1/* 2** 2001 September 15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are suppose to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef _SQLITE3_H_ 34#define _SQLITE3_H_ 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Add the ability to override 'extern' 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51 52/* 53** These no-op macros are used in front of interfaces to mark those 54** interfaces as either deprecated or experimental. New applications 55** should not use deprecated interfaces - they are support for backwards 56** compatibility only. Application writers should be aware that 57** experimental interfaces are subject to change in point releases. 58** 59** These macros used to resolve to various kinds of compiler magic that 60** would generate warning messages when they were used. But that 61** compiler magic ended up generating such a flurry of bug reports 62** that we have taken it all out and gone back to using simple 63** noop macros. 64*/ 65#define SQLITE_DEPRECATED 66#define SQLITE_EXPERIMENTAL 67 68/* 69** Ensure these symbols were not defined by some previous header file. 70*/ 71#ifdef SQLITE_VERSION 72# undef SQLITE_VERSION 73#endif 74#ifdef SQLITE_VERSION_NUMBER 75# undef SQLITE_VERSION_NUMBER 76#endif 77 78/* 79** CAPI3REF: Compile-Time Library Version Numbers {H10010} <S60100> 80** 81** The SQLITE_VERSION and SQLITE_VERSION_NUMBER #defines in 82** the sqlite3.h file specify the version of SQLite with which 83** that header file is associated. 84** 85** The "version" of SQLite is a string of the form "W.X.Y" or "W.X.Y.Z". 86** The W value is major version number and is always 3 in SQLite3. 87** The W value only changes when backwards compatibility is 88** broken and we intend to never break backwards compatibility. 89** The X value is the minor version number and only changes when 90** there are major feature enhancements that are forwards compatible 91** but not backwards compatible. 92** The Y value is the release number and is incremented with 93** each release but resets back to 0 whenever X is incremented. 94** The Z value only appears on branch releases. 95** 96** The SQLITE_VERSION_NUMBER is an integer that is computed as 97** follows: 98** 99** <blockquote><pre> 100** SQLITE_VERSION_NUMBER = W*1000000 + X*1000 + Y 101** </pre></blockquote> 102** 103** Since version 3.6.18, SQLite source code has been stored in the 104** <a href="http://www.fossil-scm.org/">fossil configuration management 105** system</a>. The SQLITE_SOURCE_ID 106** macro is a string which identifies a particular check-in of SQLite 107** within its configuration management system. The string contains the 108** date and time of the check-in (UTC) and an SHA1 hash of the entire 109** source tree. 110** 111** See also: [sqlite3_libversion()], 112** [sqlite3_libversion_number()], [sqlite3_sourceid()], 113** [sqlite_version()] and [sqlite_source_id()]. 114** 115** Requirements: [H10011] [H10014] 116*/ 117#define SQLITE_VERSION "--VERS--" 118#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 119#define SQLITE_SOURCE_ID "--SOURCE-ID--" 120 121/* 122** CAPI3REF: Run-Time Library Version Numbers {H10020} <S60100> 123** KEYWORDS: sqlite3_version 124** 125** These interfaces provide the same information as the [SQLITE_VERSION], 126** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] #defines in the header, 127** but are associated with the library instead of the header file. Cautious 128** programmers might include assert() statements in their application to 129** verify that values returned by these interfaces match the macros in 130** the header, and thus insure that the application is 131** compiled with matching library and header files. 132** 133** <blockquote><pre> 134** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 135** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 136** assert( strcmp(sqlite3_libversion,SQLITE_VERSION)==0 ); 137** </pre></blockquote> 138** 139** The sqlite3_libversion() function returns the same information as is 140** in the sqlite3_version[] string constant. The function is provided 141** for use in DLLs since DLL users usually do not have direct access to string 142** constants within the DLL. Similarly, the sqlite3_sourceid() function 143** returns the same information as is in the [SQLITE_SOURCE_ID] #define of 144** the header file. 145** 146** See also: [sqlite_version()] and [sqlite_source_id()]. 147** 148** Requirements: [H10021] [H10022] [H10023] 149*/ 150SQLITE_EXTERN const char sqlite3_version[]; 151const char *sqlite3_libversion(void); 152const char *sqlite3_sourceid(void); 153int sqlite3_libversion_number(void); 154 155/* 156** CAPI3REF: Test To See If The Library Is Threadsafe {H10100} <S60100> 157** 158** SQLite can be compiled with or without mutexes. When 159** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 160** are enabled and SQLite is threadsafe. When the 161** [SQLITE_THREADSAFE] macro is 0, 162** the mutexes are omitted. Without the mutexes, it is not safe 163** to use SQLite concurrently from more than one thread. 164** 165** Enabling mutexes incurs a measurable performance penalty. 166** So if speed is of utmost importance, it makes sense to disable 167** the mutexes. But for maximum safety, mutexes should be enabled. 168** The default behavior is for mutexes to be enabled. 169** 170** This interface can be used by an application to make sure that the 171** version of SQLite that it is linking against was compiled with 172** the desired setting of the [SQLITE_THREADSAFE] macro. 173** 174** This interface only reports on the compile-time mutex setting 175** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 176** SQLITE_THREADSAFE=1 then mutexes are enabled by default but 177** can be fully or partially disabled using a call to [sqlite3_config()] 178** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 179** or [SQLITE_CONFIG_MUTEX]. The return value of this function shows 180** only the default compile-time setting, not any run-time changes 181** to that setting. 182** 183** See the [threading mode] documentation for additional information. 184** 185** Requirements: [H10101] [H10102] 186*/ 187int sqlite3_threadsafe(void); 188 189/* 190** CAPI3REF: Database Connection Handle {H12000} <S40200> 191** KEYWORDS: {database connection} {database connections} 192** 193** Each open SQLite database is represented by a pointer to an instance of 194** the opaque structure named "sqlite3". It is useful to think of an sqlite3 195** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 196** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 197** is its destructor. There are many other interfaces (such as 198** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 199** [sqlite3_busy_timeout()] to name but three) that are methods on an 200** sqlite3 object. 201*/ 202typedef struct sqlite3 sqlite3; 203 204/* 205** CAPI3REF: 64-Bit Integer Types {H10200} <S10110> 206** KEYWORDS: sqlite_int64 sqlite_uint64 207** 208** Because there is no cross-platform way to specify 64-bit integer types 209** SQLite includes typedefs for 64-bit signed and unsigned integers. 210** 211** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 212** The sqlite_int64 and sqlite_uint64 types are supported for backwards 213** compatibility only. 214** 215** Requirements: [H10201] [H10202] 216*/ 217#ifdef SQLITE_INT64_TYPE 218 typedef SQLITE_INT64_TYPE sqlite_int64; 219 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 220#elif defined(_MSC_VER) || defined(__BORLANDC__) 221 typedef __int64 sqlite_int64; 222 typedef unsigned __int64 sqlite_uint64; 223#else 224 typedef long long int sqlite_int64; 225 typedef unsigned long long int sqlite_uint64; 226#endif 227typedef sqlite_int64 sqlite3_int64; 228typedef sqlite_uint64 sqlite3_uint64; 229 230/* 231** If compiling for a processor that lacks floating point support, 232** substitute integer for floating-point. 233*/ 234#ifdef SQLITE_OMIT_FLOATING_POINT 235# define double sqlite3_int64 236#endif 237 238/* 239** CAPI3REF: Closing A Database Connection {H12010} <S30100><S40200> 240** 241** This routine is the destructor for the [sqlite3] object. 242** 243** Applications must [sqlite3_finalize | finalize] all [prepared statements] 244** and [sqlite3_blob_close | close] all [BLOB handles] associated with 245** the [sqlite3] object prior to attempting to close the object. 246** 247** If [sqlite3_close()] is invoked while a transaction is open, 248** the transaction is automatically rolled back. 249** 250** The C parameter to [sqlite3_close(C)] must be either a NULL 251** pointer or an [sqlite3] object pointer obtained 252** from [sqlite3_open()], [sqlite3_open16()], or 253** [sqlite3_open_v2()], and not previously closed. 254** 255** Requirements: 256** [H12011] [H12012] [H12013] [H12014] [H12015] [H12019] 257*/ 258int sqlite3_close(sqlite3 *); 259 260/* 261** The type for a callback function. 262** This is legacy and deprecated. It is included for historical 263** compatibility and is not documented. 264*/ 265typedef int (*sqlite3_callback)(void*,int,char**, char**); 266 267/* 268** CAPI3REF: One-Step Query Execution Interface {H12100} <S10000> 269** 270** The sqlite3_exec() interface is a convenient way of running one or more 271** SQL statements without having to write a lot of C code. The UTF-8 encoded 272** SQL statements are passed in as the second parameter to sqlite3_exec(). 273** The statements are evaluated one by one until either an error or 274** an interrupt is encountered, or until they are all done. The 3rd parameter 275** is an optional callback that is invoked once for each row of any query 276** results produced by the SQL statements. The 5th parameter tells where 277** to write any error messages. 278** 279** The error message passed back through the 5th parameter is held 280** in memory obtained from [sqlite3_malloc()]. To avoid a memory leak, 281** the calling application should call [sqlite3_free()] on any error 282** message returned through the 5th parameter when it has finished using 283** the error message. 284** 285** If the SQL statement in the 2nd parameter is NULL or an empty string 286** or a string containing only whitespace and comments, then no SQL 287** statements are evaluated and the database is not changed. 288** 289** The sqlite3_exec() interface is implemented in terms of 290** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()]. 291** The sqlite3_exec() routine does nothing to the database that cannot be done 292** by [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()]. 293** 294** The first parameter to [sqlite3_exec()] must be an valid and open 295** [database connection]. 296** 297** The database connection must not be closed while 298** [sqlite3_exec()] is running. 299** 300** The calling function should use [sqlite3_free()] to free 301** the memory that *errmsg is left pointing at once the error 302** message is no longer needed. 303** 304** The SQL statement text in the 2nd parameter to [sqlite3_exec()] 305** must remain unchanged while [sqlite3_exec()] is running. 306** 307** Requirements: 308** [H12101] [H12102] [H12104] [H12105] [H12107] [H12110] [H12113] [H12116] 309** [H12119] [H12122] [H12125] [H12131] [H12134] [H12137] [H12138] 310*/ 311int sqlite3_exec( 312 sqlite3*, /* An open database */ 313 const char *sql, /* SQL to be evaluated */ 314 int (*callback)(void*,int,char**,char**), /* Callback function */ 315 void *, /* 1st argument to callback */ 316 char **errmsg /* Error msg written here */ 317); 318 319/* 320** CAPI3REF: Result Codes {H10210} <S10700> 321** KEYWORDS: SQLITE_OK {error code} {error codes} 322** KEYWORDS: {result code} {result codes} 323** 324** Many SQLite functions return an integer result code from the set shown 325** here in order to indicates success or failure. 326** 327** New error codes may be added in future versions of SQLite. 328** 329** See also: [SQLITE_IOERR_READ | extended result codes] 330*/ 331#define SQLITE_OK 0 /* Successful result */ 332/* beginning-of-error-codes */ 333#define SQLITE_ERROR 1 /* SQL error or missing database */ 334#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 335#define SQLITE_PERM 3 /* Access permission denied */ 336#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 337#define SQLITE_BUSY 5 /* The database file is locked */ 338#define SQLITE_LOCKED 6 /* A table in the database is locked */ 339#define SQLITE_NOMEM 7 /* A malloc() failed */ 340#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 341#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 342#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 343#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 344#define SQLITE_NOTFOUND 12 /* NOT USED. Table or record not found */ 345#define SQLITE_FULL 13 /* Insertion failed because database is full */ 346#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 347#define SQLITE_PROTOCOL 15 /* NOT USED. Database lock protocol error */ 348#define SQLITE_EMPTY 16 /* Database is empty */ 349#define SQLITE_SCHEMA 17 /* The database schema changed */ 350#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 351#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 352#define SQLITE_MISMATCH 20 /* Data type mismatch */ 353#define SQLITE_MISUSE 21 /* Library used incorrectly */ 354#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 355#define SQLITE_AUTH 23 /* Authorization denied */ 356#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 357#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 358#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 359#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 360#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 361/* end-of-error-codes */ 362 363/* 364** CAPI3REF: Extended Result Codes {H10220} <S10700> 365** KEYWORDS: {extended error code} {extended error codes} 366** KEYWORDS: {extended result code} {extended result codes} 367** 368** In its default configuration, SQLite API routines return one of 26 integer 369** [SQLITE_OK | result codes]. However, experience has shown that many of 370** these result codes are too coarse-grained. They do not provide as 371** much information about problems as programmers might like. In an effort to 372** address this, newer versions of SQLite (version 3.3.8 and later) include 373** support for additional result codes that provide more detailed information 374** about errors. The extended result codes are enabled or disabled 375** on a per database connection basis using the 376** [sqlite3_extended_result_codes()] API. 377** 378** Some of the available extended result codes are listed here. 379** One may expect the number of extended result codes will be expand 380** over time. Software that uses extended result codes should expect 381** to see new result codes in future releases of SQLite. 382** 383** The SQLITE_OK result code will never be extended. It will always 384** be exactly zero. 385*/ 386#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 387#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 388#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 389#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 390#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 391#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 392#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 393#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 394#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 395#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 396#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 397#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 398#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 399#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 400#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 401#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 402#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 403#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8) ) 404 405/* 406** CAPI3REF: Flags For File Open Operations {H10230} <H11120> <H12700> 407** 408** These bit values are intended for use in the 409** 3rd parameter to the [sqlite3_open_v2()] interface and 410** in the 4th parameter to the xOpen method of the 411** [sqlite3_vfs] object. 412*/ 413#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 414#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 415#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 416#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 417#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 418#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 419#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 420#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 421#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 422#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 423#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 424#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 425#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 426#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 427#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 428#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 429 430/* 431** CAPI3REF: Device Characteristics {H10240} <H11120> 432** 433** The xDeviceCapabilities method of the [sqlite3_io_methods] 434** object returns an integer which is a vector of the these 435** bit values expressing I/O characteristics of the mass storage 436** device that holds the file that the [sqlite3_io_methods] 437** refers to. 438** 439** The SQLITE_IOCAP_ATOMIC property means that all writes of 440** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 441** mean that writes of blocks that are nnn bytes in size and 442** are aligned to an address which is an integer multiple of 443** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 444** that when data is appended to a file, the data is appended 445** first then the size of the file is extended, never the other 446** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 447** information is written to disk in the same order as calls 448** to xWrite(). 449*/ 450#define SQLITE_IOCAP_ATOMIC 0x00000001 451#define SQLITE_IOCAP_ATOMIC512 0x00000002 452#define SQLITE_IOCAP_ATOMIC1K 0x00000004 453#define SQLITE_IOCAP_ATOMIC2K 0x00000008 454#define SQLITE_IOCAP_ATOMIC4K 0x00000010 455#define SQLITE_IOCAP_ATOMIC8K 0x00000020 456#define SQLITE_IOCAP_ATOMIC16K 0x00000040 457#define SQLITE_IOCAP_ATOMIC32K 0x00000080 458#define SQLITE_IOCAP_ATOMIC64K 0x00000100 459#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 460#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 461 462/* 463** CAPI3REF: File Locking Levels {H10250} <H11120> <H11310> 464** 465** SQLite uses one of these integer values as the second 466** argument to calls it makes to the xLock() and xUnlock() methods 467** of an [sqlite3_io_methods] object. 468*/ 469#define SQLITE_LOCK_NONE 0 470#define SQLITE_LOCK_SHARED 1 471#define SQLITE_LOCK_RESERVED 2 472#define SQLITE_LOCK_PENDING 3 473#define SQLITE_LOCK_EXCLUSIVE 4 474 475/* 476** CAPI3REF: Synchronization Type Flags {H10260} <H11120> 477** 478** When SQLite invokes the xSync() method of an 479** [sqlite3_io_methods] object it uses a combination of 480** these integer values as the second argument. 481** 482** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 483** sync operation only needs to flush data to mass storage. Inode 484** information need not be flushed. If the lower four bits of the flag 485** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 486** If the lower four bits equal SQLITE_SYNC_FULL, that means 487** to use Mac OS X style fullsync instead of fsync(). 488*/ 489#define SQLITE_SYNC_NORMAL 0x00002 490#define SQLITE_SYNC_FULL 0x00003 491#define SQLITE_SYNC_DATAONLY 0x00010 492 493/* 494** CAPI3REF: OS Interface Open File Handle {H11110} <S20110> 495** 496** An [sqlite3_file] object represents an open file in the 497** [sqlite3_vfs | OS interface layer]. Individual OS interface 498** implementations will 499** want to subclass this object by appending additional fields 500** for their own use. The pMethods entry is a pointer to an 501** [sqlite3_io_methods] object that defines methods for performing 502** I/O operations on the open file. 503*/ 504typedef struct sqlite3_file sqlite3_file; 505struct sqlite3_file { 506 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 507}; 508 509/* 510** CAPI3REF: OS Interface File Virtual Methods Object {H11120} <S20110> 511** 512** Every file opened by the [sqlite3_vfs] xOpen method populates an 513** [sqlite3_file] object (or, more commonly, a subclass of the 514** [sqlite3_file] object) with a pointer to an instance of this object. 515** This object defines the methods used to perform various operations 516** against the open file represented by the [sqlite3_file] object. 517** 518** If the xOpen method sets the sqlite3_file.pMethods element 519** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 520** may be invoked even if the xOpen reported that it failed. The 521** only way to prevent a call to xClose following a failed xOpen 522** is for the xOpen to set the sqlite3_file.pMethods element to NULL. 523** 524** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 525** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 526** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 527** flag may be ORed in to indicate that only the data of the file 528** and not its inode needs to be synced. 529** 530** The integer values to xLock() and xUnlock() are one of 531** <ul> 532** <li> [SQLITE_LOCK_NONE], 533** <li> [SQLITE_LOCK_SHARED], 534** <li> [SQLITE_LOCK_RESERVED], 535** <li> [SQLITE_LOCK_PENDING], or 536** <li> [SQLITE_LOCK_EXCLUSIVE]. 537** </ul> 538** xLock() increases the lock. xUnlock() decreases the lock. 539** The xCheckReservedLock() method checks whether any database connection, 540** either in this process or in some other process, is holding a RESERVED, 541** PENDING, or EXCLUSIVE lock on the file. It returns true 542** if such a lock exists and false otherwise. 543** 544** The xFileControl() method is a generic interface that allows custom 545** VFS implementations to directly control an open file using the 546** [sqlite3_file_control()] interface. The second "op" argument is an 547** integer opcode. The third argument is a generic pointer intended to 548** point to a structure that may contain arguments or space in which to 549** write return values. Potential uses for xFileControl() might be 550** functions to enable blocking locks with timeouts, to change the 551** locking strategy (for example to use dot-file locks), to inquire 552** about the status of a lock, or to break stale locks. The SQLite 553** core reserves all opcodes less than 100 for its own use. 554** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 555** Applications that define a custom xFileControl method should use opcodes 556** greater than 100 to avoid conflicts. 557** 558** The xSectorSize() method returns the sector size of the 559** device that underlies the file. The sector size is the 560** minimum write that can be performed without disturbing 561** other bytes in the file. The xDeviceCharacteristics() 562** method returns a bit vector describing behaviors of the 563** underlying device: 564** 565** <ul> 566** <li> [SQLITE_IOCAP_ATOMIC] 567** <li> [SQLITE_IOCAP_ATOMIC512] 568** <li> [SQLITE_IOCAP_ATOMIC1K] 569** <li> [SQLITE_IOCAP_ATOMIC2K] 570** <li> [SQLITE_IOCAP_ATOMIC4K] 571** <li> [SQLITE_IOCAP_ATOMIC8K] 572** <li> [SQLITE_IOCAP_ATOMIC16K] 573** <li> [SQLITE_IOCAP_ATOMIC32K] 574** <li> [SQLITE_IOCAP_ATOMIC64K] 575** <li> [SQLITE_IOCAP_SAFE_APPEND] 576** <li> [SQLITE_IOCAP_SEQUENTIAL] 577** </ul> 578** 579** The SQLITE_IOCAP_ATOMIC property means that all writes of 580** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 581** mean that writes of blocks that are nnn bytes in size and 582** are aligned to an address which is an integer multiple of 583** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 584** that when data is appended to a file, the data is appended 585** first then the size of the file is extended, never the other 586** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 587** information is written to disk in the same order as calls 588** to xWrite(). 589** 590** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 591** in the unread portions of the buffer with zeros. A VFS that 592** fails to zero-fill short reads might seem to work. However, 593** failure to zero-fill short reads will eventually lead to 594** database corruption. 595*/ 596typedef struct sqlite3_io_methods sqlite3_io_methods; 597struct sqlite3_io_methods { 598 int iVersion; 599 int (*xClose)(sqlite3_file*); 600 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 601 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 602 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 603 int (*xSync)(sqlite3_file*, int flags); 604 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 605 int (*xLock)(sqlite3_file*, int); 606 int (*xUnlock)(sqlite3_file*, int); 607 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 608 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 609 int (*xSectorSize)(sqlite3_file*); 610 int (*xDeviceCharacteristics)(sqlite3_file*); 611 /* Additional methods may be added in future releases */ 612}; 613 614/* 615** CAPI3REF: Standard File Control Opcodes {H11310} <S30800> 616** 617** These integer constants are opcodes for the xFileControl method 618** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 619** interface. 620** 621** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 622** opcode causes the xFileControl method to write the current state of 623** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 624** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 625** into an integer that the pArg argument points to. This capability 626** is used during testing and only needs to be supported when SQLITE_TEST 627** is defined. 628*/ 629#define SQLITE_FCNTL_LOCKSTATE 1 630#define SQLITE_GET_LOCKPROXYFILE 2 631#define SQLITE_SET_LOCKPROXYFILE 3 632#define SQLITE_LAST_ERRNO 4 633 634/* 635** CAPI3REF: Mutex Handle {H17110} <S20130> 636** 637** The mutex module within SQLite defines [sqlite3_mutex] to be an 638** abstract type for a mutex object. The SQLite core never looks 639** at the internal representation of an [sqlite3_mutex]. It only 640** deals with pointers to the [sqlite3_mutex] object. 641** 642** Mutexes are created using [sqlite3_mutex_alloc()]. 643*/ 644typedef struct sqlite3_mutex sqlite3_mutex; 645 646/* 647** CAPI3REF: OS Interface Object {H11140} <S20100> 648** 649** An instance of the sqlite3_vfs object defines the interface between 650** the SQLite core and the underlying operating system. The "vfs" 651** in the name of the object stands for "virtual file system". 652** 653** The value of the iVersion field is initially 1 but may be larger in 654** future versions of SQLite. Additional fields may be appended to this 655** object when the iVersion value is increased. Note that the structure 656** of the sqlite3_vfs object changes in the transaction between 657** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 658** modified. 659** 660** The szOsFile field is the size of the subclassed [sqlite3_file] 661** structure used by this VFS. mxPathname is the maximum length of 662** a pathname in this VFS. 663** 664** Registered sqlite3_vfs objects are kept on a linked list formed by 665** the pNext pointer. The [sqlite3_vfs_register()] 666** and [sqlite3_vfs_unregister()] interfaces manage this list 667** in a thread-safe way. The [sqlite3_vfs_find()] interface 668** searches the list. Neither the application code nor the VFS 669** implementation should use the pNext pointer. 670** 671** The pNext field is the only field in the sqlite3_vfs 672** structure that SQLite will ever modify. SQLite will only access 673** or modify this field while holding a particular static mutex. 674** The application should never modify anything within the sqlite3_vfs 675** object once the object has been registered. 676** 677** The zName field holds the name of the VFS module. The name must 678** be unique across all VFS modules. 679** 680** SQLite will guarantee that the zFilename parameter to xOpen 681** is either a NULL pointer or string obtained 682** from xFullPathname(). SQLite further guarantees that 683** the string will be valid and unchanged until xClose() is 684** called. Because of the previous sentence, 685** the [sqlite3_file] can safely store a pointer to the 686** filename if it needs to remember the filename for some reason. 687** If the zFilename parameter is xOpen is a NULL pointer then xOpen 688** must invent its own temporary name for the file. Whenever the 689** xFilename parameter is NULL it will also be the case that the 690** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 691** 692** The flags argument to xOpen() includes all bits set in 693** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 694** or [sqlite3_open16()] is used, then flags includes at least 695** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 696** If xOpen() opens a file read-only then it sets *pOutFlags to 697** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 698** 699** SQLite will also add one of the following flags to the xOpen() 700** call, depending on the object being opened: 701** 702** <ul> 703** <li> [SQLITE_OPEN_MAIN_DB] 704** <li> [SQLITE_OPEN_MAIN_JOURNAL] 705** <li> [SQLITE_OPEN_TEMP_DB] 706** <li> [SQLITE_OPEN_TEMP_JOURNAL] 707** <li> [SQLITE_OPEN_TRANSIENT_DB] 708** <li> [SQLITE_OPEN_SUBJOURNAL] 709** <li> [SQLITE_OPEN_MASTER_JOURNAL] 710** </ul> 711** 712** The file I/O implementation can use the object type flags to 713** change the way it deals with files. For example, an application 714** that does not care about crash recovery or rollback might make 715** the open of a journal file a no-op. Writes to this journal would 716** also be no-ops, and any attempt to read the journal would return 717** SQLITE_IOERR. Or the implementation might recognize that a database 718** file will be doing page-aligned sector reads and writes in a random 719** order and set up its I/O subsystem accordingly. 720** 721** SQLite might also add one of the following flags to the xOpen method: 722** 723** <ul> 724** <li> [SQLITE_OPEN_DELETEONCLOSE] 725** <li> [SQLITE_OPEN_EXCLUSIVE] 726** </ul> 727** 728** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 729** deleted when it is closed. The [SQLITE_OPEN_DELETEONCLOSE] 730** will be set for TEMP databases, journals and for subjournals. 731** 732** The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 733** with the [SQLITE_OPEN_CREATE] flag, which are both directly 734** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 735** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 736** SQLITE_OPEN_CREATE, is used to indicate that file should always 737** be created, and that it is an error if it already exists. 738** It is <i>not</i> used to indicate the file should be opened 739** for exclusive access. 740** 741** At least szOsFile bytes of memory are allocated by SQLite 742** to hold the [sqlite3_file] structure passed as the third 743** argument to xOpen. The xOpen method does not have to 744** allocate the structure; it should just fill it in. Note that 745** the xOpen method must set the sqlite3_file.pMethods to either 746** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 747** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 748** element will be valid after xOpen returns regardless of the success 749** or failure of the xOpen call. 750** 751** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 752** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 753** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 754** to test whether a file is at least readable. The file can be a 755** directory. 756** 757** SQLite will always allocate at least mxPathname+1 bytes for the 758** output buffer xFullPathname. The exact size of the output buffer 759** is also passed as a parameter to both methods. If the output buffer 760** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 761** handled as a fatal error by SQLite, vfs implementations should endeavor 762** to prevent this by setting mxPathname to a sufficiently large value. 763** 764** The xRandomness(), xSleep(), and xCurrentTime() interfaces 765** are not strictly a part of the filesystem, but they are 766** included in the VFS structure for completeness. 767** The xRandomness() function attempts to return nBytes bytes 768** of good-quality randomness into zOut. The return value is 769** the actual number of bytes of randomness obtained. 770** The xSleep() method causes the calling thread to sleep for at 771** least the number of microseconds given. The xCurrentTime() 772** method returns a Julian Day Number for the current date and time. 773** 774*/ 775typedef struct sqlite3_vfs sqlite3_vfs; 776struct sqlite3_vfs { 777 int iVersion; /* Structure version number */ 778 int szOsFile; /* Size of subclassed sqlite3_file */ 779 int mxPathname; /* Maximum file pathname length */ 780 sqlite3_vfs *pNext; /* Next registered VFS */ 781 const char *zName; /* Name of this virtual file system */ 782 void *pAppData; /* Pointer to application-specific data */ 783 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 784 int flags, int *pOutFlags); 785 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 786 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 787 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 788 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 789 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 790 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 791 void (*xDlClose)(sqlite3_vfs*, void*); 792 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 793 int (*xSleep)(sqlite3_vfs*, int microseconds); 794 int (*xCurrentTime)(sqlite3_vfs*, double*); 795 int (*xGetLastError)(sqlite3_vfs*, int, char *); 796 /* New fields may be appended in figure versions. The iVersion 797 ** value will increment whenever this happens. */ 798}; 799 800/* 801** CAPI3REF: Flags for the xAccess VFS method {H11190} <H11140> 802** 803** These integer constants can be used as the third parameter to 804** the xAccess method of an [sqlite3_vfs] object. {END} They determine 805** what kind of permissions the xAccess method is looking for. 806** With SQLITE_ACCESS_EXISTS, the xAccess method 807** simply checks whether the file exists. 