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 to make minor changes if 22** 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** @(#) $Id: sqlite.h.in,v 1.459 2009/07/15 11:26:44 drh Exp $ 34*/ 35#ifndef _SQLITE3_H_ 36#define _SQLITE3_H_ 37#include <stdarg.h> /* Needed for the definition of va_list */ 38 39/* 40** Make sure we can call this stuff from C++. 41*/ 42#ifdef __cplusplus 43extern "C" { 44#endif 45 46 47/* 48** Add the ability to override 'extern' 49*/ 50#ifndef SQLITE_EXTERN 51# define SQLITE_EXTERN extern 52#endif 53 54/* 55** These no-op macros are used in front of interfaces to mark those 56** interfaces as either deprecated or experimental. New applications 57** should not use deprecated intrfaces - they are support for backwards 58** compatibility only. Application writers should be aware that 59** experimental interfaces are subject to change in point releases. 60** 61** These macros used to resolve to various kinds of compiler magic that 62** would generate warning messages when they were used. But that 63** compiler magic ended up generating such a flurry of bug reports 64** that we have taken it all out and gone back to using simple 65** noop macros. 66*/ 67#define SQLITE_DEPRECATED 68#define SQLITE_EXPERIMENTAL 69 70/* 71** Ensure these symbols were not defined by some previous header file. 72*/ 73#ifdef SQLITE_VERSION 74# undef SQLITE_VERSION 75#endif 76#ifdef SQLITE_VERSION_NUMBER 77# undef SQLITE_VERSION_NUMBER 78#endif 79 80/* 81** CAPI3REF: Compile-Time Library Version Numbers {H10010} <S60100> 82** 83** The SQLITE_VERSION and SQLITE_VERSION_NUMBER #defines in 84** the sqlite3.h file specify the version of SQLite with which 85** that header file is associated. 86** 87** The "version" of SQLite is a string of the form "X.Y.Z". 88** The phrase "alpha" or "beta" might be appended after the Z. 89** The X value is major version number always 3 in SQLite3. 90** The X value only changes when backwards compatibility is 91** broken and we intend to never break backwards compatibility. 92** The Y value is the minor version number and only changes when 93** there are major feature enhancements that are forwards compatible 94** but not backwards compatible. 95** The Z value is the release number and is incremented with 96** each release but resets back to 0 whenever Y is incremented. 97** 98** See also: [sqlite3_libversion()] and [sqlite3_libversion_number()]. 99** 100** Requirements: [H10011] [H10014] 101*/ 102#define SQLITE_VERSION "--VERS--" 103#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 104 105/* 106** CAPI3REF: Run-Time Library Version Numbers {H10020} <S60100> 107** KEYWORDS: sqlite3_version 108** 109** These features provide the same information as the [SQLITE_VERSION] 110** and [SQLITE_VERSION_NUMBER] #defines in the header, but are associated 111** with the library instead of the header file. Cautious programmers might 112** include a check in their application to verify that 113** sqlite3_libversion_number() always returns the value 114** [SQLITE_VERSION_NUMBER]. 115** 116** The sqlite3_libversion() function returns the same information as is 117** in the sqlite3_version[] string constant. The function is provided 118** for use in DLLs since DLL users usually do not have direct access to string 119** constants within the DLL. 120** 121** Requirements: [H10021] [H10022] [H10023] 122*/ 123SQLITE_EXTERN const char sqlite3_version[]; 124const char *sqlite3_libversion(void); 125int sqlite3_libversion_number(void); 126 127/* 128** CAPI3REF: Test To See If The Library Is Threadsafe {H10100} <S60100> 129** 130** SQLite can be compiled with or without mutexes. When 131** the [SQLITE_THREADSAFE] C preprocessor macro 1 or 2, mutexes 132** are enabled and SQLite is threadsafe. When the 133** [SQLITE_THREADSAFE] macro is 0, 134** the mutexes are omitted. Without the mutexes, it is not safe 135** to use SQLite concurrently from more than one thread. 136** 137** Enabling mutexes incurs a measurable performance penalty. 138** So if speed is of utmost importance, it makes sense to disable 139** the mutexes. But for maximum safety, mutexes should be enabled. 140** The default behavior is for mutexes to be enabled. 141** 142** This interface can be used by a program to make sure that the 143** version of SQLite that it is linking against was compiled with 144** the desired setting of the [SQLITE_THREADSAFE] macro. 145** 146** This interface only reports on the compile-time mutex setting 147** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 148** SQLITE_THREADSAFE=1 then mutexes are enabled by default but 149** can be fully or partially disabled using a call to [sqlite3_config()] 150** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 151** or [SQLITE_CONFIG_MUTEX]. The return value of this function shows 152** only the default compile-time setting, not any run-time changes 153** to that setting. 154** 155** See the [threading mode] documentation for additional information. 156** 157** Requirements: [H10101] [H10102] 158*/ 159int sqlite3_threadsafe(void); 160 161/* 162** CAPI3REF: Database Connection Handle {H12000} <S40200> 163** KEYWORDS: {database connection} {database connections} 164** 165** Each open SQLite database is represented by a pointer to an instance of 166** the opaque structure named "sqlite3". It is useful to think of an sqlite3 167** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 168** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 169** is its destructor. There are many other interfaces (such as 170** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 171** [sqlite3_busy_timeout()] to name but three) that are methods on an 172** sqlite3 object. 173*/ 174typedef struct sqlite3 sqlite3; 175 176/* 177** CAPI3REF: 64-Bit Integer Types {H10200} <S10110> 178** KEYWORDS: sqlite_int64 sqlite_uint64 179** 180** Because there is no cross-platform way to specify 64-bit integer types 181** SQLite includes typedefs for 64-bit signed and unsigned integers. 182** 183** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 184** The sqlite_int64 and sqlite_uint64 types are supported for backwards 185** compatibility only. 186** 187** Requirements: [H10201] [H10202] 188*/ 189#ifdef SQLITE_INT64_TYPE 190 typedef SQLITE_INT64_TYPE sqlite_int64; 191 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 192#elif defined(_MSC_VER) || defined(__BORLANDC__) 193 typedef __int64 sqlite_int64; 194 typedef unsigned __int64 sqlite_uint64; 195#else 196 typedef long long int sqlite_int64; 197 typedef unsigned long long int sqlite_uint64; 198#endif 199typedef sqlite_int64 sqlite3_int64; 200typedef sqlite_uint64 sqlite3_uint64; 201 202/* 203** If compiling for a processor that lacks floating point support, 204** substitute integer for floating-point. 205*/ 206#ifdef SQLITE_OMIT_FLOATING_POINT 207# define double sqlite3_int64 208#endif 209 210/* 211** CAPI3REF: Closing A Database Connection {H12010} <S30100><S40200> 212** 213** This routine is the destructor for the [sqlite3] object. 214** 215** Applications should [sqlite3_finalize | finalize] all [prepared statements] 216** and [sqlite3_blob_close | close] all [BLOB handles] associated with 217** the [sqlite3] object prior to attempting to close the object. 218** The [sqlite3_next_stmt()] interface can be used to locate all 219** [prepared statements] associated with a [database connection] if desired. 220** Typical code might look like this: 221** 222** <blockquote><pre> 223** sqlite3_stmt *pStmt; 224** while( (pStmt = sqlite3_next_stmt(db, 0))!=0 ){ 225** sqlite3_finalize(pStmt); 226** } 227** </pre></blockquote> 228** 229** If [sqlite3_close()] is invoked while a transaction is open, 230** the transaction is automatically rolled back. 231** 232** The C parameter to [sqlite3_close(C)] must be either a NULL 233** pointer or an [sqlite3] object pointer obtained 234** from [sqlite3_open()], [sqlite3_open16()], or 235** [sqlite3_open_v2()], and not previously closed. 236** 237** Requirements: 238** [H12011] [H12012] [H12013] [H12014] [H12015] [H12019] 239*/ 240int sqlite3_close(sqlite3 *); 241 242/* 243** The type for a callback function. 244** This is legacy and deprecated. It is included for historical 245** compatibility and is not documented. 246*/ 247typedef int (*sqlite3_callback)(void*,int,char**, char**); 248 249/* 250** CAPI3REF: One-Step Query Execution Interface {H12100} <S10000> 251** 252** The sqlite3_exec() interface is a convenient way of running one or more 253** SQL statements without having to write a lot of C code. The UTF-8 encoded 254** SQL statements are passed in as the second parameter to sqlite3_exec(). 255** The statements are evaluated one by one until either an error or 256** an interrupt is encountered, or until they are all done. The 3rd parameter 257** is an optional callback that is invoked once for each row of any query 258** results produced by the SQL statements. The 5th parameter tells where 259** to write any error messages. 260** 261** The error message passed back through the 5th parameter is held 262** in memory obtained from [sqlite3_malloc()]. To avoid a memory leak, 263** the calling application should call [sqlite3_free()] on any error 264** message returned through the 5th parameter when it has finished using 265** the error message. 266** 267** If the SQL statement in the 2nd parameter is NULL or an empty string 268** or a string containing only whitespace and comments, then no SQL 269** statements are evaluated and the database is not changed. 270** 271** The sqlite3_exec() interface is implemented in terms of 272** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()]. 273** The sqlite3_exec() routine does nothing to the database that cannot be done 274** by [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()]. 275** 276** The first parameter to [sqlite3_exec()] must be an valid and open 277** [database connection]. 278** 279** The database connection must not be closed while 280** [sqlite3_exec()] is running. 281** 282** The calling function should use [sqlite3_free()] to free 283** the memory that *errmsg is left pointing at once the error 284** message is no longer needed. 285** 286** The SQL statement text in the 2nd parameter to [sqlite3_exec()] 287** must remain unchanged while [sqlite3_exec()] is running. 288** 289** Requirements: 290** [H12101] [H12102] [H12104] [H12105] [H12107] [H12110] [H12113] [H12116] 291** [H12119] [H12122] [H12125] [H12131] [H12134] [H12137] [H12138] 292*/ 293int sqlite3_exec( 294 sqlite3*, /* An open database */ 295 const char *sql, /* SQL to be evaluated */ 296 int (*callback)(void*,int,char**,char**), /* Callback function */ 297 void *, /* 1st argument to callback */ 298 char **errmsg /* Error msg written here */ 299); 300 301/* 302** CAPI3REF: Result Codes {H10210} <S10700> 303** KEYWORDS: SQLITE_OK {error code} {error codes} 304** KEYWORDS: {result code} {result codes} 305** 306** Many SQLite functions return an integer result code from the set shown 307** here in order to indicates success or failure. 308** 309** New error codes may be added in future versions of SQLite. 310** 311** See also: [SQLITE_IOERR_READ | extended result codes] 312*/ 313#define SQLITE_OK 0 /* Successful result */ 314/* beginning-of-error-codes */ 315#define SQLITE_ERROR 1 /* SQL error or missing database */ 316#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 317#define SQLITE_PERM 3 /* Access permission denied */ 318#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 319#define SQLITE_BUSY 5 /* The database file is locked */ 320#define SQLITE_LOCKED 6 /* A table in the database is locked */ 321#define SQLITE_NOMEM 7 /* A malloc() failed */ 322#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 323#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 324#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 325#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 326#define SQLITE_NOTFOUND 12 /* NOT USED. Table or record not found */ 327#define SQLITE_FULL 13 /* Insertion failed because database is full */ 328#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 329#define SQLITE_PROTOCOL 15 /* NOT USED. Database lock protocol error */ 330#define SQLITE_EMPTY 16 /* Database is empty */ 331#define SQLITE_SCHEMA 17 /* The database schema changed */ 332#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 333#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 334#define SQLITE_MISMATCH 20 /* Data type mismatch */ 335#define SQLITE_MISUSE 21 /* Library used incorrectly */ 336#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 337#define SQLITE_AUTH 23 /* Authorization denied */ 338#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 339#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 340#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 341#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 342#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 343/* end-of-error-codes */ 344 345/* 346** CAPI3REF: Extended Result Codes {H10220} <S10700> 347** KEYWORDS: {extended error code} {extended error codes} 348** KEYWORDS: {extended result code} {extended result codes} 349** 350** In its default configuration, SQLite API routines return one of 26 integer 351** [SQLITE_OK | result codes]. However, experience has shown that many of 352** these result codes are too coarse-grained. They do not provide as 353** much information about problems as programmers might like. In an effort to 354** address this, newer versions of SQLite (version 3.3.8 and later) include 355** support for additional result codes that provide more detailed information 356** about errors. The extended result codes are enabled or disabled 357** on a per database connection basis using the 358** [sqlite3_extended_result_codes()] API. 359** 360** Some of the available extended result codes are listed here. 361** One may expect the number of extended result codes will be expand 362** over time. Software that uses extended result codes should expect 363** to see new result codes in future releases of SQLite. 364** 365** The SQLITE_OK result code will never be extended. It will always 366** be exactly zero. 367*/ 368#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 369#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 370#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 371#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 372#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 373#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 374#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 375#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 376#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 377#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 378#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 379#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 380#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 381#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 382#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 383#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 384#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 385#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8) ) 386 387/* 388** CAPI3REF: Flags For File Open Operations {H10230} <H11120> <H12700> 389** 390** These bit values are intended for use in the 391** 3rd parameter to the [sqlite3_open_v2()] interface and 392** in the 4th parameter to the xOpen method of the 393** [sqlite3_vfs] object. 394*/ 395#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 396#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 397#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 398#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 399#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 400#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 401#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 402#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 403#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 404#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 405#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 406#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 407#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 408#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 409 410/* 411** CAPI3REF: Device Characteristics {H10240} <H11120> 412** 413** The xDeviceCapabilities method of the [sqlite3_io_methods] 414** object returns an integer which is a vector of the these 415** bit values expressing I/O characteristics of the mass storage 416** device that holds the file that the [sqlite3_io_methods] 417** refers to. 418** 419** The SQLITE_IOCAP_ATOMIC property means that all writes of 420** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 421** mean that writes of blocks that are nnn bytes in size and 422** are aligned to an address which is an integer multiple of 423** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 424** that when data is appended to a file, the data is appended 425** first then the size of the file is extended, never the other 426** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 427** information is written to disk in the same order as calls 428** to xWrite(). 429*/ 430#define SQLITE_IOCAP_ATOMIC 0x00000001 431#define SQLITE_IOCAP_ATOMIC512 0x00000002 432#define SQLITE_IOCAP_ATOMIC1K 0x00000004 433#define SQLITE_IOCAP_ATOMIC2K 0x00000008 434#define SQLITE_IOCAP_ATOMIC4K 0x00000010 435#define SQLITE_IOCAP_ATOMIC8K 0x00000020 436#define SQLITE_IOCAP_ATOMIC16K 0x00000040 437#define SQLITE_IOCAP_ATOMIC32K 0x00000080 438#define SQLITE_IOCAP_ATOMIC64K 0x00000100 439#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 440#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 441 442/* 443** CAPI3REF: File Locking Levels {H10250} <H11120> <H11310> 444** 445** SQLite uses one of these integer values as the second 446** argument to calls it makes to the xLock() and xUnlock() methods 447** of an [sqlite3_io_methods] object. 448*/ 449#define SQLITE_LOCK_NONE 0 450#define SQLITE_LOCK_SHARED 1 451#define SQLITE_LOCK_RESERVED 2 452#define SQLITE_LOCK_PENDING 3 453#define SQLITE_LOCK_EXCLUSIVE 4 454 455/* 456** CAPI3REF: Synchronization Type Flags {H10260} <H11120> 457** 458** When SQLite invokes the xSync() method of an 459** [sqlite3_io_methods] object it uses a combination of 460** these integer values as the second argument. 461** 462** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 463** sync operation only needs to flush data to mass storage. Inode 464** information need not be flushed. If the lower four bits of the flag 465** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 466** If the lower four bits equal SQLITE_SYNC_FULL, that means 467** to use Mac OS X style fullsync instead of fsync(). 468*/ 469#define SQLITE_SYNC_NORMAL 0x00002 470#define SQLITE_SYNC_FULL 0x00003 471#define SQLITE_SYNC_DATAONLY 0x00010 472 473/* 474** CAPI3REF: OS Interface Open File Handle {H11110} <S20110> 475** 476** An [sqlite3_file] object represents an open file in the OS 477** interface layer. Individual OS interface implementations will 478** want to subclass this object by appending additional fields 479** for their own use. The pMethods entry is a pointer to an 480** [sqlite3_io_methods] object that defines methods for performing 481** I/O operations on the open file. 482*/ 483typedef struct sqlite3_file sqlite3_file; 484struct sqlite3_file { 485 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 486}; 487 488/* 489** CAPI3REF: OS Interface File Virtual Methods Object {H11120} <S20110> 490** 491** Every file opened by the [sqlite3_vfs] xOpen method populates an 492** [sqlite3_file] object (or, more commonly, a subclass of the 493** [sqlite3_file] object) with a pointer to an instance of this object. 494** This object defines the methods used to perform various operations 495** against the open file represented by the [sqlite3_file] object. 496** 497** If the xOpen method sets the sqlite3_file.pMethods element 498** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 499** may be invoked even if the xOpen reported that it failed. The 500** only way to prevent a call to xClose following a failed xOpen 501** is for the xOpen to set the sqlite3_file.pMethods element to NULL. 502** 503** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 504** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 505** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 506** flag may be ORed in to indicate that only the data of the file 507** and not its inode needs to be synced. 508** 509** The integer values to xLock() and xUnlock() are one of 510** <ul> 511** <li> [SQLITE_LOCK_NONE], 512** <li> [SQLITE_LOCK_SHARED], 513** <li> [SQLITE_LOCK_RESERVED], 514** <li> [SQLITE_LOCK_PENDING], or 515** <li> [SQLITE_LOCK_EXCLUSIVE]. 516** </ul> 517** xLock() increases the lock. xUnlock() decreases the lock. 518** The xCheckReservedLock() method checks whether any database connection, 519** either in this process or in some other process, is holding a RESERVED, 520** PENDING, or EXCLUSIVE lock on the file. It returns true 521** if such a lock exists and false otherwise. 522** 523** The xFileControl() method is a generic interface that allows custom 524** VFS implementations to directly control an open file using the 525** [sqlite3_file_control()] interface. The second "op" argument is an 526** integer opcode. The third argument is a generic pointer intended to 527** point to a structure that may contain arguments or space in which to 528** write return values. Potential uses for xFileControl() might be 529** functions to enable blocking locks with timeouts, to change the 530** locking strategy (for example to use dot-file locks), to inquire 531** about the status of a lock, or to break stale locks. The SQLite 532** core reserves all opcodes less than 100 for its own use. 533** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 534** Applications that define a custom xFileControl method should use opcodes 535** greater than 100 to avoid conflicts. 536** 537** The xSectorSize() method returns the sector size of the 538** device that underlies the file. The sector size is the 539** minimum write that can be performed without disturbing 540** other bytes in the file. The xDeviceCharacteristics() 541** method returns a bit vector describing behaviors of the 542** underlying device: 543** 544** <ul> 545** <li> [SQLITE_IOCAP_ATOMIC] 546** <li> [SQLITE_IOCAP_ATOMIC512] 547** <li> [SQLITE_IOCAP_ATOMIC1K] 548** <li> [SQLITE_IOCAP_ATOMIC2K] 549** <li> [SQLITE_IOCAP_ATOMIC4K] 550** <li> [SQLITE_IOCAP_ATOMIC8K] 551** <li> [SQLITE_IOCAP_ATOMIC16K] 552** <li> [SQLITE_IOCAP_ATOMIC32K] 553** <li> [SQLITE_IOCAP_ATOMIC64K] 554** <li> [SQLITE_IOCAP_SAFE_APPEND] 555** <li> [SQLITE_IOCAP_SEQUENTIAL] 556** </ul> 557** 558** The SQLITE_IOCAP_ATOMIC property means that all writes of 559** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 560** mean that writes of blocks that are nnn bytes in size and 561** are aligned to an address which is an integer multiple of 562** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 563** that when data is appended to a file, the data is appended 564** first then the size of the file is extended, never the other 565** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 566** information is written to disk in the same order as calls 567** to xWrite(). 568** 569** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 570** in the unread portions of the buffer with zeros. A VFS that 571** fails to zero-fill short reads might seem to work. However, 572** failure to zero-fill short reads will eventually lead to 573** database corruption. 574*/ 575typedef struct sqlite3_io_methods sqlite3_io_methods; 576struct sqlite3_io_methods { 577 int iVersion; 578 int (*xClose)(sqlite3_file*); 579 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 580 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 581 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 582 int (*xSync)(sqlite3_file*, int flags); 583 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 584 int (*xLock)(sqlite3_file*, int); 585 int (*xUnlock)(sqlite3_file*, int); 586 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 587 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 588 int (*xSectorSize)(sqlite3_file*); 589 int (*xDeviceCharacteristics)(sqlite3_file*); 590 /* Additional methods may be added in future releases */ 591}; 592 593/* 594** CAPI3REF: Standard File Control Opcodes {H11310} <S30800> 595** 596** These integer constants are opcodes for the xFileControl method 597** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 598** interface. 599** 600** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 601** opcode causes the xFileControl method to write the current state of 602** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 603** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 604** into an integer that the pArg argument points to. This capability 605** is used during testing and only needs to be supported when SQLITE_TEST 606** is defined. 607*/ 608#define SQLITE_FCNTL_LOCKSTATE 1 609#define SQLITE_GET_LOCKPROXYFILE 2 610#define SQLITE_SET_LOCKPROXYFILE 3 611#define SQLITE_LAST_ERRNO 4 612 613/* 614** CAPI3REF: Mutex Handle {H17110} <S20130> 615** 616** The mutex module within SQLite defines [sqlite3_mutex] to be an 617** abstract type for a mutex object. The SQLite core never looks 618** at the internal representation of an [sqlite3_mutex]. It only 619** deals with pointers to the [sqlite3_mutex] object. 620** 621** Mutexes are created using [sqlite3_mutex_alloc()]. 622*/ 623typedef struct sqlite3_mutex sqlite3_mutex; 624 625/* 626** CAPI3REF: OS Interface Object {H11140} <S20100> 627** 628** An instance of the sqlite3_vfs object defines the interface between 629** the SQLite core and the underlying operating system. The "vfs" 630** in the name of the object stands for "virtual file system". 631** 632** The value of the iVersion field is initially 1 but may be larger in 633** future versions of SQLite. Additional fields may be appended to this 634** object when the iVersion value is increased. Note that the structure 635** of the sqlite3_vfs object changes in the transaction between 636** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 637** modified. 638** 639** The szOsFile field is the size of the subclassed [sqlite3_file] 640** structure used by this VFS. mxPathname is the maximum length of 641** a pathname in this VFS. 642** 643** Registered sqlite3_vfs objects are kept on a linked list formed by 644** the pNext pointer. The [sqlite3_vfs_register()] 645** and [sqlite3_vfs_unregister()] interfaces manage this list 646** in a thread-safe way. The [sqlite3_vfs_find()] interface 647** searches the list. Neither the application code nor the VFS 648** implementation should use the pNext pointer. 649** 650** The pNext field is the only field in the sqlite3_vfs 651** structure that SQLite will ever modify. SQLite will only access 652** or modify this field while holding a particular static mutex. 653** The application should never modify anything within the sqlite3_vfs 654** object once the object has been registered. 655** 656** The zName field holds the name of the VFS module. The name must 657** be unique across all VFS modules. 658** 659** SQLite will guarantee that the zFilename parameter to xOpen 660** is either a NULL pointer or string obtained 661** from xFullPathname(). SQLite further guarantees that 662** the string will be valid and unchanged until xClose() is 663** called. Because of the previous sentence, 664** the [sqlite3_file] can safely store a pointer to the 665** filename if it needs to remember the filename for some reason. 666** If the zFilename parameter is xOpen is a NULL pointer then xOpen 667** must invent its own temporary name for the file. Whenever the 668** xFilename parameter is NULL it will also be the case that the 669** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 670** 671** The flags argument to xOpen() includes all bits set in 672** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 673** or [sqlite3_open16()] is used, then flags includes at least 674** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 675** If xOpen() opens a file read-only then it sets *pOutFlags to 676** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 677** 678** SQLite will also add one of the following flags to the xOpen() 679** call, depending on the object being opened: 680** 681** <ul> 682** <li> [SQLITE_OPEN_MAIN_DB] 683** <li> [SQLITE_OPEN_MAIN_JOURNAL] 684** <li> [SQLITE_OPEN_TEMP_DB] 685** <li> [SQLITE_OPEN_TEMP_JOURNAL] 686** <li> [SQLITE_OPEN_TRANSIENT_DB] 687** <li> [SQLITE_OPEN_SUBJOURNAL] 688** <li> [SQLITE_OPEN_MASTER_JOURNAL] 689** </ul> 690** 691** The file I/O implementation can use the object type flags to 692** change the way it deals with files. For example, an application 693** that does not care about crash recovery or rollback might make 694** the open of a journal file a no-op. Writes to this journal would 695** also be no-ops, and any attempt to read the journal would return 696** SQLITE_IOERR. Or the implementation might recognize that a database 697** file will be doing page-aligned sector reads and writes in a random 698** order and set up its I/O subsystem accordingly. 699** 700** SQLite might also add one of the following flags to the xOpen method: 701** 702** <ul> 703** <li> [SQLITE_OPEN_DELETEONCLOSE] 704** <li> [SQLITE_OPEN_EXCLUSIVE] 705** </ul> 706** 707** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 708** deleted when it is closed. The [SQLITE_OPEN_DELETEONCLOSE] 709** will be set for TEMP databases, journals and for subjournals. 710** 711** The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 712** with the [SQLITE_OPEN_CREATE] flag, which are both directly 713** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 714** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 715** SQLITE_OPEN_CREATE, is used to indicate that file should always 716** be created, and that it is an error if it already exists. 717** It is <i>not</i> used to indicate the file should be opened 718** for exclusive access. 719** 720** At least szOsFile bytes of memory are allocated by SQLite 721** to hold the [sqlite3_file] structure passed as the third 722** argument to xOpen. The xOpen method does not have to 723** allocate the structure; it should just fill it in. Note that 724** the xOpen method must set the sqlite3_file.pMethods to either 725** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 726** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 727** element will be valid after xOpen returns regardless of the success 728** or failure of the xOpen call. 729** 730** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 731** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 732** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 733** to test whether a file is at least readable. The file can be a 734** directory. 735** 736** SQLite will always allocate at least mxPathname+1 bytes for the 737** output buffer xFullPathname. The exact size of the output buffer 738** is also passed as a parameter to both methods. If the output buffer 739** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 740** handled as a fatal error by SQLite, vfs implementations should endeavor 741** to prevent this by setting mxPathname to a sufficiently large value. 742** 743** The xRandomness(), xSleep(), and xCurrentTime() interfaces 744** are not strictly a part of the filesystem, but they are 745** included in the VFS structure for completeness. 746** The xRandomness() function attempts to return nBytes bytes 747** of good-quality randomness into zOut. The return value is 748** the actual number of bytes of randomness obtained. 749** The xSleep() method causes the calling thread to sleep for at 750** least the number of microseconds given. The xCurrentTime() 751** method returns a Julian Day Number for the current date and time. 752** 753*/ 754typedef struct sqlite3_vfs sqlite3_vfs; 755struct sqlite3_vfs { 756 int iVersion; /* Structure version number */ 757 int szOsFile; /* Size of subclassed sqlite3_file */ 758 int mxPathname; /* Maximum file pathname length */ 759 sqlite3_vfs *pNext; /* Next registered VFS */ 760 const char *zName; /* Name of this virtual file system */ 761 void *pAppData; /* Pointer to application-specific data */ 762 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 763 int flags, int *pOutFlags); 764 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 765 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 766 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 767 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 768 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 769 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 770 void (*xDlClose)(sqlite3_vfs*, void*); 771 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 772 int (*xSleep)(sqlite3_vfs*, int microseconds); 773 int (*xCurrentTime)(sqlite3_vfs*, double*); 774 int (*xGetLastError)(sqlite3_vfs*, int, char *); 775 /* New fields may be appended in figure versions. The iVersion 776 ** value will increment whenever this happens. */ 777}; 778 779/* 780** CAPI3REF: Flags for the xAccess VFS method {H11190} <H11140> 781** 782** These integer constants can be used as the third parameter to 783** the xAccess method of an [sqlite3_vfs] object. {END} They determine 784** what kind of permissions the xAccess method is looking for. 785** With SQLITE_ACCESS_EXISTS, the xAccess method 786** simply checks whether the file exists. 