1 /* 2 ** 2001 September 15 3 ** 4 ** The author disclaims copyright to this source code. In place of 5 ** a legal notice, here is a blessing: 6 ** 7 ** May you do good and not evil. 8 ** May you find forgiveness for yourself and forgive others. 9 ** May you share freely, never taking more than you give. 10 ** 11 ************************************************************************* 12 ** This header file defines the interface that the SQLite library 13 ** presents to client programs. If a C-function, structure, datatype, 14 ** or constant definition does not appear in this file, then it is 15 ** not a published API of SQLite, is subject to change without 16 ** notice, and should not be referenced by programs that use SQLite. 17 ** 18 ** Some of the definitions that are in this file are marked as 19 ** "experimental". Experimental interfaces are normally new 20 ** features recently added to SQLite. We do not anticipate changes 21 ** to experimental interfaces but reserve the right to make minor changes 22 ** if experience from use "in the wild" suggest such changes are prudent. 23 ** 24 ** The official C-language API documentation for SQLite is derived 25 ** from comments in this file. This file is the authoritative source 26 ** on how SQLite interfaces are suppose to operate. 27 ** 28 ** The name of this file under configuration management is "sqlite.h.in". 29 ** The makefile makes some minor changes to this file (such as inserting 30 ** the version number) and changes its name to "sqlite3.h" as 31 ** part of the build process. 32 */ 33 #ifndef _SQLITE3_H_ 34 #define _SQLITE3_H_ 35 #include <stdarg.h> /* Needed for the definition of va_list */ 36 37 /* 38 ** Make sure we can call this stuff from C++. 39 */ 40 #ifdef __cplusplus 41 extern "C" { 42 #endif 43 44 45 /* 46 ** Add the ability to override 'extern' 47 */ 48 #ifndef SQLITE_EXTERN 49 # define SQLITE_EXTERN extern 50 #endif 51 52 #ifndef SQLITE_API 53 # define SQLITE_API 54 #endif 55 56 57 /* 58 ** These no-op macros are used in front of interfaces to mark those 59 ** interfaces as either deprecated or experimental. New applications 60 ** should not use deprecated interfaces - they are support for backwards 61 ** compatibility only. Application writers should be aware that 62 ** experimental interfaces are subject to change in point releases. 63 ** 64 ** These macros used to resolve to various kinds of compiler magic that 65 ** would generate warning messages when they were used. But that 66 ** compiler magic ended up generating such a flurry of bug reports 67 ** that we have taken it all out and gone back to using simple 68 ** noop macros. 69 */ 70 #define SQLITE_DEPRECATED 71 #define SQLITE_EXPERIMENTAL 72 73 /* 74 ** Ensure these symbols were not defined by some previous header file. 75 */ 76 #ifdef SQLITE_VERSION 77 # undef SQLITE_VERSION 78 #endif 79 #ifdef SQLITE_VERSION_NUMBER 80 # undef SQLITE_VERSION_NUMBER 81 #endif 82 83 /* 84 ** CAPI3REF: Compile-Time Library Version Numbers 85 ** 86 ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 87 ** evaluates to a string literal that is the SQLite version in the 88 ** format "X.Y.Z" where X is the major version number (always 3 for 89 ** SQLite3) and Y is the minor version number and Z is the release number.)^ 90 ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 91 ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 92 ** numbers used in [SQLITE_VERSION].)^ 93 ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 94 ** be larger than the release from which it is derived. Either Y will 95 ** be held constant and Z will be incremented or else Y will be incremented 96 ** and Z will be reset to zero. 97 ** 98 ** Since version 3.6.18, SQLite source code has been stored in the 99 ** <a href="http://www.fossil-scm.org/">Fossil configuration management 100 ** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 101 ** a string which identifies a particular check-in of SQLite 102 ** within its configuration management system. ^The SQLITE_SOURCE_ID 103 ** string contains the date and time of the check-in (UTC) and an SHA1 104 ** hash of the entire source tree. 105 ** 106 ** See also: [sqlite3_libversion()], 107 ** [sqlite3_libversion_number()], [sqlite3_sourceid()], 108 ** [sqlite_version()] and [sqlite_source_id()]. 109 */ 110 #define SQLITE_VERSION "3.7.7.1" 111 #define SQLITE_VERSION_NUMBER 3007007 112 #define SQLITE_SOURCE_ID "2011-06-28 17:39:05 af0d91adf497f5f36ec3813f04235a6e195a605f" 113 114 /* 115 ** CAPI3REF: Run-Time Library Version Numbers 116 ** KEYWORDS: sqlite3_version, sqlite3_sourceid 117 ** 118 ** These interfaces provide the same information as the [SQLITE_VERSION], 119 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 120 ** but are associated with the library instead of the header file. ^(Cautious 121 ** programmers might include assert() statements in their application to 122 ** verify that values returned by these interfaces match the macros in 123 ** the header, and thus insure that the application is 124 ** compiled with matching library and header files. 125 ** 126 ** <blockquote><pre> 127 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 128 ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 129 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 130 ** </pre></blockquote>)^ 131 ** 132 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 133 ** macro. ^The sqlite3_libversion() function returns a pointer to the 134 ** to the sqlite3_version[] string constant. The sqlite3_libversion() 135 ** function is provided for use in DLLs since DLL users usually do not have 136 ** direct access to string constants within the DLL. ^The 137 ** sqlite3_libversion_number() function returns an integer equal to 138 ** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 139 ** a pointer to a string constant whose value is the same as the 140 ** [SQLITE_SOURCE_ID] C preprocessor macro. 141 ** 142 ** See also: [sqlite_version()] and [sqlite_source_id()]. 143 */ 144 SQLITE_API SQLITE_EXTERN const char sqlite3_version[]; 145 SQLITE_API const char *sqlite3_libversion(void); 146 SQLITE_API const char *sqlite3_sourceid(void); 147 SQLITE_API int sqlite3_libversion_number(void); 148 149 /* 150 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics 151 ** 152 ** ^The sqlite3_compileoption_used() function returns 0 or 1 153 ** indicating whether the specified option was defined at 154 ** compile time. ^The SQLITE_ prefix may be omitted from the 155 ** option name passed to sqlite3_compileoption_used(). 156 ** 157 ** ^The sqlite3_compileoption_get() function allows iterating 158 ** over the list of options that were defined at compile time by 159 ** returning the N-th compile time option string. ^If N is out of range, 160 ** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 161 ** prefix is omitted from any strings returned by 162 ** sqlite3_compileoption_get(). 163 ** 164 ** ^Support for the diagnostic functions sqlite3_compileoption_used() 165 ** and sqlite3_compileoption_get() may be omitted by specifying the 166 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 167 ** 168 ** See also: SQL functions [sqlite_compileoption_used()] and 169 ** [sqlite_compileoption_get()] and the [compile_options pragma]. 170 */ 171 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 172 SQLITE_API int sqlite3_compileoption_used(const char *zOptName); 173 SQLITE_API const char *sqlite3_compileoption_get(int N); 174 #endif 175 176 /* 177 ** CAPI3REF: Test To See If The Library Is Threadsafe 178 ** 179 ** ^The sqlite3_threadsafe() function returns zero if and only if 180 ** SQLite was compiled mutexing code omitted due to the 181 ** [SQLITE_THREADSAFE] compile-time option being set to 0. 182 ** 183 ** SQLite can be compiled with or without mutexes. When 184 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 185 ** are enabled and SQLite is threadsafe. When the 186 ** [SQLITE_THREADSAFE] macro is 0, 187 ** the mutexes are omitted. Without the mutexes, it is not safe 188 ** to use SQLite concurrently from more than one thread. 189 ** 190 ** Enabling mutexes incurs a measurable performance penalty. 191 ** So if speed is of utmost importance, it makes sense to disable 192 ** the mutexes. But for maximum safety, mutexes should be enabled. 193 ** ^The default behavior is for mutexes to be enabled. 194 ** 195 ** This interface can be used by an application to make sure that the 196 ** version of SQLite that it is linking against was compiled with 197 ** the desired setting of the [SQLITE_THREADSAFE] macro. 198 ** 199 ** This interface only reports on the compile-time mutex setting 200 ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 201 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 202 ** can be fully or partially disabled using a call to [sqlite3_config()] 203 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 204 ** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the 205 ** sqlite3_threadsafe() function shows only the compile-time setting of 206 ** thread safety, not any run-time changes to that setting made by 207 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 208 ** is unchanged by calls to sqlite3_config().)^ 209 ** 210 ** See the [threading mode] documentation for additional information. 211 */ 212 SQLITE_API int sqlite3_threadsafe(void); 213 214 /* 215 ** CAPI3REF: Database Connection Handle 216 ** KEYWORDS: {database connection} {database connections} 217 ** 218 ** Each open SQLite database is represented by a pointer to an instance of 219 ** the opaque structure named "sqlite3". It is useful to think of an sqlite3 220 ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 221 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 222 ** is its destructor. There are many other interfaces (such as 223 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 224 ** [sqlite3_busy_timeout()] to name but three) that are methods on an 225 ** sqlite3 object. 226 */ 227 typedef struct sqlite3 sqlite3; 228 229 /* 230 ** CAPI3REF: 64-Bit Integer Types 231 ** KEYWORDS: sqlite_int64 sqlite_uint64 232 ** 233 ** Because there is no cross-platform way to specify 64-bit integer types 234 ** SQLite includes typedefs for 64-bit signed and unsigned integers. 235 ** 236 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 237 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards 238 ** compatibility only. 239 ** 240 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values 241 ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 242 ** sqlite3_uint64 and sqlite_uint64 types can store integer values 243 ** between 0 and +18446744073709551615 inclusive. 244 */ 245 #ifdef SQLITE_INT64_TYPE 246 typedef SQLITE_INT64_TYPE sqlite_int64; 247 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 248 #elif defined(_MSC_VER) || defined(__BORLANDC__) 249 typedef __int64 sqlite_int64; 250 typedef unsigned __int64 sqlite_uint64; 251 #else 252 typedef long long int sqlite_int64; 253 typedef unsigned long long int sqlite_uint64; 254 #endif 255 typedef sqlite_int64 sqlite3_int64; 256 typedef sqlite_uint64 sqlite3_uint64; 257 258 /* 259 ** If compiling for a processor that lacks floating point support, 260 ** substitute integer for floating-point. 261 */ 262 #ifdef SQLITE_OMIT_FLOATING_POINT 263 # define double sqlite3_int64 264 #endif 265 266 /* 267 ** CAPI3REF: Closing A Database Connection 268 ** 269 ** ^The sqlite3_close() routine is the destructor for the [sqlite3] object. 270 ** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is 271 ** successfully destroyed and all associated resources are deallocated. 272 ** 273 ** Applications must [sqlite3_finalize | finalize] all [prepared statements] 274 ** and [sqlite3_blob_close | close] all [BLOB handles] associated with 275 ** the [sqlite3] object prior to attempting to close the object. ^If 276 ** sqlite3_close() is called on a [database connection] that still has 277 ** outstanding [prepared statements] or [BLOB handles], then it returns 278 ** SQLITE_BUSY. 279 ** 280 ** ^If [sqlite3_close()] is invoked while a transaction is open, 281 ** the transaction is automatically rolled back. 282 ** 283 ** The C parameter to [sqlite3_close(C)] must be either a NULL 284 ** pointer or an [sqlite3] object pointer obtained 285 ** from [sqlite3_open()], [sqlite3_open16()], or 286 ** [sqlite3_open_v2()], and not previously closed. 287 ** ^Calling sqlite3_close() with a NULL pointer argument is a 288 ** harmless no-op. 289 */ 290 SQLITE_API int sqlite3_close(sqlite3 *); 291 292 /* 293 ** The type for a callback function. 294 ** This is legacy and deprecated. It is included for historical 295 ** compatibility and is not documented. 296 */ 297 typedef int (*sqlite3_callback)(void*,int,char**, char**); 298 299 /* 300 ** CAPI3REF: One-Step Query Execution Interface 301 ** 302 ** The sqlite3_exec() interface is a convenience wrapper around 303 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 304 ** that allows an application to run multiple statements of SQL 305 ** without having to use a lot of C code. 306 ** 307 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 308 ** semicolon-separate SQL statements passed into its 2nd argument, 309 ** in the context of the [database connection] passed in as its 1st 310 ** argument. ^If the callback function of the 3rd argument to 311 ** sqlite3_exec() is not NULL, then it is invoked for each result row 312 ** coming out of the evaluated SQL statements. ^The 4th argument to 313 ** sqlite3_exec() is relayed through to the 1st argument of each 314 ** callback invocation. ^If the callback pointer to sqlite3_exec() 315 ** is NULL, then no callback is ever invoked and result rows are 316 ** ignored. 317 ** 318 ** ^If an error occurs while evaluating the SQL statements passed into 319 ** sqlite3_exec(), then execution of the current statement stops and 320 ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 321 ** is not NULL then any error message is written into memory obtained 322 ** from [sqlite3_malloc()] and passed back through the 5th parameter. 323 ** To avoid memory leaks, the application should invoke [sqlite3_free()] 324 ** on error message strings returned through the 5th parameter of 325 ** of sqlite3_exec() after the error message string is no longer needed. 326 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 327 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 328 ** NULL before returning. 329 ** 330 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 331 ** routine returns SQLITE_ABORT without invoking the callback again and 332 ** without running any subsequent SQL statements. 333 ** 334 ** ^The 2nd argument to the sqlite3_exec() callback function is the 335 ** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 336 ** callback is an array of pointers to strings obtained as if from 337 ** [sqlite3_column_text()], one for each column. ^If an element of a 338 ** result row is NULL then the corresponding string pointer for the 339 ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 340 ** sqlite3_exec() callback is an array of pointers to strings where each 341 ** entry represents the name of corresponding result column as obtained 342 ** from [sqlite3_column_name()]. 343 ** 344 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 345 ** to an empty string, or a pointer that contains only whitespace and/or 346 ** SQL comments, then no SQL statements are evaluated and the database 347 ** is not changed. 348 ** 349 ** Restrictions: 350 ** 351 ** <ul> 352 ** <li> The application must insure that the 1st parameter to sqlite3_exec() 353 ** is a valid and open [database connection]. 354 ** <li> The application must not close [database connection] specified by 355 ** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 356 ** <li> The application must not modify the SQL statement text passed into 357 ** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 358 ** </ul> 359 */ 360 SQLITE_API int sqlite3_exec( 361 sqlite3*, /* An open database */ 362 const char *sql, /* SQL to be evaluated */ 363 int (*callback)(void*,int,char**,char**), /* Callback function */ 364 void *, /* 1st argument to callback */ 365 char **errmsg /* Error msg written here */ 366 ); 367 368 /* 369 ** CAPI3REF: Result Codes 370 ** KEYWORDS: SQLITE_OK {error code} {error codes} 371 ** KEYWORDS: {result code} {result codes} 372 ** 373 ** Many SQLite functions return an integer result code from the set shown 374 ** here in order to indicates success or failure. 375 ** 376 ** New error codes may be added in future versions of SQLite. 377 ** 378 ** See also: [SQLITE_IOERR_READ | extended result codes], 379 ** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes]. 380 */ 381 #define SQLITE_OK 0 /* Successful result */ 382 /* beginning-of-error-codes */ 383 #define SQLITE_ERROR 1 /* SQL error or missing database */ 384 #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 385 #define SQLITE_PERM 3 /* Access permission denied */ 386 #define SQLITE_ABORT 4 /* Callback routine requested an abort */ 387 #define SQLITE_BUSY 5 /* The database file is locked */ 388 #define SQLITE_LOCKED 6 /* A table in the database is locked */ 389 #define SQLITE_NOMEM 7 /* A malloc() failed */ 390 #define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 391 #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 392 #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 393 #define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 394 #define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 395 #define SQLITE_FULL 13 /* Insertion failed because database is full */ 396 #define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 397 #define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 398 #define SQLITE_EMPTY 16 /* Database is empty */ 399 #define SQLITE_SCHEMA 17 /* The database schema changed */ 400 #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 401 #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 402 #define SQLITE_MISMATCH 20 /* Data type mismatch */ 403 #define SQLITE_MISUSE 21 /* Library used incorrectly */ 404 #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 405 #define SQLITE_AUTH 23 /* Authorization denied */ 406 #define SQLITE_FORMAT 24 /* Auxiliary database format error */ 407 #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 408 #define SQLITE_NOTADB 26 /* File opened that is not a database file */ 409 #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 410 #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 411 /* end-of-error-codes */ 412 413 /* 414 ** CAPI3REF: Extended Result Codes 415 ** KEYWORDS: {extended error code} {extended error codes} 416 ** KEYWORDS: {extended result code} {extended result codes} 417 ** 418 ** In its default configuration, SQLite API routines return one of 26 integer 419 ** [SQLITE_OK | result codes]. However, experience has shown that many of 420 ** these result codes are too coarse-grained. They do not provide as 421 ** much information about problems as programmers might like. In an effort to 422 ** address this, newer versions of SQLite (version 3.3.8 and later) include 423 ** support for additional result codes that provide more detailed information 424 ** about errors. The extended result codes are enabled or disabled 425 ** on a per database connection basis using the 426 ** [sqlite3_extended_result_codes()] API. 427 ** 428 ** Some of the available extended result codes are listed here. 429 ** One may expect the number of extended result codes will be expand 430 ** over time. Software that uses extended result codes should expect 431 ** to see new result codes in future releases of SQLite. 432 ** 433 ** The SQLITE_OK result code will never be extended. It will always 434 ** be exactly zero. 435 */ 436 #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 437 #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 438 #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 439 #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 440 #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 441 #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 442 #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 443 #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 444 #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 445 #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 446 #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 447 #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 448 #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 449 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 450 #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 451 #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 452 #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 453 #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 454 #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 455 #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 456 #define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 457 #define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 458 #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 459 #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 460 #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 461 #define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 462 #define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 463 #define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 464 465 /* 466 ** CAPI3REF: Flags For File Open Operations 467 ** 468 ** These bit values are intended for use in the 469 ** 3rd parameter to the [sqlite3_open_v2()] interface and 470 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 471 */ 472 #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 473 #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 474 #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 475 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 476 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 477 #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 478 #define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 479 #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 480 #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 481 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 482 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 483 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 484 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 485 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 486 #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 487 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 488 #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 489 #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 490 #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 491 492 /* Reserved: 0x00F00000 */ 493 494 /* 495 ** CAPI3REF: Device Characteristics 496 ** 497 ** The xDeviceCharacteristics method of the [sqlite3_io_methods] 498 ** object returns an integer which is a vector of the these 499 ** bit values expressing I/O characteristics of the mass storage 500 ** device that holds the file that the [sqlite3_io_methods] 501 ** refers to. 502 ** 503 ** The SQLITE_IOCAP_ATOMIC property means that all writes of 504 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 505 ** mean that writes of blocks that are nnn bytes in size and 506 ** are aligned to an address which is an integer multiple of 507 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 508 ** that when data is appended to a file, the data is appended 509 ** first then the size of the file is extended, never the other 510 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 511 ** information is written to disk in the same order as calls 512 ** to xWrite(). 513 */ 514 #define SQLITE_IOCAP_ATOMIC 0x00000001 515 #define SQLITE_IOCAP_ATOMIC512 0x00000002 516 #define SQLITE_IOCAP_ATOMIC1K 0x00000004 517 #define SQLITE_IOCAP_ATOMIC2K 0x00000008 518 #define SQLITE_IOCAP_ATOMIC4K 0x00000010 519 #define SQLITE_IOCAP_ATOMIC8K 0x00000020 520 #define SQLITE_IOCAP_ATOMIC16K 0x00000040 521 #define SQLITE_IOCAP_ATOMIC32K 0x00000080 522 #define SQLITE_IOCAP_ATOMIC64K 0x00000100 523 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200 524 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400 525 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 526 527 /* 528 ** CAPI3REF: File Locking Levels 529 ** 530 ** SQLite uses one of these integer values as the second 531 ** argument to calls it makes to the xLock() and xUnlock() methods 532 ** of an [sqlite3_io_methods] object. 533 */ 534 #define SQLITE_LOCK_NONE 0 535 #define SQLITE_LOCK_SHARED 1 536 #define SQLITE_LOCK_RESERVED 2 537 #define SQLITE_LOCK_PENDING 3 538 #define SQLITE_LOCK_EXCLUSIVE 4 539 540 /* 541 ** CAPI3REF: Synchronization Type Flags 542 ** 543 ** When SQLite invokes the xSync() method of an 544 ** [sqlite3_io_methods] object it uses a combination of 545 ** these integer values as the second argument. 546 ** 547 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 548 ** sync operation only needs to flush data to mass storage. Inode 549 ** information need not be flushed. If the lower four bits of the flag 550 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 551 ** If the lower four bits equal SQLITE_SYNC_FULL, that means 552 ** to use Mac OS X style fullsync instead of fsync(). 553 ** 554 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 555 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 556 ** settings. The [synchronous pragma] determines when calls to the 557 ** xSync VFS method occur and applies uniformly across all platforms. 558 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 559 ** energetic or rigorous or forceful the sync operations are and 560 ** only make a difference on Mac OSX for the default SQLite code. 561 ** (Third-party VFS implementations might also make the distinction 562 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 563 ** operating systems natively supported by SQLite, only Mac OSX 564 ** cares about the difference.) 565 */ 566 #define SQLITE_SYNC_NORMAL 0x00002 567 #define SQLITE_SYNC_FULL 0x00003 568 #define SQLITE_SYNC_DATAONLY 0x00010 569 570 /* 571 ** CAPI3REF: OS Interface Open File Handle 572 ** 573 ** An [sqlite3_file] object represents an open file in the 574 ** [sqlite3_vfs | OS interface layer]. Individual OS interface 575 ** implementations will 576 ** want to subclass this object by appending additional fields 577 ** for their own use. The pMethods entry is a pointer to an 578 ** [sqlite3_io_methods] object that defines methods for performing 579 ** I/O operations on the open file. 580 */ 581 typedef struct sqlite3_file sqlite3_file; 582 struct sqlite3_file { 583 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 584 }; 585 586 /* 587 ** CAPI3REF: OS Interface File Virtual Methods Object 588 ** 589 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an 590 ** [sqlite3_file] object (or, more commonly, a subclass of the 591 ** [sqlite3_file] object) with a pointer to an instance of this object. 592 ** This object defines the methods used to perform various operations 593 ** against the open file represented by the [sqlite3_file] object. 594 ** 595 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 596 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 597 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 598 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 599 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 600 ** to NULL. 601 ** 602 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 603 ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 604 ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 605 ** flag may be ORed in to indicate that only the data of the file 606 ** and not its inode needs to be synced. 607 ** 608 ** The integer values to xLock() and xUnlock() are one of 609 ** <ul> 610 ** <li> [SQLITE_LOCK_NONE], 611 ** <li> [SQLITE_LOCK_SHARED], 612 ** <li> [SQLITE_LOCK_RESERVED], 613 ** <li> [SQLITE_LOCK_PENDING], or 614 ** <li> [SQLITE_LOCK_EXCLUSIVE]. 615 ** </ul> 616 ** xLock() increases the lock. xUnlock() decreases the lock. 617 ** The xCheckReservedLock() method checks whether any database connection, 618 ** either in this process or in some other process, is holding a RESERVED, 619 ** PENDING, or EXCLUSIVE lock on the file. It returns true 620 ** if such a lock exists and false otherwise. 621 ** 622 ** The xFileControl() method is a generic interface that allows custom 623 ** VFS implementations to directly control an open file using the 624 ** [sqlite3_file_control()] interface. The second "op" argument is an 625 ** integer opcode. The third argument is a generic pointer intended to 626 ** point to a structure that may contain arguments or space in which to 627 ** write return values. Potential uses for xFileControl() might be 628 ** functions to enable blocking locks with timeouts, to change the 629 ** locking strategy (for example to use dot-file locks), to inquire 630 ** about the status of a lock, or to break stale locks. The SQLite 631 ** core reserves all opcodes less than 100 for its own use. 632 ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 633 ** Applications that define a custom xFileControl method should use opcodes 634 ** greater than 100 to avoid conflicts. VFS implementations should 635 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not 636 ** recognize. 637 ** 638 ** The xSectorSize() method returns the sector size of the 639 ** device that underlies the file. The sector size is the 640 ** minimum write that can be performed without disturbing 641 ** other bytes in the file. The xDeviceCharacteristics() 642 ** method returns a bit vector describing behaviors of the 643 ** underlying device: 644 ** 645 ** <ul> 646 ** <li> [SQLITE_IOCAP_ATOMIC] 647 ** <li> [SQLITE_IOCAP_ATOMIC512] 648 ** <li> [SQLITE_IOCAP_ATOMIC1K] 649 ** <li> [SQLITE_IOCAP_ATOMIC2K] 650 ** <li> [SQLITE_IOCAP_ATOMIC4K] 651 ** <li> [SQLITE_IOCAP_ATOMIC8K] 652 ** <li> [SQLITE_IOCAP_ATOMIC16K] 653 ** <li> [SQLITE_IOCAP_ATOMIC32K] 654 ** <li> [SQLITE_IOCAP_ATOMIC64K] 655 ** <li> [SQLITE_IOCAP_SAFE_APPEND] 656 ** <li> [SQLITE_IOCAP_SEQUENTIAL] 657 ** </ul> 658 ** 659 ** The SQLITE_IOCAP_ATOMIC property means that all writes of 660 ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 661 ** mean that writes of blocks that are nnn bytes in size and 662 ** are aligned to an address which is an integer multiple of 663 ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 664 ** that when data is appended to a file, the data is appended 665 ** first then the size of the file is extended, never the other 666 ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 667 ** information is written to disk in the same order as calls 668 ** to xWrite(). 669 ** 670 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 671 ** in the unread portions of the buffer with zeros. A VFS that 672 ** fails to zero-fill short reads might seem to work. However, 673 ** failure to zero-fill short reads will eventually lead to 674 ** database corruption. 675 */ 676 typedef struct sqlite3_io_methods sqlite3_io_methods; 677 struct sqlite3_io_methods { 678 int iVersion; 679 int (*xClose)(sqlite3_file*); 680 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 681 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 682 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 683 int (*xSync)(sqlite3_file*, int flags); 684 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 685 int (*xLock)(sqlite3_file*, int); 686 int (*xUnlock)(sqlite3_file*, int); 687 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 688 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 689 int (*xSectorSize)(sqlite3_file*); 690 int (*xDeviceCharacteristics)(sqlite3_file*); 691 /* Methods above are valid for version 1 */ 692 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 693 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 694 void (*xShmBarrier)(sqlite3_file*); 695 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 696 /* Methods above are valid for version 2 */ 697 /* Additional methods may be added in future releases */ 698 }; 699 700 /* 701 ** CAPI3REF: Standard File Control Opcodes 702 ** 703 ** These integer constants are opcodes for the xFileControl method 704 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 705 ** interface. 706 ** 707 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 708 ** opcode causes the xFileControl method to write the current state of 709 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 710 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 711 ** into an integer that the pArg argument points to. This capability 712 ** is used during testing and only needs to be supported when SQLITE_TEST 713 ** is defined. 714 ** 715 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 716 ** layer a hint of how large the database file will grow to be during the 717 ** current transaction. This hint is not guaranteed to be accurate but it 718 ** is often close. The underlying VFS might choose to preallocate database 719 ** file space based on this hint in order to help writes to the database 720 ** file run faster. 721 ** 722 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 723 ** extends and truncates the database file in chunks of a size specified 724 ** by the user. The fourth argument to [sqlite3_file_control()] should 725 ** point to an integer (type int) containing the new chunk-size to use 726 ** for the nominated database. Allocating database file space in large 727 ** chunks (say 1MB at a time), may reduce file-system fragmentation and 728 ** improve performance on some systems. 729 ** 730 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 731 ** to the [sqlite3_file] object associated with a particular database 732 ** connection. See the [sqlite3_file_control()] documentation for 733 ** additional information. 734 ** 735 ** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by 736 ** SQLite and sent to all VFSes in place of a call to the xSync method 737 ** when the database connection has [PRAGMA synchronous] set to OFF.)^ 738 ** Some specialized VFSes need this signal in order to operate correctly 739 ** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most 740 ** VFSes do not need this signal and should silently ignore this opcode. 741 ** Applications should not call [sqlite3_file_control()] with this 742 ** opcode as doing so may disrupt the operation of the specialized VFSes 743 ** that do require it. 744 */ 745 #define SQLITE_FCNTL_LOCKSTATE 1 746 #define SQLITE_GET_LOCKPROXYFILE 2 747 #define SQLITE_SET_LOCKPROXYFILE 3 748 #define SQLITE_LAST_ERRNO 4 749 #define SQLITE_FCNTL_SIZE_HINT 5 750 #define SQLITE_FCNTL_CHUNK_SIZE 6 751 #define SQLITE_FCNTL_FILE_POINTER 7 752 #define SQLITE_FCNTL_SYNC_OMITTED 8 753 754 755 /* 756 ** CAPI3REF: Mutex Handle 757 ** 758 ** The mutex module within SQLite defines [sqlite3_mutex] to be an 759 ** abstract type for a mutex object. The SQLite core never looks 760 ** at the internal representation of an [sqlite3_mutex]. It only 761 ** deals with pointers to the [sqlite3_mutex] object. 762 ** 763 ** Mutexes are created using [sqlite3_mutex_alloc()]. 764 */ 765 typedef struct sqlite3_mutex sqlite3_mutex; 766 767 /* 768 ** CAPI3REF: OS Interface Object 769 ** 770 ** An instance of the sqlite3_vfs object defines the interface between 771 ** the SQLite core and the underlying operating system. The "vfs" 772 ** in the name of the object stands for "virtual file system". See 773 ** the [VFS | VFS documentation] for further information. 774 ** 775 ** The value of the iVersion field is initially 1 but may be larger in 776 ** future versions of SQLite. Additional fields may be appended to this 777 ** object when the iVersion value is increased. Note that the structure 778 ** of the sqlite3_vfs object changes in the transaction between 779 ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 780 ** modified. 781 ** 782 ** The szOsFile field is the size of the subclassed [sqlite3_file] 783 ** structure used by this VFS. mxPathname is the maximum length of 784 ** a pathname in this VFS. 785 ** 786 ** Registered sqlite3_vfs objects are kept on a linked list formed by 787 ** the pNext pointer. The [sqlite3_vfs_register()] 788 ** and [sqlite3_vfs_unregister()] interfaces manage this list 789 ** in a thread-safe way. The [sqlite3_vfs_find()] interface 790 ** searches the list. Neither the application code nor the VFS 791 ** implementation should use the pNext pointer. 792 ** 793 ** The pNext field is the only field in the sqlite3_vfs 794 ** structure that SQLite will ever modify. SQLite will only access 795 ** or modify this field while holding a particular static mutex. 796 ** The application should never modify anything within the sqlite3_vfs 797 ** object once the object has been registered. 798 ** 799 ** The zName field holds the name of the VFS module. The name must 800 ** be unique across all VFS modules. 801 ** 802 ** [[sqlite3_vfs.xOpen]] 803 ** ^SQLite guarantees that the zFilename parameter to xOpen 804 ** is either a NULL pointer or string obtained 805 ** from xFullPathname() with an optional suffix added. 806 ** ^If a suffix is added to the zFilename parameter, it will 807 ** consist of a single "-" character followed by no more than 808 ** 10 alphanumeric and/or "-" characters. 809 ** ^SQLite further guarantees that 810 ** the string will be valid and unchanged until xClose() is 811 ** called. Because of the previous sentence, 812 ** the [sqlite3_file] can safely store a pointer to the 813 ** filename if it needs to remember the filename for some reason. 814 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen 815 ** must invent its own temporary name for the file. ^Whenever the 816 ** xFilename parameter is NULL it will also be the case that the 817 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 818 ** 819 ** The flags argument to xOpen() includes all bits set in 820 ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 821 ** or [sqlite3_open16()] is used, then flags includes at least 822 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 823 ** If xOpen() opens a file read-only then it sets *pOutFlags to 824 ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 825 ** 826 ** ^(SQLite will also add one of the following flags to the xOpen() 827 ** call, depending on the object being opened: 828 ** 829 ** <ul> 830 ** <li> [SQLITE_OPEN_MAIN_DB] 831 ** <li> [SQLITE_OPEN_MAIN_JOURNAL] 832 ** <li> [SQLITE_OPEN_TEMP_DB] 833 ** <li> [SQLITE_OPEN_TEMP_JOURNAL] 834 ** <li> [SQLITE_OPEN_TRANSIENT_DB] 835 ** <li> [SQLITE_OPEN_SUBJOURNAL] 836 ** <li> [SQLITE_OPEN_MASTER_JOURNAL] 837 ** <li> [SQLITE_OPEN_WAL] 838 ** </ul>)^ 839 ** 840 ** The file I/O implementation can use the object type flags to 841 ** change the way it deals with files. For example, an application 842 ** that does not care about crash recovery or rollback might make 843 ** the open of a journal file a no-op. Writes to this journal would 844 ** also be no-ops, and any attempt to read the journal would return 845 ** SQLITE_IOERR. Or the implementation might recognize that a database 846 ** file will be doing page-aligned sector reads and writes in a random 847 ** order and set up its I/O subsystem accordingly. 848 ** 849 ** SQLite might also add one of the following flags to the xOpen method: 850 ** 851 ** <ul> 852 ** <li> [SQLITE_OPEN_DELETEONCLOSE] 853 ** <li> [SQLITE_OPEN_EXCLUSIVE] 854 ** </ul> 855 ** 856 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 857 ** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 858 ** will be set for TEMP databases and their journals, transient 859 ** databases, and subjournals. 860 ** 861 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 862 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly 863 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 864 ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 865 ** SQLITE_OPEN_CREATE, is used to indicate that file should always 866 ** be created, and that it is an error if it already exists. 867 ** It is <i>not</i> used to indicate the file should be opened 868 ** for exclusive access. 869 ** 870 ** ^At least szOsFile bytes of memory are allocated by SQLite 871 ** to hold the [sqlite3_file] structure passed as the third 872 ** argument to xOpen. The xOpen method does not have to 873 ** allocate the structure; it should just fill it in. Note that 874 ** the xOpen method must set the sqlite3_file.pMethods to either 875 ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 876 ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 877 ** element will be valid after xOpen returns regardless of the success 878 ** or failure of the xOpen call. 879 ** 880 ** [[sqlite3_vfs.xAccess]] 881 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 882 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 883 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 884 ** to test whether a file is at least readable. The file can be a 885 ** directory. 886 ** 887 ** ^SQLite will always allocate at least mxPathname+1 bytes for the 888 ** output buffer xFullPathname. The exact size of the output buffer 889 ** is also passed as a parameter to both methods. If the output buffer 890 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 891 ** handled as a fatal error by SQLite, vfs implementations should endeavor 892 ** to prevent this by setting mxPathname to a sufficiently large value. 