1/* 2** 2001 September 15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are suppose to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef _SQLITE3_H_ 34#define _SQLITE3_H_ 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Add the ability to override 'extern' 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51 52/* 53** These no-op macros are used in front of interfaces to mark those 54** interfaces as either deprecated or experimental. New applications 55** should not use deprecated interfaces - they are support for backwards 56** compatibility only. Application writers should be aware that 57** experimental interfaces are subject to change in point releases. 58** 59** These macros used to resolve to various kinds of compiler magic that 60** would generate warning messages when they were used. But that 61** compiler magic ended up generating such a flurry of bug reports 62** that we have taken it all out and gone back to using simple 63** noop macros. 64*/ 65#define SQLITE_DEPRECATED 66#define SQLITE_EXPERIMENTAL 67 68/* 69** Ensure these symbols were not defined by some previous header file. 70*/ 71#ifdef SQLITE_VERSION 72# undef SQLITE_VERSION 73#endif 74#ifdef SQLITE_VERSION_NUMBER 75# undef SQLITE_VERSION_NUMBER 76#endif 77 78/* 79** CAPI3REF: Compile-Time Library Version Numbers 80** 81** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 82** evaluates to a string literal that is the SQLite version in the 83** format "X.Y.Z" where X is the major version number (always 3 for 84** SQLite3) and Y is the minor version number and Z is the release number.)^ 85** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 86** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 87** numbers used in [SQLITE_VERSION].)^ 88** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 89** be larger than the release from which it is derived. Either Y will 90** be held constant and Z will be incremented or else Y will be incremented 91** and Z will be reset to zero. 92** 93** Since version 3.6.18, SQLite source code has been stored in the 94** <a href="http://www.fossil-scm.org/">Fossil configuration management 95** system</a>. ^The SQLITE_SOURCE_ID macro evalutes to 96** a string which identifies a particular check-in of SQLite 97** within its configuration management system. ^The SQLITE_SOURCE_ID 98** string contains the date and time of the check-in (UTC) and an SHA1 99** hash of the entire source tree. 100** 101** See also: [sqlite3_libversion()], 102** [sqlite3_libversion_number()], [sqlite3_sourceid()], 103** [sqlite_version()] and [sqlite_source_id()]. 104*/ 105#define SQLITE_VERSION "--VERS--" 106#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 107#define SQLITE_SOURCE_ID "--SOURCE-ID--" 108 109/* 110** CAPI3REF: Run-Time Library Version Numbers 111** KEYWORDS: sqlite3_version, sqlite3_sourceid 112** 113** These interfaces provide the same information as the [SQLITE_VERSION], 114** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 115** but are associated with the library instead of the header file. ^(Cautious 116** programmers might include assert() statements in their application to 117** verify that values returned by these interfaces match the macros in 118** the header, and thus insure that the application is 119** compiled with matching library and header files. 120** 121** <blockquote><pre> 122** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 123** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 124** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 125** </pre></blockquote>)^ 126** 127** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 128** macro. ^The sqlite3_libversion() function returns a pointer to the 129** to the sqlite3_version[] string constant. The sqlite3_libversion() 130** function is provided for use in DLLs since DLL users usually do not have 131** direct access to string constants within the DLL. ^The 132** sqlite3_libversion_number() function returns an integer equal to 133** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 134** a pointer to a string constant whose value is the same as the 135** [SQLITE_SOURCE_ID] C preprocessor macro. 136** 137** See also: [sqlite_version()] and [sqlite_source_id()]. 138*/ 139SQLITE_EXTERN const char sqlite3_version[]; 140const char *sqlite3_libversion(void); 141const char *sqlite3_sourceid(void); 142int sqlite3_libversion_number(void); 143 144/* 145** CAPI3REF: Run-Time Library Compilation Options Diagnostics 146** 147** ^The sqlite3_compileoption_used() function returns 0 or 1 148** indicating whether the specified option was defined at 149** compile time. ^The SQLITE_ prefix may be omitted from the 150** option name passed to sqlite3_compileoption_used(). 151** 152** ^The sqlite3_compileoption_get() function allows interating 153** over the list of options that were defined at compile time by 154** returning the N-th compile time option string. ^If N is out of range, 155** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 156** prefix is omitted from any strings returned by 157** sqlite3_compileoption_get(). 158** 159** ^Support for the diagnostic functions sqlite3_compileoption_used() 160** and sqlite3_compileoption_get() may be omitted by specifing the 161** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 162** 163** See also: SQL functions [sqlite_compileoption_used()] and 164** [sqlite_compileoption_get()] and the [compile_options pragma]. 165*/ 166#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 167int sqlite3_compileoption_used(const char *zOptName); 168const char *sqlite3_compileoption_get(int N); 169#endif 170 171/* 172** CAPI3REF: Test To See If The Library Is Threadsafe 173** 174** ^The sqlite3_threadsafe() function returns zero if and only if 175** SQLite was compiled mutexing code omitted due to the 176** [SQLITE_THREADSAFE] compile-time option being set to 0. 177** 178** SQLite can be compiled with or without mutexes. When 179** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 180** are enabled and SQLite is threadsafe. When the 181** [SQLITE_THREADSAFE] macro is 0, 182** the mutexes are omitted. Without the mutexes, it is not safe 183** to use SQLite concurrently from more than one thread. 184** 185** Enabling mutexes incurs a measurable performance penalty. 186** So if speed is of utmost importance, it makes sense to disable 187** the mutexes. But for maximum safety, mutexes should be enabled. 188** ^The default behavior is for mutexes to be enabled. 189** 190** This interface can be used by an application to make sure that the 191** version of SQLite that it is linking against was compiled with 192** the desired setting of the [SQLITE_THREADSAFE] macro. 193** 194** This interface only reports on the compile-time mutex setting 195** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 196** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 197** can be fully or partially disabled using a call to [sqlite3_config()] 198** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 199** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the 200** sqlite3_threadsafe() function shows only the compile-time setting of 201** thread safety, not any run-time changes to that setting made by 202** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 203** is unchanged by calls to sqlite3_config().)^ 204** 205** See the [threading mode] documentation for additional information. 206*/ 207int sqlite3_threadsafe(void); 208 209/* 210** CAPI3REF: Database Connection Handle 211** KEYWORDS: {database connection} {database connections} 212** 213** Each open SQLite database is represented by a pointer to an instance of 214** the opaque structure named "sqlite3". It is useful to think of an sqlite3 215** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 216** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 217** is its destructor. There are many other interfaces (such as 218** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 219** [sqlite3_busy_timeout()] to name but three) that are methods on an 220** sqlite3 object. 221*/ 222typedef struct sqlite3 sqlite3; 223 224/* 225** CAPI3REF: 64-Bit Integer Types 226** KEYWORDS: sqlite_int64 sqlite_uint64 227** 228** Because there is no cross-platform way to specify 64-bit integer types 229** SQLite includes typedefs for 64-bit signed and unsigned integers. 230** 231** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 232** The sqlite_int64 and sqlite_uint64 types are supported for backwards 233** compatibility only. 234** 235** ^The sqlite3_int64 and sqlite_int64 types can store integer values 236** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 237** sqlite3_uint64 and sqlite_uint64 types can store integer values 238** between 0 and +18446744073709551615 inclusive. 239*/ 240#ifdef SQLITE_INT64_TYPE 241 typedef SQLITE_INT64_TYPE sqlite_int64; 242 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 243#elif defined(_MSC_VER) || defined(__BORLANDC__) 244 typedef __int64 sqlite_int64; 245 typedef unsigned __int64 sqlite_uint64; 246#else 247 typedef long long int sqlite_int64; 248 typedef unsigned long long int sqlite_uint64; 249#endif 250typedef sqlite_int64 sqlite3_int64; 251typedef sqlite_uint64 sqlite3_uint64; 252 253/* 254** If compiling for a processor that lacks floating point support, 255** substitute integer for floating-point. 256*/ 257#ifdef SQLITE_OMIT_FLOATING_POINT 258# define double sqlite3_int64 259#endif 260 261/* 262** CAPI3REF: Closing A Database Connection 263** 264** ^The sqlite3_close() routine is the destructor for the [sqlite3] object. 265** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is 266** successfullly destroyed and all associated resources are deallocated. 267** 268** Applications must [sqlite3_finalize | finalize] all [prepared statements] 269** and [sqlite3_blob_close | close] all [BLOB handles] associated with 270** the [sqlite3] object prior to attempting to close the object. ^If 271** sqlite3_close() is called on a [database connection] that still has 272** outstanding [prepared statements] or [BLOB handles], then it returns 273** SQLITE_BUSY. 274** 275** ^If [sqlite3_close()] is invoked while a transaction is open, 276** the transaction is automatically rolled back. 277** 278** The C parameter to [sqlite3_close(C)] must be either a NULL 279** pointer or an [sqlite3] object pointer obtained 280** from [sqlite3_open()], [sqlite3_open16()], or 281** [sqlite3_open_v2()], and not previously closed. 282** ^Calling sqlite3_close() with a NULL pointer argument is a 283** harmless no-op. 284*/ 285int sqlite3_close(sqlite3 *); 286 287/* 288** The type for a callback function. 289** This is legacy and deprecated. It is included for historical 290** compatibility and is not documented. 291*/ 292typedef int (*sqlite3_callback)(void*,int,char**, char**); 293 294/* 295** CAPI3REF: One-Step Query Execution Interface 296** 297** The sqlite3_exec() interface is a convenience wrapper around 298** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 299** that allows an application to run multiple statements of SQL 300** without having to use a lot of C code. 301** 302** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 303** semicolon-separate SQL statements passed into its 2nd argument, 304** in the context of the [database connection] passed in as its 1st 305** argument. ^If the callback function of the 3rd argument to 306** sqlite3_exec() is not NULL, then it is invoked for each result row 307** coming out of the evaluated SQL statements. ^The 4th argument to 308** to sqlite3_exec() is relayed through to the 1st argument of each 309** callback invocation. ^If the callback pointer to sqlite3_exec() 310** is NULL, then no callback is ever invoked and result rows are 311** ignored. 312** 313** ^If an error occurs while evaluating the SQL statements passed into 314** sqlite3_exec(), then execution of the current statement stops and 315** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 316** is not NULL then any error message is written into memory obtained 317** from [sqlite3_malloc()] and passed back through the 5th parameter. 318** To avoid memory leaks, the application should invoke [sqlite3_free()] 319** on error message strings returned through the 5th parameter of 320** of sqlite3_exec() after the error message string is no longer needed. 321** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 322** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 323** NULL before returning. 324** 325** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 326** routine returns SQLITE_ABORT without invoking the callback again and 327** without running any subsequent SQL statements. 328** 329** ^The 2nd argument to the sqlite3_exec() callback function is the 330** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 331** callback is an array of pointers to strings obtained as if from 332** [sqlite3_column_text()], one for each column. ^If an element of a 333** result row is NULL then the corresponding string pointer for the 334** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 335** sqlite3_exec() callback is an array of pointers to strings where each 336** entry represents the name of corresponding result column as obtained 337** from [sqlite3_column_name()]. 338** 339** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 340** to an empty string, or a pointer that contains only whitespace and/or 341** SQL comments, then no SQL statements are evaluated and the database 342** is not changed. 343** 344** Restrictions: 345** 346** <ul> 347** <li> The application must insure that the 1st parameter to sqlite3_exec() 348** is a valid and open [database connection]. 349** <li> The application must not close [database connection] specified by 350** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 351** <li> The application must not modify the SQL statement text passed into 352** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 353** </ul> 354*/ 355int sqlite3_exec( 356 sqlite3*, /* An open database */ 357 const char *sql, /* SQL to be evaluated */ 358 int (*callback)(void*,int,char**,char**), /* Callback function */ 359 void *, /* 1st argument to callback */ 360 char **errmsg /* Error msg written here */ 361); 362 363/* 364** CAPI3REF: Result Codes 365** KEYWORDS: SQLITE_OK {error code} {error codes} 366** KEYWORDS: {result code} {result codes} 367** 368** Many SQLite functions return an integer result code from the set shown 369** here in order to indicates success or failure. 370** 371** New error codes may be added in future versions of SQLite. 372** 373** See also: [SQLITE_IOERR_READ | extended result codes] 374*/ 375#define SQLITE_OK 0 /* Successful result */ 376/* beginning-of-error-codes */ 377#define SQLITE_ERROR 1 /* SQL error or missing database */ 378#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 379#define SQLITE_PERM 3 /* Access permission denied */ 380#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 381#define SQLITE_BUSY 5 /* The database file is locked */ 382#define SQLITE_LOCKED 6 /* A table in the database is locked */ 383#define SQLITE_NOMEM 7 /* A malloc() failed */ 384#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 385#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 386#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 387#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 388#define SQLITE_NOTFOUND 12 /* NOT USED. Table or record not found */ 389#define SQLITE_FULL 13 /* Insertion failed because database is full */ 390#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 391#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 392#define SQLITE_EMPTY 16 /* Database is empty */ 393#define SQLITE_SCHEMA 17 /* The database schema changed */ 394#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 395#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 396#define SQLITE_MISMATCH 20 /* Data type mismatch */ 397#define SQLITE_MISUSE 21 /* Library used incorrectly */ 398#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 399#define SQLITE_AUTH 23 /* Authorization denied */ 400#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 401#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 402#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 403#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 404#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 405/* end-of-error-codes */ 406 407/* 408** CAPI3REF: Extended Result Codes 409** KEYWORDS: {extended error code} {extended error codes} 410** KEYWORDS: {extended result code} {extended result codes} 411** 412** In its default configuration, SQLite API routines return one of 26 integer 413** [SQLITE_OK | result codes]. However, experience has shown that many of 414** these result codes are too coarse-grained. They do not provide as 415** much information about problems as programmers might like. In an effort to 416** address this, newer versions of SQLite (version 3.3.8 and later) include 417** support for additional result codes that provide more detailed information 418** about errors. The extended result codes are enabled or disabled 419** on a per database connection basis using the 420** [sqlite3_extended_result_codes()] API. 421** 422** Some of the available extended result codes are listed here. 423** One may expect the number of extended result codes will be expand 424** over time. Software that uses extended result codes should expect 425** to see new result codes in future releases of SQLite. 426** 427** The SQLITE_OK result code will never be extended. It will always 428** be exactly zero. 429*/ 430#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 431#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 432#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 433#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 434#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 435#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 436#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 437#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 438#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 439#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 440#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 441#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 442#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 443#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 444#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 445#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 446#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 447#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 448#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 449#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 450#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 451#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 452#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 453 454/* 455** CAPI3REF: Flags For File Open Operations 456** 457** These bit values are intended for use in the 458** 3rd parameter to the [sqlite3_open_v2()] interface and 459** in the 4th parameter to the xOpen method of the 460** [sqlite3_vfs] object. 461*/ 462#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 463#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 464#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 465#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 466#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 467#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 468#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 469#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 470#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 471#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 472#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 473#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 474#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 475#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 476#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 477#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 478#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 479 480/* 481** CAPI3REF: Device Characteristics 482** 483** The xDeviceCapabilities method of the [sqlite3_io_methods] 484** object returns an integer which is a vector of the these 485** bit values expressing I/O characteristics of the mass storage 486** device that holds the file that the [sqlite3_io_methods] 487** refers to. 488** 489** The SQLITE_IOCAP_ATOMIC property means that all writes of 490** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 491** mean that writes of blocks that are nnn bytes in size and 492** are aligned to an address which is an integer multiple of 493** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 494** that when data is appended to a file, the data is appended 495** first then the size of the file is extended, never the other 496** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 497** information is written to disk in the same order as calls 498** to xWrite(). 499*/ 500#define SQLITE_IOCAP_ATOMIC 0x00000001 501#define SQLITE_IOCAP_ATOMIC512 0x00000002 502#define SQLITE_IOCAP_ATOMIC1K 0x00000004 503#define SQLITE_IOCAP_ATOMIC2K 0x00000008 504#define SQLITE_IOCAP_ATOMIC4K 0x00000010 505#define SQLITE_IOCAP_ATOMIC8K 0x00000020 506#define SQLITE_IOCAP_ATOMIC16K 0x00000040 507#define SQLITE_IOCAP_ATOMIC32K 0x00000080 508#define SQLITE_IOCAP_ATOMIC64K 0x00000100 509#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 510#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 511#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 512 513/* 514** CAPI3REF: File Locking Levels 515** 516** SQLite uses one of these integer values as the second 517** argument to calls it makes to the xLock() and xUnlock() methods 518** of an [sqlite3_io_methods] object. 519*/ 520#define SQLITE_LOCK_NONE 0 521#define SQLITE_LOCK_SHARED 1 522#define SQLITE_LOCK_RESERVED 2 523#define SQLITE_LOCK_PENDING 3 524#define SQLITE_LOCK_EXCLUSIVE 4 525 526/* 527** CAPI3REF: Synchronization Type Flags 528** 529** When SQLite invokes the xSync() method of an 530** [sqlite3_io_methods] object it uses a combination of 531** these integer values as the second argument. 532** 533** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 534** sync operation only needs to flush data to mass storage. Inode 535** information need not be flushed. If the lower four bits of the flag 536** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 537** If the lower four bits equal SQLITE_SYNC_FULL, that means 538** to use Mac OS X style fullsync instead of fsync(). 539*/ 540#define SQLITE_SYNC_NORMAL 0x00002 541#define SQLITE_SYNC_FULL 0x00003 542#define SQLITE_SYNC_DATAONLY 0x00010 543 544/* 545** CAPI3REF: OS Interface Open File Handle 546** 547** An [sqlite3_file] object represents an open file in the 548** [sqlite3_vfs | OS interface layer]. Individual OS interface 549** implementations will 550** want to subclass this object by appending additional fields 551** for their own use. The pMethods entry is a pointer to an 552** [sqlite3_io_methods] object that defines methods for performing 553** I/O operations on the open file. 554*/ 555typedef struct sqlite3_file sqlite3_file; 556struct sqlite3_file { 557 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 558}; 559 560/* 561** CAPI3REF: OS Interface File Virtual Methods Object 562** 563** Every file opened by the [sqlite3_vfs] xOpen method populates an 564** [sqlite3_file] object (or, more commonly, a subclass of the 565** [sqlite3_file] object) with a pointer to an instance of this object. 566** This object defines the methods used to perform various operations 567** against the open file represented by the [sqlite3_file] object. 568** 569** If the xOpen method sets the sqlite3_file.pMethods element 570** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 571** may be invoked even if the xOpen reported that it failed. The 572** only way to prevent a call to xClose following a failed xOpen 573** is for the xOpen to set the sqlite3_file.pMethods element to NULL. 574** 575** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 576** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 577** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 578** flag may be ORed in to indicate that only the data of the file 579** and not its inode needs to be synced. 580** 581** The integer values to xLock() and xUnlock() are one of 582** <ul> 583** <li> [SQLITE_LOCK_NONE], 584** <li> [SQLITE_LOCK_SHARED], 585** <li> [SQLITE_LOCK_RESERVED], 586** <li> [SQLITE_LOCK_PENDING], or 587** <li> [SQLITE_LOCK_EXCLUSIVE]. 588** </ul> 589** xLock() increases the lock. xUnlock() decreases the lock. 590** The xCheckReservedLock() method checks whether any database connection, 591** either in this process or in some other process, is holding a RESERVED, 592** PENDING, or EXCLUSIVE lock on the file. It returns true 593** if such a lock exists and false otherwise. 594** 595** The xFileControl() method is a generic interface that allows custom 596** VFS implementations to directly control an open file using the 597** [sqlite3_file_control()] interface. The second "op" argument is an 598** integer opcode. The third argument is a generic pointer intended to 599** point to a structure that may contain arguments or space in which to 600** write return values. Potential uses for xFileControl() might be 601** functions to enable blocking locks with timeouts, to change the 602** locking strategy (for example to use dot-file locks), to inquire 603** about the status of a lock, or to break stale locks. The SQLite 604** core reserves all opcodes less than 100 for its own use. 605** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 606** Applications that define a custom xFileControl method should use opcodes 607** greater than 100 to avoid conflicts. 608** 609** The xSectorSize() method returns the sector size of the 610** device that underlies the file. The sector size is the 611** minimum write that can be performed without disturbing 612** other bytes in the file. The xDeviceCharacteristics() 613** method returns a bit vector describing behaviors of the 614** underlying device: 615** 616** <ul> 617** <li> [SQLITE_IOCAP_ATOMIC] 618** <li> [SQLITE_IOCAP_ATOMIC512] 619** <li> [SQLITE_IOCAP_ATOMIC1K] 620** <li> [SQLITE_IOCAP_ATOMIC2K] 621** <li> [SQLITE_IOCAP_ATOMIC4K] 622** <li> [SQLITE_IOCAP_ATOMIC8K] 623** <li> [SQLITE_IOCAP_ATOMIC16K] 624** <li> [SQLITE_IOCAP_ATOMIC32K] 625** <li> [SQLITE_IOCAP_ATOMIC64K] 626** <li> [SQLITE_IOCAP_SAFE_APPEND] 627** <li> [SQLITE_IOCAP_SEQUENTIAL] 628** </ul> 629** 630** The SQLITE_IOCAP_ATOMIC property means that all writes of 631** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 632** mean that writes of blocks that are nnn bytes in size and 633** are aligned to an address which is an integer multiple of 634** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 635** that when data is appended to a file, the data is appended 636** first then the size of the file is extended, never the other 637** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 638** information is written to disk in the same order as calls 639** to xWrite(). 640** 641** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 642** in the unread portions of the buffer with zeros. A VFS that 643** fails to zero-fill short reads might seem to work. However, 644** failure to zero-fill short reads will eventually lead to 645** database corruption. 646*/ 647typedef struct sqlite3_io_methods sqlite3_io_methods; 648struct sqlite3_io_methods { 649 int iVersion; 650 int (*xClose)(sqlite3_file*); 651 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 652 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 653 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 654 int (*xSync)(sqlite3_file*, int flags); 655 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 656 int (*xLock)(sqlite3_file*, int); 657 int (*xUnlock)(sqlite3_file*, int); 658 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 659 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 660 int (*xSectorSize)(sqlite3_file*); 661 int (*xDeviceCharacteristics)(sqlite3_file*); 662 /* Methods above are valid for version 1 */ 663 int (*xShmOpen)(sqlite3_file*); 664 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 665 int (*xShmMap)(sqlite3_file*, int iPage, int pgsz, int, void volatile**); 666 void (*xShmBarrier)(sqlite3_file*); 667 int (*xShmClose)(sqlite3_file*, int deleteFlag); 668 /* Methods above are valid for version 2 */ 669 /* Additional methods may be added in future releases */ 670}; 671 672/* 673** CAPI3REF: Standard File Control Opcodes 674** 675** These integer constants are opcodes for the xFileControl method 676** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 677** interface. 678** 679** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 680** opcode causes the xFileControl method to write the current state of 681** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 682** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 683** into an integer that the pArg argument points to. This capability 684** is used during testing and only needs to be supported when SQLITE_TEST 685** is defined. 686** 687** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 688** layer a hint of how large the database file will grow to be during the 689** current transaction. This hint is not guaranteed to be accurate but it 690** is often close. The underlying VFS might choose to preallocate database 691** file space based on this hint in order to help writes to the database 692** file run faster. 693*/ 694#define SQLITE_FCNTL_LOCKSTATE 1 695#define SQLITE_GET_LOCKPROXYFILE 2 696#define SQLITE_SET_LOCKPROXYFILE 3 697#define SQLITE_LAST_ERRNO 4 698#define SQLITE_FCNTL_SIZE_HINT 5 699 700/* 701** CAPI3REF: Mutex Handle 702** 703** The mutex module within SQLite defines [sqlite3_mutex] to be an 704** abstract type for a mutex object. The SQLite core never looks 705** at the internal representation of an [sqlite3_mutex]. It only 706** deals with pointers to the [sqlite3_mutex] object. 707** 708** Mutexes are created using [sqlite3_mutex_alloc()]. 709*/ 710typedef struct sqlite3_mutex sqlite3_mutex; 711 712/* 713** CAPI3REF: OS Interface Object 714** 715** An instance of the sqlite3_vfs object defines the interface between 716** the SQLite core and the underlying operating system. The "vfs" 717** in the name of the object stands for "virtual file system". 718** 719** The value of the iVersion field is initially 1 but may be larger in 720** future versions of SQLite. Additional fields may be appended to this 721** object when the iVersion value is increased. Note that the structure 722** of the sqlite3_vfs object changes in the transaction between 723** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 724** modified. 725** 726** The szOsFile field is the size of the subclassed [sqlite3_file] 727** structure used by this VFS. mxPathname is the maximum length of 728** a pathname in this VFS. 729** 730** Registered sqlite3_vfs objects are kept on a linked list formed by 731** the pNext pointer. The [sqlite3_vfs_register()] 732** and [sqlite3_vfs_unregister()] interfaces manage this list 733** in a thread-safe way. The [sqlite3_vfs_find()] interface 734** searches the list. Neither the application code nor the VFS 735** implementation should use the pNext pointer. 736** 737** The pNext field is the only field in the sqlite3_vfs 738** structure that SQLite will ever modify. SQLite will only access 739** or modify this field while holding a particular static mutex. 740** The application should never modify anything within the sqlite3_vfs 741** object once the object has been registered. 742** 743** The zName field holds the name of the VFS module. The name must 744** be unique across all VFS modules. 745** 746** SQLite will guarantee that the zFilename parameter to xOpen 747** is either a NULL pointer or string obtained 748** from xFullPathname(). SQLite further guarantees that 749** the string will be valid and unchanged until xClose() is 750** called. Because of the previous sentence, 751** the [sqlite3_file] can safely store a pointer to the 752** filename if it needs to remember the filename for some reason. 