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 to make minor changes if 22 ** 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 ** @(#) $Id: sqlite.h.in,v 1.436 2009/03/20 13:15:30 drh Exp $ 34 */ 35 #ifndef _SQLITE3_H_ 36 #define _SQLITE3_H_ 37 #include <stdarg.h> /* Needed for the definition of va_list */ 38 39 /* 40 ** Make sure we can call this stuff from C++. 41 */ 42 #ifdef __cplusplus 43 extern "C" { 44 #endif 45 46 47 /* 48 ** Add the ability to override 'extern' 49 */ 50 #ifndef SQLITE_EXTERN 51 # define SQLITE_EXTERN extern 52 #endif 53 54 /* 55 ** These no-op macros are used in front of interfaces to mark those 56 ** interfaces as either deprecated or experimental. New applications 57 ** should not use deprecated intrfaces - they are support for backwards 58 ** compatibility only. Application writers should be aware that 59 ** experimental interfaces are subject to change in point releases. 60 ** 61 ** These macros used to resolve to various kinds of compiler magic that 62 ** would generate warning messages when they were used. But that 63 ** compiler magic ended up generating such a flurry of bug reports 64 ** that we have taken it all out and gone back to using simple 65 ** noop macros. 66 */ 67 #define SQLITE_DEPRECATED 68 #define SQLITE_EXPERIMENTAL 69 70 /* 71 ** Ensure these symbols were not defined by some previous header file. 72 */ 73 #ifdef SQLITE_VERSION 74 # undef SQLITE_VERSION 75 #endif 76 #ifdef SQLITE_VERSION_NUMBER 77 # undef SQLITE_VERSION_NUMBER 78 #endif 79 80 /* 81 ** CAPI3REF: Compile-Time Library Version Numbers {H10010} <S60100> 82 ** 83 ** The SQLITE_VERSION and SQLITE_VERSION_NUMBER #defines in 84 ** the sqlite3.h file specify the version of SQLite with which 85 ** that header file is associated. 86 ** 87 ** The "version" of SQLite is a string of the form "X.Y.Z". 88 ** The phrase "alpha" or "beta" might be appended after the Z. 89 ** The X value is major version number always 3 in SQLite3. 90 ** The X value only changes when backwards compatibility is 91 ** broken and we intend to never break backwards compatibility. 92 ** The Y value is the minor version number and only changes when 93 ** there are major feature enhancements that are forwards compatible 94 ** but not backwards compatible. 95 ** The Z value is the release number and is incremented with 96 ** each release but resets back to 0 whenever Y is incremented. 97 ** 98 ** See also: [sqlite3_libversion()] and [sqlite3_libversion_number()]. 99 ** 100 ** Requirements: [H10011] [H10014] 101 */ 102 #define SQLITE_VERSION "3.6.12" 103 #define SQLITE_VERSION_NUMBER 3006012 104 105 /* 106 ** CAPI3REF: Run-Time Library Version Numbers {H10020} <S60100> 107 ** KEYWORDS: sqlite3_version 108 ** 109 ** These features provide the same information as the [SQLITE_VERSION] 110 ** and [SQLITE_VERSION_NUMBER] #defines in the header, but are associated 111 ** with the library instead of the header file. Cautious programmers might 112 ** include a check in their application to verify that 113 ** sqlite3_libversion_number() always returns the value 114 ** [SQLITE_VERSION_NUMBER]. 115 ** 116 ** The sqlite3_libversion() function returns the same information as is 117 ** in the sqlite3_version[] string constant. The function is provided 118 ** for use in DLLs since DLL users usually do not have direct access to string 119 ** constants within the DLL. 120 ** 121 ** Requirements: [H10021] [H10022] [H10023] 122 */ 123 SQLITE_EXTERN const char sqlite3_version[]; 124 const char *sqlite3_libversion(void); 125 int sqlite3_libversion_number(void); 126 127 /* 128 ** CAPI3REF: Test To See If The Library Is Threadsafe {H10100} <S60100> 129 ** 130 ** SQLite can be compiled with or without mutexes. When 131 ** the [SQLITE_THREADSAFE] C preprocessor macro 1 or 2, mutexes 132 ** are enabled and SQLite is threadsafe. When the 133 ** [SQLITE_THREADSAFE] macro is 0, 134 ** the mutexes are omitted. Without the mutexes, it is not safe 135 ** to use SQLite concurrently from more than one thread. 136 ** 137 ** Enabling mutexes incurs a measurable performance penalty. 138 ** So if speed is of utmost importance, it makes sense to disable 139 ** the mutexes. But for maximum safety, mutexes should be enabled. 140 ** The default behavior is for mutexes to be enabled. 141 ** 142 ** This interface can be used by a program to make sure that the 143 ** version of SQLite that it is linking against was compiled with 144 ** the desired setting of the [SQLITE_THREADSAFE] macro. 145 ** 146 ** This interface only reports on the compile-time mutex setting 147 ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 148 ** SQLITE_THREADSAFE=1 then mutexes are enabled by default but 149 ** can be fully or partially disabled using a call to [sqlite3_config()] 150 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 151 ** or [SQLITE_CONFIG_MUTEX]. The return value of this function shows 152 ** only the default compile-time setting, not any run-time changes 153 ** to that setting. 154 ** 155 ** See the [threading mode] documentation for additional information. 156 ** 157 ** Requirements: [H10101] [H10102] 158 */ 159 int sqlite3_threadsafe(void); 160 161 /* 162 ** CAPI3REF: Database Connection Handle {H12000} <S40200> 163 ** KEYWORDS: {database connection} {database connections} 164 ** 165 ** Each open SQLite database is represented by a pointer to an instance of 166 ** the opaque structure named "sqlite3". It is useful to think of an sqlite3 167 ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 168 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 169 ** is its destructor. There are many other interfaces (such as 170 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 171 ** [sqlite3_busy_timeout()] to name but three) that are methods on an 172 ** sqlite3 object. 173 */ 174 typedef struct sqlite3 sqlite3; 175 176 /* 177 ** CAPI3REF: 64-Bit Integer Types {H10200} <S10110> 178 ** KEYWORDS: sqlite_int64 sqlite_uint64 179 ** 180 ** Because there is no cross-platform way to specify 64-bit integer types 181 ** SQLite includes typedefs for 64-bit signed and unsigned integers. 182 ** 183 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 184 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards 185 ** compatibility only. 186 ** 187 ** Requirements: [H10201] [H10202] 188 */ 189 #ifdef SQLITE_INT64_TYPE 190 typedef SQLITE_INT64_TYPE sqlite_int64; 191 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 192 #elif defined(_MSC_VER) || defined(__BORLANDC__) 193 typedef __int64 sqlite_int64; 194 typedef unsigned __int64 sqlite_uint64; 195 #else 196 typedef long long int sqlite_int64; 197 typedef unsigned long long int sqlite_uint64; 198 #endif 199 typedef sqlite_int64 sqlite3_int64; 200 typedef sqlite_uint64 sqlite3_uint64; 201 202 /* 203 ** If compiling for a processor that lacks floating point support, 204 ** substitute integer for floating-point. 205 */ 206 #ifdef SQLITE_OMIT_FLOATING_POINT 207 # define double sqlite3_int64 208 #endif 209 210 /* 211 ** CAPI3REF: Closing A Database Connection {H12010} <S30100><S40200> 212 ** 213 ** This routine is the destructor for the [sqlite3] object. 214 ** 215 ** Applications should [sqlite3_finalize | finalize] all [prepared statements] 216 ** and [sqlite3_blob_close | close] all [BLOB handles] associated with 217 ** the [sqlite3] object prior to attempting to close the object. 218 ** The [sqlite3_next_stmt()] interface can be used to locate all 219 ** [prepared statements] associated with a [database connection] if desired. 220 ** Typical code might look like this: 221 ** 222 ** <blockquote><pre> 223 ** sqlite3_stmt *pStmt; 224 ** while( (pStmt = sqlite3_next_stmt(db, 0))!=0 ){ 225 ** sqlite3_finalize(pStmt); 226 ** } 227 ** </pre></blockquote> 228 ** 229 ** If [sqlite3_close()] is invoked while a transaction is open, 230 ** the transaction is automatically rolled back. 231 ** 232 ** The C parameter to [sqlite3_close(C)] must be either a NULL 233 ** pointer or an [sqlite3] object pointer obtained 234 ** from [sqlite3_open()], [sqlite3_open16()], or 235 ** [sqlite3_open_v2()], and not previously closed. 236 ** 237 ** Requirements: 238 ** [H12011] [H12012] [H12013] [H12014] [H12015] [H12019] 239 */ 240 int sqlite3_close(sqlite3 *); 241 242 /* 243 ** The type for a callback function. 244 ** This is legacy and deprecated. It is included for historical 245 ** compatibility and is not documented. 246 */ 247 typedef int (*sqlite3_callback)(void*,int,char**, char**); 248 249 /* 250 ** CAPI3REF: One-Step Query Execution Interface {H12100} <S10000> 251 ** 252 ** The sqlite3_exec() interface is a convenient way of running one or more 253 ** SQL statements without having to write a lot of C code. The UTF-8 encoded 254 ** SQL statements are passed in as the second parameter to sqlite3_exec(). 255 ** The statements are evaluated one by one until either an error or 256 ** an interrupt is encountered, or until they are all done. The 3rd parameter 257 ** is an optional callback that is invoked once for each row of any query 258 ** results produced by the SQL statements. The 5th parameter tells where 259 ** to write any error messages. 260 ** 261 ** The error message passed back through the 5th parameter is held 262 ** in memory obtained from [sqlite3_malloc()]. To avoid a memory leak, 263 ** the calling application should call [sqlite3_free()] on any error 264 ** message returned through the 5th parameter when it has finished using 265 ** the error message. 266 ** 267 ** If the SQL statement in the 2nd parameter is NULL or an empty string 268 ** or a string containing only whitespace and comments, then no SQL 269 ** statements are evaluated and the database is not changed. 270 ** 271 ** The sqlite3_exec() interface is implemented in terms of 272 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()]. 273 ** The sqlite3_exec() routine does nothing to the database that cannot be done 274 ** by [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()]. 275 ** 276 ** The first parameter to [sqlite3_exec()] must be an valid and open 277 ** [database connection]. 278 ** 279 ** The database connection must not be closed while 280 ** [sqlite3_exec()] is running. 281 ** 282 ** The calling function should use [sqlite3_free()] to free 283 ** the memory that *errmsg is left pointing at once the error 284 ** message is no longer needed. 285 ** 286 ** The SQL statement text in the 2nd parameter to [sqlite3_exec()] 287 ** must remain unchanged while [sqlite3_exec()] is running. 288 ** 289 ** Requirements: 290 ** [H12101] [H12102] [H12104] [H12105] [H12107] [H12110] [H12113] [H12116] 291 ** [H12119] [H12122] [H12125] [H12131] [H12134] [H12137] [H12138] 292 */ 293 int sqlite3_exec( 294 sqlite3*, /* An open database */ 295 const char *sql, /* SQL to be evaluated */ 296 int (*callback)(void*,int,char**,char**), /* Callback function */ 297 void *, /* 1st argument to callback */ 298 char **errmsg /* Error msg written here */ 299 ); 300 301 /* 302 ** CAPI3REF: Result Codes {H10210} <S10700> 303 ** KEYWORDS: SQLITE_OK {error code} {error codes} 304 ** KEYWORDS: {result code} {result codes} 305 ** 306 ** Many SQLite functions return an integer result code from the set shown 307 ** here in order to indicates success or failure. 308 ** 309 ** New error codes may be added in future versions of SQLite. 310 ** 311 ** See also: [SQLITE_IOERR_READ | extended result codes] 312 */ 313 #define SQLITE_OK 0 /* Successful result */ 314 /* beginning-of-error-codes */ 315 #define SQLITE_ERROR 1 /* SQL error or missing database */ 316 #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 317 #define SQLITE_PERM 3 /* Access permission denied */ 318 #define SQLITE_ABORT 4 /* Callback routine requested an abort */ 319 #define SQLITE_BUSY 5 /* The database file is locked */ 320 #define SQLITE_LOCKED 6 /* A table in the database is locked */ 321 #define SQLITE_NOMEM 7 /* A malloc() failed */ 322 #define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 323 #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 324 #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 325 #define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 326 #define SQLITE_NOTFOUND 12 /* NOT USED. Table or record not found */ 327 #define SQLITE_FULL 13 /* Insertion failed because database is full */ 328 #define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 329 #define SQLITE_PROTOCOL 15 /* NOT USED. Database lock protocol error */ 330 #define SQLITE_EMPTY 16 /* Database is empty */ 331 #define SQLITE_SCHEMA 17 /* The database schema changed */ 332 #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 333 #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 334 #define SQLITE_MISMATCH 20 /* Data type mismatch */ 335 #define SQLITE_MISUSE 21 /* Library used incorrectly */ 336 #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 337 #define SQLITE_AUTH 23 /* Authorization denied */ 338 #define SQLITE_FORMAT 24 /* Auxiliary database format error */ 339 #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 340 #define SQLITE_NOTADB 26 /* File opened that is not a database file */ 341 #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 342 #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 343 /* end-of-error-codes */ 344 345 /* 346 ** CAPI3REF: Extended Result Codes {H10220} <S10700> 347 ** KEYWORDS: {extended error code} {extended error codes} 348 ** KEYWORDS: {extended result code} {extended result codes} 349 ** 350 ** In its default configuration, SQLite API routines return one of 26 integer 351 ** [SQLITE_OK | result codes]. However, experience has shown that many of 352 ** these result codes are too coarse-grained. They do not provide as 353 ** much information about problems as programmers might like. In an effort to 354 ** address this, newer versions of SQLite (version 3.3.8 and later) include 355 ** support for additional result codes that provide more detailed information 356 ** about errors. The extended result codes are enabled or disabled 357 ** on a per database connection basis using the 358 ** [sqlite3_extended_result_codes()] API. 359 ** 360 ** Some of the available extended result codes are listed here. 361 ** One may expect the number of extended result codes will be expand 362 ** over time. Software that uses extended result codes should expect 363 ** to see new result codes in future releases of SQLite. 364 ** 365 ** The SQLITE_OK result code will never be extended. It will always 366 ** be exactly zero. 367 */ 368 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 369 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 370 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 371 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 372 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 373 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 374 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 375 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 376 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 377 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 378 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 379 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 380 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 381 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 382 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 383 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 384 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 385 386 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8) ) 387 388 /* 389 ** CAPI3REF: Flags For File Open Operations {H10230} <H11120> <H12700> 390 ** 391 ** These bit values are intended for use in the 392 ** 3rd parameter to the [sqlite3_open_v2()] interface and 393 ** in the 4th parameter to the xOpen method of the 394 ** [sqlite3_vfs] object. 395 */ 396 #define SQLITE_OPEN_READONLY 0x00000001 397 #define SQLITE_OPEN_READWRITE 0x00000002 398 #define SQLITE_OPEN_CREATE 0x00000004 399 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 400 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 401 #define SQLITE_OPEN_AUTOPROXY 0x00000020 402 #define SQLITE_OPEN_MAIN_DB 0x00000100 403 #define SQLITE_OPEN_TEMP_DB 0x00000200 404 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 405 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 406 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 407 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 408 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 409 #define SQLITE_OPEN_NOMUTEX 0x00008000 410 #define SQLITE_OPEN_FULLMUTEX 0x00010000 411 412 /* 413 ** CAPI3REF: Device Characteristics {H10240} <H11120> 414 ** 415 ** The xDeviceCapabilities method of the [sqlite3_io_methods] 416 ** object returns an integer which is a vector of the these 417 ** bit values expressing I/O characteristics of the mass storage 418 ** device that holds the file that the [sqlite3_io_methods] 419 ** refers to. 420 ** 421 ** The SQLITE_IOCAP_ATOMIC property means that all writes of 422 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 423 ** mean that writes of blocks that are nnn bytes in size and 424 ** are aligned to an address which is an integer multiple of 425 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 426 ** that when data is appended to a file, the data is appended 427 ** first then the size of the file is extended, never the other 428 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 429 ** information is written to disk in the same order as calls 430 ** to xWrite(). 431 */ 432 #define SQLITE_IOCAP_ATOMIC 0x00000001 433 #define SQLITE_IOCAP_ATOMIC512 0x00000002 434 #define SQLITE_IOCAP_ATOMIC1K 0x00000004 435 #define SQLITE_IOCAP_ATOMIC2K 0x00000008 436 #define SQLITE_IOCAP_ATOMIC4K 0x00000010 437 #define SQLITE_IOCAP_ATOMIC8K 0x00000020 438 #define SQLITE_IOCAP_ATOMIC16K 0x00000040 439 #define SQLITE_IOCAP_ATOMIC32K 0x00000080 440 #define SQLITE_IOCAP_ATOMIC64K 0x00000100 441 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200 442 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400 443 444 /* 445 ** CAPI3REF: File Locking Levels {H10250} <H11120> <H11310> 446 ** 447 ** SQLite uses one of these integer values as the second 448 ** argument to calls it makes to the xLock() and xUnlock() methods 449 ** of an [sqlite3_io_methods] object. 450 */ 451 #define SQLITE_LOCK_NONE 0 452 #define SQLITE_LOCK_SHARED 1 453 #define SQLITE_LOCK_RESERVED 2 454 #define SQLITE_LOCK_PENDING 3 455 #define SQLITE_LOCK_EXCLUSIVE 4 456 457 /* 458 ** CAPI3REF: Synchronization Type Flags {H10260} <H11120> 459 ** 460 ** When SQLite invokes the xSync() method of an 461 ** [sqlite3_io_methods] object it uses a combination of 462 ** these integer values as the second argument. 463 ** 464 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 465 ** sync operation only needs to flush data to mass storage. Inode 466 ** information need not be flushed. The SQLITE_SYNC_NORMAL flag means 467 ** to use normal fsync() semantics. The SQLITE_SYNC_FULL flag means 468 ** to use Mac OS X style fullsync instead of fsync(). 469 */ 470 #define SQLITE_SYNC_NORMAL 0x00002 471 #define SQLITE_SYNC_FULL 0x00003 472 #define SQLITE_SYNC_DATAONLY 0x00010 473 474 /* 475 ** CAPI3REF: OS Interface Open File Handle {H11110} <S20110> 476 ** 477 ** An [sqlite3_file] object represents an open file in the OS 478 ** interface layer. Individual OS interface implementations will 479 ** want to subclass this object by appending additional fields 480 ** for their own use. The pMethods entry is a pointer to an 481 ** [sqlite3_io_methods] object that defines methods for performing 482 ** I/O operations on the open file. 483 */ 484 typedef struct sqlite3_file sqlite3_file; 485 struct sqlite3_file { 486 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 487 }; 488 489 /* 490 ** CAPI3REF: OS Interface File Virtual Methods Object {H11120} <S20110> 491 ** 492 ** Every file opened by the [sqlite3_vfs] xOpen method populates an 493 ** [sqlite3_file] object (or, more commonly, a subclass of the 494 ** [sqlite3_file] object) with a pointer to an instance of this object. 495 ** This object defines the methods used to perform various operations 496 ** against the open file represented by the [sqlite3_file] object. 497 ** 498 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 499 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 500 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 501 ** flag may be ORed in to indicate that only the data of the file 502 ** and not its inode needs to be synced. 503 ** 504 ** The integer values to xLock() and xUnlock() are one of 505 ** <ul> 506 ** <li> [SQLITE_LOCK_NONE], 507 ** <li> [SQLITE_LOCK_SHARED], 508 ** <li> [SQLITE_LOCK_RESERVED], 509 ** <li> [SQLITE_LOCK_PENDING], or 510 ** <li> [SQLITE_LOCK_EXCLUSIVE]. 511 ** </ul> 512 ** xLock() increases the lock. xUnlock() decreases the lock. 513 ** The xCheckReservedLock() method checks whether any database connection, 514 ** either in this process or in some other process, is holding a RESERVED, 515 ** PENDING, or EXCLUSIVE lock on the file. It returns true 516 ** if such a lock exists and false otherwise. 517 ** 518 ** The xFileControl() method is a generic interface that allows custom 519 ** VFS implementations to directly control an open file using the 520 ** [sqlite3_file_control()] interface. The second "op" argument is an 521 ** integer opcode. The third argument is a generic pointer intended to 522 ** point to a structure that may contain arguments or space in which to 523 ** write return values. Potential uses for xFileControl() might be 524 ** functions to enable blocking locks with timeouts, to change the 525 ** locking strategy (for example to use dot-file locks), to inquire 526 ** about the status of a lock, or to break stale locks. The SQLite 527 ** core reserves all opcodes less than 100 for its own use. 528 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 529 ** Applications that define a custom xFileControl method should use opcodes 530 ** greater than 100 to avoid conflicts. 531 ** 532 ** The xSectorSize() method returns the sector size of the 533 ** device that underlies the file. The sector size is the 534 ** minimum write that can be performed without disturbing 535 ** other bytes in the file. The xDeviceCharacteristics() 536 ** method returns a bit vector describing behaviors of the 537 ** underlying device: 538 ** 539 ** <ul> 540 ** <li> [SQLITE_IOCAP_ATOMIC] 541 ** <li> [SQLITE_IOCAP_ATOMIC512] 542 ** <li> [SQLITE_IOCAP_ATOMIC1K] 543 ** <li> [SQLITE_IOCAP_ATOMIC2K] 544 ** <li> [SQLITE_IOCAP_ATOMIC4K] 545 ** <li> [SQLITE_IOCAP_ATOMIC8K] 546 ** <li> [SQLITE_IOCAP_ATOMIC16K] 547 ** <li> [SQLITE_IOCAP_ATOMIC32K] 548 ** <li> [SQLITE_IOCAP_ATOMIC64K] 549 ** <li> [SQLITE_IOCAP_SAFE_APPEND] 550 ** <li> [SQLITE_IOCAP_SEQUENTIAL] 551 ** </ul> 552 ** 553 ** The SQLITE_IOCAP_ATOMIC property means that all writes of 554 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 555 ** mean that writes of blocks that are nnn bytes in size and 556 ** are aligned to an address which is an integer multiple of 557 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 558 ** that when data is appended to a file, the data is appended 559 ** first then the size of the file is extended, never the other 560 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 561 ** information is written to disk in the same order as calls 562 ** to xWrite(). 563 ** 564 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 565 ** in the unread portions of the buffer with zeros. A VFS that 566 ** fails to zero-fill short reads might seem to work. However, 567 ** failure to zero-fill short reads will eventually lead to 568 ** database corruption. 569 */ 570 typedef struct sqlite3_io_methods sqlite3_io_methods; 571 struct sqlite3_io_methods { 572 int iVersion; 573 int (*xClose)(sqlite3_file*); 574 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 575 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 576 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 577 int (*xSync)(sqlite3_file*, int flags); 578 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 579 int (*xLock)(sqlite3_file*, int); 580 int (*xUnlock)(sqlite3_file*, int); 581 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 582 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 583 int (*xSectorSize)(sqlite3_file*); 584 int (*xDeviceCharacteristics)(sqlite3_file*); 585 /* Additional methods may be added in future releases */ 586 }; 587 588 /* 589 ** CAPI3REF: Standard File Control Opcodes {H11310} <S30800> 590 ** 591 ** These integer constants are opcodes for the xFileControl method 592 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 593 ** interface. 594 ** 595 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 596 ** opcode causes the xFileControl method to write the current state of 597 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 598 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 599 ** into an integer that the pArg argument points to. This capability 600 ** is used during testing and only needs to be supported when SQLITE_TEST 601 ** is defined. 602 */ 603 #define SQLITE_FCNTL_LOCKSTATE 1 604 #define SQLITE_GET_LOCKPROXYFILE 2 605 #define SQLITE_SET_LOCKPROXYFILE 3 606 #define SQLITE_LAST_ERRNO 4 607 608 /* 609 ** CAPI3REF: Mutex Handle {H17110} <S20130> 610 ** 611 ** The mutex module within SQLite defines [sqlite3_mutex] to be an 612 ** abstract type for a mutex object. The SQLite core never looks 613 ** at the internal representation of an [sqlite3_mutex]. It only 614 ** deals with pointers to the [sqlite3_mutex] object. 615 ** 616 ** Mutexes are created using [sqlite3_mutex_alloc()]. 617 */ 618 typedef struct sqlite3_mutex sqlite3_mutex; 619 620 /* 621 ** CAPI3REF: OS Interface Object {H11140} <S20100> 622 ** 623 ** An instance of the sqlite3_vfs object defines the interface between 624 ** the SQLite core and the underlying operating system. The "vfs" 625 ** in the name of the object stands for "virtual file system". 626 ** 627 ** The value of the iVersion field is initially 1 but may be larger in 628 ** future versions of SQLite. Additional fields may be appended to this 629 ** object when the iVersion value is increased. Note that the structure 630 ** of the sqlite3_vfs object changes in the transaction between 631 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 632 ** modified. 633 ** 634 ** The szOsFile field is the size of the subclassed [sqlite3_file] 635 ** structure used by this VFS. mxPathname is the maximum length of 636 ** a pathname in this VFS. 637 ** 638 ** Registered sqlite3_vfs objects are kept on a linked list formed by 639 ** the pNext pointer. The [sqlite3_vfs_register()] 640 ** and [sqlite3_vfs_unregister()] interfaces manage this list 641 ** in a thread-safe way. The [sqlite3_vfs_find()] interface 642 ** searches the list. Neither the application code nor the VFS 643 ** implementation should use the pNext pointer. 644 ** 645 ** The pNext field is the only field in the sqlite3_vfs 646 ** structure that SQLite will ever modify. SQLite will only access 647 ** or modify this field while holding a particular static mutex. 648 ** The application should never modify anything within the sqlite3_vfs 649 ** object once the object has been registered. 650 ** 651 ** The zName field holds the name of the VFS module. The name must 652 ** be unique across all VFS modules. 653 ** 654 ** SQLite will guarantee that the zFilename parameter to xOpen 655 ** is either a NULL pointer or string obtained 656 ** from xFullPathname(). SQLite further guarantees that 657 ** the string will be valid and unchanged until xClose() is 658 ** called. Because of the previous sentense, 659 ** the [sqlite3_file] can safely store a pointer to the 660 ** filename if it needs to remember the filename for some reason. 661 ** If the zFilename parameter is xOpen is a NULL pointer then xOpen 662 ** must invite its own temporary name for the file. Whenever the 663 ** xFilename parameter is NULL it will also be the case that the 664 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 665 ** 666 ** The flags argument to xOpen() includes all bits set in 667 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 668 ** or [sqlite3_open16()] is used, then flags includes at least 669 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 670 ** If xOpen() opens a file read-only then it sets *pOutFlags to 671 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 672 ** 673 ** SQLite will also add one of the following flags to the xOpen() 674 ** call, depending on the object being opened: 675 ** 676 ** <ul> 677 ** <li> [SQLITE_OPEN_MAIN_DB] 678 ** <li> [SQLITE_OPEN_MAIN_JOURNAL] 679 ** <li> [SQLITE_OPEN_TEMP_DB] 680 ** <li> [SQLITE_OPEN_TEMP_JOURNAL] 681 ** <li> [SQLITE_OPEN_TRANSIENT_DB] 682 ** <li> [SQLITE_OPEN_SUBJOURNAL] 683 ** <li> [SQLITE_OPEN_MASTER_JOURNAL] 684 ** </ul> 685 ** 686 ** The file I/O implementation can use the object type flags to 687 ** change the way it deals with files. For example, an application 688 ** that does not care about crash recovery or rollback might make 689 ** the open of a journal file a no-op. Writes to this journal would 690 ** also be no-ops, and any attempt to read the journal would return 691 ** SQLITE_IOERR. Or the implementation might recognize that a database 692 ** file will be doing page-aligned sector reads and writes in a random 693 ** order and set up its I/O subsystem accordingly. 694 ** 695 ** SQLite might also add one of the following flags to the xOpen method: 696 ** 697 ** <ul> 698 ** <li> [SQLITE_OPEN_DELETEONCLOSE] 699 ** <li> [SQLITE_OPEN_EXCLUSIVE] 700 ** </ul> 701 ** 702 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 703 ** deleted when it is closed. The [SQLITE_OPEN_DELETEONCLOSE] 704 ** will be set for TEMP databases, journals and for subjournals. 705 ** 706 ** The [SQLITE_OPEN_EXCLUSIVE] flag means the file should be opened 707 ** for exclusive access. This flag is set for all files except 708 ** for the main database file. 709 ** 710 ** At least szOsFile bytes of memory are allocated by SQLite 711 ** to hold the [sqlite3_file] structure passed as the third 712 ** argument to xOpen. The xOpen method does not have to 713 ** allocate the structure; it should just fill it in. 714 ** 715 ** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 716 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 717 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 718 ** to test whether a file is at least readable. The file can be a 719 ** directory. 720 ** 721 ** SQLite will always allocate at least mxPathname+1 bytes for the 722 ** output buffer xFullPathname. The exact size of the output buffer 723 ** is also passed as a parameter to both methods. If the output buffer 724 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 725 ** handled as a fatal error by SQLite, vfs implementations should endeavor 726 ** to prevent this by setting mxPathname to a sufficiently large value. 727 ** 728 ** The xRandomness(), xSleep(), and xCurrentTime() interfaces 729 ** are not strictly a part of the filesystem, but they are 730 ** included in the VFS structure for completeness. 731 ** The xRandomness() function attempts to return nBytes bytes 732 ** of good-quality randomness into zOut. The return value is 733 ** the actual number of bytes of randomness obtained. 734 ** The xSleep() method causes the calling thread to sleep for at 735 ** least the number of microseconds given. The xCurrentTime() 736 ** method returns a Julian Day Number for the current date and time. 737 ** 738 */ 739 typedef struct sqlite3_vfs sqlite3_vfs; 740 struct sqlite3_vfs { 741 int iVersion; /* Structure version number */ 742 int szOsFile; /* Size of subclassed sqlite3_file */ 743 int mxPathname; /* Maximum file pathname length */ 744 sqlite3_vfs *pNext; /* Next registered VFS */ 745 const char *zName; /* Name of this virtual file system */ 746 void *pAppData; /* Pointer to application-specific data */ 747 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 748 int flags, int *pOutFlags); 749 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 750 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 751 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 752 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 753 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 754 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 755 void (*xDlClose)(sqlite3_vfs*, void*); 756 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 757 int (*xSleep)(sqlite3_vfs*, int microseconds); 758 int (*xCurrentTime)(sqlite3_vfs*, double*); 759 int (*xGetLastError)(sqlite3_vfs*, int, char *); 760 /* New fields may be appended in figure versions. The iVersion 761 ** value will increment whenever this happens. */ 762 }; 763 764 /* 765 ** CAPI3REF: Flags for the xAccess VFS method {H11190} <H11140> 766 ** 767 ** These integer constants can be used as the third parameter to 768 ** the xAccess method of an [sqlite3_vfs] object. {END} They determine 769 ** what kind of permissions the xAccess method is looking for. 770 ** With SQLITE_ACCESS_EXISTS, the xAccess method 771 ** simply checks whether the file exists. 