787** With SQLITE_ACCESS_READWRITE, the xAccess method 788** checks whether the file is both readable and writable. 789** With SQLITE_ACCESS_READ, the xAccess method 790** checks whether the file is readable. 791*/ 792#define SQLITE_ACCESS_EXISTS 0 793#define SQLITE_ACCESS_READWRITE 1 794#define SQLITE_ACCESS_READ 2 795 796/* 797** CAPI3REF: Initialize The SQLite Library {H10130} <S20000><S30100> 798** 799** The sqlite3_initialize() routine initializes the 800** SQLite library. The sqlite3_shutdown() routine 801** deallocates any resources that were allocated by sqlite3_initialize(). 802** 803** A call to sqlite3_initialize() is an "effective" call if it is 804** the first time sqlite3_initialize() is invoked during the lifetime of 805** the process, or if it is the first time sqlite3_initialize() is invoked 806** following a call to sqlite3_shutdown(). Only an effective call 807** of sqlite3_initialize() does any initialization. All other calls 808** are harmless no-ops. 809** 810** A call to sqlite3_shutdown() is an "effective" call if it is the first 811** call to sqlite3_shutdown() since the last sqlite3_initialize(). Only 812** an effective call to sqlite3_shutdown() does any deinitialization. 813** All other calls to sqlite3_shutdown() are harmless no-ops. 814** 815** Among other things, sqlite3_initialize() shall invoke 816** sqlite3_os_init(). Similarly, sqlite3_shutdown() 817** shall invoke sqlite3_os_end(). 818** 819** The sqlite3_initialize() routine returns [SQLITE_OK] on success. 820** If for some reason, sqlite3_initialize() is unable to initialize 821** the library (perhaps it is unable to allocate a needed resource such 822** as a mutex) it returns an [error code] other than [SQLITE_OK]. 823** 824** The sqlite3_initialize() routine is called internally by many other 825** SQLite interfaces so that an application usually does not need to 826** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 827** calls sqlite3_initialize() so the SQLite library will be automatically 828** initialized when [sqlite3_open()] is called if it has not be initialized 829** already. However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 830** compile-time option, then the automatic calls to sqlite3_initialize() 831** are omitted and the application must call sqlite3_initialize() directly 832** prior to using any other SQLite interface. For maximum portability, 833** it is recommended that applications always invoke sqlite3_initialize() 834** directly prior to using any other SQLite interface. Future releases 835** of SQLite may require this. In other words, the behavior exhibited 836** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 837** default behavior in some future release of SQLite. 838** 839** The sqlite3_os_init() routine does operating-system specific 840** initialization of the SQLite library. The sqlite3_os_end() 841** routine undoes the effect of sqlite3_os_init(). Typical tasks 842** performed by these routines include allocation or deallocation 843** of static resources, initialization of global variables, 844** setting up a default [sqlite3_vfs] module, or setting up 845** a default configuration using [sqlite3_config()]. 846** 847** The application should never invoke either sqlite3_os_init() 848** or sqlite3_os_end() directly. The application should only invoke 849** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 850** interface is called automatically by sqlite3_initialize() and 851** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 852** implementations for sqlite3_os_init() and sqlite3_os_end() 853** are built into SQLite when it is compiled for unix, windows, or os/2. 854** When built for other platforms (using the [SQLITE_OS_OTHER=1] compile-time 855** option) the application must supply a suitable implementation for 856** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 857** implementation of sqlite3_os_init() or sqlite3_os_end() 858** must return [SQLITE_OK] on success and some other [error code] upon 859** failure. 860*/ 861int sqlite3_initialize(void); 862int sqlite3_shutdown(void); 863int sqlite3_os_init(void); 864int sqlite3_os_end(void); 865 866/* 867** CAPI3REF: Configuring The SQLite Library {H14100} <S20000><S30200> 868** EXPERIMENTAL 869** 870** The sqlite3_config() interface is used to make global configuration 871** changes to SQLite in order to tune SQLite to the specific needs of 872** the application. The default configuration is recommended for most 873** applications and so this routine is usually not necessary. It is 874** provided to support rare applications with unusual needs. 875** 876** The sqlite3_config() interface is not threadsafe. The application 877** must insure that no other SQLite interfaces are invoked by other 878** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 879** may only be invoked prior to library initialization using 880** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 881** Note, however, that sqlite3_config() can be called as part of the 882** implementation of an application-defined [sqlite3_os_init()]. 883** 884** The first argument to sqlite3_config() is an integer 885** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines 886** what property of SQLite is to be configured. Subsequent arguments 887** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option] 888** in the first argument. 889** 890** When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 891** If the option is unknown or SQLite is unable to set the option 892** then this routine returns a non-zero [error code]. 893** 894** Requirements: 895** [H14103] [H14106] [H14120] [H14123] [H14126] [H14129] [H14132] [H14135] 896** [H14138] [H14141] [H14144] [H14147] [H14150] [H14153] [H14156] [H14159] 897** [H14162] [H14165] [H14168] 898*/ 899SQLITE_EXPERIMENTAL int sqlite3_config(int, ...); 900 901/* 902** CAPI3REF: Configure database connections {H14200} <S20000> 903** EXPERIMENTAL 904** 905** The sqlite3_db_config() interface is used to make configuration 906** changes to a [database connection]. The interface is similar to 907** [sqlite3_config()] except that the changes apply to a single 908** [database connection] (specified in the first argument). The 909** sqlite3_db_config() interface can only be used immediately after 910** the database connection is created using [sqlite3_open()], 911** [sqlite3_open16()], or [sqlite3_open_v2()]. 912** 913** The second argument to sqlite3_db_config(D,V,...) is the 914** configuration verb - an integer code that indicates what 915** aspect of the [database connection] is being configured. 916** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE]. 917** New verbs are likely to be added in future releases of SQLite. 918** Additional arguments depend on the verb. 919** 920** Requirements: 921** [H14203] [H14206] [H14209] [H14212] [H14215] 922*/ 923SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...); 924 925/* 926** CAPI3REF: Memory Allocation Routines {H10155} <S20120> 927** EXPERIMENTAL 928** 929** An instance of this object defines the interface between SQLite 930** and low-level memory allocation routines. 931** 932** This object is used in only one place in the SQLite interface. 933** A pointer to an instance of this object is the argument to 934** [sqlite3_config()] when the configuration option is 935** [SQLITE_CONFIG_MALLOC]. By creating an instance of this object 936** and passing it to [sqlite3_config()] during configuration, an 937** application can specify an alternative memory allocation subsystem 938** for SQLite to use for all of its dynamic memory needs. 939** 940** Note that SQLite comes with a built-in memory allocator that is 941** perfectly adequate for the overwhelming majority of applications 942** and that this object is only useful to a tiny minority of applications 943** with specialized memory allocation requirements. This object is 944** also used during testing of SQLite in order to specify an alternative 945** memory allocator that simulates memory out-of-memory conditions in 946** order to verify that SQLite recovers gracefully from such 947** conditions. 948** 949** The xMalloc, xFree, and xRealloc methods must work like the 950** malloc(), free(), and realloc() functions from the standard library. 951** 952** xSize should return the allocated size of a memory allocation 953** previously obtained from xMalloc or xRealloc. The allocated size 954** is always at least as big as the requested size but may be larger. 955** 956** The xRoundup method returns what would be the allocated size of 957** a memory allocation given a particular requested size. Most memory 958** allocators round up memory allocations at least to the next multiple 959** of 8. Some allocators round up to a larger multiple or to a power of 2. 960** 961** The xInit method initializes the memory allocator. (For example, 962** it might allocate any require mutexes or initialize internal data 963** structures. The xShutdown method is invoked (indirectly) by 964** [sqlite3_shutdown()] and should deallocate any resources acquired 965** by xInit. The pAppData pointer is used as the only parameter to 966** xInit and xShutdown. 967*/ 968typedef struct sqlite3_mem_methods sqlite3_mem_methods; 969struct sqlite3_mem_methods { 970 void *(*xMalloc)(int); /* Memory allocation function */ 971 void (*xFree)(void*); /* Free a prior allocation */ 972 void *(*xRealloc)(void*,int); /* Resize an allocation */ 973 int (*xSize)(void*); /* Return the size of an allocation */ 974 int (*xRoundup)(int); /* Round up request size to allocation size */ 975 int (*xInit)(void*); /* Initialize the memory allocator */ 976 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 977 void *pAppData; /* Argument to xInit() and xShutdown() */ 978}; 979 980/* 981** CAPI3REF: Configuration Options {H10160} <S20000> 982** EXPERIMENTAL 983** 984** These constants are the available integer configuration options that 985** can be passed as the first argument to the [sqlite3_config()] interface. 986** 987** New configuration options may be added in future releases of SQLite. 988** Existing configuration options might be discontinued. Applications 989** should check the return code from [sqlite3_config()] to make sure that 990** the call worked. The [sqlite3_config()] interface will return a 991** non-zero [error code] if a discontinued or unsupported configuration option 992** is invoked. 993** 994** <dl> 995** <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 996** <dd>There are no arguments to this option. This option disables 997** all mutexing and puts SQLite into a mode where it can only be used 998** by a single thread.</dd> 999** 1000** <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1001** <dd>There are no arguments to this option. This option disables 1002** mutexing on [database connection] and [prepared statement] objects. 1003** The application is responsible for serializing access to 1004** [database connections] and [prepared statements]. But other mutexes 1005** are enabled so that SQLite will be safe to use in a multi-threaded 1006** environment as long as no two threads attempt to use the same 1007** [database connection] at the same time. See the [threading mode] 1008** documentation for additional information.</dd> 1009** 1010** <dt>SQLITE_CONFIG_SERIALIZED</dt> 1011** <dd>There are no arguments to this option. This option enables 1012** all mutexes including the recursive 1013** mutexes on [database connection] and [prepared statement] objects. 1014** In this mode (which is the default when SQLite is compiled with 1015** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1016** to [database connections] and [prepared statements] so that the 1017** application is free to use the same [database connection] or the 1018** same [prepared statement] in different threads at the same time. 1019** See the [threading mode] documentation for additional information.</dd> 1020** 1021** <dt>SQLITE_CONFIG_MALLOC</dt> 1022** <dd>This option takes a single argument which is a pointer to an 1023** instance of the [sqlite3_mem_methods] structure. The argument specifies 1024** alternative low-level memory allocation routines to be used in place of 1025** the memory allocation routines built into SQLite.</dd> 1026** 1027** <dt>SQLITE_CONFIG_GETMALLOC</dt> 1028** <dd>This option takes a single argument which is a pointer to an 1029** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1030** structure is filled with the currently defined memory allocation routines. 1031** This option can be used to overload the default memory allocation 1032** routines with a wrapper that simulations memory allocation failure or 1033** tracks memory usage, for example.</dd> 1034** 1035** <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1036** <dd>This option takes single argument of type int, interpreted as a 1037** boolean, which enables or disables the collection of memory allocation 1038** statistics. When disabled, the following SQLite interfaces become 1039** non-operational: 1040** <ul> 1041** <li> [sqlite3_memory_used()] 1042** <li> [sqlite3_memory_highwater()] 1043** <li> [sqlite3_soft_heap_limit()] 1044** <li> [sqlite3_status()] 1045** </ul> 1046** </dd> 1047** 1048** <dt>SQLITE_CONFIG_SCRATCH</dt> 1049** <dd>This option specifies a static memory buffer that SQLite can use for 1050** scratch memory. There are three arguments: A pointer an 8-byte 1051** aligned memory buffer from which the scrach allocations will be 1052** drawn, the size of each scratch allocation (sz), 1053** and the maximum number of scratch allocations (N). The sz 1054** argument must be a multiple of 16. The sz parameter should be a few bytes 1055** larger than the actual scratch space required due to internal overhead. 1056** The first argument should pointer to an 8-byte aligned buffer 1057** of at least sz*N bytes of memory. 1058** SQLite will use no more than one scratch buffer at once per thread, so 1059** N should be set to the expected maximum number of threads. The sz 1060** parameter should be 6 times the size of the largest database page size. 1061** Scratch buffers are used as part of the btree balance operation. If 1062** The btree balancer needs additional memory beyond what is provided by 1063** scratch buffers or if no scratch buffer space is specified, then SQLite 1064** goes to [sqlite3_malloc()] to obtain the memory it needs.</dd> 1065** 1066** <dt>SQLITE_CONFIG_PAGECACHE</dt> 1067** <dd>This option specifies a static memory buffer that SQLite can use for 1068** the database page cache with the default page cache implemenation. 1069** This configuration should not be used if an application-define page 1070** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option. 1071** There are three arguments to this option: A pointer to 8-byte aligned 1072** memory, the size of each page buffer (sz), and the number of pages (N). 1073** The sz argument should be the size of the largest database page 1074** (a power of two between 512 and 32768) plus a little extra for each 1075** page header. The page header size is 20 to 40 bytes depending on 1076** the host architecture. It is harmless, apart from the wasted memory, 1077** to make sz a little too large. The first 1078** argument should point to an allocation of at least sz*N bytes of memory. 1079** SQLite will use the memory provided by the first argument to satisfy its 1080** memory needs for the first N pages that it adds to cache. If additional 1081** page cache memory is needed beyond what is provided by this option, then 1082** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1083** The implementation might use one or more of the N buffers to hold 1084** memory accounting information. The pointer in the first argument must 1085** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1086** will be undefined.</dd> 1087** 1088** <dt>SQLITE_CONFIG_HEAP</dt> 1089** <dd>This option specifies a static memory buffer that SQLite will use 1090** for all of its dynamic memory allocation needs beyond those provided 1091** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1092** There are three arguments: An 8-byte aligned pointer to the memory, 1093** the number of bytes in the memory buffer, and the minimum allocation size. 1094** If the first pointer (the memory pointer) is NULL, then SQLite reverts 1095** to using its default memory allocator (the system malloc() implementation), 1096** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. If the 1097** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1098** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1099** allocator is engaged to handle all of SQLites memory allocation needs. 1100** The first pointer (the memory pointer) must be aligned to an 8-byte 1101** boundary or subsequent behavior of SQLite will be undefined.</dd> 1102** 1103** <dt>SQLITE_CONFIG_MUTEX</dt> 1104** <dd>This option takes a single argument which is a pointer to an 1105** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1106** alternative low-level mutex routines to be used in place 1107** the mutex routines built into SQLite.</dd> 1108** 1109** <dt>SQLITE_CONFIG_GETMUTEX</dt> 1110** <dd>This option takes a single argument which is a pointer to an 1111** instance of the [sqlite3_mutex_methods] structure. The 1112** [sqlite3_mutex_methods] 1113** structure is filled with the currently defined mutex routines. 1114** This option can be used to overload the default mutex allocation 1115** routines with a wrapper used to track mutex usage for performance 1116** profiling or testing, for example.</dd> 1117** 1118** <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1119** <dd>This option takes two arguments that determine the default 1120** memory allcation lookaside optimization. The first argument is the 1121** size of each lookaside buffer slot and the second is the number of 1122** slots allocated to each database connection.</dd> 1123** 1124** <dt>SQLITE_CONFIG_PCACHE</dt> 1125** <dd>This option takes a single argument which is a pointer to 1126** an [sqlite3_pcache_methods] object. This object specifies the interface 1127** to a custom page cache implementation. SQLite makes a copy of the 1128** object and uses it for page cache memory allocations.</dd> 1129** 1130** <dt>SQLITE_CONFIG_GETPCACHE</dt> 1131** <dd>This option takes a single argument which is a pointer to an 1132** [sqlite3_pcache_methods] object. SQLite copies of the current 1133** page cache implementation into that object.</dd> 1134** 1135** </dl> 1136*/ 1137#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1138#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1139#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1140#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1141#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1142#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1143#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1144#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1145#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1146#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1147#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1148/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1149#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1150#define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */ 1151#define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */ 1152 1153/* 1154** CAPI3REF: Configuration Options {H10170} <S20000> 1155** EXPERIMENTAL 1156** 1157** These constants are the available integer configuration options that 1158** can be passed as the second argument to the [sqlite3_db_config()] interface. 1159** 1160** New configuration options may be added in future releases of SQLite. 1161** Existing configuration options might be discontinued. Applications 1162** should check the return code from [sqlite3_db_config()] to make sure that 1163** the call worked. The [sqlite3_db_config()] interface will return a 1164** non-zero [error code] if a discontinued or unsupported configuration option 1165** is invoked. 1166** 1167** <dl> 1168** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1169** <dd>This option takes three additional arguments that determine the 1170** [lookaside memory allocator] configuration for the [database connection]. 1171** The first argument (the third parameter to [sqlite3_db_config()] is a 1172** pointer to an 8-byte aligned memory buffer to use for lookaside memory. 1173** The first argument may be NULL in which case SQLite will allocate the 1174** lookaside buffer itself using [sqlite3_malloc()]. The second argument is the 1175** size of each lookaside buffer slot and the third argument is the number of 1176** slots. The size of the buffer in the first argument must be greater than 1177** or equal to the product of the second and third arguments.</dd> 1178** 1179** </dl> 1180*/ 1181#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1182 1183 1184/* 1185** CAPI3REF: Enable Or Disable Extended Result Codes {H12200} <S10700> 1186** 1187** The sqlite3_extended_result_codes() routine enables or disables the 1188** [extended result codes] feature of SQLite. The extended result 1189** codes are disabled by default for historical compatibility considerations. 1190** 1191** Requirements: 1192** [H12201] [H12202] 1193*/ 1194int sqlite3_extended_result_codes(sqlite3*, int onoff); 1195 1196/* 1197** CAPI3REF: Last Insert Rowid {H12220} <S10700> 1198** 1199** Each entry in an SQLite table has a unique 64-bit signed 1200** integer key called the [ROWID | "rowid"]. The rowid is always available 1201** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1202** names are not also used by explicitly declared columns. If 1203** the table has a column of type [INTEGER PRIMARY KEY] then that column 1204** is another alias for the rowid. 1205** 1206** This routine returns the [rowid] of the most recent 1207** successful [INSERT] into the database from the [database connection] 1208** in the first argument. If no successful [INSERT]s 1209** have ever occurred on that database connection, zero is returned. 1210** 1211** If an [INSERT] occurs within a trigger, then the [rowid] of the inserted 1212** row is returned by this routine as long as the trigger is running. 1213** But once the trigger terminates, the value returned by this routine 1214** reverts to the last value inserted before the trigger fired. 1215** 1216** An [INSERT] that fails due to a constraint violation is not a 1217** successful [INSERT] and does not change the value returned by this 1218** routine. Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1219** and INSERT OR ABORT make no changes to the return value of this 1220** routine when their insertion fails. When INSERT OR REPLACE 1221** encounters a constraint violation, it does not fail. The 1222** INSERT continues to completion after deleting rows that caused 1223** the constraint problem so INSERT OR REPLACE will always change 1224** the return value of this interface. 1225** 1226** For the purposes of this routine, an [INSERT] is considered to 1227** be successful even if it is subsequently rolled back. 1228** 1229** Requirements: 1230** [H12221] [H12223] 1231** 1232** If a separate thread performs a new [INSERT] on the same 1233** database connection while the [sqlite3_last_insert_rowid()] 1234** function is running and thus changes the last insert [rowid], 1235** then the value returned by [sqlite3_last_insert_rowid()] is 1236** unpredictable and might not equal either the old or the new 1237** last insert [rowid]. 1238*/ 1239sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1240 1241/* 1242** CAPI3REF: Count The Number Of Rows Modified {H12240} <S10600> 1243** 1244** This function returns the number of database rows that were changed 1245** or inserted or deleted by the most recently completed SQL statement 1246** on the [database connection] specified by the first parameter. 1247** Only changes that are directly specified by the [INSERT], [UPDATE], 1248** or [DELETE] statement are counted. Auxiliary changes caused by 1249** triggers are not counted. Use the [sqlite3_total_changes()] function 1250** to find the total number of changes including changes caused by triggers. 1251** 1252** Changes to a view that are simulated by an [INSTEAD OF trigger] 1253** are not counted. Only real table changes are counted. 1254** 1255** A "row change" is a change to a single row of a single table 1256** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1257** are changed as side effects of [REPLACE] constraint resolution, 1258** rollback, ABORT processing, [DROP TABLE], or by any other 1259** mechanisms do not count as direct row changes. 1260** 1261** A "trigger context" is a scope of execution that begins and 1262** ends with the script of a [CREATE TRIGGER | trigger]. 1263** Most SQL statements are 1264** evaluated outside of any trigger. This is the "top level" 1265** trigger context. If a trigger fires from the top level, a 1266** new trigger context is entered for the duration of that one 1267** trigger. Subtriggers create subcontexts for their duration. 1268** 1269** Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1270** not create a new trigger context. 1271** 1272** This function returns the number of direct row changes in the 1273** most recent INSERT, UPDATE, or DELETE statement within the same 1274** trigger context. 1275** 1276** Thus, when called from the top level, this function returns the 1277** number of changes in the most recent INSERT, UPDATE, or DELETE 1278** that also occurred at the top level. Within the body of a trigger, 1279** the sqlite3_changes() interface can be called to find the number of 1280** changes in the most recently completed INSERT, UPDATE, or DELETE 1281** statement within the body of the same trigger. 1282** However, the number returned does not include changes 1283** caused by subtriggers since those have their own context. 1284** 1285** See also the [sqlite3_total_changes()] interface and the 1286** [count_changes pragma]. 1287** 1288** Requirements: 1289** [H12241] [H12243] 1290** 1291** If a separate thread makes changes on the same database connection 1292** while [sqlite3_changes()] is running then the value returned 1293** is unpredictable and not meaningful. 1294*/ 1295int sqlite3_changes(sqlite3*); 1296 1297/* 1298** CAPI3REF: Total Number Of Rows Modified {H12260} <S10600> 1299** 1300** This function returns the number of row changes caused by [INSERT], 1301** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1302** The count includes all changes from all 1303** [CREATE TRIGGER | trigger] contexts. However, 1304** the count does not include changes used to implement [REPLACE] constraints, 1305** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1306** count does not include rows of views that fire an [INSTEAD OF trigger], 1307** though if the INSTEAD OF trigger makes changes of its own, those changes 1308** are counted. 1309** The changes are counted as soon as the statement that makes them is 1310** completed (when the statement handle is passed to [sqlite3_reset()] or 1311** [sqlite3_finalize()]). 1312** 1313** See also the [sqlite3_changes()] interface and the 1314** [count_changes pragma]. 1315** 1316** Requirements: 1317** [H12261] [H12263] 1318** 1319** If a separate thread makes changes on the same database connection 1320** while [sqlite3_total_changes()] is running then the value 1321** returned is unpredictable and not meaningful. 1322*/ 1323int sqlite3_total_changes(sqlite3*); 1324 1325/* 1326** CAPI3REF: Interrupt A Long-Running Query {H12270} <S30500> 1327** 1328** This function causes any pending database operation to abort and 1329** return at its earliest opportunity. This routine is typically 1330** called in response to a user action such as pressing "Cancel" 1331** or Ctrl-C where the user wants a long query operation to halt 1332** immediately. 1333** 1334** It is safe to call this routine from a thread different from the 1335** thread that is currently running the database operation. But it 1336** is not safe to call this routine with a [database connection] that 1337** is closed or might close before sqlite3_interrupt() returns. 1338** 1339** If an SQL operation is very nearly finished at the time when 1340** sqlite3_interrupt() is called, then it might not have an opportunity 1341** to be interrupted and might continue to completion. 1342** 1343** An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1344** If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1345** that is inside an explicit transaction, then the entire transaction 1346** will be rolled back automatically. 1347** 1348** The sqlite3_interrupt(D) call is in effect until all currently running 1349** SQL statements on [database connection] D complete. Any new SQL statements 1350** that are started after the sqlite3_interrupt() call and before the 1351** running statements reaches zero are interrupted as if they had been 1352** running prior to the sqlite3_interrupt() call. New SQL statements 1353** that are started after the running statement count reaches zero are 1354** not effected by the sqlite3_interrupt(). 1355** A call to sqlite3_interrupt(D) that occurs when there are no running 1356** SQL statements is a no-op and has no effect on SQL statements 1357** that are started after the sqlite3_interrupt() call returns. 1358** 1359** Requirements: 1360** [H12271] [H12272] 1361** 1362** If the database connection closes while [sqlite3_interrupt()] 1363** is running then bad things will likely happen. 1364*/ 1365void sqlite3_interrupt(sqlite3*); 1366 1367/* 1368** CAPI3REF: Determine If An SQL Statement Is Complete {H10510} <S70200> 1369** 1370** These routines are useful during command-line input to determine if the 1371** currently entered text seems to form a complete SQL statement or 1372** if additional input is needed before sending the text into 1373** SQLite for parsing. These routines return 1 if the input string 1374** appears to be a complete SQL statement. A statement is judged to be 1375** complete if it ends with a semicolon token and is not a prefix of a 1376** well-formed CREATE TRIGGER statement. Semicolons that are embedded within 1377** string literals or quoted identifier names or comments are not 1378** independent tokens (they are part of the token in which they are 1379** embedded) and thus do not count as a statement terminator. Whitespace 1380** and comments that follow the final semicolon are ignored. 1381** 1382** These routines return 0 if the statement is incomplete. If a 1383** memory allocation fails, then SQLITE_NOMEM is returned. 1384** 1385** These routines do not parse the SQL statements thus 1386** will not detect syntactically incorrect SQL. 1387** 1388** If SQLite has not been initialized using [sqlite3_initialize()] prior 1389** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1390** automatically by sqlite3_complete16(). If that initialization fails, 1391** then the return value from sqlite3_complete16() will be non-zero 1392** regardless of whether or not the input SQL is complete. 1393** 1394** Requirements: [H10511] [H10512] 1395** 1396** The input to [sqlite3_complete()] must be a zero-terminated 1397** UTF-8 string. 1398** 1399** The input to [sqlite3_complete16()] must be a zero-terminated 1400** UTF-16 string in native byte order. 1401*/ 1402int sqlite3_complete(const char *sql); 1403int sqlite3_complete16(const void *sql); 1404 1405/* 1406** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors {H12310} <S40400> 1407** 1408** This routine sets a callback function that might be invoked whenever 1409** an attempt is made to open a database table that another thread 1410** or process has locked. 1411** 1412** If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1413** is returned immediately upon encountering the lock. If the busy callback 1414** is not NULL, then the callback will be invoked with two arguments. 1415** 1416** The first argument to the handler is a copy of the void* pointer which 1417** is the third argument to sqlite3_busy_handler(). The second argument to 1418** the handler callback is the number of times that the busy handler has 1419** been invoked for this locking event. If the 1420** busy callback returns 0, then no additional attempts are made to 1421** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1422** If the callback returns non-zero, then another attempt 1423** is made to open the database for reading and the cycle repeats. 1424** 1425** The presence of a busy handler does not guarantee that it will be invoked 1426** when there is lock contention. If SQLite determines that invoking the busy 1427** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1428** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1429** Consider a scenario where one process is holding a read lock that 1430** it is trying to promote to a reserved lock and 1431** a second process is holding a reserved lock that it is trying 1432** to promote to an exclusive lock. The first process cannot proceed 1433** because it is blocked by the second and the second process cannot 1434** proceed because it is blocked by the first. If both processes 1435** invoke the busy handlers, neither will make any progress. Therefore, 1436** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1437** will induce the first process to release its read lock and allow 1438** the second process to proceed. 