808** With SQLITE_ACCESS_READWRITE, the xAccess method 809** checks whether the file is both readable and writable. 810** With SQLITE_ACCESS_READ, the xAccess method 811** checks whether the file is readable. 812*/ 813#define SQLITE_ACCESS_EXISTS 0 814#define SQLITE_ACCESS_READWRITE 1 815#define SQLITE_ACCESS_READ 2 816 817/* 818** CAPI3REF: Initialize The SQLite Library {H10130} <S20000><S30100> 819** 820** The sqlite3_initialize() routine initializes the 821** SQLite library. The sqlite3_shutdown() routine 822** deallocates any resources that were allocated by sqlite3_initialize(). 823** These routines are designed to aid in process initialization and 824** shutdown on embedded systems. Workstation applications using 825** SQLite normally do not need to invoke either of these routines. 826** 827** A call to sqlite3_initialize() is an "effective" call if it is 828** the first time sqlite3_initialize() is invoked during the lifetime of 829** the process, or if it is the first time sqlite3_initialize() is invoked 830** following a call to sqlite3_shutdown(). Only an effective call 831** of sqlite3_initialize() does any initialization. All other calls 832** are harmless no-ops. 833** 834** A call to sqlite3_shutdown() is an "effective" call if it is the first 835** call to sqlite3_shutdown() since the last sqlite3_initialize(). Only 836** an effective call to sqlite3_shutdown() does any deinitialization. 837** All other valid calls to sqlite3_shutdown() are harmless no-ops. 838** 839** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 840** is not. The sqlite3_shutdown() interface must only be called from a 841** single thread. All open [database connections] must be closed and all 842** other SQLite resources must be deallocated prior to invoking 843** sqlite3_shutdown(). 844** 845** Among other things, sqlite3_initialize() will invoke 846** sqlite3_os_init(). Similarly, sqlite3_shutdown() 847** will invoke sqlite3_os_end(). 848** 849** The sqlite3_initialize() routine returns [SQLITE_OK] on success. 850** If for some reason, sqlite3_initialize() is unable to initialize 851** the library (perhaps it is unable to allocate a needed resource such 852** as a mutex) it returns an [error code] other than [SQLITE_OK]. 853** 854** The sqlite3_initialize() routine is called internally by many other 855** SQLite interfaces so that an application usually does not need to 856** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 857** calls sqlite3_initialize() so the SQLite library will be automatically 858** initialized when [sqlite3_open()] is called if it has not be initialized 859** already. However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 860** compile-time option, then the automatic calls to sqlite3_initialize() 861** are omitted and the application must call sqlite3_initialize() directly 862** prior to using any other SQLite interface. For maximum portability, 863** it is recommended that applications always invoke sqlite3_initialize() 864** directly prior to using any other SQLite interface. Future releases 865** of SQLite may require this. In other words, the behavior exhibited 866** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 867** default behavior in some future release of SQLite. 868** 869** The sqlite3_os_init() routine does operating-system specific 870** initialization of the SQLite library. The sqlite3_os_end() 871** routine undoes the effect of sqlite3_os_init(). Typical tasks 872** performed by these routines include allocation or deallocation 873** of static resources, initialization of global variables, 874** setting up a default [sqlite3_vfs] module, or setting up 875** a default configuration using [sqlite3_config()]. 876** 877** The application should never invoke either sqlite3_os_init() 878** or sqlite3_os_end() directly. The application should only invoke 879** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 880** interface is called automatically by sqlite3_initialize() and 881** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 882** implementations for sqlite3_os_init() and sqlite3_os_end() 883** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 884** When [custom builds | built for other platforms] 885** (using the [SQLITE_OS_OTHER=1] compile-time 886** option) the application must supply a suitable implementation for 887** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 888** implementation of sqlite3_os_init() or sqlite3_os_end() 889** must return [SQLITE_OK] on success and some other [error code] upon 890** failure. 891*/ 892int sqlite3_initialize(void); 893int sqlite3_shutdown(void); 894int sqlite3_os_init(void); 895int sqlite3_os_end(void); 896 897/* 898** CAPI3REF: Configuring The SQLite Library {H14100} <S20000><S30200> 899** EXPERIMENTAL 900** 901** The sqlite3_config() interface is used to make global configuration 902** changes to SQLite in order to tune SQLite to the specific needs of 903** the application. The default configuration is recommended for most 904** applications and so this routine is usually not necessary. It is 905** provided to support rare applications with unusual needs. 906** 907** The sqlite3_config() interface is not threadsafe. The application 908** must insure that no other SQLite interfaces are invoked by other 909** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 910** may only be invoked prior to library initialization using 911** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 912** Note, however, that sqlite3_config() can be called as part of the 913** implementation of an application-defined [sqlite3_os_init()]. 914** 915** The first argument to sqlite3_config() is an integer 916** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines 917** what property of SQLite is to be configured. Subsequent arguments 918** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option] 919** in the first argument. 920** 921** When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 922** If the option is unknown or SQLite is unable to set the option 923** then this routine returns a non-zero [error code]. 924** 925** Requirements: 926** [H14103] [H14106] [H14120] [H14123] [H14126] [H14129] [H14132] [H14135] 927** [H14138] [H14141] [H14144] [H14147] [H14150] [H14153] [H14156] [H14159] 928** [H14162] [H14165] [H14168] 929*/ 930SQLITE_EXPERIMENTAL int sqlite3_config(int, ...); 931 932/* 933** CAPI3REF: Configure database connections {H14200} <S20000> 934** EXPERIMENTAL 935** 936** The sqlite3_db_config() interface is used to make configuration 937** changes to a [database connection]. The interface is similar to 938** [sqlite3_config()] except that the changes apply to a single 939** [database connection] (specified in the first argument). The 940** sqlite3_db_config() interface can only be used immediately after 941** the database connection is created using [sqlite3_open()], 942** [sqlite3_open16()], or [sqlite3_open_v2()]. 943** 944** The second argument to sqlite3_db_config(D,V,...) is the 945** configuration verb - an integer code that indicates what 946** aspect of the [database connection] is being configured. 947** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE]. 948** New verbs are likely to be added in future releases of SQLite. 949** Additional arguments depend on the verb. 950** 951** Requirements: 952** [H14203] [H14206] [H14209] [H14212] [H14215] 953*/ 954SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...); 955 956/* 957** CAPI3REF: Memory Allocation Routines {H10155} <S20120> 958** EXPERIMENTAL 959** 960** An instance of this object defines the interface between SQLite 961** and low-level memory allocation routines. 962** 963** This object is used in only one place in the SQLite interface. 964** A pointer to an instance of this object is the argument to 965** [sqlite3_config()] when the configuration option is 966** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 967** By creating an instance of this object 968** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 969** during configuration, an application can specify an alternative 970** memory allocation subsystem for SQLite to use for all of its 971** dynamic memory needs. 972** 973** Note that SQLite comes with several [built-in memory allocators] 974** that are perfectly adequate for the overwhelming majority of applications 975** and that this object is only useful to a tiny minority of applications 976** with specialized memory allocation requirements. This object is 977** also used during testing of SQLite in order to specify an alternative 978** memory allocator that simulates memory out-of-memory conditions in 979** order to verify that SQLite recovers gracefully from such 980** conditions. 981** 982** The xMalloc and xFree methods must work like the 983** malloc() and free() functions from the standard C library. 984** The xRealloc method must work like realloc() from the standard C library 985** with the exception that if the second argument to xRealloc is zero, 986** xRealloc must be a no-op - it must not perform any allocation or 987** deallocation. SQLite guaranteeds that the second argument to 988** xRealloc is always a value returned by a prior call to xRoundup. 989** And so in cases where xRoundup always returns a positive number, 990** xRealloc can perform exactly as the standard library realloc() and 991** still be in compliance with this specification. 992** 993** xSize should return the allocated size of a memory allocation 994** previously obtained from xMalloc or xRealloc. The allocated size 995** is always at least as big as the requested size but may be larger. 996** 997** The xRoundup method returns what would be the allocated size of 998** a memory allocation given a particular requested size. Most memory 999** allocators round up memory allocations at least to the next multiple 1000** of 8. Some allocators round up to a larger multiple or to a power of 2. 1001** Every memory allocation request coming in through [sqlite3_malloc()] 1002** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1003** that causes the corresponding memory allocation to fail. 1004** 1005** The xInit method initializes the memory allocator. (For example, 1006** it might allocate any require mutexes or initialize internal data 1007** structures. The xShutdown method is invoked (indirectly) by 1008** [sqlite3_shutdown()] and should deallocate any resources acquired 1009** by xInit. The pAppData pointer is used as the only parameter to 1010** xInit and xShutdown. 1011** 1012** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1013** the xInit method, so the xInit method need not be threadsafe. The 1014** xShutdown method is only called from [sqlite3_shutdown()] so it does 1015** not need to be threadsafe either. For all other methods, SQLite 1016** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1017** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1018** it is by default) and so the methods are automatically serialized. 1019** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1020** methods must be threadsafe or else make their own arrangements for 1021** serialization. 1022** 1023** SQLite will never invoke xInit() more than once without an intervening 1024** call to xShutdown(). 1025*/ 1026typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1027struct sqlite3_mem_methods { 1028 void *(*xMalloc)(int); /* Memory allocation function */ 1029 void (*xFree)(void*); /* Free a prior allocation */ 1030 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1031 int (*xSize)(void*); /* Return the size of an allocation */ 1032 int (*xRoundup)(int); /* Round up request size to allocation size */ 1033 int (*xInit)(void*); /* Initialize the memory allocator */ 1034 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1035 void *pAppData; /* Argument to xInit() and xShutdown() */ 1036}; 1037 1038/* 1039** CAPI3REF: Configuration Options {H10160} <S20000> 1040** EXPERIMENTAL 1041** 1042** These constants are the available integer configuration options that 1043** can be passed as the first argument to the [sqlite3_config()] interface. 1044** 1045** New configuration options may be added in future releases of SQLite. 1046** Existing configuration options might be discontinued. Applications 1047** should check the return code from [sqlite3_config()] to make sure that 1048** the call worked. The [sqlite3_config()] interface will return a 1049** non-zero [error code] if a discontinued or unsupported configuration option 1050** is invoked. 1051** 1052** <dl> 1053** <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1054** <dd>There are no arguments to this option. This option disables 1055** all mutexing and puts SQLite into a mode where it can only be used 1056** by a single thread.</dd> 1057** 1058** <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1059** <dd>There are no arguments to this option. This option disables 1060** mutexing on [database connection] and [prepared statement] objects. 1061** The application is responsible for serializing access to 1062** [database connections] and [prepared statements]. But other mutexes 1063** are enabled so that SQLite will be safe to use in a multi-threaded 1064** environment as long as no two threads attempt to use the same 1065** [database connection] at the same time. See the [threading mode] 1066** documentation for additional information.</dd> 1067** 1068** <dt>SQLITE_CONFIG_SERIALIZED</dt> 1069** <dd>There are no arguments to this option. This option enables 1070** all mutexes including the recursive 1071** mutexes on [database connection] and [prepared statement] objects. 1072** In this mode (which is the default when SQLite is compiled with 1073** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1074** to [database connections] and [prepared statements] so that the 1075** application is free to use the same [database connection] or the 1076** same [prepared statement] in different threads at the same time. 1077** See the [threading mode] documentation for additional information.</dd> 1078** 1079** <dt>SQLITE_CONFIG_MALLOC</dt> 1080** <dd>This option takes a single argument which is a pointer to an 1081** instance of the [sqlite3_mem_methods] structure. The argument specifies 1082** alternative low-level memory allocation routines to be used in place of 1083** the memory allocation routines built into SQLite.</dd> 1084** 1085** <dt>SQLITE_CONFIG_GETMALLOC</dt> 1086** <dd>This option takes a single argument which is a pointer to an 1087** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1088** structure is filled with the currently defined memory allocation routines. 1089** This option can be used to overload the default memory allocation 1090** routines with a wrapper that simulations memory allocation failure or 1091** tracks memory usage, for example.</dd> 1092** 1093** <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1094** <dd>This option takes single argument of type int, interpreted as a 1095** boolean, which enables or disables the collection of memory allocation 1096** statistics. When disabled, the following SQLite interfaces become 1097** non-operational: 1098** <ul> 1099** <li> [sqlite3_memory_used()] 1100** <li> [sqlite3_memory_highwater()] 1101** <li> [sqlite3_soft_heap_limit()] 1102** <li> [sqlite3_status()] 1103** </ul> 1104** </dd> 1105** 1106** <dt>SQLITE_CONFIG_SCRATCH</dt> 1107** <dd>This option specifies a static memory buffer that SQLite can use for 1108** scratch memory. There are three arguments: A pointer an 8-byte 1109** aligned memory buffer from which the scrach allocations will be 1110** drawn, the size of each scratch allocation (sz), 1111** and the maximum number of scratch allocations (N). The sz 1112** argument must be a multiple of 16. The sz parameter should be a few bytes 1113** larger than the actual scratch space required due to internal overhead. 1114** The first argument should pointer to an 8-byte aligned buffer 1115** of at least sz*N bytes of memory. 1116** SQLite will use no more than one scratch buffer at once per thread, so 1117** N should be set to the expected maximum number of threads. The sz 1118** parameter should be 6 times the size of the largest database page size. 1119** Scratch buffers are used as part of the btree balance operation. If 1120** The btree balancer needs additional memory beyond what is provided by 1121** scratch buffers or if no scratch buffer space is specified, then SQLite 1122** goes to [sqlite3_malloc()] to obtain the memory it needs.</dd> 1123** 1124** <dt>SQLITE_CONFIG_PAGECACHE</dt> 1125** <dd>This option specifies a static memory buffer that SQLite can use for 1126** the database page cache with the default page cache implemenation. 1127** This configuration should not be used if an application-define page 1128** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option. 1129** There are three arguments to this option: A pointer to 8-byte aligned 1130** memory, the size of each page buffer (sz), and the number of pages (N). 1131** The sz argument should be the size of the largest database page 1132** (a power of two between 512 and 32768) plus a little extra for each 1133** page header. The page header size is 20 to 40 bytes depending on 1134** the host architecture. It is harmless, apart from the wasted memory, 1135** to make sz a little too large. The first 1136** argument should point to an allocation of at least sz*N bytes of memory. 1137** SQLite will use the memory provided by the first argument to satisfy its 1138** memory needs for the first N pages that it adds to cache. If additional 1139** page cache memory is needed beyond what is provided by this option, then 1140** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1141** The implementation might use one or more of the N buffers to hold 1142** memory accounting information. The pointer in the first argument must 1143** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1144** will be undefined.</dd> 1145** 1146** <dt>SQLITE_CONFIG_HEAP</dt> 1147** <dd>This option specifies a static memory buffer that SQLite will use 1148** for all of its dynamic memory allocation needs beyond those provided 1149** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1150** There are three arguments: An 8-byte aligned pointer to the memory, 1151** the number of bytes in the memory buffer, and the minimum allocation size. 1152** If the first pointer (the memory pointer) is NULL, then SQLite reverts 1153** to using its default memory allocator (the system malloc() implementation), 1154** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. If the 1155** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1156** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1157** allocator is engaged to handle all of SQLites memory allocation needs. 1158** The first pointer (the memory pointer) must be aligned to an 8-byte 1159** boundary or subsequent behavior of SQLite will be undefined.</dd> 1160** 1161** <dt>SQLITE_CONFIG_MUTEX</dt> 1162** <dd>This option takes a single argument which is a pointer to an 1163** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1164** alternative low-level mutex routines to be used in place 1165** the mutex routines built into SQLite.</dd> 1166** 1167** <dt>SQLITE_CONFIG_GETMUTEX</dt> 1168** <dd>This option takes a single argument which is a pointer to an 1169** instance of the [sqlite3_mutex_methods] structure. The 1170** [sqlite3_mutex_methods] 1171** structure is filled with the currently defined mutex routines. 1172** This option can be used to overload the default mutex allocation 1173** routines with a wrapper used to track mutex usage for performance 1174** profiling or testing, for example.</dd> 1175** 1176** <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1177** <dd>This option takes two arguments that determine the default 1178** memory allocation lookaside optimization. The first argument is the 1179** size of each lookaside buffer slot and the second is the number of 1180** slots allocated to each database connection. This option sets the 1181** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1182** verb to [sqlite3_db_config()] can be used to change the lookaside 1183** configuration on individual connections.</dd> 1184** 1185** <dt>SQLITE_CONFIG_PCACHE</dt> 1186** <dd>This option takes a single argument which is a pointer to 1187** an [sqlite3_pcache_methods] object. This object specifies the interface 1188** to a custom page cache implementation. SQLite makes a copy of the 1189** object and uses it for page cache memory allocations.</dd> 1190** 1191** <dt>SQLITE_CONFIG_GETPCACHE</dt> 1192** <dd>This option takes a single argument which is a pointer to an 1193** [sqlite3_pcache_methods] object. SQLite copies of the current 1194** page cache implementation into that object.</dd> 1195** 1196** </dl> 1197*/ 1198#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1199#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1200#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1201#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1202#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1203#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1204#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1205#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1206#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1207#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1208#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1209/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1210#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1211#define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */ 1212#define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */ 1213 1214/* 1215** CAPI3REF: Configuration Options {H10170} <S20000> 1216** EXPERIMENTAL 1217** 1218** These constants are the available integer configuration options that 1219** can be passed as the second argument to the [sqlite3_db_config()] interface. 1220** 1221** New configuration options may be added in future releases of SQLite. 1222** Existing configuration options might be discontinued. Applications 1223** should check the return code from [sqlite3_db_config()] to make sure that 1224** the call worked. The [sqlite3_db_config()] interface will return a 1225** non-zero [error code] if a discontinued or unsupported configuration option 1226** is invoked. 1227** 1228** <dl> 1229** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1230** <dd>This option takes three additional arguments that determine the 1231** [lookaside memory allocator] configuration for the [database connection]. 1232** The first argument (the third parameter to [sqlite3_db_config()] is a 1233** pointer to an memory buffer to use for lookaside memory. 1234** The first argument may be NULL in which case SQLite will allocate the 1235** lookaside buffer itself using [sqlite3_malloc()]. The second argument is the 1236** size of each lookaside buffer slot and the third argument is the number of 1237** slots. The size of the buffer in the first argument must be greater than 1238** or equal to the product of the second and third arguments. The buffer 1239** must be aligned to an 8-byte boundary. If the second argument is not 1240** a multiple of 8, it is internally rounded down to the next smaller 1241** multiple of 8. See also: [SQLITE_CONFIG_LOOKASIDE]</dd> 1242** 1243** </dl> 1244*/ 1245#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1246 1247 1248/* 1249** CAPI3REF: Enable Or Disable Extended Result Codes {H12200} <S10700> 1250** 1251** The sqlite3_extended_result_codes() routine enables or disables the 1252** [extended result codes] feature of SQLite. The extended result 1253** codes are disabled by default for historical compatibility considerations. 1254** 1255** Requirements: 1256** [H12201] [H12202] 1257*/ 1258int sqlite3_extended_result_codes(sqlite3*, int onoff); 1259 1260/* 1261** CAPI3REF: Last Insert Rowid {H12220} <S10700> 1262** 1263** Each entry in an SQLite table has a unique 64-bit signed 1264** integer key called the [ROWID | "rowid"]. The rowid is always available 1265** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1266** names are not also used by explicitly declared columns. If 1267** the table has a column of type [INTEGER PRIMARY KEY] then that column 1268** is another alias for the rowid. 1269** 1270** This routine returns the [rowid] of the most recent 1271** successful [INSERT] into the database from the [database connection] 1272** in the first argument. If no successful [INSERT]s 1273** have ever occurred on that database connection, zero is returned. 1274** 1275** If an [INSERT] occurs within a trigger, then the [rowid] of the inserted 1276** row is returned by this routine as long as the trigger is running. 1277** But once the trigger terminates, the value returned by this routine 1278** reverts to the last value inserted before the trigger fired. 1279** 1280** An [INSERT] that fails due to a constraint violation is not a 1281** successful [INSERT] and does not change the value returned by this 1282** routine. Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1283** and INSERT OR ABORT make no changes to the return value of this 1284** routine when their insertion fails. When INSERT OR REPLACE 1285** encounters a constraint violation, it does not fail. The 1286** INSERT continues to completion after deleting rows that caused 1287** the constraint problem so INSERT OR REPLACE will always change 1288** the return value of this interface. 1289** 1290** For the purposes of this routine, an [INSERT] is considered to 1291** be successful even if it is subsequently rolled back. 1292** 1293** Requirements: 1294** [H12221] [H12223] 1295** 1296** If a separate thread performs a new [INSERT] on the same 1297** database connection while the [sqlite3_last_insert_rowid()] 1298** function is running and thus changes the last insert [rowid], 1299** then the value returned by [sqlite3_last_insert_rowid()] is 1300** unpredictable and might not equal either the old or the new 1301** last insert [rowid]. 1302*/ 1303sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1304 1305/* 1306** CAPI3REF: Count The Number Of Rows Modified {H12240} <S10600> 1307** 1308** This function returns the number of database rows that were changed 1309** or inserted or deleted by the most recently completed SQL statement 1310** on the [database connection] specified by the first parameter. 1311** Only changes that are directly specified by the [INSERT], [UPDATE], 1312** or [DELETE] statement are counted. Auxiliary changes caused by 1313** triggers or [foreign key actions] are not counted. Use the 1314** [sqlite3_total_changes()] function to find the total number of changes 1315** including changes caused by triggers and foreign key actions. 1316** 1317** Changes to a view that are simulated by an [INSTEAD OF trigger] 1318** are not counted. Only real table changes are counted. 1319** 1320** A "row change" is a change to a single row of a single table 1321** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1322** are changed as side effects of [REPLACE] constraint resolution, 1323** rollback, ABORT processing, [DROP TABLE], or by any other 1324** mechanisms do not count as direct row changes. 1325** 1326** A "trigger context" is a scope of execution that begins and 1327** ends with the script of a [CREATE TRIGGER | trigger]. 1328** Most SQL statements are 1329** evaluated outside of any trigger. This is the "top level" 1330** trigger context. If a trigger fires from the top level, a 1331** new trigger context is entered for the duration of that one 1332** trigger. Subtriggers create subcontexts for their duration. 1333** 1334** Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1335** not create a new trigger context. 1336** 1337** This function returns the number of direct row changes in the 1338** most recent INSERT, UPDATE, or DELETE statement within the same 1339** trigger context. 1340** 1341** Thus, when called from the top level, this function returns the 1342** number of changes in the most recent INSERT, UPDATE, or DELETE 1343** that also occurred at the top level. Within the body of a trigger, 1344** the sqlite3_changes() interface can be called to find the number of 1345** changes in the most recently completed INSERT, UPDATE, or DELETE 1346** statement within the body of the same trigger. 1347** However, the number returned does not include changes 1348** caused by subtriggers since those have their own context. 1349** 1350** See also the [sqlite3_total_changes()] interface and the 1351** [count_changes pragma]. 1352** 1353** Requirements: 1354** [H12241] [H12243] 1355** 1356** If a separate thread makes changes on the same database connection 1357** while [sqlite3_changes()] is running then the value returned 1358** is unpredictable and not meaningful. 1359*/ 1360int sqlite3_changes(sqlite3*); 1361 1362/* 1363** CAPI3REF: Total Number Of Rows Modified {H12260} <S10600> 1364** 1365** This function returns the number of row changes caused by [INSERT], 1366** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1367** The count includes all changes from all [CREATE TRIGGER | trigger] 1368** contexts and changes made by [foreign key actions]. However, 1369** the count does not include changes used to implement [REPLACE] constraints, 1370** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1371** count does not include rows of views that fire an [INSTEAD OF trigger], 1372** though if the INSTEAD OF trigger makes changes of its own, those changes 1373** are counted. 1374** The changes are counted as soon as the statement that makes them is 1375** completed (when the statement handle is passed to [sqlite3_reset()] or 1376** [sqlite3_finalize()]). 1377** 1378** See also the [sqlite3_changes()] interface and the 1379** [count_changes pragma]. 1380** 1381** Requirements: 1382** [H12261] [H12263] 1383** 1384** If a separate thread makes changes on the same database connection 1385** while [sqlite3_total_changes()] is running then the value 1386** returned is unpredictable and not meaningful. 1387*/ 1388int sqlite3_total_changes(sqlite3*); 1389 1390/* 1391** CAPI3REF: Interrupt A Long-Running Query {H12270} <S30500> 1392** 1393** This function causes any pending database operation to abort and 1394** return at its earliest opportunity. This routine is typically 1395** called in response to a user action such as pressing "Cancel" 1396** or Ctrl-C where the user wants a long query operation to halt 1397** immediately. 1398** 1399** It is safe to call this routine from a thread different from the 1400** thread that is currently running the database operation. But it 1401** is not safe to call this routine with a [database connection] that 1402** is closed or might close before sqlite3_interrupt() returns. 1403** 1404** If an SQL operation is very nearly finished at the time when 1405** sqlite3_interrupt() is called, then it might not have an opportunity 1406** to be interrupted and might continue to completion. 1407** 1408** An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1409** If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1410** that is inside an explicit transaction, then the entire transaction 1411** will be rolled back automatically. 1412** 1413** The sqlite3_interrupt(D) call is in effect until all currently running 1414** SQL statements on [database connection] D complete. Any new SQL statements 1415** that are started after the sqlite3_interrupt() call and before the 1416** running statements reaches zero are interrupted as if they had been 1417** running prior to the sqlite3_interrupt() call. New SQL statements 1418** that are started after the running statement count reaches zero are 1419** not effected by the sqlite3_interrupt(). 1420** A call to sqlite3_interrupt(D) that occurs when there are no running 1421** SQL statements is a no-op and has no effect on SQL statements 1422** that are started after the sqlite3_interrupt() call returns. 1423** 1424** Requirements: 1425** [H12271] [H12272] 1426** 1427** If the database connection closes while [sqlite3_interrupt()] 1428** is running then bad things will likely happen. 1429*/ 1430void sqlite3_interrupt(sqlite3*); 1431 1432/* 1433** CAPI3REF: Determine If An SQL Statement Is Complete {H10510} <S70200> 1434** 1435** These routines are useful during command-line input to determine if the 1436** currently entered text seems to form a complete SQL statement or 1437** if additional input is needed before sending the text into 1438** SQLite for parsing. These routines return 1 if the input string 1439** appears to be a complete SQL statement. A statement is judged to be 1440** complete if it ends with a semicolon token and is not a prefix of a 1441** well-formed CREATE TRIGGER statement. Semicolons that are embedded within 1442** string literals or quoted identifier names or comments are not 1443** independent tokens (they are part of the token in which they are 1444** embedded) and thus do not count as a statement terminator. Whitespace 1445** and comments that follow the final semicolon are ignored. 1446** 1447** These routines return 0 if the statement is incomplete. If a 1448** memory allocation fails, then SQLITE_NOMEM is returned. 1449** 1450** These routines do not parse the SQL statements thus 1451** will not detect syntactically incorrect SQL. 1452** 1453** If SQLite has not been initialized using [sqlite3_initialize()] prior 1454** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1455** automatically by sqlite3_complete16(). If that initialization fails, 1456** then the return value from sqlite3_complete16() will be non-zero 1457** regardless of whether or not the input SQL is complete. 1458** 1459** Requirements: [H10511] [H10512] 1460** 1461** The input to [sqlite3_complete()] must be a zero-terminated 1462** UTF-8 string. 1463** 1464** The input to [sqlite3_complete16()] must be a zero-terminated 1465** UTF-16 string in native byte order. 1466*/ 1467int sqlite3_complete(const char *sql); 1468int sqlite3_complete16(const void *sql); 1469 1470/* 1471** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors {H12310} <S40400> 1472** 1473** This routine sets a callback function that might be invoked whenever 1474** an attempt is made to open a database table that another thread 1475** or process has locked. 