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** 856** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 857** ^This file-control may be invoked by SQLite on the database file handle 858** shortly after it is opened in order to provide a custom VFS with access 859** to the connections busy-handler callback. The argument is of type (void **) 860** - an array of two (void *) values. The first (void *) actually points 861** to a function of type (int (*)(void *)). In order to invoke the connections 862** busy-handler, this function should be invoked with the second (void *) in 863** the array as the only argument. If it returns non-zero, then the operation 864** should be retried. If it returns zero, the custom VFS should abandon the 865** current operation. 866** 867** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 868** ^Application can invoke this file-control to have SQLite generate a 869** temporary filename using the same algorithm that is followed to generate 870** temporary filenames for TEMP tables and other internal uses. The 871** argument should be a char** which will be filled with the filename 872** written into memory obtained from [sqlite3_malloc()]. The caller should 873** invoke [sqlite3_free()] on the result to avoid a memory leak. 874** 875** </ul> 876*/ 877#define SQLITE_FCNTL_LOCKSTATE 1 878#define SQLITE_GET_LOCKPROXYFILE 2 879#define SQLITE_SET_LOCKPROXYFILE 3 880#define SQLITE_LAST_ERRNO 4 881#define SQLITE_FCNTL_SIZE_HINT 5 882#define SQLITE_FCNTL_CHUNK_SIZE 6 883#define SQLITE_FCNTL_FILE_POINTER 7 884#define SQLITE_FCNTL_SYNC_OMITTED 8 885#define SQLITE_FCNTL_WIN32_AV_RETRY 9 886#define SQLITE_FCNTL_PERSIST_WAL 10 887#define SQLITE_FCNTL_OVERWRITE 11 888#define SQLITE_FCNTL_VFSNAME 12 889#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 890#define SQLITE_FCNTL_PRAGMA 14 891#define SQLITE_FCNTL_BUSYHANDLER 15 892#define SQLITE_FCNTL_TEMPFILENAME 16 893 894/* 895** CAPI3REF: Mutex Handle 896** 897** The mutex module within SQLite defines [sqlite3_mutex] to be an 898** abstract type for a mutex object. The SQLite core never looks 899** at the internal representation of an [sqlite3_mutex]. It only 900** deals with pointers to the [sqlite3_mutex] object. 901** 902** Mutexes are created using [sqlite3_mutex_alloc()]. 903*/ 904typedef struct sqlite3_mutex sqlite3_mutex; 905 906/* 907** CAPI3REF: OS Interface Object 908** 909** An instance of the sqlite3_vfs object defines the interface between 910** the SQLite core and the underlying operating system. The "vfs" 911** in the name of the object stands for "virtual file system". See 912** the [VFS | VFS documentation] for further information. 913** 914** The value of the iVersion field is initially 1 but may be larger in 915** future versions of SQLite. Additional fields may be appended to this 916** object when the iVersion value is increased. Note that the structure 917** of the sqlite3_vfs object changes in the transaction between 918** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 919** modified. 920** 921** The szOsFile field is the size of the subclassed [sqlite3_file] 922** structure used by this VFS. mxPathname is the maximum length of 923** a pathname in this VFS. 924** 925** Registered sqlite3_vfs objects are kept on a linked list formed by 926** the pNext pointer. The [sqlite3_vfs_register()] 927** and [sqlite3_vfs_unregister()] interfaces manage this list 928** in a thread-safe way. The [sqlite3_vfs_find()] interface 929** searches the list. Neither the application code nor the VFS 930** implementation should use the pNext pointer. 931** 932** The pNext field is the only field in the sqlite3_vfs 933** structure that SQLite will ever modify. SQLite will only access 934** or modify this field while holding a particular static mutex. 935** The application should never modify anything within the sqlite3_vfs 936** object once the object has been registered. 937** 938** The zName field holds the name of the VFS module. The name must 939** be unique across all VFS modules. 940** 941** [[sqlite3_vfs.xOpen]] 942** ^SQLite guarantees that the zFilename parameter to xOpen 943** is either a NULL pointer or string obtained 944** from xFullPathname() with an optional suffix added. 945** ^If a suffix is added to the zFilename parameter, it will 946** consist of a single "-" character followed by no more than 947** 11 alphanumeric and/or "-" characters. 948** ^SQLite further guarantees that 949** the string will be valid and unchanged until xClose() is 950** called. Because of the previous sentence, 951** the [sqlite3_file] can safely store a pointer to the 952** filename if it needs to remember the filename for some reason. 953** If the zFilename parameter to xOpen is a NULL pointer then xOpen 954** must invent its own temporary name for the file. ^Whenever the 955** xFilename parameter is NULL it will also be the case that the 956** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 957** 958** The flags argument to xOpen() includes all bits set in 959** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 960** or [sqlite3_open16()] is used, then flags includes at least 961** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 962** If xOpen() opens a file read-only then it sets *pOutFlags to 963** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 964** 965** ^(SQLite will also add one of the following flags to the xOpen() 966** call, depending on the object being opened: 967** 968** <ul> 969** <li> [SQLITE_OPEN_MAIN_DB] 970** <li> [SQLITE_OPEN_MAIN_JOURNAL] 971** <li> [SQLITE_OPEN_TEMP_DB] 972** <li> [SQLITE_OPEN_TEMP_JOURNAL] 973** <li> [SQLITE_OPEN_TRANSIENT_DB] 974** <li> [SQLITE_OPEN_SUBJOURNAL] 975** <li> [SQLITE_OPEN_MASTER_JOURNAL] 976** <li> [SQLITE_OPEN_WAL] 977** </ul>)^ 978** 979** The file I/O implementation can use the object type flags to 980** change the way it deals with files. For example, an application 981** that does not care about crash recovery or rollback might make 982** the open of a journal file a no-op. Writes to this journal would 983** also be no-ops, and any attempt to read the journal would return 984** SQLITE_IOERR. Or the implementation might recognize that a database 985** file will be doing page-aligned sector reads and writes in a random 986** order and set up its I/O subsystem accordingly. 987** 988** SQLite might also add one of the following flags to the xOpen method: 989** 990** <ul> 991** <li> [SQLITE_OPEN_DELETEONCLOSE] 992** <li> [SQLITE_OPEN_EXCLUSIVE] 993** </ul> 994** 995** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 996** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 997** will be set for TEMP databases and their journals, transient 998** databases, and subjournals. 999** 1000** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1001** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1002** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1003** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1004** SQLITE_OPEN_CREATE, is used to indicate that file should always 1005** be created, and that it is an error if it already exists. 1006** It is <i>not</i> used to indicate the file should be opened 1007** for exclusive access. 1008** 1009** ^At least szOsFile bytes of memory are allocated by SQLite 1010** to hold the [sqlite3_file] structure passed as the third 1011** argument to xOpen. The xOpen method does not have to 1012** allocate the structure; it should just fill it in. Note that 1013** the xOpen method must set the sqlite3_file.pMethods to either 1014** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1015** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1016** element will be valid after xOpen returns regardless of the success 1017** or failure of the xOpen call. 1018** 1019** [[sqlite3_vfs.xAccess]] 1020** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1021** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1022** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1023** to test whether a file is at least readable. The file can be a 1024** directory. 1025** 1026** ^SQLite will always allocate at least mxPathname+1 bytes for the 1027** output buffer xFullPathname. The exact size of the output buffer 1028** is also passed as a parameter to both methods. If the output buffer 1029** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1030** handled as a fatal error by SQLite, vfs implementations should endeavor 1031** to prevent this by setting mxPathname to a sufficiently large value. 1032** 1033** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1034** interfaces are not strictly a part of the filesystem, but they are 1035** included in the VFS structure for completeness. 1036** The xRandomness() function attempts to return nBytes bytes 1037** of good-quality randomness into zOut. The return value is 1038** the actual number of bytes of randomness obtained. 1039** The xSleep() method causes the calling thread to sleep for at 1040** least the number of microseconds given. ^The xCurrentTime() 1041** method returns a Julian Day Number for the current date and time as 1042** a floating point value. 1043** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1044** Day Number multiplied by 86400000 (the number of milliseconds in 1045** a 24-hour day). 1046** ^SQLite will use the xCurrentTimeInt64() method to get the current 1047** date and time if that method is available (if iVersion is 2 or 1048** greater and the function pointer is not NULL) and will fall back 1049** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1050** 1051** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1052** are not used by the SQLite core. These optional interfaces are provided 1053** by some VFSes to facilitate testing of the VFS code. By overriding 1054** system calls with functions under its control, a test program can 1055** simulate faults and error conditions that would otherwise be difficult 1056** or impossible to induce. The set of system calls that can be overridden 1057** varies from one VFS to another, and from one version of the same VFS to the 1058** next. Applications that use these interfaces must be prepared for any 1059** or all of these interfaces to be NULL or for their behavior to change 1060** from one release to the next. Applications must not attempt to access 1061** any of these methods if the iVersion of the VFS is less than 3. 1062*/ 1063typedef struct sqlite3_vfs sqlite3_vfs; 1064typedef void (*sqlite3_syscall_ptr)(void); 1065struct sqlite3_vfs { 1066 int iVersion; /* Structure version number (currently 3) */ 1067 int szOsFile; /* Size of subclassed sqlite3_file */ 1068 int mxPathname; /* Maximum file pathname length */ 1069 sqlite3_vfs *pNext; /* Next registered VFS */ 1070 const char *zName; /* Name of this virtual file system */ 1071 void *pAppData; /* Pointer to application-specific data */ 1072 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1073 int flags, int *pOutFlags); 1074 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1075 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1076 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1077 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1078 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1079 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1080 void (*xDlClose)(sqlite3_vfs*, void*); 1081 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1082 int (*xSleep)(sqlite3_vfs*, int microseconds); 1083 int (*xCurrentTime)(sqlite3_vfs*, double*); 1084 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1085 /* 1086 ** The methods above are in version 1 of the sqlite_vfs object 1087 ** definition. Those that follow are added in version 2 or later 1088 */ 1089 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1090 /* 1091 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1092 ** Those below are for version 3 and greater. 1093 */ 1094 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1095 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1096 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1097 /* 1098 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1099 ** New fields may be appended in figure versions. The iVersion 1100 ** value will increment whenever this happens. 1101 */ 1102}; 1103 1104/* 1105** CAPI3REF: Flags for the xAccess VFS method 1106** 1107** These integer constants can be used as the third parameter to 1108** the xAccess method of an [sqlite3_vfs] object. They determine 1109** what kind of permissions the xAccess method is looking for. 1110** With SQLITE_ACCESS_EXISTS, the xAccess method 1111** simply checks whether the file exists. 1112** With SQLITE_ACCESS_READWRITE, the xAccess method 1113** checks whether the named directory is both readable and writable 1114** (in other words, if files can be added, removed, and renamed within 1115** the directory). 1116** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1117** [temp_store_directory pragma], though this could change in a future 1118** release of SQLite. 1119** With SQLITE_ACCESS_READ, the xAccess method 1120** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1121** currently unused, though it might be used in a future release of 1122** SQLite. 1123*/ 1124#define SQLITE_ACCESS_EXISTS 0 1125#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1126#define SQLITE_ACCESS_READ 2 /* Unused */ 1127 1128/* 1129** CAPI3REF: Flags for the xShmLock VFS method 1130** 1131** These integer constants define the various locking operations 1132** allowed by the xShmLock method of [sqlite3_io_methods]. The 1133** following are the only legal combinations of flags to the 1134** xShmLock method: 1135** 1136** <ul> 1137** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1138** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1139** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1140** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1141** </ul> 1142** 1143** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1144** was given no the corresponding lock. 1145** 1146** The xShmLock method can transition between unlocked and SHARED or 1147** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1148** and EXCLUSIVE. 1149*/ 1150#define SQLITE_SHM_UNLOCK 1 1151#define SQLITE_SHM_LOCK 2 1152#define SQLITE_SHM_SHARED 4 1153#define SQLITE_SHM_EXCLUSIVE 8 1154 1155/* 1156** CAPI3REF: Maximum xShmLock index 1157** 1158** The xShmLock method on [sqlite3_io_methods] may use values 1159** between 0 and this upper bound as its "offset" argument. 1160** The SQLite core will never attempt to acquire or release a 1161** lock outside of this range 1162*/ 1163#define SQLITE_SHM_NLOCK 8 1164 1165 1166/* 1167** CAPI3REF: Initialize The SQLite Library 1168** 1169** ^The sqlite3_initialize() routine initializes the 1170** SQLite library. ^The sqlite3_shutdown() routine 1171** deallocates any resources that were allocated by sqlite3_initialize(). 1172** These routines are designed to aid in process initialization and 1173** shutdown on embedded systems. Workstation applications using 1174** SQLite normally do not need to invoke either of these routines. 1175** 1176** A call to sqlite3_initialize() is an "effective" call if it is 1177** the first time sqlite3_initialize() is invoked during the lifetime of 1178** the process, or if it is the first time sqlite3_initialize() is invoked 1179** following a call to sqlite3_shutdown(). ^(Only an effective call 1180** of sqlite3_initialize() does any initialization. All other calls 1181** are harmless no-ops.)^ 1182** 1183** A call to sqlite3_shutdown() is an "effective" call if it is the first 1184** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1185** an effective call to sqlite3_shutdown() does any deinitialization. 1186** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1187** 1188** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1189** is not. The sqlite3_shutdown() interface must only be called from a 1190** single thread. All open [database connections] must be closed and all 1191** other SQLite resources must be deallocated prior to invoking 1192** sqlite3_shutdown(). 1193** 1194** Among other things, ^sqlite3_initialize() will invoke 1195** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1196** will invoke sqlite3_os_end(). 1197** 1198** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1199** ^If for some reason, sqlite3_initialize() is unable to initialize 1200** the library (perhaps it is unable to allocate a needed resource such 1201** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1202** 1203** ^The sqlite3_initialize() routine is called internally by many other 1204** SQLite interfaces so that an application usually does not need to 1205** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1206** calls sqlite3_initialize() so the SQLite library will be automatically 1207** initialized when [sqlite3_open()] is called if it has not be initialized 1208** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1209** compile-time option, then the automatic calls to sqlite3_initialize() 1210** are omitted and the application must call sqlite3_initialize() directly 1211** prior to using any other SQLite interface. For maximum portability, 1212** it is recommended that applications always invoke sqlite3_initialize() 1213** directly prior to using any other SQLite interface. Future releases 1214** of SQLite may require this. In other words, the behavior exhibited 1215** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1216** default behavior in some future release of SQLite. 1217** 1218** The sqlite3_os_init() routine does operating-system specific 1219** initialization of the SQLite library. The sqlite3_os_end() 1220** routine undoes the effect of sqlite3_os_init(). Typical tasks 1221** performed by these routines include allocation or deallocation 1222** of static resources, initialization of global variables, 1223** setting up a default [sqlite3_vfs] module, or setting up 1224** a default configuration using [sqlite3_config()]. 1225** 1226** The application should never invoke either sqlite3_os_init() 1227** or sqlite3_os_end() directly. The application should only invoke 1228** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1229** interface is called automatically by sqlite3_initialize() and 1230** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1231** implementations for sqlite3_os_init() and sqlite3_os_end() 1232** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1233** When [custom builds | built for other platforms] 1234** (using the [SQLITE_OS_OTHER=1] compile-time 1235** option) the application must supply a suitable implementation for 1236** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1237** implementation of sqlite3_os_init() or sqlite3_os_end() 1238** must return [SQLITE_OK] on success and some other [error code] upon 1239** failure. 1240*/ 1241int sqlite3_initialize(void); 1242int sqlite3_shutdown(void); 1243int sqlite3_os_init(void); 1244int sqlite3_os_end(void); 1245 1246/* 1247** CAPI3REF: Configuring The SQLite Library 1248** 1249** The sqlite3_config() interface is used to make global configuration 1250** changes to SQLite in order to tune SQLite to the specific needs of 1251** the application. The default configuration is recommended for most 1252** applications and so this routine is usually not necessary. It is 1253** provided to support rare applications with unusual needs. 1254** 1255** The sqlite3_config() interface is not threadsafe. The application 1256** must insure that no other SQLite interfaces are invoked by other 1257** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1258** may only be invoked prior to library initialization using 1259** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1260** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1261** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1262** Note, however, that ^sqlite3_config() can be called as part of the 1263** implementation of an application-defined [sqlite3_os_init()]. 1264** 1265** The first argument to sqlite3_config() is an integer 1266** [configuration option] that determines 1267** what property of SQLite is to be configured. Subsequent arguments 1268** vary depending on the [configuration option] 1269** in the first argument. 1270** 1271** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1272** ^If the option is unknown or SQLite is unable to set the option 1273** then this routine returns a non-zero [error code]. 1274*/ 1275int sqlite3_config(int, ...); 1276 1277/* 1278** CAPI3REF: Configure database connections 1279** 1280** The sqlite3_db_config() interface is used to make configuration 1281** changes to a [database connection]. The interface is similar to 1282** [sqlite3_config()] except that the changes apply to a single 1283** [database connection] (specified in the first argument). 1284** 1285** The second argument to sqlite3_db_config(D,V,...) is the 1286** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1287** that indicates what aspect of the [database connection] is being configured. 1288** Subsequent arguments vary depending on the configuration verb. 1289** 1290** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1291** the call is considered successful. 1292*/ 1293int sqlite3_db_config(sqlite3*, int op, ...); 1294 1295/* 1296** CAPI3REF: Memory Allocation Routines 1297** 1298** An instance of this object defines the interface between SQLite 1299** and low-level memory allocation routines. 1300** 1301** This object is used in only one place in the SQLite interface. 1302** A pointer to an instance of this object is the argument to 1303** [sqlite3_config()] when the configuration option is 1304** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1305** By creating an instance of this object 1306** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1307** during configuration, an application can specify an alternative 1308** memory allocation subsystem for SQLite to use for all of its 1309** dynamic memory needs. 1310** 1311** Note that SQLite comes with several [built-in memory allocators] 1312** that are perfectly adequate for the overwhelming majority of applications 1313** and that this object is only useful to a tiny minority of applications 1314** with specialized memory allocation requirements. This object is 1315** also used during testing of SQLite in order to specify an alternative 1316** memory allocator that simulates memory out-of-memory conditions in 1317** order to verify that SQLite recovers gracefully from such 1318** conditions. 1319** 1320** The xMalloc, xRealloc, and xFree methods must work like the 1321** malloc(), realloc() and free() functions from the standard C library. 1322** ^SQLite guarantees that the second argument to 1323** xRealloc is always a value returned by a prior call to xRoundup. 1324** 1325** xSize should return the allocated size of a memory allocation 1326** previously obtained from xMalloc or xRealloc. The allocated size 1327** is always at least as big as the requested size but may be larger. 1328** 1329** The xRoundup method returns what would be the allocated size of 1330** a memory allocation given a particular requested size. Most memory 1331** allocators round up memory allocations at least to the next multiple 1332** of 8. Some allocators round up to a larger multiple or to a power of 2. 1333** Every memory allocation request coming in through [sqlite3_malloc()] 1334** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1335** that causes the corresponding memory allocation to fail. 1336** 1337** The xInit method initializes the memory allocator. (For example, 1338** it might allocate any require mutexes or initialize internal data 1339** structures. The xShutdown method is invoked (indirectly) by 1340** [sqlite3_shutdown()] and should deallocate any resources acquired 1341** by xInit. The pAppData pointer is used as the only parameter to 1342** xInit and xShutdown. 1343** 1344** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1345** the xInit method, so the xInit method need not be threadsafe. The 1346** xShutdown method is only called from [sqlite3_shutdown()] so it does 1347** not need to be threadsafe either. For all other methods, SQLite 1348** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1349** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1350** it is by default) and so the methods are automatically serialized. 1351** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1352** methods must be threadsafe or else make their own arrangements for 1353** serialization. 1354** 1355** SQLite will never invoke xInit() more than once without an intervening 1356** call to xShutdown(). 1357*/ 1358typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1359struct sqlite3_mem_methods { 1360 void *(*xMalloc)(int); /* Memory allocation function */ 1361 void (*xFree)(void*); /* Free a prior allocation */ 1362 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1363 int (*xSize)(void*); /* Return the size of an allocation */ 1364 int (*xRoundup)(int); /* Round up request size to allocation size */ 1365 int (*xInit)(void*); /* Initialize the memory allocator */ 1366 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1367 void *pAppData; /* Argument to xInit() and xShutdown() */ 1368}; 1369 1370/* 1371** CAPI3REF: Configuration Options 1372** KEYWORDS: {configuration option} 1373** 1374** These constants are the available integer configuration options that 1375** can be passed as the first argument to the [sqlite3_config()] interface. 1376** 1377** New configuration options may be added in future releases of SQLite. 1378** Existing configuration options might be discontinued. Applications 1379** should check the return code from [sqlite3_config()] to make sure that 1380** the call worked. The [sqlite3_config()] interface will return a 1381** non-zero [error code] if a discontinued or unsupported configuration option 1382** is invoked. 1383** 1384** <dl> 1385** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1386** <dd>There are no arguments to this option. ^This option sets the 1387** [threading mode] to Single-thread. In other words, it disables 1388** all mutexing and puts SQLite into a mode where it can only be used 1389** by a single thread. ^If SQLite is compiled with 1390** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1391** it is not possible to change the [threading mode] from its default 1392** value of Single-thread and so [sqlite3_config()] will return 1393** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1394** configuration option.</dd> 1395** 1396** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1397** <dd>There are no arguments to this option. ^This option sets the 1398** [threading mode] to Multi-thread. In other words, it disables 1399** mutexing on [database connection] and [prepared statement] objects. 1400** The application is responsible for serializing access to 1401** [database connections] and [prepared statements]. But other mutexes 1402** are enabled so that SQLite will be safe to use in a multi-threaded 1403** environment as long as no two threads attempt to use the same 1404** [database connection] at the same time. ^If SQLite is compiled with 1405** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1406** it is not possible to set the Multi-thread [threading mode] and 1407** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1408** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1409** 1410** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1411** <dd>There are no arguments to this option. ^This option sets the 1412** [threading mode] to Serialized. In other words, this option enables 1413** all mutexes including the recursive 1414** mutexes on [database connection] and [prepared statement] objects. 1415** In this mode (which is the default when SQLite is compiled with 1416** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1417** to [database connections] and [prepared statements] so that the 1418** application is free to use the same [database connection] or the 1419** same [prepared statement] in different threads at the same time. 1420** ^If SQLite is compiled with 1421** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1422** it is not possible to set the Serialized [threading mode] and 1423** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1424** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1425** 1426** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1427** <dd> ^(This option takes a single argument which is a pointer to an 1428** instance of the [sqlite3_mem_methods] structure. The argument specifies 1429** alternative low-level memory allocation routines to be used in place of 1430** the memory allocation routines built into SQLite.)^ ^SQLite makes 1431** its own private copy of the content of the [sqlite3_mem_methods] structure 1432** before the [sqlite3_config()] call returns.</dd> 1433** 1434** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1435** <dd> ^(This option takes a single argument which is a pointer to an 1436** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1437** structure is filled with the currently defined memory allocation routines.)^ 1438** This option can be used to overload the default memory allocation 1439** routines with a wrapper that simulations memory allocation failure or 1440** tracks memory usage, for example. </dd> 1441** 1442** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1443** <dd> ^This option takes single argument of type int, interpreted as a 1444** boolean, which enables or disables the collection of memory allocation 1445** statistics. ^(When memory allocation statistics are disabled, the 1446** following SQLite interfaces become non-operational: 1447** <ul> 1448** <li> [sqlite3_memory_used()] 1449** <li> [sqlite3_memory_highwater()] 1450** <li> [sqlite3_soft_heap_limit64()] 1451** <li> [sqlite3_status()] 1452** </ul>)^ 1453** ^Memory allocation statistics are enabled by default unless SQLite is 1454** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1455** allocation statistics are disabled by default. 1456** </dd> 1457** 1458** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1459** <dd> ^This option specifies a static memory buffer that SQLite can use for 1460** scratch memory. There are three arguments: A pointer an 8-byte 1461** aligned memory buffer from which the scratch allocations will be 1462** drawn, the size of each scratch allocation (sz), 1463** and the maximum number of scratch allocations (N). The sz 1464** argument must be a multiple of 16. 1465** The first argument must be a pointer to an 8-byte aligned buffer 1466** of at least sz*N bytes of memory. 1467** ^SQLite will use no more than two scratch buffers per thread. So 1468** N should be set to twice the expected maximum number of threads. 1469** ^SQLite will never require a scratch buffer that is more than 6 1470** times the database page size. ^If SQLite needs needs additional 1471** scratch memory beyond what is provided by this configuration option, then 1472** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1473** 1474** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1475** <dd> ^This option specifies a static memory buffer that SQLite can use for 1476** the database page cache with the default page cache implementation. 1477** This configuration should not be used if an application-define page 1478** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option. 1479** There are three arguments to this option: A pointer to 8-byte aligned 1480** memory, the size of each page buffer (sz), and the number of pages (N). 1481** The sz argument should be the size of the largest database page 1482** (a power of two between 512 and 32768) plus a little extra for each 1483** page header. ^The page header size is 20 to 40 bytes depending on 1484** the host architecture. ^It is harmless, apart from the wasted memory, 1485** to make sz a little too large. The first 1486** argument should point to an allocation of at least sz*N bytes of memory. 1487** ^SQLite will use the memory provided by the first argument to satisfy its 1488** memory needs for the first N pages that it adds to cache. ^If additional 1489** page cache memory is needed beyond what is provided by this option, then 1490** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1491** The pointer in the first argument must 1492** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1493** will be undefined.</dd> 1494** 1495** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1496** <dd> ^This option specifies a static memory buffer that SQLite will use 1497** for all of its dynamic memory allocation needs beyond those provided 1498** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1499** There are three arguments: An 8-byte aligned pointer to the memory, 1500** the number of bytes in the memory buffer, and the minimum allocation size. 1501** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1502** to using its default memory allocator (the system malloc() implementation), 1503** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1504** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1505** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1506** allocator is engaged to handle all of SQLites memory allocation needs. 1507** The first pointer (the memory pointer) must be aligned to an 8-byte 1508** boundary or subsequent behavior of SQLite will be undefined. 1509** The minimum allocation size is capped at 2**12. Reasonable values 1510** for the minimum allocation size are 2**5 through 2**8.</dd> 1511** 1512** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1513** <dd> ^(This option takes a single argument which is a pointer to an 1514** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1515** alternative low-level mutex routines to be used in place 1516** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1517** content of the [sqlite3_mutex_methods] structure before the call to 1518** [sqlite3_config()] returns. ^If SQLite is compiled with 1519** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1520** the entire mutexing subsystem is omitted from the build and hence calls to 1521** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1522** return [SQLITE_ERROR].</dd> 1523** 1524** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1525** <dd> ^(This option takes a single argument which is a pointer to an 1526** instance of the [sqlite3_mutex_methods] structure. The 1527** [sqlite3_mutex_methods] 1528** structure is filled with the currently defined mutex routines.)^ 1529** This option can be used to overload the default mutex allocation 1530** routines with a wrapper used to track mutex usage for performance 1531** profiling or testing, for example. ^If SQLite is compiled with 1532** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1533** the entire mutexing subsystem is omitted from the build and hence calls to 1534** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1535** return [SQLITE_ERROR].</dd> 1536** 1537** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1538** <dd> ^(This option takes two arguments that determine the default 1539** memory allocation for the lookaside memory allocator on each 1540** [database connection]. The first argument is the 1541** size of each lookaside buffer slot and the second is the number of 1542** slots allocated to each database connection.)^ ^(This option sets the 1543** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1544** verb to [sqlite3_db_config()] can be used to change the lookaside 1545** configuration on individual connections.)^ </dd> 1546** 1547** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1548** <dd> ^(This option takes a single argument which is a pointer to 1549** an [sqlite3_pcache_methods2] object. This object specifies the interface 1550** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1551** object and uses it for page cache memory allocations.</dd> 1552** 1553** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1554** <dd> ^(This option takes a single argument which is a pointer to an 1555** [sqlite3_pcache_methods2] object. SQLite copies of the current 1556** page cache implementation into that object.)^ </dd> 1557** 1558** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1559** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1560** function with a call signature of void(*)(void*,int,const char*), 1561** and a pointer to void. ^If the function pointer is not NULL, it is 1562** invoked by [sqlite3_log()] to process each logging event. ^If the 1563** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1564** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1565** passed through as the first parameter to the application-defined logger 1566** function whenever that function is invoked. ^The second parameter to 1567** the logger function is a copy of the first parameter to the corresponding 1568** [sqlite3_log()] call and is intended to be a [result code] or an 1569** [extended result code]. ^The third parameter passed to the logger is 1570** log message after formatting via [sqlite3_snprintf()]. 1571** The SQLite logging interface is not reentrant; the logger function 1572** supplied by the application must not invoke any SQLite interface. 1573** In a multi-threaded application, the application-defined logger 1574** function must be threadsafe. </dd> 1575** 1576** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1577** <dd> This option takes a single argument of type int. If non-zero, then 1578** URI handling is globally enabled. If the parameter is zero, then URI handling 1579** is globally disabled. If URI handling is globally enabled, all filenames 1580** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or 1581** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1582** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1583** connection is opened. If it is globally disabled, filenames are 1584** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1585** database connection is opened. By default, URI handling is globally 1586** disabled. The default value may be changed by compiling with the 1587** [SQLITE_USE_URI] symbol defined. 