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 41extern "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/* 53** These no-op macros are used in front of interfaces to mark those 54** interfaces as either deprecated or experimental. New applications 55** should not use deprecated interfaces - they are support for backwards 56** compatibility only. Application writers should be aware that 57** experimental interfaces are subject to change in point releases. 58** 59** These macros used to resolve to various kinds of compiler magic that 60** would generate warning messages when they were used. But that 61** compiler magic ended up generating such a flurry of bug reports 62** that we have taken it all out and gone back to using simple 63** noop macros. 64*/ 65#define SQLITE_DEPRECATED 66#define SQLITE_EXPERIMENTAL 67 68/* 69** Ensure these symbols were not defined by some previous header file. 70*/ 71#ifdef SQLITE_VERSION 72# undef SQLITE_VERSION 73#endif 74#ifdef SQLITE_VERSION_NUMBER 75# undef SQLITE_VERSION_NUMBER 76#endif 77 78/* 79** CAPI3REF: Compile-Time Library Version Numbers 80** 81** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 82** evaluates to a string literal that is the SQLite version in the 83** format "X.Y.Z" where X is the major version number (always 3 for 84** SQLite3) and Y is the minor version number and Z is the release number.)^ 85** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 86** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 87** numbers used in [SQLITE_VERSION].)^ 88** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 89** be larger than the release from which it is derived. Either Y will 90** be held constant and Z will be incremented or else Y will be incremented 91** and Z will be reset to zero. 92** 93** Since version 3.6.18, SQLite source code has been stored in the 94** <a href="http://www.fossil-scm.org/">Fossil configuration management 95** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 96** a string which identifies a particular check-in of SQLite 97** within its configuration management system. ^The SQLITE_SOURCE_ID 98** string contains the date and time of the check-in (UTC) and an SHA1 99** hash of the entire source tree. 100** 101** See also: [sqlite3_libversion()], 102** [sqlite3_libversion_number()], [sqlite3_sourceid()], 103** [sqlite_version()] and [sqlite_source_id()]. 104*/ 105#define SQLITE_VERSION "--VERS--" 106#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 107#define SQLITE_SOURCE_ID "--SOURCE-ID--" 108 109/* 110** CAPI3REF: Run-Time Library Version Numbers 111** KEYWORDS: sqlite3_version, sqlite3_sourceid 112** 113** These interfaces provide the same information as the [SQLITE_VERSION], 114** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 115** but are associated with the library instead of the header file. ^(Cautious 116** programmers might include assert() statements in their application to 117** verify that values returned by these interfaces match the macros in 118** the header, and thus insure that the application is 119** compiled with matching library and header files. 120** 121** <blockquote><pre> 122** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 123** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 124** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 125** </pre></blockquote>)^ 126** 127** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 128** macro. ^The sqlite3_libversion() function returns a pointer to the 129** to the sqlite3_version[] string constant. The sqlite3_libversion() 130** function is provided for use in DLLs since DLL users usually do not have 131** direct access to string constants within the DLL. ^The 132** sqlite3_libversion_number() function returns an integer equal to 133** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 134** a pointer to a string constant whose value is the same as the 135** [SQLITE_SOURCE_ID] C preprocessor macro. 136** 137** See also: [sqlite_version()] and [sqlite_source_id()]. 138*/ 139SQLITE_EXTERN const char sqlite3_version[]; 140const char *sqlite3_libversion(void); 141const char *sqlite3_sourceid(void); 142int sqlite3_libversion_number(void); 143 144/* 145** CAPI3REF: Run-Time Library Compilation Options Diagnostics 146** 147** ^The sqlite3_compileoption_used() function returns 0 or 1 148** indicating whether the specified option was defined at 149** compile time. ^The SQLITE_ prefix may be omitted from the 150** option name passed to sqlite3_compileoption_used(). 151** 152** ^The sqlite3_compileoption_get() function allows iterating 153** over the list of options that were defined at compile time by 154** returning the N-th compile time option string. ^If N is out of range, 155** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 156** prefix is omitted from any strings returned by 157** sqlite3_compileoption_get(). 158** 159** ^Support for the diagnostic functions sqlite3_compileoption_used() 160** and sqlite3_compileoption_get() may be omitted by specifying the 161** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 162** 163** See also: SQL functions [sqlite_compileoption_used()] and 164** [sqlite_compileoption_get()] and the [compile_options pragma]. 165*/ 166#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 167int sqlite3_compileoption_used(const char *zOptName); 168const char *sqlite3_compileoption_get(int N); 169#endif 170 171/* 172** CAPI3REF: Test To See If The Library Is Threadsafe 173** 174** ^The sqlite3_threadsafe() function returns zero if and only if 175** SQLite was compiled with mutexing code omitted due to the 176** [SQLITE_THREADSAFE] compile-time option being set to 0. 177** 178** SQLite can be compiled with or without mutexes. When 179** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 180** are enabled and SQLite is threadsafe. When the 181** [SQLITE_THREADSAFE] macro is 0, 182** the mutexes are omitted. Without the mutexes, it is not safe 183** to use SQLite concurrently from more than one thread. 184** 185** Enabling mutexes incurs a measurable performance penalty. 186** So if speed is of utmost importance, it makes sense to disable 187** the mutexes. But for maximum safety, mutexes should be enabled. 188** ^The default behavior is for mutexes to be enabled. 189** 190** This interface can be used by an application to make sure that the 191** version of SQLite that it is linking against was compiled with 192** the desired setting of the [SQLITE_THREADSAFE] macro. 193** 194** This interface only reports on the compile-time mutex setting 195** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 196** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 197** can be fully or partially disabled using a call to [sqlite3_config()] 198** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 199** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the 200** sqlite3_threadsafe() function shows only the compile-time setting of 201** thread safety, not any run-time changes to that setting made by 202** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 203** is unchanged by calls to sqlite3_config().)^ 204** 205** See the [threading mode] documentation for additional information. 206*/ 207int sqlite3_threadsafe(void); 208 209/* 210** CAPI3REF: Database Connection Handle 211** KEYWORDS: {database connection} {database connections} 212** 213** Each open SQLite database is represented by a pointer to an instance of 214** the opaque structure named "sqlite3". It is useful to think of an sqlite3 215** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 216** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 217** is its destructor. There are many other interfaces (such as 218** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 219** [sqlite3_busy_timeout()] to name but three) that are methods on an 220** sqlite3 object. 221*/ 222typedef struct sqlite3 sqlite3; 223 224/* 225** CAPI3REF: 64-Bit Integer Types 226** KEYWORDS: sqlite_int64 sqlite_uint64 227** 228** Because there is no cross-platform way to specify 64-bit integer types 229** SQLite includes typedefs for 64-bit signed and unsigned integers. 230** 231** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 232** The sqlite_int64 and sqlite_uint64 types are supported for backwards 233** compatibility only. 234** 235** ^The sqlite3_int64 and sqlite_int64 types can store integer values 236** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 237** sqlite3_uint64 and sqlite_uint64 types can store integer values 238** between 0 and +18446744073709551615 inclusive. 239*/ 240#ifdef SQLITE_INT64_TYPE 241 typedef SQLITE_INT64_TYPE sqlite_int64; 242 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 243#elif defined(_MSC_VER) || defined(__BORLANDC__) 244 typedef __int64 sqlite_int64; 245 typedef unsigned __int64 sqlite_uint64; 246#else 247 typedef long long int sqlite_int64; 248 typedef unsigned long long int sqlite_uint64; 249#endif 250typedef sqlite_int64 sqlite3_int64; 251typedef sqlite_uint64 sqlite3_uint64; 252 253/* 254** If compiling for a processor that lacks floating point support, 255** substitute integer for floating-point. 256*/ 257#ifdef SQLITE_OMIT_FLOATING_POINT 258# define double sqlite3_int64 259#endif 260 261/* 262** CAPI3REF: Closing A Database Connection 263** 264** ^The sqlite3_close() routine is the destructor for the [sqlite3] object. 265** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is 266** successfully destroyed and all associated resources are deallocated. 267** 268** Applications must [sqlite3_finalize | finalize] all [prepared statements] 269** and [sqlite3_blob_close | close] all [BLOB handles] associated with 270** the [sqlite3] object prior to attempting to close the object. ^If 271** sqlite3_close() is called on a [database connection] that still has 272** outstanding [prepared statements] or [BLOB handles], then it returns 273** SQLITE_BUSY. 274** 275** ^If [sqlite3_close()] is invoked while a transaction is open, 276** the transaction is automatically rolled back. 277** 278** The C parameter to [sqlite3_close(C)] must be either a NULL 279** pointer or an [sqlite3] object pointer obtained 280** from [sqlite3_open()], [sqlite3_open16()], or 281** [sqlite3_open_v2()], and not previously closed. 282** ^Calling sqlite3_close() with a NULL pointer argument is a 283** harmless no-op. 284*/ 285int sqlite3_close(sqlite3 *); 286 287/* 288** The type for a callback function. 289** This is legacy and deprecated. It is included for historical 290** compatibility and is not documented. 291*/ 292typedef int (*sqlite3_callback)(void*,int,char**, char**); 293 294/* 295** CAPI3REF: One-Step Query Execution Interface 296** 297** The sqlite3_exec() interface is a convenience wrapper around 298** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 299** that allows an application to run multiple statements of SQL 300** without having to use a lot of C code. 301** 302** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 303** semicolon-separate SQL statements passed into its 2nd argument, 304** in the context of the [database connection] passed in as its 1st 305** argument. ^If the callback function of the 3rd argument to 306** sqlite3_exec() is not NULL, then it is invoked for each result row 307** coming out of the evaluated SQL statements. ^The 4th argument to 308** sqlite3_exec() is relayed through to the 1st argument of each 309** callback invocation. ^If the callback pointer to sqlite3_exec() 310** is NULL, then no callback is ever invoked and result rows are 311** ignored. 312** 313** ^If an error occurs while evaluating the SQL statements passed into 314** sqlite3_exec(), then execution of the current statement stops and 315** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 316** is not NULL then any error message is written into memory obtained 317** from [sqlite3_malloc()] and passed back through the 5th parameter. 318** To avoid memory leaks, the application should invoke [sqlite3_free()] 319** on error message strings returned through the 5th parameter of 320** of sqlite3_exec() after the error message string is no longer needed. 321** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 322** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 323** NULL before returning. 324** 325** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 326** routine returns SQLITE_ABORT without invoking the callback again and 327** without running any subsequent SQL statements. 328** 329** ^The 2nd argument to the sqlite3_exec() callback function is the 330** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 331** callback is an array of pointers to strings obtained as if from 332** [sqlite3_column_text()], one for each column. ^If an element of a 333** result row is NULL then the corresponding string pointer for the 334** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 335** sqlite3_exec() callback is an array of pointers to strings where each 336** entry represents the name of corresponding result column as obtained 337** from [sqlite3_column_name()]. 338** 339** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 340** to an empty string, or a pointer that contains only whitespace and/or 341** SQL comments, then no SQL statements are evaluated and the database 342** is not changed. 343** 344** Restrictions: 345** 346** <ul> 347** <li> The application must insure that the 1st parameter to sqlite3_exec() 348** is a valid and open [database connection]. 349** <li> The application must not close [database connection] specified by 350** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 351** <li> The application must not modify the SQL statement text passed into 352** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 353** </ul> 354*/ 355int sqlite3_exec( 356 sqlite3*, /* An open database */ 357 const char *sql, /* SQL to be evaluated */ 358 int (*callback)(void*,int,char**,char**), /* Callback function */ 359 void *, /* 1st argument to callback */ 360 char **errmsg /* Error msg written here */ 361); 362 363/* 364** CAPI3REF: Result Codes 365** KEYWORDS: SQLITE_OK {error code} {error codes} 366** KEYWORDS: {result code} {result codes} 367** 368** Many SQLite functions return an integer result code from the set shown 369** here in order to indicate success or failure. 370** 371** New error codes may be added in future versions of SQLite. 372** 373** See also: [SQLITE_IOERR_READ | extended result codes], 374** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes]. 375*/ 376#define SQLITE_OK 0 /* Successful result */ 377/* beginning-of-error-codes */ 378#define SQLITE_ERROR 1 /* SQL error or missing database */ 379#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 380#define SQLITE_PERM 3 /* Access permission denied */ 381#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 382#define SQLITE_BUSY 5 /* The database file is locked */ 383#define SQLITE_LOCKED 6 /* A table in the database is locked */ 384#define SQLITE_NOMEM 7 /* A malloc() failed */ 385#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 386#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 387#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 388#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 389#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 390#define SQLITE_FULL 13 /* Insertion failed because database is full */ 391#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 392#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 393#define SQLITE_EMPTY 16 /* Database is empty */ 394#define SQLITE_SCHEMA 17 /* The database schema changed */ 395#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 396#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 397#define SQLITE_MISMATCH 20 /* Data type mismatch */ 398#define SQLITE_MISUSE 21 /* Library used incorrectly */ 399#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 400#define SQLITE_AUTH 23 /* Authorization denied */ 401#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 402#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 403#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 404#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 405#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 406/* end-of-error-codes */ 407 408/* 409** CAPI3REF: Extended Result Codes 410** KEYWORDS: {extended error code} {extended error codes} 411** KEYWORDS: {extended result code} {extended result codes} 412** 413** In its default configuration, SQLite API routines return one of 26 integer 414** [SQLITE_OK | result codes]. However, experience has shown that many of 415** these result codes are too coarse-grained. They do not provide as 416** much information about problems as programmers might like. In an effort to 417** address this, newer versions of SQLite (version 3.3.8 and later) include 418** support for additional result codes that provide more detailed information 419** about errors. The extended result codes are enabled or disabled 420** on a per database connection basis using the 421** [sqlite3_extended_result_codes()] API. 422** 423** Some of the available extended result codes are listed here. 424** One may expect the number of extended result codes will be expand 425** over time. Software that uses extended result codes should expect 426** to see new result codes in future releases of SQLite. 427** 428** The SQLITE_OK result code will never be extended. It will always 429** be exactly zero. 430*/ 431#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 432#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 433#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 434#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 435#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 436#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 437#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 438#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 439#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 440#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 441#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 442#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 443#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 444#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 445#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 446#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 447#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 448#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 449#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 450#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 451#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 452#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 453#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 454#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 455#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 456#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 457#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 458#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 459#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 460#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 461 462/* 463** CAPI3REF: Flags For File Open Operations 464** 465** These bit values are intended for use in the 466** 3rd parameter to the [sqlite3_open_v2()] interface and 467** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 468*/ 469#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 470#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 471#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 472#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 473#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 474#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 475#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 476#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 477#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 478#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 479#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 480#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 481#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 482#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 483#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 484#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 485#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 486#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 487#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 488#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 489 490/* Reserved: 0x00F00000 */ 491 492/* 493** CAPI3REF: Device Characteristics 494** 495** The xDeviceCharacteristics method of the [sqlite3_io_methods] 496** object returns an integer which is a vector of the these 497** bit values expressing I/O characteristics of the mass storage 498** device that holds the file that the [sqlite3_io_methods] 499** refers to. 500** 501** The SQLITE_IOCAP_ATOMIC property means that all writes of 502** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 503** mean that writes of blocks that are nnn bytes in size and 504** are aligned to an address which is an integer multiple of 505** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 506** that when data is appended to a file, the data is appended 507** first then the size of the file is extended, never the other 508** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 509** information is written to disk in the same order as calls 510** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 511** after reboot following a crash or power loss, the only bytes in a 512** file that were written at the application level might have changed 513** and that adjacent bytes, even bytes within the same sector are 514** guaranteed to be unchanged. 515*/ 516#define SQLITE_IOCAP_ATOMIC 0x00000001 517#define SQLITE_IOCAP_ATOMIC512 0x00000002 518#define SQLITE_IOCAP_ATOMIC1K 0x00000004 519#define SQLITE_IOCAP_ATOMIC2K 0x00000008 520#define SQLITE_IOCAP_ATOMIC4K 0x00000010 521#define SQLITE_IOCAP_ATOMIC8K 0x00000020 522#define SQLITE_IOCAP_ATOMIC16K 0x00000040 523#define SQLITE_IOCAP_ATOMIC32K 0x00000080 524#define SQLITE_IOCAP_ATOMIC64K 0x00000100 525#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 526#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 527#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 528#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 529 530/* 531** CAPI3REF: File Locking Levels 532** 533** SQLite uses one of these integer values as the second 534** argument to calls it makes to the xLock() and xUnlock() methods 535** of an [sqlite3_io_methods] object. 536*/ 537#define SQLITE_LOCK_NONE 0 538#define SQLITE_LOCK_SHARED 1 539#define SQLITE_LOCK_RESERVED 2 540#define SQLITE_LOCK_PENDING 3 541#define SQLITE_LOCK_EXCLUSIVE 4 542 543/* 544** CAPI3REF: Synchronization Type Flags 545** 546** When SQLite invokes the xSync() method of an 547** [sqlite3_io_methods] object it uses a combination of 548** these integer values as the second argument. 549** 550** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 551** sync operation only needs to flush data to mass storage. Inode 552** information need not be flushed. If the lower four bits of the flag 553** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 554** If the lower four bits equal SQLITE_SYNC_FULL, that means 555** to use Mac OS X style fullsync instead of fsync(). 556** 557** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 558** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 559** settings. The [synchronous pragma] determines when calls to the 560** xSync VFS method occur and applies uniformly across all platforms. 561** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 562** energetic or rigorous or forceful the sync operations are and 563** only make a difference on Mac OSX for the default SQLite code. 564** (Third-party VFS implementations might also make the distinction 565** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 566** operating systems natively supported by SQLite, only Mac OSX 567** cares about the difference.) 568*/ 569#define SQLITE_SYNC_NORMAL 0x00002 570#define SQLITE_SYNC_FULL 0x00003 571#define SQLITE_SYNC_DATAONLY 0x00010 572 573/* 574** CAPI3REF: OS Interface Open File Handle 575** 576** An [sqlite3_file] object represents an open file in the 577** [sqlite3_vfs | OS interface layer]. Individual OS interface 578** implementations will 579** want to subclass this object by appending additional fields 580** for their own use. The pMethods entry is a pointer to an 581** [sqlite3_io_methods] object that defines methods for performing 582** I/O operations on the open file. 583*/ 584typedef struct sqlite3_file sqlite3_file; 585struct sqlite3_file { 586 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 587}; 588 589/* 590** CAPI3REF: OS Interface File Virtual Methods Object 591** 592** Every file opened by the [sqlite3_vfs.xOpen] method populates an 593** [sqlite3_file] object (or, more commonly, a subclass of the 594** [sqlite3_file] object) with a pointer to an instance of this object. 595** This object defines the methods used to perform various operations 596** against the open file represented by the [sqlite3_file] object. 597** 598** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 599** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 600** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 601** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 602** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 603** to NULL. 604** 605** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 606** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 607** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 608** flag may be ORed in to indicate that only the data of the file 609** and not its inode needs to be synced. 610** 611** The integer values to xLock() and xUnlock() are one of 612** <ul> 613** <li> [SQLITE_LOCK_NONE], 614** <li> [SQLITE_LOCK_SHARED], 615** <li> [SQLITE_LOCK_RESERVED], 616** <li> [SQLITE_LOCK_PENDING], or 617** <li> [SQLITE_LOCK_EXCLUSIVE]. 618** </ul> 619** xLock() increases the lock. xUnlock() decreases the lock. 620** The xCheckReservedLock() method checks whether any database connection, 621** either in this process or in some other process, is holding a RESERVED, 622** PENDING, or EXCLUSIVE lock on the file. It returns true 623** if such a lock exists and false otherwise. 624** 625** The xFileControl() method is a generic interface that allows custom 626** VFS implementations to directly control an open file using the 627** [sqlite3_file_control()] interface. The second "op" argument is an 628** integer opcode. The third argument is a generic pointer intended to 629** point to a structure that may contain arguments or space in which to 630** write return values. Potential uses for xFileControl() might be 631** functions to enable blocking locks with timeouts, to change the 632** locking strategy (for example to use dot-file locks), to inquire 633** about the status of a lock, or to break stale locks. The SQLite 634** core reserves all opcodes less than 100 for its own use. 635** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 636** Applications that define a custom xFileControl method should use opcodes 637** greater than 100 to avoid conflicts. VFS implementations should 638** return [SQLITE_NOTFOUND] for file control opcodes that they do not 639** recognize. 640** 641** The xSectorSize() method returns the sector size of the 642** device that underlies the file. The sector size is the 643** minimum write that can be performed without disturbing 644** other bytes in the file. The xDeviceCharacteristics() 645** method returns a bit vector describing behaviors of the 646** underlying device: 647** 648** <ul> 649** <li> [SQLITE_IOCAP_ATOMIC] 650** <li> [SQLITE_IOCAP_ATOMIC512] 651** <li> [SQLITE_IOCAP_ATOMIC1K] 652** <li> [SQLITE_IOCAP_ATOMIC2K] 653** <li> [SQLITE_IOCAP_ATOMIC4K] 654** <li> [SQLITE_IOCAP_ATOMIC8K] 655** <li> [SQLITE_IOCAP_ATOMIC16K] 656** <li> [SQLITE_IOCAP_ATOMIC32K] 657** <li> [SQLITE_IOCAP_ATOMIC64K] 658** <li> [SQLITE_IOCAP_SAFE_APPEND] 659** <li> [SQLITE_IOCAP_SEQUENTIAL] 660** </ul> 661** 662** The SQLITE_IOCAP_ATOMIC property means that all writes of 663** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 664** mean that writes of blocks that are nnn bytes in size and 665** are aligned to an address which is an integer multiple of 666** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 667** that when data is appended to a file, the data is appended 668** first then the size of the file is extended, never the other 669** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 670** information is written to disk in the same order as calls 671** to xWrite(). 672** 673** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 674** in the unread portions of the buffer with zeros. A VFS that 675** fails to zero-fill short reads might seem to work. However, 676** failure to zero-fill short reads will eventually lead to 677** database corruption. 678*/ 679typedef struct sqlite3_io_methods sqlite3_io_methods; 680struct sqlite3_io_methods { 681 int iVersion; 682 int (*xClose)(sqlite3_file*); 683 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 684 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 685 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 686 int (*xSync)(sqlite3_file*, int flags); 687 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 688 int (*xLock)(sqlite3_file*, int); 689 int (*xUnlock)(sqlite3_file*, int); 690 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 691 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 692 int (*xSectorSize)(sqlite3_file*); 693 int (*xDeviceCharacteristics)(sqlite3_file*); 694 /* Methods above are valid for version 1 */ 695 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 696 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 697 void (*xShmBarrier)(sqlite3_file*); 698 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 699 /* Methods above are valid for version 2 */ 700 /* Additional methods may be added in future releases */ 701}; 702 703/* 704** CAPI3REF: Standard File Control Opcodes 705** 706** These integer constants are opcodes for the xFileControl method 707** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 708** interface. 709** 710** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 711** opcode causes the xFileControl method to write the current state of 712** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 713** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 714** into an integer that the pArg argument points to. This capability 715** is used during testing and only needs to be supported when SQLITE_TEST 716** is defined. 717** <ul> 718** <li>[[SQLITE_FCNTL_SIZE_HINT]] 719** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 720** layer a hint of how large the database file will grow to be during the 721** current transaction. This hint is not guaranteed to be accurate but it 722** is often close. The underlying VFS might choose to preallocate database 723** file space based on this hint in order to help writes to the database 724** file run faster. 725** 726** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 727** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 728** extends and truncates the database file in chunks of a size specified 729** by the user. The fourth argument to [sqlite3_file_control()] should 730** point to an integer (type int) containing the new chunk-size to use 731** for the nominated database. Allocating database file space in large 732** chunks (say 1MB at a time), may reduce file-system fragmentation and 733** improve performance on some systems. 734** 735** <li>[[SQLITE_FCNTL_FILE_POINTER]] 736** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 737** to the [sqlite3_file] object associated with a particular database 738** connection. See the [sqlite3_file_control()] documentation for 739** additional information. 740** 741** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 742** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by 743** SQLite and sent to all VFSes in place of a call to the xSync method 744** when the database connection has [PRAGMA synchronous] set to OFF.)^ 745** Some specialized VFSes need this signal in order to operate correctly 746** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most 747** VFSes do not need this signal and should silently ignore this opcode. 748** Applications should not call [sqlite3_file_control()] with this 749** opcode as doing so may disrupt the operation of the specialized VFSes 750** that do require it. 751** 752** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 753** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 754** retry counts and intervals for certain disk I/O operations for the 755** windows [VFS] in order to provide robustness in the presence of 756** anti-virus programs. By default, the windows VFS will retry file read, 757** file write, and file delete operations up to 10 times, with a delay 758** of 25 milliseconds before the first retry and with the delay increasing 759** by an additional 25 milliseconds with each subsequent retry. This 760** opcode allows these two values (10 retries and 25 milliseconds of delay) 761** to be adjusted. The values are changed for all database connections 762** within the same process. The argument is a pointer to an array of two 763** integers where the first integer i the new retry count and the second 764** integer is the delay. If either integer is negative, then the setting 765** is not changed but instead the prior value of that setting is written 766** into the array entry, allowing the current retry settings to be 767** interrogated. The zDbName parameter is ignored. 768** 769** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 770** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 771** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 772** write ahead log and shared memory files used for transaction control 773** are automatically deleted when the latest connection to the database 774** closes. Setting persistent WAL mode causes those files to persist after 775** close. Persisting the files is useful when other processes that do not 776** have write permission on the directory containing the database file want 777** to read the database file, as the WAL and shared memory files must exist 778** in order for the database to be readable. The fourth parameter to 779** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 780** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 781** WAL mode. If the integer is -1, then it is overwritten with the current 782** WAL persistence setting. 783** 784** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 785** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 786** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 787** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 788** xDeviceCharacteristics methods. The fourth parameter to 789** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 790** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 791** mode. If the integer is -1, then it is overwritten with the current 792** zero-damage mode setting. 793** 794** <li>[[SQLITE_FCNTL_OVERWRITE]] 795** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 796** a write transaction to indicate that, unless it is rolled back for some 797** reason, the entire database file will be overwritten by the current 798** transaction. This is used by VACUUM operations. 799** 800** <li>[[SQLITE_FCNTL_VFSNAME]] 801** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 802** all [VFSes] in the VFS stack. The names are of all VFS shims and the 803** final bottom-level VFS are written into memory obtained from 804** [sqlite3_malloc()] and the result is stored in the char* variable 805** that the fourth parameter of [sqlite3_file_control()] points to. 806** The caller is responsible for freeing the memory when done. As with 807** all file-control actions, there is no guarantee that this will actually 808** do anything. Callers should initialize the char* variable to a NULL 809** pointer in case this file-control is not implemented. This file-control 810** is intended for diagnostic use only. 811** 812** <li>[[SQLITE_FCNTL_PRAGMA]] 813** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 814** file control is sent to the open [sqlite3_file] object corresponding 815** to the database file to which the pragma statement refers. ^The argument 816** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 817** pointers to strings (char**) in which the second element of the array 818** is the name of the pragma and the third element is the argument to the 819** pragma or NULL if the pragma has no argument. ^The handler for an 820** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 821** of the char** argument point to a string obtained from [sqlite3_mprintf()] 822** or the equivalent and that string will become the result of the pragma or 823** the error message if the pragma fails. ^If the 824** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 825** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 826** file control returns [SQLITE_OK], then the parser assumes that the 827** VFS has handled the PRAGMA itself and the parser generates a no-op 828** prepared statement. ^If the [SQLITE_FCNTL_PRAGMA] file control returns 829** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 830** that the VFS encountered an error while handling the [PRAGMA] and the 831** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 832** file control occurs at the beginning of pragma statement analysis and so 833** it is able to override built-in [PRAGMA] statements. 834** </ul> 835*/ 836#define SQLITE_FCNTL_LOCKSTATE 1 837#define SQLITE_GET_LOCKPROXYFILE 2 838#define SQLITE_SET_LOCKPROXYFILE 3 839#define SQLITE_LAST_ERRNO 4 840#define SQLITE_FCNTL_SIZE_HINT 5 841#define SQLITE_FCNTL_CHUNK_SIZE 6 842#define SQLITE_FCNTL_FILE_POINTER 7 843#define SQLITE_FCNTL_SYNC_OMITTED 8 844#define SQLITE_FCNTL_WIN32_AV_RETRY 9 845#define SQLITE_FCNTL_PERSIST_WAL 10 846#define SQLITE_FCNTL_OVERWRITE 11 847#define SQLITE_FCNTL_VFSNAME 12 848#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 849#define SQLITE_FCNTL_PRAGMA 14 850 851/* 852** CAPI3REF: Mutex Handle 853** 854** The mutex module within SQLite defines [sqlite3_mutex] to be an 855** abstract type for a mutex object. The SQLite core never looks 856** at the internal representation of an [sqlite3_mutex]. It only 857** deals with pointers to the [sqlite3_mutex] object. 858** 859** Mutexes are created using [sqlite3_mutex_alloc()]. 860*/ 861typedef struct sqlite3_mutex sqlite3_mutex; 862 863/* 864** CAPI3REF: OS Interface Object 865** 866** An instance of the sqlite3_vfs object defines the interface between 867** the SQLite core and the underlying operating system. The "vfs" 868** in the name of the object stands for "virtual file system". See 869** the [VFS | VFS documentation] for further information. 870** 871** The value of the iVersion field is initially 1 but may be larger in 872** future versions of SQLite. Additional fields may be appended to this 873** object when the iVersion value is increased. Note that the structure 874** of the sqlite3_vfs object changes in the transaction between 875** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 876** modified. 877** 878** The szOsFile field is the size of the subclassed [sqlite3_file] 879** structure used by this VFS. mxPathname is the maximum length of 880** a pathname in this VFS. 881** 882** Registered sqlite3_vfs objects are kept on a linked list formed by 883** the pNext pointer. The [sqlite3_vfs_register()] 884** and [sqlite3_vfs_unregister()] interfaces manage this list 885** in a thread-safe way. The [sqlite3_vfs_find()] interface 886** searches the list. Neither the application code nor the VFS 887** implementation should use the pNext pointer. 888** 889** The pNext field is the only field in the sqlite3_vfs 890** structure that SQLite will ever modify. SQLite will only access 891** or modify this field while holding a particular static mutex. 892** The application should never modify anything within the sqlite3_vfs 893** object once the object has been registered. 894** 895** The zName field holds the name of the VFS module. The name must 896** be unique across all VFS modules. 897** 898** [[sqlite3_vfs.xOpen]] 899** ^SQLite guarantees that the zFilename parameter to xOpen 900** is either a NULL pointer or string obtained 901** from xFullPathname() with an optional suffix added. 902** ^If a suffix is added to the zFilename parameter, it will 903** consist of a single "-" character followed by no more than 904** 11 alphanumeric and/or "-" characters. 905** ^SQLite further guarantees that 906** the string will be valid and unchanged until xClose() is 907** called. Because of the previous sentence, 908** the [sqlite3_file] can safely store a pointer to the 909** filename if it needs to remember the filename for some reason. 910** If the zFilename parameter to xOpen is a NULL pointer then xOpen 911** must invent its own temporary name for the file. ^Whenever the 912** xFilename parameter is NULL it will also be the case that the 913** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 914** 915** The flags argument to xOpen() includes all bits set in 916** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 917** or [sqlite3_open16()] is used, then flags includes at least 918** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 919** If xOpen() opens a file read-only then it sets *pOutFlags to 920** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 921** 922** ^(SQLite will also add one of the following flags to the xOpen() 923** call, depending on the object being opened: 924** 925** <ul> 926** <li> [SQLITE_OPEN_MAIN_DB] 927** <li> [SQLITE_OPEN_MAIN_JOURNAL] 928** <li> [SQLITE_OPEN_TEMP_DB] 929** <li> [SQLITE_OPEN_TEMP_JOURNAL] 930** <li> [SQLITE_OPEN_TRANSIENT_DB] 931** <li> [SQLITE_OPEN_SUBJOURNAL] 932** <li> [SQLITE_OPEN_MASTER_JOURNAL] 933** <li> [SQLITE_OPEN_WAL] 934** </ul>)^ 935** 936** The file I/O implementation can use the object type flags to 937** change the way it deals with files. For example, an application 938** that does not care about crash recovery or rollback might make 939** the open of a journal file a no-op. Writes to this journal would 940** also be no-ops, and any attempt to read the journal would return 941** SQLITE_IOERR. Or the implementation might recognize that a database 942** file will be doing page-aligned sector reads and writes in a random 943** order and set up its I/O subsystem accordingly. 