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 evalutes 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 "3.6.22" 111 #define SQLITE_VERSION_NUMBER 3006022 112 #define SQLITE_SOURCE_ID "2010-03-22 23:55:10 82dd61fccff3e4c77e060e5734cd4b4e2eeb7c32" 113 114 /* 115 ** CAPI3REF: Run-Time Library Version Numbers 116 ** KEYWORDS: sqlite3_version 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 a pointer 139 ** to a string constant whose value is the same as the [SQLITE_SOURCE_ID] 140 ** 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: Test To See If The Library Is Threadsafe 151 ** 152 ** ^The sqlite3_threadsafe() function returns zero if and only if 153 ** SQLite was compiled mutexing code omitted due to the 154 ** [SQLITE_THREADSAFE] compile-time option being set to 0. 155 ** 156 ** SQLite can be compiled with or without mutexes. When 157 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 158 ** are enabled and SQLite is threadsafe. When the 159 ** [SQLITE_THREADSAFE] macro is 0, 160 ** the mutexes are omitted. Without the mutexes, it is not safe 161 ** to use SQLite concurrently from more than one thread. 162 ** 163 ** Enabling mutexes incurs a measurable performance penalty. 164 ** So if speed is of utmost importance, it makes sense to disable 165 ** the mutexes. But for maximum safety, mutexes should be enabled. 166 ** ^The default behavior is for mutexes to be enabled. 167 ** 168 ** This interface can be used by an application to make sure that the 169 ** version of SQLite that it is linking against was compiled with 170 ** the desired setting of the [SQLITE_THREADSAFE] macro. 171 ** 172 ** This interface only reports on the compile-time mutex setting 173 ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 174 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 175 ** can be fully or partially disabled using a call to [sqlite3_config()] 176 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 177 ** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the 178 ** sqlite3_threadsafe() function shows only the compile-time setting of 179 ** thread safety, not any run-time changes to that setting made by 180 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 181 ** is unchanged by calls to sqlite3_config().)^ 182 ** 183 ** See the [threading mode] documentation for additional information. 184 */ 185 SQLITE_API int sqlite3_threadsafe(void); 186 187 /* 188 ** CAPI3REF: Database Connection Handle 189 ** KEYWORDS: {database connection} {database connections} 190 ** 191 ** Each open SQLite database is represented by a pointer to an instance of 192 ** the opaque structure named "sqlite3". It is useful to think of an sqlite3 193 ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 194 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 195 ** is its destructor. There are many other interfaces (such as 196 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 197 ** [sqlite3_busy_timeout()] to name but three) that are methods on an 198 ** sqlite3 object. 199 */ 200 typedef struct sqlite3 sqlite3; 201 202 /* 203 ** CAPI3REF: 64-Bit Integer Types 204 ** KEYWORDS: sqlite_int64 sqlite_uint64 205 ** 206 ** Because there is no cross-platform way to specify 64-bit integer types 207 ** SQLite includes typedefs for 64-bit signed and unsigned integers. 208 ** 209 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 210 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards 211 ** compatibility only. 212 ** 213 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values 214 ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 215 ** sqlite3_uint64 and sqlite_uint64 types can store integer values 216 ** between 0 and +18446744073709551615 inclusive. 217 */ 218 #ifdef SQLITE_INT64_TYPE 219 typedef SQLITE_INT64_TYPE sqlite_int64; 220 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 221 #elif defined(_MSC_VER) || defined(__BORLANDC__) 222 typedef __int64 sqlite_int64; 223 typedef unsigned __int64 sqlite_uint64; 224 #else 225 typedef long long int sqlite_int64; 226 typedef unsigned long long int sqlite_uint64; 227 #endif 228 typedef sqlite_int64 sqlite3_int64; 229 typedef sqlite_uint64 sqlite3_uint64; 230 231 /* 232 ** If compiling for a processor that lacks floating point support, 233 ** substitute integer for floating-point. 234 */ 235 #ifdef SQLITE_OMIT_FLOATING_POINT 236 # define double sqlite3_int64 237 #endif 238 239 /* 240 ** CAPI3REF: Closing A Database Connection 241 ** 242 ** ^The sqlite3_close() routine is the destructor for the [sqlite3] object. 243 ** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is 244 ** successfullly destroyed and all associated resources are deallocated. 245 ** 246 ** Applications must [sqlite3_finalize | finalize] all [prepared statements] 247 ** and [sqlite3_blob_close | close] all [BLOB handles] associated with 248 ** the [sqlite3] object prior to attempting to close the object. ^If 249 ** sqlite3_close() is called on a [database connection] that still has 250 ** outstanding [prepared statements] or [BLOB handles], then it returns 251 ** SQLITE_BUSY. 252 ** 253 ** ^If [sqlite3_close()] is invoked while a transaction is open, 254 ** the transaction is automatically rolled back. 255 ** 256 ** The C parameter to [sqlite3_close(C)] must be either a NULL 257 ** pointer or an [sqlite3] object pointer obtained 258 ** from [sqlite3_open()], [sqlite3_open16()], or 259 ** [sqlite3_open_v2()], and not previously closed. 260 ** ^Calling sqlite3_close() with a NULL pointer argument is a 261 ** harmless no-op. 262 */ 263 SQLITE_API int sqlite3_close(sqlite3 *); 264 265 /* 266 ** The type for a callback function. 267 ** This is legacy and deprecated. It is included for historical 268 ** compatibility and is not documented. 269 */ 270 typedef int (*sqlite3_callback)(void*,int,char**, char**); 271 272 /* 273 ** CAPI3REF: One-Step Query Execution Interface 274 ** 275 ** The sqlite3_exec() interface is a convenience wrapper around 276 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 277 ** that allows an application to run multiple statements of SQL 278 ** without having to use a lot of C code. 279 ** 280 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 281 ** semicolon-separate SQL statements passed into its 2nd argument, 282 ** in the context of the [database connection] passed in as its 1st 283 ** argument. ^If the callback function of the 3rd argument to 284 ** sqlite3_exec() is not NULL, then it is invoked for each result row 285 ** coming out of the evaluated SQL statements. ^The 4th argument to 286 ** to sqlite3_exec() is relayed through to the 1st argument of each 287 ** callback invocation. ^If the callback pointer to sqlite3_exec() 288 ** is NULL, then no callback is ever invoked and result rows are 289 ** ignored. 290 ** 291 ** ^If an error occurs while evaluating the SQL statements passed into 292 ** sqlite3_exec(), then execution of the current statement stops and 293 ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 294 ** is not NULL then any error message is written into memory obtained 295 ** from [sqlite3_malloc()] and passed back through the 5th parameter. 296 ** To avoid memory leaks, the application should invoke [sqlite3_free()] 297 ** on error message strings returned through the 5th parameter of 298 ** of sqlite3_exec() after the error message string is no longer needed. 299 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 300 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 301 ** NULL before returning. 302 ** 303 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 304 ** routine returns SQLITE_ABORT without invoking the callback again and 305 ** without running any subsequent SQL statements. 306 ** 307 ** ^The 2nd argument to the sqlite3_exec() callback function is the 308 ** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 309 ** callback is an array of pointers to strings obtained as if from 310 ** [sqlite3_column_text()], one for each column. ^If an element of a 311 ** result row is NULL then the corresponding string pointer for the 312 ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 313 ** sqlite3_exec() callback is an array of pointers to strings where each 314 ** entry represents the name of corresponding result column as obtained 315 ** from [sqlite3_column_name()]. 316 ** 317 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 318 ** to an empty string, or a pointer that contains only whitespace and/or 319 ** SQL comments, then no SQL statements are evaluated and the database 320 ** is not changed. 321 ** 322 ** Restrictions: 323 ** 324 ** <ul> 325 ** <li> The application must insure that the 1st parameter to sqlite3_exec() 326 ** is a valid and open [database connection]. 327 ** <li> The application must not close [database connection] specified by 328 ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 329 ** <li> The application must not modify the SQL statement text passed into 330 ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 331 ** </ul> 332 */ 333 SQLITE_API int sqlite3_exec( 334 sqlite3*, /* An open database */ 335 const char *sql, /* SQL to be evaluated */ 336 int (*callback)(void*,int,char**,char**), /* Callback function */ 337 void *, /* 1st argument to callback */ 338 char **errmsg /* Error msg written here */ 339 ); 340 341 /* 342 ** CAPI3REF: Result Codes 343 ** KEYWORDS: SQLITE_OK {error code} {error codes} 344 ** KEYWORDS: {result code} {result codes} 345 ** 346 ** Many SQLite functions return an integer result code from the set shown 347 ** here in order to indicates success or failure. 348 ** 349 ** New error codes may be added in future versions of SQLite. 350 ** 351 ** See also: [SQLITE_IOERR_READ | extended result codes] 352 */ 353 #define SQLITE_OK 0 /* Successful result */ 354 /* beginning-of-error-codes */ 355 #define SQLITE_ERROR 1 /* SQL error or missing database */ 356 #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 357 #define SQLITE_PERM 3 /* Access permission denied */ 358 #define SQLITE_ABORT 4 /* Callback routine requested an abort */ 359 #define SQLITE_BUSY 5 /* The database file is locked */ 360 #define SQLITE_LOCKED 6 /* A table in the database is locked */ 361 #define SQLITE_NOMEM 7 /* A malloc() failed */ 362 #define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 363 #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 364 #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 365 #define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 366 #define SQLITE_NOTFOUND 12 /* NOT USED. Table or record not found */ 367 #define SQLITE_FULL 13 /* Insertion failed because database is full */ 368 #define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 369 #define SQLITE_PROTOCOL 15 /* NOT USED. Database lock protocol error */ 370 #define SQLITE_EMPTY 16 /* Database is empty */ 371 #define SQLITE_SCHEMA 17 /* The database schema changed */ 372 #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 373 #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 374 #define SQLITE_MISMATCH 20 /* Data type mismatch */ 375 #define SQLITE_MISUSE 21 /* Library used incorrectly */ 376 #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 377 #define SQLITE_AUTH 23 /* Authorization denied */ 378 #define SQLITE_FORMAT 24 /* Auxiliary database format error */ 379 #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 380 #define SQLITE_NOTADB 26 /* File opened that is not a database file */ 381 #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 382 #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 383 /* end-of-error-codes */ 384 385 /* 386 ** CAPI3REF: Extended Result Codes 387 ** KEYWORDS: {extended error code} {extended error codes} 388 ** KEYWORDS: {extended result code} {extended result codes} 389 ** 390 ** In its default configuration, SQLite API routines return one of 26 integer 391 ** [SQLITE_OK | result codes]. However, experience has shown that many of 392 ** these result codes are too coarse-grained. They do not provide as 393 ** much information about problems as programmers might like. In an effort to 394 ** address this, newer versions of SQLite (version 3.3.8 and later) include 395 ** support for additional result codes that provide more detailed information 396 ** about errors. The extended result codes are enabled or disabled 397 ** on a per database connection basis using the 398 ** [sqlite3_extended_result_codes()] API. 399 ** 400 ** Some of the available extended result codes are listed here. 401 ** One may expect the number of extended result codes will be expand 402 ** over time. Software that uses extended result codes should expect 403 ** to see new result codes in future releases of SQLite. 404 ** 405 ** The SQLITE_OK result code will never be extended. It will always 406 ** be exactly zero. 407 */ 408 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 409 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 410 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 411 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 412 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 413 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 414 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 415 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 416 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 417 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 418 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 419 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 420 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 421 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 422 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 423 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 424 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 425 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8) ) 426 427 /* 428 ** CAPI3REF: Flags For File Open Operations 429 ** 430 ** These bit values are intended for use in the 431 ** 3rd parameter to the [sqlite3_open_v2()] interface and 432 ** in the 4th parameter to the xOpen method of the 433 ** [sqlite3_vfs] object. 434 */ 435 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 436 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 437 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 438 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 439 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 440 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 441 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 442 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 443 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 444 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 445 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 446 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 447 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 448 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 449 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 450 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 451 452 /* 453 ** CAPI3REF: Device Characteristics 454 ** 455 ** The xDeviceCapabilities method of the [sqlite3_io_methods] 456 ** object returns an integer which is a vector of the these 457 ** bit values expressing I/O characteristics of the mass storage 458 ** device that holds the file that the [sqlite3_io_methods] 459 ** refers to. 460 ** 461 ** The SQLITE_IOCAP_ATOMIC property means that all writes of 462 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 463 ** mean that writes of blocks that are nnn bytes in size and 464 ** are aligned to an address which is an integer multiple of 465 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 466 ** that when data is appended to a file, the data is appended 467 ** first then the size of the file is extended, never the other 468 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 469 ** information is written to disk in the same order as calls 470 ** to xWrite(). 471 */ 472 #define SQLITE_IOCAP_ATOMIC 0x00000001 473 #define SQLITE_IOCAP_ATOMIC512 0x00000002 474 #define SQLITE_IOCAP_ATOMIC1K 0x00000004 475 #define SQLITE_IOCAP_ATOMIC2K 0x00000008 476 #define SQLITE_IOCAP_ATOMIC4K 0x00000010 477 #define SQLITE_IOCAP_ATOMIC8K 0x00000020 478 #define SQLITE_IOCAP_ATOMIC16K 0x00000040 479 #define SQLITE_IOCAP_ATOMIC32K 0x00000080 480 #define SQLITE_IOCAP_ATOMIC64K 0x00000100 481 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200 482 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400 483 484 /* 485 ** CAPI3REF: File Locking Levels 486 ** 487 ** SQLite uses one of these integer values as the second 488 ** argument to calls it makes to the xLock() and xUnlock() methods 489 ** of an [sqlite3_io_methods] object. 490 */ 491 #define SQLITE_LOCK_NONE 0 492 #define SQLITE_LOCK_SHARED 1 493 #define SQLITE_LOCK_RESERVED 2 494 #define SQLITE_LOCK_PENDING 3 495 #define SQLITE_LOCK_EXCLUSIVE 4 496 497 /* 498 ** CAPI3REF: Synchronization Type Flags 499 ** 500 ** When SQLite invokes the xSync() method of an 501 ** [sqlite3_io_methods] object it uses a combination of 502 ** these integer values as the second argument. 503 ** 504 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 505 ** sync operation only needs to flush data to mass storage. Inode 506 ** information need not be flushed. If the lower four bits of the flag 507 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 508 ** If the lower four bits equal SQLITE_SYNC_FULL, that means 509 ** to use Mac OS X style fullsync instead of fsync(). 510 */ 511 #define SQLITE_SYNC_NORMAL 0x00002 512 #define SQLITE_SYNC_FULL 0x00003 513 #define SQLITE_SYNC_DATAONLY 0x00010 514 515 /* 516 ** CAPI3REF: OS Interface Open File Handle 517 ** 518 ** An [sqlite3_file] object represents an open file in the 519 ** [sqlite3_vfs | OS interface layer]. Individual OS interface 520 ** implementations will 521 ** want to subclass this object by appending additional fields 522 ** for their own use. The pMethods entry is a pointer to an 523 ** [sqlite3_io_methods] object that defines methods for performing 524 ** I/O operations on the open file. 525 */ 526 typedef struct sqlite3_file sqlite3_file; 527 struct sqlite3_file { 528 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 529 }; 530 531 /* 532 ** CAPI3REF: OS Interface File Virtual Methods Object 533 ** 534 ** Every file opened by the [sqlite3_vfs] xOpen method populates an 535 ** [sqlite3_file] object (or, more commonly, a subclass of the 536 ** [sqlite3_file] object) with a pointer to an instance of this object. 537 ** This object defines the methods used to perform various operations 538 ** against the open file represented by the [sqlite3_file] object. 539 ** 540 ** If the xOpen method sets the sqlite3_file.pMethods element 541 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 542 ** may be invoked even if the xOpen reported that it failed. The 543 ** only way to prevent a call to xClose following a failed xOpen 544 ** is for the xOpen to set the sqlite3_file.pMethods element to NULL. 545 ** 546 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 547 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 548 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 549 ** flag may be ORed in to indicate that only the data of the file 550 ** and not its inode needs to be synced. 551 ** 552 ** The integer values to xLock() and xUnlock() are one of 553 ** <ul> 554 ** <li> [SQLITE_LOCK_NONE], 555 ** <li> [SQLITE_LOCK_SHARED], 556 ** <li> [SQLITE_LOCK_RESERVED], 557 ** <li> [SQLITE_LOCK_PENDING], or 558 ** <li> [SQLITE_LOCK_EXCLUSIVE]. 559 ** </ul> 560 ** xLock() increases the lock. xUnlock() decreases the lock. 561 ** The xCheckReservedLock() method checks whether any database connection, 562 ** either in this process or in some other process, is holding a RESERVED, 563 ** PENDING, or EXCLUSIVE lock on the file. It returns true 564 ** if such a lock exists and false otherwise. 565 ** 566 ** The xFileControl() method is a generic interface that allows custom 567 ** VFS implementations to directly control an open file using the 568 ** [sqlite3_file_control()] interface. The second "op" argument is an 569 ** integer opcode. The third argument is a generic pointer intended to 570 ** point to a structure that may contain arguments or space in which to 571 ** write return values. Potential uses for xFileControl() might be 572 ** functions to enable blocking locks with timeouts, to change the 573 ** locking strategy (for example to use dot-file locks), to inquire 574 ** about the status of a lock, or to break stale locks. The SQLite 575 ** core reserves all opcodes less than 100 for its own use. 576 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 577 ** Applications that define a custom xFileControl method should use opcodes 578 ** greater than 100 to avoid conflicts. 579 ** 580 ** The xSectorSize() method returns the sector size of the 581 ** device that underlies the file. The sector size is the 582 ** minimum write that can be performed without disturbing 583 ** other bytes in the file. The xDeviceCharacteristics() 584 ** method returns a bit vector describing behaviors of the 585 ** underlying device: 586 ** 587 ** <ul> 588 ** <li> [SQLITE_IOCAP_ATOMIC] 589 ** <li> [SQLITE_IOCAP_ATOMIC512] 590 ** <li> [SQLITE_IOCAP_ATOMIC1K] 591 ** <li> [SQLITE_IOCAP_ATOMIC2K] 592 ** <li> [SQLITE_IOCAP_ATOMIC4K] 593 ** <li> [SQLITE_IOCAP_ATOMIC8K] 594 ** <li> [SQLITE_IOCAP_ATOMIC16K] 595 ** <li> [SQLITE_IOCAP_ATOMIC32K] 596 ** <li> [SQLITE_IOCAP_ATOMIC64K] 597 ** <li> [SQLITE_IOCAP_SAFE_APPEND] 598 ** <li> [SQLITE_IOCAP_SEQUENTIAL] 599 ** </ul> 600 ** 601 ** The SQLITE_IOCAP_ATOMIC property means that all writes of 602 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 603 ** mean that writes of blocks that are nnn bytes in size and 604 ** are aligned to an address which is an integer multiple of 605 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 606 ** that when data is appended to a file, the data is appended 607 ** first then the size of the file is extended, never the other 608 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 609 ** information is written to disk in the same order as calls 610 ** to xWrite(). 611 ** 612 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 613 ** in the unread portions of the buffer with zeros. A VFS that 614 ** fails to zero-fill short reads might seem to work. However, 615 ** failure to zero-fill short reads will eventually lead to 616 ** database corruption. 617 */ 618 typedef struct sqlite3_io_methods sqlite3_io_methods; 619 struct sqlite3_io_methods { 620 int iVersion; 621 int (*xClose)(sqlite3_file*); 622 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 623 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 624 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 625 int (*xSync)(sqlite3_file*, int flags); 626 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 627 int (*xLock)(sqlite3_file*, int); 628 int (*xUnlock)(sqlite3_file*, int); 629 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 630 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 631 int (*xSectorSize)(sqlite3_file*); 632 int (*xDeviceCharacteristics)(sqlite3_file*); 633 /* Additional methods may be added in future releases */ 634 }; 635 636 /* 637 ** CAPI3REF: Standard File Control Opcodes 638 ** 639 ** These integer constants are opcodes for the xFileControl method 640 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 641 ** interface. 642 ** 643 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 644 ** opcode causes the xFileControl method to write the current state of 645 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 646 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 647 ** into an integer that the pArg argument points to. This capability 648 ** is used during testing and only needs to be supported when SQLITE_TEST 649 ** is defined. 650 */ 651 #define SQLITE_FCNTL_LOCKSTATE 1 652 #define SQLITE_GET_LOCKPROXYFILE 2 653 #define SQLITE_SET_LOCKPROXYFILE 3 654 #define SQLITE_LAST_ERRNO 4 655 656 /* 657 ** CAPI3REF: Mutex Handle 658 ** 659 ** The mutex module within SQLite defines [sqlite3_mutex] to be an 660 ** abstract type for a mutex object. The SQLite core never looks 661 ** at the internal representation of an [sqlite3_mutex]. It only 662 ** deals with pointers to the [sqlite3_mutex] object. 663 ** 664 ** Mutexes are created using [sqlite3_mutex_alloc()]. 665 */ 666 typedef struct sqlite3_mutex sqlite3_mutex; 667 668 /* 669 ** CAPI3REF: OS Interface Object 670 ** 671 ** An instance of the sqlite3_vfs object defines the interface between 672 ** the SQLite core and the underlying operating system. The "vfs" 673 ** in the name of the object stands for "virtual file system". 674 ** 675 ** The value of the iVersion field is initially 1 but may be larger in 676 ** future versions of SQLite. Additional fields may be appended to this 677 ** object when the iVersion value is increased. Note that the structure 678 ** of the sqlite3_vfs object changes in the transaction between 679 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 680 ** modified. 681 ** 682 ** The szOsFile field is the size of the subclassed [sqlite3_file] 683 ** structure used by this VFS. mxPathname is the maximum length of 684 ** a pathname in this VFS. 685 ** 686 ** Registered sqlite3_vfs objects are kept on a linked list formed by 687 ** the pNext pointer. The [sqlite3_vfs_register()] 688 ** and [sqlite3_vfs_unregister()] interfaces manage this list 689 ** in a thread-safe way. The [sqlite3_vfs_find()] interface 690 ** searches the list. Neither the application code nor the VFS 691 ** implementation should use the pNext pointer. 692 ** 693 ** The pNext field is the only field in the sqlite3_vfs 694 ** structure that SQLite will ever modify. SQLite will only access 695 ** or modify this field while holding a particular static mutex. 696 ** The application should never modify anything within the sqlite3_vfs 697 ** object once the object has been registered. 698 ** 699 ** The zName field holds the name of the VFS module. The name must 700 ** be unique across all VFS modules. 701 ** 702 ** SQLite will guarantee that the zFilename parameter to xOpen 703 ** is either a NULL pointer or string obtained 704 ** from xFullPathname(). SQLite further guarantees that 705 ** the string will be valid and unchanged until xClose() is 706 ** called. Because of the previous sentence, 707 ** the [sqlite3_file] can safely store a pointer to the 708 ** filename if it needs to remember the filename for some reason. 709 ** If the zFilename parameter is xOpen is a NULL pointer then xOpen 710 ** must invent its own temporary name for the file. Whenever the 711 ** xFilename parameter is NULL it will also be the case that the 712 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 713 ** 714 ** The flags argument to xOpen() includes all bits set in 715 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 716 ** or [sqlite3_open16()] is used, then flags includes at least 717 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 718 ** If xOpen() opens a file read-only then it sets *pOutFlags to 719 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 720 ** 721 ** SQLite will also add one of the following flags to the xOpen() 722 ** call, depending on the object being opened: 723 ** 724 ** <ul> 725 ** <li> [SQLITE_OPEN_MAIN_DB] 726 ** <li> [SQLITE_OPEN_MAIN_JOURNAL] 727 ** <li> [SQLITE_OPEN_TEMP_DB] 728 ** <li> [SQLITE_OPEN_TEMP_JOURNAL] 729 ** <li> [SQLITE_OPEN_TRANSIENT_DB] 730 ** <li> [SQLITE_OPEN_SUBJOURNAL] 731 ** <li> [SQLITE_OPEN_MASTER_JOURNAL] 732 ** </ul> 733 ** 734 ** The file I/O implementation can use the object type flags to 735 ** change the way it deals with files. For example, an application 736 ** that does not care about crash recovery or rollback might make 737 ** the open of a journal file a no-op. Writes to this journal would 738 ** also be no-ops, and any attempt to read the journal would return 739 ** SQLITE_IOERR. Or the implementation might recognize that a database 740 ** file will be doing page-aligned sector reads and writes in a random 741 ** order and set up its I/O subsystem accordingly. 742 ** 743 ** SQLite might also add one of the following flags to the xOpen method: 744 ** 745 ** <ul> 746 ** <li> [SQLITE_OPEN_DELETEONCLOSE] 747 ** <li> [SQLITE_OPEN_EXCLUSIVE] 748 ** </ul> 749 ** 750 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 751 ** deleted when it is closed. The [SQLITE_OPEN_DELETEONCLOSE] 752 ** will be set for TEMP databases, journals and for subjournals. 753 ** 754 ** The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 755 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly 756 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 757 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 758 ** SQLITE_OPEN_CREATE, is used to indicate that file should always 759 ** be created, and that it is an error if it already exists. 760 ** It is <i>not</i> used to indicate the file should be opened 761 ** for exclusive access. 762 ** 763 ** At least szOsFile bytes of memory are allocated by SQLite 764 ** to hold the [sqlite3_file] structure passed as the third 765 ** argument to xOpen. The xOpen method does not have to 766 ** allocate the structure; it should just fill it in. Note that 767 ** the xOpen method must set the sqlite3_file.pMethods to either 768 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 769 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 770 ** element will be valid after xOpen returns regardless of the success 771 ** or failure of the xOpen call. 772 ** 773 ** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 774 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 775 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 776 ** to test whether a file is at least readable. The file can be a 777 ** directory. 778 ** 779 ** SQLite will always allocate at least mxPathname+1 bytes for the 780 ** output buffer xFullPathname. The exact size of the output buffer 781 ** is also passed as a parameter to both methods. If the output buffer 782 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 783 ** handled as a fatal error by SQLite, vfs implementations should endeavor 784 ** to prevent this by setting mxPathname to a sufficiently large value. 785 ** 786 ** The xRandomness(), xSleep(), and xCurrentTime() interfaces 787 ** are not strictly a part of the filesystem, but they are 788 ** included in the VFS structure for completeness. 789 ** The xRandomness() function attempts to return nBytes bytes 790 ** of good-quality randomness into zOut. The return value is 791 ** the actual number of bytes of randomness obtained. 792 ** The xSleep() method causes the calling thread to sleep for at 793 ** least the number of microseconds given. The xCurrentTime() 794 ** method returns a Julian Day Number for the current date and time. 795 ** 796 */ 797 typedef struct sqlite3_vfs sqlite3_vfs; 798 struct sqlite3_vfs { 799 int iVersion; /* Structure version number */ 800 int szOsFile; /* Size of subclassed sqlite3_file */ 801 int mxPathname; /* Maximum file pathname length */ 802 sqlite3_vfs *pNext; /* Next registered VFS */ 803 const char *zName; /* Name of this virtual file system */ 804 void *pAppData; /* Pointer to application-specific data */ 805 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 806 int flags, int *pOutFlags); 807 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 808 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 809 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 810 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 811 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 812 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 813 void (*xDlClose)(sqlite3_vfs*, void*); 814 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 815 int (*xSleep)(sqlite3_vfs*, int microseconds); 816 int (*xCurrentTime)(sqlite3_vfs*, double*); 817 int (*xGetLastError)(sqlite3_vfs*, int, char *); 818 /* New fields may be appended in figure versions. The iVersion 819 ** value will increment whenever this happens. */ 820 }; 821 822 /* 823 ** CAPI3REF: Flags for the xAccess VFS method 824 ** 825 ** These integer constants can be used as the third parameter to 826 ** the xAccess method of an [sqlite3_vfs] object. They determine 827 ** what kind of permissions the xAccess method is looking for. 828 ** With SQLITE_ACCESS_EXISTS, the xAccess method 829 ** simply checks whether the file exists. 830 ** With SQLITE_ACCESS_READWRITE, the xAccess method 831 ** checks whether the file is both readable and writable. 832 ** With SQLITE_ACCESS_READ, the xAccess method 833 ** checks whether the file is readable. 834 */ 835 #define SQLITE_ACCESS_EXISTS 0 836 #define SQLITE_ACCESS_READWRITE 1 837 #define SQLITE_ACCESS_READ 2 838 839 /* 840 ** CAPI3REF: Initialize The SQLite Library 841 ** 842 ** ^The sqlite3_initialize() routine initializes the 843 ** SQLite library. ^The sqlite3_shutdown() routine 844 ** deallocates any resources that were allocated by sqlite3_initialize(). 845 ** These routines are designed to aid in process initialization and 846 ** shutdown on embedded systems. Workstation applications using 847 ** SQLite normally do not need to invoke either of these routines. 848 ** 849 ** A call to sqlite3_initialize() is an "effective" call if it is 850 ** the first time sqlite3_initialize() is invoked during the lifetime of 851 ** the process, or if it is the first time sqlite3_initialize() is invoked 852 ** following a call to sqlite3_shutdown(). ^(Only an effective call 853 ** of sqlite3_initialize() does any initialization. All other calls 854 ** are harmless no-ops.)^ 855 ** 856 ** A call to sqlite3_shutdown() is an "effective" call if it is the first 857 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 858 ** an effective call to sqlite3_shutdown() does any deinitialization. 859 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 860 ** 861 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 862 ** is not. The sqlite3_shutdown() interface must only be called from a 863 ** single thread. All open [database connections] must be closed and all 864 ** other SQLite resources must be deallocated prior to invoking 865 ** sqlite3_shutdown(). 