1588** 1589** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1590** <dd> This option taks a single integer argument which is interpreted as 1591** a boolean in order to enable or disable the use of covering indices for 1592** full table scans in the query optimizer. The default setting is determined 1593** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1594** if that compile-time option is omitted. 1595** The ability to disable the use of covering indices for full table scans 1596** is because some incorrectly coded legacy applications might malfunction 1597** malfunction when the optimization is enabled. Providing the ability to 1598** disable the optimization allows the older, buggy application code to work 1599** without change even with newer versions of SQLite. 1600** 1601** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1602** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1603** <dd> These options are obsolete and should not be used by new code. 1604** They are retained for backwards compatibility but are now no-ops. 1605** </dl> 1606** 1607** [[SQLITE_CONFIG_SQLLOG]] 1608** <dt>SQLITE_CONFIG_SQLLOG 1609** <dd>This option is only available if sqlite is compiled with the 1610** SQLITE_ENABLE_SQLLOG pre-processor macro defined. The first argument should 1611** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1612** The second should be of type (void*). The callback is invoked by the library 1613** in three separate circumstances, identified by the value passed as the 1614** fourth parameter. If the fourth parameter is 0, then the database connection 1615** passed as the second argument has just been opened. The third argument 1616** points to a buffer containing the name of the main database file. If the 1617** fourth parameter is 1, then the SQL statement that the third parameter 1618** points to has just been executed. Or, if the fourth parameter is 2, then 1619** the connection being passed as the second parameter is being closed. The 1620** third parameter is passed NULL In this case. 1621** </dl> 1622*/ 1623#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1624#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1625#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1626#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1627#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1628#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1629#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1630#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1631#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1632#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1633#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1634/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1635#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1636#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1637#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1638#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1639#define SQLITE_CONFIG_URI 17 /* int */ 1640#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1641#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1642#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1643#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1644 1645/* 1646** CAPI3REF: Database Connection Configuration Options 1647** 1648** These constants are the available integer configuration options that 1649** can be passed as the second argument to the [sqlite3_db_config()] interface. 1650** 1651** New configuration options may be added in future releases of SQLite. 1652** Existing configuration options might be discontinued. Applications 1653** should check the return code from [sqlite3_db_config()] to make sure that 1654** the call worked. ^The [sqlite3_db_config()] interface will return a 1655** non-zero [error code] if a discontinued or unsupported configuration option 1656** is invoked. 1657** 1658** <dl> 1659** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1660** <dd> ^This option takes three additional arguments that determine the 1661** [lookaside memory allocator] configuration for the [database connection]. 1662** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1663** pointer to a memory buffer to use for lookaside memory. 1664** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1665** may be NULL in which case SQLite will allocate the 1666** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1667** size of each lookaside buffer slot. ^The third argument is the number of 1668** slots. The size of the buffer in the first argument must be greater than 1669** or equal to the product of the second and third arguments. The buffer 1670** must be aligned to an 8-byte boundary. ^If the second argument to 1671** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1672** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1673** configuration for a database connection can only be changed when that 1674** connection is not currently using lookaside memory, or in other words 1675** when the "current value" returned by 1676** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1677** Any attempt to change the lookaside memory configuration when lookaside 1678** memory is in use leaves the configuration unchanged and returns 1679** [SQLITE_BUSY].)^</dd> 1680** 1681** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1682** <dd> ^This option is used to enable or disable the enforcement of 1683** [foreign key constraints]. There should be two additional arguments. 1684** The first argument is an integer which is 0 to disable FK enforcement, 1685** positive to enable FK enforcement or negative to leave FK enforcement 1686** unchanged. The second parameter is a pointer to an integer into which 1687** is written 0 or 1 to indicate whether FK enforcement is off or on 1688** following this call. The second parameter may be a NULL pointer, in 1689** which case the FK enforcement setting is not reported back. </dd> 1690** 1691** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1692** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1693** There should be two additional arguments. 1694** The first argument is an integer which is 0 to disable triggers, 1695** positive to enable triggers or negative to leave the setting unchanged. 1696** The second parameter is a pointer to an integer into which 1697** is written 0 or 1 to indicate whether triggers are disabled or enabled 1698** following this call. The second parameter may be a NULL pointer, in 1699** which case the trigger setting is not reported back. </dd> 1700** 1701** </dl> 1702*/ 1703#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1704#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1705#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1706 1707 1708/* 1709** CAPI3REF: Enable Or Disable Extended Result Codes 1710** 1711** ^The sqlite3_extended_result_codes() routine enables or disables the 1712** [extended result codes] feature of SQLite. ^The extended result 1713** codes are disabled by default for historical compatibility. 1714*/ 1715int sqlite3_extended_result_codes(sqlite3*, int onoff); 1716 1717/* 1718** CAPI3REF: Last Insert Rowid 1719** 1720** ^Each entry in an SQLite table has a unique 64-bit signed 1721** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1722** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1723** names are not also used by explicitly declared columns. ^If 1724** the table has a column of type [INTEGER PRIMARY KEY] then that column 1725** is another alias for the rowid. 1726** 1727** ^This routine returns the [rowid] of the most recent 1728** successful [INSERT] into the database from the [database connection] 1729** in the first argument. ^As of SQLite version 3.7.7, this routines 1730** records the last insert rowid of both ordinary tables and [virtual tables]. 1731** ^If no successful [INSERT]s 1732** have ever occurred on that database connection, zero is returned. 1733** 1734** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1735** method, then this routine will return the [rowid] of the inserted 1736** row as long as the trigger or virtual table method is running. 1737** But once the trigger or virtual table method ends, the value returned 1738** by this routine reverts to what it was before the trigger or virtual 1739** table method began.)^ 1740** 1741** ^An [INSERT] that fails due to a constraint violation is not a 1742** successful [INSERT] and does not change the value returned by this 1743** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1744** and INSERT OR ABORT make no changes to the return value of this 1745** routine when their insertion fails. ^(When INSERT OR REPLACE 1746** encounters a constraint violation, it does not fail. The 1747** INSERT continues to completion after deleting rows that caused 1748** the constraint problem so INSERT OR REPLACE will always change 1749** the return value of this interface.)^ 1750** 1751** ^For the purposes of this routine, an [INSERT] is considered to 1752** be successful even if it is subsequently rolled back. 1753** 1754** This function is accessible to SQL statements via the 1755** [last_insert_rowid() SQL function]. 1756** 1757** If a separate thread performs a new [INSERT] on the same 1758** database connection while the [sqlite3_last_insert_rowid()] 1759** function is running and thus changes the last insert [rowid], 1760** then the value returned by [sqlite3_last_insert_rowid()] is 1761** unpredictable and might not equal either the old or the new 1762** last insert [rowid]. 1763*/ 1764sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1765 1766/* 1767** CAPI3REF: Count The Number Of Rows Modified 1768** 1769** ^This function returns the number of database rows that were changed 1770** or inserted or deleted by the most recently completed SQL statement 1771** on the [database connection] specified by the first parameter. 1772** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1773** or [DELETE] statement are counted. Auxiliary changes caused by 1774** triggers or [foreign key actions] are not counted.)^ Use the 1775** [sqlite3_total_changes()] function to find the total number of changes 1776** including changes caused by triggers and foreign key actions. 1777** 1778** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1779** are not counted. Only real table changes are counted. 1780** 1781** ^(A "row change" is a change to a single row of a single table 1782** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1783** are changed as side effects of [REPLACE] constraint resolution, 1784** rollback, ABORT processing, [DROP TABLE], or by any other 1785** mechanisms do not count as direct row changes.)^ 1786** 1787** A "trigger context" is a scope of execution that begins and 1788** ends with the script of a [CREATE TRIGGER | trigger]. 1789** Most SQL statements are 1790** evaluated outside of any trigger. This is the "top level" 1791** trigger context. If a trigger fires from the top level, a 1792** new trigger context is entered for the duration of that one 1793** trigger. Subtriggers create subcontexts for their duration. 1794** 1795** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1796** not create a new trigger context. 1797** 1798** ^This function returns the number of direct row changes in the 1799** most recent INSERT, UPDATE, or DELETE statement within the same 1800** trigger context. 1801** 1802** ^Thus, when called from the top level, this function returns the 1803** number of changes in the most recent INSERT, UPDATE, or DELETE 1804** that also occurred at the top level. ^(Within the body of a trigger, 1805** the sqlite3_changes() interface can be called to find the number of 1806** changes in the most recently completed INSERT, UPDATE, or DELETE 1807** statement within the body of the same trigger. 1808** However, the number returned does not include changes 1809** caused by subtriggers since those have their own context.)^ 1810** 1811** See also the [sqlite3_total_changes()] interface, the 1812** [count_changes pragma], and the [changes() SQL function]. 1813** 1814** If a separate thread makes changes on the same database connection 1815** while [sqlite3_changes()] is running then the value returned 1816** is unpredictable and not meaningful. 1817*/ 1818int sqlite3_changes(sqlite3*); 1819 1820/* 1821** CAPI3REF: Total Number Of Rows Modified 1822** 1823** ^This function returns the number of row changes caused by [INSERT], 1824** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1825** ^(The count returned by sqlite3_total_changes() includes all changes 1826** from all [CREATE TRIGGER | trigger] contexts and changes made by 1827** [foreign key actions]. However, 1828** the count does not include changes used to implement [REPLACE] constraints, 1829** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1830** count does not include rows of views that fire an [INSTEAD OF trigger], 1831** though if the INSTEAD OF trigger makes changes of its own, those changes 1832** are counted.)^ 1833** ^The sqlite3_total_changes() function counts the changes as soon as 1834** the statement that makes them is completed (when the statement handle 1835** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1836** 1837** See also the [sqlite3_changes()] interface, the 1838** [count_changes pragma], and the [total_changes() SQL function]. 1839** 1840** If a separate thread makes changes on the same database connection 1841** while [sqlite3_total_changes()] is running then the value 1842** returned is unpredictable and not meaningful. 1843*/ 1844int sqlite3_total_changes(sqlite3*); 1845 1846/* 1847** CAPI3REF: Interrupt A Long-Running Query 1848** 1849** ^This function causes any pending database operation to abort and 1850** return at its earliest opportunity. This routine is typically 1851** called in response to a user action such as pressing "Cancel" 1852** or Ctrl-C where the user wants a long query operation to halt 1853** immediately. 1854** 1855** ^It is safe to call this routine from a thread different from the 1856** thread that is currently running the database operation. But it 1857** is not safe to call this routine with a [database connection] that 1858** is closed or might close before sqlite3_interrupt() returns. 1859** 1860** ^If an SQL operation is very nearly finished at the time when 1861** sqlite3_interrupt() is called, then it might not have an opportunity 1862** to be interrupted and might continue to completion. 1863** 1864** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1865** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1866** that is inside an explicit transaction, then the entire transaction 1867** will be rolled back automatically. 1868** 1869** ^The sqlite3_interrupt(D) call is in effect until all currently running 1870** SQL statements on [database connection] D complete. ^Any new SQL statements 1871** that are started after the sqlite3_interrupt() call and before the 1872** running statements reaches zero are interrupted as if they had been 1873** running prior to the sqlite3_interrupt() call. ^New SQL statements 1874** that are started after the running statement count reaches zero are 1875** not effected by the sqlite3_interrupt(). 1876** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1877** SQL statements is a no-op and has no effect on SQL statements 1878** that are started after the sqlite3_interrupt() call returns. 1879** 1880** If the database connection closes while [sqlite3_interrupt()] 1881** is running then bad things will likely happen. 1882*/ 1883void sqlite3_interrupt(sqlite3*); 1884 1885/* 1886** CAPI3REF: Determine If An SQL Statement Is Complete 1887** 1888** These routines are useful during command-line input to determine if the 1889** currently entered text seems to form a complete SQL statement or 1890** if additional input is needed before sending the text into 1891** SQLite for parsing. ^These routines return 1 if the input string 1892** appears to be a complete SQL statement. ^A statement is judged to be 1893** complete if it ends with a semicolon token and is not a prefix of a 1894** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1895** string literals or quoted identifier names or comments are not 1896** independent tokens (they are part of the token in which they are 1897** embedded) and thus do not count as a statement terminator. ^Whitespace 1898** and comments that follow the final semicolon are ignored. 1899** 1900** ^These routines return 0 if the statement is incomplete. ^If a 1901** memory allocation fails, then SQLITE_NOMEM is returned. 1902** 1903** ^These routines do not parse the SQL statements thus 1904** will not detect syntactically incorrect SQL. 1905** 1906** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1907** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1908** automatically by sqlite3_complete16(). If that initialization fails, 1909** then the return value from sqlite3_complete16() will be non-zero 1910** regardless of whether or not the input SQL is complete.)^ 1911** 1912** The input to [sqlite3_complete()] must be a zero-terminated 1913** UTF-8 string. 1914** 1915** The input to [sqlite3_complete16()] must be a zero-terminated 1916** UTF-16 string in native byte order. 1917*/ 1918int sqlite3_complete(const char *sql); 1919int sqlite3_complete16(const void *sql); 1920 1921/* 1922** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1923** 1924** ^This routine sets a callback function that might be invoked whenever 1925** an attempt is made to open a database table that another thread 1926** or process has locked. 1927** 1928** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1929** is returned immediately upon encountering the lock. ^If the busy callback 1930** is not NULL, then the callback might be invoked with two arguments. 1931** 1932** ^The first argument to the busy handler is a copy of the void* pointer which 1933** is the third argument to sqlite3_busy_handler(). ^The second argument to 1934** the busy handler callback is the number of times that the busy handler has 1935** been invoked for this locking event. ^If the 1936** busy callback returns 0, then no additional attempts are made to 1937** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1938** ^If the callback returns non-zero, then another attempt 1939** is made to open the database for reading and the cycle repeats. 1940** 1941** The presence of a busy handler does not guarantee that it will be invoked 1942** when there is lock contention. ^If SQLite determines that invoking the busy 1943** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1944** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1945** Consider a scenario where one process is holding a read lock that 1946** it is trying to promote to a reserved lock and 1947** a second process is holding a reserved lock that it is trying 1948** to promote to an exclusive lock. The first process cannot proceed 1949** because it is blocked by the second and the second process cannot 1950** proceed because it is blocked by the first. If both processes 1951** invoke the busy handlers, neither will make any progress. Therefore, 1952** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1953** will induce the first process to release its read lock and allow 1954** the second process to proceed. 1955** 1956** ^The default busy callback is NULL. 1957** 1958** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1959** when SQLite is in the middle of a large transaction where all the 1960** changes will not fit into the in-memory cache. SQLite will 1961** already hold a RESERVED lock on the database file, but it needs 1962** to promote this lock to EXCLUSIVE so that it can spill cache 1963** pages into the database file without harm to concurrent 1964** readers. ^If it is unable to promote the lock, then the in-memory 1965** cache will be left in an inconsistent state and so the error 1966** code is promoted from the relatively benign [SQLITE_BUSY] to 1967** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 1968** forces an automatic rollback of the changes. See the 1969** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1970** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1971** this is important. 1972** 1973** ^(There can only be a single busy handler defined for each 1974** [database connection]. Setting a new busy handler clears any 1975** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 1976** will also set or clear the busy handler. 1977** 1978** The busy callback should not take any actions which modify the 1979** database connection that invoked the busy handler. Any such actions 1980** result in undefined behavior. 1981** 1982** A busy handler must not close the database connection 1983** or [prepared statement] that invoked the busy handler. 1984*/ 1985int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1986 1987/* 1988** CAPI3REF: Set A Busy Timeout 1989** 1990** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1991** for a specified amount of time when a table is locked. ^The handler 1992** will sleep multiple times until at least "ms" milliseconds of sleeping 1993** have accumulated. ^After at least "ms" milliseconds of sleeping, 1994** the handler returns 0 which causes [sqlite3_step()] to return 1995** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1996** 1997** ^Calling this routine with an argument less than or equal to zero 1998** turns off all busy handlers. 1999** 2000** ^(There can only be a single busy handler for a particular 2001** [database connection] any any given moment. If another busy handler 2002** was defined (using [sqlite3_busy_handler()]) prior to calling 2003** this routine, that other busy handler is cleared.)^ 2004*/ 2005int sqlite3_busy_timeout(sqlite3*, int ms); 2006 2007/* 2008** CAPI3REF: Convenience Routines For Running Queries 2009** 2010** This is a legacy interface that is preserved for backwards compatibility. 2011** Use of this interface is not recommended. 2012** 2013** Definition: A <b>result table</b> is memory data structure created by the 2014** [sqlite3_get_table()] interface. A result table records the 2015** complete query results from one or more queries. 2016** 2017** The table conceptually has a number of rows and columns. But 2018** these numbers are not part of the result table itself. These 2019** numbers are obtained separately. Let N be the number of rows 2020** and M be the number of columns. 2021** 2022** A result table is an array of pointers to zero-terminated UTF-8 strings. 2023** There are (N+1)*M elements in the array. The first M pointers point 2024** to zero-terminated strings that contain the names of the columns. 2025** The remaining entries all point to query results. NULL values result 2026** in NULL pointers. All other values are in their UTF-8 zero-terminated 2027** string representation as returned by [sqlite3_column_text()]. 2028** 2029** A result table might consist of one or more memory allocations. 2030** It is not safe to pass a result table directly to [sqlite3_free()]. 2031** A result table should be deallocated using [sqlite3_free_table()]. 2032** 2033** ^(As an example of the result table format, suppose a query result 2034** is as follows: 2035** 2036** <blockquote><pre> 2037** Name | Age 2038** ----------------------- 2039** Alice | 43 2040** Bob | 28 2041** Cindy | 21 2042** </pre></blockquote> 2043** 2044** There are two column (M==2) and three rows (N==3). Thus the 2045** result table has 8 entries. Suppose the result table is stored 2046** in an array names azResult. Then azResult holds this content: 2047** 2048** <blockquote><pre> 2049** azResult[0] = "Name"; 2050** azResult[1] = "Age"; 2051** azResult[2] = "Alice"; 2052** azResult[3] = "43"; 2053** azResult[4] = "Bob"; 2054** azResult[5] = "28"; 2055** azResult[6] = "Cindy"; 2056** azResult[7] = "21"; 2057** </pre></blockquote>)^ 2058** 2059** ^The sqlite3_get_table() function evaluates one or more 2060** semicolon-separated SQL statements in the zero-terminated UTF-8 2061** string of its 2nd parameter and returns a result table to the 2062** pointer given in its 3rd parameter. 2063** 2064** After the application has finished with the result from sqlite3_get_table(), 2065** it must pass the result table pointer to sqlite3_free_table() in order to 2066** release the memory that was malloced. Because of the way the 2067** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2068** function must not try to call [sqlite3_free()] directly. Only 2069** [sqlite3_free_table()] is able to release the memory properly and safely. 2070** 2071** The sqlite3_get_table() interface is implemented as a wrapper around 2072** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2073** to any internal data structures of SQLite. It uses only the public 2074** interface defined here. As a consequence, errors that occur in the 2075** wrapper layer outside of the internal [sqlite3_exec()] call are not 2076** reflected in subsequent calls to [sqlite3_errcode()] or 2077** [sqlite3_errmsg()]. 2078*/ 2079int sqlite3_get_table( 2080 sqlite3 *db, /* An open database */ 2081 const char *zSql, /* SQL to be evaluated */ 2082 char ***pazResult, /* Results of the query */ 2083 int *pnRow, /* Number of result rows written here */ 2084 int *pnColumn, /* Number of result columns written here */ 2085 char **pzErrmsg /* Error msg written here */ 2086); 2087void sqlite3_free_table(char **result); 2088 2089/* 2090** CAPI3REF: Formatted String Printing Functions 2091** 2092** These routines are work-alikes of the "printf()" family of functions 2093** from the standard C library. 2094** 2095** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2096** results into memory obtained from [sqlite3_malloc()]. 2097** The strings returned by these two routines should be 2098** released by [sqlite3_free()]. ^Both routines return a 2099** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2100** memory to hold the resulting string. 2101** 2102** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2103** the standard C library. The result is written into the 2104** buffer supplied as the second parameter whose size is given by 2105** the first parameter. Note that the order of the 2106** first two parameters is reversed from snprintf().)^ This is an 2107** historical accident that cannot be fixed without breaking 2108** backwards compatibility. ^(Note also that sqlite3_snprintf() 2109** returns a pointer to its buffer instead of the number of 2110** characters actually written into the buffer.)^ We admit that 2111** the number of characters written would be a more useful return 2112** value but we cannot change the implementation of sqlite3_snprintf() 2113** now without breaking compatibility. 2114** 2115** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2116** guarantees that the buffer is always zero-terminated. ^The first 2117** parameter "n" is the total size of the buffer, including space for 2118** the zero terminator. So the longest string that can be completely 2119** written will be n-1 characters. 2120** 2121** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2122** 2123** These routines all implement some additional formatting 2124** options that are useful for constructing SQL statements. 2125** All of the usual printf() formatting options apply. In addition, there 2126** is are "%q", "%Q", and "%z" options. 2127** 2128** ^(The %q option works like %s in that it substitutes a nul-terminated 2129** string from the argument list. But %q also doubles every '\'' character. 2130** %q is designed for use inside a string literal.)^ By doubling each '\'' 2131** character it escapes that character and allows it to be inserted into 2132** the string. 2133** 2134** For example, assume the string variable zText contains text as follows: 2135** 2136** <blockquote><pre> 2137** char *zText = "It's a happy day!"; 2138** </pre></blockquote> 2139** 2140** One can use this text in an SQL statement as follows: 2141** 2142** <blockquote><pre> 2143** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2144** sqlite3_exec(db, zSQL, 0, 0, 0); 2145** sqlite3_free(zSQL); 2146** </pre></blockquote> 2147** 2148** Because the %q format string is used, the '\'' character in zText 2149** is escaped and the SQL generated is as follows: 2150** 2151** <blockquote><pre> 2152** INSERT INTO table1 VALUES('It''s a happy day!') 2153** </pre></blockquote> 2154** 2155** This is correct. Had we used %s instead of %q, the generated SQL 2156** would have looked like this: 2157** 2158** <blockquote><pre> 2159** INSERT INTO table1 VALUES('It's a happy day!'); 2160** </pre></blockquote> 2161** 2162** This second example is an SQL syntax error. As a general rule you should 2163** always use %q instead of %s when inserting text into a string literal. 2164** 2165** ^(The %Q option works like %q except it also adds single quotes around 2166** the outside of the total string. Additionally, if the parameter in the 2167** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2168** single quotes).)^ So, for example, one could say: 2169** 2170** <blockquote><pre> 2171** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2172** sqlite3_exec(db, zSQL, 0, 0, 0); 2173** sqlite3_free(zSQL); 2174** </pre></blockquote> 2175** 2176** The code above will render a correct SQL statement in the zSQL 2177** variable even if the zText variable is a NULL pointer. 2178** 2179** ^(The "%z" formatting option works like "%s" but with the 2180** addition that after the string has been read and copied into 2181** the result, [sqlite3_free()] is called on the input string.)^ 2182*/ 2183char *sqlite3_mprintf(const char*,...); 2184char *sqlite3_vmprintf(const char*, va_list); 2185char *sqlite3_snprintf(int,char*,const char*, ...); 2186char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2187 2188/* 2189** CAPI3REF: Memory Allocation Subsystem 2190** 2191** The SQLite core uses these three routines for all of its own 2192** internal memory allocation needs. "Core" in the previous sentence 2193** does not include operating-system specific VFS implementation. The 2194** Windows VFS uses native malloc() and free() for some operations. 2195** 2196** ^The sqlite3_malloc() routine returns a pointer to a block 2197** of memory at least N bytes in length, where N is the parameter. 2198** ^If sqlite3_malloc() is unable to obtain sufficient free 2199** memory, it returns a NULL pointer. ^If the parameter N to 2200** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2201** a NULL pointer. 2202** 2203** ^Calling sqlite3_free() with a pointer previously returned 2204** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2205** that it might be reused. ^The sqlite3_free() routine is 2206** a no-op if is called with a NULL pointer. Passing a NULL pointer 2207** to sqlite3_free() is harmless. After being freed, memory 2208** should neither be read nor written. Even reading previously freed 2209** memory might result in a segmentation fault or other severe error. 2210** Memory corruption, a segmentation fault, or other severe error 2211** might result if sqlite3_free() is called with a non-NULL pointer that 2212** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2213** 2214** ^(The sqlite3_realloc() interface attempts to resize a 2215** prior memory allocation to be at least N bytes, where N is the 2216** second parameter. The memory allocation to be resized is the first 2217** parameter.)^ ^ If the first parameter to sqlite3_realloc() 2218** is a NULL pointer then its behavior is identical to calling 2219** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 2220** ^If the second parameter to sqlite3_realloc() is zero or 2221** negative then the behavior is exactly the same as calling 2222** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 2223** ^sqlite3_realloc() returns a pointer to a memory allocation 2224** of at least N bytes in size or NULL if sufficient memory is unavailable. 2225** ^If M is the size of the prior allocation, then min(N,M) bytes 2226** of the prior allocation are copied into the beginning of buffer returned 2227** by sqlite3_realloc() and the prior allocation is freed. 2228** ^If sqlite3_realloc() returns NULL, then the prior allocation 2229** is not freed. 2230** 2231** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 2232** is always aligned to at least an 8 byte boundary, or to a 2233** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2234** option is used. 2235** 2236** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2237** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2238** implementation of these routines to be omitted. That capability 2239** is no longer provided. Only built-in memory allocators can be used. 2240** 2241** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2242** the system malloc() and free() directly when converting 2243** filenames between the UTF-8 encoding used by SQLite 2244** and whatever filename encoding is used by the particular Windows 2245** installation. Memory allocation errors were detected, but 2246** they were reported back as [SQLITE_CANTOPEN] or 2247** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2248** 2249** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2250** must be either NULL or else pointers obtained from a prior 2251** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2252** not yet been released. 2253** 2254** The application must not read or write any part of 2255** a block of memory after it has been released using 2256** [sqlite3_free()] or [sqlite3_realloc()]. 2257*/ 2258void *sqlite3_malloc(int); 2259void *sqlite3_realloc(void*, int); 2260void sqlite3_free(void*); 2261 2262/* 2263** CAPI3REF: Memory Allocator Statistics 2264** 2265** SQLite provides these two interfaces for reporting on the status 2266** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2267** routines, which form the built-in memory allocation subsystem. 2268** 2269** ^The [sqlite3_memory_used()] routine returns the number of bytes 2270** of memory currently outstanding (malloced but not freed). 2271** ^The [sqlite3_memory_highwater()] routine returns the maximum 2272** value of [sqlite3_memory_used()] since the high-water mark 2273** was last reset. ^The values returned by [sqlite3_memory_used()] and 2274** [sqlite3_memory_highwater()] include any overhead 2275** added by SQLite in its implementation of [sqlite3_malloc()], 2276** but not overhead added by the any underlying system library 2277** routines that [sqlite3_malloc()] may call. 2278** 2279** ^The memory high-water mark is reset to the current value of 2280** [sqlite3_memory_used()] if and only if the parameter to 2281** [sqlite3_memory_highwater()] is true. ^The value returned 2282** by [sqlite3_memory_highwater(1)] is the high-water mark 2283** prior to the reset. 2284*/ 2285sqlite3_int64 sqlite3_memory_used(void); 2286sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2287 2288/* 2289** CAPI3REF: Pseudo-Random Number Generator 2290** 2291** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2292** select random [ROWID | ROWIDs] when inserting new records into a table that 2293** already uses the largest possible [ROWID]. The PRNG is also used for 2294** the build-in random() and randomblob() SQL functions. This interface allows 2295** applications to access the same PRNG for other purposes. 2296** 2297** ^A call to this routine stores N bytes of randomness into buffer P. 2298** 2299** ^The first time this routine is invoked (either internally or by 2300** the application) the PRNG is seeded using randomness obtained 2301** from the xRandomness method of the default [sqlite3_vfs] object. 2302** ^On all subsequent invocations, the pseudo-randomness is generated 2303** internally and without recourse to the [sqlite3_vfs] xRandomness 2304** method. 2305*/ 2306void sqlite3_randomness(int N, void *P); 2307 2308/* 2309** CAPI3REF: Compile-Time Authorization Callbacks 2310** 2311** ^This routine registers an authorizer callback with a particular 2312** [database connection], supplied in the first argument. 2313** ^The authorizer callback is invoked as SQL statements are being compiled 2314** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2315** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2316** points during the compilation process, as logic is being created 2317** to perform various actions, the authorizer callback is invoked to 2318** see if those actions are allowed. ^The authorizer callback should 2319** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2320** specific action but allow the SQL statement to continue to be 2321** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2322** rejected with an error. ^If the authorizer callback returns 2323** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2324** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2325** the authorizer will fail with an error message. 2326** 2327** When the callback returns [SQLITE_OK], that means the operation 2328** requested is ok. ^When the callback returns [SQLITE_DENY], the 2329** [sqlite3_prepare_v2()] or equivalent call that triggered the 2330** authorizer will fail with an error message explaining that 2331** access is denied. 2332** 2333** ^The first parameter to the authorizer callback is a copy of the third 2334** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2335** to the callback is an integer [SQLITE_COPY | action code] that specifies 2336** the particular action to be authorized. ^The third through sixth parameters 2337** to the callback are zero-terminated strings that contain additional 2338** details about the action to be authorized. 2339** 2340** ^If the action code is [SQLITE_READ] 2341** and the callback returns [SQLITE_IGNORE] then the 2342** [prepared statement] statement is constructed to substitute 2343** a NULL value in place of the table column that would have 2344** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2345** return can be used to deny an untrusted user access to individual 2346** columns of a table. 