944** 945** SQLite might also add one of the following flags to the xOpen method: 946** 947** <ul> 948** <li> [SQLITE_OPEN_DELETEONCLOSE] 949** <li> [SQLITE_OPEN_EXCLUSIVE] 950** </ul> 951** 952** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 953** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 954** will be set for TEMP databases and their journals, transient 955** databases, and subjournals. 956** 957** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 958** with the [SQLITE_OPEN_CREATE] flag, which are both directly 959** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 960** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 961** SQLITE_OPEN_CREATE, is used to indicate that file should always 962** be created, and that it is an error if it already exists. 963** It is <i>not</i> used to indicate the file should be opened 964** for exclusive access. 965** 966** ^At least szOsFile bytes of memory are allocated by SQLite 967** to hold the [sqlite3_file] structure passed as the third 968** argument to xOpen. The xOpen method does not have to 969** allocate the structure; it should just fill it in. Note that 970** the xOpen method must set the sqlite3_file.pMethods to either 971** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 972** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 973** element will be valid after xOpen returns regardless of the success 974** or failure of the xOpen call. 975** 976** [[sqlite3_vfs.xAccess]] 977** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 978** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 979** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 980** to test whether a file is at least readable. The file can be a 981** directory. 982** 983** ^SQLite will always allocate at least mxPathname+1 bytes for the 984** output buffer xFullPathname. The exact size of the output buffer 985** is also passed as a parameter to both methods. If the output buffer 986** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 987** handled as a fatal error by SQLite, vfs implementations should endeavor 988** to prevent this by setting mxPathname to a sufficiently large value. 989** 990** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 991** interfaces are not strictly a part of the filesystem, but they are 992** included in the VFS structure for completeness. 993** The xRandomness() function attempts to return nBytes bytes 994** of good-quality randomness into zOut. The return value is 995** the actual number of bytes of randomness obtained. 996** The xSleep() method causes the calling thread to sleep for at 997** least the number of microseconds given. ^The xCurrentTime() 998** method returns a Julian Day Number for the current date and time as 999** a floating point value. 1000** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1001** Day Number multiplied by 86400000 (the number of milliseconds in 1002** a 24-hour day). 1003** ^SQLite will use the xCurrentTimeInt64() method to get the current 1004** date and time if that method is available (if iVersion is 2 or 1005** greater and the function pointer is not NULL) and will fall back 1006** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1007** 1008** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1009** are not used by the SQLite core. These optional interfaces are provided 1010** by some VFSes to facilitate testing of the VFS code. By overriding 1011** system calls with functions under its control, a test program can 1012** simulate faults and error conditions that would otherwise be difficult 1013** or impossible to induce. The set of system calls that can be overridden 1014** varies from one VFS to another, and from one version of the same VFS to the 1015** next. Applications that use these interfaces must be prepared for any 1016** or all of these interfaces to be NULL or for their behavior to change 1017** from one release to the next. Applications must not attempt to access 1018** any of these methods if the iVersion of the VFS is less than 3. 1019*/ 1020typedef struct sqlite3_vfs sqlite3_vfs; 1021typedef void (*sqlite3_syscall_ptr)(void); 1022struct sqlite3_vfs { 1023 int iVersion; /* Structure version number (currently 3) */ 1024 int szOsFile; /* Size of subclassed sqlite3_file */ 1025 int mxPathname; /* Maximum file pathname length */ 1026 sqlite3_vfs *pNext; /* Next registered VFS */ 1027 const char *zName; /* Name of this virtual file system */ 1028 void *pAppData; /* Pointer to application-specific data */ 1029 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1030 int flags, int *pOutFlags); 1031 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1032 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1033 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1034 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1035 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1036 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1037 void (*xDlClose)(sqlite3_vfs*, void*); 1038 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1039 int (*xSleep)(sqlite3_vfs*, int microseconds); 1040 int (*xCurrentTime)(sqlite3_vfs*, double*); 1041 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1042 /* 1043 ** The methods above are in version 1 of the sqlite_vfs object 1044 ** definition. Those that follow are added in version 2 or later 1045 */ 1046 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1047 /* 1048 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1049 ** Those below are for version 3 and greater. 1050 */ 1051 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1052 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1053 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1054 /* 1055 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1056 ** New fields may be appended in figure versions. The iVersion 1057 ** value will increment whenever this happens. 1058 */ 1059}; 1060 1061/* 1062** CAPI3REF: Flags for the xAccess VFS method 1063** 1064** These integer constants can be used as the third parameter to 1065** the xAccess method of an [sqlite3_vfs] object. They determine 1066** what kind of permissions the xAccess method is looking for. 1067** With SQLITE_ACCESS_EXISTS, the xAccess method 1068** simply checks whether the file exists. 1069** With SQLITE_ACCESS_READWRITE, the xAccess method 1070** checks whether the named directory is both readable and writable 1071** (in other words, if files can be added, removed, and renamed within 1072** the directory). 1073** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1074** [temp_store_directory pragma], though this could change in a future 1075** release of SQLite. 1076** With SQLITE_ACCESS_READ, the xAccess method 1077** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1078** currently unused, though it might be used in a future release of 1079** SQLite. 1080*/ 1081#define SQLITE_ACCESS_EXISTS 0 1082#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1083#define SQLITE_ACCESS_READ 2 /* Unused */ 1084 1085/* 1086** CAPI3REF: Flags for the xShmLock VFS method 1087** 1088** These integer constants define the various locking operations 1089** allowed by the xShmLock method of [sqlite3_io_methods]. The 1090** following are the only legal combinations of flags to the 1091** xShmLock method: 1092** 1093** <ul> 1094** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1095** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1096** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1097** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1098** </ul> 1099** 1100** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1101** was given no the corresponding lock. 1102** 1103** The xShmLock method can transition between unlocked and SHARED or 1104** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1105** and EXCLUSIVE. 1106*/ 1107#define SQLITE_SHM_UNLOCK 1 1108#define SQLITE_SHM_LOCK 2 1109#define SQLITE_SHM_SHARED 4 1110#define SQLITE_SHM_EXCLUSIVE 8 1111 1112/* 1113** CAPI3REF: Maximum xShmLock index 1114** 1115** The xShmLock method on [sqlite3_io_methods] may use values 1116** between 0 and this upper bound as its "offset" argument. 1117** The SQLite core will never attempt to acquire or release a 1118** lock outside of this range 1119*/ 1120#define SQLITE_SHM_NLOCK 8 1121 1122 1123/* 1124** CAPI3REF: Initialize The SQLite Library 1125** 1126** ^The sqlite3_initialize() routine initializes the 1127** SQLite library. ^The sqlite3_shutdown() routine 1128** deallocates any resources that were allocated by sqlite3_initialize(). 1129** These routines are designed to aid in process initialization and 1130** shutdown on embedded systems. Workstation applications using 1131** SQLite normally do not need to invoke either of these routines. 1132** 1133** A call to sqlite3_initialize() is an "effective" call if it is 1134** the first time sqlite3_initialize() is invoked during the lifetime of 1135** the process, or if it is the first time sqlite3_initialize() is invoked 1136** following a call to sqlite3_shutdown(). ^(Only an effective call 1137** of sqlite3_initialize() does any initialization. All other calls 1138** are harmless no-ops.)^ 1139** 1140** A call to sqlite3_shutdown() is an "effective" call if it is the first 1141** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1142** an effective call to sqlite3_shutdown() does any deinitialization. 1143** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1144** 1145** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1146** is not. The sqlite3_shutdown() interface must only be called from a 1147** single thread. All open [database connections] must be closed and all 1148** other SQLite resources must be deallocated prior to invoking 1149** sqlite3_shutdown(). 1150** 1151** Among other things, ^sqlite3_initialize() will invoke 1152** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1153** will invoke sqlite3_os_end(). 1154** 1155** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1156** ^If for some reason, sqlite3_initialize() is unable to initialize 1157** the library (perhaps it is unable to allocate a needed resource such 1158** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1159** 1160** ^The sqlite3_initialize() routine is called internally by many other 1161** SQLite interfaces so that an application usually does not need to 1162** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1163** calls sqlite3_initialize() so the SQLite library will be automatically 1164** initialized when [sqlite3_open()] is called if it has not be initialized 1165** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1166** compile-time option, then the automatic calls to sqlite3_initialize() 1167** are omitted and the application must call sqlite3_initialize() directly 1168** prior to using any other SQLite interface. For maximum portability, 1169** it is recommended that applications always invoke sqlite3_initialize() 1170** directly prior to using any other SQLite interface. Future releases 1171** of SQLite may require this. In other words, the behavior exhibited 1172** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1173** default behavior in some future release of SQLite. 1174** 1175** The sqlite3_os_init() routine does operating-system specific 1176** initialization of the SQLite library. The sqlite3_os_end() 1177** routine undoes the effect of sqlite3_os_init(). Typical tasks 1178** performed by these routines include allocation or deallocation 1179** of static resources, initialization of global variables, 1180** setting up a default [sqlite3_vfs] module, or setting up 1181** a default configuration using [sqlite3_config()]. 1182** 1183** The application should never invoke either sqlite3_os_init() 1184** or sqlite3_os_end() directly. The application should only invoke 1185** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1186** interface is called automatically by sqlite3_initialize() and 1187** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1188** implementations for sqlite3_os_init() and sqlite3_os_end() 1189** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1190** When [custom builds | built for other platforms] 1191** (using the [SQLITE_OS_OTHER=1] compile-time 1192** option) the application must supply a suitable implementation for 1193** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1194** implementation of sqlite3_os_init() or sqlite3_os_end() 1195** must return [SQLITE_OK] on success and some other [error code] upon 1196** failure. 1197*/ 1198int sqlite3_initialize(void); 1199int sqlite3_shutdown(void); 1200int sqlite3_os_init(void); 1201int sqlite3_os_end(void); 1202 1203/* 1204** CAPI3REF: Configuring The SQLite Library 1205** 1206** The sqlite3_config() interface is used to make global configuration 1207** changes to SQLite in order to tune SQLite to the specific needs of 1208** the application. The default configuration is recommended for most 1209** applications and so this routine is usually not necessary. It is 1210** provided to support rare applications with unusual needs. 1211** 1212** The sqlite3_config() interface is not threadsafe. The application 1213** must insure that no other SQLite interfaces are invoked by other 1214** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1215** may only be invoked prior to library initialization using 1216** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1217** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1218** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1219** Note, however, that ^sqlite3_config() can be called as part of the 1220** implementation of an application-defined [sqlite3_os_init()]. 1221** 1222** The first argument to sqlite3_config() is an integer 1223** [configuration option] that determines 1224** what property of SQLite is to be configured. Subsequent arguments 1225** vary depending on the [configuration option] 1226** in the first argument. 1227** 1228** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1229** ^If the option is unknown or SQLite is unable to set the option 1230** then this routine returns a non-zero [error code]. 1231*/ 1232int sqlite3_config(int, ...); 1233 1234/* 1235** CAPI3REF: Configure database connections 1236** 1237** The sqlite3_db_config() interface is used to make configuration 1238** changes to a [database connection]. The interface is similar to 1239** [sqlite3_config()] except that the changes apply to a single 1240** [database connection] (specified in the first argument). 1241** 1242** The second argument to sqlite3_db_config(D,V,...) is the 1243** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1244** that indicates what aspect of the [database connection] is being configured. 1245** Subsequent arguments vary depending on the configuration verb. 1246** 1247** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1248** the call is considered successful. 1249*/ 1250int sqlite3_db_config(sqlite3*, int op, ...); 1251 1252/* 1253** CAPI3REF: Memory Allocation Routines 1254** 1255** An instance of this object defines the interface between SQLite 1256** and low-level memory allocation routines. 1257** 1258** This object is used in only one place in the SQLite interface. 1259** A pointer to an instance of this object is the argument to 1260** [sqlite3_config()] when the configuration option is 1261** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1262** By creating an instance of this object 1263** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1264** during configuration, an application can specify an alternative 1265** memory allocation subsystem for SQLite to use for all of its 1266** dynamic memory needs. 1267** 1268** Note that SQLite comes with several [built-in memory allocators] 1269** that are perfectly adequate for the overwhelming majority of applications 1270** and that this object is only useful to a tiny minority of applications 1271** with specialized memory allocation requirements. This object is 1272** also used during testing of SQLite in order to specify an alternative 1273** memory allocator that simulates memory out-of-memory conditions in 1274** order to verify that SQLite recovers gracefully from such 1275** conditions. 1276** 1277** The xMalloc, xRealloc, and xFree methods must work like the 1278** malloc(), realloc() and free() functions from the standard C library. 1279** ^SQLite guarantees that the second argument to 1280** xRealloc is always a value returned by a prior call to xRoundup. 1281** 1282** xSize should return the allocated size of a memory allocation 1283** previously obtained from xMalloc or xRealloc. The allocated size 1284** is always at least as big as the requested size but may be larger. 1285** 1286** The xRoundup method returns what would be the allocated size of 1287** a memory allocation given a particular requested size. Most memory 1288** allocators round up memory allocations at least to the next multiple 1289** of 8. Some allocators round up to a larger multiple or to a power of 2. 1290** Every memory allocation request coming in through [sqlite3_malloc()] 1291** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1292** that causes the corresponding memory allocation to fail. 1293** 1294** The xInit method initializes the memory allocator. (For example, 1295** it might allocate any require mutexes or initialize internal data 1296** structures. The xShutdown method is invoked (indirectly) by 1297** [sqlite3_shutdown()] and should deallocate any resources acquired 1298** by xInit. The pAppData pointer is used as the only parameter to 1299** xInit and xShutdown. 1300** 1301** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1302** the xInit method, so the xInit method need not be threadsafe. The 1303** xShutdown method is only called from [sqlite3_shutdown()] so it does 1304** not need to be threadsafe either. For all other methods, SQLite 1305** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1306** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1307** it is by default) and so the methods are automatically serialized. 1308** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1309** methods must be threadsafe or else make their own arrangements for 1310** serialization. 1311** 1312** SQLite will never invoke xInit() more than once without an intervening 1313** call to xShutdown(). 1314*/ 1315typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1316struct sqlite3_mem_methods { 1317 void *(*xMalloc)(int); /* Memory allocation function */ 1318 void (*xFree)(void*); /* Free a prior allocation */ 1319 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1320 int (*xSize)(void*); /* Return the size of an allocation */ 1321 int (*xRoundup)(int); /* Round up request size to allocation size */ 1322 int (*xInit)(void*); /* Initialize the memory allocator */ 1323 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1324 void *pAppData; /* Argument to xInit() and xShutdown() */ 1325}; 1326 1327/* 1328** CAPI3REF: Configuration Options 1329** KEYWORDS: {configuration option} 1330** 1331** These constants are the available integer configuration options that 1332** can be passed as the first argument to the [sqlite3_config()] interface. 1333** 1334** New configuration options may be added in future releases of SQLite. 1335** Existing configuration options might be discontinued. Applications 1336** should check the return code from [sqlite3_config()] to make sure that 1337** the call worked. The [sqlite3_config()] interface will return a 1338** non-zero [error code] if a discontinued or unsupported configuration option 1339** is invoked. 1340** 1341** <dl> 1342** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1343** <dd>There are no arguments to this option. ^This option sets the 1344** [threading mode] to Single-thread. In other words, it disables 1345** all mutexing and puts SQLite into a mode where it can only be used 1346** by a single thread. ^If SQLite is compiled with 1347** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1348** it is not possible to change the [threading mode] from its default 1349** value of Single-thread and so [sqlite3_config()] will return 1350** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1351** configuration option.</dd> 1352** 1353** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1354** <dd>There are no arguments to this option. ^This option sets the 1355** [threading mode] to Multi-thread. In other words, it disables 1356** mutexing on [database connection] and [prepared statement] objects. 1357** The application is responsible for serializing access to 1358** [database connections] and [prepared statements]. But other mutexes 1359** are enabled so that SQLite will be safe to use in a multi-threaded 1360** environment as long as no two threads attempt to use the same 1361** [database connection] at the same time. ^If SQLite is compiled with 1362** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1363** it is not possible to set the Multi-thread [threading mode] and 1364** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1365** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1366** 1367** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1368** <dd>There are no arguments to this option. ^This option sets the 1369** [threading mode] to Serialized. In other words, this option enables 1370** all mutexes including the recursive 1371** mutexes on [database connection] and [prepared statement] objects. 1372** In this mode (which is the default when SQLite is compiled with 1373** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1374** to [database connections] and [prepared statements] so that the 1375** application is free to use the same [database connection] or the 1376** same [prepared statement] in different threads at the same time. 1377** ^If SQLite is compiled with 1378** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1379** it is not possible to set the Serialized [threading mode] and 1380** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1381** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1382** 1383** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1384** <dd> ^(This option takes a single argument which is a pointer to an 1385** instance of the [sqlite3_mem_methods] structure. The argument specifies 1386** alternative low-level memory allocation routines to be used in place of 1387** the memory allocation routines built into SQLite.)^ ^SQLite makes 1388** its own private copy of the content of the [sqlite3_mem_methods] structure 1389** before the [sqlite3_config()] call returns.</dd> 1390** 1391** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1392** <dd> ^(This option takes a single argument which is a pointer to an 1393** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1394** structure is filled with the currently defined memory allocation routines.)^ 1395** This option can be used to overload the default memory allocation 1396** routines with a wrapper that simulations memory allocation failure or 1397** tracks memory usage, for example. </dd> 1398** 1399** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1400** <dd> ^This option takes single argument of type int, interpreted as a 1401** boolean, which enables or disables the collection of memory allocation 1402** statistics. ^(When memory allocation statistics are disabled, the 1403** following SQLite interfaces become non-operational: 1404** <ul> 1405** <li> [sqlite3_memory_used()] 1406** <li> [sqlite3_memory_highwater()] 1407** <li> [sqlite3_soft_heap_limit64()] 1408** <li> [sqlite3_status()] 1409** </ul>)^ 1410** ^Memory allocation statistics are enabled by default unless SQLite is 1411** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1412** allocation statistics are disabled by default. 1413** </dd> 1414** 1415** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1416** <dd> ^This option specifies a static memory buffer that SQLite can use for 1417** scratch memory. There are three arguments: A pointer an 8-byte 1418** aligned memory buffer from which the scratch allocations will be 1419** drawn, the size of each scratch allocation (sz), 1420** and the maximum number of scratch allocations (N). The sz 1421** argument must be a multiple of 16. 1422** The first argument must be a pointer to an 8-byte aligned buffer 1423** of at least sz*N bytes of memory. 1424** ^SQLite will use no more than two scratch buffers per thread. So 1425** N should be set to twice the expected maximum number of threads. 1426** ^SQLite will never require a scratch buffer that is more than 6 1427** times the database page size. ^If SQLite needs needs additional 1428** scratch memory beyond what is provided by this configuration option, then 1429** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1430** 1431** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1432** <dd> ^This option specifies a static memory buffer that SQLite can use for 1433** the database page cache with the default page cache implementation. 1434** This configuration should not be used if an application-define page 1435** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option. 1436** There are three arguments to this option: A pointer to 8-byte aligned 1437** memory, the size of each page buffer (sz), and the number of pages (N). 1438** The sz argument should be the size of the largest database page 1439** (a power of two between 512 and 32768) plus a little extra for each 1440** page header. ^The page header size is 20 to 40 bytes depending on 1441** the host architecture. ^It is harmless, apart from the wasted memory, 1442** to make sz a little too large. The first 1443** argument should point to an allocation of at least sz*N bytes of memory. 1444** ^SQLite will use the memory provided by the first argument to satisfy its 1445** memory needs for the first N pages that it adds to cache. ^If additional 1446** page cache memory is needed beyond what is provided by this option, then 1447** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1448** The pointer in the first argument must 1449** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1450** will be undefined.</dd> 1451** 1452** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1453** <dd> ^This option specifies a static memory buffer that SQLite will use 1454** for all of its dynamic memory allocation needs beyond those provided 1455** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1456** There are three arguments: An 8-byte aligned pointer to the memory, 1457** the number of bytes in the memory buffer, and the minimum allocation size. 1458** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1459** to using its default memory allocator (the system malloc() implementation), 1460** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1461** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1462** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1463** allocator is engaged to handle all of SQLites memory allocation needs. 1464** The first pointer (the memory pointer) must be aligned to an 8-byte 1465** boundary or subsequent behavior of SQLite will be undefined. 1466** The minimum allocation size is capped at 2**12. Reasonable values 1467** for the minimum allocation size are 2**5 through 2**8.</dd> 1468** 1469** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1470** <dd> ^(This option takes a single argument which is a pointer to an 1471** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1472** alternative low-level mutex routines to be used in place 1473** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1474** content of the [sqlite3_mutex_methods] structure before the call to 1475** [sqlite3_config()] returns. ^If SQLite is compiled with 1476** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1477** the entire mutexing subsystem is omitted from the build and hence calls to 1478** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1479** return [SQLITE_ERROR].</dd> 1480** 1481** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1482** <dd> ^(This option takes a single argument which is a pointer to an 1483** instance of the [sqlite3_mutex_methods] structure. The 1484** [sqlite3_mutex_methods] 1485** structure is filled with the currently defined mutex routines.)^ 1486** This option can be used to overload the default mutex allocation 1487** routines with a wrapper used to track mutex usage for performance 1488** profiling or testing, for example. ^If SQLite is compiled with 1489** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1490** the entire mutexing subsystem is omitted from the build and hence calls to 1491** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1492** return [SQLITE_ERROR].</dd> 1493** 1494** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1495** <dd> ^(This option takes two arguments that determine the default 1496** memory allocation for the lookaside memory allocator on each 1497** [database connection]. The first argument is the 1498** size of each lookaside buffer slot and the second is the number of 1499** slots allocated to each database connection.)^ ^(This option sets the 1500** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1501** verb to [sqlite3_db_config()] can be used to change the lookaside 1502** configuration on individual connections.)^ </dd> 1503** 1504** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1505** <dd> ^(This option takes a single argument which is a pointer to 1506** an [sqlite3_pcache_methods2] object. This object specifies the interface 1507** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1508** object and uses it for page cache memory allocations.</dd> 1509** 1510** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1511** <dd> ^(This option takes a single argument which is a pointer to an 1512** [sqlite3_pcache_methods2] object. SQLite copies of the current 1513** page cache implementation into that object.)^ </dd> 1514** 1515** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1516** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1517** function with a call signature of void(*)(void*,int,const char*), 1518** and a pointer to void. ^If the function pointer is not NULL, it is 1519** invoked by [sqlite3_log()] to process each logging event. ^If the 1520** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1521** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1522** passed through as the first parameter to the application-defined logger 1523** function whenever that function is invoked. ^The second parameter to 1524** the logger function is a copy of the first parameter to the corresponding 1525** [sqlite3_log()] call and is intended to be a [result code] or an 1526** [extended result code]. ^The third parameter passed to the logger is 1527** log message after formatting via [sqlite3_snprintf()]. 1528** The SQLite logging interface is not reentrant; the logger function 1529** supplied by the application must not invoke any SQLite interface. 1530** In a multi-threaded application, the application-defined logger 1531** function must be threadsafe. </dd> 1532** 1533** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1534** <dd> This option takes a single argument of type int. If non-zero, then 1535** URI handling is globally enabled. If the parameter is zero, then URI handling 1536** is globally disabled. If URI handling is globally enabled, all filenames 1537** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or 1538** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1539** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1540** connection is opened. If it is globally disabled, filenames are 1541** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1542** database connection is opened. By default, URI handling is globally 1543** disabled. The default value may be changed by compiling with the 1544** [SQLITE_USE_URI] symbol defined. 1545** 1546** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1547** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1548** <dd> These options are obsolete and should not be used by new code. 1549** They are retained for backwards compatibility but are now no-ops. 1550** </dl> 1551*/ 1552#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1553#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1554#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1555#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1556#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1557#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1558#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1559#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1560#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1561#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1562#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1563/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1564#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1565#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1566#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1567#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1568#define SQLITE_CONFIG_URI 17 /* int */ 1569#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1570#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1571 1572/* 1573** CAPI3REF: Database Connection Configuration Options 1574** 1575** These constants are the available integer configuration options that 1576** can be passed as the second argument to the [sqlite3_db_config()] interface. 1577** 1578** New configuration options may be added in future releases of SQLite. 1579** Existing configuration options might be discontinued. Applications 1580** should check the return code from [sqlite3_db_config()] to make sure that 1581** the call worked. ^The [sqlite3_db_config()] interface will return a 1582** non-zero [error code] if a discontinued or unsupported configuration option 1583** is invoked. 1584** 1585** <dl> 1586** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1587** <dd> ^This option takes three additional arguments that determine the 1588** [lookaside memory allocator] configuration for the [database connection]. 1589** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1590** pointer to a memory buffer to use for lookaside memory. 1591** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1592** may be NULL in which case SQLite will allocate the 1593** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1594** size of each lookaside buffer slot. ^The third argument is the number of 1595** slots. The size of the buffer in the first argument must be greater than 1596** or equal to the product of the second and third arguments. The buffer 1597** must be aligned to an 8-byte boundary. ^If the second argument to 1598** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1599** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1600** configuration for a database connection can only be changed when that 1601** connection is not currently using lookaside memory, or in other words 1602** when the "current value" returned by 1603** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1604** Any attempt to change the lookaside memory configuration when lookaside 1605** memory is in use leaves the configuration unchanged and returns 1606** [SQLITE_BUSY].)^</dd> 1607** 1608** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1609** <dd> ^This option is used to enable or disable the enforcement of 1610** [foreign key constraints]. There should be two additional arguments. 1611** The first argument is an integer which is 0 to disable FK enforcement, 1612** positive to enable FK enforcement or negative to leave FK enforcement 1613** unchanged. The second parameter is a pointer to an integer into which 1614** is written 0 or 1 to indicate whether FK enforcement is off or on 1615** following this call. The second parameter may be a NULL pointer, in 1616** which case the FK enforcement setting is not reported back. </dd> 1617** 1618** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1619** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1620** There should be two additional arguments. 1621** The first argument is an integer which is 0 to disable triggers, 1622** positive to enable triggers or negative to leave the setting unchanged. 1623** The second parameter is a pointer to an integer into which 1624** is written 0 or 1 to indicate whether triggers are disabled or enabled 1625** following this call. The second parameter may be a NULL pointer, in 1626** which case the trigger setting is not reported back. </dd> 1627** 1628** </dl> 1629*/ 1630#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1631#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1632#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1633 1634 1635/* 1636** CAPI3REF: Enable Or Disable Extended Result Codes 1637** 1638** ^The sqlite3_extended_result_codes() routine enables or disables the 1639** [extended result codes] feature of SQLite. ^The extended result 1640** codes are disabled by default for historical compatibility. 1641*/ 1642int sqlite3_extended_result_codes(sqlite3*, int onoff); 1643 1644/* 1645** CAPI3REF: Last Insert Rowid 1646** 1647** ^Each entry in an SQLite table has a unique 64-bit signed 1648** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1649** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1650** names are not also used by explicitly declared columns. ^If 1651** the table has a column of type [INTEGER PRIMARY KEY] then that column 1652** is another alias for the rowid. 1653** 1654** ^This routine returns the [rowid] of the most recent 1655** successful [INSERT] into the database from the [database connection] 1656** in the first argument. ^As of SQLite version 3.7.7, this routines 1657** records the last insert rowid of both ordinary tables and [virtual tables]. 1658** ^If no successful [INSERT]s 1659** have ever occurred on that database connection, zero is returned. 1660** 1661** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1662** method, then this routine will return the [rowid] of the inserted 1663** row as long as the trigger or virtual table method is running. 1664** But once the trigger or virtual table method ends, the value returned 1665** by this routine reverts to what it was before the trigger or virtual 1666** table method began.)^ 1667** 1668** ^An [INSERT] that fails due to a constraint violation is not a 1669** successful [INSERT] and does not change the value returned by this 1670** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1671** and INSERT OR ABORT make no changes to the return value of this 1672** routine when their insertion fails. ^(When INSERT OR REPLACE 1673** encounters a constraint violation, it does not fail. The 1674** INSERT continues to completion after deleting rows that caused 1675** the constraint problem so INSERT OR REPLACE will always change 1676** the return value of this interface.)^ 1677** 1678** ^For the purposes of this routine, an [INSERT] is considered to 1679** be successful even if it is subsequently rolled back. 1680** 1681** This function is accessible to SQL statements via the 1682** [last_insert_rowid() SQL function]. 1683** 1684** If a separate thread performs a new [INSERT] on the same 1685** database connection while the [sqlite3_last_insert_rowid()] 1686** function is running and thus changes the last insert [rowid], 1687** then the value returned by [sqlite3_last_insert_rowid()] is 1688** unpredictable and might not equal either the old or the new 1689** last insert [rowid]. 1690*/ 1691sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1692 1693/* 1694** CAPI3REF: Count The Number Of Rows Modified 1695** 1696** ^This function returns the number of database rows that were changed 1697** or inserted or deleted by the most recently completed SQL statement 1698** on the [database connection] specified by the first parameter. 1699** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1700** or [DELETE] statement are counted. Auxiliary changes caused by 1701** triggers or [foreign key actions] are not counted.)^ Use the 1702** [sqlite3_total_changes()] function to find the total number of changes 1703** including changes caused by triggers and foreign key actions. 1704** 1705** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1706** are not counted. Only real table changes are counted. 1707** 1708** ^(A "row change" is a change to a single row of a single table 1709** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1710** are changed as side effects of [REPLACE] constraint resolution, 1711** rollback, ABORT processing, [DROP TABLE], or by any other 1712** mechanisms do not count as direct row changes.)^ 1713** 1714** A "trigger context" is a scope of execution that begins and 1715** ends with the script of a [CREATE TRIGGER | trigger]. 1716** Most SQL statements are 1717** evaluated outside of any trigger. This is the "top level" 1718** trigger context. If a trigger fires from the top level, a 1719** new trigger context is entered for the duration of that one 1720** trigger. Subtriggers create subcontexts for their duration. 1721** 1722** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1723** not create a new trigger context. 