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#ifndef SQLITE_API 53# define SQLITE_API 54#endif 55 56 57/* 58** These no-op macros are used in front of interfaces to mark those 59** interfaces as either deprecated or experimental. New applications 60** should not use deprecated interfaces - they are support for backwards 61** compatibility only. Application writers should be aware that 62** experimental interfaces are subject to change in point releases. 63** 64** These macros used to resolve to various kinds of compiler magic that 65** would generate warning messages when they were used. But that 66** compiler magic ended up generating such a flurry of bug reports 67** that we have taken it all out and gone back to using simple 68** noop macros. 69*/ 70#define SQLITE_DEPRECATED 71#define SQLITE_EXPERIMENTAL 72 73/* 74** Ensure these symbols were not defined by some previous header file. 75*/ 76#ifdef SQLITE_VERSION 77# undef SQLITE_VERSION 78#endif 79#ifdef SQLITE_VERSION_NUMBER 80# undef SQLITE_VERSION_NUMBER 81#endif 82 83/* 84** CAPI3REF: Compile-Time Library Version Numbers 85** 86** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 87** evaluates to a string literal that is the SQLite version in the 88** format "X.Y.Z" where X is the major version number (always 3 for 89** SQLite3) and Y is the minor version number and Z is the release number.)^ 90** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 91** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 92** numbers used in [SQLITE_VERSION].)^ 93** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 94** be larger than the release from which it is derived. Either Y will 95** be held constant and Z will be incremented or else Y will be incremented 96** and Z will be reset to zero. 97** 98** Since version 3.6.18, SQLite source code has been stored in the 99** <a href="http://www.fossil-scm.org/">Fossil configuration management 100** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 101** a string which identifies a particular check-in of SQLite 102** within its configuration management system. ^The SQLITE_SOURCE_ID 103** string contains the date and time of the check-in (UTC) and an SHA1 104** hash of the entire source tree. 105** 106** See also: [sqlite3_libversion()], 107** [sqlite3_libversion_number()], [sqlite3_sourceid()], 108** [sqlite_version()] and [sqlite_source_id()]. 109*/ 110#define SQLITE_VERSION "3.7.8" 111#define SQLITE_VERSION_NUMBER 3007008 112#define SQLITE_SOURCE_ID "2011-09-19 14:49:19 3e0da808d2f5b4d12046e05980ca04578f581177" 113 114/* 115** CAPI3REF: Run-Time Library Version Numbers 116** KEYWORDS: sqlite3_version, sqlite3_sourceid 117** 118** These interfaces provide the same information as the [SQLITE_VERSION], 119** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 120** but are associated with the library instead of the header file. ^(Cautious 121** programmers might include assert() statements in their application to 122** verify that values returned by these interfaces match the macros in 123** the header, and thus insure that the application is 124** compiled with matching library and header files. 125** 126** <blockquote><pre> 127** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 128** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 129** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 130** </pre></blockquote>)^ 131** 132** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 133** macro. ^The sqlite3_libversion() function returns a pointer to the 134** to the sqlite3_version[] string constant. The sqlite3_libversion() 135** function is provided for use in DLLs since DLL users usually do not have 136** direct access to string constants within the DLL. ^The 137** sqlite3_libversion_number() function returns an integer equal to 138** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 139** a pointer to a string constant whose value is the same as the 140** [SQLITE_SOURCE_ID] C preprocessor macro. 141** 142** See also: [sqlite_version()] and [sqlite_source_id()]. 143*/ 144SQLITE_API SQLITE_EXTERN const char sqlite3_version[]; 145SQLITE_API const char *sqlite3_libversion(void); 146SQLITE_API const char *sqlite3_sourceid(void); 147SQLITE_API int sqlite3_libversion_number(void); 148 149/* 150** CAPI3REF: Run-Time Library Compilation Options Diagnostics 151** 152** ^The sqlite3_compileoption_used() function returns 0 or 1 153** indicating whether the specified option was defined at 154** compile time. ^The SQLITE_ prefix may be omitted from the 155** option name passed to sqlite3_compileoption_used(). 156** 157** ^The sqlite3_compileoption_get() function allows iterating 158** over the list of options that were defined at compile time by 159** returning the N-th compile time option string. ^If N is out of range, 160** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 161** prefix is omitted from any strings returned by 162** sqlite3_compileoption_get(). 163** 164** ^Support for the diagnostic functions sqlite3_compileoption_used() 165** and sqlite3_compileoption_get() may be omitted by specifying the 166** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 167** 168** See also: SQL functions [sqlite_compileoption_used()] and 169** [sqlite_compileoption_get()] and the [compile_options pragma]. 170*/ 171#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 172SQLITE_API int sqlite3_compileoption_used(const char *zOptName); 173SQLITE_API const char *sqlite3_compileoption_get(int N); 174#endif 175 176/* 177** CAPI3REF: Test To See If The Library Is Threadsafe 178** 179** ^The sqlite3_threadsafe() function returns zero if and only if 180** SQLite was compiled mutexing code omitted due to the 181** [SQLITE_THREADSAFE] compile-time option being set to 0. 182** 183** SQLite can be compiled with or without mutexes. When 184** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 185** are enabled and SQLite is threadsafe. When the 186** [SQLITE_THREADSAFE] macro is 0, 187** the mutexes are omitted. Without the mutexes, it is not safe 188** to use SQLite concurrently from more than one thread. 189** 190** Enabling mutexes incurs a measurable performance penalty. 191** So if speed is of utmost importance, it makes sense to disable 192** the mutexes. But for maximum safety, mutexes should be enabled. 193** ^The default behavior is for mutexes to be enabled. 194** 195** This interface can be used by an application to make sure that the 196** version of SQLite that it is linking against was compiled with 197** the desired setting of the [SQLITE_THREADSAFE] macro. 198** 199** This interface only reports on the compile-time mutex setting 200** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 201** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 202** can be fully or partially disabled using a call to [sqlite3_config()] 203** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 204** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the 205** sqlite3_threadsafe() function shows only the compile-time setting of 206** thread safety, not any run-time changes to that setting made by 207** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 208** is unchanged by calls to sqlite3_config().)^ 209** 210** See the [threading mode] documentation for additional information. 211*/ 212SQLITE_API int sqlite3_threadsafe(void); 213 214/* 215** CAPI3REF: Database Connection Handle 216** KEYWORDS: {database connection} {database connections} 217** 218** Each open SQLite database is represented by a pointer to an instance of 219** the opaque structure named "sqlite3". It is useful to think of an sqlite3 220** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 221** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 222** is its destructor. There are many other interfaces (such as 223** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 224** [sqlite3_busy_timeout()] to name but three) that are methods on an 225** sqlite3 object. 226*/ 227typedef struct sqlite3 sqlite3; 228 229/* 230** CAPI3REF: 64-Bit Integer Types 231** KEYWORDS: sqlite_int64 sqlite_uint64 232** 233** Because there is no cross-platform way to specify 64-bit integer types 234** SQLite includes typedefs for 64-bit signed and unsigned integers. 235** 236** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 237** The sqlite_int64 and sqlite_uint64 types are supported for backwards 238** compatibility only. 239** 240** ^The sqlite3_int64 and sqlite_int64 types can store integer values 241** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 242** sqlite3_uint64 and sqlite_uint64 types can store integer values 243** between 0 and +18446744073709551615 inclusive. 244*/ 245#ifdef SQLITE_INT64_TYPE 246 typedef SQLITE_INT64_TYPE sqlite_int64; 247 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 248#elif defined(_MSC_VER) || defined(__BORLANDC__) 249 typedef __int64 sqlite_int64; 250 typedef unsigned __int64 sqlite_uint64; 251#else 252 typedef long long int sqlite_int64; 253 typedef unsigned long long int sqlite_uint64; 254#endif 255typedef sqlite_int64 sqlite3_int64; 256typedef sqlite_uint64 sqlite3_uint64; 257 258/* 259** If compiling for a processor that lacks floating point support, 260** substitute integer for floating-point. 261*/ 262#ifdef SQLITE_OMIT_FLOATING_POINT 263# define double sqlite3_int64 264#endif 265 266/* 267** CAPI3REF: Closing A Database Connection 268** 269** ^The sqlite3_close() routine is the destructor for the [sqlite3] object. 270** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is 271** successfully destroyed and all associated resources are deallocated. 272** 273** Applications must [sqlite3_finalize | finalize] all [prepared statements] 274** and [sqlite3_blob_close | close] all [BLOB handles] associated with 275** the [sqlite3] object prior to attempting to close the object. ^If 276** sqlite3_close() is called on a [database connection] that still has 277** outstanding [prepared statements] or [BLOB handles], then it returns 278** SQLITE_BUSY. 279** 280** ^If [sqlite3_close()] is invoked while a transaction is open, 281** the transaction is automatically rolled back. 282** 283** The C parameter to [sqlite3_close(C)] must be either a NULL 284** pointer or an [sqlite3] object pointer obtained 285** from [sqlite3_open()], [sqlite3_open16()], or 286** [sqlite3_open_v2()], and not previously closed. 287** ^Calling sqlite3_close() with a NULL pointer argument is a 288** harmless no-op. 289*/ 290SQLITE_API int sqlite3_close(sqlite3 *); 291 292/* 293** The type for a callback function. 294** This is legacy and deprecated. It is included for historical 295** compatibility and is not documented. 296*/ 297typedef int (*sqlite3_callback)(void*,int,char**, char**); 298 299/* 300** CAPI3REF: One-Step Query Execution Interface 301** 302** The sqlite3_exec() interface is a convenience wrapper around 303** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 304** that allows an application to run multiple statements of SQL 305** without having to use a lot of C code. 306** 307** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 308** semicolon-separate SQL statements passed into its 2nd argument, 309** in the context of the [database connection] passed in as its 1st 310** argument. ^If the callback function of the 3rd argument to 311** sqlite3_exec() is not NULL, then it is invoked for each result row 312** coming out of the evaluated SQL statements. ^The 4th argument to 313** sqlite3_exec() is relayed through to the 1st argument of each 314** callback invocation. ^If the callback pointer to sqlite3_exec() 315** is NULL, then no callback is ever invoked and result rows are 316** ignored. 317** 318** ^If an error occurs while evaluating the SQL statements passed into 319** sqlite3_exec(), then execution of the current statement stops and 320** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 321** is not NULL then any error message is written into memory obtained 322** from [sqlite3_malloc()] and passed back through the 5th parameter. 323** To avoid memory leaks, the application should invoke [sqlite3_free()] 324** on error message strings returned through the 5th parameter of 325** of sqlite3_exec() after the error message string is no longer needed. 326** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 327** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 328** NULL before returning. 329** 330** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 331** routine returns SQLITE_ABORT without invoking the callback again and 332** without running any subsequent SQL statements. 333** 334** ^The 2nd argument to the sqlite3_exec() callback function is the 335** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 336** callback is an array of pointers to strings obtained as if from 337** [sqlite3_column_text()], one for each column. ^If an element of a 338** result row is NULL then the corresponding string pointer for the 339** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 340** sqlite3_exec() callback is an array of pointers to strings where each 341** entry represents the name of corresponding result column as obtained 342** from [sqlite3_column_name()]. 343** 344** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 345** to an empty string, or a pointer that contains only whitespace and/or 346** SQL comments, then no SQL statements are evaluated and the database 347** is not changed. 348** 349** Restrictions: 350** 351** <ul> 352** <li> The application must insure that the 1st parameter to sqlite3_exec() 353** is a valid and open [database connection]. 354** <li> The application must not close [database connection] specified by 355** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 356** <li> The application must not modify the SQL statement text passed into 357** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 358** </ul> 359*/ 360SQLITE_API int sqlite3_exec( 361 sqlite3*, /* An open database */ 362 const char *sql, /* SQL to be evaluated */ 363 int (*callback)(void*,int,char**,char**), /* Callback function */ 364 void *, /* 1st argument to callback */ 365 char **errmsg /* Error msg written here */ 366); 367 368/* 369** CAPI3REF: Result Codes 370** KEYWORDS: SQLITE_OK {error code} {error codes} 371** KEYWORDS: {result code} {result codes} 372** 373** Many SQLite functions return an integer result code from the set shown 374** here in order to indicates success or failure. 375** 376** New error codes may be added in future versions of SQLite. 377** 378** See also: [SQLITE_IOERR_READ | extended result codes], 379** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes]. 380*/ 381#define SQLITE_OK 0 /* Successful result */ 382/* beginning-of-error-codes */ 383#define SQLITE_ERROR 1 /* SQL error or missing database */ 384#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 385#define SQLITE_PERM 3 /* Access permission denied */ 386#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 387#define SQLITE_BUSY 5 /* The database file is locked */ 388#define SQLITE_LOCKED 6 /* A table in the database is locked */ 389#define SQLITE_NOMEM 7 /* A malloc() failed */ 390#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 391#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 392#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 393#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 394#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 395#define SQLITE_FULL 13 /* Insertion failed because database is full */ 396#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 397#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 398#define SQLITE_EMPTY 16 /* Database is empty */ 399#define SQLITE_SCHEMA 17 /* The database schema changed */ 400#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 401#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 402#define SQLITE_MISMATCH 20 /* Data type mismatch */ 403#define SQLITE_MISUSE 21 /* Library used incorrectly */ 404#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 405#define SQLITE_AUTH 23 /* Authorization denied */ 406#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 407#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 408#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 409#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 410#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 411/* end-of-error-codes */ 412 413/* 414** CAPI3REF: Extended Result Codes 415** KEYWORDS: {extended error code} {extended error codes} 416** KEYWORDS: {extended result code} {extended result codes} 417** 418** In its default configuration, SQLite API routines return one of 26 integer 419** [SQLITE_OK | result codes]. However, experience has shown that many of 420** these result codes are too coarse-grained. They do not provide as 421** much information about problems as programmers might like. In an effort to 422** address this, newer versions of SQLite (version 3.3.8 and later) include 423** support for additional result codes that provide more detailed information 424** about errors. The extended result codes are enabled or disabled 425** on a per database connection basis using the 426** [sqlite3_extended_result_codes()] API. 427** 428** Some of the available extended result codes are listed here. 429** One may expect the number of extended result codes will be expand 430** over time. Software that uses extended result codes should expect 431** to see new result codes in future releases of SQLite. 432** 433** The SQLITE_OK result code will never be extended. It will always 434** be exactly zero. 435*/ 436#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 437#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 438#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 439#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 440#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 441#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 442#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 443#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 444#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 445#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 446#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 447#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 448#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 449#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 450#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 451#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 452#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 453#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 454#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 455#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 456#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 457#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 458#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 459#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 460#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 461#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 462#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 463#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 464 465/* 466** CAPI3REF: Flags For File Open Operations 467** 468** These bit values are intended for use in the 469** 3rd parameter to the [sqlite3_open_v2()] interface and 470** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 471*/ 472#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 473#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 474#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 475#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 476#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 477#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 478#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 479#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 480#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 481#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 482#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 483#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 484#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 485#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 486#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 487#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 488#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 489#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 490#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 491 492/* Reserved: 0x00F00000 */ 493 494/* 495** CAPI3REF: Device Characteristics 496** 497** The xDeviceCharacteristics method of the [sqlite3_io_methods] 498** object returns an integer which is a vector of the these 499** bit values expressing I/O characteristics of the mass storage 500** device that holds the file that the [sqlite3_io_methods] 501** refers to. 502** 503** The SQLITE_IOCAP_ATOMIC property means that all writes of 504** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 505** mean that writes of blocks that are nnn bytes in size and 506** are aligned to an address which is an integer multiple of 507** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 508** that when data is appended to a file, the data is appended 509** first then the size of the file is extended, never the other 510** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 511** information is written to disk in the same order as calls 512** to xWrite(). 513*/ 514#define SQLITE_IOCAP_ATOMIC 0x00000001 515#define SQLITE_IOCAP_ATOMIC512 0x00000002 516#define SQLITE_IOCAP_ATOMIC1K 0x00000004 517#define SQLITE_IOCAP_ATOMIC2K 0x00000008 518#define SQLITE_IOCAP_ATOMIC4K 0x00000010 519#define SQLITE_IOCAP_ATOMIC8K 0x00000020 520#define SQLITE_IOCAP_ATOMIC16K 0x00000040 521#define SQLITE_IOCAP_ATOMIC32K 0x00000080 522#define SQLITE_IOCAP_ATOMIC64K 0x00000100 523#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 524#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 525#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 526 527/* 528** CAPI3REF: File Locking Levels 529** 530** SQLite uses one of these integer values as the second 531** argument to calls it makes to the xLock() and xUnlock() methods 532** of an [sqlite3_io_methods] object. 533*/ 534#define SQLITE_LOCK_NONE 0 535#define SQLITE_LOCK_SHARED 1 536#define SQLITE_LOCK_RESERVED 2 537#define SQLITE_LOCK_PENDING 3 538#define SQLITE_LOCK_EXCLUSIVE 4 539 540/* 541** CAPI3REF: Synchronization Type Flags 542** 543** When SQLite invokes the xSync() method of an 544** [sqlite3_io_methods] object it uses a combination of 545** these integer values as the second argument. 546** 547** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 548** sync operation only needs to flush data to mass storage. Inode 549** information need not be flushed. If the lower four bits of the flag 550** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 551** If the lower four bits equal SQLITE_SYNC_FULL, that means 552** to use Mac OS X style fullsync instead of fsync(). 553** 554** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 555** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 556** settings. The [synchronous pragma] determines when calls to the 557** xSync VFS method occur and applies uniformly across all platforms. 558** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 559** energetic or rigorous or forceful the sync operations are and 560** only make a difference on Mac OSX for the default SQLite code. 561** (Third-party VFS implementations might also make the distinction 562** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 563** operating systems natively supported by SQLite, only Mac OSX 564** cares about the difference.) 565*/ 566#define SQLITE_SYNC_NORMAL 0x00002 567#define SQLITE_SYNC_FULL 0x00003 568#define SQLITE_SYNC_DATAONLY 0x00010 569 570/* 571** CAPI3REF: OS Interface Open File Handle 572** 573** An [sqlite3_file] object represents an open file in the 574** [sqlite3_vfs | OS interface layer]. Individual OS interface 575** implementations will 576** want to subclass this object by appending additional fields 577** for their own use. The pMethods entry is a pointer to an 578** [sqlite3_io_methods] object that defines methods for performing 579** I/O operations on the open file. 580*/ 581typedef struct sqlite3_file sqlite3_file; 582struct sqlite3_file { 583 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 584}; 585 586/* 587** CAPI3REF: OS Interface File Virtual Methods Object 588** 589** Every file opened by the [sqlite3_vfs.xOpen] method populates an 590** [sqlite3_file] object (or, more commonly, a subclass of the 591** [sqlite3_file] object) with a pointer to an instance of this object. 592** This object defines the methods used to perform various operations 593** against the open file represented by the [sqlite3_file] object. 594** 595** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 596** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 597** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 598** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 599** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 600** to NULL. 601** 602** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 603** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 604** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 605** flag may be ORed in to indicate that only the data of the file 606** and not its inode needs to be synced. 607** 608** The integer values to xLock() and xUnlock() are one of 609** <ul> 610** <li> [SQLITE_LOCK_NONE], 611** <li> [SQLITE_LOCK_SHARED], 612** <li> [SQLITE_LOCK_RESERVED], 613** <li> [SQLITE_LOCK_PENDING], or 614** <li> [SQLITE_LOCK_EXCLUSIVE]. 615** </ul> 616** xLock() increases the lock. xUnlock() decreases the lock. 617** The xCheckReservedLock() method checks whether any database connection, 618** either in this process or in some other process, is holding a RESERVED, 619** PENDING, or EXCLUSIVE lock on the file. It returns true 620** if such a lock exists and false otherwise. 621** 622** The xFileControl() method is a generic interface that allows custom 623** VFS implementations to directly control an open file using the 624** [sqlite3_file_control()] interface. The second "op" argument is an 625** integer opcode. The third argument is a generic pointer intended to 626** point to a structure that may contain arguments or space in which to 627** write return values. Potential uses for xFileControl() might be 628** functions to enable blocking locks with timeouts, to change the 629** locking strategy (for example to use dot-file locks), to inquire 630** about the status of a lock, or to break stale locks. The SQLite 631** core reserves all opcodes less than 100 for its own use. 632** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 633** Applications that define a custom xFileControl method should use opcodes 634** greater than 100 to avoid conflicts. VFS implementations should 635** return [SQLITE_NOTFOUND] for file control opcodes that they do not 636** recognize. 637** 638** The xSectorSize() method returns the sector size of the 639** device that underlies the file. The sector size is the 640** minimum write that can be performed without disturbing 641** other bytes in the file. The xDeviceCharacteristics() 642** method returns a bit vector describing behaviors of the 643** underlying device: 644** 645** <ul> 646** <li> [SQLITE_IOCAP_ATOMIC] 647** <li> [SQLITE_IOCAP_ATOMIC512] 648** <li> [SQLITE_IOCAP_ATOMIC1K] 649** <li> [SQLITE_IOCAP_ATOMIC2K] 650** <li> [SQLITE_IOCAP_ATOMIC4K] 651** <li> [SQLITE_IOCAP_ATOMIC8K] 652** <li> [SQLITE_IOCAP_ATOMIC16K] 653** <li> [SQLITE_IOCAP_ATOMIC32K] 654** <li> [SQLITE_IOCAP_ATOMIC64K] 655** <li> [SQLITE_IOCAP_SAFE_APPEND] 656** <li> [SQLITE_IOCAP_SEQUENTIAL] 657** </ul> 658** 659** The SQLITE_IOCAP_ATOMIC property means that all writes of 660** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 661** mean that writes of blocks that are nnn bytes in size and 662** are aligned to an address which is an integer multiple of 663** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 664** that when data is appended to a file, the data is appended 665** first then the size of the file is extended, never the other 666** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 667** information is written to disk in the same order as calls 668** to xWrite(). 669** 670** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 671** in the unread portions of the buffer with zeros. A VFS that 672** fails to zero-fill short reads might seem to work. However, 673** failure to zero-fill short reads will eventually lead to 674** database corruption. 675*/ 676typedef struct sqlite3_io_methods sqlite3_io_methods; 677struct sqlite3_io_methods { 678 int iVersion; 679 int (*xClose)(sqlite3_file*); 680 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 681 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 682 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 683 int (*xSync)(sqlite3_file*, int flags); 684 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 685 int (*xLock)(sqlite3_file*, int); 686 int (*xUnlock)(sqlite3_file*, int); 687 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 688 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 689 int (*xSectorSize)(sqlite3_file*); 690 int (*xDeviceCharacteristics)(sqlite3_file*); 691 /* Methods above are valid for version 1 */ 692 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 693 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 694 void (*xShmBarrier)(sqlite3_file*); 695 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 696 /* Methods above are valid for version 2 */ 697 /* Additional methods may be added in future releases */ 698}; 699 700/* 701** CAPI3REF: Standard File Control Opcodes 702** 703** These integer constants are opcodes for the xFileControl method 704** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 705** interface. 706** 707** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 708** opcode causes the xFileControl method to write the current state of 709** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 710** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 711** into an integer that the pArg argument points to. This capability 712** is used during testing and only needs to be supported when SQLITE_TEST 713** is defined. 714** 715** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 716** layer a hint of how large the database file will grow to be during the 717** current transaction. This hint is not guaranteed to be accurate but it 718** is often close. The underlying VFS might choose to preallocate database 719** file space based on this hint in order to help writes to the database 720** file run faster. 721** 722** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 723** extends and truncates the database file in chunks of a size specified 724** by the user. The fourth argument to [sqlite3_file_control()] should 725** point to an integer (type int) containing the new chunk-size to use 726** for the nominated database. Allocating database file space in large 727** chunks (say 1MB at a time), may reduce file-system fragmentation and 728** improve performance on some systems. 729** 730** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 731** to the [sqlite3_file] object associated with a particular database 732** connection. See the [sqlite3_file_control()] documentation for 733** additional information. 734** 735** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by 736** SQLite and sent to all VFSes in place of a call to the xSync method 737** when the database connection has [PRAGMA synchronous] set to OFF.)^ 738** Some specialized VFSes need this signal in order to operate correctly 739** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most 740** VFSes do not need this signal and should silently ignore this opcode. 741** Applications should not call [sqlite3_file_control()] with this 742** opcode as doing so may disrupt the operation of the specialized VFSes 743** that do require it. 744** 745** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 746** retry counts and intervals for certain disk I/O operations for the 747** windows [VFS] in order to work to provide robustness against 748** anti-virus programs. By default, the windows VFS will retry file read, 749** file write, and file delete opertions up to 10 times, with a delay 750** of 25 milliseconds before the first retry and with the delay increasing 751** by an additional 25 milliseconds with each subsequent retry. This 752** opcode allows those to values (10 retries and 25 milliseconds of delay) 753** to be adjusted. The values are changed for all database connections 754** within the same process. The argument is a pointer to an array of two 755** integers where the first integer i the new retry count and the second 756** integer is the delay. If either integer is negative, then the setting 757** is not changed but instead the prior value of that setting is written 758** into the array entry, allowing the current retry settings to be 759** interrogated. The zDbName parameter is ignored. 760** 761** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 762** persistent [WAL | Write AHead Log] setting. By default, the auxiliary 763** write ahead log and shared memory files used for transaction control 764** are automatically deleted when the latest connection to the database 765** closes. Setting persistent WAL mode causes those files to persist after 766** close. Persisting the files is useful when other processes that do not 767** have write permission on the directory containing the database file want 768** to read the database file, as the WAL and shared memory files must exist 769** in order for the database to be readable. The fourth parameter to 770** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 771** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 772** WAL mode. If the integer is -1, then it is overwritten with the current 773** WAL persistence setting. 774** 775*/ 776#define SQLITE_FCNTL_LOCKSTATE 1 777#define SQLITE_GET_LOCKPROXYFILE 2 778#define SQLITE_SET_LOCKPROXYFILE 3 779#define SQLITE_LAST_ERRNO 4 780#define SQLITE_FCNTL_SIZE_HINT 5 781#define SQLITE_FCNTL_CHUNK_SIZE 6 782#define SQLITE_FCNTL_FILE_POINTER 7 783#define SQLITE_FCNTL_SYNC_OMITTED 8 784#define SQLITE_FCNTL_WIN32_AV_RETRY 9 785#define SQLITE_FCNTL_PERSIST_WAL 10 786 787/* 788** CAPI3REF: Mutex Handle 789** 790** The mutex module within SQLite defines [sqlite3_mutex] to be an 791** abstract type for a mutex object. The SQLite core never looks 792** at the internal representation of an [sqlite3_mutex]. It only 793** deals with pointers to the [sqlite3_mutex] object. 794** 795** Mutexes are created using [sqlite3_mutex_alloc()]. 796*/ 797typedef struct sqlite3_mutex sqlite3_mutex; 798 799/* 800** CAPI3REF: OS Interface Object 801** 802** An instance of the sqlite3_vfs object defines the interface between 803** the SQLite core and the underlying operating system. The "vfs" 804** in the name of the object stands for "virtual file system". See 805** the [VFS | VFS documentation] for further information. 806** 807** The value of the iVersion field is initially 1 but may be larger in 808** future versions of SQLite. Additional fields may be appended to this 809** object when the iVersion value is increased. Note that the structure 810** of the sqlite3_vfs object changes in the transaction between 811** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 812** modified. 813** 814** The szOsFile field is the size of the subclassed [sqlite3_file] 815** structure used by this VFS. mxPathname is the maximum length of 816** a pathname in this VFS. 817** 818** Registered sqlite3_vfs objects are kept on a linked list formed by 819** the pNext pointer. The [sqlite3_vfs_register()] 820** and [sqlite3_vfs_unregister()] interfaces manage this list 821** in a thread-safe way. The [sqlite3_vfs_find()] interface 822** searches the list. Neither the application code nor the VFS 823** implementation should use the pNext pointer. 824** 825** The pNext field is the only field in the sqlite3_vfs 826** structure that SQLite will ever modify. SQLite will only access 827** or modify this field while holding a particular static mutex. 828** The application should never modify anything within the sqlite3_vfs 829** object once the object has been registered. 830** 831** The zName field holds the name of the VFS module. The name must 832** be unique across all VFS modules. 833** 834** [[sqlite3_vfs.xOpen]] 835** ^SQLite guarantees that the zFilename parameter to xOpen 836** is either a NULL pointer or string obtained 837** from xFullPathname() with an optional suffix added. 838** ^If a suffix is added to the zFilename parameter, it will 839** consist of a single "-" character followed by no more than 840** 10 alphanumeric and/or "-" characters. 841** ^SQLite further guarantees that 842** the string will be valid and unchanged until xClose() is 843** called. Because of the previous sentence, 844** the [sqlite3_file] can safely store a pointer to the 845** filename if it needs to remember the filename for some reason. 846** If the zFilename parameter to xOpen is a NULL pointer then xOpen 847** must invent its own temporary name for the file. ^Whenever the 848** xFilename parameter is NULL it will also be the case that the 849** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 850** 851** The flags argument to xOpen() includes all bits set in 852** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 853** or [sqlite3_open16()] is used, then flags includes at least 854** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 855** If xOpen() opens a file read-only then it sets *pOutFlags to 856** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 857** 858** ^(SQLite will also add one of the following flags to the xOpen() 859** call, depending on the object being opened: 860** 861** <ul> 862** <li> [SQLITE_OPEN_MAIN_DB] 863** <li> [SQLITE_OPEN_MAIN_JOURNAL] 864** <li> [SQLITE_OPEN_TEMP_DB] 865** <li> [SQLITE_OPEN_TEMP_JOURNAL] 866** <li> [SQLITE_OPEN_TRANSIENT_DB] 867** <li> [SQLITE_OPEN_SUBJOURNAL] 868** <li> [SQLITE_OPEN_MASTER_JOURNAL] 869** <li> [SQLITE_OPEN_WAL] 870** </ul>)^ 871** 872** The file I/O implementation can use the object type flags to 873** change the way it deals with files. For example, an application 874** that does not care about crash recovery or rollback might make 875** the open of a journal file a no-op. Writes to this journal would 876** also be no-ops, and any attempt to read the journal would return 877** SQLITE_IOERR. Or the implementation might recognize that a database 878** file will be doing page-aligned sector reads and writes in a random 879** order and set up its I/O subsystem accordingly. 880** 881** SQLite might also add one of the following flags to the xOpen method: 882** 883** <ul> 884** <li> [SQLITE_OPEN_DELETEONCLOSE] 885** <li> [SQLITE_OPEN_EXCLUSIVE] 886** </ul> 887** 888** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 889** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 890** will be set for TEMP databases and their journals, transient 891** databases, and subjournals. 892** 893** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 894** with the [SQLITE_OPEN_CREATE] flag, which are both directly 895** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 896** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 897** SQLITE_OPEN_CREATE, is used to indicate that file should always 898** be created, and that it is an error if it already exists. 899** It is <i>not</i> used to indicate the file should be opened 900** for exclusive access. 901** 902** ^At least szOsFile bytes of memory are allocated by SQLite 903** to hold the [sqlite3_file] structure passed as the third 904** argument to xOpen. The xOpen method does not have to 905** allocate the structure; it should just fill it in. Note that 906** the xOpen method must set the sqlite3_file.pMethods to either 907** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 908** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 909** element will be valid after xOpen returns regardless of the success 910** or failure of the xOpen call. 911** 912** [[sqlite3_vfs.xAccess]] 913** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 914** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 915** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 916** to test whether a file is at least readable. The file can be a 917** directory. 