2347** ^If the action code is [SQLITE_DELETE] and the callback returns 2348** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2349** [truncate optimization] is disabled and all rows are deleted individually. 2350** 2351** An authorizer is used when [sqlite3_prepare | preparing] 2352** SQL statements from an untrusted source, to ensure that the SQL statements 2353** do not try to access data they are not allowed to see, or that they do not 2354** try to execute malicious statements that damage the database. For 2355** example, an application may allow a user to enter arbitrary 2356** SQL queries for evaluation by a database. But the application does 2357** not want the user to be able to make arbitrary changes to the 2358** database. An authorizer could then be put in place while the 2359** user-entered SQL is being [sqlite3_prepare | prepared] that 2360** disallows everything except [SELECT] statements. 2361** 2362** Applications that need to process SQL from untrusted sources 2363** might also consider lowering resource limits using [sqlite3_limit()] 2364** and limiting database size using the [max_page_count] [PRAGMA] 2365** in addition to using an authorizer. 2366** 2367** ^(Only a single authorizer can be in place on a database connection 2368** at a time. Each call to sqlite3_set_authorizer overrides the 2369** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2370** The authorizer is disabled by default. 2371** 2372** The authorizer callback must not do anything that will modify 2373** the database connection that invoked the authorizer callback. 2374** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2375** database connections for the meaning of "modify" in this paragraph. 2376** 2377** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2378** statement might be re-prepared during [sqlite3_step()] due to a 2379** schema change. Hence, the application should ensure that the 2380** correct authorizer callback remains in place during the [sqlite3_step()]. 2381** 2382** ^Note that the authorizer callback is invoked only during 2383** [sqlite3_prepare()] or its variants. Authorization is not 2384** performed during statement evaluation in [sqlite3_step()], unless 2385** as stated in the previous paragraph, sqlite3_step() invokes 2386** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2387*/ 2388int sqlite3_set_authorizer( 2389 sqlite3*, 2390 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2391 void *pUserData 2392); 2393 2394/* 2395** CAPI3REF: Authorizer Return Codes 2396** 2397** The [sqlite3_set_authorizer | authorizer callback function] must 2398** return either [SQLITE_OK] or one of these two constants in order 2399** to signal SQLite whether or not the action is permitted. See the 2400** [sqlite3_set_authorizer | authorizer documentation] for additional 2401** information. 2402** 2403** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code] 2404** from the [sqlite3_vtab_on_conflict()] interface. 2405*/ 2406#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2407#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2408 2409/* 2410** CAPI3REF: Authorizer Action Codes 2411** 2412** The [sqlite3_set_authorizer()] interface registers a callback function 2413** that is invoked to authorize certain SQL statement actions. The 2414** second parameter to the callback is an integer code that specifies 2415** what action is being authorized. These are the integer action codes that 2416** the authorizer callback may be passed. 2417** 2418** These action code values signify what kind of operation is to be 2419** authorized. The 3rd and 4th parameters to the authorization 2420** callback function will be parameters or NULL depending on which of these 2421** codes is used as the second parameter. ^(The 5th parameter to the 2422** authorizer callback is the name of the database ("main", "temp", 2423** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2424** is the name of the inner-most trigger or view that is responsible for 2425** the access attempt or NULL if this access attempt is directly from 2426** top-level SQL code. 2427*/ 2428/******************************************* 3rd ************ 4th ***********/ 2429#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2430#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2431#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2432#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2433#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2434#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2435#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2436#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2437#define SQLITE_DELETE 9 /* Table Name NULL */ 2438#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2439#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2440#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2441#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2442#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2443#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2444#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2445#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2446#define SQLITE_INSERT 18 /* Table Name NULL */ 2447#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2448#define SQLITE_READ 20 /* Table Name Column Name */ 2449#define SQLITE_SELECT 21 /* NULL NULL */ 2450#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2451#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2452#define SQLITE_ATTACH 24 /* Filename NULL */ 2453#define SQLITE_DETACH 25 /* Database Name NULL */ 2454#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2455#define SQLITE_REINDEX 27 /* Index Name NULL */ 2456#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2457#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2458#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2459#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2460#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2461#define SQLITE_COPY 0 /* No longer used */ 2462 2463/* 2464** CAPI3REF: Tracing And Profiling Functions 2465** 2466** These routines register callback functions that can be used for 2467** tracing and profiling the execution of SQL statements. 2468** 2469** ^The callback function registered by sqlite3_trace() is invoked at 2470** various times when an SQL statement is being run by [sqlite3_step()]. 2471** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2472** SQL statement text as the statement first begins executing. 2473** ^(Additional sqlite3_trace() callbacks might occur 2474** as each triggered subprogram is entered. The callbacks for triggers 2475** contain a UTF-8 SQL comment that identifies the trigger.)^ 2476** 2477** ^The callback function registered by sqlite3_profile() is invoked 2478** as each SQL statement finishes. ^The profile callback contains 2479** the original statement text and an estimate of wall-clock time 2480** of how long that statement took to run. ^The profile callback 2481** time is in units of nanoseconds, however the current implementation 2482** is only capable of millisecond resolution so the six least significant 2483** digits in the time are meaningless. Future versions of SQLite 2484** might provide greater resolution on the profiler callback. The 2485** sqlite3_profile() function is considered experimental and is 2486** subject to change in future versions of SQLite. 2487*/ 2488void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2489SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2490 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2491 2492/* 2493** CAPI3REF: Query Progress Callbacks 2494** 2495** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2496** function X to be invoked periodically during long running calls to 2497** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2498** database connection D. An example use for this 2499** interface is to keep a GUI updated during a large query. 2500** 2501** ^The parameter P is passed through as the only parameter to the 2502** callback function X. ^The parameter N is the number of 2503** [virtual machine instructions] that are evaluated between successive 2504** invocations of the callback X. 2505** 2506** ^Only a single progress handler may be defined at one time per 2507** [database connection]; setting a new progress handler cancels the 2508** old one. ^Setting parameter X to NULL disables the progress handler. 2509** ^The progress handler is also disabled by setting N to a value less 2510** than 1. 2511** 2512** ^If the progress callback returns non-zero, the operation is 2513** interrupted. This feature can be used to implement a 2514** "Cancel" button on a GUI progress dialog box. 2515** 2516** The progress handler callback must not do anything that will modify 2517** the database connection that invoked the progress handler. 2518** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2519** database connections for the meaning of "modify" in this paragraph. 2520** 2521*/ 2522void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2523 2524/* 2525** CAPI3REF: Opening A New Database Connection 2526** 2527** ^These routines open an SQLite database file as specified by the 2528** filename argument. ^The filename argument is interpreted as UTF-8 for 2529** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2530** order for sqlite3_open16(). ^(A [database connection] handle is usually 2531** returned in *ppDb, even if an error occurs. The only exception is that 2532** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2533** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2534** object.)^ ^(If the database is opened (and/or created) successfully, then 2535** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2536** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2537** an English language description of the error following a failure of any 2538** of the sqlite3_open() routines. 2539** 2540** ^The default encoding for the database will be UTF-8 if 2541** sqlite3_open() or sqlite3_open_v2() is called and 2542** UTF-16 in the native byte order if sqlite3_open16() is used. 2543** 2544** Whether or not an error occurs when it is opened, resources 2545** associated with the [database connection] handle should be released by 2546** passing it to [sqlite3_close()] when it is no longer required. 2547** 2548** The sqlite3_open_v2() interface works like sqlite3_open() 2549** except that it accepts two additional parameters for additional control 2550** over the new database connection. ^(The flags parameter to 2551** sqlite3_open_v2() can take one of 2552** the following three values, optionally combined with the 2553** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2554** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2555** 2556** <dl> 2557** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2558** <dd>The database is opened in read-only mode. If the database does not 2559** already exist, an error is returned.</dd>)^ 2560** 2561** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2562** <dd>The database is opened for reading and writing if possible, or reading 2563** only if the file is write protected by the operating system. In either 2564** case the database must already exist, otherwise an error is returned.</dd>)^ 2565** 2566** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2567** <dd>The database is opened for reading and writing, and is created if 2568** it does not already exist. This is the behavior that is always used for 2569** sqlite3_open() and sqlite3_open16().</dd>)^ 2570** </dl> 2571** 2572** If the 3rd parameter to sqlite3_open_v2() is not one of the 2573** combinations shown above optionally combined with other 2574** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2575** then the behavior is undefined. 2576** 2577** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2578** opens in the multi-thread [threading mode] as long as the single-thread 2579** mode has not been set at compile-time or start-time. ^If the 2580** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2581** in the serialized [threading mode] unless single-thread was 2582** previously selected at compile-time or start-time. 2583** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2584** eligible to use [shared cache mode], regardless of whether or not shared 2585** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2586** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2587** participate in [shared cache mode] even if it is enabled. 2588** 2589** ^The fourth parameter to sqlite3_open_v2() is the name of the 2590** [sqlite3_vfs] object that defines the operating system interface that 2591** the new database connection should use. ^If the fourth parameter is 2592** a NULL pointer then the default [sqlite3_vfs] object is used. 2593** 2594** ^If the filename is ":memory:", then a private, temporary in-memory database 2595** is created for the connection. ^This in-memory database will vanish when 2596** the database connection is closed. Future versions of SQLite might 2597** make use of additional special filenames that begin with the ":" character. 2598** It is recommended that when a database filename actually does begin with 2599** a ":" character you should prefix the filename with a pathname such as 2600** "./" to avoid ambiguity. 2601** 2602** ^If the filename is an empty string, then a private, temporary 2603** on-disk database will be created. ^This private database will be 2604** automatically deleted as soon as the database connection is closed. 2605** 2606** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2607** 2608** ^If [URI filename] interpretation is enabled, and the filename argument 2609** begins with "file:", then the filename is interpreted as a URI. ^URI 2610** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2611** set in the fourth argument to sqlite3_open_v2(), or if it has 2612** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2613** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2614** As of SQLite version 3.7.7, URI filename interpretation is turned off 2615** by default, but future releases of SQLite might enable URI filename 2616** interpretation by default. See "[URI filenames]" for additional 2617** information. 2618** 2619** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2620** authority, then it must be either an empty string or the string 2621** "localhost". ^If the authority is not an empty string or "localhost", an 2622** error is returned to the caller. ^The fragment component of a URI, if 2623** present, is ignored. 2624** 2625** ^SQLite uses the path component of the URI as the name of the disk file 2626** which contains the database. ^If the path begins with a '/' character, 2627** then it is interpreted as an absolute path. ^If the path does not begin 2628** with a '/' (meaning that the authority section is omitted from the URI) 2629** then the path is interpreted as a relative path. 2630** ^On windows, the first component of an absolute path 2631** is a drive specification (e.g. "C:"). 2632** 2633** [[core URI query parameters]] 2634** The query component of a URI may contain parameters that are interpreted 2635** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2636** SQLite interprets the following three query parameters: 2637** 2638** <ul> 2639** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2640** a VFS object that provides the operating system interface that should 2641** be used to access the database file on disk. ^If this option is set to 2642** an empty string the default VFS object is used. ^Specifying an unknown 2643** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2644** present, then the VFS specified by the option takes precedence over 2645** the value passed as the fourth parameter to sqlite3_open_v2(). 2646** 2647** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 2648** "rwc", or "memory". Attempting to set it to any other value is 2649** an error)^. 2650** ^If "ro" is specified, then the database is opened for read-only 2651** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2652** third argument to sqlite3_open_v2(). ^If the mode option is set to 2653** "rw", then the database is opened for read-write (but not create) 2654** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2655** been set. ^Value "rwc" is equivalent to setting both 2656** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 2657** set to "memory" then a pure [in-memory database] that never reads 2658** or writes from disk is used. ^It is an error to specify a value for 2659** the mode parameter that is less restrictive than that specified by 2660** the flags passed in the third parameter to sqlite3_open_v2(). 2661** 2662** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2663** "private". ^Setting it to "shared" is equivalent to setting the 2664** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2665** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2666** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2667** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2668** a URI filename, its value overrides any behaviour requested by setting 2669** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2670** </ul> 2671** 2672** ^Specifying an unknown parameter in the query component of a URI is not an 2673** error. Future versions of SQLite might understand additional query 2674** parameters. See "[query parameters with special meaning to SQLite]" for 2675** additional information. 2676** 2677** [[URI filename examples]] <h3>URI filename examples</h3> 2678** 2679** <table border="1" align=center cellpadding=5> 2680** <tr><th> URI filenames <th> Results 2681** <tr><td> file:data.db <td> 2682** Open the file "data.db" in the current directory. 2683** <tr><td> file:/home/fred/data.db<br> 2684** file:///home/fred/data.db <br> 2685** file://localhost/home/fred/data.db <br> <td> 2686** Open the database file "/home/fred/data.db". 2687** <tr><td> file://darkstar/home/fred/data.db <td> 2688** An error. "darkstar" is not a recognized authority. 2689** <tr><td style="white-space:nowrap"> 2690** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2691** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2692** C:. Note that the %20 escaping in this example is not strictly 2693** necessary - space characters can be used literally 2694** in URI filenames. 2695** <tr><td> file:data.db?mode=ro&cache=private <td> 2696** Open file "data.db" in the current directory for read-only access. 2697** Regardless of whether or not shared-cache mode is enabled by 2698** default, use a private cache. 2699** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td> 2700** Open file "/home/fred/data.db". Use the special VFS "unix-nolock". 2701** <tr><td> file:data.db?mode=readonly <td> 2702** An error. "readonly" is not a valid option for the "mode" parameter. 2703** </table> 2704** 2705** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2706** query components of a URI. A hexadecimal escape sequence consists of a 2707** percent sign - "%" - followed by exactly two hexadecimal digits 2708** specifying an octet value. ^Before the path or query components of a 2709** URI filename are interpreted, they are encoded using UTF-8 and all 2710** hexadecimal escape sequences replaced by a single byte containing the 2711** corresponding octet. If this process generates an invalid UTF-8 encoding, 2712** the results are undefined. 2713** 2714** <b>Note to Windows users:</b> The encoding used for the filename argument 2715** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2716** codepage is currently defined. Filenames containing international 2717** characters must be converted to UTF-8 prior to passing them into 2718** sqlite3_open() or sqlite3_open_v2(). 2719** 2720** <b>Note to Windows Runtime users:</b> The temporary directory must be set 2721** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 2722** features that require the use of temporary files may fail. 2723** 2724** See also: [sqlite3_temp_directory] 2725*/ 2726int sqlite3_open( 2727 const char *filename, /* Database filename (UTF-8) */ 2728 sqlite3 **ppDb /* OUT: SQLite db handle */ 2729); 2730int sqlite3_open16( 2731 const void *filename, /* Database filename (UTF-16) */ 2732 sqlite3 **ppDb /* OUT: SQLite db handle */ 2733); 2734int sqlite3_open_v2( 2735 const char *filename, /* Database filename (UTF-8) */ 2736 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2737 int flags, /* Flags */ 2738 const char *zVfs /* Name of VFS module to use */ 2739); 2740 2741/* 2742** CAPI3REF: Obtain Values For URI Parameters 2743** 2744** These are utility routines, useful to VFS implementations, that check 2745** to see if a database file was a URI that contained a specific query 2746** parameter, and if so obtains the value of that query parameter. 2747** 2748** If F is the database filename pointer passed into the xOpen() method of 2749** a VFS implementation when the flags parameter to xOpen() has one or 2750** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 2751** P is the name of the query parameter, then 2752** sqlite3_uri_parameter(F,P) returns the value of the P 2753** parameter if it exists or a NULL pointer if P does not appear as a 2754** query parameter on F. If P is a query parameter of F 2755** has no explicit value, then sqlite3_uri_parameter(F,P) returns 2756** a pointer to an empty string. 2757** 2758** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 2759** parameter and returns true (1) or false (0) according to the value 2760** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 2761** value of query parameter P is one of "yes", "true", or "on" in any 2762** case or if the value begins with a non-zero number. The 2763** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 2764** query parameter P is one of "no", "false", or "off" in any case or 2765** if the value begins with a numeric zero. If P is not a query 2766** parameter on F or if the value of P is does not match any of the 2767** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 2768** 2769** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 2770** 64-bit signed integer and returns that integer, or D if P does not 2771** exist. If the value of P is something other than an integer, then 2772** zero is returned. 2773** 2774** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 2775** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 2776** is not a database file pathname pointer that SQLite passed into the xOpen 2777** VFS method, then the behavior of this routine is undefined and probably 2778** undesirable. 2779*/ 2780const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 2781int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 2782sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 2783 2784 2785/* 2786** CAPI3REF: Error Codes And Messages 2787** 2788** ^The sqlite3_errcode() interface returns the numeric [result code] or 2789** [extended result code] for the most recent failed sqlite3_* API call 2790** associated with a [database connection]. If a prior API call failed 2791** but the most recent API call succeeded, the return value from 2792** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2793** interface is the same except that it always returns the 2794** [extended result code] even when extended result codes are 2795** disabled. 2796** 2797** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2798** text that describes the error, as either UTF-8 or UTF-16 respectively. 2799** ^(Memory to hold the error message string is managed internally. 2800** The application does not need to worry about freeing the result. 2801** However, the error string might be overwritten or deallocated by 2802** subsequent calls to other SQLite interface functions.)^ 2803** 2804** ^The sqlite3_errstr() interface returns the English-language text 2805** that describes the [result code], as UTF-8. 2806** ^(Memory to hold the error message string is managed internally 2807** and must not be freed by the application)^. 2808** 2809** When the serialized [threading mode] is in use, it might be the 2810** case that a second error occurs on a separate thread in between 2811** the time of the first error and the call to these interfaces. 2812** When that happens, the second error will be reported since these 2813** interfaces always report the most recent result. To avoid 2814** this, each thread can obtain exclusive use of the [database connection] D 2815** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2816** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2817** all calls to the interfaces listed here are completed. 2818** 2819** If an interface fails with SQLITE_MISUSE, that means the interface 2820** was invoked incorrectly by the application. In that case, the 2821** error code and message may or may not be set. 2822*/ 2823int sqlite3_errcode(sqlite3 *db); 2824int sqlite3_extended_errcode(sqlite3 *db); 2825const char *sqlite3_errmsg(sqlite3*); 2826const void *sqlite3_errmsg16(sqlite3*); 2827const char *sqlite3_errstr(int); 2828 2829/* 2830** CAPI3REF: SQL Statement Object 2831** KEYWORDS: {prepared statement} {prepared statements} 2832** 2833** An instance of this object represents a single SQL statement. 2834** This object is variously known as a "prepared statement" or a 2835** "compiled SQL statement" or simply as a "statement". 2836** 2837** The life of a statement object goes something like this: 2838** 2839** <ol> 2840** <li> Create the object using [sqlite3_prepare_v2()] or a related 2841** function. 2842** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2843** interfaces. 2844** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2845** <li> Reset the statement using [sqlite3_reset()] then go back 2846** to step 2. Do this zero or more times. 2847** <li> Destroy the object using [sqlite3_finalize()]. 2848** </ol> 2849** 2850** Refer to documentation on individual methods above for additional 2851** information. 2852*/ 2853typedef struct sqlite3_stmt sqlite3_stmt; 2854 2855/* 2856** CAPI3REF: Run-time Limits 2857** 2858** ^(This interface allows the size of various constructs to be limited 2859** on a connection by connection basis. The first parameter is the 2860** [database connection] whose limit is to be set or queried. The 2861** second parameter is one of the [limit categories] that define a 2862** class of constructs to be size limited. The third parameter is the 2863** new limit for that construct.)^ 2864** 2865** ^If the new limit is a negative number, the limit is unchanged. 2866** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 2867** [limits | hard upper bound] 2868** set at compile-time by a C preprocessor macro called 2869** [limits | SQLITE_MAX_<i>NAME</i>]. 2870** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2871** ^Attempts to increase a limit above its hard upper bound are 2872** silently truncated to the hard upper bound. 2873** 2874** ^Regardless of whether or not the limit was changed, the 2875** [sqlite3_limit()] interface returns the prior value of the limit. 2876** ^Hence, to find the current value of a limit without changing it, 2877** simply invoke this interface with the third parameter set to -1. 2878** 2879** Run-time limits are intended for use in applications that manage 2880** both their own internal database and also databases that are controlled 2881** by untrusted external sources. An example application might be a 2882** web browser that has its own databases for storing history and 2883** separate databases controlled by JavaScript applications downloaded 2884** off the Internet. The internal databases can be given the 2885** large, default limits. Databases managed by external sources can 2886** be given much smaller limits designed to prevent a denial of service 2887** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2888** interface to further control untrusted SQL. The size of the database 2889** created by an untrusted script can be contained using the 2890** [max_page_count] [PRAGMA]. 2891** 2892** New run-time limit categories may be added in future releases. 2893*/ 2894int sqlite3_limit(sqlite3*, int id, int newVal); 2895 2896/* 2897** CAPI3REF: Run-Time Limit Categories 2898** KEYWORDS: {limit category} {*limit categories} 2899** 2900** These constants define various performance limits 2901** that can be lowered at run-time using [sqlite3_limit()]. 2902** The synopsis of the meanings of the various limits is shown below. 2903** Additional information is available at [limits | Limits in SQLite]. 2904** 2905** <dl> 2906** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2907** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 2908** 2909** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2910** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2911** 2912** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2913** <dd>The maximum number of columns in a table definition or in the 2914** result set of a [SELECT] or the maximum number of columns in an index 2915** or in an ORDER BY or GROUP BY clause.</dd>)^ 2916** 2917** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2918** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2919** 2920** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2921** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2922** 2923** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2924** <dd>The maximum number of instructions in a virtual machine program 2925** used to implement an SQL statement. This limit is not currently 2926** enforced, though that might be added in some future release of 2927** SQLite.</dd>)^ 2928** 2929** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2930** <dd>The maximum number of arguments on a function.</dd>)^ 2931** 2932** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2933** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2934** 2935** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 2936** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2937** <dd>The maximum length of the pattern argument to the [LIKE] or 2938** [GLOB] operators.</dd>)^ 2939** 2940** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 2941** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2942** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 2943** 2944** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2945** <dd>The maximum depth of recursion for triggers.</dd>)^ 2946** </dl> 2947*/ 2948#define SQLITE_LIMIT_LENGTH 0 2949#define SQLITE_LIMIT_SQL_LENGTH 1 2950#define SQLITE_LIMIT_COLUMN 2 2951#define SQLITE_LIMIT_EXPR_DEPTH 3 2952#define SQLITE_LIMIT_COMPOUND_SELECT 4 2953#define SQLITE_LIMIT_VDBE_OP 5 2954#define SQLITE_LIMIT_FUNCTION_ARG 6 2955#define SQLITE_LIMIT_ATTACHED 7 2956#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2957#define SQLITE_LIMIT_VARIABLE_NUMBER 9 2958#define SQLITE_LIMIT_TRIGGER_DEPTH 10 2959 2960/* 2961** CAPI3REF: Compiling An SQL Statement 2962** KEYWORDS: {SQL statement compiler} 2963** 2964** To execute an SQL query, it must first be compiled into a byte-code 2965** program using one of these routines. 2966** 2967** The first argument, "db", is a [database connection] obtained from a 2968** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2969** [sqlite3_open16()]. The database connection must not have been closed. 2970** 2971** The second argument, "zSql", is the statement to be compiled, encoded 2972** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2973** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2974** use UTF-16. 2975** 2976** ^If the nByte argument is less than zero, then zSql is read up to the 2977** first zero terminator. ^If nByte is non-negative, then it is the maximum 2978** number of bytes read from zSql. ^When nByte is non-negative, the 2979** zSql string ends at either the first '\000' or '\u0000' character or 2980** the nByte-th byte, whichever comes first. If the caller knows 2981** that the supplied string is nul-terminated, then there is a small 2982** performance advantage to be gained by passing an nByte parameter that 2983** is equal to the number of bytes in the input string <i>including</i> 2984** the nul-terminator bytes as this saves SQLite from having to 2985** make a copy of the input string. 2986** 2987** ^If pzTail is not NULL then *pzTail is made to point to the first byte 2988** past the end of the first SQL statement in zSql. These routines only 2989** compile the first statement in zSql, so *pzTail is left pointing to 2990** what remains uncompiled. 2991** 2992** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 2993** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 2994** to NULL. ^If the input text contains no SQL (if the input is an empty 2995** string or a comment) then *ppStmt is set to NULL. 2996** The calling procedure is responsible for deleting the compiled 2997** SQL statement using [sqlite3_finalize()] after it has finished with it. 2998** ppStmt may not be NULL. 2999** 3000** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3001** otherwise an [error code] is returned. 3002** 3003** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 3004** recommended for all new programs. The two older interfaces are retained 3005** for backwards compatibility, but their use is discouraged. 3006** ^In the "v2" interfaces, the prepared statement 3007** that is returned (the [sqlite3_stmt] object) contains a copy of the 3008** original SQL text. This causes the [sqlite3_step()] interface to 3009** behave differently in three ways: 3010** 3011** <ol> 3012** <li> 3013** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3014** always used to do, [sqlite3_step()] will automatically recompile the SQL 3015** statement and try to run it again. 3016** </li> 3017** 3018** <li> 3019** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3020** [error codes] or [extended error codes]. ^The legacy behavior was that 3021** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3022** and the application would have to make a second call to [sqlite3_reset()] 3023** in order to find the underlying cause of the problem. With the "v2" prepare 3024** interfaces, the underlying reason for the error is returned immediately. 3025** </li> 3026** 3027** <li> 3028** ^If the specific value bound to [parameter | host parameter] in the 3029** WHERE clause might influence the choice of query plan for a statement, 3030** then the statement will be automatically recompiled, as if there had been 3031** a schema change, on the first [sqlite3_step()] call following any change 3032** to the [sqlite3_bind_text | bindings] of that [parameter]. 3033** ^The specific value of WHERE-clause [parameter] might influence the 3034** choice of query plan if the parameter is the left-hand side of a [LIKE] 3035** or [GLOB] operator or if the parameter is compared to an indexed column 3036** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3037** the 3038** </li> 3039** </ol> 3040*/ 3041int sqlite3_prepare( 3042 sqlite3 *db, /* Database handle */ 3043 const char *zSql, /* SQL statement, UTF-8 encoded */ 3044 int nByte, /* Maximum length of zSql in bytes. */ 3045 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3046 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3047); 3048int sqlite3_prepare_v2( 3049 sqlite3 *db, /* Database handle */ 3050 const char *zSql, /* SQL statement, UTF-8 encoded */ 3051 int nByte, /* Maximum length of zSql in bytes. */ 3052 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3053 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3054); 3055int sqlite3_prepare16( 3056 sqlite3 *db, /* Database handle */ 3057 const void *zSql, /* SQL statement, UTF-16 encoded */ 3058 int nByte, /* Maximum length of zSql in bytes. */ 3059 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3060 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3061); 3062int sqlite3_prepare16_v2( 3063 sqlite3 *db, /* Database handle */ 3064 const void *zSql, /* SQL statement, UTF-16 encoded */ 3065 int nByte, /* Maximum length of zSql in bytes. */ 3066 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3067 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3068); 3069 3070/* 3071** CAPI3REF: Retrieving Statement SQL 3072** 3073** ^This interface can be used to retrieve a saved copy of the original 3074** SQL text used to create a [prepared statement] if that statement was 3075** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 3076*/ 3077const char *sqlite3_sql(sqlite3_stmt *pStmt); 3078 3079/* 3080** CAPI3REF: Determine If An SQL Statement Writes The Database 3081** 3082** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3083** and only if the [prepared statement] X makes no direct changes to 3084** the content of the database file. 3085** 3086** Note that [application-defined SQL functions] or 3087** [virtual tables] might change the database indirectly as a side effect. 3088** ^(For example, if an application defines a function "eval()" that 3089** calls [sqlite3_exec()], then the following SQL statement would 3090** change the database file through side-effects: 3091** 3092** <blockquote><pre> 3093** SELECT eval('DELETE FROM t1') FROM t2; 3094** </pre></blockquote> 3095** 3096** But because the [SELECT] statement does not change the database file 3097** directly, sqlite3_stmt_readonly() would still return true.)