatibility with older code, these functions continue 3889 ** to be supported. However, new applications should avoid 3890 ** the use of these functions. To help encourage people to avoid 3891 ** using these functions, we are not going to tell you what they do. 3892 */ 3893 #ifndef SQLITE_OMIT_DEPRECATED 3894 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3895 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3896 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3897 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void); 3898 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3899 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3900 #endif 3901 3902 /* 3903 ** CAPI3REF: Obtaining SQL Function Parameter Values 3904 ** 3905 ** The C-language implementation of SQL functions and aggregates uses 3906 ** this set of interface routines to access the parameter values on 3907 ** the function or aggregate. 3908 ** 3909 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3910 ** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3911 ** define callbacks that implement the SQL functions and aggregates. 3912 ** The 3rd parameter to these callbacks is an array of pointers to 3913 ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3914 ** each parameter to the SQL function. These routines are used to 3915 ** extract values from the [sqlite3_value] objects. 3916 ** 3917 ** These routines work only with [protected sqlite3_value] objects. 3918 ** Any attempt to use these routines on an [unprotected sqlite3_value] 3919 ** object results in undefined behavior. 3920 ** 3921 ** ^These routines work just like the corresponding [column access functions] 3922 ** except that these routines take a single [protected sqlite3_value] object 3923 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3924 ** 3925 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string 3926 ** in the native byte-order of the host machine. ^The 3927 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3928 ** extract UTF-16 strings as big-endian and little-endian respectively. 3929 ** 3930 ** ^(The sqlite3_value_numeric_type() interface attempts to apply 3931 ** numeric affinity to the value. This means that an attempt is 3932 ** made to convert the value to an integer or floating point. If 3933 ** such a conversion is possible without loss of information (in other 3934 ** words, if the value is a string that looks like a number) 3935 ** then the conversion is performed. Otherwise no conversion occurs. 3936 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 3937 ** 3938 ** Please pay particular attention to the fact that the pointer returned 3939 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3940 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3941 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3942 ** or [sqlite3_value_text16()]. 3943 ** 3944 ** These routines must be called from the same thread as 3945 ** the SQL function that supplied the [sqlite3_value*] parameters. 3946 */ 3947 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*); 3948 SQLITE_API int sqlite3_value_bytes(sqlite3_value*); 3949 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*); 3950 SQLITE_API double sqlite3_value_double(sqlite3_value*); 3951 SQLITE_API int sqlite3_value_int(sqlite3_value*); 3952 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3953 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*); 3954 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*); 3955 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*); 3956 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*); 3957 SQLITE_API int sqlite3_value_type(sqlite3_value*); 3958 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*); 3959 3960 /* 3961 ** CAPI3REF: Obtain Aggregate Function Context 3962 ** 3963 ** Implementations of aggregate SQL functions use this 3964 ** routine to allocate memory for storing their state. 3965 ** 3966 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called 3967 ** for a particular aggregate function, SQLite 3968 ** allocates N of memory, zeroes out that memory, and returns a pointer 3969 ** to the new memory. ^On second and subsequent calls to 3970 ** sqlite3_aggregate_context() for the same aggregate function instance, 3971 ** the same buffer is returned. Sqlite3_aggregate_context() is normally 3972 ** called once for each invocation of the xStep callback and then one 3973 ** last time when the xFinal callback is invoked. ^(When no rows match 3974 ** an aggregate query, the xStep() callback of the aggregate function 3975 ** implementation is never called and xFinal() is called exactly once. 3976 ** In those cases, sqlite3_aggregate_context() might be called for the 3977 ** first time from within xFinal().)^ 3978 ** 3979 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is 3980 ** less than or equal to zero or if a memory allocate error occurs. 3981 ** 3982 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 3983 ** determined by the N parameter on first successful call. Changing the 3984 ** value of N in subsequent call to sqlite3_aggregate_context() within 3985 ** the same aggregate function instance will not resize the memory 3986 ** allocation.)^ 3987 ** 3988 ** ^SQLite automatically frees the memory allocated by 3989 ** sqlite3_aggregate_context() when the aggregate query concludes. 3990 ** 3991 ** The first parameter must be a copy of the 3992 ** [sqlite3_context | SQL function context] that is the first parameter 3993 ** to the xStep or xFinal callback routine that implements the aggregate 3994 ** function. 3995 ** 3996 ** This routine must be called from the same thread in which 3997 ** the aggregate SQL function is running. 3998 */ 3999 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4000 4001 /* 4002 ** CAPI3REF: User Data For Functions 4003 ** 4004 ** ^The sqlite3_user_data() interface returns a copy of 4005 ** the pointer that was the pUserData parameter (the 5th parameter) 4006 ** of the [sqlite3_create_function()] 4007 ** and [sqlite3_create_function16()] routines that originally 4008 ** registered the application defined function. 4009 ** 4010 ** This routine must be called from the same thread in which 4011 ** the application-defined function is running. 4012 */ 4013 SQLITE_API void *sqlite3_user_data(sqlite3_context*); 4014 4015 /* 4016 ** CAPI3REF: Database Connection For Functions 4017 ** 4018 ** ^The sqlite3_context_db_handle() interface returns a copy of 4019 ** the pointer to the [database connection] (the 1st parameter) 4020 ** of the [sqlite3_create_function()] 4021 ** and [sqlite3_create_function16()] routines that originally 4022 ** registered the application defined function. 4023 */ 4024 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4025 4026 /* 4027 ** CAPI3REF: Function Auxiliary Data 4028 ** 4029 ** The following two functions may be used by scalar SQL functions to 4030 ** associate metadata with argument values. If the same value is passed to 4031 ** multiple invocations of the same SQL function during query execution, under 4032 ** some circumstances the associated metadata may be preserved. This may 4033 ** be used, for example, to add a regular-expression matching scalar 4034 ** function. The compiled version of the regular expression is stored as 4035 ** metadata associated with the SQL value passed as the regular expression 4036 ** pattern. The compiled regular expression can be reused on multiple 4037 ** invocations of the same function so that the original pattern string 4038 ** does not need to be recompiled on each invocation. 4039 ** 4040 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4041 ** associated by the sqlite3_set_auxdata() function with the Nth argument 4042 ** value to the application-defined function. ^If no metadata has been ever 4043 ** been set for the Nth argument of the function, or if the corresponding 4044 ** function parameter has changed since the meta-data was set, 4045 ** then sqlite3_get_auxdata() returns a NULL pointer. 4046 ** 4047 ** ^The sqlite3_set_auxdata() interface saves the metadata 4048 ** pointed to by its 3rd parameter as the metadata for the N-th 4049 ** argument of the application-defined function. Subsequent 4050 ** calls to sqlite3_get_auxdata() might return this data, if it has 4051 ** not been destroyed. 4052 ** ^If it is not NULL, SQLite will invoke the destructor 4053 ** function given by the 4th parameter to sqlite3_set_auxdata() on 4054 ** the metadata when the corresponding function parameter changes 4055 ** or when the SQL statement completes, whichever comes first. 4056 ** 4057 ** SQLite is free to call the destructor and drop metadata on any 4058 ** parameter of any function at any time. ^The only guarantee is that 4059 ** the destructor will be called before the metadata is dropped. 4060 ** 4061 ** ^(In practice, metadata is preserved between function calls for 4062 ** expressions that are constant at compile time. This includes literal 4063 ** values and [parameters].)^ 4064 ** 4065 ** These routines must be called from the same thread in which 4066 ** the SQL function is running. 4067 */ 4068 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N); 4069 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4070 4071 4072 /* 4073 ** CAPI3REF: Constants Defining Special Destructor Behavior 4074 ** 4075 ** These are special values for the destructor that is passed in as the 4076 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4077 ** argument is SQLITE_STATIC, it means that the content pointer is constant 4078 ** and will never change. It does not need to be destroyed. ^The 4079 ** SQLITE_TRANSIENT value means that the content will likely change in 4080 ** the near future and that SQLite should make its own private copy of 4081 ** the content before returning. 4082 ** 4083 ** The typedef is necessary to work around problems in certain 4084 ** C++ compilers. See ticket #2191. 4085 */ 4086 typedef void (*sqlite3_destructor_type)(void*); 4087 #define SQLITE_STATIC ((sqlite3_destructor_type)0) 4088 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4089 4090 /* 4091 ** CAPI3REF: Setting The Result Of An SQL Function 4092 ** 4093 ** These routines are used by the xFunc or xFinal callbacks that 4094 ** implement SQL functions and aggregates. See 4095 ** [sqlite3_create_function()] and [sqlite3_create_function16()] 4096 ** for additional information. 4097 ** 4098 ** These functions work very much like the [parameter binding] family of 4099 ** functions used to bind values to host parameters in prepared statements. 4100 ** Refer to the [SQL parameter] documentation for additional information. 4101 ** 4102 ** ^The sqlite3_result_blob() interface sets the result from 4103 ** an application-defined function to be the BLOB whose content is pointed 4104 ** to by the second parameter and which is N bytes long where N is the 4105 ** third parameter. 4106 ** 4107 ** ^The sqlite3_result_zeroblob() interfaces set the result of 4108 ** the application-defined function to be a BLOB containing all zero 4109 ** bytes and N bytes in size, where N is the value of the 2nd parameter. 4110 ** 4111 ** ^The sqlite3_result_double() interface sets the result from 4112 ** an application-defined function to be a floating point value specified 4113 ** by its 2nd argument. 4114 ** 4115 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4116 ** cause the implemented SQL function to throw an exception. 4117 ** ^SQLite uses the string pointed to by the 4118 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4119 ** as the text of an error message. ^SQLite interprets the error 4120 ** message string from sqlite3_result_error() as UTF-8. ^SQLite 4121 ** interprets the string from sqlite3_result_error16() as UTF-16 in native 4122 ** byte order. ^If the third parameter to sqlite3_result_error() 4123 ** or sqlite3_result_error16() is negative then SQLite takes as the error 4124 ** message all text up through the first zero character. 4125 ** ^If the third parameter to sqlite3_result_error() or 4126 ** sqlite3_result_error16() is non-negative then SQLite takes that many 4127 ** bytes (not characters) from the 2nd parameter as the error message. 4128 ** ^The sqlite3_result_error() and sqlite3_result_error16() 4129 ** routines make a private copy of the error message text before 4130 ** they return. Hence, the calling function can deallocate or 4131 ** modify the text after they return without harm. 4132 ** ^The sqlite3_result_error_code() function changes the error code 4133 ** returned by SQLite as a result of an error in a function. ^By default, 4134 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4135 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4136 ** 4137 ** ^The sqlite3_result_toobig() interface causes SQLite to throw an error 4138 ** indicating that a string or BLOB is too long to represent. 4139 ** 4140 ** ^The sqlite3_result_nomem() interface causes SQLite to throw an error 4141 ** indicating that a memory allocation failed. 4142 ** 4143 ** ^The sqlite3_result_int() interface sets the return value 4144 ** of the application-defined function to be the 32-bit signed integer 4145 ** value given in the 2nd argument. 4146 ** ^The sqlite3_result_int64() interface sets the return value 4147 ** of the application-defined function to be the 64-bit signed integer 4148 ** value given in the 2nd argument. 4149 ** 4150 ** ^The sqlite3_result_null() interface sets the return value 4151 ** of the application-defined function to be NULL. 4152 ** 4153 ** ^The sqlite3_result_text(), sqlite3_result_text16(), 4154 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4155 ** set the return value of the application-defined function to be 4156 ** a text string which is represented as UTF-8, UTF-16 native byte order, 4157 ** UTF-16 little endian, or UTF-16 big endian, respectively. 4158 ** ^SQLite takes the text result from the application from 4159 ** the 2nd parameter of the sqlite3_result_text* interfaces. 4160 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4161 ** is negative, then SQLite takes result text from the 2nd parameter 4162 ** through the first zero character. 4163 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4164 ** is non-negative, then as many bytes (not characters) of the text 4165 ** pointed to by the 2nd parameter are taken as the application-defined 4166 ** function result. If the 3rd parameter is non-negative, then it 4167 ** must be the byte offset into the string where the NUL terminator would 4168 ** appear if the string where NUL terminated. If any NUL characters occur 4169 ** in the string at a byte offset that is less than the value of the 3rd 4170 ** parameter, then the resulting string will contain embedded NULs and the 4171 ** result of expressions operating on strings with embedded NULs is undefined. 4172 ** ^If the 4th parameter to the sqlite3_result_text* interfaces 4173 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4174 ** function as the destructor on the text or BLOB result when it has 4175 ** finished using that result. 4176 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4177 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4178 ** assumes that the text or BLOB result is in constant space and does not 4179 ** copy the content of the parameter nor call a destructor on the content 4180 ** when it has finished using that result. 4181 ** ^If the 4th parameter to the sqlite3_result_text* interfaces 4182 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4183 ** then SQLite makes a copy of the result into space obtained from 4184 ** from [sqlite3_malloc()] before it returns. 4185 ** 4186 ** ^The sqlite3_result_value() interface sets the result of 4187 ** the application-defined function to be a copy the 4188 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4189 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4190 ** so that the [sqlite3_value] specified in the parameter may change or 4191 ** be deallocated after sqlite3_result_value() returns without harm. 4192 ** ^A [protected sqlite3_value] object may always be used where an 4193 ** [unprotected sqlite3_value] object is required, so either 4194 ** kind of [sqlite3_value] object can be used with this interface. 4195 ** 4196 ** If these routines are called from within the different thread 4197 ** than the one containing the application-defined function that received 4198 ** the [sqlite3_context] pointer, the results are undefined. 4199 */ 4200 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4201 SQLITE_API void sqlite3_result_double(sqlite3_context*, double); 4202 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int); 4203 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int); 4204 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*); 4205 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*); 4206 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int); 4207 SQLITE_API void sqlite3_result_int(sqlite3_context*, int); 4208 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4209 SQLITE_API void sqlite3_result_null(sqlite3_context*); 4210 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4211 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4212 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4213 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4214 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4215 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n); 4216 4217 /* 4218 ** CAPI3REF: Define New Collating Sequences 4219 ** 4220 ** ^These functions add, remove, or modify a [collation] associated 4221 ** with the [database connection] specified as the first argument. 4222 ** 4223 ** ^The name of the collation is a UTF-8 string 4224 ** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4225 ** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4226 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4227 ** considered to be the same name. 4228 ** 4229 ** ^(The third argument (eTextRep) must be one of the constants: 4230 ** <ul> 4231 ** <li> [SQLITE_UTF8], 4232 ** <li> [SQLITE_UTF16LE], 4233 ** <li> [SQLITE_UTF16BE], 4234 ** <li> [SQLITE_UTF16], or 4235 ** <li> [SQLITE_UTF16_ALIGNED]. 4236 ** </ul>)^ 4237 ** ^The eTextRep argument determines the encoding of strings passed 4238 ** to the collating function callback, xCallback. 4239 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4240 ** force strings to be UTF16 with native byte order. 4241 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4242 ** on an even byte address. 4243 ** 4244 ** ^The fourth argument, pArg, is an application data pointer that is passed 4245 ** through as the first argument to the collating function callback. 4246 ** 4247 ** ^The fifth argument, xCallback, is a pointer to the collating function. 