1/* 2** 2001 September 15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are suppose to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef _SQLITE3_H_ 34#define _SQLITE3_H_ 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Add the ability to override 'extern' 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51 52/* 53** These no-op macros are used in front of interfaces to mark those 54** interfaces as either deprecated or experimental. New applications 55** should not use deprecated interfaces - they are support for backwards 56** compatibility only. Application writers should be aware that 57** experimental interfaces are subject to change in point releases. 58** 59** These macros used to resolve to various kinds of compiler magic that 60** would generate warning messages when they were used. But that 61** compiler magic ended up generating such a flurry of bug reports 62** that we have taken it all out and gone back to using simple 63** noop macros. 64*/ 65#define SQLITE_DEPRECATED 66#define SQLITE_EXPERIMENTAL 67 68/* 69** Ensure these symbols were not defined by some previous header file. 70*/ 71#ifdef SQLITE_VERSION 72# undef SQLITE_VERSION 73#endif 74#ifdef SQLITE_VERSION_NUMBER 75# undef SQLITE_VERSION_NUMBER 76#endif 77 78/* 79** CAPI3REF: Compile-Time Library Version Numbers 80** 81** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 82** evaluates to a string literal that is the SQLite version in the 83** format "X.Y.Z" where X is the major version number (always 3 for 84** SQLite3) and Y is the minor version number and Z is the release number.)^ 85** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 86** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 87** numbers used in [SQLITE_VERSION].)^ 88** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 89** be larger than the release from which it is derived. Either Y will 90** be held constant and Z will be incremented or else Y will be incremented 91** and Z will be reset to zero. 92** 93** Since version 3.6.18, SQLite source code has been stored in the 94** <a href="http://www.fossil-scm.org/">Fossil configuration management 95** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 96** a string which identifies a particular check-in of SQLite 97** within its configuration management system. ^The SQLITE_SOURCE_ID 98** string contains the date and time of the check-in (UTC) and an SHA1 99** hash of the entire source tree. 100** 101** See also: [sqlite3_libversion()], 102** [sqlite3_libversion_number()], [sqlite3_sourceid()], 103** [sqlite_version()] and [sqlite_source_id()]. 104*/ 105#define SQLITE_VERSION "--VERS--" 106#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 107#define SQLITE_SOURCE_ID "--SOURCE-ID--" 108 109/* 110** CAPI3REF: Run-Time Library Version Numbers 111** KEYWORDS: sqlite3_version, sqlite3_sourceid 112** 113** These interfaces provide the same information as the [SQLITE_VERSION], 114** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 115** but are associated with the library instead of the header file. ^(Cautious 116** programmers might include assert() statements in their application to 117** verify that values returned by these interfaces match the macros in 118** the header, and thus insure that the application is 119** compiled with matching library and header files. 120** 121** <blockquote><pre> 122** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 123** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 124** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 125** </pre></blockquote>)^ 126** 127** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 128** macro. ^The sqlite3_libversion() function returns a pointer to the 129** to the sqlite3_version[] string constant. The sqlite3_libversion() 130** function is provided for use in DLLs since DLL users usually do not have 131** direct access to string constants within the DLL. ^The 132** sqlite3_libversion_number() function returns an integer equal to 133** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 134** a pointer to a string constant whose value is the same as the 135** [SQLITE_SOURCE_ID] C preprocessor macro. 136** 137** See also: [sqlite_version()] and [sqlite_source_id()]. 138*/ 139SQLITE_EXTERN const char sqlite3_version[]; 140const char *sqlite3_libversion(void); 141const char *sqlite3_sourceid(void); 142int sqlite3_libversion_number(void); 143 144/* 145** CAPI3REF: Run-Time Library Compilation Options Diagnostics 146** 147** ^The sqlite3_compileoption_used() function returns 0 or 1 148** indicating whether the specified option was defined at 149** compile time. ^The SQLITE_ prefix may be omitted from the 150** option name passed to sqlite3_compileoption_used(). 151** 152** ^The sqlite3_compileoption_get() function allows iterating 153** over the list of options that were defined at compile time by 154** returning the N-th compile time option string. ^If N is out of range, 155** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 156** prefix is omitted from any strings returned by 157** sqlite3_compileoption_get(). 158** 159** ^Support for the diagnostic functions sqlite3_compileoption_used() 160** and sqlite3_compileoption_get() may be omitted by specifying the 161** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 162** 163** See also: SQL functions [sqlite_compileoption_used()] and 164** [sqlite_compileoption_get()] and the [compile_options pragma]. 165*/ 166#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 167int sqlite3_compileoption_used(const char *zOptName); 168const char *sqlite3_compileoption_get(int N); 169#endif 170 171/* 172** CAPI3REF: Test To See If The Library Is Threadsafe 173** 174** ^The sqlite3_threadsafe() function returns zero if and only if 175** SQLite was compiled with mutexing code omitted due to the 176** [SQLITE_THREADSAFE] compile-time option being set to 0. 177** 178** SQLite can be compiled with or without mutexes. When 179** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 180** are enabled and SQLite is threadsafe. When the 181** [SQLITE_THREADSAFE] macro is 0, 182** the mutexes are omitted. Without the mutexes, it is not safe 183** to use SQLite concurrently from more than one thread. 184** 185** Enabling mutexes incurs a measurable performance penalty. 186** So if speed is of utmost importance, it makes sense to disable 187** the mutexes. But for maximum safety, mutexes should be enabled. 188** ^The default behavior is for mutexes to be enabled. 189** 190** This interface can be used by an application to make sure that the 191** version of SQLite that it is linking against was compiled with 192** the desired setting of the [SQLITE_THREADSAFE] macro. 193** 194** This interface only reports on the compile-time mutex setting 195** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 196** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 197** can be fully or partially disabled using a call to [sqlite3_config()] 198** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 199** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the 200** sqlite3_threadsafe() function shows only the compile-time setting of 201** thread safety, not any run-time changes to that setting made by 202** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 203** is unchanged by calls to sqlite3_config().)^ 204** 205** See the [threading mode] documentation for additional information. 206*/ 207int sqlite3_threadsafe(void); 208 209/* 210** CAPI3REF: Database Connection Handle 211** KEYWORDS: {database connection} {database connections} 212** 213** Each open SQLite database is represented by a pointer to an instance of 214** the opaque structure named "sqlite3". It is useful to think of an sqlite3 215** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 216** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 217** and [sqlite3_close_v2()] are its destructors. There are many other 218** interfaces (such as 219** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 220** [sqlite3_busy_timeout()] to name but three) that are methods on an 221** sqlite3 object. 222*/ 223typedef struct sqlite3 sqlite3; 224 225/* 226** CAPI3REF: 64-Bit Integer Types 227** KEYWORDS: sqlite_int64 sqlite_uint64 228** 229** Because there is no cross-platform way to specify 64-bit integer types 230** SQLite includes typedefs for 64-bit signed and unsigned integers. 231** 232** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 233** The sqlite_int64 and sqlite_uint64 types are supported for backwards 234** compatibility only. 235** 236** ^The sqlite3_int64 and sqlite_int64 types can store integer values 237** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 238** sqlite3_uint64 and sqlite_uint64 types can store integer values 239** between 0 and +18446744073709551615 inclusive. 240*/ 241#ifdef SQLITE_INT64_TYPE 242 typedef SQLITE_INT64_TYPE sqlite_int64; 243 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 244#elif defined(_MSC_VER) || defined(__BORLANDC__) 245 typedef __int64 sqlite_int64; 246 typedef unsigned __int64 sqlite_uint64; 247#else 248 typedef long long int sqlite_int64; 249 typedef unsigned long long int sqlite_uint64; 250#endif 251typedef sqlite_int64 sqlite3_int64; 252typedef sqlite_uint64 sqlite3_uint64; 253 254/* 255** If compiling for a processor that lacks floating point support, 256** substitute integer for floating-point. 257*/ 258#ifdef SQLITE_OMIT_FLOATING_POINT 259# define double sqlite3_int64 260#endif 261 262/* 263** CAPI3REF: Closing A Database Connection 264** 265** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 266** for the [sqlite3] object. 267** ^Calls to sqlite3_close() and sqlite3_close_v2() return SQLITE_OK if 268** the [sqlite3] object is successfully destroyed and all associated 269** resources are deallocated. 270** 271** ^If the database connection is associated with unfinalized prepared 272** statements or unfinished sqlite3_backup objects then sqlite3_close() 273** will leave the database connection open and return [SQLITE_BUSY]. 274** ^If sqlite3_close_v2() is called with unfinalized prepared statements 275** and unfinished sqlite3_backups, then the database connection becomes 276** an unusable "zombie" which will automatically be deallocated when the 277** last prepared statement is finalized or the last sqlite3_backup is 278** finished. The sqlite3_close_v2() interface is intended for use with 279** host languages that are garbage collected, and where the order in which 280** destructors are called is arbitrary. 281** 282** Applications should [sqlite3_finalize | finalize] all [prepared statements], 283** [sqlite3_blob_close | close] all [BLOB handles], and 284** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 285** with the [sqlite3] object prior to attempting to close the object. ^If 286** sqlite3_close_v2() is called on a [database connection] that still has 287** outstanding [prepared statements], [BLOB handles], and/or 288** [sqlite3_backup] objects then it returns SQLITE_OK but the deallocation 289** of resources is deferred until all [prepared statements], [BLOB handles], 290** and [sqlite3_backup] objects are also destroyed. 291** 292** ^If an [sqlite3] object is destroyed while a transaction is open, 293** the transaction is automatically rolled back. 294** 295** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 296** must be either a NULL 297** pointer or an [sqlite3] object pointer obtained 298** from [sqlite3_open()], [sqlite3_open16()], or 299** [sqlite3_open_v2()], and not previously closed. 300** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 301** argument is a harmless no-op. 302*/ 303int sqlite3_close(sqlite3*); 304int sqlite3_close_v2(sqlite3*); 305 306/* 307** The type for a callback function. 308** This is legacy and deprecated. It is included for historical 309** compatibility and is not documented. 310*/ 311typedef int (*sqlite3_callback)(void*,int,char**, char**); 312 313/* 314** CAPI3REF: One-Step Query Execution Interface 315** 316** The sqlite3_exec() interface is a convenience wrapper around 317** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 318** that allows an application to run multiple statements of SQL 319** without having to use a lot of C code. 320** 321** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 322** semicolon-separate SQL statements passed into its 2nd argument, 323** in the context of the [database connection] passed in as its 1st 324** argument. ^If the callback function of the 3rd argument to 325** sqlite3_exec() is not NULL, then it is invoked for each result row 326** coming out of the evaluated SQL statements. ^The 4th argument to 327** sqlite3_exec() is relayed through to the 1st argument of each 328** callback invocation. ^If the callback pointer to sqlite3_exec() 329** is NULL, then no callback is ever invoked and result rows are 330** ignored. 331** 332** ^If an error occurs while evaluating the SQL statements passed into 333** sqlite3_exec(), then execution of the current statement stops and 334** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 335** is not NULL then any error message is written into memory obtained 336** from [sqlite3_malloc()] and passed back through the 5th parameter. 337** To avoid memory leaks, the application should invoke [sqlite3_free()] 338** on error message strings returned through the 5th parameter of 339** of sqlite3_exec() after the error message string is no longer needed. 340** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 341** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 342** NULL before returning. 343** 344** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 345** routine returns SQLITE_ABORT without invoking the callback again and 346** without running any subsequent SQL statements. 347** 348** ^The 2nd argument to the sqlite3_exec() callback function is the 349** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 350** callback is an array of pointers to strings obtained as if from 351** [sqlite3_column_text()], one for each column. ^If an element of a 352** result row is NULL then the corresponding string pointer for the 353** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 354** sqlite3_exec() callback is an array of pointers to strings where each 355** entry represents the name of corresponding result column as obtained 356** from [sqlite3_column_name()]. 357** 358** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 359** to an empty string, or a pointer that contains only whitespace and/or 360** SQL comments, then no SQL statements are evaluated and the database 361** is not changed. 362** 363** Restrictions: 364** 365** <ul> 366** <li> The application must insure that the 1st parameter to sqlite3_exec() 367** is a valid and open [database connection]. 368** <li> The application must not close [database connection] specified by 369** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 370** <li> The application must not modify the SQL statement text passed into 371** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 372** </ul> 373*/ 374int sqlite3_exec( 375 sqlite3*, /* An open database */ 376 const char *sql, /* SQL to be evaluated */ 377 int (*callback)(void*,int,char**,char**), /* Callback function */ 378 void *, /* 1st argument to callback */ 379 char **errmsg /* Error msg written here */ 380); 381 382/* 383** CAPI3REF: Result Codes 384** KEYWORDS: SQLITE_OK {error code} {error codes} 385** KEYWORDS: {result code} {result codes} 386** 387** Many SQLite functions return an integer result code from the set shown 388** here in order to indicate success or failure. 389** 390** New error codes may be added in future versions of SQLite. 391** 392** See also: [SQLITE_IOERR_READ | extended result codes], 393** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes]. 394*/ 395#define SQLITE_OK 0 /* Successful result */ 396/* beginning-of-error-codes */ 397#define SQLITE_ERROR 1 /* SQL error or missing database */ 398#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 399#define SQLITE_PERM 3 /* Access permission denied */ 400#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 401#define SQLITE_BUSY 5 /* The database file is locked */ 402#define SQLITE_LOCKED 6 /* A table in the database is locked */ 403#define SQLITE_NOMEM 7 /* A malloc() failed */ 404#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 405#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 406#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 407#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 408#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 409#define SQLITE_FULL 13 /* Insertion failed because database is full */ 410#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 411#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 412#define SQLITE_EMPTY 16 /* Database is empty */ 413#define SQLITE_SCHEMA 17 /* The database schema changed */ 414#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 415#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 416#define SQLITE_MISMATCH 20 /* Data type mismatch */ 417#define SQLITE_MISUSE 21 /* Library used incorrectly */ 418#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 419#define SQLITE_AUTH 23 /* Authorization denied */ 420#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 421#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 422#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 423#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 424#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 425#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 426#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 427/* end-of-error-codes */ 428 429/* 430** CAPI3REF: Extended Result Codes 431** KEYWORDS: {extended error code} {extended error codes} 432** KEYWORDS: {extended result code} {extended result codes} 433** 434** In its default configuration, SQLite API routines return one of 26 integer 435** [SQLITE_OK | result codes]. However, experience has shown that many of 436** these result codes are too coarse-grained. They do not provide as 437** much information about problems as programmers might like. In an effort to 438** address this, newer versions of SQLite (version 3.3.8 and later) include 439** support for additional result codes that provide more detailed information 440** about errors. The extended result codes are enabled or disabled 441** on a per database connection basis using the 442** [sqlite3_extended_result_codes()] API. 443** 444** Some of the available extended result codes are listed here. 445** One may expect the number of extended result codes will be expand 446** over time. Software that uses extended result codes should expect 447** to see new result codes in future releases of SQLite. 448** 449** The SQLITE_OK result code will never be extended. It will always 450** be exactly zero. 451*/ 452#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 453#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 454#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 455#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 456#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 457#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 458#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 459#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 460#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 461#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 462#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 463#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 464#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 465#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 466#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 467#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 468#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 469#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 470#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 471#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 472#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 473#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 474#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 475#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 476#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 477#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 478#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 479#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 480#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 481#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 482#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 483#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 484#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 485#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 486#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 487#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 488#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 489#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 490#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 491#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 492#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 493#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 494#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 495#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 496#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 497 498/* 499** CAPI3REF: Flags For File Open Operations 500** 501** These bit values are intended for use in the 502** 3rd parameter to the [sqlite3_open_v2()] interface and 503** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 504*/ 505#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 506#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 507#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 508#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 509#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 510#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 511#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 512#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 513#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 514#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 515#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 516#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 517#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 518#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 519#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 520#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 521#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 522#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 523#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 524#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 525 526/* Reserved: 0x00F00000 */ 527 528/* 529** CAPI3REF: Device Characteristics 530** 531** The xDeviceCharacteristics method of the [sqlite3_io_methods] 532** object returns an integer which is a vector of these 533** bit values expressing I/O characteristics of the mass storage 534** device that holds the file that the [sqlite3_io_methods] 535** refers to. 536** 537** The SQLITE_IOCAP_ATOMIC property means that all writes of 538** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 539** mean that writes of blocks that are nnn bytes in size and 540** are aligned to an address which is an integer multiple of 541** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 542** that when data is appended to a file, the data is appended 543** first then the size of the file is extended, never the other 544** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 545** information is written to disk in the same order as calls 546** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 547** after reboot following a crash or power loss, the only bytes in a 548** file that were written at the application level might have changed 549** and that adjacent bytes, even bytes within the same sector are 550** guaranteed to be unchanged. 551*/ 552#define SQLITE_IOCAP_ATOMIC 0x00000001 553#define SQLITE_IOCAP_ATOMIC512 0x00000002 554#define SQLITE_IOCAP_ATOMIC1K 0x00000004 555#define SQLITE_IOCAP_ATOMIC2K 0x00000008 556#define SQLITE_IOCAP_ATOMIC4K 0x00000010 557#define SQLITE_IOCAP_ATOMIC8K 0x00000020 558#define SQLITE_IOCAP_ATOMIC16K 0x00000040 559#define SQLITE_IOCAP_ATOMIC32K 0x00000080 560#define SQLITE_IOCAP_ATOMIC64K 0x00000100 561#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 562#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 563#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 564#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 565 566/* 567** CAPI3REF: File Locking Levels 568** 569** SQLite uses one of these integer values as the second 570** argument to calls it makes to the xLock() and xUnlock() methods 571** of an [sqlite3_io_methods] object. 572*/ 573#define SQLITE_LOCK_NONE 0 574#define SQLITE_LOCK_SHARED 1 575#define SQLITE_LOCK_RESERVED 2 576#define SQLITE_LOCK_PENDING 3 577#define SQLITE_LOCK_EXCLUSIVE 4 578 579/* 580** CAPI3REF: Synchronization Type Flags 581** 582** When SQLite invokes the xSync() method of an 583** [sqlite3_io_methods] object it uses a combination of 584** these integer values as the second argument. 585** 586** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 587** sync operation only needs to flush data to mass storage. Inode 588** information need not be flushed. If the lower four bits of the flag 589** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 590** If the lower four bits equal SQLITE_SYNC_FULL, that means 591** to use Mac OS X style fullsync instead of fsync(). 592** 593** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 594** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 595** settings. The [synchronous pragma] determines when calls to the 596** xSync VFS method occur and applies uniformly across all platforms. 597** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 598** energetic or rigorous or forceful the sync operations are and 599** only make a difference on Mac OSX for the default SQLite code. 600** (Third-party VFS implementations might also make the distinction 601** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 602** operating systems natively supported by SQLite, only Mac OSX 603** cares about the difference.) 604*/ 605#define SQLITE_SYNC_NORMAL 0x00002 606#define SQLITE_SYNC_FULL 0x00003 607#define SQLITE_SYNC_DATAONLY 0x00010 608 609/* 610** CAPI3REF: OS Interface Open File Handle 611** 612** An [sqlite3_file] object represents an open file in the 613** [sqlite3_vfs | OS interface layer]. Individual OS interface 614** implementations will 615** want to subclass this object by appending additional fields 616** for their own use. The pMethods entry is a pointer to an 617** [sqlite3_io_methods] object that defines methods for performing 618** I/O operations on the open file. 619*/ 620typedef struct sqlite3_file sqlite3_file; 621struct sqlite3_file { 622 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 623}; 624 625/* 626** CAPI3REF: OS Interface File Virtual Methods Object 627** 628** Every file opened by the [sqlite3_vfs.xOpen] method populates an 629** [sqlite3_file] object (or, more commonly, a subclass of the 630** [sqlite3_file] object) with a pointer to an instance of this object. 631** This object defines the methods used to perform various operations 632** against the open file represented by the [sqlite3_file] object. 633** 634** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 635** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 636** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 637** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 638** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 639** to NULL. 640** 641** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 642** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 643** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 644** flag may be ORed in to indicate that only the data of the file 645** and not its inode needs to be synced. 646** 647** The integer values to xLock() and xUnlock() are one of 648** <ul> 649** <li> [SQLITE_LOCK_NONE], 650** <li> [SQLITE_LOCK_SHARED], 651** <li> [SQLITE_LOCK_RESERVED], 652** <li> [SQLITE_LOCK_PENDING], or 653** <li> [SQLITE_LOCK_EXCLUSIVE]. 654** </ul> 655** xLock() increases the lock. xUnlock() decreases the lock. 656** The xCheckReservedLock() method checks whether any database connection, 657** either in this process or in some other process, is holding a RESERVED, 658** PENDING, or EXCLUSIVE lock on the file. It returns true 659** if such a lock exists and false otherwise. 660** 661** The xFileControl() method is a generic interface that allows custom 662** VFS implementations to directly control an open file using the 663** [sqlite3_file_control()] interface. The second "op" argument is an 664** integer opcode. The third argument is a generic pointer intended to 665** point to a structure that may contain arguments or space in which to 666** write return values. Potential uses for xFileControl() might be 667** functions to enable blocking locks with timeouts, to change the 668** locking strategy (for example to use dot-file locks), to inquire 669** about the status of a lock, or to break stale locks. The SQLite 670** core reserves all opcodes less than 100 for its own use. 671** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 672** Applications that define a custom xFileControl method should use opcodes 673** greater than 100 to avoid conflicts. VFS implementations should 674** return [SQLITE_NOTFOUND] for file control opcodes that they do not 675** recognize. 676** 677** The xSectorSize() method returns the sector size of the 678** device that underlies the file. The sector size is the 679** minimum write that can be performed without disturbing 680** other bytes in the file. The xDeviceCharacteristics() 681** method returns a bit vector describing behaviors of the 682** underlying device: 683** 684** <ul> 685** <li> [SQLITE_IOCAP_ATOMIC] 686** <li> [SQLITE_IOCAP_ATOMIC512] 687** <li> [SQLITE_IOCAP_ATOMIC1K] 688** <li> [SQLITE_IOCAP_ATOMIC2K] 689** <li> [SQLITE_IOCAP_ATOMIC4K] 690** <li> [SQLITE_IOCAP_ATOMIC8K] 691** <li> [SQLITE_IOCAP_ATOMIC16K] 692** <li> [SQLITE_IOCAP_ATOMIC32K] 693** <li> [SQLITE_IOCAP_ATOMIC64K] 694** <li> [SQLITE_IOCAP_SAFE_APPEND] 695** <li> [SQLITE_IOCAP_SEQUENTIAL] 696** </ul> 697** 698** The SQLITE_IOCAP_ATOMIC property means that all writes of 699** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 700** mean that writes of blocks that are nnn bytes in size and 701** are aligned to an address which is an integer multiple of 702** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 703** that when data is appended to a file, the data is appended 704** first then the size of the file is extended, never the other 705** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 706** information is written to disk in the same order as calls 707** to xWrite(). 708** 709** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 710** in the unread portions of the buffer with zeros. A VFS that 711** fails to zero-fill short reads might seem to work. However, 712** failure to zero-fill short reads will eventually lead to 713** database corruption. 714*/ 715typedef struct sqlite3_io_methods sqlite3_io_methods; 716struct sqlite3_io_methods { 717 int iVersion; 718 int (*xClose)(sqlite3_file*); 719 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 720 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 721 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 722 int (*xSync)(sqlite3_file*, int flags); 723 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 724 int (*xLock)(sqlite3_file*, int); 725 int (*xUnlock)(sqlite3_file*, int); 726 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 727 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 728 int (*xSectorSize)(sqlite3_file*); 729 int (*xDeviceCharacteristics)(sqlite3_file*); 730 /* Methods above are valid for version 1 */ 731 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 732 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 733 void (*xShmBarrier)(sqlite3_file*); 734 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 735 /* Methods above are valid for version 2 */ 736 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 737 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 738 /* Methods above are valid for version 3 */ 739 /* Additional methods may be added in future releases */ 740}; 741 742/* 743** CAPI3REF: Standard File Control Opcodes 744** 745** These integer constants are opcodes for the xFileControl method 746** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 747** interface. 748** 749** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 750** opcode causes the xFileControl method to write the current state of 751** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 752** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 753** into an integer that the pArg argument points to. This capability 754** is used during testing and only needs to be supported when SQLITE_TEST 755** is defined. 756** <ul> 757** <li>[[SQLITE_FCNTL_SIZE_HINT]] 758** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 759** layer a hint of how large the database file will grow to be during the 760** current transaction. This hint is not guaranteed to be accurate but it 761** is often close. The underlying VFS might choose to preallocate database 762** file space based on this hint in order to help writes to the database 763** file run faster. 764** 765** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 766** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 767** extends and truncates the database file in chunks of a size specified 768** by the user. The fourth argument to [sqlite3_file_control()] should 769** point to an integer (type int) containing the new chunk-size to use 770** for the nominated database. Allocating database file space in large 771** chunks (say 1MB at a time), may reduce file-system fragmentation and 772** improve performance on some systems. 773** 774** <li>[[SQLITE_FCNTL_FILE_POINTER]] 775** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 776** to the [sqlite3_file] object associated with a particular database 777** connection. See the [sqlite3_file_control()] documentation for 778** additional information. 779** 780** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 781** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by 782** SQLite and sent to all VFSes in place of a call to the xSync method 783** when the database connection has [PRAGMA synchronous] set to OFF.)^ 784** Some specialized VFSes need this signal in order to operate correctly 785** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most 786** VFSes do not need this signal and should silently ignore this opcode. 787** Applications should not call [sqlite3_file_control()] with this 788** opcode as doing so may disrupt the operation of the specialized VFSes 789** that do require it. 790** 791** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 792** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 793** retry counts and intervals for certain disk I/O operations for the 794** windows [VFS] in order to provide robustness in the presence of 795** anti-virus programs. By default, the windows VFS will retry file read, 796** file write, and file delete operations up to 10 times, with a delay 797** of 25 milliseconds before the first retry and with the delay increasing 798** by an additional 25 milliseconds with each subsequent retry. This 799** opcode allows these two values (10 retries and 25 milliseconds of delay) 800** to be adjusted. The values are changed for all database connections 801** within the same process. The argument is a pointer to an array of two 802** integers where the first integer i the new retry count and the second 803** integer is the delay. If either integer is negative, then the setting 804** is not changed but instead the prior value of that setting is written 805** into the array entry, allowing the current retry settings to be 806** interrogated. The zDbName parameter is ignored. 807** 808** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 809** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 810** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 811** write ahead log and shared memory files used for transaction control 812** are automatically deleted when the latest connection to the database 813** closes. Setting persistent WAL mode causes those files to persist after 814** close. Persisting the files is useful when other processes that do not 815** have write permission on the directory containing the database file want 816** to read the database file, as the WAL and shared memory files must exist 817** in order for the database to be readable. The fourth parameter to 818** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 819** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 820** WAL mode. If the integer is -1, then it is overwritten with the current 821** WAL persistence setting. 822** 823** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 824** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 825** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 826** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 827** xDeviceCharacteristics methods. The fourth parameter to 828** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 829** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 830** mode. If the integer is -1, then it is overwritten with the current 831** zero-damage mode setting. 832** 833** <li>[[SQLITE_FCNTL_OVERWRITE]] 834** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 835** a write transaction to indicate that, unless it is rolled back for some 836** reason, the entire database file will be overwritten by the current 837** transaction. This is used by VACUUM operations. 838** 839** <li>[[SQLITE_FCNTL_VFSNAME]] 840** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 841** all [VFSes] in the VFS stack. The names are of all VFS shims and the 842** final bottom-level VFS are written into memory obtained from 843** [sqlite3_malloc()] and the result is stored in the char* variable 844** that the fourth parameter of [sqlite3_file_control()] points to. 845** The caller is responsible for freeing the memory when done. As with 846** all file-control actions, there is no guarantee that this will actually 847** do anything. Callers should initialize the char* variable to a NULL 848** pointer in case this file-control is not implemented. This file-control 849** is intended for diagnostic use only. 850** 851** <li>[[SQLITE_FCNTL_PRAGMA]] 852** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 853** file control is sent to the open [sqlite3_file] object corresponding 854** to the database file to which the pragma statement refers. ^The argument 855** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 856** pointers to strings (char**) in which the second element of the array 857** is the name of the pragma and the third element is the argument to the 858** pragma or NULL if the pragma has no argument. ^The handler for an 859** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 860** of the char** argument point to a string obtained from [sqlite3_mprintf()] 861** or the equivalent and that string will become the result of the pragma or 862** the error message if the pragma fails. ^If the 863** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 864** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 865** file control returns [SQLITE_OK], then the parser assumes that the 866** VFS has handled the PRAGMA itself and the parser generates a no-op 867** prepared statement. ^If the [SQLITE_FCNTL_PRAGMA] file control returns 868** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 869** that the VFS encountered an error while handling the [PRAGMA] and the 870** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 871** file control occurs at the beginning of pragma statement analysis and so 872** it is able to override built-in [PRAGMA] statements. 873** 874** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 875** ^The [SQLITE_FCNTL_BUSYHANDLER] 876** file-control may be invoked by SQLite on the database file handle 877** shortly after it is opened in order to provide a custom VFS with access 878** to the connections busy-handler callback. The argument is of type (void **) 879** - an array of two (void *) values. The first (void *) actually points 880** to a function of type (int (*)(void *)). In order to invoke the connections 881** busy-handler, this function should be invoked with the second (void *) in 882** the array as the only argument. If it returns non-zero, then the operation 883** should be retried. If it returns zero, the custom VFS should abandon the 884** current operation. 885** 886** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 887** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 888** to have SQLite generate a 889** temporary filename using the same algorithm that is followed to generate 890** temporary filenames for TEMP tables and other internal uses. The 891** argument should be a char** which will be filled with the filename 892** written into memory obtained from [sqlite3_malloc()]. The caller should 893** invoke [sqlite3_free()] on the result to avoid a memory leak. 894** 895** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 896** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 897** maximum number of bytes that will be used for memory-mapped I/O. 898** The argument is a pointer to a value of type sqlite3_int64 that 899** is an advisory maximum number of bytes in the file to memory map. The 900** pointer is overwritten with the old value. The limit is not changed if 901** the value originally pointed to is negative, and so the current limit 902** can be queried by passing in a pointer to a negative number. This 903** file-control is used internally to implement [PRAGMA mmap_size]. 904** 905** </ul> 906*/ 907#define SQLITE_FCNTL_LOCKSTATE 1 908#define SQLITE_GET_LOCKPROXYFILE 2 909#define SQLITE_SET_LOCKPROXYFILE 3 910#define SQLITE_LAST_ERRNO 4 911#define SQLITE_FCNTL_SIZE_HINT 5 912#define SQLITE_FCNTL_CHUNK_SIZE 6 913#define SQLITE_FCNTL_FILE_POINTER 7 914#define SQLITE_FCNTL_SYNC_OMITTED 8 915#define SQLITE_FCNTL_WIN32_AV_RETRY 9 916#define SQLITE_FCNTL_PERSIST_WAL 10 917#define SQLITE_FCNTL_OVERWRITE 11 918#define SQLITE_FCNTL_VFSNAME 12 919#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 920#define SQLITE_FCNTL_PRAGMA 14 921#define SQLITE_FCNTL_BUSYHANDLER 15 922#define SQLITE_FCNTL_TEMPFILENAME 16 923#define SQLITE_FCNTL_MMAP_SIZE 18 924 925/* 926** CAPI3REF: Mutex Handle 927** 928** The mutex module within SQLite defines [sqlite3_mutex] to be an 929** abstract type for a mutex object. The SQLite core never looks 930** at the internal representation of an [sqlite3_mutex]. It only 931** deals with pointers to the [sqlite3_mutex] object. 932** 933** Mutexes are created using [sqlite3_mutex_alloc()]. 934*/ 935typedef struct sqlite3_mutex sqlite3_mutex; 936 937/* 938** CAPI3REF: OS Interface Object 939** 940** An instance of the sqlite3_vfs object defines the interface between 941** the SQLite core and the underlying operating system. The "vfs" 942** in the name of the object stands for "virtual file system". See 943** the [VFS | VFS documentation] for further information. 