1439** 1440** The default busy callback is NULL. 1441** 1442** The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1443** when SQLite is in the middle of a large transaction where all the 1444** changes will not fit into the in-memory cache. SQLite will 1445** already hold a RESERVED lock on the database file, but it needs 1446** to promote this lock to EXCLUSIVE so that it can spill cache 1447** pages into the database file without harm to concurrent 1448** readers. If it is unable to promote the lock, then the in-memory 1449** cache will be left in an inconsistent state and so the error 1450** code is promoted from the relatively benign [SQLITE_BUSY] to 1451** the more severe [SQLITE_IOERR_BLOCKED]. This error code promotion 1452** forces an automatic rollback of the changes. See the 1453** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1454** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1455** this is important. 1456** 1457** There can only be a single busy handler defined for each 1458** [database connection]. Setting a new busy handler clears any 1459** previously set handler. Note that calling [sqlite3_busy_timeout()] 1460** will also set or clear the busy handler. 1461** 1462** The busy callback should not take any actions which modify the 1463** database connection that invoked the busy handler. Any such actions 1464** result in undefined behavior. 1465** 1466** Requirements: 1467** [H12311] [H12312] [H12314] [H12316] [H12318] 1468** 1469** A busy handler must not close the database connection 1470** or [prepared statement] that invoked the busy handler. 1471*/ 1472int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1473 1474/* 1475** CAPI3REF: Set A Busy Timeout {H12340} <S40410> 1476** 1477** This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1478** for a specified amount of time when a table is locked. The handler 1479** will sleep multiple times until at least "ms" milliseconds of sleeping 1480** have accumulated. {H12343} After "ms" milliseconds of sleeping, 1481** the handler returns 0 which causes [sqlite3_step()] to return 1482** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1483** 1484** Calling this routine with an argument less than or equal to zero 1485** turns off all busy handlers. 1486** 1487** There can only be a single busy handler for a particular 1488** [database connection] any any given moment. If another busy handler 1489** was defined (using [sqlite3_busy_handler()]) prior to calling 1490** this routine, that other busy handler is cleared. 1491** 1492** Requirements: 1493** [H12341] [H12343] [H12344] 1494*/ 1495int sqlite3_busy_timeout(sqlite3*, int ms); 1496 1497/* 1498** CAPI3REF: Convenience Routines For Running Queries {H12370} <S10000> 1499** 1500** Definition: A <b>result table</b> is memory data structure created by the 1501** [sqlite3_get_table()] interface. A result table records the 1502** complete query results from one or more queries. 1503** 1504** The table conceptually has a number of rows and columns. But 1505** these numbers are not part of the result table itself. These 1506** numbers are obtained separately. Let N be the number of rows 1507** and M be the number of columns. 1508** 1509** A result table is an array of pointers to zero-terminated UTF-8 strings. 1510** There are (N+1)*M elements in the array. The first M pointers point 1511** to zero-terminated strings that contain the names of the columns. 1512** The remaining entries all point to query results. NULL values result 1513** in NULL pointers. All other values are in their UTF-8 zero-terminated 1514** string representation as returned by [sqlite3_column_text()]. 1515** 1516** A result table might consist of one or more memory allocations. 1517** It is not safe to pass a result table directly to [sqlite3_free()]. 1518** A result table should be deallocated using [sqlite3_free_table()]. 1519** 1520** As an example of the result table format, suppose a query result 1521** is as follows: 1522** 1523** <blockquote><pre> 1524** Name | Age 1525** ----------------------- 1526** Alice | 43 1527** Bob | 28 1528** Cindy | 21 1529** </pre></blockquote> 1530** 1531** There are two column (M==2) and three rows (N==3). Thus the 1532** result table has 8 entries. Suppose the result table is stored 1533** in an array names azResult. Then azResult holds this content: 1534** 1535** <blockquote><pre> 1536** azResult[0] = "Name"; 1537** azResult[1] = "Age"; 1538** azResult[2] = "Alice"; 1539** azResult[3] = "43"; 1540** azResult[4] = "Bob"; 1541** azResult[5] = "28"; 1542** azResult[6] = "Cindy"; 1543** azResult[7] = "21"; 1544** </pre></blockquote> 1545** 1546** The sqlite3_get_table() function evaluates one or more 1547** semicolon-separated SQL statements in the zero-terminated UTF-8 1548** string of its 2nd parameter. It returns a result table to the 1549** pointer given in its 3rd parameter. 1550** 1551** After the calling function has finished using the result, it should 1552** pass the pointer to the result table to sqlite3_free_table() in order to 1553** release the memory that was malloced. Because of the way the 1554** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1555** function must not try to call [sqlite3_free()] directly. Only 1556** [sqlite3_free_table()] is able to release the memory properly and safely. 1557** 1558** The sqlite3_get_table() interface is implemented as a wrapper around 1559** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 1560** to any internal data structures of SQLite. It uses only the public 1561** interface defined here. As a consequence, errors that occur in the 1562** wrapper layer outside of the internal [sqlite3_exec()] call are not 1563** reflected in subsequent calls to [sqlite3_errcode()] or [sqlite3_errmsg()]. 1564** 1565** Requirements: 1566** [H12371] [H12373] [H12374] [H12376] [H12379] [H12382] 1567*/ 1568int sqlite3_get_table( 1569 sqlite3 *db, /* An open database */ 1570 const char *zSql, /* SQL to be evaluated */ 1571 char ***pazResult, /* Results of the query */ 1572 int *pnRow, /* Number of result rows written here */ 1573 int *pnColumn, /* Number of result columns written here */ 1574 char **pzErrmsg /* Error msg written here */ 1575); 1576void sqlite3_free_table(char **result); 1577 1578/* 1579** CAPI3REF: Formatted String Printing Functions {H17400} <S70000><S20000> 1580** 1581** These routines are workalikes of the "printf()" family of functions 1582** from the standard C library. 1583** 1584** The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 1585** results into memory obtained from [sqlite3_malloc()]. 1586** The strings returned by these two routines should be 1587** released by [sqlite3_free()]. Both routines return a 1588** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 1589** memory to hold the resulting string. 1590** 1591** In sqlite3_snprintf() routine is similar to "snprintf()" from 1592** the standard C library. The result is written into the 1593** buffer supplied as the second parameter whose size is given by 1594** the first parameter. Note that the order of the 1595** first two parameters is reversed from snprintf(). This is an 1596** historical accident that cannot be fixed without breaking 1597** backwards compatibility. Note also that sqlite3_snprintf() 1598** returns a pointer to its buffer instead of the number of 1599** characters actually written into the buffer. We admit that 1600** the number of characters written would be a more useful return 1601** value but we cannot change the implementation of sqlite3_snprintf() 1602** now without breaking compatibility. 1603** 1604** As long as the buffer size is greater than zero, sqlite3_snprintf() 1605** guarantees that the buffer is always zero-terminated. The first 1606** parameter "n" is the total size of the buffer, including space for 1607** the zero terminator. So the longest string that can be completely 1608** written will be n-1 characters. 1609** 1610** These routines all implement some additional formatting 1611** options that are useful for constructing SQL statements. 1612** All of the usual printf() formatting options apply. In addition, there 1613** is are "%q", "%Q", and "%z" options. 1614** 1615** The %q option works like %s in that it substitutes a null-terminated 1616** string from the argument list. But %q also doubles every '\'' character. 1617** %q is designed for use inside a string literal. By doubling each '\'' 1618** character it escapes that character and allows it to be inserted into 1619** the string. 1620** 1621** For example, assume the string variable zText contains text as follows: 1622** 1623** <blockquote><pre> 1624** char *zText = "It's a happy day!"; 1625** </pre></blockquote> 1626** 1627** One can use this text in an SQL statement as follows: 1628** 1629** <blockquote><pre> 1630** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 1631** sqlite3_exec(db, zSQL, 0, 0, 0); 1632** sqlite3_free(zSQL); 1633** </pre></blockquote> 1634** 1635** Because the %q format string is used, the '\'' character in zText 1636** is escaped and the SQL generated is as follows: 1637** 1638** <blockquote><pre> 1639** INSERT INTO table1 VALUES('It''s a happy day!') 1640** </pre></blockquote> 1641** 1642** This is correct. Had we used %s instead of %q, the generated SQL 1643** would have looked like this: 1644** 1645** <blockquote><pre> 1646** INSERT INTO table1 VALUES('It's a happy day!'); 1647** </pre></blockquote> 1648** 1649** This second example is an SQL syntax error. As a general rule you should 1650** always use %q instead of %s when inserting text into a string literal. 1651** 1652** The %Q option works like %q except it also adds single quotes around 1653** the outside of the total string. Additionally, if the parameter in the 1654** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 1655** single quotes) in place of the %Q option. So, for example, one could say: 1656** 1657** <blockquote><pre> 1658** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 1659** sqlite3_exec(db, zSQL, 0, 0, 0); 1660** sqlite3_free(zSQL); 1661** </pre></blockquote> 1662** 1663** The code above will render a correct SQL statement in the zSQL 1664** variable even if the zText variable is a NULL pointer. 1665** 1666** The "%z" formatting option works exactly like "%s" with the 1667** addition that after the string has been read and copied into 1668** the result, [sqlite3_free()] is called on the input string. {END} 1669** 1670** Requirements: 1671** [H17403] [H17406] [H17407] 1672*/ 1673char *sqlite3_mprintf(const char*,...); 1674char *sqlite3_vmprintf(const char*, va_list); 1675char *sqlite3_snprintf(int,char*,const char*, ...); 1676 1677/* 1678** CAPI3REF: Memory Allocation Subsystem {H17300} <S20000> 1679** 1680** The SQLite core uses these three routines for all of its own 1681** internal memory allocation needs. "Core" in the previous sentence 1682** does not include operating-system specific VFS implementation. The 1683** Windows VFS uses native malloc() and free() for some operations. 1684** 1685** The sqlite3_malloc() routine returns a pointer to a block 1686** of memory at least N bytes in length, where N is the parameter. 1687** If sqlite3_malloc() is unable to obtain sufficient free 1688** memory, it returns a NULL pointer. If the parameter N to 1689** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 1690** a NULL pointer. 1691** 1692** Calling sqlite3_free() with a pointer previously returned 1693** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 1694** that it might be reused. The sqlite3_free() routine is 1695** a no-op if is called with a NULL pointer. Passing a NULL pointer 1696** to sqlite3_free() is harmless. After being freed, memory 1697** should neither be read nor written. Even reading previously freed 1698** memory might result in a segmentation fault or other severe error. 1699** Memory corruption, a segmentation fault, or other severe error 1700** might result if sqlite3_free() is called with a non-NULL pointer that 1701** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 1702** 1703** The sqlite3_realloc() interface attempts to resize a 1704** prior memory allocation to be at least N bytes, where N is the 1705** second parameter. The memory allocation to be resized is the first 1706** parameter. If the first parameter to sqlite3_realloc() 1707** is a NULL pointer then its behavior is identical to calling 1708** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 1709** If the second parameter to sqlite3_realloc() is zero or 1710** negative then the behavior is exactly the same as calling 1711** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 1712** sqlite3_realloc() returns a pointer to a memory allocation 1713** of at least N bytes in size or NULL if sufficient memory is unavailable. 1714** If M is the size of the prior allocation, then min(N,M) bytes 1715** of the prior allocation are copied into the beginning of buffer returned 1716** by sqlite3_realloc() and the prior allocation is freed. 1717** If sqlite3_realloc() returns NULL, then the prior allocation 1718** is not freed. 1719** 1720** The memory returned by sqlite3_malloc() and sqlite3_realloc() 1721** is always aligned to at least an 8 byte boundary. {END} 1722** 1723** The default implementation of the memory allocation subsystem uses 1724** the malloc(), realloc() and free() provided by the standard C library. 1725** {H17382} However, if SQLite is compiled with the 1726** SQLITE_MEMORY_SIZE=<i>NNN</i> C preprocessor macro (where <i>NNN</i> 1727** is an integer), then SQLite create a static array of at least 1728** <i>NNN</i> bytes in size and uses that array for all of its dynamic 1729** memory allocation needs. {END} Additional memory allocator options 1730** may be added in future releases. 1731** 1732** In SQLite version 3.5.0 and 3.5.1, it was possible to define 1733** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 1734** implementation of these routines to be omitted. That capability 1735** is no longer provided. Only built-in memory allocators can be used. 1736** 1737** The Windows OS interface layer calls 1738** the system malloc() and free() directly when converting 1739** filenames between the UTF-8 encoding used by SQLite 1740** and whatever filename encoding is used by the particular Windows 1741** installation. Memory allocation errors are detected, but 1742** they are reported back as [SQLITE_CANTOPEN] or 1743** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 1744** 1745** Requirements: 1746** [H17303] [H17304] [H17305] [H17306] [H17310] [H17312] [H17315] [H17318] 1747** [H17321] [H17322] [H17323] 1748** 1749** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 1750** must be either NULL or else pointers obtained from a prior 1751** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 1752** not yet been released. 1753** 1754** The application must not read or write any part of 1755** a block of memory after it has been released using 1756** [sqlite3_free()] or [sqlite3_realloc()]. 1757*/ 1758void *sqlite3_malloc(int); 1759void *sqlite3_realloc(void*, int); 1760void sqlite3_free(void*); 1761 1762/* 1763** CAPI3REF: Memory Allocator Statistics {H17370} <S30210> 1764** 1765** SQLite provides these two interfaces for reporting on the status 1766** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 1767** routines, which form the built-in memory allocation subsystem. 1768** 1769** Requirements: 1770** [H17371] [H17373] [H17374] [H17375] 1771*/ 1772sqlite3_int64 sqlite3_memory_used(void); 1773sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 1774 1775/* 1776** CAPI3REF: Pseudo-Random Number Generator {H17390} <S20000> 1777** 1778** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 1779** select random [ROWID | ROWIDs] when inserting new records into a table that 1780** already uses the largest possible [ROWID]. The PRNG is also used for 1781** the build-in random() and randomblob() SQL functions. This interface allows 1782** applications to access the same PRNG for other purposes. 1783** 1784** A call to this routine stores N bytes of randomness into buffer P. 1785** 1786** The first time this routine is invoked (either internally or by 1787** the application) the PRNG is seeded using randomness obtained 1788** from the xRandomness method of the default [sqlite3_vfs] object. 1789** On all subsequent invocations, the pseudo-randomness is generated 1790** internally and without recourse to the [sqlite3_vfs] xRandomness 1791** method. 1792** 1793** Requirements: 1794** [H17392] 1795*/ 1796void sqlite3_randomness(int N, void *P); 1797 1798/* 1799** CAPI3REF: Compile-Time Authorization Callbacks {H12500} <S70100> 1800** 1801** This routine registers a authorizer callback with a particular 1802** [database connection], supplied in the first argument. 1803** The authorizer callback is invoked as SQL statements are being compiled 1804** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 1805** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. At various 1806** points during the compilation process, as logic is being created 1807** to perform various actions, the authorizer callback is invoked to 1808** see if those actions are allowed. The authorizer callback should 1809** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 1810** specific action but allow the SQL statement to continue to be 1811** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 1812** rejected with an error. If the authorizer callback returns 1813** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 1814** then the [sqlite3_prepare_v2()] or equivalent call that triggered 1815** the authorizer will fail with an error message. 1816** 1817** When the callback returns [SQLITE_OK], that means the operation 1818** requested is ok. When the callback returns [SQLITE_DENY], the 1819** [sqlite3_prepare_v2()] or equivalent call that triggered the 1820** authorizer will fail with an error message explaining that 1821** access is denied. 1822** 1823** The first parameter to the authorizer callback is a copy of the third 1824** parameter to the sqlite3_set_authorizer() interface. The second parameter 1825** to the callback is an integer [SQLITE_COPY | action code] that specifies 1826** the particular action to be authorized. The third through sixth parameters 1827** to the callback are zero-terminated strings that contain additional 1828** details about the action to be authorized. 1829** 1830** If the action code is [SQLITE_READ] 1831** and the callback returns [SQLITE_IGNORE] then the 1832** [prepared statement] statement is constructed to substitute 1833** a NULL value in place of the table column that would have 1834** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 1835** return can be used to deny an untrusted user access to individual 1836** columns of a table. 1837** If the action code is [SQLITE_DELETE] and the callback returns 1838** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 1839** [truncate optimization] is disabled and all rows are deleted individually. 1840** 1841** An authorizer is used when [sqlite3_prepare | preparing] 1842** SQL statements from an untrusted source, to ensure that the SQL statements 1843** do not try to access data they are not allowed to see, or that they do not 1844** try to execute malicious statements that damage the database. For 1845** example, an application may allow a user to enter arbitrary 1846** SQL queries for evaluation by a database. But the application does 1847** not want the user to be able to make arbitrary changes to the 1848** database. An authorizer could then be put in place while the 1849** user-entered SQL is being [sqlite3_prepare | prepared] that 1850** disallows everything except [SELECT] statements. 1851** 1852** Applications that need to process SQL from untrusted sources 1853** might also consider lowering resource limits using [sqlite3_limit()] 1854** and limiting database size using the [max_page_count] [PRAGMA] 1855** in addition to using an authorizer. 1856** 1857** Only a single authorizer can be in place on a database connection 1858** at a time. Each call to sqlite3_set_authorizer overrides the 1859** previous call. Disable the authorizer by installing a NULL callback. 1860** The authorizer is disabled by default. 1861** 1862** The authorizer callback must not do anything that will modify 1863** the database connection that invoked the authorizer callback. 1864** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 1865** database connections for the meaning of "modify" in this paragraph. 1866** 1867** When [sqlite3_prepare_v2()] is used to prepare a statement, the 1868** statement might be reprepared during [sqlite3_step()] due to a 1869** schema change. Hence, the application should ensure that the 1870** correct authorizer callback remains in place during the [sqlite3_step()]. 1871** 1872** Note that the authorizer callback is invoked only during 1873** [sqlite3_prepare()] or its variants. Authorization is not 1874** performed during statement evaluation in [sqlite3_step()], unless 1875** as stated in the previous paragraph, sqlite3_step() invokes 1876** sqlite3_prepare_v2() to reprepare a statement after a schema change. 1877** 1878** Requirements: 1879** [H12501] [H12502] [H12503] [H12504] [H12505] [H12506] [H12507] [H12510] 1880** [H12511] [H12512] [H12520] [H12521] [H12522] 1881*/ 1882int sqlite3_set_authorizer( 1883 sqlite3*, 1884 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 1885 void *pUserData 1886); 1887 1888/* 1889** CAPI3REF: Authorizer Return Codes {H12590} <H12500> 1890** 1891** The [sqlite3_set_authorizer | authorizer callback function] must 1892** return either [SQLITE_OK] or one of these two constants in order 1893** to signal SQLite whether or not the action is permitted. See the 1894** [sqlite3_set_authorizer | authorizer documentation] for additional 1895** information. 1896*/ 1897#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 1898#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 1899 1900/* 1901** CAPI3REF: Authorizer Action Codes {H12550} <H12500> 1902** 1903** The [sqlite3_set_authorizer()] interface registers a callback function 1904** that is invoked to authorize certain SQL statement actions. The 1905** second parameter to the callback is an integer code that specifies 1906** what action is being authorized. These are the integer action codes that 1907** the authorizer callback may be passed. 1908** 1909** These action code values signify what kind of operation is to be 1910** authorized. The 3rd and 4th parameters to the authorization 1911** callback function will be parameters or NULL depending on which of these 1912** codes is used as the second parameter. The 5th parameter to the 1913** authorizer callback is the name of the database ("main", "temp", 1914** etc.) if applicable. The 6th parameter to the authorizer callback 1915** is the name of the inner-most trigger or view that is responsible for 1916** the access attempt or NULL if this access attempt is directly from 1917** top-level SQL code. 1918** 1919** Requirements: 1920** [H12551] [H12552] [H12553] [H12554] 1921*/ 1922/******************************************* 3rd ************ 4th ***********/ 1923#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 1924#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 1925#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 1926#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 1927#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 1928#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 1929#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 1930#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 1931#define SQLITE_DELETE 9 /* Table Name NULL */ 1932#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 1933#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 1934#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 1935#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 1936#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 1937#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 1938#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 1939#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 1940#define SQLITE_INSERT 18 /* Table Name NULL */ 1941#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 1942#define SQLITE_READ 20 /* Table Name Column Name */ 1943#define SQLITE_SELECT 21 /* NULL NULL */ 1944#define SQLITE_TRANSACTION 22 /* Operation NULL */ 1945#define SQLITE_UPDATE 23 /* Table Name Column Name */ 1946#define SQLITE_ATTACH 24 /* Filename NULL */ 1947#define SQLITE_DETACH 25 /* Database Name NULL */ 1948#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 1949#define SQLITE_REINDEX 27 /* Index Name NULL */ 1950#define SQLITE_ANALYZE 28 /* Table Name NULL */ 1951#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 1952#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 1953#define SQLITE_FUNCTION 31 /* NULL Function Name */ 1954#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 1955#define SQLITE_COPY 0 /* No longer used */ 1956 1957/* 1958** CAPI3REF: Tracing And Profiling Functions {H12280} <S60400> 1959** EXPERIMENTAL 1960** 1961** These routines register callback functions that can be used for 1962** tracing and profiling the execution of SQL statements. 1963** 1964** The callback function registered by sqlite3_trace() is invoked at 1965** various times when an SQL statement is being run by [sqlite3_step()]. 1966** The callback returns a UTF-8 rendering of the SQL statement text 1967** as the statement first begins executing. Additional callbacks occur 1968** as each triggered subprogram is entered. The callbacks for triggers 1969** contain a UTF-8 SQL comment that identifies the trigger. 1970** 1971** The callback function registered by sqlite3_profile() is invoked 1972** as each SQL statement finishes. The profile callback contains 1973** the original statement text and an estimate of wall-clock time 1974** of how long that statement took to run. 1975** 1976** Requirements: 1977** [H12281] [H12282] [H12283] [H12284] [H12285] [H12287] [H12288] [H12289] 1978** [H12290] 1979*/ 1980SQLITE_EXPERIMENTAL void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 1981SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 1982 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 1983 1984/* 1985** CAPI3REF: Query Progress Callbacks {H12910} <S60400> 1986** 1987** This routine configures a callback function - the 1988** progress callback - that is invoked periodically during long 1989** running calls to [sqlite3_exec()], [sqlite3_step()] and 1990** [sqlite3_get_table()]. An example use for this 1991** interface is to keep a GUI updated during a large query. 1992** 1993** If the progress callback returns non-zero, the operation is 1994** interrupted. This feature can be used to implement a 1995** "Cancel" button on a GUI progress dialog box. 1996** 1997** The progress handler must not do anything that will modify 1998** the database connection that invoked the progress handler. 1999** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2000** database connections for the meaning of "modify" in this paragraph. 2001** 2002** Requirements: 2003** [H12911] [H12912] [H12913] [H12914] [H12915] [H12916] [H12917] [H12918] 2004** 2005*/ 2006void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2007 2008/* 2009** CAPI3REF: Opening A New Database Connection {H12700} <S40200> 2010** 2011** These routines open an SQLite database file whose name is given by the 2012** filename argument. The filename argument is interpreted as UTF-8 for 2013** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2014** order for sqlite3_open16(). A [database connection] handle is usually 2015** returned in *ppDb, even if an error occurs. The only exception is that 2016** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2017** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2018** object. If the database is opened (and/or created) successfully, then 2019** [SQLITE_OK] is returned. Otherwise an [error code] is returned. The 2020** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2021** an English language description of the error. 2022** 2023** The default encoding for the database will be UTF-8 if 2024** sqlite3_open() or sqlite3_open_v2() is called and 2025** UTF-16 in the native byte order if sqlite3_open16() is used. 2026** 2027** Whether or not an error occurs when it is opened, resources 2028** associated with the [database connection] handle should be released by 2029** passing it to [sqlite3_close()] when it is no longer required. 2030** 2031** The sqlite3_open_v2() interface works like sqlite3_open() 2032** except that it accepts two additional parameters for additional control 2033** over the new database connection. The flags parameter can take one of 2034** the following three values, optionally combined with the 2035** [SQLITE_OPEN_NOMUTEX] or [SQLITE_OPEN_FULLMUTEX] flags: 2036** 2037** <dl> 2038** <dt>[SQLITE_OPEN_READONLY]</dt> 2039** <dd>The database is opened in read-only mode. If the database does not 2040** already exist, an error is returned.</dd> 2041** 2042** <dt>[SQLITE_OPEN_READWRITE]</dt> 2043** <dd>The database is opened for reading and writing if possible, or reading 2044** only if the file is write protected by the operating system. In either 2045** case the database must already exist, otherwise an error is returned.</dd> 2046** 2047** <dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2048** <dd>The database is opened for reading and writing, and is creates it if 2049** it does not already exist. This is the behavior that is always used for 2050** sqlite3_open() and sqlite3_open16().</dd> 2051** </dl> 2052** 2053** If the 3rd parameter to sqlite3_open_v2() is not one of the 2054** combinations shown above or one of the combinations shown above combined 2055** with the [SQLITE_OPEN_NOMUTEX] or [SQLITE_OPEN_FULLMUTEX] flags, 2056** then the behavior is undefined. 2057** 2058** If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2059** opens in the multi-thread [threading mode] as long as the single-thread 2060** mode has not been set at compile-time or start-time. If the 2061** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2062** in the serialized [threading mode] unless single-thread was 2063** previously selected at compile-time or start-time. 2064** 2065** If the filename is ":memory:", then a private, temporary in-memory database 2066** is created for the connection. This in-memory database will vanish when 2067** the database connection is closed. Future versions of SQLite might 2068** make use of additional special filenames that begin with the ":" character. 2069** It is recommended that when a database filename actually does begin with 2070** a ":" character you should prefix the filename with a pathname such as 2071** "./" to avoid ambiguity. 2072** 2073** If the filename is an empty string, then a private, temporary 2074** on-disk database will be created. This private database will be 2075** automatically deleted as soon as the database connection is closed. 2076** 2077** The fourth parameter to sqlite3_open_v2() is the name of the 2078** [sqlite3_vfs] object that defines the operating system interface that 2079** the new database connection should use. If the fourth parameter is 2080** a NULL pointer then the default [sqlite3_vfs] object is used. 2081** 2082** <b>Note to Windows users:</b> The encoding used for the filename argument 2083** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2084** codepage is currently defined. Filenames containing international 2085** characters must be converted to UTF-8 prior to passing them into 2086** sqlite3_open() or sqlite3_open_v2(). 2087** 2088** Requirements: 2089** [H12701] [H12702] [H12703] [H12704] [H12706] [H12707] [H12709] [H12711] 2090** [H12712] [H12713] [H12714] [H12717] [H12719] [H12721] [H12723] 2091*/ 2092int sqlite3_open( 2093 const char *filename, /* Database filename (UTF-8) */ 2094 sqlite3 **ppDb /* OUT: SQLite db handle */ 2095); 2096int sqlite3_open16( 2097 const void *filename, /* Database filename (UTF-16) */ 2098 sqlite3 **ppDb /* OUT: SQLite db handle */ 2099); 2100int sqlite3_open_v2( 2101 const char *filename, /* Database filename (UTF-8) */ 2102 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2103 int flags, /* Flags */ 2104 const char *zVfs /* Name of VFS module to use */ 2105); 2106 2107/* 2108** CAPI3REF: Error Codes And Messages {H12800} <S60200> 2109** 2110** The sqlite3_errcode() interface returns the numeric [result code] or 2111** [extended result code] for the most recent failed sqlite3_* API call 2112** associated with a [database connection]. If a prior API call failed 2113** but the most recent API call succeeded, the return value from 2114** sqlite3_errcode() is undefined. The sqlite3_extended_errcode() 2115** interface is the same except that it always returns the 2116** [extended result code] even when extended result codes are 2117** disabled. 2118** 2119** The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2120** text that describes the error, as either UTF-8 or UTF-16 respectively. 2121** Memory to hold the error message string is managed internally. 2122** The application does not need to worry about freeing the result. 2123** However, the error string might be overwritten or deallocated by 2124** subsequent calls to other SQLite interface functions. 