753** If the zFilename parameter is xOpen is a NULL pointer then xOpen 754** must invent its own temporary name for the file. Whenever the 755** xFilename parameter is NULL it will also be the case that the 756** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 757** 758** The flags argument to xOpen() includes all bits set in 759** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 760** or [sqlite3_open16()] is used, then flags includes at least 761** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 762** If xOpen() opens a file read-only then it sets *pOutFlags to 763** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 764** 765** SQLite will also add one of the following flags to the xOpen() 766** call, depending on the object being opened: 767** 768** <ul> 769** <li> [SQLITE_OPEN_MAIN_DB] 770** <li> [SQLITE_OPEN_MAIN_JOURNAL] 771** <li> [SQLITE_OPEN_TEMP_DB] 772** <li> [SQLITE_OPEN_TEMP_JOURNAL] 773** <li> [SQLITE_OPEN_TRANSIENT_DB] 774** <li> [SQLITE_OPEN_SUBJOURNAL] 775** <li> [SQLITE_OPEN_MASTER_JOURNAL] 776** </ul> 777** 778** The file I/O implementation can use the object type flags to 779** change the way it deals with files. For example, an application 780** that does not care about crash recovery or rollback might make 781** the open of a journal file a no-op. Writes to this journal would 782** also be no-ops, and any attempt to read the journal would return 783** SQLITE_IOERR. Or the implementation might recognize that a database 784** file will be doing page-aligned sector reads and writes in a random 785** order and set up its I/O subsystem accordingly. 786** 787** SQLite might also add one of the following flags to the xOpen method: 788** 789** <ul> 790** <li> [SQLITE_OPEN_DELETEONCLOSE] 791** <li> [SQLITE_OPEN_EXCLUSIVE] 792** </ul> 793** 794** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 795** deleted when it is closed. The [SQLITE_OPEN_DELETEONCLOSE] 796** will be set for TEMP databases, journals and for subjournals. 797** 798** The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 799** with the [SQLITE_OPEN_CREATE] flag, which are both directly 800** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 801** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 802** SQLITE_OPEN_CREATE, is used to indicate that file should always 803** be created, and that it is an error if it already exists. 804** It is <i>not</i> used to indicate the file should be opened 805** for exclusive access. 806** 807** At least szOsFile bytes of memory are allocated by SQLite 808** to hold the [sqlite3_file] structure passed as the third 809** argument to xOpen. The xOpen method does not have to 810** allocate the structure; it should just fill it in. Note that 811** the xOpen method must set the sqlite3_file.pMethods to either 812** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 813** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 814** element will be valid after xOpen returns regardless of the success 815** or failure of the xOpen call. 816** 817** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 818** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 819** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 820** to test whether a file is at least readable. The file can be a 821** directory. 822** 823** SQLite will always allocate at least mxPathname+1 bytes for the 824** output buffer xFullPathname. The exact size of the output buffer 825** is also passed as a parameter to both methods. If the output buffer 826** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 827** handled as a fatal error by SQLite, vfs implementations should endeavor 828** to prevent this by setting mxPathname to a sufficiently large value. 829** 830** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 831** interfaces are not strictly a part of the filesystem, but they are 832** included in the VFS structure for completeness. 833** The xRandomness() function attempts to return nBytes bytes 834** of good-quality randomness into zOut. The return value is 835** the actual number of bytes of randomness obtained. 836** The xSleep() method causes the calling thread to sleep for at 837** least the number of microseconds given. The xCurrentTime() 838** method returns a Julian Day Number for the current date and time as 839** a floating point value. 840** The xCurrentTimeInt64() method returns, as an integer, the Julian 841** Day Number multipled by 86400000 (the number of milliseconds in 842** a 24-hour day). 843** ^SQLite will use the xCurrentTimeInt64() method to get the current 844** date and time if that method is available (if iVersion is 2 or 845** greater and the function pointer is not NULL) and will fall back 846** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 847*/ 848typedef struct sqlite3_vfs sqlite3_vfs; 849struct sqlite3_vfs { 850 int iVersion; /* Structure version number (currently 2) */ 851 int szOsFile; /* Size of subclassed sqlite3_file */ 852 int mxPathname; /* Maximum file pathname length */ 853 sqlite3_vfs *pNext; /* Next registered VFS */ 854 const char *zName; /* Name of this virtual file system */ 855 void *pAppData; /* Pointer to application-specific data */ 856 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 857 int flags, int *pOutFlags); 858 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 859 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 860 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 861 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 862 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 863 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 864 void (*xDlClose)(sqlite3_vfs*, void*); 865 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 866 int (*xSleep)(sqlite3_vfs*, int microseconds); 867 int (*xCurrentTime)(sqlite3_vfs*, double*); 868 int (*xGetLastError)(sqlite3_vfs*, int, char *); 869 /* 870 ** The methods above are in version 1 of the sqlite_vfs object 871 ** definition. Those that follow are added in version 2 or later 872 */ 873 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 874 /* 875 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 876 ** New fields may be appended in figure versions. The iVersion 877 ** value will increment whenever this happens. 878 */ 879}; 880 881/* 882** CAPI3REF: Flags for the xAccess VFS method 883** 884** These integer constants can be used as the third parameter to 885** the xAccess method of an [sqlite3_vfs] object. They determine 886** what kind of permissions the xAccess method is looking for. 887** With SQLITE_ACCESS_EXISTS, the xAccess method 888** simply checks whether the file exists. 889** With SQLITE_ACCESS_READWRITE, the xAccess method 890** checks whether the file is both readable and writable. 891** With SQLITE_ACCESS_READ, the xAccess method 892** checks whether the file is readable. 893*/ 894#define SQLITE_ACCESS_EXISTS 0 895#define SQLITE_ACCESS_READWRITE 1 896#define SQLITE_ACCESS_READ 2 897 898/* 899** CAPI3REF: Flags for the xShmLock VFS method 900** 901** These integer constants define the various locking operations 902** allowed by the xShmLock method of [sqlite3_io_methods]. The 903** following are the only legal combinations of flags to the 904** xShmLock method: 905** 906** <ul> 907** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 908** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 909** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 910** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 911** </ul> 912** 913** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 914** was given no the corresponding lock. 915** 916** The xShmLock method can transition between unlocked and SHARED or 917** between unlocked and EXCLUSIVE. It cannot transition between SHARED 918** and EXCLUSIVE. 919*/ 920#define SQLITE_SHM_UNLOCK 1 921#define SQLITE_SHM_LOCK 2 922#define SQLITE_SHM_SHARED 4 923#define SQLITE_SHM_EXCLUSIVE 8 924 925/* 926** CAPI3REF: Maximum xShmLock index 927** 928** The xShmLock method on [sqlite3_io_methods] may use values 929** between 0 and this upper bound as its "offset" argument. 930** The SQLite core will never attempt to acquire or release a 931** lock outside of this range 932*/ 933#define SQLITE_SHM_NLOCK 8 934 935 936/* 937** CAPI3REF: Initialize The SQLite Library 938** 939** ^The sqlite3_initialize() routine initializes the 940** SQLite library. ^The sqlite3_shutdown() routine 941** deallocates any resources that were allocated by sqlite3_initialize(). 942** These routines are designed to aid in process initialization and 943** shutdown on embedded systems. Workstation applications using 944** SQLite normally do not need to invoke either of these routines. 945** 946** A call to sqlite3_initialize() is an "effective" call if it is 947** the first time sqlite3_initialize() is invoked during the lifetime of 948** the process, or if it is the first time sqlite3_initialize() is invoked 949** following a call to sqlite3_shutdown(). ^(Only an effective call 950** of sqlite3_initialize() does any initialization. All other calls 951** are harmless no-ops.)^ 952** 953** A call to sqlite3_shutdown() is an "effective" call if it is the first 954** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 955** an effective call to sqlite3_shutdown() does any deinitialization. 956** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 957** 958** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 959** is not. The sqlite3_shutdown() interface must only be called from a 960** single thread. All open [database connections] must be closed and all 961** other SQLite resources must be deallocated prior to invoking 962** sqlite3_shutdown(). 963** 964** Among other things, ^sqlite3_initialize() will invoke 965** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 966** will invoke sqlite3_os_end(). 967** 968** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 969** ^If for some reason, sqlite3_initialize() is unable to initialize 970** the library (perhaps it is unable to allocate a needed resource such 971** as a mutex) it returns an [error code] other than [SQLITE_OK]. 972** 973** ^The sqlite3_initialize() routine is called internally by many other 974** SQLite interfaces so that an application usually does not need to 975** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 976** calls sqlite3_initialize() so the SQLite library will be automatically 977** initialized when [sqlite3_open()] is called if it has not be initialized 978** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 979** compile-time option, then the automatic calls to sqlite3_initialize() 980** are omitted and the application must call sqlite3_initialize() directly 981** prior to using any other SQLite interface. For maximum portability, 982** it is recommended that applications always invoke sqlite3_initialize() 983** directly prior to using any other SQLite interface. Future releases 984** of SQLite may require this. In other words, the behavior exhibited 985** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 986** default behavior in some future release of SQLite. 987** 988** The sqlite3_os_init() routine does operating-system specific 989** initialization of the SQLite library. The sqlite3_os_end() 990** routine undoes the effect of sqlite3_os_init(). Typical tasks 991** performed by these routines include allocation or deallocation 992** of static resources, initialization of global variables, 993** setting up a default [sqlite3_vfs] module, or setting up 994** a default configuration using [sqlite3_config()]. 995** 996** The application should never invoke either sqlite3_os_init() 997** or sqlite3_os_end() directly. The application should only invoke 998** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 999** interface is called automatically by sqlite3_initialize() and 1000** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1001** implementations for sqlite3_os_init() and sqlite3_os_end() 1002** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1003** When [custom builds | built for other platforms] 1004** (using the [SQLITE_OS_OTHER=1] compile-time 1005** option) the application must supply a suitable implementation for 1006** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1007** implementation of sqlite3_os_init() or sqlite3_os_end() 1008** must return [SQLITE_OK] on success and some other [error code] upon 1009** failure. 1010*/ 1011int sqlite3_initialize(void); 1012int sqlite3_shutdown(void); 1013int sqlite3_os_init(void); 1014int sqlite3_os_end(void); 1015 1016/* 1017** CAPI3REF: Configuring The SQLite Library 1018** 1019** The sqlite3_config() interface is used to make global configuration 1020** changes to SQLite in order to tune SQLite to the specific needs of 1021** the application. The default configuration is recommended for most 1022** applications and so this routine is usually not necessary. It is 1023** provided to support rare applications with unusual needs. 1024** 1025** The sqlite3_config() interface is not threadsafe. The application 1026** must insure that no other SQLite interfaces are invoked by other 1027** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1028** may only be invoked prior to library initialization using 1029** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1030** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1031** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1032** Note, however, that ^sqlite3_config() can be called as part of the 1033** implementation of an application-defined [sqlite3_os_init()]. 1034** 1035** The first argument to sqlite3_config() is an integer 1036** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines 1037** what property of SQLite is to be configured. Subsequent arguments 1038** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option] 1039** in the first argument. 1040** 1041** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1042** ^If the option is unknown or SQLite is unable to set the option 1043** then this routine returns a non-zero [error code]. 1044*/ 1045int sqlite3_config(int, ...); 1046 1047/* 1048** CAPI3REF: Configure database connections 1049** 1050** The sqlite3_db_config() interface is used to make configuration 1051** changes to a [database connection]. The interface is similar to 1052** [sqlite3_config()] except that the changes apply to a single 1053** [database connection] (specified in the first argument). The 1054** sqlite3_db_config() interface should only be used immediately after 1055** the database connection is created using [sqlite3_open()], 1056** [sqlite3_open16()], or [sqlite3_open_v2()]. 1057** 1058** The second argument to sqlite3_db_config(D,V,...) is the 1059** configuration verb - an integer code that indicates what 1060** aspect of the [database connection] is being configured. 1061** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE]. 1062** New verbs are likely to be added in future releases of SQLite. 1063** Additional arguments depend on the verb. 1064** 1065** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1066** the call is considered successful. 1067*/ 1068int sqlite3_db_config(sqlite3*, int op, ...); 1069 1070/* 1071** CAPI3REF: Memory Allocation Routines 1072** 1073** An instance of this object defines the interface between SQLite 1074** and low-level memory allocation routines. 1075** 1076** This object is used in only one place in the SQLite interface. 1077** A pointer to an instance of this object is the argument to 1078** [sqlite3_config()] when the configuration option is 1079** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1080** By creating an instance of this object 1081** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1082** during configuration, an application can specify an alternative 1083** memory allocation subsystem for SQLite to use for all of its 1084** dynamic memory needs. 1085** 1086** Note that SQLite comes with several [built-in memory allocators] 1087** that are perfectly adequate for the overwhelming majority of applications 1088** and that this object is only useful to a tiny minority of applications 1089** with specialized memory allocation requirements. This object is 1090** also used during testing of SQLite in order to specify an alternative 1091** memory allocator that simulates memory out-of-memory conditions in 1092** order to verify that SQLite recovers gracefully from such 1093** conditions. 1094** 1095** The xMalloc and xFree methods must work like the 1096** malloc() and free() functions from the standard C library. 1097** The xRealloc method must work like realloc() from the standard C library 1098** with the exception that if the second argument to xRealloc is zero, 1099** xRealloc must be a no-op - it must not perform any allocation or 1100** deallocation. ^SQLite guarantees that the second argument to 1101** xRealloc is always a value returned by a prior call to xRoundup. 1102** And so in cases where xRoundup always returns a positive number, 1103** xRealloc can perform exactly as the standard library realloc() and 1104** still be in compliance with this specification. 1105** 1106** xSize should return the allocated size of a memory allocation 1107** previously obtained from xMalloc or xRealloc. The allocated size 1108** is always at least as big as the requested size but may be larger. 1109** 1110** The xRoundup method returns what would be the allocated size of 1111** a memory allocation given a particular requested size. Most memory 1112** allocators round up memory allocations at least to the next multiple 1113** of 8. Some allocators round up to a larger multiple or to a power of 2. 1114** Every memory allocation request coming in through [sqlite3_malloc()] 1115** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1116** that causes the corresponding memory allocation to fail. 1117** 1118** The xInit method initializes the memory allocator. (For example, 1119** it might allocate any require mutexes or initialize internal data 1120** structures. The xShutdown method is invoked (indirectly) by 1121** [sqlite3_shutdown()] and should deallocate any resources acquired 1122** by xInit. The pAppData pointer is used as the only parameter to 1123** xInit and xShutdown. 1124** 1125** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1126** the xInit method, so the xInit method need not be threadsafe. The 1127** xShutdown method is only called from [sqlite3_shutdown()] so it does 1128** not need to be threadsafe either. For all other methods, SQLite 1129** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1130** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1131** it is by default) and so the methods are automatically serialized. 1132** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1133** methods must be threadsafe or else make their own arrangements for 1134** serialization. 1135** 1136** SQLite will never invoke xInit() more than once without an intervening 1137** call to xShutdown(). 1138*/ 1139typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1140struct sqlite3_mem_methods { 1141 void *(*xMalloc)(int); /* Memory allocation function */ 1142 void (*xFree)(void*); /* Free a prior allocation */ 1143 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1144 int (*xSize)(void*); /* Return the size of an allocation */ 1145 int (*xRoundup)(int); /* Round up request size to allocation size */ 1146 int (*xInit)(void*); /* Initialize the memory allocator */ 1147 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1148 void *pAppData; /* Argument to xInit() and xShutdown() */ 1149}; 1150 1151/* 1152** CAPI3REF: Configuration Options 1153** 1154** These constants are the available integer configuration options that 1155** can be passed as the first argument to the [sqlite3_config()] interface. 1156** 1157** New configuration options may be added in future releases of SQLite. 1158** Existing configuration options might be discontinued. Applications 1159** should check the return code from [sqlite3_config()] to make sure that 1160** the call worked. The [sqlite3_config()] interface will return a 1161** non-zero [error code] if a discontinued or unsupported configuration option 1162** is invoked. 1163** 1164** <dl> 1165** <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1166** <dd>There are no arguments to this option. ^This option sets the 1167** [threading mode] to Single-thread. In other words, it disables 1168** all mutexing and puts SQLite into a mode where it can only be used 1169** by a single thread. ^If SQLite is compiled with 1170** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1171** it is not possible to change the [threading mode] from its default 1172** value of Single-thread and so [sqlite3_config()] will return 1173** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1174** configuration option.</dd> 1175** 1176** <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1177** <dd>There are no arguments to this option. ^This option sets the 1178** [threading mode] to Multi-thread. In other words, it disables 1179** mutexing on [database connection] and [prepared statement] objects. 1180** The application is responsible for serializing access to 1181** [database connections] and [prepared statements]. But other mutexes 1182** are enabled so that SQLite will be safe to use in a multi-threaded 1183** environment as long as no two threads attempt to use the same 1184** [database connection] at the same time. ^If SQLite is compiled with 1185** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1186** it is not possible to set the Multi-thread [threading mode] and 1187** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1188** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1189** 1190** <dt>SQLITE_CONFIG_SERIALIZED</dt> 1191** <dd>There are no arguments to this option. ^This option sets the 1192** [threading mode] to Serialized. In other words, this option enables 1193** all mutexes including the recursive 1194** mutexes on [database connection] and [prepared statement] objects. 1195** In this mode (which is the default when SQLite is compiled with 1196** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1197** to [database connections] and [prepared statements] so that the 1198** application is free to use the same [database connection] or the 1199** same [prepared statement] in different threads at the same time. 1200** ^If SQLite is compiled with 1201** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1202** it is not possible to set the Serialized [threading mode] and 1203** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1204** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1205** 1206** <dt>SQLITE_CONFIG_MALLOC</dt> 1207** <dd> ^(This option takes a single argument which is a pointer to an 1208** instance of the [sqlite3_mem_methods] structure. The argument specifies 1209** alternative low-level memory allocation routines to be used in place of 1210** the memory allocation routines built into SQLite.)^ ^SQLite makes 1211** its own private copy of the content of the [sqlite3_mem_methods] structure 1212** before the [sqlite3_config()] call returns.</dd> 1213** 1214** <dt>SQLITE_CONFIG_GETMALLOC</dt> 1215** <dd> ^(This option takes a single argument which is a pointer to an 1216** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1217** structure is filled with the currently defined memory allocation routines.)^ 1218** This option can be used to overload the default memory allocation 1219** routines with a wrapper that simulations memory allocation failure or 1220** tracks memory usage, for example. </dd> 1221** 1222** <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1223** <dd> ^This option takes single argument of type int, interpreted as a 1224** boolean, which enables or disables the collection of memory allocation 1225** statistics. ^(When memory allocation statistics are disabled, the 1226** following SQLite interfaces become non-operational: 1227** <ul> 1228** <li> [sqlite3_memory_used()] 1229** <li> [sqlite3_memory_highwater()] 1230** <li> [sqlite3_soft_heap_limit()] 1231** <li> [sqlite3_status()] 1232** </ul>)^ 1233** ^Memory allocation statistics are enabled by default unless SQLite is 1234** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1235** allocation statistics are disabled by default. 1236** </dd> 1237** 1238** <dt>SQLITE_CONFIG_SCRATCH</dt> 1239** <dd> ^This option specifies a static memory buffer that SQLite can use for 1240** scratch memory. There are three arguments: A pointer an 8-byte 1241** aligned memory buffer from which the scrach allocations will be 1242** drawn, the size of each scratch allocation (sz), 1243** and the maximum number of scratch allocations (N). The sz 1244** argument must be a multiple of 16. The sz parameter should be a few bytes 1245** larger than the actual scratch space required due to internal overhead. 1246** The first argument must be a pointer to an 8-byte aligned buffer 1247** of at least sz*N bytes of memory. 1248** ^SQLite will use no more than one scratch buffer per thread. So 1249** N should be set to the expected maximum number of threads. ^SQLite will 1250** never require a scratch buffer that is more than 6 times the database 1251** page size. ^If SQLite needs needs additional scratch memory beyond 1252** what is provided by this configuration option, then 1253** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1254** 1255** <dt>SQLITE_CONFIG_PAGECACHE</dt> 1256** <dd> ^This option specifies a static memory buffer that SQLite can use for 1257** the database page cache with the default page cache implemenation. 1258** This configuration should not be used if an application-define page 1259** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option. 1260** There are three arguments to this option: A pointer to 8-byte aligned 1261** memory, the size of each page buffer (sz), and the number of pages (N). 1262** The sz argument should be the size of the largest database page 1263** (a power of two between 512 and 32768) plus a little extra for each 1264** page header. ^The page header size is 20 to 40 bytes depending on 1265** the host architecture. ^It is harmless, apart from the wasted memory, 1266** to make sz a little too large. The first 1267** argument should point to an allocation of at least sz*N bytes of memory. 1268** ^SQLite will use the memory provided by the first argument to satisfy its 1269** memory needs for the first N pages that it adds to cache. ^If additional 1270** page cache memory is needed beyond what is provided by this option, then 1271** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1272** ^The implementation might use one or more of the N buffers to hold 1273** memory accounting information. The pointer in the first argument must 1274** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1275** will be undefined.</dd> 1276** 1277** <dt>SQLITE_CONFIG_HEAP</dt> 1278** <dd> ^This option specifies a static memory buffer that SQLite will use 1279** for all of its dynamic memory allocation needs beyond those provided 1280** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1281** There are three arguments: An 8-byte aligned pointer to the memory, 1282** the number of bytes in the memory buffer, and the minimum allocation size. 1283** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1284** to using its default memory allocator (the system malloc() implementation), 1285** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1286** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1287** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1288** allocator is engaged to handle all of SQLites memory allocation needs. 1289** The first pointer (the memory pointer) must be aligned to an 8-byte 1290** boundary or subsequent behavior of SQLite will be undefined.</dd> 1291** 1292** <dt>SQLITE_CONFIG_MUTEX</dt> 1293** <dd> ^(This option takes a single argument which is a pointer to an 1294** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1295** alternative low-level mutex routines to be used in place 1296** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1297** content of the [sqlite3_mutex_methods] structure before the call to 1298** [sqlite3_config()] returns. ^If SQLite is compiled with 1299** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1300** the entire mutexing subsystem is omitted from the build and hence calls to 1301** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1302** return [SQLITE_ERROR].</dd> 1303** 1304** <dt>SQLITE_CONFIG_GETMUTEX</dt> 1305** <dd> ^(This option takes a single argument which is a pointer to an 1306** instance of the [sqlite3_mutex_methods] structure. The 1307** [sqlite3_mutex_methods] 1308** structure is filled with the currently defined mutex routines.)^ 1309** This option can be used to overload the default mutex allocation 1310** routines with a wrapper used to track mutex usage for performance 1311** profiling or testing, for example. ^If SQLite is compiled with 1312** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1313** the entire mutexing subsystem is omitted from the build and hence calls to 1314** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1315** return [SQLITE_ERROR].</dd> 1316** 1317** <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1318** <dd> ^(This option takes two arguments that determine the default 1319** memory allocation for the lookaside memory allocator on each 1320** [database connection]. The first argument is the 1321** size of each lookaside buffer slot and the second is the number of 1322** slots allocated to each database connection.)^ ^(This option sets the 1323** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1324** verb to [sqlite3_db_config()] can be used to change the lookaside 1325** configuration on individual connections.)^ </dd> 1326** 1327** <dt>SQLITE_CONFIG_PCACHE</dt> 1328** <dd> ^(This option takes a single argument which is a pointer to 1329** an [sqlite3_pcache_methods] object. This object specifies the interface 1330** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1331** object and uses it for page cache memory allocations.</dd> 1332** 1333** <dt>SQLITE_CONFIG_GETPCACHE</dt> 1334** <dd> ^(This option takes a single argument which is a pointer to an 1335** [sqlite3_pcache_methods] object. SQLite copies of the current 1336** page cache implementation into that object.)^ </dd> 1337** 1338** <dt>SQLITE_CONFIG_LOG</dt> 1339** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1340** function with a call signature of void(*)(void*,int,const char*), 1341** and a pointer to void. ^If the function pointer is not NULL, it is 1342** invoked by [sqlite3_log()] to process each logging event. ^If the 1343** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1344** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1345** passed through as the first parameter to the application-defined logger 1346** function whenever that function is invoked. ^The second parameter to 1347** the logger function is a copy of the first parameter to the corresponding 1348** [sqlite3_log()] call and is intended to be a [result code] or an 1349** [extended result code]. ^The third parameter passed to the logger is 1350** log message after formatting via [sqlite3_snprintf()]. 1351** The SQLite logging interface is not reentrant; the logger function 1352** supplied by the application must not invoke any SQLite interface. 1353** In a multi-threaded application, the application-defined logger 1354** function must be threadsafe. </dd> 1355** 1356** </dl> 1357*/ 1358#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1359#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1360#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1361#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1362#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1363#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1364#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1365#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1366#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1367#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1368#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1369/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1370#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1371#define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */ 1372#define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */ 1373#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1374 1375/* 1376** CAPI3REF: Database Connection Configuration Options 1377** 1378** These constants are the available integer configuration options that 1379** can be passed as the second argument to the [sqlite3_db_config()] interface. 1380** 1381** New configuration options may be added in future releases of SQLite. 