1476** 1477** If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1478** is returned immediately upon encountering the lock. If the busy callback 1479** is not NULL, then the callback will be invoked with two arguments. 1480** 1481** The first argument to the handler is a copy of the void* pointer which 1482** is the third argument to sqlite3_busy_handler(). The second argument to 1483** the handler callback is the number of times that the busy handler has 1484** been invoked for this locking event. If the 1485** busy callback returns 0, then no additional attempts are made to 1486** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1487** If the callback returns non-zero, then another attempt 1488** is made to open the database for reading and the cycle repeats. 1489** 1490** The presence of a busy handler does not guarantee that it will be invoked 1491** when there is lock contention. If SQLite determines that invoking the busy 1492** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1493** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1494** Consider a scenario where one process is holding a read lock that 1495** it is trying to promote to a reserved lock and 1496** a second process is holding a reserved lock that it is trying 1497** to promote to an exclusive lock. The first process cannot proceed 1498** because it is blocked by the second and the second process cannot 1499** proceed because it is blocked by the first. If both processes 1500** invoke the busy handlers, neither will make any progress. Therefore, 1501** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1502** will induce the first process to release its read lock and allow 1503** the second process to proceed. 1504** 1505** The default busy callback is NULL. 1506** 1507** The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1508** when SQLite is in the middle of a large transaction where all the 1509** changes will not fit into the in-memory cache. SQLite will 1510** already hold a RESERVED lock on the database file, but it needs 1511** to promote this lock to EXCLUSIVE so that it can spill cache 1512** pages into the database file without harm to concurrent 1513** readers. If it is unable to promote the lock, then the in-memory 1514** cache will be left in an inconsistent state and so the error 1515** code is promoted from the relatively benign [SQLITE_BUSY] to 1516** the more severe [SQLITE_IOERR_BLOCKED]. This error code promotion 1517** forces an automatic rollback of the changes. See the 1518** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1519** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1520** this is important. 1521** 1522** There can only be a single busy handler defined for each 1523** [database connection]. Setting a new busy handler clears any 1524** previously set handler. Note that calling [sqlite3_busy_timeout()] 1525** will also set or clear the busy handler. 1526** 1527** The busy callback should not take any actions which modify the 1528** database connection that invoked the busy handler. Any such actions 1529** result in undefined behavior. 1530** 1531** Requirements: 1532** [H12311] [H12312] [H12314] [H12316] [H12318] 1533** 1534** A busy handler must not close the database connection 1535** or [prepared statement] that invoked the busy handler. 1536*/ 1537int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1538 1539/* 1540** CAPI3REF: Set A Busy Timeout {H12340} <S40410> 1541** 1542** This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1543** for a specified amount of time when a table is locked. The handler 1544** will sleep multiple times until at least "ms" milliseconds of sleeping 1545** have accumulated. {H12343} After "ms" milliseconds of sleeping, 1546** the handler returns 0 which causes [sqlite3_step()] to return 1547** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1548** 1549** Calling this routine with an argument less than or equal to zero 1550** turns off all busy handlers. 1551** 1552** There can only be a single busy handler for a particular 1553** [database connection] any any given moment. If another busy handler 1554** was defined (using [sqlite3_busy_handler()]) prior to calling 1555** this routine, that other busy handler is cleared. 1556** 1557** Requirements: 1558** [H12341] [H12343] [H12344] 1559*/ 1560int sqlite3_busy_timeout(sqlite3*, int ms); 1561 1562/* 1563** CAPI3REF: Convenience Routines For Running Queries {H12370} <S10000> 1564** 1565** Definition: A <b>result table</b> is memory data structure created by the 1566** [sqlite3_get_table()] interface. A result table records the 1567** complete query results from one or more queries. 1568** 1569** The table conceptually has a number of rows and columns. But 1570** these numbers are not part of the result table itself. These 1571** numbers are obtained separately. Let N be the number of rows 1572** and M be the number of columns. 1573** 1574** A result table is an array of pointers to zero-terminated UTF-8 strings. 1575** There are (N+1)*M elements in the array. The first M pointers point 1576** to zero-terminated strings that contain the names of the columns. 1577** The remaining entries all point to query results. NULL values result 1578** in NULL pointers. All other values are in their UTF-8 zero-terminated 1579** string representation as returned by [sqlite3_column_text()]. 1580** 1581** A result table might consist of one or more memory allocations. 1582** It is not safe to pass a result table directly to [sqlite3_free()]. 1583** A result table should be deallocated using [sqlite3_free_table()]. 1584** 1585** As an example of the result table format, suppose a query result 1586** is as follows: 1587** 1588** <blockquote><pre> 1589** Name | Age 1590** ----------------------- 1591** Alice | 43 1592** Bob | 28 1593** Cindy | 21 1594** </pre></blockquote> 1595** 1596** There are two column (M==2) and three rows (N==3). Thus the 1597** result table has 8 entries. Suppose the result table is stored 1598** in an array names azResult. Then azResult holds this content: 1599** 1600** <blockquote><pre> 1601** azResult[0] = "Name"; 1602** azResult[1] = "Age"; 1603** azResult[2] = "Alice"; 1604** azResult[3] = "43"; 1605** azResult[4] = "Bob"; 1606** azResult[5] = "28"; 1607** azResult[6] = "Cindy"; 1608** azResult[7] = "21"; 1609** </pre></blockquote> 1610** 1611** The sqlite3_get_table() function evaluates one or more 1612** semicolon-separated SQL statements in the zero-terminated UTF-8 1613** string of its 2nd parameter. It returns a result table to the 1614** pointer given in its 3rd parameter. 1615** 1616** After the calling function has finished using the result, it should 1617** pass the pointer to the result table to sqlite3_free_table() in order to 1618** release the memory that was malloced. Because of the way the 1619** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1620** function must not try to call [sqlite3_free()] directly. Only 1621** [sqlite3_free_table()] is able to release the memory properly and safely. 1622** 1623** The sqlite3_get_table() interface is implemented as a wrapper around 1624** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 1625** to any internal data structures of SQLite. It uses only the public 1626** interface defined here. As a consequence, errors that occur in the 1627** wrapper layer outside of the internal [sqlite3_exec()] call are not 1628** reflected in subsequent calls to [sqlite3_errcode()] or [sqlite3_errmsg()]. 1629** 1630** Requirements: 1631** [H12371] [H12373] [H12374] [H12376] [H12379] [H12382] 1632*/ 1633int sqlite3_get_table( 1634 sqlite3 *db, /* An open database */ 1635 const char *zSql, /* SQL to be evaluated */ 1636 char ***pazResult, /* Results of the query */ 1637 int *pnRow, /* Number of result rows written here */ 1638 int *pnColumn, /* Number of result columns written here */ 1639 char **pzErrmsg /* Error msg written here */ 1640); 1641void sqlite3_free_table(char **result); 1642 1643/* 1644** CAPI3REF: Formatted String Printing Functions {H17400} <S70000><S20000> 1645** 1646** These routines are work-alikes of the "printf()" family of functions 1647** from the standard C library. 1648** 1649** The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 1650** results into memory obtained from [sqlite3_malloc()]. 1651** The strings returned by these two routines should be 1652** released by [sqlite3_free()]. Both routines return a 1653** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 1654** memory to hold the resulting string. 1655** 1656** In sqlite3_snprintf() routine is similar to "snprintf()" from 1657** the standard C library. The result is written into the 1658** buffer supplied as the second parameter whose size is given by 1659** the first parameter. Note that the order of the 1660** first two parameters is reversed from snprintf(). This is an 1661** historical accident that cannot be fixed without breaking 1662** backwards compatibility. Note also that sqlite3_snprintf() 1663** returns a pointer to its buffer instead of the number of 1664** characters actually written into the buffer. We admit that 1665** the number of characters written would be a more useful return 1666** value but we cannot change the implementation of sqlite3_snprintf() 1667** now without breaking compatibility. 1668** 1669** As long as the buffer size is greater than zero, sqlite3_snprintf() 1670** guarantees that the buffer is always zero-terminated. The first 1671** parameter "n" is the total size of the buffer, including space for 1672** the zero terminator. So the longest string that can be completely 1673** written will be n-1 characters. 1674** 1675** These routines all implement some additional formatting 1676** options that are useful for constructing SQL statements. 1677** All of the usual printf() formatting options apply. In addition, there 1678** is are "%q", "%Q", and "%z" options. 1679** 1680** The %q option works like %s in that it substitutes a null-terminated 1681** string from the argument list. But %q also doubles every '\'' character. 1682** %q is designed for use inside a string literal. By doubling each '\'' 1683** character it escapes that character and allows it to be inserted into 1684** the string. 1685** 1686** For example, assume the string variable zText contains text as follows: 1687** 1688** <blockquote><pre> 1689** char *zText = "It's a happy day!"; 1690** </pre></blockquote> 1691** 1692** One can use this text in an SQL statement as follows: 1693** 1694** <blockquote><pre> 1695** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 1696** sqlite3_exec(db, zSQL, 0, 0, 0); 1697** sqlite3_free(zSQL); 1698** </pre></blockquote> 1699** 1700** Because the %q format string is used, the '\'' character in zText 1701** is escaped and the SQL generated is as follows: 1702** 1703** <blockquote><pre> 1704** INSERT INTO table1 VALUES('It''s a happy day!') 1705** </pre></blockquote> 1706** 1707** This is correct. Had we used %s instead of %q, the generated SQL 1708** would have looked like this: 1709** 1710** <blockquote><pre> 1711** INSERT INTO table1 VALUES('It's a happy day!'); 1712** </pre></blockquote> 1713** 1714** This second example is an SQL syntax error. As a general rule you should 1715** always use %q instead of %s when inserting text into a string literal. 1716** 1717** The %Q option works like %q except it also adds single quotes around 1718** the outside of the total string. Additionally, if the parameter in the 1719** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 1720** single quotes) in place of the %Q option. So, for example, one could say: 1721** 1722** <blockquote><pre> 1723** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 1724** sqlite3_exec(db, zSQL, 0, 0, 0); 1725** sqlite3_free(zSQL); 1726** </pre></blockquote> 1727** 1728** The code above will render a correct SQL statement in the zSQL 1729** variable even if the zText variable is a NULL pointer. 1730** 1731** The "%z" formatting option works exactly like "%s" with the 1732** addition that after the string has been read and copied into 1733** the result, [sqlite3_free()] is called on the input string. {END} 1734** 1735** Requirements: 1736** [H17403] [H17406] [H17407] 1737*/ 1738char *sqlite3_mprintf(const char*,...); 1739char *sqlite3_vmprintf(const char*, va_list); 1740char *sqlite3_snprintf(int,char*,const char*, ...); 1741 1742/* 1743** CAPI3REF: Memory Allocation Subsystem {H17300} <S20000> 1744** 1745** The SQLite core uses these three routines for all of its own 1746** internal memory allocation needs. "Core" in the previous sentence 1747** does not include operating-system specific VFS implementation. The 1748** Windows VFS uses native malloc() and free() for some operations. 1749** 1750** The sqlite3_malloc() routine returns a pointer to a block 1751** of memory at least N bytes in length, where N is the parameter. 1752** If sqlite3_malloc() is unable to obtain sufficient free 1753** memory, it returns a NULL pointer. If the parameter N to 1754** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 1755** a NULL pointer. 1756** 1757** Calling sqlite3_free() with a pointer previously returned 1758** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 1759** that it might be reused. The sqlite3_free() routine is 1760** a no-op if is called with a NULL pointer. Passing a NULL pointer 1761** to sqlite3_free() is harmless. After being freed, memory 1762** should neither be read nor written. Even reading previously freed 1763** memory might result in a segmentation fault or other severe error. 1764** Memory corruption, a segmentation fault, or other severe error 1765** might result if sqlite3_free() is called with a non-NULL pointer that 1766** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 1767** 1768** The sqlite3_realloc() interface attempts to resize a 1769** prior memory allocation to be at least N bytes, where N is the 1770** second parameter. The memory allocation to be resized is the first 1771** parameter. If the first parameter to sqlite3_realloc() 1772** is a NULL pointer then its behavior is identical to calling 1773** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 1774** If the second parameter to sqlite3_realloc() is zero or 1775** negative then the behavior is exactly the same as calling 1776** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 1777** sqlite3_realloc() returns a pointer to a memory allocation 1778** of at least N bytes in size or NULL if sufficient memory is unavailable. 1779** If M is the size of the prior allocation, then min(N,M) bytes 1780** of the prior allocation are copied into the beginning of buffer returned 1781** by sqlite3_realloc() and the prior allocation is freed. 1782** If sqlite3_realloc() returns NULL, then the prior allocation 1783** is not freed. 1784** 1785** The memory returned by sqlite3_malloc() and sqlite3_realloc() 1786** is always aligned to at least an 8 byte boundary. {END} 1787** 1788** The default implementation of the memory allocation subsystem uses 1789** the malloc(), realloc() and free() provided by the standard C library. 1790** {H17382} However, if SQLite is compiled with the 1791** SQLITE_MEMORY_SIZE=<i>NNN</i> C preprocessor macro (where <i>NNN</i> 1792** is an integer), then SQLite create a static array of at least 1793** <i>NNN</i> bytes in size and uses that array for all of its dynamic 1794** memory allocation needs. {END} Additional memory allocator options 1795** may be added in future releases. 1796** 1797** In SQLite version 3.5.0 and 3.5.1, it was possible to define 1798** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 1799** implementation of these routines to be omitted. That capability 1800** is no longer provided. Only built-in memory allocators can be used. 1801** 1802** The Windows OS interface layer calls 1803** the system malloc() and free() directly when converting 1804** filenames between the UTF-8 encoding used by SQLite 1805** and whatever filename encoding is used by the particular Windows 1806** installation. Memory allocation errors are detected, but 1807** they are reported back as [SQLITE_CANTOPEN] or 1808** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 1809** 1810** Requirements: 1811** [H17303] [H17304] [H17305] [H17306] [H17310] [H17312] [H17315] [H17318] 1812** [H17321] [H17322] [H17323] 1813** 1814** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 1815** must be either NULL or else pointers obtained from a prior 1816** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 1817** not yet been released. 1818** 1819** The application must not read or write any part of 1820** a block of memory after it has been released using 1821** [sqlite3_free()] or [sqlite3_realloc()]. 1822*/ 1823void *sqlite3_malloc(int); 1824void *sqlite3_realloc(void*, int); 1825void sqlite3_free(void*); 1826 1827/* 1828** CAPI3REF: Memory Allocator Statistics {H17370} <S30210> 1829** 1830** SQLite provides these two interfaces for reporting on the status 1831** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 1832** routines, which form the built-in memory allocation subsystem. 1833** 1834** Requirements: 1835** [H17371] [H17373] [H17374] [H17375] 1836*/ 1837sqlite3_int64 sqlite3_memory_used(void); 1838sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 1839 1840/* 1841** CAPI3REF: Pseudo-Random Number Generator {H17390} <S20000> 1842** 1843** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 1844** select random [ROWID | ROWIDs] when inserting new records into a table that 1845** already uses the largest possible [ROWID]. The PRNG is also used for 1846** the build-in random() and randomblob() SQL functions. This interface allows 1847** applications to access the same PRNG for other purposes. 1848** 1849** A call to this routine stores N bytes of randomness into buffer P. 1850** 1851** The first time this routine is invoked (either internally or by 1852** the application) the PRNG is seeded using randomness obtained 1853** from the xRandomness method of the default [sqlite3_vfs] object. 1854** On all subsequent invocations, the pseudo-randomness is generated 1855** internally and without recourse to the [sqlite3_vfs] xRandomness 1856** method. 1857** 1858** Requirements: 1859** [H17392] 1860*/ 1861void sqlite3_randomness(int N, void *P); 1862 1863/* 1864** CAPI3REF: Compile-Time Authorization Callbacks {H12500} <S70100> 1865** 1866** This routine registers a authorizer callback with a particular 1867** [database connection], supplied in the first argument. 1868** The authorizer callback is invoked as SQL statements are being compiled 1869** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 1870** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. At various 1871** points during the compilation process, as logic is being created 1872** to perform various actions, the authorizer callback is invoked to 1873** see if those actions are allowed. The authorizer callback should 1874** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 1875** specific action but allow the SQL statement to continue to be 1876** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 1877** rejected with an error. If the authorizer callback returns 1878** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 1879** then the [sqlite3_prepare_v2()] or equivalent call that triggered 1880** the authorizer will fail with an error message. 1881** 1882** When the callback returns [SQLITE_OK], that means the operation 1883** requested is ok. When the callback returns [SQLITE_DENY], the 1884** [sqlite3_prepare_v2()] or equivalent call that triggered the 1885** authorizer will fail with an error message explaining that 1886** access is denied. 1887** 1888** The first parameter to the authorizer callback is a copy of the third 1889** parameter to the sqlite3_set_authorizer() interface. The second parameter 1890** to the callback is an integer [SQLITE_COPY | action code] that specifies 1891** the particular action to be authorized. The third through sixth parameters 1892** to the callback are zero-terminated strings that contain additional 1893** details about the action to be authorized. 1894** 1895** If the action code is [SQLITE_READ] 1896** and the callback returns [SQLITE_IGNORE] then the 1897** [prepared statement] statement is constructed to substitute 1898** a NULL value in place of the table column that would have 1899** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 1900** return can be used to deny an untrusted user access to individual 1901** columns of a table. 1902** If the action code is [SQLITE_DELETE] and the callback returns 1903** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 1904** [truncate optimization] is disabled and all rows are deleted individually. 1905** 1906** An authorizer is used when [sqlite3_prepare | preparing] 1907** SQL statements from an untrusted source, to ensure that the SQL statements 1908** do not try to access data they are not allowed to see, or that they do not 1909** try to execute malicious statements that damage the database. For 1910** example, an application may allow a user to enter arbitrary 1911** SQL queries for evaluation by a database. But the application does 1912** not want the user to be able to make arbitrary changes to the 1913** database. An authorizer could then be put in place while the 1914** user-entered SQL is being [sqlite3_prepare | prepared] that 1915** disallows everything except [SELECT] statements. 1916** 1917** Applications that need to process SQL from untrusted sources 1918** might also consider lowering resource limits using [sqlite3_limit()] 1919** and limiting database size using the [max_page_count] [PRAGMA] 1920** in addition to using an authorizer. 1921** 1922** Only a single authorizer can be in place on a database connection 1923** at a time. Each call to sqlite3_set_authorizer overrides the 1924** previous call. Disable the authorizer by installing a NULL callback. 1925** The authorizer is disabled by default. 1926** 1927** The authorizer callback must not do anything that will modify 1928** the database connection that invoked the authorizer callback. 1929** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 1930** database connections for the meaning of "modify" in this paragraph. 1931** 1932** When [sqlite3_prepare_v2()] is used to prepare a statement, the 1933** statement might be re-prepared during [sqlite3_step()] due to a 1934** schema change. Hence, the application should ensure that the 1935** correct authorizer callback remains in place during the [sqlite3_step()]. 1936** 1937** Note that the authorizer callback is invoked only during 1938** [sqlite3_prepare()] or its variants. Authorization is not 1939** performed during statement evaluation in [sqlite3_step()], unless 1940** as stated in the previous paragraph, sqlite3_step() invokes 1941** sqlite3_prepare_v2() to reprepare a statement after a schema change. 1942** 1943** Requirements: 1944** [H12501] [H12502] [H12503] [H12504] [H12505] [H12506] [H12507] [H12510] 1945** [H12511] [H12512] [H12520] [H12521] [H12522] 1946*/ 1947int sqlite3_set_authorizer( 1948 sqlite3*, 1949 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 1950 void *pUserData 1951); 1952 1953/* 1954** CAPI3REF: Authorizer Return Codes {H12590} <H12500> 1955** 1956** The [sqlite3_set_authorizer | authorizer callback function] must 1957** return either [SQLITE_OK] or one of these two constants in order 1958** to signal SQLite whether or not the action is permitted. See the 1959** [sqlite3_set_authorizer | authorizer documentation] for additional 1960** information. 1961*/ 1962#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 1963#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 1964 1965/* 1966** CAPI3REF: Authorizer Action Codes {H12550} <H12500> 1967** 1968** The [sqlite3_set_authorizer()] interface registers a callback function 1969** that is invoked to authorize certain SQL statement actions. The 1970** second parameter to the callback is an integer code that specifies 1971** what action is being authorized. These are the integer action codes that 1972** the authorizer callback may be passed. 1973** 1974** These action code values signify what kind of operation is to be 1975** authorized. The 3rd and 4th parameters to the authorization 1976** callback function will be parameters or NULL depending on which of these 1977** codes is used as the second parameter. The 5th parameter to the 1978** authorizer callback is the name of the database ("main", "temp", 1979** etc.) if applicable. The 6th parameter to the authorizer callback 1980** is the name of the inner-most trigger or view that is responsible for 1981** the access attempt or NULL if this access attempt is directly from 1982** top-level SQL code. 1983** 1984** Requirements: 1985** [H12551] [H12552] [H12553] [H12554] 1986*/ 1987/******************************************* 3rd ************ 4th ***********/ 1988#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 1989#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 1990#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 1991#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 1992#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 1993#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 1994#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 1995#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 1996#define SQLITE_DELETE 9 /* Table Name NULL */ 1997#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 1998#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 1999#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2000#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2001#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2002#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2003#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2004#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2005#define SQLITE_INSERT 18 /* Table Name NULL */ 2006#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2007#define SQLITE_READ 20 /* Table Name Column Name */ 2008#define SQLITE_SELECT 21 /* NULL NULL */ 2009#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2010#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2011#define SQLITE_ATTACH 24 /* Filename NULL */ 2012#define SQLITE_DETACH 25 /* Database Name NULL */ 2013#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2014#define SQLITE_REINDEX 27 /* Index Name NULL */ 2015#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2016#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2017#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2018#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2019#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2020#define SQLITE_COPY 0 /* No longer used */ 2021 2022/* 2023** CAPI3REF: Tracing And Profiling Functions {H12280} <S60400> 2024** EXPERIMENTAL 2025** 2026** These routines register callback functions that can be used for 2027** tracing and profiling the execution of SQL statements. 2028** 2029** The callback function registered by sqlite3_trace() is invoked at 2030** various times when an SQL statement is being run by [sqlite3_step()]. 2031** The callback returns a UTF-8 rendering of the SQL statement text 2032** as the statement first begins executing. Additional callbacks occur 2033** as each triggered subprogram is entered. The callbacks for triggers 2034** contain a UTF-8 SQL comment that identifies the trigger. 2035** 2036** The callback function registered by sqlite3_profile() is invoked 2037** as each SQL statement finishes. The profile callback contains 2038** the original statement text and an estimate of wall-clock time 2039** of how long that statement took to run. 2040** 2041** Requirements: 2042** [H12281] [H12282] [H12283] [H12284] [H12285] [H12287] [H12288] [H12289] 2043** [H12290] 2044*/ 2045SQLITE_EXPERIMENTAL void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2046SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2047 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2048 2049/* 2050** CAPI3REF: Query Progress Callbacks {H12910} <S60400> 2051** 2052** This routine configures a callback function - the 2053** progress callback - that is invoked periodically during long 2054** running calls to [sqlite3_exec()], [sqlite3_step()] and 2055** [sqlite3_get_table()]. An example use for this 2056** interface is to keep a GUI updated during a large query. 2057** 2058** If the progress callback returns non-zero, the operation is 2059** interrupted. This feature can be used to implement a 2060** "Cancel" button on a GUI progress dialog box. 2061** 2062** The progress handler must not do anything that will modify 2063** the database connection that invoked the progress handler. 2064** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2065** database connections for the meaning of "modify" in this paragraph. 2066** 2067** Requirements: 2068** [H12911] [H12912] [H12913] [H12914] [H12915] [H12916] [H12917] [H12918] 2069** 2070*/ 2071void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2072 2073/* 2074** CAPI3REF: Opening A New Database Connection {H12700} <S40200> 2075** 2076** These routines open an SQLite database file whose name is given by the 2077** filename argument. The filename argument is interpreted as UTF-8 for 2078** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2079** order for sqlite3_open16(). A [database connection] handle is usually 2080** returned in *ppDb, even if an error occurs. The only exception is that 2081** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2082** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2083** object. If the database is opened (and/or created) successfully, then 2084** [SQLITE_OK] is returned. Otherwise an [error code] is returned. The 2085** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2086** an English language description of the error. 2087** 2088** The default encoding for the database will be UTF-8 if 2089** sqlite3_open() or sqlite3_open_v2() is called and 2090** UTF-16 in the native byte order if sqlite3_open16() is used. 2091** 2092** Whether or not an error occurs when it is opened, resources 2093** associated with the [database connection] handle should be released by 2094** passing it to [sqlite3_close()] when it is no longer required. 2095** 2096** The sqlite3_open_v2() interface works like sqlite3_open() 2097** except that it accepts two additional parameters for additional control 2098** over the new database connection. The flags parameter can take one of 2099** the following three values, optionally combined with the 2100** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2101** and/or [SQLITE_OPEN_PRIVATECACHE] flags: 2102** 2103** <dl> 2104** <dt>[SQLITE_OPEN_READONLY]</dt> 2105** <dd>The database is opened in read-only mode. If the database does not 2106** already exist, an error is returned.</dd> 2107** 2108** <dt>[SQLITE_OPEN_READWRITE]</dt> 2109** <dd>The database is opened for reading and writing if possible, or reading 2110** only if the file is write protected by the operating system. In either 2111** case the database must already exist, otherwise an error is returned.</dd> 2112** 2113** <dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2114** <dd>The database is opened for reading and writing, and is creates it if 2115** it does not already exist. This is the behavior that is always used for 2116** sqlite3_open() and sqlite3_open16().</dd> 2117** </dl> 2118** 2119** If the 3rd parameter to sqlite3_open_v2() is not one of the 2120** combinations shown above or one of the combinations shown above combined 2121** with the [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], 2122** [SQLITE_OPEN_SHAREDCACHE] and/or [SQLITE_OPEN_SHAREDCACHE] flags, 2123** then the behavior is undefined. 2124** 2125** If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2126** opens in the multi-thread [threading mode] as long as the single-thread 2127** mode has not been set at compile-time or start-time. If the 2128** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2129** in the serialized [threading mode] unless single-thread was 2130** previously selected at compile-time or start-time. 2131** The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2132** eligible to use [shared cache mode], regardless of whether or not shared 2133** cache is enabled using [sqlite3_enable_shared_cache()]. The 2134** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2135** participate in [shared cache mode] even if it is enabled. 2136** 2137** If the filename is ":memory:", then a private, temporary in-memory database 2138** is created for the connection. This in-memory database will vanish when 2139** the database connection is closed. Future versions of SQLite might 2140** make use of additional special filenames that begin with the ":" character. 2141** It is recommended that when a database filename actually does begin with 2142** a ":" character you should prefix the filename with a pathname such as 2143** "./" to avoid ambiguity. 2144** 2145** If the filename is an empty string, then a private, temporary 2146** on-disk database will be created. This private database will be 2147** automatically deleted as soon as the database connection is closed. 2148** 2149** The fourth parameter to sqlite3_open_v2() is the name of the 2150** [sqlite3_vfs] object that defines the operating system interface that 2151** the new database connection should use. If the fourth parameter is 2152** a NULL pointer then the default [sqlite3_vfs] object is used. 2153** 2154** <b>Note to Windows users:</b> The encoding used for the filename argument 2155** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2156** codepage is currently defined. Filenames containing international 2157** characters must be converted to UTF-8 prior to passing them into 2158** sqlite3_open() or sqlite3_open_v2(). 