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