^ 3098** 3099** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3100** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3101** since the statements themselves do not actually modify the database but 3102** rather they control the timing of when other statements modify the 3103** database. ^The [ATTACH] and [DETACH] statements also cause 3104** sqlite3_stmt_readonly() to return true since, while those statements 3105** change the configuration of a database connection, they do not make 3106** changes to the content of the database files on disk. 3107*/ 3108int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3109 3110/* 3111** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3112** 3113** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3114** [prepared statement] S has been stepped at least once using 3115** [sqlite3_step(S)] but has not run to completion and/or has not 3116** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3117** interface returns false if S is a NULL pointer. If S is not a 3118** NULL pointer and is not a pointer to a valid [prepared statement] 3119** object, then the behavior is undefined and probably undesirable. 3120** 3121** This interface can be used in combination [sqlite3_next_stmt()] 3122** to locate all prepared statements associated with a database 3123** connection that are in need of being reset. This can be used, 3124** for example, in diagnostic routines to search for prepared 3125** statements that are holding a transaction open. 3126*/ 3127int sqlite3_stmt_busy(sqlite3_stmt*); 3128 3129/* 3130** CAPI3REF: Dynamically Typed Value Object 3131** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3132** 3133** SQLite uses the sqlite3_value object to represent all values 3134** that can be stored in a database table. SQLite uses dynamic typing 3135** for the values it stores. ^Values stored in sqlite3_value objects 3136** can be integers, floating point values, strings, BLOBs, or NULL. 3137** 3138** An sqlite3_value object may be either "protected" or "unprotected". 3139** Some interfaces require a protected sqlite3_value. Other interfaces 3140** will accept either a protected or an unprotected sqlite3_value. 3141** Every interface that accepts sqlite3_value arguments specifies 3142** whether or not it requires a protected sqlite3_value. 3143** 3144** The terms "protected" and "unprotected" refer to whether or not 3145** a mutex is held. An internal mutex is held for a protected 3146** sqlite3_value object but no mutex is held for an unprotected 3147** sqlite3_value object. If SQLite is compiled to be single-threaded 3148** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3149** or if SQLite is run in one of reduced mutex modes 3150** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3151** then there is no distinction between protected and unprotected 3152** sqlite3_value objects and they can be used interchangeably. However, 3153** for maximum code portability it is recommended that applications 3154** still make the distinction between protected and unprotected 3155** sqlite3_value objects even when not strictly required. 3156** 3157** ^The sqlite3_value objects that are passed as parameters into the 3158** implementation of [application-defined SQL functions] are protected. 3159** ^The sqlite3_value object returned by 3160** [sqlite3_column_value()] is unprotected. 3161** Unprotected sqlite3_value objects may only be used with 3162** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3163** The [sqlite3_value_blob | sqlite3_value_type()] family of 3164** interfaces require protected sqlite3_value objects. 3165*/ 3166typedef struct Mem sqlite3_value; 3167 3168/* 3169** CAPI3REF: SQL Function Context Object 3170** 3171** The context in which an SQL function executes is stored in an 3172** sqlite3_context object. ^A pointer to an sqlite3_context object 3173** is always first parameter to [application-defined SQL functions]. 3174** The application-defined SQL function implementation will pass this 3175** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3176** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3177** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3178** and/or [sqlite3_set_auxdata()]. 3179*/ 3180typedef struct sqlite3_context sqlite3_context; 3181 3182/* 3183** CAPI3REF: Binding Values To Prepared Statements 3184** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3185** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3186** 3187** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3188** literals may be replaced by a [parameter] that matches one of following 3189** templates: 3190** 3191** <ul> 3192** <li> ? 3193** <li> ?NNN 3194** <li> :VVV 3195** <li> @VVV 3196** <li> $VVV 3197** </ul> 3198** 3199** In the templates above, NNN represents an integer literal, 3200** and VVV represents an alphanumeric identifier.)^ ^The values of these 3201** parameters (also called "host parameter names" or "SQL parameters") 3202** can be set using the sqlite3_bind_*() routines defined here. 3203** 3204** ^The first argument to the sqlite3_bind_*() routines is always 3205** a pointer to the [sqlite3_stmt] object returned from 3206** [sqlite3_prepare_v2()] or its variants. 3207** 3208** ^The second argument is the index of the SQL parameter to be set. 3209** ^The leftmost SQL parameter has an index of 1. ^When the same named 3210** SQL parameter is used more than once, second and subsequent 3211** occurrences have the same index as the first occurrence. 3212** ^The index for named parameters can be looked up using the 3213** [sqlite3_bind_parameter_index()] API if desired. ^The index 3214** for "?NNN" parameters is the value of NNN. 3215** ^The NNN value must be between 1 and the [sqlite3_limit()] 3216** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3217** 3218** ^The third argument is the value to bind to the parameter. 3219** 3220** ^(In those routines that have a fourth argument, its value is the 3221** number of bytes in the parameter. To be clear: the value is the 3222** number of <u>bytes</u> in the value, not the number of characters.)^ 3223** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3224** is negative, then the length of the string is 3225** the number of bytes up to the first zero terminator. 3226** If the fourth parameter to sqlite3_bind_blob() is negative, then 3227** the behavior is undefined. 3228** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3229** or sqlite3_bind_text16() then that parameter must be the byte offset 3230** where the NUL terminator would occur assuming the string were NUL 3231** terminated. If any NUL characters occur at byte offsets less than 3232** the value of the fourth parameter then the resulting string value will 3233** contain embedded NULs. The result of expressions involving strings 3234** with embedded NULs is undefined. 3235** 3236** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 3237** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 3238** string after SQLite has finished with it. ^The destructor is called 3239** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(), 3240** sqlite3_bind_text(), or sqlite3_bind_text16() fails. 3241** ^If the fifth argument is 3242** the special value [SQLITE_STATIC], then SQLite assumes that the 3243** information is in static, unmanaged space and does not need to be freed. 3244** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3245** SQLite makes its own private copy of the data immediately, before 3246** the sqlite3_bind_*() routine returns. 3247** 3248** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3249** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3250** (just an integer to hold its size) while it is being processed. 3251** Zeroblobs are intended to serve as placeholders for BLOBs whose 3252** content is later written using 3253** [sqlite3_blob_open | incremental BLOB I/O] routines. 3254** ^A negative value for the zeroblob results in a zero-length BLOB. 3255** 3256** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3257** for the [prepared statement] or with a prepared statement for which 3258** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3259** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3260** routine is passed a [prepared statement] that has been finalized, the 3261** result is undefined and probably harmful. 3262** 3263** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3264** ^Unbound parameters are interpreted as NULL. 3265** 3266** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3267** [error code] if anything goes wrong. 3268** ^[SQLITE_RANGE] is returned if the parameter 3269** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3270** 3271** See also: [sqlite3_bind_parameter_count()], 3272** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3273*/ 3274int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3275int sqlite3_bind_double(sqlite3_stmt*, int, double); 3276int sqlite3_bind_int(sqlite3_stmt*, int, int); 3277int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3278int sqlite3_bind_null(sqlite3_stmt*, int); 3279int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 3280int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3281int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3282int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3283 3284/* 3285** CAPI3REF: Number Of SQL Parameters 3286** 3287** ^This routine can be used to find the number of [SQL parameters] 3288** in a [prepared statement]. SQL parameters are tokens of the 3289** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3290** placeholders for values that are [sqlite3_bind_blob | bound] 3291** to the parameters at a later time. 3292** 3293** ^(This routine actually returns the index of the largest (rightmost) 3294** parameter. For all forms except ?NNN, this will correspond to the 3295** number of unique parameters. If parameters of the ?NNN form are used, 3296** there may be gaps in the list.)^ 3297** 3298** See also: [sqlite3_bind_blob|sqlite3_bind()], 3299** [sqlite3_bind_parameter_name()], and 3300** [sqlite3_bind_parameter_index()]. 3301*/ 3302int sqlite3_bind_parameter_count(sqlite3_stmt*); 3303 3304/* 3305** CAPI3REF: Name Of A Host Parameter 3306** 3307** ^The sqlite3_bind_parameter_name(P,N) interface returns 3308** the name of the N-th [SQL parameter] in the [prepared statement] P. 3309** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3310** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3311** respectively. 3312** In other words, the initial ":" or "$" or "@" or "?" 3313** is included as part of the name.)^ 3314** ^Parameters of the form "?" without a following integer have no name 3315** and are referred to as "nameless" or "anonymous parameters". 3316** 3317** ^The first host parameter has an index of 1, not 0. 3318** 3319** ^If the value N is out of range or if the N-th parameter is 3320** nameless, then NULL is returned. ^The returned string is 3321** always in UTF-8 encoding even if the named parameter was 3322** originally specified as UTF-16 in [sqlite3_prepare16()] or 3323** [sqlite3_prepare16_v2()]. 3324** 3325** See also: [sqlite3_bind_blob|sqlite3_bind()], 3326** [sqlite3_bind_parameter_count()], and 3327** [sqlite3_bind_parameter_index()]. 3328*/ 3329const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3330 3331/* 3332** CAPI3REF: Index Of A Parameter With A Given Name 3333** 3334** ^Return the index of an SQL parameter given its name. ^The 3335** index value returned is suitable for use as the second 3336** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3337** is returned if no matching parameter is found. ^The parameter 3338** name must be given in UTF-8 even if the original statement 3339** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3340** 3341** See also: [sqlite3_bind_blob|sqlite3_bind()], 3342** [sqlite3_bind_parameter_count()], and 3343** [sqlite3_bind_parameter_index()]. 3344*/ 3345int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3346 3347/* 3348** CAPI3REF: Reset All Bindings On A Prepared Statement 3349** 3350** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3351** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3352** ^Use this routine to reset all host parameters to NULL. 3353*/ 3354int sqlite3_clear_bindings(sqlite3_stmt*); 3355 3356/* 3357** CAPI3REF: Number Of Columns In A Result Set 3358** 3359** ^Return the number of columns in the result set returned by the 3360** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3361** statement that does not return data (for example an [UPDATE]). 3362** 3363** See also: [sqlite3_data_count()] 3364*/ 3365int sqlite3_column_count(sqlite3_stmt *pStmt); 3366 3367/* 3368** CAPI3REF: Column Names In A Result Set 3369** 3370** ^These routines return the name assigned to a particular column 3371** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3372** interface returns a pointer to a zero-terminated UTF-8 string 3373** and sqlite3_column_name16() returns a pointer to a zero-terminated 3374** UTF-16 string. ^The first parameter is the [prepared statement] 3375** that implements the [SELECT] statement. ^The second parameter is the 3376** column number. ^The leftmost column is number 0. 3377** 3378** ^The returned string pointer is valid until either the [prepared statement] 3379** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3380** reprepared by the first call to [sqlite3_step()] for a particular run 3381** or until the next call to 3382** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3383** 3384** ^If sqlite3_malloc() fails during the processing of either routine 3385** (for example during a conversion from UTF-8 to UTF-16) then a 3386** NULL pointer is returned. 3387** 3388** ^The name of a result column is the value of the "AS" clause for 3389** that column, if there is an AS clause. If there is no AS clause 3390** then the name of the column is unspecified and may change from 3391** one release of SQLite to the next. 3392*/ 3393const char *sqlite3_column_name(sqlite3_stmt*, int N); 3394const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3395 3396/* 3397** CAPI3REF: Source Of Data In A Query Result 3398** 3399** ^These routines provide a means to determine the database, table, and 3400** table column that is the origin of a particular result column in 3401** [SELECT] statement. 3402** ^The name of the database or table or column can be returned as 3403** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3404** the database name, the _table_ routines return the table name, and 3405** the origin_ routines return the column name. 3406** ^The returned string is valid until the [prepared statement] is destroyed 3407** using [sqlite3_finalize()] or until the statement is automatically 3408** reprepared by the first call to [sqlite3_step()] for a particular run 3409** or until the same information is requested 3410** again in a different encoding. 3411** 3412** ^The names returned are the original un-aliased names of the 3413** database, table, and column. 3414** 3415** ^The first argument to these interfaces is a [prepared statement]. 3416** ^These functions return information about the Nth result column returned by 3417** the statement, where N is the second function argument. 3418** ^The left-most column is column 0 for these routines. 3419** 3420** ^If the Nth column returned by the statement is an expression or 3421** subquery and is not a column value, then all of these functions return 3422** NULL. ^These routine might also return NULL if a memory allocation error 3423** occurs. ^Otherwise, they return the name of the attached database, table, 3424** or column that query result column was extracted from. 3425** 3426** ^As with all other SQLite APIs, those whose names end with "16" return 3427** UTF-16 encoded strings and the other functions return UTF-8. 3428** 3429** ^These APIs are only available if the library was compiled with the 3430** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3431** 3432** If two or more threads call one or more of these routines against the same 3433** prepared statement and column at the same time then the results are 3434** undefined. 3435** 3436** If two or more threads call one or more 3437** [sqlite3_column_database_name | column metadata interfaces] 3438** for the same [prepared statement] and result column 3439** at the same time then the results are undefined. 3440*/ 3441const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3442const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3443const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3444const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3445const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3446const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3447 3448/* 3449** CAPI3REF: Declared Datatype Of A Query Result 3450** 3451** ^(The first parameter is a [prepared statement]. 3452** If this statement is a [SELECT] statement and the Nth column of the 3453** returned result set of that [SELECT] is a table column (not an 3454** expression or subquery) then the declared type of the table 3455** column is returned.)^ ^If the Nth column of the result set is an 3456** expression or subquery, then a NULL pointer is returned. 3457** ^The returned string is always UTF-8 encoded. 3458** 3459** ^(For example, given the database schema: 3460** 3461** CREATE TABLE t1(c1 VARIANT); 3462** 3463** and the following statement to be compiled: 3464** 3465** SELECT c1 + 1, c1 FROM t1; 3466** 3467** this routine would return the string "VARIANT" for the second result 3468** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3469** 3470** ^SQLite uses dynamic run-time typing. ^So just because a column 3471** is declared to contain a particular type does not mean that the 3472** data stored in that column is of the declared type. SQLite is 3473** strongly typed, but the typing is dynamic not static. ^Type 3474** is associated with individual values, not with the containers 3475** used to hold those values. 3476*/ 3477const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3478const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3479 3480/* 3481** CAPI3REF: Evaluate An SQL Statement 3482** 3483** After a [prepared statement] has been prepared using either 3484** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3485** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3486** must be called one or more times to evaluate the statement. 3487** 3488** The details of the behavior of the sqlite3_step() interface depend 3489** on whether the statement was prepared using the newer "v2" interface 3490** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3491** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3492** new "v2" interface is recommended for new applications but the legacy 3493** interface will continue to be supported. 3494** 3495** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3496** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3497** ^With the "v2" interface, any of the other [result codes] or 3498** [extended result codes] might be returned as well. 3499** 3500** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3501** database locks it needs to do its job. ^If the statement is a [COMMIT] 3502** or occurs outside of an explicit transaction, then you can retry the 3503** statement. If the statement is not a [COMMIT] and occurs within an 3504** explicit transaction then you should rollback the transaction before 3505** continuing. 3506** 3507** ^[SQLITE_DONE] means that the statement has finished executing 3508** successfully. sqlite3_step() should not be called again on this virtual 3509** machine without first calling [sqlite3_reset()] to reset the virtual 3510** machine back to its initial state. 3511** 3512** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3513** is returned each time a new row of data is ready for processing by the 3514** caller. The values may be accessed using the [column access functions]. 3515** sqlite3_step() is called again to retrieve the next row of data. 3516** 3517** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3518** violation) has occurred. sqlite3_step() should not be called again on 3519** the VM. More information may be found by calling [sqlite3_errmsg()]. 3520** ^With the legacy interface, a more specific error code (for example, 3521** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3522** can be obtained by calling [sqlite3_reset()] on the 3523** [prepared statement]. ^In the "v2" interface, 3524** the more specific error code is returned directly by sqlite3_step(). 3525** 3526** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3527** Perhaps it was called on a [prepared statement] that has 3528** already been [sqlite3_finalize | finalized] or on one that had 3529** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3530** be the case that the same database connection is being used by two or 3531** more threads at the same moment in time. 3532** 3533** For all versions of SQLite up to and including 3.6.23.1, a call to 3534** [sqlite3_reset()] was required after sqlite3_step() returned anything 3535** other than [SQLITE_ROW] before any subsequent invocation of 3536** sqlite3_step(). Failure to reset the prepared statement using 3537** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3538** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3539** calling [sqlite3_reset()] automatically in this circumstance rather 3540** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3541** break because any application that ever receives an SQLITE_MISUSE error 3542** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3543** can be used to restore the legacy behavior. 3544** 3545** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3546** API always returns a generic error code, [SQLITE_ERROR], following any 3547** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3548** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3549** specific [error codes] that better describes the error. 3550** We admit that this is a goofy design. The problem has been fixed 3551** with the "v2" interface. If you prepare all of your SQL statements 3552** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3553** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3554** then the more specific [error codes] are returned directly 3555** by sqlite3_step(). The use of the "v2" interface is recommended. 3556*/ 3557int sqlite3_step(sqlite3_stmt*); 3558 3559/* 3560** CAPI3REF: Number of columns in a result set 3561** 3562** ^The sqlite3_data_count(P) interface returns the number of columns in the 3563** current row of the result set of [prepared statement] P. 3564** ^If prepared statement P does not have results ready to return 3565** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3566** interfaces) then sqlite3_data_count(P) returns 0. 3567** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3568** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 3569** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 3570** will return non-zero if previous call to [sqlite3_step](P) returned 3571** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 3572** where it always returns zero since each step of that multi-step 3573** pragma returns 0 columns of data. 3574** 3575** See also: [sqlite3_column_count()] 3576*/ 3577int sqlite3_data_count(sqlite3_stmt *pStmt); 3578 3579/* 3580** CAPI3REF: Fundamental Datatypes 3581** KEYWORDS: SQLITE_TEXT 3582** 3583** ^(Every value in SQLite has one of five fundamental datatypes: 3584** 3585** <ul> 3586** <li> 64-bit signed integer 3587** <li> 64-bit IEEE floating point number 3588** <li> string 3589** <li> BLOB 3590** <li> NULL 3591** </ul>)^ 3592** 3593** These constants are codes for each of those types. 3594** 3595** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3596** for a completely different meaning. Software that links against both 3597** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3598** SQLITE_TEXT. 3599*/ 3600#define SQLITE_INTEGER 1 3601#define SQLITE_FLOAT 2 3602#define SQLITE_BLOB 4 3603#define SQLITE_NULL 5 3604#ifdef SQLITE_TEXT 3605# undef SQLITE_TEXT 3606#else 3607# define SQLITE_TEXT 3 3608#endif 3609#define SQLITE3_TEXT 3 3610 3611/* 3612** CAPI3REF: Result Values From A Query 3613** KEYWORDS: {column access functions} 3614** 3615** These routines form the "result set" interface. 3616** 3617** ^These routines return information about a single column of the current 3618** result row of a query. ^In every case the first argument is a pointer 3619** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3620** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3621** and the second argument is the index of the column for which information 3622** should be returned. ^The leftmost column of the result set has the index 0. 3623** ^The number of columns in the result can be determined using 3624** [sqlite3_column_count()]. 3625** 3626** If the SQL statement does not currently point to a valid row, or if the 3627** column index is out of range, the result is undefined. 3628** These routines may only be called when the most recent call to 3629** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3630** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3631** If any of these routines are called after [sqlite3_reset()] or 3632** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3633** something other than [SQLITE_ROW], the results are undefined. 3634** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3635** are called from a different thread while any of these routines 3636** are pending, then the results are undefined. 3637** 3638** ^The sqlite3_column_type() routine returns the 3639** [SQLITE_INTEGER | datatype code] for the initial data type 3640** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3641** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3642** returned by sqlite3_column_type() is only meaningful if no type 3643** conversions have occurred as described below. After a type conversion, 3644** the value returned by sqlite3_column_type() is undefined. Future 3645** versions of SQLite may change the behavior of sqlite3_column_type() 3646** following a type conversion. 3647** 3648** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3649** routine returns the number of bytes in that BLOB or string. 3650** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3651** the string to UTF-8 and then returns the number of bytes. 3652** ^If the result is a numeric value then sqlite3_column_bytes() uses 3653** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3654** the number of bytes in that string. 3655** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3656** 3657** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3658** routine returns the number of bytes in that BLOB or string. 3659** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3660** the string to UTF-16 and then returns the number of bytes. 3661** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3662** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3663** the number of bytes in that string. 3664** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3665** 3666** ^The values returned by [sqlite3_column_bytes()] and 3667** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3668** of the string. ^For clarity: the values returned by 3669** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3670** bytes in the string, not the number of characters. 3671** 3672** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3673** even empty strings, are always zero-terminated. ^The return 3674** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3675** 3676** ^The object returned by [sqlite3_column_value()] is an 3677** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3678** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3679** If the [unprotected sqlite3_value] object returned by 3680** [sqlite3_column_value()] is used in any other way, including calls 3681** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3682** or [sqlite3_value_bytes()], then the behavior is undefined. 3683** 3684** These routines attempt to convert the value where appropriate. ^For 3685** example, if the internal representation is FLOAT and a text result 3686** is requested, [sqlite3_snprintf()] is used internally to perform the 3687** conversion automatically. ^(The following table details the conversions 3688** that are applied: 3689** 3690** <blockquote> 3691** <table border="1"> 3692** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3693** 3694** <tr><td> NULL <td> INTEGER <td> Result is 0 3695** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3696** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3697** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3698** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3699** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3700** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3701** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3702** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3703** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3704** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3705** <tr><td> TEXT <td> FLOAT <td> Use atof() 3706** <tr><td> TEXT <td> BLOB <td> No change 3707** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3708** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3709** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3710** </table> 3711** </blockquote>)^ 3712** 3713** The table above makes reference to standard C library functions atoi() 3714** and atof(). SQLite does not really use these functions. It has its 3715** own equivalent internal routines. The atoi() and atof() names are 3716** used in the table for brevity and because they are familiar to most 3717** C programmers. 3718** 3719** Note that when type conversions occur, pointers returned by prior 3720** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3721** sqlite3_column_text16() may be invalidated. 3722** Type conversions and pointer invalidations might occur 3723** in the following cases: 3724** 3725** <ul> 3726** <li> The initial content is a BLOB and sqlite3_column_text() or 3727** sqlite3_column_text16() is called. A zero-terminator might 3728** need to be added to the string.</li> 3729** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3730** sqlite3_column_text16() is called. The content must be converted 3731** to UTF-16.</li> 3732** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3733** sqlite3_column_text() is called. The content must be converted 3734** to UTF-8.</li> 3735** </ul> 3736** 3737** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3738** not invalidate a prior pointer, though of course the content of the buffer 3739** that the prior pointer references will have been modified. Other kinds 3740** of conversion are done in place when it is possible, but sometimes they 3741** are not possible and in those cases prior pointers are invalidated. 3742** 3743** The safest and easiest to remember policy is to invoke these routines 3744** in one of the following ways: 3745** 3746** <ul> 3747** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3748** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3749** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3750** </ul> 3751** 3752** In other words, you should call sqlite3_column_text(), 3753** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3754** into the desired format, then invoke sqlite3_column_bytes() or 3755** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3756** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3757** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3758** with calls to sqlite3_column_bytes(). 3759** 3760** ^The pointers returned are valid until a type conversion occurs as 3761** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3762** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3763** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3764** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3765** [sqlite3_free()]. 3766** 3767** ^(If a memory allocation error occurs during the evaluation of any 3768** of these routines, a default value is returned. The default value 3769** is either the integer 0, the floating point number 0.0, or a NULL 3770** pointer. Subsequent calls to [sqlite3_errcode()] will return 3771** [SQLITE_NOMEM].)^ 3772*/ 3773const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3774int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3775int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3776double sqlite3_column_double(sqlite3_stmt*, int iCol); 3777int sqlite3_column_int(sqlite3_stmt*, int iCol); 3778sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3779const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3780const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3781int sqlite3_column_type(sqlite3_stmt*, int iCol); 3782sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3783 3784/* 3785** CAPI3REF: Destroy A Prepared Statement Object 3786** 3787** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3788** ^If the most recent evaluation of the statement encountered no errors 3789** or if the statement is never been evaluated, then sqlite3_finalize() returns 3790** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 3791** sqlite3_finalize(S) returns the appropriate [error code] or 3792** [extended error code]. 3793** 3794** ^The sqlite3_finalize(S) routine can be called at any point during 3795** the life cycle of [prepared statement] S: 3796** before statement S is ever evaluated, after 3797** one or more calls to [sqlite3_reset()], or after any call 3798** to [sqlite3_step()] regardless of whether or not the statement has 3799** completed execution. 3800** 3801** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 3802** 3803** The application must finalize every [prepared statement] in order to avoid 3804** resource leaks. It is a grievous error for the application to try to use 3805** a prepared statement after it has been finalized. Any use of a prepared 3806** statement after it has been finalized can result in undefined and 3807** undesirable behavior such as segfaults and heap corruption. 3808*/ 3809int sqlite3_finalize(sqlite3_stmt *pStmt); 3810 3811/* 3812** CAPI3REF: Reset A Prepared Statement Object 3813** 3814** The sqlite3_reset() function is called to reset a [prepared statement] 3815** object back to its initial state, ready to be re-executed. 3816** ^Any SQL statement variables that had values bound to them using 3817** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3818** Use [sqlite3_clear_bindings()] to reset the bindings. 3819** 3820** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3821** back to the beginning of its program. 3822** 3823** ^If the most recent call to [sqlite3_step(S)] for the 3824** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3825** or if [sqlite3_step(S)] has never before been called on S, 3826** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3827** 3828** ^If the most recent call to [sqlite3_step(S)] for the 3829** [prepared statement] S indicated an error, then 3830** [sqlite3_reset(S)] returns an appropriate [error code]. 3831** 3832** ^The [sqlite3_reset(S)] interface does not change the values 3833** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3834*/ 3835int sqlite3_reset(sqlite3_stmt *pStmt); 3836 3837/* 3838** CAPI3REF: Create Or Redefine SQL Functions 3839** KEYWORDS: {function creation routines} 3840** KEYWORDS: {application-defined SQL function} 3841** KEYWORDS: {application-defined SQL functions} 3842** 3843** ^These functions (collectively known as "function creation routines") 3844** are used to add SQL functions or aggregates or to redefine the behavior 3845** of existing SQL functions or aggregates. The only differences between 3846** these routines are the text encoding expected for 3847** the second parameter (the name of the function being created) 3848** and the presence or absence of a destructor callback for 3849** the application data pointer. 3850** 3851** ^The first parameter is the [database connection] to which the SQL 3852** function is to be added. ^If an application uses more than one database 3853** connection then application-defined SQL functions must be added 3854** to each database connection separately. 3855** 3856** ^The second parameter is the name of the SQL function to be created or 3857** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 3858** representation, exclusive of the zero-terminator. ^Note that the name 3859** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 3860** ^Any attempt to create a function with a longer name 3861** will result in [SQLITE_MISUSE] being returned. 3862** 3863** ^The third parameter (nArg) 3864** is the number of arguments that the SQL function or 3865** aggregate takes. ^If this parameter is -1, then the SQL function or 3866** aggregate may take any number of arguments between 0 and the limit 3867** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3868** parameter is less than -1 or greater than 127 then the behavior is 3869** undefined. 3870** 3871** ^The fourth parameter, eTextRep, specifies what 3872** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3873** its parameters. Every SQL function implementation must be able to work 3874** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3875** more efficient with one encoding than another. ^An application may 3876** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3877** times with the same function but with different values of eTextRep. 3878** ^When multiple implementations of the same function are available, SQLite 3879** will pick the one that involves the least amount of data conversion. 3880** If there is only a single implementation which does not care what text 3881** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3882** 3883** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3884** function can gain access to this pointer using [sqlite3_user_data()].)^ 3885** 3886** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 3887** pointers to C-language functions that implement the SQL function or 3888** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3889** callback only; NULL pointers must be passed as the xStep and xFinal 3890** parameters. ^An aggregate SQL function requires an implementation of xStep 3891** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 3892** SQL function or aggregate, pass NULL pointers for all three function 3893** callbacks. 