1724** 1725** ^This function returns the number of direct row changes in the 1726** most recent INSERT, UPDATE, or DELETE statement within the same 1727** trigger context. 1728** 1729** ^Thus, when called from the top level, this function returns the 1730** number of changes in the most recent INSERT, UPDATE, or DELETE 1731** that also occurred at the top level. ^(Within the body of a trigger, 1732** the sqlite3_changes() interface can be called to find the number of 1733** changes in the most recently completed INSERT, UPDATE, or DELETE 1734** statement within the body of the same trigger. 1735** However, the number returned does not include changes 1736** caused by subtriggers since those have their own context.)^ 1737** 1738** See also the [sqlite3_total_changes()] interface, the 1739** [count_changes pragma], and the [changes() SQL function]. 1740** 1741** If a separate thread makes changes on the same database connection 1742** while [sqlite3_changes()] is running then the value returned 1743** is unpredictable and not meaningful. 1744*/ 1745int sqlite3_changes(sqlite3*); 1746 1747/* 1748** CAPI3REF: Total Number Of Rows Modified 1749** 1750** ^This function returns the number of row changes caused by [INSERT], 1751** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1752** ^(The count returned by sqlite3_total_changes() includes all changes 1753** from all [CREATE TRIGGER | trigger] contexts and changes made by 1754** [foreign key actions]. However, 1755** the count does not include changes used to implement [REPLACE] constraints, 1756** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1757** count does not include rows of views that fire an [INSTEAD OF trigger], 1758** though if the INSTEAD OF trigger makes changes of its own, those changes 1759** are counted.)^ 1760** ^The sqlite3_total_changes() function counts the changes as soon as 1761** the statement that makes them is completed (when the statement handle 1762** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1763** 1764** See also the [sqlite3_changes()] interface, the 1765** [count_changes pragma], and the [total_changes() SQL function]. 1766** 1767** If a separate thread makes changes on the same database connection 1768** while [sqlite3_total_changes()] is running then the value 1769** returned is unpredictable and not meaningful. 1770*/ 1771int sqlite3_total_changes(sqlite3*); 1772 1773/* 1774** CAPI3REF: Interrupt A Long-Running Query 1775** 1776** ^This function causes any pending database operation to abort and 1777** return at its earliest opportunity. This routine is typically 1778** called in response to a user action such as pressing "Cancel" 1779** or Ctrl-C where the user wants a long query operation to halt 1780** immediately. 1781** 1782** ^It is safe to call this routine from a thread different from the 1783** thread that is currently running the database operation. But it 1784** is not safe to call this routine with a [database connection] that 1785** is closed or might close before sqlite3_interrupt() returns. 1786** 1787** ^If an SQL operation is very nearly finished at the time when 1788** sqlite3_interrupt() is called, then it might not have an opportunity 1789** to be interrupted and might continue to completion. 1790** 1791** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1792** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1793** that is inside an explicit transaction, then the entire transaction 1794** will be rolled back automatically. 1795** 1796** ^The sqlite3_interrupt(D) call is in effect until all currently running 1797** SQL statements on [database connection] D complete. ^Any new SQL statements 1798** that are started after the sqlite3_interrupt() call and before the 1799** running statements reaches zero are interrupted as if they had been 1800** running prior to the sqlite3_interrupt() call. ^New SQL statements 1801** that are started after the running statement count reaches zero are 1802** not effected by the sqlite3_interrupt(). 1803** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1804** SQL statements is a no-op and has no effect on SQL statements 1805** that are started after the sqlite3_interrupt() call returns. 1806** 1807** If the database connection closes while [sqlite3_interrupt()] 1808** is running then bad things will likely happen. 1809*/ 1810void sqlite3_interrupt(sqlite3*); 1811 1812/* 1813** CAPI3REF: Determine If An SQL Statement Is Complete 1814** 1815** These routines are useful during command-line input to determine if the 1816** currently entered text seems to form a complete SQL statement or 1817** if additional input is needed before sending the text into 1818** SQLite for parsing. ^These routines return 1 if the input string 1819** appears to be a complete SQL statement. ^A statement is judged to be 1820** complete if it ends with a semicolon token and is not a prefix of a 1821** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1822** string literals or quoted identifier names or comments are not 1823** independent tokens (they are part of the token in which they are 1824** embedded) and thus do not count as a statement terminator. ^Whitespace 1825** and comments that follow the final semicolon are ignored. 1826** 1827** ^These routines return 0 if the statement is incomplete. ^If a 1828** memory allocation fails, then SQLITE_NOMEM is returned. 1829** 1830** ^These routines do not parse the SQL statements thus 1831** will not detect syntactically incorrect SQL. 1832** 1833** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1834** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1835** automatically by sqlite3_complete16(). If that initialization fails, 1836** then the return value from sqlite3_complete16() will be non-zero 1837** regardless of whether or not the input SQL is complete.)^ 1838** 1839** The input to [sqlite3_complete()] must be a zero-terminated 1840** UTF-8 string. 1841** 1842** The input to [sqlite3_complete16()] must be a zero-terminated 1843** UTF-16 string in native byte order. 1844*/ 1845int sqlite3_complete(const char *sql); 1846int sqlite3_complete16(const void *sql); 1847 1848/* 1849** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1850** 1851** ^This routine sets a callback function that might be invoked whenever 1852** an attempt is made to open a database table that another thread 1853** or process has locked. 1854** 1855** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1856** is returned immediately upon encountering the lock. ^If the busy callback 1857** is not NULL, then the callback might be invoked with two arguments. 1858** 1859** ^The first argument to the busy handler is a copy of the void* pointer which 1860** is the third argument to sqlite3_busy_handler(). ^The second argument to 1861** the busy handler callback is the number of times that the busy handler has 1862** been invoked for this locking event. ^If the 1863** busy callback returns 0, then no additional attempts are made to 1864** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1865** ^If the callback returns non-zero, then another attempt 1866** is made to open the database for reading and the cycle repeats. 1867** 1868** The presence of a busy handler does not guarantee that it will be invoked 1869** when there is lock contention. ^If SQLite determines that invoking the busy 1870** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1871** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1872** Consider a scenario where one process is holding a read lock that 1873** it is trying to promote to a reserved lock and 1874** a second process is holding a reserved lock that it is trying 1875** to promote to an exclusive lock. The first process cannot proceed 1876** because it is blocked by the second and the second process cannot 1877** proceed because it is blocked by the first. If both processes 1878** invoke the busy handlers, neither will make any progress. Therefore, 1879** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1880** will induce the first process to release its read lock and allow 1881** the second process to proceed. 1882** 1883** ^The default busy callback is NULL. 1884** 1885** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1886** when SQLite is in the middle of a large transaction where all the 1887** changes will not fit into the in-memory cache. SQLite will 1888** already hold a RESERVED lock on the database file, but it needs 1889** to promote this lock to EXCLUSIVE so that it can spill cache 1890** pages into the database file without harm to concurrent 1891** readers. ^If it is unable to promote the lock, then the in-memory 1892** cache will be left in an inconsistent state and so the error 1893** code is promoted from the relatively benign [SQLITE_BUSY] to 1894** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 1895** forces an automatic rollback of the changes. See the 1896** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1897** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1898** this is important. 1899** 1900** ^(There can only be a single busy handler defined for each 1901** [database connection]. Setting a new busy handler clears any 1902** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 1903** will also set or clear the busy handler. 1904** 1905** The busy callback should not take any actions which modify the 1906** database connection that invoked the busy handler. Any such actions 1907** result in undefined behavior. 1908** 1909** A busy handler must not close the database connection 1910** or [prepared statement] that invoked the busy handler. 1911*/ 1912int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1913 1914/* 1915** CAPI3REF: Set A Busy Timeout 1916** 1917** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1918** for a specified amount of time when a table is locked. ^The handler 1919** will sleep multiple times until at least "ms" milliseconds of sleeping 1920** have accumulated. ^After at least "ms" milliseconds of sleeping, 1921** the handler returns 0 which causes [sqlite3_step()] to return 1922** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1923** 1924** ^Calling this routine with an argument less than or equal to zero 1925** turns off all busy handlers. 1926** 1927** ^(There can only be a single busy handler for a particular 1928** [database connection] any any given moment. If another busy handler 1929** was defined (using [sqlite3_busy_handler()]) prior to calling 1930** this routine, that other busy handler is cleared.)^ 1931*/ 1932int sqlite3_busy_timeout(sqlite3*, int ms); 1933 1934/* 1935** CAPI3REF: Convenience Routines For Running Queries 1936** 1937** This is a legacy interface that is preserved for backwards compatibility. 1938** Use of this interface is not recommended. 1939** 1940** Definition: A <b>result table</b> is memory data structure created by the 1941** [sqlite3_get_table()] interface. A result table records the 1942** complete query results from one or more queries. 1943** 1944** The table conceptually has a number of rows and columns. But 1945** these numbers are not part of the result table itself. These 1946** numbers are obtained separately. Let N be the number of rows 1947** and M be the number of columns. 1948** 1949** A result table is an array of pointers to zero-terminated UTF-8 strings. 1950** There are (N+1)*M elements in the array. The first M pointers point 1951** to zero-terminated strings that contain the names of the columns. 1952** The remaining entries all point to query results. NULL values result 1953** in NULL pointers. All other values are in their UTF-8 zero-terminated 1954** string representation as returned by [sqlite3_column_text()]. 1955** 1956** A result table might consist of one or more memory allocations. 1957** It is not safe to pass a result table directly to [sqlite3_free()]. 1958** A result table should be deallocated using [sqlite3_free_table()]. 1959** 1960** ^(As an example of the result table format, suppose a query result 1961** is as follows: 1962** 1963** <blockquote><pre> 1964** Name | Age 1965** ----------------------- 1966** Alice | 43 1967** Bob | 28 1968** Cindy | 21 1969** </pre></blockquote> 1970** 1971** There are two column (M==2) and three rows (N==3). Thus the 1972** result table has 8 entries. Suppose the result table is stored 1973** in an array names azResult. Then azResult holds this content: 1974** 1975** <blockquote><pre> 1976** azResult[0] = "Name"; 1977** azResult[1] = "Age"; 1978** azResult[2] = "Alice"; 1979** azResult[3] = "43"; 1980** azResult[4] = "Bob"; 1981** azResult[5] = "28"; 1982** azResult[6] = "Cindy"; 1983** azResult[7] = "21"; 1984** </pre></blockquote>)^ 1985** 1986** ^The sqlite3_get_table() function evaluates one or more 1987** semicolon-separated SQL statements in the zero-terminated UTF-8 1988** string of its 2nd parameter and returns a result table to the 1989** pointer given in its 3rd parameter. 1990** 1991** After the application has finished with the result from sqlite3_get_table(), 1992** it must pass the result table pointer to sqlite3_free_table() in order to 1993** release the memory that was malloced. Because of the way the 1994** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1995** function must not try to call [sqlite3_free()] directly. Only 1996** [sqlite3_free_table()] is able to release the memory properly and safely. 1997** 1998** The sqlite3_get_table() interface is implemented as a wrapper around 1999** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2000** to any internal data structures of SQLite. It uses only the public 2001** interface defined here. As a consequence, errors that occur in the 2002** wrapper layer outside of the internal [sqlite3_exec()] call are not 2003** reflected in subsequent calls to [sqlite3_errcode()] or 2004** [sqlite3_errmsg()]. 2005*/ 2006int sqlite3_get_table( 2007 sqlite3 *db, /* An open database */ 2008 const char *zSql, /* SQL to be evaluated */ 2009 char ***pazResult, /* Results of the query */ 2010 int *pnRow, /* Number of result rows written here */ 2011 int *pnColumn, /* Number of result columns written here */ 2012 char **pzErrmsg /* Error msg written here */ 2013); 2014void sqlite3_free_table(char **result); 2015 2016/* 2017** CAPI3REF: Formatted String Printing Functions 2018** 2019** These routines are work-alikes of the "printf()" family of functions 2020** from the standard C library. 2021** 2022** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2023** results into memory obtained from [sqlite3_malloc()]. 2024** The strings returned by these two routines should be 2025** released by [sqlite3_free()]. ^Both routines return a 2026** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2027** memory to hold the resulting string. 2028** 2029** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2030** the standard C library. The result is written into the 2031** buffer supplied as the second parameter whose size is given by 2032** the first parameter. Note that the order of the 2033** first two parameters is reversed from snprintf().)^ This is an 2034** historical accident that cannot be fixed without breaking 2035** backwards compatibility. ^(Note also that sqlite3_snprintf() 2036** returns a pointer to its buffer instead of the number of 2037** characters actually written into the buffer.)^ We admit that 2038** the number of characters written would be a more useful return 2039** value but we cannot change the implementation of sqlite3_snprintf() 2040** now without breaking compatibility. 2041** 2042** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2043** guarantees that the buffer is always zero-terminated. ^The first 2044** parameter "n" is the total size of the buffer, including space for 2045** the zero terminator. So the longest string that can be completely 2046** written will be n-1 characters. 2047** 2048** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2049** 2050** These routines all implement some additional formatting 2051** options that are useful for constructing SQL statements. 2052** All of the usual printf() formatting options apply. In addition, there 2053** is are "%q", "%Q", and "%z" options. 2054** 2055** ^(The %q option works like %s in that it substitutes a nul-terminated 2056** string from the argument list. But %q also doubles every '\'' character. 2057** %q is designed for use inside a string literal.)^ By doubling each '\'' 2058** character it escapes that character and allows it to be inserted into 2059** the string. 2060** 2061** For example, assume the string variable zText contains text as follows: 2062** 2063** <blockquote><pre> 2064** char *zText = "It's a happy day!"; 2065** </pre></blockquote> 2066** 2067** One can use this text in an SQL statement as follows: 2068** 2069** <blockquote><pre> 2070** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2071** sqlite3_exec(db, zSQL, 0, 0, 0); 2072** sqlite3_free(zSQL); 2073** </pre></blockquote> 2074** 2075** Because the %q format string is used, the '\'' character in zText 2076** is escaped and the SQL generated is as follows: 2077** 2078** <blockquote><pre> 2079** INSERT INTO table1 VALUES('It''s a happy day!') 2080** </pre></blockquote> 2081** 2082** This is correct. Had we used %s instead of %q, the generated SQL 2083** would have looked like this: 2084** 2085** <blockquote><pre> 2086** INSERT INTO table1 VALUES('It's a happy day!'); 2087** </pre></blockquote> 2088** 2089** This second example is an SQL syntax error. As a general rule you should 2090** always use %q instead of %s when inserting text into a string literal. 2091** 2092** ^(The %Q option works like %q except it also adds single quotes around 2093** the outside of the total string. Additionally, if the parameter in the 2094** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2095** single quotes).)^ So, for example, one could say: 2096** 2097** <blockquote><pre> 2098** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2099** sqlite3_exec(db, zSQL, 0, 0, 0); 2100** sqlite3_free(zSQL); 2101** </pre></blockquote> 2102** 2103** The code above will render a correct SQL statement in the zSQL 2104** variable even if the zText variable is a NULL pointer. 2105** 2106** ^(The "%z" formatting option works like "%s" but with the 2107** addition that after the string has been read and copied into 2108** the result, [sqlite3_free()] is called on the input string.)^ 2109*/ 2110char *sqlite3_mprintf(const char*,...); 2111char *sqlite3_vmprintf(const char*, va_list); 2112char *sqlite3_snprintf(int,char*,const char*, ...); 2113char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2114 2115/* 2116** CAPI3REF: Memory Allocation Subsystem 2117** 2118** The SQLite core uses these three routines for all of its own 2119** internal memory allocation needs. "Core" in the previous sentence 2120** does not include operating-system specific VFS implementation. The 2121** Windows VFS uses native malloc() and free() for some operations. 2122** 2123** ^The sqlite3_malloc() routine returns a pointer to a block 2124** of memory at least N bytes in length, where N is the parameter. 2125** ^If sqlite3_malloc() is unable to obtain sufficient free 2126** memory, it returns a NULL pointer. ^If the parameter N to 2127** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2128** a NULL pointer. 2129** 2130** ^Calling sqlite3_free() with a pointer previously returned 2131** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2132** that it might be reused. ^The sqlite3_free() routine is 2133** a no-op if is called with a NULL pointer. Passing a NULL pointer 2134** to sqlite3_free() is harmless. After being freed, memory 2135** should neither be read nor written. Even reading previously freed 2136** memory might result in a segmentation fault or other severe error. 2137** Memory corruption, a segmentation fault, or other severe error 2138** might result if sqlite3_free() is called with a non-NULL pointer that 2139** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2140** 2141** ^(The sqlite3_realloc() interface attempts to resize a 2142** prior memory allocation to be at least N bytes, where N is the 2143** second parameter. The memory allocation to be resized is the first 2144** parameter.)^ ^ If the first parameter to sqlite3_realloc() 2145** is a NULL pointer then its behavior is identical to calling 2146** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 2147** ^If the second parameter to sqlite3_realloc() is zero or 2148** negative then the behavior is exactly the same as calling 2149** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 2150** ^sqlite3_realloc() returns a pointer to a memory allocation 2151** of at least N bytes in size or NULL if sufficient memory is unavailable. 2152** ^If M is the size of the prior allocation, then min(N,M) bytes 2153** of the prior allocation are copied into the beginning of buffer returned 2154** by sqlite3_realloc() and the prior allocation is freed. 2155** ^If sqlite3_realloc() returns NULL, then the prior allocation 2156** is not freed. 2157** 2158** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 2159** is always aligned to at least an 8 byte boundary, or to a 2160** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2161** option is used. 2162** 2163** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2164** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2165** implementation of these routines to be omitted. That capability 2166** is no longer provided. Only built-in memory allocators can be used. 2167** 2168** The Windows OS interface layer calls 2169** the system malloc() and free() directly when converting 2170** filenames between the UTF-8 encoding used by SQLite 2171** and whatever filename encoding is used by the particular Windows 2172** installation. Memory allocation errors are detected, but 2173** they are reported back as [SQLITE_CANTOPEN] or 2174** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2175** 2176** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2177** must be either NULL or else pointers obtained from a prior 2178** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2179** not yet been released. 2180** 2181** The application must not read or write any part of 2182** a block of memory after it has been released using 2183** [sqlite3_free()] or [sqlite3_realloc()]. 2184*/ 2185void *sqlite3_malloc(int); 2186void *sqlite3_realloc(void*, int); 2187void sqlite3_free(void*); 2188 2189/* 2190** CAPI3REF: Memory Allocator Statistics 2191** 2192** SQLite provides these two interfaces for reporting on the status 2193** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2194** routines, which form the built-in memory allocation subsystem. 2195** 2196** ^The [sqlite3_memory_used()] routine returns the number of bytes 2197** of memory currently outstanding (malloced but not freed). 2198** ^The [sqlite3_memory_highwater()] routine returns the maximum 2199** value of [sqlite3_memory_used()] since the high-water mark 2200** was last reset. ^The values returned by [sqlite3_memory_used()] and 2201** [sqlite3_memory_highwater()] include any overhead 2202** added by SQLite in its implementation of [sqlite3_malloc()], 2203** but not overhead added by the any underlying system library 2204** routines that [sqlite3_malloc()] may call. 2205** 2206** ^The memory high-water mark is reset to the current value of 2207** [sqlite3_memory_used()] if and only if the parameter to 2208** [sqlite3_memory_highwater()] is true. ^The value returned 2209** by [sqlite3_memory_highwater(1)] is the high-water mark 2210** prior to the reset. 2211*/ 2212sqlite3_int64 sqlite3_memory_used(void); 2213sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2214 2215/* 2216** CAPI3REF: Pseudo-Random Number Generator 2217** 2218** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2219** select random [ROWID | ROWIDs] when inserting new records into a table that 2220** already uses the largest possible [ROWID]. The PRNG is also used for 2221** the build-in random() and randomblob() SQL functions. This interface allows 2222** applications to access the same PRNG for other purposes. 2223** 2224** ^A call to this routine stores N bytes of randomness into buffer P. 2225** 2226** ^The first time this routine is invoked (either internally or by 2227** the application) the PRNG is seeded using randomness obtained 2228** from the xRandomness method of the default [sqlite3_vfs] object. 2229** ^On all subsequent invocations, the pseudo-randomness is generated 2230** internally and without recourse to the [sqlite3_vfs] xRandomness 2231** method. 2232*/ 2233void sqlite3_randomness(int N, void *P); 2234 2235/* 2236** CAPI3REF: Compile-Time Authorization Callbacks 2237** 2238** ^This routine registers an authorizer callback with a particular 2239** [database connection], supplied in the first argument. 2240** ^The authorizer callback is invoked as SQL statements are being compiled 2241** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2242** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2243** points during the compilation process, as logic is being created 2244** to perform various actions, the authorizer callback is invoked to 2245** see if those actions are allowed. ^The authorizer callback should 2246** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2247** specific action but allow the SQL statement to continue to be 2248** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2249** rejected with an error. ^If the authorizer callback returns 2250** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2251** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2252** the authorizer will fail with an error message. 2253** 2254** When the callback returns [SQLITE_OK], that means the operation 2255** requested is ok. ^When the callback returns [SQLITE_DENY], the 2256** [sqlite3_prepare_v2()] or equivalent call that triggered the 2257** authorizer will fail with an error message explaining that 2258** access is denied. 2259** 2260** ^The first parameter to the authorizer callback is a copy of the third 2261** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2262** to the callback is an integer [SQLITE_COPY | action code] that specifies 2263** the particular action to be authorized. ^The third through sixth parameters 2264** to the callback are zero-terminated strings that contain additional 2265** details about the action to be authorized. 2266** 2267** ^If the action code is [SQLITE_READ] 2268** and the callback returns [SQLITE_IGNORE] then the 2269** [prepared statement] statement is constructed to substitute 2270** a NULL value in place of the table column that would have 2271** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2272** return can be used to deny an untrusted user access to individual 2273** columns of a table. 2274** ^If the action code is [SQLITE_DELETE] and the callback returns 2275** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2276** [truncate optimization] is disabled and all rows are deleted individually. 2277** 2278** An authorizer is used when [sqlite3_prepare | preparing] 2279** SQL statements from an untrusted source, to ensure that the SQL statements 2280** do not try to access data they are not allowed to see, or that they do not 2281** try to execute malicious statements that damage the database. For 2282** example, an application may allow a user to enter arbitrary 2283** SQL queries for evaluation by a database. But the application does 2284** not want the user to be able to make arbitrary changes to the 2285** database. An authorizer could then be put in place while the 2286** user-entered SQL is being [sqlite3_prepare | prepared] that 2287** disallows everything except [SELECT] statements. 2288** 2289** Applications that need to process SQL from untrusted sources 2290** might also consider lowering resource limits using [sqlite3_limit()] 2291** and limiting database size using the [max_page_count] [PRAGMA] 2292** in addition to using an authorizer. 2293** 2294** ^(Only a single authorizer can be in place on a database connection 2295** at a time. Each call to sqlite3_set_authorizer overrides the 2296** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2297** The authorizer is disabled by default. 2298** 2299** The authorizer callback must not do anything that will modify 2300** the database connection that invoked the authorizer callback. 2301** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2302** database connections for the meaning of "modify" in this paragraph. 2303** 2304** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2305** statement might be re-prepared during [sqlite3_step()] due to a 2306** schema change. Hence, the application should ensure that the 2307** correct authorizer callback remains in place during the [sqlite3_step()]. 2308** 2309** ^Note that the authorizer callback is invoked only during 2310** [sqlite3_prepare()] or its variants. Authorization is not 2311** performed during statement evaluation in [sqlite3_step()], unless 2312** as stated in the previous paragraph, sqlite3_step() invokes 2313** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2314*/ 2315int sqlite3_set_authorizer( 2316 sqlite3*, 2317 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2318 void *pUserData 2319); 2320 2321/* 2322** CAPI3REF: Authorizer Return Codes 2323** 2324** The [sqlite3_set_authorizer | authorizer callback function] must 2325** return either [SQLITE_OK] or one of these two constants in order 2326** to signal SQLite whether or not the action is permitted. See the 2327** [sqlite3_set_authorizer | authorizer documentation] for additional 2328** information. 2329** 2330** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code] 2331** from the [sqlite3_vtab_on_conflict()] interface. 2332*/ 2333#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2334#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2335 2336/* 2337** CAPI3REF: Authorizer Action Codes 2338** 2339** The [sqlite3_set_authorizer()] interface registers a callback function 2340** that is invoked to authorize certain SQL statement actions. The 2341** second parameter to the callback is an integer code that specifies 2342** what action is being authorized. These are the integer action codes that 2343** the authorizer callback may be passed. 2344** 2345** These action code values signify what kind of operation is to be 2346** authorized. The 3rd and 4th parameters to the authorization 2347** callback function will be parameters or NULL depending on which of these 2348** codes is used as the second parameter. ^(The 5th parameter to the 2349** authorizer callback is the name of the database ("main", "temp", 2350** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2351** is the name of the inner-most trigger or view that is responsible for 2352** the access attempt or NULL if this access attempt is directly from 2353** top-level SQL code. 2354*/ 2355/******************************************* 3rd ************ 4th ***********/ 2356#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2357#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2358#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2359#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2360#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2361#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2362#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2363#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2364#define SQLITE_DELETE 9 /* Table Name NULL */ 2365#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2366#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2367#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2368#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2369#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2370#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2371#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2372#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2373#define SQLITE_INSERT 18 /* Table Name NULL */ 2374#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2375#define SQLITE_READ 20 /* Table Name Column Name */ 2376#define SQLITE_SELECT 21 /* NULL NULL */ 2377#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2378#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2379#define SQLITE_ATTACH 24 /* Filename NULL */ 2380#define SQLITE_DETACH 25 /* Database Name NULL */ 2381#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2382#define SQLITE_REINDEX 27 /* Index Name NULL */ 2383#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2384#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2385#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2386#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2387#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2388#define SQLITE_COPY 0 /* No longer used */ 2389 2390/* 2391** CAPI3REF: Tracing And Profiling Functions 2392** 2393** These routines register callback functions that can be used for 2394** tracing and profiling the execution of SQL statements. 2395** 2396** ^The callback function registered by sqlite3_trace() is invoked at 2397** various times when an SQL statement is being run by [sqlite3_step()]. 2398** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2399** SQL statement text as the statement first begins executing. 2400** ^(Additional sqlite3_trace() callbacks might occur 2401** as each triggered subprogram is entered. The callbacks for triggers 2402** contain a UTF-8 SQL comment that identifies the trigger.)^ 2403** 2404** ^The callback function registered by sqlite3_profile() is invoked 2405** as each SQL statement finishes. ^The profile callback contains 2406** the original statement text and an estimate of wall-clock time 2407** of how long that statement took to run. ^The profile callback 2408** time is in units of nanoseconds, however the current implementation 2409** is only capable of millisecond resolution so the six least significant 2410** digits in the time are meaningless. Future versions of SQLite 2411** might provide greater resolution on the profiler callback. The 2412** sqlite3_profile() function is considered experimental and is 2413** subject to change in future versions of SQLite. 2414*/ 2415void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2416SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2417 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2418 2419/* 2420** CAPI3REF: Query Progress Callbacks 2421** 2422** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2423** function X to be invoked periodically during long running calls to 2424** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2425** database connection D. An example use for this 2426** interface is to keep a GUI updated during a large query. 2427** 2428** ^The parameter P is passed through as the only parameter to the 2429** callback function X. ^The parameter N is the number of 2430** [virtual machine instructions] that are evaluated between successive 2431** invocations of the callback X. 2432** 2433** ^Only a single progress handler may be defined at one time per 2434** [database connection]; setting a new progress handler cancels the 2435** old one. ^Setting parameter X to NULL disables the progress handler. 2436** ^The progress handler is also disabled by setting N to a value less 2437** than 1. 2438** 2439** ^If the progress callback returns non-zero, the operation is 2440** interrupted. This feature can be used to implement a 2441** "Cancel" button on a GUI progress dialog box. 2442** 2443** The progress handler callback must not do anything that will modify 2444** the database connection that invoked the progress handler. 2445** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2446** database connections for the meaning of "modify" in this paragraph. 2447** 2448*/ 2449void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2450 2451/* 2452** CAPI3REF: Opening A New Database Connection 2453** 2454** ^These routines open an SQLite database file as specified by the 2455** filename argument. ^The filename argument is interpreted as UTF-8 for 2456** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2457** order for sqlite3_open16(). ^(A [database connection] handle is usually 2458** returned in *ppDb, even if an error occurs. The only exception is that 2459** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2460** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2461** object.)^ ^(If the database is opened (and/or created) successfully, then 2462** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2463** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2464** an English language description of the error following a failure of any 2465** of the sqlite3_open() routines. 2466** 2467** ^The default encoding for the database will be UTF-8 if 2468** sqlite3_open() or sqlite3_open_v2() is called and 2469** UTF-16 in the native byte order if sqlite3_open16() is used. 2470** 2471** Whether or not an error occurs when it is opened, resources 2472** associated with the [database connection] handle should be released by 2473** passing it to [sqlite3_close()] when it is no longer required. 2474** 2475** The sqlite3_open_v2() interface works like sqlite3_open() 2476** except that it accepts two additional parameters for additional control 2477** over the new database connection. ^(The flags parameter to 2478** sqlite3_open_v2() can take one of 2479** the following three values, optionally combined with the 2480** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2481** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2482** 2483** <dl> 2484** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2485** <dd>The database is opened in read-only mode. If the database does not 2486** already exist, an error is returned.</dd>)^ 2487** 2488** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2489** <dd>The database is opened for reading and writing if possible, or reading 2490** only if the file is write protected by the operating system. In either 2491** case the database must already exist, otherwise an error is returned.</dd>)^ 2492** 2493** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2494** <dd>The database is opened for reading and writing, and is created if 2495** it does not already exist. This is the behavior that is always used for 2496** sqlite3_open() and sqlite3_open16().</dd>)^ 2497** </dl> 2498** 2499** If the 3rd parameter to sqlite3_open_v2() is not one of the 2500** combinations shown above optionally combined with other 2501** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2502** then the behavior is undefined. 2503** 2504** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2505** opens in the multi-thread [threading mode] as long as the single-thread 2506** mode has not been set at compile-time or start-time. ^If the 2507** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2508** in the serialized [threading mode] unless single-thread was 2509** previously selected at compile-time or start-time. 2510** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2511** eligible to use [shared cache mode], regardless of whether or not shared 2512** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2513** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2514** participate in [shared cache mode] even if it is enabled. 2515** 2516** ^The fourth parameter to sqlite3_open_v2() is the name of the 2517** [sqlite3_vfs] object that defines the operating system interface that 2518** the new database connection should use. ^If the fourth parameter is 2519** a NULL pointer then the default [sqlite3_vfs] object is used. 2520** 2521** ^If the filename is ":memory:", then a private, temporary in-memory database 2522** is created for the connection. ^This in-memory database will vanish when 2523** the database connection is closed. Future versions of SQLite might 2524** make use of additional special filenames that begin with the ":" character. 2525** It is recommended that when a database filename actually does begin with 2526** a ":" character you should prefix the filename with a pathname such as 2527** "./" to avoid ambiguity. 2528** 2529** ^If the filename is an empty string, then a private, temporary 2530** on-disk database will be created. ^This private database will be 2531** automatically deleted as soon as the database connection is closed. 2532** 2533** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2534** 2535** ^If [URI filename] interpretation is enabled, and the filename argument 2536** begins with "file:", then the filename is interpreted as a URI. ^URI 2537** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2538** set in the fourth argument to sqlite3_open_v2(), or if it has 2539** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2540** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2541** As of SQLite version 3.7.7, URI filename interpretation is turned off 2542** by default, but future releases of SQLite might enable URI filename 2543** interpretation by default. See "[URI filenames]" for additional 2544** information. 2545** 2546** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2547** authority, then it must be either an empty string or the string 2548** "localhost". ^If the authority is not an empty string or "localhost", an 2549** error is returned to the caller. ^The fragment component of a URI, if 2550** present, is ignored. 2551** 2552** ^SQLite uses the path component of the URI as the name of the disk file 2553** which contains the database. ^If the path begins with a '/' character, 2554** then it is interpreted as an absolute path. ^If the path does not begin 2555** with a '/' (meaning that the authority section is omitted from the URI) 2556** then the path is interpreted as a relative path. 2557** ^On windows, the first component of an absolute path 2558** is a drive specification (e.g. "C:"). 