4248 ** ^Multiple collating functions can be registered using the same name but 4249 ** with different eTextRep parameters and SQLite will use whichever 4250 ** function requires the least amount of data transformation. 4251 ** ^If the xCallback argument is NULL then the collating function is 4252 ** deleted. ^When all collating functions having the same name are deleted, 4253 ** that collation is no longer usable. 4254 ** 4255 ** ^The collating function callback is invoked with a copy of the pArg 4256 ** application data pointer and with two strings in the encoding specified 4257 ** by the eTextRep argument. The collating function must return an 4258 ** integer that is negative, zero, or positive 4259 ** if the first string is less than, equal to, or greater than the second, 4260 ** respectively. A collating function must always return the same answer 4261 ** given the same inputs. If two or more collating functions are registered 4262 ** to the same collation name (using different eTextRep values) then all 4263 ** must give an equivalent answer when invoked with equivalent strings. 4264 ** The collating function must obey the following properties for all 4265 ** strings A, B, and C: 4266 ** 4267 ** <ol> 4268 ** <li> If A==B then B==A. 4269 ** <li> If A==B and B==C then A==C. 4270 ** <li> If A<B THEN B>A. 4271 ** <li> If A<B and B<C then A<C. 4272 ** </ol> 4273 ** 4274 ** If a collating function fails any of the above constraints and that 4275 ** collating function is registered and used, then the behavior of SQLite 4276 ** is undefined. 4277 ** 4278 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4279 ** with the addition that the xDestroy callback is invoked on pArg when 4280 ** the collating function is deleted. 4281 ** ^Collating functions are deleted when they are overridden by later 4282 ** calls to the collation creation functions or when the 4283 ** [database connection] is closed using [sqlite3_close()]. 4284 ** 4285 ** ^The xDestroy callback is <u>not</u> called if the 4286 ** sqlite3_create_collation_v2() function fails. Applications that invoke 4287 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4288 ** check the return code and dispose of the application data pointer 4289 ** themselves rather than expecting SQLite to deal with it for them. 4290 ** This is different from every other SQLite interface. The inconsistency 4291 ** is unfortunate but cannot be changed without breaking backwards 4292 ** compatibility. 4293 ** 4294 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4295 */ 4296 SQLITE_API int sqlite3_create_collation( 4297 sqlite3*, 4298 const char *zName, 4299 int eTextRep, 4300 void *pArg, 4301 int(*xCompare)(void*,int,const void*,int,const void*) 4302 ); 4303 SQLITE_API int sqlite3_create_collation_v2( 4304 sqlite3*, 4305 const char *zName, 4306 int eTextRep, 4307 void *pArg, 4308 int(*xCompare)(void*,int,const void*,int,const void*), 4309 void(*xDestroy)(void*) 4310 ); 4311 SQLITE_API int sqlite3_create_collation16( 4312 sqlite3*, 4313 const void *zName, 4314 int eTextRep, 4315 void *pArg, 4316 int(*xCompare)(void*,int,const void*,int,const void*) 4317 ); 4318 4319 /* 4320 ** CAPI3REF: Collation Needed Callbacks 4321 ** 4322 ** ^To avoid having to register all collation sequences before a database 4323 ** can be used, a single callback function may be registered with the 4324 ** [database connection] to be invoked whenever an undefined collation 4325 ** sequence is required. 4326 ** 4327 ** ^If the function is registered using the sqlite3_collation_needed() API, 4328 ** then it is passed the names of undefined collation sequences as strings 4329 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4330 ** the names are passed as UTF-16 in machine native byte order. 4331 ** ^A call to either function replaces the existing collation-needed callback. 4332 ** 4333 ** ^(When the callback is invoked, the first argument passed is a copy 4334 ** of the second argument to sqlite3_collation_needed() or 4335 ** sqlite3_collation_needed16(). The second argument is the database 4336 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4337 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4338 ** sequence function required. The fourth parameter is the name of the 4339 ** required collation sequence.)^ 4340 ** 4341 ** The callback function should register the desired collation using 4342 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4343 ** [sqlite3_create_collation_v2()]. 4344 */ 4345 SQLITE_API int sqlite3_collation_needed( 4346 sqlite3*, 4347 void*, 4348 void(*)(void*,sqlite3*,int eTextRep,const char*) 4349 ); 4350 SQLITE_API int sqlite3_collation_needed16( 4351 sqlite3*, 4352 void*, 4353 void(*)(void*,sqlite3*,int eTextRep,const void*) 4354 ); 4355 4356 #ifdef SQLITE_HAS_CODEC 4357 /* 4358 ** Specify the key for an encrypted database. This routine should be 4359 ** called right after sqlite3_open(). 4360 ** 4361 ** The code to implement this API is not available in the public release 4362 ** of SQLite. 4363 */ 4364 SQLITE_API int sqlite3_key( 4365 sqlite3 *db, /* Database to be rekeyed */ 4366 const void *pKey, int nKey /* The key */ 4367 ); 4368 4369 /* 4370 ** Change the key on an open database. If the current database is not 4371 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4372 ** database is decrypted. 4373 ** 4374 ** The code to implement this API is not available in the public release 4375 ** of SQLite. 4376 */ 4377 SQLITE_API int sqlite3_rekey( 4378 sqlite3 *db, /* Database to be rekeyed */ 4379 const void *pKey, int nKey /* The new key */ 4380 ); 4381 4382 /* 4383 ** Specify the activation key for a SEE database. Unless 4384 ** activated, none of the SEE routines will work. 4385 */ 4386 SQLITE_API void sqlite3_activate_see( 4387 const char *zPassPhrase /* Activation phrase */ 4388 ); 4389 #endif 4390 4391 #ifdef SQLITE_ENABLE_CEROD 4392 /* 4393 ** Specify the activation key for a CEROD database. Unless 4394 ** activated, none of the CEROD routines will work. 4395 */ 4396 SQLITE_API void sqlite3_activate_cerod( 4397 const char *zPassPhrase /* Activation phrase */ 4398 ); 4399 #endif 4400 4401 /* 4402 ** CAPI3REF: Suspend Execution For A Short Time 4403 ** 4404 ** The sqlite3_sleep() function causes the current thread to suspend execution 4405 ** for at least a number of milliseconds specified in its parameter. 4406 ** 4407 ** If the operating system does not support sleep requests with 4408 ** millisecond time resolution, then the time will be rounded up to 4409 ** the nearest second. The number of milliseconds of sleep actually 4410 ** requested from the operating system is returned. 4411 ** 4412 ** ^SQLite implements this interface by calling the xSleep() 4413 ** method of the default [sqlite3_vfs] object. If the xSleep() method 4414 ** of the default VFS is not implemented correctly, or not implemented at 4415 ** all, then the behavior of sqlite3_sleep() may deviate from the description 4416 ** in the previous paragraphs. 4417 */ 4418 SQLITE_API int sqlite3_sleep(int); 4419 4420 /* 4421 ** CAPI3REF: Name Of The Folder Holding Temporary Files 4422 ** 4423 ** ^(If this global variable is made to point to a string which is 4424 ** the name of a folder (a.k.a. directory), then all temporary files 4425 ** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4426 ** will be placed in that directory.)^ ^If this variable 4427 ** is a NULL pointer, then SQLite performs a search for an appropriate 4428 ** temporary file directory. 4429 ** 4430 ** It is not safe to read or modify this variable in more than one 4431 ** thread at a time. It is not safe to read or modify this variable 4432 ** if a [database connection] is being used at the same time in a separate 4433 ** thread. 4434 ** It is intended that this variable be set once 4435 ** as part of process initialization and before any SQLite interface 4436 ** routines have been called and that this variable remain unchanged 4437 ** thereafter. 4438 ** 4439 ** ^The [temp_store_directory pragma] may modify this variable and cause 4440 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4441 ** the [temp_store_directory pragma] always assumes that any string 4442 ** that this variable points to is held in memory obtained from 4443 ** [sqlite3_malloc] and the pragma may attempt to free that memory 4444 ** using [sqlite3_free]. 4445 ** Hence, if this variable is modified directly, either it should be 4446 ** made NULL or made to point to memory obtained from [sqlite3_malloc] 4447 ** or else the use of the [temp_store_directory pragma] should be avoided. 4448 */ 4449 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory; 4450 4451 /* 4452 ** CAPI3REF: Test For Auto-Commit Mode 4453 ** KEYWORDS: {autocommit mode} 4454 ** 4455 ** ^The sqlite3_get_autocommit() interface returns non-zero or 4456 ** zero if the given database connection is or is not in autocommit mode, 4457 ** respectively. ^Autocommit mode is on by default. 4458 ** ^Autocommit mode is disabled by a [BEGIN] statement. 4459 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 4460 ** 4461 ** If certain kinds of errors occur on a statement within a multi-statement 4462 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 4463 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 4464 ** transaction might be rolled back automatically. The only way to 4465 ** find out whether SQLite automatically rolled back the transaction after 4466 ** an error is to use this function. 4467 ** 4468 ** If another thread changes the autocommit status of the database 4469 ** connection while this routine is running, then the return value 4470 ** is undefined. 4471 */ 4472 SQLITE_API int sqlite3_get_autocommit(sqlite3*); 4473 4474 /* 4475 ** CAPI3REF: Find The Database Handle Of A Prepared Statement 4476 ** 4477 ** ^The sqlite3_db_handle interface returns the [database connection] handle 4478 ** to which a [prepared statement] belongs. ^The [database connection] 4479 ** returned by sqlite3_db_handle is the same [database connection] 4480 ** that was the first argument 4481 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 4482 ** create the statement in the first place. 4483 */ 4484 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 4485 4486 /* 4487 ** CAPI3REF: Return The Filename For A Database Connection 4488 ** 4489 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 4490 ** associated with database N of connection D. ^The main database file 4491 ** has the name "main". If there is no attached database N on the database 4492 ** connection D, or if database N is a temporary or in-memory database, then 4493 ** a NULL pointer is returned. 4494 ** 4495 ** ^The filename returned by this function is the output of the 4496 ** xFullPathname method of the [VFS]. ^In other words, the filename 4497 ** will be an absolute pathname, even if the filename used 4498 ** to open the database originally was a URI or relative pathname. 4499 */ 4500 SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 4501 4502 /* 4503 ** CAPI3REF: Determine if a database is read-only 4504 ** 4505 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 4506 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not 4507 ** the name of a database on connection D. 4508 */ 4509 SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 4510 4511 /* 4512 ** CAPI3REF: Find the next prepared statement 4513 ** 4514 ** ^This interface returns a pointer to the next [prepared statement] after 4515 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 4516 ** then this interface returns a pointer to the first prepared statement 4517 ** associated with the database connection pDb. ^If no prepared statement 4518 ** satisfies the conditions of this routine, it returns NULL. 4519 ** 4520 ** The [database connection] pointer D in a call to 4521 ** [sqlite3_next_stmt(D,S)] must refer to an open database 4522 ** connection and in particular must not be a NULL pointer. 4523 */ 4524 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 4525 4526 /* 4527 ** CAPI3REF: Commit And Rollback Notification Callbacks 4528 ** 4529 ** ^The sqlite3_commit_hook() interface registers a callback 4530 ** function to be invoked whenever a transaction is [COMMIT | committed]. 4531 ** ^Any callback set by a previous call to sqlite3_commit_hook() 4532 ** for the same database connection is overridden. 4533 ** ^The sqlite3_rollback_hook() interface registers a callback 4534 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 4535 ** ^Any callback set by a previous call to sqlite3_rollback_hook() 4536 ** for the same database connection is overridden. 4537 ** ^The pArg argument is passed through to the callback. 4538 ** ^If the callback on a commit hook function returns non-zero, 4539 ** then the commit is converted into a rollback. 4540 ** 4541 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 4542 ** return the P argument from the previous call of the same function 4543 ** on the same [database connection] D, or NULL for 4544 ** the first call for each function on D. 4545 ** 4546 ** The commit and rollback hook callbacks are not reentrant. 4547 ** The callback implementation must not do anything that will modify 4548 ** the database connection that invoked the callback. Any actions 4549 ** to modify the database connection must be deferred until after the 4550 ** completion of the [sqlite3_step()] call that triggered the commit 4551 ** or rollback hook in the first place. 4552 ** Note that running any other SQL statements, including SELECT statements, 4553 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 4554 ** the database connections for the meaning of "modify" in this paragraph. 4555 ** 4556 ** ^Registering a NULL function disables the callback. 4557 ** 4558 ** ^When the commit hook callback routine returns zero, the [COMMIT] 4559 ** operation is allowed to continue normally. ^If the commit hook 4560 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 4561 ** ^The rollback hook is invoked on a rollback that results from a commit 4562 ** hook returning non-zero, just as it would be with any other rollback. 4563 ** 4564 ** ^For the purposes of this API, a transaction is said to have been 4565 ** rolled back if an explicit "ROLLBACK" statement is executed, or 4566 ** an error or constraint causes an implicit rollback to occur. 4567 ** ^The rollback callback is not invoked if a transaction is 4568 ** automatically rolled back because the database connection is closed. 4569 ** 4570 ** See also the [sqlite3_update_hook()] interface. 4571 */ 4572 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 4573 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 4574 4575 /* 4576 ** CAPI3REF: Data Change Notification Callbacks 4577 ** 4578 ** ^The sqlite3_update_hook() interface registers a callback function 4579 ** with the [database connection] identified by the first argument 4580 ** to be invoked whenever a row is updated, inserted or deleted. 4581 ** ^Any callback set by a previous call to this function 4582 ** for the same database connection is overridden. 4583 ** 4584 ** ^The second argument is a pointer to the function to invoke when a 4585 ** row is updated, inserted or deleted. 4586 ** ^The first argument to the callback is a copy of the third argument 4587 ** to sqlite3_update_hook(). 4588 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 4589 ** or [SQLITE_UPDATE], depending on the operation that caused the callback 4590 ** to be invoked. 4591 ** ^The third and fourth arguments to the callback contain pointers to the 4592 ** database and table name containing the affected row. 4593 ** ^The final callback parameter is the [rowid] of the row. 4594 ** ^In the case of an update, this is the [rowid] after the update takes place. 4595 ** 4596 ** ^(The update hook is not invoked when internal system tables are 4597 ** modified (i.e. sqlite_master and sqlite_sequence).)^ 4598 ** 4599 ** ^In the current implementation, the update hook 4600 ** is not invoked when duplication rows are deleted because of an 4601 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 4602 ** invoked when rows are deleted using the [truncate optimization]. 4603 ** The exceptions defined in this paragraph might change in a future 4604 ** release of SQLite. 4605 ** 4606 ** The update hook implementation must not do anything that will modify 4607 ** the database connection that invoked the update hook. Any actions 4608 ** to modify the database connection must be deferred until after the 4609 ** completion of the [sqlite3_step()] call that triggered the update hook. 4610 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4611 ** database connections for the meaning of "modify" in this paragraph. 4612 ** 4613 ** ^The sqlite3_update_hook(D,C,P) function 4614 ** returns the P argument from the previous call 4615 ** on the same [database connection] D, or NULL for 4616 ** the first call on D. 4617 ** 4618 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4619 ** interfaces. 4620 */ 4621 SQLITE_API void *sqlite3_update_hook( 4622 sqlite3*, 4623 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4624 void* 4625 ); 4626 4627 /* 4628 ** CAPI3REF: Enable Or Disable Shared Pager Cache 4629 ** KEYWORDS: {shared cache} 4630 ** 4631 ** ^(This routine enables or disables the sharing of the database cache 4632 ** and schema data structures between [database connection | connections] 4633 ** to the same database. Sharing is enabled if the argument is true 4634 ** and disabled if the argument is false.)^ 4635 ** 4636 ** ^Cache sharing is enabled and disabled for an entire process. 4637 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4638 ** sharing was enabled or disabled for each thread separately. 4639 ** 4640 ** ^(The cache sharing mode set by this interface effects all subsequent 4641 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4642 ** Existing database connections continue use the sharing mode 4643 ** that was in effect at the time they were opened.)^ 4644 ** 4645 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4646 ** successfully. An [error code] is returned otherwise.)^ 4647 ** 4648 ** ^Shared cache is disabled by default. But this might change in 4649 ** future releases of SQLite. Applications that care about shared 4650 ** cache setting should set it explicitly. 4651 ** 4652 ** See Also: [SQLite Shared-Cache Mode] 4653 */ 4654 SQLITE_API int sqlite3_enable_shared_cache(int); 4655 4656 /* 4657 ** CAPI3REF: Attempt To Free Heap Memory 4658 ** 4659 ** ^The sqlite3_release_memory() interface attempts to free N bytes 4660 ** of heap memory by deallocating non-essential memory allocations 4661 ** held by the database library. Memory used to cache database 4662 ** pages to improve performance is an example of non-essential memory. 