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_LIMIT]] 896** The [SQLITE_FCNTL_MMAP_LIMIT] 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 originally pointed to is negative, and so the current limit can be 902** queried by passing in a pointer to a negative number. This file-control 903** is used internally to implement [PRAGMA mmap_limit]. 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_LIMIT 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_LIMIT]] 1654** <dt>SQLITE_CONFIG_MMAP_LIMIT 1655** <dd>The sole argument should be a 64-bit integer (an sqlite3_int64) that 1656** is the default maximum number of bytes of process address space that 1657** should be used for accessing each database file using memory mapping. 1658** The default setting can be overridden by each database connection using 1659** either the [PRAGMA mmap_limit] command, or by using the 1660** [SQLITE_FCNTL_MMAP_LIMIT] file control. The value set here overrides the 1661** compile-time default that is set using [SQLITE_DEFAULT_MMAP_LIMIT]. 1662** If the argument to this option is negative, then 1663** the memory map limit is set to the compile-time default. 1664** </dl> 1665*/ 1666#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1667#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1668#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1669#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1670#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1671#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1672#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1673#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1674#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1675#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1676#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1677/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1678#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1679#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1680#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1681#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1682#define SQLITE_CONFIG_URI 17 /* int */ 1683#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1684#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1685#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1686#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1687#define SQLITE_CONFIG_MMAP_LIMIT 22 /* sqlite3_int64 */ 1688 1689/* 1690** CAPI3REF: Database Connection Configuration Options 1691** 1692** These constants are the available integer configuration options that 1693** can be passed as the second argument to the [sqlite3_db_config()] interface. 1694** 1695** New configuration options may be added in future releases of SQLite. 1696** Existing configuration options might be discontinued. Applications 1697** should check the return code from [sqlite3_db_config()] to make sure that 1698** the call worked. ^The [sqlite3_db_config()] interface will return a 1699** non-zero [error code] if a discontinued or unsupported configuration option 1700** is invoked. 1701** 1702** <dl> 1703** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1704** <dd> ^This option takes three additional arguments that determine the 1705** [lookaside memory allocator] configuration for the [database connection]. 1706** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1707** pointer to a memory buffer to use for lookaside memory. 1708** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1709** may be NULL in which case SQLite will allocate the 1710** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1711** size of each lookaside buffer slot. ^The third argument is the number of 1712** slots. The size of the buffer in the first argument must be greater than 1713** or equal to the product of the second and third arguments. The buffer 1714** must be aligned to an 8-byte boundary. ^If the second argument to 1715** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1716** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1717** configuration for a database connection can only be changed when that 1718** connection is not currently using lookaside memory, or in other words 1719** when the "current value" returned by 1720** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1721** Any attempt to change the lookaside memory configuration when lookaside 1722** memory is in use leaves the configuration unchanged and returns 1723** [SQLITE_BUSY].)^</dd> 1724** 1725** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1726** <dd> ^This option is used to enable or disable the enforcement of 1727** [foreign key constraints]. There should be two additional arguments. 1728** The first argument is an integer which is 0 to disable FK enforcement, 1729** positive to enable FK enforcement or negative to leave FK enforcement 1730** unchanged. The second parameter is a pointer to an integer into which 1731** is written 0 or 1 to indicate whether FK enforcement is off or on 1732** following this call. The second parameter may be a NULL pointer, in 1733** which case the FK enforcement setting is not reported back. </dd> 1734** 1735** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1736** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1737** There should be two additional arguments. 1738** The first argument is an integer which is 0 to disable triggers, 1739** positive to enable triggers or negative to leave the setting unchanged. 1740** The second parameter is a pointer to an integer into which 1741** is written 0 or 1 to indicate whether triggers are disabled or enabled 1742** following this call. The second parameter may be a NULL pointer, in 1743** which case the trigger setting is not reported back. </dd> 1744** 1745** </dl> 1746*/ 1747#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1748#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1749#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1750 1751 1752/* 1753** CAPI3REF: Enable Or Disable Extended Result Codes 1754** 1755** ^The sqlite3_extended_result_codes() routine enables or disables the 1756** [extended result codes] feature of SQLite. ^The extended result 1757** codes are disabled by default for historical compatibility. 1758*/ 1759int sqlite3_extended_result_codes(sqlite3*, int onoff); 1760 1761/* 1762** CAPI3REF: Last Insert Rowid 1763** 1764** ^Each entry in an SQLite table has a unique 64-bit signed 1765** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1766** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1767** names are not also used by explicitly declared columns. ^If 1768** the table has a column of type [INTEGER PRIMARY KEY] then that column 1769** is another alias for the rowid. 1770** 1771** ^This routine returns the [rowid] of the most recent 1772** successful [INSERT] into the database from the [database connection] 1773** in the first argument. ^As of SQLite version 3.7.7, this routines 1774** records the last insert rowid of both ordinary tables and [virtual tables]. 1775** ^If no successful [INSERT]s 1776** have ever occurred on that database connection, zero is returned. 1777** 1778** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1779** method, then this routine will return the [rowid] of the inserted 1780** row as long as the trigger or virtual table method is running. 1781** But once the trigger or virtual table method ends, the value returned 1782** by this routine reverts to what it was before the trigger or virtual 1783** table method began.)^ 1784** 1785** ^An [INSERT] that fails due to a constraint violation is not a 1786** successful [INSERT] and does not change the value returned by this 1787** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1788** and INSERT OR ABORT make no changes to the return value of this 1789** routine when their insertion fails. ^(When INSERT OR REPLACE 1790** encounters a constraint violation, it does not fail. The 1791** INSERT continues to completion after deleting rows that caused 1792** the constraint problem so INSERT OR REPLACE will always change 1793** the return value of this interface.)^ 1794** 1795** ^For the purposes of this routine, an [INSERT] is considered to 1796** be successful even if it is subsequently rolled back. 1797** 1798** This function is accessible to SQL statements via the 1799** [last_insert_rowid() SQL function]. 1800** 1801** If a separate thread performs a new [INSERT] on the same 1802** database connection while the [sqlite3_last_insert_rowid()] 1803** function is running and thus changes the last insert [rowid], 1804** then the value returned by [sqlite3_last_insert_rowid()] is 1805** unpredictable and might not equal either the old or the new 1806** last insert [rowid]. 1807*/ 1808sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1809 1810/* 1811** CAPI3REF: Count The Number Of Rows Modified 1812** 1813** ^This function returns the number of database rows that were changed 1814** or inserted or deleted by the most recently completed SQL statement 1815** on the [database connection] specified by the first parameter. 1816** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1817** or [DELETE] statement are counted. Auxiliary changes caused by 1818** triggers or [foreign key actions] are not counted.)^ Use the 1819** [sqlite3_total_changes()] function to find the total number of changes 1820** including changes caused by triggers and foreign key actions. 1821** 1822** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1823** are not counted. Only real table changes are counted. 1824** 1825** ^(A "row change" is a change to a single row of a single table 1826** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1827** are changed as side effects of [REPLACE] constraint resolution, 1828** rollback, ABORT processing, [DROP TABLE], or by any other 1829** mechanisms do not count as direct row changes.)^ 1830** 1831** A "trigger context" is a scope of execution that begins and 1832** ends with the script of a [CREATE TRIGGER | trigger]. 1833** Most SQL statements are 1834** evaluated outside of any trigger. This is the "top level" 1835** trigger context. If a trigger fires from the top level, a 1836** new trigger context is entered for the duration of that one 1837** trigger. Subtriggers create subcontexts for their duration. 1838** 1839** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1840** not create a new trigger context. 1841** 1842** ^This function returns the number of direct row changes in the 1843** most recent INSERT, UPDATE, or DELETE statement within the same 1844** trigger context. 1845** 1846** ^Thus, when called from the top level, this function returns the 1847** number of changes in the most recent INSERT, UPDATE, or DELETE 1848** that also occurred at the top level. ^(Within the body of a trigger, 1849** the sqlite3_changes() interface can be called to find the number of 1850** changes in the most recently completed INSERT, UPDATE, or DELETE 1851** statement within the body of the same trigger. 1852** However, the number returned does not include changes 1853** caused by subtriggers since those have their own context.)^ 1854** 1855** See also the [sqlite3_total_changes()] interface, the 1856** [count_changes pragma], and the [changes() SQL function]. 1857** 1858** If a separate thread makes changes on the same database connection 1859** while [sqlite3_changes()] is running then the value returned 1860** is unpredictable and not meaningful. 1861*/ 1862int sqlite3_changes(sqlite3*); 1863 1864/* 1865** CAPI3REF: Total Number Of Rows Modified 1866** 1867** ^This function returns the number of row changes caused by [INSERT], 1868** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1869** ^(The count returned by sqlite3_total_changes() includes all changes 1870** from all [CREATE TRIGGER | trigger] contexts and changes made by 1871** [foreign key actions]. However, 1872** the count does not include changes used to implement [REPLACE] constraints, 1873** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1874** count does not include rows of views that fire an [INSTEAD OF trigger], 1875** though if the INSTEAD OF trigger makes changes of its own, those changes 1876** are counted.)^ 1877** ^The sqlite3_total_changes() function counts the changes as soon as 1878** the statement that makes them is completed (when the statement handle 1879** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1880** 1881** See also the [sqlite3_changes()] interface, the 1882** [count_changes pragma], and the [total_changes() SQL function]. 1883** 1884** If a separate thread makes changes on the same database connection 1885** while [sqlite3_total_changes()] is running then the value 1886** returned is unpredictable and not meaningful. 1887*/ 1888int sqlite3_total_changes(sqlite3*); 1889 1890/* 1891** CAPI3REF: Interrupt A Long-Running Query 1892** 1893** ^This function causes any pending database operation to abort and 1894** return at its earliest opportunity. This routine is typically 1895** called in response to a user action such as pressing "Cancel" 1896** or Ctrl-C where the user wants a long query operation to halt 1897** immediately. 1898** 1899** ^It is safe to call this routine from a thread different from the 1900** thread that is currently running the database operation. But it 1901** is not safe to call this routine with a [database connection] that 1902** is closed or might close before sqlite3_interrupt() returns. 1903** 1904** ^If an SQL operation is very nearly finished at the time when 1905** sqlite3_interrupt() is called, then it might not have an opportunity 1906** to be interrupted and might continue to completion. 1907** 1908** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1909** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1910** that is inside an explicit transaction, then the entire transaction 1911** will be rolled back automatically. 1912** 1913** ^The sqlite3_interrupt(D) call is in effect until all currently running 1914** SQL statements on [database connection] D complete. ^Any new SQL statements 1915** that are started after the sqlite3_interrupt() call and before the 1916** running statements reaches zero are interrupted as if they had been 1917** running prior to the sqlite3_interrupt() call. ^New SQL statements 1918** that are started after the running statement count reaches zero are 1919** not effected by the sqlite3_interrupt(). 1920** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1921** SQL statements is a no-op and has no effect on SQL statements 1922** that are started after the sqlite3_interrupt() call returns. 1923** 1924** If the database connection closes while [sqlite3_interrupt()] 1925** is running then bad things will likely happen. 1926*/ 1927void sqlite3_interrupt(sqlite3*); 1928 1929/* 1930** CAPI3REF: Determine If An SQL Statement Is Complete 1931** 1932** These routines are useful during command-line input to determine if the 1933** currently entered text seems to form a complete SQL statement or 1934** if additional input is needed before sending the text into 1935** SQLite for parsing. ^These routines return 1 if the input string 1936** appears to be a complete SQL statement. ^A statement is judged to be 1937** complete if it ends with a semicolon token and is not a prefix of a 1938** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1939** string literals or quoted identifier names or comments are not 1940** independent tokens (they are part of the token in which they are 1941** embedded) and thus do not count as a statement terminator. ^Whitespace 1942** and comments that follow the final semicolon are ignored. 1943** 1944** ^These routines return 0 if the statement is incomplete. ^If a 1945** memory allocation fails, then SQLITE_NOMEM is returned. 1946** 1947** ^These routines do not parse the SQL statements thus 1948** will not detect syntactically incorrect SQL. 1949** 1950** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1951** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1952** automatically by sqlite3_complete16(). If that initialization fails, 1953** then the return value from sqlite3_complete16() will be non-zero 1954** regardless of whether or not the input SQL is complete.)^ 1955** 1956** The input to [sqlite3_complete()] must be a zero-terminated 1957** UTF-8 string. 1958** 1959** The input to [sqlite3_complete16()] must be a zero-terminated 1960** UTF-16 string in native byte order. 1961*/ 1962int sqlite3_complete(const char *sql); 1963int sqlite3_complete16(const void *sql); 1964 1965/* 1966** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1967** 1968** ^This routine sets a callback function that might be invoked whenever 1969** an attempt is made to open a database table that another thread 1970** or process has locked. 1971** 1972** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1973** is returned immediately upon encountering the lock. ^If the busy callback 1974** is not NULL, then the callback might be invoked with two arguments. 1975** 1976** ^The first argument to the busy handler is a copy of the void* pointer which 1977** is the third argument to sqlite3_busy_handler(). ^The second argument to 1978** the busy handler callback is the number of times that the busy handler has 1979** been invoked for this locking event. ^If the 1980** busy callback returns 0, then no additional attempts are made to 1981** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1982** ^If the callback returns non-zero, then another attempt 1983** is made to open the database for reading and the cycle repeats. 1984** 1985** The presence of a busy handler does not guarantee that it will be invoked 1986** when there is lock contention. ^If SQLite determines that invoking the busy 1987** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1988** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1989** Consider a scenario where one process is holding a read lock that 1990** it is trying to promote to a reserved lock and 1991** a second process is holding a reserved lock that it is trying 1992** to promote to an exclusive lock. The first process cannot proceed 1993** because it is blocked by the second and the second process cannot 1994** proceed because it is blocked by the first. If both processes 1995** invoke the busy handlers, neither will make any progress. Therefore, 1996** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1997** will induce the first process to release its read lock and allow 1998** the second process to proceed. 1999** 2000** ^The default busy callback is NULL. 2001** 2002** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 2003** when SQLite is in the middle of a large transaction where all the 2004** changes will not fit into the in-memory cache. SQLite will 2005** already hold a RESERVED lock on the database file, but it needs 2006** to promote this lock to EXCLUSIVE so that it can spill cache 2007** pages into the database file without harm to concurrent 2008** readers. ^If it is unable to promote the lock, then the in-memory 2009** cache will be left in an inconsistent state and so the error 2010** code is promoted from the relatively benign [SQLITE_BUSY] to 2011** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 2012** forces an automatic rollback of the changes. See the 2013** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 2014** CorruptionFollowingBusyError</a> wiki page for a discussion of why 2015** this is important. 2016** 2017** ^(There can only be a single busy handler defined for each 2018** [database connection]. Setting a new busy handler clears any 2019** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2020** will also set or clear the busy handler. 2021** 2022** The busy callback should not take any actions which modify the 2023** database connection that invoked the busy handler. Any such actions 2024** result in undefined behavior. 2025** 2026** A busy handler must not close the database connection 2027** or [prepared statement] that invoked the busy handler. 2028*/ 2029int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 2030 2031/* 2032** CAPI3REF: Set A Busy Timeout 2033** 2034** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2035** for a specified amount of time when a table is locked. ^The handler 2036** will sleep multiple times until at least "ms" milliseconds of sleeping 2037** have accumulated. ^After at least "ms" milliseconds of sleeping, 2038** the handler returns 0 which causes [sqlite3_step()] to return 2039** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 2040** 2041** ^Calling this routine with an argument less than or equal to zero 2042** turns off all busy handlers. 2043** 2044** ^(There can only be a single busy handler for a particular 2045** [database connection] any any given moment. If another busy handler 2046** was defined (using [sqlite3_busy_handler()]) prior to calling 2047** this routine, that other busy handler is cleared.)^ 2048*/ 2049int sqlite3_busy_timeout(sqlite3*, int ms); 2050 2051/* 2052** CAPI3REF: Convenience Routines For Running Queries 2053** 2054** This is a legacy interface that is preserved for backwards compatibility. 2055** Use of this interface is not recommended. 2056** 2057** Definition: A <b>result table</b> is memory data structure created by the 2058** [sqlite3_get_table()] interface. A result table records the 2059** complete query results from one or more queries. 2060** 2061** The table conceptually has a number of rows and columns. But 2062** these numbers are not part of the result table itself. These 2063** numbers are obtained separately. Let N be the number of rows 2064** and M be the number of columns. 2065** 2066** A result table is an array of pointers to zero-terminated UTF-8 strings. 2067** There are (N+1)*M elements in the array. The first M pointers point 2068** to zero-terminated strings that contain the names of the columns. 2069** The remaining entries all point to query results. NULL values result 2070** in NULL pointers. All other values are in their UTF-8 zero-terminated 2071** string representation as returned by [sqlite3_column_text()]. 2072** 2073** A result table might consist of one or more memory allocations. 2074** It is not safe to pass a result table directly to [sqlite3_free()]. 2075** A result table should be deallocated using [sqlite3_free_table()]. 2076** 2077** ^(As an example of the result table format, suppose a query result 2078** is as follows: 2079** 2080** <blockquote><pre> 2081** Name | Age 2082** ----------------------- 2083** Alice | 43 2084** Bob | 28 2085** Cindy | 21 2086** </pre></blockquote> 2087** 2088** There are two column (M==2) and three rows (N==3). Thus the 2089** result table has 8 entries. Suppose the result table is stored 2090** in an array names azResult. Then azResult holds this content: 2091** 2092** <blockquote><pre> 2093** azResult[0] = "Name"; 2094** azResult[1] = "Age"; 2095** azResult[2] = "Alice"; 2096** azResult[3] = "43"; 2097** azResult[4] = "Bob"; 2098** azResult[5] = "28"; 2099** azResult[6] = "Cindy"; 2100** azResult[7] = "21"; 2101** </pre></blockquote>)^ 2102** 2103** ^The sqlite3_get_table() function evaluates one or more 2104** semicolon-separated SQL statements in the zero-terminated UTF-8 2105** string of its 2nd parameter and returns a result table to the 2106** pointer given in its 3rd parameter. 2107** 2108** After the application has finished with the result from sqlite3_get_table(), 2109** it must pass the result table pointer to sqlite3_free_table() in order to 2110** release the memory that was malloced. Because of the way the 2111** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2112** function must not try to call [sqlite3_free()] directly. Only 2113** [sqlite3_free_table()] is able to release the memory properly and safely. 2114** 2115** The sqlite3_get_table() interface is implemented as a wrapper around 2116** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2117** to any internal data structures of SQLite. It uses only the public 2118** interface defined here. As a consequence, errors that occur in the 2119** wrapper layer outside of the internal [sqlite3_exec()] call are not 2120** reflected in subsequent calls to [sqlite3_errcode()] or 2121** [sqlite3_errmsg()]. 2122*/ 2123int sqlite3_get_table( 2124 sqlite3 *db, /* An open database */ 2125 const char *zSql, /* SQL to be evaluated */ 2126 char ***pazResult, /* Results of the query */ 2127 int *pnRow, /* Number of result rows written here */ 2128 int *pnColumn, /* Number of result columns written here */ 2129 char **pzErrmsg /* Error msg written here */ 2130); 2131void sqlite3_free_table(char **result); 2132 2133/* 2134** CAPI3REF: Formatted String Printing Functions 2135** 2136** These routines are work-alikes of the "printf()" family of functions 2137** from the standard C library. 2138** 2139** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2140** results into memory obtained from [sqlite3_malloc()]. 2141** The strings returned by these two routines should be 2142** released by [sqlite3_free()]. ^Both routines return a 2143** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2144** memory to hold the resulting string. 2145** 2146** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2147** the standard C library. The result is written into the 2148** buffer supplied as the second parameter whose size is given by 2149** the first parameter. Note that the order of the 2150** first two parameters is reversed from snprintf().)^ This is an 2151** historical accident that cannot be fixed without breaking 2152** backwards compatibility. ^(Note also that sqlite3_snprintf() 2153** returns a pointer to its buffer instead of the number of 2154** characters actually written into the buffer.)^ We admit that 2155** the number of characters written would be a more useful return 2156** value but we cannot change the implementation of sqlite3_snprintf() 2157** now without breaking compatibility. 2158** 2159** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2160** guarantees that the buffer is always zero-terminated. ^The first 2161** parameter "n" is the total size of the buffer, including space for 2162** the zero terminator. So the longest string that can be completely 2163** written will be n-1 characters. 2164** 2165** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2166** 2167** These routines all implement some additional formatting 2168** options that are useful for constructing SQL statements. 2169** All of the usual printf() formatting options apply. In addition, there 2170** is are "%q", "%Q", and "%z" options. 2171** 2172** ^(The %q option works like %s in that it substitutes a nul-terminated 2173** string from the argument list. But %q also doubles every '\'' character. 2174** %q is designed for use inside a string literal.)^ By doubling each '\'' 2175** character it escapes that character and allows it to be inserted into 2176** the string. 2177** 2178** For example, assume the string variable zText contains text as follows: 2179** 2180** <blockquote><pre> 2181** char *zText = "It's a happy day!"; 2182** </pre></blockquote> 2183** 2184** One can use this text in an SQL statement as follows: 2185** 2186** <blockquote><pre> 2187** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2188** sqlite3_exec(db, zSQL, 0, 0, 0); 2189** sqlite3_free(zSQL); 2190** </pre></blockquote> 2191** 2192** Because the %q format string is used, the '\'' character in zText 2193** is escaped and the SQL generated is as follows: 2194** 2195** <blockquote><pre> 2196** INSERT INTO table1 VALUES('It''s a happy day!') 2197** </pre></blockquote> 2198** 2199** This is correct. Had we used %s instead of %q, the generated SQL 2200** would have looked like this: 2201** 2202** <blockquote><pre> 2203** INSERT INTO table1 VALUES('It's a happy day!'); 2204** </pre></blockquote> 2205** 2206** This second example is an SQL syntax error. As a general rule you should 2207** always use %q instead of %s when inserting text into a string literal. 2208** 2209** ^(The %Q option works like %q except it also adds single quotes around 2210** the outside of the total string. Additionally, if the parameter in the 2211** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2212** single quotes).)^ So, for example, one could say: 2213** 2214** <blockquote><pre> 2215** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2216** sqlite3_exec(db, zSQL, 0, 0, 0); 2217** sqlite3_free(zSQL); 2218** </pre></blockquote> 2219** 2220** The code above will render a correct SQL statement in the zSQL 2221** variable even if the zText variable is a NULL pointer. 2222** 2223** ^(The "%z" formatting option works like "%s" but with the 2224** addition that after the string has been read and copied into 2225** the result, [sqlite3_free()] is called on the input string.)^ 2226*/ 2227char *sqlite3_mprintf(const char*,...); 2228char *sqlite3_vmprintf(const char*, va_list); 2229char *sqlite3_snprintf(int,char*,const char*, ...); 2230char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2231 2232/* 2233** CAPI3REF: Memory Allocation Subsystem 2234** 2235** The SQLite core uses these three routines for all of its own 2236** internal memory allocation needs. "Core" in the previous sentence 2237** does not include operating-system specific VFS implementation. The 2238** Windows VFS uses native malloc() and free() for some operations. 2239** 2240** ^The sqlite3_malloc() routine returns a pointer to a block 2241** of memory at least N bytes in length, where N is the parameter. 2242** ^If sqlite3_malloc() is unable to obtain sufficient free 2243** memory, it returns a NULL pointer. ^If the parameter N to 2244** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2245** a NULL pointer. 2246** 2247** ^Calling sqlite3_free() with a pointer previously returned 2248** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2249** that it might be reused. ^The sqlite3_free() routine is 2250** a no-op if is called with a NULL pointer. Passing a NULL pointer 2251** to sqlite3_free() is harmless. After being freed, memory 2252** should neither be read nor written. Even reading previously freed 2253** memory might result in a segmentation fault or other severe error. 2254** Memory corruption, a segmentation fault, or other severe error 2255** might result if sqlite3_free() is called with a non-NULL pointer that 2256** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2257** 2258** ^(The sqlite3_realloc() interface attempts to resize a 2259** prior memory allocation to be at least N bytes, where N is the 2260** second parameter. The memory allocation to be resized is the first 2261** parameter.)^ ^ If the first parameter to sqlite3_realloc() 2262** is a NULL pointer then its behavior is identical to calling 2263** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 2264** ^If the second parameter to sqlite3_realloc() is zero or 2265** negative then the behavior is exactly the same as calling 2266** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 2267** ^sqlite3_realloc() returns a pointer to a memory allocation 2268** of at least N bytes in size or NULL if sufficient memory is unavailable. 2269** ^If M is the size of the prior allocation, then min(N,M) bytes 2270** of the prior allocation are copied into the beginning of buffer returned 2271** by sqlite3_realloc() and the prior allocation is freed. 2272** ^If sqlite3_realloc() returns NULL, then the prior allocation 2273** is not freed. 2274** 2275** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 2276** is always aligned to at least an 8 byte boundary, or to a 2277** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2278** option is used. 2279** 2280** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2281** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2282** implementation of these routines to be omitted. That capability 2283** is no longer provided. Only built-in memory allocators can be used. 2284** 2285** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2286** the system malloc() and free() directly when converting 2287** filenames between the UTF-8 encoding used by SQLite 2288** and whatever filename encoding is used by the particular Windows 2289** installation. Memory allocation errors were detected, but 2290** they were reported back as [SQLITE_CANTOPEN] or 2291** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2292** 2293** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2294** must be either NULL or else pointers obtained from a prior 2295** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2296** not yet been released. 2297** 2298** The application must not read or write any part of 2299** a block of memory after it has been released using 2300** [sqlite3_free()] or [sqlite3_realloc()]. 2301*/ 2302void *sqlite3_malloc(int); 2303void *sqlite3_realloc(void*, int); 2304void sqlite3_free(void*); 2305 2306/* 2307** CAPI3REF: Memory Allocator Statistics 2308** 2309** SQLite provides these two interfaces for reporting on the status 2310** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2311** routines, which form the built-in memory allocation subsystem. 2312** 2313** ^The [sqlite3_memory_used()] routine returns the number of bytes 2314** of memory currently outstanding (malloced but not freed). 