2559** 2560** [[core URI query parameters]] 2561** The query component of a URI may contain parameters that are interpreted 2562** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2563** SQLite interprets the following three query parameters: 2564** 2565** <ul> 2566** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2567** a VFS object that provides the operating system interface that should 2568** be used to access the database file on disk. ^If this option is set to 2569** an empty string the default VFS object is used. ^Specifying an unknown 2570** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2571** present, then the VFS specified by the option takes precedence over 2572** the value passed as the fourth parameter to sqlite3_open_v2(). 2573** 2574** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 2575** "rwc", or "memory". Attempting to set it to any other value is 2576** an error)^. 2577** ^If "ro" is specified, then the database is opened for read-only 2578** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2579** third argument to sqlite3_prepare_v2(). ^If the mode option is set to 2580** "rw", then the database is opened for read-write (but not create) 2581** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2582** been set. ^Value "rwc" is equivalent to setting both 2583** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 2584** set to "memory" then a pure [in-memory database] that never reads 2585** or writes from disk is used. ^It is an error to specify a value for 2586** the mode parameter that is less restrictive than that specified by 2587** the flags passed in the third parameter to sqlite3_open_v2(). 2588** 2589** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2590** "private". ^Setting it to "shared" is equivalent to setting the 2591** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2592** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2593** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2594** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2595** a URI filename, its value overrides any behaviour requested by setting 2596** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2597** </ul> 2598** 2599** ^Specifying an unknown parameter in the query component of a URI is not an 2600** error. Future versions of SQLite might understand additional query 2601** parameters. See "[query parameters with special meaning to SQLite]" for 2602** additional information. 2603** 2604** [[URI filename examples]] <h3>URI filename examples</h3> 2605** 2606** <table border="1" align=center cellpadding=5> 2607** <tr><th> URI filenames <th> Results 2608** <tr><td> file:data.db <td> 2609** Open the file "data.db" in the current directory. 2610** <tr><td> file:/home/fred/data.db<br> 2611** file:///home/fred/data.db <br> 2612** file://localhost/home/fred/data.db <br> <td> 2613** Open the database file "/home/fred/data.db". 2614** <tr><td> file://darkstar/home/fred/data.db <td> 2615** An error. "darkstar" is not a recognized authority. 2616** <tr><td style="white-space:nowrap"> 2617** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2618** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2619** C:. Note that the %20 escaping in this example is not strictly 2620** necessary - space characters can be used literally 2621** in URI filenames. 2622** <tr><td> file:data.db?mode=ro&cache=private <td> 2623** Open file "data.db" in the current directory for read-only access. 2624** Regardless of whether or not shared-cache mode is enabled by 2625** default, use a private cache. 2626** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td> 2627** Open file "/home/fred/data.db". Use the special VFS "unix-nolock". 2628** <tr><td> file:data.db?mode=readonly <td> 2629** An error. "readonly" is not a valid option for the "mode" parameter. 2630** </table> 2631** 2632** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2633** query components of a URI. A hexadecimal escape sequence consists of a 2634** percent sign - "%" - followed by exactly two hexadecimal digits 2635** specifying an octet value. ^Before the path or query components of a 2636** URI filename are interpreted, they are encoded using UTF-8 and all 2637** hexadecimal escape sequences replaced by a single byte containing the 2638** corresponding octet. If this process generates an invalid UTF-8 encoding, 2639** the results are undefined. 2640** 2641** <b>Note to Windows users:</b> The encoding used for the filename argument 2642** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2643** codepage is currently defined. Filenames containing international 2644** characters must be converted to UTF-8 prior to passing them into 2645** sqlite3_open() or sqlite3_open_v2(). 2646*/ 2647int sqlite3_open( 2648 const char *filename, /* Database filename (UTF-8) */ 2649 sqlite3 **ppDb /* OUT: SQLite db handle */ 2650); 2651int sqlite3_open16( 2652 const void *filename, /* Database filename (UTF-16) */ 2653 sqlite3 **ppDb /* OUT: SQLite db handle */ 2654); 2655int sqlite3_open_v2( 2656 const char *filename, /* Database filename (UTF-8) */ 2657 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2658 int flags, /* Flags */ 2659 const char *zVfs /* Name of VFS module to use */ 2660); 2661 2662/* 2663** CAPI3REF: Obtain Values For URI Parameters 2664** 2665** These are utility routines, useful to VFS implementations, that check 2666** to see if a database file was a URI that contained a specific query 2667** parameter, and if so obtains the value of that query parameter. 2668** 2669** If F is the database filename pointer passed into the xOpen() method of 2670** a VFS implementation when the flags parameter to xOpen() has one or 2671** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 2672** P is the name of the query parameter, then 2673** sqlite3_uri_parameter(F,P) returns the value of the P 2674** parameter if it exists or a NULL pointer if P does not appear as a 2675** query parameter on F. If P is a query parameter of F 2676** has no explicit value, then sqlite3_uri_parameter(F,P) returns 2677** a pointer to an empty string. 2678** 2679** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 2680** parameter and returns true (1) or false (0) according to the value 2681** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 2682** value of query parameter P is one of "yes", "true", or "on" in any 2683** case or if the value begins with a non-zero number. The 2684** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 2685** query parameter P is one of "no", "false", or "off" in any case or 2686** if the value begins with a numeric zero. If P is not a query 2687** parameter on F or if the value of P is does not match any of the 2688** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 2689** 2690** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 2691** 64-bit signed integer and returns that integer, or D if P does not 2692** exist. If the value of P is something other than an integer, then 2693** zero is returned. 2694** 2695** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 2696** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 2697** is not a database file pathname pointer that SQLite passed into the xOpen 2698** VFS method, then the behavior of this routine is undefined and probably 2699** undesirable. 2700*/ 2701const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 2702int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 2703sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 2704 2705 2706/* 2707** CAPI3REF: Error Codes And Messages 2708** 2709** ^The sqlite3_errcode() interface returns the numeric [result code] or 2710** [extended result code] for the most recent failed sqlite3_* API call 2711** associated with a [database connection]. If a prior API call failed 2712** but the most recent API call succeeded, the return value from 2713** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2714** interface is the same except that it always returns the 2715** [extended result code] even when extended result codes are 2716** disabled. 2717** 2718** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2719** text that describes the error, as either UTF-8 or UTF-16 respectively. 2720** ^(Memory to hold the error message string is managed internally. 2721** The application does not need to worry about freeing the result. 2722** However, the error string might be overwritten or deallocated by 2723** subsequent calls to other SQLite interface functions.)^ 2724** 2725** When the serialized [threading mode] is in use, it might be the 2726** case that a second error occurs on a separate thread in between 2727** the time of the first error and the call to these interfaces. 2728** When that happens, the second error will be reported since these 2729** interfaces always report the most recent result. To avoid 2730** this, each thread can obtain exclusive use of the [database connection] D 2731** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2732** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2733** all calls to the interfaces listed here are completed. 2734** 2735** If an interface fails with SQLITE_MISUSE, that means the interface 2736** was invoked incorrectly by the application. In that case, the 2737** error code and message may or may not be set. 2738*/ 2739int sqlite3_errcode(sqlite3 *db); 2740int sqlite3_extended_errcode(sqlite3 *db); 2741const char *sqlite3_errmsg(sqlite3*); 2742const void *sqlite3_errmsg16(sqlite3*); 2743 2744/* 2745** CAPI3REF: SQL Statement Object 2746** KEYWORDS: {prepared statement} {prepared statements} 2747** 2748** An instance of this object represents a single SQL statement. 2749** This object is variously known as a "prepared statement" or a 2750** "compiled SQL statement" or simply as a "statement". 2751** 2752** The life of a statement object goes something like this: 2753** 2754** <ol> 2755** <li> Create the object using [sqlite3_prepare_v2()] or a related 2756** function. 2757** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2758** interfaces. 2759** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2760** <li> Reset the statement using [sqlite3_reset()] then go back 2761** to step 2. Do this zero or more times. 2762** <li> Destroy the object using [sqlite3_finalize()]. 2763** </ol> 2764** 2765** Refer to documentation on individual methods above for additional 2766** information. 2767*/ 2768typedef struct sqlite3_stmt sqlite3_stmt; 2769 2770/* 2771** CAPI3REF: Run-time Limits 2772** 2773** ^(This interface allows the size of various constructs to be limited 2774** on a connection by connection basis. The first parameter is the 2775** [database connection] whose limit is to be set or queried. The 2776** second parameter is one of the [limit categories] that define a 2777** class of constructs to be size limited. The third parameter is the 2778** new limit for that construct.)^ 2779** 2780** ^If the new limit is a negative number, the limit is unchanged. 2781** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 2782** [limits | hard upper bound] 2783** set at compile-time by a C preprocessor macro called 2784** [limits | SQLITE_MAX_<i>NAME</i>]. 2785** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2786** ^Attempts to increase a limit above its hard upper bound are 2787** silently truncated to the hard upper bound. 2788** 2789** ^Regardless of whether or not the limit was changed, the 2790** [sqlite3_limit()] interface returns the prior value of the limit. 2791** ^Hence, to find the current value of a limit without changing it, 2792** simply invoke this interface with the third parameter set to -1. 2793** 2794** Run-time limits are intended for use in applications that manage 2795** both their own internal database and also databases that are controlled 2796** by untrusted external sources. An example application might be a 2797** web browser that has its own databases for storing history and 2798** separate databases controlled by JavaScript applications downloaded 2799** off the Internet. The internal databases can be given the 2800** large, default limits. Databases managed by external sources can 2801** be given much smaller limits designed to prevent a denial of service 2802** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2803** interface to further control untrusted SQL. The size of the database 2804** created by an untrusted script can be contained using the 2805** [max_page_count] [PRAGMA]. 2806** 2807** New run-time limit categories may be added in future releases. 2808*/ 2809int sqlite3_limit(sqlite3*, int id, int newVal); 2810 2811/* 2812** CAPI3REF: Run-Time Limit Categories 2813** KEYWORDS: {limit category} {*limit categories} 2814** 2815** These constants define various performance limits 2816** that can be lowered at run-time using [sqlite3_limit()]. 2817** The synopsis of the meanings of the various limits is shown below. 2818** Additional information is available at [limits | Limits in SQLite]. 2819** 2820** <dl> 2821** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2822** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 2823** 2824** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2825** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2826** 2827** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2828** <dd>The maximum number of columns in a table definition or in the 2829** result set of a [SELECT] or the maximum number of columns in an index 2830** or in an ORDER BY or GROUP BY clause.</dd>)^ 2831** 2832** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2833** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2834** 2835** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2836** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2837** 2838** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2839** <dd>The maximum number of instructions in a virtual machine program 2840** used to implement an SQL statement. This limit is not currently 2841** enforced, though that might be added in some future release of 2842** SQLite.</dd>)^ 2843** 2844** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2845** <dd>The maximum number of arguments on a function.</dd>)^ 2846** 2847** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2848** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2849** 2850** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 2851** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2852** <dd>The maximum length of the pattern argument to the [LIKE] or 2853** [GLOB] operators.</dd>)^ 2854** 2855** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 2856** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2857** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 2858** 2859** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2860** <dd>The maximum depth of recursion for triggers.</dd>)^ 2861** </dl> 2862*/ 2863#define SQLITE_LIMIT_LENGTH 0 2864#define SQLITE_LIMIT_SQL_LENGTH 1 2865#define SQLITE_LIMIT_COLUMN 2 2866#define SQLITE_LIMIT_EXPR_DEPTH 3 2867#define SQLITE_LIMIT_COMPOUND_SELECT 4 2868#define SQLITE_LIMIT_VDBE_OP 5 2869#define SQLITE_LIMIT_FUNCTION_ARG 6 2870#define SQLITE_LIMIT_ATTACHED 7 2871#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2872#define SQLITE_LIMIT_VARIABLE_NUMBER 9 2873#define SQLITE_LIMIT_TRIGGER_DEPTH 10 2874 2875/* 2876** CAPI3REF: Compiling An SQL Statement 2877** KEYWORDS: {SQL statement compiler} 2878** 2879** To execute an SQL query, it must first be compiled into a byte-code 2880** program using one of these routines. 2881** 2882** The first argument, "db", is a [database connection] obtained from a 2883** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2884** [sqlite3_open16()]. The database connection must not have been closed. 2885** 2886** The second argument, "zSql", is the statement to be compiled, encoded 2887** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2888** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2889** use UTF-16. 2890** 2891** ^If the nByte argument is less than zero, then zSql is read up to the 2892** first zero terminator. ^If nByte is non-negative, then it is the maximum 2893** number of bytes read from zSql. ^When nByte is non-negative, the 2894** zSql string ends at either the first '\000' or '\u0000' character or 2895** the nByte-th byte, whichever comes first. If the caller knows 2896** that the supplied string is nul-terminated, then there is a small 2897** performance advantage to be gained by passing an nByte parameter that 2898** is equal to the number of bytes in the input string <i>including</i> 2899** the nul-terminator bytes as this saves SQLite from having to 2900** make a copy of the input string. 2901** 2902** ^If pzTail is not NULL then *pzTail is made to point to the first byte 2903** past the end of the first SQL statement in zSql. These routines only 2904** compile the first statement in zSql, so *pzTail is left pointing to 2905** what remains uncompiled. 2906** 2907** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 2908** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 2909** to NULL. ^If the input text contains no SQL (if the input is an empty 2910** string or a comment) then *ppStmt is set to NULL. 2911** The calling procedure is responsible for deleting the compiled 2912** SQL statement using [sqlite3_finalize()] after it has finished with it. 2913** ppStmt may not be NULL. 2914** 2915** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 2916** otherwise an [error code] is returned. 2917** 2918** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2919** recommended for all new programs. The two older interfaces are retained 2920** for backwards compatibility, but their use is discouraged. 2921** ^In the "v2" interfaces, the prepared statement 2922** that is returned (the [sqlite3_stmt] object) contains a copy of the 2923** original SQL text. This causes the [sqlite3_step()] interface to 2924** behave differently in three ways: 2925** 2926** <ol> 2927** <li> 2928** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2929** always used to do, [sqlite3_step()] will automatically recompile the SQL 2930** statement and try to run it again. 2931** </li> 2932** 2933** <li> 2934** ^When an error occurs, [sqlite3_step()] will return one of the detailed 2935** [error codes] or [extended error codes]. ^The legacy behavior was that 2936** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2937** and the application would have to make a second call to [sqlite3_reset()] 2938** in order to find the underlying cause of the problem. With the "v2" prepare 2939** interfaces, the underlying reason for the error is returned immediately. 2940** </li> 2941** 2942** <li> 2943** ^If the specific value bound to [parameter | host parameter] in the 2944** WHERE clause might influence the choice of query plan for a statement, 2945** then the statement will be automatically recompiled, as if there had been 2946** a schema change, on the first [sqlite3_step()] call following any change 2947** to the [sqlite3_bind_text | bindings] of that [parameter]. 2948** ^The specific value of WHERE-clause [parameter] might influence the 2949** choice of query plan if the parameter is the left-hand side of a [LIKE] 2950** or [GLOB] operator or if the parameter is compared to an indexed column 2951** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 2952** the 2953** </li> 2954** </ol> 2955*/ 2956int sqlite3_prepare( 2957 sqlite3 *db, /* Database handle */ 2958 const char *zSql, /* SQL statement, UTF-8 encoded */ 2959 int nByte, /* Maximum length of zSql in bytes. */ 2960 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2961 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2962); 2963int sqlite3_prepare_v2( 2964 sqlite3 *db, /* Database handle */ 2965 const char *zSql, /* SQL statement, UTF-8 encoded */ 2966 int nByte, /* Maximum length of zSql in bytes. */ 2967 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2968 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2969); 2970int sqlite3_prepare16( 2971 sqlite3 *db, /* Database handle */ 2972 const void *zSql, /* SQL statement, UTF-16 encoded */ 2973 int nByte, /* Maximum length of zSql in bytes. */ 2974 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2975 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2976); 2977int sqlite3_prepare16_v2( 2978 sqlite3 *db, /* Database handle */ 2979 const void *zSql, /* SQL statement, UTF-16 encoded */ 2980 int nByte, /* Maximum length of zSql in bytes. */ 2981 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2982 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2983); 2984 2985/* 2986** CAPI3REF: Retrieving Statement SQL 2987** 2988** ^This interface can be used to retrieve a saved copy of the original 2989** SQL text used to create a [prepared statement] if that statement was 2990** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2991*/ 2992const char *sqlite3_sql(sqlite3_stmt *pStmt); 2993 2994/* 2995** CAPI3REF: Determine If An SQL Statement Writes The Database 2996** 2997** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 2998** and only if the [prepared statement] X makes no direct changes to 2999** the content of the database file. 3000** 3001** Note that [application-defined SQL functions] or 3002** [virtual tables] might change the database indirectly as a side effect. 3003** ^(For example, if an application defines a function "eval()" that 3004** calls [sqlite3_exec()], then the following SQL statement would 3005** change the database file through side-effects: 3006** 3007** <blockquote><pre> 3008** SELECT eval('DELETE FROM t1') FROM t2; 3009** </pre></blockquote> 3010** 3011** But because the [SELECT] statement does not change the database file 3012** directly, sqlite3_stmt_readonly() would still return true.)^ 3013** 3014** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3015** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3016** since the statements themselves do not actually modify the database but 3017** rather they control the timing of when other statements modify the 3018** database. ^The [ATTACH] and [DETACH] statements also cause 3019** sqlite3_stmt_readonly() to return true since, while those statements 3020** change the configuration of a database connection, they do not make 3021** changes to the content of the database files on disk. 3022*/ 3023int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3024 3025/* 3026** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3027** 3028** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3029** [prepared statement] S has been stepped at least once using 3030** [sqlite3_step(S)] but has not run to completion and/or has not 3031** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3032** interface returns false if S is a NULL pointer. If S is not a 3033** NULL pointer and is not a pointer to a valid [prepared statement] 3034** object, then the behavior is undefined and probably undesirable. 3035** 3036** This interface can be used in combination [sqlite3_next_stmt()] 3037** to locate all prepared statements associated with a database 3038** connection that are in need of being reset. This can be used, 3039** for example, in diagnostic routines to search for prepared 3040** statements that are holding a transaction open. 3041*/ 3042int sqlite3_stmt_busy(sqlite3_stmt*); 3043 3044/* 3045** CAPI3REF: Dynamically Typed Value Object 3046** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3047** 3048** SQLite uses the sqlite3_value object to represent all values 3049** that can be stored in a database table. SQLite uses dynamic typing 3050** for the values it stores. ^Values stored in sqlite3_value objects 3051** can be integers, floating point values, strings, BLOBs, or NULL. 3052** 3053** An sqlite3_value object may be either "protected" or "unprotected". 3054** Some interfaces require a protected sqlite3_value. Other interfaces 3055** will accept either a protected or an unprotected sqlite3_value. 3056** Every interface that accepts sqlite3_value arguments specifies 3057** whether or not it requires a protected sqlite3_value. 3058** 3059** The terms "protected" and "unprotected" refer to whether or not 3060** a mutex is held. An internal mutex is held for a protected 3061** sqlite3_value object but no mutex is held for an unprotected 3062** sqlite3_value object. If SQLite is compiled to be single-threaded 3063** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3064** or if SQLite is run in one of reduced mutex modes 3065** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3066** then there is no distinction between protected and unprotected 3067** sqlite3_value objects and they can be used interchangeably. However, 3068** for maximum code portability it is recommended that applications 3069** still make the distinction between protected and unprotected 3070** sqlite3_value objects even when not strictly required. 3071** 3072** ^The sqlite3_value objects that are passed as parameters into the 3073** implementation of [application-defined SQL functions] are protected. 3074** ^The sqlite3_value object returned by 3075** [sqlite3_column_value()] is unprotected. 3076** Unprotected sqlite3_value objects may only be used with 3077** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3078** The [sqlite3_value_blob | sqlite3_value_type()] family of 3079** interfaces require protected sqlite3_value objects. 3080*/ 3081typedef struct Mem sqlite3_value; 3082 3083/* 3084** CAPI3REF: SQL Function Context Object 3085** 3086** The context in which an SQL function executes is stored in an 3087** sqlite3_context object. ^A pointer to an sqlite3_context object 3088** is always first parameter to [application-defined SQL functions]. 3089** The application-defined SQL function implementation will pass this 3090** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3091** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3092** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3093** and/or [sqlite3_set_auxdata()]. 3094*/ 3095typedef struct sqlite3_context sqlite3_context; 3096 3097/* 3098** CAPI3REF: Binding Values To Prepared Statements 3099** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3100** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3101** 3102** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3103** literals may be replaced by a [parameter] that matches one of following 3104** templates: 3105** 3106** <ul> 3107** <li> ? 3108** <li> ?NNN 3109** <li> :VVV 3110** <li> @VVV 3111** <li> $VVV 3112** </ul> 3113** 3114** In the templates above, NNN represents an integer literal, 3115** and VVV represents an alphanumeric identifier.)^ ^The values of these 3116** parameters (also called "host parameter names" or "SQL parameters") 3117** can be set using the sqlite3_bind_*() routines defined here. 3118** 3119** ^The first argument to the sqlite3_bind_*() routines is always 3120** a pointer to the [sqlite3_stmt] object returned from 3121** [sqlite3_prepare_v2()] or its variants. 3122** 3123** ^The second argument is the index of the SQL parameter to be set. 3124** ^The leftmost SQL parameter has an index of 1. ^When the same named 3125** SQL parameter is used more than once, second and subsequent 3126** occurrences have the same index as the first occurrence. 3127** ^The index for named parameters can be looked up using the 3128** [sqlite3_bind_parameter_index()] API if desired. ^The index 3129** for "?NNN" parameters is the value of NNN. 3130** ^The NNN value must be between 1 and the [sqlite3_limit()] 3131** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3132** 3133** ^The third argument is the value to bind to the parameter. 3134** 3135** ^(In those routines that have a fourth argument, its value is the 3136** number of bytes in the parameter. To be clear: the value is the 3137** number of <u>bytes</u> in the value, not the number of characters.)^ 3138** ^If the fourth parameter is negative, the length of the string is 3139** the number of bytes up to the first zero terminator. 3140** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3141** or sqlite3_bind_text16() then that parameter must be the byte offset 3142** where the NUL terminator would occur assuming the string were NUL 3143** terminated. If any NUL characters occur at byte offsets less than 3144** the value of the fourth parameter then the resulting string value will 3145** contain embedded NULs. The result of expressions involving strings 3146** with embedded NULs is undefined. 3147** 3148** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 3149** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 3150** string after SQLite has finished with it. ^The destructor is called 3151** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(), 3152** sqlite3_bind_text(), or sqlite3_bind_text16() fails. 3153** ^If the fifth argument is 3154** the special value [SQLITE_STATIC], then SQLite assumes that the 3155** information is in static, unmanaged space and does not need to be freed. 3156** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3157** SQLite makes its own private copy of the data immediately, before 3158** the sqlite3_bind_*() routine returns. 3159** 3160** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3161** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3162** (just an integer to hold its size) while it is being processed. 3163** Zeroblobs are intended to serve as placeholders for BLOBs whose 3164** content is later written using 3165** [sqlite3_blob_open | incremental BLOB I/O] routines. 3166** ^A negative value for the zeroblob results in a zero-length BLOB. 3167** 3168** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3169** for the [prepared statement] or with a prepared statement for which 3170** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3171** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3172** routine is passed a [prepared statement] that has been finalized, the 3173** result is undefined and probably harmful. 3174** 3175** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3176** ^Unbound parameters are interpreted as NULL. 3177** 3178** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3179** [error code] if anything goes wrong. 3180** ^[SQLITE_RANGE] is returned if the parameter 3181** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3182** 3183** See also: [sqlite3_bind_parameter_count()], 3184** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3185*/ 3186int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3187int sqlite3_bind_double(sqlite3_stmt*, int, double); 3188int sqlite3_bind_int(sqlite3_stmt*, int, int); 3189int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3190int sqlite3_bind_null(sqlite3_stmt*, int); 3191int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 3192int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3193int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3194int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3195 3196/* 3197** CAPI3REF: Number Of SQL Parameters 3198** 3199** ^This routine can be used to find the number of [SQL parameters] 3200** in a [prepared statement]. SQL parameters are tokens of the 3201** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3202** placeholders for values that are [sqlite3_bind_blob | bound] 3203** to the parameters at a later time. 3204** 3205** ^(This routine actually returns the index of the largest (rightmost) 3206** parameter. For all forms except ?NNN, this will correspond to the 3207** number of unique parameters. If parameters of the ?NNN form are used, 3208** there may be gaps in the list.)^ 3209** 3210** See also: [sqlite3_bind_blob|sqlite3_bind()], 3211** [sqlite3_bind_parameter_name()], and 3212** [sqlite3_bind_parameter_index()]. 3213*/ 3214int sqlite3_bind_parameter_count(sqlite3_stmt*); 3215 3216/* 3217** CAPI3REF: Name Of A Host Parameter 3218** 3219** ^The sqlite3_bind_parameter_name(P,N) interface returns 3220** the name of the N-th [SQL parameter] in the [prepared statement] P. 3221** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3222** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3223** respectively. 3224** In other words, the initial ":" or "$" or "@" or "?" 3225** is included as part of the name.)^ 3226** ^Parameters of the form "?" without a following integer have no name 3227** and are referred to as "nameless" or "anonymous parameters". 3228** 3229** ^The first host parameter has an index of 1, not 0. 3230** 3231** ^If the value N is out of range or if the N-th parameter is 3232** nameless, then NULL is returned. ^The returned string is 3233** always in UTF-8 encoding even if the named parameter was 3234** originally specified as UTF-16 in [sqlite3_prepare16()] or 3235** [sqlite3_prepare16_v2()]. 3236** 3237** See also: [sqlite3_bind_blob|sqlite3_bind()], 3238** [sqlite3_bind_parameter_count()], and 3239** [sqlite3_bind_parameter_index()]. 3240*/ 3241const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3242 3243/* 3244** CAPI3REF: Index Of A Parameter With A Given Name 3245** 3246** ^Return the index of an SQL parameter given its name. ^The 3247** index value returned is suitable for use as the second 3248** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3249** is returned if no matching parameter is found. ^The parameter 3250** name must be given in UTF-8 even if the original statement 3251** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3252** 3253** See also: [sqlite3_bind_blob|sqlite3_bind()], 3254** [sqlite3_bind_parameter_count()], and 3255** [sqlite3_bind_parameter_index()]. 3256*/ 3257int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3258 3259/* 3260** CAPI3REF: Reset All Bindings On A Prepared Statement 3261** 3262** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3263** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3264** ^Use this routine to reset all host parameters to NULL. 3265*/ 3266int sqlite3_clear_bindings(sqlite3_stmt*); 3267 3268/* 3269** CAPI3REF: Number Of Columns In A Result Set 3270** 3271** ^Return the number of columns in the result set returned by the 3272** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3273** statement that does not return data (for example an [UPDATE]). 3274** 3275** See also: [sqlite3_data_count()] 3276*/ 3277int sqlite3_column_count(sqlite3_stmt *pStmt); 3278 3279/* 3280** CAPI3REF: Column Names In A Result Set 3281** 3282** ^These routines return the name assigned to a particular column 3283** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3284** interface returns a pointer to a zero-terminated UTF-8 string 3285** and sqlite3_column_name16() returns a pointer to a zero-terminated 3286** UTF-16 string. ^The first parameter is the [prepared statement] 3287** that implements the [SELECT] statement. ^The second parameter is the 3288** column number. ^The leftmost column is number 0. 3289** 3290** ^The returned string pointer is valid until either the [prepared statement] 3291** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3292** reprepared by the first call to [sqlite3_step()] for a particular run 3293** or until the next call to 3294** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3295** 3296** ^If sqlite3_malloc() fails during the processing of either routine 3297** (for example during a conversion from UTF-8 to UTF-16) then a 3298** NULL pointer is returned. 3299** 3300** ^The name of a result column is the value of the "AS" clause for 3301** that column, if there is an AS clause. If there is no AS clause 3302** then the name of the column is unspecified and may change from 3303** one release of SQLite to the next. 3304*/ 3305const char *sqlite3_column_name(sqlite3_stmt*, int N); 3306const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3307 3308/* 3309** CAPI3REF: Source Of Data In A Query Result 3310** 3311** ^These routines provide a means to determine the database, table, and 3312** table column that is the origin of a particular result column in 3313** [SELECT] statement. 3314** ^The name of the database or table or column can be returned as 3315** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3316** the database name, the _table_ routines return the table name, and 3317** the origin_ routines return the column name. 3318** ^The returned string is valid until the [prepared statement] is destroyed 3319** using [sqlite3_finalize()] or until the statement is automatically 3320** reprepared by the first call to [sqlite3_step()] for a particular run 3321** or until the same information is requested 3322** again in a different encoding. 3323** 3324** ^The names returned are the original un-aliased names of the 3325** database, table, and column. 3326** 3327** ^The first argument to these interfaces is a [prepared statement]. 3328** ^These functions return information about the Nth result column returned by 3329** the statement, where N is the second function argument. 3330** ^The left-most column is column 0 for these routines. 3331** 3332** ^If the Nth column returned by the statement is an expression or 3333** subquery and is not a column value, then all of these functions return 3334** NULL. ^These routine might also return NULL if a memory allocation error 3335** occurs. ^Otherwise, they return the name of the attached database, table, 3336** or column that query result column was extracted from. 3337** 3338** ^As with all other SQLite APIs, those whose names end with "16" return 3339** UTF-16 encoded strings and the other functions return UTF-8. 3340** 3341** ^These APIs are only available if the library was compiled with the 3342** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3343** 3344** If two or more threads call one or more of these routines against the same 3345** prepared statement and column at the same time then the results are 3346** undefined. 3347** 3348** If two or more threads call one or more 3349** [sqlite3_column_database_name | column metadata interfaces] 3350** for the same [prepared statement] and result column 3351** at the same time then the results are undefined. 3352*/ 3353const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3354const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3355const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3356const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3357const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3358const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3359 3360/* 3361** CAPI3REF: Declared Datatype Of A Query Result 3362** 3363** ^(The first parameter is a [prepared statement]. 3364** If this statement is a [SELECT] statement and the Nth column of the 3365** returned result set of that [SELECT] is a table column (not an 3366** expression or subquery) then the declared type of the table 3367** column is returned.)^ ^If the Nth column of the result set is an 3368** expression or subquery, then a NULL pointer is returned. 3369** ^The returned string is always UTF-8 encoded. 3370** 3371** ^(For example, given the database schema: 3372** 3373** CREATE TABLE t1(c1 VARIANT); 3374** 3375** and the following statement to be compiled: 3376** 3377** SELECT c1 + 1, c1 FROM t1; 3378** 3379** this routine would return the string "VARIANT" for the second result 3380** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3381** 3382** ^SQLite uses dynamic run-time typing. ^So just because a column 3383** is declared to contain a particular type does not mean that the 3384** data stored in that column is of the declared type. SQLite is 3385** strongly typed, but the typing is dynamic not static. ^Type 3386** is associated with individual values, not with the containers 3387** used to hold those values. 3388*/ 3389const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3390const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3391 3392/* 3393** CAPI3REF: Evaluate An SQL Statement 3394** 3395** After a [prepared statement] has been prepared using either 3396** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3397** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3398** must be called one or more times to evaluate the statement. 3399** 3400** The details of the behavior of the sqlite3_step() interface depend 3401** on whether the statement was prepared using the newer "v2" interface 3402** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3403** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3404** new "v2" interface is recommended for new applications but the legacy 3405** interface will continue to be supported. 3406** 3407** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3408** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3409** ^With the "v2" interface, any of the other [result codes] or 3410** [extended result codes] might be returned as well. 3411** 3412** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3413** database locks it needs to do its job. ^If the statement is a [COMMIT] 3414** or occurs outside of an explicit transaction, then you can retry the 3415** statement. If the statement is not a [COMMIT] and occurs within an 3416** explicit transaction then you should rollback the transaction before 3417** continuing. 3418** 3419** ^[SQLITE_DONE] means that the statement has finished executing 3420** successfully. sqlite3_step() should not be called again on this virtual 3421** machine without first calling [sqlite3_reset()] to reset the virtual 3422** machine back to its initial state. 3423** 3424** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3425** is returned each time a new row of data is ready for processing by the 3426** caller. The values may be accessed using the [column access functions]. 3427** sqlite3_step() is called again to retrieve the next row of data. 3428** 3429** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3430** violation) has occurred. sqlite3_step() should not be called again on 3431** the VM. More information may be found by calling [sqlite3_errmsg()]. 