944** 945** The value of the iVersion field is initially 1 but may be larger in 946** future versions of SQLite. Additional fields may be appended to this 947** object when the iVersion value is increased. Note that the structure 948** of the sqlite3_vfs object changes in the transaction between 949** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 950** modified. 951** 952** The szOsFile field is the size of the subclassed [sqlite3_file] 953** structure used by this VFS. mxPathname is the maximum length of 954** a pathname in this VFS. 955** 956** Registered sqlite3_vfs objects are kept on a linked list formed by 957** the pNext pointer. The [sqlite3_vfs_register()] 958** and [sqlite3_vfs_unregister()] interfaces manage this list 959** in a thread-safe way. The [sqlite3_vfs_find()] interface 960** searches the list. Neither the application code nor the VFS 961** implementation should use the pNext pointer. 962** 963** The pNext field is the only field in the sqlite3_vfs 964** structure that SQLite will ever modify. SQLite will only access 965** or modify this field while holding a particular static mutex. 966** The application should never modify anything within the sqlite3_vfs 967** object once the object has been registered. 968** 969** The zName field holds the name of the VFS module. The name must 970** be unique across all VFS modules. 971** 972** [[sqlite3_vfs.xOpen]] 973** ^SQLite guarantees that the zFilename parameter to xOpen 974** is either a NULL pointer or string obtained 975** from xFullPathname() with an optional suffix added. 976** ^If a suffix is added to the zFilename parameter, it will 977** consist of a single "-" character followed by no more than 978** 11 alphanumeric and/or "-" characters. 979** ^SQLite further guarantees that 980** the string will be valid and unchanged until xClose() is 981** called. Because of the previous sentence, 982** the [sqlite3_file] can safely store a pointer to the 983** filename if it needs to remember the filename for some reason. 984** If the zFilename parameter to xOpen is a NULL pointer then xOpen 985** must invent its own temporary name for the file. ^Whenever the 986** xFilename parameter is NULL it will also be the case that the 987** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 988** 989** The flags argument to xOpen() includes all bits set in 990** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 991** or [sqlite3_open16()] is used, then flags includes at least 992** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 993** If xOpen() opens a file read-only then it sets *pOutFlags to 994** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 995** 996** ^(SQLite will also add one of the following flags to the xOpen() 997** call, depending on the object being opened: 998** 999** <ul> 1000** <li> [SQLITE_OPEN_MAIN_DB] 1001** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1002** <li> [SQLITE_OPEN_TEMP_DB] 1003** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1004** <li> [SQLITE_OPEN_TRANSIENT_DB] 1005** <li> [SQLITE_OPEN_SUBJOURNAL] 1006** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1007** <li> [SQLITE_OPEN_WAL] 1008** </ul>)^ 1009** 1010** The file I/O implementation can use the object type flags to 1011** change the way it deals with files. For example, an application 1012** that does not care about crash recovery or rollback might make 1013** the open of a journal file a no-op. Writes to this journal would 1014** also be no-ops, and any attempt to read the journal would return 1015** SQLITE_IOERR. Or the implementation might recognize that a database 1016** file will be doing page-aligned sector reads and writes in a random 1017** order and set up its I/O subsystem accordingly. 1018** 1019** SQLite might also add one of the following flags to the xOpen method: 1020** 1021** <ul> 1022** <li> [SQLITE_OPEN_DELETEONCLOSE] 1023** <li> [SQLITE_OPEN_EXCLUSIVE] 1024** </ul> 1025** 1026** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1027** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1028** will be set for TEMP databases and their journals, transient 1029** databases, and subjournals. 1030** 1031** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1032** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1033** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1034** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1035** SQLITE_OPEN_CREATE, is used to indicate that file should always 1036** be created, and that it is an error if it already exists. 1037** It is <i>not</i> used to indicate the file should be opened 1038** for exclusive access. 1039** 1040** ^At least szOsFile bytes of memory are allocated by SQLite 1041** to hold the [sqlite3_file] structure passed as the third 1042** argument to xOpen. The xOpen method does not have to 1043** allocate the structure; it should just fill it in. Note that 1044** the xOpen method must set the sqlite3_file.pMethods to either 1045** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1046** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1047** element will be valid after xOpen returns regardless of the success 1048** or failure of the xOpen call. 1049** 1050** [[sqlite3_vfs.xAccess]] 1051** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1052** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1053** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1054** to test whether a file is at least readable. The file can be a 1055** directory. 1056** 1057** ^SQLite will always allocate at least mxPathname+1 bytes for the 1058** output buffer xFullPathname. The exact size of the output buffer 1059** is also passed as a parameter to both methods. If the output buffer 1060** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1061** handled as a fatal error by SQLite, vfs implementations should endeavor 1062** to prevent this by setting mxPathname to a sufficiently large value. 1063** 1064** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1065** interfaces are not strictly a part of the filesystem, but they are 1066** included in the VFS structure for completeness. 1067** The xRandomness() function attempts to return nBytes bytes 1068** of good-quality randomness into zOut. The return value is 1069** the actual number of bytes of randomness obtained. 1070** The xSleep() method causes the calling thread to sleep for at 1071** least the number of microseconds given. ^The xCurrentTime() 1072** method returns a Julian Day Number for the current date and time as 1073** a floating point value. 1074** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1075** Day Number multiplied by 86400000 (the number of milliseconds in 1076** a 24-hour day). 1077** ^SQLite will use the xCurrentTimeInt64() method to get the current 1078** date and time if that method is available (if iVersion is 2 or 1079** greater and the function pointer is not NULL) and will fall back 1080** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1081** 1082** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1083** are not used by the SQLite core. These optional interfaces are provided 1084** by some VFSes to facilitate testing of the VFS code. By overriding 1085** system calls with functions under its control, a test program can 1086** simulate faults and error conditions that would otherwise be difficult 1087** or impossible to induce. The set of system calls that can be overridden 1088** varies from one VFS to another, and from one version of the same VFS to the 1089** next. Applications that use these interfaces must be prepared for any 1090** or all of these interfaces to be NULL or for their behavior to change 1091** from one release to the next. Applications must not attempt to access 1092** any of these methods if the iVersion of the VFS is less than 3. 1093*/ 1094typedef struct sqlite3_vfs sqlite3_vfs; 1095typedef void (*sqlite3_syscall_ptr)(void); 1096struct sqlite3_vfs { 1097 int iVersion; /* Structure version number (currently 3) */ 1098 int szOsFile; /* Size of subclassed sqlite3_file */ 1099 int mxPathname; /* Maximum file pathname length */ 1100 sqlite3_vfs *pNext; /* Next registered VFS */ 1101 const char *zName; /* Name of this virtual file system */ 1102 void *pAppData; /* Pointer to application-specific data */ 1103 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1104 int flags, int *pOutFlags); 1105 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1106 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1107 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1108 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1109 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1110 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1111 void (*xDlClose)(sqlite3_vfs*, void*); 1112 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1113 int (*xSleep)(sqlite3_vfs*, int microseconds); 1114 int (*xCurrentTime)(sqlite3_vfs*, double*); 1115 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1116 /* 1117 ** The methods above are in version 1 of the sqlite_vfs object 1118 ** definition. Those that follow are added in version 2 or later 1119 */ 1120 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1121 /* 1122 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1123 ** Those below are for version 3 and greater. 1124 */ 1125 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1126 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1127 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1128 /* 1129 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1130 ** New fields may be appended in figure versions. The iVersion 1131 ** value will increment whenever this happens. 1132 */ 1133}; 1134 1135/* 1136** CAPI3REF: Flags for the xAccess VFS method 1137** 1138** These integer constants can be used as the third parameter to 1139** the xAccess method of an [sqlite3_vfs] object. They determine 1140** what kind of permissions the xAccess method is looking for. 1141** With SQLITE_ACCESS_EXISTS, the xAccess method 1142** simply checks whether the file exists. 1143** With SQLITE_ACCESS_READWRITE, the xAccess method 1144** checks whether the named directory is both readable and writable 1145** (in other words, if files can be added, removed, and renamed within 1146** the directory). 1147** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1148** [temp_store_directory pragma], though this could change in a future 1149** release of SQLite. 1150** With SQLITE_ACCESS_READ, the xAccess method 1151** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1152** currently unused, though it might be used in a future release of 1153** SQLite. 1154*/ 1155#define SQLITE_ACCESS_EXISTS 0 1156#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1157#define SQLITE_ACCESS_READ 2 /* Unused */ 1158 1159/* 1160** CAPI3REF: Flags for the xShmLock VFS method 1161** 1162** These integer constants define the various locking operations 1163** allowed by the xShmLock method of [sqlite3_io_methods]. The 1164** following are the only legal combinations of flags to the 1165** xShmLock method: 1166** 1167** <ul> 1168** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1169** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1170** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1171** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1172** </ul> 1173** 1174** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1175** was given no the corresponding lock. 1176** 1177** The xShmLock method can transition between unlocked and SHARED or 1178** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1179** and EXCLUSIVE. 1180*/ 1181#define SQLITE_SHM_UNLOCK 1 1182#define SQLITE_SHM_LOCK 2 1183#define SQLITE_SHM_SHARED 4 1184#define SQLITE_SHM_EXCLUSIVE 8 1185 1186/* 1187** CAPI3REF: Maximum xShmLock index 1188** 1189** The xShmLock method on [sqlite3_io_methods] may use values 1190** between 0 and this upper bound as its "offset" argument. 1191** The SQLite core will never attempt to acquire or release a 1192** lock outside of this range 1193*/ 1194#define SQLITE_SHM_NLOCK 8 1195 1196 1197/* 1198** CAPI3REF: Initialize The SQLite Library 1199** 1200** ^The sqlite3_initialize() routine initializes the 1201** SQLite library. ^The sqlite3_shutdown() routine 1202** deallocates any resources that were allocated by sqlite3_initialize(). 1203** These routines are designed to aid in process initialization and 1204** shutdown on embedded systems. Workstation applications using 1205** SQLite normally do not need to invoke either of these routines. 1206** 1207** A call to sqlite3_initialize() is an "effective" call if it is 1208** the first time sqlite3_initialize() is invoked during the lifetime of 1209** the process, or if it is the first time sqlite3_initialize() is invoked 1210** following a call to sqlite3_shutdown(). ^(Only an effective call 1211** of sqlite3_initialize() does any initialization. All other calls 1212** are harmless no-ops.)^ 1213** 1214** A call to sqlite3_shutdown() is an "effective" call if it is the first 1215** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1216** an effective call to sqlite3_shutdown() does any deinitialization. 1217** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1218** 1219** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1220** is not. The sqlite3_shutdown() interface must only be called from a 1221** single thread. All open [database connections] must be closed and all 1222** other SQLite resources must be deallocated prior to invoking 1223** sqlite3_shutdown(). 1224** 1225** Among other things, ^sqlite3_initialize() will invoke 1226** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1227** will invoke sqlite3_os_end(). 1228** 1229** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1230** ^If for some reason, sqlite3_initialize() is unable to initialize 1231** the library (perhaps it is unable to allocate a needed resource such 1232** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1233** 1234** ^The sqlite3_initialize() routine is called internally by many other 1235** SQLite interfaces so that an application usually does not need to 1236** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1237** calls sqlite3_initialize() so the SQLite library will be automatically 1238** initialized when [sqlite3_open()] is called if it has not be initialized 1239** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1240** compile-time option, then the automatic calls to sqlite3_initialize() 1241** are omitted and the application must call sqlite3_initialize() directly 1242** prior to using any other SQLite interface. For maximum portability, 1243** it is recommended that applications always invoke sqlite3_initialize() 1244** directly prior to using any other SQLite interface. Future releases 1245** of SQLite may require this. In other words, the behavior exhibited 1246** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1247** default behavior in some future release of SQLite. 1248** 1249** The sqlite3_os_init() routine does operating-system specific 1250** initialization of the SQLite library. The sqlite3_os_end() 1251** routine undoes the effect of sqlite3_os_init(). Typical tasks 1252** performed by these routines include allocation or deallocation 1253** of static resources, initialization of global variables, 1254** setting up a default [sqlite3_vfs] module, or setting up 1255** a default configuration using [sqlite3_config()]. 1256** 1257** The application should never invoke either sqlite3_os_init() 1258** or sqlite3_os_end() directly. The application should only invoke 1259** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1260** interface is called automatically by sqlite3_initialize() and 1261** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1262** implementations for sqlite3_os_init() and sqlite3_os_end() 1263** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1264** When [custom builds | built for other platforms] 1265** (using the [SQLITE_OS_OTHER=1] compile-time 1266** option) the application must supply a suitable implementation for 1267** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1268** implementation of sqlite3_os_init() or sqlite3_os_end() 1269** must return [SQLITE_OK] on success and some other [error code] upon 1270** failure. 1271*/ 1272int sqlite3_initialize(void); 1273int sqlite3_shutdown(void); 1274int sqlite3_os_init(void); 1275int sqlite3_os_end(void); 1276 1277/* 1278** CAPI3REF: Configuring The SQLite Library 1279** 1280** The sqlite3_config() interface is used to make global configuration 1281** changes to SQLite in order to tune SQLite to the specific needs of 1282** the application. The default configuration is recommended for most 1283** applications and so this routine is usually not necessary. It is 1284** provided to support rare applications with unusual needs. 1285** 1286** The sqlite3_config() interface is not threadsafe. The application 1287** must insure that no other SQLite interfaces are invoked by other 1288** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1289** may only be invoked prior to library initialization using 1290** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1291** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1292** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1293** Note, however, that ^sqlite3_config() can be called as part of the 1294** implementation of an application-defined [sqlite3_os_init()]. 1295** 1296** The first argument to sqlite3_config() is an integer 1297** [configuration option] that determines 1298** what property of SQLite is to be configured. Subsequent arguments 1299** vary depending on the [configuration option] 1300** in the first argument. 1301** 1302** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1303** ^If the option is unknown or SQLite is unable to set the option 1304** then this routine returns a non-zero [error code]. 1305*/ 1306int sqlite3_config(int, ...); 1307 1308/* 1309** CAPI3REF: Configure database connections 1310** 1311** The sqlite3_db_config() interface is used to make configuration 1312** changes to a [database connection]. The interface is similar to 1313** [sqlite3_config()] except that the changes apply to a single 1314** [database connection] (specified in the first argument). 1315** 1316** The second argument to sqlite3_db_config(D,V,...) is the 1317** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1318** that indicates what aspect of the [database connection] is being configured. 1319** Subsequent arguments vary depending on the configuration verb. 1320** 1321** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1322** the call is considered successful. 1323*/ 1324int sqlite3_db_config(sqlite3*, int op, ...); 1325 1326/* 1327** CAPI3REF: Memory Allocation Routines 1328** 1329** An instance of this object defines the interface between SQLite 1330** and low-level memory allocation routines. 1331** 1332** This object is used in only one place in the SQLite interface. 1333** A pointer to an instance of this object is the argument to 1334** [sqlite3_config()] when the configuration option is 1335** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1336** By creating an instance of this object 1337** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1338** during configuration, an application can specify an alternative 1339** memory allocation subsystem for SQLite to use for all of its 1340** dynamic memory needs. 1341** 1342** Note that SQLite comes with several [built-in memory allocators] 1343** that are perfectly adequate for the overwhelming majority of applications 1344** and that this object is only useful to a tiny minority of applications 1345** with specialized memory allocation requirements. This object is 1346** also used during testing of SQLite in order to specify an alternative 1347** memory allocator that simulates memory out-of-memory conditions in 1348** order to verify that SQLite recovers gracefully from such 1349** conditions. 1350** 1351** The xMalloc, xRealloc, and xFree methods must work like the 1352** malloc(), realloc() and free() functions from the standard C library. 1353** ^SQLite guarantees that the second argument to 1354** xRealloc is always a value returned by a prior call to xRoundup. 1355** 1356** xSize should return the allocated size of a memory allocation 1357** previously obtained from xMalloc or xRealloc. The allocated size 1358** is always at least as big as the requested size but may be larger. 1359** 1360** The xRoundup method returns what would be the allocated size of 1361** a memory allocation given a particular requested size. Most memory 1362** allocators round up memory allocations at least to the next multiple 1363** of 8. Some allocators round up to a larger multiple or to a power of 2. 1364** Every memory allocation request coming in through [sqlite3_malloc()] 1365** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1366** that causes the corresponding memory allocation to fail. 1367** 1368** The xInit method initializes the memory allocator. (For example, 1369** it might allocate any require mutexes or initialize internal data 1370** structures. The xShutdown method is invoked (indirectly) by 1371** [sqlite3_shutdown()] and should deallocate any resources acquired 1372** by xInit. The pAppData pointer is used as the only parameter to 1373** xInit and xShutdown. 1374** 1375** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1376** the xInit method, so the xInit method need not be threadsafe. The 1377** xShutdown method is only called from [sqlite3_shutdown()] so it does 1378** not need to be threadsafe either. For all other methods, SQLite 1379** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1380** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1381** it is by default) and so the methods are automatically serialized. 1382** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1383** methods must be threadsafe or else make their own arrangements for 1384** serialization. 1385** 1386** SQLite will never invoke xInit() more than once without an intervening 1387** call to xShutdown(). 1388*/ 1389typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1390struct sqlite3_mem_methods { 1391 void *(*xMalloc)(int); /* Memory allocation function */ 1392 void (*xFree)(void*); /* Free a prior allocation */ 1393 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1394 int (*xSize)(void*); /* Return the size of an allocation */ 1395 int (*xRoundup)(int); /* Round up request size to allocation size */ 1396 int (*xInit)(void*); /* Initialize the memory allocator */ 1397 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1398 void *pAppData; /* Argument to xInit() and xShutdown() */ 1399}; 1400 1401/* 1402** CAPI3REF: Configuration Options 1403** KEYWORDS: {configuration option} 1404** 1405** These constants are the available integer configuration options that 1406** can be passed as the first argument to the [sqlite3_config()] interface. 1407** 1408** New configuration options may be added in future releases of SQLite. 1409** Existing configuration options might be discontinued. Applications 1410** should check the return code from [sqlite3_config()] to make sure that 1411** the call worked. The [sqlite3_config()] interface will return a 1412** non-zero [error code] if a discontinued or unsupported configuration option 1413** is invoked. 1414** 1415** <dl> 1416** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1417** <dd>There are no arguments to this option. ^This option sets the 1418** [threading mode] to Single-thread. In other words, it disables 1419** all mutexing and puts SQLite into a mode where it can only be used 1420** by a single thread. ^If SQLite is compiled with 1421** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1422** it is not possible to change the [threading mode] from its default 1423** value of Single-thread and so [sqlite3_config()] will return 1424** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1425** configuration option.</dd> 1426** 1427** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1428** <dd>There are no arguments to this option. ^This option sets the 1429** [threading mode] to Multi-thread. In other words, it disables 1430** mutexing on [database connection] and [prepared statement] objects. 1431** The application is responsible for serializing access to 1432** [database connections] and [prepared statements]. But other mutexes 1433** are enabled so that SQLite will be safe to use in a multi-threaded 1434** environment as long as no two threads attempt to use the same 1435** [database connection] at the same time. ^If SQLite is compiled with 1436** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1437** it is not possible to set the Multi-thread [threading mode] and 1438** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1439** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1440** 1441** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1442** <dd>There are no arguments to this option. ^This option sets the 1443** [threading mode] to Serialized. In other words, this option enables 1444** all mutexes including the recursive 1445** mutexes on [database connection] and [prepared statement] objects. 1446** In this mode (which is the default when SQLite is compiled with 1447** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1448** to [database connections] and [prepared statements] so that the 1449** application is free to use the same [database connection] or the 1450** same [prepared statement] in different threads at the same time. 1451** ^If SQLite is compiled with 1452** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1453** it is not possible to set the Serialized [threading mode] and 1454** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1455** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1456** 1457** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1458** <dd> ^(This option takes a single argument which is a pointer to an 1459** instance of the [sqlite3_mem_methods] structure. The argument specifies 1460** alternative low-level memory allocation routines to be used in place of 1461** the memory allocation routines built into SQLite.)^ ^SQLite makes 1462** its own private copy of the content of the [sqlite3_mem_methods] structure 1463** before the [sqlite3_config()] call returns.</dd> 1464** 1465** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1466** <dd> ^(This option takes a single argument which is a pointer to an 1467** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1468** structure is filled with the currently defined memory allocation routines.)^ 1469** This option can be used to overload the default memory allocation 1470** routines with a wrapper that simulations memory allocation failure or 1471** tracks memory usage, for example. </dd> 1472** 1473** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1474** <dd> ^This option takes single argument of type int, interpreted as a 1475** boolean, which enables or disables the collection of memory allocation 1476** statistics. ^(When memory allocation statistics are disabled, the 1477** following SQLite interfaces become non-operational: 1478** <ul> 1479** <li> [sqlite3_memory_used()] 1480** <li> [sqlite3_memory_highwater()] 1481** <li> [sqlite3_soft_heap_limit64()] 1482** <li> [sqlite3_status()] 1483** </ul>)^ 1484** ^Memory allocation statistics are enabled by default unless SQLite is 1485** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1486** allocation statistics are disabled by default. 1487** </dd> 1488** 1489** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1490** <dd> ^This option specifies a static memory buffer that SQLite can use for 1491** scratch memory. There are three arguments: A pointer an 8-byte 1492** aligned memory buffer from which the scratch allocations will be 1493** drawn, the size of each scratch allocation (sz), 1494** and the maximum number of scratch allocations (N). The sz 1495** argument must be a multiple of 16. 1496** The first argument must be a pointer to an 8-byte aligned buffer 1497** of at least sz*N bytes of memory. 1498** ^SQLite will use no more than two scratch buffers per thread. So 1499** N should be set to twice the expected maximum number of threads. 1500** ^SQLite will never require a scratch buffer that is more than 6 1501** times the database page size. ^If SQLite needs needs additional 1502** scratch memory beyond what is provided by this configuration option, then 1503** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1504** 1505** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1506** <dd> ^This option specifies a static memory buffer that SQLite can use for 1507** the database page cache with the default page cache implementation. 1508** This configuration should not be used if an application-define page 1509** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option. 1510** There are three arguments to this option: A pointer to 8-byte aligned 1511** memory, the size of each page buffer (sz), and the number of pages (N). 1512** The sz argument should be the size of the largest database page 1513** (a power of two between 512 and 32768) plus a little extra for each 1514** page header. ^The page header size is 20 to 40 bytes depending on 1515** the host architecture. ^It is harmless, apart from the wasted memory, 1516** to make sz a little too large. The first 1517** argument should point to an allocation of at least sz*N bytes of memory. 1518** ^SQLite will use the memory provided by the first argument to satisfy its 1519** memory needs for the first N pages that it adds to cache. ^If additional 1520** page cache memory is needed beyond what is provided by this option, then 1521** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1522** The pointer in the first argument must 1523** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1524** will be undefined.</dd> 1525** 1526** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1527** <dd> ^This option specifies a static memory buffer that SQLite will use 1528** for all of its dynamic memory allocation needs beyond those provided 1529** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1530** There are three arguments: An 8-byte aligned pointer to the memory, 1531** the number of bytes in the memory buffer, and the minimum allocation size. 1532** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1533** to using its default memory allocator (the system malloc() implementation), 1534** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1535** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1536** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1537** allocator is engaged to handle all of SQLites memory allocation needs. 1538** The first pointer (the memory pointer) must be aligned to an 8-byte 1539** boundary or subsequent behavior of SQLite will be undefined. 1540** The minimum allocation size is capped at 2**12. Reasonable values 1541** for the minimum allocation size are 2**5 through 2**8.</dd> 1542** 1543** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1544** <dd> ^(This option takes a single argument which is a pointer to an 1545** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1546** alternative low-level mutex routines to be used in place 1547** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1548** content of the [sqlite3_mutex_methods] structure before the call to 1549** [sqlite3_config()] returns. ^If SQLite is compiled with 1550** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1551** the entire mutexing subsystem is omitted from the build and hence calls to 1552** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1553** return [SQLITE_ERROR].</dd> 1554** 1555** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1556** <dd> ^(This option takes a single argument which is a pointer to an 1557** instance of the [sqlite3_mutex_methods] structure. The 1558** [sqlite3_mutex_methods] 1559** structure is filled with the currently defined mutex routines.)^ 1560** This option can be used to overload the default mutex allocation 1561** routines with a wrapper used to track mutex usage for performance 1562** profiling or testing, for example. ^If SQLite is compiled with 1563** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1564** the entire mutexing subsystem is omitted from the build and hence calls to 1565** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1566** return [SQLITE_ERROR].</dd> 1567** 1568** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1569** <dd> ^(This option takes two arguments that determine the default 1570** memory allocation for the lookaside memory allocator on each 1571** [database connection]. The first argument is the 1572** size of each lookaside buffer slot and the second is the number of 1573** slots allocated to each database connection.)^ ^(This option sets the 1574** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1575** verb to [sqlite3_db_config()] can be used to change the lookaside 1576** configuration on individual connections.)^ </dd> 1577** 1578** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1579** <dd> ^(This option takes a single argument which is a pointer to 1580** an [sqlite3_pcache_methods2] object. This object specifies the interface 1581** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1582** object and uses it for page cache memory allocations.</dd> 1583** 1584** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1585** <dd> ^(This option takes a single argument which is a pointer to an 1586** [sqlite3_pcache_methods2] object. SQLite copies of the current 1587** page cache implementation into that object.)^ </dd> 1588** 1589** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1590** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1591** global [error log]. 1592** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1593** function with a call signature of void(*)(void*,int,const char*), 1594** and a pointer to void. ^If the function pointer is not NULL, it is 1595** invoked by [sqlite3_log()] to process each logging event. ^If the 1596** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1597** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1598** passed through as the first parameter to the application-defined logger 1599** function whenever that function is invoked. ^The second parameter to 1600** the logger function is a copy of the first parameter to the corresponding 1601** [sqlite3_log()] call and is intended to be a [result code] or an 1602** [extended result code]. ^The third parameter passed to the logger is 1603** log message after formatting via [sqlite3_snprintf()]. 1604** The SQLite logging interface is not reentrant; the logger function 1605** supplied by the application must not invoke any SQLite interface. 1606** In a multi-threaded application, the application-defined logger 1607** function must be threadsafe. </dd> 1608** 1609** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1610** <dd> This option takes a single argument of type int. If non-zero, then 1611** URI handling is globally enabled. If the parameter is zero, then URI handling 1612** is globally disabled. If URI handling is globally enabled, all filenames 1613** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or 1614** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1615** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1616** connection is opened. If it is globally disabled, filenames are 1617** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1618** database connection is opened. By default, URI handling is globally 1619** disabled. The default value may be changed by compiling with the 1620** [SQLITE_USE_URI] symbol defined. 1621** 1622** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1623** <dd> This option takes a single integer argument which is interpreted as 1624** a boolean in order to enable or disable the use of covering indices for 1625** full table scans in the query optimizer. The default setting is determined 1626** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1627** if that compile-time option is omitted. 1628** The ability to disable the use of covering indices for full table scans 1629** is because some incorrectly coded legacy applications might malfunction 1630** malfunction when the optimization is enabled. Providing the ability to 1631** disable the optimization allows the older, buggy application code to work 1632** without change even with newer versions of SQLite. 1633** 1634** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1635** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1636** <dd> These options are obsolete and should not be used by new code. 1637** They are retained for backwards compatibility but are now no-ops. 1638** </dd> 1639** 1640** [[SQLITE_CONFIG_SQLLOG]] 1641** <dt>SQLITE_CONFIG_SQLLOG 1642** <dd>This option is only available if sqlite is compiled with the 1643** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1644** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1645** The second should be of type (void*). The callback is invoked by the library 1646** in three separate circumstances, identified by the value passed as the 1647** fourth parameter. If the fourth parameter is 0, then the database connection 1648** passed as the second argument has just been opened. The third argument 1649** points to a buffer containing the name of the main database file. If the 1650** fourth parameter is 1, then the SQL statement that the third parameter 1651** points to has just been executed. Or, if the fourth parameter is 2, then 1652** the connection being passed as the second parameter is being closed. The 1653** third parameter is passed NULL In this case. An example of using this 1654** configuration option can be seen in the "test_sqllog.c" source file in 1655** the canonical SQLite source tree.</dd> 1656** 1657** [[SQLITE_CONFIG_MMAP_SIZE]] 1658** <dt>SQLITE_CONFIG_MMAP_SIZE 1659** <dd>SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1660** that are the default mmap size limit (the default setting for 1661** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1662** The default setting can be overridden by each database connection using 1663** either the [PRAGMA mmap_size] command, or by using the 1664** [SQLITE_FCNTL_MMAP_SIZE] file control. The maximum allowed mmap size 1665** cannot be changed at run-time. Nor may the maximum allowed mmap size 1666** exceed the compile-time maximum mmap size set by the 1667** [SQLITE_MAX_MMAP_SIZE] compile-time option. 1668** If either argument to this option is negative, then that argument is 1669** changed to its compile-time default. 1670** </dl> 1671*/ 1672#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1673#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1674#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1675#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1676#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1677#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1678#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1679#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1680#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1681#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1682#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1683/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1684#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1685#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1686#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1687#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1688#define SQLITE_CONFIG_URI 17 /* int */ 1689#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1690#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1691#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1692#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1693#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1694 1695/* 1696** CAPI3REF: Database Connection Configuration Options 1697** 1698** These constants are the available integer configuration options that 1699** can be passed as the second argument to the [sqlite3_db_config()] interface. 1700** 1701** New configuration options may be added in future releases of SQLite. 1702** Existing configuration options might be discontinued. Applications 1703** should check the return code from [sqlite3_db_config()] to make sure that 1704** the call worked. ^The [sqlite3_db_config()] interface will return a 1705** non-zero [error code] if a discontinued or unsupported configuration option 1706** is invoked. 1707** 1708** <dl> 1709** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1710** <dd> ^This option takes three additional arguments that determine the 1711** [lookaside memory allocator] configuration for the [database connection]. 1712** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1713** pointer to a memory buffer to use for lookaside memory. 1714** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1715** may be NULL in which case SQLite will allocate the 1716** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1717** size of each lookaside buffer slot. ^The third argument is the number of 1718** slots. The size of the buffer in the first argument must be greater than 1719** or equal to the product of the second and third arguments. The buffer 1720** must be aligned to an 8-byte boundary. ^If the second argument to 1721** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1722** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1723** configuration for a database connection can only be changed when that 1724** connection is not currently using lookaside memory, or in other words 1725** when the "current value" returned by 1726** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1727** Any attempt to change the lookaside memory configuration when lookaside 1728** memory is in use leaves the configuration unchanged and returns 1729** [SQLITE_BUSY].)^</dd> 1730** 1731** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1732** <dd> ^This option is used to enable or disable the enforcement of 1733** [foreign key constraints]. There should be two additional arguments. 1734** The first argument is an integer which is 0 to disable FK enforcement, 1735** positive to enable FK enforcement or negative to leave FK enforcement 1736** unchanged. The second parameter is a pointer to an integer into which 1737** is written 0 or 1 to indicate whether FK enforcement is off or on 1738** following this call. The second parameter may be a NULL pointer, in 1739** which case the FK enforcement setting is not reported back. </dd> 1740** 1741** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1742** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1743** There should be two additional arguments. 1744** The first argument is an integer which is 0 to disable triggers, 1745** positive to enable triggers or negative to leave the setting unchanged. 1746** The second parameter is a pointer to an integer into which 1747** is written 0 or 1 to indicate whether triggers are disabled or enabled 1748** following this call. The second parameter may be a NULL pointer, in 1749** which case the trigger setting is not reported back. </dd> 1750** 1751** </dl> 1752*/ 1753#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1754#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1755#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1756 1757 1758/* 1759** CAPI3REF: Enable Or Disable Extended Result Codes 1760** 1761** ^The sqlite3_extended_result_codes() routine enables or disables the 1762** [extended result codes] feature of SQLite. ^The extended result 1763** codes are disabled by default for historical compatibility. 