2315** ^The [sqlite3_memory_highwater()] routine returns the maximum 2316** value of [sqlite3_memory_used()] since the high-water mark 2317** was last reset. ^The values returned by [sqlite3_memory_used()] and 2318** [sqlite3_memory_highwater()] include any overhead 2319** added by SQLite in its implementation of [sqlite3_malloc()], 2320** but not overhead added by the any underlying system library 2321** routines that [sqlite3_malloc()] may call. 2322** 2323** ^The memory high-water mark is reset to the current value of 2324** [sqlite3_memory_used()] if and only if the parameter to 2325** [sqlite3_memory_highwater()] is true. ^The value returned 2326** by [sqlite3_memory_highwater(1)] is the high-water mark 2327** prior to the reset. 2328*/ 2329sqlite3_int64 sqlite3_memory_used(void); 2330sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2331 2332/* 2333** CAPI3REF: Pseudo-Random Number Generator 2334** 2335** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2336** select random [ROWID | ROWIDs] when inserting new records into a table that 2337** already uses the largest possible [ROWID]. The PRNG is also used for 2338** the build-in random() and randomblob() SQL functions. This interface allows 2339** applications to access the same PRNG for other purposes. 2340** 2341** ^A call to this routine stores N bytes of randomness into buffer P. 2342** 2343** ^The first time this routine is invoked (either internally or by 2344** the application) the PRNG is seeded using randomness obtained 2345** from the xRandomness method of the default [sqlite3_vfs] object. 2346** ^On all subsequent invocations, the pseudo-randomness is generated 2347** internally and without recourse to the [sqlite3_vfs] xRandomness 2348** method. 2349*/ 2350void sqlite3_randomness(int N, void *P); 2351 2352/* 2353** CAPI3REF: Compile-Time Authorization Callbacks 2354** 2355** ^This routine registers an authorizer callback with a particular 2356** [database connection], supplied in the first argument. 2357** ^The authorizer callback is invoked as SQL statements are being compiled 2358** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2359** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2360** points during the compilation process, as logic is being created 2361** to perform various actions, the authorizer callback is invoked to 2362** see if those actions are allowed. ^The authorizer callback should 2363** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2364** specific action but allow the SQL statement to continue to be 2365** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2366** rejected with an error. ^If the authorizer callback returns 2367** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2368** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2369** the authorizer will fail with an error message. 2370** 2371** When the callback returns [SQLITE_OK], that means the operation 2372** requested is ok. ^When the callback returns [SQLITE_DENY], the 2373** [sqlite3_prepare_v2()] or equivalent call that triggered the 2374** authorizer will fail with an error message explaining that 2375** access is denied. 2376** 2377** ^The first parameter to the authorizer callback is a copy of the third 2378** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2379** to the callback is an integer [SQLITE_COPY | action code] that specifies 2380** the particular action to be authorized. ^The third through sixth parameters 2381** to the callback are zero-terminated strings that contain additional 2382** details about the action to be authorized. 2383** 2384** ^If the action code is [SQLITE_READ] 2385** and the callback returns [SQLITE_IGNORE] then the 2386** [prepared statement] statement is constructed to substitute 2387** a NULL value in place of the table column that would have 2388** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2389** return can be used to deny an untrusted user access to individual 2390** columns of a table. 2391** ^If the action code is [SQLITE_DELETE] and the callback returns 2392** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2393** [truncate optimization] is disabled and all rows are deleted individually. 2394** 2395** An authorizer is used when [sqlite3_prepare | preparing] 2396** SQL statements from an untrusted source, to ensure that the SQL statements 2397** do not try to access data they are not allowed to see, or that they do not 2398** try to execute malicious statements that damage the database. For 2399** example, an application may allow a user to enter arbitrary 2400** SQL queries for evaluation by a database. But the application does 2401** not want the user to be able to make arbitrary changes to the 2402** database. An authorizer could then be put in place while the 2403** user-entered SQL is being [sqlite3_prepare | prepared] that 2404** disallows everything except [SELECT] statements. 2405** 2406** Applications that need to process SQL from untrusted sources 2407** might also consider lowering resource limits using [sqlite3_limit()] 2408** and limiting database size using the [max_page_count] [PRAGMA] 2409** in addition to using an authorizer. 2410** 2411** ^(Only a single authorizer can be in place on a database connection 2412** at a time. Each call to sqlite3_set_authorizer overrides the 2413** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2414** The authorizer is disabled by default. 2415** 2416** The authorizer callback must not do anything that will modify 2417** the database connection that invoked the authorizer callback. 2418** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2419** database connections for the meaning of "modify" in this paragraph. 2420** 2421** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2422** statement might be re-prepared during [sqlite3_step()] due to a 2423** schema change. Hence, the application should ensure that the 2424** correct authorizer callback remains in place during the [sqlite3_step()]. 2425** 2426** ^Note that the authorizer callback is invoked only during 2427** [sqlite3_prepare()] or its variants. Authorization is not 2428** performed during statement evaluation in [sqlite3_step()], unless 2429** as stated in the previous paragraph, sqlite3_step() invokes 2430** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2431*/ 2432int sqlite3_set_authorizer( 2433 sqlite3*, 2434 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2435 void *pUserData 2436); 2437 2438/* 2439** CAPI3REF: Authorizer Return Codes 2440** 2441** The [sqlite3_set_authorizer | authorizer callback function] must 2442** return either [SQLITE_OK] or one of these two constants in order 2443** to signal SQLite whether or not the action is permitted. See the 2444** [sqlite3_set_authorizer | authorizer documentation] for additional 2445** information. 2446** 2447** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code] 2448** from the [sqlite3_vtab_on_conflict()] interface. 2449*/ 2450#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2451#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2452 2453/* 2454** CAPI3REF: Authorizer Action Codes 2455** 2456** The [sqlite3_set_authorizer()] interface registers a callback function 2457** that is invoked to authorize certain SQL statement actions. The 2458** second parameter to the callback is an integer code that specifies 2459** what action is being authorized. These are the integer action codes that 2460** the authorizer callback may be passed. 2461** 2462** These action code values signify what kind of operation is to be 2463** authorized. The 3rd and 4th parameters to the authorization 2464** callback function will be parameters or NULL depending on which of these 2465** codes is used as the second parameter. ^(The 5th parameter to the 2466** authorizer callback is the name of the database ("main", "temp", 2467** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2468** is the name of the inner-most trigger or view that is responsible for 2469** the access attempt or NULL if this access attempt is directly from 2470** top-level SQL code. 2471*/ 2472/******************************************* 3rd ************ 4th ***********/ 2473#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2474#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2475#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2476#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2477#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2478#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2479#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2480#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2481#define SQLITE_DELETE 9 /* Table Name NULL */ 2482#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2483#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2484#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2485#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2486#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2487#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2488#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2489#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2490#define SQLITE_INSERT 18 /* Table Name NULL */ 2491#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2492#define SQLITE_READ 20 /* Table Name Column Name */ 2493#define SQLITE_SELECT 21 /* NULL NULL */ 2494#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2495#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2496#define SQLITE_ATTACH 24 /* Filename NULL */ 2497#define SQLITE_DETACH 25 /* Database Name NULL */ 2498#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2499#define SQLITE_REINDEX 27 /* Index Name NULL */ 2500#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2501#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2502#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2503#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2504#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2505#define SQLITE_COPY 0 /* No longer used */ 2506 2507/* 2508** CAPI3REF: Tracing And Profiling Functions 2509** 2510** These routines register callback functions that can be used for 2511** tracing and profiling the execution of SQL statements. 2512** 2513** ^The callback function registered by sqlite3_trace() is invoked at 2514** various times when an SQL statement is being run by [sqlite3_step()]. 2515** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2516** SQL statement text as the statement first begins executing. 2517** ^(Additional sqlite3_trace() callbacks might occur 2518** as each triggered subprogram is entered. The callbacks for triggers 2519** contain a UTF-8 SQL comment that identifies the trigger.)^ 2520** 2521** ^The callback function registered by sqlite3_profile() is invoked 2522** as each SQL statement finishes. ^The profile callback contains 2523** the original statement text and an estimate of wall-clock time 2524** of how long that statement took to run. ^The profile callback 2525** time is in units of nanoseconds, however the current implementation 2526** is only capable of millisecond resolution so the six least significant 2527** digits in the time are meaningless. Future versions of SQLite 2528** might provide greater resolution on the profiler callback. The 2529** sqlite3_profile() function is considered experimental and is 2530** subject to change in future versions of SQLite. 2531*/ 2532void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2533SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2534 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2535 2536/* 2537** CAPI3REF: Query Progress Callbacks 2538** 2539** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2540** function X to be invoked periodically during long running calls to 2541** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2542** database connection D. An example use for this 2543** interface is to keep a GUI updated during a large query. 2544** 2545** ^The parameter P is passed through as the only parameter to the 2546** callback function X. ^The parameter N is the number of 2547** [virtual machine instructions] that are evaluated between successive 2548** invocations of the callback X. 2549** 2550** ^Only a single progress handler may be defined at one time per 2551** [database connection]; setting a new progress handler cancels the 2552** old one. ^Setting parameter X to NULL disables the progress handler. 2553** ^The progress handler is also disabled by setting N to a value less 2554** than 1. 2555** 2556** ^If the progress callback returns non-zero, the operation is 2557** interrupted. This feature can be used to implement a 2558** "Cancel" button on a GUI progress dialog box. 2559** 2560** The progress handler callback must not do anything that will modify 2561** the database connection that invoked the progress handler. 2562** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2563** database connections for the meaning of "modify" in this paragraph. 2564** 2565*/ 2566void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2567 2568/* 2569** CAPI3REF: Opening A New Database Connection 2570** 2571** ^These routines open an SQLite database file as specified by the 2572** filename argument. ^The filename argument is interpreted as UTF-8 for 2573** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2574** order for sqlite3_open16(). ^(A [database connection] handle is usually 2575** returned in *ppDb, even if an error occurs. The only exception is that 2576** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2577** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2578** object.)^ ^(If the database is opened (and/or created) successfully, then 2579** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2580** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2581** an English language description of the error following a failure of any 2582** of the sqlite3_open() routines. 2583** 2584** ^The default encoding for the database will be UTF-8 if 2585** sqlite3_open() or sqlite3_open_v2() is called and 2586** UTF-16 in the native byte order if sqlite3_open16() is used. 2587** 2588** Whether or not an error occurs when it is opened, resources 2589** associated with the [database connection] handle should be released by 2590** passing it to [sqlite3_close()] when it is no longer required. 2591** 2592** The sqlite3_open_v2() interface works like sqlite3_open() 2593** except that it accepts two additional parameters for additional control 2594** over the new database connection. ^(The flags parameter to 2595** sqlite3_open_v2() can take one of 2596** the following three values, optionally combined with the 2597** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2598** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2599** 2600** <dl> 2601** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2602** <dd>The database is opened in read-only mode. If the database does not 2603** already exist, an error is returned.</dd>)^ 2604** 2605** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2606** <dd>The database is opened for reading and writing if possible, or reading 2607** only if the file is write protected by the operating system. In either 2608** case the database must already exist, otherwise an error is returned.</dd>)^ 2609** 2610** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2611** <dd>The database is opened for reading and writing, and is created if 2612** it does not already exist. This is the behavior that is always used for 2613** sqlite3_open() and sqlite3_open16().</dd>)^ 2614** </dl> 2615** 2616** If the 3rd parameter to sqlite3_open_v2() is not one of the 2617** combinations shown above optionally combined with other 2618** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2619** then the behavior is undefined. 2620** 2621** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2622** opens in the multi-thread [threading mode] as long as the single-thread 2623** mode has not been set at compile-time or start-time. ^If the 2624** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2625** in the serialized [threading mode] unless single-thread was 2626** previously selected at compile-time or start-time. 2627** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2628** eligible to use [shared cache mode], regardless of whether or not shared 2629** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2630** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2631** participate in [shared cache mode] even if it is enabled. 2632** 2633** ^The fourth parameter to sqlite3_open_v2() is the name of the 2634** [sqlite3_vfs] object that defines the operating system interface that 2635** the new database connection should use. ^If the fourth parameter is 2636** a NULL pointer then the default [sqlite3_vfs] object is used. 2637** 2638** ^If the filename is ":memory:", then a private, temporary in-memory database 2639** is created for the connection. ^This in-memory database will vanish when 2640** the database connection is closed. Future versions of SQLite might 2641** make use of additional special filenames that begin with the ":" character. 2642** It is recommended that when a database filename actually does begin with 2643** a ":" character you should prefix the filename with a pathname such as 2644** "./" to avoid ambiguity. 2645** 2646** ^If the filename is an empty string, then a private, temporary 2647** on-disk database will be created. ^This private database will be 2648** automatically deleted as soon as the database connection is closed. 2649** 2650** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2651** 2652** ^If [URI filename] interpretation is enabled, and the filename argument 2653** begins with "file:", then the filename is interpreted as a URI. ^URI 2654** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2655** set in the fourth argument to sqlite3_open_v2(), or if it has 2656** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2657** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2658** As of SQLite version 3.7.7, URI filename interpretation is turned off 2659** by default, but future releases of SQLite might enable URI filename 2660** interpretation by default. See "[URI filenames]" for additional 2661** information. 2662** 2663** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2664** authority, then it must be either an empty string or the string 2665** "localhost". ^If the authority is not an empty string or "localhost", an 2666** error is returned to the caller. ^The fragment component of a URI, if 2667** present, is ignored. 2668** 2669** ^SQLite uses the path component of the URI as the name of the disk file 2670** which contains the database. ^If the path begins with a '/' character, 2671** then it is interpreted as an absolute path. ^If the path does not begin 2672** with a '/' (meaning that the authority section is omitted from the URI) 2673** then the path is interpreted as a relative path. 2674** ^On windows, the first component of an absolute path 2675** is a drive specification (e.g. "C:"). 2676** 2677** [[core URI query parameters]] 2678** The query component of a URI may contain parameters that are interpreted 2679** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2680** SQLite interprets the following three query parameters: 2681** 2682** <ul> 2683** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2684** a VFS object that provides the operating system interface that should 2685** be used to access the database file on disk. ^If this option is set to 2686** an empty string the default VFS object is used. ^Specifying an unknown 2687** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2688** present, then the VFS specified by the option takes precedence over 2689** the value passed as the fourth parameter to sqlite3_open_v2(). 2690** 2691** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 2692** "rwc", or "memory". Attempting to set it to any other value is 2693** an error)^. 2694** ^If "ro" is specified, then the database is opened for read-only 2695** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2696** third argument to sqlite3_open_v2(). ^If the mode option is set to 2697** "rw", then the database is opened for read-write (but not create) 2698** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2699** been set. ^Value "rwc" is equivalent to setting both 2700** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 2701** set to "memory" then a pure [in-memory database] that never reads 2702** or writes from disk is used. ^It is an error to specify a value for 2703** the mode parameter that is less restrictive than that specified by 2704** the flags passed in the third parameter to sqlite3_open_v2(). 2705** 2706** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2707** "private". ^Setting it to "shared" is equivalent to setting the 2708** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2709** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2710** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2711** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2712** a URI filename, its value overrides any behavior requested by setting 2713** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2714** </ul> 2715** 2716** ^Specifying an unknown parameter in the query component of a URI is not an 2717** error. Future versions of SQLite might understand additional query 2718** parameters. See "[query parameters with special meaning to SQLite]" for 2719** additional information. 2720** 2721** [[URI filename examples]] <h3>URI filename examples</h3> 2722** 2723** <table border="1" align=center cellpadding=5> 2724** <tr><th> URI filenames <th> Results 2725** <tr><td> file:data.db <td> 2726** Open the file "data.db" in the current directory. 2727** <tr><td> file:/home/fred/data.db<br> 2728** file:///home/fred/data.db <br> 2729** file://localhost/home/fred/data.db <br> <td> 2730** Open the database file "/home/fred/data.db". 2731** <tr><td> file://darkstar/home/fred/data.db <td> 2732** An error. "darkstar" is not a recognized authority. 2733** <tr><td style="white-space:nowrap"> 2734** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2735** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2736** C:. Note that the %20 escaping in this example is not strictly 2737** necessary - space characters can be used literally 2738** in URI filenames. 2739** <tr><td> file:data.db?mode=ro&cache=private <td> 2740** Open file "data.db" in the current directory for read-only access. 2741** Regardless of whether or not shared-cache mode is enabled by 2742** default, use a private cache. 2743** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td> 2744** Open file "/home/fred/data.db". Use the special VFS "unix-nolock". 2745** <tr><td> file:data.db?mode=readonly <td> 2746** An error. "readonly" is not a valid option for the "mode" parameter. 2747** </table> 2748** 2749** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2750** query components of a URI. A hexadecimal escape sequence consists of a 2751** percent sign - "%" - followed by exactly two hexadecimal digits 2752** specifying an octet value. ^Before the path or query components of a 2753** URI filename are interpreted, they are encoded using UTF-8 and all 2754** hexadecimal escape sequences replaced by a single byte containing the 2755** corresponding octet. If this process generates an invalid UTF-8 encoding, 2756** the results are undefined. 2757** 2758** <b>Note to Windows users:</b> The encoding used for the filename argument 2759** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2760** codepage is currently defined. Filenames containing international 2761** characters must be converted to UTF-8 prior to passing them into 2762** sqlite3_open() or sqlite3_open_v2(). 2763** 2764** <b>Note to Windows Runtime users:</b> The temporary directory must be set 2765** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 2766** features that require the use of temporary files may fail. 2767** 2768** See also: [sqlite3_temp_directory] 2769*/ 2770int sqlite3_open( 2771 const char *filename, /* Database filename (UTF-8) */ 2772 sqlite3 **ppDb /* OUT: SQLite db handle */ 2773); 2774int sqlite3_open16( 2775 const void *filename, /* Database filename (UTF-16) */ 2776 sqlite3 **ppDb /* OUT: SQLite db handle */ 2777); 2778int sqlite3_open_v2( 2779 const char *filename, /* Database filename (UTF-8) */ 2780 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2781 int flags, /* Flags */ 2782 const char *zVfs /* Name of VFS module to use */ 2783); 2784 2785/* 2786** CAPI3REF: Obtain Values For URI Parameters 2787** 2788** These are utility routines, useful to VFS implementations, that check 2789** to see if a database file was a URI that contained a specific query 2790** parameter, and if so obtains the value of that query parameter. 2791** 2792** If F is the database filename pointer passed into the xOpen() method of 2793** a VFS implementation when the flags parameter to xOpen() has one or 2794** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 2795** P is the name of the query parameter, then 2796** sqlite3_uri_parameter(F,P) returns the value of the P 2797** parameter if it exists or a NULL pointer if P does not appear as a 2798** query parameter on F. If P is a query parameter of F 2799** has no explicit value, then sqlite3_uri_parameter(F,P) returns 2800** a pointer to an empty string. 2801** 2802** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 2803** parameter and returns true (1) or false (0) according to the value 2804** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 2805** value of query parameter P is one of "yes", "true", or "on" in any 2806** case or if the value begins with a non-zero number. The 2807** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 2808** query parameter P is one of "no", "false", or "off" in any case or 2809** if the value begins with a numeric zero. If P is not a query 2810** parameter on F or if the value of P is does not match any of the 2811** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 2812** 2813** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 2814** 64-bit signed integer and returns that integer, or D if P does not 2815** exist. If the value of P is something other than an integer, then 2816** zero is returned. 2817** 2818** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 2819** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 2820** is not a database file pathname pointer that SQLite passed into the xOpen 2821** VFS method, then the behavior of this routine is undefined and probably 2822** undesirable. 2823*/ 2824const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 2825int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 2826sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 2827 2828 2829/* 2830** CAPI3REF: Error Codes And Messages 2831** 2832** ^The sqlite3_errcode() interface returns the numeric [result code] or 2833** [extended result code] for the most recent failed sqlite3_* API call 2834** associated with a [database connection]. If a prior API call failed 2835** but the most recent API call succeeded, the return value from 2836** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2837** interface is the same except that it always returns the 2838** [extended result code] even when extended result codes are 2839** disabled. 2840** 2841** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2842** text that describes the error, as either UTF-8 or UTF-16 respectively. 2843** ^(Memory to hold the error message string is managed internally. 2844** The application does not need to worry about freeing the result. 2845** However, the error string might be overwritten or deallocated by 2846** subsequent calls to other SQLite interface functions.)^ 2847** 2848** ^The sqlite3_errstr() interface returns the English-language text 2849** that describes the [result code], as UTF-8. 2850** ^(Memory to hold the error message string is managed internally 2851** and must not be freed by the application)^. 2852** 2853** When the serialized [threading mode] is in use, it might be the 2854** case that a second error occurs on a separate thread in between 2855** the time of the first error and the call to these interfaces. 2856** When that happens, the second error will be reported since these 2857** interfaces always report the most recent result. To avoid 2858** this, each thread can obtain exclusive use of the [database connection] D 2859** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2860** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2861** all calls to the interfaces listed here are completed. 2862** 2863** If an interface fails with SQLITE_MISUSE, that means the interface 2864** was invoked incorrectly by the application. In that case, the 2865** error code and message may or may not be set. 2866*/ 2867int sqlite3_errcode(sqlite3 *db); 2868int sqlite3_extended_errcode(sqlite3 *db); 2869const char *sqlite3_errmsg(sqlite3*); 2870const void *sqlite3_errmsg16(sqlite3*); 2871const char *sqlite3_errstr(int); 2872 2873/* 2874** CAPI3REF: SQL Statement Object 2875** KEYWORDS: {prepared statement} {prepared statements} 2876** 2877** An instance of this object represents a single SQL statement. 2878** This object is variously known as a "prepared statement" or a 2879** "compiled SQL statement" or simply as a "statement". 2880** 2881** The life of a statement object goes something like this: 2882** 2883** <ol> 2884** <li> Create the object using [sqlite3_prepare_v2()] or a related 2885** function. 2886** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2887** interfaces. 2888** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2889** <li> Reset the statement using [sqlite3_reset()] then go back 2890** to step 2. Do this zero or more times. 2891** <li> Destroy the object using [sqlite3_finalize()]. 2892** </ol> 2893** 2894** Refer to documentation on individual methods above for additional 2895** information. 2896*/ 2897typedef struct sqlite3_stmt sqlite3_stmt; 2898 2899/* 2900** CAPI3REF: Run-time Limits 2901** 2902** ^(This interface allows the size of various constructs to be limited 2903** on a connection by connection basis. The first parameter is the 2904** [database connection] whose limit is to be set or queried. The 2905** second parameter is one of the [limit categories] that define a 2906** class of constructs to be size limited. The third parameter is the 2907** new limit for that construct.)^ 2908** 2909** ^If the new limit is a negative number, the limit is unchanged. 2910** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 2911** [limits | hard upper bound] 2912** set at compile-time by a C preprocessor macro called 2913** [limits | SQLITE_MAX_<i>NAME</i>]. 2914** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2915** ^Attempts to increase a limit above its hard upper bound are 2916** silently truncated to the hard upper bound. 2917** 2918** ^Regardless of whether or not the limit was changed, the 2919** [sqlite3_limit()] interface returns the prior value of the limit. 2920** ^Hence, to find the current value of a limit without changing it, 2921** simply invoke this interface with the third parameter set to -1. 2922** 2923** Run-time limits are intended for use in applications that manage 2924** both their own internal database and also databases that are controlled 2925** by untrusted external sources. An example application might be a 2926** web browser that has its own databases for storing history and 2927** separate databases controlled by JavaScript applications downloaded 2928** off the Internet. The internal databases can be given the 2929** large, default limits. Databases managed by external sources can 2930** be given much smaller limits designed to prevent a denial of service 2931** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2932** interface to further control untrusted SQL. The size of the database 2933** created by an untrusted script can be contained using the 2934** [max_page_count] [PRAGMA]. 2935** 2936** New run-time limit categories may be added in future releases. 2937*/ 2938int sqlite3_limit(sqlite3*, int id, int newVal); 2939 2940/* 2941** CAPI3REF: Run-Time Limit Categories 2942** KEYWORDS: {limit category} {*limit categories} 2943** 2944** These constants define various performance limits 2945** that can be lowered at run-time using [sqlite3_limit()]. 2946** The synopsis of the meanings of the various limits is shown below. 2947** Additional information is available at [limits | Limits in SQLite]. 2948** 2949** <dl> 2950** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2951** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 2952** 2953** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2954** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2955** 2956** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2957** <dd>The maximum number of columns in a table definition or in the 2958** result set of a [SELECT] or the maximum number of columns in an index 2959** or in an ORDER BY or GROUP BY clause.