1382** Existing configuration options might be discontinued. Applications 1383** should check the return code from [sqlite3_db_config()] to make sure that 1384** the call worked. ^The [sqlite3_db_config()] interface will return a 1385** non-zero [error code] if a discontinued or unsupported configuration option 1386** is invoked. 1387** 1388** <dl> 1389** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1390** <dd> ^This option takes three additional arguments that determine the 1391** [lookaside memory allocator] configuration for the [database connection]. 1392** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1393** pointer to an memory buffer to use for lookaside memory. 1394** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1395** may be NULL in which case SQLite will allocate the 1396** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1397** size of each lookaside buffer slot. ^The third argument is the number of 1398** slots. The size of the buffer in the first argument must be greater than 1399** or equal to the product of the second and third arguments. The buffer 1400** must be aligned to an 8-byte boundary. ^If the second argument to 1401** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1402** rounded down to the next smaller 1403** multiple of 8. See also: [SQLITE_CONFIG_LOOKASIDE]</dd> 1404** 1405** </dl> 1406*/ 1407#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1408 1409 1410/* 1411** CAPI3REF: Enable Or Disable Extended Result Codes 1412** 1413** ^The sqlite3_extended_result_codes() routine enables or disables the 1414** [extended result codes] feature of SQLite. ^The extended result 1415** codes are disabled by default for historical compatibility. 1416*/ 1417int sqlite3_extended_result_codes(sqlite3*, int onoff); 1418 1419/* 1420** CAPI3REF: Last Insert Rowid 1421** 1422** ^Each entry in an SQLite table has a unique 64-bit signed 1423** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1424** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1425** names are not also used by explicitly declared columns. ^If 1426** the table has a column of type [INTEGER PRIMARY KEY] then that column 1427** is another alias for the rowid. 1428** 1429** ^This routine returns the [rowid] of the most recent 1430** successful [INSERT] into the database from the [database connection] 1431** in the first argument. ^If no successful [INSERT]s 1432** have ever occurred on that database connection, zero is returned. 1433** 1434** ^(If an [INSERT] occurs within a trigger, then the [rowid] of the inserted 1435** row is returned by this routine as long as the trigger is running. 1436** But once the trigger terminates, the value returned by this routine 1437** reverts to the last value inserted before the trigger fired.)^ 1438** 1439** ^An [INSERT] that fails due to a constraint violation is not a 1440** successful [INSERT] and does not change the value returned by this 1441** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1442** and INSERT OR ABORT make no changes to the return value of this 1443** routine when their insertion fails. ^(When INSERT OR REPLACE 1444** encounters a constraint violation, it does not fail. The 1445** INSERT continues to completion after deleting rows that caused 1446** the constraint problem so INSERT OR REPLACE will always change 1447** the return value of this interface.)^ 1448** 1449** ^For the purposes of this routine, an [INSERT] is considered to 1450** be successful even if it is subsequently rolled back. 1451** 1452** This function is accessible to SQL statements via the 1453** [last_insert_rowid() SQL function]. 1454** 1455** If a separate thread performs a new [INSERT] on the same 1456** database connection while the [sqlite3_last_insert_rowid()] 1457** function is running and thus changes the last insert [rowid], 1458** then the value returned by [sqlite3_last_insert_rowid()] is 1459** unpredictable and might not equal either the old or the new 1460** last insert [rowid]. 1461*/ 1462sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1463 1464/* 1465** CAPI3REF: Count The Number Of Rows Modified 1466** 1467** ^This function returns the number of database rows that were changed 1468** or inserted or deleted by the most recently completed SQL statement 1469** on the [database connection] specified by the first parameter. 1470** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1471** or [DELETE] statement are counted. Auxiliary changes caused by 1472** triggers or [foreign key actions] are not counted.)^ Use the 1473** [sqlite3_total_changes()] function to find the total number of changes 1474** including changes caused by triggers and foreign key actions. 1475** 1476** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1477** are not counted. Only real table changes are counted. 1478** 1479** ^(A "row change" is a change to a single row of a single table 1480** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1481** are changed as side effects of [REPLACE] constraint resolution, 1482** rollback, ABORT processing, [DROP TABLE], or by any other 1483** mechanisms do not count as direct row changes.)^ 1484** 1485** A "trigger context" is a scope of execution that begins and 1486** ends with the script of a [CREATE TRIGGER | trigger]. 1487** Most SQL statements are 1488** evaluated outside of any trigger. This is the "top level" 1489** trigger context. If a trigger fires from the top level, a 1490** new trigger context is entered for the duration of that one 1491** trigger. Subtriggers create subcontexts for their duration. 1492** 1493** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1494** not create a new trigger context. 1495** 1496** ^This function returns the number of direct row changes in the 1497** most recent INSERT, UPDATE, or DELETE statement within the same 1498** trigger context. 1499** 1500** ^Thus, when called from the top level, this function returns the 1501** number of changes in the most recent INSERT, UPDATE, or DELETE 1502** that also occurred at the top level. ^(Within the body of a trigger, 1503** the sqlite3_changes() interface can be called to find the number of 1504** changes in the most recently completed INSERT, UPDATE, or DELETE 1505** statement within the body of the same trigger. 1506** However, the number returned does not include changes 1507** caused by subtriggers since those have their own context.)^ 1508** 1509** See also the [sqlite3_total_changes()] interface, the 1510** [count_changes pragma], and the [changes() SQL function]. 1511** 1512** If a separate thread makes changes on the same database connection 1513** while [sqlite3_changes()] is running then the value returned 1514** is unpredictable and not meaningful. 1515*/ 1516int sqlite3_changes(sqlite3*); 1517 1518/* 1519** CAPI3REF: Total Number Of Rows Modified 1520** 1521** ^This function returns the number of row changes caused by [INSERT], 1522** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1523** ^(The count returned by sqlite3_total_changes() includes all changes 1524** from all [CREATE TRIGGER | trigger] contexts and changes made by 1525** [foreign key actions]. However, 1526** the count does not include changes used to implement [REPLACE] constraints, 1527** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1528** count does not include rows of views that fire an [INSTEAD OF trigger], 1529** though if the INSTEAD OF trigger makes changes of its own, those changes 1530** are counted.)^ 1531** ^The sqlite3_total_changes() function counts the changes as soon as 1532** the statement that makes them is completed (when the statement handle 1533** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1534** 1535** See also the [sqlite3_changes()] interface, the 1536** [count_changes pragma], and the [total_changes() SQL function]. 1537** 1538** If a separate thread makes changes on the same database connection 1539** while [sqlite3_total_changes()] is running then the value 1540** returned is unpredictable and not meaningful. 1541*/ 1542int sqlite3_total_changes(sqlite3*); 1543 1544/* 1545** CAPI3REF: Interrupt A Long-Running Query 1546** 1547** ^This function causes any pending database operation to abort and 1548** return at its earliest opportunity. This routine is typically 1549** called in response to a user action such as pressing "Cancel" 1550** or Ctrl-C where the user wants a long query operation to halt 1551** immediately. 1552** 1553** ^It is safe to call this routine from a thread different from the 1554** thread that is currently running the database operation. But it 1555** is not safe to call this routine with a [database connection] that 1556** is closed or might close before sqlite3_interrupt() returns. 1557** 1558** ^If an SQL operation is very nearly finished at the time when 1559** sqlite3_interrupt() is called, then it might not have an opportunity 1560** to be interrupted and might continue to completion. 1561** 1562** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1563** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1564** that is inside an explicit transaction, then the entire transaction 1565** will be rolled back automatically. 1566** 1567** ^The sqlite3_interrupt(D) call is in effect until all currently running 1568** SQL statements on [database connection] D complete. ^Any new SQL statements 1569** that are started after the sqlite3_interrupt() call and before the 1570** running statements reaches zero are interrupted as if they had been 1571** running prior to the sqlite3_interrupt() call. ^New SQL statements 1572** that are started after the running statement count reaches zero are 1573** not effected by the sqlite3_interrupt(). 1574** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1575** SQL statements is a no-op and has no effect on SQL statements 1576** that are started after the sqlite3_interrupt() call returns. 1577** 1578** If the database connection closes while [sqlite3_interrupt()] 1579** is running then bad things will likely happen. 1580*/ 1581void sqlite3_interrupt(sqlite3*); 1582 1583/* 1584** CAPI3REF: Determine If An SQL Statement Is Complete 1585** 1586** These routines are useful during command-line input to determine if the 1587** currently entered text seems to form a complete SQL statement or 1588** if additional input is needed before sending the text into 1589** SQLite for parsing. ^These routines return 1 if the input string 1590** appears to be a complete SQL statement. ^A statement is judged to be 1591** complete if it ends with a semicolon token and is not a prefix of a 1592** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1593** string literals or quoted identifier names or comments are not 1594** independent tokens (they are part of the token in which they are 1595** embedded) and thus do not count as a statement terminator. ^Whitespace 1596** and comments that follow the final semicolon are ignored. 1597** 1598** ^These routines return 0 if the statement is incomplete. ^If a 1599** memory allocation fails, then SQLITE_NOMEM is returned. 1600** 1601** ^These routines do not parse the SQL statements thus 1602** will not detect syntactically incorrect SQL. 1603** 1604** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1605** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1606** automatically by sqlite3_complete16(). If that initialization fails, 1607** then the return value from sqlite3_complete16() will be non-zero 1608** regardless of whether or not the input SQL is complete.)^ 1609** 1610** The input to [sqlite3_complete()] must be a zero-terminated 1611** UTF-8 string. 1612** 1613** The input to [sqlite3_complete16()] must be a zero-terminated 1614** UTF-16 string in native byte order. 1615*/ 1616int sqlite3_complete(const char *sql); 1617int sqlite3_complete16(const void *sql); 1618 1619/* 1620** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1621** 1622** ^This routine sets a callback function that might be invoked whenever 1623** an attempt is made to open a database table that another thread 1624** or process has locked. 1625** 1626** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1627** is returned immediately upon encountering the lock. ^If the busy callback 1628** is not NULL, then the callback might be invoked with two arguments. 1629** 1630** ^The first argument to the busy handler is a copy of the void* pointer which 1631** is the third argument to sqlite3_busy_handler(). ^The second argument to 1632** the busy handler callback is the number of times that the busy handler has 1633** been invoked for this locking event. ^If the 1634** busy callback returns 0, then no additional attempts are made to 1635** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1636** ^If the callback returns non-zero, then another attempt 1637** is made to open the database for reading and the cycle repeats. 1638** 1639** The presence of a busy handler does not guarantee that it will be invoked 1640** when there is lock contention. ^If SQLite determines that invoking the busy 1641** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1642** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1643** Consider a scenario where one process is holding a read lock that 1644** it is trying to promote to a reserved lock and 1645** a second process is holding a reserved lock that it is trying 1646** to promote to an exclusive lock. The first process cannot proceed 1647** because it is blocked by the second and the second process cannot 1648** proceed because it is blocked by the first. If both processes 1649** invoke the busy handlers, neither will make any progress. Therefore, 1650** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1651** will induce the first process to release its read lock and allow 1652** the second process to proceed. 1653** 1654** ^The default busy callback is NULL. 1655** 1656** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1657** when SQLite is in the middle of a large transaction where all the 1658** changes will not fit into the in-memory cache. SQLite will 1659** already hold a RESERVED lock on the database file, but it needs 1660** to promote this lock to EXCLUSIVE so that it can spill cache 1661** pages into the database file without harm to concurrent 1662** readers. ^If it is unable to promote the lock, then the in-memory 1663** cache will be left in an inconsistent state and so the error 1664** code is promoted from the relatively benign [SQLITE_BUSY] to 1665** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 1666** forces an automatic rollback of the changes. See the 1667** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1668** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1669** this is important. 1670** 1671** ^(There can only be a single busy handler defined for each 1672** [database connection]. Setting a new busy handler clears any 1673** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 1674** will also set or clear the busy handler. 1675** 1676** The busy callback should not take any actions which modify the 1677** database connection that invoked the busy handler. Any such actions 1678** result in undefined behavior. 1679** 1680** A busy handler must not close the database connection 1681** or [prepared statement] that invoked the busy handler. 1682*/ 1683int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1684 1685/* 1686** CAPI3REF: Set A Busy Timeout 1687** 1688** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1689** for a specified amount of time when a table is locked. ^The handler 1690** will sleep multiple times until at least "ms" milliseconds of sleeping 1691** have accumulated. ^After at least "ms" milliseconds of sleeping, 1692** the handler returns 0 which causes [sqlite3_step()] to return 1693** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1694** 1695** ^Calling this routine with an argument less than or equal to zero 1696** turns off all busy handlers. 1697** 1698** ^(There can only be a single busy handler for a particular 1699** [database connection] any any given moment. If another busy handler 1700** was defined (using [sqlite3_busy_handler()]) prior to calling 1701** this routine, that other busy handler is cleared.)^ 1702*/ 1703int sqlite3_busy_timeout(sqlite3*, int ms); 1704 1705/* 1706** CAPI3REF: Convenience Routines For Running Queries 1707** 1708** Definition: A <b>result table</b> is memory data structure created by the 1709** [sqlite3_get_table()] interface. A result table records the 1710** complete query results from one or more queries. 1711** 1712** The table conceptually has a number of rows and columns. But 1713** these numbers are not part of the result table itself. These 1714** numbers are obtained separately. Let N be the number of rows 1715** and M be the number of columns. 1716** 1717** A result table is an array of pointers to zero-terminated UTF-8 strings. 1718** There are (N+1)*M elements in the array. The first M pointers point 1719** to zero-terminated strings that contain the names of the columns. 1720** The remaining entries all point to query results. NULL values result 1721** in NULL pointers. All other values are in their UTF-8 zero-terminated 1722** string representation as returned by [sqlite3_column_text()]. 1723** 1724** A result table might consist of one or more memory allocations. 1725** It is not safe to pass a result table directly to [sqlite3_free()]. 1726** A result table should be deallocated using [sqlite3_free_table()]. 1727** 1728** As an example of the result table format, suppose a query result 1729** is as follows: 1730** 1731** <blockquote><pre> 1732** Name | Age 1733** ----------------------- 1734** Alice | 43 1735** Bob | 28 1736** Cindy | 21 1737** </pre></blockquote> 1738** 1739** There are two column (M==2) and three rows (N==3). Thus the 1740** result table has 8 entries. Suppose the result table is stored 1741** in an array names azResult. Then azResult holds this content: 1742** 1743** <blockquote><pre> 1744** azResult[0] = "Name"; 1745** azResult[1] = "Age"; 1746** azResult[2] = "Alice"; 1747** azResult[3] = "43"; 1748** azResult[4] = "Bob"; 1749** azResult[5] = "28"; 1750** azResult[6] = "Cindy"; 1751** azResult[7] = "21"; 1752** </pre></blockquote> 1753** 1754** ^The sqlite3_get_table() function evaluates one or more 1755** semicolon-separated SQL statements in the zero-terminated UTF-8 1756** string of its 2nd parameter and returns a result table to the 1757** pointer given in its 3rd parameter. 1758** 1759** After the application has finished with the result from sqlite3_get_table(), 1760** it should pass the result table pointer to sqlite3_free_table() in order to 1761** release the memory that was malloced. Because of the way the 1762** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1763** function must not try to call [sqlite3_free()] directly. Only 1764** [sqlite3_free_table()] is able to release the memory properly and safely. 1765** 1766** ^(The sqlite3_get_table() interface is implemented as a wrapper around 1767** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 1768** to any internal data structures of SQLite. It uses only the public 1769** interface defined here. As a consequence, errors that occur in the 1770** wrapper layer outside of the internal [sqlite3_exec()] call are not 1771** reflected in subsequent calls to [sqlite3_errcode()] or 1772** [sqlite3_errmsg()].)^ 1773*/ 1774int sqlite3_get_table( 1775 sqlite3 *db, /* An open database */ 1776 const char *zSql, /* SQL to be evaluated */ 1777 char ***pazResult, /* Results of the query */ 1778 int *pnRow, /* Number of result rows written here */ 1779 int *pnColumn, /* Number of result columns written here */ 1780 char **pzErrmsg /* Error msg written here */ 1781); 1782void sqlite3_free_table(char **result); 1783 1784/* 1785** CAPI3REF: Formatted String Printing Functions 1786** 1787** These routines are work-alikes of the "printf()" family of functions 1788** from the standard C library. 1789** 1790** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 1791** results into memory obtained from [sqlite3_malloc()]. 1792** The strings returned by these two routines should be 1793** released by [sqlite3_free()]. ^Both routines return a 1794** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 1795** memory to hold the resulting string. 1796** 1797** ^(In sqlite3_snprintf() routine is similar to "snprintf()" from 1798** the standard C library. The result is written into the 1799** buffer supplied as the second parameter whose size is given by 1800** the first parameter. Note that the order of the 1801** first two parameters is reversed from snprintf().)^ This is an 1802** historical accident that cannot be fixed without breaking 1803** backwards compatibility. ^(Note also that sqlite3_snprintf() 1804** returns a pointer to its buffer instead of the number of 1805** characters actually written into the buffer.)^ We admit that 1806** the number of characters written would be a more useful return 1807** value but we cannot change the implementation of sqlite3_snprintf() 1808** now without breaking compatibility. 1809** 1810** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 1811** guarantees that the buffer is always zero-terminated. ^The first 1812** parameter "n" is the total size of the buffer, including space for 1813** the zero terminator. So the longest string that can be completely 1814** written will be n-1 characters. 1815** 1816** These routines all implement some additional formatting 1817** options that are useful for constructing SQL statements. 1818** All of the usual printf() formatting options apply. In addition, there 1819** is are "%q", "%Q", and "%z" options. 1820** 1821** ^(The %q option works like %s in that it substitutes a null-terminated 1822** string from the argument list. But %q also doubles every '\'' character. 1823** %q is designed for use inside a string literal.)^ By doubling each '\'' 1824** character it escapes that character and allows it to be inserted into 1825** the string. 1826** 1827** For example, assume the string variable zText contains text as follows: 1828** 1829** <blockquote><pre> 1830** char *zText = "It's a happy day!"; 1831** </pre></blockquote> 1832** 1833** One can use this text in an SQL statement as follows: 1834** 1835** <blockquote><pre> 1836** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 1837** sqlite3_exec(db, zSQL, 0, 0, 0); 1838** sqlite3_free(zSQL); 1839** </pre></blockquote> 1840** 1841** Because the %q format string is used, the '\'' character in zText 1842** is escaped and the SQL generated is as follows: 1843** 1844** <blockquote><pre> 1845** INSERT INTO table1 VALUES('It''s a happy day!') 1846** </pre></blockquote> 1847** 1848** This is correct. Had we used %s instead of %q, the generated SQL 1849** would have looked like this: 1850** 1851** <blockquote><pre> 1852** INSERT INTO table1 VALUES('It's a happy day!'); 1853** </pre></blockquote> 1854** 1855** This second example is an SQL syntax error. As a general rule you should 1856** always use %q instead of %s when inserting text into a string literal. 1857** 1858** ^(The %Q option works like %q except it also adds single quotes around 1859** the outside of the total string. Additionally, if the parameter in the 1860** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 1861** single quotes).)^ So, for example, one could say: 1862** 1863** <blockquote><pre> 1864** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 1865** sqlite3_exec(db, zSQL, 0, 0, 0); 1866** sqlite3_free(zSQL); 1867** </pre></blockquote> 1868** 1869** The code above will render a correct SQL statement in the zSQL 1870** variable even if the zText variable is a NULL pointer. 1871** 1872** ^(The "%z" formatting option works like "%s" but with the 1873** addition that after the string has been read and copied into 1874** the result, [sqlite3_free()] is called on the input string.)^ 1875*/ 1876char *sqlite3_mprintf(const char*,...); 1877char *sqlite3_vmprintf(const char*, va_list); 1878char *sqlite3_snprintf(int,char*,const char*, ...); 1879 1880/* 1881** CAPI3REF: Memory Allocation Subsystem 1882** 1883** The SQLite core uses these three routines for all of its own 1884** internal memory allocation needs. "Core" in the previous sentence 1885** does not include operating-system specific VFS implementation. The 1886** Windows VFS uses native malloc() and free() for some operations. 1887** 1888** ^The sqlite3_malloc() routine returns a pointer to a block 1889** of memory at least N bytes in length, where N is the parameter. 1890** ^If sqlite3_malloc() is unable to obtain sufficient free 1891** memory, it returns a NULL pointer. ^If the parameter N to 1892** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 1893** a NULL pointer. 1894** 1895** ^Calling sqlite3_free() with a pointer previously returned 1896** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 1897** that it might be reused. ^The sqlite3_free() routine is 1898** a no-op if is called with a NULL pointer. Passing a NULL pointer 1899** to sqlite3_free() is harmless. After being freed, memory 1900** should neither be read nor written. Even reading previously freed 1901** memory might result in a segmentation fault or other severe error. 1902** Memory corruption, a segmentation fault, or other severe error 1903** might result if sqlite3_free() is called with a non-NULL pointer that 1904** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 1905** 1906** ^(The sqlite3_realloc() interface attempts to resize a 1907** prior memory allocation to be at least N bytes, where N is the 1908** second parameter. The memory allocation to be resized is the first 1909** parameter.)^ ^ If the first parameter to sqlite3_realloc() 1910** is a NULL pointer then its behavior is identical to calling 1911** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 1912** ^If the second parameter to sqlite3_realloc() is zero or 1913** negative then the behavior is exactly the same as calling 1914** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 1915** ^sqlite3_realloc() returns a pointer to a memory allocation 1916** of at least N bytes in size or NULL if sufficient memory is unavailable. 1917** ^If M is the size of the prior allocation, then min(N,M) bytes 1918** of the prior allocation are copied into the beginning of buffer returned 1919** by sqlite3_realloc() and the prior allocation is freed. 1920** ^If sqlite3_realloc() returns NULL, then the prior allocation 1921** is not freed. 1922** 1923** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 1924** is always aligned to at least an 8 byte boundary. 1925** 1926** In SQLite version 3.5.0 and 3.5.1, it was possible to define 1927** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 1928** implementation of these routines to be omitted. That capability 1929** is no longer provided. Only built-in memory allocators can be used. 1930** 1931** The Windows OS interface layer calls 1932** the system malloc() and free() directly when converting 1933** filenames between the UTF-8 encoding used by SQLite 1934** and whatever filename encoding is used by the particular Windows 1935** installation. Memory allocation errors are detected, but 1936** they are reported back as [SQLITE_CANTOPEN] or 1937** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 1938** 1939** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 1940** must be either NULL or else pointers obtained from a prior 1941** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 1942** not yet been released. 1943** 1944** The application must not read or write any part of 1945** a block of memory after it has been released using 1946** [sqlite3_free()] or [sqlite3_realloc()]. 1947*/ 1948void *sqlite3_malloc(int); 1949void *sqlite3_realloc(void*, int); 1950void sqlite3_free(void*); 1951 1952/* 1953** CAPI3REF: Memory Allocator Statistics 1954** 1955** SQLite provides these two interfaces for reporting on the status 1956** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 1957** routines, which form the built-in memory allocation subsystem. 1958** 1959** ^The [sqlite3_memory_used()] routine returns the number of bytes 1960** of memory currently outstanding (malloced but not freed). 1961** ^The [sqlite3_memory_highwater()] routine returns the maximum 1962** value of [sqlite3_memory_used()] since the high-water mark 1963** was last reset. ^The values returned by [sqlite3_memory_used()] and 1964** [sqlite3_memory_highwater()] include any overhead 1965** added by SQLite in its implementation of [sqlite3_malloc()], 1966** but not overhead added by the any underlying system library 1967** routines that [sqlite3_malloc()] may call. 1968** 1969** ^The memory high-water mark is reset to the current value of 1970** [sqlite3_memory_used()] if and only if the parameter to 1971** [sqlite3_memory_highwater()] is true. ^The value returned 1972** by [sqlite3_memory_highwater(1)] is the high-water mark 1973** prior to the reset. 1974*/ 1975sqlite3_int64 sqlite3_memory_used(void); 1976sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 1977 1978/* 1979** CAPI3REF: Pseudo-Random Number Generator 1980** 1981** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 1982** select random [ROWID | ROWIDs] when inserting new records into a table that 1983** already uses the largest possible [ROWID]. The PRNG is also used for 1984** the build-in random() and randomblob() SQL functions. This interface allows 1985** applications to access the same PRNG for other purposes. 1986** 1987** ^A call to this routine stores N bytes of randomness into buffer P. 1988** 1989** ^The first time this routine is invoked (either internally or by 1990** the application) the PRNG is seeded using randomness obtained 1991** from the xRandomness method of the default [sqlite3_vfs] object. 1992** ^On all subsequent invocations, the pseudo-randomness is generated 1993** internally and without recourse to the [sqlite3_vfs] xRandomness 1994** method. 1995*/ 1996void sqlite3_randomness(int N, void *P); 1997 1998/* 1999** CAPI3REF: Compile-Time Authorization Callbacks 2000** 2001** ^This routine registers a authorizer callback with a particular 2002** [database connection], supplied in the first argument. 2003** ^The authorizer callback is invoked as SQL statements are being compiled 2004** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2005** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2006** points during the compilation process, as logic is being created 2007** to perform various actions, the authorizer callback is invoked to 2008** see if those actions are allowed. ^The authorizer callback should 2009** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2010** specific action but allow the SQL statement to continue to be 2011** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2012** rejected with an error. ^If the authorizer callback returns 2013** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2014** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2015** the authorizer will fail with an error message. 2016** 2017** When the callback returns [SQLITE_OK], that means the operation 2018** requested is ok. ^When the callback returns [SQLITE_DENY], the 2019** [sqlite3_prepare_v2()] or equivalent call that triggered the 2020** authorizer will fail with an error message explaining that 2021** access is denied. 2022** 2023** ^The first parameter to the authorizer callback is a copy of the third 2024** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2025** to the callback is an integer [SQLITE_COPY | action code] that specifies 2026** the particular action to be authorized. ^The third through sixth parameters 2027** to the callback are zero-terminated strings that contain additional 2028** details about the action to be authorized. 2029** 2030** ^If the action code is [SQLITE_READ] 2031** and the callback returns [SQLITE_IGNORE] then the 2032** [prepared statement] statement is constructed to substitute 2033** a NULL value in place of the table column that would have 2034** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2035** return can be used to deny an untrusted user access to individual 2036** columns of a table. 2037** ^If the action code is [SQLITE_DELETE] and the callback returns 2038** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2039** [truncate optimization] is disabled and all rows are deleted individually. 