3432** ^With the legacy interface, a more specific error code (for example, 3433** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3434** can be obtained by calling [sqlite3_reset()] on the 3435** [prepared statement]. ^In the "v2" interface, 3436** the more specific error code is returned directly by sqlite3_step(). 3437** 3438** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3439** Perhaps it was called on a [prepared statement] that has 3440** already been [sqlite3_finalize | finalized] or on one that had 3441** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3442** be the case that the same database connection is being used by two or 3443** more threads at the same moment in time. 3444** 3445** For all versions of SQLite up to and including 3.6.23.1, a call to 3446** [sqlite3_reset()] was required after sqlite3_step() returned anything 3447** other than [SQLITE_ROW] before any subsequent invocation of 3448** sqlite3_step(). Failure to reset the prepared statement using 3449** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3450** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3451** calling [sqlite3_reset()] automatically in this circumstance rather 3452** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3453** break because any application that ever receives an SQLITE_MISUSE error 3454** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3455** can be used to restore the legacy behavior. 3456** 3457** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3458** API always returns a generic error code, [SQLITE_ERROR], following any 3459** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3460** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3461** specific [error codes] that better describes the error. 3462** We admit that this is a goofy design. The problem has been fixed 3463** with the "v2" interface. If you prepare all of your SQL statements 3464** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3465** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3466** then the more specific [error codes] are returned directly 3467** by sqlite3_step(). The use of the "v2" interface is recommended. 3468*/ 3469int sqlite3_step(sqlite3_stmt*); 3470 3471/* 3472** CAPI3REF: Number of columns in a result set 3473** 3474** ^The sqlite3_data_count(P) interface returns the number of columns in the 3475** current row of the result set of [prepared statement] P. 3476** ^If prepared statement P does not have results ready to return 3477** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3478** interfaces) then sqlite3_data_count(P) returns 0. 3479** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3480** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 3481** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 3482** will return non-zero if previous call to [sqlite3_step](P) returned 3483** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 3484** where it always returns zero since each step of that multi-step 3485** pragma returns 0 columns of data. 3486** 3487** See also: [sqlite3_column_count()] 3488*/ 3489int sqlite3_data_count(sqlite3_stmt *pStmt); 3490 3491/* 3492** CAPI3REF: Fundamental Datatypes 3493** KEYWORDS: SQLITE_TEXT 3494** 3495** ^(Every value in SQLite has one of five fundamental datatypes: 3496** 3497** <ul> 3498** <li> 64-bit signed integer 3499** <li> 64-bit IEEE floating point number 3500** <li> string 3501** <li> BLOB 3502** <li> NULL 3503** </ul>)^ 3504** 3505** These constants are codes for each of those types. 3506** 3507** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3508** for a completely different meaning. Software that links against both 3509** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3510** SQLITE_TEXT. 3511*/ 3512#define SQLITE_INTEGER 1 3513#define SQLITE_FLOAT 2 3514#define SQLITE_BLOB 4 3515#define SQLITE_NULL 5 3516#ifdef SQLITE_TEXT 3517# undef SQLITE_TEXT 3518#else 3519# define SQLITE_TEXT 3 3520#endif 3521#define SQLITE3_TEXT 3 3522 3523/* 3524** CAPI3REF: Result Values From A Query 3525** KEYWORDS: {column access functions} 3526** 3527** These routines form the "result set" interface. 3528** 3529** ^These routines return information about a single column of the current 3530** result row of a query. ^In every case the first argument is a pointer 3531** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3532** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3533** and the second argument is the index of the column for which information 3534** should be returned. ^The leftmost column of the result set has the index 0. 3535** ^The number of columns in the result can be determined using 3536** [sqlite3_column_count()]. 3537** 3538** If the SQL statement does not currently point to a valid row, or if the 3539** column index is out of range, the result is undefined. 3540** These routines may only be called when the most recent call to 3541** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3542** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3543** If any of these routines are called after [sqlite3_reset()] or 3544** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3545** something other than [SQLITE_ROW], the results are undefined. 3546** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3547** are called from a different thread while any of these routines 3548** are pending, then the results are undefined. 3549** 3550** ^The sqlite3_column_type() routine returns the 3551** [SQLITE_INTEGER | datatype code] for the initial data type 3552** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3553** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3554** returned by sqlite3_column_type() is only meaningful if no type 3555** conversions have occurred as described below. After a type conversion, 3556** the value returned by sqlite3_column_type() is undefined. Future 3557** versions of SQLite may change the behavior of sqlite3_column_type() 3558** following a type conversion. 3559** 3560** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3561** routine returns the number of bytes in that BLOB or string. 3562** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3563** the string to UTF-8 and then returns the number of bytes. 3564** ^If the result is a numeric value then sqlite3_column_bytes() uses 3565** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3566** the number of bytes in that string. 3567** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3568** 3569** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3570** routine returns the number of bytes in that BLOB or string. 3571** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3572** the string to UTF-16 and then returns the number of bytes. 3573** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3574** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3575** the number of bytes in that string. 3576** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3577** 3578** ^The values returned by [sqlite3_column_bytes()] and 3579** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3580** of the string. ^For clarity: the values returned by 3581** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3582** bytes in the string, not the number of characters. 3583** 3584** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3585** even empty strings, are always zero-terminated. ^The return 3586** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3587** 3588** ^The object returned by [sqlite3_column_value()] is an 3589** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3590** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3591** If the [unprotected sqlite3_value] object returned by 3592** [sqlite3_column_value()] is used in any other way, including calls 3593** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3594** or [sqlite3_value_bytes()], then the behavior is undefined. 3595** 3596** These routines attempt to convert the value where appropriate. ^For 3597** example, if the internal representation is FLOAT and a text result 3598** is requested, [sqlite3_snprintf()] is used internally to perform the 3599** conversion automatically. ^(The following table details the conversions 3600** that are applied: 3601** 3602** <blockquote> 3603** <table border="1"> 3604** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3605** 3606** <tr><td> NULL <td> INTEGER <td> Result is 0 3607** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3608** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3609** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3610** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3611** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3612** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3613** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3614** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3615** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3616** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3617** <tr><td> TEXT <td> FLOAT <td> Use atof() 3618** <tr><td> TEXT <td> BLOB <td> No change 3619** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3620** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3621** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3622** </table> 3623** </blockquote>)^ 3624** 3625** The table above makes reference to standard C library functions atoi() 3626** and atof(). SQLite does not really use these functions. It has its 3627** own equivalent internal routines. The atoi() and atof() names are 3628** used in the table for brevity and because they are familiar to most 3629** C programmers. 3630** 3631** Note that when type conversions occur, pointers returned by prior 3632** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3633** sqlite3_column_text16() may be invalidated. 3634** Type conversions and pointer invalidations might occur 3635** in the following cases: 3636** 3637** <ul> 3638** <li> The initial content is a BLOB and sqlite3_column_text() or 3639** sqlite3_column_text16() is called. A zero-terminator might 3640** need to be added to the string.</li> 3641** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3642** sqlite3_column_text16() is called. The content must be converted 3643** to UTF-16.</li> 3644** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3645** sqlite3_column_text() is called. The content must be converted 3646** to UTF-8.</li> 3647** </ul> 3648** 3649** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3650** not invalidate a prior pointer, though of course the content of the buffer 3651** that the prior pointer references will have been modified. Other kinds 3652** of conversion are done in place when it is possible, but sometimes they 3653** are not possible and in those cases prior pointers are invalidated. 3654** 3655** The safest and easiest to remember policy is to invoke these routines 3656** in one of the following ways: 3657** 3658** <ul> 3659** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3660** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3661** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3662** </ul> 3663** 3664** In other words, you should call sqlite3_column_text(), 3665** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3666** into the desired format, then invoke sqlite3_column_bytes() or 3667** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3668** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3669** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3670** with calls to sqlite3_column_bytes(). 3671** 3672** ^The pointers returned are valid until a type conversion occurs as 3673** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3674** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3675** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3676** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3677** [sqlite3_free()]. 3678** 3679** ^(If a memory allocation error occurs during the evaluation of any 3680** of these routines, a default value is returned. The default value 3681** is either the integer 0, the floating point number 0.0, or a NULL 3682** pointer. Subsequent calls to [sqlite3_errcode()] will return 3683** [SQLITE_NOMEM].)^ 3684*/ 3685const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3686int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3687int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3688double sqlite3_column_double(sqlite3_stmt*, int iCol); 3689int sqlite3_column_int(sqlite3_stmt*, int iCol); 3690sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3691const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3692const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3693int sqlite3_column_type(sqlite3_stmt*, int iCol); 3694sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3695 3696/* 3697** CAPI3REF: Destroy A Prepared Statement Object 3698** 3699** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3700** ^If the most recent evaluation of the statement encountered no errors 3701** or if the statement is never been evaluated, then sqlite3_finalize() returns 3702** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 3703** sqlite3_finalize(S) returns the appropriate [error code] or 3704** [extended error code]. 3705** 3706** ^The sqlite3_finalize(S) routine can be called at any point during 3707** the life cycle of [prepared statement] S: 3708** before statement S is ever evaluated, after 3709** one or more calls to [sqlite3_reset()], or after any call 3710** to [sqlite3_step()] regardless of whether or not the statement has 3711** completed execution. 3712** 3713** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 3714** 3715** The application must finalize every [prepared statement] in order to avoid 3716** resource leaks. It is a grievous error for the application to try to use 3717** a prepared statement after it has been finalized. Any use of a prepared 3718** statement after it has been finalized can result in undefined and 3719** undesirable behavior such as segfaults and heap corruption. 3720*/ 3721int sqlite3_finalize(sqlite3_stmt *pStmt); 3722 3723/* 3724** CAPI3REF: Reset A Prepared Statement Object 3725** 3726** The sqlite3_reset() function is called to reset a [prepared statement] 3727** object back to its initial state, ready to be re-executed. 3728** ^Any SQL statement variables that had values bound to them using 3729** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3730** Use [sqlite3_clear_bindings()] to reset the bindings. 3731** 3732** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3733** back to the beginning of its program. 3734** 3735** ^If the most recent call to [sqlite3_step(S)] for the 3736** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3737** or if [sqlite3_step(S)] has never before been called on S, 3738** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3739** 3740** ^If the most recent call to [sqlite3_step(S)] for the 3741** [prepared statement] S indicated an error, then 3742** [sqlite3_reset(S)] returns an appropriate [error code]. 3743** 3744** ^The [sqlite3_reset(S)] interface does not change the values 3745** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3746*/ 3747int sqlite3_reset(sqlite3_stmt *pStmt); 3748 3749/* 3750** CAPI3REF: Create Or Redefine SQL Functions 3751** KEYWORDS: {function creation routines} 3752** KEYWORDS: {application-defined SQL function} 3753** KEYWORDS: {application-defined SQL functions} 3754** 3755** ^These functions (collectively known as "function creation routines") 3756** are used to add SQL functions or aggregates or to redefine the behavior 3757** of existing SQL functions or aggregates. The only differences between 3758** these routines are the text encoding expected for 3759** the second parameter (the name of the function being created) 3760** and the presence or absence of a destructor callback for 3761** the application data pointer. 3762** 3763** ^The first parameter is the [database connection] to which the SQL 3764** function is to be added. ^If an application uses more than one database 3765** connection then application-defined SQL functions must be added 3766** to each database connection separately. 3767** 3768** ^The second parameter is the name of the SQL function to be created or 3769** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 3770** representation, exclusive of the zero-terminator. ^Note that the name 3771** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 3772** ^Any attempt to create a function with a longer name 3773** will result in [SQLITE_MISUSE] being returned. 3774** 3775** ^The third parameter (nArg) 3776** is the number of arguments that the SQL function or 3777** aggregate takes. ^If this parameter is -1, then the SQL function or 3778** aggregate may take any number of arguments between 0 and the limit 3779** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3780** parameter is less than -1 or greater than 127 then the behavior is 3781** undefined. 3782** 3783** ^The fourth parameter, eTextRep, specifies what 3784** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3785** its parameters. Every SQL function implementation must be able to work 3786** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3787** more efficient with one encoding than another. ^An application may 3788** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3789** times with the same function but with different values of eTextRep. 3790** ^When multiple implementations of the same function are available, SQLite 3791** will pick the one that involves the least amount of data conversion. 3792** If there is only a single implementation which does not care what text 3793** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3794** 3795** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3796** function can gain access to this pointer using [sqlite3_user_data()].)^ 3797** 3798** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 3799** pointers to C-language functions that implement the SQL function or 3800** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3801** callback only; NULL pointers must be passed as the xStep and xFinal 3802** parameters. ^An aggregate SQL function requires an implementation of xStep 3803** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 3804** SQL function or aggregate, pass NULL pointers for all three function 3805** callbacks. 3806** 3807** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 3808** then it is destructor for the application data pointer. 3809** The destructor is invoked when the function is deleted, either by being 3810** overloaded or when the database connection closes.)^ 3811** ^The destructor is also invoked if the call to 3812** sqlite3_create_function_v2() fails. 3813** ^When the destructor callback of the tenth parameter is invoked, it 3814** is passed a single argument which is a copy of the application data 3815** pointer which was the fifth parameter to sqlite3_create_function_v2(). 3816** 3817** ^It is permitted to register multiple implementations of the same 3818** functions with the same name but with either differing numbers of 3819** arguments or differing preferred text encodings. ^SQLite will use 3820** the implementation that most closely matches the way in which the 3821** SQL function is used. ^A function implementation with a non-negative 3822** nArg parameter is a better match than a function implementation with 3823** a negative nArg. ^A function where the preferred text encoding 3824** matches the database encoding is a better 3825** match than a function where the encoding is different. 3826** ^A function where the encoding difference is between UTF16le and UTF16be 3827** is a closer match than a function where the encoding difference is 3828** between UTF8 and UTF16. 3829** 3830** ^Built-in functions may be overloaded by new application-defined functions. 3831** 3832** ^An application-defined function is permitted to call other 3833** SQLite interfaces. However, such calls must not 3834** close the database connection nor finalize or reset the prepared 3835** statement in which the function is running. 3836*/ 3837int sqlite3_create_function( 3838 sqlite3 *db, 3839 const char *zFunctionName, 3840 int nArg, 3841 int eTextRep, 3842 void *pApp, 3843 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3844 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3845 void (*xFinal)(sqlite3_context*) 3846); 3847int sqlite3_create_function16( 3848 sqlite3 *db, 3849 const void *zFunctionName, 3850 int nArg, 3851 int eTextRep, 3852 void *pApp, 3853 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3854 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3855 void (*xFinal)(sqlite3_context*) 3856); 3857int sqlite3_create_function_v2( 3858 sqlite3 *db, 3859 const char *zFunctionName, 3860 int nArg, 3861 int eTextRep, 3862 void *pApp, 3863 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3864 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3865 void (*xFinal)(sqlite3_context*), 3866 void(*xDestroy)(void*) 3867); 3868 3869/* 3870** CAPI3REF: Text Encodings 3871** 3872** These constant define integer codes that represent the various 3873** text encodings supported by SQLite. 3874*/ 3875#define SQLITE_UTF8 1 3876#define SQLITE_UTF16LE 2 3877#define SQLITE_UTF16BE 3 3878#define SQLITE_UTF16 4 /* Use native byte order */ 3879#define SQLITE_ANY 5 /* sqlite3_create_function only */ 3880#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3881 3882/* 3883** CAPI3REF: Deprecated Functions 3884** DEPRECATED 3885** 3886** These functions are [deprecated]. In order to maintain 3887** backwards compatibility with older code, these functions continue 3888** to be supported. However, new applications should avoid 3889** the use of these functions. To help encourage people to avoid 3890** using these functions, we are not going to tell you what they do. 3891*/ 3892#ifndef SQLITE_OMIT_DEPRECATED 3893SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3894SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3895SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3896SQLITE_DEPRECATED int sqlite3_global_recover(void); 3897SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3898SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3899#endif 3900 3901/* 3902** CAPI3REF: Obtaining SQL Function Parameter Values 3903** 3904** The C-language implementation of SQL functions and aggregates uses 3905** this set of interface routines to access the parameter values on 3906** the function or aggregate. 3907** 3908** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3909** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3910** define callbacks that implement the SQL functions and aggregates. 3911** The 3rd parameter to these callbacks is an array of pointers to 3912** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3913** each parameter to the SQL function. These routines are used to 3914** extract values from the [sqlite3_value] objects. 3915** 3916** These routines work only with [protected sqlite3_value] objects. 3917** Any attempt to use these routines on an [unprotected sqlite3_value] 3918** object results in undefined behavior. 3919** 3920** ^These routines work just like the corresponding [column access functions] 3921** except that these routines take a single [protected sqlite3_value] object 3922** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3923** 3924** ^The sqlite3_value_text16() interface extracts a UTF-16 string 3925** in the native byte-order of the host machine. ^The 3926** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3927** extract UTF-16 strings as big-endian and little-endian respectively. 3928** 3929** ^(The sqlite3_value_numeric_type() interface attempts to apply 3930** numeric affinity to the value. This means that an attempt is 3931** made to convert the value to an integer or floating point. If 3932** such a conversion is possible without loss of information (in other 3933** words, if the value is a string that looks like a number) 3934** then the conversion is performed. Otherwise no conversion occurs. 3935** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 3936** 3937** Please pay particular attention to the fact that the pointer returned 3938** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3939** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3940** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3941** or [sqlite3_value_text16()]. 3942** 3943** These routines must be called from the same thread as 3944** the SQL function that supplied the [sqlite3_value*] parameters. 3945*/ 3946const void *sqlite3_value_blob(sqlite3_value*); 3947int sqlite3_value_bytes(sqlite3_value*); 3948int sqlite3_value_bytes16(sqlite3_value*); 3949double sqlite3_value_double(sqlite3_value*); 3950int sqlite3_value_int(sqlite3_value*); 3951sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3952const unsigned char *sqlite3_value_text(sqlite3_value*); 3953const void *sqlite3_value_text16(sqlite3_value*); 3954const void *sqlite3_value_text16le(sqlite3_value*); 3955const void *sqlite3_value_text16be(sqlite3_value*); 3956int sqlite3_value_type(sqlite3_value*); 3957int sqlite3_value_numeric_type(sqlite3_value*); 3958 3959/* 3960** CAPI3REF: Obtain Aggregate Function Context 3961** 3962** Implementations of aggregate SQL functions use this 3963** routine to allocate memory for storing their state. 3964** 3965** ^The first time the sqlite3_aggregate_context(C,N) routine is called 3966** for a particular aggregate function, SQLite 3967** allocates N of memory, zeroes out that memory, and returns a pointer 3968** to the new memory. ^On second and subsequent calls to 3969** sqlite3_aggregate_context() for the same aggregate function instance, 3970** the same buffer is returned. Sqlite3_aggregate_context() is normally 3971** called once for each invocation of the xStep callback and then one 3972** last time when the xFinal callback is invoked. ^(When no rows match 3973** an aggregate query, the xStep() callback of the aggregate function 3974** implementation is never called and xFinal() is called exactly once. 3975** In those cases, sqlite3_aggregate_context() might be called for the 3976** first time from within xFinal().)^ 3977** 3978** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is 3979** less than or equal to zero or if a memory allocate error occurs. 3980** 3981** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 3982** determined by the N parameter on first successful call. Changing the 3983** value of N in subsequent call to sqlite3_aggregate_context() within 3984** the same aggregate function instance will not resize the memory 3985** allocation.)^ 3986** 3987** ^SQLite automatically frees the memory allocated by 3988** sqlite3_aggregate_context() when the aggregate query concludes. 3989** 3990** The first parameter must be a copy of the 3991** [sqlite3_context | SQL function context] that is the first parameter 3992** to the xStep or xFinal callback routine that implements the aggregate 3993** function. 3994** 3995** This routine must be called from the same thread in which 3996** the aggregate SQL function is running. 3997*/ 3998void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 3999 4000/* 4001** CAPI3REF: User Data For Functions 4002** 4003** ^The sqlite3_user_data() interface returns a copy of 4004** the pointer that was the pUserData parameter (the 5th parameter) 4005** of the [sqlite3_create_function()] 4006** and [sqlite3_create_function16()] routines that originally 4007** registered the application defined function. 4008** 4009** This routine must be called from the same thread in which 4010** the application-defined function is running. 4011*/ 4012void *sqlite3_user_data(sqlite3_context*); 4013 4014/* 4015** CAPI3REF: Database Connection For Functions 4016** 4017** ^The sqlite3_context_db_handle() interface returns a copy of 4018** the pointer to the [database connection] (the 1st parameter) 4019** of the [sqlite3_create_function()] 4020** and [sqlite3_create_function16()] routines that originally 4021** registered the application defined function. 4022*/ 4023sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4024 4025/* 4026** CAPI3REF: Function Auxiliary Data 4027** 4028** The following two functions may be used by scalar SQL functions to 4029** associate metadata with argument values. If the same value is passed to 4030** multiple invocations of the same SQL function during query execution, under 4031** some circumstances the associated metadata may be preserved. This may 4032** be used, for example, to add a regular-expression matching scalar 4033** function. The compiled version of the regular expression is stored as 4034** metadata associated with the SQL value passed as the regular expression 4035** pattern. The compiled regular expression can be reused on multiple 4036** invocations of the same function so that the original pattern string 4037** does not need to be recompiled on each invocation. 4038** 4039** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4040** associated by the sqlite3_set_auxdata() function with the Nth argument 4041** value to the application-defined function. ^If no metadata has been ever 4042** been set for the Nth argument of the function, or if the corresponding 4043** function parameter has changed since the meta-data was set, 4044** then sqlite3_get_auxdata() returns a NULL pointer. 4045** 4046** ^The sqlite3_set_auxdata() interface saves the metadata 4047** pointed to by its 3rd parameter as the metadata for the N-th 4048** argument of the application-defined function. Subsequent 4049** calls to sqlite3_get_auxdata() might return this data, if it has 4050** not been destroyed. 4051** ^If it is not NULL, SQLite will invoke the destructor 4052** function given by the 4th parameter to sqlite3_set_auxdata() on 4053** the metadata when the corresponding function parameter changes 4054** or when the SQL statement completes, whichever comes first. 4055** 4056** SQLite is free to call the destructor and drop metadata on any 4057** parameter of any function at any time. ^The only guarantee is that 4058** the destructor will be called before the metadata is dropped. 4059** 4060** ^(In practice, metadata is preserved between function calls for 4061** expressions that are constant at compile time. This includes literal 4062** values and [parameters].)^ 4063** 4064** These routines must be called from the same thread in which 4065** the SQL function is running. 4066*/ 4067void *sqlite3_get_auxdata(sqlite3_context*, int N); 4068void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4069 4070 4071/* 4072** CAPI3REF: Constants Defining Special Destructor Behavior 4073** 4074** These are special values for the destructor that is passed in as the 4075** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4076** argument is SQLITE_STATIC, it means that the content pointer is constant 4077** and will never change. It does not need to be destroyed. ^The 4078** SQLITE_TRANSIENT value means that the content will likely change in 4079** the near future and that SQLite should make its own private copy of 4080** the content before returning. 4081** 4082** The typedef is necessary to work around problems in certain 4083** C++ compilers. See ticket #2191. 4084*/ 4085typedef void (*sqlite3_destructor_type)(void*); 4086#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4087#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4088 4089/* 4090** CAPI3REF: Setting The Result Of An SQL Function 4091** 4092** These routines are used by the xFunc or xFinal callbacks that 4093** implement SQL functions and aggregates. See 4094** [sqlite3_create_function()] and [sqlite3_create_function16()] 4095** for additional information. 4096** 4097** These functions work very much like the [parameter binding] family of 4098** functions used to bind values to host parameters in prepared statements. 4099** Refer to the [SQL parameter] documentation for additional information. 4100** 4101** ^The sqlite3_result_blob() interface sets the result from 4102** an application-defined function to be the BLOB whose content is pointed 4103** to by the second parameter and which is N bytes long where N is the 4104** third parameter. 4105** 4106** ^The sqlite3_result_zeroblob() interfaces set the result of 4107** the application-defined function to be a BLOB containing all zero 4108** bytes and N bytes in size, where N is the value of the 2nd parameter. 4109** 4110** ^The sqlite3_result_double() interface sets the result from 4111** an application-defined function to be a floating point value specified 4112** by its 2nd argument. 4113** 4114** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4115** cause the implemented SQL function to throw an exception. 4116** ^SQLite uses the string pointed to by the 4117** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4118** as the text of an error message. ^SQLite interprets the error 4119** message string from sqlite3_result_error() as UTF-8. ^SQLite 4120** interprets the string from sqlite3_result_error16() as UTF-16 in native 4121** byte order. ^If the third parameter to sqlite3_result_error() 4122** or sqlite3_result_error16() is negative then SQLite takes as the error 4123** message all text up through the first zero character. 4124** ^If the third parameter to sqlite3_result_error() or 4125** sqlite3_result_error16() is non-negative then SQLite takes that many 4126** bytes (not characters) from the 2nd parameter as the error message. 4127** ^The sqlite3_result_error() and sqlite3_result_error16() 4128** routines make a private copy of the error message text before 4129** they return. Hence, the calling function can deallocate or 4130** modify the text after they return without harm. 4131** ^The sqlite3_result_error_code() function changes the error code 4132** returned by SQLite as a result of an error in a function. ^By default, 4133** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4134** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4135** 4136** ^The sqlite3_result_toobig() interface causes SQLite to throw an error 4137** indicating that a string or BLOB is too long to represent. 4138** 4139** ^The sqlite3_result_nomem() interface causes SQLite to throw an error 4140** indicating that a memory allocation failed. 4141** 4142** ^The sqlite3_result_int() interface sets the return value 4143** of the application-defined function to be the 32-bit signed integer 4144** value given in the 2nd argument. 4145** ^The sqlite3_result_int64() interface sets the return value 4146** of the application-defined function to be the 64-bit signed integer 4147** value given in the 2nd argument. 4148** 4149** ^The sqlite3_result_null() interface sets the return value 4150** of the application-defined function to be NULL. 4151** 4152** ^The sqlite3_result_text(), sqlite3_result_text16(), 4153** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4154** set the return value of the application-defined function to be 4155** a text string which is represented as UTF-8, UTF-16 native byte order, 4156** UTF-16 little endian, or UTF-16 big endian, respectively. 4157** ^SQLite takes the text result from the application from 4158** the 2nd parameter of the sqlite3_result_text* interfaces. 4159** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4160** is negative, then SQLite takes result text from the 2nd parameter 4161** through the first zero character. 4162** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4163** is non-negative, then as many bytes (not characters) of the text 4164** pointed to by the 2nd parameter are taken as the application-defined 4165** function result. If the 3rd parameter is non-negative, then it 4166** must be the byte offset into the string where the NUL terminator would 4167** appear if the string where NUL terminated. If any NUL characters occur 4168** in the string at a byte offset that is less than the value of the 3rd 4169** parameter, then the resulting string will contain embedded NULs and the 4170** result of expressions operating on strings with embedded NULs is undefined. 4171** ^If the 4th parameter to the sqlite3_result_text* interfaces 4172** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4173** function as the destructor on the text or BLOB result when it has 4174** finished using that result. 4175** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4176** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4177** assumes that the text or BLOB result is in constant space and does not 4178** copy the content of the parameter nor call a destructor on the content 4179** when it has finished using that result. 4180** ^If the 4th parameter to the sqlite3_result_text* interfaces 4181** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4182** then SQLite makes a copy of the result into space obtained from 4183** from [sqlite3_malloc()] before it returns. 4184** 4185** ^The sqlite3_result_value() interface sets the result of 4186** the application-defined function to be a copy the 4187** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4188** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4189** so that the [sqlite3_value] specified in the parameter may change or 4190** be deallocated after sqlite3_result_value() returns without harm. 4191** ^A [protected sqlite3_value] object may always be used where an 4192** [unprotected sqlite3_value] object is required, so either 4193** kind of [sqlite3_value] object can be used with this interface. 4194** 4195** If these routines are called from within the different thread 4196** than the one containing the application-defined function that received 4197** the [sqlite3_context] pointer, the results are undefined. 4198*/ 4199void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4200void sqlite3_result_double(sqlite3_context*, double); 4201void sqlite3_result_error(sqlite3_context*, const char*, int); 4202void sqlite3_result_error16(sqlite3_context*, const void*, int); 4203void sqlite3_result_error_toobig(sqlite3_context*); 4204void sqlite3_result_error_nomem(sqlite3_context*); 4205void sqlite3_result_error_code(sqlite3_context*, int); 4206void sqlite3_result_int(sqlite3_context*, int); 4207void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4208void sqlite3_result_null(sqlite3_context*); 4209void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4210void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4211void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4212void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4213void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4214void sqlite3_result_zeroblob(sqlite3_context*, int n); 4215 4216/* 4217** CAPI3REF: Define New Collating Sequences 4218** 4219** ^These functions add, remove, or modify a [collation] associated 4220** with the [database connection] specified as the first argument. 4221** 4222** ^The name of the collation is a UTF-8 string 4223** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4224** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4225** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4226** considered to be the same name. 4227** 4228** ^(The third argument (eTextRep) must be one of the constants: 4229** <ul> 4230** <li> [SQLITE_UTF8], 4231** <li> [SQLITE_UTF16LE], 4232** <li> [SQLITE_UTF16BE], 4233** <li> [SQLITE_UTF16], or 4234** <li> [SQLITE_UTF16_ALIGNED]. 4235** </ul>)^ 4236** ^The eTextRep argument determines the encoding of strings passed 4237** to the collating function callback, xCallback. 4238** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4239** force strings to be UTF16 with native byte order. 4240** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4241** on an even byte address. 4242** 4243** ^The fourth argument, pArg, is an application data pointer that is passed 4244** through as the first argument to the collating function callback. 4245** 4246** ^The fifth argument, xCallback, is a pointer to the collating function. 4247** ^Multiple collating functions can be registered using the same name but 4248** with different eTextRep parameters and SQLite will use whichever 4249** function requires the least amount of data transformation. 4250** ^If the xCallback argument is NULL then the collating function is 4251** deleted. ^When all collating functions having the same name are deleted, 4252** that collation is no longer usable. 4253** 4254** ^The collating function callback is invoked with a copy of the pArg 4255** application data pointer and with two strings in the encoding specified 4256** by the eTextRep argument. The collating function must return an 4257** integer that is negative, zero, or positive 4258** if the first string is less than, equal to, or greater than the second, 4259** respectively. A collating function must always return the same answer 4260** given the same inputs. If two or more collating functions are registered 4261** to the same collation name (using different eTextRep values) then all 4262** must give an equivalent answer when invoked with equivalent strings. 4263** The collating function must obey the following properties for all 4264** strings A, B, and C: 4265** 4266** <ol> 4267** <li> If A==B then B==A. 4268** <li> If A==B and B==C then A==C. 4269** <li> If A<B THEN B>A. 4270** <li> If A<B and B<C then A<C. 4271** </ol> 4272** 4273** If a collating function fails any of the above constraints and that 4274** collating function is registered and used, then the behavior of SQLite 4275** is undefined. 4276** 4277** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4278** with the addition that the xDestroy callback is invoked on pArg when 4279** the collating function is deleted. 4280** ^Collating functions are deleted when they are overridden by later 4281** calls to the collation creation functions or when the 4282** [database connection] is closed using [sqlite3_close()]. 