4663 ** ^sqlite3_release_memory() returns the number of bytes actually freed, 4664 ** which might be more or less than the amount requested. 4665 ** ^The sqlite3_release_memory() routine is a no-op returning zero 4666 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4667 ** 4668 ** See also: [sqlite3_db_release_memory()] 4669 */ 4670 SQLITE_API int sqlite3_release_memory(int); 4671 4672 /* 4673 ** CAPI3REF: Free Memory Used By A Database Connection 4674 ** 4675 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 4676 ** memory as possible from database connection D. Unlike the 4677 ** [sqlite3_release_memory()] interface, this interface is effect even 4678 ** when then [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 4679 ** omitted. 4680 ** 4681 ** See also: [sqlite3_release_memory()] 4682 */ 4683 SQLITE_API int sqlite3_db_release_memory(sqlite3*); 4684 4685 /* 4686 ** CAPI3REF: Impose A Limit On Heap Size 4687 ** 4688 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 4689 ** soft limit on the amount of heap memory that may be allocated by SQLite. 4690 ** ^SQLite strives to keep heap memory utilization below the soft heap 4691 ** limit by reducing the number of pages held in the page cache 4692 ** as heap memory usages approaches the limit. 4693 ** ^The soft heap limit is "soft" because even though SQLite strives to stay 4694 ** below the limit, it will exceed the limit rather than generate 4695 ** an [SQLITE_NOMEM] error. In other words, the soft heap limit 4696 ** is advisory only. 4697 ** 4698 ** ^The return value from sqlite3_soft_heap_limit64() is the size of 4699 ** the soft heap limit prior to the call, or negative in the case of an 4700 ** error. ^If the argument N is negative 4701 ** then no change is made to the soft heap limit. Hence, the current 4702 ** size of the soft heap limit can be determined by invoking 4703 ** sqlite3_soft_heap_limit64() with a negative argument. 4704 ** 4705 ** ^If the argument N is zero then the soft heap limit is disabled. 4706 ** 4707 ** ^(The soft heap limit is not enforced in the current implementation 4708 ** if one or more of following conditions are true: 4709 ** 4710 ** <ul> 4711 ** <li> The soft heap limit is set to zero. 4712 ** <li> Memory accounting is disabled using a combination of the 4713 ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 4714 ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 4715 ** <li> An alternative page cache implementation is specified using 4716 ** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 4717 ** <li> The page cache allocates from its own memory pool supplied 4718 ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 4719 ** from the heap. 4720 ** </ul>)^ 4721 ** 4722 ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 4723 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 4724 ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 4725 ** the soft heap limit is enforced on every memory allocation. Without 4726 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 4727 ** when memory is allocated by the page cache. Testing suggests that because 4728 ** the page cache is the predominate memory user in SQLite, most 4729 ** applications will achieve adequate soft heap limit enforcement without 4730 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4731 ** 4732 ** The circumstances under which SQLite will enforce the soft heap limit may 4733 ** changes in future releases of SQLite. 4734 */ 4735 SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 4736 4737 /* 4738 ** CAPI3REF: Deprecated Soft Heap Limit Interface 4739 ** DEPRECATED 4740 ** 4741 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 4742 ** interface. This routine is provided for historical compatibility 4743 ** only. All new applications should use the 4744 ** [sqlite3_soft_heap_limit64()] interface rather than this one. 4745 */ 4746 SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 4747 4748 4749 /* 4750 ** CAPI3REF: Extract Metadata About A Column Of A Table 4751 ** 4752 ** ^This routine returns metadata about a specific column of a specific 4753 ** database table accessible using the [database connection] handle 4754 ** passed as the first function argument. 4755 ** 4756 ** ^The column is identified by the second, third and fourth parameters to 4757 ** this function. ^The second parameter is either the name of the database 4758 ** (i.e. "main", "temp", or an attached database) containing the specified 4759 ** table or NULL. ^If it is NULL, then all attached databases are searched 4760 ** for the table using the same algorithm used by the database engine to 4761 ** resolve unqualified table references. 4762 ** 4763 ** ^The third and fourth parameters to this function are the table and column 4764 ** name of the desired column, respectively. Neither of these parameters 4765 ** may be NULL. 4766 ** 4767 ** ^Metadata is returned by writing to the memory locations passed as the 5th 4768 ** and subsequent parameters to this function. ^Any of these arguments may be 4769 ** NULL, in which case the corresponding element of metadata is omitted. 4770 ** 4771 ** ^(<blockquote> 4772 ** <table border="1"> 4773 ** <tr><th> Parameter <th> Output<br>Type <th> Description 4774 ** 4775 ** <tr><td> 5th <td> const char* <td> Data type 4776 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4777 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4778 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4779 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4780 ** </table> 4781 ** </blockquote>)^ 4782 ** 4783 ** ^The memory pointed to by the character pointers returned for the 4784 ** declaration type and collation sequence is valid only until the next 4785 ** call to any SQLite API function. 4786 ** 4787 ** ^If the specified table is actually a view, an [error code] is returned. 4788 ** 4789 ** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4790 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4791 ** parameters are set for the explicitly declared column. ^(If there is no 4792 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4793 ** parameters are set as follows: 4794 ** 4795 ** <pre> 4796 ** data type: "INTEGER" 4797 ** collation sequence: "BINARY" 4798 ** not null: 0 4799 ** primary key: 1 4800 ** auto increment: 0 4801 ** </pre>)^ 4802 ** 4803 ** ^(This function may load one or more schemas from database files. If an 4804 ** error occurs during this process, or if the requested table or column 4805 ** cannot be found, an [error code] is returned and an error message left 4806 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4807 ** 4808 ** ^This API is only available if the library was compiled with the 4809 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4810 */ 4811 SQLITE_API int sqlite3_table_column_metadata( 4812 sqlite3 *db, /* Connection handle */ 4813 const char *zDbName, /* Database name or NULL */ 4814 const char *zTableName, /* Table name */ 4815 const char *zColumnName, /* Column name */ 4816 char const **pzDataType, /* OUTPUT: Declared data type */ 4817 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4818 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4819 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4820 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4821 ); 4822 4823 /* 4824 ** CAPI3REF: Load An Extension 4825 ** 4826 ** ^This interface loads an SQLite extension library from the named file. 4827 ** 4828 ** ^The sqlite3_load_extension() interface attempts to load an 4829 ** SQLite extension library contained in the file zFile. 4830 ** 4831 ** ^The entry point is zProc. 4832 ** ^zProc may be 0, in which case the name of the entry point 4833 ** defaults to "sqlite3_extension_init". 4834 ** ^The sqlite3_load_extension() interface returns 4835 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4836 ** ^If an error occurs and pzErrMsg is not 0, then the 4837 ** [sqlite3_load_extension()] interface shall attempt to 4838 ** fill *pzErrMsg with error message text stored in memory 4839 ** obtained from [sqlite3_malloc()]. The calling function 4840 ** should free this memory by calling [sqlite3_free()]. 4841 ** 4842 ** ^Extension loading must be enabled using 4843 ** [sqlite3_enable_load_extension()] prior to calling this API, 4844 ** otherwise an error will be returned. 4845 ** 4846 ** See also the [load_extension() SQL function]. 4847 */ 4848 SQLITE_API int sqlite3_load_extension( 4849 sqlite3 *db, /* Load the extension into this database connection */ 4850 const char *zFile, /* Name of the shared library containing extension */ 4851 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4852 char **pzErrMsg /* Put error message here if not 0 */ 4853 ); 4854 4855 /* 4856 ** CAPI3REF: Enable Or Disable Extension Loading 4857 ** 4858 ** ^So as not to open security holes in older applications that are 4859 ** unprepared to deal with extension loading, and as a means of disabling 4860 ** extension loading while evaluating user-entered SQL, the following API 4861 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4862 ** 4863 ** ^Extension loading is off by default. See ticket #1863. 4864 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1 4865 ** to turn extension loading on and call it with onoff==0 to turn 4866 ** it back off again. 4867 */ 4868 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4869 4870 /* 4871 ** CAPI3REF: Automatically Load Statically Linked Extensions 4872 ** 4873 ** ^This interface causes the xEntryPoint() function to be invoked for 4874 ** each new [database connection] that is created. The idea here is that 4875 ** xEntryPoint() is the entry point for a statically linked SQLite extension 4876 ** that is to be automatically loaded into all new database connections. 4877 ** 4878 ** ^(Even though the function prototype shows that xEntryPoint() takes 4879 ** no arguments and returns void, SQLite invokes xEntryPoint() with three 4880 ** arguments and expects and integer result as if the signature of the 4881 ** entry point where as follows: 4882 ** 4883 ** <blockquote><pre> 4884 ** int xEntryPoint( 4885 ** sqlite3 *db, 4886 ** const char **pzErrMsg, 4887 ** const struct sqlite3_api_routines *pThunk 4888 ** ); 4889 ** </pre></blockquote>)^ 4890 ** 4891 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 4892 ** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 4893 ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 4894 ** is NULL before calling the xEntryPoint(). ^SQLite will invoke 4895 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 4896 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 4897 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 4898 ** 4899 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 4900 ** on the list of automatic extensions is a harmless no-op. ^No entry point 4901 ** will be called more than once for each database connection that is opened. 4902 ** 4903 ** See also: [sqlite3_reset_auto_extension()]. 4904 */ 4905 SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4906 4907 /* 4908 ** CAPI3REF: Reset Automatic Extension Loading 4909 ** 4910 ** ^This interface disables all automatic extensions previously 4911 ** registered using [sqlite3_auto_extension()]. 4912 */ 4913 SQLITE_API void sqlite3_reset_auto_extension(void); 4914 4915 /* 4916 ** The interface to the virtual-table mechanism is currently considered 4917 ** to be experimental. The interface might change in incompatible ways. 4918 ** If this is a problem for you, do not use the interface at this time. 4919 ** 4920 ** When the virtual-table mechanism stabilizes, we will declare the 4921 ** interface fixed, support it indefinitely, and remove this comment. 4922 */ 4923 4924 /* 4925 ** Structures used by the virtual table interface 4926 */ 4927 typedef struct sqlite3_vtab sqlite3_vtab; 4928 typedef struct sqlite3_index_info sqlite3_index_info; 4929 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4930 typedef struct sqlite3_module sqlite3_module; 4931 4932 /* 4933 ** CAPI3REF: Virtual Table Object 4934 ** KEYWORDS: sqlite3_module {virtual table module} 4935 ** 4936 ** This structure, sometimes called a "virtual table module", 4937 ** defines the implementation of a [virtual tables]. 4938 ** This structure consists mostly of methods for the module. 4939 ** 4940 ** ^A virtual table module is created by filling in a persistent 4941 ** instance of this structure and passing a pointer to that instance 4942 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4943 ** ^The registration remains valid until it is replaced by a different 4944 ** module or until the [database connection] closes. The content 4945 ** of this structure must not change while it is registered with 4946 ** any database connection. 4947 */ 4948 struct sqlite3_module { 4949 int iVersion; 4950 int (*xCreate)(sqlite3*, void *pAux, 4951 int argc, const char *const*argv, 4952 sqlite3_vtab **ppVTab, char**); 4953 int (*xConnect)(sqlite3*, void *pAux, 4954 int argc, const char *const*argv, 4955 sqlite3_vtab **ppVTab, char**); 4956 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4957 int (*xDisconnect)(sqlite3_vtab *pVTab); 4958 int (*xDestroy)(sqlite3_vtab *pVTab); 4959 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4960 int (*xClose)(sqlite3_vtab_cursor*); 4961 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4962 int argc, sqlite3_value **argv); 4963 int (*xNext)(sqlite3_vtab_cursor*); 4964 int (*xEof)(sqlite3_vtab_cursor*); 4965 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4966 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4967 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4968 int (*xBegin)(sqlite3_vtab *pVTab); 4969 int (*xSync)(sqlite3_vtab *pVTab); 4970 int (*xCommit)(sqlite3_vtab *pVTab); 4971 int (*xRollback)(sqlite3_vtab *pVTab); 4972 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4973 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4974 void **ppArg); 4975 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4976 /* The methods above are in version 1 of the sqlite_module object. Those 4977 ** below are for version 2 and greater. */ 4978 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 4979 int (*xRelease)(sqlite3_vtab *pVTab, int); 4980 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 4981 }; 4982 4983 /* 4984 ** CAPI3REF: Virtual Table Indexing Information 4985 ** KEYWORDS: sqlite3_index_info 4986 ** 4987 ** The sqlite3_index_info structure and its substructures is used as part 4988 ** of the [virtual table] interface to 4989 ** pass information into and receive the reply from the [xBestIndex] 4990 ** method of a [virtual table module]. The fields under **Inputs** are the 4991 ** inputs to xBestIndex and are read-only. xBestIndex inserts its 4992 ** results into the **Outputs** fields. 4993 ** 4994 ** ^(The aConstraint[] array records WHERE clause constraints of the form: 4995 ** 4996 ** <blockquote>column OP expr</blockquote> 4997 ** 4998 ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 4999 ** stored in aConstraint[].op using one of the 5000 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 5001 ** ^(The index of the column is stored in 5002 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5003 ** expr on the right-hand side can be evaluated (and thus the constraint 5004 ** is usable) and false if it cannot.)^ 5005 ** 5006 ** ^The optimizer automatically inverts terms of the form "expr OP column" 5007 ** and makes other simplifications to the WHERE clause in an attempt to 5008 ** get as many WHERE clause terms into the form shown above as possible. 5009 ** ^The aConstraint[] array only reports WHERE clause terms that are 5010 ** relevant to the particular virtual table being queried. 5011 ** 5012 ** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5013 ** ^Each term of aOrderBy records a column of the ORDER BY clause. 5014 ** 5015 ** The [xBestIndex] method must fill aConstraintUsage[] with information 5016 ** about what parameters to pass to xFilter. ^If argvIndex>0 then 5017 ** the right-hand side of the corresponding aConstraint[] is evaluated 5018 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5019 ** is true, then the constraint is assumed to be fully handled by the 5020 ** virtual table and is not checked again by SQLite.)^ 5021 ** 5022 ** ^The idxNum and idxPtr values are recorded and passed into the 5023 ** [xFilter] method. 5024 ** ^[sqlite3_free()] is used to free idxPtr if and only if 5025 ** needToFreeIdxPtr is true. 5026 ** 5027 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5028 ** the correct order to satisfy the ORDER BY clause so that no separate 5029 ** sorting step is required. 5030 ** 5031 ** ^The estimatedCost value is an estimate of the cost of doing the 5032 ** particular lookup. A full scan of a table with N entries should have 5033 ** a cost of N. A binary search of a table of N entries should have a 5034 ** cost of approximately log(N). 5035 */ 5036 struct sqlite3_index_info { 5037 /* Inputs */ 5038 int nConstraint; /* Number of entries in aConstraint */ 5039 struct sqlite3_index_constraint { 5040 int iColumn; /* Column on left-hand side of constraint */ 5041 unsigned char op; /* Constraint operator */ 5042 unsigned char usable; /* True if this constraint is usable */ 5043 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5044 } *aConstraint; /* Table of WHERE clause constraints */ 5045 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5046 struct sqlite3_index_orderby { 5047 int iColumn; /* Column number */ 5048 unsigned char desc; /* True for DESC. False for ASC. */ 5049 } *aOrderBy; /* The ORDER BY clause */ 5050 /* Outputs */ 5051 struct sqlite3_index_constraint_usage { 5052 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5053 unsigned char omit; /* Do not code a test for this constraint */ 5054 } *aConstraintUsage; 5055 int idxNum; /* Number used to identify the index */ 5056 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5057 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5058 int orderByConsumed; /* True if output is already ordered */ 5059 double estimatedCost; /* Estimated cost of using this index */ 5060 }; 5061 5062 /* 5063 ** CAPI3REF: Virtual Table Constraint Operator Codes 5064 ** 5065 ** These macros defined the allowed values for the 5066 ** [sqlite3_index_info].aConstraint[].op field. Each value represents 5067 ** an operator that is part of a constraint term in the wHERE clause of 5068 ** a query that uses a [virtual table]. 