772 ** With SQLITE_ACCESS_READWRITE, the xAccess method 773 ** checks whether the file is both readable and writable. 774 ** With SQLITE_ACCESS_READ, the xAccess method 775 ** checks whether the file is readable. 776 */ 777 #define SQLITE_ACCESS_EXISTS 0 778 #define SQLITE_ACCESS_READWRITE 1 779 #define SQLITE_ACCESS_READ 2 780 781 /* 782 ** CAPI3REF: Initialize The SQLite Library {H10130} <S20000><S30100> 783 ** 784 ** The sqlite3_initialize() routine initializes the 785 ** SQLite library. The sqlite3_shutdown() routine 786 ** deallocates any resources that were allocated by sqlite3_initialize(). 787 ** 788 ** A call to sqlite3_initialize() is an "effective" call if it is 789 ** the first time sqlite3_initialize() is invoked during the lifetime of 790 ** the process, or if it is the first time sqlite3_initialize() is invoked 791 ** following a call to sqlite3_shutdown(). Only an effective call 792 ** of sqlite3_initialize() does any initialization. All other calls 793 ** are harmless no-ops. 794 ** 795 ** Among other things, sqlite3_initialize() shall invoke 796 ** sqlite3_os_init(). Similarly, sqlite3_shutdown() 797 ** shall invoke sqlite3_os_end(). 798 ** 799 ** The sqlite3_initialize() routine returns [SQLITE_OK] on success. 800 ** If for some reason, sqlite3_initialize() is unable to initialize 801 ** the library (perhaps it is unable to allocate a needed resource such 802 ** as a mutex) it returns an [error code] other than [SQLITE_OK]. 803 ** 804 ** The sqlite3_initialize() routine is called internally by many other 805 ** SQLite interfaces so that an application usually does not need to 806 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 807 ** calls sqlite3_initialize() so the SQLite library will be automatically 808 ** initialized when [sqlite3_open()] is called if it has not be initialized 809 ** already. However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 810 ** compile-time option, then the automatic calls to sqlite3_initialize() 811 ** are omitted and the application must call sqlite3_initialize() directly 812 ** prior to using any other SQLite interface. For maximum portability, 813 ** it is recommended that applications always invoke sqlite3_initialize() 814 ** directly prior to using any other SQLite interface. Future releases 815 ** of SQLite may require this. In other words, the behavior exhibited 816 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 817 ** default behavior in some future release of SQLite. 818 ** 819 ** The sqlite3_os_init() routine does operating-system specific 820 ** initialization of the SQLite library. The sqlite3_os_end() 821 ** routine undoes the effect of sqlite3_os_init(). Typical tasks 822 ** performed by these routines include allocation or deallocation 823 ** of static resources, initialization of global variables, 824 ** setting up a default [sqlite3_vfs] module, or setting up 825 ** a default configuration using [sqlite3_config()]. 826 ** 827 ** The application should never invoke either sqlite3_os_init() 828 ** or sqlite3_os_end() directly. The application should only invoke 829 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 830 ** interface is called automatically by sqlite3_initialize() and 831 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 832 ** implementations for sqlite3_os_init() and sqlite3_os_end() 833 ** are built into SQLite when it is compiled for unix, windows, or os/2. 834 ** When built for other platforms (using the [SQLITE_OS_OTHER=1] compile-time 835 ** option) the application must supply a suitable implementation for 836 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 837 ** implementation of sqlite3_os_init() or sqlite3_os_end() 838 ** must return [SQLITE_OK] on success and some other [error code] upon 839 ** failure. 840 */ 841 int sqlite3_initialize(void); 842 int sqlite3_shutdown(void); 843 int sqlite3_os_init(void); 844 int sqlite3_os_end(void); 845 846 /* 847 ** CAPI3REF: Configuring The SQLite Library {H14100} <S20000><S30200> 848 ** EXPERIMENTAL 849 ** 850 ** The sqlite3_config() interface is used to make global configuration 851 ** changes to SQLite in order to tune SQLite to the specific needs of 852 ** the application. The default configuration is recommended for most 853 ** applications and so this routine is usually not necessary. It is 854 ** provided to support rare applications with unusual needs. 855 ** 856 ** The sqlite3_config() interface is not threadsafe. The application 857 ** must insure that no other SQLite interfaces are invoked by other 858 ** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 859 ** may only be invoked prior to library initialization using 860 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 861 ** Note, however, that sqlite3_config() can be called as part of the 862 ** implementation of an application-defined [sqlite3_os_init()]. 863 ** 864 ** The first argument to sqlite3_config() is an integer 865 ** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines 866 ** what property of SQLite is to be configured. Subsequent arguments 867 ** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option] 868 ** in the first argument. 869 ** 870 ** When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 871 ** If the option is unknown or SQLite is unable to set the option 872 ** then this routine returns a non-zero [error code]. 873 ** 874 ** Requirements: 875 ** [H14103] [H14106] [H14120] [H14123] [H14126] [H14129] [H14132] [H14135] 876 ** [H14138] [H14141] [H14144] [H14147] [H14150] [H14153] [H14156] [H14159] 877 ** [H14162] [H14165] [H14168] 878 */ 879 SQLITE_EXPERIMENTAL int sqlite3_config(int, ...); 880 881 /* 882 ** CAPI3REF: Configure database connections {H14200} <S20000> 883 ** EXPERIMENTAL 884 ** 885 ** The sqlite3_db_config() interface is used to make configuration 886 ** changes to a [database connection]. The interface is similar to 887 ** [sqlite3_config()] except that the changes apply to a single 888 ** [database connection] (specified in the first argument). The 889 ** sqlite3_db_config() interface can only be used immediately after 890 ** the database connection is created using [sqlite3_open()], 891 ** [sqlite3_open16()], or [sqlite3_open_v2()]. 892 ** 893 ** The second argument to sqlite3_db_config(D,V,...) is the 894 ** configuration verb - an integer code that indicates what 895 ** aspect of the [database connection] is being configured. 896 ** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE]. 897 ** New verbs are likely to be added in future releases of SQLite. 898 ** Additional arguments depend on the verb. 899 ** 900 ** Requirements: 901 ** [H14203] [H14206] [H14209] [H14212] [H14215] 902 */ 903 SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...); 904 905 /* 906 ** CAPI3REF: Memory Allocation Routines {H10155} <S20120> 907 ** EXPERIMENTAL 908 ** 909 ** An instance of this object defines the interface between SQLite 910 ** and low-level memory allocation routines. 911 ** 912 ** This object is used in only one place in the SQLite interface. 913 ** A pointer to an instance of this object is the argument to 914 ** [sqlite3_config()] when the configuration option is 915 ** [SQLITE_CONFIG_MALLOC]. By creating an instance of this object 916 ** and passing it to [sqlite3_config()] during configuration, an 917 ** application can specify an alternative memory allocation subsystem 918 ** for SQLite to use for all of its dynamic memory needs. 919 ** 920 ** Note that SQLite comes with a built-in memory allocator that is 921 ** perfectly adequate for the overwhelming majority of applications 922 ** and that this object is only useful to a tiny minority of applications 923 ** with specialized memory allocation requirements. This object is 924 ** also used during testing of SQLite in order to specify an alternative 925 ** memory allocator that simulates memory out-of-memory conditions in 926 ** order to verify that SQLite recovers gracefully from such 927 ** conditions. 928 ** 929 ** The xMalloc, xFree, and xRealloc methods must work like the 930 ** malloc(), free(), and realloc() functions from the standard library. 931 ** 932 ** xSize should return the allocated size of a memory allocation 933 ** previously obtained from xMalloc or xRealloc. The allocated size 934 ** is always at least as big as the requested size but may be larger. 935 ** 936 ** The xRoundup method returns what would be the allocated size of 937 ** a memory allocation given a particular requested size. Most memory 938 ** allocators round up memory allocations at least to the next multiple 939 ** of 8. Some allocators round up to a larger multiple or to a power of 2. 940 ** 941 ** The xInit method initializes the memory allocator. (For example, 942 ** it might allocate any require mutexes or initialize internal data 943 ** structures. The xShutdown method is invoked (indirectly) by 944 ** [sqlite3_shutdown()] and should deallocate any resources acquired 945 ** by xInit. The pAppData pointer is used as the only parameter to 946 ** xInit and xShutdown. 947 */ 948 typedef struct sqlite3_mem_methods sqlite3_mem_methods; 949 struct sqlite3_mem_methods { 950 void *(*xMalloc)(int); /* Memory allocation function */ 951 void (*xFree)(void*); /* Free a prior allocation */ 952 void *(*xRealloc)(void*,int); /* Resize an allocation */ 953 int (*xSize)(void*); /* Return the size of an allocation */ 954 int (*xRoundup)(int); /* Round up request size to allocation size */ 955 int (*xInit)(void*); /* Initialize the memory allocator */ 956 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 957 void *pAppData; /* Argument to xInit() and xShutdown() */ 958 }; 959 960 /* 961 ** CAPI3REF: Configuration Options {H10160} <S20000> 962 ** EXPERIMENTAL 963 ** 964 ** These constants are the available integer configuration options that 965 ** can be passed as the first argument to the [sqlite3_config()] interface. 966 ** 967 ** New configuration options may be added in future releases of SQLite. 968 ** Existing configuration options might be discontinued. Applications 969 ** should check the return code from [sqlite3_config()] to make sure that 970 ** the call worked. The [sqlite3_config()] interface will return a 971 ** non-zero [error code] if a discontinued or unsupported configuration option 972 ** is invoked. 973 ** 974 ** <dl> 975 ** <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 976 ** <dd>There are no arguments to this option. This option disables 977 ** all mutexing and puts SQLite into a mode where it can only be used 978 ** by a single thread.</dd> 979 ** 980 ** <dt>SQLITE_CONFIG_MULTITHREAD</dt> 981 ** <dd>There are no arguments to this option. This option disables 982 ** mutexing on [database connection] and [prepared statement] objects. 983 ** The application is responsible for serializing access to 984 ** [database connections] and [prepared statements]. But other mutexes 985 ** are enabled so that SQLite will be safe to use in a multi-threaded 986 ** environment as long as no two threads attempt to use the same 987 ** [database connection] at the same time. See the [threading mode] 988 ** documentation for additional information.</dd> 989 ** 990 ** <dt>SQLITE_CONFIG_SERIALIZED</dt> 991 ** <dd>There are no arguments to this option. This option enables 992 ** all mutexes including the recursive 993 ** mutexes on [database connection] and [prepared statement] objects. 994 ** In this mode (which is the default when SQLite is compiled with 995 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 996 ** to [database connections] and [prepared statements] so that the 997 ** application is free to use the same [database connection] or the 998 ** same [prepared statement] in different threads at the same time. 999 ** See the [threading mode] documentation for additional information.</dd> 1000 ** 1001 ** <dt>SQLITE_CONFIG_MALLOC</dt> 1002 ** <dd>This option takes a single argument which is a pointer to an 1003 ** instance of the [sqlite3_mem_methods] structure. The argument specifies 1004 ** alternative low-level memory allocation routines to be used in place of 1005 ** the memory allocation routines built into SQLite.</dd> 1006 ** 1007 ** <dt>SQLITE_CONFIG_GETMALLOC</dt> 1008 ** <dd>This option takes a single argument which is a pointer to an 1009 ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1010 ** structure is filled with the currently defined memory allocation routines. 1011 ** This option can be used to overload the default memory allocation 1012 ** routines with a wrapper that simulations memory allocation failure or 1013 ** tracks memory usage, for example.</dd> 1014 ** 1015 ** <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1016 ** <dd>This option takes single argument of type int, interpreted as a 1017 ** boolean, which enables or disables the collection of memory allocation 1018 ** statistics. When disabled, the following SQLite interfaces become 1019 ** non-operational: 1020 ** <ul> 1021 ** <li> [sqlite3_memory_used()] 1022 ** <li> [sqlite3_memory_highwater()] 1023 ** <li> [sqlite3_soft_heap_limit()] 1024 ** <li> [sqlite3_status()] 1025 ** </ul> 1026 ** </dd> 1027 ** 1028 ** <dt>SQLITE_CONFIG_SCRATCH</dt> 1029 ** <dd>This option specifies a static memory buffer that SQLite can use for 1030 ** scratch memory. There are three arguments: A pointer to the memory, the 1031 ** size of each scratch buffer (sz), and the number of buffers (N). The sz 1032 ** argument must be a multiple of 16. The sz parameter should be a few bytes 1033 ** larger than the actual scratch space required due internal overhead. 1034 ** The first 1035 ** argument should point to an allocation of at least sz*N bytes of memory. 1036 ** SQLite will use no more than one scratch buffer at once per thread, so 1037 ** N should be set to the expected maximum number of threads. The sz 1038 ** parameter should be 6 times the size of the largest database page size. 1039 ** Scratch buffers are used as part of the btree balance operation. If 1040 ** The btree balancer needs additional memory beyond what is provided by 1041 ** scratch buffers or if no scratch buffer space is specified, then SQLite 1042 ** goes to [sqlite3_malloc()] to obtain the memory it needs.</dd> 1043 ** 1044 ** <dt>SQLITE_CONFIG_PAGECACHE</dt> 1045 ** <dd>This option specifies a static memory buffer that SQLite can use for 1046 ** the database page cache with the default page cache implemenation. 1047 ** This configuration should not be used if an application-define page 1048 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option. 1049 ** There are three arguments to this option: A pointer to the 1050 ** memory, the size of each page buffer (sz), and the number of pages (N). 1051 ** The sz argument must be a power of two between 512 and 32768. The first 1052 ** argument should point to an allocation of at least sz*N bytes of memory. 1053 ** SQLite will use the memory provided by the first argument to satisfy its 1054 ** memory needs for the first N pages that it adds to cache. If additional 1055 ** page cache memory is needed beyond what is provided by this option, then 1056 ** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1057 ** The implementation might use one or more of the N buffers to hold 1058 ** memory accounting information. </dd> 1059 ** 1060 ** <dt>SQLITE_CONFIG_HEAP</dt> 1061 ** <dd>This option specifies a static memory buffer that SQLite will use 1062 ** for all of its dynamic memory allocation needs beyond those provided 1063 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1064 ** There are three arguments: A pointer to the memory, the number of 1065 ** bytes in the memory buffer, and the minimum allocation size. If 1066 ** the first pointer (the memory pointer) is NULL, then SQLite reverts 1067 ** to using its default memory allocator (the system malloc() implementation), 1068 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. If the 1069 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1070 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1071 ** allocator is engaged to handle all of SQLites memory allocation needs.</dd> 1072 ** 1073 ** <dt>SQLITE_CONFIG_MUTEX</dt> 1074 ** <dd>This option takes a single argument which is a pointer to an 1075 ** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1076 ** alternative low-level mutex routines to be used in place 1077 ** the mutex routines built into SQLite.</dd> 1078 ** 1079 ** <dt>SQLITE_CONFIG_GETMUTEX</dt> 1080 ** <dd>This option takes a single argument which is a pointer to an 1081 ** instance of the [sqlite3_mutex_methods] structure. The 1082 ** [sqlite3_mutex_methods] 1083 ** structure is filled with the currently defined mutex routines. 1084 ** This option can be used to overload the default mutex allocation 1085 ** routines with a wrapper used to track mutex usage for performance 1086 ** profiling or testing, for example.</dd> 1087 ** 1088 ** <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1089 ** <dd>This option takes two arguments that determine the default 1090 ** memory allcation lookaside optimization. The first argument is the 1091 ** size of each lookaside buffer slot and the second is the number of 1092 ** slots allocated to each database connection.</dd> 1093 ** 1094 ** <dt>SQLITE_CONFIG_PCACHE</dt> 1095 ** <dd>This option takes a single argument which is a pointer to 1096 ** an [sqlite3_pcache_methods] object. This object specifies the interface 1097 ** to a custom page cache implementation. SQLite makes a copy of the 1098 ** object and uses it for page cache memory allocations.</dd> 1099 ** 1100 ** <dt>SQLITE_CONFIG_GETPCACHE</dt> 1101 ** <dd>This option takes a single argument which is a pointer to an 1102 ** [sqlite3_pcache_methods] object. SQLite copies of the current 1103 ** page cache implementation into that object.</dd> 1104 ** 1105 ** </dl> 1106 */ 1107 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1108 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1109 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1110 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1111 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1112 #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1113 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1114 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1115 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1116 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1117 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1118 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1119 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1120 #define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */ 1121 #define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */ 1122 1123 /* 1124 ** CAPI3REF: Configuration Options {H10170} <S20000> 1125 ** EXPERIMENTAL 1126 ** 1127 ** These constants are the available integer configuration options that 1128 ** can be passed as the second argument to the [sqlite3_db_config()] interface. 1129 ** 1130 ** New configuration options may be added in future releases of SQLite. 1131 ** Existing configuration options might be discontinued. Applications 1132 ** should check the return code from [sqlite3_db_config()] to make sure that 1133 ** the call worked. The [sqlite3_db_config()] interface will return a 1134 ** non-zero [error code] if a discontinued or unsupported configuration option 1135 ** is invoked. 1136 ** 1137 ** <dl> 1138 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1139 ** <dd>This option takes three additional arguments that determine the 1140 ** [lookaside memory allocator] configuration for the [database connection]. 1141 ** The first argument (the third parameter to [sqlite3_db_config()] is a 1142 ** pointer to a memory buffer to use for lookaside memory. The first 1143 ** argument may be NULL in which case SQLite will allocate the lookaside 1144 ** buffer itself using [sqlite3_malloc()]. The second argument is the 1145 ** size of each lookaside buffer slot and the third argument is the number of 1146 ** slots. The size of the buffer in the first argument must be greater than 1147 ** or equal to the product of the second and third arguments.</dd> 1148 ** 1149 ** </dl> 1150 */ 1151 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1152 1153 1154 /* 1155 ** CAPI3REF: Enable Or Disable Extended Result Codes {H12200} <S10700> 1156 ** 1157 ** The sqlite3_extended_result_codes() routine enables or disables the 1158 ** [extended result codes] feature of SQLite. The extended result 1159 ** codes are disabled by default for historical compatibility considerations. 1160 ** 1161 ** Requirements: 1162 ** [H12201] [H12202] 1163 */ 1164 int sqlite3_extended_result_codes(sqlite3*, int onoff); 1165 1166 /* 1167 ** CAPI3REF: Last Insert Rowid {H12220} <S10700> 1168 ** 1169 ** Each entry in an SQLite table has a unique 64-bit signed 1170 ** integer key called the [ROWID | "rowid"]. The rowid is always available 1171 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1172 ** names are not also used by explicitly declared columns. If 1173 ** the table has a column of type [INTEGER PRIMARY KEY] then that column 1174 ** is another alias for the rowid. 1175 ** 1176 ** This routine returns the [rowid] of the most recent 1177 ** successful [INSERT] into the database from the [database connection] 1178 ** in the first argument. If no successful [INSERT]s 1179 ** have ever occurred on that database connection, zero is returned. 1180 ** 1181 ** If an [INSERT] occurs within a trigger, then the [rowid] of the inserted 1182 ** row is returned by this routine as long as the trigger is running. 1183 ** But once the trigger terminates, the value returned by this routine 1184 ** reverts to the last value inserted before the trigger fired. 1185 ** 1186 ** An [INSERT] that fails due to a constraint violation is not a 1187 ** successful [INSERT] and does not change the value returned by this 1188 ** routine. Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1189 ** and INSERT OR ABORT make no changes to the return value of this 1190 ** routine when their insertion fails. When INSERT OR REPLACE 1191 ** encounters a constraint violation, it does not fail. The 1192 ** INSERT continues to completion after deleting rows that caused 1193 ** the constraint problem so INSERT OR REPLACE will always change 1194 ** the return value of this interface. 1195 ** 1196 ** For the purposes of this routine, an [INSERT] is considered to 1197 ** be successful even if it is subsequently rolled back. 1198 ** 1199 ** Requirements: 1200 ** [H12221] [H12223] 1201 ** 1202 ** If a separate thread performs a new [INSERT] on the same 1203 ** database connection while the [sqlite3_last_insert_rowid()] 1204 ** function is running and thus changes the last insert [rowid], 1205 ** then the value returned by [sqlite3_last_insert_rowid()] is 1206 ** unpredictable and might not equal either the old or the new 1207 ** last insert [rowid]. 1208 */ 1209 sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1210 1211 /* 1212 ** CAPI3REF: Count The Number Of Rows Modified {H12240} <S10600> 1213 ** 1214 ** This function returns the number of database rows that were changed 1215 ** or inserted or deleted by the most recently completed SQL statement 1216 ** on the [database connection] specified by the first parameter. 1217 ** Only changes that are directly specified by the [INSERT], [UPDATE], 1218 ** or [DELETE] statement are counted. Auxiliary changes caused by 1219 ** triggers are not counted. Use the [sqlite3_total_changes()] function 1220 ** to find the total number of changes including changes caused by triggers. 1221 ** 1222 ** A "row change" is a change to a single row of a single table 1223 ** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1224 ** are changed as side effects of REPLACE constraint resolution, 1225 ** rollback, ABORT processing, DROP TABLE, or by any other 1226 ** mechanisms do not count as direct row changes. 1227 ** 1228 ** A "trigger context" is a scope of execution that begins and 1229 ** ends with the script of a trigger. Most SQL statements are 1230 ** evaluated outside of any trigger. This is the "top level" 1231 ** trigger context. If a trigger fires from the top level, a 1232 ** new trigger context is entered for the duration of that one 1233 ** trigger. Subtriggers create subcontexts for their duration. 1234 ** 1235 ** Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1236 ** not create a new trigger context. 1237 ** 1238 ** This function returns the number of direct row changes in the 1239 ** most recent INSERT, UPDATE, or DELETE statement within the same 1240 ** trigger context. 1241 ** 1242 ** Thus, when called from the top level, this function returns the 1243 ** number of changes in the most recent INSERT, UPDATE, or DELETE 1244 ** that also occurred at the top level. Within the body of a trigger, 1245 ** the sqlite3_changes() interface can be called to find the number of 1246 ** changes in the most recently completed INSERT, UPDATE, or DELETE 1247 ** statement within the body of the same trigger. 1248 ** However, the number returned does not include changes 1249 ** caused by subtriggers since those have their own context. 1250 ** 1251 ** SQLite implements the command "DELETE FROM table" without a WHERE clause 1252 ** by dropping and recreating the table. Doing so is much faster than going 1253 ** through and deleting individual elements from the table. Because of this 1254 ** optimization, the deletions in "DELETE FROM table" are not row changes and 1255 ** will not be counted by the sqlite3_changes() or [sqlite3_total_changes()] 1256 ** functions, regardless of the number of elements that were originally 1257 ** in the table. To get an accurate count of the number of rows deleted, use 1258 ** "DELETE FROM table WHERE 1" instead. Or recompile using the 1259 ** [SQLITE_OMIT_TRUNCATE_OPTIMIZATION] compile-time option to disable the 1260 ** optimization on all queries. 1261 ** 1262 ** Requirements: 1263 ** [H12241] [H12243] 1264 ** 1265 ** If a separate thread makes changes on the same database connection 1266 ** while [sqlite3_changes()] is running then the value returned 1267 ** is unpredictable and not meaningful. 1268 */ 1269 int sqlite3_changes(sqlite3*); 1270 1271 /* 1272 ** CAPI3REF: Total Number Of Rows Modified {H12260} <S10600> 1273 ** 1274 ** This function returns the number of row changes caused by INSERT, 1275 ** UPDATE or DELETE statements since the [database connection] was opened. 1276 ** The count includes all changes from all trigger contexts. However, 1277 ** the count does not include changes used to implement REPLACE constraints, 1278 ** do rollbacks or ABORT processing, or DROP table processing. 1279 ** The changes are counted as soon as the statement that makes them is 1280 ** completed (when the statement handle is passed to [sqlite3_reset()] or 1281 ** [sqlite3_finalize()]). 1282 ** 1283 ** SQLite implements the command "DELETE FROM table" without a WHERE clause 1284 ** by dropping and recreating the table. (This is much faster than going 1285 ** through and deleting individual elements from the table.) Because of this 1286 ** optimization, the deletions in "DELETE FROM table" are not row changes and 1287 ** will not be counted by the sqlite3_changes() or [sqlite3_total_changes()] 1288 ** functions, regardless of the number of elements that were originally 1289 ** in the table. To get an accurate count of the number of rows deleted, use 1290 ** "DELETE FROM table WHERE 1" instead. Or recompile using the 1291 ** [SQLITE_OMIT_TRUNCATE_OPTIMIZATION] compile-time option to disable the 1292 ** optimization on all queries. 1293 ** 1294 ** See also the [sqlite3_changes()] interface. 1295 ** 1296 ** Requirements: 1297 ** [H12261] [H12263] 1298 ** 1299 ** If a separate thread makes changes on the same database connection 1300 ** while [sqlite3_total_changes()] is running then the value 1301 ** returned is unpredictable and not meaningful. 1302 */ 1303 int sqlite3_total_changes(sqlite3*); 1304 1305 /* 1306 ** CAPI3REF: Interrupt A Long-Running Query {H12270} <S30500> 1307 ** 1308 ** This function causes any pending database operation to abort and 1309 ** return at its earliest opportunity. This routine is typically 1310 ** called in response to a user action such as pressing "Cancel" 1311 ** or Ctrl-C where the user wants a long query operation to halt 1312 ** immediately. 1313 ** 1314 ** It is safe to call this routine from a thread different from the 1315 ** thread that is currently running the database operation. But it 1316 ** is not safe to call this routine with a [database connection] that 1317 ** is closed or might close before sqlite3_interrupt() returns. 1318 ** 1319 ** If an SQL operation is very nearly finished at the time when 1320 ** sqlite3_interrupt() is called, then it might not have an opportunity 1321 ** to be interrupted and might continue to completion. 1322 ** 1323 ** An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1324 ** If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1325 ** that is inside an explicit transaction, then the entire transaction 1326 ** will be rolled back automatically. 1327 ** 1328 ** A call to sqlite3_interrupt() has no effect on SQL statements 1329 ** that are started after sqlite3_interrupt() returns. 1330 ** 1331 ** Requirements: 1332 ** [H12271] [H12272] 1333 ** 1334 ** If the database connection closes while [sqlite3_interrupt()] 1335 ** is running then bad things will likely happen. 1336 */ 1337 void sqlite3_interrupt(sqlite3*); 1338 1339 /* 1340 ** CAPI3REF: Determine If An SQL Statement Is Complete {H10510} <S70200> 1341 ** 1342 ** These routines are useful for command-line input to determine if the 1343 ** currently entered text seems to form complete a SQL statement or 1344 ** if additional input is needed before sending the text into 1345 ** SQLite for parsing. These routines return true if the input string 1346 ** appears to be a complete SQL statement. A statement is judged to be 1347 ** complete if it ends with a semicolon token and is not a fragment of a 1348 ** CREATE TRIGGER statement. Semicolons that are embedded within 1349 ** string literals or quoted identifier names or comments are not 1350 ** independent tokens (they are part of the token in which they are 1351 ** embedded) and thus do not count as a statement terminator. 1352 ** 1353 ** These routines do not parse the SQL statements thus 1354 ** will not detect syntactically incorrect SQL. 1355 ** 1356 ** Requirements: [H10511] [H10512] 1357 ** 1358 ** The input to [sqlite3_complete()] must be a zero-terminated 1359 ** UTF-8 string. 1360 ** 1361 ** The input to [sqlite3_complete16()] must be a zero-terminated 1362 ** UTF-16 string in native byte order. 1363 */ 1364 int sqlite3_complete(const char *sql); 1365 int sqlite3_complete16(const void *sql); 1366 1367 /* 1368 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors {H12310} <S40400> 1369 ** 1370 ** This routine sets a callback function that might be invoked whenever 1371 ** an attempt is made to open a database table that another thread 1372 ** or process has locked. 1373 ** 1374 ** If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1375 ** is returned immediately upon encountering the lock. If the busy callback 1376 ** is not NULL, then the callback will be invoked with two arguments. 1377 ** 1378 ** The first argument to the handler is a copy of the void* pointer which 1379 ** is the third argument to sqlite3_busy_handler(). The second argument to 1380 ** the handler callback is the number of times that the busy handler has 1381 ** been invoked for this locking event. If the 1382 ** busy callback returns 0, then no additional attempts are made to 1383 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1384 ** If the callback returns non-zero, then another attempt 1385 ** is made to open the database for reading and the cycle repeats. 1386 ** 1387 ** The presence of a busy handler does not guarantee that it will be invoked 1388 ** when there is lock contention. If SQLite determines that invoking the busy 1389 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1390 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1391 ** Consider a scenario where one process is holding a read lock that 1392 ** it is trying to promote to a reserved lock and 1393 ** a second process is holding a reserved lock that it is trying 1394 ** to promote to an exclusive lock. The first process cannot proceed 1395 ** because it is blocked by the second and the second process cannot 1396 ** proceed because it is blocked by the first. If both processes 1397 ** invoke the busy handlers, neither will make any progress. Therefore, 1398 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1399 ** will induce the first process to release its read lock and allow 1400 ** the second process to proceed. 