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 1.451 2009/05/17 12:07:48 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** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 498** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 499** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 500** flag may be ORed in to indicate that only the data of the file 501** and not its inode needs to be synced. 502** 503** The integer values to xLock() and xUnlock() are one of 504** <ul> 505** <li> [SQLITE_LOCK_NONE], 506** <li> [SQLITE_LOCK_SHARED], 507** <li> [SQLITE_LOCK_RESERVED], 508** <li> [SQLITE_LOCK_PENDING], or 509** <li> [SQLITE_LOCK_EXCLUSIVE]. 510** </ul> 511** xLock() increases the lock. xUnlock() decreases the lock. 512** The xCheckReservedLock() method checks whether any database connection, 513** either in this process or in some other process, is holding a RESERVED, 514** PENDING, or EXCLUSIVE lock on the file. It returns true 515** if such a lock exists and false otherwise. 516** 517** The xFileControl() method is a generic interface that allows custom 518** VFS implementations to directly control an open file using the 519** [sqlite3_file_control()] interface. The second "op" argument is an 520** integer opcode. The third argument is a generic pointer intended to 521** point to a structure that may contain arguments or space in which to 522** write return values. Potential uses for xFileControl() might be 523** functions to enable blocking locks with timeouts, to change the 524** locking strategy (for example to use dot-file locks), to inquire 525** about the status of a lock, or to break stale locks. The SQLite 526** core reserves all opcodes less than 100 for its own use. 527** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 528** Applications that define a custom xFileControl method should use opcodes 529** greater than 100 to avoid conflicts. 530** 531** The xSectorSize() method returns the sector size of the 532** device that underlies the file. The sector size is the 533** minimum write that can be performed without disturbing 534** other bytes in the file. The xDeviceCharacteristics() 535** method returns a bit vector describing behaviors of the 536** underlying device: 537** 538** <ul> 539** <li> [SQLITE_IOCAP_ATOMIC] 540** <li> [SQLITE_IOCAP_ATOMIC512] 541** <li> [SQLITE_IOCAP_ATOMIC1K] 542** <li> [SQLITE_IOCAP_ATOMIC2K] 543** <li> [SQLITE_IOCAP_ATOMIC4K] 544** <li> [SQLITE_IOCAP_ATOMIC8K] 545** <li> [SQLITE_IOCAP_ATOMIC16K] 546** <li> [SQLITE_IOCAP_ATOMIC32K] 547** <li> [SQLITE_IOCAP_ATOMIC64K] 548** <li> [SQLITE_IOCAP_SAFE_APPEND] 549** <li> [SQLITE_IOCAP_SEQUENTIAL] 550** </ul> 551** 552** The SQLITE_IOCAP_ATOMIC property means that all writes of 553** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 554** mean that writes of blocks that are nnn bytes in size and 555** are aligned to an address which is an integer multiple of 556** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 557** that when data is appended to a file, the data is appended 558** first then the size of the file is extended, never the other 559** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 560** information is written to disk in the same order as calls 561** to xWrite(). 562** 563** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 564** in the unread portions of the buffer with zeros. A VFS that 565** fails to zero-fill short reads might seem to work. However, 566** failure to zero-fill short reads will eventually lead to 567** database corruption. 568*/ 569typedef struct sqlite3_io_methods sqlite3_io_methods; 570struct sqlite3_io_methods { 571 int iVersion; 572 int (*xClose)(sqlite3_file*); 573 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 574 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 575 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 576 int (*xSync)(sqlite3_file*, int flags); 577 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 578 int (*xLock)(sqlite3_file*, int); 579 int (*xUnlock)(sqlite3_file*, int); 580 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 581 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 582 int (*xSectorSize)(sqlite3_file*); 583 int (*xDeviceCharacteristics)(sqlite3_file*); 584 /* Additional methods may be added in future releases */ 585}; 586 587/* 588** CAPI3REF: Standard File Control Opcodes {H11310} <S30800> 589** 590** These integer constants are opcodes for the xFileControl method 591** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 592** interface. 593** 594** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 595** opcode causes the xFileControl method to write the current state of 596** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 597** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 598** into an integer that the pArg argument points to. This capability 599** is used during testing and only needs to be supported when SQLITE_TEST 600** is defined. 601*/ 602#define SQLITE_FCNTL_LOCKSTATE 1 603#define SQLITE_GET_LOCKPROXYFILE 2 604#define SQLITE_SET_LOCKPROXYFILE 3 605#define SQLITE_LAST_ERRNO 4 606 607/* 608** CAPI3REF: Mutex Handle {H17110} <S20130> 609** 610** The mutex module within SQLite defines [sqlite3_mutex] to be an 611** abstract type for a mutex object. The SQLite core never looks 612** at the internal representation of an [sqlite3_mutex]. It only 613** deals with pointers to the [sqlite3_mutex] object. 614** 615** Mutexes are created using [sqlite3_mutex_alloc()]. 616*/ 617typedef struct sqlite3_mutex sqlite3_mutex; 618 619/* 620** CAPI3REF: OS Interface Object {H11140} <S20100> 621** 622** An instance of the sqlite3_vfs object defines the interface between 623** the SQLite core and the underlying operating system. The "vfs" 624** in the name of the object stands for "virtual file system". 625** 626** The value of the iVersion field is initially 1 but may be larger in 627** future versions of SQLite. Additional fields may be appended to this 628** object when the iVersion value is increased. Note that the structure 629** of the sqlite3_vfs object changes in the transaction between 630** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 631** modified. 632** 633** The szOsFile field is the size of the subclassed [sqlite3_file] 634** structure used by this VFS. mxPathname is the maximum length of 635** a pathname in this VFS. 636** 637** Registered sqlite3_vfs objects are kept on a linked list formed by 638** the pNext pointer. The [sqlite3_vfs_register()] 639** and [sqlite3_vfs_unregister()] interfaces manage this list 640** in a thread-safe way. The [sqlite3_vfs_find()] interface 641** searches the list. Neither the application code nor the VFS 642** implementation should use the pNext pointer. 643** 644** The pNext field is the only field in the sqlite3_vfs 645** structure that SQLite will ever modify. SQLite will only access 646** or modify this field while holding a particular static mutex. 647** The application should never modify anything within the sqlite3_vfs 648** object once the object has been registered. 649** 650** The zName field holds the name of the VFS module. The name must 651** be unique across all VFS modules. 652** 653** SQLite will guarantee that the zFilename parameter to xOpen 654** is either a NULL pointer or string obtained 655** from xFullPathname(). SQLite further guarantees that 656** the string will be valid and unchanged until xClose() is 657** called. Because of the previous sentense, 658** the [sqlite3_file] can safely store a pointer to the 659** filename if it needs to remember the filename for some reason. 660** If the zFilename parameter is xOpen is a NULL pointer then xOpen 661** must invite its own temporary name for the file. Whenever the 662** xFilename parameter is NULL it will also be the case that the 663** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 664** 665** The flags argument to xOpen() includes all bits set in 666** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 667** or [sqlite3_open16()] is used, then flags includes at least 668** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 669** If xOpen() opens a file read-only then it sets *pOutFlags to 670** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 671** 672** SQLite will also add one of the following flags to the xOpen() 673** call, depending on the object being opened: 674** 675** <ul> 676** <li> [SQLITE_OPEN_MAIN_DB] 677** <li> [SQLITE_OPEN_MAIN_JOURNAL] 678** <li> [SQLITE_OPEN_TEMP_DB] 679** <li> [SQLITE_OPEN_TEMP_JOURNAL] 680** <li> [SQLITE_OPEN_TRANSIENT_DB] 681** <li> [SQLITE_OPEN_SUBJOURNAL] 682** <li> [SQLITE_OPEN_MASTER_JOURNAL] 683** </ul> 684** 685** The file I/O implementation can use the object type flags to 686** change the way it deals with files. For example, an application 687** that does not care about crash recovery or rollback might make 688** the open of a journal file a no-op. Writes to this journal would 689** also be no-ops, and any attempt to read the journal would return 690** SQLITE_IOERR. Or the implementation might recognize that a database 691** file will be doing page-aligned sector reads and writes in a random 692** order and set up its I/O subsystem accordingly. 693** 694** SQLite might also add one of the following flags to the xOpen method: 695** 696** <ul> 697** <li> [SQLITE_OPEN_DELETEONCLOSE] 698** <li> [SQLITE_OPEN_EXCLUSIVE] 699** </ul> 700** 701** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 702** deleted when it is closed. The [SQLITE_OPEN_DELETEONCLOSE] 703** will be set for TEMP databases, journals and for subjournals. 704** 705** The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 706** with the [SQLITE_OPEN_CREATE] flag, which are both directly 707** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 708** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 709** SQLITE_OPEN_CREATE, is used to indicate that file should always 710** be created, and that it is an error if it already exists. 711** It is <i>not</i> used to indicate the file should be opened 712** for exclusive access. 713** 714** At least szOsFile bytes of memory are allocated by SQLite 715** to hold the [sqlite3_file] structure passed as the third 716** argument to xOpen. The xOpen method does not have to 717** allocate the structure; it should just fill it in. 718** 719** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 720** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 721** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 722** to test whether a file is at least readable. The file can be a 723** directory. 724** 725** SQLite will always allocate at least mxPathname+1 bytes for the 726** output buffer xFullPathname. The exact size of the output buffer 727** is also passed as a parameter to both methods. If the output buffer 728** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 729** handled as a fatal error by SQLite, vfs implementations should endeavor 730** to prevent this by setting mxPathname to a sufficiently large value. 731** 732** The xRandomness(), xSleep(), and xCurrentTime() interfaces 733** are not strictly a part of the filesystem, but they are 734** included in the VFS structure for completeness. 735** The xRandomness() function attempts to return nBytes bytes 736** of good-quality randomness into zOut. The return value is 737** the actual number of bytes of randomness obtained. 738** The xSleep() method causes the calling thread to sleep for at 739** least the number of microseconds given. The xCurrentTime() 740** method returns a Julian Day Number for the current date and time. 741** 742*/ 743typedef struct sqlite3_vfs sqlite3_vfs; 744struct sqlite3_vfs { 745 int iVersion; /* Structure version number */ 746 int szOsFile; /* Size of subclassed sqlite3_file */ 747 int mxPathname; /* Maximum file pathname length */ 748 sqlite3_vfs *pNext; /* Next registered VFS */ 749 const char *zName; /* Name of this virtual file system */ 750 void *pAppData; /* Pointer to application-specific data */ 751 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 752 int flags, int *pOutFlags); 753 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 754 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 755 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 756 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 757 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 758 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 759 void (*xDlClose)(sqlite3_vfs*, void*); 760 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 761 int (*xSleep)(sqlite3_vfs*, int microseconds); 762 int (*xCurrentTime)(sqlite3_vfs*, double*); 763 int (*xGetLastError)(sqlite3_vfs*, int, char *); 764 /* New fields may be appended in figure versions. The iVersion 765 ** value will increment whenever this happens. */ 766}; 767 768/* 769** CAPI3REF: Flags for the xAccess VFS method {H11190} <H11140> 770** 771** These integer constants can be used as the third parameter to 772** the xAccess method of an [sqlite3_vfs] object. {END} They determine 773** what kind of permissions the xAccess method is looking for. 774** With SQLITE_ACCESS_EXISTS, the xAccess method 775** simply checks whether the file exists. 776** With SQLITE_ACCESS_READWRITE, the xAccess method 777** checks whether the file is both readable and writable. 778** With SQLITE_ACCESS_READ, the xAccess method 779** checks whether the file is readable. 780*/ 781#define SQLITE_ACCESS_EXISTS 0 782#define SQLITE_ACCESS_READWRITE 1 783#define SQLITE_ACCESS_READ 2 784 785/* 786** CAPI3REF: Initialize The SQLite Library {H10130} <S20000><S30100> 787** 788** The sqlite3_initialize() routine initializes the 789** SQLite library. The sqlite3_shutdown() routine 790** deallocates any resources that were allocated by sqlite3_initialize(). 791** 792** A call to sqlite3_initialize() is an "effective" call if it is 793** the first time sqlite3_initialize() is invoked during the lifetime of 794** the process, or if it is the first time sqlite3_initialize() is invoked 795** following a call to sqlite3_shutdown(). Only an effective call 796** of sqlite3_initialize() does any initialization. All other calls 797** are harmless no-ops. 798** 799** A call to sqlite3_shutdown() is an "effective" call if it is the first 800** call to sqlite3_shutdown() since the last sqlite3_initialize(). Only 801** an effective call to sqlite3_shutdown() does any deinitialization. 802** All other calls to sqlite3_shutdown() are harmless no-ops. 803** 804** Among other things, sqlite3_initialize() shall invoke 805** sqlite3_os_init(). Similarly, sqlite3_shutdown() 806** shall invoke sqlite3_os_end(). 807** 808** The sqlite3_initialize() routine returns [SQLITE_OK] on success. 809** If for some reason, sqlite3_initialize() is unable to initialize 810** the library (perhaps it is unable to allocate a needed resource such 811** as a mutex) it returns an [error code] other than [SQLITE_OK]. 812** 813** The sqlite3_initialize() routine is called internally by many other 814** SQLite interfaces so that an application usually does not need to 815** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 816** calls sqlite3_initialize() so the SQLite library will be automatically 817** initialized when [sqlite3_open()] is called if it has not be initialized 818** already. However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 819** compile-time option, then the automatic calls to sqlite3_initialize() 820** are omitted and the application must call sqlite3_initialize() directly 821** prior to using any other SQLite interface. For maximum portability, 822** it is recommended that applications always invoke sqlite3_initialize() 823** directly prior to using any other SQLite interface. Future releases 824** of SQLite may require this. In other words, the behavior exhibited 825** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 826** default behavior in some future release of SQLite. 827** 828** The sqlite3_os_init() routine does operating-system specific 829** initialization of the SQLite library. The sqlite3_os_end() 830** routine undoes the effect of sqlite3_os_init(). Typical tasks 831** performed by these routines include allocation or deallocation 832** of static resources, initialization of global variables, 833** setting up a default [sqlite3_vfs] module, or setting up 834** a default configuration using [sqlite3_config()]. 835** 836** The application should never invoke either sqlite3_os_init() 837** or sqlite3_os_end() directly. The application should only invoke 838** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 839** interface is called automatically by sqlite3_initialize() and 840** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 841** implementations for sqlite3_os_init() and sqlite3_os_end() 842** are built into SQLite when it is compiled for unix, windows, or os/2. 843** When built for other platforms (using the [SQLITE_OS_OTHER=1] compile-time 844** option) the application must supply a suitable implementation for 845** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 846** implementation of sqlite3_os_init() or sqlite3_os_end() 847** must return [SQLITE_OK] on success and some other [error code] upon 848** failure. 849*/ 850int sqlite3_initialize(void); 851int sqlite3_shutdown(void); 852int sqlite3_os_init(void); 853int sqlite3_os_end(void); 854 855/* 856** CAPI3REF: Configuring The SQLite Library {H14100} <S20000><S30200> 857** EXPERIMENTAL 858** 859** The sqlite3_config() interface is used to make global configuration 860** changes to SQLite in order to tune SQLite to the specific needs of 861** the application. The default configuration is recommended for most 862** applications and so this routine is usually not necessary. It is 863** provided to support rare applications with unusual needs. 864** 865** The sqlite3_config() interface is not threadsafe. The application 866** must insure that no other SQLite interfaces are invoked by other 867** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 868** may only be invoked prior to library initialization using 869** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 870** Note, however, that sqlite3_config() can be called as part of the 871** implementation of an application-defined [sqlite3_os_init()]. 872** 873** The first argument to sqlite3_config() is an integer 874** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines 875** what property of SQLite is to be configured. Subsequent arguments 876** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option] 877** in the first argument. 878** 879** When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 880** If the option is unknown or SQLite is unable to set the option 881** then this routine returns a non-zero [error code]. 882** 883** Requirements: 884** [H14103] [H14106] [H14120] [H14123] [H14126] [H14129] [H14132] [H14135] 885** [H14138] [H14141] [H14144] [H14147] [H14150] [H14153] [H14156] [H14159] 886** [H14162] [H14165] [H14168] 887*/ 888SQLITE_EXPERIMENTAL int sqlite3_config(int, ...); 889 890/* 891** CAPI3REF: Configure database connections {H14200} <S20000> 892** EXPERIMENTAL 893** 894** The sqlite3_db_config() interface is used to make configuration 895** changes to a [database connection]. The interface is similar to 896** [sqlite3_config()] except that the changes apply to a single 897** [database connection] (specified in the first argument). The 898** sqlite3_db_config() interface can only be used immediately after 899** the database connection is created using [sqlite3_open()], 900** [sqlite3_open16()], or [sqlite3_open_v2()]. 901** 902** The second argument to sqlite3_db_config(D,V,...) is the 903** configuration verb - an integer code that indicates what 904** aspect of the [database connection] is being configured. 905** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE]. 906** New verbs are likely to be added in future releases of SQLite. 907** Additional arguments depend on the verb. 908** 909** Requirements: 910** [H14203] [H14206] [H14209] [H14212] [H14215] 911*/ 912SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...); 913 914/* 915** CAPI3REF: Memory Allocation Routines {H10155} <S20120> 916** EXPERIMENTAL 917** 918** An instance of this object defines the interface between SQLite 919** and low-level memory allocation routines. 920** 921** This object is used in only one place in the SQLite interface. 922** A pointer to an instance of this object is the argument to 923** [sqlite3_config()] when the configuration option is 924** [SQLITE_CONFIG_MALLOC]. By creating an instance of this object 925** and passing it to [sqlite3_config()] during configuration, an 926** application can specify an alternative memory allocation subsystem 927** for SQLite to use for all of its dynamic memory needs. 928** 929** Note that SQLite comes with a built-in memory allocator that is 930** perfectly adequate for the overwhelming majority of applications 931** and that this object is only useful to a tiny minority of applications 932** with specialized memory allocation requirements. This object is 933** also used during testing of SQLite in order to specify an alternative 934** memory allocator that simulates memory out-of-memory conditions in 935** order to verify that SQLite recovers gracefully from such 936** conditions. 937** 938** The xMalloc, xFree, and xRealloc methods must work like the 939** malloc(), free(), and realloc() functions from the standard library. 940** 941** xSize should return the allocated size of a memory allocation 942** previously obtained from xMalloc or xRealloc. The allocated size 943** is always at least as big as the requested size but may be larger. 944** 945** The xRoundup method returns what would be the allocated size of 946** a memory allocation given a particular requested size. Most memory 947** allocators round up memory allocations at least to the next multiple 948** of 8. Some allocators round up to a larger multiple or to a power of 2. 949** 950** The xInit method initializes the memory allocator. (For example, 951** it might allocate any require mutexes or initialize internal data 952** structures. The xShutdown method is invoked (indirectly) by 953** [sqlite3_shutdown()] and should deallocate any resources acquired 954** by xInit. The pAppData pointer is used as the only parameter to 955** xInit and xShutdown. 956*/ 957typedef struct sqlite3_mem_methods sqlite3_mem_methods; 958struct sqlite3_mem_methods { 959 void *(*xMalloc)(int); /* Memory allocation function */ 960 void (*xFree)(void*); /* Free a prior allocation */ 961 void *(*xRealloc)(void*,int); /* Resize an allocation */ 962 int (*xSize)(void*); /* Return the size of an allocation */ 963 int (*xRoundup)(int); /* Round up request size to allocation size */ 964 int (*xInit)(void*); /* Initialize the memory allocator */ 965 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 966 void *pAppData; /* Argument to xInit() and xShutdown() */ 967}; 968 969/* 970** CAPI3REF: Configuration Options {H10160} <S20000> 971** EXPERIMENTAL 972** 973** These constants are the available integer configuration options that 974** can be passed as the first argument to the [sqlite3_config()] interface. 975** 976** New configuration options may be added in future releases of SQLite. 977** Existing configuration options might be discontinued. Applications 978** should check the return code from [sqlite3_config()] to make sure that 979** the call worked. The [sqlite3_config()] interface will return a 980** non-zero [error code] if a discontinued or unsupported configuration option 981** is invoked. 982** 983** <dl> 984** <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 985** <dd>There are no arguments to this option. This option disables 986** all mutexing and puts SQLite into a mode where it can only be used 987** by a single thread.</dd> 988** 989** <dt>SQLITE_CONFIG_MULTITHREAD</dt> 990** <dd>There are no arguments to this option. This option disables 991** mutexing on [database connection] and [prepared statement] objects. 992** The application is responsible for serializing access to 993** [database connections] and [prepared statements]. But other mutexes 994** are enabled so that SQLite will be safe to use in a multi-threaded 995** environment as long as no two threads attempt to use the same 996** [database connection] at the same time. See the [threading mode] 997** documentation for additional information.</dd> 998** 999** <dt>SQLITE_CONFIG_SERIALIZED</dt> 1000** <dd>There are no arguments to this option. This option enables 1001** all mutexes including the recursive 1002** mutexes on [database connection] and [prepared statement] objects. 1003** In this mode (which is the default when SQLite is compiled with 1004** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1005** to [database connections] and [prepared statements] so that the 1006** application is free to use the same [database connection] or the 1007** same [prepared statement] in different threads at the same time. 1008** See the [threading mode] documentation for additional information.</dd> 1009** 1010** <dt>SQLITE_CONFIG_MALLOC</dt> 1011** <dd>This option takes a single argument which is a pointer to an 1012** instance of the [sqlite3_mem_methods] structure. The argument specifies 1013** alternative low-level memory allocation routines to be used in place of 1014** the memory allocation routines built into SQLite.</dd> 1015** 1016** <dt>SQLITE_CONFIG_GETMALLOC</dt> 1017** <dd>This option takes a single argument which is a pointer to an 1018** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1019** structure is filled with the currently defined memory allocation routines. 1020** This option can be used to overload the default memory allocation 1021** routines with a wrapper that simulations memory allocation failure or 1022** tracks memory usage, for example.</dd> 1023** 1024** <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1025** <dd>This option takes single argument of type int, interpreted as a 1026** boolean, which enables or disables the collection of memory allocation 1027** statistics. When disabled, the following SQLite interfaces become 1028** non-operational: 1029** <ul> 1030** <li> [sqlite3_memory_used()] 1031** <li> [sqlite3_memory_highwater()] 1032** <li> [sqlite3_soft_heap_limit()] 1033** <li> [sqlite3_status()] 1034** </ul> 1035** </dd> 1036** 1037** <dt>SQLITE_CONFIG_SCRATCH</dt> 1038** <dd>This option specifies a static memory buffer that SQLite can use for 1039** scratch memory. There are three arguments: A pointer to the memory, the 1040** size of each scratch buffer (sz), and the number of buffers (N). The sz 1041** argument must be a multiple of 16. The sz parameter should be a few bytes 1042** larger than the actual scratch space required due internal overhead. 1043** The first 1044** argument should point to an allocation of at least sz*N bytes of memory. 1045** SQLite will use no more than one scratch buffer at once per thread, so 1046** N should be set to the expected maximum number of threads. The sz 1047** parameter should be 6 times the size of the largest database page size. 1048** Scratch buffers are used as part of the btree balance operation. If 1049** The btree balancer needs additional memory beyond what is provided by 1050** scratch buffers or if no scratch buffer space is specified, then SQLite 1051** goes to [sqlite3_malloc()] to obtain the memory it needs.</dd> 1052** 1053** <dt>SQLITE_CONFIG_PAGECACHE</dt> 1054** <dd>This option specifies a static memory buffer that SQLite can use for 1055** the database page cache with the default page cache implemenation. 1056** This configuration should not be used if an application-define page 1057** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option. 1058** There are three arguments to this option: A pointer to the 1059** memory, the size of each page buffer (sz), and the number of pages (N). 1060** The sz argument must be a power of two between 512 and 32768. The first 1061** argument should point to an allocation of at least sz*N bytes of memory. 1062** SQLite will use the memory provided by the first argument to satisfy its 1063** memory needs for the first N pages that it adds to cache. If additional 1064** page cache memory is needed beyond what is provided by this option, then 1065** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1066** The implementation might use one or more of the N buffers to hold 1067** memory accounting information. </dd> 1068** 1069** <dt>SQLITE_CONFIG_HEAP</dt> 1070** <dd>This option specifies a static memory buffer that SQLite will use 1071** for all of its dynamic memory allocation needs beyond those provided 1072** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1073** There are three arguments: A pointer to the memory, the number of 1074** bytes in the memory buffer, and the minimum allocation size. If 1075** the first pointer (the memory pointer) is NULL, then SQLite reverts 1076** to using its default memory allocator (the system malloc() implementation), 1077** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. If the 1078** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1079** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1080** allocator is engaged to handle all of SQLites memory allocation needs.</dd> 1081** 1082** <dt>SQLITE_CONFIG_MUTEX</dt> 1083** <dd>This option takes a single argument which is a pointer to an 1084** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1085** alternative low-level mutex routines to be used in place 1086** the mutex routines built into SQLite.</dd> 1087** 1088** <dt>SQLITE_CONFIG_GETMUTEX</dt> 1089** <dd>This option takes a single argument which is a pointer to an 1090** instance of the [sqlite3_mutex_methods] structure. The 1091** [sqlite3_mutex_methods] 1092** structure is filled with the currently defined mutex routines. 1093** This option can be used to overload the default mutex allocation 1094** routines with a wrapper used to track mutex usage for performance 1095** profiling or testing, for example.</dd> 1096** 1097** <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1098** <dd>This option takes two arguments that determine the default 1099** memory allcation lookaside optimization. The first argument is the 1100** size of each lookaside buffer slot and the second is the number of 1101** slots allocated to each database connection.</dd> 1102** 1103** <dt>SQLITE_CONFIG_PCACHE</dt> 1104** <dd>This option takes a single argument which is a pointer to 1105** an [sqlite3_pcache_methods] object. This object specifies the interface 1106** to a custom page cache implementation. SQLite makes a copy of the 1107** object and uses it for page cache memory allocations.</dd> 1108** 1109** <dt>SQLITE_CONFIG_GETPCACHE</dt> 1110** <dd>This option takes a single argument which is a pointer to an 1111** [sqlite3_pcache_methods] object. SQLite copies of the current 1112** page cache implementation into that object.