2040** 2041** An authorizer is used when [sqlite3_prepare | preparing] 2042** SQL statements from an untrusted source, to ensure that the SQL statements 2043** do not try to access data they are not allowed to see, or that they do not 2044** try to execute malicious statements that damage the database. For 2045** example, an application may allow a user to enter arbitrary 2046** SQL queries for evaluation by a database. But the application does 2047** not want the user to be able to make arbitrary changes to the 2048** database. An authorizer could then be put in place while the 2049** user-entered SQL is being [sqlite3_prepare | prepared] that 2050** disallows everything except [SELECT] statements. 2051** 2052** Applications that need to process SQL from untrusted sources 2053** might also consider lowering resource limits using [sqlite3_limit()] 2054** and limiting database size using the [max_page_count] [PRAGMA] 2055** in addition to using an authorizer. 2056** 2057** ^(Only a single authorizer can be in place on a database connection 2058** at a time. Each call to sqlite3_set_authorizer overrides the 2059** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2060** The authorizer is disabled by default. 2061** 2062** The authorizer callback must not do anything that will modify 2063** the database connection that invoked the authorizer callback. 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** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2068** statement might be re-prepared during [sqlite3_step()] due to a 2069** schema change. Hence, the application should ensure that the 2070** correct authorizer callback remains in place during the [sqlite3_step()]. 2071** 2072** ^Note that the authorizer callback is invoked only during 2073** [sqlite3_prepare()] or its variants. Authorization is not 2074** performed during statement evaluation in [sqlite3_step()], unless 2075** as stated in the previous paragraph, sqlite3_step() invokes 2076** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2077*/ 2078int sqlite3_set_authorizer( 2079 sqlite3*, 2080 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2081 void *pUserData 2082); 2083 2084/* 2085** CAPI3REF: Authorizer Return Codes 2086** 2087** The [sqlite3_set_authorizer | authorizer callback function] must 2088** return either [SQLITE_OK] or one of these two constants in order 2089** to signal SQLite whether or not the action is permitted. See the 2090** [sqlite3_set_authorizer | authorizer documentation] for additional 2091** information. 2092*/ 2093#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2094#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2095 2096/* 2097** CAPI3REF: Authorizer Action Codes 2098** 2099** The [sqlite3_set_authorizer()] interface registers a callback function 2100** that is invoked to authorize certain SQL statement actions. The 2101** second parameter to the callback is an integer code that specifies 2102** what action is being authorized. These are the integer action codes that 2103** the authorizer callback may be passed. 2104** 2105** These action code values signify what kind of operation is to be 2106** authorized. The 3rd and 4th parameters to the authorization 2107** callback function will be parameters or NULL depending on which of these 2108** codes is used as the second parameter. ^(The 5th parameter to the 2109** authorizer callback is the name of the database ("main", "temp", 2110** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2111** is the name of the inner-most trigger or view that is responsible for 2112** the access attempt or NULL if this access attempt is directly from 2113** top-level SQL code. 2114*/ 2115/******************************************* 3rd ************ 4th ***********/ 2116#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2117#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2118#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2119#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2120#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2121#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2122#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2123#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2124#define SQLITE_DELETE 9 /* Table Name NULL */ 2125#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2126#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2127#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2128#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2129#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2130#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2131#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2132#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2133#define SQLITE_INSERT 18 /* Table Name NULL */ 2134#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2135#define SQLITE_READ 20 /* Table Name Column Name */ 2136#define SQLITE_SELECT 21 /* NULL NULL */ 2137#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2138#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2139#define SQLITE_ATTACH 24 /* Filename NULL */ 2140#define SQLITE_DETACH 25 /* Database Name NULL */ 2141#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2142#define SQLITE_REINDEX 27 /* Index Name NULL */ 2143#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2144#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2145#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2146#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2147#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2148#define SQLITE_COPY 0 /* No longer used */ 2149 2150/* 2151** CAPI3REF: Tracing And Profiling Functions 2152** 2153** These routines register callback functions that can be used for 2154** tracing and profiling the execution of SQL statements. 2155** 2156** ^The callback function registered by sqlite3_trace() is invoked at 2157** various times when an SQL statement is being run by [sqlite3_step()]. 2158** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2159** SQL statement text as the statement first begins executing. 2160** ^(Additional sqlite3_trace() callbacks might occur 2161** as each triggered subprogram is entered. The callbacks for triggers 2162** contain a UTF-8 SQL comment that identifies the trigger.)^ 2163** 2164** ^The callback function registered by sqlite3_profile() is invoked 2165** as each SQL statement finishes. ^The profile callback contains 2166** the original statement text and an estimate of wall-clock time 2167** of how long that statement took to run. 2168*/ 2169void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2170SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2171 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2172 2173/* 2174** CAPI3REF: Query Progress Callbacks 2175** 2176** ^This routine configures a callback function - the 2177** progress callback - that is invoked periodically during long 2178** running calls to [sqlite3_exec()], [sqlite3_step()] and 2179** [sqlite3_get_table()]. An example use for this 2180** interface is to keep a GUI updated during a large query. 2181** 2182** ^If the progress callback returns non-zero, the operation is 2183** interrupted. This feature can be used to implement a 2184** "Cancel" button on a GUI progress dialog box. 2185** 2186** The progress handler must not do anything that will modify 2187** the database connection that invoked the progress handler. 2188** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2189** database connections for the meaning of "modify" in this paragraph. 2190** 2191*/ 2192void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2193 2194/* 2195** CAPI3REF: Opening A New Database Connection 2196** 2197** ^These routines open an SQLite database file whose name is given by the 2198** filename argument. ^The filename argument is interpreted as UTF-8 for 2199** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2200** order for sqlite3_open16(). ^(A [database connection] handle is usually 2201** returned in *ppDb, even if an error occurs. The only exception is that 2202** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2203** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2204** object.)^ ^(If the database is opened (and/or created) successfully, then 2205** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2206** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2207** an English language description of the error following a failure of any 2208** of the sqlite3_open() routines. 2209** 2210** ^The default encoding for the database will be UTF-8 if 2211** sqlite3_open() or sqlite3_open_v2() is called and 2212** UTF-16 in the native byte order if sqlite3_open16() is used. 2213** 2214** Whether or not an error occurs when it is opened, resources 2215** associated with the [database connection] handle should be released by 2216** passing it to [sqlite3_close()] when it is no longer required. 2217** 2218** The sqlite3_open_v2() interface works like sqlite3_open() 2219** except that it accepts two additional parameters for additional control 2220** over the new database connection. ^(The flags parameter to 2221** sqlite3_open_v2() can take one of 2222** the following three values, optionally combined with the 2223** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2224** and/or [SQLITE_OPEN_PRIVATECACHE] flags:)^ 2225** 2226** <dl> 2227** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2228** <dd>The database is opened in read-only mode. If the database does not 2229** already exist, an error is returned.</dd>)^ 2230** 2231** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2232** <dd>The database is opened for reading and writing if possible, or reading 2233** only if the file is write protected by the operating system. In either 2234** case the database must already exist, otherwise an error is returned.</dd>)^ 2235** 2236** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2237** <dd>The database is opened for reading and writing, and is creates it if 2238** it does not already exist. This is the behavior that is always used for 2239** sqlite3_open() and sqlite3_open16().</dd>)^ 2240** </dl> 2241** 2242** If the 3rd parameter to sqlite3_open_v2() is not one of the 2243** combinations shown above or one of the combinations shown above combined 2244** with the [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], 2245** [SQLITE_OPEN_SHAREDCACHE] and/or [SQLITE_OPEN_SHAREDCACHE] flags, 2246** then the behavior is undefined. 2247** 2248** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2249** opens in the multi-thread [threading mode] as long as the single-thread 2250** mode has not been set at compile-time or start-time. ^If the 2251** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2252** in the serialized [threading mode] unless single-thread was 2253** previously selected at compile-time or start-time. 2254** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2255** eligible to use [shared cache mode], regardless of whether or not shared 2256** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2257** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2258** participate in [shared cache mode] even if it is enabled. 2259** 2260** ^If the filename is ":memory:", then a private, temporary in-memory database 2261** is created for the connection. ^This in-memory database will vanish when 2262** the database connection is closed. Future versions of SQLite might 2263** make use of additional special filenames that begin with the ":" character. 2264** It is recommended that when a database filename actually does begin with 2265** a ":" character you should prefix the filename with a pathname such as 2266** "./" to avoid ambiguity. 2267** 2268** ^If the filename is an empty string, then a private, temporary 2269** on-disk database will be created. ^This private database will be 2270** automatically deleted as soon as the database connection is closed. 2271** 2272** ^The fourth parameter to sqlite3_open_v2() is the name of the 2273** [sqlite3_vfs] object that defines the operating system interface that 2274** the new database connection should use. ^If the fourth parameter is 2275** a NULL pointer then the default [sqlite3_vfs] object is used. 2276** 2277** <b>Note to Windows users:</b> The encoding used for the filename argument 2278** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2279** codepage is currently defined. Filenames containing international 2280** characters must be converted to UTF-8 prior to passing them into 2281** sqlite3_open() or sqlite3_open_v2(). 2282*/ 2283int sqlite3_open( 2284 const char *filename, /* Database filename (UTF-8) */ 2285 sqlite3 **ppDb /* OUT: SQLite db handle */ 2286); 2287int sqlite3_open16( 2288 const void *filename, /* Database filename (UTF-16) */ 2289 sqlite3 **ppDb /* OUT: SQLite db handle */ 2290); 2291int sqlite3_open_v2( 2292 const char *filename, /* Database filename (UTF-8) */ 2293 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2294 int flags, /* Flags */ 2295 const char *zVfs /* Name of VFS module to use */ 2296); 2297 2298/* 2299** CAPI3REF: Error Codes And Messages 2300** 2301** ^The sqlite3_errcode() interface returns the numeric [result code] or 2302** [extended result code] for the most recent failed sqlite3_* API call 2303** associated with a [database connection]. If a prior API call failed 2304** but the most recent API call succeeded, the return value from 2305** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2306** interface is the same except that it always returns the 2307** [extended result code] even when extended result codes are 2308** disabled. 2309** 2310** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2311** text that describes the error, as either UTF-8 or UTF-16 respectively. 2312** ^(Memory to hold the error message string is managed internally. 2313** The application does not need to worry about freeing the result. 2314** However, the error string might be overwritten or deallocated by 2315** subsequent calls to other SQLite interface functions.)^ 2316** 2317** When the serialized [threading mode] is in use, it might be the 2318** case that a second error occurs on a separate thread in between 2319** the time of the first error and the call to these interfaces. 2320** When that happens, the second error will be reported since these 2321** interfaces always report the most recent result. To avoid 2322** this, each thread can obtain exclusive use of the [database connection] D 2323** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2324** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2325** all calls to the interfaces listed here are completed. 2326** 2327** If an interface fails with SQLITE_MISUSE, that means the interface 2328** was invoked incorrectly by the application. In that case, the 2329** error code and message may or may not be set. 2330*/ 2331int sqlite3_errcode(sqlite3 *db); 2332int sqlite3_extended_errcode(sqlite3 *db); 2333const char *sqlite3_errmsg(sqlite3*); 2334const void *sqlite3_errmsg16(sqlite3*); 2335 2336/* 2337** CAPI3REF: SQL Statement Object 2338** KEYWORDS: {prepared statement} {prepared statements} 2339** 2340** An instance of this object represents a single SQL statement. 2341** This object is variously known as a "prepared statement" or a 2342** "compiled SQL statement" or simply as a "statement". 2343** 2344** The life of a statement object goes something like this: 2345** 2346** <ol> 2347** <li> Create the object using [sqlite3_prepare_v2()] or a related 2348** function. 2349** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2350** interfaces. 2351** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2352** <li> Reset the statement using [sqlite3_reset()] then go back 2353** to step 2. Do this zero or more times. 2354** <li> Destroy the object using [sqlite3_finalize()]. 2355** </ol> 2356** 2357** Refer to documentation on individual methods above for additional 2358** information. 2359*/ 2360typedef struct sqlite3_stmt sqlite3_stmt; 2361 2362/* 2363** CAPI3REF: Run-time Limits 2364** 2365** ^(This interface allows the size of various constructs to be limited 2366** on a connection by connection basis. The first parameter is the 2367** [database connection] whose limit is to be set or queried. The 2368** second parameter is one of the [limit categories] that define a 2369** class of constructs to be size limited. The third parameter is the 2370** new limit for that construct. The function returns the old limit.)^ 2371** 2372** ^If the new limit is a negative number, the limit is unchanged. 2373** ^(For the limit category of SQLITE_LIMIT_XYZ there is a 2374** [limits | hard upper bound] 2375** set by a compile-time C preprocessor macro named 2376** [limits | SQLITE_MAX_XYZ]. 2377** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2378** ^Attempts to increase a limit above its hard upper bound are 2379** silently truncated to the hard upper bound. 2380** 2381** Run-time limits are intended for use in applications that manage 2382** both their own internal database and also databases that are controlled 2383** by untrusted external sources. An example application might be a 2384** web browser that has its own databases for storing history and 2385** separate databases controlled by JavaScript applications downloaded 2386** off the Internet. The internal databases can be given the 2387** large, default limits. Databases managed by external sources can 2388** be given much smaller limits designed to prevent a denial of service 2389** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2390** interface to further control untrusted SQL. The size of the database 2391** created by an untrusted script can be contained using the 2392** [max_page_count] [PRAGMA]. 2393** 2394** New run-time limit categories may be added in future releases. 2395*/ 2396int sqlite3_limit(sqlite3*, int id, int newVal); 2397 2398/* 2399** CAPI3REF: Run-Time Limit Categories 2400** KEYWORDS: {limit category} {*limit categories} 2401** 2402** These constants define various performance limits 2403** that can be lowered at run-time using [sqlite3_limit()]. 2404** The synopsis of the meanings of the various limits is shown below. 2405** Additional information is available at [limits | Limits in SQLite]. 2406** 2407** <dl> 2408** ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2409** <dd>The maximum size of any string or BLOB or table row.<dd>)^ 2410** 2411** ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2412** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2413** 2414** ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2415** <dd>The maximum number of columns in a table definition or in the 2416** result set of a [SELECT] or the maximum number of columns in an index 2417** or in an ORDER BY or GROUP BY clause.</dd>)^ 2418** 2419** ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2420** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2421** 2422** ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2423** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2424** 2425** ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2426** <dd>The maximum number of instructions in a virtual machine program 2427** used to implement an SQL statement.</dd>)^ 2428** 2429** ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2430** <dd>The maximum number of arguments on a function.</dd>)^ 2431** 2432** ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2433** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2434** 2435** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2436** <dd>The maximum length of the pattern argument to the [LIKE] or 2437** [GLOB] operators.</dd>)^ 2438** 2439** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2440** <dd>The maximum number of variables in an SQL statement that can 2441** be bound.</dd>)^ 2442** 2443** ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2444** <dd>The maximum depth of recursion for triggers.</dd>)^ 2445** </dl> 2446*/ 2447#define SQLITE_LIMIT_LENGTH 0 2448#define SQLITE_LIMIT_SQL_LENGTH 1 2449#define SQLITE_LIMIT_COLUMN 2 2450#define SQLITE_LIMIT_EXPR_DEPTH 3 2451#define SQLITE_LIMIT_COMPOUND_SELECT 4 2452#define SQLITE_LIMIT_VDBE_OP 5 2453#define SQLITE_LIMIT_FUNCTION_ARG 6 2454#define SQLITE_LIMIT_ATTACHED 7 2455#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2456#define SQLITE_LIMIT_VARIABLE_NUMBER 9 2457#define SQLITE_LIMIT_TRIGGER_DEPTH 10 2458 2459/* 2460** CAPI3REF: Compiling An SQL Statement 2461** KEYWORDS: {SQL statement compiler} 2462** 2463** To execute an SQL query, it must first be compiled into a byte-code 2464** program using one of these routines. 2465** 2466** The first argument, "db", is a [database connection] obtained from a 2467** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2468** [sqlite3_open16()]. The database connection must not have been closed. 2469** 2470** The second argument, "zSql", is the statement to be compiled, encoded 2471** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2472** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2473** use UTF-16. 2474** 2475** ^If the nByte argument is less than zero, then zSql is read up to the 2476** first zero terminator. ^If nByte is non-negative, then it is the maximum 2477** number of bytes read from zSql. ^When nByte is non-negative, the 2478** zSql string ends at either the first '\000' or '\u0000' character or 2479** the nByte-th byte, whichever comes first. If the caller knows 2480** that the supplied string is nul-terminated, then there is a small 2481** performance advantage to be gained by passing an nByte parameter that 2482** is equal to the number of bytes in the input string <i>including</i> 2483** the nul-terminator bytes. 2484** 2485** ^If pzTail is not NULL then *pzTail is made to point to the first byte 2486** past the end of the first SQL statement in zSql. These routines only 2487** compile the first statement in zSql, so *pzTail is left pointing to 2488** what remains uncompiled. 2489** 2490** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 2491** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 2492** to NULL. ^If the input text contains no SQL (if the input is an empty 2493** string or a comment) then *ppStmt is set to NULL. 2494** The calling procedure is responsible for deleting the compiled 2495** SQL statement using [sqlite3_finalize()] after it has finished with it. 2496** ppStmt may not be NULL. 2497** 2498** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 2499** otherwise an [error code] is returned. 2500** 2501** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2502** recommended for all new programs. The two older interfaces are retained 2503** for backwards compatibility, but their use is discouraged. 2504** ^In the "v2" interfaces, the prepared statement 2505** that is returned (the [sqlite3_stmt] object) contains a copy of the 2506** original SQL text. This causes the [sqlite3_step()] interface to 2507** behave differently in three ways: 2508** 2509** <ol> 2510** <li> 2511** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2512** always used to do, [sqlite3_step()] will automatically recompile the SQL 2513** statement and try to run it again. ^If the schema has changed in 2514** a way that makes the statement no longer valid, [sqlite3_step()] will still 2515** return [SQLITE_SCHEMA]. But unlike the legacy behavior, [SQLITE_SCHEMA] is 2516** now a fatal error. Calling [sqlite3_prepare_v2()] again will not make the 2517** error go away. Note: use [sqlite3_errmsg()] to find the text 2518** of the parsing error that results in an [SQLITE_SCHEMA] return. 2519** </li> 2520** 2521** <li> 2522** ^When an error occurs, [sqlite3_step()] will return one of the detailed 2523** [error codes] or [extended error codes]. ^The legacy behavior was that 2524** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2525** and the application would have to make a second call to [sqlite3_reset()] 2526** in order to find the underlying cause of the problem. With the "v2" prepare 2527** interfaces, the underlying reason for the error is returned immediately. 2528** </li> 2529** 2530** <li> 2531** ^If the value of a [parameter | host parameter] in the WHERE clause might 2532** change the query plan for a statement, then the statement may be 2533** automatically recompiled (as if there had been a schema change) on the first 2534** [sqlite3_step()] call following any change to the 2535** [sqlite3_bind_text | bindings] of the [parameter]. 2536** </li> 2537** </ol> 2538*/ 2539int sqlite3_prepare( 2540 sqlite3 *db, /* Database handle */ 2541 const char *zSql, /* SQL statement, UTF-8 encoded */ 2542 int nByte, /* Maximum length of zSql in bytes. */ 2543 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2544 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2545); 2546int sqlite3_prepare_v2( 2547 sqlite3 *db, /* Database handle */ 2548 const char *zSql, /* SQL statement, UTF-8 encoded */ 2549 int nByte, /* Maximum length of zSql in bytes. */ 2550 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2551 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2552); 2553int sqlite3_prepare16( 2554 sqlite3 *db, /* Database handle */ 2555 const void *zSql, /* SQL statement, UTF-16 encoded */ 2556 int nByte, /* Maximum length of zSql in bytes. */ 2557 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2558 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2559); 2560int sqlite3_prepare16_v2( 2561 sqlite3 *db, /* Database handle */ 2562 const void *zSql, /* SQL statement, UTF-16 encoded */ 2563 int nByte, /* Maximum length of zSql in bytes. */ 2564 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2565 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2566); 2567 2568/* 2569** CAPI3REF: Retrieving Statement SQL 2570** 2571** ^This interface can be used to retrieve a saved copy of the original 2572** SQL text used to create a [prepared statement] if that statement was 2573** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2574*/ 2575const char *sqlite3_sql(sqlite3_stmt *pStmt); 2576 2577/* 2578** CAPI3REF: Dynamically Typed Value Object 2579** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 2580** 2581** SQLite uses the sqlite3_value object to represent all values 2582** that can be stored in a database table. SQLite uses dynamic typing 2583** for the values it stores. ^Values stored in sqlite3_value objects 2584** can be integers, floating point values, strings, BLOBs, or NULL. 2585** 2586** An sqlite3_value object may be either "protected" or "unprotected". 2587** Some interfaces require a protected sqlite3_value. Other interfaces 2588** will accept either a protected or an unprotected sqlite3_value. 2589** Every interface that accepts sqlite3_value arguments specifies 2590** whether or not it requires a protected sqlite3_value. 2591** 2592** The terms "protected" and "unprotected" refer to whether or not 2593** a mutex is held. A internal mutex is held for a protected 2594** sqlite3_value object but no mutex is held for an unprotected 2595** sqlite3_value object. If SQLite is compiled to be single-threaded 2596** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 2597** or if SQLite is run in one of reduced mutex modes 2598** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 2599** then there is no distinction between protected and unprotected 2600** sqlite3_value objects and they can be used interchangeably. However, 2601** for maximum code portability it is recommended that applications 2602** still make the distinction between between protected and unprotected 2603** sqlite3_value objects even when not strictly required. 2604** 2605** ^The sqlite3_value objects that are passed as parameters into the 2606** implementation of [application-defined SQL functions] are protected. 2607** ^The sqlite3_value object returned by 2608** [sqlite3_column_value()] is unprotected. 2609** Unprotected sqlite3_value objects may only be used with 2610** [sqlite3_result_value()] and [sqlite3_bind_value()]. 2611** The [sqlite3_value_blob | sqlite3_value_type()] family of 2612** interfaces require protected sqlite3_value objects. 2613*/ 2614typedef struct Mem sqlite3_value; 2615 2616/* 2617** CAPI3REF: SQL Function Context Object 2618** 2619** The context in which an SQL function executes is stored in an 2620** sqlite3_context object. ^A pointer to an sqlite3_context object 2621** is always first parameter to [application-defined SQL functions]. 2622** The application-defined SQL function implementation will pass this 2623** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 2624** [sqlite3_aggregate_context()], [sqlite3_user_data()], 2625** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 2626** and/or [sqlite3_set_auxdata()]. 2627*/ 2628typedef struct sqlite3_context sqlite3_context; 2629 2630/* 2631** CAPI3REF: Binding Values To Prepared Statements 2632** KEYWORDS: {host parameter} {host parameters} {host parameter name} 2633** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 2634** 2635** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 2636** literals may be replaced by a [parameter] that matches one of following 2637** templates: 2638** 2639** <ul> 2640** <li> ? 2641** <li> ?NNN 2642** <li> :VVV 2643** <li> @VVV 2644** <li> $VVV 2645** </ul> 2646** 2647** In the templates above, NNN represents an integer literal, 2648** and VVV represents an alphanumeric identifer.)^ ^The values of these 2649** parameters (also called "host parameter names" or "SQL parameters") 2650** can be set using the sqlite3_bind_*() routines defined here. 2651** 2652** ^The first argument to the sqlite3_bind_*() routines is always 2653** a pointer to the [sqlite3_stmt] object returned from 2654** [sqlite3_prepare_v2()] or its variants. 2655** 2656** ^The second argument is the index of the SQL parameter to be set. 2657** ^The leftmost SQL parameter has an index of 1. ^When the same named 2658** SQL parameter is used more than once, second and subsequent 2659** occurrences have the same index as the first occurrence. 2660** ^The index for named parameters can be looked up using the 2661** [sqlite3_bind_parameter_index()] API if desired. ^The index 2662** for "?NNN" parameters is the value of NNN. 2663** ^The NNN value must be between 1 and the [sqlite3_limit()] 2664** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 2665** 2666** ^The third argument is the value to bind to the parameter. 2667** 2668** ^(In those routines that have a fourth argument, its value is the 2669** number of bytes in the parameter. To be clear: the value is the 2670** number of <u>bytes</u> in the value, not the number of characters.)^ 2671** ^If the fourth parameter is negative, the length of the string is 2672** the number of bytes up to the first zero terminator. 2673** 2674** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 2675** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 2676** string after SQLite has finished with it. ^If the fifth argument is 2677** the special value [SQLITE_STATIC], then SQLite assumes that the 2678** information is in static, unmanaged space and does not need to be freed. 2679** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 2680** SQLite makes its own private copy of the data immediately, before 2681** the sqlite3_bind_*() routine returns. 2682** 2683** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 2684** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 2685** (just an integer to hold its size) while it is being processed. 2686** Zeroblobs are intended to serve as placeholders for BLOBs whose 2687** content is later written using 2688** [sqlite3_blob_open | incremental BLOB I/O] routines. 2689** ^A negative value for the zeroblob results in a zero-length BLOB. 2690** 2691** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 2692** for the [prepared statement] or with a prepared statement for which 2693** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 2694** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 2695** routine is passed a [prepared statement] that has been finalized, the 2696** result is undefined and probably harmful. 2697** 2698** ^Bindings are not cleared by the [sqlite3_reset()] routine. 2699** ^Unbound parameters are interpreted as NULL. 2700** 2701** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 2702** [error code] if anything goes wrong. 