2159** 2160** Requirements: 2161** [H12701] [H12702] [H12703] [H12704] [H12706] [H12707] [H12709] [H12711] 2162** [H12712] [H12713] [H12714] [H12717] [H12719] [H12721] [H12723] 2163*/ 2164int sqlite3_open( 2165 const char *filename, /* Database filename (UTF-8) */ 2166 sqlite3 **ppDb /* OUT: SQLite db handle */ 2167); 2168int sqlite3_open16( 2169 const void *filename, /* Database filename (UTF-16) */ 2170 sqlite3 **ppDb /* OUT: SQLite db handle */ 2171); 2172int sqlite3_open_v2( 2173 const char *filename, /* Database filename (UTF-8) */ 2174 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2175 int flags, /* Flags */ 2176 const char *zVfs /* Name of VFS module to use */ 2177); 2178 2179/* 2180** CAPI3REF: Error Codes And Messages {H12800} <S60200> 2181** 2182** The sqlite3_errcode() interface returns the numeric [result code] or 2183** [extended result code] for the most recent failed sqlite3_* API call 2184** associated with a [database connection]. If a prior API call failed 2185** but the most recent API call succeeded, the return value from 2186** sqlite3_errcode() is undefined. The sqlite3_extended_errcode() 2187** interface is the same except that it always returns the 2188** [extended result code] even when extended result codes are 2189** disabled. 2190** 2191** The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2192** text that describes the error, as either UTF-8 or UTF-16 respectively. 2193** Memory to hold the error message string is managed internally. 2194** The application does not need to worry about freeing the result. 2195** However, the error string might be overwritten or deallocated by 2196** subsequent calls to other SQLite interface functions. 2197** 2198** When the serialized [threading mode] is in use, it might be the 2199** case that a second error occurs on a separate thread in between 2200** the time of the first error and the call to these interfaces. 2201** When that happens, the second error will be reported since these 2202** interfaces always report the most recent result. To avoid 2203** this, each thread can obtain exclusive use of the [database connection] D 2204** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2205** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2206** all calls to the interfaces listed here are completed. 2207** 2208** If an interface fails with SQLITE_MISUSE, that means the interface 2209** was invoked incorrectly by the application. In that case, the 2210** error code and message may or may not be set. 2211** 2212** Requirements: 2213** [H12801] [H12802] [H12803] [H12807] [H12808] [H12809] 2214*/ 2215int sqlite3_errcode(sqlite3 *db); 2216int sqlite3_extended_errcode(sqlite3 *db); 2217const char *sqlite3_errmsg(sqlite3*); 2218const void *sqlite3_errmsg16(sqlite3*); 2219 2220/* 2221** CAPI3REF: SQL Statement Object {H13000} <H13010> 2222** KEYWORDS: {prepared statement} {prepared statements} 2223** 2224** An instance of this object represents a single SQL statement. 2225** This object is variously known as a "prepared statement" or a 2226** "compiled SQL statement" or simply as a "statement". 2227** 2228** The life of a statement object goes something like this: 2229** 2230** <ol> 2231** <li> Create the object using [sqlite3_prepare_v2()] or a related 2232** function. 2233** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2234** interfaces. 2235** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2236** <li> Reset the statement using [sqlite3_reset()] then go back 2237** to step 2. Do this zero or more times. 2238** <li> Destroy the object using [sqlite3_finalize()]. 2239** </ol> 2240** 2241** Refer to documentation on individual methods above for additional 2242** information. 2243*/ 2244typedef struct sqlite3_stmt sqlite3_stmt; 2245 2246/* 2247** CAPI3REF: Run-time Limits {H12760} <S20600> 2248** 2249** This interface allows the size of various constructs to be limited 2250** on a connection by connection basis. The first parameter is the 2251** [database connection] whose limit is to be set or queried. The 2252** second parameter is one of the [limit categories] that define a 2253** class of constructs to be size limited. The third parameter is the 2254** new limit for that construct. The function returns the old limit. 2255** 2256** If the new limit is a negative number, the limit is unchanged. 2257** For the limit category of SQLITE_LIMIT_XYZ there is a 2258** [limits | hard upper bound] 2259** set by a compile-time C preprocessor macro named 2260** [limits | SQLITE_MAX_XYZ]. 2261** (The "_LIMIT_" in the name is changed to "_MAX_".) 2262** Attempts to increase a limit above its hard upper bound are 2263** silently truncated to the hard upper limit. 2264** 2265** Run time limits are intended for use in applications that manage 2266** both their own internal database and also databases that are controlled 2267** by untrusted external sources. An example application might be a 2268** web browser that has its own databases for storing history and 2269** separate databases controlled by JavaScript applications downloaded 2270** off the Internet. The internal databases can be given the 2271** large, default limits. Databases managed by external sources can 2272** be given much smaller limits designed to prevent a denial of service 2273** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2274** interface to further control untrusted SQL. The size of the database 2275** created by an untrusted script can be contained using the 2276** [max_page_count] [PRAGMA]. 2277** 2278** New run-time limit categories may be added in future releases. 2279** 2280** Requirements: 2281** [H12762] [H12766] [H12769] 2282*/ 2283int sqlite3_limit(sqlite3*, int id, int newVal); 2284 2285/* 2286** CAPI3REF: Run-Time Limit Categories {H12790} <H12760> 2287** KEYWORDS: {limit category} {*limit categories} 2288** 2289** These constants define various performance limits 2290** that can be lowered at run-time using [sqlite3_limit()]. 2291** The synopsis of the meanings of the various limits is shown below. 2292** Additional information is available at [limits | Limits in SQLite]. 2293** 2294** <dl> 2295** <dt>SQLITE_LIMIT_LENGTH</dt> 2296** <dd>The maximum size of any string or BLOB or table row.<dd> 2297** 2298** <dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2299** <dd>The maximum length of an SQL statement.</dd> 2300** 2301** <dt>SQLITE_LIMIT_COLUMN</dt> 2302** <dd>The maximum number of columns in a table definition or in the 2303** result set of a [SELECT] or the maximum number of columns in an index 2304** or in an ORDER BY or GROUP BY clause.</dd> 2305** 2306** <dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2307** <dd>The maximum depth of the parse tree on any expression.</dd> 2308** 2309** <dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2310** <dd>The maximum number of terms in a compound SELECT statement.</dd> 2311** 2312** <dt>SQLITE_LIMIT_VDBE_OP</dt> 2313** <dd>The maximum number of instructions in a virtual machine program 2314** used to implement an SQL statement.</dd> 2315** 2316** <dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2317** <dd>The maximum number of arguments on a function.</dd> 2318** 2319** <dt>SQLITE_LIMIT_ATTACHED</dt> 2320** <dd>The maximum number of [ATTACH | attached databases].</dd> 2321** 2322** <dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2323** <dd>The maximum length of the pattern argument to the [LIKE] or 2324** [GLOB] operators.</dd> 2325** 2326** <dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2327** <dd>The maximum number of variables in an SQL statement that can 2328** be bound.</dd> 2329** 2330** <dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2331** <dd>The maximum depth of recursion for triggers.</dd> 2332** </dl> 2333*/ 2334#define SQLITE_LIMIT_LENGTH 0 2335#define SQLITE_LIMIT_SQL_LENGTH 1 2336#define SQLITE_LIMIT_COLUMN 2 2337#define SQLITE_LIMIT_EXPR_DEPTH 3 2338#define SQLITE_LIMIT_COMPOUND_SELECT 4 2339#define SQLITE_LIMIT_VDBE_OP 5 2340#define SQLITE_LIMIT_FUNCTION_ARG 6 2341#define SQLITE_LIMIT_ATTACHED 7 2342#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2343#define SQLITE_LIMIT_VARIABLE_NUMBER 9 2344#define SQLITE_LIMIT_TRIGGER_DEPTH 10 2345 2346/* 2347** CAPI3REF: Compiling An SQL Statement {H13010} <S10000> 2348** KEYWORDS: {SQL statement compiler} 2349** 2350** To execute an SQL query, it must first be compiled into a byte-code 2351** program using one of these routines. 2352** 2353** The first argument, "db", is a [database connection] obtained from a 2354** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2355** [sqlite3_open16()]. The database connection must not have been closed. 2356** 2357** The second argument, "zSql", is the statement to be compiled, encoded 2358** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2359** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2360** use UTF-16. 2361** 2362** If the nByte argument is less than zero, then zSql is read up to the 2363** first zero terminator. If nByte is non-negative, then it is the maximum 2364** number of bytes read from zSql. When nByte is non-negative, the 2365** zSql string ends at either the first '\000' or '\u0000' character or 2366** the nByte-th byte, whichever comes first. If the caller knows 2367** that the supplied string is nul-terminated, then there is a small 2368** performance advantage to be gained by passing an nByte parameter that 2369** is equal to the number of bytes in the input string <i>including</i> 2370** the nul-terminator bytes. 2371** 2372** If pzTail is not NULL then *pzTail is made to point to the first byte 2373** past the end of the first SQL statement in zSql. These routines only 2374** compile the first statement in zSql, so *pzTail is left pointing to 2375** what remains uncompiled. 2376** 2377** *ppStmt is left pointing to a compiled [prepared statement] that can be 2378** executed using [sqlite3_step()]. If there is an error, *ppStmt is set 2379** to NULL. If the input text contains no SQL (if the input is an empty 2380** string or a comment) then *ppStmt is set to NULL. 2381** The calling procedure is responsible for deleting the compiled 2382** SQL statement using [sqlite3_finalize()] after it has finished with it. 2383** ppStmt may not be NULL. 2384** 2385** On success, [SQLITE_OK] is returned, otherwise an [error code] is returned. 2386** 2387** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2388** recommended for all new programs. The two older interfaces are retained 2389** for backwards compatibility, but their use is discouraged. 2390** In the "v2" interfaces, the prepared statement 2391** that is returned (the [sqlite3_stmt] object) contains a copy of the 2392** original SQL text. This causes the [sqlite3_step()] interface to 2393** behave differently in three ways: 2394** 2395** <ol> 2396** <li> 2397** If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2398** always used to do, [sqlite3_step()] will automatically recompile the SQL 2399** statement and try to run it again. If the schema has changed in 2400** a way that makes the statement no longer valid, [sqlite3_step()] will still 2401** return [SQLITE_SCHEMA]. But unlike the legacy behavior, [SQLITE_SCHEMA] is 2402** now a fatal error. Calling [sqlite3_prepare_v2()] again will not make the 2403** error go away. Note: use [sqlite3_errmsg()] to find the text 2404** of the parsing error that results in an [SQLITE_SCHEMA] return. 2405** </li> 2406** 2407** <li> 2408** When an error occurs, [sqlite3_step()] will return one of the detailed 2409** [error codes] or [extended error codes]. The legacy behavior was that 2410** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2411** and you would have to make a second call to [sqlite3_reset()] in order 2412** to find the underlying cause of the problem. With the "v2" prepare 2413** interfaces, the underlying reason for the error is returned immediately. 2414** </li> 2415** 2416** <li> 2417** ^If the value of a [parameter | host parameter] in the WHERE clause might 2418** change the query plan for a statement, then the statement may be 2419** automatically recompiled (as if there had been a schema change) on the first 2420** [sqlite3_step()] call following any change to the 2421** [sqlite3_bind_text | bindings] of the [parameter]. 2422** </li> 2423** </ol> 2424** 2425** Requirements: 2426** [H13011] [H13012] [H13013] [H13014] [H13015] [H13016] [H13019] [H13021] 2427** 2428*/ 2429int sqlite3_prepare( 2430 sqlite3 *db, /* Database handle */ 2431 const char *zSql, /* SQL statement, UTF-8 encoded */ 2432 int nByte, /* Maximum length of zSql in bytes. */ 2433 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2434 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2435); 2436int sqlite3_prepare_v2( 2437 sqlite3 *db, /* Database handle */ 2438 const char *zSql, /* SQL statement, UTF-8 encoded */ 2439 int nByte, /* Maximum length of zSql in bytes. */ 2440 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2441 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2442); 2443int sqlite3_prepare16( 2444 sqlite3 *db, /* Database handle */ 2445 const void *zSql, /* SQL statement, UTF-16 encoded */ 2446 int nByte, /* Maximum length of zSql in bytes. */ 2447 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2448 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2449); 2450int sqlite3_prepare16_v2( 2451 sqlite3 *db, /* Database handle */ 2452 const void *zSql, /* SQL statement, UTF-16 encoded */ 2453 int nByte, /* Maximum length of zSql in bytes. */ 2454 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2455 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2456); 2457 2458/* 2459** CAPI3REF: Retrieving Statement SQL {H13100} <H13000> 2460** 2461** This interface can be used to retrieve a saved copy of the original 2462** SQL text used to create a [prepared statement] if that statement was 2463** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2464** 2465** Requirements: 2466** [H13101] [H13102] [H13103] 2467*/ 2468const char *sqlite3_sql(sqlite3_stmt *pStmt); 2469 2470/* 2471** CAPI3REF: Dynamically Typed Value Object {H15000} <S20200> 2472** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 2473** 2474** SQLite uses the sqlite3_value object to represent all values 2475** that can be stored in a database table. SQLite uses dynamic typing 2476** for the values it stores. Values stored in sqlite3_value objects 2477** can be integers, floating point values, strings, BLOBs, or NULL. 2478** 2479** An sqlite3_value object may be either "protected" or "unprotected". 2480** Some interfaces require a protected sqlite3_value. Other interfaces 2481** will accept either a protected or an unprotected sqlite3_value. 2482** Every interface that accepts sqlite3_value arguments specifies 2483** whether or not it requires a protected sqlite3_value. 2484** 2485** The terms "protected" and "unprotected" refer to whether or not 2486** a mutex is held. A internal mutex is held for a protected 2487** sqlite3_value object but no mutex is held for an unprotected 2488** sqlite3_value object. If SQLite is compiled to be single-threaded 2489** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 2490** or if SQLite is run in one of reduced mutex modes 2491** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 2492** then there is no distinction between protected and unprotected 2493** sqlite3_value objects and they can be used interchangeably. However, 2494** for maximum code portability it is recommended that applications 2495** still make the distinction between between protected and unprotected 2496** sqlite3_value objects even when not strictly required. 2497** 2498** The sqlite3_value objects that are passed as parameters into the 2499** implementation of [application-defined SQL functions] are protected. 2500** The sqlite3_value object returned by 2501** [sqlite3_column_value()] is unprotected. 2502** Unprotected sqlite3_value objects may only be used with 2503** [sqlite3_result_value()] and [sqlite3_bind_value()]. 2504** The [sqlite3_value_blob | sqlite3_value_type()] family of 2505** interfaces require protected sqlite3_value objects. 2506*/ 2507typedef struct Mem sqlite3_value; 2508 2509/* 2510** CAPI3REF: SQL Function Context Object {H16001} <S20200> 2511** 2512** The context in which an SQL function executes is stored in an 2513** sqlite3_context object. A pointer to an sqlite3_context object 2514** is always first parameter to [application-defined SQL functions]. 2515** The application-defined SQL function implementation will pass this 2516** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 2517** [sqlite3_aggregate_context()], [sqlite3_user_data()], 2518** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 2519** and/or [sqlite3_set_auxdata()]. 2520*/ 2521typedef struct sqlite3_context sqlite3_context; 2522 2523/* 2524** CAPI3REF: Binding Values To Prepared Statements {H13500} <S70300> 2525** KEYWORDS: {host parameter} {host parameters} {host parameter name} 2526** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 2527** 2528** In the SQL strings input to [sqlite3_prepare_v2()] and its variants, 2529** literals may be replaced by a [parameter] that matches one of following 2530** templates: 2531** 2532** <ul> 2533** <li> ? 2534** <li> ?NNN 2535** <li> :VVV 2536** <li> @VVV 2537** <li> $VVV 2538** </ul> 2539** 2540** In the templates above, NNN represents an integer literal, 2541** and VVV represents an alphanumeric identifer. The values of these 2542** parameters (also called "host parameter names" or "SQL parameters") 2543** can be set using the sqlite3_bind_*() routines defined here. 2544** 2545** The first argument to the sqlite3_bind_*() routines is always 2546** a pointer to the [sqlite3_stmt] object returned from 2547** [sqlite3_prepare_v2()] or its variants. 2548** 2549** The second argument is the index of the SQL parameter to be set. 2550** The leftmost SQL parameter has an index of 1. When the same named 2551** SQL parameter is used more than once, second and subsequent 2552** occurrences have the same index as the first occurrence. 2553** The index for named parameters can be looked up using the 2554** [sqlite3_bind_parameter_index()] API if desired. The index 2555** for "?NNN" parameters is the value of NNN. 2556** The NNN value must be between 1 and the [sqlite3_limit()] 2557** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 2558** 2559** The third argument is the value to bind to the parameter. 2560** 2561** In those routines that have a fourth argument, its value is the 2562** number of bytes in the parameter. To be clear: the value is the 2563** number of <u>bytes</u> in the value, not the number of characters. 2564** If the fourth parameter is negative, the length of the string is 2565** the number of bytes up to the first zero terminator. 2566** 2567** The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 2568** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 2569** string after SQLite has finished with it. If the fifth argument is 2570** the special value [SQLITE_STATIC], then SQLite assumes that the 2571** information is in static, unmanaged space and does not need to be freed. 2572** If the fifth argument has the value [SQLITE_TRANSIENT], then 2573** SQLite makes its own private copy of the data immediately, before 2574** the sqlite3_bind_*() routine returns. 2575** 2576** The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 2577** is filled with zeroes. A zeroblob uses a fixed amount of memory 2578** (just an integer to hold its size) while it is being processed. 2579** Zeroblobs are intended to serve as placeholders for BLOBs whose 2580** content is later written using 2581** [sqlite3_blob_open | incremental BLOB I/O] routines. 2582** A negative value for the zeroblob results in a zero-length BLOB. 2583** 2584** The sqlite3_bind_*() routines must be called after 2585** [sqlite3_prepare_v2()] (and its variants) or [sqlite3_reset()] and 2586** before [sqlite3_step()]. 2587** Bindings are not cleared by the [sqlite3_reset()] routine. 2588** Unbound parameters are interpreted as NULL. 2589** 2590** These routines return [SQLITE_OK] on success or an error code if 2591** anything goes wrong. [SQLITE_RANGE] is returned if the parameter 2592** index is out of range. [SQLITE_NOMEM] is returned if malloc() fails. 2593** [SQLITE_MISUSE] might be returned if these routines are called on a 2594** virtual machine that is the wrong state or which has already been finalized. 2595** Detection of misuse is unreliable. Applications should not depend 2596** on SQLITE_MISUSE returns. SQLITE_MISUSE is intended to indicate a 2597** a logic error in the application. Future versions of SQLite might 2598** panic rather than return SQLITE_MISUSE. 2599** 2600** See also: [sqlite3_bind_parameter_count()], 2601** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 2602** 2603** Requirements: 2604** [H13506] [H13509] [H13512] [H13515] [H13518] [H13521] [H13524] [H13527] 2605** [H13530] [H13533] [H13536] [H13539] [H13542] [H13545] [H13548] [H13551] 2606** 2607*/ 2608int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 2609int sqlite3_bind_double(sqlite3_stmt*, int, double); 2610int sqlite3_bind_int(sqlite3_stmt*, int, int); 2611int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 2612int sqlite3_bind_null(sqlite3_stmt*, int); 2613int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 2614int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 2615int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 2616int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 2617 2618/* 2619** CAPI3REF: Number Of SQL Parameters {H13600} <S70300> 2620** 2621** This routine can be used to find the number of [SQL parameters] 2622** in a [prepared statement]. SQL parameters are tokens of the 2623** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 2624** placeholders for values that are [sqlite3_bind_blob | bound] 2625** to the parameters at a later time. 2626** 2627** This routine actually returns the index of the largest (rightmost) 2628** parameter. For all forms except ?NNN, this will correspond to the 2629** number of unique parameters. If parameters of the ?NNN are used, 2630** there may be gaps in the list. 2631** 2632** See also: [sqlite3_bind_blob|sqlite3_bind()], 2633** [sqlite3_bind_parameter_name()], and 2634** [sqlite3_bind_parameter_index()]. 2635** 2636** Requirements: 2637** [H13601] 2638*/ 2639int sqlite3_bind_parameter_count(sqlite3_stmt*); 2640 2641/* 2642** CAPI3REF: Name Of A Host Parameter {H13620} <S70300> 2643** 2644** This routine returns a pointer to the name of the n-th 2645** [SQL parameter] in a [prepared statement]. 2646** SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 2647** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 2648** respectively. 2649** In other words, the initial ":" or "$" or "@" or "?" 2650** is included as part of the name. 2651** Parameters of the form "?" without a following integer have no name 2652** and are also referred to as "anonymous parameters". 2653** 2654** The first host parameter has an index of 1, not 0. 2655** 2656** If the value n is out of range or if the n-th parameter is 2657** nameless, then NULL is returned. The returned string is 2658** always in UTF-8 encoding even if the named parameter was 2659** originally specified as UTF-16 in [sqlite3_prepare16()] or 2660** [sqlite3_prepare16_v2()]. 2661** 2662** See also: [sqlite3_bind_blob|sqlite3_bind()], 2663** [sqlite3_bind_parameter_count()], and 2664** [sqlite3_bind_parameter_index()]. 2665** 2666** Requirements: 2667** [H13621] 2668*/ 2669const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 2670 2671/* 2672** CAPI3REF: Index Of A Parameter With A Given Name {H13640} <S70300> 2673** 2674** Return the index of an SQL parameter given its name. The 2675** index value returned is suitable for use as the second 2676** parameter to [sqlite3_bind_blob|sqlite3_bind()]. A zero 2677** is returned if no matching parameter is found. The parameter 2678** name must be given in UTF-8 even if the original statement 2679** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 2680** 2681** See also: [sqlite3_bind_blob|sqlite3_bind()], 2682** [sqlite3_bind_parameter_count()], and 2683** [sqlite3_bind_parameter_index()]. 2684** 2685** Requirements: 2686** [H13641] 2687*/ 2688int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 2689 2690/* 2691** CAPI3REF: Reset All Bindings On A Prepared Statement {H13660} <S70300> 2692** 2693** Contrary to the intuition of many, [sqlite3_reset()] does not reset 2694** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 2695** Use this routine to reset all host parameters to NULL. 2696** 2697** Requirements: 2698** [H13661] 2699*/ 2700int sqlite3_clear_bindings(sqlite3_stmt*); 2701 2702/* 2703** CAPI3REF: Number Of Columns In A Result Set {H13710} <S10700> 2704** 2705** Return the number of columns in the result set returned by the 2706** [prepared statement]. This routine returns 0 if pStmt is an SQL 2707** statement that does not return data (for example an [UPDATE]). 2708** 2709** Requirements: 2710** [H13711] 2711*/ 2712int sqlite3_column_count(sqlite3_stmt *pStmt); 2713 2714/* 2715** CAPI3REF: Column Names In A Result Set {H13720} <S10700> 2716** 2717** These routines return the name assigned to a particular column 2718** in the result set of a [SELECT] statement. The sqlite3_column_name() 2719** interface returns a pointer to a zero-terminated UTF-8 string 2720** and sqlite3_column_name16() returns a pointer to a zero-terminated 2721** UTF-16 string. The first parameter is the [prepared statement] 2722** that implements the [SELECT] statement. The second parameter is the 2723** column number. The leftmost column is number 0. 2724** 2725** The returned string pointer is valid until either the [prepared statement] 2726** is destroyed by [sqlite3_finalize()] or until the next call to 2727** sqlite3_column_name() or sqlite3_column_name16() on the same column. 2728** 2729** If sqlite3_malloc() fails during the processing of either routine 2730** (for example during a conversion from UTF-8 to UTF-16) then a 2731** NULL pointer is returned. 2732** 2733** The name of a result column is the value of the "AS" clause for 2734** that column, if there is an AS clause. If there is no AS clause 2735** then the name of the column is unspecified and may change from 2736** one release of SQLite to the next. 2737** 2738** Requirements: 2739** [H13721] [H13723] [H13724] [H13725] [H13726] [H13727] 2740*/ 2741const char *sqlite3_column_name(sqlite3_stmt*, int N); 2742const void *sqlite3_column_name16(sqlite3_stmt*, int N); 2743 2744/* 2745** CAPI3REF: Source Of Data In A Query Result {H13740} <S10700> 2746** 2747** These routines provide a means to determine what column of what 2748** table in which database a result of a [SELECT] statement comes from. 2749** The name of the database or table or column can be returned as 2750** either a UTF-8 or UTF-16 string. The _database_ routines return 2751** the database name, the _table_ routines return the table name, and 2752** the origin_ routines return the column name. 2753** The returned string is valid until the [prepared statement] is destroyed 2754** using [sqlite3_finalize()] or until the same information is requested 2755** again in a different encoding. 2756** 2757** The names returned are the original un-aliased names of the 2758** database, table, and column. 2759** 2760** The first argument to the following calls is a [prepared statement]. 2761** These functions return information about the Nth column returned by 2762** the statement, where N is the second function argument. 2763** 2764** If the Nth column returned by the statement is an expression or 2765** subquery and is not a column value, then all of these functions return 2766** NULL. These routine might also return NULL if a memory allocation error 2767** occurs. Otherwise, they return the name of the attached database, table 2768** and column that query result column was extracted from. 2769** 2770** As with all other SQLite APIs, those postfixed with "16" return 2771** UTF-16 encoded strings, the other functions return UTF-8. {END} 2772** 2773** These APIs are only available if the library was compiled with the 2774** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 2775** 2776** {A13751} 2777** If two or more threads call one or more of these routines against the same 2778** prepared statement and column at the same time then the results are 2779** undefined. 2780** 2781** Requirements: 2782** [H13741] [H13742] [H13743] [H13744] [H13745] [H13746] [H13748] 2783** 2784** If two or more threads call one or more 2785** [sqlite3_column_database_name | column metadata interfaces] 2786** for the same [prepared statement] and result column 2787** at the same time then the results are undefined. 2788*/ 2789const char *sqlite3_column_database_name(sqlite3_stmt*,int); 2790const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 2791const char *sqlite3_column_table_name(sqlite3_stmt*,int); 2792const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 2793const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 2794const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 2795 2796/* 2797** CAPI3REF: Declared Datatype Of A Query Result {H13760} <S10700> 2798** 2799** The first parameter is a [prepared statement]. 2800** If this statement is a [SELECT] statement and the Nth column of the 2801** returned result set of that [SELECT] is a table column (not an 2802** expression or subquery) then the declared type of the table 2803** column is returned. If the Nth column of the result set is an 2804** expression or subquery, then a NULL pointer is returned. 2805** The returned string is always UTF-8 encoded. {END} 2806** 2807** For example, given the database schema: 2808** 2809** CREATE TABLE t1(c1 VARIANT); 2810** 2811** and the following statement to be compiled: 2812** 2813** SELECT c1 + 1, c1 FROM t1; 2814** 2815** this routine would return the string "VARIANT" for the second result 2816** column (i==1), and a NULL pointer for the first result column (i==0). 2817** 2818** SQLite uses dynamic run-time typing. So just because a column 2819** is declared to contain a particular type does not mean that the 2820** data stored in that column is of the declared type. SQLite is 2821** strongly typed, but the typing is dynamic not static. Type 2822** is associated with individual values, not with the containers 2823** used to hold those values. 2824** 2825** Requirements: 2826** [H13761] [H13762] [H13763] 2827*/ 2828const char *sqlite3_column_decltype(sqlite3_stmt*,int); 2829const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 2830 2831/* 2832** CAPI3REF: Evaluate An SQL Statement {H13200} <S10000> 2833** 2834** After a [prepared statement] has been prepared using either 2835** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 2836** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 2837** must be called one or more times to evaluate the statement. 2838** 2839** The details of the behavior of the sqlite3_step() interface depend 2840** on whether the statement was prepared using the newer "v2" interface 2841** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 2842** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 2843** new "v2" interface is recommended for new applications but the legacy 2844** interface will continue to be supported. 2845** 2846** In the legacy interface, the return value will be either [SQLITE_BUSY], 2847** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 2848** With the "v2" interface, any of the other [result codes] or 2849** [extended result codes] might be returned as well. 2850** 2851** [SQLITE_BUSY] means that the database engine was unable to acquire the 2852** database locks it needs to do its job. If the statement is a [COMMIT] 2853** or occurs outside of an explicit transaction, then you can retry the 2854** statement. If the statement is not a [COMMIT] and occurs within a 2855** explicit transaction then you should rollback the transaction before 2856** continuing. 2857** 2858** [SQLITE_DONE] means that the statement has finished executing 2859** successfully. sqlite3_step() should not be called again on this virtual 2860** machine without first calling [sqlite3_reset()] to reset the virtual 2861** machine back to its initial state. 2862** 2863** If the SQL statement being executed returns any data, then [SQLITE_ROW] 2864** is returned each time a new row of data is ready for processing by the 2865** caller. The values may be accessed using the [column access functions]. 2866** sqlite3_step() is called again to retrieve the next row of data. 2867** 2868** [SQLITE_ERROR] means that a run-time error (such as a constraint 2869** violation) has occurred. sqlite3_step() should not be called again on 2870** the VM. More information may be found by calling [sqlite3_errmsg()]. 2871** With the legacy interface, a more specific error code (for example, 2872** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 2873** can be obtained by calling [sqlite3_reset()] on the 2874** [prepared statement]. In the "v2" interface, 2875** the more specific error code is returned directly by sqlite3_step(). 2876** 2877** [SQLITE_MISUSE] means that the this routine was called inappropriately. 2878** Perhaps it was called on a [prepared statement] that has 2879** already been [sqlite3_finalize | finalized] or on one that had 2880** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 2881** be the case that the same database connection is being used by two or 2882** more threads at the same moment in time. 2883** 2884** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 2885** API always returns a generic error code, [SQLITE_ERROR], following any 2886** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 2887** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 2888** specific [error codes] that better describes the error. 2889** We admit that this is a goofy design. The problem has been fixed 2890** with the "v2" interface. If you prepare all of your SQL statements 2891** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 2892** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 2893** then the more specific [error codes] are returned directly 2894** by sqlite3_step(). The use of the "v2" interface is recommended. 2895** 2896** Requirements: 2897** [H13202] [H15304] [H15306] [H15308] [H15310] 2898*/ 2899int sqlite3_step(sqlite3_stmt*); 2900 2901/* 2902** CAPI3REF: Number of columns in a result set {H13770} <S10700> 2903** 2904** Returns the number of values in the current row of the result set. 2905** 2906** Requirements: 2907** [H13771] [H13772] 2908*/ 2909int sqlite3_data_count(sqlite3_stmt *pStmt); 2910 2911/* 2912** CAPI3REF: Fundamental Datatypes {H10265} <S10110><S10120> 2913** KEYWORDS: SQLITE_TEXT 2914** 2915** {H10266} Every value in SQLite has one of five fundamental datatypes: 2916** 2917** <ul> 2918** <li> 64-bit signed integer 2919** <li> 64-bit IEEE floating point number 2920** <li> string 2921** <li> BLOB 2922** <li> NULL 2923** </ul> {END} 2924** 2925** These constants are codes for each of those types. 