</dd>)^ 2960** 2961** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2962** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2963** 2964** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2965** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2966** 2967** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2968** <dd>The maximum number of instructions in a virtual machine program 2969** used to implement an SQL statement. This limit is not currently 2970** enforced, though that might be added in some future release of 2971** SQLite.</dd>)^ 2972** 2973** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2974** <dd>The maximum number of arguments on a function.</dd>)^ 2975** 2976** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2977** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2978** 2979** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 2980** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2981** <dd>The maximum length of the pattern argument to the [LIKE] or 2982** [GLOB] operators.</dd>)^ 2983** 2984** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 2985** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2986** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 2987** 2988** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2989** <dd>The maximum depth of recursion for triggers.</dd>)^ 2990** </dl> 2991*/ 2992#define SQLITE_LIMIT_LENGTH 0 2993#define SQLITE_LIMIT_SQL_LENGTH 1 2994#define SQLITE_LIMIT_COLUMN 2 2995#define SQLITE_LIMIT_EXPR_DEPTH 3 2996#define SQLITE_LIMIT_COMPOUND_SELECT 4 2997#define SQLITE_LIMIT_VDBE_OP 5 2998#define SQLITE_LIMIT_FUNCTION_ARG 6 2999#define SQLITE_LIMIT_ATTACHED 7 3000#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3001#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3002#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3003 3004/* 3005** CAPI3REF: Compiling An SQL Statement 3006** KEYWORDS: {SQL statement compiler} 3007** 3008** To execute an SQL query, it must first be compiled into a byte-code 3009** program using one of these routines. 3010** 3011** The first argument, "db", is a [database connection] obtained from a 3012** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3013** [sqlite3_open16()]. The database connection must not have been closed. 3014** 3015** The second argument, "zSql", is the statement to be compiled, encoded 3016** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 3017** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 3018** use UTF-16. 3019** 3020** ^If the nByte argument is less than zero, then zSql is read up to the 3021** first zero terminator. ^If nByte is non-negative, then it is the maximum 3022** number of bytes read from zSql. ^When nByte is non-negative, the 3023** zSql string ends at either the first '\000' or '\u0000' character or 3024** the nByte-th byte, whichever comes first. If the caller knows 3025** that the supplied string is nul-terminated, then there is a small 3026** performance advantage to be gained by passing an nByte parameter that 3027** is equal to the number of bytes in the input string <i>including</i> 3028** the nul-terminator bytes as this saves SQLite from having to 3029** make a copy of the input string. 3030** 3031** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3032** past the end of the first SQL statement in zSql. These routines only 3033** compile the first statement in zSql, so *pzTail is left pointing to 3034** what remains uncompiled. 3035** 3036** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3037** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3038** to NULL. ^If the input text contains no SQL (if the input is an empty 3039** string or a comment) then *ppStmt is set to NULL. 3040** The calling procedure is responsible for deleting the compiled 3041** SQL statement using [sqlite3_finalize()] after it has finished with it. 3042** ppStmt may not be NULL. 3043** 3044** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3045** otherwise an [error code] is returned. 3046** 3047** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 3048** recommended for all new programs. The two older interfaces are retained 3049** for backwards compatibility, but their use is discouraged. 3050** ^In the "v2" interfaces, the prepared statement 3051** that is returned (the [sqlite3_stmt] object) contains a copy of the 3052** original SQL text. This causes the [sqlite3_step()] interface to 3053** behave differently in three ways: 3054** 3055** <ol> 3056** <li> 3057** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3058** always used to do, [sqlite3_step()] will automatically recompile the SQL 3059** statement and try to run it again. 3060** </li> 3061** 3062** <li> 3063** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3064** [error codes] or [extended error codes]. ^The legacy behavior was that 3065** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3066** and the application would have to make a second call to [sqlite3_reset()] 3067** in order to find the underlying cause of the problem. With the "v2" prepare 3068** interfaces, the underlying reason for the error is returned immediately. 3069** </li> 3070** 3071** <li> 3072** ^If the specific value bound to [parameter | host parameter] in the 3073** WHERE clause might influence the choice of query plan for a statement, 3074** then the statement will be automatically recompiled, as if there had been 3075** a schema change, on the first [sqlite3_step()] call following any change 3076** to the [sqlite3_bind_text | bindings] of that [parameter]. 3077** ^The specific value of WHERE-clause [parameter] might influence the 3078** choice of query plan if the parameter is the left-hand side of a [LIKE] 3079** or [GLOB] operator or if the parameter is compared to an indexed column 3080** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3081** the 3082** </li> 3083** </ol> 3084*/ 3085int sqlite3_prepare( 3086 sqlite3 *db, /* Database handle */ 3087 const char *zSql, /* SQL statement, UTF-8 encoded */ 3088 int nByte, /* Maximum length of zSql in bytes. */ 3089 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3090 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3091); 3092int sqlite3_prepare_v2( 3093 sqlite3 *db, /* Database handle */ 3094 const char *zSql, /* SQL statement, UTF-8 encoded */ 3095 int nByte, /* Maximum length of zSql in bytes. */ 3096 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3097 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3098); 3099int sqlite3_prepare16( 3100 sqlite3 *db, /* Database handle */ 3101 const void *zSql, /* SQL statement, UTF-16 encoded */ 3102 int nByte, /* Maximum length of zSql in bytes. */ 3103 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3104 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3105); 3106int sqlite3_prepare16_v2( 3107 sqlite3 *db, /* Database handle */ 3108 const void *zSql, /* SQL statement, UTF-16 encoded */ 3109 int nByte, /* Maximum length of zSql in bytes. */ 3110 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3111 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3112); 3113 3114/* 3115** CAPI3REF: Retrieving Statement SQL 3116** 3117** ^This interface can be used to retrieve a saved copy of the original 3118** SQL text used to create a [prepared statement] if that statement was 3119** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 3120*/ 3121const char *sqlite3_sql(sqlite3_stmt *pStmt); 3122 3123/* 3124** CAPI3REF: Determine If An SQL Statement Writes The Database 3125** 3126** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3127** and only if the [prepared statement] X makes no direct changes to 3128** the content of the database file. 3129** 3130** Note that [application-defined SQL functions] or 3131** [virtual tables] might change the database indirectly as a side effect. 3132** ^(For example, if an application defines a function "eval()" that 3133** calls [sqlite3_exec()], then the following SQL statement would 3134** change the database file through side-effects: 3135** 3136** <blockquote><pre> 3137** SELECT eval('DELETE FROM t1') FROM t2; 3138** </pre></blockquote> 3139** 3140** But because the [SELECT] statement does not change the database file 3141** directly, sqlite3_stmt_readonly() would still return true.)^ 3142** 3143** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3144** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3145** since the statements themselves do not actually modify the database but 3146** rather they control the timing of when other statements modify the 3147** database. ^The [ATTACH] and [DETACH] statements also cause 3148** sqlite3_stmt_readonly() to return true since, while those statements 3149** change the configuration of a database connection, they do not make 3150** changes to the content of the database files on disk. 3151*/ 3152int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3153 3154/* 3155** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3156** 3157** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3158** [prepared statement] S has been stepped at least once using 3159** [sqlite3_step(S)] but has not run to completion and/or has not 3160** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3161** interface returns false if S is a NULL pointer. If S is not a 3162** NULL pointer and is not a pointer to a valid [prepared statement] 3163** object, then the behavior is undefined and probably undesirable. 3164** 3165** This interface can be used in combination [sqlite3_next_stmt()] 3166** to locate all prepared statements associated with a database 3167** connection that are in need of being reset. This can be used, 3168** for example, in diagnostic routines to search for prepared 3169** statements that are holding a transaction open. 3170*/ 3171int sqlite3_stmt_busy(sqlite3_stmt*); 3172 3173/* 3174** CAPI3REF: Dynamically Typed Value Object 3175** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3176** 3177** SQLite uses the sqlite3_value object to represent all values 3178** that can be stored in a database table. SQLite uses dynamic typing 3179** for the values it stores. ^Values stored in sqlite3_value objects 3180** can be integers, floating point values, strings, BLOBs, or NULL. 3181** 3182** An sqlite3_value object may be either "protected" or "unprotected". 3183** Some interfaces require a protected sqlite3_value. Other interfaces 3184** will accept either a protected or an unprotected sqlite3_value. 3185** Every interface that accepts sqlite3_value arguments specifies 3186** whether or not it requires a protected sqlite3_value. 3187** 3188** The terms "protected" and "unprotected" refer to whether or not 3189** a mutex is held. An internal mutex is held for a protected 3190** sqlite3_value object but no mutex is held for an unprotected 3191** sqlite3_value object. If SQLite is compiled to be single-threaded 3192** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3193** or if SQLite is run in one of reduced mutex modes 3194** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3195** then there is no distinction between protected and unprotected 3196** sqlite3_value objects and they can be used interchangeably. However, 3197** for maximum code portability it is recommended that applications 3198** still make the distinction between protected and unprotected 3199** sqlite3_value objects even when not strictly required. 3200** 3201** ^The sqlite3_value objects that are passed as parameters into the 3202** implementation of [application-defined SQL functions] are protected. 3203** ^The sqlite3_value object returned by 3204** [sqlite3_column_value()] is unprotected. 3205** Unprotected sqlite3_value objects may only be used with 3206** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3207** The [sqlite3_value_blob | sqlite3_value_type()] family of 3208** interfaces require protected sqlite3_value objects. 3209*/ 3210typedef struct Mem sqlite3_value; 3211 3212/* 3213** CAPI3REF: SQL Function Context Object 3214** 3215** The context in which an SQL function executes is stored in an 3216** sqlite3_context object. ^A pointer to an sqlite3_context object 3217** is always first parameter to [application-defined SQL functions]. 3218** The application-defined SQL function implementation will pass this 3219** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3220** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3221** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3222** and/or [sqlite3_set_auxdata()]. 3223*/ 3224typedef struct sqlite3_context sqlite3_context; 3225 3226/* 3227** CAPI3REF: Binding Values To Prepared Statements 3228** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3229** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3230** 3231** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3232** literals may be replaced by a [parameter] that matches one of following 3233** templates: 3234** 3235** <ul> 3236** <li> ? 3237** <li> ?NNN 3238** <li> :VVV 3239** <li> @VVV 3240** <li> $VVV 3241** </ul> 3242** 3243** In the templates above, NNN represents an integer literal, 3244** and VVV represents an alphanumeric identifier.)^ ^The values of these 3245** parameters (also called "host parameter names" or "SQL parameters") 3246** can be set using the sqlite3_bind_*() routines defined here. 3247** 3248** ^The first argument to the sqlite3_bind_*() routines is always 3249** a pointer to the [sqlite3_stmt] object returned from 3250** [sqlite3_prepare_v2()] or its variants. 3251** 3252** ^The second argument is the index of the SQL parameter to be set. 3253** ^The leftmost SQL parameter has an index of 1. ^When the same named 3254** SQL parameter is used more than once, second and subsequent 3255** occurrences have the same index as the first occurrence. 3256** ^The index for named parameters can be looked up using the 3257** [sqlite3_bind_parameter_index()] API if desired. ^The index 3258** for "?NNN" parameters is the value of NNN. 3259** ^The NNN value must be between 1 and the [sqlite3_limit()] 3260** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3261** 3262** ^The third argument is the value to bind to the parameter. 3263** 3264** ^(In those routines that have a fourth argument, its value is the 3265** number of bytes in the parameter. To be clear: the value is the 3266** number of <u>bytes</u> in the value, not the number of characters.)^ 3267** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3268** is negative, then the length of the string is 3269** the number of bytes up to the first zero terminator. 3270** If the fourth parameter to sqlite3_bind_blob() is negative, then 3271** the behavior is undefined. 3272** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3273** or sqlite3_bind_text16() then that parameter must be the byte offset 3274** where the NUL terminator would occur assuming the string were NUL 3275** terminated. If any NUL characters occur at byte offsets less than 3276** the value of the fourth parameter then the resulting string value will 3277** contain embedded NULs. The result of expressions involving strings 3278** with embedded NULs is undefined. 3279** 3280** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 3281** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 3282** string after SQLite has finished with it. ^The destructor is called 3283** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(), 3284** sqlite3_bind_text(), or sqlite3_bind_text16() fails. 3285** ^If the fifth argument is 3286** the special value [SQLITE_STATIC], then SQLite assumes that the 3287** information is in static, unmanaged space and does not need to be freed. 3288** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3289** SQLite makes its own private copy of the data immediately, before 3290** the sqlite3_bind_*() routine returns. 3291** 3292** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3293** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3294** (just an integer to hold its size) while it is being processed. 3295** Zeroblobs are intended to serve as placeholders for BLOBs whose 3296** content is later written using 3297** [sqlite3_blob_open | incremental BLOB I/O] routines. 3298** ^A negative value for the zeroblob results in a zero-length BLOB. 3299** 3300** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3301** for the [prepared statement] or with a prepared statement for which 3302** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3303** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3304** routine is passed a [prepared statement] that has been finalized, the 3305** result is undefined and probably harmful. 3306** 3307** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3308** ^Unbound parameters are interpreted as NULL. 3309** 3310** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3311** [error code] if anything goes wrong. 3312** ^[SQLITE_RANGE] is returned if the parameter 3313** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3314** 3315** See also: [sqlite3_bind_parameter_count()], 3316** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3317*/ 3318int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3319int sqlite3_bind_double(sqlite3_stmt*, int, double); 3320int sqlite3_bind_int(sqlite3_stmt*, int, int); 3321int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3322int sqlite3_bind_null(sqlite3_stmt*, int); 3323int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 3324int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3325int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3326int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3327 3328/* 3329** CAPI3REF: Number Of SQL Parameters 3330** 3331** ^This routine can be used to find the number of [SQL parameters] 3332** in a [prepared statement]. SQL parameters are tokens of the 3333** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3334** placeholders for values that are [sqlite3_bind_blob | bound] 3335** to the parameters at a later time. 3336** 3337** ^(This routine actually returns the index of the largest (rightmost) 3338** parameter. For all forms except ?NNN, this will correspond to the 3339** number of unique parameters. If parameters of the ?NNN form are used, 3340** there may be gaps in the list.)^ 3341** 3342** See also: [sqlite3_bind_blob|sqlite3_bind()], 3343** [sqlite3_bind_parameter_name()], and 3344** [sqlite3_bind_parameter_index()]. 3345*/ 3346int sqlite3_bind_parameter_count(sqlite3_stmt*); 3347 3348/* 3349** CAPI3REF: Name Of A Host Parameter 3350** 3351** ^The sqlite3_bind_parameter_name(P,N) interface returns 3352** the name of the N-th [SQL parameter] in the [prepared statement] P. 3353** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3354** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3355** respectively. 3356** In other words, the initial ":" or "$" or "@" or "?" 3357** is included as part of the name.)^ 3358** ^Parameters of the form "?" without a following integer have no name 3359** and are referred to as "nameless" or "anonymous parameters". 3360** 3361** ^The first host parameter has an index of 1, not 0. 3362** 3363** ^If the value N is out of range or if the N-th parameter is 3364** nameless, then NULL is returned. ^The returned string is 3365** always in UTF-8 encoding even if the named parameter was 3366** originally specified as UTF-16 in [sqlite3_prepare16()] or 3367** [sqlite3_prepare16_v2()]. 3368** 3369** See also: [sqlite3_bind_blob|sqlite3_bind()], 3370** [sqlite3_bind_parameter_count()], and 3371** [sqlite3_bind_parameter_index()]. 3372*/ 3373const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3374 3375/* 3376** CAPI3REF: Index Of A Parameter With A Given Name 3377** 3378** ^Return the index of an SQL parameter given its name. ^The 3379** index value returned is suitable for use as the second 3380** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3381** is returned if no matching parameter is found. ^The parameter 3382** name must be given in UTF-8 even if the original statement 3383** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3384** 3385** See also: [sqlite3_bind_blob|sqlite3_bind()], 3386** [sqlite3_bind_parameter_count()], and 3387** [sqlite3_bind_parameter_index()]. 3388*/ 3389int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3390 3391/* 3392** CAPI3REF: Reset All Bindings On A Prepared Statement 3393** 3394** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3395** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3396** ^Use this routine to reset all host parameters to NULL. 3397*/ 3398int sqlite3_clear_bindings(sqlite3_stmt*); 3399 3400/* 3401** CAPI3REF: Number Of Columns In A Result Set 3402** 3403** ^Return the number of columns in the result set returned by the 3404** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3405** statement that does not return data (for example an [UPDATE]). 3406** 3407** See also: [sqlite3_data_count()] 3408*/ 3409int sqlite3_column_count(sqlite3_stmt *pStmt); 3410 3411/* 3412** CAPI3REF: Column Names In A Result Set 3413** 3414** ^These routines return the name assigned to a particular column 3415** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3416** interface returns a pointer to a zero-terminated UTF-8 string 3417** and sqlite3_column_name16() returns a pointer to a zero-terminated 3418** UTF-16 string. ^The first parameter is the [prepared statement] 3419** that implements the [SELECT] statement. ^The second parameter is the 3420** column number. ^The leftmost column is number 0. 3421** 3422** ^The returned string pointer is valid until either the [prepared statement] 3423** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3424** reprepared by the first call to [sqlite3_step()] for a particular run 3425** or until the next call to 3426** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3427** 3428** ^If sqlite3_malloc() fails during the processing of either routine 3429** (for example during a conversion from UTF-8 to UTF-16) then a 3430** NULL pointer is returned. 3431** 3432** ^The name of a result column is the value of the "AS" clause for 3433** that column, if there is an AS clause. If there is no AS clause 3434** then the name of the column is unspecified and may change from 3435** one release of SQLite to the next. 3436*/ 3437const char *sqlite3_column_name(sqlite3_stmt*, int N); 3438const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3439 3440/* 3441** CAPI3REF: Source Of Data In A Query Result 3442** 3443** ^These routines provide a means to determine the database, table, and 3444** table column that is the origin of a particular result column in 3445** [SELECT] statement. 3446** ^The name of the database or table or column can be returned as 3447** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3448** the database name, the _table_ routines return the table name, and 3449** the origin_ routines return the column name. 3450** ^The returned string is valid until the [prepared statement] is destroyed 3451** using [sqlite3_finalize()] or until the statement is automatically 3452** reprepared by the first call to [sqlite3_step()] for a particular run 3453** or until the same information is requested 3454** again in a different encoding. 3455** 3456** ^The names returned are the original un-aliased names of the 3457** database, table, and column. 3458** 3459** ^The first argument to these interfaces is a [prepared statement]. 3460** ^These functions return information about the Nth result column returned by 3461** the statement, where N is the second function argument. 3462** ^The left-most column is column 0 for these routines. 3463** 3464** ^If the Nth column returned by the statement is an expression or 3465** subquery and is not a column value, then all of these functions return 3466** NULL. ^These routine might also return NULL if a memory allocation error 3467** occurs. ^Otherwise, they return the name of the attached database, table, 3468** or column that query result column was extracted from. 3469** 3470** ^As with all other SQLite APIs, those whose names end with "16" return 3471** UTF-16 encoded strings and the other functions return UTF-8. 3472** 3473** ^These APIs are only available if the library was compiled with the 3474** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3475** 3476** If two or more threads call one or more of these routines against the same 3477** prepared statement and column at the same time then the results are 3478** undefined. 3479** 3480** If two or more threads call one or more 3481** [sqlite3_column_database_name | column metadata interfaces] 3482** for the same [prepared statement] and result column 3483** at the same time then the results are undefined. 3484*/ 3485const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3486const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3487const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3488const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3489const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3490const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3491 3492/* 3493** CAPI3REF: Declared Datatype Of A Query Result 3494** 3495** ^(The first parameter is a [prepared statement]. 3496** If this statement is a [SELECT] statement and the Nth column of the 3497** returned result set of that [SELECT] is a table column (not an 3498** expression or subquery) then the declared type of the table 3499** column is returned.)^ ^If the Nth column of the result set is an 3500** expression or subquery, then a NULL pointer is returned. 3501** ^The returned string is always UTF-8 encoded. 3502** 3503** ^(For example, given the database schema: 3504** 3505** CREATE TABLE t1(c1 VARIANT); 3506** 3507** and the following statement to be compiled: 3508** 3509** SELECT c1 + 1, c1 FROM t1; 3510** 3511** this routine would return the string "VARIANT" for the second result 3512** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3513** 3514** ^SQLite uses dynamic run-time typing. ^So just because a column 3515** is declared to contain a particular type does not mean that the 3516** data stored in that column is of the declared type. SQLite is 3517** strongly typed, but the typing is dynamic not static. ^Type 3518** is associated with individual values, not with the containers 3519** used to hold those values. 3520*/ 3521const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3522const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3523 3524/* 3525** CAPI3REF: Evaluate An SQL Statement 3526** 3527** After a [prepared statement] has been prepared using either 3528** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3529** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3530** must be called one or more times to evaluate the statement. 3531** 3532** The details of the behavior of the sqlite3_step() interface depend 3533** on whether the statement was prepared using the newer "v2" interface 3534** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3535** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3536** new "v2" interface is recommended for new applications but the legacy 3537** interface will continue to be supported. 3538** 3539** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3540** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3541** ^With the "v2" interface, any of the other [result codes] or 3542** [extended result codes] might be returned as well. 3543** 3544** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3545** database locks it needs to do its job. ^If the statement is a [COMMIT] 3546** or occurs outside of an explicit transaction, then you can retry the 3547** statement. If the statement is not a [COMMIT] and occurs within an 3548** explicit transaction then you should rollback the transaction before 3549** continuing. 3550** 3551** ^[SQLITE_DONE] means that the statement has finished executing 3552** successfully. sqlite3_step() should not be called again on this virtual 3553** machine without first calling [sqlite3_reset()] to reset the virtual 3554** machine back to its initial state. 3555** 3556** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3557** is returned each time a new row of data is ready for processing by the 3558** caller. The values may be accessed using the [column access functions]. 3559** sqlite3_step() is called again to retrieve the next row of data. 3560** 3561** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3562** violation) has occurred. sqlite3_step() should not be called again on 3563** the VM. More information may be found by calling [sqlite3_errmsg()]. 3564** ^With the legacy interface, a more specific error code (for example, 3565** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3566** can be obtained by calling [sqlite3_reset()] on the 3567** [prepared statement]. ^In the "v2" interface, 3568** the more specific error code is returned directly by sqlite3_step(). 3569** 3570** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3571** Perhaps it was called on a [prepared statement] that has 3572** already been [sqlite3_finalize | finalized] or on one that had 3573** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3574** be the case that the same database connection is being used by two or 3575** more threads at the same moment in time. 3576** 3577** For all versions of SQLite up to and including 3.6.23.1, a call to 3578** [sqlite3_reset()] was required after sqlite3_step() returned anything 3579** other than [SQLITE_ROW] before any subsequent invocation of 3580** sqlite3_step(). Failure to reset the prepared statement using 3581** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3582** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3583** calling [sqlite3_reset()] automatically in this circumstance rather 3584** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3585** break because any application that ever receives an SQLITE_MISUSE error 3586** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3587** can be used to restore the legacy behavior. 3588** 3589** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3590** API always returns a generic error code, [SQLITE_ERROR], following any 3591** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3592** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3593** specific [error codes] that better describes the error. 3594** We admit that this is a goofy design. The problem has been fixed 3595** with the "v2" interface. If you prepare all of your SQL statements 3596** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3597** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3598** then the more specific [error codes] are returned directly 3599** by sqlite3_step(). The use of the "v2" interface is recommended. 3600*/ 3601int sqlite3_step(sqlite3_stmt*); 3602 3603/* 3604** CAPI3REF: Number of columns in a result set 3605** 3606** ^The sqlite3_data_count(P) interface returns the number of columns in the 3607** current row of the result set of [prepared statement] P. 3608** ^If prepared statement P does not have results ready to return 3609** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3610** interfaces) then sqlite3_data_count(P) returns 0. 3611** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3612** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 3613** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 3614** will return non-zero if previous call to [sqlite3_step](P) returned 3615** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 3616** where it always returns zero since each step of that multi-step 3617** pragma returns 0 columns of data. 3618** 3619** See also: [sqlite3_column_count()] 3620*/ 3621int sqlite3_data_count(sqlite3_stmt *pStmt); 3622 3623/* 3624** CAPI3REF: Fundamental Datatypes 3625** KEYWORDS: SQLITE_TEXT 3626** 3627** ^(Every value in SQLite has one of five fundamental datatypes: 3628** 3629** <ul> 3630** <li> 64-bit signed integer 3631** <li> 64-bit IEEE floating point number 3632** <li> string 3633** <li> BLOB 3634** <li> NULL 3635** </ul>)^ 3636** 3637** These constants are codes for each of those types. 3638** 3639** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3640** for a completely different meaning. Software that links against both 3641** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3642** SQLITE_TEXT. 3643*/ 3644#define SQLITE_INTEGER 1 3645#define SQLITE_FLOAT 2 3646#define SQLITE_BLOB 4 3647#define SQLITE_NULL 5 3648#ifdef SQLITE_TEXT 3649# undef SQLITE_TEXT 3650#else 3651# define SQLITE_TEXT 3 3652#endif 3653#define SQLITE3_TEXT 3 3654 3655/* 3656** CAPI3REF: Result Values From A Query 3657** KEYWORDS: {column access functions} 3658** 3659** These routines form the "result set" interface. 3660** 3661** ^These routines return information about a single column of the current 3662** result row of a query. ^In every case the first argument is a pointer 3663** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3664** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3665** and the second argument is the index of the column for which information 3666** should be returned. ^The leftmost column of the result set has the index 0. 3667** ^The number of columns in the result can be determined using 3668** [sqlite3_column_count()]. 3669** 3670** If the SQL statement does not currently point to a valid row, or if the 3671** column index is out of range, the result is undefined. 