866 ** 867 ** Among other things, ^sqlite3_initialize() will invoke 868 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 869 ** will invoke sqlite3_os_end(). 870 ** 871 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 872 ** ^If for some reason, sqlite3_initialize() is unable to initialize 873 ** the library (perhaps it is unable to allocate a needed resource such 874 ** as a mutex) it returns an [error code] other than [SQLITE_OK]. 875 ** 876 ** ^The sqlite3_initialize() routine is called internally by many other 877 ** SQLite interfaces so that an application usually does not need to 878 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 879 ** calls sqlite3_initialize() so the SQLite library will be automatically 880 ** initialized when [sqlite3_open()] is called if it has not be initialized 881 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 882 ** compile-time option, then the automatic calls to sqlite3_initialize() 883 ** are omitted and the application must call sqlite3_initialize() directly 884 ** prior to using any other SQLite interface. For maximum portability, 885 ** it is recommended that applications always invoke sqlite3_initialize() 886 ** directly prior to using any other SQLite interface. Future releases 887 ** of SQLite may require this. In other words, the behavior exhibited 888 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 889 ** default behavior in some future release of SQLite. 890 ** 891 ** The sqlite3_os_init() routine does operating-system specific 892 ** initialization of the SQLite library. The sqlite3_os_end() 893 ** routine undoes the effect of sqlite3_os_init(). Typical tasks 894 ** performed by these routines include allocation or deallocation 895 ** of static resources, initialization of global variables, 896 ** setting up a default [sqlite3_vfs] module, or setting up 897 ** a default configuration using [sqlite3_config()]. 898 ** 899 ** The application should never invoke either sqlite3_os_init() 900 ** or sqlite3_os_end() directly. The application should only invoke 901 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 902 ** interface is called automatically by sqlite3_initialize() and 903 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 904 ** implementations for sqlite3_os_init() and sqlite3_os_end() 905 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 906 ** When [custom builds | built for other platforms] 907 ** (using the [SQLITE_OS_OTHER=1] compile-time 908 ** option) the application must supply a suitable implementation for 909 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 910 ** implementation of sqlite3_os_init() or sqlite3_os_end() 911 ** must return [SQLITE_OK] on success and some other [error code] upon 912 ** failure. 913 */ 914 SQLITE_API int sqlite3_initialize(void); 915 SQLITE_API int sqlite3_shutdown(void); 916 SQLITE_API int sqlite3_os_init(void); 917 SQLITE_API int sqlite3_os_end(void); 918 919 /* 920 ** CAPI3REF: Configuring The SQLite Library 921 ** 922 ** The sqlite3_config() interface is used to make global configuration 923 ** changes to SQLite in order to tune SQLite to the specific needs of 924 ** the application. The default configuration is recommended for most 925 ** applications and so this routine is usually not necessary. It is 926 ** provided to support rare applications with unusual needs. 927 ** 928 ** The sqlite3_config() interface is not threadsafe. The application 929 ** must insure that no other SQLite interfaces are invoked by other 930 ** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 931 ** may only be invoked prior to library initialization using 932 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 933 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 934 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 935 ** Note, however, that ^sqlite3_config() can be called as part of the 936 ** implementation of an application-defined [sqlite3_os_init()]. 937 ** 938 ** The first argument to sqlite3_config() is an integer 939 ** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines 940 ** what property of SQLite is to be configured. Subsequent arguments 941 ** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option] 942 ** in the first argument. 943 ** 944 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 945 ** ^If the option is unknown or SQLite is unable to set the option 946 ** then this routine returns a non-zero [error code]. 947 */ 948 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_config(int, ...); 949 950 /* 951 ** CAPI3REF: Configure database connections 952 ** EXPERIMENTAL 953 ** 954 ** The sqlite3_db_config() interface is used to make configuration 955 ** changes to a [database connection]. The interface is similar to 956 ** [sqlite3_config()] except that the changes apply to a single 957 ** [database connection] (specified in the first argument). The 958 ** sqlite3_db_config() interface should only be used immediately after 959 ** the database connection is created using [sqlite3_open()], 960 ** [sqlite3_open16()], or [sqlite3_open_v2()]. 961 ** 962 ** The second argument to sqlite3_db_config(D,V,...) is the 963 ** configuration verb - an integer code that indicates what 964 ** aspect of the [database connection] is being configured. 965 ** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE]. 966 ** New verbs are likely to be added in future releases of SQLite. 967 ** Additional arguments depend on the verb. 968 ** 969 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 970 ** the call is considered successful. 971 */ 972 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...); 973 974 /* 975 ** CAPI3REF: Memory Allocation Routines 976 ** EXPERIMENTAL 977 ** 978 ** An instance of this object defines the interface between SQLite 979 ** and low-level memory allocation routines. 980 ** 981 ** This object is used in only one place in the SQLite interface. 982 ** A pointer to an instance of this object is the argument to 983 ** [sqlite3_config()] when the configuration option is 984 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 985 ** By creating an instance of this object 986 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 987 ** during configuration, an application can specify an alternative 988 ** memory allocation subsystem for SQLite to use for all of its 989 ** dynamic memory needs. 990 ** 991 ** Note that SQLite comes with several [built-in memory allocators] 992 ** that are perfectly adequate for the overwhelming majority of applications 993 ** and that this object is only useful to a tiny minority of applications 994 ** with specialized memory allocation requirements. This object is 995 ** also used during testing of SQLite in order to specify an alternative 996 ** memory allocator that simulates memory out-of-memory conditions in 997 ** order to verify that SQLite recovers gracefully from such 998 ** conditions. 999 ** 1000 ** The xMalloc and xFree methods must work like the 1001 ** malloc() and free() functions from the standard C library. 1002 ** The xRealloc method must work like realloc() from the standard C library 1003 ** with the exception that if the second argument to xRealloc is zero, 1004 ** xRealloc must be a no-op - it must not perform any allocation or 1005 ** deallocation. ^SQLite guarantees that the second argument to 1006 ** xRealloc is always a value returned by a prior call to xRoundup. 1007 ** And so in cases where xRoundup always returns a positive number, 1008 ** xRealloc can perform exactly as the standard library realloc() and 1009 ** still be in compliance with this specification. 1010 ** 1011 ** xSize should return the allocated size of a memory allocation 1012 ** previously obtained from xMalloc or xRealloc. The allocated size 1013 ** is always at least as big as the requested size but may be larger. 1014 ** 1015 ** The xRoundup method returns what would be the allocated size of 1016 ** a memory allocation given a particular requested size. Most memory 1017 ** allocators round up memory allocations at least to the next multiple 1018 ** of 8. Some allocators round up to a larger multiple or to a power of 2. 1019 ** Every memory allocation request coming in through [sqlite3_malloc()] 1020 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1021 ** that causes the corresponding memory allocation to fail. 1022 ** 1023 ** The xInit method initializes the memory allocator. (For example, 1024 ** it might allocate any require mutexes or initialize internal data 1025 ** structures. The xShutdown method is invoked (indirectly) by 1026 ** [sqlite3_shutdown()] and should deallocate any resources acquired 1027 ** by xInit. The pAppData pointer is used as the only parameter to 1028 ** xInit and xShutdown. 1029 ** 1030 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1031 ** the xInit method, so the xInit method need not be threadsafe. The 1032 ** xShutdown method is only called from [sqlite3_shutdown()] so it does 1033 ** not need to be threadsafe either. For all other methods, SQLite 1034 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1035 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1036 ** it is by default) and so the methods are automatically serialized. 1037 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1038 ** methods must be threadsafe or else make their own arrangements for 1039 ** serialization. 1040 ** 1041 ** SQLite will never invoke xInit() more than once without an intervening 1042 ** call to xShutdown(). 1043 */ 1044 typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1045 struct sqlite3_mem_methods { 1046 void *(*xMalloc)(int); /* Memory allocation function */ 1047 void (*xFree)(void*); /* Free a prior allocation */ 1048 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1049 int (*xSize)(void*); /* Return the size of an allocation */ 1050 int (*xRoundup)(int); /* Round up request size to allocation size */ 1051 int (*xInit)(void*); /* Initialize the memory allocator */ 1052 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1053 void *pAppData; /* Argument to xInit() and xShutdown() */ 1054 }; 1055 1056 /* 1057 ** CAPI3REF: Configuration Options 1058 ** EXPERIMENTAL 1059 ** 1060 ** These constants are the available integer configuration options that 1061 ** can be passed as the first argument to the [sqlite3_config()] interface. 1062 ** 1063 ** New configuration options may be added in future releases of SQLite. 1064 ** Existing configuration options might be discontinued. Applications 1065 ** should check the return code from [sqlite3_config()] to make sure that 1066 ** the call worked. The [sqlite3_config()] interface will return a 1067 ** non-zero [error code] if a discontinued or unsupported configuration option 1068 ** is invoked. 1069 ** 1070 ** <dl> 1071 ** <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1072 ** <dd>There are no arguments to this option. ^This option sets the 1073 ** [threading mode] to Single-thread. In other words, it disables 1074 ** all mutexing and puts SQLite into a mode where it can only be used 1075 ** by a single thread. ^If SQLite is compiled with 1076 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1077 ** it is not possible to change the [threading mode] from its default 1078 ** value of Single-thread and so [sqlite3_config()] will return 1079 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1080 ** configuration option.</dd> 1081 ** 1082 ** <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1083 ** <dd>There are no arguments to this option. ^This option sets the 1084 ** [threading mode] to Multi-thread. In other words, it disables 1085 ** mutexing on [database connection] and [prepared statement] objects. 1086 ** The application is responsible for serializing access to 1087 ** [database connections] and [prepared statements]. But other mutexes 1088 ** are enabled so that SQLite will be safe to use in a multi-threaded 1089 ** environment as long as no two threads attempt to use the same 1090 ** [database connection] at the same time. ^If SQLite is compiled with 1091 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1092 ** it is not possible to set the Multi-thread [threading mode] and 1093 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1094 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1095 ** 1096 ** <dt>SQLITE_CONFIG_SERIALIZED</dt> 1097 ** <dd>There are no arguments to this option. ^This option sets the 1098 ** [threading mode] to Serialized. In other words, this option enables 1099 ** all mutexes including the recursive 1100 ** mutexes on [database connection] and [prepared statement] objects. 1101 ** In this mode (which is the default when SQLite is compiled with 1102 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1103 ** to [database connections] and [prepared statements] so that the 1104 ** application is free to use the same [database connection] or the 1105 ** same [prepared statement] in different threads at the same time. 1106 ** ^If SQLite is compiled with 1107 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1108 ** it is not possible to set the Serialized [threading mode] and 1109 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1110 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1111 ** 1112 ** <dt>SQLITE_CONFIG_MALLOC</dt> 1113 ** <dd> ^(This option takes a single argument which is a pointer to an 1114 ** instance of the [sqlite3_mem_methods] structure. The argument specifies 1115 ** alternative low-level memory allocation routines to be used in place of 1116 ** the memory allocation routines built into SQLite.)^ ^SQLite makes 1117 ** its own private copy of the content of the [sqlite3_mem_methods] structure 1118 ** before the [sqlite3_config()] call returns.</dd> 1119 ** 1120 ** <dt>SQLITE_CONFIG_GETMALLOC</dt> 1121 ** <dd> ^(This option takes a single argument which is a pointer to an 1122 ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1123 ** structure is filled with the currently defined memory allocation routines.)^ 1124 ** This option can be used to overload the default memory allocation 1125 ** routines with a wrapper that simulations memory allocation failure or 1126 ** tracks memory usage, for example. </dd> 1127 ** 1128 ** <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1129 ** <dd> ^This option takes single argument of type int, interpreted as a 1130 ** boolean, which enables or disables the collection of memory allocation 1131 ** statistics. ^(When memory allocation statistics are disabled, the 1132 ** following SQLite interfaces become non-operational: 1133 ** <ul> 1134 ** <li> [sqlite3_memory_used()] 1135 ** <li> [sqlite3_memory_highwater()] 1136 ** <li> [sqlite3_soft_heap_limit()] 1137 ** <li> [sqlite3_status()] 1138 ** </ul>)^ 1139 ** ^Memory allocation statistics are enabled by default unless SQLite is 1140 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1141 ** allocation statistics are disabled by default. 1142 ** </dd> 1143 ** 1144 ** <dt>SQLITE_CONFIG_SCRATCH</dt> 1145 ** <dd> ^This option specifies a static memory buffer that SQLite can use for 1146 ** scratch memory. There are three arguments: A pointer an 8-byte 1147 ** aligned memory buffer from which the scrach allocations will be 1148 ** drawn, the size of each scratch allocation (sz), 1149 ** and the maximum number of scratch allocations (N). The sz 1150 ** argument must be a multiple of 16. The sz parameter should be a few bytes 1151 ** larger than the actual scratch space required due to internal overhead. 1152 ** The first argument must be a pointer to an 8-byte aligned buffer 1153 ** of at least sz*N bytes of memory. 1154 ** ^SQLite will use no more than one scratch buffer per thread. So 1155 ** N should be set to the expected maximum number of threads. ^SQLite will 1156 ** never require a scratch buffer that is more than 6 times the database 1157 ** page size. ^If SQLite needs needs additional scratch memory beyond 1158 ** what is provided by this configuration option, then 1159 ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1160 ** 1161 ** <dt>SQLITE_CONFIG_PAGECACHE</dt> 1162 ** <dd> ^This option specifies a static memory buffer that SQLite can use for 1163 ** the database page cache with the default page cache implemenation. 1164 ** This configuration should not be used if an application-define page 1165 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option. 1166 ** There are three arguments to this option: A pointer to 8-byte aligned 1167 ** memory, the size of each page buffer (sz), and the number of pages (N). 1168 ** The sz argument should be the size of the largest database page 1169 ** (a power of two between 512 and 32768) plus a little extra for each 1170 ** page header. ^The page header size is 20 to 40 bytes depending on 1171 ** the host architecture. ^It is harmless, apart from the wasted memory, 1172 ** to make sz a little too large. The first 1173 ** argument should point to an allocation of at least sz*N bytes of memory. 1174 ** ^SQLite will use the memory provided by the first argument to satisfy its 1175 ** memory needs for the first N pages that it adds to cache. ^If additional 1176 ** page cache memory is needed beyond what is provided by this option, then 1177 ** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1178 ** ^The implementation might use one or more of the N buffers to hold 1179 ** memory accounting information. The pointer in the first argument must 1180 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1181 ** will be undefined.</dd> 1182 ** 1183 ** <dt>SQLITE_CONFIG_HEAP</dt> 1184 ** <dd> ^This option specifies a static memory buffer that SQLite will use 1185 ** for all of its dynamic memory allocation needs beyond those provided 1186 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1187 ** There are three arguments: An 8-byte aligned pointer to the memory, 1188 ** the number of bytes in the memory buffer, and the minimum allocation size. 1189 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1190 ** to using its default memory allocator (the system malloc() implementation), 1191 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1192 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1193 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1194 ** allocator is engaged to handle all of SQLites memory allocation needs. 1195 ** The first pointer (the memory pointer) must be aligned to an 8-byte 1196 ** boundary or subsequent behavior of SQLite will be undefined.</dd> 1197 ** 1198 ** <dt>SQLITE_CONFIG_MUTEX</dt> 1199 ** <dd> ^(This option takes a single argument which is a pointer to an 1200 ** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1201 ** alternative low-level mutex routines to be used in place 1202 ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1203 ** content of the [sqlite3_mutex_methods] structure before the call to 1204 ** [sqlite3_config()] returns. ^If SQLite is compiled with 1205 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1206 ** the entire mutexing subsystem is omitted from the build and hence calls to 1207 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1208 ** return [SQLITE_ERROR].</dd> 1209 ** 1210 ** <dt>SQLITE_CONFIG_GETMUTEX</dt> 1211 ** <dd> ^(This option takes a single argument which is a pointer to an 1212 ** instance of the [sqlite3_mutex_methods] structure. The 1213 ** [sqlite3_mutex_methods] 1214 ** structure is filled with the currently defined mutex routines.)^ 1215 ** This option can be used to overload the default mutex allocation 1216 ** routines with a wrapper used to track mutex usage for performance 1217 ** profiling or testing, for example. ^If SQLite is compiled with 1218 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1219 ** the entire mutexing subsystem is omitted from the build and hence calls to 1220 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1221 ** return [SQLITE_ERROR].</dd> 1222 ** 1223 ** <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1224 ** <dd> ^(This option takes two arguments that determine the default 1225 ** memory allocation for the lookaside memory allocator on each 1226 ** [database connection]. The first argument is the 1227 ** size of each lookaside buffer slot and the second is the number of 1228 ** slots allocated to each database connection.)^ ^(This option sets the 1229 ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1230 ** verb to [sqlite3_db_config()] can be used to change the lookaside 1231 ** configuration on individual connections.)^ </dd> 1232 ** 1233 ** <dt>SQLITE_CONFIG_PCACHE</dt> 1234 ** <dd> ^(This option takes a single argument which is a pointer to 1235 ** an [sqlite3_pcache_methods] object. This object specifies the interface 1236 ** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1237 ** object and uses it for page cache memory allocations.</dd> 1238 ** 1239 ** <dt>SQLITE_CONFIG_GETPCACHE</dt> 1240 ** <dd> ^(This option takes a single argument which is a pointer to an 1241 ** [sqlite3_pcache_methods] object. SQLite copies of the current 1242 ** page cache implementation into that object.)^ </dd> 1243 ** 1244 ** </dl> 1245 */ 1246 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1247 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1248 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1249 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1250 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1251 #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1252 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1253 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1254 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1255 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1256 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1257 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1258 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1259 #define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */ 1260 #define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */ 1261 #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1262 1263 /* 1264 ** CAPI3REF: Configuration Options 1265 ** EXPERIMENTAL 1266 ** 1267 ** These constants are the available integer configuration options that 1268 ** can be passed as the second argument to the [sqlite3_db_config()] interface. 1269 ** 1270 ** New configuration options may be added in future releases of SQLite. 1271 ** Existing configuration options might be discontinued. Applications 1272 ** should check the return code from [sqlite3_db_config()] to make sure that 1273 ** the call worked. ^The [sqlite3_db_config()] interface will return a 1274 ** non-zero [error code] if a discontinued or unsupported configuration option 1275 ** is invoked. 1276 ** 1277 ** <dl> 1278 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1279 ** <dd> ^This option takes three additional arguments that determine the 1280 ** [lookaside memory allocator] configuration for the [database connection]. 1281 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1282 ** pointer to an memory buffer to use for lookaside memory. 1283 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1284 ** may be NULL in which case SQLite will allocate the 1285 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1286 ** size of each lookaside buffer slot. ^The third argument is the number of 1287 ** slots. The size of the buffer in the first argument must be greater than 1288 ** or equal to the product of the second and third arguments. The buffer 1289 ** must be aligned to an 8-byte boundary. ^If the second argument to 1290 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1291 ** rounded down to the next smaller 1292 ** multiple of 8. See also: [SQLITE_CONFIG_LOOKASIDE]</dd> 1293 ** 1294 ** </dl> 1295 */ 1296 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1297 1298 1299 /* 1300 ** CAPI3REF: Enable Or Disable Extended Result Codes 1301 ** 1302 ** ^The sqlite3_extended_result_codes() routine enables or disables the 1303 ** [extended result codes] feature of SQLite. ^The extended result 1304 ** codes are disabled by default for historical compatibility. 1305 */ 1306 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff); 1307 1308 /* 1309 ** CAPI3REF: Last Insert Rowid 1310 ** 1311 ** ^Each entry in an SQLite table has a unique 64-bit signed 1312 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1313 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1314 ** names are not also used by explicitly declared columns. ^If 1315 ** the table has a column of type [INTEGER PRIMARY KEY] then that column 1316 ** is another alias for the rowid. 1317 ** 1318 ** ^This routine returns the [rowid] of the most recent 1319 ** successful [INSERT] into the database from the [database connection] 1320 ** in the first argument. ^If no successful [INSERT]s 1321 ** have ever occurred on that database connection, zero is returned. 1322 ** 1323 ** ^(If an [INSERT] occurs within a trigger, then the [rowid] of the inserted 1324 ** row is returned by this routine as long as the trigger is running. 1325 ** But once the trigger terminates, the value returned by this routine 1326 ** reverts to the last value inserted before the trigger fired.)^ 1327 ** 1328 ** ^An [INSERT] that fails due to a constraint violation is not a 1329 ** successful [INSERT] and does not change the value returned by this 1330 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1331 ** and INSERT OR ABORT make no changes to the return value of this 1332 ** routine when their insertion fails. ^(When INSERT OR REPLACE 1333 ** encounters a constraint violation, it does not fail. The 1334 ** INSERT continues to completion after deleting rows that caused 1335 ** the constraint problem so INSERT OR REPLACE will always change 1336 ** the return value of this interface.)^ 1337 ** 1338 ** ^For the purposes of this routine, an [INSERT] is considered to 1339 ** be successful even if it is subsequently rolled back. 1340 ** 1341 ** This function is accessible to SQL statements via the 1342 ** [last_insert_rowid() SQL function]. 1343 ** 1344 ** If a separate thread performs a new [INSERT] on the same 1345 ** database connection while the [sqlite3_last_insert_rowid()] 1346 ** function is running and thus changes the last insert [rowid], 1347 ** then the value returned by [sqlite3_last_insert_rowid()] is 1348 ** unpredictable and might not equal either the old or the new 1349 ** last insert [rowid]. 1350 */ 1351 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1352 1353 /* 1354 ** CAPI3REF: Count The Number Of Rows Modified 1355 ** 1356 ** ^This function returns the number of database rows that were changed 1357 ** or inserted or deleted by the most recently completed SQL statement 1358 ** on the [database connection] specified by the first parameter. 1359 ** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1360 ** or [DELETE] statement are counted. Auxiliary changes caused by 1361 ** triggers or [foreign key actions] are not counted.)^ Use the 1362 ** [sqlite3_total_changes()] function to find the total number of changes 1363 ** including changes caused by triggers and foreign key actions. 1364 ** 1365 ** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1366 ** are not counted. Only real table changes are counted. 1367 ** 1368 ** ^(A "row change" is a change to a single row of a single table 1369 ** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1370 ** are changed as side effects of [REPLACE] constraint resolution, 1371 ** rollback, ABORT processing, [DROP TABLE], or by any other 1372 ** mechanisms do not count as direct row changes.)^ 1373 ** 1374 ** A "trigger context" is a scope of execution that begins and 1375 ** ends with the script of a [CREATE TRIGGER | trigger]. 1376 ** Most SQL statements are 1377 ** evaluated outside of any trigger. This is the "top level" 1378 ** trigger context. If a trigger fires from the top level, a 1379 ** new trigger context is entered for the duration of that one 1380 ** trigger. Subtriggers create subcontexts for their duration. 1381 ** 1382 ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1383 ** not create a new trigger context. 1384 ** 1385 ** ^This function returns the number of direct row changes in the 1386 ** most recent INSERT, UPDATE, or DELETE statement within the same 1387 ** trigger context. 1388 ** 1389 ** ^Thus, when called from the top level, this function returns the 1390 ** number of changes in the most recent INSERT, UPDATE, or DELETE 1391 ** that also occurred at the top level. ^(Within the body of a trigger, 1392 ** the sqlite3_changes() interface can be called to find the number of 1393 ** changes in the most recently completed INSERT, UPDATE, or DELETE 1394 ** statement within the body of the same trigger. 1395 ** However, the number returned does not include changes 1396 ** caused by subtriggers since those have their own context.)^ 1397 ** 1398 ** See also the [sqlite3_total_changes()] interface, the 1399 ** [count_changes pragma], and the [changes() SQL function]. 1400 ** 1401 ** If a separate thread makes changes on the same database connection 1402 ** while [sqlite3_changes()] is running then the value returned 1403 ** is unpredictable and not meaningful. 1404 */ 1405 SQLITE_API int sqlite3_changes(sqlite3*); 1406 1407 /* 1408 ** CAPI3REF: Total Number Of Rows Modified 1409 ** 1410 ** ^This function returns the number of row changes caused by [INSERT], 1411 ** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1412 ** ^(The count returned by sqlite3_total_changes() includes all changes 1413 ** from all [CREATE TRIGGER | trigger] contexts and changes made by 1414 ** [foreign key actions]. However, 1415 ** the count does not include changes used to implement [REPLACE] constraints, 1416 ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1417 ** count does not include rows of views that fire an [INSTEAD OF trigger], 1418 ** though if the INSTEAD OF trigger makes changes of its own, those changes 1419 ** are counted.)^ 1420 ** ^The sqlite3_total_changes() function counts the changes as soon as 1421 ** the statement that makes them is completed (when the statement handle 1422 ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1423 ** 1424 ** See also the [sqlite3_changes()] interface, the 1425 ** [count_changes pragma], and the [total_changes() SQL function]. 1426 ** 1427 ** If a separate thread makes changes on the same database connection 1428 ** while [sqlite3_total_changes()] is running then the value 1429 ** returned is unpredictable and not meaningful. 1430 */ 1431 SQLITE_API int sqlite3_total_changes(sqlite3*); 1432 1433 /* 1434 ** CAPI3REF: Interrupt A Long-Running Query 1435 ** 1436 ** ^This function causes any pending database operation to abort and 1437 ** return at its earliest opportunity. This routine is typically 1438 ** called in response to a user action such as pressing "Cancel" 1439 ** or Ctrl-C where the user wants a long query operation to halt 1440 ** immediately. 1441 ** 1442 ** ^It is safe to call this routine from a thread different from the 1443 ** thread that is currently running the database operation. But it 1444 ** is not safe to call this routine with a [database connection] that 1445 ** is closed or might close before sqlite3_interrupt() returns. 1446 ** 1447 ** ^If an SQL operation is very nearly finished at the time when 1448 ** sqlite3_interrupt() is called, then it might not have an opportunity 1449 ** to be interrupted and might continue to completion. 1450 ** 1451 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1452 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1453 ** that is inside an explicit transaction, then the entire transaction 1454 ** will be rolled back automatically. 1455 ** 1456 ** ^The sqlite3_interrupt(D) call is in effect until all currently running 1457 ** SQL statements on [database connection] D complete. ^Any new SQL statements 1458 ** that are started after the sqlite3_interrupt() call and before the 1459 ** running statements reaches zero are interrupted as if they had been 1460 ** running prior to the sqlite3_interrupt() call. ^New SQL statements 1461 ** that are started after the running statement count reaches zero are 1462 ** not effected by the sqlite3_interrupt(). 1463 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1464 ** SQL statements is a no-op and has no effect on SQL statements 1465 ** that are started after the sqlite3_interrupt() call returns. 1466 ** 1467 ** If the database connection closes while [sqlite3_interrupt()] 1468 ** is running then bad things will likely happen. 1469 */ 1470 SQLITE_API void sqlite3_interrupt(sqlite3*); 1471 1472 /* 1473 ** CAPI3REF: Determine If An SQL Statement Is Complete 1474 ** 1475 ** These routines are useful during command-line input to determine if the 1476 ** currently entered text seems to form a complete SQL statement or 1477 ** if additional input is needed before sending the text into 1478 ** SQLite for parsing. ^These routines return 1 if the input string 1479 ** appears to be a complete SQL statement. ^A statement is judged to be 1480 ** complete if it ends with a semicolon token and is not a prefix of a 1481 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1482 ** string literals or quoted identifier names or comments are not 1483 ** independent tokens (they are part of the token in which they are 1484 ** embedded) and thus do not count as a statement terminator. ^Whitespace 1485 ** and comments that follow the final semicolon are ignored. 1486 ** 1487 ** ^These routines return 0 if the statement is incomplete. ^If a 1488 ** memory allocation fails, then SQLITE_NOMEM is returned. 1489 ** 1490 ** ^These routines do not parse the SQL statements thus 1491 ** will not detect syntactically incorrect SQL. 1492 ** 1493 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1494 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1495 ** automatically by sqlite3_complete16(). If that initialization fails, 1496 ** then the return value from sqlite3_complete16() will be non-zero 1497 ** regardless of whether or not the input SQL is complete.)^ 1498 ** 1499 ** The input to [sqlite3_complete()] must be a zero-terminated 1500 ** UTF-8 string. 1501 ** 1502 ** The input to [sqlite3_complete16()] must be a zero-terminated 1503 ** UTF-16 string in native byte order. 