3894** 3895** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 3896** then it is destructor for the application data pointer. 3897** The destructor is invoked when the function is deleted, either by being 3898** overloaded or when the database connection closes.)^ 3899** ^The destructor is also invoked if the call to 3900** sqlite3_create_function_v2() fails. 3901** ^When the destructor callback of the tenth parameter is invoked, it 3902** is passed a single argument which is a copy of the application data 3903** pointer which was the fifth parameter to sqlite3_create_function_v2(). 3904** 3905** ^It is permitted to register multiple implementations of the same 3906** functions with the same name but with either differing numbers of 3907** arguments or differing preferred text encodings. ^SQLite will use 3908** the implementation that most closely matches the way in which the 3909** SQL function is used. ^A function implementation with a non-negative 3910** nArg parameter is a better match than a function implementation with 3911** a negative nArg. ^A function where the preferred text encoding 3912** matches the database encoding is a better 3913** match than a function where the encoding is different. 3914** ^A function where the encoding difference is between UTF16le and UTF16be 3915** is a closer match than a function where the encoding difference is 3916** between UTF8 and UTF16. 3917** 3918** ^Built-in functions may be overloaded by new application-defined functions. 3919** 3920** ^An application-defined function is permitted to call other 3921** SQLite interfaces. However, such calls must not 3922** close the database connection nor finalize or reset the prepared 3923** statement in which the function is running. 3924*/ 3925int sqlite3_create_function( 3926 sqlite3 *db, 3927 const char *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_function16( 3936 sqlite3 *db, 3937 const void *zFunctionName, 3938 int nArg, 3939 int eTextRep, 3940 void *pApp, 3941 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3942 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3943 void (*xFinal)(sqlite3_context*) 3944); 3945int sqlite3_create_function_v2( 3946 sqlite3 *db, 3947 const char *zFunctionName, 3948 int nArg, 3949 int eTextRep, 3950 void *pApp, 3951 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3952 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3953 void (*xFinal)(sqlite3_context*), 3954 void(*xDestroy)(void*) 3955); 3956 3957/* 3958** CAPI3REF: Text Encodings 3959** 3960** These constant define integer codes that represent the various 3961** text encodings supported by SQLite. 3962*/ 3963#define SQLITE_UTF8 1 3964#define SQLITE_UTF16LE 2 3965#define SQLITE_UTF16BE 3 3966#define SQLITE_UTF16 4 /* Use native byte order */ 3967#define SQLITE_ANY 5 /* sqlite3_create_function only */ 3968#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3969 3970/* 3971** CAPI3REF: Deprecated Functions 3972** DEPRECATED 3973** 3974** These functions are [deprecated]. In order to maintain 3975** backwards compatibility with older code, these functions continue 3976** to be supported. However, new applications should avoid 3977** the use of these functions. To help encourage people to avoid 3978** using these functions, we are not going to tell you what they do. 3979*/ 3980#ifndef SQLITE_OMIT_DEPRECATED 3981SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3982SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3983SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3984SQLITE_DEPRECATED int sqlite3_global_recover(void); 3985SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3986SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3987#endif 3988 3989/* 3990** CAPI3REF: Obtaining SQL Function Parameter Values 3991** 3992** The C-language implementation of SQL functions and aggregates uses 3993** this set of interface routines to access the parameter values on 3994** the function or aggregate. 3995** 3996** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3997** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3998** define callbacks that implement the SQL functions and aggregates. 3999** The 3rd parameter to these callbacks is an array of pointers to 4000** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 4001** each parameter to the SQL function. These routines are used to 4002** extract values from the [sqlite3_value] objects. 4003** 4004** These routines work only with [protected sqlite3_value] objects. 4005** Any attempt to use these routines on an [unprotected sqlite3_value] 4006** object results in undefined behavior. 4007** 4008** ^These routines work just like the corresponding [column access functions] 4009** except that these routines take a single [protected sqlite3_value] object 4010** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4011** 4012** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4013** in the native byte-order of the host machine. ^The 4014** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4015** extract UTF-16 strings as big-endian and little-endian respectively. 4016** 4017** ^(The sqlite3_value_numeric_type() interface attempts to apply 4018** numeric affinity to the value. This means that an attempt is 4019** made to convert the value to an integer or floating point. If 4020** such a conversion is possible without loss of information (in other 4021** words, if the value is a string that looks like a number) 4022** then the conversion is performed. Otherwise no conversion occurs. 4023** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4024** 4025** Please pay particular attention to the fact that the pointer returned 4026** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4027** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4028** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4029** or [sqlite3_value_text16()]. 4030** 4031** These routines must be called from the same thread as 4032** the SQL function that supplied the [sqlite3_value*] parameters. 4033*/ 4034const void *sqlite3_value_blob(sqlite3_value*); 4035int sqlite3_value_bytes(sqlite3_value*); 4036int sqlite3_value_bytes16(sqlite3_value*); 4037double sqlite3_value_double(sqlite3_value*); 4038int sqlite3_value_int(sqlite3_value*); 4039sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4040const unsigned char *sqlite3_value_text(sqlite3_value*); 4041const void *sqlite3_value_text16(sqlite3_value*); 4042const void *sqlite3_value_text16le(sqlite3_value*); 4043const void *sqlite3_value_text16be(sqlite3_value*); 4044int sqlite3_value_type(sqlite3_value*); 4045int sqlite3_value_numeric_type(sqlite3_value*); 4046 4047/* 4048** CAPI3REF: Obtain Aggregate Function Context 4049** 4050** Implementations of aggregate SQL functions use this 4051** routine to allocate memory for storing their state. 4052** 4053** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4054** for a particular aggregate function, SQLite 4055** allocates N of memory, zeroes out that memory, and returns a pointer 4056** to the new memory. ^On second and subsequent calls to 4057** sqlite3_aggregate_context() for the same aggregate function instance, 4058** the same buffer is returned. Sqlite3_aggregate_context() is normally 4059** called once for each invocation of the xStep callback and then one 4060** last time when the xFinal callback is invoked. ^(When no rows match 4061** an aggregate query, the xStep() callback of the aggregate function 4062** implementation is never called and xFinal() is called exactly once. 4063** In those cases, sqlite3_aggregate_context() might be called for the 4064** first time from within xFinal().)^ 4065** 4066** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is 4067** less than or equal to zero or if a memory allocate error occurs. 4068** 4069** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4070** determined by the N parameter on first successful call. Changing the 4071** value of N in subsequent call to sqlite3_aggregate_context() within 4072** the same aggregate function instance will not resize the memory 4073** allocation.)^ 4074** 4075** ^SQLite automatically frees the memory allocated by 4076** sqlite3_aggregate_context() when the aggregate query concludes. 4077** 4078** The first parameter must be a copy of the 4079** [sqlite3_context | SQL function context] that is the first parameter 4080** to the xStep or xFinal callback routine that implements the aggregate 4081** function. 4082** 4083** This routine must be called from the same thread in which 4084** the aggregate SQL function is running. 4085*/ 4086void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4087 4088/* 4089** CAPI3REF: User Data For Functions 4090** 4091** ^The sqlite3_user_data() interface returns a copy of 4092** the pointer that was the pUserData parameter (the 5th parameter) 4093** of the [sqlite3_create_function()] 4094** and [sqlite3_create_function16()] routines that originally 4095** registered the application defined function. 4096** 4097** This routine must be called from the same thread in which 4098** the application-defined function is running. 4099*/ 4100void *sqlite3_user_data(sqlite3_context*); 4101 4102/* 4103** CAPI3REF: Database Connection For Functions 4104** 4105** ^The sqlite3_context_db_handle() interface returns a copy of 4106** the pointer to the [database connection] (the 1st parameter) 4107** of the [sqlite3_create_function()] 4108** and [sqlite3_create_function16()] routines that originally 4109** registered the application defined function. 4110*/ 4111sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4112 4113/* 4114** CAPI3REF: Function Auxiliary Data 4115** 4116** The following two functions may be used by scalar SQL functions to 4117** associate metadata with argument values. If the same value is passed to 4118** multiple invocations of the same SQL function during query execution, under 4119** some circumstances the associated metadata may be preserved. This may 4120** be used, for example, to add a regular-expression matching scalar 4121** function. The compiled version of the regular expression is stored as 4122** metadata associated with the SQL value passed as the regular expression 4123** pattern. The compiled regular expression can be reused on multiple 4124** invocations of the same function so that the original pattern string 4125** does not need to be recompiled on each invocation. 4126** 4127** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4128** associated by the sqlite3_set_auxdata() function with the Nth argument 4129** value to the application-defined function. ^If no metadata has been ever 4130** been set for the Nth argument of the function, or if the corresponding 4131** function parameter has changed since the meta-data was set, 4132** then sqlite3_get_auxdata() returns a NULL pointer. 4133** 4134** ^The sqlite3_set_auxdata() interface saves the metadata 4135** pointed to by its 3rd parameter as the metadata for the N-th 4136** argument of the application-defined function. Subsequent 4137** calls to sqlite3_get_auxdata() might return this data, if it has 4138** not been destroyed. 4139** ^If it is not NULL, SQLite will invoke the destructor 4140** function given by the 4th parameter to sqlite3_set_auxdata() on 4141** the metadata when the corresponding function parameter changes 4142** or when the SQL statement completes, whichever comes first. 4143** 4144** SQLite is free to call the destructor and drop metadata on any 4145** parameter of any function at any time. ^The only guarantee is that 4146** the destructor will be called before the metadata is dropped. 4147** 4148** ^(In practice, metadata is preserved between function calls for 4149** expressions that are constant at compile time. This includes literal 4150** values and [parameters].)^ 4151** 4152** These routines must be called from the same thread in which 4153** the SQL function is running. 4154*/ 4155void *sqlite3_get_auxdata(sqlite3_context*, int N); 4156void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4157 4158 4159/* 4160** CAPI3REF: Constants Defining Special Destructor Behavior 4161** 4162** These are special values for the destructor that is passed in as the 4163** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4164** argument is SQLITE_STATIC, it means that the content pointer is constant 4165** and will never change. It does not need to be destroyed. ^The 4166** SQLITE_TRANSIENT value means that the content will likely change in 4167** the near future and that SQLite should make its own private copy of 4168** the content before returning. 4169** 4170** The typedef is necessary to work around problems in certain 4171** C++ compilers. See ticket #2191. 4172*/ 4173typedef void (*sqlite3_destructor_type)(void*); 4174#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4175#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4176 4177/* 4178** CAPI3REF: Setting The Result Of An SQL Function 4179** 4180** These routines are used by the xFunc or xFinal callbacks that 4181** implement SQL functions and aggregates. See 4182** [sqlite3_create_function()] and [sqlite3_create_function16()] 4183** for additional information. 4184** 4185** These functions work very much like the [parameter binding] family of 4186** functions used to bind values to host parameters in prepared statements. 4187** Refer to the [SQL parameter] documentation for additional information. 4188** 4189** ^The sqlite3_result_blob() interface sets the result from 4190** an application-defined function to be the BLOB whose content is pointed 4191** to by the second parameter and which is N bytes long where N is the 4192** third parameter. 4193** 4194** ^The sqlite3_result_zeroblob() interfaces set the result of 4195** the application-defined function to be a BLOB containing all zero 4196** bytes and N bytes in size, where N is the value of the 2nd parameter. 4197** 4198** ^The sqlite3_result_double() interface sets the result from 4199** an application-defined function to be a floating point value specified 4200** by its 2nd argument. 4201** 4202** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4203** cause the implemented SQL function to throw an exception. 4204** ^SQLite uses the string pointed to by the 4205** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4206** as the text of an error message. ^SQLite interprets the error 4207** message string from sqlite3_result_error() as UTF-8. ^SQLite 4208** interprets the string from sqlite3_result_error16() as UTF-16 in native 4209** byte order. ^If the third parameter to sqlite3_result_error() 4210** or sqlite3_result_error16() is negative then SQLite takes as the error 4211** message all text up through the first zero character. 4212** ^If the third parameter to sqlite3_result_error() or 4213** sqlite3_result_error16() is non-negative then SQLite takes that many 4214** bytes (not characters) from the 2nd parameter as the error message. 4215** ^The sqlite3_result_error() and sqlite3_result_error16() 4216** routines make a private copy of the error message text before 4217** they return. Hence, the calling function can deallocate or 4218** modify the text after they return without harm. 4219** ^The sqlite3_result_error_code() function changes the error code 4220** returned by SQLite as a result of an error in a function. ^By default, 4221** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4222** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4223** 4224** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 4225** error indicating that a string or BLOB is too long to represent. 4226** 4227** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 4228** error indicating that a memory allocation failed. 4229** 4230** ^The sqlite3_result_int() interface sets the return value 4231** of the application-defined function to be the 32-bit signed integer 4232** value given in the 2nd argument. 4233** ^The sqlite3_result_int64() interface sets the return value 4234** of the application-defined function to be the 64-bit signed integer 4235** value given in the 2nd argument. 4236** 4237** ^The sqlite3_result_null() interface sets the return value 4238** of the application-defined function to be NULL. 4239** 4240** ^The sqlite3_result_text(), sqlite3_result_text16(), 4241** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4242** set the return value of the application-defined function to be 4243** a text string which is represented as UTF-8, UTF-16 native byte order, 4244** UTF-16 little endian, or UTF-16 big endian, respectively. 4245** ^SQLite takes the text result from the application from 4246** the 2nd parameter of the sqlite3_result_text* interfaces. 4247** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4248** is negative, then SQLite takes result text from the 2nd parameter 4249** through the first zero character. 4250** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4251** is non-negative, then as many bytes (not characters) of the text 4252** pointed to by the 2nd parameter are taken as the application-defined 4253** function result. If the 3rd parameter is non-negative, then it 4254** must be the byte offset into the string where the NUL terminator would 4255** appear if the string where NUL terminated. If any NUL characters occur 4256** in the string at a byte offset that is less than the value of the 3rd 4257** parameter, then the resulting string will contain embedded NULs and the 4258** result of expressions operating on strings with embedded NULs is undefined. 4259** ^If the 4th parameter to the sqlite3_result_text* interfaces 4260** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4261** function as the destructor on the text or BLOB result when it has 4262** finished using that result. 4263** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4264** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4265** assumes that the text or BLOB result is in constant space and does not 4266** copy the content of the parameter nor call a destructor on the content 4267** when it has finished using that result. 4268** ^If the 4th parameter to the sqlite3_result_text* interfaces 4269** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4270** then SQLite makes a copy of the result into space obtained from 4271** from [sqlite3_malloc()] before it returns. 4272** 4273** ^The sqlite3_result_value() interface sets the result of 4274** the application-defined function to be a copy the 4275** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4276** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4277** so that the [sqlite3_value] specified in the parameter may change or 4278** be deallocated after sqlite3_result_value() returns without harm. 4279** ^A [protected sqlite3_value] object may always be used where an 4280** [unprotected sqlite3_value] object is required, so either 4281** kind of [sqlite3_value] object can be used with this interface. 4282** 4283** If these routines are called from within the different thread 4284** than the one containing the application-defined function that received 4285** the [sqlite3_context] pointer, the results are undefined. 4286*/ 4287void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4288void sqlite3_result_double(sqlite3_context*, double); 4289void sqlite3_result_error(sqlite3_context*, const char*, int); 4290void sqlite3_result_error16(sqlite3_context*, const void*, int); 4291void sqlite3_result_error_toobig(sqlite3_context*); 4292void sqlite3_result_error_nomem(sqlite3_context*); 4293void sqlite3_result_error_code(sqlite3_context*, int); 4294void sqlite3_result_int(sqlite3_context*, int); 4295void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4296void sqlite3_result_null(sqlite3_context*); 4297void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4298void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4299void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4300void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4301void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4302void sqlite3_result_zeroblob(sqlite3_context*, int n); 4303 4304/* 4305** CAPI3REF: Define New Collating Sequences 4306** 4307** ^These functions add, remove, or modify a [collation] associated 4308** with the [database connection] specified as the first argument. 4309** 4310** ^The name of the collation is a UTF-8 string 4311** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4312** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4313** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4314** considered to be the same name. 4315** 4316** ^(The third argument (eTextRep) must be one of the constants: 4317** <ul> 4318** <li> [SQLITE_UTF8], 4319** <li> [SQLITE_UTF16LE], 4320** <li> [SQLITE_UTF16BE], 4321** <li> [SQLITE_UTF16], or 4322** <li> [SQLITE_UTF16_ALIGNED]. 4323** </ul>)^ 4324** ^The eTextRep argument determines the encoding of strings passed 4325** to the collating function callback, xCallback. 4326** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4327** force strings to be UTF16 with native byte order. 4328** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4329** on an even byte address. 4330** 4331** ^The fourth argument, pArg, is an application data pointer that is passed 4332** through as the first argument to the collating function callback. 4333** 4334** ^The fifth argument, xCallback, is a pointer to the collating function. 4335** ^Multiple collating functions can be registered using the same name but 4336** with different eTextRep parameters and SQLite will use whichever 4337** function requires the least amount of data transformation. 4338** ^If the xCallback argument is NULL then the collating function is 4339** deleted. ^When all collating functions having the same name are deleted, 4340** that collation is no longer usable. 4341** 4342** ^The collating function callback is invoked with a copy of the pArg 4343** application data pointer and with two strings in the encoding specified 4344** by the eTextRep argument. The collating function must return an 4345** integer that is negative, zero, or positive 4346** if the first string is less than, equal to, or greater than the second, 4347** respectively. A collating function must always return the same answer 4348** given the same inputs. If two or more collating functions are registered 4349** to the same collation name (using different eTextRep values) then all 4350** must give an equivalent answer when invoked with equivalent strings. 4351** The collating function must obey the following properties for all 4352** strings A, B, and C: 4353** 4354** <ol> 4355** <li> If A==B then B==A. 4356** <li> If A==B and B==C then A==C. 4357** <li> If A<B THEN B>A. 4358** <li> If A<B and B<C then A<C. 4359** </ol> 4360** 4361** If a collating function fails any of the above constraints and that 4362** collating function is registered and used, then the behavior of SQLite 4363** is undefined. 4364** 4365** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4366** with the addition that the xDestroy callback is invoked on pArg when 4367** the collating function is deleted. 4368** ^Collating functions are deleted when they are overridden by later 4369** calls to the collation creation functions or when the 4370** [database connection] is closed using [sqlite3_close()]. 4371** 4372** ^The xDestroy callback is <u>not</u> called if the 4373** sqlite3_create_collation_v2() function fails. Applications that invoke 4374** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4375** check the return code and dispose of the application data pointer 4376** themselves rather than expecting SQLite to deal with it for them. 4377** This is different from every other SQLite interface. The inconsistency 4378** is unfortunate but cannot be changed without breaking backwards 4379** compatibility. 4380** 4381** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4382*/ 4383int sqlite3_create_collation( 4384 sqlite3*, 4385 const char *zName, 4386 int eTextRep, 4387 void *pArg, 4388 int(*xCompare)(void*,int,const void*,int,const void*) 4389); 4390int sqlite3_create_collation_v2( 4391 sqlite3*, 4392 const char *zName, 4393 int eTextRep, 4394 void *pArg, 4395 int(*xCompare)(void*,int,const void*,int,const void*), 4396 void(*xDestroy)(void*) 4397); 4398int sqlite3_create_collation16( 4399 sqlite3*, 4400 const void *zName, 4401 int eTextRep, 4402 void *pArg, 4403 int(*xCompare)(void*,int,const void*,int,const void*) 4404); 4405 4406/* 4407** CAPI3REF: Collation Needed Callbacks 4408** 4409** ^To avoid having to register all collation sequences before a database 4410** can be used, a single callback function may be registered with the 4411** [database connection] to be invoked whenever an undefined collation 4412** sequence is required. 4413** 4414** ^If the function is registered using the sqlite3_collation_needed() API, 4415** then it is passed the names of undefined collation sequences as strings 4416** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4417** the names are passed as UTF-16 in machine native byte order. 4418** ^A call to either function replaces the existing collation-needed callback. 4419** 4420** ^(When the callback is invoked, the first argument passed is a copy 4421** of the second argument to sqlite3_collation_needed() or 4422** sqlite3_collation_needed16(). The second argument is the database 4423** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4424** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4425** sequence function required. The fourth parameter is the name of the 4426** required collation sequence.)^ 4427** 4428** The callback function should register the desired collation using 4429** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4430** [sqlite3_create_collation_v2()]. 4431*/ 4432int sqlite3_collation_needed( 4433 sqlite3*, 4434 void*, 4435 void(*)(void*,sqlite3*,int eTextRep,const char*) 4436); 4437int sqlite3_collation_needed16( 4438 sqlite3*, 4439 void*, 4440 void(*)(void*,sqlite3*,int eTextRep,const void*) 4441); 4442 4443#ifdef SQLITE_HAS_CODEC 4444/* 4445** Specify the key for an encrypted database. This routine should be 4446** called right after sqlite3_open(). 4447** 4448** The code to implement this API is not available in the public release 4449** of SQLite. 4450*/ 4451int sqlite3_key( 4452 sqlite3 *db, /* Database to be rekeyed */ 4453 const void *pKey, int nKey /* The key */ 4454); 4455 4456/* 4457** Change the key on an open database. If the current database is not 4458** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4459** database is decrypted. 4460** 4461** The code to implement this API is not available in the public release 4462** of SQLite. 4463*/ 4464int sqlite3_rekey( 4465 sqlite3 *db, /* Database to be rekeyed */ 4466 const void *pKey, int nKey /* The new key */ 4467); 4468 4469/* 4470** Specify the activation key for a SEE database. Unless 4471** activated, none of the SEE routines will work. 4472*/ 4473void sqlite3_activate_see( 4474 const char *zPassPhrase /* Activation phrase */ 4475); 4476#endif 4477 4478#ifdef SQLITE_ENABLE_CEROD 4479/* 4480** Specify the activation key for a CEROD database. Unless 4481** activated, none of the CEROD routines will work. 4482*/ 4483void sqlite3_activate_cerod( 4484 const char *zPassPhrase /* Activation phrase */ 4485); 4486#endif 4487 4488/* 4489** CAPI3REF: Suspend Execution For A Short Time 4490** 4491** The sqlite3_sleep() function causes the current thread to suspend execution 4492** for at least a number of milliseconds specified in its parameter. 4493** 4494** If the operating system does not support sleep requests with 4495** millisecond time resolution, then the time will be rounded up to 4496** the nearest second. The number of milliseconds of sleep actually 4497** requested from the operating system is returned. 4498** 4499** ^SQLite implements this interface by calling the xSleep() 4500** method of the default [sqlite3_vfs] object. If the xSleep() method 4501** of the default VFS is not implemented correctly, or not implemented at 4502** all, then the behavior of sqlite3_sleep() may deviate from the description 4503** in the previous paragraphs. 4504*/ 4505int sqlite3_sleep(int); 4506 4507/* 4508** CAPI3REF: Name Of The Folder Holding Temporary Files 4509** 4510** ^(If this global variable is made to point to a string which is 4511** the name of a folder (a.k.a. directory), then all temporary files 4512** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4513** will be placed in that directory.)^ ^If this variable 4514** is a NULL pointer, then SQLite performs a search for an appropriate 4515** temporary file directory. 4516** 4517** It is not safe to read or modify this variable in more than one 4518** thread at a time. It is not safe to read or modify this variable 4519** if a [database connection] is being used at the same time in a separate 4520** thread. 4521** It is intended that this variable be set once 4522** as part of process initialization and before any SQLite interface 4523** routines have been called and that this variable remain unchanged 4524** thereafter. 4525** 4526** ^The [temp_store_directory pragma] may modify this variable and cause 4527** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4528** the [temp_store_directory pragma] always assumes that any string 4529** that this variable points to is held in memory obtained from 4530** [sqlite3_malloc] and the pragma may attempt to free that memory 4531** using [sqlite3_free]. 4532** Hence, if this variable is modified directly, either it should be 4533** made NULL or made to point to memory obtained from [sqlite3_malloc] 4534** or else the use of the [temp_store_directory pragma] should be avoided. 4535** 4536** <b>Note to Windows Runtime users:</b> The temporary directory must be set 4537** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 4538** features that require the use of temporary files may fail. Here is an 4539** example of how to do this using C++ with the Windows Runtime: 4540** 4541** <blockquote><pre> 4542** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 4543** TemporaryFolder->Path->Data(); 4544** char zPathBuf[MAX_PATH + 1]; 4545** memset(zPathBuf, 0, sizeof(zPathBuf)); 4546** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 4547** NULL, NULL); 4548** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 4549** </pre></blockquote> 4550*/ 4551SQLITE_EXTERN char *sqlite3_temp_directory; 4552 4553/* 4554** CAPI3REF: Name Of The Folder Holding Database Files 4555** 4556** ^(If this global variable is made to point to a string which is 4557** the name of a folder (a.k.a. directory), then all database files 4558** specified with a relative pathname and created or accessed by 4559** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 4560** to be relative to that directory.)^ ^If this variable is a NULL 4561** pointer, then SQLite assumes that all database files specified 4562** with a relative pathname are relative to the current directory 4563** for the process. Only the windows VFS makes use of this global 4564** variable; it is ignored by the unix VFS. 4565** 4566** Changing the value of this variable while a database connection is 4567** open can result in a corrupt database. 4568** 4569** It is not safe to read or modify this variable in more than one 4570** thread at a time. It is not safe to read or modify this variable 4571** if a [database connection] is being used at the same time in a separate 4572** thread. 4573** It is intended that this variable be set once 4574** as part of process initialization and before any SQLite interface 4575** routines have been called and that this variable remain unchanged 4576** thereafter. 4577** 4578** ^The [data_store_directory pragma] may modify this variable and cause 4579** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4580** the [data_store_directory pragma] always assumes that any string 4581** that this variable points to is held in memory obtained from 4582** [sqlite3_malloc] and the pragma may attempt to free that memory 4583** using [sqlite3_free]. 4584** Hence, if this variable is modified directly, either it should be 4585** made NULL or made to point to memory obtained from [sqlite3_malloc] 4586** or else the use of the [data_store_directory pragma] should be avoided. 4587*/ 4588SQLITE_EXTERN char *sqlite3_data_directory; 4589 4590/* 4591** CAPI3REF: Test For Auto-Commit Mode 4592** KEYWORDS: {autocommit mode} 4593** 4594** ^The sqlite3_get_autocommit() interface returns non-zero or 4595** zero if the given database connection is or is not in autocommit mode, 4596** respectively. ^Autocommit mode is on by default. 4597** ^Autocommit mode is disabled by a [BEGIN] statement. 4598** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 4599** 4600** If certain kinds of errors occur on a statement within a multi-statement 4601** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 4602** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 4603** transaction might be rolled back automatically. The only way to 4604** find out whether SQLite automatically rolled back the transaction after 4605** an error is to use this function. 4606** 4607** If another thread changes the autocommit status of the database 4608** connection while this routine is running, then the return value 4609** is undefined. 4610*/ 4611int sqlite3_get_autocommit(sqlite3*); 4612 4613/* 4614** CAPI3REF: Find The Database Handle Of A Prepared Statement 4615** 4616** ^The sqlite3_db_handle interface returns the [database connection] handle 4617** to which a [prepared statement] belongs. ^The [database connection] 4618** returned by sqlite3_db_handle is the same [database connection] 4619** that was the first argument 4620** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 4621** create the statement in the first place. 4622*/ 4623sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 4624 4625/* 4626** CAPI3REF: Return The Filename For A Database Connection 4627** 4628** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 4629** associated with database N of connection D. ^The main database file 4630** has the name "main". If there is no attached database N on the database 4631** connection D, or if database N is a temporary or in-memory database, then 4632** a NULL pointer is returned. 4633** 4634** ^The filename returned by this function is the output of the 4635** xFullPathname method of the [VFS]. ^In other words, the filename 4636** will be an absolute pathname, even if the filename used 4637** to open the database originally was a URI or relative pathname. 4638*/ 4639const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 4640 4641/* 4642** CAPI3REF: Determine if a database is read-only 4643** 4644** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 4645** of connection D is read-only, 0 if it is read/write, or -1 if N is not 4646** the name of a database on connection D. 4647*/ 4648int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 4649 4650/* 4651** CAPI3REF: Find the next prepared statement 4652** 4653** ^This interface returns a pointer to the next [prepared statement] after 4654** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 4655** then this interface returns a pointer to the first prepared statement 4656** associated with the database connection pDb. ^If no prepared statement 4657** satisfies the conditions of this routine, it returns NULL. 4658** 4659** The [database connection] pointer D in a call to 4660** [sqlite3_next_stmt(D,S)] must refer to an open database 4661** connection and in particular must not be a NULL pointer. 4662*/ 4663sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 4664 4665/* 4666** CAPI3REF: Commit And Rollback Notification Callbacks 4667** 4668** ^The sqlite3_commit_hook() interface registers a callback 4669** function to be invoked whenever a transaction is [COMMIT | committed]. 4670** ^Any callback set by a previous call to sqlite3_commit_hook() 4671** for the same database connection is overridden. 4672** ^The sqlite3_rollback_hook() interface registers a callback 4673** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 4674** ^Any callback set by a previous call to sqlite3_rollback_hook() 4675** for the same database connection is overridden. 4676** ^The pArg argument is passed through to the callback. 4677** ^If the callback on a commit hook function returns non-zero, 4678** then the commit is converted into a rollback. 4679** 4680** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 4681** return the P argument from the previous call of the same function 4682** on the same [database connection] D, or NULL for 4683** the first call for each function on D. 4684** 4685** The commit and rollback hook callbacks are not reentrant. 4686** The callback implementation must not do anything that will modify 4687** the database connection that invoked the callback. Any actions 4688** to modify the database connection must be deferred until after the 4689** completion of the [sqlite3_step()] call that triggered the commit 4690** or rollback hook in the first place. 4691** Note that running any other SQL statements, including SELECT statements, 4692** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 4693** the database connections for the meaning of "modify" in this paragraph. 4694** 4695** ^Registering a NULL function disables the callback. 4696** 4697** ^When the commit hook callback routine returns zero, the [COMMIT] 4698** operation is allowed to continue normally. ^If the commit hook 4699** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 4700** ^The rollback hook is invoked on a rollback that results from a commit 4701** hook returning non-zero, just as it would be with any other rollback. 4702** 4703** ^For the purposes of this API, a transaction is said to have been 4704** rolled back if an explicit "ROLLBACK" statement is executed, or 4705** an error or constraint causes an implicit rollback to occur. 