2125** 2126** When the serialized [threading mode] is in use, it might be the 2127** case that a second error occurs on a separate thread in between 2128** the time of the first error and the call to these interfaces. 2129** When that happens, the second error will be reported since these 2130** interfaces always report the most recent result. To avoid 2131** this, each thread can obtain exclusive use of the [database connection] D 2132** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2133** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2134** all calls to the interfaces listed here are completed. 2135** 2136** If an interface fails with SQLITE_MISUSE, that means the interface 2137** was invoked incorrectly by the application. In that case, the 2138** error code and message may or may not be set. 2139** 2140** Requirements: 2141** [H12801] [H12802] [H12803] [H12807] [H12808] [H12809] 2142*/ 2143int sqlite3_errcode(sqlite3 *db); 2144int sqlite3_extended_errcode(sqlite3 *db); 2145const char *sqlite3_errmsg(sqlite3*); 2146const void *sqlite3_errmsg16(sqlite3*); 2147 2148/* 2149** CAPI3REF: SQL Statement Object {H13000} <H13010> 2150** KEYWORDS: {prepared statement} {prepared statements} 2151** 2152** An instance of this object represents a single SQL statement. 2153** This object is variously known as a "prepared statement" or a 2154** "compiled SQL statement" or simply as a "statement". 2155** 2156** The life of a statement object goes something like this: 2157** 2158** <ol> 2159** <li> Create the object using [sqlite3_prepare_v2()] or a related 2160** function. 2161** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2162** interfaces. 2163** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2164** <li> Reset the statement using [sqlite3_reset()] then go back 2165** to step 2. Do this zero or more times. 2166** <li> Destroy the object using [sqlite3_finalize()]. 2167** </ol> 2168** 2169** Refer to documentation on individual methods above for additional 2170** information. 2171*/ 2172typedef struct sqlite3_stmt sqlite3_stmt; 2173 2174/* 2175** CAPI3REF: Run-time Limits {H12760} <S20600> 2176** 2177** This interface allows the size of various constructs to be limited 2178** on a connection by connection basis. The first parameter is the 2179** [database connection] whose limit is to be set or queried. The 2180** second parameter is one of the [limit categories] that define a 2181** class of constructs to be size limited. The third parameter is the 2182** new limit for that construct. The function returns the old limit. 2183** 2184** If the new limit is a negative number, the limit is unchanged. 2185** For the limit category of SQLITE_LIMIT_XYZ there is a 2186** [limits | hard upper bound] 2187** set by a compile-time C preprocessor macro named 2188** [limits | SQLITE_MAX_XYZ]. 2189** (The "_LIMIT_" in the name is changed to "_MAX_".) 2190** Attempts to increase a limit above its hard upper bound are 2191** silently truncated to the hard upper limit. 2192** 2193** Run time limits are intended for use in applications that manage 2194** both their own internal database and also databases that are controlled 2195** by untrusted external sources. An example application might be a 2196** web browser that has its own databases for storing history and 2197** separate databases controlled by JavaScript applications downloaded 2198** off the Internet. The internal databases can be given the 2199** large, default limits. Databases managed by external sources can 2200** be given much smaller limits designed to prevent a denial of service 2201** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2202** interface to further control untrusted SQL. The size of the database 2203** created by an untrusted script can be contained using the 2204** [max_page_count] [PRAGMA]. 2205** 2206** New run-time limit categories may be added in future releases. 2207** 2208** Requirements: 2209** [H12762] [H12766] [H12769] 2210*/ 2211int sqlite3_limit(sqlite3*, int id, int newVal); 2212 2213/* 2214** CAPI3REF: Run-Time Limit Categories {H12790} <H12760> 2215** KEYWORDS: {limit category} {limit categories} 2216** 2217** These constants define various performance limits 2218** that can be lowered at run-time using [sqlite3_limit()]. 2219** The synopsis of the meanings of the various limits is shown below. 2220** Additional information is available at [limits | Limits in SQLite]. 2221** 2222** <dl> 2223** <dt>SQLITE_LIMIT_LENGTH</dt> 2224** <dd>The maximum size of any string or BLOB or table row.<dd> 2225** 2226** <dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2227** <dd>The maximum length of an SQL statement.</dd> 2228** 2229** <dt>SQLITE_LIMIT_COLUMN</dt> 2230** <dd>The maximum number of columns in a table definition or in the 2231** result set of a [SELECT] or the maximum number of columns in an index 2232** or in an ORDER BY or GROUP BY clause.</dd> 2233** 2234** <dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2235** <dd>The maximum depth of the parse tree on any expression.</dd> 2236** 2237** <dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2238** <dd>The maximum number of terms in a compound SELECT statement.</dd> 2239** 2240** <dt>SQLITE_LIMIT_VDBE_OP</dt> 2241** <dd>The maximum number of instructions in a virtual machine program 2242** used to implement an SQL statement.</dd> 2243** 2244** <dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2245** <dd>The maximum number of arguments on a function.</dd> 2246** 2247** <dt>SQLITE_LIMIT_ATTACHED</dt> 2248** <dd>The maximum number of [ATTACH | attached databases].</dd> 2249** 2250** <dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2251** <dd>The maximum length of the pattern argument to the [LIKE] or 2252** [GLOB] operators.</dd> 2253** 2254** <dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2255** <dd>The maximum number of variables in an SQL statement that can 2256** be bound.</dd> 2257** </dl> 2258*/ 2259#define SQLITE_LIMIT_LENGTH 0 2260#define SQLITE_LIMIT_SQL_LENGTH 1 2261#define SQLITE_LIMIT_COLUMN 2 2262#define SQLITE_LIMIT_EXPR_DEPTH 3 2263#define SQLITE_LIMIT_COMPOUND_SELECT 4 2264#define SQLITE_LIMIT_VDBE_OP 5 2265#define SQLITE_LIMIT_FUNCTION_ARG 6 2266#define SQLITE_LIMIT_ATTACHED 7 2267#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2268#define SQLITE_LIMIT_VARIABLE_NUMBER 9 2269 2270/* 2271** CAPI3REF: Compiling An SQL Statement {H13010} <S10000> 2272** KEYWORDS: {SQL statement compiler} 2273** 2274** To execute an SQL query, it must first be compiled into a byte-code 2275** program using one of these routines. 2276** 2277** The first argument, "db", is a [database connection] obtained from a 2278** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2279** [sqlite3_open16()]. The database connection must not have been closed. 2280** 2281** The second argument, "zSql", is the statement to be compiled, encoded 2282** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2283** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2284** use UTF-16. 2285** 2286** If the nByte argument is less than zero, then zSql is read up to the 2287** first zero terminator. If nByte is non-negative, then it is the maximum 2288** number of bytes read from zSql. When nByte is non-negative, the 2289** zSql string ends at either the first '\000' or '\u0000' character or 2290** the nByte-th byte, whichever comes first. If the caller knows 2291** that the supplied string is nul-terminated, then there is a small 2292** performance advantage to be gained by passing an nByte parameter that 2293** is equal to the number of bytes in the input string <i>including</i> 2294** the nul-terminator bytes. 2295** 2296** If pzTail is not NULL then *pzTail is made to point to the first byte 2297** past the end of the first SQL statement in zSql. These routines only 2298** compile the first statement in zSql, so *pzTail is left pointing to 2299** what remains uncompiled. 2300** 2301** *ppStmt is left pointing to a compiled [prepared statement] that can be 2302** executed using [sqlite3_step()]. If there is an error, *ppStmt is set 2303** to NULL. If the input text contains no SQL (if the input is an empty 2304** string or a comment) then *ppStmt is set to NULL. 2305** The calling procedure is responsible for deleting the compiled 2306** SQL statement using [sqlite3_finalize()] after it has finished with it. 2307** ppStmt may not be NULL. 2308** 2309** On success, [SQLITE_OK] is returned, otherwise an [error code] is returned. 2310** 2311** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2312** recommended for all new programs. The two older interfaces are retained 2313** for backwards compatibility, but their use is discouraged. 2314** In the "v2" interfaces, the prepared statement 2315** that is returned (the [sqlite3_stmt] object) contains a copy of the 2316** original SQL text. This causes the [sqlite3_step()] interface to 2317** behave a differently in two ways: 2318** 2319** <ol> 2320** <li> 2321** If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2322** always used to do, [sqlite3_step()] will automatically recompile the SQL 2323** statement and try to run it again. If the schema has changed in 2324** a way that makes the statement no longer valid, [sqlite3_step()] will still 2325** return [SQLITE_SCHEMA]. But unlike the legacy behavior, [SQLITE_SCHEMA] is 2326** now a fatal error. Calling [sqlite3_prepare_v2()] again will not make the 2327** error go away. Note: use [sqlite3_errmsg()] to find the text 2328** of the parsing error that results in an [SQLITE_SCHEMA] return. 2329** </li> 2330** 2331** <li> 2332** When an error occurs, [sqlite3_step()] will return one of the detailed 2333** [error codes] or [extended error codes]. The legacy behavior was that 2334** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2335** and you would have to make a second call to [sqlite3_reset()] in order 2336** to find the underlying cause of the problem. With the "v2" prepare 2337** interfaces, the underlying reason for the error is returned immediately. 2338** </li> 2339** </ol> 2340** 2341** Requirements: 2342** [H13011] [H13012] [H13013] [H13014] [H13015] [H13016] [H13019] [H13021] 2343** 2344*/ 2345int sqlite3_prepare( 2346 sqlite3 *db, /* Database handle */ 2347 const char *zSql, /* SQL statement, UTF-8 encoded */ 2348 int nByte, /* Maximum length of zSql in bytes. */ 2349 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2350 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2351); 2352int sqlite3_prepare_v2( 2353 sqlite3 *db, /* Database handle */ 2354 const char *zSql, /* SQL statement, UTF-8 encoded */ 2355 int nByte, /* Maximum length of zSql in bytes. */ 2356 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2357 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2358); 2359int sqlite3_prepare16( 2360 sqlite3 *db, /* Database handle */ 2361 const void *zSql, /* SQL statement, UTF-16 encoded */ 2362 int nByte, /* Maximum length of zSql in bytes. */ 2363 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2364 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2365); 2366int sqlite3_prepare16_v2( 2367 sqlite3 *db, /* Database handle */ 2368 const void *zSql, /* SQL statement, UTF-16 encoded */ 2369 int nByte, /* Maximum length of zSql in bytes. */ 2370 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2371 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2372); 2373 2374/* 2375** CAPI3REF: Retrieving Statement SQL {H13100} <H13000> 2376** 2377** This interface can be used to retrieve a saved copy of the original 2378** SQL text used to create a [prepared statement] if that statement was 2379** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2380** 2381** Requirements: 2382** [H13101] [H13102] [H13103] 2383*/ 2384const char *sqlite3_sql(sqlite3_stmt *pStmt); 2385 2386/* 2387** CAPI3REF: Dynamically Typed Value Object {H15000} <S20200> 2388** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 2389** 2390** SQLite uses the sqlite3_value object to represent all values 2391** that can be stored in a database table. SQLite uses dynamic typing 2392** for the values it stores. Values stored in sqlite3_value objects 2393** can be integers, floating point values, strings, BLOBs, or NULL. 2394** 2395** An sqlite3_value object may be either "protected" or "unprotected". 2396** Some interfaces require a protected sqlite3_value. Other interfaces 2397** will accept either a protected or an unprotected sqlite3_value. 2398** Every interface that accepts sqlite3_value arguments specifies 2399** whether or not it requires a protected sqlite3_value. 2400** 2401** The terms "protected" and "unprotected" refer to whether or not 2402** a mutex is held. A internal mutex is held for a protected 2403** sqlite3_value object but no mutex is held for an unprotected 2404** sqlite3_value object. If SQLite is compiled to be single-threaded 2405** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 2406** or if SQLite is run in one of reduced mutex modes 2407** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 2408** then there is no distinction between protected and unprotected 2409** sqlite3_value objects and they can be used interchangeably. However, 2410** for maximum code portability it is recommended that applications 2411** still make the distinction between between protected and unprotected 2412** sqlite3_value objects even when not strictly required. 2413** 2414** The sqlite3_value objects that are passed as parameters into the 2415** implementation of [application-defined SQL functions] are protected. 2416** The sqlite3_value object returned by 2417** [sqlite3_column_value()] is unprotected. 2418** Unprotected sqlite3_value objects may only be used with 2419** [sqlite3_result_value()] and [sqlite3_bind_value()]. 2420** The [sqlite3_value_blob | sqlite3_value_type()] family of 2421** interfaces require protected sqlite3_value objects. 2422*/ 2423typedef struct Mem sqlite3_value; 2424 2425/* 2426** CAPI3REF: SQL Function Context Object {H16001} <S20200> 2427** 2428** The context in which an SQL function executes is stored in an 2429** sqlite3_context object. A pointer to an sqlite3_context object 2430** is always first parameter to [application-defined SQL functions]. 2431** The application-defined SQL function implementation will pass this 2432** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 2433** [sqlite3_aggregate_context()], [sqlite3_user_data()], 2434** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 2435** and/or [sqlite3_set_auxdata()]. 2436*/ 2437typedef struct sqlite3_context sqlite3_context; 2438 2439/* 2440** CAPI3REF: Binding Values To Prepared Statements {H13500} <S70300> 2441** KEYWORDS: {host parameter} {host parameters} {host parameter name} 2442** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 2443** 2444** In the SQL strings input to [sqlite3_prepare_v2()] and its variants, 2445** literals may be replaced by a [parameter] in one of these forms: 2446** 2447** <ul> 2448** <li> ? 2449** <li> ?NNN 2450** <li> :VVV 2451** <li> @VVV 2452** <li> $VVV 2453** </ul> 2454** 2455** In the parameter forms shown above NNN is an integer literal, 2456** and VVV is an alpha-numeric parameter name. The values of these 2457** parameters (also called "host parameter names" or "SQL parameters") 2458** can be set using the sqlite3_bind_*() routines defined here. 2459** 2460** The first argument to the sqlite3_bind_*() routines is always 2461** a pointer to the [sqlite3_stmt] object returned from 2462** [sqlite3_prepare_v2()] or its variants. 2463** 2464** The second argument is the index of the SQL parameter to be set. 2465** The leftmost SQL parameter has an index of 1. When the same named 2466** SQL parameter is used more than once, second and subsequent 2467** occurrences have the same index as the first occurrence. 2468** The index for named parameters can be looked up using the 2469** [sqlite3_bind_parameter_index()] API if desired. The index 2470** for "?NNN" parameters is the value of NNN. 2471** The NNN value must be between 1 and the [sqlite3_limit()] 2472** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 2473** 2474** The third argument is the value to bind to the parameter. 2475** 2476** In those routines that have a fourth argument, its value is the 2477** number of bytes in the parameter. To be clear: the value is the 2478** number of <u>bytes</u> in the value, not the number of characters. 2479** If the fourth parameter is negative, the length of the string is 2480** the number of bytes up to the first zero terminator. 2481** 2482** The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 2483** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 2484** string after SQLite has finished with it. If the fifth argument is 2485** the special value [SQLITE_STATIC], then SQLite assumes that the 2486** information is in static, unmanaged space and does not need to be freed. 2487** If the fifth argument has the value [SQLITE_TRANSIENT], then 2488** SQLite makes its own private copy of the data immediately, before 2489** the sqlite3_bind_*() routine returns. 2490** 2491** The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 2492** is filled with zeroes. A zeroblob uses a fixed amount of memory 2493** (just an integer to hold its size) while it is being processed. 2494** Zeroblobs are intended to serve as placeholders for BLOBs whose 2495** content is later written using 2496** [sqlite3_blob_open | incremental BLOB I/O] routines. 2497** A negative value for the zeroblob results in a zero-length BLOB. 2498** 2499** The sqlite3_bind_*() routines must be called after 2500** [sqlite3_prepare_v2()] (and its variants) or [sqlite3_reset()] and 2501** before [sqlite3_step()]. 2502** Bindings are not cleared by the [sqlite3_reset()] routine. 2503** Unbound parameters are interpreted as NULL. 2504** 2505** These routines return [SQLITE_OK] on success or an error code if 2506** anything goes wrong. [SQLITE_RANGE] is returned if the parameter 2507** index is out of range. [SQLITE_NOMEM] is returned if malloc() fails. 2508** [SQLITE_MISUSE] might be returned if these routines are called on a 2509** virtual machine that is the wrong state or which has already been finalized. 2510** Detection of misuse is unreliable. Applications should not depend 2511** on SQLITE_MISUSE returns. SQLITE_MISUSE is intended to indicate a 2512** a logic error in the application. Future versions of SQLite might 2513** panic rather than return SQLITE_MISUSE. 2514** 2515** See also: [sqlite3_bind_parameter_count()], 2516** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 2517** 2518** Requirements: 2519** [H13506] [H13509] [H13512] [H13515] [H13518] [H13521] [H13524] [H13527] 2520** [H13530] [H13533] [H13536] [H13539] [H13542] [H13545] [H13548] [H13551] 2521** 2522*/ 2523int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 2524int sqlite3_bind_double(sqlite3_stmt*, int, double); 2525int sqlite3_bind_int(sqlite3_stmt*, int, int); 2526int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 2527int sqlite3_bind_null(sqlite3_stmt*, int); 2528int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 2529int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 2530int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 2531int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 2532 2533/* 2534** CAPI3REF: Number Of SQL Parameters {H13600} <S70300> 2535** 2536** This routine can be used to find the number of [SQL parameters] 2537** in a [prepared statement]. SQL parameters are tokens of the 2538** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 2539** placeholders for values that are [sqlite3_bind_blob | bound] 2540** to the parameters at a later time. 2541** 2542** This routine actually returns the index of the largest (rightmost) 2543** parameter. For all forms except ?NNN, this will correspond to the 2544** number of unique parameters. If parameters of the ?NNN are used, 2545** there may be gaps in the list. 2546** 2547** See also: [sqlite3_bind_blob|sqlite3_bind()], 2548** [sqlite3_bind_parameter_name()], and 2549** [sqlite3_bind_parameter_index()]. 2550** 2551** Requirements: 2552** [H13601] 2553*/ 2554int sqlite3_bind_parameter_count(sqlite3_stmt*); 2555 2556/* 2557** CAPI3REF: Name Of A Host Parameter {H13620} <S70300> 2558** 2559** This routine returns a pointer to the name of the n-th 2560** [SQL parameter] in a [prepared statement]. 2561** SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 2562** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 2563** respectively. 2564** In other words, the initial ":" or "$" or "@" or "?" 2565** is included as part of the name. 2566** Parameters of the form "?" without a following integer have no name 2567** and are also referred to as "anonymous parameters". 2568** 2569** The first host parameter has an index of 1, not 0. 2570** 2571** If the value n is out of range or if the n-th parameter is 2572** nameless, then NULL is returned. The returned string is 2573** always in UTF-8 encoding even if the named parameter was 2574** originally specified as UTF-16 in [sqlite3_prepare16()] or 2575** [sqlite3_prepare16_v2()]. 2576** 2577** See also: [sqlite3_bind_blob|sqlite3_bind()], 2578** [sqlite3_bind_parameter_count()], and 2579** [sqlite3_bind_parameter_index()]. 2580** 2581** Requirements: 2582** [H13621] 2583*/ 2584const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 2585 2586/* 2587** CAPI3REF: Index Of A Parameter With A Given Name {H13640} <S70300> 2588** 2589** Return the index of an SQL parameter given its name. The 2590** index value returned is suitable for use as the second 2591** parameter to [sqlite3_bind_blob|sqlite3_bind()]. A zero 2592** is returned if no matching parameter is found. The parameter 2593** name must be given in UTF-8 even if the original statement 2594** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 2595** 2596** See also: [sqlite3_bind_blob|sqlite3_bind()], 2597** [sqlite3_bind_parameter_count()], and 2598** [sqlite3_bind_parameter_index()]. 2599** 2600** Requirements: 2601** [H13641] 2602*/ 2603int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 2604 2605/* 2606** CAPI3REF: Reset All Bindings On A Prepared Statement {H13660} <S70300> 2607** 2608** Contrary to the intuition of many, [sqlite3_reset()] does not reset 2609** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 2610** Use this routine to reset all host parameters to NULL. 2611** 2612** Requirements: 2613** [H13661] 2614*/ 2615int sqlite3_clear_bindings(sqlite3_stmt*); 2616 2617/* 2618** CAPI3REF: Number Of Columns In A Result Set {H13710} <S10700> 2619** 2620** Return the number of columns in the result set returned by the 2621** [prepared statement]. This routine returns 0 if pStmt is an SQL 2622** statement that does not return data (for example an [UPDATE]). 2623** 2624** Requirements: 2625** [H13711] 2626*/ 2627int sqlite3_column_count(sqlite3_stmt *pStmt); 2628 2629/* 2630** CAPI3REF: Column Names In A Result Set {H13720} <S10700> 2631** 2632** These routines return the name assigned to a particular column 2633** in the result set of a [SELECT] statement. The sqlite3_column_name() 2634** interface returns a pointer to a zero-terminated UTF-8 string 2635** and sqlite3_column_name16() returns a pointer to a zero-terminated 2636** UTF-16 string. The first parameter is the [prepared statement] 2637** that implements the [SELECT] statement. The second parameter is the 2638** column number. The leftmost column is number 0. 2639** 2640** The returned string pointer is valid until either the [prepared statement] 2641** is destroyed by [sqlite3_finalize()] or until the next call to 2642** sqlite3_column_name() or sqlite3_column_name16() on the same column. 2643** 2644** If sqlite3_malloc() fails during the processing of either routine 2645** (for example during a conversion from UTF-8 to UTF-16) then a 2646** NULL pointer is returned. 2647** 2648** The name of a result column is the value of the "AS" clause for 2649** that column, if there is an AS clause. If there is no AS clause 2650** then the name of the column is unspecified and may change from 2651** one release of SQLite to the next. 2652** 2653** Requirements: 2654** [H13721] [H13723] [H13724] [H13725] [H13726] [H13727] 2655*/ 2656const char *sqlite3_column_name(sqlite3_stmt*, int N); 2657const void *sqlite3_column_name16(sqlite3_stmt*, int N); 2658 2659/* 2660** CAPI3REF: Source Of Data In A Query Result {H13740} <S10700> 2661** 2662** These routines provide a means to determine what column of what 2663** table in which database a result of a [SELECT] statement comes from. 2664** The name of the database or table or column can be returned as 2665** either a UTF-8 or UTF-16 string. The _database_ routines return 2666** the database name, the _table_ routines return the table name, and 2667** the origin_ routines return the column name. 2668** The returned string is valid until the [prepared statement] is destroyed 2669** using [sqlite3_finalize()] or until the same information is requested 2670** again in a different encoding. 2671** 2672** The names returned are the original un-aliased names of the 2673** database, table, and column. 2674** 2675** The first argument to the following calls is a [prepared statement]. 2676** These functions return information about the Nth column returned by 2677** the statement, where N is the second function argument. 2678** 2679** If the Nth column returned by the statement is an expression or 2680** subquery and is not a column value, then all of these functions return 2681** NULL. These routine might also return NULL if a memory allocation error 2682** occurs. Otherwise, they return the name of the attached database, table 2683** and column that query result column was extracted from. 2684** 2685** As with all other SQLite APIs, those postfixed with "16" return 2686** UTF-16 encoded strings, the other functions return UTF-8. {END} 2687** 2688** These APIs are only available if the library was compiled with the 2689** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 2690** 2691** {A13751} 2692** If two or more threads call one or more of these routines against the same 2693** prepared statement and column at the same time then the results are 2694** undefined. 2695** 2696** Requirements: 2697** [H13741] [H13742] [H13743] [H13744] [H13745] [H13746] [H13748] 2698** 2699** If two or more threads call one or more 2700** [sqlite3_column_database_name | column metadata interfaces] 2701** for the same [prepared statement] and result column 2702** at the same time then the results are undefined. 2703*/ 2704const char *sqlite3_column_database_name(sqlite3_stmt*,int); 2705const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 2706const char *sqlite3_column_table_name(sqlite3_stmt*,int); 2707const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 2708const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 2709const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 2710 2711/* 2712** CAPI3REF: Declared Datatype Of A Query Result {H13760} <S10700> 2713** 2714** The first parameter is a [prepared statement]. 2715** If this statement is a [SELECT] statement and the Nth column of the 2716** returned result set of that [SELECT] is a table column (not an 2717** expression or subquery) then the declared type of the table 2718** column is returned. If the Nth column of the result set is an 2719** expression or subquery, then a NULL pointer is returned. 2720** The returned string is always UTF-8 encoded. {END} 2721** 2722** For example, given the database schema: 2723** 2724** CREATE TABLE t1(c1 VARIANT); 2725** 2726** and the following statement to be compiled: 2727** 2728** SELECT c1 + 1, c1 FROM t1; 2729** 2730** this routine would return the string "VARIANT" for the second result 2731** column (i==1), and a NULL pointer for the first result column (i==0). 2732** 2733** SQLite uses dynamic run-time typing. So just because a column 2734** is declared to contain a particular type does not mean that the 2735** data stored in that column is of the declared type. SQLite is 2736** strongly typed, but the typing is dynamic not static. Type 2737** is associated with individual values, not with the containers 2738** used to hold those values. 2739** 2740** Requirements: 2741** [H13761] [H13762] [H13763] 2742*/ 2743const char *sqlite3_column_decltype(sqlite3_stmt*,int); 2744const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 2745 2746/* 2747** CAPI3REF: Evaluate An SQL Statement {H13200} <S10000> 2748** 2749** After a [prepared statement] has been prepared using either 2750** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 2751** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 2752** must be called one or more times to evaluate the statement. 2753** 2754** The details of the behavior of the sqlite3_step() interface depend 2755** on whether the statement was prepared using the newer "v2" interface 2756** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 2757** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 2758** new "v2" interface is recommended for new applications but the legacy 2759** interface will continue to be supported. 2760** 2761** In the legacy interface, the return value will be either [SQLITE_BUSY], 2762** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 2763** With the "v2" interface, any of the other [result codes] or 2764** [extended result codes] might be returned as well. 2765** 2766** [SQLITE_BUSY] means that the database engine was unable to acquire the 2767** database locks it needs to do its job. If the statement is a [COMMIT] 2768** or occurs outside of an explicit transaction, then you can retry the 2769** statement. If the statement is not a [COMMIT] and occurs within a 2770** explicit transaction then you should rollback the transaction before 2771** continuing. 2772** 2773** [SQLITE_DONE] means that the statement has finished executing 2774** successfully. sqlite3_step() should not be called again on this virtual 2775** machine without first calling [sqlite3_reset()] to reset the virtual 2776** machine back to its initial state. 2777** 2778** If the SQL statement being executed returns any data, then [SQLITE_ROW] 2779** is returned each time a new row of data is ready for processing by the 2780** caller. The values may be accessed using the [column access functions]. 2781** sqlite3_step() is called again to retrieve the next row of data. 2782** 2783** [SQLITE_ERROR] means that a run-time error (such as a constraint 2784** violation) has occurred. sqlite3_step() should not be called again on 2785** the VM. More information may be found by calling [sqlite3_errmsg()]. 2786** With the legacy interface, a more specific error code (for example, 2787** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 2788** can be obtained by calling [sqlite3_reset()] on the 2789** [prepared statement]. In the "v2" interface, 2790** the more specific error code is returned directly by sqlite3_step(). 2791** 2792** [SQLITE_MISUSE] means that the this routine was called inappropriately. 2793** Perhaps it was called on a [prepared statement] that has 2794** already been [sqlite3_finalize | finalized] or on one that had 2795** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 2796** be the case that the same database connection is being used by two or 2797** more threads at the same moment in time. 2798** 2799** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 2800** API always returns a generic error code, [SQLITE_ERROR], following any 2801** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 2802** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 2803** specific [error codes] that better describes the error. 2804** We admit that this is a goofy design. The problem has been fixed 2805** with the "v2" interface. If you prepare all of your SQL statements 2806** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 2807** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 2808** then the more specific [error codes] are returned directly 2809** by sqlite3_step(). The use of the "v2" interface is recommended. 2810** 2811** Requirements: 2812** [H13202] [H15304] [H15306] [H15308] [H15310] 2813*/ 2814int sqlite3_step(sqlite3_stmt*); 2815 2816/* 2817** CAPI3REF: Number of columns in a result set {H13770} <S10700> 2818** 2819** Returns the number of values in the current row of the result set. 2820** 2821** Requirements: 2822** [H13771] [H13772] 2823*/ 2824int sqlite3_data_count(sqlite3_stmt *pStmt); 2825 2826/* 2827** CAPI3REF: Fundamental Datatypes {H10265} <S10110><S10120> 2828** KEYWORDS: SQLITE_TEXT 2829** 2830** {H10266} Every value in SQLite has one of five fundamental datatypes: 2831** 2832** <ul> 2833** <li> 64-bit signed integer 2834** <li> 64-bit IEEE floating point number 2835** <li> string 2836** <li> BLOB 2837** <li> NULL 2838** </ul> {END} 2839** 2840** These constants are codes for each of those types. 2841** 2842** Note that the SQLITE_TEXT constant was also used in SQLite version 2 2843** for a completely different meaning. Software that links against both 2844** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 2845** SQLITE_TEXT. 2846*/ 2847#define SQLITE_INTEGER 1 2848#define SQLITE_FLOAT 2 2849#define SQLITE_BLOB 4 2850#define SQLITE_NULL 5 2851#ifdef SQLITE_TEXT 2852# undef SQLITE_TEXT 2853#else 2854# define SQLITE_TEXT 3 2855#endif 2856#define SQLITE3_TEXT 3 2857 2858/* 2859** CAPI3REF: Result Values From A Query {H13800} <S10700> 2860** KEYWORDS: {column access functions} 2861** 2862** These routines form the "result set query" interface. 