1504 */ 1505 SQLITE_API int sqlite3_complete(const char *sql); 1506 SQLITE_API int sqlite3_complete16(const void *sql); 1507 1508 /* 1509 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1510 ** 1511 ** ^This routine sets a callback function that might be invoked whenever 1512 ** an attempt is made to open a database table that another thread 1513 ** or process has locked. 1514 ** 1515 ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1516 ** is returned immediately upon encountering the lock. ^If the busy callback 1517 ** is not NULL, then the callback might be invoked with two arguments. 1518 ** 1519 ** ^The first argument to the busy handler is a copy of the void* pointer which 1520 ** is the third argument to sqlite3_busy_handler(). ^The second argument to 1521 ** the busy handler callback is the number of times that the busy handler has 1522 ** been invoked for this locking event. ^If the 1523 ** busy callback returns 0, then no additional attempts are made to 1524 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1525 ** ^If the callback returns non-zero, then another attempt 1526 ** is made to open the database for reading and the cycle repeats. 1527 ** 1528 ** The presence of a busy handler does not guarantee that it will be invoked 1529 ** when there is lock contention. ^If SQLite determines that invoking the busy 1530 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1531 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1532 ** Consider a scenario where one process is holding a read lock that 1533 ** it is trying to promote to a reserved lock and 1534 ** a second process is holding a reserved lock that it is trying 1535 ** to promote to an exclusive lock. The first process cannot proceed 1536 ** because it is blocked by the second and the second process cannot 1537 ** proceed because it is blocked by the first. If both processes 1538 ** invoke the busy handlers, neither will make any progress. Therefore, 1539 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1540 ** will induce the first process to release its read lock and allow 1541 ** the second process to proceed. 1542 ** 1543 ** ^The default busy callback is NULL. 1544 ** 1545 ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1546 ** when SQLite is in the middle of a large transaction where all the 1547 ** changes will not fit into the in-memory cache. SQLite will 1548 ** already hold a RESERVED lock on the database file, but it needs 1549 ** to promote this lock to EXCLUSIVE so that it can spill cache 1550 ** pages into the database file without harm to concurrent 1551 ** readers. ^If it is unable to promote the lock, then the in-memory 1552 ** cache will be left in an inconsistent state and so the error 1553 ** code is promoted from the relatively benign [SQLITE_BUSY] to 1554 ** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 1555 ** forces an automatic rollback of the changes. See the 1556 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1557 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1558 ** this is important. 1559 ** 1560 ** ^(There can only be a single busy handler defined for each 1561 ** [database connection]. Setting a new busy handler clears any 1562 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 1563 ** will also set or clear the busy handler. 1564 ** 1565 ** The busy callback should not take any actions which modify the 1566 ** database connection that invoked the busy handler. Any such actions 1567 ** result in undefined behavior. 1568 ** 1569 ** A busy handler must not close the database connection 1570 ** or [prepared statement] that invoked the busy handler. 1571 */ 1572 SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1573 1574 /* 1575 ** CAPI3REF: Set A Busy Timeout 1576 ** 1577 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1578 ** for a specified amount of time when a table is locked. ^The handler 1579 ** will sleep multiple times until at least "ms" milliseconds of sleeping 1580 ** have accumulated. ^After at least "ms" milliseconds of sleeping, 1581 ** the handler returns 0 which causes [sqlite3_step()] to return 1582 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1583 ** 1584 ** ^Calling this routine with an argument less than or equal to zero 1585 ** turns off all busy handlers. 1586 ** 1587 ** ^(There can only be a single busy handler for a particular 1588 ** [database connection] any any given moment. If another busy handler 1589 ** was defined (using [sqlite3_busy_handler()]) prior to calling 1590 ** this routine, that other busy handler is cleared.)^ 1591 */ 1592 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms); 1593 1594 /* 1595 ** CAPI3REF: Convenience Routines For Running Queries 1596 ** 1597 ** Definition: A <b>result table</b> is memory data structure created by the 1598 ** [sqlite3_get_table()] interface. A result table records the 1599 ** complete query results from one or more queries. 1600 ** 1601 ** The table conceptually has a number of rows and columns. But 1602 ** these numbers are not part of the result table itself. These 1603 ** numbers are obtained separately. Let N be the number of rows 1604 ** and M be the number of columns. 1605 ** 1606 ** A result table is an array of pointers to zero-terminated UTF-8 strings. 1607 ** There are (N+1)*M elements in the array. The first M pointers point 1608 ** to zero-terminated strings that contain the names of the columns. 1609 ** The remaining entries all point to query results. NULL values result 1610 ** in NULL pointers. All other values are in their UTF-8 zero-terminated 1611 ** string representation as returned by [sqlite3_column_text()]. 1612 ** 1613 ** A result table might consist of one or more memory allocations. 1614 ** It is not safe to pass a result table directly to [sqlite3_free()]. 1615 ** A result table should be deallocated using [sqlite3_free_table()]. 1616 ** 1617 ** As an example of the result table format, suppose a query result 1618 ** is as follows: 1619 ** 1620 ** <blockquote><pre> 1621 ** Name | Age 1622 ** ----------------------- 1623 ** Alice | 43 1624 ** Bob | 28 1625 ** Cindy | 21 1626 ** </pre></blockquote> 1627 ** 1628 ** There are two column (M==2) and three rows (N==3). Thus the 1629 ** result table has 8 entries. Suppose the result table is stored 1630 ** in an array names azResult. Then azResult holds this content: 1631 ** 1632 ** <blockquote><pre> 1633 ** azResult[0] = "Name"; 1634 ** azResult[1] = "Age"; 1635 ** azResult[2] = "Alice"; 1636 ** azResult[3] = "43"; 1637 ** azResult[4] = "Bob"; 1638 ** azResult[5] = "28"; 1639 ** azResult[6] = "Cindy"; 1640 ** azResult[7] = "21"; 1641 ** </pre></blockquote> 1642 ** 1643 ** ^The sqlite3_get_table() function evaluates one or more 1644 ** semicolon-separated SQL statements in the zero-terminated UTF-8 1645 ** string of its 2nd parameter and returns a result table to the 1646 ** pointer given in its 3rd parameter. 1647 ** 1648 ** After the application has finished with the result from sqlite3_get_table(), 1649 ** it should pass the result table pointer to sqlite3_free_table() in order to 1650 ** release the memory that was malloced. Because of the way the 1651 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1652 ** function must not try to call [sqlite3_free()] directly. Only 1653 ** [sqlite3_free_table()] is able to release the memory properly and safely. 1654 ** 1655 ** ^(The sqlite3_get_table() interface is implemented as a wrapper around 1656 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 1657 ** to any internal data structures of SQLite. It uses only the public 1658 ** interface defined here. As a consequence, errors that occur in the 1659 ** wrapper layer outside of the internal [sqlite3_exec()] call are not 1660 ** reflected in subsequent calls to [sqlite3_errcode()] or 1661 ** [sqlite3_errmsg()].)^ 1662 */ 1663 SQLITE_API int sqlite3_get_table( 1664 sqlite3 *db, /* An open database */ 1665 const char *zSql, /* SQL to be evaluated */ 1666 char ***pazResult, /* Results of the query */ 1667 int *pnRow, /* Number of result rows written here */ 1668 int *pnColumn, /* Number of result columns written here */ 1669 char **pzErrmsg /* Error msg written here */ 1670 ); 1671 SQLITE_API void sqlite3_free_table(char **result); 1672 1673 /* 1674 ** CAPI3REF: Formatted String Printing Functions 1675 ** 1676 ** These routines are work-alikes of the "printf()" family of functions 1677 ** from the standard C library. 1678 ** 1679 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 1680 ** results into memory obtained from [sqlite3_malloc()]. 1681 ** The strings returned by these two routines should be 1682 ** released by [sqlite3_free()]. ^Both routines return a 1683 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 1684 ** memory to hold the resulting string. 1685 ** 1686 ** ^(In sqlite3_snprintf() routine is similar to "snprintf()" from 1687 ** the standard C library. The result is written into the 1688 ** buffer supplied as the second parameter whose size is given by 1689 ** the first parameter. Note that the order of the 1690 ** first two parameters is reversed from snprintf().)^ This is an 1691 ** historical accident that cannot be fixed without breaking 1692 ** backwards compatibility. ^(Note also that sqlite3_snprintf() 1693 ** returns a pointer to its buffer instead of the number of 1694 ** characters actually written into the buffer.)^ We admit that 1695 ** the number of characters written would be a more useful return 1696 ** value but we cannot change the implementation of sqlite3_snprintf() 1697 ** now without breaking compatibility. 1698 ** 1699 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 1700 ** guarantees that the buffer is always zero-terminated. ^The first 1701 ** parameter "n" is the total size of the buffer, including space for 1702 ** the zero terminator. So the longest string that can be completely 1703 ** written will be n-1 characters. 1704 ** 1705 ** These routines all implement some additional formatting 1706 ** options that are useful for constructing SQL statements. 1707 ** All of the usual printf() formatting options apply. In addition, there 1708 ** is are "%q", "%Q", and "%z" options. 1709 ** 1710 ** ^(The %q option works like %s in that it substitutes a null-terminated 1711 ** string from the argument list. But %q also doubles every '\'' character. 1712 ** %q is designed for use inside a string literal.)^ By doubling each '\'' 1713 ** character it escapes that character and allows it to be inserted into 1714 ** the string. 1715 ** 1716 ** For example, assume the string variable zText contains text as follows: 1717 ** 1718 ** <blockquote><pre> 1719 ** char *zText = "It's a happy day!"; 1720 ** </pre></blockquote> 1721 ** 1722 ** One can use this text in an SQL statement as follows: 1723 ** 1724 ** <blockquote><pre> 1725 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 1726 ** sqlite3_exec(db, zSQL, 0, 0, 0); 1727 ** sqlite3_free(zSQL); 1728 ** </pre></blockquote> 1729 ** 1730 ** Because the %q format string is used, the '\'' character in zText 1731 ** is escaped and the SQL generated is as follows: 1732 ** 1733 ** <blockquote><pre> 1734 ** INSERT INTO table1 VALUES('It''s a happy day!') 1735 ** </pre></blockquote> 1736 ** 1737 ** This is correct. Had we used %s instead of %q, the generated SQL 1738 ** would have looked like this: 1739 ** 1740 ** <blockquote><pre> 1741 ** INSERT INTO table1 VALUES('It's a happy day!'); 1742 ** </pre></blockquote> 1743 ** 1744 ** This second example is an SQL syntax error. As a general rule you should 1745 ** always use %q instead of %s when inserting text into a string literal. 1746 ** 1747 ** ^(The %Q option works like %q except it also adds single quotes around 1748 ** the outside of the total string. Additionally, if the parameter in the 1749 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 1750 ** single quotes).)^ So, for example, one could say: 1751 ** 1752 ** <blockquote><pre> 1753 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 1754 ** sqlite3_exec(db, zSQL, 0, 0, 0); 1755 ** sqlite3_free(zSQL); 1756 ** </pre></blockquote> 1757 ** 1758 ** The code above will render a correct SQL statement in the zSQL 1759 ** variable even if the zText variable is a NULL pointer. 1760 ** 1761 ** ^(The "%z" formatting option works like "%s" but with the 1762 ** addition that after the string has been read and copied into 1763 ** the result, [sqlite3_free()] is called on the input string.)^ 1764 */ 1765 SQLITE_API char *sqlite3_mprintf(const char*,...); 1766 SQLITE_API char *sqlite3_vmprintf(const char*, va_list); 1767 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...); 1768 1769 /* 1770 ** CAPI3REF: Memory Allocation Subsystem 1771 ** 1772 ** The SQLite core uses these three routines for all of its own 1773 ** internal memory allocation needs. "Core" in the previous sentence 1774 ** does not include operating-system specific VFS implementation. The 1775 ** Windows VFS uses native malloc() and free() for some operations. 1776 ** 1777 ** ^The sqlite3_malloc() routine returns a pointer to a block 1778 ** of memory at least N bytes in length, where N is the parameter. 1779 ** ^If sqlite3_malloc() is unable to obtain sufficient free 1780 ** memory, it returns a NULL pointer. ^If the parameter N to 1781 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 1782 ** a NULL pointer. 1783 ** 1784 ** ^Calling sqlite3_free() with a pointer previously returned 1785 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 1786 ** that it might be reused. ^The sqlite3_free() routine is 1787 ** a no-op if is called with a NULL pointer. Passing a NULL pointer 1788 ** to sqlite3_free() is harmless. After being freed, memory 1789 ** should neither be read nor written. Even reading previously freed 1790 ** memory might result in a segmentation fault or other severe error. 1791 ** Memory corruption, a segmentation fault, or other severe error 1792 ** might result if sqlite3_free() is called with a non-NULL pointer that 1793 ** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 1794 ** 1795 ** ^(The sqlite3_realloc() interface attempts to resize a 1796 ** prior memory allocation to be at least N bytes, where N is the 1797 ** second parameter. The memory allocation to be resized is the first 1798 ** parameter.)^ ^ If the first parameter to sqlite3_realloc() 1799 ** is a NULL pointer then its behavior is identical to calling 1800 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 1801 ** ^If the second parameter to sqlite3_realloc() is zero or 1802 ** negative then the behavior is exactly the same as calling 1803 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 1804 ** ^sqlite3_realloc() returns a pointer to a memory allocation 1805 ** of at least N bytes in size or NULL if sufficient memory is unavailable. 1806 ** ^If M is the size of the prior allocation, then min(N,M) bytes 1807 ** of the prior allocation are copied into the beginning of buffer returned 1808 ** by sqlite3_realloc() and the prior allocation is freed. 1809 ** ^If sqlite3_realloc() returns NULL, then the prior allocation 1810 ** is not freed. 1811 ** 1812 ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 1813 ** is always aligned to at least an 8 byte boundary. 1814 ** 1815 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define 1816 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 1817 ** implementation of these routines to be omitted. That capability 1818 ** is no longer provided. Only built-in memory allocators can be used. 1819 ** 1820 ** The Windows OS interface layer calls 1821 ** the system malloc() and free() directly when converting 1822 ** filenames between the UTF-8 encoding used by SQLite 1823 ** and whatever filename encoding is used by the particular Windows 1824 ** installation. Memory allocation errors are detected, but 1825 ** they are reported back as [SQLITE_CANTOPEN] or 1826 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 1827 ** 1828 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 1829 ** must be either NULL or else pointers obtained from a prior 1830 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 1831 ** not yet been released. 1832 ** 1833 ** The application must not read or write any part of 1834 ** a block of memory after it has been released using 1835 ** [sqlite3_free()] or [sqlite3_realloc()]. 1836 */ 1837 SQLITE_API void *sqlite3_malloc(int); 1838 SQLITE_API void *sqlite3_realloc(void*, int); 1839 SQLITE_API void sqlite3_free(void*); 1840 1841 /* 1842 ** CAPI3REF: Memory Allocator Statistics 1843 ** 1844 ** SQLite provides these two interfaces for reporting on the status 1845 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 1846 ** routines, which form the built-in memory allocation subsystem. 1847 ** 1848 ** ^The [sqlite3_memory_used()] routine returns the number of bytes 1849 ** of memory currently outstanding (malloced but not freed). 1850 ** ^The [sqlite3_memory_highwater()] routine returns the maximum 1851 ** value of [sqlite3_memory_used()] since the high-water mark 1852 ** was last reset. ^The values returned by [sqlite3_memory_used()] and 1853 ** [sqlite3_memory_highwater()] include any overhead 1854 ** added by SQLite in its implementation of [sqlite3_malloc()], 1855 ** but not overhead added by the any underlying system library 1856 ** routines that [sqlite3_malloc()] may call. 1857 ** 1858 ** ^The memory high-water mark is reset to the current value of 1859 ** [sqlite3_memory_used()] if and only if the parameter to 1860 ** [sqlite3_memory_highwater()] is true. ^The value returned 1861 ** by [sqlite3_memory_highwater(1)] is the high-water mark 1862 ** prior to the reset. 1863 */ 1864 SQLITE_API sqlite3_int64 sqlite3_memory_used(void); 1865 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 1866 1867 /* 1868 ** CAPI3REF: Pseudo-Random Number Generator 1869 ** 1870 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 1871 ** select random [ROWID | ROWIDs] when inserting new records into a table that 1872 ** already uses the largest possible [ROWID]. The PRNG is also used for 1873 ** the build-in random() and randomblob() SQL functions. This interface allows 1874 ** applications to access the same PRNG for other purposes. 1875 ** 1876 ** ^A call to this routine stores N bytes of randomness into buffer P. 1877 ** 1878 ** ^The first time this routine is invoked (either internally or by 1879 ** the application) the PRNG is seeded using randomness obtained 1880 ** from the xRandomness method of the default [sqlite3_vfs] object. 1881 ** ^On all subsequent invocations, the pseudo-randomness is generated 1882 ** internally and without recourse to the [sqlite3_vfs] xRandomness 1883 ** method. 1884 */ 1885 SQLITE_API void sqlite3_randomness(int N, void *P); 1886 1887 /* 1888 ** CAPI3REF: Compile-Time Authorization Callbacks 1889 ** 1890 ** ^This routine registers a authorizer callback with a particular 1891 ** [database connection], supplied in the first argument. 1892 ** ^The authorizer callback is invoked as SQL statements are being compiled 1893 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 1894 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 1895 ** points during the compilation process, as logic is being created 1896 ** to perform various actions, the authorizer callback is invoked to 1897 ** see if those actions are allowed. ^The authorizer callback should 1898 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 1899 ** specific action but allow the SQL statement to continue to be 1900 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 1901 ** rejected with an error. ^If the authorizer callback returns 1902 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 1903 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered 1904 ** the authorizer will fail with an error message. 1905 ** 1906 ** When the callback returns [SQLITE_OK], that means the operation 1907 ** requested is ok. ^When the callback returns [SQLITE_DENY], the 1908 ** [sqlite3_prepare_v2()] or equivalent call that triggered the 1909 ** authorizer will fail with an error message explaining that 1910 ** access is denied. 1911 ** 1912 ** ^The first parameter to the authorizer callback is a copy of the third 1913 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 1914 ** to the callback is an integer [SQLITE_COPY | action code] that specifies 1915 ** the particular action to be authorized. ^The third through sixth parameters 1916 ** to the callback are zero-terminated strings that contain additional 1917 ** details about the action to be authorized. 1918 ** 1919 ** ^If the action code is [SQLITE_READ] 1920 ** and the callback returns [SQLITE_IGNORE] then the 1921 ** [prepared statement] statement is constructed to substitute 1922 ** a NULL value in place of the table column that would have 1923 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 1924 ** return can be used to deny an untrusted user access to individual 1925 ** columns of a table. 1926 ** ^If the action code is [SQLITE_DELETE] and the callback returns 1927 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 1928 ** [truncate optimization] is disabled and all rows are deleted individually. 1929 ** 1930 ** An authorizer is used when [sqlite3_prepare | preparing] 1931 ** SQL statements from an untrusted source, to ensure that the SQL statements 1932 ** do not try to access data they are not allowed to see, or that they do not 1933 ** try to execute malicious statements that damage the database. For 1934 ** example, an application may allow a user to enter arbitrary 1935 ** SQL queries for evaluation by a database. But the application does 1936 ** not want the user to be able to make arbitrary changes to the 1937 ** database. An authorizer could then be put in place while the 1938 ** user-entered SQL is being [sqlite3_prepare | prepared] that 1939 ** disallows everything except [SELECT] statements. 1940 ** 1941 ** Applications that need to process SQL from untrusted sources 1942 ** might also consider lowering resource limits using [sqlite3_limit()] 1943 ** and limiting database size using the [max_page_count] [PRAGMA] 1944 ** in addition to using an authorizer. 1945 ** 1946 ** ^(Only a single authorizer can be in place on a database connection 1947 ** at a time. Each call to sqlite3_set_authorizer overrides the 1948 ** previous call.)^ ^Disable the authorizer by installing a NULL callback. 1949 ** The authorizer is disabled by default. 1950 ** 1951 ** The authorizer callback must not do anything that will modify 1952 ** the database connection that invoked the authorizer callback. 1953 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 1954 ** database connections for the meaning of "modify" in this paragraph. 1955 ** 1956 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 1957 ** statement might be re-prepared during [sqlite3_step()] due to a 1958 ** schema change. Hence, the application should ensure that the 1959 ** correct authorizer callback remains in place during the [sqlite3_step()]. 1960 ** 1961 ** ^Note that the authorizer callback is invoked only during 1962 ** [sqlite3_prepare()] or its variants. Authorization is not 1963 ** performed during statement evaluation in [sqlite3_step()], unless 1964 ** as stated in the previous paragraph, sqlite3_step() invokes 1965 ** sqlite3_prepare_v2() to reprepare a statement after a schema change. 1966 */ 1967 SQLITE_API int sqlite3_set_authorizer( 1968 sqlite3*, 1969 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 1970 void *pUserData 1971 ); 1972 1973 /* 1974 ** CAPI3REF: Authorizer Return Codes 1975 ** 1976 ** The [sqlite3_set_authorizer | authorizer callback function] must 1977 ** return either [SQLITE_OK] or one of these two constants in order 1978 ** to signal SQLite whether or not the action is permitted. See the 1979 ** [sqlite3_set_authorizer | authorizer documentation] for additional 1980 ** information. 1981 */ 1982 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 1983 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 1984 1985 /* 1986 ** CAPI3REF: Authorizer Action Codes 1987 ** 1988 ** The [sqlite3_set_authorizer()] interface registers a callback function 1989 ** that is invoked to authorize certain SQL statement actions. The 1990 ** second parameter to the callback is an integer code that specifies 1991 ** what action is being authorized. These are the integer action codes that 1992 ** the authorizer callback may be passed. 1993 ** 1994 ** These action code values signify what kind of operation is to be 1995 ** authorized. The 3rd and 4th parameters to the authorization 1996 ** callback function will be parameters or NULL depending on which of these 1997 ** codes is used as the second parameter. ^(The 5th parameter to the 1998 ** authorizer callback is the name of the database ("main", "temp", 1999 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2000 ** is the name of the inner-most trigger or view that is responsible for 2001 ** the access attempt or NULL if this access attempt is directly from 2002 ** top-level SQL code. 2003 */ 2004 /******************************************* 3rd ************ 4th ***********/ 2005 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2006 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2007 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2008 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2009 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2010 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2011 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2012 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2013 #define SQLITE_DELETE 9 /* Table Name NULL */ 2014 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2015 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2016 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2017 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2018 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2019 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2020 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2021 #define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2022 #define SQLITE_INSERT 18 /* Table Name NULL */ 2023 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2024 #define SQLITE_READ 20 /* Table Name Column Name */ 2025 #define SQLITE_SELECT 21 /* NULL NULL */ 2026 #define SQLITE_TRANSACTION 22 /* Operation NULL */ 2027 #define SQLITE_UPDATE 23 /* Table Name Column Name */ 2028 #define SQLITE_ATTACH 24 /* Filename NULL */ 2029 #define SQLITE_DETACH 25 /* Database Name NULL */ 2030 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2031 #define SQLITE_REINDEX 27 /* Index Name NULL */ 2032 #define SQLITE_ANALYZE 28 /* Table Name NULL */ 2033 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2034 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2035 #define SQLITE_FUNCTION 31 /* NULL Function Name */ 2036 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2037 #define SQLITE_COPY 0 /* No longer used */ 2038 2039 /* 2040 ** CAPI3REF: Tracing And Profiling Functions 2041 ** EXPERIMENTAL 2042 ** 2043 ** These routines register callback functions that can be used for 2044 ** tracing and profiling the execution of SQL statements. 2045 ** 2046 ** ^The callback function registered by sqlite3_trace() is invoked at 2047 ** various times when an SQL statement is being run by [sqlite3_step()]. 2048 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2049 ** SQL statement text as the statement first begins executing. 2050 ** ^(Additional sqlite3_trace() callbacks might occur 2051 ** as each triggered subprogram is entered. The callbacks for triggers 2052 ** contain a UTF-8 SQL comment that identifies the trigger.)^ 2053 ** 2054 ** ^The callback function registered by sqlite3_profile() is invoked 2055 ** as each SQL statement finishes. ^The profile callback contains 2056 ** the original statement text and an estimate of wall-clock time 2057 ** of how long that statement took to run. 2058 */ 2059 SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2060 SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2061 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2062 2063 /* 2064 ** CAPI3REF: Query Progress Callbacks 2065 ** 2066 ** ^This routine configures a callback function - the 2067 ** progress callback - that is invoked periodically during long 2068 ** running calls to [sqlite3_exec()], [sqlite3_step()] and 2069 ** [sqlite3_get_table()]. An example use for this 2070 ** interface is to keep a GUI updated during a large query. 2071 ** 2072 ** ^If the progress callback returns non-zero, the operation is 2073 ** interrupted. This feature can be used to implement a 2074 ** "Cancel" button on a GUI progress dialog box. 2075 ** 2076 ** The progress handler must not do anything that will modify 2077 ** the database connection that invoked the progress handler. 2078 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2079 ** database connections for the meaning of "modify" in this paragraph. 2080 ** 2081 */ 2082 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2083 2084 /* 2085 ** CAPI3REF: Opening A New Database Connection 2086 ** 2087 ** ^These routines open an SQLite database file whose name is given by the 2088 ** filename argument. ^The filename argument is interpreted as UTF-8 for 2089 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2090 ** order for sqlite3_open16(). ^(A [database connection] handle is usually 2091 ** returned in *ppDb, even if an error occurs. The only exception is that 2092 ** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2093 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2094 ** object.)^ ^(If the database is opened (and/or created) successfully, then 2095 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2096 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2097 ** an English language description of the error following a failure of any 2098 ** of the sqlite3_open() routines. 2099 ** 2100 ** ^The default encoding for the database will be UTF-8 if 2101 ** sqlite3_open() or sqlite3_open_v2() is called and 2102 ** UTF-16 in the native byte order if sqlite3_open16() is used. 2103 ** 2104 ** Whether or not an error occurs when it is opened, resources 2105 ** associated with the [database connection] handle should be released by 2106 ** passing it to [sqlite3_close()] when it is no longer required. 2107 ** 2108 ** The sqlite3_open_v2() interface works like sqlite3_open() 2109 ** except that it accepts two additional parameters for additional control 2110 ** over the new database connection. ^(The flags parameter to 2111 ** sqlite3_open_v2() can take one of 2112 ** the following three values, optionally combined with the 2113 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2114 ** and/or [SQLITE_OPEN_PRIVATECACHE] flags:)^ 2115 ** 2116 ** <dl> 2117 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2118 ** <dd>The database is opened in read-only mode. If the database does not 2119 ** already exist, an error is returned.</dd>)^ 2120 ** 2121 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2122 ** <dd>The database is opened for reading and writing if possible, or reading 2123 ** only if the file is write protected by the operating system. In either 2124 ** case the database must already exist, otherwise an error is returned.</dd>)^ 2125 ** 2126 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2127 ** <dd>The database is opened for reading and writing, and is creates it if 2128 ** it does not already exist. This is the behavior that is always used for 2129 ** sqlite3_open() and sqlite3_open16().</dd>)^ 2130 ** </dl> 2131 ** 2132 ** If the 3rd parameter to sqlite3_open_v2() is not one of the 2133 ** combinations shown above or one of the combinations shown above combined 2134 ** with the [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], 2135 ** [SQLITE_OPEN_SHAREDCACHE] and/or [SQLITE_OPEN_SHAREDCACHE] flags, 2136 ** then the behavior is undefined. 2137 ** 2138 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2139 ** opens in the multi-thread [threading mode] as long as the single-thread 2140 ** mode has not been set at compile-time or start-time. ^If the 2141 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2142 ** in the serialized [threading mode] unless single-thread was 2143 ** previously selected at compile-time or start-time. 2144 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2145 ** eligible to use [shared cache mode], regardless of whether or not shared 2146 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2147 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2148 ** participate in [shared cache mode] even if it is enabled. 2149 ** 2150 ** ^If the filename is ":memory:", then a private, temporary in-memory database 2151 ** is created for the connection. ^This in-memory database will vanish when 2152 ** the database connection is closed. Future versions of SQLite might 2153 ** make use of additional special filenames that begin with the ":" character. 2154 ** It is recommended that when a database filename actually does begin with 2155 ** a ":" character you should prefix the filename with a pathname such as 2156 ** "./" to avoid ambiguity. 2157 ** 2158 ** ^If the filename is an empty string, then a private, temporary 2159 ** on-disk database will be created. ^This private database will be 2160 ** automatically deleted as soon as the database connection is closed. 2161 ** 2162 ** ^The fourth parameter to sqlite3_open_v2() is the name of the 2163 ** [sqlite3_vfs] object that defines the operating system interface that 2164 ** the new database connection should use. ^If the fourth parameter is 2165 ** a NULL pointer then the default [sqlite3_vfs] object is used. 2166 ** 2167 ** <b>Note to Windows users:</b> The encoding used for the filename argument 2168 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2169 ** codepage is currently defined. Filenames containing international 2170 ** characters must be converted to UTF-8 prior to passing them into 2171 ** sqlite3_open() or sqlite3_open_v2(). 