4706** ^The rollback callback is not invoked if a transaction is 4707** automatically rolled back because the database connection is closed. 4708** 4709** See also the [sqlite3_update_hook()] interface. 4710*/ 4711void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 4712void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 4713 4714/* 4715** CAPI3REF: Data Change Notification Callbacks 4716** 4717** ^The sqlite3_update_hook() interface registers a callback function 4718** with the [database connection] identified by the first argument 4719** to be invoked whenever a row is updated, inserted or deleted. 4720** ^Any callback set by a previous call to this function 4721** for the same database connection is overridden. 4722** 4723** ^The second argument is a pointer to the function to invoke when a 4724** row is updated, inserted or deleted. 4725** ^The first argument to the callback is a copy of the third argument 4726** to sqlite3_update_hook(). 4727** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 4728** or [SQLITE_UPDATE], depending on the operation that caused the callback 4729** to be invoked. 4730** ^The third and fourth arguments to the callback contain pointers to the 4731** database and table name containing the affected row. 4732** ^The final callback parameter is the [rowid] of the row. 4733** ^In the case of an update, this is the [rowid] after the update takes place. 4734** 4735** ^(The update hook is not invoked when internal system tables are 4736** modified (i.e. sqlite_master and sqlite_sequence).)^ 4737** 4738** ^In the current implementation, the update hook 4739** is not invoked when duplication rows are deleted because of an 4740** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 4741** invoked when rows are deleted using the [truncate optimization]. 4742** The exceptions defined in this paragraph might change in a future 4743** release of SQLite. 4744** 4745** The update hook implementation must not do anything that will modify 4746** the database connection that invoked the update hook. Any actions 4747** to modify the database connection must be deferred until after the 4748** completion of the [sqlite3_step()] call that triggered the update hook. 4749** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4750** database connections for the meaning of "modify" in this paragraph. 4751** 4752** ^The sqlite3_update_hook(D,C,P) function 4753** returns the P argument from the previous call 4754** on the same [database connection] D, or NULL for 4755** the first call on D. 4756** 4757** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4758** interfaces. 4759*/ 4760void *sqlite3_update_hook( 4761 sqlite3*, 4762 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4763 void* 4764); 4765 4766/* 4767** CAPI3REF: Enable Or Disable Shared Pager Cache 4768** 4769** ^(This routine enables or disables the sharing of the database cache 4770** and schema data structures between [database connection | connections] 4771** to the same database. Sharing is enabled if the argument is true 4772** and disabled if the argument is false.)^ 4773** 4774** ^Cache sharing is enabled and disabled for an entire process. 4775** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4776** sharing was enabled or disabled for each thread separately. 4777** 4778** ^(The cache sharing mode set by this interface effects all subsequent 4779** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4780** Existing database connections continue use the sharing mode 4781** that was in effect at the time they were opened.)^ 4782** 4783** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4784** successfully. An [error code] is returned otherwise.)^ 4785** 4786** ^Shared cache is disabled by default. But this might change in 4787** future releases of SQLite. Applications that care about shared 4788** cache setting should set it explicitly. 4789** 4790** This interface is threadsafe on processors where writing a 4791** 32-bit integer is atomic. 4792** 4793** See Also: [SQLite Shared-Cache Mode] 4794*/ 4795int sqlite3_enable_shared_cache(int); 4796 4797/* 4798** CAPI3REF: Attempt To Free Heap Memory 4799** 4800** ^The sqlite3_release_memory() interface attempts to free N bytes 4801** of heap memory by deallocating non-essential memory allocations 4802** held by the database library. Memory used to cache database 4803** pages to improve performance is an example of non-essential memory. 4804** ^sqlite3_release_memory() returns the number of bytes actually freed, 4805** which might be more or less than the amount requested. 4806** ^The sqlite3_release_memory() routine is a no-op returning zero 4807** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4808** 4809** See also: [sqlite3_db_release_memory()] 4810*/ 4811int sqlite3_release_memory(int); 4812 4813/* 4814** CAPI3REF: Free Memory Used By A Database Connection 4815** 4816** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 4817** memory as possible from database connection D. Unlike the 4818** [sqlite3_release_memory()] interface, this interface is effect even 4819** when then [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 4820** omitted. 4821** 4822** See also: [sqlite3_release_memory()] 4823*/ 4824int sqlite3_db_release_memory(sqlite3*); 4825 4826/* 4827** CAPI3REF: Impose A Limit On Heap Size 4828** 4829** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 4830** soft limit on the amount of heap memory that may be allocated by SQLite. 4831** ^SQLite strives to keep heap memory utilization below the soft heap 4832** limit by reducing the number of pages held in the page cache 4833** as heap memory usages approaches the limit. 4834** ^The soft heap limit is "soft" because even though SQLite strives to stay 4835** below the limit, it will exceed the limit rather than generate 4836** an [SQLITE_NOMEM] error. In other words, the soft heap limit 4837** is advisory only. 4838** 4839** ^The return value from sqlite3_soft_heap_limit64() is the size of 4840** the soft heap limit prior to the call, or negative in the case of an 4841** error. ^If the argument N is negative 4842** then no change is made to the soft heap limit. Hence, the current 4843** size of the soft heap limit can be determined by invoking 4844** sqlite3_soft_heap_limit64() with a negative argument. 4845** 4846** ^If the argument N is zero then the soft heap limit is disabled. 4847** 4848** ^(The soft heap limit is not enforced in the current implementation 4849** if one or more of following conditions are true: 4850** 4851** <ul> 4852** <li> The soft heap limit is set to zero. 4853** <li> Memory accounting is disabled using a combination of the 4854** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 4855** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 4856** <li> An alternative page cache implementation is specified using 4857** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 4858** <li> The page cache allocates from its own memory pool supplied 4859** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 4860** from the heap. 4861** </ul>)^ 4862** 4863** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 4864** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 4865** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 4866** the soft heap limit is enforced on every memory allocation. Without 4867** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 4868** when memory is allocated by the page cache. Testing suggests that because 4869** the page cache is the predominate memory user in SQLite, most 4870** applications will achieve adequate soft heap limit enforcement without 4871** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4872** 4873** The circumstances under which SQLite will enforce the soft heap limit may 4874** changes in future releases of SQLite. 4875*/ 4876sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 4877 4878/* 4879** CAPI3REF: Deprecated Soft Heap Limit Interface 4880** DEPRECATED 4881** 4882** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 4883** interface. This routine is provided for historical compatibility 4884** only. All new applications should use the 4885** [sqlite3_soft_heap_limit64()] interface rather than this one. 4886*/ 4887SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 4888 4889 4890/* 4891** CAPI3REF: Extract Metadata About A Column Of A Table 4892** 4893** ^This routine returns metadata about a specific column of a specific 4894** database table accessible using the [database connection] handle 4895** passed as the first function argument. 4896** 4897** ^The column is identified by the second, third and fourth parameters to 4898** this function. ^The second parameter is either the name of the database 4899** (i.e. "main", "temp", or an attached database) containing the specified 4900** table or NULL. ^If it is NULL, then all attached databases are searched 4901** for the table using the same algorithm used by the database engine to 4902** resolve unqualified table references. 4903** 4904** ^The third and fourth parameters to this function are the table and column 4905** name of the desired column, respectively. Neither of these parameters 4906** may be NULL. 4907** 4908** ^Metadata is returned by writing to the memory locations passed as the 5th 4909** and subsequent parameters to this function. ^Any of these arguments may be 4910** NULL, in which case the corresponding element of metadata is omitted. 4911** 4912** ^(<blockquote> 4913** <table border="1"> 4914** <tr><th> Parameter <th> Output<br>Type <th> Description 4915** 4916** <tr><td> 5th <td> const char* <td> Data type 4917** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4918** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4919** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4920** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4921** </table> 4922** </blockquote>)^ 4923** 4924** ^The memory pointed to by the character pointers returned for the 4925** declaration type and collation sequence is valid only until the next 4926** call to any SQLite API function. 4927** 4928** ^If the specified table is actually a view, an [error code] is returned. 4929** 4930** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4931** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4932** parameters are set for the explicitly declared column. ^(If there is no 4933** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4934** parameters are set as follows: 4935** 4936** <pre> 4937** data type: "INTEGER" 4938** collation sequence: "BINARY" 4939** not null: 0 4940** primary key: 1 4941** auto increment: 0 4942** </pre>)^ 4943** 4944** ^(This function may load one or more schemas from database files. If an 4945** error occurs during this process, or if the requested table or column 4946** cannot be found, an [error code] is returned and an error message left 4947** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4948** 4949** ^This API is only available if the library was compiled with the 4950** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4951*/ 4952int sqlite3_table_column_metadata( 4953 sqlite3 *db, /* Connection handle */ 4954 const char *zDbName, /* Database name or NULL */ 4955 const char *zTableName, /* Table name */ 4956 const char *zColumnName, /* Column name */ 4957 char const **pzDataType, /* OUTPUT: Declared data type */ 4958 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4959 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4960 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4961 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4962); 4963 4964/* 4965** CAPI3REF: Load An Extension 4966** 4967** ^This interface loads an SQLite extension library from the named file. 4968** 4969** ^The sqlite3_load_extension() interface attempts to load an 4970** SQLite extension library contained in the file zFile. 4971** 4972** ^The entry point is zProc. 4973** ^zProc may be 0, in which case the name of the entry point 4974** defaults to "sqlite3_extension_init". 4975** ^The sqlite3_load_extension() interface returns 4976** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4977** ^If an error occurs and pzErrMsg is not 0, then the 4978** [sqlite3_load_extension()] interface shall attempt to 4979** fill *pzErrMsg with error message text stored in memory 4980** obtained from [sqlite3_malloc()]. The calling function 4981** should free this memory by calling [sqlite3_free()]. 4982** 4983** ^Extension loading must be enabled using 4984** [sqlite3_enable_load_extension()] prior to calling this API, 4985** otherwise an error will be returned. 4986** 4987** See also the [load_extension() SQL function]. 4988*/ 4989int sqlite3_load_extension( 4990 sqlite3 *db, /* Load the extension into this database connection */ 4991 const char *zFile, /* Name of the shared library containing extension */ 4992 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4993 char **pzErrMsg /* Put error message here if not 0 */ 4994); 4995 4996/* 4997** CAPI3REF: Enable Or Disable Extension Loading 4998** 4999** ^So as not to open security holes in older applications that are 5000** unprepared to deal with extension loading, and as a means of disabling 5001** extension loading while evaluating user-entered SQL, the following API 5002** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5003** 5004** ^Extension loading is off by default. See ticket #1863. 5005** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5006** to turn extension loading on and call it with onoff==0 to turn 5007** it back off again. 5008*/ 5009int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5010 5011/* 5012** CAPI3REF: Automatically Load Statically Linked Extensions 5013** 5014** ^This interface causes the xEntryPoint() function to be invoked for 5015** each new [database connection] that is created. The idea here is that 5016** xEntryPoint() is the entry point for a statically linked SQLite extension 5017** that is to be automatically loaded into all new database connections. 5018** 5019** ^(Even though the function prototype shows that xEntryPoint() takes 5020** no arguments and returns void, SQLite invokes xEntryPoint() with three 5021** arguments and expects and integer result as if the signature of the 5022** entry point where as follows: 5023** 5024** <blockquote><pre> 5025** int xEntryPoint( 5026** sqlite3 *db, 5027** const char **pzErrMsg, 5028** const struct sqlite3_api_routines *pThunk 5029** ); 5030** </pre></blockquote>)^ 5031** 5032** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5033** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5034** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5035** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5036** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5037** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5038** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 5039** 5040** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 5041** on the list of automatic extensions is a harmless no-op. ^No entry point 5042** will be called more than once for each database connection that is opened. 5043** 5044** See also: [sqlite3_reset_auto_extension()]. 5045*/ 5046int sqlite3_auto_extension(void (*xEntryPoint)(void)); 5047 5048/* 5049** CAPI3REF: Reset Automatic Extension Loading 5050** 5051** ^This interface disables all automatic extensions previously 5052** registered using [sqlite3_auto_extension()]. 5053*/ 5054void sqlite3_reset_auto_extension(void); 5055 5056/* 5057** The interface to the virtual-table mechanism is currently considered 5058** to be experimental. The interface might change in incompatible ways. 5059** If this is a problem for you, do not use the interface at this time. 5060** 5061** When the virtual-table mechanism stabilizes, we will declare the 5062** interface fixed, support it indefinitely, and remove this comment. 5063*/ 5064 5065/* 5066** Structures used by the virtual table interface 5067*/ 5068typedef struct sqlite3_vtab sqlite3_vtab; 5069typedef struct sqlite3_index_info sqlite3_index_info; 5070typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 5071typedef struct sqlite3_module sqlite3_module; 5072 5073/* 5074** CAPI3REF: Virtual Table Object 5075** KEYWORDS: sqlite3_module {virtual table module} 5076** 5077** This structure, sometimes called a "virtual table module", 5078** defines the implementation of a [virtual tables]. 5079** This structure consists mostly of methods for the module. 5080** 5081** ^A virtual table module is created by filling in a persistent 5082** instance of this structure and passing a pointer to that instance 5083** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 5084** ^The registration remains valid until it is replaced by a different 5085** module or until the [database connection] closes. The content 5086** of this structure must not change while it is registered with 5087** any database connection. 5088*/ 5089struct sqlite3_module { 5090 int iVersion; 5091 int (*xCreate)(sqlite3*, void *pAux, 5092 int argc, const char *const*argv, 5093 sqlite3_vtab **ppVTab, char**); 5094 int (*xConnect)(sqlite3*, void *pAux, 5095 int argc, const char *const*argv, 5096 sqlite3_vtab **ppVTab, char**); 5097 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 5098 int (*xDisconnect)(sqlite3_vtab *pVTab); 5099 int (*xDestroy)(sqlite3_vtab *pVTab); 5100 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 5101 int (*xClose)(sqlite3_vtab_cursor*); 5102 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 5103 int argc, sqlite3_value **argv); 5104 int (*xNext)(sqlite3_vtab_cursor*); 5105 int (*xEof)(sqlite3_vtab_cursor*); 5106 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 5107 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 5108 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 5109 int (*xBegin)(sqlite3_vtab *pVTab); 5110 int (*xSync)(sqlite3_vtab *pVTab); 5111 int (*xCommit)(sqlite3_vtab *pVTab); 5112 int (*xRollback)(sqlite3_vtab *pVTab); 5113 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 5114 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 5115 void **ppArg); 5116 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 5117 /* The methods above are in version 1 of the sqlite_module object. Those 5118 ** below are for version 2 and greater. */ 5119 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 5120 int (*xRelease)(sqlite3_vtab *pVTab, int); 5121 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 5122}; 5123 5124/* 5125** CAPI3REF: Virtual Table Indexing Information 5126** KEYWORDS: sqlite3_index_info 5127** 5128** The sqlite3_index_info structure and its substructures is used as part 5129** of the [virtual table] interface to 5130** pass information into and receive the reply from the [xBestIndex] 5131** method of a [virtual table module]. The fields under **Inputs** are the 5132** inputs to xBestIndex and are read-only. xBestIndex inserts its 5133** results into the **Outputs** fields. 5134** 5135** ^(The aConstraint[] array records WHERE clause constraints of the form: 5136** 5137** <blockquote>column OP expr</blockquote> 5138** 5139** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 5140** stored in aConstraint[].op using one of the 5141** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 5142** ^(The index of the column is stored in 5143** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5144** expr on the right-hand side can be evaluated (and thus the constraint 5145** is usable) and false if it cannot.)^ 5146** 5147** ^The optimizer automatically inverts terms of the form "expr OP column" 5148** and makes other simplifications to the WHERE clause in an attempt to 5149** get as many WHERE clause terms into the form shown above as possible. 5150** ^The aConstraint[] array only reports WHERE clause terms that are 5151** relevant to the particular virtual table being queried. 5152** 5153** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5154** ^Each term of aOrderBy records a column of the ORDER BY clause. 5155** 5156** The [xBestIndex] method must fill aConstraintUsage[] with information 5157** about what parameters to pass to xFilter. ^If argvIndex>0 then 5158** the right-hand side of the corresponding aConstraint[] is evaluated 5159** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5160** is true, then the constraint is assumed to be fully handled by the 5161** virtual table and is not checked again by SQLite.)^ 5162** 5163** ^The idxNum and idxPtr values are recorded and passed into the 5164** [xFilter] method. 5165** ^[sqlite3_free()] is used to free idxPtr if and only if 5166** needToFreeIdxPtr is true. 5167** 5168** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5169** the correct order to satisfy the ORDER BY clause so that no separate 5170** sorting step is required. 5171** 5172** ^The estimatedCost value is an estimate of the cost of doing the 5173** particular lookup. A full scan of a table with N entries should have 5174** a cost of N. A binary search of a table of N entries should have a 5175** cost of approximately log(N). 5176*/ 5177struct sqlite3_index_info { 5178 /* Inputs */ 5179 int nConstraint; /* Number of entries in aConstraint */ 5180 struct sqlite3_index_constraint { 5181 int iColumn; /* Column on left-hand side of constraint */ 5182 unsigned char op; /* Constraint operator */ 5183 unsigned char usable; /* True if this constraint is usable */ 5184 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5185 } *aConstraint; /* Table of WHERE clause constraints */ 5186 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5187 struct sqlite3_index_orderby { 5188 int iColumn; /* Column number */ 5189 unsigned char desc; /* True for DESC. False for ASC. */ 5190 } *aOrderBy; /* The ORDER BY clause */ 5191 /* Outputs */ 5192 struct sqlite3_index_constraint_usage { 5193 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5194 unsigned char omit; /* Do not code a test for this constraint */ 5195 } *aConstraintUsage; 5196 int idxNum; /* Number used to identify the index */ 5197 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5198 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5199 int orderByConsumed; /* True if output is already ordered */ 5200 double estimatedCost; /* Estimated cost of using this index */ 5201}; 5202 5203/* 5204** CAPI3REF: Virtual Table Constraint Operator Codes 5205** 5206** These macros defined the allowed values for the 5207** [sqlite3_index_info].aConstraint[].op field. Each value represents 5208** an operator that is part of a constraint term in the wHERE clause of 5209** a query that uses a [virtual table]. 5210*/ 5211#define SQLITE_INDEX_CONSTRAINT_EQ 2 5212#define SQLITE_INDEX_CONSTRAINT_GT 4 5213#define SQLITE_INDEX_CONSTRAINT_LE 8 5214#define SQLITE_INDEX_CONSTRAINT_LT 16 5215#define SQLITE_INDEX_CONSTRAINT_GE 32 5216#define SQLITE_INDEX_CONSTRAINT_MATCH 64 5217 5218/* 5219** CAPI3REF: Register A Virtual Table Implementation 5220** 5221** ^These routines are used to register a new [virtual table module] name. 5222** ^Module names must be registered before 5223** creating a new [virtual table] using the module and before using a 5224** preexisting [virtual table] for the module. 5225** 5226** ^The module name is registered on the [database connection] specified 5227** by the first parameter. ^The name of the module is given by the 5228** second parameter. ^The third parameter is a pointer to 5229** the implementation of the [virtual table module]. ^The fourth 5230** parameter is an arbitrary client data pointer that is passed through 5231** into the [xCreate] and [xConnect] methods of the virtual table module 5232** when a new virtual table is be being created or reinitialized. 5233** 5234** ^The sqlite3_create_module_v2() interface has a fifth parameter which 5235** is a pointer to a destructor for the pClientData. ^SQLite will 5236** invoke the destructor function (if it is not NULL) when SQLite 5237** no longer needs the pClientData pointer. ^The destructor will also 5238** be invoked if the call to sqlite3_create_module_v2() fails. 5239** ^The sqlite3_create_module() 5240** interface is equivalent to sqlite3_create_module_v2() with a NULL 5241** destructor. 5242*/ 5243int sqlite3_create_module( 5244 sqlite3 *db, /* SQLite connection to register module with */ 5245 const char *zName, /* Name of the module */ 5246 const sqlite3_module *p, /* Methods for the module */ 5247 void *pClientData /* Client data for xCreate/xConnect */ 5248); 5249int sqlite3_create_module_v2( 5250 sqlite3 *db, /* SQLite connection to register module with */ 5251 const char *zName, /* Name of the module */ 5252 const sqlite3_module *p, /* Methods for the module */ 5253 void *pClientData, /* Client data for xCreate/xConnect */ 5254 void(*xDestroy)(void*) /* Module destructor function */ 5255); 5256 5257/* 5258** CAPI3REF: Virtual Table Instance Object 5259** KEYWORDS: sqlite3_vtab 5260** 5261** Every [virtual table module] implementation uses a subclass 5262** of this object to describe a particular instance 5263** of the [virtual table]. Each subclass will 5264** be tailored to the specific needs of the module implementation. 5265** The purpose of this superclass is to define certain fields that are 5266** common to all module implementations. 5267** 5268** ^Virtual tables methods can set an error message by assigning a 5269** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 5270** take care that any prior string is freed by a call to [sqlite3_free()] 5271** prior to assigning a new string to zErrMsg. ^After the error message 5272** is delivered up to the client application, the string will be automatically 5273** freed by sqlite3_free() and the zErrMsg field will be zeroed. 5274*/ 5275struct sqlite3_vtab { 5276 const sqlite3_module *pModule; /* The module for this virtual table */ 5277 int nRef; /* NO LONGER USED */ 5278 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 5279 /* Virtual table implementations will typically add additional fields */ 5280}; 5281 5282/* 5283** CAPI3REF: Virtual Table Cursor Object 5284** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 5285** 5286** Every [virtual table module] implementation uses a subclass of the 5287** following structure to describe cursors that point into the 5288** [virtual table] and are used 5289** to loop through the virtual table. Cursors are created using the 5290** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 5291** by the [sqlite3_module.xClose | xClose] method. Cursors are used 5292** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 5293** of the module. Each module implementation will define 5294** the content of a cursor structure to suit its own needs. 5295** 5296** This superclass exists in order to define fields of the cursor that 5297** are common to all implementations. 5298*/ 5299struct sqlite3_vtab_cursor { 5300 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 5301 /* Virtual table implementations will typically add additional fields */ 5302}; 5303 5304/* 5305** CAPI3REF: Declare The Schema Of A Virtual Table 5306** 5307** ^The [xCreate] and [xConnect] methods of a 5308** [virtual table module] call this interface 5309** to declare the format (the names and datatypes of the columns) of 5310** the virtual tables they implement. 5311*/ 5312int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 5313 5314/* 5315** CAPI3REF: Overload A Function For A Virtual Table 5316** 5317** ^(Virtual tables can provide alternative implementations of functions 5318** using the [xFindFunction] method of the [virtual table module]. 5319** But global versions of those functions 5320** must exist in order to be overloaded.)^ 5321** 5322** ^(This API makes sure a global version of a function with a particular 5323** name and number of parameters exists. If no such function exists 5324** before this API is called, a new function is created.)^ ^The implementation 5325** of the new function always causes an exception to be thrown. So 5326** the new function is not good for anything by itself. Its only 5327** purpose is to be a placeholder function that can be overloaded 5328** by a [virtual table]. 5329*/ 5330int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5331 5332/* 5333** The interface to the virtual-table mechanism defined above (back up 5334** to a comment remarkably similar to this one) is currently considered 5335** to be experimental. The interface might change in incompatible ways. 5336** If this is a problem for you, do not use the interface at this time. 5337** 5338** When the virtual-table mechanism stabilizes, we will declare the 5339** interface fixed, support it indefinitely, and remove this comment. 5340*/ 5341 5342/* 5343** CAPI3REF: A Handle To An Open BLOB 5344** KEYWORDS: {BLOB handle} {BLOB handles} 5345** 5346** An instance of this object represents an open BLOB on which 5347** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5348** ^Objects of this type are created by [sqlite3_blob_open()] 5349** and destroyed by [sqlite3_blob_close()]. 5350** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5351** can be used to read or write small subsections of the BLOB. 5352** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5353*/ 5354typedef struct sqlite3_blob sqlite3_blob; 5355 5356/* 5357** CAPI3REF: Open A BLOB For Incremental I/O 5358** 5359** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5360** in row iRow, column zColumn, table zTable in database zDb; 5361** in other words, the same BLOB that would be selected by: 5362** 5363** <pre> 5364** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5365** </pre>)^ 5366** 5367** ^If the flags parameter is non-zero, then the BLOB is opened for read 5368** and write access. ^If it is zero, the BLOB is opened for read access. 5369** ^It is not possible to open a column that is part of an index or primary 5370** key for writing. ^If [foreign key constraints] are enabled, it is 5371** not possible to open a column that is part of a [child key] for writing. 5372** 5373** ^Note that the database name is not the filename that contains 5374** the database but rather the symbolic name of the database that 5375** appears after the AS keyword when the database is connected using [ATTACH]. 5376** ^For the main database file, the database name is "main". 5377** ^For TEMP tables, the database name is "temp". 5378** 5379** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 5380** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 5381** to be a null pointer.)^ 5382** ^This function sets the [database connection] error code and message 5383** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 5384** functions. ^Note that the *ppBlob variable is always initialized in a 5385** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 5386** regardless of the success or failure of this routine. 5387** 5388** ^(If the row that a BLOB handle points to is modified by an 5389** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5390** then the BLOB handle is marked as "expired". 5391** This is true if any column of the row is changed, even a column 5392** other than the one the BLOB handle is open on.)^ 5393** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5394** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5395** ^(Changes written into a BLOB prior to the BLOB expiring are not 5396** rolled back by the expiration of the BLOB. Such changes will eventually 5397** commit if the transaction continues to completion.)^ 5398** 5399** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5400** the opened blob. ^The size of a blob may not be changed by this 5401** interface. Use the [UPDATE] SQL command to change the size of a 5402** blob. 5403** 5404** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5405** and the built-in [zeroblob] SQL function can be used, if desired, 5406** to create an empty, zero-filled blob in which to read or write using 5407** this interface. 5408** 5409** To avoid a resource leak, every open [BLOB handle] should eventually 5410** be released by a call to [sqlite3_blob_close()]. 5411*/ 5412int sqlite3_blob_open( 5413 sqlite3*, 5414 const char *zDb, 5415 const char *zTable, 5416 const char *zColumn, 5417 sqlite3_int64 iRow, 5418 int flags, 5419 sqlite3_blob **ppBlob 5420); 5421 5422/* 5423** CAPI3REF: Move a BLOB Handle to a New Row 5424** 5425** ^This function is used to move an existing blob handle so that it points 5426** to a different row of the same database table. ^The new row is identified 5427** by the rowid value passed as the second argument. Only the row can be 5428** changed. ^The database, table and column on which the blob handle is open 5429** remain the same. Moving an existing blob handle to a new row can be 5430** faster than closing the existing handle and opening a new one. 5431** 5432** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5433** it must exist and there must be either a blob or text value stored in 5434** the nominated column.)^ ^If the new row is not present in the table, or if 5435** it does not contain a blob or text value, or if another error occurs, an 5436** SQLite error code is returned and the blob handle is considered aborted. 5437** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5438** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5439** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5440** always returns zero. 5441** 5442** ^This function sets the database handle error code and message. 5443*/ 5444SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5445 5446/* 5447** CAPI3REF: Close A BLOB Handle 5448** 5449** ^Closes an open [BLOB handle]. 5450** 5451** ^Closing a BLOB shall cause the current transaction to commit 5452** if there are no other BLOBs, no pending prepared statements, and the 5453** database connection is in [autocommit mode]. 5454** ^If any writes were made to the BLOB, they might be held in cache 5455** until the close operation if they will fit. 5456** 5457** ^(Closing the BLOB often forces the changes 5458** out to disk and so if any I/O errors occur, they will likely occur 5459** at the time when the BLOB is closed. Any errors that occur during 5460** closing are reported as a non-zero return value.)^ 5461** 5462** ^(The BLOB is closed unconditionally. Even if this routine returns 5463** an error code, the BLOB is still closed.)^ 5464** 5465** ^Calling this routine with a null pointer (such as would be returned 5466** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 5467*/ 5468int sqlite3_blob_close(sqlite3_blob *); 5469 5470/* 5471** CAPI3REF: Return The Size Of An Open BLOB 5472** 5473** ^Returns the size in bytes of the BLOB accessible via the 5474** successfully opened [BLOB handle] in its only argument. ^The 5475** incremental blob I/O routines can only read or overwriting existing 5476** blob content; they cannot change the size of a blob. 5477** 5478** This routine only works on a [BLOB handle] which has been created 5479** by a prior successful call to [sqlite3_blob_open()] and which has not 5480** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5481** to this routine results in undefined and probably undesirable behavior. 5482*/ 5483int sqlite3_blob_bytes(sqlite3_blob *); 5484 5485/* 5486** CAPI3REF: Read Data From A BLOB Incrementally 5487** 5488** ^(This function is used to read data from an open [BLOB handle] into a 5489** caller-supplied buffer. N bytes of data are copied into buffer Z 5490** from the open BLOB, starting at offset iOffset.)^ 5491** 5492** ^If offset iOffset is less than N bytes from the end of the BLOB, 5493** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 5494** less than zero, [SQLITE_ERROR] is returned and no data is read. 5495** ^The size of the blob (and hence the maximum value of N+iOffset) 5496** can be determined using the [sqlite3_blob_bytes()] interface. 5497** 5498** ^An attempt to read from an expired [BLOB handle] fails with an 5499** error code of [SQLITE_ABORT]. 5500** 5501** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 5502** Otherwise, an [error code] or an [extended error code] is returned.)^ 5503** 5504** This routine only works on a [BLOB handle] which has been created 5505** by a prior successful call to [sqlite3_blob_open()] and which has not 5506** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5507** to this routine results in undefined and probably undesirable behavior. 5508** 5509** See also: [sqlite3_blob_write()]. 5510*/ 5511int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 5512 5513/* 5514** CAPI3REF: Write Data Into A BLOB Incrementally 5515** 5516** ^This function is used to write data into an open [BLOB handle] from a 5517** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 5518** into the open BLOB, starting at offset iOffset. 5519** 5520** ^If the [BLOB handle] passed as the first argument was not opened for 5521** writing (the flags parameter to [sqlite3_blob_open()] was zero), 5522** this function returns [SQLITE_READONLY]. 5523** 5524** ^This function may only modify the contents of the BLOB; it is 5525** not possible to increase the size of a BLOB using this API. 5526** ^If offset iOffset is less than N bytes from the end of the BLOB, 5527** [SQLITE_ERROR] is returned and no data is written. ^If N is 5528** less than zero [SQLITE_ERROR] is returned and no data is written. 5529** The size of the BLOB (and hence the maximum value of N+iOffset) 5530** can be determined using the [sqlite3_blob_bytes()] interface. 5531** 5532** ^An attempt to write to an expired [BLOB handle] fails with an 5533** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 5534** before the [BLOB handle] expired are not rolled back by the 5535** expiration of the handle, though of course those changes might 5536** have been overwritten by the statement that expired the BLOB handle 5537** or by other independent statements. 5538** 5539** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 5540** Otherwise, an [error code] or an [extended error code] is returned.)