2703** ^[SQLITE_RANGE] is returned if the parameter 2704** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 2705** 2706** See also: [sqlite3_bind_parameter_count()], 2707** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 2708*/ 2709int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 2710int sqlite3_bind_double(sqlite3_stmt*, int, double); 2711int sqlite3_bind_int(sqlite3_stmt*, int, int); 2712int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 2713int sqlite3_bind_null(sqlite3_stmt*, int); 2714int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 2715int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 2716int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 2717int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 2718 2719/* 2720** CAPI3REF: Number Of SQL Parameters 2721** 2722** ^This routine can be used to find the number of [SQL parameters] 2723** in a [prepared statement]. SQL parameters are tokens of the 2724** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 2725** placeholders for values that are [sqlite3_bind_blob | bound] 2726** to the parameters at a later time. 2727** 2728** ^(This routine actually returns the index of the largest (rightmost) 2729** parameter. For all forms except ?NNN, this will correspond to the 2730** number of unique parameters. If parameters of the ?NNN form are used, 2731** there may be gaps in the list.)^ 2732** 2733** See also: [sqlite3_bind_blob|sqlite3_bind()], 2734** [sqlite3_bind_parameter_name()], and 2735** [sqlite3_bind_parameter_index()]. 2736*/ 2737int sqlite3_bind_parameter_count(sqlite3_stmt*); 2738 2739/* 2740** CAPI3REF: Name Of A Host Parameter 2741** 2742** ^The sqlite3_bind_parameter_name(P,N) interface returns 2743** the name of the N-th [SQL parameter] in the [prepared statement] P. 2744** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 2745** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 2746** respectively. 2747** In other words, the initial ":" or "$" or "@" or "?" 2748** is included as part of the name.)^ 2749** ^Parameters of the form "?" without a following integer have no name 2750** and are referred to as "nameless" or "anonymous parameters". 2751** 2752** ^The first host parameter has an index of 1, not 0. 2753** 2754** ^If the value N is out of range or if the N-th parameter is 2755** nameless, then NULL is returned. ^The returned string is 2756** always in UTF-8 encoding even if the named parameter was 2757** originally specified as UTF-16 in [sqlite3_prepare16()] or 2758** [sqlite3_prepare16_v2()]. 2759** 2760** See also: [sqlite3_bind_blob|sqlite3_bind()], 2761** [sqlite3_bind_parameter_count()], and 2762** [sqlite3_bind_parameter_index()]. 2763*/ 2764const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 2765 2766/* 2767** CAPI3REF: Index Of A Parameter With A Given Name 2768** 2769** ^Return the index of an SQL parameter given its name. ^The 2770** index value returned is suitable for use as the second 2771** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 2772** is returned if no matching parameter is found. ^The parameter 2773** name must be given in UTF-8 even if the original statement 2774** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 2775** 2776** See also: [sqlite3_bind_blob|sqlite3_bind()], 2777** [sqlite3_bind_parameter_count()], and 2778** [sqlite3_bind_parameter_index()]. 2779*/ 2780int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 2781 2782/* 2783** CAPI3REF: Reset All Bindings On A Prepared Statement 2784** 2785** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 2786** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 2787** ^Use this routine to reset all host parameters to NULL. 2788*/ 2789int sqlite3_clear_bindings(sqlite3_stmt*); 2790 2791/* 2792** CAPI3REF: Number Of Columns In A Result Set 2793** 2794** ^Return the number of columns in the result set returned by the 2795** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 2796** statement that does not return data (for example an [UPDATE]). 2797*/ 2798int sqlite3_column_count(sqlite3_stmt *pStmt); 2799 2800/* 2801** CAPI3REF: Column Names In A Result Set 2802** 2803** ^These routines return the name assigned to a particular column 2804** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 2805** interface returns a pointer to a zero-terminated UTF-8 string 2806** and sqlite3_column_name16() returns a pointer to a zero-terminated 2807** UTF-16 string. ^The first parameter is the [prepared statement] 2808** that implements the [SELECT] statement. ^The second parameter is the 2809** column number. ^The leftmost column is number 0. 2810** 2811** ^The returned string pointer is valid until either the [prepared statement] 2812** is destroyed by [sqlite3_finalize()] or until the next call to 2813** sqlite3_column_name() or sqlite3_column_name16() on the same column. 2814** 2815** ^If sqlite3_malloc() fails during the processing of either routine 2816** (for example during a conversion from UTF-8 to UTF-16) then a 2817** NULL pointer is returned. 2818** 2819** ^The name of a result column is the value of the "AS" clause for 2820** that column, if there is an AS clause. If there is no AS clause 2821** then the name of the column is unspecified and may change from 2822** one release of SQLite to the next. 2823*/ 2824const char *sqlite3_column_name(sqlite3_stmt*, int N); 2825const void *sqlite3_column_name16(sqlite3_stmt*, int N); 2826 2827/* 2828** CAPI3REF: Source Of Data In A Query Result 2829** 2830** ^These routines provide a means to determine the database, table, and 2831** table column that is the origin of a particular result column in 2832** [SELECT] statement. 2833** ^The name of the database or table or column can be returned as 2834** either a UTF-8 or UTF-16 string. ^The _database_ routines return 2835** the database name, the _table_ routines return the table name, and 2836** the origin_ routines return the column name. 2837** ^The returned string is valid until the [prepared statement] is destroyed 2838** using [sqlite3_finalize()] or until the same information is requested 2839** again in a different encoding. 2840** 2841** ^The names returned are the original un-aliased names of the 2842** database, table, and column. 2843** 2844** ^The first argument to these interfaces is a [prepared statement]. 2845** ^These functions return information about the Nth result column returned by 2846** the statement, where N is the second function argument. 2847** ^The left-most column is column 0 for these routines. 2848** 2849** ^If the Nth column returned by the statement is an expression or 2850** subquery and is not a column value, then all of these functions return 2851** NULL. ^These routine might also return NULL if a memory allocation error 2852** occurs. ^Otherwise, they return the name of the attached database, table, 2853** or column that query result column was extracted from. 2854** 2855** ^As with all other SQLite APIs, those whose names end with "16" return 2856** UTF-16 encoded strings and the other functions return UTF-8. 2857** 2858** ^These APIs are only available if the library was compiled with the 2859** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 2860** 2861** If two or more threads call one or more of these routines against the same 2862** prepared statement and column at the same time then the results are 2863** undefined. 2864** 2865** If two or more threads call one or more 2866** [sqlite3_column_database_name | column metadata interfaces] 2867** for the same [prepared statement] and result column 2868** at the same time then the results are undefined. 2869*/ 2870const char *sqlite3_column_database_name(sqlite3_stmt*,int); 2871const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 2872const char *sqlite3_column_table_name(sqlite3_stmt*,int); 2873const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 2874const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 2875const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 2876 2877/* 2878** CAPI3REF: Declared Datatype Of A Query Result 2879** 2880** ^(The first parameter is a [prepared statement]. 2881** If this statement is a [SELECT] statement and the Nth column of the 2882** returned result set of that [SELECT] is a table column (not an 2883** expression or subquery) then the declared type of the table 2884** column is returned.)^ ^If the Nth column of the result set is an 2885** expression or subquery, then a NULL pointer is returned. 2886** ^The returned string is always UTF-8 encoded. 2887** 2888** ^(For example, given the database schema: 2889** 2890** CREATE TABLE t1(c1 VARIANT); 2891** 2892** and the following statement to be compiled: 2893** 2894** SELECT c1 + 1, c1 FROM t1; 2895** 2896** this routine would return the string "VARIANT" for the second result 2897** column (i==1), and a NULL pointer for the first result column (i==0).)^ 2898** 2899** ^SQLite uses dynamic run-time typing. ^So just because a column 2900** is declared to contain a particular type does not mean that the 2901** data stored in that column is of the declared type. SQLite is 2902** strongly typed, but the typing is dynamic not static. ^Type 2903** is associated with individual values, not with the containers 2904** used to hold those values. 2905*/ 2906const char *sqlite3_column_decltype(sqlite3_stmt*,int); 2907const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 2908 2909/* 2910** CAPI3REF: Evaluate An SQL Statement 2911** 2912** After a [prepared statement] has been prepared using either 2913** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 2914** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 2915** must be called one or more times to evaluate the statement. 2916** 2917** The details of the behavior of the sqlite3_step() interface depend 2918** on whether the statement was prepared using the newer "v2" interface 2919** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 2920** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 2921** new "v2" interface is recommended for new applications but the legacy 2922** interface will continue to be supported. 2923** 2924** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 2925** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 2926** ^With the "v2" interface, any of the other [result codes] or 2927** [extended result codes] might be returned as well. 2928** 2929** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 2930** database locks it needs to do its job. ^If the statement is a [COMMIT] 2931** or occurs outside of an explicit transaction, then you can retry the 2932** statement. If the statement is not a [COMMIT] and occurs within a 2933** explicit transaction then you should rollback the transaction before 2934** continuing. 2935** 2936** ^[SQLITE_DONE] means that the statement has finished executing 2937** successfully. sqlite3_step() should not be called again on this virtual 2938** machine without first calling [sqlite3_reset()] to reset the virtual 2939** machine back to its initial state. 2940** 2941** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 2942** is returned each time a new row of data is ready for processing by the 2943** caller. The values may be accessed using the [column access functions]. 2944** sqlite3_step() is called again to retrieve the next row of data. 2945** 2946** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 2947** violation) has occurred. sqlite3_step() should not be called again on 2948** the VM. More information may be found by calling [sqlite3_errmsg()]. 2949** ^With the legacy interface, a more specific error code (for example, 2950** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 2951** can be obtained by calling [sqlite3_reset()] on the 2952** [prepared statement]. ^In the "v2" interface, 2953** the more specific error code is returned directly by sqlite3_step(). 2954** 2955** [SQLITE_MISUSE] means that the this routine was called inappropriately. 2956** Perhaps it was called on a [prepared statement] that has 2957** already been [sqlite3_finalize | finalized] or on one that had 2958** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 2959** be the case that the same database connection is being used by two or 2960** more threads at the same moment in time. 2961** 2962** For all versions of SQLite up to and including 3.6.23.1, it was required 2963** after sqlite3_step() returned anything other than [SQLITE_ROW] that 2964** [sqlite3_reset()] be called before any subsequent invocation of 2965** sqlite3_step(). Failure to invoke [sqlite3_reset()] in this way would 2966** result in an [SQLITE_MISUSE] return from sqlite3_step(). But after 2967** version 3.6.23.1, sqlite3_step() began calling [sqlite3_reset()] 2968** automatically in this circumstance rather than returning [SQLITE_MISUSE]. 2969** 2970** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 2971** API always returns a generic error code, [SQLITE_ERROR], following any 2972** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 2973** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 2974** specific [error codes] that better describes the error. 2975** We admit that this is a goofy design. The problem has been fixed 2976** with the "v2" interface. If you prepare all of your SQL statements 2977** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 2978** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 2979** then the more specific [error codes] are returned directly 2980** by sqlite3_step(). The use of the "v2" interface is recommended. 2981*/ 2982int sqlite3_step(sqlite3_stmt*); 2983 2984/* 2985** CAPI3REF: Number of columns in a result set 2986** 2987** ^The sqlite3_data_count(P) the number of columns in the 2988** of the result set of [prepared statement] P. 2989*/ 2990int sqlite3_data_count(sqlite3_stmt *pStmt); 2991 2992/* 2993** CAPI3REF: Fundamental Datatypes 2994** KEYWORDS: SQLITE_TEXT 2995** 2996** ^(Every value in SQLite has one of five fundamental datatypes: 2997** 2998** <ul> 2999** <li> 64-bit signed integer 3000** <li> 64-bit IEEE floating point number 3001** <li> string 3002** <li> BLOB 3003** <li> NULL 3004** </ul>)^ 3005** 3006** These constants are codes for each of those types. 3007** 3008** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3009** for a completely different meaning. Software that links against both 3010** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3011** SQLITE_TEXT. 3012*/ 3013#define SQLITE_INTEGER 1 3014#define SQLITE_FLOAT 2 3015#define SQLITE_BLOB 4 3016#define SQLITE_NULL 5 3017#ifdef SQLITE_TEXT 3018# undef SQLITE_TEXT 3019#else 3020# define SQLITE_TEXT 3 3021#endif 3022#define SQLITE3_TEXT 3 3023 3024/* 3025** CAPI3REF: Result Values From A Query 3026** KEYWORDS: {column access functions} 3027** 3028** These routines form the "result set" interface. 3029** 3030** ^These routines return information about a single column of the current 3031** result row of a query. ^In every case the first argument is a pointer 3032** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3033** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3034** and the second argument is the index of the column for which information 3035** should be returned. ^The leftmost column of the result set has the index 0. 3036** ^The number of columns in the result can be determined using 3037** [sqlite3_column_count()]. 3038** 3039** If the SQL statement does not currently point to a valid row, or if the 3040** column index is out of range, the result is undefined. 3041** These routines may only be called when the most recent call to 3042** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3043** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3044** If any of these routines are called after [sqlite3_reset()] or 3045** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3046** something other than [SQLITE_ROW], the results are undefined. 3047** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3048** are called from a different thread while any of these routines 3049** are pending, then the results are undefined. 3050** 3051** ^The sqlite3_column_type() routine returns the 3052** [SQLITE_INTEGER | datatype code] for the initial data type 3053** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3054** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3055** returned by sqlite3_column_type() is only meaningful if no type 3056** conversions have occurred as described below. After a type conversion, 3057** the value returned by sqlite3_column_type() is undefined. Future 3058** versions of SQLite may change the behavior of sqlite3_column_type() 3059** following a type conversion. 3060** 3061** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3062** routine returns the number of bytes in that BLOB or string. 3063** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3064** the string to UTF-8 and then returns the number of bytes. 3065** ^If the result is a numeric value then sqlite3_column_bytes() uses 3066** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3067** the number of bytes in that string. 3068** ^The value returned does not include the zero terminator at the end 3069** of the string. ^For clarity: the value returned is the number of 3070** bytes in the string, not the number of characters. 3071** 3072** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3073** even empty strings, are always zero terminated. ^The return 3074** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary 3075** pointer, possibly even a NULL pointer. 3076** 3077** ^The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes() 3078** but leaves the result in UTF-16 in native byte order instead of UTF-8. 3079** ^The zero terminator is not included in this count. 3080** 3081** ^The object returned by [sqlite3_column_value()] is an 3082** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3083** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3084** If the [unprotected sqlite3_value] object returned by 3085** [sqlite3_column_value()] is used in any other way, including calls 3086** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3087** or [sqlite3_value_bytes()], then the behavior is undefined. 3088** 3089** These routines attempt to convert the value where appropriate. ^For 3090** example, if the internal representation is FLOAT and a text result 3091** is requested, [sqlite3_snprintf()] is used internally to perform the 3092** conversion automatically. ^(The following table details the conversions 3093** that are applied: 3094** 3095** <blockquote> 3096** <table border="1"> 3097** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3098** 3099** <tr><td> NULL <td> INTEGER <td> Result is 0 3100** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3101** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3102** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3103** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3104** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3105** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3106** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3107** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3108** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3109** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3110** <tr><td> TEXT <td> FLOAT <td> Use atof() 3111** <tr><td> TEXT <td> BLOB <td> No change 3112** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3113** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3114** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3115** </table> 3116** </blockquote>)^ 3117** 3118** The table above makes reference to standard C library functions atoi() 3119** and atof(). SQLite does not really use these functions. It has its 3120** own equivalent internal routines. The atoi() and atof() names are 3121** used in the table for brevity and because they are familiar to most 3122** C programmers. 3123** 3124** ^Note that when type conversions occur, pointers returned by prior 3125** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3126** sqlite3_column_text16() may be invalidated. 3127** ^(Type conversions and pointer invalidations might occur 3128** in the following cases: 3129** 3130** <ul> 3131** <li> The initial content is a BLOB and sqlite3_column_text() or 3132** sqlite3_column_text16() is called. A zero-terminator might 3133** need to be added to the string.</li> 3134** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3135** sqlite3_column_text16() is called. The content must be converted 3136** to UTF-16.</li> 3137** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3138** sqlite3_column_text() is called. The content must be converted 3139** to UTF-8.</li> 3140** </ul>)^ 3141** 3142** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3143** not invalidate a prior pointer, though of course the content of the buffer 3144** that the prior pointer points to will have been modified. Other kinds 3145** of conversion are done in place when it is possible, but sometimes they 3146** are not possible and in those cases prior pointers are invalidated. 3147** 3148** ^(The safest and easiest to remember policy is to invoke these routines 3149** in one of the following ways: 3150** 3151** <ul> 3152** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3153** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3154** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3155** </ul>)^ 3156** 3157** In other words, you should call sqlite3_column_text(), 3158** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3159** into the desired format, then invoke sqlite3_column_bytes() or 3160** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3161** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3162** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3163** with calls to sqlite3_column_bytes(). 3164** 3165** ^The pointers returned are valid until a type conversion occurs as 3166** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3167** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3168** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3169** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3170** [sqlite3_free()]. 3171** 3172** ^(If a memory allocation error occurs during the evaluation of any 3173** of these routines, a default value is returned. The default value 3174** is either the integer 0, the floating point number 0.0, or a NULL 3175** pointer. Subsequent calls to [sqlite3_errcode()] will return 3176** [SQLITE_NOMEM].)^ 3177*/ 3178const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3179int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3180int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3181double sqlite3_column_double(sqlite3_stmt*, int iCol); 3182int sqlite3_column_int(sqlite3_stmt*, int iCol); 3183sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3184const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3185const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3186int sqlite3_column_type(sqlite3_stmt*, int iCol); 3187sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3188 3189/* 3190** CAPI3REF: Destroy A Prepared Statement Object 3191** 3192** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3193** ^If the statement was executed successfully or not executed at all, then 3194** SQLITE_OK is returned. ^If execution of the statement failed then an 3195** [error code] or [extended error code] is returned. 3196** 3197** ^This routine can be called at any point during the execution of the 3198** [prepared statement]. ^If the virtual machine has not 3199** completed execution when this routine is called, that is like 3200** encountering an error or an [sqlite3_interrupt | interrupt]. 3201** ^Incomplete updates may be rolled back and transactions canceled, 3202** depending on the circumstances, and the 3203** [error code] returned will be [SQLITE_ABORT]. 3204*/ 3205int sqlite3_finalize(sqlite3_stmt *pStmt); 3206 3207/* 3208** CAPI3REF: Reset A Prepared Statement Object 3209** 3210** The sqlite3_reset() function is called to reset a [prepared statement] 3211** object back to its initial state, ready to be re-executed. 3212** ^Any SQL statement variables that had values bound to them using 3213** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3214** Use [sqlite3_clear_bindings()] to reset the bindings. 3215** 3216** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3217** back to the beginning of its program. 3218** 3219** ^If the most recent call to [sqlite3_step(S)] for the 3220** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3221** or if [sqlite3_step(S)] has never before been called on S, 3222** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3223** 3224** ^If the most recent call to [sqlite3_step(S)] for the 3225** [prepared statement] S indicated an error, then 3226** [sqlite3_reset(S)] returns an appropriate [error code]. 3227** 3228** ^The [sqlite3_reset(S)] interface does not change the values 3229** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3230*/ 3231int sqlite3_reset(sqlite3_stmt *pStmt); 3232 3233/* 3234** CAPI3REF: Create Or Redefine SQL Functions 3235** KEYWORDS: {function creation routines} 3236** KEYWORDS: {application-defined SQL function} 3237** KEYWORDS: {application-defined SQL functions} 3238** 3239** ^These two functions (collectively known as "function creation routines") 3240** are used to add SQL functions or aggregates or to redefine the behavior 3241** of existing SQL functions or aggregates. The only difference between the 3242** two is that the second parameter, the name of the (scalar) function or 3243** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16 3244** for sqlite3_create_function16(). 3245** 3246** ^The first parameter is the [database connection] to which the SQL 3247** function is to be added. ^If an application uses more than one database 3248** connection then application-defined SQL functions must be added 3249** to each database connection separately. 3250** 3251** The second parameter is the name of the SQL function to be created or 3252** redefined. ^The length of the name is limited to 255 bytes, exclusive of 3253** the zero-terminator. Note that the name length limit is in bytes, not 3254** characters. ^Any attempt to create a function with a longer name 3255** will result in [SQLITE_ERROR] being returned. 3256** 3257** ^The third parameter (nArg) 3258** is the number of arguments that the SQL function or 3259** aggregate takes. ^If this parameter is -1, then the SQL function or 3260** aggregate may take any number of arguments between 0 and the limit 3261** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3262** parameter is less than -1 or greater than 127 then the behavior is 3263** undefined. 3264** 3265** The fourth parameter, eTextRep, specifies what 3266** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3267** its parameters. Any SQL function implementation should be able to work 3268** work with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3269** more efficient with one encoding than another. ^An application may 3270** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3271** times with the same function but with different values of eTextRep. 3272** ^When multiple implementations of the same function are available, SQLite 3273** will pick the one that involves the least amount of data conversion. 3274** If there is only a single implementation which does not care what text 3275** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3276** 3277** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3278** function can gain access to this pointer using [sqlite3_user_data()].)^ 3279** 3280** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are 3281** pointers to C-language functions that implement the SQL function or 3282** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3283** callback only; NULL pointers should be passed as the xStep and xFinal 3284** parameters. ^An aggregate SQL function requires an implementation of xStep 3285** and xFinal and NULL should be passed for xFunc. ^To delete an existing 3286** SQL function or aggregate, pass NULL for all three function callbacks. 3287** 3288** ^It is permitted to register multiple implementations of the same 3289** functions with the same name but with either differing numbers of 3290** arguments or differing preferred text encodings. ^SQLite will use 3291** the implementation that most closely matches the way in which the 3292** SQL function is used. ^A function implementation with a non-negative 3293** nArg parameter is a better match than a function implementation with 3294** a negative nArg. ^A function where the preferred text encoding 3295** matches the database encoding is a better 3296** match than a function where the encoding is different. 3297** ^A function where the encoding difference is between UTF16le and UTF16be 3298** is a closer match than a function where the encoding difference is 3299** between UTF8 and UTF16. 3300** 3301** ^Built-in functions may be overloaded by new application-defined functions. 3302** ^The first application-defined function with a given name overrides all 3303** built-in functions in the same [database connection] with the same name. 3304** ^Subsequent application-defined functions of the same name only override 3305** prior application-defined functions that are an exact match for the 3306** number of parameters and preferred encoding. 3307** 3308** ^An application-defined function is permitted to call other 3309** SQLite interfaces. However, such calls must not 3310** close the database connection nor finalize or reset the prepared 3311** statement in which the function is running. 3312*/ 3313int sqlite3_create_function( 3314 sqlite3 *db, 3315 const char *zFunctionName, 3316 int nArg, 3317 int eTextRep, 3318 void *pApp, 3319 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3320 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3321 void (*xFinal)(sqlite3_context*) 3322); 3323int sqlite3_create_function16( 3324 sqlite3 *db, 3325 const void *zFunctionName, 3326 int nArg, 3327 int eTextRep, 3328 void *pApp, 3329 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3330 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3331 void (*xFinal)(sqlite3_context*) 3332); 3333 3334/* 3335** CAPI3REF: Text Encodings 3336** 3337** These constant define integer codes that represent the various 3338** text encodings supported by SQLite. 3339*/ 3340#define SQLITE_UTF8 1 3341#define SQLITE_UTF16LE 2 3342#define SQLITE_UTF16BE 3 3343#define SQLITE_UTF16 4 /* Use native byte order */ 3344#define SQLITE_ANY 5 /* sqlite3_create_function only */ 3345#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3346 3347/* 3348** CAPI3REF: Deprecated Functions 3349** DEPRECATED 3350** 3351** These functions are [deprecated]. In order to maintain 3352** backwards compatibility with older code, these functions continue 3353** to be supported. However, new applications should avoid 3354** the use of these functions. To help encourage people to avoid 3355** using these functions, we are not going to tell you what they do. 3356*/ 3357#ifndef SQLITE_OMIT_DEPRECATED 3358SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3359SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3360SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3361SQLITE_DEPRECATED int sqlite3_global_recover(void); 3362SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3363SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3364#endif 3365 3366/* 3367** CAPI3REF: Obtaining SQL Function Parameter Values 3368** 3369** The C-language implementation of SQL functions and aggregates uses 3370** this set of interface routines to access the parameter values on 3371** the function or aggregate. 3372** 3373** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3374** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3375** define callbacks that implement the SQL functions and aggregates. 3376** The 4th parameter to these callbacks is an array of pointers to 3377** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3378** each parameter to the SQL function. These routines are used to 3379** extract values from the [sqlite3_value] objects. 3380** 3381** These routines work only with [protected sqlite3_value] objects. 3382** Any attempt to use these routines on an [unprotected sqlite3_value] 3383** object results in undefined behavior. 3384** 3385** ^These routines work just like the corresponding [column access functions] 3386** except that these routines take a single [protected sqlite3_value] object 3387** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3388** 3389** ^The sqlite3_value_text16() interface extracts a UTF-16 string 3390** in the native byte-order of the host machine. ^The 3391** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3392** extract UTF-16 strings as big-endian and little-endian respectively. 