1401 ** 1402 ** The default busy callback is NULL. 1403 ** 1404 ** The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1405 ** when SQLite is in the middle of a large transaction where all the 1406 ** changes will not fit into the in-memory cache. SQLite will 1407 ** already hold a RESERVED lock on the database file, but it needs 1408 ** to promote this lock to EXCLUSIVE so that it can spill cache 1409 ** pages into the database file without harm to concurrent 1410 ** readers. If it is unable to promote the lock, then the in-memory 1411 ** cache will be left in an inconsistent state and so the error 1412 ** code is promoted from the relatively benign [SQLITE_BUSY] to 1413 ** the more severe [SQLITE_IOERR_BLOCKED]. This error code promotion 1414 ** forces an automatic rollback of the changes. See the 1415 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1416 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1417 ** this is important. 1418 ** 1419 ** There can only be a single busy handler defined for each 1420 ** [database connection]. Setting a new busy handler clears any 1421 ** previously set handler. Note that calling [sqlite3_busy_timeout()] 1422 ** will also set or clear the busy handler. 1423 ** 1424 ** The busy callback should not take any actions which modify the 1425 ** database connection that invoked the busy handler. Any such actions 1426 ** result in undefined behavior. 1427 ** 1428 ** Requirements: 1429 ** [H12311] [H12312] [H12314] [H12316] [H12318] 1430 ** 1431 ** A busy handler must not close the database connection 1432 ** or [prepared statement] that invoked the busy handler. 1433 */ 1434 int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1435 1436 /* 1437 ** CAPI3REF: Set A Busy Timeout {H12340} <S40410> 1438 ** 1439 ** This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1440 ** for a specified amount of time when a table is locked. The handler 1441 ** will sleep multiple times until at least "ms" milliseconds of sleeping 1442 ** have accumulated. {H12343} After "ms" milliseconds of sleeping, 1443 ** the handler returns 0 which causes [sqlite3_step()] to return 1444 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1445 ** 1446 ** Calling this routine with an argument less than or equal to zero 1447 ** turns off all busy handlers. 1448 ** 1449 ** There can only be a single busy handler for a particular 1450 ** [database connection] any any given moment. If another busy handler 1451 ** was defined (using [sqlite3_busy_handler()]) prior to calling 1452 ** this routine, that other busy handler is cleared. 1453 ** 1454 ** Requirements: 1455 ** [H12341] [H12343] [H12344] 1456 */ 1457 int sqlite3_busy_timeout(sqlite3*, int ms); 1458 1459 /* 1460 ** CAPI3REF: Convenience Routines For Running Queries {H12370} <S10000> 1461 ** 1462 ** Definition: A <b>result table</b> is memory data structure created by the 1463 ** [sqlite3_get_table()] interface. A result table records the 1464 ** complete query results from one or more queries. 1465 ** 1466 ** The table conceptually has a number of rows and columns. But 1467 ** these numbers are not part of the result table itself. These 1468 ** numbers are obtained separately. Let N be the number of rows 1469 ** and M be the number of columns. 1470 ** 1471 ** A result table is an array of pointers to zero-terminated UTF-8 strings. 1472 ** There are (N+1)*M elements in the array. The first M pointers point 1473 ** to zero-terminated strings that contain the names of the columns. 1474 ** The remaining entries all point to query results. NULL values result 1475 ** in NULL pointers. All other values are in their UTF-8 zero-terminated 1476 ** string representation as returned by [sqlite3_column_text()]. 1477 ** 1478 ** A result table might consist of one or more memory allocations. 1479 ** It is not safe to pass a result table directly to [sqlite3_free()]. 1480 ** A result table should be deallocated using [sqlite3_free_table()]. 1481 ** 1482 ** As an example of the result table format, suppose a query result 1483 ** is as follows: 1484 ** 1485 ** <blockquote><pre> 1486 ** Name | Age 1487 ** ----------------------- 1488 ** Alice | 43 1489 ** Bob | 28 1490 ** Cindy | 21 1491 ** </pre></blockquote> 1492 ** 1493 ** There are two column (M==2) and three rows (N==3). Thus the 1494 ** result table has 8 entries. Suppose the result table is stored 1495 ** in an array names azResult. Then azResult holds this content: 1496 ** 1497 ** <blockquote><pre> 1498 ** azResult[0] = "Name"; 1499 ** azResult[1] = "Age"; 1500 ** azResult[2] = "Alice"; 1501 ** azResult[3] = "43"; 1502 ** azResult[4] = "Bob"; 1503 ** azResult[5] = "28"; 1504 ** azResult[6] = "Cindy"; 1505 ** azResult[7] = "21"; 1506 ** </pre></blockquote> 1507 ** 1508 ** The sqlite3_get_table() function evaluates one or more 1509 ** semicolon-separated SQL statements in the zero-terminated UTF-8 1510 ** string of its 2nd parameter. It returns a result table to the 1511 ** pointer given in its 3rd parameter. 1512 ** 1513 ** After the calling function has finished using the result, it should 1514 ** pass the pointer to the result table to sqlite3_free_table() in order to 1515 ** release the memory that was malloced. Because of the way the 1516 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1517 ** function must not try to call [sqlite3_free()] directly. Only 1518 ** [sqlite3_free_table()] is able to release the memory properly and safely. 1519 ** 1520 ** The sqlite3_get_table() interface is implemented as a wrapper around 1521 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 1522 ** to any internal data structures of SQLite. It uses only the public 1523 ** interface defined here. As a consequence, errors that occur in the 1524 ** wrapper layer outside of the internal [sqlite3_exec()] call are not 1525 ** reflected in subsequent calls to [sqlite3_errcode()] or [sqlite3_errmsg()]. 1526 ** 1527 ** Requirements: 1528 ** [H12371] [H12373] [H12374] [H12376] [H12379] [H12382] 1529 */ 1530 int sqlite3_get_table( 1531 sqlite3 *db, /* An open database */ 1532 const char *zSql, /* SQL to be evaluated */ 1533 char ***pazResult, /* Results of the query */ 1534 int *pnRow, /* Number of result rows written here */ 1535 int *pnColumn, /* Number of result columns written here */ 1536 char **pzErrmsg /* Error msg written here */ 1537 ); 1538 void sqlite3_free_table(char **result); 1539 1540 /* 1541 ** CAPI3REF: Formatted String Printing Functions {H17400} <S70000><S20000> 1542 ** 1543 ** These routines are workalikes of the "printf()" family of functions 1544 ** from the standard C library. 1545 ** 1546 ** The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 1547 ** results into memory obtained from [sqlite3_malloc()]. 1548 ** The strings returned by these two routines should be 1549 ** released by [sqlite3_free()]. Both routines return a 1550 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 1551 ** memory to hold the resulting string. 1552 ** 1553 ** In sqlite3_snprintf() routine is similar to "snprintf()" from 1554 ** the standard C library. The result is written into the 1555 ** buffer supplied as the second parameter whose size is given by 1556 ** the first parameter. Note that the order of the 1557 ** first two parameters is reversed from snprintf(). This is an 1558 ** historical accident that cannot be fixed without breaking 1559 ** backwards compatibility. Note also that sqlite3_snprintf() 1560 ** returns a pointer to its buffer instead of the number of 1561 ** characters actually written into the buffer. We admit that 1562 ** the number of characters written would be a more useful return 1563 ** value but we cannot change the implementation of sqlite3_snprintf() 1564 ** now without breaking compatibility. 1565 ** 1566 ** As long as the buffer size is greater than zero, sqlite3_snprintf() 1567 ** guarantees that the buffer is always zero-terminated. The first 1568 ** parameter "n" is the total size of the buffer, including space for 1569 ** the zero terminator. So the longest string that can be completely 1570 ** written will be n-1 characters. 1571 ** 1572 ** These routines all implement some additional formatting 1573 ** options that are useful for constructing SQL statements. 1574 ** All of the usual printf() formatting options apply. In addition, there 1575 ** is are "%q", "%Q", and "%z" options. 1576 ** 1577 ** The %q option works like %s in that it substitutes a null-terminated 1578 ** string from the argument list. But %q also doubles every '\'' character. 1579 ** %q is designed for use inside a string literal. By doubling each '\'' 1580 ** character it escapes that character and allows it to be inserted into 1581 ** the string. 1582 ** 1583 ** For example, assume the string variable zText contains text as follows: 1584 ** 1585 ** <blockquote><pre> 1586 ** char *zText = "It's a happy day!"; 1587 ** </pre></blockquote> 1588 ** 1589 ** One can use this text in an SQL statement as follows: 1590 ** 1591 ** <blockquote><pre> 1592 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 1593 ** sqlite3_exec(db, zSQL, 0, 0, 0); 1594 ** sqlite3_free(zSQL); 1595 ** </pre></blockquote> 1596 ** 1597 ** Because the %q format string is used, the '\'' character in zText 1598 ** is escaped and the SQL generated is as follows: 1599 ** 1600 ** <blockquote><pre> 1601 ** INSERT INTO table1 VALUES('It''s a happy day!') 1602 ** </pre></blockquote> 1603 ** 1604 ** This is correct. Had we used %s instead of %q, the generated SQL 1605 ** would have looked like this: 1606 ** 1607 ** <blockquote><pre> 1608 ** INSERT INTO table1 VALUES('It's a happy day!'); 1609 ** </pre></blockquote> 1610 ** 1611 ** This second example is an SQL syntax error. As a general rule you should 1612 ** always use %q instead of %s when inserting text into a string literal. 1613 ** 1614 ** The %Q option works like %q except it also adds single quotes around 1615 ** the outside of the total string. Additionally, if the parameter in the 1616 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 1617 ** single quotes) in place of the %Q option. So, for example, one could say: 1618 ** 1619 ** <blockquote><pre> 1620 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 1621 ** sqlite3_exec(db, zSQL, 0, 0, 0); 1622 ** sqlite3_free(zSQL); 1623 ** </pre></blockquote> 1624 ** 1625 ** The code above will render a correct SQL statement in the zSQL 1626 ** variable even if the zText variable is a NULL pointer. 1627 ** 1628 ** The "%z" formatting option works exactly like "%s" with the 1629 ** addition that after the string has been read and copied into 1630 ** the result, [sqlite3_free()] is called on the input string. {END} 1631 ** 1632 ** Requirements: 1633 ** [H17403] [H17406] [H17407] 1634 */ 1635 char *sqlite3_mprintf(const char*,...); 1636 char *sqlite3_vmprintf(const char*, va_list); 1637 char *sqlite3_snprintf(int,char*,const char*, ...); 1638 1639 /* 1640 ** CAPI3REF: Memory Allocation Subsystem {H17300} <S20000> 1641 ** 1642 ** The SQLite core uses these three routines for all of its own 1643 ** internal memory allocation needs. "Core" in the previous sentence 1644 ** does not include operating-system specific VFS implementation. The 1645 ** Windows VFS uses native malloc() and free() for some operations. 1646 ** 1647 ** The sqlite3_malloc() routine returns a pointer to a block 1648 ** of memory at least N bytes in length, where N is the parameter. 1649 ** If sqlite3_malloc() is unable to obtain sufficient free 1650 ** memory, it returns a NULL pointer. If the parameter N to 1651 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 1652 ** a NULL pointer. 1653 ** 1654 ** Calling sqlite3_free() with a pointer previously returned 1655 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 1656 ** that it might be reused. The sqlite3_free() routine is 1657 ** a no-op if is called with a NULL pointer. Passing a NULL pointer 1658 ** to sqlite3_free() is harmless. After being freed, memory 1659 ** should neither be read nor written. Even reading previously freed 1660 ** memory might result in a segmentation fault or other severe error. 1661 ** Memory corruption, a segmentation fault, or other severe error 1662 ** might result if sqlite3_free() is called with a non-NULL pointer that 1663 ** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 1664 ** 1665 ** The sqlite3_realloc() interface attempts to resize a 1666 ** prior memory allocation to be at least N bytes, where N is the 1667 ** second parameter. The memory allocation to be resized is the first 1668 ** parameter. If the first parameter to sqlite3_realloc() 1669 ** is a NULL pointer then its behavior is identical to calling 1670 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 1671 ** If the second parameter to sqlite3_realloc() is zero or 1672 ** negative then the behavior is exactly the same as calling 1673 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 1674 ** sqlite3_realloc() returns a pointer to a memory allocation 1675 ** of at least N bytes in size or NULL if sufficient memory is unavailable. 1676 ** If M is the size of the prior allocation, then min(N,M) bytes 1677 ** of the prior allocation are copied into the beginning of buffer returned 1678 ** by sqlite3_realloc() and the prior allocation is freed. 1679 ** If sqlite3_realloc() returns NULL, then the prior allocation 1680 ** is not freed. 1681 ** 1682 ** The memory returned by sqlite3_malloc() and sqlite3_realloc() 1683 ** is always aligned to at least an 8 byte boundary. {END} 1684 ** 1685 ** The default implementation of the memory allocation subsystem uses 1686 ** the malloc(), realloc() and free() provided by the standard C library. 1687 ** {H17382} However, if SQLite is compiled with the 1688 ** SQLITE_MEMORY_SIZE=<i>NNN</i> C preprocessor macro (where <i>NNN</i> 1689 ** is an integer), then SQLite create a static array of at least 1690 ** <i>NNN</i> bytes in size and uses that array for all of its dynamic 1691 ** memory allocation needs. {END} Additional memory allocator options 1692 ** may be added in future releases. 1693 ** 1694 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define 1695 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 1696 ** implementation of these routines to be omitted. That capability 1697 ** is no longer provided. Only built-in memory allocators can be used. 1698 ** 1699 ** The Windows OS interface layer calls 1700 ** the system malloc() and free() directly when converting 1701 ** filenames between the UTF-8 encoding used by SQLite 1702 ** and whatever filename encoding is used by the particular Windows 1703 ** installation. Memory allocation errors are detected, but 1704 ** they are reported back as [SQLITE_CANTOPEN] or 1705 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 1706 ** 1707 ** Requirements: 1708 ** [H17303] [H17304] [H17305] [H17306] [H17310] [H17312] [H17315] [H17318] 1709 ** [H17321] [H17322] [H17323] 1710 ** 1711 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 1712 ** must be either NULL or else pointers obtained from a prior 1713 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 1714 ** not yet been released. 1715 ** 1716 ** The application must not read or write any part of 1717 ** a block of memory after it has been released using 1718 ** [sqlite3_free()] or [sqlite3_realloc()]. 1719 */ 1720 void *sqlite3_malloc(int); 1721 void *sqlite3_realloc(void*, int); 1722 void sqlite3_free(void*); 1723 1724 /* 1725 ** CAPI3REF: Memory Allocator Statistics {H17370} <S30210> 1726 ** 1727 ** SQLite provides these two interfaces for reporting on the status 1728 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 1729 ** routines, which form the built-in memory allocation subsystem. 1730 ** 1731 ** Requirements: 1732 ** [H17371] [H17373] [H17374] [H17375] 1733 */ 1734 sqlite3_int64 sqlite3_memory_used(void); 1735 sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 1736 1737 /* 1738 ** CAPI3REF: Pseudo-Random Number Generator {H17390} <S20000> 1739 ** 1740 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 1741 ** select random [ROWID | ROWIDs] when inserting new records into a table that 1742 ** already uses the largest possible [ROWID]. The PRNG is also used for 1743 ** the build-in random() and randomblob() SQL functions. This interface allows 1744 ** applications to access the same PRNG for other purposes. 1745 ** 1746 ** A call to this routine stores N bytes of randomness into buffer P. 1747 ** 1748 ** The first time this routine is invoked (either internally or by 1749 ** the application) the PRNG is seeded using randomness obtained 1750 ** from the xRandomness method of the default [sqlite3_vfs] object. 1751 ** On all subsequent invocations, the pseudo-randomness is generated 1752 ** internally and without recourse to the [sqlite3_vfs] xRandomness 1753 ** method. 1754 ** 1755 ** Requirements: 1756 ** [H17392] 1757 */ 1758 void sqlite3_randomness(int N, void *P); 1759 1760 /* 1761 ** CAPI3REF: Compile-Time Authorization Callbacks {H12500} <S70100> 1762 ** 1763 ** This routine registers a authorizer callback with a particular 1764 ** [database connection], supplied in the first argument. 1765 ** The authorizer callback is invoked as SQL statements are being compiled 1766 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 1767 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. At various 1768 ** points during the compilation process, as logic is being created 1769 ** to perform various actions, the authorizer callback is invoked to 1770 ** see if those actions are allowed. The authorizer callback should 1771 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 1772 ** specific action but allow the SQL statement to continue to be 1773 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 1774 ** rejected with an error. If the authorizer callback returns 1775 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 1776 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered 1777 ** the authorizer will fail with an error message. 1778 ** 1779 ** When the callback returns [SQLITE_OK], that means the operation 1780 ** requested is ok. When the callback returns [SQLITE_DENY], the 1781 ** [sqlite3_prepare_v2()] or equivalent call that triggered the 1782 ** authorizer will fail with an error message explaining that 1783 ** access is denied. If the authorizer code is [SQLITE_READ] 1784 ** and the callback returns [SQLITE_IGNORE] then the 1785 ** [prepared statement] statement is constructed to substitute 1786 ** a NULL value in place of the table column that would have 1787 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 1788 ** return can be used to deny an untrusted user access to individual 1789 ** columns of a table. 1790 ** 1791 ** The first parameter to the authorizer callback is a copy of the third 1792 ** parameter to the sqlite3_set_authorizer() interface. The second parameter 1793 ** to the callback is an integer [SQLITE_COPY | action code] that specifies 1794 ** the particular action to be authorized. The third through sixth parameters 1795 ** to the callback are zero-terminated strings that contain additional 1796 ** details about the action to be authorized. 1797 ** 1798 ** An authorizer is used when [sqlite3_prepare | preparing] 1799 ** SQL statements from an untrusted source, to ensure that the SQL statements 1800 ** do not try to access data they are not allowed to see, or that they do not 1801 ** try to execute malicious statements that damage the database. For 1802 ** example, an application may allow a user to enter arbitrary 1803 ** SQL queries for evaluation by a database. But the application does 1804 ** not want the user to be able to make arbitrary changes to the 1805 ** database. An authorizer could then be put in place while the 1806 ** user-entered SQL is being [sqlite3_prepare | prepared] that 1807 ** disallows everything except [SELECT] statements. 1808 ** 1809 ** Applications that need to process SQL from untrusted sources 1810 ** might also consider lowering resource limits using [sqlite3_limit()] 1811 ** and limiting database size using the [max_page_count] [PRAGMA] 1812 ** in addition to using an authorizer. 1813 ** 1814 ** Only a single authorizer can be in place on a database connection 1815 ** at a time. Each call to sqlite3_set_authorizer overrides the 1816 ** previous call. Disable the authorizer by installing a NULL callback. 1817 ** The authorizer is disabled by default. 1818 ** 1819 ** The authorizer callback must not do anything that will modify 1820 ** the database connection that invoked the authorizer callback. 1821 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 1822 ** database connections for the meaning of "modify" in this paragraph. 1823 ** 1824 ** When [sqlite3_prepare_v2()] is used to prepare a statement, the 1825 ** statement might be reprepared during [sqlite3_step()] due to a 1826 ** schema change. Hence, the application should ensure that the 1827 ** correct authorizer callback remains in place during the [sqlite3_step()]. 1828 ** 1829 ** Note that the authorizer callback is invoked only during 1830 ** [sqlite3_prepare()] or its variants. Authorization is not 1831 ** performed during statement evaluation in [sqlite3_step()]. 1832 ** 1833 ** Requirements: 1834 ** [H12501] [H12502] [H12503] [H12504] [H12505] [H12506] [H12507] [H12510] 1835 ** [H12511] [H12512] [H12520] [H12521] [H12522] 1836 */ 1837 int sqlite3_set_authorizer( 1838 sqlite3*, 1839 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 1840 void *pUserData 1841 ); 1842 1843 /* 1844 ** CAPI3REF: Authorizer Return Codes {H12590} <H12500> 1845 ** 1846 ** The [sqlite3_set_authorizer | authorizer callback function] must 1847 ** return either [SQLITE_OK] or one of these two constants in order 1848 ** to signal SQLite whether or not the action is permitted. See the 1849 ** [sqlite3_set_authorizer | authorizer documentation] for additional 1850 ** information. 1851 */ 1852 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 1853 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 1854 1855 /* 1856 ** CAPI3REF: Authorizer Action Codes {H12550} <H12500> 1857 ** 1858 ** The [sqlite3_set_authorizer()] interface registers a callback function 1859 ** that is invoked to authorize certain SQL statement actions. The 1860 ** second parameter to the callback is an integer code that specifies 1861 ** what action is being authorized. These are the integer action codes that 1862 ** the authorizer callback may be passed. 1863 ** 1864 ** These action code values signify what kind of operation is to be 1865 ** authorized. The 3rd and 4th parameters to the authorization 1866 ** callback function will be parameters or NULL depending on which of these 1867 ** codes is used as the second parameter. The 5th parameter to the 1868 ** authorizer callback is the name of the database ("main", "temp", 1869 ** etc.) if applicable. The 6th parameter to the authorizer callback 1870 ** is the name of the inner-most trigger or view that is responsible for 1871 ** the access attempt or NULL if this access attempt is directly from 1872 ** top-level SQL code. 1873 ** 1874 ** Requirements: 1875 ** [H12551] [H12552] [H12553] [H12554] 1876 */ 1877 /******************************************* 3rd ************ 4th ***********/ 1878 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 1879 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 1880 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 1881 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 1882 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 1883 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 1884 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 1885 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 1886 #define SQLITE_DELETE 9 /* Table Name NULL */ 1887 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 1888 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 1889 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 1890 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 1891 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 1892 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 1893 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 1894 #define SQLITE_DROP_VIEW 17 /* View Name NULL */ 1895 #define SQLITE_INSERT 18 /* Table Name NULL */ 1896 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 1897 #define SQLITE_READ 20 /* Table Name Column Name */ 1898 #define SQLITE_SELECT 21 /* NULL NULL */ 1899 #define SQLITE_TRANSACTION 22 /* Operation NULL */ 1900 #define SQLITE_UPDATE 23 /* Table Name Column Name */ 1901 #define SQLITE_ATTACH 24 /* Filename NULL */ 1902 #define SQLITE_DETACH 25 /* Database Name NULL */ 1903 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 1904 #define SQLITE_REINDEX 27 /* Index Name NULL */ 1905 #define SQLITE_ANALYZE 28 /* Table Name NULL */ 1906 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 1907 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 1908 #define SQLITE_FUNCTION 31 /* NULL Function Name */ 1909 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 1910 #define SQLITE_COPY 0 /* No longer used */ 1911 1912 /* 1913 ** CAPI3REF: Tracing And Profiling Functions {H12280} <S60400> 1914 ** EXPERIMENTAL 1915 ** 1916 ** These routines register callback functions that can be used for 1917 ** tracing and profiling the execution of SQL statements. 1918 ** 1919 ** The callback function registered by sqlite3_trace() is invoked at 1920 ** various times when an SQL statement is being run by [sqlite3_step()]. 1921 ** The callback returns a UTF-8 rendering of the SQL statement text 1922 ** as the statement first begins executing. Additional callbacks occur 1923 ** as each triggered subprogram is entered. The callbacks for triggers 1924 ** contain a UTF-8 SQL comment that identifies the trigger. 1925 ** 1926 ** The callback function registered by sqlite3_profile() is invoked 1927 ** as each SQL statement finishes. The profile callback contains 1928 ** the original statement text and an estimate of wall-clock time 1929 ** of how long that statement took to run. 1930 ** 1931 ** Requirements: 1932 ** [H12281] [H12282] [H12283] [H12284] [H12285] [H12287] [H12288] [H12289] 1933 ** [H12290] 1934 */ 1935 SQLITE_EXPERIMENTAL void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 1936 SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 1937 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 1938 1939 /* 1940 ** CAPI3REF: Query Progress Callbacks {H12910} <S60400> 1941 ** 1942 ** This routine configures a callback function - the 1943 ** progress callback - that is invoked periodically during long 1944 ** running calls to [sqlite3_exec()], [sqlite3_step()] and 1945 ** [sqlite3_get_table()]. An example use for this 1946 ** interface is to keep a GUI updated during a large query. 1947 ** 1948 ** If the progress callback returns non-zero, the operation is 1949 ** interrupted. This feature can be used to implement a 1950 ** "Cancel" button on a GUI progress dialog box. 1951 ** 1952 ** The progress handler must not do anything that will modify 1953 ** the database connection that invoked the progress handler. 1954 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 1955 ** database connections for the meaning of "modify" in this paragraph. 1956 ** 1957 ** Requirements: 1958 ** [H12911] [H12912] [H12913] [H12914] [H12915] [H12916] [H12917] [H12918] 1959 ** 1960 */ 1961 void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 1962 1963 /* 1964 ** CAPI3REF: Opening A New Database Connection {H12700} <S40200> 1965 ** 1966 ** These routines open an SQLite database file whose name is given by the 1967 ** filename argument. The filename argument is interpreted as UTF-8 for 1968 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 1969 ** order for sqlite3_open16(). A [database connection] handle is usually 1970 ** returned in *ppDb, even if an error occurs. The only exception is that 1971 ** if SQLite is unable to allocate memory to hold the [sqlite3] object, 1972 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 1973 ** object. If the database is opened (and/or created) successfully, then 1974 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned. The 1975 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 1976 ** an English language description of the error. 1977 ** 1978 ** The default encoding for the database will be UTF-8 if 1979 ** sqlite3_open() or sqlite3_open_v2() is called and 1980 ** UTF-16 in the native byte order if sqlite3_open16() is used. 1981 ** 1982 ** Whether or not an error occurs when it is opened, resources 1983 ** associated with the [database connection] handle should be released by 1984 ** passing it to [sqlite3_close()] when it is no longer required. 1985 ** 1986 ** The sqlite3_open_v2() interface works like sqlite3_open() 1987 ** except that it accepts two additional parameters for additional control 1988 ** over the new database connection. The flags parameter can take one of 1989 ** the following three values, optionally combined with the 1990 ** [SQLITE_OPEN_NOMUTEX] or [SQLITE_OPEN_FULLMUTEX] flags: 1991 ** 1992 ** <dl> 1993 ** <dt>[SQLITE_OPEN_READONLY]</dt> 1994 ** <dd>The database is opened in read-only mode. If the database does not 1995 ** already exist, an error is returned.</dd> 1996 ** 1997 ** <dt>[SQLITE_OPEN_READWRITE]</dt> 1998 ** <dd>The database is opened for reading and writing if possible, or reading 1999 ** only if the file is write protected by the operating system. In either 2000 ** case the database must already exist, otherwise an error is returned.</dd> 2001 ** 2002 ** <dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2003 ** <dd>The database is opened for reading and writing, and is creates it if 2004 ** it does not already exist. This is the behavior that is always used for 2005 ** sqlite3_open() and sqlite3_open16().</dd> 2006 ** </dl> 2007 ** 2008 ** If the 3rd parameter to sqlite3_open_v2() is not one of the 2009 ** combinations shown above or one of the combinations shown above combined 2010 ** with the [SQLITE_OPEN_NOMUTEX] or [SQLITE_OPEN_FULLMUTEX] flags, 2011 ** then the behavior is undefined. 2012 ** 2013 ** If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2014 ** opens in the multi-thread [threading mode] as long as the single-thread 2015 ** mode has not been set at compile-time or start-time. If the 2016 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2017 ** in the serialized [threading mode] unless single-thread was 2018 ** previously selected at compile-time or start-time. 2019 ** 2020 ** If the filename is ":memory:", then a private, temporary in-memory database 2021 ** is created for the connection. This in-memory database will vanish when 2022 ** the database connection is closed. Future versions of SQLite might 2023 ** make use of additional special filenames that begin with the ":" character. 2024 ** It is recommended that when a database filename actually does begin with 2025 ** a ":" character you should prefix the filename with a pathname such as 2026 ** "./" to avoid ambiguity. 2027 ** 2028 ** If the filename is an empty string, then a private, temporary 2029 ** on-disk database will be created. This private database will be 2030 ** automatically deleted as soon as the database connection is closed. 2031 ** 2032 ** The fourth parameter to sqlite3_open_v2() is the name of the 2033 ** [sqlite3_vfs] object that defines the operating system interface that 2034 ** the new database connection should use. If the fourth parameter is 2035 ** a NULL pointer then the default [sqlite3_vfs] object is used. 2036 ** 2037 ** <b>Note to Windows users:</b> The encoding used for the filename argument 2038 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2039 ** codepage is currently defined. Filenames containing international 2040 ** characters must be converted to UTF-8 prior to passing them into 2041 ** sqlite3_open() or sqlite3_open_v2(). 2042 ** 2043 ** Requirements: 2044 ** [H12701] [H12702] [H12703] [H12704] [H12706] [H12707] [H12709] [H12711] 2045 ** [H12712] [H12713] [H12714] [H12717] [H12719] [H12721] [H12723] 2046 */ 2047 int sqlite3_open( 2048 const char *filename, /* Database filename (UTF-8) */ 2049 sqlite3 **ppDb /* OUT: SQLite db handle */ 2050 ); 2051 int sqlite3_open16( 2052 const void *filename, /* Database filename (UTF-16) */ 2053 sqlite3 **ppDb /* OUT: SQLite db handle */ 2054 ); 2055 int sqlite3_open_v2( 2056 const char *filename, /* Database filename (UTF-8) */ 2057 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2058 int flags, /* Flags */ 2059 const char *zVfs /* Name of VFS module to use */ 2060 ); 2061 2062 /* 2063 ** CAPI3REF: Error Codes And Messages {H12800} <S60200> 2064 ** 2065 ** The sqlite3_errcode() interface returns the numeric [result code] or 2066 ** [extended result code] for the most recent failed sqlite3_* API call 2067 ** associated with a [database connection]. If a prior API call failed 2068 ** but the most recent API call succeeded, the return value from 2069 ** sqlite3_errcode() is undefined. The sqlite3_extended_errcode() 2070 ** interface is the same except that it always returns the 2071 ** [extended result code] even when extended result codes are 2072 ** disabled. 2073 ** 2074 ** The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2075 ** text that describes the error, as either UTF-8 or UTF-16 respectively. 