3672** These routines may only be called when the most recent call to 3673** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3674** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3675** If any of these routines are called after [sqlite3_reset()] or 3676** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3677** something other than [SQLITE_ROW], the results are undefined. 3678** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3679** are called from a different thread while any of these routines 3680** are pending, then the results are undefined. 3681** 3682** ^The sqlite3_column_type() routine returns the 3683** [SQLITE_INTEGER | datatype code] for the initial data type 3684** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3685** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3686** returned by sqlite3_column_type() is only meaningful if no type 3687** conversions have occurred as described below. After a type conversion, 3688** the value returned by sqlite3_column_type() is undefined. Future 3689** versions of SQLite may change the behavior of sqlite3_column_type() 3690** following a type conversion. 3691** 3692** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3693** routine returns the number of bytes in that BLOB or string. 3694** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3695** the string to UTF-8 and then returns the number of bytes. 3696** ^If the result is a numeric value then sqlite3_column_bytes() uses 3697** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3698** the number of bytes in that string. 3699** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3700** 3701** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3702** routine returns the number of bytes in that BLOB or string. 3703** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3704** the string to UTF-16 and then returns the number of bytes. 3705** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3706** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3707** the number of bytes in that string. 3708** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3709** 3710** ^The values returned by [sqlite3_column_bytes()] and 3711** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3712** of the string. ^For clarity: the values returned by 3713** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3714** bytes in the string, not the number of characters. 3715** 3716** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3717** even empty strings, are always zero-terminated. ^The return 3718** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3719** 3720** ^The object returned by [sqlite3_column_value()] is an 3721** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3722** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3723** If the [unprotected sqlite3_value] object returned by 3724** [sqlite3_column_value()] is used in any other way, including calls 3725** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3726** or [sqlite3_value_bytes()], then the behavior is undefined. 3727** 3728** These routines attempt to convert the value where appropriate. ^For 3729** example, if the internal representation is FLOAT and a text result 3730** is requested, [sqlite3_snprintf()] is used internally to perform the 3731** conversion automatically. ^(The following table details the conversions 3732** that are applied: 3733** 3734** <blockquote> 3735** <table border="1"> 3736** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3737** 3738** <tr><td> NULL <td> INTEGER <td> Result is 0 3739** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3740** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3741** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3742** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3743** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3744** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3745** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3746** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3747** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3748** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3749** <tr><td> TEXT <td> FLOAT <td> Use atof() 3750** <tr><td> TEXT <td> BLOB <td> No change 3751** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3752** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3753** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3754** </table> 3755** </blockquote>)^ 3756** 3757** The table above makes reference to standard C library functions atoi() 3758** and atof(). SQLite does not really use these functions. It has its 3759** own equivalent internal routines. The atoi() and atof() names are 3760** used in the table for brevity and because they are familiar to most 3761** C programmers. 3762** 3763** Note that when type conversions occur, pointers returned by prior 3764** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3765** sqlite3_column_text16() may be invalidated. 3766** Type conversions and pointer invalidations might occur 3767** in the following cases: 3768** 3769** <ul> 3770** <li> The initial content is a BLOB and sqlite3_column_text() or 3771** sqlite3_column_text16() is called. A zero-terminator might 3772** need to be added to the string.</li> 3773** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3774** sqlite3_column_text16() is called. The content must be converted 3775** to UTF-16.</li> 3776** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3777** sqlite3_column_text() is called. The content must be converted 3778** to UTF-8.</li> 3779** </ul> 3780** 3781** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3782** not invalidate a prior pointer, though of course the content of the buffer 3783** that the prior pointer references will have been modified. Other kinds 3784** of conversion are done in place when it is possible, but sometimes they 3785** are not possible and in those cases prior pointers are invalidated. 3786** 3787** The safest and easiest to remember policy is to invoke these routines 3788** in one of the following ways: 3789** 3790** <ul> 3791** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3792** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3793** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3794** </ul> 3795** 3796** In other words, you should call sqlite3_column_text(), 3797** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3798** into the desired format, then invoke sqlite3_column_bytes() or 3799** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3800** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3801** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3802** with calls to sqlite3_column_bytes(). 3803** 3804** ^The pointers returned are valid until a type conversion occurs as 3805** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3806** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3807** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3808** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3809** [sqlite3_free()]. 3810** 3811** ^(If a memory allocation error occurs during the evaluation of any 3812** of these routines, a default value is returned. The default value 3813** is either the integer 0, the floating point number 0.0, or a NULL 3814** pointer. Subsequent calls to [sqlite3_errcode()] will return 3815** [SQLITE_NOMEM].)^ 3816*/ 3817const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3818int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3819int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3820double sqlite3_column_double(sqlite3_stmt*, int iCol); 3821int sqlite3_column_int(sqlite3_stmt*, int iCol); 3822sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3823const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3824const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3825int sqlite3_column_type(sqlite3_stmt*, int iCol); 3826sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3827 3828/* 3829** CAPI3REF: Destroy A Prepared Statement Object 3830** 3831** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3832** ^If the most recent evaluation of the statement encountered no errors 3833** or if the statement is never been evaluated, then sqlite3_finalize() returns 3834** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 3835** sqlite3_finalize(S) returns the appropriate [error code] or 3836** [extended error code]. 3837** 3838** ^The sqlite3_finalize(S) routine can be called at any point during 3839** the life cycle of [prepared statement] S: 3840** before statement S is ever evaluated, after 3841** one or more calls to [sqlite3_reset()], or after any call 3842** to [sqlite3_step()] regardless of whether or not the statement has 3843** completed execution. 3844** 3845** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 3846** 3847** The application must finalize every [prepared statement] in order to avoid 3848** resource leaks. It is a grievous error for the application to try to use 3849** a prepared statement after it has been finalized. Any use of a prepared 3850** statement after it has been finalized can result in undefined and 3851** undesirable behavior such as segfaults and heap corruption. 3852*/ 3853int sqlite3_finalize(sqlite3_stmt *pStmt); 3854 3855/* 3856** CAPI3REF: Reset A Prepared Statement Object 3857** 3858** The sqlite3_reset() function is called to reset a [prepared statement] 3859** object back to its initial state, ready to be re-executed. 3860** ^Any SQL statement variables that had values bound to them using 3861** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3862** Use [sqlite3_clear_bindings()] to reset the bindings. 3863** 3864** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3865** back to the beginning of its program. 3866** 3867** ^If the most recent call to [sqlite3_step(S)] for the 3868** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3869** or if [sqlite3_step(S)] has never before been called on S, 3870** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3871** 3872** ^If the most recent call to [sqlite3_step(S)] for the 3873** [prepared statement] S indicated an error, then 3874** [sqlite3_reset(S)] returns an appropriate [error code]. 3875** 3876** ^The [sqlite3_reset(S)] interface does not change the values 3877** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3878*/ 3879int sqlite3_reset(sqlite3_stmt *pStmt); 3880 3881/* 3882** CAPI3REF: Create Or Redefine SQL Functions 3883** KEYWORDS: {function creation routines} 3884** KEYWORDS: {application-defined SQL function} 3885** KEYWORDS: {application-defined SQL functions} 3886** 3887** ^These functions (collectively known as "function creation routines") 3888** are used to add SQL functions or aggregates or to redefine the behavior 3889** of existing SQL functions or aggregates. The only differences between 3890** these routines are the text encoding expected for 3891** the second parameter (the name of the function being created) 3892** and the presence or absence of a destructor callback for 3893** the application data pointer. 3894** 3895** ^The first parameter is the [database connection] to which the SQL 3896** function is to be added. ^If an application uses more than one database 3897** connection then application-defined SQL functions must be added 3898** to each database connection separately. 3899** 3900** ^The second parameter is the name of the SQL function to be created or 3901** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 3902** representation, exclusive of the zero-terminator. ^Note that the name 3903** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 3904** ^Any attempt to create a function with a longer name 3905** will result in [SQLITE_MISUSE] being returned. 3906** 3907** ^The third parameter (nArg) 3908** is the number of arguments that the SQL function or 3909** aggregate takes. ^If this parameter is -1, then the SQL function or 3910** aggregate may take any number of arguments between 0 and the limit 3911** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3912** parameter is less than -1 or greater than 127 then the behavior is 3913** undefined. 3914** 3915** ^The fourth parameter, eTextRep, specifies what 3916** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3917** its parameters. Every SQL function implementation must be able to work 3918** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3919** more efficient with one encoding than another. ^An application may 3920** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3921** times with the same function but with different values of eTextRep. 3922** ^When multiple implementations of the same function are available, SQLite 3923** will pick the one that involves the least amount of data conversion. 3924** If there is only a single implementation which does not care what text 3925** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3926** 3927** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3928** function can gain access to this pointer using [sqlite3_user_data()].)^ 3929** 3930** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 3931** pointers to C-language functions that implement the SQL function or 3932** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3933** callback only; NULL pointers must be passed as the xStep and xFinal 3934** parameters. ^An aggregate SQL function requires an implementation of xStep 3935** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 3936** SQL function or aggregate, pass NULL pointers for all three function 3937** callbacks. 3938** 3939** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 3940** then it is destructor for the application data pointer. 3941** The destructor is invoked when the function is deleted, either by being 3942** overloaded or when the database connection closes.)^ 3943** ^The destructor is also invoked if the call to 3944** sqlite3_create_function_v2() fails. 3945** ^When the destructor callback of the tenth parameter is invoked, it 3946** is passed a single argument which is a copy of the application data 3947** pointer which was the fifth parameter to sqlite3_create_function_v2(). 3948** 3949** ^It is permitted to register multiple implementations of the same 3950** functions with the same name but with either differing numbers of 3951** arguments or differing preferred text encodings. ^SQLite will use 3952** the implementation that most closely matches the way in which the 3953** SQL function is used. ^A function implementation with a non-negative 3954** nArg parameter is a better match than a function implementation with 3955** a negative nArg. ^A function where the preferred text encoding 3956** matches the database encoding is a better 3957** match than a function where the encoding is different. 3958** ^A function where the encoding difference is between UTF16le and UTF16be 3959** is a closer match than a function where the encoding difference is 3960** between UTF8 and UTF16. 3961** 3962** ^Built-in functions may be overloaded by new application-defined functions. 3963** 3964** ^An application-defined function is permitted to call other 3965** SQLite interfaces. However, such calls must not 3966** close the database connection nor finalize or reset the prepared 3967** statement in which the function is running. 3968*/ 3969int sqlite3_create_function( 3970 sqlite3 *db, 3971 const char *zFunctionName, 3972 int nArg, 3973 int eTextRep, 3974 void *pApp, 3975 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3976 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3977 void (*xFinal)(sqlite3_context*) 3978); 3979int sqlite3_create_function16( 3980 sqlite3 *db, 3981 const void *zFunctionName, 3982 int nArg, 3983 int eTextRep, 3984 void *pApp, 3985 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3986 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3987 void (*xFinal)(sqlite3_context*) 3988); 3989int sqlite3_create_function_v2( 3990 sqlite3 *db, 3991 const char *zFunctionName, 3992 int nArg, 3993 int eTextRep, 3994 void *pApp, 3995 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3996 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3997 void (*xFinal)(sqlite3_context*), 3998 void(*xDestroy)(void*) 3999); 4000 4001/* 4002** CAPI3REF: Text Encodings 4003** 4004** These constant define integer codes that represent the various 4005** text encodings supported by SQLite. 4006*/ 4007#define SQLITE_UTF8 1 4008#define SQLITE_UTF16LE 2 4009#define SQLITE_UTF16BE 3 4010#define SQLITE_UTF16 4 /* Use native byte order */ 4011#define SQLITE_ANY 5 /* sqlite3_create_function only */ 4012#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4013 4014/* 4015** CAPI3REF: Deprecated Functions 4016** DEPRECATED 4017** 4018** These functions are [deprecated]. In order to maintain 4019** backwards compatibility with older code, these functions continue 4020** to be supported. However, new applications should avoid 4021** the use of these functions. To help encourage people to avoid 4022** using these functions, we are not going to tell you what they do. 4023*/ 4024#ifndef SQLITE_OMIT_DEPRECATED 4025SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4026SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4027SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4028SQLITE_DEPRECATED int sqlite3_global_recover(void); 4029SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4030SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4031 void*,sqlite3_int64); 4032#endif 4033 4034/* 4035** CAPI3REF: Obtaining SQL Function Parameter Values 4036** 4037** The C-language implementation of SQL functions and aggregates uses 4038** this set of interface routines to access the parameter values on 4039** the function or aggregate. 4040** 4041** The xFunc (for scalar functions) or xStep (for aggregates) parameters 4042** to [sqlite3_create_function()] and [sqlite3_create_function16()] 4043** define callbacks that implement the SQL functions and aggregates. 4044** The 3rd parameter to these callbacks is an array of pointers to 4045** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 4046** each parameter to the SQL function. These routines are used to 4047** extract values from the [sqlite3_value] objects. 4048** 4049** These routines work only with [protected sqlite3_value] objects. 4050** Any attempt to use these routines on an [unprotected sqlite3_value] 4051** object results in undefined behavior. 4052** 4053** ^These routines work just like the corresponding [column access functions] 4054** except that these routines take a single [protected sqlite3_value] object 4055** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4056** 4057** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4058** in the native byte-order of the host machine. ^The 4059** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4060** extract UTF-16 strings as big-endian and little-endian respectively. 4061** 4062** ^(The sqlite3_value_numeric_type() interface attempts to apply 4063** numeric affinity to the value. This means that an attempt is 4064** made to convert the value to an integer or floating point. If 4065** such a conversion is possible without loss of information (in other 4066** words, if the value is a string that looks like a number) 4067** then the conversion is performed. Otherwise no conversion occurs. 4068** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4069** 4070** Please pay particular attention to the fact that the pointer returned 4071** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4072** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4073** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4074** or [sqlite3_value_text16()]. 4075** 4076** These routines must be called from the same thread as 4077** the SQL function that supplied the [sqlite3_value*] parameters. 4078*/ 4079const void *sqlite3_value_blob(sqlite3_value*); 4080int sqlite3_value_bytes(sqlite3_value*); 4081int sqlite3_value_bytes16(sqlite3_value*); 4082double sqlite3_value_double(sqlite3_value*); 4083int sqlite3_value_int(sqlite3_value*); 4084sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4085const unsigned char *sqlite3_value_text(sqlite3_value*); 4086const void *sqlite3_value_text16(sqlite3_value*); 4087const void *sqlite3_value_text16le(sqlite3_value*); 4088const void *sqlite3_value_text16be(sqlite3_value*); 4089int sqlite3_value_type(sqlite3_value*); 4090int sqlite3_value_numeric_type(sqlite3_value*); 4091 4092/* 4093** CAPI3REF: Obtain Aggregate Function Context 4094** 4095** Implementations of aggregate SQL functions use this 4096** routine to allocate memory for storing their state. 4097** 4098** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4099** for a particular aggregate function, SQLite 4100** allocates N of memory, zeroes out that memory, and returns a pointer 4101** to the new memory. ^On second and subsequent calls to 4102** sqlite3_aggregate_context() for the same aggregate function instance, 4103** the same buffer is returned. Sqlite3_aggregate_context() is normally 4104** called once for each invocation of the xStep callback and then one 4105** last time when the xFinal callback is invoked. ^(When no rows match 4106** an aggregate query, the xStep() callback of the aggregate function 4107** implementation is never called and xFinal() is called exactly once. 4108** In those cases, sqlite3_aggregate_context() might be called for the 4109** first time from within xFinal().)^ 4110** 4111** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4112** when first called if N is less than or equal to zero or if a memory 4113** allocate error occurs. 4114** 4115** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4116** determined by the N parameter on first successful call. Changing the 4117** value of N in subsequent call to sqlite3_aggregate_context() within 4118** the same aggregate function instance will not resize the memory 4119** allocation.)^ Within the xFinal callback, it is customary to set 4120** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4121** pointless memory allocations occur. 4122** 4123** ^SQLite automatically frees the memory allocated by 4124** sqlite3_aggregate_context() when the aggregate query concludes. 4125** 4126** The first parameter must be a copy of the 4127** [sqlite3_context | SQL function context] that is the first parameter 4128** to the xStep or xFinal callback routine that implements the aggregate 4129** function. 4130** 4131** This routine must be called from the same thread in which 4132** the aggregate SQL function is running. 4133*/ 4134void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4135 4136/* 4137** CAPI3REF: User Data For Functions 4138** 4139** ^The sqlite3_user_data() interface returns a copy of 4140** the pointer that was the pUserData parameter (the 5th parameter) 4141** of the [sqlite3_create_function()] 4142** and [sqlite3_create_function16()] routines that originally 4143** registered the application defined function. 4144** 4145** This routine must be called from the same thread in which 4146** the application-defined function is running. 4147*/ 4148void *sqlite3_user_data(sqlite3_context*); 4149 4150/* 4151** CAPI3REF: Database Connection For Functions 4152** 4153** ^The sqlite3_context_db_handle() interface returns a copy of 4154** the pointer to the [database connection] (the 1st parameter) 4155** of the [sqlite3_create_function()] 4156** and [sqlite3_create_function16()] routines that originally 4157** registered the application defined function. 4158*/ 4159sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4160 4161/* 4162** CAPI3REF: Function Auxiliary Data 4163** 4164** The following two functions may be used by scalar SQL functions to 4165** associate metadata with argument values. If the same value is passed to 4166** multiple invocations of the same SQL function during query execution, under 4167** some circumstances the associated metadata may be preserved. This may 4168** be used, for example, to add a regular-expression matching scalar 4169** function. The compiled version of the regular expression is stored as 4170** metadata associated with the SQL value passed as the regular expression 4171** pattern. The compiled regular expression can be reused on multiple 4172** invocations of the same function so that the original pattern string 4173** does not need to be recompiled on each invocation. 4174** 4175** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4176** associated by the sqlite3_set_auxdata() function with the Nth argument 4177** value to the application-defined function. ^If no metadata has been ever 4178** been set for the Nth argument of the function, or if the corresponding 4179** function parameter has changed since the meta-data was set, 4180** then sqlite3_get_auxdata() returns a NULL pointer. 4181** 4182** ^The sqlite3_set_auxdata() interface saves the metadata 4183** pointed to by its 3rd parameter as the metadata for the N-th 4184** argument of the application-defined function. Subsequent 4185** calls to sqlite3_get_auxdata() might return this data, if it has 4186** not been destroyed. 4187** ^If it is not NULL, SQLite will invoke the destructor 4188** function given by the 4th parameter to sqlite3_set_auxdata() on 4189** the metadata when the corresponding function parameter changes 4190** or when the SQL statement completes, whichever comes first. 4191** 4192** SQLite is free to call the destructor and drop metadata on any 4193** parameter of any function at any time. ^The only guarantee is that 4194** the destructor will be called before the metadata is dropped. 4195** 4196** ^(In practice, metadata is preserved between function calls for 4197** expressions that are constant at compile time. This includes literal 4198** values and [parameters].)^ 4199** 4200** These routines must be called from the same thread in which 4201** the SQL function is running. 4202*/ 4203void *sqlite3_get_auxdata(sqlite3_context*, int N); 4204void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4205 4206 4207/* 4208** CAPI3REF: Constants Defining Special Destructor Behavior 4209** 4210** These are special values for the destructor that is passed in as the 4211** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4212** argument is SQLITE_STATIC, it means that the content pointer is constant 4213** and will never change. It does not need to be destroyed. ^The 4214** SQLITE_TRANSIENT value means that the content will likely change in 4215** the near future and that SQLite should make its own private copy of 4216** the content before returning. 4217** 4218** The typedef is necessary to work around problems in certain 4219** C++ compilers. See ticket #2191. 4220*/ 4221typedef void (*sqlite3_destructor_type)(void*); 4222#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4223#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4224 4225/* 4226** CAPI3REF: Setting The Result Of An SQL Function 4227** 4228** These routines are used by the xFunc or xFinal callbacks that 4229** implement SQL functions and aggregates. See 4230** [sqlite3_create_function()] and [sqlite3_create_function16()] 4231** for additional information. 4232** 4233** These functions work very much like the [parameter binding] family of 4234** functions used to bind values to host parameters in prepared statements. 4235** Refer to the [SQL parameter] documentation for additional information. 4236** 4237** ^The sqlite3_result_blob() interface sets the result from 4238** an application-defined function to be the BLOB whose content is pointed 4239** to by the second parameter and which is N bytes long where N is the 4240** third parameter. 4241** 4242** ^The sqlite3_result_zeroblob() interfaces set the result of 4243** the application-defined function to be a BLOB containing all zero 4244** bytes and N bytes in size, where N is the value of the 2nd parameter. 4245** 4246** ^The sqlite3_result_double() interface sets the result from 4247** an application-defined function to be a floating point value specified 4248** by its 2nd argument. 4249** 4250** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4251** cause the implemented SQL function to throw an exception. 4252** ^SQLite uses the string pointed to by the 4253** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4254** as the text of an error message. ^SQLite interprets the error 4255** message string from sqlite3_result_error() as UTF-8. ^SQLite 4256** interprets the string from sqlite3_result_error16() as UTF-16 in native 4257** byte order. ^If the third parameter to sqlite3_result_error() 4258** or sqlite3_result_error16() is negative then SQLite takes as the error 4259** message all text up through the first zero character. 4260** ^If the third parameter to sqlite3_result_error() or 4261** sqlite3_result_error16() is non-negative then SQLite takes that many 4262** bytes (not characters) from the 2nd parameter as the error message. 4263** ^The sqlite3_result_error() and sqlite3_result_error16() 4264** routines make a private copy of the error message text before 4265** they return. Hence, the calling function can deallocate or 4266** modify the text after they return without harm. 4267** ^The sqlite3_result_error_code() function changes the error code 4268** returned by SQLite as a result of an error in a function. ^By default, 4269** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4270** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4271** 4272** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 4273** error indicating that a string or BLOB is too long to represent. 4274** 4275** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 4276** error indicating that a memory allocation failed. 4277** 4278** ^The sqlite3_result_int() interface sets the return value 4279** of the application-defined function to be the 32-bit signed integer 4280** value given in the 2nd argument. 4281** ^The sqlite3_result_int64() interface sets the return value 4282** of the application-defined function to be the 64-bit signed integer 4283** value given in the 2nd argument. 4284** 4285** ^The sqlite3_result_null() interface sets the return value 4286** of the application-defined function to be NULL. 4287** 4288** ^The sqlite3_result_text(), sqlite3_result_text16(), 4289** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4290** set the return value of the application-defined function to be 4291** a text string which is represented as UTF-8, UTF-16 native byte order, 4292** UTF-16 little endian, or UTF-16 big endian, respectively. 4293** ^SQLite takes the text result from the application from 4294** the 2nd parameter of the sqlite3_result_text* interfaces. 4295** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4296** is negative, then SQLite takes result text from the 2nd parameter 4297** through the first zero character. 4298** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4299** is non-negative, then as many bytes (not characters) of the text 4300** pointed to by the 2nd parameter are taken as the application-defined 4301** function result. If the 3rd parameter is non-negative, then it 4302** must be the byte offset into the string where the NUL terminator would 4303** appear if the string where NUL terminated. If any NUL characters occur 4304** in the string at a byte offset that is less than the value of the 3rd 4305** parameter, then the resulting string will contain embedded NULs and the 4306** result of expressions operating on strings with embedded NULs is undefined. 4307** ^If the 4th parameter to the sqlite3_result_text* interfaces 4308** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4309** function as the destructor on the text or BLOB result when it has 4310** finished using that result. 4311** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4312** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4313** assumes that the text or BLOB result is in constant space and does not 4314** copy the content of the parameter nor call a destructor on the content 4315** when it has finished using that result. 4316** ^If the 4th parameter to the sqlite3_result_text* interfaces 4317** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4318** then SQLite makes a copy of the result into space obtained from 4319** from [sqlite3_malloc()] before it returns. 4320** 4321** ^The sqlite3_result_value() interface sets the result of 4322** the application-defined function to be a copy the 4323** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4324** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4325** so that the [sqlite3_value] specified in the parameter may change or 4326** be deallocated after sqlite3_result_value() returns without harm. 4327** ^A [protected sqlite3_value] object may always be used where an 4328** [unprotected sqlite3_value] object is required, so either 4329** kind of [sqlite3_value] object can be used with this interface. 4330** 4331** If these routines are called from within the different thread 4332** than the one containing the application-defined function that received 4333** the [sqlite3_context] pointer, the results are undefined. 