</dd> 1113** 1114** </dl> 1115*/ 1116#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1117#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1118#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1119#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1120#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1121#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1122#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1123#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1124#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1125#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1126#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1127/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1128#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1129#define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */ 1130#define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */ 1131 1132/* 1133** CAPI3REF: Configuration Options {H10170} <S20000> 1134** EXPERIMENTAL 1135** 1136** These constants are the available integer configuration options that 1137** can be passed as the second argument to the [sqlite3_db_config()] interface. 1138** 1139** New configuration options may be added in future releases of SQLite. 1140** Existing configuration options might be discontinued. Applications 1141** should check the return code from [sqlite3_db_config()] to make sure that 1142** the call worked. The [sqlite3_db_config()] interface will return a 1143** non-zero [error code] if a discontinued or unsupported configuration option 1144** is invoked. 1145** 1146** <dl> 1147** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1148** <dd>This option takes three additional arguments that determine the 1149** [lookaside memory allocator] configuration for the [database connection]. 1150** The first argument (the third parameter to [sqlite3_db_config()] is a 1151** pointer to a memory buffer to use for lookaside memory. The first 1152** argument may be NULL in which case SQLite will allocate the lookaside 1153** buffer itself using [sqlite3_malloc()]. The second argument is the 1154** size of each lookaside buffer slot and the third argument is the number of 1155** slots. The size of the buffer in the first argument must be greater than 1156** or equal to the product of the second and third arguments.</dd> 1157** 1158** </dl> 1159*/ 1160#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1161 1162 1163/* 1164** CAPI3REF: Enable Or Disable Extended Result Codes {H12200} <S10700> 1165** 1166** The sqlite3_extended_result_codes() routine enables or disables the 1167** [extended result codes] feature of SQLite. The extended result 1168** codes are disabled by default for historical compatibility considerations. 1169** 1170** Requirements: 1171** [H12201] [H12202] 1172*/ 1173int sqlite3_extended_result_codes(sqlite3*, int onoff); 1174 1175/* 1176** CAPI3REF: Last Insert Rowid {H12220} <S10700> 1177** 1178** Each entry in an SQLite table has a unique 64-bit signed 1179** integer key called the [ROWID | "rowid"]. The rowid is always available 1180** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1181** names are not also used by explicitly declared columns. If 1182** the table has a column of type [INTEGER PRIMARY KEY] then that column 1183** is another alias for the rowid. 1184** 1185** This routine returns the [rowid] of the most recent 1186** successful [INSERT] into the database from the [database connection] 1187** in the first argument. If no successful [INSERT]s 1188** have ever occurred on that database connection, zero is returned. 1189** 1190** If an [INSERT] occurs within a trigger, then the [rowid] of the inserted 1191** row is returned by this routine as long as the trigger is running. 1192** But once the trigger terminates, the value returned by this routine 1193** reverts to the last value inserted before the trigger fired. 1194** 1195** An [INSERT] that fails due to a constraint violation is not a 1196** successful [INSERT] and does not change the value returned by this 1197** routine. Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1198** and INSERT OR ABORT make no changes to the return value of this 1199** routine when their insertion fails. When INSERT OR REPLACE 1200** encounters a constraint violation, it does not fail. The 1201** INSERT continues to completion after deleting rows that caused 1202** the constraint problem so INSERT OR REPLACE will always change 1203** the return value of this interface. 1204** 1205** For the purposes of this routine, an [INSERT] is considered to 1206** be successful even if it is subsequently rolled back. 1207** 1208** Requirements: 1209** [H12221] [H12223] 1210** 1211** If a separate thread performs a new [INSERT] on the same 1212** database connection while the [sqlite3_last_insert_rowid()] 1213** function is running and thus changes the last insert [rowid], 1214** then the value returned by [sqlite3_last_insert_rowid()] is 1215** unpredictable and might not equal either the old or the new 1216** last insert [rowid]. 1217*/ 1218sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1219 1220/* 1221** CAPI3REF: Count The Number Of Rows Modified {H12240} <S10600> 1222** 1223** This function returns the number of database rows that were changed 1224** or inserted or deleted by the most recently completed SQL statement 1225** on the [database connection] specified by the first parameter. 1226** Only changes that are directly specified by the [INSERT], [UPDATE], 1227** or [DELETE] statement are counted. Auxiliary changes caused by 1228** triggers are not counted. Use the [sqlite3_total_changes()] function 1229** to find the total number of changes including changes caused by triggers. 1230** 1231** Changes to a view that are simulated by an [INSTEAD OF trigger] 1232** are not counted. Only real table changes are counted. 1233** 1234** A "row change" is a change to a single row of a single table 1235** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1236** are changed as side effects of [REPLACE] constraint resolution, 1237** rollback, ABORT processing, [DROP TABLE], or by any other 1238** mechanisms do not count as direct row changes. 1239** 1240** A "trigger context" is a scope of execution that begins and 1241** ends with the script of a [CREATE TRIGGER | trigger]. 1242** Most SQL statements are 1243** evaluated outside of any trigger. This is the "top level" 1244** trigger context. If a trigger fires from the top level, a 1245** new trigger context is entered for the duration of that one 1246** trigger. Subtriggers create subcontexts for their duration. 1247** 1248** Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1249** not create a new trigger context. 1250** 1251** This function returns the number of direct row changes in the 1252** most recent INSERT, UPDATE, or DELETE statement within the same 1253** trigger context. 1254** 1255** Thus, when called from the top level, this function returns the 1256** number of changes in the most recent INSERT, UPDATE, or DELETE 1257** that also occurred at the top level. Within the body of a trigger, 1258** the sqlite3_changes() interface can be called to find the number of 1259** changes in the most recently completed INSERT, UPDATE, or DELETE 1260** statement within the body of the same trigger. 1261** However, the number returned does not include changes 1262** caused by subtriggers since those have their own context. 1263** 1264** See also the [sqlite3_total_changes()] interface and the 1265** [count_changes pragma]. 1266** 1267** Requirements: 1268** [H12241] [H12243] 1269** 1270** If a separate thread makes changes on the same database connection 1271** while [sqlite3_changes()] is running then the value returned 1272** is unpredictable and not meaningful. 1273*/ 1274int sqlite3_changes(sqlite3*); 1275 1276/* 1277** CAPI3REF: Total Number Of Rows Modified {H12260} <S10600> 1278** 1279** This function returns the number of row changes caused by [INSERT], 1280** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1281** The count includes all changes from all 1282** [CREATE TRIGGER | trigger] contexts. However, 1283** the count does not include changes used to implement [REPLACE] constraints, 1284** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1285** count does not rows of views that fire an [INSTEAD OF trigger], though if 1286** the INSTEAD OF trigger makes changes of its own, those changes are 1287** counted. 1288** The changes are counted as soon as the statement that makes them is 1289** completed (when the statement handle is passed to [sqlite3_reset()] or 1290** [sqlite3_finalize()]). 1291** 1292** See also the [sqlite3_changes()] interface and the 1293** [count_changes pragma]. 1294** 1295** Requirements: 1296** [H12261] [H12263] 1297** 1298** If a separate thread makes changes on the same database connection 1299** while [sqlite3_total_changes()] is running then the value 1300** returned is unpredictable and not meaningful. 1301*/ 1302int sqlite3_total_changes(sqlite3*); 1303 1304/* 1305** CAPI3REF: Interrupt A Long-Running Query {H12270} <S30500> 1306** 1307** This function causes any pending database operation to abort and 1308** return at its earliest opportunity. This routine is typically 1309** called in response to a user action such as pressing "Cancel" 1310** or Ctrl-C where the user wants a long query operation to halt 1311** immediately. 1312** 1313** It is safe to call this routine from a thread different from the 1314** thread that is currently running the database operation. But it 1315** is not safe to call this routine with a [database connection] that 1316** is closed or might close before sqlite3_interrupt() returns. 1317** 1318** If an SQL operation is very nearly finished at the time when 1319** sqlite3_interrupt() is called, then it might not have an opportunity 1320** to be interrupted and might continue to completion. 1321** 1322** An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1323** If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1324** that is inside an explicit transaction, then the entire transaction 1325** will be rolled back automatically. 1326** 1327** The sqlite3_interrupt(D) call is in effect until all currently running 1328** SQL statements on [database connection] D complete. Any new SQL statements 1329** that are started after the sqlite3_interrupt() call and before the 1330** running statements reaches zero are interrupted as if they had been 1331** running prior to the sqlite3_interrupt() call. New SQL statements 1332** that are started after the running statement count reaches zero are 1333** not effected by the sqlite3_interrupt(). 1334** A call to sqlite3_interrupt(D) that occurs when there are no running 1335** SQL statements is a no-op and has no effect on SQL statements 1336** that are started after the sqlite3_interrupt() call returns. 1337** 1338** Requirements: 1339** [H12271] [H12272] 1340** 1341** If the database connection closes while [sqlite3_interrupt()] 1342** is running then bad things will likely happen. 1343*/ 1344void sqlite3_interrupt(sqlite3*); 1345 1346/* 1347** CAPI3REF: Determine If An SQL Statement Is Complete {H10510} <S70200> 1348** 1349** These routines are useful during command-line input to determine if the 1350** currently entered text seems to form a complete SQL statement or 1351** if additional input is needed before sending the text into 1352** SQLite for parsing. These routines return 1 if the input string 1353** appears to be a complete SQL statement. A statement is judged to be 1354** complete if it ends with a semicolon token and is not a prefix of a 1355** well-formed CREATE TRIGGER statement. Semicolons that are embedded within 1356** string literals or quoted identifier names or comments are not 1357** independent tokens (they are part of the token in which they are 1358** embedded) and thus do not count as a statement terminator. Whitespace 1359** and comments that follow the final semicolon are ignored. 1360** 1361** These routines return 0 if the statement is incomplete. If a 1362** memory allocation fails, then SQLITE_NOMEM is returned. 1363** 1364** These routines do not parse the SQL statements thus 1365** will not detect syntactically incorrect SQL. 1366** 1367** If SQLite has not been initialized using [sqlite3_initialize()] prior 1368** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1369** automatically by sqlite3_complete16(). If that initialization fails, 1370** then the return value from sqlite3_complete16() will be non-zero 1371** regardless of whether or not the input SQL is complete. 1372** 1373** Requirements: [H10511] [H10512] 1374** 1375** The input to [sqlite3_complete()] must be a zero-terminated 1376** UTF-8 string. 1377** 1378** The input to [sqlite3_complete16()] must be a zero-terminated 1379** UTF-16 string in native byte order. 1380*/ 1381int sqlite3_complete(const char *sql); 1382int sqlite3_complete16(const void *sql); 1383 1384/* 1385** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors {H12310} <S40400> 1386** 1387** This routine sets a callback function that might be invoked whenever 1388** an attempt is made to open a database table that another thread 1389** or process has locked. 1390** 1391** If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1392** is returned immediately upon encountering the lock. If the busy callback 1393** is not NULL, then the callback will be invoked with two arguments. 1394** 1395** The first argument to the handler is a copy of the void* pointer which 1396** is the third argument to sqlite3_busy_handler(). The second argument to 1397** the handler callback is the number of times that the busy handler has 1398** been invoked for this locking event. If the 1399** busy callback returns 0, then no additional attempts are made to 1400** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1401** If the callback returns non-zero, then another attempt 1402** is made to open the database for reading and the cycle repeats. 1403** 1404** The presence of a busy handler does not guarantee that it will be invoked 1405** when there is lock contention. If SQLite determines that invoking the busy 1406** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1407** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1408** Consider a scenario where one process is holding a read lock that 1409** it is trying to promote to a reserved lock and 1410** a second process is holding a reserved lock that it is trying 1411** to promote to an exclusive lock. The first process cannot proceed 1412** because it is blocked by the second and the second process cannot 1413** proceed because it is blocked by the first. If both processes 1414** invoke the busy handlers, neither will make any progress. Therefore, 1415** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1416** will induce the first process to release its read lock and allow 1417** the second process to proceed. 1418** 1419** The default busy callback is NULL. 1420** 1421** The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1422** when SQLite is in the middle of a large transaction where all the 1423** changes will not fit into the in-memory cache. SQLite will 1424** already hold a RESERVED lock on the database file, but it needs 1425** to promote this lock to EXCLUSIVE so that it can spill cache 1426** pages into the database file without harm to concurrent 1427** readers. If it is unable to promote the lock, then the in-memory 1428** cache will be left in an inconsistent state and so the error 1429** code is promoted from the relatively benign [SQLITE_BUSY] to 1430** the more severe [SQLITE_IOERR_BLOCKED]. This error code promotion 1431** forces an automatic rollback of the changes. See the 1432** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1433** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1434** this is important. 1435** 1436** There can only be a single busy handler defined for each 1437** [database connection]. Setting a new busy handler clears any 1438** previously set handler. Note that calling [sqlite3_busy_timeout()] 1439** will also set or clear the busy handler. 1440** 1441** The busy callback should not take any actions which modify the 1442** database connection that invoked the busy handler. Any such actions 1443** result in undefined behavior. 1444** 1445** Requirements: 1446** [H12311] [H12312] [H12314] [H12316] [H12318] 1447** 1448** A busy handler must not close the database connection 1449** or [prepared statement] that invoked the busy handler. 1450*/ 1451int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1452 1453/* 1454** CAPI3REF: Set A Busy Timeout {H12340} <S40410> 1455** 1456** This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1457** for a specified amount of time when a table is locked. The handler 1458** will sleep multiple times until at least "ms" milliseconds of sleeping 1459** have accumulated. {H12343} After "ms" milliseconds of sleeping, 1460** the handler returns 0 which causes [sqlite3_step()] to return 1461** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1462** 1463** Calling this routine with an argument less than or equal to zero 1464** turns off all busy handlers. 1465** 1466** There can only be a single busy handler for a particular 1467** [database connection] any any given moment. If another busy handler 1468** was defined (using [sqlite3_busy_handler()]) prior to calling 1469** this routine, that other busy handler is cleared. 1470** 1471** Requirements: 1472** [H12341] [H12343] [H12344] 1473*/ 1474int sqlite3_busy_timeout(sqlite3*, int ms); 1475 1476/* 1477** CAPI3REF: Convenience Routines For Running Queries {H12370} <S10000> 1478** 1479** Definition: A <b>result table</b> is memory data structure created by the 1480** [sqlite3_get_table()] interface. A result table records the 1481** complete query results from one or more queries. 1482** 1483** The table conceptually has a number of rows and columns. But 1484** these numbers are not part of the result table itself. These 1485** numbers are obtained separately. Let N be the number of rows 1486** and M be the number of columns. 1487** 1488** A result table is an array of pointers to zero-terminated UTF-8 strings. 1489** There are (N+1)*M elements in the array. The first M pointers point 1490** to zero-terminated strings that contain the names of the columns. 1491** The remaining entries all point to query results. NULL values result 1492** in NULL pointers. All other values are in their UTF-8 zero-terminated 1493** string representation as returned by [sqlite3_column_text()]. 1494** 1495** A result table might consist of one or more memory allocations. 1496** It is not safe to pass a result table directly to [sqlite3_free()]. 1497** A result table should be deallocated using [sqlite3_free_table()]. 1498** 1499** As an example of the result table format, suppose a query result 1500** is as follows: 1501** 1502** <blockquote><pre> 1503** Name | Age 1504** ----------------------- 1505** Alice | 43 1506** Bob | 28 1507** Cindy | 21 1508** </pre></blockquote> 1509** 1510** There are two column (M==2) and three rows (N==3). Thus the 1511** result table has 8 entries. Suppose the result table is stored 1512** in an array names azResult. Then azResult holds this content: 1513** 1514** <blockquote><pre> 1515** azResult[0] = "Name"; 1516** azResult[1] = "Age"; 1517** azResult[2] = "Alice"; 1518** azResult[3] = "43"; 1519** azResult[4] = "Bob"; 1520** azResult[5] = "28"; 1521** azResult[6] = "Cindy"; 1522** azResult[7] = "21"; 1523** </pre></blockquote> 1524** 1525** The sqlite3_get_table() function evaluates one or more 1526** semicolon-separated SQL statements in the zero-terminated UTF-8 1527** string of its 2nd parameter. It returns a result table to the 1528** pointer given in its 3rd parameter. 1529** 1530** After the calling function has finished using the result, it should 1531** pass the pointer to the result table to sqlite3_free_table() in order to 1532** release the memory that was malloced. Because of the way the 1533** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1534** function must not try to call [sqlite3_free()] directly. Only 1535** [sqlite3_free_table()] is able to release the memory properly and safely. 1536** 1537** The sqlite3_get_table() interface is implemented as a wrapper around 1538** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 1539** to any internal data structures of SQLite. It uses only the public 1540** interface defined here. As a consequence, errors that occur in the 1541** wrapper layer outside of the internal [sqlite3_exec()] call are not 1542** reflected in subsequent calls to [sqlite3_errcode()] or [sqlite3_errmsg()]. 1543** 1544** Requirements: 1545** [H12371] [H12373] [H12374] [H12376] [H12379] [H12382] 1546*/ 1547int sqlite3_get_table( 1548 sqlite3 *db, /* An open database */ 1549 const char *zSql, /* SQL to be evaluated */ 1550 char ***pazResult, /* Results of the query */ 1551 int *pnRow, /* Number of result rows written here */ 1552 int *pnColumn, /* Number of result columns written here */ 1553 char **pzErrmsg /* Error msg written here */ 1554); 1555void sqlite3_free_table(char **result); 1556 1557/* 1558** CAPI3REF: Formatted String Printing Functions {H17400} <S70000><S20000> 1559** 1560** These routines are workalikes of the "printf()" family of functions 1561** from the standard C library. 1562** 1563** The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 1564** results into memory obtained from [sqlite3_malloc()]. 1565** The strings returned by these two routines should be 1566** released by [sqlite3_free()]. Both routines return a 1567** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 1568** memory to hold the resulting string. 1569** 1570** In sqlite3_snprintf() routine is similar to "snprintf()" from 1571** the standard C library. The result is written into the 1572** buffer supplied as the second parameter whose size is given by 1573** the first parameter. Note that the order of the 1574** first two parameters is reversed from snprintf(). This is an 1575** historical accident that cannot be fixed without breaking 1576** backwards compatibility. Note also that sqlite3_snprintf() 1577** returns a pointer to its buffer instead of the number of 1578** characters actually written into the buffer. We admit that 1579** the number of characters written would be a more useful return 1580** value but we cannot change the implementation of sqlite3_snprintf() 1581** now without breaking compatibility. 1582** 1583** As long as the buffer size is greater than zero, sqlite3_snprintf() 1584** guarantees that the buffer is always zero-terminated. The first 1585** parameter "n" is the total size of the buffer, including space for 1586** the zero terminator. So the longest string that can be completely 1587** written will be n-1 characters. 1588** 1589** These routines all implement some additional formatting 1590** options that are useful for constructing SQL statements. 1591** All of the usual printf() formatting options apply. In addition, there 1592** is are "%q", "%Q", and "%z" options. 1593** 1594** The %q option works like %s in that it substitutes a null-terminated 1595** string from the argument list. But %q also doubles every '\'' character. 1596** %q is designed for use inside a string literal. By doubling each '\'' 1597** character it escapes that character and allows it to be inserted into 1598** the string. 1599** 1600** For example, assume the string variable zText contains text as follows: 1601** 1602** <blockquote><pre> 1603** char *zText = "It's a happy day!"; 1604** </pre></blockquote> 1605** 1606** One can use this text in an SQL statement as follows: 1607** 1608** <blockquote><pre> 1609** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 1610** sqlite3_exec(db, zSQL, 0, 0, 0); 1611** sqlite3_free(zSQL); 1612** </pre></blockquote> 1613** 1614** Because the %q format string is used, the '\'' character in zText 1615** is escaped and the SQL generated is as follows: 1616** 1617** <blockquote><pre> 1618** INSERT INTO table1 VALUES('It''s a happy day!') 1619** </pre></blockquote> 1620** 1621** This is correct. Had we used %s instead of %q, the generated SQL 1622** would have looked like this: 1623** 1624** <blockquote><pre> 1625** INSERT INTO table1 VALUES('It's a happy day!'); 1626** </pre></blockquote> 1627** 1628** This second example is an SQL syntax error. As a general rule you should 1629** always use %q instead of %s when inserting text into a string literal. 1630** 1631** The %Q option works like %q except it also adds single quotes around 1632** the outside of the total string. Additionally, if the parameter in the 1633** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 1634** single quotes) in place of the %Q option. So, for example, one could say: 1635** 1636** <blockquote><pre> 1637** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 1638** sqlite3_exec(db, zSQL, 0, 0, 0); 1639** sqlite3_free(zSQL); 1640** </pre></blockquote> 1641** 1642** The code above will render a correct SQL statement in the zSQL 1643** variable even if the zText variable is a NULL pointer. 1644** 1645** The "%z" formatting option works exactly like "%s" with the 1646** addition that after the string has been read and copied into 1647** the result, [sqlite3_free()] is called on the input string. {END} 1648** 1649** Requirements: 1650** [H17403] [H17406] [H17407] 1651*/ 1652char *sqlite3_mprintf(const char*,...); 1653char *sqlite3_vmprintf(const char*, va_list); 1654char *sqlite3_snprintf(int,char*,const char*, ...); 1655 1656/* 1657** CAPI3REF: Memory Allocation Subsystem {H17300} <S20000> 1658** 1659** The SQLite core uses these three routines for all of its own 1660** internal memory allocation needs. "Core" in the previous sentence 1661** does not include operating-system specific VFS implementation. The 1662** Windows VFS uses native malloc() and free() for some operations. 1663** 1664** The sqlite3_malloc() routine returns a pointer to a block 1665** of memory at least N bytes in length, where N is the parameter. 1666** If sqlite3_malloc() is unable to obtain sufficient free 1667** memory, it returns a NULL pointer. If the parameter N to 1668** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 1669** a NULL pointer. 1670** 1671** Calling sqlite3_free() with a pointer previously returned 1672** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 1673** that it might be reused. The sqlite3_free() routine is 1674** a no-op if is called with a NULL pointer. Passing a NULL pointer 1675** to sqlite3_free() is harmless. After being freed, memory 1676** should neither be read nor written. Even reading previously freed 1677** memory might result in a segmentation fault or other severe error. 1678** Memory corruption, a segmentation fault, or other severe error 1679** might result if sqlite3_free() is called with a non-NULL pointer that 1680** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 1681** 1682** The sqlite3_realloc() interface attempts to resize a 1683** prior memory allocation to be at least N bytes, where N is the 1684** second parameter. The memory allocation to be resized is the first 1685** parameter. If the first parameter to sqlite3_realloc() 1686** is a NULL pointer then its behavior is identical to calling 1687** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 1688** If the second parameter to sqlite3_realloc() is zero or 1689** negative then the behavior is exactly the same as calling 1690** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 1691** sqlite3_realloc() returns a pointer to a memory allocation 1692** of at least N bytes in size or NULL if sufficient memory is unavailable. 1693** If M is the size of the prior allocation, then min(N,M) bytes 1694** of the prior allocation are copied into the beginning of buffer returned 1695** by sqlite3_realloc() and the prior allocation is freed. 1696** If sqlite3_realloc() returns NULL, then the prior allocation 1697** is not freed. 1698** 1699** The memory returned by sqlite3_malloc() and sqlite3_realloc() 1700** is always aligned to at least an 8 byte boundary. {END} 1701** 1702** The default implementation of the memory allocation subsystem uses 1703** the malloc(), realloc() and free() provided by the standard C library. 1704** {H17382} However, if SQLite is compiled with the 1705** SQLITE_MEMORY_SIZE=<i>NNN</i> C preprocessor macro (where <i>NNN</i> 1706** is an integer), then SQLite create a static array of at least 1707** <i>NNN</i> bytes in size and uses that array for all of its dynamic 1708** memory allocation needs. {END} Additional memory allocator options 1709** may be added in future releases. 1710** 1711** In SQLite version 3.5.0 and 3.5.1, it was possible to define 1712** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 1713** implementation of these routines to be omitted. That capability 1714** is no longer provided. Only built-in memory allocators can be used. 1715** 1716** The Windows OS interface layer calls 1717** the system malloc() and free() directly when converting 1718** filenames between the UTF-8 encoding used by SQLite 1719** and whatever filename encoding is used by the particular Windows 1720** installation. Memory allocation errors are detected, but 1721** they are reported back as [SQLITE_CANTOPEN] or 1722** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 1723** 1724** Requirements: 1725** [H17303] [H17304] [H17305] [H17306] [H17310] [H17312] [H17315] [H17318] 1726** [H17321] [H17322] [H17323] 1727** 1728** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 1729** must be either NULL or else pointers obtained from a prior 1730** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 1731** not yet been released. 1732** 1733** The application must not read or write any part of 1734** a block of memory after it has been released using 1735** [sqlite3_free()] or [sqlite3_realloc()]. 1736*/ 1737void *sqlite3_malloc(int); 1738void *sqlite3_realloc(void*, int); 1739void sqlite3_free(void*); 1740 1741/* 1742** CAPI3REF: Memory Allocator Statistics {H17370} <S30210> 1743** 1744** SQLite provides these two interfaces for reporting on the status 1745** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 1746** routines, which form the built-in memory allocation subsystem. 1747** 1748** Requirements: 1749** [H17371] [H17373] [H17374] [H17375] 1750*/ 1751sqlite3_int64 sqlite3_memory_used(void); 1752sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 1753 1754/* 1755** CAPI3REF: Pseudo-Random Number Generator {H17390} <S20000> 1756** 1757** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 1758** select random [ROWID | ROWIDs] when inserting new records into a table that 1759** already uses the largest possible [ROWID]. The PRNG is also used for 1760** the build-in random() and randomblob() SQL functions. This interface allows 1761** applications to access the same PRNG for other purposes. 