893 ** 894 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 895 ** interfaces are not strictly a part of the filesystem, but they are 896 ** included in the VFS structure for completeness. 897 ** The xRandomness() function attempts to return nBytes bytes 898 ** of good-quality randomness into zOut. The return value is 899 ** the actual number of bytes of randomness obtained. 900 ** The xSleep() method causes the calling thread to sleep for at 901 ** least the number of microseconds given. ^The xCurrentTime() 902 ** method returns a Julian Day Number for the current date and time as 903 ** a floating point value. 904 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 905 ** Day Number multiplied by 86400000 (the number of milliseconds in 906 ** a 24-hour day). 907 ** ^SQLite will use the xCurrentTimeInt64() method to get the current 908 ** date and time if that method is available (if iVersion is 2 or 909 ** greater and the function pointer is not NULL) and will fall back 910 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 911 ** 912 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 913 ** are not used by the SQLite core. These optional interfaces are provided 914 ** by some VFSes to facilitate testing of the VFS code. By overriding 915 ** system calls with functions under its control, a test program can 916 ** simulate faults and error conditions that would otherwise be difficult 917 ** or impossible to induce. The set of system calls that can be overridden 918 ** varies from one VFS to another, and from one version of the same VFS to the 919 ** next. Applications that use these interfaces must be prepared for any 920 ** or all of these interfaces to be NULL or for their behavior to change 921 ** from one release to the next. Applications must not attempt to access 922 ** any of these methods if the iVersion of the VFS is less than 3. 923 */ 924 typedef struct sqlite3_vfs sqlite3_vfs; 925 typedef void (*sqlite3_syscall_ptr)(void); 926 struct sqlite3_vfs { 927 int iVersion; /* Structure version number (currently 3) */ 928 int szOsFile; /* Size of subclassed sqlite3_file */ 929 int mxPathname; /* Maximum file pathname length */ 930 sqlite3_vfs *pNext; /* Next registered VFS */ 931 const char *zName; /* Name of this virtual file system */ 932 void *pAppData; /* Pointer to application-specific data */ 933 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 934 int flags, int *pOutFlags); 935 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 936 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 937 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 938 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 939 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 940 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 941 void (*xDlClose)(sqlite3_vfs*, void*); 942 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 943 int (*xSleep)(sqlite3_vfs*, int microseconds); 944 int (*xCurrentTime)(sqlite3_vfs*, double*); 945 int (*xGetLastError)(sqlite3_vfs*, int, char *); 946 /* 947 ** The methods above are in version 1 of the sqlite_vfs object 948 ** definition. Those that follow are added in version 2 or later 949 */ 950 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 951 /* 952 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 953 ** Those below are for version 3 and greater. 954 */ 955 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 956 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 957 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 958 /* 959 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 960 ** New fields may be appended in figure versions. The iVersion 961 ** value will increment whenever this happens. 962 */ 963 }; 964 965 /* 966 ** CAPI3REF: Flags for the xAccess VFS method 967 ** 968 ** These integer constants can be used as the third parameter to 969 ** the xAccess method of an [sqlite3_vfs] object. They determine 970 ** what kind of permissions the xAccess method is looking for. 971 ** With SQLITE_ACCESS_EXISTS, the xAccess method 972 ** simply checks whether the file exists. 973 ** With SQLITE_ACCESS_READWRITE, the xAccess method 974 ** checks whether the named directory is both readable and writable 975 ** (in other words, if files can be added, removed, and renamed within 976 ** the directory). 977 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the 978 ** [temp_store_directory pragma], though this could change in a future 979 ** release of SQLite. 980 ** With SQLITE_ACCESS_READ, the xAccess method 981 ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 982 ** currently unused, though it might be used in a future release of 983 ** SQLite. 984 */ 985 #define SQLITE_ACCESS_EXISTS 0 986 #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 987 #define SQLITE_ACCESS_READ 2 /* Unused */ 988 989 /* 990 ** CAPI3REF: Flags for the xShmLock VFS method 991 ** 992 ** These integer constants define the various locking operations 993 ** allowed by the xShmLock method of [sqlite3_io_methods]. The 994 ** following are the only legal combinations of flags to the 995 ** xShmLock method: 996 ** 997 ** <ul> 998 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 999 ** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1000 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1001 ** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1002 ** </ul> 1003 ** 1004 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1005 ** was given no the corresponding lock. 1006 ** 1007 ** The xShmLock method can transition between unlocked and SHARED or 1008 ** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1009 ** and EXCLUSIVE. 1010 */ 1011 #define SQLITE_SHM_UNLOCK 1 1012 #define SQLITE_SHM_LOCK 2 1013 #define SQLITE_SHM_SHARED 4 1014 #define SQLITE_SHM_EXCLUSIVE 8 1015 1016 /* 1017 ** CAPI3REF: Maximum xShmLock index 1018 ** 1019 ** The xShmLock method on [sqlite3_io_methods] may use values 1020 ** between 0 and this upper bound as its "offset" argument. 1021 ** The SQLite core will never attempt to acquire or release a 1022 ** lock outside of this range 1023 */ 1024 #define SQLITE_SHM_NLOCK 8 1025 1026 1027 /* 1028 ** CAPI3REF: Initialize The SQLite Library 1029 ** 1030 ** ^The sqlite3_initialize() routine initializes the 1031 ** SQLite library. ^The sqlite3_shutdown() routine 1032 ** deallocates any resources that were allocated by sqlite3_initialize(). 1033 ** These routines are designed to aid in process initialization and 1034 ** shutdown on embedded systems. Workstation applications using 1035 ** SQLite normally do not need to invoke either of these routines. 1036 ** 1037 ** A call to sqlite3_initialize() is an "effective" call if it is 1038 ** the first time sqlite3_initialize() is invoked during the lifetime of 1039 ** the process, or if it is the first time sqlite3_initialize() is invoked 1040 ** following a call to sqlite3_shutdown(). ^(Only an effective call 1041 ** of sqlite3_initialize() does any initialization. All other calls 1042 ** are harmless no-ops.)^ 1043 ** 1044 ** A call to sqlite3_shutdown() is an "effective" call if it is the first 1045 ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1046 ** an effective call to sqlite3_shutdown() does any deinitialization. 1047 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1048 ** 1049 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1050 ** is not. The sqlite3_shutdown() interface must only be called from a 1051 ** single thread. All open [database connections] must be closed and all 1052 ** other SQLite resources must be deallocated prior to invoking 1053 ** sqlite3_shutdown(). 1054 ** 1055 ** Among other things, ^sqlite3_initialize() will invoke 1056 ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1057 ** will invoke sqlite3_os_end(). 1058 ** 1059 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1060 ** ^If for some reason, sqlite3_initialize() is unable to initialize 1061 ** the library (perhaps it is unable to allocate a needed resource such 1062 ** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1063 ** 1064 ** ^The sqlite3_initialize() routine is called internally by many other 1065 ** SQLite interfaces so that an application usually does not need to 1066 ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1067 ** calls sqlite3_initialize() so the SQLite library will be automatically 1068 ** initialized when [sqlite3_open()] is called if it has not be initialized 1069 ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1070 ** compile-time option, then the automatic calls to sqlite3_initialize() 1071 ** are omitted and the application must call sqlite3_initialize() directly 1072 ** prior to using any other SQLite interface. For maximum portability, 1073 ** it is recommended that applications always invoke sqlite3_initialize() 1074 ** directly prior to using any other SQLite interface. Future releases 1075 ** of SQLite may require this. In other words, the behavior exhibited 1076 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1077 ** default behavior in some future release of SQLite. 1078 ** 1079 ** The sqlite3_os_init() routine does operating-system specific 1080 ** initialization of the SQLite library. The sqlite3_os_end() 1081 ** routine undoes the effect of sqlite3_os_init(). Typical tasks 1082 ** performed by these routines include allocation or deallocation 1083 ** of static resources, initialization of global variables, 1084 ** setting up a default [sqlite3_vfs] module, or setting up 1085 ** a default configuration using [sqlite3_config()]. 1086 ** 1087 ** The application should never invoke either sqlite3_os_init() 1088 ** or sqlite3_os_end() directly. The application should only invoke 1089 ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1090 ** interface is called automatically by sqlite3_initialize() and 1091 ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1092 ** implementations for sqlite3_os_init() and sqlite3_os_end() 1093 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1094 ** When [custom builds | built for other platforms] 1095 ** (using the [SQLITE_OS_OTHER=1] compile-time 1096 ** option) the application must supply a suitable implementation for 1097 ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1098 ** implementation of sqlite3_os_init() or sqlite3_os_end() 1099 ** must return [SQLITE_OK] on success and some other [error code] upon 1100 ** failure. 1101 */ 1102 SQLITE_API int sqlite3_initialize(void); 1103 SQLITE_API int sqlite3_shutdown(void); 1104 SQLITE_API int sqlite3_os_init(void); 1105 SQLITE_API int sqlite3_os_end(void); 1106 1107 /* 1108 ** CAPI3REF: Configuring The SQLite Library 1109 ** 1110 ** The sqlite3_config() interface is used to make global configuration 1111 ** changes to SQLite in order to tune SQLite to the specific needs of 1112 ** the application. The default configuration is recommended for most 1113 ** applications and so this routine is usually not necessary. It is 1114 ** provided to support rare applications with unusual needs. 1115 ** 1116 ** The sqlite3_config() interface is not threadsafe. The application 1117 ** must insure that no other SQLite interfaces are invoked by other 1118 ** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1119 ** may only be invoked prior to library initialization using 1120 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1121 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1122 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1123 ** Note, however, that ^sqlite3_config() can be called as part of the 1124 ** implementation of an application-defined [sqlite3_os_init()]. 1125 ** 1126 ** The first argument to sqlite3_config() is an integer 1127 ** [configuration option] that determines 1128 ** what property of SQLite is to be configured. Subsequent arguments 1129 ** vary depending on the [configuration option] 1130 ** in the first argument. 1131 ** 1132 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1133 ** ^If the option is unknown or SQLite is unable to set the option 1134 ** then this routine returns a non-zero [error code]. 1135 */ 1136 SQLITE_API int sqlite3_config(int, ...); 1137 1138 /* 1139 ** CAPI3REF: Configure database connections 1140 ** 1141 ** The sqlite3_db_config() interface is used to make configuration 1142 ** changes to a [database connection]. The interface is similar to 1143 ** [sqlite3_config()] except that the changes apply to a single 1144 ** [database connection] (specified in the first argument). 1145 ** 1146 ** The second argument to sqlite3_db_config(D,V,...) is the 1147 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1148 ** that indicates what aspect of the [database connection] is being configured. 1149 ** Subsequent arguments vary depending on the configuration verb. 1150 ** 1151 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1152 ** the call is considered successful. 1153 */ 1154 SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...); 1155 1156 /* 1157 ** CAPI3REF: Memory Allocation Routines 1158 ** 1159 ** An instance of this object defines the interface between SQLite 1160 ** and low-level memory allocation routines. 1161 ** 1162 ** This object is used in only one place in the SQLite interface. 1163 ** A pointer to an instance of this object is the argument to 1164 ** [sqlite3_config()] when the configuration option is 1165 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1166 ** By creating an instance of this object 1167 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1168 ** during configuration, an application can specify an alternative 1169 ** memory allocation subsystem for SQLite to use for all of its 1170 ** dynamic memory needs. 1171 ** 1172 ** Note that SQLite comes with several [built-in memory allocators] 1173 ** that are perfectly adequate for the overwhelming majority of applications 1174 ** and that this object is only useful to a tiny minority of applications 1175 ** with specialized memory allocation requirements. This object is 1176 ** also used during testing of SQLite in order to specify an alternative 1177 ** memory allocator that simulates memory out-of-memory conditions in 1178 ** order to verify that SQLite recovers gracefully from such 1179 ** conditions. 1180 ** 1181 ** The xMalloc and xFree methods must work like the 1182 ** malloc() and free() functions from the standard C library. 1183 ** The xRealloc method must work like realloc() from the standard C library 1184 ** with the exception that if the second argument to xRealloc is zero, 1185 ** xRealloc must be a no-op - it must not perform any allocation or 1186 ** deallocation. ^SQLite guarantees that the second argument to 1187 ** xRealloc is always a value returned by a prior call to xRoundup. 1188 ** And so in cases where xRoundup always returns a positive number, 1189 ** xRealloc can perform exactly as the standard library realloc() and 1190 ** still be in compliance with this specification. 1191 ** 1192 ** xSize should return the allocated size of a memory allocation 1193 ** previously obtained from xMalloc or xRealloc. The allocated size 1194 ** is always at least as big as the requested size but may be larger. 1195 ** 1196 ** The xRoundup method returns what would be the allocated size of 1197 ** a memory allocation given a particular requested size. Most memory 1198 ** allocators round up memory allocations at least to the next multiple 1199 ** of 8. Some allocators round up to a larger multiple or to a power of 2. 1200 ** Every memory allocation request coming in through [sqlite3_malloc()] 1201 ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1202 ** that causes the corresponding memory allocation to fail. 1203 ** 1204 ** The xInit method initializes the memory allocator. (For example, 1205 ** it might allocate any require mutexes or initialize internal data 1206 ** structures. The xShutdown method is invoked (indirectly) by 1207 ** [sqlite3_shutdown()] and should deallocate any resources acquired 1208 ** by xInit. The pAppData pointer is used as the only parameter to 1209 ** xInit and xShutdown. 1210 ** 1211 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1212 ** the xInit method, so the xInit method need not be threadsafe. The 1213 ** xShutdown method is only called from [sqlite3_shutdown()] so it does 1214 ** not need to be threadsafe either. For all other methods, SQLite 1215 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1216 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1217 ** it is by default) and so the methods are automatically serialized. 1218 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1219 ** methods must be threadsafe or else make their own arrangements for 1220 ** serialization. 1221 ** 1222 ** SQLite will never invoke xInit() more than once without an intervening 1223 ** call to xShutdown(). 1224 */ 1225 typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1226 struct sqlite3_mem_methods { 1227 void *(*xMalloc)(int); /* Memory allocation function */ 1228 void (*xFree)(void*); /* Free a prior allocation */ 1229 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1230 int (*xSize)(void*); /* Return the size of an allocation */ 1231 int (*xRoundup)(int); /* Round up request size to allocation size */ 1232 int (*xInit)(void*); /* Initialize the memory allocator */ 1233 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1234 void *pAppData; /* Argument to xInit() and xShutdown() */ 1235 }; 1236 1237 /* 1238 ** CAPI3REF: Configuration Options 1239 ** KEYWORDS: {configuration option} 1240 ** 1241 ** These constants are the available integer configuration options that 1242 ** can be passed as the first argument to the [sqlite3_config()] interface. 1243 ** 1244 ** New configuration options may be added in future releases of SQLite. 1245 ** Existing configuration options might be discontinued. Applications 1246 ** should check the return code from [sqlite3_config()] to make sure that 1247 ** the call worked. The [sqlite3_config()] interface will return a 1248 ** non-zero [error code] if a discontinued or unsupported configuration option 1249 ** is invoked. 1250 ** 1251 ** <dl> 1252 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1253 ** <dd>There are no arguments to this option. ^This option sets the 1254 ** [threading mode] to Single-thread. In other words, it disables 1255 ** all mutexing and puts SQLite into a mode where it can only be used 1256 ** by a single thread. ^If SQLite is compiled with 1257 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1258 ** it is not possible to change the [threading mode] from its default 1259 ** value of Single-thread and so [sqlite3_config()] will return 1260 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1261 ** configuration option.</dd> 1262 ** 1263 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1264 ** <dd>There are no arguments to this option. ^This option sets the 1265 ** [threading mode] to Multi-thread. In other words, it disables 1266 ** mutexing on [database connection] and [prepared statement] objects. 1267 ** The application is responsible for serializing access to 1268 ** [database connections] and [prepared statements]. But other mutexes 1269 ** are enabled so that SQLite will be safe to use in a multi-threaded 1270 ** environment as long as no two threads attempt to use the same 1271 ** [database connection] at the same time. ^If SQLite is compiled with 1272 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1273 ** it is not possible to set the Multi-thread [threading mode] and 1274 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1275 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1276 ** 1277 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1278 ** <dd>There are no arguments to this option. ^This option sets the 1279 ** [threading mode] to Serialized. In other words, this option enables 1280 ** all mutexes including the recursive 1281 ** mutexes on [database connection] and [prepared statement] objects. 1282 ** In this mode (which is the default when SQLite is compiled with 1283 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1284 ** to [database connections] and [prepared statements] so that the 1285 ** application is free to use the same [database connection] or the 1286 ** same [prepared statement] in different threads at the same time. 1287 ** ^If SQLite is compiled with 1288 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1289 ** it is not possible to set the Serialized [threading mode] and 1290 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1291 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1292 ** 1293 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1294 ** <dd> ^(This option takes a single argument which is a pointer to an 1295 ** instance of the [sqlite3_mem_methods] structure. The argument specifies 1296 ** alternative low-level memory allocation routines to be used in place of 1297 ** the memory allocation routines built into SQLite.)^ ^SQLite makes 1298 ** its own private copy of the content of the [sqlite3_mem_methods] structure 1299 ** before the [sqlite3_config()] call returns.</dd> 1300 ** 1301 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1302 ** <dd> ^(This option takes a single argument which is a pointer to an 1303 ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1304 ** structure is filled with the currently defined memory allocation routines.)^ 1305 ** This option can be used to overload the default memory allocation 1306 ** routines with a wrapper that simulations memory allocation failure or 1307 ** tracks memory usage, for example. </dd> 1308 ** 1309 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1310 ** <dd> ^This option takes single argument of type int, interpreted as a 1311 ** boolean, which enables or disables the collection of memory allocation 1312 ** statistics. ^(When memory allocation statistics are disabled, the 1313 ** following SQLite interfaces become non-operational: 1314 ** <ul> 1315 ** <li> [sqlite3_memory_used()] 1316 ** <li> [sqlite3_memory_highwater()] 1317 ** <li> [sqlite3_soft_heap_limit64()] 1318 ** <li> [sqlite3_status()] 1319 ** </ul>)^ 1320 ** ^Memory allocation statistics are enabled by default unless SQLite is 1321 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1322 ** allocation statistics are disabled by default. 1323 ** </dd> 1324 ** 1325 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1326 ** <dd> ^This option specifies a static memory buffer that SQLite can use for 1327 ** scratch memory. There are three arguments: A pointer an 8-byte 1328 ** aligned memory buffer from which the scratch allocations will be 1329 ** drawn, the size of each scratch allocation (sz), 1330 ** and the maximum number of scratch allocations (N). The sz 1331 ** argument must be a multiple of 16. 1332 ** The first argument must be a pointer to an 8-byte aligned buffer 1333 ** of at least sz*N bytes of memory. 1334 ** ^SQLite will use no more than two scratch buffers per thread. So 1335 ** N should be set to twice the expected maximum number of threads. 1336 ** ^SQLite will never require a scratch buffer that is more than 6 1337 ** times the database page size. ^If SQLite needs needs additional 1338 ** scratch memory beyond what is provided by this configuration option, then 1339 ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1340 ** 1341 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1342 ** <dd> ^This option specifies a static memory buffer that SQLite can use for 1343 ** the database page cache with the default page cache implementation. 1344 ** This configuration should not be used if an application-define page 1345 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option. 1346 ** There are three arguments to this option: A pointer to 8-byte aligned 1347 ** memory, the size of each page buffer (sz), and the number of pages (N). 1348 ** The sz argument should be the size of the largest database page 1349 ** (a power of two between 512 and 32768) plus a little extra for each 1350 ** page header. ^The page header size is 20 to 40 bytes depending on 1351 ** the host architecture. ^It is harmless, apart from the wasted memory, 1352 ** to make sz a little too large. The first 1353 ** argument should point to an allocation of at least sz*N bytes of memory. 1354 ** ^SQLite will use the memory provided by the first argument to satisfy its 1355 ** memory needs for the first N pages that it adds to cache. ^If additional 1356 ** page cache memory is needed beyond what is provided by this option, then 1357 ** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1358 ** The pointer in the first argument must 1359 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1360 ** will be undefined.</dd> 1361 ** 1362 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1363 ** <dd> ^This option specifies a static memory buffer that SQLite will use 1364 ** for all of its dynamic memory allocation needs beyond those provided 1365 ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1366 ** There are three arguments: An 8-byte aligned pointer to the memory, 1367 ** the number of bytes in the memory buffer, and the minimum allocation size. 1368 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1369 ** to using its default memory allocator (the system malloc() implementation), 1370 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1371 ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1372 ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1373 ** allocator is engaged to handle all of SQLites memory allocation needs. 1374 ** The first pointer (the memory pointer) must be aligned to an 8-byte 1375 ** boundary or subsequent behavior of SQLite will be undefined. 1376 ** The minimum allocation size is capped at 2^12. Reasonable values 1377 ** for the minimum allocation size are 2^5 through 2^8.</dd> 1378 ** 1379 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1380 ** <dd> ^(This option takes a single argument which is a pointer to an 1381 ** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1382 ** alternative low-level mutex routines to be used in place 1383 ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1384 ** content of the [sqlite3_mutex_methods] structure before the call to 1385 ** [sqlite3_config()] returns. ^If SQLite is compiled with 1386 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1387 ** the entire mutexing subsystem is omitted from the build and hence calls to 1388 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1389 ** return [SQLITE_ERROR].</dd> 1390 ** 1391 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1392 ** <dd> ^(This option takes a single argument which is a pointer to an 1393 ** instance of the [sqlite3_mutex_methods] structure. The 1394 ** [sqlite3_mutex_methods] 1395 ** structure is filled with the currently defined mutex routines.)^ 1396 ** This option can be used to overload the default mutex allocation 1397 ** routines with a wrapper used to track mutex usage for performance 1398 ** profiling or testing, for example. ^If SQLite is compiled with 1399 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1400 ** the entire mutexing subsystem is omitted from the build and hence calls to 1401 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1402 ** return [SQLITE_ERROR].</dd> 1403 ** 1404 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1405 ** <dd> ^(This option takes two arguments that determine the default 1406 ** memory allocation for the lookaside memory allocator on each 1407 ** [database connection]. The first argument is the 1408 ** size of each lookaside buffer slot and the second is the number of 1409 ** slots allocated to each database connection.)^ ^(This option sets the 1410 ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1411 ** verb to [sqlite3_db_config()] can be used to change the lookaside 1412 ** configuration on individual connections.)^ </dd> 1413 ** 1414 ** [[SQLITE_CONFIG_PCACHE]] <dt>SQLITE_CONFIG_PCACHE</dt> 1415 ** <dd> ^(This option takes a single argument which is a pointer to 1416 ** an [sqlite3_pcache_methods] object. This object specifies the interface 1417 ** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1418 ** object and uses it for page cache memory allocations.</dd> 1419 ** 1420 ** [[SQLITE_CONFIG_GETPCACHE]] <dt>SQLITE_CONFIG_GETPCACHE</dt> 1421 ** <dd> ^(This option takes a single argument which is a pointer to an 1422 ** [sqlite3_pcache_methods] object. SQLite copies of the current 1423 ** page cache implementation into that object.)^ </dd> 1424 ** 1425 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1426 ** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1427 ** function with a call signature of void(*)(void*,int,const char*), 1428 ** and a pointer to void. ^If the function pointer is not NULL, it is 1429 ** invoked by [sqlite3_log()] to process each logging event. ^If the 1430 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1431 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1432 ** passed through as the first parameter to the application-defined logger 1433 ** function whenever that function is invoked. ^The second parameter to 1434 ** the logger function is a copy of the first parameter to the corresponding 1435 ** [sqlite3_log()] call and is intended to be a [result code] or an 1436 ** [extended result code]. ^The third parameter passed to the logger is 1437 ** log message after formatting via [sqlite3_snprintf()]. 1438 ** The SQLite logging interface is not reentrant; the logger function 1439 ** supplied by the application must not invoke any SQLite interface. 1440 ** In a multi-threaded application, the application-defined logger 1441 ** function must be threadsafe. </dd> 1442 ** 1443 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1444 ** <dd> This option takes a single argument of type int. If non-zero, then 1445 ** URI handling is globally enabled. If the parameter is zero, then URI handling 1446 ** is globally disabled. If URI handling is globally enabled, all filenames 1447 ** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or 1448 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1449 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1450 ** connection is opened. If it is globally disabled, filenames are 1451 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1452 ** database connection is opened. By default, URI handling is globally 1453 ** disabled. The default value may be changed by compiling with the 1454 ** [SQLITE_USE_URI] symbol defined. 1455 ** </dl> 1456 */ 1457 #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1458 #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1459 #define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1460 #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1461 #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1462 #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1463 #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1464 #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1465 #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1466 #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1467 #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1468 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1469 #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1470 #define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */ 1471 #define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */ 1472 #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1473 #define SQLITE_CONFIG_URI 17 /* int */ 1474 1475 /* 1476 ** CAPI3REF: Database Connection Configuration Options 1477 ** 1478 ** These constants are the available integer configuration options that 1479 ** can be passed as the second argument to the [sqlite3_db_config()] interface. 1480 ** 1481 ** New configuration options may be added in future releases of SQLite. 1482 ** Existing configuration options might be discontinued. Applications 1483 ** should check the return code from [sqlite3_db_config()] to make sure that 1484 ** the call worked. ^The [sqlite3_db_config()] interface will return a 1485 ** non-zero [error code] if a discontinued or unsupported configuration option 1486 ** is invoked. 1487 ** 1488 ** <dl> 1489 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1490 ** <dd> ^This option takes three additional arguments that determine the 1491 ** [lookaside memory allocator] configuration for the [database connection]. 1492 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1493 ** pointer to a memory buffer to use for lookaside memory. 1494 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1495 ** may be NULL in which case SQLite will allocate the 1496 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1497 ** size of each lookaside buffer slot. ^The third argument is the number of 1498 ** slots. The size of the buffer in the first argument must be greater than 1499 ** or equal to the product of the second and third arguments. The buffer 1500 ** must be aligned to an 8-byte boundary. ^If the second argument to 1501 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1502 ** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1503 ** configuration for a database connection can only be changed when that 1504 ** connection is not currently using lookaside memory, or in other words 1505 ** when the "current value" returned by 1506 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1507 ** Any attempt to change the lookaside memory configuration when lookaside 1508 ** memory is in use leaves the configuration unchanged and returns 1509 ** [SQLITE_BUSY].)^</dd> 1510 ** 1511 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1512 ** <dd> ^This option is used to enable or disable the enforcement of 1513 ** [foreign key constraints]. There should be two additional arguments. 1514 ** The first argument is an integer which is 0 to disable FK enforcement, 1515 ** positive to enable FK enforcement or negative to leave FK enforcement 1516 ** unchanged. The second parameter is a pointer to an integer into which 1517 ** is written 0 or 1 to indicate whether FK enforcement is off or on 1518 ** following this call. The second parameter may be a NULL pointer, in 1519 ** which case the FK enforcement setting is not reported back. </dd> 1520 ** 1521 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1522 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1523 ** There should be two additional arguments. 1524 ** The first argument is an integer which is 0 to disable triggers, 1525 ** positive to enable triggers or negative to leave the setting unchanged. 1526 ** The second parameter is a pointer to an integer into which 1527 ** is written 0 or 1 to indicate whether triggers are disabled or enabled 1528 ** following this call. The second parameter may be a NULL pointer, in 1529 ** which case the trigger setting is not reported back. </dd> 1530 ** 1531 ** </dl> 1532 */ 1533 #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1534 #define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1535 #define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1536 1537 1538 /* 1539 ** CAPI3REF: Enable Or Disable Extended Result Codes 1540 ** 1541 ** ^The sqlite3_extended_result_codes() routine enables or disables the 1542 ** [extended result codes] feature of SQLite. ^The extended result 1543 ** codes are disabled by default for historical compatibility. 1544 */ 1545 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff); 1546 1547 /* 1548 ** CAPI3REF: Last Insert Rowid 1549 ** 1550 ** ^Each entry in an SQLite table has a unique 64-bit signed 1551 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1552 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1553 ** names are not also used by explicitly declared columns. ^If 1554 ** the table has a column of type [INTEGER PRIMARY KEY] then that column 1555 ** is another alias for the rowid. 1556 ** 1557 ** ^This routine returns the [rowid] of the most recent 1558 ** successful [INSERT] into the database from the [database connection] 1559 ** in the first argument. ^As of SQLite version 3.7.7, this routines 1560 ** records the last insert rowid of both ordinary tables and [virtual tables]. 1561 ** ^If no successful [INSERT]s 1562 ** have ever occurred on that database connection, zero is returned. 1563 ** 1564 ** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1565 ** method, then this routine will return the [rowid] of the inserted 1566 ** row as long as the trigger or virtual table method is running. 1567 ** But once the trigger or virtual table method ends, the value returned 1568 ** by this routine reverts to what it was before the trigger or virtual 1569 ** table method began.)^ 1570 ** 1571 ** ^An [INSERT] that fails due to a constraint violation is not a 1572 ** successful [INSERT] and does not change the value returned by this 1573 ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1574 ** and INSERT OR ABORT make no changes to the return value of this 1575 ** routine when their insertion fails. ^(When INSERT OR REPLACE 1576 ** encounters a constraint violation, it does not fail. The 1577 ** INSERT continues to completion after deleting rows that caused 1578 ** the constraint problem so INSERT OR REPLACE will always change 1579 ** the return value of this interface.)^ 1580 ** 1581 ** ^For the purposes of this routine, an [INSERT] is considered to 1582 ** be successful even if it is subsequently rolled back. 1583 ** 1584 ** This function is accessible to SQL statements via the 1585 ** [last_insert_rowid() SQL function]. 1586 ** 1587 ** If a separate thread performs a new [INSERT] on the same 1588 ** database connection while the [sqlite3_last_insert_rowid()] 1589 ** function is running and thus changes the last insert [rowid], 1590 ** then the value returned by [sqlite3_last_insert_rowid()] is 1591 ** unpredictable and might not equal either the old or the new 1592 ** last insert [rowid]. 1593 */ 1594 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1595 1596 /* 1597 ** CAPI3REF: Count The Number Of Rows Modified 1598 ** 1599 ** ^This function returns the number of database rows that were changed 1600 ** or inserted or deleted by the most recently completed SQL statement 1601 ** on the [database connection] specified by the first parameter. 1602 ** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1603 ** or [DELETE] statement are counted. Auxiliary changes caused by 1604 ** triggers or [foreign key actions] are not counted.)^ Use the 1605 ** [sqlite3_total_changes()] function to find the total number of changes 1606 ** including changes caused by triggers and foreign key actions. 1607 ** 1608 ** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1609 ** are not counted. Only real table changes are counted. 1610 ** 1611 ** ^(A "row change" is a change to a single row of a single table 1612 ** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1613 ** are changed as side effects of [REPLACE] constraint resolution, 1614 ** rollback, ABORT processing, [DROP TABLE], or by any other 1615 ** mechanisms do not count as direct row changes.)^ 1616 ** 1617 ** A "trigger context" is a scope of execution that begins and 1618 ** ends with the script of a [CREATE TRIGGER | trigger]. 1619 ** Most SQL statements are 1620 ** evaluated outside of any trigger. This is the "top level" 1621 ** trigger context. If a trigger fires from the top level, a 1622 ** new trigger context is entered for the duration of that one 1623 ** trigger. Subtriggers create subcontexts for their duration. 1624 ** 1625 ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1626 ** not create a new trigger context. 1627 ** 1628 ** ^This function returns the number of direct row changes in the 1629 ** most recent INSERT, UPDATE, or DELETE statement within the same 1630 ** trigger context. 1631 ** 1632 ** ^Thus, when called from the top level, this function returns the 1633 ** number of changes in the most recent INSERT, UPDATE, or DELETE 1634 ** that also occurred at the top level. ^(Within the body of a trigger, 1635 ** the sqlite3_changes() interface can be called to find the number of 1636 ** changes in the most recently completed INSERT, UPDATE, or DELETE 1637 ** statement within the body of the same trigger. 1638 ** However, the number returned does not include changes 1639 ** caused by subtriggers since those have their own context.)^ 1640 ** 1641 ** See also the [sqlite3_total_changes()] interface, the 1642 ** [count_changes pragma], and the [changes() SQL function]. 1643 ** 1644 ** If a separate thread makes changes on the same database connection 1645 ** while [sqlite3_changes()] is running then the value returned 1646 ** is unpredictable and not meaningful. 1647 */ 1648 SQLITE_API int sqlite3_changes(sqlite3*); 1649 1650 /* 1651 ** CAPI3REF: Total Number Of Rows Modified 1652 ** 1653 ** ^This function returns the number of row changes caused by [INSERT], 1654 ** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1655 ** ^(The count returned by sqlite3_total_changes() includes all changes 1656 ** from all [CREATE TRIGGER | trigger] contexts and changes made by 1657 ** [foreign key actions]. However, 1658 ** the count does not include changes used to implement [REPLACE] constraints, 1659 ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1660 ** count does not include rows of views that fire an [INSTEAD OF trigger], 1661 ** though if the INSTEAD OF trigger makes changes of its own, those changes 1662 ** are counted.)