5069 */ 5070 #define SQLITE_INDEX_CONSTRAINT_EQ 2 5071 #define SQLITE_INDEX_CONSTRAINT_GT 4 5072 #define SQLITE_INDEX_CONSTRAINT_LE 8 5073 #define SQLITE_INDEX_CONSTRAINT_LT 16 5074 #define SQLITE_INDEX_CONSTRAINT_GE 32 5075 #define SQLITE_INDEX_CONSTRAINT_MATCH 64 5076 5077 /* 5078 ** CAPI3REF: Register A Virtual Table Implementation 5079 ** 5080 ** ^These routines are used to register a new [virtual table module] name. 5081 ** ^Module names must be registered before 5082 ** creating a new [virtual table] using the module and before using a 5083 ** preexisting [virtual table] for the module. 5084 ** 5085 ** ^The module name is registered on the [database connection] specified 5086 ** by the first parameter. ^The name of the module is given by the 5087 ** second parameter. ^The third parameter is a pointer to 5088 ** the implementation of the [virtual table module]. ^The fourth 5089 ** parameter is an arbitrary client data pointer that is passed through 5090 ** into the [xCreate] and [xConnect] methods of the virtual table module 5091 ** when a new virtual table is be being created or reinitialized. 5092 ** 5093 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which 5094 ** is a pointer to a destructor for the pClientData. ^SQLite will 5095 ** invoke the destructor function (if it is not NULL) when SQLite 5096 ** no longer needs the pClientData pointer. ^The destructor will also 5097 ** be invoked if the call to sqlite3_create_module_v2() fails. 5098 ** ^The sqlite3_create_module() 5099 ** interface is equivalent to sqlite3_create_module_v2() with a NULL 5100 ** destructor. 5101 */ 5102 SQLITE_API int sqlite3_create_module( 5103 sqlite3 *db, /* SQLite connection to register module with */ 5104 const char *zName, /* Name of the module */ 5105 const sqlite3_module *p, /* Methods for the module */ 5106 void *pClientData /* Client data for xCreate/xConnect */ 5107 ); 5108 SQLITE_API int sqlite3_create_module_v2( 5109 sqlite3 *db, /* SQLite connection to register module with */ 5110 const char *zName, /* Name of the module */ 5111 const sqlite3_module *p, /* Methods for the module */ 5112 void *pClientData, /* Client data for xCreate/xConnect */ 5113 void(*xDestroy)(void*) /* Module destructor function */ 5114 ); 5115 5116 /* 5117 ** CAPI3REF: Virtual Table Instance Object 5118 ** KEYWORDS: sqlite3_vtab 5119 ** 5120 ** Every [virtual table module] implementation uses a subclass 5121 ** of this object to describe a particular instance 5122 ** of the [virtual table]. Each subclass will 5123 ** be tailored to the specific needs of the module implementation. 5124 ** The purpose of this superclass is to define certain fields that are 5125 ** common to all module implementations. 5126 ** 5127 ** ^Virtual tables methods can set an error message by assigning a 5128 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 5129 ** take care that any prior string is freed by a call to [sqlite3_free()] 5130 ** prior to assigning a new string to zErrMsg. ^After the error message 5131 ** is delivered up to the client application, the string will be automatically 5132 ** freed by sqlite3_free() and the zErrMsg field will be zeroed. 5133 */ 5134 struct sqlite3_vtab { 5135 const sqlite3_module *pModule; /* The module for this virtual table */ 5136 int nRef; /* NO LONGER USED */ 5137 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 5138 /* Virtual table implementations will typically add additional fields */ 5139 }; 5140 5141 /* 5142 ** CAPI3REF: Virtual Table Cursor Object 5143 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 5144 ** 5145 ** Every [virtual table module] implementation uses a subclass of the 5146 ** following structure to describe cursors that point into the 5147 ** [virtual table] and are used 5148 ** to loop through the virtual table. Cursors are created using the 5149 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 5150 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used 5151 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 5152 ** of the module. Each module implementation will define 5153 ** the content of a cursor structure to suit its own needs. 5154 ** 5155 ** This superclass exists in order to define fields of the cursor that 5156 ** are common to all implementations. 5157 */ 5158 struct sqlite3_vtab_cursor { 5159 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 5160 /* Virtual table implementations will typically add additional fields */ 5161 }; 5162 5163 /* 5164 ** CAPI3REF: Declare The Schema Of A Virtual Table 5165 ** 5166 ** ^The [xCreate] and [xConnect] methods of a 5167 ** [virtual table module] call this interface 5168 ** to declare the format (the names and datatypes of the columns) of 5169 ** the virtual tables they implement. 5170 */ 5171 SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 5172 5173 /* 5174 ** CAPI3REF: Overload A Function For A Virtual Table 5175 ** 5176 ** ^(Virtual tables can provide alternative implementations of functions 5177 ** using the [xFindFunction] method of the [virtual table module]. 5178 ** But global versions of those functions 5179 ** must exist in order to be overloaded.)^ 5180 ** 5181 ** ^(This API makes sure a global version of a function with a particular 5182 ** name and number of parameters exists. If no such function exists 5183 ** before this API is called, a new function is created.)^ ^The implementation 5184 ** of the new function always causes an exception to be thrown. So 5185 ** the new function is not good for anything by itself. Its only 5186 ** purpose is to be a placeholder function that can be overloaded 5187 ** by a [virtual table]. 5188 */ 5189 SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5190 5191 /* 5192 ** The interface to the virtual-table mechanism defined above (back up 5193 ** to a comment remarkably similar to this one) is currently considered 5194 ** to be experimental. The interface might change in incompatible ways. 5195 ** If this is a problem for you, do not use the interface at this time. 5196 ** 5197 ** When the virtual-table mechanism stabilizes, we will declare the 5198 ** interface fixed, support it indefinitely, and remove this comment. 5199 */ 5200 5201 /* 5202 ** CAPI3REF: A Handle To An Open BLOB 5203 ** KEYWORDS: {BLOB handle} {BLOB handles} 5204 ** 5205 ** An instance of this object represents an open BLOB on which 5206 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5207 ** ^Objects of this type are created by [sqlite3_blob_open()] 5208 ** and destroyed by [sqlite3_blob_close()]. 5209 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5210 ** can be used to read or write small subsections of the BLOB. 5211 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5212 */ 5213 typedef struct sqlite3_blob sqlite3_blob; 5214 5215 /* 5216 ** CAPI3REF: Open A BLOB For Incremental I/O 5217 ** 5218 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5219 ** in row iRow, column zColumn, table zTable in database zDb; 5220 ** in other words, the same BLOB that would be selected by: 5221 ** 5222 ** <pre> 5223 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5224 ** </pre>)^ 5225 ** 5226 ** ^If the flags parameter is non-zero, then the BLOB is opened for read 5227 ** and write access. ^If it is zero, the BLOB is opened for read access. 5228 ** ^It is not possible to open a column that is part of an index or primary 5229 ** key for writing. ^If [foreign key constraints] are enabled, it is 5230 ** not possible to open a column that is part of a [child key] for writing. 5231 ** 5232 ** ^Note that the database name is not the filename that contains 5233 ** the database but rather the symbolic name of the database that 5234 ** appears after the AS keyword when the database is connected using [ATTACH]. 5235 ** ^For the main database file, the database name is "main". 5236 ** ^For TEMP tables, the database name is "temp". 5237 ** 5238 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 5239 ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 5240 ** to be a null pointer.)^ 5241 ** ^This function sets the [database connection] error code and message 5242 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 5243 ** functions. ^Note that the *ppBlob variable is always initialized in a 5244 ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 5245 ** regardless of the success or failure of this routine. 5246 ** 5247 ** ^(If the row that a BLOB handle points to is modified by an 5248 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5249 ** then the BLOB handle is marked as "expired". 5250 ** This is true if any column of the row is changed, even a column 5251 ** other than the one the BLOB handle is open on.)^ 5252 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5253 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5254 ** ^(Changes written into a BLOB prior to the BLOB expiring are not 5255 ** rolled back by the expiration of the BLOB. Such changes will eventually 5256 ** commit if the transaction continues to completion.)^ 5257 ** 5258 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5259 ** the opened blob. ^The size of a blob may not be changed by this 5260 ** interface. Use the [UPDATE] SQL command to change the size of a 5261 ** blob. 5262 ** 5263 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5264 ** and the built-in [zeroblob] SQL function can be used, if desired, 5265 ** to create an empty, zero-filled blob in which to read or write using 5266 ** this interface. 5267 ** 5268 ** To avoid a resource leak, every open [BLOB handle] should eventually 5269 ** be released by a call to [sqlite3_blob_close()]. 5270 */ 5271 SQLITE_API int sqlite3_blob_open( 5272 sqlite3*, 5273 const char *zDb, 5274 const char *zTable, 5275 const char *zColumn, 5276 sqlite3_int64 iRow, 5277 int flags, 5278 sqlite3_blob **ppBlob 5279 ); 5280 5281 /* 5282 ** CAPI3REF: Move a BLOB Handle to a New Row 5283 ** 5284 ** ^This function is used to move an existing blob handle so that it points 5285 ** to a different row of the same database table. ^The new row is identified 5286 ** by the rowid value passed as the second argument. Only the row can be 5287 ** changed. ^The database, table and column on which the blob handle is open 5288 ** remain the same. Moving an existing blob handle to a new row can be 5289 ** faster than closing the existing handle and opening a new one. 5290 ** 5291 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5292 ** it must exist and there must be either a blob or text value stored in 5293 ** the nominated column.)^ ^If the new row is not present in the table, or if 5294 ** it does not contain a blob or text value, or if another error occurs, an 5295 ** SQLite error code is returned and the blob handle is considered aborted. 5296 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5297 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5298 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5299 ** always returns zero. 5300 ** 5301 ** ^This function sets the database handle error code and message. 5302 */ 5303 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5304 5305 /* 5306 ** CAPI3REF: Close A BLOB Handle 5307 ** 5308 ** ^Closes an open [BLOB handle]. 5309 ** 5310 ** ^Closing a BLOB shall cause the current transaction to commit 5311 ** if there are no other BLOBs, no pending prepared statements, and the 5312 ** database connection is in [autocommit mode]. 5313 ** ^If any writes were made to the BLOB, they might be held in cache 5314 ** until the close operation if they will fit. 5315 ** 5316 ** ^(Closing the BLOB often forces the changes 5317 ** out to disk and so if any I/O errors occur, they will likely occur 5318 ** at the time when the BLOB is closed. Any errors that occur during 5319 ** closing are reported as a non-zero return value.)^ 5320 ** 5321 ** ^(The BLOB is closed unconditionally. Even if this routine returns 5322 ** an error code, the BLOB is still closed.)^ 5323 ** 5324 ** ^Calling this routine with a null pointer (such as would be returned 5325 ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 5326 */ 5327 SQLITE_API int sqlite3_blob_close(sqlite3_blob *); 5328 5329 /* 5330 ** CAPI3REF: Return The Size Of An Open BLOB 5331 ** 5332 ** ^Returns the size in bytes of the BLOB accessible via the 5333 ** successfully opened [BLOB handle] in its only argument. ^The 5334 ** incremental blob I/O routines can only read or overwriting existing 5335 ** blob content; they cannot change the size of a blob. 5336 ** 5337 ** This routine only works on a [BLOB handle] which has been created 5338 ** by a prior successful call to [sqlite3_blob_open()] and which has not 5339 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5340 ** to this routine results in undefined and probably undesirable behavior. 5341 */ 5342 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *); 5343 5344 /* 5345 ** CAPI3REF: Read Data From A BLOB Incrementally 5346 ** 5347 ** ^(This function is used to read data from an open [BLOB handle] into a 5348 ** caller-supplied buffer. N bytes of data are copied into buffer Z 5349 ** from the open BLOB, starting at offset iOffset.)^ 5350 ** 5351 ** ^If offset iOffset is less than N bytes from the end of the BLOB, 5352 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 5353 ** less than zero, [SQLITE_ERROR] is returned and no data is read. 5354 ** ^The size of the blob (and hence the maximum value of N+iOffset) 5355 ** can be determined using the [sqlite3_blob_bytes()] interface. 5356 ** 5357 ** ^An attempt to read from an expired [BLOB handle] fails with an 5358 ** error code of [SQLITE_ABORT]. 5359 ** 5360 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 5361 ** Otherwise, an [error code] or an [extended error code] is returned.)^ 5362 ** 5363 ** This routine only works on a [BLOB handle] which has been created 5364 ** by a prior successful call to [sqlite3_blob_open()] and which has not 5365 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5366 ** to this routine results in undefined and probably undesirable behavior. 5367 ** 5368 ** See also: [sqlite3_blob_write()]. 5369 */ 5370 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 5371 5372 /* 5373 ** CAPI3REF: Write Data Into A BLOB Incrementally 5374 ** 5375 ** ^This function is used to write data into an open [BLOB handle] from a 5376 ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 5377 ** into the open BLOB, starting at offset iOffset. 5378 ** 5379 ** ^If the [BLOB handle] passed as the first argument was not opened for 5380 ** writing (the flags parameter to [sqlite3_blob_open()] was zero), 5381 ** this function returns [SQLITE_READONLY]. 5382 ** 5383 ** ^This function may only modify the contents of the BLOB; it is 5384 ** not possible to increase the size of a BLOB using this API. 5385 ** ^If offset iOffset is less than N bytes from the end of the BLOB, 5386 ** [SQLITE_ERROR] is returned and no data is written. ^If N is 5387 ** less than zero [SQLITE_ERROR] is returned and no data is written. 5388 ** The size of the BLOB (and hence the maximum value of N+iOffset) 5389 ** can be determined using the [sqlite3_blob_bytes()] interface. 5390 ** 5391 ** ^An attempt to write to an expired [BLOB handle] fails with an 5392 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 5393 ** before the [BLOB handle] expired are not rolled back by the 5394 ** expiration of the handle, though of course those changes might 5395 ** have been overwritten by the statement that expired the BLOB handle 5396 ** or by other independent statements. 5397 ** 5398 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 5399 ** Otherwise, an [error code] or an [extended error code] is returned.)^ 5400 ** 5401 ** This routine only works on a [BLOB handle] which has been created 5402 ** by a prior successful call to [sqlite3_blob_open()] and which has not 5403 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5404 ** to this routine results in undefined and probably undesirable behavior. 5405 ** 5406 ** See also: [sqlite3_blob_read()]. 5407 */ 5408 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 5409 5410 /* 5411 ** CAPI3REF: Virtual File System Objects 5412 ** 5413 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object 5414 ** that SQLite uses to interact 5415 ** with the underlying operating system. Most SQLite builds come with a 5416 ** single default VFS that is appropriate for the host computer. 5417 ** New VFSes can be registered and existing VFSes can be unregistered. 5418 ** The following interfaces are provided. 5419 ** 5420 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 5421 ** ^Names are case sensitive. 5422 ** ^Names are zero-terminated UTF-8 strings. 5423 ** ^If there is no match, a NULL pointer is returned. 5424 ** ^If zVfsName is NULL then the default VFS is returned. 5425 ** 5426 ** ^New VFSes are registered with sqlite3_vfs_register(). 5427 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 5428 ** ^The same VFS can be registered multiple times without injury. 5429 ** ^To make an existing VFS into the default VFS, register it again 5430 ** with the makeDflt flag set. If two different VFSes with the 5431 ** same name are registered, the behavior is undefined. If a 5432 ** VFS is registered with a name that is NULL or an empty string, 5433 ** then the behavior is undefined. 5434 ** 5435 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 5436 ** ^(If the default VFS is unregistered, another VFS is chosen as 5437 ** the default. The choice for the new VFS is arbitrary.)^ 5438 */ 5439 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 5440 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 5441 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*); 5442 5443 /* 5444 ** CAPI3REF: Mutexes 5445 ** 5446 ** The SQLite core uses these routines for thread 5447 ** synchronization. Though they are intended for internal 5448 ** use by SQLite, code that links against SQLite is 5449 ** permitted to use any of these routines. 5450 ** 5451 ** The SQLite source code contains multiple implementations 5452 ** of these mutex routines. An appropriate implementation 5453 ** is selected automatically at compile-time. ^(The following 5454 ** implementations are available in the SQLite core: 5455 ** 5456 ** <ul> 5457 ** <li> SQLITE_MUTEX_OS2 5458 ** <li> SQLITE_MUTEX_PTHREADS 5459 ** <li> SQLITE_MUTEX_W32 5460 ** <li> SQLITE_MUTEX_NOOP 5461 ** </ul>)^ 5462 ** 5463 ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 5464 ** that does no real locking and is appropriate for use in 5465 ** a single-threaded application. ^The SQLITE_MUTEX_OS2, 5466 ** SQLITE_MUTEX_PTHREADS, and SQLITE_MUTEX_W32 implementations 5467 ** are appropriate for use on OS/2, Unix, and Windows. 5468 ** 5469 ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 5470 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 5471 ** implementation is included with the library. In this case the 5472 ** application must supply a custom mutex implementation using the 5473 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 5474 ** before calling sqlite3_initialize() or any other public sqlite3_ 5475 ** function that calls sqlite3_initialize().)