2863** 2864** These routines return information about a single column of the current 2865** result row of a query. In every case the first argument is a pointer 2866** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 2867** that was returned from [sqlite3_prepare_v2()] or one of its variants) 2868** and the second argument is the index of the column for which information 2869** should be returned. The leftmost column of the result set has the index 0. 2870** 2871** If the SQL statement does not currently point to a valid row, or if the 2872** column index is out of range, the result is undefined. 2873** These routines may only be called when the most recent call to 2874** [sqlite3_step()] has returned [SQLITE_ROW] and neither 2875** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 2876** If any of these routines are called after [sqlite3_reset()] or 2877** [sqlite3_finalize()] or after [sqlite3_step()] has returned 2878** something other than [SQLITE_ROW], the results are undefined. 2879** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 2880** are called from a different thread while any of these routines 2881** are pending, then the results are undefined. 2882** 2883** The sqlite3_column_type() routine returns the 2884** [SQLITE_INTEGER | datatype code] for the initial data type 2885** of the result column. The returned value is one of [SQLITE_INTEGER], 2886** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 2887** returned by sqlite3_column_type() is only meaningful if no type 2888** conversions have occurred as described below. After a type conversion, 2889** the value returned by sqlite3_column_type() is undefined. Future 2890** versions of SQLite may change the behavior of sqlite3_column_type() 2891** following a type conversion. 2892** 2893** If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 2894** routine returns the number of bytes in that BLOB or string. 2895** If the result is a UTF-16 string, then sqlite3_column_bytes() converts 2896** the string to UTF-8 and then returns the number of bytes. 2897** If the result is a numeric value then sqlite3_column_bytes() uses 2898** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 2899** the number of bytes in that string. 2900** The value returned does not include the zero terminator at the end 2901** of the string. For clarity: the value returned is the number of 2902** bytes in the string, not the number of characters. 2903** 2904** Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 2905** even empty strings, are always zero terminated. The return 2906** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary 2907** pointer, possibly even a NULL pointer. 2908** 2909** The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes() 2910** but leaves the result in UTF-16 in native byte order instead of UTF-8. 2911** The zero terminator is not included in this count. 2912** 2913** The object returned by [sqlite3_column_value()] is an 2914** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 2915** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 2916** If the [unprotected sqlite3_value] object returned by 2917** [sqlite3_column_value()] is used in any other way, including calls 2918** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 2919** or [sqlite3_value_bytes()], then the behavior is undefined. 2920** 2921** These routines attempt to convert the value where appropriate. For 2922** example, if the internal representation is FLOAT and a text result 2923** is requested, [sqlite3_snprintf()] is used internally to perform the 2924** conversion automatically. The following table details the conversions 2925** that are applied: 2926** 2927** <blockquote> 2928** <table border="1"> 2929** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 2930** 2931** <tr><td> NULL <td> INTEGER <td> Result is 0 2932** <tr><td> NULL <td> FLOAT <td> Result is 0.0 2933** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 2934** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 2935** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 2936** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 2937** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 2938** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 2939** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 2940** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 2941** <tr><td> TEXT <td> INTEGER <td> Use atoi() 2942** <tr><td> TEXT <td> FLOAT <td> Use atof() 2943** <tr><td> TEXT <td> BLOB <td> No change 2944** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 2945** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 2946** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 2947** </table> 2948** </blockquote> 2949** 2950** The table above makes reference to standard C library functions atoi() 2951** and atof(). SQLite does not really use these functions. It has its 2952** own equivalent internal routines. The atoi() and atof() names are 2953** used in the table for brevity and because they are familiar to most 2954** C programmers. 2955** 2956** Note that when type conversions occur, pointers returned by prior 2957** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 2958** sqlite3_column_text16() may be invalidated. 2959** Type conversions and pointer invalidations might occur 2960** in the following cases: 2961** 2962** <ul> 2963** <li> The initial content is a BLOB and sqlite3_column_text() or 2964** sqlite3_column_text16() is called. A zero-terminator might 2965** need to be added to the string.</li> 2966** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 2967** sqlite3_column_text16() is called. The content must be converted 2968** to UTF-16.</li> 2969** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 2970** sqlite3_column_text() is called. The content must be converted 2971** to UTF-8.</li> 2972** </ul> 2973** 2974** Conversions between UTF-16be and UTF-16le are always done in place and do 2975** not invalidate a prior pointer, though of course the content of the buffer 2976** that the prior pointer points to will have been modified. Other kinds 2977** of conversion are done in place when it is possible, but sometimes they 2978** are not possible and in those cases prior pointers are invalidated. 2979** 2980** The safest and easiest to remember policy is to invoke these routines 2981** in one of the following ways: 2982** 2983** <ul> 2984** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 2985** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 2986** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 2987** </ul> 2988** 2989** In other words, you should call sqlite3_column_text(), 2990** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 2991** into the desired format, then invoke sqlite3_column_bytes() or 2992** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 2993** to sqlite3_column_text() or sqlite3_column_blob() with calls to 2994** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 2995** with calls to sqlite3_column_bytes(). 2996** 2997** The pointers returned are valid until a type conversion occurs as 2998** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 2999** [sqlite3_finalize()] is called. The memory space used to hold strings 3000** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3001** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3002** [sqlite3_free()]. 3003** 3004** If a memory allocation error occurs during the evaluation of any 3005** of these routines, a default value is returned. The default value 3006** is either the integer 0, the floating point number 0.0, or a NULL 3007** pointer. Subsequent calls to [sqlite3_errcode()] will return 3008** [SQLITE_NOMEM]. 3009** 3010** Requirements: 3011** [H13803] [H13806] [H13809] [H13812] [H13815] [H13818] [H13821] [H13824] 3012** [H13827] [H13830] 3013*/ 3014const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3015int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3016int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3017double sqlite3_column_double(sqlite3_stmt*, int iCol); 3018int sqlite3_column_int(sqlite3_stmt*, int iCol); 3019sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3020const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3021const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3022int sqlite3_column_type(sqlite3_stmt*, int iCol); 3023sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3024 3025/* 3026** CAPI3REF: Destroy A Prepared Statement Object {H13300} <S70300><S30100> 3027** 3028** The sqlite3_finalize() function is called to delete a [prepared statement]. 3029** If the statement was executed successfully or not executed at all, then 3030** SQLITE_OK is returned. If execution of the statement failed then an 3031** [error code] or [extended error code] is returned. 3032** 3033** This routine can be called at any point during the execution of the 3034** [prepared statement]. If the virtual machine has not 3035** completed execution when this routine is called, that is like 3036** encountering an error or an [sqlite3_interrupt | interrupt]. 3037** Incomplete updates may be rolled back and transactions canceled, 3038** depending on the circumstances, and the 3039** [error code] returned will be [SQLITE_ABORT]. 3040** 3041** Requirements: 3042** [H11302] [H11304] 3043*/ 3044int sqlite3_finalize(sqlite3_stmt *pStmt); 3045 3046/* 3047** CAPI3REF: Reset A Prepared Statement Object {H13330} <S70300> 3048** 3049** The sqlite3_reset() function is called to reset a [prepared statement] 3050** object back to its initial state, ready to be re-executed. 3051** Any SQL statement variables that had values bound to them using 3052** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3053** Use [sqlite3_clear_bindings()] to reset the bindings. 3054** 3055** {H11332} The [sqlite3_reset(S)] interface resets the [prepared statement] S 3056** back to the beginning of its program. 3057** 3058** {H11334} If the most recent call to [sqlite3_step(S)] for the 3059** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3060** or if [sqlite3_step(S)] has never before been called on S, 3061** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3062** 3063** {H11336} If the most recent call to [sqlite3_step(S)] for the 3064** [prepared statement] S indicated an error, then 3065** [sqlite3_reset(S)] returns an appropriate [error code]. 3066** 3067** {H11338} The [sqlite3_reset(S)] interface does not change the values 3068** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3069*/ 3070int sqlite3_reset(sqlite3_stmt *pStmt); 3071 3072/* 3073** CAPI3REF: Create Or Redefine SQL Functions {H16100} <S20200> 3074** KEYWORDS: {function creation routines} 3075** KEYWORDS: {application-defined SQL function} 3076** KEYWORDS: {application-defined SQL functions} 3077** 3078** These two functions (collectively known as "function creation routines") 3079** are used to add SQL functions or aggregates or to redefine the behavior 3080** of existing SQL functions or aggregates. The only difference between the 3081** two is that the second parameter, the name of the (scalar) function or 3082** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16 3083** for sqlite3_create_function16(). 3084** 3085** The first parameter is the [database connection] to which the SQL 3086** function is to be added. If a single program uses more than one database 3087** connection internally, then SQL functions must be added individually to 3088** each database connection. 3089** 3090** The second parameter is the name of the SQL function to be created or 3091** redefined. The length of the name is limited to 255 bytes, exclusive of 3092** the zero-terminator. Note that the name length limit is in bytes, not 3093** characters. Any attempt to create a function with a longer name 3094** will result in [SQLITE_ERROR] being returned. 3095** 3096** The third parameter (nArg) 3097** is the number of arguments that the SQL function or 3098** aggregate takes. If this parameter is -1, then the SQL function or 3099** aggregate may take any number of arguments between 0 and the limit 3100** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3101** parameter is less than -1 or greater than 127 then the behavior is 3102** undefined. 3103** 3104** The fourth parameter, eTextRep, specifies what 3105** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3106** its parameters. Any SQL function implementation should be able to work 3107** work with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3108** more efficient with one encoding than another. It is allowed to 3109** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3110** times with the same function but with different values of eTextRep. 3111** When multiple implementations of the same function are available, SQLite 3112** will pick the one that involves the least amount of data conversion. 3113** If there is only a single implementation which does not care what text 3114** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3115** 3116** The fifth parameter is an arbitrary pointer. The implementation of the 3117** function can gain access to this pointer using [sqlite3_user_data()]. 3118** 3119** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are 3120** pointers to C-language functions that implement the SQL function or 3121** aggregate. A scalar SQL function requires an implementation of the xFunc 3122** callback only, NULL pointers should be passed as the xStep and xFinal 3123** parameters. An aggregate SQL function requires an implementation of xStep 3124** and xFinal and NULL should be passed for xFunc. To delete an existing 3125** SQL function or aggregate, pass NULL for all three function callbacks. 3126** 3127** It is permitted to register multiple implementations of the same 3128** functions with the same name but with either differing numbers of 3129** arguments or differing preferred text encodings. SQLite will use 3130** the implementation most closely matches the way in which the 3131** SQL function is used. A function implementation with a non-negative 3132** nArg parameter is a better match than a function implementation with 3133** a negative nArg. A function where the preferred text encoding 3134** matches the database encoding is a better 3135** match than a function where the encoding is different. 3136** A function where the encoding difference is between UTF16le and UTF16be 3137** is a closer match than a function where the encoding difference is 3138** between UTF8 and UTF16. 3139** 3140** Built-in functions may be overloaded by new application-defined functions. 3141** The first application-defined function with a given name overrides all 3142** built-in functions in the same [database connection] with the same name. 3143** Subsequent application-defined functions of the same name only override 3144** prior application-defined functions that are an exact match for the 3145** number of parameters and preferred encoding. 3146** 3147** An application-defined function is permitted to call other 3148** SQLite interfaces. However, such calls must not 3149** close the database connection nor finalize or reset the prepared 3150** statement in which the function is running. 3151** 3152** Requirements: 3153** [H16103] [H16106] [H16109] [H16112] [H16118] [H16121] [H16127] 3154** [H16130] [H16133] [H16136] [H16139] [H16142] 3155*/ 3156int sqlite3_create_function( 3157 sqlite3 *db, 3158 const char *zFunctionName, 3159 int nArg, 3160 int eTextRep, 3161 void *pApp, 3162 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3163 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3164 void (*xFinal)(sqlite3_context*) 3165); 3166int sqlite3_create_function16( 3167 sqlite3 *db, 3168 const void *zFunctionName, 3169 int nArg, 3170 int eTextRep, 3171 void *pApp, 3172 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3173 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3174 void (*xFinal)(sqlite3_context*) 3175); 3176 3177/* 3178** CAPI3REF: Text Encodings {H10267} <S50200> <H16100> 3179** 3180** These constant define integer codes that represent the various 3181** text encodings supported by SQLite. 3182*/ 3183#define SQLITE_UTF8 1 3184#define SQLITE_UTF16LE 2 3185#define SQLITE_UTF16BE 3 3186#define SQLITE_UTF16 4 /* Use native byte order */ 3187#define SQLITE_ANY 5 /* sqlite3_create_function only */ 3188#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3189 3190/* 3191** CAPI3REF: Deprecated Functions 3192** DEPRECATED 3193** 3194** These functions are [deprecated]. In order to maintain 3195** backwards compatibility with older code, these functions continue 3196** to be supported. However, new applications should avoid 3197** the use of these functions. To help encourage people to avoid 3198** using these functions, we are not going to tell you what they do. 3199*/ 3200#ifndef SQLITE_OMIT_DEPRECATED 3201SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3202SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3203SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3204SQLITE_DEPRECATED int sqlite3_global_recover(void); 3205SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3206SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3207#endif 3208 3209/* 3210** CAPI3REF: Obtaining SQL Function Parameter Values {H15100} <S20200> 3211** 3212** The C-language implementation of SQL functions and aggregates uses 3213** this set of interface routines to access the parameter values on 3214** the function or aggregate. 3215** 3216** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3217** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3218** define callbacks that implement the SQL functions and aggregates. 3219** The 4th parameter to these callbacks is an array of pointers to 3220** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3221** each parameter to the SQL function. These routines are used to 3222** extract values from the [sqlite3_value] objects. 3223** 3224** These routines work only with [protected sqlite3_value] objects. 3225** Any attempt to use these routines on an [unprotected sqlite3_value] 3226** object results in undefined behavior. 3227** 3228** These routines work just like the corresponding [column access functions] 3229** except that these routines take a single [protected sqlite3_value] object 3230** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3231** 3232** The sqlite3_value_text16() interface extracts a UTF-16 string 3233** in the native byte-order of the host machine. The 3234** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3235** extract UTF-16 strings as big-endian and little-endian respectively. 3236** 3237** The sqlite3_value_numeric_type() interface attempts to apply 3238** numeric affinity to the value. This means that an attempt is 3239** made to convert the value to an integer or floating point. If 3240** such a conversion is possible without loss of information (in other 3241** words, if the value is a string that looks like a number) 3242** then the conversion is performed. Otherwise no conversion occurs. 3243** The [SQLITE_INTEGER | datatype] after conversion is returned. 3244** 3245** Please pay particular attention to the fact that the pointer returned 3246** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3247** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3248** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3249** or [sqlite3_value_text16()]. 3250** 3251** These routines must be called from the same thread as 3252** the SQL function that supplied the [sqlite3_value*] parameters. 3253** 3254** Requirements: 3255** [H15103] [H15106] [H15109] [H15112] [H15115] [H15118] [H15121] [H15124] 3256** [H15127] [H15130] [H15133] [H15136] 3257*/ 3258const void *sqlite3_value_blob(sqlite3_value*); 3259int sqlite3_value_bytes(sqlite3_value*); 3260int sqlite3_value_bytes16(sqlite3_value*); 3261double sqlite3_value_double(sqlite3_value*); 3262int sqlite3_value_int(sqlite3_value*); 3263sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3264const unsigned char *sqlite3_value_text(sqlite3_value*); 3265const void *sqlite3_value_text16(sqlite3_value*); 3266const void *sqlite3_value_text16le(sqlite3_value*); 3267const void *sqlite3_value_text16be(sqlite3_value*); 3268int sqlite3_value_type(sqlite3_value*); 3269int sqlite3_value_numeric_type(sqlite3_value*); 3270 3271/* 3272** CAPI3REF: Obtain Aggregate Function Context {H16210} <S20200> 3273** 3274** The implementation of aggregate SQL functions use this routine to allocate 3275** a structure for storing their state. 3276** 3277** The first time the sqlite3_aggregate_context() routine is called for a 3278** particular aggregate, SQLite allocates nBytes of memory, zeroes out that 3279** memory, and returns a pointer to it. On second and subsequent calls to 3280** sqlite3_aggregate_context() for the same aggregate function index, 3281** the same buffer is returned. The implementation of the aggregate can use 3282** the returned buffer to accumulate data. 3283** 3284** SQLite automatically frees the allocated buffer when the aggregate 3285** query concludes. 3286** 3287** The first parameter should be a copy of the 3288** [sqlite3_context | SQL function context] that is the first parameter 3289** to the callback routine that implements the aggregate function. 3290** 3291** This routine must be called from the same thread in which 3292** the aggregate SQL function is running. 3293** 3294** Requirements: 3295** [H16211] [H16213] [H16215] [H16217] 3296*/ 3297void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 3298 3299/* 3300** CAPI3REF: User Data For Functions {H16240} <S20200> 3301** 3302** The sqlite3_user_data() interface returns a copy of 3303** the pointer that was the pUserData parameter (the 5th parameter) 3304** of the [sqlite3_create_function()] 3305** and [sqlite3_create_function16()] routines that originally 3306** registered the application defined function. {END} 3307** 3308** This routine must be called from the same thread in which 3309** the application-defined function is running. 3310** 3311** Requirements: 3312** [H16243] 3313*/ 3314void *sqlite3_user_data(sqlite3_context*); 3315 3316/* 3317** CAPI3REF: Database Connection For Functions {H16250} <S60600><S20200> 3318** 3319** The sqlite3_context_db_handle() interface returns a copy of 3320** the pointer to the [database connection] (the 1st parameter) 3321** of the [sqlite3_create_function()] 3322** and [sqlite3_create_function16()] routines that originally 3323** registered the application defined function. 3324** 3325** Requirements: 3326** [H16253] 3327*/ 3328sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 3329 3330/* 3331** CAPI3REF: Function Auxiliary Data {H16270} <S20200> 3332** 3333** The following two functions may be used by scalar SQL functions to 3334** associate metadata with argument values. If the same value is passed to 3335** multiple invocations of the same SQL function during query execution, under 3336** some circumstances the associated metadata may be preserved. This may 3337** be used, for example, to add a regular-expression matching scalar 3338** function. The compiled version of the regular expression is stored as 3339** metadata associated with the SQL value passed as the regular expression 3340** pattern. The compiled regular expression can be reused on multiple 3341** invocations of the same function so that the original pattern string 3342** does not need to be recompiled on each invocation. 3343** 3344** The sqlite3_get_auxdata() interface returns a pointer to the metadata 3345** associated by the sqlite3_set_auxdata() function with the Nth argument 3346** value to the application-defined function. If no metadata has been ever 3347** been set for the Nth argument of the function, or if the corresponding 3348** function parameter has changed since the meta-data was set, 3349** then sqlite3_get_auxdata() returns a NULL pointer. 3350** 3351** The sqlite3_set_auxdata() interface saves the metadata 3352** pointed to by its 3rd parameter as the metadata for the N-th 3353** argument of the application-defined function. Subsequent 3354** calls to sqlite3_get_auxdata() might return this data, if it has 3355** not been destroyed. 3356** If it is not NULL, SQLite will invoke the destructor 3357** function given by the 4th parameter to sqlite3_set_auxdata() on 3358** the metadata when the corresponding function parameter changes 3359** or when the SQL statement completes, whichever comes first. 3360** 3361** SQLite is free to call the destructor and drop metadata on any 3362** parameter of any function at any time. The only guarantee is that 3363** the destructor will be called before the metadata is dropped. 3364** 3365** In practice, metadata is preserved between function calls for 3366** expressions that are constant at compile time. This includes literal 3367** values and SQL variables. 3368** 3369** These routines must be called from the same thread in which 3370** the SQL function is running. 3371** 3372** Requirements: 3373** [H16272] [H16274] [H16276] [H16277] [H16278] [H16279] 3374*/ 3375void *sqlite3_get_auxdata(sqlite3_context*, int N); 3376void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 3377 3378 3379/* 3380** CAPI3REF: Constants Defining Special Destructor Behavior {H10280} <S30100> 3381** 3382** These are special values for the destructor that is passed in as the 3383** final argument to routines like [sqlite3_result_blob()]. If the destructor 3384** argument is SQLITE_STATIC, it means that the content pointer is constant 3385** and will never change. It does not need to be destroyed. The 3386** SQLITE_TRANSIENT value means that the content will likely change in 3387** the near future and that SQLite should make its own private copy of 3388** the content before returning. 3389** 3390** The typedef is necessary to work around problems in certain 3391** C++ compilers. See ticket #2191. 3392*/ 3393typedef void (*sqlite3_destructor_type)(void*); 3394#define SQLITE_STATIC ((sqlite3_destructor_type)0) 3395#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 3396 3397/* 3398** CAPI3REF: Setting The Result Of An SQL Function {H16400} <S20200> 3399** 3400** These routines are used by the xFunc or xFinal callbacks that 3401** implement SQL functions and aggregates. See 3402** [sqlite3_create_function()] and [sqlite3_create_function16()] 3403** for additional information. 3404** 3405** These functions work very much like the [parameter binding] family of 3406** functions used to bind values to host parameters in prepared statements. 3407** Refer to the [SQL parameter] documentation for additional information. 3408** 3409** The sqlite3_result_blob() interface sets the result from 3410** an application-defined function to be the BLOB whose content is pointed 3411** to by the second parameter and which is N bytes long where N is the 3412** third parameter. 3413** 3414** The sqlite3_result_zeroblob() interfaces set the result of 3415** the application-defined function to be a BLOB containing all zero 3416** bytes and N bytes in size, where N is the value of the 2nd parameter. 3417** 3418** The sqlite3_result_double() interface sets the result from 3419** an application-defined function to be a floating point value specified 3420** by its 2nd argument. 3421** 3422** The sqlite3_result_error() and sqlite3_result_error16() functions 3423** cause the implemented SQL function to throw an exception. 3424** SQLite uses the string pointed to by the 3425** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 3426** as the text of an error message. SQLite interprets the error 3427** message string from sqlite3_result_error() as UTF-8. SQLite 3428** interprets the string from sqlite3_result_error16() as UTF-16 in native 3429** byte order. If the third parameter to sqlite3_result_error() 3430** or sqlite3_result_error16() is negative then SQLite takes as the error 3431** message all text up through the first zero character. 3432** If the third parameter to sqlite3_result_error() or 3433** sqlite3_result_error16() is non-negative then SQLite takes that many 3434** bytes (not characters) from the 2nd parameter as the error message. 3435** The sqlite3_result_error() and sqlite3_result_error16() 3436** routines make a private copy of the error message text before 3437** they return. Hence, the calling function can deallocate or 3438** modify the text after they return without harm. 3439** The sqlite3_result_error_code() function changes the error code 3440** returned by SQLite as a result of an error in a function. By default, 3441** the error code is SQLITE_ERROR. A subsequent call to sqlite3_result_error() 3442** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 3443** 3444** The sqlite3_result_toobig() interface causes SQLite to throw an error 3445** indicating that a string or BLOB is to long to represent. 3446** 3447** The sqlite3_result_nomem() interface causes SQLite to throw an error 3448** indicating that a memory allocation failed. 3449** 3450** The sqlite3_result_int() interface sets the return value 3451** of the application-defined function to be the 32-bit signed integer 3452** value given in the 2nd argument. 3453** The sqlite3_result_int64() interface sets the return value 3454** of the application-defined function to be the 64-bit signed integer 3455** value given in the 2nd argument. 3456** 3457** The sqlite3_result_null() interface sets the return value 3458** of the application-defined function to be NULL. 3459** 3460** The sqlite3_result_text(), sqlite3_result_text16(), 3461** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 3462** set the return value of the application-defined function to be 3463** a text string which is represented as UTF-8, UTF-16 native byte order, 3464** UTF-16 little endian, or UTF-16 big endian, respectively. 3465** SQLite takes the text result from the application from 3466** the 2nd parameter of the sqlite3_result_text* interfaces. 3467** If the 3rd parameter to the sqlite3_result_text* interfaces 3468** is negative, then SQLite takes result text from the 2nd parameter 3469** through the first zero character. 3470** If the 3rd parameter to the sqlite3_result_text* interfaces 3471** is non-negative, then as many bytes (not characters) of the text 3472** pointed to by the 2nd parameter are taken as the application-defined 3473** function result. 3474** If the 4th parameter to the sqlite3_result_text* interfaces 3475** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 3476** function as the destructor on the text or BLOB result when it has 3477** finished using that result. 3478** If the 4th parameter to the sqlite3_result_text* interfaces or 3479** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 3480** assumes that the text or BLOB result is in constant space and does not 3481** copy the it or call a destructor when it has finished using that result. 3482** If the 4th parameter to the sqlite3_result_text* interfaces 3483** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 3484** then SQLite makes a copy of the result into space obtained from 3485** from [sqlite3_malloc()] before it returns. 3486** 3487** The sqlite3_result_value() interface sets the result of 3488** the application-defined function to be a copy the 3489** [unprotected sqlite3_value] object specified by the 2nd parameter. The 3490** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 3491** so that the [sqlite3_value] specified in the parameter may change or 3492** be deallocated after sqlite3_result_value() returns without harm. 3493** A [protected sqlite3_value] object may always be used where an 3494** [unprotected sqlite3_value] object is required, so either 3495** kind of [sqlite3_value] object can be used with this interface. 3496** 3497** If these routines are called from within the different thread 3498** than the one containing the application-defined function that received 3499** the [sqlite3_context] pointer, the results are undefined. 3500** 3501** Requirements: 3502** [H16403] [H16406] [H16409] [H16412] [H16415] [H16418] [H16421] [H16424] 3503** [H16427] [H16430] [H16433] [H16436] [H16439] [H16442] [H16445] [H16448] 3504** [H16451] [H16454] [H16457] [H16460] [H16463] 3505*/ 3506void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 3507void sqlite3_result_double(sqlite3_context*, double); 3508void sqlite3_result_error(sqlite3_context*, const char*, int); 3509void sqlite3_result_error16(sqlite3_context*, const void*, int); 3510void sqlite3_result_error_toobig(sqlite3_context*); 3511void sqlite3_result_error_nomem(sqlite3_context*); 3512void sqlite3_result_error_code(sqlite3_context*, int); 3513void sqlite3_result_int(sqlite3_context*, int); 3514void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 3515void sqlite3_result_null(sqlite3_context*); 3516void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 3517void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 3518void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 3519void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 3520void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 3521void sqlite3_result_zeroblob(sqlite3_context*, int n); 3522 3523/* 3524** CAPI3REF: Define New Collating Sequences {H16600} <S20300> 3525** 3526** These functions are used to add new collation sequences to the 3527** [database connection] specified as the first argument. 3528** 3529** The name of the new collation sequence is specified as a UTF-8 string 3530** for sqlite3_create_collation() and sqlite3_create_collation_v2() 3531** and a UTF-16 string for sqlite3_create_collation16(). In all cases 3532** the name is passed as the second function argument. 