^ 1663 ** ^The sqlite3_total_changes() function counts the changes as soon as 1664 ** the statement that makes them is completed (when the statement handle 1665 ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1666 ** 1667 ** See also the [sqlite3_changes()] interface, the 1668 ** [count_changes pragma], and the [total_changes() SQL function]. 1669 ** 1670 ** If a separate thread makes changes on the same database connection 1671 ** while [sqlite3_total_changes()] is running then the value 1672 ** returned is unpredictable and not meaningful. 1673 */ 1674 SQLITE_API int sqlite3_total_changes(sqlite3*); 1675 1676 /* 1677 ** CAPI3REF: Interrupt A Long-Running Query 1678 ** 1679 ** ^This function causes any pending database operation to abort and 1680 ** return at its earliest opportunity. This routine is typically 1681 ** called in response to a user action such as pressing "Cancel" 1682 ** or Ctrl-C where the user wants a long query operation to halt 1683 ** immediately. 1684 ** 1685 ** ^It is safe to call this routine from a thread different from the 1686 ** thread that is currently running the database operation. But it 1687 ** is not safe to call this routine with a [database connection] that 1688 ** is closed or might close before sqlite3_interrupt() returns. 1689 ** 1690 ** ^If an SQL operation is very nearly finished at the time when 1691 ** sqlite3_interrupt() is called, then it might not have an opportunity 1692 ** to be interrupted and might continue to completion. 1693 ** 1694 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1695 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1696 ** that is inside an explicit transaction, then the entire transaction 1697 ** will be rolled back automatically. 1698 ** 1699 ** ^The sqlite3_interrupt(D) call is in effect until all currently running 1700 ** SQL statements on [database connection] D complete. ^Any new SQL statements 1701 ** that are started after the sqlite3_interrupt() call and before the 1702 ** running statements reaches zero are interrupted as if they had been 1703 ** running prior to the sqlite3_interrupt() call. ^New SQL statements 1704 ** that are started after the running statement count reaches zero are 1705 ** not effected by the sqlite3_interrupt(). 1706 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1707 ** SQL statements is a no-op and has no effect on SQL statements 1708 ** that are started after the sqlite3_interrupt() call returns. 1709 ** 1710 ** If the database connection closes while [sqlite3_interrupt()] 1711 ** is running then bad things will likely happen. 1712 */ 1713 SQLITE_API void sqlite3_interrupt(sqlite3*); 1714 1715 /* 1716 ** CAPI3REF: Determine If An SQL Statement Is Complete 1717 ** 1718 ** These routines are useful during command-line input to determine if the 1719 ** currently entered text seems to form a complete SQL statement or 1720 ** if additional input is needed before sending the text into 1721 ** SQLite for parsing. ^These routines return 1 if the input string 1722 ** appears to be a complete SQL statement. ^A statement is judged to be 1723 ** complete if it ends with a semicolon token and is not a prefix of a 1724 ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1725 ** string literals or quoted identifier names or comments are not 1726 ** independent tokens (they are part of the token in which they are 1727 ** embedded) and thus do not count as a statement terminator. ^Whitespace 1728 ** and comments that follow the final semicolon are ignored. 1729 ** 1730 ** ^These routines return 0 if the statement is incomplete. ^If a 1731 ** memory allocation fails, then SQLITE_NOMEM is returned. 1732 ** 1733 ** ^These routines do not parse the SQL statements thus 1734 ** will not detect syntactically incorrect SQL. 1735 ** 1736 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1737 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1738 ** automatically by sqlite3_complete16(). If that initialization fails, 1739 ** then the return value from sqlite3_complete16() will be non-zero 1740 ** regardless of whether or not the input SQL is complete.)^ 1741 ** 1742 ** The input to [sqlite3_complete()] must be a zero-terminated 1743 ** UTF-8 string. 1744 ** 1745 ** The input to [sqlite3_complete16()] must be a zero-terminated 1746 ** UTF-16 string in native byte order. 1747 */ 1748 SQLITE_API int sqlite3_complete(const char *sql); 1749 SQLITE_API int sqlite3_complete16(const void *sql); 1750 1751 /* 1752 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1753 ** 1754 ** ^This routine sets a callback function that might be invoked whenever 1755 ** an attempt is made to open a database table that another thread 1756 ** or process has locked. 1757 ** 1758 ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1759 ** is returned immediately upon encountering the lock. ^If the busy callback 1760 ** is not NULL, then the callback might be invoked with two arguments. 1761 ** 1762 ** ^The first argument to the busy handler is a copy of the void* pointer which 1763 ** is the third argument to sqlite3_busy_handler(). ^The second argument to 1764 ** the busy handler callback is the number of times that the busy handler has 1765 ** been invoked for this locking event. ^If the 1766 ** busy callback returns 0, then no additional attempts are made to 1767 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1768 ** ^If the callback returns non-zero, then another attempt 1769 ** is made to open the database for reading and the cycle repeats. 1770 ** 1771 ** The presence of a busy handler does not guarantee that it will be invoked 1772 ** when there is lock contention. ^If SQLite determines that invoking the busy 1773 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1774 ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1775 ** Consider a scenario where one process is holding a read lock that 1776 ** it is trying to promote to a reserved lock and 1777 ** a second process is holding a reserved lock that it is trying 1778 ** to promote to an exclusive lock. The first process cannot proceed 1779 ** because it is blocked by the second and the second process cannot 1780 ** proceed because it is blocked by the first. If both processes 1781 ** invoke the busy handlers, neither will make any progress. Therefore, 1782 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1783 ** will induce the first process to release its read lock and allow 1784 ** the second process to proceed. 1785 ** 1786 ** ^The default busy callback is NULL. 1787 ** 1788 ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1789 ** when SQLite is in the middle of a large transaction where all the 1790 ** changes will not fit into the in-memory cache. SQLite will 1791 ** already hold a RESERVED lock on the database file, but it needs 1792 ** to promote this lock to EXCLUSIVE so that it can spill cache 1793 ** pages into the database file without harm to concurrent 1794 ** readers. ^If it is unable to promote the lock, then the in-memory 1795 ** cache will be left in an inconsistent state and so the error 1796 ** code is promoted from the relatively benign [SQLITE_BUSY] to 1797 ** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 1798 ** forces an automatic rollback of the changes. See the 1799 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1800 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1801 ** this is important. 1802 ** 1803 ** ^(There can only be a single busy handler defined for each 1804 ** [database connection]. Setting a new busy handler clears any 1805 ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 1806 ** will also set or clear the busy handler. 1807 ** 1808 ** The busy callback should not take any actions which modify the 1809 ** database connection that invoked the busy handler. Any such actions 1810 ** result in undefined behavior. 1811 ** 1812 ** A busy handler must not close the database connection 1813 ** or [prepared statement] that invoked the busy handler. 1814 */ 1815 SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1816 1817 /* 1818 ** CAPI3REF: Set A Busy Timeout 1819 ** 1820 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1821 ** for a specified amount of time when a table is locked. ^The handler 1822 ** will sleep multiple times until at least "ms" milliseconds of sleeping 1823 ** have accumulated. ^After at least "ms" milliseconds of sleeping, 1824 ** the handler returns 0 which causes [sqlite3_step()] to return 1825 ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1826 ** 1827 ** ^Calling this routine with an argument less than or equal to zero 1828 ** turns off all busy handlers. 1829 ** 1830 ** ^(There can only be a single busy handler for a particular 1831 ** [database connection] any any given moment. If another busy handler 1832 ** was defined (using [sqlite3_busy_handler()]) prior to calling 1833 ** this routine, that other busy handler is cleared.)^ 1834 */ 1835 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms); 1836 1837 /* 1838 ** CAPI3REF: Convenience Routines For Running Queries 1839 ** 1840 ** This is a legacy interface that is preserved for backwards compatibility. 1841 ** Use of this interface is not recommended. 1842 ** 1843 ** Definition: A <b>result table</b> is memory data structure created by the 1844 ** [sqlite3_get_table()] interface. A result table records the 1845 ** complete query results from one or more queries. 1846 ** 1847 ** The table conceptually has a number of rows and columns. But 1848 ** these numbers are not part of the result table itself. These 1849 ** numbers are obtained separately. Let N be the number of rows 1850 ** and M be the number of columns. 1851 ** 1852 ** A result table is an array of pointers to zero-terminated UTF-8 strings. 1853 ** There are (N+1)*M elements in the array. The first M pointers point 1854 ** to zero-terminated strings that contain the names of the columns. 1855 ** The remaining entries all point to query results. NULL values result 1856 ** in NULL pointers. All other values are in their UTF-8 zero-terminated 1857 ** string representation as returned by [sqlite3_column_text()]. 1858 ** 1859 ** A result table might consist of one or more memory allocations. 1860 ** It is not safe to pass a result table directly to [sqlite3_free()]. 1861 ** A result table should be deallocated using [sqlite3_free_table()]. 1862 ** 1863 ** ^(As an example of the result table format, suppose a query result 1864 ** is as follows: 1865 ** 1866 ** <blockquote><pre> 1867 ** Name | Age 1868 ** ----------------------- 1869 ** Alice | 43 1870 ** Bob | 28 1871 ** Cindy | 21 1872 ** </pre></blockquote> 1873 ** 1874 ** There are two column (M==2) and three rows (N==3). Thus the 1875 ** result table has 8 entries. Suppose the result table is stored 1876 ** in an array names azResult. Then azResult holds this content: 1877 ** 1878 ** <blockquote><pre> 1879 ** azResult[0] = "Name"; 1880 ** azResult[1] = "Age"; 1881 ** azResult[2] = "Alice"; 1882 ** azResult[3] = "43"; 1883 ** azResult[4] = "Bob"; 1884 ** azResult[5] = "28"; 1885 ** azResult[6] = "Cindy"; 1886 ** azResult[7] = "21"; 1887 ** </pre></blockquote>)^ 1888 ** 1889 ** ^The sqlite3_get_table() function evaluates one or more 1890 ** semicolon-separated SQL statements in the zero-terminated UTF-8 1891 ** string of its 2nd parameter and returns a result table to the 1892 ** pointer given in its 3rd parameter. 1893 ** 1894 ** After the application has finished with the result from sqlite3_get_table(), 1895 ** it must pass the result table pointer to sqlite3_free_table() in order to 1896 ** release the memory that was malloced. Because of the way the 1897 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1898 ** function must not try to call [sqlite3_free()] directly. Only 1899 ** [sqlite3_free_table()] is able to release the memory properly and safely. 1900 ** 1901 ** The sqlite3_get_table() interface is implemented as a wrapper around 1902 ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 1903 ** to any internal data structures of SQLite. It uses only the public 1904 ** interface defined here. As a consequence, errors that occur in the 1905 ** wrapper layer outside of the internal [sqlite3_exec()] call are not 1906 ** reflected in subsequent calls to [sqlite3_errcode()] or 1907 ** [sqlite3_errmsg()]. 1908 */ 1909 SQLITE_API int sqlite3_get_table( 1910 sqlite3 *db, /* An open database */ 1911 const char *zSql, /* SQL to be evaluated */ 1912 char ***pazResult, /* Results of the query */ 1913 int *pnRow, /* Number of result rows written here */ 1914 int *pnColumn, /* Number of result columns written here */ 1915 char **pzErrmsg /* Error msg written here */ 1916 ); 1917 SQLITE_API void sqlite3_free_table(char **result); 1918 1919 /* 1920 ** CAPI3REF: Formatted String Printing Functions 1921 ** 1922 ** These routines are work-alikes of the "printf()" family of functions 1923 ** from the standard C library. 1924 ** 1925 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 1926 ** results into memory obtained from [sqlite3_malloc()]. 1927 ** The strings returned by these two routines should be 1928 ** released by [sqlite3_free()]. ^Both routines return a 1929 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 1930 ** memory to hold the resulting string. 1931 ** 1932 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 1933 ** the standard C library. The result is written into the 1934 ** buffer supplied as the second parameter whose size is given by 1935 ** the first parameter. Note that the order of the 1936 ** first two parameters is reversed from snprintf().)^ This is an 1937 ** historical accident that cannot be fixed without breaking 1938 ** backwards compatibility. ^(Note also that sqlite3_snprintf() 1939 ** returns a pointer to its buffer instead of the number of 1940 ** characters actually written into the buffer.)^ We admit that 1941 ** the number of characters written would be a more useful return 1942 ** value but we cannot change the implementation of sqlite3_snprintf() 1943 ** now without breaking compatibility. 1944 ** 1945 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 1946 ** guarantees that the buffer is always zero-terminated. ^The first 1947 ** parameter "n" is the total size of the buffer, including space for 1948 ** the zero terminator. So the longest string that can be completely 1949 ** written will be n-1 characters. 1950 ** 1951 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 1952 ** 1953 ** These routines all implement some additional formatting 1954 ** options that are useful for constructing SQL statements. 1955 ** All of the usual printf() formatting options apply. In addition, there 1956 ** is are "%q", "%Q", and "%z" options. 1957 ** 1958 ** ^(The %q option works like %s in that it substitutes a null-terminated 1959 ** string from the argument list. But %q also doubles every '\'' character. 1960 ** %q is designed for use inside a string literal.)^ By doubling each '\'' 1961 ** character it escapes that character and allows it to be inserted into 1962 ** the string. 1963 ** 1964 ** For example, assume the string variable zText contains text as follows: 1965 ** 1966 ** <blockquote><pre> 1967 ** char *zText = "It's a happy day!"; 1968 ** </pre></blockquote> 1969 ** 1970 ** One can use this text in an SQL statement as follows: 1971 ** 1972 ** <blockquote><pre> 1973 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 1974 ** sqlite3_exec(db, zSQL, 0, 0, 0); 1975 ** sqlite3_free(zSQL); 1976 ** </pre></blockquote> 1977 ** 1978 ** Because the %q format string is used, the '\'' character in zText 1979 ** is escaped and the SQL generated is as follows: 1980 ** 1981 ** <blockquote><pre> 1982 ** INSERT INTO table1 VALUES('It''s a happy day!') 1983 ** </pre></blockquote> 1984 ** 1985 ** This is correct. Had we used %s instead of %q, the generated SQL 1986 ** would have looked like this: 1987 ** 1988 ** <blockquote><pre> 1989 ** INSERT INTO table1 VALUES('It's a happy day!'); 1990 ** </pre></blockquote> 1991 ** 1992 ** This second example is an SQL syntax error. As a general rule you should 1993 ** always use %q instead of %s when inserting text into a string literal. 1994 ** 1995 ** ^(The %Q option works like %q except it also adds single quotes around 1996 ** the outside of the total string. Additionally, if the parameter in the 1997 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 1998 ** single quotes).)^ So, for example, one could say: 1999 ** 2000 ** <blockquote><pre> 2001 ** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2002 ** sqlite3_exec(db, zSQL, 0, 0, 0); 2003 ** sqlite3_free(zSQL); 2004 ** </pre></blockquote> 2005 ** 2006 ** The code above will render a correct SQL statement in the zSQL 2007 ** variable even if the zText variable is a NULL pointer. 2008 ** 2009 ** ^(The "%z" formatting option works like "%s" but with the 2010 ** addition that after the string has been read and copied into 2011 ** the result, [sqlite3_free()] is called on the input string.)^ 2012 */ 2013 SQLITE_API char *sqlite3_mprintf(const char*,...); 2014 SQLITE_API char *sqlite3_vmprintf(const char*, va_list); 2015 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...); 2016 SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2017 2018 /* 2019 ** CAPI3REF: Memory Allocation Subsystem 2020 ** 2021 ** The SQLite core uses these three routines for all of its own 2022 ** internal memory allocation needs. "Core" in the previous sentence 2023 ** does not include operating-system specific VFS implementation. The 2024 ** Windows VFS uses native malloc() and free() for some operations. 2025 ** 2026 ** ^The sqlite3_malloc() routine returns a pointer to a block 2027 ** of memory at least N bytes in length, where N is the parameter. 2028 ** ^If sqlite3_malloc() is unable to obtain sufficient free 2029 ** memory, it returns a NULL pointer. ^If the parameter N to 2030 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2031 ** a NULL pointer. 2032 ** 2033 ** ^Calling sqlite3_free() with a pointer previously returned 2034 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2035 ** that it might be reused. ^The sqlite3_free() routine is 2036 ** a no-op if is called with a NULL pointer. Passing a NULL pointer 2037 ** to sqlite3_free() is harmless. After being freed, memory 2038 ** should neither be read nor written. Even reading previously freed 2039 ** memory might result in a segmentation fault or other severe error. 2040 ** Memory corruption, a segmentation fault, or other severe error 2041 ** might result if sqlite3_free() is called with a non-NULL pointer that 2042 ** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2043 ** 2044 ** ^(The sqlite3_realloc() interface attempts to resize a 2045 ** prior memory allocation to be at least N bytes, where N is the 2046 ** second parameter. The memory allocation to be resized is the first 2047 ** parameter.)^ ^ If the first parameter to sqlite3_realloc() 2048 ** is a NULL pointer then its behavior is identical to calling 2049 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 2050 ** ^If the second parameter to sqlite3_realloc() is zero or 2051 ** negative then the behavior is exactly the same as calling 2052 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 2053 ** ^sqlite3_realloc() returns a pointer to a memory allocation 2054 ** of at least N bytes in size or NULL if sufficient memory is unavailable. 2055 ** ^If M is the size of the prior allocation, then min(N,M) bytes 2056 ** of the prior allocation are copied into the beginning of buffer returned 2057 ** by sqlite3_realloc() and the prior allocation is freed. 2058 ** ^If sqlite3_realloc() returns NULL, then the prior allocation 2059 ** is not freed. 2060 ** 2061 ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 2062 ** is always aligned to at least an 8 byte boundary, or to a 2063 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2064 ** option is used. 2065 ** 2066 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2067 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2068 ** implementation of these routines to be omitted. That capability 2069 ** is no longer provided. Only built-in memory allocators can be used. 2070 ** 2071 ** The Windows OS interface layer calls 2072 ** the system malloc() and free() directly when converting 2073 ** filenames between the UTF-8 encoding used by SQLite 2074 ** and whatever filename encoding is used by the particular Windows 2075 ** installation. Memory allocation errors are detected, but 2076 ** they are reported back as [SQLITE_CANTOPEN] or 2077 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2078 ** 2079 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2080 ** must be either NULL or else pointers obtained from a prior 2081 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2082 ** not yet been released. 2083 ** 2084 ** The application must not read or write any part of 2085 ** a block of memory after it has been released using 2086 ** [sqlite3_free()] or [sqlite3_realloc()]. 2087 */ 2088 SQLITE_API void *sqlite3_malloc(int); 2089 SQLITE_API void *sqlite3_realloc(void*, int); 2090 SQLITE_API void sqlite3_free(void*); 2091 2092 /* 2093 ** CAPI3REF: Memory Allocator Statistics 2094 ** 2095 ** SQLite provides these two interfaces for reporting on the status 2096 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2097 ** routines, which form the built-in memory allocation subsystem. 2098 ** 2099 ** ^The [sqlite3_memory_used()] routine returns the number of bytes 2100 ** of memory currently outstanding (malloced but not freed). 2101 ** ^The [sqlite3_memory_highwater()] routine returns the maximum 2102 ** value of [sqlite3_memory_used()] since the high-water mark 2103 ** was last reset. ^The values returned by [sqlite3_memory_used()] and 2104 ** [sqlite3_memory_highwater()] include any overhead 2105 ** added by SQLite in its implementation of [sqlite3_malloc()], 2106 ** but not overhead added by the any underlying system library 2107 ** routines that [sqlite3_malloc()] may call. 2108 ** 2109 ** ^The memory high-water mark is reset to the current value of 2110 ** [sqlite3_memory_used()] if and only if the parameter to 2111 ** [sqlite3_memory_highwater()] is true. ^The value returned 2112 ** by [sqlite3_memory_highwater(1)] is the high-water mark 2113 ** prior to the reset. 2114 */ 2115 SQLITE_API sqlite3_int64 sqlite3_memory_used(void); 2116 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2117 2118 /* 2119 ** CAPI3REF: Pseudo-Random Number Generator 2120 ** 2121 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2122 ** select random [ROWID | ROWIDs] when inserting new records into a table that 2123 ** already uses the largest possible [ROWID]. The PRNG is also used for 2124 ** the build-in random() and randomblob() SQL functions. This interface allows 2125 ** applications to access the same PRNG for other purposes. 2126 ** 2127 ** ^A call to this routine stores N bytes of randomness into buffer P. 2128 ** 2129 ** ^The first time this routine is invoked (either internally or by 2130 ** the application) the PRNG is seeded using randomness obtained 2131 ** from the xRandomness method of the default [sqlite3_vfs] object. 2132 ** ^On all subsequent invocations, the pseudo-randomness is generated 2133 ** internally and without recourse to the [sqlite3_vfs] xRandomness 2134 ** method. 2135 */ 2136 SQLITE_API void sqlite3_randomness(int N, void *P); 2137 2138 /* 2139 ** CAPI3REF: Compile-Time Authorization Callbacks 2140 ** 2141 ** ^This routine registers an authorizer callback with a particular 2142 ** [database connection], supplied in the first argument. 2143 ** ^The authorizer callback is invoked as SQL statements are being compiled 2144 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2145 ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2146 ** points during the compilation process, as logic is being created 2147 ** to perform various actions, the authorizer callback is invoked to 2148 ** see if those actions are allowed. ^The authorizer callback should 2149 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2150 ** specific action but allow the SQL statement to continue to be 2151 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2152 ** rejected with an error. ^If the authorizer callback returns 2153 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2154 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2155 ** the authorizer will fail with an error message. 2156 ** 2157 ** When the callback returns [SQLITE_OK], that means the operation 2158 ** requested is ok. ^When the callback returns [SQLITE_DENY], the 2159 ** [sqlite3_prepare_v2()] or equivalent call that triggered the 2160 ** authorizer will fail with an error message explaining that 2161 ** access is denied. 2162 ** 2163 ** ^The first parameter to the authorizer callback is a copy of the third 2164 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2165 ** to the callback is an integer [SQLITE_COPY | action code] that specifies 2166 ** the particular action to be authorized. ^The third through sixth parameters 2167 ** to the callback are zero-terminated strings that contain additional 2168 ** details about the action to be authorized. 2169 ** 2170 ** ^If the action code is [SQLITE_READ] 2171 ** and the callback returns [SQLITE_IGNORE] then the 2172 ** [prepared statement] statement is constructed to substitute 2173 ** a NULL value in place of the table column that would have 2174 ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2175 ** return can be used to deny an untrusted user access to individual 2176 ** columns of a table. 2177 ** ^If the action code is [SQLITE_DELETE] and the callback returns 2178 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2179 ** [truncate optimization] is disabled and all rows are deleted individually. 2180 ** 2181 ** An authorizer is used when [sqlite3_prepare | preparing] 2182 ** SQL statements from an untrusted source, to ensure that the SQL statements 2183 ** do not try to access data they are not allowed to see, or that they do not 2184 ** try to execute malicious statements that damage the database. For 2185 ** example, an application may allow a user to enter arbitrary 2186 ** SQL queries for evaluation by a database. But the application does 2187 ** not want the user to be able to make arbitrary changes to the 2188 ** database. An authorizer could then be put in place while the 2189 ** user-entered SQL is being [sqlite3_prepare | prepared] that 2190 ** disallows everything except [SELECT] statements. 2191 ** 2192 ** Applications that need to process SQL from untrusted sources 2193 ** might also consider lowering resource limits using [sqlite3_limit()] 2194 ** and limiting database size using the [max_page_count] [PRAGMA] 2195 ** in addition to using an authorizer. 2196 ** 2197 ** ^(Only a single authorizer can be in place on a database connection 2198 ** at a time. Each call to sqlite3_set_authorizer overrides the 2199 ** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2200 ** The authorizer is disabled by default. 2201 ** 2202 ** The authorizer callback must not do anything that will modify 2203 ** the database connection that invoked the authorizer callback. 2204 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2205 ** database connections for the meaning of "modify" in this paragraph. 2206 ** 2207 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2208 ** statement might be re-prepared during [sqlite3_step()] due to a 2209 ** schema change. Hence, the application should ensure that the 2210 ** correct authorizer callback remains in place during the [sqlite3_step()]. 2211 ** 2212 ** ^Note that the authorizer callback is invoked only during 2213 ** [sqlite3_prepare()] or its variants. Authorization is not 2214 ** performed during statement evaluation in [sqlite3_step()], unless 2215 ** as stated in the previous paragraph, sqlite3_step() invokes 2216 ** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2217 */ 2218 SQLITE_API int sqlite3_set_authorizer( 2219 sqlite3*, 2220 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2221 void *pUserData 2222 ); 2223 2224 /* 2225 ** CAPI3REF: Authorizer Return Codes 2226 ** 2227 ** The [sqlite3_set_authorizer | authorizer callback function] must 2228 ** return either [SQLITE_OK] or one of these two constants in order 2229 ** to signal SQLite whether or not the action is permitted. See the 2230 ** [sqlite3_set_authorizer | authorizer documentation] for additional 2231 ** information. 2232 ** 2233 ** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code] 2234 ** from the [sqlite3_vtab_on_conflict()] interface. 2235 */ 2236 #define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2237 #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2238 2239 /* 2240 ** CAPI3REF: Authorizer Action Codes 2241 ** 2242 ** The [sqlite3_set_authorizer()] interface registers a callback function 2243 ** that is invoked to authorize certain SQL statement actions. The 2244 ** second parameter to the callback is an integer code that specifies 2245 ** what action is being authorized. These are the integer action codes that 2246 ** the authorizer callback may be passed. 2247 ** 2248 ** These action code values signify what kind of operation is to be 2249 ** authorized. The 3rd and 4th parameters to the authorization 2250 ** callback function will be parameters or NULL depending on which of these 2251 ** codes is used as the second parameter. ^(The 5th parameter to the 2252 ** authorizer callback is the name of the database ("main", "temp", 2253 ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2254 ** is the name of the inner-most trigger or view that is responsible for 2255 ** the access attempt or NULL if this access attempt is directly from 2256 ** top-level SQL code. 2257 */ 2258 /******************************************* 3rd ************ 4th ***********/ 2259 #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2260 #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2261 #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2262 #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2263 #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2264 #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2265 #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2266 #define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2267 #define SQLITE_DELETE 9 /* Table Name NULL */ 2268 #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2269 #define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2270 #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2271 #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2272 #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2273 #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2274 #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2275 #define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2276 #define SQLITE_INSERT 18 /* Table Name NULL */ 2277 #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2278 #define SQLITE_READ 20 /* Table Name Column Name */ 2279 #define SQLITE_SELECT 21 /* NULL NULL */ 2280 #define SQLITE_TRANSACTION 22 /* Operation NULL */ 2281 #define SQLITE_UPDATE 23 /* Table Name Column Name */ 2282 #define SQLITE_ATTACH 24 /* Filename NULL */ 2283 #define SQLITE_DETACH 25 /* Database Name NULL */ 2284 #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2285 #define SQLITE_REINDEX 27 /* Index Name NULL */ 2286 #define SQLITE_ANALYZE 28 /* Table Name NULL */ 2287 #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2288 #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2289 #define SQLITE_FUNCTION 31 /* NULL Function Name */ 2290 #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2291 #define SQLITE_COPY 0 /* No longer used */ 2292 2293 /* 2294 ** CAPI3REF: Tracing And Profiling Functions 2295 ** 2296 ** These routines register callback functions that can be used for 2297 ** tracing and profiling the execution of SQL statements. 2298 ** 2299 ** ^The callback function registered by sqlite3_trace() is invoked at 2300 ** various times when an SQL statement is being run by [sqlite3_step()]. 2301 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2302 ** SQL statement text as the statement first begins executing. 2303 ** ^(Additional sqlite3_trace() callbacks might occur 2304 ** as each triggered subprogram is entered. The callbacks for triggers 2305 ** contain a UTF-8 SQL comment that identifies the trigger.)^ 2306 ** 2307 ** ^The callback function registered by sqlite3_profile() is invoked 2308 ** as each SQL statement finishes. ^The profile callback contains 2309 ** the original statement text and an estimate of wall-clock time 2310 ** of how long that statement took to run. ^The profile callback 2311 ** time is in units of nanoseconds, however the current implementation 2312 ** is only capable of millisecond resolution so the six least significant 2313 ** digits in the time are meaningless. Future versions of SQLite 2314 ** might provide greater resolution on the profiler callback. The 2315 ** sqlite3_profile() function is considered experimental and is 2316 ** subject to change in future versions of SQLite. 2317 */ 2318 SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2319 SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2320 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2321 2322 /* 2323 ** CAPI3REF: Query Progress Callbacks 2324 ** 2325 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2326 ** function X to be invoked periodically during long running calls to 2327 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2328 ** database connection D. An example use for this 2329 ** interface is to keep a GUI updated during a large query. 2330 ** 2331 ** ^The parameter P is passed through as the only parameter to the 2332 ** callback function X. ^The parameter N is the number of 2333 ** [virtual machine instructions] that are evaluated between successive 2334 ** invocations of the callback X. 2335 ** 2336 ** ^Only a single progress handler may be defined at one time per 2337 ** [database connection]; setting a new progress handler cancels the 2338 ** old one. ^Setting parameter X to NULL disables the progress handler. 2339 ** ^The progress handler is also disabled by setting N to a value less 2340 ** than 1. 2341 ** 2342 ** ^If the progress callback returns non-zero, the operation is 2343 ** interrupted. This feature can be used to implement a 2344 ** "Cancel" button on a GUI progress dialog box. 2345 ** 2346 ** The progress handler callback must not do anything that will modify 2347 ** the database connection that invoked the progress handler. 2348 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2349 ** database connections for the meaning of "modify" in this paragraph. 2350 ** 2351 */ 2352 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2353 2354 /* 2355 ** CAPI3REF: Opening A New Database Connection 2356 ** 2357 ** ^These routines open an SQLite database file as specified by the 2358 ** filename argument. ^The filename argument is interpreted as UTF-8 for 2359 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2360 ** order for sqlite3_open16(). ^(A [database connection] handle is usually 2361 ** returned in *ppDb, even if an error occurs. The only exception is that 2362 ** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2363 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2364 ** object.)^ ^(If the database is opened (and/or created) successfully, then 2365 ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2366 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2367 ** an English language description of the error following a failure of any 2368 ** of the sqlite3_open() routines. 2369 ** 2370 ** ^The default encoding for the database will be UTF-8 if 2371 ** sqlite3_open() or sqlite3_open_v2() is called and 2372 ** UTF-16 in the native byte order if sqlite3_open16() is used. 2373 ** 2374 ** Whether or not an error occurs when it is opened, resources 2375 ** associated with the [database connection] handle should be released by 2376 ** passing it to [sqlite3_close()] when it is no longer required. 2377 ** 2378 ** The sqlite3_open_v2() interface works like sqlite3_open() 2379 ** except that it accepts two additional parameters for additional control 2380 ** over the new database connection. ^(The flags parameter to 2381 ** sqlite3_open_v2() can take one of 2382 ** the following three values, optionally combined with the 2383 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2384 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2385 ** 2386 ** <dl> 2387 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2388 ** <dd>The database is opened in read-only mode. If the database does not 2389 ** already exist, an error is returned.</dd>)^ 2390 ** 2391 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2392 ** <dd>The database is opened for reading and writing if possible, or reading 2393 ** only if the file is write protected by the operating system. In either 2394 ** case the database must already exist, otherwise an error is returned.</dd>)^ 2395 ** 2396 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2397 ** <dd>The database is opened for reading and writing, and is created if 2398 ** it does not already exist. This is the behavior that is always used for 2399 ** sqlite3_open() and sqlite3_open16().</dd>)^ 2400 ** </dl> 2401 ** 2402 ** If the 3rd parameter to sqlite3_open_v2() is not one of the 2403 ** combinations shown above optionally combined with other 2404 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2405 ** then the behavior is undefined. 2406 ** 2407 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2408 ** opens in the multi-thread [threading mode] as long as the single-thread 2409 ** mode has not been set at compile-time or start-time. ^If the 2410 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2411 ** in the serialized [threading mode] unless single-thread was 2412 ** previously selected at compile-time or start-time. 2413 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2414 ** eligible to use [shared cache mode], regardless of whether or not shared 2415 ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2416 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2417 ** participate in [shared cache mode] even if it is enabled. 2418 ** 2419 ** ^The fourth parameter to sqlite3_open_v2() is the name of the 2420 ** [sqlite3_vfs] object that defines the operating system interface that 2421 ** the new database connection should use. ^If the fourth parameter is 2422 ** a NULL pointer then the default [sqlite3_vfs] object is used. 2423 ** 2424 ** ^If the filename is ":memory:", then a private, temporary in-memory database 2425 ** is created for the connection. ^This in-memory database will vanish when 2426 ** the database connection is closed. Future versions of SQLite might 2427 ** make use of additional special filenames that begin with the ":" character. 2428 ** It is recommended that when a database filename actually does begin with 2429 ** a ":" character you should prefix the filename with a pathname such as 2430 ** "./" to avoid ambiguity. 2431 ** 2432 ** ^If the filename is an empty string, then a private, temporary 2433 ** on-disk database will be created. ^This private database will be 2434 ** automatically deleted as soon as the database connection is closed. 2435 ** 2436 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2437 ** 2438 ** ^If [URI filename] interpretation is enabled, and the filename argument 2439 ** begins with "file:", then the filename is interpreted as a URI. ^URI 2440 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2441 ** set in the fourth argument to sqlite3_open_v2(), or if it has 2442 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2443 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2444 ** As of SQLite version 3.7.7, URI filename interpretation is turned off 2445 ** by default, but future releases of SQLite might enable URI filename 2446 ** interpretation by default. See "[URI filenames]" for additional 2447 ** information. 2448 ** 2449 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2450 ** authority, then it must be either an empty string or the string 2451 ** "localhost". ^If the authority is not an empty string or "localhost", an 2452 ** error is returned to the caller. ^The fragment component of a URI, if 2453 ** present, is ignored. 2454 ** 2455 ** ^SQLite uses the path component of the URI as the name of the disk file 2456 ** which contains the database. ^If the path begins with a '/' character, 2457 ** then it is interpreted as an absolute path. ^If the path does not begin 2458 ** with a '/' (meaning that the authority section is omitted from the URI) 2459 ** then the path is interpreted as a relative path. 2460 ** ^On windows, the first component of an absolute path 2461 ** is a drive specification (e.g. "C:"). 