^ 5476 ** 5477 ** ^The sqlite3_mutex_alloc() routine allocates a new 5478 ** mutex and returns a pointer to it. ^If it returns NULL 5479 ** that means that a mutex could not be allocated. ^SQLite 5480 ** will unwind its stack and return an error. ^(The argument 5481 ** to sqlite3_mutex_alloc() is one of these integer constants: 5482 ** 5483 ** <ul> 5484 ** <li> SQLITE_MUTEX_FAST 5485 ** <li> SQLITE_MUTEX_RECURSIVE 5486 ** <li> SQLITE_MUTEX_STATIC_MASTER 5487 ** <li> SQLITE_MUTEX_STATIC_MEM 5488 ** <li> SQLITE_MUTEX_STATIC_MEM2 5489 ** <li> SQLITE_MUTEX_STATIC_PRNG 5490 ** <li> SQLITE_MUTEX_STATIC_LRU 5491 ** <li> SQLITE_MUTEX_STATIC_LRU2 5492 ** </ul>)^ 5493 ** 5494 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 5495 ** cause sqlite3_mutex_alloc() to create 5496 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 5497 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 5498 ** The mutex implementation does not need to make a distinction 5499 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 5500 ** not want to. ^SQLite will only request a recursive mutex in 5501 ** cases where it really needs one. ^If a faster non-recursive mutex 5502 ** implementation is available on the host platform, the mutex subsystem 5503 ** might return such a mutex in response to SQLITE_MUTEX_FAST. 5504 ** 5505 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 5506 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 5507 ** a pointer to a static preexisting mutex. ^Six static mutexes are 5508 ** used by the current version of SQLite. Future versions of SQLite 5509 ** may add additional static mutexes. Static mutexes are for internal 5510 ** use by SQLite only. Applications that use SQLite mutexes should 5511 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 5512 ** SQLITE_MUTEX_RECURSIVE. 5513 ** 5514 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 5515 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 5516 ** returns a different mutex on every call. ^But for the static 5517 ** mutex types, the same mutex is returned on every call that has 5518 ** the same type number. 5519 ** 5520 ** ^The sqlite3_mutex_free() routine deallocates a previously 5521 ** allocated dynamic mutex. ^SQLite is careful to deallocate every 5522 ** dynamic mutex that it allocates. The dynamic mutexes must not be in 5523 ** use when they are deallocated. Attempting to deallocate a static 5524 ** mutex results in undefined behavior. ^SQLite never deallocates 5525 ** a static mutex. 5526 ** 5527 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 5528 ** to enter a mutex. ^If another thread is already within the mutex, 5529 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 5530 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 5531 ** upon successful entry. ^(Mutexes created using 5532 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 5533 ** In such cases the, 5534 ** mutex must be exited an equal number of times before another thread 5535 ** can enter.)^ ^(If the same thread tries to enter any other 5536 ** kind of mutex more than once, the behavior is undefined. 5537 ** SQLite will never exhibit 5538 ** such behavior in its own use of mutexes.)^ 5539 ** 5540 ** ^(Some systems (for example, Windows 95) do not support the operation 5541 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 5542 ** will always return SQLITE_BUSY. The SQLite core only ever uses 5543 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 5544 ** 5545 ** ^The sqlite3_mutex_leave() routine exits a mutex that was 5546 ** previously entered by the same thread. ^(The behavior 5547 ** is undefined if the mutex is not currently entered by the 5548 ** calling thread or is not currently allocated. SQLite will 5549 ** never do either.)^ 5550 ** 5551 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 5552 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines 5553 ** behave as no-ops. 5554 ** 5555 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 5556 */ 5557 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int); 5558 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*); 5559 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*); 5560 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*); 5561 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*); 5562 5563 /* 5564 ** CAPI3REF: Mutex Methods Object 5565 ** 5566 ** An instance of this structure defines the low-level routines 5567 ** used to allocate and use mutexes. 5568 ** 5569 ** Usually, the default mutex implementations provided by SQLite are 5570 ** sufficient, however the user has the option of substituting a custom 5571 ** implementation for specialized deployments or systems for which SQLite 5572 ** does not provide a suitable implementation. In this case, the user 5573 ** creates and populates an instance of this structure to pass 5574 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 5575 ** Additionally, an instance of this structure can be used as an 5576 ** output variable when querying the system for the current mutex 5577 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 5578 ** 5579 ** ^The xMutexInit method defined by this structure is invoked as 5580 ** part of system initialization by the sqlite3_initialize() function. 5581 ** ^The xMutexInit routine is called by SQLite exactly once for each 5582 ** effective call to [sqlite3_initialize()]. 5583 ** 5584 ** ^The xMutexEnd method defined by this structure is invoked as 5585 ** part of system shutdown by the sqlite3_shutdown() function. The 5586 ** implementation of this method is expected to release all outstanding 5587 ** resources obtained by the mutex methods implementation, especially 5588 ** those obtained by the xMutexInit method. ^The xMutexEnd() 5589 ** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 5590 ** 5591 ** ^(The remaining seven methods defined by this structure (xMutexAlloc, 5592 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 5593 ** xMutexNotheld) implement the following interfaces (respectively): 5594 ** 5595 ** <ul> 5596 ** <li> [sqlite3_mutex_alloc()] </li> 5597 ** <li> [sqlite3_mutex_free()] </li> 5598 ** <li> [sqlite3_mutex_enter()] </li> 5599 ** <li> [sqlite3_mutex_try()] </li> 5600 ** <li> [sqlite3_mutex_leave()] </li> 5601 ** <li> [sqlite3_mutex_held()] </li> 5602 ** <li> [sqlite3_mutex_notheld()] </li> 5603 ** </ul>)^ 5604 ** 5605 ** The only difference is that the public sqlite3_XXX functions enumerated 5606 ** above silently ignore any invocations that pass a NULL pointer instead 5607 ** of a valid mutex handle. The implementations of the methods defined 5608 ** by this structure are not required to handle this case, the results 5609 ** of passing a NULL pointer instead of a valid mutex handle are undefined 5610 ** (i.e. it is acceptable to provide an implementation that segfaults if 5611 ** it is passed a NULL pointer). 5612 ** 5613 ** The xMutexInit() method must be threadsafe. ^It must be harmless to 5614 ** invoke xMutexInit() multiple times within the same process and without 5615 ** intervening calls to xMutexEnd(). Second and subsequent calls to 5616 ** xMutexInit() must be no-ops. 5617 ** 5618 ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 5619 ** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 5620 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 5621 ** memory allocation for a fast or recursive mutex. 5622 ** 5623 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 5624 ** called, but only if the prior call to xMutexInit returned SQLITE_OK. 5625 ** If xMutexInit fails in any way, it is expected to clean up after itself 5626 ** prior to returning. 5627 */ 5628 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 5629 struct sqlite3_mutex_methods { 5630 int (*xMutexInit)(void); 5631 int (*xMutexEnd)(void); 5632 sqlite3_mutex *(*xMutexAlloc)(int); 5633 void (*xMutexFree)(sqlite3_mutex *); 5634 void (*xMutexEnter)(sqlite3_mutex *); 5635 int (*xMutexTry)(sqlite3_mutex *); 5636 void (*xMutexLeave)(sqlite3_mutex *); 5637 int (*xMutexHeld)(sqlite3_mutex *); 5638 int (*xMutexNotheld)(sqlite3_mutex *); 5639 }; 5640 5641 /* 5642 ** CAPI3REF: Mutex Verification Routines 5643 ** 5644 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 5645 ** are intended for use inside assert() statements. ^The SQLite core 5646 ** never uses these routines except inside an assert() and applications 5647 ** are advised to follow the lead of the core. ^The SQLite core only 5648 ** provides implementations for these routines when it is compiled 5649 ** with the SQLITE_DEBUG flag. ^External mutex implementations 5650 ** are only required to provide these routines if SQLITE_DEBUG is 5651 ** defined and if NDEBUG is not defined. 5652 ** 5653 ** ^These routines should return true if the mutex in their argument 5654 ** is held or not held, respectively, by the calling thread. 5655 ** 5656 ** ^The implementation is not required to provide versions of these 5657 ** routines that actually work. If the implementation does not provide working 5658 ** versions of these routines, it should at least provide stubs that always 5659 ** return true so that one does not get spurious assertion failures. 5660 ** 5661 ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 5662 ** the routine should return 1. This seems counter-intuitive since 5663 ** clearly the mutex cannot be held if it does not exist. But 5664 ** the reason the mutex does not exist is because the build is not 5665 ** using mutexes. And we do not want the assert() containing the 5666 ** call to sqlite3_mutex_held() to fail, so a non-zero return is 5667 ** the appropriate thing to do. ^The sqlite3_mutex_notheld() 5668 ** interface should also return 1 when given a NULL pointer. 5669 */ 5670 #ifndef NDEBUG 5671 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*); 5672 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*); 5673 #endif 5674 5675 /* 5676 ** CAPI3REF: Mutex Types 5677 ** 5678 ** The [sqlite3_mutex_alloc()] interface takes a single argument 5679 ** which is one of these integer constants. 5680 ** 5681 ** The set of static mutexes may change from one SQLite release to the 5682 ** next. Applications that override the built-in mutex logic must be 5683 ** prepared to accommodate additional static mutexes. 5684 */ 5685 #define SQLITE_MUTEX_FAST 0 5686 #define SQLITE_MUTEX_RECURSIVE 1 5687 #define SQLITE_MUTEX_STATIC_MASTER 2 5688 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 5689 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 5690 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 5691 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 5692 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 5693 #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 5694 #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 5695 5696 /* 5697 ** CAPI3REF: Retrieve the mutex for a database connection 5698 ** 5699 ** ^This interface returns a pointer the [sqlite3_mutex] object that 5700 ** serializes access to the [database connection] given in the argument 5701 ** when the [threading mode] is Serialized. 5702 ** ^If the [threading mode] is Single-thread or Multi-thread then this 5703 ** routine returns a NULL pointer. 5704 */ 5705 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 5706 5707 /* 5708 ** CAPI3REF: Low-Level Control Of Database Files 5709 ** 5710 ** ^The [sqlite3_file_control()] interface makes a direct call to the 5711 ** xFileControl method for the [sqlite3_io_methods] object associated 5712 ** with a particular database identified by the second argument. ^The 5713 ** name of the database is "main" for the main database or "temp" for the 5714 ** TEMP database, or the name that appears after the AS keyword for 5715 ** databases that are added using the [ATTACH] SQL command. 5716 ** ^A NULL pointer can be used in place of "main" to refer to the 5717 ** main database file. 5718 ** ^The third and fourth parameters to this routine 5719 ** are passed directly through to the second and third parameters of 5720 ** the xFileControl method. ^The return value of the xFileControl 5721 ** method becomes the return value of this routine. 5722 ** 5723 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 5724 ** a pointer to the underlying [sqlite3_file] object to be written into 5725 ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 5726 ** case is a short-circuit path which does not actually invoke the 5727 ** underlying sqlite3_io_methods.xFileControl method. 5728 ** 5729 ** ^If the second parameter (zDbName) does not match the name of any 5730 ** open database file, then SQLITE_ERROR is returned. ^This error 5731 ** code is not remembered and will not be recalled by [sqlite3_errcode()] 5732 ** or [sqlite3_errmsg()]. The underlying xFileControl method might 5733 ** also return SQLITE_ERROR. There is no way to distinguish between 5734 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5735 ** xFileControl method. 5736 ** 5737 ** See also: [SQLITE_FCNTL_LOCKSTATE] 5738 */ 5739 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5740 5741 /* 5742 ** CAPI3REF: Testing Interface 5743 ** 5744 ** ^The sqlite3_test_control() interface is used to read out internal 5745 ** state of SQLite and to inject faults into SQLite for testing 5746 ** purposes. ^The first parameter is an operation code that determines 5747 ** the number, meaning, and operation of all subsequent parameters. 5748 ** 5749 ** This interface is not for use by applications. It exists solely 5750 ** for verifying the correct operation of the SQLite library. Depending 5751 ** on how the SQLite library is compiled, this interface might not exist. 5752 ** 5753 ** The details of the operation codes, their meanings, the parameters 5754 ** they take, and what they do are all subject to change without notice. 5755 ** Unlike most of the SQLite API, this function is not guaranteed to 5756 ** operate consistently from one release to the next. 5757 */ 5758 SQLITE_API int sqlite3_test_control(int op, ...); 5759 5760 /* 5761 ** CAPI3REF: Testing Interface Operation Codes 5762 ** 5763 ** These constants are the valid operation code parameters used 5764 ** as the first argument to [sqlite3_test_control()]. 5765 ** 5766 ** These parameters and their meanings are subject to change 5767 ** without notice. These values are for testing purposes only. 5768 ** Applications should not use any of these parameters or the 5769 ** [sqlite3_test_control()] interface. 5770 */ 5771 #define SQLITE_TESTCTRL_FIRST 5 5772 #define SQLITE_TESTCTRL_PRNG_SAVE 5 5773 #define SQLITE_TESTCTRL_PRNG_RESTORE 6 5774 #define SQLITE_TESTCTRL_PRNG_RESET 7 5775 #define SQLITE_TESTCTRL_BITVEC_TEST 8 5776 #define SQLITE_TESTCTRL_FAULT_INSTALL 9 5777 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5778 #define SQLITE_TESTCTRL_PENDING_BYTE 11 5779 #define SQLITE_TESTCTRL_ASSERT 12 5780 #define SQLITE_TESTCTRL_ALWAYS 13 5781 #define SQLITE_TESTCTRL_RESERVE 14 5782 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15 5783 #define SQLITE_TESTCTRL_ISKEYWORD 16 5784 #define SQLITE_TESTCTRL_SCRATCHMALLOC 17 5785 #define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 5786 #define SQLITE_TESTCTRL_EXPLAIN_STMT 19 5787 #define SQLITE_TESTCTRL_LAST 19 5788 5789 /* 5790 ** CAPI3REF: SQLite Runtime Status 5791 ** 5792 ** ^This interface is used to retrieve runtime status information 5793 ** about the performance of SQLite, and optionally to reset various 5794 ** highwater marks. ^The first argument is an integer code for 5795 ** the specific parameter to measure. ^(Recognized integer codes 5796 ** are of the form [status parameters | SQLITE_STATUS_...].)^ 5797 ** ^The current value of the parameter is returned into *pCurrent. 5798 ** ^The highest recorded value is returned in *pHighwater. ^If the 5799 ** resetFlag is true, then the highest record value is reset after 5800 ** *pHighwater is written. ^(Some parameters do not record the highest 5801 ** value. For those parameters 5802 ** nothing is written into *pHighwater and the resetFlag is ignored.)^ 5803 ** ^(Other parameters record only the highwater mark and not the current 5804 ** value. For these latter parameters nothing is written into *pCurrent.)^ 5805 ** 5806 ** ^The sqlite3_status() routine returns SQLITE_OK on success and a 5807 ** non-zero [error code] on failure. 5808 ** 5809 ** This routine is threadsafe but is not atomic. This routine can be 5810 ** called while other threads are running the same or different SQLite 5811 ** interfaces. However the values returned in *pCurrent and 5812 ** *pHighwater reflect the status of SQLite at different points in time 5813 ** and it is possible that another thread might change the parameter 5814 ** in between the times when *pCurrent and *pHighwater are written. 5815 ** 5816 ** See also: [sqlite3_db_status()] 5817 */ 5818 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 5819 5820 5821 /* 5822 ** CAPI3REF: Status Parameters 5823 ** KEYWORDS: {status parameters} 5824 ** 5825 ** These integer constants designate various run-time status parameters 5826 ** that can be returned by [sqlite3_status()]. 5827 ** 5828 ** <dl> 5829 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 5830 ** <dd>This parameter is the current amount of memory checked out 5831 ** using [sqlite3_malloc()], either directly or indirectly. The 5832 ** figure includes calls made to [sqlite3_malloc()] by the application 5833 ** and internal memory usage by the SQLite library. Scratch memory 5834 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 5835 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 5836 ** this parameter. The amount returned is the sum of the allocation 5837 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 5838 ** 5839 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 5840 ** <dd>This parameter records the largest memory allocation request 5841 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 5842 ** internal equivalents). Only the value returned in the 5843 ** *pHighwater parameter to [sqlite3_status()] is of interest. 5844 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 5845 ** 5846 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 5847 ** <dd>This parameter records the number of separate memory allocations 5848 ** currently checked out.</dd>)^ 5849 ** 5850 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 5851 ** <dd>This parameter returns the number of pages used out of the 5852 ** [pagecache memory allocator] that was configured using 5853 ** [SQLITE_CONFIG_PAGECACHE]. The 5854 ** value returned is in pages, not in bytes.