4283** 4284** ^The xDestroy callback is <u>not</u> called if the 4285** sqlite3_create_collation_v2() function fails. Applications that invoke 4286** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4287** check the return code and dispose of the application data pointer 4288** themselves rather than expecting SQLite to deal with it for them. 4289** This is different from every other SQLite interface. The inconsistency 4290** is unfortunate but cannot be changed without breaking backwards 4291** compatibility. 4292** 4293** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4294*/ 4295int sqlite3_create_collation( 4296 sqlite3*, 4297 const char *zName, 4298 int eTextRep, 4299 void *pArg, 4300 int(*xCompare)(void*,int,const void*,int,const void*) 4301); 4302int sqlite3_create_collation_v2( 4303 sqlite3*, 4304 const char *zName, 4305 int eTextRep, 4306 void *pArg, 4307 int(*xCompare)(void*,int,const void*,int,const void*), 4308 void(*xDestroy)(void*) 4309); 4310int sqlite3_create_collation16( 4311 sqlite3*, 4312 const void *zName, 4313 int eTextRep, 4314 void *pArg, 4315 int(*xCompare)(void*,int,const void*,int,const void*) 4316); 4317 4318/* 4319** CAPI3REF: Collation Needed Callbacks 4320** 4321** ^To avoid having to register all collation sequences before a database 4322** can be used, a single callback function may be registered with the 4323** [database connection] to be invoked whenever an undefined collation 4324** sequence is required. 4325** 4326** ^If the function is registered using the sqlite3_collation_needed() API, 4327** then it is passed the names of undefined collation sequences as strings 4328** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4329** the names are passed as UTF-16 in machine native byte order. 4330** ^A call to either function replaces the existing collation-needed callback. 4331** 4332** ^(When the callback is invoked, the first argument passed is a copy 4333** of the second argument to sqlite3_collation_needed() or 4334** sqlite3_collation_needed16(). The second argument is the database 4335** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4336** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4337** sequence function required. The fourth parameter is the name of the 4338** required collation sequence.)^ 4339** 4340** The callback function should register the desired collation using 4341** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4342** [sqlite3_create_collation_v2()]. 4343*/ 4344int sqlite3_collation_needed( 4345 sqlite3*, 4346 void*, 4347 void(*)(void*,sqlite3*,int eTextRep,const char*) 4348); 4349int sqlite3_collation_needed16( 4350 sqlite3*, 4351 void*, 4352 void(*)(void*,sqlite3*,int eTextRep,const void*) 4353); 4354 4355#ifdef SQLITE_HAS_CODEC 4356/* 4357** Specify the key for an encrypted database. This routine should be 4358** called right after sqlite3_open(). 4359** 4360** The code to implement this API is not available in the public release 4361** of SQLite. 4362*/ 4363int sqlite3_key( 4364 sqlite3 *db, /* Database to be rekeyed */ 4365 const void *pKey, int nKey /* The key */ 4366); 4367 4368/* 4369** Change the key on an open database. If the current database is not 4370** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4371** database is decrypted. 4372** 4373** The code to implement this API is not available in the public release 4374** of SQLite. 4375*/ 4376int sqlite3_rekey( 4377 sqlite3 *db, /* Database to be rekeyed */ 4378 const void *pKey, int nKey /* The new key */ 4379); 4380 4381/* 4382** Specify the activation key for a SEE database. Unless 4383** activated, none of the SEE routines will work. 4384*/ 4385void sqlite3_activate_see( 4386 const char *zPassPhrase /* Activation phrase */ 4387); 4388#endif 4389 4390#ifdef SQLITE_ENABLE_CEROD 4391/* 4392** Specify the activation key for a CEROD database. Unless 4393** activated, none of the CEROD routines will work. 4394*/ 4395void sqlite3_activate_cerod( 4396 const char *zPassPhrase /* Activation phrase */ 4397); 4398#endif 4399 4400/* 4401** CAPI3REF: Suspend Execution For A Short Time 4402** 4403** The sqlite3_sleep() function causes the current thread to suspend execution 4404** for at least a number of milliseconds specified in its parameter. 4405** 4406** If the operating system does not support sleep requests with 4407** millisecond time resolution, then the time will be rounded up to 4408** the nearest second. The number of milliseconds of sleep actually 4409** requested from the operating system is returned. 4410** 4411** ^SQLite implements this interface by calling the xSleep() 4412** method of the default [sqlite3_vfs] object. If the xSleep() method 4413** of the default VFS is not implemented correctly, or not implemented at 4414** all, then the behavior of sqlite3_sleep() may deviate from the description 4415** in the previous paragraphs. 4416*/ 4417int sqlite3_sleep(int); 4418 4419/* 4420** CAPI3REF: Name Of The Folder Holding Temporary Files 4421** 4422** ^(If this global variable is made to point to a string which is 4423** the name of a folder (a.k.a. directory), then all temporary files 4424** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4425** will be placed in that directory.)^ ^If this variable 4426** is a NULL pointer, then SQLite performs a search for an appropriate 4427** temporary file directory. 4428** 4429** It is not safe to read or modify this variable in more than one 4430** thread at a time. It is not safe to read or modify this variable 4431** if a [database connection] is being used at the same time in a separate 4432** thread. 4433** It is intended that this variable be set once 4434** as part of process initialization and before any SQLite interface 4435** routines have been called and that this variable remain unchanged 4436** thereafter. 4437** 4438** ^The [temp_store_directory pragma] may modify this variable and cause 4439** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4440** the [temp_store_directory pragma] always assumes that any string 4441** that this variable points to is held in memory obtained from 4442** [sqlite3_malloc] and the pragma may attempt to free that memory 4443** using [sqlite3_free]. 4444** Hence, if this variable is modified directly, either it should be 4445** made NULL or made to point to memory obtained from [sqlite3_malloc] 4446** or else the use of the [temp_store_directory pragma] should be avoided. 4447*/ 4448SQLITE_EXTERN char *sqlite3_temp_directory; 4449 4450/* 4451** CAPI3REF: Test For Auto-Commit Mode 4452** KEYWORDS: {autocommit mode} 4453** 4454** ^The sqlite3_get_autocommit() interface returns non-zero or 4455** zero if the given database connection is or is not in autocommit mode, 4456** respectively. ^Autocommit mode is on by default. 4457** ^Autocommit mode is disabled by a [BEGIN] statement. 4458** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 4459** 4460** If certain kinds of errors occur on a statement within a multi-statement 4461** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 4462** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 4463** transaction might be rolled back automatically. The only way to 4464** find out whether SQLite automatically rolled back the transaction after 4465** an error is to use this function. 4466** 4467** If another thread changes the autocommit status of the database 4468** connection while this routine is running, then the return value 4469** is undefined. 4470*/ 4471int sqlite3_get_autocommit(sqlite3*); 4472 4473/* 4474** CAPI3REF: Find The Database Handle Of A Prepared Statement 4475** 4476** ^The sqlite3_db_handle interface returns the [database connection] handle 4477** to which a [prepared statement] belongs. ^The [database connection] 4478** returned by sqlite3_db_handle is the same [database connection] 4479** that was the first argument 4480** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 4481** create the statement in the first place. 4482*/ 4483sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 4484 4485/* 4486** CAPI3REF: Return The Filename For A Database Connection 4487** 4488** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 4489** associated with database N of connection D. ^The main database file 4490** has the name "main". If there is no attached database N on the database 4491** connection D, or if database N is a temporary or in-memory database, then 4492** a NULL pointer is returned. 4493** 4494** ^The filename returned by this function is the output of the 4495** xFullPathname method of the [VFS]. ^In other words, the filename 4496** will be an absolute pathname, even if the filename used 4497** to open the database originally was a URI or relative pathname. 4498*/ 4499const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 4500 4501/* 4502** CAPI3REF: Determine if a database is read-only 4503** 4504** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 4505** of connection D is read-only, 0 if it is read/write, or -1 if N is not 4506** the name of a database on connection D. 4507*/ 4508int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 4509 4510/* 4511** CAPI3REF: Find the next prepared statement 4512** 4513** ^This interface returns a pointer to the next [prepared statement] after 4514** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 4515** then this interface returns a pointer to the first prepared statement 4516** associated with the database connection pDb. ^If no prepared statement 4517** satisfies the conditions of this routine, it returns NULL. 4518** 4519** The [database connection] pointer D in a call to 4520** [sqlite3_next_stmt(D,S)] must refer to an open database 4521** connection and in particular must not be a NULL pointer. 4522*/ 4523sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 4524 4525/* 4526** CAPI3REF: Commit And Rollback Notification Callbacks 4527** 4528** ^The sqlite3_commit_hook() interface registers a callback 4529** function to be invoked whenever a transaction is [COMMIT | committed]. 4530** ^Any callback set by a previous call to sqlite3_commit_hook() 4531** for the same database connection is overridden. 4532** ^The sqlite3_rollback_hook() interface registers a callback 4533** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 4534** ^Any callback set by a previous call to sqlite3_rollback_hook() 4535** for the same database connection is overridden. 4536** ^The pArg argument is passed through to the callback. 4537** ^If the callback on a commit hook function returns non-zero, 4538** then the commit is converted into a rollback. 4539** 4540** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 4541** return the P argument from the previous call of the same function 4542** on the same [database connection] D, or NULL for 4543** the first call for each function on D. 4544** 4545** The commit and rollback hook callbacks are not reentrant. 4546** The callback implementation must not do anything that will modify 4547** the database connection that invoked the callback. Any actions 4548** to modify the database connection must be deferred until after the 4549** completion of the [sqlite3_step()] call that triggered the commit 4550** or rollback hook in the first place. 4551** Note that running any other SQL statements, including SELECT statements, 4552** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 4553** the database connections for the meaning of "modify" in this paragraph. 4554** 4555** ^Registering a NULL function disables the callback. 4556** 4557** ^When the commit hook callback routine returns zero, the [COMMIT] 4558** operation is allowed to continue normally. ^If the commit hook 4559** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 4560** ^The rollback hook is invoked on a rollback that results from a commit 4561** hook returning non-zero, just as it would be with any other rollback. 4562** 4563** ^For the purposes of this API, a transaction is said to have been 4564** rolled back if an explicit "ROLLBACK" statement is executed, or 4565** an error or constraint causes an implicit rollback to occur. 4566** ^The rollback callback is not invoked if a transaction is 4567** automatically rolled back because the database connection is closed. 4568** 4569** See also the [sqlite3_update_hook()] interface. 4570*/ 4571void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 4572void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 4573 4574/* 4575** CAPI3REF: Data Change Notification Callbacks 4576** 4577** ^The sqlite3_update_hook() interface registers a callback function 4578** with the [database connection] identified by the first argument 4579** to be invoked whenever a row is updated, inserted or deleted. 4580** ^Any callback set by a previous call to this function 4581** for the same database connection is overridden. 4582** 4583** ^The second argument is a pointer to the function to invoke when a 4584** row is updated, inserted or deleted. 4585** ^The first argument to the callback is a copy of the third argument 4586** to sqlite3_update_hook(). 4587** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 4588** or [SQLITE_UPDATE], depending on the operation that caused the callback 4589** to be invoked. 4590** ^The third and fourth arguments to the callback contain pointers to the 4591** database and table name containing the affected row. 4592** ^The final callback parameter is the [rowid] of the row. 4593** ^In the case of an update, this is the [rowid] after the update takes place. 4594** 4595** ^(The update hook is not invoked when internal system tables are 4596** modified (i.e. sqlite_master and sqlite_sequence).)^ 4597** 4598** ^In the current implementation, the update hook 4599** is not invoked when duplication rows are deleted because of an 4600** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 4601** invoked when rows are deleted using the [truncate optimization]. 4602** The exceptions defined in this paragraph might change in a future 4603** release of SQLite. 4604** 4605** The update hook implementation must not do anything that will modify 4606** the database connection that invoked the update hook. Any actions 4607** to modify the database connection must be deferred until after the 4608** completion of the [sqlite3_step()] call that triggered the update hook. 4609** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4610** database connections for the meaning of "modify" in this paragraph. 4611** 4612** ^The sqlite3_update_hook(D,C,P) function 4613** returns the P argument from the previous call 4614** on the same [database connection] D, or NULL for 4615** the first call on D. 4616** 4617** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4618** interfaces. 4619*/ 4620void *sqlite3_update_hook( 4621 sqlite3*, 4622 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4623 void* 4624); 4625 4626/* 4627** CAPI3REF: Enable Or Disable Shared Pager Cache 4628** 4629** ^(This routine enables or disables the sharing of the database cache 4630** and schema data structures between [database connection | connections] 4631** to the same database. Sharing is enabled if the argument is true 4632** and disabled if the argument is false.)^ 4633** 4634** ^Cache sharing is enabled and disabled for an entire process. 4635** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4636** sharing was enabled or disabled for each thread separately. 4637** 4638** ^(The cache sharing mode set by this interface effects all subsequent 4639** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4640** Existing database connections continue use the sharing mode 4641** that was in effect at the time they were opened.)^ 4642** 4643** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4644** successfully. An [error code] is returned otherwise.)^ 4645** 4646** ^Shared cache is disabled by default. But this might change in 4647** future releases of SQLite. Applications that care about shared 4648** cache setting should set it explicitly. 4649** 4650** See Also: [SQLite Shared-Cache Mode] 4651*/ 4652int sqlite3_enable_shared_cache(int); 4653 4654/* 4655** CAPI3REF: Attempt To Free Heap Memory 4656** 4657** ^The sqlite3_release_memory() interface attempts to free N bytes 4658** of heap memory by deallocating non-essential memory allocations 4659** held by the database library. Memory used to cache database 4660** pages to improve performance is an example of non-essential memory. 4661** ^sqlite3_release_memory() returns the number of bytes actually freed, 4662** which might be more or less than the amount requested. 4663** ^The sqlite3_release_memory() routine is a no-op returning zero 4664** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4665** 4666** See also: [sqlite3_db_release_memory()] 4667*/ 4668int sqlite3_release_memory(int); 4669 4670/* 4671** CAPI3REF: Free Memory Used By A Database Connection 4672** 4673** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 4674** memory as possible from database connection D. Unlike the 4675** [sqlite3_release_memory()] interface, this interface is effect even 4676** when then [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 4677** omitted. 4678** 4679** See also: [sqlite3_release_memory()] 4680*/ 4681int sqlite3_db_release_memory(sqlite3*); 4682 4683/* 4684** CAPI3REF: Impose A Limit On Heap Size 4685** 4686** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 4687** soft limit on the amount of heap memory that may be allocated by SQLite. 4688** ^SQLite strives to keep heap memory utilization below the soft heap 4689** limit by reducing the number of pages held in the page cache 4690** as heap memory usages approaches the limit. 4691** ^The soft heap limit is "soft" because even though SQLite strives to stay 4692** below the limit, it will exceed the limit rather than generate 4693** an [SQLITE_NOMEM] error. In other words, the soft heap limit 4694** is advisory only. 4695** 4696** ^The return value from sqlite3_soft_heap_limit64() is the size of 4697** the soft heap limit prior to the call, or negative in the case of an 4698** error. ^If the argument N is negative 4699** then no change is made to the soft heap limit. Hence, the current 4700** size of the soft heap limit can be determined by invoking 4701** sqlite3_soft_heap_limit64() with a negative argument. 4702** 4703** ^If the argument N is zero then the soft heap limit is disabled. 4704** 4705** ^(The soft heap limit is not enforced in the current implementation 4706** if one or more of following conditions are true: 4707** 4708** <ul> 4709** <li> The soft heap limit is set to zero. 4710** <li> Memory accounting is disabled using a combination of the 4711** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 4712** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 4713** <li> An alternative page cache implementation is specified using 4714** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 4715** <li> The page cache allocates from its own memory pool supplied 4716** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 4717** from the heap. 4718** </ul>)^ 4719** 4720** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 4721** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 4722** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 4723** the soft heap limit is enforced on every memory allocation. Without 4724** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 4725** when memory is allocated by the page cache. Testing suggests that because 4726** the page cache is the predominate memory user in SQLite, most 4727** applications will achieve adequate soft heap limit enforcement without 4728** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4729** 4730** The circumstances under which SQLite will enforce the soft heap limit may 4731** changes in future releases of SQLite. 4732*/ 4733sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 4734 4735/* 4736** CAPI3REF: Deprecated Soft Heap Limit Interface 4737** DEPRECATED 4738** 4739** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 4740** interface. This routine is provided for historical compatibility 4741** only. All new applications should use the 4742** [sqlite3_soft_heap_limit64()] interface rather than this one. 4743*/ 4744SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 4745 4746 4747/* 4748** CAPI3REF: Extract Metadata About A Column Of A Table 4749** 4750** ^This routine returns metadata about a specific column of a specific 4751** database table accessible using the [database connection] handle 4752** passed as the first function argument. 4753** 4754** ^The column is identified by the second, third and fourth parameters to 4755** this function. ^The second parameter is either the name of the database 4756** (i.e. "main", "temp", or an attached database) containing the specified 4757** table or NULL. ^If it is NULL, then all attached databases are searched 4758** for the table using the same algorithm used by the database engine to 4759** resolve unqualified table references. 4760** 4761** ^The third and fourth parameters to this function are the table and column 4762** name of the desired column, respectively. Neither of these parameters 4763** may be NULL. 4764** 4765** ^Metadata is returned by writing to the memory locations passed as the 5th 4766** and subsequent parameters to this function. ^Any of these arguments may be 4767** NULL, in which case the corresponding element of metadata is omitted. 4768** 4769** ^(<blockquote> 4770** <table border="1"> 4771** <tr><th> Parameter <th> Output<br>Type <th> Description 4772** 4773** <tr><td> 5th <td> const char* <td> Data type 4774** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4775** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4776** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4777** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4778** </table> 4779** </blockquote>)^ 4780** 4781** ^The memory pointed to by the character pointers returned for the 4782** declaration type and collation sequence is valid only until the next 4783** call to any SQLite API function. 4784** 4785** ^If the specified table is actually a view, an [error code] is returned. 4786** 4787** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4788** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4789** parameters are set for the explicitly declared column. ^(If there is no 4790** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4791** parameters are set as follows: 4792** 4793** <pre> 4794** data type: "INTEGER" 4795** collation sequence: "BINARY" 4796** not null: 0 4797** primary key: 1 4798** auto increment: 0 4799** </pre>)^ 4800** 4801** ^(This function may load one or more schemas from database files. If an 4802** error occurs during this process, or if the requested table or column 4803** cannot be found, an [error code] is returned and an error message left 4804** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4805** 4806** ^This API is only available if the library was compiled with the 4807** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4808*/ 4809int sqlite3_table_column_metadata( 4810 sqlite3 *db, /* Connection handle */ 4811 const char *zDbName, /* Database name or NULL */ 4812 const char *zTableName, /* Table name */ 4813 const char *zColumnName, /* Column name */ 4814 char const **pzDataType, /* OUTPUT: Declared data type */ 4815 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4816 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4817 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4818 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4819); 4820 4821/* 4822** CAPI3REF: Load An Extension 4823** 4824** ^This interface loads an SQLite extension library from the named file. 4825** 4826** ^The sqlite3_load_extension() interface attempts to load an 4827** SQLite extension library contained in the file zFile. 4828** 4829** ^The entry point is zProc. 4830** ^zProc may be 0, in which case the name of the entry point 4831** defaults to "sqlite3_extension_init". 4832** ^The sqlite3_load_extension() interface returns 4833** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4834** ^If an error occurs and pzErrMsg is not 0, then the 4835** [sqlite3_load_extension()] interface shall attempt to 4836** fill *pzErrMsg with error message text stored in memory 4837** obtained from [sqlite3_malloc()]. The calling function 4838** should free this memory by calling [sqlite3_free()]. 4839** 4840** ^Extension loading must be enabled using 4841** [sqlite3_enable_load_extension()] prior to calling this API, 4842** otherwise an error will be returned. 4843** 4844** See also the [load_extension() SQL function]. 4845*/ 4846int sqlite3_load_extension( 4847 sqlite3 *db, /* Load the extension into this database connection */ 4848 const char *zFile, /* Name of the shared library containing extension */ 4849 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4850 char **pzErrMsg /* Put error message here if not 0 */ 4851); 4852 4853/* 4854** CAPI3REF: Enable Or Disable Extension Loading 4855** 4856** ^So as not to open security holes in older applications that are 4857** unprepared to deal with extension loading, and as a means of disabling 4858** extension loading while evaluating user-entered SQL, the following API 4859** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4860** 4861** ^Extension loading is off by default. See ticket #1863. 4862** ^Call the sqlite3_enable_load_extension() routine with onoff==1 4863** to turn extension loading on and call it with onoff==0 to turn 4864** it back off again. 4865*/ 4866int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4867 4868/* 4869** CAPI3REF: Automatically Load Statically Linked Extensions 4870** 4871** ^This interface causes the xEntryPoint() function to be invoked for 4872** each new [database connection] that is created. The idea here is that 4873** xEntryPoint() is the entry point for a statically linked SQLite extension 4874** that is to be automatically loaded into all new database connections. 4875** 4876** ^(Even though the function prototype shows that xEntryPoint() takes 4877** no arguments and returns void, SQLite invokes xEntryPoint() with three 4878** arguments and expects and integer result as if the signature of the 4879** entry point where as follows: 4880** 4881** <blockquote><pre> 4882** int xEntryPoint( 4883** sqlite3 *db, 4884** const char **pzErrMsg, 4885** const struct sqlite3_api_routines *pThunk 4886** ); 4887** </pre></blockquote>)^ 4888** 4889** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 4890** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 4891** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 4892** is NULL before calling the xEntryPoint(). ^SQLite will invoke 4893** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 4894** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 4895** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 4896** 4897** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 4898** on the list of automatic extensions is a harmless no-op. ^No entry point 4899** will be called more than once for each database connection that is opened. 4900** 4901** See also: [sqlite3_reset_auto_extension()]. 4902*/ 4903int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4904 4905/* 4906** CAPI3REF: Reset Automatic Extension Loading 4907** 4908** ^This interface disables all automatic extensions previously 4909** registered using [sqlite3_auto_extension()]. 4910*/ 4911void sqlite3_reset_auto_extension(void); 4912 4913/* 4914** The interface to the virtual-table mechanism is currently considered 4915** to be experimental. The interface might change in incompatible ways. 4916** If this is a problem for you, do not use the interface at this time. 4917** 4918** When the virtual-table mechanism stabilizes, we will declare the 4919** interface fixed, support it indefinitely, and remove this comment. 4920*/ 4921 4922/* 4923** Structures used by the virtual table interface 4924*/ 4925typedef struct sqlite3_vtab sqlite3_vtab; 4926typedef struct sqlite3_index_info sqlite3_index_info; 4927typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4928typedef struct sqlite3_module sqlite3_module; 4929 4930/* 4931** CAPI3REF: Virtual Table Object 4932** KEYWORDS: sqlite3_module {virtual table module} 4933** 4934** This structure, sometimes called a "virtual table module", 4935** defines the implementation of a [virtual tables]. 4936** This structure consists mostly of methods for the module. 4937** 4938** ^A virtual table module is created by filling in a persistent 4939** instance of this structure and passing a pointer to that instance 4940** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4941** ^The registration remains valid until it is replaced by a different 4942** module or until the [database connection] closes. The content 4943** of this structure must not change while it is registered with 4944** any database connection. 4945*/ 4946struct sqlite3_module { 4947 int iVersion; 4948 int (*xCreate)(sqlite3*, void *pAux, 4949 int argc, const char *const*argv, 4950 sqlite3_vtab **ppVTab, char**); 4951 int (*xConnect)(sqlite3*, void *pAux, 4952 int argc, const char *const*argv, 4953 sqlite3_vtab **ppVTab, char**); 4954 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4955 int (*xDisconnect)(sqlite3_vtab *pVTab); 4956 int (*xDestroy)(sqlite3_vtab *pVTab); 4957 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4958 int (*xClose)(sqlite3_vtab_cursor*); 4959 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4960 int argc, sqlite3_value **argv); 4961 int (*xNext)(sqlite3_vtab_cursor*); 4962 int (*xEof)(sqlite3_vtab_cursor*); 4963 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4964 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4965 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4966 int (*xBegin)(sqlite3_vtab *pVTab); 4967 int (*xSync)(sqlite3_vtab *pVTab); 4968 int (*xCommit)(sqlite3_vtab *pVTab); 4969 int (*xRollback)(sqlite3_vtab *pVTab); 4970 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4971 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4972 void **ppArg); 4973 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4974 /* The methods above are in version 1 of the sqlite_module object. Those 4975 ** below are for version 2 and greater. */ 4976 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 4977 int (*xRelease)(sqlite3_vtab *pVTab, int); 4978 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 4979}; 4980 4981/* 4982** CAPI3REF: Virtual Table Indexing Information 4983** KEYWORDS: sqlite3_index_info 4984** 4985** The sqlite3_index_info structure and its substructures is used as part 4986** of the [virtual table] interface to 4987** pass information into and receive the reply from the [xBestIndex] 4988** method of a [virtual table module]. The fields under **Inputs** are the 4989** inputs to xBestIndex and are read-only. xBestIndex inserts its 4990** results into the **Outputs** fields. 4991** 4992** ^(The aConstraint[] array records WHERE clause constraints of the form: 4993** 4994** <blockquote>column OP expr</blockquote> 4995** 4996** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 4997** stored in aConstraint[].op using one of the 4998** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 4999** ^(The index of the column is stored in 5000** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5001** expr on the right-hand side can be evaluated (and thus the constraint 5002** is usable) and false if it cannot.)^ 5003** 5004** ^The optimizer automatically inverts terms of the form "expr OP column" 5005** and makes other simplifications to the WHERE clause in an attempt to 5006** get as many WHERE clause terms into the form shown above as possible. 5007** ^The aConstraint[] array only reports WHERE clause terms that are 5008** relevant to the particular virtual table being queried. 5009** 5010** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5011** ^Each term of aOrderBy records a column of the ORDER BY clause. 5012** 5013** The [xBestIndex] method must fill aConstraintUsage[] with information 5014** about what parameters to pass to xFilter. ^If argvIndex>0 then 5015** the right-hand side of the corresponding aConstraint[] is evaluated 5016** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5017** is true, then the constraint is assumed to be fully handled by the 5018** virtual table and is not checked again by SQLite.)^ 5019** 5020** ^The idxNum and idxPtr values are recorded and passed into the 5021** [xFilter] method. 5022** ^[sqlite3_free()] is used to free idxPtr if and only if 5023** needToFreeIdxPtr is true. 5024** 5025** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5026** the correct order to satisfy the ORDER BY clause so that no separate 5027** sorting step is required. 5028** 5029** ^The estimatedCost value is an estimate of the cost of doing the 5030** particular lookup. A full scan of a table with N entries should have 5031** a cost of N. A binary search of a table of N entries should have a 5032** cost of approximately log(N). 5033*/ 5034struct sqlite3_index_info { 5035 /* Inputs */ 5036 int nConstraint; /* Number of entries in aConstraint */ 5037 struct sqlite3_index_constraint { 5038 int iColumn; /* Column on left-hand side of constraint */ 5039 unsigned char op; /* Constraint operator */ 5040 unsigned char usable; /* True if this constraint is usable */ 5041 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5042 } *aConstraint; /* Table of WHERE clause constraints */ 5043 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5044 struct sqlite3_index_orderby { 5045 int iColumn; /* Column number */ 5046 unsigned char desc; /* True for DESC. False for ASC. */ 5047 } *aOrderBy; /* The ORDER BY clause */ 5048 /* Outputs */ 5049 struct sqlite3_index_constraint_usage { 5050 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5051 unsigned char omit; /* Do not code a test for this constraint */ 5052 } *aConstraintUsage; 5053 int idxNum; /* Number used to identify the index */ 5054 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5055 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5056 int orderByConsumed; /* True if output is already ordered */ 5057 double estimatedCost; /* Estimated cost of using this index */ 5058}; 5059 5060/* 5061** CAPI3REF: Virtual Table Constraint Operator Codes 5062** 5063** These macros defined the allowed values for the 5064** [sqlite3_index_info].aConstraint[].op field. Each value represents 5065** an operator that is part of a constraint term in the wHERE clause of 5066** a query that uses a [virtual table]. 5067*/ 5068#define SQLITE_INDEX_CONSTRAINT_EQ 2 5069#define SQLITE_INDEX_CONSTRAINT_GT 4 5070#define SQLITE_INDEX_CONSTRAINT_LE 8 5071#define SQLITE_INDEX_CONSTRAINT_LT 16 5072#define SQLITE_INDEX_CONSTRAINT_GE 32 5073#define SQLITE_INDEX_CONSTRAINT_MATCH 64 5074 5075/* 5076** CAPI3REF: Register A Virtual Table Implementation 5077** 5078** ^These routines are used to register a new [virtual table module] name. 5079** ^Module names must be registered before 5080** creating a new [virtual table] using the module and before using a 5081** preexisting [virtual table] for the module. 5082** 5083** ^The module name is registered on the [database connection] specified 5084** by the first parameter. ^The name of the module is given by the 5085** second parameter. ^The third parameter is a pointer to 5086** the implementation of the [virtual table module]. ^The fourth 5087** parameter is an arbitrary client data pointer that is passed through 5088** into the [xCreate] and [xConnect] methods of the virtual table module 5089** when a new virtual table is be being created or reinitialized. 5090** 5091** ^The sqlite3_create_module_v2() interface has a fifth parameter which 5092** is a pointer to a destructor for the pClientData. ^SQLite will 5093** invoke the destructor function (if it is not NULL) when SQLite 5094** no longer needs the pClientData pointer. ^The destructor will also 5095** be invoked if the call to sqlite3_create_module_v2() fails. 5096** ^The sqlite3_create_module() 5097** interface is equivalent to sqlite3_create_module_v2() with a NULL 5098** destructor. 5099*/ 5100int sqlite3_create_module( 5101 sqlite3 *db, /* SQLite connection to register module with */ 5102 const char *zName, /* Name of the module */ 5103 const sqlite3_module *p, /* Methods for the module */ 5104 void *pClientData /* Client data for xCreate/xConnect */ 5105); 5106int sqlite3_create_module_v2( 5107 sqlite3 *db, /* SQLite connection to register module with */ 5108 const char *zName, /* Name of the module */ 5109 const sqlite3_module *p, /* Methods for the module */ 5110 void *pClientData, /* Client data for xCreate/xConnect */ 5111 void(*xDestroy)(void*) /* Module destructor function */ 5112); 5113 5114/* 5115** CAPI3REF: Virtual Table Instance Object 5116** KEYWORDS: sqlite3_vtab 5117** 5118** Every [virtual table module] implementation uses a subclass 5119** of this object to describe a particular instance 5120** of the [virtual table]. Each subclass will 5121** be tailored to the specific needs of the module implementation. 5122** The purpose of this superclass is to define certain fields that are 5123** common to all module implementations. 5124** 5125** ^Virtual tables methods can set an error message by assigning a 5126** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 5127** take care that any prior string is freed by a call to [sqlite3_free()] 5128** prior to assigning a new string to zErrMsg. ^After the error message 5129** is delivered up to the client application, the string will be automatically 5130** freed by sqlite3_free() and the zErrMsg field will be zeroed. 5131*/ 5132struct sqlite3_vtab { 5133 const sqlite3_module *pModule; /* The module for this virtual table */ 5134 int nRef; /* NO LONGER USED */ 5135 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 5136 /* Virtual table implementations will typically add additional fields */ 5137}; 5138 5139/* 5140** CAPI3REF: Virtual Table Cursor Object 5141** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 5142** 5143** Every [virtual table module] implementation uses a subclass of the 5144** following structure to describe cursors that point into the 5145** [virtual table] and are used 5146** to loop through the virtual table. Cursors are created using the 5147** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 5148** by the [sqlite3_module.xClose | xClose] method. Cursors are used 5149** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 5150** of the module. Each module implementation will define 5151** the content of a cursor structure to suit its own needs. 5152** 5153** This superclass exists in order to define fields of the cursor that 5154** are common to all implementations. 5155*/ 5156struct sqlite3_vtab_cursor { 5157 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 5158 /* Virtual table implementations will typically add additional fields */ 5159}; 5160 5161/* 5162** CAPI3REF: Declare The Schema Of A Virtual Table 5163** 5164** ^The [xCreate] and [xConnect] methods of a 5165** [virtual table module] call this interface 5166** to declare the format (the names and datatypes of the columns) of 5167** the virtual tables they implement. 5168*/ 5169int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 5170 5171/* 5172** CAPI3REF: Overload A Function For A Virtual Table 5173** 5174** ^(Virtual tables can provide alternative implementations of functions 5175** using the [xFindFunction] method of the [virtual table module]. 5176** But global versions of those functions 5177** must exist in order to be overloaded.)^ 5178** 5179** ^(This API makes sure a global version of a function with a particular 5180** name and number of parameters exists. If no such function exists 5181** before this API is called, a new function is created.)^ ^The implementation 5182** of the new function always causes an exception to be thrown. So 5183** the new function is not good for anything by itself. Its only 5184** purpose is to be a placeholder function that can be overloaded 5185** by a [virtual table]. 5186*/ 5187int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5188 5189/* 5190** The interface to the virtual-table mechanism defined above (back up 5191** to a comment remarkably similar to this one) is currently considered 5192** to be experimental. The interface might change in incompatible ways. 5193** If this is a problem for you, do not use the interface at this time. 5194** 5195** When the virtual-table mechanism stabilizes, we will declare the 5196** interface fixed, support it indefinitely, and remove this comment. 5197*/ 5198 5199/* 5200** CAPI3REF: A Handle To An Open BLOB 5201** KEYWORDS: {BLOB handle} {BLOB handles} 5202** 5203** An instance of this object represents an open BLOB on which 5204** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5205** ^Objects of this type are created by [sqlite3_blob_open()] 5206** and destroyed by [sqlite3_blob_close()]. 5207** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5208** can be used to read or write small subsections of the BLOB. 5209** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5210*/ 5211typedef struct sqlite3_blob sqlite3_blob; 5212 5213/* 5214** CAPI3REF: Open A BLOB For Incremental I/O 5215** 5216** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5217** in row iRow, column zColumn, table zTable in database zDb; 5218** in other words, the same BLOB that would be selected by: 5219** 5220** <pre> 5221** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5222** </pre>)^ 5223** 5224** ^If the flags parameter is non-zero, then the BLOB is opened for read 5225** and write access. ^If it is zero, the BLOB is opened for read access. 5226** ^It is not possible to open a column that is part of an index or primary 5227** key for writing. ^If [foreign key constraints] are enabled, it is 5228** not possible to open a column that is part of a [child key] for writing. 5229** 5230** ^Note that the database name is not the filename that contains 5231** the database but rather the symbolic name of the database that 5232** appears after the AS keyword when the database is connected using [ATTACH]. 