1764*/ 1765int sqlite3_extended_result_codes(sqlite3*, int onoff); 1766 1767/* 1768** CAPI3REF: Last Insert Rowid 1769** 1770** ^Each entry in an SQLite table has a unique 64-bit signed 1771** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1772** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1773** names are not also used by explicitly declared columns. ^If 1774** the table has a column of type [INTEGER PRIMARY KEY] then that column 1775** is another alias for the rowid. 1776** 1777** ^This routine returns the [rowid] of the most recent 1778** successful [INSERT] into the database from the [database connection] 1779** in the first argument. ^As of SQLite version 3.7.7, this routines 1780** records the last insert rowid of both ordinary tables and [virtual tables]. 1781** ^If no successful [INSERT]s 1782** have ever occurred on that database connection, zero is returned. 1783** 1784** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1785** method, then this routine will return the [rowid] of the inserted 1786** row as long as the trigger or virtual table method is running. 1787** But once the trigger or virtual table method ends, the value returned 1788** by this routine reverts to what it was before the trigger or virtual 1789** table method began.)^ 1790** 1791** ^An [INSERT] that fails due to a constraint violation is not a 1792** successful [INSERT] and does not change the value returned by this 1793** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1794** and INSERT OR ABORT make no changes to the return value of this 1795** routine when their insertion fails. ^(When INSERT OR REPLACE 1796** encounters a constraint violation, it does not fail. The 1797** INSERT continues to completion after deleting rows that caused 1798** the constraint problem so INSERT OR REPLACE will always change 1799** the return value of this interface.)^ 1800** 1801** ^For the purposes of this routine, an [INSERT] is considered to 1802** be successful even if it is subsequently rolled back. 1803** 1804** This function is accessible to SQL statements via the 1805** [last_insert_rowid() SQL function]. 1806** 1807** If a separate thread performs a new [INSERT] on the same 1808** database connection while the [sqlite3_last_insert_rowid()] 1809** function is running and thus changes the last insert [rowid], 1810** then the value returned by [sqlite3_last_insert_rowid()] is 1811** unpredictable and might not equal either the old or the new 1812** last insert [rowid]. 1813*/ 1814sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1815 1816/* 1817** CAPI3REF: Count The Number Of Rows Modified 1818** 1819** ^This function returns the number of database rows that were changed 1820** or inserted or deleted by the most recently completed SQL statement 1821** on the [database connection] specified by the first parameter. 1822** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1823** or [DELETE] statement are counted. Auxiliary changes caused by 1824** triggers or [foreign key actions] are not counted.)^ Use the 1825** [sqlite3_total_changes()] function to find the total number of changes 1826** including changes caused by triggers and foreign key actions. 1827** 1828** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1829** are not counted. Only real table changes are counted. 1830** 1831** ^(A "row change" is a change to a single row of a single table 1832** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1833** are changed as side effects of [REPLACE] constraint resolution, 1834** rollback, ABORT processing, [DROP TABLE], or by any other 1835** mechanisms do not count as direct row changes.)^ 1836** 1837** A "trigger context" is a scope of execution that begins and 1838** ends with the script of a [CREATE TRIGGER | trigger]. 1839** Most SQL statements are 1840** evaluated outside of any trigger. This is the "top level" 1841** trigger context. If a trigger fires from the top level, a 1842** new trigger context is entered for the duration of that one 1843** trigger. Subtriggers create subcontexts for their duration. 1844** 1845** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1846** not create a new trigger context. 1847** 1848** ^This function returns the number of direct row changes in the 1849** most recent INSERT, UPDATE, or DELETE statement within the same 1850** trigger context. 1851** 1852** ^Thus, when called from the top level, this function returns the 1853** number of changes in the most recent INSERT, UPDATE, or DELETE 1854** that also occurred at the top level. ^(Within the body of a trigger, 1855** the sqlite3_changes() interface can be called to find the number of 1856** changes in the most recently completed INSERT, UPDATE, or DELETE 1857** statement within the body of the same trigger. 1858** However, the number returned does not include changes 1859** caused by subtriggers since those have their own context.)^ 1860** 1861** See also the [sqlite3_total_changes()] interface, the 1862** [count_changes pragma], and the [changes() SQL function]. 1863** 1864** If a separate thread makes changes on the same database connection 1865** while [sqlite3_changes()] is running then the value returned 1866** is unpredictable and not meaningful. 1867*/ 1868int sqlite3_changes(sqlite3*); 1869 1870/* 1871** CAPI3REF: Total Number Of Rows Modified 1872** 1873** ^This function returns the number of row changes caused by [INSERT], 1874** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1875** ^(The count returned by sqlite3_total_changes() includes all changes 1876** from all [CREATE TRIGGER | trigger] contexts and changes made by 1877** [foreign key actions]. However, 1878** the count does not include changes used to implement [REPLACE] constraints, 1879** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1880** count does not include rows of views that fire an [INSTEAD OF trigger], 1881** though if the INSTEAD OF trigger makes changes of its own, those changes 1882** are counted.)^ 1883** ^The sqlite3_total_changes() function counts the changes as soon as 1884** the statement that makes them is completed (when the statement handle 1885** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1886** 1887** See also the [sqlite3_changes()] interface, the 1888** [count_changes pragma], and the [total_changes() SQL function]. 1889** 1890** If a separate thread makes changes on the same database connection 1891** while [sqlite3_total_changes()] is running then the value 1892** returned is unpredictable and not meaningful. 1893*/ 1894int sqlite3_total_changes(sqlite3*); 1895 1896/* 1897** CAPI3REF: Interrupt A Long-Running Query 1898** 1899** ^This function causes any pending database operation to abort and 1900** return at its earliest opportunity. This routine is typically 1901** called in response to a user action such as pressing "Cancel" 1902** or Ctrl-C where the user wants a long query operation to halt 1903** immediately. 1904** 1905** ^It is safe to call this routine from a thread different from the 1906** thread that is currently running the database operation. But it 1907** is not safe to call this routine with a [database connection] that 1908** is closed or might close before sqlite3_interrupt() returns. 1909** 1910** ^If an SQL operation is very nearly finished at the time when 1911** sqlite3_interrupt() is called, then it might not have an opportunity 1912** to be interrupted and might continue to completion. 1913** 1914** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1915** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1916** that is inside an explicit transaction, then the entire transaction 1917** will be rolled back automatically. 1918** 1919** ^The sqlite3_interrupt(D) call is in effect until all currently running 1920** SQL statements on [database connection] D complete. ^Any new SQL statements 1921** that are started after the sqlite3_interrupt() call and before the 1922** running statements reaches zero are interrupted as if they had been 1923** running prior to the sqlite3_interrupt() call. ^New SQL statements 1924** that are started after the running statement count reaches zero are 1925** not effected by the sqlite3_interrupt(). 1926** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1927** SQL statements is a no-op and has no effect on SQL statements 1928** that are started after the sqlite3_interrupt() call returns. 1929** 1930** If the database connection closes while [sqlite3_interrupt()] 1931** is running then bad things will likely happen. 1932*/ 1933void sqlite3_interrupt(sqlite3*); 1934 1935/* 1936** CAPI3REF: Determine If An SQL Statement Is Complete 1937** 1938** These routines are useful during command-line input to determine if the 1939** currently entered text seems to form a complete SQL statement or 1940** if additional input is needed before sending the text into 1941** SQLite for parsing. ^These routines return 1 if the input string 1942** appears to be a complete SQL statement. ^A statement is judged to be 1943** complete if it ends with a semicolon token and is not a prefix of a 1944** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1945** string literals or quoted identifier names or comments are not 1946** independent tokens (they are part of the token in which they are 1947** embedded) and thus do not count as a statement terminator. ^Whitespace 1948** and comments that follow the final semicolon are ignored. 1949** 1950** ^These routines return 0 if the statement is incomplete. ^If a 1951** memory allocation fails, then SQLITE_NOMEM is returned. 1952** 1953** ^These routines do not parse the SQL statements thus 1954** will not detect syntactically incorrect SQL. 1955** 1956** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1957** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1958** automatically by sqlite3_complete16(). If that initialization fails, 1959** then the return value from sqlite3_complete16() will be non-zero 1960** regardless of whether or not the input SQL is complete.)^ 1961** 1962** The input to [sqlite3_complete()] must be a zero-terminated 1963** UTF-8 string. 1964** 1965** The input to [sqlite3_complete16()] must be a zero-terminated 1966** UTF-16 string in native byte order. 1967*/ 1968int sqlite3_complete(const char *sql); 1969int sqlite3_complete16(const void *sql); 1970 1971/* 1972** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1973** 1974** ^This routine sets a callback function that might be invoked whenever 1975** an attempt is made to open a database table that another thread 1976** or process has locked. 1977** 1978** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1979** is returned immediately upon encountering the lock. ^If the busy callback 1980** is not NULL, then the callback might be invoked with two arguments. 1981** 1982** ^The first argument to the busy handler is a copy of the void* pointer which 1983** is the third argument to sqlite3_busy_handler(). ^The second argument to 1984** the busy handler callback is the number of times that the busy handler has 1985** been invoked for this locking event. ^If the 1986** busy callback returns 0, then no additional attempts are made to 1987** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1988** ^If the callback returns non-zero, then another attempt 1989** is made to open the database for reading and the cycle repeats. 1990** 1991** The presence of a busy handler does not guarantee that it will be invoked 1992** when there is lock contention. ^If SQLite determines that invoking the busy 1993** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1994** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1995** Consider a scenario where one process is holding a read lock that 1996** it is trying to promote to a reserved lock and 1997** a second process is holding a reserved lock that it is trying 1998** to promote to an exclusive lock. The first process cannot proceed 1999** because it is blocked by the second and the second process cannot 2000** proceed because it is blocked by the first. If both processes 2001** invoke the busy handlers, neither will make any progress. Therefore, 2002** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2003** will induce the first process to release its read lock and allow 2004** the second process to proceed. 2005** 2006** ^The default busy callback is NULL. 2007** 2008** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 2009** when SQLite is in the middle of a large transaction where all the 2010** changes will not fit into the in-memory cache. SQLite will 2011** already hold a RESERVED lock on the database file, but it needs 2012** to promote this lock to EXCLUSIVE so that it can spill cache 2013** pages into the database file without harm to concurrent 2014** readers. ^If it is unable to promote the lock, then the in-memory 2015** cache will be left in an inconsistent state and so the error 2016** code is promoted from the relatively benign [SQLITE_BUSY] to 2017** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 2018** forces an automatic rollback of the changes. See the 2019** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 2020** CorruptionFollowingBusyError</a> wiki page for a discussion of why 2021** this is important. 2022** 2023** ^(There can only be a single busy handler defined for each 2024** [database connection]. Setting a new busy handler clears any 2025** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2026** will also set or clear the busy handler. 2027** 2028** The busy callback should not take any actions which modify the 2029** database connection that invoked the busy handler. Any such actions 2030** result in undefined behavior. 2031** 2032** A busy handler must not close the database connection 2033** or [prepared statement] that invoked the busy handler. 2034*/ 2035int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 2036 2037/* 2038** CAPI3REF: Set A Busy Timeout 2039** 2040** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2041** for a specified amount of time when a table is locked. ^The handler 2042** will sleep multiple times until at least "ms" milliseconds of sleeping 2043** have accumulated. ^After at least "ms" milliseconds of sleeping, 2044** the handler returns 0 which causes [sqlite3_step()] to return 2045** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 2046** 2047** ^Calling this routine with an argument less than or equal to zero 2048** turns off all busy handlers. 2049** 2050** ^(There can only be a single busy handler for a particular 2051** [database connection] any any given moment. If another busy handler 2052** was defined (using [sqlite3_busy_handler()]) prior to calling 2053** this routine, that other busy handler is cleared.)^ 2054*/ 2055int sqlite3_busy_timeout(sqlite3*, int ms); 2056 2057/* 2058** CAPI3REF: Convenience Routines For Running Queries 2059** 2060** This is a legacy interface that is preserved for backwards compatibility. 2061** Use of this interface is not recommended. 2062** 2063** Definition: A <b>result table</b> is memory data structure created by the 2064** [sqlite3_get_table()] interface. A result table records the 2065** complete query results from one or more queries. 2066** 2067** The table conceptually has a number of rows and columns. But 2068** these numbers are not part of the result table itself. These 2069** numbers are obtained separately. Let N be the number of rows 2070** and M be the number of columns. 2071** 2072** A result table is an array of pointers to zero-terminated UTF-8 strings. 2073** There are (N+1)*M elements in the array. The first M pointers point 2074** to zero-terminated strings that contain the names of the columns. 2075** The remaining entries all point to query results. NULL values result 2076** in NULL pointers. All other values are in their UTF-8 zero-terminated 2077** string representation as returned by [sqlite3_column_text()]. 2078** 2079** A result table might consist of one or more memory allocations. 2080** It is not safe to pass a result table directly to [sqlite3_free()]. 2081** A result table should be deallocated using [sqlite3_free_table()]. 2082** 2083** ^(As an example of the result table format, suppose a query result 2084** is as follows: 2085** 2086** <blockquote><pre> 2087** Name | Age 2088** ----------------------- 2089** Alice | 43 2090** Bob | 28 2091** Cindy | 21 2092** </pre></blockquote> 2093** 2094** There are two column (M==2) and three rows (N==3). Thus the 2095** result table has 8 entries. Suppose the result table is stored 2096** in an array names azResult. Then azResult holds this content: 2097** 2098** <blockquote><pre> 2099** azResult[0] = "Name"; 2100** azResult[1] = "Age"; 2101** azResult[2] = "Alice"; 2102** azResult[3] = "43"; 2103** azResult[4] = "Bob"; 2104** azResult[5] = "28"; 2105** azResult[6] = "Cindy"; 2106** azResult[7] = "21"; 2107** </pre></blockquote>)^ 2108** 2109** ^The sqlite3_get_table() function evaluates one or more 2110** semicolon-separated SQL statements in the zero-terminated UTF-8 2111** string of its 2nd parameter and returns a result table to the 2112** pointer given in its 3rd parameter. 2113** 2114** After the application has finished with the result from sqlite3_get_table(), 2115** it must pass the result table pointer to sqlite3_free_table() in order to 2116** release the memory that was malloced. Because of the way the 2117** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2118** function must not try to call [sqlite3_free()] directly. Only 2119** [sqlite3_free_table()] is able to release the memory properly and safely. 2120** 2121** The sqlite3_get_table() interface is implemented as a wrapper around 2122** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2123** to any internal data structures of SQLite. It uses only the public 2124** interface defined here. As a consequence, errors that occur in the 2125** wrapper layer outside of the internal [sqlite3_exec()] call are not 2126** reflected in subsequent calls to [sqlite3_errcode()] or 2127** [sqlite3_errmsg()]. 2128*/ 2129int sqlite3_get_table( 2130 sqlite3 *db, /* An open database */ 2131 const char *zSql, /* SQL to be evaluated */ 2132 char ***pazResult, /* Results of the query */ 2133 int *pnRow, /* Number of result rows written here */ 2134 int *pnColumn, /* Number of result columns written here */ 2135 char **pzErrmsg /* Error msg written here */ 2136); 2137void sqlite3_free_table(char **result); 2138 2139/* 2140** CAPI3REF: Formatted String Printing Functions 2141** 2142** These routines are work-alikes of the "printf()" family of functions 2143** from the standard C library. 2144** 2145** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2146** results into memory obtained from [sqlite3_malloc()]. 2147** The strings returned by these two routines should be 2148** released by [sqlite3_free()]. ^Both routines return a 2149** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2150** memory to hold the resulting string. 2151** 2152** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2153** the standard C library. The result is written into the 2154** buffer supplied as the second parameter whose size is given by 2155** the first parameter. Note that the order of the 2156** first two parameters is reversed from snprintf().)^ This is an 2157** historical accident that cannot be fixed without breaking 2158** backwards compatibility. ^(Note also that sqlite3_snprintf() 2159** returns a pointer to its buffer instead of the number of 2160** characters actually written into the buffer.)^ We admit that 2161** the number of characters written would be a more useful return 2162** value but we cannot change the implementation of sqlite3_snprintf() 2163** now without breaking compatibility. 2164** 2165** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2166** guarantees that the buffer is always zero-terminated. ^The first 2167** parameter "n" is the total size of the buffer, including space for 2168** the zero terminator. So the longest string that can be completely 2169** written will be n-1 characters. 2170** 2171** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2172** 2173** These routines all implement some additional formatting 2174** options that are useful for constructing SQL statements. 2175** All of the usual printf() formatting options apply. In addition, there 2176** is are "%q", "%Q", and "%z" options. 2177** 2178** ^(The %q option works like %s in that it substitutes a nul-terminated 2179** string from the argument list. But %q also doubles every '\'' character. 2180** %q is designed for use inside a string literal.)^ By doubling each '\'' 2181** character it escapes that character and allows it to be inserted into 2182** the string. 2183** 2184** For example, assume the string variable zText contains text as follows: 2185** 2186** <blockquote><pre> 2187** char *zText = "It's a happy day!"; 2188** </pre></blockquote> 2189** 2190** One can use this text in an SQL statement as follows: 2191** 2192** <blockquote><pre> 2193** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2194** sqlite3_exec(db, zSQL, 0, 0, 0); 2195** sqlite3_free(zSQL); 2196** </pre></blockquote> 2197** 2198** Because the %q format string is used, the '\'' character in zText 2199** is escaped and the SQL generated is as follows: 2200** 2201** <blockquote><pre> 2202** INSERT INTO table1 VALUES('It''s a happy day!') 2203** </pre></blockquote> 2204** 2205** This is correct. Had we used %s instead of %q, the generated SQL 2206** would have looked like this: 2207** 2208** <blockquote><pre> 2209** INSERT INTO table1 VALUES('It's a happy day!'); 2210** </pre></blockquote> 2211** 2212** This second example is an SQL syntax error. As a general rule you should 2213** always use %q instead of %s when inserting text into a string literal. 2214** 2215** ^(The %Q option works like %q except it also adds single quotes around 2216** the outside of the total string. Additionally, if the parameter in the 2217** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2218** single quotes).)^ So, for example, one could say: 2219** 2220** <blockquote><pre> 2221** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2222** sqlite3_exec(db, zSQL, 0, 0, 0); 2223** sqlite3_free(zSQL); 2224** </pre></blockquote> 2225** 2226** The code above will render a correct SQL statement in the zSQL 2227** variable even if the zText variable is a NULL pointer. 2228** 2229** ^(The "%z" formatting option works like "%s" but with the 2230** addition that after the string has been read and copied into 2231** the result, [sqlite3_free()] is called on the input string.)^ 2232*/ 2233char *sqlite3_mprintf(const char*,...); 2234char *sqlite3_vmprintf(const char*, va_list); 2235char *sqlite3_snprintf(int,char*,const char*, ...); 2236char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2237 2238/* 2239** CAPI3REF: Memory Allocation Subsystem 2240** 2241** The SQLite core uses these three routines for all of its own 2242** internal memory allocation needs. "Core" in the previous sentence 2243** does not include operating-system specific VFS implementation. The 2244** Windows VFS uses native malloc() and free() for some operations. 2245** 2246** ^The sqlite3_malloc() routine returns a pointer to a block 2247** of memory at least N bytes in length, where N is the parameter. 2248** ^If sqlite3_malloc() is unable to obtain sufficient free 2249** memory, it returns a NULL pointer. ^If the parameter N to 2250** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2251** a NULL pointer. 2252** 2253** ^Calling sqlite3_free() with a pointer previously returned 2254** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2255** that it might be reused. ^The sqlite3_free() routine is 2256** a no-op if is called with a NULL pointer. Passing a NULL pointer 2257** to sqlite3_free() is harmless. After being freed, memory 2258** should neither be read nor written. Even reading previously freed 2259** memory might result in a segmentation fault or other severe error. 2260** Memory corruption, a segmentation fault, or other severe error 2261** might result if sqlite3_free() is called with a non-NULL pointer that 2262** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2263** 2264** ^(The sqlite3_realloc() interface attempts to resize a 2265** prior memory allocation to be at least N bytes, where N is the 2266** second parameter. The memory allocation to be resized is the first 2267** parameter.)^ ^ If the first parameter to sqlite3_realloc() 2268** is a NULL pointer then its behavior is identical to calling 2269** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 2270** ^If the second parameter to sqlite3_realloc() is zero or 2271** negative then the behavior is exactly the same as calling 2272** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 2273** ^sqlite3_realloc() returns a pointer to a memory allocation 2274** of at least N bytes in size or NULL if sufficient memory is unavailable. 2275** ^If M is the size of the prior allocation, then min(N,M) bytes 2276** of the prior allocation are copied into the beginning of buffer returned 2277** by sqlite3_realloc() and the prior allocation is freed. 2278** ^If sqlite3_realloc() returns NULL, then the prior allocation 2279** is not freed. 2280** 2281** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 2282** is always aligned to at least an 8 byte boundary, or to a 2283** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2284** option is used. 2285** 2286** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2287** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2288** implementation of these routines to be omitted. That capability 2289** is no longer provided. Only built-in memory allocators can be used. 2290** 2291** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2292** the system malloc() and free() directly when converting 2293** filenames between the UTF-8 encoding used by SQLite 2294** and whatever filename encoding is used by the particular Windows 2295** installation. Memory allocation errors were detected, but 2296** they were reported back as [SQLITE_CANTOPEN] or 2297** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2298** 2299** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2300** must be either NULL or else pointers obtained from a prior 2301** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2302** not yet been released. 2303** 2304** The application must not read or write any part of 2305** a block of memory after it has been released using 2306** [sqlite3_free()] or [sqlite3_realloc()]. 2307*/ 2308void *sqlite3_malloc(int); 2309void *sqlite3_realloc(void*, int); 2310void sqlite3_free(void*); 2311 2312/* 2313** CAPI3REF: Memory Allocator Statistics 2314** 2315** SQLite provides these two interfaces for reporting on the status 2316** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2317** routines, which form the built-in memory allocation subsystem. 2318** 2319** ^The [sqlite3_memory_used()] routine returns the number of bytes 2320** of memory currently outstanding (malloced but not freed). 2321** ^The [sqlite3_memory_highwater()] routine returns the maximum 2322** value of [sqlite3_memory_used()] since the high-water mark 2323** was last reset. ^The values returned by [sqlite3_memory_used()] and 2324** [sqlite3_memory_highwater()] include any overhead 2325** added by SQLite in its implementation of [sqlite3_malloc()], 2326** but not overhead added by the any underlying system library 2327** routines that [sqlite3_malloc()] may call. 2328** 2329** ^The memory high-water mark is reset to the current value of 2330** [sqlite3_memory_used()] if and only if the parameter to 2331** [sqlite3_memory_highwater()] is true. ^The value returned 2332** by [sqlite3_memory_highwater(1)] is the high-water mark 2333** prior to the reset. 2334*/ 2335sqlite3_int64 sqlite3_memory_used(void); 2336sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2337 2338/* 2339** CAPI3REF: Pseudo-Random Number Generator 2340** 2341** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2342** select random [ROWID | ROWIDs] when inserting new records into a table that 2343** already uses the largest possible [ROWID]. The PRNG is also used for 2344** the build-in random() and randomblob() SQL functions. This interface allows 2345** applications to access the same PRNG for other purposes. 2346** 2347** ^A call to this routine stores N bytes of randomness into buffer P. 2348** 2349** ^The first time this routine is invoked (either internally or by 2350** the application) the PRNG is seeded using randomness obtained 2351** from the xRandomness method of the default [sqlite3_vfs] object. 2352** ^On all subsequent invocations, the pseudo-randomness is generated 2353** internally and without recourse to the [sqlite3_vfs] xRandomness 2354** method. 2355*/ 2356void sqlite3_randomness(int N, void *P); 2357 2358/* 2359** CAPI3REF: Compile-Time Authorization Callbacks 2360** 2361** ^This routine registers an authorizer callback with a particular 2362** [database connection], supplied in the first argument. 2363** ^The authorizer callback is invoked as SQL statements are being compiled 2364** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2365** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2366** points during the compilation process, as logic is being created 2367** to perform various actions, the authorizer callback is invoked to 2368** see if those actions are allowed. ^The authorizer callback should 2369** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2370** specific action but allow the SQL statement to continue to be 2371** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2372** rejected with an error. ^If the authorizer callback returns 2373** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2374** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2375** the authorizer will fail with an error message. 2376** 2377** When the callback returns [SQLITE_OK], that means the operation 2378** requested is ok. ^When the callback returns [SQLITE_DENY], the 2379** [sqlite3_prepare_v2()] or equivalent call that triggered the 2380** authorizer will fail with an error message explaining that 2381** access is denied. 2382** 2383** ^The first parameter to the authorizer callback is a copy of the third 2384** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2385** to the callback is an integer [SQLITE_COPY | action code] that specifies 2386** the particular action to be authorized. ^The third through sixth parameters 2387** to the callback are zero-terminated strings that contain additional 2388** details about the action to be authorized. 2389** 2390** ^If the action code is [SQLITE_READ] 2391** and the callback returns [SQLITE_IGNORE] then the 2392** [prepared statement] statement is constructed to substitute 2393** a NULL value in place of the table column that would have 2394** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2395** return can be used to deny an untrusted user access to individual 2396** columns of a table. 2397** ^If the action code is [SQLITE_DELETE] and the callback returns 2398** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2399** [truncate optimization] is disabled and all rows are deleted individually. 2400** 2401** An authorizer is used when [sqlite3_prepare | preparing] 2402** SQL statements from an untrusted source, to ensure that the SQL statements 2403** do not try to access data they are not allowed to see, or that they do not 2404** try to execute malicious statements that damage the database. For 2405** example, an application may allow a user to enter arbitrary 2406** SQL queries for evaluation by a database. But the application does 2407** not want the user to be able to make arbitrary changes to the 2408** database. An authorizer could then be put in place while the 2409** user-entered SQL is being [sqlite3_prepare | prepared] that 2410** disallows everything except [SELECT] statements. 2411** 2412** Applications that need to process SQL from untrusted sources 2413** might also consider lowering resource limits using [sqlite3_limit()] 2414** and limiting database size using the [max_page_count] [PRAGMA] 2415** in addition to using an authorizer. 2416** 2417** ^(Only a single authorizer can be in place on a database connection 2418** at a time. Each call to sqlite3_set_authorizer overrides the 2419** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2420** The authorizer is disabled by default. 2421** 2422** The authorizer callback must not do anything that will modify 2423** the database connection that invoked the authorizer callback. 2424** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2425** database connections for the meaning of "modify" in this paragraph. 2426** 2427** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2428** statement might be re-prepared during [sqlite3_step()] due to a 2429** schema change. Hence, the application should ensure that the 2430** correct authorizer callback remains in place during the [sqlite3_step()]. 2431** 2432** ^Note that the authorizer callback is invoked only during 2433** [sqlite3_prepare()] or its variants. Authorization is not 2434** performed during statement evaluation in [sqlite3_step()], unless 2435** as stated in the previous paragraph, sqlite3_step() invokes 2436** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2437*/ 2438int sqlite3_set_authorizer( 2439 sqlite3*, 2440 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2441 void *pUserData 2442); 2443 2444/* 2445** CAPI3REF: Authorizer Return Codes 2446** 2447** The [sqlite3_set_authorizer | authorizer callback function] must 2448** return either [SQLITE_OK] or one of these two constants in order 2449** to signal SQLite whether or not the action is permitted. See the 2450** [sqlite3_set_authorizer | authorizer documentation] for additional 2451** information. 2452** 2453** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code] 2454** from the [sqlite3_vtab_on_conflict()] interface. 2455*/ 2456#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2457#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2458 2459/* 2460** CAPI3REF: Authorizer Action Codes 2461** 2462** The [sqlite3_set_authorizer()] interface registers a callback function 2463** that is invoked to authorize certain SQL statement actions. The 2464** second parameter to the callback is an integer code that specifies 2465** what action is being authorized. These are the integer action codes that 2466** the authorizer callback may be passed. 2467** 2468** These action code values signify what kind of operation is to be 2469** authorized. The 3rd and 4th parameters to the authorization 2470** callback function will be parameters or NULL depending on which of these 2471** codes is used as the second parameter. ^(The 5th parameter to the 2472** authorizer callback is the name of the database ("main", "temp", 2473** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2474** is the name of the inner-most trigger or view that is responsible for 2475** the access attempt or NULL if this access attempt is directly from 2476** top-level SQL code. 2477*/ 2478/******************************************* 3rd ************ 4th ***********/ 2479#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2480#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2481#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2482#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2483#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2484#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2485#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2486#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2487#define SQLITE_DELETE 9 /* Table Name NULL */ 2488#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2489#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2490#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2491#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2492#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2493#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2494#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2495#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2496#define SQLITE_INSERT 18 /* Table Name NULL */ 2497#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2498#define SQLITE_READ 20 /* Table Name Column Name */ 2499#define SQLITE_SELECT 21 /* NULL NULL */ 2500#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2501#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2502#define SQLITE_ATTACH 24 /* Filename NULL */ 2503#define SQLITE_DETACH 25 /* Database Name NULL */ 2504#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2505#define SQLITE_REINDEX 27 /* Index Name NULL */ 2506#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2507#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2508#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2509#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2510#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2511#define SQLITE_COPY 0 /* No longer used */ 2512 2513/* 2514** CAPI3REF: Tracing And Profiling Functions 2515** 2516** These routines register callback functions that can be used for 2517** tracing and profiling the execution of SQL statements. 2518** 2519** ^The callback function registered by sqlite3_trace() is invoked at 2520** various times when an SQL statement is being run by [sqlite3_step()]. 2521** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2522** SQL statement text as the statement first begins executing. 2523** ^(Additional sqlite3_trace() callbacks might occur 2524** as each triggered subprogram is entered. The callbacks for triggers 2525** contain a UTF-8 SQL comment that identifies the trigger.)^ 2526** 2527** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2528** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2529** 2530** ^The callback function registered by sqlite3_profile() is invoked 2531** as each SQL statement finishes. ^The profile callback contains 2532** the original statement text and an estimate of wall-clock time 2533** of how long that statement took to run. ^The profile callback 2534** time is in units of nanoseconds, however the current implementation 2535** is only capable of millisecond resolution so the six least significant 2536** digits in the time are meaningless. Future versions of SQLite 2537** might provide greater resolution on the profiler callback. The 2538** sqlite3_profile() function is considered experimental and is 2539** subject to change in future versions of SQLite. 2540*/ 2541void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2542SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2543 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2544 2545/* 2546** CAPI3REF: Query Progress Callbacks 2547** 2548** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2549** function X to be invoked periodically during long running calls to 2550** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2551** database connection D. An example use for this 2552** interface is to keep a GUI updated during a large query. 2553** 2554** ^The parameter P is passed through as the only parameter to the 2555** callback function X. ^The parameter N is the number of 2556** [virtual machine instructions] that are evaluated between successive 2557** invocations of the callback X. 2558** 2559** ^Only a single progress handler may be defined at one time per 2560** [database connection]; setting a new progress handler cancels the 2561** old one. ^Setting parameter X to NULL disables the progress handler. 2562** ^The progress handler is also disabled by setting N to a value less 2563** than 1. 2564** 2565** ^If the progress callback returns non-zero, the operation is 2566** interrupted. This feature can be used to implement a 2567** "Cancel" button on a GUI progress dialog box. 2568** 2569** The progress handler callback must not do anything that will modify 2570** the database connection that invoked the progress handler. 2571** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2572** database connections for the meaning of "modify" in this paragraph. 2573** 2574*/ 2575void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2576 2577/* 2578** CAPI3REF: Opening A New Database Connection 2579** 2580** ^These routines open an SQLite database file as specified by the 2581** filename argument. ^The filename argument is interpreted as UTF-8 for 2582** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2583** order for sqlite3_open16(). ^(A [database connection] handle is usually 2584** returned in *ppDb, even if an error occurs. The only exception is that 2585** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2586** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2587** object.)^ ^(If the database is opened (and/or created) successfully, then 2588** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2589** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2590** an English language description of the error following a failure of any 2591** of the sqlite3_open() routines. 2592** 2593** ^The default encoding for the database will be UTF-8 if 2594** sqlite3_open() or sqlite3_open_v2() is called and 2595** UTF-16 in the native byte order if sqlite3_open16() is used. 2596** 2597** Whether or not an error occurs when it is opened, resources 2598** associated with the [database connection] handle should be released by 2599** passing it to [sqlite3_close()] when it is no longer required. 2600** 2601** The sqlite3_open_v2() interface works like sqlite3_open() 2602** except that it accepts two additional parameters for additional control 2603** over the new database connection. ^(The flags parameter to 2604** sqlite3_open_v2() can take one of 2605** the following three values, optionally combined with the 2606** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2607** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2608** 2609** <dl> 2610** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2611** <dd>The database is opened in read-only mode. If the database does not 2612** already exist, an error is returned.</dd>)^ 2613** 2614** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2615** <dd>The database is opened for reading and writing if possible, or reading 2616** only if the file is write protected by the operating system. In either 2617** case the database must already exist, otherwise an error is returned.</dd>)^ 2618** 2619** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2620** <dd>The database is opened for reading and writing, and is created if 2621** it does not already exist. This is the behavior that is always used for 2622** sqlite3_open() and sqlite3_open16().</dd>)^ 2623** </dl> 2624** 2625** If the 3rd parameter to sqlite3_open_v2() is not one of the 2626** combinations shown above optionally combined with other 2627** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2628** then the behavior is undefined. 2629** 2630** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2631** opens in the multi-thread [threading mode] as long as the single-thread 2632** mode has not been set at compile-time or start-time. ^If the 2633** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2634** in the serialized [threading mode] unless single-thread was 2635** previously selected at compile-time or start-time. 2636** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2637** eligible to use [shared cache mode], regardless of whether or not shared 2638** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2639** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2640** participate in [shared cache mode] even if it is enabled. 