</dd>)^ 5855 ** 5856 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 5857 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5858 ** <dd>This parameter returns the number of bytes of page cache 5859 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 5860 ** buffer and where forced to overflow to [sqlite3_malloc()]. The 5861 ** returned value includes allocations that overflowed because they 5862 ** where too large (they were larger than the "sz" parameter to 5863 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 5864 ** no space was left in the page cache.</dd>)^ 5865 ** 5866 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 5867 ** <dd>This parameter records the largest memory allocation request 5868 ** handed to [pagecache memory allocator]. Only the value returned in the 5869 ** *pHighwater parameter to [sqlite3_status()] is of interest. 5870 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 5871 ** 5872 ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 5873 ** <dd>This parameter returns the number of allocations used out of the 5874 ** [scratch memory allocator] configured using 5875 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5876 ** in bytes. Since a single thread may only have one scratch allocation 5877 ** outstanding at time, this parameter also reports the number of threads 5878 ** using scratch memory at the same time.</dd>)^ 5879 ** 5880 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5881 ** <dd>This parameter returns the number of bytes of scratch memory 5882 ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 5883 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5884 ** returned include overflows because the requested allocation was too 5885 ** larger (that is, because the requested allocation was larger than the 5886 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5887 ** slots were available. 5888 ** </dd>)^ 5889 ** 5890 ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5891 ** <dd>This parameter records the largest memory allocation request 5892 ** handed to [scratch memory allocator]. Only the value returned in the 5893 ** *pHighwater parameter to [sqlite3_status()] is of interest. 5894 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 5895 ** 5896 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 5897 ** <dd>This parameter records the deepest parser stack. It is only 5898 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 5899 ** </dl> 5900 ** 5901 ** New status parameters may be added from time to time. 5902 */ 5903 #define SQLITE_STATUS_MEMORY_USED 0 5904 #define SQLITE_STATUS_PAGECACHE_USED 1 5905 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5906 #define SQLITE_STATUS_SCRATCH_USED 3 5907 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5908 #define SQLITE_STATUS_MALLOC_SIZE 5 5909 #define SQLITE_STATUS_PARSER_STACK 6 5910 #define SQLITE_STATUS_PAGECACHE_SIZE 7 5911 #define SQLITE_STATUS_SCRATCH_SIZE 8 5912 #define SQLITE_STATUS_MALLOC_COUNT 9 5913 5914 /* 5915 ** CAPI3REF: Database Connection Status 5916 ** 5917 ** ^This interface is used to retrieve runtime status information 5918 ** about a single [database connection]. ^The first argument is the 5919 ** database connection object to be interrogated. ^The second argument 5920 ** is an integer constant, taken from the set of 5921 ** [SQLITE_DBSTATUS options], that 5922 ** determines the parameter to interrogate. The set of 5923 ** [SQLITE_DBSTATUS options] is likely 5924 ** to grow in future releases of SQLite. 5925 ** 5926 ** ^The current value of the requested parameter is written into *pCur 5927 ** and the highest instantaneous value is written into *pHiwtr. ^If 5928 ** the resetFlg is true, then the highest instantaneous value is 5929 ** reset back down to the current value. 5930 ** 5931 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 5932 ** non-zero [error code] on failure. 5933 ** 5934 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5935 */ 5936 SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5937 5938 /* 5939 ** CAPI3REF: Status Parameters for database connections 5940 ** KEYWORDS: {SQLITE_DBSTATUS options} 5941 ** 5942 ** These constants are the available integer "verbs" that can be passed as 5943 ** the second argument to the [sqlite3_db_status()] interface. 5944 ** 5945 ** New verbs may be added in future releases of SQLite. Existing verbs 5946 ** might be discontinued. Applications should check the return code from 5947 ** [sqlite3_db_status()] to make sure that the call worked. 5948 ** The [sqlite3_db_status()] interface will return a non-zero error code 5949 ** if a discontinued or unsupported verb is invoked. 5950 ** 5951 ** <dl> 5952 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5953 ** <dd>This parameter returns the number of lookaside memory slots currently 5954 ** checked out.</dd>)^ 5955 ** 5956 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 5957 ** <dd>This parameter returns the number malloc attempts that were 5958 ** satisfied using lookaside memory. Only the high-water value is meaningful; 5959 ** the current value is always zero.)^ 5960 ** 5961 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 5962 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 5963 ** <dd>This parameter returns the number malloc attempts that might have 5964 ** been satisfied using lookaside memory but failed due to the amount of 5965 ** memory requested being larger than the lookaside slot size. 5966 ** Only the high-water value is meaningful; 5967 ** the current value is always zero.)^ 5968 ** 5969 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 5970 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 5971 ** <dd>This parameter returns the number malloc attempts that might have 5972 ** been satisfied using lookaside memory but failed due to all lookaside 5973 ** memory already being in use. 5974 ** Only the high-water value is meaningful; 5975 ** the current value is always zero.)^ 5976 ** 5977 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 5978 ** <dd>This parameter returns the approximate number of of bytes of heap 5979 ** memory used by all pager caches associated with the database connection.)^ 5980 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 5981 ** 5982 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 5983 ** <dd>This parameter returns the approximate number of of bytes of heap 5984 ** memory used to store the schema for all databases associated 5985 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 5986 ** ^The full amount of memory used by the schemas is reported, even if the 5987 ** schema memory is shared with other database connections due to 5988 ** [shared cache mode] being enabled. 5989 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 5990 ** 5991 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 5992 ** <dd>This parameter returns the approximate number of of bytes of heap 5993 ** and lookaside memory used by all prepared statements associated with 5994 ** the database connection.)^ 5995 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 5996 ** </dd> 5997 ** 5998 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 5999 ** <dd>This parameter returns the number of pager cache hits that have 6000 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 6001 ** is always 0. 6002 ** </dd> 6003 ** 6004 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6005 ** <dd>This parameter returns the number of pager cache misses that have 6006 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6007 ** is always 0. 6008 ** </dd> 6009 ** </dl> 6010 */ 6011 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6012 #define SQLITE_DBSTATUS_CACHE_USED 1 6013 #define SQLITE_DBSTATUS_SCHEMA_USED 2 6014 #define SQLITE_DBSTATUS_STMT_USED 3 6015 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6016 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6017 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 6018 #define SQLITE_DBSTATUS_CACHE_HIT 7 6019 #define SQLITE_DBSTATUS_CACHE_MISS 8 6020 #define SQLITE_DBSTATUS_MAX 8 /* Largest defined DBSTATUS */ 6021 6022 6023 /* 6024 ** CAPI3REF: Prepared Statement Status 6025 ** 6026 ** ^(Each prepared statement maintains various 6027 ** [SQLITE_STMTSTATUS counters] that measure the number 6028 ** of times it has performed specific operations.)^ These counters can 6029 ** be used to monitor the performance characteristics of the prepared 6030 ** statements. For example, if the number of table steps greatly exceeds 6031 ** the number of table searches or result rows, that would tend to indicate 6032 ** that the prepared statement is using a full table scan rather than 6033 ** an index. 6034 ** 6035 ** ^(This interface is used to retrieve and reset counter values from 6036 ** a [prepared statement]. The first argument is the prepared statement 6037 ** object to be interrogated. The second argument 6038 ** is an integer code for a specific [SQLITE_STMTSTATUS counter] 6039 ** to be interrogated.)^ 6040 ** ^The current value of the requested counter is returned. 6041 ** ^If the resetFlg is true, then the counter is reset to zero after this 6042 ** interface call returns. 6043 ** 6044 ** See also: [sqlite3_status()] and [sqlite3_db_status()]. 6045 */ 6046 SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 6047 6048 /* 6049 ** CAPI3REF: Status Parameters for prepared statements 6050 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 6051 ** 6052 ** These preprocessor macros define integer codes that name counter 6053 ** values associated with the [sqlite3_stmt_status()] interface. 6054 ** The meanings of the various counters are as follows: 6055 ** 6056 ** <dl> 6057 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 6058 ** <dd>^This is the number of times that SQLite has stepped forward in 6059 ** a table as part of a full table scan. Large numbers for this counter 6060 ** may indicate opportunities for performance improvement through 6061 ** careful use of indices.</dd> 6062 ** 6063 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 6064 ** <dd>^This is the number of sort operations that have occurred. 6065 ** A non-zero value in this counter may indicate an opportunity to 6066 ** improvement performance through careful use of indices.</dd> 6067 ** 6068 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 6069 ** <dd>^This is the number of rows inserted into transient indices that 6070 ** were created automatically in order to help joins run faster. 6071 ** A non-zero value in this counter may indicate an opportunity to 6072 ** improvement performance by adding permanent indices that do not 6073 ** need to be reinitialized each time the statement is run.</dd> 6074 ** </dl> 6075 */ 6076 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 6077 #define SQLITE_STMTSTATUS_SORT 2 6078 #define SQLITE_STMTSTATUS_AUTOINDEX 3 6079 6080 /* 6081 ** CAPI3REF: Custom Page Cache Object 6082 ** 6083 ** The sqlite3_pcache type is opaque. It is implemented by 6084 ** the pluggable module. The SQLite core has no knowledge of 6085 ** its size or internal structure and never deals with the 6086 ** sqlite3_pcache object except by holding and passing pointers 6087 ** to the object. 6088 ** 6089 ** See [sqlite3_pcache_methods2] for additional information. 6090 */ 6091 typedef struct sqlite3_pcache sqlite3_pcache; 6092 6093 /* 6094 ** CAPI3REF: Custom Page Cache Object 6095 ** 6096 ** The sqlite3_pcache_page object represents a single page in the 6097 ** page cache. The page cache will allocate instances of this 6098 ** object. Various methods of the page cache use pointers to instances 6099 ** of this object as parameters or as their return value. 6100 ** 6101 ** See [sqlite3_pcache_methods2] for additional information. 6102 */ 6103 typedef struct sqlite3_pcache_page sqlite3_pcache_page; 6104 struct sqlite3_pcache_page { 6105 void *pBuf; /* The content of the page */ 6106 void *pExtra; /* Extra information associated with the page */ 6107 }; 6108 6109 /* 6110 ** CAPI3REF: Application Defined Page Cache. 6111 ** KEYWORDS: {page cache} 6112 ** 6113 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 6114 ** register an alternative page cache implementation by passing in an 6115 ** instance of the sqlite3_pcache_methods2 structure.)^ 6116 ** In many applications, most of the heap memory allocated by 6117 ** SQLite is used for the page cache. 6118 ** By implementing a 6119 ** custom page cache using this API, an application can better control 6120 ** the amount of memory consumed by SQLite, the way in which 6121 ** that memory is allocated and released, and the policies used to 6122 ** determine exactly which parts of a database file are cached and for 6123 ** how long. 6124 ** 6125 ** The alternative page cache mechanism is an 6126 ** extreme measure that is only needed by the most demanding applications. 6127 ** The built-in page cache is recommended for most uses. 6128 ** 6129 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 6130 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence 6131 ** the application may discard the parameter after the call to 6132 ** [sqlite3_config()] returns.)^ 6133 ** 6134 ** [[the xInit() page cache method]] 6135 ** ^(The xInit() method is called once for each effective 6136 ** call to [sqlite3_initialize()])^ 6137 ** (usually only once during the lifetime of the process). ^(The xInit() 6138 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 6139 ** The intent of the xInit() method is to set up global data structures 6140 ** required by the custom page cache implementation. 6141 ** ^(If the xInit() method is NULL, then the 6142 ** built-in default page cache is used instead of the application defined 6143 ** page cache.)^ 6144 ** 6145 ** [[the xShutdown() page cache method]] 6146 ** ^The xShutdown() method is called by [sqlite3_shutdown()]. 6147 ** It can be used to clean up 6148 ** any outstanding resources before process shutdown, if required. 6149 ** ^The xShutdown() method may be NULL. 6150 ** 6151 ** ^SQLite automatically serializes calls to the xInit method, 6152 ** so the xInit method need not be threadsafe. ^The 6153 ** xShutdown method is only called from [sqlite3_shutdown()] so it does 6154 ** not need to be threadsafe either. All other methods must be threadsafe 6155 ** in multithreaded applications. 6156 ** 6157 ** ^SQLite will never invoke xInit() more than once without an intervening 6158 ** call to xShutdown(). 6159 ** 6160 ** [[the xCreate() page cache methods]] 6161 ** ^SQLite invokes the xCreate() method to construct a new cache instance. 6162 ** SQLite will typically create one cache instance for each open database file, 6163 ** though this is not guaranteed. ^The 6164 ** first parameter, szPage, is the size in bytes of the pages that must 6165 ** be allocated by the cache. ^szPage will always a power of two. ^The 6166 ** second parameter szExtra is a number of bytes of extra storage 6167 ** associated with each page cache entry. ^The szExtra parameter will 6168 ** a number less than 250. SQLite will use the 6169 ** extra szExtra bytes on each page to store metadata about the underlying 6170 ** database page on disk. The value passed into szExtra depends 6171 ** on the SQLite version, the target platform, and how SQLite was compiled. 6172 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being 6173 ** created will be used to cache database pages of a file stored on disk, or 6174 ** false if it is used for an in-memory database. The cache implementation 6175 ** does not have to do anything special based with the value of bPurgeable; 6176 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 6177 ** never invoke xUnpin() except to deliberately delete a page. 6178 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 6179 ** false will always have the "discard" flag set to true. 6180 ** ^Hence, a cache created with bPurgeable false will 6181 ** never contain any unpinned pages. 6182 ** 6183 ** [[the xCachesize() page cache method]] 6184 ** ^(The xCachesize() method may be called at any time by SQLite to set the 6185 ** suggested maximum cache-size (number of pages stored by) the cache 6186 ** instance passed as the first argument. This is the value configured using 6187 ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 6188 ** parameter, the implementation is not required to do anything with this 6189 ** value; it is advisory only. 6190 ** 6191 ** [[the xPagecount() page cache methods]] 6192 ** The xPagecount() method must return the number of pages currently 6193 ** stored in the cache, both pinned and unpinned. 6194 ** 6195 ** [[the xFetch() page cache methods]] 6196 ** The xFetch() method locates a page in the cache and returns a pointer to 6197 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 6198 ** The pBuf element of the returned sqlite3_pcache_page object will be a 6199 ** pointer to a buffer of szPage bytes used to store the content of a 6200 ** single database page. The pExtra element of sqlite3_pcache_page will be 6201 ** a pointer to the szExtra bytes of extra storage that SQLite has requested 6202 ** for each entry in the page cache. 6203 ** 6204 ** The page to be fetched is determined by the key. ^The minimum key value 6205 ** is 1. After it has been retrieved using xFetch, the page is considered 6206 ** to be "pinned". 6207 ** 6208 ** If the requested page is already in the page cache, then the page cache 6209 ** implementation must return a pointer to the page buffer with its content 6210 ** intact. If the requested page is not already in the cache, then the 6211 ** cache implementation should use the value of the createFlag 6212 ** parameter to help it determined what action to take: 6213 ** 6214 ** <table border=1 width=85% align=center> 6215 ** <tr><th> createFlag <th> Behaviour when page is not already in cache 6216 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6217 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6218 ** Otherwise return NULL. 6219 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6220 ** NULL if allocating a new page is effectively impossible. 6221 ** </table> 6222 ** 6223 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6224 ** will only use a createFlag of 2 after a prior call with a createFlag of 1 6225 ** failed.)^ In between the to xFetch() calls, SQLite may 6226 ** attempt to unpin one or more cache pages by spilling the content of 6227 ** pinned pages to disk and synching the operating system disk cache. 6228 ** 6229 ** [[the xUnpin() page cache method]] 6230 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6231 ** as its second argument. If the third parameter, discard, is non-zero, 6232 ** then the page must be evicted from the cache. 