1762** 1763** A call to this routine stores N bytes of randomness into buffer P. 1764** 1765** The first time this routine is invoked (either internally or by 1766** the application) the PRNG is seeded using randomness obtained 1767** from the xRandomness method of the default [sqlite3_vfs] object. 1768** On all subsequent invocations, the pseudo-randomness is generated 1769** internally and without recourse to the [sqlite3_vfs] xRandomness 1770** method. 1771** 1772** Requirements: 1773** [H17392] 1774*/ 1775void sqlite3_randomness(int N, void *P); 1776 1777/* 1778** CAPI3REF: Compile-Time Authorization Callbacks {H12500} <S70100> 1779** 1780** This routine registers a authorizer callback with a particular 1781** [database connection], supplied in the first argument. 1782** The authorizer callback is invoked as SQL statements are being compiled 1783** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 1784** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. At various 1785** points during the compilation process, as logic is being created 1786** to perform various actions, the authorizer callback is invoked to 1787** see if those actions are allowed. The authorizer callback should 1788** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 1789** specific action but allow the SQL statement to continue to be 1790** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 1791** rejected with an error. If the authorizer callback returns 1792** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 1793** then the [sqlite3_prepare_v2()] or equivalent call that triggered 1794** the authorizer will fail with an error message. 1795** 1796** When the callback returns [SQLITE_OK], that means the operation 1797** requested is ok. When the callback returns [SQLITE_DENY], the 1798** [sqlite3_prepare_v2()] or equivalent call that triggered the 1799** authorizer will fail with an error message explaining that 1800** access is denied. 1801** 1802** The first parameter to the authorizer callback is a copy of the third 1803** parameter to the sqlite3_set_authorizer() interface. The second parameter 1804** to the callback is an integer [SQLITE_COPY | action code] that specifies 1805** the particular action to be authorized. The third through sixth parameters 1806** to the callback are zero-terminated strings that contain additional 1807** details about the action to be authorized. 1808** 1809** If the action code is [SQLITE_READ] 1810** and the callback returns [SQLITE_IGNORE] then the 1811** [prepared statement] statement is constructed to substitute 1812** a NULL value in place of the table column that would have 1813** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 1814** return can be used to deny an untrusted user access to individual 1815** columns of a table. 1816** If the action code is [SQLITE_DELETE] and the callback returns 1817** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 1818** [truncate optimization] is disabled and all rows are deleted individually. 1819** 1820** An authorizer is used when [sqlite3_prepare | preparing] 1821** SQL statements from an untrusted source, to ensure that the SQL statements 1822** do not try to access data they are not allowed to see, or that they do not 1823** try to execute malicious statements that damage the database. For 1824** example, an application may allow a user to enter arbitrary 1825** SQL queries for evaluation by a database. But the application does 1826** not want the user to be able to make arbitrary changes to the 1827** database. An authorizer could then be put in place while the 1828** user-entered SQL is being [sqlite3_prepare | prepared] that 1829** disallows everything except [SELECT] statements. 1830** 1831** Applications that need to process SQL from untrusted sources 1832** might also consider lowering resource limits using [sqlite3_limit()] 1833** and limiting database size using the [max_page_count] [PRAGMA] 1834** in addition to using an authorizer. 1835** 1836** Only a single authorizer can be in place on a database connection 1837** at a time. Each call to sqlite3_set_authorizer overrides the 1838** previous call. Disable the authorizer by installing a NULL callback. 1839** The authorizer is disabled by default. 1840** 1841** The authorizer callback must not do anything that will modify 1842** the database connection that invoked the authorizer callback. 1843** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 1844** database connections for the meaning of "modify" in this paragraph. 1845** 1846** When [sqlite3_prepare_v2()] is used to prepare a statement, the 1847** statement might be reprepared during [sqlite3_step()] due to a 1848** schema change. Hence, the application should ensure that the 1849** correct authorizer callback remains in place during the [sqlite3_step()]. 1850** 1851** Note that the authorizer callback is invoked only during 1852** [sqlite3_prepare()] or its variants. Authorization is not 1853** performed during statement evaluation in [sqlite3_step()], unless 1854** as stated in the previous paragraph, sqlite3_step() invokes 1855** sqlite3_prepare_v2() to reprepare a statement after a schema change. 1856** 1857** Requirements: 1858** [H12501] [H12502] [H12503] [H12504] [H12505] [H12506] [H12507] [H12510] 1859** [H12511] [H12512] [H12520] [H12521] [H12522] 1860*/ 1861int sqlite3_set_authorizer( 1862 sqlite3*, 1863 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 1864 void *pUserData 1865); 1866 1867/* 1868** CAPI3REF: Authorizer Return Codes {H12590} <H12500> 1869** 1870** The [sqlite3_set_authorizer | authorizer callback function] must 1871** return either [SQLITE_OK] or one of these two constants in order 1872** to signal SQLite whether or not the action is permitted. See the 1873** [sqlite3_set_authorizer | authorizer documentation] for additional 1874** information. 1875*/ 1876#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 1877#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 1878 1879/* 1880** CAPI3REF: Authorizer Action Codes {H12550} <H12500> 1881** 1882** The [sqlite3_set_authorizer()] interface registers a callback function 1883** that is invoked to authorize certain SQL statement actions. The 1884** second parameter to the callback is an integer code that specifies 1885** what action is being authorized. These are the integer action codes that 1886** the authorizer callback may be passed. 1887** 1888** These action code values signify what kind of operation is to be 1889** authorized. The 3rd and 4th parameters to the authorization 1890** callback function will be parameters or NULL depending on which of these 1891** codes is used as the second parameter. The 5th parameter to the 1892** authorizer callback is the name of the database ("main", "temp", 1893** etc.) if applicable. The 6th parameter to the authorizer callback 1894** is the name of the inner-most trigger or view that is responsible for 1895** the access attempt or NULL if this access attempt is directly from 1896** top-level SQL code. 1897** 1898** Requirements: 1899** [H12551] [H12552] [H12553] [H12554] 1900*/ 1901/******************************************* 3rd ************ 4th ***********/ 1902#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 1903#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 1904#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 1905#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 1906#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 1907#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 1908#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 1909#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 1910#define SQLITE_DELETE 9 /* Table Name NULL */ 1911#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 1912#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 1913#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 1914#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 1915#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 1916#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 1917#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 1918#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 1919#define SQLITE_INSERT 18 /* Table Name NULL */ 1920#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 1921#define SQLITE_READ 20 /* Table Name Column Name */ 1922#define SQLITE_SELECT 21 /* NULL NULL */ 1923#define SQLITE_TRANSACTION 22 /* Operation NULL */ 1924#define SQLITE_UPDATE 23 /* Table Name Column Name */ 1925#define SQLITE_ATTACH 24 /* Filename NULL */ 1926#define SQLITE_DETACH 25 /* Database Name NULL */ 1927#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 1928#define SQLITE_REINDEX 27 /* Index Name NULL */ 1929#define SQLITE_ANALYZE 28 /* Table Name NULL */ 1930#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 1931#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 1932#define SQLITE_FUNCTION 31 /* NULL Function Name */ 1933#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 1934#define SQLITE_COPY 0 /* No longer used */ 1935 1936/* 1937** CAPI3REF: Tracing And Profiling Functions {H12280} <S60400> 1938** EXPERIMENTAL 1939** 1940** These routines register callback functions that can be used for 1941** tracing and profiling the execution of SQL statements. 1942** 1943** The callback function registered by sqlite3_trace() is invoked at 1944** various times when an SQL statement is being run by [sqlite3_step()]. 1945** The callback returns a UTF-8 rendering of the SQL statement text 1946** as the statement first begins executing. Additional callbacks occur 1947** as each triggered subprogram is entered. The callbacks for triggers 1948** contain a UTF-8 SQL comment that identifies the trigger. 1949** 1950** The callback function registered by sqlite3_profile() is invoked 1951** as each SQL statement finishes. The profile callback contains 1952** the original statement text and an estimate of wall-clock time 1953** of how long that statement took to run. 1954** 1955** Requirements: 1956** [H12281] [H12282] [H12283] [H12284] [H12285] [H12287] [H12288] [H12289] 1957** [H12290] 1958*/ 1959SQLITE_EXPERIMENTAL void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 1960SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 1961 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 1962 1963/* 1964** CAPI3REF: Query Progress Callbacks {H12910} <S60400> 1965** 1966** This routine configures a callback function - the 1967** progress callback - that is invoked periodically during long 1968** running calls to [sqlite3_exec()], [sqlite3_step()] and 1969** [sqlite3_get_table()]. An example use for this 1970** interface is to keep a GUI updated during a large query. 1971** 1972** If the progress callback returns non-zero, the operation is 1973** interrupted. This feature can be used to implement a 1974** "Cancel" button on a GUI progress dialog box. 1975** 1976** The progress handler must not do anything that will modify 1977** the database connection that invoked the progress handler. 1978** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 1979** database connections for the meaning of "modify" in this paragraph. 1980** 1981** Requirements: 1982** [H12911] [H12912] [H12913] [H12914] [H12915] [H12916] [H12917] [H12918] 1983** 1984*/ 1985void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 1986 1987/* 1988** CAPI3REF: Opening A New Database Connection {H12700} <S40200> 1989** 1990** These routines open an SQLite database file whose name is given by the 1991** filename argument. The filename argument is interpreted as UTF-8 for 1992** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 1993** order for sqlite3_open16(). A [database connection] handle is usually 1994** returned in *ppDb, even if an error occurs. The only exception is that 1995** if SQLite is unable to allocate memory to hold the [sqlite3] object, 1996** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 1997** object. If the database is opened (and/or created) successfully, then 1998** [SQLITE_OK] is returned. Otherwise an [error code] is returned. The 1999** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2000** an English language description of the error. 2001** 2002** The default encoding for the database will be UTF-8 if 2003** sqlite3_open() or sqlite3_open_v2() is called and 2004** UTF-16 in the native byte order if sqlite3_open16() is used. 2005** 2006** Whether or not an error occurs when it is opened, resources 2007** associated with the [database connection] handle should be released by 2008** passing it to [sqlite3_close()] when it is no longer required. 2009** 2010** The sqlite3_open_v2() interface works like sqlite3_open() 2011** except that it accepts two additional parameters for additional control 2012** over the new database connection. The flags parameter can take one of 2013** the following three values, optionally combined with the 2014** [SQLITE_OPEN_NOMUTEX] or [SQLITE_OPEN_FULLMUTEX] flags: 2015** 2016** <dl> 2017** <dt>[SQLITE_OPEN_READONLY]</dt> 2018** <dd>The database is opened in read-only mode. If the database does not 2019** already exist, an error is returned.</dd> 2020** 2021** <dt>[SQLITE_OPEN_READWRITE]</dt> 2022** <dd>The database is opened for reading and writing if possible, or reading 2023** only if the file is write protected by the operating system. In either 2024** case the database must already exist, otherwise an error is returned.</dd> 2025** 2026** <dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2027** <dd>The database is opened for reading and writing, and is creates it if 2028** it does not already exist. This is the behavior that is always used for 2029** sqlite3_open() and sqlite3_open16().</dd> 2030** </dl> 2031** 2032** If the 3rd parameter to sqlite3_open_v2() is not one of the 2033** combinations shown above or one of the combinations shown above combined 2034** with the [SQLITE_OPEN_NOMUTEX] or [SQLITE_OPEN_FULLMUTEX] flags, 2035** then the behavior is undefined. 2036** 2037** If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2038** opens in the multi-thread [threading mode] as long as the single-thread 2039** mode has not been set at compile-time or start-time. If the 2040** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2041** in the serialized [threading mode] unless single-thread was 2042** previously selected at compile-time or start-time. 2043** 2044** If the filename is ":memory:", then a private, temporary in-memory database 2045** is created for the connection. This in-memory database will vanish when 2046** the database connection is closed. Future versions of SQLite might 2047** make use of additional special filenames that begin with the ":" character. 2048** It is recommended that when a database filename actually does begin with 2049** a ":" character you should prefix the filename with a pathname such as 2050** "./" to avoid ambiguity. 2051** 2052** If the filename is an empty string, then a private, temporary 2053** on-disk database will be created. This private database will be 2054** automatically deleted as soon as the database connection is closed. 2055** 2056** The fourth parameter to sqlite3_open_v2() is the name of the 2057** [sqlite3_vfs] object that defines the operating system interface that 2058** the new database connection should use. If the fourth parameter is 2059** a NULL pointer then the default [sqlite3_vfs] object is used. 2060** 2061** <b>Note to Windows users:</b> The encoding used for the filename argument 2062** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2063** codepage is currently defined. Filenames containing international 2064** characters must be converted to UTF-8 prior to passing them into 2065** sqlite3_open() or sqlite3_open_v2(). 2066** 2067** Requirements: 2068** [H12701] [H12702] [H12703] [H12704] [H12706] [H12707] [H12709] [H12711] 2069** [H12712] [H12713] [H12714] [H12717] [H12719] [H12721] [H12723] 2070*/ 2071int sqlite3_open( 2072 const char *filename, /* Database filename (UTF-8) */ 2073 sqlite3 **ppDb /* OUT: SQLite db handle */ 2074); 2075int sqlite3_open16( 2076 const void *filename, /* Database filename (UTF-16) */ 2077 sqlite3 **ppDb /* OUT: SQLite db handle */ 2078); 2079int sqlite3_open_v2( 2080 const char *filename, /* Database filename (UTF-8) */ 2081 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2082 int flags, /* Flags */ 2083 const char *zVfs /* Name of VFS module to use */ 2084); 2085 2086/* 2087** CAPI3REF: Error Codes And Messages {H12800} <S60200> 2088** 2089** The sqlite3_errcode() interface returns the numeric [result code] or 2090** [extended result code] for the most recent failed sqlite3_* API call 2091** associated with a [database connection]. If a prior API call failed 2092** but the most recent API call succeeded, the return value from 2093** sqlite3_errcode() is undefined. The sqlite3_extended_errcode() 2094** interface is the same except that it always returns the 2095** [extended result code] even when extended result codes are 2096** disabled. 2097** 2098** The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2099** text that describes the error, as either UTF-8 or UTF-16 respectively. 2100** Memory to hold the error message string is managed internally. 2101** The application does not need to worry about freeing the result. 2102** However, the error string might be overwritten or deallocated by 2103** subsequent calls to other SQLite interface functions. 2104** 2105** When the serialized [threading mode] is in use, it might be the 2106** case that a second error occurs on a separate thread in between 2107** the time of the first error and the call to these interfaces. 2108** When that happens, the second error will be reported since these 2109** interfaces always report the most recent result. To avoid 2110** this, each thread can obtain exclusive use of the [database connection] D 2111** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2112** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2113** all calls to the interfaces listed here are completed. 2114** 2115** If an interface fails with SQLITE_MISUSE, that means the interface 2116** was invoked incorrectly by the application. In that case, the 2117** error code and message may or may not be set. 2118** 2119** Requirements: 2120** [H12801] [H12802] [H12803] [H12807] [H12808] [H12809] 2121*/ 2122int sqlite3_errcode(sqlite3 *db); 2123int sqlite3_extended_errcode(sqlite3 *db); 2124const char *sqlite3_errmsg(sqlite3*); 2125const void *sqlite3_errmsg16(sqlite3*); 2126 2127/* 2128** CAPI3REF: SQL Statement Object {H13000} <H13010> 2129** KEYWORDS: {prepared statement} {prepared statements} 2130** 2131** An instance of this object represents a single SQL statement. 2132** This object is variously known as a "prepared statement" or a 2133** "compiled SQL statement" or simply as a "statement". 2134** 2135** The life of a statement object goes something like this: 2136** 2137** <ol> 2138** <li> Create the object using [sqlite3_prepare_v2()] or a related 2139** function. 2140** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2141** interfaces. 2142** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2143** <li> Reset the statement using [sqlite3_reset()] then go back 2144** to step 2. Do this zero or more times. 2145** <li> Destroy the object using [sqlite3_finalize()]. 2146** </ol> 2147** 2148** Refer to documentation on individual methods above for additional 2149** information. 2150*/ 2151typedef struct sqlite3_stmt sqlite3_stmt; 2152 2153/* 2154** CAPI3REF: Run-time Limits {H12760} <S20600> 2155** 2156** This interface allows the size of various constructs to be limited 2157** on a connection by connection basis. The first parameter is the 2158** [database connection] whose limit is to be set or queried. The 2159** second parameter is one of the [limit categories] that define a 2160** class of constructs to be size limited. The third parameter is the 2161** new limit for that construct. The function returns the old limit. 2162** 2163** If the new limit is a negative number, the limit is unchanged. 2164** For the limit category of SQLITE_LIMIT_XYZ there is a 2165** [limits | hard upper bound] 2166** set by a compile-time C preprocessor macro named 2167** [limits | SQLITE_MAX_XYZ]. 2168** (The "_LIMIT_" in the name is changed to "_MAX_".) 2169** Attempts to increase a limit above its hard upper bound are 2170** silently truncated to the hard upper limit. 2171** 2172** Run time limits are intended for use in applications that manage 2173** both their own internal database and also databases that are controlled 2174** by untrusted external sources. An example application might be a 2175** web browser that has its own databases for storing history and 2176** separate databases controlled by JavaScript applications downloaded 2177** off the Internet. The internal databases can be given the 2178** large, default limits. Databases managed by external sources can 2179** be given much smaller limits designed to prevent a denial of service 2180** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2181** interface to further control untrusted SQL. The size of the database 2182** created by an untrusted script can be contained using the 2183** [max_page_count] [PRAGMA]. 2184** 2185** New run-time limit categories may be added in future releases. 2186** 2187** Requirements: 2188** [H12762] [H12766] [H12769] 2189*/ 2190int sqlite3_limit(sqlite3*, int id, int newVal); 2191 2192/* 2193** CAPI3REF: Run-Time Limit Categories {H12790} <H12760> 2194** KEYWORDS: {limit category} {limit categories} 2195** 2196** These constants define various performance limits 2197** that can be lowered at run-time using [sqlite3_limit()]. 2198** The synopsis of the meanings of the various limits is shown below. 2199** Additional information is available at [limits | Limits in SQLite]. 2200** 2201** <dl> 2202** <dt>SQLITE_LIMIT_LENGTH</dt> 2203** <dd>The maximum size of any string or BLOB or table row.<dd> 2204** 2205** <dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2206** <dd>The maximum length of an SQL statement.</dd> 2207** 2208** <dt>SQLITE_LIMIT_COLUMN</dt> 2209** <dd>The maximum number of columns in a table definition or in the 2210** result set of a [SELECT] or the maximum number of columns in an index 2211** or in an ORDER BY or GROUP BY clause.</dd> 2212** 2213** <dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2214** <dd>The maximum depth of the parse tree on any expression.</dd> 2215** 2216** <dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2217** <dd>The maximum number of terms in a compound SELECT statement.</dd> 2218** 2219** <dt>SQLITE_LIMIT_VDBE_OP</dt> 2220** <dd>The maximum number of instructions in a virtual machine program 2221** used to implement an SQL statement.</dd> 2222** 2223** <dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2224** <dd>The maximum number of arguments on a function.</dd> 2225** 2226** <dt>SQLITE_LIMIT_ATTACHED</dt> 2227** <dd>The maximum number of [ATTACH | attached databases].</dd> 2228** 2229** <dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2230** <dd>The maximum length of the pattern argument to the [LIKE] or 2231** [GLOB] operators.</dd> 2232** 2233** <dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2234** <dd>The maximum number of variables in an SQL statement that can 2235** be bound.</dd> 2236** </dl> 2237*/ 2238#define SQLITE_LIMIT_LENGTH 0 2239#define SQLITE_LIMIT_SQL_LENGTH 1 2240#define SQLITE_LIMIT_COLUMN 2 2241#define SQLITE_LIMIT_EXPR_DEPTH 3 2242#define SQLITE_LIMIT_COMPOUND_SELECT 4 2243#define SQLITE_LIMIT_VDBE_OP 5 2244#define SQLITE_LIMIT_FUNCTION_ARG 6 2245#define SQLITE_LIMIT_ATTACHED 7 2246#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2247#define SQLITE_LIMIT_VARIABLE_NUMBER 9 2248 2249/* 2250** CAPI3REF: Compiling An SQL Statement {H13010} <S10000> 2251** KEYWORDS: {SQL statement compiler} 2252** 2253** To execute an SQL query, it must first be compiled into a byte-code 2254** program using one of these routines. 2255** 2256** The first argument, "db", is a [database connection] obtained from a 2257** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2258** [sqlite3_open16()]. The database connection must not have been closed. 2259** 2260** The second argument, "zSql", is the statement to be compiled, encoded 2261** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2262** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2263** use UTF-16. 2264** 2265** If the nByte argument is less than zero, then zSql is read up to the 2266** first zero terminator. If nByte is non-negative, then it is the maximum 2267** number of bytes read from zSql. When nByte is non-negative, the 2268** zSql string ends at either the first '\000' or '\u0000' character or 2269** the nByte-th byte, whichever comes first. If the caller knows 2270** that the supplied string is nul-terminated, then there is a small 2271** performance advantage to be gained by passing an nByte parameter that 2272** is equal to the number of bytes in the input string <i>including</i> 2273** the nul-terminator bytes. 2274** 2275** If pzTail is not NULL then *pzTail is made to point to the first byte 2276** past the end of the first SQL statement in zSql. These routines only 2277** compile the first statement in zSql, so *pzTail is left pointing to 2278** what remains uncompiled. 2279** 2280** *ppStmt is left pointing to a compiled [prepared statement] that can be 2281** executed using [sqlite3_step()]. If there is an error, *ppStmt is set 2282** to NULL. If the input text contains no SQL (if the input is an empty 2283** string or a comment) then *ppStmt is set to NULL. 2284** The calling procedure is responsible for deleting the compiled 2285** SQL statement using [sqlite3_finalize()] after it has finished with it. 2286** ppStmt may not be NULL. 2287** 2288** On success, [SQLITE_OK] is returned, otherwise an [error code] is returned. 2289** 2290** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2291** recommended for all new programs. The two older interfaces are retained 2292** for backwards compatibility, but their use is discouraged. 2293** In the "v2" interfaces, the prepared statement 2294** that is returned (the [sqlite3_stmt] object) contains a copy of the 2295** original SQL text. This causes the [sqlite3_step()] interface to 2296** behave a differently in two ways: 2297** 2298** <ol> 2299** <li> 2300** If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2301** always used to do, [sqlite3_step()] will automatically recompile the SQL 2302** statement and try to run it again. If the schema has changed in 2303** a way that makes the statement no longer valid, [sqlite3_step()] will still 2304** return [SQLITE_SCHEMA]. But unlike the legacy behavior, [SQLITE_SCHEMA] is 2305** now a fatal error. Calling [sqlite3_prepare_v2()] again will not make the 2306** error go away. Note: use [sqlite3_errmsg()] to find the text 2307** of the parsing error that results in an [SQLITE_SCHEMA] return. 2308** </li> 2309** 2310** <li> 2311** When an error occurs, [sqlite3_step()] will return one of the detailed 2312** [error codes] or [extended error codes]. The legacy behavior was that 2313** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2314** and you would have to make a second call to [sqlite3_reset()] in order 2315** to find the underlying cause of the problem. With the "v2" prepare 2316** interfaces, the underlying reason for the error is returned immediately. 2317** </li> 2318** </ol> 2319** 2320** Requirements: 2321** [H13011] [H13012] [H13013] [H13014] [H13015] [H13016] [H13019] [H13021] 2322** 2323*/ 2324int sqlite3_prepare( 2325 sqlite3 *db, /* Database handle */ 2326 const char *zSql, /* SQL statement, UTF-8 encoded */ 2327 int nByte, /* Maximum length of zSql in bytes. */ 2328 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2329 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2330); 2331int sqlite3_prepare_v2( 2332 sqlite3 *db, /* Database handle */ 2333 const char *zSql, /* SQL statement, UTF-8 encoded */ 2334 int nByte, /* Maximum length of zSql in bytes. */ 2335 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2336 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2337); 2338int sqlite3_prepare16( 2339 sqlite3 *db, /* Database handle */ 2340 const void *zSql, /* SQL statement, UTF-16 encoded */ 2341 int nByte, /* Maximum length of zSql in bytes. */ 2342 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2343 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2344); 2345int sqlite3_prepare16_v2( 2346 sqlite3 *db, /* Database handle */ 2347 const void *zSql, /* SQL statement, UTF-16 encoded */ 2348 int nByte, /* Maximum length of zSql in bytes. */ 2349 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2350 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2351); 2352 2353/* 2354** CAPI3REF: Retrieving Statement SQL {H13100} <H13000> 2355** 2356** This interface can be used to retrieve a saved copy of the original 2357** SQL text used to create a [prepared statement] if that statement was 2358** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2359** 2360** Requirements: 2361** [H13101] [H13102] [H13103] 2362*/ 2363const char *sqlite3_sql(sqlite3_stmt *pStmt); 2364 2365/* 2366** CAPI3REF: Dynamically Typed Value Object {H15000} <S20200> 2367** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 2368** 2369** SQLite uses the sqlite3_value object to represent all values 2370** that can be stored in a database table. SQLite uses dynamic typing 2371** for the values it stores. Values stored in sqlite3_value objects 2372** can be integers, floating point values, strings, BLOBs, or NULL. 2373** 2374** An sqlite3_value object may be either "protected" or "unprotected". 2375** Some interfaces require a protected sqlite3_value. Other interfaces 2376** will accept either a protected or an unprotected sqlite3_value. 2377** Every interface that accepts sqlite3_value arguments specifies 2378** whether or not it requires a protected sqlite3_value. 2379** 2380** The terms "protected" and "unprotected" refer to whether or not 2381** a mutex is held. A internal mutex is held for a protected 2382** sqlite3_value object but no mutex is held for an unprotected 2383** sqlite3_value object. If SQLite is compiled to be single-threaded 2384** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 2385** or if SQLite is run in one of reduced mutex modes 2386** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 2387** then there is no distinction between protected and unprotected 2388** sqlite3_value objects and they can be used interchangeably. However, 2389** for maximum code portability it is recommended that applications 2390** still make the distinction between between protected and unprotected 2391** sqlite3_value objects even when not strictly required. 