2462 ** 2463 ** [[core URI query parameters]] 2464 ** The query component of a URI may contain parameters that are interpreted 2465 ** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2466 ** SQLite interprets the following three query parameters: 2467 ** 2468 ** <ul> 2469 ** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2470 ** a VFS object that provides the operating system interface that should 2471 ** be used to access the database file on disk. ^If this option is set to 2472 ** an empty string the default VFS object is used. ^Specifying an unknown 2473 ** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2474 ** present, then the VFS specified by the option takes precedence over 2475 ** the value passed as the fourth parameter to sqlite3_open_v2(). 2476 ** 2477 ** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw" or 2478 ** "rwc". Attempting to set it to any other value is an error)^. 2479 ** ^If "ro" is specified, then the database is opened for read-only 2480 ** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2481 ** third argument to sqlite3_prepare_v2(). ^If the mode option is set to 2482 ** "rw", then the database is opened for read-write (but not create) 2483 ** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2484 ** been set. ^Value "rwc" is equivalent to setting both 2485 ** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If sqlite3_open_v2() is 2486 ** used, it is an error to specify a value for the mode parameter that is 2487 ** less restrictive than that specified by the flags passed as the third 2488 ** parameter. 2489 ** 2490 ** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2491 ** "private". ^Setting it to "shared" is equivalent to setting the 2492 ** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2493 ** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2494 ** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2495 ** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2496 ** a URI filename, its value overrides any behaviour requested by setting 2497 ** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2498 ** </ul> 2499 ** 2500 ** ^Specifying an unknown parameter in the query component of a URI is not an 2501 ** error. Future versions of SQLite might understand additional query 2502 ** parameters. See "[query parameters with special meaning to SQLite]" for 2503 ** additional information. 2504 ** 2505 ** [[URI filename examples]] <h3>URI filename examples</h3> 2506 ** 2507 ** <table border="1" align=center cellpadding=5> 2508 ** <tr><th> URI filenames <th> Results 2509 ** <tr><td> file:data.db <td> 2510 ** Open the file "data.db" in the current directory. 2511 ** <tr><td> file:/home/fred/data.db<br> 2512 ** file:///home/fred/data.db <br> 2513 ** file://localhost/home/fred/data.db <br> <td> 2514 ** Open the database file "/home/fred/data.db". 2515 ** <tr><td> file://darkstar/home/fred/data.db <td> 2516 ** An error. "darkstar" is not a recognized authority. 2517 ** <tr><td style="white-space:nowrap"> 2518 ** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2519 ** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2520 ** C:. Note that the %20 escaping in this example is not strictly 2521 ** necessary - space characters can be used literally 2522 ** in URI filenames. 2523 ** <tr><td> file:data.db?mode=ro&cache=private <td> 2524 ** Open file "data.db" in the current directory for read-only access. 2525 ** Regardless of whether or not shared-cache mode is enabled by 2526 ** default, use a private cache. 2527 ** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td> 2528 ** Open file "/home/fred/data.db". Use the special VFS "unix-nolock". 2529 ** <tr><td> file:data.db?mode=readonly <td> 2530 ** An error. "readonly" is not a valid option for the "mode" parameter. 2531 ** </table> 2532 ** 2533 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2534 ** query components of a URI. A hexadecimal escape sequence consists of a 2535 ** percent sign - "%" - followed by exactly two hexadecimal digits 2536 ** specifying an octet value. ^Before the path or query components of a 2537 ** URI filename are interpreted, they are encoded using UTF-8 and all 2538 ** hexadecimal escape sequences replaced by a single byte containing the 2539 ** corresponding octet. If this process generates an invalid UTF-8 encoding, 2540 ** the results are undefined. 2541 ** 2542 ** <b>Note to Windows users:</b> The encoding used for the filename argument 2543 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2544 ** codepage is currently defined. Filenames containing international 2545 ** characters must be converted to UTF-8 prior to passing them into 2546 ** sqlite3_open() or sqlite3_open_v2(). 2547 */ 2548 SQLITE_API int sqlite3_open( 2549 const char *filename, /* Database filename (UTF-8) */ 2550 sqlite3 **ppDb /* OUT: SQLite db handle */ 2551 ); 2552 SQLITE_API int sqlite3_open16( 2553 const void *filename, /* Database filename (UTF-16) */ 2554 sqlite3 **ppDb /* OUT: SQLite db handle */ 2555 ); 2556 SQLITE_API int sqlite3_open_v2( 2557 const char *filename, /* Database filename (UTF-8) */ 2558 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2559 int flags, /* Flags */ 2560 const char *zVfs /* Name of VFS module to use */ 2561 ); 2562 2563 /* 2564 ** CAPI3REF: Obtain Values For URI Parameters 2565 ** 2566 ** This is a utility routine, useful to VFS implementations, that checks 2567 ** to see if a database file was a URI that contained a specific query 2568 ** parameter, and if so obtains the value of the query parameter. 2569 ** 2570 ** The zFilename argument is the filename pointer passed into the xOpen() 2571 ** method of a VFS implementation. The zParam argument is the name of the 2572 ** query parameter we seek. This routine returns the value of the zParam 2573 ** parameter if it exists. If the parameter does not exist, this routine 2574 ** returns a NULL pointer. 2575 ** 2576 ** If the zFilename argument to this function is not a pointer that SQLite 2577 ** passed into the xOpen VFS method, then the behavior of this routine 2578 ** is undefined and probably undesirable. 2579 */ 2580 SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 2581 2582 2583 /* 2584 ** CAPI3REF: Error Codes And Messages 2585 ** 2586 ** ^The sqlite3_errcode() interface returns the numeric [result code] or 2587 ** [extended result code] for the most recent failed sqlite3_* API call 2588 ** associated with a [database connection]. If a prior API call failed 2589 ** but the most recent API call succeeded, the return value from 2590 ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2591 ** interface is the same except that it always returns the 2592 ** [extended result code] even when extended result codes are 2593 ** disabled. 2594 ** 2595 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2596 ** text that describes the error, as either UTF-8 or UTF-16 respectively. 2597 ** ^(Memory to hold the error message string is managed internally. 2598 ** The application does not need to worry about freeing the result. 2599 ** However, the error string might be overwritten or deallocated by 2600 ** subsequent calls to other SQLite interface functions.)^ 2601 ** 2602 ** When the serialized [threading mode] is in use, it might be the 2603 ** case that a second error occurs on a separate thread in between 2604 ** the time of the first error and the call to these interfaces. 2605 ** When that happens, the second error will be reported since these 2606 ** interfaces always report the most recent result. To avoid 2607 ** this, each thread can obtain exclusive use of the [database connection] D 2608 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2609 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2610 ** all calls to the interfaces listed here are completed. 2611 ** 2612 ** If an interface fails with SQLITE_MISUSE, that means the interface 2613 ** was invoked incorrectly by the application. In that case, the 2614 ** error code and message may or may not be set. 2615 */ 2616 SQLITE_API int sqlite3_errcode(sqlite3 *db); 2617 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db); 2618 SQLITE_API const char *sqlite3_errmsg(sqlite3*); 2619 SQLITE_API const void *sqlite3_errmsg16(sqlite3*); 2620 2621 /* 2622 ** CAPI3REF: SQL Statement Object 2623 ** KEYWORDS: {prepared statement} {prepared statements} 2624 ** 2625 ** An instance of this object represents a single SQL statement. 2626 ** This object is variously known as a "prepared statement" or a 2627 ** "compiled SQL statement" or simply as a "statement". 2628 ** 2629 ** The life of a statement object goes something like this: 2630 ** 2631 ** <ol> 2632 ** <li> Create the object using [sqlite3_prepare_v2()] or a related 2633 ** function. 2634 ** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2635 ** interfaces. 2636 ** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2637 ** <li> Reset the statement using [sqlite3_reset()] then go back 2638 ** to step 2. Do this zero or more times. 2639 ** <li> Destroy the object using [sqlite3_finalize()]. 2640 ** </ol> 2641 ** 2642 ** Refer to documentation on individual methods above for additional 2643 ** information. 2644 */ 2645 typedef struct sqlite3_stmt sqlite3_stmt; 2646 2647 /* 2648 ** CAPI3REF: Run-time Limits 2649 ** 2650 ** ^(This interface allows the size of various constructs to be limited 2651 ** on a connection by connection basis. The first parameter is the 2652 ** [database connection] whose limit is to be set or queried. The 2653 ** second parameter is one of the [limit categories] that define a 2654 ** class of constructs to be size limited. The third parameter is the 2655 ** new limit for that construct.)^ 2656 ** 2657 ** ^If the new limit is a negative number, the limit is unchanged. 2658 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 2659 ** [limits | hard upper bound] 2660 ** set at compile-time by a C preprocessor macro called 2661 ** [limits | SQLITE_MAX_<i>NAME</i>]. 2662 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2663 ** ^Attempts to increase a limit above its hard upper bound are 2664 ** silently truncated to the hard upper bound. 2665 ** 2666 ** ^Regardless of whether or not the limit was changed, the 2667 ** [sqlite3_limit()] interface returns the prior value of the limit. 2668 ** ^Hence, to find the current value of a limit without changing it, 2669 ** simply invoke this interface with the third parameter set to -1. 2670 ** 2671 ** Run-time limits are intended for use in applications that manage 2672 ** both their own internal database and also databases that are controlled 2673 ** by untrusted external sources. An example application might be a 2674 ** web browser that has its own databases for storing history and 2675 ** separate databases controlled by JavaScript applications downloaded 2676 ** off the Internet. The internal databases can be given the 2677 ** large, default limits. Databases managed by external sources can 2678 ** be given much smaller limits designed to prevent a denial of service 2679 ** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2680 ** interface to further control untrusted SQL. The size of the database 2681 ** created by an untrusted script can be contained using the 2682 ** [max_page_count] [PRAGMA]. 2683 ** 2684 ** New run-time limit categories may be added in future releases. 2685 */ 2686 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal); 2687 2688 /* 2689 ** CAPI3REF: Run-Time Limit Categories 2690 ** KEYWORDS: {limit category} {*limit categories} 2691 ** 2692 ** These constants define various performance limits 2693 ** that can be lowered at run-time using [sqlite3_limit()]. 2694 ** The synopsis of the meanings of the various limits is shown below. 2695 ** Additional information is available at [limits | Limits in SQLite]. 2696 ** 2697 ** <dl> 2698 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2699 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 2700 ** 2701 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2702 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2703 ** 2704 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2705 ** <dd>The maximum number of columns in a table definition or in the 2706 ** result set of a [SELECT] or the maximum number of columns in an index 2707 ** or in an ORDER BY or GROUP BY clause.</dd>)^ 2708 ** 2709 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2710 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2711 ** 2712 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2713 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2714 ** 2715 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2716 ** <dd>The maximum number of instructions in a virtual machine program 2717 ** used to implement an SQL statement. This limit is not currently 2718 ** enforced, though that might be added in some future release of 2719 ** SQLite.</dd>)^ 2720 ** 2721 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2722 ** <dd>The maximum number of arguments on a function.</dd>)^ 2723 ** 2724 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2725 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2726 ** 2727 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 2728 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2729 ** <dd>The maximum length of the pattern argument to the [LIKE] or 2730 ** [GLOB] operators.</dd>)^ 2731 ** 2732 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 2733 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2734 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 2735 ** 2736 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2737 ** <dd>The maximum depth of recursion for triggers.</dd>)^ 2738 ** </dl> 2739 */ 2740 #define SQLITE_LIMIT_LENGTH 0 2741 #define SQLITE_LIMIT_SQL_LENGTH 1 2742 #define SQLITE_LIMIT_COLUMN 2 2743 #define SQLITE_LIMIT_EXPR_DEPTH 3 2744 #define SQLITE_LIMIT_COMPOUND_SELECT 4 2745 #define SQLITE_LIMIT_VDBE_OP 5 2746 #define SQLITE_LIMIT_FUNCTION_ARG 6 2747 #define SQLITE_LIMIT_ATTACHED 7 2748 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2749 #define SQLITE_LIMIT_VARIABLE_NUMBER 9 2750 #define SQLITE_LIMIT_TRIGGER_DEPTH 10 2751 2752 /* 2753 ** CAPI3REF: Compiling An SQL Statement 2754 ** KEYWORDS: {SQL statement compiler} 2755 ** 2756 ** To execute an SQL query, it must first be compiled into a byte-code 2757 ** program using one of these routines. 2758 ** 2759 ** The first argument, "db", is a [database connection] obtained from a 2760 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2761 ** [sqlite3_open16()]. The database connection must not have been closed. 2762 ** 2763 ** The second argument, "zSql", is the statement to be compiled, encoded 2764 ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2765 ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2766 ** use UTF-16. 2767 ** 2768 ** ^If the nByte argument is less than zero, then zSql is read up to the 2769 ** first zero terminator. ^If nByte is non-negative, then it is the maximum 2770 ** number of bytes read from zSql. ^When nByte is non-negative, the 2771 ** zSql string ends at either the first '\000' or '\u0000' character or 2772 ** the nByte-th byte, whichever comes first. If the caller knows 2773 ** that the supplied string is nul-terminated, then there is a small 2774 ** performance advantage to be gained by passing an nByte parameter that 2775 ** is equal to the number of bytes in the input string <i>including</i> 2776 ** the nul-terminator bytes. 2777 ** 2778 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte 2779 ** past the end of the first SQL statement in zSql. These routines only 2780 ** compile the first statement in zSql, so *pzTail is left pointing to 2781 ** what remains uncompiled. 2782 ** 2783 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 2784 ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 2785 ** to NULL. ^If the input text contains no SQL (if the input is an empty 2786 ** string or a comment) then *ppStmt is set to NULL. 2787 ** The calling procedure is responsible for deleting the compiled 2788 ** SQL statement using [sqlite3_finalize()] after it has finished with it. 2789 ** ppStmt may not be NULL. 2790 ** 2791 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 2792 ** otherwise an [error code] is returned. 2793 ** 2794 ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2795 ** recommended for all new programs. The two older interfaces are retained 2796 ** for backwards compatibility, but their use is discouraged. 2797 ** ^In the "v2" interfaces, the prepared statement 2798 ** that is returned (the [sqlite3_stmt] object) contains a copy of the 2799 ** original SQL text. This causes the [sqlite3_step()] interface to 2800 ** behave differently in three ways: 2801 ** 2802 ** <ol> 2803 ** <li> 2804 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2805 ** always used to do, [sqlite3_step()] will automatically recompile the SQL 2806 ** statement and try to run it again. 2807 ** </li> 2808 ** 2809 ** <li> 2810 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed 2811 ** [error codes] or [extended error codes]. ^The legacy behavior was that 2812 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2813 ** and the application would have to make a second call to [sqlite3_reset()] 2814 ** in order to find the underlying cause of the problem. With the "v2" prepare 2815 ** interfaces, the underlying reason for the error is returned immediately. 2816 ** </li> 2817 ** 2818 ** <li> 2819 ** ^If the specific value bound to [parameter | host parameter] in the 2820 ** WHERE clause might influence the choice of query plan for a statement, 2821 ** then the statement will be automatically recompiled, as if there had been 2822 ** a schema change, on the first [sqlite3_step()] call following any change 2823 ** to the [sqlite3_bind_text | bindings] of that [parameter]. 2824 ** ^The specific value of WHERE-clause [parameter] might influence the 2825 ** choice of query plan if the parameter is the left-hand side of a [LIKE] 2826 ** or [GLOB] operator or if the parameter is compared to an indexed column 2827 ** and the [SQLITE_ENABLE_STAT2] compile-time option is enabled. 2828 ** the 2829 ** </li> 2830 ** </ol> 2831 */ 2832 SQLITE_API int sqlite3_prepare( 2833 sqlite3 *db, /* Database handle */ 2834 const char *zSql, /* SQL statement, UTF-8 encoded */ 2835 int nByte, /* Maximum length of zSql in bytes. */ 2836 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2837 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2838 ); 2839 SQLITE_API int sqlite3_prepare_v2( 2840 sqlite3 *db, /* Database handle */ 2841 const char *zSql, /* SQL statement, UTF-8 encoded */ 2842 int nByte, /* Maximum length of zSql in bytes. */ 2843 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2844 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2845 ); 2846 SQLITE_API int sqlite3_prepare16( 2847 sqlite3 *db, /* Database handle */ 2848 const void *zSql, /* SQL statement, UTF-16 encoded */ 2849 int nByte, /* Maximum length of zSql in bytes. */ 2850 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2851 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2852 ); 2853 SQLITE_API int sqlite3_prepare16_v2( 2854 sqlite3 *db, /* Database handle */ 2855 const void *zSql, /* SQL statement, UTF-16 encoded */ 2856 int nByte, /* Maximum length of zSql in bytes. */ 2857 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2858 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2859 ); 2860 2861 /* 2862 ** CAPI3REF: Retrieving Statement SQL 2863 ** 2864 ** ^This interface can be used to retrieve a saved copy of the original 2865 ** SQL text used to create a [prepared statement] if that statement was 2866 ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2867 */ 2868 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt); 2869 2870 /* 2871 ** CAPI3REF: Determine If An SQL Statement Writes The Database 2872 ** 2873 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 2874 ** and only if the [prepared statement] X makes no direct changes to 2875 ** the content of the database file. 2876 ** 2877 ** Note that [application-defined SQL functions] or 2878 ** [virtual tables] might change the database indirectly as a side effect. 2879 ** ^(For example, if an application defines a function "eval()" that 2880 ** calls [sqlite3_exec()], then the following SQL statement would 2881 ** change the database file through side-effects: 2882 ** 2883 ** <blockquote><pre> 2884 ** SELECT eval('DELETE FROM t1') FROM t2; 2885 ** </pre></blockquote> 2886 ** 2887 ** But because the [SELECT] statement does not change the database file 2888 ** directly, sqlite3_stmt_readonly() would still return true.)^ 2889 ** 2890 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 2891 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 2892 ** since the statements themselves do not actually modify the database but 2893 ** rather they control the timing of when other statements modify the 2894 ** database. ^The [ATTACH] and [DETACH] statements also cause 2895 ** sqlite3_stmt_readonly() to return true since, while those statements 2896 ** change the configuration of a database connection, they do not make 2897 ** changes to the content of the database files on disk. 2898 */ 2899 SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 2900 2901 /* 2902 ** CAPI3REF: Dynamically Typed Value Object 2903 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 2904 ** 2905 ** SQLite uses the sqlite3_value object to represent all values 2906 ** that can be stored in a database table. SQLite uses dynamic typing 2907 ** for the values it stores. ^Values stored in sqlite3_value objects 2908 ** can be integers, floating point values, strings, BLOBs, or NULL. 2909 ** 2910 ** An sqlite3_value object may be either "protected" or "unprotected". 2911 ** Some interfaces require a protected sqlite3_value. Other interfaces 2912 ** will accept either a protected or an unprotected sqlite3_value. 2913 ** Every interface that accepts sqlite3_value arguments specifies 2914 ** whether or not it requires a protected sqlite3_value. 2915 ** 2916 ** The terms "protected" and "unprotected" refer to whether or not 2917 ** a mutex is held. An internal mutex is held for a protected 2918 ** sqlite3_value object but no mutex is held for an unprotected 2919 ** sqlite3_value object. If SQLite is compiled to be single-threaded 2920 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 2921 ** or if SQLite is run in one of reduced mutex modes 2922 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 2923 ** then there is no distinction between protected and unprotected 2924 ** sqlite3_value objects and they can be used interchangeably. However, 2925 ** for maximum code portability it is recommended that applications 2926 ** still make the distinction between protected and unprotected 2927 ** sqlite3_value objects even when not strictly required. 2928 ** 2929 ** ^The sqlite3_value objects that are passed as parameters into the 2930 ** implementation of [application-defined SQL functions] are protected. 2931 ** ^The sqlite3_value object returned by 2932 ** [sqlite3_column_value()] is unprotected. 2933 ** Unprotected sqlite3_value objects may only be used with 2934 ** [sqlite3_result_value()] and [sqlite3_bind_value()]. 2935 ** The [sqlite3_value_blob | sqlite3_value_type()] family of 2936 ** interfaces require protected sqlite3_value objects. 2937 */ 2938 typedef struct Mem sqlite3_value; 2939 2940 /* 2941 ** CAPI3REF: SQL Function Context Object 2942 ** 2943 ** The context in which an SQL function executes is stored in an 2944 ** sqlite3_context object. ^A pointer to an sqlite3_context object 2945 ** is always first parameter to [application-defined SQL functions]. 2946 ** The application-defined SQL function implementation will pass this 2947 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 2948 ** [sqlite3_aggregate_context()], [sqlite3_user_data()], 2949 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 2950 ** and/or [sqlite3_set_auxdata()]. 2951 */ 2952 typedef struct sqlite3_context sqlite3_context; 2953 2954 /* 2955 ** CAPI3REF: Binding Values To Prepared Statements 2956 ** KEYWORDS: {host parameter} {host parameters} {host parameter name} 2957 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 2958 ** 2959 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 2960 ** literals may be replaced by a [parameter] that matches one of following 2961 ** templates: 2962 ** 2963 ** <ul> 2964 ** <li> ? 2965 ** <li> ?NNN 2966 ** <li> :VVV 2967 ** <li> @VVV 2968 ** <li> $VVV 2969 ** </ul> 2970 ** 2971 ** In the templates above, NNN represents an integer literal, 2972 ** and VVV represents an alphanumeric identifier.)^ ^The values of these 2973 ** parameters (also called "host parameter names" or "SQL parameters") 2974 ** can be set using the sqlite3_bind_*() routines defined here. 2975 ** 2976 ** ^The first argument to the sqlite3_bind_*() routines is always 2977 ** a pointer to the [sqlite3_stmt] object returned from 2978 ** [sqlite3_prepare_v2()] or its variants. 2979 ** 2980 ** ^The second argument is the index of the SQL parameter to be set. 2981 ** ^The leftmost SQL parameter has an index of 1. ^When the same named 2982 ** SQL parameter is used more than once, second and subsequent 2983 ** occurrences have the same index as the first occurrence. 2984 ** ^The index for named parameters can be looked up using the 2985 ** [sqlite3_bind_parameter_index()] API if desired. ^The index 2986 ** for "?NNN" parameters is the value of NNN. 2987 ** ^The NNN value must be between 1 and the [sqlite3_limit()] 2988 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 2989 ** 2990 ** ^The third argument is the value to bind to the parameter. 2991 ** 2992 ** ^(In those routines that have a fourth argument, its value is the 2993 ** number of bytes in the parameter. To be clear: the value is the 2994 ** number of <u>bytes</u> in the value, not the number of characters.)^ 2995 ** ^If the fourth parameter is negative, the length of the string is 2996 ** the number of bytes up to the first zero terminator. 2997 ** 2998 ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 2999 ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 3000 ** string after SQLite has finished with it. ^The destructor is called 3001 ** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(), 3002 ** sqlite3_bind_text(), or sqlite3_bind_text16() fails. 3003 ** ^If the fifth argument is 3004 ** the special value [SQLITE_STATIC], then SQLite assumes that the 3005 ** information is in static, unmanaged space and does not need to be freed. 3006 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3007 ** SQLite makes its own private copy of the data immediately, before 3008 ** the sqlite3_bind_*() routine returns. 3009 ** 3010 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3011 ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3012 ** (just an integer to hold its size) while it is being processed. 3013 ** Zeroblobs are intended to serve as placeholders for BLOBs whose 3014 ** content is later written using 3015 ** [sqlite3_blob_open | incremental BLOB I/O] routines. 3016 ** ^A negative value for the zeroblob results in a zero-length BLOB. 3017 ** 3018 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3019 ** for the [prepared statement] or with a prepared statement for which 3020 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3021 ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3022 ** routine is passed a [prepared statement] that has been finalized, the 3023 ** result is undefined and probably harmful. 3024 ** 3025 ** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3026 ** ^Unbound parameters are interpreted as NULL. 3027 ** 3028 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3029 ** [error code] if anything goes wrong. 3030 ** ^[SQLITE_RANGE] is returned if the parameter 3031 ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3032 ** 3033 ** See also: [sqlite3_bind_parameter_count()], 3034 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3035 */ 3036 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3037 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double); 3038 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int); 3039 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3040 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int); 3041 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 3042 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3043 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3044 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3045 3046 /* 3047 ** CAPI3REF: Number Of SQL Parameters 3048 ** 3049 ** ^This routine can be used to find the number of [SQL parameters] 3050 ** in a [prepared statement]. SQL parameters are tokens of the 3051 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3052 ** placeholders for values that are [sqlite3_bind_blob | bound] 3053 ** to the parameters at a later time. 3054 ** 3055 ** ^(This routine actually returns the index of the largest (rightmost) 3056 ** parameter. For all forms except ?NNN, this will correspond to the 3057 ** number of unique parameters. If parameters of the ?NNN form are used, 3058 ** there may be gaps in the list.)^ 3059 ** 3060 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 3061 ** [sqlite3_bind_parameter_name()], and 3062 ** [sqlite3_bind_parameter_index()]. 3063 */ 3064 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*); 3065 3066 /* 3067 ** CAPI3REF: Name Of A Host Parameter 3068 ** 3069 ** ^The sqlite3_bind_parameter_name(P,N) interface returns 3070 ** the name of the N-th [SQL parameter] in the [prepared statement] P. 3071 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3072 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3073 ** respectively. 3074 ** In other words, the initial ":" or "$" or "@" or "?" 3075 ** is included as part of the name.)^ 3076 ** ^Parameters of the form "?" without a following integer have no name 3077 ** and are referred to as "nameless" or "anonymous parameters". 3078 ** 3079 ** ^The first host parameter has an index of 1, not 0. 3080 ** 3081 ** ^If the value N is out of range or if the N-th parameter is 3082 ** nameless, then NULL is returned. ^The returned string is 3083 ** always in UTF-8 encoding even if the named parameter was 3084 ** originally specified as UTF-16 in [sqlite3_prepare16()] or 3085 ** [sqlite3_prepare16_v2()]. 3086 ** 3087 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 3088 ** [sqlite3_bind_parameter_count()], and 3089 ** [sqlite3_bind_parameter_index()]. 3090 */ 3091 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3092 3093 /* 3094 ** CAPI3REF: Index Of A Parameter With A Given Name 3095 ** 3096 ** ^Return the index of an SQL parameter given its name. ^The 3097 ** index value returned is suitable for use as the second 3098 ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3099 ** is returned if no matching parameter is found. ^The parameter 3100 ** name must be given in UTF-8 even if the original statement 3101 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3102 ** 3103 ** See also: [sqlite3_bind_blob|sqlite3_bind()], 3104 ** [sqlite3_bind_parameter_count()], and 3105 ** [sqlite3_bind_parameter_index()]. 3106 */ 3107 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3108 3109 /* 3110 ** CAPI3REF: Reset All Bindings On A Prepared Statement 3111 ** 3112 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3113 ** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3114 ** ^Use this routine to reset all host parameters to NULL. 3115 */ 3116 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*); 3117 3118 /* 3119 ** CAPI3REF: Number Of Columns In A Result Set 3120 ** 3121 ** ^Return the number of columns in the result set returned by the 3122 ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3123 ** statement that does not return data (for example an [UPDATE]). 3124 ** 3125 ** See also: [sqlite3_data_count()] 3126 */ 3127 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt); 3128 3129 /* 3130 ** CAPI3REF: Column Names In A Result Set 3131 ** 3132 ** ^These routines return the name assigned to a particular column 3133 ** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3134 ** interface returns a pointer to a zero-terminated UTF-8 string 3135 ** and sqlite3_column_name16() returns a pointer to a zero-terminated 3136 ** UTF-16 string. ^The first parameter is the [prepared statement] 3137 ** that implements the [SELECT] statement. ^The second parameter is the 3138 ** column number. ^The leftmost column is number 0. 3139 ** 3140 ** ^The returned string pointer is valid until either the [prepared statement] 3141 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3142 ** reprepared by the first call to [sqlite3_step()] for a particular run 3143 ** or until the next call to 3144 ** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3145 ** 3146 ** ^If sqlite3_malloc() fails during the processing of either routine 3147 ** (for example during a conversion from UTF-8 to UTF-16) then a 3148 ** NULL pointer is returned. 3149 ** 3150 ** ^The name of a result column is the value of the "AS" clause for 3151 ** that column, if there is an AS clause. If there is no AS clause 3152 ** then the name of the column is unspecified and may change from 3153 ** one release of SQLite to the next. 3154 */ 3155 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N); 3156 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3157 3158 /* 3159 ** CAPI3REF: Source Of Data In A Query Result 3160 ** 3161 ** ^These routines provide a means to determine the database, table, and 3162 ** table column that is the origin of a particular result column in 3163 ** [SELECT] statement. 3164 ** ^The name of the database or table or column can be returned as 3165 ** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3166 ** the database name, the _table_ routines return the table name, and 3167 ** the origin_ routines return the column name. 3168 ** ^The returned string is valid until the [prepared statement] is destroyed 3169 ** using [sqlite3_finalize()] or until the statement is automatically 3170 ** reprepared by the first call to [sqlite3_step()] for a particular run 3171 ** or until the same information is requested 3172 ** again in a different encoding. 3173 ** 3174 ** ^The names returned are the original un-aliased names of the 3175 ** database, table, and column. 3176 ** 3177 ** ^The first argument to these interfaces is a [prepared statement]. 3178 ** ^These functions return information about the Nth result column returned by 3179 ** the statement, where N is the second function argument. 3180 ** ^The left-most column is column 0 for these routines. 3181 ** 3182 ** ^If the Nth column returned by the statement is an expression or 3183 ** subquery and is not a column value, then all of these functions return 3184 ** NULL. ^These routine might also return NULL if a memory allocation error 3185 ** occurs. ^Otherwise, they return the name of the attached database, table, 3186 ** or column that query result column was extracted from. 3187 ** 3188 ** ^As with all other SQLite APIs, those whose names end with "16" return 3189 ** UTF-16 encoded strings and the other functions return UTF-8. 3190 ** 3191 ** ^These APIs are only available if the library was compiled with the 3192 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3193 ** 3194 ** If two or more threads call one or more of these routines against the same 3195 ** prepared statement and column at the same time then the results are 3196 ** undefined. 3197 ** 3198 ** If two or more threads call one or more 3199 ** [sqlite3_column_database_name | column metadata interfaces] 3200 ** for the same [prepared statement] and result column 3201 ** at the same time then the results are undefined. 3202 */ 3203 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3204 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3205 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3206 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3207 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3208 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3209 3210 /* 3211 ** CAPI3REF: Declared Datatype Of A Query Result 3212 ** 3213 ** ^(The first parameter is a [prepared statement]. 3214 ** If this statement is a [SELECT] statement and the Nth column of the 3215 ** returned result set of that [SELECT] is a table column (not an 3216 ** expression or subquery) then the declared type of the table 3217 ** column is returned.)^ ^If the Nth column of the result set is an 3218 ** expression or subquery, then a NULL pointer is returned. 3219 ** ^The returned string is always UTF-8 encoded. 3220 ** 3221 ** ^(For example, given the database schema: 3222 ** 3223 ** CREATE TABLE t1(c1 VARIANT); 3224 ** 3225 ** and the following statement to be compiled: 3226 ** 3227 ** SELECT c1 + 1, c1 FROM t1; 3228 ** 3229 ** this routine would return the string "VARIANT" for the second result 3230 ** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3231 ** 3232 ** ^SQLite uses dynamic run-time typing. ^So just because a column 3233 ** is declared to contain a particular type does not mean that the 3234 ** data stored in that column is of the declared type. SQLite is 3235 ** strongly typed, but the typing is dynamic not static. ^Type 3236 ** is associated with individual values, not with the containers 3237 ** used to hold those values. 3238 */ 3239 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3240 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3241 3242 /* 3243 ** CAPI3REF: Evaluate An SQL Statement 3244 ** 3245 ** After a [prepared statement] has been prepared using either 3246 ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3247 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3248 ** must be called one or more times to evaluate the statement. 3249 ** 3250 ** The details of the behavior of the sqlite3_step() interface depend 3251 ** on whether the statement was prepared using the newer "v2" interface 3252 ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3253 ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3254 ** new "v2" interface is recommended for new applications but the legacy 3255 ** interface will continue to be supported. 3256 ** 3257 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3258 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3259 ** ^With the "v2" interface, any of the other [result codes] or 3260 ** [extended result codes] might be returned as well. 3261 ** 3262 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3263 ** database locks it needs to do its job. ^If the statement is a [COMMIT] 3264 ** or occurs outside of an explicit transaction, then you can retry the 3265 ** statement. If the statement is not a [COMMIT] and occurs within an 3266 ** explicit transaction then you should rollback the transaction before 3267 ** continuing. 3268 ** 3269 ** ^[SQLITE_DONE] means that the statement has finished executing 3270 ** successfully. sqlite3_step() should not be called again on this virtual 3271 ** machine without first calling [sqlite3_reset()] to reset the virtual 3272 ** machine back to its initial state. 3273 ** 3274 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3275 ** is returned each time a new row of data is ready for processing by the 3276 ** caller. The values may be accessed using the [column access functions]. 3277 ** sqlite3_step() is called again to retrieve the next row of data. 3278 ** 3279 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3280 ** violation) has occurred. sqlite3_step() should not be called again on 3281 ** the VM. More information may be found by calling [sqlite3_errmsg()]. 3282 ** ^With the legacy interface, a more specific error code (for example, 3283 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3284 ** can be obtained by calling [sqlite3_reset()] on the 3285 ** [prepared statement]. ^In the "v2" interface, 3286 ** the more specific error code is returned directly by sqlite3_step(). 3287 ** 3288 ** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3289 ** Perhaps it was called on a [prepared statement] that has 3290 ** already been [sqlite3_finalize | finalized] or on one that had 3291 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3292 ** be the case that the same database connection is being used by two or 3293 ** more threads at the same moment in time. 3294 ** 3295 ** For all versions of SQLite up to and including 3.6.23.1, a call to 3296 ** [sqlite3_reset()] was required after sqlite3_step() returned anything 3297 ** other than [SQLITE_ROW] before any subsequent invocation of 3298 ** sqlite3_step(). Failure to reset the prepared statement using 3299 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3300 ** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3301 ** calling [sqlite3_reset()] automatically in this circumstance rather 3302 ** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3303 ** break because any application that ever receives an SQLITE_MISUSE error 3304 ** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3305 ** can be used to restore the legacy behavior. 