2172 */ 2173 SQLITE_API int sqlite3_open( 2174 const char *filename, /* Database filename (UTF-8) */ 2175 sqlite3 **ppDb /* OUT: SQLite db handle */ 2176 ); 2177 SQLITE_API int sqlite3_open16( 2178 const void *filename, /* Database filename (UTF-16) */ 2179 sqlite3 **ppDb /* OUT: SQLite db handle */ 2180 ); 2181 SQLITE_API int sqlite3_open_v2( 2182 const char *filename, /* Database filename (UTF-8) */ 2183 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2184 int flags, /* Flags */ 2185 const char *zVfs /* Name of VFS module to use */ 2186 ); 2187 2188 /* 2189 ** CAPI3REF: Error Codes And Messages 2190 ** 2191 ** ^The sqlite3_errcode() interface returns the numeric [result code] or 2192 ** [extended result code] for the most recent failed sqlite3_* API call 2193 ** associated with a [database connection]. If a prior API call failed 2194 ** but the most recent API call succeeded, the return value from 2195 ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2196 ** interface is the same except that it always returns the 2197 ** [extended result code] even when extended result codes are 2198 ** disabled. 2199 ** 2200 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2201 ** text that describes the error, as either UTF-8 or UTF-16 respectively. 2202 ** ^(Memory to hold the error message string is managed internally. 2203 ** The application does not need to worry about freeing the result. 2204 ** However, the error string might be overwritten or deallocated by 2205 ** subsequent calls to other SQLite interface functions.)^ 2206 ** 2207 ** When the serialized [threading mode] is in use, it might be the 2208 ** case that a second error occurs on a separate thread in between 2209 ** the time of the first error and the call to these interfaces. 2210 ** When that happens, the second error will be reported since these 2211 ** interfaces always report the most recent result. To avoid 2212 ** this, each thread can obtain exclusive use of the [database connection] D 2213 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2214 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2215 ** all calls to the interfaces listed here are completed. 2216 ** 2217 ** If an interface fails with SQLITE_MISUSE, that means the interface 2218 ** was invoked incorrectly by the application. In that case, the 2219 ** error code and message may or may not be set. 2220 */ 2221 SQLITE_API int sqlite3_errcode(sqlite3 *db); 2222 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db); 2223 SQLITE_API const char *sqlite3_errmsg(sqlite3*); 2224 SQLITE_API const void *sqlite3_errmsg16(sqlite3*); 2225 2226 /* 2227 ** CAPI3REF: SQL Statement Object 2228 ** KEYWORDS: {prepared statement} {prepared statements} 2229 ** 2230 ** An instance of this object represents a single SQL statement. 2231 ** This object is variously known as a "prepared statement" or a 2232 ** "compiled SQL statement" or simply as a "statement". 2233 ** 2234 ** The life of a statement object goes something like this: 2235 ** 2236 ** <ol> 2237 ** <li> Create the object using [sqlite3_prepare_v2()] or a related 2238 ** function. 2239 ** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2240 ** interfaces. 2241 ** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2242 ** <li> Reset the statement using [sqlite3_reset()] then go back 2243 ** to step 2. Do this zero or more times. 2244 ** <li> Destroy the object using [sqlite3_finalize()]. 2245 ** </ol> 2246 ** 2247 ** Refer to documentation on individual methods above for additional 2248 ** information. 2249 */ 2250 typedef struct sqlite3_stmt sqlite3_stmt; 2251 2252 /* 2253 ** CAPI3REF: Run-time Limits 2254 ** 2255 ** ^(This interface allows the size of various constructs to be limited 2256 ** on a connection by connection basis. The first parameter is the 2257 ** [database connection] whose limit is to be set or queried. The 2258 ** second parameter is one of the [limit categories] that define a 2259 ** class of constructs to be size limited. The third parameter is the 2260 ** new limit for that construct. The function returns the old limit.)^ 2261 ** 2262 ** ^If the new limit is a negative number, the limit is unchanged. 2263 ** ^(For the limit category of SQLITE_LIMIT_XYZ there is a 2264 ** [limits | hard upper bound] 2265 ** set by a compile-time C preprocessor macro named 2266 ** [limits | SQLITE_MAX_XYZ]. 2267 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2268 ** ^Attempts to increase a limit above its hard upper bound are 2269 ** silently truncated to the hard upper bound. 2270 ** 2271 ** Run-time limits are intended for use in applications that manage 2272 ** both their own internal database and also databases that are controlled 2273 ** by untrusted external sources. An example application might be a 2274 ** web browser that has its own databases for storing history and 2275 ** separate databases controlled by JavaScript applications downloaded 2276 ** off the Internet. The internal databases can be given the 2277 ** large, default limits. Databases managed by external sources can 2278 ** be given much smaller limits designed to prevent a denial of service 2279 ** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2280 ** interface to further control untrusted SQL. The size of the database 2281 ** created by an untrusted script can be contained using the 2282 ** [max_page_count] [PRAGMA]. 2283 ** 2284 ** New run-time limit categories may be added in future releases. 2285 */ 2286 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal); 2287 2288 /* 2289 ** CAPI3REF: Run-Time Limit Categories 2290 ** KEYWORDS: {limit category} {*limit categories} 2291 ** 2292 ** These constants define various performance limits 2293 ** that can be lowered at run-time using [sqlite3_limit()]. 2294 ** The synopsis of the meanings of the various limits is shown below. 2295 ** Additional information is available at [limits | Limits in SQLite]. 2296 ** 2297 ** <dl> 2298 ** ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2299 ** <dd>The maximum size of any string or BLOB or table row.<dd>)^ 2300 ** 2301 ** ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2302 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2303 ** 2304 ** ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2305 ** <dd>The maximum number of columns in a table definition or in the 2306 ** result set of a [SELECT] or the maximum number of columns in an index 2307 ** or in an ORDER BY or GROUP BY clause.</dd>)^ 2308 ** 2309 ** ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2310 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2311 ** 2312 ** ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2313 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2314 ** 2315 ** ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2316 ** <dd>The maximum number of instructions in a virtual machine program 2317 ** used to implement an SQL statement.</dd>)^ 2318 ** 2319 ** ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2320 ** <dd>The maximum number of arguments on a function.</dd>)^ 2321 ** 2322 ** ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2323 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2324 ** 2325 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2326 ** <dd>The maximum length of the pattern argument to the [LIKE] or 2327 ** [GLOB] operators.</dd>)^ 2328 ** 2329 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2330 ** <dd>The maximum number of variables in an SQL statement that can 2331 ** be bound.</dd>)^ 2332 ** 2333 ** ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2334 ** <dd>The maximum depth of recursion for triggers.</dd>)^ 2335 ** </dl> 2336 */ 2337 #define SQLITE_LIMIT_LENGTH 0 2338 #define SQLITE_LIMIT_SQL_LENGTH 1 2339 #define SQLITE_LIMIT_COLUMN 2 2340 #define SQLITE_LIMIT_EXPR_DEPTH 3 2341 #define SQLITE_LIMIT_COMPOUND_SELECT 4 2342 #define SQLITE_LIMIT_VDBE_OP 5 2343 #define SQLITE_LIMIT_FUNCTION_ARG 6 2344 #define SQLITE_LIMIT_ATTACHED 7 2345 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2346 #define SQLITE_LIMIT_VARIABLE_NUMBER 9 2347 #define SQLITE_LIMIT_TRIGGER_DEPTH 10 2348 2349 /* 2350 ** CAPI3REF: Compiling An SQL Statement 2351 ** KEYWORDS: {SQL statement compiler} 2352 ** 2353 ** To execute an SQL query, it must first be compiled into a byte-code 2354 ** program using one of these routines. 2355 ** 2356 ** The first argument, "db", is a [database connection] obtained from a 2357 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2358 ** [sqlite3_open16()]. The database connection must not have been closed. 2359 ** 2360 ** The second argument, "zSql", is the statement to be compiled, encoded 2361 ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2362 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2363 ** use UTF-16. 2364 ** 2365 ** ^If the nByte argument is less than zero, then zSql is read up to the 2366 ** first zero terminator. ^If nByte is non-negative, then it is the maximum 2367 ** number of bytes read from zSql. ^When nByte is non-negative, the 2368 ** zSql string ends at either the first '\000' or '\u0000' character or 2369 ** the nByte-th byte, whichever comes first. If the caller knows 2370 ** that the supplied string is nul-terminated, then there is a small 2371 ** performance advantage to be gained by passing an nByte parameter that 2372 ** is equal to the number of bytes in the input string <i>including</i> 2373 ** the nul-terminator bytes. 2374 ** 2375 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte 2376 ** past the end of the first SQL statement in zSql. These routines only 2377 ** compile the first statement in zSql, so *pzTail is left pointing to 2378 ** what remains uncompiled. 2379 ** 2380 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 2381 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 2382 ** to NULL. ^If the input text contains no SQL (if the input is an empty 2383 ** string or a comment) then *ppStmt is set to NULL. 2384 ** The calling procedure is responsible for deleting the compiled 2385 ** SQL statement using [sqlite3_finalize()] after it has finished with it. 2386 ** ppStmt may not be NULL. 2387 ** 2388 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 2389 ** otherwise an [error code] is returned. 2390 ** 2391 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2392 ** recommended for all new programs. The two older interfaces are retained 2393 ** for backwards compatibility, but their use is discouraged. 2394 ** ^In the "v2" interfaces, the prepared statement 2395 ** that is returned (the [sqlite3_stmt] object) contains a copy of the 2396 ** original SQL text. This causes the [sqlite3_step()] interface to 2397 ** behave differently in three ways: 2398 ** 2399 ** <ol> 2400 ** <li> 2401 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2402 ** always used to do, [sqlite3_step()] will automatically recompile the SQL 2403 ** statement and try to run it again. ^If the schema has changed in 2404 ** a way that makes the statement no longer valid, [sqlite3_step()] will still 2405 ** return [SQLITE_SCHEMA]. But unlike the legacy behavior, [SQLITE_SCHEMA] is 2406 ** now a fatal error. Calling [sqlite3_prepare_v2()] again will not make the 2407 ** error go away. Note: use [sqlite3_errmsg()] to find the text 2408 ** of the parsing error that results in an [SQLITE_SCHEMA] return. 2409 ** </li> 2410 ** 2411 ** <li> 2412 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed 2413 ** [error codes] or [extended error codes]. ^The legacy behavior was that 2414 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2415 ** and the application would have to make a second call to [sqlite3_reset()] 2416 ** in order to find the underlying cause of the problem. With the "v2" prepare 2417 ** interfaces, the underlying reason for the error is returned immediately. 2418 ** </li> 2419 ** 2420 ** <li> 2421 ** ^If the value of a [parameter | host parameter] in the WHERE clause might 2422 ** change the query plan for a statement, then the statement may be 2423 ** automatically recompiled (as if there had been a schema change) on the first 2424 ** [sqlite3_step()] call following any change to the 2425 ** [sqlite3_bind_text | bindings] of the [parameter]. 2426 ** </li> 2427 ** </ol> 2428 */ 2429 SQLITE_API int sqlite3_prepare( 2430 sqlite3 *db, /* Database handle */ 2431 const char *zSql, /* SQL statement, UTF-8 encoded */ 2432 int nByte, /* Maximum length of zSql in bytes. */ 2433 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2434 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2435 ); 2436 SQLITE_API int sqlite3_prepare_v2( 2437 sqlite3 *db, /* Database handle */ 2438 const char *zSql, /* SQL statement, UTF-8 encoded */ 2439 int nByte, /* Maximum length of zSql in bytes. */ 2440 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2441 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2442 ); 2443 SQLITE_API int sqlite3_prepare16( 2444 sqlite3 *db, /* Database handle */ 2445 const void *zSql, /* SQL statement, UTF-16 encoded */ 2446 int nByte, /* Maximum length of zSql in bytes. */ 2447 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2448 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2449 ); 2450 SQLITE_API int sqlite3_prepare16_v2( 2451 sqlite3 *db, /* Database handle */ 2452 const void *zSql, /* SQL statement, UTF-16 encoded */ 2453 int nByte, /* Maximum length of zSql in bytes. */ 2454 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2455 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2456 ); 2457 2458 /* 2459 ** CAPI3REF: Retrieving Statement SQL 2460 ** 2461 ** ^This interface can be used to retrieve a saved copy of the original 2462 ** SQL text used to create a [prepared statement] if that statement was 2463 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2464 */ 2465 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt); 2466 2467 /* 2468 ** CAPI3REF: Dynamically Typed Value Object 2469 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 2470 ** 2471 ** SQLite uses the sqlite3_value object to represent all values 2472 ** that can be stored in a database table. SQLite uses dynamic typing 2473 ** for the values it stores. ^Values stored in sqlite3_value objects 2474 ** can be integers, floating point values, strings, BLOBs, or NULL. 2475 ** 2476 ** An sqlite3_value object may be either "protected" or "unprotected". 2477 ** Some interfaces require a protected sqlite3_value. Other interfaces 2478 ** will accept either a protected or an unprotected sqlite3_value. 2479 ** Every interface that accepts sqlite3_value arguments specifies 2480 ** whether or not it requires a protected sqlite3_value. 2481 ** 2482 ** The terms "protected" and "unprotected" refer to whether or not 2483 ** a mutex is held. A internal mutex is held for a protected 2484 ** sqlite3_value object but no mutex is held for an unprotected 2485 ** sqlite3_value object. If SQLite is compiled to be single-threaded 2486 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 2487 ** or if SQLite is run in one of reduced mutex modes 2488 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 2489 ** then there is no distinction between protected and unprotected 2490 ** sqlite3_value objects and they can be used interchangeably. However, 2491 ** for maximum code portability it is recommended that applications 2492 ** still make the distinction between between protected and unprotected 2493 ** sqlite3_value objects even when not strictly required. 2494 ** 2495 ** ^The sqlite3_value objects that are passed as parameters into the 2496 ** implementation of [application-defined SQL functions] are protected. 2497 ** ^The sqlite3_value object returned by 2498 ** [sqlite3_column_value()] is unprotected. 2499 ** Unprotected sqlite3_value objects may only be used with 2500 ** [sqlite3_result_value()] and [sqlite3_bind_value()]. 2501 ** The [sqlite3_value_blob | sqlite3_value_type()] family of 2502 ** interfaces require protected sqlite3_value objects. 2503 */ 2504 typedef struct Mem sqlite3_value; 2505 2506 /* 2507 ** CAPI3REF: SQL Function Context Object 2508 ** 2509 ** The context in which an SQL function executes is stored in an 2510 ** sqlite3_context object. ^A pointer to an sqlite3_context object 2511 ** is always first parameter to [application-defined SQL functions]. 2512 ** The application-defined SQL function implementation will pass this 2513 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 2514 ** [sqlite3_aggregate_context()], [sqlite3_user_data()], 2515 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 2516 ** and/or [sqlite3_set_auxdata()]. 2517 */ 2518 typedef struct sqlite3_context sqlite3_context; 2519 2520 /* 2521 ** CAPI3REF: Binding Values To Prepared Statements 2522 ** KEYWORDS: {host parameter} {host parameters} {host parameter name} 2523 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 2524 ** 2525 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 2526 ** literals may be replaced by a [parameter] that matches one of following 2527 ** templates: 2528 ** 2529 ** <ul> 2530 ** <li> ? 2531 ** <li> ?NNN 2532 ** <li> :VVV 2533 ** <li> @VVV 2534 ** <li> $VVV 2535 ** </ul> 2536 ** 2537 ** In the templates above, NNN represents an integer literal, 2538 ** and VVV represents an alphanumeric identifer.)^ ^The values of these 2539 ** parameters (also called "host parameter names" or "SQL parameters") 2540 ** can be set using the sqlite3_bind_*() routines defined here. 2541 ** 2542 ** ^The first argument to the sqlite3_bind_*() routines is always 2543 ** a pointer to the [sqlite3_stmt] object returned from 2544 ** [sqlite3_prepare_v2()] or its variants. 2545 ** 2546 ** ^The second argument is the index of the SQL parameter to be set. 2547 ** ^The leftmost SQL parameter has an index of 1. ^When the same named 2548 ** SQL parameter is used more than once, second and subsequent 2549 ** occurrences have the same index as the first occurrence. 2550 ** ^The index for named parameters can be looked up using the 2551 ** [sqlite3_bind_parameter_index()] API if desired. ^The index 2552 ** for "?NNN" parameters is the value of NNN. 2553 ** ^The NNN value must be between 1 and the [sqlite3_limit()] 2554 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 2555 ** 2556 ** ^The third argument is the value to bind to the parameter. 2557 ** 2558 ** ^(In those routines that have a fourth argument, its value is the 2559 ** number of bytes in the parameter. To be clear: the value is the 2560 ** number of <u>bytes</u> in the value, not the number of characters.)^ 2561 ** ^If the fourth parameter is negative, the length of the string is 2562 ** the number of bytes up to the first zero terminator. 2563 ** 2564 ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 2565 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 2566 ** string after SQLite has finished with it. ^If the fifth argument is 2567 ** the special value [SQLITE_STATIC], then SQLite assumes that the 2568 ** information is in static, unmanaged space and does not need to be freed. 2569 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 2570 ** SQLite makes its own private copy of the data immediately, before 2571 ** the sqlite3_bind_*() routine returns. 2572 ** 2573 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 2574 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 2575 ** (just an integer to hold its size) while it is being processed. 2576 ** Zeroblobs are intended to serve as placeholders for BLOBs whose 2577 ** content is later written using 2578 ** [sqlite3_blob_open | incremental BLOB I/O] routines. 2579 ** ^A negative value for the zeroblob results in a zero-length BLOB. 2580 ** 2581 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 2582 ** for the [prepared statement] or with a prepared statement for which 2583 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 2584 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 2585 ** routine is passed a [prepared statement] that has been finalized, the 2586 ** result is undefined and probably harmful. 2587 ** 2588 ** ^Bindings are not cleared by the [sqlite3_reset()] routine. 2589 ** ^Unbound parameters are interpreted as NULL. 2590 ** 2591 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 2592 ** [error code] if anything goes wrong. 2593 ** ^[SQLITE_RANGE] is returned if the parameter 2594 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 2595 ** 2596 ** See also: [sqlite3_bind_parameter_count()], 2597 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 2598 */ 2599 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 2600 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double); 2601 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int); 2602 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 2603 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int); 2604 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 2605 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 2606 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 2607 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 2608 2609 /* 2610 ** CAPI3REF: Number Of SQL Parameters 2611 ** 2612 ** ^This routine can be used to find the number of [SQL parameters] 2613 ** in a [prepared statement]. SQL parameters are tokens of the 2614 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 2615 ** placeholders for values that are [sqlite3_bind_blob | bound] 2616 ** to the parameters at a later time. 2617 ** 2618 ** ^(This routine actually returns the index of the largest (rightmost) 2619 ** parameter. For all forms except ?NNN, this will correspond to the 2620 ** number of unique parameters. If parameters of the ?NNN form are used, 2621 ** there may be gaps in the list.)^ 2622 ** 2623 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 2624 ** [sqlite3_bind_parameter_name()], and 2625 ** [sqlite3_bind_parameter_index()]. 2626 */ 2627 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*); 2628 2629 /* 2630 ** CAPI3REF: Name Of A Host Parameter 2631 ** 2632 ** ^The sqlite3_bind_parameter_name(P,N) interface returns 2633 ** the name of the N-th [SQL parameter] in the [prepared statement] P. 2634 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 2635 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 2636 ** respectively. 2637 ** In other words, the initial ":" or "$" or "@" or "?" 2638 ** is included as part of the name.)^ 2639 ** ^Parameters of the form "?" without a following integer have no name 2640 ** and are referred to as "nameless" or "anonymous parameters". 2641 ** 2642 ** ^The first host parameter has an index of 1, not 0. 2643 ** 2644 ** ^If the value N is out of range or if the N-th parameter is 2645 ** nameless, then NULL is returned. ^The returned string is 2646 ** always in UTF-8 encoding even if the named parameter was 2647 ** originally specified as UTF-16 in [sqlite3_prepare16()] or 2648 ** [sqlite3_prepare16_v2()]. 2649 ** 2650 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 2651 ** [sqlite3_bind_parameter_count()], and 2652 ** [sqlite3_bind_parameter_index()]. 2653 */ 2654 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 2655 2656 /* 2657 ** CAPI3REF: Index Of A Parameter With A Given Name 2658 ** 2659 ** ^Return the index of an SQL parameter given its name. ^The 2660 ** index value returned is suitable for use as the second 2661 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 2662 ** is returned if no matching parameter is found. ^The parameter 2663 ** name must be given in UTF-8 even if the original statement 2664 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 2665 ** 2666 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 2667 ** [sqlite3_bind_parameter_count()], and 2668 ** [sqlite3_bind_parameter_index()]. 2669 */ 2670 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 2671 2672 /* 2673 ** CAPI3REF: Reset All Bindings On A Prepared Statement 2674 ** 2675 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 2676 ** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 2677 ** ^Use this routine to reset all host parameters to NULL. 2678 */ 2679 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*); 2680 2681 /* 2682 ** CAPI3REF: Number Of Columns In A Result Set 2683 ** 2684 ** ^Return the number of columns in the result set returned by the 2685 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 2686 ** statement that does not return data (for example an [UPDATE]). 2687 */ 2688 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt); 2689 2690 /* 2691 ** CAPI3REF: Column Names In A Result Set 2692 ** 2693 ** ^These routines return the name assigned to a particular column 2694 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 2695 ** interface returns a pointer to a zero-terminated UTF-8 string 2696 ** and sqlite3_column_name16() returns a pointer to a zero-terminated 2697 ** UTF-16 string. ^The first parameter is the [prepared statement] 2698 ** that implements the [SELECT] statement. ^The second parameter is the 2699 ** column number. ^The leftmost column is number 0. 2700 ** 2701 ** ^The returned string pointer is valid until either the [prepared statement] 2702 ** is destroyed by [sqlite3_finalize()] or until the next call to 2703 ** sqlite3_column_name() or sqlite3_column_name16() on the same column. 2704 ** 2705 ** ^If sqlite3_malloc() fails during the processing of either routine 2706 ** (for example during a conversion from UTF-8 to UTF-16) then a 2707 ** NULL pointer is returned. 2708 ** 2709 ** ^The name of a result column is the value of the "AS" clause for 2710 ** that column, if there is an AS clause. If there is no AS clause 2711 ** then the name of the column is unspecified and may change from 2712 ** one release of SQLite to the next. 2713 */ 2714 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N); 2715 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N); 2716 2717 /* 2718 ** CAPI3REF: Source Of Data In A Query Result 2719 ** 2720 ** ^These routines provide a means to determine the database, table, and 2721 ** table column that is the origin of a particular result column in 2722 ** [SELECT] statement. 2723 ** ^The name of the database or table or column can be returned as 2724 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return 2725 ** the database name, the _table_ routines return the table name, and 2726 ** the origin_ routines return the column name. 2727 ** ^The returned string is valid until the [prepared statement] is destroyed 2728 ** using [sqlite3_finalize()] or until the same information is requested 2729 ** again in a different encoding. 2730 ** 2731 ** ^The names returned are the original un-aliased names of the 2732 ** database, table, and column. 2733 ** 2734 ** ^The first argument to these interfaces is a [prepared statement]. 2735 ** ^These functions return information about the Nth result column returned by 2736 ** the statement, where N is the second function argument. 2737 ** ^The left-most column is column 0 for these routines. 2738 ** 2739 ** ^If the Nth column returned by the statement is an expression or 2740 ** subquery and is not a column value, then all of these functions return 2741 ** NULL. ^These routine might also return NULL if a memory allocation error 2742 ** occurs. ^Otherwise, they return the name of the attached database, table, 2743 ** or column that query result column was extracted from. 2744 ** 2745 ** ^As with all other SQLite APIs, those whose names end with "16" return 2746 ** UTF-16 encoded strings and the other functions return UTF-8. 2747 ** 2748 ** ^These APIs are only available if the library was compiled with the 2749 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 2750 ** 2751 ** If two or more threads call one or more of these routines against the same 2752 ** prepared statement and column at the same time then the results are 2753 ** undefined. 2754 ** 2755 ** If two or more threads call one or more 2756 ** [sqlite3_column_database_name | column metadata interfaces] 2757 ** for the same [prepared statement] and result column 2758 ** at the same time then the results are undefined. 2759 */ 2760 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int); 2761 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 2762 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int); 2763 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 2764 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 2765 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 2766 2767 /* 2768 ** CAPI3REF: Declared Datatype Of A Query Result 2769 ** 2770 ** ^(The first parameter is a [prepared statement]. 2771 ** If this statement is a [SELECT] statement and the Nth column of the 2772 ** returned result set of that [SELECT] is a table column (not an 2773 ** expression or subquery) then the declared type of the table 2774 ** column is returned.)^ ^If the Nth column of the result set is an 2775 ** expression or subquery, then a NULL pointer is returned. 2776 ** ^The returned string is always UTF-8 encoded. 2777 ** 2778 ** ^(For example, given the database schema: 2779 ** 2780 ** CREATE TABLE t1(c1 VARIANT); 2781 ** 2782 ** and the following statement to be compiled: 2783 ** 2784 ** SELECT c1 + 1, c1 FROM t1; 2785 ** 2786 ** this routine would return the string "VARIANT" for the second result 2787 ** column (i==1), and a NULL pointer for the first result column (i==0).)^ 2788 ** 2789 ** ^SQLite uses dynamic run-time typing. ^So just because a column 2790 ** is declared to contain a particular type does not mean that the 2791 ** data stored in that column is of the declared type. SQLite is 2792 ** strongly typed, but the typing is dynamic not static. ^Type 2793 ** is associated with individual values, not with the containers 2794 ** used to hold those values. 2795 */ 2796 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int); 2797 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 2798 2799 /* 2800 ** CAPI3REF: Evaluate An SQL Statement 2801 ** 2802 ** After a [prepared statement] has been prepared using either 2803 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 2804 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 2805 ** must be called one or more times to evaluate the statement. 2806 ** 2807 ** The details of the behavior of the sqlite3_step() interface depend 2808 ** on whether the statement was prepared using the newer "v2" interface 2809 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 2810 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 2811 ** new "v2" interface is recommended for new applications but the legacy 2812 ** interface will continue to be supported. 2813 ** 2814 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 2815 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 2816 ** ^With the "v2" interface, any of the other [result codes] or 2817 ** [extended result codes] might be returned as well. 2818 ** 2819 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 2820 ** database locks it needs to do its job. ^If the statement is a [COMMIT] 2821 ** or occurs outside of an explicit transaction, then you can retry the 2822 ** statement. If the statement is not a [COMMIT] and occurs within a 2823 ** explicit transaction then you should rollback the transaction before 2824 ** continuing. 2825 ** 2826 ** ^[SQLITE_DONE] means that the statement has finished executing 2827 ** successfully. sqlite3_step() should not be called again on this virtual 2828 ** machine without first calling [sqlite3_reset()] to reset the virtual 2829 ** machine back to its initial state. 2830 ** 2831 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 2832 ** is returned each time a new row of data is ready for processing by the 2833 ** caller. The values may be accessed using the [column access functions]. 2834 ** sqlite3_step() is called again to retrieve the next row of data. 2835 ** 2836 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 2837 ** violation) has occurred. sqlite3_step() should not be called again on 2838 ** the VM. More information may be found by calling [sqlite3_errmsg()]. 2839 ** ^With the legacy interface, a more specific error code (for example, 2840 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 2841 ** can be obtained by calling [sqlite3_reset()] on the 2842 ** [prepared statement]. ^In the "v2" interface, 2843 ** the more specific error code is returned directly by sqlite3_step(). 2844 ** 2845 ** [SQLITE_MISUSE] means that the this routine was called inappropriately. 2846 ** Perhaps it was called on a [prepared statement] that has 2847 ** already been [sqlite3_finalize | finalized] or on one that had 2848 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 2849 ** be the case that the same database connection is being used by two or 2850 ** more threads at the same moment in time. 2851 ** 2852 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 2853 ** API always returns a generic error code, [SQLITE_ERROR], following any 2854 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 2855 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 2856 ** specific [error codes] that better describes the error. 2857 ** We admit that this is a goofy design. The problem has been fixed 2858 ** with the "v2" interface. If you prepare all of your SQL statements 2859 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 2860 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 2861 ** then the more specific [error codes] are returned directly 2862 ** by sqlite3_step(). The use of the "v2" interface is recommended. 2863 */ 2864 SQLITE_API int sqlite3_step(sqlite3_stmt*); 2865 2866 /* 2867 ** CAPI3REF: Number of columns in a result set 2868 ** 2869 ** ^The sqlite3_data_count(P) the number of columns in the 2870 ** of the result set of [prepared statement] P. 2871 */ 2872 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt); 2873 2874 /* 2875 ** CAPI3REF: Fundamental Datatypes 2876 ** KEYWORDS: SQLITE_TEXT 2877 ** 2878 ** ^(Every value in SQLite has one of five fundamental datatypes: 2879 ** 2880 ** <ul> 2881 ** <li> 64-bit signed integer 2882 ** <li> 64-bit IEEE floating point number 2883 ** <li> string 2884 ** <li> BLOB 2885 ** <li> NULL 2886 ** </ul>)^ 2887 ** 2888 ** These constants are codes for each of those types. 