918** 919** ^SQLite will always allocate at least mxPathname+1 bytes for the 920** output buffer xFullPathname. The exact size of the output buffer 921** is also passed as a parameter to both methods. If the output buffer 922** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 923** handled as a fatal error by SQLite, vfs implementations should endeavor 924** to prevent this by setting mxPathname to a sufficiently large value. 925** 926** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 927** interfaces are not strictly a part of the filesystem, but they are 928** included in the VFS structure for completeness. 929** The xRandomness() function attempts to return nBytes bytes 930** of good-quality randomness into zOut. The return value is 931** the actual number of bytes of randomness obtained. 932** The xSleep() method causes the calling thread to sleep for at 933** least the number of microseconds given. ^The xCurrentTime() 934** method returns a Julian Day Number for the current date and time as 935** a floating point value. 936** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 937** Day Number multiplied by 86400000 (the number of milliseconds in 938** a 24-hour day). 939** ^SQLite will use the xCurrentTimeInt64() method to get the current 940** date and time if that method is available (if iVersion is 2 or 941** greater and the function pointer is not NULL) and will fall back 942** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 943** 944** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 945** are not used by the SQLite core. These optional interfaces are provided 946** by some VFSes to facilitate testing of the VFS code. By overriding 947** system calls with functions under its control, a test program can 948** simulate faults and error conditions that would otherwise be difficult 949** or impossible to induce. The set of system calls that can be overridden 950** varies from one VFS to another, and from one version of the same VFS to the 951** next. Applications that use these interfaces must be prepared for any 952** or all of these interfaces to be NULL or for their behavior to change 953** from one release to the next. Applications must not attempt to access 954** any of these methods if the iVersion of the VFS is less than 3. 955*/ 956typedef struct sqlite3_vfs sqlite3_vfs; 957typedef void (*sqlite3_syscall_ptr)(void); 958struct sqlite3_vfs { 959 int iVersion; /* Structure version number (currently 3) */ 960 int szOsFile; /* Size of subclassed sqlite3_file */ 961 int mxPathname; /* Maximum file pathname length */ 962 sqlite3_vfs *pNext; /* Next registered VFS */ 963 const char *zName; /* Name of this virtual file system */ 964 void *pAppData; /* Pointer to application-specific data */ 965 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 966 int flags, int *pOutFlags); 967 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 968 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 969 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 970 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 971 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 972 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 973 void (*xDlClose)(sqlite3_vfs*, void*); 974 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 975 int (*xSleep)(sqlite3_vfs*, int microseconds); 976 int (*xCurrentTime)(sqlite3_vfs*, double*); 977 int (*xGetLastError)(sqlite3_vfs*, int, char *); 978 /* 979 ** The methods above are in version 1 of the sqlite_vfs object 980 ** definition. Those that follow are added in version 2 or later 981 */ 982 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 983 /* 984 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 985 ** Those below are for version 3 and greater. 986 */ 987 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 988 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 989 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 990 /* 991 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 992 ** New fields may be appended in figure versions. The iVersion 993 ** value will increment whenever this happens. 994 */ 995}; 996 997/* 998** CAPI3REF: Flags for the xAccess VFS method 999** 1000** These integer constants can be used as the third parameter to 1001** the xAccess method of an [sqlite3_vfs] object. They determine 1002** what kind of permissions the xAccess method is looking for. 1003** With SQLITE_ACCESS_EXISTS, the xAccess method 1004** simply checks whether the file exists. 1005** With SQLITE_ACCESS_READWRITE, the xAccess method 1006** checks whether the named directory is both readable and writable 1007** (in other words, if files can be added, removed, and renamed within 1008** the directory). 1009** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1010** [temp_store_directory pragma], though this could change in a future 1011** release of SQLite. 1012** With SQLITE_ACCESS_READ, the xAccess method 1013** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1014** currently unused, though it might be used in a future release of 1015** SQLite. 1016*/ 1017#define SQLITE_ACCESS_EXISTS 0 1018#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1019#define SQLITE_ACCESS_READ 2 /* Unused */ 1020 1021/* 1022** CAPI3REF: Flags for the xShmLock VFS method 1023** 1024** These integer constants define the various locking operations 1025** allowed by the xShmLock method of [sqlite3_io_methods]. The 1026** following are the only legal combinations of flags to the 1027** xShmLock method: 1028** 1029** <ul> 1030** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1031** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1032** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1033** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1034** </ul> 1035** 1036** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1037** was given no the corresponding lock. 1038** 1039** The xShmLock method can transition between unlocked and SHARED or 1040** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1041** and EXCLUSIVE. 1042*/ 1043#define SQLITE_SHM_UNLOCK 1 1044#define SQLITE_SHM_LOCK 2 1045#define SQLITE_SHM_SHARED 4 1046#define SQLITE_SHM_EXCLUSIVE 8 1047 1048/* 1049** CAPI3REF: Maximum xShmLock index 1050** 1051** The xShmLock method on [sqlite3_io_methods] may use values 1052** between 0 and this upper bound as its "offset" argument. 1053** The SQLite core will never attempt to acquire or release a 1054** lock outside of this range 1055*/ 1056#define SQLITE_SHM_NLOCK 8 1057 1058 1059/* 1060** CAPI3REF: Initialize The SQLite Library 1061** 1062** ^The sqlite3_initialize() routine initializes the 1063** SQLite library. ^The sqlite3_shutdown() routine 1064** deallocates any resources that were allocated by sqlite3_initialize(). 1065** These routines are designed to aid in process initialization and 1066** shutdown on embedded systems. Workstation applications using 1067** SQLite normally do not need to invoke either of these routines. 1068** 1069** A call to sqlite3_initialize() is an "effective" call if it is 1070** the first time sqlite3_initialize() is invoked during the lifetime of 1071** the process, or if it is the first time sqlite3_initialize() is invoked 1072** following a call to sqlite3_shutdown(). ^(Only an effective call 1073** of sqlite3_initialize() does any initialization. All other calls 1074** are harmless no-ops.)^ 1075** 1076** A call to sqlite3_shutdown() is an "effective" call if it is the first 1077** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1078** an effective call to sqlite3_shutdown() does any deinitialization. 1079** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1080** 1081** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1082** is not. The sqlite3_shutdown() interface must only be called from a 1083** single thread. All open [database connections] must be closed and all 1084** other SQLite resources must be deallocated prior to invoking 1085** sqlite3_shutdown(). 1086** 1087** Among other things, ^sqlite3_initialize() will invoke 1088** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1089** will invoke sqlite3_os_end(). 1090** 1091** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1092** ^If for some reason, sqlite3_initialize() is unable to initialize 1093** the library (perhaps it is unable to allocate a needed resource such 1094** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1095** 1096** ^The sqlite3_initialize() routine is called internally by many other 1097** SQLite interfaces so that an application usually does not need to 1098** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1099** calls sqlite3_initialize() so the SQLite library will be automatically 1100** initialized when [sqlite3_open()] is called if it has not be initialized 1101** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1102** compile-time option, then the automatic calls to sqlite3_initialize() 1103** are omitted and the application must call sqlite3_initialize() directly 1104** prior to using any other SQLite interface. For maximum portability, 1105** it is recommended that applications always invoke sqlite3_initialize() 1106** directly prior to using any other SQLite interface. Future releases 1107** of SQLite may require this. In other words, the behavior exhibited 1108** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1109** default behavior in some future release of SQLite. 1110** 1111** The sqlite3_os_init() routine does operating-system specific 1112** initialization of the SQLite library. The sqlite3_os_end() 1113** routine undoes the effect of sqlite3_os_init(). Typical tasks 1114** performed by these routines include allocation or deallocation 1115** of static resources, initialization of global variables, 1116** setting up a default [sqlite3_vfs] module, or setting up 1117** a default configuration using [sqlite3_config()]. 1118** 1119** The application should never invoke either sqlite3_os_init() 1120** or sqlite3_os_end() directly. The application should only invoke 1121** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1122** interface is called automatically by sqlite3_initialize() and 1123** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1124** implementations for sqlite3_os_init() and sqlite3_os_end() 1125** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1126** When [custom builds | built for other platforms] 1127** (using the [SQLITE_OS_OTHER=1] compile-time 1128** option) the application must supply a suitable implementation for 1129** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1130** implementation of sqlite3_os_init() or sqlite3_os_end() 1131** must return [SQLITE_OK] on success and some other [error code] upon 1132** failure. 1133*/ 1134SQLITE_API int sqlite3_initialize(void); 1135SQLITE_API int sqlite3_shutdown(void); 1136SQLITE_API int sqlite3_os_init(void); 1137SQLITE_API int sqlite3_os_end(void); 1138 1139/* 1140** CAPI3REF: Configuring The SQLite Library 1141** 1142** The sqlite3_config() interface is used to make global configuration 1143** changes to SQLite in order to tune SQLite to the specific needs of 1144** the application. The default configuration is recommended for most 1145** applications and so this routine is usually not necessary. It is 1146** provided to support rare applications with unusual needs. 1147** 1148** The sqlite3_config() interface is not threadsafe. The application 1149** must insure that no other SQLite interfaces are invoked by other 1150** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1151** may only be invoked prior to library initialization using 1152** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1153** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1154** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1155** Note, however, that ^sqlite3_config() can be called as part of the 1156** implementation of an application-defined [sqlite3_os_init()]. 1157** 1158** The first argument to sqlite3_config() is an integer 1159** [configuration option] that determines 1160** what property of SQLite is to be configured. Subsequent arguments 1161** vary depending on the [configuration option] 1162** in the first argument. 1163** 1164** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1165** ^If the option is unknown or SQLite is unable to set the option 1166** then this routine returns a non-zero [error code]. 1167*/ 1168SQLITE_API int sqlite3_config(int, ...); 1169 1170/* 1171** CAPI3REF: Configure database connections 1172** 1173** The sqlite3_db_config() interface is used to make configuration 1174** changes to a [database connection]. The interface is similar to 1175** [sqlite3_config()] except that the changes apply to a single 1176** [database connection] (specified in the first argument). 1177** 1178** The second argument to sqlite3_db_config(D,V,...) is the 1179** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1180** that indicates what aspect of the [database connection] is being configured. 1181** Subsequent arguments vary depending on the configuration verb. 1182** 1183** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1184** the call is considered successful. 1185*/ 1186SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...); 1187 1188/* 1189** CAPI3REF: Memory Allocation Routines 1190** 1191** An instance of this object defines the interface between SQLite 1192** and low-level memory allocation routines. 1193** 1194** This object is used in only one place in the SQLite interface. 1195** A pointer to an instance of this object is the argument to 1196** [sqlite3_config()] when the configuration option is 1197** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1198** By creating an instance of this object 1199** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1200** during configuration, an application can specify an alternative 1201** memory allocation subsystem for SQLite to use for all of its 1202** dynamic memory needs. 1203** 1204** Note that SQLite comes with several [built-in memory allocators] 1205** that are perfectly adequate for the overwhelming majority of applications 1206** and that this object is only useful to a tiny minority of applications 1207** with specialized memory allocation requirements. This object is 1208** also used during testing of SQLite in order to specify an alternative 1209** memory allocator that simulates memory out-of-memory conditions in 1210** order to verify that SQLite recovers gracefully from such 1211** conditions. 1212** 1213** The xMalloc, xRealloc, and xFree methods must work like the 1214** malloc(), realloc() and free() functions from the standard C library. 1215** ^SQLite guarantees that the second argument to 1216** xRealloc is always a value returned by a prior call to xRoundup. 1217** 1218** xSize should return the allocated size of a memory allocation 1219** previously obtained from xMalloc or xRealloc. The allocated size 1220** is always at least as big as the requested size but may be larger. 1221** 1222** The xRoundup method returns what would be the allocated size of 1223** a memory allocation given a particular requested size. Most memory 1224** allocators round up memory allocations at least to the next multiple 1225** of 8. Some allocators round up to a larger multiple or to a power of 2. 1226** Every memory allocation request coming in through [sqlite3_malloc()] 1227** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1228** that causes the corresponding memory allocation to fail. 1229** 1230** The xInit method initializes the memory allocator. (For example, 1231** it might allocate any require mutexes or initialize internal data 1232** structures. The xShutdown method is invoked (indirectly) by 1233** [sqlite3_shutdown()] and should deallocate any resources acquired 1234** by xInit. The pAppData pointer is used as the only parameter to 1235** xInit and xShutdown. 1236** 1237** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1238** the xInit method, so the xInit method need not be threadsafe. The 1239** xShutdown method is only called from [sqlite3_shutdown()] so it does 1240** not need to be threadsafe either. For all other methods, SQLite 1241** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1242** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1243** it is by default) and so the methods are automatically serialized. 1244** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1245** methods must be threadsafe or else make their own arrangements for 1246** serialization. 1247** 1248** SQLite will never invoke xInit() more than once without an intervening 1249** call to xShutdown(). 1250*/ 1251typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1252struct sqlite3_mem_methods { 1253 void *(*xMalloc)(int); /* Memory allocation function */ 1254 void (*xFree)(void*); /* Free a prior allocation */ 1255 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1256 int (*xSize)(void*); /* Return the size of an allocation */ 1257 int (*xRoundup)(int); /* Round up request size to allocation size */ 1258 int (*xInit)(void*); /* Initialize the memory allocator */ 1259 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1260 void *pAppData; /* Argument to xInit() and xShutdown() */ 1261}; 1262 1263/* 1264** CAPI3REF: Configuration Options 1265** KEYWORDS: {configuration option} 1266** 1267** These constants are the available integer configuration options that 1268** can be passed as the first argument to the [sqlite3_config()] interface. 1269** 1270** New configuration options may be added in future releases of SQLite. 1271** Existing configuration options might be discontinued. Applications 1272** should check the return code from [sqlite3_config()] to make sure that 1273** the call worked. The [sqlite3_config()] interface will return a 1274** non-zero [error code] if a discontinued or unsupported configuration option 1275** is invoked. 1276** 1277** <dl> 1278** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1279** <dd>There are no arguments to this option. ^This option sets the 1280** [threading mode] to Single-thread. In other words, it disables 1281** all mutexing and puts SQLite into a mode where it can only be used 1282** by a single thread. ^If SQLite is compiled with 1283** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1284** it is not possible to change the [threading mode] from its default 1285** value of Single-thread and so [sqlite3_config()] will return 1286** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1287** configuration option.</dd> 1288** 1289** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1290** <dd>There are no arguments to this option. ^This option sets the 1291** [threading mode] to Multi-thread. In other words, it disables 1292** mutexing on [database connection] and [prepared statement] objects. 1293** The application is responsible for serializing access to 1294** [database connections] and [prepared statements]. But other mutexes 1295** are enabled so that SQLite will be safe to use in a multi-threaded 1296** environment as long as no two threads attempt to use the same 1297** [database connection] at the same time. ^If SQLite is compiled with 1298** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1299** it is not possible to set the Multi-thread [threading mode] and 1300** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1301** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1302** 1303** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1304** <dd>There are no arguments to this option. ^This option sets the 1305** [threading mode] to Serialized. In other words, this option enables 1306** all mutexes including the recursive 1307** mutexes on [database connection] and [prepared statement] objects. 1308** In this mode (which is the default when SQLite is compiled with 1309** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1310** to [database connections] and [prepared statements] so that the 1311** application is free to use the same [database connection] or the 1312** same [prepared statement] in different threads at the same time. 1313** ^If SQLite is compiled with 1314** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1315** it is not possible to set the Serialized [threading mode] and 1316** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1317** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1318** 1319** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1320** <dd> ^(This option takes a single argument which is a pointer to an 1321** instance of the [sqlite3_mem_methods] structure. The argument specifies 1322** alternative low-level memory allocation routines to be used in place of 1323** the memory allocation routines built into SQLite.)^ ^SQLite makes 1324** its own private copy of the content of the [sqlite3_mem_methods] structure 1325** before the [sqlite3_config()] call returns.</dd> 1326** 1327** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1328** <dd> ^(This option takes a single argument which is a pointer to an 1329** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1330** structure is filled with the currently defined memory allocation routines.)^ 1331** This option can be used to overload the default memory allocation 1332** routines with a wrapper that simulations memory allocation failure or 1333** tracks memory usage, for example. </dd> 1334** 1335** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1336** <dd> ^This option takes single argument of type int, interpreted as a 1337** boolean, which enables or disables the collection of memory allocation 1338** statistics. ^(When memory allocation statistics are disabled, the 1339** following SQLite interfaces become non-operational: 1340** <ul> 1341** <li> [sqlite3_memory_used()] 1342** <li> [sqlite3_memory_highwater()] 1343** <li> [sqlite3_soft_heap_limit64()] 1344** <li> [sqlite3_status()] 1345** </ul>)^ 1346** ^Memory allocation statistics are enabled by default unless SQLite is 1347** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1348** allocation statistics are disabled by default. 1349** </dd> 1350** 1351** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1352** <dd> ^This option specifies a static memory buffer that SQLite can use for 1353** scratch memory. There are three arguments: A pointer an 8-byte 1354** aligned memory buffer from which the scratch allocations will be 1355** drawn, the size of each scratch allocation (sz), 1356** and the maximum number of scratch allocations (N). The sz 1357** argument must be a multiple of 16. 1358** The first argument must be a pointer to an 8-byte aligned buffer 1359** of at least sz*N bytes of memory. 1360** ^SQLite will use no more than two scratch buffers per thread. So 1361** N should be set to twice the expected maximum number of threads. 1362** ^SQLite will never require a scratch buffer that is more than 6 1363** times the database page size. ^If SQLite needs needs additional 1364** scratch memory beyond what is provided by this configuration option, then 1365** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1366** 1367** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1368** <dd> ^This option specifies a static memory buffer that SQLite can use for 1369** the database page cache with the default page cache implementation. 1370** This configuration should not be used if an application-define page 1371** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option. 1372** There are three arguments to this option: A pointer to 8-byte aligned 1373** memory, the size of each page buffer (sz), and the number of pages (N). 1374** The sz argument should be the size of the largest database page 1375** (a power of two between 512 and 32768) plus a little extra for each 1376** page header. ^The page header size is 20 to 40 bytes depending on 1377** the host architecture. ^It is harmless, apart from the wasted memory, 1378** to make sz a little too large. The first 1379** argument should point to an allocation of at least sz*N bytes of memory. 1380** ^SQLite will use the memory provided by the first argument to satisfy its 1381** memory needs for the first N pages that it adds to cache. ^If additional 1382** page cache memory is needed beyond what is provided by this option, then 1383** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1384** The pointer in the first argument must 1385** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1386** will be undefined.</dd> 1387** 1388** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1389** <dd> ^This option specifies a static memory buffer that SQLite will use 1390** for all of its dynamic memory allocation needs beyond those provided 1391** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1392** There are three arguments: An 8-byte aligned pointer to the memory, 1393** the number of bytes in the memory buffer, and the minimum allocation size. 1394** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1395** to using its default memory allocator (the system malloc() implementation), 1396** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1397** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1398** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1399** allocator is engaged to handle all of SQLites memory allocation needs. 1400** The first pointer (the memory pointer) must be aligned to an 8-byte 1401** boundary or subsequent behavior of SQLite will be undefined. 1402** The minimum allocation size is capped at 2^12. Reasonable values 1403** for the minimum allocation size are 2^5 through 2^8.</dd> 1404** 1405** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1406** <dd> ^(This option takes a single argument which is a pointer to an 1407** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1408** alternative low-level mutex routines to be used in place 1409** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1410** content of the [sqlite3_mutex_methods] structure before the call to 1411** [sqlite3_config()] returns. ^If SQLite is compiled with 1412** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1413** the entire mutexing subsystem is omitted from the build and hence calls to 1414** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1415** return [SQLITE_ERROR].</dd> 1416** 1417** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1418** <dd> ^(This option takes a single argument which is a pointer to an 1419** instance of the [sqlite3_mutex_methods] structure. The 1420** [sqlite3_mutex_methods] 1421** structure is filled with the currently defined mutex routines.)^ 1422** This option can be used to overload the default mutex allocation 1423** routines with a wrapper used to track mutex usage for performance 1424** profiling or testing, for example. ^If SQLite is compiled with 1425** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1426** the entire mutexing subsystem is omitted from the build and hence calls to 1427** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1428** return [SQLITE_ERROR].</dd> 1429** 1430** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1431** <dd> ^(This option takes two arguments that determine the default 1432** memory allocation for the lookaside memory allocator on each 1433** [database connection]. The first argument is the 1434** size of each lookaside buffer slot and the second is the number of 1435** slots allocated to each database connection.)^ ^(This option sets the 1436** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1437** verb to [sqlite3_db_config()] can be used to change the lookaside 1438** configuration on individual connections.)^ </dd> 1439** 1440** [[SQLITE_CONFIG_PCACHE]] <dt>SQLITE_CONFIG_PCACHE</dt> 1441** <dd> ^(This option takes a single argument which is a pointer to 1442** an [sqlite3_pcache_methods] object. This object specifies the interface 1443** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1444** object and uses it for page cache memory allocations.</dd> 1445** 1446** [[SQLITE_CONFIG_GETPCACHE]] <dt>SQLITE_CONFIG_GETPCACHE</dt> 1447** <dd> ^(This option takes a single argument which is a pointer to an 1448** [sqlite3_pcache_methods] object. SQLite copies of the current 1449** page cache implementation into that object.)^ </dd> 1450** 1451** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1452** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1453** function with a call signature of void(*)(void*,int,const char*), 1454** and a pointer to void. ^If the function pointer is not NULL, it is 1455** invoked by [sqlite3_log()] to process each logging event. ^If the 1456** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1457** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1458** passed through as the first parameter to the application-defined logger 1459** function whenever that function is invoked. ^The second parameter to 1460** the logger function is a copy of the first parameter to the corresponding 1461** [sqlite3_log()] call and is intended to be a [result code] or an 1462** [extended result code]. ^The third parameter passed to the logger is 1463** log message after formatting via [sqlite3_snprintf()]. 1464** The SQLite logging interface is not reentrant; the logger function 1465** supplied by the application must not invoke any SQLite interface. 1466** In a multi-threaded application, the application-defined logger 1467** function must be threadsafe. </dd> 1468** 1469** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1470** <dd> This option takes a single argument of type int. If non-zero, then 1471** URI handling is globally enabled. If the parameter is zero, then URI handling 1472** is globally disabled. If URI handling is globally enabled, all filenames 1473** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or 1474** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1475** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1476** connection is opened. If it is globally disabled, filenames are 1477** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1478** database connection is opened. By default, URI handling is globally 1479** disabled. The default value may be changed by compiling with the 1480** [SQLITE_USE_URI] symbol defined. 1481** </dl> 1482*/ 1483#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1484#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1485#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1486#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1487#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1488#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1489#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1490#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1491#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1492#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1493#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1494/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1495#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1496#define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */ 1497#define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */ 1498#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1499#define SQLITE_CONFIG_URI 17 /* int */ 1500 1501/* 1502** CAPI3REF: Database Connection Configuration Options 1503** 1504** These constants are the available integer configuration options that 1505** can be passed as the second argument to the [sqlite3_db_config()] interface. 1506** 1507** New configuration options may be added in future releases of SQLite. 1508** Existing configuration options might be discontinued. Applications 1509** should check the return code from [sqlite3_db_config()] to make sure that 1510** the call worked. ^The [sqlite3_db_config()] interface will return a 1511** non-zero [error code] if a discontinued or unsupported configuration option 1512** is invoked. 1513** 1514** <dl> 1515** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1516** <dd> ^This option takes three additional arguments that determine the 1517** [lookaside memory allocator] configuration for the [database connection]. 1518** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1519** pointer to a memory buffer to use for lookaside memory. 1520** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1521** may be NULL in which case SQLite will allocate the 1522** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1523** size of each lookaside buffer slot. ^The third argument is the number of 1524** slots. The size of the buffer in the first argument must be greater than 1525** or equal to the product of the second and third arguments. The buffer 1526** must be aligned to an 8-byte boundary. ^If the second argument to 1527** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1528** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1529** configuration for a database connection can only be changed when that 1530** connection is not currently using lookaside memory, or in other words 1531** when the "current value" returned by 1532** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1533** Any attempt to change the lookaside memory configuration when lookaside 1534** memory is in use leaves the configuration unchanged and returns 1535** [SQLITE_BUSY].)^</dd> 1536** 1537** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1538** <dd> ^This option is used to enable or disable the enforcement of 1539** [foreign key constraints]. There should be two additional arguments. 1540** The first argument is an integer which is 0 to disable FK enforcement, 1541** positive to enable FK enforcement or negative to leave FK enforcement 1542** unchanged. The second parameter is a pointer to an integer into which 1543** is written 0 or 1 to indicate whether FK enforcement is off or on 1544** following this call. The second parameter may be a NULL pointer, in 1545** which case the FK enforcement setting is not reported back. </dd> 1546** 1547** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1548** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1549** There should be two additional arguments. 1550** The first argument is an integer which is 0 to disable triggers, 1551** positive to enable triggers or negative to leave the setting unchanged. 1552** The second parameter is a pointer to an integer into which 1553** is written 0 or 1 to indicate whether triggers are disabled or enabled 1554** following this call. The second parameter may be a NULL pointer, in 1555** which case the trigger setting is not reported back. </dd> 1556** 1557** </dl> 1558*/ 1559#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1560#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1561#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1562 1563 1564/* 1565** CAPI3REF: Enable Or Disable Extended Result Codes 1566** 1567** ^The sqlite3_extended_result_codes() routine enables or disables the 1568** [extended result codes] feature of SQLite. ^The extended result 1569** codes are disabled by default for historical compatibility. 1570*/ 1571SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff); 1572 1573/* 1574** CAPI3REF: Last Insert Rowid 1575** 1576** ^Each entry in an SQLite table has a unique 64-bit signed 1577** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1578** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1579** names are not also used by explicitly declared columns. ^If 1580** the table has a column of type [INTEGER PRIMARY KEY] then that column 1581** is another alias for the rowid. 1582** 1583** ^This routine returns the [rowid] of the most recent 1584** successful [INSERT] into the database from the [database connection] 1585** in the first argument. ^As of SQLite version 3.7.7, this routines 1586** records the last insert rowid of both ordinary tables and [virtual tables]. 1587** ^If no successful [INSERT]s 1588** have ever occurred on that database connection, zero is returned. 1589** 1590** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1591** method, then this routine will return the [rowid] of the inserted 1592** row as long as the trigger or virtual table method is running. 1593** But once the trigger or virtual table method ends, the value returned 1594** by this routine reverts to what it was before the trigger or virtual 1595** table method began.)^ 1596** 1597** ^An [INSERT] that fails due to a constraint violation is not a 1598** successful [INSERT] and does not change the value returned by this 1599** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1600** and INSERT OR ABORT make no changes to the return value of this 1601** routine when their insertion fails. ^(When INSERT OR REPLACE 1602** encounters a constraint violation, it does not fail. The 1603** INSERT continues to completion after deleting rows that caused 1604** the constraint problem so INSERT OR REPLACE will always change 1605** the return value of this interface.)^ 1606** 1607** ^For the purposes of this routine, an [INSERT] is considered to 1608** be successful even if it is subsequently rolled back. 1609** 1610** This function is accessible to SQL statements via the 1611** [last_insert_rowid() SQL function]. 1612** 1613** If a separate thread performs a new [INSERT] on the same 1614** database connection while the [sqlite3_last_insert_rowid()] 1615** function is running and thus changes the last insert [rowid], 1616** then the value returned by [sqlite3_last_insert_rowid()] is 1617** unpredictable and might not equal either the old or the new 1618** last insert [rowid]. 1619*/ 1620SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1621 1622/* 1623** CAPI3REF: Count The Number Of Rows Modified 1624** 1625** ^This function returns the number of database rows that were changed 1626** or inserted or deleted by the most recently completed SQL statement 1627** on the [database connection] specified by the first parameter. 1628** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1629** or [DELETE] statement are counted. Auxiliary changes caused by 1630** triggers or [foreign key actions] are not counted.)^ Use the 1631** [sqlite3_total_changes()] function to find the total number of changes 1632** including changes caused by triggers and foreign key actions. 1633** 1634** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1635** are not counted. Only real table changes are counted. 1636** 1637** ^(A "row change" is a change to a single row of a single table 1638** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1639** are changed as side effects of [REPLACE] constraint resolution, 1640** rollback, ABORT processing, [DROP TABLE], or by any other 1641** mechanisms do not count as direct row changes.)^ 1642** 1643** A "trigger context" is a scope of execution that begins and 1644** ends with the script of a [CREATE TRIGGER | trigger]. 1645** Most SQL statements are 1646** evaluated outside of any trigger. This is the "top level" 1647** trigger context. If a trigger fires from the top level, a 1648** new trigger context is entered for the duration of that one 1649** trigger. Subtriggers create subcontexts for their duration. 1650** 1651** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1652** not create a new trigger context. 1653** 1654** ^This function returns the number of direct row changes in the 1655** most recent INSERT, UPDATE, or DELETE statement within the same 1656** trigger context. 1657** 1658** ^Thus, when called from the top level, this function returns the 1659** number of changes in the most recent INSERT, UPDATE, or DELETE 1660** that also occurred at the top level. ^(Within the body of a trigger, 1661** the sqlite3_changes() interface can be called to find the number of 1662** changes in the most recently completed INSERT, UPDATE, or DELETE 1663** statement within the body of the same trigger. 1664** However, the number returned does not include changes 1665** caused by subtriggers since those have their own context.)^ 1666** 1667** See also the [sqlite3_total_changes()] interface, the 1668** [count_changes pragma], and the [changes() SQL function]. 1669** 1670** If a separate thread makes changes on the same database connection 1671** while [sqlite3_changes()] is running then the value returned 1672** is unpredictable and not meaningful. 1673*/ 1674SQLITE_API int sqlite3_changes(sqlite3*); 1675 1676/* 1677** CAPI3REF: Total Number Of Rows Modified 1678** 1679** ^This function returns the number of row changes caused by [INSERT], 1680** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1681** ^(The count returned by sqlite3_total_changes() includes all changes 1682** from all [CREATE TRIGGER | trigger] contexts and changes made by 1683** [foreign key actions]. However, 1684** the count does not include changes used to implement [REPLACE] constraints, 1685** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1686** count does not include rows of views that fire an [INSTEAD OF trigger], 1687** though if the INSTEAD OF trigger makes changes of its own, those changes 1688** are counted.)