3306 ** 3307 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3308 ** API always returns a generic error code, [SQLITE_ERROR], following any 3309 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3310 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3311 ** specific [error codes] that better describes the error. 3312 ** We admit that this is a goofy design. The problem has been fixed 3313 ** with the "v2" interface. If you prepare all of your SQL statements 3314 ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3315 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3316 ** then the more specific [error codes] are returned directly 3317 ** by sqlite3_step(). The use of the "v2" interface is recommended. 3318 */ 3319 SQLITE_API int sqlite3_step(sqlite3_stmt*); 3320 3321 /* 3322 ** CAPI3REF: Number of columns in a result set 3323 ** 3324 ** ^The sqlite3_data_count(P) interface returns the number of columns in the 3325 ** current row of the result set of [prepared statement] P. 3326 ** ^If prepared statement P does not have results ready to return 3327 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3328 ** interfaces) then sqlite3_data_count(P) returns 0. 3329 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3330 ** 3331 ** See also: [sqlite3_column_count()] 3332 */ 3333 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt); 3334 3335 /* 3336 ** CAPI3REF: Fundamental Datatypes 3337 ** KEYWORDS: SQLITE_TEXT 3338 ** 3339 ** ^(Every value in SQLite has one of five fundamental datatypes: 3340 ** 3341 ** <ul> 3342 ** <li> 64-bit signed integer 3343 ** <li> 64-bit IEEE floating point number 3344 ** <li> string 3345 ** <li> BLOB 3346 ** <li> NULL 3347 ** </ul>)^ 3348 ** 3349 ** These constants are codes for each of those types. 3350 ** 3351 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3352 ** for a completely different meaning. Software that links against both 3353 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3354 ** SQLITE_TEXT. 3355 */ 3356 #define SQLITE_INTEGER 1 3357 #define SQLITE_FLOAT 2 3358 #define SQLITE_BLOB 4 3359 #define SQLITE_NULL 5 3360 #ifdef SQLITE_TEXT 3361 # undef SQLITE_TEXT 3362 #else 3363 # define SQLITE_TEXT 3 3364 #endif 3365 #define SQLITE3_TEXT 3 3366 3367 /* 3368 ** CAPI3REF: Result Values From A Query 3369 ** KEYWORDS: {column access functions} 3370 ** 3371 ** These routines form the "result set" interface. 3372 ** 3373 ** ^These routines return information about a single column of the current 3374 ** result row of a query. ^In every case the first argument is a pointer 3375 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3376 ** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3377 ** and the second argument is the index of the column for which information 3378 ** should be returned. ^The leftmost column of the result set has the index 0. 3379 ** ^The number of columns in the result can be determined using 3380 ** [sqlite3_column_count()]. 3381 ** 3382 ** If the SQL statement does not currently point to a valid row, or if the 3383 ** column index is out of range, the result is undefined. 3384 ** These routines may only be called when the most recent call to 3385 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3386 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3387 ** If any of these routines are called after [sqlite3_reset()] or 3388 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3389 ** something other than [SQLITE_ROW], the results are undefined. 3390 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3391 ** are called from a different thread while any of these routines 3392 ** are pending, then the results are undefined. 3393 ** 3394 ** ^The sqlite3_column_type() routine returns the 3395 ** [SQLITE_INTEGER | datatype code] for the initial data type 3396 ** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3397 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3398 ** returned by sqlite3_column_type() is only meaningful if no type 3399 ** conversions have occurred as described below. After a type conversion, 3400 ** the value returned by sqlite3_column_type() is undefined. Future 3401 ** versions of SQLite may change the behavior of sqlite3_column_type() 3402 ** following a type conversion. 3403 ** 3404 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3405 ** routine returns the number of bytes in that BLOB or string. 3406 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3407 ** the string to UTF-8 and then returns the number of bytes. 3408 ** ^If the result is a numeric value then sqlite3_column_bytes() uses 3409 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3410 ** the number of bytes in that string. 3411 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3412 ** 3413 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3414 ** routine returns the number of bytes in that BLOB or string. 3415 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3416 ** the string to UTF-16 and then returns the number of bytes. 3417 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3418 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3419 ** the number of bytes in that string. 3420 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3421 ** 3422 ** ^The values returned by [sqlite3_column_bytes()] and 3423 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3424 ** of the string. ^For clarity: the values returned by 3425 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3426 ** bytes in the string, not the number of characters. 3427 ** 3428 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3429 ** even empty strings, are always zero terminated. ^The return 3430 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3431 ** 3432 ** ^The object returned by [sqlite3_column_value()] is an 3433 ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3434 ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3435 ** If the [unprotected sqlite3_value] object returned by 3436 ** [sqlite3_column_value()] is used in any other way, including calls 3437 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3438 ** or [sqlite3_value_bytes()], then the behavior is undefined. 3439 ** 3440 ** These routines attempt to convert the value where appropriate. ^For 3441 ** example, if the internal representation is FLOAT and a text result 3442 ** is requested, [sqlite3_snprintf()] is used internally to perform the 3443 ** conversion automatically. ^(The following table details the conversions 3444 ** that are applied: 3445 ** 3446 ** <blockquote> 3447 ** <table border="1"> 3448 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3449 ** 3450 ** <tr><td> NULL <td> INTEGER <td> Result is 0 3451 ** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3452 ** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3453 ** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3454 ** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3455 ** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3456 ** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3457 ** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3458 ** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3459 ** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3460 ** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3461 ** <tr><td> TEXT <td> FLOAT <td> Use atof() 3462 ** <tr><td> TEXT <td> BLOB <td> No change 3463 ** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3464 ** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3465 ** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3466 ** </table> 3467 ** </blockquote>)^ 3468 ** 3469 ** The table above makes reference to standard C library functions atoi() 3470 ** and atof(). SQLite does not really use these functions. It has its 3471 ** own equivalent internal routines. The atoi() and atof() names are 3472 ** used in the table for brevity and because they are familiar to most 3473 ** C programmers. 3474 ** 3475 ** Note that when type conversions occur, pointers returned by prior 3476 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3477 ** sqlite3_column_text16() may be invalidated. 3478 ** Type conversions and pointer invalidations might occur 3479 ** in the following cases: 3480 ** 3481 ** <ul> 3482 ** <li> The initial content is a BLOB and sqlite3_column_text() or 3483 ** sqlite3_column_text16() is called. A zero-terminator might 3484 ** need to be added to the string.</li> 3485 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3486 ** sqlite3_column_text16() is called. The content must be converted 3487 ** to UTF-16.</li> 3488 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3489 ** sqlite3_column_text() is called. The content must be converted 3490 ** to UTF-8.</li> 3491 ** </ul> 3492 ** 3493 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3494 ** not invalidate a prior pointer, though of course the content of the buffer 3495 ** that the prior pointer references will have been modified. Other kinds 3496 ** of conversion are done in place when it is possible, but sometimes they 3497 ** are not possible and in those cases prior pointers are invalidated. 3498 ** 3499 ** The safest and easiest to remember policy is to invoke these routines 3500 ** in one of the following ways: 3501 ** 3502 ** <ul> 3503 ** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3504 ** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3505 ** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3506 ** </ul> 3507 ** 3508 ** In other words, you should call sqlite3_column_text(), 3509 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3510 ** into the desired format, then invoke sqlite3_column_bytes() or 3511 ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3512 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3513 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3514 ** with calls to sqlite3_column_bytes(). 3515 ** 3516 ** ^The pointers returned are valid until a type conversion occurs as 3517 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3518 ** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3519 ** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3520 ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3521 ** [sqlite3_free()]. 3522 ** 3523 ** ^(If a memory allocation error occurs during the evaluation of any 3524 ** of these routines, a default value is returned. The default value 3525 ** is either the integer 0, the floating point number 0.0, or a NULL 3526 ** pointer. Subsequent calls to [sqlite3_errcode()] will return 3527 ** [SQLITE_NOMEM].)^ 3528 */ 3529 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3530 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3531 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3532 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol); 3533 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol); 3534 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3535 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3536 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3537 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol); 3538 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3539 3540 /* 3541 ** CAPI3REF: Destroy A Prepared Statement Object 3542 ** 3543 ** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3544 ** ^If the most recent evaluation of the statement encountered no errors 3545 ** or if the statement is never been evaluated, then sqlite3_finalize() returns 3546 ** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 3547 ** sqlite3_finalize(S) returns the appropriate [error code] or 3548 ** [extended error code]. 3549 ** 3550 ** ^The sqlite3_finalize(S) routine can be called at any point during 3551 ** the life cycle of [prepared statement] S: 3552 ** before statement S is ever evaluated, after 3553 ** one or more calls to [sqlite3_reset()], or after any call 3554 ** to [sqlite3_step()] regardless of whether or not the statement has 3555 ** completed execution. 3556 ** 3557 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 3558 ** 3559 ** The application must finalize every [prepared statement] in order to avoid 3560 ** resource leaks. It is a grievous error for the application to try to use 3561 ** a prepared statement after it has been finalized. Any use of a prepared 3562 ** statement after it has been finalized can result in undefined and 3563 ** undesirable behavior such as segfaults and heap corruption. 3564 */ 3565 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt); 3566 3567 /* 3568 ** CAPI3REF: Reset A Prepared Statement Object 3569 ** 3570 ** The sqlite3_reset() function is called to reset a [prepared statement] 3571 ** object back to its initial state, ready to be re-executed. 3572 ** ^Any SQL statement variables that had values bound to them using 3573 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3574 ** Use [sqlite3_clear_bindings()] to reset the bindings. 3575 ** 3576 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3577 ** back to the beginning of its program. 3578 ** 3579 ** ^If the most recent call to [sqlite3_step(S)] for the 3580 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3581 ** or if [sqlite3_step(S)] has never before been called on S, 3582 ** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3583 ** 3584 ** ^If the most recent call to [sqlite3_step(S)] for the 3585 ** [prepared statement] S indicated an error, then 3586 ** [sqlite3_reset(S)] returns an appropriate [error code]. 3587 ** 3588 ** ^The [sqlite3_reset(S)] interface does not change the values 3589 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3590 */ 3591 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt); 3592 3593 /* 3594 ** CAPI3REF: Create Or Redefine SQL Functions 3595 ** KEYWORDS: {function creation routines} 3596 ** KEYWORDS: {application-defined SQL function} 3597 ** KEYWORDS: {application-defined SQL functions} 3598 ** 3599 ** ^These functions (collectively known as "function creation routines") 3600 ** are used to add SQL functions or aggregates or to redefine the behavior 3601 ** of existing SQL functions or aggregates. The only differences between 3602 ** these routines are the text encoding expected for 3603 ** the second parameter (the name of the function being created) 3604 ** and the presence or absence of a destructor callback for 3605 ** the application data pointer. 3606 ** 3607 ** ^The first parameter is the [database connection] to which the SQL 3608 ** function is to be added. ^If an application uses more than one database 3609 ** connection then application-defined SQL functions must be added 3610 ** to each database connection separately. 3611 ** 3612 ** ^The second parameter is the name of the SQL function to be created or 3613 ** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 3614 ** representation, exclusive of the zero-terminator. ^Note that the name 3615 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 3616 ** ^Any attempt to create a function with a longer name 3617 ** will result in [SQLITE_MISUSE] being returned. 3618 ** 3619 ** ^The third parameter (nArg) 3620 ** is the number of arguments that the SQL function or 3621 ** aggregate takes. ^If this parameter is -1, then the SQL function or 3622 ** aggregate may take any number of arguments between 0 and the limit 3623 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3624 ** parameter is less than -1 or greater than 127 then the behavior is 3625 ** undefined. 3626 ** 3627 ** ^The fourth parameter, eTextRep, specifies what 3628 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3629 ** its parameters. Every SQL function implementation must be able to work 3630 ** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3631 ** more efficient with one encoding than another. ^An application may 3632 ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3633 ** times with the same function but with different values of eTextRep. 3634 ** ^When multiple implementations of the same function are available, SQLite 3635 ** will pick the one that involves the least amount of data conversion. 3636 ** If there is only a single implementation which does not care what text 3637 ** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3638 ** 3639 ** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3640 ** function can gain access to this pointer using [sqlite3_user_data()].)^ 3641 ** 3642 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 3643 ** pointers to C-language functions that implement the SQL function or 3644 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3645 ** callback only; NULL pointers must be passed as the xStep and xFinal 3646 ** parameters. ^An aggregate SQL function requires an implementation of xStep 3647 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 3648 ** SQL function or aggregate, pass NULL pointers for all three function 3649 ** callbacks. 3650 ** 3651 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 3652 ** then it is destructor for the application data pointer. 3653 ** The destructor is invoked when the function is deleted, either by being 3654 ** overloaded or when the database connection closes.)^ 3655 ** ^The destructor is also invoked if the call to 3656 ** sqlite3_create_function_v2() fails. 3657 ** ^When the destructor callback of the tenth parameter is invoked, it 3658 ** is passed a single argument which is a copy of the application data 3659 ** pointer which was the fifth parameter to sqlite3_create_function_v2(). 3660 ** 3661 ** ^It is permitted to register multiple implementations of the same 3662 ** functions with the same name but with either differing numbers of 3663 ** arguments or differing preferred text encodings. ^SQLite will use 3664 ** the implementation that most closely matches the way in which the 3665 ** SQL function is used. ^A function implementation with a non-negative 3666 ** nArg parameter is a better match than a function implementation with 3667 ** a negative nArg. ^A function where the preferred text encoding 3668 ** matches the database encoding is a better 3669 ** match than a function where the encoding is different. 3670 ** ^A function where the encoding difference is between UTF16le and UTF16be 3671 ** is a closer match than a function where the encoding difference is 3672 ** between UTF8 and UTF16. 3673 ** 3674 ** ^Built-in functions may be overloaded by new application-defined functions. 3675 ** 3676 ** ^An application-defined function is permitted to call other 3677 ** SQLite interfaces. However, such calls must not 3678 ** close the database connection nor finalize or reset the prepared 3679 ** statement in which the function is running. 3680 */ 3681 SQLITE_API int sqlite3_create_function( 3682 sqlite3 *db, 3683 const char *zFunctionName, 3684 int nArg, 3685 int eTextRep, 3686 void *pApp, 3687 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3688 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3689 void (*xFinal)(sqlite3_context*) 3690 ); 3691 SQLITE_API int sqlite3_create_function16( 3692 sqlite3 *db, 3693 const void *zFunctionName, 3694 int nArg, 3695 int eTextRep, 3696 void *pApp, 3697 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3698 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3699 void (*xFinal)(sqlite3_context*) 3700 ); 3701 SQLITE_API int sqlite3_create_function_v2( 3702 sqlite3 *db, 3703 const char *zFunctionName, 3704 int nArg, 3705 int eTextRep, 3706 void *pApp, 3707 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3708 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3709 void (*xFinal)(sqlite3_context*), 3710 void(*xDestroy)(void*) 3711 ); 3712 3713 /* 3714 ** CAPI3REF: Text Encodings 3715 ** 3716 ** These constant define integer codes that represent the various 3717 ** text encodings supported by SQLite. 3718 */ 3719 #define SQLITE_UTF8 1 3720 #define SQLITE_UTF16LE 2 3721 #define SQLITE_UTF16BE 3 3722 #define SQLITE_UTF16 4 /* Use native byte order */ 3723 #define SQLITE_ANY 5 /* sqlite3_create_function only */ 3724 #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3725 3726 /* 3727 ** CAPI3REF: Deprecated Functions 3728 ** DEPRECATED 3729 ** 3730 ** These functions are [deprecated]. In order to maintain 3731 ** backwards compatibility with older code, these functions continue 3732 ** to be supported. However, new applications should avoid 3733 ** the use of these functions. To help encourage people to avoid 3734 ** using these functions, we are not going to tell you what they do. 3735 */ 3736 #ifndef SQLITE_OMIT_DEPRECATED 3737 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3738 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3739 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3740 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void); 3741 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3742 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3743 #endif 3744 3745 /* 3746 ** CAPI3REF: Obtaining SQL Function Parameter Values 3747 ** 3748 ** The C-language implementation of SQL functions and aggregates uses 3749 ** this set of interface routines to access the parameter values on 3750 ** the function or aggregate. 3751 ** 3752 ** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3753 ** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3754 ** define callbacks that implement the SQL functions and aggregates. 3755 ** The 3rd parameter to these callbacks is an array of pointers to 3756 ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3757 ** each parameter to the SQL function. These routines are used to 3758 ** extract values from the [sqlite3_value] objects. 3759 ** 3760 ** These routines work only with [protected sqlite3_value] objects. 3761 ** Any attempt to use these routines on an [unprotected sqlite3_value] 3762 ** object results in undefined behavior. 3763 ** 3764 ** ^These routines work just like the corresponding [column access functions] 3765 ** except that these routines take a single [protected sqlite3_value] object 3766 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3767 ** 3768 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string 3769 ** in the native byte-order of the host machine. ^The 3770 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3771 ** extract UTF-16 strings as big-endian and little-endian respectively. 3772 ** 3773 ** ^(The sqlite3_value_numeric_type() interface attempts to apply 3774 ** numeric affinity to the value. This means that an attempt is 3775 ** made to convert the value to an integer or floating point. If 3776 ** such a conversion is possible without loss of information (in other 3777 ** words, if the value is a string that looks like a number) 3778 ** then the conversion is performed. Otherwise no conversion occurs. 3779 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 3780 ** 3781 ** Please pay particular attention to the fact that the pointer returned 3782 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3783 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3784 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3785 ** or [sqlite3_value_text16()]. 3786 ** 3787 ** These routines must be called from the same thread as 3788 ** the SQL function that supplied the [sqlite3_value*] parameters. 3789 */ 3790 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*); 3791 SQLITE_API int sqlite3_value_bytes(sqlite3_value*); 3792 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*); 3793 SQLITE_API double sqlite3_value_double(sqlite3_value*); 3794 SQLITE_API int sqlite3_value_int(sqlite3_value*); 3795 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3796 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*); 3797 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*); 3798 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*); 3799 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*); 3800 SQLITE_API int sqlite3_value_type(sqlite3_value*); 3801 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*); 3802 3803 /* 3804 ** CAPI3REF: Obtain Aggregate Function Context 3805 ** 3806 ** Implementations of aggregate SQL functions use this 3807 ** routine to allocate memory for storing their state. 3808 ** 3809 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called 3810 ** for a particular aggregate function, SQLite 3811 ** allocates N of memory, zeroes out that memory, and returns a pointer 3812 ** to the new memory. ^On second and subsequent calls to 3813 ** sqlite3_aggregate_context() for the same aggregate function instance, 3814 ** the same buffer is returned. Sqlite3_aggregate_context() is normally 3815 ** called once for each invocation of the xStep callback and then one 3816 ** last time when the xFinal callback is invoked. ^(When no rows match 3817 ** an aggregate query, the xStep() callback of the aggregate function 3818 ** implementation is never called and xFinal() is called exactly once. 3819 ** In those cases, sqlite3_aggregate_context() might be called for the 3820 ** first time from within xFinal().)^ 3821 ** 3822 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is 3823 ** less than or equal to zero or if a memory allocate error occurs. 3824 ** 3825 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 3826 ** determined by the N parameter on first successful call. Changing the 3827 ** value of N in subsequent call to sqlite3_aggregate_context() within 3828 ** the same aggregate function instance will not resize the memory 3829 ** allocation.)^ 3830 ** 3831 ** ^SQLite automatically frees the memory allocated by 3832 ** sqlite3_aggregate_context() when the aggregate query concludes. 3833 ** 3834 ** The first parameter must be a copy of the 3835 ** [sqlite3_context | SQL function context] that is the first parameter 3836 ** to the xStep or xFinal callback routine that implements the aggregate 3837 ** function. 3838 ** 3839 ** This routine must be called from the same thread in which 3840 ** the aggregate SQL function is running. 3841 */ 3842 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 3843 3844 /* 3845 ** CAPI3REF: User Data For Functions 3846 ** 3847 ** ^The sqlite3_user_data() interface returns a copy of 3848 ** the pointer that was the pUserData parameter (the 5th parameter) 3849 ** of the [sqlite3_create_function()] 3850 ** and [sqlite3_create_function16()] routines that originally 3851 ** registered the application defined function. 3852 ** 3853 ** This routine must be called from the same thread in which 3854 ** the application-defined function is running. 3855 */ 3856 SQLITE_API void *sqlite3_user_data(sqlite3_context*); 3857 3858 /* 3859 ** CAPI3REF: Database Connection For Functions 3860 ** 3861 ** ^The sqlite3_context_db_handle() interface returns a copy of 3862 ** the pointer to the [database connection] (the 1st parameter) 3863 ** of the [sqlite3_create_function()] 3864 ** and [sqlite3_create_function16()] routines that originally 3865 ** registered the application defined function. 3866 */ 3867 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 3868 3869 /* 3870 ** CAPI3REF: Function Auxiliary Data 3871 ** 3872 ** The following two functions may be used by scalar SQL functions to 3873 ** associate metadata with argument values. If the same value is passed to 3874 ** multiple invocations of the same SQL function during query execution, under 3875 ** some circumstances the associated metadata may be preserved. This may 3876 ** be used, for example, to add a regular-expression matching scalar 3877 ** function. The compiled version of the regular expression is stored as 3878 ** metadata associated with the SQL value passed as the regular expression 3879 ** pattern. The compiled regular expression can be reused on multiple 3880 ** invocations of the same function so that the original pattern string 3881 ** does not need to be recompiled on each invocation. 3882 ** 3883 ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 3884 ** associated by the sqlite3_set_auxdata() function with the Nth argument 3885 ** value to the application-defined function. ^If no metadata has been ever 3886 ** been set for the Nth argument of the function, or if the corresponding 3887 ** function parameter has changed since the meta-data was set, 3888 ** then sqlite3_get_auxdata() returns a NULL pointer. 3889 ** 3890 ** ^The sqlite3_set_auxdata() interface saves the metadata 3891 ** pointed to by its 3rd parameter as the metadata for the N-th 3892 ** argument of the application-defined function. Subsequent 3893 ** calls to sqlite3_get_auxdata() might return this data, if it has 3894 ** not been destroyed. 3895 ** ^If it is not NULL, SQLite will invoke the destructor 3896 ** function given by the 4th parameter to sqlite3_set_auxdata() on 3897 ** the metadata when the corresponding function parameter changes 3898 ** or when the SQL statement completes, whichever comes first. 3899 ** 3900 ** SQLite is free to call the destructor and drop metadata on any 3901 ** parameter of any function at any time. ^The only guarantee is that 3902 ** the destructor will be called before the metadata is dropped. 3903 ** 3904 ** ^(In practice, metadata is preserved between function calls for 3905 ** expressions that are constant at compile time. This includes literal 3906 ** values and [parameters].)^ 3907 ** 3908 ** These routines must be called from the same thread in which 3909 ** the SQL function is running. 3910 */ 3911 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N); 3912 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 3913 3914 3915 /* 3916 ** CAPI3REF: Constants Defining Special Destructor Behavior 3917 ** 3918 ** These are special values for the destructor that is passed in as the 3919 ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 3920 ** argument is SQLITE_STATIC, it means that the content pointer is constant 3921 ** and will never change. It does not need to be destroyed. ^The 3922 ** SQLITE_TRANSIENT value means that the content will likely change in 3923 ** the near future and that SQLite should make its own private copy of 3924 ** the content before returning. 3925 ** 3926 ** The typedef is necessary to work around problems in certain 3927 ** C++ compilers. See ticket #2191. 3928 */ 3929 typedef void (*sqlite3_destructor_type)(void*); 3930 #define SQLITE_STATIC ((sqlite3_destructor_type)0) 3931 #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 3932 3933 /* 3934 ** CAPI3REF: Setting The Result Of An SQL Function 3935 ** 3936 ** These routines are used by the xFunc or xFinal callbacks that 3937 ** implement SQL functions and aggregates. See 3938 ** [sqlite3_create_function()] and [sqlite3_create_function16()] 3939 ** for additional information. 3940 ** 3941 ** These functions work very much like the [parameter binding] family of 3942 ** functions used to bind values to host parameters in prepared statements. 3943 ** Refer to the [SQL parameter] documentation for additional information. 3944 ** 3945 ** ^The sqlite3_result_blob() interface sets the result from 3946 ** an application-defined function to be the BLOB whose content is pointed 3947 ** to by the second parameter and which is N bytes long where N is the 3948 ** third parameter. 3949 ** 3950 ** ^The sqlite3_result_zeroblob() interfaces set the result of 3951 ** the application-defined function to be a BLOB containing all zero 3952 ** bytes and N bytes in size, where N is the value of the 2nd parameter. 3953 ** 3954 ** ^The sqlite3_result_double() interface sets the result from 3955 ** an application-defined function to be a floating point value specified 3956 ** by its 2nd argument. 3957 ** 3958 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions 3959 ** cause the implemented SQL function to throw an exception. 3960 ** ^SQLite uses the string pointed to by the 3961 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 3962 ** as the text of an error message. ^SQLite interprets the error 3963 ** message string from sqlite3_result_error() as UTF-8. ^SQLite 3964 ** interprets the string from sqlite3_result_error16() as UTF-16 in native 3965 ** byte order. ^If the third parameter to sqlite3_result_error() 3966 ** or sqlite3_result_error16() is negative then SQLite takes as the error 3967 ** message all text up through the first zero character. 3968 ** ^If the third parameter to sqlite3_result_error() or 3969 ** sqlite3_result_error16() is non-negative then SQLite takes that many 3970 ** bytes (not characters) from the 2nd parameter as the error message. 3971 ** ^The sqlite3_result_error() and sqlite3_result_error16() 3972 ** routines make a private copy of the error message text before 3973 ** they return. Hence, the calling function can deallocate or 3974 ** modify the text after they return without harm. 3975 ** ^The sqlite3_result_error_code() function changes the error code 3976 ** returned by SQLite as a result of an error in a function. ^By default, 3977 ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 3978 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 3979 ** 3980 ** ^The sqlite3_result_toobig() interface causes SQLite to throw an error 3981 ** indicating that a string or BLOB is too long to represent. 3982 ** 3983 ** ^The sqlite3_result_nomem() interface causes SQLite to throw an error 3984 ** indicating that a memory allocation failed. 3985 ** 3986 ** ^The sqlite3_result_int() interface sets the return value 3987 ** of the application-defined function to be the 32-bit signed integer 3988 ** value given in the 2nd argument. 3989 ** ^The sqlite3_result_int64() interface sets the return value 3990 ** of the application-defined function to be the 64-bit signed integer 3991 ** value given in the 2nd argument. 3992 ** 3993 ** ^The sqlite3_result_null() interface sets the return value 3994 ** of the application-defined function to be NULL. 3995 ** 3996 ** ^The sqlite3_result_text(), sqlite3_result_text16(), 3997 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 3998 ** set the return value of the application-defined function to be 3999 ** a text string which is represented as UTF-8, UTF-16 native byte order, 4000 ** UTF-16 little endian, or UTF-16 big endian, respectively. 4001 ** ^SQLite takes the text result from the application from 4002 ** the 2nd parameter of the sqlite3_result_text* interfaces. 4003 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4004 ** is negative, then SQLite takes result text from the 2nd parameter 4005 ** through the first zero character. 4006 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4007 ** is non-negative, then as many bytes (not characters) of the text 4008 ** pointed to by the 2nd parameter are taken as the application-defined 4009 ** function result. 4010 ** ^If the 4th parameter to the sqlite3_result_text* interfaces 4011 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4012 ** function as the destructor on the text or BLOB result when it has 4013 ** finished using that result. 4014 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4015 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4016 ** assumes that the text or BLOB result is in constant space and does not 4017 ** copy the content of the parameter nor call a destructor on the content 4018 ** when it has finished using that result. 4019 ** ^If the 4th parameter to the sqlite3_result_text* interfaces 4020 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4021 ** then SQLite makes a copy of the result into space obtained from 4022 ** from [sqlite3_malloc()] before it returns. 4023 ** 4024 ** ^The sqlite3_result_value() interface sets the result of 4025 ** the application-defined function to be a copy the 4026 ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4027 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4028 ** so that the [sqlite3_value] specified in the parameter may change or 4029 ** be deallocated after sqlite3_result_value() returns without harm. 4030 ** ^A [protected sqlite3_value] object may always be used where an 4031 ** [unprotected sqlite3_value] object is required, so either 4032 ** kind of [sqlite3_value] object can be used with this interface. 4033 ** 4034 ** If these routines are called from within the different thread 4035 ** than the one containing the application-defined function that received 4036 ** the [sqlite3_context] pointer, the results are undefined. 4037 */ 4038 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4039 SQLITE_API void sqlite3_result_double(sqlite3_context*, double); 4040 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int); 4041 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int); 4042 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*); 4043 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*); 4044 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int); 4045 SQLITE_API void sqlite3_result_int(sqlite3_context*, int); 4046 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4047 SQLITE_API void sqlite3_result_null(sqlite3_context*); 4048 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4049 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4050 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4051 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4052 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4053 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n); 4054 4055 /* 4056 ** CAPI3REF: Define New Collating Sequences 4057 ** 4058 ** ^These functions add, remove, or modify a [collation] associated 4059 ** with the [database connection] specified as the first argument. 4060 ** 4061 ** ^The name of the collation is a UTF-8 string 4062 ** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4063 ** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4064 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4065 ** considered to be the same name. 4066 ** 4067 ** ^(The third argument (eTextRep) must be one of the constants: 4068 ** <ul> 4069 ** <li> [SQLITE_UTF8], 4070 ** <li> [SQLITE_UTF16LE], 4071 ** <li> [SQLITE_UTF16BE], 4072 ** <li> [SQLITE_UTF16], or 4073 ** <li> [SQLITE_UTF16_ALIGNED]. 4074 ** </ul>)^ 4075 ** ^The eTextRep argument determines the encoding of strings passed 4076 ** to the collating function callback, xCallback. 4077 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4078 ** force strings to be UTF16 with native byte order. 4079 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4080 ** on an even byte address. 4081 ** 4082 ** ^The fourth argument, pArg, is an application data pointer that is passed 4083 ** through as the first argument to the collating function callback. 4084 ** 4085 ** ^The fifth argument, xCallback, is a pointer to the collating function. 4086 ** ^Multiple collating functions can be registered using the same name but 4087 ** with different eTextRep parameters and SQLite will use whichever 4088 ** function requires the least amount of data transformation. 4089 ** ^If the xCallback argument is NULL then the collating function is 4090 ** deleted. ^When all collating functions having the same name are deleted, 4091 ** that collation is no longer usable. 4092 ** 4093 ** ^The collating function callback is invoked with a copy of the pArg 4094 ** application data pointer and with two strings in the encoding specified 4095 ** by the eTextRep argument. The collating function must return an 4096 ** integer that is negative, zero, or positive 4097 ** if the first string is less than, equal to, or greater than the second, 4098 ** respectively. A collating function must always return the same answer 4099 ** given the same inputs. If two or more collating functions are registered 4100 ** to the same collation name (using different eTextRep values) then all 4101 ** must give an equivalent answer when invoked with equivalent strings. 4102 ** The collating function must obey the following properties for all 4103 ** strings A, B, and C: 4104 ** 4105 ** <ol> 4106 ** <li> If A==B then B==A. 4107 ** <li> If A==B and B==C then A==C. 4108 ** <li> If A<B THEN B>A. 4109 ** <li> If A<B and B<C then A<C. 4110 ** </ol> 4111 ** 4112 ** If a collating function fails any of the above constraints and that 4113 ** collating function is registered and used, then the behavior of SQLite 4114 ** is undefined. 4115 ** 4116 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4117 ** with the addition that the xDestroy callback is invoked on pArg when 4118 ** the collating function is deleted. 4119 ** ^Collating functions are deleted when they are overridden by later 4120 ** calls to the collation creation functions or when the 4121 ** [database connection] is closed using [sqlite3_close()]. 4122 ** 4123 ** ^The xDestroy callback is <u>not</u> called if the 4124 ** sqlite3_create_collation_v2() function fails. Applications that invoke 4125 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4126 ** check the return code and dispose of the application data pointer 4127 ** themselves rather than expecting SQLite to deal with it for them. 4128 ** This is different from every other SQLite interface. The inconsistency 4129 ** is unfortunate but cannot be changed without breaking backwards 4130 ** compatibility. 