2392** 2393** The sqlite3_value objects that are passed as parameters into the 2394** implementation of [application-defined SQL functions] are protected. 2395** The sqlite3_value object returned by 2396** [sqlite3_column_value()] is unprotected. 2397** Unprotected sqlite3_value objects may only be used with 2398** [sqlite3_result_value()] and [sqlite3_bind_value()]. 2399** The [sqlite3_value_blob | sqlite3_value_type()] family of 2400** interfaces require protected sqlite3_value objects. 2401*/ 2402typedef struct Mem sqlite3_value; 2403 2404/* 2405** CAPI3REF: SQL Function Context Object {H16001} <S20200> 2406** 2407** The context in which an SQL function executes is stored in an 2408** sqlite3_context object. A pointer to an sqlite3_context object 2409** is always first parameter to [application-defined SQL functions]. 2410** The application-defined SQL function implementation will pass this 2411** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 2412** [sqlite3_aggregate_context()], [sqlite3_user_data()], 2413** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 2414** and/or [sqlite3_set_auxdata()]. 2415*/ 2416typedef struct sqlite3_context sqlite3_context; 2417 2418/* 2419** CAPI3REF: Binding Values To Prepared Statements {H13500} <S70300> 2420** KEYWORDS: {host parameter} {host parameters} {host parameter name} 2421** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 2422** 2423** In the SQL strings input to [sqlite3_prepare_v2()] and its variants, 2424** literals may be replaced by a [parameter] in one of these forms: 2425** 2426** <ul> 2427** <li> ? 2428** <li> ?NNN 2429** <li> :VVV 2430** <li> @VVV 2431** <li> $VVV 2432** </ul> 2433** 2434** In the parameter forms shown above NNN is an integer literal, 2435** and VVV is an alpha-numeric parameter name. The values of these 2436** parameters (also called "host parameter names" or "SQL parameters") 2437** can be set using the sqlite3_bind_*() routines defined here. 2438** 2439** The first argument to the sqlite3_bind_*() routines is always 2440** a pointer to the [sqlite3_stmt] object returned from 2441** [sqlite3_prepare_v2()] or its variants. 2442** 2443** The second argument is the index of the SQL parameter to be set. 2444** The leftmost SQL parameter has an index of 1. When the same named 2445** SQL parameter is used more than once, second and subsequent 2446** occurrences have the same index as the first occurrence. 2447** The index for named parameters can be looked up using the 2448** [sqlite3_bind_parameter_index()] API if desired. The index 2449** for "?NNN" parameters is the value of NNN. 2450** The NNN value must be between 1 and the [sqlite3_limit()] 2451** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 2452** 2453** The third argument is the value to bind to the parameter. 2454** 2455** In those routines that have a fourth argument, its value is the 2456** number of bytes in the parameter. To be clear: the value is the 2457** number of <u>bytes</u> in the value, not the number of characters. 2458** If the fourth parameter is negative, the length of the string is 2459** the number of bytes up to the first zero terminator. 2460** 2461** The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 2462** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 2463** string after SQLite has finished with it. If the fifth argument is 2464** the special value [SQLITE_STATIC], then SQLite assumes that the 2465** information is in static, unmanaged space and does not need to be freed. 2466** If the fifth argument has the value [SQLITE_TRANSIENT], then 2467** SQLite makes its own private copy of the data immediately, before 2468** the sqlite3_bind_*() routine returns. 2469** 2470** The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 2471** is filled with zeroes. A zeroblob uses a fixed amount of memory 2472** (just an integer to hold its size) while it is being processed. 2473** Zeroblobs are intended to serve as placeholders for BLOBs whose 2474** content is later written using 2475** [sqlite3_blob_open | incremental BLOB I/O] routines. 2476** A negative value for the zeroblob results in a zero-length BLOB. 2477** 2478** The sqlite3_bind_*() routines must be called after 2479** [sqlite3_prepare_v2()] (and its variants) or [sqlite3_reset()] and 2480** before [sqlite3_step()]. 2481** Bindings are not cleared by the [sqlite3_reset()] routine. 2482** Unbound parameters are interpreted as NULL. 2483** 2484** These routines return [SQLITE_OK] on success or an error code if 2485** anything goes wrong. [SQLITE_RANGE] is returned if the parameter 2486** index is out of range. [SQLITE_NOMEM] is returned if malloc() fails. 2487** [SQLITE_MISUSE] might be returned if these routines are called on a 2488** virtual machine that is the wrong state or which has already been finalized. 2489** Detection of misuse is unreliable. Applications should not depend 2490** on SQLITE_MISUSE returns. SQLITE_MISUSE is intended to indicate a 2491** a logic error in the application. Future versions of SQLite might 2492** panic rather than return SQLITE_MISUSE. 2493** 2494** See also: [sqlite3_bind_parameter_count()], 2495** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 2496** 2497** Requirements: 2498** [H13506] [H13509] [H13512] [H13515] [H13518] [H13521] [H13524] [H13527] 2499** [H13530] [H13533] [H13536] [H13539] [H13542] [H13545] [H13548] [H13551] 2500** 2501*/ 2502int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 2503int sqlite3_bind_double(sqlite3_stmt*, int, double); 2504int sqlite3_bind_int(sqlite3_stmt*, int, int); 2505int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 2506int sqlite3_bind_null(sqlite3_stmt*, int); 2507int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 2508int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 2509int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 2510int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 2511 2512/* 2513** CAPI3REF: Number Of SQL Parameters {H13600} <S70300> 2514** 2515** This routine can be used to find the number of [SQL parameters] 2516** in a [prepared statement]. SQL parameters are tokens of the 2517** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 2518** placeholders for values that are [sqlite3_bind_blob | bound] 2519** to the parameters at a later time. 2520** 2521** This routine actually returns the index of the largest (rightmost) 2522** parameter. For all forms except ?NNN, this will correspond to the 2523** number of unique parameters. If parameters of the ?NNN are used, 2524** there may be gaps in the list. 2525** 2526** See also: [sqlite3_bind_blob|sqlite3_bind()], 2527** [sqlite3_bind_parameter_name()], and 2528** [sqlite3_bind_parameter_index()]. 2529** 2530** Requirements: 2531** [H13601] 2532*/ 2533int sqlite3_bind_parameter_count(sqlite3_stmt*); 2534 2535/* 2536** CAPI3REF: Name Of A Host Parameter {H13620} <S70300> 2537** 2538** This routine returns a pointer to the name of the n-th 2539** [SQL parameter] in a [prepared statement]. 2540** SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 2541** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 2542** respectively. 2543** In other words, the initial ":" or "$" or "@" or "?" 2544** is included as part of the name. 2545** Parameters of the form "?" without a following integer have no name 2546** and are also referred to as "anonymous parameters". 2547** 2548** The first host parameter has an index of 1, not 0. 2549** 2550** If the value n is out of range or if the n-th parameter is 2551** nameless, then NULL is returned. The returned string is 2552** always in UTF-8 encoding even if the named parameter was 2553** originally specified as UTF-16 in [sqlite3_prepare16()] or 2554** [sqlite3_prepare16_v2()]. 2555** 2556** See also: [sqlite3_bind_blob|sqlite3_bind()], 2557** [sqlite3_bind_parameter_count()], and 2558** [sqlite3_bind_parameter_index()]. 2559** 2560** Requirements: 2561** [H13621] 2562*/ 2563const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 2564 2565/* 2566** CAPI3REF: Index Of A Parameter With A Given Name {H13640} <S70300> 2567** 2568** Return the index of an SQL parameter given its name. The 2569** index value returned is suitable for use as the second 2570** parameter to [sqlite3_bind_blob|sqlite3_bind()]. A zero 2571** is returned if no matching parameter is found. The parameter 2572** name must be given in UTF-8 even if the original statement 2573** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 2574** 2575** See also: [sqlite3_bind_blob|sqlite3_bind()], 2576** [sqlite3_bind_parameter_count()], and 2577** [sqlite3_bind_parameter_index()]. 2578** 2579** Requirements: 2580** [H13641] 2581*/ 2582int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 2583 2584/* 2585** CAPI3REF: Reset All Bindings On A Prepared Statement {H13660} <S70300> 2586** 2587** Contrary to the intuition of many, [sqlite3_reset()] does not reset 2588** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 2589** Use this routine to reset all host parameters to NULL. 2590** 2591** Requirements: 2592** [H13661] 2593*/ 2594int sqlite3_clear_bindings(sqlite3_stmt*); 2595 2596/* 2597** CAPI3REF: Number Of Columns In A Result Set {H13710} <S10700> 2598** 2599** Return the number of columns in the result set returned by the 2600** [prepared statement]. This routine returns 0 if pStmt is an SQL 2601** statement that does not return data (for example an [UPDATE]). 2602** 2603** Requirements: 2604** [H13711] 2605*/ 2606int sqlite3_column_count(sqlite3_stmt *pStmt); 2607 2608/* 2609** CAPI3REF: Column Names In A Result Set {H13720} <S10700> 2610** 2611** These routines return the name assigned to a particular column 2612** in the result set of a [SELECT] statement. The sqlite3_column_name() 2613** interface returns a pointer to a zero-terminated UTF-8 string 2614** and sqlite3_column_name16() returns a pointer to a zero-terminated 2615** UTF-16 string. The first parameter is the [prepared statement] 2616** that implements the [SELECT] statement. The second parameter is the 2617** column number. The leftmost column is number 0. 2618** 2619** The returned string pointer is valid until either the [prepared statement] 2620** is destroyed by [sqlite3_finalize()] or until the next call to 2621** sqlite3_column_name() or sqlite3_column_name16() on the same column. 2622** 2623** If sqlite3_malloc() fails during the processing of either routine 2624** (for example during a conversion from UTF-8 to UTF-16) then a 2625** NULL pointer is returned. 2626** 2627** The name of a result column is the value of the "AS" clause for 2628** that column, if there is an AS clause. If there is no AS clause 2629** then the name of the column is unspecified and may change from 2630** one release of SQLite to the next. 2631** 2632** Requirements: 2633** [H13721] [H13723] [H13724] [H13725] [H13726] [H13727] 2634*/ 2635const char *sqlite3_column_name(sqlite3_stmt*, int N); 2636const void *sqlite3_column_name16(sqlite3_stmt*, int N); 2637 2638/* 2639** CAPI3REF: Source Of Data In A Query Result {H13740} <S10700> 2640** 2641** These routines provide a means to determine what column of what 2642** table in which database a result of a [SELECT] statement comes from. 2643** The name of the database or table or column can be returned as 2644** either a UTF-8 or UTF-16 string. The _database_ routines return 2645** the database name, the _table_ routines return the table name, and 2646** the origin_ routines return the column name. 2647** The returned string is valid until the [prepared statement] is destroyed 2648** using [sqlite3_finalize()] or until the same information is requested 2649** again in a different encoding. 2650** 2651** The names returned are the original un-aliased names of the 2652** database, table, and column. 2653** 2654** The first argument to the following calls is a [prepared statement]. 2655** These functions return information about the Nth column returned by 2656** the statement, where N is the second function argument. 2657** 2658** If the Nth column returned by the statement is an expression or 2659** subquery and is not a column value, then all of these functions return 2660** NULL. These routine might also return NULL if a memory allocation error 2661** occurs. Otherwise, they return the name of the attached database, table 2662** and column that query result column was extracted from. 2663** 2664** As with all other SQLite APIs, those postfixed with "16" return 2665** UTF-16 encoded strings, the other functions return UTF-8. {END} 2666** 2667** These APIs are only available if the library was compiled with the 2668** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 2669** 2670** {A13751} 2671** If two or more threads call one or more of these routines against the same 2672** prepared statement and column at the same time then the results are 2673** undefined. 2674** 2675** Requirements: 2676** [H13741] [H13742] [H13743] [H13744] [H13745] [H13746] [H13748] 2677** 2678** If two or more threads call one or more 2679** [sqlite3_column_database_name | column metadata interfaces] 2680** for the same [prepared statement] and result column 2681** at the same time then the results are undefined. 2682*/ 2683const char *sqlite3_column_database_name(sqlite3_stmt*,int); 2684const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 2685const char *sqlite3_column_table_name(sqlite3_stmt*,int); 2686const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 2687const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 2688const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 2689 2690/* 2691** CAPI3REF: Declared Datatype Of A Query Result {H13760} <S10700> 2692** 2693** The first parameter is a [prepared statement]. 2694** If this statement is a [SELECT] statement and the Nth column of the 2695** returned result set of that [SELECT] is a table column (not an 2696** expression or subquery) then the declared type of the table 2697** column is returned. If the Nth column of the result set is an 2698** expression or subquery, then a NULL pointer is returned. 2699** The returned string is always UTF-8 encoded. {END} 2700** 2701** For example, given the database schema: 2702** 2703** CREATE TABLE t1(c1 VARIANT); 2704** 2705** and the following statement to be compiled: 2706** 2707** SELECT c1 + 1, c1 FROM t1; 2708** 2709** this routine would return the string "VARIANT" for the second result 2710** column (i==1), and a NULL pointer for the first result column (i==0). 2711** 2712** SQLite uses dynamic run-time typing. So just because a column 2713** is declared to contain a particular type does not mean that the 2714** data stored in that column is of the declared type. SQLite is 2715** strongly typed, but the typing is dynamic not static. Type 2716** is associated with individual values, not with the containers 2717** used to hold those values. 2718** 2719** Requirements: 2720** [H13761] [H13762] [H13763] 2721*/ 2722const char *sqlite3_column_decltype(sqlite3_stmt*,int); 2723const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 2724 2725/* 2726** CAPI3REF: Evaluate An SQL Statement {H13200} <S10000> 2727** 2728** After a [prepared statement] has been prepared using either 2729** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 2730** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 2731** must be called one or more times to evaluate the statement. 2732** 2733** The details of the behavior of the sqlite3_step() interface depend 2734** on whether the statement was prepared using the newer "v2" interface 2735** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 2736** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 2737** new "v2" interface is recommended for new applications but the legacy 2738** interface will continue to be supported. 2739** 2740** In the legacy interface, the return value will be either [SQLITE_BUSY], 2741** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 2742** With the "v2" interface, any of the other [result codes] or 2743** [extended result codes] might be returned as well. 2744** 2745** [SQLITE_BUSY] means that the database engine was unable to acquire the 2746** database locks it needs to do its job. If the statement is a [COMMIT] 2747** or occurs outside of an explicit transaction, then you can retry the 2748** statement. If the statement is not a [COMMIT] and occurs within a 2749** explicit transaction then you should rollback the transaction before 2750** continuing. 2751** 2752** [SQLITE_DONE] means that the statement has finished executing 2753** successfully. sqlite3_step() should not be called again on this virtual 2754** machine without first calling [sqlite3_reset()] to reset the virtual 2755** machine back to its initial state. 2756** 2757** If the SQL statement being executed returns any data, then [SQLITE_ROW] 2758** is returned each time a new row of data is ready for processing by the 2759** caller. The values may be accessed using the [column access functions]. 2760** sqlite3_step() is called again to retrieve the next row of data. 2761** 2762** [SQLITE_ERROR] means that a run-time error (such as a constraint 2763** violation) has occurred. sqlite3_step() should not be called again on 2764** the VM. More information may be found by calling [sqlite3_errmsg()]. 2765** With the legacy interface, a more specific error code (for example, 2766** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 2767** can be obtained by calling [sqlite3_reset()] on the 2768** [prepared statement]. In the "v2" interface, 2769** the more specific error code is returned directly by sqlite3_step(). 2770** 2771** [SQLITE_MISUSE] means that the this routine was called inappropriately. 2772** Perhaps it was called on a [prepared statement] that has 2773** already been [sqlite3_finalize | finalized] or on one that had 2774** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 2775** be the case that the same database connection is being used by two or 2776** more threads at the same moment in time. 2777** 2778** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 2779** API always returns a generic error code, [SQLITE_ERROR], following any 2780** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 2781** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 2782** specific [error codes] that better describes the error. 2783** We admit that this is a goofy design. The problem has been fixed 2784** with the "v2" interface. If you prepare all of your SQL statements 2785** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 2786** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 2787** then the more specific [error codes] are returned directly 2788** by sqlite3_step(). The use of the "v2" interface is recommended. 2789** 2790** Requirements: 2791** [H13202] [H15304] [H15306] [H15308] [H15310] 2792*/ 2793int sqlite3_step(sqlite3_stmt*); 2794 2795/* 2796** CAPI3REF: Number of columns in a result set {H13770} <S10700> 2797** 2798** Returns the number of values in the current row of the result set. 2799** 2800** Requirements: 2801** [H13771] [H13772] 2802*/ 2803int sqlite3_data_count(sqlite3_stmt *pStmt); 2804 2805/* 2806** CAPI3REF: Fundamental Datatypes {H10265} <S10110><S10120> 2807** KEYWORDS: SQLITE_TEXT 2808** 2809** {H10266} Every value in SQLite has one of five fundamental datatypes: 2810** 2811** <ul> 2812** <li> 64-bit signed integer 2813** <li> 64-bit IEEE floating point number 2814** <li> string 2815** <li> BLOB 2816** <li> NULL 2817** </ul> {END} 2818** 2819** These constants are codes for each of those types. 2820** 2821** Note that the SQLITE_TEXT constant was also used in SQLite version 2 2822** for a completely different meaning. Software that links against both 2823** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 2824** SQLITE_TEXT. 2825*/ 2826#define SQLITE_INTEGER 1 2827#define SQLITE_FLOAT 2 2828#define SQLITE_BLOB 4 2829#define SQLITE_NULL 5 2830#ifdef SQLITE_TEXT 2831# undef SQLITE_TEXT 2832#else 2833# define SQLITE_TEXT 3 2834#endif 2835#define SQLITE3_TEXT 3 2836 2837/* 2838** CAPI3REF: Result Values From A Query {H13800} <S10700> 2839** KEYWORDS: {column access functions} 2840** 2841** These routines form the "result set query" interface. 2842** 2843** These routines return information about a single column of the current 2844** result row of a query. In every case the first argument is a pointer 2845** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 2846** that was returned from [sqlite3_prepare_v2()] or one of its variants) 2847** and the second argument is the index of the column for which information 2848** should be returned. The leftmost column of the result set has the index 0. 2849** 2850** If the SQL statement does not currently point to a valid row, or if the 2851** column index is out of range, the result is undefined. 2852** These routines may only be called when the most recent call to 2853** [sqlite3_step()] has returned [SQLITE_ROW] and neither 2854** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 2855** If any of these routines are called after [sqlite3_reset()] or 2856** [sqlite3_finalize()] or after [sqlite3_step()] has returned 2857** something other than [SQLITE_ROW], the results are undefined. 2858** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 2859** are called from a different thread while any of these routines 2860** are pending, then the results are undefined. 2861** 2862** The sqlite3_column_type() routine returns the 2863** [SQLITE_INTEGER | datatype code] for the initial data type 2864** of the result column. The returned value is one of [SQLITE_INTEGER], 2865** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 2866** returned by sqlite3_column_type() is only meaningful if no type 2867** conversions have occurred as described below. After a type conversion, 2868** the value returned by sqlite3_column_type() is undefined. Future 2869** versions of SQLite may change the behavior of sqlite3_column_type() 2870** following a type conversion. 2871** 2872** If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 2873** routine returns the number of bytes in that BLOB or string. 2874** If the result is a UTF-16 string, then sqlite3_column_bytes() converts 2875** the string to UTF-8 and then returns the number of bytes. 2876** If the result is a numeric value then sqlite3_column_bytes() uses 2877** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 2878** the number of bytes in that string. 2879** The value returned does not include the zero terminator at the end 2880** of the string. For clarity: the value returned is the number of 2881** bytes in the string, not the number of characters. 2882** 2883** Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 2884** even empty strings, are always zero terminated. The return 2885** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary 2886** pointer, possibly even a NULL pointer. 2887** 2888** The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes() 2889** but leaves the result in UTF-16 in native byte order instead of UTF-8. 2890** The zero terminator is not included in this count. 2891** 2892** The object returned by [sqlite3_column_value()] is an 2893** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 2894** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 2895** If the [unprotected sqlite3_value] object returned by 2896** [sqlite3_column_value()] is used in any other way, including calls 2897** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 2898** or [sqlite3_value_bytes()], then the behavior is undefined. 2899** 2900** These routines attempt to convert the value where appropriate. For 2901** example, if the internal representation is FLOAT and a text result 2902** is requested, [sqlite3_snprintf()] is used internally to perform the 2903** conversion automatically. The following table details the conversions 2904** that are applied: 2905** 2906** <blockquote> 2907** <table border="1"> 2908** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 2909** 2910** <tr><td> NULL <td> INTEGER <td> Result is 0 2911** <tr><td> NULL <td> FLOAT <td> Result is 0.0 2912** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 2913** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 2914** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 2915** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 2916** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 2917** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 2918** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 2919** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 2920** <tr><td> TEXT <td> INTEGER <td> Use atoi() 2921** <tr><td> TEXT <td> FLOAT <td> Use atof() 2922** <tr><td> TEXT <td> BLOB <td> No change 2923** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 2924** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 2925** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 2926** </table> 2927** </blockquote> 2928** 2929** The table above makes reference to standard C library functions atoi() 2930** and atof(). SQLite does not really use these functions. It has its 2931** own equivalent internal routines. The atoi() and atof() names are 2932** used in the table for brevity and because they are familiar to most 2933** C programmers. 2934** 2935** Note that when type conversions occur, pointers returned by prior 2936** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 2937** sqlite3_column_text16() may be invalidated. 2938** Type conversions and pointer invalidations might occur 2939** in the following cases: 2940** 2941** <ul> 2942** <li> The initial content is a BLOB and sqlite3_column_text() or 2943** sqlite3_column_text16() is called. A zero-terminator might 2944** need to be added to the string.</li> 2945** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 2946** sqlite3_column_text16() is called. The content must be converted 2947** to UTF-16.</li> 2948** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 2949** sqlite3_column_text() is called. The content must be converted 2950** to UTF-8.</li> 2951** </ul> 2952** 2953** Conversions between UTF-16be and UTF-16le are always done in place and do 2954** not invalidate a prior pointer, though of course the content of the buffer 2955** that the prior pointer points to will have been modified. Other kinds 2956** of conversion are done in place when it is possible, but sometimes they 2957** are not possible and in those cases prior pointers are invalidated. 2958** 2959** The safest and easiest to remember policy is to invoke these routines 2960** in one of the following ways: 2961** 2962** <ul> 2963** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 2964** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 2965** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 2966** </ul> 2967** 2968** In other words, you should call sqlite3_column_text(), 2969** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 2970** into the desired format, then invoke sqlite3_column_bytes() or 2971** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 2972** to sqlite3_column_text() or sqlite3_column_blob() with calls to 2973** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 2974** with calls to sqlite3_column_bytes(). 2975** 2976** The pointers returned are valid until a type conversion occurs as 2977** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 2978** [sqlite3_finalize()] is called. The memory space used to hold strings 2979** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 2980** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 2981** [sqlite3_free()]. 2982** 2983** If a memory allocation error occurs during the evaluation of any 2984** of these routines, a default value is returned. The default value 2985** is either the integer 0, the floating point number 0.0, or a NULL 2986** pointer. Subsequent calls to [sqlite3_errcode()] will return 2987** [SQLITE_NOMEM]. 2988** 2989** Requirements: 2990** [H13803] [H13806] [H13809] [H13812] [H13815] [H13818] [H13821] [H13824] 2991** [H13827] [H13830] 2992*/ 2993const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 2994int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 2995int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 2996double sqlite3_column_double(sqlite3_stmt*, int iCol); 2997int sqlite3_column_int(sqlite3_stmt*, int iCol); 2998sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 2999const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3000const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3001int sqlite3_column_type(sqlite3_stmt*, int iCol); 3002sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3003 3004/* 3005** CAPI3REF: Destroy A Prepared Statement Object {H13300} <S70300><S30100> 3006** 3007** The sqlite3_finalize() function is called to delete a [prepared statement]. 3008** If the statement was executed successfully or not executed at all, then 3009** SQLITE_OK is returned. If execution of the statement failed then an 3010** [error code] or [extended error code] is returned. 3011** 3012** This routine can be called at any point during the execution of the 3013** [prepared statement]. If the virtual machine has not 3014** completed execution when this routine is called, that is like 3015** encountering an error or an [sqlite3_interrupt | interrupt]. 3016** Incomplete updates may be rolled back and transactions canceled, 3017** depending on the circumstances, and the 3018** [error code] returned will be [SQLITE_ABORT]. 3019** 3020** Requirements: 3021** [H11302] [H11304] 3022*/ 3023int sqlite3_finalize(sqlite3_stmt *pStmt); 3024 3025/* 3026** CAPI3REF: Reset A Prepared Statement Object {H13330} <S70300> 3027** 3028** The sqlite3_reset() function is called to reset a [prepared statement] 3029** object back to its initial state, ready to be re-executed. 3030** Any SQL statement variables that had values bound to them using 3031** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3032** Use [sqlite3_clear_bindings()] to reset the bindings. 3033** 3034** {H11332} The [sqlite3_reset(S)] interface resets the [prepared statement] S 3035** back to the beginning of its program. 3036** 3037** {H11334} If the most recent call to [sqlite3_step(S)] for the 3038** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3039** or if [sqlite3_step(S)] has never before been called on S, 3040** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3041** 3042** {H11336} If the most recent call to [sqlite3_step(S)] for the 3043** [prepared statement] S indicated an error, then 3044** [sqlite3_reset(S)] returns an appropriate [error code]. 