^ 5541** 5542** This routine only works on a [BLOB handle] which has been created 5543** by a prior successful call to [sqlite3_blob_open()] and which has not 5544** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5545** to this routine results in undefined and probably undesirable behavior. 5546** 5547** See also: [sqlite3_blob_read()]. 5548*/ 5549int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 5550 5551/* 5552** CAPI3REF: Virtual File System Objects 5553** 5554** A virtual filesystem (VFS) is an [sqlite3_vfs] object 5555** that SQLite uses to interact 5556** with the underlying operating system. Most SQLite builds come with a 5557** single default VFS that is appropriate for the host computer. 5558** New VFSes can be registered and existing VFSes can be unregistered. 5559** The following interfaces are provided. 5560** 5561** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 5562** ^Names are case sensitive. 5563** ^Names are zero-terminated UTF-8 strings. 5564** ^If there is no match, a NULL pointer is returned. 5565** ^If zVfsName is NULL then the default VFS is returned. 5566** 5567** ^New VFSes are registered with sqlite3_vfs_register(). 5568** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 5569** ^The same VFS can be registered multiple times without injury. 5570** ^To make an existing VFS into the default VFS, register it again 5571** with the makeDflt flag set. If two different VFSes with the 5572** same name are registered, the behavior is undefined. If a 5573** VFS is registered with a name that is NULL or an empty string, 5574** then the behavior is undefined. 5575** 5576** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 5577** ^(If the default VFS is unregistered, another VFS is chosen as 5578** the default. The choice for the new VFS is arbitrary.)^ 5579*/ 5580sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 5581int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 5582int sqlite3_vfs_unregister(sqlite3_vfs*); 5583 5584/* 5585** CAPI3REF: Mutexes 5586** 5587** The SQLite core uses these routines for thread 5588** synchronization. Though they are intended for internal 5589** use by SQLite, code that links against SQLite is 5590** permitted to use any of these routines. 5591** 5592** The SQLite source code contains multiple implementations 5593** of these mutex routines. An appropriate implementation 5594** is selected automatically at compile-time. ^(The following 5595** implementations are available in the SQLite core: 5596** 5597** <ul> 5598** <li> SQLITE_MUTEX_PTHREADS 5599** <li> SQLITE_MUTEX_W32 5600** <li> SQLITE_MUTEX_NOOP 5601** </ul>)^ 5602** 5603** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 5604** that does no real locking and is appropriate for use in 5605** a single-threaded application. ^The SQLITE_MUTEX_PTHREADS and 5606** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 5607** and Windows. 5608** 5609** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 5610** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 5611** implementation is included with the library. In this case the 5612** application must supply a custom mutex implementation using the 5613** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 5614** before calling sqlite3_initialize() or any other public sqlite3_ 5615** function that calls sqlite3_initialize().)^ 5616** 5617** ^The sqlite3_mutex_alloc() routine allocates a new 5618** mutex and returns a pointer to it. ^If it returns NULL 5619** that means that a mutex could not be allocated. ^SQLite 5620** will unwind its stack and return an error. ^(The argument 5621** to sqlite3_mutex_alloc() is one of these integer constants: 5622** 5623** <ul> 5624** <li> SQLITE_MUTEX_FAST 5625** <li> SQLITE_MUTEX_RECURSIVE 5626** <li> SQLITE_MUTEX_STATIC_MASTER 5627** <li> SQLITE_MUTEX_STATIC_MEM 5628** <li> SQLITE_MUTEX_STATIC_MEM2 5629** <li> SQLITE_MUTEX_STATIC_PRNG 5630** <li> SQLITE_MUTEX_STATIC_LRU 5631** <li> SQLITE_MUTEX_STATIC_LRU2 5632** </ul>)^ 5633** 5634** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 5635** cause sqlite3_mutex_alloc() to create 5636** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 5637** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 5638** The mutex implementation does not need to make a distinction 5639** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 5640** not want to. ^SQLite will only request a recursive mutex in 5641** cases where it really needs one. ^If a faster non-recursive mutex 5642** implementation is available on the host platform, the mutex subsystem 5643** might return such a mutex in response to SQLITE_MUTEX_FAST. 5644** 5645** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 5646** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 5647** a pointer to a static preexisting mutex. ^Six static mutexes are 5648** used by the current version of SQLite. Future versions of SQLite 5649** may add additional static mutexes. Static mutexes are for internal 5650** use by SQLite only. Applications that use SQLite mutexes should 5651** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 5652** SQLITE_MUTEX_RECURSIVE. 5653** 5654** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 5655** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 5656** returns a different mutex on every call. ^But for the static 5657** mutex types, the same mutex is returned on every call that has 5658** the same type number. 5659** 5660** ^The sqlite3_mutex_free() routine deallocates a previously 5661** allocated dynamic mutex. ^SQLite is careful to deallocate every 5662** dynamic mutex that it allocates. The dynamic mutexes must not be in 5663** use when they are deallocated. Attempting to deallocate a static 5664** mutex results in undefined behavior. ^SQLite never deallocates 5665** a static mutex. 5666** 5667** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 5668** to enter a mutex. ^If another thread is already within the mutex, 5669** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 5670** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 5671** upon successful entry. ^(Mutexes created using 5672** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 5673** In such cases the, 5674** mutex must be exited an equal number of times before another thread 5675** can enter.)^ ^(If the same thread tries to enter any other 5676** kind of mutex more than once, the behavior is undefined. 5677** SQLite will never exhibit 5678** such behavior in its own use of mutexes.)^ 5679** 5680** ^(Some systems (for example, Windows 95) do not support the operation 5681** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 5682** will always return SQLITE_BUSY. The SQLite core only ever uses 5683** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 5684** 5685** ^The sqlite3_mutex_leave() routine exits a mutex that was 5686** previously entered by the same thread. ^(The behavior 5687** is undefined if the mutex is not currently entered by the 5688** calling thread or is not currently allocated. SQLite will 5689** never do either.)^ 5690** 5691** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 5692** sqlite3_mutex_leave() is a NULL pointer, then all three routines 5693** behave as no-ops. 5694** 5695** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 5696*/ 5697sqlite3_mutex *sqlite3_mutex_alloc(int); 5698void sqlite3_mutex_free(sqlite3_mutex*); 5699void sqlite3_mutex_enter(sqlite3_mutex*); 5700int sqlite3_mutex_try(sqlite3_mutex*); 5701void sqlite3_mutex_leave(sqlite3_mutex*); 5702 5703/* 5704** CAPI3REF: Mutex Methods Object 5705** 5706** An instance of this structure defines the low-level routines 5707** used to allocate and use mutexes. 5708** 5709** Usually, the default mutex implementations provided by SQLite are 5710** sufficient, however the user has the option of substituting a custom 5711** implementation for specialized deployments or systems for which SQLite 5712** does not provide a suitable implementation. In this case, the user 5713** creates and populates an instance of this structure to pass 5714** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 5715** Additionally, an instance of this structure can be used as an 5716** output variable when querying the system for the current mutex 5717** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 5718** 5719** ^The xMutexInit method defined by this structure is invoked as 5720** part of system initialization by the sqlite3_initialize() function. 5721** ^The xMutexInit routine is called by SQLite exactly once for each 5722** effective call to [sqlite3_initialize()]. 5723** 5724** ^The xMutexEnd method defined by this structure is invoked as 5725** part of system shutdown by the sqlite3_shutdown() function. The 5726** implementation of this method is expected to release all outstanding 5727** resources obtained by the mutex methods implementation, especially 5728** those obtained by the xMutexInit method. ^The xMutexEnd() 5729** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 5730** 5731** ^(The remaining seven methods defined by this structure (xMutexAlloc, 5732** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 5733** xMutexNotheld) implement the following interfaces (respectively): 5734** 5735** <ul> 5736** <li> [sqlite3_mutex_alloc()] </li> 5737** <li> [sqlite3_mutex_free()] </li> 5738** <li> [sqlite3_mutex_enter()] </li> 5739** <li> [sqlite3_mutex_try()] </li> 5740** <li> [sqlite3_mutex_leave()] </li> 5741** <li> [sqlite3_mutex_held()] </li> 5742** <li> [sqlite3_mutex_notheld()] </li> 5743** </ul>)^ 5744** 5745** The only difference is that the public sqlite3_XXX functions enumerated 5746** above silently ignore any invocations that pass a NULL pointer instead 5747** of a valid mutex handle. The implementations of the methods defined 5748** by this structure are not required to handle this case, the results 5749** of passing a NULL pointer instead of a valid mutex handle are undefined 5750** (i.e. it is acceptable to provide an implementation that segfaults if 5751** it is passed a NULL pointer). 5752** 5753** The xMutexInit() method must be threadsafe. ^It must be harmless to 5754** invoke xMutexInit() multiple times within the same process and without 5755** intervening calls to xMutexEnd(). Second and subsequent calls to 5756** xMutexInit() must be no-ops. 5757** 5758** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 5759** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 5760** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 5761** memory allocation for a fast or recursive mutex. 5762** 5763** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 5764** called, but only if the prior call to xMutexInit returned SQLITE_OK. 5765** If xMutexInit fails in any way, it is expected to clean up after itself 5766** prior to returning. 5767*/ 5768typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 5769struct sqlite3_mutex_methods { 5770 int (*xMutexInit)(void); 5771 int (*xMutexEnd)(void); 5772 sqlite3_mutex *(*xMutexAlloc)(int); 5773 void (*xMutexFree)(sqlite3_mutex *); 5774 void (*xMutexEnter)(sqlite3_mutex *); 5775 int (*xMutexTry)(sqlite3_mutex *); 5776 void (*xMutexLeave)(sqlite3_mutex *); 5777 int (*xMutexHeld)(sqlite3_mutex *); 5778 int (*xMutexNotheld)(sqlite3_mutex *); 5779}; 5780 5781/* 5782** CAPI3REF: Mutex Verification Routines 5783** 5784** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 5785** are intended for use inside assert() statements. ^The SQLite core 5786** never uses these routines except inside an assert() and applications 5787** are advised to follow the lead of the core. ^The SQLite core only 5788** provides implementations for these routines when it is compiled 5789** with the SQLITE_DEBUG flag. ^External mutex implementations 5790** are only required to provide these routines if SQLITE_DEBUG is 5791** defined and if NDEBUG is not defined. 5792** 5793** ^These routines should return true if the mutex in their argument 5794** is held or not held, respectively, by the calling thread. 5795** 5796** ^The implementation is not required to provide versions of these 5797** routines that actually work. If the implementation does not provide working 5798** versions of these routines, it should at least provide stubs that always 5799** return true so that one does not get spurious assertion failures. 5800** 5801** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 5802** the routine should return 1. This seems counter-intuitive since 5803** clearly the mutex cannot be held if it does not exist. But 5804** the reason the mutex does not exist is because the build is not 5805** using mutexes. And we do not want the assert() containing the 5806** call to sqlite3_mutex_held() to fail, so a non-zero return is 5807** the appropriate thing to do. ^The sqlite3_mutex_notheld() 5808** interface should also return 1 when given a NULL pointer. 5809*/ 5810#ifndef NDEBUG 5811int sqlite3_mutex_held(sqlite3_mutex*); 5812int sqlite3_mutex_notheld(sqlite3_mutex*); 5813#endif 5814 5815/* 5816** CAPI3REF: Mutex Types 5817** 5818** The [sqlite3_mutex_alloc()] interface takes a single argument 5819** which is one of these integer constants. 5820** 5821** The set of static mutexes may change from one SQLite release to the 5822** next. Applications that override the built-in mutex logic must be 5823** prepared to accommodate additional static mutexes. 5824*/ 5825#define SQLITE_MUTEX_FAST 0 5826#define SQLITE_MUTEX_RECURSIVE 1 5827#define SQLITE_MUTEX_STATIC_MASTER 2 5828#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 5829#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 5830#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 5831#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 5832#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 5833#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 5834#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 5835 5836/* 5837** CAPI3REF: Retrieve the mutex for a database connection 5838** 5839** ^This interface returns a pointer the [sqlite3_mutex] object that 5840** serializes access to the [database connection] given in the argument 5841** when the [threading mode] is Serialized. 5842** ^If the [threading mode] is Single-thread or Multi-thread then this 5843** routine returns a NULL pointer. 5844*/ 5845sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 5846 5847/* 5848** CAPI3REF: Low-Level Control Of Database Files 5849** 5850** ^The [sqlite3_file_control()] interface makes a direct call to the 5851** xFileControl method for the [sqlite3_io_methods] object associated 5852** with a particular database identified by the second argument. ^The 5853** name of the database is "main" for the main database or "temp" for the 5854** TEMP database, or the name that appears after the AS keyword for 5855** databases that are added using the [ATTACH] SQL command. 5856** ^A NULL pointer can be used in place of "main" to refer to the 5857** main database file. 5858** ^The third and fourth parameters to this routine 5859** are passed directly through to the second and third parameters of 5860** the xFileControl method. ^The return value of the xFileControl 5861** method becomes the return value of this routine. 5862** 5863** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 5864** a pointer to the underlying [sqlite3_file] object to be written into 5865** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 5866** case is a short-circuit path which does not actually invoke the 5867** underlying sqlite3_io_methods.xFileControl method. 5868** 5869** ^If the second parameter (zDbName) does not match the name of any 5870** open database file, then SQLITE_ERROR is returned. ^This error 5871** code is not remembered and will not be recalled by [sqlite3_errcode()] 5872** or [sqlite3_errmsg()]. The underlying xFileControl method might 5873** also return SQLITE_ERROR. There is no way to distinguish between 5874** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5875** xFileControl method. 5876** 5877** See also: [SQLITE_FCNTL_LOCKSTATE] 5878*/ 5879int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5880 5881/* 5882** CAPI3REF: Testing Interface 5883** 5884** ^The sqlite3_test_control() interface is used to read out internal 5885** state of SQLite and to inject faults into SQLite for testing 5886** purposes. ^The first parameter is an operation code that determines 5887** the number, meaning, and operation of all subsequent parameters. 5888** 5889** This interface is not for use by applications. It exists solely 5890** for verifying the correct operation of the SQLite library. Depending 5891** on how the SQLite library is compiled, this interface might not exist. 5892** 5893** The details of the operation codes, their meanings, the parameters 5894** they take, and what they do are all subject to change without notice. 5895** Unlike most of the SQLite API, this function is not guaranteed to 5896** operate consistently from one release to the next. 5897*/ 5898int sqlite3_test_control(int op, ...); 5899 5900/* 5901** CAPI3REF: Testing Interface Operation Codes 5902** 5903** These constants are the valid operation code parameters used 5904** as the first argument to [sqlite3_test_control()]. 5905** 5906** These parameters and their meanings are subject to change 5907** without notice. These values are for testing purposes only. 5908** Applications should not use any of these parameters or the 5909** [sqlite3_test_control()] interface. 5910*/ 5911#define SQLITE_TESTCTRL_FIRST 5 5912#define SQLITE_TESTCTRL_PRNG_SAVE 5 5913#define SQLITE_TESTCTRL_PRNG_RESTORE 6 5914#define SQLITE_TESTCTRL_PRNG_RESET 7 5915#define SQLITE_TESTCTRL_BITVEC_TEST 8 5916#define SQLITE_TESTCTRL_FAULT_INSTALL 9 5917#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5918#define SQLITE_TESTCTRL_PENDING_BYTE 11 5919#define SQLITE_TESTCTRL_ASSERT 12 5920#define SQLITE_TESTCTRL_ALWAYS 13 5921#define SQLITE_TESTCTRL_RESERVE 14 5922#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 5923#define SQLITE_TESTCTRL_ISKEYWORD 16 5924#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 5925#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 5926#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 5927#define SQLITE_TESTCTRL_LAST 19 5928 5929/* 5930** CAPI3REF: SQLite Runtime Status 5931** 5932** ^This interface is used to retrieve runtime status information 5933** about the performance of SQLite, and optionally to reset various 5934** highwater marks. ^The first argument is an integer code for 5935** the specific parameter to measure. ^(Recognized integer codes 5936** are of the form [status parameters | SQLITE_STATUS_...].)^ 5937** ^The current value of the parameter is returned into *pCurrent. 5938** ^The highest recorded value is returned in *pHighwater. ^If the 5939** resetFlag is true, then the highest record value is reset after 5940** *pHighwater is written. ^(Some parameters do not record the highest 5941** value. For those parameters 5942** nothing is written into *pHighwater and the resetFlag is ignored.)^ 5943** ^(Other parameters record only the highwater mark and not the current 5944** value. For these latter parameters nothing is written into *pCurrent.)^ 5945** 5946** ^The sqlite3_status() routine returns SQLITE_OK on success and a 5947** non-zero [error code] on failure. 5948** 5949** This routine is threadsafe but is not atomic. This routine can be 5950** called while other threads are running the same or different SQLite 5951** interfaces. However the values returned in *pCurrent and 5952** *pHighwater reflect the status of SQLite at different points in time 5953** and it is possible that another thread might change the parameter 5954** in between the times when *pCurrent and *pHighwater are written. 5955** 5956** See also: [sqlite3_db_status()] 5957*/ 5958int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 5959 5960 5961/* 5962** CAPI3REF: Status Parameters 5963** KEYWORDS: {status parameters} 5964** 5965** These integer constants designate various run-time status parameters 5966** that can be returned by [sqlite3_status()]. 5967** 5968** <dl> 5969** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 5970** <dd>This parameter is the current amount of memory checked out 5971** using [sqlite3_malloc()], either directly or indirectly. The 5972** figure includes calls made to [sqlite3_malloc()] by the application 5973** and internal memory usage by the SQLite library. Scratch memory 5974** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 5975** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 5976** this parameter. The amount returned is the sum of the allocation 5977** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 5978** 5979** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 5980** <dd>This parameter records the largest memory allocation request 5981** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 5982** internal equivalents). Only the value returned in the 5983** *pHighwater parameter to [sqlite3_status()] is of interest. 5984** The value written into the *pCurrent parameter is undefined.</dd>)^ 5985** 5986** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 5987** <dd>This parameter records the number of separate memory allocations 5988** currently checked out.</dd>)^ 5989** 5990** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 5991** <dd>This parameter returns the number of pages used out of the 5992** [pagecache memory allocator] that was configured using 5993** [SQLITE_CONFIG_PAGECACHE]. The 5994** value returned is in pages, not in bytes.</dd>)^ 5995** 5996** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 5997** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5998** <dd>This parameter returns the number of bytes of page cache 5999** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 6000** buffer and where forced to overflow to [sqlite3_malloc()]. The 6001** returned value includes allocations that overflowed because they 6002** where too large (they were larger than the "sz" parameter to 6003** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 6004** no space was left in the page cache.</dd>)^ 6005** 6006** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 6007** <dd>This parameter records the largest memory allocation request 6008** handed to [pagecache memory allocator]. Only the value returned in the 6009** *pHighwater parameter to [sqlite3_status()] is of interest. 6010** The value written into the *pCurrent parameter is undefined.</dd>)^ 6011** 6012** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 6013** <dd>This parameter returns the number of allocations used out of the 6014** [scratch memory allocator] configured using 6015** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 6016** in bytes. Since a single thread may only have one scratch allocation 6017** outstanding at time, this parameter also reports the number of threads 6018** using scratch memory at the same time.</dd>)^ 6019** 6020** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 6021** <dd>This parameter returns the number of bytes of scratch memory 6022** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 6023** buffer and where forced to overflow to [sqlite3_malloc()]. The values 6024** returned include overflows because the requested allocation was too 6025** larger (that is, because the requested allocation was larger than the 6026** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 6027** slots were available. 6028** </dd>)^ 6029** 6030** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 6031** <dd>This parameter records the largest memory allocation request 6032** handed to [scratch memory allocator]. Only the value returned in the 6033** *pHighwater parameter to [sqlite3_status()] is of interest. 6034** The value written into the *pCurrent parameter is undefined.</dd>)^ 6035** 6036** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 6037** <dd>This parameter records the deepest parser stack. It is only 6038** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 6039** </dl> 6040** 6041** New status parameters may be added from time to time. 6042*/ 6043#define SQLITE_STATUS_MEMORY_USED 0 6044#define SQLITE_STATUS_PAGECACHE_USED 1 6045#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 6046#define SQLITE_STATUS_SCRATCH_USED 3 6047#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 6048#define SQLITE_STATUS_MALLOC_SIZE 5 6049#define SQLITE_STATUS_PARSER_STACK 6 6050#define SQLITE_STATUS_PAGECACHE_SIZE 7 6051#define SQLITE_STATUS_SCRATCH_SIZE 8 6052#define SQLITE_STATUS_MALLOC_COUNT 9 6053 6054/* 6055** CAPI3REF: Database Connection Status 6056** 6057** ^This interface is used to retrieve runtime status information 6058** about a single [database connection]. ^The first argument is the 6059** database connection object to be interrogated. ^The second argument 6060** is an integer constant, taken from the set of 6061** [SQLITE_DBSTATUS options], that 6062** determines the parameter to interrogate. The set of 6063** [SQLITE_DBSTATUS options] is likely 6064** to grow in future releases of SQLite. 6065** 6066** ^The current value of the requested parameter is written into *pCur 6067** and the highest instantaneous value is written into *pHiwtr. ^If 6068** the resetFlg is true, then the highest instantaneous value is 6069** reset back down to the current value. 6070** 6071** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 6072** non-zero [error code] on failure. 6073** 6074** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 6075*/ 6076int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 6077 6078/* 6079** CAPI3REF: Status Parameters for database connections 6080** KEYWORDS: {SQLITE_DBSTATUS options} 6081** 6082** These constants are the available integer "verbs" that can be passed as 6083** the second argument to the [sqlite3_db_status()] interface. 6084** 6085** New verbs may be added in future releases of SQLite. Existing verbs 6086** might be discontinued. Applications should check the return code from 6087** [sqlite3_db_status()] to make sure that the call worked. 6088** The [sqlite3_db_status()] interface will return a non-zero error code 6089** if a discontinued or unsupported verb is invoked. 6090** 6091** <dl> 6092** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 6093** <dd>This parameter returns the number of lookaside memory slots currently 6094** checked out.</dd>)^ 6095** 6096** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 6097** <dd>This parameter returns the number malloc attempts that were 6098** satisfied using lookaside memory. Only the high-water value is meaningful; 6099** the current value is always zero.)^ 6100** 6101** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 6102** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 6103** <dd>This parameter returns the number malloc attempts that might have 6104** been satisfied using lookaside memory but failed due to the amount of 6105** memory requested being larger than the lookaside slot size. 6106** Only the high-water value is meaningful; 6107** the current value is always zero.)^ 6108** 6109** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 6110** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 6111** <dd>This parameter returns the number malloc attempts that might have 6112** been satisfied using lookaside memory but failed due to all lookaside 6113** memory already being in use. 6114** Only the high-water value is meaningful; 6115** the current value is always zero.)^ 6116** 6117** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 6118** <dd>This parameter returns the approximate number of of bytes of heap 6119** memory used by all pager caches associated with the database connection.)^ 6120** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 6121** 6122** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 6123** <dd>This parameter returns the approximate number of of bytes of heap 6124** memory used to store the schema for all databases associated 6125** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 6126** ^The full amount of memory used by the schemas is reported, even if the 6127** schema memory is shared with other database connections due to 6128** [shared cache mode] being enabled. 6129** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 6130** 6131** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 6132** <dd>This parameter returns the approximate number of of bytes of heap 6133** and lookaside memory used by all prepared statements associated with 6134** the database connection.)^ 6135** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 6136** </dd> 6137** 6138** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 6139** <dd>This parameter returns the number of pager cache hits that have 6140** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 6141** is always 0. 6142** </dd> 6143** 6144** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6145** <dd>This parameter returns the number of pager cache misses that have 6146** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6147** is always 0. 6148** </dd> 6149** 6150** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 6151** <dd>This parameter returns the number of dirty cache entries that have 6152** been written to disk. Specifically, the number of pages written to the 6153** wal file in wal mode databases, or the number of pages written to the 6154** database file in rollback mode databases. Any pages written as part of 6155** transaction rollback or database recovery operations are not included. 6156** If an IO or other error occurs while writing a page to disk, the effect 6157** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 6158** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 6159** </dd> 6160** </dl> 6161*/ 6162#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6163#define SQLITE_DBSTATUS_CACHE_USED 1 6164#define SQLITE_DBSTATUS_SCHEMA_USED 2 6165#define SQLITE_DBSTATUS_STMT_USED 3 6166#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6167#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6168#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 6169#define SQLITE_DBSTATUS_CACHE_HIT 7 6170#define SQLITE_DBSTATUS_CACHE_MISS 8 6171#define SQLITE_DBSTATUS_CACHE_WRITE 9 6172#define SQLITE_DBSTATUS_MAX 9 /* Largest defined DBSTATUS */ 6173 6174 6175/* 6176** CAPI3REF: Prepared Statement Status 6177** 6178** ^(Each prepared statement maintains various 6179** [SQLITE_STMTSTATUS counters] that measure the number 6180** of times it has performed specific operations.)^ These counters can 6181** be used to monitor the performance characteristics of the prepared 6182** statements. For example, if the number of table steps greatly exceeds 6183** the number of table searches or result rows, that would tend to indicate 6184** that the prepared statement is using a full table scan rather than 6185** an index. 6186** 6187** ^(This interface is used to retrieve and reset counter values from 6188** a [prepared statement]. The first argument is the prepared statement 6189** object to be interrogated. The second argument 6190** is an integer code for a specific [SQLITE_STMTSTATUS counter] 6191** to be interrogated.)^ 6192** ^The current value of the requested counter is returned. 6193** ^If the resetFlg is true, then the counter is reset to zero after this 6194** interface call returns. 6195** 6196** See also: [sqlite3_status()] and [sqlite3_db_status()]. 6197*/ 6198int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 6199 6200/* 6201** CAPI3REF: Status Parameters for prepared statements 6202** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 6203** 6204** These preprocessor macros define integer codes that name counter 6205** values associated with the [sqlite3_stmt_status()] interface. 6206** The meanings of the various counters are as follows: 6207** 6208** <dl> 6209** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 6210** <dd>^This is the number of times that SQLite has stepped forward in 6211** a table as part of a full table scan. Large numbers for this counter 6212** may indicate opportunities for performance improvement through 6213** careful use of indices.</dd> 6214** 6215** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 6216** <dd>^This is the number of sort operations that have occurred. 6217** A non-zero value in this counter may indicate an opportunity to 6218** improvement performance through careful use of indices.</dd> 6219** 6220** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 6221** <dd>^This is the number of rows inserted into transient indices that 6222** were created automatically in order to help joins run faster. 6223** A non-zero value in this counter may indicate an opportunity to 6224** improvement performance by adding permanent indices that do not 6225** need to be reinitialized each time the statement is run.</dd> 6226** </dl> 6227*/ 6228#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 6229#define SQLITE_STMTSTATUS_SORT 2 6230#define SQLITE_STMTSTATUS_AUTOINDEX 3 6231 6232/* 6233** CAPI3REF: Custom Page Cache Object 6234** 6235** The sqlite3_pcache type is opaque. It is implemented by 6236** the pluggable module. The SQLite core has no knowledge of 6237** its size or internal structure and never deals with the 6238** sqlite3_pcache object except by holding and passing pointers 6239** to the object. 6240** 6241** See [sqlite3_pcache_methods2] for additional information. 6242*/ 6243typedef struct sqlite3_pcache sqlite3_pcache; 6244 6245/* 6246** CAPI3REF: Custom Page Cache Object 6247** 6248** The sqlite3_pcache_page object represents a single page in the 6249** page cache. The page cache will allocate instances of this 6250** object. Various methods of the page cache use pointers to instances 6251** of this object as parameters or as their return value. 6252** 6253** See [sqlite3_pcache_methods2] for additional information. 6254*/ 6255typedef struct sqlite3_pcache_page sqlite3_pcache_page; 6256struct sqlite3_pcache_page { 6257 void *pBuf; /* The content of the page */ 6258 void *pExtra; /* Extra information associated with the page */ 6259}; 6260 6261/* 6262** CAPI3REF: Application Defined Page Cache. 6263** KEYWORDS: {page cache} 6264** 6265** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 6266** register an alternative page cache implementation by passing in an 6267** instance of the sqlite3_pcache_methods2 structure.)^ 6268** In many applications, most of the heap memory allocated by 6269** SQLite is used for the page cache. 6270** By implementing a 6271** custom page cache using this API, an application can better control 6272** the amount of memory consumed by SQLite, the way in which 6273** that memory is allocated and released, and the policies used to 6274** determine exactly which parts of a database file are cached and for 6275** how long. 6276** 6277** The alternative page cache mechanism is an 6278** extreme measure that is only needed by the most demanding applications. 6279** The built-in page cache is recommended for most uses. 6280** 6281** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 6282** internal buffer by SQLite within the call to [sqlite3_config]. Hence 6283** the application may discard the parameter after the call to 6284** [sqlite3_config()] returns.)^ 6285** 6286** [[the xInit() page cache method]] 6287** ^(The xInit() method is called once for each effective 6288** call to [sqlite3_initialize()])^ 6289** (usually only once during the lifetime of the process). ^(The xInit() 6290** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 6291** The intent of the xInit() method is to set up global data structures 6292** required by the custom page cache implementation. 6293** ^(If the xInit() method is NULL, then the 6294** built-in default page cache is used instead of the application defined 6295** page cache.)^ 6296** 6297** [[the xShutdown() page cache method]] 6298** ^The xShutdown() method is called by [sqlite3_shutdown()]. 6299** It can be used to clean up 6300** any outstanding resources before process shutdown, if required. 6301** ^The xShutdown() method may be NULL. 6302** 6303** ^SQLite automatically serializes calls to the xInit method, 6304** so the xInit method need not be threadsafe. ^The 6305** xShutdown method is only called from [sqlite3_shutdown()] so it does 6306** not need to be threadsafe either. All other methods must be threadsafe 6307** in multithreaded applications. 6308** 6309** ^SQLite will never invoke xInit() more than once without an intervening 6310** call to xShutdown(). 6311** 6312** [[the xCreate() page cache methods]] 6313** ^SQLite invokes the xCreate() method to construct a new cache instance. 6314** SQLite will typically create one cache instance for each open database file, 6315** though this is not guaranteed. ^The 6316** first parameter, szPage, is the size in bytes of the pages that must 6317** be allocated by the cache. ^szPage will always a power of two. ^The 6318** second parameter szExtra is a number of bytes of extra storage 6319** associated with each page cache entry. ^The szExtra parameter will 6320** a number less than 250. SQLite will use the 6321** extra szExtra bytes on each page to store metadata about the underlying 6322** database page on disk. The value passed into szExtra depends 6323** on the SQLite version, the target platform, and how SQLite was compiled. 6324** ^The third argument to xCreate(), bPurgeable, is true if the cache being 6325** created will be used to cache database pages of a file stored on disk, or 6326** false if it is used for an in-memory database. The cache implementation 6327** does not have to do anything special based with the value of bPurgeable; 6328** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 6329** never invoke xUnpin() except to deliberately delete a page. 6330** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 6331** false will always have the "discard" flag set to true. 6332** ^Hence, a cache created with bPurgeable false will 6333** never contain any unpinned pages. 