4334*/ 4335void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4336void sqlite3_result_double(sqlite3_context*, double); 4337void sqlite3_result_error(sqlite3_context*, const char*, int); 4338void sqlite3_result_error16(sqlite3_context*, const void*, int); 4339void sqlite3_result_error_toobig(sqlite3_context*); 4340void sqlite3_result_error_nomem(sqlite3_context*); 4341void sqlite3_result_error_code(sqlite3_context*, int); 4342void sqlite3_result_int(sqlite3_context*, int); 4343void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4344void sqlite3_result_null(sqlite3_context*); 4345void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4346void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4347void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4348void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4349void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4350void sqlite3_result_zeroblob(sqlite3_context*, int n); 4351 4352/* 4353** CAPI3REF: Define New Collating Sequences 4354** 4355** ^These functions add, remove, or modify a [collation] associated 4356** with the [database connection] specified as the first argument. 4357** 4358** ^The name of the collation is a UTF-8 string 4359** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4360** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4361** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4362** considered to be the same name. 4363** 4364** ^(The third argument (eTextRep) must be one of the constants: 4365** <ul> 4366** <li> [SQLITE_UTF8], 4367** <li> [SQLITE_UTF16LE], 4368** <li> [SQLITE_UTF16BE], 4369** <li> [SQLITE_UTF16], or 4370** <li> [SQLITE_UTF16_ALIGNED]. 4371** </ul>)^ 4372** ^The eTextRep argument determines the encoding of strings passed 4373** to the collating function callback, xCallback. 4374** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4375** force strings to be UTF16 with native byte order. 4376** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4377** on an even byte address. 4378** 4379** ^The fourth argument, pArg, is an application data pointer that is passed 4380** through as the first argument to the collating function callback. 4381** 4382** ^The fifth argument, xCallback, is a pointer to the collating function. 4383** ^Multiple collating functions can be registered using the same name but 4384** with different eTextRep parameters and SQLite will use whichever 4385** function requires the least amount of data transformation. 4386** ^If the xCallback argument is NULL then the collating function is 4387** deleted. ^When all collating functions having the same name are deleted, 4388** that collation is no longer usable. 4389** 4390** ^The collating function callback is invoked with a copy of the pArg 4391** application data pointer and with two strings in the encoding specified 4392** by the eTextRep argument. The collating function must return an 4393** integer that is negative, zero, or positive 4394** if the first string is less than, equal to, or greater than the second, 4395** respectively. A collating function must always return the same answer 4396** given the same inputs. If two or more collating functions are registered 4397** to the same collation name (using different eTextRep values) then all 4398** must give an equivalent answer when invoked with equivalent strings. 4399** The collating function must obey the following properties for all 4400** strings A, B, and C: 4401** 4402** <ol> 4403** <li> If A==B then B==A. 4404** <li> If A==B and B==C then A==C. 4405** <li> If A<B THEN B>A. 4406** <li> If A<B and B<C then A<C. 4407** </ol> 4408** 4409** If a collating function fails any of the above constraints and that 4410** collating function is registered and used, then the behavior of SQLite 4411** is undefined. 4412** 4413** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4414** with the addition that the xDestroy callback is invoked on pArg when 4415** the collating function is deleted. 4416** ^Collating functions are deleted when they are overridden by later 4417** calls to the collation creation functions or when the 4418** [database connection] is closed using [sqlite3_close()]. 4419** 4420** ^The xDestroy callback is <u>not</u> called if the 4421** sqlite3_create_collation_v2() function fails. Applications that invoke 4422** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4423** check the return code and dispose of the application data pointer 4424** themselves rather than expecting SQLite to deal with it for them. 4425** This is different from every other SQLite interface. The inconsistency 4426** is unfortunate but cannot be changed without breaking backwards 4427** compatibility. 4428** 4429** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4430*/ 4431int sqlite3_create_collation( 4432 sqlite3*, 4433 const char *zName, 4434 int eTextRep, 4435 void *pArg, 4436 int(*xCompare)(void*,int,const void*,int,const void*) 4437); 4438int sqlite3_create_collation_v2( 4439 sqlite3*, 4440 const char *zName, 4441 int eTextRep, 4442 void *pArg, 4443 int(*xCompare)(void*,int,const void*,int,const void*), 4444 void(*xDestroy)(void*) 4445); 4446int sqlite3_create_collation16( 4447 sqlite3*, 4448 const void *zName, 4449 int eTextRep, 4450 void *pArg, 4451 int(*xCompare)(void*,int,const void*,int,const void*) 4452); 4453 4454/* 4455** CAPI3REF: Collation Needed Callbacks 4456** 4457** ^To avoid having to register all collation sequences before a database 4458** can be used, a single callback function may be registered with the 4459** [database connection] to be invoked whenever an undefined collation 4460** sequence is required. 4461** 4462** ^If the function is registered using the sqlite3_collation_needed() API, 4463** then it is passed the names of undefined collation sequences as strings 4464** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4465** the names are passed as UTF-16 in machine native byte order. 4466** ^A call to either function replaces the existing collation-needed callback. 4467** 4468** ^(When the callback is invoked, the first argument passed is a copy 4469** of the second argument to sqlite3_collation_needed() or 4470** sqlite3_collation_needed16(). The second argument is the database 4471** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4472** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4473** sequence function required. The fourth parameter is the name of the 4474** required collation sequence.)^ 4475** 4476** The callback function should register the desired collation using 4477** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4478** [sqlite3_create_collation_v2()]. 4479*/ 4480int sqlite3_collation_needed( 4481 sqlite3*, 4482 void*, 4483 void(*)(void*,sqlite3*,int eTextRep,const char*) 4484); 4485int sqlite3_collation_needed16( 4486 sqlite3*, 4487 void*, 4488 void(*)(void*,sqlite3*,int eTextRep,const void*) 4489); 4490 4491#ifdef SQLITE_HAS_CODEC 4492/* 4493** Specify the key for an encrypted database. This routine should be 4494** called right after sqlite3_open(). 4495** 4496** The code to implement this API is not available in the public release 4497** of SQLite. 4498*/ 4499int sqlite3_key( 4500 sqlite3 *db, /* Database to be rekeyed */ 4501 const void *pKey, int nKey /* The key */ 4502); 4503 4504/* 4505** Change the key on an open database. If the current database is not 4506** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4507** database is decrypted. 4508** 4509** The code to implement this API is not available in the public release 4510** of SQLite. 4511*/ 4512int sqlite3_rekey( 4513 sqlite3 *db, /* Database to be rekeyed */ 4514 const void *pKey, int nKey /* The new key */ 4515); 4516 4517/* 4518** Specify the activation key for a SEE database. Unless 4519** activated, none of the SEE routines will work. 4520*/ 4521void sqlite3_activate_see( 4522 const char *zPassPhrase /* Activation phrase */ 4523); 4524#endif 4525 4526#ifdef SQLITE_ENABLE_CEROD 4527/* 4528** Specify the activation key for a CEROD database. Unless 4529** activated, none of the CEROD routines will work. 4530*/ 4531void sqlite3_activate_cerod( 4532 const char *zPassPhrase /* Activation phrase */ 4533); 4534#endif 4535 4536/* 4537** CAPI3REF: Suspend Execution For A Short Time 4538** 4539** The sqlite3_sleep() function causes the current thread to suspend execution 4540** for at least a number of milliseconds specified in its parameter. 4541** 4542** If the operating system does not support sleep requests with 4543** millisecond time resolution, then the time will be rounded up to 4544** the nearest second. The number of milliseconds of sleep actually 4545** requested from the operating system is returned. 4546** 4547** ^SQLite implements this interface by calling the xSleep() 4548** method of the default [sqlite3_vfs] object. If the xSleep() method 4549** of the default VFS is not implemented correctly, or not implemented at 4550** all, then the behavior of sqlite3_sleep() may deviate from the description 4551** in the previous paragraphs. 4552*/ 4553int sqlite3_sleep(int); 4554 4555/* 4556** CAPI3REF: Name Of The Folder Holding Temporary Files 4557** 4558** ^(If this global variable is made to point to a string which is 4559** the name of a folder (a.k.a. directory), then all temporary files 4560** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4561** will be placed in that directory.)^ ^If this variable 4562** is a NULL pointer, then SQLite performs a search for an appropriate 4563** temporary file directory. 4564** 4565** It is not safe to read or modify this variable in more than one 4566** thread at a time. It is not safe to read or modify this variable 4567** if a [database connection] is being used at the same time in a separate 4568** thread. 4569** It is intended that this variable be set once 4570** as part of process initialization and before any SQLite interface 4571** routines have been called and that this variable remain unchanged 4572** thereafter. 4573** 4574** ^The [temp_store_directory pragma] may modify this variable and cause 4575** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4576** the [temp_store_directory pragma] always assumes that any string 4577** that this variable points to is held in memory obtained from 4578** [sqlite3_malloc] and the pragma may attempt to free that memory 4579** using [sqlite3_free]. 4580** Hence, if this variable is modified directly, either it should be 4581** made NULL or made to point to memory obtained from [sqlite3_malloc] 4582** or else the use of the [temp_store_directory pragma] should be avoided. 4583** 4584** <b>Note to Windows Runtime users:</b> The temporary directory must be set 4585** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 4586** features that require the use of temporary files may fail. Here is an 4587** example of how to do this using C++ with the Windows Runtime: 4588** 4589** <blockquote><pre> 4590** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 4591** TemporaryFolder->Path->Data(); 4592** char zPathBuf[MAX_PATH + 1]; 4593** memset(zPathBuf, 0, sizeof(zPathBuf)); 4594** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 4595** NULL, NULL); 4596** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 4597** </pre></blockquote> 4598*/ 4599SQLITE_EXTERN char *sqlite3_temp_directory; 4600 4601/* 4602** CAPI3REF: Name Of The Folder Holding Database Files 4603** 4604** ^(If this global variable is made to point to a string which is 4605** the name of a folder (a.k.a. directory), then all database files 4606** specified with a relative pathname and created or accessed by 4607** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 4608** to be relative to that directory.)^ ^If this variable is a NULL 4609** pointer, then SQLite assumes that all database files specified 4610** with a relative pathname are relative to the current directory 4611** for the process. Only the windows VFS makes use of this global 4612** variable; it is ignored by the unix VFS. 4613** 4614** Changing the value of this variable while a database connection is 4615** open can result in a corrupt database. 4616** 4617** It is not safe to read or modify this variable in more than one 4618** thread at a time. It is not safe to read or modify this variable 4619** if a [database connection] is being used at the same time in a separate 4620** thread. 4621** It is intended that this variable be set once 4622** as part of process initialization and before any SQLite interface 4623** routines have been called and that this variable remain unchanged 4624** thereafter. 4625** 4626** ^The [data_store_directory pragma] may modify this variable and cause 4627** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4628** the [data_store_directory pragma] always assumes that any string 4629** that this variable points to is held in memory obtained from 4630** [sqlite3_malloc] and the pragma may attempt to free that memory 4631** using [sqlite3_free]. 4632** Hence, if this variable is modified directly, either it should be 4633** made NULL or made to point to memory obtained from [sqlite3_malloc] 4634** or else the use of the [data_store_directory pragma] should be avoided. 4635*/ 4636SQLITE_EXTERN char *sqlite3_data_directory; 4637 4638/* 4639** CAPI3REF: Test For Auto-Commit Mode 4640** KEYWORDS: {autocommit mode} 4641** 4642** ^The sqlite3_get_autocommit() interface returns non-zero or 4643** zero if the given database connection is or is not in autocommit mode, 4644** respectively. ^Autocommit mode is on by default. 4645** ^Autocommit mode is disabled by a [BEGIN] statement. 4646** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 4647** 4648** If certain kinds of errors occur on a statement within a multi-statement 4649** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 4650** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 4651** transaction might be rolled back automatically. The only way to 4652** find out whether SQLite automatically rolled back the transaction after 4653** an error is to use this function. 4654** 4655** If another thread changes the autocommit status of the database 4656** connection while this routine is running, then the return value 4657** is undefined. 4658*/ 4659int sqlite3_get_autocommit(sqlite3*); 4660 4661/* 4662** CAPI3REF: Find The Database Handle Of A Prepared Statement 4663** 4664** ^The sqlite3_db_handle interface returns the [database connection] handle 4665** to which a [prepared statement] belongs. ^The [database connection] 4666** returned by sqlite3_db_handle is the same [database connection] 4667** that was the first argument 4668** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 4669** create the statement in the first place. 4670*/ 4671sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 4672 4673/* 4674** CAPI3REF: Return The Filename For A Database Connection 4675** 4676** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 4677** associated with database N of connection D. ^The main database file 4678** has the name "main". If there is no attached database N on the database 4679** connection D, or if database N is a temporary or in-memory database, then 4680** a NULL pointer is returned. 4681** 4682** ^The filename returned by this function is the output of the 4683** xFullPathname method of the [VFS]. ^In other words, the filename 4684** will be an absolute pathname, even if the filename used 4685** to open the database originally was a URI or relative pathname. 4686*/ 4687const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 4688 4689/* 4690** CAPI3REF: Determine if a database is read-only 4691** 4692** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 4693** of connection D is read-only, 0 if it is read/write, or -1 if N is not 4694** the name of a database on connection D. 4695*/ 4696int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 4697 4698/* 4699** CAPI3REF: Find the next prepared statement 4700** 4701** ^This interface returns a pointer to the next [prepared statement] after 4702** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 4703** then this interface returns a pointer to the first prepared statement 4704** associated with the database connection pDb. ^If no prepared statement 4705** satisfies the conditions of this routine, it returns NULL. 4706** 4707** The [database connection] pointer D in a call to 4708** [sqlite3_next_stmt(D,S)] must refer to an open database 4709** connection and in particular must not be a NULL pointer. 4710*/ 4711sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 4712 4713/* 4714** CAPI3REF: Commit And Rollback Notification Callbacks 4715** 4716** ^The sqlite3_commit_hook() interface registers a callback 4717** function to be invoked whenever a transaction is [COMMIT | committed]. 4718** ^Any callback set by a previous call to sqlite3_commit_hook() 4719** for the same database connection is overridden. 4720** ^The sqlite3_rollback_hook() interface registers a callback 4721** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 4722** ^Any callback set by a previous call to sqlite3_rollback_hook() 4723** for the same database connection is overridden. 4724** ^The pArg argument is passed through to the callback. 4725** ^If the callback on a commit hook function returns non-zero, 4726** then the commit is converted into a rollback. 4727** 4728** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 4729** return the P argument from the previous call of the same function 4730** on the same [database connection] D, or NULL for 4731** the first call for each function on D. 4732** 4733** The commit and rollback hook callbacks are not reentrant. 4734** The callback implementation must not do anything that will modify 4735** the database connection that invoked the callback. Any actions 4736** to modify the database connection must be deferred until after the 4737** completion of the [sqlite3_step()] call that triggered the commit 4738** or rollback hook in the first place. 4739** Note that running any other SQL statements, including SELECT statements, 4740** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 4741** the database connections for the meaning of "modify" in this paragraph. 4742** 4743** ^Registering a NULL function disables the callback. 4744** 4745** ^When the commit hook callback routine returns zero, the [COMMIT] 4746** operation is allowed to continue normally. ^If the commit hook 4747** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 4748** ^The rollback hook is invoked on a rollback that results from a commit 4749** hook returning non-zero, just as it would be with any other rollback. 4750** 4751** ^For the purposes of this API, a transaction is said to have been 4752** rolled back if an explicit "ROLLBACK" statement is executed, or 4753** an error or constraint causes an implicit rollback to occur. 4754** ^The rollback callback is not invoked if a transaction is 4755** automatically rolled back because the database connection is closed. 4756** 4757** See also the [sqlite3_update_hook()] interface. 4758*/ 4759void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 4760void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 4761 4762/* 4763** CAPI3REF: Data Change Notification Callbacks 4764** 4765** ^The sqlite3_update_hook() interface registers a callback function 4766** with the [database connection] identified by the first argument 4767** to be invoked whenever a row is updated, inserted or deleted. 4768** ^Any callback set by a previous call to this function 4769** for the same database connection is overridden. 4770** 4771** ^The second argument is a pointer to the function to invoke when a 4772** row is updated, inserted or deleted. 4773** ^The first argument to the callback is a copy of the third argument 4774** to sqlite3_update_hook(). 4775** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 4776** or [SQLITE_UPDATE], depending on the operation that caused the callback 4777** to be invoked. 4778** ^The third and fourth arguments to the callback contain pointers to the 4779** database and table name containing the affected row. 4780** ^The final callback parameter is the [rowid] of the row. 4781** ^In the case of an update, this is the [rowid] after the update takes place. 4782** 4783** ^(The update hook is not invoked when internal system tables are 4784** modified (i.e. sqlite_master and sqlite_sequence).)^ 4785** 4786** ^In the current implementation, the update hook 4787** is not invoked when duplication rows are deleted because of an 4788** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 4789** invoked when rows are deleted using the [truncate optimization]. 4790** The exceptions defined in this paragraph might change in a future 4791** release of SQLite. 4792** 4793** The update hook implementation must not do anything that will modify 4794** the database connection that invoked the update hook. Any actions 4795** to modify the database connection must be deferred until after the 4796** completion of the [sqlite3_step()] call that triggered the update hook. 4797** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4798** database connections for the meaning of "modify" in this paragraph. 4799** 4800** ^The sqlite3_update_hook(D,C,P) function 4801** returns the P argument from the previous call 4802** on the same [database connection] D, or NULL for 4803** the first call on D. 4804** 4805** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4806** interfaces. 4807*/ 4808void *sqlite3_update_hook( 4809 sqlite3*, 4810 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4811 void* 4812); 4813 4814/* 4815** CAPI3REF: Enable Or Disable Shared Pager Cache 4816** 4817** ^(This routine enables or disables the sharing of the database cache 4818** and schema data structures between [database connection | connections] 4819** to the same database. Sharing is enabled if the argument is true 4820** and disabled if the argument is false.)^ 4821** 4822** ^Cache sharing is enabled and disabled for an entire process. 4823** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4824** sharing was enabled or disabled for each thread separately. 4825** 4826** ^(The cache sharing mode set by this interface effects all subsequent 4827** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4828** Existing database connections continue use the sharing mode 4829** that was in effect at the time they were opened.)^ 4830** 4831** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4832** successfully. An [error code] is returned otherwise.)^ 4833** 4834** ^Shared cache is disabled by default. But this might change in 4835** future releases of SQLite. Applications that care about shared 4836** cache setting should set it explicitly. 4837** 4838** This interface is threadsafe on processors where writing a 4839** 32-bit integer is atomic. 4840** 4841** See Also: [SQLite Shared-Cache Mode] 4842*/ 4843int sqlite3_enable_shared_cache(int); 4844 4845/* 4846** CAPI3REF: Attempt To Free Heap Memory 4847** 4848** ^The sqlite3_release_memory() interface attempts to free N bytes 4849** of heap memory by deallocating non-essential memory allocations 4850** held by the database library. Memory used to cache database 4851** pages to improve performance is an example of non-essential memory. 4852** ^sqlite3_release_memory() returns the number of bytes actually freed, 4853** which might be more or less than the amount requested. 4854** ^The sqlite3_release_memory() routine is a no-op returning zero 4855** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4856** 4857** See also: [sqlite3_db_release_memory()] 4858*/ 4859int sqlite3_release_memory(int); 4860 4861/* 4862** CAPI3REF: Free Memory Used By A Database Connection 4863** 4864** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 4865** memory as possible from database connection D. Unlike the 4866** [sqlite3_release_memory()] interface, this interface is effect even 4867** when then [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 4868** omitted. 4869** 4870** See also: [sqlite3_release_memory()] 4871*/ 4872int sqlite3_db_release_memory(sqlite3*); 4873 4874/* 4875** CAPI3REF: Impose A Limit On Heap Size 4876** 4877** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 4878** soft limit on the amount of heap memory that may be allocated by SQLite. 4879** ^SQLite strives to keep heap memory utilization below the soft heap 4880** limit by reducing the number of pages held in the page cache 4881** as heap memory usages approaches the limit. 4882** ^The soft heap limit is "soft" because even though SQLite strives to stay 4883** below the limit, it will exceed the limit rather than generate 4884** an [SQLITE_NOMEM] error. In other words, the soft heap limit 4885** is advisory only. 4886** 4887** ^The return value from sqlite3_soft_heap_limit64() is the size of 4888** the soft heap limit prior to the call, or negative in the case of an 4889** error. ^If the argument N is negative 4890** then no change is made to the soft heap limit. Hence, the current 4891** size of the soft heap limit can be determined by invoking 4892** sqlite3_soft_heap_limit64() with a negative argument. 4893** 4894** ^If the argument N is zero then the soft heap limit is disabled. 4895** 4896** ^(The soft heap limit is not enforced in the current implementation 4897** if one or more of following conditions are true: 4898** 4899** <ul> 4900** <li> The soft heap limit is set to zero. 4901** <li> Memory accounting is disabled using a combination of the 4902** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 4903** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 4904** <li> An alternative page cache implementation is specified using 4905** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 4906** <li> The page cache allocates from its own memory pool supplied 4907** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 4908** from the heap. 4909** </ul>)^ 4910** 4911** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 4912** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 4913** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 4914** the soft heap limit is enforced on every memory allocation. Without 4915** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 4916** when memory is allocated by the page cache. Testing suggests that because 4917** the page cache is the predominate memory user in SQLite, most 4918** applications will achieve adequate soft heap limit enforcement without 4919** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4920** 4921** The circumstances under which SQLite will enforce the soft heap limit may 4922** changes in future releases of SQLite. 4923*/ 4924sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 4925 4926/* 4927** CAPI3REF: Deprecated Soft Heap Limit Interface 4928** DEPRECATED 4929** 4930** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 4931** interface. This routine is provided for historical compatibility 4932** only. All new applications should use the 4933** [sqlite3_soft_heap_limit64()] interface rather than this one. 4934*/ 4935SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 4936 4937 4938/* 4939** CAPI3REF: Extract Metadata About A Column Of A Table 4940** 4941** ^This routine returns metadata about a specific column of a specific 4942** database table accessible using the [database connection] handle 4943** passed as the first function argument. 4944** 4945** ^The column is identified by the second, third and fourth parameters to 4946** this function. ^The second parameter is either the name of the database 4947** (i.e. "main", "temp", or an attached database) containing the specified 4948** table or NULL. ^If it is NULL, then all attached databases are searched 4949** for the table using the same algorithm used by the database engine to 4950** resolve unqualified table references. 4951** 4952** ^The third and fourth parameters to this function are the table and column 4953** name of the desired column, respectively. Neither of these parameters 4954** may be NULL. 4955** 4956** ^Metadata is returned by writing to the memory locations passed as the 5th 4957** and subsequent parameters to this function. ^Any of these arguments may be 4958** NULL, in which case the corresponding element of metadata is omitted. 4959** 4960** ^(<blockquote> 4961** <table border="1"> 4962** <tr><th> Parameter <th> Output<br>Type <th> Description 4963** 4964** <tr><td> 5th <td> const char* <td> Data type 4965** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4966** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4967** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4968** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4969** </table> 4970** </blockquote>)^ 4971** 4972** ^The memory pointed to by the character pointers returned for the 4973** declaration type and collation sequence is valid only until the next 4974** call to any SQLite API function. 4975** 4976** ^If the specified table is actually a view, an [error code] is returned. 4977** 4978** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4979** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4980** parameters are set for the explicitly declared column. ^(If there is no 4981** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4982** parameters are set as follows: 4983** 4984** <pre> 4985** data type: "INTEGER" 4986** collation sequence: "BINARY" 4987** not null: 0 4988** primary key: 1 4989** auto increment: 0 4990** </pre>)^ 4991** 4992** ^(This function may load one or more schemas from database files. If an 4993** error occurs during this process, or if the requested table or column 4994** cannot be found, an [error code] is returned and an error message left 4995** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4996** 4997** ^This API is only available if the library was compiled with the 4998** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4999*/ 5000int sqlite3_table_column_metadata( 5001 sqlite3 *db, /* Connection handle */ 5002 const char *zDbName, /* Database name or NULL */ 5003 const char *zTableName, /* Table name */ 5004 const char *zColumnName, /* Column name */ 5005 char const **pzDataType, /* OUTPUT: Declared data type */ 5006 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5007 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5008 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5009 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5010); 5011 5012/* 5013** CAPI3REF: Load An Extension 5014** 5015** ^This interface loads an SQLite extension library from the named file. 5016** 5017** ^The sqlite3_load_extension() interface attempts to load an 5018** SQLite extension library contained in the file zFile. 5019** 5020** ^The entry point is zProc. 5021** ^zProc may be 0, in which case the name of the entry point 5022** defaults to "sqlite3_extension_init". 5023** ^The sqlite3_load_extension() interface returns 5024** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5025** ^If an error occurs and pzErrMsg is not 0, then the 5026** [sqlite3_load_extension()] interface shall attempt to 5027** fill *pzErrMsg with error message text stored in memory 5028** obtained from [sqlite3_malloc()]. The calling function 5029** should free this memory by calling [sqlite3_free()]. 5030** 5031** ^Extension loading must be enabled using 5032** [sqlite3_enable_load_extension()] prior to calling this API, 5033** otherwise an error will be returned. 5034** 5035** See also the [load_extension() SQL function]. 5036*/ 5037int sqlite3_load_extension( 5038 sqlite3 *db, /* Load the extension into this database connection */ 5039 const char *zFile, /* Name of the shared library containing extension */ 5040 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5041 char **pzErrMsg /* Put error message here if not 0 */ 5042); 5043 5044/* 5045** CAPI3REF: Enable Or Disable Extension Loading 5046** 5047** ^So as not to open security holes in older applications that are 5048** unprepared to deal with extension loading, and as a means of disabling 5049** extension loading while evaluating user-entered SQL, the following API 5050** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5051** 5052** ^Extension loading is off by default. See ticket #1863. 5053** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5054** to turn extension loading on and call it with onoff==0 to turn 5055** it back off again. 5056*/ 5057int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5058 5059/* 5060** CAPI3REF: Automatically Load Statically Linked Extensions 5061** 5062** ^This interface causes the xEntryPoint() function to be invoked for 5063** each new [database connection] that is created. The idea here is that 5064** xEntryPoint() is the entry point for a statically linked SQLite extension 5065** that is to be automatically loaded into all new database connections. 5066** 5067** ^(Even though the function prototype shows that xEntryPoint() takes 5068** no arguments and returns void, SQLite invokes xEntryPoint() with three 5069** arguments and expects and integer result as if the signature of the 5070** entry point where as follows: 5071** 5072** <blockquote><pre> 5073** int xEntryPoint( 5074** sqlite3 *db, 5075** const char **pzErrMsg, 5076** const struct sqlite3_api_routines *pThunk 5077** ); 5078** </pre></blockquote>)^ 5079** 5080** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5081** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5082** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5083** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5084** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5085** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5086** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 5087** 5088** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 5089** on the list of automatic extensions is a harmless no-op. ^No entry point 5090** will be called more than once for each database connection that is opened. 