5233** ^For the main database file, the database name is "main". 5234** ^For TEMP tables, the database name is "temp". 5235** 5236** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 5237** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 5238** to be a null pointer.)^ 5239** ^This function sets the [database connection] error code and message 5240** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 5241** functions. ^Note that the *ppBlob variable is always initialized in a 5242** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 5243** regardless of the success or failure of this routine. 5244** 5245** ^(If the row that a BLOB handle points to is modified by an 5246** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5247** then the BLOB handle is marked as "expired". 5248** This is true if any column of the row is changed, even a column 5249** other than the one the BLOB handle is open on.)^ 5250** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5251** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5252** ^(Changes written into a BLOB prior to the BLOB expiring are not 5253** rolled back by the expiration of the BLOB. Such changes will eventually 5254** commit if the transaction continues to completion.)^ 5255** 5256** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5257** the opened blob. ^The size of a blob may not be changed by this 5258** interface. Use the [UPDATE] SQL command to change the size of a 5259** blob. 5260** 5261** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5262** and the built-in [zeroblob] SQL function can be used, if desired, 5263** to create an empty, zero-filled blob in which to read or write using 5264** this interface. 5265** 5266** To avoid a resource leak, every open [BLOB handle] should eventually 5267** be released by a call to [sqlite3_blob_close()]. 5268*/ 5269int sqlite3_blob_open( 5270 sqlite3*, 5271 const char *zDb, 5272 const char *zTable, 5273 const char *zColumn, 5274 sqlite3_int64 iRow, 5275 int flags, 5276 sqlite3_blob **ppBlob 5277); 5278 5279/* 5280** CAPI3REF: Move a BLOB Handle to a New Row 5281** 5282** ^This function is used to move an existing blob handle so that it points 5283** to a different row of the same database table. ^The new row is identified 5284** by the rowid value passed as the second argument. Only the row can be 5285** changed. ^The database, table and column on which the blob handle is open 5286** remain the same. Moving an existing blob handle to a new row can be 5287** faster than closing the existing handle and opening a new one. 5288** 5289** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5290** it must exist and there must be either a blob or text value stored in 5291** the nominated column.)^ ^If the new row is not present in the table, or if 5292** it does not contain a blob or text value, or if another error occurs, an 5293** SQLite error code is returned and the blob handle is considered aborted. 5294** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5295** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5296** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5297** always returns zero. 5298** 5299** ^This function sets the database handle error code and message. 5300*/ 5301SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5302 5303/* 5304** CAPI3REF: Close A BLOB Handle 5305** 5306** ^Closes an open [BLOB handle]. 5307** 5308** ^Closing a BLOB shall cause the current transaction to commit 5309** if there are no other BLOBs, no pending prepared statements, and the 5310** database connection is in [autocommit mode]. 5311** ^If any writes were made to the BLOB, they might be held in cache 5312** until the close operation if they will fit. 5313** 5314** ^(Closing the BLOB often forces the changes 5315** out to disk and so if any I/O errors occur, they will likely occur 5316** at the time when the BLOB is closed. Any errors that occur during 5317** closing are reported as a non-zero return value.)^ 5318** 5319** ^(The BLOB is closed unconditionally. Even if this routine returns 5320** an error code, the BLOB is still closed.)^ 5321** 5322** ^Calling this routine with a null pointer (such as would be returned 5323** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 5324*/ 5325int sqlite3_blob_close(sqlite3_blob *); 5326 5327/* 5328** CAPI3REF: Return The Size Of An Open BLOB 5329** 5330** ^Returns the size in bytes of the BLOB accessible via the 5331** successfully opened [BLOB handle] in its only argument. ^The 5332** incremental blob I/O routines can only read or overwriting existing 5333** blob content; they cannot change the size of a blob. 5334** 5335** This routine only works on a [BLOB handle] which has been created 5336** by a prior successful call to [sqlite3_blob_open()] and which has not 5337** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5338** to this routine results in undefined and probably undesirable behavior. 5339*/ 5340int sqlite3_blob_bytes(sqlite3_blob *); 5341 5342/* 5343** CAPI3REF: Read Data From A BLOB Incrementally 5344** 5345** ^(This function is used to read data from an open [BLOB handle] into a 5346** caller-supplied buffer. N bytes of data are copied into buffer Z 5347** from the open BLOB, starting at offset iOffset.)^ 5348** 5349** ^If offset iOffset is less than N bytes from the end of the BLOB, 5350** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 5351** less than zero, [SQLITE_ERROR] is returned and no data is read. 5352** ^The size of the blob (and hence the maximum value of N+iOffset) 5353** can be determined using the [sqlite3_blob_bytes()] interface. 5354** 5355** ^An attempt to read from an expired [BLOB handle] fails with an 5356** error code of [SQLITE_ABORT]. 5357** 5358** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 5359** Otherwise, an [error code] or an [extended error code] is returned.)^ 5360** 5361** This routine only works on a [BLOB handle] which has been created 5362** by a prior successful call to [sqlite3_blob_open()] and which has not 5363** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5364** to this routine results in undefined and probably undesirable behavior. 5365** 5366** See also: [sqlite3_blob_write()]. 5367*/ 5368int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 5369 5370/* 5371** CAPI3REF: Write Data Into A BLOB Incrementally 5372** 5373** ^This function is used to write data into an open [BLOB handle] from a 5374** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 5375** into the open BLOB, starting at offset iOffset. 5376** 5377** ^If the [BLOB handle] passed as the first argument was not opened for 5378** writing (the flags parameter to [sqlite3_blob_open()] was zero), 5379** this function returns [SQLITE_READONLY]. 5380** 5381** ^This function may only modify the contents of the BLOB; it is 5382** not possible to increase the size of a BLOB using this API. 5383** ^If offset iOffset is less than N bytes from the end of the BLOB, 5384** [SQLITE_ERROR] is returned and no data is written. ^If N is 5385** less than zero [SQLITE_ERROR] is returned and no data is written. 5386** The size of the BLOB (and hence the maximum value of N+iOffset) 5387** can be determined using the [sqlite3_blob_bytes()] interface. 5388** 5389** ^An attempt to write to an expired [BLOB handle] fails with an 5390** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 5391** before the [BLOB handle] expired are not rolled back by the 5392** expiration of the handle, though of course those changes might 5393** have been overwritten by the statement that expired the BLOB handle 5394** or by other independent statements. 5395** 5396** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 5397** Otherwise, an [error code] or an [extended error code] is returned.)^ 5398** 5399** This routine only works on a [BLOB handle] which has been created 5400** by a prior successful call to [sqlite3_blob_open()] and which has not 5401** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5402** to this routine results in undefined and probably undesirable behavior. 5403** 5404** See also: [sqlite3_blob_read()]. 5405*/ 5406int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 5407 5408/* 5409** CAPI3REF: Virtual File System Objects 5410** 5411** A virtual filesystem (VFS) is an [sqlite3_vfs] object 5412** that SQLite uses to interact 5413** with the underlying operating system. Most SQLite builds come with a 5414** single default VFS that is appropriate for the host computer. 5415** New VFSes can be registered and existing VFSes can be unregistered. 5416** The following interfaces are provided. 5417** 5418** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 5419** ^Names are case sensitive. 5420** ^Names are zero-terminated UTF-8 strings. 5421** ^If there is no match, a NULL pointer is returned. 5422** ^If zVfsName is NULL then the default VFS is returned. 5423** 5424** ^New VFSes are registered with sqlite3_vfs_register(). 5425** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 5426** ^The same VFS can be registered multiple times without injury. 5427** ^To make an existing VFS into the default VFS, register it again 5428** with the makeDflt flag set. If two different VFSes with the 5429** same name are registered, the behavior is undefined. If a 5430** VFS is registered with a name that is NULL or an empty string, 5431** then the behavior is undefined. 5432** 5433** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 5434** ^(If the default VFS is unregistered, another VFS is chosen as 5435** the default. The choice for the new VFS is arbitrary.)^ 5436*/ 5437sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 5438int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 5439int sqlite3_vfs_unregister(sqlite3_vfs*); 5440 5441/* 5442** CAPI3REF: Mutexes 5443** 5444** The SQLite core uses these routines for thread 5445** synchronization. Though they are intended for internal 5446** use by SQLite, code that links against SQLite is 5447** permitted to use any of these routines. 5448** 5449** The SQLite source code contains multiple implementations 5450** of these mutex routines. An appropriate implementation 5451** is selected automatically at compile-time. ^(The following 5452** implementations are available in the SQLite core: 5453** 5454** <ul> 5455** <li> SQLITE_MUTEX_OS2 5456** <li> SQLITE_MUTEX_PTHREADS 5457** <li> SQLITE_MUTEX_W32 5458** <li> SQLITE_MUTEX_NOOP 5459** </ul>)^ 5460** 5461** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 5462** that does no real locking and is appropriate for use in 5463** a single-threaded application. ^The SQLITE_MUTEX_OS2, 5464** SQLITE_MUTEX_PTHREADS, and SQLITE_MUTEX_W32 implementations 5465** are appropriate for use on OS/2, Unix, and Windows. 5466** 5467** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 5468** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 5469** implementation is included with the library. In this case the 5470** application must supply a custom mutex implementation using the 5471** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 5472** before calling sqlite3_initialize() or any other public sqlite3_ 5473** function that calls sqlite3_initialize().)^ 5474** 5475** ^The sqlite3_mutex_alloc() routine allocates a new 5476** mutex and returns a pointer to it. ^If it returns NULL 5477** that means that a mutex could not be allocated. ^SQLite 5478** will unwind its stack and return an error. ^(The argument 5479** to sqlite3_mutex_alloc() is one of these integer constants: 5480** 5481** <ul> 5482** <li> SQLITE_MUTEX_FAST 5483** <li> SQLITE_MUTEX_RECURSIVE 5484** <li> SQLITE_MUTEX_STATIC_MASTER 5485** <li> SQLITE_MUTEX_STATIC_MEM 5486** <li> SQLITE_MUTEX_STATIC_MEM2 5487** <li> SQLITE_MUTEX_STATIC_PRNG 5488** <li> SQLITE_MUTEX_STATIC_LRU 5489** <li> SQLITE_MUTEX_STATIC_LRU2 5490** </ul>)^ 5491** 5492** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 5493** cause sqlite3_mutex_alloc() to create 5494** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 5495** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 5496** The mutex implementation does not need to make a distinction 5497** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 5498** not want to. ^SQLite will only request a recursive mutex in 5499** cases where it really needs one. ^If a faster non-recursive mutex 5500** implementation is available on the host platform, the mutex subsystem 5501** might return such a mutex in response to SQLITE_MUTEX_FAST. 5502** 5503** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 5504** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 5505** a pointer to a static preexisting mutex. ^Six static mutexes are 5506** used by the current version of SQLite. Future versions of SQLite 5507** may add additional static mutexes. Static mutexes are for internal 5508** use by SQLite only. Applications that use SQLite mutexes should 5509** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 5510** SQLITE_MUTEX_RECURSIVE. 5511** 5512** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 5513** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 5514** returns a different mutex on every call. ^But for the static 5515** mutex types, the same mutex is returned on every call that has 5516** the same type number. 5517** 5518** ^The sqlite3_mutex_free() routine deallocates a previously 5519** allocated dynamic mutex. ^SQLite is careful to deallocate every 5520** dynamic mutex that it allocates. The dynamic mutexes must not be in 5521** use when they are deallocated. Attempting to deallocate a static 5522** mutex results in undefined behavior. ^SQLite never deallocates 5523** a static mutex. 5524** 5525** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 5526** to enter a mutex. ^If another thread is already within the mutex, 5527** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 5528** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 5529** upon successful entry. ^(Mutexes created using 5530** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 5531** In such cases the, 5532** mutex must be exited an equal number of times before another thread 5533** can enter.)^ ^(If the same thread tries to enter any other 5534** kind of mutex more than once, the behavior is undefined. 5535** SQLite will never exhibit 5536** such behavior in its own use of mutexes.)^ 5537** 5538** ^(Some systems (for example, Windows 95) do not support the operation 5539** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 5540** will always return SQLITE_BUSY. The SQLite core only ever uses 5541** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 5542** 5543** ^The sqlite3_mutex_leave() routine exits a mutex that was 5544** previously entered by the same thread. ^(The behavior 5545** is undefined if the mutex is not currently entered by the 5546** calling thread or is not currently allocated. SQLite will 5547** never do either.)^ 5548** 5549** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 5550** sqlite3_mutex_leave() is a NULL pointer, then all three routines 5551** behave as no-ops. 5552** 5553** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 5554*/ 5555sqlite3_mutex *sqlite3_mutex_alloc(int); 5556void sqlite3_mutex_free(sqlite3_mutex*); 5557void sqlite3_mutex_enter(sqlite3_mutex*); 5558int sqlite3_mutex_try(sqlite3_mutex*); 5559void sqlite3_mutex_leave(sqlite3_mutex*); 5560 5561/* 5562** CAPI3REF: Mutex Methods Object 5563** 5564** An instance of this structure defines the low-level routines 5565** used to allocate and use mutexes. 5566** 5567** Usually, the default mutex implementations provided by SQLite are 5568** sufficient, however the user has the option of substituting a custom 5569** implementation for specialized deployments or systems for which SQLite 5570** does not provide a suitable implementation. In this case, the user 5571** creates and populates an instance of this structure to pass 5572** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 5573** Additionally, an instance of this structure can be used as an 5574** output variable when querying the system for the current mutex 5575** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 5576** 5577** ^The xMutexInit method defined by this structure is invoked as 5578** part of system initialization by the sqlite3_initialize() function. 5579** ^The xMutexInit routine is called by SQLite exactly once for each 5580** effective call to [sqlite3_initialize()]. 5581** 5582** ^The xMutexEnd method defined by this structure is invoked as 5583** part of system shutdown by the sqlite3_shutdown() function. The 5584** implementation of this method is expected to release all outstanding 5585** resources obtained by the mutex methods implementation, especially 5586** those obtained by the xMutexInit method. ^The xMutexEnd() 5587** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 5588** 5589** ^(The remaining seven methods defined by this structure (xMutexAlloc, 5590** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 5591** xMutexNotheld) implement the following interfaces (respectively): 5592** 5593** <ul> 5594** <li> [sqlite3_mutex_alloc()] </li> 5595** <li> [sqlite3_mutex_free()] </li> 5596** <li> [sqlite3_mutex_enter()] </li> 5597** <li> [sqlite3_mutex_try()] </li> 5598** <li> [sqlite3_mutex_leave()] </li> 5599** <li> [sqlite3_mutex_held()] </li> 5600** <li> [sqlite3_mutex_notheld()] </li> 5601** </ul>)^ 5602** 5603** The only difference is that the public sqlite3_XXX functions enumerated 5604** above silently ignore any invocations that pass a NULL pointer instead 5605** of a valid mutex handle. The implementations of the methods defined 5606** by this structure are not required to handle this case, the results 5607** of passing a NULL pointer instead of a valid mutex handle are undefined 5608** (i.e. it is acceptable to provide an implementation that segfaults if 5609** it is passed a NULL pointer). 5610** 5611** The xMutexInit() method must be threadsafe. ^It must be harmless to 5612** invoke xMutexInit() multiple times within the same process and without 5613** intervening calls to xMutexEnd(). Second and subsequent calls to 5614** xMutexInit() must be no-ops. 5615** 5616** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 5617** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 5618** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 5619** memory allocation for a fast or recursive mutex. 5620** 5621** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 5622** called, but only if the prior call to xMutexInit returned SQLITE_OK. 5623** If xMutexInit fails in any way, it is expected to clean up after itself 5624** prior to returning. 5625*/ 5626typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 5627struct sqlite3_mutex_methods { 5628 int (*xMutexInit)(void); 5629 int (*xMutexEnd)(void); 5630 sqlite3_mutex *(*xMutexAlloc)(int); 5631 void (*xMutexFree)(sqlite3_mutex *); 5632 void (*xMutexEnter)(sqlite3_mutex *); 5633 int (*xMutexTry)(sqlite3_mutex *); 5634 void (*xMutexLeave)(sqlite3_mutex *); 5635 int (*xMutexHeld)(sqlite3_mutex *); 5636 int (*xMutexNotheld)(sqlite3_mutex *); 5637}; 5638 5639/* 5640** CAPI3REF: Mutex Verification Routines 5641** 5642** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 5643** are intended for use inside assert() statements. ^The SQLite core 5644** never uses these routines except inside an assert() and applications 5645** are advised to follow the lead of the core. ^The SQLite core only 5646** provides implementations for these routines when it is compiled 5647** with the SQLITE_DEBUG flag. ^External mutex implementations 5648** are only required to provide these routines if SQLITE_DEBUG is 5649** defined and if NDEBUG is not defined. 5650** 5651** ^These routines should return true if the mutex in their argument 5652** is held or not held, respectively, by the calling thread. 5653** 5654** ^The implementation is not required to provide versions of these 5655** routines that actually work. If the implementation does not provide working 5656** versions of these routines, it should at least provide stubs that always 5657** return true so that one does not get spurious assertion failures. 5658** 5659** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 5660** the routine should return 1. This seems counter-intuitive since 5661** clearly the mutex cannot be held if it does not exist. But 5662** the reason the mutex does not exist is because the build is not 5663** using mutexes. And we do not want the assert() containing the 5664** call to sqlite3_mutex_held() to fail, so a non-zero return is 5665** the appropriate thing to do. ^The sqlite3_mutex_notheld() 5666** interface should also return 1 when given a NULL pointer. 5667*/ 5668#ifndef NDEBUG 5669int sqlite3_mutex_held(sqlite3_mutex*); 5670int sqlite3_mutex_notheld(sqlite3_mutex*); 5671#endif 5672 5673/* 5674** CAPI3REF: Mutex Types 5675** 5676** The [sqlite3_mutex_alloc()] interface takes a single argument 5677** which is one of these integer constants. 5678** 5679** The set of static mutexes may change from one SQLite release to the 5680** next. Applications that override the built-in mutex logic must be 5681** prepared to accommodate additional static mutexes. 5682*/ 5683#define SQLITE_MUTEX_FAST 0 5684#define SQLITE_MUTEX_RECURSIVE 1 5685#define SQLITE_MUTEX_STATIC_MASTER 2 5686#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 5687#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 5688#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 5689#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 5690#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 5691#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 5692#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 5693 5694/* 5695** CAPI3REF: Retrieve the mutex for a database connection 5696** 5697** ^This interface returns a pointer the [sqlite3_mutex] object that 5698** serializes access to the [database connection] given in the argument 5699** when the [threading mode] is Serialized. 5700** ^If the [threading mode] is Single-thread or Multi-thread then this 5701** routine returns a NULL pointer. 5702*/ 5703sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 5704 5705/* 5706** CAPI3REF: Low-Level Control Of Database Files 5707** 5708** ^The [sqlite3_file_control()] interface makes a direct call to the 5709** xFileControl method for the [sqlite3_io_methods] object associated 5710** with a particular database identified by the second argument. ^The 5711** name of the database is "main" for the main database or "temp" for the 5712** TEMP database, or the name that appears after the AS keyword for 5713** databases that are added using the [ATTACH] SQL command. 5714** ^A NULL pointer can be used in place of "main" to refer to the 5715** main database file. 5716** ^The third and fourth parameters to this routine 5717** are passed directly through to the second and third parameters of 5718** the xFileControl method. ^The return value of the xFileControl 5719** method becomes the return value of this routine. 5720** 5721** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 5722** a pointer to the underlying [sqlite3_file] object to be written into 5723** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 5724** case is a short-circuit path which does not actually invoke the 5725** underlying sqlite3_io_methods.xFileControl method. 5726** 5727** ^If the second parameter (zDbName) does not match the name of any 5728** open database file, then SQLITE_ERROR is returned. ^This error 5729** code is not remembered and will not be recalled by [sqlite3_errcode()] 5730** or [sqlite3_errmsg()]. The underlying xFileControl method might 5731** also return SQLITE_ERROR. There is no way to distinguish between 5732** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5733** xFileControl method. 5734** 5735** See also: [SQLITE_FCNTL_LOCKSTATE] 5736*/ 5737int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5738 5739/* 5740** CAPI3REF: Testing Interface 5741** 5742** ^The sqlite3_test_control() interface is used to read out internal 5743** state of SQLite and to inject faults into SQLite for testing 5744** purposes. ^The first parameter is an operation code that determines 5745** the number, meaning, and operation of all subsequent parameters. 5746** 5747** This interface is not for use by applications. It exists solely 5748** for verifying the correct operation of the SQLite library. Depending 5749** on how the SQLite library is compiled, this interface might not exist. 5750** 5751** The details of the operation codes, their meanings, the parameters 5752** they take, and what they do are all subject to change without notice. 5753** Unlike most of the SQLite API, this function is not guaranteed to 5754** operate consistently from one release to the next. 5755*/ 5756int sqlite3_test_control(int op, ...); 5757 5758/* 5759** CAPI3REF: Testing Interface Operation Codes 5760** 5761** These constants are the valid operation code parameters used 5762** as the first argument to [sqlite3_test_control()]. 5763** 5764** These parameters and their meanings are subject to change 5765** without notice. These values are for testing purposes only. 5766** Applications should not use any of these parameters or the 5767** [sqlite3_test_control()] interface. 5768*/ 5769#define SQLITE_TESTCTRL_FIRST 5 5770#define SQLITE_TESTCTRL_PRNG_SAVE 5 5771#define SQLITE_TESTCTRL_PRNG_RESTORE 6 5772#define SQLITE_TESTCTRL_PRNG_RESET 7 5773#define SQLITE_TESTCTRL_BITVEC_TEST 8 5774#define SQLITE_TESTCTRL_FAULT_INSTALL 9 5775#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5776#define SQLITE_TESTCTRL_PENDING_BYTE 11 5777#define SQLITE_TESTCTRL_ASSERT 12 5778#define SQLITE_TESTCTRL_ALWAYS 13 5779#define SQLITE_TESTCTRL_RESERVE 14 5780#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 5781#define SQLITE_TESTCTRL_ISKEYWORD 16 5782#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 5783#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 5784#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 5785#define SQLITE_TESTCTRL_LAST 19 5786 5787/* 5788** CAPI3REF: SQLite Runtime Status 5789** 5790** ^This interface is used to retrieve runtime status information 5791** about the performance of SQLite, and optionally to reset various 5792** highwater marks. ^The first argument is an integer code for 5793** the specific parameter to measure. ^(Recognized integer codes 5794** are of the form [status parameters | SQLITE_STATUS_...].)^ 5795** ^The current value of the parameter is returned into *pCurrent. 5796** ^The highest recorded value is returned in *pHighwater. ^If the 5797** resetFlag is true, then the highest record value is reset after 5798** *pHighwater is written. ^(Some parameters do not record the highest 5799** value. For those parameters 5800** nothing is written into *pHighwater and the resetFlag is ignored.)^ 5801** ^(Other parameters record only the highwater mark and not the current 5802** value. For these latter parameters nothing is written into *pCurrent.)^ 5803** 5804** ^The sqlite3_status() routine returns SQLITE_OK on success and a 5805** non-zero [error code] on failure. 5806** 5807** This routine is threadsafe but is not atomic. This routine can be 5808** called while other threads are running the same or different SQLite 5809** interfaces. However the values returned in *pCurrent and 5810** *pHighwater reflect the status of SQLite at different points in time 5811** and it is possible that another thread might change the parameter 5812** in between the times when *pCurrent and *pHighwater are written. 5813** 5814** See also: [sqlite3_db_status()] 5815*/ 5816int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 5817 5818 5819/* 5820** CAPI3REF: Status Parameters 5821** KEYWORDS: {status parameters} 5822** 5823** These integer constants designate various run-time status parameters 5824** that can be returned by [sqlite3_status()]. 5825** 5826** <dl> 5827** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 5828** <dd>This parameter is the current amount of memory checked out 5829** using [sqlite3_malloc()], either directly or indirectly. The 5830** figure includes calls made to [sqlite3_malloc()] by the application 5831** and internal memory usage by the SQLite library. Scratch memory 5832** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 5833** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 5834** this parameter. The amount returned is the sum of the allocation 5835** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 5836** 5837** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 5838** <dd>This parameter records the largest memory allocation request 5839** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 5840** internal equivalents). Only the value returned in the 5841** *pHighwater parameter to [sqlite3_status()] is of interest. 5842** The value written into the *pCurrent parameter is undefined.</dd>)^ 5843** 5844** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 5845** <dd>This parameter records the number of separate memory allocations 5846** currently checked out.</dd>)^ 5847** 5848** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 5849** <dd>This parameter returns the number of pages used out of the 5850** [pagecache memory allocator] that was configured using 5851** [SQLITE_CONFIG_PAGECACHE]. The 5852** value returned is in pages, not in bytes.</dd>)^ 5853** 5854** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 5855** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5856** <dd>This parameter returns the number of bytes of page cache 5857** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 5858** buffer and where forced to overflow to [sqlite3_malloc()]. The 5859** returned value includes allocations that overflowed because they 5860** where too large (they were larger than the "sz" parameter to 5861** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 5862** no space was left in the page cache.</dd>)^ 5863** 5864** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 5865** <dd>This parameter records the largest memory allocation request 5866** handed to [pagecache memory allocator]. Only the value returned in the 5867** *pHighwater parameter to [sqlite3_status()] is of interest. 5868** The value written into the *pCurrent parameter is undefined.</dd>)^ 5869** 5870** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 5871** <dd>This parameter returns the number of allocations used out of the 5872** [scratch memory allocator] configured using 5873** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5874** in bytes. Since a single thread may only have one scratch allocation 5875** outstanding at time, this parameter also reports the number of threads 5876** using scratch memory at the same time.</dd>)^ 5877** 5878** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5879** <dd>This parameter returns the number of bytes of scratch memory 5880** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 5881** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5882** returned include overflows because the requested allocation was too 5883** larger (that is, because the requested allocation was larger than the 5884** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5885** slots were available. 5886** </dd>)^ 5887** 5888** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5889** <dd>This parameter records the largest memory allocation request 5890** handed to [scratch memory allocator]. Only the value returned in the 5891** *pHighwater parameter to [sqlite3_status()] is of interest. 5892** The value written into the *pCurrent parameter is undefined.</dd>)^ 5893** 5894** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 5895** <dd>This parameter records the deepest parser stack. It is only 5896** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 5897** </dl> 5898** 5899** New status parameters may be added from time to time. 5900*/ 5901#define SQLITE_STATUS_MEMORY_USED 0 5902#define SQLITE_STATUS_PAGECACHE_USED 1 5903#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5904#define SQLITE_STATUS_SCRATCH_USED 3 5905#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5906#define SQLITE_STATUS_MALLOC_SIZE 5 5907#define SQLITE_STATUS_PARSER_STACK 6 5908#define SQLITE_STATUS_PAGECACHE_SIZE 7 5909#define SQLITE_STATUS_SCRATCH_SIZE 8 5910#define SQLITE_STATUS_MALLOC_COUNT 9 5911 5912/* 5913** CAPI3REF: Database Connection Status 5914** 5915** ^This interface is used to retrieve runtime status information 5916** about a single [database connection]. ^The first argument is the 5917** database connection object to be interrogated. ^The second argument 5918** is an integer constant, taken from the set of 5919** [SQLITE_DBSTATUS options], that 5920** determines the parameter to interrogate. The set of 5921** [SQLITE_DBSTATUS options] is likely 5922** to grow in future releases of SQLite. 5923** 5924** ^The current value of the requested parameter is written into *pCur 5925** and the highest instantaneous value is written into *pHiwtr. ^If 5926** the resetFlg is true, then the highest instantaneous value is 5927** reset back down to the current value. 5928** 5929** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 5930** non-zero [error code] on failure. 5931** 5932** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5933*/ 5934int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5935 5936/* 5937** CAPI3REF: Status Parameters for database connections 5938** KEYWORDS: {SQLITE_DBSTATUS options} 5939** 5940** These constants are the available integer "verbs" that can be passed as 5941** the second argument to the [sqlite3_db_status()] interface. 5942** 5943** New verbs may be added in future releases of SQLite. Existing verbs 5944** might be discontinued. Applications should check the return code from 5945** [sqlite3_db_status()] to make sure that the call worked. 5946** The [sqlite3_db_status()] interface will return a non-zero error code 5947** if a discontinued or unsupported verb is invoked. 5948** 5949** <dl> 5950** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5951** <dd>This parameter returns the number of lookaside memory slots currently 5952** checked out.</dd>)^ 5953** 5954** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 5955** <dd>This parameter returns the number malloc attempts that were 5956** satisfied using lookaside memory. Only the high-water value is meaningful; 5957** the current value is always zero.)^ 5958** 5959** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 5960** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 5961** <dd>This parameter returns the number malloc attempts that might have 5962** been satisfied using lookaside memory but failed due to the amount of 5963** memory requested being larger than the lookaside slot size. 5964** Only the high-water value is meaningful; 5965** the current value is always zero.)^ 5966** 5967** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 5968** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 5969** <dd>This parameter returns the number malloc attempts that might have 5970** been satisfied using lookaside memory but failed due to all lookaside 5971** memory already being in use. 5972** Only the high-water value is meaningful; 5973** the current value is always zero.)^ 5974** 5975** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 5976** <dd>This parameter returns the approximate number of of bytes of heap 5977** memory used by all pager caches associated with the database connection.)^ 5978** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 5979** 5980** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 5981** <dd>This parameter returns the approximate number of of bytes of heap 5982** memory used to store the schema for all databases associated 5983** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 5984** ^The full amount of memory used by the schemas is reported, even if the 5985** schema memory is shared with other database connections due to 5986** [shared cache mode] being enabled. 5987** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 5988** 5989** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 5990** <dd>This parameter returns the approximate number of of bytes of heap 5991** and lookaside memory used by all prepared statements associated with 5992** the database connection.)^ 5993** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 5994** </dd> 5995** 5996** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 5997** <dd>This parameter returns the number of pager cache hits that have 5998** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 5999** is always 0. 6000** </dd> 6001** 6002** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6003** <dd>This parameter returns the number of pager cache misses that have 6004** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6005** is always 0. 6006** </dd> 6007** 6008** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 6009** <dd>This parameter returns the number of dirty cache entries that have 6010** been written to disk. Specifically, the number of pages written to the 6011** wal file in wal mode databases, or the number of pages written to the 6012** database file in rollback mode databases. Any pages written as part of 6013** transaction rollback or database recovery operations are not included. 6014** If an IO or other error occurs while writing a page to disk, the effect 6015** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 6016** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 6017** </dd> 6018** </dl> 6019*/ 6020#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6021#define SQLITE_DBSTATUS_CACHE_USED 1 6022#define SQLITE_DBSTATUS_SCHEMA_USED 2 6023#define SQLITE_DBSTATUS_STMT_USED 3 6024#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6025#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6026#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 6027#define SQLITE_DBSTATUS_CACHE_HIT 7 6028#define SQLITE_DBSTATUS_CACHE_MISS 8 6029#define SQLITE_DBSTATUS_CACHE_WRITE 9 6030#define SQLITE_DBSTATUS_MAX 9 /* Largest defined DBSTATUS */ 6031 6032 6033/* 6034** CAPI3REF: Prepared Statement Status 6035** 6036** ^(Each prepared statement maintains various 6037** [SQLITE_STMTSTATUS counters] that measure the number 6038** of times it has performed specific operations.)^ These counters can 6039** be used to monitor the performance characteristics of the prepared 6040** statements. For example, if the number of table steps greatly exceeds 6041** the number of table searches or result rows, that would tend to indicate 6042** that the prepared statement is using a full table scan rather than 6043** an index. 6044** 6045** ^(This interface is used to retrieve and reset counter values from 6046** a [prepared statement]. The first argument is the prepared statement 6047** object to be interrogated. The second argument 6048** is an integer code for a specific [SQLITE_STMTSTATUS counter] 6049** to be interrogated.)^ 6050** ^The current value of the requested counter is returned. 6051** ^If the resetFlg is true, then the counter is reset to zero after this 6052** interface call returns. 6053** 6054** See also: [sqlite3_status()] and [sqlite3_db_status()]. 6055*/ 6056int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 6057 6058/* 6059** CAPI3REF: Status Parameters for prepared statements 6060** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 6061** 6062** These preprocessor macros define integer codes that name counter 6063** values associated with the [sqlite3_stmt_status()] interface. 6064** The meanings of the various counters are as follows: 6065** 6066** <dl> 6067** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 6068** <dd>^This is the number of times that SQLite has stepped forward in 6069** a table as part of a full table scan. Large numbers for this counter 6070** may indicate opportunities for performance improvement through 6071** careful use of indices.</dd> 6072** 6073** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 6074** <dd>^This is the number of sort operations that have occurred. 6075** A non-zero value in this counter may indicate an opportunity to 6076** improvement performance through careful use of indices.</dd> 6077** 6078** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 6079** <dd>^This is the number of rows inserted into transient indices that 6080** were created automatically in order to help joins run faster. 6081** A non-zero value in this counter may indicate an opportunity to 6082** improvement performance by adding permanent indices that do not 6083** need to be reinitialized each time the statement is run.</dd> 6084** </dl> 6085*/ 6086#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 6087#define SQLITE_STMTSTATUS_SORT 2 6088#define SQLITE_STMTSTATUS_AUTOINDEX 3 6089 6090/* 6091** CAPI3REF: Custom Page Cache Object 6092** 6093** The sqlite3_pcache type is opaque. It is implemented by 6094** the pluggable module. The SQLite core has no knowledge of 6095** its size or internal structure and never deals with the 6096** sqlite3_pcache object except by holding and passing pointers 6097** to the object. 6098** 6099** See [sqlite3_pcache_methods2] for additional information. 6100*/ 6101typedef struct sqlite3_pcache sqlite3_pcache; 6102 6103/* 6104** CAPI3REF: Custom Page Cache Object 6105** 6106** The sqlite3_pcache_page object represents a single page in the 6107** page cache. The page cache will allocate instances of this 6108** object. Various methods of the page cache use pointers to instances 6109** of this object as parameters or as their return value. 6110** 6111** See [sqlite3_pcache_methods2] for additional information. 6112*/ 6113typedef struct sqlite3_pcache_page sqlite3_pcache_page; 6114struct sqlite3_pcache_page { 6115 void *pBuf; /* The content of the page */ 6116 void *pExtra; /* Extra information associated with the page */ 6117}; 6118 6119/* 6120** CAPI3REF: Application Defined Page Cache. 