3393** 3394** ^(The sqlite3_value_numeric_type() interface attempts to apply 3395** numeric affinity to the value. This means that an attempt is 3396** made to convert the value to an integer or floating point. If 3397** such a conversion is possible without loss of information (in other 3398** words, if the value is a string that looks like a number) 3399** then the conversion is performed. Otherwise no conversion occurs. 3400** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 3401** 3402** Please pay particular attention to the fact that the pointer returned 3403** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3404** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3405** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3406** or [sqlite3_value_text16()]. 3407** 3408** These routines must be called from the same thread as 3409** the SQL function that supplied the [sqlite3_value*] parameters. 3410*/ 3411const void *sqlite3_value_blob(sqlite3_value*); 3412int sqlite3_value_bytes(sqlite3_value*); 3413int sqlite3_value_bytes16(sqlite3_value*); 3414double sqlite3_value_double(sqlite3_value*); 3415int sqlite3_value_int(sqlite3_value*); 3416sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3417const unsigned char *sqlite3_value_text(sqlite3_value*); 3418const void *sqlite3_value_text16(sqlite3_value*); 3419const void *sqlite3_value_text16le(sqlite3_value*); 3420const void *sqlite3_value_text16be(sqlite3_value*); 3421int sqlite3_value_type(sqlite3_value*); 3422int sqlite3_value_numeric_type(sqlite3_value*); 3423 3424/* 3425** CAPI3REF: Obtain Aggregate Function Context 3426** 3427** Implementions of aggregate SQL functions use this 3428** routine to allocate memory for storing their state. 3429** 3430** ^The first time the sqlite3_aggregate_context(C,N) routine is called 3431** for a particular aggregate function, SQLite 3432** allocates N of memory, zeroes out that memory, and returns a pointer 3433** to the new memory. ^On second and subsequent calls to 3434** sqlite3_aggregate_context() for the same aggregate function instance, 3435** the same buffer is returned. Sqlite3_aggregate_context() is normally 3436** called once for each invocation of the xStep callback and then one 3437** last time when the xFinal callback is invoked. ^(When no rows match 3438** an aggregate query, the xStep() callback of the aggregate function 3439** implementation is never called and xFinal() is called exactly once. 3440** In those cases, sqlite3_aggregate_context() might be called for the 3441** first time from within xFinal().)^ 3442** 3443** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is 3444** less than or equal to zero or if a memory allocate error occurs. 3445** 3446** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 3447** determined by the N parameter on first successful call. Changing the 3448** value of N in subsequent call to sqlite3_aggregate_context() within 3449** the same aggregate function instance will not resize the memory 3450** allocation.)^ 3451** 3452** ^SQLite automatically frees the memory allocated by 3453** sqlite3_aggregate_context() when the aggregate query concludes. 3454** 3455** The first parameter must be a copy of the 3456** [sqlite3_context | SQL function context] that is the first parameter 3457** to the xStep or xFinal callback routine that implements the aggregate 3458** function. 3459** 3460** This routine must be called from the same thread in which 3461** the aggregate SQL function is running. 3462*/ 3463void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 3464 3465/* 3466** CAPI3REF: User Data For Functions 3467** 3468** ^The sqlite3_user_data() interface returns a copy of 3469** the pointer that was the pUserData parameter (the 5th parameter) 3470** of the [sqlite3_create_function()] 3471** and [sqlite3_create_function16()] routines that originally 3472** registered the application defined function. 3473** 3474** This routine must be called from the same thread in which 3475** the application-defined function is running. 3476*/ 3477void *sqlite3_user_data(sqlite3_context*); 3478 3479/* 3480** CAPI3REF: Database Connection For Functions 3481** 3482** ^The sqlite3_context_db_handle() interface returns a copy of 3483** the pointer to the [database connection] (the 1st parameter) 3484** of the [sqlite3_create_function()] 3485** and [sqlite3_create_function16()] routines that originally 3486** registered the application defined function. 3487*/ 3488sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 3489 3490/* 3491** CAPI3REF: Function Auxiliary Data 3492** 3493** The following two functions may be used by scalar SQL functions to 3494** associate metadata with argument values. If the same value is passed to 3495** multiple invocations of the same SQL function during query execution, under 3496** some circumstances the associated metadata may be preserved. This may 3497** be used, for example, to add a regular-expression matching scalar 3498** function. The compiled version of the regular expression is stored as 3499** metadata associated with the SQL value passed as the regular expression 3500** pattern. The compiled regular expression can be reused on multiple 3501** invocations of the same function so that the original pattern string 3502** does not need to be recompiled on each invocation. 3503** 3504** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 3505** associated by the sqlite3_set_auxdata() function with the Nth argument 3506** value to the application-defined function. ^If no metadata has been ever 3507** been set for the Nth argument of the function, or if the corresponding 3508** function parameter has changed since the meta-data was set, 3509** then sqlite3_get_auxdata() returns a NULL pointer. 3510** 3511** ^The sqlite3_set_auxdata() interface saves the metadata 3512** pointed to by its 3rd parameter as the metadata for the N-th 3513** argument of the application-defined function. Subsequent 3514** calls to sqlite3_get_auxdata() might return this data, if it has 3515** not been destroyed. 3516** ^If it is not NULL, SQLite will invoke the destructor 3517** function given by the 4th parameter to sqlite3_set_auxdata() on 3518** the metadata when the corresponding function parameter changes 3519** or when the SQL statement completes, whichever comes first. 3520** 3521** SQLite is free to call the destructor and drop metadata on any 3522** parameter of any function at any time. ^The only guarantee is that 3523** the destructor will be called before the metadata is dropped. 3524** 3525** ^(In practice, metadata is preserved between function calls for 3526** expressions that are constant at compile time. This includes literal 3527** values and [parameters].)^ 3528** 3529** These routines must be called from the same thread in which 3530** the SQL function is running. 3531*/ 3532void *sqlite3_get_auxdata(sqlite3_context*, int N); 3533void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 3534 3535 3536/* 3537** CAPI3REF: Constants Defining Special Destructor Behavior 3538** 3539** These are special values for the destructor that is passed in as the 3540** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 3541** argument is SQLITE_STATIC, it means that the content pointer is constant 3542** and will never change. It does not need to be destroyed. ^The 3543** SQLITE_TRANSIENT value means that the content will likely change in 3544** the near future and that SQLite should make its own private copy of 3545** the content before returning. 3546** 3547** The typedef is necessary to work around problems in certain 3548** C++ compilers. See ticket #2191. 3549*/ 3550typedef void (*sqlite3_destructor_type)(void*); 3551#define SQLITE_STATIC ((sqlite3_destructor_type)0) 3552#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 3553 3554/* 3555** CAPI3REF: Setting The Result Of An SQL Function 3556** 3557** These routines are used by the xFunc or xFinal callbacks that 3558** implement SQL functions and aggregates. See 3559** [sqlite3_create_function()] and [sqlite3_create_function16()] 3560** for additional information. 3561** 3562** These functions work very much like the [parameter binding] family of 3563** functions used to bind values to host parameters in prepared statements. 3564** Refer to the [SQL parameter] documentation for additional information. 3565** 3566** ^The sqlite3_result_blob() interface sets the result from 3567** an application-defined function to be the BLOB whose content is pointed 3568** to by the second parameter and which is N bytes long where N is the 3569** third parameter. 3570** 3571** ^The sqlite3_result_zeroblob() interfaces set the result of 3572** the application-defined function to be a BLOB containing all zero 3573** bytes and N bytes in size, where N is the value of the 2nd parameter. 3574** 3575** ^The sqlite3_result_double() interface sets the result from 3576** an application-defined function to be a floating point value specified 3577** by its 2nd argument. 3578** 3579** ^The sqlite3_result_error() and sqlite3_result_error16() functions 3580** cause the implemented SQL function to throw an exception. 3581** ^SQLite uses the string pointed to by the 3582** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 3583** as the text of an error message. ^SQLite interprets the error 3584** message string from sqlite3_result_error() as UTF-8. ^SQLite 3585** interprets the string from sqlite3_result_error16() as UTF-16 in native 3586** byte order. ^If the third parameter to sqlite3_result_error() 3587** or sqlite3_result_error16() is negative then SQLite takes as the error 3588** message all text up through the first zero character. 3589** ^If the third parameter to sqlite3_result_error() or 3590** sqlite3_result_error16() is non-negative then SQLite takes that many 3591** bytes (not characters) from the 2nd parameter as the error message. 3592** ^The sqlite3_result_error() and sqlite3_result_error16() 3593** routines make a private copy of the error message text before 3594** they return. Hence, the calling function can deallocate or 3595** modify the text after they return without harm. 3596** ^The sqlite3_result_error_code() function changes the error code 3597** returned by SQLite as a result of an error in a function. ^By default, 3598** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 3599** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 3600** 3601** ^The sqlite3_result_toobig() interface causes SQLite to throw an error 3602** indicating that a string or BLOB is too long to represent. 3603** 3604** ^The sqlite3_result_nomem() interface causes SQLite to throw an error 3605** indicating that a memory allocation failed. 3606** 3607** ^The sqlite3_result_int() interface sets the return value 3608** of the application-defined function to be the 32-bit signed integer 3609** value given in the 2nd argument. 3610** ^The sqlite3_result_int64() interface sets the return value 3611** of the application-defined function to be the 64-bit signed integer 3612** value given in the 2nd argument. 3613** 3614** ^The sqlite3_result_null() interface sets the return value 3615** of the application-defined function to be NULL. 3616** 3617** ^The sqlite3_result_text(), sqlite3_result_text16(), 3618** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 3619** set the return value of the application-defined function to be 3620** a text string which is represented as UTF-8, UTF-16 native byte order, 3621** UTF-16 little endian, or UTF-16 big endian, respectively. 3622** ^SQLite takes the text result from the application from 3623** the 2nd parameter of the sqlite3_result_text* interfaces. 3624** ^If the 3rd parameter to the sqlite3_result_text* interfaces 3625** is negative, then SQLite takes result text from the 2nd parameter 3626** through the first zero character. 3627** ^If the 3rd parameter to the sqlite3_result_text* interfaces 3628** is non-negative, then as many bytes (not characters) of the text 3629** pointed to by the 2nd parameter are taken as the application-defined 3630** function result. 3631** ^If the 4th parameter to the sqlite3_result_text* interfaces 3632** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 3633** function as the destructor on the text or BLOB result when it has 3634** finished using that result. 3635** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 3636** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 3637** assumes that the text or BLOB result is in constant space and does not 3638** copy the content of the parameter nor call a destructor on the content 3639** when it has finished using that result. 3640** ^If the 4th parameter to the sqlite3_result_text* interfaces 3641** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 3642** then SQLite makes a copy of the result into space obtained from 3643** from [sqlite3_malloc()] before it returns. 3644** 3645** ^The sqlite3_result_value() interface sets the result of 3646** the application-defined function to be a copy the 3647** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 3648** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 3649** so that the [sqlite3_value] specified in the parameter may change or 3650** be deallocated after sqlite3_result_value() returns without harm. 3651** ^A [protected sqlite3_value] object may always be used where an 3652** [unprotected sqlite3_value] object is required, so either 3653** kind of [sqlite3_value] object can be used with this interface. 3654** 3655** If these routines are called from within the different thread 3656** than the one containing the application-defined function that received 3657** the [sqlite3_context] pointer, the results are undefined. 3658*/ 3659void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 3660void sqlite3_result_double(sqlite3_context*, double); 3661void sqlite3_result_error(sqlite3_context*, const char*, int); 3662void sqlite3_result_error16(sqlite3_context*, const void*, int); 3663void sqlite3_result_error_toobig(sqlite3_context*); 3664void sqlite3_result_error_nomem(sqlite3_context*); 3665void sqlite3_result_error_code(sqlite3_context*, int); 3666void sqlite3_result_int(sqlite3_context*, int); 3667void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 3668void sqlite3_result_null(sqlite3_context*); 3669void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 3670void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 3671void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 3672void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 3673void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 3674void sqlite3_result_zeroblob(sqlite3_context*, int n); 3675 3676/* 3677** CAPI3REF: Define New Collating Sequences 3678** 3679** These functions are used to add new collation sequences to the 3680** [database connection] specified as the first argument. 3681** 3682** ^The name of the new collation sequence is specified as a UTF-8 string 3683** for sqlite3_create_collation() and sqlite3_create_collation_v2() 3684** and a UTF-16 string for sqlite3_create_collation16(). ^In all cases 3685** the name is passed as the second function argument. 3686** 3687** ^The third argument may be one of the constants [SQLITE_UTF8], 3688** [SQLITE_UTF16LE], or [SQLITE_UTF16BE], indicating that the user-supplied 3689** routine expects to be passed pointers to strings encoded using UTF-8, 3690** UTF-16 little-endian, or UTF-16 big-endian, respectively. ^The 3691** third argument might also be [SQLITE_UTF16] to indicate that the routine 3692** expects pointers to be UTF-16 strings in the native byte order, or the 3693** argument can be [SQLITE_UTF16_ALIGNED] if the 3694** the routine expects pointers to 16-bit word aligned strings 3695** of UTF-16 in the native byte order. 3696** 3697** A pointer to the user supplied routine must be passed as the fifth 3698** argument. ^If it is NULL, this is the same as deleting the collation 3699** sequence (so that SQLite cannot call it anymore). 3700** ^Each time the application supplied function is invoked, it is passed 3701** as its first parameter a copy of the void* passed as the fourth argument 3702** to sqlite3_create_collation() or sqlite3_create_collation16(). 3703** 3704** ^The remaining arguments to the application-supplied routine are two strings, 3705** each represented by a (length, data) pair and encoded in the encoding 3706** that was passed as the third argument when the collation sequence was 3707** registered. The application defined collation routine should 3708** return negative, zero or positive if the first string is less than, 3709** equal to, or greater than the second string. i.e. (STRING1 - STRING2). 3710** 3711** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 3712** except that it takes an extra argument which is a destructor for 3713** the collation. ^The destructor is called when the collation is 3714** destroyed and is passed a copy of the fourth parameter void* pointer 3715** of the sqlite3_create_collation_v2(). 3716** ^Collations are destroyed when they are overridden by later calls to the 3717** collation creation functions or when the [database connection] is closed 3718** using [sqlite3_close()]. 3719** 3720** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 3721*/ 3722int sqlite3_create_collation( 3723 sqlite3*, 3724 const char *zName, 3725 int eTextRep, 3726 void*, 3727 int(*xCompare)(void*,int,const void*,int,const void*) 3728); 3729int sqlite3_create_collation_v2( 3730 sqlite3*, 3731 const char *zName, 3732 int eTextRep, 3733 void*, 3734 int(*xCompare)(void*,int,const void*,int,const void*), 3735 void(*xDestroy)(void*) 3736); 3737int sqlite3_create_collation16( 3738 sqlite3*, 3739 const void *zName, 3740 int eTextRep, 3741 void*, 3742 int(*xCompare)(void*,int,const void*,int,const void*) 3743); 3744 3745/* 3746** CAPI3REF: Collation Needed Callbacks 3747** 3748** ^To avoid having to register all collation sequences before a database 3749** can be used, a single callback function may be registered with the 3750** [database connection] to be invoked whenever an undefined collation 3751** sequence is required. 3752** 3753** ^If the function is registered using the sqlite3_collation_needed() API, 3754** then it is passed the names of undefined collation sequences as strings 3755** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 3756** the names are passed as UTF-16 in machine native byte order. 3757** ^A call to either function replaces the existing collation-needed callback. 3758** 3759** ^(When the callback is invoked, the first argument passed is a copy 3760** of the second argument to sqlite3_collation_needed() or 3761** sqlite3_collation_needed16(). The second argument is the database 3762** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 3763** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 3764** sequence function required. The fourth parameter is the name of the 3765** required collation sequence.)^ 3766** 3767** The callback function should register the desired collation using 3768** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 3769** [sqlite3_create_collation_v2()]. 3770*/ 3771int sqlite3_collation_needed( 3772 sqlite3*, 3773 void*, 3774 void(*)(void*,sqlite3*,int eTextRep,const char*) 3775); 3776int sqlite3_collation_needed16( 3777 sqlite3*, 3778 void*, 3779 void(*)(void*,sqlite3*,int eTextRep,const void*) 3780); 3781 3782#ifdef SQLITE_HAS_CODEC 3783/* 3784** Specify the key for an encrypted database. This routine should be 3785** called right after sqlite3_open(). 3786** 3787** The code to implement this API is not available in the public release 3788** of SQLite. 3789*/ 3790int sqlite3_key( 3791 sqlite3 *db, /* Database to be rekeyed */ 3792 const void *pKey, int nKey /* The key */ 3793); 3794 3795/* 3796** Change the key on an open database. If the current database is not 3797** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 3798** database is decrypted. 3799** 3800** The code to implement this API is not available in the public release 3801** of SQLite. 3802*/ 3803int sqlite3_rekey( 3804 sqlite3 *db, /* Database to be rekeyed */ 3805 const void *pKey, int nKey /* The new key */ 3806); 3807 3808/* 3809** Specify the activation key for a SEE database. Unless 3810** activated, none of the SEE routines will work. 3811*/ 3812void sqlite3_activate_see( 3813 const char *zPassPhrase /* Activation phrase */ 3814); 3815#endif 3816 3817#ifdef SQLITE_ENABLE_CEROD 3818/* 3819** Specify the activation key for a CEROD database. Unless 3820** activated, none of the CEROD routines will work. 3821*/ 3822void sqlite3_activate_cerod( 3823 const char *zPassPhrase /* Activation phrase */ 3824); 3825#endif 3826 3827/* 3828** CAPI3REF: Suspend Execution For A Short Time 3829** 3830** ^The sqlite3_sleep() function causes the current thread to suspend execution 3831** for at least a number of milliseconds specified in its parameter. 3832** 3833** ^If the operating system does not support sleep requests with 3834** millisecond time resolution, then the time will be rounded up to 3835** the nearest second. ^The number of milliseconds of sleep actually 3836** requested from the operating system is returned. 3837** 3838** ^SQLite implements this interface by calling the xSleep() 3839** method of the default [sqlite3_vfs] object. 3840*/ 3841int sqlite3_sleep(int); 3842 3843/* 3844** CAPI3REF: Name Of The Folder Holding Temporary Files 3845** 3846** ^(If this global variable is made to point to a string which is 3847** the name of a folder (a.k.a. directory), then all temporary files 3848** created by SQLite when using a built-in [sqlite3_vfs | VFS] 3849** will be placed in that directory.)^ ^If this variable 3850** is a NULL pointer, then SQLite performs a search for an appropriate 3851** temporary file directory. 3852** 3853** It is not safe to read or modify this variable in more than one 3854** thread at a time. It is not safe to read or modify this variable 3855** if a [database connection] is being used at the same time in a separate 3856** thread. 3857** It is intended that this variable be set once 3858** as part of process initialization and before any SQLite interface 3859** routines have been called and that this variable remain unchanged 3860** thereafter. 3861** 3862** ^The [temp_store_directory pragma] may modify this variable and cause 3863** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 3864** the [temp_store_directory pragma] always assumes that any string 3865** that this variable points to is held in memory obtained from 3866** [sqlite3_malloc] and the pragma may attempt to free that memory 3867** using [sqlite3_free]. 3868** Hence, if this variable is modified directly, either it should be 3869** made NULL or made to point to memory obtained from [sqlite3_malloc] 3870** or else the use of the [temp_store_directory pragma] should be avoided. 3871*/ 3872SQLITE_EXTERN char *sqlite3_temp_directory; 3873 3874/* 3875** CAPI3REF: Test For Auto-Commit Mode 3876** KEYWORDS: {autocommit mode} 3877** 3878** ^The sqlite3_get_autocommit() interface returns non-zero or 3879** zero if the given database connection is or is not in autocommit mode, 3880** respectively. ^Autocommit mode is on by default. 3881** ^Autocommit mode is disabled by a [BEGIN] statement. 3882** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 3883** 3884** If certain kinds of errors occur on a statement within a multi-statement 3885** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 3886** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 3887** transaction might be rolled back automatically. The only way to 3888** find out whether SQLite automatically rolled back the transaction after 3889** an error is to use this function. 3890** 3891** If another thread changes the autocommit status of the database 3892** connection while this routine is running, then the return value 3893** is undefined. 3894*/ 3895int sqlite3_get_autocommit(sqlite3*); 3896 3897/* 3898** CAPI3REF: Find The Database Handle Of A Prepared Statement 3899** 3900** ^The sqlite3_db_handle interface returns the [database connection] handle 3901** to which a [prepared statement] belongs. ^The [database connection] 3902** returned by sqlite3_db_handle is the same [database connection] 3903** that was the first argument 3904** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 3905** create the statement in the first place. 3906*/ 3907sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 3908 3909/* 3910** CAPI3REF: Find the next prepared statement 3911** 3912** ^This interface returns a pointer to the next [prepared statement] after 3913** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 3914** then this interface returns a pointer to the first prepared statement 3915** associated with the database connection pDb. ^If no prepared statement 3916** satisfies the conditions of this routine, it returns NULL. 3917** 3918** The [database connection] pointer D in a call to 3919** [sqlite3_next_stmt(D,S)] must refer to an open database 3920** connection and in particular must not be a NULL pointer. 3921*/ 3922sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 3923 3924/* 3925** CAPI3REF: Commit And Rollback Notification Callbacks 3926** 3927** ^The sqlite3_commit_hook() interface registers a callback 3928** function to be invoked whenever a transaction is [COMMIT | committed]. 3929** ^Any callback set by a previous call to sqlite3_commit_hook() 3930** for the same database connection is overridden. 3931** ^The sqlite3_rollback_hook() interface registers a callback 3932** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 3933** ^Any callback set by a previous call to sqlite3_rollback_hook() 3934** for the same database connection is overridden. 3935** ^The pArg argument is passed through to the callback. 3936** ^If the callback on a commit hook function returns non-zero, 3937** then the commit is converted into a rollback. 3938** 3939** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 3940** return the P argument from the previous call of the same function 3941** on the same [database connection] D, or NULL for 3942** the first call for each function on D. 3943** 3944** The callback implementation must not do anything that will modify 3945** the database connection that invoked the callback. Any actions 3946** to modify the database connection must be deferred until after the 3947** completion of the [sqlite3_step()] call that triggered the commit 3948** or rollback hook in the first place. 3949** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3950** database connections for the meaning of "modify" in this paragraph. 3951** 3952** ^Registering a NULL function disables the callback. 3953** 3954** ^When the commit hook callback routine returns zero, the [COMMIT] 3955** operation is allowed to continue normally. ^If the commit hook 3956** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 3957** ^The rollback hook is invoked on a rollback that results from a commit 3958** hook returning non-zero, just as it would be with any other rollback. 3959** 3960** ^For the purposes of this API, a transaction is said to have been 3961** rolled back if an explicit "ROLLBACK" statement is executed, or 3962** an error or constraint causes an implicit rollback to occur. 3963** ^The rollback callback is not invoked if a transaction is 3964** automatically rolled back because the database connection is closed. 3965** 3966** See also the [sqlite3_update_hook()] interface. 3967*/ 3968void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 3969void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 3970 3971/* 3972** CAPI3REF: Data Change Notification Callbacks 3973** 3974** ^The sqlite3_update_hook() interface registers a callback function 3975** with the [database connection] identified by the first argument 3976** to be invoked whenever a row is updated, inserted or deleted. 3977** ^Any callback set by a previous call to this function 3978** for the same database connection is overridden. 3979** 3980** ^The second argument is a pointer to the function to invoke when a 3981** row is updated, inserted or deleted. 3982** ^The first argument to the callback is a copy of the third argument 3983** to sqlite3_update_hook(). 3984** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 3985** or [SQLITE_UPDATE], depending on the operation that caused the callback 3986** to be invoked. 3987** ^The third and fourth arguments to the callback contain pointers to the 3988** database and table name containing the affected row. 3989** ^The final callback parameter is the [rowid] of the row. 3990** ^In the case of an update, this is the [rowid] after the update takes place. 3991** 3992** ^(The update hook is not invoked when internal system tables are 3993** modified (i.e. sqlite_master and sqlite_sequence).)^ 3994** 3995** ^In the current implementation, the update hook 3996** is not invoked when duplication rows are deleted because of an 3997** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 3998** invoked when rows are deleted using the [truncate optimization]. 3999** The exceptions defined in this paragraph might change in a future 4000** release of SQLite. 4001** 4002** The update hook implementation must not do anything that will modify 4003** the database connection that invoked the update hook. Any actions 4004** to modify the database connection must be deferred until after the 4005** completion of the [sqlite3_step()] call that triggered the update hook. 4006** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4007** database connections for the meaning of "modify" in this paragraph. 4008** 4009** ^The sqlite3_update_hook(D,C,P) function 4010** returns the P argument from the previous call 4011** on the same [database connection] D, or NULL for 4012** the first call on D. 4013** 4014** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4015** interfaces. 4016*/ 4017void *sqlite3_update_hook( 4018 sqlite3*, 4019 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4020 void* 4021); 4022 4023/* 4024** CAPI3REF: Enable Or Disable Shared Pager Cache 4025** KEYWORDS: {shared cache} 4026** 4027** ^(This routine enables or disables the sharing of the database cache 4028** and schema data structures between [database connection | connections] 4029** to the same database. Sharing is enabled if the argument is true 4030** and disabled if the argument is false.)^ 4031** 4032** ^Cache sharing is enabled and disabled for an entire process. 4033** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4034** sharing was enabled or disabled for each thread separately. 4035** 4036** ^(The cache sharing mode set by this interface effects all subsequent 4037** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4038** Existing database connections continue use the sharing mode 4039** that was in effect at the time they were opened.)^ 4040** 4041** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4042** successfully. An [error code] is returned otherwise.)^ 4043** 4044** ^Shared cache is disabled by default. But this might change in 4045** future releases of SQLite. Applications that care about shared 4046** cache setting should set it explicitly. 4047** 4048** See Also: [SQLite Shared-Cache Mode] 4049*/ 4050int sqlite3_enable_shared_cache(int); 4051 4052/* 4053** CAPI3REF: Attempt To Free Heap Memory 4054** 4055** ^The sqlite3_release_memory() interface attempts to free N bytes 4056** of heap memory by deallocating non-essential memory allocations 4057** held by the database library. Memory used to cache database 4058** pages to improve performance is an example of non-essential memory. 4059** ^sqlite3_release_memory() returns the number of bytes actually freed, 4060** which might be more or less than the amount requested. 4061*/ 4062int sqlite3_release_memory(int); 4063 4064/* 4065** CAPI3REF: Impose A Limit On Heap Size 4066** 4067** ^The sqlite3_soft_heap_limit() interface places a "soft" limit 4068** on the amount of heap memory that may be allocated by SQLite. 4069** ^If an internal allocation is requested that would exceed the 4070** soft heap limit, [sqlite3_release_memory()] is invoked one or 4071** more times to free up some space before the allocation is performed. 4072** 4073** ^The limit is called "soft" because if [sqlite3_release_memory()] 4074** cannot free sufficient memory to prevent the limit from being exceeded, 4075** the memory is allocated anyway and the current operation proceeds. 