^ 1689** ^The sqlite3_total_changes() function counts the changes as soon as 1690** the statement that makes them is completed (when the statement handle 1691** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1692** 1693** See also the [sqlite3_changes()] interface, the 1694** [count_changes pragma], and the [total_changes() SQL function]. 1695** 1696** If a separate thread makes changes on the same database connection 1697** while [sqlite3_total_changes()] is running then the value 1698** returned is unpredictable and not meaningful. 1699*/ 1700SQLITE_API int sqlite3_total_changes(sqlite3*); 1701 1702/* 1703** CAPI3REF: Interrupt A Long-Running Query 1704** 1705** ^This function causes any pending database operation to abort and 1706** return at its earliest opportunity. This routine is typically 1707** called in response to a user action such as pressing "Cancel" 1708** or Ctrl-C where the user wants a long query operation to halt 1709** immediately. 1710** 1711** ^It is safe to call this routine from a thread different from the 1712** thread that is currently running the database operation. But it 1713** is not safe to call this routine with a [database connection] that 1714** is closed or might close before sqlite3_interrupt() returns. 1715** 1716** ^If an SQL operation is very nearly finished at the time when 1717** sqlite3_interrupt() is called, then it might not have an opportunity 1718** to be interrupted and might continue to completion. 1719** 1720** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1721** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1722** that is inside an explicit transaction, then the entire transaction 1723** will be rolled back automatically. 1724** 1725** ^The sqlite3_interrupt(D) call is in effect until all currently running 1726** SQL statements on [database connection] D complete. ^Any new SQL statements 1727** that are started after the sqlite3_interrupt() call and before the 1728** running statements reaches zero are interrupted as if they had been 1729** running prior to the sqlite3_interrupt() call. ^New SQL statements 1730** that are started after the running statement count reaches zero are 1731** not effected by the sqlite3_interrupt(). 1732** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1733** SQL statements is a no-op and has no effect on SQL statements 1734** that are started after the sqlite3_interrupt() call returns. 1735** 1736** If the database connection closes while [sqlite3_interrupt()] 1737** is running then bad things will likely happen. 1738*/ 1739SQLITE_API void sqlite3_interrupt(sqlite3*); 1740 1741/* 1742** CAPI3REF: Determine If An SQL Statement Is Complete 1743** 1744** These routines are useful during command-line input to determine if the 1745** currently entered text seems to form a complete SQL statement or 1746** if additional input is needed before sending the text into 1747** SQLite for parsing. ^These routines return 1 if the input string 1748** appears to be a complete SQL statement. ^A statement is judged to be 1749** complete if it ends with a semicolon token and is not a prefix of a 1750** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1751** string literals or quoted identifier names or comments are not 1752** independent tokens (they are part of the token in which they are 1753** embedded) and thus do not count as a statement terminator. ^Whitespace 1754** and comments that follow the final semicolon are ignored. 1755** 1756** ^These routines return 0 if the statement is incomplete. ^If a 1757** memory allocation fails, then SQLITE_NOMEM is returned. 1758** 1759** ^These routines do not parse the SQL statements thus 1760** will not detect syntactically incorrect SQL. 1761** 1762** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1763** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1764** automatically by sqlite3_complete16(). If that initialization fails, 1765** then the return value from sqlite3_complete16() will be non-zero 1766** regardless of whether or not the input SQL is complete.)^ 1767** 1768** The input to [sqlite3_complete()] must be a zero-terminated 1769** UTF-8 string. 1770** 1771** The input to [sqlite3_complete16()] must be a zero-terminated 1772** UTF-16 string in native byte order. 1773*/ 1774SQLITE_API int sqlite3_complete(const char *sql); 1775SQLITE_API int sqlite3_complete16(const void *sql); 1776 1777/* 1778** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1779** 1780** ^This routine sets a callback function that might be invoked whenever 1781** an attempt is made to open a database table that another thread 1782** or process has locked. 1783** 1784** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1785** is returned immediately upon encountering the lock. ^If the busy callback 1786** is not NULL, then the callback might be invoked with two arguments. 1787** 1788** ^The first argument to the busy handler is a copy of the void* pointer which 1789** is the third argument to sqlite3_busy_handler(). ^The second argument to 1790** the busy handler callback is the number of times that the busy handler has 1791** been invoked for this locking event. ^If the 1792** busy callback returns 0, then no additional attempts are made to 1793** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1794** ^If the callback returns non-zero, then another attempt 1795** is made to open the database for reading and the cycle repeats. 1796** 1797** The presence of a busy handler does not guarantee that it will be invoked 1798** when there is lock contention. ^If SQLite determines that invoking the busy 1799** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1800** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1801** Consider a scenario where one process is holding a read lock that 1802** it is trying to promote to a reserved lock and 1803** a second process is holding a reserved lock that it is trying 1804** to promote to an exclusive lock. The first process cannot proceed 1805** because it is blocked by the second and the second process cannot 1806** proceed because it is blocked by the first. If both processes 1807** invoke the busy handlers, neither will make any progress. Therefore, 1808** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1809** will induce the first process to release its read lock and allow 1810** the second process to proceed. 1811** 1812** ^The default busy callback is NULL. 1813** 1814** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1815** when SQLite is in the middle of a large transaction where all the 1816** changes will not fit into the in-memory cache. SQLite will 1817** already hold a RESERVED lock on the database file, but it needs 1818** to promote this lock to EXCLUSIVE so that it can spill cache 1819** pages into the database file without harm to concurrent 1820** readers. ^If it is unable to promote the lock, then the in-memory 1821** cache will be left in an inconsistent state and so the error 1822** code is promoted from the relatively benign [SQLITE_BUSY] to 1823** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 1824** forces an automatic rollback of the changes. See the 1825** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1826** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1827** this is important. 1828** 1829** ^(There can only be a single busy handler defined for each 1830** [database connection]. Setting a new busy handler clears any 1831** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 1832** will also set or clear the busy handler. 1833** 1834** The busy callback should not take any actions which modify the 1835** database connection that invoked the busy handler. Any such actions 1836** result in undefined behavior. 1837** 1838** A busy handler must not close the database connection 1839** or [prepared statement] that invoked the busy handler. 1840*/ 1841SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1842 1843/* 1844** CAPI3REF: Set A Busy Timeout 1845** 1846** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1847** for a specified amount of time when a table is locked. ^The handler 1848** will sleep multiple times until at least "ms" milliseconds of sleeping 1849** have accumulated. ^After at least "ms" milliseconds of sleeping, 1850** the handler returns 0 which causes [sqlite3_step()] to return 1851** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1852** 1853** ^Calling this routine with an argument less than or equal to zero 1854** turns off all busy handlers. 1855** 1856** ^(There can only be a single busy handler for a particular 1857** [database connection] any any given moment. If another busy handler 1858** was defined (using [sqlite3_busy_handler()]) prior to calling 1859** this routine, that other busy handler is cleared.)^ 1860*/ 1861SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms); 1862 1863/* 1864** CAPI3REF: Convenience Routines For Running Queries 1865** 1866** This is a legacy interface that is preserved for backwards compatibility. 1867** Use of this interface is not recommended. 1868** 1869** Definition: A <b>result table</b> is memory data structure created by the 1870** [sqlite3_get_table()] interface. A result table records the 1871** complete query results from one or more queries. 1872** 1873** The table conceptually has a number of rows and columns. But 1874** these numbers are not part of the result table itself. These 1875** numbers are obtained separately. Let N be the number of rows 1876** and M be the number of columns. 1877** 1878** A result table is an array of pointers to zero-terminated UTF-8 strings. 1879** There are (N+1)*M elements in the array. The first M pointers point 1880** to zero-terminated strings that contain the names of the columns. 1881** The remaining entries all point to query results. NULL values result 1882** in NULL pointers. All other values are in their UTF-8 zero-terminated 1883** string representation as returned by [sqlite3_column_text()]. 1884** 1885** A result table might consist of one or more memory allocations. 1886** It is not safe to pass a result table directly to [sqlite3_free()]. 1887** A result table should be deallocated using [sqlite3_free_table()]. 1888** 1889** ^(As an example of the result table format, suppose a query result 1890** is as follows: 1891** 1892** <blockquote><pre> 1893** Name | Age 1894** ----------------------- 1895** Alice | 43 1896** Bob | 28 1897** Cindy | 21 1898** </pre></blockquote> 1899** 1900** There are two column (M==2) and three rows (N==3). Thus the 1901** result table has 8 entries. Suppose the result table is stored 1902** in an array names azResult. Then azResult holds this content: 1903** 1904** <blockquote><pre> 1905** azResult[0] = "Name"; 1906** azResult[1] = "Age"; 1907** azResult[2] = "Alice"; 1908** azResult[3] = "43"; 1909** azResult[4] = "Bob"; 1910** azResult[5] = "28"; 1911** azResult[6] = "Cindy"; 1912** azResult[7] = "21"; 1913** </pre></blockquote>)^ 1914** 1915** ^The sqlite3_get_table() function evaluates one or more 1916** semicolon-separated SQL statements in the zero-terminated UTF-8 1917** string of its 2nd parameter and returns a result table to the 1918** pointer given in its 3rd parameter. 1919** 1920** After the application has finished with the result from sqlite3_get_table(), 1921** it must pass the result table pointer to sqlite3_free_table() in order to 1922** release the memory that was malloced. Because of the way the 1923** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1924** function must not try to call [sqlite3_free()] directly. Only 1925** [sqlite3_free_table()] is able to release the memory properly and safely. 1926** 1927** The sqlite3_get_table() interface is implemented as a wrapper around 1928** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 1929** to any internal data structures of SQLite. It uses only the public 1930** interface defined here. As a consequence, errors that occur in the 1931** wrapper layer outside of the internal [sqlite3_exec()] call are not 1932** reflected in subsequent calls to [sqlite3_errcode()] or 1933** [sqlite3_errmsg()]. 1934*/ 1935SQLITE_API int sqlite3_get_table( 1936 sqlite3 *db, /* An open database */ 1937 const char *zSql, /* SQL to be evaluated */ 1938 char ***pazResult, /* Results of the query */ 1939 int *pnRow, /* Number of result rows written here */ 1940 int *pnColumn, /* Number of result columns written here */ 1941 char **pzErrmsg /* Error msg written here */ 1942); 1943SQLITE_API void sqlite3_free_table(char **result); 1944 1945/* 1946** CAPI3REF: Formatted String Printing Functions 1947** 1948** These routines are work-alikes of the "printf()" family of functions 1949** from the standard C library. 1950** 1951** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 1952** results into memory obtained from [sqlite3_malloc()]. 1953** The strings returned by these two routines should be 1954** released by [sqlite3_free()]. ^Both routines return a 1955** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 1956** memory to hold the resulting string. 1957** 1958** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 1959** the standard C library. The result is written into the 1960** buffer supplied as the second parameter whose size is given by 1961** the first parameter. Note that the order of the 1962** first two parameters is reversed from snprintf().)^ This is an 1963** historical accident that cannot be fixed without breaking 1964** backwards compatibility. ^(Note also that sqlite3_snprintf() 1965** returns a pointer to its buffer instead of the number of 1966** characters actually written into the buffer.)^ We admit that 1967** the number of characters written would be a more useful return 1968** value but we cannot change the implementation of sqlite3_snprintf() 1969** now without breaking compatibility. 1970** 1971** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 1972** guarantees that the buffer is always zero-terminated. ^The first 1973** parameter "n" is the total size of the buffer, including space for 1974** the zero terminator. So the longest string that can be completely 1975** written will be n-1 characters. 1976** 1977** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 1978** 1979** These routines all implement some additional formatting 1980** options that are useful for constructing SQL statements. 1981** All of the usual printf() formatting options apply. In addition, there 1982** is are "%q", "%Q", and "%z" options. 1983** 1984** ^(The %q option works like %s in that it substitutes a null-terminated 1985** string from the argument list. But %q also doubles every '\'' character. 1986** %q is designed for use inside a string literal.)^ By doubling each '\'' 1987** character it escapes that character and allows it to be inserted into 1988** the string. 1989** 1990** For example, assume the string variable zText contains text as follows: 1991** 1992** <blockquote><pre> 1993** char *zText = "It's a happy day!"; 1994** </pre></blockquote> 1995** 1996** One can use this text in an SQL statement as follows: 1997** 1998** <blockquote><pre> 1999** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2000** sqlite3_exec(db, zSQL, 0, 0, 0); 2001** sqlite3_free(zSQL); 2002** </pre></blockquote> 2003** 2004** Because the %q format string is used, the '\'' character in zText 2005** is escaped and the SQL generated is as follows: 2006** 2007** <blockquote><pre> 2008** INSERT INTO table1 VALUES('It''s a happy day!') 2009** </pre></blockquote> 2010** 2011** This is correct. Had we used %s instead of %q, the generated SQL 2012** would have looked like this: 2013** 2014** <blockquote><pre> 2015** INSERT INTO table1 VALUES('It's a happy day!'); 2016** </pre></blockquote> 2017** 2018** This second example is an SQL syntax error. As a general rule you should 2019** always use %q instead of %s when inserting text into a string literal. 2020** 2021** ^(The %Q option works like %q except it also adds single quotes around 2022** the outside of the total string. Additionally, if the parameter in the 2023** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2024** single quotes).)^ So, for example, one could say: 2025** 2026** <blockquote><pre> 2027** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2028** sqlite3_exec(db, zSQL, 0, 0, 0); 2029** sqlite3_free(zSQL); 2030** </pre></blockquote> 2031** 2032** The code above will render a correct SQL statement in the zSQL 2033** variable even if the zText variable is a NULL pointer. 2034** 2035** ^(The "%z" formatting option works like "%s" but with the 2036** addition that after the string has been read and copied into 2037** the result, [sqlite3_free()] is called on the input string.)^ 2038*/ 2039SQLITE_API char *sqlite3_mprintf(const char*,...); 2040SQLITE_API char *sqlite3_vmprintf(const char*, va_list); 2041SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...); 2042SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2043 2044/* 2045** CAPI3REF: Memory Allocation Subsystem 2046** 2047** The SQLite core uses these three routines for all of its own 2048** internal memory allocation needs. "Core" in the previous sentence 2049** does not include operating-system specific VFS implementation. The 2050** Windows VFS uses native malloc() and free() for some operations. 2051** 2052** ^The sqlite3_malloc() routine returns a pointer to a block 2053** of memory at least N bytes in length, where N is the parameter. 2054** ^If sqlite3_malloc() is unable to obtain sufficient free 2055** memory, it returns a NULL pointer. ^If the parameter N to 2056** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2057** a NULL pointer. 2058** 2059** ^Calling sqlite3_free() with a pointer previously returned 2060** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2061** that it might be reused. ^The sqlite3_free() routine is 2062** a no-op if is called with a NULL pointer. Passing a NULL pointer 2063** to sqlite3_free() is harmless. After being freed, memory 2064** should neither be read nor written. Even reading previously freed 2065** memory might result in a segmentation fault or other severe error. 2066** Memory corruption, a segmentation fault, or other severe error 2067** might result if sqlite3_free() is called with a non-NULL pointer that 2068** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2069** 2070** ^(The sqlite3_realloc() interface attempts to resize a 2071** prior memory allocation to be at least N bytes, where N is the 2072** second parameter. The memory allocation to be resized is the first 2073** parameter.)^ ^ If the first parameter to sqlite3_realloc() 2074** is a NULL pointer then its behavior is identical to calling 2075** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 2076** ^If the second parameter to sqlite3_realloc() is zero or 2077** negative then the behavior is exactly the same as calling 2078** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 2079** ^sqlite3_realloc() returns a pointer to a memory allocation 2080** of at least N bytes in size or NULL if sufficient memory is unavailable. 2081** ^If M is the size of the prior allocation, then min(N,M) bytes 2082** of the prior allocation are copied into the beginning of buffer returned 2083** by sqlite3_realloc() and the prior allocation is freed. 2084** ^If sqlite3_realloc() returns NULL, then the prior allocation 2085** is not freed. 2086** 2087** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 2088** is always aligned to at least an 8 byte boundary, or to a 2089** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2090** option is used. 2091** 2092** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2093** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2094** implementation of these routines to be omitted. That capability 2095** is no longer provided. Only built-in memory allocators can be used. 2096** 2097** The Windows OS interface layer calls 2098** the system malloc() and free() directly when converting 2099** filenames between the UTF-8 encoding used by SQLite 2100** and whatever filename encoding is used by the particular Windows 2101** installation. Memory allocation errors are detected, but 2102** they are reported back as [SQLITE_CANTOPEN] or 2103** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2104** 2105** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2106** must be either NULL or else pointers obtained from a prior 2107** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2108** not yet been released. 2109** 2110** The application must not read or write any part of 2111** a block of memory after it has been released using 2112** [sqlite3_free()] or [sqlite3_realloc()]. 2113*/ 2114SQLITE_API void *sqlite3_malloc(int); 2115SQLITE_API void *sqlite3_realloc(void*, int); 2116SQLITE_API void sqlite3_free(void*); 2117 2118/* 2119** CAPI3REF: Memory Allocator Statistics 2120** 2121** SQLite provides these two interfaces for reporting on the status 2122** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2123** routines, which form the built-in memory allocation subsystem. 2124** 2125** ^The [sqlite3_memory_used()] routine returns the number of bytes 2126** of memory currently outstanding (malloced but not freed). 2127** ^The [sqlite3_memory_highwater()] routine returns the maximum 2128** value of [sqlite3_memory_used()] since the high-water mark 2129** was last reset. ^The values returned by [sqlite3_memory_used()] and 2130** [sqlite3_memory_highwater()] include any overhead 2131** added by SQLite in its implementation of [sqlite3_malloc()], 2132** but not overhead added by the any underlying system library 2133** routines that [sqlite3_malloc()] may call. 2134** 2135** ^The memory high-water mark is reset to the current value of 2136** [sqlite3_memory_used()] if and only if the parameter to 2137** [sqlite3_memory_highwater()] is true. ^The value returned 2138** by [sqlite3_memory_highwater(1)] is the high-water mark 2139** prior to the reset. 2140*/ 2141SQLITE_API sqlite3_int64 sqlite3_memory_used(void); 2142SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2143 2144/* 2145** CAPI3REF: Pseudo-Random Number Generator 2146** 2147** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2148** select random [ROWID | ROWIDs] when inserting new records into a table that 2149** already uses the largest possible [ROWID]. The PRNG is also used for 2150** the build-in random() and randomblob() SQL functions. This interface allows 2151** applications to access the same PRNG for other purposes. 2152** 2153** ^A call to this routine stores N bytes of randomness into buffer P. 2154** 2155** ^The first time this routine is invoked (either internally or by 2156** the application) the PRNG is seeded using randomness obtained 2157** from the xRandomness method of the default [sqlite3_vfs] object. 2158** ^On all subsequent invocations, the pseudo-randomness is generated 2159** internally and without recourse to the [sqlite3_vfs] xRandomness 2160** method. 2161*/ 2162SQLITE_API void sqlite3_randomness(int N, void *P); 2163 2164/* 2165** CAPI3REF: Compile-Time Authorization Callbacks 2166** 2167** ^This routine registers an authorizer callback with a particular 2168** [database connection], supplied in the first argument. 2169** ^The authorizer callback is invoked as SQL statements are being compiled 2170** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2171** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2172** points during the compilation process, as logic is being created 2173** to perform various actions, the authorizer callback is invoked to 2174** see if those actions are allowed. ^The authorizer callback should 2175** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2176** specific action but allow the SQL statement to continue to be 2177** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2178** rejected with an error. ^If the authorizer callback returns 2179** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2180** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2181** the authorizer will fail with an error message. 2182** 2183** When the callback returns [SQLITE_OK], that means the operation 2184** requested is ok. ^When the callback returns [SQLITE_DENY], the 2185** [sqlite3_prepare_v2()] or equivalent call that triggered the 2186** authorizer will fail with an error message explaining that 2187** access is denied. 2188** 2189** ^The first parameter to the authorizer callback is a copy of the third 2190** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2191** to the callback is an integer [SQLITE_COPY | action code] that specifies 2192** the particular action to be authorized. ^The third through sixth parameters 2193** to the callback are zero-terminated strings that contain additional 2194** details about the action to be authorized. 2195** 2196** ^If the action code is [SQLITE_READ] 2197** and the callback returns [SQLITE_IGNORE] then the 2198** [prepared statement] statement is constructed to substitute 2199** a NULL value in place of the table column that would have 2200** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2201** return can be used to deny an untrusted user access to individual 2202** columns of a table. 2203** ^If the action code is [SQLITE_DELETE] and the callback returns 2204** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2205** [truncate optimization] is disabled and all rows are deleted individually. 2206** 2207** An authorizer is used when [sqlite3_prepare | preparing] 2208** SQL statements from an untrusted source, to ensure that the SQL statements 2209** do not try to access data they are not allowed to see, or that they do not 2210** try to execute malicious statements that damage the database. For 2211** example, an application may allow a user to enter arbitrary 2212** SQL queries for evaluation by a database. But the application does 2213** not want the user to be able to make arbitrary changes to the 2214** database. An authorizer could then be put in place while the 2215** user-entered SQL is being [sqlite3_prepare | prepared] that 2216** disallows everything except [SELECT] statements. 2217** 2218** Applications that need to process SQL from untrusted sources 2219** might also consider lowering resource limits using [sqlite3_limit()] 2220** and limiting database size using the [max_page_count] [PRAGMA] 2221** in addition to using an authorizer. 2222** 2223** ^(Only a single authorizer can be in place on a database connection 2224** at a time. Each call to sqlite3_set_authorizer overrides the 2225** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2226** The authorizer is disabled by default. 2227** 2228** The authorizer callback must not do anything that will modify 2229** the database connection that invoked the authorizer callback. 2230** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2231** database connections for the meaning of "modify" in this paragraph. 2232** 2233** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2234** statement might be re-prepared during [sqlite3_step()] due to a 2235** schema change. Hence, the application should ensure that the 2236** correct authorizer callback remains in place during the [sqlite3_step()]. 2237** 2238** ^Note that the authorizer callback is invoked only during 2239** [sqlite3_prepare()] or its variants. Authorization is not 2240** performed during statement evaluation in [sqlite3_step()], unless 2241** as stated in the previous paragraph, sqlite3_step() invokes 2242** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2243*/ 2244SQLITE_API int sqlite3_set_authorizer( 2245 sqlite3*, 2246 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2247 void *pUserData 2248); 2249 2250/* 2251** CAPI3REF: Authorizer Return Codes 2252** 2253** The [sqlite3_set_authorizer | authorizer callback function] must 2254** return either [SQLITE_OK] or one of these two constants in order 2255** to signal SQLite whether or not the action is permitted. See the 2256** [sqlite3_set_authorizer | authorizer documentation] for additional 2257** information. 2258** 2259** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code] 2260** from the [sqlite3_vtab_on_conflict()] interface. 2261*/ 2262#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2263#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2264 2265/* 2266** CAPI3REF: Authorizer Action Codes 2267** 2268** The [sqlite3_set_authorizer()] interface registers a callback function 2269** that is invoked to authorize certain SQL statement actions. The 2270** second parameter to the callback is an integer code that specifies 2271** what action is being authorized. These are the integer action codes that 2272** the authorizer callback may be passed. 2273** 2274** These action code values signify what kind of operation is to be 2275** authorized. The 3rd and 4th parameters to the authorization 2276** callback function will be parameters or NULL depending on which of these 2277** codes is used as the second parameter. ^(The 5th parameter to the 2278** authorizer callback is the name of the database ("main", "temp", 2279** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2280** is the name of the inner-most trigger or view that is responsible for 2281** the access attempt or NULL if this access attempt is directly from 2282** top-level SQL code. 2283*/ 2284/******************************************* 3rd ************ 4th ***********/ 2285#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2286#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2287#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2288#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2289#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2290#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2291#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2292#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2293#define SQLITE_DELETE 9 /* Table Name NULL */ 2294#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2295#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2296#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2297#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2298#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2299#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2300#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2301#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2302#define SQLITE_INSERT 18 /* Table Name NULL */ 2303#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2304#define SQLITE_READ 20 /* Table Name Column Name */ 2305#define SQLITE_SELECT 21 /* NULL NULL */ 2306#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2307#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2308#define SQLITE_ATTACH 24 /* Filename NULL */ 2309#define SQLITE_DETACH 25 /* Database Name NULL */ 2310#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2311#define SQLITE_REINDEX 27 /* Index Name NULL */ 2312#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2313#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2314#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2315#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2316#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2317#define SQLITE_COPY 0 /* No longer used */ 2318 2319/* 2320** CAPI3REF: Tracing And Profiling Functions 2321** 2322** These routines register callback functions that can be used for 2323** tracing and profiling the execution of SQL statements. 2324** 2325** ^The callback function registered by sqlite3_trace() is invoked at 2326** various times when an SQL statement is being run by [sqlite3_step()]. 2327** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2328** SQL statement text as the statement first begins executing. 2329** ^(Additional sqlite3_trace() callbacks might occur 2330** as each triggered subprogram is entered. The callbacks for triggers 2331** contain a UTF-8 SQL comment that identifies the trigger.)^ 2332** 2333** ^The callback function registered by sqlite3_profile() is invoked 2334** as each SQL statement finishes. ^The profile callback contains 2335** the original statement text and an estimate of wall-clock time 2336** of how long that statement took to run. ^The profile callback 2337** time is in units of nanoseconds, however the current implementation 2338** is only capable of millisecond resolution so the six least significant 2339** digits in the time are meaningless. Future versions of SQLite 2340** might provide greater resolution on the profiler callback. The 2341** sqlite3_profile() function is considered experimental and is 2342** subject to change in future versions of SQLite. 2343*/ 2344SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2345SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2346 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2347 2348/* 2349** CAPI3REF: Query Progress Callbacks 2350** 2351** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2352** function X to be invoked periodically during long running calls to 2353** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2354** database connection D. An example use for this 2355** interface is to keep a GUI updated during a large query. 2356** 2357** ^The parameter P is passed through as the only parameter to the 2358** callback function X. ^The parameter N is the number of 2359** [virtual machine instructions] that are evaluated between successive 2360** invocations of the callback X. 2361** 2362** ^Only a single progress handler may be defined at one time per 2363** [database connection]; setting a new progress handler cancels the 2364** old one. ^Setting parameter X to NULL disables the progress handler. 2365** ^The progress handler is also disabled by setting N to a value less 2366** than 1. 2367** 2368** ^If the progress callback returns non-zero, the operation is 2369** interrupted. This feature can be used to implement a 2370** "Cancel" button on a GUI progress dialog box. 2371** 2372** The progress handler callback must not do anything that will modify 2373** the database connection that invoked the progress handler. 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*/ 2378SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2379 2380/* 2381** CAPI3REF: Opening A New Database Connection 2382** 2383** ^These routines open an SQLite database file as specified by the 2384** filename argument. ^The filename argument is interpreted as UTF-8 for 2385** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2386** order for sqlite3_open16(). ^(A [database connection] handle is usually 2387** returned in *ppDb, even if an error occurs. The only exception is that 2388** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2389** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2390** object.)^ ^(If the database is opened (and/or created) successfully, then 2391** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2392** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2393** an English language description of the error following a failure of any 2394** of the sqlite3_open() routines. 2395** 2396** ^The default encoding for the database will be UTF-8 if 2397** sqlite3_open() or sqlite3_open_v2() is called and 2398** UTF-16 in the native byte order if sqlite3_open16() is used. 2399** 2400** Whether or not an error occurs when it is opened, resources 2401** associated with the [database connection] handle should be released by 2402** passing it to [sqlite3_close()] when it is no longer required. 2403** 2404** The sqlite3_open_v2() interface works like sqlite3_open() 2405** except that it accepts two additional parameters for additional control 2406** over the new database connection. ^(The flags parameter to 2407** sqlite3_open_v2() can take one of 2408** the following three values, optionally combined with the 2409** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2410** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2411** 2412** <dl> 2413** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2414** <dd>The database is opened in read-only mode. If the database does not 2415** already exist, an error is returned.</dd>)^ 2416** 2417** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2418** <dd>The database is opened for reading and writing if possible, or reading 2419** only if the file is write protected by the operating system. In either 2420** case the database must already exist, otherwise an error is returned.</dd>)^ 2421** 2422** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2423** <dd>The database is opened for reading and writing, and is created if 2424** it does not already exist. This is the behavior that is always used for 2425** sqlite3_open() and sqlite3_open16().</dd>)^ 2426** </dl> 2427** 2428** If the 3rd parameter to sqlite3_open_v2() is not one of the 2429** combinations shown above optionally combined with other 2430** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2431** then the behavior is undefined. 2432** 2433** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2434** opens in the multi-thread [threading mode] as long as the single-thread 2435** mode has not been set at compile-time or start-time. ^If the 2436** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2437** in the serialized [threading mode] unless single-thread was 2438** previously selected at compile-time or start-time. 2439** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2440** eligible to use [shared cache mode], regardless of whether or not shared 2441** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2442** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2443** participate in [shared cache mode] even if it is enabled. 2444** 2445** ^The fourth parameter to sqlite3_open_v2() is the name of the 2446** [sqlite3_vfs] object that defines the operating system interface that 2447** the new database connection should use. ^If the fourth parameter is 2448** a NULL pointer then the default [sqlite3_vfs] object is used. 2449** 2450** ^If the filename is ":memory:", then a private, temporary in-memory database 2451** is created for the connection. ^This in-memory database will vanish when 2452** the database connection is closed. Future versions of SQLite might 2453** make use of additional special filenames that begin with the ":" character. 2454** It is recommended that when a database filename actually does begin with 2455** a ":" character you should prefix the filename with a pathname such as 2456** "./" to avoid ambiguity. 2457** 2458** ^If the filename is an empty string, then a private, temporary 2459** on-disk database will be created. ^This private database will be 2460** automatically deleted as soon as the database connection is closed. 2461** 2462** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2463** 2464** ^If [URI filename] interpretation is enabled, and the filename argument 2465** begins with "file:", then the filename is interpreted as a URI. ^URI 2466** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2467** set in the fourth argument to sqlite3_open_v2(), or if it has 2468** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2469** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2470** As of SQLite version 3.7.7, URI filename interpretation is turned off 2471** by default, but future releases of SQLite might enable URI filename 2472** interpretation by default. See "[URI filenames]" for additional 2473** information. 2474** 2475** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2476** authority, then it must be either an empty string or the string 2477** "localhost". ^If the authority is not an empty string or "localhost", an 2478** error is returned to the caller. ^The fragment component of a URI, if 2479** present, is ignored. 2480** 2481** ^SQLite uses the path component of the URI as the name of the disk file 2482** which contains the database. ^If the path begins with a '/' character, 2483** then it is interpreted as an absolute path. ^If the path does not begin 2484** with a '/' (meaning that the authority section is omitted from the URI) 2485** then the path is interpreted as a relative path. 2486** ^On windows, the first component of an absolute path 2487** is a drive specification (e.g. "C:"). 