2889 ** 2890 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2 2891 ** for a completely different meaning. Software that links against both 2892 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 2893 ** SQLITE_TEXT. 2894 */ 2895 #define SQLITE_INTEGER 1 2896 #define SQLITE_FLOAT 2 2897 #define SQLITE_BLOB 4 2898 #define SQLITE_NULL 5 2899 #ifdef SQLITE_TEXT 2900 # undef SQLITE_TEXT 2901 #else 2902 # define SQLITE_TEXT 3 2903 #endif 2904 #define SQLITE3_TEXT 3 2905 2906 /* 2907 ** CAPI3REF: Result Values From A Query 2908 ** KEYWORDS: {column access functions} 2909 ** 2910 ** These routines form the "result set" interface. 2911 ** 2912 ** ^These routines return information about a single column of the current 2913 ** result row of a query. ^In every case the first argument is a pointer 2914 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 2915 ** that was returned from [sqlite3_prepare_v2()] or one of its variants) 2916 ** and the second argument is the index of the column for which information 2917 ** should be returned. ^The leftmost column of the result set has the index 0. 2918 ** ^The number of columns in the result can be determined using 2919 ** [sqlite3_column_count()]. 2920 ** 2921 ** If the SQL statement does not currently point to a valid row, or if the 2922 ** column index is out of range, the result is undefined. 2923 ** These routines may only be called when the most recent call to 2924 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither 2925 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 2926 ** If any of these routines are called after [sqlite3_reset()] or 2927 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned 2928 ** something other than [SQLITE_ROW], the results are undefined. 2929 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 2930 ** are called from a different thread while any of these routines 2931 ** are pending, then the results are undefined. 2932 ** 2933 ** ^The sqlite3_column_type() routine returns the 2934 ** [SQLITE_INTEGER | datatype code] for the initial data type 2935 ** of the result column. ^The returned value is one of [SQLITE_INTEGER], 2936 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 2937 ** returned by sqlite3_column_type() is only meaningful if no type 2938 ** conversions have occurred as described below. After a type conversion, 2939 ** the value returned by sqlite3_column_type() is undefined. Future 2940 ** versions of SQLite may change the behavior of sqlite3_column_type() 2941 ** following a type conversion. 2942 ** 2943 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 2944 ** routine returns the number of bytes in that BLOB or string. 2945 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 2946 ** the string to UTF-8 and then returns the number of bytes. 2947 ** ^If the result is a numeric value then sqlite3_column_bytes() uses 2948 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 2949 ** the number of bytes in that string. 2950 ** ^The value returned does not include the zero terminator at the end 2951 ** of the string. ^For clarity: the value returned is the number of 2952 ** bytes in the string, not the number of characters. 2953 ** 2954 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 2955 ** even empty strings, are always zero terminated. ^The return 2956 ** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary 2957 ** pointer, possibly even a NULL pointer. 2958 ** 2959 ** ^The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes() 2960 ** but leaves the result in UTF-16 in native byte order instead of UTF-8. 2961 ** ^The zero terminator is not included in this count. 2962 ** 2963 ** ^The object returned by [sqlite3_column_value()] is an 2964 ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 2965 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 2966 ** If the [unprotected sqlite3_value] object returned by 2967 ** [sqlite3_column_value()] is used in any other way, including calls 2968 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 2969 ** or [sqlite3_value_bytes()], then the behavior is undefined. 2970 ** 2971 ** These routines attempt to convert the value where appropriate. ^For 2972 ** example, if the internal representation is FLOAT and a text result 2973 ** is requested, [sqlite3_snprintf()] is used internally to perform the 2974 ** conversion automatically. ^(The following table details the conversions 2975 ** that are applied: 2976 ** 2977 ** <blockquote> 2978 ** <table border="1"> 2979 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 2980 ** 2981 ** <tr><td> NULL <td> INTEGER <td> Result is 0 2982 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0 2983 ** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 2984 ** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 2985 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 2986 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 2987 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 2988 ** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 2989 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 2990 ** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 2991 ** <tr><td> TEXT <td> INTEGER <td> Use atoi() 2992 ** <tr><td> TEXT <td> FLOAT <td> Use atof() 2993 ** <tr><td> TEXT <td> BLOB <td> No change 2994 ** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 2995 ** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 2996 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 2997 ** </table> 2998 ** </blockquote>)^ 2999 ** 3000 ** The table above makes reference to standard C library functions atoi() 3001 ** and atof(). SQLite does not really use these functions. It has its 3002 ** own equivalent internal routines. The atoi() and atof() names are 3003 ** used in the table for brevity and because they are familiar to most 3004 ** C programmers. 3005 ** 3006 ** ^Note that when type conversions occur, pointers returned by prior 3007 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3008 ** sqlite3_column_text16() may be invalidated. 3009 ** ^(Type conversions and pointer invalidations might occur 3010 ** in the following cases: 3011 ** 3012 ** <ul> 3013 ** <li> The initial content is a BLOB and sqlite3_column_text() or 3014 ** sqlite3_column_text16() is called. A zero-terminator might 3015 ** need to be added to the string.</li> 3016 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3017 ** sqlite3_column_text16() is called. The content must be converted 3018 ** to UTF-16.</li> 3019 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3020 ** sqlite3_column_text() is called. The content must be converted 3021 ** to UTF-8.</li> 3022 ** </ul>)^ 3023 ** 3024 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3025 ** not invalidate a prior pointer, though of course the content of the buffer 3026 ** that the prior pointer points to will have been modified. Other kinds 3027 ** of conversion are done in place when it is possible, but sometimes they 3028 ** are not possible and in those cases prior pointers are invalidated. 3029 ** 3030 ** ^(The safest and easiest to remember policy is to invoke these routines 3031 ** in one of the following ways: 3032 ** 3033 ** <ul> 3034 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3035 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3036 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3037 ** </ul>)^ 3038 ** 3039 ** In other words, you should call sqlite3_column_text(), 3040 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3041 ** into the desired format, then invoke sqlite3_column_bytes() or 3042 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3043 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3044 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3045 ** with calls to sqlite3_column_bytes(). 3046 ** 3047 ** ^The pointers returned are valid until a type conversion occurs as 3048 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3049 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3050 ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3051 ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3052 ** [sqlite3_free()]. 3053 ** 3054 ** ^(If a memory allocation error occurs during the evaluation of any 3055 ** of these routines, a default value is returned. The default value 3056 ** is either the integer 0, the floating point number 0.0, or a NULL 3057 ** pointer. Subsequent calls to [sqlite3_errcode()] will return 3058 ** [SQLITE_NOMEM].)^ 3059 */ 3060 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3061 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3062 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3063 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol); 3064 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol); 3065 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3066 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3067 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3068 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol); 3069 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3070 3071 /* 3072 ** CAPI3REF: Destroy A Prepared Statement Object 3073 ** 3074 ** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3075 ** ^If the statement was executed successfully or not executed at all, then 3076 ** SQLITE_OK is returned. ^If execution of the statement failed then an 3077 ** [error code] or [extended error code] is returned. 3078 ** 3079 ** ^This routine can be called at any point during the execution of the 3080 ** [prepared statement]. ^If the virtual machine has not 3081 ** completed execution when this routine is called, that is like 3082 ** encountering an error or an [sqlite3_interrupt | interrupt]. 3083 ** ^Incomplete updates may be rolled back and transactions canceled, 3084 ** depending on the circumstances, and the 3085 ** [error code] returned will be [SQLITE_ABORT]. 3086 */ 3087 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt); 3088 3089 /* 3090 ** CAPI3REF: Reset A Prepared Statement Object 3091 ** 3092 ** The sqlite3_reset() function is called to reset a [prepared statement] 3093 ** object back to its initial state, ready to be re-executed. 3094 ** ^Any SQL statement variables that had values bound to them using 3095 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3096 ** Use [sqlite3_clear_bindings()] to reset the bindings. 3097 ** 3098 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3099 ** back to the beginning of its program. 3100 ** 3101 ** ^If the most recent call to [sqlite3_step(S)] for the 3102 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3103 ** or if [sqlite3_step(S)] has never before been called on S, 3104 ** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3105 ** 3106 ** ^If the most recent call to [sqlite3_step(S)] for the 3107 ** [prepared statement] S indicated an error, then 3108 ** [sqlite3_reset(S)] returns an appropriate [error code]. 3109 ** 3110 ** ^The [sqlite3_reset(S)] interface does not change the values 3111 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3112 */ 3113 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt); 3114 3115 /* 3116 ** CAPI3REF: Create Or Redefine SQL Functions 3117 ** KEYWORDS: {function creation routines} 3118 ** KEYWORDS: {application-defined SQL function} 3119 ** KEYWORDS: {application-defined SQL functions} 3120 ** 3121 ** ^These two functions (collectively known as "function creation routines") 3122 ** are used to add SQL functions or aggregates or to redefine the behavior 3123 ** of existing SQL functions or aggregates. The only difference between the 3124 ** two is that the second parameter, the name of the (scalar) function or 3125 ** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16 3126 ** for sqlite3_create_function16(). 3127 ** 3128 ** ^The first parameter is the [database connection] to which the SQL 3129 ** function is to be added. ^If an application uses more than one database 3130 ** connection then application-defined SQL functions must be added 3131 ** to each database connection separately. 3132 ** 3133 ** The second parameter is the name of the SQL function to be created or 3134 ** redefined. ^The length of the name is limited to 255 bytes, exclusive of 3135 ** the zero-terminator. Note that the name length limit is in bytes, not 3136 ** characters. ^Any attempt to create a function with a longer name 3137 ** will result in [SQLITE_ERROR] being returned. 3138 ** 3139 ** ^The third parameter (nArg) 3140 ** is the number of arguments that the SQL function or 3141 ** aggregate takes. ^If this parameter is -1, then the SQL function or 3142 ** aggregate may take any number of arguments between 0 and the limit 3143 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3144 ** parameter is less than -1 or greater than 127 then the behavior is 3145 ** undefined. 3146 ** 3147 ** The fourth parameter, eTextRep, specifies what 3148 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3149 ** its parameters. Any SQL function implementation should be able to work 3150 ** work with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3151 ** more efficient with one encoding than another. ^An application may 3152 ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3153 ** times with the same function but with different values of eTextRep. 3154 ** ^When multiple implementations of the same function are available, SQLite 3155 ** will pick the one that involves the least amount of data conversion. 3156 ** If there is only a single implementation which does not care what text 3157 ** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3158 ** 3159 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3160 ** function can gain access to this pointer using [sqlite3_user_data()].)^ 3161 ** 3162 ** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are 3163 ** pointers to C-language functions that implement the SQL function or 3164 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3165 ** callback only; NULL pointers should be passed as the xStep and xFinal 3166 ** parameters. ^An aggregate SQL function requires an implementation of xStep 3167 ** and xFinal and NULL should be passed for xFunc. ^To delete an existing 3168 ** SQL function or aggregate, pass NULL for all three function callbacks. 3169 ** 3170 ** ^It is permitted to register multiple implementations of the same 3171 ** functions with the same name but with either differing numbers of 3172 ** arguments or differing preferred text encodings. ^SQLite will use 3173 ** the implementation that most closely matches the way in which the 3174 ** SQL function is used. ^A function implementation with a non-negative 3175 ** nArg parameter is a better match than a function implementation with 3176 ** a negative nArg. ^A function where the preferred text encoding 3177 ** matches the database encoding is a better 3178 ** match than a function where the encoding is different. 3179 ** ^A function where the encoding difference is between UTF16le and UTF16be 3180 ** is a closer match than a function where the encoding difference is 3181 ** between UTF8 and UTF16. 3182 ** 3183 ** ^Built-in functions may be overloaded by new application-defined functions. 3184 ** ^The first application-defined function with a given name overrides all 3185 ** built-in functions in the same [database connection] with the same name. 3186 ** ^Subsequent application-defined functions of the same name only override 3187 ** prior application-defined functions that are an exact match for the 3188 ** number of parameters and preferred encoding. 3189 ** 3190 ** ^An application-defined function is permitted to call other 3191 ** SQLite interfaces. However, such calls must not 3192 ** close the database connection nor finalize or reset the prepared 3193 ** statement in which the function is running. 3194 */ 3195 SQLITE_API int sqlite3_create_function( 3196 sqlite3 *db, 3197 const char *zFunctionName, 3198 int nArg, 3199 int eTextRep, 3200 void *pApp, 3201 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3202 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3203 void (*xFinal)(sqlite3_context*) 3204 ); 3205 SQLITE_API int sqlite3_create_function16( 3206 sqlite3 *db, 3207 const void *zFunctionName, 3208 int nArg, 3209 int eTextRep, 3210 void *pApp, 3211 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3212 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3213 void (*xFinal)(sqlite3_context*) 3214 ); 3215 3216 /* 3217 ** CAPI3REF: Text Encodings 3218 ** 3219 ** These constant define integer codes that represent the various 3220 ** text encodings supported by SQLite. 3221 */ 3222 #define SQLITE_UTF8 1 3223 #define SQLITE_UTF16LE 2 3224 #define SQLITE_UTF16BE 3 3225 #define SQLITE_UTF16 4 /* Use native byte order */ 3226 #define SQLITE_ANY 5 /* sqlite3_create_function only */ 3227 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3228 3229 /* 3230 ** CAPI3REF: Deprecated Functions 3231 ** DEPRECATED 3232 ** 3233 ** These functions are [deprecated]. In order to maintain 3234 ** backwards compatibility with older code, these functions continue 3235 ** to be supported. However, new applications should avoid 3236 ** the use of these functions. To help encourage people to avoid 3237 ** using these functions, we are not going to tell you what they do. 3238 */ 3239 #ifndef SQLITE_OMIT_DEPRECATED 3240 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3241 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3242 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3243 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void); 3244 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3245 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3246 #endif 3247 3248 /* 3249 ** CAPI3REF: Obtaining SQL Function Parameter Values 3250 ** 3251 ** The C-language implementation of SQL functions and aggregates uses 3252 ** this set of interface routines to access the parameter values on 3253 ** the function or aggregate. 3254 ** 3255 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3256 ** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3257 ** define callbacks that implement the SQL functions and aggregates. 3258 ** The 4th parameter to these callbacks is an array of pointers to 3259 ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3260 ** each parameter to the SQL function. These routines are used to 3261 ** extract values from the [sqlite3_value] objects. 3262 ** 3263 ** These routines work only with [protected sqlite3_value] objects. 3264 ** Any attempt to use these routines on an [unprotected sqlite3_value] 3265 ** object results in undefined behavior. 3266 ** 3267 ** ^These routines work just like the corresponding [column access functions] 3268 ** except that these routines take a single [protected sqlite3_value] object 3269 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3270 ** 3271 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string 3272 ** in the native byte-order of the host machine. ^The 3273 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3274 ** extract UTF-16 strings as big-endian and little-endian respectively. 3275 ** 3276 ** ^(The sqlite3_value_numeric_type() interface attempts to apply 3277 ** numeric affinity to the value. This means that an attempt is 3278 ** made to convert the value to an integer or floating point. If 3279 ** such a conversion is possible without loss of information (in other 3280 ** words, if the value is a string that looks like a number) 3281 ** then the conversion is performed. Otherwise no conversion occurs. 3282 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 3283 ** 3284 ** Please pay particular attention to the fact that the pointer returned 3285 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3286 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3287 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3288 ** or [sqlite3_value_text16()]. 3289 ** 3290 ** These routines must be called from the same thread as 3291 ** the SQL function that supplied the [sqlite3_value*] parameters. 3292 */ 3293 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*); 3294 SQLITE_API int sqlite3_value_bytes(sqlite3_value*); 3295 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*); 3296 SQLITE_API double sqlite3_value_double(sqlite3_value*); 3297 SQLITE_API int sqlite3_value_int(sqlite3_value*); 3298 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3299 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*); 3300 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*); 3301 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*); 3302 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*); 3303 SQLITE_API int sqlite3_value_type(sqlite3_value*); 3304 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*); 3305 3306 /* 3307 ** CAPI3REF: Obtain Aggregate Function Context 3308 ** 3309 ** Implementions of aggregate SQL functions use this 3310 ** routine to allocate memory for storing their state. 3311 ** 3312 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called 3313 ** for a particular aggregate function, SQLite 3314 ** allocates N of memory, zeroes out that memory, and returns a pointer 3315 ** to the new memory. ^On second and subsequent calls to 3316 ** sqlite3_aggregate_context() for the same aggregate function instance, 3317 ** the same buffer is returned. Sqlite3_aggregate_context() is normally 3318 ** called once for each invocation of the xStep callback and then one 3319 ** last time when the xFinal callback is invoked. ^(When no rows match 3320 ** an aggregate query, the xStep() callback of the aggregate function 3321 ** implementation is never called and xFinal() is called exactly once. 3322 ** In those cases, sqlite3_aggregate_context() might be called for the 3323 ** first time from within xFinal().)^ 3324 ** 3325 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is 3326 ** less than or equal to zero or if a memory allocate error occurs. 3327 ** 3328 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 3329 ** determined by the N parameter on first successful call. Changing the 3330 ** value of N in subsequent call to sqlite3_aggregate_context() within 3331 ** the same aggregate function instance will not resize the memory 3332 ** allocation.)^ 3333 ** 3334 ** ^SQLite automatically frees the memory allocated by 3335 ** sqlite3_aggregate_context() when the aggregate query concludes. 3336 ** 3337 ** The first parameter must be a copy of the 3338 ** [sqlite3_context | SQL function context] that is the first parameter 3339 ** to the xStep or xFinal callback routine that implements the aggregate 3340 ** function. 3341 ** 3342 ** This routine must be called from the same thread in which 3343 ** the aggregate SQL function is running. 3344 */ 3345 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 3346 3347 /* 3348 ** CAPI3REF: User Data For Functions 3349 ** 3350 ** ^The sqlite3_user_data() interface returns a copy of 3351 ** the pointer that was the pUserData parameter (the 5th parameter) 3352 ** of the [sqlite3_create_function()] 3353 ** and [sqlite3_create_function16()] routines that originally 3354 ** registered the application defined function. 3355 ** 3356 ** This routine must be called from the same thread in which 3357 ** the application-defined function is running. 3358 */ 3359 SQLITE_API void *sqlite3_user_data(sqlite3_context*); 3360 3361 /* 3362 ** CAPI3REF: Database Connection For Functions 3363 ** 3364 ** ^The sqlite3_context_db_handle() interface returns a copy of 3365 ** the pointer to the [database connection] (the 1st parameter) 3366 ** of the [sqlite3_create_function()] 3367 ** and [sqlite3_create_function16()] routines that originally 3368 ** registered the application defined function. 3369 */ 3370 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 3371 3372 /* 3373 ** CAPI3REF: Function Auxiliary Data 3374 ** 3375 ** The following two functions may be used by scalar SQL functions to 3376 ** associate metadata with argument values. If the same value is passed to 3377 ** multiple invocations of the same SQL function during query execution, under 3378 ** some circumstances the associated metadata may be preserved. This may 3379 ** be used, for example, to add a regular-expression matching scalar 3380 ** function. The compiled version of the regular expression is stored as 3381 ** metadata associated with the SQL value passed as the regular expression 3382 ** pattern. The compiled regular expression can be reused on multiple 3383 ** invocations of the same function so that the original pattern string 3384 ** does not need to be recompiled on each invocation. 3385 ** 3386 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 3387 ** associated by the sqlite3_set_auxdata() function with the Nth argument 3388 ** value to the application-defined function. ^If no metadata has been ever 3389 ** been set for the Nth argument of the function, or if the corresponding 3390 ** function parameter has changed since the meta-data was set, 3391 ** then sqlite3_get_auxdata() returns a NULL pointer. 3392 ** 3393 ** ^The sqlite3_set_auxdata() interface saves the metadata 3394 ** pointed to by its 3rd parameter as the metadata for the N-th 3395 ** argument of the application-defined function. Subsequent 3396 ** calls to sqlite3_get_auxdata() might return this data, if it has 3397 ** not been destroyed. 3398 ** ^If it is not NULL, SQLite will invoke the destructor 3399 ** function given by the 4th parameter to sqlite3_set_auxdata() on 3400 ** the metadata when the corresponding function parameter changes 3401 ** or when the SQL statement completes, whichever comes first. 3402 ** 3403 ** SQLite is free to call the destructor and drop metadata on any 3404 ** parameter of any function at any time. ^The only guarantee is that 3405 ** the destructor will be called before the metadata is dropped. 3406 ** 3407 ** ^(In practice, metadata is preserved between function calls for 3408 ** expressions that are constant at compile time. This includes literal 3409 ** values and [parameters].)^ 3410 ** 3411 ** These routines must be called from the same thread in which 3412 ** the SQL function is running. 3413 */ 3414 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N); 3415 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 3416 3417 3418 /* 3419 ** CAPI3REF: Constants Defining Special Destructor Behavior 3420 ** 3421 ** These are special values for the destructor that is passed in as the 3422 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 3423 ** argument is SQLITE_STATIC, it means that the content pointer is constant 3424 ** and will never change. It does not need to be destroyed. ^The 3425 ** SQLITE_TRANSIENT value means that the content will likely change in 3426 ** the near future and that SQLite should make its own private copy of 3427 ** the content before returning. 3428 ** 3429 ** The typedef is necessary to work around problems in certain 3430 ** C++ compilers. See ticket #2191. 3431 */ 3432 typedef void (*sqlite3_destructor_type)(void*); 3433 #define SQLITE_STATIC ((sqlite3_destructor_type)0) 3434 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 3435 3436 /* 3437 ** CAPI3REF: Setting The Result Of An SQL Function 3438 ** 3439 ** These routines are used by the xFunc or xFinal callbacks that 3440 ** implement SQL functions and aggregates. See 3441 ** [sqlite3_create_function()] and [sqlite3_create_function16()] 3442 ** for additional information. 3443 ** 3444 ** These functions work very much like the [parameter binding] family of 3445 ** functions used to bind values to host parameters in prepared statements. 3446 ** Refer to the [SQL parameter] documentation for additional information. 3447 ** 3448 ** ^The sqlite3_result_blob() interface sets the result from 3449 ** an application-defined function to be the BLOB whose content is pointed 3450 ** to by the second parameter and which is N bytes long where N is the 3451 ** third parameter. 3452 ** 3453 ** ^The sqlite3_result_zeroblob() interfaces set the result of 3454 ** the application-defined function to be a BLOB containing all zero 3455 ** bytes and N bytes in size, where N is the value of the 2nd parameter. 3456 ** 3457 ** ^The sqlite3_result_double() interface sets the result from 3458 ** an application-defined function to be a floating point value specified 3459 ** by its 2nd argument. 3460 ** 3461 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions 3462 ** cause the implemented SQL function to throw an exception. 3463 ** ^SQLite uses the string pointed to by the 3464 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 3465 ** as the text of an error message. ^SQLite interprets the error 3466 ** message string from sqlite3_result_error() as UTF-8. ^SQLite 3467 ** interprets the string from sqlite3_result_error16() as UTF-16 in native 3468 ** byte order. ^If the third parameter to sqlite3_result_error() 3469 ** or sqlite3_result_error16() is negative then SQLite takes as the error 3470 ** message all text up through the first zero character. 3471 ** ^If the third parameter to sqlite3_result_error() or 3472 ** sqlite3_result_error16() is non-negative then SQLite takes that many 3473 ** bytes (not characters) from the 2nd parameter as the error message. 3474 ** ^The sqlite3_result_error() and sqlite3_result_error16() 3475 ** routines make a private copy of the error message text before 3476 ** they return. Hence, the calling function can deallocate or 3477 ** modify the text after they return without harm. 3478 ** ^The sqlite3_result_error_code() function changes the error code 3479 ** returned by SQLite as a result of an error in a function. ^By default, 3480 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 3481 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 3482 ** 3483 ** ^The sqlite3_result_toobig() interface causes SQLite to throw an error 3484 ** indicating that a string or BLOB is too long to represent. 3485 ** 3486 ** ^The sqlite3_result_nomem() interface causes SQLite to throw an error 3487 ** indicating that a memory allocation failed. 3488 ** 3489 ** ^The sqlite3_result_int() interface sets the return value 3490 ** of the application-defined function to be the 32-bit signed integer 3491 ** value given in the 2nd argument. 3492 ** ^The sqlite3_result_int64() interface sets the return value 3493 ** of the application-defined function to be the 64-bit signed integer 3494 ** value given in the 2nd argument. 3495 ** 3496 ** ^The sqlite3_result_null() interface sets the return value 3497 ** of the application-defined function to be NULL. 3498 ** 3499 ** ^The sqlite3_result_text(), sqlite3_result_text16(), 3500 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 3501 ** set the return value of the application-defined function to be 3502 ** a text string which is represented as UTF-8, UTF-16 native byte order, 3503 ** UTF-16 little endian, or UTF-16 big endian, respectively. 3504 ** ^SQLite takes the text result from the application from 3505 ** the 2nd parameter of the sqlite3_result_text* interfaces. 3506 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces 3507 ** is negative, then SQLite takes result text from the 2nd parameter 3508 ** through the first zero character. 3509 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces 3510 ** is non-negative, then as many bytes (not characters) of the text 3511 ** pointed to by the 2nd parameter are taken as the application-defined 3512 ** function result. 3513 ** ^If the 4th parameter to the sqlite3_result_text* interfaces 3514 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 3515 ** function as the destructor on the text or BLOB result when it has 3516 ** finished using that result. 3517 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 3518 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 3519 ** assumes that the text or BLOB result is in constant space and does not 3520 ** copy the content of the parameter nor call a destructor on the content 3521 ** when it has finished using that result. 3522 ** ^If the 4th parameter to the sqlite3_result_text* interfaces 3523 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 3524 ** then SQLite makes a copy of the result into space obtained from 3525 ** from [sqlite3_malloc()] before it returns. 3526 ** 3527 ** ^The sqlite3_result_value() interface sets the result of 3528 ** the application-defined function to be a copy the 3529 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 3530 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 3531 ** so that the [sqlite3_value] specified in the parameter may change or 3532 ** be deallocated after sqlite3_result_value() returns without harm. 3533 ** ^A [protected sqlite3_value] object may always be used where an 3534 ** [unprotected sqlite3_value] object is required, so either 3535 ** kind of [sqlite3_value] object can be used with this interface. 3536 ** 3537 ** If these routines are called from within the different thread 3538 ** than the one containing the application-defined function that received 3539 ** the [sqlite3_context] pointer, the results are undefined. 3540 */ 3541 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 3542 SQLITE_API void sqlite3_result_double(sqlite3_context*, double); 3543 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int); 3544 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int); 3545 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*); 3546 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*); 3547 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int); 3548 SQLITE_API void sqlite3_result_int(sqlite3_context*, int); 3549 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 3550 SQLITE_API void sqlite3_result_null(sqlite3_context*); 3551 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 3552 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 3553 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 3554 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 3555 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 3556 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n); 3557 3558 /* 3559 ** CAPI3REF: Define New Collating Sequences 3560 ** 3561 ** These functions are used to add new collation sequences to the 3562 ** [database connection] specified as the first argument. 3563 ** 3564 ** ^The name of the new collation sequence is specified as a UTF-8 string 3565 ** for sqlite3_create_collation() and sqlite3_create_collation_v2() 3566 ** and a UTF-16 string for sqlite3_create_collation16(). ^In all cases 3567 ** the name is passed as the second function argument. 