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