2641** 2642** ^The fourth parameter to sqlite3_open_v2() is the name of the 2643** [sqlite3_vfs] object that defines the operating system interface that 2644** the new database connection should use. ^If the fourth parameter is 2645** a NULL pointer then the default [sqlite3_vfs] object is used. 2646** 2647** ^If the filename is ":memory:", then a private, temporary in-memory database 2648** is created for the connection. ^This in-memory database will vanish when 2649** the database connection is closed. Future versions of SQLite might 2650** make use of additional special filenames that begin with the ":" character. 2651** It is recommended that when a database filename actually does begin with 2652** a ":" character you should prefix the filename with a pathname such as 2653** "./" to avoid ambiguity. 2654** 2655** ^If the filename is an empty string, then a private, temporary 2656** on-disk database will be created. ^This private database will be 2657** automatically deleted as soon as the database connection is closed. 2658** 2659** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2660** 2661** ^If [URI filename] interpretation is enabled, and the filename argument 2662** begins with "file:", then the filename is interpreted as a URI. ^URI 2663** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2664** set in the fourth argument to sqlite3_open_v2(), or if it has 2665** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2666** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2667** As of SQLite version 3.7.7, URI filename interpretation is turned off 2668** by default, but future releases of SQLite might enable URI filename 2669** interpretation by default. See "[URI filenames]" for additional 2670** information. 2671** 2672** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2673** authority, then it must be either an empty string or the string 2674** "localhost". ^If the authority is not an empty string or "localhost", an 2675** error is returned to the caller. ^The fragment component of a URI, if 2676** present, is ignored. 2677** 2678** ^SQLite uses the path component of the URI as the name of the disk file 2679** which contains the database. ^If the path begins with a '/' character, 2680** then it is interpreted as an absolute path. ^If the path does not begin 2681** with a '/' (meaning that the authority section is omitted from the URI) 2682** then the path is interpreted as a relative path. 2683** ^On windows, the first component of an absolute path 2684** is a drive specification (e.g. "C:"). 2685** 2686** [[core URI query parameters]] 2687** The query component of a URI may contain parameters that are interpreted 2688** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2689** SQLite interprets the following three query parameters: 2690** 2691** <ul> 2692** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2693** a VFS object that provides the operating system interface that should 2694** be used to access the database file on disk. ^If this option is set to 2695** an empty string the default VFS object is used. ^Specifying an unknown 2696** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2697** present, then the VFS specified by the option takes precedence over 2698** the value passed as the fourth parameter to sqlite3_open_v2(). 2699** 2700** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 2701** "rwc", or "memory". Attempting to set it to any other value is 2702** an error)^. 2703** ^If "ro" is specified, then the database is opened for read-only 2704** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2705** third argument to sqlite3_open_v2(). ^If the mode option is set to 2706** "rw", then the database is opened for read-write (but not create) 2707** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2708** been set. ^Value "rwc" is equivalent to setting both 2709** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 2710** set to "memory" then a pure [in-memory database] that never reads 2711** or writes from disk is used. ^It is an error to specify a value for 2712** the mode parameter that is less restrictive than that specified by 2713** the flags passed in the third parameter to sqlite3_open_v2(). 2714** 2715** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2716** "private". ^Setting it to "shared" is equivalent to setting the 2717** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2718** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2719** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2720** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2721** a URI filename, its value overrides any behavior requested by setting 2722** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2723** </ul> 2724** 2725** ^Specifying an unknown parameter in the query component of a URI is not an 2726** error. Future versions of SQLite might understand additional query 2727** parameters. See "[query parameters with special meaning to SQLite]" for 2728** additional information. 2729** 2730** [[URI filename examples]] <h3>URI filename examples</h3> 2731** 2732** <table border="1" align=center cellpadding=5> 2733** <tr><th> URI filenames <th> Results 2734** <tr><td> file:data.db <td> 2735** Open the file "data.db" in the current directory. 2736** <tr><td> file:/home/fred/data.db<br> 2737** file:///home/fred/data.db <br> 2738** file://localhost/home/fred/data.db <br> <td> 2739** Open the database file "/home/fred/data.db". 2740** <tr><td> file://darkstar/home/fred/data.db <td> 2741** An error. "darkstar" is not a recognized authority. 2742** <tr><td style="white-space:nowrap"> 2743** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2744** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2745** C:. Note that the %20 escaping in this example is not strictly 2746** necessary - space characters can be used literally 2747** in URI filenames. 2748** <tr><td> file:data.db?mode=ro&cache=private <td> 2749** Open file "data.db" in the current directory for read-only access. 2750** Regardless of whether or not shared-cache mode is enabled by 2751** default, use a private cache. 2752** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td> 2753** Open file "/home/fred/data.db". Use the special VFS "unix-nolock". 2754** <tr><td> file:data.db?mode=readonly <td> 2755** An error. "readonly" is not a valid option for the "mode" parameter. 2756** </table> 2757** 2758** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2759** query components of a URI. A hexadecimal escape sequence consists of a 2760** percent sign - "%" - followed by exactly two hexadecimal digits 2761** specifying an octet value. ^Before the path or query components of a 2762** URI filename are interpreted, they are encoded using UTF-8 and all 2763** hexadecimal escape sequences replaced by a single byte containing the 2764** corresponding octet. If this process generates an invalid UTF-8 encoding, 2765** the results are undefined. 2766** 2767** <b>Note to Windows users:</b> The encoding used for the filename argument 2768** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2769** codepage is currently defined. Filenames containing international 2770** characters must be converted to UTF-8 prior to passing them into 2771** sqlite3_open() or sqlite3_open_v2(). 2772** 2773** <b>Note to Windows Runtime users:</b> The temporary directory must be set 2774** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 2775** features that require the use of temporary files may fail. 2776** 2777** See also: [sqlite3_temp_directory] 2778*/ 2779int sqlite3_open( 2780 const char *filename, /* Database filename (UTF-8) */ 2781 sqlite3 **ppDb /* OUT: SQLite db handle */ 2782); 2783int sqlite3_open16( 2784 const void *filename, /* Database filename (UTF-16) */ 2785 sqlite3 **ppDb /* OUT: SQLite db handle */ 2786); 2787int sqlite3_open_v2( 2788 const char *filename, /* Database filename (UTF-8) */ 2789 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2790 int flags, /* Flags */ 2791 const char *zVfs /* Name of VFS module to use */ 2792); 2793 2794/* 2795** CAPI3REF: Obtain Values For URI Parameters 2796** 2797** These are utility routines, useful to VFS implementations, that check 2798** to see if a database file was a URI that contained a specific query 2799** parameter, and if so obtains the value of that query parameter. 2800** 2801** If F is the database filename pointer passed into the xOpen() method of 2802** a VFS implementation when the flags parameter to xOpen() has one or 2803** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 2804** P is the name of the query parameter, then 2805** sqlite3_uri_parameter(F,P) returns the value of the P 2806** parameter if it exists or a NULL pointer if P does not appear as a 2807** query parameter on F. If P is a query parameter of F 2808** has no explicit value, then sqlite3_uri_parameter(F,P) returns 2809** a pointer to an empty string. 2810** 2811** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 2812** parameter and returns true (1) or false (0) according to the value 2813** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 2814** value of query parameter P is one of "yes", "true", or "on" in any 2815** case or if the value begins with a non-zero number. The 2816** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 2817** query parameter P is one of "no", "false", or "off" in any case or 2818** if the value begins with a numeric zero. If P is not a query 2819** parameter on F or if the value of P is does not match any of the 2820** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 2821** 2822** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 2823** 64-bit signed integer and returns that integer, or D if P does not 2824** exist. If the value of P is something other than an integer, then 2825** zero is returned. 2826** 2827** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 2828** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 2829** is not a database file pathname pointer that SQLite passed into the xOpen 2830** VFS method, then the behavior of this routine is undefined and probably 2831** undesirable. 2832*/ 2833const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 2834int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 2835sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 2836 2837 2838/* 2839** CAPI3REF: Error Codes And Messages 2840** 2841** ^The sqlite3_errcode() interface returns the numeric [result code] or 2842** [extended result code] for the most recent failed sqlite3_* API call 2843** associated with a [database connection]. If a prior API call failed 2844** but the most recent API call succeeded, the return value from 2845** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2846** interface is the same except that it always returns the 2847** [extended result code] even when extended result codes are 2848** disabled. 2849** 2850** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2851** text that describes the error, as either UTF-8 or UTF-16 respectively. 2852** ^(Memory to hold the error message string is managed internally. 2853** The application does not need to worry about freeing the result. 2854** However, the error string might be overwritten or deallocated by 2855** subsequent calls to other SQLite interface functions.)^ 2856** 2857** ^The sqlite3_errstr() interface returns the English-language text 2858** that describes the [result code], as UTF-8. 2859** ^(Memory to hold the error message string is managed internally 2860** and must not be freed by the application)^. 2861** 2862** When the serialized [threading mode] is in use, it might be the 2863** case that a second error occurs on a separate thread in between 2864** the time of the first error and the call to these interfaces. 2865** When that happens, the second error will be reported since these 2866** interfaces always report the most recent result. To avoid 2867** this, each thread can obtain exclusive use of the [database connection] D 2868** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2869** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2870** all calls to the interfaces listed here are completed. 2871** 2872** If an interface fails with SQLITE_MISUSE, that means the interface 2873** was invoked incorrectly by the application. In that case, the 2874** error code and message may or may not be set. 2875*/ 2876int sqlite3_errcode(sqlite3 *db); 2877int sqlite3_extended_errcode(sqlite3 *db); 2878const char *sqlite3_errmsg(sqlite3*); 2879const void *sqlite3_errmsg16(sqlite3*); 2880const char *sqlite3_errstr(int); 2881 2882/* 2883** CAPI3REF: SQL Statement Object 2884** KEYWORDS: {prepared statement} {prepared statements} 2885** 2886** An instance of this object represents a single SQL statement. 2887** This object is variously known as a "prepared statement" or a 2888** "compiled SQL statement" or simply as a "statement". 2889** 2890** The life of a statement object goes something like this: 2891** 2892** <ol> 2893** <li> Create the object using [sqlite3_prepare_v2()] or a related 2894** function. 2895** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2896** interfaces. 2897** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2898** <li> Reset the statement using [sqlite3_reset()] then go back 2899** to step 2. Do this zero or more times. 2900** <li> Destroy the object using [sqlite3_finalize()]. 2901** </ol> 2902** 2903** Refer to documentation on individual methods above for additional 2904** information. 2905*/ 2906typedef struct sqlite3_stmt sqlite3_stmt; 2907 2908/* 2909** CAPI3REF: Run-time Limits 2910** 2911** ^(This interface allows the size of various constructs to be limited 2912** on a connection by connection basis. The first parameter is the 2913** [database connection] whose limit is to be set or queried. The 2914** second parameter is one of the [limit categories] that define a 2915** class of constructs to be size limited. The third parameter is the 2916** new limit for that construct.)^ 2917** 2918** ^If the new limit is a negative number, the limit is unchanged. 2919** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 2920** [limits | hard upper bound] 2921** set at compile-time by a C preprocessor macro called 2922** [limits | SQLITE_MAX_<i>NAME</i>]. 2923** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2924** ^Attempts to increase a limit above its hard upper bound are 2925** silently truncated to the hard upper bound. 2926** 2927** ^Regardless of whether or not the limit was changed, the 2928** [sqlite3_limit()] interface returns the prior value of the limit. 2929** ^Hence, to find the current value of a limit without changing it, 2930** simply invoke this interface with the third parameter set to -1. 2931** 2932** Run-time limits are intended for use in applications that manage 2933** both their own internal database and also databases that are controlled 2934** by untrusted external sources. An example application might be a 2935** web browser that has its own databases for storing history and 2936** separate databases controlled by JavaScript applications downloaded 2937** off the Internet. The internal databases can be given the 2938** large, default limits. Databases managed by external sources can 2939** be given much smaller limits designed to prevent a denial of service 2940** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2941** interface to further control untrusted SQL. The size of the database 2942** created by an untrusted script can be contained using the 2943** [max_page_count] [PRAGMA]. 2944** 2945** New run-time limit categories may be added in future releases. 2946*/ 2947int sqlite3_limit(sqlite3*, int id, int newVal); 2948 2949/* 2950** CAPI3REF: Run-Time Limit Categories 2951** KEYWORDS: {limit category} {*limit categories} 2952** 2953** These constants define various performance limits 2954** that can be lowered at run-time using [sqlite3_limit()]. 2955** The synopsis of the meanings of the various limits is shown below. 2956** Additional information is available at [limits | Limits in SQLite]. 2957** 2958** <dl> 2959** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2960** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 2961** 2962** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2963** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2964** 2965** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2966** <dd>The maximum number of columns in a table definition or in the 2967** result set of a [SELECT] or the maximum number of columns in an index 2968** or in an ORDER BY or GROUP BY clause.</dd>)^ 2969** 2970** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2971** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2972** 2973** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2974** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2975** 2976** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2977** <dd>The maximum number of instructions in a virtual machine program 2978** used to implement an SQL statement. This limit is not currently 2979** enforced, though that might be added in some future release of 2980** SQLite.</dd>)^ 2981** 2982** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2983** <dd>The maximum number of arguments on a function.</dd>)^ 2984** 2985** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2986** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2987** 2988** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 2989** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2990** <dd>The maximum length of the pattern argument to the [LIKE] or 2991** [GLOB] operators.</dd>)^ 2992** 2993** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 2994** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2995** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 2996** 2997** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2998** <dd>The maximum depth of recursion for triggers.</dd>)^ 2999** </dl> 3000*/ 3001#define SQLITE_LIMIT_LENGTH 0 3002#define SQLITE_LIMIT_SQL_LENGTH 1 3003#define SQLITE_LIMIT_COLUMN 2 3004#define SQLITE_LIMIT_EXPR_DEPTH 3 3005#define SQLITE_LIMIT_COMPOUND_SELECT 4 3006#define SQLITE_LIMIT_VDBE_OP 5 3007#define SQLITE_LIMIT_FUNCTION_ARG 6 3008#define SQLITE_LIMIT_ATTACHED 7 3009#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3010#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3011#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3012 3013/* 3014** CAPI3REF: Compiling An SQL Statement 3015** KEYWORDS: {SQL statement compiler} 3016** 3017** To execute an SQL query, it must first be compiled into a byte-code 3018** program using one of these routines. 3019** 3020** The first argument, "db", is a [database connection] obtained from a 3021** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3022** [sqlite3_open16()]. The database connection must not have been closed. 3023** 3024** The second argument, "zSql", is the statement to be compiled, encoded 3025** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 3026** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 3027** use UTF-16. 3028** 3029** ^If the nByte argument is less than zero, then zSql is read up to the 3030** first zero terminator. ^If nByte is non-negative, then it is the maximum 3031** number of bytes read from zSql. ^When nByte is non-negative, the 3032** zSql string ends at either the first '\000' or '\u0000' character or 3033** the nByte-th byte, whichever comes first. If the caller knows 3034** that the supplied string is nul-terminated, then there is a small 3035** performance advantage to be gained by passing an nByte parameter that 3036** is equal to the number of bytes in the input string <i>including</i> 3037** the nul-terminator bytes as this saves SQLite from having to 3038** make a copy of the input string. 3039** 3040** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3041** past the end of the first SQL statement in zSql. These routines only 3042** compile the first statement in zSql, so *pzTail is left pointing to 3043** what remains uncompiled. 3044** 3045** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3046** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3047** to NULL. ^If the input text contains no SQL (if the input is an empty 3048** string or a comment) then *ppStmt is set to NULL. 3049** The calling procedure is responsible for deleting the compiled 3050** SQL statement using [sqlite3_finalize()] after it has finished with it. 3051** ppStmt may not be NULL. 3052** 3053** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3054** otherwise an [error code] is returned. 3055** 3056** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 3057** recommended for all new programs. The two older interfaces are retained 3058** for backwards compatibility, but their use is discouraged. 3059** ^In the "v2" interfaces, the prepared statement 3060** that is returned (the [sqlite3_stmt] object) contains a copy of the 3061** original SQL text. This causes the [sqlite3_step()] interface to 3062** behave differently in three ways: 3063** 3064** <ol> 3065** <li> 3066** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3067** always used to do, [sqlite3_step()] will automatically recompile the SQL 3068** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3069** retries will occur before sqlite3_step() gives up and returns an error. 3070** </li> 3071** 3072** <li> 3073** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3074** [error codes] or [extended error codes]. ^The legacy behavior was that 3075** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3076** and the application would have to make a second call to [sqlite3_reset()] 3077** in order to find the underlying cause of the problem. With the "v2" prepare 3078** interfaces, the underlying reason for the error is returned immediately. 3079** </li> 3080** 3081** <li> 3082** ^If the specific value bound to [parameter | host parameter] in the 3083** WHERE clause might influence the choice of query plan for a statement, 3084** then the statement will be automatically recompiled, as if there had been 3085** a schema change, on the first [sqlite3_step()] call following any change 3086** to the [sqlite3_bind_text | bindings] of that [parameter]. 3087** ^The specific value of WHERE-clause [parameter] might influence the 3088** choice of query plan if the parameter is the left-hand side of a [LIKE] 3089** or [GLOB] operator or if the parameter is compared to an indexed column 3090** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3091** the 3092** </li> 3093** </ol> 3094*/ 3095int sqlite3_prepare( 3096 sqlite3 *db, /* Database handle */ 3097 const char *zSql, /* SQL statement, UTF-8 encoded */ 3098 int nByte, /* Maximum length of zSql in bytes. */ 3099 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3100 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3101); 3102int sqlite3_prepare_v2( 3103 sqlite3 *db, /* Database handle */ 3104 const char *zSql, /* SQL statement, UTF-8 encoded */ 3105 int nByte, /* Maximum length of zSql in bytes. */ 3106 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3107 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3108); 3109int sqlite3_prepare16( 3110 sqlite3 *db, /* Database handle */ 3111 const void *zSql, /* SQL statement, UTF-16 encoded */ 3112 int nByte, /* Maximum length of zSql in bytes. */ 3113 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3114 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3115); 3116int sqlite3_prepare16_v2( 3117 sqlite3 *db, /* Database handle */ 3118 const void *zSql, /* SQL statement, UTF-16 encoded */ 3119 int nByte, /* Maximum length of zSql in bytes. */ 3120 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3121 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3122); 3123 3124/* 3125** CAPI3REF: Retrieving Statement SQL 3126** 3127** ^This interface can be used to retrieve a saved copy of the original 3128** SQL text used to create a [prepared statement] if that statement was 3129** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 3130*/ 3131const char *sqlite3_sql(sqlite3_stmt *pStmt); 3132 3133/* 3134** CAPI3REF: Determine If An SQL Statement Writes The Database 3135** 3136** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3137** and only if the [prepared statement] X makes no direct changes to 3138** the content of the database file. 3139** 3140** Note that [application-defined SQL functions] or 3141** [virtual tables] might change the database indirectly as a side effect. 3142** ^(For example, if an application defines a function "eval()" that 3143** calls [sqlite3_exec()], then the following SQL statement would 3144** change the database file through side-effects: 3145** 3146** <blockquote><pre> 3147** SELECT eval('DELETE FROM t1') FROM t2; 3148** </pre></blockquote> 3149** 3150** But because the [SELECT] statement does not change the database file 3151** directly, sqlite3_stmt_readonly() would still return true.)^ 3152** 3153** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3154** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3155** since the statements themselves do not actually modify the database but 3156** rather they control the timing of when other statements modify the 3157** database. ^The [ATTACH] and [DETACH] statements also cause 3158** sqlite3_stmt_readonly() to return true since, while those statements 3159** change the configuration of a database connection, they do not make 3160** changes to the content of the database files on disk. 3161*/ 3162int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3163 3164/* 3165** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3166** 3167** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3168** [prepared statement] S has been stepped at least once using 3169** [sqlite3_step(S)] but has not run to completion and/or has not 3170** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3171** interface returns false if S is a NULL pointer. If S is not a 3172** NULL pointer and is not a pointer to a valid [prepared statement] 3173** object, then the behavior is undefined and probably undesirable. 3174** 3175** This interface can be used in combination [sqlite3_next_stmt()] 3176** to locate all prepared statements associated with a database 3177** connection that are in need of being reset. This can be used, 3178** for example, in diagnostic routines to search for prepared 3179** statements that are holding a transaction open. 3180*/ 3181int sqlite3_stmt_busy(sqlite3_stmt*); 3182 3183/* 3184** CAPI3REF: Dynamically Typed Value Object 3185** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3186** 3187** SQLite uses the sqlite3_value object to represent all values 3188** that can be stored in a database table. SQLite uses dynamic typing 3189** for the values it stores. ^Values stored in sqlite3_value objects 3190** can be integers, floating point values, strings, BLOBs, or NULL. 3191** 3192** An sqlite3_value object may be either "protected" or "unprotected". 3193** Some interfaces require a protected sqlite3_value. Other interfaces 3194** will accept either a protected or an unprotected sqlite3_value. 3195** Every interface that accepts sqlite3_value arguments specifies 3196** whether or not it requires a protected sqlite3_value. 3197** 3198** The terms "protected" and "unprotected" refer to whether or not 3199** a mutex is held. An internal mutex is held for a protected 3200** sqlite3_value object but no mutex is held for an unprotected 3201** sqlite3_value object. If SQLite is compiled to be single-threaded 3202** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3203** or if SQLite is run in one of reduced mutex modes 3204** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3205** then there is no distinction between protected and unprotected 3206** sqlite3_value objects and they can be used interchangeably. However, 3207** for maximum code portability it is recommended that applications 3208** still make the distinction between protected and unprotected 3209** sqlite3_value objects even when not strictly required. 3210** 3211** ^The sqlite3_value objects that are passed as parameters into the 3212** implementation of [application-defined SQL functions] are protected. 3213** ^The sqlite3_value object returned by 3214** [sqlite3_column_value()] is unprotected. 3215** Unprotected sqlite3_value objects may only be used with 3216** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3217** The [sqlite3_value_blob | sqlite3_value_type()] family of 3218** interfaces require protected sqlite3_value objects. 3219*/ 3220typedef struct Mem sqlite3_value; 3221 3222/* 3223** CAPI3REF: SQL Function Context Object 3224** 3225** The context in which an SQL function executes is stored in an 3226** sqlite3_context object. ^A pointer to an sqlite3_context object 3227** is always first parameter to [application-defined SQL functions]. 3228** The application-defined SQL function implementation will pass this 3229** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3230** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3231** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3232** and/or [sqlite3_set_auxdata()]. 3233*/ 3234typedef struct sqlite3_context sqlite3_context; 3235 3236/* 3237** CAPI3REF: Binding Values To Prepared Statements 3238** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3239** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3240** 3241** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3242** literals may be replaced by a [parameter] that matches one of following 3243** templates: 3244** 3245** <ul> 3246** <li> ? 3247** <li> ?NNN 3248** <li> :VVV 3249** <li> @VVV 3250** <li> $VVV 3251** </ul> 3252** 3253** In the templates above, NNN represents an integer literal, 3254** and VVV represents an alphanumeric identifier.)^ ^The values of these 3255** parameters (also called "host parameter names" or "SQL parameters") 3256** can be set using the sqlite3_bind_*() routines defined here. 3257** 3258** ^The first argument to the sqlite3_bind_*() routines is always 3259** a pointer to the [sqlite3_stmt] object returned from 3260** [sqlite3_prepare_v2()] or its variants. 3261** 3262** ^The second argument is the index of the SQL parameter to be set. 3263** ^The leftmost SQL parameter has an index of 1. ^When the same named 3264** SQL parameter is used more than once, second and subsequent 3265** occurrences have the same index as the first occurrence. 3266** ^The index for named parameters can be looked up using the 3267** [sqlite3_bind_parameter_index()] API if desired. ^The index 3268** for "?NNN" parameters is the value of NNN. 3269** ^The NNN value must be between 1 and the [sqlite3_limit()] 3270** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3271** 3272** ^The third argument is the value to bind to the parameter. 3273** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3274** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3275** is ignored and the end result is the same as sqlite3_bind_null(). 3276** 3277** ^(In those routines that have a fourth argument, its value is the 3278** number of bytes in the parameter. To be clear: the value is the 3279** number of <u>bytes</u> in the value, not the number of characters.)^ 3280** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3281** is negative, then the length of the string is 3282** the number of bytes up to the first zero terminator. 3283** If the fourth parameter to sqlite3_bind_blob() is negative, then 3284** the behavior is undefined. 3285** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3286** or sqlite3_bind_text16() then that parameter must be the byte offset 3287** where the NUL terminator would occur assuming the string were NUL 3288** terminated. If any NUL characters occur at byte offsets less than 3289** the value of the fourth parameter then the resulting string value will 3290** contain embedded NULs. The result of expressions involving strings 3291** with embedded NULs is undefined. 3292** 3293** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 3294** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 3295** string after SQLite has finished with it. ^The destructor is called 3296** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(), 3297** sqlite3_bind_text(), or sqlite3_bind_text16() fails. 3298** ^If the fifth argument is 3299** the special value [SQLITE_STATIC], then SQLite assumes that the 3300** information is in static, unmanaged space and does not need to be freed. 3301** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3302** SQLite makes its own private copy of the data immediately, before 3303** the sqlite3_bind_*() routine returns. 3304** 3305** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3306** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3307** (just an integer to hold its size) while it is being processed. 3308** Zeroblobs are intended to serve as placeholders for BLOBs whose 3309** content is later written using 3310** [sqlite3_blob_open | incremental BLOB I/O] routines. 3311** ^A negative value for the zeroblob results in a zero-length BLOB. 3312** 3313** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3314** for the [prepared statement] or with a prepared statement for which 3315** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3316** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3317** routine is passed a [prepared statement] that has been finalized, the 3318** result is undefined and probably harmful. 3319** 3320** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3321** ^Unbound parameters are interpreted as NULL. 3322** 3323** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3324** [error code] if anything goes wrong. 3325** ^[SQLITE_RANGE] is returned if the parameter 3326** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3327** 3328** See also: [sqlite3_bind_parameter_count()], 3329** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3330*/ 3331int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3332int sqlite3_bind_double(sqlite3_stmt*, int, double); 3333int sqlite3_bind_int(sqlite3_stmt*, int, int); 3334int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3335int sqlite3_bind_null(sqlite3_stmt*, int); 3336int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 3337int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3338int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3339int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3340 3341/* 3342** CAPI3REF: Number Of SQL Parameters 3343** 3344** ^This routine can be used to find the number of [SQL parameters] 3345** in a [prepared statement]. SQL parameters are tokens of the 3346** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3347** placeholders for values that are [sqlite3_bind_blob | bound] 3348** to the parameters at a later time. 3349** 3350** ^(This routine actually returns the index of the largest (rightmost) 3351** parameter. For all forms except ?NNN, this will correspond to the 3352** number of unique parameters. If parameters of the ?NNN form are used, 3353** there may be gaps in the list.)^ 3354** 3355** See also: [sqlite3_bind_blob|sqlite3_bind()], 3356** [sqlite3_bind_parameter_name()], and 3357** [sqlite3_bind_parameter_index()]. 3358*/ 3359int sqlite3_bind_parameter_count(sqlite3_stmt*); 3360 3361/* 3362** CAPI3REF: Name Of A Host Parameter 3363** 3364** ^The sqlite3_bind_parameter_name(P,N) interface returns 3365** the name of the N-th [SQL parameter] in the [prepared statement] P. 3366** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3367** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3368** respectively. 3369** In other words, the initial ":" or "$" or "@" or "?" 3370** is included as part of the name.)^ 3371** ^Parameters of the form "?" without a following integer have no name 3372** and are referred to as "nameless" or "anonymous parameters". 3373** 3374** ^The first host parameter has an index of 1, not 0. 3375** 3376** ^If the value N is out of range or if the N-th parameter is 3377** nameless, then NULL is returned. ^The returned string is 3378** always in UTF-8 encoding even if the named parameter was 3379** originally specified as UTF-16 in [sqlite3_prepare16()] or 3380** [sqlite3_prepare16_v2()]. 3381** 3382** See also: [sqlite3_bind_blob|sqlite3_bind()], 3383** [sqlite3_bind_parameter_count()], and 3384** [sqlite3_bind_parameter_index()]. 3385*/ 3386const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3387 3388/* 3389** CAPI3REF: Index Of A Parameter With A Given Name 3390** 3391** ^Return the index of an SQL parameter given its name. ^The 3392** index value returned is suitable for use as the second 3393** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3394** is returned if no matching parameter is found. ^The parameter 3395** name must be given in UTF-8 even if the original statement 3396** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3397** 3398** See also: [sqlite3_bind_blob|sqlite3_bind()], 3399** [sqlite3_bind_parameter_count()], and 3400** [sqlite3_bind_parameter_index()]. 3401*/ 3402int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3403 3404/* 3405** CAPI3REF: Reset All Bindings On A Prepared Statement 3406** 3407** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3408** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3409** ^Use this routine to reset all host parameters to NULL. 3410*/ 3411int sqlite3_clear_bindings(sqlite3_stmt*); 3412 3413/* 3414** CAPI3REF: Number Of Columns In A Result Set 3415** 3416** ^Return the number of columns in the result set returned by the 3417** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3418** statement that does not return data (for example an [UPDATE]). 3419** 3420** See also: [sqlite3_data_count()] 3421*/ 3422int sqlite3_column_count(sqlite3_stmt *pStmt); 3423 3424/* 3425** CAPI3REF: Column Names In A Result Set 3426** 3427** ^These routines return the name assigned to a particular column 3428** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3429** interface returns a pointer to a zero-terminated UTF-8 string 3430** and sqlite3_column_name16() returns a pointer to a zero-terminated 3431** UTF-16 string. ^The first parameter is the [prepared statement] 3432** that implements the [SELECT] statement. ^The second parameter is the 3433** column number. ^The leftmost column is number 0. 3434** 3435** ^The returned string pointer is valid until either the [prepared statement] 3436** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3437** reprepared by the first call to [sqlite3_step()] for a particular run 3438** or until the next call to 3439** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3440** 3441** ^If sqlite3_malloc() fails during the processing of either routine 3442** (for example during a conversion from UTF-8 to UTF-16) then a 3443** NULL pointer is returned. 3444** 3445** ^The name of a result column is the value of the "AS" clause for 3446** that column, if there is an AS clause. If there is no AS clause 3447** then the name of the column is unspecified and may change from 3448** one release of SQLite to the next. 3449*/ 3450const char *sqlite3_column_name(sqlite3_stmt*, int N); 3451const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3452 3453/* 3454** CAPI3REF: Source Of Data In A Query Result 3455** 3456** ^These routines provide a means to determine the database, table, and 3457** table column that is the origin of a particular result column in 3458** [SELECT] statement. 3459** ^The name of the database or table or column can be returned as 3460** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3461** the database name, the _table_ routines return the table name, and 3462** the origin_ routines return the column name. 3463** ^The returned string is valid until the [prepared statement] is destroyed 3464** using [sqlite3_finalize()] or until the statement is automatically 3465** reprepared by the first call to [sqlite3_step()] for a particular run 3466** or until the same information is requested 3467** again in a different encoding. 3468** 3469** ^The names returned are the original un-aliased names of the 3470** database, table, and column. 3471** 3472** ^The first argument to these interfaces is a [prepared statement]. 3473** ^These functions return information about the Nth result column returned by 3474** the statement, where N is the second function argument. 3475** ^The left-most column is column 0 for these routines. 3476** 3477** ^If the Nth column returned by the statement is an expression or 3478** subquery and is not a column value, then all of these functions return 3479** NULL. ^These routine might also return NULL if a memory allocation error 3480** occurs. ^Otherwise, they return the name of the attached database, table, 3481** or column that query result column was extracted from. 3482** 3483** ^As with all other SQLite APIs, those whose names end with "16" return 3484** UTF-16 encoded strings and the other functions return UTF-8. 3485** 3486** ^These APIs are only available if the library was compiled with the 3487** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3488** 3489** If two or more threads call one or more of these routines against the same 3490** prepared statement and column at the same time then the results are 3491** undefined. 3492** 3493** If two or more threads call one or more 3494** [sqlite3_column_database_name | column metadata interfaces] 3495** for the same [prepared statement] and result column 3496** at the same time then the results are undefined. 3497*/ 3498const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3499const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3500const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3501const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3502const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3503const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3504 3505/* 3506** CAPI3REF: Declared Datatype Of A Query Result 3507** 3508** ^(The first parameter is a [prepared statement]. 3509** If this statement is a [SELECT] statement and the Nth column of the 3510** returned result set of that [SELECT] is a table column (not an 3511** expression or subquery) then the declared type of the table 3512** column is returned.)^ ^If the Nth column of the result set is an 3513** expression or subquery, then a NULL pointer is returned. 3514** ^The returned string is always UTF-8 encoded. 3515** 3516** ^(For example, given the database schema: 3517** 3518** CREATE TABLE t1(c1 VARIANT); 3519** 3520** and the following statement to be compiled: 3521** 3522** SELECT c1 + 1, c1 FROM t1; 3523** 3524** this routine would return the string "VARIANT" for the second result 3525** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3526** 3527** ^SQLite uses dynamic run-time typing. ^So just because a column 3528** is declared to contain a particular type does not mean that the 3529** data stored in that column is of the declared type. SQLite is 3530** strongly typed, but the typing is dynamic not static. ^Type 3531** is associated with individual values, not with the containers 3532** used to hold those values. 