2076 ** Memory to hold the error message string is managed internally. 2077 ** The application does not need to worry about freeing the result. 2078 ** However, the error string might be overwritten or deallocated by 2079 ** subsequent calls to other SQLite interface functions. 2080 ** 2081 ** When the serialized [threading mode] is in use, it might be the 2082 ** case that a second error occurs on a separate thread in between 2083 ** the time of the first error and the call to these interfaces. 2084 ** When that happens, the second error will be reported since these 2085 ** interfaces always report the most recent result. To avoid 2086 ** this, each thread can obtain exclusive use of the [database connection] D 2087 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2088 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2089 ** all calls to the interfaces listed here are completed. 2090 ** 2091 ** If an interface fails with SQLITE_MISUSE, that means the interface 2092 ** was invoked incorrectly by the application. In that case, the 2093 ** error code and message may or may not be set. 2094 ** 2095 ** Requirements: 2096 ** [H12801] [H12802] [H12803] [H12807] [H12808] [H12809] 2097 */ 2098 int sqlite3_errcode(sqlite3 *db); 2099 int sqlite3_extended_errcode(sqlite3 *db); 2100 const char *sqlite3_errmsg(sqlite3*); 2101 const void *sqlite3_errmsg16(sqlite3*); 2102 2103 /* 2104 ** CAPI3REF: SQL Statement Object {H13000} <H13010> 2105 ** KEYWORDS: {prepared statement} {prepared statements} 2106 ** 2107 ** An instance of this object represents a single SQL statement. 2108 ** This object is variously known as a "prepared statement" or a 2109 ** "compiled SQL statement" or simply as a "statement". 2110 ** 2111 ** The life of a statement object goes something like this: 2112 ** 2113 ** <ol> 2114 ** <li> Create the object using [sqlite3_prepare_v2()] or a related 2115 ** function. 2116 ** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2117 ** interfaces. 2118 ** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2119 ** <li> Reset the statement using [sqlite3_reset()] then go back 2120 ** to step 2. Do this zero or more times. 2121 ** <li> Destroy the object using [sqlite3_finalize()]. 2122 ** </ol> 2123 ** 2124 ** Refer to documentation on individual methods above for additional 2125 ** information. 2126 */ 2127 typedef struct sqlite3_stmt sqlite3_stmt; 2128 2129 /* 2130 ** CAPI3REF: Run-time Limits {H12760} <S20600> 2131 ** 2132 ** This interface allows the size of various constructs to be limited 2133 ** on a connection by connection basis. The first parameter is the 2134 ** [database connection] whose limit is to be set or queried. The 2135 ** second parameter is one of the [limit categories] that define a 2136 ** class of constructs to be size limited. The third parameter is the 2137 ** new limit for that construct. The function returns the old limit. 2138 ** 2139 ** If the new limit is a negative number, the limit is unchanged. 2140 ** For the limit category of SQLITE_LIMIT_XYZ there is a 2141 ** [limits | hard upper bound] 2142 ** set by a compile-time C preprocessor macro named 2143 ** [limits | SQLITE_MAX_XYZ]. 2144 ** (The "_LIMIT_" in the name is changed to "_MAX_".) 2145 ** Attempts to increase a limit above its hard upper bound are 2146 ** silently truncated to the hard upper limit. 2147 ** 2148 ** Run time limits are intended for use in applications that manage 2149 ** both their own internal database and also databases that are controlled 2150 ** by untrusted external sources. An example application might be a 2151 ** web browser that has its own databases for storing history and 2152 ** separate databases controlled by JavaScript applications downloaded 2153 ** off the Internet. The internal databases can be given the 2154 ** large, default limits. Databases managed by external sources can 2155 ** be given much smaller limits designed to prevent a denial of service 2156 ** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2157 ** interface to further control untrusted SQL. The size of the database 2158 ** created by an untrusted script can be contained using the 2159 ** [max_page_count] [PRAGMA]. 2160 ** 2161 ** New run-time limit categories may be added in future releases. 2162 ** 2163 ** Requirements: 2164 ** [H12762] [H12766] [H12769] 2165 */ 2166 int sqlite3_limit(sqlite3*, int id, int newVal); 2167 2168 /* 2169 ** CAPI3REF: Run-Time Limit Categories {H12790} <H12760> 2170 ** KEYWORDS: {limit category} {limit categories} 2171 ** 2172 ** These constants define various performance limits 2173 ** that can be lowered at run-time using [sqlite3_limit()]. 2174 ** The synopsis of the meanings of the various limits is shown below. 2175 ** Additional information is available at [limits | Limits in SQLite]. 2176 ** 2177 ** <dl> 2178 ** <dt>SQLITE_LIMIT_LENGTH</dt> 2179 ** <dd>The maximum size of any string or BLOB or table row.<dd> 2180 ** 2181 ** <dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2182 ** <dd>The maximum length of an SQL statement.</dd> 2183 ** 2184 ** <dt>SQLITE_LIMIT_COLUMN</dt> 2185 ** <dd>The maximum number of columns in a table definition or in the 2186 ** result set of a [SELECT] or the maximum number of columns in an index 2187 ** or in an ORDER BY or GROUP BY clause.</dd> 2188 ** 2189 ** <dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2190 ** <dd>The maximum depth of the parse tree on any expression.</dd> 2191 ** 2192 ** <dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2193 ** <dd>The maximum number of terms in a compound SELECT statement.</dd> 2194 ** 2195 ** <dt>SQLITE_LIMIT_VDBE_OP</dt> 2196 ** <dd>The maximum number of instructions in a virtual machine program 2197 ** used to implement an SQL statement.</dd> 2198 ** 2199 ** <dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2200 ** <dd>The maximum number of arguments on a function.</dd> 2201 ** 2202 ** <dt>SQLITE_LIMIT_ATTACHED</dt> 2203 ** <dd>The maximum number of [ATTACH | attached databases].</dd> 2204 ** 2205 ** <dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2206 ** <dd>The maximum length of the pattern argument to the [LIKE] or 2207 ** [GLOB] operators.</dd> 2208 ** 2209 ** <dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2210 ** <dd>The maximum number of variables in an SQL statement that can 2211 ** be bound.</dd> 2212 ** </dl> 2213 */ 2214 #define SQLITE_LIMIT_LENGTH 0 2215 #define SQLITE_LIMIT_SQL_LENGTH 1 2216 #define SQLITE_LIMIT_COLUMN 2 2217 #define SQLITE_LIMIT_EXPR_DEPTH 3 2218 #define SQLITE_LIMIT_COMPOUND_SELECT 4 2219 #define SQLITE_LIMIT_VDBE_OP 5 2220 #define SQLITE_LIMIT_FUNCTION_ARG 6 2221 #define SQLITE_LIMIT_ATTACHED 7 2222 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2223 #define SQLITE_LIMIT_VARIABLE_NUMBER 9 2224 2225 /* 2226 ** CAPI3REF: Compiling An SQL Statement {H13010} <S10000> 2227 ** KEYWORDS: {SQL statement compiler} 2228 ** 2229 ** To execute an SQL query, it must first be compiled into a byte-code 2230 ** program using one of these routines. 2231 ** 2232 ** The first argument, "db", is a [database connection] obtained from a 2233 ** prior call to [sqlite3_open()], [sqlite3_open_v2()] or [sqlite3_open16()]. 2234 ** 2235 ** The second argument, "zSql", is the statement to be compiled, encoded 2236 ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2237 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2238 ** use UTF-16. 2239 ** 2240 ** If the nByte argument is less than zero, then zSql is read up to the 2241 ** first zero terminator. If nByte is non-negative, then it is the maximum 2242 ** number of bytes read from zSql. When nByte is non-negative, the 2243 ** zSql string ends at either the first '\000' or '\u0000' character or 2244 ** the nByte-th byte, whichever comes first. If the caller knows 2245 ** that the supplied string is nul-terminated, then there is a small 2246 ** performance advantage to be gained by passing an nByte parameter that 2247 ** is equal to the number of bytes in the input string <i>including</i> 2248 ** the nul-terminator bytes. 2249 ** 2250 ** *pzTail is made to point to the first byte past the end of the 2251 ** first SQL statement in zSql. These routines only compile the first 2252 ** statement in zSql, so *pzTail is left pointing to what remains 2253 ** uncompiled. 2254 ** 2255 ** *ppStmt is left pointing to a compiled [prepared statement] that can be 2256 ** executed using [sqlite3_step()]. If there is an error, *ppStmt is set 2257 ** to NULL. If the input text contains no SQL (if the input is an empty 2258 ** string or a comment) then *ppStmt is set to NULL. 2259 ** {A13018} The calling procedure is responsible for deleting the compiled 2260 ** SQL statement using [sqlite3_finalize()] after it has finished with it. 2261 ** 2262 ** On success, [SQLITE_OK] is returned, otherwise an [error code] is returned. 2263 ** 2264 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2265 ** recommended for all new programs. The two older interfaces are retained 2266 ** for backwards compatibility, but their use is discouraged. 2267 ** In the "v2" interfaces, the prepared statement 2268 ** that is returned (the [sqlite3_stmt] object) contains a copy of the 2269 ** original SQL text. This causes the [sqlite3_step()] interface to 2270 ** behave a differently in two ways: 2271 ** 2272 ** <ol> 2273 ** <li> 2274 ** If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2275 ** always used to do, [sqlite3_step()] will automatically recompile the SQL 2276 ** statement and try to run it again. If the schema has changed in 2277 ** a way that makes the statement no longer valid, [sqlite3_step()] will still 2278 ** return [SQLITE_SCHEMA]. But unlike the legacy behavior, [SQLITE_SCHEMA] is 2279 ** now a fatal error. Calling [sqlite3_prepare_v2()] again will not make the 2280 ** error go away. Note: use [sqlite3_errmsg()] to find the text 2281 ** of the parsing error that results in an [SQLITE_SCHEMA] return. 2282 ** </li> 2283 ** 2284 ** <li> 2285 ** When an error occurs, [sqlite3_step()] will return one of the detailed 2286 ** [error codes] or [extended error codes]. The legacy behavior was that 2287 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2288 ** and you would have to make a second call to [sqlite3_reset()] in order 2289 ** to find the underlying cause of the problem. With the "v2" prepare 2290 ** interfaces, the underlying reason for the error is returned immediately. 2291 ** </li> 2292 ** </ol> 2293 ** 2294 ** Requirements: 2295 ** [H13011] [H13012] [H13013] [H13014] [H13015] [H13016] [H13019] [H13021] 2296 ** 2297 */ 2298 int sqlite3_prepare( 2299 sqlite3 *db, /* Database handle */ 2300 const char *zSql, /* SQL statement, UTF-8 encoded */ 2301 int nByte, /* Maximum length of zSql in bytes. */ 2302 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2303 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2304 ); 2305 int sqlite3_prepare_v2( 2306 sqlite3 *db, /* Database handle */ 2307 const char *zSql, /* SQL statement, UTF-8 encoded */ 2308 int nByte, /* Maximum length of zSql in bytes. */ 2309 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2310 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2311 ); 2312 int sqlite3_prepare16( 2313 sqlite3 *db, /* Database handle */ 2314 const void *zSql, /* SQL statement, UTF-16 encoded */ 2315 int nByte, /* Maximum length of zSql in bytes. */ 2316 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2317 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2318 ); 2319 int sqlite3_prepare16_v2( 2320 sqlite3 *db, /* Database handle */ 2321 const void *zSql, /* SQL statement, UTF-16 encoded */ 2322 int nByte, /* Maximum length of zSql in bytes. */ 2323 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2324 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2325 ); 2326 2327 /* 2328 ** CAPI3REF: Retrieving Statement SQL {H13100} <H13000> 2329 ** 2330 ** This interface can be used to retrieve a saved copy of the original 2331 ** SQL text used to create a [prepared statement] if that statement was 2332 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2333 ** 2334 ** Requirements: 2335 ** [H13101] [H13102] [H13103] 2336 */ 2337 const char *sqlite3_sql(sqlite3_stmt *pStmt); 2338 2339 /* 2340 ** CAPI3REF: Dynamically Typed Value Object {H15000} <S20200> 2341 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 2342 ** 2343 ** SQLite uses the sqlite3_value object to represent all values 2344 ** that can be stored in a database table. SQLite uses dynamic typing 2345 ** for the values it stores. Values stored in sqlite3_value objects 2346 ** can be integers, floating point values, strings, BLOBs, or NULL. 2347 ** 2348 ** An sqlite3_value object may be either "protected" or "unprotected". 2349 ** Some interfaces require a protected sqlite3_value. Other interfaces 2350 ** will accept either a protected or an unprotected sqlite3_value. 2351 ** Every interface that accepts sqlite3_value arguments specifies 2352 ** whether or not it requires a protected sqlite3_value. 2353 ** 2354 ** The terms "protected" and "unprotected" refer to whether or not 2355 ** a mutex is held. A internal mutex is held for a protected 2356 ** sqlite3_value object but no mutex is held for an unprotected 2357 ** sqlite3_value object. If SQLite is compiled to be single-threaded 2358 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 2359 ** or if SQLite is run in one of reduced mutex modes 2360 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 2361 ** then there is no distinction between protected and unprotected 2362 ** sqlite3_value objects and they can be used interchangeably. However, 2363 ** for maximum code portability it is recommended that applications 2364 ** still make the distinction between between protected and unprotected 2365 ** sqlite3_value objects even when not strictly required. 2366 ** 2367 ** The sqlite3_value objects that are passed as parameters into the 2368 ** implementation of [application-defined SQL functions] are protected. 2369 ** The sqlite3_value object returned by 2370 ** [sqlite3_column_value()] is unprotected. 2371 ** Unprotected sqlite3_value objects may only be used with 2372 ** [sqlite3_result_value()] and [sqlite3_bind_value()]. 2373 ** The [sqlite3_value_blob | sqlite3_value_type()] family of 2374 ** interfaces require protected sqlite3_value objects. 2375 */ 2376 typedef struct Mem sqlite3_value; 2377 2378 /* 2379 ** CAPI3REF: SQL Function Context Object {H16001} <S20200> 2380 ** 2381 ** The context in which an SQL function executes is stored in an 2382 ** sqlite3_context object. A pointer to an sqlite3_context object 2383 ** is always first parameter to [application-defined SQL functions]. 2384 ** The application-defined SQL function implementation will pass this 2385 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 2386 ** [sqlite3_aggregate_context()], [sqlite3_user_data()], 2387 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 2388 ** and/or [sqlite3_set_auxdata()]. 2389 */ 2390 typedef struct sqlite3_context sqlite3_context; 2391 2392 /* 2393 ** CAPI3REF: Binding Values To Prepared Statements {H13500} <S70300> 2394 ** KEYWORDS: {host parameter} {host parameters} {host parameter name} 2395 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 2396 ** 2397 ** In the SQL strings input to [sqlite3_prepare_v2()] and its variants, 2398 ** literals may be replaced by a [parameter] in one of these forms: 2399 ** 2400 ** <ul> 2401 ** <li> ? 2402 ** <li> ?NNN 2403 ** <li> :VVV 2404 ** <li> @VVV 2405 ** <li> $VVV 2406 ** </ul> 2407 ** 2408 ** In the parameter forms shown above NNN is an integer literal, 2409 ** and VVV is an alpha-numeric parameter name. The values of these 2410 ** parameters (also called "host parameter names" or "SQL parameters") 2411 ** can be set using the sqlite3_bind_*() routines defined here. 2412 ** 2413 ** The first argument to the sqlite3_bind_*() routines is always 2414 ** a pointer to the [sqlite3_stmt] object returned from 2415 ** [sqlite3_prepare_v2()] or its variants. 2416 ** 2417 ** The second argument is the index of the SQL parameter to be set. 2418 ** The leftmost SQL parameter has an index of 1. When the same named 2419 ** SQL parameter is used more than once, second and subsequent 2420 ** occurrences have the same index as the first occurrence. 2421 ** The index for named parameters can be looked up using the 2422 ** [sqlite3_bind_parameter_index()] API if desired. The index 2423 ** for "?NNN" parameters is the value of NNN. 2424 ** The NNN value must be between 1 and the [sqlite3_limit()] 2425 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 2426 ** 2427 ** The third argument is the value to bind to the parameter. 2428 ** 2429 ** In those routines that have a fourth argument, its value is the 2430 ** number of bytes in the parameter. To be clear: the value is the 2431 ** number of <u>bytes</u> in the value, not the number of characters. 2432 ** If the fourth parameter is negative, the length of the string is 2433 ** the number of bytes up to the first zero terminator. 2434 ** 2435 ** The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 2436 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 2437 ** string after SQLite has finished with it. If the fifth argument is 2438 ** the special value [SQLITE_STATIC], then SQLite assumes that the 2439 ** information is in static, unmanaged space and does not need to be freed. 2440 ** If the fifth argument has the value [SQLITE_TRANSIENT], then 2441 ** SQLite makes its own private copy of the data immediately, before 2442 ** the sqlite3_bind_*() routine returns. 2443 ** 2444 ** The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 2445 ** is filled with zeroes. A zeroblob uses a fixed amount of memory 2446 ** (just an integer to hold its size) while it is being processed. 2447 ** Zeroblobs are intended to serve as placeholders for BLOBs whose 2448 ** content is later written using 2449 ** [sqlite3_blob_open | incremental BLOB I/O] routines. 2450 ** A negative value for the zeroblob results in a zero-length BLOB. 2451 ** 2452 ** The sqlite3_bind_*() routines must be called after 2453 ** [sqlite3_prepare_v2()] (and its variants) or [sqlite3_reset()] and 2454 ** before [sqlite3_step()]. 2455 ** Bindings are not cleared by the [sqlite3_reset()] routine. 2456 ** Unbound parameters are interpreted as NULL. 2457 ** 2458 ** These routines return [SQLITE_OK] on success or an error code if 2459 ** anything goes wrong. [SQLITE_RANGE] is returned if the parameter 2460 ** index is out of range. [SQLITE_NOMEM] is returned if malloc() fails. 2461 ** [SQLITE_MISUSE] might be returned if these routines are called on a 2462 ** virtual machine that is the wrong state or which has already been finalized. 2463 ** Detection of misuse is unreliable. Applications should not depend 2464 ** on SQLITE_MISUSE returns. SQLITE_MISUSE is intended to indicate a 2465 ** a logic error in the application. Future versions of SQLite might 2466 ** panic rather than return SQLITE_MISUSE. 2467 ** 2468 ** See also: [sqlite3_bind_parameter_count()], 2469 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 2470 ** 2471 ** Requirements: 2472 ** [H13506] [H13509] [H13512] [H13515] [H13518] [H13521] [H13524] [H13527] 2473 ** [H13530] [H13533] [H13536] [H13539] [H13542] [H13545] [H13548] [H13551] 2474 ** 2475 */ 2476 int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 2477 int sqlite3_bind_double(sqlite3_stmt*, int, double); 2478 int sqlite3_bind_int(sqlite3_stmt*, int, int); 2479 int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 2480 int sqlite3_bind_null(sqlite3_stmt*, int); 2481 int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 2482 int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 2483 int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 2484 int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 2485 2486 /* 2487 ** CAPI3REF: Number Of SQL Parameters {H13600} <S70300> 2488 ** 2489 ** This routine can be used to find the number of [SQL parameters] 2490 ** in a [prepared statement]. SQL parameters are tokens of the 2491 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 2492 ** placeholders for values that are [sqlite3_bind_blob | bound] 2493 ** to the parameters at a later time. 2494 ** 2495 ** This routine actually returns the index of the largest (rightmost) 2496 ** parameter. For all forms except ?NNN, this will correspond to the 2497 ** number of unique parameters. If parameters of the ?NNN are used, 2498 ** there may be gaps in the list. 2499 ** 2500 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 2501 ** [sqlite3_bind_parameter_name()], and 2502 ** [sqlite3_bind_parameter_index()]. 2503 ** 2504 ** Requirements: 2505 ** [H13601] 2506 */ 2507 int sqlite3_bind_parameter_count(sqlite3_stmt*); 2508 2509 /* 2510 ** CAPI3REF: Name Of A Host Parameter {H13620} <S70300> 2511 ** 2512 ** This routine returns a pointer to the name of the n-th 2513 ** [SQL parameter] in a [prepared statement]. 2514 ** SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 2515 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 2516 ** respectively. 2517 ** In other words, the initial ":" or "$" or "@" or "?" 2518 ** is included as part of the name. 2519 ** Parameters of the form "?" without a following integer have no name 2520 ** and are also referred to as "anonymous parameters". 2521 ** 2522 ** The first host parameter has an index of 1, not 0. 2523 ** 2524 ** If the value n is out of range or if the n-th parameter is 2525 ** nameless, then NULL is returned. The returned string is 2526 ** always in UTF-8 encoding even if the named parameter was 2527 ** originally specified as UTF-16 in [sqlite3_prepare16()] or 2528 ** [sqlite3_prepare16_v2()]. 2529 ** 2530 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 2531 ** [sqlite3_bind_parameter_count()], and 2532 ** [sqlite3_bind_parameter_index()]. 2533 ** 2534 ** Requirements: 2535 ** [H13621] 2536 */ 2537 const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 2538 2539 /* 2540 ** CAPI3REF: Index Of A Parameter With A Given Name {H13640} <S70300> 2541 ** 2542 ** Return the index of an SQL parameter given its name. The 2543 ** index value returned is suitable for use as the second 2544 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. A zero 2545 ** is returned if no matching parameter is found. The parameter 2546 ** name must be given in UTF-8 even if the original statement 2547 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 2548 ** 2549 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 2550 ** [sqlite3_bind_parameter_count()], and 2551 ** [sqlite3_bind_parameter_index()]. 2552 ** 2553 ** Requirements: 2554 ** [H13641] 2555 */ 2556 int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 2557 2558 /* 2559 ** CAPI3REF: Reset All Bindings On A Prepared Statement {H13660} <S70300> 2560 ** 2561 ** Contrary to the intuition of many, [sqlite3_reset()] does not reset 2562 ** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 2563 ** Use this routine to reset all host parameters to NULL. 2564 ** 2565 ** Requirements: 2566 ** [H13661] 2567 */ 2568 int sqlite3_clear_bindings(sqlite3_stmt*); 2569 2570 /* 2571 ** CAPI3REF: Number Of Columns In A Result Set {H13710} <S10700> 2572 ** 2573 ** Return the number of columns in the result set returned by the 2574 ** [prepared statement]. This routine returns 0 if pStmt is an SQL 2575 ** statement that does not return data (for example an [UPDATE]). 2576 ** 2577 ** Requirements: 2578 ** [H13711] 2579 */ 2580 int sqlite3_column_count(sqlite3_stmt *pStmt); 2581 2582 /* 2583 ** CAPI3REF: Column Names In A Result Set {H13720} <S10700> 2584 ** 2585 ** These routines return the name assigned to a particular column 2586 ** in the result set of a [SELECT] statement. The sqlite3_column_name() 2587 ** interface returns a pointer to a zero-terminated UTF-8 string 2588 ** and sqlite3_column_name16() returns a pointer to a zero-terminated 2589 ** UTF-16 string. The first parameter is the [prepared statement] 2590 ** that implements the [SELECT] statement. The second parameter is the 2591 ** column number. The leftmost column is number 0. 2592 ** 2593 ** The returned string pointer is valid until either the [prepared statement] 2594 ** is destroyed by [sqlite3_finalize()] or until the next call to 2595 ** sqlite3_column_name() or sqlite3_column_name16() on the same column. 2596 ** 2597 ** If sqlite3_malloc() fails during the processing of either routine 2598 ** (for example during a conversion from UTF-8 to UTF-16) then a 2599 ** NULL pointer is returned. 2600 ** 2601 ** The name of a result column is the value of the "AS" clause for 2602 ** that column, if there is an AS clause. If there is no AS clause 2603 ** then the name of the column is unspecified and may change from 2604 ** one release of SQLite to the next. 2605 ** 2606 ** Requirements: 2607 ** [H13721] [H13723] [H13724] [H13725] [H13726] [H13727] 2608 */ 2609 const char *sqlite3_column_name(sqlite3_stmt*, int N); 2610 const void *sqlite3_column_name16(sqlite3_stmt*, int N); 2611 2612 /* 2613 ** CAPI3REF: Source Of Data In A Query Result {H13740} <S10700> 2614 ** 2615 ** These routines provide a means to determine what column of what 2616 ** table in which database a result of a [SELECT] statement comes from. 2617 ** The name of the database or table or column can be returned as 2618 ** either a UTF-8 or UTF-16 string. The _database_ routines return 2619 ** the database name, the _table_ routines return the table name, and 2620 ** the origin_ routines return the column name. 2621 ** The returned string is valid until the [prepared statement] is destroyed 2622 ** using [sqlite3_finalize()] or until the same information is requested 2623 ** again in a different encoding. 2624 ** 2625 ** The names returned are the original un-aliased names of the 2626 ** database, table, and column. 2627 ** 2628 ** The first argument to the following calls is a [prepared statement]. 2629 ** These functions return information about the Nth column returned by 2630 ** the statement, where N is the second function argument. 2631 ** 2632 ** If the Nth column returned by the statement is an expression or 2633 ** subquery and is not a column value, then all of these functions return 2634 ** NULL. These routine might also return NULL if a memory allocation error 2635 ** occurs. Otherwise, they return the name of the attached database, table 2636 ** and column that query result column was extracted from. 2637 ** 2638 ** As with all other SQLite APIs, those postfixed with "16" return 2639 ** UTF-16 encoded strings, the other functions return UTF-8. {END} 2640 ** 2641 ** These APIs are only available if the library was compiled with the 2642 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 2643 ** 2644 ** {A13751} 2645 ** If two or more threads call one or more of these routines against the same 2646 ** prepared statement and column at the same time then the results are 2647 ** undefined. 2648 ** 2649 ** Requirements: 2650 ** [H13741] [H13742] [H13743] [H13744] [H13745] [H13746] [H13748] 2651 ** 2652 ** If two or more threads call one or more 2653 ** [sqlite3_column_database_name | column metadata interfaces] 2654 ** for the same [prepared statement] and result column 2655 ** at the same time then the results are undefined. 2656 */ 2657 const char *sqlite3_column_database_name(sqlite3_stmt*,int); 2658 const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 2659 const char *sqlite3_column_table_name(sqlite3_stmt*,int); 2660 const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 2661 const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 2662 const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 2663 2664 /* 2665 ** CAPI3REF: Declared Datatype Of A Query Result {H13760} <S10700> 2666 ** 2667 ** The first parameter is a [prepared statement]. 2668 ** If this statement is a [SELECT] statement and the Nth column of the 2669 ** returned result set of that [SELECT] is a table column (not an 2670 ** expression or subquery) then the declared type of the table 2671 ** column is returned. If the Nth column of the result set is an 2672 ** expression or subquery, then a NULL pointer is returned. 2673 ** The returned string is always UTF-8 encoded. {END} 2674 ** 2675 ** For example, given the database schema: 2676 ** 2677 ** CREATE TABLE t1(c1 VARIANT); 2678 ** 2679 ** and the following statement to be compiled: 2680 ** 2681 ** SELECT c1 + 1, c1 FROM t1; 2682 ** 2683 ** this routine would return the string "VARIANT" for the second result 2684 ** column (i==1), and a NULL pointer for the first result column (i==0). 2685 ** 2686 ** SQLite uses dynamic run-time typing. So just because a column 2687 ** is declared to contain a particular type does not mean that the 2688 ** data stored in that column is of the declared type. SQLite is 2689 ** strongly typed, but the typing is dynamic not static. Type 2690 ** is associated with individual values, not with the containers 2691 ** used to hold those values. 2692 ** 2693 ** Requirements: 2694 ** [H13761] [H13762] [H13763] 2695 */ 2696 const char *sqlite3_column_decltype(sqlite3_stmt*,int); 2697 const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 2698 2699 /* 2700 ** CAPI3REF: Evaluate An SQL Statement {H13200} <S10000> 2701 ** 2702 ** After a [prepared statement] has been prepared using either 2703 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 2704 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 2705 ** must be called one or more times to evaluate the statement. 2706 ** 2707 ** The details of the behavior of the sqlite3_step() interface depend 2708 ** on whether the statement was prepared using the newer "v2" interface 2709 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 2710 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 2711 ** new "v2" interface is recommended for new applications but the legacy 2712 ** interface will continue to be supported. 2713 ** 2714 ** In the legacy interface, the return value will be either [SQLITE_BUSY], 2715 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 2716 ** With the "v2" interface, any of the other [result codes] or 2717 ** [extended result codes] might be returned as well. 2718 ** 2719 ** [SQLITE_BUSY] means that the database engine was unable to acquire the 2720 ** database locks it needs to do its job. If the statement is a [COMMIT] 2721 ** or occurs outside of an explicit transaction, then you can retry the 2722 ** statement. If the statement is not a [COMMIT] and occurs within a 2723 ** explicit transaction then you should rollback the transaction before 2724 ** continuing. 2725 ** 2726 ** [SQLITE_DONE] means that the statement has finished executing 2727 ** successfully. sqlite3_step() should not be called again on this virtual 2728 ** machine without first calling [sqlite3_reset()] to reset the virtual 2729 ** machine back to its initial state. 2730 ** 2731 ** If the SQL statement being executed returns any data, then [SQLITE_ROW] 2732 ** is returned each time a new row of data is ready for processing by the 2733 ** caller. The values may be accessed using the [column access functions]. 2734 ** sqlite3_step() is called again to retrieve the next row of data. 2735 ** 2736 ** [SQLITE_ERROR] means that a run-time error (such as a constraint 2737 ** violation) has occurred. sqlite3_step() should not be called again on 2738 ** the VM. More information may be found by calling [sqlite3_errmsg()]. 2739 ** With the legacy interface, a more specific error code (for example, 2740 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 2741 ** can be obtained by calling [sqlite3_reset()] on the 2742 ** [prepared statement]. In the "v2" interface, 2743 ** the more specific error code is returned directly by sqlite3_step(). 2744 ** 2745 ** [SQLITE_MISUSE] means that the this routine was called inappropriately. 2746 ** Perhaps it was called on a [prepared statement] that has 2747 ** already been [sqlite3_finalize | finalized] or on one that had 2748 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 2749 ** be the case that the same database connection is being used by two or 2750 ** more threads at the same moment in time. 2751 ** 2752 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 2753 ** API always returns a generic error code, [SQLITE_ERROR], following any 2754 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 2755 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 2756 ** specific [error codes] that better describes the error. 2757 ** We admit that this is a goofy design. The problem has been fixed 2758 ** with the "v2" interface. If you prepare all of your SQL statements 2759 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 2760 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 2761 ** then the more specific [error codes] are returned directly 2762 ** by sqlite3_step(). The use of the "v2" interface is recommended. 