2488** 2489** [[core URI query parameters]] 2490** The query component of a URI may contain parameters that are interpreted 2491** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2492** SQLite interprets the following three query parameters: 2493** 2494** <ul> 2495** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2496** a VFS object that provides the operating system interface that should 2497** be used to access the database file on disk. ^If this option is set to 2498** an empty string the default VFS object is used. ^Specifying an unknown 2499** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2500** present, then the VFS specified by the option takes precedence over 2501** the value passed as the fourth parameter to sqlite3_open_v2(). 2502** 2503** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw" or 2504** "rwc". Attempting to set it to any other value is an error)^. 2505** ^If "ro" is specified, then the database is opened for read-only 2506** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2507** third argument to sqlite3_prepare_v2(). ^If the mode option is set to 2508** "rw", then the database is opened for read-write (but not create) 2509** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2510** been set. ^Value "rwc" is equivalent to setting both 2511** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If sqlite3_open_v2() is 2512** used, it is an error to specify a value for the mode parameter that is 2513** less restrictive than that specified by the flags passed as the third 2514** parameter. 2515** 2516** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2517** "private". ^Setting it to "shared" is equivalent to setting the 2518** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2519** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2520** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2521** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2522** a URI filename, its value overrides any behaviour requested by setting 2523** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2524** </ul> 2525** 2526** ^Specifying an unknown parameter in the query component of a URI is not an 2527** error. Future versions of SQLite might understand additional query 2528** parameters. See "[query parameters with special meaning to SQLite]" for 2529** additional information. 2530** 2531** [[URI filename examples]] <h3>URI filename examples</h3> 2532** 2533** <table border="1" align=center cellpadding=5> 2534** <tr><th> URI filenames <th> Results 2535** <tr><td> file:data.db <td> 2536** Open the file "data.db" in the current directory. 2537** <tr><td> file:/home/fred/data.db<br> 2538** file:///home/fred/data.db <br> 2539** file://localhost/home/fred/data.db <br> <td> 2540** Open the database file "/home/fred/data.db". 2541** <tr><td> file://darkstar/home/fred/data.db <td> 2542** An error. "darkstar" is not a recognized authority. 2543** <tr><td style="white-space:nowrap"> 2544** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2545** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2546** C:. Note that the %20 escaping in this example is not strictly 2547** necessary - space characters can be used literally 2548** in URI filenames. 2549** <tr><td> file:data.db?mode=ro&cache=private <td> 2550** Open file "data.db" in the current directory for read-only access. 2551** Regardless of whether or not shared-cache mode is enabled by 2552** default, use a private cache. 2553** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td> 2554** Open file "/home/fred/data.db". Use the special VFS "unix-nolock". 2555** <tr><td> file:data.db?mode=readonly <td> 2556** An error. "readonly" is not a valid option for the "mode" parameter. 2557** </table> 2558** 2559** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2560** query components of a URI. A hexadecimal escape sequence consists of a 2561** percent sign - "%" - followed by exactly two hexadecimal digits 2562** specifying an octet value. ^Before the path or query components of a 2563** URI filename are interpreted, they are encoded using UTF-8 and all 2564** hexadecimal escape sequences replaced by a single byte containing the 2565** corresponding octet. If this process generates an invalid UTF-8 encoding, 2566** the results are undefined. 2567** 2568** <b>Note to Windows users:</b> The encoding used for the filename argument 2569** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2570** codepage is currently defined. Filenames containing international 2571** characters must be converted to UTF-8 prior to passing them into 2572** sqlite3_open() or sqlite3_open_v2(). 2573*/ 2574SQLITE_API int sqlite3_open( 2575 const char *filename, /* Database filename (UTF-8) */ 2576 sqlite3 **ppDb /* OUT: SQLite db handle */ 2577); 2578SQLITE_API int sqlite3_open16( 2579 const void *filename, /* Database filename (UTF-16) */ 2580 sqlite3 **ppDb /* OUT: SQLite db handle */ 2581); 2582SQLITE_API int sqlite3_open_v2( 2583 const char *filename, /* Database filename (UTF-8) */ 2584 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2585 int flags, /* Flags */ 2586 const char *zVfs /* Name of VFS module to use */ 2587); 2588 2589/* 2590** CAPI3REF: Obtain Values For URI Parameters 2591** 2592** This is a utility routine, useful to VFS implementations, that checks 2593** to see if a database file was a URI that contained a specific query 2594** parameter, and if so obtains the value of the query parameter. 2595** 2596** The zFilename argument is the filename pointer passed into the xOpen() 2597** method of a VFS implementation. The zParam argument is the name of the 2598** query parameter we seek. This routine returns the value of the zParam 2599** parameter if it exists. If the parameter does not exist, this routine 2600** returns a NULL pointer. 2601** 2602** If the zFilename argument to this function is not a pointer that SQLite 2603** passed into the xOpen VFS method, then the behavior of this routine 2604** is undefined and probably undesirable. 2605*/ 2606SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 2607 2608 2609/* 2610** CAPI3REF: Error Codes And Messages 2611** 2612** ^The sqlite3_errcode() interface returns the numeric [result code] or 2613** [extended result code] for the most recent failed sqlite3_* API call 2614** associated with a [database connection]. If a prior API call failed 2615** but the most recent API call succeeded, the return value from 2616** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2617** interface is the same except that it always returns the 2618** [extended result code] even when extended result codes are 2619** disabled. 2620** 2621** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2622** text that describes the error, as either UTF-8 or UTF-16 respectively. 2623** ^(Memory to hold the error message string is managed internally. 2624** The application does not need to worry about freeing the result. 2625** However, the error string might be overwritten or deallocated by 2626** subsequent calls to other SQLite interface functions.)^ 2627** 2628** When the serialized [threading mode] is in use, it might be the 2629** case that a second error occurs on a separate thread in between 2630** the time of the first error and the call to these interfaces. 2631** When that happens, the second error will be reported since these 2632** interfaces always report the most recent result. To avoid 2633** this, each thread can obtain exclusive use of the [database connection] D 2634** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2635** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2636** all calls to the interfaces listed here are completed. 2637** 2638** If an interface fails with SQLITE_MISUSE, that means the interface 2639** was invoked incorrectly by the application. In that case, the 2640** error code and message may or may not be set. 2641*/ 2642SQLITE_API int sqlite3_errcode(sqlite3 *db); 2643SQLITE_API int sqlite3_extended_errcode(sqlite3 *db); 2644SQLITE_API const char *sqlite3_errmsg(sqlite3*); 2645SQLITE_API const void *sqlite3_errmsg16(sqlite3*); 2646 2647/* 2648** CAPI3REF: SQL Statement Object 2649** KEYWORDS: {prepared statement} {prepared statements} 2650** 2651** An instance of this object represents a single SQL statement. 2652** This object is variously known as a "prepared statement" or a 2653** "compiled SQL statement" or simply as a "statement". 2654** 2655** The life of a statement object goes something like this: 2656** 2657** <ol> 2658** <li> Create the object using [sqlite3_prepare_v2()] or a related 2659** function. 2660** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2661** interfaces. 2662** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2663** <li> Reset the statement using [sqlite3_reset()] then go back 2664** to step 2. Do this zero or more times. 2665** <li> Destroy the object using [sqlite3_finalize()]. 2666** </ol> 2667** 2668** Refer to documentation on individual methods above for additional 2669** information. 2670*/ 2671typedef struct sqlite3_stmt sqlite3_stmt; 2672 2673/* 2674** CAPI3REF: Run-time Limits 2675** 2676** ^(This interface allows the size of various constructs to be limited 2677** on a connection by connection basis. The first parameter is the 2678** [database connection] whose limit is to be set or queried. The 2679** second parameter is one of the [limit categories] that define a 2680** class of constructs to be size limited. The third parameter is the 2681** new limit for that construct.)^ 2682** 2683** ^If the new limit is a negative number, the limit is unchanged. 2684** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 2685** [limits | hard upper bound] 2686** set at compile-time by a C preprocessor macro called 2687** [limits | SQLITE_MAX_<i>NAME</i>]. 2688** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2689** ^Attempts to increase a limit above its hard upper bound are 2690** silently truncated to the hard upper bound. 2691** 2692** ^Regardless of whether or not the limit was changed, the 2693** [sqlite3_limit()] interface returns the prior value of the limit. 2694** ^Hence, to find the current value of a limit without changing it, 2695** simply invoke this interface with the third parameter set to -1. 2696** 2697** Run-time limits are intended for use in applications that manage 2698** both their own internal database and also databases that are controlled 2699** by untrusted external sources. An example application might be a 2700** web browser that has its own databases for storing history and 2701** separate databases controlled by JavaScript applications downloaded 2702** off the Internet. The internal databases can be given the 2703** large, default limits. Databases managed by external sources can 2704** be given much smaller limits designed to prevent a denial of service 2705** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2706** interface to further control untrusted SQL. The size of the database 2707** created by an untrusted script can be contained using the 2708** [max_page_count] [PRAGMA]. 2709** 2710** New run-time limit categories may be added in future releases. 2711*/ 2712SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal); 2713 2714/* 2715** CAPI3REF: Run-Time Limit Categories 2716** KEYWORDS: {limit category} {*limit categories} 2717** 2718** These constants define various performance limits 2719** that can be lowered at run-time using [sqlite3_limit()]. 2720** The synopsis of the meanings of the various limits is shown below. 2721** Additional information is available at [limits | Limits in SQLite]. 2722** 2723** <dl> 2724** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2725** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 2726** 2727** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2728** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2729** 2730** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2731** <dd>The maximum number of columns in a table definition or in the 2732** result set of a [SELECT] or the maximum number of columns in an index 2733** or in an ORDER BY or GROUP BY clause.</dd>)^ 2734** 2735** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2736** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2737** 2738** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2739** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2740** 2741** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2742** <dd>The maximum number of instructions in a virtual machine program 2743** used to implement an SQL statement. This limit is not currently 2744** enforced, though that might be added in some future release of 2745** SQLite.</dd>)^ 2746** 2747** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2748** <dd>The maximum number of arguments on a function.</dd>)^ 2749** 2750** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2751** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2752** 2753** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 2754** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2755** <dd>The maximum length of the pattern argument to the [LIKE] or 2756** [GLOB] operators.</dd>)^ 2757** 2758** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 2759** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2760** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 2761** 2762** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2763** <dd>The maximum depth of recursion for triggers.</dd>)^ 2764** </dl> 2765*/ 2766#define SQLITE_LIMIT_LENGTH 0 2767#define SQLITE_LIMIT_SQL_LENGTH 1 2768#define SQLITE_LIMIT_COLUMN 2 2769#define SQLITE_LIMIT_EXPR_DEPTH 3 2770#define SQLITE_LIMIT_COMPOUND_SELECT 4 2771#define SQLITE_LIMIT_VDBE_OP 5 2772#define SQLITE_LIMIT_FUNCTION_ARG 6 2773#define SQLITE_LIMIT_ATTACHED 7 2774#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2775#define SQLITE_LIMIT_VARIABLE_NUMBER 9 2776#define SQLITE_LIMIT_TRIGGER_DEPTH 10 2777 2778/* 2779** CAPI3REF: Compiling An SQL Statement 2780** KEYWORDS: {SQL statement compiler} 2781** 2782** To execute an SQL query, it must first be compiled into a byte-code 2783** program using one of these routines. 2784** 2785** The first argument, "db", is a [database connection] obtained from a 2786** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2787** [sqlite3_open16()]. The database connection must not have been closed. 2788** 2789** The second argument, "zSql", is the statement to be compiled, encoded 2790** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2791** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2792** use UTF-16. 2793** 2794** ^If the nByte argument is less than zero, then zSql is read up to the 2795** first zero terminator. ^If nByte is non-negative, then it is the maximum 2796** number of bytes read from zSql. ^When nByte is non-negative, the 2797** zSql string ends at either the first '\000' or '\u0000' character or 2798** the nByte-th byte, whichever comes first. If the caller knows 2799** that the supplied string is nul-terminated, then there is a small 2800** performance advantage to be gained by passing an nByte parameter that 2801** is equal to the number of bytes in the input string <i>including</i> 2802** the nul-terminator bytes. 2803** 2804** ^If pzTail is not NULL then *pzTail is made to point to the first byte 2805** past the end of the first SQL statement in zSql. These routines only 2806** compile the first statement in zSql, so *pzTail is left pointing to 2807** what remains uncompiled. 2808** 2809** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 2810** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 2811** to NULL. ^If the input text contains no SQL (if the input is an empty 2812** string or a comment) then *ppStmt is set to NULL. 2813** The calling procedure is responsible for deleting the compiled 2814** SQL statement using [sqlite3_finalize()] after it has finished with it. 2815** ppStmt may not be NULL. 2816** 2817** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 2818** otherwise an [error code] is returned. 2819** 2820** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2821** recommended for all new programs. The two older interfaces are retained 2822** for backwards compatibility, but their use is discouraged. 2823** ^In the "v2" interfaces, the prepared statement 2824** that is returned (the [sqlite3_stmt] object) contains a copy of the 2825** original SQL text. This causes the [sqlite3_step()] interface to 2826** behave differently in three ways: 2827** 2828** <ol> 2829** <li> 2830** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2831** always used to do, [sqlite3_step()] will automatically recompile the SQL 2832** statement and try to run it again. 2833** </li> 2834** 2835** <li> 2836** ^When an error occurs, [sqlite3_step()] will return one of the detailed 2837** [error codes] or [extended error codes]. ^The legacy behavior was that 2838** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2839** and the application would have to make a second call to [sqlite3_reset()] 2840** in order to find the underlying cause of the problem. With the "v2" prepare 2841** interfaces, the underlying reason for the error is returned immediately. 2842** </li> 2843** 2844** <li> 2845** ^If the specific value bound to [parameter | host parameter] in the 2846** WHERE clause might influence the choice of query plan for a statement, 2847** then the statement will be automatically recompiled, as if there had been 2848** a schema change, on the first [sqlite3_step()] call following any change 2849** to the [sqlite3_bind_text | bindings] of that [parameter]. 2850** ^The specific value of WHERE-clause [parameter] might influence the 2851** choice of query plan if the parameter is the left-hand side of a [LIKE] 2852** or [GLOB] operator or if the parameter is compared to an indexed column 2853** and the [SQLITE_ENABLE_STAT2] compile-time option is enabled. 2854** the 2855** </li> 2856** </ol> 2857*/ 2858SQLITE_API int sqlite3_prepare( 2859 sqlite3 *db, /* Database handle */ 2860 const char *zSql, /* SQL statement, UTF-8 encoded */ 2861 int nByte, /* Maximum length of zSql in bytes. */ 2862 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2863 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2864); 2865SQLITE_API int sqlite3_prepare_v2( 2866 sqlite3 *db, /* Database handle */ 2867 const char *zSql, /* SQL statement, UTF-8 encoded */ 2868 int nByte, /* Maximum length of zSql in bytes. */ 2869 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2870 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2871); 2872SQLITE_API int sqlite3_prepare16( 2873 sqlite3 *db, /* Database handle */ 2874 const void *zSql, /* SQL statement, UTF-16 encoded */ 2875 int nByte, /* Maximum length of zSql in bytes. */ 2876 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2877 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2878); 2879SQLITE_API int sqlite3_prepare16_v2( 2880 sqlite3 *db, /* Database handle */ 2881 const void *zSql, /* SQL statement, UTF-16 encoded */ 2882 int nByte, /* Maximum length of zSql in bytes. */ 2883 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2884 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2885); 2886 2887/* 2888** CAPI3REF: Retrieving Statement SQL 2889** 2890** ^This interface can be used to retrieve a saved copy of the original 2891** SQL text used to create a [prepared statement] if that statement was 2892** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2893*/ 2894SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt); 2895 2896/* 2897** CAPI3REF: Determine If An SQL Statement Writes The Database 2898** 2899** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 2900** and only if the [prepared statement] X makes no direct changes to 2901** the content of the database file. 2902** 2903** Note that [application-defined SQL functions] or 2904** [virtual tables] might change the database indirectly as a side effect. 2905** ^(For example, if an application defines a function "eval()" that 2906** calls [sqlite3_exec()], then the following SQL statement would 2907** change the database file through side-effects: 2908** 2909** <blockquote><pre> 2910** SELECT eval('DELETE FROM t1') FROM t2; 2911** </pre></blockquote> 2912** 2913** But because the [SELECT] statement does not change the database file 2914** directly, sqlite3_stmt_readonly() would still return true.)^ 2915** 2916** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 2917** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 2918** since the statements themselves do not actually modify the database but 2919** rather they control the timing of when other statements modify the 2920** database. ^The [ATTACH] and [DETACH] statements also cause 2921** sqlite3_stmt_readonly() to return true since, while those statements 2922** change the configuration of a database connection, they do not make 2923** changes to the content of the database files on disk. 2924*/ 2925SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 2926 2927/* 2928** CAPI3REF: Dynamically Typed Value Object 2929** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 2930** 2931** SQLite uses the sqlite3_value object to represent all values 2932** that can be stored in a database table. SQLite uses dynamic typing 2933** for the values it stores. ^Values stored in sqlite3_value objects 2934** can be integers, floating point values, strings, BLOBs, or NULL. 2935** 2936** An sqlite3_value object may be either "protected" or "unprotected". 2937** Some interfaces require a protected sqlite3_value. Other interfaces 2938** will accept either a protected or an unprotected sqlite3_value. 2939** Every interface that accepts sqlite3_value arguments specifies 2940** whether or not it requires a protected sqlite3_value. 2941** 2942** The terms "protected" and "unprotected" refer to whether or not 2943** a mutex is held. An internal mutex is held for a protected 2944** sqlite3_value object but no mutex is held for an unprotected 2945** sqlite3_value object. If SQLite is compiled to be single-threaded 2946** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 2947** or if SQLite is run in one of reduced mutex modes 2948** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 2949** then there is no distinction between protected and unprotected 2950** sqlite3_value objects and they can be used interchangeably. However, 2951** for maximum code portability it is recommended that applications 2952** still make the distinction between protected and unprotected 2953** sqlite3_value objects even when not strictly required. 2954** 2955** ^The sqlite3_value objects that are passed as parameters into the 2956** implementation of [application-defined SQL functions] are protected. 2957** ^The sqlite3_value object returned by 2958** [sqlite3_column_value()] is unprotected. 2959** Unprotected sqlite3_value objects may only be used with 2960** [sqlite3_result_value()] and [sqlite3_bind_value()]. 2961** The [sqlite3_value_blob | sqlite3_value_type()] family of 2962** interfaces require protected sqlite3_value objects. 2963*/ 2964typedef struct Mem sqlite3_value; 2965 2966/* 2967** CAPI3REF: SQL Function Context Object 2968** 2969** The context in which an SQL function executes is stored in an 2970** sqlite3_context object. ^A pointer to an sqlite3_context object 2971** is always first parameter to [application-defined SQL functions]. 2972** The application-defined SQL function implementation will pass this 2973** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 2974** [sqlite3_aggregate_context()], [sqlite3_user_data()], 2975** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 2976** and/or [sqlite3_set_auxdata()]. 2977*/ 2978typedef struct sqlite3_context sqlite3_context; 2979 2980/* 2981** CAPI3REF: Binding Values To Prepared Statements 2982** KEYWORDS: {host parameter} {host parameters} {host parameter name} 2983** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 2984** 2985** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 2986** literals may be replaced by a [parameter] that matches one of following 2987** templates: 2988** 2989** <ul> 2990** <li> ? 2991** <li> ?NNN 2992** <li> :VVV 2993** <li> @VVV 2994** <li> $VVV 2995** </ul> 2996** 2997** In the templates above, NNN represents an integer literal, 2998** and VVV represents an alphanumeric identifier.)^ ^The values of these 2999** parameters (also called "host parameter names" or "SQL parameters") 3000** can be set using the sqlite3_bind_*() routines defined here. 3001** 3002** ^The first argument to the sqlite3_bind_*() routines is always 3003** a pointer to the [sqlite3_stmt] object returned from 3004** [sqlite3_prepare_v2()] or its variants. 3005** 3006** ^The second argument is the index of the SQL parameter to be set. 3007** ^The leftmost SQL parameter has an index of 1. ^When the same named 3008** SQL parameter is used more than once, second and subsequent 3009** occurrences have the same index as the first occurrence. 3010** ^The index for named parameters can be looked up using the 3011** [sqlite3_bind_parameter_index()] API if desired. ^The index 3012** for "?NNN" parameters is the value of NNN. 3013** ^The NNN value must be between 1 and the [sqlite3_limit()] 3014** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3015** 3016** ^The third argument is the value to bind to the parameter. 3017** 3018** ^(In those routines that have a fourth argument, its value is the 3019** number of bytes in the parameter. To be clear: the value is the 3020** number of <u>bytes</u> in the value, not the number of characters.)^ 3021** ^If the fourth parameter is negative, the length of the string is 3022** the number of bytes up to the first zero terminator. 3023** 3024** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 3025** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 3026** string after SQLite has finished with it. ^The destructor is called 3027** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(), 3028** sqlite3_bind_text(), or sqlite3_bind_text16() fails. 3029** ^If the fifth argument is 3030** the special value [SQLITE_STATIC], then SQLite assumes that the 3031** information is in static, unmanaged space and does not need to be freed. 3032** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3033** SQLite makes its own private copy of the data immediately, before 3034** the sqlite3_bind_*() routine returns. 3035** 3036** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3037** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3038** (just an integer to hold its size) while it is being processed. 3039** Zeroblobs are intended to serve as placeholders for BLOBs whose 3040** content is later written using 3041** [sqlite3_blob_open | incremental BLOB I/O] routines. 3042** ^A negative value for the zeroblob results in a zero-length BLOB. 3043** 3044** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3045** for the [prepared statement] or with a prepared statement for which 3046** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3047** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3048** routine is passed a [prepared statement] that has been finalized, the 3049** result is undefined and probably harmful. 3050** 3051** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3052** ^Unbound parameters are interpreted as NULL. 3053** 3054** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3055** [error code] if anything goes wrong. 3056** ^[SQLITE_RANGE] is returned if the parameter 3057** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3058** 3059** See also: [sqlite3_bind_parameter_count()], 3060** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3061*/ 3062SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3063SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double); 3064SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int); 3065SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3066SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int); 3067SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 3068SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3069SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3070SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3071 3072/* 3073** CAPI3REF: Number Of SQL Parameters 3074** 3075** ^This routine can be used to find the number of [SQL parameters] 3076** in a [prepared statement]. SQL parameters are tokens of the 3077** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3078** placeholders for values that are [sqlite3_bind_blob | bound] 3079** to the parameters at a later time. 3080** 3081** ^(This routine actually returns the index of the largest (rightmost) 3082** parameter. For all forms except ?NNN, this will correspond to the 3083** number of unique parameters. If parameters of the ?NNN form are used, 3084** there may be gaps in the list.)^ 3085** 3086** See also: [sqlite3_bind_blob|sqlite3_bind()], 3087** [sqlite3_bind_parameter_name()], and 3088** [sqlite3_bind_parameter_index()]. 3089*/ 3090SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*); 3091 3092/* 3093** CAPI3REF: Name Of A Host Parameter 3094** 3095** ^The sqlite3_bind_parameter_name(P,N) interface returns 3096** the name of the N-th [SQL parameter] in the [prepared statement] P. 3097** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3098** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3099** respectively. 3100** In other words, the initial ":" or "$" or "@" or "?" 3101** is included as part of the name.)^ 3102** ^Parameters of the form "?" without a following integer have no name 3103** and are referred to as "nameless" or "anonymous parameters". 3104** 3105** ^The first host parameter has an index of 1, not 0. 3106** 3107** ^If the value N is out of range or if the N-th parameter is 3108** nameless, then NULL is returned. ^The returned string is 3109** always in UTF-8 encoding even if the named parameter was 3110** originally specified as UTF-16 in [sqlite3_prepare16()] or 3111** [sqlite3_prepare16_v2()]. 3112** 3113** See also: [sqlite3_bind_blob|sqlite3_bind()], 3114** [sqlite3_bind_parameter_count()], and 3115** [sqlite3_bind_parameter_index()]. 3116*/ 3117SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3118 3119/* 3120** CAPI3REF: Index Of A Parameter With A Given Name 3121** 3122** ^Return the index of an SQL parameter given its name. ^The 3123** index value returned is suitable for use as the second 3124** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3125** is returned if no matching parameter is found. ^The parameter 3126** name must be given in UTF-8 even if the original statement 3127** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3128** 3129** See also: [sqlite3_bind_blob|sqlite3_bind()], 3130** [sqlite3_bind_parameter_count()], and 3131** [sqlite3_bind_parameter_index()]. 3132*/ 3133SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3134 3135/* 3136** CAPI3REF: Reset All Bindings On A Prepared Statement 3137** 3138** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3139** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3140** ^Use this routine to reset all host parameters to NULL. 3141*/ 3142SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*); 3143 3144/* 3145** CAPI3REF: Number Of Columns In A Result Set 3146** 3147** ^Return the number of columns in the result set returned by the 3148** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3149** statement that does not return data (for example an [UPDATE]). 3150** 3151** See also: [sqlite3_data_count()] 3152*/ 3153SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt); 3154 3155/* 3156** CAPI3REF: Column Names In A Result Set 3157** 3158** ^These routines return the name assigned to a particular column 3159** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3160** interface returns a pointer to a zero-terminated UTF-8 string 3161** and sqlite3_column_name16() returns a pointer to a zero-terminated 3162** UTF-16 string. ^The first parameter is the [prepared statement] 3163** that implements the [SELECT] statement. ^The second parameter is the 3164** column number. ^The leftmost column is number 0. 3165** 3166** ^The returned string pointer is valid until either the [prepared statement] 3167** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3168** reprepared by the first call to [sqlite3_step()] for a particular run 3169** or until the next call to 3170** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3171** 3172** ^If sqlite3_malloc() fails during the processing of either routine 3173** (for example during a conversion from UTF-8 to UTF-16) then a 3174** NULL pointer is returned. 3175** 3176** ^The name of a result column is the value of the "AS" clause for 3177** that column, if there is an AS clause. If there is no AS clause 3178** then the name of the column is unspecified and may change from 3179** one release of SQLite to the next. 3180*/ 3181SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N); 3182SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3183 3184/* 3185** CAPI3REF: Source Of Data In A Query Result 3186** 3187** ^These routines provide a means to determine the database, table, and 3188** table column that is the origin of a particular result column in 3189** [SELECT] statement. 3190** ^The name of the database or table or column can be returned as 3191** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3192** the database name, the _table_ routines return the table name, and 3193** the origin_ routines return the column name. 3194** ^The returned string is valid until the [prepared statement] is destroyed 3195** using [sqlite3_finalize()] or until the statement is automatically 3196** reprepared by the first call to [sqlite3_step()] for a particular run 3197** or until the same information is requested 3198** again in a different encoding. 3199** 3200** ^The names returned are the original un-aliased names of the 3201** database, table, and column. 3202** 3203** ^The first argument to these interfaces is a [prepared statement]. 3204** ^These functions return information about the Nth result column returned by 3205** the statement, where N is the second function argument. 3206** ^The left-most column is column 0 for these routines. 3207** 3208** ^If the Nth column returned by the statement is an expression or 3209** subquery and is not a column value, then all of these functions return 3210** NULL. ^These routine might also return NULL if a memory allocation error 3211** occurs. ^Otherwise, they return the name of the attached database, table, 3212** or column that query result column was extracted from. 3213** 3214** ^As with all other SQLite APIs, those whose names end with "16" return 3215** UTF-16 encoded strings and the other functions return UTF-8. 3216** 3217** ^These APIs are only available if the library was compiled with the 3218** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3219** 3220** If two or more threads call one or more of these routines against the same 3221** prepared statement and column at the same time then the results are 3222** undefined. 3223** 3224** If two or more threads call one or more 3225** [sqlite3_column_database_name | column metadata interfaces] 3226** for the same [prepared statement] and result column 3227** at the same time then the results are undefined. 3228*/ 3229SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3230SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3231SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3232SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3233SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3234SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3235 3236/* 3237** CAPI3REF: Declared Datatype Of A Query Result 3238** 3239** ^(The first parameter is a [prepared statement]. 3240** If this statement is a [SELECT] statement and the Nth column of the 3241** returned result set of that [SELECT] is a table column (not an 3242** expression or subquery) then the declared type of the table 3243** column is returned.)^ ^If the Nth column of the result set is an 3244** expression or subquery, then a NULL pointer is returned. 3245** ^The returned string is always UTF-8 encoded. 3246** 3247** ^(For example, given the database schema: 3248** 3249** CREATE TABLE t1(c1 VARIANT); 3250** 3251** and the following statement to be compiled: 3252** 3253** SELECT c1 + 1, c1 FROM t1; 3254** 3255** this routine would return the string "VARIANT" for the second result 3256** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3257** 3258** ^SQLite uses dynamic run-time typing. ^So just because a column 3259** is declared to contain a particular type does not mean that the 3260** data stored in that column is of the declared type. SQLite is 3261** strongly typed, but the typing is dynamic not static. ^Type 3262** is associated with individual values, not with the containers 3263** used to hold those values. 3264*/ 3265SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3266SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3267 3268/* 3269** CAPI3REF: Evaluate An SQL Statement 3270** 3271** After a [prepared statement] has been prepared using either 3272** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3273** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3274** must be called one or more times to evaluate the statement. 3275** 3276** The details of the behavior of the sqlite3_step() interface depend 3277** on whether the statement was prepared using the newer "v2" interface 3278** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3279** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3280** new "v2" interface is recommended for new applications but the legacy 3281** interface will continue to be supported. 3282** 3283** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3284** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3285** ^With the "v2" interface, any of the other [result codes] or 3286** [extended result codes] might be returned as well. 3287** 3288** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3289** database locks it needs to do its job. ^If the statement is a [COMMIT] 3290** or occurs outside of an explicit transaction, then you can retry the 3291** statement. If the statement is not a [COMMIT] and occurs within an 3292** explicit transaction then you should rollback the transaction before 3293** continuing. 3294** 3295** ^[SQLITE_DONE] means that the statement has finished executing 3296** successfully. sqlite3_step() should not be called again on this virtual 3297** machine without first calling [sqlite3_reset()] to reset the virtual 3298** machine back to its initial state. 3299** 3300** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3301** is returned each time a new row of data is ready for processing by the 3302** caller. The values may be accessed using the [column access functions]. 3303** sqlite3_step() is called again to retrieve the next row of data. 3304** 3305** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3306** violation) has occurred. sqlite3_step() should not be called again on 3307** the VM. More information may be found by calling [sqlite3_errmsg()]. 3308** ^With the legacy interface, a more specific error code (for example, 3309** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3310** can be obtained by calling [sqlite3_reset()] on the 3311** [prepared statement]. ^In the "v2" interface, 3312** the more specific error code is returned directly by sqlite3_step(). 3313** 3314** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3315** Perhaps it was called on a [prepared statement] that has 3316** already been [sqlite3_finalize | finalized] or on one that had 3317** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3318** be the case that the same database connection is being used by two or 3319** more threads at the same moment in time. 3320** 3321** For all versions of SQLite up to and including 3.6.23.1, a call to 3322** [sqlite3_reset()] was required after sqlite3_step() returned anything 3323** other than [SQLITE_ROW] before any subsequent invocation of 3324** sqlite3_step(). Failure to reset the prepared statement using 3325** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3326** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3327** calling [sqlite3_reset()] automatically in this circumstance rather 3328** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3329** break because any application that ever receives an SQLITE_MISUSE error 3330** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3331** can be used to restore the legacy behavior. 3332** 3333** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3334** API always returns a generic error code, [SQLITE_ERROR], following any 3335** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3336** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3337** specific [error codes] that better describes the error. 