3533*/ 3534const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3535const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3536 3537/* 3538** CAPI3REF: Evaluate An SQL Statement 3539** 3540** After a [prepared statement] has been prepared using either 3541** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3542** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3543** must be called one or more times to evaluate the statement. 3544** 3545** The details of the behavior of the sqlite3_step() interface depend 3546** on whether the statement was prepared using the newer "v2" interface 3547** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3548** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3549** new "v2" interface is recommended for new applications but the legacy 3550** interface will continue to be supported. 3551** 3552** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3553** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3554** ^With the "v2" interface, any of the other [result codes] or 3555** [extended result codes] might be returned as well. 3556** 3557** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3558** database locks it needs to do its job. ^If the statement is a [COMMIT] 3559** or occurs outside of an explicit transaction, then you can retry the 3560** statement. If the statement is not a [COMMIT] and occurs within an 3561** explicit transaction then you should rollback the transaction before 3562** continuing. 3563** 3564** ^[SQLITE_DONE] means that the statement has finished executing 3565** successfully. sqlite3_step() should not be called again on this virtual 3566** machine without first calling [sqlite3_reset()] to reset the virtual 3567** machine back to its initial state. 3568** 3569** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3570** is returned each time a new row of data is ready for processing by the 3571** caller. The values may be accessed using the [column access functions]. 3572** sqlite3_step() is called again to retrieve the next row of data. 3573** 3574** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3575** violation) has occurred. sqlite3_step() should not be called again on 3576** the VM. More information may be found by calling [sqlite3_errmsg()]. 3577** ^With the legacy interface, a more specific error code (for example, 3578** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3579** can be obtained by calling [sqlite3_reset()] on the 3580** [prepared statement]. ^In the "v2" interface, 3581** the more specific error code is returned directly by sqlite3_step(). 3582** 3583** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3584** Perhaps it was called on a [prepared statement] that has 3585** already been [sqlite3_finalize | finalized] or on one that had 3586** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3587** be the case that the same database connection is being used by two or 3588** more threads at the same moment in time. 3589** 3590** For all versions of SQLite up to and including 3.6.23.1, a call to 3591** [sqlite3_reset()] was required after sqlite3_step() returned anything 3592** other than [SQLITE_ROW] before any subsequent invocation of 3593** sqlite3_step(). Failure to reset the prepared statement using 3594** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3595** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3596** calling [sqlite3_reset()] automatically in this circumstance rather 3597** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3598** break because any application that ever receives an SQLITE_MISUSE error 3599** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3600** can be used to restore the legacy behavior. 3601** 3602** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3603** API always returns a generic error code, [SQLITE_ERROR], following any 3604** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3605** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3606** specific [error codes] that better describes the error. 3607** We admit that this is a goofy design. The problem has been fixed 3608** with the "v2" interface. If you prepare all of your SQL statements 3609** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3610** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3611** then the more specific [error codes] are returned directly 3612** by sqlite3_step(). The use of the "v2" interface is recommended. 3613*/ 3614int sqlite3_step(sqlite3_stmt*); 3615 3616/* 3617** CAPI3REF: Number of columns in a result set 3618** 3619** ^The sqlite3_data_count(P) interface returns the number of columns in the 3620** current row of the result set of [prepared statement] P. 3621** ^If prepared statement P does not have results ready to return 3622** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3623** interfaces) then sqlite3_data_count(P) returns 0. 3624** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3625** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 3626** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 3627** will return non-zero if previous call to [sqlite3_step](P) returned 3628** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 3629** where it always returns zero since each step of that multi-step 3630** pragma returns 0 columns of data. 3631** 3632** See also: [sqlite3_column_count()] 3633*/ 3634int sqlite3_data_count(sqlite3_stmt *pStmt); 3635 3636/* 3637** CAPI3REF: Fundamental Datatypes 3638** KEYWORDS: SQLITE_TEXT 3639** 3640** ^(Every value in SQLite has one of five fundamental datatypes: 3641** 3642** <ul> 3643** <li> 64-bit signed integer 3644** <li> 64-bit IEEE floating point number 3645** <li> string 3646** <li> BLOB 3647** <li> NULL 3648** </ul>)^ 3649** 3650** These constants are codes for each of those types. 3651** 3652** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3653** for a completely different meaning. Software that links against both 3654** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3655** SQLITE_TEXT. 3656*/ 3657#define SQLITE_INTEGER 1 3658#define SQLITE_FLOAT 2 3659#define SQLITE_BLOB 4 3660#define SQLITE_NULL 5 3661#ifdef SQLITE_TEXT 3662# undef SQLITE_TEXT 3663#else 3664# define SQLITE_TEXT 3 3665#endif 3666#define SQLITE3_TEXT 3 3667 3668/* 3669** CAPI3REF: Result Values From A Query 3670** KEYWORDS: {column access functions} 3671** 3672** These routines form the "result set" interface. 3673** 3674** ^These routines return information about a single column of the current 3675** result row of a query. ^In every case the first argument is a pointer 3676** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3677** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3678** and the second argument is the index of the column for which information 3679** should be returned. ^The leftmost column of the result set has the index 0. 3680** ^The number of columns in the result can be determined using 3681** [sqlite3_column_count()]. 3682** 3683** If the SQL statement does not currently point to a valid row, or if the 3684** column index is out of range, the result is undefined. 3685** These routines may only be called when the most recent call to 3686** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3687** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3688** If any of these routines are called after [sqlite3_reset()] or 3689** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3690** something other than [SQLITE_ROW], the results are undefined. 3691** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3692** are called from a different thread while any of these routines 3693** are pending, then the results are undefined. 3694** 3695** ^The sqlite3_column_type() routine returns the 3696** [SQLITE_INTEGER | datatype code] for the initial data type 3697** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3698** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3699** returned by sqlite3_column_type() is only meaningful if no type 3700** conversions have occurred as described below. After a type conversion, 3701** the value returned by sqlite3_column_type() is undefined. Future 3702** versions of SQLite may change the behavior of sqlite3_column_type() 3703** following a type conversion. 3704** 3705** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3706** routine returns the number of bytes in that BLOB or string. 3707** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3708** the string to UTF-8 and then returns the number of bytes. 3709** ^If the result is a numeric value then sqlite3_column_bytes() uses 3710** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3711** the number of bytes in that string. 3712** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3713** 3714** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3715** routine returns the number of bytes in that BLOB or string. 3716** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3717** the string to UTF-16 and then returns the number of bytes. 3718** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3719** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3720** the number of bytes in that string. 3721** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3722** 3723** ^The values returned by [sqlite3_column_bytes()] and 3724** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3725** of the string. ^For clarity: the values returned by 3726** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3727** bytes in the string, not the number of characters. 3728** 3729** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3730** even empty strings, are always zero-terminated. ^The return 3731** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3732** 3733** ^The object returned by [sqlite3_column_value()] is an 3734** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3735** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3736** If the [unprotected sqlite3_value] object returned by 3737** [sqlite3_column_value()] is used in any other way, including calls 3738** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3739** or [sqlite3_value_bytes()], then the behavior is undefined. 3740** 3741** These routines attempt to convert the value where appropriate. ^For 3742** example, if the internal representation is FLOAT and a text result 3743** is requested, [sqlite3_snprintf()] is used internally to perform the 3744** conversion automatically. ^(The following table details the conversions 3745** that are applied: 3746** 3747** <blockquote> 3748** <table border="1"> 3749** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3750** 3751** <tr><td> NULL <td> INTEGER <td> Result is 0 3752** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3753** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3754** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3755** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3756** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3757** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3758** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3759** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3760** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3761** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3762** <tr><td> TEXT <td> FLOAT <td> Use atof() 3763** <tr><td> TEXT <td> BLOB <td> No change 3764** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3765** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3766** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3767** </table> 3768** </blockquote>)^ 3769** 3770** The table above makes reference to standard C library functions atoi() 3771** and atof(). SQLite does not really use these functions. It has its 3772** own equivalent internal routines. The atoi() and atof() names are 3773** used in the table for brevity and because they are familiar to most 3774** C programmers. 3775** 3776** Note that when type conversions occur, pointers returned by prior 3777** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3778** sqlite3_column_text16() may be invalidated. 3779** Type conversions and pointer invalidations might occur 3780** in the following cases: 3781** 3782** <ul> 3783** <li> The initial content is a BLOB and sqlite3_column_text() or 3784** sqlite3_column_text16() is called. A zero-terminator might 3785** need to be added to the string.</li> 3786** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3787** sqlite3_column_text16() is called. The content must be converted 3788** to UTF-16.</li> 3789** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3790** sqlite3_column_text() is called. The content must be converted 3791** to UTF-8.</li> 3792** </ul> 3793** 3794** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3795** not invalidate a prior pointer, though of course the content of the buffer 3796** that the prior pointer references will have been modified. Other kinds 3797** of conversion are done in place when it is possible, but sometimes they 3798** are not possible and in those cases prior pointers are invalidated. 3799** 3800** The safest and easiest to remember policy is to invoke these routines 3801** in one of the following ways: 3802** 3803** <ul> 3804** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3805** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3806** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3807** </ul> 3808** 3809** In other words, you should call sqlite3_column_text(), 3810** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3811** into the desired format, then invoke sqlite3_column_bytes() or 3812** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3813** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3814** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3815** with calls to sqlite3_column_bytes(). 3816** 3817** ^The pointers returned are valid until a type conversion occurs as 3818** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3819** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3820** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3821** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3822** [sqlite3_free()]. 3823** 3824** ^(If a memory allocation error occurs during the evaluation of any 3825** of these routines, a default value is returned. The default value 3826** is either the integer 0, the floating point number 0.0, or a NULL 3827** pointer. Subsequent calls to [sqlite3_errcode()] will return 3828** [SQLITE_NOMEM].)^ 3829*/ 3830const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3831int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3832int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3833double sqlite3_column_double(sqlite3_stmt*, int iCol); 3834int sqlite3_column_int(sqlite3_stmt*, int iCol); 3835sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3836const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3837const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3838int sqlite3_column_type(sqlite3_stmt*, int iCol); 3839sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3840 3841/* 3842** CAPI3REF: Destroy A Prepared Statement Object 3843** 3844** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3845** ^If the most recent evaluation of the statement encountered no errors 3846** or if the statement is never been evaluated, then sqlite3_finalize() returns 3847** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 3848** sqlite3_finalize(S) returns the appropriate [error code] or 3849** [extended error code]. 3850** 3851** ^The sqlite3_finalize(S) routine can be called at any point during 3852** the life cycle of [prepared statement] S: 3853** before statement S is ever evaluated, after 3854** one or more calls to [sqlite3_reset()], or after any call 3855** to [sqlite3_step()] regardless of whether or not the statement has 3856** completed execution. 3857** 3858** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 3859** 3860** The application must finalize every [prepared statement] in order to avoid 3861** resource leaks. It is a grievous error for the application to try to use 3862** a prepared statement after it has been finalized. Any use of a prepared 3863** statement after it has been finalized can result in undefined and 3864** undesirable behavior such as segfaults and heap corruption. 3865*/ 3866int sqlite3_finalize(sqlite3_stmt *pStmt); 3867 3868/* 3869** CAPI3REF: Reset A Prepared Statement Object 3870** 3871** The sqlite3_reset() function is called to reset a [prepared statement] 3872** object back to its initial state, ready to be re-executed. 3873** ^Any SQL statement variables that had values bound to them using 3874** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3875** Use [sqlite3_clear_bindings()] to reset the bindings. 3876** 3877** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3878** back to the beginning of its program. 3879** 3880** ^If the most recent call to [sqlite3_step(S)] for the 3881** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3882** or if [sqlite3_step(S)] has never before been called on S, 3883** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3884** 3885** ^If the most recent call to [sqlite3_step(S)] for the 3886** [prepared statement] S indicated an error, then 3887** [sqlite3_reset(S)] returns an appropriate [error code]. 3888** 3889** ^The [sqlite3_reset(S)] interface does not change the values 3890** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3891*/ 3892int sqlite3_reset(sqlite3_stmt *pStmt); 3893 3894/* 3895** CAPI3REF: Create Or Redefine SQL Functions 3896** KEYWORDS: {function creation routines} 3897** KEYWORDS: {application-defined SQL function} 3898** KEYWORDS: {application-defined SQL functions} 3899** 3900** ^These functions (collectively known as "function creation routines") 3901** are used to add SQL functions or aggregates or to redefine the behavior 3902** of existing SQL functions or aggregates. The only differences between 3903** these routines are the text encoding expected for 3904** the second parameter (the name of the function being created) 3905** and the presence or absence of a destructor callback for 3906** the application data pointer. 3907** 3908** ^The first parameter is the [database connection] to which the SQL 3909** function is to be added. ^If an application uses more than one database 3910** connection then application-defined SQL functions must be added 3911** to each database connection separately. 3912** 3913** ^The second parameter is the name of the SQL function to be created or 3914** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 3915** representation, exclusive of the zero-terminator. ^Note that the name 3916** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 3917** ^Any attempt to create a function with a longer name 3918** will result in [SQLITE_MISUSE] being returned. 3919** 3920** ^The third parameter (nArg) 3921** is the number of arguments that the SQL function or 3922** aggregate takes. ^If this parameter is -1, then the SQL function or 3923** aggregate may take any number of arguments between 0 and the limit 3924** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3925** parameter is less than -1 or greater than 127 then the behavior is 3926** undefined. 3927** 3928** ^The fourth parameter, eTextRep, specifies what 3929** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3930** its parameters. Every SQL function implementation must be able to work 3931** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3932** more efficient with one encoding than another. ^An application may 3933** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3934** times with the same function but with different values of eTextRep. 3935** ^When multiple implementations of the same function are available, SQLite 3936** will pick the one that involves the least amount of data conversion. 3937** If there is only a single implementation which does not care what text 3938** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3939** 3940** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3941** function can gain access to this pointer using [sqlite3_user_data()].)^ 3942** 3943** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 3944** pointers to C-language functions that implement the SQL function or 3945** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3946** callback only; NULL pointers must be passed as the xStep and xFinal 3947** parameters. ^An aggregate SQL function requires an implementation of xStep 3948** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 3949** SQL function or aggregate, pass NULL pointers for all three function 3950** callbacks. 3951** 3952** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 3953** then it is destructor for the application data pointer. 3954** The destructor is invoked when the function is deleted, either by being 3955** overloaded or when the database connection closes.)^ 3956** ^The destructor is also invoked if the call to 3957** sqlite3_create_function_v2() fails. 3958** ^When the destructor callback of the tenth parameter is invoked, it 3959** is passed a single argument which is a copy of the application data 3960** pointer which was the fifth parameter to sqlite3_create_function_v2(). 3961** 3962** ^It is permitted to register multiple implementations of the same 3963** functions with the same name but with either differing numbers of 3964** arguments or differing preferred text encodings. ^SQLite will use 3965** the implementation that most closely matches the way in which the 3966** SQL function is used. ^A function implementation with a non-negative 3967** nArg parameter is a better match than a function implementation with 3968** a negative nArg. ^A function where the preferred text encoding 3969** matches the database encoding is a better 3970** match than a function where the encoding is different. 3971** ^A function where the encoding difference is between UTF16le and UTF16be 3972** is a closer match than a function where the encoding difference is 3973** between UTF8 and UTF16. 3974** 3975** ^Built-in functions may be overloaded by new application-defined functions. 3976** 3977** ^An application-defined function is permitted to call other 3978** SQLite interfaces. However, such calls must not 3979** close the database connection nor finalize or reset the prepared 3980** statement in which the function is running. 3981*/ 3982int sqlite3_create_function( 3983 sqlite3 *db, 3984 const char *zFunctionName, 3985 int nArg, 3986 int eTextRep, 3987 void *pApp, 3988 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3989 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3990 void (*xFinal)(sqlite3_context*) 3991); 3992int sqlite3_create_function16( 3993 sqlite3 *db, 3994 const void *zFunctionName, 3995 int nArg, 3996 int eTextRep, 3997 void *pApp, 3998 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3999 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4000 void (*xFinal)(sqlite3_context*) 4001); 4002int sqlite3_create_function_v2( 4003 sqlite3 *db, 4004 const char *zFunctionName, 4005 int nArg, 4006 int eTextRep, 4007 void *pApp, 4008 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4009 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4010 void (*xFinal)(sqlite3_context*), 4011 void(*xDestroy)(void*) 4012); 4013 4014/* 4015** CAPI3REF: Text Encodings 4016** 4017** These constant define integer codes that represent the various 4018** text encodings supported by SQLite. 4019*/ 4020#define SQLITE_UTF8 1 4021#define SQLITE_UTF16LE 2 4022#define SQLITE_UTF16BE 3 4023#define SQLITE_UTF16 4 /* Use native byte order */ 4024#define SQLITE_ANY 5 /* sqlite3_create_function only */ 4025#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4026 4027/* 4028** CAPI3REF: Deprecated Functions 4029** DEPRECATED 4030** 4031** These functions are [deprecated]. In order to maintain 4032** backwards compatibility with older code, these functions continue 4033** to be supported. However, new applications should avoid 4034** the use of these functions. To help encourage people to avoid 4035** using these functions, we are not going to tell you what they do. 4036*/ 4037#ifndef SQLITE_OMIT_DEPRECATED 4038SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4039SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4040SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4041SQLITE_DEPRECATED int sqlite3_global_recover(void); 4042SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4043SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4044 void*,sqlite3_int64); 4045#endif 4046 4047/* 4048** CAPI3REF: Obtaining SQL Function Parameter Values 4049** 4050** The C-language implementation of SQL functions and aggregates uses 4051** this set of interface routines to access the parameter values on 4052** the function or aggregate. 4053** 4054** The xFunc (for scalar functions) or xStep (for aggregates) parameters 4055** to [sqlite3_create_function()] and [sqlite3_create_function16()] 4056** define callbacks that implement the SQL functions and aggregates. 4057** The 3rd parameter to these callbacks is an array of pointers to 4058** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 4059** each parameter to the SQL function. These routines are used to 4060** extract values from the [sqlite3_value] objects. 4061** 4062** These routines work only with [protected sqlite3_value] objects. 4063** Any attempt to use these routines on an [unprotected sqlite3_value] 4064** object results in undefined behavior. 4065** 4066** ^These routines work just like the corresponding [column access functions] 4067** except that these routines take a single [protected sqlite3_value] object 4068** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4069** 4070** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4071** in the native byte-order of the host machine. ^The 4072** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4073** extract UTF-16 strings as big-endian and little-endian respectively. 4074** 4075** ^(The sqlite3_value_numeric_type() interface attempts to apply 4076** numeric affinity to the value. This means that an attempt is 4077** made to convert the value to an integer or floating point. If 4078** such a conversion is possible without loss of information (in other 4079** words, if the value is a string that looks like a number) 4080** then the conversion is performed. Otherwise no conversion occurs. 4081** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4082** 4083** Please pay particular attention to the fact that the pointer returned 4084** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4085** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4086** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4087** or [sqlite3_value_text16()]. 4088** 4089** These routines must be called from the same thread as 4090** the SQL function that supplied the [sqlite3_value*] parameters. 4091*/ 4092const void *sqlite3_value_blob(sqlite3_value*); 4093int sqlite3_value_bytes(sqlite3_value*); 4094int sqlite3_value_bytes16(sqlite3_value*); 4095double sqlite3_value_double(sqlite3_value*); 4096int sqlite3_value_int(sqlite3_value*); 4097sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4098const unsigned char *sqlite3_value_text(sqlite3_value*); 4099const void *sqlite3_value_text16(sqlite3_value*); 4100const void *sqlite3_value_text16le(sqlite3_value*); 4101const void *sqlite3_value_text16be(sqlite3_value*); 4102int sqlite3_value_type(sqlite3_value*); 4103int sqlite3_value_numeric_type(sqlite3_value*); 4104 4105/* 4106** CAPI3REF: Obtain Aggregate Function Context 4107** 4108** Implementations of aggregate SQL functions use this 4109** routine to allocate memory for storing their state. 4110** 4111** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4112** for a particular aggregate function, SQLite 4113** allocates N of memory, zeroes out that memory, and returns a pointer 4114** to the new memory. ^On second and subsequent calls to 4115** sqlite3_aggregate_context() for the same aggregate function instance, 4116** the same buffer is returned. Sqlite3_aggregate_context() is normally 4117** called once for each invocation of the xStep callback and then one 4118** last time when the xFinal callback is invoked. ^(When no rows match 4119** an aggregate query, the xStep() callback of the aggregate function 4120** implementation is never called and xFinal() is called exactly once. 4121** In those cases, sqlite3_aggregate_context() might be called for the 4122** first time from within xFinal().)^ 4123** 4124** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4125** when first called if N is less than or equal to zero or if a memory 4126** allocate error occurs. 4127** 4128** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4129** determined by the N parameter on first successful call. Changing the 4130** value of N in subsequent call to sqlite3_aggregate_context() within 4131** the same aggregate function instance will not resize the memory 4132** allocation.)^ Within the xFinal callback, it is customary to set 4133** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4134** pointless memory allocations occur. 4135** 4136** ^SQLite automatically frees the memory allocated by 4137** sqlite3_aggregate_context() when the aggregate query concludes. 4138** 4139** The first parameter must be a copy of the 4140** [sqlite3_context | SQL function context] that is the first parameter 4141** to the xStep or xFinal callback routine that implements the aggregate 4142** function. 4143** 4144** This routine must be called from the same thread in which 4145** the aggregate SQL function is running. 4146*/ 4147void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4148 4149/* 4150** CAPI3REF: User Data For Functions 4151** 4152** ^The sqlite3_user_data() interface returns a copy of 4153** the pointer that was the pUserData parameter (the 5th parameter) 4154** of the [sqlite3_create_function()] 4155** and [sqlite3_create_function16()] routines that originally 4156** registered the application defined function. 4157** 4158** This routine must be called from the same thread in which 4159** the application-defined function is running. 4160*/ 4161void *sqlite3_user_data(sqlite3_context*); 4162 4163/* 4164** CAPI3REF: Database Connection For Functions 4165** 4166** ^The sqlite3_context_db_handle() interface returns a copy of 4167** the pointer to the [database connection] (the 1st parameter) 4168** of the [sqlite3_create_function()] 4169** and [sqlite3_create_function16()] routines that originally 4170** registered the application defined function. 4171*/ 4172sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4173 4174/* 4175** CAPI3REF: Function Auxiliary Data 4176** 4177** The following two functions may be used by scalar SQL functions to 4178** associate metadata with argument values. If the same value is passed to 4179** multiple invocations of the same SQL function during query execution, under 4180** some circumstances the associated metadata may be preserved. This may 4181** be used, for example, to add a regular-expression matching scalar 4182** function. The compiled version of the regular expression is stored as 4183** metadata associated with the SQL value passed as the regular expression 4184** pattern. The compiled regular expression can be reused on multiple 4185** invocations of the same function so that the original pattern string 4186** does not need to be recompiled on each invocation. 4187** 4188** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4189** associated by the sqlite3_set_auxdata() function with the Nth argument 4190** value to the application-defined function. ^If no metadata has been ever 4191** been set for the Nth argument of the function, or if the corresponding 4192** function parameter has changed since the meta-data was set, 4193** then sqlite3_get_auxdata() returns a NULL pointer. 4194** 4195** ^The sqlite3_set_auxdata() interface saves the metadata 4196** pointed to by its 3rd parameter as the metadata for the N-th 4197** argument of the application-defined function. Subsequent 4198** calls to sqlite3_get_auxdata() might return this data, if it has 4199** not been destroyed. 4200** ^If it is not NULL, SQLite will invoke the destructor 4201** function given by the 4th parameter to sqlite3_set_auxdata() on 4202** the metadata when the corresponding function parameter changes 4203** or when the SQL statement completes, whichever comes first. 4204** 4205** SQLite is free to call the destructor and drop metadata on any 4206** parameter of any function at any time. ^The only guarantee is that 4207** the destructor will be called before the metadata is dropped. 4208** 4209** ^(In practice, metadata is preserved between function calls for 4210** expressions that are constant at compile time. This includes literal 4211** values and [parameters].)^ 4212** 4213** These routines must be called from the same thread in which 4214** the SQL function is running. 4215*/ 4216void *sqlite3_get_auxdata(sqlite3_context*, int N); 4217void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4218 4219 4220/* 4221** CAPI3REF: Constants Defining Special Destructor Behavior 4222** 4223** These are special values for the destructor that is passed in as the 4224** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4225** argument is SQLITE_STATIC, it means that the content pointer is constant 4226** and will never change. It does not need to be destroyed. ^The 4227** SQLITE_TRANSIENT value means that the content will likely change in 4228** the near future and that SQLite should make its own private copy of 4229** the content before returning. 4230** 4231** The typedef is necessary to work around problems in certain 4232** C++ compilers. 4233*/ 4234typedef void (*sqlite3_destructor_type)(void*); 4235#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4236#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4237 4238/* 4239** CAPI3REF: Setting The Result Of An SQL Function 4240** 4241** These routines are used by the xFunc or xFinal callbacks that 4242** implement SQL functions and aggregates. See 4243** [sqlite3_create_function()] and [sqlite3_create_function16()] 4244** for additional information. 4245** 4246** These functions work very much like the [parameter binding] family of 4247** functions used to bind values to host parameters in prepared statements. 4248** Refer to the [SQL parameter] documentation for additional information. 4249** 4250** ^The sqlite3_result_blob() interface sets the result from 4251** an application-defined function to be the BLOB whose content is pointed 4252** to by the second parameter and which is N bytes long where N is the 4253** third parameter. 4254** 4255** ^The sqlite3_result_zeroblob() interfaces set the result of 4256** the application-defined function to be a BLOB containing all zero 4257** bytes and N bytes in size, where N is the value of the 2nd parameter. 4258** 4259** ^The sqlite3_result_double() interface sets the result from 4260** an application-defined function to be a floating point value specified 4261** by its 2nd argument. 4262** 4263** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4264** cause the implemented SQL function to throw an exception. 4265** ^SQLite uses the string pointed to by the 4266** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4267** as the text of an error message. ^SQLite interprets the error 4268** message string from sqlite3_result_error() as UTF-8. ^SQLite 4269** interprets the string from sqlite3_result_error16() as UTF-16 in native 4270** byte order. ^If the third parameter to sqlite3_result_error() 4271** or sqlite3_result_error16() is negative then SQLite takes as the error 4272** message all text up through the first zero character. 4273** ^If the third parameter to sqlite3_result_error() or 4274** sqlite3_result_error16() is non-negative then SQLite takes that many 4275** bytes (not characters) from the 2nd parameter as the error message. 4276** ^The sqlite3_result_error() and sqlite3_result_error16() 4277** routines make a private copy of the error message text before 4278** they return. Hence, the calling function can deallocate or 4279** modify the text after they return without harm. 4280** ^The sqlite3_result_error_code() function changes the error code 4281** returned by SQLite as a result of an error in a function. ^By default, 4282** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4283** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4284** 4285** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 4286** error indicating that a string or BLOB is too long to represent. 4287** 4288** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 4289** error indicating that a memory allocation failed. 4290** 4291** ^The sqlite3_result_int() interface sets the return value 4292** of the application-defined function to be the 32-bit signed integer 4293** value given in the 2nd argument. 4294** ^The sqlite3_result_int64() interface sets the return value 4295** of the application-defined function to be the 64-bit signed integer 4296** value given in the 2nd argument. 4297** 4298** ^The sqlite3_result_null() interface sets the return value 4299** of the application-defined function to be NULL. 4300** 4301** ^The sqlite3_result_text(), sqlite3_result_text16(), 4302** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4303** set the return value of the application-defined function to be 4304** a text string which is represented as UTF-8, UTF-16 native byte order, 4305** UTF-16 little endian, or UTF-16 big endian, respectively. 4306** ^SQLite takes the text result from the application from 4307** the 2nd parameter of the sqlite3_result_text* interfaces. 4308** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4309** is negative, then SQLite takes result text from the 2nd parameter 4310** through the first zero character. 4311** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4312** is non-negative, then as many bytes (not characters) of the text 4313** pointed to by the 2nd parameter are taken as the application-defined 4314** function result. If the 3rd parameter is non-negative, then it 4315** must be the byte offset into the string where the NUL terminator would 4316** appear if the string where NUL terminated. If any NUL characters occur 4317** in the string at a byte offset that is less than the value of the 3rd 4318** parameter, then the resulting string will contain embedded NULs and the 4319** result of expressions operating on strings with embedded NULs is undefined. 4320** ^If the 4th parameter to the sqlite3_result_text* interfaces 4321** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4322** function as the destructor on the text or BLOB result when it has 4323** finished using that result. 4324** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4325** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4326** assumes that the text or BLOB result is in constant space and does not 4327** copy the content of the parameter nor call a destructor on the content 4328** when it has finished using that result. 4329** ^If the 4th parameter to the sqlite3_result_text* interfaces 4330** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4331** then SQLite makes a copy of the result into space obtained from 4332** from [sqlite3_malloc()] before it returns. 4333** 4334** ^The sqlite3_result_value() interface sets the result of 4335** the application-defined function to be a copy the 4336** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4337** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4338** so that the [sqlite3_value] specified in the parameter may change or 4339** be deallocated after sqlite3_result_value() returns without harm. 4340** ^A [protected sqlite3_value] object may always be used where an 4341** [unprotected sqlite3_value] object is required, so either 4342** kind of [sqlite3_value] object can be used with this interface. 4343** 4344** If these routines are called from within the different thread 4345** than the one containing the application-defined function that received 4346** the [sqlite3_context] pointer, the results are undefined. 4347*/ 4348void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4349void sqlite3_result_double(sqlite3_context*, double); 4350void sqlite3_result_error(sqlite3_context*, const char*, int); 4351void sqlite3_result_error16(sqlite3_context*, const void*, int); 4352void sqlite3_result_error_toobig(sqlite3_context*); 4353void sqlite3_result_error_nomem(sqlite3_context*); 4354void sqlite3_result_error_code(sqlite3_context*, int); 4355void sqlite3_result_int(sqlite3_context*, int); 4356void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4357void sqlite3_result_null(sqlite3_context*); 4358void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4359void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4360void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4361void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4362void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4363void sqlite3_result_zeroblob(sqlite3_context*, int n); 4364 4365/* 4366** CAPI3REF: Define New Collating Sequences 4367** 4368** ^These functions add, remove, or modify a [collation] associated 4369** with the [database connection] specified as the first argument. 4370** 4371** ^The name of the collation is a UTF-8 string 4372** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4373** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4374** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4375** considered to be the same name. 4376** 4377** ^(The third argument (eTextRep) must be one of the constants: 4378** <ul> 4379** <li> [SQLITE_UTF8], 4380** <li> [SQLITE_UTF16LE], 4381** <li> [SQLITE_UTF16BE], 4382** <li> [SQLITE_UTF16], or 4383** <li> [SQLITE_UTF16_ALIGNED]. 4384** </ul>)^ 4385** ^The eTextRep argument determines the encoding of strings passed 4386** to the collating function callback, xCallback. 4387** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4388** force strings to be UTF16 with native byte order. 4389** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4390** on an even byte address. 4391** 4392** ^The fourth argument, pArg, is an application data pointer that is passed 4393** through as the first argument to the collating function callback. 4394** 4395** ^The fifth argument, xCallback, is a pointer to the collating function. 4396** ^Multiple collating functions can be registered using the same name but 4397** with different eTextRep parameters and SQLite will use whichever 4398** function requires the least amount of data transformation. 4399** ^If the xCallback argument is NULL then the collating function is 4400** deleted. ^When all collating functions having the same name are deleted, 4401** that collation is no longer usable. 4402** 4403** ^The collating function callback is invoked with a copy of the pArg 4404** application data pointer and with two strings in the encoding specified 4405** by the eTextRep argument. The collating function must return an 4406** integer that is negative, zero, or positive 4407** if the first string is less than, equal to, or greater than the second, 4408** respectively. A collating function must always return the same answer 4409** given the same inputs. If two or more collating functions are registered 4410** to the same collation name (using different eTextRep values) then all 4411** must give an equivalent answer when invoked with equivalent strings. 