3533** 3534** The third argument may be one of the constants [SQLITE_UTF8], 3535** [SQLITE_UTF16LE], or [SQLITE_UTF16BE], indicating that the user-supplied 3536** routine expects to be passed pointers to strings encoded using UTF-8, 3537** UTF-16 little-endian, or UTF-16 big-endian, respectively. The 3538** third argument might also be [SQLITE_UTF16] to indicate that the routine 3539** expects pointers to be UTF-16 strings in the native byte order, or the 3540** argument can be [SQLITE_UTF16_ALIGNED] if the 3541** the routine expects pointers to 16-bit word aligned strings 3542** of UTF-16 in the native byte order. 3543** 3544** A pointer to the user supplied routine must be passed as the fifth 3545** argument. If it is NULL, this is the same as deleting the collation 3546** sequence (so that SQLite cannot call it anymore). 3547** Each time the application supplied function is invoked, it is passed 3548** as its first parameter a copy of the void* passed as the fourth argument 3549** to sqlite3_create_collation() or sqlite3_create_collation16(). 3550** 3551** The remaining arguments to the application-supplied routine are two strings, 3552** each represented by a (length, data) pair and encoded in the encoding 3553** that was passed as the third argument when the collation sequence was 3554** registered. {END} The application defined collation routine should 3555** return negative, zero or positive if the first string is less than, 3556** equal to, or greater than the second string. i.e. (STRING1 - STRING2). 3557** 3558** The sqlite3_create_collation_v2() works like sqlite3_create_collation() 3559** except that it takes an extra argument which is a destructor for 3560** the collation. The destructor is called when the collation is 3561** destroyed and is passed a copy of the fourth parameter void* pointer 3562** of the sqlite3_create_collation_v2(). 3563** Collations are destroyed when they are overridden by later calls to the 3564** collation creation functions or when the [database connection] is closed 3565** using [sqlite3_close()]. 3566** 3567** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 3568** 3569** Requirements: 3570** [H16603] [H16604] [H16606] [H16609] [H16612] [H16615] [H16618] [H16621] 3571** [H16624] [H16627] [H16630] 3572*/ 3573int sqlite3_create_collation( 3574 sqlite3*, 3575 const char *zName, 3576 int eTextRep, 3577 void*, 3578 int(*xCompare)(void*,int,const void*,int,const void*) 3579); 3580int sqlite3_create_collation_v2( 3581 sqlite3*, 3582 const char *zName, 3583 int eTextRep, 3584 void*, 3585 int(*xCompare)(void*,int,const void*,int,const void*), 3586 void(*xDestroy)(void*) 3587); 3588int sqlite3_create_collation16( 3589 sqlite3*, 3590 const void *zName, 3591 int eTextRep, 3592 void*, 3593 int(*xCompare)(void*,int,const void*,int,const void*) 3594); 3595 3596/* 3597** CAPI3REF: Collation Needed Callbacks {H16700} <S20300> 3598** 3599** To avoid having to register all collation sequences before a database 3600** can be used, a single callback function may be registered with the 3601** [database connection] to be called whenever an undefined collation 3602** sequence is required. 3603** 3604** If the function is registered using the sqlite3_collation_needed() API, 3605** then it is passed the names of undefined collation sequences as strings 3606** encoded in UTF-8. {H16703} If sqlite3_collation_needed16() is used, 3607** the names are passed as UTF-16 in machine native byte order. 3608** A call to either function replaces any existing callback. 3609** 3610** When the callback is invoked, the first argument passed is a copy 3611** of the second argument to sqlite3_collation_needed() or 3612** sqlite3_collation_needed16(). The second argument is the database 3613** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 3614** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 3615** sequence function required. The fourth parameter is the name of the 3616** required collation sequence. 3617** 3618** The callback function should register the desired collation using 3619** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 3620** [sqlite3_create_collation_v2()]. 3621** 3622** Requirements: 3623** [H16702] [H16704] [H16706] 3624*/ 3625int sqlite3_collation_needed( 3626 sqlite3*, 3627 void*, 3628 void(*)(void*,sqlite3*,int eTextRep,const char*) 3629); 3630int sqlite3_collation_needed16( 3631 sqlite3*, 3632 void*, 3633 void(*)(void*,sqlite3*,int eTextRep,const void*) 3634); 3635 3636/* 3637** Specify the key for an encrypted database. This routine should be 3638** called right after sqlite3_open(). 3639** 3640** The code to implement this API is not available in the public release 3641** of SQLite. 3642*/ 3643int sqlite3_key( 3644 sqlite3 *db, /* Database to be rekeyed */ 3645 const void *pKey, int nKey /* The key */ 3646); 3647 3648/* 3649** Change the key on an open database. If the current database is not 3650** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 3651** database is decrypted. 3652** 3653** The code to implement this API is not available in the public release 3654** of SQLite. 3655*/ 3656int sqlite3_rekey( 3657 sqlite3 *db, /* Database to be rekeyed */ 3658 const void *pKey, int nKey /* The new key */ 3659); 3660 3661/* 3662** CAPI3REF: Suspend Execution For A Short Time {H10530} <S40410> 3663** 3664** The sqlite3_sleep() function causes the current thread to suspend execution 3665** for at least a number of milliseconds specified in its parameter. 3666** 3667** If the operating system does not support sleep requests with 3668** millisecond time resolution, then the time will be rounded up to 3669** the nearest second. The number of milliseconds of sleep actually 3670** requested from the operating system is returned. 3671** 3672** SQLite implements this interface by calling the xSleep() 3673** method of the default [sqlite3_vfs] object. 3674** 3675** Requirements: [H10533] [H10536] 3676*/ 3677int sqlite3_sleep(int); 3678 3679/* 3680** CAPI3REF: Name Of The Folder Holding Temporary Files {H10310} <S20000> 3681** 3682** If this global variable is made to point to a string which is 3683** the name of a folder (a.k.a. directory), then all temporary files 3684** created by SQLite will be placed in that directory. If this variable 3685** is a NULL pointer, then SQLite performs a search for an appropriate 3686** temporary file directory. 3687** 3688** It is not safe to read or modify this variable in more than one 3689** thread at a time. It is not safe to read or modify this variable 3690** if a [database connection] is being used at the same time in a separate 3691** thread. 3692** It is intended that this variable be set once 3693** as part of process initialization and before any SQLite interface 3694** routines have been called and that this variable remain unchanged 3695** thereafter. 3696** 3697** The [temp_store_directory pragma] may modify this variable and cause 3698** it to point to memory obtained from [sqlite3_malloc]. Furthermore, 3699** the [temp_store_directory pragma] always assumes that any string 3700** that this variable points to is held in memory obtained from 3701** [sqlite3_malloc] and the pragma may attempt to free that memory 3702** using [sqlite3_free]. 3703** Hence, if this variable is modified directly, either it should be 3704** made NULL or made to point to memory obtained from [sqlite3_malloc] 3705** or else the use of the [temp_store_directory pragma] should be avoided. 3706*/ 3707SQLITE_EXTERN char *sqlite3_temp_directory; 3708 3709/* 3710** CAPI3REF: Test For Auto-Commit Mode {H12930} <S60200> 3711** KEYWORDS: {autocommit mode} 3712** 3713** The sqlite3_get_autocommit() interface returns non-zero or 3714** zero if the given database connection is or is not in autocommit mode, 3715** respectively. Autocommit mode is on by default. 3716** Autocommit mode is disabled by a [BEGIN] statement. 3717** Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 3718** 3719** If certain kinds of errors occur on a statement within a multi-statement 3720** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 3721** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 3722** transaction might be rolled back automatically. The only way to 3723** find out whether SQLite automatically rolled back the transaction after 3724** an error is to use this function. 3725** 3726** If another thread changes the autocommit status of the database 3727** connection while this routine is running, then the return value 3728** is undefined. 3729** 3730** Requirements: [H12931] [H12932] [H12933] [H12934] 3731*/ 3732int sqlite3_get_autocommit(sqlite3*); 3733 3734/* 3735** CAPI3REF: Find The Database Handle Of A Prepared Statement {H13120} <S60600> 3736** 3737** The sqlite3_db_handle interface returns the [database connection] handle 3738** to which a [prepared statement] belongs. The [database connection] 3739** returned by sqlite3_db_handle is the same [database connection] that was the first argument 3740** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 3741** create the statement in the first place. 3742** 3743** Requirements: [H13123] 3744*/ 3745sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 3746 3747/* 3748** CAPI3REF: Find the next prepared statement {H13140} <S60600> 3749** 3750** This interface returns a pointer to the next [prepared statement] after 3751** pStmt associated with the [database connection] pDb. If pStmt is NULL 3752** then this interface returns a pointer to the first prepared statement 3753** associated with the database connection pDb. If no prepared statement 3754** satisfies the conditions of this routine, it returns NULL. 3755** 3756** The [database connection] pointer D in a call to 3757** [sqlite3_next_stmt(D,S)] must refer to an open database 3758** connection and in particular must not be a NULL pointer. 3759** 3760** Requirements: [H13143] [H13146] [H13149] [H13152] 3761*/ 3762sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 3763 3764/* 3765** CAPI3REF: Commit And Rollback Notification Callbacks {H12950} <S60400> 3766** 3767** The sqlite3_commit_hook() interface registers a callback 3768** function to be invoked whenever a transaction is [COMMIT | committed]. 3769** Any callback set by a previous call to sqlite3_commit_hook() 3770** for the same database connection is overridden. 3771** The sqlite3_rollback_hook() interface registers a callback 3772** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 3773** Any callback set by a previous call to sqlite3_commit_hook() 3774** for the same database connection is overridden. 3775** The pArg argument is passed through to the callback. 3776** If the callback on a commit hook function returns non-zero, 3777** then the commit is converted into a rollback. 3778** 3779** If another function was previously registered, its 3780** pArg value is returned. Otherwise NULL is returned. 3781** 3782** The callback implementation must not do anything that will modify 3783** the database connection that invoked the callback. Any actions 3784** to modify the database connection must be deferred until after the 3785** completion of the [sqlite3_step()] call that triggered the commit 3786** or rollback hook in the first place. 3787** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3788** database connections for the meaning of "modify" in this paragraph. 3789** 3790** Registering a NULL function disables the callback. 3791** 3792** When the commit hook callback routine returns zero, the [COMMIT] 3793** operation is allowed to continue normally. If the commit hook 3794** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 3795** The rollback hook is invoked on a rollback that results from a commit 3796** hook returning non-zero, just as it would be with any other rollback. 3797** 3798** For the purposes of this API, a transaction is said to have been 3799** rolled back if an explicit "ROLLBACK" statement is executed, or 3800** an error or constraint causes an implicit rollback to occur. 3801** The rollback callback is not invoked if a transaction is 3802** automatically rolled back because the database connection is closed. 3803** The rollback callback is not invoked if a transaction is 3804** rolled back because a commit callback returned non-zero. 3805** <todo> Check on this </todo> 3806** 3807** See also the [sqlite3_update_hook()] interface. 3808** 3809** Requirements: 3810** [H12951] [H12952] [H12953] [H12954] [H12955] 3811** [H12961] [H12962] [H12963] [H12964] 3812*/ 3813void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 3814void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 3815 3816/* 3817** CAPI3REF: Data Change Notification Callbacks {H12970} <S60400> 3818** 3819** The sqlite3_update_hook() interface registers a callback function 3820** with the [database connection] identified by the first argument 3821** to be invoked whenever a row is updated, inserted or deleted. 3822** Any callback set by a previous call to this function 3823** for the same database connection is overridden. 3824** 3825** The second argument is a pointer to the function to invoke when a 3826** row is updated, inserted or deleted. 3827** The first argument to the callback is a copy of the third argument 3828** to sqlite3_update_hook(). 3829** The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 3830** or [SQLITE_UPDATE], depending on the operation that caused the callback 3831** to be invoked. 3832** The third and fourth arguments to the callback contain pointers to the 3833** database and table name containing the affected row. 3834** The final callback parameter is the [rowid] of the row. 3835** In the case of an update, this is the [rowid] after the update takes place. 3836** 3837** The update hook is not invoked when internal system tables are 3838** modified (i.e. sqlite_master and sqlite_sequence). 3839** 3840** In the current implementation, the update hook 3841** is not invoked when duplication rows are deleted because of an 3842** [ON CONFLICT | ON CONFLICT REPLACE] clause. Nor is the update hook 3843** invoked when rows are deleted using the [truncate optimization]. 3844** The exceptions defined in this paragraph might change in a future 3845** release of SQLite. 3846** 3847** The update hook implementation must not do anything that will modify 3848** the database connection that invoked the update hook. Any actions 3849** to modify the database connection must be deferred until after the 3850** completion of the [sqlite3_step()] call that triggered the update hook. 3851** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3852** database connections for the meaning of "modify" in this paragraph. 3853** 3854** If another function was previously registered, its pArg value 3855** is returned. Otherwise NULL is returned. 3856** 3857** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 3858** interfaces. 3859** 3860** Requirements: 3861** [H12971] [H12973] [H12975] [H12977] [H12979] [H12981] [H12983] [H12986] 3862*/ 3863void *sqlite3_update_hook( 3864 sqlite3*, 3865 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 3866 void* 3867); 3868 3869/* 3870** CAPI3REF: Enable Or Disable Shared Pager Cache {H10330} <S30900> 3871** KEYWORDS: {shared cache} {shared cache mode} 3872** 3873** This routine enables or disables the sharing of the database cache 3874** and schema data structures between [database connection | connections] 3875** to the same database. Sharing is enabled if the argument is true 3876** and disabled if the argument is false. 3877** 3878** Cache sharing is enabled and disabled for an entire process. 3879** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 3880** sharing was enabled or disabled for each thread separately. 3881** 3882** The cache sharing mode set by this interface effects all subsequent 3883** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 3884** Existing database connections continue use the sharing mode 3885** that was in effect at the time they were opened. 3886** 3887** Virtual tables cannot be used with a shared cache. When shared 3888** cache is enabled, the [sqlite3_create_module()] API used to register 3889** virtual tables will always return an error. 3890** 3891** This routine returns [SQLITE_OK] if shared cache was enabled or disabled 3892** successfully. An [error code] is returned otherwise. 3893** 3894** Shared cache is disabled by default. But this might change in 3895** future releases of SQLite. Applications that care about shared 3896** cache setting should set it explicitly. 3897** 3898** See Also: [SQLite Shared-Cache Mode] 3899** 3900** Requirements: [H10331] [H10336] [H10337] [H10339] 3901*/ 3902int sqlite3_enable_shared_cache(int); 3903 3904/* 3905** CAPI3REF: Attempt To Free Heap Memory {H17340} <S30220> 3906** 3907** The sqlite3_release_memory() interface attempts to free N bytes 3908** of heap memory by deallocating non-essential memory allocations 3909** held by the database library. {END} Memory used to cache database 3910** pages to improve performance is an example of non-essential memory. 3911** sqlite3_release_memory() returns the number of bytes actually freed, 3912** which might be more or less than the amount requested. 3913** 3914** Requirements: [H17341] [H17342] 3915*/ 3916int sqlite3_release_memory(int); 3917 3918/* 3919** CAPI3REF: Impose A Limit On Heap Size {H17350} <S30220> 3920** 3921** The sqlite3_soft_heap_limit() interface places a "soft" limit 3922** on the amount of heap memory that may be allocated by SQLite. 3923** If an internal allocation is requested that would exceed the 3924** soft heap limit, [sqlite3_release_memory()] is invoked one or 3925** more times to free up some space before the allocation is performed. 3926** 3927** The limit is called "soft", because if [sqlite3_release_memory()] 3928** cannot free sufficient memory to prevent the limit from being exceeded, 3929** the memory is allocated anyway and the current operation proceeds. 3930** 3931** A negative or zero value for N means that there is no soft heap limit and 3932** [sqlite3_release_memory()] will only be called when memory is exhausted. 3933** The default value for the soft heap limit is zero. 3934** 3935** SQLite makes a best effort to honor the soft heap limit. 3936** But if the soft heap limit cannot be honored, execution will 3937** continue without error or notification. This is why the limit is 3938** called a "soft" limit. It is advisory only. 3939** 3940** Prior to SQLite version 3.5.0, this routine only constrained the memory 3941** allocated by a single thread - the same thread in which this routine 3942** runs. Beginning with SQLite version 3.5.0, the soft heap limit is 3943** applied to all threads. The value specified for the soft heap limit 3944** is an upper bound on the total memory allocation for all threads. In 3945** version 3.5.0 there is no mechanism for limiting the heap usage for 3946** individual threads. 3947** 3948** Requirements: 3949** [H16351] [H16352] [H16353] [H16354] [H16355] [H16358] 3950*/ 3951void sqlite3_soft_heap_limit(int); 3952 3953/* 3954** CAPI3REF: Extract Metadata About A Column Of A Table {H12850} <S60300> 3955** 3956** This routine returns metadata about a specific column of a specific 3957** database table accessible using the [database connection] handle 3958** passed as the first function argument. 3959** 3960** The column is identified by the second, third and fourth parameters to 3961** this function. The second parameter is either the name of the database 3962** (i.e. "main", "temp" or an attached database) containing the specified 3963** table or NULL. If it is NULL, then all attached databases are searched 3964** for the table using the same algorithm used by the database engine to 3965** resolve unqualified table references. 3966** 3967** The third and fourth parameters to this function are the table and column 3968** name of the desired column, respectively. Neither of these parameters 3969** may be NULL. 3970** 3971** Metadata is returned by writing to the memory locations passed as the 5th 3972** and subsequent parameters to this function. Any of these arguments may be 3973** NULL, in which case the corresponding element of metadata is omitted. 3974** 3975** <blockquote> 3976** <table border="1"> 3977** <tr><th> Parameter <th> Output<br>Type <th> Description 3978** 3979** <tr><td> 5th <td> const char* <td> Data type 3980** <tr><td> 6th <td> const char* <td> Name of default collation sequence 3981** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 3982** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 3983** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 3984** </table> 3985** </blockquote> 3986** 3987** The memory pointed to by the character pointers returned for the 3988** declaration type and collation sequence is valid only until the next 3989** call to any SQLite API function. 3990** 3991** If the specified table is actually a view, an [error code] is returned. 3992** 3993** If the specified column is "rowid", "oid" or "_rowid_" and an 3994** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 3995** parameters are set for the explicitly declared column. If there is no 3996** explicitly declared [INTEGER PRIMARY KEY] column, then the output 3997** parameters are set as follows: 3998** 3999** <pre> 4000** data type: "INTEGER" 4001** collation sequence: "BINARY" 4002** not null: 0 4003** primary key: 1 4004** auto increment: 0 4005** </pre> 4006** 4007** This function may load one or more schemas from database files. If an 4008** error occurs during this process, or if the requested table or column 4009** cannot be found, an [error code] is returned and an error message left 4010** in the [database connection] (to be retrieved using sqlite3_errmsg()). 4011** 4012** This API is only available if the library was compiled with the 4013** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4014*/ 4015int sqlite3_table_column_metadata( 4016 sqlite3 *db, /* Connection handle */ 4017 const char *zDbName, /* Database name or NULL */ 4018 const char *zTableName, /* Table name */ 4019 const char *zColumnName, /* Column name */ 4020 char const **pzDataType, /* OUTPUT: Declared data type */ 4021 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4022 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4023 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4024 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4025); 4026 4027/* 4028** CAPI3REF: Load An Extension {H12600} <S20500> 4029** 4030** This interface loads an SQLite extension library from the named file. 4031** 4032** {H12601} The sqlite3_load_extension() interface attempts to load an 4033** SQLite extension library contained in the file zFile. 4034** 4035** {H12602} The entry point is zProc. 4036** 4037** {H12603} zProc may be 0, in which case the name of the entry point 4038** defaults to "sqlite3_extension_init". 4039** 4040** {H12604} The sqlite3_load_extension() interface shall return 4041** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4042** 4043** {H12605} If an error occurs and pzErrMsg is not 0, then the 4044** [sqlite3_load_extension()] interface shall attempt to 4045** fill *pzErrMsg with error message text stored in memory 4046** obtained from [sqlite3_malloc()]. {END} The calling function 4047** should free this memory by calling [sqlite3_free()]. 4048** 4049** {H12606} Extension loading must be enabled using 4050** [sqlite3_enable_load_extension()] prior to calling this API, 4051** otherwise an error will be returned. 4052*/ 4053int sqlite3_load_extension( 4054 sqlite3 *db, /* Load the extension into this database connection */ 4055 const char *zFile, /* Name of the shared library containing extension */ 4056 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4057 char **pzErrMsg /* Put error message here if not 0 */ 4058); 4059 4060/* 4061** CAPI3REF: Enable Or Disable Extension Loading {H12620} <S20500> 4062** 4063** So as not to open security holes in older applications that are 4064** unprepared to deal with extension loading, and as a means of disabling 4065** extension loading while evaluating user-entered SQL, the following API 4066** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4067** 4068** Extension loading is off by default. See ticket #1863. 4069** 4070** {H12621} Call the sqlite3_enable_load_extension() routine with onoff==1 4071** to turn extension loading on and call it with onoff==0 to turn 4072** it back off again. 4073** 4074** {H12622} Extension loading is off by default. 4075*/ 4076int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4077 4078/* 4079** CAPI3REF: Automatically Load An Extensions {H12640} <S20500> 4080** 4081** This API can be invoked at program startup in order to register 4082** one or more statically linked extensions that will be available 4083** to all new [database connections]. {END} 4084** 4085** This routine stores a pointer to the extension in an array that is 4086** obtained from [sqlite3_malloc()]. If you run a memory leak checker 4087** on your program and it reports a leak because of this array, invoke 4088** [sqlite3_reset_auto_extension()] prior to shutdown to free the memory. 4089** 4090** {H12641} This function registers an extension entry point that is 4091** automatically invoked whenever a new [database connection] 4092** is opened using [sqlite3_open()], [sqlite3_open16()], 4093** or [sqlite3_open_v2()]. 4094** 4095** {H12642} Duplicate extensions are detected so calling this routine 4096** multiple times with the same extension is harmless. 4097** 4098** {H12643} This routine stores a pointer to the extension in an array 4099** that is obtained from [sqlite3_malloc()]. 4100** 4101** {H12644} Automatic extensions apply across all threads. 4102*/ 4103int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4104 4105/* 4106** CAPI3REF: Reset Automatic Extension Loading {H12660} <S20500> 4107** 4108** This function disables all previously registered automatic 4109** extensions. {END} It undoes the effect of all prior 4110** [sqlite3_auto_extension()] calls. 4111** 4112** {H12661} This function disables all previously registered 4113** automatic extensions. 4114** 4115** {H12662} This function disables automatic extensions in all threads. 4116*/ 4117void sqlite3_reset_auto_extension(void); 4118 4119/* 4120****** EXPERIMENTAL - subject to change without notice ************** 4121** 4122** The interface to the virtual-table mechanism is currently considered 4123** to be experimental. The interface might change in incompatible ways. 4124** If this is a problem for you, do not use the interface at this time. 4125** 4126** When the virtual-table mechanism stabilizes, we will declare the 4127** interface fixed, support it indefinitely, and remove this comment. 4128*/ 4129 4130/* 4131** Structures used by the virtual table interface 4132*/ 4133typedef struct sqlite3_vtab sqlite3_vtab; 4134typedef struct sqlite3_index_info sqlite3_index_info; 4135typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4136typedef struct sqlite3_module sqlite3_module; 4137 4138/* 4139** CAPI3REF: Virtual Table Object {H18000} <S20400> 4140** KEYWORDS: sqlite3_module {virtual table module} 4141** EXPERIMENTAL 4142** 4143** This structure, sometimes called a a "virtual table module", 4144** defines the implementation of a [virtual tables]. 4145** This structure consists mostly of methods for the module. 4146** 4147** A virtual table module is created by filling in a persistent 4148** instance of this structure and passing a pointer to that instance 4149** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4150** The registration remains valid until it is replaced by a different 4151** module or until the [database connection] closes. The content 4152** of this structure must not change while it is registered with 4153** any database connection. 4154*/ 4155struct sqlite3_module { 4156 int iVersion; 4157 int (*xCreate)(sqlite3*, void *pAux, 4158 int argc, const char *const*argv, 4159 sqlite3_vtab **ppVTab, char**); 4160 int (*xConnect)(sqlite3*, void *pAux, 4161 int argc, const char *const*argv, 4162 sqlite3_vtab **ppVTab, char**); 4163 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4164 int (*xDisconnect)(sqlite3_vtab *pVTab); 4165 int (*xDestroy)(sqlite3_vtab *pVTab); 4166 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4167 int (*xClose)(sqlite3_vtab_cursor*); 4168 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4169 int argc, sqlite3_value **argv); 4170 int (*xNext)(sqlite3_vtab_cursor*); 4171 int (*xEof)(sqlite3_vtab_cursor*); 4172 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4173 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4174 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4175 int (*xBegin)(sqlite3_vtab *pVTab); 4176 int (*xSync)(sqlite3_vtab *pVTab); 4177 int (*xCommit)(sqlite3_vtab *pVTab); 4178 int (*xRollback)(sqlite3_vtab *pVTab); 4179 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4180 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4181 void **ppArg); 4182 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4183}; 4184 4185/* 4186** CAPI3REF: Virtual Table Indexing Information {H18100} <S20400> 4187** KEYWORDS: sqlite3_index_info 4188** EXPERIMENTAL 4189** 4190** The sqlite3_index_info structure and its substructures is used to 4191** pass information into and receive the reply from the [xBestIndex] 4192** method of a [virtual table module]. The fields under **Inputs** are the 4193** inputs to xBestIndex and are read-only. xBestIndex inserts its 4194** results into the **Outputs** fields. 4195** 4196** The aConstraint[] array records WHERE clause constraints of the form: 4197** 4198** <pre>column OP expr</pre> 4199** 4200** where OP is =, <, <=, >, or >=. The particular operator is 4201** stored in aConstraint[].op. The index of the column is stored in 4202** aConstraint[].iColumn. aConstraint[].usable is TRUE if the 4203** expr on the right-hand side can be evaluated (and thus the constraint 4204** is usable) and false if it cannot. 4205** 4206** The optimizer automatically inverts terms of the form "expr OP column" 4207** and makes other simplifications to the WHERE clause in an attempt to 4208** get as many WHERE clause terms into the form shown above as possible. 4209** The aConstraint[] array only reports WHERE clause terms in the correct 4210** form that refer to the particular virtual table being queried. 4211** 4212** Information about the ORDER BY clause is stored in aOrderBy[]. 4213** Each term of aOrderBy records a column of the ORDER BY clause. 4214** 4215** The [xBestIndex] method must fill aConstraintUsage[] with information 4216** about what parameters to pass to xFilter. If argvIndex>0 then 4217** the right-hand side of the corresponding aConstraint[] is evaluated 4218** and becomes the argvIndex-th entry in argv. If aConstraintUsage[].omit 4219** is true, then the constraint is assumed to be fully handled by the 4220** virtual table and is not checked again by SQLite. 4221** 4222** The idxNum and idxPtr values are recorded and passed into the 4223** [xFilter] method. 4224** [sqlite3_free()] is used to free idxPtr if and only iff 4225** needToFreeIdxPtr is true. 4226** 4227** The orderByConsumed means that output from [xFilter]/[xNext] will occur in 4228** the correct order to satisfy the ORDER BY clause so that no separate 4229** sorting step is required. 4230** 4231** The estimatedCost value is an estimate of the cost of doing the 4232** particular lookup. A full scan of a table with N entries should have 4233** a cost of N. A binary search of a table of N entries should have a 4234** cost of approximately log(N). 4235*/ 4236struct sqlite3_index_info { 4237 /* Inputs */ 4238 int nConstraint; /* Number of entries in aConstraint */ 4239 struct sqlite3_index_constraint { 4240 int iColumn; /* Column on left-hand side of constraint */ 4241 unsigned char op; /* Constraint operator */ 4242 unsigned char usable; /* True if this constraint is usable */ 4243 int iTermOffset; /* Used internally - xBestIndex should ignore */ 4244 } *aConstraint; /* Table of WHERE clause constraints */ 4245 int nOrderBy; /* Number of terms in the ORDER BY clause */ 4246 struct sqlite3_index_orderby { 4247 int iColumn; /* Column number */ 4248 unsigned char desc; /* True for DESC. False for ASC. */ 4249 } *aOrderBy; /* The ORDER BY clause */ 4250 /* Outputs */ 4251 struct sqlite3_index_constraint_usage { 4252 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 4253 unsigned char omit; /* Do not code a test for this constraint */ 4254 } *aConstraintUsage; 4255 int idxNum; /* Number used to identify the index */ 4256 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 4257 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 4258 int orderByConsumed; /* True if output is already ordered */ 4259 double estimatedCost; /* Estimated cost of using this index */ 4260}; 4261#define SQLITE_INDEX_CONSTRAINT_EQ 2 4262#define SQLITE_INDEX_CONSTRAINT_GT 4 4263#define SQLITE_INDEX_CONSTRAINT_LE 8 4264#define SQLITE_INDEX_CONSTRAINT_LT 16 4265#define SQLITE_INDEX_CONSTRAINT_GE 32 4266#define SQLITE_INDEX_CONSTRAINT_MATCH 64 4267 4268/* 4269** CAPI3REF: Register A Virtual Table Implementation {H18200} <S20400> 4270** EXPERIMENTAL 4271** 4272** This routine is used to register a new [virtual table module] name. 4273** Module names must be registered before 4274** creating a new [virtual table] using the module, or before using a 4275** preexisting [virtual table] for the module. 