6233 ** ^If the discard parameter is 6234 ** zero, then the page may be discarded or retained at the discretion of 6235 ** page cache implementation. ^The page cache implementation 6236 ** may choose to evict unpinned pages at any time. 6237 ** 6238 ** The cache must not perform any reference counting. A single 6239 ** call to xUnpin() unpins the page regardless of the number of prior calls 6240 ** to xFetch(). 6241 ** 6242 ** [[the xRekey() page cache methods]] 6243 ** The xRekey() method is used to change the key value associated with the 6244 ** page passed as the second argument. If the cache 6245 ** previously contains an entry associated with newKey, it must be 6246 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6247 ** to be pinned. 6248 ** 6249 ** When SQLite calls the xTruncate() method, the cache must discard all 6250 ** existing cache entries with page numbers (keys) greater than or equal 6251 ** to the value of the iLimit parameter passed to xTruncate(). If any 6252 ** of these pages are pinned, they are implicitly unpinned, meaning that 6253 ** they can be safely discarded. 6254 ** 6255 ** [[the xDestroy() page cache method]] 6256 ** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6257 ** All resources associated with the specified cache should be freed. ^After 6258 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6259 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2 6260 ** functions. 6261 ** 6262 ** [[the xShrink() page cache method]] 6263 ** ^SQLite invokes the xShrink() method when it wants the page cache to 6264 ** free up as much of heap memory as possible. The page cache implementation 6265 ** is not obligated to free any memory, but well-behaved implementations should 6266 ** do their best. 6267 */ 6268 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 6269 struct sqlite3_pcache_methods2 { 6270 int iVersion; 6271 void *pArg; 6272 int (*xInit)(void*); 6273 void (*xShutdown)(void*); 6274 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 6275 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6276 int (*xPagecount)(sqlite3_pcache*); 6277 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6278 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 6279 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 6280 unsigned oldKey, unsigned newKey); 6281 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6282 void (*xDestroy)(sqlite3_pcache*); 6283 void (*xShrink)(sqlite3_pcache*); 6284 }; 6285 6286 /* 6287 ** This is the obsolete pcache_methods object that has now been replaced 6288 ** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 6289 ** retained in the header file for backwards compatibility only. 6290 */ 6291 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 6292 struct sqlite3_pcache_methods { 6293 void *pArg; 6294 int (*xInit)(void*); 6295 void (*xShutdown)(void*); 6296 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 6297 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6298 int (*xPagecount)(sqlite3_pcache*); 6299 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6300 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 6301 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 6302 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6303 void (*xDestroy)(sqlite3_pcache*); 6304 }; 6305 6306 6307 /* 6308 ** CAPI3REF: Online Backup Object 6309 ** 6310 ** The sqlite3_backup object records state information about an ongoing 6311 ** online backup operation. ^The sqlite3_backup object is created by 6312 ** a call to [sqlite3_backup_init()] and is destroyed by a call to 6313 ** [sqlite3_backup_finish()]. 6314 ** 6315 ** See Also: [Using the SQLite Online Backup API] 6316 */ 6317 typedef struct sqlite3_backup sqlite3_backup; 6318 6319 /* 6320 ** CAPI3REF: Online Backup API. 6321 ** 6322 ** The backup API copies the content of one database into another. 6323 ** It is useful either for creating backups of databases or 6324 ** for copying in-memory databases to or from persistent files. 6325 ** 6326 ** See Also: [Using the SQLite Online Backup API] 6327 ** 6328 ** ^SQLite holds a write transaction open on the destination database file 6329 ** for the duration of the backup operation. 6330 ** ^The source database is read-locked only while it is being read; 6331 ** it is not locked continuously for the entire backup operation. 6332 ** ^Thus, the backup may be performed on a live source database without 6333 ** preventing other database connections from 6334 ** reading or writing to the source database while the backup is underway. 6335 ** 6336 ** ^(To perform a backup operation: 6337 ** <ol> 6338 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the 6339 ** backup, 6340 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 6341 ** the data between the two databases, and finally 6342 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources 6343 ** associated with the backup operation. 6344 ** </ol>)^ 6345 ** There should be exactly one call to sqlite3_backup_finish() for each 6346 ** successful call to sqlite3_backup_init(). 6347 ** 6348 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 6349 ** 6350 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 6351 ** [database connection] associated with the destination database 6352 ** and the database name, respectively. 6353 ** ^The database name is "main" for the main database, "temp" for the 6354 ** temporary database, or the name specified after the AS keyword in 6355 ** an [ATTACH] statement for an attached database. 6356 ** ^The S and M arguments passed to 6357 ** sqlite3_backup_init(D,N,S,M) identify the [database connection] 6358 ** and database name of the source database, respectively. 6359 ** ^The source and destination [database connections] (parameters S and D) 6360 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 6361 ** an error. 6362 ** 6363 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 6364 ** returned and an error code and error message are stored in the 6365 ** destination [database connection] D. 6366 ** ^The error code and message for the failed call to sqlite3_backup_init() 6367 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 6368 ** [sqlite3_errmsg16()] functions. 6369 ** ^A successful call to sqlite3_backup_init() returns a pointer to an 6370 ** [sqlite3_backup] object. 6371 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 6372 ** sqlite3_backup_finish() functions to perform the specified backup 6373 ** operation. 6374 ** 6375 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 6376 ** 6377 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 6378 ** the source and destination databases specified by [sqlite3_backup] object B. 6379 ** ^If N is negative, all remaining source pages are copied. 6380 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 6381 ** are still more pages to be copied, then the function returns [SQLITE_OK]. 6382 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 6383 ** from source to destination, then it returns [SQLITE_DONE]. 6384 ** ^If an error occurs while running sqlite3_backup_step(B,N), 6385 ** then an [error code] is returned. ^As well as [SQLITE_OK] and 6386 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 6387 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 6388 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 6389 ** 6390 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 6391 ** <ol> 6392 ** <li> the destination database was opened read-only, or 6393 ** <li> the destination database is using write-ahead-log journaling 6394 ** and the destination and source page sizes differ, or 6395 ** <li> the destination database is an in-memory database and the 6396 ** destination and source page sizes differ. 6397 ** </ol>)^ 6398 ** 6399 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 6400 ** the [sqlite3_busy_handler | busy-handler function] 6401 ** is invoked (if one is specified). ^If the 6402 ** busy-handler returns non-zero before the lock is available, then 6403 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 6404 ** sqlite3_backup_step() can be retried later. ^If the source 6405 ** [database connection] 6406 ** is being used to write to the source database when sqlite3_backup_step() 6407 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 6408 ** case the call to sqlite3_backup_step() can be retried later on. ^(If 6409 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 6410 ** [SQLITE_READONLY] is returned, then 6411 ** there is no point in retrying the call to sqlite3_backup_step(). These 6412 ** errors are considered fatal.)^ The application must accept 6413 ** that the backup operation has failed and pass the backup operation handle 6414 ** to the sqlite3_backup_finish() to release associated resources. 6415 ** 6416 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock 6417 ** on the destination file. ^The exclusive lock is not released until either 6418 ** sqlite3_backup_finish() is called or the backup operation is complete 6419 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 6420 ** sqlite3_backup_step() obtains a [shared lock] on the source database that 6421 ** lasts for the duration of the sqlite3_backup_step() call. 6422 ** ^Because the source database is not locked between calls to 6423 ** sqlite3_backup_step(), the source database may be modified mid-way 6424 ** through the backup process. ^If the source database is modified by an 6425 ** external process or via a database connection other than the one being 6426 ** used by the backup operation, then the backup will be automatically 6427 ** restarted by the next call to sqlite3_backup_step(). ^If the source 6428 ** database is modified by the using the same database connection as is used 6429 ** by the backup operation, then the backup database is automatically 6430 ** updated at the same time. 6431 ** 6432 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 6433 ** 6434 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 6435 ** application wishes to abandon the backup operation, the application 6436 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 6437 ** ^The sqlite3_backup_finish() interfaces releases all 6438 ** resources associated with the [sqlite3_backup] object. 6439 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 6440 ** active write-transaction on the destination database is rolled back. 6441 ** The [sqlite3_backup] object is invalid 6442 ** and may not be used following a call to sqlite3_backup_finish(). 6443 ** 6444 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 6445 ** sqlite3_backup_step() errors occurred, regardless or whether or not 6446 ** sqlite3_backup_step() completed. 6447 ** ^If an out-of-memory condition or IO error occurred during any prior 6448 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 6449 ** sqlite3_backup_finish() returns the corresponding [error code]. 6450 ** 6451 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 6452 ** is not a permanent error and does not affect the return value of 6453 ** sqlite3_backup_finish(). 6454 ** 6455 ** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]] 6456 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 6457 ** 6458 ** ^Each call to sqlite3_backup_step() sets two values inside 6459 ** the [sqlite3_backup] object: the number of pages still to be backed 6460 ** up and the total number of pages in the source database file. 6461 ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 6462 ** retrieve these two values, respectively. 6463 ** 6464 ** ^The values returned by these functions are only updated by 6465 ** sqlite3_backup_step(). ^If the source database is modified during a backup 6466 ** operation, then the values are not updated to account for any extra 6467 ** pages that need to be updated or the size of the source database file 6468 ** changing. 6469 ** 6470 ** <b>Concurrent Usage of Database Handles</b> 6471 ** 6472 ** ^The source [database connection] may be used by the application for other 6473 ** purposes while a backup operation is underway or being initialized. 6474 ** ^If SQLite is compiled and configured to support threadsafe database 6475 ** connections, then the source database connection may be used concurrently 6476 ** from within other threads. 6477 ** 6478 ** However, the application must guarantee that the destination 6479 ** [database connection] is not passed to any other API (by any thread) after 6480 ** sqlite3_backup_init() is called and before the corresponding call to 6481 ** sqlite3_backup_finish(). SQLite does not currently check to see 6482 ** if the application incorrectly accesses the destination [database connection] 6483 ** and so no error code is reported, but the operations may malfunction 6484 ** nevertheless. Use of the destination database connection while a 6485 ** backup is in progress might also also cause a mutex deadlock. 6486 ** 6487 ** If running in [shared cache mode], the application must 6488 ** guarantee that the shared cache used by the destination database 6489 ** is not accessed while the backup is running. In practice this means 6490 ** that the application must guarantee that the disk file being 6491 ** backed up to is not accessed by any connection within the process, 6492 ** not just the specific connection that was passed to sqlite3_backup_init(). 6493 ** 6494 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple 6495 ** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 6496 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 6497 ** APIs are not strictly speaking threadsafe. If they are invoked at the 6498 ** same time as another thread is invoking sqlite3_backup_step() it is 6499 ** possible that they return invalid values. 6500 */ 6501 SQLITE_API sqlite3_backup *sqlite3_backup_init( 6502 sqlite3 *pDest, /* Destination database handle */ 6503 const char *zDestName, /* Destination database name */ 6504 sqlite3 *pSource, /* Source database handle */ 6505 const char *zSourceName /* Source database name */ 6506 ); 6507 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage); 6508 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p); 6509 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p); 6510 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p); 6511 6512 /* 6513 ** CAPI3REF: Unlock Notification 6514 ** 6515 ** ^When running in shared-cache mode, a database operation may fail with 6516 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 6517 ** individual tables within the shared-cache cannot be obtained. See 6518 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 6519 ** ^This API may be used to register a callback that SQLite will invoke 6520 ** when the connection currently holding the required lock relinquishes it. 6521 ** ^This API is only available if the library was compiled with the 6522 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 6523 ** 6524 ** See Also: [Using the SQLite Unlock Notification Feature]. 6525 ** 6526 ** ^Shared-cache locks are released when a database connection concludes 6527 ** its current transaction, either by committing it or rolling it back. 6528 ** 6529 ** ^When a connection (known as the blocked connection) fails to obtain a 6530 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 6531 ** identity of the database connection (the blocking connection) that 6532 ** has locked the required resource is stored internally. ^After an 6533 ** application receives an SQLITE_LOCKED error, it may call the 6534 ** sqlite3_unlock_notify() method with the blocked connection handle as 6535 ** the first argument to register for a callback that will be invoked 6536 ** when the blocking connections current transaction is concluded. ^The 6537 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 6538 ** call that concludes the blocking connections transaction. 6539 ** 6540 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 6541 ** there is a chance that the blocking connection will have already 6542 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 6543 ** If this happens, then the specified callback is invoked immediately, 6544 ** from within the call to sqlite3_unlock_notify().)^ 6545 ** 6546 ** ^If the blocked connection is attempting to obtain a write-lock on a 6547 ** shared-cache table, and more than one other connection currently holds 6548 ** a read-lock on the same table, then SQLite arbitrarily selects one of 6549 ** the other connections to use as the blocking connection. 6550 ** 6551 ** ^(There may be at most one unlock-notify callback registered by a 6552 ** blocked connection. If sqlite3_unlock_notify() is called when the 6553 ** blocked connection already has a registered unlock-notify callback, 6554 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 6555 ** called with a NULL pointer as its second argument, then any existing 6556 ** unlock-notify callback is canceled. ^The blocked connections 6557 ** unlock-notify callback may also be canceled by closing the blocked 6558 ** connection using [sqlite3_close()]. 6559 ** 6560 ** The unlock-notify callback is not reentrant. If an application invokes 6561 ** any sqlite3_xxx API functions from within an unlock-notify callback, a 6562 ** crash or deadlock may be the result. 6563 ** 6564 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 6565 ** returns SQLITE_OK. 6566 ** 6567 ** <b>Callback Invocation Details</b> 6568 ** 6569 ** When an unlock-notify callback is registered, the application provides a 6570 ** single void* pointer that is passed to the callback when it is invoked. 6571 ** However, the signature of the callback function allows SQLite to pass 6572 ** it an array of void* context pointers. The first argument passed to 6573 ** an unlock-notify callback is a pointer to an array of void* pointers, 6574 ** and the second is the number of entries in the array. 6575 ** 6576 ** When a blocking connections transaction is concluded, there may be 6577 ** more than one blocked connection that has registered for an unlock-notify 6578 ** callback. ^If two or more such blocked connections have specified the 6579 ** same callback function, then instead of invoking the callback function 6580 ** multiple times, it is invoked once with the set of void* context pointers 6581 ** specified by the blocked connections bundled together into an array. 6582 ** This gives the application an opportunity to prioritize any actions 6583 ** related to the set of unblocked database connections. 6584 ** 6585 ** <b>Deadlock Detection</b> 6586 ** 6587 ** Assuming that after registering for an unlock-notify callback a 6588 ** database waits for the callback to be issued before taking any further 6589 ** action (a reasonable assumption), then using this API may cause the 6590 ** application to deadlock. For example, if connection X is waiting for 6591 ** connection Y's transaction to be concluded, and similarly connection 6592 ** Y is waiting on connection X's transaction, then neither connection 6593 ** will proceed and the system may remain deadlocked indefinitely. 