4412** The collating function must obey the following properties for all 4413** strings A, B, and C: 4414** 4415** <ol> 4416** <li> If A==B then B==A. 4417** <li> If A==B and B==C then A==C. 4418** <li> If A<B THEN B>A. 4419** <li> If A<B and B<C then A<C. 4420** </ol> 4421** 4422** If a collating function fails any of the above constraints and that 4423** collating function is registered and used, then the behavior of SQLite 4424** is undefined. 4425** 4426** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4427** with the addition that the xDestroy callback is invoked on pArg when 4428** the collating function is deleted. 4429** ^Collating functions are deleted when they are overridden by later 4430** calls to the collation creation functions or when the 4431** [database connection] is closed using [sqlite3_close()]. 4432** 4433** ^The xDestroy callback is <u>not</u> called if the 4434** sqlite3_create_collation_v2() function fails. Applications that invoke 4435** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4436** check the return code and dispose of the application data pointer 4437** themselves rather than expecting SQLite to deal with it for them. 4438** This is different from every other SQLite interface. The inconsistency 4439** is unfortunate but cannot be changed without breaking backwards 4440** compatibility. 4441** 4442** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4443*/ 4444int sqlite3_create_collation( 4445 sqlite3*, 4446 const char *zName, 4447 int eTextRep, 4448 void *pArg, 4449 int(*xCompare)(void*,int,const void*,int,const void*) 4450); 4451int sqlite3_create_collation_v2( 4452 sqlite3*, 4453 const char *zName, 4454 int eTextRep, 4455 void *pArg, 4456 int(*xCompare)(void*,int,const void*,int,const void*), 4457 void(*xDestroy)(void*) 4458); 4459int sqlite3_create_collation16( 4460 sqlite3*, 4461 const void *zName, 4462 int eTextRep, 4463 void *pArg, 4464 int(*xCompare)(void*,int,const void*,int,const void*) 4465); 4466 4467/* 4468** CAPI3REF: Collation Needed Callbacks 4469** 4470** ^To avoid having to register all collation sequences before a database 4471** can be used, a single callback function may be registered with the 4472** [database connection] to be invoked whenever an undefined collation 4473** sequence is required. 4474** 4475** ^If the function is registered using the sqlite3_collation_needed() API, 4476** then it is passed the names of undefined collation sequences as strings 4477** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4478** the names are passed as UTF-16 in machine native byte order. 4479** ^A call to either function replaces the existing collation-needed callback. 4480** 4481** ^(When the callback is invoked, the first argument passed is a copy 4482** of the second argument to sqlite3_collation_needed() or 4483** sqlite3_collation_needed16(). The second argument is the database 4484** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4485** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4486** sequence function required. The fourth parameter is the name of the 4487** required collation sequence.)^ 4488** 4489** The callback function should register the desired collation using 4490** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4491** [sqlite3_create_collation_v2()]. 4492*/ 4493int sqlite3_collation_needed( 4494 sqlite3*, 4495 void*, 4496 void(*)(void*,sqlite3*,int eTextRep,const char*) 4497); 4498int sqlite3_collation_needed16( 4499 sqlite3*, 4500 void*, 4501 void(*)(void*,sqlite3*,int eTextRep,const void*) 4502); 4503 4504#ifdef SQLITE_HAS_CODEC 4505/* 4506** Specify the key for an encrypted database. This routine should be 4507** called right after sqlite3_open(). 4508** 4509** The code to implement this API is not available in the public release 4510** of SQLite. 4511*/ 4512int sqlite3_key( 4513 sqlite3 *db, /* Database to be rekeyed */ 4514 const void *pKey, int nKey /* The key */ 4515); 4516 4517/* 4518** Change the key on an open database. If the current database is not 4519** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4520** database is decrypted. 4521** 4522** The code to implement this API is not available in the public release 4523** of SQLite. 4524*/ 4525int sqlite3_rekey( 4526 sqlite3 *db, /* Database to be rekeyed */ 4527 const void *pKey, int nKey /* The new key */ 4528); 4529 4530/* 4531** Specify the activation key for a SEE database. Unless 4532** activated, none of the SEE routines will work. 4533*/ 4534void sqlite3_activate_see( 4535 const char *zPassPhrase /* Activation phrase */ 4536); 4537#endif 4538 4539#ifdef SQLITE_ENABLE_CEROD 4540/* 4541** Specify the activation key for a CEROD database. Unless 4542** activated, none of the CEROD routines will work. 4543*/ 4544void sqlite3_activate_cerod( 4545 const char *zPassPhrase /* Activation phrase */ 4546); 4547#endif 4548 4549/* 4550** CAPI3REF: Suspend Execution For A Short Time 4551** 4552** The sqlite3_sleep() function causes the current thread to suspend execution 4553** for at least a number of milliseconds specified in its parameter. 4554** 4555** If the operating system does not support sleep requests with 4556** millisecond time resolution, then the time will be rounded up to 4557** the nearest second. The number of milliseconds of sleep actually 4558** requested from the operating system is returned. 4559** 4560** ^SQLite implements this interface by calling the xSleep() 4561** method of the default [sqlite3_vfs] object. If the xSleep() method 4562** of the default VFS is not implemented correctly, or not implemented at 4563** all, then the behavior of sqlite3_sleep() may deviate from the description 4564** in the previous paragraphs. 4565*/ 4566int sqlite3_sleep(int); 4567 4568/* 4569** CAPI3REF: Name Of The Folder Holding Temporary Files 4570** 4571** ^(If this global variable is made to point to a string which is 4572** the name of a folder (a.k.a. directory), then all temporary files 4573** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4574** will be placed in that directory.)^ ^If this variable 4575** is a NULL pointer, then SQLite performs a search for an appropriate 4576** temporary file directory. 4577** 4578** It is not safe to read or modify this variable in more than one 4579** thread at a time. It is not safe to read or modify this variable 4580** if a [database connection] is being used at the same time in a separate 4581** thread. 4582** It is intended that this variable be set once 4583** as part of process initialization and before any SQLite interface 4584** routines have been called and that this variable remain unchanged 4585** thereafter. 4586** 4587** ^The [temp_store_directory pragma] may modify this variable and cause 4588** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4589** the [temp_store_directory pragma] always assumes that any string 4590** that this variable points to is held in memory obtained from 4591** [sqlite3_malloc] and the pragma may attempt to free that memory 4592** using [sqlite3_free]. 4593** Hence, if this variable is modified directly, either it should be 4594** made NULL or made to point to memory obtained from [sqlite3_malloc] 4595** or else the use of the [temp_store_directory pragma] should be avoided. 4596** 4597** <b>Note to Windows Runtime users:</b> The temporary directory must be set 4598** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 4599** features that require the use of temporary files may fail. Here is an 4600** example of how to do this using C++ with the Windows Runtime: 4601** 4602** <blockquote><pre> 4603** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 4604** TemporaryFolder->Path->Data(); 4605** char zPathBuf[MAX_PATH + 1]; 4606** memset(zPathBuf, 0, sizeof(zPathBuf)); 4607** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 4608** NULL, NULL); 4609** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 4610** </pre></blockquote> 4611*/ 4612SQLITE_EXTERN char *sqlite3_temp_directory; 4613 4614/* 4615** CAPI3REF: Name Of The Folder Holding Database Files 4616** 4617** ^(If this global variable is made to point to a string which is 4618** the name of a folder (a.k.a. directory), then all database files 4619** specified with a relative pathname and created or accessed by 4620** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 4621** to be relative to that directory.)^ ^If this variable is a NULL 4622** pointer, then SQLite assumes that all database files specified 4623** with a relative pathname are relative to the current directory 4624** for the process. Only the windows VFS makes use of this global 4625** variable; it is ignored by the unix VFS. 4626** 4627** Changing the value of this variable while a database connection is 4628** open can result in a corrupt database. 4629** 4630** It is not safe to read or modify this variable in more than one 4631** thread at a time. It is not safe to read or modify this variable 4632** if a [database connection] is being used at the same time in a separate 4633** thread. 4634** It is intended that this variable be set once 4635** as part of process initialization and before any SQLite interface 4636** routines have been called and that this variable remain unchanged 4637** thereafter. 4638** 4639** ^The [data_store_directory pragma] may modify this variable and cause 4640** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4641** the [data_store_directory pragma] always assumes that any string 4642** that this variable points to is held in memory obtained from 4643** [sqlite3_malloc] and the pragma may attempt to free that memory 4644** using [sqlite3_free]. 4645** Hence, if this variable is modified directly, either it should be 4646** made NULL or made to point to memory obtained from [sqlite3_malloc] 4647** or else the use of the [data_store_directory pragma] should be avoided. 4648*/ 4649SQLITE_EXTERN char *sqlite3_data_directory; 4650 4651/* 4652** CAPI3REF: Test For Auto-Commit Mode 4653** KEYWORDS: {autocommit mode} 4654** 4655** ^The sqlite3_get_autocommit() interface returns non-zero or 4656** zero if the given database connection is or is not in autocommit mode, 4657** respectively. ^Autocommit mode is on by default. 4658** ^Autocommit mode is disabled by a [BEGIN] statement. 4659** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 4660** 4661** If certain kinds of errors occur on a statement within a multi-statement 4662** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 4663** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 4664** transaction might be rolled back automatically. The only way to 4665** find out whether SQLite automatically rolled back the transaction after 4666** an error is to use this function. 4667** 4668** If another thread changes the autocommit status of the database 4669** connection while this routine is running, then the return value 4670** is undefined. 4671*/ 4672int sqlite3_get_autocommit(sqlite3*); 4673 4674/* 4675** CAPI3REF: Find The Database Handle Of A Prepared Statement 4676** 4677** ^The sqlite3_db_handle interface returns the [database connection] handle 4678** to which a [prepared statement] belongs. ^The [database connection] 4679** returned by sqlite3_db_handle is the same [database connection] 4680** that was the first argument 4681** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 4682** create the statement in the first place. 4683*/ 4684sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 4685 4686/* 4687** CAPI3REF: Return The Filename For A Database Connection 4688** 4689** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 4690** associated with database N of connection D. ^The main database file 4691** has the name "main". If there is no attached database N on the database 4692** connection D, or if database N is a temporary or in-memory database, then 4693** a NULL pointer is returned. 4694** 4695** ^The filename returned by this function is the output of the 4696** xFullPathname method of the [VFS]. ^In other words, the filename 4697** will be an absolute pathname, even if the filename used 4698** to open the database originally was a URI or relative pathname. 4699*/ 4700const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 4701 4702/* 4703** CAPI3REF: Determine if a database is read-only 4704** 4705** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 4706** of connection D is read-only, 0 if it is read/write, or -1 if N is not 4707** the name of a database on connection D. 4708*/ 4709int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 4710 4711/* 4712** CAPI3REF: Find the next prepared statement 4713** 4714** ^This interface returns a pointer to the next [prepared statement] after 4715** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 4716** then this interface returns a pointer to the first prepared statement 4717** associated with the database connection pDb. ^If no prepared statement 4718** satisfies the conditions of this routine, it returns NULL. 4719** 4720** The [database connection] pointer D in a call to 4721** [sqlite3_next_stmt(D,S)] must refer to an open database 4722** connection and in particular must not be a NULL pointer. 4723*/ 4724sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 4725 4726/* 4727** CAPI3REF: Commit And Rollback Notification Callbacks 4728** 4729** ^The sqlite3_commit_hook() interface registers a callback 4730** function to be invoked whenever a transaction is [COMMIT | committed]. 4731** ^Any callback set by a previous call to sqlite3_commit_hook() 4732** for the same database connection is overridden. 4733** ^The sqlite3_rollback_hook() interface registers a callback 4734** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 4735** ^Any callback set by a previous call to sqlite3_rollback_hook() 4736** for the same database connection is overridden. 4737** ^The pArg argument is passed through to the callback. 4738** ^If the callback on a commit hook function returns non-zero, 4739** then the commit is converted into a rollback. 4740** 4741** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 4742** return the P argument from the previous call of the same function 4743** on the same [database connection] D, or NULL for 4744** the first call for each function on D. 4745** 4746** The commit and rollback hook callbacks are not reentrant. 4747** The callback implementation must not do anything that will modify 4748** the database connection that invoked the callback. Any actions 4749** to modify the database connection must be deferred until after the 4750** completion of the [sqlite3_step()] call that triggered the commit 4751** or rollback hook in the first place. 4752** Note that running any other SQL statements, including SELECT statements, 4753** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 4754** the database connections for the meaning of "modify" in this paragraph. 4755** 4756** ^Registering a NULL function disables the callback. 4757** 4758** ^When the commit hook callback routine returns zero, the [COMMIT] 4759** operation is allowed to continue normally. ^If the commit hook 4760** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 4761** ^The rollback hook is invoked on a rollback that results from a commit 4762** hook returning non-zero, just as it would be with any other rollback. 4763** 4764** ^For the purposes of this API, a transaction is said to have been 4765** rolled back if an explicit "ROLLBACK" statement is executed, or 4766** an error or constraint causes an implicit rollback to occur. 4767** ^The rollback callback is not invoked if a transaction is 4768** automatically rolled back because the database connection is closed. 4769** 4770** See also the [sqlite3_update_hook()] interface. 4771*/ 4772void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 4773void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 4774 4775/* 4776** CAPI3REF: Data Change Notification Callbacks 4777** 4778** ^The sqlite3_update_hook() interface registers a callback function 4779** with the [database connection] identified by the first argument 4780** to be invoked whenever a row is updated, inserted or deleted. 4781** ^Any callback set by a previous call to this function 4782** for the same database connection is overridden. 4783** 4784** ^The second argument is a pointer to the function to invoke when a 4785** row is updated, inserted or deleted. 4786** ^The first argument to the callback is a copy of the third argument 4787** to sqlite3_update_hook(). 4788** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 4789** or [SQLITE_UPDATE], depending on the operation that caused the callback 4790** to be invoked. 4791** ^The third and fourth arguments to the callback contain pointers to the 4792** database and table name containing the affected row. 4793** ^The final callback parameter is the [rowid] of the row. 4794** ^In the case of an update, this is the [rowid] after the update takes place. 4795** 4796** ^(The update hook is not invoked when internal system tables are 4797** modified (i.e. sqlite_master and sqlite_sequence).)^ 4798** 4799** ^In the current implementation, the update hook 4800** is not invoked when duplication rows are deleted because of an 4801** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 4802** invoked when rows are deleted using the [truncate optimization]. 4803** The exceptions defined in this paragraph might change in a future 4804** release of SQLite. 4805** 4806** The update hook implementation must not do anything that will modify 4807** the database connection that invoked the update hook. Any actions 4808** to modify the database connection must be deferred until after the 4809** completion of the [sqlite3_step()] call that triggered the update hook. 4810** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4811** database connections for the meaning of "modify" in this paragraph. 4812** 4813** ^The sqlite3_update_hook(D,C,P) function 4814** returns the P argument from the previous call 4815** on the same [database connection] D, or NULL for 4816** the first call on D. 4817** 4818** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4819** interfaces. 4820*/ 4821void *sqlite3_update_hook( 4822 sqlite3*, 4823 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4824 void* 4825); 4826 4827/* 4828** CAPI3REF: Enable Or Disable Shared Pager Cache 4829** 4830** ^(This routine enables or disables the sharing of the database cache 4831** and schema data structures between [database connection | connections] 4832** to the same database. Sharing is enabled if the argument is true 4833** and disabled if the argument is false.)^ 4834** 4835** ^Cache sharing is enabled and disabled for an entire process. 4836** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4837** sharing was enabled or disabled for each thread separately. 4838** 4839** ^(The cache sharing mode set by this interface effects all subsequent 4840** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4841** Existing database connections continue use the sharing mode 4842** that was in effect at the time they were opened.)^ 4843** 4844** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4845** successfully. An [error code] is returned otherwise.)^ 4846** 4847** ^Shared cache is disabled by default. But this might change in 4848** future releases of SQLite. Applications that care about shared 4849** cache setting should set it explicitly. 4850** 4851** This interface is threadsafe on processors where writing a 4852** 32-bit integer is atomic. 4853** 4854** See Also: [SQLite Shared-Cache Mode] 4855*/ 4856int sqlite3_enable_shared_cache(int); 4857 4858/* 4859** CAPI3REF: Attempt To Free Heap Memory 4860** 4861** ^The sqlite3_release_memory() interface attempts to free N bytes 4862** of heap memory by deallocating non-essential memory allocations 4863** held by the database library. Memory used to cache database 4864** pages to improve performance is an example of non-essential memory. 4865** ^sqlite3_release_memory() returns the number of bytes actually freed, 4866** which might be more or less than the amount requested. 4867** ^The sqlite3_release_memory() routine is a no-op returning zero 4868** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4869** 4870** See also: [sqlite3_db_release_memory()] 4871*/ 4872int sqlite3_release_memory(int); 4873 4874/* 4875** CAPI3REF: Free Memory Used By A Database Connection 4876** 4877** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 4878** memory as possible from database connection D. Unlike the 4879** [sqlite3_release_memory()] interface, this interface is effect even 4880** when then [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 4881** omitted. 4882** 4883** See also: [sqlite3_release_memory()] 4884*/ 4885int sqlite3_db_release_memory(sqlite3*); 4886 4887/* 4888** CAPI3REF: Impose A Limit On Heap Size 4889** 4890** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 4891** soft limit on the amount of heap memory that may be allocated by SQLite. 4892** ^SQLite strives to keep heap memory utilization below the soft heap 4893** limit by reducing the number of pages held in the page cache 4894** as heap memory usages approaches the limit. 4895** ^The soft heap limit is "soft" because even though SQLite strives to stay 4896** below the limit, it will exceed the limit rather than generate 4897** an [SQLITE_NOMEM] error. In other words, the soft heap limit 4898** is advisory only. 4899** 4900** ^The return value from sqlite3_soft_heap_limit64() is the size of 4901** the soft heap limit prior to the call, or negative in the case of an 4902** error. ^If the argument N is negative 4903** then no change is made to the soft heap limit. Hence, the current 4904** size of the soft heap limit can be determined by invoking 4905** sqlite3_soft_heap_limit64() with a negative argument. 4906** 4907** ^If the argument N is zero then the soft heap limit is disabled. 4908** 4909** ^(The soft heap limit is not enforced in the current implementation 4910** if one or more of following conditions are true: 4911** 4912** <ul> 4913** <li> The soft heap limit is set to zero. 4914** <li> Memory accounting is disabled using a combination of the 4915** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 4916** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 4917** <li> An alternative page cache implementation is specified using 4918** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 4919** <li> The page cache allocates from its own memory pool supplied 4920** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 4921** from the heap. 4922** </ul>)^ 4923** 4924** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 4925** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 4926** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 4927** the soft heap limit is enforced on every memory allocation. Without 4928** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 4929** when memory is allocated by the page cache. Testing suggests that because 4930** the page cache is the predominate memory user in SQLite, most 4931** applications will achieve adequate soft heap limit enforcement without 4932** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4933** 4934** The circumstances under which SQLite will enforce the soft heap limit may 4935** changes in future releases of SQLite. 4936*/ 4937sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 4938 4939/* 4940** CAPI3REF: Deprecated Soft Heap Limit Interface 4941** DEPRECATED 4942** 4943** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 4944** interface. This routine is provided for historical compatibility 4945** only. All new applications should use the 4946** [sqlite3_soft_heap_limit64()] interface rather than this one. 4947*/ 4948SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 4949 4950 4951/* 4952** CAPI3REF: Extract Metadata About A Column Of A Table 4953** 4954** ^This routine returns metadata about a specific column of a specific 4955** database table accessible using the [database connection] handle 4956** passed as the first function argument. 4957** 4958** ^The column is identified by the second, third and fourth parameters to 4959** this function. ^The second parameter is either the name of the database 4960** (i.e. "main", "temp", or an attached database) containing the specified 4961** table or NULL. ^If it is NULL, then all attached databases are searched 4962** for the table using the same algorithm used by the database engine to 4963** resolve unqualified table references. 4964** 4965** ^The third and fourth parameters to this function are the table and column 4966** name of the desired column, respectively. Neither of these parameters 4967** may be NULL. 4968** 4969** ^Metadata is returned by writing to the memory locations passed as the 5th 4970** and subsequent parameters to this function. ^Any of these arguments may be 4971** NULL, in which case the corresponding element of metadata is omitted. 4972** 4973** ^(<blockquote> 4974** <table border="1"> 4975** <tr><th> Parameter <th> Output<br>Type <th> Description 4976** 4977** <tr><td> 5th <td> const char* <td> Data type 4978** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4979** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4980** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4981** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4982** </table> 4983** </blockquote>)^ 4984** 4985** ^The memory pointed to by the character pointers returned for the 4986** declaration type and collation sequence is valid only until the next 4987** call to any SQLite API function. 4988** 4989** ^If the specified table is actually a view, an [error code] is returned. 4990** 4991** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4992** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4993** parameters are set for the explicitly declared column. ^(If there is no 4994** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4995** parameters are set as follows: 4996** 4997** <pre> 4998** data type: "INTEGER" 4999** collation sequence: "BINARY" 5000** not null: 0 5001** primary key: 1 5002** auto increment: 0 5003** </pre>)^ 5004** 5005** ^(This function may load one or more schemas from database files. If an 5006** error occurs during this process, or if the requested table or column 5007** cannot be found, an [error code] is returned and an error message left 5008** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 5009** 5010** ^This API is only available if the library was compiled with the 5011** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 5012*/ 5013int sqlite3_table_column_metadata( 5014 sqlite3 *db, /* Connection handle */ 5015 const char *zDbName, /* Database name or NULL */ 5016 const char *zTableName, /* Table name */ 5017 const char *zColumnName, /* Column name */ 5018 char const **pzDataType, /* OUTPUT: Declared data type */ 5019 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5020 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5021 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5022 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5023); 5024 5025/* 5026** CAPI3REF: Load An Extension 5027** 5028** ^This interface loads an SQLite extension library from the named file. 5029** 5030** ^The sqlite3_load_extension() interface attempts to load an 5031** [SQLite extension] library contained in the file zFile. If 5032** the file cannot be loaded directly, attempts are made to load 5033** with various operating-system specific extensions added. 5034** So for example, if "samplelib" cannot be loaded, then names like 5035** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5036** be tried also. 5037** 5038** ^The entry point is zProc. 5039** ^(zProc may be 0, in which case SQLite will try to come up with an 5040** entry point name on its own. It first tries "sqlite3_extension_init". 5041** If that does not work, it constructs a name "sqlite3_X_init" where the 5042** X is consists of the lower-case equivalent of all ASCII alphabetic 5043** characters in the filename from the last "/" to the first following 5044** "." and omitting any initial "lib".)^ 5045** ^The sqlite3_load_extension() interface returns 5046** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5047** ^If an error occurs and pzErrMsg is not 0, then the 5048** [sqlite3_load_extension()] interface shall attempt to 5049** fill *pzErrMsg with error message text stored in memory 5050** obtained from [sqlite3_malloc()]. The calling function 5051** should free this memory by calling [sqlite3_free()]. 5052** 5053** ^Extension loading must be enabled using 5054** [sqlite3_enable_load_extension()] prior to calling this API, 5055** otherwise an error will be returned. 5056** 5057** See also the [load_extension() SQL function]. 5058*/ 5059int sqlite3_load_extension( 5060 sqlite3 *db, /* Load the extension into this database connection */ 5061 const char *zFile, /* Name of the shared library containing extension */ 5062 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5063 char **pzErrMsg /* Put error message here if not 0 */ 5064); 5065 5066/* 5067** CAPI3REF: Enable Or Disable Extension Loading 5068** 5069** ^So as not to open security holes in older applications that are 5070** unprepared to deal with [extension loading], and as a means of disabling 5071** [extension loading] while evaluating user-entered SQL, the following API 5072** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5073** 5074** ^Extension loading is off by default. 5075** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5076** to turn extension loading on and call it with onoff==0 to turn 5077** it back off again. 5078*/ 5079int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5080 5081/* 5082** CAPI3REF: Automatically Load Statically Linked Extensions 5083** 5084** ^This interface causes the xEntryPoint() function to be invoked for 5085** each new [database connection] that is created. The idea here is that 5086** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5087** that is to be automatically loaded into all new database connections. 5088** 5089** ^(Even though the function prototype shows that xEntryPoint() takes 5090** no arguments and returns void, SQLite invokes xEntryPoint() with three 5091** arguments and expects and integer result as if the signature of the 5092** entry point where as follows: 5093** 5094** <blockquote><pre> 5095** int xEntryPoint( 5096** sqlite3 *db, 5097** const char **pzErrMsg, 5098** const struct sqlite3_api_routines *pThunk 5099** ); 5100** </pre></blockquote>)^ 5101** 5102** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5103** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5104** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5105** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5106** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5107** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5108** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 5109** 5110** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 5111** on the list of automatic extensions is a harmless no-op. ^No entry point 5112** will be called more than once for each database connection that is opened. 5113** 5114** See also: [sqlite3_reset_auto_extension()]. 5115*/ 5116int sqlite3_auto_extension(void (*xEntryPoint)(void)); 5117 5118/* 5119** CAPI3REF: Reset Automatic Extension Loading 5120** 5121** ^This interface disables all automatic extensions previously 5122** registered using [sqlite3_auto_extension()]. 5123*/ 5124void sqlite3_reset_auto_extension(void); 5125 5126/* 5127** The interface to the virtual-table mechanism is currently considered 5128** to be experimental. The interface might change in incompatible ways. 5129** If this is a problem for you, do not use the interface at this time. 5130** 5131** When the virtual-table mechanism stabilizes, we will declare the 5132** interface fixed, support it indefinitely, and remove this comment. 5133*/ 5134 5135/* 5136** Structures used by the virtual table interface 5137*/ 5138typedef struct sqlite3_vtab sqlite3_vtab; 5139typedef struct sqlite3_index_info sqlite3_index_info; 5140typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 5141typedef struct sqlite3_module sqlite3_module; 5142 5143/* 5144** CAPI3REF: Virtual Table Object 5145** KEYWORDS: sqlite3_module {virtual table module} 5146** 5147** This structure, sometimes called a "virtual table module", 5148** defines the implementation of a [virtual tables]. 5149** This structure consists mostly of methods for the module. 5150** 5151** ^A virtual table module is created by filling in a persistent 5152** instance of this structure and passing a pointer to that instance 5153** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 5154** ^The registration remains valid until it is replaced by a different 5155** module or until the [database connection] closes. The content 5156** of this structure must not change while it is registered with 5157** any database connection. 5158*/ 5159struct sqlite3_module { 5160 int iVersion; 5161 int (*xCreate)(sqlite3*, void *pAux, 5162 int argc, const char *const*argv, 5163 sqlite3_vtab **ppVTab, char**); 5164 int (*xConnect)(sqlite3*, void *pAux, 5165 int argc, const char *const*argv, 5166 sqlite3_vtab **ppVTab, char**); 5167 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 5168 int (*xDisconnect)(sqlite3_vtab *pVTab); 5169 int (*xDestroy)(sqlite3_vtab *pVTab); 5170 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 5171 int (*xClose)(sqlite3_vtab_cursor*); 5172 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 5173 int argc, sqlite3_value **argv); 5174 int (*xNext)(sqlite3_vtab_cursor*); 5175 int (*xEof)(sqlite3_vtab_cursor*); 5176 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 5177 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 5178 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 5179 int (*xBegin)(sqlite3_vtab *pVTab); 5180 int (*xSync)(sqlite3_vtab *pVTab); 5181 int (*xCommit)(sqlite3_vtab *pVTab); 5182 int (*xRollback)(sqlite3_vtab *pVTab); 5183 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 5184 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 5185 void **ppArg); 5186 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 5187 /* The methods above are in version 1 of the sqlite_module object. Those 5188 ** below are for version 2 and greater. */ 5189 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 5190 int (*xRelease)(sqlite3_vtab *pVTab, int); 5191 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 5192}; 5193 5194/* 5195** CAPI3REF: Virtual Table Indexing Information 5196** KEYWORDS: sqlite3_index_info 5197** 5198** The sqlite3_index_info structure and its substructures is used as part 5199** of the [virtual table] interface to 5200** pass information into and receive the reply from the [xBestIndex] 5201** method of a [virtual table module]. The fields under **Inputs** are the 5202** inputs to xBestIndex and are read-only. xBestIndex inserts its 5203** results into the **Outputs** fields. 5204** 5205** ^(The aConstraint[] array records WHERE clause constraints of the form: 5206** 5207** <blockquote>column OP expr</blockquote> 5208** 5209** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 5210** stored in aConstraint[].op using one of the 5211** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 5212** ^(The index of the column is stored in 5213** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5214** expr on the right-hand side can be evaluated (and thus the constraint 5215** is usable) and false if it cannot.)^ 5216** 5217** ^The optimizer automatically inverts terms of the form "expr OP column" 5218** and makes other simplifications to the WHERE clause in an attempt to 5219** get as many WHERE clause terms into the form shown above as possible. 5220** ^The aConstraint[] array only reports WHERE clause terms that are 5221** relevant to the particular virtual table being queried. 5222** 5223** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5224** ^Each term of aOrderBy records a column of the ORDER BY clause. 5225** 5226** The [xBestIndex] method must fill aConstraintUsage[] with information 5227** about what parameters to pass to xFilter. ^If argvIndex>0 then 5228** the right-hand side of the corresponding aConstraint[] is evaluated 5229** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5230** is true, then the constraint is assumed to be fully handled by the 5231** virtual table and is not checked again by SQLite.)^ 5232** 5233** ^The idxNum and idxPtr values are recorded and passed into the 5234** [xFilter] method. 5235** ^[sqlite3_free()] is used to free idxPtr if and only if 5236** needToFreeIdxPtr is true. 5237** 5238** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5239** the correct order to satisfy the ORDER BY clause so that no separate 5240** sorting step is required. 5241** 5242** ^The estimatedCost value is an estimate of the cost of doing the 5243** particular lookup. A full scan of a table with N entries should have 5244** a cost of N. A binary search of a table of N entries should have a 5245** cost of approximately log(N). 5246*/ 5247struct sqlite3_index_info { 5248 /* Inputs */ 5249 int nConstraint; /* Number of entries in aConstraint */ 5250 struct sqlite3_index_constraint { 5251 int iColumn; /* Column on left-hand side of constraint */ 5252 unsigned char op; /* Constraint operator */ 5253 unsigned char usable; /* True if this constraint is usable */ 5254 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5255 } *aConstraint; /* Table of WHERE clause constraints */ 5256 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5257 struct sqlite3_index_orderby { 5258 int iColumn; /* Column number */ 5259 unsigned char desc; /* True for DESC. False for ASC. */ 5260 } *aOrderBy; /* The ORDER BY clause */ 5261 /* Outputs */ 5262 struct sqlite3_index_constraint_usage { 5263 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5264 unsigned char omit; /* Do not code a test for this constraint */ 5265 } *aConstraintUsage; 5266 int idxNum; /* Number used to identify the index */ 5267 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5268 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5269 int orderByConsumed; /* True if output is already ordered */ 5270 double estimatedCost; /* Estimated cost of using this index */ 5271}; 5272 5273/* 5274** CAPI3REF: Virtual Table Constraint Operator Codes 5275** 5276** These macros defined the allowed values for the 5277** [sqlite3_index_info].aConstraint[].op field. Each value represents 5278** an operator that is part of a constraint term in the wHERE clause of 5279** a query that uses a [virtual table]. 5280*/ 5281#define SQLITE_INDEX_CONSTRAINT_EQ 2 5282#define SQLITE_INDEX_CONSTRAINT_GT 4 5283#define SQLITE_INDEX_CONSTRAINT_LE 8 5284#define SQLITE_INDEX_CONSTRAINT_LT 16 5285#define SQLITE_INDEX_CONSTRAINT_GE 32 5286#define SQLITE_INDEX_CONSTRAINT_MATCH 64 5287 5288/* 5289** CAPI3REF: Register A Virtual Table Implementation 5290** 5291** ^These routines are used to register a new [virtual table module] name. 5292** ^Module names must be registered before 5293** creating a new [virtual table] using the module and before using a 5294** preexisting [virtual table] for the module. 5295** 5296** ^The module name is registered on the [database connection] specified 5297** by the first parameter. ^The name of the module is given by the 5298** second parameter. ^The third parameter is a pointer to 5299** the implementation of the [virtual table module]. ^The fourth 5300** parameter is an arbitrary client data pointer that is passed through 5301** into the [xCreate] and [xConnect] methods of the virtual table module 5302** when a new virtual table is be being created or reinitialized. 5303** 5304** ^The sqlite3_create_module_v2() interface has a fifth parameter which 5305** is a pointer to a destructor for the pClientData. ^SQLite will 5306** invoke the destructor function (if it is not NULL) when SQLite 5307** no longer needs the pClientData pointer. ^The destructor will also 5308** be invoked if the call to sqlite3_create_module_v2() fails. 5309** ^The sqlite3_create_module() 5310** interface is equivalent to sqlite3_create_module_v2() with a NULL 5311** destructor. 5312*/ 5313int sqlite3_create_module( 5314 sqlite3 *db, /* SQLite connection to register module with */ 5315 const char *zName, /* Name of the module */ 5316 const sqlite3_module *p, /* Methods for the module */ 5317 void *pClientData /* Client data for xCreate/xConnect */ 5318); 5319int sqlite3_create_module_v2( 5320 sqlite3 *db, /* SQLite connection to register module with */ 5321 const char *zName, /* Name of the module */ 5322 const sqlite3_module *p, /* Methods for the module */ 5323 void *pClientData, /* Client data for xCreate/xConnect */ 5324 void(*xDestroy)(void*) /* Module destructor function */ 5325); 5326 5327/* 5328** CAPI3REF: Virtual Table Instance Object 5329** KEYWORDS: sqlite3_vtab 5330** 5331** Every [virtual table module] implementation uses a subclass 5332** of this object to describe a particular instance 5333** of the [virtual table]. Each subclass will 5334** be tailored to the specific needs of the module implementation. 5335** The purpose of this superclass is to define certain fields that are 5336** common to all module implementations. 5337** 5338** ^Virtual tables methods can set an error message by assigning a 5339** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 5340** take care that any prior string is freed by a call to [sqlite3_free()] 5341** prior to assigning a new string to zErrMsg. ^After the error message 5342** is delivered up to the client application, the string will be automatically 5343** freed by sqlite3_free() and the zErrMsg field will be zeroed. 5344*/ 5345struct sqlite3_vtab { 5346 const sqlite3_module *pModule; /* The module for this virtual table */ 5347 int nRef; /* NO LONGER USED */ 5348 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 5349 /* Virtual table implementations will typically add additional fields */ 5350}; 5351 5352/* 5353** CAPI3REF: Virtual Table Cursor Object 5354** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 5355** 5356** Every [virtual table module] implementation uses a subclass of the 5357** following structure to describe cursors that point into the 5358** [virtual table] and are used 5359** to loop through the virtual table. Cursors are created using the 5360** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 5361** by the [sqlite3_module.xClose | xClose] method. Cursors are used 5362** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 5363** of the module. Each module implementation will define 5364** the content of a cursor structure to suit its own needs. 5365** 5366** This superclass exists in order to define fields of the cursor that 5367** are common to all implementations. 5368*/ 5369struct sqlite3_vtab_cursor { 5370 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 5371 /* Virtual table implementations will typically add additional fields */ 5372}; 5373 5374/* 5375** CAPI3REF: Declare The Schema Of A Virtual Table 5376** 5377** ^The [xCreate] and [xConnect] methods of a 5378** [virtual table module] call this interface 5379** to declare the format (the names and datatypes of the columns) of 5380** the virtual tables they implement. 5381*/ 5382int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 5383 5384/* 5385** CAPI3REF: Overload A Function For A Virtual Table 5386** 5387** ^(Virtual tables can provide alternative implementations of functions 5388** using the [xFindFunction] method of the [virtual table module]. 5389** But global versions of those functions 5390** must exist in order to be overloaded.)