5091** 5092** See also: [sqlite3_reset_auto_extension()]. 5093*/ 5094int sqlite3_auto_extension(void (*xEntryPoint)(void)); 5095 5096/* 5097** CAPI3REF: Reset Automatic Extension Loading 5098** 5099** ^This interface disables all automatic extensions previously 5100** registered using [sqlite3_auto_extension()]. 5101*/ 5102void sqlite3_reset_auto_extension(void); 5103 5104/* 5105** The interface to the virtual-table mechanism is currently considered 5106** to be experimental. The interface might change in incompatible ways. 5107** If this is a problem for you, do not use the interface at this time. 5108** 5109** When the virtual-table mechanism stabilizes, we will declare the 5110** interface fixed, support it indefinitely, and remove this comment. 5111*/ 5112 5113/* 5114** Structures used by the virtual table interface 5115*/ 5116typedef struct sqlite3_vtab sqlite3_vtab; 5117typedef struct sqlite3_index_info sqlite3_index_info; 5118typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 5119typedef struct sqlite3_module sqlite3_module; 5120 5121/* 5122** CAPI3REF: Virtual Table Object 5123** KEYWORDS: sqlite3_module {virtual table module} 5124** 5125** This structure, sometimes called a "virtual table module", 5126** defines the implementation of a [virtual tables]. 5127** This structure consists mostly of methods for the module. 5128** 5129** ^A virtual table module is created by filling in a persistent 5130** instance of this structure and passing a pointer to that instance 5131** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 5132** ^The registration remains valid until it is replaced by a different 5133** module or until the [database connection] closes. The content 5134** of this structure must not change while it is registered with 5135** any database connection. 5136*/ 5137struct sqlite3_module { 5138 int iVersion; 5139 int (*xCreate)(sqlite3*, void *pAux, 5140 int argc, const char *const*argv, 5141 sqlite3_vtab **ppVTab, char**); 5142 int (*xConnect)(sqlite3*, void *pAux, 5143 int argc, const char *const*argv, 5144 sqlite3_vtab **ppVTab, char**); 5145 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 5146 int (*xDisconnect)(sqlite3_vtab *pVTab); 5147 int (*xDestroy)(sqlite3_vtab *pVTab); 5148 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 5149 int (*xClose)(sqlite3_vtab_cursor*); 5150 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 5151 int argc, sqlite3_value **argv); 5152 int (*xNext)(sqlite3_vtab_cursor*); 5153 int (*xEof)(sqlite3_vtab_cursor*); 5154 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 5155 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 5156 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 5157 int (*xBegin)(sqlite3_vtab *pVTab); 5158 int (*xSync)(sqlite3_vtab *pVTab); 5159 int (*xCommit)(sqlite3_vtab *pVTab); 5160 int (*xRollback)(sqlite3_vtab *pVTab); 5161 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 5162 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 5163 void **ppArg); 5164 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 5165 /* The methods above are in version 1 of the sqlite_module object. Those 5166 ** below are for version 2 and greater. */ 5167 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 5168 int (*xRelease)(sqlite3_vtab *pVTab, int); 5169 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 5170}; 5171 5172/* 5173** CAPI3REF: Virtual Table Indexing Information 5174** KEYWORDS: sqlite3_index_info 5175** 5176** The sqlite3_index_info structure and its substructures is used as part 5177** of the [virtual table] interface to 5178** pass information into and receive the reply from the [xBestIndex] 5179** method of a [virtual table module]. The fields under **Inputs** are the 5180** inputs to xBestIndex and are read-only. xBestIndex inserts its 5181** results into the **Outputs** fields. 5182** 5183** ^(The aConstraint[] array records WHERE clause constraints of the form: 5184** 5185** <blockquote>column OP expr</blockquote> 5186** 5187** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 5188** stored in aConstraint[].op using one of the 5189** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 5190** ^(The index of the column is stored in 5191** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5192** expr on the right-hand side can be evaluated (and thus the constraint 5193** is usable) and false if it cannot.)^ 5194** 5195** ^The optimizer automatically inverts terms of the form "expr OP column" 5196** and makes other simplifications to the WHERE clause in an attempt to 5197** get as many WHERE clause terms into the form shown above as possible. 5198** ^The aConstraint[] array only reports WHERE clause terms that are 5199** relevant to the particular virtual table being queried. 5200** 5201** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5202** ^Each term of aOrderBy records a column of the ORDER BY clause. 5203** 5204** The [xBestIndex] method must fill aConstraintUsage[] with information 5205** about what parameters to pass to xFilter. ^If argvIndex>0 then 5206** the right-hand side of the corresponding aConstraint[] is evaluated 5207** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5208** is true, then the constraint is assumed to be fully handled by the 5209** virtual table and is not checked again by SQLite.)^ 5210** 5211** ^The idxNum and idxPtr values are recorded and passed into the 5212** [xFilter] method. 5213** ^[sqlite3_free()] is used to free idxPtr if and only if 5214** needToFreeIdxPtr is true. 5215** 5216** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5217** the correct order to satisfy the ORDER BY clause so that no separate 5218** sorting step is required. 5219** 5220** ^The estimatedCost value is an estimate of the cost of doing the 5221** particular lookup. A full scan of a table with N entries should have 5222** a cost of N. A binary search of a table of N entries should have a 5223** cost of approximately log(N). 5224*/ 5225struct sqlite3_index_info { 5226 /* Inputs */ 5227 int nConstraint; /* Number of entries in aConstraint */ 5228 struct sqlite3_index_constraint { 5229 int iColumn; /* Column on left-hand side of constraint */ 5230 unsigned char op; /* Constraint operator */ 5231 unsigned char usable; /* True if this constraint is usable */ 5232 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5233 } *aConstraint; /* Table of WHERE clause constraints */ 5234 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5235 struct sqlite3_index_orderby { 5236 int iColumn; /* Column number */ 5237 unsigned char desc; /* True for DESC. False for ASC. */ 5238 } *aOrderBy; /* The ORDER BY clause */ 5239 /* Outputs */ 5240 struct sqlite3_index_constraint_usage { 5241 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5242 unsigned char omit; /* Do not code a test for this constraint */ 5243 } *aConstraintUsage; 5244 int idxNum; /* Number used to identify the index */ 5245 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5246 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5247 int orderByConsumed; /* True if output is already ordered */ 5248 double estimatedCost; /* Estimated cost of using this index */ 5249}; 5250 5251/* 5252** CAPI3REF: Virtual Table Constraint Operator Codes 5253** 5254** These macros defined the allowed values for the 5255** [sqlite3_index_info].aConstraint[].op field. Each value represents 5256** an operator that is part of a constraint term in the wHERE clause of 5257** a query that uses a [virtual table]. 5258*/ 5259#define SQLITE_INDEX_CONSTRAINT_EQ 2 5260#define SQLITE_INDEX_CONSTRAINT_GT 4 5261#define SQLITE_INDEX_CONSTRAINT_LE 8 5262#define SQLITE_INDEX_CONSTRAINT_LT 16 5263#define SQLITE_INDEX_CONSTRAINT_GE 32 5264#define SQLITE_INDEX_CONSTRAINT_MATCH 64 5265 5266/* 5267** CAPI3REF: Register A Virtual Table Implementation 5268** 5269** ^These routines are used to register a new [virtual table module] name. 5270** ^Module names must be registered before 5271** creating a new [virtual table] using the module and before using a 5272** preexisting [virtual table] for the module. 5273** 5274** ^The module name is registered on the [database connection] specified 5275** by the first parameter. ^The name of the module is given by the 5276** second parameter. ^The third parameter is a pointer to 5277** the implementation of the [virtual table module]. ^The fourth 5278** parameter is an arbitrary client data pointer that is passed through 5279** into the [xCreate] and [xConnect] methods of the virtual table module 5280** when a new virtual table is be being created or reinitialized. 5281** 5282** ^The sqlite3_create_module_v2() interface has a fifth parameter which 5283** is a pointer to a destructor for the pClientData. ^SQLite will 5284** invoke the destructor function (if it is not NULL) when SQLite 5285** no longer needs the pClientData pointer. ^The destructor will also 5286** be invoked if the call to sqlite3_create_module_v2() fails. 5287** ^The sqlite3_create_module() 5288** interface is equivalent to sqlite3_create_module_v2() with a NULL 5289** destructor. 5290*/ 5291int sqlite3_create_module( 5292 sqlite3 *db, /* SQLite connection to register module with */ 5293 const char *zName, /* Name of the module */ 5294 const sqlite3_module *p, /* Methods for the module */ 5295 void *pClientData /* Client data for xCreate/xConnect */ 5296); 5297int sqlite3_create_module_v2( 5298 sqlite3 *db, /* SQLite connection to register module with */ 5299 const char *zName, /* Name of the module */ 5300 const sqlite3_module *p, /* Methods for the module */ 5301 void *pClientData, /* Client data for xCreate/xConnect */ 5302 void(*xDestroy)(void*) /* Module destructor function */ 5303); 5304 5305/* 5306** CAPI3REF: Virtual Table Instance Object 5307** KEYWORDS: sqlite3_vtab 5308** 5309** Every [virtual table module] implementation uses a subclass 5310** of this object to describe a particular instance 5311** of the [virtual table]. Each subclass will 5312** be tailored to the specific needs of the module implementation. 5313** The purpose of this superclass is to define certain fields that are 5314** common to all module implementations. 5315** 5316** ^Virtual tables methods can set an error message by assigning a 5317** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 5318** take care that any prior string is freed by a call to [sqlite3_free()] 5319** prior to assigning a new string to zErrMsg. ^After the error message 5320** is delivered up to the client application, the string will be automatically 5321** freed by sqlite3_free() and the zErrMsg field will be zeroed. 5322*/ 5323struct sqlite3_vtab { 5324 const sqlite3_module *pModule; /* The module for this virtual table */ 5325 int nRef; /* NO LONGER USED */ 5326 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 5327 /* Virtual table implementations will typically add additional fields */ 5328}; 5329 5330/* 5331** CAPI3REF: Virtual Table Cursor Object 5332** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 5333** 5334** Every [virtual table module] implementation uses a subclass of the 5335** following structure to describe cursors that point into the 5336** [virtual table] and are used 5337** to loop through the virtual table. Cursors are created using the 5338** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 5339** by the [sqlite3_module.xClose | xClose] method. Cursors are used 5340** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 5341** of the module. Each module implementation will define 5342** the content of a cursor structure to suit its own needs. 5343** 5344** This superclass exists in order to define fields of the cursor that 5345** are common to all implementations. 5346*/ 5347struct sqlite3_vtab_cursor { 5348 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 5349 /* Virtual table implementations will typically add additional fields */ 5350}; 5351 5352/* 5353** CAPI3REF: Declare The Schema Of A Virtual Table 5354** 5355** ^The [xCreate] and [xConnect] methods of a 5356** [virtual table module] call this interface 5357** to declare the format (the names and datatypes of the columns) of 5358** the virtual tables they implement. 5359*/ 5360int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 5361 5362/* 5363** CAPI3REF: Overload A Function For A Virtual Table 5364** 5365** ^(Virtual tables can provide alternative implementations of functions 5366** using the [xFindFunction] method of the [virtual table module]. 5367** But global versions of those functions 5368** must exist in order to be overloaded.)^ 5369** 5370** ^(This API makes sure a global version of a function with a particular 5371** name and number of parameters exists. If no such function exists 5372** before this API is called, a new function is created.)^ ^The implementation 5373** of the new function always causes an exception to be thrown. So 5374** the new function is not good for anything by itself. Its only 5375** purpose is to be a placeholder function that can be overloaded 5376** by a [virtual table]. 5377*/ 5378int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5379 5380/* 5381** The interface to the virtual-table mechanism defined above (back up 5382** to a comment remarkably similar to this one) is currently considered 5383** to be experimental. The interface might change in incompatible ways. 5384** If this is a problem for you, do not use the interface at this time. 5385** 5386** When the virtual-table mechanism stabilizes, we will declare the 5387** interface fixed, support it indefinitely, and remove this comment. 5388*/ 5389 5390/* 5391** CAPI3REF: A Handle To An Open BLOB 5392** KEYWORDS: {BLOB handle} {BLOB handles} 5393** 5394** An instance of this object represents an open BLOB on which 5395** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5396** ^Objects of this type are created by [sqlite3_blob_open()] 5397** and destroyed by [sqlite3_blob_close()]. 5398** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5399** can be used to read or write small subsections of the BLOB. 5400** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5401*/ 5402typedef struct sqlite3_blob sqlite3_blob; 5403 5404/* 5405** CAPI3REF: Open A BLOB For Incremental I/O 5406** 5407** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5408** in row iRow, column zColumn, table zTable in database zDb; 5409** in other words, the same BLOB that would be selected by: 5410** 5411** <pre> 5412** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5413** </pre>)^ 5414** 5415** ^If the flags parameter is non-zero, then the BLOB is opened for read 5416** and write access. ^If it is zero, the BLOB is opened for read access. 5417** ^It is not possible to open a column that is part of an index or primary 5418** key for writing. ^If [foreign key constraints] are enabled, it is 5419** not possible to open a column that is part of a [child key] for writing. 5420** 5421** ^Note that the database name is not the filename that contains 5422** the database but rather the symbolic name of the database that 5423** appears after the AS keyword when the database is connected using [ATTACH]. 5424** ^For the main database file, the database name is "main". 5425** ^For TEMP tables, the database name is "temp". 5426** 5427** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 5428** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 5429** to be a null pointer.)^ 5430** ^This function sets the [database connection] error code and message 5431** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 5432** functions. ^Note that the *ppBlob variable is always initialized in a 5433** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 5434** regardless of the success or failure of this routine. 5435** 5436** ^(If the row that a BLOB handle points to is modified by an 5437** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5438** then the BLOB handle is marked as "expired". 5439** This is true if any column of the row is changed, even a column 5440** other than the one the BLOB handle is open on.)^ 5441** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5442** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5443** ^(Changes written into a BLOB prior to the BLOB expiring are not 5444** rolled back by the expiration of the BLOB. Such changes will eventually 5445** commit if the transaction continues to completion.)^ 5446** 5447** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5448** the opened blob. ^The size of a blob may not be changed by this 5449** interface. Use the [UPDATE] SQL command to change the size of a 5450** blob. 5451** 5452** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5453** and the built-in [zeroblob] SQL function can be used, if desired, 5454** to create an empty, zero-filled blob in which to read or write using 5455** this interface. 5456** 5457** To avoid a resource leak, every open [BLOB handle] should eventually 5458** be released by a call to [sqlite3_blob_close()]. 5459*/ 5460int sqlite3_blob_open( 5461 sqlite3*, 5462 const char *zDb, 5463 const char *zTable, 5464 const char *zColumn, 5465 sqlite3_int64 iRow, 5466 int flags, 5467 sqlite3_blob **ppBlob 5468); 5469 5470/* 5471** CAPI3REF: Move a BLOB Handle to a New Row 5472** 5473** ^This function is used to move an existing blob handle so that it points 5474** to a different row of the same database table. ^The new row is identified 5475** by the rowid value passed as the second argument. Only the row can be 5476** changed. ^The database, table and column on which the blob handle is open 5477** remain the same. Moving an existing blob handle to a new row can be 5478** faster than closing the existing handle and opening a new one. 5479** 5480** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5481** it must exist and there must be either a blob or text value stored in 5482** the nominated column.)^ ^If the new row is not present in the table, or if 5483** it does not contain a blob or text value, or if another error occurs, an 5484** SQLite error code is returned and the blob handle is considered aborted. 5485** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5486** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5487** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5488** always returns zero. 5489** 5490** ^This function sets the database handle error code and message. 5491*/ 5492SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5493 5494/* 5495** CAPI3REF: Close A BLOB Handle 5496** 5497** ^Closes an open [BLOB handle]. 5498** 5499** ^Closing a BLOB shall cause the current transaction to commit 5500** if there are no other BLOBs, no pending prepared statements, and the 5501** database connection is in [autocommit mode]. 5502** ^If any writes were made to the BLOB, they might be held in cache 5503** until the close operation if they will fit. 5504** 5505** ^(Closing the BLOB often forces the changes 5506** out to disk and so if any I/O errors occur, they will likely occur 5507** at the time when the BLOB is closed. Any errors that occur during 5508** closing are reported as a non-zero return value.)^ 5509** 5510** ^(The BLOB is closed unconditionally. Even if this routine returns 5511** an error code, the BLOB is still closed.)^ 5512** 5513** ^Calling this routine with a null pointer (such as would be returned 5514** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 5515*/ 5516int sqlite3_blob_close(sqlite3_blob *); 5517 5518/* 5519** CAPI3REF: Return The Size Of An Open BLOB 5520** 5521** ^Returns the size in bytes of the BLOB accessible via the 5522** successfully opened [BLOB handle] in its only argument. ^The 5523** incremental blob I/O routines can only read or overwriting existing 5524** blob content; they cannot change the size of a blob. 5525** 5526** This routine only works on a [BLOB handle] which has been created 5527** by a prior successful call to [sqlite3_blob_open()] and which has not 5528** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5529** to this routine results in undefined and probably undesirable behavior. 5530*/ 5531int sqlite3_blob_bytes(sqlite3_blob *); 5532 5533/* 5534** CAPI3REF: Read Data From A BLOB Incrementally 5535** 5536** ^(This function is used to read data from an open [BLOB handle] into a 5537** caller-supplied buffer. N bytes of data are copied into buffer Z 5538** from the open BLOB, starting at offset iOffset.)^ 5539** 5540** ^If offset iOffset is less than N bytes from the end of the BLOB, 5541** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 5542** less than zero, [SQLITE_ERROR] is returned and no data is read. 5543** ^The size of the blob (and hence the maximum value of N+iOffset) 5544** can be determined using the [sqlite3_blob_bytes()] interface. 5545** 5546** ^An attempt to read from an expired [BLOB handle] fails with an 5547** error code of [SQLITE_ABORT]. 5548** 5549** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 5550** Otherwise, an [error code] or an [extended error code] is returned.)^ 5551** 5552** This routine only works on a [BLOB handle] which has been created 5553** by a prior successful call to [sqlite3_blob_open()] and which has not 5554** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5555** to this routine results in undefined and probably undesirable behavior. 5556** 5557** See also: [sqlite3_blob_write()]. 5558*/ 5559int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 5560 5561/* 5562** CAPI3REF: Write Data Into A BLOB Incrementally 5563** 5564** ^This function is used to write data into an open [BLOB handle] from a 5565** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 5566** into the open BLOB, starting at offset iOffset. 5567** 5568** ^If the [BLOB handle] passed as the first argument was not opened for 5569** writing (the flags parameter to [sqlite3_blob_open()] was zero), 5570** this function returns [SQLITE_READONLY]. 5571** 5572** ^This function may only modify the contents of the BLOB; it is 5573** not possible to increase the size of a BLOB using this API. 5574** ^If offset iOffset is less than N bytes from the end of the BLOB, 5575** [SQLITE_ERROR] is returned and no data is written. ^If N is 5576** less than zero [SQLITE_ERROR] is returned and no data is written. 5577** The size of the BLOB (and hence the maximum value of N+iOffset) 5578** can be determined using the [sqlite3_blob_bytes()] interface. 5579** 5580** ^An attempt to write to an expired [BLOB handle] fails with an 5581** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 5582** before the [BLOB handle] expired are not rolled back by the 5583** expiration of the handle, though of course those changes might 5584** have been overwritten by the statement that expired the BLOB handle 5585** or by other independent statements. 5586** 5587** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 5588** Otherwise, an [error code] or an [extended error code] is returned.)^ 5589** 5590** This routine only works on a [BLOB handle] which has been created 5591** by a prior successful call to [sqlite3_blob_open()] and which has not 5592** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5593** to this routine results in undefined and probably undesirable behavior. 5594** 5595** See also: [sqlite3_blob_read()]. 5596*/ 5597int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 5598 5599/* 5600** CAPI3REF: Virtual File System Objects 5601** 5602** A virtual filesystem (VFS) is an [sqlite3_vfs] object 5603** that SQLite uses to interact 5604** with the underlying operating system. Most SQLite builds come with a 5605** single default VFS that is appropriate for the host computer. 5606** New VFSes can be registered and existing VFSes can be unregistered. 5607** The following interfaces are provided. 5608** 5609** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 5610** ^Names are case sensitive. 5611** ^Names are zero-terminated UTF-8 strings. 5612** ^If there is no match, a NULL pointer is returned. 5613** ^If zVfsName is NULL then the default VFS is returned. 5614** 5615** ^New VFSes are registered with sqlite3_vfs_register(). 5616** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 5617** ^The same VFS can be registered multiple times without injury. 5618** ^To make an existing VFS into the default VFS, register it again 5619** with the makeDflt flag set. If two different VFSes with the 5620** same name are registered, the behavior is undefined. If a 5621** VFS is registered with a name that is NULL or an empty string, 5622** then the behavior is undefined. 5623** 5624** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 5625** ^(If the default VFS is unregistered, another VFS is chosen as 5626** the default. The choice for the new VFS is arbitrary.)^ 5627*/ 5628sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 5629int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 5630int sqlite3_vfs_unregister(sqlite3_vfs*); 5631 5632/* 5633** CAPI3REF: Mutexes 5634** 5635** The SQLite core uses these routines for thread 5636** synchronization. Though they are intended for internal 5637** use by SQLite, code that links against SQLite is 5638** permitted to use any of these routines. 5639** 5640** The SQLite source code contains multiple implementations 5641** of these mutex routines. An appropriate implementation 5642** is selected automatically at compile-time. ^(The following 5643** implementations are available in the SQLite core: 5644** 5645** <ul> 5646** <li> SQLITE_MUTEX_PTHREADS 5647** <li> SQLITE_MUTEX_W32 5648** <li> SQLITE_MUTEX_NOOP 5649** </ul>)^ 5650** 5651** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 5652** that does no real locking and is appropriate for use in 5653** a single-threaded application. ^The SQLITE_MUTEX_PTHREADS and 5654** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 5655** and Windows. 5656** 5657** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 5658** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 5659** implementation is included with the library. In this case the 5660** application must supply a custom mutex implementation using the 5661** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 5662** before calling sqlite3_initialize() or any other public sqlite3_ 5663** function that calls sqlite3_initialize().)^ 5664** 5665** ^The sqlite3_mutex_alloc() routine allocates a new 5666** mutex and returns a pointer to it. ^If it returns NULL 5667** that means that a mutex could not be allocated. ^SQLite 5668** will unwind its stack and return an error. ^(The argument 5669** to sqlite3_mutex_alloc() is one of these integer constants: 5670** 5671** <ul> 5672** <li> SQLITE_MUTEX_FAST 5673** <li> SQLITE_MUTEX_RECURSIVE 5674** <li> SQLITE_MUTEX_STATIC_MASTER 5675** <li> SQLITE_MUTEX_STATIC_MEM 5676** <li> SQLITE_MUTEX_STATIC_MEM2 5677** <li> SQLITE_MUTEX_STATIC_PRNG 5678** <li> SQLITE_MUTEX_STATIC_LRU 5679** <li> SQLITE_MUTEX_STATIC_LRU2 5680** </ul>)^ 5681** 5682** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 5683** cause sqlite3_mutex_alloc() to create 5684** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 5685** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 5686** The mutex implementation does not need to make a distinction 5687** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 5688** not want to. ^SQLite will only request a recursive mutex in 5689** cases where it really needs one. ^If a faster non-recursive mutex 5690** implementation is available on the host platform, the mutex subsystem 5691** might return such a mutex in response to SQLITE_MUTEX_FAST. 5692** 5693** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 5694** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 5695** a pointer to a static preexisting mutex. ^Six static mutexes are 5696** used by the current version of SQLite. Future versions of SQLite 5697** may add additional static mutexes. Static mutexes are for internal 5698** use by SQLite only. Applications that use SQLite mutexes should 5699** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 5700** SQLITE_MUTEX_RECURSIVE. 5701** 5702** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 5703** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 5704** returns a different mutex on every call. ^But for the static 5705** mutex types, the same mutex is returned on every call that has 5706** the same type number. 5707** 5708** ^The sqlite3_mutex_free() routine deallocates a previously 5709** allocated dynamic mutex. ^SQLite is careful to deallocate every 5710** dynamic mutex that it allocates. The dynamic mutexes must not be in 5711** use when they are deallocated. Attempting to deallocate a static 5712** mutex results in undefined behavior. ^SQLite never deallocates 5713** a static mutex. 5714** 5715** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 5716** to enter a mutex. ^If another thread is already within the mutex, 5717** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 5718** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 5719** upon successful entry. ^(Mutexes created using 5720** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 5721** In such cases the, 5722** mutex must be exited an equal number of times before another thread 5723** can enter.)^ ^(If the same thread tries to enter any other 5724** kind of mutex more than once, the behavior is undefined. 5725** SQLite will never exhibit 5726** such behavior in its own use of mutexes.)^ 5727** 5728** ^(Some systems (for example, Windows 95) do not support the operation 5729** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 5730** will always return SQLITE_BUSY. The SQLite core only ever uses 5731** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 5732** 5733** ^The sqlite3_mutex_leave() routine exits a mutex that was 5734** previously entered by the same thread. ^(The behavior 5735** is undefined if the mutex is not currently entered by the 5736** calling thread or is not currently allocated. SQLite will 5737** never do either.)^ 5738** 5739** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 5740** sqlite3_mutex_leave() is a NULL pointer, then all three routines 5741** behave as no-ops. 5742** 5743** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 5744*/ 5745sqlite3_mutex *sqlite3_mutex_alloc(int); 5746void sqlite3_mutex_free(sqlite3_mutex*); 5747void sqlite3_mutex_enter(sqlite3_mutex*); 5748int sqlite3_mutex_try(sqlite3_mutex*); 5749void sqlite3_mutex_leave(sqlite3_mutex*); 5750 5751/* 5752** CAPI3REF: Mutex Methods Object 5753** 5754** An instance of this structure defines the low-level routines 5755** used to allocate and use mutexes. 5756** 5757** Usually, the default mutex implementations provided by SQLite are 5758** sufficient, however the user has the option of substituting a custom 5759** implementation for specialized deployments or systems for which SQLite 5760** does not provide a suitable implementation. In this case, the user 5761** creates and populates an instance of this structure to pass 5762** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 5763** Additionally, an instance of this structure can be used as an 5764** output variable when querying the system for the current mutex 5765** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 5766** 5767** ^The xMutexInit method defined by this structure is invoked as 5768** part of system initialization by the sqlite3_initialize() function. 5769** ^The xMutexInit routine is called by SQLite exactly once for each 5770** effective call to [sqlite3_initialize()]. 5771** 5772** ^The xMutexEnd method defined by this structure is invoked as 5773** part of system shutdown by the sqlite3_shutdown() function. The 5774** implementation of this method is expected to release all outstanding 5775** resources obtained by the mutex methods implementation, especially 5776** those obtained by the xMutexInit method. ^The xMutexEnd() 5777** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 5778** 5779** ^(The remaining seven methods defined by this structure (xMutexAlloc, 5780** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 5781** xMutexNotheld) implement the following interfaces (respectively): 5782** 5783** <ul> 5784** <li> [sqlite3_mutex_alloc()] </li> 5785** <li> [sqlite3_mutex_free()] </li> 5786** <li> [sqlite3_mutex_enter()] </li> 5787** <li> [sqlite3_mutex_try()] </li> 5788** <li> [sqlite3_mutex_leave()] </li> 5789** <li> [sqlite3_mutex_held()] </li> 5790** <li> [sqlite3_mutex_notheld()] </li> 5791** </ul>)^ 5792** 5793** The only difference is that the public sqlite3_XXX functions enumerated 5794** above silently ignore any invocations that pass a NULL pointer instead 5795** of a valid mutex handle. The implementations of the methods defined 5796** by this structure are not required to handle this case, the results 5797** of passing a NULL pointer instead of a valid mutex handle are undefined 5798** (i.e. it is acceptable to provide an implementation that segfaults if 5799** it is passed a NULL pointer). 