3338** We admit that this is a goofy design. The problem has been fixed 3339** with the "v2" interface. If you prepare all of your SQL statements 3340** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3341** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3342** then the more specific [error codes] are returned directly 3343** by sqlite3_step(). The use of the "v2" interface is recommended. 3344*/ 3345SQLITE_API int sqlite3_step(sqlite3_stmt*); 3346 3347/* 3348** CAPI3REF: Number of columns in a result set 3349** 3350** ^The sqlite3_data_count(P) interface returns the number of columns in the 3351** current row of the result set of [prepared statement] P. 3352** ^If prepared statement P does not have results ready to return 3353** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3354** interfaces) then sqlite3_data_count(P) returns 0. 3355** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3356** 3357** See also: [sqlite3_column_count()] 3358*/ 3359SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt); 3360 3361/* 3362** CAPI3REF: Fundamental Datatypes 3363** KEYWORDS: SQLITE_TEXT 3364** 3365** ^(Every value in SQLite has one of five fundamental datatypes: 3366** 3367** <ul> 3368** <li> 64-bit signed integer 3369** <li> 64-bit IEEE floating point number 3370** <li> string 3371** <li> BLOB 3372** <li> NULL 3373** </ul>)^ 3374** 3375** These constants are codes for each of those types. 3376** 3377** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3378** for a completely different meaning. Software that links against both 3379** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3380** SQLITE_TEXT. 3381*/ 3382#define SQLITE_INTEGER 1 3383#define SQLITE_FLOAT 2 3384#define SQLITE_BLOB 4 3385#define SQLITE_NULL 5 3386#ifdef SQLITE_TEXT 3387# undef SQLITE_TEXT 3388#else 3389# define SQLITE_TEXT 3 3390#endif 3391#define SQLITE3_TEXT 3 3392 3393/* 3394** CAPI3REF: Result Values From A Query 3395** KEYWORDS: {column access functions} 3396** 3397** These routines form the "result set" interface. 3398** 3399** ^These routines return information about a single column of the current 3400** result row of a query. ^In every case the first argument is a pointer 3401** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3402** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3403** and the second argument is the index of the column for which information 3404** should be returned. ^The leftmost column of the result set has the index 0. 3405** ^The number of columns in the result can be determined using 3406** [sqlite3_column_count()]. 3407** 3408** If the SQL statement does not currently point to a valid row, or if the 3409** column index is out of range, the result is undefined. 3410** These routines may only be called when the most recent call to 3411** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3412** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3413** If any of these routines are called after [sqlite3_reset()] or 3414** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3415** something other than [SQLITE_ROW], the results are undefined. 3416** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3417** are called from a different thread while any of these routines 3418** are pending, then the results are undefined. 3419** 3420** ^The sqlite3_column_type() routine returns the 3421** [SQLITE_INTEGER | datatype code] for the initial data type 3422** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3423** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3424** returned by sqlite3_column_type() is only meaningful if no type 3425** conversions have occurred as described below. After a type conversion, 3426** the value returned by sqlite3_column_type() is undefined. Future 3427** versions of SQLite may change the behavior of sqlite3_column_type() 3428** following a type conversion. 3429** 3430** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3431** routine returns the number of bytes in that BLOB or string. 3432** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3433** the string to UTF-8 and then returns the number of bytes. 3434** ^If the result is a numeric value then sqlite3_column_bytes() uses 3435** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3436** the number of bytes in that string. 3437** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3438** 3439** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3440** routine returns the number of bytes in that BLOB or string. 3441** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3442** the string to UTF-16 and then returns the number of bytes. 3443** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3444** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3445** the number of bytes in that string. 3446** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3447** 3448** ^The values returned by [sqlite3_column_bytes()] and 3449** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3450** of the string. ^For clarity: the values returned by 3451** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3452** bytes in the string, not the number of characters. 3453** 3454** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3455** even empty strings, are always zero terminated. ^The return 3456** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3457** 3458** ^The object returned by [sqlite3_column_value()] is an 3459** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3460** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3461** If the [unprotected sqlite3_value] object returned by 3462** [sqlite3_column_value()] is used in any other way, including calls 3463** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3464** or [sqlite3_value_bytes()], then the behavior is undefined. 3465** 3466** These routines attempt to convert the value where appropriate. ^For 3467** example, if the internal representation is FLOAT and a text result 3468** is requested, [sqlite3_snprintf()] is used internally to perform the 3469** conversion automatically. ^(The following table details the conversions 3470** that are applied: 3471** 3472** <blockquote> 3473** <table border="1"> 3474** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3475** 3476** <tr><td> NULL <td> INTEGER <td> Result is 0 3477** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3478** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3479** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3480** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3481** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3482** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3483** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3484** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3485** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3486** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3487** <tr><td> TEXT <td> FLOAT <td> Use atof() 3488** <tr><td> TEXT <td> BLOB <td> No change 3489** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3490** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3491** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3492** </table> 3493** </blockquote>)^ 3494** 3495** The table above makes reference to standard C library functions atoi() 3496** and atof(). SQLite does not really use these functions. It has its 3497** own equivalent internal routines. The atoi() and atof() names are 3498** used in the table for brevity and because they are familiar to most 3499** C programmers. 3500** 3501** Note that when type conversions occur, pointers returned by prior 3502** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3503** sqlite3_column_text16() may be invalidated. 3504** Type conversions and pointer invalidations might occur 3505** in the following cases: 3506** 3507** <ul> 3508** <li> The initial content is a BLOB and sqlite3_column_text() or 3509** sqlite3_column_text16() is called. A zero-terminator might 3510** need to be added to the string.</li> 3511** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3512** sqlite3_column_text16() is called. The content must be converted 3513** to UTF-16.</li> 3514** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3515** sqlite3_column_text() is called. The content must be converted 3516** to UTF-8.</li> 3517** </ul> 3518** 3519** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3520** not invalidate a prior pointer, though of course the content of the buffer 3521** that the prior pointer references will have been modified. Other kinds 3522** of conversion are done in place when it is possible, but sometimes they 3523** are not possible and in those cases prior pointers are invalidated. 3524** 3525** The safest and easiest to remember policy is to invoke these routines 3526** in one of the following ways: 3527** 3528** <ul> 3529** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3530** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3531** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3532** </ul> 3533** 3534** In other words, you should call sqlite3_column_text(), 3535** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3536** into the desired format, then invoke sqlite3_column_bytes() or 3537** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3538** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3539** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3540** with calls to sqlite3_column_bytes(). 3541** 3542** ^The pointers returned are valid until a type conversion occurs as 3543** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3544** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3545** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3546** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3547** [sqlite3_free()]. 3548** 3549** ^(If a memory allocation error occurs during the evaluation of any 3550** of these routines, a default value is returned. The default value 3551** is either the integer 0, the floating point number 0.0, or a NULL 3552** pointer. Subsequent calls to [sqlite3_errcode()] will return 3553** [SQLITE_NOMEM].)^ 3554*/ 3555SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3556SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3557SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3558SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol); 3559SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol); 3560SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3561SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3562SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3563SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol); 3564SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3565 3566/* 3567** CAPI3REF: Destroy A Prepared Statement Object 3568** 3569** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3570** ^If the most recent evaluation of the statement encountered no errors 3571** or if the statement is never been evaluated, then sqlite3_finalize() returns 3572** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 3573** sqlite3_finalize(S) returns the appropriate [error code] or 3574** [extended error code]. 3575** 3576** ^The sqlite3_finalize(S) routine can be called at any point during 3577** the life cycle of [prepared statement] S: 3578** before statement S is ever evaluated, after 3579** one or more calls to [sqlite3_reset()], or after any call 3580** to [sqlite3_step()] regardless of whether or not the statement has 3581** completed execution. 3582** 3583** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 3584** 3585** The application must finalize every [prepared statement] in order to avoid 3586** resource leaks. It is a grievous error for the application to try to use 3587** a prepared statement after it has been finalized. Any use of a prepared 3588** statement after it has been finalized can result in undefined and 3589** undesirable behavior such as segfaults and heap corruption. 3590*/ 3591SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt); 3592 3593/* 3594** CAPI3REF: Reset A Prepared Statement Object 3595** 3596** The sqlite3_reset() function is called to reset a [prepared statement] 3597** object back to its initial state, ready to be re-executed. 3598** ^Any SQL statement variables that had values bound to them using 3599** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3600** Use [sqlite3_clear_bindings()] to reset the bindings. 3601** 3602** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3603** back to the beginning of its program. 3604** 3605** ^If the most recent call to [sqlite3_step(S)] for the 3606** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3607** or if [sqlite3_step(S)] has never before been called on S, 3608** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3609** 3610** ^If the most recent call to [sqlite3_step(S)] for the 3611** [prepared statement] S indicated an error, then 3612** [sqlite3_reset(S)] returns an appropriate [error code]. 3613** 3614** ^The [sqlite3_reset(S)] interface does not change the values 3615** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3616*/ 3617SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt); 3618 3619/* 3620** CAPI3REF: Create Or Redefine SQL Functions 3621** KEYWORDS: {function creation routines} 3622** KEYWORDS: {application-defined SQL function} 3623** KEYWORDS: {application-defined SQL functions} 3624** 3625** ^These functions (collectively known as "function creation routines") 3626** are used to add SQL functions or aggregates or to redefine the behavior 3627** of existing SQL functions or aggregates. The only differences between 3628** these routines are the text encoding expected for 3629** the second parameter (the name of the function being created) 3630** and the presence or absence of a destructor callback for 3631** the application data pointer. 3632** 3633** ^The first parameter is the [database connection] to which the SQL 3634** function is to be added. ^If an application uses more than one database 3635** connection then application-defined SQL functions must be added 3636** to each database connection separately. 3637** 3638** ^The second parameter is the name of the SQL function to be created or 3639** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 3640** representation, exclusive of the zero-terminator. ^Note that the name 3641** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 3642** ^Any attempt to create a function with a longer name 3643** will result in [SQLITE_MISUSE] being returned. 3644** 3645** ^The third parameter (nArg) 3646** is the number of arguments that the SQL function or 3647** aggregate takes. ^If this parameter is -1, then the SQL function or 3648** aggregate may take any number of arguments between 0 and the limit 3649** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3650** parameter is less than -1 or greater than 127 then the behavior is 3651** undefined. 3652** 3653** ^The fourth parameter, eTextRep, specifies what 3654** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3655** its parameters. Every SQL function implementation must be able to work 3656** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3657** more efficient with one encoding than another. ^An application may 3658** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3659** times with the same function but with different values of eTextRep. 3660** ^When multiple implementations of the same function are available, SQLite 3661** will pick the one that involves the least amount of data conversion. 3662** If there is only a single implementation which does not care what text 3663** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3664** 3665** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3666** function can gain access to this pointer using [sqlite3_user_data()].)^ 3667** 3668** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 3669** pointers to C-language functions that implement the SQL function or 3670** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3671** callback only; NULL pointers must be passed as the xStep and xFinal 3672** parameters. ^An aggregate SQL function requires an implementation of xStep 3673** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 3674** SQL function or aggregate, pass NULL pointers for all three function 3675** callbacks. 3676** 3677** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 3678** then it is destructor for the application data pointer. 3679** The destructor is invoked when the function is deleted, either by being 3680** overloaded or when the database connection closes.)^ 3681** ^The destructor is also invoked if the call to 3682** sqlite3_create_function_v2() fails. 3683** ^When the destructor callback of the tenth parameter is invoked, it 3684** is passed a single argument which is a copy of the application data 3685** pointer which was the fifth parameter to sqlite3_create_function_v2(). 3686** 3687** ^It is permitted to register multiple implementations of the same 3688** functions with the same name but with either differing numbers of 3689** arguments or differing preferred text encodings. ^SQLite will use 3690** the implementation that most closely matches the way in which the 3691** SQL function is used. ^A function implementation with a non-negative 3692** nArg parameter is a better match than a function implementation with 3693** a negative nArg. ^A function where the preferred text encoding 3694** matches the database encoding is a better 3695** match than a function where the encoding is different. 3696** ^A function where the encoding difference is between UTF16le and UTF16be 3697** is a closer match than a function where the encoding difference is 3698** between UTF8 and UTF16. 3699** 3700** ^Built-in functions may be overloaded by new application-defined functions. 3701** 3702** ^An application-defined function is permitted to call other 3703** SQLite interfaces. However, such calls must not 3704** close the database connection nor finalize or reset the prepared 3705** statement in which the function is running. 3706*/ 3707SQLITE_API int sqlite3_create_function( 3708 sqlite3 *db, 3709 const char *zFunctionName, 3710 int nArg, 3711 int eTextRep, 3712 void *pApp, 3713 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3714 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3715 void (*xFinal)(sqlite3_context*) 3716); 3717SQLITE_API int sqlite3_create_function16( 3718 sqlite3 *db, 3719 const void *zFunctionName, 3720 int nArg, 3721 int eTextRep, 3722 void *pApp, 3723 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3724 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3725 void (*xFinal)(sqlite3_context*) 3726); 3727SQLITE_API int sqlite3_create_function_v2( 3728 sqlite3 *db, 3729 const char *zFunctionName, 3730 int nArg, 3731 int eTextRep, 3732 void *pApp, 3733 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3734 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3735 void (*xFinal)(sqlite3_context*), 3736 void(*xDestroy)(void*) 3737); 3738 3739/* 3740** CAPI3REF: Text Encodings 3741** 3742** These constant define integer codes that represent the various 3743** text encodings supported by SQLite. 3744*/ 3745#define SQLITE_UTF8 1 3746#define SQLITE_UTF16LE 2 3747#define SQLITE_UTF16BE 3 3748#define SQLITE_UTF16 4 /* Use native byte order */ 3749#define SQLITE_ANY 5 /* sqlite3_create_function only */ 3750#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3751 3752/* 3753** CAPI3REF: Deprecated Functions 3754** DEPRECATED 3755** 3756** These functions are [deprecated]. In order to maintain 3757** backwards compatibility with older code, these functions continue 3758** to be supported. However, new applications should avoid 3759** the use of these functions. To help encourage people to avoid 3760** using these functions, we are not going to tell you what they do. 3761*/ 3762#ifndef SQLITE_OMIT_DEPRECATED 3763SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3764SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3765SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3766SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void); 3767SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3768SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3769#endif 3770 3771/* 3772** CAPI3REF: Obtaining SQL Function Parameter Values 3773** 3774** The C-language implementation of SQL functions and aggregates uses 3775** this set of interface routines to access the parameter values on 3776** the function or aggregate. 3777** 3778** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3779** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3780** define callbacks that implement the SQL functions and aggregates. 3781** The 3rd parameter to these callbacks is an array of pointers to 3782** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3783** each parameter to the SQL function. These routines are used to 3784** extract values from the [sqlite3_value] objects. 3785** 3786** These routines work only with [protected sqlite3_value] objects. 3787** Any attempt to use these routines on an [unprotected sqlite3_value] 3788** object results in undefined behavior. 3789** 3790** ^These routines work just like the corresponding [column access functions] 3791** except that these routines take a single [protected sqlite3_value] object 3792** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3793** 3794** ^The sqlite3_value_text16() interface extracts a UTF-16 string 3795** in the native byte-order of the host machine. ^The 3796** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3797** extract UTF-16 strings as big-endian and little-endian respectively. 3798** 3799** ^(The sqlite3_value_numeric_type() interface attempts to apply 3800** numeric affinity to the value. This means that an attempt is 3801** made to convert the value to an integer or floating point. If 3802** such a conversion is possible without loss of information (in other 3803** words, if the value is a string that looks like a number) 3804** then the conversion is performed. Otherwise no conversion occurs. 3805** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 3806** 3807** Please pay particular attention to the fact that the pointer returned 3808** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3809** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3810** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3811** or [sqlite3_value_text16()]. 3812** 3813** These routines must be called from the same thread as 3814** the SQL function that supplied the [sqlite3_value*] parameters. 3815*/ 3816SQLITE_API const void *sqlite3_value_blob(sqlite3_value*); 3817SQLITE_API int sqlite3_value_bytes(sqlite3_value*); 3818SQLITE_API int sqlite3_value_bytes16(sqlite3_value*); 3819SQLITE_API double sqlite3_value_double(sqlite3_value*); 3820SQLITE_API int sqlite3_value_int(sqlite3_value*); 3821SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3822SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*); 3823SQLITE_API const void *sqlite3_value_text16(sqlite3_value*); 3824SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*); 3825SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*); 3826SQLITE_API int sqlite3_value_type(sqlite3_value*); 3827SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*); 3828 3829/* 3830** CAPI3REF: Obtain Aggregate Function Context 3831** 3832** Implementations of aggregate SQL functions use this 3833** routine to allocate memory for storing their state. 3834** 3835** ^The first time the sqlite3_aggregate_context(C,N) routine is called 3836** for a particular aggregate function, SQLite 3837** allocates N of memory, zeroes out that memory, and returns a pointer 3838** to the new memory. ^On second and subsequent calls to 3839** sqlite3_aggregate_context() for the same aggregate function instance, 3840** the same buffer is returned. Sqlite3_aggregate_context() is normally 3841** called once for each invocation of the xStep callback and then one 3842** last time when the xFinal callback is invoked. ^(When no rows match 3843** an aggregate query, the xStep() callback of the aggregate function 3844** implementation is never called and xFinal() is called exactly once. 3845** In those cases, sqlite3_aggregate_context() might be called for the 3846** first time from within xFinal().)^ 3847** 3848** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is 3849** less than or equal to zero or if a memory allocate error occurs. 3850** 3851** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 3852** determined by the N parameter on first successful call. Changing the 3853** value of N in subsequent call to sqlite3_aggregate_context() within 3854** the same aggregate function instance will not resize the memory 3855** allocation.)^ 3856** 3857** ^SQLite automatically frees the memory allocated by 3858** sqlite3_aggregate_context() when the aggregate query concludes. 3859** 3860** The first parameter must be a copy of the 3861** [sqlite3_context | SQL function context] that is the first parameter 3862** to the xStep or xFinal callback routine that implements the aggregate 3863** function. 3864** 3865** This routine must be called from the same thread in which 3866** the aggregate SQL function is running. 3867*/ 3868SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 3869 3870/* 3871** CAPI3REF: User Data For Functions 3872** 3873** ^The sqlite3_user_data() interface returns a copy of 3874** the pointer that was the pUserData parameter (the 5th parameter) 3875** of the [sqlite3_create_function()] 3876** and [sqlite3_create_function16()] routines that originally 3877** registered the application defined function. 3878** 3879** This routine must be called from the same thread in which 3880** the application-defined function is running. 3881*/ 3882SQLITE_API void *sqlite3_user_data(sqlite3_context*); 3883 3884/* 3885** CAPI3REF: Database Connection For Functions 3886** 3887** ^The sqlite3_context_db_handle() interface returns a copy of 3888** the pointer to the [database connection] (the 1st parameter) 3889** of the [sqlite3_create_function()] 3890** and [sqlite3_create_function16()] routines that originally 3891** registered the application defined function. 3892*/ 3893SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 3894 3895/* 3896** CAPI3REF: Function Auxiliary Data 3897** 3898** The following two functions may be used by scalar SQL functions to 3899** associate metadata with argument values. If the same value is passed to 3900** multiple invocations of the same SQL function during query execution, under 3901** some circumstances the associated metadata may be preserved. This may 3902** be used, for example, to add a regular-expression matching scalar 3903** function. The compiled version of the regular expression is stored as 3904** metadata associated with the SQL value passed as the regular expression 3905** pattern. The compiled regular expression can be reused on multiple 3906** invocations of the same function so that the original pattern string 3907** does not need to be recompiled on each invocation. 3908** 3909** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 3910** associated by the sqlite3_set_auxdata() function with the Nth argument 3911** value to the application-defined function. ^If no metadata has been ever 3912** been set for the Nth argument of the function, or if the corresponding 3913** function parameter has changed since the meta-data was set, 3914** then sqlite3_get_auxdata() returns a NULL pointer. 3915** 3916** ^The sqlite3_set_auxdata() interface saves the metadata 3917** pointed to by its 3rd parameter as the metadata for the N-th 3918** argument of the application-defined function. Subsequent 3919** calls to sqlite3_get_auxdata() might return this data, if it has 3920** not been destroyed. 3921** ^If it is not NULL, SQLite will invoke the destructor 3922** function given by the 4th parameter to sqlite3_set_auxdata() on 3923** the metadata when the corresponding function parameter changes 3924** or when the SQL statement completes, whichever comes first. 3925** 3926** SQLite is free to call the destructor and drop metadata on any 3927** parameter of any function at any time. ^The only guarantee is that 3928** the destructor will be called before the metadata is dropped. 3929** 3930** ^(In practice, metadata is preserved between function calls for 3931** expressions that are constant at compile time. This includes literal 3932** values and [parameters].)^ 3933** 3934** These routines must be called from the same thread in which 3935** the SQL function is running. 3936*/ 3937SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N); 3938SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 3939 3940 3941/* 3942** CAPI3REF: Constants Defining Special Destructor Behavior 3943** 3944** These are special values for the destructor that is passed in as the 3945** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 3946** argument is SQLITE_STATIC, it means that the content pointer is constant 3947** and will never change. It does not need to be destroyed. ^The 3948** SQLITE_TRANSIENT value means that the content will likely change in 3949** the near future and that SQLite should make its own private copy of 3950** the content before returning. 3951** 3952** The typedef is necessary to work around problems in certain 3953** C++ compilers. See ticket #2191. 3954*/ 3955typedef void (*sqlite3_destructor_type)(void*); 3956#define SQLITE_STATIC ((sqlite3_destructor_type)0) 3957#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 3958 3959/* 3960** CAPI3REF: Setting The Result Of An SQL Function 3961** 3962** These routines are used by the xFunc or xFinal callbacks that 3963** implement SQL functions and aggregates. See 3964** [sqlite3_create_function()] and [sqlite3_create_function16()] 3965** for additional information. 3966** 3967** These functions work very much like the [parameter binding] family of 3968** functions used to bind values to host parameters in prepared statements. 3969** Refer to the [SQL parameter] documentation for additional information. 3970** 3971** ^The sqlite3_result_blob() interface sets the result from 3972** an application-defined function to be the BLOB whose content is pointed 3973** to by the second parameter and which is N bytes long where N is the 3974** third parameter. 3975** 3976** ^The sqlite3_result_zeroblob() interfaces set the result of 3977** the application-defined function to be a BLOB containing all zero 3978** bytes and N bytes in size, where N is the value of the 2nd parameter. 3979** 3980** ^The sqlite3_result_double() interface sets the result from 3981** an application-defined function to be a floating point value specified 3982** by its 2nd argument. 3983** 3984** ^The sqlite3_result_error() and sqlite3_result_error16() functions 3985** cause the implemented SQL function to throw an exception. 3986** ^SQLite uses the string pointed to by the 3987** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 3988** as the text of an error message. ^SQLite interprets the error 3989** message string from sqlite3_result_error() as UTF-8. ^SQLite 3990** interprets the string from sqlite3_result_error16() as UTF-16 in native 3991** byte order. ^If the third parameter to sqlite3_result_error() 3992** or sqlite3_result_error16() is negative then SQLite takes as the error 3993** message all text up through the first zero character. 3994** ^If the third parameter to sqlite3_result_error() or 3995** sqlite3_result_error16() is non-negative then SQLite takes that many 3996** bytes (not characters) from the 2nd parameter as the error message. 3997** ^The sqlite3_result_error() and sqlite3_result_error16() 3998** routines make a private copy of the error message text before 3999** they return. Hence, the calling function can deallocate or 4000** modify the text after they return without harm. 4001** ^The sqlite3_result_error_code() function changes the error code 4002** returned by SQLite as a result of an error in a function. ^By default, 4003** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4004** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4005** 4006** ^The sqlite3_result_toobig() interface causes SQLite to throw an error 4007** indicating that a string or BLOB is too long to represent. 4008** 4009** ^The sqlite3_result_nomem() interface causes SQLite to throw an error 4010** indicating that a memory allocation failed. 4011** 4012** ^The sqlite3_result_int() interface sets the return value 4013** of the application-defined function to be the 32-bit signed integer 4014** value given in the 2nd argument. 4015** ^The sqlite3_result_int64() interface sets the return value 4016** of the application-defined function to be the 64-bit signed integer 4017** value given in the 2nd argument. 4018** 4019** ^The sqlite3_result_null() interface sets the return value 4020** of the application-defined function to be NULL. 4021** 4022** ^The sqlite3_result_text(), sqlite3_result_text16(), 4023** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4024** set the return value of the application-defined function to be 4025** a text string which is represented as UTF-8, UTF-16 native byte order, 4026** UTF-16 little endian, or UTF-16 big endian, respectively. 4027** ^SQLite takes the text result from the application from 4028** the 2nd parameter of the sqlite3_result_text* interfaces. 4029** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4030** is negative, then SQLite takes result text from the 2nd parameter 4031** through the first zero character. 4032** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4033** is non-negative, then as many bytes (not characters) of the text 4034** pointed to by the 2nd parameter are taken as the application-defined 4035** function result. 4036** ^If the 4th parameter to the sqlite3_result_text* interfaces 4037** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4038** function as the destructor on the text or BLOB result when it has 4039** finished using that result. 4040** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4041** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4042** assumes that the text or BLOB result is in constant space and does not 4043** copy the content of the parameter nor call a destructor on the content 4044** when it has finished using that result. 4045** ^If the 4th parameter to the sqlite3_result_text* interfaces 4046** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4047** then SQLite makes a copy of the result into space obtained from 4048** from [sqlite3_malloc()] before it returns. 4049** 4050** ^The sqlite3_result_value() interface sets the result of 4051** the application-defined function to be a copy the 4052** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4053** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4054** so that the [sqlite3_value] specified in the parameter may change or 4055** be deallocated after sqlite3_result_value() returns without harm. 4056** ^A [protected sqlite3_value] object may always be used where an 4057** [unprotected sqlite3_value] object is required, so either 4058** kind of [sqlite3_value] object can be used with this interface. 4059** 4060** If these routines are called from within the different thread 4061** than the one containing the application-defined function that received 4062** the [sqlite3_context] pointer, the results are undefined. 4063*/ 4064SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4065SQLITE_API void sqlite3_result_double(sqlite3_context*, double); 4066SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int); 4067SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int); 4068SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*); 4069SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*); 4070SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int); 4071SQLITE_API void sqlite3_result_int(sqlite3_context*, int); 4072SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4073SQLITE_API void sqlite3_result_null(sqlite3_context*); 4074SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4075SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4076SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4077SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4078SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4079SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n); 4080 4081/* 4082** CAPI3REF: Define New Collating Sequences 4083** 4084** ^These functions add, remove, or modify a [collation] associated 4085** with the [database connection] specified as the first argument. 4086** 4087** ^The name of the collation is a UTF-8 string 4088** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4089** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4090** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4091** considered to be the same name. 4092** 4093** ^(The third argument (eTextRep) must be one of the constants: 4094** <ul> 4095** <li> [SQLITE_UTF8], 4096** <li> [SQLITE_UTF16LE], 4097** <li> [SQLITE_UTF16BE], 4098** <li> [SQLITE_UTF16], or 4099** <li> [SQLITE_UTF16_ALIGNED]. 4100** </ul>)^ 4101** ^The eTextRep argument determines the encoding of strings passed 4102** to the collating function callback, xCallback. 4103** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4104** force strings to be UTF16 with native byte order. 4105** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4106** on an even byte address. 4107** 4108** ^The fourth argument, pArg, is an application data pointer that is passed 4109** through as the first argument to the collating function callback. 4110** 4111** ^The fifth argument, xCallback, is a pointer to the collating function. 4112** ^Multiple collating functions can be registered using the same name but 4113** with different eTextRep parameters and SQLite will use whichever 4114** function requires the least amount of data transformation. 4115** ^If the xCallback argument is NULL then the collating function is 4116** deleted. ^When all collating functions having the same name are deleted, 4117** that collation is no longer usable. 4118** 4119** ^The collating function callback is invoked with a copy of the pArg 4120** application data pointer and with two strings in the encoding specified 4121** by the eTextRep argument. The collating function must return an 4122** integer that is negative, zero, or positive 4123** if the first string is less than, equal to, or greater than the second, 4124** respectively. A collating function must always return the same answer 4125** given the same inputs. If two or more collating functions are registered 4126** to the same collation name (using different eTextRep values) then all 4127** must give an equivalent answer when invoked with equivalent strings. 4128** The collating function must obey the following properties for all 4129** strings A, B, and C: 4130** 4131** <ol> 4132** <li> If A==B then B==A. 4133** <li> If A==B and B==C then A==C. 4134** <li> If A<B THEN B>A. 4135** <li> If A<B and B<C then A<C. 4136** </ol> 4137** 4138** If a collating function fails any of the above constraints and that 4139** collating function is registered and used, then the behavior of SQLite 4140** is undefined. 4141** 4142** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4143** with the addition that the xDestroy callback is invoked on pArg when 4144** the collating function is deleted. 4145** ^Collating functions are deleted when they are overridden by later 4146** calls to the collation creation functions or when the 4147** [database connection] is closed using [sqlite3_close()]. 4148** 4149** ^The xDestroy callback is <u>not</u> called if the 4150** sqlite3_create_collation_v2() function fails. Applications that invoke 4151** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4152** check the return code and dispose of the application data pointer 4153** themselves rather than expecting SQLite to deal with it for them. 4154** This is different from every other SQLite interface. The inconsistency 4155** is unfortunate but cannot be changed without breaking backwards 4156** compatibility. 4157** 4158** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4159*/ 4160SQLITE_API int sqlite3_create_collation( 4161 sqlite3*, 4162 const char *zName, 4163 int eTextRep, 4164 void *pArg, 4165 int(*xCompare)(void*,int,const void*,int,const void*) 4166); 4167SQLITE_API int sqlite3_create_collation_v2( 4168 sqlite3*, 4169 const char *zName, 4170 int eTextRep, 4171 void *pArg, 4172 int(*xCompare)(void*,int,const void*,int,const void*), 4173 void(*xDestroy)(void*) 4174); 4175SQLITE_API int sqlite3_create_collation16( 4176 sqlite3*, 4177 const void *zName, 4178 int eTextRep, 4179 void *pArg, 4180 int(*xCompare)(void*,int,const void*,int,const void*) 4181); 4182 4183/* 4184** CAPI3REF: Collation Needed Callbacks 4185** 4186** ^To avoid having to register all collation sequences before a database 4187** can be used, a single callback function may be registered with the 4188** [database connection] to be invoked whenever an undefined collation 4189** sequence is required. 