2763 ** 2764 ** Requirements: 2765 ** [H13202] [H15304] [H15306] [H15308] [H15310] 2766 */ 2767 int sqlite3_step(sqlite3_stmt*); 2768 2769 /* 2770 ** CAPI3REF: Number of columns in a result set {H13770} <S10700> 2771 ** 2772 ** Returns the number of values in the current row of the result set. 2773 ** 2774 ** Requirements: 2775 ** [H13771] [H13772] 2776 */ 2777 int sqlite3_data_count(sqlite3_stmt *pStmt); 2778 2779 /* 2780 ** CAPI3REF: Fundamental Datatypes {H10265} <S10110><S10120> 2781 ** KEYWORDS: SQLITE_TEXT 2782 ** 2783 ** {H10266} Every value in SQLite has one of five fundamental datatypes: 2784 ** 2785 ** <ul> 2786 ** <li> 64-bit signed integer 2787 ** <li> 64-bit IEEE floating point number 2788 ** <li> string 2789 ** <li> BLOB 2790 ** <li> NULL 2791 ** </ul> {END} 2792 ** 2793 ** These constants are codes for each of those types. 2794 ** 2795 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2 2796 ** for a completely different meaning. Software that links against both 2797 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 2798 ** SQLITE_TEXT. 2799 */ 2800 #define SQLITE_INTEGER 1 2801 #define SQLITE_FLOAT 2 2802 #define SQLITE_BLOB 4 2803 #define SQLITE_NULL 5 2804 #ifdef SQLITE_TEXT 2805 # undef SQLITE_TEXT 2806 #else 2807 # define SQLITE_TEXT 3 2808 #endif 2809 #define SQLITE3_TEXT 3 2810 2811 /* 2812 ** CAPI3REF: Result Values From A Query {H13800} <S10700> 2813 ** KEYWORDS: {column access functions} 2814 ** 2815 ** These routines form the "result set query" interface. 2816 ** 2817 ** These routines return information about a single column of the current 2818 ** result row of a query. In every case the first argument is a pointer 2819 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 2820 ** that was returned from [sqlite3_prepare_v2()] or one of its variants) 2821 ** and the second argument is the index of the column for which information 2822 ** should be returned. The leftmost column of the result set has the index 0. 2823 ** 2824 ** If the SQL statement does not currently point to a valid row, or if the 2825 ** column index is out of range, the result is undefined. 2826 ** These routines may only be called when the most recent call to 2827 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither 2828 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 2829 ** If any of these routines are called after [sqlite3_reset()] or 2830 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned 2831 ** something other than [SQLITE_ROW], the results are undefined. 2832 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 2833 ** are called from a different thread while any of these routines 2834 ** are pending, then the results are undefined. 2835 ** 2836 ** The sqlite3_column_type() routine returns the 2837 ** [SQLITE_INTEGER | datatype code] for the initial data type 2838 ** of the result column. The returned value is one of [SQLITE_INTEGER], 2839 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 2840 ** returned by sqlite3_column_type() is only meaningful if no type 2841 ** conversions have occurred as described below. After a type conversion, 2842 ** the value returned by sqlite3_column_type() is undefined. Future 2843 ** versions of SQLite may change the behavior of sqlite3_column_type() 2844 ** following a type conversion. 2845 ** 2846 ** If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 2847 ** routine returns the number of bytes in that BLOB or string. 2848 ** If the result is a UTF-16 string, then sqlite3_column_bytes() converts 2849 ** the string to UTF-8 and then returns the number of bytes. 2850 ** If the result is a numeric value then sqlite3_column_bytes() uses 2851 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 2852 ** the number of bytes in that string. 2853 ** The value returned does not include the zero terminator at the end 2854 ** of the string. For clarity: the value returned is the number of 2855 ** bytes in the string, not the number of characters. 2856 ** 2857 ** Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 2858 ** even empty strings, are always zero terminated. The return 2859 ** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary 2860 ** pointer, possibly even a NULL pointer. 2861 ** 2862 ** The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes() 2863 ** but leaves the result in UTF-16 in native byte order instead of UTF-8. 2864 ** The zero terminator is not included in this count. 2865 ** 2866 ** The object returned by [sqlite3_column_value()] is an 2867 ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 2868 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 2869 ** If the [unprotected sqlite3_value] object returned by 2870 ** [sqlite3_column_value()] is used in any other way, including calls 2871 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 2872 ** or [sqlite3_value_bytes()], then the behavior is undefined. 2873 ** 2874 ** These routines attempt to convert the value where appropriate. For 2875 ** example, if the internal representation is FLOAT and a text result 2876 ** is requested, [sqlite3_snprintf()] is used internally to perform the 2877 ** conversion automatically. The following table details the conversions 2878 ** that are applied: 2879 ** 2880 ** <blockquote> 2881 ** <table border="1"> 2882 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 2883 ** 2884 ** <tr><td> NULL <td> INTEGER <td> Result is 0 2885 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0 2886 ** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 2887 ** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 2888 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 2889 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 2890 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 2891 ** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 2892 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 2893 ** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 2894 ** <tr><td> TEXT <td> INTEGER <td> Use atoi() 2895 ** <tr><td> TEXT <td> FLOAT <td> Use atof() 2896 ** <tr><td> TEXT <td> BLOB <td> No change 2897 ** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 2898 ** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 2899 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 2900 ** </table> 2901 ** </blockquote> 2902 ** 2903 ** The table above makes reference to standard C library functions atoi() 2904 ** and atof(). SQLite does not really use these functions. It has its 2905 ** own equivalent internal routines. The atoi() and atof() names are 2906 ** used in the table for brevity and because they are familiar to most 2907 ** C programmers. 2908 ** 2909 ** Note that when type conversions occur, pointers returned by prior 2910 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 2911 ** sqlite3_column_text16() may be invalidated. 2912 ** Type conversions and pointer invalidations might occur 2913 ** in the following cases: 2914 ** 2915 ** <ul> 2916 ** <li> The initial content is a BLOB and sqlite3_column_text() or 2917 ** sqlite3_column_text16() is called. A zero-terminator might 2918 ** need to be added to the string.</li> 2919 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 2920 ** sqlite3_column_text16() is called. The content must be converted 2921 ** to UTF-16.</li> 2922 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 2923 ** sqlite3_column_text() is called. The content must be converted 2924 ** to UTF-8.</li> 2925 ** </ul> 2926 ** 2927 ** Conversions between UTF-16be and UTF-16le are always done in place and do 2928 ** not invalidate a prior pointer, though of course the content of the buffer 2929 ** that the prior pointer points to will have been modified. Other kinds 2930 ** of conversion are done in place when it is possible, but sometimes they 2931 ** are not possible and in those cases prior pointers are invalidated. 2932 ** 2933 ** The safest and easiest to remember policy is to invoke these routines 2934 ** in one of the following ways: 2935 ** 2936 ** <ul> 2937 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 2938 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 2939 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 2940 ** </ul> 2941 ** 2942 ** In other words, you should call sqlite3_column_text(), 2943 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 2944 ** into the desired format, then invoke sqlite3_column_bytes() or 2945 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 2946 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to 2947 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 2948 ** with calls to sqlite3_column_bytes(). 2949 ** 2950 ** The pointers returned are valid until a type conversion occurs as 2951 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 2952 ** [sqlite3_finalize()] is called. The memory space used to hold strings 2953 ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 2954 ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 2955 ** [sqlite3_free()]. 2956 ** 2957 ** If a memory allocation error occurs during the evaluation of any 2958 ** of these routines, a default value is returned. The default value 2959 ** is either the integer 0, the floating point number 0.0, or a NULL 2960 ** pointer. Subsequent calls to [sqlite3_errcode()] will return 2961 ** [SQLITE_NOMEM]. 2962 ** 2963 ** Requirements: 2964 ** [H13803] [H13806] [H13809] [H13812] [H13815] [H13818] [H13821] [H13824] 2965 ** [H13827] [H13830] 2966 */ 2967 const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 2968 int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 2969 int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 2970 double sqlite3_column_double(sqlite3_stmt*, int iCol); 2971 int sqlite3_column_int(sqlite3_stmt*, int iCol); 2972 sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 2973 const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 2974 const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 2975 int sqlite3_column_type(sqlite3_stmt*, int iCol); 2976 sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 2977 2978 /* 2979 ** CAPI3REF: Destroy A Prepared Statement Object {H13300} <S70300><S30100> 2980 ** 2981 ** The sqlite3_finalize() function is called to delete a [prepared statement]. 2982 ** If the statement was executed successfully or not executed at all, then 2983 ** SQLITE_OK is returned. If execution of the statement failed then an 2984 ** [error code] or [extended error code] is returned. 2985 ** 2986 ** This routine can be called at any point during the execution of the 2987 ** [prepared statement]. If the virtual machine has not 2988 ** completed execution when this routine is called, that is like 2989 ** encountering an error or an [sqlite3_interrupt | interrupt]. 2990 ** Incomplete updates may be rolled back and transactions canceled, 2991 ** depending on the circumstances, and the 2992 ** [error code] returned will be [SQLITE_ABORT]. 2993 ** 2994 ** Requirements: 2995 ** [H11302] [H11304] 2996 */ 2997 int sqlite3_finalize(sqlite3_stmt *pStmt); 2998 2999 /* 3000 ** CAPI3REF: Reset A Prepared Statement Object {H13330} <S70300> 3001 ** 3002 ** The sqlite3_reset() function is called to reset a [prepared statement] 3003 ** object back to its initial state, ready to be re-executed. 3004 ** Any SQL statement variables that had values bound to them using 3005 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3006 ** Use [sqlite3_clear_bindings()] to reset the bindings. 3007 ** 3008 ** {H11332} The [sqlite3_reset(S)] interface resets the [prepared statement] S 3009 ** back to the beginning of its program. 3010 ** 3011 ** {H11334} If the most recent call to [sqlite3_step(S)] for the 3012 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3013 ** or if [sqlite3_step(S)] has never before been called on S, 3014 ** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3015 ** 3016 ** {H11336} If the most recent call to [sqlite3_step(S)] for the 3017 ** [prepared statement] S indicated an error, then 3018 ** [sqlite3_reset(S)] returns an appropriate [error code]. 3019 ** 3020 ** {H11338} The [sqlite3_reset(S)] interface does not change the values 3021 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3022 */ 3023 int sqlite3_reset(sqlite3_stmt *pStmt); 3024 3025 /* 3026 ** CAPI3REF: Create Or Redefine SQL Functions {H16100} <S20200> 3027 ** KEYWORDS: {function creation routines} 3028 ** KEYWORDS: {application-defined SQL function} 3029 ** KEYWORDS: {application-defined SQL functions} 3030 ** 3031 ** These two functions (collectively known as "function creation routines") 3032 ** are used to add SQL functions or aggregates or to redefine the behavior 3033 ** of existing SQL functions or aggregates. The only difference between the 3034 ** two is that the second parameter, the name of the (scalar) function or 3035 ** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16 3036 ** for sqlite3_create_function16(). 3037 ** 3038 ** The first parameter is the [database connection] to which the SQL 3039 ** function is to be added. If a single program uses more than one database 3040 ** connection internally, then SQL functions must be added individually to 3041 ** each database connection. 3042 ** 3043 ** The second parameter is the name of the SQL function to be created or 3044 ** redefined. The length of the name is limited to 255 bytes, exclusive of 3045 ** the zero-terminator. Note that the name length limit is in bytes, not 3046 ** characters. Any attempt to create a function with a longer name 3047 ** will result in [SQLITE_ERROR] being returned. 3048 ** 3049 ** The third parameter (nArg) 3050 ** is the number of arguments that the SQL function or 3051 ** aggregate takes. If this parameter is negative, then the SQL function or 3052 ** aggregate may take any number of arguments. 3053 ** 3054 ** The fourth parameter, eTextRep, specifies what 3055 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3056 ** its parameters. Any SQL function implementation should be able to work 3057 ** work with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3058 ** more efficient with one encoding than another. It is allowed to 3059 ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3060 ** times with the same function but with different values of eTextRep. 3061 ** When multiple implementations of the same function are available, SQLite 3062 ** will pick the one that involves the least amount of data conversion. 3063 ** If there is only a single implementation which does not care what text 3064 ** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3065 ** 3066 ** The fifth parameter is an arbitrary pointer. The implementation of the 3067 ** function can gain access to this pointer using [sqlite3_user_data()]. 3068 ** 3069 ** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are 3070 ** pointers to C-language functions that implement the SQL function or 3071 ** aggregate. A scalar SQL function requires an implementation of the xFunc 3072 ** callback only, NULL pointers should be passed as the xStep and xFinal 3073 ** parameters. An aggregate SQL function requires an implementation of xStep 3074 ** and xFinal and NULL should be passed for xFunc. To delete an existing 3075 ** SQL function or aggregate, pass NULL for all three function callbacks. 3076 ** 3077 ** It is permitted to register multiple implementations of the same 3078 ** functions with the same name but with either differing numbers of 3079 ** arguments or differing preferred text encodings. SQLite will use 3080 ** the implementation most closely matches the way in which the 3081 ** SQL function is used. A function implementation with a non-negative 3082 ** nArg parameter is a better match than a function implementation with 3083 ** a negative nArg. A function where the preferred text encoding 3084 ** matches the database encoding is a better 3085 ** match than a function where the encoding is different. 3086 ** A function where the encoding difference is between UTF16le and UTF16be 3087 ** is a closer match than a function where the encoding difference is 3088 ** between UTF8 and UTF16. 3089 ** 3090 ** Built-in functions may be overloaded by new application-defined functions. 3091 ** The first application-defined function with a given name overrides all 3092 ** built-in functions in the same [database connection] with the same name. 3093 ** Subsequent application-defined functions of the same name only override 3094 ** prior application-defined functions that are an exact match for the 3095 ** number of parameters and preferred encoding. 3096 ** 3097 ** An application-defined function is permitted to call other 3098 ** SQLite interfaces. However, such calls must not 3099 ** close the database connection nor finalize or reset the prepared 3100 ** statement in which the function is running. 3101 ** 3102 ** Requirements: 3103 ** [H16103] [H16106] [H16109] [H16112] [H16118] [H16121] [H16124] [H16127] 3104 ** [H16130] [H16133] [H16136] [H16139] [H16142] 3105 */ 3106 int sqlite3_create_function( 3107 sqlite3 *db, 3108 const char *zFunctionName, 3109 int nArg, 3110 int eTextRep, 3111 void *pApp, 3112 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3113 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3114 void (*xFinal)(sqlite3_context*) 3115 ); 3116 int sqlite3_create_function16( 3117 sqlite3 *db, 3118 const void *zFunctionName, 3119 int nArg, 3120 int eTextRep, 3121 void *pApp, 3122 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3123 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3124 void (*xFinal)(sqlite3_context*) 3125 ); 3126 3127 /* 3128 ** CAPI3REF: Text Encodings {H10267} <S50200> <H16100> 3129 ** 3130 ** These constant define integer codes that represent the various 3131 ** text encodings supported by SQLite. 3132 */ 3133 #define SQLITE_UTF8 1 3134 #define SQLITE_UTF16LE 2 3135 #define SQLITE_UTF16BE 3 3136 #define SQLITE_UTF16 4 /* Use native byte order */ 3137 #define SQLITE_ANY 5 /* sqlite3_create_function only */ 3138 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3139 3140 /* 3141 ** CAPI3REF: Deprecated Functions 3142 ** DEPRECATED 3143 ** 3144 ** These functions are [deprecated]. In order to maintain 3145 ** backwards compatibility with older code, these functions continue 3146 ** to be supported. However, new applications should avoid 3147 ** the use of these functions. To help encourage people to avoid 3148 ** using these functions, we are not going to tell you what they do. 3149 */ 3150 #ifndef SQLITE_OMIT_DEPRECATED 3151 SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3152 SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3153 SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3154 SQLITE_DEPRECATED int sqlite3_global_recover(void); 3155 SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3156 SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3157 #endif 3158 3159 /* 3160 ** CAPI3REF: Obtaining SQL Function Parameter Values {H15100} <S20200> 3161 ** 3162 ** The C-language implementation of SQL functions and aggregates uses 3163 ** this set of interface routines to access the parameter values on 3164 ** the function or aggregate. 3165 ** 3166 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3167 ** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3168 ** define callbacks that implement the SQL functions and aggregates. 3169 ** The 4th parameter to these callbacks is an array of pointers to 3170 ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3171 ** each parameter to the SQL function. These routines are used to 3172 ** extract values from the [sqlite3_value] objects. 3173 ** 3174 ** These routines work only with [protected sqlite3_value] objects. 3175 ** Any attempt to use these routines on an [unprotected sqlite3_value] 3176 ** object results in undefined behavior. 3177 ** 3178 ** These routines work just like the corresponding [column access functions] 3179 ** except that these routines take a single [protected sqlite3_value] object 3180 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3181 ** 3182 ** The sqlite3_value_text16() interface extracts a UTF-16 string 3183 ** in the native byte-order of the host machine. The 3184 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3185 ** extract UTF-16 strings as big-endian and little-endian respectively. 3186 ** 3187 ** The sqlite3_value_numeric_type() interface attempts to apply 3188 ** numeric affinity to the value. This means that an attempt is 3189 ** made to convert the value to an integer or floating point. If 3190 ** such a conversion is possible without loss of information (in other 3191 ** words, if the value is a string that looks like a number) 3192 ** then the conversion is performed. Otherwise no conversion occurs. 3193 ** The [SQLITE_INTEGER | datatype] after conversion is returned. 3194 ** 3195 ** Please pay particular attention to the fact that the pointer returned 3196 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3197 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3198 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3199 ** or [sqlite3_value_text16()]. 3200 ** 3201 ** These routines must be called from the same thread as 3202 ** the SQL function that supplied the [sqlite3_value*] parameters. 3203 ** 3204 ** Requirements: 3205 ** [H15103] [H15106] [H15109] [H15112] [H15115] [H15118] [H15121] [H15124] 3206 ** [H15127] [H15130] [H15133] [H15136] 3207 */ 3208 const void *sqlite3_value_blob(sqlite3_value*); 3209 int sqlite3_value_bytes(sqlite3_value*); 3210 int sqlite3_value_bytes16(sqlite3_value*); 3211 double sqlite3_value_double(sqlite3_value*); 3212 int sqlite3_value_int(sqlite3_value*); 3213 sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3214 const unsigned char *sqlite3_value_text(sqlite3_value*); 3215 const void *sqlite3_value_text16(sqlite3_value*); 3216 const void *sqlite3_value_text16le(sqlite3_value*); 3217 const void *sqlite3_value_text16be(sqlite3_value*); 3218 int sqlite3_value_type(sqlite3_value*); 3219 int sqlite3_value_numeric_type(sqlite3_value*); 3220 3221 /* 3222 ** CAPI3REF: Obtain Aggregate Function Context {H16210} <S20200> 3223 ** 3224 ** The implementation of aggregate SQL functions use this routine to allocate 3225 ** a structure for storing their state. 3226 ** 3227 ** The first time the sqlite3_aggregate_context() routine is called for a 3228 ** particular aggregate, SQLite allocates nBytes of memory, zeroes out that 3229 ** memory, and returns a pointer to it. On second and subsequent calls to 3230 ** sqlite3_aggregate_context() for the same aggregate function index, 3231 ** the same buffer is returned. The implementation of the aggregate can use 3232 ** the returned buffer to accumulate data. 3233 ** 3234 ** SQLite automatically frees the allocated buffer when the aggregate 3235 ** query concludes. 3236 ** 3237 ** The first parameter should be a copy of the 3238 ** [sqlite3_context | SQL function context] that is the first parameter 3239 ** to the callback routine that implements the aggregate function. 3240 ** 3241 ** This routine must be called from the same thread in which 3242 ** the aggregate SQL function is running. 3243 ** 3244 ** Requirements: 3245 ** [H16211] [H16213] [H16215] [H16217] 3246 */ 3247 void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 3248 3249 /* 3250 ** CAPI3REF: User Data For Functions {H16240} <S20200> 3251 ** 3252 ** The sqlite3_user_data() interface returns a copy of 3253 ** the pointer that was the pUserData parameter (the 5th parameter) 3254 ** of the [sqlite3_create_function()] 3255 ** and [sqlite3_create_function16()] routines that originally 3256 ** registered the application defined function. {END} 3257 ** 3258 ** This routine must be called from the same thread in which 3259 ** the application-defined function is running. 3260 ** 3261 ** Requirements: 3262 ** [H16243] 3263 */ 3264 void *sqlite3_user_data(sqlite3_context*); 3265 3266 /* 3267 ** CAPI3REF: Database Connection For Functions {H16250} <S60600><S20200> 3268 ** 3269 ** The sqlite3_context_db_handle() interface returns a copy of 3270 ** the pointer to the [database connection] (the 1st parameter) 3271 ** of the [sqlite3_create_function()] 3272 ** and [sqlite3_create_function16()] routines that originally 3273 ** registered the application defined function. 3274 ** 3275 ** Requirements: 3276 ** [H16253] 3277 */ 3278 sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 3279 3280 /* 3281 ** CAPI3REF: Function Auxiliary Data {H16270} <S20200> 3282 ** 3283 ** The following two functions may be used by scalar SQL functions to 3284 ** associate metadata with argument values. If the same value is passed to 3285 ** multiple invocations of the same SQL function during query execution, under 3286 ** some circumstances the associated metadata may be preserved. This may 3287 ** be used, for example, to add a regular-expression matching scalar 3288 ** function. The compiled version of the regular expression is stored as 3289 ** metadata associated with the SQL value passed as the regular expression 3290 ** pattern. The compiled regular expression can be reused on multiple 3291 ** invocations of the same function so that the original pattern string 3292 ** does not need to be recompiled on each invocation. 3293 ** 3294 ** The sqlite3_get_auxdata() interface returns a pointer to the metadata 3295 ** associated by the sqlite3_set_auxdata() function with the Nth argument 3296 ** value to the application-defined function. If no metadata has been ever 3297 ** been set for the Nth argument of the function, or if the corresponding 3298 ** function parameter has changed since the meta-data was set, 3299 ** then sqlite3_get_auxdata() returns a NULL pointer. 3300 ** 3301 ** The sqlite3_set_auxdata() interface saves the metadata 3302 ** pointed to by its 3rd parameter as the metadata for the N-th 3303 ** argument of the application-defined function. Subsequent 3304 ** calls to sqlite3_get_auxdata() might return this data, if it has 3305 ** not been destroyed. 3306 ** If it is not NULL, SQLite will invoke the destructor 3307 ** function given by the 4th parameter to sqlite3_set_auxdata() on 3308 ** the metadata when the corresponding function parameter changes 3309 ** or when the SQL statement completes, whichever comes first. 3310 ** 3311 ** SQLite is free to call the destructor and drop metadata on any 3312 ** parameter of any function at any time. The only guarantee is that 3313 ** the destructor will be called before the metadata is dropped. 3314 ** 3315 ** In practice, metadata is preserved between function calls for 3316 ** expressions that are constant at compile time. This includes literal 3317 ** values and SQL variables. 3318 ** 3319 ** These routines must be called from the same thread in which 3320 ** the SQL function is running. 3321 ** 3322 ** Requirements: 3323 ** [H16272] [H16274] [H16276] [H16277] [H16278] [H16279] 3324 */ 3325 void *sqlite3_get_auxdata(sqlite3_context*, int N); 3326 void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 3327 3328 3329 /* 3330 ** CAPI3REF: Constants Defining Special Destructor Behavior {H10280} <S30100> 3331 ** 3332 ** These are special values for the destructor that is passed in as the 3333 ** final argument to routines like [sqlite3_result_blob()]. If the destructor 3334 ** argument is SQLITE_STATIC, it means that the content pointer is constant 3335 ** and will never change. It does not need to be destroyed. The 3336 ** SQLITE_TRANSIENT value means that the content will likely change in 3337 ** the near future and that SQLite should make its own private copy of 3338 ** the content before returning. 3339 ** 3340 ** The typedef is necessary to work around problems in certain 3341 ** C++ compilers. See ticket #2191. 3342 */ 3343 typedef void (*sqlite3_destructor_type)(void*); 3344 #define SQLITE_STATIC ((sqlite3_destructor_type)0) 3345 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 3346 3347 /* 3348 ** CAPI3REF: Setting The Result Of An SQL Function {H16400} <S20200> 3349 ** 3350 ** These routines are used by the xFunc or xFinal callbacks that 3351 ** implement SQL functions and aggregates. See 3352 ** [sqlite3_create_function()] and [sqlite3_create_function16()] 3353 ** for additional information. 3354 ** 3355 ** These functions work very much like the [parameter binding] family of 3356 ** functions used to bind values to host parameters in prepared statements. 3357 ** Refer to the [SQL parameter] documentation for additional information. 3358 ** 3359 ** The sqlite3_result_blob() interface sets the result from 3360 ** an application-defined function to be the BLOB whose content is pointed 3361 ** to by the second parameter and which is N bytes long where N is the 3362 ** third parameter. 3363 ** 3364 ** The sqlite3_result_zeroblob() interfaces set the result of 3365 ** the application-defined function to be a BLOB containing all zero 3366 ** bytes and N bytes in size, where N is the value of the 2nd parameter. 3367 ** 3368 ** The sqlite3_result_double() interface sets the result from 3369 ** an application-defined function to be a floating point value specified 3370 ** by its 2nd argument. 3371 ** 3372 ** The sqlite3_result_error() and sqlite3_result_error16() functions 3373 ** cause the implemented SQL function to throw an exception. 3374 ** SQLite uses the string pointed to by the 3375 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 3376 ** as the text of an error message. SQLite interprets the error 3377 ** message string from sqlite3_result_error() as UTF-8. SQLite 3378 ** interprets the string from sqlite3_result_error16() as UTF-16 in native 3379 ** byte order. If the third parameter to sqlite3_result_error() 3380 ** or sqlite3_result_error16() is negative then SQLite takes as the error 3381 ** message all text up through the first zero character. 3382 ** If the third parameter to sqlite3_result_error() or 3383 ** sqlite3_result_error16() is non-negative then SQLite takes that many 3384 ** bytes (not characters) from the 2nd parameter as the error message. 3385 ** The sqlite3_result_error() and sqlite3_result_error16() 3386 ** routines make a private copy of the error message text before 3387 ** they return. Hence, the calling function can deallocate or 3388 ** modify the text after they return without harm. 3389 ** The sqlite3_result_error_code() function changes the error code 3390 ** returned by SQLite as a result of an error in a function. By default, 3391 ** the error code is SQLITE_ERROR. A subsequent call to sqlite3_result_error() 3392 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 3393 ** 3394 ** The sqlite3_result_toobig() interface causes SQLite to throw an error 3395 ** indicating that a string or BLOB is to long to represent. 3396 ** 3397 ** The sqlite3_result_nomem() interface causes SQLite to throw an error 3398 ** indicating that a memory allocation failed. 3399 ** 3400 ** The sqlite3_result_int() interface sets the return value 3401 ** of the application-defined function to be the 32-bit signed integer 3402 ** value given in the 2nd argument. 3403 ** The sqlite3_result_int64() interface sets the return value 3404 ** of the application-defined function to be the 64-bit signed integer 3405 ** value given in the 2nd argument. 3406 ** 3407 ** The sqlite3_result_null() interface sets the return value 3408 ** of the application-defined function to be NULL. 3409 ** 3410 ** The sqlite3_result_text(), sqlite3_result_text16(), 3411 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 3412 ** set the return value of the application-defined function to be 3413 ** a text string which is represented as UTF-8, UTF-16 native byte order, 3414 ** UTF-16 little endian, or UTF-16 big endian, respectively. 3415 ** SQLite takes the text result from the application from 3416 ** the 2nd parameter of the sqlite3_result_text* interfaces. 3417 ** If the 3rd parameter to the sqlite3_result_text* interfaces 3418 ** is negative, then SQLite takes result text from the 2nd parameter 3419 ** through the first zero character. 3420 ** If the 3rd parameter to the sqlite3_result_text* interfaces 3421 ** is non-negative, then as many bytes (not characters) of the text 3422 ** pointed to by the 2nd parameter are taken as the application-defined 3423 ** function result. 3424 ** If the 4th parameter to the sqlite3_result_text* interfaces 3425 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 3426 ** function as the destructor on the text or BLOB result when it has 3427 ** finished using that result. 3428 ** If the 4th parameter to the sqlite3_result_text* interfaces or 3429 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 3430 ** assumes that the text or BLOB result is in constant space and does not 3431 ** copy the it or call a destructor when it has finished using that result. 3432 ** If the 4th parameter to the sqlite3_result_text* interfaces 3433 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 3434 ** then SQLite makes a copy of the result into space obtained from 3435 ** from [sqlite3_malloc()] before it returns. 3436 ** 3437 ** The sqlite3_result_value() interface sets the result of 3438 ** the application-defined function to be a copy the 3439 ** [unprotected sqlite3_value] object specified by the 2nd parameter. The 3440 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 3441 ** so that the [sqlite3_value] specified in the parameter may change or 3442 ** be deallocated after sqlite3_result_value() returns without harm. 3443 ** A [protected sqlite3_value] object may always be used where an 3444 ** [unprotected sqlite3_value] object is required, so either 3445 ** kind of [sqlite3_value] object can be used with this interface. 