3568 ** 3569 ** ^The third argument may be one of the constants [SQLITE_UTF8], 3570 ** [SQLITE_UTF16LE], or [SQLITE_UTF16BE], indicating that the user-supplied 3571 ** routine expects to be passed pointers to strings encoded using UTF-8, 3572 ** UTF-16 little-endian, or UTF-16 big-endian, respectively. ^The 3573 ** third argument might also be [SQLITE_UTF16] to indicate that the routine 3574 ** expects pointers to be UTF-16 strings in the native byte order, or the 3575 ** argument can be [SQLITE_UTF16_ALIGNED] if the 3576 ** the routine expects pointers to 16-bit word aligned strings 3577 ** of UTF-16 in the native byte order. 3578 ** 3579 ** A pointer to the user supplied routine must be passed as the fifth 3580 ** argument. ^If it is NULL, this is the same as deleting the collation 3581 ** sequence (so that SQLite cannot call it anymore). 3582 ** ^Each time the application supplied function is invoked, it is passed 3583 ** as its first parameter a copy of the void* passed as the fourth argument 3584 ** to sqlite3_create_collation() or sqlite3_create_collation16(). 3585 ** 3586 ** ^The remaining arguments to the application-supplied routine are two strings, 3587 ** each represented by a (length, data) pair and encoded in the encoding 3588 ** that was passed as the third argument when the collation sequence was 3589 ** registered. The application defined collation routine should 3590 ** return negative, zero or positive if the first string is less than, 3591 ** equal to, or greater than the second string. i.e. (STRING1 - STRING2). 3592 ** 3593 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 3594 ** except that it takes an extra argument which is a destructor for 3595 ** the collation. ^The destructor is called when the collation is 3596 ** destroyed and is passed a copy of the fourth parameter void* pointer 3597 ** of the sqlite3_create_collation_v2(). 3598 ** ^Collations are destroyed when they are overridden by later calls to the 3599 ** collation creation functions or when the [database connection] is closed 3600 ** using [sqlite3_close()]. 3601 ** 3602 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 3603 */ 3604 SQLITE_API int sqlite3_create_collation( 3605 sqlite3*, 3606 const char *zName, 3607 int eTextRep, 3608 void*, 3609 int(*xCompare)(void*,int,const void*,int,const void*) 3610 ); 3611 SQLITE_API int sqlite3_create_collation_v2( 3612 sqlite3*, 3613 const char *zName, 3614 int eTextRep, 3615 void*, 3616 int(*xCompare)(void*,int,const void*,int,const void*), 3617 void(*xDestroy)(void*) 3618 ); 3619 SQLITE_API int sqlite3_create_collation16( 3620 sqlite3*, 3621 const void *zName, 3622 int eTextRep, 3623 void*, 3624 int(*xCompare)(void*,int,const void*,int,const void*) 3625 ); 3626 3627 /* 3628 ** CAPI3REF: Collation Needed Callbacks 3629 ** 3630 ** ^To avoid having to register all collation sequences before a database 3631 ** can be used, a single callback function may be registered with the 3632 ** [database connection] to be invoked whenever an undefined collation 3633 ** sequence is required. 3634 ** 3635 ** ^If the function is registered using the sqlite3_collation_needed() API, 3636 ** then it is passed the names of undefined collation sequences as strings 3637 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 3638 ** the names are passed as UTF-16 in machine native byte order. 3639 ** ^A call to either function replaces the existing collation-needed callback. 3640 ** 3641 ** ^(When the callback is invoked, the first argument passed is a copy 3642 ** of the second argument to sqlite3_collation_needed() or 3643 ** sqlite3_collation_needed16(). The second argument is the database 3644 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 3645 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 3646 ** sequence function required. The fourth parameter is the name of the 3647 ** required collation sequence.)^ 3648 ** 3649 ** The callback function should register the desired collation using 3650 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 3651 ** [sqlite3_create_collation_v2()]. 3652 */ 3653 SQLITE_API int sqlite3_collation_needed( 3654 sqlite3*, 3655 void*, 3656 void(*)(void*,sqlite3*,int eTextRep,const char*) 3657 ); 3658 SQLITE_API int sqlite3_collation_needed16( 3659 sqlite3*, 3660 void*, 3661 void(*)(void*,sqlite3*,int eTextRep,const void*) 3662 ); 3663 3664 /* 3665 ** Specify the key for an encrypted database. This routine should be 3666 ** called right after sqlite3_open(). 3667 ** 3668 ** The code to implement this API is not available in the public release 3669 ** of SQLite. 3670 */ 3671 SQLITE_API int sqlite3_key( 3672 sqlite3 *db, /* Database to be rekeyed */ 3673 const void *pKey, int nKey /* The key */ 3674 ); 3675 3676 /* 3677 ** Change the key on an open database. If the current database is not 3678 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 3679 ** database is decrypted. 3680 ** 3681 ** The code to implement this API is not available in the public release 3682 ** of SQLite. 3683 */ 3684 SQLITE_API int sqlite3_rekey( 3685 sqlite3 *db, /* Database to be rekeyed */ 3686 const void *pKey, int nKey /* The new key */ 3687 ); 3688 3689 /* 3690 ** CAPI3REF: Suspend Execution For A Short Time 3691 ** 3692 ** ^The sqlite3_sleep() function causes the current thread to suspend execution 3693 ** for at least a number of milliseconds specified in its parameter. 3694 ** 3695 ** ^If the operating system does not support sleep requests with 3696 ** millisecond time resolution, then the time will be rounded up to 3697 ** the nearest second. ^The number of milliseconds of sleep actually 3698 ** requested from the operating system is returned. 3699 ** 3700 ** ^SQLite implements this interface by calling the xSleep() 3701 ** method of the default [sqlite3_vfs] object. 3702 */ 3703 SQLITE_API int sqlite3_sleep(int); 3704 3705 /* 3706 ** CAPI3REF: Name Of The Folder Holding Temporary Files 3707 ** 3708 ** ^(If this global variable is made to point to a string which is 3709 ** the name of a folder (a.k.a. directory), then all temporary files 3710 ** created by SQLite when using a built-in [sqlite3_vfs | VFS] 3711 ** will be placed in that directory.)^ ^If this variable 3712 ** is a NULL pointer, then SQLite performs a search for an appropriate 3713 ** temporary file directory. 3714 ** 3715 ** It is not safe to read or modify this variable in more than one 3716 ** thread at a time. It is not safe to read or modify this variable 3717 ** if a [database connection] is being used at the same time in a separate 3718 ** thread. 3719 ** It is intended that this variable be set once 3720 ** as part of process initialization and before any SQLite interface 3721 ** routines have been called and that this variable remain unchanged 3722 ** thereafter. 3723 ** 3724 ** ^The [temp_store_directory pragma] may modify this variable and cause 3725 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 3726 ** the [temp_store_directory pragma] always assumes that any string 3727 ** that this variable points to is held in memory obtained from 3728 ** [sqlite3_malloc] and the pragma may attempt to free that memory 3729 ** using [sqlite3_free]. 3730 ** Hence, if this variable is modified directly, either it should be 3731 ** made NULL or made to point to memory obtained from [sqlite3_malloc] 3732 ** or else the use of the [temp_store_directory pragma] should be avoided. 3733 */ 3734 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory; 3735 3736 /* 3737 ** CAPI3REF: Test For Auto-Commit Mode 3738 ** KEYWORDS: {autocommit mode} 3739 ** 3740 ** ^The sqlite3_get_autocommit() interface returns non-zero or 3741 ** zero if the given database connection is or is not in autocommit mode, 3742 ** respectively. ^Autocommit mode is on by default. 3743 ** ^Autocommit mode is disabled by a [BEGIN] statement. 3744 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 3745 ** 3746 ** If certain kinds of errors occur on a statement within a multi-statement 3747 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 3748 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 3749 ** transaction might be rolled back automatically. The only way to 3750 ** find out whether SQLite automatically rolled back the transaction after 3751 ** an error is to use this function. 3752 ** 3753 ** If another thread changes the autocommit status of the database 3754 ** connection while this routine is running, then the return value 3755 ** is undefined. 3756 */ 3757 SQLITE_API int sqlite3_get_autocommit(sqlite3*); 3758 3759 /* 3760 ** CAPI3REF: Find The Database Handle Of A Prepared Statement 3761 ** 3762 ** ^The sqlite3_db_handle interface returns the [database connection] handle 3763 ** to which a [prepared statement] belongs. ^The [database connection] 3764 ** returned by sqlite3_db_handle is the same [database connection] 3765 ** that was the first argument 3766 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 3767 ** create the statement in the first place. 3768 */ 3769 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 3770 3771 /* 3772 ** CAPI3REF: Find the next prepared statement 3773 ** 3774 ** ^This interface returns a pointer to the next [prepared statement] after 3775 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 3776 ** then this interface returns a pointer to the first prepared statement 3777 ** associated with the database connection pDb. ^If no prepared statement 3778 ** satisfies the conditions of this routine, it returns NULL. 3779 ** 3780 ** The [database connection] pointer D in a call to 3781 ** [sqlite3_next_stmt(D,S)] must refer to an open database 3782 ** connection and in particular must not be a NULL pointer. 3783 */ 3784 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 3785 3786 /* 3787 ** CAPI3REF: Commit And Rollback Notification Callbacks 3788 ** 3789 ** ^The sqlite3_commit_hook() interface registers a callback 3790 ** function to be invoked whenever a transaction is [COMMIT | committed]. 3791 ** ^Any callback set by a previous call to sqlite3_commit_hook() 3792 ** for the same database connection is overridden. 3793 ** ^The sqlite3_rollback_hook() interface registers a callback 3794 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 3795 ** ^Any callback set by a previous call to sqlite3_rollback_hook() 3796 ** for the same database connection is overridden. 3797 ** ^The pArg argument is passed through to the callback. 3798 ** ^If the callback on a commit hook function returns non-zero, 3799 ** then the commit is converted into a rollback. 3800 ** 3801 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 3802 ** return the P argument from the previous call of the same function 3803 ** on the same [database connection] D, or NULL for 3804 ** the first call for each function on D. 3805 ** 3806 ** The callback implementation must not do anything that will modify 3807 ** the database connection that invoked the callback. Any actions 3808 ** to modify the database connection must be deferred until after the 3809 ** completion of the [sqlite3_step()] call that triggered the commit 3810 ** or rollback hook in the first place. 3811 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3812 ** database connections for the meaning of "modify" in this paragraph. 3813 ** 3814 ** ^Registering a NULL function disables the callback. 3815 ** 3816 ** ^When the commit hook callback routine returns zero, the [COMMIT] 3817 ** operation is allowed to continue normally. ^If the commit hook 3818 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 3819 ** ^The rollback hook is invoked on a rollback that results from a commit 3820 ** hook returning non-zero, just as it would be with any other rollback. 3821 ** 3822 ** ^For the purposes of this API, a transaction is said to have been 3823 ** rolled back if an explicit "ROLLBACK" statement is executed, or 3824 ** an error or constraint causes an implicit rollback to occur. 3825 ** ^The rollback callback is not invoked if a transaction is 3826 ** automatically rolled back because the database connection is closed. 3827 ** ^The rollback callback is not invoked if a transaction is 3828 ** rolled back because a commit callback returned non-zero. 3829 ** 3830 ** See also the [sqlite3_update_hook()] interface. 3831 */ 3832 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 3833 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 3834 3835 /* 3836 ** CAPI3REF: Data Change Notification Callbacks 3837 ** 3838 ** ^The sqlite3_update_hook() interface registers a callback function 3839 ** with the [database connection] identified by the first argument 3840 ** to be invoked whenever a row is updated, inserted or deleted. 3841 ** ^Any callback set by a previous call to this function 3842 ** for the same database connection is overridden. 3843 ** 3844 ** ^The second argument is a pointer to the function to invoke when a 3845 ** row is updated, inserted or deleted. 3846 ** ^The first argument to the callback is a copy of the third argument 3847 ** to sqlite3_update_hook(). 3848 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 3849 ** or [SQLITE_UPDATE], depending on the operation that caused the callback 3850 ** to be invoked. 3851 ** ^The third and fourth arguments to the callback contain pointers to the 3852 ** database and table name containing the affected row. 3853 ** ^The final callback parameter is the [rowid] of the row. 3854 ** ^In the case of an update, this is the [rowid] after the update takes place. 3855 ** 3856 ** ^(The update hook is not invoked when internal system tables are 3857 ** modified (i.e. sqlite_master and sqlite_sequence).)^ 3858 ** 3859 ** ^In the current implementation, the update hook 3860 ** is not invoked when duplication rows are deleted because of an 3861 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 3862 ** invoked when rows are deleted using the [truncate optimization]. 3863 ** The exceptions defined in this paragraph might change in a future 3864 ** release of SQLite. 3865 ** 3866 ** The update hook implementation must not do anything that will modify 3867 ** the database connection that invoked the update hook. Any actions 3868 ** to modify the database connection must be deferred until after the 3869 ** completion of the [sqlite3_step()] call that triggered the update hook. 3870 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3871 ** database connections for the meaning of "modify" in this paragraph. 3872 ** 3873 ** ^The sqlite3_update_hook(D,C,P) function 3874 ** returns the P argument from the previous call 3875 ** on the same [database connection] D, or NULL for 3876 ** the first call on D. 3877 ** 3878 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 3879 ** interfaces. 3880 */ 3881 SQLITE_API void *sqlite3_update_hook( 3882 sqlite3*, 3883 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 3884 void* 3885 ); 3886 3887 /* 3888 ** CAPI3REF: Enable Or Disable Shared Pager Cache 3889 ** KEYWORDS: {shared cache} 3890 ** 3891 ** ^(This routine enables or disables the sharing of the database cache 3892 ** and schema data structures between [database connection | connections] 3893 ** to the same database. Sharing is enabled if the argument is true 3894 ** and disabled if the argument is false.)^ 3895 ** 3896 ** ^Cache sharing is enabled and disabled for an entire process. 3897 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 3898 ** sharing was enabled or disabled for each thread separately. 3899 ** 3900 ** ^(The cache sharing mode set by this interface effects all subsequent 3901 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 3902 ** Existing database connections continue use the sharing mode 3903 ** that was in effect at the time they were opened.)^ 3904 ** 3905 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 3906 ** successfully. An [error code] is returned otherwise.)^ 3907 ** 3908 ** ^Shared cache is disabled by default. But this might change in 3909 ** future releases of SQLite. Applications that care about shared 3910 ** cache setting should set it explicitly. 3911 ** 3912 ** See Also: [SQLite Shared-Cache Mode] 3913 */ 3914 SQLITE_API int sqlite3_enable_shared_cache(int); 3915 3916 /* 3917 ** CAPI3REF: Attempt To Free Heap Memory 3918 ** 3919 ** ^The sqlite3_release_memory() interface attempts to free N bytes 3920 ** of heap memory by deallocating non-essential memory allocations 3921 ** held by the database library. Memory used to cache database 3922 ** pages to improve performance is an example of non-essential memory. 3923 ** ^sqlite3_release_memory() returns the number of bytes actually freed, 3924 ** which might be more or less than the amount requested. 3925 */ 3926 SQLITE_API int sqlite3_release_memory(int); 3927 3928 /* 3929 ** CAPI3REF: Impose A Limit On Heap Size 3930 ** 3931 ** ^The sqlite3_soft_heap_limit() interface places a "soft" limit 3932 ** on the amount of heap memory that may be allocated by SQLite. 3933 ** ^If an internal allocation is requested that would exceed the 3934 ** soft heap limit, [sqlite3_release_memory()] is invoked one or 3935 ** more times to free up some space before the allocation is performed. 3936 ** 3937 ** ^The limit is called "soft" because if [sqlite3_release_memory()] 3938 ** cannot free sufficient memory to prevent the limit from being exceeded, 3939 ** the memory is allocated anyway and the current operation proceeds. 3940 ** 3941 ** ^A negative or zero value for N means that there is no soft heap limit and 3942 ** [sqlite3_release_memory()] will only be called when memory is exhausted. 3943 ** ^The default value for the soft heap limit is zero. 3944 ** 3945 ** ^(SQLite makes a best effort to honor the soft heap limit. 3946 ** But if the soft heap limit cannot be honored, execution will 3947 ** continue without error or notification.)^ This is why the limit is 3948 ** called a "soft" limit. It is advisory only. 3949 ** 3950 ** Prior to SQLite version 3.5.0, this routine only constrained the memory 3951 ** allocated by a single thread - the same thread in which this routine 3952 ** runs. Beginning with SQLite version 3.5.0, the soft heap limit is 3953 ** applied to all threads. The value specified for the soft heap limit 3954 ** is an upper bound on the total memory allocation for all threads. In 3955 ** version 3.5.0 there is no mechanism for limiting the heap usage for 3956 ** individual threads. 3957 */ 3958 SQLITE_API void sqlite3_soft_heap_limit(int); 3959 3960 /* 3961 ** CAPI3REF: Extract Metadata About A Column Of A Table 3962 ** 3963 ** ^This routine returns metadata about a specific column of a specific 3964 ** database table accessible using the [database connection] handle 3965 ** passed as the first function argument. 3966 ** 3967 ** ^The column is identified by the second, third and fourth parameters to 3968 ** this function. ^The second parameter is either the name of the database 3969 ** (i.e. "main", "temp", or an attached database) containing the specified 3970 ** table or NULL. ^If it is NULL, then all attached databases are searched 3971 ** for the table using the same algorithm used by the database engine to 3972 ** resolve unqualified table references. 3973 ** 3974 ** ^The third and fourth parameters to this function are the table and column 3975 ** name of the desired column, respectively. Neither of these parameters 3976 ** may be NULL. 3977 ** 3978 ** ^Metadata is returned by writing to the memory locations passed as the 5th 3979 ** and subsequent parameters to this function. ^Any of these arguments may be 3980 ** NULL, in which case the corresponding element of metadata is omitted. 3981 ** 3982 ** ^(<blockquote> 3983 ** <table border="1"> 3984 ** <tr><th> Parameter <th> Output<br>Type <th> Description 3985 ** 3986 ** <tr><td> 5th <td> const char* <td> Data type 3987 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence 3988 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 3989 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 3990 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 3991 ** </table> 3992 ** </blockquote>)^ 3993 ** 3994 ** ^The memory pointed to by the character pointers returned for the 3995 ** declaration type and collation sequence is valid only until the next 3996 ** call to any SQLite API function. 3997 ** 3998 ** ^If the specified table is actually a view, an [error code] is returned. 3999 ** 4000 ** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4001 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4002 ** parameters are set for the explicitly declared column. ^(If there is no 4003 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4004 ** parameters are set as follows: 4005 ** 4006 ** <pre> 4007 ** data type: "INTEGER" 4008 ** collation sequence: "BINARY" 4009 ** not null: 0 4010 ** primary key: 1 4011 ** auto increment: 0 4012 ** </pre>)^ 4013 ** 4014 ** ^(This function may load one or more schemas from database files. If an 4015 ** error occurs during this process, or if the requested table or column 4016 ** cannot be found, an [error code] is returned and an error message left 4017 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4018 ** 4019 ** ^This API is only available if the library was compiled with the 4020 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4021 */ 4022 SQLITE_API int sqlite3_table_column_metadata( 4023 sqlite3 *db, /* Connection handle */ 4024 const char *zDbName, /* Database name or NULL */ 4025 const char *zTableName, /* Table name */ 4026 const char *zColumnName, /* Column name */ 4027 char const **pzDataType, /* OUTPUT: Declared data type */ 4028 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4029 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4030 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4031 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4032 ); 4033 4034 /* 4035 ** CAPI3REF: Load An Extension 4036 ** 4037 ** ^This interface loads an SQLite extension library from the named file. 4038 ** 4039 ** ^The sqlite3_load_extension() interface attempts to load an 4040 ** SQLite extension library contained in the file zFile. 4041 ** 4042 ** ^The entry point is zProc. 4043 ** ^zProc may be 0, in which case the name of the entry point 4044 ** defaults to "sqlite3_extension_init". 4045 ** ^The sqlite3_load_extension() interface returns 4046 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4047 ** ^If an error occurs and pzErrMsg is not 0, then the 4048 ** [sqlite3_load_extension()] interface shall attempt to 4049 ** fill *pzErrMsg with error message text stored in memory 4050 ** obtained from [sqlite3_malloc()]. The calling function 4051 ** should free this memory by calling [sqlite3_free()]. 4052 ** 4053 ** ^Extension loading must be enabled using 4054 ** [sqlite3_enable_load_extension()] prior to calling this API, 4055 ** otherwise an error will be returned. 4056 ** 4057 ** See also the [load_extension() SQL function]. 4058 */ 4059 SQLITE_API int sqlite3_load_extension( 4060 sqlite3 *db, /* Load the extension into this database connection */ 4061 const char *zFile, /* Name of the shared library containing extension */ 4062 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4063 char **pzErrMsg /* Put error message here if not 0 */ 4064 ); 4065 4066 /* 4067 ** CAPI3REF: Enable Or Disable Extension Loading 4068 ** 4069 ** ^So as not to open security holes in older applications that are 4070 ** unprepared to deal with extension loading, and as a means of disabling 4071 ** extension loading while evaluating user-entered SQL, the following API 4072 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4073 ** 4074 ** ^Extension loading is off by default. See ticket #1863. 4075 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1 4076 ** to turn extension loading on and call it with onoff==0 to turn 4077 ** it back off again. 4078 */ 4079 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4080 4081 /* 4082 ** CAPI3REF: Automatically Load An Extensions 4083 ** 4084 ** ^This API can be invoked at program startup in order to register 4085 ** one or more statically linked extensions that will be available 4086 ** to all new [database connections]. 4087 ** 4088 ** ^(This routine stores a pointer to the extension entry point 4089 ** in an array that is obtained from [sqlite3_malloc()]. That memory 4090 ** is deallocated by [sqlite3_reset_auto_extension()].)^ 4091 ** 4092 ** ^This function registers an extension entry point that is 4093 ** automatically invoked whenever a new [database connection] 4094 ** is opened using [sqlite3_open()], [sqlite3_open16()], 4095 ** or [sqlite3_open_v2()]. 4096 ** ^Duplicate extensions are detected so calling this routine 4097 ** multiple times with the same extension is harmless. 4098 ** ^Automatic extensions apply across all threads. 4099 */ 4100 SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4101 4102 /* 4103 ** CAPI3REF: Reset Automatic Extension Loading 4104 ** 4105 ** ^(This function disables all previously registered automatic 4106 ** extensions. It undoes the effect of all prior 4107 ** [sqlite3_auto_extension()] calls.)^ 4108 ** 4109 ** ^This function disables automatic extensions in all threads. 4110 */ 4111 SQLITE_API void sqlite3_reset_auto_extension(void); 4112 4113 /* 4114 ****** EXPERIMENTAL - subject to change without notice ************** 4115 ** 4116 ** The interface to the virtual-table mechanism is currently considered 4117 ** to be experimental. The interface might change in incompatible ways. 4118 ** If this is a problem for you, do not use the interface at this time. 4119 ** 4120 ** When the virtual-table mechanism stabilizes, we will declare the 4121 ** interface fixed, support it indefinitely, and remove this comment. 4122 */ 4123 4124 /* 4125 ** Structures used by the virtual table interface 4126 */ 4127 typedef struct sqlite3_vtab sqlite3_vtab; 4128 typedef struct sqlite3_index_info sqlite3_index_info; 4129 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4130 typedef struct sqlite3_module sqlite3_module; 4131 4132 /* 4133 ** CAPI3REF: Virtual Table Object 4134 ** KEYWORDS: sqlite3_module {virtual table module} 4135 ** EXPERIMENTAL 4136 ** 4137 ** This structure, sometimes called a a "virtual table module", 4138 ** defines the implementation of a [virtual tables]. 4139 ** This structure consists mostly of methods for the module. 4140 ** 4141 ** ^A virtual table module is created by filling in a persistent 4142 ** instance of this structure and passing a pointer to that instance 4143 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4144 ** ^The registration remains valid until it is replaced by a different 4145 ** module or until the [database connection] closes. The content 4146 ** of this structure must not change while it is registered with 4147 ** any database connection. 4148 */ 4149 struct sqlite3_module { 4150 int iVersion; 4151 int (*xCreate)(sqlite3*, void *pAux, 4152 int argc, const char *const*argv, 4153 sqlite3_vtab **ppVTab, char**); 4154 int (*xConnect)(sqlite3*, void *pAux, 4155 int argc, const char *const*argv, 4156 sqlite3_vtab **ppVTab, char**); 4157 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4158 int (*xDisconnect)(sqlite3_vtab *pVTab); 4159 int (*xDestroy)(sqlite3_vtab *pVTab); 4160 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4161 int (*xClose)(sqlite3_vtab_cursor*); 4162 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4163 int argc, sqlite3_value **argv); 4164 int (*xNext)(sqlite3_vtab_cursor*); 4165 int (*xEof)(sqlite3_vtab_cursor*); 4166 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4167 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4168 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4169 int (*xBegin)(sqlite3_vtab *pVTab); 4170 int (*xSync)(sqlite3_vtab *pVTab); 4171 int (*xCommit)(sqlite3_vtab *pVTab); 4172 int (*xRollback)(sqlite3_vtab *pVTab); 4173 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4174 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4175 void **ppArg); 4176 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4177 }; 4178 4179 /* 4180 ** CAPI3REF: Virtual Table Indexing Information 4181 ** KEYWORDS: sqlite3_index_info 4182 ** EXPERIMENTAL 4183 ** 4184 ** The sqlite3_index_info structure and its substructures is used to 4185 ** pass information into and receive the reply from the [xBestIndex] 4186 ** method of a [virtual table module]. The fields under **Inputs** are the 4187 ** inputs to xBestIndex and are read-only. xBestIndex inserts its 4188 ** results into the **Outputs** fields. 4189 ** 4190 ** ^(The aConstraint[] array records WHERE clause constraints of the form: 4191 ** 4192 ** <pre>column OP expr</pre> 4193 ** 4194 ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 4195 ** stored in aConstraint[].op.)^ ^(The index of the column is stored in 4196 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 4197 ** expr on the right-hand side can be evaluated (and thus the constraint 4198 ** is usable) and false if it cannot.)^ 4199 ** 4200 ** ^The optimizer automatically inverts terms of the form "expr OP column" 4201 ** and makes other simplifications to the WHERE clause in an attempt to 4202 ** get as many WHERE clause terms into the form shown above as possible. 4203 ** ^The aConstraint[] array only reports WHERE clause terms that are 4204 ** relevant to the particular virtual table being queried. 4205 ** 4206 ** ^Information about the ORDER BY clause is stored in aOrderBy[]. 4207 ** ^Each term of aOrderBy records a column of the ORDER BY clause. 4208 ** 4209 ** The [xBestIndex] method must fill aConstraintUsage[] with information 4210 ** about what parameters to pass to xFilter. ^If argvIndex>0 then 4211 ** the right-hand side of the corresponding aConstraint[] is evaluated 4212 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 4213 ** is true, then the constraint is assumed to be fully handled by the 4214 ** virtual table and is not checked again by SQLite.)^ 4215 ** 4216 ** ^The idxNum and idxPtr values are recorded and passed into the 4217 ** [xFilter] method. 4218 ** ^[sqlite3_free()] is used to free idxPtr if and only if 4219 ** needToFreeIdxPtr is true. 4220 ** 4221 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 4222 ** the correct order to satisfy the ORDER BY clause so that no separate 4223 ** sorting step is required. 4224 ** 4225 ** ^The estimatedCost value is an estimate of the cost of doing the 4226 ** particular lookup. A full scan of a table with N entries should have 4227 ** a cost of N. A binary search of a table of N entries should have a 4228 ** cost of approximately log(N). 4229 */ 4230 struct sqlite3_index_info { 4231 /* Inputs */ 4232 int nConstraint; /* Number of entries in aConstraint */ 4233 struct sqlite3_index_constraint { 4234 int iColumn; /* Column on left-hand side of constraint */ 4235 unsigned char op; /* Constraint operator */ 4236 unsigned char usable; /* True if this constraint is usable */ 4237 int iTermOffset; /* Used internally - xBestIndex should ignore */ 4238 } *aConstraint; /* Table of WHERE clause constraints */ 4239 int nOrderBy; /* Number of terms in the ORDER BY clause */ 4240 struct sqlite3_index_orderby { 4241 int iColumn; /* Column number */ 4242 unsigned char desc; /* True for DESC. False for ASC. */ 4243 } *aOrderBy; /* The ORDER BY clause */ 4244 /* Outputs */ 4245 struct sqlite3_index_constraint_usage { 4246 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 4247 unsigned char omit; /* Do not code a test for this constraint */ 4248 } *aConstraintUsage; 4249 int idxNum; /* Number used to identify the index */ 4250 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 4251 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 4252 int orderByConsumed; /* True if output is already ordered */ 4253 double estimatedCost; /* Estimated cost of using this index */ 4254 }; 4255 #define SQLITE_INDEX_CONSTRAINT_EQ 2 4256 #define SQLITE_INDEX_CONSTRAINT_GT 4 4257 #define SQLITE_INDEX_CONSTRAINT_LE 8 4258 #define SQLITE_INDEX_CONSTRAINT_LT 16 4259 #define SQLITE_INDEX_CONSTRAINT_GE 32 4260 #define SQLITE_INDEX_CONSTRAINT_MATCH 64 4261 4262 /* 4263 ** CAPI3REF: Register A Virtual Table Implementation 4264 ** EXPERIMENTAL 4265 ** 4266 ** ^These routines are used to register a new [virtual table module] name. 4267 ** ^Module names must be registered before 4268 ** creating a new [virtual table] using the module and before using a 4269 ** preexisting [virtual table] for the module. 4270 ** 4271 ** ^The module name is registered on the [database connection] specified 4272 ** by the first parameter. ^The name of the module is given by the 4273 ** second parameter. ^The third parameter is a pointer to 4274 ** the implementation of the [virtual table module]. ^The fourth 4275 ** parameter is an arbitrary client data pointer that is passed through 4276 ** into the [xCreate] and [xConnect] methods of the virtual table module 4277 ** when a new virtual table is be being created or reinitialized. 4278 ** 4279 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which 4280 ** is a pointer to a destructor for the pClientData. ^SQLite will 4281 ** invoke the destructor function (if it is not NULL) when SQLite 4282 ** no longer needs the pClientData pointer. ^The sqlite3_create_module() 4283 ** interface is equivalent to sqlite3_create_module_v2() with a NULL 4284 ** destructor. 4285 */ 4286 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_create_module( 4287 sqlite3 *db, /* SQLite connection to register module with */ 4288 const char *zName, /* Name of the module */ 4289 const sqlite3_module *p, /* Methods for the module */ 4290 void *pClientData /* Client data for xCreate/xConnect */ 4291 ); 4292 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_create_module_v2( 4293 sqlite3 *db, /* SQLite connection to register module with */ 4294 const char *zName, /* Name of the module */ 4295 const sqlite3_module *p, /* Methods for the module */ 4296 void *pClientData, /* Client data for xCreate/xConnect */ 4297 void(*xDestroy)(void*) /* Module destructor function */ 4298 ); 4299 4300 /* 4301 ** CAPI3REF: Virtual Table Instance Object 4302 ** KEYWORDS: sqlite3_vtab 4303 ** EXPERIMENTAL 4304 ** 4305 ** Every [virtual table module] implementation uses a subclass 4306 ** of this object to describe a particular instance 4307 ** of the [virtual table]. Each subclass will 4308 ** be tailored to the specific needs of the module implementation. 