2926** 2927** Note that the SQLITE_TEXT constant was also used in SQLite version 2 2928** for a completely different meaning. Software that links against both 2929** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 2930** SQLITE_TEXT. 2931*/ 2932#define SQLITE_INTEGER 1 2933#define SQLITE_FLOAT 2 2934#define SQLITE_BLOB 4 2935#define SQLITE_NULL 5 2936#ifdef SQLITE_TEXT 2937# undef SQLITE_TEXT 2938#else 2939# define SQLITE_TEXT 3 2940#endif 2941#define SQLITE3_TEXT 3 2942 2943/* 2944** CAPI3REF: Result Values From A Query {H13800} <S10700> 2945** KEYWORDS: {column access functions} 2946** 2947** These routines form the "result set query" interface. 2948** 2949** These routines return information about a single column of the current 2950** result row of a query. In every case the first argument is a pointer 2951** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 2952** that was returned from [sqlite3_prepare_v2()] or one of its variants) 2953** and the second argument is the index of the column for which information 2954** should be returned. The leftmost column of the result set has the index 0. 2955** The number of columns in the result can be determined using 2956** [sqlite3_column_count()]. 2957** 2958** If the SQL statement does not currently point to a valid row, or if the 2959** column index is out of range, the result is undefined. 2960** These routines may only be called when the most recent call to 2961** [sqlite3_step()] has returned [SQLITE_ROW] and neither 2962** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 2963** If any of these routines are called after [sqlite3_reset()] or 2964** [sqlite3_finalize()] or after [sqlite3_step()] has returned 2965** something other than [SQLITE_ROW], the results are undefined. 2966** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 2967** are called from a different thread while any of these routines 2968** are pending, then the results are undefined. 2969** 2970** The sqlite3_column_type() routine returns the 2971** [SQLITE_INTEGER | datatype code] for the initial data type 2972** of the result column. The returned value is one of [SQLITE_INTEGER], 2973** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 2974** returned by sqlite3_column_type() is only meaningful if no type 2975** conversions have occurred as described below. After a type conversion, 2976** the value returned by sqlite3_column_type() is undefined. Future 2977** versions of SQLite may change the behavior of sqlite3_column_type() 2978** following a type conversion. 2979** 2980** If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 2981** routine returns the number of bytes in that BLOB or string. 2982** If the result is a UTF-16 string, then sqlite3_column_bytes() converts 2983** the string to UTF-8 and then returns the number of bytes. 2984** If the result is a numeric value then sqlite3_column_bytes() uses 2985** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 2986** the number of bytes in that string. 2987** The value returned does not include the zero terminator at the end 2988** of the string. For clarity: the value returned is the number of 2989** bytes in the string, not the number of characters. 2990** 2991** Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 2992** even empty strings, are always zero terminated. The return 2993** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary 2994** pointer, possibly even a NULL pointer. 2995** 2996** The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes() 2997** but leaves the result in UTF-16 in native byte order instead of UTF-8. 2998** The zero terminator is not included in this count. 2999** 3000** The object returned by [sqlite3_column_value()] is an 3001** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3002** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3003** If the [unprotected sqlite3_value] object returned by 3004** [sqlite3_column_value()] is used in any other way, including calls 3005** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3006** or [sqlite3_value_bytes()], then the behavior is undefined. 3007** 3008** These routines attempt to convert the value where appropriate. For 3009** example, if the internal representation is FLOAT and a text result 3010** is requested, [sqlite3_snprintf()] is used internally to perform the 3011** conversion automatically. The following table details the conversions 3012** that are applied: 3013** 3014** <blockquote> 3015** <table border="1"> 3016** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3017** 3018** <tr><td> NULL <td> INTEGER <td> Result is 0 3019** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3020** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3021** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3022** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3023** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3024** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3025** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3026** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3027** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3028** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3029** <tr><td> TEXT <td> FLOAT <td> Use atof() 3030** <tr><td> TEXT <td> BLOB <td> No change 3031** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3032** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3033** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3034** </table> 3035** </blockquote> 3036** 3037** The table above makes reference to standard C library functions atoi() 3038** and atof(). SQLite does not really use these functions. It has its 3039** own equivalent internal routines. The atoi() and atof() names are 3040** used in the table for brevity and because they are familiar to most 3041** C programmers. 3042** 3043** Note that when type conversions occur, pointers returned by prior 3044** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3045** sqlite3_column_text16() may be invalidated. 3046** Type conversions and pointer invalidations might occur 3047** in the following cases: 3048** 3049** <ul> 3050** <li> The initial content is a BLOB and sqlite3_column_text() or 3051** sqlite3_column_text16() is called. A zero-terminator might 3052** need to be added to the string.</li> 3053** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3054** sqlite3_column_text16() is called. The content must be converted 3055** to UTF-16.</li> 3056** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3057** sqlite3_column_text() is called. The content must be converted 3058** to UTF-8.</li> 3059** </ul> 3060** 3061** Conversions between UTF-16be and UTF-16le are always done in place and do 3062** not invalidate a prior pointer, though of course the content of the buffer 3063** that the prior pointer points to will have been modified. Other kinds 3064** of conversion are done in place when it is possible, but sometimes they 3065** are not possible and in those cases prior pointers are invalidated. 3066** 3067** The safest and easiest to remember policy is to invoke these routines 3068** in one of the following ways: 3069** 3070** <ul> 3071** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3072** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3073** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3074** </ul> 3075** 3076** In other words, you should call sqlite3_column_text(), 3077** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3078** into the desired format, then invoke sqlite3_column_bytes() or 3079** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3080** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3081** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3082** with calls to sqlite3_column_bytes(). 3083** 3084** The pointers returned are valid until a type conversion occurs as 3085** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3086** [sqlite3_finalize()] is called. The memory space used to hold strings 3087** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3088** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3089** [sqlite3_free()]. 3090** 3091** If a memory allocation error occurs during the evaluation of any 3092** of these routines, a default value is returned. The default value 3093** is either the integer 0, the floating point number 0.0, or a NULL 3094** pointer. Subsequent calls to [sqlite3_errcode()] will return 3095** [SQLITE_NOMEM]. 3096** 3097** Requirements: 3098** [H13803] [H13806] [H13809] [H13812] [H13815] [H13818] [H13821] [H13824] 3099** [H13827] [H13830] 3100*/ 3101const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3102int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3103int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3104double sqlite3_column_double(sqlite3_stmt*, int iCol); 3105int sqlite3_column_int(sqlite3_stmt*, int iCol); 3106sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3107const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3108const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3109int sqlite3_column_type(sqlite3_stmt*, int iCol); 3110sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3111 3112/* 3113** CAPI3REF: Destroy A Prepared Statement Object {H13300} <S70300><S30100> 3114** 3115** The sqlite3_finalize() function is called to delete a [prepared statement]. 3116** If the statement was executed successfully or not executed at all, then 3117** SQLITE_OK is returned. If execution of the statement failed then an 3118** [error code] or [extended error code] is returned. 3119** 3120** This routine can be called at any point during the execution of the 3121** [prepared statement]. If the virtual machine has not 3122** completed execution when this routine is called, that is like 3123** encountering an error or an [sqlite3_interrupt | interrupt]. 3124** Incomplete updates may be rolled back and transactions canceled, 3125** depending on the circumstances, and the 3126** [error code] returned will be [SQLITE_ABORT]. 3127** 3128** Requirements: 3129** [H11302] [H11304] 3130*/ 3131int sqlite3_finalize(sqlite3_stmt *pStmt); 3132 3133/* 3134** CAPI3REF: Reset A Prepared Statement Object {H13330} <S70300> 3135** 3136** The sqlite3_reset() function is called to reset a [prepared statement] 3137** object back to its initial state, ready to be re-executed. 3138** Any SQL statement variables that had values bound to them using 3139** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3140** Use [sqlite3_clear_bindings()] to reset the bindings. 3141** 3142** {H11332} The [sqlite3_reset(S)] interface resets the [prepared statement] S 3143** back to the beginning of its program. 3144** 3145** {H11334} If the most recent call to [sqlite3_step(S)] for the 3146** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3147** or if [sqlite3_step(S)] has never before been called on S, 3148** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3149** 3150** {H11336} If the most recent call to [sqlite3_step(S)] for the 3151** [prepared statement] S indicated an error, then 3152** [sqlite3_reset(S)] returns an appropriate [error code]. 3153** 3154** {H11338} The [sqlite3_reset(S)] interface does not change the values 3155** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3156*/ 3157int sqlite3_reset(sqlite3_stmt *pStmt); 3158 3159/* 3160** CAPI3REF: Create Or Redefine SQL Functions {H16100} <S20200> 3161** KEYWORDS: {function creation routines} 3162** KEYWORDS: {application-defined SQL function} 3163** KEYWORDS: {application-defined SQL functions} 3164** 3165** These two functions (collectively known as "function creation routines") 3166** are used to add SQL functions or aggregates or to redefine the behavior 3167** of existing SQL functions or aggregates. The only difference between the 3168** two is that the second parameter, the name of the (scalar) function or 3169** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16 3170** for sqlite3_create_function16(). 3171** 3172** The first parameter is the [database connection] to which the SQL 3173** function is to be added. If a single program uses more than one database 3174** connection internally, then SQL functions must be added individually to 3175** each database connection. 3176** 3177** The second parameter is the name of the SQL function to be created or 3178** redefined. The length of the name is limited to 255 bytes, exclusive of 3179** the zero-terminator. Note that the name length limit is in bytes, not 3180** characters. Any attempt to create a function with a longer name 3181** will result in [SQLITE_ERROR] being returned. 3182** 3183** The third parameter (nArg) 3184** is the number of arguments that the SQL function or 3185** aggregate takes. If this parameter is -1, then the SQL function or 3186** aggregate may take any number of arguments between 0 and the limit 3187** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3188** parameter is less than -1 or greater than 127 then the behavior is 3189** undefined. 3190** 3191** The fourth parameter, eTextRep, specifies what 3192** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3193** its parameters. Any SQL function implementation should be able to work 3194** work with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3195** more efficient with one encoding than another. An application may 3196** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3197** times with the same function but with different values of eTextRep. 3198** When multiple implementations of the same function are available, SQLite 3199** will pick the one that involves the least amount of data conversion. 3200** If there is only a single implementation which does not care what text 3201** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3202** 3203** The fifth parameter is an arbitrary pointer. The implementation of the 3204** function can gain access to this pointer using [sqlite3_user_data()]. 3205** 3206** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are 3207** pointers to C-language functions that implement the SQL function or 3208** aggregate. A scalar SQL function requires an implementation of the xFunc 3209** callback only, NULL pointers should be passed as the xStep and xFinal 3210** parameters. An aggregate SQL function requires an implementation of xStep 3211** and xFinal and NULL should be passed for xFunc. To delete an existing 3212** SQL function or aggregate, pass NULL for all three function callbacks. 3213** 3214** It is permitted to register multiple implementations of the same 3215** functions with the same name but with either differing numbers of 3216** arguments or differing preferred text encodings. SQLite will use 3217** the implementation that most closely matches the way in which the 3218** SQL function is used. A function implementation with a non-negative 3219** nArg parameter is a better match than a function implementation with 3220** a negative nArg. A function where the preferred text encoding 3221** matches the database encoding is a better 3222** match than a function where the encoding is different. 3223** A function where the encoding difference is between UTF16le and UTF16be 3224** is a closer match than a function where the encoding difference is 3225** between UTF8 and UTF16. 3226** 3227** Built-in functions may be overloaded by new application-defined functions. 3228** The first application-defined function with a given name overrides all 3229** built-in functions in the same [database connection] with the same name. 3230** Subsequent application-defined functions of the same name only override 3231** prior application-defined functions that are an exact match for the 3232** number of parameters and preferred encoding. 3233** 3234** An application-defined function is permitted to call other 3235** SQLite interfaces. However, such calls must not 3236** close the database connection nor finalize or reset the prepared 3237** statement in which the function is running. 3238** 3239** Requirements: 3240** [H16103] [H16106] [H16109] [H16112] [H16118] [H16121] [H16127] 3241** [H16130] [H16133] [H16136] [H16139] [H16142] 3242*/ 3243int sqlite3_create_function( 3244 sqlite3 *db, 3245 const char *zFunctionName, 3246 int nArg, 3247 int eTextRep, 3248 void *pApp, 3249 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3250 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3251 void (*xFinal)(sqlite3_context*) 3252); 3253int sqlite3_create_function16( 3254 sqlite3 *db, 3255 const void *zFunctionName, 3256 int nArg, 3257 int eTextRep, 3258 void *pApp, 3259 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3260 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3261 void (*xFinal)(sqlite3_context*) 3262); 3263 3264/* 3265** CAPI3REF: Text Encodings {H10267} <S50200> <H16100> 3266** 3267** These constant define integer codes that represent the various 3268** text encodings supported by SQLite. 3269*/ 3270#define SQLITE_UTF8 1 3271#define SQLITE_UTF16LE 2 3272#define SQLITE_UTF16BE 3 3273#define SQLITE_UTF16 4 /* Use native byte order */ 3274#define SQLITE_ANY 5 /* sqlite3_create_function only */ 3275#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3276 3277/* 3278** CAPI3REF: Deprecated Functions 3279** DEPRECATED 3280** 3281** These functions are [deprecated]. In order to maintain 3282** backwards compatibility with older code, these functions continue 3283** to be supported. However, new applications should avoid 3284** the use of these functions. To help encourage people to avoid 3285** using these functions, we are not going to tell you what they do. 3286*/ 3287#ifndef SQLITE_OMIT_DEPRECATED 3288SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3289SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3290SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3291SQLITE_DEPRECATED int sqlite3_global_recover(void); 3292SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3293SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3294#endif 3295 3296/* 3297** CAPI3REF: Obtaining SQL Function Parameter Values {H15100} <S20200> 3298** 3299** The C-language implementation of SQL functions and aggregates uses 3300** this set of interface routines to access the parameter values on 3301** the function or aggregate. 3302** 3303** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3304** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3305** define callbacks that implement the SQL functions and aggregates. 3306** The 4th parameter to these callbacks is an array of pointers to 3307** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3308** each parameter to the SQL function. These routines are used to 3309** extract values from the [sqlite3_value] objects. 3310** 3311** These routines work only with [protected sqlite3_value] objects. 3312** Any attempt to use these routines on an [unprotected sqlite3_value] 3313** object results in undefined behavior. 3314** 3315** These routines work just like the corresponding [column access functions] 3316** except that these routines take a single [protected sqlite3_value] object 3317** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3318** 3319** The sqlite3_value_text16() interface extracts a UTF-16 string 3320** in the native byte-order of the host machine. The 3321** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3322** extract UTF-16 strings as big-endian and little-endian respectively. 3323** 3324** The sqlite3_value_numeric_type() interface attempts to apply 3325** numeric affinity to the value. This means that an attempt is 3326** made to convert the value to an integer or floating point. If 3327** such a conversion is possible without loss of information (in other 3328** words, if the value is a string that looks like a number) 3329** then the conversion is performed. Otherwise no conversion occurs. 3330** The [SQLITE_INTEGER | datatype] after conversion is returned. 3331** 3332** Please pay particular attention to the fact that the pointer returned 3333** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3334** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3335** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3336** or [sqlite3_value_text16()]. 3337** 3338** These routines must be called from the same thread as 3339** the SQL function that supplied the [sqlite3_value*] parameters. 3340** 3341** Requirements: 3342** [H15103] [H15106] [H15109] [H15112] [H15115] [H15118] [H15121] [H15124] 3343** [H15127] [H15130] [H15133] [H15136] 3344*/ 3345const void *sqlite3_value_blob(sqlite3_value*); 3346int sqlite3_value_bytes(sqlite3_value*); 3347int sqlite3_value_bytes16(sqlite3_value*); 3348double sqlite3_value_double(sqlite3_value*); 3349int sqlite3_value_int(sqlite3_value*); 3350sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3351const unsigned char *sqlite3_value_text(sqlite3_value*); 3352const void *sqlite3_value_text16(sqlite3_value*); 3353const void *sqlite3_value_text16le(sqlite3_value*); 3354const void *sqlite3_value_text16be(sqlite3_value*); 3355int sqlite3_value_type(sqlite3_value*); 3356int sqlite3_value_numeric_type(sqlite3_value*); 3357 3358/* 3359** CAPI3REF: Obtain Aggregate Function Context {H16210} <S20200> 3360** 3361** The implementation of aggregate SQL functions use this routine to allocate 3362** a structure for storing their state. 3363** 3364** The first time the sqlite3_aggregate_context() routine is called for a 3365** particular aggregate, SQLite allocates nBytes of memory, zeroes out that 3366** memory, and returns a pointer to it. On second and subsequent calls to 3367** sqlite3_aggregate_context() for the same aggregate function index, 3368** the same buffer is returned. The implementation of the aggregate can use 3369** the returned buffer to accumulate data. 3370** 3371** SQLite automatically frees the allocated buffer when the aggregate 3372** query concludes. 3373** 3374** The first parameter should be a copy of the 3375** [sqlite3_context | SQL function context] that is the first parameter 3376** to the callback routine that implements the aggregate function. 3377** 3378** This routine must be called from the same thread in which 3379** the aggregate SQL function is running. 3380** 3381** Requirements: 3382** [H16211] [H16213] [H16215] [H16217] 3383*/ 3384void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 3385 3386/* 3387** CAPI3REF: User Data For Functions {H16240} <S20200> 3388** 3389** The sqlite3_user_data() interface returns a copy of 3390** the pointer that was the pUserData parameter (the 5th parameter) 3391** of the [sqlite3_create_function()] 3392** and [sqlite3_create_function16()] routines that originally 3393** registered the application defined function. {END} 3394** 3395** This routine must be called from the same thread in which 3396** the application-defined function is running. 3397** 3398** Requirements: 3399** [H16243] 3400*/ 3401void *sqlite3_user_data(sqlite3_context*); 3402 3403/* 3404** CAPI3REF: Database Connection For Functions {H16250} <S60600><S20200> 3405** 3406** The sqlite3_context_db_handle() interface returns a copy of 3407** the pointer to the [database connection] (the 1st parameter) 3408** of the [sqlite3_create_function()] 3409** and [sqlite3_create_function16()] routines that originally 3410** registered the application defined function. 3411** 3412** Requirements: 3413** [H16253] 3414*/ 3415sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 3416 3417/* 3418** CAPI3REF: Function Auxiliary Data {H16270} <S20200> 3419** 3420** The following two functions may be used by scalar SQL functions to 3421** associate metadata with argument values. If the same value is passed to 3422** multiple invocations of the same SQL function during query execution, under 3423** some circumstances the associated metadata may be preserved. This may 3424** be used, for example, to add a regular-expression matching scalar 3425** function. The compiled version of the regular expression is stored as 3426** metadata associated with the SQL value passed as the regular expression 3427** pattern. The compiled regular expression can be reused on multiple 3428** invocations of the same function so that the original pattern string 3429** does not need to be recompiled on each invocation. 3430** 3431** The sqlite3_get_auxdata() interface returns a pointer to the metadata 3432** associated by the sqlite3_set_auxdata() function with the Nth argument 3433** value to the application-defined function. If no metadata has been ever 3434** been set for the Nth argument of the function, or if the corresponding 3435** function parameter has changed since the meta-data was set, 3436** then sqlite3_get_auxdata() returns a NULL pointer. 3437** 3438** The sqlite3_set_auxdata() interface saves the metadata 3439** pointed to by its 3rd parameter as the metadata for the N-th 3440** argument of the application-defined function. Subsequent 3441** calls to sqlite3_get_auxdata() might return this data, if it has 3442** not been destroyed. 3443** If it is not NULL, SQLite will invoke the destructor 3444** function given by the 4th parameter to sqlite3_set_auxdata() on 3445** the metadata when the corresponding function parameter changes 3446** or when the SQL statement completes, whichever comes first. 3447** 3448** SQLite is free to call the destructor and drop metadata on any 3449** parameter of any function at any time. The only guarantee is that 3450** the destructor will be called before the metadata is dropped. 3451** 3452** In practice, metadata is preserved between function calls for 3453** expressions that are constant at compile time. This includes literal 3454** values and SQL variables. 3455** 3456** These routines must be called from the same thread in which 3457** the SQL function is running. 3458** 3459** Requirements: 3460** [H16272] [H16274] [H16276] [H16277] [H16278] [H16279] 3461*/ 3462void *sqlite3_get_auxdata(sqlite3_context*, int N); 3463void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 3464 3465 3466/* 3467** CAPI3REF: Constants Defining Special Destructor Behavior {H10280} <S30100> 3468** 3469** These are special values for the destructor that is passed in as the 3470** final argument to routines like [sqlite3_result_blob()]. If the destructor 3471** argument is SQLITE_STATIC, it means that the content pointer is constant 3472** and will never change. It does not need to be destroyed. The 3473** SQLITE_TRANSIENT value means that the content will likely change in 3474** the near future and that SQLite should make its own private copy of 3475** the content before returning. 3476** 3477** The typedef is necessary to work around problems in certain 3478** C++ compilers. See ticket #2191. 3479*/ 3480typedef void (*sqlite3_destructor_type)(void*); 3481#define SQLITE_STATIC ((sqlite3_destructor_type)0) 3482#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 3483 3484/* 3485** CAPI3REF: Setting The Result Of An SQL Function {H16400} <S20200> 3486** 3487** These routines are used by the xFunc or xFinal callbacks that 3488** implement SQL functions and aggregates. See 3489** [sqlite3_create_function()] and [sqlite3_create_function16()] 3490** for additional information. 3491** 3492** These functions work very much like the [parameter binding] family of 3493** functions used to bind values to host parameters in prepared statements. 3494** Refer to the [SQL parameter] documentation for additional information. 3495** 3496** The sqlite3_result_blob() interface sets the result from 3497** an application-defined function to be the BLOB whose content is pointed 3498** to by the second parameter and which is N bytes long where N is the 3499** third parameter. 3500** 3501** The sqlite3_result_zeroblob() interfaces set the result of 3502** the application-defined function to be a BLOB containing all zero 3503** bytes and N bytes in size, where N is the value of the 2nd parameter. 3504** 3505** The sqlite3_result_double() interface sets the result from 3506** an application-defined function to be a floating point value specified 3507** by its 2nd argument. 3508** 3509** The sqlite3_result_error() and sqlite3_result_error16() functions 3510** cause the implemented SQL function to throw an exception. 3511** SQLite uses the string pointed to by the 3512** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 3513** as the text of an error message. SQLite interprets the error 3514** message string from sqlite3_result_error() as UTF-8. SQLite 3515** interprets the string from sqlite3_result_error16() as UTF-16 in native 3516** byte order. If the third parameter to sqlite3_result_error() 3517** or sqlite3_result_error16() is negative then SQLite takes as the error 3518** message all text up through the first zero character. 3519** If the third parameter to sqlite3_result_error() or 3520** sqlite3_result_error16() is non-negative then SQLite takes that many 3521** bytes (not characters) from the 2nd parameter as the error message. 3522** The sqlite3_result_error() and sqlite3_result_error16() 3523** routines make a private copy of the error message text before 3524** they return. Hence, the calling function can deallocate or 3525** modify the text after they return without harm. 3526** The sqlite3_result_error_code() function changes the error code 3527** returned by SQLite as a result of an error in a function. By default, 3528** the error code is SQLITE_ERROR. A subsequent call to sqlite3_result_error() 3529** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 3530** 3531** The sqlite3_result_toobig() interface causes SQLite to throw an error 3532** indicating that a string or BLOB is to long to represent. 3533** 3534** The sqlite3_result_nomem() interface causes SQLite to throw an error 3535** indicating that a memory allocation failed. 3536** 3537** The sqlite3_result_int() interface sets the return value 3538** of the application-defined function to be the 32-bit signed integer 3539** value given in the 2nd argument. 3540** The sqlite3_result_int64() interface sets the return value 3541** of the application-defined function to be the 64-bit signed integer 3542** value given in the 2nd argument. 3543** 3544** The sqlite3_result_null() interface sets the return value 3545** of the application-defined function to be NULL. 3546** 3547** The sqlite3_result_text(), sqlite3_result_text16(), 3548** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 3549** set the return value of the application-defined function to be 3550** a text string which is represented as UTF-8, UTF-16 native byte order, 3551** UTF-16 little endian, or UTF-16 big endian, respectively. 3552** SQLite takes the text result from the application from 3553** the 2nd parameter of the sqlite3_result_text* interfaces. 3554** If the 3rd parameter to the sqlite3_result_text* interfaces 3555** is negative, then SQLite takes result text from the 2nd parameter 3556** through the first zero character. 3557** If the 3rd parameter to the sqlite3_result_text* interfaces 3558** is non-negative, then as many bytes (not characters) of the text 3559** pointed to by the 2nd parameter are taken as the application-defined 3560** function result. 3561** If the 4th parameter to the sqlite3_result_text* interfaces 3562** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 3563** function as the destructor on the text or BLOB result when it has 3564** finished using that result. 3565** If the 4th parameter to the sqlite3_result_text* interfaces or to 3566** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 3567** assumes that the text or BLOB result is in constant space and does not 3568** copy the content of the parameter nor call a destructor on the content 3569** when it has finished using that result. 3570** If the 4th parameter to the sqlite3_result_text* interfaces 3571** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 3572** then SQLite makes a copy of the result into space obtained from 3573** from [sqlite3_malloc()] before it returns. 3574** 3575** The sqlite3_result_value() interface sets the result of 3576** the application-defined function to be a copy the 3577** [unprotected sqlite3_value] object specified by the 2nd parameter. The 3578** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 3579** so that the [sqlite3_value] specified in the parameter may change or 3580** be deallocated after sqlite3_result_value() returns without harm. 3581** A [protected sqlite3_value] object may always be used where an 3582** [unprotected sqlite3_value] object is required, so either 3583** kind of [sqlite3_value] object can be used with this interface. 3584** 3585** If these routines are called from within the different thread 3586** than the one containing the application-defined function that received 3587** the [sqlite3_context] pointer, the results are undefined. 3588** 3589** Requirements: 3590** [H16403] [H16406] [H16409] [H16412] [H16415] [H16418] [H16421] [H16424] 3591** [H16427] [H16430] [H16433] [H16436] [H16439] [H16442] [H16445] [H16448] 3592** [H16451] [H16454] [H16457] [H16460] [H16463] 3593*/ 3594void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 3595void sqlite3_result_double(sqlite3_context*, double); 3596void sqlite3_result_error(sqlite3_context*, const char*, int); 3597void sqlite3_result_error16(sqlite3_context*, const void*, int); 3598void sqlite3_result_error_toobig(sqlite3_context*); 3599void sqlite3_result_error_nomem(sqlite3_context*); 3600void sqlite3_result_error_code(sqlite3_context*, int); 3601void sqlite3_result_int(sqlite3_context*, int); 3602void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 3603void sqlite3_result_null(sqlite3_context*); 3604void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 3605void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 3606void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 3607void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 3608void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 3609void sqlite3_result_zeroblob(sqlite3_context*, int n); 3610 3611/* 3612** CAPI3REF: Define New Collating Sequences {H16600} <S20300> 3613** 3614** These functions are used to add new collation sequences to the 3615** [database connection] specified as the first argument. 