3446 ** 3447 ** If these routines are called from within the different thread 3448 ** than the one containing the application-defined function that received 3449 ** the [sqlite3_context] pointer, the results are undefined. 3450 ** 3451 ** Requirements: 3452 ** [H16403] [H16406] [H16409] [H16412] [H16415] [H16418] [H16421] [H16424] 3453 ** [H16427] [H16430] [H16433] [H16436] [H16439] [H16442] [H16445] [H16448] 3454 ** [H16451] [H16454] [H16457] [H16460] [H16463] 3455 */ 3456 void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 3457 void sqlite3_result_double(sqlite3_context*, double); 3458 void sqlite3_result_error(sqlite3_context*, const char*, int); 3459 void sqlite3_result_error16(sqlite3_context*, const void*, int); 3460 void sqlite3_result_error_toobig(sqlite3_context*); 3461 void sqlite3_result_error_nomem(sqlite3_context*); 3462 void sqlite3_result_error_code(sqlite3_context*, int); 3463 void sqlite3_result_int(sqlite3_context*, int); 3464 void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 3465 void sqlite3_result_null(sqlite3_context*); 3466 void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 3467 void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 3468 void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 3469 void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 3470 void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 3471 void sqlite3_result_zeroblob(sqlite3_context*, int n); 3472 3473 /* 3474 ** CAPI3REF: Define New Collating Sequences {H16600} <S20300> 3475 ** 3476 ** These functions are used to add new collation sequences to the 3477 ** [database connection] specified as the first argument. 3478 ** 3479 ** The name of the new collation sequence is specified as a UTF-8 string 3480 ** for sqlite3_create_collation() and sqlite3_create_collation_v2() 3481 ** and a UTF-16 string for sqlite3_create_collation16(). In all cases 3482 ** the name is passed as the second function argument. 3483 ** 3484 ** The third argument may be one of the constants [SQLITE_UTF8], 3485 ** [SQLITE_UTF16LE] or [SQLITE_UTF16BE], indicating that the user-supplied 3486 ** routine expects to be passed pointers to strings encoded using UTF-8, 3487 ** UTF-16 little-endian, or UTF-16 big-endian, respectively. The 3488 ** third argument might also be [SQLITE_UTF16_ALIGNED] to indicate that 3489 ** the routine expects pointers to 16-bit word aligned strings 3490 ** of UTF-16 in the native byte order of the host computer. 3491 ** 3492 ** A pointer to the user supplied routine must be passed as the fifth 3493 ** argument. If it is NULL, this is the same as deleting the collation 3494 ** sequence (so that SQLite cannot call it anymore). 3495 ** Each time the application supplied function is invoked, it is passed 3496 ** as its first parameter a copy of the void* passed as the fourth argument 3497 ** to sqlite3_create_collation() or sqlite3_create_collation16(). 3498 ** 3499 ** The remaining arguments to the application-supplied routine are two strings, 3500 ** each represented by a (length, data) pair and encoded in the encoding 3501 ** that was passed as the third argument when the collation sequence was 3502 ** registered. {END} The application defined collation routine should 3503 ** return negative, zero or positive if the first string is less than, 3504 ** equal to, or greater than the second string. i.e. (STRING1 - STRING2). 3505 ** 3506 ** The sqlite3_create_collation_v2() works like sqlite3_create_collation() 3507 ** except that it takes an extra argument which is a destructor for 3508 ** the collation. The destructor is called when the collation is 3509 ** destroyed and is passed a copy of the fourth parameter void* pointer 3510 ** of the sqlite3_create_collation_v2(). 3511 ** Collations are destroyed when they are overridden by later calls to the 3512 ** collation creation functions or when the [database connection] is closed 3513 ** using [sqlite3_close()]. 3514 ** 3515 ** Requirements: 3516 ** [H16603] [H16604] [H16606] [H16609] [H16612] [H16615] [H16618] [H16621] 3517 ** [H16624] [H16627] [H16630] 3518 */ 3519 int sqlite3_create_collation( 3520 sqlite3*, 3521 const char *zName, 3522 int eTextRep, 3523 void*, 3524 int(*xCompare)(void*,int,const void*,int,const void*) 3525 ); 3526 int sqlite3_create_collation_v2( 3527 sqlite3*, 3528 const char *zName, 3529 int eTextRep, 3530 void*, 3531 int(*xCompare)(void*,int,const void*,int,const void*), 3532 void(*xDestroy)(void*) 3533 ); 3534 int sqlite3_create_collation16( 3535 sqlite3*, 3536 const void *zName, 3537 int eTextRep, 3538 void*, 3539 int(*xCompare)(void*,int,const void*,int,const void*) 3540 ); 3541 3542 /* 3543 ** CAPI3REF: Collation Needed Callbacks {H16700} <S20300> 3544 ** 3545 ** To avoid having to register all collation sequences before a database 3546 ** can be used, a single callback function may be registered with the 3547 ** [database connection] to be called whenever an undefined collation 3548 ** sequence is required. 3549 ** 3550 ** If the function is registered using the sqlite3_collation_needed() API, 3551 ** then it is passed the names of undefined collation sequences as strings 3552 ** encoded in UTF-8. {H16703} If sqlite3_collation_needed16() is used, 3553 ** the names are passed as UTF-16 in machine native byte order. 3554 ** A call to either function replaces any existing callback. 3555 ** 3556 ** When the callback is invoked, the first argument passed is a copy 3557 ** of the second argument to sqlite3_collation_needed() or 3558 ** sqlite3_collation_needed16(). The second argument is the database 3559 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 3560 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 3561 ** sequence function required. The fourth parameter is the name of the 3562 ** required collation sequence. 3563 ** 3564 ** The callback function should register the desired collation using 3565 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 3566 ** [sqlite3_create_collation_v2()]. 3567 ** 3568 ** Requirements: 3569 ** [H16702] [H16704] [H16706] 3570 */ 3571 int sqlite3_collation_needed( 3572 sqlite3*, 3573 void*, 3574 void(*)(void*,sqlite3*,int eTextRep,const char*) 3575 ); 3576 int sqlite3_collation_needed16( 3577 sqlite3*, 3578 void*, 3579 void(*)(void*,sqlite3*,int eTextRep,const void*) 3580 ); 3581 3582 /* 3583 ** Specify the key for an encrypted database. This routine should be 3584 ** called right after sqlite3_open(). 3585 ** 3586 ** The code to implement this API is not available in the public release 3587 ** of SQLite. 3588 */ 3589 int sqlite3_key( 3590 sqlite3 *db, /* Database to be rekeyed */ 3591 const void *pKey, int nKey /* The key */ 3592 ); 3593 3594 /* 3595 ** Change the key on an open database. If the current database is not 3596 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 3597 ** database is decrypted. 3598 ** 3599 ** The code to implement this API is not available in the public release 3600 ** of SQLite. 3601 */ 3602 int sqlite3_rekey( 3603 sqlite3 *db, /* Database to be rekeyed */ 3604 const void *pKey, int nKey /* The new key */ 3605 ); 3606 3607 /* 3608 ** CAPI3REF: Suspend Execution For A Short Time {H10530} <S40410> 3609 ** 3610 ** The sqlite3_sleep() function causes the current thread to suspend execution 3611 ** for at least a number of milliseconds specified in its parameter. 3612 ** 3613 ** If the operating system does not support sleep requests with 3614 ** millisecond time resolution, then the time will be rounded up to 3615 ** the nearest second. The number of milliseconds of sleep actually 3616 ** requested from the operating system is returned. 3617 ** 3618 ** SQLite implements this interface by calling the xSleep() 3619 ** method of the default [sqlite3_vfs] object. 3620 ** 3621 ** Requirements: [H10533] [H10536] 3622 */ 3623 int sqlite3_sleep(int); 3624 3625 /* 3626 ** CAPI3REF: Name Of The Folder Holding Temporary Files {H10310} <S20000> 3627 ** 3628 ** If this global variable is made to point to a string which is 3629 ** the name of a folder (a.k.a. directory), then all temporary files 3630 ** created by SQLite will be placed in that directory. If this variable 3631 ** is a NULL pointer, then SQLite performs a search for an appropriate 3632 ** temporary file directory. 3633 ** 3634 ** It is not safe to modify this variable once a [database connection] 3635 ** has been opened. It is intended that this variable be set once 3636 ** as part of process initialization and before any SQLite interface 3637 ** routines have been call and remain unchanged thereafter. 3638 */ 3639 SQLITE_EXTERN char *sqlite3_temp_directory; 3640 3641 /* 3642 ** CAPI3REF: Test For Auto-Commit Mode {H12930} <S60200> 3643 ** KEYWORDS: {autocommit mode} 3644 ** 3645 ** The sqlite3_get_autocommit() interface returns non-zero or 3646 ** zero if the given database connection is or is not in autocommit mode, 3647 ** respectively. Autocommit mode is on by default. 3648 ** Autocommit mode is disabled by a [BEGIN] statement. 3649 ** Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 3650 ** 3651 ** If certain kinds of errors occur on a statement within a multi-statement 3652 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 3653 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 3654 ** transaction might be rolled back automatically. The only way to 3655 ** find out whether SQLite automatically rolled back the transaction after 3656 ** an error is to use this function. 3657 ** 3658 ** If another thread changes the autocommit status of the database 3659 ** connection while this routine is running, then the return value 3660 ** is undefined. 3661 ** 3662 ** Requirements: [H12931] [H12932] [H12933] [H12934] 3663 */ 3664 int sqlite3_get_autocommit(sqlite3*); 3665 3666 /* 3667 ** CAPI3REF: Find The Database Handle Of A Prepared Statement {H13120} <S60600> 3668 ** 3669 ** The sqlite3_db_handle interface returns the [database connection] handle 3670 ** to which a [prepared statement] belongs. The [database connection] 3671 ** returned by sqlite3_db_handle is the same [database connection] that was the first argument 3672 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 3673 ** create the statement in the first place. 3674 ** 3675 ** Requirements: [H13123] 3676 */ 3677 sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 3678 3679 /* 3680 ** CAPI3REF: Find the next prepared statement {H13140} <S60600> 3681 ** 3682 ** This interface returns a pointer to the next [prepared statement] after 3683 ** pStmt associated with the [database connection] pDb. If pStmt is NULL 3684 ** then this interface returns a pointer to the first prepared statement 3685 ** associated with the database connection pDb. If no prepared statement 3686 ** satisfies the conditions of this routine, it returns NULL. 3687 ** 3688 ** The [database connection] pointer D in a call to 3689 ** [sqlite3_next_stmt(D,S)] must refer to an open database 3690 ** connection and in particular must not be a NULL pointer. 3691 ** 3692 ** Requirements: [H13143] [H13146] [H13149] [H13152] 3693 */ 3694 sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 3695 3696 /* 3697 ** CAPI3REF: Commit And Rollback Notification Callbacks {H12950} <S60400> 3698 ** 3699 ** The sqlite3_commit_hook() interface registers a callback 3700 ** function to be invoked whenever a transaction is committed. 3701 ** Any callback set by a previous call to sqlite3_commit_hook() 3702 ** for the same database connection is overridden. 3703 ** The sqlite3_rollback_hook() interface registers a callback 3704 ** function to be invoked whenever a transaction is committed. 3705 ** Any callback set by a previous call to sqlite3_commit_hook() 3706 ** for the same database connection is overridden. 3707 ** The pArg argument is passed through to the callback. 3708 ** If the callback on a commit hook function returns non-zero, 3709 ** then the commit is converted into a rollback. 3710 ** 3711 ** If another function was previously registered, its 3712 ** pArg value is returned. Otherwise NULL is returned. 3713 ** 3714 ** The callback implementation must not do anything that will modify 3715 ** the database connection that invoked the callback. Any actions 3716 ** to modify the database connection must be deferred until after the 3717 ** completion of the [sqlite3_step()] call that triggered the commit 3718 ** or rollback hook in the first place. 3719 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3720 ** database connections for the meaning of "modify" in this paragraph. 3721 ** 3722 ** Registering a NULL function disables the callback. 3723 ** 3724 ** For the purposes of this API, a transaction is said to have been 3725 ** rolled back if an explicit "ROLLBACK" statement is executed, or 3726 ** an error or constraint causes an implicit rollback to occur. 3727 ** The rollback callback is not invoked if a transaction is 3728 ** automatically rolled back because the database connection is closed. 3729 ** The rollback callback is not invoked if a transaction is 3730 ** rolled back because a commit callback returned non-zero. 3731 ** <todo> Check on this </todo> 3732 ** 3733 ** Requirements: 3734 ** [H12951] [H12952] [H12953] [H12954] [H12955] 3735 ** [H12961] [H12962] [H12963] [H12964] 3736 */ 3737 void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 3738 void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 3739 3740 /* 3741 ** CAPI3REF: Data Change Notification Callbacks {H12970} <S60400> 3742 ** 3743 ** The sqlite3_update_hook() interface registers a callback function 3744 ** with the [database connection] identified by the first argument 3745 ** to be invoked whenever a row is updated, inserted or deleted. 3746 ** Any callback set by a previous call to this function 3747 ** for the same database connection is overridden. 3748 ** 3749 ** The second argument is a pointer to the function to invoke when a 3750 ** row is updated, inserted or deleted. 3751 ** The first argument to the callback is a copy of the third argument 3752 ** to sqlite3_update_hook(). 3753 ** The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 3754 ** or [SQLITE_UPDATE], depending on the operation that caused the callback 3755 ** to be invoked. 3756 ** The third and fourth arguments to the callback contain pointers to the 3757 ** database and table name containing the affected row. 3758 ** The final callback parameter is the [rowid] of the row. 3759 ** In the case of an update, this is the [rowid] after the update takes place. 3760 ** 3761 ** The update hook is not invoked when internal system tables are 3762 ** modified (i.e. sqlite_master and sqlite_sequence). 3763 ** 3764 ** The update hook implementation must not do anything that will modify 3765 ** the database connection that invoked the update hook. Any actions 3766 ** to modify the database connection must be deferred until after the 3767 ** completion of the [sqlite3_step()] call that triggered the update hook. 3768 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3769 ** database connections for the meaning of "modify" in this paragraph. 3770 ** 3771 ** If another function was previously registered, its pArg value 3772 ** is returned. Otherwise NULL is returned. 3773 ** 3774 ** Requirements: 3775 ** [H12971] [H12973] [H12975] [H12977] [H12979] [H12981] [H12983] [H12986] 3776 */ 3777 void *sqlite3_update_hook( 3778 sqlite3*, 3779 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 3780 void* 3781 ); 3782 3783 /* 3784 ** CAPI3REF: Enable Or Disable Shared Pager Cache {H10330} <S30900> 3785 ** KEYWORDS: {shared cache} {shared cache mode} 3786 ** 3787 ** This routine enables or disables the sharing of the database cache 3788 ** and schema data structures between [database connection | connections] 3789 ** to the same database. Sharing is enabled if the argument is true 3790 ** and disabled if the argument is false. 3791 ** 3792 ** Cache sharing is enabled and disabled for an entire process. 3793 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 3794 ** sharing was enabled or disabled for each thread separately. 3795 ** 3796 ** The cache sharing mode set by this interface effects all subsequent 3797 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 3798 ** Existing database connections continue use the sharing mode 3799 ** that was in effect at the time they were opened. 3800 ** 3801 ** Virtual tables cannot be used with a shared cache. When shared 3802 ** cache is enabled, the [sqlite3_create_module()] API used to register 3803 ** virtual tables will always return an error. 3804 ** 3805 ** This routine returns [SQLITE_OK] if shared cache was enabled or disabled 3806 ** successfully. An [error code] is returned otherwise. 3807 ** 3808 ** Shared cache is disabled by default. But this might change in 3809 ** future releases of SQLite. Applications that care about shared 3810 ** cache setting should set it explicitly. 3811 ** 3812 ** See Also: [SQLite Shared-Cache Mode] 3813 ** 3814 ** Requirements: [H10331] [H10336] [H10337] [H10339] 3815 */ 3816 int sqlite3_enable_shared_cache(int); 3817 3818 /* 3819 ** CAPI3REF: Attempt To Free Heap Memory {H17340} <S30220> 3820 ** 3821 ** The sqlite3_release_memory() interface attempts to free N bytes 3822 ** of heap memory by deallocating non-essential memory allocations 3823 ** held by the database library. {END} Memory used to cache database 3824 ** pages to improve performance is an example of non-essential memory. 3825 ** sqlite3_release_memory() returns the number of bytes actually freed, 3826 ** which might be more or less than the amount requested. 3827 ** 3828 ** Requirements: [H17341] [H17342] 3829 */ 3830 int sqlite3_release_memory(int); 3831 3832 /* 3833 ** CAPI3REF: Impose A Limit On Heap Size {H17350} <S30220> 3834 ** 3835 ** The sqlite3_soft_heap_limit() interface places a "soft" limit 3836 ** on the amount of heap memory that may be allocated by SQLite. 3837 ** If an internal allocation is requested that would exceed the 3838 ** soft heap limit, [sqlite3_release_memory()] is invoked one or 3839 ** more times to free up some space before the allocation is performed. 3840 ** 3841 ** The limit is called "soft", because if [sqlite3_release_memory()] 3842 ** cannot free sufficient memory to prevent the limit from being exceeded, 3843 ** the memory is allocated anyway and the current operation proceeds. 3844 ** 3845 ** A negative or zero value for N means that there is no soft heap limit and 3846 ** [sqlite3_release_memory()] will only be called when memory is exhausted. 3847 ** The default value for the soft heap limit is zero. 3848 ** 3849 ** SQLite makes a best effort to honor the soft heap limit. 3850 ** But if the soft heap limit cannot be honored, execution will 3851 ** continue without error or notification. This is why the limit is 3852 ** called a "soft" limit. It is advisory only. 3853 ** 3854 ** Prior to SQLite version 3.5.0, this routine only constrained the memory 3855 ** allocated by a single thread - the same thread in which this routine 3856 ** runs. Beginning with SQLite version 3.5.0, the soft heap limit is 3857 ** applied to all threads. The value specified for the soft heap limit 3858 ** is an upper bound on the total memory allocation for all threads. In 3859 ** version 3.5.0 there is no mechanism for limiting the heap usage for 3860 ** individual threads. 3861 ** 3862 ** Requirements: 3863 ** [H16351] [H16352] [H16353] [H16354] [H16355] [H16358] 3864 */ 3865 void sqlite3_soft_heap_limit(int); 3866 3867 /* 3868 ** CAPI3REF: Extract Metadata About A Column Of A Table {H12850} <S60300> 3869 ** 3870 ** This routine returns metadata about a specific column of a specific 3871 ** database table accessible using the [database connection] handle 3872 ** passed as the first function argument. 3873 ** 3874 ** The column is identified by the second, third and fourth parameters to 3875 ** this function. The second parameter is either the name of the database 3876 ** (i.e. "main", "temp" or an attached database) containing the specified 3877 ** table or NULL. If it is NULL, then all attached databases are searched 3878 ** for the table using the same algorithm used by the database engine to 3879 ** resolve unqualified table references. 3880 ** 3881 ** The third and fourth parameters to this function are the table and column 3882 ** name of the desired column, respectively. Neither of these parameters 3883 ** may be NULL. 3884 ** 3885 ** Metadata is returned by writing to the memory locations passed as the 5th 3886 ** and subsequent parameters to this function. Any of these arguments may be 3887 ** NULL, in which case the corresponding element of metadata is omitted. 3888 ** 3889 ** <blockquote> 3890 ** <table border="1"> 3891 ** <tr><th> Parameter <th> Output<br>Type <th> Description 3892 ** 3893 ** <tr><td> 5th <td> const char* <td> Data type 3894 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence 3895 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 3896 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 3897 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 3898 ** </table> 3899 ** </blockquote> 3900 ** 3901 ** The memory pointed to by the character pointers returned for the 3902 ** declaration type and collation sequence is valid only until the next 3903 ** call to any SQLite API function. 3904 ** 3905 ** If the specified table is actually a view, an [error code] is returned. 3906 ** 3907 ** If the specified column is "rowid", "oid" or "_rowid_" and an 3908 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 3909 ** parameters are set for the explicitly declared column. If there is no 3910 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output 3911 ** parameters are set as follows: 3912 ** 3913 ** <pre> 3914 ** data type: "INTEGER" 3915 ** collation sequence: "BINARY" 3916 ** not null: 0 3917 ** primary key: 1 3918 ** auto increment: 0 3919 ** </pre> 3920 ** 3921 ** This function may load one or more schemas from database files. If an 3922 ** error occurs during this process, or if the requested table or column 3923 ** cannot be found, an [error code] is returned and an error message left 3924 ** in the [database connection] (to be retrieved using sqlite3_errmsg()). 3925 ** 3926 ** This API is only available if the library was compiled with the 3927 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 3928 */ 3929 int sqlite3_table_column_metadata( 3930 sqlite3 *db, /* Connection handle */ 3931 const char *zDbName, /* Database name or NULL */ 3932 const char *zTableName, /* Table name */ 3933 const char *zColumnName, /* Column name */ 3934 char const **pzDataType, /* OUTPUT: Declared data type */ 3935 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 3936 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 3937 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 3938 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 3939 ); 3940 3941 /* 3942 ** CAPI3REF: Load An Extension {H12600} <S20500> 3943 ** 3944 ** This interface loads an SQLite extension library from the named file. 3945 ** 3946 ** {H12601} The sqlite3_load_extension() interface attempts to load an 3947 ** SQLite extension library contained in the file zFile. 3948 ** 3949 ** {H12602} The entry point is zProc. 3950 ** 3951 ** {H12603} zProc may be 0, in which case the name of the entry point 3952 ** defaults to "sqlite3_extension_init". 3953 ** 3954 ** {H12604} The sqlite3_load_extension() interface shall return 3955 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 3956 ** 3957 ** {H12605} If an error occurs and pzErrMsg is not 0, then the 3958 ** [sqlite3_load_extension()] interface shall attempt to 3959 ** fill *pzErrMsg with error message text stored in memory 3960 ** obtained from [sqlite3_malloc()]. {END} The calling function 3961 ** should free this memory by calling [sqlite3_free()]. 3962 ** 3963 ** {H12606} Extension loading must be enabled using 3964 ** [sqlite3_enable_load_extension()] prior to calling this API, 3965 ** otherwise an error will be returned. 3966 */ 3967 int sqlite3_load_extension( 3968 sqlite3 *db, /* Load the extension into this database connection */ 3969 const char *zFile, /* Name of the shared library containing extension */ 3970 const char *zProc, /* Entry point. Derived from zFile if 0 */ 3971 char **pzErrMsg /* Put error message here if not 0 */ 3972 ); 3973 3974 /* 3975 ** CAPI3REF: Enable Or Disable Extension Loading {H12620} <S20500> 3976 ** 3977 ** So as not to open security holes in older applications that are 3978 ** unprepared to deal with extension loading, and as a means of disabling 3979 ** extension loading while evaluating user-entered SQL, the following API 3980 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 3981 ** 3982 ** Extension loading is off by default. See ticket #1863. 3983 ** 3984 ** {H12621} Call the sqlite3_enable_load_extension() routine with onoff==1 3985 ** to turn extension loading on and call it with onoff==0 to turn 3986 ** it back off again. 3987 ** 3988 ** {H12622} Extension loading is off by default. 3989 */ 3990 int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 3991 3992 /* 3993 ** CAPI3REF: Automatically Load An Extensions {H12640} <S20500> 3994 ** 3995 ** This API can be invoked at program startup in order to register 3996 ** one or more statically linked extensions that will be available 3997 ** to all new [database connections]. {END} 3998 ** 3999 ** This routine stores a pointer to the extension in an array that is 4000 ** obtained from [sqlite3_malloc()]. If you run a memory leak checker 4001 ** on your program and it reports a leak because of this array, invoke 4002 ** [sqlite3_reset_auto_extension()] prior to shutdown to free the memory. 4003 ** 4004 ** {H12641} This function registers an extension entry point that is 4005 ** automatically invoked whenever a new [database connection] 4006 ** is opened using [sqlite3_open()], [sqlite3_open16()], 4007 ** or [sqlite3_open_v2()]. 4008 ** 4009 ** {H12642} Duplicate extensions are detected so calling this routine 4010 ** multiple times with the same extension is harmless. 4011 ** 4012 ** {H12643} This routine stores a pointer to the extension in an array 4013 ** that is obtained from [sqlite3_malloc()]. 4014 ** 4015 ** {H12644} Automatic extensions apply across all threads. 4016 */ 4017 int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4018 4019 /* 4020 ** CAPI3REF: Reset Automatic Extension Loading {H12660} <S20500> 4021 ** 4022 ** This function disables all previously registered automatic 4023 ** extensions. {END} It undoes the effect of all prior 4024 ** [sqlite3_auto_extension()] calls. 4025 ** 4026 ** {H12661} This function disables all previously registered 4027 ** automatic extensions. 4028 ** 4029 ** {H12662} This function disables automatic extensions in all threads. 4030 */ 4031 void sqlite3_reset_auto_extension(void); 4032 4033 /* 4034 ****** EXPERIMENTAL - subject to change without notice ************** 4035 ** 4036 ** The interface to the virtual-table mechanism is currently considered 4037 ** to be experimental. The interface might change in incompatible ways. 4038 ** If this is a problem for you, do not use the interface at this time. 4039 ** 4040 ** When the virtual-table mechanism stabilizes, we will declare the 4041 ** interface fixed, support it indefinitely, and remove this comment. 4042 */ 4043 4044 /* 4045 ** Structures used by the virtual table interface 4046 */ 4047 typedef struct sqlite3_vtab sqlite3_vtab; 4048 typedef struct sqlite3_index_info sqlite3_index_info; 4049 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4050 typedef struct sqlite3_module sqlite3_module; 4051 4052 /* 4053 ** CAPI3REF: Virtual Table Object {H18000} <S20400> 4054 ** KEYWORDS: sqlite3_module 4055 ** EXPERIMENTAL 4056 ** 4057 ** A module is a class of virtual tables. Each module is defined 4058 ** by an instance of the following structure. This structure consists 4059 ** mostly of methods for the module. 4060 ** 4061 ** This interface is experimental and is subject to change or 4062 ** removal in future releases of SQLite. 4063 */ 4064 struct sqlite3_module { 4065 int iVersion; 4066 int (*xCreate)(sqlite3*, void *pAux, 4067 int argc, const char *const*argv, 4068 sqlite3_vtab **ppVTab, char**); 4069 int (*xConnect)(sqlite3*, void *pAux, 4070 int argc, const char *const*argv, 4071 sqlite3_vtab **ppVTab, char**); 4072 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4073 int (*xDisconnect)(sqlite3_vtab *pVTab); 4074 int (*xDestroy)(sqlite3_vtab *pVTab); 4075 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4076 int (*xClose)(sqlite3_vtab_cursor*); 4077 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4078 int argc, sqlite3_value **argv); 4079 int (*xNext)(sqlite3_vtab_cursor*); 4080 int (*xEof)(sqlite3_vtab_cursor*); 4081 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4082 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4083 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4084 int (*xBegin)(sqlite3_vtab *pVTab); 4085 int (*xSync)(sqlite3_vtab *pVTab); 4086 int (*xCommit)(sqlite3_vtab *pVTab); 4087 int (*xRollback)(sqlite3_vtab *pVTab); 4088 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4089 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4090 void **ppArg); 4091 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4092 }; 4093 4094 /* 4095 ** CAPI3REF: Virtual Table Indexing Information {H18100} <S20400> 4096 ** KEYWORDS: sqlite3_index_info 4097 ** EXPERIMENTAL 4098 ** 4099 ** The sqlite3_index_info structure and its substructures is used to 4100 ** pass information into and receive the reply from the xBestIndex 4101 ** method of an sqlite3_module. The fields under **Inputs** are the 4102 ** inputs to xBestIndex and are read-only. xBestIndex inserts its 4103 ** results into the **Outputs** fields. 4104 ** 4105 ** The aConstraint[] array records WHERE clause constraints of the form: 4106 ** 4107 ** <pre>column OP expr</pre> 4108 ** 4109 ** where OP is =, <, <=, >, or >=. The particular operator is 4110 ** stored in aConstraint[].op. The index of the column is stored in 4111 ** aConstraint[].iColumn. aConstraint[].usable is TRUE if the 4112 ** expr on the right-hand side can be evaluated (and thus the constraint 4113 ** is usable) and false if it cannot. 4114 ** 4115 ** The optimizer automatically inverts terms of the form "expr OP column" 4116 ** and makes other simplifications to the WHERE clause in an attempt to 4117 ** get as many WHERE clause terms into the form shown above as possible. 4118 ** The aConstraint[] array only reports WHERE clause terms in the correct 4119 ** form that refer to the particular virtual table being queried. 4120 ** 4121 ** Information about the ORDER BY clause is stored in aOrderBy[]. 4122 ** Each term of aOrderBy records a column of the ORDER BY clause. 4123 ** 4124 ** The xBestIndex method must fill aConstraintUsage[] with information 4125 ** about what parameters to pass to xFilter. If argvIndex>0 then 4126 ** the right-hand side of the corresponding aConstraint[] is evaluated 4127 ** and becomes the argvIndex-th entry in argv. If aConstraintUsage[].omit 4128 ** is true, then the constraint is assumed to be fully handled by the 4129 ** virtual table and is not checked again by SQLite. 4130 ** 4131 ** The idxNum and idxPtr values are recorded and passed into xFilter. 4132 ** sqlite3_free() is used to free idxPtr if needToFreeIdxPtr is true. 4133 ** 4134 ** The orderByConsumed means that output from xFilter will occur in 4135 ** the correct order to satisfy the ORDER BY clause so that no separate 4136 ** sorting step is required. 4137 ** 4138 ** The estimatedCost value is an estimate of the cost of doing the 4139 ** particular lookup. A full scan of a table with N entries should have 4140 ** a cost of N. A binary search of a table of N entries should have a 4141 ** cost of approximately log(N). 4142 ** 4143 ** This interface is experimental and is subject to change or 4144 ** removal in future releases of SQLite. 4145 */ 4146 struct sqlite3_index_info { 4147 /* Inputs */ 4148 int nConstraint; /* Number of entries in aConstraint */ 4149 struct sqlite3_index_constraint { 4150 int iColumn; /* Column on left-hand side of constraint */ 4151 unsigned char op; /* Constraint operator */ 4152 unsigned char usable; /* True if this constraint is usable */ 4153 int iTermOffset; /* Used internally - xBestIndex should ignore */ 4154 } *aConstraint; /* Table of WHERE clause constraints */ 4155 int nOrderBy; /* Number of terms in the ORDER BY clause */ 4156 struct sqlite3_index_orderby { 4157 int iColumn; /* Column number */ 4158 unsigned char desc; /* True for DESC. False for ASC. */ 4159 } *aOrderBy; /* The ORDER BY clause */ 4160 /* Outputs */ 4161 struct sqlite3_index_constraint_usage { 4162 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 4163 unsigned char omit; /* Do not code a test for this constraint */ 4164 } *aConstraintUsage; 4165 int idxNum; /* Number used to identify the index */ 4166 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 4167 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 4168 int orderByConsumed; /* True if output is already ordered */ 4169 double estimatedCost; /* Estimated cost of using this index */ 4170 }; 4171 #define SQLITE_INDEX_CONSTRAINT_EQ 2 4172 #define SQLITE_INDEX_CONSTRAINT_GT 4 4173 #define SQLITE_INDEX_CONSTRAINT_LE 8 4174 #define SQLITE_INDEX_CONSTRAINT_LT 16 4175 #define SQLITE_INDEX_CONSTRAINT_GE 32 4176 #define SQLITE_INDEX_CONSTRAINT_MATCH 64 4177 4178 /* 4179 ** CAPI3REF: Register A Virtual Table Implementation {H18200} <S20400> 4180 ** EXPERIMENTAL 4181 ** 4182 ** This routine is used to register a new module name with a 4183 ** [database connection]. Module names must be registered before 4184 ** creating new virtual tables on the module, or before using 4185 ** preexisting virtual tables of the module. 