5800** 5801** The xMutexInit() method must be threadsafe. ^It must be harmless to 5802** invoke xMutexInit() multiple times within the same process and without 5803** intervening calls to xMutexEnd(). Second and subsequent calls to 5804** xMutexInit() must be no-ops. 5805** 5806** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 5807** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 5808** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 5809** memory allocation for a fast or recursive mutex. 5810** 5811** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 5812** called, but only if the prior call to xMutexInit returned SQLITE_OK. 5813** If xMutexInit fails in any way, it is expected to clean up after itself 5814** prior to returning. 5815*/ 5816typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 5817struct sqlite3_mutex_methods { 5818 int (*xMutexInit)(void); 5819 int (*xMutexEnd)(void); 5820 sqlite3_mutex *(*xMutexAlloc)(int); 5821 void (*xMutexFree)(sqlite3_mutex *); 5822 void (*xMutexEnter)(sqlite3_mutex *); 5823 int (*xMutexTry)(sqlite3_mutex *); 5824 void (*xMutexLeave)(sqlite3_mutex *); 5825 int (*xMutexHeld)(sqlite3_mutex *); 5826 int (*xMutexNotheld)(sqlite3_mutex *); 5827}; 5828 5829/* 5830** CAPI3REF: Mutex Verification Routines 5831** 5832** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 5833** are intended for use inside assert() statements. ^The SQLite core 5834** never uses these routines except inside an assert() and applications 5835** are advised to follow the lead of the core. ^The SQLite core only 5836** provides implementations for these routines when it is compiled 5837** with the SQLITE_DEBUG flag. ^External mutex implementations 5838** are only required to provide these routines if SQLITE_DEBUG is 5839** defined and if NDEBUG is not defined. 5840** 5841** ^These routines should return true if the mutex in their argument 5842** is held or not held, respectively, by the calling thread. 5843** 5844** ^The implementation is not required to provide versions of these 5845** routines that actually work. If the implementation does not provide working 5846** versions of these routines, it should at least provide stubs that always 5847** return true so that one does not get spurious assertion failures. 5848** 5849** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 5850** the routine should return 1. This seems counter-intuitive since 5851** clearly the mutex cannot be held if it does not exist. But 5852** the reason the mutex does not exist is because the build is not 5853** using mutexes. And we do not want the assert() containing the 5854** call to sqlite3_mutex_held() to fail, so a non-zero return is 5855** the appropriate thing to do. ^The sqlite3_mutex_notheld() 5856** interface should also return 1 when given a NULL pointer. 5857*/ 5858#ifndef NDEBUG 5859int sqlite3_mutex_held(sqlite3_mutex*); 5860int sqlite3_mutex_notheld(sqlite3_mutex*); 5861#endif 5862 5863/* 5864** CAPI3REF: Mutex Types 5865** 5866** The [sqlite3_mutex_alloc()] interface takes a single argument 5867** which is one of these integer constants. 5868** 5869** The set of static mutexes may change from one SQLite release to the 5870** next. Applications that override the built-in mutex logic must be 5871** prepared to accommodate additional static mutexes. 5872*/ 5873#define SQLITE_MUTEX_FAST 0 5874#define SQLITE_MUTEX_RECURSIVE 1 5875#define SQLITE_MUTEX_STATIC_MASTER 2 5876#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 5877#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 5878#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 5879#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 5880#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 5881#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 5882#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 5883 5884/* 5885** CAPI3REF: Retrieve the mutex for a database connection 5886** 5887** ^This interface returns a pointer the [sqlite3_mutex] object that 5888** serializes access to the [database connection] given in the argument 5889** when the [threading mode] is Serialized. 5890** ^If the [threading mode] is Single-thread or Multi-thread then this 5891** routine returns a NULL pointer. 5892*/ 5893sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 5894 5895/* 5896** CAPI3REF: Low-Level Control Of Database Files 5897** 5898** ^The [sqlite3_file_control()] interface makes a direct call to the 5899** xFileControl method for the [sqlite3_io_methods] object associated 5900** with a particular database identified by the second argument. ^The 5901** name of the database is "main" for the main database or "temp" for the 5902** TEMP database, or the name that appears after the AS keyword for 5903** databases that are added using the [ATTACH] SQL command. 5904** ^A NULL pointer can be used in place of "main" to refer to the 5905** main database file. 5906** ^The third and fourth parameters to this routine 5907** are passed directly through to the second and third parameters of 5908** the xFileControl method. ^The return value of the xFileControl 5909** method becomes the return value of this routine. 5910** 5911** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 5912** a pointer to the underlying [sqlite3_file] object to be written into 5913** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 5914** case is a short-circuit path which does not actually invoke the 5915** underlying sqlite3_io_methods.xFileControl method. 5916** 5917** ^If the second parameter (zDbName) does not match the name of any 5918** open database file, then SQLITE_ERROR is returned. ^This error 5919** code is not remembered and will not be recalled by [sqlite3_errcode()] 5920** or [sqlite3_errmsg()]. The underlying xFileControl method might 5921** also return SQLITE_ERROR. There is no way to distinguish between 5922** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5923** xFileControl method. 5924** 5925** See also: [SQLITE_FCNTL_LOCKSTATE] 5926*/ 5927int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5928 5929/* 5930** CAPI3REF: Testing Interface 5931** 5932** ^The sqlite3_test_control() interface is used to read out internal 5933** state of SQLite and to inject faults into SQLite for testing 5934** purposes. ^The first parameter is an operation code that determines 5935** the number, meaning, and operation of all subsequent parameters. 5936** 5937** This interface is not for use by applications. It exists solely 5938** for verifying the correct operation of the SQLite library. Depending 5939** on how the SQLite library is compiled, this interface might not exist. 5940** 5941** The details of the operation codes, their meanings, the parameters 5942** they take, and what they do are all subject to change without notice. 5943** Unlike most of the SQLite API, this function is not guaranteed to 5944** operate consistently from one release to the next. 5945*/ 5946int sqlite3_test_control(int op, ...); 5947 5948/* 5949** CAPI3REF: Testing Interface Operation Codes 5950** 5951** These constants are the valid operation code parameters used 5952** as the first argument to [sqlite3_test_control()]. 5953** 5954** These parameters and their meanings are subject to change 5955** without notice. These values are for testing purposes only. 5956** Applications should not use any of these parameters or the 5957** [sqlite3_test_control()] interface. 5958*/ 5959#define SQLITE_TESTCTRL_FIRST 5 5960#define SQLITE_TESTCTRL_PRNG_SAVE 5 5961#define SQLITE_TESTCTRL_PRNG_RESTORE 6 5962#define SQLITE_TESTCTRL_PRNG_RESET 7 5963#define SQLITE_TESTCTRL_BITVEC_TEST 8 5964#define SQLITE_TESTCTRL_FAULT_INSTALL 9 5965#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5966#define SQLITE_TESTCTRL_PENDING_BYTE 11 5967#define SQLITE_TESTCTRL_ASSERT 12 5968#define SQLITE_TESTCTRL_ALWAYS 13 5969#define SQLITE_TESTCTRL_RESERVE 14 5970#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 5971#define SQLITE_TESTCTRL_ISKEYWORD 16 5972#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 5973#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 5974#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 5975#define SQLITE_TESTCTRL_LAST 19 5976 5977/* 5978** CAPI3REF: SQLite Runtime Status 5979** 5980** ^This interface is used to retrieve runtime status information 5981** about the performance of SQLite, and optionally to reset various 5982** highwater marks. ^The first argument is an integer code for 5983** the specific parameter to measure. ^(Recognized integer codes 5984** are of the form [status parameters | SQLITE_STATUS_...].)^ 5985** ^The current value of the parameter is returned into *pCurrent. 5986** ^The highest recorded value is returned in *pHighwater. ^If the 5987** resetFlag is true, then the highest record value is reset after 5988** *pHighwater is written. ^(Some parameters do not record the highest 5989** value. For those parameters 5990** nothing is written into *pHighwater and the resetFlag is ignored.)^ 5991** ^(Other parameters record only the highwater mark and not the current 5992** value. For these latter parameters nothing is written into *pCurrent.)^ 5993** 5994** ^The sqlite3_status() routine returns SQLITE_OK on success and a 5995** non-zero [error code] on failure. 5996** 5997** This routine is threadsafe but is not atomic. This routine can be 5998** called while other threads are running the same or different SQLite 5999** interfaces. However the values returned in *pCurrent and 6000** *pHighwater reflect the status of SQLite at different points in time 6001** and it is possible that another thread might change the parameter 6002** in between the times when *pCurrent and *pHighwater are written. 6003** 6004** See also: [sqlite3_db_status()] 6005*/ 6006int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 6007 6008 6009/* 6010** CAPI3REF: Status Parameters 6011** KEYWORDS: {status parameters} 6012** 6013** These integer constants designate various run-time status parameters 6014** that can be returned by [sqlite3_status()]. 6015** 6016** <dl> 6017** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 6018** <dd>This parameter is the current amount of memory checked out 6019** using [sqlite3_malloc()], either directly or indirectly. The 6020** figure includes calls made to [sqlite3_malloc()] by the application 6021** and internal memory usage by the SQLite library. Scratch memory 6022** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 6023** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 6024** this parameter. The amount returned is the sum of the allocation 6025** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 6026** 6027** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 6028** <dd>This parameter records the largest memory allocation request 6029** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 6030** internal equivalents). Only the value returned in the 6031** *pHighwater parameter to [sqlite3_status()] is of interest. 6032** The value written into the *pCurrent parameter is undefined.</dd>)^ 6033** 6034** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 6035** <dd>This parameter records the number of separate memory allocations 6036** currently checked out.</dd>)^ 6037** 6038** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 6039** <dd>This parameter returns the number of pages used out of the 6040** [pagecache memory allocator] that was configured using 6041** [SQLITE_CONFIG_PAGECACHE]. The 6042** value returned is in pages, not in bytes.</dd>)^ 6043** 6044** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 6045** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 6046** <dd>This parameter returns the number of bytes of page cache 6047** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 6048** buffer and where forced to overflow to [sqlite3_malloc()]. The 6049** returned value includes allocations that overflowed because they 6050** where too large (they were larger than the "sz" parameter to 6051** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 6052** no space was left in the page cache.</dd>)^ 6053** 6054** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 6055** <dd>This parameter records the largest memory allocation request 6056** handed to [pagecache memory allocator]. Only the value returned in the 6057** *pHighwater parameter to [sqlite3_status()] is of interest. 6058** The value written into the *pCurrent parameter is undefined.</dd>)^ 6059** 6060** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 6061** <dd>This parameter returns the number of allocations used out of the 6062** [scratch memory allocator] configured using 6063** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 6064** in bytes. Since a single thread may only have one scratch allocation 6065** outstanding at time, this parameter also reports the number of threads 6066** using scratch memory at the same time.</dd>)^ 6067** 6068** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 6069** <dd>This parameter returns the number of bytes of scratch memory 6070** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 6071** buffer and where forced to overflow to [sqlite3_malloc()]. The values 6072** returned include overflows because the requested allocation was too 6073** larger (that is, because the requested allocation was larger than the 6074** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 6075** slots were available. 6076** </dd>)^ 6077** 6078** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 6079** <dd>This parameter records the largest memory allocation request 6080** handed to [scratch memory allocator]. Only the value returned in the 6081** *pHighwater parameter to [sqlite3_status()] is of interest. 6082** The value written into the *pCurrent parameter is undefined.</dd>)^ 6083** 6084** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 6085** <dd>This parameter records the deepest parser stack. It is only 6086** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 6087** </dl> 6088** 6089** New status parameters may be added from time to time. 6090*/ 6091#define SQLITE_STATUS_MEMORY_USED 0 6092#define SQLITE_STATUS_PAGECACHE_USED 1 6093#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 6094#define SQLITE_STATUS_SCRATCH_USED 3 6095#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 6096#define SQLITE_STATUS_MALLOC_SIZE 5 6097#define SQLITE_STATUS_PARSER_STACK 6 6098#define SQLITE_STATUS_PAGECACHE_SIZE 7 6099#define SQLITE_STATUS_SCRATCH_SIZE 8 6100#define SQLITE_STATUS_MALLOC_COUNT 9 6101 6102/* 6103** CAPI3REF: Database Connection Status 6104** 6105** ^This interface is used to retrieve runtime status information 6106** about a single [database connection]. ^The first argument is the 6107** database connection object to be interrogated. ^The second argument 6108** is an integer constant, taken from the set of 6109** [SQLITE_DBSTATUS options], that 6110** determines the parameter to interrogate. The set of 6111** [SQLITE_DBSTATUS options] is likely 6112** to grow in future releases of SQLite. 6113** 6114** ^The current value of the requested parameter is written into *pCur 6115** and the highest instantaneous value is written into *pHiwtr. ^If 6116** the resetFlg is true, then the highest instantaneous value is 6117** reset back down to the current value. 6118** 6119** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 6120** non-zero [error code] on failure. 6121** 6122** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 6123*/ 6124int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 6125 6126/* 6127** CAPI3REF: Status Parameters for database connections 6128** KEYWORDS: {SQLITE_DBSTATUS options} 6129** 6130** These constants are the available integer "verbs" that can be passed as 6131** the second argument to the [sqlite3_db_status()] interface. 6132** 6133** New verbs may be added in future releases of SQLite. Existing verbs 6134** might be discontinued. Applications should check the return code from 6135** [sqlite3_db_status()] to make sure that the call worked. 6136** The [sqlite3_db_status()] interface will return a non-zero error code 6137** if a discontinued or unsupported verb is invoked. 6138** 6139** <dl> 6140** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 6141** <dd>This parameter returns the number of lookaside memory slots currently 6142** checked out.</dd>)^ 6143** 6144** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 6145** <dd>This parameter returns the number malloc attempts that were 6146** satisfied using lookaside memory. Only the high-water value is meaningful; 6147** the current value is always zero.)^ 6148** 6149** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 6150** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 6151** <dd>This parameter returns the number malloc attempts that might have 6152** been satisfied using lookaside memory but failed due to the amount of 6153** memory requested being larger than the lookaside slot size. 6154** Only the high-water value is meaningful; 6155** the current value is always zero.)^ 6156** 6157** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 6158** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 6159** <dd>This parameter returns the number malloc attempts that might have 6160** been satisfied using lookaside memory but failed due to all lookaside 6161** memory already being in use. 6162** Only the high-water value is meaningful; 6163** the current value is always zero.)^ 6164** 6165** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 6166** <dd>This parameter returns the approximate number of of bytes of heap 6167** memory used by all pager caches associated with the database connection.)^ 6168** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 6169** 6170** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 6171** <dd>This parameter returns the approximate number of of bytes of heap 6172** memory used to store the schema for all databases associated 6173** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 6174** ^The full amount of memory used by the schemas is reported, even if the 6175** schema memory is shared with other database connections due to 6176** [shared cache mode] being enabled. 6177** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 6178** 6179** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 6180** <dd>This parameter returns the approximate number of of bytes of heap 6181** and lookaside memory used by all prepared statements associated with 6182** the database connection.)^ 6183** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 6184** </dd> 6185** 6186** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 6187** <dd>This parameter returns the number of pager cache hits that have 6188** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 6189** is always 0. 6190** </dd> 6191** 6192** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6193** <dd>This parameter returns the number of pager cache misses that have 6194** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6195** is always 0. 6196** </dd> 6197** 6198** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 6199** <dd>This parameter returns the number of dirty cache entries that have 6200** been written to disk. Specifically, the number of pages written to the 6201** wal file in wal mode databases, or the number of pages written to the 6202** database file in rollback mode databases. Any pages written as part of 6203** transaction rollback or database recovery operations are not included. 6204** If an IO or other error occurs while writing a page to disk, the effect 6205** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 6206** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 6207** </dd> 6208** </dl> 6209*/ 6210#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6211#define SQLITE_DBSTATUS_CACHE_USED 1 6212#define SQLITE_DBSTATUS_SCHEMA_USED 2 6213#define SQLITE_DBSTATUS_STMT_USED 3 6214#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6215#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6216#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 6217#define SQLITE_DBSTATUS_CACHE_HIT 7 6218#define SQLITE_DBSTATUS_CACHE_MISS 8 6219#define SQLITE_DBSTATUS_CACHE_WRITE 9 6220#define SQLITE_DBSTATUS_MAX 9 /* Largest defined DBSTATUS */ 6221 6222 6223/* 6224** CAPI3REF: Prepared Statement Status 6225** 6226** ^(Each prepared statement maintains various 6227** [SQLITE_STMTSTATUS counters] that measure the number 6228** of times it has performed specific operations.)^ These counters can 6229** be used to monitor the performance characteristics of the prepared 6230** statements. For example, if the number of table steps greatly exceeds 6231** the number of table searches or result rows, that would tend to indicate 6232** that the prepared statement is using a full table scan rather than 6233** an index. 6234** 6235** ^(This interface is used to retrieve and reset counter values from 6236** a [prepared statement]. The first argument is the prepared statement 6237** object to be interrogated. The second argument 6238** is an integer code for a specific [SQLITE_STMTSTATUS counter] 6239** to be interrogated.)^ 6240** ^The current value of the requested counter is returned. 6241** ^If the resetFlg is true, then the counter is reset to zero after this 6242** interface call returns. 6243** 6244** See also: [sqlite3_status()] and [sqlite3_db_status()]. 6245*/ 6246int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 6247 6248/* 6249** CAPI3REF: Status Parameters for prepared statements 6250** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 6251** 6252** These preprocessor macros define integer codes that name counter 6253** values associated with the [sqlite3_stmt_status()] interface. 6254** The meanings of the various counters are as follows: 6255** 6256** <dl> 6257** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 6258** <dd>^This is the number of times that SQLite has stepped forward in 6259** a table as part of a full table scan. Large numbers for this counter 6260** may indicate opportunities for performance improvement through 6261** careful use of indices.</dd> 6262** 6263** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 6264** <dd>^This is the number of sort operations that have occurred. 6265** A non-zero value in this counter may indicate an opportunity to 6266** improvement performance through careful use of indices.</dd> 6267** 6268** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 6269** <dd>^This is the number of rows inserted into transient indices that 6270** were created automatically in order to help joins run faster. 6271** A non-zero value in this counter may indicate an opportunity to 6272** improvement performance by adding permanent indices that do not 6273** need to be reinitialized each time the statement is run.</dd> 6274** </dl> 6275*/ 6276#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 6277#define SQLITE_STMTSTATUS_SORT 2 6278#define SQLITE_STMTSTATUS_AUTOINDEX 3 6279 6280/* 6281** CAPI3REF: Custom Page Cache Object 6282** 6283** The sqlite3_pcache type is opaque. It is implemented by 6284** the pluggable module. The SQLite core has no knowledge of 6285** its size or internal structure and never deals with the 6286** sqlite3_pcache object except by holding and passing pointers 6287** to the object. 6288** 6289** See [sqlite3_pcache_methods2] for additional information. 6290*/ 6291typedef struct sqlite3_pcache sqlite3_pcache; 6292 6293/* 6294** CAPI3REF: Custom Page Cache Object 6295** 6296** The sqlite3_pcache_page object represents a single page in the 6297** page cache. The page cache will allocate instances of this 6298** object. Various methods of the page cache use pointers to instances 6299** of this object as parameters or as their return value. 6300** 6301** See [sqlite3_pcache_methods2] for additional information. 6302*/ 6303typedef struct sqlite3_pcache_page sqlite3_pcache_page; 6304struct sqlite3_pcache_page { 6305 void *pBuf; /* The content of the page */ 6306 void *pExtra; /* Extra information associated with the page */ 6307}; 6308 6309/* 6310** CAPI3REF: Application Defined Page Cache. 6311** KEYWORDS: {page cache} 6312** 6313** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 6314** register an alternative page cache implementation by passing in an 6315** instance of the sqlite3_pcache_methods2 structure.)^ 6316** In many applications, most of the heap memory allocated by 6317** SQLite is used for the page cache. 6318** By implementing a 6319** custom page cache using this API, an application can better control 6320** the amount of memory consumed by SQLite, the way in which 6321** that memory is allocated and released, and the policies used to 6322** determine exactly which parts of a database file are cached and for 6323** how long. 6324** 6325** The alternative page cache mechanism is an 6326** extreme measure that is only needed by the most demanding applications. 6327** The built-in page cache is recommended for most uses. 6328** 6329** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 6330** internal buffer by SQLite within the call to [sqlite3_config]. Hence 6331** the application may discard the parameter after the call to 6332** [sqlite3_config()] returns.)^ 6333** 6334** [[the xInit() page cache method]] 6335** ^(The xInit() method is called once for each effective 6336** call to [sqlite3_initialize()])^ 6337** (usually only once during the lifetime of the process). ^(The xInit() 6338** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 6339** The intent of the xInit() method is to set up global data structures 6340** required by the custom page cache implementation. 6341** ^(If the xInit() method is NULL, then the 6342** built-in default page cache is used instead of the application defined 6343** page cache.)^ 6344** 6345** [[the xShutdown() page cache method]] 6346** ^The xShutdown() method is called by [sqlite3_shutdown()]. 6347** It can be used to clean up 6348** any outstanding resources before process shutdown, if required. 6349** ^The xShutdown() method may be NULL. 6350** 6351** ^SQLite automatically serializes calls to the xInit method, 6352** so the xInit method need not be threadsafe. ^The 6353** xShutdown method is only called from [sqlite3_shutdown()] so it does 6354** not need to be threadsafe either. All other methods must be threadsafe 6355** in multithreaded applications. 6356** 6357** ^SQLite will never invoke xInit() more than once without an intervening 6358** call to xShutdown(). 6359** 6360** [[the xCreate() page cache methods]] 6361** ^SQLite invokes the xCreate() method to construct a new cache instance. 6362** SQLite will typically create one cache instance for each open database file, 6363** though this is not guaranteed. ^The 6364** first parameter, szPage, is the size in bytes of the pages that must 6365** be allocated by the cache. ^szPage will always a power of two. ^The 6366** second parameter szExtra is a number of bytes of extra storage 6367** associated with each page cache entry. ^The szExtra parameter will 6368** a number less than 250. SQLite will use the 6369** extra szExtra bytes on each page to store metadata about the underlying 6370** database page on disk. The value passed into szExtra depends 6371** on the SQLite version, the target platform, and how SQLite was compiled. 6372** ^The third argument to xCreate(), bPurgeable, is true if the cache being 6373** created will be used to cache database pages of a file stored on disk, or 6374** false if it is used for an in-memory database. The cache implementation 6375** does not have to do anything special based with the value of bPurgeable; 6376** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 6377** never invoke xUnpin() except to deliberately delete a page. 6378** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 6379** false will always have the "discard" flag set to true. 6380** ^Hence, a cache created with bPurgeable false will 6381** never contain any unpinned pages. 6382** 6383** [[the xCachesize() page cache method]] 6384** ^(The xCachesize() method may be called at any time by SQLite to set the 6385** suggested maximum cache-size (number of pages stored by) the cache 6386** instance passed as the first argument. This is the value configured using 6387** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 6388** parameter, the implementation is not required to do anything with this 6389** value; it is advisory only. 6390** 6391** [[the xPagecount() page cache methods]] 6392** The xPagecount() method must return the number of pages currently 6393** stored in the cache, both pinned and unpinned. 6394** 6395** [[the xFetch() page cache methods]] 6396** The xFetch() method locates a page in the cache and returns a pointer to 6397** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 6398** The pBuf element of the returned sqlite3_pcache_page object will be a 6399** pointer to a buffer of szPage bytes used to store the content of a 6400** single database page. The pExtra element of sqlite3_pcache_page will be 6401** a pointer to the szExtra bytes of extra storage that SQLite has requested 6402** for each entry in the page cache. 6403** 6404** The page to be fetched is determined by the key. ^The minimum key value 6405** is 1. After it has been retrieved using xFetch, the page is considered 6406** to be "pinned". 6407** 6408** If the requested page is already in the page cache, then the page cache 6409** implementation must return a pointer to the page buffer with its content 6410** intact. If the requested page is not already in the cache, then the 6411** cache implementation should use the value of the createFlag 6412** parameter to help it determined what action to take: 6413** 6414** <table border=1 width=85% align=center> 6415** <tr><th> createFlag <th> Behavior when page is not already in cache 6416** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6417** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6418** Otherwise return NULL. 6419** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6420** NULL if allocating a new page is effectively impossible. 6421** </table> 6422** 6423** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6424** will only use a createFlag of 2 after a prior call with a createFlag of 1 6425** failed.)^ In between the to xFetch() calls, SQLite may 6426** attempt to unpin one or more cache pages by spilling the content of 6427** pinned pages to disk and synching the operating system disk cache. 6428** 6429** [[the xUnpin() page cache method]] 6430** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6431** as its second argument. If the third parameter, discard, is non-zero, 6432** then the page must be evicted from the cache. 6433** ^If the discard parameter is 6434** zero, then the page may be discarded or retained at the discretion of 6435** page cache implementation. ^The page cache implementation 6436** may choose to evict unpinned pages at any time. 6437** 6438** The cache must not perform any reference counting. A single 6439** call to xUnpin() unpins the page regardless of the number of prior calls 6440** to xFetch(). 6441** 6442** [[the xRekey() page cache methods]] 6443** The xRekey() method is used to change the key value associated with the 6444** page passed as the second argument. If the cache 6445** previously contains an entry associated with newKey, it must be 6446** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6447** to be pinned. 6448** 6449** When SQLite calls the xTruncate() method, the cache must discard all 6450** existing cache entries with page numbers (keys) greater than or equal 6451** to the value of the iLimit parameter passed to xTruncate(). If any 6452** of these pages are pinned, they are implicitly unpinned, meaning that 6453** they can be safely discarded. 6454** 6455** [[the xDestroy() page cache method]] 6456** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6457** All resources associated with the specified cache should be freed. ^After 6458** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6459** handle invalid, and will not use it with any other sqlite3_pcache_methods2 6460** functions. 6461** 6462** [[the xShrink() page cache method]] 6463** ^SQLite invokes the xShrink() method when it wants the page cache to 6464** free up as much of heap memory as possible. The page cache implementation 6465** is not obligated to free any memory, but well-behaved implementations should 6466** do their best. 6467*/ 6468typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 6469struct sqlite3_pcache_methods2 { 6470 int iVersion; 6471 void *pArg; 6472 int (*xInit)(void*); 6473 void (*xShutdown)(void*); 6474 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 6475 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6476 int (*xPagecount)(sqlite3_pcache*); 6477 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6478 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 6479 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 6480 unsigned oldKey, unsigned newKey); 6481 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6482 void (*xDestroy)(sqlite3_pcache*); 6483 void (*xShrink)(sqlite3_pcache*); 6484}; 6485 6486/* 6487** This is the obsolete pcache_methods object that has now been replaced 6488** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 6489** retained in the header file for backwards compatibility only. 6490*/ 6491typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 6492struct sqlite3_pcache_methods { 6493 void *pArg; 6494 int (*xInit)(void*); 6495 void (*xShutdown)(void*); 6496 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 6497 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6498 int (*xPagecount)(sqlite3_pcache*); 6499 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6500 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 6501 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 6502 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6503 void (*xDestroy)(sqlite3_pcache*); 6504}; 6505 6506 6507/* 6508** CAPI3REF: Online Backup Object 6509** 6510** The sqlite3_backup object records state information about an ongoing 6511** online backup operation. ^The sqlite3_backup object is created by 6512** a call to [sqlite3_backup_init()] and is destroyed by a call to 6513** [sqlite3_backup_finish()]. 