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