4186 ** 4187 ** This interface is experimental and is subject to change or 4188 ** removal in future releases of SQLite. 4189 */ 4190 SQLITE_EXPERIMENTAL int sqlite3_create_module( 4191 sqlite3 *db, /* SQLite connection to register module with */ 4192 const char *zName, /* Name of the module */ 4193 const sqlite3_module *, /* Methods for the module */ 4194 void * /* Client data for xCreate/xConnect */ 4195 ); 4196 4197 /* 4198 ** CAPI3REF: Register A Virtual Table Implementation {H18210} <S20400> 4199 ** EXPERIMENTAL 4200 ** 4201 ** This routine is identical to the [sqlite3_create_module()] method above, 4202 ** except that it allows a destructor function to be specified. It is 4203 ** even more experimental than the rest of the virtual tables API. 4204 */ 4205 SQLITE_EXPERIMENTAL int sqlite3_create_module_v2( 4206 sqlite3 *db, /* SQLite connection to register module with */ 4207 const char *zName, /* Name of the module */ 4208 const sqlite3_module *, /* Methods for the module */ 4209 void *, /* Client data for xCreate/xConnect */ 4210 void(*xDestroy)(void*) /* Module destructor function */ 4211 ); 4212 4213 /* 4214 ** CAPI3REF: Virtual Table Instance Object {H18010} <S20400> 4215 ** KEYWORDS: sqlite3_vtab 4216 ** EXPERIMENTAL 4217 ** 4218 ** Every module implementation uses a subclass of the following structure 4219 ** to describe a particular instance of the module. Each subclass will 4220 ** be tailored to the specific needs of the module implementation. 4221 ** The purpose of this superclass is to define certain fields that are 4222 ** common to all module implementations. 4223 ** 4224 ** Virtual tables methods can set an error message by assigning a 4225 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 4226 ** take care that any prior string is freed by a call to [sqlite3_free()] 4227 ** prior to assigning a new string to zErrMsg. After the error message 4228 ** is delivered up to the client application, the string will be automatically 4229 ** freed by sqlite3_free() and the zErrMsg field will be zeroed. Note 4230 ** that sqlite3_mprintf() and sqlite3_free() are used on the zErrMsg field 4231 ** since virtual tables are commonly implemented in loadable extensions which 4232 ** do not have access to sqlite3MPrintf() or sqlite3Free(). 4233 ** 4234 ** This interface is experimental and is subject to change or 4235 ** removal in future releases of SQLite. 4236 */ 4237 struct sqlite3_vtab { 4238 const sqlite3_module *pModule; /* The module for this virtual table */ 4239 int nRef; /* Used internally */ 4240 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 4241 /* Virtual table implementations will typically add additional fields */ 4242 }; 4243 4244 /* 4245 ** CAPI3REF: Virtual Table Cursor Object {H18020} <S20400> 4246 ** KEYWORDS: sqlite3_vtab_cursor 4247 ** EXPERIMENTAL 4248 ** 4249 ** Every module implementation uses a subclass of the following structure 4250 ** to describe cursors that point into the virtual table and are used 4251 ** to loop through the virtual table. Cursors are created using the 4252 ** xOpen method of the module. Each module implementation will define 4253 ** the content of a cursor structure to suit its own needs. 4254 ** 4255 ** This superclass exists in order to define fields of the cursor that 4256 ** are common to all implementations. 4257 ** 4258 ** This interface is experimental and is subject to change or 4259 ** removal in future releases of SQLite. 4260 */ 4261 struct sqlite3_vtab_cursor { 4262 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 4263 /* Virtual table implementations will typically add additional fields */ 4264 }; 4265 4266 /* 4267 ** CAPI3REF: Declare The Schema Of A Virtual Table {H18280} <S20400> 4268 ** EXPERIMENTAL 4269 ** 4270 ** The xCreate and xConnect methods of a module use the following API 4271 ** to declare the format (the names and datatypes of the columns) of 4272 ** the virtual tables they implement. 4273 ** 4274 ** This interface is experimental and is subject to change or 4275 ** removal in future releases of SQLite. 4276 */ 4277 SQLITE_EXPERIMENTAL int sqlite3_declare_vtab(sqlite3*, const char *zCreateTable); 4278 4279 /* 4280 ** CAPI3REF: Overload A Function For A Virtual Table {H18300} <S20400> 4281 ** EXPERIMENTAL 4282 ** 4283 ** Virtual tables can provide alternative implementations of functions 4284 ** using the xFindFunction method. But global versions of those functions 4285 ** must exist in order to be overloaded. 4286 ** 4287 ** This API makes sure a global version of a function with a particular 4288 ** name and number of parameters exists. If no such function exists 4289 ** before this API is called, a new function is created. The implementation 4290 ** of the new function always causes an exception to be thrown. So 4291 ** the new function is not good for anything by itself. Its only 4292 ** purpose is to be a placeholder function that can be overloaded 4293 ** by virtual tables. 4294 ** 4295 ** This API should be considered part of the virtual table interface, 4296 ** which is experimental and subject to change. 4297 */ 4298 SQLITE_EXPERIMENTAL int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 4299 4300 /* 4301 ** The interface to the virtual-table mechanism defined above (back up 4302 ** to a comment remarkably similar to this one) is currently considered 4303 ** to be experimental. The interface might change in incompatible ways. 4304 ** If this is a problem for you, do not use the interface at this time. 4305 ** 4306 ** When the virtual-table mechanism stabilizes, we will declare the 4307 ** interface fixed, support it indefinitely, and remove this comment. 4308 ** 4309 ****** EXPERIMENTAL - subject to change without notice ************** 4310 */ 4311 4312 /* 4313 ** CAPI3REF: A Handle To An Open BLOB {H17800} <S30230> 4314 ** KEYWORDS: {BLOB handle} {BLOB handles} 4315 ** 4316 ** An instance of this object represents an open BLOB on which 4317 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 4318 ** Objects of this type are created by [sqlite3_blob_open()] 4319 ** and destroyed by [sqlite3_blob_close()]. 4320 ** The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 4321 ** can be used to read or write small subsections of the BLOB. 4322 ** The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 4323 */ 4324 typedef struct sqlite3_blob sqlite3_blob; 4325 4326 /* 4327 ** CAPI3REF: Open A BLOB For Incremental I/O {H17810} <S30230> 4328 ** 4329 ** This interfaces opens a [BLOB handle | handle] to the BLOB located 4330 ** in row iRow, column zColumn, table zTable in database zDb; 4331 ** in other words, the same BLOB that would be selected by: 4332 ** 4333 ** <pre> 4334 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 4335 ** </pre> {END} 4336 ** 4337 ** If the flags parameter is non-zero, the the BLOB is opened for read 4338 ** and write access. If it is zero, the BLOB is opened for read access. 4339 ** 4340 ** Note that the database name is not the filename that contains 4341 ** the database but rather the symbolic name of the database that 4342 ** is assigned when the database is connected using [ATTACH]. 4343 ** For the main database file, the database name is "main". 4344 ** For TEMP tables, the database name is "temp". 4345 ** 4346 ** On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 4347 ** to *ppBlob. Otherwise an [error code] is returned and any value written 4348 ** to *ppBlob should not be used by the caller. 4349 ** This function sets the [database connection] error code and message 4350 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()]. 4351 ** 4352 ** If the row that a BLOB handle points to is modified by an 4353 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 4354 ** then the BLOB handle is marked as "expired". 4355 ** This is true if any column of the row is changed, even a column 4356 ** other than the one the BLOB handle is open on. 4357 ** Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 4358 ** a expired BLOB handle fail with an return code of [SQLITE_ABORT]. 4359 ** Changes written into a BLOB prior to the BLOB expiring are not 4360 ** rollback by the expiration of the BLOB. Such changes will eventually 4361 ** commit if the transaction continues to completion. 4362 ** 4363 ** Requirements: 4364 ** [H17813] [H17814] [H17816] [H17819] [H17821] [H17824] 4365 */ 4366 int sqlite3_blob_open( 4367 sqlite3*, 4368 const char *zDb, 4369 const char *zTable, 4370 const char *zColumn, 4371 sqlite3_int64 iRow, 4372 int flags, 4373 sqlite3_blob **ppBlob 4374 ); 4375 4376 /* 4377 ** CAPI3REF: Close A BLOB Handle {H17830} <S30230> 4378 ** 4379 ** Closes an open [BLOB handle]. 4380 ** 4381 ** Closing a BLOB shall cause the current transaction to commit 4382 ** if there are no other BLOBs, no pending prepared statements, and the 4383 ** database connection is in [autocommit mode]. 4384 ** If any writes were made to the BLOB, they might be held in cache 4385 ** until the close operation if they will fit. {END} 4386 ** 4387 ** Closing the BLOB often forces the changes 4388 ** out to disk and so if any I/O errors occur, they will likely occur 4389 ** at the time when the BLOB is closed. {H17833} Any errors that occur during 4390 ** closing are reported as a non-zero return value. 4391 ** 4392 ** The BLOB is closed unconditionally. Even if this routine returns 4393 ** an error code, the BLOB is still closed. 4394 ** 4395 ** Requirements: 4396 ** [H17833] [H17836] [H17839] 4397 */ 4398 int sqlite3_blob_close(sqlite3_blob *); 4399 4400 /* 4401 ** CAPI3REF: Return The Size Of An Open BLOB {H17840} <S30230> 4402 ** 4403 ** Returns the size in bytes of the BLOB accessible via the open 4404 ** []BLOB handle] in its only argument. 4405 ** 4406 ** Requirements: 4407 ** [H17843] 4408 */ 4409 int sqlite3_blob_bytes(sqlite3_blob *); 4410 4411 /* 4412 ** CAPI3REF: Read Data From A BLOB Incrementally {H17850} <S30230> 4413 ** 4414 ** This function is used to read data from an open [BLOB handle] into a 4415 ** caller-supplied buffer. N bytes of data are copied into buffer Z 4416 ** from the open BLOB, starting at offset iOffset. 4417 ** 4418 ** If offset iOffset is less than N bytes from the end of the BLOB, 4419 ** [SQLITE_ERROR] is returned and no data is read. If N or iOffset is 4420 ** less than zero, [SQLITE_ERROR] is returned and no data is read. 4421 ** 4422 ** An attempt to read from an expired [BLOB handle] fails with an 4423 ** error code of [SQLITE_ABORT]. 4424 ** 4425 ** On success, SQLITE_OK is returned. 4426 ** Otherwise, an [error code] or an [extended error code] is returned. 4427 ** 4428 ** Requirements: 4429 ** [H17853] [H17856] [H17859] [H17862] [H17863] [H17865] [H17868] 4430 */ 4431 int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 4432 4433 /* 4434 ** CAPI3REF: Write Data Into A BLOB Incrementally {H17870} <S30230> 4435 ** 4436 ** This function is used to write data into an open [BLOB handle] from a 4437 ** caller-supplied buffer. N bytes of data are copied from the buffer Z 4438 ** into the open BLOB, starting at offset iOffset. 4439 ** 4440 ** If the [BLOB handle] passed as the first argument was not opened for 4441 ** writing (the flags parameter to [sqlite3_blob_open()] was zero), 4442 ** this function returns [SQLITE_READONLY]. 4443 ** 4444 ** This function may only modify the contents of the BLOB; it is 4445 ** not possible to increase the size of a BLOB using this API. 4446 ** If offset iOffset is less than N bytes from the end of the BLOB, 4447 ** [SQLITE_ERROR] is returned and no data is written. If N is 4448 ** less than zero [SQLITE_ERROR] is returned and no data is written. 4449 ** 4450 ** An attempt to write to an expired [BLOB handle] fails with an 4451 ** error code of [SQLITE_ABORT]. Writes to the BLOB that occurred 4452 ** before the [BLOB handle] expired are not rolled back by the 4453 ** expiration of the handle, though of course those changes might 4454 ** have been overwritten by the statement that expired the BLOB handle 4455 ** or by other independent statements. 4456 ** 4457 ** On success, SQLITE_OK is returned. 4458 ** Otherwise, an [error code] or an [extended error code] is returned. 4459 ** 4460 ** Requirements: 4461 ** [H17873] [H17874] [H17875] [H17876] [H17877] [H17879] [H17882] [H17885] 4462 ** [H17888] 4463 */ 4464 int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 4465 4466 /* 4467 ** CAPI3REF: Virtual File System Objects {H11200} <S20100> 4468 ** 4469 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object 4470 ** that SQLite uses to interact 4471 ** with the underlying operating system. Most SQLite builds come with a 4472 ** single default VFS that is appropriate for the host computer. 4473 ** New VFSes can be registered and existing VFSes can be unregistered. 4474 ** The following interfaces are provided. 4475 ** 4476 ** The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 4477 ** Names are case sensitive. 4478 ** Names are zero-terminated UTF-8 strings. 4479 ** If there is no match, a NULL pointer is returned. 4480 ** If zVfsName is NULL then the default VFS is returned. 4481 ** 4482 ** New VFSes are registered with sqlite3_vfs_register(). 4483 ** Each new VFS becomes the default VFS if the makeDflt flag is set. 4484 ** The same VFS can be registered multiple times without injury. 4485 ** To make an existing VFS into the default VFS, register it again 4486 ** with the makeDflt flag set. If two different VFSes with the 4487 ** same name are registered, the behavior is undefined. If a 4488 ** VFS is registered with a name that is NULL or an empty string, 4489 ** then the behavior is undefined. 4490 ** 4491 ** Unregister a VFS with the sqlite3_vfs_unregister() interface. 4492 ** If the default VFS is unregistered, another VFS is chosen as 4493 ** the default. The choice for the new VFS is arbitrary. 4494 ** 4495 ** Requirements: 4496 ** [H11203] [H11206] [H11209] [H11212] [H11215] [H11218] 4497 */ 4498 sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 4499 int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 4500 int sqlite3_vfs_unregister(sqlite3_vfs*); 4501 4502 /* 4503 ** CAPI3REF: Mutexes {H17000} <S20000> 4504 ** 4505 ** The SQLite core uses these routines for thread 4506 ** synchronization. Though they are intended for internal 4507 ** use by SQLite, code that links against SQLite is 4508 ** permitted to use any of these routines. 4509 ** 4510 ** The SQLite source code contains multiple implementations 4511 ** of these mutex routines. An appropriate implementation 4512 ** is selected automatically at compile-time. The following 4513 ** implementations are available in the SQLite core: 4514 ** 4515 ** <ul> 4516 ** <li> SQLITE_MUTEX_OS2 4517 ** <li> SQLITE_MUTEX_PTHREAD 4518 ** <li> SQLITE_MUTEX_W32 4519 ** <li> SQLITE_MUTEX_NOOP 4520 ** </ul> 4521 ** 4522 ** The SQLITE_MUTEX_NOOP implementation is a set of routines 4523 ** that does no real locking and is appropriate for use in 4524 ** a single-threaded application. The SQLITE_MUTEX_OS2, 4525 ** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations 4526 ** are appropriate for use on OS/2, Unix, and Windows. 4527 ** 4528 ** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 4529 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 4530 ** implementation is included with the library. In this case the 4531 ** application must supply a custom mutex implementation using the 4532 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 4533 ** before calling sqlite3_initialize() or any other public sqlite3_ 4534 ** function that calls sqlite3_initialize(). 4535 ** 4536 ** {H17011} The sqlite3_mutex_alloc() routine allocates a new 4537 ** mutex and returns a pointer to it. {H17012} If it returns NULL 4538 ** that means that a mutex could not be allocated. {H17013} SQLite 4539 ** will unwind its stack and return an error. {H17014} The argument 4540 ** to sqlite3_mutex_alloc() is one of these integer constants: 4541 ** 4542 ** <ul> 4543 ** <li> SQLITE_MUTEX_FAST 4544 ** <li> SQLITE_MUTEX_RECURSIVE 4545 ** <li> SQLITE_MUTEX_STATIC_MASTER 4546 ** <li> SQLITE_MUTEX_STATIC_MEM 4547 ** <li> SQLITE_MUTEX_STATIC_MEM2 4548 ** <li> SQLITE_MUTEX_STATIC_PRNG 4549 ** <li> SQLITE_MUTEX_STATIC_LRU 4550 ** <li> SQLITE_MUTEX_STATIC_LRU2 4551 ** </ul> 4552 ** 4553 ** {H17015} The first two constants cause sqlite3_mutex_alloc() to create 4554 ** a new mutex. The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 4555 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used. {END} 4556 ** The mutex implementation does not need to make a distinction 4557 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 4558 ** not want to. {H17016} But SQLite will only request a recursive mutex in 4559 ** cases where it really needs one. {END} If a faster non-recursive mutex 4560 ** implementation is available on the host platform, the mutex subsystem 4561 ** might return such a mutex in response to SQLITE_MUTEX_FAST. 4562 ** 4563 ** {H17017} The other allowed parameters to sqlite3_mutex_alloc() each return 4564 ** a pointer to a static preexisting mutex. {END} Four static mutexes are 4565 ** used by the current version of SQLite. Future versions of SQLite 4566 ** may add additional static mutexes. Static mutexes are for internal 4567 ** use by SQLite only. Applications that use SQLite mutexes should 4568 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 4569 ** SQLITE_MUTEX_RECURSIVE. 4570 ** 4571 ** {H17018} Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 4572 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 4573 ** returns a different mutex on every call. {H17034} But for the static 4574 ** mutex types, the same mutex is returned on every call that has 4575 ** the same type number. 4576 ** 4577 ** {H17019} The sqlite3_mutex_free() routine deallocates a previously 4578 ** allocated dynamic mutex. {H17020} SQLite is careful to deallocate every 4579 ** dynamic mutex that it allocates. {A17021} The dynamic mutexes must not be in 4580 ** use when they are deallocated. {A17022} Attempting to deallocate a static 4581 ** mutex results in undefined behavior. {H17023} SQLite never deallocates 4582 ** a static mutex. {END} 4583 ** 4584 ** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 4585 ** to enter a mutex. {H17024} If another thread is already within the mutex, 4586 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 4587 ** SQLITE_BUSY. {H17025} The sqlite3_mutex_try() interface returns [SQLITE_OK] 4588 ** upon successful entry. {H17026} Mutexes created using 4589 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 4590 ** {H17027} In such cases the, 4591 ** mutex must be exited an equal number of times before another thread 4592 ** can enter. {A17028} If the same thread tries to enter any other 4593 ** kind of mutex more than once, the behavior is undefined. 4594 ** {H17029} SQLite will never exhibit 4595 ** such behavior in its own use of mutexes. 4596 ** 4597 ** Some systems (for example, Windows 95) do not support the operation 4598 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 4599 ** will always return SQLITE_BUSY. {H17030} The SQLite core only ever uses 4600 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior. 4601 ** 4602 ** {H17031} The sqlite3_mutex_leave() routine exits a mutex that was 4603 ** previously entered by the same thread. {A17032} The behavior 4604 ** is undefined if the mutex is not currently entered by the 4605 ** calling thread or is not currently allocated. {H17033} SQLite will 4606 ** never do either. {END} 4607 ** 4608 ** If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 4609 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines 4610 ** behave as no-ops. 4611 ** 4612 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 4613 */ 4614 sqlite3_mutex *sqlite3_mutex_alloc(int); 4615 void sqlite3_mutex_free(sqlite3_mutex*); 4616 void sqlite3_mutex_enter(sqlite3_mutex*); 4617 int sqlite3_mutex_try(sqlite3_mutex*); 4618 void sqlite3_mutex_leave(sqlite3_mutex*); 4619 4620 /* 4621 ** CAPI3REF: Mutex Methods Object {H17120} <S20130> 4622 ** EXPERIMENTAL 4623 ** 4624 ** An instance of this structure defines the low-level routines 4625 ** used to allocate and use mutexes. 4626 ** 4627 ** Usually, the default mutex implementations provided by SQLite are 4628 ** sufficient, however the user has the option of substituting a custom 4629 ** implementation for specialized deployments or systems for which SQLite 4630 ** does not provide a suitable implementation. In this case, the user 4631 ** creates and populates an instance of this structure to pass 4632 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 4633 ** Additionally, an instance of this structure can be used as an 4634 ** output variable when querying the system for the current mutex 4635 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 4636 ** 4637 ** The xMutexInit method defined by this structure is invoked as 4638 ** part of system initialization by the sqlite3_initialize() function. 4639 ** {H17001} The xMutexInit routine shall be called by SQLite once for each 4640 ** effective call to [sqlite3_initialize()]. 4641 ** 4642 ** The xMutexEnd method defined by this structure is invoked as 4643 ** part of system shutdown by the sqlite3_shutdown() function. The 4644 ** implementation of this method is expected to release all outstanding 4645 ** resources obtained by the mutex methods implementation, especially 4646 ** those obtained by the xMutexInit method. {H17003} The xMutexEnd() 4647 ** interface shall be invoked once for each call to [sqlite3_shutdown()]. 4648 ** 4649 ** The remaining seven methods defined by this structure (xMutexAlloc, 4650 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 4651 ** xMutexNotheld) implement the following interfaces (respectively): 4652 ** 4653 ** <ul> 4654 ** <li> [sqlite3_mutex_alloc()] </li> 4655 ** <li> [sqlite3_mutex_free()] </li> 4656 ** <li> [sqlite3_mutex_enter()] </li> 4657 ** <li> [sqlite3_mutex_try()] </li> 4658 ** <li> [sqlite3_mutex_leave()] </li> 4659 ** <li> [sqlite3_mutex_held()] </li> 4660 ** <li> [sqlite3_mutex_notheld()] </li> 4661 ** </ul> 4662 ** 4663 ** The only difference is that the public sqlite3_XXX functions enumerated 4664 ** above silently ignore any invocations that pass a NULL pointer instead 4665 ** of a valid mutex handle. The implementations of the methods defined 4666 ** by this structure are not required to handle this case, the results 4667 ** of passing a NULL pointer instead of a valid mutex handle are undefined 4668 ** (i.e. it is acceptable to provide an implementation that segfaults if 4669 ** it is passed a NULL pointer). 4670 */ 4671 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 4672 struct sqlite3_mutex_methods { 4673 int (*xMutexInit)(void); 4674 int (*xMutexEnd)(void); 4675 sqlite3_mutex *(*xMutexAlloc)(int); 4676 void (*xMutexFree)(sqlite3_mutex *); 4677 void (*xMutexEnter)(sqlite3_mutex *); 4678 int (*xMutexTry)(sqlite3_mutex *); 4679 void (*xMutexLeave)(sqlite3_mutex *); 4680 int (*xMutexHeld)(sqlite3_mutex *); 4681 int (*xMutexNotheld)(sqlite3_mutex *); 4682 }; 4683 4684 /* 4685 ** CAPI3REF: Mutex Verification Routines {H17080} <S20130> <S30800> 4686 ** 4687 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 4688 ** are intended for use inside assert() statements. {H17081} The SQLite core 4689 ** never uses these routines except inside an assert() and applications 4690 ** are advised to follow the lead of the core. {H17082} The core only 4691 ** provides implementations for these routines when it is compiled 4692 ** with the SQLITE_DEBUG flag. {A17087} External mutex implementations 4693 ** are only required to provide these routines if SQLITE_DEBUG is 4694 ** defined and if NDEBUG is not defined. 4695 ** 4696 ** {H17083} These routines should return true if the mutex in their argument 4697 ** is held or not held, respectively, by the calling thread. 4698 ** 4699 ** {X17084} The implementation is not required to provided versions of these 4700 ** routines that actually work. If the implementation does not provide working 4701 ** versions of these routines, it should at least provide stubs that always 4702 ** return true so that one does not get spurious assertion failures. 4703 ** 4704 ** {H17085} If the argument to sqlite3_mutex_held() is a NULL pointer then 4705 ** the routine should return 1. {END} This seems counter-intuitive since 4706 ** clearly the mutex cannot be held if it does not exist. But the 4707 ** the reason the mutex does not exist is because the build is not 4708 ** using mutexes. And we do not want the assert() containing the 4709 ** call to sqlite3_mutex_held() to fail, so a non-zero return is 4710 ** the appropriate thing to do. {H17086} The sqlite3_mutex_notheld() 4711 ** interface should also return 1 when given a NULL pointer. 4712 */ 4713 int sqlite3_mutex_held(sqlite3_mutex*); 4714 int sqlite3_mutex_notheld(sqlite3_mutex*); 4715 4716 /* 4717 ** CAPI3REF: Mutex Types {H17001} <H17000> 4718 ** 4719 ** The [sqlite3_mutex_alloc()] interface takes a single argument 4720 ** which is one of these integer constants. 4721 ** 4722 ** The set of static mutexes may change from one SQLite release to the 4723 ** next. Applications that override the built-in mutex logic must be 4724 ** prepared to accommodate additional static mutexes. 4725 */ 4726 #define SQLITE_MUTEX_FAST 0 4727 #define SQLITE_MUTEX_RECURSIVE 1 4728 #define SQLITE_MUTEX_STATIC_MASTER 2 4729 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 4730 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 4731 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 4732 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 4733 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 4734 #define SQLITE_MUTEX_STATIC_LRU2 7 /* lru page list */ 4735 4736 /* 4737 ** CAPI3REF: Retrieve the mutex for a database connection {H17002} <H17000> 4738 ** 4739 ** This interface returns a pointer the [sqlite3_mutex] object that 4740 ** serializes access to the [database connection] given in the argument 4741 ** when the [threading mode] is Serialized. 4742 ** If the [threading mode] is Single-thread or Multi-thread then this 4743 ** routine returns a NULL pointer. 4744 */ 4745 sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 4746 4747 /* 4748 ** CAPI3REF: Low-Level Control Of Database Files {H11300} <S30800> 4749 ** 4750 ** {H11301} The [sqlite3_file_control()] interface makes a direct call to the 4751 ** xFileControl method for the [sqlite3_io_methods] object associated 4752 ** with a particular database identified by the second argument. {H11302} The 4753 ** name of the database is the name assigned to the database by the 4754 ** <a href="lang_attach.html">ATTACH</a> SQL command that opened the 4755 ** database. {H11303} To control the main database file, use the name "main" 4756 ** or a NULL pointer. {H11304} The third and fourth parameters to this routine 4757 ** are passed directly through to the second and third parameters of 4758 ** the xFileControl method. {H11305} The return value of the xFileControl 4759 ** method becomes the return value of this routine. 4760 ** 4761 ** {H11306} If the second parameter (zDbName) does not match the name of any 4762 ** open database file, then SQLITE_ERROR is returned. {H11307} This error 4763 ** code is not remembered and will not be recalled by [sqlite3_errcode()] 4764 ** or [sqlite3_errmsg()]. {A11308} The underlying xFileControl method might 4765 ** also return SQLITE_ERROR. {A11309} There is no way to distinguish between 4766 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying 4767 ** xFileControl method. {END} 4768 ** 4769 ** See also: [SQLITE_FCNTL_LOCKSTATE] 4770 */ 4771 int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 4772 4773 /* 4774 ** CAPI3REF: Testing Interface {H11400} <S30800> 4775 ** 4776 ** The sqlite3_test_control() interface is used to read out internal 4777 ** state of SQLite and to inject faults into SQLite for testing 4778 ** purposes. The first parameter is an operation code that determines 4779 ** the number, meaning, and operation of all subsequent parameters. 4780 ** 4781 ** This interface is not for use by applications. It exists solely 4782 ** for verifying the correct operation of the SQLite library. Depending 4783 ** on how the SQLite library is compiled, this interface might not exist. 4784 ** 4785 ** The details of the operation codes, their meanings, the parameters 4786 ** they take, and what they do are all subject to change without notice. 4787 ** Unlike most of the SQLite API, this function is not guaranteed to 4788 ** operate consistently from one release to the next. 4789 */ 4790 int sqlite3_test_control(int op, ...); 4791 4792 /* 4793 ** CAPI3REF: Testing Interface Operation Codes {H11410} <H11400> 4794 ** 4795 ** These constants are the valid operation code parameters used 4796 ** as the first argument to [sqlite3_test_control()]. 4797 ** 4798 ** These parameters and their meanings are subject to change 4799 ** without notice. These values are for testing purposes only. 4800 ** Applications should not use any of these parameters or the 4801 ** [sqlite3_test_control()] interface. 4802 */ 4803 #define SQLITE_TESTCTRL_PRNG_SAVE 5 4804 #define SQLITE_TESTCTRL_PRNG_RESTORE 6 4805 #define SQLITE_TESTCTRL_PRNG_RESET 7 4806 #define SQLITE_TESTCTRL_BITVEC_TEST 8 4807 #define SQLITE_TESTCTRL_FAULT_INSTALL 9 4808 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 4809 #define SQLITE_TESTCTRL_PENDING_BYTE 11 4810 4811 /* 4812 ** CAPI3REF: SQLite Runtime Status {H17200} <S60200> 4813 ** EXPERIMENTAL 4814 ** 4815 ** This interface is used to retrieve runtime status information 4816 ** about the preformance of SQLite, and optionally to reset various 4817 ** highwater marks. The first argument is an integer code for 4818 ** the specific parameter to measure. Recognized integer codes 4819 ** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...]. 4820 ** The current value of the parameter is returned into *pCurrent. 4821 ** The highest recorded value is returned in *pHighwater. If the 4822 ** resetFlag is true, then the highest record value is reset after 4823 ** *pHighwater is written. Some parameters do not record the highest 4824 ** value. For those parameters 4825 ** nothing is written into *pHighwater and the resetFlag is ignored. 4826 ** Other parameters record only the highwater mark and not the current 4827 ** value. For these latter parameters nothing is written into *pCurrent. 4828 ** 4829 ** This routine returns SQLITE_OK on success and a non-zero 4830 ** [error code] on failure. 4831 ** 4832 ** This routine is threadsafe but is not atomic. This routine can 4833 ** called while other threads are running the same or different SQLite 4834 ** interfaces. However the values returned in *pCurrent and 4835 ** *pHighwater reflect the status of SQLite at different points in time 4836 ** and it is possible that another thread might change the parameter 4837 ** in between the times when *pCurrent and *pHighwater are written. 4838 ** 4839 ** See also: [sqlite3_db_status()] 4840 */ 4841 SQLITE_EXPERIMENTAL int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 4842 4843 4844 /* 4845 ** CAPI3REF: Status Parameters {H17250} <H17200> 4846 ** EXPERIMENTAL 4847 ** 4848 ** These integer constants designate various run-time status parameters 4849 ** that can be returned by [sqlite3_status()]. 4850 ** 4851 ** <dl> 4852 ** <dt>SQLITE_STATUS_MEMORY_USED</dt> 4853 ** <dd>This parameter is the current amount of memory checked out 4854 ** using [sqlite3_malloc()], either directly or indirectly. The 4855 ** figure includes calls made to [sqlite3_malloc()] by the application 4856 ** and internal memory usage by the SQLite library. Scratch memory 4857 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 4858 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 4859 ** this parameter. The amount returned is the sum of the allocation 4860 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd> 4861 ** 4862 ** <dt>SQLITE_STATUS_MALLOC_SIZE</dt> 4863 ** <dd>This parameter records the largest memory allocation request 4864 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 4865 ** internal equivalents). Only the value returned in the 4866 ** *pHighwater parameter to [sqlite3_status()] is of interest. 