4131 ** 4132 ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4133 */ 4134 SQLITE_API int sqlite3_create_collation( 4135 sqlite3*, 4136 const char *zName, 4137 int eTextRep, 4138 void *pArg, 4139 int(*xCompare)(void*,int,const void*,int,const void*) 4140 ); 4141 SQLITE_API int sqlite3_create_collation_v2( 4142 sqlite3*, 4143 const char *zName, 4144 int eTextRep, 4145 void *pArg, 4146 int(*xCompare)(void*,int,const void*,int,const void*), 4147 void(*xDestroy)(void*) 4148 ); 4149 SQLITE_API int sqlite3_create_collation16( 4150 sqlite3*, 4151 const void *zName, 4152 int eTextRep, 4153 void *pArg, 4154 int(*xCompare)(void*,int,const void*,int,const void*) 4155 ); 4156 4157 /* 4158 ** CAPI3REF: Collation Needed Callbacks 4159 ** 4160 ** ^To avoid having to register all collation sequences before a database 4161 ** can be used, a single callback function may be registered with the 4162 ** [database connection] to be invoked whenever an undefined collation 4163 ** sequence is required. 4164 ** 4165 ** ^If the function is registered using the sqlite3_collation_needed() API, 4166 ** then it is passed the names of undefined collation sequences as strings 4167 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4168 ** the names are passed as UTF-16 in machine native byte order. 4169 ** ^A call to either function replaces the existing collation-needed callback. 4170 ** 4171 ** ^(When the callback is invoked, the first argument passed is a copy 4172 ** of the second argument to sqlite3_collation_needed() or 4173 ** sqlite3_collation_needed16(). The second argument is the database 4174 ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4175 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4176 ** sequence function required. The fourth parameter is the name of the 4177 ** required collation sequence.)^ 4178 ** 4179 ** The callback function should register the desired collation using 4180 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4181 ** [sqlite3_create_collation_v2()]. 4182 */ 4183 SQLITE_API int sqlite3_collation_needed( 4184 sqlite3*, 4185 void*, 4186 void(*)(void*,sqlite3*,int eTextRep,const char*) 4187 ); 4188 SQLITE_API int sqlite3_collation_needed16( 4189 sqlite3*, 4190 void*, 4191 void(*)(void*,sqlite3*,int eTextRep,const void*) 4192 ); 4193 4194 #ifdef SQLITE_HAS_CODEC 4195 /* 4196 ** Specify the key for an encrypted database. This routine should be 4197 ** called right after sqlite3_open(). 4198 ** 4199 ** The code to implement this API is not available in the public release 4200 ** of SQLite. 4201 */ 4202 SQLITE_API int sqlite3_key( 4203 sqlite3 *db, /* Database to be rekeyed */ 4204 const void *pKey, int nKey /* The key */ 4205 ); 4206 4207 /* 4208 ** Change the key on an open database. If the current database is not 4209 ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4210 ** database is decrypted. 4211 ** 4212 ** The code to implement this API is not available in the public release 4213 ** of SQLite. 4214 */ 4215 SQLITE_API int sqlite3_rekey( 4216 sqlite3 *db, /* Database to be rekeyed */ 4217 const void *pKey, int nKey /* The new key */ 4218 ); 4219 4220 /* 4221 ** Specify the activation key for a SEE database. Unless 4222 ** activated, none of the SEE routines will work. 4223 */ 4224 SQLITE_API void sqlite3_activate_see( 4225 const char *zPassPhrase /* Activation phrase */ 4226 ); 4227 #endif 4228 4229 #ifdef SQLITE_ENABLE_CEROD 4230 /* 4231 ** Specify the activation key for a CEROD database. Unless 4232 ** activated, none of the CEROD routines will work. 4233 */ 4234 SQLITE_API void sqlite3_activate_cerod( 4235 const char *zPassPhrase /* Activation phrase */ 4236 ); 4237 #endif 4238 4239 /* 4240 ** CAPI3REF: Suspend Execution For A Short Time 4241 ** 4242 ** The sqlite3_sleep() function causes the current thread to suspend execution 4243 ** for at least a number of milliseconds specified in its parameter. 4244 ** 4245 ** If the operating system does not support sleep requests with 4246 ** millisecond time resolution, then the time will be rounded up to 4247 ** the nearest second. The number of milliseconds of sleep actually 4248 ** requested from the operating system is returned. 4249 ** 4250 ** ^SQLite implements this interface by calling the xSleep() 4251 ** method of the default [sqlite3_vfs] object. If the xSleep() method 4252 ** of the default VFS is not implemented correctly, or not implemented at 4253 ** all, then the behavior of sqlite3_sleep() may deviate from the description 4254 ** in the previous paragraphs. 4255 */ 4256 SQLITE_API int sqlite3_sleep(int); 4257 4258 /* 4259 ** CAPI3REF: Name Of The Folder Holding Temporary Files 4260 ** 4261 ** ^(If this global variable is made to point to a string which is 4262 ** the name of a folder (a.k.a. directory), then all temporary files 4263 ** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4264 ** will be placed in that directory.)^ ^If this variable 4265 ** is a NULL pointer, then SQLite performs a search for an appropriate 4266 ** temporary file directory. 4267 ** 4268 ** It is not safe to read or modify this variable in more than one 4269 ** thread at a time. It is not safe to read or modify this variable 4270 ** if a [database connection] is being used at the same time in a separate 4271 ** thread. 4272 ** It is intended that this variable be set once 4273 ** as part of process initialization and before any SQLite interface 4274 ** routines have been called and that this variable remain unchanged 4275 ** thereafter. 4276 ** 4277 ** ^The [temp_store_directory pragma] may modify this variable and cause 4278 ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4279 ** the [temp_store_directory pragma] always assumes that any string 4280 ** that this variable points to is held in memory obtained from 4281 ** [sqlite3_malloc] and the pragma may attempt to free that memory 4282 ** using [sqlite3_free]. 4283 ** Hence, if this variable is modified directly, either it should be 4284 ** made NULL or made to point to memory obtained from [sqlite3_malloc] 4285 ** or else the use of the [temp_store_directory pragma] should be avoided. 4286 */ 4287 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory; 4288 4289 /* 4290 ** CAPI3REF: Test For Auto-Commit Mode 4291 ** KEYWORDS: {autocommit mode} 4292 ** 4293 ** ^The sqlite3_get_autocommit() interface returns non-zero or 4294 ** zero if the given database connection is or is not in autocommit mode, 4295 ** respectively. ^Autocommit mode is on by default. 4296 ** ^Autocommit mode is disabled by a [BEGIN] statement. 4297 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 4298 ** 4299 ** If certain kinds of errors occur on a statement within a multi-statement 4300 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 4301 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 4302 ** transaction might be rolled back automatically. The only way to 4303 ** find out whether SQLite automatically rolled back the transaction after 4304 ** an error is to use this function. 4305 ** 4306 ** If another thread changes the autocommit status of the database 4307 ** connection while this routine is running, then the return value 4308 ** is undefined. 4309 */ 4310 SQLITE_API int sqlite3_get_autocommit(sqlite3*); 4311 4312 /* 4313 ** CAPI3REF: Find The Database Handle Of A Prepared Statement 4314 ** 4315 ** ^The sqlite3_db_handle interface returns the [database connection] handle 4316 ** to which a [prepared statement] belongs. ^The [database connection] 4317 ** returned by sqlite3_db_handle is the same [database connection] 4318 ** that was the first argument 4319 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 4320 ** create the statement in the first place. 4321 */ 4322 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 4323 4324 /* 4325 ** CAPI3REF: Find the next prepared statement 4326 ** 4327 ** ^This interface returns a pointer to the next [prepared statement] after 4328 ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 4329 ** then this interface returns a pointer to the first prepared statement 4330 ** associated with the database connection pDb. ^If no prepared statement 4331 ** satisfies the conditions of this routine, it returns NULL. 4332 ** 4333 ** The [database connection] pointer D in a call to 4334 ** [sqlite3_next_stmt(D,S)] must refer to an open database 4335 ** connection and in particular must not be a NULL pointer. 4336 */ 4337 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 4338 4339 /* 4340 ** CAPI3REF: Commit And Rollback Notification Callbacks 4341 ** 4342 ** ^The sqlite3_commit_hook() interface registers a callback 4343 ** function to be invoked whenever a transaction is [COMMIT | committed]. 4344 ** ^Any callback set by a previous call to sqlite3_commit_hook() 4345 ** for the same database connection is overridden. 4346 ** ^The sqlite3_rollback_hook() interface registers a callback 4347 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 4348 ** ^Any callback set by a previous call to sqlite3_rollback_hook() 4349 ** for the same database connection is overridden. 4350 ** ^The pArg argument is passed through to the callback. 4351 ** ^If the callback on a commit hook function returns non-zero, 4352 ** then the commit is converted into a rollback. 4353 ** 4354 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 4355 ** return the P argument from the previous call of the same function 4356 ** on the same [database connection] D, or NULL for 4357 ** the first call for each function on D. 4358 ** 4359 ** The callback implementation must not do anything that will modify 4360 ** the database connection that invoked the callback. Any actions 4361 ** to modify the database connection must be deferred until after the 4362 ** completion of the [sqlite3_step()] call that triggered the commit 4363 ** or rollback hook in the first place. 4364 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4365 ** database connections for the meaning of "modify" in this paragraph. 4366 ** 4367 ** ^Registering a NULL function disables the callback. 4368 ** 4369 ** ^When the commit hook callback routine returns zero, the [COMMIT] 4370 ** operation is allowed to continue normally. ^If the commit hook 4371 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 4372 ** ^The rollback hook is invoked on a rollback that results from a commit 4373 ** hook returning non-zero, just as it would be with any other rollback. 4374 ** 4375 ** ^For the purposes of this API, a transaction is said to have been 4376 ** rolled back if an explicit "ROLLBACK" statement is executed, or 4377 ** an error or constraint causes an implicit rollback to occur. 4378 ** ^The rollback callback is not invoked if a transaction is 4379 ** automatically rolled back because the database connection is closed. 4380 ** 4381 ** See also the [sqlite3_update_hook()] interface. 4382 */ 4383 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 4384 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 4385 4386 /* 4387 ** CAPI3REF: Data Change Notification Callbacks 4388 ** 4389 ** ^The sqlite3_update_hook() interface registers a callback function 4390 ** with the [database connection] identified by the first argument 4391 ** to be invoked whenever a row is updated, inserted or deleted. 4392 ** ^Any callback set by a previous call to this function 4393 ** for the same database connection is overridden. 4394 ** 4395 ** ^The second argument is a pointer to the function to invoke when a 4396 ** row is updated, inserted or deleted. 4397 ** ^The first argument to the callback is a copy of the third argument 4398 ** to sqlite3_update_hook(). 4399 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 4400 ** or [SQLITE_UPDATE], depending on the operation that caused the callback 4401 ** to be invoked. 4402 ** ^The third and fourth arguments to the callback contain pointers to the 4403 ** database and table name containing the affected row. 4404 ** ^The final callback parameter is the [rowid] of the row. 4405 ** ^In the case of an update, this is the [rowid] after the update takes place. 4406 ** 4407 ** ^(The update hook is not invoked when internal system tables are 4408 ** modified (i.e. sqlite_master and sqlite_sequence).)^ 4409 ** 4410 ** ^In the current implementation, the update hook 4411 ** is not invoked when duplication rows are deleted because of an 4412 ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 4413 ** invoked when rows are deleted using the [truncate optimization]. 4414 ** The exceptions defined in this paragraph might change in a future 4415 ** release of SQLite. 4416 ** 4417 ** The update hook implementation must not do anything that will modify 4418 ** the database connection that invoked the update hook. Any actions 4419 ** to modify the database connection must be deferred until after the 4420 ** completion of the [sqlite3_step()] call that triggered the update hook. 4421 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4422 ** database connections for the meaning of "modify" in this paragraph. 4423 ** 4424 ** ^The sqlite3_update_hook(D,C,P) function 4425 ** returns the P argument from the previous call 4426 ** on the same [database connection] D, or NULL for 4427 ** the first call on D. 4428 ** 4429 ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4430 ** interfaces. 4431 */ 4432 SQLITE_API void *sqlite3_update_hook( 4433 sqlite3*, 4434 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4435 void* 4436 ); 4437 4438 /* 4439 ** CAPI3REF: Enable Or Disable Shared Pager Cache 4440 ** KEYWORDS: {shared cache} 4441 ** 4442 ** ^(This routine enables or disables the sharing of the database cache 4443 ** and schema data structures between [database connection | connections] 4444 ** to the same database. Sharing is enabled if the argument is true 4445 ** and disabled if the argument is false.)^ 4446 ** 4447 ** ^Cache sharing is enabled and disabled for an entire process. 4448 ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4449 ** sharing was enabled or disabled for each thread separately. 4450 ** 4451 ** ^(The cache sharing mode set by this interface effects all subsequent 4452 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4453 ** Existing database connections continue use the sharing mode 4454 ** that was in effect at the time they were opened.)^ 4455 ** 4456 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4457 ** successfully. An [error code] is returned otherwise.)^ 4458 ** 4459 ** ^Shared cache is disabled by default. But this might change in 4460 ** future releases of SQLite. Applications that care about shared 4461 ** cache setting should set it explicitly. 4462 ** 4463 ** See Also: [SQLite Shared-Cache Mode] 4464 */ 4465 SQLITE_API int sqlite3_enable_shared_cache(int); 4466 4467 /* 4468 ** CAPI3REF: Attempt To Free Heap Memory 4469 ** 4470 ** ^The sqlite3_release_memory() interface attempts to free N bytes 4471 ** of heap memory by deallocating non-essential memory allocations 4472 ** held by the database library. Memory used to cache database 4473 ** pages to improve performance is an example of non-essential memory. 4474 ** ^sqlite3_release_memory() returns the number of bytes actually freed, 4475 ** which might be more or less than the amount requested. 4476 ** ^The sqlite3_release_memory() routine is a no-op returning zero 4477 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4478 */ 4479 SQLITE_API int sqlite3_release_memory(int); 4480 4481 /* 4482 ** CAPI3REF: Impose A Limit On Heap Size 4483 ** 4484 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 4485 ** soft limit on the amount of heap memory that may be allocated by SQLite. 4486 ** ^SQLite strives to keep heap memory utilization below the soft heap 4487 ** limit by reducing the number of pages held in the page cache 4488 ** as heap memory usages approaches the limit. 4489 ** ^The soft heap limit is "soft" because even though SQLite strives to stay 4490 ** below the limit, it will exceed the limit rather than generate 4491 ** an [SQLITE_NOMEM] error. In other words, the soft heap limit 4492 ** is advisory only. 4493 ** 4494 ** ^The return value from sqlite3_soft_heap_limit64() is the size of 4495 ** the soft heap limit prior to the call. ^If the argument N is negative 4496 ** then no change is made to the soft heap limit. Hence, the current 4497 ** size of the soft heap limit can be determined by invoking 4498 ** sqlite3_soft_heap_limit64() with a negative argument. 4499 ** 4500 ** ^If the argument N is zero then the soft heap limit is disabled. 4501 ** 4502 ** ^(The soft heap limit is not enforced in the current implementation 4503 ** if one or more of following conditions are true: 4504 ** 4505 ** <ul> 4506 ** <li> The soft heap limit is set to zero. 4507 ** <li> Memory accounting is disabled using a combination of the 4508 ** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 4509 ** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 4510 ** <li> An alternative page cache implementation is specified using 4511 ** [sqlite3_config]([SQLITE_CONFIG_PCACHE],...). 4512 ** <li> The page cache allocates from its own memory pool supplied 4513 ** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 4514 ** from the heap. 4515 ** </ul>)^ 4516 ** 4517 ** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 4518 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 4519 ** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 4520 ** the soft heap limit is enforced on every memory allocation. Without 4521 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 4522 ** when memory is allocated by the page cache. Testing suggests that because 4523 ** the page cache is the predominate memory user in SQLite, most 4524 ** applications will achieve adequate soft heap limit enforcement without 4525 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4526 ** 4527 ** The circumstances under which SQLite will enforce the soft heap limit may 4528 ** changes in future releases of SQLite. 4529 */ 4530 SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 4531 4532 /* 4533 ** CAPI3REF: Deprecated Soft Heap Limit Interface 4534 ** DEPRECATED 4535 ** 4536 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 4537 ** interface. This routine is provided for historical compatibility 4538 ** only. All new applications should use the 4539 ** [sqlite3_soft_heap_limit64()] interface rather than this one. 4540 */ 4541 SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 4542 4543 4544 /* 4545 ** CAPI3REF: Extract Metadata About A Column Of A Table 4546 ** 4547 ** ^This routine returns metadata about a specific column of a specific 4548 ** database table accessible using the [database connection] handle 4549 ** passed as the first function argument. 4550 ** 4551 ** ^The column is identified by the second, third and fourth parameters to 4552 ** this function. ^The second parameter is either the name of the database 4553 ** (i.e. "main", "temp", or an attached database) containing the specified 4554 ** table or NULL. ^If it is NULL, then all attached databases are searched 4555 ** for the table using the same algorithm used by the database engine to 4556 ** resolve unqualified table references. 4557 ** 4558 ** ^The third and fourth parameters to this function are the table and column 4559 ** name of the desired column, respectively. Neither of these parameters 4560 ** may be NULL. 4561 ** 4562 ** ^Metadata is returned by writing to the memory locations passed as the 5th 4563 ** and subsequent parameters to this function. ^Any of these arguments may be 4564 ** NULL, in which case the corresponding element of metadata is omitted. 4565 ** 4566 ** ^(<blockquote> 4567 ** <table border="1"> 4568 ** <tr><th> Parameter <th> Output<br>Type <th> Description 4569 ** 4570 ** <tr><td> 5th <td> const char* <td> Data type 4571 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4572 ** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4573 ** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4574 ** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4575 ** </table> 4576 ** </blockquote>)^ 4577 ** 4578 ** ^The memory pointed to by the character pointers returned for the 4579 ** declaration type and collation sequence is valid only until the next 4580 ** call to any SQLite API function. 4581 ** 4582 ** ^If the specified table is actually a view, an [error code] is returned. 4583 ** 4584 ** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4585 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4586 ** parameters are set for the explicitly declared column. ^(If there is no 4587 ** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4588 ** parameters are set as follows: 4589 ** 4590 ** <pre> 4591 ** data type: "INTEGER" 4592 ** collation sequence: "BINARY" 4593 ** not null: 0 4594 ** primary key: 1 4595 ** auto increment: 0 4596 ** </pre>)^ 4597 ** 4598 ** ^(This function may load one or more schemas from database files. If an 4599 ** error occurs during this process, or if the requested table or column 4600 ** cannot be found, an [error code] is returned and an error message left 4601 ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4602 ** 4603 ** ^This API is only available if the library was compiled with the 4604 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4605 */ 4606 SQLITE_API int sqlite3_table_column_metadata( 4607 sqlite3 *db, /* Connection handle */ 4608 const char *zDbName, /* Database name or NULL */ 4609 const char *zTableName, /* Table name */ 4610 const char *zColumnName, /* Column name */ 4611 char const **pzDataType, /* OUTPUT: Declared data type */ 4612 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4613 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4614 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4615 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4616 ); 4617 4618 /* 4619 ** CAPI3REF: Load An Extension 4620 ** 4621 ** ^This interface loads an SQLite extension library from the named file. 4622 ** 4623 ** ^The sqlite3_load_extension() interface attempts to load an 4624 ** SQLite extension library contained in the file zFile. 4625 ** 4626 ** ^The entry point is zProc. 4627 ** ^zProc may be 0, in which case the name of the entry point 4628 ** defaults to "sqlite3_extension_init". 4629 ** ^The sqlite3_load_extension() interface returns 4630 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4631 ** ^If an error occurs and pzErrMsg is not 0, then the 4632 ** [sqlite3_load_extension()] interface shall attempt to 4633 ** fill *pzErrMsg with error message text stored in memory 4634 ** obtained from [sqlite3_malloc()]. The calling function 4635 ** should free this memory by calling [sqlite3_free()]. 4636 ** 4637 ** ^Extension loading must be enabled using 4638 ** [sqlite3_enable_load_extension()] prior to calling this API, 4639 ** otherwise an error will be returned. 4640 ** 4641 ** See also the [load_extension() SQL function]. 4642 */ 4643 SQLITE_API int sqlite3_load_extension( 4644 sqlite3 *db, /* Load the extension into this database connection */ 4645 const char *zFile, /* Name of the shared library containing extension */ 4646 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4647 char **pzErrMsg /* Put error message here if not 0 */ 4648 ); 4649 4650 /* 4651 ** CAPI3REF: Enable Or Disable Extension Loading 4652 ** 4653 ** ^So as not to open security holes in older applications that are 4654 ** unprepared to deal with extension loading, and as a means of disabling 4655 ** extension loading while evaluating user-entered SQL, the following API 4656 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4657 ** 4658 ** ^Extension loading is off by default. See ticket #1863. 4659 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1 4660 ** to turn extension loading on and call it with onoff==0 to turn 4661 ** it back off again. 4662 */ 4663 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4664 4665 /* 4666 ** CAPI3REF: Automatically Load Statically Linked Extensions 4667 ** 4668 ** ^This interface causes the xEntryPoint() function to be invoked for 4669 ** each new [database connection] that is created. The idea here is that 4670 ** xEntryPoint() is the entry point for a statically linked SQLite extension 4671 ** that is to be automatically loaded into all new database connections. 4672 ** 4673 ** ^(Even though the function prototype shows that xEntryPoint() takes 4674 ** no arguments and returns void, SQLite invokes xEntryPoint() with three 4675 ** arguments and expects and integer result as if the signature of the 4676 ** entry point where as follows: 4677 ** 4678 ** <blockquote><pre> 4679 ** int xEntryPoint( 4680 ** sqlite3 *db, 4681 ** const char **pzErrMsg, 4682 ** const struct sqlite3_api_routines *pThunk 4683 ** ); 4684 ** </pre></blockquote>)^ 4685 ** 4686 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 4687 ** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 4688 ** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 4689 ** is NULL before calling the xEntryPoint(). ^SQLite will invoke 4690 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 4691 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 4692 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 4693 ** 4694 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 4695 ** on the list of automatic extensions is a harmless no-op. ^No entry point 4696 ** will be called more than once for each database connection that is opened. 4697 ** 4698 ** See also: [sqlite3_reset_auto_extension()]. 4699 */ 4700 SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4701 4702 /* 4703 ** CAPI3REF: Reset Automatic Extension Loading 4704 ** 4705 ** ^This interface disables all automatic extensions previously 4706 ** registered using [sqlite3_auto_extension()]. 4707 */ 4708 SQLITE_API void sqlite3_reset_auto_extension(void); 4709 4710 /* 4711 ** The interface to the virtual-table mechanism is currently considered 4712 ** to be experimental. The interface might change in incompatible ways. 4713 ** If this is a problem for you, do not use the interface at this time. 4714 ** 4715 ** When the virtual-table mechanism stabilizes, we will declare the 4716 ** interface fixed, support it indefinitely, and remove this comment. 4717 */ 4718 4719 /* 4720 ** Structures used by the virtual table interface 4721 */ 4722 typedef struct sqlite3_vtab sqlite3_vtab; 4723 typedef struct sqlite3_index_info sqlite3_index_info; 4724 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4725 typedef struct sqlite3_module sqlite3_module; 4726 4727 /* 4728 ** CAPI3REF: Virtual Table Object 4729 ** KEYWORDS: sqlite3_module {virtual table module} 4730 ** 4731 ** This structure, sometimes called a "virtual table module", 4732 ** defines the implementation of a [virtual tables]. 4733 ** This structure consists mostly of methods for the module. 4734 ** 4735 ** ^A virtual table module is created by filling in a persistent 4736 ** instance of this structure and passing a pointer to that instance 4737 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4738 ** ^The registration remains valid until it is replaced by a different 4739 ** module or until the [database connection] closes. The content 4740 ** of this structure must not change while it is registered with 4741 ** any database connection. 4742 */ 4743 struct sqlite3_module { 4744 int iVersion; 4745 int (*xCreate)(sqlite3*, void *pAux, 4746 int argc, const char *const*argv, 4747 sqlite3_vtab **ppVTab, char**); 4748 int (*xConnect)(sqlite3*, void *pAux, 4749 int argc, const char *const*argv, 4750 sqlite3_vtab **ppVTab, char**); 4751 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4752 int (*xDisconnect)(sqlite3_vtab *pVTab); 4753 int (*xDestroy)(sqlite3_vtab *pVTab); 4754 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4755 int (*xClose)(sqlite3_vtab_cursor*); 4756 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4757 int argc, sqlite3_value **argv); 4758 int (*xNext)(sqlite3_vtab_cursor*); 4759 int (*xEof)(sqlite3_vtab_cursor*); 4760 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4761 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4762 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4763 int (*xBegin)(sqlite3_vtab *pVTab); 4764 int (*xSync)(sqlite3_vtab *pVTab); 4765 int (*xCommit)(sqlite3_vtab *pVTab); 4766 int (*xRollback)(sqlite3_vtab *pVTab); 4767 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4768 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4769 void **ppArg); 4770 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4771 /* The methods above are in version 1 of the sqlite_module object. Those 4772 ** below are for version 2 and greater. */ 4773 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 4774 int (*xRelease)(sqlite3_vtab *pVTab, int); 4775 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 4776 }; 4777 4778 /* 4779 ** CAPI3REF: Virtual Table Indexing Information 4780 ** KEYWORDS: sqlite3_index_info 4781 ** 4782 ** The sqlite3_index_info structure and its substructures is used as part 4783 ** of the [virtual table] interface to 4784 ** pass information into and receive the reply from the [xBestIndex] 4785 ** method of a [virtual table module]. The fields under **Inputs** are the 4786 ** inputs to xBestIndex and are read-only. xBestIndex inserts its 4787 ** results into the **Outputs** fields. 4788 ** 4789 ** ^(The aConstraint[] array records WHERE clause constraints of the form: 4790 ** 4791 ** <blockquote>column OP expr</blockquote> 4792 ** 4793 ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 4794 ** stored in aConstraint[].op using one of the 4795 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 4796 ** ^(The index of the column is stored in 4797 ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 4798 ** expr on the right-hand side can be evaluated (and thus the constraint 4799 ** is usable) and false if it cannot.)^ 4800 ** 4801 ** ^The optimizer automatically inverts terms of the form "expr OP column" 4802 ** and makes other simplifications to the WHERE clause in an attempt to 4803 ** get as many WHERE clause terms into the form shown above as possible. 4804 ** ^The aConstraint[] array only reports WHERE clause terms that are 4805 ** relevant to the particular virtual table being queried. 4806 ** 4807 ** ^Information about the ORDER BY clause is stored in aOrderBy[]. 4808 ** ^Each term of aOrderBy records a column of the ORDER BY clause. 4809 ** 4810 ** The [xBestIndex] method must fill aConstraintUsage[] with information 4811 ** about what parameters to pass to xFilter. ^If argvIndex>0 then 4812 ** the right-hand side of the corresponding aConstraint[] is evaluated 4813 ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 4814 ** is true, then the constraint is assumed to be fully handled by the 4815 ** virtual table and is not checked again by SQLite.)^ 4816 ** 4817 ** ^The idxNum and idxPtr values are recorded and passed into the 4818 ** [xFilter] method. 4819 ** ^[sqlite3_free()] is used to free idxPtr if and only if 4820 ** needToFreeIdxPtr is true. 4821 ** 4822 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 4823 ** the correct order to satisfy the ORDER BY clause so that no separate 4824 ** sorting step is required. 4825 ** 4826 ** ^The estimatedCost value is an estimate of the cost of doing the 4827 ** particular lookup. A full scan of a table with N entries should have 4828 ** a cost of N. A binary search of a table of N entries should have a 4829 ** cost of approximately log(N). 4830 */ 4831 struct sqlite3_index_info { 4832 /* Inputs */ 4833 int nConstraint; /* Number of entries in aConstraint */ 4834 struct sqlite3_index_constraint { 4835 int iColumn; /* Column on left-hand side of constraint */ 4836 unsigned char op; /* Constraint operator */ 4837 unsigned char usable; /* True if this constraint is usable */ 4838 int iTermOffset; /* Used internally - xBestIndex should ignore */ 4839 } *aConstraint; /* Table of WHERE clause constraints */ 4840 int nOrderBy; /* Number of terms in the ORDER BY clause */ 4841 struct sqlite3_index_orderby { 4842 int iColumn; /* Column number */ 4843 unsigned char desc; /* True for DESC. False for ASC. */ 4844 } *aOrderBy; /* The ORDER BY clause */ 4845 /* Outputs */ 4846 struct sqlite3_index_constraint_usage { 4847 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 4848 unsigned char omit; /* Do not code a test for this constraint */ 4849 } *aConstraintUsage; 4850 int idxNum; /* Number used to identify the index */ 4851 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 4852 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 4853 int orderByConsumed; /* True if output is already ordered */ 4854 double estimatedCost; /* Estimated cost of using this index */ 4855 }; 4856 4857 /* 4858 ** CAPI3REF: Virtual Table Constraint Operator Codes 4859 ** 4860 ** These macros defined the allowed values for the 4861 ** [sqlite3_index_info].aConstraint[].op field. Each value represents 4862 ** an operator that is part of a constraint term in the wHERE clause of 4863 ** a query that uses a [virtual table]. 4864 */ 4865 #define SQLITE_INDEX_CONSTRAINT_EQ 2 4866 #define SQLITE_INDEX_CONSTRAINT_GT 4 4867 #define SQLITE_INDEX_CONSTRAINT_LE 8 4868 #define SQLITE_INDEX_CONSTRAINT_LT 16 4869 #define SQLITE_INDEX_CONSTRAINT_GE 32 4870 #define SQLITE_INDEX_CONSTRAINT_MATCH 64 4871 4872 /* 4873 ** CAPI3REF: Register A Virtual Table Implementation 4874 ** 4875 ** ^These routines are used to register a new [virtual table module] name. 4876 ** ^Module names must be registered before 4877 ** creating a new [virtual table] using the module and before using a 4878 ** preexisting [virtual table] for the module. 4879 ** 4880 ** ^The module name is registered on the [database connection] specified 4881 ** by the first parameter. ^The name of the module is given by the 4882 ** second parameter. ^The third parameter is a pointer to 4883 ** the implementation of the [virtual table module]. ^The fourth 4884 ** parameter is an arbitrary client data pointer that is passed through 4885 ** into the [xCreate] and [xConnect] methods of the virtual table module 4886 ** when a new virtual table is be being created or reinitialized. 4887 ** 4888 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which 4889 ** is a pointer to a destructor for the pClientData. ^SQLite will 4890 ** invoke the destructor function (if it is not NULL) when SQLite 4891 ** no longer needs the pClientData pointer. ^The destructor will also 4892 ** be invoked if the call to sqlite3_create_module_v2() fails. 4893 ** ^The sqlite3_create_module() 4894 ** interface is equivalent to sqlite3_create_module_v2() with a NULL 4895 ** destructor. 4896 */ 4897 SQLITE_API int sqlite3_create_module( 4898 sqlite3 *db, /* SQLite connection to register module with */ 4899 const char *zName, /* Name of the module */ 4900 const sqlite3_module *p, /* Methods for the module */ 4901 void *pClientData /* Client data for xCreate/xConnect */ 4902 ); 4903 SQLITE_API int sqlite3_create_module_v2( 4904 sqlite3 *db, /* SQLite connection to register module with */ 4905 const char *zName, /* Name of the module */ 4906 const sqlite3_module *p, /* Methods for the module */ 4907 void *pClientData, /* Client data for xCreate/xConnect */ 4908 void(*xDestroy)(void*) /* Module destructor function */ 4909 ); 4910 4911 /* 4912 ** CAPI3REF: Virtual Table Instance Object 4913 ** KEYWORDS: sqlite3_vtab 4914 ** 4915 ** Every [virtual table module] implementation uses a subclass 4916 ** of this object to describe a particular instance 4917 ** of the [virtual table]. Each subclass will 4918 ** be tailored to the specific needs of the module implementation. 4919 ** The purpose of this superclass is to define certain fields that are 4920 ** common to all module implementations. 4921 ** 4922 ** ^Virtual tables methods can set an error message by assigning a 4923 ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 4924 ** take care that any prior string is freed by a call to [sqlite3_free()] 4925 ** prior to assigning a new string to zErrMsg. ^After the error message 4926 ** is delivered up to the client application, the string will be automatically 4927 ** freed by sqlite3_free() and the zErrMsg field will be zeroed. 4928 */ 4929 struct sqlite3_vtab { 4930 const sqlite3_module *pModule; /* The module for this virtual table */ 4931 int nRef; /* NO LONGER USED */ 4932 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 4933 /* Virtual table implementations will typically add additional fields */ 4934 }; 4935 4936 /* 4937 ** CAPI3REF: Virtual Table Cursor Object 4938 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 4939 ** 4940 ** Every [virtual table module] implementation uses a subclass of the 4941 ** following structure to describe cursors that point into the 4942 ** [virtual table] and are used 4943 ** to loop through the virtual table. Cursors are created using the 4944 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 4945 ** by the [sqlite3_module.xClose | xClose] method. Cursors are used 4946 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 4947 ** of the module. Each module implementation will define 4948 ** the content of a cursor structure to suit its own needs. 4949 ** 4950 ** This superclass exists in order to define fields of the cursor that 4951 ** are common to all implementations. 4952 */ 4953 struct sqlite3_vtab_cursor { 4954 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 4955 /* Virtual table implementations will typically add additional fields */ 4956 }; 4957 4958 /* 4959 ** CAPI3REF: Declare The Schema Of A Virtual Table 4960 ** 4961 ** ^The [xCreate] and [xConnect] methods of a 4962 ** [virtual table module] call this interface 4963 ** to declare the format (the names and datatypes of the columns) of 4964 ** the virtual tables they implement. 4965 */ 4966 SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 4967 4968 /* 4969 ** CAPI3REF: Overload A Function For A Virtual Table 4970 ** 4971 ** ^(Virtual tables can provide alternative implementations of functions 4972 ** using the [xFindFunction] method of the [virtual table module]. 4973 ** But global versions of those functions 4974 ** must exist in order to be overloaded.)^ 4975 ** 4976 ** ^(This API makes sure a global version of a function with a particular 4977 ** name and number of parameters exists. If no such function exists 4978 ** before this API is called, a new function is created.)^ ^The implementation 4979 ** of the new function always causes an exception to be thrown. So 4980 ** the new function is not good for anything by itself. Its only 4981 ** purpose is to be a placeholder function that can be overloaded 4982 ** by a [virtual table]. 4983 */ 4984 SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 4985 4986 /* 4987 ** The interface to the virtual-table mechanism defined above (back up 4988 ** to a comment remarkably similar to this one) is currently considered 4989 ** to be experimental. The interface might change in incompatible ways. 4990 ** If this is a problem for you, do not use the interface at this time. 4991 ** 4992 ** When the virtual-table mechanism stabilizes, we will declare the 4993 ** interface fixed, support it indefinitely, and remove this comment. 4994 */ 4995 4996 /* 4997 ** CAPI3REF: A Handle To An Open BLOB 4998 ** KEYWORDS: {BLOB handle} {BLOB handles} 4999 ** 5000 ** An instance of this object represents an open BLOB on which 5001 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5002 ** ^Objects of this type are created by [sqlite3_blob_open()] 5003 ** and destroyed by [sqlite3_blob_close()]. 5004 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5005 ** can be used to read or write small subsections of the BLOB. 5006 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5007 */ 5008 typedef struct sqlite3_blob sqlite3_blob; 5009 5010 /* 5011 ** CAPI3REF: Open A BLOB For Incremental I/O 5012 ** 5013 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5014 ** in row iRow, column zColumn, table zTable in database zDb; 5015 ** in other words, the same BLOB that would be selected by: 5016 ** 5017 ** <pre> 5018 ** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5019 ** </pre>)^ 5020 ** 5021 ** ^If the flags parameter is non-zero, then the BLOB is opened for read 5022 ** and write access. ^If it is zero, the BLOB is opened for read access. 5023 ** ^It is not possible to open a column that is part of an index or primary 5024 ** key for writing. ^If [foreign key constraints] are enabled, it is 5025 ** not possible to open a column that is part of a [child key] for writing. 5026 ** 5027 ** ^Note that the database name is not the filename that contains 5028 ** the database but rather the symbolic name of the database that 5029 ** appears after the AS keyword when the database is connected using [ATTACH]. 5030 ** ^For the main database file, the database name is "main". 5031 ** ^For TEMP tables, the database name is "temp". 5032 ** 5033 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 5034 ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 5035 ** to be a null pointer.)^ 5036 ** ^This function sets the [database connection] error code and message 5037 ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 5038 ** functions. ^Note that the *ppBlob variable is always initialized in a 5039 ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 5040 ** regardless of the success or failure of this routine. 5041 ** 5042 ** ^(If the row that a BLOB handle points to is modified by an 5043 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5044 ** then the BLOB handle is marked as "expired". 5045 ** This is true if any column of the row is changed, even a column 5046 ** other than the one the BLOB handle is open on.)