4309 ** The purpose of this superclass is to define certain fields that are 4310 ** common to all module implementations. 4311 ** 4312 ** ^Virtual tables methods can set an error message by assigning a 4313 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 4314 ** take care that any prior string is freed by a call to [sqlite3_free()] 4315 ** prior to assigning a new string to zErrMsg. ^After the error message 4316 ** is delivered up to the client application, the string will be automatically 4317 ** freed by sqlite3_free() and the zErrMsg field will be zeroed. 4318 */ 4319 struct sqlite3_vtab { 4320 const sqlite3_module *pModule; /* The module for this virtual table */ 4321 int nRef; /* NO LONGER USED */ 4322 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 4323 /* Virtual table implementations will typically add additional fields */ 4324 }; 4325 4326 /* 4327 ** CAPI3REF: Virtual Table Cursor Object 4328 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 4329 ** EXPERIMENTAL 4330 ** 4331 ** Every [virtual table module] implementation uses a subclass of the 4332 ** following structure to describe cursors that point into the 4333 ** [virtual table] and are used 4334 ** to loop through the virtual table. Cursors are created using the 4335 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 4336 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used 4337 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 4338 ** of the module. Each module implementation will define 4339 ** the content of a cursor structure to suit its own needs. 4340 ** 4341 ** This superclass exists in order to define fields of the cursor that 4342 ** are common to all implementations. 4343 */ 4344 struct sqlite3_vtab_cursor { 4345 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 4346 /* Virtual table implementations will typically add additional fields */ 4347 }; 4348 4349 /* 4350 ** CAPI3REF: Declare The Schema Of A Virtual Table 4351 ** EXPERIMENTAL 4352 ** 4353 ** ^The [xCreate] and [xConnect] methods of a 4354 ** [virtual table module] call this interface 4355 ** to declare the format (the names and datatypes of the columns) of 4356 ** the virtual tables they implement. 4357 */ 4358 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 4359 4360 /* 4361 ** CAPI3REF: Overload A Function For A Virtual Table 4362 ** EXPERIMENTAL 4363 ** 4364 ** ^(Virtual tables can provide alternative implementations of functions 4365 ** using the [xFindFunction] method of the [virtual table module]. 4366 ** But global versions of those functions 4367 ** must exist in order to be overloaded.)^ 4368 ** 4369 ** ^(This API makes sure a global version of a function with a particular 4370 ** name and number of parameters exists. If no such function exists 4371 ** before this API is called, a new function is created.)^ ^The implementation 4372 ** of the new function always causes an exception to be thrown. So 4373 ** the new function is not good for anything by itself. Its only 4374 ** purpose is to be a placeholder function that can be overloaded 4375 ** by a [virtual table]. 4376 */ 4377 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 4378 4379 /* 4380 ** The interface to the virtual-table mechanism defined above (back up 4381 ** to a comment remarkably similar to this one) is currently considered 4382 ** to be experimental. The interface might change in incompatible ways. 4383 ** If this is a problem for you, do not use the interface at this time. 4384 ** 4385 ** When the virtual-table mechanism stabilizes, we will declare the 4386 ** interface fixed, support it indefinitely, and remove this comment. 4387 ** 4388 ****** EXPERIMENTAL - subject to change without notice ************** 4389 */ 4390 4391 /* 4392 ** CAPI3REF: A Handle To An Open BLOB 4393 ** KEYWORDS: {BLOB handle} {BLOB handles} 4394 ** 4395 ** An instance of this object represents an open BLOB on which 4396 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 4397 ** ^Objects of this type are created by [sqlite3_blob_open()] 4398 ** and destroyed by [sqlite3_blob_close()]. 4399 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 4400 ** can be used to read or write small subsections of the BLOB. 4401 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 4402 */ 4403 typedef struct sqlite3_blob sqlite3_blob; 4404 4405 /* 4406 ** CAPI3REF: Open A BLOB For Incremental I/O 4407 ** 4408 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 4409 ** in row iRow, column zColumn, table zTable in database zDb; 4410 ** in other words, the same BLOB that would be selected by: 4411 ** 4412 ** <pre> 4413 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 4414 ** </pre>)^ 4415 ** 4416 ** ^If the flags parameter is non-zero, then the BLOB is opened for read 4417 ** and write access. ^If it is zero, the BLOB is opened for read access. 4418 ** ^It is not possible to open a column that is part of an index or primary 4419 ** key for writing. ^If [foreign key constraints] are enabled, it is 4420 ** not possible to open a column that is part of a [child key] for writing. 4421 ** 4422 ** ^Note that the database name is not the filename that contains 4423 ** the database but rather the symbolic name of the database that 4424 ** appears after the AS keyword when the database is connected using [ATTACH]. 4425 ** ^For the main database file, the database name is "main". 4426 ** ^For TEMP tables, the database name is "temp". 4427 ** 4428 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 4429 ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 4430 ** to be a null pointer.)^ 4431 ** ^This function sets the [database connection] error code and message 4432 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 4433 ** functions. ^Note that the *ppBlob variable is always initialized in a 4434 ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 4435 ** regardless of the success or failure of this routine. 4436 ** 4437 ** ^(If the row that a BLOB handle points to is modified by an 4438 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 4439 ** then the BLOB handle is marked as "expired". 4440 ** This is true if any column of the row is changed, even a column 4441 ** other than the one the BLOB handle is open on.)^ 4442 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 4443 ** a expired BLOB handle fail with an return code of [SQLITE_ABORT]. 4444 ** ^(Changes written into a BLOB prior to the BLOB expiring are not 4445 ** rolled back by the expiration of the BLOB. Such changes will eventually 4446 ** commit if the transaction continues to completion.)^ 4447 ** 4448 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 4449 ** the opened blob. ^The size of a blob may not be changed by this 4450 ** interface. Use the [UPDATE] SQL command to change the size of a 4451 ** blob. 4452 ** 4453 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 4454 ** and the built-in [zeroblob] SQL function can be used, if desired, 4455 ** to create an empty, zero-filled blob in which to read or write using 4456 ** this interface. 4457 ** 4458 ** To avoid a resource leak, every open [BLOB handle] should eventually 4459 ** be released by a call to [sqlite3_blob_close()]. 4460 */ 4461 SQLITE_API int sqlite3_blob_open( 4462 sqlite3*, 4463 const char *zDb, 4464 const char *zTable, 4465 const char *zColumn, 4466 sqlite3_int64 iRow, 4467 int flags, 4468 sqlite3_blob **ppBlob 4469 ); 4470 4471 /* 4472 ** CAPI3REF: Close A BLOB Handle 4473 ** 4474 ** ^Closes an open [BLOB handle]. 4475 ** 4476 ** ^Closing a BLOB shall cause the current transaction to commit 4477 ** if there are no other BLOBs, no pending prepared statements, and the 4478 ** database connection is in [autocommit mode]. 4479 ** ^If any writes were made to the BLOB, they might be held in cache 4480 ** until the close operation if they will fit. 4481 ** 4482 ** ^(Closing the BLOB often forces the changes 4483 ** out to disk and so if any I/O errors occur, they will likely occur 4484 ** at the time when the BLOB is closed. Any errors that occur during 4485 ** closing are reported as a non-zero return value.)^ 4486 ** 4487 ** ^(The BLOB is closed unconditionally. Even if this routine returns 4488 ** an error code, the BLOB is still closed.)^ 4489 ** 4490 ** ^Calling this routine with a null pointer (such as would be returned 4491 ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 4492 */ 4493 SQLITE_API int sqlite3_blob_close(sqlite3_blob *); 4494 4495 /* 4496 ** CAPI3REF: Return The Size Of An Open BLOB 4497 ** 4498 ** ^Returns the size in bytes of the BLOB accessible via the 4499 ** successfully opened [BLOB handle] in its only argument. ^The 4500 ** incremental blob I/O routines can only read or overwriting existing 4501 ** blob content; they cannot change the size of a blob. 4502 ** 4503 ** This routine only works on a [BLOB handle] which has been created 4504 ** by a prior successful call to [sqlite3_blob_open()] and which has not 4505 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4506 ** to this routine results in undefined and probably undesirable behavior. 4507 */ 4508 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *); 4509 4510 /* 4511 ** CAPI3REF: Read Data From A BLOB Incrementally 4512 ** 4513 ** ^(This function is used to read data from an open [BLOB handle] into a 4514 ** caller-supplied buffer. N bytes of data are copied into buffer Z 4515 ** from the open BLOB, starting at offset iOffset.)^ 4516 ** 4517 ** ^If offset iOffset is less than N bytes from the end of the BLOB, 4518 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 4519 ** less than zero, [SQLITE_ERROR] is returned and no data is read. 4520 ** ^The size of the blob (and hence the maximum value of N+iOffset) 4521 ** can be determined using the [sqlite3_blob_bytes()] interface. 4522 ** 4523 ** ^An attempt to read from an expired [BLOB handle] fails with an 4524 ** error code of [SQLITE_ABORT]. 4525 ** 4526 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 4527 ** Otherwise, an [error code] or an [extended error code] is returned.)^ 4528 ** 4529 ** This routine only works on a [BLOB handle] which has been created 4530 ** by a prior successful call to [sqlite3_blob_open()] and which has not 4531 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4532 ** to this routine results in undefined and probably undesirable behavior. 4533 ** 4534 ** See also: [sqlite3_blob_write()]. 4535 */ 4536 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 4537 4538 /* 4539 ** CAPI3REF: Write Data Into A BLOB Incrementally 4540 ** 4541 ** ^This function is used to write data into an open [BLOB handle] from a 4542 ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 4543 ** into the open BLOB, starting at offset iOffset. 4544 ** 4545 ** ^If the [BLOB handle] passed as the first argument was not opened for 4546 ** writing (the flags parameter to [sqlite3_blob_open()] was zero), 4547 ** this function returns [SQLITE_READONLY]. 4548 ** 4549 ** ^This function may only modify the contents of the BLOB; it is 4550 ** not possible to increase the size of a BLOB using this API. 4551 ** ^If offset iOffset is less than N bytes from the end of the BLOB, 4552 ** [SQLITE_ERROR] is returned and no data is written. ^If N is 4553 ** less than zero [SQLITE_ERROR] is returned and no data is written. 4554 ** The size of the BLOB (and hence the maximum value of N+iOffset) 4555 ** can be determined using the [sqlite3_blob_bytes()] interface. 4556 ** 4557 ** ^An attempt to write to an expired [BLOB handle] fails with an 4558 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 4559 ** before the [BLOB handle] expired are not rolled back by the 4560 ** expiration of the handle, though of course those changes might 4561 ** have been overwritten by the statement that expired the BLOB handle 4562 ** or by other independent statements. 4563 ** 4564 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 4565 ** Otherwise, an [error code] or an [extended error code] is returned.)^ 4566 ** 4567 ** This routine only works on a [BLOB handle] which has been created 4568 ** by a prior successful call to [sqlite3_blob_open()] and which has not 4569 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4570 ** to this routine results in undefined and probably undesirable behavior. 4571 ** 4572 ** See also: [sqlite3_blob_read()]. 4573 */ 4574 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 4575 4576 /* 4577 ** CAPI3REF: Virtual File System Objects 4578 ** 4579 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object 4580 ** that SQLite uses to interact 4581 ** with the underlying operating system. Most SQLite builds come with a 4582 ** single default VFS that is appropriate for the host computer. 4583 ** New VFSes can be registered and existing VFSes can be unregistered. 4584 ** The following interfaces are provided. 4585 ** 4586 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 4587 ** ^Names are case sensitive. 4588 ** ^Names are zero-terminated UTF-8 strings. 4589 ** ^If there is no match, a NULL pointer is returned. 4590 ** ^If zVfsName is NULL then the default VFS is returned. 4591 ** 4592 ** ^New VFSes are registered with sqlite3_vfs_register(). 4593 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 4594 ** ^The same VFS can be registered multiple times without injury. 4595 ** ^To make an existing VFS into the default VFS, register it again 4596 ** with the makeDflt flag set. If two different VFSes with the 4597 ** same name are registered, the behavior is undefined. If a 4598 ** VFS is registered with a name that is NULL or an empty string, 4599 ** then the behavior is undefined. 4600 ** 4601 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 4602 ** ^(If the default VFS is unregistered, another VFS is chosen as 4603 ** the default. The choice for the new VFS is arbitrary.)^ 4604 */ 4605 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 4606 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 4607 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*); 4608 4609 /* 4610 ** CAPI3REF: Mutexes 4611 ** 4612 ** The SQLite core uses these routines for thread 4613 ** synchronization. Though they are intended for internal 4614 ** use by SQLite, code that links against SQLite is 4615 ** permitted to use any of these routines. 4616 ** 4617 ** The SQLite source code contains multiple implementations 4618 ** of these mutex routines. An appropriate implementation 4619 ** is selected automatically at compile-time. ^(The following 4620 ** implementations are available in the SQLite core: 4621 ** 4622 ** <ul> 4623 ** <li> SQLITE_MUTEX_OS2 4624 ** <li> SQLITE_MUTEX_PTHREAD 4625 ** <li> SQLITE_MUTEX_W32 4626 ** <li> SQLITE_MUTEX_NOOP 4627 ** </ul>)^ 4628 ** 4629 ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 4630 ** that does no real locking and is appropriate for use in 4631 ** a single-threaded application. ^The SQLITE_MUTEX_OS2, 4632 ** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations 4633 ** are appropriate for use on OS/2, Unix, and Windows. 4634 ** 4635 ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 4636 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 4637 ** implementation is included with the library. In this case the 4638 ** application must supply a custom mutex implementation using the 4639 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 4640 ** before calling sqlite3_initialize() or any other public sqlite3_ 4641 ** function that calls sqlite3_initialize().)^ 4642 ** 4643 ** ^The sqlite3_mutex_alloc() routine allocates a new 4644 ** mutex and returns a pointer to it. ^If it returns NULL 4645 ** that means that a mutex could not be allocated. ^SQLite 4646 ** will unwind its stack and return an error. ^(The argument 4647 ** to sqlite3_mutex_alloc() is one of these integer constants: 4648 ** 4649 ** <ul> 4650 ** <li> SQLITE_MUTEX_FAST 4651 ** <li> SQLITE_MUTEX_RECURSIVE 4652 ** <li> SQLITE_MUTEX_STATIC_MASTER 4653 ** <li> SQLITE_MUTEX_STATIC_MEM 4654 ** <li> SQLITE_MUTEX_STATIC_MEM2 4655 ** <li> SQLITE_MUTEX_STATIC_PRNG 4656 ** <li> SQLITE_MUTEX_STATIC_LRU 4657 ** <li> SQLITE_MUTEX_STATIC_LRU2 4658 ** </ul>)^ 4659 ** 4660 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 4661 ** cause sqlite3_mutex_alloc() to create 4662 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 4663 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 4664 ** The mutex implementation does not need to make a distinction 4665 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 4666 ** not want to. ^SQLite will only request a recursive mutex in 4667 ** cases where it really needs one. ^If a faster non-recursive mutex 4668 ** implementation is available on the host platform, the mutex subsystem 4669 ** might return such a mutex in response to SQLITE_MUTEX_FAST. 4670 ** 4671 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 4672 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 4673 ** a pointer to a static preexisting mutex. ^Six static mutexes are 4674 ** used by the current version of SQLite. Future versions of SQLite 4675 ** may add additional static mutexes. Static mutexes are for internal 4676 ** use by SQLite only. Applications that use SQLite mutexes should 4677 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 4678 ** SQLITE_MUTEX_RECURSIVE. 4679 ** 4680 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 4681 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 4682 ** returns a different mutex on every call. ^But for the static 4683 ** mutex types, the same mutex is returned on every call that has 4684 ** the same type number. 4685 ** 4686 ** ^The sqlite3_mutex_free() routine deallocates a previously 4687 ** allocated dynamic mutex. ^SQLite is careful to deallocate every 4688 ** dynamic mutex that it allocates. The dynamic mutexes must not be in 4689 ** use when they are deallocated. Attempting to deallocate a static 4690 ** mutex results in undefined behavior. ^SQLite never deallocates 4691 ** a static mutex. 4692 ** 4693 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 4694 ** to enter a mutex. ^If another thread is already within the mutex, 4695 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 4696 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 4697 ** upon successful entry. ^(Mutexes created using 4698 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 4699 ** In such cases the, 4700 ** mutex must be exited an equal number of times before another thread 4701 ** can enter.)^ ^(If the same thread tries to enter any other 4702 ** kind of mutex more than once, the behavior is undefined. 4703 ** SQLite will never exhibit 4704 ** such behavior in its own use of mutexes.)^ 4705 ** 4706 ** ^(Some systems (for example, Windows 95) do not support the operation 4707 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 4708 ** will always return SQLITE_BUSY. The SQLite core only ever uses 4709 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 4710 ** 4711 ** ^The sqlite3_mutex_leave() routine exits a mutex that was 4712 ** previously entered by the same thread. ^(The behavior 4713 ** is undefined if the mutex is not currently entered by the 4714 ** calling thread or is not currently allocated. SQLite will 4715 ** never do either.)^ 4716 ** 4717 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 4718 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines 4719 ** behave as no-ops. 4720 ** 4721 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 4722 */ 4723 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int); 4724 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*); 4725 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*); 4726 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*); 4727 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*); 4728 4729 /* 4730 ** CAPI3REF: Mutex Methods Object 4731 ** EXPERIMENTAL 4732 ** 4733 ** An instance of this structure defines the low-level routines 4734 ** used to allocate and use mutexes. 4735 ** 4736 ** Usually, the default mutex implementations provided by SQLite are 4737 ** sufficient, however the user has the option of substituting a custom 4738 ** implementation for specialized deployments or systems for which SQLite 4739 ** does not provide a suitable implementation. In this case, the user 4740 ** creates and populates an instance of this structure to pass 4741 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 4742 ** Additionally, an instance of this structure can be used as an 4743 ** output variable when querying the system for the current mutex 4744 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 4745 ** 4746 ** ^The xMutexInit method defined by this structure is invoked as 4747 ** part of system initialization by the sqlite3_initialize() function. 4748 ** ^The xMutexInit routine is calle by SQLite exactly once for each 4749 ** effective call to [sqlite3_initialize()]. 4750 ** 4751 ** ^The xMutexEnd method defined by this structure is invoked as 4752 ** part of system shutdown by the sqlite3_shutdown() function. The 4753 ** implementation of this method is expected to release all outstanding 4754 ** resources obtained by the mutex methods implementation, especially 4755 ** those obtained by the xMutexInit method. ^The xMutexEnd() 4756 ** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 4757 ** 4758 ** ^(The remaining seven methods defined by this structure (xMutexAlloc, 4759 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 4760 ** xMutexNotheld) implement the following interfaces (respectively): 4761 ** 4762 ** <ul> 4763 ** <li> [sqlite3_mutex_alloc()] </li> 4764 ** <li> [sqlite3_mutex_free()] </li> 4765 ** <li> [sqlite3_mutex_enter()] </li> 4766 ** <li> [sqlite3_mutex_try()] </li> 4767 ** <li> [sqlite3_mutex_leave()] </li> 4768 ** <li> [sqlite3_mutex_held()] </li> 4769 ** <li> [sqlite3_mutex_notheld()] </li> 4770 ** </ul>)^ 4771 ** 4772 ** The only difference is that the public sqlite3_XXX functions enumerated 4773 ** above silently ignore any invocations that pass a NULL pointer instead 4774 ** of a valid mutex handle. The implementations of the methods defined 4775 ** by this structure are not required to handle this case, the results 4776 ** of passing a NULL pointer instead of a valid mutex handle are undefined 4777 ** (i.e. it is acceptable to provide an implementation that segfaults if 4778 ** it is passed a NULL pointer). 4779 ** 4780 ** The xMutexInit() method must be threadsafe. ^It must be harmless to 4781 ** invoke xMutexInit() mutiple times within the same process and without 4782 ** intervening calls to xMutexEnd(). Second and subsequent calls to 4783 ** xMutexInit() must be no-ops. 4784 ** 4785 ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 4786 ** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 4787 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 4788 ** memory allocation for a fast or recursive mutex. 4789 ** 4790 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 4791 ** called, but only if the prior call to xMutexInit returned SQLITE_OK. 4792 ** If xMutexInit fails in any way, it is expected to clean up after itself 4793 ** prior to returning. 4794 */ 4795 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 4796 struct sqlite3_mutex_methods { 4797 int (*xMutexInit)(void); 4798 int (*xMutexEnd)(void); 4799 sqlite3_mutex *(*xMutexAlloc)(int); 4800 void (*xMutexFree)(sqlite3_mutex *); 4801 void (*xMutexEnter)(sqlite3_mutex *); 4802 int (*xMutexTry)(sqlite3_mutex *); 4803 void (*xMutexLeave)(sqlite3_mutex *); 4804 int (*xMutexHeld)(sqlite3_mutex *); 4805 int (*xMutexNotheld)(sqlite3_mutex *); 4806 }; 4807 4808 /* 4809 ** CAPI3REF: Mutex Verification Routines 4810 ** 4811 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 4812 ** are intended for use inside assert() statements. ^The SQLite core 4813 ** never uses these routines except inside an assert() and applications 4814 ** are advised to follow the lead of the core. ^The SQLite core only 4815 ** provides implementations for these routines when it is compiled 4816 ** with the SQLITE_DEBUG flag. ^External mutex implementations 4817 ** are only required to provide these routines if SQLITE_DEBUG is 4818 ** defined and if NDEBUG is not defined. 4819 ** 4820 ** ^These routines should return true if the mutex in their argument 4821 ** is held or not held, respectively, by the calling thread. 4822 ** 4823 ** ^The implementation is not required to provided versions of these 4824 ** routines that actually work. If the implementation does not provide working 4825 ** versions of these routines, it should at least provide stubs that always 4826 ** return true so that one does not get spurious assertion failures. 4827 ** 4828 ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 4829 ** the routine should return 1. This seems counter-intuitive since 4830 ** clearly the mutex cannot be held if it does not exist. But the 4831 ** the reason the mutex does not exist is because the build is not 4832 ** using mutexes. And we do not want the assert() containing the 4833 ** call to sqlite3_mutex_held() to fail, so a non-zero return is 4834 ** the appropriate thing to do. ^The sqlite3_mutex_notheld() 4835 ** interface should also return 1 when given a NULL pointer. 4836 */ 4837 #ifndef NDEBUG 4838 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*); 4839 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*); 4840 #endif 4841 4842 /* 4843 ** CAPI3REF: Mutex Types 4844 ** 4845 ** The [sqlite3_mutex_alloc()] interface takes a single argument 4846 ** which is one of these integer constants. 4847 ** 4848 ** The set of static mutexes may change from one SQLite release to the 4849 ** next. Applications that override the built-in mutex logic must be 4850 ** prepared to accommodate additional static mutexes. 4851 */ 4852 #define SQLITE_MUTEX_FAST 0 4853 #define SQLITE_MUTEX_RECURSIVE 1 4854 #define SQLITE_MUTEX_STATIC_MASTER 2 4855 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 4856 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 4857 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 4858 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 4859 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 4860 #define SQLITE_MUTEX_STATIC_LRU2 7 /* lru page list */ 4861 4862 /* 4863 ** CAPI3REF: Retrieve the mutex for a database connection 4864 ** 4865 ** ^This interface returns a pointer the [sqlite3_mutex] object that 4866 ** serializes access to the [database connection] given in the argument 4867 ** when the [threading mode] is Serialized. 4868 ** ^If the [threading mode] is Single-thread or Multi-thread then this 4869 ** routine returns a NULL pointer. 4870 */ 4871 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 4872 4873 /* 4874 ** CAPI3REF: Low-Level Control Of Database Files 4875 ** 4876 ** ^The [sqlite3_file_control()] interface makes a direct call to the 4877 ** xFileControl method for the [sqlite3_io_methods] object associated 4878 ** with a particular database identified by the second argument. ^The 4879 ** name of the database "main" for the main database or "temp" for the 4880 ** TEMP database, or the name that appears after the AS keyword for 4881 ** databases that are added using the [ATTACH] SQL command. 4882 ** ^A NULL pointer can be used in place of "main" to refer to the 4883 ** main database file. 4884 ** ^The third and fourth parameters to this routine 4885 ** are passed directly through to the second and third parameters of 4886 ** the xFileControl method. ^The return value of the xFileControl 4887 ** method becomes the return value of this routine. 4888 ** 4889 ** ^If the second parameter (zDbName) does not match the name of any 4890 ** open database file, then SQLITE_ERROR is returned. ^This error 4891 ** code is not remembered and will not be recalled by [sqlite3_errcode()] 4892 ** or [sqlite3_errmsg()]. The underlying xFileControl method might 4893 ** also return SQLITE_ERROR. There is no way to distinguish between 4894 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying 4895 ** xFileControl method. 4896 ** 4897 ** See also: [SQLITE_FCNTL_LOCKSTATE] 4898 */ 4899 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 4900 4901 /* 4902 ** CAPI3REF: Testing Interface 4903 ** 4904 ** ^The sqlite3_test_control() interface is used to read out internal 4905 ** state of SQLite and to inject faults into SQLite for testing 4906 ** purposes. ^The first parameter is an operation code that determines 4907 ** the number, meaning, and operation of all subsequent parameters. 4908 ** 4909 ** This interface is not for use by applications. It exists solely 4910 ** for verifying the correct operation of the SQLite library. Depending 4911 ** on how the SQLite library is compiled, this interface might not exist. 4912 ** 4913 ** The details of the operation codes, their meanings, the parameters 4914 ** they take, and what they do are all subject to change without notice. 4915 ** Unlike most of the SQLite API, this function is not guaranteed to 4916 ** operate consistently from one release to the next. 4917 */ 4918 SQLITE_API int sqlite3_test_control(int op, ...); 4919 4920 /* 4921 ** CAPI3REF: Testing Interface Operation Codes 4922 ** 4923 ** These constants are the valid operation code parameters used 4924 ** as the first argument to [sqlite3_test_control()]. 4925 ** 4926 ** These parameters and their meanings are subject to change 4927 ** without notice. These values are for testing purposes only. 4928 ** Applications should not use any of these parameters or the 4929 ** [sqlite3_test_control()] interface. 4930 */ 4931 #define SQLITE_TESTCTRL_FIRST 5 4932 #define SQLITE_TESTCTRL_PRNG_SAVE 5 4933 #define SQLITE_TESTCTRL_PRNG_RESTORE 6 4934 #define SQLITE_TESTCTRL_PRNG_RESET 7 4935 #define SQLITE_TESTCTRL_BITVEC_TEST 8 4936 #define SQLITE_TESTCTRL_FAULT_INSTALL 9 4937 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 4938 #define SQLITE_TESTCTRL_PENDING_BYTE 11 4939 #define SQLITE_TESTCTRL_ASSERT 12 4940 #define SQLITE_TESTCTRL_ALWAYS 13 4941 #define SQLITE_TESTCTRL_RESERVE 14 4942 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15 4943 #define SQLITE_TESTCTRL_ISKEYWORD 16 4944 #define SQLITE_TESTCTRL_LAST 16 4945 4946 /* 4947 ** CAPI3REF: SQLite Runtime Status 4948 ** EXPERIMENTAL 4949 ** 4950 ** ^This interface is used to retrieve runtime status information 4951 ** about the preformance of SQLite, and optionally to reset various 4952 ** highwater marks. ^The first argument is an integer code for 4953 ** the specific parameter to measure. ^(Recognized integer codes 4954 ** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].)^ 4955 ** ^The current value of the parameter is returned into *pCurrent. 4956 ** ^The highest recorded value is returned in *pHighwater. ^If the 4957 ** resetFlag is true, then the highest record value is reset after 4958 ** *pHighwater is written. ^(Some parameters do not record the highest 4959 ** value. For those parameters 4960 ** nothing is written into *pHighwater and the resetFlag is ignored.)^ 4961 ** ^(Other parameters record only the highwater mark and not the current 4962 ** value. For these latter parameters nothing is written into *pCurrent.)^ 4963 ** 4964 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 4965 ** non-zero [error code] on failure. 4966 ** 4967 ** This routine is threadsafe but is not atomic. This routine can be 4968 ** called while other threads are running the same or different SQLite 4969 ** interfaces. However the values returned in *pCurrent and 4970 ** *pHighwater reflect the status of SQLite at different points in time 4971 ** and it is possible that another thread might change the parameter 4972 ** in between the times when *pCurrent and *pHighwater are written. 4973 ** 4974 ** See also: [sqlite3_db_status()] 4975 */ 4976 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 4977 4978 4979 /* 4980 ** CAPI3REF: Status Parameters 4981 ** EXPERIMENTAL 4982 ** 4983 ** These integer constants designate various run-time status parameters 4984 ** that can be returned by [sqlite3_status()]. 4985 ** 4986 ** <dl> 4987 ** ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 4988 ** <dd>This parameter is the current amount of memory checked out 4989 ** using [sqlite3_malloc()], either directly or indirectly. The 4990 ** figure includes calls made to [sqlite3_malloc()] by the application 4991 ** and internal memory usage by the SQLite library. Scratch memory 4992 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 4993 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 4994 ** this parameter. The amount returned is the sum of the allocation 4995 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 4996 ** 4997 ** ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 4998 ** <dd>This parameter records the largest memory allocation request 4999 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 5000 ** internal equivalents). Only the value returned in the 5001 ** *pHighwater parameter to [sqlite3_status()] is of interest. 5002 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 5003 ** 5004 ** ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 5005 ** <dd>This parameter returns the number of pages used out of the 5006 ** [pagecache memory allocator] that was configured using 5007 ** [SQLITE_CONFIG_PAGECACHE]. The 5008 ** value returned is in pages, not in bytes.</dd>)^ 5009 ** 5010 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5011 ** <dd>This parameter returns the number of bytes of page cache 5012 ** allocation which could not be statisfied by the [SQLITE_CONFIG_PAGECACHE] 5013 ** buffer and where forced to overflow to [sqlite3_malloc()]. The 5014 ** returned value includes allocations that overflowed because they 5015 ** where too large (they were larger than the "sz" parameter to 5016 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 5017 ** no space was left in the page cache.</dd>)^ 5018 ** 5019 ** ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 5020 ** <dd>This parameter records the largest memory allocation request 5021 ** handed to [pagecache memory allocator]. Only the value returned in the 5022 ** *pHighwater parameter to [sqlite3_status()] is of interest. 