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