3616** 3617** The name of the new collation sequence is specified as a UTF-8 string 3618** for sqlite3_create_collation() and sqlite3_create_collation_v2() 3619** and a UTF-16 string for sqlite3_create_collation16(). In all cases 3620** the name is passed as the second function argument. 3621** 3622** The third argument may be one of the constants [SQLITE_UTF8], 3623** [SQLITE_UTF16LE], or [SQLITE_UTF16BE], indicating that the user-supplied 3624** routine expects to be passed pointers to strings encoded using UTF-8, 3625** UTF-16 little-endian, or UTF-16 big-endian, respectively. The 3626** third argument might also be [SQLITE_UTF16] to indicate that the routine 3627** expects pointers to be UTF-16 strings in the native byte order, or the 3628** argument can be [SQLITE_UTF16_ALIGNED] if the 3629** the routine expects pointers to 16-bit word aligned strings 3630** of UTF-16 in the native byte order. 3631** 3632** A pointer to the user supplied routine must be passed as the fifth 3633** argument. If it is NULL, this is the same as deleting the collation 3634** sequence (so that SQLite cannot call it anymore). 3635** Each time the application supplied function is invoked, it is passed 3636** as its first parameter a copy of the void* passed as the fourth argument 3637** to sqlite3_create_collation() or sqlite3_create_collation16(). 3638** 3639** The remaining arguments to the application-supplied routine are two strings, 3640** each represented by a (length, data) pair and encoded in the encoding 3641** that was passed as the third argument when the collation sequence was 3642** registered. {END} The application defined collation routine should 3643** return negative, zero or positive if the first string is less than, 3644** equal to, or greater than the second string. i.e. (STRING1 - STRING2). 3645** 3646** The sqlite3_create_collation_v2() works like sqlite3_create_collation() 3647** except that it takes an extra argument which is a destructor for 3648** the collation. The destructor is called when the collation is 3649** destroyed and is passed a copy of the fourth parameter void* pointer 3650** of the sqlite3_create_collation_v2(). 3651** Collations are destroyed when they are overridden by later calls to the 3652** collation creation functions or when the [database connection] is closed 3653** using [sqlite3_close()]. 3654** 3655** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 3656** 3657** Requirements: 3658** [H16603] [H16604] [H16606] [H16609] [H16612] [H16615] [H16618] [H16621] 3659** [H16624] [H16627] [H16630] 3660*/ 3661int sqlite3_create_collation( 3662 sqlite3*, 3663 const char *zName, 3664 int eTextRep, 3665 void*, 3666 int(*xCompare)(void*,int,const void*,int,const void*) 3667); 3668int sqlite3_create_collation_v2( 3669 sqlite3*, 3670 const char *zName, 3671 int eTextRep, 3672 void*, 3673 int(*xCompare)(void*,int,const void*,int,const void*), 3674 void(*xDestroy)(void*) 3675); 3676int sqlite3_create_collation16( 3677 sqlite3*, 3678 const void *zName, 3679 int eTextRep, 3680 void*, 3681 int(*xCompare)(void*,int,const void*,int,const void*) 3682); 3683 3684/* 3685** CAPI3REF: Collation Needed Callbacks {H16700} <S20300> 3686** 3687** To avoid having to register all collation sequences before a database 3688** can be used, a single callback function may be registered with the 3689** [database connection] to be called whenever an undefined collation 3690** sequence is required. 3691** 3692** If the function is registered using the sqlite3_collation_needed() API, 3693** then it is passed the names of undefined collation sequences as strings 3694** encoded in UTF-8. {H16703} If sqlite3_collation_needed16() is used, 3695** the names are passed as UTF-16 in machine native byte order. 3696** A call to either function replaces any existing callback. 3697** 3698** When the callback is invoked, the first argument passed is a copy 3699** of the second argument to sqlite3_collation_needed() or 3700** sqlite3_collation_needed16(). The second argument is the database 3701** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 3702** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 3703** sequence function required. The fourth parameter is the name of the 3704** required collation sequence. 3705** 3706** The callback function should register the desired collation using 3707** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 3708** [sqlite3_create_collation_v2()]. 3709** 3710** Requirements: 3711** [H16702] [H16704] [H16706] 3712*/ 3713int sqlite3_collation_needed( 3714 sqlite3*, 3715 void*, 3716 void(*)(void*,sqlite3*,int eTextRep,const char*) 3717); 3718int sqlite3_collation_needed16( 3719 sqlite3*, 3720 void*, 3721 void(*)(void*,sqlite3*,int eTextRep,const void*) 3722); 3723 3724/* 3725** Specify the key for an encrypted database. This routine should be 3726** called right after sqlite3_open(). 3727** 3728** The code to implement this API is not available in the public release 3729** of SQLite. 3730*/ 3731int sqlite3_key( 3732 sqlite3 *db, /* Database to be rekeyed */ 3733 const void *pKey, int nKey /* The key */ 3734); 3735 3736/* 3737** Change the key on an open database. If the current database is not 3738** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 3739** database is decrypted. 3740** 3741** The code to implement this API is not available in the public release 3742** of SQLite. 3743*/ 3744int sqlite3_rekey( 3745 sqlite3 *db, /* Database to be rekeyed */ 3746 const void *pKey, int nKey /* The new key */ 3747); 3748 3749/* 3750** CAPI3REF: Suspend Execution For A Short Time {H10530} <S40410> 3751** 3752** The sqlite3_sleep() function causes the current thread to suspend execution 3753** for at least a number of milliseconds specified in its parameter. 3754** 3755** If the operating system does not support sleep requests with 3756** millisecond time resolution, then the time will be rounded up to 3757** the nearest second. The number of milliseconds of sleep actually 3758** requested from the operating system is returned. 3759** 3760** SQLite implements this interface by calling the xSleep() 3761** method of the default [sqlite3_vfs] object. 3762** 3763** Requirements: [H10533] [H10536] 3764*/ 3765int sqlite3_sleep(int); 3766 3767/* 3768** CAPI3REF: Name Of The Folder Holding Temporary Files {H10310} <S20000> 3769** 3770** If this global variable is made to point to a string which is 3771** the name of a folder (a.k.a. directory), then all temporary files 3772** created by SQLite will be placed in that directory. If this variable 3773** is a NULL pointer, then SQLite performs a search for an appropriate 3774** temporary file directory. 3775** 3776** It is not safe to read or modify this variable in more than one 3777** thread at a time. It is not safe to read or modify this variable 3778** if a [database connection] is being used at the same time in a separate 3779** thread. 3780** It is intended that this variable be set once 3781** as part of process initialization and before any SQLite interface 3782** routines have been called and that this variable remain unchanged 3783** thereafter. 3784** 3785** The [temp_store_directory pragma] may modify this variable and cause 3786** it to point to memory obtained from [sqlite3_malloc]. Furthermore, 3787** the [temp_store_directory pragma] always assumes that any string 3788** that this variable points to is held in memory obtained from 3789** [sqlite3_malloc] and the pragma may attempt to free that memory 3790** using [sqlite3_free]. 3791** Hence, if this variable is modified directly, either it should be 3792** made NULL or made to point to memory obtained from [sqlite3_malloc] 3793** or else the use of the [temp_store_directory pragma] should be avoided. 3794*/ 3795SQLITE_EXTERN char *sqlite3_temp_directory; 3796 3797/* 3798** CAPI3REF: Test For Auto-Commit Mode {H12930} <S60200> 3799** KEYWORDS: {autocommit mode} 3800** 3801** The sqlite3_get_autocommit() interface returns non-zero or 3802** zero if the given database connection is or is not in autocommit mode, 3803** respectively. Autocommit mode is on by default. 3804** Autocommit mode is disabled by a [BEGIN] statement. 3805** Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 3806** 3807** If certain kinds of errors occur on a statement within a multi-statement 3808** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 3809** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 3810** transaction might be rolled back automatically. The only way to 3811** find out whether SQLite automatically rolled back the transaction after 3812** an error is to use this function. 3813** 3814** If another thread changes the autocommit status of the database 3815** connection while this routine is running, then the return value 3816** is undefined. 3817** 3818** Requirements: [H12931] [H12932] [H12933] [H12934] 3819*/ 3820int sqlite3_get_autocommit(sqlite3*); 3821 3822/* 3823** CAPI3REF: Find The Database Handle Of A Prepared Statement {H13120} <S60600> 3824** 3825** The sqlite3_db_handle interface returns the [database connection] handle 3826** to which a [prepared statement] belongs. The [database connection] 3827** returned by sqlite3_db_handle is the same [database connection] that was the first argument 3828** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 3829** create the statement in the first place. 3830** 3831** Requirements: [H13123] 3832*/ 3833sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 3834 3835/* 3836** CAPI3REF: Find the next prepared statement {H13140} <S60600> 3837** 3838** This interface returns a pointer to the next [prepared statement] after 3839** pStmt associated with the [database connection] pDb. If pStmt is NULL 3840** then this interface returns a pointer to the first prepared statement 3841** associated with the database connection pDb. If no prepared statement 3842** satisfies the conditions of this routine, it returns NULL. 3843** 3844** The [database connection] pointer D in a call to 3845** [sqlite3_next_stmt(D,S)] must refer to an open database 3846** connection and in particular must not be a NULL pointer. 3847** 3848** Requirements: [H13143] [H13146] [H13149] [H13152] 3849*/ 3850sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 3851 3852/* 3853** CAPI3REF: Commit And Rollback Notification Callbacks {H12950} <S60400> 3854** 3855** The sqlite3_commit_hook() interface registers a callback 3856** function to be invoked whenever a transaction is [COMMIT | committed]. 3857** Any callback set by a previous call to sqlite3_commit_hook() 3858** for the same database connection is overridden. 3859** The sqlite3_rollback_hook() interface registers a callback 3860** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 3861** Any callback set by a previous call to sqlite3_commit_hook() 3862** for the same database connection is overridden. 3863** The pArg argument is passed through to the callback. 3864** If the callback on a commit hook function returns non-zero, 3865** then the commit is converted into a rollback. 3866** 3867** If another function was previously registered, its 3868** pArg value is returned. Otherwise NULL is returned. 3869** 3870** The callback implementation must not do anything that will modify 3871** the database connection that invoked the callback. Any actions 3872** to modify the database connection must be deferred until after the 3873** completion of the [sqlite3_step()] call that triggered the commit 3874** or rollback hook in the first place. 3875** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3876** database connections for the meaning of "modify" in this paragraph. 3877** 3878** Registering a NULL function disables the callback. 3879** 3880** When the commit hook callback routine returns zero, the [COMMIT] 3881** operation is allowed to continue normally. If the commit hook 3882** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 3883** The rollback hook is invoked on a rollback that results from a commit 3884** hook returning non-zero, just as it would be with any other rollback. 3885** 3886** For the purposes of this API, a transaction is said to have been 3887** rolled back if an explicit "ROLLBACK" statement is executed, or 3888** an error or constraint causes an implicit rollback to occur. 3889** The rollback callback is not invoked if a transaction is 3890** automatically rolled back because the database connection is closed. 3891** The rollback callback is not invoked if a transaction is 3892** rolled back because a commit callback returned non-zero. 3893** <todo> Check on this </todo> 3894** 3895** See also the [sqlite3_update_hook()] interface. 3896** 3897** Requirements: 3898** [H12951] [H12952] [H12953] [H12954] [H12955] 3899** [H12961] [H12962] [H12963] [H12964] 3900*/ 3901void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 3902void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 3903 3904/* 3905** CAPI3REF: Data Change Notification Callbacks {H12970} <S60400> 3906** 3907** The sqlite3_update_hook() interface registers a callback function 3908** with the [database connection] identified by the first argument 3909** to be invoked whenever a row is updated, inserted or deleted. 3910** Any callback set by a previous call to this function 3911** for the same database connection is overridden. 3912** 3913** The second argument is a pointer to the function to invoke when a 3914** row is updated, inserted or deleted. 3915** The first argument to the callback is a copy of the third argument 3916** to sqlite3_update_hook(). 3917** The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 3918** or [SQLITE_UPDATE], depending on the operation that caused the callback 3919** to be invoked. 3920** The third and fourth arguments to the callback contain pointers to the 3921** database and table name containing the affected row. 3922** The final callback parameter is the [rowid] of the row. 3923** In the case of an update, this is the [rowid] after the update takes place. 3924** 3925** The update hook is not invoked when internal system tables are 3926** modified (i.e. sqlite_master and sqlite_sequence). 3927** 3928** In the current implementation, the update hook 3929** is not invoked when duplication rows are deleted because of an 3930** [ON CONFLICT | ON CONFLICT REPLACE] clause. Nor is the update hook 3931** invoked when rows are deleted using the [truncate optimization]. 3932** The exceptions defined in this paragraph might change in a future 3933** release of SQLite. 3934** 3935** The update hook implementation must not do anything that will modify 3936** the database connection that invoked the update hook. Any actions 3937** to modify the database connection must be deferred until after the 3938** completion of the [sqlite3_step()] call that triggered the update hook. 3939** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3940** database connections for the meaning of "modify" in this paragraph. 3941** 3942** If another function was previously registered, its pArg value 3943** is returned. Otherwise NULL is returned. 3944** 3945** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 3946** interfaces. 3947** 3948** Requirements: 3949** [H12971] [H12973] [H12975] [H12977] [H12979] [H12981] [H12983] [H12986] 3950*/ 3951void *sqlite3_update_hook( 3952 sqlite3*, 3953 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 3954 void* 3955); 3956 3957/* 3958** CAPI3REF: Enable Or Disable Shared Pager Cache {H10330} <S30900> 3959** KEYWORDS: {shared cache} 3960** 3961** This routine enables or disables the sharing of the database cache 3962** and schema data structures between [database connection | connections] 3963** to the same database. Sharing is enabled if the argument is true 3964** and disabled if the argument is false. 3965** 3966** Cache sharing is enabled and disabled for an entire process. 3967** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 3968** sharing was enabled or disabled for each thread separately. 3969** 3970** The cache sharing mode set by this interface effects all subsequent 3971** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 3972** Existing database connections continue use the sharing mode 3973** that was in effect at the time they were opened. 3974** 3975** Virtual tables cannot be used with a shared cache. When shared 3976** cache is enabled, the [sqlite3_create_module()] API used to register 3977** virtual tables will always return an error. 3978** 3979** This routine returns [SQLITE_OK] if shared cache was enabled or disabled 3980** successfully. An [error code] is returned otherwise. 3981** 3982** Shared cache is disabled by default. But this might change in 3983** future releases of SQLite. Applications that care about shared 3984** cache setting should set it explicitly. 3985** 3986** See Also: [SQLite Shared-Cache Mode] 3987** 3988** Requirements: [H10331] [H10336] [H10337] [H10339] 3989*/ 3990int sqlite3_enable_shared_cache(int); 3991 3992/* 3993** CAPI3REF: Attempt To Free Heap Memory {H17340} <S30220> 3994** 3995** The sqlite3_release_memory() interface attempts to free N bytes 3996** of heap memory by deallocating non-essential memory allocations 3997** held by the database library. {END} Memory used to cache database 3998** pages to improve performance is an example of non-essential memory. 3999** sqlite3_release_memory() returns the number of bytes actually freed, 4000** which might be more or less than the amount requested. 4001** 4002** Requirements: [H17341] [H17342] 4003*/ 4004int sqlite3_release_memory(int); 4005 4006/* 4007** CAPI3REF: Impose A Limit On Heap Size {H17350} <S30220> 4008** 4009** The sqlite3_soft_heap_limit() interface places a "soft" limit 4010** on the amount of heap memory that may be allocated by SQLite. 4011** If an internal allocation is requested that would exceed the 4012** soft heap limit, [sqlite3_release_memory()] is invoked one or 4013** more times to free up some space before the allocation is performed. 4014** 4015** The limit is called "soft", because if [sqlite3_release_memory()] 4016** cannot free sufficient memory to prevent the limit from being exceeded, 4017** the memory is allocated anyway and the current operation proceeds. 4018** 4019** A negative or zero value for N means that there is no soft heap limit and 4020** [sqlite3_release_memory()] will only be called when memory is exhausted. 4021** The default value for the soft heap limit is zero. 4022** 4023** SQLite makes a best effort to honor the soft heap limit. 4024** But if the soft heap limit cannot be honored, execution will 4025** continue without error or notification. This is why the limit is 4026** called a "soft" limit. It is advisory only. 4027** 4028** Prior to SQLite version 3.5.0, this routine only constrained the memory 4029** allocated by a single thread - the same thread in which this routine 4030** runs. Beginning with SQLite version 3.5.0, the soft heap limit is 4031** applied to all threads. The value specified for the soft heap limit 4032** is an upper bound on the total memory allocation for all threads. In 4033** version 3.5.0 there is no mechanism for limiting the heap usage for 4034** individual threads. 4035** 4036** Requirements: 4037** [H16351] [H16352] [H16353] [H16354] [H16355] [H16358] 4038*/ 4039void sqlite3_soft_heap_limit(int); 4040 4041/* 4042** CAPI3REF: Extract Metadata About A Column Of A Table {H12850} <S60300> 4043** 4044** This routine returns metadata about a specific column of a specific 4045** database table accessible using the [database connection] handle 4046** passed as the first function argument. 4047** 4048** The column is identified by the second, third and fourth parameters to 4049** this function. The second parameter is either the name of the database 4050** (i.e. "main", "temp" or an attached database) containing the specified 4051** table or NULL. If it is NULL, then all attached databases are searched 4052** for the table using the same algorithm used by the database engine to 4053** resolve unqualified table references. 4054** 4055** The third and fourth parameters to this function are the table and column 4056** name of the desired column, respectively. Neither of these parameters 4057** may be NULL. 4058** 4059** Metadata is returned by writing to the memory locations passed as the 5th 4060** and subsequent parameters to this function. Any of these arguments may be 4061** NULL, in which case the corresponding element of metadata is omitted. 4062** 4063** <blockquote> 4064** <table border="1"> 4065** <tr><th> Parameter <th> Output<br>Type <th> Description 4066** 4067** <tr><td> 5th <td> const char* <td> Data type 4068** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4069** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4070** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4071** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4072** </table> 4073** </blockquote> 4074** 4075** The memory pointed to by the character pointers returned for the 4076** declaration type and collation sequence is valid only until the next 4077** call to any SQLite API function. 4078** 4079** If the specified table is actually a view, an [error code] is returned. 4080** 4081** If the specified column is "rowid", "oid" or "_rowid_" and an 4082** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4083** parameters are set for the explicitly declared column. If there is no 4084** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4085** parameters are set as follows: 4086** 4087** <pre> 4088** data type: "INTEGER" 4089** collation sequence: "BINARY" 4090** not null: 0 4091** primary key: 1 4092** auto increment: 0 4093** </pre> 4094** 4095** This function may load one or more schemas from database files. If an 4096** error occurs during this process, or if the requested table or column 4097** cannot be found, an [error code] is returned and an error message left 4098** in the [database connection] (to be retrieved using sqlite3_errmsg()). 4099** 4100** This API is only available if the library was compiled with the 4101** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4102*/ 4103int sqlite3_table_column_metadata( 4104 sqlite3 *db, /* Connection handle */ 4105 const char *zDbName, /* Database name or NULL */ 4106 const char *zTableName, /* Table name */ 4107 const char *zColumnName, /* Column name */ 4108 char const **pzDataType, /* OUTPUT: Declared data type */ 4109 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4110 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4111 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4112 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4113); 4114 4115/* 4116** CAPI3REF: Load An Extension {H12600} <S20500> 4117** 4118** This interface loads an SQLite extension library from the named file. 4119** 4120** {H12601} The sqlite3_load_extension() interface attempts to load an 4121** SQLite extension library contained in the file zFile. 4122** 4123** {H12602} The entry point is zProc. 4124** 4125** {H12603} zProc may be 0, in which case the name of the entry point 4126** defaults to "sqlite3_extension_init". 4127** 4128** {H12604} The sqlite3_load_extension() interface shall return 4129** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4130** 4131** {H12605} If an error occurs and pzErrMsg is not 0, then the 4132** [sqlite3_load_extension()] interface shall attempt to 4133** fill *pzErrMsg with error message text stored in memory 4134** obtained from [sqlite3_malloc()]. {END} The calling function 4135** should free this memory by calling [sqlite3_free()]. 4136** 4137** {H12606} Extension loading must be enabled using 4138** [sqlite3_enable_load_extension()] prior to calling this API, 4139** otherwise an error will be returned. 4140*/ 4141int sqlite3_load_extension( 4142 sqlite3 *db, /* Load the extension into this database connection */ 4143 const char *zFile, /* Name of the shared library containing extension */ 4144 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4145 char **pzErrMsg /* Put error message here if not 0 */ 4146); 4147 4148/* 4149** CAPI3REF: Enable Or Disable Extension Loading {H12620} <S20500> 4150** 4151** So as not to open security holes in older applications that are 4152** unprepared to deal with extension loading, and as a means of disabling 4153** extension loading while evaluating user-entered SQL, the following API 4154** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4155** 4156** Extension loading is off by default. See ticket #1863. 4157** 4158** {H12621} Call the sqlite3_enable_load_extension() routine with onoff==1 4159** to turn extension loading on and call it with onoff==0 to turn 4160** it back off again. 4161** 4162** {H12622} Extension loading is off by default. 4163*/ 4164int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4165 4166/* 4167** CAPI3REF: Automatically Load An Extensions {H12640} <S20500> 4168** 4169** This API can be invoked at program startup in order to register 4170** one or more statically linked extensions that will be available 4171** to all new [database connections]. {END} 4172** 4173** This routine stores a pointer to the extension in an array that is 4174** obtained from [sqlite3_malloc()]. If you run a memory leak checker 4175** on your program and it reports a leak because of this array, invoke 4176** [sqlite3_reset_auto_extension()] prior to shutdown to free the memory. 4177** 4178** {H12641} This function registers an extension entry point that is 4179** automatically invoked whenever a new [database connection] 4180** is opened using [sqlite3_open()], [sqlite3_open16()], 4181** or [sqlite3_open_v2()]. 4182** 4183** {H12642} Duplicate extensions are detected so calling this routine 4184** multiple times with the same extension is harmless. 4185** 4186** {H12643} This routine stores a pointer to the extension in an array 4187** that is obtained from [sqlite3_malloc()]. 4188** 4189** {H12644} Automatic extensions apply across all threads. 4190*/ 4191int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4192 4193/* 4194** CAPI3REF: Reset Automatic Extension Loading {H12660} <S20500> 4195** 4196** This function disables all previously registered automatic 4197** extensions. {END} It undoes the effect of all prior 4198** [sqlite3_auto_extension()] calls. 4199** 4200** {H12661} This function disables all previously registered 4201** automatic extensions. 4202** 4203** {H12662} This function disables automatic extensions in all threads. 4204*/ 4205void sqlite3_reset_auto_extension(void); 4206 4207/* 4208****** EXPERIMENTAL - subject to change without notice ************** 4209** 4210** The interface to the virtual-table mechanism is currently considered 4211** to be experimental. The interface might change in incompatible ways. 4212** If this is a problem for you, do not use the interface at this time. 4213** 4214** When the virtual-table mechanism stabilizes, we will declare the 4215** interface fixed, support it indefinitely, and remove this comment. 4216*/ 4217 4218/* 4219** Structures used by the virtual table interface 4220*/ 4221typedef struct sqlite3_vtab sqlite3_vtab; 4222typedef struct sqlite3_index_info sqlite3_index_info; 4223typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4224typedef struct sqlite3_module sqlite3_module; 4225 4226/* 4227** CAPI3REF: Virtual Table Object {H18000} <S20400> 4228** KEYWORDS: sqlite3_module {virtual table module} 4229** EXPERIMENTAL 4230** 4231** This structure, sometimes called a a "virtual table module", 4232** defines the implementation of a [virtual tables]. 4233** This structure consists mostly of methods for the module. 4234** 4235** A virtual table module is created by filling in a persistent 4236** instance of this structure and passing a pointer to that instance 4237** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4238** The registration remains valid until it is replaced by a different 4239** module or until the [database connection] closes. The content 4240** of this structure must not change while it is registered with 4241** any database connection. 4242*/ 4243struct sqlite3_module { 4244 int iVersion; 4245 int (*xCreate)(sqlite3*, void *pAux, 4246 int argc, const char *const*argv, 4247 sqlite3_vtab **ppVTab, char**); 4248 int (*xConnect)(sqlite3*, void *pAux, 4249 int argc, const char *const*argv, 4250 sqlite3_vtab **ppVTab, char**); 4251 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4252 int (*xDisconnect)(sqlite3_vtab *pVTab); 4253 int (*xDestroy)(sqlite3_vtab *pVTab); 4254 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4255 int (*xClose)(sqlite3_vtab_cursor*); 4256 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4257 int argc, sqlite3_value **argv); 4258 int (*xNext)(sqlite3_vtab_cursor*); 4259 int (*xEof)(sqlite3_vtab_cursor*); 4260 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4261 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4262 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4263 int (*xBegin)(sqlite3_vtab *pVTab); 4264 int (*xSync)(sqlite3_vtab *pVTab); 4265 int (*xCommit)(sqlite3_vtab *pVTab); 4266 int (*xRollback)(sqlite3_vtab *pVTab); 4267 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4268 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4269 void **ppArg); 4270 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4271}; 4272 4273/* 4274** CAPI3REF: Virtual Table Indexing Information {H18100} <S20400> 4275** KEYWORDS: sqlite3_index_info 4276** EXPERIMENTAL 4277** 4278** The sqlite3_index_info structure and its substructures is used to 4279** pass information into and receive the reply from the [xBestIndex] 4280** method of a [virtual table module]. The fields under **Inputs** are the 4281** inputs to xBestIndex and are read-only. xBestIndex inserts its 4282** results into the **Outputs** fields. 4283** 4284** The aConstraint[] array records WHERE clause constraints of the form: 4285** 4286** <pre>column OP expr</pre> 4287** 4288** where OP is =, <, <=, >, or >=. The particular operator is 4289** stored in aConstraint[].op. The index of the column is stored in 4290** aConstraint[].iColumn. aConstraint[].usable is TRUE if the 4291** expr on the right-hand side can be evaluated (and thus the constraint 4292** is usable) and false if it cannot. 4293** 4294** The optimizer automatically inverts terms of the form "expr OP column" 4295** and makes other simplifications to the WHERE clause in an attempt to 4296** get as many WHERE clause terms into the form shown above as possible. 4297** The aConstraint[] array only reports WHERE clause terms in the correct 4298** form that refer to the particular virtual table being queried. 4299** 4300** Information about the ORDER BY clause is stored in aOrderBy[]. 4301** Each term of aOrderBy records a column of the ORDER BY clause. 4302** 4303** The [xBestIndex] method must fill aConstraintUsage[] with information 4304** about what parameters to pass to xFilter. If argvIndex>0 then 4305** the right-hand side of the corresponding aConstraint[] is evaluated 4306** and becomes the argvIndex-th entry in argv. If aConstraintUsage[].omit 4307** is true, then the constraint is assumed to be fully handled by the 4308** virtual table and is not checked again by SQLite. 4309** 4310** The idxNum and idxPtr values are recorded and passed into the 4311** [xFilter] method. 4312** [sqlite3_free()] is used to free idxPtr if and only iff 4313** needToFreeIdxPtr is true. 4314** 4315** The orderByConsumed means that output from [xFilter]/[xNext] will occur in 4316** the correct order to satisfy the ORDER BY clause so that no separate 4317** sorting step is required. 4318** 4319** The estimatedCost value is an estimate of the cost of doing the 4320** particular lookup. A full scan of a table with N entries should have 4321** a cost of N. A binary search of a table of N entries should have a 4322** cost of approximately log(N). 4323*/ 4324struct sqlite3_index_info { 4325 /* Inputs */ 4326 int nConstraint; /* Number of entries in aConstraint */ 4327 struct sqlite3_index_constraint { 4328 int iColumn; /* Column on left-hand side of constraint */ 4329 unsigned char op; /* Constraint operator */ 4330 unsigned char usable; /* True if this constraint is usable */ 4331 int iTermOffset; /* Used internally - xBestIndex should ignore */ 4332 } *aConstraint; /* Table of WHERE clause constraints */ 4333 int nOrderBy; /* Number of terms in the ORDER BY clause */ 4334 struct sqlite3_index_orderby { 4335 int iColumn; /* Column number */ 4336 unsigned char desc; /* True for DESC. False for ASC. */ 4337 } *aOrderBy; /* The ORDER BY clause */ 4338 /* Outputs */ 4339 struct sqlite3_index_constraint_usage { 4340 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 4341 unsigned char omit; /* Do not code a test for this constraint */ 4342 } *aConstraintUsage; 4343 int idxNum; /* Number used to identify the index */ 4344 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 4345 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 4346 int orderByConsumed; /* True if output is already ordered */ 4347 double estimatedCost; /* Estimated cost of using this index */ 4348}; 4349#define SQLITE_INDEX_CONSTRAINT_EQ 2 4350#define SQLITE_INDEX_CONSTRAINT_GT 4 4351#define SQLITE_INDEX_CONSTRAINT_LE 8 4352#define SQLITE_INDEX_CONSTRAINT_LT 16 4353#define SQLITE_INDEX_CONSTRAINT_GE 32 4354#define SQLITE_INDEX_CONSTRAINT_MATCH 64 4355 4356/* 4357** CAPI3REF: Register A Virtual Table Implementation {H18200} <S20400> 4358** EXPERIMENTAL 4359** 4360** This routine is used to register a new [virtual table module] name. 4361** Module names must be registered before 4362** creating a new [virtual table] using the module, or before using a 4363** preexisting [virtual table] for the module. 4364** 4365** The module name is registered on the [database connection] specified 4366** by the first parameter. The name of the module is given by the 4367** second parameter. The third parameter is a pointer to 4368** the implementation of the [virtual table module]. The fourth 4369** parameter is an arbitrary client data pointer that is passed through 4370** into the [xCreate] and [xConnect] methods of the virtual table module 4371** when a new virtual table is be being created or reinitialized. 4372** 4373** This interface has exactly the same effect as calling 4374** [sqlite3_create_module_v2()] with a NULL client data destructor. 