4190** 4191** ^If the function is registered using the sqlite3_collation_needed() API, 4192** then it is passed the names of undefined collation sequences as strings 4193** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4194** the names are passed as UTF-16 in machine native byte order. 4195** ^A call to either function replaces the existing collation-needed callback. 4196** 4197** ^(When the callback is invoked, the first argument passed is a copy 4198** of the second argument to sqlite3_collation_needed() or 4199** sqlite3_collation_needed16(). The second argument is the database 4200** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4201** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4202** sequence function required. The fourth parameter is the name of the 4203** required collation sequence.)^ 4204** 4205** The callback function should register the desired collation using 4206** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4207** [sqlite3_create_collation_v2()]. 4208*/ 4209SQLITE_API int sqlite3_collation_needed( 4210 sqlite3*, 4211 void*, 4212 void(*)(void*,sqlite3*,int eTextRep,const char*) 4213); 4214SQLITE_API int sqlite3_collation_needed16( 4215 sqlite3*, 4216 void*, 4217 void(*)(void*,sqlite3*,int eTextRep,const void*) 4218); 4219 4220#ifdef SQLITE_HAS_CODEC 4221/* 4222** Specify the key for an encrypted database. This routine should be 4223** called right after sqlite3_open(). 4224** 4225** The code to implement this API is not available in the public release 4226** of SQLite. 4227*/ 4228SQLITE_API int sqlite3_key( 4229 sqlite3 *db, /* Database to be rekeyed */ 4230 const void *pKey, int nKey /* The key */ 4231); 4232 4233/* 4234** Change the key on an open database. If the current database is not 4235** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4236** database is decrypted. 4237** 4238** The code to implement this API is not available in the public release 4239** of SQLite. 4240*/ 4241SQLITE_API int sqlite3_rekey( 4242 sqlite3 *db, /* Database to be rekeyed */ 4243 const void *pKey, int nKey /* The new key */ 4244); 4245 4246/* 4247** Specify the activation key for a SEE database. Unless 4248** activated, none of the SEE routines will work. 4249*/ 4250SQLITE_API void sqlite3_activate_see( 4251 const char *zPassPhrase /* Activation phrase */ 4252); 4253#endif 4254 4255#ifdef SQLITE_ENABLE_CEROD 4256/* 4257** Specify the activation key for a CEROD database. Unless 4258** activated, none of the CEROD routines will work. 4259*/ 4260SQLITE_API void sqlite3_activate_cerod( 4261 const char *zPassPhrase /* Activation phrase */ 4262); 4263#endif 4264 4265/* 4266** CAPI3REF: Suspend Execution For A Short Time 4267** 4268** The sqlite3_sleep() function causes the current thread to suspend execution 4269** for at least a number of milliseconds specified in its parameter. 4270** 4271** If the operating system does not support sleep requests with 4272** millisecond time resolution, then the time will be rounded up to 4273** the nearest second. The number of milliseconds of sleep actually 4274** requested from the operating system is returned. 4275** 4276** ^SQLite implements this interface by calling the xSleep() 4277** method of the default [sqlite3_vfs] object. If the xSleep() method 4278** of the default VFS is not implemented correctly, or not implemented at 4279** all, then the behavior of sqlite3_sleep() may deviate from the description 4280** in the previous paragraphs. 4281*/ 4282SQLITE_API int sqlite3_sleep(int); 4283 4284/* 4285** CAPI3REF: Name Of The Folder Holding Temporary Files 4286** 4287** ^(If this global variable is made to point to a string which is 4288** the name of a folder (a.k.a. directory), then all temporary files 4289** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4290** will be placed in that directory.)^ ^If this variable 4291** is a NULL pointer, then SQLite performs a search for an appropriate 4292** temporary file directory. 4293** 4294** It is not safe to read or modify this variable in more than one 4295** thread at a time. It is not safe to read or modify this variable 4296** if a [database connection] is being used at the same time in a separate 4297** thread. 4298** It is intended that this variable be set once 4299** as part of process initialization and before any SQLite interface 4300** routines have been called and that this variable remain unchanged 4301** thereafter. 4302** 4303** ^The [temp_store_directory pragma] may modify this variable and cause 4304** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4305** the [temp_store_directory pragma] always assumes that any string 4306** that this variable points to is held in memory obtained from 4307** [sqlite3_malloc] and the pragma may attempt to free that memory 4308** using [sqlite3_free]. 4309** Hence, if this variable is modified directly, either it should be 4310** made NULL or made to point to memory obtained from [sqlite3_malloc] 4311** or else the use of the [temp_store_directory pragma] should be avoided. 4312*/ 4313SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory; 4314 4315/* 4316** CAPI3REF: Test For Auto-Commit Mode 4317** KEYWORDS: {autocommit mode} 4318** 4319** ^The sqlite3_get_autocommit() interface returns non-zero or 4320** zero if the given database connection is or is not in autocommit mode, 4321** respectively. ^Autocommit mode is on by default. 4322** ^Autocommit mode is disabled by a [BEGIN] statement. 4323** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 4324** 4325** If certain kinds of errors occur on a statement within a multi-statement 4326** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 4327** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 4328** transaction might be rolled back automatically. The only way to 4329** find out whether SQLite automatically rolled back the transaction after 4330** an error is to use this function. 4331** 4332** If another thread changes the autocommit status of the database 4333** connection while this routine is running, then the return value 4334** is undefined. 4335*/ 4336SQLITE_API int sqlite3_get_autocommit(sqlite3*); 4337 4338/* 4339** CAPI3REF: Find The Database Handle Of A Prepared Statement 4340** 4341** ^The sqlite3_db_handle interface returns the [database connection] handle 4342** to which a [prepared statement] belongs. ^The [database connection] 4343** returned by sqlite3_db_handle is the same [database connection] 4344** that was the first argument 4345** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 4346** create the statement in the first place. 4347*/ 4348SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 4349 4350/* 4351** CAPI3REF: Find the next prepared statement 4352** 4353** ^This interface returns a pointer to the next [prepared statement] after 4354** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 4355** then this interface returns a pointer to the first prepared statement 4356** associated with the database connection pDb. ^If no prepared statement 4357** satisfies the conditions of this routine, it returns NULL. 4358** 4359** The [database connection] pointer D in a call to 4360** [sqlite3_next_stmt(D,S)] must refer to an open database 4361** connection and in particular must not be a NULL pointer. 4362*/ 4363SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 4364 4365/* 4366** CAPI3REF: Commit And Rollback Notification Callbacks 4367** 4368** ^The sqlite3_commit_hook() interface registers a callback 4369** function to be invoked whenever a transaction is [COMMIT | committed]. 4370** ^Any callback set by a previous call to sqlite3_commit_hook() 4371** for the same database connection is overridden. 4372** ^The sqlite3_rollback_hook() interface registers a callback 4373** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 4374** ^Any callback set by a previous call to sqlite3_rollback_hook() 4375** for the same database connection is overridden. 4376** ^The pArg argument is passed through to the callback. 4377** ^If the callback on a commit hook function returns non-zero, 4378** then the commit is converted into a rollback. 4379** 4380** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 4381** return the P argument from the previous call of the same function 4382** on the same [database connection] D, or NULL for 4383** the first call for each function on D. 4384** 4385** The callback implementation must not do anything that will modify 4386** the database connection that invoked the callback. Any actions 4387** to modify the database connection must be deferred until after the 4388** completion of the [sqlite3_step()] call that triggered the commit 4389** or rollback hook in the first place. 4390** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4391** database connections for the meaning of "modify" in this paragraph. 4392** 4393** ^Registering a NULL function disables the callback. 4394** 4395** ^When the commit hook callback routine returns zero, the [COMMIT] 4396** operation is allowed to continue normally. ^If the commit hook 4397** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 4398** ^The rollback hook is invoked on a rollback that results from a commit 4399** hook returning non-zero, just as it would be with any other rollback. 4400** 4401** ^For the purposes of this API, a transaction is said to have been 4402** rolled back if an explicit "ROLLBACK" statement is executed, or 4403** an error or constraint causes an implicit rollback to occur. 4404** ^The rollback callback is not invoked if a transaction is 4405** automatically rolled back because the database connection is closed. 4406** 4407** See also the [sqlite3_update_hook()] interface. 4408*/ 4409SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 4410SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 4411 4412/* 4413** CAPI3REF: Data Change Notification Callbacks 4414** 4415** ^The sqlite3_update_hook() interface registers a callback function 4416** with the [database connection] identified by the first argument 4417** to be invoked whenever a row is updated, inserted or deleted. 4418** ^Any callback set by a previous call to this function 4419** for the same database connection is overridden. 4420** 4421** ^The second argument is a pointer to the function to invoke when a 4422** row is updated, inserted or deleted. 4423** ^The first argument to the callback is a copy of the third argument 4424** to sqlite3_update_hook(). 4425** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 4426** or [SQLITE_UPDATE], depending on the operation that caused the callback 4427** to be invoked. 4428** ^The third and fourth arguments to the callback contain pointers to the 4429** database and table name containing the affected row. 4430** ^The final callback parameter is the [rowid] of the row. 4431** ^In the case of an update, this is the [rowid] after the update takes place. 4432** 4433** ^(The update hook is not invoked when internal system tables are 4434** modified (i.e. sqlite_master and sqlite_sequence).)^ 4435** 4436** ^In the current implementation, the update hook 4437** is not invoked when duplication rows are deleted because of an 4438** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 4439** invoked when rows are deleted using the [truncate optimization]. 4440** The exceptions defined in this paragraph might change in a future 4441** release of SQLite. 4442** 4443** The update hook implementation must not do anything that will modify 4444** the database connection that invoked the update hook. Any actions 4445** to modify the database connection must be deferred until after the 4446** completion of the [sqlite3_step()] call that triggered the update hook. 4447** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4448** database connections for the meaning of "modify" in this paragraph. 4449** 4450** ^The sqlite3_update_hook(D,C,P) function 4451** returns the P argument from the previous call 4452** on the same [database connection] D, or NULL for 4453** the first call on D. 4454** 4455** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4456** interfaces. 4457*/ 4458SQLITE_API void *sqlite3_update_hook( 4459 sqlite3*, 4460 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4461 void* 4462); 4463 4464/* 4465** CAPI3REF: Enable Or Disable Shared Pager Cache 4466** KEYWORDS: {shared cache} 4467** 4468** ^(This routine enables or disables the sharing of the database cache 4469** and schema data structures between [database connection | connections] 4470** to the same database. Sharing is enabled if the argument is true 4471** and disabled if the argument is false.)^ 4472** 4473** ^Cache sharing is enabled and disabled for an entire process. 4474** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4475** sharing was enabled or disabled for each thread separately. 4476** 4477** ^(The cache sharing mode set by this interface effects all subsequent 4478** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4479** Existing database connections continue use the sharing mode 4480** that was in effect at the time they were opened.)^ 4481** 4482** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4483** successfully. An [error code] is returned otherwise.)^ 4484** 4485** ^Shared cache is disabled by default. But this might change in 4486** future releases of SQLite. Applications that care about shared 4487** cache setting should set it explicitly. 4488** 4489** See Also: [SQLite Shared-Cache Mode] 4490*/ 4491SQLITE_API int sqlite3_enable_shared_cache(int); 4492 4493/* 4494** CAPI3REF: Attempt To Free Heap Memory 4495** 4496** ^The sqlite3_release_memory() interface attempts to free N bytes 4497** of heap memory by deallocating non-essential memory allocations 4498** held by the database library. Memory used to cache database 4499** pages to improve performance is an example of non-essential memory. 4500** ^sqlite3_release_memory() returns the number of bytes actually freed, 4501** which might be more or less than the amount requested. 4502** ^The sqlite3_release_memory() routine is a no-op returning zero 4503** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4504*/ 4505SQLITE_API int sqlite3_release_memory(int); 4506 4507/* 4508** CAPI3REF: Impose A Limit On Heap Size 4509** 4510** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 4511** soft limit on the amount of heap memory that may be allocated by SQLite. 4512** ^SQLite strives to keep heap memory utilization below the soft heap 4513** limit by reducing the number of pages held in the page cache 4514** as heap memory usages approaches the limit. 4515** ^The soft heap limit is "soft" because even though SQLite strives to stay 4516** below the limit, it will exceed the limit rather than generate 4517** an [SQLITE_NOMEM] error. In other words, the soft heap limit 4518** is advisory only. 4519** 4520** ^The return value from sqlite3_soft_heap_limit64() is the size of 4521** the soft heap limit prior to the call. ^If the argument N is negative 4522** then no change is made to the soft heap limit. Hence, the current 4523** size of the soft heap limit can be determined by invoking 4524** sqlite3_soft_heap_limit64() with a negative argument. 4525** 4526** ^If the argument N is zero then the soft heap limit is disabled. 4527** 4528** ^(The soft heap limit is not enforced in the current implementation 4529** if one or more of following conditions are true: 4530** 4531** <ul> 4532** <li> The soft heap limit is set to zero. 4533** <li> Memory accounting is disabled using a combination of the 4534** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 4535** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 4536** <li> An alternative page cache implementation is specified using 4537** [sqlite3_config]([SQLITE_CONFIG_PCACHE],...). 4538** <li> The page cache allocates from its own memory pool supplied 4539** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 4540** from the heap. 4541** </ul>)^ 4542** 4543** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 4544** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 4545** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 4546** the soft heap limit is enforced on every memory allocation. Without 4547** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 4548** when memory is allocated by the page cache. Testing suggests that because 4549** the page cache is the predominate memory user in SQLite, most 4550** applications will achieve adequate soft heap limit enforcement without 4551** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4552** 4553** The circumstances under which SQLite will enforce the soft heap limit may 4554** changes in future releases of SQLite. 4555*/ 4556SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 4557 4558/* 4559** CAPI3REF: Deprecated Soft Heap Limit Interface 4560** DEPRECATED 4561** 4562** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 4563** interface. This routine is provided for historical compatibility 4564** only. All new applications should use the 4565** [sqlite3_soft_heap_limit64()] interface rather than this one. 4566*/ 4567SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 4568 4569 4570/* 4571** CAPI3REF: Extract Metadata About A Column Of A Table 4572** 4573** ^This routine returns metadata about a specific column of a specific 4574** database table accessible using the [database connection] handle 4575** passed as the first function argument. 4576** 4577** ^The column is identified by the second, third and fourth parameters to 4578** this function. ^The second parameter is either the name of the database 4579** (i.e. "main", "temp", or an attached database) containing the specified 4580** table or NULL. ^If it is NULL, then all attached databases are searched 4581** for the table using the same algorithm used by the database engine to 4582** resolve unqualified table references. 4583** 4584** ^The third and fourth parameters to this function are the table and column 4585** name of the desired column, respectively. Neither of these parameters 4586** may be NULL. 4587** 4588** ^Metadata is returned by writing to the memory locations passed as the 5th 4589** and subsequent parameters to this function. ^Any of these arguments may be 4590** NULL, in which case the corresponding element of metadata is omitted. 4591** 4592** ^(<blockquote> 4593** <table border="1"> 4594** <tr><th> Parameter <th> Output<br>Type <th> Description 4595** 4596** <tr><td> 5th <td> const char* <td> Data type 4597** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4598** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4599** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4600** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4601** </table> 4602** </blockquote>)^ 4603** 4604** ^The memory pointed to by the character pointers returned for the 4605** declaration type and collation sequence is valid only until the next 4606** call to any SQLite API function. 4607** 4608** ^If the specified table is actually a view, an [error code] is returned. 4609** 4610** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4611** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4612** parameters are set for the explicitly declared column. ^(If there is no 4613** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4614** parameters are set as follows: 4615** 4616** <pre> 4617** data type: "INTEGER" 4618** collation sequence: "BINARY" 4619** not null: 0 4620** primary key: 1 4621** auto increment: 0 4622** </pre>)^ 4623** 4624** ^(This function may load one or more schemas from database files. If an 4625** error occurs during this process, or if the requested table or column 4626** cannot be found, an [error code] is returned and an error message left 4627** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4628** 4629** ^This API is only available if the library was compiled with the 4630** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4631*/ 4632SQLITE_API int sqlite3_table_column_metadata( 4633 sqlite3 *db, /* Connection handle */ 4634 const char *zDbName, /* Database name or NULL */ 4635 const char *zTableName, /* Table name */ 4636 const char *zColumnName, /* Column name */ 4637 char const **pzDataType, /* OUTPUT: Declared data type */ 4638 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4639 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4640 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4641 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4642); 4643 4644/* 4645** CAPI3REF: Load An Extension 4646** 4647** ^This interface loads an SQLite extension library from the named file. 4648** 4649** ^The sqlite3_load_extension() interface attempts to load an 4650** SQLite extension library contained in the file zFile. 4651** 4652** ^The entry point is zProc. 4653** ^zProc may be 0, in which case the name of the entry point 4654** defaults to "sqlite3_extension_init". 4655** ^The sqlite3_load_extension() interface returns 4656** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4657** ^If an error occurs and pzErrMsg is not 0, then the 4658** [sqlite3_load_extension()] interface shall attempt to 4659** fill *pzErrMsg with error message text stored in memory 4660** obtained from [sqlite3_malloc()]. The calling function 4661** should free this memory by calling [sqlite3_free()]. 4662** 4663** ^Extension loading must be enabled using 4664** [sqlite3_enable_load_extension()] prior to calling this API, 4665** otherwise an error will be returned. 4666** 4667** See also the [load_extension() SQL function]. 4668*/ 4669SQLITE_API int sqlite3_load_extension( 4670 sqlite3 *db, /* Load the extension into this database connection */ 4671 const char *zFile, /* Name of the shared library containing extension */ 4672 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4673 char **pzErrMsg /* Put error message here if not 0 */ 4674); 4675 4676/* 4677** CAPI3REF: Enable Or Disable Extension Loading 4678** 4679** ^So as not to open security holes in older applications that are 4680** unprepared to deal with extension loading, and as a means of disabling 4681** extension loading while evaluating user-entered SQL, the following API 4682** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4683** 4684** ^Extension loading is off by default. See ticket #1863. 4685** ^Call the sqlite3_enable_load_extension() routine with onoff==1 4686** to turn extension loading on and call it with onoff==0 to turn 4687** it back off again. 4688*/ 4689SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4690 4691/* 4692** CAPI3REF: Automatically Load Statically Linked Extensions 4693** 4694** ^This interface causes the xEntryPoint() function to be invoked for 4695** each new [database connection] that is created. The idea here is that 4696** xEntryPoint() is the entry point for a statically linked SQLite extension 4697** that is to be automatically loaded into all new database connections. 4698** 4699** ^(Even though the function prototype shows that xEntryPoint() takes 4700** no arguments and returns void, SQLite invokes xEntryPoint() with three 4701** arguments and expects and integer result as if the signature of the 4702** entry point where as follows: 4703** 4704** <blockquote><pre> 4705** int xEntryPoint( 4706** sqlite3 *db, 4707** const char **pzErrMsg, 4708** const struct sqlite3_api_routines *pThunk 4709** ); 4710** </pre></blockquote>)^ 4711** 4712** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 4713** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 4714** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 4715** is NULL before calling the xEntryPoint(). ^SQLite will invoke 4716** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 4717** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 4718** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 4719** 4720** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 4721** on the list of automatic extensions is a harmless no-op. ^No entry point 4722** will be called more than once for each database connection that is opened. 4723** 4724** See also: [sqlite3_reset_auto_extension()]. 4725*/ 4726SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4727 4728/* 4729** CAPI3REF: Reset Automatic Extension Loading 4730** 4731** ^This interface disables all automatic extensions previously 4732** registered using [sqlite3_auto_extension()]. 4733*/ 4734SQLITE_API void sqlite3_reset_auto_extension(void); 4735 4736/* 4737** The interface to the virtual-table mechanism is currently considered 4738** to be experimental. The interface might change in incompatible ways. 4739** If this is a problem for you, do not use the interface at this time. 4740** 4741** When the virtual-table mechanism stabilizes, we will declare the 4742** interface fixed, support it indefinitely, and remove this comment. 4743*/ 4744 4745/* 4746** Structures used by the virtual table interface 4747*/ 4748typedef struct sqlite3_vtab sqlite3_vtab; 4749typedef struct sqlite3_index_info sqlite3_index_info; 4750typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4751typedef struct sqlite3_module sqlite3_module; 4752 4753/* 4754** CAPI3REF: Virtual Table Object 4755** KEYWORDS: sqlite3_module {virtual table module} 4756** 4757** This structure, sometimes called a "virtual table module", 4758** defines the implementation of a [virtual tables]. 4759** This structure consists mostly of methods for the module. 4760** 4761** ^A virtual table module is created by filling in a persistent 4762** instance of this structure and passing a pointer to that instance 4763** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4764** ^The registration remains valid until it is replaced by a different 4765** module or until the [database connection] closes. The content 4766** of this structure must not change while it is registered with 4767** any database connection. 4768*/ 4769struct sqlite3_module { 4770 int iVersion; 4771 int (*xCreate)(sqlite3*, void *pAux, 4772 int argc, const char *const*argv, 4773 sqlite3_vtab **ppVTab, char**); 4774 int (*xConnect)(sqlite3*, void *pAux, 4775 int argc, const char *const*argv, 4776 sqlite3_vtab **ppVTab, char**); 4777 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4778 int (*xDisconnect)(sqlite3_vtab *pVTab); 4779 int (*xDestroy)(sqlite3_vtab *pVTab); 4780 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4781 int (*xClose)(sqlite3_vtab_cursor*); 4782 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4783 int argc, sqlite3_value **argv); 4784 int (*xNext)(sqlite3_vtab_cursor*); 4785 int (*xEof)(sqlite3_vtab_cursor*); 4786 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4787 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4788 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4789 int (*xBegin)(sqlite3_vtab *pVTab); 4790 int (*xSync)(sqlite3_vtab *pVTab); 4791 int (*xCommit)(sqlite3_vtab *pVTab); 4792 int (*xRollback)(sqlite3_vtab *pVTab); 4793 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4794 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4795 void **ppArg); 4796 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4797 /* The methods above are in version 1 of the sqlite_module object. Those 4798 ** below are for version 2 and greater. */ 4799 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 4800 int (*xRelease)(sqlite3_vtab *pVTab, int); 4801 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 4802}; 4803 4804/* 4805** CAPI3REF: Virtual Table Indexing Information 4806** KEYWORDS: sqlite3_index_info 4807** 4808** The sqlite3_index_info structure and its substructures is used as part 4809** of the [virtual table] interface to 4810** pass information into and receive the reply from the [xBestIndex] 4811** method of a [virtual table module]. The fields under **Inputs** are the 4812** inputs to xBestIndex and are read-only. xBestIndex inserts its 4813** results into the **Outputs** fields. 4814** 4815** ^(The aConstraint[] array records WHERE clause constraints of the form: 4816** 4817** <blockquote>column OP expr</blockquote> 4818** 4819** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 4820** stored in aConstraint[].op using one of the 4821** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 4822** ^(The index of the column is stored in 4823** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 4824** expr on the right-hand side can be evaluated (and thus the constraint 4825** is usable) and false if it cannot.)^ 4826** 4827** ^The optimizer automatically inverts terms of the form "expr OP column" 4828** and makes other simplifications to the WHERE clause in an attempt to 4829** get as many WHERE clause terms into the form shown above as possible. 4830** ^The aConstraint[] array only reports WHERE clause terms that are 4831** relevant to the particular virtual table being queried. 4832** 4833** ^Information about the ORDER BY clause is stored in aOrderBy[]. 4834** ^Each term of aOrderBy records a column of the ORDER BY clause. 4835** 4836** The [xBestIndex] method must fill aConstraintUsage[] with information 4837** about what parameters to pass to xFilter. ^If argvIndex>0 then 4838** the right-hand side of the corresponding aConstraint[] is evaluated 4839** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 4840** is true, then the constraint is assumed to be fully handled by the 4841** virtual table and is not checked again by SQLite.)^ 4842** 4843** ^The idxNum and idxPtr values are recorded and passed into the 4844** [xFilter] method. 4845** ^[sqlite3_free()] is used to free idxPtr if and only if 4846** needToFreeIdxPtr is true. 4847** 4848** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 4849** the correct order to satisfy the ORDER BY clause so that no separate 4850** sorting step is required. 4851** 4852** ^The estimatedCost value is an estimate of the cost of doing the 4853** particular lookup. A full scan of a table with N entries should have 4854** a cost of N. A binary search of a table of N entries should have a 4855** cost of approximately log(N). 4856*/ 4857struct sqlite3_index_info { 4858 /* Inputs */ 4859 int nConstraint; /* Number of entries in aConstraint */ 4860 struct sqlite3_index_constraint { 4861 int iColumn; /* Column on left-hand side of constraint */ 4862 unsigned char op; /* Constraint operator */ 4863 unsigned char usable; /* True if this constraint is usable */ 4864 int iTermOffset; /* Used internally - xBestIndex should ignore */ 4865 } *aConstraint; /* Table of WHERE clause constraints */ 4866 int nOrderBy; /* Number of terms in the ORDER BY clause */ 4867 struct sqlite3_index_orderby { 4868 int iColumn; /* Column number */ 4869 unsigned char desc; /* True for DESC. False for ASC. */ 4870 } *aOrderBy; /* The ORDER BY clause */ 4871 /* Outputs */ 4872 struct sqlite3_index_constraint_usage { 4873 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 4874 unsigned char omit; /* Do not code a test for this constraint */ 4875 } *aConstraintUsage; 4876 int idxNum; /* Number used to identify the index */ 4877 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 4878 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 4879 int orderByConsumed; /* True if output is already ordered */ 4880 double estimatedCost; /* Estimated cost of using this index */ 4881}; 4882 4883/* 4884** CAPI3REF: Virtual Table Constraint Operator Codes 4885** 4886** These macros defined the allowed values for the 4887** [sqlite3_index_info].aConstraint[].op field. Each value represents 4888** an operator that is part of a constraint term in the wHERE clause of 4889** a query that uses a [virtual table]. 4890*/ 4891#define SQLITE_INDEX_CONSTRAINT_EQ 2 4892#define SQLITE_INDEX_CONSTRAINT_GT 4 4893#define SQLITE_INDEX_CONSTRAINT_LE 8 4894#define SQLITE_INDEX_CONSTRAINT_LT 16 4895#define SQLITE_INDEX_CONSTRAINT_GE 32 4896#define SQLITE_INDEX_CONSTRAINT_MATCH 64 4897 4898/* 4899** CAPI3REF: Register A Virtual Table Implementation 4900** 4901** ^These routines are used to register a new [virtual table module] name. 4902** ^Module names must be registered before 4903** creating a new [virtual table] using the module and before using a 4904** preexisting [virtual table] for the module. 4905** 4906** ^The module name is registered on the [database connection] specified 4907** by the first parameter. ^The name of the module is given by the 4908** second parameter. ^The third parameter is a pointer to 4909** the implementation of the [virtual table module]. ^The fourth 4910** parameter is an arbitrary client data pointer that is passed through 4911** into the [xCreate] and [xConnect] methods of the virtual table module 4912** when a new virtual table is be being created or reinitialized. 4913** 4914** ^The sqlite3_create_module_v2() interface has a fifth parameter which 4915** is a pointer to a destructor for the pClientData. ^SQLite will 4916** invoke the destructor function (if it is not NULL) when SQLite 4917** no longer needs the pClientData pointer. ^The destructor will also 4918** be invoked if the call to sqlite3_create_module_v2() fails. 4919** ^The sqlite3_create_module() 4920** interface is equivalent to sqlite3_create_module_v2() with a NULL 4921** destructor. 4922*/ 4923SQLITE_API int sqlite3_create_module( 4924 sqlite3 *db, /* SQLite connection to register module with */ 4925 const char *zName, /* Name of the module */ 4926 const sqlite3_module *p, /* Methods for the module */ 4927 void *pClientData /* Client data for xCreate/xConnect */ 4928); 4929SQLITE_API int sqlite3_create_module_v2( 4930 sqlite3 *db, /* SQLite connection to register module with */ 4931 const char *zName, /* Name of the module */ 4932 const sqlite3_module *p, /* Methods for the module */ 4933 void *pClientData, /* Client data for xCreate/xConnect */ 4934 void(*xDestroy)(void*) /* Module destructor function */ 4935); 4936 4937/* 4938** CAPI3REF: Virtual Table Instance Object 4939** KEYWORDS: sqlite3_vtab 4940** 4941** Every [virtual table module] implementation uses a subclass 4942** of this object to describe a particular instance 4943** of the [virtual table]. Each subclass will 4944** be tailored to the specific needs of the module implementation. 4945** The purpose of this superclass is to define certain fields that are 4946** common to all module implementations. 4947** 4948** ^Virtual tables methods can set an error message by assigning a 4949** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 4950** take care that any prior string is freed by a call to [sqlite3_free()] 4951** prior to assigning a new string to zErrMsg. ^After the error message 4952** is delivered up to the client application, the string will be automatically 4953** freed by sqlite3_free() and the zErrMsg field will be zeroed. 4954*/ 4955struct sqlite3_vtab { 4956 const sqlite3_module *pModule; /* The module for this virtual table */ 4957 int nRef; /* NO LONGER USED */ 4958 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 4959 /* Virtual table implementations will typically add additional fields */ 4960}; 4961 4962/* 4963** CAPI3REF: Virtual Table Cursor Object 4964** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 4965** 4966** Every [virtual table module] implementation uses a subclass of the 4967** following structure to describe cursors that point into the 4968** [virtual table] and are used 4969** to loop through the virtual table. Cursors are created using the 4970** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 4971** by the [sqlite3_module.xClose | xClose] method. Cursors are used 4972** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 4973** of the module. Each module implementation will define 4974** the content of a cursor structure to suit its own needs. 4975** 4976** This superclass exists in order to define fields of the cursor that 4977** are common to all implementations. 4978*/ 4979struct sqlite3_vtab_cursor { 4980 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 4981 /* Virtual table implementations will typically add additional fields */ 4982}; 4983 4984/* 4985** CAPI3REF: Declare The Schema Of A Virtual Table 4986** 4987** ^The [xCreate] and [xConnect] methods of a 4988** [virtual table module] call this interface 4989** to declare the format (the names and datatypes of the columns) of 4990** the virtual tables they implement. 4991*/ 4992SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 4993 4994/* 4995** CAPI3REF: Overload A Function For A Virtual Table 4996** 4997** ^(Virtual tables can provide alternative implementations of functions 4998** using the [xFindFunction] method of the [virtual table module]. 4999** But global versions of those functions 5000** must exist in order to be overloaded.)^ 5001** 5002** ^(This API makes sure a global version of a function with a particular 5003** name and number of parameters exists. If no such function exists 5004** before this API is called, a new function is created.)^ ^The implementation 5005** of the new function always causes an exception to be thrown. So 5006** the new function is not good for anything by itself. Its only 5007** purpose is to be a placeholder function that can be overloaded 5008** by a [virtual table]. 5009*/ 5010SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5011 5012/* 5013** The interface to the virtual-table mechanism defined above (back up 5014** to a comment remarkably similar to this one) is currently considered 5015** to be experimental. The interface might change in incompatible ways. 5016** If this is a problem for you, do not use the interface at this time. 5017** 5018** When the virtual-table mechanism stabilizes, we will declare the 5019** interface fixed, support it indefinitely, and remove this comment. 5020*/ 5021 5022/* 5023** CAPI3REF: A Handle To An Open BLOB 5024** KEYWORDS: {BLOB handle} {BLOB handles} 5025** 5026** An instance of this object represents an open BLOB on which 5027** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5028** ^Objects of this type are created by [sqlite3_blob_open()] 5029** and destroyed by [sqlite3_blob_close()]. 5030** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5031** can be used to read or write small subsections of the BLOB. 5032** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5033*/ 5034typedef struct sqlite3_blob sqlite3_blob; 5035 5036/* 5037** CAPI3REF: Open A BLOB For Incremental I/O 5038** 5039** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5040** in row iRow, column zColumn, table zTable in database zDb; 5041** in other words, the same BLOB that would be selected by: 5042** 5043** <pre> 5044** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5045** </pre>)^ 5046** 5047** ^If the flags parameter is non-zero, then the BLOB is opened for read 5048** and write access. ^If it is zero, the BLOB is opened for read access. 5049** ^It is not possible to open a column that is part of an index or primary 5050** key for writing. ^If [foreign key constraints] are enabled, it is 5051** not possible to open a column that is part of a [child key] for writing. 5052** 5053** ^Note that the database name is not the filename that contains 5054** the database but rather the symbolic name of the database that 5055** appears after the AS keyword when the database is connected using [ATTACH]. 5056** ^For the main database file, the database name is "main". 5057** ^For TEMP tables, the database name is "temp". 5058** 5059** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 5060** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 5061** to be a null pointer.)^ 5062** ^This function sets the [database connection] error code and message 5063** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 5064** functions. ^Note that the *ppBlob variable is always initialized in a 5065** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 5066** regardless of the success or failure of this routine. 5067** 5068** ^(If the row that a BLOB handle points to is modified by an 5069** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5070** then the BLOB handle is marked as "expired". 5071** This is true if any column of the row is changed, even a column 5072** other than the one the BLOB handle is open on.)^ 5073** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5074** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5075** ^(Changes written into a BLOB prior to the BLOB expiring are not 5076** rolled back by the expiration of the BLOB. Such changes will eventually 5077** commit if the transaction continues to completion.)