^ 5047 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5048 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5049 ** ^(Changes written into a BLOB prior to the BLOB expiring are not 5050 ** rolled back by the expiration of the BLOB. Such changes will eventually 5051 ** commit if the transaction continues to completion.)^ 5052 ** 5053 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5054 ** the opened blob. ^The size of a blob may not be changed by this 5055 ** interface. Use the [UPDATE] SQL command to change the size of a 5056 ** blob. 5057 ** 5058 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5059 ** and the built-in [zeroblob] SQL function can be used, if desired, 5060 ** to create an empty, zero-filled blob in which to read or write using 5061 ** this interface. 5062 ** 5063 ** To avoid a resource leak, every open [BLOB handle] should eventually 5064 ** be released by a call to [sqlite3_blob_close()]. 5065 */ 5066 SQLITE_API int sqlite3_blob_open( 5067 sqlite3*, 5068 const char *zDb, 5069 const char *zTable, 5070 const char *zColumn, 5071 sqlite3_int64 iRow, 5072 int flags, 5073 sqlite3_blob **ppBlob 5074 ); 5075 5076 /* 5077 ** CAPI3REF: Move a BLOB Handle to a New Row 5078 ** 5079 ** ^This function is used to move an existing blob handle so that it points 5080 ** to a different row of the same database table. ^The new row is identified 5081 ** by the rowid value passed as the second argument. Only the row can be 5082 ** changed. ^The database, table and column on which the blob handle is open 5083 ** remain the same. Moving an existing blob handle to a new row can be 5084 ** faster than closing the existing handle and opening a new one. 5085 ** 5086 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5087 ** it must exist and there must be either a blob or text value stored in 5088 ** the nominated column.)^ ^If the new row is not present in the table, or if 5089 ** it does not contain a blob or text value, or if another error occurs, an 5090 ** SQLite error code is returned and the blob handle is considered aborted. 5091 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5092 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5093 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5094 ** always returns zero. 5095 ** 5096 ** ^This function sets the database handle error code and message. 5097 */ 5098 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5099 5100 /* 5101 ** CAPI3REF: Close A BLOB Handle 5102 ** 5103 ** ^Closes an open [BLOB handle]. 5104 ** 5105 ** ^Closing a BLOB shall cause the current transaction to commit 5106 ** if there are no other BLOBs, no pending prepared statements, and the 5107 ** database connection is in [autocommit mode]. 5108 ** ^If any writes were made to the BLOB, they might be held in cache 5109 ** until the close operation if they will fit. 5110 ** 5111 ** ^(Closing the BLOB often forces the changes 5112 ** out to disk and so if any I/O errors occur, they will likely occur 5113 ** at the time when the BLOB is closed. Any errors that occur during 5114 ** closing are reported as a non-zero return value.)^ 5115 ** 5116 ** ^(The BLOB is closed unconditionally. Even if this routine returns 5117 ** an error code, the BLOB is still closed.)^ 5118 ** 5119 ** ^Calling this routine with a null pointer (such as would be returned 5120 ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 5121 */ 5122 SQLITE_API int sqlite3_blob_close(sqlite3_blob *); 5123 5124 /* 5125 ** CAPI3REF: Return The Size Of An Open BLOB 5126 ** 5127 ** ^Returns the size in bytes of the BLOB accessible via the 5128 ** successfully opened [BLOB handle] in its only argument. ^The 5129 ** incremental blob I/O routines can only read or overwriting existing 5130 ** blob content; they cannot change the size of a blob. 5131 ** 5132 ** This routine only works on a [BLOB handle] which has been created 5133 ** by a prior successful call to [sqlite3_blob_open()] and which has not 5134 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5135 ** to this routine results in undefined and probably undesirable behavior. 5136 */ 5137 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *); 5138 5139 /* 5140 ** CAPI3REF: Read Data From A BLOB Incrementally 5141 ** 5142 ** ^(This function is used to read data from an open [BLOB handle] into a 5143 ** caller-supplied buffer. N bytes of data are copied into buffer Z 5144 ** from the open BLOB, starting at offset iOffset.)^ 5145 ** 5146 ** ^If offset iOffset is less than N bytes from the end of the BLOB, 5147 ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 5148 ** less than zero, [SQLITE_ERROR] is returned and no data is read. 5149 ** ^The size of the blob (and hence the maximum value of N+iOffset) 5150 ** can be determined using the [sqlite3_blob_bytes()] interface. 5151 ** 5152 ** ^An attempt to read from an expired [BLOB handle] fails with an 5153 ** error code of [SQLITE_ABORT]. 5154 ** 5155 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 5156 ** Otherwise, an [error code] or an [extended error code] is returned.)^ 5157 ** 5158 ** This routine only works on a [BLOB handle] which has been created 5159 ** by a prior successful call to [sqlite3_blob_open()] and which has not 5160 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5161 ** to this routine results in undefined and probably undesirable behavior. 5162 ** 5163 ** See also: [sqlite3_blob_write()]. 5164 */ 5165 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 5166 5167 /* 5168 ** CAPI3REF: Write Data Into A BLOB Incrementally 5169 ** 5170 ** ^This function is used to write data into an open [BLOB handle] from a 5171 ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 5172 ** into the open BLOB, starting at offset iOffset. 5173 ** 5174 ** ^If the [BLOB handle] passed as the first argument was not opened for 5175 ** writing (the flags parameter to [sqlite3_blob_open()] was zero), 5176 ** this function returns [SQLITE_READONLY]. 5177 ** 5178 ** ^This function may only modify the contents of the BLOB; it is 5179 ** not possible to increase the size of a BLOB using this API. 5180 ** ^If offset iOffset is less than N bytes from the end of the BLOB, 5181 ** [SQLITE_ERROR] is returned and no data is written. ^If N is 5182 ** less than zero [SQLITE_ERROR] is returned and no data is written. 5183 ** The size of the BLOB (and hence the maximum value of N+iOffset) 5184 ** can be determined using the [sqlite3_blob_bytes()] interface. 5185 ** 5186 ** ^An attempt to write to an expired [BLOB handle] fails with an 5187 ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 5188 ** before the [BLOB handle] expired are not rolled back by the 5189 ** expiration of the handle, though of course those changes might 5190 ** have been overwritten by the statement that expired the BLOB handle 5191 ** or by other independent statements. 5192 ** 5193 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 5194 ** Otherwise, an [error code] or an [extended error code] is returned.)^ 5195 ** 5196 ** This routine only works on a [BLOB handle] which has been created 5197 ** by a prior successful call to [sqlite3_blob_open()] and which has not 5198 ** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5199 ** to this routine results in undefined and probably undesirable behavior. 5200 ** 5201 ** See also: [sqlite3_blob_read()]. 5202 */ 5203 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 5204 5205 /* 5206 ** CAPI3REF: Virtual File System Objects 5207 ** 5208 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object 5209 ** that SQLite uses to interact 5210 ** with the underlying operating system. Most SQLite builds come with a 5211 ** single default VFS that is appropriate for the host computer. 5212 ** New VFSes can be registered and existing VFSes can be unregistered. 5213 ** The following interfaces are provided. 5214 ** 5215 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 5216 ** ^Names are case sensitive. 5217 ** ^Names are zero-terminated UTF-8 strings. 5218 ** ^If there is no match, a NULL pointer is returned. 5219 ** ^If zVfsName is NULL then the default VFS is returned. 5220 ** 5221 ** ^New VFSes are registered with sqlite3_vfs_register(). 5222 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 5223 ** ^The same VFS can be registered multiple times without injury. 5224 ** ^To make an existing VFS into the default VFS, register it again 5225 ** with the makeDflt flag set. If two different VFSes with the 5226 ** same name are registered, the behavior is undefined. If a 5227 ** VFS is registered with a name that is NULL or an empty string, 5228 ** then the behavior is undefined. 5229 ** 5230 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 5231 ** ^(If the default VFS is unregistered, another VFS is chosen as 5232 ** the default. The choice for the new VFS is arbitrary.)^ 5233 */ 5234 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 5235 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 5236 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*); 5237 5238 /* 5239 ** CAPI3REF: Mutexes 5240 ** 5241 ** The SQLite core uses these routines for thread 5242 ** synchronization. Though they are intended for internal 5243 ** use by SQLite, code that links against SQLite is 5244 ** permitted to use any of these routines. 5245 ** 5246 ** The SQLite source code contains multiple implementations 5247 ** of these mutex routines. An appropriate implementation 5248 ** is selected automatically at compile-time. ^(The following 5249 ** implementations are available in the SQLite core: 5250 ** 5251 ** <ul> 5252 ** <li> SQLITE_MUTEX_OS2 5253 ** <li> SQLITE_MUTEX_PTHREAD 5254 ** <li> SQLITE_MUTEX_W32 5255 ** <li> SQLITE_MUTEX_NOOP 5256 ** </ul>)^ 5257 ** 5258 ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 5259 ** that does no real locking and is appropriate for use in 5260 ** a single-threaded application. ^The SQLITE_MUTEX_OS2, 5261 ** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations 5262 ** are appropriate for use on OS/2, Unix, and Windows. 5263 ** 5264 ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 5265 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 5266 ** implementation is included with the library. In this case the 5267 ** application must supply a custom mutex implementation using the 5268 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 5269 ** before calling sqlite3_initialize() or any other public sqlite3_ 5270 ** function that calls sqlite3_initialize().)^ 5271 ** 5272 ** ^The sqlite3_mutex_alloc() routine allocates a new 5273 ** mutex and returns a pointer to it. ^If it returns NULL 5274 ** that means that a mutex could not be allocated. ^SQLite 5275 ** will unwind its stack and return an error. ^(The argument 5276 ** to sqlite3_mutex_alloc() is one of these integer constants: 5277 ** 5278 ** <ul> 5279 ** <li> SQLITE_MUTEX_FAST 5280 ** <li> SQLITE_MUTEX_RECURSIVE 5281 ** <li> SQLITE_MUTEX_STATIC_MASTER 5282 ** <li> SQLITE_MUTEX_STATIC_MEM 5283 ** <li> SQLITE_MUTEX_STATIC_MEM2 5284 ** <li> SQLITE_MUTEX_STATIC_PRNG 5285 ** <li> SQLITE_MUTEX_STATIC_LRU 5286 ** <li> SQLITE_MUTEX_STATIC_LRU2 5287 ** </ul>)^ 5288 ** 5289 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 5290 ** cause sqlite3_mutex_alloc() to create 5291 ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 5292 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 5293 ** The mutex implementation does not need to make a distinction 5294 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 5295 ** not want to. ^SQLite will only request a recursive mutex in 5296 ** cases where it really needs one. ^If a faster non-recursive mutex 5297 ** implementation is available on the host platform, the mutex subsystem 5298 ** might return such a mutex in response to SQLITE_MUTEX_FAST. 5299 ** 5300 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 5301 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 5302 ** a pointer to a static preexisting mutex. ^Six static mutexes are 5303 ** used by the current version of SQLite. Future versions of SQLite 5304 ** may add additional static mutexes. Static mutexes are for internal 5305 ** use by SQLite only. Applications that use SQLite mutexes should 5306 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 5307 ** SQLITE_MUTEX_RECURSIVE. 5308 ** 5309 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 5310 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 5311 ** returns a different mutex on every call. ^But for the static 5312 ** mutex types, the same mutex is returned on every call that has 5313 ** the same type number. 5314 ** 5315 ** ^The sqlite3_mutex_free() routine deallocates a previously 5316 ** allocated dynamic mutex. ^SQLite is careful to deallocate every 5317 ** dynamic mutex that it allocates. The dynamic mutexes must not be in 5318 ** use when they are deallocated. Attempting to deallocate a static 5319 ** mutex results in undefined behavior. ^SQLite never deallocates 5320 ** a static mutex. 5321 ** 5322 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 5323 ** to enter a mutex. ^If another thread is already within the mutex, 5324 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 5325 ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 5326 ** upon successful entry. ^(Mutexes created using 5327 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 5328 ** In such cases the, 5329 ** mutex must be exited an equal number of times before another thread 5330 ** can enter.)^ ^(If the same thread tries to enter any other 5331 ** kind of mutex more than once, the behavior is undefined. 5332 ** SQLite will never exhibit 5333 ** such behavior in its own use of mutexes.)^ 5334 ** 5335 ** ^(Some systems (for example, Windows 95) do not support the operation 5336 ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 5337 ** will always return SQLITE_BUSY. The SQLite core only ever uses 5338 ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 5339 ** 5340 ** ^The sqlite3_mutex_leave() routine exits a mutex that was 5341 ** previously entered by the same thread. ^(The behavior 5342 ** is undefined if the mutex is not currently entered by the 5343 ** calling thread or is not currently allocated. SQLite will 5344 ** never do either.)^ 5345 ** 5346 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 5347 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines 5348 ** behave as no-ops. 5349 ** 5350 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 5351 */ 5352 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int); 5353 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*); 5354 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*); 5355 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*); 5356 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*); 5357 5358 /* 5359 ** CAPI3REF: Mutex Methods Object 5360 ** 5361 ** An instance of this structure defines the low-level routines 5362 ** used to allocate and use mutexes. 5363 ** 5364 ** Usually, the default mutex implementations provided by SQLite are 5365 ** sufficient, however the user has the option of substituting a custom 5366 ** implementation for specialized deployments or systems for which SQLite 5367 ** does not provide a suitable implementation. In this case, the user 5368 ** creates and populates an instance of this structure to pass 5369 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 5370 ** Additionally, an instance of this structure can be used as an 5371 ** output variable when querying the system for the current mutex 5372 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 5373 ** 5374 ** ^The xMutexInit method defined by this structure is invoked as 5375 ** part of system initialization by the sqlite3_initialize() function. 5376 ** ^The xMutexInit routine is called by SQLite exactly once for each 5377 ** effective call to [sqlite3_initialize()]. 5378 ** 5379 ** ^The xMutexEnd method defined by this structure is invoked as 5380 ** part of system shutdown by the sqlite3_shutdown() function. The 5381 ** implementation of this method is expected to release all outstanding 5382 ** resources obtained by the mutex methods implementation, especially 5383 ** those obtained by the xMutexInit method. ^The xMutexEnd() 5384 ** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 5385 ** 5386 ** ^(The remaining seven methods defined by this structure (xMutexAlloc, 5387 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 5388 ** xMutexNotheld) implement the following interfaces (respectively): 5389 ** 5390 ** <ul> 5391 ** <li> [sqlite3_mutex_alloc()] </li> 5392 ** <li> [sqlite3_mutex_free()] </li> 5393 ** <li> [sqlite3_mutex_enter()] </li> 5394 ** <li> [sqlite3_mutex_try()] </li> 5395 ** <li> [sqlite3_mutex_leave()] </li> 5396 ** <li> [sqlite3_mutex_held()] </li> 5397 ** <li> [sqlite3_mutex_notheld()] </li> 5398 ** </ul>)^ 5399 ** 5400 ** The only difference is that the public sqlite3_XXX functions enumerated 5401 ** above silently ignore any invocations that pass a NULL pointer instead 5402 ** of a valid mutex handle. The implementations of the methods defined 5403 ** by this structure are not required to handle this case, the results 5404 ** of passing a NULL pointer instead of a valid mutex handle are undefined 5405 ** (i.e. it is acceptable to provide an implementation that segfaults if 5406 ** it is passed a NULL pointer). 5407 ** 5408 ** The xMutexInit() method must be threadsafe. ^It must be harmless to 5409 ** invoke xMutexInit() multiple times within the same process and without 5410 ** intervening calls to xMutexEnd(). Second and subsequent calls to 5411 ** xMutexInit() must be no-ops. 5412 ** 5413 ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 5414 ** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 5415 ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 5416 ** memory allocation for a fast or recursive mutex. 5417 ** 5418 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 5419 ** called, but only if the prior call to xMutexInit returned SQLITE_OK. 5420 ** If xMutexInit fails in any way, it is expected to clean up after itself 5421 ** prior to returning. 5422 */ 5423 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 5424 struct sqlite3_mutex_methods { 5425 int (*xMutexInit)(void); 5426 int (*xMutexEnd)(void); 5427 sqlite3_mutex *(*xMutexAlloc)(int); 5428 void (*xMutexFree)(sqlite3_mutex *); 5429 void (*xMutexEnter)(sqlite3_mutex *); 5430 int (*xMutexTry)(sqlite3_mutex *); 5431 void (*xMutexLeave)(sqlite3_mutex *); 5432 int (*xMutexHeld)(sqlite3_mutex *); 5433 int (*xMutexNotheld)(sqlite3_mutex *); 5434 }; 5435 5436 /* 5437 ** CAPI3REF: Mutex Verification Routines 5438 ** 5439 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 5440 ** are intended for use inside assert() statements. ^The SQLite core 5441 ** never uses these routines except inside an assert() and applications 5442 ** are advised to follow the lead of the core. ^The SQLite core only 5443 ** provides implementations for these routines when it is compiled 5444 ** with the SQLITE_DEBUG flag. ^External mutex implementations 5445 ** are only required to provide these routines if SQLITE_DEBUG is 5446 ** defined and if NDEBUG is not defined. 5447 ** 5448 ** ^These routines should return true if the mutex in their argument 5449 ** is held or not held, respectively, by the calling thread. 5450 ** 5451 ** ^The implementation is not required to provided versions of these 5452 ** routines that actually work. If the implementation does not provide working 5453 ** versions of these routines, it should at least provide stubs that always 5454 ** return true so that one does not get spurious assertion failures. 5455 ** 5456 ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 5457 ** the routine should return 1. This seems counter-intuitive since 5458 ** clearly the mutex cannot be held if it does not exist. But 5459 ** the reason the mutex does not exist is because the build is not 5460 ** using mutexes. And we do not want the assert() containing the 5461 ** call to sqlite3_mutex_held() to fail, so a non-zero return is 5462 ** the appropriate thing to do. ^The sqlite3_mutex_notheld() 5463 ** interface should also return 1 when given a NULL pointer. 5464 */ 5465 #ifndef NDEBUG 5466 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*); 5467 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*); 5468 #endif 5469 5470 /* 5471 ** CAPI3REF: Mutex Types 5472 ** 5473 ** The [sqlite3_mutex_alloc()] interface takes a single argument 5474 ** which is one of these integer constants. 5475 ** 5476 ** The set of static mutexes may change from one SQLite release to the 5477 ** next. Applications that override the built-in mutex logic must be 5478 ** prepared to accommodate additional static mutexes. 5479 */ 5480 #define SQLITE_MUTEX_FAST 0 5481 #define SQLITE_MUTEX_RECURSIVE 1 5482 #define SQLITE_MUTEX_STATIC_MASTER 2 5483 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 5484 #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 5485 #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 5486 #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 5487 #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 5488 #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 5489 #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 5490 5491 /* 5492 ** CAPI3REF: Retrieve the mutex for a database connection 5493 ** 5494 ** ^This interface returns a pointer the [sqlite3_mutex] object that 5495 ** serializes access to the [database connection] given in the argument 5496 ** when the [threading mode] is Serialized. 5497 ** ^If the [threading mode] is Single-thread or Multi-thread then this 5498 ** routine returns a NULL pointer. 5499 */ 5500 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 5501 5502 /* 5503 ** CAPI3REF: Low-Level Control Of Database Files 5504 ** 5505 ** ^The [sqlite3_file_control()] interface makes a direct call to the 5506 ** xFileControl method for the [sqlite3_io_methods] object associated 5507 ** with a particular database identified by the second argument. ^The 5508 ** name of the database is "main" for the main database or "temp" for the 5509 ** TEMP database, or the name that appears after the AS keyword for 5510 ** databases that are added using the [ATTACH] SQL command. 5511 ** ^A NULL pointer can be used in place of "main" to refer to the 5512 ** main database file. 5513 ** ^The third and fourth parameters to this routine 5514 ** are passed directly through to the second and third parameters of 5515 ** the xFileControl method. ^The return value of the xFileControl 5516 ** method becomes the return value of this routine. 5517 ** 5518 ** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 5519 ** a pointer to the underlying [sqlite3_file] object to be written into 5520 ** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 5521 ** case is a short-circuit path which does not actually invoke the 5522 ** underlying sqlite3_io_methods.xFileControl method. 5523 ** 5524 ** ^If the second parameter (zDbName) does not match the name of any 5525 ** open database file, then SQLITE_ERROR is returned. ^This error 5526 ** code is not remembered and will not be recalled by [sqlite3_errcode()] 5527 ** or [sqlite3_errmsg()]. The underlying xFileControl method might 5528 ** also return SQLITE_ERROR. There is no way to distinguish between 5529 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5530 ** xFileControl method. 5531 ** 5532 ** See also: [SQLITE_FCNTL_LOCKSTATE] 5533 */ 5534 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5535 5536 /* 5537 ** CAPI3REF: Testing Interface 5538 ** 5539 ** ^The sqlite3_test_control() interface is used to read out internal 5540 ** state of SQLite and to inject faults into SQLite for testing 5541 ** purposes. ^The first parameter is an operation code that determines 5542 ** the number, meaning, and operation of all subsequent parameters. 5543 ** 5544 ** This interface is not for use by applications. It exists solely 5545 ** for verifying the correct operation of the SQLite library. Depending 5546 ** on how the SQLite library is compiled, this interface might not exist. 5547 ** 5548 ** The details of the operation codes, their meanings, the parameters 5549 ** they take, and what they do are all subject to change without notice. 5550 ** Unlike most of the SQLite API, this function is not guaranteed to 5551 ** operate consistently from one release to the next. 5552 */ 5553 SQLITE_API int sqlite3_test_control(int op, ...); 5554 5555 /* 5556 ** CAPI3REF: Testing Interface Operation Codes 5557 ** 5558 ** These constants are the valid operation code parameters used 5559 ** as the first argument to [sqlite3_test_control()]. 5560 ** 5561 ** These parameters and their meanings are subject to change 5562 ** without notice. These values are for testing purposes only. 5563 ** Applications should not use any of these parameters or the 5564 ** [sqlite3_test_control()] interface. 5565 */ 5566 #define SQLITE_TESTCTRL_FIRST 5 5567 #define SQLITE_TESTCTRL_PRNG_SAVE 5 5568 #define SQLITE_TESTCTRL_PRNG_RESTORE 6 5569 #define SQLITE_TESTCTRL_PRNG_RESET 7 5570 #define SQLITE_TESTCTRL_BITVEC_TEST 8 5571 #define SQLITE_TESTCTRL_FAULT_INSTALL 9 5572 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5573 #define SQLITE_TESTCTRL_PENDING_BYTE 11 5574 #define SQLITE_TESTCTRL_ASSERT 12 5575 #define SQLITE_TESTCTRL_ALWAYS 13 5576 #define SQLITE_TESTCTRL_RESERVE 14 5577 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15 5578 #define SQLITE_TESTCTRL_ISKEYWORD 16 5579 #define SQLITE_TESTCTRL_PGHDRSZ 17 5580 #define SQLITE_TESTCTRL_SCRATCHMALLOC 18 5581 #define SQLITE_TESTCTRL_LOCALTIME_FAULT 19 5582 #define SQLITE_TESTCTRL_LAST 19 5583 5584 /* 5585 ** CAPI3REF: SQLite Runtime Status 5586 ** 5587 ** ^This interface is used to retrieve runtime status information 5588 ** about the performance of SQLite, and optionally to reset various 5589 ** highwater marks. ^The first argument is an integer code for 5590 ** the specific parameter to measure. ^(Recognized integer codes 5591 ** are of the form [status parameters | SQLITE_STATUS_...].)^ 5592 ** ^The current value of the parameter is returned into *pCurrent. 5593 ** ^The highest recorded value is returned in *pHighwater. ^If the 5594 ** resetFlag is true, then the highest record value is reset after 5595 ** *pHighwater is written. ^(Some parameters do not record the highest 5596 ** value. For those parameters 5597 ** nothing is written into *pHighwater and the resetFlag is ignored.)^ 5598 ** ^(Other parameters record only the highwater mark and not the current 5599 ** value. For these latter parameters nothing is written into *pCurrent.)^ 5600 ** 5601 ** ^The sqlite3_status() routine returns SQLITE_OK on success and a 5602 ** non-zero [error code] on failure. 5603 ** 5604 ** This routine is threadsafe but is not atomic. This routine can be 5605 ** called while other threads are running the same or different SQLite 5606 ** interfaces. However the values returned in *pCurrent and 5607 ** *pHighwater reflect the status of SQLite at different points in time 5608 ** and it is possible that another thread might change the parameter 5609 ** in between the times when *pCurrent and *pHighwater are written. 5610 ** 5611 ** See also: [sqlite3_db_status()] 5612 */ 5613 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 5614 5615 5616 /* 5617 ** CAPI3REF: Status Parameters 5618 ** KEYWORDS: {status parameters} 5619 ** 5620 ** These integer constants designate various run-time status parameters 5621 ** that can be returned by [sqlite3_status()]. 5622 ** 5623 ** <dl> 5624 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 5625 ** <dd>This parameter is the current amount of memory checked out 5626 ** using [sqlite3_malloc()], either directly or indirectly. The 5627 ** figure includes calls made to [sqlite3_malloc()] by the application 5628 ** and internal memory usage by the SQLite library. Scratch memory 5629 ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 5630 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 5631 ** this parameter. The amount returned is the sum of the allocation 5632 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 5633 ** 5634 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 5635 ** <dd>This parameter records the largest memory allocation request 5636 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 5637 ** internal equivalents). Only the value returned in the 5638 ** *pHighwater parameter to [sqlite3_status()] is of interest. 5639 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 5640 ** 5641 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 5642 ** <dd>This parameter records the number of separate memory allocations 5643 ** currently checked out.</dd>)^ 5644 ** 5645 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 5646 ** <dd>This parameter returns the number of pages used out of the 5647 ** [pagecache memory allocator] that was configured using 5648 ** [SQLITE_CONFIG_PAGECACHE]. The 5649 ** value returned is in pages, not in bytes.</dd>)^ 5650 ** 5651 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 5652 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5653 ** <dd>This parameter returns the number of bytes of page cache 5654 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 5655 ** buffer and where forced to overflow to [sqlite3_malloc()]. The 5656 ** returned value includes allocations that overflowed because they 5657 ** where too large (they were larger than the "sz" parameter to 5658 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 5659 ** no space was left in the page cache.</dd>)^ 5660 ** 5661 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 5662 ** <dd>This parameter records the largest memory allocation request 5663 ** handed to [pagecache memory allocator]. Only the value returned in the 5664 ** *pHighwater parameter to [sqlite3_status()] is of interest. 5665 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 5666 ** 5667 ** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 5668 ** <dd>This parameter returns the number of allocations used out of the 5669 ** [scratch memory allocator] configured using 5670 ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5671 ** in bytes. Since a single thread may only have one scratch allocation 5672 ** outstanding at time, this parameter also reports the number of threads 5673 ** using scratch memory at the same time.</dd>)^ 5674 ** 5675 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5676 ** <dd>This parameter returns the number of bytes of scratch memory 5677 ** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 5678 ** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5679 ** returned include overflows because the requested allocation was too 5680 ** larger (that is, because the requested allocation was larger than the 5681 ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5682 ** slots were available. 5683 ** </dd>)^ 5684 ** 5685 ** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5686 ** <dd>This parameter records the largest memory allocation request 5687 ** handed to [scratch memory allocator]. Only the value returned in the 5688 ** *pHighwater parameter to [sqlite3_status()] is of interest. 5689 ** The value written into the *pCurrent parameter is undefined.</dd>)^ 5690 ** 5691 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 5692 ** <dd>This parameter records the deepest parser stack. It is only 5693 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 5694 ** </dl> 5695 ** 5696 ** New status parameters may be added from time to time. 5697 */ 5698 #define SQLITE_STATUS_MEMORY_USED 0 5699 #define SQLITE_STATUS_PAGECACHE_USED 1 5700 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5701 #define SQLITE_STATUS_SCRATCH_USED 3 5702 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5703 #define SQLITE_STATUS_MALLOC_SIZE 5 5704 #define SQLITE_STATUS_PARSER_STACK 6 5705 #define SQLITE_STATUS_PAGECACHE_SIZE 7 5706 #define SQLITE_STATUS_SCRATCH_SIZE 8 5707 #define SQLITE_STATUS_MALLOC_COUNT 9 5708 5709 /* 5710 ** CAPI3REF: Database Connection Status 5711 ** 5712 ** ^This interface is used to retrieve runtime status information 5713 ** about a single [database connection]. ^The first argument is the 5714 ** database connection object to be interrogated. ^The second argument 5715 ** is an integer constant, taken from the set of 5716 ** [SQLITE_DBSTATUS options], that 5717 ** determines the parameter to interrogate. The set of 5718 ** [SQLITE_DBSTATUS options] is likely 5719 ** to grow in future releases of SQLite. 5720 ** 5721 ** ^The current value of the requested parameter is written into *pCur 5722 ** and the highest instantaneous value is written into *pHiwtr. ^If 5723 ** the resetFlg is true, then the highest instantaneous value is 5724 ** reset back down to the current value. 5725 ** 5726 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 5727 ** non-zero [error code] on failure. 5728 ** 5729 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5730 */ 5731 SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5732 5733 /* 5734 ** CAPI3REF: Status Parameters for database connections 5735 ** KEYWORDS: {SQLITE_DBSTATUS options} 5736 ** 5737 ** These constants are the available integer "verbs" that can be passed as 5738 ** the second argument to the [sqlite3_db_status()] interface. 5739 ** 5740 ** New verbs may be added in future releases of SQLite. Existing verbs 5741 ** might be discontinued. Applications should check the return code from 5742 ** [sqlite3_db_status()] to make sure that the call worked. 5743 ** The [sqlite3_db_status()] interface will return a non-zero error code 5744 ** if a discontinued or unsupported verb is invoked. 5745 ** 5746 ** <dl> 5747 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5748 ** <dd>This parameter returns the number of lookaside memory slots currently 5749 ** checked out.</dd>)^ 5750 ** 5751 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 5752 ** <dd>This parameter returns the number malloc attempts that were 5753 ** satisfied using lookaside memory. Only the high-water value is meaningful; 5754 ** the current value is always zero.)^ 5755 ** 5756 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 5757 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 5758 ** <dd>This parameter returns the number malloc attempts that might have 5759 ** been satisfied using lookaside memory but failed due to the amount of 5760 ** memory requested being larger than the lookaside slot size. 5761 ** Only the high-water value is meaningful; 5762 ** the current value is always zero.)^ 5763 ** 5764 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 5765 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 5766 ** <dd>This parameter returns the number malloc attempts that might have 5767 ** been satisfied using lookaside memory but failed due to all lookaside 5768 ** memory already being in use. 5769 ** Only the high-water value is meaningful; 5770 ** the current value is always zero.)^ 5771 ** 5772 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 5773 ** <dd>This parameter returns the approximate number of of bytes of heap 5774 ** memory used by all pager caches associated with the database connection.)^ 5775 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 5776 ** 5777 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 5778 ** <dd>This parameter returns the approximate number of of bytes of heap 5779 ** memory used to store the schema for all databases associated 5780 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 5781 ** ^The full amount of memory used by the schemas is reported, even if the 5782 ** schema memory is shared with other database connections due to 5783 ** [shared cache mode] being enabled. 5784 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 5785 ** 5786 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 5787 ** <dd>This parameter returns the approximate number of of bytes of heap 5788 ** and lookaside memory used by all prepared statements associated with 5789 ** the database connection.)^ 5790 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 5791 ** </dd> 5792 ** </dl> 5793 */ 5794 #define SQLITE_DBSTATUS_LOOKASIDE_USED 0 5795 #define SQLITE_DBSTATUS_CACHE_USED 1 5796 #define SQLITE_DBSTATUS_SCHEMA_USED 2 5797 #define SQLITE_DBSTATUS_STMT_USED 3 5798 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 5799 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 5800 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 5801 #define SQLITE_DBSTATUS_MAX 6 /* Largest defined DBSTATUS */ 5802 5803 5804 /* 5805 ** CAPI3REF: Prepared Statement Status 5806 ** 5807 ** ^(Each prepared statement maintains various 5808 ** [SQLITE_STMTSTATUS counters] that measure the number 5809 ** of times it has performed specific operations.)^ These counters can 5810 ** be used to monitor the performance characteristics of the prepared 5811 ** statements. For example, if the number of table steps greatly exceeds 5812 ** the number of table searches or result rows, that would tend to indicate 5813 ** that the prepared statement is using a full table scan rather than 5814 ** an index. 5815 ** 5816 ** ^(This interface is used to retrieve and reset counter values from 5817 ** a [prepared statement]. The first argument is the prepared statement 5818 ** object to be interrogated. The second argument 5819 ** is an integer code for a specific [SQLITE_STMTSTATUS counter] 5820 ** to be interrogated.)^ 5821 ** ^The current value of the requested counter is returned. 5822 ** ^If the resetFlg is true, then the counter is reset to zero after this 5823 ** interface call returns. 5824 ** 5825 ** See also: [sqlite3_status()] and [sqlite3_db_status()]. 5826 */ 5827 SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 5828 5829 /* 5830 ** CAPI3REF: Status Parameters for prepared statements 5831 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 5832 ** 5833 ** These preprocessor macros define integer codes that name counter 5834 ** values associated with the [sqlite3_stmt_status()] interface. 5835 ** The meanings of the various counters are as follows: 5836 ** 5837 ** <dl> 5838 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 5839 ** <dd>^This is the number of times that SQLite has stepped forward in 5840 ** a table as part of a full table scan. Large numbers for this counter 5841 ** may indicate opportunities for performance improvement through 5842 ** careful use of indices.</dd> 5843 ** 5844 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 5845 ** <dd>^This is the number of sort operations that have occurred. 5846 ** A non-zero value in this counter may indicate an opportunity to 5847 ** improvement performance through careful use of indices.</dd> 5848 ** 5849 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 5850 ** <dd>^This is the number of rows inserted into transient indices that 5851 ** were created automatically in order to help joins run faster. 5852 ** A non-zero value in this counter may indicate an opportunity to 5853 ** improvement performance by adding permanent indices that do not 5854 ** need to be reinitialized each time the statement is run.</dd> 5855 ** 5856 ** </dl> 5857 */ 5858 #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 5859 #define SQLITE_STMTSTATUS_SORT 2 5860 #define SQLITE_STMTSTATUS_AUTOINDEX 3 5861 5862 /* 5863 ** CAPI3REF: Custom Page Cache Object 5864 ** 5865 ** The sqlite3_pcache type is opaque. It is implemented by 5866 ** the pluggable module. The SQLite core has no knowledge of 5867 ** its size or internal structure and never deals with the 5868 ** sqlite3_pcache object except by holding and passing pointers 5869 ** to the object. 5870 ** 5871 ** See [sqlite3_pcache_methods] for additional information. 5872 */ 5873 typedef struct sqlite3_pcache sqlite3_pcache; 5874 5875 /* 5876 ** CAPI3REF: Application Defined Page Cache. 5877 ** KEYWORDS: {page cache} 5878 ** 5879 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can 5880 ** register an alternative page cache implementation by passing in an 5881 ** instance of the sqlite3_pcache_methods structure.)^ 5882 ** In many applications, most of the heap memory allocated by 5883 ** SQLite is used for the page cache. 5884 ** By implementing a 5885 ** custom page cache using this API, an application can better control 5886 ** the amount of memory consumed by SQLite, the way in which 5887 ** that memory is allocated and released, and the policies used to 5888 ** determine exactly which parts of a database file are cached and for 5889 ** how long. 5890 ** 5891 ** The alternative page cache mechanism is an 5892 ** extreme measure that is only needed by the most demanding applications. 5893 ** The built-in page cache is recommended for most uses. 5894 ** 5895 ** ^(The contents of the sqlite3_pcache_methods structure are copied to an 5896 ** internal buffer by SQLite within the call to [sqlite3_config]. Hence 5897 ** the application may discard the parameter after the call to 5898 ** [sqlite3_config()] returns.)^ 5899 ** 5900 ** [[the xInit() page cache method]] 5901 ** ^(The xInit() method is called once for each effective 5902 ** call to [sqlite3_initialize()])^ 5903 ** (usually only once during the lifetime of the process). ^(The xInit() 5904 ** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^ 5905 ** The intent of the xInit() method is to set up global data structures 5906 ** required by the custom page cache implementation. 