6334** 6335** [[the xCachesize() page cache method]] 6336** ^(The xCachesize() method may be called at any time by SQLite to set the 6337** suggested maximum cache-size (number of pages stored by) the cache 6338** instance passed as the first argument. This is the value configured using 6339** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 6340** parameter, the implementation is not required to do anything with this 6341** value; it is advisory only. 6342** 6343** [[the xPagecount() page cache methods]] 6344** The xPagecount() method must return the number of pages currently 6345** stored in the cache, both pinned and unpinned. 6346** 6347** [[the xFetch() page cache methods]] 6348** The xFetch() method locates a page in the cache and returns a pointer to 6349** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 6350** The pBuf element of the returned sqlite3_pcache_page object will be a 6351** pointer to a buffer of szPage bytes used to store the content of a 6352** single database page. The pExtra element of sqlite3_pcache_page will be 6353** a pointer to the szExtra bytes of extra storage that SQLite has requested 6354** for each entry in the page cache. 6355** 6356** The page to be fetched is determined by the key. ^The minimum key value 6357** is 1. After it has been retrieved using xFetch, the page is considered 6358** to be "pinned". 6359** 6360** If the requested page is already in the page cache, then the page cache 6361** implementation must return a pointer to the page buffer with its content 6362** intact. If the requested page is not already in the cache, then the 6363** cache implementation should use the value of the createFlag 6364** parameter to help it determined what action to take: 6365** 6366** <table border=1 width=85% align=center> 6367** <tr><th> createFlag <th> Behaviour when page is not already in cache 6368** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6369** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6370** Otherwise return NULL. 6371** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6372** NULL if allocating a new page is effectively impossible. 6373** </table> 6374** 6375** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6376** will only use a createFlag of 2 after a prior call with a createFlag of 1 6377** failed.)^ In between the to xFetch() calls, SQLite may 6378** attempt to unpin one or more cache pages by spilling the content of 6379** pinned pages to disk and synching the operating system disk cache. 6380** 6381** [[the xUnpin() page cache method]] 6382** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6383** as its second argument. If the third parameter, discard, is non-zero, 6384** then the page must be evicted from the cache. 6385** ^If the discard parameter is 6386** zero, then the page may be discarded or retained at the discretion of 6387** page cache implementation. ^The page cache implementation 6388** may choose to evict unpinned pages at any time. 6389** 6390** The cache must not perform any reference counting. A single 6391** call to xUnpin() unpins the page regardless of the number of prior calls 6392** to xFetch(). 6393** 6394** [[the xRekey() page cache methods]] 6395** The xRekey() method is used to change the key value associated with the 6396** page passed as the second argument. If the cache 6397** previously contains an entry associated with newKey, it must be 6398** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6399** to be pinned. 6400** 6401** When SQLite calls the xTruncate() method, the cache must discard all 6402** existing cache entries with page numbers (keys) greater than or equal 6403** to the value of the iLimit parameter passed to xTruncate(). If any 6404** of these pages are pinned, they are implicitly unpinned, meaning that 6405** they can be safely discarded. 6406** 6407** [[the xDestroy() page cache method]] 6408** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6409** All resources associated with the specified cache should be freed. ^After 6410** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6411** handle invalid, and will not use it with any other sqlite3_pcache_methods2 6412** functions. 6413** 6414** [[the xShrink() page cache method]] 6415** ^SQLite invokes the xShrink() method when it wants the page cache to 6416** free up as much of heap memory as possible. The page cache implementation 6417** is not obligated to free any memory, but well-behaved implementations should 6418** do their best. 6419*/ 6420typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 6421struct sqlite3_pcache_methods2 { 6422 int iVersion; 6423 void *pArg; 6424 int (*xInit)(void*); 6425 void (*xShutdown)(void*); 6426 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 6427 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6428 int (*xPagecount)(sqlite3_pcache*); 6429 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6430 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 6431 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 6432 unsigned oldKey, unsigned newKey); 6433 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6434 void (*xDestroy)(sqlite3_pcache*); 6435 void (*xShrink)(sqlite3_pcache*); 6436}; 6437 6438/* 6439** This is the obsolete pcache_methods object that has now been replaced 6440** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 6441** retained in the header file for backwards compatibility only. 6442*/ 6443typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 6444struct sqlite3_pcache_methods { 6445 void *pArg; 6446 int (*xInit)(void*); 6447 void (*xShutdown)(void*); 6448 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 6449 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6450 int (*xPagecount)(sqlite3_pcache*); 6451 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6452 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 6453 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 6454 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6455 void (*xDestroy)(sqlite3_pcache*); 6456}; 6457 6458 6459/* 6460** CAPI3REF: Online Backup Object 6461** 6462** The sqlite3_backup object records state information about an ongoing 6463** online backup operation. ^The sqlite3_backup object is created by 6464** a call to [sqlite3_backup_init()] and is destroyed by a call to 6465** [sqlite3_backup_finish()]. 6466** 6467** See Also: [Using the SQLite Online Backup API] 6468*/ 6469typedef struct sqlite3_backup sqlite3_backup; 6470 6471/* 6472** CAPI3REF: Online Backup API. 6473** 6474** The backup API copies the content of one database into another. 6475** It is useful either for creating backups of databases or 6476** for copying in-memory databases to or from persistent files. 6477** 6478** See Also: [Using the SQLite Online Backup API] 6479** 6480** ^SQLite holds a write transaction open on the destination database file 6481** for the duration of the backup operation. 6482** ^The source database is read-locked only while it is being read; 6483** it is not locked continuously for the entire backup operation. 6484** ^Thus, the backup may be performed on a live source database without 6485** preventing other database connections from 6486** reading or writing to the source database while the backup is underway. 6487** 6488** ^(To perform a backup operation: 6489** <ol> 6490** <li><b>sqlite3_backup_init()</b> is called once to initialize the 6491** backup, 6492** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 6493** the data between the two databases, and finally 6494** <li><b>sqlite3_backup_finish()</b> is called to release all resources 6495** associated with the backup operation. 6496** </ol>)^ 6497** There should be exactly one call to sqlite3_backup_finish() for each 6498** successful call to sqlite3_backup_init(). 6499** 6500** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 6501** 6502** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 6503** [database connection] associated with the destination database 6504** and the database name, respectively. 6505** ^The database name is "main" for the main database, "temp" for the 6506** temporary database, or the name specified after the AS keyword in 6507** an [ATTACH] statement for an attached database. 6508** ^The S and M arguments passed to 6509** sqlite3_backup_init(D,N,S,M) identify the [database connection] 6510** and database name of the source database, respectively. 6511** ^The source and destination [database connections] (parameters S and D) 6512** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 6513** an error. 6514** 6515** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 6516** returned and an error code and error message are stored in the 6517** destination [database connection] D. 6518** ^The error code and message for the failed call to sqlite3_backup_init() 6519** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 6520** [sqlite3_errmsg16()] functions. 6521** ^A successful call to sqlite3_backup_init() returns a pointer to an 6522** [sqlite3_backup] object. 6523** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 6524** sqlite3_backup_finish() functions to perform the specified backup 6525** operation. 6526** 6527** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 6528** 6529** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 6530** the source and destination databases specified by [sqlite3_backup] object B. 6531** ^If N is negative, all remaining source pages are copied. 6532** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 6533** are still more pages to be copied, then the function returns [SQLITE_OK]. 6534** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 6535** from source to destination, then it returns [SQLITE_DONE]. 6536** ^If an error occurs while running sqlite3_backup_step(B,N), 6537** then an [error code] is returned. ^As well as [SQLITE_OK] and 6538** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 6539** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 6540** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 6541** 6542** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 6543** <ol> 6544** <li> the destination database was opened read-only, or 6545** <li> the destination database is using write-ahead-log journaling 6546** and the destination and source page sizes differ, or 6547** <li> the destination database is an in-memory database and the 6548** destination and source page sizes differ. 6549** </ol>)^ 6550** 6551** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 6552** the [sqlite3_busy_handler | busy-handler function] 6553** is invoked (if one is specified). ^If the 6554** busy-handler returns non-zero before the lock is available, then 6555** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 6556** sqlite3_backup_step() can be retried later. ^If the source 6557** [database connection] 6558** is being used to write to the source database when sqlite3_backup_step() 6559** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 6560** case the call to sqlite3_backup_step() can be retried later on. ^(If 6561** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 6562** [SQLITE_READONLY] is returned, then 6563** there is no point in retrying the call to sqlite3_backup_step(). These 6564** errors are considered fatal.)^ The application must accept 6565** that the backup operation has failed and pass the backup operation handle 6566** to the sqlite3_backup_finish() to release associated resources. 6567** 6568** ^The first call to sqlite3_backup_step() obtains an exclusive lock 6569** on the destination file. ^The exclusive lock is not released until either 6570** sqlite3_backup_finish() is called or the backup operation is complete 6571** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 6572** sqlite3_backup_step() obtains a [shared lock] on the source database that 6573** lasts for the duration of the sqlite3_backup_step() call. 6574** ^Because the source database is not locked between calls to 6575** sqlite3_backup_step(), the source database may be modified mid-way 6576** through the backup process. ^If the source database is modified by an 6577** external process or via a database connection other than the one being 6578** used by the backup operation, then the backup will be automatically 6579** restarted by the next call to sqlite3_backup_step(). ^If the source 6580** database is modified by the using the same database connection as is used 6581** by the backup operation, then the backup database is automatically 6582** updated at the same time. 6583** 6584** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 6585** 6586** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 6587** application wishes to abandon the backup operation, the application 6588** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 6589** ^The sqlite3_backup_finish() interfaces releases all 6590** resources associated with the [sqlite3_backup] object. 6591** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 6592** active write-transaction on the destination database is rolled back. 6593** The [sqlite3_backup] object is invalid 6594** and may not be used following a call to sqlite3_backup_finish(). 6595** 6596** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 6597** sqlite3_backup_step() errors occurred, regardless or whether or not 6598** sqlite3_backup_step() completed. 6599** ^If an out-of-memory condition or IO error occurred during any prior 6600** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 6601** sqlite3_backup_finish() returns the corresponding [error code]. 6602** 6603** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 6604** is not a permanent error and does not affect the return value of 6605** sqlite3_backup_finish(). 6606** 6607** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]] 6608** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 6609** 6610** ^Each call to sqlite3_backup_step() sets two values inside 6611** the [sqlite3_backup] object: the number of pages still to be backed 6612** up and the total number of pages in the source database file. 6613** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 6614** retrieve these two values, respectively. 6615** 6616** ^The values returned by these functions are only updated by 6617** sqlite3_backup_step(). ^If the source database is modified during a backup 6618** operation, then the values are not updated to account for any extra 6619** pages that need to be updated or the size of the source database file 6620** changing. 6621** 6622** <b>Concurrent Usage of Database Handles</b> 6623** 6624** ^The source [database connection] may be used by the application for other 6625** purposes while a backup operation is underway or being initialized. 6626** ^If SQLite is compiled and configured to support threadsafe database 6627** connections, then the source database connection may be used concurrently 6628** from within other threads. 6629** 6630** However, the application must guarantee that the destination 6631** [database connection] is not passed to any other API (by any thread) after 6632** sqlite3_backup_init() is called and before the corresponding call to 6633** sqlite3_backup_finish(). SQLite does not currently check to see 6634** if the application incorrectly accesses the destination [database connection] 6635** and so no error code is reported, but the operations may malfunction 6636** nevertheless. Use of the destination database connection while a 6637** backup is in progress might also also cause a mutex deadlock. 6638** 6639** If running in [shared cache mode], the application must 6640** guarantee that the shared cache used by the destination database 6641** is not accessed while the backup is running. In practice this means 6642** that the application must guarantee that the disk file being 6643** backed up to is not accessed by any connection within the process, 6644** not just the specific connection that was passed to sqlite3_backup_init(). 6645** 6646** The [sqlite3_backup] object itself is partially threadsafe. Multiple 6647** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 6648** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 6649** APIs are not strictly speaking threadsafe. If they are invoked at the 6650** same time as another thread is invoking sqlite3_backup_step() it is 6651** possible that they return invalid values. 6652*/ 6653sqlite3_backup *sqlite3_backup_init( 6654 sqlite3 *pDest, /* Destination database handle */ 6655 const char *zDestName, /* Destination database name */ 6656 sqlite3 *pSource, /* Source database handle */ 6657 const char *zSourceName /* Source database name */ 6658); 6659int sqlite3_backup_step(sqlite3_backup *p, int nPage); 6660int sqlite3_backup_finish(sqlite3_backup *p); 6661int sqlite3_backup_remaining(sqlite3_backup *p); 6662int sqlite3_backup_pagecount(sqlite3_backup *p); 6663 6664/* 6665** CAPI3REF: Unlock Notification 6666** 6667** ^When running in shared-cache mode, a database operation may fail with 6668** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 6669** individual tables within the shared-cache cannot be obtained. See 6670** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 6671** ^This API may be used to register a callback that SQLite will invoke 6672** when the connection currently holding the required lock relinquishes it. 6673** ^This API is only available if the library was compiled with the 6674** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 6675** 6676** See Also: [Using the SQLite Unlock Notification Feature]. 6677** 6678** ^Shared-cache locks are released when a database connection concludes 6679** its current transaction, either by committing it or rolling it back. 6680** 6681** ^When a connection (known as the blocked connection) fails to obtain a 6682** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 6683** identity of the database connection (the blocking connection) that 6684** has locked the required resource is stored internally. ^After an 6685** application receives an SQLITE_LOCKED error, it may call the 6686** sqlite3_unlock_notify() method with the blocked connection handle as 6687** the first argument to register for a callback that will be invoked 6688** when the blocking connections current transaction is concluded. ^The 6689** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 6690** call that concludes the blocking connections transaction. 6691** 6692** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 6693** there is a chance that the blocking connection will have already 6694** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 6695** If this happens, then the specified callback is invoked immediately, 6696** from within the call to sqlite3_unlock_notify().)^ 6697** 6698** ^If the blocked connection is attempting to obtain a write-lock on a 6699** shared-cache table, and more than one other connection currently holds 6700** a read-lock on the same table, then SQLite arbitrarily selects one of 6701** the other connections to use as the blocking connection. 6702** 6703** ^(There may be at most one unlock-notify callback registered by a 6704** blocked connection. If sqlite3_unlock_notify() is called when the 6705** blocked connection already has a registered unlock-notify callback, 6706** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 6707** called with a NULL pointer as its second argument, then any existing 6708** unlock-notify callback is canceled. ^The blocked connections 6709** unlock-notify callback may also be canceled by closing the blocked 6710** connection using [sqlite3_close()]. 6711** 6712** The unlock-notify callback is not reentrant. If an application invokes 6713** any sqlite3_xxx API functions from within an unlock-notify callback, a 6714** crash or deadlock may be the result. 6715** 6716** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 6717** returns SQLITE_OK. 6718** 6719** <b>Callback Invocation Details</b> 6720** 6721** When an unlock-notify callback is registered, the application provides a 6722** single void* pointer that is passed to the callback when it is invoked. 6723** However, the signature of the callback function allows SQLite to pass 6724** it an array of void* context pointers. The first argument passed to 6725** an unlock-notify callback is a pointer to an array of void* pointers, 6726** and the second is the number of entries in the array. 6727** 6728** When a blocking connections transaction is concluded, there may be 6729** more than one blocked connection that has registered for an unlock-notify 6730** callback. ^If two or more such blocked connections have specified the 6731** same callback function, then instead of invoking the callback function 6732** multiple times, it is invoked once with the set of void* context pointers 6733** specified by the blocked connections bundled together into an array. 6734** This gives the application an opportunity to prioritize any actions 6735** related to the set of unblocked database connections. 6736** 6737** <b>Deadlock Detection</b> 6738** 6739** Assuming that after registering for an unlock-notify callback a 6740** database waits for the callback to be issued before taking any further 6741** action (a reasonable assumption), then using this API may cause the 6742** application to deadlock. For example, if connection X is waiting for 6743** connection Y's transaction to be concluded, and similarly connection 6744** Y is waiting on connection X's transaction, then neither connection 6745** will proceed and the system may remain deadlocked indefinitely. 6746** 6747** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 6748** detection. ^If a given call to sqlite3_unlock_notify() would put the 6749** system in a deadlocked state, then SQLITE_LOCKED is returned and no 6750** unlock-notify callback is registered. The system is said to be in 6751** a deadlocked state if connection A has registered for an unlock-notify 6752** callback on the conclusion of connection B's transaction, and connection 6753** B has itself registered for an unlock-notify callback when connection 6754** A's transaction is concluded. ^Indirect deadlock is also detected, so 6755** the system is also considered to be deadlocked if connection B has 6756** registered for an unlock-notify callback on the conclusion of connection 6757** C's transaction, where connection C is waiting on connection A. ^Any 6758** number of levels of indirection are allowed. 6759** 6760** <b>The "DROP TABLE" Exception</b> 6761** 6762** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 6763** always appropriate to call sqlite3_unlock_notify(). There is however, 6764** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 6765** SQLite checks if there are any currently executing SELECT statements 6766** that belong to the same connection. If there are, SQLITE_LOCKED is 6767** returned. In this case there is no "blocking connection", so invoking 6768** sqlite3_unlock_notify() results in the unlock-notify callback being 6769** invoked immediately. If the application then re-attempts the "DROP TABLE" 6770** or "DROP INDEX" query, an infinite loop might be the result. 6771** 6772** One way around this problem is to check the extended error code returned 6773** by an sqlite3_step() call. ^(If there is a blocking connection, then the 6774** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 6775** the special "DROP TABLE/INDEX" case, the extended error code is just 6776** SQLITE_LOCKED.)^ 6777*/ 6778int sqlite3_unlock_notify( 6779 sqlite3 *pBlocked, /* Waiting connection */ 6780 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 6781 void *pNotifyArg /* Argument to pass to xNotify */ 6782); 6783 6784 6785/* 6786** CAPI3REF: String Comparison 6787** 6788** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 6789** and extensions to compare the contents of two buffers containing UTF-8 6790** strings in a case-independent fashion, using the same definition of "case 6791** independence" that SQLite uses internally when comparing identifiers. 6792*/ 6793int sqlite3_stricmp(const char *, const char *); 6794int sqlite3_strnicmp(const char *, const char *, int); 6795 6796/* 6797** CAPI3REF: Error Logging Interface 6798** 6799** ^The [sqlite3_log()] interface writes a message into the error log 6800** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 6801** ^If logging is enabled, the zFormat string and subsequent arguments are 6802** used with [sqlite3_snprintf()] to generate the final output string. 6803** 6804** The sqlite3_log() interface is intended for use by extensions such as 6805** virtual tables, collating functions, and SQL functions. While there is 6806** nothing to prevent an application from calling sqlite3_log(), doing so 6807** is considered bad form. 6808** 6809** The zFormat string must not be NULL. 6810** 6811** To avoid deadlocks and other threading problems, the sqlite3_log() routine 6812** will not use dynamically allocated memory. The log message is stored in 6813** a fixed-length buffer on the stack. If the log message is longer than 6814** a few hundred characters, it will be truncated to the length of the 6815** buffer. 6816*/ 6817void sqlite3_log(int iErrCode, const char *zFormat, ...); 6818 6819/* 6820** CAPI3REF: Write-Ahead Log Commit Hook 6821** 6822** ^The [sqlite3_wal_hook()] function is used to register a callback that 6823** will be invoked each time a database connection commits data to a 6824** [write-ahead log] (i.e. whenever a transaction is committed in 6825** [journal_mode | journal_mode=WAL mode]). 6826** 6827** ^The callback is invoked by SQLite after the commit has taken place and 6828** the associated write-lock on the database released, so the implementation 6829** may read, write or [checkpoint] the database as required. 6830** 6831** ^The first parameter passed to the callback function when it is invoked 6832** is a copy of the third parameter passed to sqlite3_wal_hook() when 6833** registering the callback. ^The second is a copy of the database handle. 6834** ^The third parameter is the name of the database that was written to - 6835** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 6836** is the number of pages currently in the write-ahead log file, 6837** including those that were just committed. 6838** 6839** The callback function should normally return [SQLITE_OK]. ^If an error 6840** code is returned, that error will propagate back up through the 6841** SQLite code base to cause the statement that provoked the callback 6842** to report an error, though the commit will have still occurred. If the 6843** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 6844** that does not correspond to any valid SQLite error code, the results 6845** are undefined. 6846** 6847** A single database handle may have at most a single write-ahead log callback 6848** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 6849** previously registered write-ahead log callback. ^Note that the 6850** [sqlite3_wal_autocheckpoint()] interface and the 6851** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 6852** those overwrite any prior [sqlite3_wal_hook()] settings. 6853*/ 6854void *sqlite3_wal_hook( 6855 sqlite3*, 6856 int(*)(void *,sqlite3*,const char*,int), 6857 void* 6858); 6859 6860/* 6861** CAPI3REF: Configure an auto-checkpoint 6862** 6863** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 6864** [sqlite3_wal_hook()] that causes any database on [database connection] D 6865** to automatically [checkpoint] 6866** after committing a transaction if there are N or 6867** more frames in the [write-ahead log] file. ^Passing zero or 6868** a negative value as the nFrame parameter disables automatic 6869** checkpoints entirely. 6870** 6871** ^The callback registered by this function replaces any existing callback 6872** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 6873** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 6874** configured by this function. 6875** 6876** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 6877** from SQL. 6878** 6879** ^Every new [database connection] defaults to having the auto-checkpoint 6880** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 6881** pages. The use of this interface 6882** is only necessary if the default setting is found to be suboptimal 6883** for a particular application. 6884*/ 6885int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 6886 6887/* 6888** CAPI3REF: Checkpoint a database 6889** 6890** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 6891** on [database connection] D to be [checkpointed]. ^If X is NULL or an 6892** empty string, then a checkpoint is run on all databases of 6893** connection D. ^If the database connection D is not in 6894** [WAL | write-ahead log mode] then this interface is a harmless no-op. 6895** 6896** ^The [wal_checkpoint pragma] can be used to invoke this interface 6897** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 6898** [wal_autocheckpoint pragma] can be used to cause this interface to be 6899** run whenever the WAL reaches a certain size threshold. 6900** 6901** See also: [sqlite3_wal_checkpoint_v2()] 6902*/ 6903int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 6904 6905/* 6906** CAPI3REF: Checkpoint a database 6907** 6908** Run a checkpoint operation on WAL database zDb attached to database 6909** handle db. The specific operation is determined by the value of the 6910** eMode parameter: 6911** 6912** <dl> 6913** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 6914** Checkpoint as many frames as possible without waiting for any database 6915** readers or writers to finish. Sync the db file if all frames in the log 6916** are checkpointed. This mode is the same as calling 6917** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked. 6918** 6919** <dt>SQLITE_CHECKPOINT_FULL<dd> 6920** This mode blocks (calls the busy-handler callback) until there is no 6921** database writer and all readers are reading from the most recent database 6922** snapshot. It then checkpoints all frames in the log file and syncs the 6923** database file. This call blocks database writers while it is running, 6924** but not database readers. 6925** 6926** <dt>SQLITE_CHECKPOINT_RESTART<dd> 6927** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after 6928** checkpointing the log file it blocks (calls the busy-handler callback) 6929** until all readers are reading from the database file only. This ensures 6930** that the next client to write to the database file restarts the log file 6931** from the beginning. This call blocks database writers while it is running, 6932** but not database readers. 6933** </dl> 6934** 6935** If pnLog is not NULL, then *pnLog is set to the total number of frames in 6936** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to 6937** the total number of checkpointed frames (including any that were already 6938** checkpointed when this function is called). *pnLog and *pnCkpt may be 6939** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK. 6940** If no values are available because of an error, they are both set to -1 6941** before returning to communicate this to the caller. 6942** 6943** All calls obtain an exclusive "checkpoint" lock on the database file. If 6944** any other process is running a checkpoint operation at the same time, the 6945** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a 6946** busy-handler configured, it will not be invoked in this case. 6947** 6948** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive 6949** "writer" lock on the database file. If the writer lock cannot be obtained 6950** immediately, and a busy-handler is configured, it is invoked and the writer 6951** lock retried until either the busy-handler returns 0 or the lock is 6952** successfully obtained. The busy-handler is also invoked while waiting for 6953** database readers as described above. If the busy-handler returns 0 before 6954** the writer lock is obtained or while waiting for database readers, the 6955** checkpoint operation proceeds from that point in the same way as 6956** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 6957** without blocking any further. SQLITE_BUSY is returned in this case. 6958** 6959** If parameter zDb is NULL or points to a zero length string, then the 6960** specified operation is attempted on all WAL databases. In this case the 6961** values written to output parameters *pnLog and *pnCkpt are undefined. If 6962** an SQLITE_BUSY error is encountered when processing one or more of the 6963** attached WAL databases, the operation is still attempted on any remaining 6964** attached databases and SQLITE_BUSY is returned to the caller. If any other 6965** error occurs while processing an attached database, processing is abandoned 6966** and the error code returned to the caller immediately. If no error 6967** (SQLITE_BUSY or otherwise) is encountered while processing the attached 6968** databases, SQLITE_OK is returned. 6969** 6970** If database zDb is the name of an attached database that is not in WAL 6971** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If 6972** zDb is not NULL (or a zero length string) and is not the name of any 6973** attached database, SQLITE_ERROR is returned to the caller. 6974*/ 6975int sqlite3_wal_checkpoint_v2( 6976 sqlite3 *db, /* Database handle */ 6977 const char *zDb, /* Name of attached database (or NULL) */ 6978 int eMode, /* SQLITE_CHECKPOINT_* value */ 6979 int *pnLog, /* OUT: Size of WAL log in frames */ 6980 int *pnCkpt /* OUT: Total number of frames checkpointed */ 6981); 6982 6983/* 6984** CAPI3REF: Checkpoint operation parameters 6985** 6986** These constants can be used as the 3rd parameter to 6987** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()] 6988** documentation for additional information about the meaning and use of 6989** each of these values. 6990*/ 6991#define SQLITE_CHECKPOINT_PASSIVE 0 6992#define SQLITE_CHECKPOINT_FULL 1 6993#define SQLITE_CHECKPOINT_RESTART 2 6994 6995/* 6996** CAPI3REF: Virtual Table Interface Configuration 6997** 6998** This function may be called by either the [xConnect] or [xCreate] method 6999** of a [virtual table] implementation to configure 7000** various facets of the virtual table interface. 7001** 7002** If this interface is invoked outside the context of an xConnect or 7003** xCreate virtual table method then the behavior is undefined. 7004** 7005** At present, there is only one option that may be configured using 7006** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 7007** may be added in the future. 7008*/ 7009int sqlite3_vtab_config(sqlite3*, int op, ...); 7010 7011/* 7012** CAPI3REF: Virtual Table Configuration Options 7013** 7014** These macros define the various options to the 7015** [sqlite3_vtab_config()] interface that [virtual table] implementations 7016** can use to customize and optimize their behavior. 7017** 7018** <dl> 7019** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 7020** <dd>Calls of the form 7021** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 7022** where X is an integer. If X is zero, then the [virtual table] whose 7023** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 7024** support constraints. In this configuration (which is the default) if 7025** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 7026** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 7027** specified as part of the users SQL statement, regardless of the actual 7028** ON CONFLICT mode specified. 7029** 7030** If X is non-zero, then the virtual table implementation guarantees 7031** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 7032** any modifications to internal or persistent data structures have been made. 7033** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 7034** is able to roll back a statement or database transaction, and abandon 7035** or continue processing the current SQL statement as appropriate. 7036** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 7037** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 7038** had been ABORT. 7039** 7040** Virtual table implementations that are required to handle OR REPLACE 7041** must do so within the [xUpdate] method. If a call to the 7042** [sqlite3_vtab_on_conflict()] function indicates that the current ON 7043** CONFLICT policy is REPLACE, the virtual table implementation should 7044** silently replace the appropriate rows within the xUpdate callback and 7045** return SQLITE_OK. Or, if this is not possible, it may return 7046** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 7047** constraint handling. 7048** </dl> 7049*/ 7050#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 7051 7052/* 7053** CAPI3REF: Determine The Virtual Table Conflict Policy 7054** 7055** This function may only be called from within a call to the [xUpdate] method 7056** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 7057** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 7058** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 7059** of the SQL statement that triggered the call to the [xUpdate] method of the 7060** [virtual table]. 7061*/ 7062int sqlite3_vtab_on_conflict(sqlite3 *); 7063 7064/* 7065** CAPI3REF: Conflict resolution modes 7066** 7067** These constants are returned by [sqlite3_vtab_on_conflict()] to 7068** inform a [virtual table] implementation what the [ON CONFLICT] mode 7069** is for the SQL statement being evaluated. 7070** 7071** Note that the [SQLITE_IGNORE] constant is also used as a potential 7072** return value from the [sqlite3_set_authorizer()] callback and that 7073** [SQLITE_ABORT] is also a [result code]. 7074*/ 7075#define SQLITE_ROLLBACK 1 7076/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 7077#define SQLITE_FAIL 3 7078/* #define SQLITE_ABORT 4 // Also an error code */ 7079#define SQLITE_REPLACE 5 7080 7081 7082 7083/* 7084** Undo the hack that converts floating point types to integer for 7085** builds on processors without floating point support. 7086*/ 7087#ifdef SQLITE_OMIT_FLOATING_POINT 7088# undef double 7089#endif 7090 7091#ifdef __cplusplus 7092} /* End of the 'extern "C"' block */ 7093#endif 7094#endif 7095