3045** 3046** {H11338} The [sqlite3_reset(S)] interface does not change the values 3047** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3048*/ 3049int sqlite3_reset(sqlite3_stmt *pStmt); 3050 3051/* 3052** CAPI3REF: Create Or Redefine SQL Functions {H16100} <S20200> 3053** KEYWORDS: {function creation routines} 3054** KEYWORDS: {application-defined SQL function} 3055** KEYWORDS: {application-defined SQL functions} 3056** 3057** These two functions (collectively known as "function creation routines") 3058** are used to add SQL functions or aggregates or to redefine the behavior 3059** of existing SQL functions or aggregates. The only difference between the 3060** two is that the second parameter, the name of the (scalar) function or 3061** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16 3062** for sqlite3_create_function16(). 3063** 3064** The first parameter is the [database connection] to which the SQL 3065** function is to be added. If a single program uses more than one database 3066** connection internally, then SQL functions must be added individually to 3067** each database connection. 3068** 3069** The second parameter is the name of the SQL function to be created or 3070** redefined. The length of the name is limited to 255 bytes, exclusive of 3071** the zero-terminator. Note that the name length limit is in bytes, not 3072** characters. Any attempt to create a function with a longer name 3073** will result in [SQLITE_ERROR] being returned. 3074** 3075** The third parameter (nArg) 3076** is the number of arguments that the SQL function or 3077** aggregate takes. If this parameter is negative, then the SQL function or 3078** aggregate may take any number of arguments. 3079** 3080** The fourth parameter, eTextRep, specifies what 3081** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3082** its parameters. Any SQL function implementation should be able to work 3083** work with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3084** more efficient with one encoding than another. It is allowed to 3085** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3086** times with the same function but with different values of eTextRep. 3087** When multiple implementations of the same function are available, SQLite 3088** will pick the one that involves the least amount of data conversion. 3089** If there is only a single implementation which does not care what text 3090** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3091** 3092** The fifth parameter is an arbitrary pointer. The implementation of the 3093** function can gain access to this pointer using [sqlite3_user_data()]. 3094** 3095** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are 3096** pointers to C-language functions that implement the SQL function or 3097** aggregate. A scalar SQL function requires an implementation of the xFunc 3098** callback only, NULL pointers should be passed as the xStep and xFinal 3099** parameters. An aggregate SQL function requires an implementation of xStep 3100** and xFinal and NULL should be passed for xFunc. To delete an existing 3101** SQL function or aggregate, pass NULL for all three function callbacks. 3102** 3103** It is permitted to register multiple implementations of the same 3104** functions with the same name but with either differing numbers of 3105** arguments or differing preferred text encodings. SQLite will use 3106** the implementation most closely matches the way in which the 3107** SQL function is used. A function implementation with a non-negative 3108** nArg parameter is a better match than a function implementation with 3109** a negative nArg. A function where the preferred text encoding 3110** matches the database encoding is a better 3111** match than a function where the encoding is different. 3112** A function where the encoding difference is between UTF16le and UTF16be 3113** is a closer match than a function where the encoding difference is 3114** between UTF8 and UTF16. 3115** 3116** Built-in functions may be overloaded by new application-defined functions. 3117** The first application-defined function with a given name overrides all 3118** built-in functions in the same [database connection] with the same name. 3119** Subsequent application-defined functions of the same name only override 3120** prior application-defined functions that are an exact match for the 3121** number of parameters and preferred encoding. 3122** 3123** An application-defined function is permitted to call other 3124** SQLite interfaces. However, such calls must not 3125** close the database connection nor finalize or reset the prepared 3126** statement in which the function is running. 3127** 3128** Requirements: 3129** [H16103] [H16106] [H16109] [H16112] [H16118] [H16121] [H16124] [H16127] 3130** [H16130] [H16133] [H16136] [H16139] [H16142] 3131*/ 3132int sqlite3_create_function( 3133 sqlite3 *db, 3134 const char *zFunctionName, 3135 int nArg, 3136 int eTextRep, 3137 void *pApp, 3138 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3139 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3140 void (*xFinal)(sqlite3_context*) 3141); 3142int sqlite3_create_function16( 3143 sqlite3 *db, 3144 const void *zFunctionName, 3145 int nArg, 3146 int eTextRep, 3147 void *pApp, 3148 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3149 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3150 void (*xFinal)(sqlite3_context*) 3151); 3152 3153/* 3154** CAPI3REF: Text Encodings {H10267} <S50200> <H16100> 3155** 3156** These constant define integer codes that represent the various 3157** text encodings supported by SQLite. 3158*/ 3159#define SQLITE_UTF8 1 3160#define SQLITE_UTF16LE 2 3161#define SQLITE_UTF16BE 3 3162#define SQLITE_UTF16 4 /* Use native byte order */ 3163#define SQLITE_ANY 5 /* sqlite3_create_function only */ 3164#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3165 3166/* 3167** CAPI3REF: Deprecated Functions 3168** DEPRECATED 3169** 3170** These functions are [deprecated]. In order to maintain 3171** backwards compatibility with older code, these functions continue 3172** to be supported. However, new applications should avoid 3173** the use of these functions. To help encourage people to avoid 3174** using these functions, we are not going to tell you what they do. 3175*/ 3176#ifndef SQLITE_OMIT_DEPRECATED 3177SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3178SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3179SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3180SQLITE_DEPRECATED int sqlite3_global_recover(void); 3181SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3182SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3183#endif 3184 3185/* 3186** CAPI3REF: Obtaining SQL Function Parameter Values {H15100} <S20200> 3187** 3188** The C-language implementation of SQL functions and aggregates uses 3189** this set of interface routines to access the parameter values on 3190** the function or aggregate. 3191** 3192** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3193** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3194** define callbacks that implement the SQL functions and aggregates. 3195** The 4th parameter to these callbacks is an array of pointers to 3196** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3197** each parameter to the SQL function. These routines are used to 3198** extract values from the [sqlite3_value] objects. 3199** 3200** These routines work only with [protected sqlite3_value] objects. 3201** Any attempt to use these routines on an [unprotected sqlite3_value] 3202** object results in undefined behavior. 3203** 3204** These routines work just like the corresponding [column access functions] 3205** except that these routines take a single [protected sqlite3_value] object 3206** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3207** 3208** The sqlite3_value_text16() interface extracts a UTF-16 string 3209** in the native byte-order of the host machine. The 3210** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3211** extract UTF-16 strings as big-endian and little-endian respectively. 3212** 3213** The sqlite3_value_numeric_type() interface attempts to apply 3214** numeric affinity to the value. This means that an attempt is 3215** made to convert the value to an integer or floating point. If 3216** such a conversion is possible without loss of information (in other 3217** words, if the value is a string that looks like a number) 3218** then the conversion is performed. Otherwise no conversion occurs. 3219** The [SQLITE_INTEGER | datatype] after conversion is returned. 3220** 3221** Please pay particular attention to the fact that the pointer returned 3222** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3223** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3224** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3225** or [sqlite3_value_text16()]. 3226** 3227** These routines must be called from the same thread as 3228** the SQL function that supplied the [sqlite3_value*] parameters. 3229** 3230** Requirements: 3231** [H15103] [H15106] [H15109] [H15112] [H15115] [H15118] [H15121] [H15124] 3232** [H15127] [H15130] [H15133] [H15136] 3233*/ 3234const void *sqlite3_value_blob(sqlite3_value*); 3235int sqlite3_value_bytes(sqlite3_value*); 3236int sqlite3_value_bytes16(sqlite3_value*); 3237double sqlite3_value_double(sqlite3_value*); 3238int sqlite3_value_int(sqlite3_value*); 3239sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3240const unsigned char *sqlite3_value_text(sqlite3_value*); 3241const void *sqlite3_value_text16(sqlite3_value*); 3242const void *sqlite3_value_text16le(sqlite3_value*); 3243const void *sqlite3_value_text16be(sqlite3_value*); 3244int sqlite3_value_type(sqlite3_value*); 3245int sqlite3_value_numeric_type(sqlite3_value*); 3246 3247/* 3248** CAPI3REF: Obtain Aggregate Function Context {H16210} <S20200> 3249** 3250** The implementation of aggregate SQL functions use this routine to allocate 3251** a structure for storing their state. 3252** 3253** The first time the sqlite3_aggregate_context() routine is called for a 3254** particular aggregate, SQLite allocates nBytes of memory, zeroes out that 3255** memory, and returns a pointer to it. On second and subsequent calls to 3256** sqlite3_aggregate_context() for the same aggregate function index, 3257** the same buffer is returned. The implementation of the aggregate can use 3258** the returned buffer to accumulate data. 3259** 3260** SQLite automatically frees the allocated buffer when the aggregate 3261** query concludes. 3262** 3263** The first parameter should be a copy of the 3264** [sqlite3_context | SQL function context] that is the first parameter 3265** to the callback routine that implements the aggregate function. 3266** 3267** This routine must be called from the same thread in which 3268** the aggregate SQL function is running. 3269** 3270** Requirements: 3271** [H16211] [H16213] [H16215] [H16217] 3272*/ 3273void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 3274 3275/* 3276** CAPI3REF: User Data For Functions {H16240} <S20200> 3277** 3278** The sqlite3_user_data() interface returns a copy of 3279** the pointer that was the pUserData parameter (the 5th parameter) 3280** of the [sqlite3_create_function()] 3281** and [sqlite3_create_function16()] routines that originally 3282** registered the application defined function. {END} 3283** 3284** This routine must be called from the same thread in which 3285** the application-defined function is running. 3286** 3287** Requirements: 3288** [H16243] 3289*/ 3290void *sqlite3_user_data(sqlite3_context*); 3291 3292/* 3293** CAPI3REF: Database Connection For Functions {H16250} <S60600><S20200> 3294** 3295** The sqlite3_context_db_handle() interface returns a copy of 3296** the pointer to the [database connection] (the 1st parameter) 3297** of the [sqlite3_create_function()] 3298** and [sqlite3_create_function16()] routines that originally 3299** registered the application defined function. 3300** 3301** Requirements: 3302** [H16253] 3303*/ 3304sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 3305 3306/* 3307** CAPI3REF: Function Auxiliary Data {H16270} <S20200> 3308** 3309** The following two functions may be used by scalar SQL functions to 3310** associate metadata with argument values. If the same value is passed to 3311** multiple invocations of the same SQL function during query execution, under 3312** some circumstances the associated metadata may be preserved. This may 3313** be used, for example, to add a regular-expression matching scalar 3314** function. The compiled version of the regular expression is stored as 3315** metadata associated with the SQL value passed as the regular expression 3316** pattern. The compiled regular expression can be reused on multiple 3317** invocations of the same function so that the original pattern string 3318** does not need to be recompiled on each invocation. 3319** 3320** The sqlite3_get_auxdata() interface returns a pointer to the metadata 3321** associated by the sqlite3_set_auxdata() function with the Nth argument 3322** value to the application-defined function. If no metadata has been ever 3323** been set for the Nth argument of the function, or if the corresponding 3324** function parameter has changed since the meta-data was set, 3325** then sqlite3_get_auxdata() returns a NULL pointer. 3326** 3327** The sqlite3_set_auxdata() interface saves the metadata 3328** pointed to by its 3rd parameter as the metadata for the N-th 3329** argument of the application-defined function. Subsequent 3330** calls to sqlite3_get_auxdata() might return this data, if it has 3331** not been destroyed. 3332** If it is not NULL, SQLite will invoke the destructor 3333** function given by the 4th parameter to sqlite3_set_auxdata() on 3334** the metadata when the corresponding function parameter changes 3335** or when the SQL statement completes, whichever comes first. 3336** 3337** SQLite is free to call the destructor and drop metadata on any 3338** parameter of any function at any time. The only guarantee is that 3339** the destructor will be called before the metadata is dropped. 3340** 3341** In practice, metadata is preserved between function calls for 3342** expressions that are constant at compile time. This includes literal 3343** values and SQL variables. 3344** 3345** These routines must be called from the same thread in which 3346** the SQL function is running. 3347** 3348** Requirements: 3349** [H16272] [H16274] [H16276] [H16277] [H16278] [H16279] 3350*/ 3351void *sqlite3_get_auxdata(sqlite3_context*, int N); 3352void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 3353 3354 3355/* 3356** CAPI3REF: Constants Defining Special Destructor Behavior {H10280} <S30100> 3357** 3358** These are special values for the destructor that is passed in as the 3359** final argument to routines like [sqlite3_result_blob()]. If the destructor 3360** argument is SQLITE_STATIC, it means that the content pointer is constant 3361** and will never change. It does not need to be destroyed. The 3362** SQLITE_TRANSIENT value means that the content will likely change in 3363** the near future and that SQLite should make its own private copy of 3364** the content before returning. 3365** 3366** The typedef is necessary to work around problems in certain 3367** C++ compilers. See ticket #2191. 3368*/ 3369typedef void (*sqlite3_destructor_type)(void*); 3370#define SQLITE_STATIC ((sqlite3_destructor_type)0) 3371#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 3372 3373/* 3374** CAPI3REF: Setting The Result Of An SQL Function {H16400} <S20200> 3375** 3376** These routines are used by the xFunc or xFinal callbacks that 3377** implement SQL functions and aggregates. See 3378** [sqlite3_create_function()] and [sqlite3_create_function16()] 3379** for additional information. 3380** 3381** These functions work very much like the [parameter binding] family of 3382** functions used to bind values to host parameters in prepared statements. 3383** Refer to the [SQL parameter] documentation for additional information. 3384** 3385** The sqlite3_result_blob() interface sets the result from 3386** an application-defined function to be the BLOB whose content is pointed 3387** to by the second parameter and which is N bytes long where N is the 3388** third parameter. 3389** 3390** The sqlite3_result_zeroblob() interfaces set the result of 3391** the application-defined function to be a BLOB containing all zero 3392** bytes and N bytes in size, where N is the value of the 2nd parameter. 3393** 3394** The sqlite3_result_double() interface sets the result from 3395** an application-defined function to be a floating point value specified 3396** by its 2nd argument. 3397** 3398** The sqlite3_result_error() and sqlite3_result_error16() functions 3399** cause the implemented SQL function to throw an exception. 3400** SQLite uses the string pointed to by the 3401** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 3402** as the text of an error message. SQLite interprets the error 3403** message string from sqlite3_result_error() as UTF-8. SQLite 3404** interprets the string from sqlite3_result_error16() as UTF-16 in native 3405** byte order. If the third parameter to sqlite3_result_error() 3406** or sqlite3_result_error16() is negative then SQLite takes as the error 3407** message all text up through the first zero character. 3408** If the third parameter to sqlite3_result_error() or 3409** sqlite3_result_error16() is non-negative then SQLite takes that many 3410** bytes (not characters) from the 2nd parameter as the error message. 3411** The sqlite3_result_error() and sqlite3_result_error16() 3412** routines make a private copy of the error message text before 3413** they return. Hence, the calling function can deallocate or 3414** modify the text after they return without harm. 3415** The sqlite3_result_error_code() function changes the error code 3416** returned by SQLite as a result of an error in a function. By default, 3417** the error code is SQLITE_ERROR. A subsequent call to sqlite3_result_error() 3418** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 3419** 3420** The sqlite3_result_toobig() interface causes SQLite to throw an error 3421** indicating that a string or BLOB is to long to represent. 3422** 3423** The sqlite3_result_nomem() interface causes SQLite to throw an error 3424** indicating that a memory allocation failed. 3425** 3426** The sqlite3_result_int() interface sets the return value 3427** of the application-defined function to be the 32-bit signed integer 3428** value given in the 2nd argument. 3429** The sqlite3_result_int64() interface sets the return value 3430** of the application-defined function to be the 64-bit signed integer 3431** value given in the 2nd argument. 3432** 3433** The sqlite3_result_null() interface sets the return value 3434** of the application-defined function to be NULL. 3435** 3436** The sqlite3_result_text(), sqlite3_result_text16(), 3437** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 3438** set the return value of the application-defined function to be 3439** a text string which is represented as UTF-8, UTF-16 native byte order, 3440** UTF-16 little endian, or UTF-16 big endian, respectively. 3441** SQLite takes the text result from the application from 3442** the 2nd parameter of the sqlite3_result_text* interfaces. 3443** If the 3rd parameter to the sqlite3_result_text* interfaces 3444** is negative, then SQLite takes result text from the 2nd parameter 3445** through the first zero character. 3446** If the 3rd parameter to the sqlite3_result_text* interfaces 3447** is non-negative, then as many bytes (not characters) of the text 3448** pointed to by the 2nd parameter are taken as the application-defined 3449** function result. 3450** If the 4th parameter to the sqlite3_result_text* interfaces 3451** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 3452** function as the destructor on the text or BLOB result when it has 3453** finished using that result. 3454** If the 4th parameter to the sqlite3_result_text* interfaces or 3455** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 3456** assumes that the text or BLOB result is in constant space and does not 3457** copy the it or call a destructor when it has finished using that result. 3458** If the 4th parameter to the sqlite3_result_text* interfaces 3459** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 3460** then SQLite makes a copy of the result into space obtained from 3461** from [sqlite3_malloc()] before it returns. 3462** 3463** The sqlite3_result_value() interface sets the result of 3464** the application-defined function to be a copy the 3465** [unprotected sqlite3_value] object specified by the 2nd parameter. The 3466** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 3467** so that the [sqlite3_value] specified in the parameter may change or 3468** be deallocated after sqlite3_result_value() returns without harm. 3469** A [protected sqlite3_value] object may always be used where an 3470** [unprotected sqlite3_value] object is required, so either 3471** kind of [sqlite3_value] object can be used with this interface. 3472** 3473** If these routines are called from within the different thread 3474** than the one containing the application-defined function that received 3475** the [sqlite3_context] pointer, the results are undefined. 3476** 3477** Requirements: 3478** [H16403] [H16406] [H16409] [H16412] [H16415] [H16418] [H16421] [H16424] 3479** [H16427] [H16430] [H16433] [H16436] [H16439] [H16442] [H16445] [H16448] 3480** [H16451] [H16454] [H16457] [H16460] [H16463] 3481*/ 3482void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 3483void sqlite3_result_double(sqlite3_context*, double); 3484void sqlite3_result_error(sqlite3_context*, const char*, int); 3485void sqlite3_result_error16(sqlite3_context*, const void*, int); 3486void sqlite3_result_error_toobig(sqlite3_context*); 3487void sqlite3_result_error_nomem(sqlite3_context*); 3488void sqlite3_result_error_code(sqlite3_context*, int); 3489void sqlite3_result_int(sqlite3_context*, int); 3490void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 3491void sqlite3_result_null(sqlite3_context*); 3492void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 3493void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 3494void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 3495void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 3496void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 3497void sqlite3_result_zeroblob(sqlite3_context*, int n); 3498 3499/* 3500** CAPI3REF: Define New Collating Sequences {H16600} <S20300> 3501** 3502** These functions are used to add new collation sequences to the 3503** [database connection] specified as the first argument. 3504** 3505** The name of the new collation sequence is specified as a UTF-8 string 3506** for sqlite3_create_collation() and sqlite3_create_collation_v2() 3507** and a UTF-16 string for sqlite3_create_collation16(). In all cases 3508** the name is passed as the second function argument. 3509** 3510** The third argument may be one of the constants [SQLITE_UTF8], 3511** [SQLITE_UTF16LE], or [SQLITE_UTF16BE], indicating that the user-supplied 3512** routine expects to be passed pointers to strings encoded using UTF-8, 3513** UTF-16 little-endian, or UTF-16 big-endian, respectively. The 3514** third argument might also be [SQLITE_UTF16] to indicate that the routine 3515** expects pointers to be UTF-16 strings in the native byte order, or the 3516** argument can be [SQLITE_UTF16_ALIGNED] if the 3517** the routine expects pointers to 16-bit word aligned strings 3518** of UTF-16 in the native byte order. 3519** 3520** A pointer to the user supplied routine must be passed as the fifth 3521** argument. If it is NULL, this is the same as deleting the collation 3522** sequence (so that SQLite cannot call it anymore). 3523** Each time the application supplied function is invoked, it is passed 3524** as its first parameter a copy of the void* passed as the fourth argument 3525** to sqlite3_create_collation() or sqlite3_create_collation16(). 3526** 3527** The remaining arguments to the application-supplied routine are two strings, 3528** each represented by a (length, data) pair and encoded in the encoding 3529** that was passed as the third argument when the collation sequence was 3530** registered. {END} The application defined collation routine should 3531** return negative, zero or positive if the first string is less than, 3532** equal to, or greater than the second string. i.e. (STRING1 - STRING2). 3533** 3534** The sqlite3_create_collation_v2() works like sqlite3_create_collation() 3535** except that it takes an extra argument which is a destructor for 3536** the collation. The destructor is called when the collation is 3537** destroyed and is passed a copy of the fourth parameter void* pointer 3538** of the sqlite3_create_collation_v2(). 3539** Collations are destroyed when they are overridden by later calls to the 3540** collation creation functions or when the [database connection] is closed 3541** using [sqlite3_close()]. 3542** 3543** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 3544** 3545** Requirements: 3546** [H16603] [H16604] [H16606] [H16609] [H16612] [H16615] [H16618] [H16621] 3547** [H16624] [H16627] [H16630] 3548*/ 3549int sqlite3_create_collation( 3550 sqlite3*, 3551 const char *zName, 3552 int eTextRep, 3553 void*, 3554 int(*xCompare)(void*,int,const void*,int,const void*) 3555); 3556int sqlite3_create_collation_v2( 3557 sqlite3*, 3558 const char *zName, 3559 int eTextRep, 3560 void*, 3561 int(*xCompare)(void*,int,const void*,int,const void*), 3562 void(*xDestroy)(void*) 3563); 3564int sqlite3_create_collation16( 3565 sqlite3*, 3566 const void *zName, 3567 int eTextRep, 3568 void*, 3569 int(*xCompare)(void*,int,const void*,int,const void*) 3570); 3571 3572/* 3573** CAPI3REF: Collation Needed Callbacks {H16700} <S20300> 3574** 3575** To avoid having to register all collation sequences before a database 3576** can be used, a single callback function may be registered with the 3577** [database connection] to be called whenever an undefined collation 3578** sequence is required. 3579** 3580** If the function is registered using the sqlite3_collation_needed() API, 3581** then it is passed the names of undefined collation sequences as strings 3582** encoded in UTF-8. {H16703} If sqlite3_collation_needed16() is used, 3583** the names are passed as UTF-16 in machine native byte order. 3584** A call to either function replaces any existing callback. 3585** 3586** When the callback is invoked, the first argument passed is a copy 3587** of the second argument to sqlite3_collation_needed() or 3588** sqlite3_collation_needed16(). The second argument is the database 3589** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 3590** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 3591** sequence function required. The fourth parameter is the name of the 3592** required collation sequence. 3593** 3594** The callback function should register the desired collation using 3595** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 3596** [sqlite3_create_collation_v2()]. 3597** 3598** Requirements: 3599** [H16702] [H16704] [H16706] 3600*/ 3601int sqlite3_collation_needed( 3602 sqlite3*, 3603 void*, 3604 void(*)(void*,sqlite3*,int eTextRep,const char*) 3605); 3606int sqlite3_collation_needed16( 3607 sqlite3*, 3608 void*, 3609 void(*)(void*,sqlite3*,int eTextRep,const void*) 3610); 3611 3612/* 3613** Specify the key for an encrypted database. This routine should be 3614** called right after sqlite3_open(). 3615** 3616** The code to implement this API is not available in the public release 3617** of SQLite. 3618*/ 3619int sqlite3_key( 3620 sqlite3 *db, /* Database to be rekeyed */ 3621 const void *pKey, int nKey /* The key */ 3622); 3623 3624/* 3625** Change the key on an open database. If the current database is not 3626** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 3627** database is decrypted. 3628** 3629** The code to implement this API is not available in the public release 3630** of SQLite. 3631*/ 3632int sqlite3_rekey( 3633 sqlite3 *db, /* Database to be rekeyed */ 3634 const void *pKey, int nKey /* The new key */ 3635); 3636 3637/* 3638** CAPI3REF: Suspend Execution For A Short Time {H10530} <S40410> 3639** 3640** The sqlite3_sleep() function causes the current thread to suspend execution 3641** for at least a number of milliseconds specified in its parameter. 3642** 3643** If the operating system does not support sleep requests with 3644** millisecond time resolution, then the time will be rounded up to 3645** the nearest second. The number of milliseconds of sleep actually 3646** requested from the operating system is returned. 3647** 3648** SQLite implements this interface by calling the xSleep() 3649** method of the default [sqlite3_vfs] object. 3650** 3651** Requirements: [H10533] [H10536] 3652*/ 3653int sqlite3_sleep(int); 3654 3655/* 3656** CAPI3REF: Name Of The Folder Holding Temporary Files {H10310} <S20000> 3657** 3658** If this global variable is made to point to a string which is 3659** the name of a folder (a.k.a. directory), then all temporary files 3660** created by SQLite will be placed in that directory. If this variable 3661** is a NULL pointer, then SQLite performs a search for an appropriate 3662** temporary file directory. 3663** 3664** It is not safe to read or modify this variable in more than one 3665** thread at a time. It is not safe to read or modify this variable 3666** if a [database connection] is being used at the same time in a separate 3667** thread. 3668** It is intended that this variable be set once 3669** as part of process initialization and before any SQLite interface 3670** routines have been called and that this variable remain unchanged 3671** thereafter. 3672** 3673** The [temp_store_directory pragma] may modify this variable and cause 3674** it to point to memory obtained from [sqlite3_malloc]. Furthermore, 3675** the [temp_store_directory pragma] always assumes that any string 3676** that this variable points to is held in memory obtained from 3677** [sqlite3_malloc] and the pragma may attempt to free that memory 3678** using [sqlite3_free]. 3679** Hence, if this variable is modified directly, either it should be 3680** made NULL or made to point to memory obtained from [sqlite3_malloc] 3681** or else the use of the [temp_store_directory pragma] should be avoided. 3682*/ 3683SQLITE_EXTERN char *sqlite3_temp_directory; 3684 3685/* 3686** CAPI3REF: Test For Auto-Commit Mode {H12930} <S60200> 3687** KEYWORDS: {autocommit mode} 3688** 3689** The sqlite3_get_autocommit() interface returns non-zero or 3690** zero if the given database connection is or is not in autocommit mode, 3691** respectively. Autocommit mode is on by default. 3692** Autocommit mode is disabled by a [BEGIN] statement. 