^ 5391** 5392** ^(This API makes sure a global version of a function with a particular 5393** name and number of parameters exists. If no such function exists 5394** before this API is called, a new function is created.)^ ^The implementation 5395** of the new function always causes an exception to be thrown. So 5396** the new function is not good for anything by itself. Its only 5397** purpose is to be a placeholder function that can be overloaded 5398** by a [virtual table]. 5399*/ 5400int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5401 5402/* 5403** The interface to the virtual-table mechanism defined above (back up 5404** to a comment remarkably similar to this one) is currently considered 5405** to be experimental. The interface might change in incompatible ways. 5406** If this is a problem for you, do not use the interface at this time. 5407** 5408** When the virtual-table mechanism stabilizes, we will declare the 5409** interface fixed, support it indefinitely, and remove this comment. 5410*/ 5411 5412/* 5413** CAPI3REF: A Handle To An Open BLOB 5414** KEYWORDS: {BLOB handle} {BLOB handles} 5415** 5416** An instance of this object represents an open BLOB on which 5417** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5418** ^Objects of this type are created by [sqlite3_blob_open()] 5419** and destroyed by [sqlite3_blob_close()]. 5420** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5421** can be used to read or write small subsections of the BLOB. 5422** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5423*/ 5424typedef struct sqlite3_blob sqlite3_blob; 5425 5426/* 5427** CAPI3REF: Open A BLOB For Incremental I/O 5428** 5429** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5430** in row iRow, column zColumn, table zTable in database zDb; 5431** in other words, the same BLOB that would be selected by: 5432** 5433** <pre> 5434** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5435** </pre>)^ 5436** 5437** ^If the flags parameter is non-zero, then the BLOB is opened for read 5438** and write access. ^If it is zero, the BLOB is opened for read access. 5439** ^It is not possible to open a column that is part of an index or primary 5440** key for writing. ^If [foreign key constraints] are enabled, it is 5441** not possible to open a column that is part of a [child key] for writing. 5442** 5443** ^Note that the database name is not the filename that contains 5444** the database but rather the symbolic name of the database that 5445** appears after the AS keyword when the database is connected using [ATTACH]. 5446** ^For the main database file, the database name is "main". 5447** ^For TEMP tables, the database name is "temp". 5448** 5449** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 5450** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 5451** to be a null pointer.)^ 5452** ^This function sets the [database connection] error code and message 5453** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 5454** functions. ^Note that the *ppBlob variable is always initialized in a 5455** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 5456** regardless of the success or failure of this routine. 5457** 5458** ^(If the row that a BLOB handle points to is modified by an 5459** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5460** then the BLOB handle is marked as "expired". 5461** This is true if any column of the row is changed, even a column 5462** other than the one the BLOB handle is open on.)^ 5463** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5464** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5465** ^(Changes written into a BLOB prior to the BLOB expiring are not 5466** rolled back by the expiration of the BLOB. Such changes will eventually 5467** commit if the transaction continues to completion.)^ 5468** 5469** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5470** the opened blob. ^The size of a blob may not be changed by this 5471** interface. Use the [UPDATE] SQL command to change the size of a 5472** blob. 5473** 5474** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5475** and the built-in [zeroblob] SQL function can be used, if desired, 5476** to create an empty, zero-filled blob in which to read or write using 5477** this interface. 5478** 5479** To avoid a resource leak, every open [BLOB handle] should eventually 5480** be released by a call to [sqlite3_blob_close()]. 5481*/ 5482int sqlite3_blob_open( 5483 sqlite3*, 5484 const char *zDb, 5485 const char *zTable, 5486 const char *zColumn, 5487 sqlite3_int64 iRow, 5488 int flags, 5489 sqlite3_blob **ppBlob 5490); 5491 5492/* 5493** CAPI3REF: Move a BLOB Handle to a New Row 5494** 5495** ^This function is used to move an existing blob handle so that it points 5496** to a different row of the same database table. ^The new row is identified 5497** by the rowid value passed as the second argument. Only the row can be 5498** changed. ^The database, table and column on which the blob handle is open 5499** remain the same. Moving an existing blob handle to a new row can be 5500** faster than closing the existing handle and opening a new one. 5501** 5502** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5503** it must exist and there must be either a blob or text value stored in 5504** the nominated column.)^ ^If the new row is not present in the table, or if 5505** it does not contain a blob or text value, or if another error occurs, an 5506** SQLite error code is returned and the blob handle is considered aborted. 5507** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5508** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5509** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5510** always returns zero. 5511** 5512** ^This function sets the database handle error code and message. 5513*/ 5514SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5515 5516/* 5517** CAPI3REF: Close A BLOB Handle 5518** 5519** ^Closes an open [BLOB handle]. 5520** 5521** ^Closing a BLOB shall cause the current transaction to commit 5522** if there are no other BLOBs, no pending prepared statements, and the 5523** database connection is in [autocommit mode]. 5524** ^If any writes were made to the BLOB, they might be held in cache 5525** until the close operation if they will fit. 5526** 5527** ^(Closing the BLOB often forces the changes 5528** out to disk and so if any I/O errors occur, they will likely occur 5529** at the time when the BLOB is closed. Any errors that occur during 5530** closing are reported as a non-zero return value.)^ 5531** 5532** ^(The BLOB is closed unconditionally. Even if this routine returns 5533** an error code, the BLOB is still closed.)^ 5534** 5535** ^Calling this routine with a null pointer (such as would be returned 5536** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 5537*/ 5538int sqlite3_blob_close(sqlite3_blob *); 5539 5540/* 5541** CAPI3REF: Return The Size Of An Open BLOB 5542** 5543** ^Returns the size in bytes of the BLOB accessible via the 5544** successfully opened [BLOB handle] in its only argument. ^The 5545** incremental blob I/O routines can only read or overwriting existing 5546** blob content; they cannot change the size of a blob. 5547** 5548** This routine only works on a [BLOB handle] which has been created 5549** by a prior successful call to [sqlite3_blob_open()] and which has not 5550** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5551** to this routine results in undefined and probably undesirable behavior. 5552*/ 5553int sqlite3_blob_bytes(sqlite3_blob *); 5554 5555/* 5556** CAPI3REF: Read Data From A BLOB Incrementally 5557** 5558** ^(This function is used to read data from an open [BLOB handle] into a 5559** caller-supplied buffer. N bytes of data are copied into buffer Z 5560** from the open BLOB, starting at offset iOffset.)^ 5561** 5562** ^If offset iOffset is less than N bytes from the end of the BLOB, 5563** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 5564** less than zero, [SQLITE_ERROR] is returned and no data is read. 5565** ^The size of the blob (and hence the maximum value of N+iOffset) 5566** can be determined using the [sqlite3_blob_bytes()] interface. 5567** 5568** ^An attempt to read from an expired [BLOB handle] fails with an 5569** error code of [SQLITE_ABORT]. 5570** 5571** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 5572** Otherwise, an [error code] or an [extended error code] is returned.)^ 5573** 5574** This routine only works on a [BLOB handle] which has been created 5575** by a prior successful call to [sqlite3_blob_open()] and which has not 5576** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5577** to this routine results in undefined and probably undesirable behavior. 5578** 5579** See also: [sqlite3_blob_write()]. 5580*/ 5581int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 5582 5583/* 5584** CAPI3REF: Write Data Into A BLOB Incrementally 5585** 5586** ^This function is used to write data into an open [BLOB handle] from a 5587** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 5588** into the open BLOB, starting at offset iOffset. 5589** 5590** ^If the [BLOB handle] passed as the first argument was not opened for 5591** writing (the flags parameter to [sqlite3_blob_open()] was zero), 5592** this function returns [SQLITE_READONLY]. 5593** 5594** ^This function may only modify the contents of the BLOB; it is 5595** not possible to increase the size of a BLOB using this API. 5596** ^If offset iOffset is less than N bytes from the end of the BLOB, 5597** [SQLITE_ERROR] is returned and no data is written. ^If N is 5598** less than zero [SQLITE_ERROR] is returned and no data is written. 5599** The size of the BLOB (and hence the maximum value of N+iOffset) 5600** can be determined using the [sqlite3_blob_bytes()] interface. 5601** 5602** ^An attempt to write to an expired [BLOB handle] fails with an 5603** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 5604** before the [BLOB handle] expired are not rolled back by the 5605** expiration of the handle, though of course those changes might 5606** have been overwritten by the statement that expired the BLOB handle 5607** or by other independent statements. 5608** 5609** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 5610** Otherwise, an [error code] or an [extended error code] is returned.)^ 5611** 5612** This routine only works on a [BLOB handle] which has been created 5613** by a prior successful call to [sqlite3_blob_open()] and which has not 5614** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5615** to this routine results in undefined and probably undesirable behavior. 5616** 5617** See also: [sqlite3_blob_read()]. 5618*/ 5619int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 5620 5621/* 5622** CAPI3REF: Virtual File System Objects 5623** 5624** A virtual filesystem (VFS) is an [sqlite3_vfs] object 5625** that SQLite uses to interact 5626** with the underlying operating system. Most SQLite builds come with a 5627** single default VFS that is appropriate for the host computer. 5628** New VFSes can be registered and existing VFSes can be unregistered. 5629** The following interfaces are provided. 5630** 5631** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 5632** ^Names are case sensitive. 5633** ^Names are zero-terminated UTF-8 strings. 5634** ^If there is no match, a NULL pointer is returned. 5635** ^If zVfsName is NULL then the default VFS is returned. 5636** 5637** ^New VFSes are registered with sqlite3_vfs_register(). 5638** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 5639** ^The same VFS can be registered multiple times without injury. 5640** ^To make an existing VFS into the default VFS, register it again 5641** with the makeDflt flag set. If two different VFSes with the 5642** same name are registered, the behavior is undefined. If a 5643** VFS is registered with a name that is NULL or an empty string, 5644** then the behavior is undefined. 5645** 5646** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 5647** ^(If the default VFS is unregistered, another VFS is chosen as 5648** the default. The choice for the new VFS is arbitrary.)^ 5649*/ 5650sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 5651int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 5652int sqlite3_vfs_unregister(sqlite3_vfs*); 5653 5654/* 5655** CAPI3REF: Mutexes 5656** 5657** The SQLite core uses these routines for thread 5658** synchronization. Though they are intended for internal 5659** use by SQLite, code that links against SQLite is 5660** permitted to use any of these routines. 5661** 5662** The SQLite source code contains multiple implementations 5663** of these mutex routines. An appropriate implementation 5664** is selected automatically at compile-time. ^(The following 5665** implementations are available in the SQLite core: 5666** 5667** <ul> 5668** <li> SQLITE_MUTEX_PTHREADS 5669** <li> SQLITE_MUTEX_W32 5670** <li> SQLITE_MUTEX_NOOP 5671** </ul>)^ 5672** 5673** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 5674** that does no real locking and is appropriate for use in 5675** a single-threaded application. ^The SQLITE_MUTEX_PTHREADS and 5676** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 5677** and Windows. 5678** 5679** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 5680** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 5681** implementation is included with the library. In this case the 5682** application must supply a custom mutex implementation using the 5683** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 5684** before calling sqlite3_initialize() or any other public sqlite3_ 5685** function that calls sqlite3_initialize().)^ 5686** 5687** ^The sqlite3_mutex_alloc() routine allocates a new 5688** mutex and returns a pointer to it. ^If it returns NULL 5689** that means that a mutex could not be allocated. ^SQLite 5690** will unwind its stack and return an error. ^(The argument 5691** to sqlite3_mutex_alloc() is one of these integer constants: 5692** 5693** <ul> 5694** <li> SQLITE_MUTEX_FAST 5695** <li> SQLITE_MUTEX_RECURSIVE 5696** <li> SQLITE_MUTEX_STATIC_MASTER 5697** <li> SQLITE_MUTEX_STATIC_MEM 5698** <li> SQLITE_MUTEX_STATIC_MEM2 5699** <li> SQLITE_MUTEX_STATIC_PRNG 5700** <li> SQLITE_MUTEX_STATIC_LRU 5701** <li> SQLITE_MUTEX_STATIC_LRU2 5702** </ul>)^ 5703** 5704** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 5705** cause sqlite3_mutex_alloc() to create 5706** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 5707** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 5708** The mutex implementation does not need to make a distinction 5709** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 5710** not want to. ^SQLite will only request a recursive mutex in 5711** cases where it really needs one. ^If a faster non-recursive mutex 5712** implementation is available on the host platform, the mutex subsystem 5713** might return such a mutex in response to SQLITE_MUTEX_FAST. 5714** 5715** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 5716** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 5717** a pointer to a static preexisting mutex. ^Six static mutexes are 5718** used by the current version of SQLite. Future versions of SQLite 5719** may add additional static mutexes. Static mutexes are for internal 5720** use by SQLite only. Applications that use SQLite mutexes should 5721** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 5722** SQLITE_MUTEX_RECURSIVE. 5723** 5724** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 5725** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 5726** returns a different mutex on every call. ^But for the static 5727** mutex types, the same mutex is returned on every call that has 5728** the same type number. 5729** 5730** ^The sqlite3_mutex_free() routine deallocates a previously 5731** allocated dynamic mutex. ^SQLite is careful to deallocate every 5732** dynamic mutex that it allocates. The dynamic mutexes must not be in 5733** use when they are deallocated. Attempting to deallocate a static 5734** mutex results in undefined behavior. ^SQLite never deallocates 5735** a static mutex. 5736** 5737** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 5738** to enter a mutex. ^If another thread is already within the mutex, 5739** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 5740** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 5741** upon successful entry. ^(Mutexes created using 5742** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 5743** In such cases the, 5744** mutex must be exited an equal number of times before another thread 5745** can enter.)^ ^(If the same thread tries to enter any other 5746** kind of mutex more than once, the behavior is undefined. 5747** SQLite will never exhibit 5748** such behavior in its own use of mutexes.)^ 5749** 5750** ^(Some systems (for example, Windows 95) do not support the operation 5751** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 5752** will always return SQLITE_BUSY. The SQLite core only ever uses 5753** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 5754** 5755** ^The sqlite3_mutex_leave() routine exits a mutex that was 5756** previously entered by the same thread. ^(The behavior 5757** is undefined if the mutex is not currently entered by the 5758** calling thread or is not currently allocated. SQLite will 5759** never do either.)^ 5760** 5761** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 5762** sqlite3_mutex_leave() is a NULL pointer, then all three routines 5763** behave as no-ops. 5764** 5765** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 5766*/ 5767sqlite3_mutex *sqlite3_mutex_alloc(int); 5768void sqlite3_mutex_free(sqlite3_mutex*); 5769void sqlite3_mutex_enter(sqlite3_mutex*); 5770int sqlite3_mutex_try(sqlite3_mutex*); 5771void sqlite3_mutex_leave(sqlite3_mutex*); 5772 5773/* 5774** CAPI3REF: Mutex Methods Object 5775** 5776** An instance of this structure defines the low-level routines 5777** used to allocate and use mutexes. 5778** 5779** Usually, the default mutex implementations provided by SQLite are 5780** sufficient, however the user has the option of substituting a custom 5781** implementation for specialized deployments or systems for which SQLite 5782** does not provide a suitable implementation. In this case, the user 5783** creates and populates an instance of this structure to pass 5784** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 5785** Additionally, an instance of this structure can be used as an 5786** output variable when querying the system for the current mutex 5787** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 5788** 5789** ^The xMutexInit method defined by this structure is invoked as 5790** part of system initialization by the sqlite3_initialize() function. 5791** ^The xMutexInit routine is called by SQLite exactly once for each 5792** effective call to [sqlite3_initialize()]. 5793** 5794** ^The xMutexEnd method defined by this structure is invoked as 5795** part of system shutdown by the sqlite3_shutdown() function. The 5796** implementation of this method is expected to release all outstanding 5797** resources obtained by the mutex methods implementation, especially 5798** those obtained by the xMutexInit method. ^The xMutexEnd() 5799** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 5800** 5801** ^(The remaining seven methods defined by this structure (xMutexAlloc, 5802** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 5803** xMutexNotheld) implement the following interfaces (respectively): 5804** 5805** <ul> 5806** <li> [sqlite3_mutex_alloc()] </li> 5807** <li> [sqlite3_mutex_free()] </li> 5808** <li> [sqlite3_mutex_enter()] </li> 5809** <li> [sqlite3_mutex_try()] </li> 5810** <li> [sqlite3_mutex_leave()] </li> 5811** <li> [sqlite3_mutex_held()] </li> 5812** <li> [sqlite3_mutex_notheld()] </li> 5813** </ul>)^ 5814** 5815** The only difference is that the public sqlite3_XXX functions enumerated 5816** above silently ignore any invocations that pass a NULL pointer instead 5817** of a valid mutex handle. The implementations of the methods defined 5818** by this structure are not required to handle this case, the results 5819** of passing a NULL pointer instead of a valid mutex handle are undefined 5820** (i.e. it is acceptable to provide an implementation that segfaults if 5821** it is passed a NULL pointer). 5822** 5823** The xMutexInit() method must be threadsafe. ^It must be harmless to 5824** invoke xMutexInit() multiple times within the same process and without 5825** intervening calls to xMutexEnd(). Second and subsequent calls to 5826** xMutexInit() must be no-ops. 5827** 5828** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 5829** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 5830** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 5831** memory allocation for a fast or recursive mutex. 5832** 5833** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 5834** called, but only if the prior call to xMutexInit returned SQLITE_OK. 5835** If xMutexInit fails in any way, it is expected to clean up after itself 5836** prior to returning. 5837*/ 5838typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 5839struct sqlite3_mutex_methods { 5840 int (*xMutexInit)(void); 5841 int (*xMutexEnd)(void); 5842 sqlite3_mutex *(*xMutexAlloc)(int); 5843 void (*xMutexFree)(sqlite3_mutex *); 5844 void (*xMutexEnter)(sqlite3_mutex *); 5845 int (*xMutexTry)(sqlite3_mutex *); 5846 void (*xMutexLeave)(sqlite3_mutex *); 5847 int (*xMutexHeld)(sqlite3_mutex *); 5848 int (*xMutexNotheld)(sqlite3_mutex *); 5849}; 5850 5851/* 5852** CAPI3REF: Mutex Verification Routines 5853** 5854** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 5855** are intended for use inside assert() statements. ^The SQLite core 5856** never uses these routines except inside an assert() and applications 5857** are advised to follow the lead of the core. ^The SQLite core only 5858** provides implementations for these routines when it is compiled 5859** with the SQLITE_DEBUG flag. ^External mutex implementations 5860** are only required to provide these routines if SQLITE_DEBUG is 5861** defined and if NDEBUG is not defined. 5862** 5863** ^These routines should return true if the mutex in their argument 5864** is held or not held, respectively, by the calling thread. 5865** 5866** ^The implementation is not required to provide versions of these 5867** routines that actually work. If the implementation does not provide working 5868** versions of these routines, it should at least provide stubs that always 5869** return true so that one does not get spurious assertion failures. 5870** 5871** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 5872** the routine should return 1. This seems counter-intuitive since 5873** clearly the mutex cannot be held if it does not exist. But 5874** the reason the mutex does not exist is because the build is not 5875** using mutexes. And we do not want the assert() containing the 5876** call to sqlite3_mutex_held() to fail, so a non-zero return is 5877** the appropriate thing to do. ^The sqlite3_mutex_notheld() 5878** interface should also return 1 when given a NULL pointer. 5879*/ 5880#ifndef NDEBUG 5881int sqlite3_mutex_held(sqlite3_mutex*); 5882int sqlite3_mutex_notheld(sqlite3_mutex*); 5883#endif 5884 5885/* 5886** CAPI3REF: Mutex Types 5887** 5888** The [sqlite3_mutex_alloc()] interface takes a single argument 5889** which is one of these integer constants. 5890** 5891** The set of static mutexes may change from one SQLite release to the 5892** next. Applications that override the built-in mutex logic must be 5893** prepared to accommodate additional static mutexes. 5894*/ 5895#define SQLITE_MUTEX_FAST 0 5896#define SQLITE_MUTEX_RECURSIVE 1 5897#define SQLITE_MUTEX_STATIC_MASTER 2 5898#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 5899#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 5900#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 5901#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 5902#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 5903#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 5904#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 5905 5906/* 5907** CAPI3REF: Retrieve the mutex for a database connection 5908** 5909** ^This interface returns a pointer the [sqlite3_mutex] object that 5910** serializes access to the [database connection] given in the argument 5911** when the [threading mode] is Serialized. 5912** ^If the [threading mode] is Single-thread or Multi-thread then this 5913** routine returns a NULL pointer. 5914*/ 5915sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 5916 5917/* 5918** CAPI3REF: Low-Level Control Of Database Files 5919** 5920** ^The [sqlite3_file_control()] interface makes a direct call to the 5921** xFileControl method for the [sqlite3_io_methods] object associated 5922** with a particular database identified by the second argument. ^The 5923** name of the database is "main" for the main database or "temp" for the 5924** TEMP database, or the name that appears after the AS keyword for 5925** databases that are added using the [ATTACH] SQL command. 5926** ^A NULL pointer can be used in place of "main" to refer to the 5927** main database file. 5928** ^The third and fourth parameters to this routine 5929** are passed directly through to the second and third parameters of 5930** the xFileControl method. ^The return value of the xFileControl 5931** method becomes the return value of this routine. 5932** 5933** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 5934** a pointer to the underlying [sqlite3_file] object to be written into 5935** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 5936** case is a short-circuit path which does not actually invoke the 5937** underlying sqlite3_io_methods.xFileControl method. 5938** 5939** ^If the second parameter (zDbName) does not match the name of any 5940** open database file, then SQLITE_ERROR is returned. ^This error 5941** code is not remembered and will not be recalled by [sqlite3_errcode()] 5942** or [sqlite3_errmsg()]. The underlying xFileControl method might 5943** also return SQLITE_ERROR. There is no way to distinguish between 5944** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5945** xFileControl method. 5946** 5947** See also: [SQLITE_FCNTL_LOCKSTATE] 5948*/ 5949int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5950 5951/* 5952** CAPI3REF: Testing Interface 5953** 5954** ^The sqlite3_test_control() interface is used to read out internal 5955** state of SQLite and to inject faults into SQLite for testing 5956** purposes. ^The first parameter is an operation code that determines 5957** the number, meaning, and operation of all subsequent parameters. 5958** 5959** This interface is not for use by applications. It exists solely 5960** for verifying the correct operation of the SQLite library. Depending 5961** on how the SQLite library is compiled, this interface might not exist. 5962** 5963** The details of the operation codes, their meanings, the parameters 5964** they take, and what they do are all subject to change without notice. 5965** Unlike most of the SQLite API, this function is not guaranteed to 5966** operate consistently from one release to the next. 5967*/ 5968int sqlite3_test_control(int op, ...); 5969 5970/* 5971** CAPI3REF: Testing Interface Operation Codes 5972** 5973** These constants are the valid operation code parameters used 5974** as the first argument to [sqlite3_test_control()]. 5975** 5976** These parameters and their meanings are subject to change 5977** without notice. These values are for testing purposes only. 5978** Applications should not use any of these parameters or the 5979** [sqlite3_test_control()] interface. 5980*/ 5981#define SQLITE_TESTCTRL_FIRST 5 5982#define SQLITE_TESTCTRL_PRNG_SAVE 5 5983#define SQLITE_TESTCTRL_PRNG_RESTORE 6 5984#define SQLITE_TESTCTRL_PRNG_RESET 7 5985#define SQLITE_TESTCTRL_BITVEC_TEST 8 5986#define SQLITE_TESTCTRL_FAULT_INSTALL 9 5987#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5988#define SQLITE_TESTCTRL_PENDING_BYTE 11 5989#define SQLITE_TESTCTRL_ASSERT 12 5990#define SQLITE_TESTCTRL_ALWAYS 13 5991#define SQLITE_TESTCTRL_RESERVE 14 5992#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 5993#define SQLITE_TESTCTRL_ISKEYWORD 16 5994#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 5995#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 5996#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 5997#define SQLITE_TESTCTRL_LAST 19 5998 5999/* 6000** CAPI3REF: SQLite Runtime Status 6001** 6002** ^This interface is used to retrieve runtime status information 6003** about the performance of SQLite, and optionally to reset various 6004** highwater marks. ^The first argument is an integer code for 6005** the specific parameter to measure. ^(Recognized integer codes 6006** are of the form [status parameters | SQLITE_STATUS_...].)^ 6007** ^The current value of the parameter is returned into *pCurrent. 6008** ^The highest recorded value is returned in *pHighwater. ^If the 6009** resetFlag is true, then the highest record value is reset after 6010** *pHighwater is written. ^(Some parameters do not record the highest 6011** value. For those parameters 6012** nothing is written into *pHighwater and the resetFlag is ignored.)^ 6013** ^(Other parameters record only the highwater mark and not the current 6014** value. For these latter parameters nothing is written into *pCurrent.)^ 6015** 6016** ^The sqlite3_status() routine returns SQLITE_OK on success and a 6017** non-zero [error code] on failure. 6018** 6019** This routine is threadsafe but is not atomic. This routine can be 6020** called while other threads are running the same or different SQLite 6021** interfaces. However the values returned in *pCurrent and 6022** *pHighwater reflect the status of SQLite at different points in time 6023** and it is possible that another thread might change the parameter 6024** in between the times when *pCurrent and *pHighwater are written. 6025** 6026** See also: [sqlite3_db_status()] 6027*/ 6028int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 6029 6030 6031/* 6032** CAPI3REF: Status Parameters 6033** KEYWORDS: {status parameters} 6034** 6035** These integer constants designate various run-time status parameters 6036** that can be returned by [sqlite3_status()]. 6037** 6038** <dl> 6039** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 6040** <dd>This parameter is the current amount of memory checked out 6041** using [sqlite3_malloc()], either directly or indirectly. The 6042** figure includes calls made to [sqlite3_malloc()] by the application 6043** and internal memory usage by the SQLite library. Scratch memory 6044** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 6045** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 6046** this parameter. The amount returned is the sum of the allocation 6047** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 6048** 6049** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 6050** <dd>This parameter records the largest memory allocation request 6051** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 6052** internal equivalents). Only the value returned in the 6053** *pHighwater parameter to [sqlite3_status()] is of interest. 6054** The value written into the *pCurrent parameter is undefined.</dd>)^ 6055** 6056** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 6057** <dd>This parameter records the number of separate memory allocations 6058** currently checked out.</dd>)^ 6059** 6060** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 6061** <dd>This parameter returns the number of pages used out of the 6062** [pagecache memory allocator] that was configured using 6063** [SQLITE_CONFIG_PAGECACHE]. The 6064** value returned is in pages, not in bytes.</dd>)^ 6065** 6066** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 6067** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 6068** <dd>This parameter returns the number of bytes of page cache 6069** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 6070** buffer and where forced to overflow to [sqlite3_malloc()]. The 6071** returned value includes allocations that overflowed because they 6072** where too large (they were larger than the "sz" parameter to 6073** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 6074** no space was left in the page cache.</dd>)^ 6075** 6076** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 6077** <dd>This parameter records the largest memory allocation request 6078** handed to [pagecache memory allocator]. Only the value returned in the 6079** *pHighwater parameter to [sqlite3_status()] is of interest. 6080** The value written into the *pCurrent parameter is undefined.</dd>)^ 6081** 6082** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 6083** <dd>This parameter returns the number of allocations used out of the 6084** [scratch memory allocator] configured using 6085** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 6086** in bytes. Since a single thread may only have one scratch allocation 6087** outstanding at time, this parameter also reports the number of threads 6088** using scratch memory at the same time.</dd>)^ 6089** 6090** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 6091** <dd>This parameter returns the number of bytes of scratch memory 6092** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 6093** buffer and where forced to overflow to [sqlite3_malloc()]. The values 6094** returned include overflows because the requested allocation was too 6095** larger (that is, because the requested allocation was larger than the 6096** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 6097** slots were available. 6098** </dd>)^ 6099** 6100** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 6101** <dd>This parameter records the largest memory allocation request 6102** handed to [scratch memory allocator]. Only the value returned in the 6103** *pHighwater parameter to [sqlite3_status()] is of interest. 6104** The value written into the *pCurrent parameter is undefined.</dd>)^ 6105** 6106** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 6107** <dd>This parameter records the deepest parser stack. It is only 6108** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 6109** </dl> 6110** 6111** New status parameters may be added from time to time. 6112*/ 6113#define SQLITE_STATUS_MEMORY_USED 0 6114#define SQLITE_STATUS_PAGECACHE_USED 1 6115#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 6116#define SQLITE_STATUS_SCRATCH_USED 3 6117#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 6118#define SQLITE_STATUS_MALLOC_SIZE 5 6119#define SQLITE_STATUS_PARSER_STACK 6 6120#define SQLITE_STATUS_PAGECACHE_SIZE 7 6121#define SQLITE_STATUS_SCRATCH_SIZE 8 6122#define SQLITE_STATUS_MALLOC_COUNT 9 6123 6124/* 6125** CAPI3REF: Database Connection Status 6126** 6127** ^This interface is used to retrieve runtime status information 6128** about a single [database connection]. ^The first argument is the 6129** database connection object to be interrogated. ^The second argument 6130** is an integer constant, taken from the set of 6131** [SQLITE_DBSTATUS options], that 6132** determines the parameter to interrogate. The set of 6133** [SQLITE_DBSTATUS options] is likely 6134** to grow in future releases of SQLite. 6135** 6136** ^The current value of the requested parameter is written into *pCur 6137** and the highest instantaneous value is written into *pHiwtr. ^If 6138** the resetFlg is true, then the highest instantaneous value is 6139** reset back down to the current value. 6140** 6141** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 6142** non-zero [error code] on failure. 6143** 6144** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 6145*/ 6146int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 6147 6148/* 6149** CAPI3REF: Status Parameters for database connections 6150** KEYWORDS: {SQLITE_DBSTATUS options} 6151** 6152** These constants are the available integer "verbs" that can be passed as 6153** the second argument to the [sqlite3_db_status()] interface. 6154** 6155** New verbs may be added in future releases of SQLite. Existing verbs 6156** might be discontinued. Applications should check the return code from 6157** [sqlite3_db_status()] to make sure that the call worked. 6158** The [sqlite3_db_status()] interface will return a non-zero error code 6159** if a discontinued or unsupported verb is invoked. 6160** 6161** <dl> 6162** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 6163** <dd>This parameter returns the number of lookaside memory slots currently 6164** checked out.</dd>)^ 6165** 6166** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 6167** <dd>This parameter returns the number malloc attempts that were 6168** satisfied using lookaside memory. Only the high-water value is meaningful; 6169** the current value is always zero.)^ 6170** 6171** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 6172** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 6173** <dd>This parameter returns the number malloc attempts that might have 6174** been satisfied using lookaside memory but failed due to the amount of 6175** memory requested being larger than the lookaside slot size. 6176** Only the high-water value is meaningful; 6177** the current value is always zero.)^ 6178** 6179** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 6180** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 6181** <dd>This parameter returns the number malloc attempts that might have 6182** been satisfied using lookaside memory but failed due to all lookaside 6183** memory already being in use. 6184** Only the high-water value is meaningful; 6185** the current value is always zero.)^ 6186** 6187** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 6188** <dd>This parameter returns the approximate number of of bytes of heap 6189** memory used by all pager caches associated with the database connection.)^ 6190** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 6191** 6192** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 6193** <dd>This parameter returns the approximate number of of bytes of heap 6194** memory used to store the schema for all databases associated 6195** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 6196** ^The full amount of memory used by the schemas is reported, even if the 6197** schema memory is shared with other database connections due to 6198** [shared cache mode] being enabled. 6199** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 6200** 6201** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 6202** <dd>This parameter returns the approximate number of of bytes of heap 6203** and lookaside memory used by all prepared statements associated with 6204** the database connection.)^ 6205** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 6206** </dd> 6207** 6208** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 6209** <dd>This parameter returns the number of pager cache hits that have 6210** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 6211** is always 0. 6212** </dd> 6213** 6214** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6215** <dd>This parameter returns the number of pager cache misses that have 6216** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6217** is always 0. 6218** </dd> 6219** 6220** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 6221** <dd>This parameter returns the number of dirty cache entries that have 6222** been written to disk. Specifically, the number of pages written to the 6223** wal file in wal mode databases, or the number of pages written to the 6224** database file in rollback mode databases. Any pages written as part of 6225** transaction rollback or database recovery operations are not included. 6226** If an IO or other error occurs while writing a page to disk, the effect 6227** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 6228** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 6229** </dd> 6230** </dl> 6231*/ 6232#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6233#define SQLITE_DBSTATUS_CACHE_USED 1 6234#define SQLITE_DBSTATUS_SCHEMA_USED 2 6235#define SQLITE_DBSTATUS_STMT_USED 3 6236#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6237#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6238#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 6239#define SQLITE_DBSTATUS_CACHE_HIT 7 6240#define SQLITE_DBSTATUS_CACHE_MISS 8 6241#define SQLITE_DBSTATUS_CACHE_WRITE 9 6242#define SQLITE_DBSTATUS_MAX 9 /* Largest defined DBSTATUS */ 6243 6244 6245/* 6246** CAPI3REF: Prepared Statement Status 6247** 6248** ^(Each prepared statement maintains various 6249** [SQLITE_STMTSTATUS counters] that measure the number 6250** of times it has performed specific operations.)^ These counters can 6251** be used to monitor the performance characteristics of the prepared 6252** statements. For example, if the number of table steps greatly exceeds 6253** the number of table searches or result rows, that would tend to indicate 6254** that the prepared statement is using a full table scan rather than 6255** an index. 6256** 6257** ^(This interface is used to retrieve and reset counter values from 6258** a [prepared statement]. The first argument is the prepared statement 6259** object to be interrogated. The second argument 6260** is an integer code for a specific [SQLITE_STMTSTATUS counter] 6261** to be interrogated.)^ 6262** ^The current value of the requested counter is returned. 6263** ^If the resetFlg is true, then the counter is reset to zero after this 6264** interface call returns. 6265** 6266** See also: [sqlite3_status()] and [sqlite3_db_status()]. 6267*/ 6268int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 6269 6270/* 6271** CAPI3REF: Status Parameters for prepared statements 6272** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 6273** 6274** These preprocessor macros define integer codes that name counter 6275** values associated with the [sqlite3_stmt_status()] interface. 6276** The meanings of the various counters are as follows: 6277** 6278** <dl> 6279** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 6280** <dd>^This is the number of times that SQLite has stepped forward in 6281** a table as part of a full table scan. Large numbers for this counter 6282** may indicate opportunities for performance improvement through 6283** careful use of indices.</dd> 6284** 6285** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 6286** <dd>^This is the number of sort operations that have occurred. 6287** A non-zero value in this counter may indicate an opportunity to 6288** improvement performance through careful use of indices.</dd> 6289** 6290** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 6291** <dd>^This is the number of rows inserted into transient indices that 6292** were created automatically in order to help joins run faster. 6293** A non-zero value in this counter may indicate an opportunity to 6294** improvement performance by adding permanent indices that do not 6295** need to be reinitialized each time the statement is run.</dd> 6296** </dl> 6297*/ 6298#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 6299#define SQLITE_STMTSTATUS_SORT 2 6300#define SQLITE_STMTSTATUS_AUTOINDEX 3 6301 6302/* 6303** CAPI3REF: Custom Page Cache Object 6304** 6305** The sqlite3_pcache type is opaque. It is implemented by 6306** the pluggable module. The SQLite core has no knowledge of 6307** its size or internal structure and never deals with the 6308** sqlite3_pcache object except by holding and passing pointers 6309** to the object. 