4276** 4277** The module name is registered on the [database connection] specified 4278** by the first parameter. The name of the module is given by the 4279** second parameter. The third parameter is a pointer to 4280** the implementation of the [virtual table module]. The fourth 4281** parameter is an arbitrary client data pointer that is passed through 4282** into the [xCreate] and [xConnect] methods of the virtual table module 4283** when a new virtual table is be being created or reinitialized. 4284** 4285** This interface has exactly the same effect as calling 4286** [sqlite3_create_module_v2()] with a NULL client data destructor. 4287*/ 4288SQLITE_EXPERIMENTAL int sqlite3_create_module( 4289 sqlite3 *db, /* SQLite connection to register module with */ 4290 const char *zName, /* Name of the module */ 4291 const sqlite3_module *p, /* Methods for the module */ 4292 void *pClientData /* Client data for xCreate/xConnect */ 4293); 4294 4295/* 4296** CAPI3REF: Register A Virtual Table Implementation {H18210} <S20400> 4297** EXPERIMENTAL 4298** 4299** This routine is identical to the [sqlite3_create_module()] method, 4300** except that it has an extra parameter to specify 4301** a destructor function for the client data pointer. SQLite will 4302** invoke the destructor function (if it is not NULL) when SQLite 4303** no longer needs the pClientData pointer. 4304*/ 4305SQLITE_EXPERIMENTAL int sqlite3_create_module_v2( 4306 sqlite3 *db, /* SQLite connection to register module with */ 4307 const char *zName, /* Name of the module */ 4308 const sqlite3_module *p, /* Methods for the module */ 4309 void *pClientData, /* Client data for xCreate/xConnect */ 4310 void(*xDestroy)(void*) /* Module destructor function */ 4311); 4312 4313/* 4314** CAPI3REF: Virtual Table Instance Object {H18010} <S20400> 4315** KEYWORDS: sqlite3_vtab 4316** EXPERIMENTAL 4317** 4318** Every [virtual table module] implementation uses a subclass 4319** of the following structure to describe a particular instance 4320** of the [virtual table]. Each subclass will 4321** be tailored to the specific needs of the module implementation. 4322** The purpose of this superclass is to define certain fields that are 4323** common to all module implementations. 4324** 4325** Virtual tables methods can set an error message by assigning a 4326** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 4327** take care that any prior string is freed by a call to [sqlite3_free()] 4328** prior to assigning a new string to zErrMsg. After the error message 4329** is delivered up to the client application, the string will be automatically 4330** freed by sqlite3_free() and the zErrMsg field will be zeroed. 4331*/ 4332struct sqlite3_vtab { 4333 const sqlite3_module *pModule; /* The module for this virtual table */ 4334 int nRef; /* Used internally */ 4335 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 4336 /* Virtual table implementations will typically add additional fields */ 4337}; 4338 4339/* 4340** CAPI3REF: Virtual Table Cursor Object {H18020} <S20400> 4341** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 4342** EXPERIMENTAL 4343** 4344** Every [virtual table module] implementation uses a subclass of the 4345** following structure to describe cursors that point into the 4346** [virtual table] and are used 4347** to loop through the virtual table. Cursors are created using the 4348** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 4349** by the [sqlite3_module.xClose | xClose] method. Cussors are used 4350** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 4351** of the module. Each module implementation will define 4352** the content of a cursor structure to suit its own needs. 4353** 4354** This superclass exists in order to define fields of the cursor that 4355** are common to all implementations. 4356*/ 4357struct sqlite3_vtab_cursor { 4358 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 4359 /* Virtual table implementations will typically add additional fields */ 4360}; 4361 4362/* 4363** CAPI3REF: Declare The Schema Of A Virtual Table {H18280} <S20400> 4364** EXPERIMENTAL 4365** 4366** The [xCreate] and [xConnect] methods of a 4367** [virtual table module] call this interface 4368** to declare the format (the names and datatypes of the columns) of 4369** the virtual tables they implement. 4370*/ 4371SQLITE_EXPERIMENTAL int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 4372 4373/* 4374** CAPI3REF: Overload A Function For A Virtual Table {H18300} <S20400> 4375** EXPERIMENTAL 4376** 4377** Virtual tables can provide alternative implementations of functions 4378** using the [xFindFunction] method of the [virtual table module]. 4379** But global versions of those functions 4380** must exist in order to be overloaded. 4381** 4382** This API makes sure a global version of a function with a particular 4383** name and number of parameters exists. If no such function exists 4384** before this API is called, a new function is created. The implementation 4385** of the new function always causes an exception to be thrown. So 4386** the new function is not good for anything by itself. Its only 4387** purpose is to be a placeholder function that can be overloaded 4388** by a [virtual table]. 4389*/ 4390SQLITE_EXPERIMENTAL int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 4391 4392/* 4393** The interface to the virtual-table mechanism defined above (back up 4394** to a comment remarkably similar to this one) is currently considered 4395** to be experimental. The interface might change in incompatible ways. 4396** If this is a problem for you, do not use the interface at this time. 4397** 4398** When the virtual-table mechanism stabilizes, we will declare the 4399** interface fixed, support it indefinitely, and remove this comment. 4400** 4401****** EXPERIMENTAL - subject to change without notice ************** 4402*/ 4403 4404/* 4405** CAPI3REF: A Handle To An Open BLOB {H17800} <S30230> 4406** KEYWORDS: {BLOB handle} {BLOB handles} 4407** 4408** An instance of this object represents an open BLOB on which 4409** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 4410** Objects of this type are created by [sqlite3_blob_open()] 4411** and destroyed by [sqlite3_blob_close()]. 4412** The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 4413** can be used to read or write small subsections of the BLOB. 4414** The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 4415*/ 4416typedef struct sqlite3_blob sqlite3_blob; 4417 4418/* 4419** CAPI3REF: Open A BLOB For Incremental I/O {H17810} <S30230> 4420** 4421** This interfaces opens a [BLOB handle | handle] to the BLOB located 4422** in row iRow, column zColumn, table zTable in database zDb; 4423** in other words, the same BLOB that would be selected by: 4424** 4425** <pre> 4426** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 4427** </pre> {END} 4428** 4429** If the flags parameter is non-zero, then the BLOB is opened for read 4430** and write access. If it is zero, the BLOB is opened for read access. 4431** 4432** Note that the database name is not the filename that contains 4433** the database but rather the symbolic name of the database that 4434** is assigned when the database is connected using [ATTACH]. 4435** For the main database file, the database name is "main". 4436** For TEMP tables, the database name is "temp". 4437** 4438** On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 4439** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 4440** to be a null pointer. 4441** This function sets the [database connection] error code and message 4442** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 4443** functions. Note that the *ppBlob variable is always initialized in a 4444** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 4445** regardless of the success or failure of this routine. 4446** 4447** If the row that a BLOB handle points to is modified by an 4448** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 4449** then the BLOB handle is marked as "expired". 4450** This is true if any column of the row is changed, even a column 4451** other than the one the BLOB handle is open on. 4452** Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 4453** a expired BLOB handle fail with an return code of [SQLITE_ABORT]. 4454** Changes written into a BLOB prior to the BLOB expiring are not 4455** rollback by the expiration of the BLOB. Such changes will eventually 4456** commit if the transaction continues to completion. 4457** 4458** Use the [sqlite3_blob_bytes()] interface to determine the size of 4459** the opened blob. The size of a blob may not be changed by this 4460** underface. Use the [UPDATE] SQL command to change the size of a 4461** blob. 4462** 4463** The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 4464** and the built-in [zeroblob] SQL function can be used, if desired, 4465** to create an empty, zero-filled blob in which to read or write using 4466** this interface. 4467** 4468** To avoid a resource leak, every open [BLOB handle] should eventually 4469** be released by a call to [sqlite3_blob_close()]. 4470** 4471** Requirements: 4472** [H17813] [H17814] [H17816] [H17819] [H17821] [H17824] 4473*/ 4474int sqlite3_blob_open( 4475 sqlite3*, 4476 const char *zDb, 4477 const char *zTable, 4478 const char *zColumn, 4479 sqlite3_int64 iRow, 4480 int flags, 4481 sqlite3_blob **ppBlob 4482); 4483 4484/* 4485** CAPI3REF: Close A BLOB Handle {H17830} <S30230> 4486** 4487** Closes an open [BLOB handle]. 4488** 4489** Closing a BLOB shall cause the current transaction to commit 4490** if there are no other BLOBs, no pending prepared statements, and the 4491** database connection is in [autocommit mode]. 4492** If any writes were made to the BLOB, they might be held in cache 4493** until the close operation if they will fit. 4494** 4495** Closing the BLOB often forces the changes 4496** out to disk and so if any I/O errors occur, they will likely occur 4497** at the time when the BLOB is closed. Any errors that occur during 4498** closing are reported as a non-zero return value. 4499** 4500** The BLOB is closed unconditionally. Even if this routine returns 4501** an error code, the BLOB is still closed. 4502** 4503** Calling this routine with a null pointer (which as would be returned 4504** by failed call to [sqlite3_blob_open()]) is a harmless no-op. 4505** 4506** Requirements: 4507** [H17833] [H17836] [H17839] 4508*/ 4509int sqlite3_blob_close(sqlite3_blob *); 4510 4511/* 4512** CAPI3REF: Return The Size Of An Open BLOB {H17840} <S30230> 4513** 4514** Returns the size in bytes of the BLOB accessible via the 4515** successfully opened [BLOB handle] in its only argument. The 4516** incremental blob I/O routines can only read or overwriting existing 4517** blob content; they cannot change the size of a blob. 4518** 4519** This routine only works on a [BLOB handle] which has been created 4520** by a prior successful call to [sqlite3_blob_open()] and which has not 4521** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4522** to this routine results in undefined and probably undesirable behavior. 4523** 4524** Requirements: 4525** [H17843] 4526*/ 4527int sqlite3_blob_bytes(sqlite3_blob *); 4528 4529/* 4530** CAPI3REF: Read Data From A BLOB Incrementally {H17850} <S30230> 4531** 4532** This function is used to read data from an open [BLOB handle] into a 4533** caller-supplied buffer. N bytes of data are copied into buffer Z 4534** from the open BLOB, starting at offset iOffset. 4535** 4536** If offset iOffset is less than N bytes from the end of the BLOB, 4537** [SQLITE_ERROR] is returned and no data is read. If N or iOffset is 4538** less than zero, [SQLITE_ERROR] is returned and no data is read. 4539** The size of the blob (and hence the maximum value of N+iOffset) 4540** can be determined using the [sqlite3_blob_bytes()] interface. 4541** 4542** An attempt to read from an expired [BLOB handle] fails with an 4543** error code of [SQLITE_ABORT]. 4544** 4545** On success, SQLITE_OK is returned. 4546** Otherwise, an [error code] or an [extended error code] is returned. 4547** 4548** This routine only works on a [BLOB handle] which has been created 4549** by a prior successful call to [sqlite3_blob_open()] and which has not 4550** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4551** to this routine results in undefined and probably undesirable behavior. 4552** 4553** See also: [sqlite3_blob_write()]. 4554** 4555** Requirements: 4556** [H17853] [H17856] [H17859] [H17862] [H17863] [H17865] [H17868] 4557*/ 4558int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 4559 4560/* 4561** CAPI3REF: Write Data Into A BLOB Incrementally {H17870} <S30230> 4562** 4563** This function is used to write data into an open [BLOB handle] from a 4564** caller-supplied buffer. N bytes of data are copied from the buffer Z 4565** into the open BLOB, starting at offset iOffset. 4566** 4567** If the [BLOB handle] passed as the first argument was not opened for 4568** writing (the flags parameter to [sqlite3_blob_open()] was zero), 4569** this function returns [SQLITE_READONLY]. 4570** 4571** This function may only modify the contents of the BLOB; it is 4572** not possible to increase the size of a BLOB using this API. 4573** If offset iOffset is less than N bytes from the end of the BLOB, 4574** [SQLITE_ERROR] is returned and no data is written. If N is 4575** less than zero [SQLITE_ERROR] is returned and no data is written. 4576** The size of the BLOB (and hence the maximum value of N+iOffset) 4577** can be determined using the [sqlite3_blob_bytes()] interface. 4578** 4579** An attempt to write to an expired [BLOB handle] fails with an 4580** error code of [SQLITE_ABORT]. Writes to the BLOB that occurred 4581** before the [BLOB handle] expired are not rolled back by the 4582** expiration of the handle, though of course those changes might 4583** have been overwritten by the statement that expired the BLOB handle 4584** or by other independent statements. 4585** 4586** On success, SQLITE_OK is returned. 4587** Otherwise, an [error code] or an [extended error code] is returned. 4588** 4589** This routine only works on a [BLOB handle] which has been created 4590** by a prior successful call to [sqlite3_blob_open()] and which has not 4591** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4592** to this routine results in undefined and probably undesirable behavior. 4593** 4594** See also: [sqlite3_blob_read()]. 4595** 4596** Requirements: 4597** [H17873] [H17874] [H17875] [H17876] [H17877] [H17879] [H17882] [H17885] 4598** [H17888] 4599*/ 4600int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 4601 4602/* 4603** CAPI3REF: Virtual File System Objects {H11200} <S20100> 4604** 4605** A virtual filesystem (VFS) is an [sqlite3_vfs] object 4606** that SQLite uses to interact 4607** with the underlying operating system. Most SQLite builds come with a 4608** single default VFS that is appropriate for the host computer. 4609** New VFSes can be registered and existing VFSes can be unregistered. 4610** The following interfaces are provided. 4611** 4612** The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 4613** Names are case sensitive. 4614** Names are zero-terminated UTF-8 strings. 4615** If there is no match, a NULL pointer is returned. 4616** If zVfsName is NULL then the default VFS is returned. 4617** 4618** New VFSes are registered with sqlite3_vfs_register(). 4619** Each new VFS becomes the default VFS if the makeDflt flag is set. 4620** The same VFS can be registered multiple times without injury. 4621** To make an existing VFS into the default VFS, register it again 4622** with the makeDflt flag set. If two different VFSes with the 4623** same name are registered, the behavior is undefined. If a 4624** VFS is registered with a name that is NULL or an empty string, 4625** then the behavior is undefined. 4626** 4627** Unregister a VFS with the sqlite3_vfs_unregister() interface. 4628** If the default VFS is unregistered, another VFS is chosen as 4629** the default. The choice for the new VFS is arbitrary. 4630** 4631** Requirements: 4632** [H11203] [H11206] [H11209] [H11212] [H11215] [H11218] 4633*/ 4634sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 4635int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 4636int sqlite3_vfs_unregister(sqlite3_vfs*); 4637 4638/* 4639** CAPI3REF: Mutexes {H17000} <S20000> 4640** 4641** The SQLite core uses these routines for thread 4642** synchronization. Though they are intended for internal 4643** use by SQLite, code that links against SQLite is 4644** permitted to use any of these routines. 4645** 4646** The SQLite source code contains multiple implementations 4647** of these mutex routines. An appropriate implementation 4648** is selected automatically at compile-time. The following 4649** implementations are available in the SQLite core: 4650** 4651** <ul> 4652** <li> SQLITE_MUTEX_OS2 4653** <li> SQLITE_MUTEX_PTHREAD 4654** <li> SQLITE_MUTEX_W32 4655** <li> SQLITE_MUTEX_NOOP 4656** </ul> 4657** 4658** The SQLITE_MUTEX_NOOP implementation is a set of routines 4659** that does no real locking and is appropriate for use in 4660** a single-threaded application. The SQLITE_MUTEX_OS2, 4661** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations 4662** are appropriate for use on OS/2, Unix, and Windows. 4663** 4664** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 4665** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 4666** implementation is included with the library. In this case the 4667** application must supply a custom mutex implementation using the 4668** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 4669** before calling sqlite3_initialize() or any other public sqlite3_ 4670** function that calls sqlite3_initialize(). 4671** 4672** {H17011} The sqlite3_mutex_alloc() routine allocates a new 4673** mutex and returns a pointer to it. {H17012} If it returns NULL 4674** that means that a mutex could not be allocated. {H17013} SQLite 4675** will unwind its stack and return an error. {H17014} The argument 4676** to sqlite3_mutex_alloc() is one of these integer constants: 4677** 4678** <ul> 4679** <li> SQLITE_MUTEX_FAST 4680** <li> SQLITE_MUTEX_RECURSIVE 4681** <li> SQLITE_MUTEX_STATIC_MASTER 4682** <li> SQLITE_MUTEX_STATIC_MEM 4683** <li> SQLITE_MUTEX_STATIC_MEM2 4684** <li> SQLITE_MUTEX_STATIC_PRNG 4685** <li> SQLITE_MUTEX_STATIC_LRU 4686** <li> SQLITE_MUTEX_STATIC_LRU2 4687** </ul> 4688** 4689** {H17015} The first two constants cause sqlite3_mutex_alloc() to create 4690** a new mutex. The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 4691** is used but not necessarily so when SQLITE_MUTEX_FAST is used. {END} 4692** The mutex implementation does not need to make a distinction 4693** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 4694** not want to. {H17016} But SQLite will only request a recursive mutex in 4695** cases where it really needs one. {END} If a faster non-recursive mutex 4696** implementation is available on the host platform, the mutex subsystem 4697** might return such a mutex in response to SQLITE_MUTEX_FAST. 4698** 4699** {H17017} The other allowed parameters to sqlite3_mutex_alloc() each return 4700** a pointer to a static preexisting mutex. {END} Four static mutexes are 4701** used by the current version of SQLite. Future versions of SQLite 4702** may add additional static mutexes. Static mutexes are for internal 4703** use by SQLite only. Applications that use SQLite mutexes should 4704** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 4705** SQLITE_MUTEX_RECURSIVE. 4706** 4707** {H17018} Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 4708** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 4709** returns a different mutex on every call. {H17034} But for the static 4710** mutex types, the same mutex is returned on every call that has 4711** the same type number. 4712** 4713** {H17019} The sqlite3_mutex_free() routine deallocates a previously 4714** allocated dynamic mutex. {H17020} SQLite is careful to deallocate every 4715** dynamic mutex that it allocates. {A17021} The dynamic mutexes must not be in 4716** use when they are deallocated. {A17022} Attempting to deallocate a static 4717** mutex results in undefined behavior. {H17023} SQLite never deallocates 4718** a static mutex. {END} 4719** 4720** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 4721** to enter a mutex. {H17024} If another thread is already within the mutex, 4722** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 4723** SQLITE_BUSY. {H17025} The sqlite3_mutex_try() interface returns [SQLITE_OK] 4724** upon successful entry. {H17026} Mutexes created using 4725** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 4726** {H17027} In such cases the, 4727** mutex must be exited an equal number of times before another thread 4728** can enter. {A17028} If the same thread tries to enter any other 4729** kind of mutex more than once, the behavior is undefined. 4730** {H17029} SQLite will never exhibit 4731** such behavior in its own use of mutexes. 4732** 4733** Some systems (for example, Windows 95) do not support the operation 4734** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 4735** will always return SQLITE_BUSY. {H17030} The SQLite core only ever uses 4736** sqlite3_mutex_try() as an optimization so this is acceptable behavior. 4737** 4738** {H17031} The sqlite3_mutex_leave() routine exits a mutex that was 4739** previously entered by the same thread. {A17032} The behavior 4740** is undefined if the mutex is not currently entered by the 4741** calling thread or is not currently allocated. {H17033} SQLite will 4742** never do either. {END} 4743** 4744** If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 4745** sqlite3_mutex_leave() is a NULL pointer, then all three routines 4746** behave as no-ops. 4747** 4748** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 4749*/ 4750sqlite3_mutex *sqlite3_mutex_alloc(int); 4751void sqlite3_mutex_free(sqlite3_mutex*); 4752void sqlite3_mutex_enter(sqlite3_mutex*); 4753int sqlite3_mutex_try(sqlite3_mutex*); 4754void sqlite3_mutex_leave(sqlite3_mutex*); 4755 4756/* 4757** CAPI3REF: Mutex Methods Object {H17120} <S20130> 4758** EXPERIMENTAL 4759** 4760** An instance of this structure defines the low-level routines 4761** used to allocate and use mutexes. 4762** 4763** Usually, the default mutex implementations provided by SQLite are 4764** sufficient, however the user has the option of substituting a custom 4765** implementation for specialized deployments or systems for which SQLite 4766** does not provide a suitable implementation. In this case, the user 4767** creates and populates an instance of this structure to pass 4768** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 4769** Additionally, an instance of this structure can be used as an 4770** output variable when querying the system for the current mutex 4771** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 4772** 4773** The xMutexInit method defined by this structure is invoked as 4774** part of system initialization by the sqlite3_initialize() function. 4775** {H17001} The xMutexInit routine shall be called by SQLite once for each 4776** effective call to [sqlite3_initialize()]. 4777** 4778** The xMutexEnd method defined by this structure is invoked as 4779** part of system shutdown by the sqlite3_shutdown() function. The 4780** implementation of this method is expected to release all outstanding 4781** resources obtained by the mutex methods implementation, especially 4782** those obtained by the xMutexInit method. {H17003} The xMutexEnd() 4783** interface shall be invoked once for each call to [sqlite3_shutdown()]. 4784** 4785** The remaining seven methods defined by this structure (xMutexAlloc, 4786** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 4787** xMutexNotheld) implement the following interfaces (respectively): 4788** 4789** <ul> 4790** <li> [sqlite3_mutex_alloc()] </li> 4791** <li> [sqlite3_mutex_free()] </li> 4792** <li> [sqlite3_mutex_enter()] </li> 4793** <li> [sqlite3_mutex_try()] </li> 4794** <li> [sqlite3_mutex_leave()] </li> 4795** <li> [sqlite3_mutex_held()] </li> 4796** <li> [sqlite3_mutex_notheld()] </li> 4797** </ul> 4798** 4799** The only difference is that the public sqlite3_XXX functions enumerated 4800** above silently ignore any invocations that pass a NULL pointer instead 4801** of a valid mutex handle. The implementations of the methods defined 4802** by this structure are not required to handle this case, the results 4803** of passing a NULL pointer instead of a valid mutex handle are undefined 4804** (i.e. it is acceptable to provide an implementation that segfaults if 4805** it is passed a NULL pointer). 4806*/ 4807typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 4808struct sqlite3_mutex_methods { 4809 int (*xMutexInit)(void); 4810 int (*xMutexEnd)(void); 4811 sqlite3_mutex *(*xMutexAlloc)(int); 4812 void (*xMutexFree)(sqlite3_mutex *); 4813 void (*xMutexEnter)(sqlite3_mutex *); 4814 int (*xMutexTry)(sqlite3_mutex *); 4815 void (*xMutexLeave)(sqlite3_mutex *); 4816 int (*xMutexHeld)(sqlite3_mutex *); 4817 int (*xMutexNotheld)(sqlite3_mutex *); 4818}; 4819 4820/* 4821** CAPI3REF: Mutex Verification Routines {H17080} <S20130> <S30800> 4822** 4823** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 4824** are intended for use inside assert() statements. {H17081} The SQLite core 4825** never uses these routines except inside an assert() and applications 4826** are advised to follow the lead of the core. {H17082} The core only 4827** provides implementations for these routines when it is compiled 4828** with the SQLITE_DEBUG flag. {A17087} External mutex implementations 4829** are only required to provide these routines if SQLITE_DEBUG is 4830** defined and if NDEBUG is not defined. 4831** 4832** {H17083} These routines should return true if the mutex in their argument 4833** is held or not held, respectively, by the calling thread. 4834** 4835** {X17084} The implementation is not required to provided versions of these 4836** routines that actually work. If the implementation does not provide working 4837** versions of these routines, it should at least provide stubs that always 4838** return true so that one does not get spurious assertion failures. 4839** 4840** {H17085} If the argument to sqlite3_mutex_held() is a NULL pointer then 4841** the routine should return 1. {END} This seems counter-intuitive since 4842** clearly the mutex cannot be held if it does not exist. But the 4843** the reason the mutex does not exist is because the build is not 4844** using mutexes. And we do not want the assert() containing the 4845** call to sqlite3_mutex_held() to fail, so a non-zero return is 4846** the appropriate thing to do. {H17086} The sqlite3_mutex_notheld() 4847** interface should also return 1 when given a NULL pointer. 4848*/ 4849int sqlite3_mutex_held(sqlite3_mutex*); 4850int sqlite3_mutex_notheld(sqlite3_mutex*); 4851 4852/* 4853** CAPI3REF: Mutex Types {H17001} <H17000> 4854** 4855** The [sqlite3_mutex_alloc()] interface takes a single argument 4856** which is one of these integer constants. 4857** 4858** The set of static mutexes may change from one SQLite release to the 4859** next. Applications that override the built-in mutex logic must be 4860** prepared to accommodate additional static mutexes. 4861*/ 4862#define SQLITE_MUTEX_FAST 0 4863#define SQLITE_MUTEX_RECURSIVE 1 4864#define SQLITE_MUTEX_STATIC_MASTER 2 4865#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 4866#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 4867#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 4868#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 4869#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 4870#define SQLITE_MUTEX_STATIC_LRU2 7 /* lru page list */ 4871 4872/* 4873** CAPI3REF: Retrieve the mutex for a database connection {H17002} <H17000> 4874** 4875** This interface returns a pointer the [sqlite3_mutex] object that 4876** serializes access to the [database connection] given in the argument 4877** when the [threading mode] is Serialized. 4878** If the [threading mode] is Single-thread or Multi-thread then this 4879** routine returns a NULL pointer. 4880*/ 4881sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 4882 4883/* 4884** CAPI3REF: Low-Level Control Of Database Files {H11300} <S30800> 4885** 4886** {H11301} The [sqlite3_file_control()] interface makes a direct call to the 4887** xFileControl method for the [sqlite3_io_methods] object associated 4888** with a particular database identified by the second argument. {H11302} The 4889** name of the database is the name assigned to the database by the 4890** <a href="lang_attach.html">ATTACH</a> SQL command that opened the 4891** database. {H11303} To control the main database file, use the name "main" 4892** or a NULL pointer. {H11304} The third and fourth parameters to this routine 4893** are passed directly through to the second and third parameters of 4894** the xFileControl method. {H11305} The return value of the xFileControl 4895** method becomes the return value of this routine. 4896** 4897** {H11306} If the second parameter (zDbName) does not match the name of any 4898** open database file, then SQLITE_ERROR is returned. {H11307} This error 4899** code is not remembered and will not be recalled by [sqlite3_errcode()] 4900** or [sqlite3_errmsg()]. {A11308} The underlying xFileControl method might 4901** also return SQLITE_ERROR. {A11309} There is no way to distinguish between 4902** an incorrect zDbName and an SQLITE_ERROR return from the underlying 4903** xFileControl method. {END} 4904** 4905** See also: [SQLITE_FCNTL_LOCKSTATE] 4906*/ 4907int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 4908 4909/* 4910** CAPI3REF: Testing Interface {H11400} <S30800> 4911** 4912** The sqlite3_test_control() interface is used to read out internal 4913** state of SQLite and to inject faults into SQLite for testing 4914** purposes. The first parameter is an operation code that determines 4915** the number, meaning, and operation of all subsequent parameters. 4916** 4917** This interface is not for use by applications. It exists solely 4918** for verifying the correct operation of the SQLite library. Depending 4919** on how the SQLite library is compiled, this interface might not exist. 4920** 4921** The details of the operation codes, their meanings, the parameters 4922** they take, and what they do are all subject to change without notice. 4923** Unlike most of the SQLite API, this function is not guaranteed to 4924** operate consistently from one release to the next. 4925*/ 4926int sqlite3_test_control(int op, ...); 4927 4928/* 4929** CAPI3REF: Testing Interface Operation Codes {H11410} <H11400> 4930** 4931** These constants are the valid operation code parameters used 4932** as the first argument to [sqlite3_test_control()]. 4933** 4934** These parameters and their meanings are subject to change 4935** without notice. These values are for testing purposes only. 4936** Applications should not use any of these parameters or the 4937** [sqlite3_test_control()] interface. 4938*/ 4939#define SQLITE_TESTCTRL_PRNG_SAVE 5 4940#define SQLITE_TESTCTRL_PRNG_RESTORE 6 4941#define SQLITE_TESTCTRL_PRNG_RESET 7 4942#define SQLITE_TESTCTRL_BITVEC_TEST 8 4943#define SQLITE_TESTCTRL_FAULT_INSTALL 9 4944#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 4945#define SQLITE_TESTCTRL_PENDING_BYTE 11 4946#define SQLITE_TESTCTRL_ASSERT 12 4947#define SQLITE_TESTCTRL_ALWAYS 13 4948#define SQLITE_TESTCTRL_RESERVE 14 4949 4950/* 4951** CAPI3REF: SQLite Runtime Status {H17200} <S60200> 4952** EXPERIMENTAL 4953** 4954** This interface is used to retrieve runtime status information 4955** about the preformance of SQLite, and optionally to reset various 4956** highwater marks. The first argument is an integer code for 4957** the specific parameter to measure. Recognized integer codes 4958** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...]. 4959** The current value of the parameter is returned into *pCurrent. 4960** The highest recorded value is returned in *pHighwater. If the 4961** resetFlag is true, then the highest record value is reset after 4962** *pHighwater is written. Some parameters do not record the highest 4963** value. For those parameters 4964** nothing is written into *pHighwater and the resetFlag is ignored. 4965** Other parameters record only the highwater mark and not the current 4966** value. For these latter parameters nothing is written into *pCurrent. 4967** 4968** This routine returns SQLITE_OK on success and a non-zero 4969** [error code] on failure. 4970** 4971** This routine is threadsafe but is not atomic. This routine can 4972** called while other threads are running the same or different SQLite 4973** interfaces. However the values returned in *pCurrent and 4974** *pHighwater reflect the status of SQLite at different points in time 4975** and it is possible that another thread might change the parameter 4976** in between the times when *pCurrent and *pHighwater are written. 4977** 4978** See also: [sqlite3_db_status()] 4979*/ 4980SQLITE_EXPERIMENTAL int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 4981 4982 4983/* 4984** CAPI3REF: Status Parameters {H17250} <H17200> 4985** EXPERIMENTAL 4986** 4987** These integer constants designate various run-time status parameters 4988** that can be returned by [sqlite3_status()]. 