3693** Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 3694** 3695** If certain kinds of errors occur on a statement within a multi-statement 3696** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 3697** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 3698** transaction might be rolled back automatically. The only way to 3699** find out whether SQLite automatically rolled back the transaction after 3700** an error is to use this function. 3701** 3702** If another thread changes the autocommit status of the database 3703** connection while this routine is running, then the return value 3704** is undefined. 3705** 3706** Requirements: [H12931] [H12932] [H12933] [H12934] 3707*/ 3708int sqlite3_get_autocommit(sqlite3*); 3709 3710/* 3711** CAPI3REF: Find The Database Handle Of A Prepared Statement {H13120} <S60600> 3712** 3713** The sqlite3_db_handle interface returns the [database connection] handle 3714** to which a [prepared statement] belongs. The [database connection] 3715** returned by sqlite3_db_handle is the same [database connection] that was the first argument 3716** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 3717** create the statement in the first place. 3718** 3719** Requirements: [H13123] 3720*/ 3721sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 3722 3723/* 3724** CAPI3REF: Find the next prepared statement {H13140} <S60600> 3725** 3726** This interface returns a pointer to the next [prepared statement] after 3727** pStmt associated with the [database connection] pDb. If pStmt is NULL 3728** then this interface returns a pointer to the first prepared statement 3729** associated with the database connection pDb. If no prepared statement 3730** satisfies the conditions of this routine, it returns NULL. 3731** 3732** The [database connection] pointer D in a call to 3733** [sqlite3_next_stmt(D,S)] must refer to an open database 3734** connection and in particular must not be a NULL pointer. 3735** 3736** Requirements: [H13143] [H13146] [H13149] [H13152] 3737*/ 3738sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 3739 3740/* 3741** CAPI3REF: Commit And Rollback Notification Callbacks {H12950} <S60400> 3742** 3743** The sqlite3_commit_hook() interface registers a callback 3744** function to be invoked whenever a transaction is [COMMIT | committed]. 3745** Any callback set by a previous call to sqlite3_commit_hook() 3746** for the same database connection is overridden. 3747** The sqlite3_rollback_hook() interface registers a callback 3748** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 3749** Any callback set by a previous call to sqlite3_commit_hook() 3750** for the same database connection is overridden. 3751** The pArg argument is passed through to the callback. 3752** If the callback on a commit hook function returns non-zero, 3753** then the commit is converted into a rollback. 3754** 3755** If another function was previously registered, its 3756** pArg value is returned. Otherwise NULL is returned. 3757** 3758** The callback implementation must not do anything that will modify 3759** the database connection that invoked the callback. Any actions 3760** to modify the database connection must be deferred until after the 3761** completion of the [sqlite3_step()] call that triggered the commit 3762** or rollback hook in the first place. 3763** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3764** database connections for the meaning of "modify" in this paragraph. 3765** 3766** Registering a NULL function disables the callback. 3767** 3768** When the commit hook callback routine returns zero, the [COMMIT] 3769** operation is allowed to continue normally. If the commit hook 3770** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 3771** The rollback hook is invoked on a rollback that results from a commit 3772** hook returning non-zero, just as it would be with any other rollback. 3773** 3774** For the purposes of this API, a transaction is said to have been 3775** rolled back if an explicit "ROLLBACK" statement is executed, or 3776** an error or constraint causes an implicit rollback to occur. 3777** The rollback callback is not invoked if a transaction is 3778** automatically rolled back because the database connection is closed. 3779** The rollback callback is not invoked if a transaction is 3780** rolled back because a commit callback returned non-zero. 3781** <todo> Check on this </todo> 3782** 3783** See also the [sqlite3_update_hook()] interface. 3784** 3785** Requirements: 3786** [H12951] [H12952] [H12953] [H12954] [H12955] 3787** [H12961] [H12962] [H12963] [H12964] 3788*/ 3789void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 3790void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 3791 3792/* 3793** CAPI3REF: Data Change Notification Callbacks {H12970} <S60400> 3794** 3795** The sqlite3_update_hook() interface registers a callback function 3796** with the [database connection] identified by the first argument 3797** to be invoked whenever a row is updated, inserted or deleted. 3798** Any callback set by a previous call to this function 3799** for the same database connection is overridden. 3800** 3801** The second argument is a pointer to the function to invoke when a 3802** row is updated, inserted or deleted. 3803** The first argument to the callback is a copy of the third argument 3804** to sqlite3_update_hook(). 3805** The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 3806** or [SQLITE_UPDATE], depending on the operation that caused the callback 3807** to be invoked. 3808** The third and fourth arguments to the callback contain pointers to the 3809** database and table name containing the affected row. 3810** The final callback parameter is the [rowid] of the row. 3811** In the case of an update, this is the [rowid] after the update takes place. 3812** 3813** The update hook is not invoked when internal system tables are 3814** modified (i.e. sqlite_master and sqlite_sequence). 3815** 3816** In the current implementation, the update hook 3817** is not invoked when duplication rows are deleted because of an 3818** [ON CONFLICT | ON CONFLICT REPLACE] clause. Nor is the update hook 3819** invoked when rows are deleted using the [truncate optimization]. 3820** The exceptions defined in this paragraph might change in a future 3821** release of SQLite. 3822** 3823** The update hook implementation must not do anything that will modify 3824** the database connection that invoked the update hook. Any actions 3825** to modify the database connection must be deferred until after the 3826** completion of the [sqlite3_step()] call that triggered the update hook. 3827** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3828** database connections for the meaning of "modify" in this paragraph. 3829** 3830** If another function was previously registered, its pArg value 3831** is returned. Otherwise NULL is returned. 3832** 3833** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 3834** interfaces. 3835** 3836** Requirements: 3837** [H12971] [H12973] [H12975] [H12977] [H12979] [H12981] [H12983] [H12986] 3838*/ 3839void *sqlite3_update_hook( 3840 sqlite3*, 3841 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 3842 void* 3843); 3844 3845/* 3846** CAPI3REF: Enable Or Disable Shared Pager Cache {H10330} <S30900> 3847** KEYWORDS: {shared cache} {shared cache mode} 3848** 3849** This routine enables or disables the sharing of the database cache 3850** and schema data structures between [database connection | connections] 3851** to the same database. Sharing is enabled if the argument is true 3852** and disabled if the argument is false. 3853** 3854** Cache sharing is enabled and disabled for an entire process. 3855** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 3856** sharing was enabled or disabled for each thread separately. 3857** 3858** The cache sharing mode set by this interface effects all subsequent 3859** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 3860** Existing database connections continue use the sharing mode 3861** that was in effect at the time they were opened. 3862** 3863** Virtual tables cannot be used with a shared cache. When shared 3864** cache is enabled, the [sqlite3_create_module()] API used to register 3865** virtual tables will always return an error. 3866** 3867** This routine returns [SQLITE_OK] if shared cache was enabled or disabled 3868** successfully. An [error code] is returned otherwise. 3869** 3870** Shared cache is disabled by default. But this might change in 3871** future releases of SQLite. Applications that care about shared 3872** cache setting should set it explicitly. 3873** 3874** See Also: [SQLite Shared-Cache Mode] 3875** 3876** Requirements: [H10331] [H10336] [H10337] [H10339] 3877*/ 3878int sqlite3_enable_shared_cache(int); 3879 3880/* 3881** CAPI3REF: Attempt To Free Heap Memory {H17340} <S30220> 3882** 3883** The sqlite3_release_memory() interface attempts to free N bytes 3884** of heap memory by deallocating non-essential memory allocations 3885** held by the database library. {END} Memory used to cache database 3886** pages to improve performance is an example of non-essential memory. 3887** sqlite3_release_memory() returns the number of bytes actually freed, 3888** which might be more or less than the amount requested. 3889** 3890** Requirements: [H17341] [H17342] 3891*/ 3892int sqlite3_release_memory(int); 3893 3894/* 3895** CAPI3REF: Impose A Limit On Heap Size {H17350} <S30220> 3896** 3897** The sqlite3_soft_heap_limit() interface places a "soft" limit 3898** on the amount of heap memory that may be allocated by SQLite. 3899** If an internal allocation is requested that would exceed the 3900** soft heap limit, [sqlite3_release_memory()] is invoked one or 3901** more times to free up some space before the allocation is performed. 3902** 3903** The limit is called "soft", because if [sqlite3_release_memory()] 3904** cannot free sufficient memory to prevent the limit from being exceeded, 3905** the memory is allocated anyway and the current operation proceeds. 3906** 3907** A negative or zero value for N means that there is no soft heap limit and 3908** [sqlite3_release_memory()] will only be called when memory is exhausted. 3909** The default value for the soft heap limit is zero. 3910** 3911** SQLite makes a best effort to honor the soft heap limit. 3912** But if the soft heap limit cannot be honored, execution will 3913** continue without error or notification. This is why the limit is 3914** called a "soft" limit. It is advisory only. 3915** 3916** Prior to SQLite version 3.5.0, this routine only constrained the memory 3917** allocated by a single thread - the same thread in which this routine 3918** runs. Beginning with SQLite version 3.5.0, the soft heap limit is 3919** applied to all threads. The value specified for the soft heap limit 3920** is an upper bound on the total memory allocation for all threads. In 3921** version 3.5.0 there is no mechanism for limiting the heap usage for 3922** individual threads. 3923** 3924** Requirements: 3925** [H16351] [H16352] [H16353] [H16354] [H16355] [H16358] 3926*/ 3927void sqlite3_soft_heap_limit(int); 3928 3929/* 3930** CAPI3REF: Extract Metadata About A Column Of A Table {H12850} <S60300> 3931** 3932** This routine returns metadata about a specific column of a specific 3933** database table accessible using the [database connection] handle 3934** passed as the first function argument. 3935** 3936** The column is identified by the second, third and fourth parameters to 3937** this function. The second parameter is either the name of the database 3938** (i.e. "main", "temp" or an attached database) containing the specified 3939** table or NULL. If it is NULL, then all attached databases are searched 3940** for the table using the same algorithm used by the database engine to 3941** resolve unqualified table references. 3942** 3943** The third and fourth parameters to this function are the table and column 3944** name of the desired column, respectively. Neither of these parameters 3945** may be NULL. 3946** 3947** Metadata is returned by writing to the memory locations passed as the 5th 3948** and subsequent parameters to this function. Any of these arguments may be 3949** NULL, in which case the corresponding element of metadata is omitted. 3950** 3951** <blockquote> 3952** <table border="1"> 3953** <tr><th> Parameter <th> Output<br>Type <th> Description 3954** 3955** <tr><td> 5th <td> const char* <td> Data type 3956** <tr><td> 6th <td> const char* <td> Name of default collation sequence 3957** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 3958** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 3959** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 3960** </table> 3961** </blockquote> 3962** 3963** The memory pointed to by the character pointers returned for the 3964** declaration type and collation sequence is valid only until the next 3965** call to any SQLite API function. 3966** 3967** If the specified table is actually a view, an [error code] is returned. 3968** 3969** If the specified column is "rowid", "oid" or "_rowid_" and an 3970** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 3971** parameters are set for the explicitly declared column. If there is no 3972** explicitly declared [INTEGER PRIMARY KEY] column, then the output 3973** parameters are set as follows: 3974** 3975** <pre> 3976** data type: "INTEGER" 3977** collation sequence: "BINARY" 3978** not null: 0 3979** primary key: 1 3980** auto increment: 0 3981** </pre> 3982** 3983** This function may load one or more schemas from database files. If an 3984** error occurs during this process, or if the requested table or column 3985** cannot be found, an [error code] is returned and an error message left 3986** in the [database connection] (to be retrieved using sqlite3_errmsg()). 3987** 3988** This API is only available if the library was compiled with the 3989** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 3990*/ 3991int sqlite3_table_column_metadata( 3992 sqlite3 *db, /* Connection handle */ 3993 const char *zDbName, /* Database name or NULL */ 3994 const char *zTableName, /* Table name */ 3995 const char *zColumnName, /* Column name */ 3996 char const **pzDataType, /* OUTPUT: Declared data type */ 3997 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 3998 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 3999 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4000 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4001); 4002 4003/* 4004** CAPI3REF: Load An Extension {H12600} <S20500> 4005** 4006** This interface loads an SQLite extension library from the named file. 4007** 4008** {H12601} The sqlite3_load_extension() interface attempts to load an 4009** SQLite extension library contained in the file zFile. 4010** 4011** {H12602} The entry point is zProc. 4012** 4013** {H12603} zProc may be 0, in which case the name of the entry point 4014** defaults to "sqlite3_extension_init". 4015** 4016** {H12604} The sqlite3_load_extension() interface shall return 4017** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4018** 4019** {H12605} If an error occurs and pzErrMsg is not 0, then the 4020** [sqlite3_load_extension()] interface shall attempt to 4021** fill *pzErrMsg with error message text stored in memory 4022** obtained from [sqlite3_malloc()]. {END} The calling function 4023** should free this memory by calling [sqlite3_free()]. 4024** 4025** {H12606} Extension loading must be enabled using 4026** [sqlite3_enable_load_extension()] prior to calling this API, 4027** otherwise an error will be returned. 4028*/ 4029int sqlite3_load_extension( 4030 sqlite3 *db, /* Load the extension into this database connection */ 4031 const char *zFile, /* Name of the shared library containing extension */ 4032 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4033 char **pzErrMsg /* Put error message here if not 0 */ 4034); 4035 4036/* 4037** CAPI3REF: Enable Or Disable Extension Loading {H12620} <S20500> 4038** 4039** So as not to open security holes in older applications that are 4040** unprepared to deal with extension loading, and as a means of disabling 4041** extension loading while evaluating user-entered SQL, the following API 4042** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4043** 4044** Extension loading is off by default. See ticket #1863. 4045** 4046** {H12621} Call the sqlite3_enable_load_extension() routine with onoff==1 4047** to turn extension loading on and call it with onoff==0 to turn 4048** it back off again. 4049** 4050** {H12622} Extension loading is off by default. 4051*/ 4052int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4053 4054/* 4055** CAPI3REF: Automatically Load An Extensions {H12640} <S20500> 4056** 4057** This API can be invoked at program startup in order to register 4058** one or more statically linked extensions that will be available 4059** to all new [database connections]. {END} 4060** 4061** This routine stores a pointer to the extension in an array that is 4062** obtained from [sqlite3_malloc()]. If you run a memory leak checker 4063** on your program and it reports a leak because of this array, invoke 4064** [sqlite3_reset_auto_extension()] prior to shutdown to free the memory. 4065** 4066** {H12641} This function registers an extension entry point that is 4067** automatically invoked whenever a new [database connection] 4068** is opened using [sqlite3_open()], [sqlite3_open16()], 4069** or [sqlite3_open_v2()]. 4070** 4071** {H12642} Duplicate extensions are detected so calling this routine 4072** multiple times with the same extension is harmless. 4073** 4074** {H12643} This routine stores a pointer to the extension in an array 4075** that is obtained from [sqlite3_malloc()]. 4076** 4077** {H12644} Automatic extensions apply across all threads. 4078*/ 4079int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4080 4081/* 4082** CAPI3REF: Reset Automatic Extension Loading {H12660} <S20500> 4083** 4084** This function disables all previously registered automatic 4085** extensions. {END} It undoes the effect of all prior 4086** [sqlite3_auto_extension()] calls. 4087** 4088** {H12661} This function disables all previously registered 4089** automatic extensions. 4090** 4091** {H12662} This function disables automatic extensions in all threads. 4092*/ 4093void sqlite3_reset_auto_extension(void); 4094 4095/* 4096****** EXPERIMENTAL - subject to change without notice ************** 4097** 4098** The interface to the virtual-table mechanism is currently considered 4099** to be experimental. The interface might change in incompatible ways. 4100** If this is a problem for you, do not use the interface at this time. 4101** 4102** When the virtual-table mechanism stabilizes, we will declare the 4103** interface fixed, support it indefinitely, and remove this comment. 4104*/ 4105 4106/* 4107** Structures used by the virtual table interface 4108*/ 4109typedef struct sqlite3_vtab sqlite3_vtab; 4110typedef struct sqlite3_index_info sqlite3_index_info; 4111typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4112typedef struct sqlite3_module sqlite3_module; 4113 4114/* 4115** CAPI3REF: Virtual Table Object {H18000} <S20400> 4116** KEYWORDS: sqlite3_module {virtual table module} 4117** EXPERIMENTAL 4118** 4119** This structure, sometimes called a a "virtual table module", 4120** defines the implementation of a [virtual tables]. 4121** This structure consists mostly of methods for the module. 4122** 4123** A virtual table module is created by filling in a persistent 4124** instance of this structure and passing a pointer to that instance 4125** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4126** The registration remains valid until it is replaced by a different 4127** module or until the [database connection] closes. The content 4128** of this structure must not change while it is registered with 4129** any database connection. 4130*/ 4131struct sqlite3_module { 4132 int iVersion; 4133 int (*xCreate)(sqlite3*, void *pAux, 4134 int argc, const char *const*argv, 4135 sqlite3_vtab **ppVTab, char**); 4136 int (*xConnect)(sqlite3*, void *pAux, 4137 int argc, const char *const*argv, 4138 sqlite3_vtab **ppVTab, char**); 4139 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4140 int (*xDisconnect)(sqlite3_vtab *pVTab); 4141 int (*xDestroy)(sqlite3_vtab *pVTab); 4142 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4143 int (*xClose)(sqlite3_vtab_cursor*); 4144 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4145 int argc, sqlite3_value **argv); 4146 int (*xNext)(sqlite3_vtab_cursor*); 4147 int (*xEof)(sqlite3_vtab_cursor*); 4148 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4149 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4150 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4151 int (*xBegin)(sqlite3_vtab *pVTab); 4152 int (*xSync)(sqlite3_vtab *pVTab); 4153 int (*xCommit)(sqlite3_vtab *pVTab); 4154 int (*xRollback)(sqlite3_vtab *pVTab); 4155 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4156 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4157 void **ppArg); 4158 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4159}; 4160 4161/* 4162** CAPI3REF: Virtual Table Indexing Information {H18100} <S20400> 4163** KEYWORDS: sqlite3_index_info 4164** EXPERIMENTAL 4165** 4166** The sqlite3_index_info structure and its substructures is used to 4167** pass information into and receive the reply from the [xBestIndex] 4168** method of a [virtual table module]. The fields under **Inputs** are the 4169** inputs to xBestIndex and are read-only. xBestIndex inserts its 4170** results into the **Outputs** fields. 4171** 4172** The aConstraint[] array records WHERE clause constraints of the form: 4173** 4174** <pre>column OP expr</pre> 4175** 4176** where OP is =, <, <=, >, or >=. The particular operator is 4177** stored in aConstraint[].op. The index of the column is stored in 4178** aConstraint[].iColumn. aConstraint[].usable is TRUE if the 4179** expr on the right-hand side can be evaluated (and thus the constraint 4180** is usable) and false if it cannot. 4181** 4182** The optimizer automatically inverts terms of the form "expr OP column" 4183** and makes other simplifications to the WHERE clause in an attempt to 4184** get as many WHERE clause terms into the form shown above as possible. 4185** The aConstraint[] array only reports WHERE clause terms in the correct 4186** form that refer to the particular virtual table being queried. 4187** 4188** Information about the ORDER BY clause is stored in aOrderBy[]. 4189** Each term of aOrderBy records a column of the ORDER BY clause. 4190** 4191** The [xBestIndex] method must fill aConstraintUsage[] with information 4192** about what parameters to pass to xFilter. If argvIndex>0 then 4193** the right-hand side of the corresponding aConstraint[] is evaluated 4194** and becomes the argvIndex-th entry in argv. If aConstraintUsage[].omit 4195** is true, then the constraint is assumed to be fully handled by the 4196** virtual table and is not checked again by SQLite. 4197** 4198** The idxNum and idxPtr values are recorded and passed into the 4199** [xFilter] method. 4200** [sqlite3_free()] is used to free idxPtr if and only iff 4201** needToFreeIdxPtr is true. 4202** 4203** The orderByConsumed means that output from [xFilter]/[xNext] will occur in 4204** the correct order to satisfy the ORDER BY clause so that no separate 4205** sorting step is required. 4206** 4207** The estimatedCost value is an estimate of the cost of doing the 4208** particular lookup. A full scan of a table with N entries should have 4209** a cost of N. A binary search of a table of N entries should have a 4210** cost of approximately log(N). 4211*/ 4212struct sqlite3_index_info { 4213 /* Inputs */ 4214 int nConstraint; /* Number of entries in aConstraint */ 4215 struct sqlite3_index_constraint { 4216 int iColumn; /* Column on left-hand side of constraint */ 4217 unsigned char op; /* Constraint operator */ 4218 unsigned char usable; /* True if this constraint is usable */ 4219 int iTermOffset; /* Used internally - xBestIndex should ignore */ 4220 } *aConstraint; /* Table of WHERE clause constraints */ 4221 int nOrderBy; /* Number of terms in the ORDER BY clause */ 4222 struct sqlite3_index_orderby { 4223 int iColumn; /* Column number */ 4224 unsigned char desc; /* True for DESC. False for ASC. */ 4225 } *aOrderBy; /* The ORDER BY clause */ 4226 /* Outputs */ 4227 struct sqlite3_index_constraint_usage { 4228 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 4229 unsigned char omit; /* Do not code a test for this constraint */ 4230 } *aConstraintUsage; 4231 int idxNum; /* Number used to identify the index */ 4232 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 4233 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 4234 int orderByConsumed; /* True if output is already ordered */ 4235 double estimatedCost; /* Estimated cost of using this index */ 4236}; 4237#define SQLITE_INDEX_CONSTRAINT_EQ 2 4238#define SQLITE_INDEX_CONSTRAINT_GT 4 4239#define SQLITE_INDEX_CONSTRAINT_LE 8 4240#define SQLITE_INDEX_CONSTRAINT_LT 16 4241#define SQLITE_INDEX_CONSTRAINT_GE 32 4242#define SQLITE_INDEX_CONSTRAINT_MATCH 64 4243 4244/* 4245** CAPI3REF: Register A Virtual Table Implementation {H18200} <S20400> 4246** EXPERIMENTAL 4247** 4248** This routine is used to register a new [virtual table module] name. 4249** Module names must be registered before 4250** creating a new [virtual table] using the module, or before using a 4251** preexisting [virtual table] for the module. 4252** 4253** The module name is registered on the [database connection] specified 4254** by the first parameter. The name of the module is given by the 4255** second parameter. The third parameter is a pointer to 4256** the implementation of the [virtual table module]. The fourth 4257** parameter is an arbitrary client data pointer that is passed through 4258** into the [xCreate] and [xConnect] methods of the virtual table module 4259** when a new virtual table is be being created or reinitialized. 4260** 4261** This interface has exactly the same effect as calling 4262** [sqlite3_create_module_v2()] with a NULL client data destructor. 4263*/ 4264SQLITE_EXPERIMENTAL int sqlite3_create_module( 4265 sqlite3 *db, /* SQLite connection to register module with */ 4266 const char *zName, /* Name of the module */ 4267 const sqlite3_module *p, /* Methods for the module */ 4268 void *pClientData /* Client data for xCreate/xConnect */ 4269); 4270 4271/* 4272** CAPI3REF: Register A Virtual Table Implementation {H18210} <S20400> 4273** EXPERIMENTAL 4274** 4275** This routine is identical to the [sqlite3_create_module()] method, 4276** except that it has an extra parameter to specify 4277** a destructor function for the client data pointer. SQLite will 4278** invoke the destructor function (if it is not NULL) when SQLite 4279** no longer needs the pClientData pointer. 4280*/ 4281SQLITE_EXPERIMENTAL int sqlite3_create_module_v2( 4282 sqlite3 *db, /* SQLite connection to register module with */ 4283 const char *zName, /* Name of the module */ 4284 const sqlite3_module *p, /* Methods for the module */ 4285 void *pClientData, /* Client data for xCreate/xConnect */ 4286 void(*xDestroy)(void*) /* Module destructor function */ 4287); 4288 4289/* 4290** CAPI3REF: Virtual Table Instance Object {H18010} <S20400> 4291** KEYWORDS: sqlite3_vtab 4292** EXPERIMENTAL 4293** 4294** Every [virtual table module] implementation uses a subclass 4295** of the following structure to describe a particular instance 4296** of the [virtual table]. Each subclass will 4297** be tailored to the specific needs of the module implementation. 4298** The purpose of this superclass is to define certain fields that are 4299** common to all module implementations. 4300** 4301** Virtual tables methods can set an error message by assigning a 4302** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 4303** take care that any prior string is freed by a call to [sqlite3_free()] 4304** prior to assigning a new string to zErrMsg. After the error message 4305** is delivered up to the client application, the string will be automatically 4306** freed by sqlite3_free() and the zErrMsg field will be zeroed. 4307*/ 4308struct sqlite3_vtab { 4309 const sqlite3_module *pModule; /* The module for this virtual table */ 4310 int nRef; /* Used internally */ 4311 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 4312 /* Virtual table implementations will typically add additional fields */ 4313}; 4314 4315/* 4316** CAPI3REF: Virtual Table Cursor Object {H18020} <S20400> 4317** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 4318** EXPERIMENTAL 4319** 4320** Every [virtual table module] implementation uses a subclass of the 4321** following structure to describe cursors that point into the 4322** [virtual table] and are used 4323** to loop through the virtual table. Cursors are created using the 4324** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 4325** by the [sqlite3_module.xClose | xClose] method. Cussors are used 4326** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 4327** of the module. Each module implementation will define 4328** the content of a cursor structure to suit its own needs. 4329** 4330** This superclass exists in order to define fields of the cursor that 4331** are common to all implementations. 4332*/ 4333struct sqlite3_vtab_cursor { 4334 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 4335 /* Virtual table implementations will typically add additional fields */ 4336}; 4337 4338/* 4339** CAPI3REF: Declare The Schema Of A Virtual Table {H18280} <S20400> 4340** EXPERIMENTAL 4341** 4342** The [xCreate] and [xConnect] methods of a 4343** [virtual table module] call this interface 4344** to declare the format (the names and datatypes of the columns) of 4345** the virtual tables they implement. 4346*/ 4347SQLITE_EXPERIMENTAL int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 4348 4349/* 4350** CAPI3REF: Overload A Function For A Virtual Table {H18300} <S20400> 4351** EXPERIMENTAL 4352** 4353** Virtual tables can provide alternative implementations of functions 4354** using the [xFindFunction] method of the [virtual table module]. 4355** But global versions of those functions 4356** must exist in order to be overloaded. 4357** 4358** This API makes sure a global version of a function with a particular 4359** name and number of parameters exists. If no such function exists 4360** before this API is called, a new function is created. The implementation 4361** of the new function always causes an exception to be thrown. So 4362** the new function is not good for anything by itself. Its only 4363** purpose is to be a placeholder function that can be overloaded 4364** by a [virtual table]. 