4375*/ 4376SQLITE_EXPERIMENTAL int sqlite3_create_module( 4377 sqlite3 *db, /* SQLite connection to register module with */ 4378 const char *zName, /* Name of the module */ 4379 const sqlite3_module *p, /* Methods for the module */ 4380 void *pClientData /* Client data for xCreate/xConnect */ 4381); 4382 4383/* 4384** CAPI3REF: Register A Virtual Table Implementation {H18210} <S20400> 4385** EXPERIMENTAL 4386** 4387** This routine is identical to the [sqlite3_create_module()] method, 4388** except that it has an extra parameter to specify 4389** a destructor function for the client data pointer. SQLite will 4390** invoke the destructor function (if it is not NULL) when SQLite 4391** no longer needs the pClientData pointer. 4392*/ 4393SQLITE_EXPERIMENTAL int sqlite3_create_module_v2( 4394 sqlite3 *db, /* SQLite connection to register module with */ 4395 const char *zName, /* Name of the module */ 4396 const sqlite3_module *p, /* Methods for the module */ 4397 void *pClientData, /* Client data for xCreate/xConnect */ 4398 void(*xDestroy)(void*) /* Module destructor function */ 4399); 4400 4401/* 4402** CAPI3REF: Virtual Table Instance Object {H18010} <S20400> 4403** KEYWORDS: sqlite3_vtab 4404** EXPERIMENTAL 4405** 4406** Every [virtual table module] implementation uses a subclass 4407** of the following structure to describe a particular instance 4408** of the [virtual table]. Each subclass will 4409** be tailored to the specific needs of the module implementation. 4410** The purpose of this superclass is to define certain fields that are 4411** common to all module implementations. 4412** 4413** Virtual tables methods can set an error message by assigning a 4414** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 4415** take care that any prior string is freed by a call to [sqlite3_free()] 4416** prior to assigning a new string to zErrMsg. After the error message 4417** is delivered up to the client application, the string will be automatically 4418** freed by sqlite3_free() and the zErrMsg field will be zeroed. 4419*/ 4420struct sqlite3_vtab { 4421 const sqlite3_module *pModule; /* The module for this virtual table */ 4422 int nRef; /* NO LONGER USED */ 4423 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 4424 /* Virtual table implementations will typically add additional fields */ 4425}; 4426 4427/* 4428** CAPI3REF: Virtual Table Cursor Object {H18020} <S20400> 4429** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 4430** EXPERIMENTAL 4431** 4432** Every [virtual table module] implementation uses a subclass of the 4433** following structure to describe cursors that point into the 4434** [virtual table] and are used 4435** to loop through the virtual table. Cursors are created using the 4436** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 4437** by the [sqlite3_module.xClose | xClose] method. Cussors are used 4438** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 4439** of the module. Each module implementation will define 4440** the content of a cursor structure to suit its own needs. 4441** 4442** This superclass exists in order to define fields of the cursor that 4443** are common to all implementations. 4444*/ 4445struct sqlite3_vtab_cursor { 4446 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 4447 /* Virtual table implementations will typically add additional fields */ 4448}; 4449 4450/* 4451** CAPI3REF: Declare The Schema Of A Virtual Table {H18280} <S20400> 4452** EXPERIMENTAL 4453** 4454** The [xCreate] and [xConnect] methods of a 4455** [virtual table module] call this interface 4456** to declare the format (the names and datatypes of the columns) of 4457** the virtual tables they implement. 4458*/ 4459SQLITE_EXPERIMENTAL int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 4460 4461/* 4462** CAPI3REF: Overload A Function For A Virtual Table {H18300} <S20400> 4463** EXPERIMENTAL 4464** 4465** Virtual tables can provide alternative implementations of functions 4466** using the [xFindFunction] method of the [virtual table module]. 4467** But global versions of those functions 4468** must exist in order to be overloaded. 4469** 4470** This API makes sure a global version of a function with a particular 4471** name and number of parameters exists. If no such function exists 4472** before this API is called, a new function is created. The implementation 4473** of the new function always causes an exception to be thrown. So 4474** the new function is not good for anything by itself. Its only 4475** purpose is to be a placeholder function that can be overloaded 4476** by a [virtual table]. 4477*/ 4478SQLITE_EXPERIMENTAL int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 4479 4480/* 4481** The interface to the virtual-table mechanism defined above (back up 4482** to a comment remarkably similar to this one) is currently considered 4483** to be experimental. The interface might change in incompatible ways. 4484** If this is a problem for you, do not use the interface at this time. 4485** 4486** When the virtual-table mechanism stabilizes, we will declare the 4487** interface fixed, support it indefinitely, and remove this comment. 4488** 4489****** EXPERIMENTAL - subject to change without notice ************** 4490*/ 4491 4492/* 4493** CAPI3REF: A Handle To An Open BLOB {H17800} <S30230> 4494** KEYWORDS: {BLOB handle} {BLOB handles} 4495** 4496** An instance of this object represents an open BLOB on which 4497** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 4498** Objects of this type are created by [sqlite3_blob_open()] 4499** and destroyed by [sqlite3_blob_close()]. 4500** The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 4501** can be used to read or write small subsections of the BLOB. 4502** The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 4503*/ 4504typedef struct sqlite3_blob sqlite3_blob; 4505 4506/* 4507** CAPI3REF: Open A BLOB For Incremental I/O {H17810} <S30230> 4508** 4509** This interfaces opens a [BLOB handle | handle] to the BLOB located 4510** in row iRow, column zColumn, table zTable in database zDb; 4511** in other words, the same BLOB that would be selected by: 4512** 4513** <pre> 4514** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 4515** </pre> {END} 4516** 4517** If the flags parameter is non-zero, then the BLOB is opened for read 4518** and write access. If it is zero, the BLOB is opened for read access. 4519** It is not possible to open a column that is part of an index or primary 4520** key for writing. ^If [foreign key constraints] are enabled, it is 4521** not possible to open a column that is part of a [child key] for writing. 4522** 4523** Note that the database name is not the filename that contains 4524** the database but rather the symbolic name of the database that 4525** is assigned when the database is connected using [ATTACH]. 4526** For the main database file, the database name is "main". 4527** For TEMP tables, the database name is "temp". 4528** 4529** On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 4530** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 4531** to be a null pointer. 4532** This function sets the [database connection] error code and message 4533** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 4534** functions. Note that the *ppBlob variable is always initialized in a 4535** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 4536** regardless of the success or failure of this routine. 4537** 4538** If the row that a BLOB handle points to is modified by an 4539** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 4540** then the BLOB handle is marked as "expired". 4541** This is true if any column of the row is changed, even a column 4542** other than the one the BLOB handle is open on. 4543** Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 4544** a expired BLOB handle fail with an return code of [SQLITE_ABORT]. 4545** Changes written into a BLOB prior to the BLOB expiring are not 4546** rollback by the expiration of the BLOB. Such changes will eventually 4547** commit if the transaction continues to completion. 4548** 4549** Use the [sqlite3_blob_bytes()] interface to determine the size of 4550** the opened blob. The size of a blob may not be changed by this 4551** interface. Use the [UPDATE] SQL command to change the size of a 4552** blob. 4553** 4554** The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 4555** and the built-in [zeroblob] SQL function can be used, if desired, 4556** to create an empty, zero-filled blob in which to read or write using 4557** this interface. 4558** 4559** To avoid a resource leak, every open [BLOB handle] should eventually 4560** be released by a call to [sqlite3_blob_close()]. 4561** 4562** Requirements: 4563** [H17813] [H17814] [H17816] [H17819] [H17821] [H17824] 4564*/ 4565int sqlite3_blob_open( 4566 sqlite3*, 4567 const char *zDb, 4568 const char *zTable, 4569 const char *zColumn, 4570 sqlite3_int64 iRow, 4571 int flags, 4572 sqlite3_blob **ppBlob 4573); 4574 4575/* 4576** CAPI3REF: Close A BLOB Handle {H17830} <S30230> 4577** 4578** Closes an open [BLOB handle]. 4579** 4580** Closing a BLOB shall cause the current transaction to commit 4581** if there are no other BLOBs, no pending prepared statements, and the 4582** database connection is in [autocommit mode]. 4583** If any writes were made to the BLOB, they might be held in cache 4584** until the close operation if they will fit. 4585** 4586** Closing the BLOB often forces the changes 4587** out to disk and so if any I/O errors occur, they will likely occur 4588** at the time when the BLOB is closed. Any errors that occur during 4589** closing are reported as a non-zero return value. 4590** 4591** The BLOB is closed unconditionally. Even if this routine returns 4592** an error code, the BLOB is still closed. 4593** 4594** Calling this routine with a null pointer (which as would be returned 4595** by failed call to [sqlite3_blob_open()]) is a harmless no-op. 4596** 4597** Requirements: 4598** [H17833] [H17836] [H17839] 4599*/ 4600int sqlite3_blob_close(sqlite3_blob *); 4601 4602/* 4603** CAPI3REF: Return The Size Of An Open BLOB {H17840} <S30230> 4604** 4605** Returns the size in bytes of the BLOB accessible via the 4606** successfully opened [BLOB handle] in its only argument. The 4607** incremental blob I/O routines can only read or overwriting existing 4608** blob content; they cannot change the size of a blob. 4609** 4610** This routine only works on a [BLOB handle] which has been created 4611** by a prior successful call to [sqlite3_blob_open()] and which has not 4612** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4613** to this routine results in undefined and probably undesirable behavior. 4614** 4615** Requirements: 4616** [H17843] 4617*/ 4618int sqlite3_blob_bytes(sqlite3_blob *); 4619 4620/* 4621** CAPI3REF: Read Data From A BLOB Incrementally {H17850} <S30230> 4622** 4623** This function is used to read data from an open [BLOB handle] into a 4624** caller-supplied buffer. N bytes of data are copied into buffer Z 4625** from the open BLOB, starting at offset iOffset. 4626** 4627** If offset iOffset is less than N bytes from the end of the BLOB, 4628** [SQLITE_ERROR] is returned and no data is read. If N or iOffset is 4629** less than zero, [SQLITE_ERROR] is returned and no data is read. 4630** The size of the blob (and hence the maximum value of N+iOffset) 4631** can be determined using the [sqlite3_blob_bytes()] interface. 4632** 4633** An attempt to read from an expired [BLOB handle] fails with an 4634** error code of [SQLITE_ABORT]. 4635** 4636** On success, SQLITE_OK is returned. 4637** Otherwise, an [error code] or an [extended error code] is returned. 4638** 4639** This routine only works on a [BLOB handle] which has been created 4640** by a prior successful call to [sqlite3_blob_open()] and which has not 4641** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4642** to this routine results in undefined and probably undesirable behavior. 4643** 4644** See also: [sqlite3_blob_write()]. 4645** 4646** Requirements: 4647** [H17853] [H17856] [H17859] [H17862] [H17863] [H17865] [H17868] 4648*/ 4649int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 4650 4651/* 4652** CAPI3REF: Write Data Into A BLOB Incrementally {H17870} <S30230> 4653** 4654** This function is used to write data into an open [BLOB handle] from a 4655** caller-supplied buffer. N bytes of data are copied from the buffer Z 4656** into the open BLOB, starting at offset iOffset. 4657** 4658** If the [BLOB handle] passed as the first argument was not opened for 4659** writing (the flags parameter to [sqlite3_blob_open()] was zero), 4660** this function returns [SQLITE_READONLY]. 4661** 4662** This function may only modify the contents of the BLOB; it is 4663** not possible to increase the size of a BLOB using this API. 4664** If offset iOffset is less than N bytes from the end of the BLOB, 4665** [SQLITE_ERROR] is returned and no data is written. If N is 4666** less than zero [SQLITE_ERROR] is returned and no data is written. 4667** The size of the BLOB (and hence the maximum value of N+iOffset) 4668** can be determined using the [sqlite3_blob_bytes()] interface. 4669** 4670** An attempt to write to an expired [BLOB handle] fails with an 4671** error code of [SQLITE_ABORT]. Writes to the BLOB that occurred 4672** before the [BLOB handle] expired are not rolled back by the 4673** expiration of the handle, though of course those changes might 4674** have been overwritten by the statement that expired the BLOB handle 4675** or by other independent statements. 4676** 4677** On success, SQLITE_OK is returned. 4678** Otherwise, an [error code] or an [extended error code] is returned. 4679** 4680** This routine only works on a [BLOB handle] which has been created 4681** by a prior successful call to [sqlite3_blob_open()] and which has not 4682** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4683** to this routine results in undefined and probably undesirable behavior. 4684** 4685** See also: [sqlite3_blob_read()]. 4686** 4687** Requirements: 4688** [H17873] [H17874] [H17875] [H17876] [H17877] [H17879] [H17882] [H17885] 4689** [H17888] 4690*/ 4691int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 4692 4693/* 4694** CAPI3REF: Virtual File System Objects {H11200} <S20100> 4695** 4696** A virtual filesystem (VFS) is an [sqlite3_vfs] object 4697** that SQLite uses to interact 4698** with the underlying operating system. Most SQLite builds come with a 4699** single default VFS that is appropriate for the host computer. 4700** New VFSes can be registered and existing VFSes can be unregistered. 4701** The following interfaces are provided. 4702** 4703** The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 4704** Names are case sensitive. 4705** Names are zero-terminated UTF-8 strings. 4706** If there is no match, a NULL pointer is returned. 4707** If zVfsName is NULL then the default VFS is returned. 4708** 4709** New VFSes are registered with sqlite3_vfs_register(). 4710** Each new VFS becomes the default VFS if the makeDflt flag is set. 4711** The same VFS can be registered multiple times without injury. 4712** To make an existing VFS into the default VFS, register it again 4713** with the makeDflt flag set. If two different VFSes with the 4714** same name are registered, the behavior is undefined. If a 4715** VFS is registered with a name that is NULL or an empty string, 4716** then the behavior is undefined. 4717** 4718** Unregister a VFS with the sqlite3_vfs_unregister() interface. 4719** If the default VFS is unregistered, another VFS is chosen as 4720** the default. The choice for the new VFS is arbitrary. 4721** 4722** Requirements: 4723** [H11203] [H11206] [H11209] [H11212] [H11215] [H11218] 4724*/ 4725sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 4726int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 4727int sqlite3_vfs_unregister(sqlite3_vfs*); 4728 4729/* 4730** CAPI3REF: Mutexes {H17000} <S20000> 4731** 4732** The SQLite core uses these routines for thread 4733** synchronization. Though they are intended for internal 4734** use by SQLite, code that links against SQLite is 4735** permitted to use any of these routines. 4736** 4737** The SQLite source code contains multiple implementations 4738** of these mutex routines. An appropriate implementation 4739** is selected automatically at compile-time. The following 4740** implementations are available in the SQLite core: 4741** 4742** <ul> 4743** <li> SQLITE_MUTEX_OS2 4744** <li> SQLITE_MUTEX_PTHREAD 4745** <li> SQLITE_MUTEX_W32 4746** <li> SQLITE_MUTEX_NOOP 4747** </ul> 4748** 4749** The SQLITE_MUTEX_NOOP implementation is a set of routines 4750** that does no real locking and is appropriate for use in 4751** a single-threaded application. The SQLITE_MUTEX_OS2, 4752** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations 4753** are appropriate for use on OS/2, Unix, and Windows. 4754** 4755** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 4756** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 4757** implementation is included with the library. In this case the 4758** application must supply a custom mutex implementation using the 4759** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 4760** before calling sqlite3_initialize() or any other public sqlite3_ 4761** function that calls sqlite3_initialize(). 4762** 4763** {H17011} The sqlite3_mutex_alloc() routine allocates a new 4764** mutex and returns a pointer to it. {H17012} If it returns NULL 4765** that means that a mutex could not be allocated. {H17013} SQLite 4766** will unwind its stack and return an error. {H17014} The argument 4767** to sqlite3_mutex_alloc() is one of these integer constants: 4768** 4769** <ul> 4770** <li> SQLITE_MUTEX_FAST 4771** <li> SQLITE_MUTEX_RECURSIVE 4772** <li> SQLITE_MUTEX_STATIC_MASTER 4773** <li> SQLITE_MUTEX_STATIC_MEM 4774** <li> SQLITE_MUTEX_STATIC_MEM2 4775** <li> SQLITE_MUTEX_STATIC_PRNG 4776** <li> SQLITE_MUTEX_STATIC_LRU 4777** <li> SQLITE_MUTEX_STATIC_LRU2 4778** </ul> 4779** 4780** {H17015} The first two constants cause sqlite3_mutex_alloc() to create 4781** a new mutex. The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 4782** is used but not necessarily so when SQLITE_MUTEX_FAST is used. {END} 4783** The mutex implementation does not need to make a distinction 4784** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 4785** not want to. {H17016} But SQLite will only request a recursive mutex in 4786** cases where it really needs one. {END} If a faster non-recursive mutex 4787** implementation is available on the host platform, the mutex subsystem 4788** might return such a mutex in response to SQLITE_MUTEX_FAST. 4789** 4790** {H17017} The other allowed parameters to sqlite3_mutex_alloc() each return 4791** a pointer to a static preexisting mutex. {END} Six static mutexes are 4792** used by the current version of SQLite. Future versions of SQLite 4793** may add additional static mutexes. Static mutexes are for internal 4794** use by SQLite only. Applications that use SQLite mutexes should 4795** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 4796** SQLITE_MUTEX_RECURSIVE. 4797** 4798** {H17018} Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 4799** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 4800** returns a different mutex on every call. {H17034} But for the static 4801** mutex types, the same mutex is returned on every call that has 4802** the same type number. 4803** 4804** {H17019} The sqlite3_mutex_free() routine deallocates a previously 4805** allocated dynamic mutex. {H17020} SQLite is careful to deallocate every 4806** dynamic mutex that it allocates. {A17021} The dynamic mutexes must not be in 4807** use when they are deallocated. {A17022} Attempting to deallocate a static 4808** mutex results in undefined behavior. {H17023} SQLite never deallocates 4809** a static mutex. {END} 4810** 4811** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 4812** to enter a mutex. {H17024} If another thread is already within the mutex, 4813** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 4814** SQLITE_BUSY. {H17025} The sqlite3_mutex_try() interface returns [SQLITE_OK] 4815** upon successful entry. {H17026} Mutexes created using 4816** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 4817** {H17027} In such cases the, 4818** mutex must be exited an equal number of times before another thread 4819** can enter. {A17028} If the same thread tries to enter any other 4820** kind of mutex more than once, the behavior is undefined. 4821** {H17029} SQLite will never exhibit 4822** such behavior in its own use of mutexes. 4823** 4824** Some systems (for example, Windows 95) do not support the operation 4825** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 4826** will always return SQLITE_BUSY. {H17030} The SQLite core only ever uses 4827** sqlite3_mutex_try() as an optimization so this is acceptable behavior. 4828** 4829** {H17031} The sqlite3_mutex_leave() routine exits a mutex that was 4830** previously entered by the same thread. {A17032} The behavior 4831** is undefined if the mutex is not currently entered by the 4832** calling thread or is not currently allocated. {H17033} SQLite will 4833** never do either. {END} 4834** 4835** If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 4836** sqlite3_mutex_leave() is a NULL pointer, then all three routines 4837** behave as no-ops. 4838** 4839** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 4840*/ 4841sqlite3_mutex *sqlite3_mutex_alloc(int); 4842void sqlite3_mutex_free(sqlite3_mutex*); 4843void sqlite3_mutex_enter(sqlite3_mutex*); 4844int sqlite3_mutex_try(sqlite3_mutex*); 4845void sqlite3_mutex_leave(sqlite3_mutex*); 4846 4847/* 4848** CAPI3REF: Mutex Methods Object {H17120} <S20130> 4849** EXPERIMENTAL 4850** 4851** An instance of this structure defines the low-level routines 4852** used to allocate and use mutexes. 4853** 4854** Usually, the default mutex implementations provided by SQLite are 4855** sufficient, however the user has the option of substituting a custom 4856** implementation for specialized deployments or systems for which SQLite 4857** does not provide a suitable implementation. In this case, the user 4858** creates and populates an instance of this structure to pass 4859** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 4860** Additionally, an instance of this structure can be used as an 4861** output variable when querying the system for the current mutex 4862** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 4863** 4864** The xMutexInit method defined by this structure is invoked as 4865** part of system initialization by the sqlite3_initialize() function. 4866** {H17001} The xMutexInit routine shall be called by SQLite once for each 4867** effective call to [sqlite3_initialize()]. 4868** 4869** The xMutexEnd method defined by this structure is invoked as 4870** part of system shutdown by the sqlite3_shutdown() function. The 4871** implementation of this method is expected to release all outstanding 4872** resources obtained by the mutex methods implementation, especially 4873** those obtained by the xMutexInit method. {H17003} The xMutexEnd() 4874** interface shall be invoked once for each call to [sqlite3_shutdown()]. 4875** 4876** The remaining seven methods defined by this structure (xMutexAlloc, 4877** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 4878** xMutexNotheld) implement the following interfaces (respectively): 4879** 4880** <ul> 4881** <li> [sqlite3_mutex_alloc()] </li> 4882** <li> [sqlite3_mutex_free()] </li> 4883** <li> [sqlite3_mutex_enter()] </li> 4884** <li> [sqlite3_mutex_try()] </li> 4885** <li> [sqlite3_mutex_leave()] </li> 4886** <li> [sqlite3_mutex_held()] </li> 4887** <li> [sqlite3_mutex_notheld()] </li> 4888** </ul> 4889** 4890** The only difference is that the public sqlite3_XXX functions enumerated 4891** above silently ignore any invocations that pass a NULL pointer instead 4892** of a valid mutex handle. The implementations of the methods defined 4893** by this structure are not required to handle this case, the results 4894** of passing a NULL pointer instead of a valid mutex handle are undefined 4895** (i.e. it is acceptable to provide an implementation that segfaults if 4896** it is passed a NULL pointer). 4897** 4898** The xMutexInit() method must be threadsafe. It must be harmless to 4899** invoke xMutexInit() mutiple times within the same process and without 4900** intervening calls to xMutexEnd(). Second and subsequent calls to 4901** xMutexInit() must be no-ops. 4902** 4903** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 4904** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 4905** allocation for a static mutex. However xMutexAlloc() may use SQLite 4906** memory allocation for a fast or recursive mutex. 4907** 4908** SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 4909** called, but only if the prior call to xMutexInit returned SQLITE_OK. 4910** If xMutexInit fails in any way, it is expected to clean up after itself 4911** prior to returning. 4912*/ 4913typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 4914struct sqlite3_mutex_methods { 4915 int (*xMutexInit)(void); 4916 int (*xMutexEnd)(void); 4917 sqlite3_mutex *(*xMutexAlloc)(int); 4918 void (*xMutexFree)(sqlite3_mutex *); 4919 void (*xMutexEnter)(sqlite3_mutex *); 4920 int (*xMutexTry)(sqlite3_mutex *); 4921 void (*xMutexLeave)(sqlite3_mutex *); 4922 int (*xMutexHeld)(sqlite3_mutex *); 4923 int (*xMutexNotheld)(sqlite3_mutex *); 4924}; 4925 4926/* 4927** CAPI3REF: Mutex Verification Routines {H17080} <S20130> <S30800> 4928** 4929** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 4930** are intended for use inside assert() statements. {H17081} The SQLite core 4931** never uses these routines except inside an assert() and applications 4932** are advised to follow the lead of the core. {H17082} The core only 4933** provides implementations for these routines when it is compiled 4934** with the SQLITE_DEBUG flag. {A17087} External mutex implementations 4935** are only required to provide these routines if SQLITE_DEBUG is 4936** defined and if NDEBUG is not defined. 4937** 4938** {H17083} These routines should return true if the mutex in their argument 4939** is held or not held, respectively, by the calling thread. 4940** 4941** {X17084} The implementation is not required to provided versions of these 4942** routines that actually work. If the implementation does not provide working 4943** versions of these routines, it should at least provide stubs that always 4944** return true so that one does not get spurious assertion failures. 4945** 4946** {H17085} If the argument to sqlite3_mutex_held() is a NULL pointer then 4947** the routine should return 1. {END} This seems counter-intuitive since 4948** clearly the mutex cannot be held if it does not exist. But the 4949** the reason the mutex does not exist is because the build is not 4950** using mutexes. And we do not want the assert() containing the 4951** call to sqlite3_mutex_held() to fail, so a non-zero return is 4952** the appropriate thing to do. {H17086} The sqlite3_mutex_notheld() 4953** interface should also return 1 when given a NULL pointer. 4954*/ 4955int sqlite3_mutex_held(sqlite3_mutex*); 4956int sqlite3_mutex_notheld(sqlite3_mutex*); 4957 4958/* 4959** CAPI3REF: Mutex Types {H17001} <H17000> 4960** 4961** The [sqlite3_mutex_alloc()] interface takes a single argument 4962** which is one of these integer constants. 4963** 4964** The set of static mutexes may change from one SQLite release to the 4965** next. Applications that override the built-in mutex logic must be 4966** prepared to accommodate additional static mutexes. 4967*/ 4968#define SQLITE_MUTEX_FAST 0 4969#define SQLITE_MUTEX_RECURSIVE 1 4970#define SQLITE_MUTEX_STATIC_MASTER 2 4971#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 4972#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 4973#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 4974#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 4975#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 4976#define SQLITE_MUTEX_STATIC_LRU2 7 /* lru page list */ 4977 4978/* 4979** CAPI3REF: Retrieve the mutex for a database connection {H17002} <H17000> 4980** 4981** This interface returns a pointer the [sqlite3_mutex] object that 4982** serializes access to the [database connection] given in the argument 4983** when the [threading mode] is Serialized. 4984** If the [threading mode] is Single-thread or Multi-thread then this 4985** routine returns a NULL pointer. 4986*/ 4987sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 4988 4989/* 4990** CAPI3REF: Low-Level Control Of Database Files {H11300} <S30800> 4991** 4992** {H11301} The [sqlite3_file_control()] interface makes a direct call to the 4993** xFileControl method for the [sqlite3_io_methods] object associated 4994** with a particular database identified by the second argument. {H11302} The 4995** name of the database is the name assigned to the database by the 4996** <a href="lang_attach.html">ATTACH</a> SQL command that opened the 4997** database. {H11303} To control the main database file, use the name "main" 4998** or a NULL pointer. {H11304} The third and fourth parameters to this routine 4999** are passed directly through to the second and third parameters of 5000** the xFileControl method. {H11305} The return value of the xFileControl 5001** method becomes the return value of this routine. 5002** 5003** {H11306} If the second parameter (zDbName) does not match the name of any 5004** open database file, then SQLITE_ERROR is returned. {H11307} This error 5005** code is not remembered and will not be recalled by [sqlite3_errcode()] 5006** or [sqlite3_errmsg()]. {A11308} The underlying xFileControl method might 5007** also return SQLITE_ERROR. {A11309} There is no way to distinguish between 5008** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5009** xFileControl method. {END} 5010** 5011** See also: [SQLITE_FCNTL_LOCKSTATE] 5012*/ 5013int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5014 5015/* 5016** CAPI3REF: Testing Interface {H11400} <S30800> 5017** 5018** The sqlite3_test_control() interface is used to read out internal 5019** state of SQLite and to inject faults into SQLite for testing 5020** purposes. The first parameter is an operation code that determines 5021** the number, meaning, and operation of all subsequent parameters. 5022** 5023** This interface is not for use by applications. It exists solely 5024** for verifying the correct operation of the SQLite library. Depending 5025** on how the SQLite library is compiled, this interface might not exist. 5026** 5027** The details of the operation codes, their meanings, the parameters 5028** they take, and what they do are all subject to change without notice. 5029** Unlike most of the SQLite API, this function is not guaranteed to 5030** operate consistently from one release to the next. 5031*/ 5032int sqlite3_test_control(int op, ...); 5033 5034/* 5035** CAPI3REF: Testing Interface Operation Codes {H11410} <H11400> 5036** 5037** These constants are the valid operation code parameters used 5038** as the first argument to [sqlite3_test_control()]. 5039** 5040** These parameters and their meanings are subject to change 5041** without notice. These values are for testing purposes only. 5042** Applications should not use any of these parameters or the 5043** [sqlite3_test_control()] interface. 5044*/ 5045#define SQLITE_TESTCTRL_PRNG_SAVE 5 5046#define SQLITE_TESTCTRL_PRNG_RESTORE 6 5047#define SQLITE_TESTCTRL_PRNG_RESET 7 5048#define SQLITE_TESTCTRL_BITVEC_TEST 8 5049#define SQLITE_TESTCTRL_FAULT_INSTALL 9 5050#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5051#define SQLITE_TESTCTRL_PENDING_BYTE 11 5052#define SQLITE_TESTCTRL_ASSERT 12 5053#define SQLITE_TESTCTRL_ALWAYS 13 5054#define SQLITE_TESTCTRL_RESERVE 14 5055 5056/* 5057** CAPI3REF: SQLite Runtime Status {H17200} <S60200> 5058** EXPERIMENTAL 5059** 5060** This interface is used to retrieve runtime status information 5061** about the preformance of SQLite, and optionally to reset various 5062** highwater marks. The first argument is an integer code for 5063** the specific parameter to measure. Recognized integer codes 5064** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...]. 5065** The current value of the parameter is returned into *pCurrent. 5066** The highest recorded value is returned in *pHighwater. If the 5067** resetFlag is true, then the highest record value is reset after 5068** *pHighwater is written. Some parameters do not record the highest 5069** value. For those parameters 5070** nothing is written into *pHighwater and the resetFlag is ignored. 5071** Other parameters record only the highwater mark and not the current 5072** value. For these latter parameters nothing is written into *pCurrent. 5073** 5074** This routine returns SQLITE_OK on success and a non-zero 5075** [error code] on failure. 5076** 5077** This routine is threadsafe but is not atomic. This routine can be 5078** called while other threads are running the same or different SQLite 5079** interfaces. However the values returned in *pCurrent and 5080** *pHighwater reflect the status of SQLite at different points in time 5081** and it is possible that another thread might change the parameter 5082** in between the times when *pCurrent and *pHighwater are written. 5083** 5084** See also: [sqlite3_db_status()] 5085*/ 5086SQLITE_EXPERIMENTAL int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 5087 5088 5089/* 5090** CAPI3REF: Status Parameters {H17250} <H17200> 5091** EXPERIMENTAL 5092** 5093** These integer constants designate various run-time status parameters 5094** that can be returned by [sqlite3_status()]. 5095** 5096** <dl> 5097** <dt>SQLITE_STATUS_MEMORY_USED</dt> 5098** <dd>This parameter is the current amount of memory checked out 5099** using [sqlite3_malloc()], either directly or indirectly. The 5100** figure includes calls made to [sqlite3_malloc()] by the application 5101** and internal memory usage by the SQLite library. Scratch memory 5102** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 5103** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 5104** this parameter. The amount returned is the sum of the allocation 5105** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd> 5106** 5107** <dt>SQLITE_STATUS_MALLOC_SIZE</dt> 5108** <dd>This parameter records the largest memory allocation request 5109** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 5110** internal equivalents). Only the value returned in the 5111** *pHighwater parameter to [sqlite3_status()] is of interest. 