4076** 4077** ^A negative or zero value for N means that there is no soft heap limit and 4078** [sqlite3_release_memory()] will only be called when memory is exhausted. 4079** ^The default value for the soft heap limit is zero. 4080** 4081** ^(SQLite makes a best effort to honor the soft heap limit. 4082** But if the soft heap limit cannot be honored, execution will 4083** continue without error or notification.)^ This is why the limit is 4084** called a "soft" limit. It is advisory only. 4085** 4086** Prior to SQLite version 3.5.0, this routine only constrained the memory 4087** allocated by a single thread - the same thread in which this routine 4088** runs. Beginning with SQLite version 3.5.0, the soft heap limit is 4089** applied to all threads. The value specified for the soft heap limit 4090** is an upper bound on the total memory allocation for all threads. In 4091** version 3.5.0 there is no mechanism for limiting the heap usage for 4092** individual threads. 4093*/ 4094void sqlite3_soft_heap_limit(int); 4095 4096/* 4097** CAPI3REF: Extract Metadata About A Column Of A Table 4098** 4099** ^This routine returns metadata about a specific column of a specific 4100** database table accessible using the [database connection] handle 4101** passed as the first function argument. 4102** 4103** ^The column is identified by the second, third and fourth parameters to 4104** this function. ^The second parameter is either the name of the database 4105** (i.e. "main", "temp", or an attached database) containing the specified 4106** table or NULL. ^If it is NULL, then all attached databases are searched 4107** for the table using the same algorithm used by the database engine to 4108** resolve unqualified table references. 4109** 4110** ^The third and fourth parameters to this function are the table and column 4111** name of the desired column, respectively. Neither of these parameters 4112** may be NULL. 4113** 4114** ^Metadata is returned by writing to the memory locations passed as the 5th 4115** and subsequent parameters to this function. ^Any of these arguments may be 4116** NULL, in which case the corresponding element of metadata is omitted. 4117** 4118** ^(<blockquote> 4119** <table border="1"> 4120** <tr><th> Parameter <th> Output<br>Type <th> Description 4121** 4122** <tr><td> 5th <td> const char* <td> Data type 4123** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4124** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4125** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4126** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4127** </table> 4128** </blockquote>)^ 4129** 4130** ^The memory pointed to by the character pointers returned for the 4131** declaration type and collation sequence is valid only until the next 4132** call to any SQLite API function. 4133** 4134** ^If the specified table is actually a view, an [error code] is returned. 4135** 4136** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4137** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4138** parameters are set for the explicitly declared column. ^(If there is no 4139** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4140** parameters are set as follows: 4141** 4142** <pre> 4143** data type: "INTEGER" 4144** collation sequence: "BINARY" 4145** not null: 0 4146** primary key: 1 4147** auto increment: 0 4148** </pre>)^ 4149** 4150** ^(This function may load one or more schemas from database files. If an 4151** error occurs during this process, or if the requested table or column 4152** cannot be found, an [error code] is returned and an error message left 4153** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4154** 4155** ^This API is only available if the library was compiled with the 4156** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4157*/ 4158int sqlite3_table_column_metadata( 4159 sqlite3 *db, /* Connection handle */ 4160 const char *zDbName, /* Database name or NULL */ 4161 const char *zTableName, /* Table name */ 4162 const char *zColumnName, /* Column name */ 4163 char const **pzDataType, /* OUTPUT: Declared data type */ 4164 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4165 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4166 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4167 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4168); 4169 4170/* 4171** CAPI3REF: Load An Extension 4172** 4173** ^This interface loads an SQLite extension library from the named file. 4174** 4175** ^The sqlite3_load_extension() interface attempts to load an 4176** SQLite extension library contained in the file zFile. 4177** 4178** ^The entry point is zProc. 4179** ^zProc may be 0, in which case the name of the entry point 4180** defaults to "sqlite3_extension_init". 4181** ^The sqlite3_load_extension() interface returns 4182** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4183** ^If an error occurs and pzErrMsg is not 0, then the 4184** [sqlite3_load_extension()] interface shall attempt to 4185** fill *pzErrMsg with error message text stored in memory 4186** obtained from [sqlite3_malloc()]. The calling function 4187** should free this memory by calling [sqlite3_free()]. 4188** 4189** ^Extension loading must be enabled using 4190** [sqlite3_enable_load_extension()] prior to calling this API, 4191** otherwise an error will be returned. 4192** 4193** See also the [load_extension() SQL function]. 4194*/ 4195int sqlite3_load_extension( 4196 sqlite3 *db, /* Load the extension into this database connection */ 4197 const char *zFile, /* Name of the shared library containing extension */ 4198 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4199 char **pzErrMsg /* Put error message here if not 0 */ 4200); 4201 4202/* 4203** CAPI3REF: Enable Or Disable Extension Loading 4204** 4205** ^So as not to open security holes in older applications that are 4206** unprepared to deal with extension loading, and as a means of disabling 4207** extension loading while evaluating user-entered SQL, the following API 4208** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4209** 4210** ^Extension loading is off by default. See ticket #1863. 4211** ^Call the sqlite3_enable_load_extension() routine with onoff==1 4212** to turn extension loading on and call it with onoff==0 to turn 4213** it back off again. 4214*/ 4215int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4216 4217/* 4218** CAPI3REF: Automatically Load An Extensions 4219** 4220** ^This API can be invoked at program startup in order to register 4221** one or more statically linked extensions that will be available 4222** to all new [database connections]. 4223** 4224** ^(This routine stores a pointer to the extension entry point 4225** in an array that is obtained from [sqlite3_malloc()]. That memory 4226** is deallocated by [sqlite3_reset_auto_extension()].)^ 4227** 4228** ^This function registers an extension entry point that is 4229** automatically invoked whenever a new [database connection] 4230** is opened using [sqlite3_open()], [sqlite3_open16()], 4231** or [sqlite3_open_v2()]. 4232** ^Duplicate extensions are detected so calling this routine 4233** multiple times with the same extension is harmless. 4234** ^Automatic extensions apply across all threads. 4235*/ 4236int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4237 4238/* 4239** CAPI3REF: Reset Automatic Extension Loading 4240** 4241** ^(This function disables all previously registered automatic 4242** extensions. It undoes the effect of all prior 4243** [sqlite3_auto_extension()] calls.)^ 4244** 4245** ^This function disables automatic extensions in all threads. 4246*/ 4247void sqlite3_reset_auto_extension(void); 4248 4249/* 4250** The interface to the virtual-table mechanism is currently considered 4251** to be experimental. The interface might change in incompatible ways. 4252** If this is a problem for you, do not use the interface at this time. 4253** 4254** When the virtual-table mechanism stabilizes, we will declare the 4255** interface fixed, support it indefinitely, and remove this comment. 4256*/ 4257 4258/* 4259** Structures used by the virtual table interface 4260*/ 4261typedef struct sqlite3_vtab sqlite3_vtab; 4262typedef struct sqlite3_index_info sqlite3_index_info; 4263typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4264typedef struct sqlite3_module sqlite3_module; 4265 4266/* 4267** CAPI3REF: Virtual Table Object 4268** KEYWORDS: sqlite3_module {virtual table module} 4269** 4270** This structure, sometimes called a a "virtual table module", 4271** defines the implementation of a [virtual tables]. 4272** This structure consists mostly of methods for the module. 4273** 4274** ^A virtual table module is created by filling in a persistent 4275** instance of this structure and passing a pointer to that instance 4276** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4277** ^The registration remains valid until it is replaced by a different 4278** module or until the [database connection] closes. The content 4279** of this structure must not change while it is registered with 4280** any database connection. 4281*/ 4282struct sqlite3_module { 4283 int iVersion; 4284 int (*xCreate)(sqlite3*, void *pAux, 4285 int argc, const char *const*argv, 4286 sqlite3_vtab **ppVTab, char**); 4287 int (*xConnect)(sqlite3*, void *pAux, 4288 int argc, const char *const*argv, 4289 sqlite3_vtab **ppVTab, char**); 4290 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4291 int (*xDisconnect)(sqlite3_vtab *pVTab); 4292 int (*xDestroy)(sqlite3_vtab *pVTab); 4293 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4294 int (*xClose)(sqlite3_vtab_cursor*); 4295 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4296 int argc, sqlite3_value **argv); 4297 int (*xNext)(sqlite3_vtab_cursor*); 4298 int (*xEof)(sqlite3_vtab_cursor*); 4299 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4300 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4301 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4302 int (*xBegin)(sqlite3_vtab *pVTab); 4303 int (*xSync)(sqlite3_vtab *pVTab); 4304 int (*xCommit)(sqlite3_vtab *pVTab); 4305 int (*xRollback)(sqlite3_vtab *pVTab); 4306 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4307 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4308 void **ppArg); 4309 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4310}; 4311 4312/* 4313** CAPI3REF: Virtual Table Indexing Information 4314** KEYWORDS: sqlite3_index_info 4315** 4316** The sqlite3_index_info structure and its substructures is used to 4317** pass information into and receive the reply from the [xBestIndex] 4318** method of a [virtual table module]. The fields under **Inputs** are the 4319** inputs to xBestIndex and are read-only. xBestIndex inserts its 4320** results into the **Outputs** fields. 4321** 4322** ^(The aConstraint[] array records WHERE clause constraints of the form: 4323** 4324** <pre>column OP expr</pre> 4325** 4326** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 4327** stored in aConstraint[].op.)^ ^(The index of the column is stored in 4328** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 4329** expr on the right-hand side can be evaluated (and thus the constraint 4330** is usable) and false if it cannot.)^ 4331** 4332** ^The optimizer automatically inverts terms of the form "expr OP column" 4333** and makes other simplifications to the WHERE clause in an attempt to 4334** get as many WHERE clause terms into the form shown above as possible. 4335** ^The aConstraint[] array only reports WHERE clause terms that are 4336** relevant to the particular virtual table being queried. 4337** 4338** ^Information about the ORDER BY clause is stored in aOrderBy[]. 4339** ^Each term of aOrderBy records a column of the ORDER BY clause. 4340** 4341** The [xBestIndex] method must fill aConstraintUsage[] with information 4342** about what parameters to pass to xFilter. ^If argvIndex>0 then 4343** the right-hand side of the corresponding aConstraint[] is evaluated 4344** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 4345** is true, then the constraint is assumed to be fully handled by the 4346** virtual table and is not checked again by SQLite.)^ 4347** 4348** ^The idxNum and idxPtr values are recorded and passed into the 4349** [xFilter] method. 4350** ^[sqlite3_free()] is used to free idxPtr if and only if 4351** needToFreeIdxPtr is true. 4352** 4353** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 4354** the correct order to satisfy the ORDER BY clause so that no separate 4355** sorting step is required. 4356** 4357** ^The estimatedCost value is an estimate of the cost of doing the 4358** particular lookup. A full scan of a table with N entries should have 4359** a cost of N. A binary search of a table of N entries should have a 4360** cost of approximately log(N). 4361*/ 4362struct sqlite3_index_info { 4363 /* Inputs */ 4364 int nConstraint; /* Number of entries in aConstraint */ 4365 struct sqlite3_index_constraint { 4366 int iColumn; /* Column on left-hand side of constraint */ 4367 unsigned char op; /* Constraint operator */ 4368 unsigned char usable; /* True if this constraint is usable */ 4369 int iTermOffset; /* Used internally - xBestIndex should ignore */ 4370 } *aConstraint; /* Table of WHERE clause constraints */ 4371 int nOrderBy; /* Number of terms in the ORDER BY clause */ 4372 struct sqlite3_index_orderby { 4373 int iColumn; /* Column number */ 4374 unsigned char desc; /* True for DESC. False for ASC. */ 4375 } *aOrderBy; /* The ORDER BY clause */ 4376 /* Outputs */ 4377 struct sqlite3_index_constraint_usage { 4378 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 4379 unsigned char omit; /* Do not code a test for this constraint */ 4380 } *aConstraintUsage; 4381 int idxNum; /* Number used to identify the index */ 4382 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 4383 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 4384 int orderByConsumed; /* True if output is already ordered */ 4385 double estimatedCost; /* Estimated cost of using this index */ 4386}; 4387#define SQLITE_INDEX_CONSTRAINT_EQ 2 4388#define SQLITE_INDEX_CONSTRAINT_GT 4 4389#define SQLITE_INDEX_CONSTRAINT_LE 8 4390#define SQLITE_INDEX_CONSTRAINT_LT 16 4391#define SQLITE_INDEX_CONSTRAINT_GE 32 4392#define SQLITE_INDEX_CONSTRAINT_MATCH 64 4393 4394/* 4395** CAPI3REF: Register A Virtual Table Implementation 4396** 4397** ^These routines are used to register a new [virtual table module] name. 4398** ^Module names must be registered before 4399** creating a new [virtual table] using the module and before using a 4400** preexisting [virtual table] for the module. 4401** 4402** ^The module name is registered on the [database connection] specified 4403** by the first parameter. ^The name of the module is given by the 4404** second parameter. ^The third parameter is a pointer to 4405** the implementation of the [virtual table module]. ^The fourth 4406** parameter is an arbitrary client data pointer that is passed through 4407** into the [xCreate] and [xConnect] methods of the virtual table module 4408** when a new virtual table is be being created or reinitialized. 4409** 4410** ^The sqlite3_create_module_v2() interface has a fifth parameter which 4411** is a pointer to a destructor for the pClientData. ^SQLite will 4412** invoke the destructor function (if it is not NULL) when SQLite 4413** no longer needs the pClientData pointer. ^The sqlite3_create_module() 4414** interface is equivalent to sqlite3_create_module_v2() with a NULL 4415** destructor. 4416*/ 4417int sqlite3_create_module( 4418 sqlite3 *db, /* SQLite connection to register module with */ 4419 const char *zName, /* Name of the module */ 4420 const sqlite3_module *p, /* Methods for the module */ 4421 void *pClientData /* Client data for xCreate/xConnect */ 4422); 4423int sqlite3_create_module_v2( 4424 sqlite3 *db, /* SQLite connection to register module with */ 4425 const char *zName, /* Name of the module */ 4426 const sqlite3_module *p, /* Methods for the module */ 4427 void *pClientData, /* Client data for xCreate/xConnect */ 4428 void(*xDestroy)(void*) /* Module destructor function */ 4429); 4430 4431/* 4432** CAPI3REF: Virtual Table Instance Object 4433** KEYWORDS: sqlite3_vtab 4434** 4435** Every [virtual table module] implementation uses a subclass 4436** of this object to describe a particular instance 4437** of the [virtual table]. Each subclass will 4438** be tailored to the specific needs of the module implementation. 4439** The purpose of this superclass is to define certain fields that are 4440** common to all module implementations. 4441** 4442** ^Virtual tables methods can set an error message by assigning a 4443** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 4444** take care that any prior string is freed by a call to [sqlite3_free()] 4445** prior to assigning a new string to zErrMsg. ^After the error message 4446** is delivered up to the client application, the string will be automatically 4447** freed by sqlite3_free() and the zErrMsg field will be zeroed. 4448*/ 4449struct sqlite3_vtab { 4450 const sqlite3_module *pModule; /* The module for this virtual table */ 4451 int nRef; /* NO LONGER USED */ 4452 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 4453 /* Virtual table implementations will typically add additional fields */ 4454}; 4455 4456/* 4457** CAPI3REF: Virtual Table Cursor Object 4458** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 4459** 4460** Every [virtual table module] implementation uses a subclass of the 4461** following structure to describe cursors that point into the 4462** [virtual table] and are used 4463** to loop through the virtual table. Cursors are created using the 4464** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 4465** by the [sqlite3_module.xClose | xClose] method. Cursors are used 4466** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 4467** of the module. Each module implementation will define 4468** the content of a cursor structure to suit its own needs. 4469** 4470** This superclass exists in order to define fields of the cursor that 4471** are common to all implementations. 4472*/ 4473struct sqlite3_vtab_cursor { 4474 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 4475 /* Virtual table implementations will typically add additional fields */ 4476}; 4477 4478/* 4479** CAPI3REF: Declare The Schema Of A Virtual Table 4480** 4481** ^The [xCreate] and [xConnect] methods of a 4482** [virtual table module] call this interface 4483** to declare the format (the names and datatypes of the columns) of 4484** the virtual tables they implement. 4485*/ 4486int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 4487 4488/* 4489** CAPI3REF: Overload A Function For A Virtual Table 4490** 4491** ^(Virtual tables can provide alternative implementations of functions 4492** using the [xFindFunction] method of the [virtual table module]. 4493** But global versions of those functions 4494** must exist in order to be overloaded.)^ 4495** 4496** ^(This API makes sure a global version of a function with a particular 4497** name and number of parameters exists. If no such function exists 4498** before this API is called, a new function is created.)^ ^The implementation 4499** of the new function always causes an exception to be thrown. So 4500** the new function is not good for anything by itself. Its only 4501** purpose is to be a placeholder function that can be overloaded 4502** by a [virtual table]. 4503*/ 4504int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 4505 4506/* 4507** The interface to the virtual-table mechanism defined above (back up 4508** to a comment remarkably similar to this one) is currently considered 4509** to be experimental. The interface might change in incompatible ways. 4510** If this is a problem for you, do not use the interface at this time. 4511** 4512** When the virtual-table mechanism stabilizes, we will declare the 4513** interface fixed, support it indefinitely, and remove this comment. 4514*/ 4515 4516/* 4517** CAPI3REF: A Handle To An Open BLOB 4518** KEYWORDS: {BLOB handle} {BLOB handles} 4519** 4520** An instance of this object represents an open BLOB on which 4521** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 4522** ^Objects of this type are created by [sqlite3_blob_open()] 4523** and destroyed by [sqlite3_blob_close()]. 4524** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 4525** can be used to read or write small subsections of the BLOB. 4526** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 4527*/ 4528typedef struct sqlite3_blob sqlite3_blob; 4529 4530/* 4531** CAPI3REF: Open A BLOB For Incremental I/O 4532** 4533** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 4534** in row iRow, column zColumn, table zTable in database zDb; 4535** in other words, the same BLOB that would be selected by: 4536** 4537** <pre> 4538** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 4539** </pre>)^ 4540** 4541** ^If the flags parameter is non-zero, then the BLOB is opened for read 4542** and write access. ^If it is zero, the BLOB is opened for read access. 4543** ^It is not possible to open a column that is part of an index or primary 4544** key for writing. ^If [foreign key constraints] are enabled, it is 4545** not possible to open a column that is part of a [child key] for writing. 4546** 4547** ^Note that the database name is not the filename that contains 4548** the database but rather the symbolic name of the database that 4549** appears after the AS keyword when the database is connected using [ATTACH]. 4550** ^For the main database file, the database name is "main". 4551** ^For TEMP tables, the database name is "temp". 4552** 4553** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 4554** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 4555** to be a null pointer.)^ 4556** ^This function sets the [database connection] error code and message 4557** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 4558** functions. ^Note that the *ppBlob variable is always initialized in a 4559** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 4560** regardless of the success or failure of this routine. 4561** 4562** ^(If the row that a BLOB handle points to is modified by an 4563** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 4564** then the BLOB handle is marked as "expired". 4565** This is true if any column of the row is changed, even a column 4566** other than the one the BLOB handle is open on.)^ 4567** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 4568** a expired BLOB handle fail with an return code of [SQLITE_ABORT]. 4569** ^(Changes written into a BLOB prior to the BLOB expiring are not 4570** rolled back by the expiration of the BLOB. Such changes will eventually 4571** commit if the transaction continues to completion.)^ 4572** 4573** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 4574** the opened blob. ^The size of a blob may not be changed by this 4575** interface. Use the [UPDATE] SQL command to change the size of a 4576** blob. 4577** 4578** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 4579** and the built-in [zeroblob] SQL function can be used, if desired, 4580** to create an empty, zero-filled blob in which to read or write using 4581** this interface. 4582** 4583** To avoid a resource leak, every open [BLOB handle] should eventually 4584** be released by a call to [sqlite3_blob_close()]. 4585*/ 4586int sqlite3_blob_open( 4587 sqlite3*, 4588 const char *zDb, 4589 const char *zTable, 4590 const char *zColumn, 4591 sqlite3_int64 iRow, 4592 int flags, 4593 sqlite3_blob **ppBlob 4594); 4595 4596/* 4597** CAPI3REF: Close A BLOB Handle 4598** 4599** ^Closes an open [BLOB handle]. 4600** 4601** ^Closing a BLOB shall cause the current transaction to commit 4602** if there are no other BLOBs, no pending prepared statements, and the 4603** database connection is in [autocommit mode]. 4604** ^If any writes were made to the BLOB, they might be held in cache 4605** until the close operation if they will fit. 4606** 4607** ^(Closing the BLOB often forces the changes 4608** out to disk and so if any I/O errors occur, they will likely occur 4609** at the time when the BLOB is closed. Any errors that occur during 4610** closing are reported as a non-zero return value.)^ 4611** 4612** ^(The BLOB is closed unconditionally. Even if this routine returns 4613** an error code, the BLOB is still closed.)^ 4614** 4615** ^Calling this routine with a null pointer (such as would be returned 4616** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 4617*/ 4618int sqlite3_blob_close(sqlite3_blob *); 4619 4620/* 4621** CAPI3REF: Return The Size Of An Open BLOB 4622** 4623** ^Returns the size in bytes of the BLOB accessible via the 4624** successfully opened [BLOB handle] in its only argument. ^The 4625** incremental blob I/O routines can only read or overwriting existing 4626** blob content; they cannot change the size of a blob. 4627** 4628** This routine only works on a [BLOB handle] which has been created 4629** by a prior successful call to [sqlite3_blob_open()] and which has not 4630** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4631** to this routine results in undefined and probably undesirable behavior. 4632*/ 4633int sqlite3_blob_bytes(sqlite3_blob *); 4634 4635/* 4636** CAPI3REF: Read Data From A BLOB Incrementally 4637** 4638** ^(This function is used to read data from an open [BLOB handle] into a 4639** caller-supplied buffer. N bytes of data are copied into buffer Z 4640** from the open BLOB, starting at offset iOffset.)^ 4641** 4642** ^If offset iOffset is less than N bytes from the end of the BLOB, 4643** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 4644** less than zero, [SQLITE_ERROR] is returned and no data is read. 4645** ^The size of the blob (and hence the maximum value of N+iOffset) 4646** can be determined using the [sqlite3_blob_bytes()] interface. 4647** 4648** ^An attempt to read from an expired [BLOB handle] fails with an 4649** error code of [SQLITE_ABORT]. 4650** 4651** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 4652** Otherwise, an [error code] or an [extended error code] is returned.)^ 4653** 4654** This routine only works on a [BLOB handle] which has been created 4655** by a prior successful call to [sqlite3_blob_open()] and which has not 4656** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4657** to this routine results in undefined and probably undesirable behavior. 4658** 4659** See also: [sqlite3_blob_write()]. 4660*/ 4661int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 4662 4663/* 4664** CAPI3REF: Write Data Into A BLOB Incrementally 4665** 4666** ^This function is used to write data into an open [BLOB handle] from a 4667** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 4668** into the open BLOB, starting at offset iOffset. 4669** 4670** ^If the [BLOB handle] passed as the first argument was not opened for 4671** writing (the flags parameter to [sqlite3_blob_open()] was zero), 4672** this function returns [SQLITE_READONLY]. 4673** 4674** ^This function may only modify the contents of the BLOB; it is 4675** not possible to increase the size of a BLOB using this API. 4676** ^If offset iOffset is less than N bytes from the end of the BLOB, 4677** [SQLITE_ERROR] is returned and no data is written. ^If N is 4678** less than zero [SQLITE_ERROR] is returned and no data is written. 4679** The size of the BLOB (and hence the maximum value of N+iOffset) 4680** can be determined using the [sqlite3_blob_bytes()] interface. 4681** 4682** ^An attempt to write to an expired [BLOB handle] fails with an 4683** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 4684** before the [BLOB handle] expired are not rolled back by the 4685** expiration of the handle, though of course those changes might 4686** have been overwritten by the statement that expired the BLOB handle 4687** or by other independent statements. 4688** 4689** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 4690** Otherwise, an [error code] or an [extended error code] is returned.)^ 4691** 4692** This routine only works on a [BLOB handle] which has been created 4693** by a prior successful call to [sqlite3_blob_open()] and which has not 4694** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4695** to this routine results in undefined and probably undesirable behavior. 4696** 4697** See also: [sqlite3_blob_read()]. 4698*/ 4699int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 4700 4701/* 4702** CAPI3REF: Virtual File System Objects 4703** 4704** A virtual filesystem (VFS) is an [sqlite3_vfs] object 4705** that SQLite uses to interact 4706** with the underlying operating system. Most SQLite builds come with a 4707** single default VFS that is appropriate for the host computer. 4708** New VFSes can be registered and existing VFSes can be unregistered. 4709** The following interfaces are provided. 4710** 4711** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 4712** ^Names are case sensitive. 4713** ^Names are zero-terminated UTF-8 strings. 4714** ^If there is no match, a NULL pointer is returned. 4715** ^If zVfsName is NULL then the default VFS is returned. 4716** 4717** ^New VFSes are registered with sqlite3_vfs_register(). 4718** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 4719** ^The same VFS can be registered multiple times without injury. 4720** ^To make an existing VFS into the default VFS, register it again 4721** with the makeDflt flag set. If two different VFSes with the 4722** same name are registered, the behavior is undefined. If a 4723** VFS is registered with a name that is NULL or an empty string, 4724** then the behavior is undefined. 4725** 4726** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 4727** ^(If the default VFS is unregistered, another VFS is chosen as 4728** the default. The choice for the new VFS is arbitrary.)^ 4729*/ 4730sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 4731int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 4732int sqlite3_vfs_unregister(sqlite3_vfs*); 4733 4734/* 4735** CAPI3REF: Mutexes 4736** 4737** The SQLite core uses these routines for thread 4738** synchronization. Though they are intended for internal 4739** use by SQLite, code that links against SQLite is 4740** permitted to use any of these routines. 4741** 4742** The SQLite source code contains multiple implementations 4743** of these mutex routines. An appropriate implementation 4744** is selected automatically at compile-time. ^(The following 4745** implementations are available in the SQLite core: 4746** 4747** <ul> 4748** <li> SQLITE_MUTEX_OS2 4749** <li> SQLITE_MUTEX_PTHREAD 4750** <li> SQLITE_MUTEX_W32 4751** <li> SQLITE_MUTEX_NOOP 4752** </ul>)^ 4753** 4754** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 4755** that does no real locking and is appropriate for use in 4756** a single-threaded application. ^The SQLITE_MUTEX_OS2, 4757** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations 4758** are appropriate for use on OS/2, Unix, and Windows. 4759** 4760** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 4761** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 4762** implementation is included with the library. In this case the 4763** application must supply a custom mutex implementation using the 4764** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 4765** before calling sqlite3_initialize() or any other public sqlite3_ 4766** function that calls sqlite3_initialize().)^ 4767** 4768** ^The sqlite3_mutex_alloc() routine allocates a new 4769** mutex and returns a pointer to it. ^If it returns NULL 4770** that means that a mutex could not be allocated. ^SQLite 4771** will unwind its stack and return an error. ^(The argument 4772** to sqlite3_mutex_alloc() is one of these integer constants: 4773** 4774** <ul> 4775** <li> SQLITE_MUTEX_FAST 4776** <li> SQLITE_MUTEX_RECURSIVE 4777** <li> SQLITE_MUTEX_STATIC_MASTER 4778** <li> SQLITE_MUTEX_STATIC_MEM 4779** <li> SQLITE_MUTEX_STATIC_MEM2 4780** <li> SQLITE_MUTEX_STATIC_PRNG 4781** <li> SQLITE_MUTEX_STATIC_LRU 4782** <li> SQLITE_MUTEX_STATIC_LRU2 4783** </ul>)^ 4784** 4785** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 4786** cause sqlite3_mutex_alloc() to create 4787** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 4788** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 4789** The mutex implementation does not need to make a distinction 4790** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 4791** not want to. ^SQLite will only request a recursive mutex in 4792** cases where it really needs one. ^If a faster non-recursive mutex 4793** implementation is available on the host platform, the mutex subsystem 4794** might return such a mutex in response to SQLITE_MUTEX_FAST. 4795** 4796** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 4797** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 4798** a pointer to a static preexisting mutex. ^Six static mutexes are 4799** used by the current version of SQLite. Future versions of SQLite 4800** may add additional static mutexes. Static mutexes are for internal 4801** use by SQLite only. Applications that use SQLite mutexes should 4802** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 4803** SQLITE_MUTEX_RECURSIVE. 