6594 ** 6595 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 6596 ** detection. ^If a given call to sqlite3_unlock_notify() would put the 6597 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no 6598 ** unlock-notify callback is registered. The system is said to be in 6599 ** a deadlocked state if connection A has registered for an unlock-notify 6600 ** callback on the conclusion of connection B's transaction, and connection 6601 ** B has itself registered for an unlock-notify callback when connection 6602 ** A's transaction is concluded. ^Indirect deadlock is also detected, so 6603 ** the system is also considered to be deadlocked if connection B has 6604 ** registered for an unlock-notify callback on the conclusion of connection 6605 ** C's transaction, where connection C is waiting on connection A. ^Any 6606 ** number of levels of indirection are allowed. 6607 ** 6608 ** <b>The "DROP TABLE" Exception</b> 6609 ** 6610 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 6611 ** always appropriate to call sqlite3_unlock_notify(). There is however, 6612 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 6613 ** SQLite checks if there are any currently executing SELECT statements 6614 ** that belong to the same connection. If there are, SQLITE_LOCKED is 6615 ** returned. In this case there is no "blocking connection", so invoking 6616 ** sqlite3_unlock_notify() results in the unlock-notify callback being 6617 ** invoked immediately. If the application then re-attempts the "DROP TABLE" 6618 ** or "DROP INDEX" query, an infinite loop might be the result. 6619 ** 6620 ** One way around this problem is to check the extended error code returned 6621 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the 6622 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 6623 ** the special "DROP TABLE/INDEX" case, the extended error code is just 6624 ** SQLITE_LOCKED.)^ 6625 */ 6626 SQLITE_API int sqlite3_unlock_notify( 6627 sqlite3 *pBlocked, /* Waiting connection */ 6628 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 6629 void *pNotifyArg /* Argument to pass to xNotify */ 6630 ); 6631 6632 6633 /* 6634 ** CAPI3REF: String Comparison 6635 ** 6636 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 6637 ** and extensions to compare the contents of two buffers containing UTF-8 6638 ** strings in a case-independent fashion, using the same definition of "case 6639 ** independence" that SQLite uses internally when comparing identifiers. 6640 */ 6641 SQLITE_API int sqlite3_stricmp(const char *, const char *); 6642 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int); 6643 6644 /* 6645 ** CAPI3REF: Error Logging Interface 6646 ** 6647 ** ^The [sqlite3_log()] interface writes a message into the error log 6648 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 6649 ** ^If logging is enabled, the zFormat string and subsequent arguments are 6650 ** used with [sqlite3_snprintf()] to generate the final output string. 6651 ** 6652 ** The sqlite3_log() interface is intended for use by extensions such as 6653 ** virtual tables, collating functions, and SQL functions. While there is 6654 ** nothing to prevent an application from calling sqlite3_log(), doing so 6655 ** is considered bad form. 6656 ** 6657 ** The zFormat string must not be NULL. 6658 ** 6659 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine 6660 ** will not use dynamically allocated memory. The log message is stored in 6661 ** a fixed-length buffer on the stack. If the log message is longer than 6662 ** a few hundred characters, it will be truncated to the length of the 6663 ** buffer. 6664 */ 6665 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...); 6666 6667 /* 6668 ** CAPI3REF: Write-Ahead Log Commit Hook 6669 ** 6670 ** ^The [sqlite3_wal_hook()] function is used to register a callback that 6671 ** will be invoked each time a database connection commits data to a 6672 ** [write-ahead log] (i.e. whenever a transaction is committed in 6673 ** [journal_mode | journal_mode=WAL mode]). 6674 ** 6675 ** ^The callback is invoked by SQLite after the commit has taken place and 6676 ** the associated write-lock on the database released, so the implementation 6677 ** may read, write or [checkpoint] the database as required. 6678 ** 6679 ** ^The first parameter passed to the callback function when it is invoked 6680 ** is a copy of the third parameter passed to sqlite3_wal_hook() when 6681 ** registering the callback. ^The second is a copy of the database handle. 6682 ** ^The third parameter is the name of the database that was written to - 6683 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 6684 ** is the number of pages currently in the write-ahead log file, 6685 ** including those that were just committed. 6686 ** 6687 ** The callback function should normally return [SQLITE_OK]. ^If an error 6688 ** code is returned, that error will propagate back up through the 6689 ** SQLite code base to cause the statement that provoked the callback 6690 ** to report an error, though the commit will have still occurred. If the 6691 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 6692 ** that does not correspond to any valid SQLite error code, the results 6693 ** are undefined. 6694 ** 6695 ** A single database handle may have at most a single write-ahead log callback 6696 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 6697 ** previously registered write-ahead log callback. ^Note that the 6698 ** [sqlite3_wal_autocheckpoint()] interface and the 6699 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 6700 ** those overwrite any prior [sqlite3_wal_hook()] settings. 6701 */ 6702 SQLITE_API void *sqlite3_wal_hook( 6703 sqlite3*, 6704 int(*)(void *,sqlite3*,const char*,int), 6705 void* 6706 ); 6707 6708 /* 6709 ** CAPI3REF: Configure an auto-checkpoint 6710 ** 6711 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 6712 ** [sqlite3_wal_hook()] that causes any database on [database connection] D 6713 ** to automatically [checkpoint] 6714 ** after committing a transaction if there are N or 6715 ** more frames in the [write-ahead log] file. ^Passing zero or 6716 ** a negative value as the nFrame parameter disables automatic 6717 ** checkpoints entirely. 6718 ** 6719 ** ^The callback registered by this function replaces any existing callback 6720 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 6721 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 6722 ** configured by this function. 6723 ** 6724 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 6725 ** from SQL. 6726 ** 6727 ** ^Every new [database connection] defaults to having the auto-checkpoint 6728 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 6729 ** pages. The use of this interface 6730 ** is only necessary if the default setting is found to be suboptimal 6731 ** for a particular application. 6732 */ 6733 SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 6734 6735 /* 6736 ** CAPI3REF: Checkpoint a database 6737 ** 6738 ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 6739 ** on [database connection] D to be [checkpointed]. ^If X is NULL or an 6740 ** empty string, then a checkpoint is run on all databases of 6741 ** connection D. ^If the database connection D is not in 6742 ** [WAL | write-ahead log mode] then this interface is a harmless no-op. 6743 ** 6744 ** ^The [wal_checkpoint pragma] can be used to invoke this interface 6745 ** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 6746 ** [wal_autocheckpoint pragma] can be used to cause this interface to be 6747 ** run whenever the WAL reaches a certain size threshold. 6748 ** 6749 ** See also: [sqlite3_wal_checkpoint_v2()] 6750 */ 6751 SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 6752 6753 /* 6754 ** CAPI3REF: Checkpoint a database 6755 ** 6756 ** Run a checkpoint operation on WAL database zDb attached to database 6757 ** handle db. The specific operation is determined by the value of the 6758 ** eMode parameter: 6759 ** 6760 ** <dl> 6761 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 6762 ** Checkpoint as many frames as possible without waiting for any database 6763 ** readers or writers to finish. Sync the db file if all frames in the log 6764 ** are checkpointed. This mode is the same as calling 6765 ** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked. 6766 ** 6767 ** <dt>SQLITE_CHECKPOINT_FULL<dd> 6768 ** This mode blocks (calls the busy-handler callback) until there is no 6769 ** database writer and all readers are reading from the most recent database 6770 ** snapshot. It then checkpoints all frames in the log file and syncs the 6771 ** database file. This call blocks database writers while it is running, 6772 ** but not database readers. 6773 ** 6774 ** <dt>SQLITE_CHECKPOINT_RESTART<dd> 6775 ** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after 6776 ** checkpointing the log file it blocks (calls the busy-handler callback) 6777 ** until all readers are reading from the database file only. This ensures 6778 ** that the next client to write to the database file restarts the log file 6779 ** from the beginning. This call blocks database writers while it is running, 6780 ** but not database readers. 6781 ** </dl> 6782 ** 6783 ** If pnLog is not NULL, then *pnLog is set to the total number of frames in 6784 ** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to 6785 ** the total number of checkpointed frames (including any that were already 6786 ** checkpointed when this function is called). *pnLog and *pnCkpt may be 6787 ** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK. 6788 ** If no values are available because of an error, they are both set to -1 6789 ** before returning to communicate this to the caller. 6790 ** 6791 ** All calls obtain an exclusive "checkpoint" lock on the database file. If 6792 ** any other process is running a checkpoint operation at the same time, the 6793 ** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a 6794 ** busy-handler configured, it will not be invoked in this case. 6795 ** 6796 ** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive 6797 ** "writer" lock on the database file. If the writer lock cannot be obtained 6798 ** immediately, and a busy-handler is configured, it is invoked and the writer 6799 ** lock retried until either the busy-handler returns 0 or the lock is 6800 ** successfully obtained. The busy-handler is also invoked while waiting for 6801 ** database readers as described above. If the busy-handler returns 0 before 6802 ** the writer lock is obtained or while waiting for database readers, the 6803 ** checkpoint operation proceeds from that point in the same way as 6804 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 6805 ** without blocking any further. SQLITE_BUSY is returned in this case. 6806 ** 6807 ** If parameter zDb is NULL or points to a zero length string, then the 6808 ** specified operation is attempted on all WAL databases. In this case the 6809 ** values written to output parameters *pnLog and *pnCkpt are undefined. If 6810 ** an SQLITE_BUSY error is encountered when processing one or more of the 6811 ** attached WAL databases, the operation is still attempted on any remaining 6812 ** attached databases and SQLITE_BUSY is returned to the caller. If any other 6813 ** error occurs while processing an attached database, processing is abandoned 6814 ** and the error code returned to the caller immediately. If no error 6815 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached 6816 ** databases, SQLITE_OK is returned. 6817 ** 6818 ** If database zDb is the name of an attached database that is not in WAL 6819 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If 6820 ** zDb is not NULL (or a zero length string) and is not the name of any 6821 ** attached database, SQLITE_ERROR is returned to the caller. 6822 */ 6823 SQLITE_API int sqlite3_wal_checkpoint_v2( 6824 sqlite3 *db, /* Database handle */ 6825 const char *zDb, /* Name of attached database (or NULL) */ 6826 int eMode, /* SQLITE_CHECKPOINT_* value */ 6827 int *pnLog, /* OUT: Size of WAL log in frames */ 6828 int *pnCkpt /* OUT: Total number of frames checkpointed */ 6829 ); 6830 6831 /* 6832 ** CAPI3REF: Checkpoint operation parameters 6833 ** 6834 ** These constants can be used as the 3rd parameter to 6835 ** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()] 6836 ** documentation for additional information about the meaning and use of 6837 ** each of these values. 6838 */ 6839 #define SQLITE_CHECKPOINT_PASSIVE 0 6840 #define SQLITE_CHECKPOINT_FULL 1 6841 #define SQLITE_CHECKPOINT_RESTART 2 6842 6843 /* 6844 ** CAPI3REF: Virtual Table Interface Configuration 6845 ** 6846 ** This function may be called by either the [xConnect] or [xCreate] method 6847 ** of a [virtual table] implementation to configure 6848 ** various facets of the virtual table interface. 6849 ** 6850 ** If this interface is invoked outside the context of an xConnect or 6851 ** xCreate virtual table method then the behavior is undefined. 6852 ** 6853 ** At present, there is only one option that may be configured using 6854 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 6855 ** may be added in the future. 6856 */ 6857 SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...); 6858 6859 /* 6860 ** CAPI3REF: Virtual Table Configuration Options 6861 ** 6862 ** These macros define the various options to the 6863 ** [sqlite3_vtab_config()] interface that [virtual table] implementations 6864 ** can use to customize and optimize their behavior. 6865 ** 6866 ** <dl> 6867 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 6868 ** <dd>Calls of the form 6869 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 6870 ** where X is an integer. If X is zero, then the [virtual table] whose 6871 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 6872 ** support constraints. In this configuration (which is the default) if 6873 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 6874 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 6875 ** specified as part of the users SQL statement, regardless of the actual 6876 ** ON CONFLICT mode specified. 6877 ** 6878 ** If X is non-zero, then the virtual table implementation guarantees 6879 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 6880 ** any modifications to internal or persistent data structures have been made. 6881 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 6882 ** is able to roll back a statement or database transaction, and abandon 6883 ** or continue processing the current SQL statement as appropriate. 6884 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 6885 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 6886 ** had been ABORT. 6887 ** 6888 ** Virtual table implementations that are required to handle OR REPLACE 6889 ** must do so within the [xUpdate] method. If a call to the 6890 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON 6891 ** CONFLICT policy is REPLACE, the virtual table implementation should 6892 ** silently replace the appropriate rows within the xUpdate callback and 6893 ** return SQLITE_OK. Or, if this is not possible, it may return 6894 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 6895 ** constraint handling. 6896 ** </dl> 6897 */ 6898 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 6899 6900 /* 6901 ** CAPI3REF: Determine The Virtual Table Conflict Policy 6902 ** 6903 ** This function may only be called from within a call to the [xUpdate] method 6904 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 6905 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 6906 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 6907 ** of the SQL statement that triggered the call to the [xUpdate] method of the 6908 ** [virtual table]. 6909 */ 6910 SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *); 6911 6912 /* 6913 ** CAPI3REF: Conflict resolution modes 6914 ** 6915 ** These constants are returned by [sqlite3_vtab_on_conflict()] to 6916 ** inform a [virtual table] implementation what the [ON CONFLICT] mode 6917 ** is for the SQL statement being evaluated. 6918 ** 6919 ** Note that the [SQLITE_IGNORE] constant is also used as a potential 6920 ** return value from the [sqlite3_set_authorizer()] callback and that 6921 ** [SQLITE_ABORT] is also a [result code]. 6922 */ 6923 #define SQLITE_ROLLBACK 1 6924 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 6925 #define SQLITE_FAIL 3 6926 /* #define SQLITE_ABORT 4 // Also an error code */ 6927 #define SQLITE_REPLACE 5 6928 6929 6930 6931 /* 6932 ** Undo the hack that converts floating point types to integer for 6933 ** builds on processors without floating point support. 6934 */ 6935 #ifdef SQLITE_OMIT_FLOATING_POINT 6936 # undef double 6937 #endif 6938 6939 #ifdef __cplusplus 6940 } /* End of the 'extern "C"' block */ 6941 #endif 6942 #endif 6943 6944 /* 6945 ** 2010 August 30 6946 ** 6947 ** The author disclaims copyright to this source code. In place of 6948 ** a legal notice, here is a blessing: 6949 ** 6950 ** May you do good and not evil. 6951 ** May you find forgiveness for yourself and forgive others. 6952 ** May you share freely, never taking more than you give. 6953 ** 6954 ************************************************************************* 6955 */ 6956 6957 #ifndef _SQLITE3RTREE_H_ 6958 #define _SQLITE3RTREE_H_ 6959 6960 6961 #ifdef __cplusplus 6962 extern "C" { 6963 #endif 6964 6965 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry; 6966 6967 /* 6968 ** Register a geometry callback named zGeom that can be used as part of an 6969 ** R-Tree geometry query as follows: 6970 ** 6971 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...) 6972 */ 6973 SQLITE_API int sqlite3_rtree_geometry_callback( 6974 sqlite3 *db, 6975 const char *zGeom, 6976 int (*xGeom)(sqlite3_rtree_geometry *, int nCoord, double *aCoord, int *pRes), 6977 void *pContext 6978 ); 6979 6980 6981 /* 6982 ** A pointer to a structure of the following type is passed as the first 6983 ** argument to callbacks registered using rtree_geometry_callback(). 6984 */ 6985 struct sqlite3_rtree_geometry { 6986 void *pContext; /* Copy of pContext passed to s_r_g_c() */ 6987 int nParam; /* Size of array aParam[] */ 6988 double *aParam; /* Parameters passed to SQL geom function */ 6989 void *pUser; /* Callback implementation user data */ 6990 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */ 6991 }; 6992 6993 6994 #ifdef __cplusplus 6995 } /* end of the 'extern "C"' block */ 6996 #endif 6997 6998 #endif /* ifndef _SQLITE3RTREE_H_ */ 6999 7000