6121** KEYWORDS: {page cache} 6122** 6123** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 6124** register an alternative page cache implementation by passing in an 6125** instance of the sqlite3_pcache_methods2 structure.)^ 6126** In many applications, most of the heap memory allocated by 6127** SQLite is used for the page cache. 6128** By implementing a 6129** custom page cache using this API, an application can better control 6130** the amount of memory consumed by SQLite, the way in which 6131** that memory is allocated and released, and the policies used to 6132** determine exactly which parts of a database file are cached and for 6133** how long. 6134** 6135** The alternative page cache mechanism is an 6136** extreme measure that is only needed by the most demanding applications. 6137** The built-in page cache is recommended for most uses. 6138** 6139** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 6140** internal buffer by SQLite within the call to [sqlite3_config]. Hence 6141** the application may discard the parameter after the call to 6142** [sqlite3_config()] returns.)^ 6143** 6144** [[the xInit() page cache method]] 6145** ^(The xInit() method is called once for each effective 6146** call to [sqlite3_initialize()])^ 6147** (usually only once during the lifetime of the process). ^(The xInit() 6148** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 6149** The intent of the xInit() method is to set up global data structures 6150** required by the custom page cache implementation. 6151** ^(If the xInit() method is NULL, then the 6152** built-in default page cache is used instead of the application defined 6153** page cache.)^ 6154** 6155** [[the xShutdown() page cache method]] 6156** ^The xShutdown() method is called by [sqlite3_shutdown()]. 6157** It can be used to clean up 6158** any outstanding resources before process shutdown, if required. 6159** ^The xShutdown() method may be NULL. 6160** 6161** ^SQLite automatically serializes calls to the xInit method, 6162** so the xInit method need not be threadsafe. ^The 6163** xShutdown method is only called from [sqlite3_shutdown()] so it does 6164** not need to be threadsafe either. All other methods must be threadsafe 6165** in multithreaded applications. 6166** 6167** ^SQLite will never invoke xInit() more than once without an intervening 6168** call to xShutdown(). 6169** 6170** [[the xCreate() page cache methods]] 6171** ^SQLite invokes the xCreate() method to construct a new cache instance. 6172** SQLite will typically create one cache instance for each open database file, 6173** though this is not guaranteed. ^The 6174** first parameter, szPage, is the size in bytes of the pages that must 6175** be allocated by the cache. ^szPage will always a power of two. ^The 6176** second parameter szExtra is a number of bytes of extra storage 6177** associated with each page cache entry. ^The szExtra parameter will 6178** a number less than 250. SQLite will use the 6179** extra szExtra bytes on each page to store metadata about the underlying 6180** database page on disk. The value passed into szExtra depends 6181** on the SQLite version, the target platform, and how SQLite was compiled. 6182** ^The third argument to xCreate(), bPurgeable, is true if the cache being 6183** created will be used to cache database pages of a file stored on disk, or 6184** false if it is used for an in-memory database. The cache implementation 6185** does not have to do anything special based with the value of bPurgeable; 6186** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 6187** never invoke xUnpin() except to deliberately delete a page. 6188** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 6189** false will always have the "discard" flag set to true. 6190** ^Hence, a cache created with bPurgeable false will 6191** never contain any unpinned pages. 6192** 6193** [[the xCachesize() page cache method]] 6194** ^(The xCachesize() method may be called at any time by SQLite to set the 6195** suggested maximum cache-size (number of pages stored by) the cache 6196** instance passed as the first argument. This is the value configured using 6197** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 6198** parameter, the implementation is not required to do anything with this 6199** value; it is advisory only. 6200** 6201** [[the xPagecount() page cache methods]] 6202** The xPagecount() method must return the number of pages currently 6203** stored in the cache, both pinned and unpinned. 6204** 6205** [[the xFetch() page cache methods]] 6206** The xFetch() method locates a page in the cache and returns a pointer to 6207** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 6208** The pBuf element of the returned sqlite3_pcache_page object will be a 6209** pointer to a buffer of szPage bytes used to store the content of a 6210** single database page. The pExtra element of sqlite3_pcache_page will be 6211** a pointer to the szExtra bytes of extra storage that SQLite has requested 6212** for each entry in the page cache. 6213** 6214** The page to be fetched is determined by the key. ^The minimum key value 6215** is 1. After it has been retrieved using xFetch, the page is considered 6216** to be "pinned". 6217** 6218** If the requested page is already in the page cache, then the page cache 6219** implementation must return a pointer to the page buffer with its content 6220** intact. If the requested page is not already in the cache, then the 6221** cache implementation should use the value of the createFlag 6222** parameter to help it determined what action to take: 6223** 6224** <table border=1 width=85% align=center> 6225** <tr><th> createFlag <th> Behaviour when page is not already in cache 6226** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6227** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6228** Otherwise return NULL. 6229** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6230** NULL if allocating a new page is effectively impossible. 6231** </table> 6232** 6233** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6234** will only use a createFlag of 2 after a prior call with a createFlag of 1 6235** failed.)^ In between the to xFetch() calls, SQLite may 6236** attempt to unpin one or more cache pages by spilling the content of 6237** pinned pages to disk and synching the operating system disk cache. 6238** 6239** [[the xUnpin() page cache method]] 6240** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6241** as its second argument. If the third parameter, discard, is non-zero, 6242** then the page must be evicted from the cache. 6243** ^If the discard parameter is 6244** zero, then the page may be discarded or retained at the discretion of 6245** page cache implementation. ^The page cache implementation 6246** may choose to evict unpinned pages at any time. 6247** 6248** The cache must not perform any reference counting. A single 6249** call to xUnpin() unpins the page regardless of the number of prior calls 6250** to xFetch(). 6251** 6252** [[the xRekey() page cache methods]] 6253** The xRekey() method is used to change the key value associated with the 6254** page passed as the second argument. If the cache 6255** previously contains an entry associated with newKey, it must be 6256** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6257** to be pinned. 6258** 6259** When SQLite calls the xTruncate() method, the cache must discard all 6260** existing cache entries with page numbers (keys) greater than or equal 6261** to the value of the iLimit parameter passed to xTruncate(). If any 6262** of these pages are pinned, they are implicitly unpinned, meaning that 6263** they can be safely discarded. 6264** 6265** [[the xDestroy() page cache method]] 6266** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6267** All resources associated with the specified cache should be freed. ^After 6268** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6269** handle invalid, and will not use it with any other sqlite3_pcache_methods2 6270** functions. 6271** 6272** [[the xShrink() page cache method]] 6273** ^SQLite invokes the xShrink() method when it wants the page cache to 6274** free up as much of heap memory as possible. The page cache implementation 6275** is not obligated to free any memory, but well-behaved implementations should 6276** do their best. 6277*/ 6278typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 6279struct sqlite3_pcache_methods2 { 6280 int iVersion; 6281 void *pArg; 6282 int (*xInit)(void*); 6283 void (*xShutdown)(void*); 6284 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 6285 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6286 int (*xPagecount)(sqlite3_pcache*); 6287 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6288 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 6289 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 6290 unsigned oldKey, unsigned newKey); 6291 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6292 void (*xDestroy)(sqlite3_pcache*); 6293 void (*xShrink)(sqlite3_pcache*); 6294}; 6295 6296/* 6297** This is the obsolete pcache_methods object that has now been replaced 6298** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 6299** retained in the header file for backwards compatibility only. 6300*/ 6301typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 6302struct sqlite3_pcache_methods { 6303 void *pArg; 6304 int (*xInit)(void*); 6305 void (*xShutdown)(void*); 6306 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 6307 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6308 int (*xPagecount)(sqlite3_pcache*); 6309 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6310 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 6311 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 6312 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6313 void (*xDestroy)(sqlite3_pcache*); 6314}; 6315 6316 6317/* 6318** CAPI3REF: Online Backup Object 6319** 6320** The sqlite3_backup object records state information about an ongoing 6321** online backup operation. ^The sqlite3_backup object is created by 6322** a call to [sqlite3_backup_init()] and is destroyed by a call to 6323** [sqlite3_backup_finish()]. 6324** 6325** See Also: [Using the SQLite Online Backup API] 6326*/ 6327typedef struct sqlite3_backup sqlite3_backup; 6328 6329/* 6330** CAPI3REF: Online Backup API. 6331** 6332** The backup API copies the content of one database into another. 6333** It is useful either for creating backups of databases or 6334** for copying in-memory databases to or from persistent files. 6335** 6336** See Also: [Using the SQLite Online Backup API] 6337** 6338** ^SQLite holds a write transaction open on the destination database file 6339** for the duration of the backup operation. 6340** ^The source database is read-locked only while it is being read; 6341** it is not locked continuously for the entire backup operation. 6342** ^Thus, the backup may be performed on a live source database without 6343** preventing other database connections from 6344** reading or writing to the source database while the backup is underway. 6345** 6346** ^(To perform a backup operation: 6347** <ol> 6348** <li><b>sqlite3_backup_init()</b> is called once to initialize the 6349** backup, 6350** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 6351** the data between the two databases, and finally 6352** <li><b>sqlite3_backup_finish()</b> is called to release all resources 6353** associated with the backup operation. 6354** </ol>)^ 6355** There should be exactly one call to sqlite3_backup_finish() for each 6356** successful call to sqlite3_backup_init(). 6357** 6358** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 6359** 6360** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 6361** [database connection] associated with the destination database 6362** and the database name, respectively. 6363** ^The database name is "main" for the main database, "temp" for the 6364** temporary database, or the name specified after the AS keyword in 6365** an [ATTACH] statement for an attached database. 6366** ^The S and M arguments passed to 6367** sqlite3_backup_init(D,N,S,M) identify the [database connection] 6368** and database name of the source database, respectively. 6369** ^The source and destination [database connections] (parameters S and D) 6370** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 6371** an error. 6372** 6373** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 6374** returned and an error code and error message are stored in the 6375** destination [database connection] D. 6376** ^The error code and message for the failed call to sqlite3_backup_init() 6377** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 6378** [sqlite3_errmsg16()] functions. 6379** ^A successful call to sqlite3_backup_init() returns a pointer to an 6380** [sqlite3_backup] object. 6381** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 6382** sqlite3_backup_finish() functions to perform the specified backup 6383** operation. 6384** 6385** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 6386** 6387** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 6388** the source and destination databases specified by [sqlite3_backup] object B. 6389** ^If N is negative, all remaining source pages are copied. 6390** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 6391** are still more pages to be copied, then the function returns [SQLITE_OK]. 6392** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 6393** from source to destination, then it returns [SQLITE_DONE]. 6394** ^If an error occurs while running sqlite3_backup_step(B,N), 6395** then an [error code] is returned. ^As well as [SQLITE_OK] and 6396** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 6397** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 6398** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 6399** 6400** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 6401** <ol> 6402** <li> the destination database was opened read-only, or 6403** <li> the destination database is using write-ahead-log journaling 6404** and the destination and source page sizes differ, or 6405** <li> the destination database is an in-memory database and the 6406** destination and source page sizes differ. 6407** </ol>)^ 6408** 6409** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 6410** the [sqlite3_busy_handler | busy-handler function] 6411** is invoked (if one is specified). ^If the 6412** busy-handler returns non-zero before the lock is available, then 6413** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 6414** sqlite3_backup_step() can be retried later. ^If the source 6415** [database connection] 6416** is being used to write to the source database when sqlite3_backup_step() 6417** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 6418** case the call to sqlite3_backup_step() can be retried later on. ^(If 6419** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 6420** [SQLITE_READONLY] is returned, then 6421** there is no point in retrying the call to sqlite3_backup_step(). These 6422** errors are considered fatal.)^ The application must accept 6423** that the backup operation has failed and pass the backup operation handle 6424** to the sqlite3_backup_finish() to release associated resources. 6425** 6426** ^The first call to sqlite3_backup_step() obtains an exclusive lock 6427** on the destination file. ^The exclusive lock is not released until either 6428** sqlite3_backup_finish() is called or the backup operation is complete 6429** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 6430** sqlite3_backup_step() obtains a [shared lock] on the source database that 6431** lasts for the duration of the sqlite3_backup_step() call. 6432** ^Because the source database is not locked between calls to 6433** sqlite3_backup_step(), the source database may be modified mid-way 6434** through the backup process. ^If the source database is modified by an 6435** external process or via a database connection other than the one being 6436** used by the backup operation, then the backup will be automatically 6437** restarted by the next call to sqlite3_backup_step(). ^If the source 6438** database is modified by the using the same database connection as is used 6439** by the backup operation, then the backup database is automatically 6440** updated at the same time. 6441** 6442** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 6443** 6444** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 6445** application wishes to abandon the backup operation, the application 6446** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 6447** ^The sqlite3_backup_finish() interfaces releases all 6448** resources associated with the [sqlite3_backup] object. 6449** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 6450** active write-transaction on the destination database is rolled back. 6451** The [sqlite3_backup] object is invalid 6452** and may not be used following a call to sqlite3_backup_finish(). 6453** 6454** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 6455** sqlite3_backup_step() errors occurred, regardless or whether or not 6456** sqlite3_backup_step() completed. 6457** ^If an out-of-memory condition or IO error occurred during any prior 6458** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 6459** sqlite3_backup_finish() returns the corresponding [error code]. 6460** 6461** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 6462** is not a permanent error and does not affect the return value of 6463** sqlite3_backup_finish(). 6464** 6465** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]] 6466** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 6467** 6468** ^Each call to sqlite3_backup_step() sets two values inside 6469** the [sqlite3_backup] object: the number of pages still to be backed 6470** up and the total number of pages in the source database file. 6471** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 6472** retrieve these two values, respectively. 6473** 6474** ^The values returned by these functions are only updated by 6475** sqlite3_backup_step(). ^If the source database is modified during a backup 6476** operation, then the values are not updated to account for any extra 6477** pages that need to be updated or the size of the source database file 6478** changing. 6479** 6480** <b>Concurrent Usage of Database Handles</b> 6481** 6482** ^The source [database connection] may be used by the application for other 6483** purposes while a backup operation is underway or being initialized. 6484** ^If SQLite is compiled and configured to support threadsafe database 6485** connections, then the source database connection may be used concurrently 6486** from within other threads. 6487** 6488** However, the application must guarantee that the destination 6489** [database connection] is not passed to any other API (by any thread) after 6490** sqlite3_backup_init() is called and before the corresponding call to 6491** sqlite3_backup_finish(). SQLite does not currently check to see 6492** if the application incorrectly accesses the destination [database connection] 6493** and so no error code is reported, but the operations may malfunction 6494** nevertheless. Use of the destination database connection while a 6495** backup is in progress might also also cause a mutex deadlock. 6496** 6497** If running in [shared cache mode], the application must 6498** guarantee that the shared cache used by the destination database 6499** is not accessed while the backup is running. In practice this means 6500** that the application must guarantee that the disk file being 6501** backed up to is not accessed by any connection within the process, 6502** not just the specific connection that was passed to sqlite3_backup_init(). 6503** 6504** The [sqlite3_backup] object itself is partially threadsafe. Multiple 6505** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 6506** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 6507** APIs are not strictly speaking threadsafe. If they are invoked at the 6508** same time as another thread is invoking sqlite3_backup_step() it is 6509** possible that they return invalid values. 6510*/ 6511sqlite3_backup *sqlite3_backup_init( 6512 sqlite3 *pDest, /* Destination database handle */ 6513 const char *zDestName, /* Destination database name */ 6514 sqlite3 *pSource, /* Source database handle */ 6515 const char *zSourceName /* Source database name */ 6516); 6517int sqlite3_backup_step(sqlite3_backup *p, int nPage); 6518int sqlite3_backup_finish(sqlite3_backup *p); 6519int sqlite3_backup_remaining(sqlite3_backup *p); 6520int sqlite3_backup_pagecount(sqlite3_backup *p); 6521 6522/* 6523** CAPI3REF: Unlock Notification 6524** 6525** ^When running in shared-cache mode, a database operation may fail with 6526** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 6527** individual tables within the shared-cache cannot be obtained. See 6528** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 6529** ^This API may be used to register a callback that SQLite will invoke 6530** when the connection currently holding the required lock relinquishes it. 6531** ^This API is only available if the library was compiled with the 6532** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 6533** 6534** See Also: [Using the SQLite Unlock Notification Feature]. 6535** 6536** ^Shared-cache locks are released when a database connection concludes 6537** its current transaction, either by committing it or rolling it back. 6538** 6539** ^When a connection (known as the blocked connection) fails to obtain a 6540** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 6541** identity of the database connection (the blocking connection) that 6542** has locked the required resource is stored internally. ^After an 6543** application receives an SQLITE_LOCKED error, it may call the 6544** sqlite3_unlock_notify() method with the blocked connection handle as 6545** the first argument to register for a callback that will be invoked 6546** when the blocking connections current transaction is concluded. ^The 6547** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 6548** call that concludes the blocking connections transaction. 6549** 6550** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 6551** there is a chance that the blocking connection will have already 6552** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 6553** If this happens, then the specified callback is invoked immediately, 6554** from within the call to sqlite3_unlock_notify().)^ 6555** 6556** ^If the blocked connection is attempting to obtain a write-lock on a 6557** shared-cache table, and more than one other connection currently holds 6558** a read-lock on the same table, then SQLite arbitrarily selects one of 6559** the other connections to use as the blocking connection. 6560** 6561** ^(There may be at most one unlock-notify callback registered by a 6562** blocked connection. If sqlite3_unlock_notify() is called when the 6563** blocked connection already has a registered unlock-notify callback, 6564** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 6565** called with a NULL pointer as its second argument, then any existing 6566** unlock-notify callback is canceled. ^The blocked connections 6567** unlock-notify callback may also be canceled by closing the blocked 6568** connection using [sqlite3_close()]. 6569** 6570** The unlock-notify callback is not reentrant. If an application invokes 6571** any sqlite3_xxx API functions from within an unlock-notify callback, a 6572** crash or deadlock may be the result. 6573** 6574** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 6575** returns SQLITE_OK. 6576** 6577** <b>Callback Invocation Details</b> 6578** 6579** When an unlock-notify callback is registered, the application provides a 6580** single void* pointer that is passed to the callback when it is invoked. 6581** However, the signature of the callback function allows SQLite to pass 6582** it an array of void* context pointers. The first argument passed to 6583** an unlock-notify callback is a pointer to an array of void* pointers, 6584** and the second is the number of entries in the array. 6585** 6586** When a blocking connections transaction is concluded, there may be 6587** more than one blocked connection that has registered for an unlock-notify 6588** callback. ^If two or more such blocked connections have specified the 6589** same callback function, then instead of invoking the callback function 6590** multiple times, it is invoked once with the set of void* context pointers 6591** specified by the blocked connections bundled together into an array. 6592** This gives the application an opportunity to prioritize any actions 6593** related to the set of unblocked database connections. 6594** 6595** <b>Deadlock Detection</b> 6596** 6597** Assuming that after registering for an unlock-notify callback a 6598** database waits for the callback to be issued before taking any further 6599** action (a reasonable assumption), then using this API may cause the 6600** application to deadlock. For example, if connection X is waiting for 6601** connection Y's transaction to be concluded, and similarly connection 6602** Y is waiting on connection X's transaction, then neither connection 6603** will proceed and the system may remain deadlocked indefinitely. 6604** 6605** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 6606** detection. ^If a given call to sqlite3_unlock_notify() would put the 6607** system in a deadlocked state, then SQLITE_LOCKED is returned and no 6608** unlock-notify callback is registered. The system is said to be in 6609** a deadlocked state if connection A has registered for an unlock-notify 6610** callback on the conclusion of connection B's transaction, and connection 6611** B has itself registered for an unlock-notify callback when connection 6612** A's transaction is concluded. ^Indirect deadlock is also detected, so 6613** the system is also considered to be deadlocked if connection B has 6614** registered for an unlock-notify callback on the conclusion of connection 6615** C's transaction, where connection C is waiting on connection A. ^Any 6616** number of levels of indirection are allowed. 6617** 6618** <b>The "DROP TABLE" Exception</b> 6619** 6620** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 6621** always appropriate to call sqlite3_unlock_notify(). There is however, 6622** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 6623** SQLite checks if there are any currently executing SELECT statements 6624** that belong to the same connection. If there are, SQLITE_LOCKED is 6625** returned. In this case there is no "blocking connection", so invoking 6626** sqlite3_unlock_notify() results in the unlock-notify callback being 6627** invoked immediately. If the application then re-attempts the "DROP TABLE" 6628** or "DROP INDEX" query, an infinite loop might be the result. 6629** 6630** One way around this problem is to check the extended error code returned 6631** by an sqlite3_step() call. ^(If there is a blocking connection, then the 6632** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 6633** the special "DROP TABLE/INDEX" case, the extended error code is just 6634** SQLITE_LOCKED.)^ 6635*/ 6636int sqlite3_unlock_notify( 6637 sqlite3 *pBlocked, /* Waiting connection */ 6638 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 6639 void *pNotifyArg /* Argument to pass to xNotify */ 6640); 6641 6642 6643/* 6644** CAPI3REF: String Comparison 6645** 6646** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 6647** and extensions to compare the contents of two buffers containing UTF-8 6648** strings in a case-independent fashion, using the same definition of "case 6649** independence" that SQLite uses internally when comparing identifiers. 6650*/ 6651int sqlite3_stricmp(const char *, const char *); 6652int sqlite3_strnicmp(const char *, const char *, int); 6653 6654/* 6655** CAPI3REF: Error Logging Interface 6656** 6657** ^The [sqlite3_log()] interface writes a message into the error log 6658** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 6659** ^If logging is enabled, the zFormat string and subsequent arguments are 6660** used with [sqlite3_snprintf()] to generate the final output string. 6661** 6662** The sqlite3_log() interface is intended for use by extensions such as 6663** virtual tables, collating functions, and SQL functions. While there is 6664** nothing to prevent an application from calling sqlite3_log(), doing so 6665** is considered bad form. 6666** 6667** The zFormat string must not be NULL. 6668** 6669** To avoid deadlocks and other threading problems, the sqlite3_log() routine 6670** will not use dynamically allocated memory. The log message is stored in 6671** a fixed-length buffer on the stack. If the log message is longer than 6672** a few hundred characters, it will be truncated to the length of the 6673** buffer. 6674*/ 6675void sqlite3_log(int iErrCode, const char *zFormat, ...); 6676 6677/* 6678** CAPI3REF: Write-Ahead Log Commit Hook 6679** 6680** ^The [sqlite3_wal_hook()] function is used to register a callback that 6681** will be invoked each time a database connection commits data to a 6682** [write-ahead log] (i.e. whenever a transaction is committed in 6683** [journal_mode | journal_mode=WAL mode]). 6684** 6685** ^The callback is invoked by SQLite after the commit has taken place and 6686** the associated write-lock on the database released, so the implementation 6687** may read, write or [checkpoint] the database as required. 6688** 6689** ^The first parameter passed to the callback function when it is invoked 6690** is a copy of the third parameter passed to sqlite3_wal_hook() when 6691** registering the callback. ^The second is a copy of the database handle. 6692** ^The third parameter is the name of the database that was written to - 6693** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 6694** is the number of pages currently in the write-ahead log file, 6695** including those that were just committed. 6696** 6697** The callback function should normally return [SQLITE_OK]. ^If an error 6698** code is returned, that error will propagate back up through the 6699** SQLite code base to cause the statement that provoked the callback 6700** to report an error, though the commit will have still occurred. If the 6701** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 6702** that does not correspond to any valid SQLite error code, the results 6703** are undefined. 6704** 6705** A single database handle may have at most a single write-ahead log callback 6706** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 6707** previously registered write-ahead log callback. ^Note that the 6708** [sqlite3_wal_autocheckpoint()] interface and the 6709** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 6710** those overwrite any prior [sqlite3_wal_hook()] settings. 6711*/ 6712void *sqlite3_wal_hook( 6713 sqlite3*, 6714 int(*)(void *,sqlite3*,const char*,int), 6715 void* 6716); 6717 6718/* 6719** CAPI3REF: Configure an auto-checkpoint 6720** 6721** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 6722** [sqlite3_wal_hook()] that causes any database on [database connection] D 6723** to automatically [checkpoint] 6724** after committing a transaction if there are N or 6725** more frames in the [write-ahead log] file. ^Passing zero or 6726** a negative value as the nFrame parameter disables automatic 6727** checkpoints entirely. 6728** 6729** ^The callback registered by this function replaces any existing callback 6730** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 6731** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 6732** configured by this function. 6733** 6734** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 6735** from SQL. 6736** 6737** ^Every new [database connection] defaults to having the auto-checkpoint 6738** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 6739** pages. The use of this interface 6740** is only necessary if the default setting is found to be suboptimal 6741** for a particular application. 6742*/ 6743int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 6744 6745/* 6746** CAPI3REF: Checkpoint a database 6747** 6748** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 6749** on [database connection] D to be [checkpointed]. ^If X is NULL or an 6750** empty string, then a checkpoint is run on all databases of 6751** connection D. ^If the database connection D is not in 6752** [WAL | write-ahead log mode] then this interface is a harmless no-op. 6753** 6754** ^The [wal_checkpoint pragma] can be used to invoke this interface 6755** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 6756** [wal_autocheckpoint pragma] can be used to cause this interface to be 6757** run whenever the WAL reaches a certain size threshold. 6758** 6759** See also: [sqlite3_wal_checkpoint_v2()] 6760*/ 6761int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 6762 6763/* 6764** CAPI3REF: Checkpoint a database 6765** 6766** Run a checkpoint operation on WAL database zDb attached to database 6767** handle db. The specific operation is determined by the value of the 6768** eMode parameter: 6769** 6770** <dl> 6771** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 6772** Checkpoint as many frames as possible without waiting for any database 6773** readers or writers to finish. Sync the db file if all frames in the log 6774** are checkpointed. This mode is the same as calling 6775** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked. 6776** 6777** <dt>SQLITE_CHECKPOINT_FULL<dd> 6778** This mode blocks (calls the busy-handler callback) until there is no 6779** database writer and all readers are reading from the most recent database 6780** snapshot. It then checkpoints all frames in the log file and syncs the 6781** database file. This call blocks database writers while it is running, 6782** but not database readers. 6783** 6784** <dt>SQLITE_CHECKPOINT_RESTART<dd> 6785** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after 6786** checkpointing the log file it blocks (calls the busy-handler callback) 6787** until all readers are reading from the database file only. This ensures 6788** that the next client to write to the database file restarts the log file 6789** from the beginning. This call blocks database writers while it is running, 6790** but not database readers. 6791** </dl> 6792** 6793** If pnLog is not NULL, then *pnLog is set to the total number of frames in 6794** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to 6795** the total number of checkpointed frames (including any that were already 6796** checkpointed when this function is called). *pnLog and *pnCkpt may be 6797** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK. 6798** If no values are available because of an error, they are both set to -1 6799** before returning to communicate this to the caller. 6800** 6801** All calls obtain an exclusive "checkpoint" lock on the database file. If 6802** any other process is running a checkpoint operation at the same time, the 6803** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a 6804** busy-handler configured, it will not be invoked in this case. 6805** 6806** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive 6807** "writer" lock on the database file. If the writer lock cannot be obtained 6808** immediately, and a busy-handler is configured, it is invoked and the writer 6809** lock retried until either the busy-handler returns 0 or the lock is 6810** successfully obtained. The busy-handler is also invoked while waiting for 6811** database readers as described above. If the busy-handler returns 0 before 6812** the writer lock is obtained or while waiting for database readers, the 6813** checkpoint operation proceeds from that point in the same way as 6814** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 6815** without blocking any further. SQLITE_BUSY is returned in this case. 6816** 6817** If parameter zDb is NULL or points to a zero length string, then the 6818** specified operation is attempted on all WAL databases. In this case the 6819** values written to output parameters *pnLog and *pnCkpt are undefined. If 6820** an SQLITE_BUSY error is encountered when processing one or more of the 6821** attached WAL databases, the operation is still attempted on any remaining 6822** attached databases and SQLITE_BUSY is returned to the caller. If any other 6823** error occurs while processing an attached database, processing is abandoned 6824** and the error code returned to the caller immediately. If no error 6825** (SQLITE_BUSY or otherwise) is encountered while processing the attached 6826** databases, SQLITE_OK is returned. 6827** 6828** If database zDb is the name of an attached database that is not in WAL 6829** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If 6830** zDb is not NULL (or a zero length string) and is not the name of any 6831** attached database, SQLITE_ERROR is returned to the caller. 6832*/ 6833int sqlite3_wal_checkpoint_v2( 6834 sqlite3 *db, /* Database handle */ 6835 const char *zDb, /* Name of attached database (or NULL) */ 6836 int eMode, /* SQLITE_CHECKPOINT_* value */ 6837 int *pnLog, /* OUT: Size of WAL log in frames */ 6838 int *pnCkpt /* OUT: Total number of frames checkpointed */ 6839); 6840 6841/* 6842** CAPI3REF: Checkpoint operation parameters 6843** 6844** These constants can be used as the 3rd parameter to 6845** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()] 6846** documentation for additional information about the meaning and use of 6847** each of these values. 6848*/ 6849#define SQLITE_CHECKPOINT_PASSIVE 0 6850#define SQLITE_CHECKPOINT_FULL 1 6851#define SQLITE_CHECKPOINT_RESTART 2 6852 6853/* 6854** CAPI3REF: Virtual Table Interface Configuration 6855** 6856** This function may be called by either the [xConnect] or [xCreate] method 6857** of a [virtual table] implementation to configure 6858** various facets of the virtual table interface. 6859** 6860** If this interface is invoked outside the context of an xConnect or 6861** xCreate virtual table method then the behavior is undefined. 6862** 6863** At present, there is only one option that may be configured using 6864** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 6865** may be added in the future. 6866*/ 6867int sqlite3_vtab_config(sqlite3*, int op, ...); 6868 6869/* 6870** CAPI3REF: Virtual Table Configuration Options 6871** 6872** These macros define the various options to the 6873** [sqlite3_vtab_config()] interface that [virtual table] implementations 6874** can use to customize and optimize their behavior. 6875** 6876** <dl> 6877** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 6878** <dd>Calls of the form 6879** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 6880** where X is an integer. If X is zero, then the [virtual table] whose 6881** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 6882** support constraints. In this configuration (which is the default) if 6883** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 6884** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 6885** specified as part of the users SQL statement, regardless of the actual 6886** ON CONFLICT mode specified. 6887** 6888** If X is non-zero, then the virtual table implementation guarantees 6889** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 6890** any modifications to internal or persistent data structures have been made. 6891** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 6892** is able to roll back a statement or database transaction, and abandon 6893** or continue processing the current SQL statement as appropriate. 6894** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 6895** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 6896** had been ABORT. 6897** 6898** Virtual table implementations that are required to handle OR REPLACE 6899** must do so within the [xUpdate] method. If a call to the 6900** [sqlite3_vtab_on_conflict()] function indicates that the current ON 6901** CONFLICT policy is REPLACE, the virtual table implementation should 6902** silently replace the appropriate rows within the xUpdate callback and 6903** return SQLITE_OK. Or, if this is not possible, it may return 6904** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 6905** constraint handling. 6906** </dl> 6907*/ 6908#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 6909 6910/* 6911** CAPI3REF: Determine The Virtual Table Conflict Policy 6912** 6913** This function may only be called from within a call to the [xUpdate] method 6914** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 6915** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 6916** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 6917** of the SQL statement that triggered the call to the [xUpdate] method of the 6918** [virtual table]. 6919*/ 6920int sqlite3_vtab_on_conflict(sqlite3 *); 6921 6922/* 6923** CAPI3REF: Conflict resolution modes 6924** 6925** These constants are returned by [sqlite3_vtab_on_conflict()] to 6926** inform a [virtual table] implementation what the [ON CONFLICT] mode 6927** is for the SQL statement being evaluated. 6928** 6929** Note that the [SQLITE_IGNORE] constant is also used as a potential 6930** return value from the [sqlite3_set_authorizer()] callback and that 6931** [SQLITE_ABORT] is also a [result code]. 6932*/ 6933#define SQLITE_ROLLBACK 1 6934/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 6935#define SQLITE_FAIL 3 6936/* #define SQLITE_ABORT 4 // Also an error code */ 6937#define SQLITE_REPLACE 5 6938 6939 6940 6941/* 6942** Undo the hack that converts floating point types to integer for 6943** builds on processors without floating point support. 6944*/ 6945#ifdef SQLITE_OMIT_FLOATING_POINT 6946# undef double 6947#endif 6948 6949#ifdef __cplusplus 6950} /* End of the 'extern "C"' block */ 6951#endif 6952#endif 6953