5907 ** ^(If the xInit() method is NULL, then the 5908 ** built-in default page cache is used instead of the application defined 5909 ** page cache.)^ 5910 ** 5911 ** [[the xShutdown() page cache method]] 5912 ** ^The xShutdown() method is called by [sqlite3_shutdown()]. 5913 ** It can be used to clean up 5914 ** any outstanding resources before process shutdown, if required. 5915 ** ^The xShutdown() method may be NULL. 5916 ** 5917 ** ^SQLite automatically serializes calls to the xInit method, 5918 ** so the xInit method need not be threadsafe. ^The 5919 ** xShutdown method is only called from [sqlite3_shutdown()] so it does 5920 ** not need to be threadsafe either. All other methods must be threadsafe 5921 ** in multithreaded applications. 5922 ** 5923 ** ^SQLite will never invoke xInit() more than once without an intervening 5924 ** call to xShutdown(). 5925 ** 5926 ** [[the xCreate() page cache methods]] 5927 ** ^SQLite invokes the xCreate() method to construct a new cache instance. 5928 ** SQLite will typically create one cache instance for each open database file, 5929 ** though this is not guaranteed. ^The 5930 ** first parameter, szPage, is the size in bytes of the pages that must 5931 ** be allocated by the cache. ^szPage will not be a power of two. ^szPage 5932 ** will the page size of the database file that is to be cached plus an 5933 ** increment (here called "R") of less than 250. SQLite will use the 5934 ** extra R bytes on each page to store metadata about the underlying 5935 ** database page on disk. The value of R depends 5936 ** on the SQLite version, the target platform, and how SQLite was compiled. 5937 ** ^(R is constant for a particular build of SQLite. Except, there are two 5938 ** distinct values of R when SQLite is compiled with the proprietary 5939 ** ZIPVFS extension.)^ ^The second argument to 5940 ** xCreate(), bPurgeable, is true if the cache being created will 5941 ** be used to cache database pages of a file stored on disk, or 5942 ** false if it is used for an in-memory database. The cache implementation 5943 ** does not have to do anything special based with the value of bPurgeable; 5944 ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 5945 ** never invoke xUnpin() except to deliberately delete a page. 5946 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 5947 ** false will always have the "discard" flag set to true. 5948 ** ^Hence, a cache created with bPurgeable false will 5949 ** never contain any unpinned pages. 5950 ** 5951 ** [[the xCachesize() page cache method]] 5952 ** ^(The xCachesize() method may be called at any time by SQLite to set the 5953 ** suggested maximum cache-size (number of pages stored by) the cache 5954 ** instance passed as the first argument. This is the value configured using 5955 ** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 5956 ** parameter, the implementation is not required to do anything with this 5957 ** value; it is advisory only. 5958 ** 5959 ** [[the xPagecount() page cache methods]] 5960 ** The xPagecount() method must return the number of pages currently 5961 ** stored in the cache, both pinned and unpinned. 5962 ** 5963 ** [[the xFetch() page cache methods]] 5964 ** The xFetch() method locates a page in the cache and returns a pointer to 5965 ** the page, or a NULL pointer. 5966 ** A "page", in this context, means a buffer of szPage bytes aligned at an 5967 ** 8-byte boundary. The page to be fetched is determined by the key. ^The 5968 ** minimum key value is 1. After it has been retrieved using xFetch, the page 5969 ** is considered to be "pinned". 5970 ** 5971 ** If the requested page is already in the page cache, then the page cache 5972 ** implementation must return a pointer to the page buffer with its content 5973 ** intact. If the requested page is not already in the cache, then the 5974 ** cache implementation should use the value of the createFlag 5975 ** parameter to help it determined what action to take: 5976 ** 5977 ** <table border=1 width=85% align=center> 5978 ** <tr><th> createFlag <th> Behaviour when page is not already in cache 5979 ** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 5980 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 5981 ** Otherwise return NULL. 5982 ** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 5983 ** NULL if allocating a new page is effectively impossible. 5984 ** </table> 5985 ** 5986 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 5987 ** will only use a createFlag of 2 after a prior call with a createFlag of 1 5988 ** failed.)^ In between the to xFetch() calls, SQLite may 5989 ** attempt to unpin one or more cache pages by spilling the content of 5990 ** pinned pages to disk and synching the operating system disk cache. 5991 ** 5992 ** [[the xUnpin() page cache method]] 5993 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 5994 ** as its second argument. If the third parameter, discard, is non-zero, 5995 ** then the page must be evicted from the cache. 5996 ** ^If the discard parameter is 5997 ** zero, then the page may be discarded or retained at the discretion of 5998 ** page cache implementation. ^The page cache implementation 5999 ** may choose to evict unpinned pages at any time. 6000 ** 6001 ** The cache must not perform any reference counting. A single 6002 ** call to xUnpin() unpins the page regardless of the number of prior calls 6003 ** to xFetch(). 6004 ** 6005 ** [[the xRekey() page cache methods]] 6006 ** The xRekey() method is used to change the key value associated with the 6007 ** page passed as the second argument. If the cache 6008 ** previously contains an entry associated with newKey, it must be 6009 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6010 ** to be pinned. 6011 ** 6012 ** When SQLite calls the xTruncate() method, the cache must discard all 6013 ** existing cache entries with page numbers (keys) greater than or equal 6014 ** to the value of the iLimit parameter passed to xTruncate(). If any 6015 ** of these pages are pinned, they are implicitly unpinned, meaning that 6016 ** they can be safely discarded. 6017 ** 6018 ** [[the xDestroy() page cache method]] 6019 ** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6020 ** All resources associated with the specified cache should be freed. ^After 6021 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6022 ** handle invalid, and will not use it with any other sqlite3_pcache_methods 6023 ** functions. 6024 */ 6025 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 6026 struct sqlite3_pcache_methods { 6027 void *pArg; 6028 int (*xInit)(void*); 6029 void (*xShutdown)(void*); 6030 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 6031 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6032 int (*xPagecount)(sqlite3_pcache*); 6033 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6034 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 6035 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 6036 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6037 void (*xDestroy)(sqlite3_pcache*); 6038 }; 6039 6040 /* 6041 ** CAPI3REF: Online Backup Object 6042 ** 6043 ** The sqlite3_backup object records state information about an ongoing 6044 ** online backup operation. ^The sqlite3_backup object is created by 6045 ** a call to [sqlite3_backup_init()] and is destroyed by a call to 6046 ** [sqlite3_backup_finish()]. 6047 ** 6048 ** See Also: [Using the SQLite Online Backup API] 6049 */ 6050 typedef struct sqlite3_backup sqlite3_backup; 6051 6052 /* 6053 ** CAPI3REF: Online Backup API. 6054 ** 6055 ** The backup API copies the content of one database into another. 6056 ** It is useful either for creating backups of databases or 6057 ** for copying in-memory databases to or from persistent files. 6058 ** 6059 ** See Also: [Using the SQLite Online Backup API] 6060 ** 6061 ** ^SQLite holds a write transaction open on the destination database file 6062 ** for the duration of the backup operation. 6063 ** ^The source database is read-locked only while it is being read; 6064 ** it is not locked continuously for the entire backup operation. 6065 ** ^Thus, the backup may be performed on a live source database without 6066 ** preventing other database connections from 6067 ** reading or writing to the source database while the backup is underway. 6068 ** 6069 ** ^(To perform a backup operation: 6070 ** <ol> 6071 ** <li><b>sqlite3_backup_init()</b> is called once to initialize the 6072 ** backup, 6073 ** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 6074 ** the data between the two databases, and finally 6075 ** <li><b>sqlite3_backup_finish()</b> is called to release all resources 6076 ** associated with the backup operation. 6077 ** </ol>)^ 6078 ** There should be exactly one call to sqlite3_backup_finish() for each 6079 ** successful call to sqlite3_backup_init(). 6080 ** 6081 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 6082 ** 6083 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 6084 ** [database connection] associated with the destination database 6085 ** and the database name, respectively. 6086 ** ^The database name is "main" for the main database, "temp" for the 6087 ** temporary database, or the name specified after the AS keyword in 6088 ** an [ATTACH] statement for an attached database. 6089 ** ^The S and M arguments passed to 6090 ** sqlite3_backup_init(D,N,S,M) identify the [database connection] 6091 ** and database name of the source database, respectively. 6092 ** ^The source and destination [database connections] (parameters S and D) 6093 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 6094 ** an error. 6095 ** 6096 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 6097 ** returned and an error code and error message are stored in the 6098 ** destination [database connection] D. 6099 ** ^The error code and message for the failed call to sqlite3_backup_init() 6100 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 6101 ** [sqlite3_errmsg16()] functions. 6102 ** ^A successful call to sqlite3_backup_init() returns a pointer to an 6103 ** [sqlite3_backup] object. 6104 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 6105 ** sqlite3_backup_finish() functions to perform the specified backup 6106 ** operation. 6107 ** 6108 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 6109 ** 6110 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 6111 ** the source and destination databases specified by [sqlite3_backup] object B. 6112 ** ^If N is negative, all remaining source pages are copied. 6113 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 6114 ** are still more pages to be copied, then the function returns [SQLITE_OK]. 6115 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 6116 ** from source to destination, then it returns [SQLITE_DONE]. 6117 ** ^If an error occurs while running sqlite3_backup_step(B,N), 6118 ** then an [error code] is returned. ^As well as [SQLITE_OK] and 6119 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 6120 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 6121 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 6122 ** 6123 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 6124 ** <ol> 6125 ** <li> the destination database was opened read-only, or 6126 ** <li> the destination database is using write-ahead-log journaling 6127 ** and the destination and source page sizes differ, or 6128 ** <li> the destination database is an in-memory database and the 6129 ** destination and source page sizes differ. 6130 ** </ol>)^ 6131 ** 6132 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 6133 ** the [sqlite3_busy_handler | busy-handler function] 6134 ** is invoked (if one is specified). ^If the 6135 ** busy-handler returns non-zero before the lock is available, then 6136 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 6137 ** sqlite3_backup_step() can be retried later. ^If the source 6138 ** [database connection] 6139 ** is being used to write to the source database when sqlite3_backup_step() 6140 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 6141 ** case the call to sqlite3_backup_step() can be retried later on. ^(If 6142 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 6143 ** [SQLITE_READONLY] is returned, then 6144 ** there is no point in retrying the call to sqlite3_backup_step(). These 6145 ** errors are considered fatal.)^ The application must accept 6146 ** that the backup operation has failed and pass the backup operation handle 6147 ** to the sqlite3_backup_finish() to release associated resources. 6148 ** 6149 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock 6150 ** on the destination file. ^The exclusive lock is not released until either 6151 ** sqlite3_backup_finish() is called or the backup operation is complete 6152 ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 6153 ** sqlite3_backup_step() obtains a [shared lock] on the source database that 6154 ** lasts for the duration of the sqlite3_backup_step() call. 6155 ** ^Because the source database is not locked between calls to 6156 ** sqlite3_backup_step(), the source database may be modified mid-way 6157 ** through the backup process. ^If the source database is modified by an 6158 ** external process or via a database connection other than the one being 6159 ** used by the backup operation, then the backup will be automatically 6160 ** restarted by the next call to sqlite3_backup_step(). ^If the source 6161 ** database is modified by the using the same database connection as is used 6162 ** by the backup operation, then the backup database is automatically 6163 ** updated at the same time. 6164 ** 6165 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 6166 ** 6167 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 6168 ** application wishes to abandon the backup operation, the application 6169 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 6170 ** ^The sqlite3_backup_finish() interfaces releases all 6171 ** resources associated with the [sqlite3_backup] object. 6172 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 6173 ** active write-transaction on the destination database is rolled back. 6174 ** The [sqlite3_backup] object is invalid 6175 ** and may not be used following a call to sqlite3_backup_finish(). 6176 ** 6177 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 6178 ** sqlite3_backup_step() errors occurred, regardless or whether or not 6179 ** sqlite3_backup_step() completed. 6180 ** ^If an out-of-memory condition or IO error occurred during any prior 6181 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 6182 ** sqlite3_backup_finish() returns the corresponding [error code]. 6183 ** 6184 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 6185 ** is not a permanent error and does not affect the return value of 6186 ** sqlite3_backup_finish(). 6187 ** 6188 ** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]] 6189 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 6190 ** 6191 ** ^Each call to sqlite3_backup_step() sets two values inside 6192 ** the [sqlite3_backup] object: the number of pages still to be backed 6193 ** up and the total number of pages in the source database file. 6194 ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 6195 ** retrieve these two values, respectively. 6196 ** 6197 ** ^The values returned by these functions are only updated by 6198 ** sqlite3_backup_step(). ^If the source database is modified during a backup 6199 ** operation, then the values are not updated to account for any extra 6200 ** pages that need to be updated or the size of the source database file 6201 ** changing. 6202 ** 6203 ** <b>Concurrent Usage of Database Handles</b> 6204 ** 6205 ** ^The source [database connection] may be used by the application for other 6206 ** purposes while a backup operation is underway or being initialized. 6207 ** ^If SQLite is compiled and configured to support threadsafe database 6208 ** connections, then the source database connection may be used concurrently 6209 ** from within other threads. 6210 ** 6211 ** However, the application must guarantee that the destination 6212 ** [database connection] is not passed to any other API (by any thread) after 6213 ** sqlite3_backup_init() is called and before the corresponding call to 6214 ** sqlite3_backup_finish(). SQLite does not currently check to see 6215 ** if the application incorrectly accesses the destination [database connection] 6216 ** and so no error code is reported, but the operations may malfunction 6217 ** nevertheless. Use of the destination database connection while a 6218 ** backup is in progress might also also cause a mutex deadlock. 6219 ** 6220 ** If running in [shared cache mode], the application must 6221 ** guarantee that the shared cache used by the destination database 6222 ** is not accessed while the backup is running. In practice this means 6223 ** that the application must guarantee that the disk file being 6224 ** backed up to is not accessed by any connection within the process, 6225 ** not just the specific connection that was passed to sqlite3_backup_init(). 6226 ** 6227 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple 6228 ** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 6229 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 6230 ** APIs are not strictly speaking threadsafe. If they are invoked at the 6231 ** same time as another thread is invoking sqlite3_backup_step() it is 6232 ** possible that they return invalid values. 6233 */ 6234 SQLITE_API sqlite3_backup *sqlite3_backup_init( 6235 sqlite3 *pDest, /* Destination database handle */ 6236 const char *zDestName, /* Destination database name */ 6237 sqlite3 *pSource, /* Source database handle */ 6238 const char *zSourceName /* Source database name */ 6239 ); 6240 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage); 6241 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p); 6242 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p); 6243 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p); 6244 6245 /* 6246 ** CAPI3REF: Unlock Notification 6247 ** 6248 ** ^When running in shared-cache mode, a database operation may fail with 6249 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 6250 ** individual tables within the shared-cache cannot be obtained. See 6251 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 6252 ** ^This API may be used to register a callback that SQLite will invoke 6253 ** when the connection currently holding the required lock relinquishes it. 6254 ** ^This API is only available if the library was compiled with the 6255 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 6256 ** 6257 ** See Also: [Using the SQLite Unlock Notification Feature]. 6258 ** 6259 ** ^Shared-cache locks are released when a database connection concludes 6260 ** its current transaction, either by committing it or rolling it back. 6261 ** 6262 ** ^When a connection (known as the blocked connection) fails to obtain a 6263 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 6264 ** identity of the database connection (the blocking connection) that 6265 ** has locked the required resource is stored internally. ^After an 6266 ** application receives an SQLITE_LOCKED error, it may call the 6267 ** sqlite3_unlock_notify() method with the blocked connection handle as 6268 ** the first argument to register for a callback that will be invoked 6269 ** when the blocking connections current transaction is concluded. ^The 6270 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 6271 ** call that concludes the blocking connections transaction. 6272 ** 6273 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 6274 ** there is a chance that the blocking connection will have already 6275 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 6276 ** If this happens, then the specified callback is invoked immediately, 6277 ** from within the call to sqlite3_unlock_notify().)^ 6278 ** 6279 ** ^If the blocked connection is attempting to obtain a write-lock on a 6280 ** shared-cache table, and more than one other connection currently holds 6281 ** a read-lock on the same table, then SQLite arbitrarily selects one of 6282 ** the other connections to use as the blocking connection. 6283 ** 6284 ** ^(There may be at most one unlock-notify callback registered by a 6285 ** blocked connection. If sqlite3_unlock_notify() is called when the 6286 ** blocked connection already has a registered unlock-notify callback, 6287 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 6288 ** called with a NULL pointer as its second argument, then any existing 6289 ** unlock-notify callback is canceled. ^The blocked connections 6290 ** unlock-notify callback may also be canceled by closing the blocked 6291 ** connection using [sqlite3_close()]. 6292 ** 6293 ** The unlock-notify callback is not reentrant. If an application invokes 6294 ** any sqlite3_xxx API functions from within an unlock-notify callback, a 6295 ** crash or deadlock may be the result. 6296 ** 6297 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 6298 ** returns SQLITE_OK. 6299 ** 6300 ** <b>Callback Invocation Details</b> 6301 ** 6302 ** When an unlock-notify callback is registered, the application provides a 6303 ** single void* pointer that is passed to the callback when it is invoked. 6304 ** However, the signature of the callback function allows SQLite to pass 6305 ** it an array of void* context pointers. The first argument passed to 6306 ** an unlock-notify callback is a pointer to an array of void* pointers, 6307 ** and the second is the number of entries in the array. 6308 ** 6309 ** When a blocking connections transaction is concluded, there may be 6310 ** more than one blocked connection that has registered for an unlock-notify 6311 ** callback. ^If two or more such blocked connections have specified the 6312 ** same callback function, then instead of invoking the callback function 6313 ** multiple times, it is invoked once with the set of void* context pointers 6314 ** specified by the blocked connections bundled together into an array. 6315 ** This gives the application an opportunity to prioritize any actions 6316 ** related to the set of unblocked database connections. 6317 ** 6318 ** <b>Deadlock Detection</b> 6319 ** 6320 ** Assuming that after registering for an unlock-notify callback a 6321 ** database waits for the callback to be issued before taking any further 6322 ** action (a reasonable assumption), then using this API may cause the 6323 ** application to deadlock. For example, if connection X is waiting for 6324 ** connection Y's transaction to be concluded, and similarly connection 6325 ** Y is waiting on connection X's transaction, then neither connection 6326 ** will proceed and the system may remain deadlocked indefinitely. 6327 ** 6328 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 6329 ** detection. ^If a given call to sqlite3_unlock_notify() would put the 6330 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no 6331 ** unlock-notify callback is registered. The system is said to be in 6332 ** a deadlocked state if connection A has registered for an unlock-notify 6333 ** callback on the conclusion of connection B's transaction, and connection 6334 ** B has itself registered for an unlock-notify callback when connection 6335 ** A's transaction is concluded. ^Indirect deadlock is also detected, so 6336 ** the system is also considered to be deadlocked if connection B has 6337 ** registered for an unlock-notify callback on the conclusion of connection 6338 ** C's transaction, where connection C is waiting on connection A. ^Any 6339 ** number of levels of indirection are allowed. 6340 ** 6341 ** <b>The "DROP TABLE" Exception</b> 6342 ** 6343 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 6344 ** always appropriate to call sqlite3_unlock_notify(). There is however, 6345 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 6346 ** SQLite checks if there are any currently executing SELECT statements 6347 ** that belong to the same connection. If there are, SQLITE_LOCKED is 6348 ** returned. In this case there is no "blocking connection", so invoking 6349 ** sqlite3_unlock_notify() results in the unlock-notify callback being 6350 ** invoked immediately. If the application then re-attempts the "DROP TABLE" 6351 ** or "DROP INDEX" query, an infinite loop might be the result. 6352 ** 6353 ** One way around this problem is to check the extended error code returned 6354 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the 6355 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 6356 ** the special "DROP TABLE/INDEX" case, the extended error code is just 6357 ** SQLITE_LOCKED.)^ 6358 */ 6359 SQLITE_API int sqlite3_unlock_notify( 6360 sqlite3 *pBlocked, /* Waiting connection */ 6361 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 6362 void *pNotifyArg /* Argument to pass to xNotify */ 6363 ); 6364 6365 6366 /* 6367 ** CAPI3REF: String Comparison 6368 ** 6369 ** ^The [sqlite3_strnicmp()] API allows applications and extensions to 6370 ** compare the contents of two buffers containing UTF-8 strings in a 6371 ** case-independent fashion, using the same definition of case independence 6372 ** that SQLite uses internally when comparing identifiers. 6373 */ 6374 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int); 6375 6376 /* 6377 ** CAPI3REF: Error Logging Interface 6378 ** 6379 ** ^The [sqlite3_log()] interface writes a message into the error log 6380 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 6381 ** ^If logging is enabled, the zFormat string and subsequent arguments are 6382 ** used with [sqlite3_snprintf()] to generate the final output string. 6383 ** 6384 ** The sqlite3_log() interface is intended for use by extensions such as 6385 ** virtual tables, collating functions, and SQL functions. While there is 6386 ** nothing to prevent an application from calling sqlite3_log(), doing so 6387 ** is considered bad form. 6388 ** 6389 ** The zFormat string must not be NULL. 6390 ** 6391 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine 6392 ** will not use dynamically allocated memory. The log message is stored in 6393 ** a fixed-length buffer on the stack. If the log message is longer than 6394 ** a few hundred characters, it will be truncated to the length of the 6395 ** buffer. 6396 */ 6397 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...); 6398 6399 /* 6400 ** CAPI3REF: Write-Ahead Log Commit Hook 6401 ** 6402 ** ^The [sqlite3_wal_hook()] function is used to register a callback that 6403 ** will be invoked each time a database connection commits data to a 6404 ** [write-ahead log] (i.e. whenever a transaction is committed in 6405 ** [journal_mode | journal_mode=WAL mode]). 6406 ** 6407 ** ^The callback is invoked by SQLite after the commit has taken place and 6408 ** the associated write-lock on the database released, so the implementation 6409 ** may read, write or [checkpoint] the database as required. 6410 ** 6411 ** ^The first parameter passed to the callback function when it is invoked 6412 ** is a copy of the third parameter passed to sqlite3_wal_hook() when 6413 ** registering the callback. ^The second is a copy of the database handle. 6414 ** ^The third parameter is the name of the database that was written to - 6415 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 6416 ** is the number of pages currently in the write-ahead log file, 6417 ** including those that were just committed. 6418 ** 6419 ** The callback function should normally return [SQLITE_OK]. ^If an error 6420 ** code is returned, that error will propagate back up through the 6421 ** SQLite code base to cause the statement that provoked the callback 6422 ** to report an error, though the commit will have still occurred. If the 6423 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 6424 ** that does not correspond to any valid SQLite error code, the results 6425 ** are undefined. 6426 ** 6427 ** A single database handle may have at most a single write-ahead log callback 6428 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 6429 ** previously registered write-ahead log callback. ^Note that the 6430 ** [sqlite3_wal_autocheckpoint()] interface and the 6431 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 6432 ** those overwrite any prior [sqlite3_wal_hook()] settings. 6433 */ 6434 SQLITE_API void *sqlite3_wal_hook( 6435 sqlite3*, 6436 int(*)(void *,sqlite3*,const char*,int), 6437 void* 6438 ); 6439 6440 /* 6441 ** CAPI3REF: Configure an auto-checkpoint 6442 ** 6443 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 6444 ** [sqlite3_wal_hook()] that causes any database on [database connection] D 6445 ** to automatically [checkpoint] 6446 ** after committing a transaction if there are N or 6447 ** more frames in the [write-ahead log] file. ^Passing zero or 6448 ** a negative value as the nFrame parameter disables automatic 6449 ** checkpoints entirely. 6450 ** 6451 ** ^The callback registered by this function replaces any existing callback 6452 ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 6453 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 6454 ** configured by this function. 6455 ** 6456 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 6457 ** from SQL. 6458 ** 6459 ** ^Every new [database connection] defaults to having the auto-checkpoint 6460 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 6461 ** pages. The use of this interface 6462 ** is only necessary if the default setting is found to be suboptimal 6463 ** for a particular application. 6464 */ 6465 SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 6466 6467 /* 6468 ** CAPI3REF: Checkpoint a database 6469 ** 6470 ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 6471 ** on [database connection] D to be [checkpointed]. ^If X is NULL or an 6472 ** empty string, then a checkpoint is run on all databases of 6473 ** connection D. ^If the database connection D is not in 6474 ** [WAL | write-ahead log mode] then this interface is a harmless no-op. 6475 ** 6476 ** ^The [wal_checkpoint pragma] can be used to invoke this interface 6477 ** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 6478 ** [wal_autocheckpoint pragma] can be used to cause this interface to be 6479 ** run whenever the WAL reaches a certain size threshold. 6480 ** 6481 ** See also: [sqlite3_wal_checkpoint_v2()] 6482 */ 6483 SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 6484 6485 /* 6486 ** CAPI3REF: Checkpoint a database 6487 ** 6488 ** Run a checkpoint operation on WAL database zDb attached to database 6489 ** handle db. The specific operation is determined by the value of the 6490 ** eMode parameter: 6491 ** 6492 ** <dl> 6493 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 6494 ** Checkpoint as many frames as possible without waiting for any database 6495 ** readers or writers to finish. Sync the db file if all frames in the log 6496 ** are checkpointed. This mode is the same as calling 6497 ** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked. 6498 ** 6499 ** <dt>SQLITE_CHECKPOINT_FULL<dd> 6500 ** This mode blocks (calls the busy-handler callback) until there is no 6501 ** database writer and all readers are reading from the most recent database 6502 ** snapshot. It then checkpoints all frames in the log file and syncs the 6503 ** database file. This call blocks database writers while it is running, 6504 ** but not database readers. 6505 ** 6506 ** <dt>SQLITE_CHECKPOINT_RESTART<dd> 6507 ** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after 6508 ** checkpointing the log file it blocks (calls the busy-handler callback) 6509 ** until all readers are reading from the database file only. This ensures 6510 ** that the next client to write to the database file restarts the log file 6511 ** from the beginning. This call blocks database writers while it is running, 6512 ** but not database readers. 6513 ** </dl> 6514 ** 6515 ** If pnLog is not NULL, then *pnLog is set to the total number of frames in 6516 ** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to 6517 ** the total number of checkpointed frames (including any that were already 6518 ** checkpointed when this function is called). *pnLog and *pnCkpt may be 6519 ** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK. 6520 ** If no values are available because of an error, they are both set to -1 6521 ** before returning to communicate this to the caller. 6522 ** 6523 ** All calls obtain an exclusive "checkpoint" lock on the database file. If 6524 ** any other process is running a checkpoint operation at the same time, the 6525 ** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a 6526 ** busy-handler configured, it will not be invoked in this case. 6527 ** 6528 ** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive 6529 ** "writer" lock on the database file. If the writer lock cannot be obtained 6530 ** immediately, and a busy-handler is configured, it is invoked and the writer 6531 ** lock retried until either the busy-handler returns 0 or the lock is 6532 ** successfully obtained. The busy-handler is also invoked while waiting for 6533 ** database readers as described above. If the busy-handler returns 0 before 6534 ** the writer lock is obtained or while waiting for database readers, the 6535 ** checkpoint operation proceeds from that point in the same way as 6536 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 6537 ** without blocking any further. SQLITE_BUSY is returned in this case. 6538 ** 6539 ** If parameter zDb is NULL or points to a zero length string, then the 6540 ** specified operation is attempted on all WAL databases. In this case the 6541 ** values written to output parameters *pnLog and *pnCkpt are undefined. If 6542 ** an SQLITE_BUSY error is encountered when processing one or more of the 6543 ** attached WAL databases, the operation is still attempted on any remaining 6544 ** attached databases and SQLITE_BUSY is returned to the caller. If any other 6545 ** error occurs while processing an attached database, processing is abandoned 6546 ** and the error code returned to the caller immediately. If no error 6547 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached 6548 ** databases, SQLITE_OK is returned. 6549 ** 6550 ** If database zDb is the name of an attached database that is not in WAL 6551 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If 6552 ** zDb is not NULL (or a zero length string) and is not the name of any 6553 ** attached database, SQLITE_ERROR is returned to the caller. 6554 */ 6555 SQLITE_API int sqlite3_wal_checkpoint_v2( 6556 sqlite3 *db, /* Database handle */ 6557 const char *zDb, /* Name of attached database (or NULL) */ 6558 int eMode, /* SQLITE_CHECKPOINT_* value */ 6559 int *pnLog, /* OUT: Size of WAL log in frames */ 6560 int *pnCkpt /* OUT: Total number of frames checkpointed */ 6561 ); 6562 6563 /* 6564 ** CAPI3REF: Checkpoint operation parameters 6565 ** 6566 ** These constants can be used as the 3rd parameter to 6567 ** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()] 6568 ** documentation for additional information about the meaning and use of 6569 ** each of these values. 6570 */ 6571 #define SQLITE_CHECKPOINT_PASSIVE 0 6572 #define SQLITE_CHECKPOINT_FULL 1 6573 #define SQLITE_CHECKPOINT_RESTART 2 6574 6575 /* 6576 ** CAPI3REF: Virtual Table Interface Configuration 6577 ** 6578 ** This function may be called by either the [xConnect] or [xCreate] method 6579 ** of a [virtual table] implementation to configure 6580 ** various facets of the virtual table interface. 6581 ** 6582 ** If this interface is invoked outside the context of an xConnect or 6583 ** xCreate virtual table method then the behavior is undefined. 6584 ** 6585 ** At present, there is only one option that may be configured using 6586 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 6587 ** may be added in the future. 6588 */ 6589 SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...); 6590 6591 /* 6592 ** CAPI3REF: Virtual Table Configuration Options 6593 ** 6594 ** These macros define the various options to the 6595 ** [sqlite3_vtab_config()] interface that [virtual table] implementations 6596 ** can use to customize and optimize their behavior. 6597 ** 6598 ** <dl> 6599 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 6600 ** <dd>Calls of the form 6601 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 6602 ** where X is an integer. If X is zero, then the [virtual table] whose 6603 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 6604 ** support constraints. In this configuration (which is the default) if 6605 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 6606 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 6607 ** specified as part of the users SQL statement, regardless of the actual 6608 ** ON CONFLICT mode specified. 6609 ** 6610 ** If X is non-zero, then the virtual table implementation guarantees 6611 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 6612 ** any modifications to internal or persistent data structures have been made. 6613 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 6614 ** is able to roll back a statement or database transaction, and abandon 6615 ** or continue processing the current SQL statement as appropriate. 6616 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 6617 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 6618 ** had been ABORT. 6619 ** 6620 ** Virtual table implementations that are required to handle OR REPLACE 6621 ** must do so within the [xUpdate] method. If a call to the 6622 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON 6623 ** CONFLICT policy is REPLACE, the virtual table implementation should 6624 ** silently replace the appropriate rows within the xUpdate callback and 6625 ** return SQLITE_OK. Or, if this is not possible, it may return 6626 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 6627 ** constraint handling. 6628 ** </dl> 6629 */ 6630 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 6631 6632 /* 6633 ** CAPI3REF: Determine The Virtual Table Conflict Policy 6634 ** 6635 ** This function may only be called from within a call to the [xUpdate] method 6636 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 6637 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 6638 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 6639 ** of the SQL statement that triggered the call to the [xUpdate] method of the 6640 ** [virtual table]. 6641 */ 6642 SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *); 6643 6644 /* 6645 ** CAPI3REF: Conflict resolution modes 6646 ** 6647 ** These constants are returned by [sqlite3_vtab_on_conflict()] to 6648 ** inform a [virtual table] implementation what the [ON CONFLICT] mode 6649 ** is for the SQL statement being evaluated. 6650 ** 6651 ** Note that the [SQLITE_IGNORE] constant is also used as a potential 6652 ** return value from the [sqlite3_set_authorizer()] callback and that 6653 ** [SQLITE_ABORT] is also a [result code]. 6654 */ 6655 #define SQLITE_ROLLBACK 1 6656 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 6657 #define SQLITE_FAIL 3 6658 /* #define SQLITE_ABORT 4 // Also an error code */ 6659 #define SQLITE_REPLACE 5 6660 6661 6662 6663 /* 6664 ** Undo the hack that converts floating point types to integer for 6665 ** builds on processors without floating point support. 6666 */ 6667 #ifdef SQLITE_OMIT_FLOATING_POINT 6668 # undef double 6669 #endif 6670 6671 #ifdef __cplusplus 6672 } /* End of the 'extern "C"' block */ 6673 #endif 6674 #endif 6675 6676 /* 6677 ** 2010 August 30 6678 ** 6679 ** The author disclaims copyright to this source code. In place of 6680 ** a legal notice, here is a blessing: 6681 ** 6682 ** May you do good and not evil. 6683 ** May you find forgiveness for yourself and forgive others. 6684 ** May you share freely, never taking more than you give. 6685 ** 6686 ************************************************************************* 6687 */ 6688 6689 #ifndef _SQLITE3RTREE_H_ 6690 #define _SQLITE3RTREE_H_ 6691 6692 6693 #ifdef __cplusplus 6694 extern "C" { 6695 #endif 6696 6697 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry; 6698 6699 /* 6700 ** Register a geometry callback named zGeom that can be used as part of an 6701 ** R-Tree geometry query as follows: 6702 ** 6703 ** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...) 6704 */ 6705 SQLITE_API int sqlite3_rtree_geometry_callback( 6706 sqlite3 *db, 6707 const char *zGeom, 6708 int (*xGeom)(sqlite3_rtree_geometry *, int nCoord, double *aCoord, int *pRes), 6709 void *pContext 6710 ); 6711 6712 6713 /* 6714 ** A pointer to a structure of the following type is passed as the first 6715 ** argument to callbacks registered using rtree_geometry_callback(). 6716 */ 6717 struct sqlite3_rtree_geometry { 6718 void *pContext; /* Copy of pContext passed to s_r_g_c() */ 6719 int nParam; /* Size of array aParam[] */ 6720 double *aParam; /* Parameters passed to SQL geom function */ 6721 void *pUser; /* Callback implementation user data */ 6722 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */ 6723 }; 6724 6725 6726 #ifdef __cplusplus 6727 } /* end of the 'extern "C"' block */ 6728 #endif 6729 6730 #endif /* ifndef _SQLITE3RTREE_H_ */ 6731 6732