5023 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 5024 ** 5025 ** ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 5026 ** <dd>This parameter returns the number of allocations used out of the 5027 ** [scratch memory allocator] configured using 5028 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5029 ** in bytes. Since a single thread may only have one scratch allocation 5030 ** outstanding at time, this parameter also reports the number of threads 5031 ** using scratch memory at the same time.</dd>)^ 5032 ** 5033 ** ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5034 ** <dd>This parameter returns the number of bytes of scratch memory 5035 ** allocation which could not be statisfied by the [SQLITE_CONFIG_SCRATCH] 5036 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5037 ** returned include overflows because the requested allocation was too 5038 ** larger (that is, because the requested allocation was larger than the 5039 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5040 ** slots were available. 5041 ** </dd>)^ 5042 ** 5043 ** ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5044 ** <dd>This parameter records the largest memory allocation request 5045 ** handed to [scratch memory allocator]. Only the value returned in the 5046 ** *pHighwater parameter to [sqlite3_status()] is of interest. 5047 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 5048 ** 5049 ** ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 5050 ** <dd>This parameter records the deepest parser stack. It is only 5051 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 5052 ** </dl> 5053 ** 5054 ** New status parameters may be added from time to time. 5055 */ 5056 #define SQLITE_STATUS_MEMORY_USED 0 5057 #define SQLITE_STATUS_PAGECACHE_USED 1 5058 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5059 #define SQLITE_STATUS_SCRATCH_USED 3 5060 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5061 #define SQLITE_STATUS_MALLOC_SIZE 5 5062 #define SQLITE_STATUS_PARSER_STACK 6 5063 #define SQLITE_STATUS_PAGECACHE_SIZE 7 5064 #define SQLITE_STATUS_SCRATCH_SIZE 8 5065 5066 /* 5067 ** CAPI3REF: Database Connection Status 5068 ** EXPERIMENTAL 5069 ** 5070 ** ^This interface is used to retrieve runtime status information 5071 ** about a single [database connection]. ^The first argument is the 5072 ** database connection object to be interrogated. ^The second argument 5073 ** is the parameter to interrogate. ^Currently, the only allowed value 5074 ** for the second parameter is [SQLITE_DBSTATUS_LOOKASIDE_USED]. 5075 ** Additional options will likely appear in future releases of SQLite. 5076 ** 5077 ** ^The current value of the requested parameter is written into *pCur 5078 ** and the highest instantaneous value is written into *pHiwtr. ^If 5079 ** the resetFlg is true, then the highest instantaneous value is 5080 ** reset back down to the current value. 5081 ** 5082 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5083 */ 5084 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5085 5086 /* 5087 ** CAPI3REF: Status Parameters for database connections 5088 ** EXPERIMENTAL 5089 ** 5090 ** These constants are the available integer "verbs" that can be passed as 5091 ** the second argument to the [sqlite3_db_status()] interface. 5092 ** 5093 ** New verbs may be added in future releases of SQLite. Existing verbs 5094 ** might be discontinued. Applications should check the return code from 5095 ** [sqlite3_db_status()] to make sure that the call worked. 5096 ** The [sqlite3_db_status()] interface will return a non-zero error code 5097 ** if a discontinued or unsupported verb is invoked. 5098 ** 5099 ** <dl> 5100 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5101 ** <dd>This parameter returns the number of lookaside memory slots currently 5102 ** checked out.</dd>)^ 5103 ** </dl> 5104 */ 5105 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0 5106 5107 5108 /* 5109 ** CAPI3REF: Prepared Statement Status 5110 ** EXPERIMENTAL 5111 ** 5112 ** ^(Each prepared statement maintains various 5113 ** [SQLITE_STMTSTATUS_SORT | counters] that measure the number 5114 ** of times it has performed specific operations.)^ These counters can 5115 ** be used to monitor the performance characteristics of the prepared 5116 ** statements. For example, if the number of table steps greatly exceeds 5117 ** the number of table searches or result rows, that would tend to indicate 5118 ** that the prepared statement is using a full table scan rather than 5119 ** an index. 5120 ** 5121 ** ^(This interface is used to retrieve and reset counter values from 5122 ** a [prepared statement]. The first argument is the prepared statement 5123 ** object to be interrogated. The second argument 5124 ** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter] 5125 ** to be interrogated.)^ 5126 ** ^The current value of the requested counter is returned. 5127 ** ^If the resetFlg is true, then the counter is reset to zero after this 5128 ** interface call returns. 5129 ** 5130 ** See also: [sqlite3_status()] and [sqlite3_db_status()]. 5131 */ 5132 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 5133 5134 /* 5135 ** CAPI3REF: Status Parameters for prepared statements 5136 ** EXPERIMENTAL 5137 ** 5138 ** These preprocessor macros define integer codes that name counter 5139 ** values associated with the [sqlite3_stmt_status()] interface. 5140 ** The meanings of the various counters are as follows: 5141 ** 5142 ** <dl> 5143 ** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 5144 ** <dd>^This is the number of times that SQLite has stepped forward in 5145 ** a table as part of a full table scan. Large numbers for this counter 5146 ** may indicate opportunities for performance improvement through 5147 ** careful use of indices.</dd> 5148 ** 5149 ** <dt>SQLITE_STMTSTATUS_SORT</dt> 5150 ** <dd>^This is the number of sort operations that have occurred. 5151 ** A non-zero value in this counter may indicate an opportunity to 5152 ** improvement performance through careful use of indices.</dd> 5153 ** 5154 ** </dl> 5155 */ 5156 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 5157 #define SQLITE_STMTSTATUS_SORT 2 5158 5159 /* 5160 ** CAPI3REF: Custom Page Cache Object 5161 ** EXPERIMENTAL 5162 ** 5163 ** The sqlite3_pcache type is opaque. It is implemented by 5164 ** the pluggable module. The SQLite core has no knowledge of 5165 ** its size or internal structure and never deals with the 5166 ** sqlite3_pcache object except by holding and passing pointers 5167 ** to the object. 5168 ** 5169 ** See [sqlite3_pcache_methods] for additional information. 5170 */ 5171 typedef struct sqlite3_pcache sqlite3_pcache; 5172 5173 /* 5174 ** CAPI3REF: Application Defined Page Cache. 5175 ** KEYWORDS: {page cache} 5176 ** EXPERIMENTAL 5177 ** 5178 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can 5179 ** register an alternative page cache implementation by passing in an 5180 ** instance of the sqlite3_pcache_methods structure.)^ The majority of the 5181 ** heap memory used by SQLite is used by the page cache to cache data read 5182 ** from, or ready to be written to, the database file. By implementing a 5183 ** custom page cache using this API, an application can control more 5184 ** precisely the amount of memory consumed by SQLite, the way in which 5185 ** that memory is allocated and released, and the policies used to 5186 ** determine exactly which parts of a database file are cached and for 5187 ** how long. 5188 ** 5189 ** ^(The contents of the sqlite3_pcache_methods structure are copied to an 5190 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence 5191 ** the application may discard the parameter after the call to 5192 ** [sqlite3_config()] returns.)^ 5193 ** 5194 ** ^The xInit() method is called once for each call to [sqlite3_initialize()] 5195 ** (usually only once during the lifetime of the process). ^(The xInit() 5196 ** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^ 5197 ** ^The xInit() method can set up up global structures and/or any mutexes 5198 ** required by the custom page cache implementation. 5199 ** 5200 ** ^The xShutdown() method is called from within [sqlite3_shutdown()], 5201 ** if the application invokes this API. It can be used to clean up 5202 ** any outstanding resources before process shutdown, if required. 5203 ** 5204 ** ^SQLite holds a [SQLITE_MUTEX_RECURSIVE] mutex when it invokes 5205 ** the xInit method, so the xInit method need not be threadsafe. ^The 5206 ** xShutdown method is only called from [sqlite3_shutdown()] so it does 5207 ** not need to be threadsafe either. All other methods must be threadsafe 5208 ** in multithreaded applications. 5209 ** 5210 ** ^SQLite will never invoke xInit() more than once without an intervening 5211 ** call to xShutdown(). 5212 ** 5213 ** ^The xCreate() method is used to construct a new cache instance. SQLite 5214 ** will typically create one cache instance for each open database file, 5215 ** though this is not guaranteed. ^The 5216 ** first parameter, szPage, is the size in bytes of the pages that must 5217 ** be allocated by the cache. ^szPage will not be a power of two. ^szPage 5218 ** will the page size of the database file that is to be cached plus an 5219 ** increment (here called "R") of about 100 or 200. ^SQLite will use the 5220 ** extra R bytes on each page to store metadata about the underlying 5221 ** database page on disk. The value of R depends 5222 ** on the SQLite version, the target platform, and how SQLite was compiled. 5223 ** ^R is constant for a particular build of SQLite. ^The second argument to 5224 ** xCreate(), bPurgeable, is true if the cache being created will 5225 ** be used to cache database pages of a file stored on disk, or 5226 ** false if it is used for an in-memory database. ^The cache implementation 5227 ** does not have to do anything special based with the value of bPurgeable; 5228 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 5229 ** never invoke xUnpin() except to deliberately delete a page. 5230 ** ^In other words, a cache created with bPurgeable set to false will 5231 ** never contain any unpinned pages. 5232 ** 5233 ** ^(The xCachesize() method may be called at any time by SQLite to set the 5234 ** suggested maximum cache-size (number of pages stored by) the cache 5235 ** instance passed as the first argument. This is the value configured using 5236 ** the SQLite "[PRAGMA cache_size]" command.)^ ^As with the bPurgeable 5237 ** parameter, the implementation is not required to do anything with this 5238 ** value; it is advisory only. 5239 ** 5240 ** ^The xPagecount() method should return the number of pages currently 5241 ** stored in the cache. 5242 ** 5243 ** ^The xFetch() method is used to fetch a page and return a pointer to it. 5244 ** ^A 'page', in this context, is a buffer of szPage bytes aligned at an 5245 ** 8-byte boundary. ^The page to be fetched is determined by the key. ^The 5246 ** mimimum key value is 1. After it has been retrieved using xFetch, the page 5247 ** is considered to be "pinned". 5248 ** 5249 ** ^If the requested page is already in the page cache, then the page cache 5250 ** implementation must return a pointer to the page buffer with its content 5251 ** intact. ^(If the requested page is not already in the cache, then the 5252 ** behavior of the cache implementation is determined by the value of the 5253 ** createFlag parameter passed to xFetch, according to the following table: 5254 ** 5255 ** <table border=1 width=85% align=center> 5256 ** <tr><th> createFlag <th> Behaviour when page is not already in cache 5257 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 5258 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 5259 ** Otherwise return NULL. 5260 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 5261 ** NULL if allocating a new page is effectively impossible. 5262 ** </table>)^ 5263 ** 5264 ** SQLite will normally invoke xFetch() with a createFlag of 0 or 1. If 5265 ** a call to xFetch() with createFlag==1 returns NULL, then SQLite will 5266 ** attempt to unpin one or more cache pages by spilling the content of 5267 ** pinned pages to disk and synching the operating system disk cache. After 5268 ** attempting to unpin pages, the xFetch() method will be invoked again with 5269 ** a createFlag of 2. 5270 ** 5271 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 5272 ** as its second argument. ^(If the third parameter, discard, is non-zero, 5273 ** then the page should be evicted from the cache. In this case SQLite 5274 ** assumes that the next time the page is retrieved from the cache using 5275 ** the xFetch() method, it will be zeroed.)^ ^If the discard parameter is 5276 ** zero, then the page is considered to be unpinned. ^The cache implementation 5277 ** may choose to evict unpinned pages at any time. 5278 ** 5279 ** ^(The cache is not required to perform any reference counting. A single 5280 ** call to xUnpin() unpins the page regardless of the number of prior calls 5281 ** to xFetch().)^ 5282 ** 5283 ** ^The xRekey() method is used to change the key value associated with the 5284 ** page passed as the second argument from oldKey to newKey. ^If the cache 5285 ** previously contains an entry associated with newKey, it should be 5286 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not 5287 ** to be pinned. 5288 ** 5289 ** ^When SQLite calls the xTruncate() method, the cache must discard all 5290 ** existing cache entries with page numbers (keys) greater than or equal 5291 ** to the value of the iLimit parameter passed to xTruncate(). ^If any 5292 ** of these pages are pinned, they are implicitly unpinned, meaning that 5293 ** they can be safely discarded. 5294 ** 5295 ** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 5296 ** All resources associated with the specified cache should be freed. ^After 5297 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 5298 ** handle invalid, and will not use it with any other sqlite3_pcache_methods 5299 ** functions. 5300 */ 5301 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 5302 struct sqlite3_pcache_methods { 5303 void *pArg; 5304 int (*xInit)(void*); 5305 void (*xShutdown)(void*); 5306 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 5307 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 5308 int (*xPagecount)(sqlite3_pcache*); 5309 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 5310 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 5311 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 5312 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 5313 void (*xDestroy)(sqlite3_pcache*); 5314 }; 5315 5316 /* 5317 ** CAPI3REF: Online Backup Object 5318 ** EXPERIMENTAL 5319 ** 5320 ** The sqlite3_backup object records state information about an ongoing 5321 ** online backup operation. ^The sqlite3_backup object is created by 5322 ** a call to [sqlite3_backup_init()] and is destroyed by a call to 5323 ** [sqlite3_backup_finish()]. 5324 ** 5325 ** See Also: [Using the SQLite Online Backup API] 5326 */ 5327 typedef struct sqlite3_backup sqlite3_backup; 5328 5329 /* 5330 ** CAPI3REF: Online Backup API. 5331 ** EXPERIMENTAL 5332 ** 5333 ** The backup API copies the content of one database into another. 5334 ** It is useful either for creating backups of databases or 5335 ** for copying in-memory databases to or from persistent files. 5336 ** 5337 ** See Also: [Using the SQLite Online Backup API] 5338 ** 5339 ** ^Exclusive access is required to the destination database for the 5340 ** duration of the operation. ^However the source database is only 5341 ** read-locked while it is actually being read; it is not locked 5342 ** continuously for the entire backup operation. ^Thus, the backup may be 5343 ** performed on a live source database without preventing other users from 5344 ** reading or writing to the source database while the backup is underway. 5345 ** 5346 ** ^(To perform a backup operation: 5347 ** <ol> 5348 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the 5349 ** backup, 5350 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 5351 ** the data between the two databases, and finally 5352 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources 5353 ** associated with the backup operation. 5354 ** </ol>)^ 5355 ** There should be exactly one call to sqlite3_backup_finish() for each 5356 ** successful call to sqlite3_backup_init(). 5357 ** 5358 ** <b>sqlite3_backup_init()</b> 5359 ** 5360 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 5361 ** [database connection] associated with the destination database 5362 ** and the database name, respectively. 5363 ** ^The database name is "main" for the main database, "temp" for the 5364 ** temporary database, or the name specified after the AS keyword in 5365 ** an [ATTACH] statement for an attached database. 5366 ** ^The S and M arguments passed to 5367 ** sqlite3_backup_init(D,N,S,M) identify the [database connection] 5368 ** and database name of the source database, respectively. 5369 ** ^The source and destination [database connections] (parameters S and D) 5370 ** must be different or else sqlite3_backup_init(D,N,S,M) will file with 5371 ** an error. 5372 ** 5373 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 5374 ** returned and an error code and error message are store3d in the 5375 ** destination [database connection] D. 5376 ** ^The error code and message for the failed call to sqlite3_backup_init() 5377 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 5378 ** [sqlite3_errmsg16()] functions. 5379 ** ^A successful call to sqlite3_backup_init() returns a pointer to an 5380 ** [sqlite3_backup] object. 5381 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 5382 ** sqlite3_backup_finish() functions to perform the specified backup 5383 ** operation. 5384 ** 5385 ** <b>sqlite3_backup_step()</b> 5386 ** 5387 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 5388 ** the source and destination databases specified by [sqlite3_backup] object B. 5389 ** ^If N is negative, all remaining source pages are copied. 5390 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 5391 ** are still more pages to be copied, then the function resturns [SQLITE_OK]. 5392 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 5393 ** from source to destination, then it returns [SQLITE_DONE]. 5394 ** ^If an error occurs while running sqlite3_backup_step(B,N), 5395 ** then an [error code] is returned. ^As well as [SQLITE_OK] and 5396 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 5397 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 5398 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 5399 ** 5400 ** ^The sqlite3_backup_step() might return [SQLITE_READONLY] if the destination 5401 ** database was opened read-only or if 5402 ** the destination is an in-memory database with a different page size 5403 ** from the source database. 5404 ** 5405 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 5406 ** the [sqlite3_busy_handler | busy-handler function] 5407 ** is invoked (if one is specified). ^If the 5408 ** busy-handler returns non-zero before the lock is available, then 5409 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 5410 ** sqlite3_backup_step() can be retried later. ^If the source 5411 ** [database connection] 5412 ** is being used to write to the source database when sqlite3_backup_step() 5413 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 5414 ** case the call to sqlite3_backup_step() can be retried later on. ^(If 5415 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 5416 ** [SQLITE_READONLY] is returned, then 5417 ** there is no point in retrying the call to sqlite3_backup_step(). These 5418 ** errors are considered fatal.)^ The application must accept 5419 ** that the backup operation has failed and pass the backup operation handle 5420 ** to the sqlite3_backup_finish() to release associated resources. 5421 ** 5422 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock 5423 ** on the destination file. ^The exclusive lock is not released until either 5424 ** sqlite3_backup_finish() is called or the backup operation is complete 5425 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 5426 ** sqlite3_backup_step() obtains a [shared lock] on the source database that 5427 ** lasts for the duration of the sqlite3_backup_step() call. 5428 ** ^Because the source database is not locked between calls to 5429 ** sqlite3_backup_step(), the source database may be modified mid-way 5430 ** through the backup process. ^If the source database is modified by an 5431 ** external process or via a database connection other than the one being 5432 ** used by the backup operation, then the backup will be automatically 5433 ** restarted by the next call to sqlite3_backup_step(). ^If the source 5434 ** database is modified by the using the same database connection as is used 5435 ** by the backup operation, then the backup database is automatically 5436 ** updated at the same time. 5437 ** 5438 ** <b>sqlite3_backup_finish()</b> 5439 ** 5440 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 5441 ** application wishes to abandon the backup operation, the application 5442 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 5443 ** ^The sqlite3_backup_finish() interfaces releases all 5444 ** resources associated with the [sqlite3_backup] object. 5445 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 5446 ** active write-transaction on the destination database is rolled back. 5447 ** The [sqlite3_backup] object is invalid 5448 ** and may not be used following a call to sqlite3_backup_finish(). 5449 ** 5450 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 5451 ** sqlite3_backup_step() errors occurred, regardless or whether or not 5452 ** sqlite3_backup_step() completed. 5453 ** ^If an out-of-memory condition or IO error occurred during any prior 5454 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 5455 ** sqlite3_backup_finish() returns the corresponding [error code]. 5456 ** 5457 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 5458 ** is not a permanent error and does not affect the return value of 5459 ** sqlite3_backup_finish(). 5460 ** 5461 ** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b> 5462 ** 5463 ** ^Each call to sqlite3_backup_step() sets two values inside 5464 ** the [sqlite3_backup] object: the number of pages still to be backed 5465 ** up and the total number of pages in the source databae file. 5466 ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 5467 ** retrieve these two values, respectively. 5468 ** 5469 ** ^The values returned by these functions are only updated by 5470 ** sqlite3_backup_step(). ^If the source database is modified during a backup 5471 ** operation, then the values are not updated to account for any extra 5472 ** pages that need to be updated or the size of the source database file 5473 ** changing. 5474 ** 5475 ** <b>Concurrent Usage of Database Handles</b> 5476 ** 5477 ** ^The source [database connection] may be used by the application for other 5478 ** purposes while a backup operation is underway or being initialized. 5479 ** ^If SQLite is compiled and configured to support threadsafe database 5480 ** connections, then the source database connection may be used concurrently 5481 ** from within other threads. 5482 ** 5483 ** However, the application must guarantee that the destination 5484 ** [database connection] is not passed to any other API (by any thread) after 5485 ** sqlite3_backup_init() is called and before the corresponding call to 5486 ** sqlite3_backup_finish(). SQLite does not currently check to see 5487 ** if the application incorrectly accesses the destination [database connection] 5488 ** and so no error code is reported, but the operations may malfunction 5489 ** nevertheless. Use of the destination database connection while a 5490 ** backup is in progress might also also cause a mutex deadlock. 5491 ** 5492 ** If running in [shared cache mode], the application must 5493 ** guarantee that the shared cache used by the destination database 5494 ** is not accessed while the backup is running. In practice this means 5495 ** that the application must guarantee that the disk file being 5496 ** backed up to is not accessed by any connection within the process, 5497 ** not just the specific connection that was passed to sqlite3_backup_init(). 5498 ** 5499 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple 5500 ** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 5501 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 5502 ** APIs are not strictly speaking threadsafe. If they are invoked at the 5503 ** same time as another thread is invoking sqlite3_backup_step() it is 5504 ** possible that they return invalid values. 5505 */ 5506 SQLITE_API sqlite3_backup *sqlite3_backup_init( 5507 sqlite3 *pDest, /* Destination database handle */ 5508 const char *zDestName, /* Destination database name */ 5509 sqlite3 *pSource, /* Source database handle */ 5510 const char *zSourceName /* Source database name */ 5511 ); 5512 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage); 5513 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p); 5514 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p); 5515 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p); 5516 5517 /* 5518 ** CAPI3REF: Unlock Notification 5519 ** EXPERIMENTAL 5520 ** 5521 ** ^When running in shared-cache mode, a database operation may fail with 5522 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 5523 ** individual tables within the shared-cache cannot be obtained. See 5524 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 5525 ** ^This API may be used to register a callback that SQLite will invoke 5526 ** when the connection currently holding the required lock relinquishes it. 5527 ** ^This API is only available if the library was compiled with the 5528 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 5529 ** 5530 ** See Also: [Using the SQLite Unlock Notification Feature]. 5531 ** 5532 ** ^Shared-cache locks are released when a database connection concludes 5533 ** its current transaction, either by committing it or rolling it back. 5534 ** 5535 ** ^When a connection (known as the blocked connection) fails to obtain a 5536 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 5537 ** identity of the database connection (the blocking connection) that 5538 ** has locked the required resource is stored internally. ^After an 5539 ** application receives an SQLITE_LOCKED error, it may call the 5540 ** sqlite3_unlock_notify() method with the blocked connection handle as 5541 ** the first argument to register for a callback that will be invoked 5542 ** when the blocking connections current transaction is concluded. ^The 5543 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 5544 ** call that concludes the blocking connections transaction. 5545 ** 5546 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 5547 ** there is a chance that the blocking connection will have already 5548 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 5549 ** If this happens, then the specified callback is invoked immediately, 5550 ** from within the call to sqlite3_unlock_notify().)^ 5551 ** 5552 ** ^If the blocked connection is attempting to obtain a write-lock on a 5553 ** shared-cache table, and more than one other connection currently holds 5554 ** a read-lock on the same table, then SQLite arbitrarily selects one of 5555 ** the other connections to use as the blocking connection. 5556 ** 5557 ** ^(There may be at most one unlock-notify callback registered by a 5558 ** blocked connection. If sqlite3_unlock_notify() is called when the 5559 ** blocked connection already has a registered unlock-notify callback, 5560 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 5561 ** called with a NULL pointer as its second argument, then any existing 5562 ** unlock-notify callback is cancelled. ^The blocked connections 5563 ** unlock-notify callback may also be canceled by closing the blocked 5564 ** connection using [sqlite3_close()]. 5565 ** 5566 ** The unlock-notify callback is not reentrant. If an application invokes 5567 ** any sqlite3_xxx API functions from within an unlock-notify callback, a 5568 ** crash or deadlock may be the result. 5569 ** 5570 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 5571 ** returns SQLITE_OK. 5572 ** 5573 ** <b>Callback Invocation Details</b> 5574 ** 5575 ** When an unlock-notify callback is registered, the application provides a 5576 ** single void* pointer that is passed to the callback when it is invoked. 5577 ** However, the signature of the callback function allows SQLite to pass 5578 ** it an array of void* context pointers. The first argument passed to 5579 ** an unlock-notify callback is a pointer to an array of void* pointers, 5580 ** and the second is the number of entries in the array. 5581 ** 5582 ** When a blocking connections transaction is concluded, there may be 5583 ** more than one blocked connection that has registered for an unlock-notify 5584 ** callback. ^If two or more such blocked connections have specified the 5585 ** same callback function, then instead of invoking the callback function 5586 ** multiple times, it is invoked once with the set of void* context pointers 5587 ** specified by the blocked connections bundled together into an array. 5588 ** This gives the application an opportunity to prioritize any actions 5589 ** related to the set of unblocked database connections. 5590 ** 5591 ** <b>Deadlock Detection</b> 5592 ** 5593 ** Assuming that after registering for an unlock-notify callback a 5594 ** database waits for the callback to be issued before taking any further 5595 ** action (a reasonable assumption), then using this API may cause the 5596 ** application to deadlock. For example, if connection X is waiting for 5597 ** connection Y's transaction to be concluded, and similarly connection 5598 ** Y is waiting on connection X's transaction, then neither connection 5599 ** will proceed and the system may remain deadlocked indefinitely. 5600 ** 5601 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 5602 ** detection. ^If a given call to sqlite3_unlock_notify() would put the 5603 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no 5604 ** unlock-notify callback is registered. The system is said to be in 5605 ** a deadlocked state if connection A has registered for an unlock-notify 5606 ** callback on the conclusion of connection B's transaction, and connection 5607 ** B has itself registered for an unlock-notify callback when connection 5608 ** A's transaction is concluded. ^Indirect deadlock is also detected, so 5609 ** the system is also considered to be deadlocked if connection B has 5610 ** registered for an unlock-notify callback on the conclusion of connection 5611 ** C's transaction, where connection C is waiting on connection A. ^Any 5612 ** number of levels of indirection are allowed. 5613 ** 5614 ** <b>The "DROP TABLE" Exception</b> 5615 ** 5616 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 5617 ** always appropriate to call sqlite3_unlock_notify(). There is however, 5618 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 5619 ** SQLite checks if there are any currently executing SELECT statements 5620 ** that belong to the same connection. If there are, SQLITE_LOCKED is 5621 ** returned. In this case there is no "blocking connection", so invoking 5622 ** sqlite3_unlock_notify() results in the unlock-notify callback being 5623 ** invoked immediately. If the application then re-attempts the "DROP TABLE" 5624 ** or "DROP INDEX" query, an infinite loop might be the result. 5625 ** 5626 ** One way around this problem is to check the extended error code returned 5627 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the 5628 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 5629 ** the special "DROP TABLE/INDEX" case, the extended error code is just 5630 ** SQLITE_LOCKED.)^ 5631 */ 5632 SQLITE_API int sqlite3_unlock_notify( 5633 sqlite3 *pBlocked, /* Waiting connection */ 5634 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 5635 void *pNotifyArg /* Argument to pass to xNotify */ 5636 ); 5637 5638 5639 /* 5640 ** CAPI3REF: String Comparison 5641 ** EXPERIMENTAL 5642 ** 5643 ** ^The [sqlite3_strnicmp()] API allows applications and extensions to 5644 ** compare the contents of two buffers containing UTF-8 strings in a 5645 ** case-indendent fashion, using the same definition of case independence 5646 ** that SQLite uses internally when comparing identifiers. 5647 */ 5648 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int); 5649 5650 /* 5651 ** CAPI3REF: Error Logging Interface 5652 ** EXPERIMENTAL 5653 ** 5654 ** ^The [sqlite3_log()] interface writes a message into the error log 5655 ** established by the [SQLITE_CONFIG_ERRORLOG] option to [sqlite3_config()]. 5656 ** 5657 ** The sqlite3_log() interface is intended for use by extensions such as 5658 ** virtual tables, collating functions, and SQL functions. While there is 5659 ** nothing to prevent an application from calling sqlite3_log(), doing so 5660 ** is considered bad form. 5661 ** 5662 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine 5663 ** will not use dynamically allocated memory. The log message is stored in 5664 ** a fixed-length buffer on the stack. If the log message is longer than 5665 ** a few hundred characters, it will be truncated to the length of the 5666 ** buffer. 5667 */ 5668 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...); 5669 5670 // Begin Android add 5671 /* 5672 ** Android additional API. 5673 ** 5674 ** This function changes the default behavior of BEGIN to IMMEDIATE if called 5675 ** with immediate=1. 5676 ** Calling with immediate=0 will revert to DEFERRED. 5677 */ 5678 int sqlite3_set_transaction_default_immediate(sqlite3*, int immediate); 5679 // End Android add 5680 /* 5681 ** Undo the hack that converts floating point types to integer for 5682 ** builds on processors without floating point support. 5683 */ 5684 #ifdef SQLITE_OMIT_FLOATING_POINT 5685 # undef double 5686 #endif 5687 5688 #ifdef __cplusplus 5689 } /* End of the 'extern "C"' block */ 5690 #endif 5691 #endif 5692 5693