4867 ** The value written into the *pCurrent parameter is undefined.</dd> 4868 ** 4869 ** <dt>SQLITE_STATUS_PAGECACHE_USED</dt> 4870 ** <dd>This parameter returns the number of pages used out of the 4871 ** [pagecache memory allocator] that was configured using 4872 ** [SQLITE_CONFIG_PAGECACHE]. The 4873 ** value returned is in pages, not in bytes.</dd> 4874 ** 4875 ** <dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 4876 ** <dd>This parameter returns the number of bytes of page cache 4877 ** allocation which could not be statisfied by the [SQLITE_CONFIG_PAGECACHE] 4878 ** buffer and where forced to overflow to [sqlite3_malloc()]. The 4879 ** returned value includes allocations that overflowed because they 4880 ** where too large (they were larger than the "sz" parameter to 4881 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 4882 ** no space was left in the page cache.</dd> 4883 ** 4884 ** <dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 4885 ** <dd>This parameter records the largest memory allocation request 4886 ** handed to [pagecache memory allocator]. Only the value returned in the 4887 ** *pHighwater parameter to [sqlite3_status()] is of interest. 4888 ** The value written into the *pCurrent parameter is undefined.</dd> 4889 ** 4890 ** <dt>SQLITE_STATUS_SCRATCH_USED</dt> 4891 ** <dd>This parameter returns the number of allocations used out of the 4892 ** [scratch memory allocator] configured using 4893 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 4894 ** in bytes. Since a single thread may only have one scratch allocation 4895 ** outstanding at time, this parameter also reports the number of threads 4896 ** using scratch memory at the same time.</dd> 4897 ** 4898 ** <dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 4899 ** <dd>This parameter returns the number of bytes of scratch memory 4900 ** allocation which could not be statisfied by the [SQLITE_CONFIG_SCRATCH] 4901 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values 4902 ** returned include overflows because the requested allocation was too 4903 ** larger (that is, because the requested allocation was larger than the 4904 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 4905 ** slots were available. 4906 ** </dd> 4907 ** 4908 ** <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 4909 ** <dd>This parameter records the largest memory allocation request 4910 ** handed to [scratch memory allocator]. Only the value returned in the 4911 ** *pHighwater parameter to [sqlite3_status()] is of interest. 4912 ** The value written into the *pCurrent parameter is undefined.</dd> 4913 ** 4914 ** <dt>SQLITE_STATUS_PARSER_STACK</dt> 4915 ** <dd>This parameter records the deepest parser stack. It is only 4916 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd> 4917 ** </dl> 4918 ** 4919 ** New status parameters may be added from time to time. 4920 */ 4921 #define SQLITE_STATUS_MEMORY_USED 0 4922 #define SQLITE_STATUS_PAGECACHE_USED 1 4923 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 4924 #define SQLITE_STATUS_SCRATCH_USED 3 4925 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4 4926 #define SQLITE_STATUS_MALLOC_SIZE 5 4927 #define SQLITE_STATUS_PARSER_STACK 6 4928 #define SQLITE_STATUS_PAGECACHE_SIZE 7 4929 #define SQLITE_STATUS_SCRATCH_SIZE 8 4930 4931 /* 4932 ** CAPI3REF: Database Connection Status {H17500} <S60200> 4933 ** EXPERIMENTAL 4934 ** 4935 ** This interface is used to retrieve runtime status information 4936 ** about a single [database connection]. The first argument is the 4937 ** database connection object to be interrogated. The second argument 4938 ** is the parameter to interrogate. Currently, the only allowed value 4939 ** for the second parameter is [SQLITE_DBSTATUS_LOOKASIDE_USED]. 4940 ** Additional options will likely appear in future releases of SQLite. 4941 ** 4942 ** The current value of the requested parameter is written into *pCur 4943 ** and the highest instantaneous value is written into *pHiwtr. If 4944 ** the resetFlg is true, then the highest instantaneous value is 4945 ** reset back down to the current value. 4946 ** 4947 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 4948 */ 4949 SQLITE_EXPERIMENTAL int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 4950 4951 /* 4952 ** CAPI3REF: Status Parameters for database connections {H17520} <H17500> 4953 ** EXPERIMENTAL 4954 ** 4955 ** Status verbs for [sqlite3_db_status()]. 4956 ** 4957 ** <dl> 4958 ** <dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 4959 ** <dd>This parameter returns the number of lookaside memory slots currently 4960 ** checked out.</dd> 4961 ** </dl> 4962 */ 4963 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0 4964 4965 4966 /* 4967 ** CAPI3REF: Prepared Statement Status {H17550} <S60200> 4968 ** EXPERIMENTAL 4969 ** 4970 ** Each prepared statement maintains various 4971 ** [SQLITE_STMTSTATUS_SORT | counters] that measure the number 4972 ** of times it has performed specific operations. These counters can 4973 ** be used to monitor the performance characteristics of the prepared 4974 ** statements. For example, if the number of table steps greatly exceeds 4975 ** the number of table searches or result rows, that would tend to indicate 4976 ** that the prepared statement is using a full table scan rather than 4977 ** an index. 4978 ** 4979 ** This interface is used to retrieve and reset counter values from 4980 ** a [prepared statement]. The first argument is the prepared statement 4981 ** object to be interrogated. The second argument 4982 ** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter] 4983 ** to be interrogated. 4984 ** The current value of the requested counter is returned. 4985 ** If the resetFlg is true, then the counter is reset to zero after this 4986 ** interface call returns. 4987 ** 4988 ** See also: [sqlite3_status()] and [sqlite3_db_status()]. 4989 */ 4990 SQLITE_EXPERIMENTAL int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 4991 4992 /* 4993 ** CAPI3REF: Status Parameters for prepared statements {H17570} <H17550> 4994 ** EXPERIMENTAL 4995 ** 4996 ** These preprocessor macros define integer codes that name counter 4997 ** values associated with the [sqlite3_stmt_status()] interface. 4998 ** The meanings of the various counters are as follows: 4999 ** 5000 ** <dl> 5001 ** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 5002 ** <dd>This is the number of times that SQLite has stepped forward in 5003 ** a table as part of a full table scan. Large numbers for this counter 5004 ** may indicate opportunities for performance improvement through 5005 ** careful use of indices.</dd> 5006 ** 5007 ** <dt>SQLITE_STMTSTATUS_SORT</dt> 5008 ** <dd>This is the number of sort operations that have occurred. 5009 ** A non-zero value in this counter may indicate an opportunity to 5010 ** improvement performance through careful use of indices.</dd> 5011 ** 5012 ** </dl> 5013 */ 5014 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 5015 #define SQLITE_STMTSTATUS_SORT 2 5016 5017 /* 5018 ** CAPI3REF: Custom Page Cache Object 5019 ** EXPERIMENTAL 5020 ** 5021 ** The sqlite3_pcache type is opaque. It is implemented by 5022 ** the pluggable module. The SQLite core has no knowledge of 5023 ** its size or internal structure and never deals with the 5024 ** sqlite3_pcache object except by holding and passing pointers 5025 ** to the object. 5026 ** 5027 ** See [sqlite3_pcache_methods] for additional information. 5028 */ 5029 typedef struct sqlite3_pcache sqlite3_pcache; 5030 5031 /* 5032 ** CAPI3REF: Application Defined Page Cache. 5033 ** EXPERIMENTAL 5034 ** 5035 ** The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can 5036 ** register an alternative page cache implementation by passing in an 5037 ** instance of the sqlite3_pcache_methods structure. The majority of the 5038 ** heap memory used by sqlite is used by the page cache to cache data read 5039 ** from, or ready to be written to, the database file. By implementing a 5040 ** custom page cache using this API, an application can control more 5041 ** precisely the amount of memory consumed by sqlite, the way in which 5042 ** said memory is allocated and released, and the policies used to 5043 ** determine exactly which parts of a database file are cached and for 5044 ** how long. 5045 ** 5046 ** The contents of the structure are copied to an internal buffer by sqlite 5047 ** within the call to [sqlite3_config]. 5048 ** 5049 ** The xInit() method is called once for each call to [sqlite3_initialize()] 5050 ** (usually only once during the lifetime of the process). It is passed 5051 ** a copy of the sqlite3_pcache_methods.pArg value. It can be used to set 5052 ** up global structures and mutexes required by the custom page cache 5053 ** implementation. The xShutdown() method is called from within 5054 ** [sqlite3_shutdown()], if the application invokes this API. It can be used 5055 ** to clean up any outstanding resources before process shutdown, if required. 5056 ** 5057 ** The xCreate() method is used to construct a new cache instance. The 5058 ** first parameter, szPage, is the size in bytes of the pages that must 5059 ** be allocated by the cache. szPage will not be a power of two. The 5060 ** second argument, bPurgeable, is true if the cache being created will 5061 ** be used to cache database pages read from a file stored on disk, or 5062 ** false if it is used for an in-memory database. The cache implementation 5063 ** does not have to do anything special based on the value of bPurgeable, 5064 ** it is purely advisory. 5065 ** 5066 ** The xCachesize() method may be called at any time by SQLite to set the 5067 ** suggested maximum cache-size (number of pages stored by) the cache 5068 ** instance passed as the first argument. This is the value configured using 5069 ** the SQLite "[PRAGMA cache_size]" command. As with the bPurgeable parameter, 5070 ** the implementation is not required to do anything special with this 5071 ** value, it is advisory only. 5072 ** 5073 ** The xPagecount() method should return the number of pages currently 5074 ** stored in the cache supplied as an argument. 5075 ** 5076 ** The xFetch() method is used to fetch a page and return a pointer to it. 5077 ** A 'page', in this context, is a buffer of szPage bytes aligned at an 5078 ** 8-byte boundary. The page to be fetched is determined by the key. The 5079 ** mimimum key value is 1. After it has been retrieved using xFetch, the page 5080 ** is considered to be pinned. 5081 ** 5082 ** If the requested page is already in the page cache, then a pointer to 5083 ** the cached buffer should be returned with its contents intact. If the 5084 ** page is not already in the cache, then the expected behaviour of the 5085 ** cache is determined by the value of the createFlag parameter passed 5086 ** to xFetch, according to the following table: 5087 ** 5088 ** <table border=1 width=85% align=center> 5089 ** <tr><th>createFlag<th>Expected Behaviour 5090 ** <tr><td>0<td>NULL should be returned. No new cache entry is created. 5091 ** <tr><td>1<td>If createFlag is set to 1, this indicates that 5092 ** SQLite is holding pinned pages that can be unpinned 5093 ** by writing their contents to the database file (a 5094 ** relatively expensive operation). In this situation the 5095 ** cache implementation has two choices: it can return NULL, 5096 ** in which case SQLite will attempt to unpin one or more 5097 ** pages before re-requesting the same page, or it can 5098 ** allocate a new page and return a pointer to it. If a new 5099 ** page is allocated, then the first sizeof(void*) bytes of 5100 ** it (at least) must be zeroed before it is returned. 5101 ** <tr><td>2<td>If createFlag is set to 2, then SQLite is not holding any 5102 ** pinned pages associated with the specific cache passed 5103 ** as the first argument to xFetch() that can be unpinned. The 5104 ** cache implementation should attempt to allocate a new 5105 ** cache entry and return a pointer to it. Again, the first 5106 ** sizeof(void*) bytes of the page should be zeroed before 5107 ** it is returned. If the xFetch() method returns NULL when 5108 ** createFlag==2, SQLite assumes that a memory allocation 5109 ** failed and returns SQLITE_NOMEM to the user. 5110 ** </table> 5111 ** 5112 ** xUnpin() is called by SQLite with a pointer to a currently pinned page 5113 ** as its second argument. If the third parameter, discard, is non-zero, 5114 ** then the page should be evicted from the cache. In this case SQLite 5115 ** assumes that the next time the page is retrieved from the cache using 5116 ** the xFetch() method, it will be zeroed. If the discard parameter is 5117 ** zero, then the page is considered to be unpinned. The cache implementation 5118 ** may choose to reclaim (free or recycle) unpinned pages at any time. 5119 ** SQLite assumes that next time the page is retrieved from the cache 5120 ** it will either be zeroed, or contain the same data that it did when it 5121 ** was unpinned. 5122 ** 5123 ** The cache is not required to perform any reference counting. A single 5124 ** call to xUnpin() unpins the page regardless of the number of prior calls 5125 ** to xFetch(). 5126 ** 5127 ** The xRekey() method is used to change the key value associated with the 5128 ** page passed as the second argument from oldKey to newKey. If the cache 5129 ** previously contains an entry associated with newKey, it should be 5130 ** discarded. Any prior cache entry associated with newKey is guaranteed not 5131 ** to be pinned. 5132 ** 5133 ** When SQLite calls the xTruncate() method, the cache must discard all 5134 ** existing cache entries with page numbers (keys) greater than or equal 5135 ** to the value of the iLimit parameter passed to xTruncate(). If any 5136 ** of these pages are pinned, they are implicitly unpinned, meaning that 5137 ** they can be safely discarded. 5138 ** 5139 ** The xDestroy() method is used to delete a cache allocated by xCreate(). 5140 ** All resources associated with the specified cache should be freed. After 5141 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 5142 ** handle invalid, and will not use it with any other sqlite3_pcache_methods 5143 ** functions. 5144 */ 5145 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 5146 struct sqlite3_pcache_methods { 5147 void *pArg; 5148 int (*xInit)(void*); 5149 void (*xShutdown)(void*); 5150 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 5151 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 5152 int (*xPagecount)(sqlite3_pcache*); 5153 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 5154 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 5155 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 5156 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 5157 void (*xDestroy)(sqlite3_pcache*); 5158 }; 5159 5160 /* 5161 ** CAPI3REF: Online Backup Object 5162 ** EXPERIMENTAL 5163 ** 5164 ** The sqlite3_backup object records state information about an ongoing 5165 ** online backup operation. The sqlite3_backup object is created by 5166 ** a call to [sqlite3_backup_init()] and is destroyed by a call to 5167 ** [sqlite3_backup_finish()]. 5168 ** 5169 ** See Also: [Using the SQLite Online Backup API] 5170 */ 5171 typedef struct sqlite3_backup sqlite3_backup; 5172 5173 /* 5174 ** CAPI3REF: Online Backup API. 5175 ** EXPERIMENTAL 5176 ** 5177 ** This API is used to overwrite the contents of one database with that 5178 ** of another. It is useful either for creating backups of databases or 5179 ** for copying in-memory databases to or from persistent files. 5180 ** 5181 ** See Also: [Using the SQLite Online Backup API] 5182 ** 5183 ** Exclusive access is required to the destination database for the 5184 ** duration of the operation. However the source database is only 5185 ** read-locked while it is actually being read, it is not locked 5186 ** continuously for the entire operation. Thus, the backup may be 5187 ** performed on a live database without preventing other users from 5188 ** writing to the database for an extended period of time. 5189 ** 5190 ** To perform a backup operation: 5191 ** <ol> 5192 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the 5193 ** backup, 5194 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 5195 ** the data between the two databases, and finally 5196 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources 5197 ** associated with the backup operation. 5198 ** </ol> 5199 ** There should be exactly one call to sqlite3_backup_finish() for each 5200 ** successful call to sqlite3_backup_init(). 5201 ** 5202 ** <b>sqlite3_backup_init()</b> 5203 ** 5204 ** The first two arguments passed to [sqlite3_backup_init()] are the database 5205 ** handle associated with the destination database and the database name 5206 ** used to attach the destination database to the handle. The database name 5207 ** is "main" for the main database, "temp" for the temporary database, or 5208 ** the name specified as part of the [ATTACH] statement if the destination is 5209 ** an attached database. The third and fourth arguments passed to 5210 ** sqlite3_backup_init() identify the [database connection] 5211 ** and database name used 5212 ** to access the source database. The values passed for the source and 5213 ** destination [database connection] parameters must not be the same. 5214 ** 5215 ** If an error occurs within sqlite3_backup_init(), then NULL is returned 5216 ** and an error code and error message written into the [database connection] 5217 ** passed as the first argument. They may be retrieved using the 5218 ** [sqlite3_errcode()], [sqlite3_errmsg()], and [sqlite3_errmsg16()] functions. 5219 ** Otherwise, if successful, a pointer to an [sqlite3_backup] object is 5220 ** returned. This pointer may be used with the sqlite3_backup_step() and 5221 ** sqlite3_backup_finish() functions to perform the specified backup 5222 ** operation. 5223 ** 5224 ** <b>sqlite3_backup_step()</b> 5225 ** 5226 ** Function [sqlite3_backup_step()] is used to copy up to nPage pages between 5227 ** the source and destination databases, where nPage is the value of the 5228 ** second parameter passed to sqlite3_backup_step(). If nPage is a negative 5229 ** value, all remaining source pages are copied. If the required pages are 5230 ** succesfully copied, but there are still more pages to copy before the 5231 ** backup is complete, it returns [SQLITE_OK]. If no error occured and there 5232 ** are no more pages to copy, then [SQLITE_DONE] is returned. If an error 5233 ** occurs, then an SQLite error code is returned. As well as [SQLITE_OK] and 5234 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 5235 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 5236 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 5237 ** 5238 ** As well as the case where the destination database file was opened for 5239 ** read-only access, sqlite3_backup_step() may return [SQLITE_READONLY] if 5240 ** the destination is an in-memory database with a different page size 5241 ** from the source database. 5242 ** 5243 ** If sqlite3_backup_step() cannot obtain a required file-system lock, then 5244 ** the [sqlite3_busy_handler | busy-handler function] 5245 ** is invoked (if one is specified). If the 5246 ** busy-handler returns non-zero before the lock is available, then 5247 ** [SQLITE_BUSY] is returned to the caller. In this case the call to 5248 ** sqlite3_backup_step() can be retried later. If the source 5249 ** [database connection] 5250 ** is being used to write to the source database when sqlite3_backup_step() 5251 ** is called, then [SQLITE_LOCKED] is returned immediately. Again, in this 5252 ** case the call to sqlite3_backup_step() can be retried later on. If 5253 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 5254 ** [SQLITE_READONLY] is returned, then 5255 ** there is no point in retrying the call to sqlite3_backup_step(). These 5256 ** errors are considered fatal. At this point the application must accept 5257 ** that the backup operation has failed and pass the backup operation handle 5258 ** to the sqlite3_backup_finish() to release associated resources. 5259 ** 5260 ** Following the first call to sqlite3_backup_step(), an exclusive lock is 5261 ** obtained on the destination file. It is not released until either 5262 ** sqlite3_backup_finish() is called or the backup operation is complete 5263 ** and sqlite3_backup_step() returns [SQLITE_DONE]. Additionally, each time 5264 ** a call to sqlite3_backup_step() is made a [shared lock] is obtained on 5265 ** the source database file. This lock is released before the 5266 ** sqlite3_backup_step() call returns. Because the source database is not 5267 ** locked between calls to sqlite3_backup_step(), it may be modified mid-way 5268 ** through the backup procedure. If the source database is modified by an 5269 ** external process or via a database connection other than the one being 5270 ** used by the backup operation, then the backup will be transparently 5271 ** restarted by the next call to sqlite3_backup_step(). If the source 5272 ** database is modified by the using the same database connection as is used 5273 ** by the backup operation, then the backup database is transparently 5274 ** updated at the same time. 5275 ** 5276 ** <b>sqlite3_backup_finish()</b> 5277 ** 5278 ** Once sqlite3_backup_step() has returned [SQLITE_DONE], or when the 5279 ** application wishes to abandon the backup operation, the [sqlite3_backup] 5280 ** object should be passed to sqlite3_backup_finish(). This releases all 5281 ** resources associated with the backup operation. If sqlite3_backup_step() 5282 ** has not yet returned [SQLITE_DONE], then any active write-transaction on the 5283 ** destination database is rolled back. The [sqlite3_backup] object is invalid 5284 ** and may not be used following a call to sqlite3_backup_finish(). 5285 ** 5286 ** The value returned by sqlite3_backup_finish is [SQLITE_OK] if no error 5287 ** occurred, regardless or whether or not sqlite3_backup_step() was called 5288 ** a sufficient number of times to complete the backup operation. Or, if 5289 ** an out-of-memory condition or IO error occured during a call to 5290 ** sqlite3_backup_step() then [SQLITE_NOMEM] or an 5291 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] error code 5292 ** is returned. In this case the error code and an error message are 5293 ** written to the destination [database connection]. 5294 ** 5295 ** A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() is 5296 ** not a permanent error and does not affect the return value of 5297 ** sqlite3_backup_finish(). 5298 ** 5299 ** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b> 5300 ** 5301 ** Each call to sqlite3_backup_step() sets two values stored internally 5302 ** by an [sqlite3_backup] object. The number of pages still to be backed 5303 ** up, which may be queried by sqlite3_backup_remaining(), and the total 5304 ** number of pages in the source database file, which may be queried by 5305 ** sqlite3_backup_pagecount(). 5306 ** 5307 ** The values returned by these functions are only updated by 5308 ** sqlite3_backup_step(). If the source database is modified during a backup 5309 ** operation, then the values are not updated to account for any extra 5310 ** pages that need to be updated or the size of the source database file 5311 ** changing. 5312 ** 5313 ** <b>Concurrent Usage of Database Handles</b> 5314 ** 5315 ** The source [database connection] may be used by the application for other 5316 ** purposes while a backup operation is underway or being initialized. 5317 ** If SQLite is compiled and configured to support threadsafe database 5318 ** connections, then the source database connection may be used concurrently 5319 ** from within other threads. 5320 ** 5321 ** However, the application must guarantee that the destination database 5322 ** connection handle is not passed to any other API (by any thread) after 5323 ** sqlite3_backup_init() is called and before the corresponding call to 5324 ** sqlite3_backup_finish(). Unfortunately SQLite does not currently check 5325 ** for this, if the application does use the destination [database connection] 5326 ** for some other purpose during a backup operation, things may appear to 5327 ** work correctly but in fact be subtly malfunctioning. Use of the 5328 ** destination database connection while a backup is in progress might 5329 ** also cause a mutex deadlock. 5330 ** 5331 ** Furthermore, if running in [shared cache mode], the application must 5332 ** guarantee that the shared cache used by the destination database 5333 ** is not accessed while the backup is running. In practice this means 5334 ** that the application must guarantee that the file-system file being 5335 ** backed up to is not accessed by any connection within the process, 5336 ** not just the specific connection that was passed to sqlite3_backup_init(). 5337 ** 5338 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple 5339 ** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 5340 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 5341 ** APIs are not strictly speaking threadsafe. If they are invoked at the 5342 ** same time as another thread is invoking sqlite3_backup_step() it is 5343 ** possible that they return invalid values. 5344 */ 5345 sqlite3_backup *sqlite3_backup_init( 5346 sqlite3 *pDest, /* Destination database handle */ 5347 const char *zDestName, /* Destination database name */ 5348 sqlite3 *pSource, /* Source database handle */ 5349 const char *zSourceName /* Source database name */ 5350 ); 5351 int sqlite3_backup_step(sqlite3_backup *p, int nPage); 5352 int sqlite3_backup_finish(sqlite3_backup *p); 5353 int sqlite3_backup_remaining(sqlite3_backup *p); 5354 int sqlite3_backup_pagecount(sqlite3_backup *p); 5355 5356 /* 5357 ** CAPI3REF: Unlock Notification 5358 ** EXPERIMENTAL 5359 ** 5360 ** When running in shared-cache mode, a database operation may fail with 5361 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 5362 ** individual tables within the shared-cache cannot be obtained. See 5363 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 5364 ** This API may be used to register a callback that SQLite will invoke 5365 ** when the connection currently holding the required lock relinquishes it. 5366 ** This API is only available if the library was compiled with the 5367 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 5368 ** 5369 ** See Also: [Using the SQLite Unlock Notification Feature]. 5370 ** 5371 ** Shared-cache locks are released when a database connection concludes 5372 ** its current transaction, either by committing it or rolling it back. 5373 ** 5374 ** When a connection (known as the blocked connection) fails to obtain a 5375 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 5376 ** identity of the database connection (the blocking connection) that 5377 ** has locked the required resource is stored internally. After an 5378 ** application receives an SQLITE_LOCKED error, it may call the 5379 ** sqlite3_unlock_notify() method with the blocked connection handle as 5380 ** the first argument to register for a callback that will be invoked 5381 ** when the blocking connections current transaction is concluded. The 5382 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 5383 ** call that concludes the blocking connections transaction. 5384 ** 5385 ** If sqlite3_unlock_notify() is called in a multi-threaded application, 5386 ** there is a chance that the blocking connection will have already 5387 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 5388 ** If this happens, then the specified callback is invoked immediately, 5389 ** from within the call to sqlite3_unlock_notify(). 5390 ** 5391 ** If the blocked connection is attempting to obtain a write-lock on a 5392 ** shared-cache table, and more than one other connection currently holds 5393 ** a read-lock on the same table, then SQLite arbitrarily selects one of 5394 ** the other connections to use as the blocking connection. 5395 ** 5396 ** There may be at most one unlock-notify callback registered by a 5397 ** blocked connection. If sqlite3_unlock_notify() is called when the 5398 ** blocked connection already has a registered unlock-notify callback, 5399 ** then the new callback replaces the old. If sqlite3_unlock_notify() is 5400 ** called with a NULL pointer as its second argument, then any existing 5401 ** unlock-notify callback is cancelled. The blocked connections 5402 ** unlock-notify callback may also be canceled by closing the blocked 5403 ** connection using [sqlite3_close()]. 5404 ** 5405 ** The unlock-notify callback is not reentrant. If an application invokes 5406 ** any sqlite3_xxx API functions from within an unlock-notify callback, a 5407 ** crash or deadlock may be the result. 5408 ** 5409 ** Unless deadlock is detected (see below), sqlite3_unlock_notify() always 5410 ** returns SQLITE_OK. 5411 ** 5412 ** <b>Callback Invocation Details</b> 5413 ** 5414 ** When an unlock-notify callback is registered, the application provides a 5415 ** single void* pointer that is passed to the callback when it is invoked. 5416 ** However, the signature of the callback function allows SQLite to pass 5417 ** it an array of void* context pointers. The first argument passed to 5418 ** an unlock-notify callback is a pointer to an array of void* pointers, 5419 ** and the second is the number of entries in the array. 5420 ** 5421 ** When a blocking connections transaction is concluded, there may be 5422 ** more than one blocked connection that has registered for an unlock-notify 5423 ** callback. If two or more such blocked connections have specified the 5424 ** same callback function, then instead of invoking the callback function 5425 ** multiple times, it is invoked once with the set of void* context pointers 5426 ** specified by the blocked connections bundled together into an array. 5427 ** This gives the application an opportunity to prioritize any actions 5428 ** related to the set of unblocked database connections. 5429 ** 5430 ** <b>Deadlock Detection</b> 5431 ** 5432 ** Assuming that after registering for an unlock-notify callback a 5433 ** database waits for the callback to be issued before taking any further 5434 ** action (a reasonable assumption), then using this API may cause the 5435 ** application to deadlock. For example, if connection X is waiting for 5436 ** connection Y's transaction to be concluded, and similarly connection 5437 ** Y is waiting on connection X's transaction, then neither connection 5438 ** will proceed and the system may remain deadlocked indefinitely. 5439 ** 5440 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 5441 ** detection. If a given call to sqlite3_unlock_notify() would put the 5442 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no 5443 ** unlock-notify callback is registered. The system is said to be in 5444 ** a deadlocked state if connection A has registered for an unlock-notify 5445 ** callback on the conclusion of connection B's transaction, and connection 5446 ** B has itself registered for an unlock-notify callback when connection 5447 ** A's transaction is concluded. Indirect deadlock is also detected, so 5448 ** the system is also considered to be deadlocked if connection B has 5449 ** registered for an unlock-notify callback on the conclusion of connection 5450 ** C's transaction, where connection C is waiting on connection A. Any 5451 ** number of levels of indirection are allowed. 5452 ** 5453 ** <b>The "DROP TABLE" Exception</b> 5454 ** 5455 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 5456 ** always appropriate to call sqlite3_unlock_notify(). There is however, 5457 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 5458 ** SQLite checks if there are any currently executing SELECT statements 5459 ** that belong to the same connection. If there are, SQLITE_LOCKED is 5460 ** returned. In this case there is no "blocking connection", so invoking 5461 ** sqlite3_unlock_notify() results in the unlock-notify callback being 5462 ** invoked immediately. If the application then re-attempts the "DROP TABLE" 5463 ** or "DROP INDEX" query, an infinite loop might be the result. 5464 ** 5465 ** One way around this problem is to check the extended error code returned 5466 ** by an sqlite3_step() call. If there is a blocking connection, then the 5467 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 5468 ** the special "DROP TABLE/INDEX" case, the extended error code is just 5469 ** SQLITE_LOCKED. 5470 */ 5471 int sqlite3_unlock_notify( 5472 sqlite3 *pBlocked, /* Waiting connection */ 5473 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 5474 void *pNotifyArg /* Argument to pass to xNotify */ 5475 ); 5476 5477 /* 5478 ** Undo the hack that converts floating point types to integer for 5479 ** builds on processors without floating point support. 5480 */ 5481 #ifdef SQLITE_OMIT_FLOATING_POINT 5482 # undef double 5483 #endif 5484 5485 #ifdef __cplusplus 5486 } /* End of the 'extern "C"' block */ 5487 #endif 5488 #endif 5489