^ 5078** 5079** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5080** the opened blob. ^The size of a blob may not be changed by this 5081** interface. Use the [UPDATE] SQL command to change the size of a 5082** blob. 5083** 5084** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5085** and the built-in [zeroblob] SQL function can be used, if desired, 5086** to create an empty, zero-filled blob in which to read or write using 5087** this interface. 5088** 5089** To avoid a resource leak, every open [BLOB handle] should eventually 5090** be released by a call to [sqlite3_blob_close()]. 5091*/ 5092SQLITE_API int sqlite3_blob_open( 5093 sqlite3*, 5094 const char *zDb, 5095 const char *zTable, 5096 const char *zColumn, 5097 sqlite3_int64 iRow, 5098 int flags, 5099 sqlite3_blob **ppBlob 5100); 5101 5102/* 5103** CAPI3REF: Move a BLOB Handle to a New Row 5104** 5105** ^This function is used to move an existing blob handle so that it points 5106** to a different row of the same database table. ^The new row is identified 5107** by the rowid value passed as the second argument. Only the row can be 5108** changed. ^The database, table and column on which the blob handle is open 5109** remain the same. Moving an existing blob handle to a new row can be 5110** faster than closing the existing handle and opening a new one. 5111** 5112** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5113** it must exist and there must be either a blob or text value stored in 5114** the nominated column.)^ ^If the new row is not present in the table, or if 5115** it does not contain a blob or text value, or if another error occurs, an 5116** SQLite error code is returned and the blob handle is considered aborted. 5117** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5118** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5119** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5120** always returns zero. 5121** 5122** ^This function sets the database handle error code and message. 5123*/ 5124SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5125 5126/* 5127** CAPI3REF: Close A BLOB Handle 5128** 5129** ^Closes an open [BLOB handle]. 5130** 5131** ^Closing a BLOB shall cause the current transaction to commit 5132** if there are no other BLOBs, no pending prepared statements, and the 5133** database connection is in [autocommit mode]. 5134** ^If any writes were made to the BLOB, they might be held in cache 5135** until the close operation if they will fit. 5136** 5137** ^(Closing the BLOB often forces the changes 5138** out to disk and so if any I/O errors occur, they will likely occur 5139** at the time when the BLOB is closed. Any errors that occur during 5140** closing are reported as a non-zero return value.)^ 5141** 5142** ^(The BLOB is closed unconditionally. Even if this routine returns 5143** an error code, the BLOB is still closed.)^ 5144** 5145** ^Calling this routine with a null pointer (such as would be returned 5146** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 5147*/ 5148SQLITE_API int sqlite3_blob_close(sqlite3_blob *); 5149 5150/* 5151** CAPI3REF: Return The Size Of An Open BLOB 5152** 5153** ^Returns the size in bytes of the BLOB accessible via the 5154** successfully opened [BLOB handle] in its only argument. ^The 5155** incremental blob I/O routines can only read or overwriting existing 5156** blob content; they cannot change the size of a blob. 5157** 5158** This routine only works on a [BLOB handle] which has been created 5159** by a prior successful call to [sqlite3_blob_open()] and which has not 5160** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5161** to this routine results in undefined and probably undesirable behavior. 5162*/ 5163SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *); 5164 5165/* 5166** CAPI3REF: Read Data From A BLOB Incrementally 5167** 5168** ^(This function is used to read data from an open [BLOB handle] into a 5169** caller-supplied buffer. N bytes of data are copied into buffer Z 5170** from the open BLOB, starting at offset iOffset.)^ 5171** 5172** ^If offset iOffset is less than N bytes from the end of the BLOB, 5173** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 5174** less than zero, [SQLITE_ERROR] is returned and no data is read. 5175** ^The size of the blob (and hence the maximum value of N+iOffset) 5176** can be determined using the [sqlite3_blob_bytes()] interface. 5177** 5178** ^An attempt to read from an expired [BLOB handle] fails with an 5179** error code of [SQLITE_ABORT]. 5180** 5181** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 5182** Otherwise, an [error code] or an [extended error code] is returned.)^ 5183** 5184** This routine only works on a [BLOB handle] which has been created 5185** by a prior successful call to [sqlite3_blob_open()] and which has not 5186** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5187** to this routine results in undefined and probably undesirable behavior. 5188** 5189** See also: [sqlite3_blob_write()]. 5190*/ 5191SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 5192 5193/* 5194** CAPI3REF: Write Data Into A BLOB Incrementally 5195** 5196** ^This function is used to write data into an open [BLOB handle] from a 5197** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 5198** into the open BLOB, starting at offset iOffset. 5199** 5200** ^If the [BLOB handle] passed as the first argument was not opened for 5201** writing (the flags parameter to [sqlite3_blob_open()] was zero), 5202** this function returns [SQLITE_READONLY]. 5203** 5204** ^This function may only modify the contents of the BLOB; it is 5205** not possible to increase the size of a BLOB using this API. 5206** ^If offset iOffset is less than N bytes from the end of the BLOB, 5207** [SQLITE_ERROR] is returned and no data is written. ^If N is 5208** less than zero [SQLITE_ERROR] is returned and no data is written. 5209** The size of the BLOB (and hence the maximum value of N+iOffset) 5210** can be determined using the [sqlite3_blob_bytes()] interface. 5211** 5212** ^An attempt to write to an expired [BLOB handle] fails with an 5213** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 5214** before the [BLOB handle] expired are not rolled back by the 5215** expiration of the handle, though of course those changes might 5216** have been overwritten by the statement that expired the BLOB handle 5217** or by other independent statements. 5218** 5219** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 5220** Otherwise, an [error code] or an [extended error code] is returned.)^ 5221** 5222** This routine only works on a [BLOB handle] which has been created 5223** by a prior successful call to [sqlite3_blob_open()] and which has not 5224** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5225** to this routine results in undefined and probably undesirable behavior. 5226** 5227** See also: [sqlite3_blob_read()]. 5228*/ 5229SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 5230 5231/* 5232** CAPI3REF: Virtual File System Objects 5233** 5234** A virtual filesystem (VFS) is an [sqlite3_vfs] object 5235** that SQLite uses to interact 5236** with the underlying operating system. Most SQLite builds come with a 5237** single default VFS that is appropriate for the host computer. 5238** New VFSes can be registered and existing VFSes can be unregistered. 5239** The following interfaces are provided. 5240** 5241** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 5242** ^Names are case sensitive. 5243** ^Names are zero-terminated UTF-8 strings. 5244** ^If there is no match, a NULL pointer is returned. 5245** ^If zVfsName is NULL then the default VFS is returned. 5246** 5247** ^New VFSes are registered with sqlite3_vfs_register(). 5248** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 5249** ^The same VFS can be registered multiple times without injury. 5250** ^To make an existing VFS into the default VFS, register it again 5251** with the makeDflt flag set. If two different VFSes with the 5252** same name are registered, the behavior is undefined. If a 5253** VFS is registered with a name that is NULL or an empty string, 5254** then the behavior is undefined. 5255** 5256** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 5257** ^(If the default VFS is unregistered, another VFS is chosen as 5258** the default. The choice for the new VFS is arbitrary.)^ 5259*/ 5260SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 5261SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 5262SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*); 5263 5264/* 5265** CAPI3REF: Mutexes 5266** 5267** The SQLite core uses these routines for thread 5268** synchronization. Though they are intended for internal 5269** use by SQLite, code that links against SQLite is 5270** permitted to use any of these routines. 5271** 5272** The SQLite source code contains multiple implementations 5273** of these mutex routines. An appropriate implementation 5274** is selected automatically at compile-time. ^(The following 5275** implementations are available in the SQLite core: 5276** 5277** <ul> 5278** <li> SQLITE_MUTEX_OS2 5279** <li> SQLITE_MUTEX_PTHREAD 5280** <li> SQLITE_MUTEX_W32 5281** <li> SQLITE_MUTEX_NOOP 5282** </ul>)^ 5283** 5284** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 5285** that does no real locking and is appropriate for use in 5286** a single-threaded application. ^The SQLITE_MUTEX_OS2, 5287** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations 5288** are appropriate for use on OS/2, Unix, and Windows. 5289** 5290** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 5291** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 5292** implementation is included with the library. In this case the 5293** application must supply a custom mutex implementation using the 5294** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 5295** before calling sqlite3_initialize() or any other public sqlite3_ 5296** function that calls sqlite3_initialize().)^ 5297** 5298** ^The sqlite3_mutex_alloc() routine allocates a new 5299** mutex and returns a pointer to it. ^If it returns NULL 5300** that means that a mutex could not be allocated. ^SQLite 5301** will unwind its stack and return an error. ^(The argument 5302** to sqlite3_mutex_alloc() is one of these integer constants: 5303** 5304** <ul> 5305** <li> SQLITE_MUTEX_FAST 5306** <li> SQLITE_MUTEX_RECURSIVE 5307** <li> SQLITE_MUTEX_STATIC_MASTER 5308** <li> SQLITE_MUTEX_STATIC_MEM 5309** <li> SQLITE_MUTEX_STATIC_MEM2 5310** <li> SQLITE_MUTEX_STATIC_PRNG 5311** <li> SQLITE_MUTEX_STATIC_LRU 5312** <li> SQLITE_MUTEX_STATIC_LRU2 5313** </ul>)^ 5314** 5315** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 5316** cause sqlite3_mutex_alloc() to create 5317** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 5318** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 5319** The mutex implementation does not need to make a distinction 5320** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 5321** not want to. ^SQLite will only request a recursive mutex in 5322** cases where it really needs one. ^If a faster non-recursive mutex 5323** implementation is available on the host platform, the mutex subsystem 5324** might return such a mutex in response to SQLITE_MUTEX_FAST. 5325** 5326** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 5327** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 5328** a pointer to a static preexisting mutex. ^Six static mutexes are 5329** used by the current version of SQLite. Future versions of SQLite 5330** may add additional static mutexes. Static mutexes are for internal 5331** use by SQLite only. Applications that use SQLite mutexes should 5332** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 5333** SQLITE_MUTEX_RECURSIVE. 5334** 5335** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 5336** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 5337** returns a different mutex on every call. ^But for the static 5338** mutex types, the same mutex is returned on every call that has 5339** the same type number. 5340** 5341** ^The sqlite3_mutex_free() routine deallocates a previously 5342** allocated dynamic mutex. ^SQLite is careful to deallocate every 5343** dynamic mutex that it allocates. The dynamic mutexes must not be in 5344** use when they are deallocated. Attempting to deallocate a static 5345** mutex results in undefined behavior. ^SQLite never deallocates 5346** a static mutex. 5347** 5348** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 5349** to enter a mutex. ^If another thread is already within the mutex, 5350** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 5351** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 5352** upon successful entry. ^(Mutexes created using 5353** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 5354** In such cases the, 5355** mutex must be exited an equal number of times before another thread 5356** can enter.)^ ^(If the same thread tries to enter any other 5357** kind of mutex more than once, the behavior is undefined. 5358** SQLite will never exhibit 5359** such behavior in its own use of mutexes.)^ 5360** 5361** ^(Some systems (for example, Windows 95) do not support the operation 5362** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 5363** will always return SQLITE_BUSY. The SQLite core only ever uses 5364** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 5365** 5366** ^The sqlite3_mutex_leave() routine exits a mutex that was 5367** previously entered by the same thread. ^(The behavior 5368** is undefined if the mutex is not currently entered by the 5369** calling thread or is not currently allocated. SQLite will 5370** never do either.)^ 5371** 5372** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 5373** sqlite3_mutex_leave() is a NULL pointer, then all three routines 5374** behave as no-ops. 5375** 5376** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 5377*/ 5378SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int); 5379SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*); 5380SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*); 5381SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*); 5382SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*); 5383 5384/* 5385** CAPI3REF: Mutex Methods Object 5386** 5387** An instance of this structure defines the low-level routines 5388** used to allocate and use mutexes. 5389** 5390** Usually, the default mutex implementations provided by SQLite are 5391** sufficient, however the user has the option of substituting a custom 5392** implementation for specialized deployments or systems for which SQLite 5393** does not provide a suitable implementation. In this case, the user 5394** creates and populates an instance of this structure to pass 5395** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 5396** Additionally, an instance of this structure can be used as an 5397** output variable when querying the system for the current mutex 5398** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 5399** 5400** ^The xMutexInit method defined by this structure is invoked as 5401** part of system initialization by the sqlite3_initialize() function. 5402** ^The xMutexInit routine is called by SQLite exactly once for each 5403** effective call to [sqlite3_initialize()]. 5404** 5405** ^The xMutexEnd method defined by this structure is invoked as 5406** part of system shutdown by the sqlite3_shutdown() function. The 5407** implementation of this method is expected to release all outstanding 5408** resources obtained by the mutex methods implementation, especially 5409** those obtained by the xMutexInit method. ^The xMutexEnd() 5410** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 5411** 5412** ^(The remaining seven methods defined by this structure (xMutexAlloc, 5413** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 5414** xMutexNotheld) implement the following interfaces (respectively): 5415** 5416** <ul> 5417** <li> [sqlite3_mutex_alloc()] </li> 5418** <li> [sqlite3_mutex_free()] </li> 5419** <li> [sqlite3_mutex_enter()] </li> 5420** <li> [sqlite3_mutex_try()] </li> 5421** <li> [sqlite3_mutex_leave()] </li> 5422** <li> [sqlite3_mutex_held()] </li> 5423** <li> [sqlite3_mutex_notheld()] </li> 5424** </ul>)^ 5425** 5426** The only difference is that the public sqlite3_XXX functions enumerated 5427** above silently ignore any invocations that pass a NULL pointer instead 5428** of a valid mutex handle. The implementations of the methods defined 5429** by this structure are not required to handle this case, the results 5430** of passing a NULL pointer instead of a valid mutex handle are undefined 5431** (i.e. it is acceptable to provide an implementation that segfaults if 5432** it is passed a NULL pointer). 5433** 5434** The xMutexInit() method must be threadsafe. ^It must be harmless to 5435** invoke xMutexInit() multiple times within the same process and without 5436** intervening calls to xMutexEnd(). Second and subsequent calls to 5437** xMutexInit() must be no-ops. 5438** 5439** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 5440** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 5441** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 5442** memory allocation for a fast or recursive mutex. 5443** 5444** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 5445** called, but only if the prior call to xMutexInit returned SQLITE_OK. 5446** If xMutexInit fails in any way, it is expected to clean up after itself 5447** prior to returning. 5448*/ 5449typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 5450struct sqlite3_mutex_methods { 5451 int (*xMutexInit)(void); 5452 int (*xMutexEnd)(void); 5453 sqlite3_mutex *(*xMutexAlloc)(int); 5454 void (*xMutexFree)(sqlite3_mutex *); 5455 void (*xMutexEnter)(sqlite3_mutex *); 5456 int (*xMutexTry)(sqlite3_mutex *); 5457 void (*xMutexLeave)(sqlite3_mutex *); 5458 int (*xMutexHeld)(sqlite3_mutex *); 5459 int (*xMutexNotheld)(sqlite3_mutex *); 5460}; 5461 5462/* 5463** CAPI3REF: Mutex Verification Routines 5464** 5465** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 5466** are intended for use inside assert() statements. ^The SQLite core 5467** never uses these routines except inside an assert() and applications 5468** are advised to follow the lead of the core. ^The SQLite core only 5469** provides implementations for these routines when it is compiled 5470** with the SQLITE_DEBUG flag. ^External mutex implementations 5471** are only required to provide these routines if SQLITE_DEBUG is 5472** defined and if NDEBUG is not defined. 5473** 5474** ^These routines should return true if the mutex in their argument 5475** is held or not held, respectively, by the calling thread. 5476** 5477** ^The implementation is not required to provided versions of these 5478** routines that actually work. If the implementation does not provide working 5479** versions of these routines, it should at least provide stubs that always 5480** return true so that one does not get spurious assertion failures. 5481** 5482** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 5483** the routine should return 1. This seems counter-intuitive since 5484** clearly the mutex cannot be held if it does not exist. But 5485** the reason the mutex does not exist is because the build is not 5486** using mutexes. And we do not want the assert() containing the 5487** call to sqlite3_mutex_held() to fail, so a non-zero return is 5488** the appropriate thing to do. ^The sqlite3_mutex_notheld() 5489** interface should also return 1 when given a NULL pointer. 5490*/ 5491#ifndef NDEBUG 5492SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*); 5493SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*); 5494#endif 5495 5496/* 5497** CAPI3REF: Mutex Types 5498** 5499** The [sqlite3_mutex_alloc()] interface takes a single argument 5500** which is one of these integer constants. 5501** 5502** The set of static mutexes may change from one SQLite release to the 5503** next. Applications that override the built-in mutex logic must be 5504** prepared to accommodate additional static mutexes. 5505*/ 5506#define SQLITE_MUTEX_FAST 0 5507#define SQLITE_MUTEX_RECURSIVE 1 5508#define SQLITE_MUTEX_STATIC_MASTER 2 5509#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 5510#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 5511#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 5512#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 5513#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 5514#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 5515#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 5516 5517/* 5518** CAPI3REF: Retrieve the mutex for a database connection 5519** 5520** ^This interface returns a pointer the [sqlite3_mutex] object that 5521** serializes access to the [database connection] given in the argument 5522** when the [threading mode] is Serialized. 5523** ^If the [threading mode] is Single-thread or Multi-thread then this 5524** routine returns a NULL pointer. 5525*/ 5526SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 5527 5528/* 5529** CAPI3REF: Low-Level Control Of Database Files 5530** 5531** ^The [sqlite3_file_control()] interface makes a direct call to the 5532** xFileControl method for the [sqlite3_io_methods] object associated 5533** with a particular database identified by the second argument. ^The 5534** name of the database is "main" for the main database or "temp" for the 5535** TEMP database, or the name that appears after the AS keyword for 5536** databases that are added using the [ATTACH] SQL command. 5537** ^A NULL pointer can be used in place of "main" to refer to the 5538** main database file. 5539** ^The third and fourth parameters to this routine 5540** are passed directly through to the second and third parameters of 5541** the xFileControl method. ^The return value of the xFileControl 5542** method becomes the return value of this routine. 5543** 5544** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 5545** a pointer to the underlying [sqlite3_file] object to be written into 5546** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 5547** case is a short-circuit path which does not actually invoke the 5548** underlying sqlite3_io_methods.xFileControl method. 5549** 5550** ^If the second parameter (zDbName) does not match the name of any 5551** open database file, then SQLITE_ERROR is returned. ^This error 5552** code is not remembered and will not be recalled by [sqlite3_errcode()] 5553** or [sqlite3_errmsg()]. The underlying xFileControl method might 5554** also return SQLITE_ERROR. There is no way to distinguish between 5555** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5556** xFileControl method. 5557** 5558** See also: [SQLITE_FCNTL_LOCKSTATE] 5559*/ 5560SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5561 5562/* 5563** CAPI3REF: Testing Interface 5564** 5565** ^The sqlite3_test_control() interface is used to read out internal 5566** state of SQLite and to inject faults into SQLite for testing 5567** purposes. ^The first parameter is an operation code that determines 5568** the number, meaning, and operation of all subsequent parameters. 5569** 5570** This interface is not for use by applications. It exists solely 5571** for verifying the correct operation of the SQLite library. Depending 5572** on how the SQLite library is compiled, this interface might not exist. 5573** 5574** The details of the operation codes, their meanings, the parameters 5575** they take, and what they do are all subject to change without notice. 5576** Unlike most of the SQLite API, this function is not guaranteed to 5577** operate consistently from one release to the next. 5578*/ 5579SQLITE_API int sqlite3_test_control(int op, ...); 5580 5581/* 5582** CAPI3REF: Testing Interface Operation Codes 5583** 5584** These constants are the valid operation code parameters used 5585** as the first argument to [sqlite3_test_control()]. 5586** 5587** These parameters and their meanings are subject to change 5588** without notice. These values are for testing purposes only. 5589** Applications should not use any of these parameters or the 5590** [sqlite3_test_control()] interface. 5591*/ 5592#define SQLITE_TESTCTRL_FIRST 5 5593#define SQLITE_TESTCTRL_PRNG_SAVE 5 5594#define SQLITE_TESTCTRL_PRNG_RESTORE 6 5595#define SQLITE_TESTCTRL_PRNG_RESET 7 5596#define SQLITE_TESTCTRL_BITVEC_TEST 8 5597#define SQLITE_TESTCTRL_FAULT_INSTALL 9 5598#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5599#define SQLITE_TESTCTRL_PENDING_BYTE 11 5600#define SQLITE_TESTCTRL_ASSERT 12 5601#define SQLITE_TESTCTRL_ALWAYS 13 5602#define SQLITE_TESTCTRL_RESERVE 14 5603#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 5604#define SQLITE_TESTCTRL_ISKEYWORD 16 5605#define SQLITE_TESTCTRL_PGHDRSZ 17 5606#define SQLITE_TESTCTRL_SCRATCHMALLOC 18 5607#define SQLITE_TESTCTRL_LOCALTIME_FAULT 19 5608#define SQLITE_TESTCTRL_LAST 19 5609 5610/* 5611** CAPI3REF: SQLite Runtime Status 5612** 5613** ^This interface is used to retrieve runtime status information 5614** about the performance of SQLite, and optionally to reset various 5615** highwater marks. ^The first argument is an integer code for 5616** the specific parameter to measure. ^(Recognized integer codes 5617** are of the form [status parameters | SQLITE_STATUS_...].)^ 5618** ^The current value of the parameter is returned into *pCurrent. 5619** ^The highest recorded value is returned in *pHighwater. ^If the 5620** resetFlag is true, then the highest record value is reset after 5621** *pHighwater is written. ^(Some parameters do not record the highest 5622** value. For those parameters 5623** nothing is written into *pHighwater and the resetFlag is ignored.)^ 5624** ^(Other parameters record only the highwater mark and not the current 5625** value. For these latter parameters nothing is written into *pCurrent.)^ 5626** 5627** ^The sqlite3_status() routine returns SQLITE_OK on success and a 5628** non-zero [error code] on failure. 5629** 5630** This routine is threadsafe but is not atomic. This routine can be 5631** called while other threads are running the same or different SQLite 5632** interfaces. However the values returned in *pCurrent and 5633** *pHighwater reflect the status of SQLite at different points in time 5634** and it is possible that another thread might change the parameter 5635** in between the times when *pCurrent and *pHighwater are written. 5636** 5637** See also: [sqlite3_db_status()] 5638*/ 5639SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 5640 5641 5642/* 5643** CAPI3REF: Status Parameters 5644** KEYWORDS: {status parameters} 5645** 5646** These integer constants designate various run-time status parameters 5647** that can be returned by [sqlite3_status()]. 5648** 5649** <dl> 5650** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 5651** <dd>This parameter is the current amount of memory checked out 5652** using [sqlite3_malloc()], either directly or indirectly. The 5653** figure includes calls made to [sqlite3_malloc()] by the application 5654** and internal memory usage by the SQLite library. Scratch memory 5655** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 5656** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 5657** this parameter. The amount returned is the sum of the allocation 5658** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 5659** 5660** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 5661** <dd>This parameter records the largest memory allocation request 5662** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 5663** internal equivalents). Only the value returned in the 5664** *pHighwater parameter to [sqlite3_status()] is of interest. 5665** The value written into the *pCurrent parameter is undefined.</dd>)^ 5666** 5667** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 5668** <dd>This parameter records the number of separate memory allocations 5669** currently checked out.</dd>)^ 5670** 5671** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 5672** <dd>This parameter returns the number of pages used out of the 5673** [pagecache memory allocator] that was configured using 5674** [SQLITE_CONFIG_PAGECACHE]. The 5675** value returned is in pages, not in bytes.</dd>)^ 5676** 5677** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 5678** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5679** <dd>This parameter returns the number of bytes of page cache 5680** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 5681** buffer and where forced to overflow to [sqlite3_malloc()]. The 5682** returned value includes allocations that overflowed because they 5683** where too large (they were larger than the "sz" parameter to 5684** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 5685** no space was left in the page cache.</dd>)^ 5686** 5687** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 5688** <dd>This parameter records the largest memory allocation request 5689** handed to [pagecache memory allocator]. Only the value returned in the 5690** *pHighwater parameter to [sqlite3_status()] is of interest. 5691** The value written into the *pCurrent parameter is undefined.</dd>)^ 5692** 5693** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 5694** <dd>This parameter returns the number of allocations used out of the 5695** [scratch memory allocator] configured using 5696** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5697** in bytes. Since a single thread may only have one scratch allocation 5698** outstanding at time, this parameter also reports the number of threads 5699** using scratch memory at the same time.</dd>)^ 5700** 5701** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5702** <dd>This parameter returns the number of bytes of scratch memory 5703** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 5704** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5705** returned include overflows because the requested allocation was too 5706** larger (that is, because the requested allocation was larger than the 5707** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5708** slots were available. 5709** </dd>)^ 5710** 5711** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5712** <dd>This parameter records the largest memory allocation request 5713** handed to [scratch memory allocator]. Only the value returned in the 5714** *pHighwater parameter to [sqlite3_status()] is of interest. 5715** The value written into the *pCurrent parameter is undefined.</dd>)^ 5716** 5717** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 5718** <dd>This parameter records the deepest parser stack. It is only 5719** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 5720** </dl> 5721** 5722** New status parameters may be added from time to time. 5723*/ 5724#define SQLITE_STATUS_MEMORY_USED 0 5725#define SQLITE_STATUS_PAGECACHE_USED 1 5726#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5727#define SQLITE_STATUS_SCRATCH_USED 3 5728#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5729#define SQLITE_STATUS_MALLOC_SIZE 5 5730#define SQLITE_STATUS_PARSER_STACK 6 5731#define SQLITE_STATUS_PAGECACHE_SIZE 7 5732#define SQLITE_STATUS_SCRATCH_SIZE 8 5733#define SQLITE_STATUS_MALLOC_COUNT 9 5734 5735/* 5736** CAPI3REF: Database Connection Status 5737** 5738** ^This interface is used to retrieve runtime status information 5739** about a single [database connection]. ^The first argument is the 5740** database connection object to be interrogated. ^The second argument 5741** is an integer constant, taken from the set of 5742** [SQLITE_DBSTATUS options], that 5743** determines the parameter to interrogate. The set of 5744** [SQLITE_DBSTATUS options] is likely 5745** to grow in future releases of SQLite. 5746** 5747** ^The current value of the requested parameter is written into *pCur 5748** and the highest instantaneous value is written into *pHiwtr. ^If 5749** the resetFlg is true, then the highest instantaneous value is 5750** reset back down to the current value. 5751** 5752** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 5753** non-zero [error code] on failure. 5754** 5755** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5756*/ 5757SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5758 5759/* 5760** CAPI3REF: Status Parameters for database connections 5761** KEYWORDS: {SQLITE_DBSTATUS options} 5762** 5763** These constants are the available integer "verbs" that can be passed as 5764** the second argument to the [sqlite3_db_status()] interface. 5765** 5766** New verbs may be added in future releases of SQLite. Existing verbs 5767** might be discontinued. Applications should check the return code from 5768** [sqlite3_db_status()] to make sure that the call worked. 5769** The [sqlite3_db_status()] interface will return a non-zero error code 5770** if a discontinued or unsupported verb is invoked. 5771** 5772** <dl> 5773** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5774** <dd>This parameter returns the number of lookaside memory slots currently 5775** checked out.</dd>)^ 5776** 5777** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 5778** <dd>This parameter returns the number malloc attempts that were 5779** satisfied using lookaside memory. Only the high-water value is meaningful; 5780** the current value is always zero.)^ 5781** 5782** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 5783** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 5784** <dd>This parameter returns the number malloc attempts that might have 5785** been satisfied using lookaside memory but failed due to the amount of 5786** memory requested being larger than the lookaside slot size. 5787** Only the high-water value is meaningful; 5788** the current value is always zero.)^ 5789** 5790** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 5791** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 5792** <dd>This parameter returns the number malloc attempts that might have 5793** been satisfied using lookaside memory but failed due to all lookaside 5794** memory already being in use. 5795** Only the high-water value is meaningful; 5796** the current value is always zero.)^ 5797** 5798** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 5799** <dd>This parameter returns the approximate number of of bytes of heap 5800** memory used by all pager caches associated with the database connection.)^ 5801** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 5802** 5803** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 5804** <dd>This parameter returns the approximate number of of bytes of heap 5805** memory used to store the schema for all databases associated 5806** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 5807** ^The full amount of memory used by the schemas is reported, even if the 5808** schema memory is shared with other database connections due to 5809** [shared cache mode] being enabled. 5810** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 5811** 5812** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 5813** <dd>This parameter returns the approximate number of of bytes of heap 5814** and lookaside memory used by all prepared statements associated with 5815** the database connection.)^ 5816** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 5817** </dd> 5818** </dl> 5819*/ 5820#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 5821#define SQLITE_DBSTATUS_CACHE_USED 1 5822#define SQLITE_DBSTATUS_SCHEMA_USED 2 5823#define SQLITE_DBSTATUS_STMT_USED 3 5824#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 5825#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 5826#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 5827#define SQLITE_DBSTATUS_MAX 6 /* Largest defined DBSTATUS */ 5828 5829 5830/* 5831** CAPI3REF: Prepared Statement Status 5832** 5833** ^(Each prepared statement maintains various 5834** [SQLITE_STMTSTATUS counters] that measure the number 5835** of times it has performed specific operations.)^ These counters can 5836** be used to monitor the performance characteristics of the prepared 5837** statements. For example, if the number of table steps greatly exceeds 5838** the number of table searches or result rows, that would tend to indicate 5839** that the prepared statement is using a full table scan rather than 5840** an index. 5841** 5842** ^(This interface is used to retrieve and reset counter values from 5843** a [prepared statement]. The first argument is the prepared statement 5844** object to be interrogated. The second argument 5845** is an integer code for a specific [SQLITE_STMTSTATUS counter] 5846** to be interrogated.)^ 5847** ^The current value of the requested counter is returned. 5848** ^If the resetFlg is true, then the counter is reset to zero after this 5849** interface call returns. 5850** 5851** See also: [sqlite3_status()] and [sqlite3_db_status()]. 5852*/ 5853SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 5854 5855/* 5856** CAPI3REF: Status Parameters for prepared statements 5857** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 5858** 5859** These preprocessor macros define integer codes that name counter 5860** values associated with the [sqlite3_stmt_status()] interface. 5861** The meanings of the various counters are as follows: 5862** 5863** <dl> 5864** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 5865** <dd>^This is the number of times that SQLite has stepped forward in 5866** a table as part of a full table scan. Large numbers for this counter 5867** may indicate opportunities for performance improvement through 5868** careful use of indices.</dd> 5869** 5870** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 5871** <dd>^This is the number of sort operations that have occurred. 5872** A non-zero value in this counter may indicate an opportunity to 5873** improvement performance through careful use of indices.</dd> 5874** 5875** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 5876** <dd>^This is the number of rows inserted into transient indices that 5877** were created automatically in order to help joins run faster. 5878** A non-zero value in this counter may indicate an opportunity to 5879** improvement performance by adding permanent indices that do not 5880** need to be reinitialized each time the statement is run.</dd> 5881** 5882** </dl> 5883*/ 5884#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 5885#define SQLITE_STMTSTATUS_SORT 2 5886#define SQLITE_STMTSTATUS_AUTOINDEX 3 5887 5888/* 5889** CAPI3REF: Custom Page Cache Object 5890** 5891** The sqlite3_pcache type is opaque. It is implemented by 5892** the pluggable module. The SQLite core has no knowledge of 5893** its size or internal structure and never deals with the 5894** sqlite3_pcache object except by holding and passing pointers 5895** to the object. 5896** 5897** See [sqlite3_pcache_methods] for additional information. 5898*/ 5899typedef struct sqlite3_pcache sqlite3_pcache; 5900 5901/* 5902** CAPI3REF: Application Defined Page Cache. 5903** KEYWORDS: {page cache} 5904** 5905** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can 5906** register an alternative page cache implementation by passing in an 5907** instance of the sqlite3_pcache_methods structure.)^ 5908** In many applications, most of the heap memory allocated by 5909** SQLite is used for the page cache. 5910** By implementing a 5911** custom page cache using this API, an application can better control 5912** the amount of memory consumed by SQLite, the way in which 5913** that memory is allocated and released, and the policies used to 5914** determine exactly which parts of a database file are cached and for 5915** how long. 5916** 5917** The alternative page cache mechanism is an 5918** extreme measure that is only needed by the most demanding applications. 5919** The built-in page cache is recommended for most uses. 5920** 5921** ^(The contents of the sqlite3_pcache_methods structure are copied to an 5922** internal buffer by SQLite within the call to [sqlite3_config]. Hence 5923** the application may discard the parameter after the call to 5924** [sqlite3_config()] returns.)^ 5925** 5926** [[the xInit() page cache method]] 5927** ^(The xInit() method is called once for each effective 5928** call to [sqlite3_initialize()])^ 5929** (usually only once during the lifetime of the process). ^(The xInit() 5930** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^ 5931** The intent of the xInit() method is to set up global data structures 5932** required by the custom page cache implementation. 5933** ^(If the xInit() method is NULL, then the 5934** built-in default page cache is used instead of the application defined 5935** page cache.)