6310** 6311** See [sqlite3_pcache_methods2] for additional information. 6312*/ 6313typedef struct sqlite3_pcache sqlite3_pcache; 6314 6315/* 6316** CAPI3REF: Custom Page Cache Object 6317** 6318** The sqlite3_pcache_page object represents a single page in the 6319** page cache. The page cache will allocate instances of this 6320** object. Various methods of the page cache use pointers to instances 6321** of this object as parameters or as their return value. 6322** 6323** See [sqlite3_pcache_methods2] for additional information. 6324*/ 6325typedef struct sqlite3_pcache_page sqlite3_pcache_page; 6326struct sqlite3_pcache_page { 6327 void *pBuf; /* The content of the page */ 6328 void *pExtra; /* Extra information associated with the page */ 6329}; 6330 6331/* 6332** CAPI3REF: Application Defined Page Cache. 6333** KEYWORDS: {page cache} 6334** 6335** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 6336** register an alternative page cache implementation by passing in an 6337** instance of the sqlite3_pcache_methods2 structure.)^ 6338** In many applications, most of the heap memory allocated by 6339** SQLite is used for the page cache. 6340** By implementing a 6341** custom page cache using this API, an application can better control 6342** the amount of memory consumed by SQLite, the way in which 6343** that memory is allocated and released, and the policies used to 6344** determine exactly which parts of a database file are cached and for 6345** how long. 6346** 6347** The alternative page cache mechanism is an 6348** extreme measure that is only needed by the most demanding applications. 6349** The built-in page cache is recommended for most uses. 6350** 6351** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 6352** internal buffer by SQLite within the call to [sqlite3_config]. Hence 6353** the application may discard the parameter after the call to 6354** [sqlite3_config()] returns.)^ 6355** 6356** [[the xInit() page cache method]] 6357** ^(The xInit() method is called once for each effective 6358** call to [sqlite3_initialize()])^ 6359** (usually only once during the lifetime of the process). ^(The xInit() 6360** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 6361** The intent of the xInit() method is to set up global data structures 6362** required by the custom page cache implementation. 6363** ^(If the xInit() method is NULL, then the 6364** built-in default page cache is used instead of the application defined 6365** page cache.)^ 6366** 6367** [[the xShutdown() page cache method]] 6368** ^The xShutdown() method is called by [sqlite3_shutdown()]. 6369** It can be used to clean up 6370** any outstanding resources before process shutdown, if required. 6371** ^The xShutdown() method may be NULL. 6372** 6373** ^SQLite automatically serializes calls to the xInit method, 6374** so the xInit method need not be threadsafe. ^The 6375** xShutdown method is only called from [sqlite3_shutdown()] so it does 6376** not need to be threadsafe either. All other methods must be threadsafe 6377** in multithreaded applications. 6378** 6379** ^SQLite will never invoke xInit() more than once without an intervening 6380** call to xShutdown(). 6381** 6382** [[the xCreate() page cache methods]] 6383** ^SQLite invokes the xCreate() method to construct a new cache instance. 6384** SQLite will typically create one cache instance for each open database file, 6385** though this is not guaranteed. ^The 6386** first parameter, szPage, is the size in bytes of the pages that must 6387** be allocated by the cache. ^szPage will always a power of two. ^The 6388** second parameter szExtra is a number of bytes of extra storage 6389** associated with each page cache entry. ^The szExtra parameter will 6390** a number less than 250. SQLite will use the 6391** extra szExtra bytes on each page to store metadata about the underlying 6392** database page on disk. The value passed into szExtra depends 6393** on the SQLite version, the target platform, and how SQLite was compiled. 6394** ^The third argument to xCreate(), bPurgeable, is true if the cache being 6395** created will be used to cache database pages of a file stored on disk, or 6396** false if it is used for an in-memory database. The cache implementation 6397** does not have to do anything special based with the value of bPurgeable; 6398** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 6399** never invoke xUnpin() except to deliberately delete a page. 6400** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 6401** false will always have the "discard" flag set to true. 6402** ^Hence, a cache created with bPurgeable false will 6403** never contain any unpinned pages. 6404** 6405** [[the xCachesize() page cache method]] 6406** ^(The xCachesize() method may be called at any time by SQLite to set the 6407** suggested maximum cache-size (number of pages stored by) the cache 6408** instance passed as the first argument. This is the value configured using 6409** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 6410** parameter, the implementation is not required to do anything with this 6411** value; it is advisory only. 6412** 6413** [[the xPagecount() page cache methods]] 6414** The xPagecount() method must return the number of pages currently 6415** stored in the cache, both pinned and unpinned. 6416** 6417** [[the xFetch() page cache methods]] 6418** The xFetch() method locates a page in the cache and returns a pointer to 6419** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 6420** The pBuf element of the returned sqlite3_pcache_page object will be a 6421** pointer to a buffer of szPage bytes used to store the content of a 6422** single database page. The pExtra element of sqlite3_pcache_page will be 6423** a pointer to the szExtra bytes of extra storage that SQLite has requested 6424** for each entry in the page cache. 6425** 6426** The page to be fetched is determined by the key. ^The minimum key value 6427** is 1. After it has been retrieved using xFetch, the page is considered 6428** to be "pinned". 6429** 6430** If the requested page is already in the page cache, then the page cache 6431** implementation must return a pointer to the page buffer with its content 6432** intact. If the requested page is not already in the cache, then the 6433** cache implementation should use the value of the createFlag 6434** parameter to help it determined what action to take: 6435** 6436** <table border=1 width=85% align=center> 6437** <tr><th> createFlag <th> Behavior when page is not already in cache 6438** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6439** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6440** Otherwise return NULL. 6441** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6442** NULL if allocating a new page is effectively impossible. 6443** </table> 6444** 6445** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6446** will only use a createFlag of 2 after a prior call with a createFlag of 1 6447** failed.)^ In between the to xFetch() calls, SQLite may 6448** attempt to unpin one or more cache pages by spilling the content of 6449** pinned pages to disk and synching the operating system disk cache. 6450** 6451** [[the xUnpin() page cache method]] 6452** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6453** as its second argument. If the third parameter, discard, is non-zero, 6454** then the page must be evicted from the cache. 6455** ^If the discard parameter is 6456** zero, then the page may be discarded or retained at the discretion of 6457** page cache implementation. ^The page cache implementation 6458** may choose to evict unpinned pages at any time. 6459** 6460** The cache must not perform any reference counting. A single 6461** call to xUnpin() unpins the page regardless of the number of prior calls 6462** to xFetch(). 6463** 6464** [[the xRekey() page cache methods]] 6465** The xRekey() method is used to change the key value associated with the 6466** page passed as the second argument. If the cache 6467** previously contains an entry associated with newKey, it must be 6468** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6469** to be pinned. 6470** 6471** When SQLite calls the xTruncate() method, the cache must discard all 6472** existing cache entries with page numbers (keys) greater than or equal 6473** to the value of the iLimit parameter passed to xTruncate(). If any 6474** of these pages are pinned, they are implicitly unpinned, meaning that 6475** they can be safely discarded. 6476** 6477** [[the xDestroy() page cache method]] 6478** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6479** All resources associated with the specified cache should be freed. ^After 6480** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6481** handle invalid, and will not use it with any other sqlite3_pcache_methods2 6482** functions. 6483** 6484** [[the xShrink() page cache method]] 6485** ^SQLite invokes the xShrink() method when it wants the page cache to 6486** free up as much of heap memory as possible. The page cache implementation 6487** is not obligated to free any memory, but well-behaved implementations should 6488** do their best. 6489*/ 6490typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 6491struct sqlite3_pcache_methods2 { 6492 int iVersion; 6493 void *pArg; 6494 int (*xInit)(void*); 6495 void (*xShutdown)(void*); 6496 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 6497 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6498 int (*xPagecount)(sqlite3_pcache*); 6499 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6500 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 6501 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 6502 unsigned oldKey, unsigned newKey); 6503 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6504 void (*xDestroy)(sqlite3_pcache*); 6505 void (*xShrink)(sqlite3_pcache*); 6506}; 6507 6508/* 6509** This is the obsolete pcache_methods object that has now been replaced 6510** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 6511** retained in the header file for backwards compatibility only. 6512*/ 6513typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 6514struct sqlite3_pcache_methods { 6515 void *pArg; 6516 int (*xInit)(void*); 6517 void (*xShutdown)(void*); 6518 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 6519 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6520 int (*xPagecount)(sqlite3_pcache*); 6521 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6522 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 6523 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 6524 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6525 void (*xDestroy)(sqlite3_pcache*); 6526}; 6527 6528 6529/* 6530** CAPI3REF: Online Backup Object 6531** 6532** The sqlite3_backup object records state information about an ongoing 6533** online backup operation. ^The sqlite3_backup object is created by 6534** a call to [sqlite3_backup_init()] and is destroyed by a call to 6535** [sqlite3_backup_finish()]. 6536** 6537** See Also: [Using the SQLite Online Backup API] 6538*/ 6539typedef struct sqlite3_backup sqlite3_backup; 6540 6541/* 6542** CAPI3REF: Online Backup API. 6543** 6544** The backup API copies the content of one database into another. 6545** It is useful either for creating backups of databases or 6546** for copying in-memory databases to or from persistent files. 6547** 6548** See Also: [Using the SQLite Online Backup API] 6549** 6550** ^SQLite holds a write transaction open on the destination database file 6551** for the duration of the backup operation. 6552** ^The source database is read-locked only while it is being read; 6553** it is not locked continuously for the entire backup operation. 6554** ^Thus, the backup may be performed on a live source database without 6555** preventing other database connections from 6556** reading or writing to the source database while the backup is underway. 6557** 6558** ^(To perform a backup operation: 6559** <ol> 6560** <li><b>sqlite3_backup_init()</b> is called once to initialize the 6561** backup, 6562** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 6563** the data between the two databases, and finally 6564** <li><b>sqlite3_backup_finish()</b> is called to release all resources 6565** associated with the backup operation. 6566** </ol>)^ 6567** There should be exactly one call to sqlite3_backup_finish() for each 6568** successful call to sqlite3_backup_init(). 6569** 6570** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 6571** 6572** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 6573** [database connection] associated with the destination database 6574** and the database name, respectively. 6575** ^The database name is "main" for the main database, "temp" for the 6576** temporary database, or the name specified after the AS keyword in 6577** an [ATTACH] statement for an attached database. 6578** ^The S and M arguments passed to 6579** sqlite3_backup_init(D,N,S,M) identify the [database connection] 6580** and database name of the source database, respectively. 6581** ^The source and destination [database connections] (parameters S and D) 6582** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 6583** an error. 6584** 6585** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 6586** returned and an error code and error message are stored in the 6587** destination [database connection] D. 6588** ^The error code and message for the failed call to sqlite3_backup_init() 6589** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 6590** [sqlite3_errmsg16()] functions. 6591** ^A successful call to sqlite3_backup_init() returns a pointer to an 6592** [sqlite3_backup] object. 6593** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 6594** sqlite3_backup_finish() functions to perform the specified backup 6595** operation. 6596** 6597** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 6598** 6599** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 6600** the source and destination databases specified by [sqlite3_backup] object B. 6601** ^If N is negative, all remaining source pages are copied. 6602** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 6603** are still more pages to be copied, then the function returns [SQLITE_OK]. 6604** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 6605** from source to destination, then it returns [SQLITE_DONE]. 6606** ^If an error occurs while running sqlite3_backup_step(B,N), 6607** then an [error code] is returned. ^As well as [SQLITE_OK] and 6608** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 6609** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 6610** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 6611** 6612** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 6613** <ol> 6614** <li> the destination database was opened read-only, or 6615** <li> the destination database is using write-ahead-log journaling 6616** and the destination and source page sizes differ, or 6617** <li> the destination database is an in-memory database and the 6618** destination and source page sizes differ. 6619** </ol>)^ 6620** 6621** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 6622** the [sqlite3_busy_handler | busy-handler function] 6623** is invoked (if one is specified). ^If the 6624** busy-handler returns non-zero before the lock is available, then 6625** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 6626** sqlite3_backup_step() can be retried later. ^If the source 6627** [database connection] 6628** is being used to write to the source database when sqlite3_backup_step() 6629** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 6630** case the call to sqlite3_backup_step() can be retried later on. ^(If 6631** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 6632** [SQLITE_READONLY] is returned, then 6633** there is no point in retrying the call to sqlite3_backup_step(). These 6634** errors are considered fatal.)^ The application must accept 6635** that the backup operation has failed and pass the backup operation handle 6636** to the sqlite3_backup_finish() to release associated resources. 6637** 6638** ^The first call to sqlite3_backup_step() obtains an exclusive lock 6639** on the destination file. ^The exclusive lock is not released until either 6640** sqlite3_backup_finish() is called or the backup operation is complete 6641** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 6642** sqlite3_backup_step() obtains a [shared lock] on the source database that 6643** lasts for the duration of the sqlite3_backup_step() call. 6644** ^Because the source database is not locked between calls to 6645** sqlite3_backup_step(), the source database may be modified mid-way 6646** through the backup process. ^If the source database is modified by an 6647** external process or via a database connection other than the one being 6648** used by the backup operation, then the backup will be automatically 6649** restarted by the next call to sqlite3_backup_step(). ^If the source 6650** database is modified by the using the same database connection as is used 6651** by the backup operation, then the backup database is automatically 6652** updated at the same time. 6653** 6654** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 6655** 6656** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 6657** application wishes to abandon the backup operation, the application 6658** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 6659** ^The sqlite3_backup_finish() interfaces releases all 6660** resources associated with the [sqlite3_backup] object. 6661** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 6662** active write-transaction on the destination database is rolled back. 6663** The [sqlite3_backup] object is invalid 6664** and may not be used following a call to sqlite3_backup_finish(). 6665** 6666** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 6667** sqlite3_backup_step() errors occurred, regardless or whether or not 6668** sqlite3_backup_step() completed. 6669** ^If an out-of-memory condition or IO error occurred during any prior 6670** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 6671** sqlite3_backup_finish() returns the corresponding [error code]. 6672** 6673** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 6674** is not a permanent error and does not affect the return value of 6675** sqlite3_backup_finish(). 6676** 6677** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]] 6678** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 6679** 6680** ^Each call to sqlite3_backup_step() sets two values inside 6681** the [sqlite3_backup] object: the number of pages still to be backed 6682** up and the total number of pages in the source database file. 6683** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 6684** retrieve these two values, respectively. 6685** 6686** ^The values returned by these functions are only updated by 6687** sqlite3_backup_step(). ^If the source database is modified during a backup 6688** operation, then the values are not updated to account for any extra 6689** pages that need to be updated or the size of the source database file 6690** changing. 6691** 6692** <b>Concurrent Usage of Database Handles</b> 6693** 6694** ^The source [database connection] may be used by the application for other 6695** purposes while a backup operation is underway or being initialized. 6696** ^If SQLite is compiled and configured to support threadsafe database 6697** connections, then the source database connection may be used concurrently 6698** from within other threads. 6699** 6700** However, the application must guarantee that the destination 6701** [database connection] is not passed to any other API (by any thread) after 6702** sqlite3_backup_init() is called and before the corresponding call to 6703** sqlite3_backup_finish(). SQLite does not currently check to see 6704** if the application incorrectly accesses the destination [database connection] 6705** and so no error code is reported, but the operations may malfunction 6706** nevertheless. Use of the destination database connection while a 6707** backup is in progress might also also cause a mutex deadlock. 6708** 6709** If running in [shared cache mode], the application must 6710** guarantee that the shared cache used by the destination database 6711** is not accessed while the backup is running. In practice this means 6712** that the application must guarantee that the disk file being 6713** backed up to is not accessed by any connection within the process, 6714** not just the specific connection that was passed to sqlite3_backup_init(). 6715** 6716** The [sqlite3_backup] object itself is partially threadsafe. Multiple 6717** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 6718** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 6719** APIs are not strictly speaking threadsafe. If they are invoked at the 6720** same time as another thread is invoking sqlite3_backup_step() it is 6721** possible that they return invalid values. 6722*/ 6723sqlite3_backup *sqlite3_backup_init( 6724 sqlite3 *pDest, /* Destination database handle */ 6725 const char *zDestName, /* Destination database name */ 6726 sqlite3 *pSource, /* Source database handle */ 6727 const char *zSourceName /* Source database name */ 6728); 6729int sqlite3_backup_step(sqlite3_backup *p, int nPage); 6730int sqlite3_backup_finish(sqlite3_backup *p); 6731int sqlite3_backup_remaining(sqlite3_backup *p); 6732int sqlite3_backup_pagecount(sqlite3_backup *p); 6733 6734/* 6735** CAPI3REF: Unlock Notification 6736** 6737** ^When running in shared-cache mode, a database operation may fail with 6738** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 6739** individual tables within the shared-cache cannot be obtained. See 6740** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 6741** ^This API may be used to register a callback that SQLite will invoke 6742** when the connection currently holding the required lock relinquishes it. 6743** ^This API is only available if the library was compiled with the 6744** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 6745** 6746** See Also: [Using the SQLite Unlock Notification Feature]. 6747** 6748** ^Shared-cache locks are released when a database connection concludes 6749** its current transaction, either by committing it or rolling it back. 6750** 6751** ^When a connection (known as the blocked connection) fails to obtain a 6752** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 6753** identity of the database connection (the blocking connection) that 6754** has locked the required resource is stored internally. ^After an 6755** application receives an SQLITE_LOCKED error, it may call the 6756** sqlite3_unlock_notify() method with the blocked connection handle as 6757** the first argument to register for a callback that will be invoked 6758** when the blocking connections current transaction is concluded. ^The 6759** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 6760** call that concludes the blocking connections transaction. 6761** 6762** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 6763** there is a chance that the blocking connection will have already 6764** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 6765** If this happens, then the specified callback is invoked immediately, 6766** from within the call to sqlite3_unlock_notify().)^ 6767** 6768** ^If the blocked connection is attempting to obtain a write-lock on a 6769** shared-cache table, and more than one other connection currently holds 6770** a read-lock on the same table, then SQLite arbitrarily selects one of 6771** the other connections to use as the blocking connection. 6772** 6773** ^(There may be at most one unlock-notify callback registered by a 6774** blocked connection. If sqlite3_unlock_notify() is called when the 6775** blocked connection already has a registered unlock-notify callback, 6776** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 6777** called with a NULL pointer as its second argument, then any existing 6778** unlock-notify callback is canceled. ^The blocked connections 6779** unlock-notify callback may also be canceled by closing the blocked 6780** connection using [sqlite3_close()]. 6781** 6782** The unlock-notify callback is not reentrant. If an application invokes 6783** any sqlite3_xxx API functions from within an unlock-notify callback, a 6784** crash or deadlock may be the result. 6785** 6786** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 6787** returns SQLITE_OK. 6788** 6789** <b>Callback Invocation Details</b> 6790** 6791** When an unlock-notify callback is registered, the application provides a 6792** single void* pointer that is passed to the callback when it is invoked. 6793** However, the signature of the callback function allows SQLite to pass 6794** it an array of void* context pointers. The first argument passed to 6795** an unlock-notify callback is a pointer to an array of void* pointers, 6796** and the second is the number of entries in the array. 6797** 6798** When a blocking connections transaction is concluded, there may be 6799** more than one blocked connection that has registered for an unlock-notify 6800** callback. ^If two or more such blocked connections have specified the 6801** same callback function, then instead of invoking the callback function 6802** multiple times, it is invoked once with the set of void* context pointers 6803** specified by the blocked connections bundled together into an array. 6804** This gives the application an opportunity to prioritize any actions 6805** related to the set of unblocked database connections. 6806** 6807** <b>Deadlock Detection</b> 6808** 6809** Assuming that after registering for an unlock-notify callback a 6810** database waits for the callback to be issued before taking any further 6811** action (a reasonable assumption), then using this API may cause the 6812** application to deadlock. For example, if connection X is waiting for 6813** connection Y's transaction to be concluded, and similarly connection 6814** Y is waiting on connection X's transaction, then neither connection 6815** will proceed and the system may remain deadlocked indefinitely. 6816** 6817** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 6818** detection. ^If a given call to sqlite3_unlock_notify() would put the 6819** system in a deadlocked state, then SQLITE_LOCKED is returned and no 6820** unlock-notify callback is registered. The system is said to be in 6821** a deadlocked state if connection A has registered for an unlock-notify 6822** callback on the conclusion of connection B's transaction, and connection 6823** B has itself registered for an unlock-notify callback when connection 6824** A's transaction is concluded. ^Indirect deadlock is also detected, so 6825** the system is also considered to be deadlocked if connection B has 6826** registered for an unlock-notify callback on the conclusion of connection 6827** C's transaction, where connection C is waiting on connection A. ^Any 6828** number of levels of indirection are allowed. 6829** 6830** <b>The "DROP TABLE" Exception</b> 6831** 6832** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 6833** always appropriate to call sqlite3_unlock_notify(). There is however, 6834** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 6835** SQLite checks if there are any currently executing SELECT statements 6836** that belong to the same connection. If there are, SQLITE_LOCKED is 6837** returned. In this case there is no "blocking connection", so invoking 6838** sqlite3_unlock_notify() results in the unlock-notify callback being 6839** invoked immediately. If the application then re-attempts the "DROP TABLE" 6840** or "DROP INDEX" query, an infinite loop might be the result. 6841** 6842** One way around this problem is to check the extended error code returned 6843** by an sqlite3_step() call. ^(If there is a blocking connection, then the 6844** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 6845** the special "DROP TABLE/INDEX" case, the extended error code is just 6846** SQLITE_LOCKED.)^ 6847*/ 6848int sqlite3_unlock_notify( 6849 sqlite3 *pBlocked, /* Waiting connection */ 6850 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 6851 void *pNotifyArg /* Argument to pass to xNotify */ 6852); 6853 6854 6855/* 6856** CAPI3REF: String Comparison 6857** 6858** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 6859** and extensions to compare the contents of two buffers containing UTF-8 6860** strings in a case-independent fashion, using the same definition of "case 6861** independence" that SQLite uses internally when comparing identifiers. 6862*/ 6863int sqlite3_stricmp(const char *, const char *); 6864int sqlite3_strnicmp(const char *, const char *, int); 6865 6866/* 6867** CAPI3REF: String Globbing 6868* 6869** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches 6870** the glob pattern P, and it returns non-zero if string X does not match 6871** the glob pattern P. ^The definition of glob pattern matching used in 6872** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 6873** SQL dialect used by SQLite. ^The sqlite3_strglob(P,X) function is case 6874** sensitive. 6875** 6876** Note that this routine returns zero on a match and non-zero if the strings 6877** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 6878*/ 6879int sqlite3_strglob(const char *zGlob, const char *zStr); 6880 6881/* 6882** CAPI3REF: Error Logging Interface 6883** 6884** ^The [sqlite3_log()] interface writes a message into the [error log] 6885** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 6886** ^If logging is enabled, the zFormat string and subsequent arguments are 6887** used with [sqlite3_snprintf()] to generate the final output string. 6888** 6889** The sqlite3_log() interface is intended for use by extensions such as 6890** virtual tables, collating functions, and SQL functions. While there is 6891** nothing to prevent an application from calling sqlite3_log(), doing so 6892** is considered bad form. 6893** 6894** The zFormat string must not be NULL. 6895** 6896** To avoid deadlocks and other threading problems, the sqlite3_log() routine 6897** will not use dynamically allocated memory. The log message is stored in 6898** a fixed-length buffer on the stack. If the log message is longer than 6899** a few hundred characters, it will be truncated to the length of the 6900** buffer. 6901*/ 6902void sqlite3_log(int iErrCode, const char *zFormat, ...); 6903 6904/* 6905** CAPI3REF: Write-Ahead Log Commit Hook 6906** 6907** ^The [sqlite3_wal_hook()] function is used to register a callback that 6908** will be invoked each time a database connection commits data to a 6909** [write-ahead log] (i.e. whenever a transaction is committed in 6910** [journal_mode | journal_mode=WAL mode]). 6911** 6912** ^The callback is invoked by SQLite after the commit has taken place and 6913** the associated write-lock on the database released, so the implementation 6914** may read, write or [checkpoint] the database as required. 6915** 6916** ^The first parameter passed to the callback function when it is invoked 6917** is a copy of the third parameter passed to sqlite3_wal_hook() when 6918** registering the callback. ^The second is a copy of the database handle. 6919** ^The third parameter is the name of the database that was written to - 6920** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 6921** is the number of pages currently in the write-ahead log file, 6922** including those that were just committed. 6923** 6924** The callback function should normally return [SQLITE_OK]. ^If an error 6925** code is returned, that error will propagate back up through the 6926** SQLite code base to cause the statement that provoked the callback 6927** to report an error, though the commit will have still occurred. If the 6928** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 6929** that does not correspond to any valid SQLite error code, the results 6930** are undefined. 6931** 6932** A single database handle may have at most a single write-ahead log callback 6933** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 6934** previously registered write-ahead log callback. ^Note that the 6935** [sqlite3_wal_autocheckpoint()] interface and the 6936** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 6937** those overwrite any prior [sqlite3_wal_hook()] settings. 6938*/ 6939void *sqlite3_wal_hook( 6940 sqlite3*, 6941 int(*)(void *,sqlite3*,const char*,int), 6942 void* 6943); 6944 6945/* 6946** CAPI3REF: Configure an auto-checkpoint 6947** 6948** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 6949** [sqlite3_wal_hook()] that causes any database on [database connection] D 6950** to automatically [checkpoint] 6951** after committing a transaction if there are N or 6952** more frames in the [write-ahead log] file. ^Passing zero or 6953** a negative value as the nFrame parameter disables automatic 6954** checkpoints entirely. 6955** 6956** ^The callback registered by this function replaces any existing callback 6957** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 6958** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 6959** configured by this function. 6960** 6961** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 6962** from SQL. 6963** 6964** ^Every new [database connection] defaults to having the auto-checkpoint 6965** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 6966** pages. The use of this interface 6967** is only necessary if the default setting is found to be suboptimal 6968** for a particular application. 6969*/ 6970int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 6971 6972/* 6973** CAPI3REF: Checkpoint a database 6974** 6975** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 6976** on [database connection] D to be [checkpointed]. ^If X is NULL or an 6977** empty string, then a checkpoint is run on all databases of 6978** connection D. ^If the database connection D is not in 6979** [WAL | write-ahead log mode] then this interface is a harmless no-op. 6980** 6981** ^The [wal_checkpoint pragma] can be used to invoke this interface 6982** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 6983** [wal_autocheckpoint pragma] can be used to cause this interface to be 6984** run whenever the WAL reaches a certain size threshold. 6985** 6986** See also: [sqlite3_wal_checkpoint_v2()] 6987*/ 6988int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 6989 6990/* 6991** CAPI3REF: Checkpoint a database 6992** 6993** Run a checkpoint operation on WAL database zDb attached to database 6994** handle db. The specific operation is determined by the value of the 6995** eMode parameter: 6996** 6997** <dl> 6998** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 6999** Checkpoint as many frames as possible without waiting for any database 7000** readers or writers to finish. Sync the db file if all frames in the log 7001** are checkpointed. This mode is the same as calling 7002** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked. 7003** 7004** <dt>SQLITE_CHECKPOINT_FULL<dd> 7005** This mode blocks (calls the busy-handler callback) until there is no 7006** database writer and all readers are reading from the most recent database 7007** snapshot. It then checkpoints all frames in the log file and syncs the 7008** database file. This call blocks database writers while it is running, 7009** but not database readers. 7010** 7011** <dt>SQLITE_CHECKPOINT_RESTART<dd> 7012** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after 7013** checkpointing the log file it blocks (calls the busy-handler callback) 7014** until all readers are reading from the database file only. This ensures 7015** that the next client to write to the database file restarts the log file 7016** from the beginning. This call blocks database writers while it is running, 7017** but not database readers. 7018** </dl> 7019** 7020** If pnLog is not NULL, then *pnLog is set to the total number of frames in 7021** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to 7022** the total number of checkpointed frames (including any that were already 7023** checkpointed when this function is called). *pnLog and *pnCkpt may be 7024** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK. 7025** If no values are available because of an error, they are both set to -1 7026** before returning to communicate this to the caller. 7027** 7028** All calls obtain an exclusive "checkpoint" lock on the database file. If 7029** any other process is running a checkpoint operation at the same time, the 7030** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a 7031** busy-handler configured, it will not be invoked in this case. 7032** 7033** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive 7034** "writer" lock on the database file. If the writer lock cannot be obtained 7035** immediately, and a busy-handler is configured, it is invoked and the writer 7036** lock retried until either the busy-handler returns 0 or the lock is 7037** successfully obtained. The busy-handler is also invoked while waiting for 7038** database readers as described above. If the busy-handler returns 0 before 7039** the writer lock is obtained or while waiting for database readers, the 7040** checkpoint operation proceeds from that point in the same way as 7041** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 7042** without blocking any further. SQLITE_BUSY is returned in this case. 7043** 7044** If parameter zDb is NULL or points to a zero length string, then the 7045** specified operation is attempted on all WAL databases. In this case the 7046** values written to output parameters *pnLog and *pnCkpt are undefined. If 7047** an SQLITE_BUSY error is encountered when processing one or more of the 7048** attached WAL databases, the operation is still attempted on any remaining 7049** attached databases and SQLITE_BUSY is returned to the caller. If any other 7050** error occurs while processing an attached database, processing is abandoned 7051** and the error code returned to the caller immediately. If no error 7052** (SQLITE_BUSY or otherwise) is encountered while processing the attached 7053** databases, SQLITE_OK is returned. 7054** 7055** If database zDb is the name of an attached database that is not in WAL 7056** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If 7057** zDb is not NULL (or a zero length string) and is not the name of any 7058** attached database, SQLITE_ERROR is returned to the caller. 7059*/ 7060int sqlite3_wal_checkpoint_v2( 7061 sqlite3 *db, /* Database handle */ 7062 const char *zDb, /* Name of attached database (or NULL) */ 7063 int eMode, /* SQLITE_CHECKPOINT_* value */ 7064 int *pnLog, /* OUT: Size of WAL log in frames */ 7065 int *pnCkpt /* OUT: Total number of frames checkpointed */ 7066); 7067 7068/* 7069** CAPI3REF: Checkpoint operation parameters 7070** 7071** These constants can be used as the 3rd parameter to 7072** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()] 7073** documentation for additional information about the meaning and use of 7074** each of these values. 7075*/ 7076#define SQLITE_CHECKPOINT_PASSIVE 0 7077#define SQLITE_CHECKPOINT_FULL 1 7078#define SQLITE_CHECKPOINT_RESTART 2 7079 7080/* 7081** CAPI3REF: Virtual Table Interface Configuration 7082** 7083** This function may be called by either the [xConnect] or [xCreate] method 7084** of a [virtual table] implementation to configure 7085** various facets of the virtual table interface. 7086** 7087** If this interface is invoked outside the context of an xConnect or 7088** xCreate virtual table method then the behavior is undefined. 7089** 7090** At present, there is only one option that may be configured using 7091** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 7092** may be added in the future. 7093*/ 7094int sqlite3_vtab_config(sqlite3*, int op, ...); 7095 7096/* 7097** CAPI3REF: Virtual Table Configuration Options 7098** 7099** These macros define the various options to the 7100** [sqlite3_vtab_config()] interface that [virtual table] implementations 7101** can use to customize and optimize their behavior. 7102** 7103** <dl> 7104** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 7105** <dd>Calls of the form 7106** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 7107** where X is an integer. If X is zero, then the [virtual table] whose 7108** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 7109** support constraints. In this configuration (which is the default) if 7110** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 7111** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 7112** specified as part of the users SQL statement, regardless of the actual 7113** ON CONFLICT mode specified. 7114** 7115** If X is non-zero, then the virtual table implementation guarantees 7116** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 7117** any modifications to internal or persistent data structures have been made. 7118** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 7119** is able to roll back a statement or database transaction, and abandon 7120** or continue processing the current SQL statement as appropriate. 7121** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 7122** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 7123** had been ABORT. 7124** 7125** Virtual table implementations that are required to handle OR REPLACE 7126** must do so within the [xUpdate] method. If a call to the 7127** [sqlite3_vtab_on_conflict()] function indicates that the current ON 7128** CONFLICT policy is REPLACE, the virtual table implementation should 7129** silently replace the appropriate rows within the xUpdate callback and 7130** return SQLITE_OK. Or, if this is not possible, it may return 7131** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 7132** constraint handling. 7133** </dl> 7134*/ 7135#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 7136 7137/* 7138** CAPI3REF: Determine The Virtual Table Conflict Policy 7139** 7140** This function may only be called from within a call to the [xUpdate] method 7141** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 7142** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 7143** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 7144** of the SQL statement that triggered the call to the [xUpdate] method of the 7145** [virtual table]. 7146*/ 7147int sqlite3_vtab_on_conflict(sqlite3 *); 7148 7149/* 7150** CAPI3REF: Conflict resolution modes 7151** 7152** These constants are returned by [sqlite3_vtab_on_conflict()] to 7153** inform a [virtual table] implementation what the [ON CONFLICT] mode 7154** is for the SQL statement being evaluated. 7155** 7156** Note that the [SQLITE_IGNORE] constant is also used as a potential 7157** return value from the [sqlite3_set_authorizer()] callback and that 7158** [SQLITE_ABORT] is also a [result code]. 7159*/ 7160#define SQLITE_ROLLBACK 1 7161/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 7162#define SQLITE_FAIL 3 7163/* #define SQLITE_ABORT 4 // Also an error code */ 7164#define SQLITE_REPLACE 5 7165 7166 7167 7168/* 7169** Undo the hack that converts floating point types to integer for 7170** builds on processors without floating point support. 7171*/ 7172#ifdef SQLITE_OMIT_FLOATING_POINT 7173# undef double 7174#endif 7175 7176#ifdef __cplusplus 7177} /* End of the 'extern "C"' block */ 7178#endif 7179#endif 7180