5112** The value written into the *pCurrent parameter is undefined.</dd> 5113** 5114** <dt>SQLITE_STATUS_PAGECACHE_USED</dt> 5115** <dd>This parameter returns the number of pages used out of the 5116** [pagecache memory allocator] that was configured using 5117** [SQLITE_CONFIG_PAGECACHE]. The 5118** value returned is in pages, not in bytes.</dd> 5119** 5120** <dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5121** <dd>This parameter returns the number of bytes of page cache 5122** allocation which could not be statisfied by the [SQLITE_CONFIG_PAGECACHE] 5123** buffer and where forced to overflow to [sqlite3_malloc()]. The 5124** returned value includes allocations that overflowed because they 5125** where too large (they were larger than the "sz" parameter to 5126** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 5127** no space was left in the page cache.</dd> 5128** 5129** <dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 5130** <dd>This parameter records the largest memory allocation request 5131** handed to [pagecache memory allocator]. Only the value returned in the 5132** *pHighwater parameter to [sqlite3_status()] is of interest. 5133** The value written into the *pCurrent parameter is undefined.</dd> 5134** 5135** <dt>SQLITE_STATUS_SCRATCH_USED</dt> 5136** <dd>This parameter returns the number of allocations used out of the 5137** [scratch memory allocator] configured using 5138** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5139** in bytes. Since a single thread may only have one scratch allocation 5140** outstanding at time, this parameter also reports the number of threads 5141** using scratch memory at the same time.</dd> 5142** 5143** <dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5144** <dd>This parameter returns the number of bytes of scratch memory 5145** allocation which could not be statisfied by the [SQLITE_CONFIG_SCRATCH] 5146** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5147** returned include overflows because the requested allocation was too 5148** larger (that is, because the requested allocation was larger than the 5149** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5150** slots were available. 5151** </dd> 5152** 5153** <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5154** <dd>This parameter records the largest memory allocation request 5155** handed to [scratch memory allocator]. Only the value returned in the 5156** *pHighwater parameter to [sqlite3_status()] is of interest. 5157** The value written into the *pCurrent parameter is undefined.</dd> 5158** 5159** <dt>SQLITE_STATUS_PARSER_STACK</dt> 5160** <dd>This parameter records the deepest parser stack. It is only 5161** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd> 5162** </dl> 5163** 5164** New status parameters may be added from time to time. 5165*/ 5166#define SQLITE_STATUS_MEMORY_USED 0 5167#define SQLITE_STATUS_PAGECACHE_USED 1 5168#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5169#define SQLITE_STATUS_SCRATCH_USED 3 5170#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5171#define SQLITE_STATUS_MALLOC_SIZE 5 5172#define SQLITE_STATUS_PARSER_STACK 6 5173#define SQLITE_STATUS_PAGECACHE_SIZE 7 5174#define SQLITE_STATUS_SCRATCH_SIZE 8 5175 5176/* 5177** CAPI3REF: Database Connection Status {H17500} <S60200> 5178** EXPERIMENTAL 5179** 5180** This interface is used to retrieve runtime status information 5181** about a single [database connection]. The first argument is the 5182** database connection object to be interrogated. The second argument 5183** is the parameter to interrogate. Currently, the only allowed value 5184** for the second parameter is [SQLITE_DBSTATUS_LOOKASIDE_USED]. 5185** Additional options will likely appear in future releases of SQLite. 5186** 5187** The current value of the requested parameter is written into *pCur 5188** and the highest instantaneous value is written into *pHiwtr. If 5189** the resetFlg is true, then the highest instantaneous value is 5190** reset back down to the current value. 5191** 5192** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5193*/ 5194SQLITE_EXPERIMENTAL int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5195 5196/* 5197** CAPI3REF: Status Parameters for database connections {H17520} <H17500> 5198** EXPERIMENTAL 5199** 5200** These constants are the available integer "verbs" that can be passed as 5201** the second argument to the [sqlite3_db_status()] interface. 5202** 5203** New verbs may be added in future releases of SQLite. Existing verbs 5204** might be discontinued. Applications should check the return code from 5205** [sqlite3_db_status()] to make sure that the call worked. 5206** The [sqlite3_db_status()] interface will return a non-zero error code 5207** if a discontinued or unsupported verb is invoked. 5208** 5209** <dl> 5210** <dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5211** <dd>This parameter returns the number of lookaside memory slots currently 5212** checked out.</dd> 5213** </dl> 5214*/ 5215#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 5216 5217 5218/* 5219** CAPI3REF: Prepared Statement Status {H17550} <S60200> 5220** EXPERIMENTAL 5221** 5222** Each prepared statement maintains various 5223** [SQLITE_STMTSTATUS_SORT | counters] that measure the number 5224** of times it has performed specific operations. These counters can 5225** be used to monitor the performance characteristics of the prepared 5226** statements. For example, if the number of table steps greatly exceeds 5227** the number of table searches or result rows, that would tend to indicate 5228** that the prepared statement is using a full table scan rather than 5229** an index. 5230** 5231** This interface is used to retrieve and reset counter values from 5232** a [prepared statement]. The first argument is the prepared statement 5233** object to be interrogated. The second argument 5234** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter] 5235** to be interrogated. 5236** The current value of the requested counter is returned. 5237** If the resetFlg is true, then the counter is reset to zero after this 5238** interface call returns. 5239** 5240** See also: [sqlite3_status()] and [sqlite3_db_status()]. 5241*/ 5242SQLITE_EXPERIMENTAL int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 5243 5244/* 5245** CAPI3REF: Status Parameters for prepared statements {H17570} <H17550> 5246** EXPERIMENTAL 5247** 5248** These preprocessor macros define integer codes that name counter 5249** values associated with the [sqlite3_stmt_status()] interface. 5250** The meanings of the various counters are as follows: 5251** 5252** <dl> 5253** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 5254** <dd>This is the number of times that SQLite has stepped forward in 5255** a table as part of a full table scan. Large numbers for this counter 5256** may indicate opportunities for performance improvement through 5257** careful use of indices.</dd> 5258** 5259** <dt>SQLITE_STMTSTATUS_SORT</dt> 5260** <dd>This is the number of sort operations that have occurred. 5261** A non-zero value in this counter may indicate an opportunity to 5262** improvement performance through careful use of indices.</dd> 5263** 5264** </dl> 5265*/ 5266#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 5267#define SQLITE_STMTSTATUS_SORT 2 5268 5269/* 5270** CAPI3REF: Custom Page Cache Object 5271** EXPERIMENTAL 5272** 5273** The sqlite3_pcache type is opaque. It is implemented by 5274** the pluggable module. The SQLite core has no knowledge of 5275** its size or internal structure and never deals with the 5276** sqlite3_pcache object except by holding and passing pointers 5277** to the object. 5278** 5279** See [sqlite3_pcache_methods] for additional information. 5280*/ 5281typedef struct sqlite3_pcache sqlite3_pcache; 5282 5283/* 5284** CAPI3REF: Application Defined Page Cache. 5285** KEYWORDS: {page cache} 5286** EXPERIMENTAL 5287** 5288** The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can 5289** register an alternative page cache implementation by passing in an 5290** instance of the sqlite3_pcache_methods structure. The majority of the 5291** heap memory used by SQLite is used by the page cache to cache data read 5292** from, or ready to be written to, the database file. By implementing a 5293** custom page cache using this API, an application can control more 5294** precisely the amount of memory consumed by SQLite, the way in which 5295** that memory is allocated and released, and the policies used to 5296** determine exactly which parts of a database file are cached and for 5297** how long. 5298** 5299** The contents of the sqlite3_pcache_methods structure are copied to an 5300** internal buffer by SQLite within the call to [sqlite3_config]. Hence 5301** the application may discard the parameter after the call to 5302** [sqlite3_config()] returns. 5303** 5304** The xInit() method is called once for each call to [sqlite3_initialize()] 5305** (usually only once during the lifetime of the process). It is passed 5306** a copy of the sqlite3_pcache_methods.pArg value. It can be used to set 5307** up global structures and mutexes required by the custom page cache 5308** implementation. 5309** 5310** The xShutdown() method is called from within [sqlite3_shutdown()], 5311** if the application invokes this API. It can be used to clean up 5312** any outstanding resources before process shutdown, if required. 5313** 5314** SQLite holds a [SQLITE_MUTEX_RECURSIVE] mutex when it invokes 5315** the xInit method, so the xInit method need not be threadsafe. The 5316** xShutdown method is only called from [sqlite3_shutdown()] so it does 5317** not need to be threadsafe either. All other methods must be threadsafe 5318** in multithreaded applications. 5319** 5320** SQLite will never invoke xInit() more than once without an intervening 5321** call to xShutdown(). 5322** 5323** The xCreate() method is used to construct a new cache instance. SQLite 5324** will typically create one cache instance for each open database file, 5325** though this is not guaranteed. The 5326** first parameter, szPage, is the size in bytes of the pages that must 5327** be allocated by the cache. szPage will not be a power of two. szPage 5328** will the page size of the database file that is to be cached plus an 5329** increment (here called "R") of about 100 or 200. SQLite will use the 5330** extra R bytes on each page to store metadata about the underlying 5331** database page on disk. The value of R depends 5332** on the SQLite version, the target platform, and how SQLite was compiled. 5333** R is constant for a particular build of SQLite. The second argument to 5334** xCreate(), bPurgeable, is true if the cache being created will 5335** be used to cache database pages of a file stored on disk, or 5336** false if it is used for an in-memory database. The cache implementation 5337** does not have to do anything special based with the value of bPurgeable; 5338** it is purely advisory. On a cache where bPurgeable is false, SQLite will 5339** never invoke xUnpin() except to deliberately delete a page. 5340** In other words, a cache created with bPurgeable set to false will 5341** never contain any unpinned pages. 5342** 5343** The xCachesize() method may be called at any time by SQLite to set the 5344** suggested maximum cache-size (number of pages stored by) the cache 5345** instance passed as the first argument. This is the value configured using 5346** the SQLite "[PRAGMA cache_size]" command. As with the bPurgeable parameter, 5347** the implementation is not required to do anything with this 5348** value; it is advisory only. 5349** 5350** The xPagecount() method should return the number of pages currently 5351** stored in the cache. 5352** 5353** The xFetch() method is used to fetch a page and return a pointer to it. 5354** A 'page', in this context, is a buffer of szPage bytes aligned at an 5355** 8-byte boundary. The page to be fetched is determined by the key. The 5356** mimimum key value is 1. After it has been retrieved using xFetch, the page 5357** is considered to be "pinned". 5358** 5359** If the requested page is already in the page cache, then the page cache 5360** implementation must return a pointer to the page buffer with its content 5361** intact. If the requested page is not already in the cache, then the 5362** behavior of the cache implementation is determined by the value of the 5363** createFlag parameter passed to xFetch, according to the following table: 5364** 5365** <table border=1 width=85% align=center> 5366** <tr><th> createFlag <th> Behaviour when page is not already in cache 5367** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 5368** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 5369** Otherwise return NULL. 5370** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 5371** NULL if allocating a new page is effectively impossible. 5372** </table> 5373** 5374** SQLite will normally invoke xFetch() with a createFlag of 0 or 1. If 5375** a call to xFetch() with createFlag==1 returns NULL, then SQLite will 5376** attempt to unpin one or more cache pages by spilling the content of 5377** pinned pages to disk and synching the operating system disk cache. After 5378** attempting to unpin pages, the xFetch() method will be invoked again with 5379** a createFlag of 2. 5380** 5381** xUnpin() is called by SQLite with a pointer to a currently pinned page 5382** as its second argument. If the third parameter, discard, is non-zero, 5383** then the page should be evicted from the cache. In this case SQLite 5384** assumes that the next time the page is retrieved from the cache using 5385** the xFetch() method, it will be zeroed. If the discard parameter is 5386** zero, then the page is considered to be unpinned. The cache implementation 5387** may choose to evict unpinned pages at any time. 5388** 5389** The cache is not required to perform any reference counting. A single 5390** call to xUnpin() unpins the page regardless of the number of prior calls 5391** to xFetch(). 5392** 5393** The xRekey() method is used to change the key value associated with the 5394** page passed as the second argument from oldKey to newKey. If the cache 5395** previously contains an entry associated with newKey, it should be 5396** discarded. Any prior cache entry associated with newKey is guaranteed not 5397** to be pinned. 5398** 5399** When SQLite calls the xTruncate() method, the cache must discard all 5400** existing cache entries with page numbers (keys) greater than or equal 5401** to the value of the iLimit parameter passed to xTruncate(). If any 5402** of these pages are pinned, they are implicitly unpinned, meaning that 5403** they can be safely discarded. 5404** 5405** The xDestroy() method is used to delete a cache allocated by xCreate(). 5406** All resources associated with the specified cache should be freed. After 5407** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 5408** handle invalid, and will not use it with any other sqlite3_pcache_methods 5409** functions. 5410*/ 5411typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 5412struct sqlite3_pcache_methods { 5413 void *pArg; 5414 int (*xInit)(void*); 5415 void (*xShutdown)(void*); 5416 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 5417 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 5418 int (*xPagecount)(sqlite3_pcache*); 5419 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 5420 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 5421 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 5422 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 5423 void (*xDestroy)(sqlite3_pcache*); 5424}; 5425 5426/* 5427** CAPI3REF: Online Backup Object 5428** EXPERIMENTAL 5429** 5430** The sqlite3_backup object records state information about an ongoing 5431** online backup operation. The sqlite3_backup object is created by 5432** a call to [sqlite3_backup_init()] and is destroyed by a call to 5433** [sqlite3_backup_finish()]. 5434** 5435** See Also: [Using the SQLite Online Backup API] 5436*/ 5437typedef struct sqlite3_backup sqlite3_backup; 5438 5439/* 5440** CAPI3REF: Online Backup API. 5441** EXPERIMENTAL 5442** 5443** This API is used to overwrite the contents of one database with that 5444** of another. It is useful either for creating backups of databases or 5445** for copying in-memory databases to or from persistent files. 5446** 5447** See Also: [Using the SQLite Online Backup API] 5448** 5449** Exclusive access is required to the destination database for the 5450** duration of the operation. However the source database is only 5451** read-locked while it is actually being read, it is not locked 5452** continuously for the entire operation. Thus, the backup may be 5453** performed on a live database without preventing other users from 5454** writing to the database for an extended period of time. 5455** 5456** To perform a backup operation: 5457** <ol> 5458** <li><b>sqlite3_backup_init()</b> is called once to initialize the 5459** backup, 5460** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 5461** the data between the two databases, and finally 5462** <li><b>sqlite3_backup_finish()</b> is called to release all resources 5463** associated with the backup operation. 5464** </ol> 5465** There should be exactly one call to sqlite3_backup_finish() for each 5466** successful call to sqlite3_backup_init(). 5467** 5468** <b>sqlite3_backup_init()</b> 5469** 5470** The first two arguments passed to [sqlite3_backup_init()] are the database 5471** handle associated with the destination database and the database name 5472** used to attach the destination database to the handle. The database name 5473** is "main" for the main database, "temp" for the temporary database, or 5474** the name specified as part of the [ATTACH] statement if the destination is 5475** an attached database. The third and fourth arguments passed to 5476** sqlite3_backup_init() identify the [database connection] 5477** and database name used 5478** to access the source database. The values passed for the source and 5479** destination [database connection] parameters must not be the same. 5480** 5481** If an error occurs within sqlite3_backup_init(), then NULL is returned 5482** and an error code and error message written into the [database connection] 5483** passed as the first argument. They may be retrieved using the 5484** [sqlite3_errcode()], [sqlite3_errmsg()], and [sqlite3_errmsg16()] functions. 5485** Otherwise, if successful, a pointer to an [sqlite3_backup] object is 5486** returned. This pointer may be used with the sqlite3_backup_step() and 5487** sqlite3_backup_finish() functions to perform the specified backup 5488** operation. 5489** 5490** <b>sqlite3_backup_step()</b> 5491** 5492** Function [sqlite3_backup_step()] is used to copy up to nPage pages between 5493** the source and destination databases, where nPage is the value of the 5494** second parameter passed to sqlite3_backup_step(). If nPage is a negative 5495** value, all remaining source pages are copied. If the required pages are 5496** succesfully copied, but there are still more pages to copy before the 5497** backup is complete, it returns [SQLITE_OK]. If no error occured and there 5498** are no more pages to copy, then [SQLITE_DONE] is returned. If an error 5499** occurs, then an SQLite error code is returned. As well as [SQLITE_OK] and 5500** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 5501** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 5502** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 5503** 5504** As well as the case where the destination database file was opened for 5505** read-only access, sqlite3_backup_step() may return [SQLITE_READONLY] if 5506** the destination is an in-memory database with a different page size 5507** from the source database. 5508** 5509** If sqlite3_backup_step() cannot obtain a required file-system lock, then 5510** the [sqlite3_busy_handler | busy-handler function] 5511** is invoked (if one is specified). If the 5512** busy-handler returns non-zero before the lock is available, then 5513** [SQLITE_BUSY] is returned to the caller. In this case the call to 5514** sqlite3_backup_step() can be retried later. If the source 5515** [database connection] 5516** is being used to write to the source database when sqlite3_backup_step() 5517** is called, then [SQLITE_LOCKED] is returned immediately. Again, in this 5518** case the call to sqlite3_backup_step() can be retried later on. If 5519** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 5520** [SQLITE_READONLY] is returned, then 5521** there is no point in retrying the call to sqlite3_backup_step(). These 5522** errors are considered fatal. At this point the application must accept 5523** that the backup operation has failed and pass the backup operation handle 5524** to the sqlite3_backup_finish() to release associated resources. 5525** 5526** Following the first call to sqlite3_backup_step(), an exclusive lock is 5527** obtained on the destination file. It is not released until either 5528** sqlite3_backup_finish() is called or the backup operation is complete 5529** and sqlite3_backup_step() returns [SQLITE_DONE]. Additionally, each time 5530** a call to sqlite3_backup_step() is made a [shared lock] is obtained on 5531** the source database file. This lock is released before the 5532** sqlite3_backup_step() call returns. Because the source database is not 5533** locked between calls to sqlite3_backup_step(), it may be modified mid-way 5534** through the backup procedure. If the source database is modified by an 5535** external process or via a database connection other than the one being 5536** used by the backup operation, then the backup will be transparently 5537** restarted by the next call to sqlite3_backup_step(). If the source 5538** database is modified by the using the same database connection as is used 5539** by the backup operation, then the backup database is transparently 5540** updated at the same time. 5541** 5542** <b>sqlite3_backup_finish()</b> 5543** 5544** Once sqlite3_backup_step() has returned [SQLITE_DONE], or when the 5545** application wishes to abandon the backup operation, the [sqlite3_backup] 5546** object should be passed to sqlite3_backup_finish(). This releases all 5547** resources associated with the backup operation. If sqlite3_backup_step() 5548** has not yet returned [SQLITE_DONE], then any active write-transaction on the 5549** destination database is rolled back. The [sqlite3_backup] object is invalid 5550** and may not be used following a call to sqlite3_backup_finish(). 5551** 5552** The value returned by sqlite3_backup_finish is [SQLITE_OK] if no error 5553** occurred, regardless or whether or not sqlite3_backup_step() was called 5554** a sufficient number of times to complete the backup operation. Or, if 5555** an out-of-memory condition or IO error occured during a call to 5556** sqlite3_backup_step() then [SQLITE_NOMEM] or an 5557** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] error code 5558** is returned. In this case the error code and an error message are 5559** written to the destination [database connection]. 5560** 5561** A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() is 5562** not a permanent error and does not affect the return value of 5563** sqlite3_backup_finish(). 5564** 5565** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b> 5566** 5567** Each call to sqlite3_backup_step() sets two values stored internally 5568** by an [sqlite3_backup] object. The number of pages still to be backed 5569** up, which may be queried by sqlite3_backup_remaining(), and the total 5570** number of pages in the source database file, which may be queried by 5571** sqlite3_backup_pagecount(). 5572** 5573** The values returned by these functions are only updated by 5574** sqlite3_backup_step(). If the source database is modified during a backup 5575** operation, then the values are not updated to account for any extra 5576** pages that need to be updated or the size of the source database file 5577** changing. 5578** 5579** <b>Concurrent Usage of Database Handles</b> 5580** 5581** The source [database connection] may be used by the application for other 5582** purposes while a backup operation is underway or being initialized. 5583** If SQLite is compiled and configured to support threadsafe database 5584** connections, then the source database connection may be used concurrently 5585** from within other threads. 5586** 5587** However, the application must guarantee that the destination database 5588** connection handle is not passed to any other API (by any thread) after 5589** sqlite3_backup_init() is called and before the corresponding call to 5590** sqlite3_backup_finish(). Unfortunately SQLite does not currently check 5591** for this, if the application does use the destination [database connection] 5592** for some other purpose during a backup operation, things may appear to 5593** work correctly but in fact be subtly malfunctioning. Use of the 5594** destination database connection while a backup is in progress might 5595** also cause a mutex deadlock. 5596** 5597** Furthermore, if running in [shared cache mode], the application must 5598** guarantee that the shared cache used by the destination database 5599** is not accessed while the backup is running. In practice this means 5600** that the application must guarantee that the file-system file being 5601** backed up to is not accessed by any connection within the process, 5602** not just the specific connection that was passed to sqlite3_backup_init(). 5603** 5604** The [sqlite3_backup] object itself is partially threadsafe. Multiple 5605** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 5606** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 5607** APIs are not strictly speaking threadsafe. If they are invoked at the 5608** same time as another thread is invoking sqlite3_backup_step() it is 5609** possible that they return invalid values. 5610*/ 5611sqlite3_backup *sqlite3_backup_init( 5612 sqlite3 *pDest, /* Destination database handle */ 5613 const char *zDestName, /* Destination database name */ 5614 sqlite3 *pSource, /* Source database handle */ 5615 const char *zSourceName /* Source database name */ 5616); 5617int sqlite3_backup_step(sqlite3_backup *p, int nPage); 5618int sqlite3_backup_finish(sqlite3_backup *p); 5619int sqlite3_backup_remaining(sqlite3_backup *p); 5620int sqlite3_backup_pagecount(sqlite3_backup *p); 5621 5622/* 5623** CAPI3REF: Unlock Notification 5624** EXPERIMENTAL 5625** 5626** When running in shared-cache mode, a database operation may fail with 5627** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 5628** individual tables within the shared-cache cannot be obtained. See 5629** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 5630** This API may be used to register a callback that SQLite will invoke 5631** when the connection currently holding the required lock relinquishes it. 5632** This API is only available if the library was compiled with the 5633** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 5634** 5635** See Also: [Using the SQLite Unlock Notification Feature]. 5636** 5637** Shared-cache locks are released when a database connection concludes 5638** its current transaction, either by committing it or rolling it back. 5639** 5640** When a connection (known as the blocked connection) fails to obtain a 5641** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 5642** identity of the database connection (the blocking connection) that 5643** has locked the required resource is stored internally. After an 5644** application receives an SQLITE_LOCKED error, it may call the 5645** sqlite3_unlock_notify() method with the blocked connection handle as 5646** the first argument to register for a callback that will be invoked 5647** when the blocking connections current transaction is concluded. The 5648** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 5649** call that concludes the blocking connections transaction. 5650** 5651** If sqlite3_unlock_notify() is called in a multi-threaded application, 5652** there is a chance that the blocking connection will have already 5653** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 5654** If this happens, then the specified callback is invoked immediately, 5655** from within the call to sqlite3_unlock_notify(). 5656** 5657** If the blocked connection is attempting to obtain a write-lock on a 5658** shared-cache table, and more than one other connection currently holds 5659** a read-lock on the same table, then SQLite arbitrarily selects one of 5660** the other connections to use as the blocking connection. 5661** 5662** There may be at most one unlock-notify callback registered by a 5663** blocked connection. If sqlite3_unlock_notify() is called when the 5664** blocked connection already has a registered unlock-notify callback, 5665** then the new callback replaces the old. If sqlite3_unlock_notify() is 5666** called with a NULL pointer as its second argument, then any existing 5667** unlock-notify callback is cancelled. The blocked connections 5668** unlock-notify callback may also be canceled by closing the blocked 5669** connection using [sqlite3_close()]. 5670** 5671** The unlock-notify callback is not reentrant. If an application invokes 5672** any sqlite3_xxx API functions from within an unlock-notify callback, a 5673** crash or deadlock may be the result. 5674** 5675** Unless deadlock is detected (see below), sqlite3_unlock_notify() always 5676** returns SQLITE_OK. 5677** 5678** <b>Callback Invocation Details</b> 5679** 5680** When an unlock-notify callback is registered, the application provides a 5681** single void* pointer that is passed to the callback when it is invoked. 5682** However, the signature of the callback function allows SQLite to pass 5683** it an array of void* context pointers. The first argument passed to 5684** an unlock-notify callback is a pointer to an array of void* pointers, 5685** and the second is the number of entries in the array. 5686** 5687** When a blocking connections transaction is concluded, there may be 5688** more than one blocked connection that has registered for an unlock-notify 5689** callback. If two or more such blocked connections have specified the 5690** same callback function, then instead of invoking the callback function 5691** multiple times, it is invoked once with the set of void* context pointers 5692** specified by the blocked connections bundled together into an array. 5693** This gives the application an opportunity to prioritize any actions 5694** related to the set of unblocked database connections. 5695** 5696** <b>Deadlock Detection</b> 5697** 5698** Assuming that after registering for an unlock-notify callback a 5699** database waits for the callback to be issued before taking any further 5700** action (a reasonable assumption), then using this API may cause the 5701** application to deadlock. For example, if connection X is waiting for 5702** connection Y's transaction to be concluded, and similarly connection 5703** Y is waiting on connection X's transaction, then neither connection 5704** will proceed and the system may remain deadlocked indefinitely. 5705** 5706** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 5707** detection. If a given call to sqlite3_unlock_notify() would put the 5708** system in a deadlocked state, then SQLITE_LOCKED is returned and no 5709** unlock-notify callback is registered. The system is said to be in 5710** a deadlocked state if connection A has registered for an unlock-notify 5711** callback on the conclusion of connection B's transaction, and connection 5712** B has itself registered for an unlock-notify callback when connection 5713** A's transaction is concluded. Indirect deadlock is also detected, so 5714** the system is also considered to be deadlocked if connection B has 5715** registered for an unlock-notify callback on the conclusion of connection 5716** C's transaction, where connection C is waiting on connection A. Any 5717** number of levels of indirection are allowed. 5718** 5719** <b>The "DROP TABLE" Exception</b> 5720** 5721** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 5722** always appropriate to call sqlite3_unlock_notify(). There is however, 5723** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 5724** SQLite checks if there are any currently executing SELECT statements 5725** that belong to the same connection. If there are, SQLITE_LOCKED is 5726** returned. In this case there is no "blocking connection", so invoking 5727** sqlite3_unlock_notify() results in the unlock-notify callback being 5728** invoked immediately. If the application then re-attempts the "DROP TABLE" 5729** or "DROP INDEX" query, an infinite loop might be the result. 5730** 5731** One way around this problem is to check the extended error code returned 5732** by an sqlite3_step() call. If there is a blocking connection, then the 5733** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 5734** the special "DROP TABLE/INDEX" case, the extended error code is just 5735** SQLITE_LOCKED. 5736*/ 5737int sqlite3_unlock_notify( 5738 sqlite3 *pBlocked, /* Waiting connection */ 5739 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 5740 void *pNotifyArg /* Argument to pass to xNotify */ 5741); 5742 5743 5744/* 5745** CAPI3REF: String Comparison 5746** EXPERIMENTAL 5747** 5748** The [sqlite3_strnicmp()] API allows applications and extensions to 5749** compare the contents of two buffers containing UTF-8 strings in a 5750** case-indendent fashion, using the same definition of case independence 5751** that SQLite uses internally when comparing identifiers. 5752*/ 5753int sqlite3_strnicmp(const char *, const char *, int); 5754 5755/* 5756** Undo the hack that converts floating point types to integer for 5757** builds on processors without floating point support. 5758*/ 5759#ifdef SQLITE_OMIT_FLOATING_POINT 5760# undef double 5761#endif 5762 5763#ifdef __cplusplus 5764} /* End of the 'extern "C"' block */ 5765#endif 5766#endif 5767