4365*/ 4366SQLITE_EXPERIMENTAL int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 4367 4368/* 4369** The interface to the virtual-table mechanism defined above (back up 4370** to a comment remarkably similar to this one) is currently considered 4371** to be experimental. The interface might change in incompatible ways. 4372** If this is a problem for you, do not use the interface at this time. 4373** 4374** When the virtual-table mechanism stabilizes, we will declare the 4375** interface fixed, support it indefinitely, and remove this comment. 4376** 4377****** EXPERIMENTAL - subject to change without notice ************** 4378*/ 4379 4380/* 4381** CAPI3REF: A Handle To An Open BLOB {H17800} <S30230> 4382** KEYWORDS: {BLOB handle} {BLOB handles} 4383** 4384** An instance of this object represents an open BLOB on which 4385** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 4386** Objects of this type are created by [sqlite3_blob_open()] 4387** and destroyed by [sqlite3_blob_close()]. 4388** The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 4389** can be used to read or write small subsections of the BLOB. 4390** The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 4391*/ 4392typedef struct sqlite3_blob sqlite3_blob; 4393 4394/* 4395** CAPI3REF: Open A BLOB For Incremental I/O {H17810} <S30230> 4396** 4397** This interfaces opens a [BLOB handle | handle] to the BLOB located 4398** in row iRow, column zColumn, table zTable in database zDb; 4399** in other words, the same BLOB that would be selected by: 4400** 4401** <pre> 4402** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 4403** </pre> {END} 4404** 4405** If the flags parameter is non-zero, then the BLOB is opened for read 4406** and write access. If it is zero, the BLOB is opened for read access. 4407** 4408** Note that the database name is not the filename that contains 4409** the database but rather the symbolic name of the database that 4410** is assigned when the database is connected using [ATTACH]. 4411** For the main database file, the database name is "main". 4412** For TEMP tables, the database name is "temp". 4413** 4414** On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 4415** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 4416** to be a null pointer. 4417** This function sets the [database connection] error code and message 4418** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 4419** functions. Note that the *ppBlob variable is always initialized in a 4420** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 4421** regardless of the success or failure of this routine. 4422** 4423** If the row that a BLOB handle points to is modified by an 4424** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 4425** then the BLOB handle is marked as "expired". 4426** This is true if any column of the row is changed, even a column 4427** other than the one the BLOB handle is open on. 4428** Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 4429** a expired BLOB handle fail with an return code of [SQLITE_ABORT]. 4430** Changes written into a BLOB prior to the BLOB expiring are not 4431** rollback by the expiration of the BLOB. Such changes will eventually 4432** commit if the transaction continues to completion. 4433** 4434** Use the [sqlite3_blob_bytes()] interface to determine the size of 4435** the opened blob. The size of a blob may not be changed by this 4436** underface. Use the [UPDATE] SQL command to change the size of a 4437** blob. 4438** 4439** The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 4440** and the built-in [zeroblob] SQL function can be used, if desired, 4441** to create an empty, zero-filled blob in which to read or write using 4442** this interface. 4443** 4444** To avoid a resource leak, every open [BLOB handle] should eventually 4445** be released by a call to [sqlite3_blob_close()]. 4446** 4447** Requirements: 4448** [H17813] [H17814] [H17816] [H17819] [H17821] [H17824] 4449*/ 4450int sqlite3_blob_open( 4451 sqlite3*, 4452 const char *zDb, 4453 const char *zTable, 4454 const char *zColumn, 4455 sqlite3_int64 iRow, 4456 int flags, 4457 sqlite3_blob **ppBlob 4458); 4459 4460/* 4461** CAPI3REF: Close A BLOB Handle {H17830} <S30230> 4462** 4463** Closes an open [BLOB handle]. 4464** 4465** Closing a BLOB shall cause the current transaction to commit 4466** if there are no other BLOBs, no pending prepared statements, and the 4467** database connection is in [autocommit mode]. 4468** If any writes were made to the BLOB, they might be held in cache 4469** until the close operation if they will fit. 4470** 4471** Closing the BLOB often forces the changes 4472** out to disk and so if any I/O errors occur, they will likely occur 4473** at the time when the BLOB is closed. Any errors that occur during 4474** closing are reported as a non-zero return value. 4475** 4476** The BLOB is closed unconditionally. Even if this routine returns 4477** an error code, the BLOB is still closed. 4478** 4479** Calling this routine with a null pointer (which as would be returned 4480** by failed call to [sqlite3_blob_open()]) is a harmless no-op. 4481** 4482** Requirements: 4483** [H17833] [H17836] [H17839] 4484*/ 4485int sqlite3_blob_close(sqlite3_blob *); 4486 4487/* 4488** CAPI3REF: Return The Size Of An Open BLOB {H17840} <S30230> 4489** 4490** Returns the size in bytes of the BLOB accessible via the 4491** successfully opened [BLOB handle] in its only argument. The 4492** incremental blob I/O routines can only read or overwriting existing 4493** blob content; they cannot change the size of a blob. 4494** 4495** This routine only works on a [BLOB handle] which has been created 4496** by a prior successful call to [sqlite3_blob_open()] and which has not 4497** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4498** to this routine results in undefined and probably undesirable behavior. 4499** 4500** Requirements: 4501** [H17843] 4502*/ 4503int sqlite3_blob_bytes(sqlite3_blob *); 4504 4505/* 4506** CAPI3REF: Read Data From A BLOB Incrementally {H17850} <S30230> 4507** 4508** This function is used to read data from an open [BLOB handle] into a 4509** caller-supplied buffer. N bytes of data are copied into buffer Z 4510** from the open BLOB, starting at offset iOffset. 4511** 4512** If offset iOffset is less than N bytes from the end of the BLOB, 4513** [SQLITE_ERROR] is returned and no data is read. If N or iOffset is 4514** less than zero, [SQLITE_ERROR] is returned and no data is read. 4515** The size of the blob (and hence the maximum value of N+iOffset) 4516** can be determined using the [sqlite3_blob_bytes()] interface. 4517** 4518** An attempt to read from an expired [BLOB handle] fails with an 4519** error code of [SQLITE_ABORT]. 4520** 4521** On success, SQLITE_OK is returned. 4522** Otherwise, an [error code] or an [extended error code] is returned. 4523** 4524** This routine only works on a [BLOB handle] which has been created 4525** by a prior successful call to [sqlite3_blob_open()] and which has not 4526** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4527** to this routine results in undefined and probably undesirable behavior. 4528** 4529** See also: [sqlite3_blob_write()]. 4530** 4531** Requirements: 4532** [H17853] [H17856] [H17859] [H17862] [H17863] [H17865] [H17868] 4533*/ 4534int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 4535 4536/* 4537** CAPI3REF: Write Data Into A BLOB Incrementally {H17870} <S30230> 4538** 4539** This function is used to write data into an open [BLOB handle] from a 4540** caller-supplied buffer. N bytes of data are copied from the buffer Z 4541** into the open BLOB, starting at offset iOffset. 4542** 4543** If the [BLOB handle] passed as the first argument was not opened for 4544** writing (the flags parameter to [sqlite3_blob_open()] was zero), 4545** this function returns [SQLITE_READONLY]. 4546** 4547** This function may only modify the contents of the BLOB; it is 4548** not possible to increase the size of a BLOB using this API. 4549** If offset iOffset is less than N bytes from the end of the BLOB, 4550** [SQLITE_ERROR] is returned and no data is written. If N is 4551** less than zero [SQLITE_ERROR] is returned and no data is written. 4552** The size of the BLOB (and hence the maximum value of N+iOffset) 4553** can be determined using the [sqlite3_blob_bytes()] interface. 4554** 4555** An attempt to write to an expired [BLOB handle] fails with an 4556** error code of [SQLITE_ABORT]. Writes to the BLOB that occurred 4557** before the [BLOB handle] expired are not rolled back by the 4558** expiration of the handle, though of course those changes might 4559** have been overwritten by the statement that expired the BLOB handle 4560** or by other independent statements. 4561** 4562** On success, SQLITE_OK is returned. 4563** Otherwise, an [error code] or an [extended error code] is returned. 4564** 4565** This routine only works on a [BLOB handle] which has been created 4566** by a prior successful call to [sqlite3_blob_open()] and which has not 4567** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4568** to this routine results in undefined and probably undesirable behavior. 4569** 4570** See also: [sqlite3_blob_read()]. 4571** 4572** Requirements: 4573** [H17873] [H17874] [H17875] [H17876] [H17877] [H17879] [H17882] [H17885] 4574** [H17888] 4575*/ 4576int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 4577 4578/* 4579** CAPI3REF: Virtual File System Objects {H11200} <S20100> 4580** 4581** A virtual filesystem (VFS) is an [sqlite3_vfs] object 4582** that SQLite uses to interact 4583** with the underlying operating system. Most SQLite builds come with a 4584** single default VFS that is appropriate for the host computer. 4585** New VFSes can be registered and existing VFSes can be unregistered. 4586** The following interfaces are provided. 4587** 4588** The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 4589** Names are case sensitive. 4590** Names are zero-terminated UTF-8 strings. 4591** If there is no match, a NULL pointer is returned. 4592** If zVfsName is NULL then the default VFS is returned. 4593** 4594** New VFSes are registered with sqlite3_vfs_register(). 4595** Each new VFS becomes the default VFS if the makeDflt flag is set. 4596** The same VFS can be registered multiple times without injury. 4597** To make an existing VFS into the default VFS, register it again 4598** with the makeDflt flag set. If two different VFSes with the 4599** same name are registered, the behavior is undefined. If a 4600** VFS is registered with a name that is NULL or an empty string, 4601** then the behavior is undefined. 4602** 4603** Unregister a VFS with the sqlite3_vfs_unregister() interface. 4604** If the default VFS is unregistered, another VFS is chosen as 4605** the default. The choice for the new VFS is arbitrary. 4606** 4607** Requirements: 4608** [H11203] [H11206] [H11209] [H11212] [H11215] [H11218] 4609*/ 4610sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 4611int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 4612int sqlite3_vfs_unregister(sqlite3_vfs*); 4613 4614/* 4615** CAPI3REF: Mutexes {H17000} <S20000> 4616** 4617** The SQLite core uses these routines for thread 4618** synchronization. Though they are intended for internal 4619** use by SQLite, code that links against SQLite is 4620** permitted to use any of these routines. 4621** 4622** The SQLite source code contains multiple implementations 4623** of these mutex routines. An appropriate implementation 4624** is selected automatically at compile-time. The following 4625** implementations are available in the SQLite core: 4626** 4627** <ul> 4628** <li> SQLITE_MUTEX_OS2 4629** <li> SQLITE_MUTEX_PTHREAD 4630** <li> SQLITE_MUTEX_W32 4631** <li> SQLITE_MUTEX_NOOP 4632** </ul> 4633** 4634** The SQLITE_MUTEX_NOOP implementation is a set of routines 4635** that does no real locking and is appropriate for use in 4636** a single-threaded application. The SQLITE_MUTEX_OS2, 4637** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations 4638** are appropriate for use on OS/2, Unix, and Windows. 4639** 4640** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 4641** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 4642** implementation is included with the library. In this case the 4643** application must supply a custom mutex implementation using the 4644** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 4645** before calling sqlite3_initialize() or any other public sqlite3_ 4646** function that calls sqlite3_initialize(). 4647** 4648** {H17011} The sqlite3_mutex_alloc() routine allocates a new 4649** mutex and returns a pointer to it. {H17012} If it returns NULL 4650** that means that a mutex could not be allocated. {H17013} SQLite 4651** will unwind its stack and return an error. {H17014} The argument 4652** to sqlite3_mutex_alloc() is one of these integer constants: 4653** 4654** <ul> 4655** <li> SQLITE_MUTEX_FAST 4656** <li> SQLITE_MUTEX_RECURSIVE 4657** <li> SQLITE_MUTEX_STATIC_MASTER 4658** <li> SQLITE_MUTEX_STATIC_MEM 4659** <li> SQLITE_MUTEX_STATIC_MEM2 4660** <li> SQLITE_MUTEX_STATIC_PRNG 4661** <li> SQLITE_MUTEX_STATIC_LRU 4662** <li> SQLITE_MUTEX_STATIC_LRU2 4663** </ul> 4664** 4665** {H17015} The first two constants cause sqlite3_mutex_alloc() to create 4666** a new mutex. The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 4667** is used but not necessarily so when SQLITE_MUTEX_FAST is used. {END} 4668** The mutex implementation does not need to make a distinction 4669** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 4670** not want to. {H17016} But SQLite will only request a recursive mutex in 4671** cases where it really needs one. {END} If a faster non-recursive mutex 4672** implementation is available on the host platform, the mutex subsystem 4673** might return such a mutex in response to SQLITE_MUTEX_FAST. 4674** 4675** {H17017} The other allowed parameters to sqlite3_mutex_alloc() each return 4676** a pointer to a static preexisting mutex. {END} Four static mutexes are 4677** used by the current version of SQLite. Future versions of SQLite 4678** may add additional static mutexes. Static mutexes are for internal 4679** use by SQLite only. Applications that use SQLite mutexes should 4680** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 4681** SQLITE_MUTEX_RECURSIVE. 4682** 4683** {H17018} Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 4684** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 4685** returns a different mutex on every call. {H17034} But for the static 4686** mutex types, the same mutex is returned on every call that has 4687** the same type number. 4688** 4689** {H17019} The sqlite3_mutex_free() routine deallocates a previously 4690** allocated dynamic mutex. {H17020} SQLite is careful to deallocate every 4691** dynamic mutex that it allocates. {A17021} The dynamic mutexes must not be in 4692** use when they are deallocated. {A17022} Attempting to deallocate a static 4693** mutex results in undefined behavior. {H17023} SQLite never deallocates 4694** a static mutex. {END} 4695** 4696** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 4697** to enter a mutex. {H17024} If another thread is already within the mutex, 4698** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 4699** SQLITE_BUSY. {H17025} The sqlite3_mutex_try() interface returns [SQLITE_OK] 4700** upon successful entry. {H17026} Mutexes created using 4701** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 4702** {H17027} In such cases the, 4703** mutex must be exited an equal number of times before another thread 4704** can enter. {A17028} If the same thread tries to enter any other 4705** kind of mutex more than once, the behavior is undefined. 4706** {H17029} SQLite will never exhibit 4707** such behavior in its own use of mutexes. 4708** 4709** Some systems (for example, Windows 95) do not support the operation 4710** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 4711** will always return SQLITE_BUSY. {H17030} The SQLite core only ever uses 4712** sqlite3_mutex_try() as an optimization so this is acceptable behavior. 4713** 4714** {H17031} The sqlite3_mutex_leave() routine exits a mutex that was 4715** previously entered by the same thread. {A17032} The behavior 4716** is undefined if the mutex is not currently entered by the 4717** calling thread or is not currently allocated. {H17033} SQLite will 4718** never do either. {END} 4719** 4720** If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 4721** sqlite3_mutex_leave() is a NULL pointer, then all three routines 4722** behave as no-ops. 4723** 4724** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 4725*/ 4726sqlite3_mutex *sqlite3_mutex_alloc(int); 4727void sqlite3_mutex_free(sqlite3_mutex*); 4728void sqlite3_mutex_enter(sqlite3_mutex*); 4729int sqlite3_mutex_try(sqlite3_mutex*); 4730void sqlite3_mutex_leave(sqlite3_mutex*); 4731 4732/* 4733** CAPI3REF: Mutex Methods Object {H17120} <S20130> 4734** EXPERIMENTAL 4735** 4736** An instance of this structure defines the low-level routines 4737** used to allocate and use mutexes. 4738** 4739** Usually, the default mutex implementations provided by SQLite are 4740** sufficient, however the user has the option of substituting a custom 4741** implementation for specialized deployments or systems for which SQLite 4742** does not provide a suitable implementation. In this case, the user 4743** creates and populates an instance of this structure to pass 4744** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 4745** Additionally, an instance of this structure can be used as an 4746** output variable when querying the system for the current mutex 4747** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 4748** 4749** The xMutexInit method defined by this structure is invoked as 4750** part of system initialization by the sqlite3_initialize() function. 4751** {H17001} The xMutexInit routine shall be called by SQLite once for each 4752** effective call to [sqlite3_initialize()]. 4753** 4754** The xMutexEnd method defined by this structure is invoked as 4755** part of system shutdown by the sqlite3_shutdown() function. The 4756** implementation of this method is expected to release all outstanding 4757** resources obtained by the mutex methods implementation, especially 4758** those obtained by the xMutexInit method. {H17003} The xMutexEnd() 4759** interface shall be invoked once for each call to [sqlite3_shutdown()]. 4760** 4761** The remaining seven methods defined by this structure (xMutexAlloc, 4762** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 4763** xMutexNotheld) implement the following interfaces (respectively): 4764** 4765** <ul> 4766** <li> [sqlite3_mutex_alloc()] </li> 4767** <li> [sqlite3_mutex_free()] </li> 4768** <li> [sqlite3_mutex_enter()] </li> 4769** <li> [sqlite3_mutex_try()] </li> 4770** <li> [sqlite3_mutex_leave()] </li> 4771** <li> [sqlite3_mutex_held()] </li> 4772** <li> [sqlite3_mutex_notheld()] </li> 4773** </ul> 4774** 4775** The only difference is that the public sqlite3_XXX functions enumerated 4776** above silently ignore any invocations that pass a NULL pointer instead 4777** of a valid mutex handle. The implementations of the methods defined 4778** by this structure are not required to handle this case, the results 4779** of passing a NULL pointer instead of a valid mutex handle are undefined 4780** (i.e. it is acceptable to provide an implementation that segfaults if 4781** it is passed a NULL pointer). 4782*/ 4783typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 4784struct sqlite3_mutex_methods { 4785 int (*xMutexInit)(void); 4786 int (*xMutexEnd)(void); 4787 sqlite3_mutex *(*xMutexAlloc)(int); 4788 void (*xMutexFree)(sqlite3_mutex *); 4789 void (*xMutexEnter)(sqlite3_mutex *); 4790 int (*xMutexTry)(sqlite3_mutex *); 4791 void (*xMutexLeave)(sqlite3_mutex *); 4792 int (*xMutexHeld)(sqlite3_mutex *); 4793 int (*xMutexNotheld)(sqlite3_mutex *); 4794}; 4795 4796/* 4797** CAPI3REF: Mutex Verification Routines {H17080} <S20130> <S30800> 4798** 4799** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 4800** are intended for use inside assert() statements. {H17081} The SQLite core 4801** never uses these routines except inside an assert() and applications 4802** are advised to follow the lead of the core. {H17082} The core only 4803** provides implementations for these routines when it is compiled 4804** with the SQLITE_DEBUG flag. {A17087} External mutex implementations 4805** are only required to provide these routines if SQLITE_DEBUG is 4806** defined and if NDEBUG is not defined. 4807** 4808** {H17083} These routines should return true if the mutex in their argument 4809** is held or not held, respectively, by the calling thread. 4810** 4811** {X17084} The implementation is not required to provided versions of these 4812** routines that actually work. If the implementation does not provide working 4813** versions of these routines, it should at least provide stubs that always 4814** return true so that one does not get spurious assertion failures. 4815** 4816** {H17085} If the argument to sqlite3_mutex_held() is a NULL pointer then 4817** the routine should return 1. {END} This seems counter-intuitive since 4818** clearly the mutex cannot be held if it does not exist. But the 4819** the reason the mutex does not exist is because the build is not 4820** using mutexes. And we do not want the assert() containing the 4821** call to sqlite3_mutex_held() to fail, so a non-zero return is 4822** the appropriate thing to do. {H17086} The sqlite3_mutex_notheld() 4823** interface should also return 1 when given a NULL pointer. 4824*/ 4825int sqlite3_mutex_held(sqlite3_mutex*); 4826int sqlite3_mutex_notheld(sqlite3_mutex*); 4827 4828/* 4829** CAPI3REF: Mutex Types {H17001} <H17000> 4830** 4831** The [sqlite3_mutex_alloc()] interface takes a single argument 4832** which is one of these integer constants. 4833** 4834** The set of static mutexes may change from one SQLite release to the 4835** next. Applications that override the built-in mutex logic must be 4836** prepared to accommodate additional static mutexes. 4837*/ 4838#define SQLITE_MUTEX_FAST 0 4839#define SQLITE_MUTEX_RECURSIVE 1 4840#define SQLITE_MUTEX_STATIC_MASTER 2 4841#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 4842#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 4843#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 4844#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 4845#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 4846#define SQLITE_MUTEX_STATIC_LRU2 7 /* lru page list */ 4847 4848/* 4849** CAPI3REF: Retrieve the mutex for a database connection {H17002} <H17000> 4850** 4851** This interface returns a pointer the [sqlite3_mutex] object that 4852** serializes access to the [database connection] given in the argument 4853** when the [threading mode] is Serialized. 4854** If the [threading mode] is Single-thread or Multi-thread then this 4855** routine returns a NULL pointer. 4856*/ 4857sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 4858 4859/* 4860** CAPI3REF: Low-Level Control Of Database Files {H11300} <S30800> 4861** 4862** {H11301} The [sqlite3_file_control()] interface makes a direct call to the 4863** xFileControl method for the [sqlite3_io_methods] object associated 4864** with a particular database identified by the second argument. {H11302} The 4865** name of the database is the name assigned to the database by the 4866** <a href="lang_attach.html">ATTACH</a> SQL command that opened the 4867** database. {H11303} To control the main database file, use the name "main" 4868** or a NULL pointer. {H11304} The third and fourth parameters to this routine 4869** are passed directly through to the second and third parameters of 4870** the xFileControl method. {H11305} The return value of the xFileControl 4871** method becomes the return value of this routine. 4872** 4873** {H11306} If the second parameter (zDbName) does not match the name of any 4874** open database file, then SQLITE_ERROR is returned. {H11307} This error 4875** code is not remembered and will not be recalled by [sqlite3_errcode()] 4876** or [sqlite3_errmsg()]. {A11308} The underlying xFileControl method might 4877** also return SQLITE_ERROR. {A11309} There is no way to distinguish between 4878** an incorrect zDbName and an SQLITE_ERROR return from the underlying 4879** xFileControl method. {END} 4880** 4881** See also: [SQLITE_FCNTL_LOCKSTATE] 4882*/ 4883int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 4884 4885/* 4886** CAPI3REF: Testing Interface {H11400} <S30800> 4887** 4888** The sqlite3_test_control() interface is used to read out internal 4889** state of SQLite and to inject faults into SQLite for testing 4890** purposes. The first parameter is an operation code that determines 4891** the number, meaning, and operation of all subsequent parameters. 4892** 4893** This interface is not for use by applications. It exists solely 4894** for verifying the correct operation of the SQLite library. Depending 4895** on how the SQLite library is compiled, this interface might not exist. 4896** 4897** The details of the operation codes, their meanings, the parameters 4898** they take, and what they do are all subject to change without notice. 4899** Unlike most of the SQLite API, this function is not guaranteed to 4900** operate consistently from one release to the next. 4901*/ 4902int sqlite3_test_control(int op, ...); 4903 4904/* 4905** CAPI3REF: Testing Interface Operation Codes {H11410} <H11400> 4906** 4907** These constants are the valid operation code parameters used 4908** as the first argument to [sqlite3_test_control()]. 4909** 4910** These parameters and their meanings are subject to change 4911** without notice. These values are for testing purposes only. 4912** Applications should not use any of these parameters or the 4913** [sqlite3_test_control()] interface. 4914*/ 4915#define SQLITE_TESTCTRL_PRNG_SAVE 5 4916#define SQLITE_TESTCTRL_PRNG_RESTORE 6 4917#define SQLITE_TESTCTRL_PRNG_RESET 7 4918#define SQLITE_TESTCTRL_BITVEC_TEST 8 4919#define SQLITE_TESTCTRL_FAULT_INSTALL 9 4920#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 4921#define SQLITE_TESTCTRL_PENDING_BYTE 11 4922#define SQLITE_TESTCTRL_ASSERT 12 4923#define SQLITE_TESTCTRL_ALWAYS 13 4924 4925/* 4926** CAPI3REF: SQLite Runtime Status {H17200} <S60200> 4927** EXPERIMENTAL 4928** 4929** This interface is used to retrieve runtime status information 4930** about the preformance of SQLite, and optionally to reset various 4931** highwater marks. The first argument is an integer code for 4932** the specific parameter to measure. Recognized integer codes 4933** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...]. 4934** The current value of the parameter is returned into *pCurrent. 4935** The highest recorded value is returned in *pHighwater. If the 4936** resetFlag is true, then the highest record value is reset after 4937** *pHighwater is written. Some parameters do not record the highest 4938** value. For those parameters 4939** nothing is written into *pHighwater and the resetFlag is ignored. 4940** Other parameters record only the highwater mark and not the current 4941** value. For these latter parameters nothing is written into *pCurrent. 4942** 4943** This routine returns SQLITE_OK on success and a non-zero 4944** [error code] on failure. 4945** 4946** This routine is threadsafe but is not atomic. This routine can 4947** called while other threads are running the same or different SQLite 4948** interfaces. However the values returned in *pCurrent and 4949** *pHighwater reflect the status of SQLite at different points in time 4950** and it is possible that another thread might change the parameter 4951** in between the times when *pCurrent and *pHighwater are written. 4952** 4953** See also: [sqlite3_db_status()] 4954*/ 4955SQLITE_EXPERIMENTAL int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 4956 4957 4958/* 4959** CAPI3REF: Status Parameters {H17250} <H17200> 4960** EXPERIMENTAL 4961** 4962** These integer constants designate various run-time status parameters 4963** that can be returned by [sqlite3_status()]. 4964** 4965** <dl> 4966** <dt>SQLITE_STATUS_MEMORY_USED</dt> 4967** <dd>This parameter is the current amount of memory checked out 4968** using [sqlite3_malloc()], either directly or indirectly. The 4969** figure includes calls made to [sqlite3_malloc()] by the application 4970** and internal memory usage by the SQLite library. Scratch memory 4971** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 4972** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 4973** this parameter. The amount returned is the sum of the allocation 4974** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd> 4975** 4976** <dt>SQLITE_STATUS_MALLOC_SIZE</dt> 4977** <dd>This parameter records the largest memory allocation request 4978** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 4979** internal equivalents). Only the value returned in the 4980** *pHighwater parameter to [sqlite3_status()] is of interest. 4981** The value written into the *pCurrent parameter is undefined.</dd> 4982** 4983** <dt>SQLITE_STATUS_PAGECACHE_USED</dt> 4984** <dd>This parameter returns the number of pages used out of the 4985** [pagecache memory allocator] that was configured using 4986** [SQLITE_CONFIG_PAGECACHE]. The 4987** value returned is in pages, not in bytes.</dd> 4988** 4989** <dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 4990** <dd>This parameter returns the number of bytes of page cache 4991** allocation which could not be statisfied by the [SQLITE_CONFIG_PAGECACHE] 4992** buffer and where forced to overflow to [sqlite3_malloc()]. The 4993** returned value includes allocations that overflowed because they 4994** where too large (they were larger than the "sz" parameter to 4995** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 4996** no space was left in the page cache.</dd> 4997** 4998** <dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 4999** <dd>This parameter records the largest memory allocation request 5000** handed to [pagecache memory allocator]. Only the value returned in the 5001** *pHighwater parameter to [sqlite3_status()] is of interest. 5002** The value written into the *pCurrent parameter is undefined.</dd> 5003** 5004** <dt>SQLITE_STATUS_SCRATCH_USED</dt> 5005** <dd>This parameter returns the number of allocations used out of the 5006** [scratch memory allocator] configured using 5007** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5008** in bytes. Since a single thread may only have one scratch allocation 5009** outstanding at time, this parameter also reports the number of threads 5010** using scratch memory at the same time.