^ 5936** 5937** [[the xShutdown() page cache method]] 5938** ^The xShutdown() method is called by [sqlite3_shutdown()]. 5939** It can be used to clean up 5940** any outstanding resources before process shutdown, if required. 5941** ^The xShutdown() method may be NULL. 5942** 5943** ^SQLite automatically serializes calls to the xInit method, 5944** so the xInit method need not be threadsafe. ^The 5945** xShutdown method is only called from [sqlite3_shutdown()] so it does 5946** not need to be threadsafe either. All other methods must be threadsafe 5947** in multithreaded applications. 5948** 5949** ^SQLite will never invoke xInit() more than once without an intervening 5950** call to xShutdown(). 5951** 5952** [[the xCreate() page cache methods]] 5953** ^SQLite invokes the xCreate() method to construct a new cache instance. 5954** SQLite will typically create one cache instance for each open database file, 5955** though this is not guaranteed. ^The 5956** first parameter, szPage, is the size in bytes of the pages that must 5957** be allocated by the cache. ^szPage will not be a power of two. ^szPage 5958** will the page size of the database file that is to be cached plus an 5959** increment (here called "R") of less than 250. SQLite will use the 5960** extra R bytes on each page to store metadata about the underlying 5961** database page on disk. The value of R depends 5962** on the SQLite version, the target platform, and how SQLite was compiled. 5963** ^(R is constant for a particular build of SQLite. Except, there are two 5964** distinct values of R when SQLite is compiled with the proprietary 5965** ZIPVFS extension.)^ ^The second argument to 5966** xCreate(), bPurgeable, is true if the cache being created will 5967** be used to cache database pages of a file stored on disk, or 5968** false if it is used for an in-memory database. The cache implementation 5969** does not have to do anything special based with the value of bPurgeable; 5970** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 5971** never invoke xUnpin() except to deliberately delete a page. 5972** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 5973** false will always have the "discard" flag set to true. 5974** ^Hence, a cache created with bPurgeable false will 5975** never contain any unpinned pages. 5976** 5977** [[the xCachesize() page cache method]] 5978** ^(The xCachesize() method may be called at any time by SQLite to set the 5979** suggested maximum cache-size (number of pages stored by) the cache 5980** instance passed as the first argument. This is the value configured using 5981** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 5982** parameter, the implementation is not required to do anything with this 5983** value; it is advisory only. 5984** 5985** [[the xPagecount() page cache methods]] 5986** The xPagecount() method must return the number of pages currently 5987** stored in the cache, both pinned and unpinned. 5988** 5989** [[the xFetch() page cache methods]] 5990** The xFetch() method locates a page in the cache and returns a pointer to 5991** the page, or a NULL pointer. 5992** A "page", in this context, means a buffer of szPage bytes aligned at an 5993** 8-byte boundary. The page to be fetched is determined by the key. ^The 5994** minimum key value is 1. After it has been retrieved using xFetch, the page 5995** is considered to be "pinned". 5996** 5997** If the requested page is already in the page cache, then the page cache 5998** implementation must return a pointer to the page buffer with its content 5999** intact. If the requested page is not already in the cache, then the 6000** cache implementation should use the value of the createFlag 6001** parameter to help it determined what action to take: 6002** 6003** <table border=1 width=85% align=center> 6004** <tr><th> createFlag <th> Behaviour when page is not already in cache 6005** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6006** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6007** Otherwise return NULL. 6008** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6009** NULL if allocating a new page is effectively impossible. 6010** </table> 6011** 6012** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6013** will only use a createFlag of 2 after a prior call with a createFlag of 1 6014** failed.)^ In between the to xFetch() calls, SQLite may 6015** attempt to unpin one or more cache pages by spilling the content of 6016** pinned pages to disk and synching the operating system disk cache. 6017** 6018** [[the xUnpin() page cache method]] 6019** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6020** as its second argument. If the third parameter, discard, is non-zero, 6021** then the page must be evicted from the cache. 6022** ^If the discard parameter is 6023** zero, then the page may be discarded or retained at the discretion of 6024** page cache implementation. ^The page cache implementation 6025** may choose to evict unpinned pages at any time. 6026** 6027** The cache must not perform any reference counting. A single 6028** call to xUnpin() unpins the page regardless of the number of prior calls 6029** to xFetch(). 6030** 6031** [[the xRekey() page cache methods]] 6032** The xRekey() method is used to change the key value associated with the 6033** page passed as the second argument. If the cache 6034** previously contains an entry associated with newKey, it must be 6035** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6036** to be pinned. 6037** 6038** When SQLite calls the xTruncate() method, the cache must discard all 6039** existing cache entries with page numbers (keys) greater than or equal 6040** to the value of the iLimit parameter passed to xTruncate(). If any 6041** of these pages are pinned, they are implicitly unpinned, meaning that 6042** they can be safely discarded. 6043** 6044** [[the xDestroy() page cache method]] 6045** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6046** All resources associated with the specified cache should be freed. ^After 6047** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6048** handle invalid, and will not use it with any other sqlite3_pcache_methods 6049** functions. 6050*/ 6051typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 6052struct sqlite3_pcache_methods { 6053 void *pArg; 6054 int (*xInit)(void*); 6055 void (*xShutdown)(void*); 6056 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 6057 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6058 int (*xPagecount)(sqlite3_pcache*); 6059 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6060 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 6061 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 6062 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6063 void (*xDestroy)(sqlite3_pcache*); 6064}; 6065 6066/* 6067** CAPI3REF: Online Backup Object 6068** 6069** The sqlite3_backup object records state information about an ongoing 6070** online backup operation. ^The sqlite3_backup object is created by 6071** a call to [sqlite3_backup_init()] and is destroyed by a call to 6072** [sqlite3_backup_finish()]. 6073** 6074** See Also: [Using the SQLite Online Backup API] 6075*/ 6076typedef struct sqlite3_backup sqlite3_backup; 6077 6078/* 6079** CAPI3REF: Online Backup API. 6080** 6081** The backup API copies the content of one database into another. 6082** It is useful either for creating backups of databases or 6083** for copying in-memory databases to or from persistent files. 6084** 6085** See Also: [Using the SQLite Online Backup API] 6086** 6087** ^SQLite holds a write transaction open on the destination database file 6088** for the duration of the backup operation. 6089** ^The source database is read-locked only while it is being read; 6090** it is not locked continuously for the entire backup operation. 6091** ^Thus, the backup may be performed on a live source database without 6092** preventing other database connections from 6093** reading or writing to the source database while the backup is underway. 6094** 6095** ^(To perform a backup operation: 6096** <ol> 6097** <li><b>sqlite3_backup_init()</b> is called once to initialize the 6098** backup, 6099** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 6100** the data between the two databases, and finally 6101** <li><b>sqlite3_backup_finish()</b> is called to release all resources 6102** associated with the backup operation. 6103** </ol>)^ 6104** There should be exactly one call to sqlite3_backup_finish() for each 6105** successful call to sqlite3_backup_init(). 6106** 6107** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 6108** 6109** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 6110** [database connection] associated with the destination database 6111** and the database name, respectively. 6112** ^The database name is "main" for the main database, "temp" for the 6113** temporary database, or the name specified after the AS keyword in 6114** an [ATTACH] statement for an attached database. 6115** ^The S and M arguments passed to 6116** sqlite3_backup_init(D,N,S,M) identify the [database connection] 6117** and database name of the source database, respectively. 6118** ^The source and destination [database connections] (parameters S and D) 6119** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 6120** an error. 6121** 6122** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 6123** returned and an error code and error message are stored in the 6124** destination [database connection] D. 6125** ^The error code and message for the failed call to sqlite3_backup_init() 6126** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 6127** [sqlite3_errmsg16()] functions. 6128** ^A successful call to sqlite3_backup_init() returns a pointer to an 6129** [sqlite3_backup] object. 6130** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 6131** sqlite3_backup_finish() functions to perform the specified backup 6132** operation. 6133** 6134** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 6135** 6136** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 6137** the source and destination databases specified by [sqlite3_backup] object B. 6138** ^If N is negative, all remaining source pages are copied. 6139** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 6140** are still more pages to be copied, then the function returns [SQLITE_OK]. 6141** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 6142** from source to destination, then it returns [SQLITE_DONE]. 6143** ^If an error occurs while running sqlite3_backup_step(B,N), 6144** then an [error code] is returned. ^As well as [SQLITE_OK] and 6145** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 6146** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 6147** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 6148** 6149** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 6150** <ol> 6151** <li> the destination database was opened read-only, or 6152** <li> the destination database is using write-ahead-log journaling 6153** and the destination and source page sizes differ, or 6154** <li> the destination database is an in-memory database and the 6155** destination and source page sizes differ. 6156** </ol>)^ 6157** 6158** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 6159** the [sqlite3_busy_handler | busy-handler function] 6160** is invoked (if one is specified). ^If the 6161** busy-handler returns non-zero before the lock is available, then 6162** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 6163** sqlite3_backup_step() can be retried later. ^If the source 6164** [database connection] 6165** is being used to write to the source database when sqlite3_backup_step() 6166** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 6167** case the call to sqlite3_backup_step() can be retried later on. ^(If 6168** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 6169** [SQLITE_READONLY] is returned, then 6170** there is no point in retrying the call to sqlite3_backup_step(). These 6171** errors are considered fatal.)^ The application must accept 6172** that the backup operation has failed and pass the backup operation handle 6173** to the sqlite3_backup_finish() to release associated resources. 6174** 6175** ^The first call to sqlite3_backup_step() obtains an exclusive lock 6176** on the destination file. ^The exclusive lock is not released until either 6177** sqlite3_backup_finish() is called or the backup operation is complete 6178** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 6179** sqlite3_backup_step() obtains a [shared lock] on the source database that 6180** lasts for the duration of the sqlite3_backup_step() call. 6181** ^Because the source database is not locked between calls to 6182** sqlite3_backup_step(), the source database may be modified mid-way 6183** through the backup process. ^If the source database is modified by an 6184** external process or via a database connection other than the one being 6185** used by the backup operation, then the backup will be automatically 6186** restarted by the next call to sqlite3_backup_step(). ^If the source 6187** database is modified by the using the same database connection as is used 6188** by the backup operation, then the backup database is automatically 6189** updated at the same time. 6190** 6191** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 6192** 6193** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 6194** application wishes to abandon the backup operation, the application 6195** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 6196** ^The sqlite3_backup_finish() interfaces releases all 6197** resources associated with the [sqlite3_backup] object. 6198** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 6199** active write-transaction on the destination database is rolled back. 6200** The [sqlite3_backup] object is invalid 6201** and may not be used following a call to sqlite3_backup_finish(). 6202** 6203** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 6204** sqlite3_backup_step() errors occurred, regardless or whether or not 6205** sqlite3_backup_step() completed. 6206** ^If an out-of-memory condition or IO error occurred during any prior 6207** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 6208** sqlite3_backup_finish() returns the corresponding [error code]. 6209** 6210** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 6211** is not a permanent error and does not affect the return value of 6212** sqlite3_backup_finish(). 6213** 6214** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]] 6215** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 6216** 6217** ^Each call to sqlite3_backup_step() sets two values inside 6218** the [sqlite3_backup] object: the number of pages still to be backed 6219** up and the total number of pages in the source database file. 6220** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 6221** retrieve these two values, respectively. 6222** 6223** ^The values returned by these functions are only updated by 6224** sqlite3_backup_step(). ^If the source database is modified during a backup 6225** operation, then the values are not updated to account for any extra 6226** pages that need to be updated or the size of the source database file 6227** changing. 6228** 6229** <b>Concurrent Usage of Database Handles</b> 6230** 6231** ^The source [database connection] may be used by the application for other 6232** purposes while a backup operation is underway or being initialized. 6233** ^If SQLite is compiled and configured to support threadsafe database 6234** connections, then the source database connection may be used concurrently 6235** from within other threads. 6236** 6237** However, the application must guarantee that the destination 6238** [database connection] is not passed to any other API (by any thread) after 6239** sqlite3_backup_init() is called and before the corresponding call to 6240** sqlite3_backup_finish(). SQLite does not currently check to see 6241** if the application incorrectly accesses the destination [database connection] 6242** and so no error code is reported, but the operations may malfunction 6243** nevertheless. Use of the destination database connection while a 6244** backup is in progress might also also cause a mutex deadlock. 6245** 6246** If running in [shared cache mode], the application must 6247** guarantee that the shared cache used by the destination database 6248** is not accessed while the backup is running. In practice this means 6249** that the application must guarantee that the disk file being 6250** backed up to is not accessed by any connection within the process, 6251** not just the specific connection that was passed to sqlite3_backup_init(). 6252** 6253** The [sqlite3_backup] object itself is partially threadsafe. Multiple 6254** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 6255** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 6256** APIs are not strictly speaking threadsafe. If they are invoked at the 6257** same time as another thread is invoking sqlite3_backup_step() it is 6258** possible that they return invalid values. 6259*/ 6260SQLITE_API sqlite3_backup *sqlite3_backup_init( 6261 sqlite3 *pDest, /* Destination database handle */ 6262 const char *zDestName, /* Destination database name */ 6263 sqlite3 *pSource, /* Source database handle */ 6264 const char *zSourceName /* Source database name */ 6265); 6266SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage); 6267SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p); 6268SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p); 6269SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p); 6270 6271/* 6272** CAPI3REF: Unlock Notification 6273** 6274** ^When running in shared-cache mode, a database operation may fail with 6275** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 6276** individual tables within the shared-cache cannot be obtained. See 6277** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 6278** ^This API may be used to register a callback that SQLite will invoke 6279** when the connection currently holding the required lock relinquishes it. 6280** ^This API is only available if the library was compiled with the 6281** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 6282** 6283** See Also: [Using the SQLite Unlock Notification Feature]. 6284** 6285** ^Shared-cache locks are released when a database connection concludes 6286** its current transaction, either by committing it or rolling it back. 6287** 6288** ^When a connection (known as the blocked connection) fails to obtain a 6289** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 6290** identity of the database connection (the blocking connection) that 6291** has locked the required resource is stored internally. ^After an 6292** application receives an SQLITE_LOCKED error, it may call the 6293** sqlite3_unlock_notify() method with the blocked connection handle as 6294** the first argument to register for a callback that will be invoked 6295** when the blocking connections current transaction is concluded. ^The 6296** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 6297** call that concludes the blocking connections transaction. 6298** 6299** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 6300** there is a chance that the blocking connection will have already 6301** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 6302** If this happens, then the specified callback is invoked immediately, 6303** from within the call to sqlite3_unlock_notify().)^ 6304** 6305** ^If the blocked connection is attempting to obtain a write-lock on a 6306** shared-cache table, and more than one other connection currently holds 6307** a read-lock on the same table, then SQLite arbitrarily selects one of 6308** the other connections to use as the blocking connection. 6309** 6310** ^(There may be at most one unlock-notify callback registered by a 6311** blocked connection. If sqlite3_unlock_notify() is called when the 6312** blocked connection already has a registered unlock-notify callback, 6313** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 6314** called with a NULL pointer as its second argument, then any existing 6315** unlock-notify callback is canceled. ^The blocked connections 6316** unlock-notify callback may also be canceled by closing the blocked 6317** connection using [sqlite3_close()]. 6318** 6319** The unlock-notify callback is not reentrant. If an application invokes 6320** any sqlite3_xxx API functions from within an unlock-notify callback, a 6321** crash or deadlock may be the result. 6322** 6323** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 6324** returns SQLITE_OK. 6325** 6326** <b>Callback Invocation Details</b> 6327** 6328** When an unlock-notify callback is registered, the application provides a 6329** single void* pointer that is passed to the callback when it is invoked. 6330** However, the signature of the callback function allows SQLite to pass 6331** it an array of void* context pointers. The first argument passed to 6332** an unlock-notify callback is a pointer to an array of void* pointers, 6333** and the second is the number of entries in the array. 6334** 6335** When a blocking connections transaction is concluded, there may be 6336** more than one blocked connection that has registered for an unlock-notify 6337** callback. ^If two or more such blocked connections have specified the 6338** same callback function, then instead of invoking the callback function 6339** multiple times, it is invoked once with the set of void* context pointers 6340** specified by the blocked connections bundled together into an array. 6341** This gives the application an opportunity to prioritize any actions 6342** related to the set of unblocked database connections. 6343** 6344** <b>Deadlock Detection</b> 6345** 6346** Assuming that after registering for an unlock-notify callback a 6347** database waits for the callback to be issued before taking any further 6348** action (a reasonable assumption), then using this API may cause the 6349** application to deadlock. For example, if connection X is waiting for 6350** connection Y's transaction to be concluded, and similarly connection 6351** Y is waiting on connection X's transaction, then neither connection 6352** will proceed and the system may remain deadlocked indefinitely. 6353** 6354** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 6355** detection. ^If a given call to sqlite3_unlock_notify() would put the 6356** system in a deadlocked state, then SQLITE_LOCKED is returned and no 6357** unlock-notify callback is registered. The system is said to be in 6358** a deadlocked state if connection A has registered for an unlock-notify 6359** callback on the conclusion of connection B's transaction, and connection 6360** B has itself registered for an unlock-notify callback when connection 6361** A's transaction is concluded. ^Indirect deadlock is also detected, so 6362** the system is also considered to be deadlocked if connection B has 6363** registered for an unlock-notify callback on the conclusion of connection 6364** C's transaction, where connection C is waiting on connection A. ^Any 6365** number of levels of indirection are allowed. 6366** 6367** <b>The "DROP TABLE" Exception</b> 6368** 6369** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 6370** always appropriate to call sqlite3_unlock_notify(). There is however, 6371** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 6372** SQLite checks if there are any currently executing SELECT statements 6373** that belong to the same connection. If there are, SQLITE_LOCKED is 6374** returned. In this case there is no "blocking connection", so invoking 6375** sqlite3_unlock_notify() results in the unlock-notify callback being 6376** invoked immediately. If the application then re-attempts the "DROP TABLE" 6377** or "DROP INDEX" query, an infinite loop might be the result. 6378** 6379** One way around this problem is to check the extended error code returned 6380** by an sqlite3_step() call. ^(If there is a blocking connection, then the 6381** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 6382** the special "DROP TABLE/INDEX" case, the extended error code is just 6383** SQLITE_LOCKED.)^ 6384*/ 6385SQLITE_API int sqlite3_unlock_notify( 6386 sqlite3 *pBlocked, /* Waiting connection */ 6387 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 6388 void *pNotifyArg /* Argument to pass to xNotify */ 6389); 6390 6391 6392/* 6393** CAPI3REF: String Comparison 6394** 6395** ^The [sqlite3_strnicmp()] API allows applications and extensions to 6396** compare the contents of two buffers containing UTF-8 strings in a 6397** case-independent fashion, using the same definition of case independence 6398** that SQLite uses internally when comparing identifiers. 6399*/ 6400SQLITE_API int sqlite3_strnicmp(const char *, const char *, int); 6401 6402/* 6403** CAPI3REF: Error Logging Interface 6404** 6405** ^The [sqlite3_log()] interface writes a message into the error log 6406** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 6407** ^If logging is enabled, the zFormat string and subsequent arguments are 6408** used with [sqlite3_snprintf()] to generate the final output string. 6409** 6410** The sqlite3_log() interface is intended for use by extensions such as 6411** virtual tables, collating functions, and SQL functions. While there is 6412** nothing to prevent an application from calling sqlite3_log(), doing so 6413** is considered bad form. 6414** 6415** The zFormat string must not be NULL. 6416** 6417** To avoid deadlocks and other threading problems, the sqlite3_log() routine 6418** will not use dynamically allocated memory. The log message is stored in 6419** a fixed-length buffer on the stack. If the log message is longer than 6420** a few hundred characters, it will be truncated to the length of the 6421** buffer. 6422*/ 6423SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...); 6424 6425/* 6426** CAPI3REF: Write-Ahead Log Commit Hook 6427** 6428** ^The [sqlite3_wal_hook()] function is used to register a callback that 6429** will be invoked each time a database connection commits data to a 6430** [write-ahead log] (i.e. whenever a transaction is committed in 6431** [journal_mode | journal_mode=WAL mode]). 6432** 6433** ^The callback is invoked by SQLite after the commit has taken place and 6434** the associated write-lock on the database released, so the implementation 6435** may read, write or [checkpoint] the database as required. 6436** 6437** ^The first parameter passed to the callback function when it is invoked 6438** is a copy of the third parameter passed to sqlite3_wal_hook() when 6439** registering the callback. ^The second is a copy of the database handle. 6440** ^The third parameter is the name of the database that was written to - 6441** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 6442** is the number of pages currently in the write-ahead log file, 6443** including those that were just committed. 6444** 6445** The callback function should normally return [SQLITE_OK]. ^If an error 6446** code is returned, that error will propagate back up through the 6447** SQLite code base to cause the statement that provoked the callback 6448** to report an error, though the commit will have still occurred. If the 6449** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 6450** that does not correspond to any valid SQLite error code, the results 6451** are undefined. 6452** 6453** A single database handle may have at most a single write-ahead log callback 6454** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 6455** previously registered write-ahead log callback. ^Note that the 6456** [sqlite3_wal_autocheckpoint()] interface and the 6457** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 6458** those overwrite any prior [sqlite3_wal_hook()] settings. 6459*/ 6460SQLITE_API void *sqlite3_wal_hook( 6461 sqlite3*, 6462 int(*)(void *,sqlite3*,const char*,int), 6463 void* 6464); 6465 6466/* 6467** CAPI3REF: Configure an auto-checkpoint 6468** 6469** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 6470** [sqlite3_wal_hook()] that causes any database on [database connection] D 6471** to automatically [checkpoint] 6472** after committing a transaction if there are N or 6473** more frames in the [write-ahead log] file. ^Passing zero or 6474** a negative value as the nFrame parameter disables automatic 6475** checkpoints entirely. 6476** 6477** ^The callback registered by this function replaces any existing callback 6478** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 6479** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 6480** configured by this function. 6481** 6482** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 6483** from SQL. 6484** 6485** ^Every new [database connection] defaults to having the auto-checkpoint 6486** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 6487** pages. The use of this interface 6488** is only necessary if the default setting is found to be suboptimal 6489** for a particular application. 6490*/ 6491SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 6492 6493/* 6494** CAPI3REF: Checkpoint a database 6495** 6496** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 6497** on [database connection] D to be [checkpointed]. ^If X is NULL or an 6498** empty string, then a checkpoint is run on all databases of 6499** connection D. ^If the database connection D is not in 6500** [WAL | write-ahead log mode] then this interface is a harmless no-op. 6501** 6502** ^The [wal_checkpoint pragma] can be used to invoke this interface 6503** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 6504** [wal_autocheckpoint pragma] can be used to cause this interface to be 6505** run whenever the WAL reaches a certain size threshold. 6506** 6507** See also: [sqlite3_wal_checkpoint_v2()] 6508*/ 6509SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 6510 6511/* 6512** CAPI3REF: Checkpoint a database 6513** 6514** Run a checkpoint operation on WAL database zDb attached to database 6515** handle db. The specific operation is determined by the value of the 6516** eMode parameter: 6517** 6518** <dl> 6519** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 6520** Checkpoint as many frames as possible without waiting for any database 6521** readers or writers to finish. Sync the db file if all frames in the log 6522** are checkpointed. This mode is the same as calling 6523** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked. 6524** 6525** <dt>SQLITE_CHECKPOINT_FULL<dd> 6526** This mode blocks (calls the busy-handler callback) until there is no 6527** database writer and all readers are reading from the most recent database 6528** snapshot. It then checkpoints all frames in the log file and syncs the 6529** database file. This call blocks database writers while it is running, 6530** but not database readers. 6531** 6532** <dt>SQLITE_CHECKPOINT_RESTART<dd> 6533** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after 6534** checkpointing the log file it blocks (calls the busy-handler callback) 6535** until all readers are reading from the database file only. This ensures 6536** that the next client to write to the database file restarts the log file 6537** from the beginning. This call blocks database writers while it is running, 6538** but not database readers. 6539** </dl> 6540** 6541** If pnLog is not NULL, then *pnLog is set to the total number of frames in 6542** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to 6543** the total number of checkpointed frames (including any that were already 6544** checkpointed when this function is called). *pnLog and *pnCkpt may be 6545** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK. 6546** If no values are available because of an error, they are both set to -1 6547** before returning to communicate this to the caller. 6548** 6549** All calls obtain an exclusive "checkpoint" lock on the database file. If 6550** any other process is running a checkpoint operation at the same time, the 6551** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a 6552** busy-handler configured, it will not be invoked in this case. 6553** 6554** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive 6555** "writer" lock on the database file. If the writer lock cannot be obtained 6556** immediately, and a busy-handler is configured, it is invoked and the writer 6557** lock retried until either the busy-handler returns 0 or the lock is 6558** successfully obtained. The busy-handler is also invoked while waiting for 6559** database readers as described above. If the busy-handler returns 0 before 6560** the writer lock is obtained or while waiting for database readers, the 6561** checkpoint operation proceeds from that point in the same way as 6562** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 6563** without blocking any further. SQLITE_BUSY is returned in this case. 6564** 6565** If parameter zDb is NULL or points to a zero length string, then the 6566** specified operation is attempted on all WAL databases. In this case the 6567** values written to output parameters *pnLog and *pnCkpt are undefined. If 6568** an SQLITE_BUSY error is encountered when processing one or more of the 6569** attached WAL databases, the operation is still attempted on any remaining 6570** attached databases and SQLITE_BUSY is returned to the caller. If any other 6571** error occurs while processing an attached database, processing is abandoned 6572** and the error code returned to the caller immediately. If no error 6573** (SQLITE_BUSY or otherwise) is encountered while processing the attached 6574** databases, SQLITE_OK is returned. 6575** 6576** If database zDb is the name of an attached database that is not in WAL 6577** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If 6578** zDb is not NULL (or a zero length string) and is not the name of any 6579** attached database, SQLITE_ERROR is returned to the caller. 6580*/ 6581SQLITE_API int sqlite3_wal_checkpoint_v2( 6582 sqlite3 *db, /* Database handle */ 6583 const char *zDb, /* Name of attached database (or NULL) */ 6584 int eMode, /* SQLITE_CHECKPOINT_* value */ 6585 int *pnLog, /* OUT: Size of WAL log in frames */ 6586 int *pnCkpt /* OUT: Total number of frames checkpointed */ 6587); 6588 6589/* 6590** CAPI3REF: Checkpoint operation parameters 6591** 6592** These constants can be used as the 3rd parameter to 6593** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()] 6594** documentation for additional information about the meaning and use of 6595** each of these values. 6596*/ 6597#define SQLITE_CHECKPOINT_PASSIVE 0 6598#define SQLITE_CHECKPOINT_FULL 1 6599#define SQLITE_CHECKPOINT_RESTART 2 6600 6601/* 6602** CAPI3REF: Virtual Table Interface Configuration 6603** 6604** This function may be called by either the [xConnect] or [xCreate] method 6605** of a [virtual table] implementation to configure 6606** various facets of the virtual table interface. 6607** 6608** If this interface is invoked outside the context of an xConnect or 6609** xCreate virtual table method then the behavior is undefined. 6610** 6611** At present, there is only one option that may be configured using 6612** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 6613** may be added in the future. 6614*/ 6615SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...); 6616 6617/* 6618** CAPI3REF: Virtual Table Configuration Options 6619** 6620** These macros define the various options to the 6621** [sqlite3_vtab_config()] interface that [virtual table] implementations 6622** can use to customize and optimize their behavior. 6623** 6624** <dl> 6625** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 6626** <dd>Calls of the form 6627** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 6628** where X is an integer. If X is zero, then the [virtual table] whose 6629** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 6630** support constraints. In this configuration (which is the default) if 6631** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 6632** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 6633** specified as part of the users SQL statement, regardless of the actual 6634** ON CONFLICT mode specified. 6635** 6636** If X is non-zero, then the virtual table implementation guarantees 6637** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 6638** any modifications to internal or persistent data structures have been made. 6639** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 6640** is able to roll back a statement or database transaction, and abandon 6641** or continue processing the current SQL statement as appropriate. 6642** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 6643** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 6644** had been ABORT. 6645** 6646** Virtual table implementations that are required to handle OR REPLACE 6647** must do so within the [xUpdate] method. If a call to the 6648** [sqlite3_vtab_on_conflict()] function indicates that the current ON 6649** CONFLICT policy is REPLACE, the virtual table implementation should 6650** silently replace the appropriate rows within the xUpdate callback and 6651** return SQLITE_OK. Or, if this is not possible, it may return 6652** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 6653** constraint handling. 6654** </dl> 6655*/ 6656#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 6657 6658/* 6659** CAPI3REF: Determine The Virtual Table Conflict Policy 6660** 6661** This function may only be called from within a call to the [xUpdate] method 6662** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 6663** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 6664** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 6665** of the SQL statement that triggered the call to the [xUpdate] method of the 6666** [virtual table]. 6667*/ 6668SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *); 6669 6670/* 6671** CAPI3REF: Conflict resolution modes 6672** 6673** These constants are returned by [sqlite3_vtab_on_conflict()] to 6674** inform a [virtual table] implementation what the [ON CONFLICT] mode 6675** is for the SQL statement being evaluated. 6676** 6677** Note that the [SQLITE_IGNORE] constant is also used as a potential 6678** return value from the [sqlite3_set_authorizer()] callback and that 6679** [SQLITE_ABORT] is also a [result code]. 6680*/ 6681#define SQLITE_ROLLBACK 1 6682/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 6683#define SQLITE_FAIL 3 6684/* #define SQLITE_ABORT 4 // Also an error code */ 6685#define SQLITE_REPLACE 5 6686 6687 6688 6689/* 6690** Undo the hack that converts floating point types to integer for 6691** builds on processors without floating point support. 6692*/ 6693#ifdef SQLITE_OMIT_FLOATING_POINT 6694# undef double 6695#endif 6696 6697#ifdef __cplusplus 6698} /* End of the 'extern "C"' block */ 6699#endif 6700#endif 6701 6702/* 6703** 2010 August 30 6704** 6705** The author disclaims copyright to this source code. In place of 6706** a legal notice, here is a blessing: 6707** 6708** May you do good and not evil. 6709** May you find forgiveness for yourself and forgive others. 6710** May you share freely, never taking more than you give. 6711** 6712************************************************************************* 6713*/ 6714 6715#ifndef _SQLITE3RTREE_H_ 6716#define _SQLITE3RTREE_H_ 6717 6718 6719#ifdef __cplusplus 6720extern "C" { 6721#endif 6722 6723typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry; 6724 6725/* 6726** Register a geometry callback named zGeom that can be used as part of an 6727** R-Tree geometry query as follows: 6728** 6729** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...) 6730*/ 6731SQLITE_API int sqlite3_rtree_geometry_callback( 6732 sqlite3 *db, 6733 const char *zGeom, 6734 int (*xGeom)(sqlite3_rtree_geometry *, int nCoord, double *aCoord, int *pRes), 6735 void *pContext 6736); 6737 6738 6739/* 6740** A pointer to a structure of the following type is passed as the first 6741** argument to callbacks registered using rtree_geometry_callback(). 6742*/ 6743struct sqlite3_rtree_geometry { 6744 void *pContext; /* Copy of pContext passed to s_r_g_c() */ 6745 int nParam; /* Size of array aParam[] */ 6746 double *aParam; /* Parameters passed to SQL geom function */ 6747 void *pUser; /* Callback implementation user data */ 6748 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */ 6749}; 6750 6751 6752#ifdef __cplusplus 6753} /* end of the 'extern "C"' block */ 6754#endif 6755 6756#endif /* ifndef _SQLITE3RTREE_H_ */ 6757 6758