6514** 6515** See Also: [Using the SQLite Online Backup API] 6516*/ 6517typedef struct sqlite3_backup sqlite3_backup; 6518 6519/* 6520** CAPI3REF: Online Backup API. 6521** 6522** The backup API copies the content of one database into another. 6523** It is useful either for creating backups of databases or 6524** for copying in-memory databases to or from persistent files. 6525** 6526** See Also: [Using the SQLite Online Backup API] 6527** 6528** ^SQLite holds a write transaction open on the destination database file 6529** for the duration of the backup operation. 6530** ^The source database is read-locked only while it is being read; 6531** it is not locked continuously for the entire backup operation. 6532** ^Thus, the backup may be performed on a live source database without 6533** preventing other database connections from 6534** reading or writing to the source database while the backup is underway. 6535** 6536** ^(To perform a backup operation: 6537** <ol> 6538** <li><b>sqlite3_backup_init()</b> is called once to initialize the 6539** backup, 6540** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 6541** the data between the two databases, and finally 6542** <li><b>sqlite3_backup_finish()</b> is called to release all resources 6543** associated with the backup operation. 6544** </ol>)^ 6545** There should be exactly one call to sqlite3_backup_finish() for each 6546** successful call to sqlite3_backup_init(). 6547** 6548** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 6549** 6550** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 6551** [database connection] associated with the destination database 6552** and the database name, respectively. 6553** ^The database name is "main" for the main database, "temp" for the 6554** temporary database, or the name specified after the AS keyword in 6555** an [ATTACH] statement for an attached database. 6556** ^The S and M arguments passed to 6557** sqlite3_backup_init(D,N,S,M) identify the [database connection] 6558** and database name of the source database, respectively. 6559** ^The source and destination [database connections] (parameters S and D) 6560** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 6561** an error. 6562** 6563** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 6564** returned and an error code and error message are stored in the 6565** destination [database connection] D. 6566** ^The error code and message for the failed call to sqlite3_backup_init() 6567** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 6568** [sqlite3_errmsg16()] functions. 6569** ^A successful call to sqlite3_backup_init() returns a pointer to an 6570** [sqlite3_backup] object. 6571** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 6572** sqlite3_backup_finish() functions to perform the specified backup 6573** operation. 6574** 6575** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 6576** 6577** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 6578** the source and destination databases specified by [sqlite3_backup] object B. 6579** ^If N is negative, all remaining source pages are copied. 6580** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 6581** are still more pages to be copied, then the function returns [SQLITE_OK]. 6582** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 6583** from source to destination, then it returns [SQLITE_DONE]. 6584** ^If an error occurs while running sqlite3_backup_step(B,N), 6585** then an [error code] is returned. ^As well as [SQLITE_OK] and 6586** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 6587** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 6588** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 6589** 6590** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 6591** <ol> 6592** <li> the destination database was opened read-only, or 6593** <li> the destination database is using write-ahead-log journaling 6594** and the destination and source page sizes differ, or 6595** <li> the destination database is an in-memory database and the 6596** destination and source page sizes differ. 6597** </ol>)^ 6598** 6599** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 6600** the [sqlite3_busy_handler | busy-handler function] 6601** is invoked (if one is specified). ^If the 6602** busy-handler returns non-zero before the lock is available, then 6603** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 6604** sqlite3_backup_step() can be retried later. ^If the source 6605** [database connection] 6606** is being used to write to the source database when sqlite3_backup_step() 6607** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 6608** case the call to sqlite3_backup_step() can be retried later on. ^(If 6609** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 6610** [SQLITE_READONLY] is returned, then 6611** there is no point in retrying the call to sqlite3_backup_step(). These 6612** errors are considered fatal.)^ The application must accept 6613** that the backup operation has failed and pass the backup operation handle 6614** to the sqlite3_backup_finish() to release associated resources. 6615** 6616** ^The first call to sqlite3_backup_step() obtains an exclusive lock 6617** on the destination file. ^The exclusive lock is not released until either 6618** sqlite3_backup_finish() is called or the backup operation is complete 6619** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 6620** sqlite3_backup_step() obtains a [shared lock] on the source database that 6621** lasts for the duration of the sqlite3_backup_step() call. 6622** ^Because the source database is not locked between calls to 6623** sqlite3_backup_step(), the source database may be modified mid-way 6624** through the backup process. ^If the source database is modified by an 6625** external process or via a database connection other than the one being 6626** used by the backup operation, then the backup will be automatically 6627** restarted by the next call to sqlite3_backup_step(). ^If the source 6628** database is modified by the using the same database connection as is used 6629** by the backup operation, then the backup database is automatically 6630** updated at the same time. 6631** 6632** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 6633** 6634** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 6635** application wishes to abandon the backup operation, the application 6636** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 6637** ^The sqlite3_backup_finish() interfaces releases all 6638** resources associated with the [sqlite3_backup] object. 6639** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 6640** active write-transaction on the destination database is rolled back. 6641** The [sqlite3_backup] object is invalid 6642** and may not be used following a call to sqlite3_backup_finish(). 6643** 6644** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 6645** sqlite3_backup_step() errors occurred, regardless or whether or not 6646** sqlite3_backup_step() completed. 6647** ^If an out-of-memory condition or IO error occurred during any prior 6648** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 6649** sqlite3_backup_finish() returns the corresponding [error code]. 6650** 6651** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 6652** is not a permanent error and does not affect the return value of 6653** sqlite3_backup_finish(). 6654** 6655** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]] 6656** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 6657** 6658** ^Each call to sqlite3_backup_step() sets two values inside 6659** the [sqlite3_backup] object: the number of pages still to be backed 6660** up and the total number of pages in the source database file. 6661** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 6662** retrieve these two values, respectively. 6663** 6664** ^The values returned by these functions are only updated by 6665** sqlite3_backup_step(). ^If the source database is modified during a backup 6666** operation, then the values are not updated to account for any extra 6667** pages that need to be updated or the size of the source database file 6668** changing. 6669** 6670** <b>Concurrent Usage of Database Handles</b> 6671** 6672** ^The source [database connection] may be used by the application for other 6673** purposes while a backup operation is underway or being initialized. 6674** ^If SQLite is compiled and configured to support threadsafe database 6675** connections, then the source database connection may be used concurrently 6676** from within other threads. 6677** 6678** However, the application must guarantee that the destination 6679** [database connection] is not passed to any other API (by any thread) after 6680** sqlite3_backup_init() is called and before the corresponding call to 6681** sqlite3_backup_finish(). SQLite does not currently check to see 6682** if the application incorrectly accesses the destination [database connection] 6683** and so no error code is reported, but the operations may malfunction 6684** nevertheless. Use of the destination database connection while a 6685** backup is in progress might also also cause a mutex deadlock. 6686** 6687** If running in [shared cache mode], the application must 6688** guarantee that the shared cache used by the destination database 6689** is not accessed while the backup is running. In practice this means 6690** that the application must guarantee that the disk file being 6691** backed up to is not accessed by any connection within the process, 6692** not just the specific connection that was passed to sqlite3_backup_init(). 6693** 6694** The [sqlite3_backup] object itself is partially threadsafe. Multiple 6695** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 6696** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 6697** APIs are not strictly speaking threadsafe. If they are invoked at the 6698** same time as another thread is invoking sqlite3_backup_step() it is 6699** possible that they return invalid values. 6700*/ 6701sqlite3_backup *sqlite3_backup_init( 6702 sqlite3 *pDest, /* Destination database handle */ 6703 const char *zDestName, /* Destination database name */ 6704 sqlite3 *pSource, /* Source database handle */ 6705 const char *zSourceName /* Source database name */ 6706); 6707int sqlite3_backup_step(sqlite3_backup *p, int nPage); 6708int sqlite3_backup_finish(sqlite3_backup *p); 6709int sqlite3_backup_remaining(sqlite3_backup *p); 6710int sqlite3_backup_pagecount(sqlite3_backup *p); 6711 6712/* 6713** CAPI3REF: Unlock Notification 6714** 6715** ^When running in shared-cache mode, a database operation may fail with 6716** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 6717** individual tables within the shared-cache cannot be obtained. See 6718** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 6719** ^This API may be used to register a callback that SQLite will invoke 6720** when the connection currently holding the required lock relinquishes it. 6721** ^This API is only available if the library was compiled with the 6722** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 6723** 6724** See Also: [Using the SQLite Unlock Notification Feature]. 6725** 6726** ^Shared-cache locks are released when a database connection concludes 6727** its current transaction, either by committing it or rolling it back. 6728** 6729** ^When a connection (known as the blocked connection) fails to obtain a 6730** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 6731** identity of the database connection (the blocking connection) that 6732** has locked the required resource is stored internally. ^After an 6733** application receives an SQLITE_LOCKED error, it may call the 6734** sqlite3_unlock_notify() method with the blocked connection handle as 6735** the first argument to register for a callback that will be invoked 6736** when the blocking connections current transaction is concluded. ^The 6737** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 6738** call that concludes the blocking connections transaction. 6739** 6740** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 6741** there is a chance that the blocking connection will have already 6742** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 6743** If this happens, then the specified callback is invoked immediately, 6744** from within the call to sqlite3_unlock_notify().)^ 6745** 6746** ^If the blocked connection is attempting to obtain a write-lock on a 6747** shared-cache table, and more than one other connection currently holds 6748** a read-lock on the same table, then SQLite arbitrarily selects one of 6749** the other connections to use as the blocking connection. 6750** 6751** ^(There may be at most one unlock-notify callback registered by a 6752** blocked connection. If sqlite3_unlock_notify() is called when the 6753** blocked connection already has a registered unlock-notify callback, 6754** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 6755** called with a NULL pointer as its second argument, then any existing 6756** unlock-notify callback is canceled. ^The blocked connections 6757** unlock-notify callback may also be canceled by closing the blocked 6758** connection using [sqlite3_close()]. 6759** 6760** The unlock-notify callback is not reentrant. If an application invokes 6761** any sqlite3_xxx API functions from within an unlock-notify callback, a 6762** crash or deadlock may be the result. 6763** 6764** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 6765** returns SQLITE_OK. 6766** 6767** <b>Callback Invocation Details</b> 6768** 6769** When an unlock-notify callback is registered, the application provides a 6770** single void* pointer that is passed to the callback when it is invoked. 6771** However, the signature of the callback function allows SQLite to pass 6772** it an array of void* context pointers. The first argument passed to 6773** an unlock-notify callback is a pointer to an array of void* pointers, 6774** and the second is the number of entries in the array. 6775** 6776** When a blocking connections transaction is concluded, there may be 6777** more than one blocked connection that has registered for an unlock-notify 6778** callback. ^If two or more such blocked connections have specified the 6779** same callback function, then instead of invoking the callback function 6780** multiple times, it is invoked once with the set of void* context pointers 6781** specified by the blocked connections bundled together into an array. 6782** This gives the application an opportunity to prioritize any actions 6783** related to the set of unblocked database connections. 6784** 6785** <b>Deadlock Detection</b> 6786** 6787** Assuming that after registering for an unlock-notify callback a 6788** database waits for the callback to be issued before taking any further 6789** action (a reasonable assumption), then using this API may cause the 6790** application to deadlock. For example, if connection X is waiting for 6791** connection Y's transaction to be concluded, and similarly connection 6792** Y is waiting on connection X's transaction, then neither connection 6793** will proceed and the system may remain deadlocked indefinitely. 6794** 6795** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 6796** detection. ^If a given call to sqlite3_unlock_notify() would put the 6797** system in a deadlocked state, then SQLITE_LOCKED is returned and no 6798** unlock-notify callback is registered. The system is said to be in 6799** a deadlocked state if connection A has registered for an unlock-notify 6800** callback on the conclusion of connection B's transaction, and connection 6801** B has itself registered for an unlock-notify callback when connection 6802** A's transaction is concluded. ^Indirect deadlock is also detected, so 6803** the system is also considered to be deadlocked if connection B has 6804** registered for an unlock-notify callback on the conclusion of connection 6805** C's transaction, where connection C is waiting on connection A. ^Any 6806** number of levels of indirection are allowed. 6807** 6808** <b>The "DROP TABLE" Exception</b> 6809** 6810** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 6811** always appropriate to call sqlite3_unlock_notify(). There is however, 6812** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 6813** SQLite checks if there are any currently executing SELECT statements 6814** that belong to the same connection. If there are, SQLITE_LOCKED is 6815** returned. In this case there is no "blocking connection", so invoking 6816** sqlite3_unlock_notify() results in the unlock-notify callback being 6817** invoked immediately. If the application then re-attempts the "DROP TABLE" 6818** or "DROP INDEX" query, an infinite loop might be the result. 6819** 6820** One way around this problem is to check the extended error code returned 6821** by an sqlite3_step() call. ^(If there is a blocking connection, then the 6822** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 6823** the special "DROP TABLE/INDEX" case, the extended error code is just 6824** SQLITE_LOCKED.)^ 6825*/ 6826int sqlite3_unlock_notify( 6827 sqlite3 *pBlocked, /* Waiting connection */ 6828 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 6829 void *pNotifyArg /* Argument to pass to xNotify */ 6830); 6831 6832 6833/* 6834** CAPI3REF: String Comparison 6835** 6836** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 6837** and extensions to compare the contents of two buffers containing UTF-8 6838** strings in a case-independent fashion, using the same definition of "case 6839** independence" that SQLite uses internally when comparing identifiers. 6840*/ 6841int sqlite3_stricmp(const char *, const char *); 6842int sqlite3_strnicmp(const char *, const char *, int); 6843 6844/* 6845** CAPI3REF: String Globbing 6846* 6847** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches 6848** the glob pattern P, and it returns non-zero if string X does not match 6849** the glob pattern P. ^The definition of glob pattern matching used in 6850** [sqlite3_strglob(P,X) is the same as for the "X GLOB P" operator in the 6851** SQL dialect used by SQLite. ^The sqlite3_strglob(P,X) function is case 6852** sensitive. 6853** 6854** Note that this routine returns zero on a match and non-zero if the strings 6855** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 6856*/ 6857int sqlite3_strglob(const char *zGlob, const char *zStr); 6858 6859/* 6860** CAPI3REF: Error Logging Interface 6861** 6862** ^The [sqlite3_log()] interface writes a message into the error log 6863** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 6864** ^If logging is enabled, the zFormat string and subsequent arguments are 6865** used with [sqlite3_snprintf()] to generate the final output string. 6866** 6867** The sqlite3_log() interface is intended for use by extensions such as 6868** virtual tables, collating functions, and SQL functions. While there is 6869** nothing to prevent an application from calling sqlite3_log(), doing so 6870** is considered bad form. 6871** 6872** The zFormat string must not be NULL. 6873** 6874** To avoid deadlocks and other threading problems, the sqlite3_log() routine 6875** will not use dynamically allocated memory. The log message is stored in 6876** a fixed-length buffer on the stack. If the log message is longer than 6877** a few hundred characters, it will be truncated to the length of the 6878** buffer. 6879*/ 6880void sqlite3_log(int iErrCode, const char *zFormat, ...); 6881 6882/* 6883** CAPI3REF: Write-Ahead Log Commit Hook 6884** 6885** ^The [sqlite3_wal_hook()] function is used to register a callback that 6886** will be invoked each time a database connection commits data to a 6887** [write-ahead log] (i.e. whenever a transaction is committed in 6888** [journal_mode | journal_mode=WAL mode]). 6889** 6890** ^The callback is invoked by SQLite after the commit has taken place and 6891** the associated write-lock on the database released, so the implementation 6892** may read, write or [checkpoint] the database as required. 6893** 6894** ^The first parameter passed to the callback function when it is invoked 6895** is a copy of the third parameter passed to sqlite3_wal_hook() when 6896** registering the callback. ^The second is a copy of the database handle. 6897** ^The third parameter is the name of the database that was written to - 6898** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 6899** is the number of pages currently in the write-ahead log file, 6900** including those that were just committed. 6901** 6902** The callback function should normally return [SQLITE_OK]. ^If an error 6903** code is returned, that error will propagate back up through the 6904** SQLite code base to cause the statement that provoked the callback 6905** to report an error, though the commit will have still occurred. If the 6906** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 6907** that does not correspond to any valid SQLite error code, the results 6908** are undefined. 6909** 6910** A single database handle may have at most a single write-ahead log callback 6911** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 6912** previously registered write-ahead log callback. ^Note that the 6913** [sqlite3_wal_autocheckpoint()] interface and the 6914** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 6915** those overwrite any prior [sqlite3_wal_hook()] settings. 6916*/ 6917void *sqlite3_wal_hook( 6918 sqlite3*, 6919 int(*)(void *,sqlite3*,const char*,int), 6920 void* 6921); 6922 6923/* 6924** CAPI3REF: Configure an auto-checkpoint 6925** 6926** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 6927** [sqlite3_wal_hook()] that causes any database on [database connection] D 6928** to automatically [checkpoint] 6929** after committing a transaction if there are N or 6930** more frames in the [write-ahead log] file. ^Passing zero or 6931** a negative value as the nFrame parameter disables automatic 6932** checkpoints entirely. 6933** 6934** ^The callback registered by this function replaces any existing callback 6935** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 6936** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 6937** configured by this function. 6938** 6939** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 6940** from SQL. 6941** 6942** ^Every new [database connection] defaults to having the auto-checkpoint 6943** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 6944** pages. The use of this interface 6945** is only necessary if the default setting is found to be suboptimal 6946** for a particular application. 6947*/ 6948int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 6949 6950/* 6951** CAPI3REF: Checkpoint a database 6952** 6953** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 6954** on [database connection] D to be [checkpointed]. ^If X is NULL or an 6955** empty string, then a checkpoint is run on all databases of 6956** connection D. ^If the database connection D is not in 6957** [WAL | write-ahead log mode] then this interface is a harmless no-op. 6958** 6959** ^The [wal_checkpoint pragma] can be used to invoke this interface 6960** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 6961** [wal_autocheckpoint pragma] can be used to cause this interface to be 6962** run whenever the WAL reaches a certain size threshold. 6963** 6964** See also: [sqlite3_wal_checkpoint_v2()] 6965*/ 6966int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 6967 6968/* 6969** CAPI3REF: Checkpoint a database 6970** 6971** Run a checkpoint operation on WAL database zDb attached to database 6972** handle db. The specific operation is determined by the value of the 6973** eMode parameter: 6974** 6975** <dl> 6976** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 6977** Checkpoint as many frames as possible without waiting for any database 6978** readers or writers to finish. Sync the db file if all frames in the log 6979** are checkpointed. This mode is the same as calling 6980** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked. 6981** 6982** <dt>SQLITE_CHECKPOINT_FULL<dd> 6983** This mode blocks (calls the busy-handler callback) until there is no 6984** database writer and all readers are reading from the most recent database 6985** snapshot. It then checkpoints all frames in the log file and syncs the 6986** database file. This call blocks database writers while it is running, 6987** but not database readers. 6988** 6989** <dt>SQLITE_CHECKPOINT_RESTART<dd> 6990** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after 6991** checkpointing the log file it blocks (calls the busy-handler callback) 6992** until all readers are reading from the database file only. This ensures 6993** that the next client to write to the database file restarts the log file 6994** from the beginning. This call blocks database writers while it is running, 6995** but not database readers. 6996** </dl> 6997** 6998** If pnLog is not NULL, then *pnLog is set to the total number of frames in 6999** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to 7000** the total number of checkpointed frames (including any that were already 7001** checkpointed when this function is called). *pnLog and *pnCkpt may be 7002** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK. 7003** If no values are available because of an error, they are both set to -1 7004** before returning to communicate this to the caller. 7005** 7006** All calls obtain an exclusive "checkpoint" lock on the database file. If 7007** any other process is running a checkpoint operation at the same time, the 7008** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a 7009** busy-handler configured, it will not be invoked in this case. 7010** 7011** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive 7012** "writer" lock on the database file. If the writer lock cannot be obtained 7013** immediately, and a busy-handler is configured, it is invoked and the writer 7014** lock retried until either the busy-handler returns 0 or the lock is 7015** successfully obtained. The busy-handler is also invoked while waiting for 7016** database readers as described above. If the busy-handler returns 0 before 7017** the writer lock is obtained or while waiting for database readers, the 7018** checkpoint operation proceeds from that point in the same way as 7019** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 7020** without blocking any further. SQLITE_BUSY is returned in this case. 7021** 7022** If parameter zDb is NULL or points to a zero length string, then the 7023** specified operation is attempted on all WAL databases. In this case the 7024** values written to output parameters *pnLog and *pnCkpt are undefined. If 7025** an SQLITE_BUSY error is encountered when processing one or more of the 7026** attached WAL databases, the operation is still attempted on any remaining 7027** attached databases and SQLITE_BUSY is returned to the caller. If any other 7028** error occurs while processing an attached database, processing is abandoned 7029** and the error code returned to the caller immediately. If no error 7030** (SQLITE_BUSY or otherwise) is encountered while processing the attached 7031** databases, SQLITE_OK is returned. 7032** 7033** If database zDb is the name of an attached database that is not in WAL 7034** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If 7035** zDb is not NULL (or a zero length string) and is not the name of any 7036** attached database, SQLITE_ERROR is returned to the caller. 7037*/ 7038int sqlite3_wal_checkpoint_v2( 7039 sqlite3 *db, /* Database handle */ 7040 const char *zDb, /* Name of attached database (or NULL) */ 7041 int eMode, /* SQLITE_CHECKPOINT_* value */ 7042 int *pnLog, /* OUT: Size of WAL log in frames */ 7043 int *pnCkpt /* OUT: Total number of frames checkpointed */ 7044); 7045 7046/* 7047** CAPI3REF: Checkpoint operation parameters 7048** 7049** These constants can be used as the 3rd parameter to 7050** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()] 7051** documentation for additional information about the meaning and use of 7052** each of these values. 7053*/ 7054#define SQLITE_CHECKPOINT_PASSIVE 0 7055#define SQLITE_CHECKPOINT_FULL 1 7056#define SQLITE_CHECKPOINT_RESTART 2 7057 7058/* 7059** CAPI3REF: Virtual Table Interface Configuration 7060** 7061** This function may be called by either the [xConnect] or [xCreate] method 7062** of a [virtual table] implementation to configure 7063** various facets of the virtual table interface. 7064** 7065** If this interface is invoked outside the context of an xConnect or 7066** xCreate virtual table method then the behavior is undefined. 7067** 7068** At present, there is only one option that may be configured using 7069** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 7070** may be added in the future. 7071*/ 7072int sqlite3_vtab_config(sqlite3*, int op, ...); 7073 7074/* 7075** CAPI3REF: Virtual Table Configuration Options 7076** 7077** These macros define the various options to the 7078** [sqlite3_vtab_config()] interface that [virtual table] implementations 7079** can use to customize and optimize their behavior. 7080** 7081** <dl> 7082** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 7083** <dd>Calls of the form 7084** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 7085** where X is an integer. If X is zero, then the [virtual table] whose 7086** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 7087** support constraints. In this configuration (which is the default) if 7088** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 7089** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 7090** specified as part of the users SQL statement, regardless of the actual 7091** ON CONFLICT mode specified. 7092** 7093** If X is non-zero, then the virtual table implementation guarantees 7094** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 7095** any modifications to internal or persistent data structures have been made. 7096** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 7097** is able to roll back a statement or database transaction, and abandon 7098** or continue processing the current SQL statement as appropriate. 7099** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 7100** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 7101** had been ABORT. 7102** 7103** Virtual table implementations that are required to handle OR REPLACE 7104** must do so within the [xUpdate] method. If a call to the 7105** [sqlite3_vtab_on_conflict()] function indicates that the current ON 7106** CONFLICT policy is REPLACE, the virtual table implementation should 7107** silently replace the appropriate rows within the xUpdate callback and 7108** return SQLITE_OK. Or, if this is not possible, it may return 7109** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 7110** constraint handling. 7111** </dl> 7112*/ 7113#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 7114 7115/* 7116** CAPI3REF: Determine The Virtual Table Conflict Policy 7117** 7118** This function may only be called from within a call to the [xUpdate] method 7119** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 7120** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 7121** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 7122** of the SQL statement that triggered the call to the [xUpdate] method of the 7123** [virtual table]. 7124*/ 7125int sqlite3_vtab_on_conflict(sqlite3 *); 7126 7127/* 7128** CAPI3REF: Conflict resolution modes 7129** 7130** These constants are returned by [sqlite3_vtab_on_conflict()] to 7131** inform a [virtual table] implementation what the [ON CONFLICT] mode 7132** is for the SQL statement being evaluated. 7133** 7134** Note that the [SQLITE_IGNORE] constant is also used as a potential 7135** return value from the [sqlite3_set_authorizer()] callback and that 7136** [SQLITE_ABORT] is also a [result code]. 7137*/ 7138#define SQLITE_ROLLBACK 1 7139/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 7140#define SQLITE_FAIL 3 7141/* #define SQLITE_ABORT 4 // Also an error code */ 7142#define SQLITE_REPLACE 5 7143 7144 7145 7146/* 7147** Undo the hack that converts floating point types to integer for 7148** builds on processors without floating point support. 7149*/ 7150#ifdef SQLITE_OMIT_FLOATING_POINT 7151# undef double 7152#endif 7153 7154#ifdef __cplusplus 7155} /* End of the 'extern "C"' block */ 7156#endif 7157#endif 7158