</dd> 5011** 5012** <dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5013** <dd>This parameter returns the number of bytes of scratch memory 5014** allocation which could not be statisfied by the [SQLITE_CONFIG_SCRATCH] 5015** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5016** returned include overflows because the requested allocation was too 5017** larger (that is, because the requested allocation was larger than the 5018** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5019** slots were available. 5020** </dd> 5021** 5022** <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5023** <dd>This parameter records the largest memory allocation request 5024** handed to [scratch memory allocator]. Only the value returned in the 5025** *pHighwater parameter to [sqlite3_status()] is of interest. 5026** The value written into the *pCurrent parameter is undefined.</dd> 5027** 5028** <dt>SQLITE_STATUS_PARSER_STACK</dt> 5029** <dd>This parameter records the deepest parser stack. It is only 5030** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd> 5031** </dl> 5032** 5033** New status parameters may be added from time to time. 5034*/ 5035#define SQLITE_STATUS_MEMORY_USED 0 5036#define SQLITE_STATUS_PAGECACHE_USED 1 5037#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5038#define SQLITE_STATUS_SCRATCH_USED 3 5039#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5040#define SQLITE_STATUS_MALLOC_SIZE 5 5041#define SQLITE_STATUS_PARSER_STACK 6 5042#define SQLITE_STATUS_PAGECACHE_SIZE 7 5043#define SQLITE_STATUS_SCRATCH_SIZE 8 5044 5045/* 5046** CAPI3REF: Database Connection Status {H17500} <S60200> 5047** EXPERIMENTAL 5048** 5049** This interface is used to retrieve runtime status information 5050** about a single [database connection]. The first argument is the 5051** database connection object to be interrogated. The second argument 5052** is the parameter to interrogate. Currently, the only allowed value 5053** for the second parameter is [SQLITE_DBSTATUS_LOOKASIDE_USED]. 5054** Additional options will likely appear in future releases of SQLite. 5055** 5056** The current value of the requested parameter is written into *pCur 5057** and the highest instantaneous value is written into *pHiwtr. If 5058** the resetFlg is true, then the highest instantaneous value is 5059** reset back down to the current value. 5060** 5061** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5062*/ 5063SQLITE_EXPERIMENTAL int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5064 5065/* 5066** CAPI3REF: Status Parameters for database connections {H17520} <H17500> 5067** EXPERIMENTAL 5068** 5069** Status verbs for [sqlite3_db_status()]. 5070** 5071** <dl> 5072** <dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5073** <dd>This parameter returns the number of lookaside memory slots currently 5074** checked out.</dd> 5075** </dl> 5076*/ 5077#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 5078 5079 5080/* 5081** CAPI3REF: Prepared Statement Status {H17550} <S60200> 5082** EXPERIMENTAL 5083** 5084** Each prepared statement maintains various 5085** [SQLITE_STMTSTATUS_SORT | counters] that measure the number 5086** of times it has performed specific operations. These counters can 5087** be used to monitor the performance characteristics of the prepared 5088** statements. For example, if the number of table steps greatly exceeds 5089** the number of table searches or result rows, that would tend to indicate 5090** that the prepared statement is using a full table scan rather than 5091** an index. 5092** 5093** This interface is used to retrieve and reset counter values from 5094** a [prepared statement]. The first argument is the prepared statement 5095** object to be interrogated. The second argument 5096** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter] 5097** to be interrogated. 5098** The current value of the requested counter is returned. 5099** If the resetFlg is true, then the counter is reset to zero after this 5100** interface call returns. 5101** 5102** See also: [sqlite3_status()] and [sqlite3_db_status()]. 5103*/ 5104SQLITE_EXPERIMENTAL int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 5105 5106/* 5107** CAPI3REF: Status Parameters for prepared statements {H17570} <H17550> 5108** EXPERIMENTAL 5109** 5110** These preprocessor macros define integer codes that name counter 5111** values associated with the [sqlite3_stmt_status()] interface. 5112** The meanings of the various counters are as follows: 5113** 5114** <dl> 5115** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 5116** <dd>This is the number of times that SQLite has stepped forward in 5117** a table as part of a full table scan. Large numbers for this counter 5118** may indicate opportunities for performance improvement through 5119** careful use of indices.</dd> 5120** 5121** <dt>SQLITE_STMTSTATUS_SORT</dt> 5122** <dd>This is the number of sort operations that have occurred. 5123** A non-zero value in this counter may indicate an opportunity to 5124** improvement performance through careful use of indices.</dd> 5125** 5126** </dl> 5127*/ 5128#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 5129#define SQLITE_STMTSTATUS_SORT 2 5130 5131/* 5132** CAPI3REF: Custom Page Cache Object 5133** EXPERIMENTAL 5134** 5135** The sqlite3_pcache type is opaque. It is implemented by 5136** the pluggable module. The SQLite core has no knowledge of 5137** its size or internal structure and never deals with the 5138** sqlite3_pcache object except by holding and passing pointers 5139** to the object. 5140** 5141** See [sqlite3_pcache_methods] for additional information. 5142*/ 5143typedef struct sqlite3_pcache sqlite3_pcache; 5144 5145/* 5146** CAPI3REF: Application Defined Page Cache. 5147** EXPERIMENTAL 5148** 5149** The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can 5150** register an alternative page cache implementation by passing in an 5151** instance of the sqlite3_pcache_methods structure. The majority of the 5152** heap memory used by sqlite is used by the page cache to cache data read 5153** from, or ready to be written to, the database file. By implementing a 5154** custom page cache using this API, an application can control more 5155** precisely the amount of memory consumed by sqlite, the way in which 5156** said memory is allocated and released, and the policies used to 5157** determine exactly which parts of a database file are cached and for 5158** how long. 5159** 5160** The contents of the structure are copied to an internal buffer by sqlite 5161** within the call to [sqlite3_config]. 5162** 5163** The xInit() method is called once for each call to [sqlite3_initialize()] 5164** (usually only once during the lifetime of the process). It is passed 5165** a copy of the sqlite3_pcache_methods.pArg value. It can be used to set 5166** up global structures and mutexes required by the custom page cache 5167** implementation. The xShutdown() method is called from within 5168** [sqlite3_shutdown()], if the application invokes this API. It can be used 5169** to clean up any outstanding resources before process shutdown, if required. 5170** 5171** The xCreate() method is used to construct a new cache instance. The 5172** first parameter, szPage, is the size in bytes of the pages that must 5173** be allocated by the cache. szPage will not be a power of two. The 5174** second argument, bPurgeable, is true if the cache being created will 5175** be used to cache database pages read from a file stored on disk, or 5176** false if it is used for an in-memory database. The cache implementation 5177** does not have to do anything special based on the value of bPurgeable, 5178** it is purely advisory. 5179** 5180** The xCachesize() method may be called at any time by SQLite to set the 5181** suggested maximum cache-size (number of pages stored by) the cache 5182** instance passed as the first argument. This is the value configured using 5183** the SQLite "[PRAGMA cache_size]" command. As with the bPurgeable parameter, 5184** the implementation is not required to do anything special with this 5185** value, it is advisory only. 5186** 5187** The xPagecount() method should return the number of pages currently 5188** stored in the cache supplied as an argument. 5189** 5190** The xFetch() method is used to fetch a page and return a pointer to it. 5191** A 'page', in this context, is a buffer of szPage bytes aligned at an 5192** 8-byte boundary. The page to be fetched is determined by the key. The 5193** mimimum key value is 1. After it has been retrieved using xFetch, the page 5194** is considered to be pinned. 5195** 5196** If the requested page is already in the page cache, then a pointer to 5197** the cached buffer should be returned with its contents intact. If the 5198** page is not already in the cache, then the expected behaviour of the 5199** cache is determined by the value of the createFlag parameter passed 5200** to xFetch, according to the following table: 5201** 5202** <table border=1 width=85% align=center> 5203** <tr><th>createFlag<th>Expected Behaviour 5204** <tr><td>0<td>NULL should be returned. No new cache entry is created. 5205** <tr><td>1<td>If createFlag is set to 1, this indicates that 5206** SQLite is holding pinned pages that can be unpinned 5207** by writing their contents to the database file (a 5208** relatively expensive operation). In this situation the 5209** cache implementation has two choices: it can return NULL, 5210** in which case SQLite will attempt to unpin one or more 5211** pages before re-requesting the same page, or it can 5212** allocate a new page and return a pointer to it. If a new 5213** page is allocated, then the first sizeof(void*) bytes of 5214** it (at least) must be zeroed before it is returned. 5215** <tr><td>2<td>If createFlag is set to 2, then SQLite is not holding any 5216** pinned pages associated with the specific cache passed 5217** as the first argument to xFetch() that can be unpinned. The 5218** cache implementation should attempt to allocate a new 5219** cache entry and return a pointer to it. Again, the first 5220** sizeof(void*) bytes of the page should be zeroed before 5221** it is returned. If the xFetch() method returns NULL when 5222** createFlag==2, SQLite assumes that a memory allocation 5223** failed and returns SQLITE_NOMEM to the user. 5224** </table> 5225** 5226** xUnpin() is called by SQLite with a pointer to a currently pinned page 5227** as its second argument. If the third parameter, discard, is non-zero, 5228** then the page should be evicted from the cache. In this case SQLite 5229** assumes that the next time the page is retrieved from the cache using 5230** the xFetch() method, it will be zeroed. If the discard parameter is 5231** zero, then the page is considered to be unpinned. The cache implementation 5232** may choose to reclaim (free or recycle) unpinned pages at any time. 5233** SQLite assumes that next time the page is retrieved from the cache 5234** it will either be zeroed, or contain the same data that it did when it 5235** was unpinned. 5236** 5237** The cache is not required to perform any reference counting. A single 5238** call to xUnpin() unpins the page regardless of the number of prior calls 5239** to xFetch(). 5240** 5241** The xRekey() method is used to change the key value associated with the 5242** page passed as the second argument from oldKey to newKey. If the cache 5243** previously contains an entry associated with newKey, it should be 5244** discarded. Any prior cache entry associated with newKey is guaranteed not 5245** to be pinned. 5246** 5247** When SQLite calls the xTruncate() method, the cache must discard all 5248** existing cache entries with page numbers (keys) greater than or equal 5249** to the value of the iLimit parameter passed to xTruncate(). If any 5250** of these pages are pinned, they are implicitly unpinned, meaning that 5251** they can be safely discarded. 5252** 5253** The xDestroy() method is used to delete a cache allocated by xCreate(). 5254** All resources associated with the specified cache should be freed. After 5255** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 5256** handle invalid, and will not use it with any other sqlite3_pcache_methods 5257** functions. 5258*/ 5259typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 5260struct sqlite3_pcache_methods { 5261 void *pArg; 5262 int (*xInit)(void*); 5263 void (*xShutdown)(void*); 5264 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 5265 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 5266 int (*xPagecount)(sqlite3_pcache*); 5267 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 5268 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 5269 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 5270 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 5271 void (*xDestroy)(sqlite3_pcache*); 5272}; 5273 5274/* 5275** CAPI3REF: Online Backup Object 5276** EXPERIMENTAL 5277** 5278** The sqlite3_backup object records state information about an ongoing 5279** online backup operation. The sqlite3_backup object is created by 5280** a call to [sqlite3_backup_init()] and is destroyed by a call to 5281** [sqlite3_backup_finish()]. 5282** 5283** See Also: [Using the SQLite Online Backup API] 5284*/ 5285typedef struct sqlite3_backup sqlite3_backup; 5286 5287/* 5288** CAPI3REF: Online Backup API. 5289** EXPERIMENTAL 5290** 5291** This API is used to overwrite the contents of one database with that 5292** of another. It is useful either for creating backups of databases or 5293** for copying in-memory databases to or from persistent files. 5294** 5295** See Also: [Using the SQLite Online Backup API] 5296** 5297** Exclusive access is required to the destination database for the 5298** duration of the operation. However the source database is only 5299** read-locked while it is actually being read, it is not locked 5300** continuously for the entire operation. Thus, the backup may be 5301** performed on a live database without preventing other users from 5302** writing to the database for an extended period of time. 5303** 5304** To perform a backup operation: 5305** <ol> 5306** <li><b>sqlite3_backup_init()</b> is called once to initialize the 5307** backup, 5308** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 5309** the data between the two databases, and finally 5310** <li><b>sqlite3_backup_finish()</b> is called to release all resources 5311** associated with the backup operation. 5312** </ol> 5313** There should be exactly one call to sqlite3_backup_finish() for each 5314** successful call to sqlite3_backup_init(). 5315** 5316** <b>sqlite3_backup_init()</b> 5317** 5318** The first two arguments passed to [sqlite3_backup_init()] are the database 5319** handle associated with the destination database and the database name 5320** used to attach the destination database to the handle. The database name 5321** is "main" for the main database, "temp" for the temporary database, or 5322** the name specified as part of the [ATTACH] statement if the destination is 5323** an attached database. The third and fourth arguments passed to 5324** sqlite3_backup_init() identify the [database connection] 5325** and database name used 5326** to access the source database. The values passed for the source and 5327** destination [database connection] parameters must not be the same. 5328** 5329** If an error occurs within sqlite3_backup_init(), then NULL is returned 5330** and an error code and error message written into the [database connection] 5331** passed as the first argument. They may be retrieved using the 5332** [sqlite3_errcode()], [sqlite3_errmsg()], and [sqlite3_errmsg16()] functions. 5333** Otherwise, if successful, a pointer to an [sqlite3_backup] object is 5334** returned. This pointer may be used with the sqlite3_backup_step() and 5335** sqlite3_backup_finish() functions to perform the specified backup 5336** operation. 5337** 5338** <b>sqlite3_backup_step()</b> 5339** 5340** Function [sqlite3_backup_step()] is used to copy up to nPage pages between 5341** the source and destination databases, where nPage is the value of the 5342** second parameter passed to sqlite3_backup_step(). If nPage is a negative 5343** value, all remaining source pages are copied. If the required pages are 5344** succesfully copied, but there are still more pages to copy before the 5345** backup is complete, it returns [SQLITE_OK]. If no error occured and there 5346** are no more pages to copy, then [SQLITE_DONE] is returned. If an error 5347** occurs, then an SQLite error code is returned. As well as [SQLITE_OK] and 5348** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 5349** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 5350** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 5351** 5352** As well as the case where the destination database file was opened for 5353** read-only access, sqlite3_backup_step() may return [SQLITE_READONLY] if 5354** the destination is an in-memory database with a different page size 5355** from the source database. 5356** 5357** If sqlite3_backup_step() cannot obtain a required file-system lock, then 5358** the [sqlite3_busy_handler | busy-handler function] 5359** is invoked (if one is specified). If the 5360** busy-handler returns non-zero before the lock is available, then 5361** [SQLITE_BUSY] is returned to the caller. In this case the call to 5362** sqlite3_backup_step() can be retried later. If the source 5363** [database connection] 5364** is being used to write to the source database when sqlite3_backup_step() 5365** is called, then [SQLITE_LOCKED] is returned immediately. Again, in this 5366** case the call to sqlite3_backup_step() can be retried later on. If 5367** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 5368** [SQLITE_READONLY] is returned, then 5369** there is no point in retrying the call to sqlite3_backup_step(). These 5370** errors are considered fatal. At this point the application must accept 5371** that the backup operation has failed and pass the backup operation handle 5372** to the sqlite3_backup_finish() to release associated resources. 5373** 5374** Following the first call to sqlite3_backup_step(), an exclusive lock is 5375** obtained on the destination file. It is not released until either 5376** sqlite3_backup_finish() is called or the backup operation is complete 5377** and sqlite3_backup_step() returns [SQLITE_DONE]. Additionally, each time 5378** a call to sqlite3_backup_step() is made a [shared lock] is obtained on 5379** the source database file. This lock is released before the 5380** sqlite3_backup_step() call returns. Because the source database is not 5381** locked between calls to sqlite3_backup_step(), it may be modified mid-way 5382** through the backup procedure. If the source database is modified by an 5383** external process or via a database connection other than the one being 5384** used by the backup operation, then the backup will be transparently 5385** restarted by the next call to sqlite3_backup_step(). If the source 5386** database is modified by the using the same database connection as is used 5387** by the backup operation, then the backup database is transparently 5388** updated at the same time. 5389** 5390** <b>sqlite3_backup_finish()</b> 5391** 5392** Once sqlite3_backup_step() has returned [SQLITE_DONE], or when the 5393** application wishes to abandon the backup operation, the [sqlite3_backup] 5394** object should be passed to sqlite3_backup_finish(). This releases all 5395** resources associated with the backup operation. If sqlite3_backup_step() 5396** has not yet returned [SQLITE_DONE], then any active write-transaction on the 5397** destination database is rolled back. The [sqlite3_backup] object is invalid 5398** and may not be used following a call to sqlite3_backup_finish(). 5399** 5400** The value returned by sqlite3_backup_finish is [SQLITE_OK] if no error 5401** occurred, regardless or whether or not sqlite3_backup_step() was called 5402** a sufficient number of times to complete the backup operation. Or, if 5403** an out-of-memory condition or IO error occured during a call to 5404** sqlite3_backup_step() then [SQLITE_NOMEM] or an 5405** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] error code 5406** is returned. In this case the error code and an error message are 5407** written to the destination [database connection]. 5408** 5409** A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() is 5410** not a permanent error and does not affect the return value of 5411** sqlite3_backup_finish(). 5412** 5413** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b> 5414** 5415** Each call to sqlite3_backup_step() sets two values stored internally 5416** by an [sqlite3_backup] object. The number of pages still to be backed 5417** up, which may be queried by sqlite3_backup_remaining(), and the total 5418** number of pages in the source database file, which may be queried by 5419** sqlite3_backup_pagecount(). 5420** 5421** The values returned by these functions are only updated by 5422** sqlite3_backup_step(). If the source database is modified during a backup 5423** operation, then the values are not updated to account for any extra 5424** pages that need to be updated or the size of the source database file 5425** changing. 5426** 5427** <b>Concurrent Usage of Database Handles</b> 5428** 5429** The source [database connection] may be used by the application for other 5430** purposes while a backup operation is underway or being initialized. 5431** If SQLite is compiled and configured to support threadsafe database 5432** connections, then the source database connection may be used concurrently 5433** from within other threads. 5434** 5435** However, the application must guarantee that the destination database 5436** connection handle is not passed to any other API (by any thread) after 5437** sqlite3_backup_init() is called and before the corresponding call to 5438** sqlite3_backup_finish(). Unfortunately SQLite does not currently check 5439** for this, if the application does use the destination [database connection] 5440** for some other purpose during a backup operation, things may appear to 5441** work correctly but in fact be subtly malfunctioning. Use of the 5442** destination database connection while a backup is in progress might 5443** also cause a mutex deadlock. 5444** 5445** Furthermore, if running in [shared cache mode], the application must 5446** guarantee that the shared cache used by the destination database 5447** is not accessed while the backup is running. In practice this means 5448** that the application must guarantee that the file-system file being 5449** backed up to is not accessed by any connection within the process, 5450** not just the specific connection that was passed to sqlite3_backup_init(). 5451** 5452** The [sqlite3_backup] object itself is partially threadsafe. Multiple 5453** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 5454** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 5455** APIs are not strictly speaking threadsafe. If they are invoked at the 5456** same time as another thread is invoking sqlite3_backup_step() it is 5457** possible that they return invalid values. 5458*/ 5459sqlite3_backup *sqlite3_backup_init( 5460 sqlite3 *pDest, /* Destination database handle */ 5461 const char *zDestName, /* Destination database name */ 5462 sqlite3 *pSource, /* Source database handle */ 5463 const char *zSourceName /* Source database name */ 5464); 5465int sqlite3_backup_step(sqlite3_backup *p, int nPage); 5466int sqlite3_backup_finish(sqlite3_backup *p); 5467int sqlite3_backup_remaining(sqlite3_backup *p); 5468int sqlite3_backup_pagecount(sqlite3_backup *p); 5469 5470/* 5471** CAPI3REF: Unlock Notification 5472** EXPERIMENTAL 5473** 5474** When running in shared-cache mode, a database operation may fail with 5475** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 5476** individual tables within the shared-cache cannot be obtained. See 5477** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 5478** This API may be used to register a callback that SQLite will invoke 5479** when the connection currently holding the required lock relinquishes it. 5480** This API is only available if the library was compiled with the 5481** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 5482** 5483** See Also: [Using the SQLite Unlock Notification Feature]. 5484** 5485** Shared-cache locks are released when a database connection concludes 5486** its current transaction, either by committing it or rolling it back. 5487** 5488** When a connection (known as the blocked connection) fails to obtain a 5489** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 5490** identity of the database connection (the blocking connection) that 5491** has locked the required resource is stored internally. After an 5492** application receives an SQLITE_LOCKED error, it may call the 5493** sqlite3_unlock_notify() method with the blocked connection handle as 5494** the first argument to register for a callback that will be invoked 5495** when the blocking connections current transaction is concluded. The 5496** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 5497** call that concludes the blocking connections transaction. 5498** 5499** If sqlite3_unlock_notify() is called in a multi-threaded application, 5500** there is a chance that the blocking connection will have already 5501** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 5502** If this happens, then the specified callback is invoked immediately, 5503** from within the call to sqlite3_unlock_notify(). 5504** 5505** If the blocked connection is attempting to obtain a write-lock on a 5506** shared-cache table, and more than one other connection currently holds 5507** a read-lock on the same table, then SQLite arbitrarily selects one of 5508** the other connections to use as the blocking connection. 5509** 5510** There may be at most one unlock-notify callback registered by a 5511** blocked connection. If sqlite3_unlock_notify() is called when the 5512** blocked connection already has a registered unlock-notify callback, 5513** then the new callback replaces the old. If sqlite3_unlock_notify() is 5514** called with a NULL pointer as its second argument, then any existing 5515** unlock-notify callback is cancelled. The blocked connections 5516** unlock-notify callback may also be canceled by closing the blocked 5517** connection using [sqlite3_close()]. 5518** 5519** The unlock-notify callback is not reentrant. If an application invokes 5520** any sqlite3_xxx API functions from within an unlock-notify callback, a 5521** crash or deadlock may be the result. 5522** 5523** Unless deadlock is detected (see below), sqlite3_unlock_notify() always 5524** returns SQLITE_OK. 5525** 5526** <b>Callback Invocation Details</b> 5527** 5528** When an unlock-notify callback is registered, the application provides a 5529** single void* pointer that is passed to the callback when it is invoked. 5530** However, the signature of the callback function allows SQLite to pass 5531** it an array of void* context pointers. The first argument passed to 5532** an unlock-notify callback is a pointer to an array of void* pointers, 5533** and the second is the number of entries in the array. 5534** 5535** When a blocking connections transaction is concluded, there may be 5536** more than one blocked connection that has registered for an unlock-notify 5537** callback. If two or more such blocked connections have specified the 5538** same callback function, then instead of invoking the callback function 5539** multiple times, it is invoked once with the set of void* context pointers 5540** specified by the blocked connections bundled together into an array. 5541** This gives the application an opportunity to prioritize any actions 5542** related to the set of unblocked database connections. 5543** 5544** <b>Deadlock Detection</b> 5545** 5546** Assuming that after registering for an unlock-notify callback a 5547** database waits for the callback to be issued before taking any further 5548** action (a reasonable assumption), then using this API may cause the 5549** application to deadlock. For example, if connection X is waiting for 5550** connection Y's transaction to be concluded, and similarly connection 5551** Y is waiting on connection X's transaction, then neither connection 5552** will proceed and the system may remain deadlocked indefinitely. 5553** 5554** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 5555** detection. If a given call to sqlite3_unlock_notify() would put the 5556** system in a deadlocked state, then SQLITE_LOCKED is returned and no 5557** unlock-notify callback is registered. The system is said to be in 5558** a deadlocked state if connection A has registered for an unlock-notify 5559** callback on the conclusion of connection B's transaction, and connection 5560** B has itself registered for an unlock-notify callback when connection 5561** A's transaction is concluded. Indirect deadlock is also detected, so 5562** the system is also considered to be deadlocked if connection B has 5563** registered for an unlock-notify callback on the conclusion of connection 5564** C's transaction, where connection C is waiting on connection A. Any 5565** number of levels of indirection are allowed. 5566** 5567** <b>The "DROP TABLE" Exception</b> 5568** 5569** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 5570** always appropriate to call sqlite3_unlock_notify(). There is however, 5571** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 5572** SQLite checks if there are any currently executing SELECT statements 5573** that belong to the same connection. If there are, SQLITE_LOCKED is 5574** returned. In this case there is no "blocking connection", so invoking 5575** sqlite3_unlock_notify() results in the unlock-notify callback being 5576** invoked immediately. If the application then re-attempts the "DROP TABLE" 5577** or "DROP INDEX" query, an infinite loop might be the result. 5578** 5579** One way around this problem is to check the extended error code returned 5580** by an sqlite3_step() call. If there is a blocking connection, then the 5581** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 5582** the special "DROP TABLE/INDEX" case, the extended error code is just 5583** SQLITE_LOCKED. 5584*/ 5585int sqlite3_unlock_notify( 5586 sqlite3 *pBlocked, /* Waiting connection */ 5587 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 5588 void *pNotifyArg /* Argument to pass to xNotify */ 5589); 5590 5591/* 5592** Undo the hack that converts floating point types to integer for 5593** builds on processors without floating point support. 5594*/ 5595#ifdef SQLITE_OMIT_FLOATING_POINT 5596# undef double 5597#endif 5598 5599#ifdef __cplusplus 5600} /* End of the 'extern "C"' block */ 5601#endif 5602#endif 5603