4989** 4990** <dl> 4991** <dt>SQLITE_STATUS_MEMORY_USED</dt> 4992** <dd>This parameter is the current amount of memory checked out 4993** using [sqlite3_malloc()], either directly or indirectly. The 4994** figure includes calls made to [sqlite3_malloc()] by the application 4995** and internal memory usage by the SQLite library. Scratch memory 4996** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 4997** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 4998** this parameter. The amount returned is the sum of the allocation 4999** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd> 5000** 5001** <dt>SQLITE_STATUS_MALLOC_SIZE</dt> 5002** <dd>This parameter records the largest memory allocation request 5003** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 5004** internal equivalents). Only the value returned in the 5005** *pHighwater parameter to [sqlite3_status()] is of interest. 5006** The value written into the *pCurrent parameter is undefined.</dd> 5007** 5008** <dt>SQLITE_STATUS_PAGECACHE_USED</dt> 5009** <dd>This parameter returns the number of pages used out of the 5010** [pagecache memory allocator] that was configured using 5011** [SQLITE_CONFIG_PAGECACHE]. The 5012** value returned is in pages, not in bytes.</dd> 5013** 5014** <dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5015** <dd>This parameter returns the number of bytes of page cache 5016** allocation which could not be statisfied by the [SQLITE_CONFIG_PAGECACHE] 5017** buffer and where forced to overflow to [sqlite3_malloc()]. The 5018** returned value includes allocations that overflowed because they 5019** where too large (they were larger than the "sz" parameter to 5020** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 5021** no space was left in the page cache.</dd> 5022** 5023** <dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 5024** <dd>This parameter records the largest memory allocation request 5025** handed to [pagecache memory allocator]. Only the value returned in the 5026** *pHighwater parameter to [sqlite3_status()] is of interest. 5027** The value written into the *pCurrent parameter is undefined.</dd> 5028** 5029** <dt>SQLITE_STATUS_SCRATCH_USED</dt> 5030** <dd>This parameter returns the number of allocations used out of the 5031** [scratch memory allocator] configured using 5032** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5033** in bytes. Since a single thread may only have one scratch allocation 5034** outstanding at time, this parameter also reports the number of threads 5035** using scratch memory at the same time.</dd> 5036** 5037** <dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5038** <dd>This parameter returns the number of bytes of scratch memory 5039** allocation which could not be statisfied by the [SQLITE_CONFIG_SCRATCH] 5040** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5041** returned include overflows because the requested allocation was too 5042** larger (that is, because the requested allocation was larger than the 5043** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5044** slots were available. 5045** </dd> 5046** 5047** <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5048** <dd>This parameter records the largest memory allocation request 5049** handed to [scratch memory allocator]. Only the value returned in the 5050** *pHighwater parameter to [sqlite3_status()] is of interest. 5051** The value written into the *pCurrent parameter is undefined.</dd> 5052** 5053** <dt>SQLITE_STATUS_PARSER_STACK</dt> 5054** <dd>This parameter records the deepest parser stack. It is only 5055** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd> 5056** </dl> 5057** 5058** New status parameters may be added from time to time. 5059*/ 5060#define SQLITE_STATUS_MEMORY_USED 0 5061#define SQLITE_STATUS_PAGECACHE_USED 1 5062#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5063#define SQLITE_STATUS_SCRATCH_USED 3 5064#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5065#define SQLITE_STATUS_MALLOC_SIZE 5 5066#define SQLITE_STATUS_PARSER_STACK 6 5067#define SQLITE_STATUS_PAGECACHE_SIZE 7 5068#define SQLITE_STATUS_SCRATCH_SIZE 8 5069 5070/* 5071** CAPI3REF: Database Connection Status {H17500} <S60200> 5072** EXPERIMENTAL 5073** 5074** This interface is used to retrieve runtime status information 5075** about a single [database connection]. The first argument is the 5076** database connection object to be interrogated. The second argument 5077** is the parameter to interrogate. Currently, the only allowed value 5078** for the second parameter is [SQLITE_DBSTATUS_LOOKASIDE_USED]. 5079** Additional options will likely appear in future releases of SQLite. 5080** 5081** The current value of the requested parameter is written into *pCur 5082** and the highest instantaneous value is written into *pHiwtr. If 5083** the resetFlg is true, then the highest instantaneous value is 5084** reset back down to the current value. 5085** 5086** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5087*/ 5088SQLITE_EXPERIMENTAL int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5089 5090/* 5091** CAPI3REF: Status Parameters for database connections {H17520} <H17500> 5092** EXPERIMENTAL 5093** 5094** Status verbs for [sqlite3_db_status()]. 5095** 5096** <dl> 5097** <dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5098** <dd>This parameter returns the number of lookaside memory slots currently 5099** checked out.</dd> 5100** </dl> 5101*/ 5102#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 5103 5104 5105/* 5106** CAPI3REF: Prepared Statement Status {H17550} <S60200> 5107** EXPERIMENTAL 5108** 5109** Each prepared statement maintains various 5110** [SQLITE_STMTSTATUS_SORT | counters] that measure the number 5111** of times it has performed specific operations. These counters can 5112** be used to monitor the performance characteristics of the prepared 5113** statements. For example, if the number of table steps greatly exceeds 5114** the number of table searches or result rows, that would tend to indicate 5115** that the prepared statement is using a full table scan rather than 5116** an index. 5117** 5118** This interface is used to retrieve and reset counter values from 5119** a [prepared statement]. The first argument is the prepared statement 5120** object to be interrogated. The second argument 5121** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter] 5122** to be interrogated. 5123** The current value of the requested counter is returned. 5124** If the resetFlg is true, then the counter is reset to zero after this 5125** interface call returns. 5126** 5127** See also: [sqlite3_status()] and [sqlite3_db_status()]. 5128*/ 5129SQLITE_EXPERIMENTAL int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 5130 5131/* 5132** CAPI3REF: Status Parameters for prepared statements {H17570} <H17550> 5133** EXPERIMENTAL 5134** 5135** These preprocessor macros define integer codes that name counter 5136** values associated with the [sqlite3_stmt_status()] interface. 5137** The meanings of the various counters are as follows: 5138** 5139** <dl> 5140** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 5141** <dd>This is the number of times that SQLite has stepped forward in 5142** a table as part of a full table scan. Large numbers for this counter 5143** may indicate opportunities for performance improvement through 5144** careful use of indices.</dd> 5145** 5146** <dt>SQLITE_STMTSTATUS_SORT</dt> 5147** <dd>This is the number of sort operations that have occurred. 5148** A non-zero value in this counter may indicate an opportunity to 5149** improvement performance through careful use of indices.</dd> 5150** 5151** </dl> 5152*/ 5153#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 5154#define SQLITE_STMTSTATUS_SORT 2 5155 5156/* 5157** CAPI3REF: Custom Page Cache Object 5158** EXPERIMENTAL 5159** 5160** The sqlite3_pcache type is opaque. It is implemented by 5161** the pluggable module. The SQLite core has no knowledge of 5162** its size or internal structure and never deals with the 5163** sqlite3_pcache object except by holding and passing pointers 5164** to the object. 5165** 5166** See [sqlite3_pcache_methods] for additional information. 5167*/ 5168typedef struct sqlite3_pcache sqlite3_pcache; 5169 5170/* 5171** CAPI3REF: Application Defined Page Cache. 5172** EXPERIMENTAL 5173** 5174** The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can 5175** register an alternative page cache implementation by passing in an 5176** instance of the sqlite3_pcache_methods structure. The majority of the 5177** heap memory used by sqlite is used by the page cache to cache data read 5178** from, or ready to be written to, the database file. By implementing a 5179** custom page cache using this API, an application can control more 5180** precisely the amount of memory consumed by sqlite, the way in which 5181** said memory is allocated and released, and the policies used to 5182** determine exactly which parts of a database file are cached and for 5183** how long. 5184** 5185** The contents of the structure are copied to an internal buffer by sqlite 5186** within the call to [sqlite3_config]. 5187** 5188** The xInit() method is called once for each call to [sqlite3_initialize()] 5189** (usually only once during the lifetime of the process). It is passed 5190** a copy of the sqlite3_pcache_methods.pArg value. It can be used to set 5191** up global structures and mutexes required by the custom page cache 5192** implementation. The xShutdown() method is called from within 5193** [sqlite3_shutdown()], if the application invokes this API. It can be used 5194** to clean up any outstanding resources before process shutdown, if required. 5195** 5196** The xCreate() method is used to construct a new cache instance. The 5197** first parameter, szPage, is the size in bytes of the pages that must 5198** be allocated by the cache. szPage will not be a power of two. The 5199** second argument, bPurgeable, is true if the cache being created will 5200** be used to cache database pages read from a file stored on disk, or 5201** false if it is used for an in-memory database. The cache implementation 5202** does not have to do anything special based on the value of bPurgeable, 5203** it is purely advisory. 5204** 5205** The xCachesize() method may be called at any time by SQLite to set the 5206** suggested maximum cache-size (number of pages stored by) the cache 5207** instance passed as the first argument. This is the value configured using 5208** the SQLite "[PRAGMA cache_size]" command. As with the bPurgeable parameter, 5209** the implementation is not required to do anything special with this 5210** value, it is advisory only. 5211** 5212** The xPagecount() method should return the number of pages currently 5213** stored in the cache supplied as an argument. 5214** 5215** The xFetch() method is used to fetch a page and return a pointer to it. 5216** A 'page', in this context, is a buffer of szPage bytes aligned at an 5217** 8-byte boundary. The page to be fetched is determined by the key. The 5218** mimimum key value is 1. After it has been retrieved using xFetch, the page 5219** is considered to be pinned. 5220** 5221** If the requested page is already in the page cache, then a pointer to 5222** the cached buffer should be returned with its contents intact. If the 5223** page is not already in the cache, then the expected behaviour of the 5224** cache is determined by the value of the createFlag parameter passed 5225** to xFetch, according to the following table: 5226** 5227** <table border=1 width=85% align=center> 5228** <tr><th>createFlag<th>Expected Behaviour 5229** <tr><td>0<td>NULL should be returned. No new cache entry is created. 5230** <tr><td>1<td>If createFlag is set to 1, this indicates that 5231** SQLite is holding pinned pages that can be unpinned 5232** by writing their contents to the database file (a 5233** relatively expensive operation). In this situation the 5234** cache implementation has two choices: it can return NULL, 5235** in which case SQLite will attempt to unpin one or more 5236** pages before re-requesting the same page, or it can 5237** allocate a new page and return a pointer to it. If a new 5238** page is allocated, then the first sizeof(void*) bytes of 5239** it (at least) must be zeroed before it is returned. 5240** <tr><td>2<td>If createFlag is set to 2, then SQLite is not holding any 5241** pinned pages associated with the specific cache passed 5242** as the first argument to xFetch() that can be unpinned. The 5243** cache implementation should attempt to allocate a new 5244** cache entry and return a pointer to it. Again, the first 5245** sizeof(void*) bytes of the page should be zeroed before 5246** it is returned. If the xFetch() method returns NULL when 5247** createFlag==2, SQLite assumes that a memory allocation 5248** failed and returns SQLITE_NOMEM to the user. 5249** </table> 5250** 5251** xUnpin() is called by SQLite with a pointer to a currently pinned page 5252** as its second argument. If the third parameter, discard, is non-zero, 5253** then the page should be evicted from the cache. In this case SQLite 5254** assumes that the next time the page is retrieved from the cache using 5255** the xFetch() method, it will be zeroed. If the discard parameter is 5256** zero, then the page is considered to be unpinned. The cache implementation 5257** may choose to reclaim (free or recycle) unpinned pages at any time. 5258** SQLite assumes that next time the page is retrieved from the cache 5259** it will either be zeroed, or contain the same data that it did when it 5260** was unpinned. 5261** 5262** The cache is not required to perform any reference counting. A single 5263** call to xUnpin() unpins the page regardless of the number of prior calls 5264** to xFetch(). 5265** 5266** The xRekey() method is used to change the key value associated with the 5267** page passed as the second argument from oldKey to newKey. If the cache 5268** previously contains an entry associated with newKey, it should be 5269** discarded. Any prior cache entry associated with newKey is guaranteed not 5270** to be pinned. 5271** 5272** When SQLite calls the xTruncate() method, the cache must discard all 5273** existing cache entries with page numbers (keys) greater than or equal 5274** to the value of the iLimit parameter passed to xTruncate(). If any 5275** of these pages are pinned, they are implicitly unpinned, meaning that 5276** they can be safely discarded. 5277** 5278** The xDestroy() method is used to delete a cache allocated by xCreate(). 5279** All resources associated with the specified cache should be freed. After 5280** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 5281** handle invalid, and will not use it with any other sqlite3_pcache_methods 5282** functions. 5283*/ 5284typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 5285struct sqlite3_pcache_methods { 5286 void *pArg; 5287 int (*xInit)(void*); 5288 void (*xShutdown)(void*); 5289 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 5290 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 5291 int (*xPagecount)(sqlite3_pcache*); 5292 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 5293 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 5294 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 5295 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 5296 void (*xDestroy)(sqlite3_pcache*); 5297}; 5298 5299/* 5300** CAPI3REF: Online Backup Object 5301** EXPERIMENTAL 5302** 5303** The sqlite3_backup object records state information about an ongoing 5304** online backup operation. The sqlite3_backup object is created by 5305** a call to [sqlite3_backup_init()] and is destroyed by a call to 5306** [sqlite3_backup_finish()]. 5307** 5308** See Also: [Using the SQLite Online Backup API] 5309*/ 5310typedef struct sqlite3_backup sqlite3_backup; 5311 5312/* 5313** CAPI3REF: Online Backup API. 5314** EXPERIMENTAL 5315** 5316** This API is used to overwrite the contents of one database with that 5317** of another. It is useful either for creating backups of databases or 5318** for copying in-memory databases to or from persistent files. 5319** 5320** See Also: [Using the SQLite Online Backup API] 5321** 5322** Exclusive access is required to the destination database for the 5323** duration of the operation. However the source database is only 5324** read-locked while it is actually being read, it is not locked 5325** continuously for the entire operation. Thus, the backup may be 5326** performed on a live database without preventing other users from 5327** writing to the database for an extended period of time. 5328** 5329** To perform a backup operation: 5330** <ol> 5331** <li><b>sqlite3_backup_init()</b> is called once to initialize the 5332** backup, 5333** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 5334** the data between the two databases, and finally 5335** <li><b>sqlite3_backup_finish()</b> is called to release all resources 5336** associated with the backup operation. 5337** </ol> 5338** There should be exactly one call to sqlite3_backup_finish() for each 5339** successful call to sqlite3_backup_init(). 5340** 5341** <b>sqlite3_backup_init()</b> 5342** 5343** The first two arguments passed to [sqlite3_backup_init()] are the database 5344** handle associated with the destination database and the database name 5345** used to attach the destination database to the handle. The database name 5346** is "main" for the main database, "temp" for the temporary database, or 5347** the name specified as part of the [ATTACH] statement if the destination is 5348** an attached database. The third and fourth arguments passed to 5349** sqlite3_backup_init() identify the [database connection] 5350** and database name used 5351** to access the source database. The values passed for the source and 5352** destination [database connection] parameters must not be the same. 5353** 5354** If an error occurs within sqlite3_backup_init(), then NULL is returned 5355** and an error code and error message written into the [database connection] 5356** passed as the first argument. They may be retrieved using the 5357** [sqlite3_errcode()], [sqlite3_errmsg()], and [sqlite3_errmsg16()] functions. 5358** Otherwise, if successful, a pointer to an [sqlite3_backup] object is 5359** returned. This pointer may be used with the sqlite3_backup_step() and 5360** sqlite3_backup_finish() functions to perform the specified backup 5361** operation. 5362** 5363** <b>sqlite3_backup_step()</b> 5364** 5365** Function [sqlite3_backup_step()] is used to copy up to nPage pages between 5366** the source and destination databases, where nPage is the value of the 5367** second parameter passed to sqlite3_backup_step(). If nPage is a negative 5368** value, all remaining source pages are copied. If the required pages are 5369** succesfully copied, but there are still more pages to copy before the 5370** backup is complete, it returns [SQLITE_OK]. If no error occured and there 5371** are no more pages to copy, then [SQLITE_DONE] is returned. If an error 5372** occurs, then an SQLite error code is returned. As well as [SQLITE_OK] and 5373** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 5374** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 5375** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 5376** 5377** As well as the case where the destination database file was opened for 5378** read-only access, sqlite3_backup_step() may return [SQLITE_READONLY] if 5379** the destination is an in-memory database with a different page size 5380** from the source database. 5381** 5382** If sqlite3_backup_step() cannot obtain a required file-system lock, then 5383** the [sqlite3_busy_handler | busy-handler function] 5384** is invoked (if one is specified). If the 5385** busy-handler returns non-zero before the lock is available, then 5386** [SQLITE_BUSY] is returned to the caller. In this case the call to 5387** sqlite3_backup_step() can be retried later. If the source 5388** [database connection] 5389** is being used to write to the source database when sqlite3_backup_step() 5390** is called, then [SQLITE_LOCKED] is returned immediately. Again, in this 5391** case the call to sqlite3_backup_step() can be retried later on. If 5392** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 5393** [SQLITE_READONLY] is returned, then 5394** there is no point in retrying the call to sqlite3_backup_step(). These 5395** errors are considered fatal. At this point the application must accept 5396** that the backup operation has failed and pass the backup operation handle 5397** to the sqlite3_backup_finish() to release associated resources. 5398** 5399** Following the first call to sqlite3_backup_step(), an exclusive lock is 5400** obtained on the destination file. It is not released until either 5401** sqlite3_backup_finish() is called or the backup operation is complete 5402** and sqlite3_backup_step() returns [SQLITE_DONE]. Additionally, each time 5403** a call to sqlite3_backup_step() is made a [shared lock] is obtained on 5404** the source database file. This lock is released before the 5405** sqlite3_backup_step() call returns. Because the source database is not 5406** locked between calls to sqlite3_backup_step(), it may be modified mid-way 5407** through the backup procedure. If the source database is modified by an 5408** external process or via a database connection other than the one being 5409** used by the backup operation, then the backup will be transparently 5410** restarted by the next call to sqlite3_backup_step(). If the source 5411** database is modified by the using the same database connection as is used 5412** by the backup operation, then the backup database is transparently 5413** updated at the same time. 5414** 5415** <b>sqlite3_backup_finish()</b> 5416** 5417** Once sqlite3_backup_step() has returned [SQLITE_DONE], or when the 5418** application wishes to abandon the backup operation, the [sqlite3_backup] 5419** object should be passed to sqlite3_backup_finish(). This releases all 5420** resources associated with the backup operation. If sqlite3_backup_step() 5421** has not yet returned [SQLITE_DONE], then any active write-transaction on the 5422** destination database is rolled back. The [sqlite3_backup] object is invalid 5423** and may not be used following a call to sqlite3_backup_finish(). 5424** 5425** The value returned by sqlite3_backup_finish is [SQLITE_OK] if no error 5426** occurred, regardless or whether or not sqlite3_backup_step() was called 5427** a sufficient number of times to complete the backup operation. Or, if 5428** an out-of-memory condition or IO error occured during a call to 5429** sqlite3_backup_step() then [SQLITE_NOMEM] or an 5430** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] error code 5431** is returned. In this case the error code and an error message are 5432** written to the destination [database connection]. 5433** 5434** A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() is 5435** not a permanent error and does not affect the return value of 5436** sqlite3_backup_finish(). 5437** 5438** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b> 5439** 5440** Each call to sqlite3_backup_step() sets two values stored internally 5441** by an [sqlite3_backup] object. The number of pages still to be backed 5442** up, which may be queried by sqlite3_backup_remaining(), and the total 5443** number of pages in the source database file, which may be queried by 5444** sqlite3_backup_pagecount(). 5445** 5446** The values returned by these functions are only updated by 5447** sqlite3_backup_step(). If the source database is modified during a backup 5448** operation, then the values are not updated to account for any extra 5449** pages that need to be updated or the size of the source database file 5450** changing. 5451** 5452** <b>Concurrent Usage of Database Handles</b> 5453** 5454** The source [database connection] may be used by the application for other 5455** purposes while a backup operation is underway or being initialized. 5456** If SQLite is compiled and configured to support threadsafe database 5457** connections, then the source database connection may be used concurrently 5458** from within other threads. 5459** 5460** However, the application must guarantee that the destination database 5461** connection handle is not passed to any other API (by any thread) after 5462** sqlite3_backup_init() is called and before the corresponding call to 5463** sqlite3_backup_finish(). Unfortunately SQLite does not currently check 5464** for this, if the application does use the destination [database connection] 5465** for some other purpose during a backup operation, things may appear to 5466** work correctly but in fact be subtly malfunctioning. Use of the 5467** destination database connection while a backup is in progress might 5468** also cause a mutex deadlock. 5469** 5470** Furthermore, if running in [shared cache mode], the application must 5471** guarantee that the shared cache used by the destination database 5472** is not accessed while the backup is running. In practice this means 5473** that the application must guarantee that the file-system file being 5474** backed up to is not accessed by any connection within the process, 5475** not just the specific connection that was passed to sqlite3_backup_init(). 5476** 5477** The [sqlite3_backup] object itself is partially threadsafe. Multiple 5478** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 5479** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 5480** APIs are not strictly speaking threadsafe. If they are invoked at the 5481** same time as another thread is invoking sqlite3_backup_step() it is 5482** possible that they return invalid values. 5483*/ 5484sqlite3_backup *sqlite3_backup_init( 5485 sqlite3 *pDest, /* Destination database handle */ 5486 const char *zDestName, /* Destination database name */ 5487 sqlite3 *pSource, /* Source database handle */ 5488 const char *zSourceName /* Source database name */ 5489); 5490int sqlite3_backup_step(sqlite3_backup *p, int nPage); 5491int sqlite3_backup_finish(sqlite3_backup *p); 5492int sqlite3_backup_remaining(sqlite3_backup *p); 5493int sqlite3_backup_pagecount(sqlite3_backup *p); 5494 5495/* 5496** CAPI3REF: Unlock Notification 5497** EXPERIMENTAL 5498** 5499** When running in shared-cache mode, a database operation may fail with 5500** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 5501** individual tables within the shared-cache cannot be obtained. See 5502** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 5503** This API may be used to register a callback that SQLite will invoke 5504** when the connection currently holding the required lock relinquishes it. 5505** This API is only available if the library was compiled with the 5506** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 5507** 5508** See Also: [Using the SQLite Unlock Notification Feature]. 5509** 5510** Shared-cache locks are released when a database connection concludes 5511** its current transaction, either by committing it or rolling it back. 5512** 5513** When a connection (known as the blocked connection) fails to obtain a 5514** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 5515** identity of the database connection (the blocking connection) that 5516** has locked the required resource is stored internally. After an 5517** application receives an SQLITE_LOCKED error, it may call the 5518** sqlite3_unlock_notify() method with the blocked connection handle as 5519** the first argument to register for a callback that will be invoked 5520** when the blocking connections current transaction is concluded. The 5521** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 5522** call that concludes the blocking connections transaction. 5523** 5524** If sqlite3_unlock_notify() is called in a multi-threaded application, 5525** there is a chance that the blocking connection will have already 5526** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 5527** If this happens, then the specified callback is invoked immediately, 5528** from within the call to sqlite3_unlock_notify(). 5529** 5530** If the blocked connection is attempting to obtain a write-lock on a 5531** shared-cache table, and more than one other connection currently holds 5532** a read-lock on the same table, then SQLite arbitrarily selects one of 5533** the other connections to use as the blocking connection. 5534** 5535** There may be at most one unlock-notify callback registered by a 5536** blocked connection. If sqlite3_unlock_notify() is called when the 5537** blocked connection already has a registered unlock-notify callback, 5538** then the new callback replaces the old. If sqlite3_unlock_notify() is 5539** called with a NULL pointer as its second argument, then any existing 5540** unlock-notify callback is cancelled. The blocked connections 5541** unlock-notify callback may also be canceled by closing the blocked 5542** connection using [sqlite3_close()]. 5543** 5544** The unlock-notify callback is not reentrant. If an application invokes 5545** any sqlite3_xxx API functions from within an unlock-notify callback, a 5546** crash or deadlock may be the result. 5547** 5548** Unless deadlock is detected (see below), sqlite3_unlock_notify() always 5549** returns SQLITE_OK. 5550** 5551** <b>Callback Invocation Details</b> 5552** 5553** When an unlock-notify callback is registered, the application provides a 5554** single void* pointer that is passed to the callback when it is invoked. 5555** However, the signature of the callback function allows SQLite to pass 5556** it an array of void* context pointers. The first argument passed to 5557** an unlock-notify callback is a pointer to an array of void* pointers, 5558** and the second is the number of entries in the array. 5559** 5560** When a blocking connections transaction is concluded, there may be 5561** more than one blocked connection that has registered for an unlock-notify 5562** callback. If two or more such blocked connections have specified the 5563** same callback function, then instead of invoking the callback function 5564** multiple times, it is invoked once with the set of void* context pointers 5565** specified by the blocked connections bundled together into an array. 5566** This gives the application an opportunity to prioritize any actions 5567** related to the set of unblocked database connections. 5568** 5569** <b>Deadlock Detection</b> 5570** 5571** Assuming that after registering for an unlock-notify callback a 5572** database waits for the callback to be issued before taking any further 5573** action (a reasonable assumption), then using this API may cause the 5574** application to deadlock. For example, if connection X is waiting for 5575** connection Y's transaction to be concluded, and similarly connection 5576** Y is waiting on connection X's transaction, then neither connection 5577** will proceed and the system may remain deadlocked indefinitely. 5578** 5579** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 5580** detection. If a given call to sqlite3_unlock_notify() would put the 5581** system in a deadlocked state, then SQLITE_LOCKED is returned and no 5582** unlock-notify callback is registered. The system is said to be in 5583** a deadlocked state if connection A has registered for an unlock-notify 5584** callback on the conclusion of connection B's transaction, and connection 5585** B has itself registered for an unlock-notify callback when connection 5586** A's transaction is concluded. Indirect deadlock is also detected, so 5587** the system is also considered to be deadlocked if connection B has 5588** registered for an unlock-notify callback on the conclusion of connection 5589** C's transaction, where connection C is waiting on connection A. Any 5590** number of levels of indirection are allowed. 5591** 5592** <b>The "DROP TABLE" Exception</b> 5593** 5594** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 5595** always appropriate to call sqlite3_unlock_notify(). There is however, 5596** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 5597** SQLite checks if there are any currently executing SELECT statements 5598** that belong to the same connection. If there are, SQLITE_LOCKED is 5599** returned. In this case there is no "blocking connection", so invoking 5600** sqlite3_unlock_notify() results in the unlock-notify callback being 5601** invoked immediately. If the application then re-attempts the "DROP TABLE" 5602** or "DROP INDEX" query, an infinite loop might be the result. 5603** 5604** One way around this problem is to check the extended error code returned 5605** by an sqlite3_step() call. If there is a blocking connection, then the 5606** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 5607** the special "DROP TABLE/INDEX" case, the extended error code is just 5608** SQLITE_LOCKED. 5609*/ 5610int sqlite3_unlock_notify( 5611 sqlite3 *pBlocked, /* Waiting connection */ 5612 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 5613 void *pNotifyArg /* Argument to pass to xNotify */ 5614); 5615 5616/* 5617** Undo the hack that converts floating point types to integer for 5618** builds on processors without floating point support. 5619*/ 5620#ifdef SQLITE_OMIT_FLOATING_POINT 5621# undef double 5622#endif 5623 5624#ifdef __cplusplus 5625} /* End of the 'extern "C"' block */ 5626#endif 5627#endif 5628