4804** 4805** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 4806** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 4807** returns a different mutex on every call. ^But for the static 4808** mutex types, the same mutex is returned on every call that has 4809** the same type number. 4810** 4811** ^The sqlite3_mutex_free() routine deallocates a previously 4812** allocated dynamic mutex. ^SQLite is careful to deallocate every 4813** dynamic mutex that it allocates. The dynamic mutexes must not be in 4814** use when they are deallocated. Attempting to deallocate a static 4815** mutex results in undefined behavior. ^SQLite never deallocates 4816** a static mutex. 4817** 4818** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 4819** to enter a mutex. ^If another thread is already within the mutex, 4820** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 4821** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 4822** upon successful entry. ^(Mutexes created using 4823** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 4824** In such cases the, 4825** mutex must be exited an equal number of times before another thread 4826** can enter.)^ ^(If the same thread tries to enter any other 4827** kind of mutex more than once, the behavior is undefined. 4828** SQLite will never exhibit 4829** such behavior in its own use of mutexes.)^ 4830** 4831** ^(Some systems (for example, Windows 95) do not support the operation 4832** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 4833** will always return SQLITE_BUSY. The SQLite core only ever uses 4834** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 4835** 4836** ^The sqlite3_mutex_leave() routine exits a mutex that was 4837** previously entered by the same thread. ^(The behavior 4838** is undefined if the mutex is not currently entered by the 4839** calling thread or is not currently allocated. SQLite will 4840** never do either.)^ 4841** 4842** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 4843** sqlite3_mutex_leave() is a NULL pointer, then all three routines 4844** behave as no-ops. 4845** 4846** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 4847*/ 4848sqlite3_mutex *sqlite3_mutex_alloc(int); 4849void sqlite3_mutex_free(sqlite3_mutex*); 4850void sqlite3_mutex_enter(sqlite3_mutex*); 4851int sqlite3_mutex_try(sqlite3_mutex*); 4852void sqlite3_mutex_leave(sqlite3_mutex*); 4853 4854/* 4855** CAPI3REF: Mutex Methods Object 4856** 4857** An instance of this structure defines the low-level routines 4858** used to allocate and use mutexes. 4859** 4860** Usually, the default mutex implementations provided by SQLite are 4861** sufficient, however the user has the option of substituting a custom 4862** implementation for specialized deployments or systems for which SQLite 4863** does not provide a suitable implementation. In this case, the user 4864** creates and populates an instance of this structure to pass 4865** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 4866** Additionally, an instance of this structure can be used as an 4867** output variable when querying the system for the current mutex 4868** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 4869** 4870** ^The xMutexInit method defined by this structure is invoked as 4871** part of system initialization by the sqlite3_initialize() function. 4872** ^The xMutexInit routine is calle by SQLite exactly once for each 4873** effective call to [sqlite3_initialize()]. 4874** 4875** ^The xMutexEnd method defined by this structure is invoked as 4876** part of system shutdown by the sqlite3_shutdown() function. The 4877** implementation of this method is expected to release all outstanding 4878** resources obtained by the mutex methods implementation, especially 4879** those obtained by the xMutexInit method. ^The xMutexEnd() 4880** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 4881** 4882** ^(The remaining seven methods defined by this structure (xMutexAlloc, 4883** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 4884** xMutexNotheld) implement the following interfaces (respectively): 4885** 4886** <ul> 4887** <li> [sqlite3_mutex_alloc()] </li> 4888** <li> [sqlite3_mutex_free()] </li> 4889** <li> [sqlite3_mutex_enter()] </li> 4890** <li> [sqlite3_mutex_try()] </li> 4891** <li> [sqlite3_mutex_leave()] </li> 4892** <li> [sqlite3_mutex_held()] </li> 4893** <li> [sqlite3_mutex_notheld()] </li> 4894** </ul>)^ 4895** 4896** The only difference is that the public sqlite3_XXX functions enumerated 4897** above silently ignore any invocations that pass a NULL pointer instead 4898** of a valid mutex handle. The implementations of the methods defined 4899** by this structure are not required to handle this case, the results 4900** of passing a NULL pointer instead of a valid mutex handle are undefined 4901** (i.e. it is acceptable to provide an implementation that segfaults if 4902** it is passed a NULL pointer). 4903** 4904** The xMutexInit() method must be threadsafe. ^It must be harmless to 4905** invoke xMutexInit() mutiple times within the same process and without 4906** intervening calls to xMutexEnd(). Second and subsequent calls to 4907** xMutexInit() must be no-ops. 4908** 4909** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 4910** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 4911** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 4912** memory allocation for a fast or recursive mutex. 4913** 4914** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 4915** called, but only if the prior call to xMutexInit returned SQLITE_OK. 4916** If xMutexInit fails in any way, it is expected to clean up after itself 4917** prior to returning. 4918*/ 4919typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 4920struct sqlite3_mutex_methods { 4921 int (*xMutexInit)(void); 4922 int (*xMutexEnd)(void); 4923 sqlite3_mutex *(*xMutexAlloc)(int); 4924 void (*xMutexFree)(sqlite3_mutex *); 4925 void (*xMutexEnter)(sqlite3_mutex *); 4926 int (*xMutexTry)(sqlite3_mutex *); 4927 void (*xMutexLeave)(sqlite3_mutex *); 4928 int (*xMutexHeld)(sqlite3_mutex *); 4929 int (*xMutexNotheld)(sqlite3_mutex *); 4930}; 4931 4932/* 4933** CAPI3REF: Mutex Verification Routines 4934** 4935** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 4936** are intended for use inside assert() statements. ^The SQLite core 4937** never uses these routines except inside an assert() and applications 4938** are advised to follow the lead of the core. ^The SQLite core only 4939** provides implementations for these routines when it is compiled 4940** with the SQLITE_DEBUG flag. ^External mutex implementations 4941** are only required to provide these routines if SQLITE_DEBUG is 4942** defined and if NDEBUG is not defined. 4943** 4944** ^These routines should return true if the mutex in their argument 4945** is held or not held, respectively, by the calling thread. 4946** 4947** ^The implementation is not required to provided versions of these 4948** routines that actually work. If the implementation does not provide working 4949** versions of these routines, it should at least provide stubs that always 4950** return true so that one does not get spurious assertion failures. 4951** 4952** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 4953** the routine should return 1. This seems counter-intuitive since 4954** clearly the mutex cannot be held if it does not exist. But the 4955** the reason the mutex does not exist is because the build is not 4956** using mutexes. And we do not want the assert() containing the 4957** call to sqlite3_mutex_held() to fail, so a non-zero return is 4958** the appropriate thing to do. ^The sqlite3_mutex_notheld() 4959** interface should also return 1 when given a NULL pointer. 4960*/ 4961#ifndef NDEBUG 4962int sqlite3_mutex_held(sqlite3_mutex*); 4963int sqlite3_mutex_notheld(sqlite3_mutex*); 4964#endif 4965 4966/* 4967** CAPI3REF: Mutex Types 4968** 4969** The [sqlite3_mutex_alloc()] interface takes a single argument 4970** which is one of these integer constants. 4971** 4972** The set of static mutexes may change from one SQLite release to the 4973** next. Applications that override the built-in mutex logic must be 4974** prepared to accommodate additional static mutexes. 4975*/ 4976#define SQLITE_MUTEX_FAST 0 4977#define SQLITE_MUTEX_RECURSIVE 1 4978#define SQLITE_MUTEX_STATIC_MASTER 2 4979#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 4980#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 4981#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 4982#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 4983#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 4984#define SQLITE_MUTEX_STATIC_LRU2 7 /* lru page list */ 4985 4986/* 4987** CAPI3REF: Retrieve the mutex for a database connection 4988** 4989** ^This interface returns a pointer the [sqlite3_mutex] object that 4990** serializes access to the [database connection] given in the argument 4991** when the [threading mode] is Serialized. 4992** ^If the [threading mode] is Single-thread or Multi-thread then this 4993** routine returns a NULL pointer. 4994*/ 4995sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 4996 4997/* 4998** CAPI3REF: Low-Level Control Of Database Files 4999** 5000** ^The [sqlite3_file_control()] interface makes a direct call to the 5001** xFileControl method for the [sqlite3_io_methods] object associated 5002** with a particular database identified by the second argument. ^The 5003** name of the database "main" for the main database or "temp" for the 5004** TEMP database, or the name that appears after the AS keyword for 5005** databases that are added using the [ATTACH] SQL command. 5006** ^A NULL pointer can be used in place of "main" to refer to the 5007** main database file. 5008** ^The third and fourth parameters to this routine 5009** are passed directly through to the second and third parameters of 5010** the xFileControl method. ^The return value of the xFileControl 5011** method becomes the return value of this routine. 5012** 5013** ^If the second parameter (zDbName) does not match the name of any 5014** open database file, then SQLITE_ERROR is returned. ^This error 5015** code is not remembered and will not be recalled by [sqlite3_errcode()] 5016** or [sqlite3_errmsg()]. The underlying xFileControl method might 5017** also return SQLITE_ERROR. There is no way to distinguish between 5018** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5019** xFileControl method. 5020** 5021** See also: [SQLITE_FCNTL_LOCKSTATE] 5022*/ 5023int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5024 5025/* 5026** CAPI3REF: Testing Interface 5027** 5028** ^The sqlite3_test_control() interface is used to read out internal 5029** state of SQLite and to inject faults into SQLite for testing 5030** purposes. ^The first parameter is an operation code that determines 5031** the number, meaning, and operation of all subsequent parameters. 5032** 5033** This interface is not for use by applications. It exists solely 5034** for verifying the correct operation of the SQLite library. Depending 5035** on how the SQLite library is compiled, this interface might not exist. 5036** 5037** The details of the operation codes, their meanings, the parameters 5038** they take, and what they do are all subject to change without notice. 5039** Unlike most of the SQLite API, this function is not guaranteed to 5040** operate consistently from one release to the next. 5041*/ 5042int sqlite3_test_control(int op, ...); 5043 5044/* 5045** CAPI3REF: Testing Interface Operation Codes 5046** 5047** These constants are the valid operation code parameters used 5048** as the first argument to [sqlite3_test_control()]. 5049** 5050** These parameters and their meanings are subject to change 5051** without notice. These values are for testing purposes only. 5052** Applications should not use any of these parameters or the 5053** [sqlite3_test_control()] interface. 5054*/ 5055#define SQLITE_TESTCTRL_FIRST 5 5056#define SQLITE_TESTCTRL_PRNG_SAVE 5 5057#define SQLITE_TESTCTRL_PRNG_RESTORE 6 5058#define SQLITE_TESTCTRL_PRNG_RESET 7 5059#define SQLITE_TESTCTRL_BITVEC_TEST 8 5060#define SQLITE_TESTCTRL_FAULT_INSTALL 9 5061#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5062#define SQLITE_TESTCTRL_PENDING_BYTE 11 5063#define SQLITE_TESTCTRL_ASSERT 12 5064#define SQLITE_TESTCTRL_ALWAYS 13 5065#define SQLITE_TESTCTRL_RESERVE 14 5066#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 5067#define SQLITE_TESTCTRL_ISKEYWORD 16 5068#define SQLITE_TESTCTRL_PGHDRSZ 17 5069#define SQLITE_TESTCTRL_LAST 17 5070 5071/* 5072** CAPI3REF: SQLite Runtime Status 5073** 5074** ^This interface is used to retrieve runtime status information 5075** about the preformance of SQLite, and optionally to reset various 5076** highwater marks. ^The first argument is an integer code for 5077** the specific parameter to measure. ^(Recognized integer codes 5078** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].)^ 5079** ^The current value of the parameter is returned into *pCurrent. 5080** ^The highest recorded value is returned in *pHighwater. ^If the 5081** resetFlag is true, then the highest record value is reset after 5082** *pHighwater is written. ^(Some parameters do not record the highest 5083** value. For those parameters 5084** nothing is written into *pHighwater and the resetFlag is ignored.)^ 5085** ^(Other parameters record only the highwater mark and not the current 5086** value. For these latter parameters nothing is written into *pCurrent.)^ 5087** 5088** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 5089** non-zero [error code] on failure. 5090** 5091** This routine is threadsafe but is not atomic. This routine can be 5092** called while other threads are running the same or different SQLite 5093** interfaces. However the values returned in *pCurrent and 5094** *pHighwater reflect the status of SQLite at different points in time 5095** and it is possible that another thread might change the parameter 5096** in between the times when *pCurrent and *pHighwater are written. 5097** 5098** See also: [sqlite3_db_status()] 5099*/ 5100int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 5101 5102 5103/* 5104** CAPI3REF: Status Parameters 5105** 5106** These integer constants designate various run-time status parameters 5107** that can be returned by [sqlite3_status()]. 5108** 5109** <dl> 5110** ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 5111** <dd>This parameter is the current amount of memory checked out 5112** using [sqlite3_malloc()], either directly or indirectly. The 5113** figure includes calls made to [sqlite3_malloc()] by the application 5114** and internal memory usage by the SQLite library. Scratch memory 5115** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 5116** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 5117** this parameter. The amount returned is the sum of the allocation 5118** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 5119** 5120** ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 5121** <dd>This parameter records the largest memory allocation request 5122** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 5123** internal equivalents). Only the value returned in the 5124** *pHighwater parameter to [sqlite3_status()] is of interest. 5125** The value written into the *pCurrent parameter is undefined.</dd>)^ 5126** 5127** ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 5128** <dd>This parameter returns the number of pages used out of the 5129** [pagecache memory allocator] that was configured using 5130** [SQLITE_CONFIG_PAGECACHE]. The 5131** value returned is in pages, not in bytes.</dd>)^ 5132** 5133** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5134** <dd>This parameter returns the number of bytes of page cache 5135** allocation which could not be statisfied by the [SQLITE_CONFIG_PAGECACHE] 5136** buffer and where forced to overflow to [sqlite3_malloc()]. The 5137** returned value includes allocations that overflowed because they 5138** where too large (they were larger than the "sz" parameter to 5139** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 5140** no space was left in the page cache.</dd>)^ 5141** 5142** ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 5143** <dd>This parameter records the largest memory allocation request 5144** handed to [pagecache memory allocator]. Only the value returned in the 5145** *pHighwater parameter to [sqlite3_status()] is of interest. 5146** The value written into the *pCurrent parameter is undefined.</dd>)^ 5147** 5148** ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 5149** <dd>This parameter returns the number of allocations used out of the 5150** [scratch memory allocator] configured using 5151** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5152** in bytes. Since a single thread may only have one scratch allocation 5153** outstanding at time, this parameter also reports the number of threads 5154** using scratch memory at the same time.</dd>)^ 5155** 5156** ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5157** <dd>This parameter returns the number of bytes of scratch memory 5158** allocation which could not be statisfied by the [SQLITE_CONFIG_SCRATCH] 5159** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5160** returned include overflows because the requested allocation was too 5161** larger (that is, because the requested allocation was larger than the 5162** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5163** slots were available. 5164** </dd>)^ 5165** 5166** ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5167** <dd>This parameter records the largest memory allocation request 5168** handed to [scratch memory allocator]. Only the value returned in the 5169** *pHighwater parameter to [sqlite3_status()] is of interest. 5170** The value written into the *pCurrent parameter is undefined.</dd>)^ 5171** 5172** ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 5173** <dd>This parameter records the deepest parser stack. It is only 5174** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 5175** </dl> 5176** 5177** New status parameters may be added from time to time. 5178*/ 5179#define SQLITE_STATUS_MEMORY_USED 0 5180#define SQLITE_STATUS_PAGECACHE_USED 1 5181#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5182#define SQLITE_STATUS_SCRATCH_USED 3 5183#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5184#define SQLITE_STATUS_MALLOC_SIZE 5 5185#define SQLITE_STATUS_PARSER_STACK 6 5186#define SQLITE_STATUS_PAGECACHE_SIZE 7 5187#define SQLITE_STATUS_SCRATCH_SIZE 8 5188 5189/* 5190** CAPI3REF: Database Connection Status 5191** 5192** ^This interface is used to retrieve runtime status information 5193** about a single [database connection]. ^The first argument is the 5194** database connection object to be interrogated. ^The second argument 5195** is an integer constant, taken from the set of 5196** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros, that 5197** determiness the parameter to interrogate. The set of 5198** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros is likely 5199** to grow in future releases of SQLite. 5200** 5201** ^The current value of the requested parameter is written into *pCur 5202** and the highest instantaneous value is written into *pHiwtr. ^If 5203** the resetFlg is true, then the highest instantaneous value is 5204** reset back down to the current value. 5205** 5206** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5207*/ 5208int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5209 5210/* 5211** CAPI3REF: Status Parameters for database connections 5212** 5213** These constants are the available integer "verbs" that can be passed as 5214** the second argument to the [sqlite3_db_status()] interface. 5215** 5216** New verbs may be added in future releases of SQLite. Existing verbs 5217** might be discontinued. Applications should check the return code from 5218** [sqlite3_db_status()] to make sure that the call worked. 5219** The [sqlite3_db_status()] interface will return a non-zero error code 5220** if a discontinued or unsupported verb is invoked. 5221** 5222** <dl> 5223** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5224** <dd>This parameter returns the number of lookaside memory slots currently 5225** checked out.</dd>)^ 5226** 5227** <dt>SQLITE_DBSTATUS_CACHE_USED</dt> 5228** <dd>^This parameter returns the approximate number of of bytes of heap 5229** memory used by all pager caches associated with the database connection. 5230** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 5231** checked out.</dd>)^ 5232** </dl> 5233*/ 5234#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 5235#define SQLITE_DBSTATUS_CACHE_USED 1 5236#define SQLITE_DBSTATUS_MAX 1 /* Largest defined DBSTATUS */ 5237 5238 5239/* 5240** CAPI3REF: Prepared Statement Status 5241** 5242** ^(Each prepared statement maintains various 5243** [SQLITE_STMTSTATUS_SORT | counters] that measure the number 5244** of times it has performed specific operations.)^ These counters can 5245** be used to monitor the performance characteristics of the prepared 5246** statements. For example, if the number of table steps greatly exceeds 5247** the number of table searches or result rows, that would tend to indicate 5248** that the prepared statement is using a full table scan rather than 5249** an index. 5250** 5251** ^(This interface is used to retrieve and reset counter values from 5252** a [prepared statement]. The first argument is the prepared statement 5253** object to be interrogated. The second argument 5254** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter] 5255** to be interrogated.)^ 5256** ^The current value of the requested counter is returned. 5257** ^If the resetFlg is true, then the counter is reset to zero after this 5258** interface call returns. 5259** 5260** See also: [sqlite3_status()] and [sqlite3_db_status()]. 5261*/ 5262int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 5263 5264/* 5265** CAPI3REF: Status Parameters for prepared statements 5266** 5267** These preprocessor macros define integer codes that name counter 5268** values associated with the [sqlite3_stmt_status()] interface. 5269** The meanings of the various counters are as follows: 5270** 5271** <dl> 5272** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 5273** <dd>^This is the number of times that SQLite has stepped forward in 5274** a table as part of a full table scan. Large numbers for this counter 5275** may indicate opportunities for performance improvement through 5276** careful use of indices.</dd> 5277** 5278** <dt>SQLITE_STMTSTATUS_SORT</dt> 5279** <dd>^This is the number of sort operations that have occurred. 5280** A non-zero value in this counter may indicate an opportunity to 5281** improvement performance through careful use of indices.</dd> 5282** 5283** <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 5284** <dd>^This is the number of rows inserted into transient indices that 5285** were created automatically in order to help joins run faster. 5286** A non-zero value in this counter may indicate an opportunity to 5287** improvement performance by adding permanent indices that do not 5288** need to be reinitialized each time the statement is run.</dd> 5289** 5290** </dl> 5291*/ 5292#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 5293#define SQLITE_STMTSTATUS_SORT 2 5294#define SQLITE_STMTSTATUS_AUTOINDEX 3 5295 5296/* 5297** CAPI3REF: Custom Page Cache Object 5298** 5299** The sqlite3_pcache type is opaque. It is implemented by 5300** the pluggable module. The SQLite core has no knowledge of 5301** its size or internal structure and never deals with the 5302** sqlite3_pcache object except by holding and passing pointers 5303** to the object. 5304** 5305** See [sqlite3_pcache_methods] for additional information. 5306*/ 5307typedef struct sqlite3_pcache sqlite3_pcache; 5308 5309/* 5310** CAPI3REF: Application Defined Page Cache. 5311** KEYWORDS: {page cache} 5312** 5313** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can 5314** register an alternative page cache implementation by passing in an 5315** instance of the sqlite3_pcache_methods structure.)^ The majority of the 5316** heap memory used by SQLite is used by the page cache to cache data read 5317** from, or ready to be written to, the database file. By implementing a 5318** custom page cache using this API, an application can control more 5319** precisely the amount of memory consumed by SQLite, the way in which 5320** that memory is allocated and released, and the policies used to 5321** determine exactly which parts of a database file are cached and for 5322** how long. 5323** 5324** ^(The contents of the sqlite3_pcache_methods structure are copied to an 5325** internal buffer by SQLite within the call to [sqlite3_config]. Hence 5326** the application may discard the parameter after the call to 5327** [sqlite3_config()] returns.)^ 5328** 5329** ^The xInit() method is called once for each call to [sqlite3_initialize()] 5330** (usually only once during the lifetime of the process). ^(The xInit() 5331** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^ 5332** ^The xInit() method can set up up global structures and/or any mutexes 5333** required by the custom page cache implementation. 5334** 5335** ^The xShutdown() method is called from within [sqlite3_shutdown()], 5336** if the application invokes this API. It can be used to clean up 5337** any outstanding resources before process shutdown, if required. 5338** 5339** ^SQLite holds a [SQLITE_MUTEX_RECURSIVE] mutex when it invokes 5340** the xInit method, so the xInit method need not be threadsafe. ^The 5341** xShutdown method is only called from [sqlite3_shutdown()] so it does 5342** not need to be threadsafe either. All other methods must be threadsafe 5343** in multithreaded applications. 5344** 5345** ^SQLite will never invoke xInit() more than once without an intervening 5346** call to xShutdown(). 5347** 5348** ^The xCreate() method is used to construct a new cache instance. SQLite 5349** will typically create one cache instance for each open database file, 5350** though this is not guaranteed. ^The 5351** first parameter, szPage, is the size in bytes of the pages that must 5352** be allocated by the cache. ^szPage will not be a power of two. ^szPage 5353** will the page size of the database file that is to be cached plus an 5354** increment (here called "R") of about 100 or 200. ^SQLite will use the 5355** extra R bytes on each page to store metadata about the underlying 5356** database page on disk. The value of R depends 5357** on the SQLite version, the target platform, and how SQLite was compiled. 5358** ^R is constant for a particular build of SQLite. ^The second argument to 5359** xCreate(), bPurgeable, is true if the cache being created will 5360** be used to cache database pages of a file stored on disk, or 5361** false if it is used for an in-memory database. ^The cache implementation 5362** does not have to do anything special based with the value of bPurgeable; 5363** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 5364** never invoke xUnpin() except to deliberately delete a page. 5365** ^In other words, a cache created with bPurgeable set to false will 5366** never contain any unpinned pages. 5367** 5368** ^(The xCachesize() method may be called at any time by SQLite to set the 5369** suggested maximum cache-size (number of pages stored by) the cache 5370** instance passed as the first argument. This is the value configured using 5371** the SQLite "[PRAGMA cache_size]" command.)^ ^As with the bPurgeable 5372** parameter, the implementation is not required to do anything with this 5373** value; it is advisory only. 5374** 5375** ^The xPagecount() method should return the number of pages currently 5376** stored in the cache. 5377** 5378** ^The xFetch() method is used to fetch a page and return a pointer to it. 5379** ^A 'page', in this context, is a buffer of szPage bytes aligned at an 5380** 8-byte boundary. ^The page to be fetched is determined by the key. ^The 5381** mimimum key value is 1. After it has been retrieved using xFetch, the page 5382** is considered to be "pinned". 5383** 5384** ^If the requested page is already in the page cache, then the page cache 5385** implementation must return a pointer to the page buffer with its content 5386** intact. ^(If the requested page is not already in the cache, then the 5387** behavior of the cache implementation is determined by the value of the 5388** createFlag parameter passed to xFetch, according to the following table: 5389** 5390** <table border=1 width=85% align=center> 5391** <tr><th> createFlag <th> Behaviour when page is not already in cache 5392** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 5393** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 5394** Otherwise return NULL. 5395** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 5396** NULL if allocating a new page is effectively impossible. 5397** </table>)^ 5398** 5399** SQLite will normally invoke xFetch() with a createFlag of 0 or 1. If 5400** a call to xFetch() with createFlag==1 returns NULL, then SQLite will 5401** attempt to unpin one or more cache pages by spilling the content of 5402** pinned pages to disk and synching the operating system disk cache. After 5403** attempting to unpin pages, the xFetch() method will be invoked again with 5404** a createFlag of 2. 5405** 5406** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 5407** as its second argument. ^(If the third parameter, discard, is non-zero, 5408** then the page should be evicted from the cache. In this case SQLite 5409** assumes that the next time the page is retrieved from the cache using 5410** the xFetch() method, it will be zeroed.)^ ^If the discard parameter is 5411** zero, then the page is considered to be unpinned. ^The cache implementation 5412** may choose to evict unpinned pages at any time. 5413** 5414** ^(The cache is not required to perform any reference counting. A single 5415** call to xUnpin() unpins the page regardless of the number of prior calls 5416** to xFetch().)^ 5417** 5418** ^The xRekey() method is used to change the key value associated with the 5419** page passed as the second argument from oldKey to newKey. ^If the cache 5420** previously contains an entry associated with newKey, it should be 5421** discarded. ^Any prior cache entry associated with newKey is guaranteed not 5422** to be pinned. 5423** 5424** ^When SQLite calls the xTruncate() method, the cache must discard all 5425** existing cache entries with page numbers (keys) greater than or equal 5426** to the value of the iLimit parameter passed to xTruncate(). ^If any 5427** of these pages are pinned, they are implicitly unpinned, meaning that 5428** they can be safely discarded. 5429** 5430** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 5431** All resources associated with the specified cache should be freed. ^After 5432** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 5433** handle invalid, and will not use it with any other sqlite3_pcache_methods 5434** functions. 5435*/ 5436typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 5437struct sqlite3_pcache_methods { 5438 void *pArg; 5439 int (*xInit)(void*); 5440 void (*xShutdown)(void*); 5441 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 5442 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 5443 int (*xPagecount)(sqlite3_pcache*); 5444 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 5445 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 5446 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 5447 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 5448 void (*xDestroy)(sqlite3_pcache*); 5449}; 5450 5451/* 5452** CAPI3REF: Online Backup Object 5453** 5454** The sqlite3_backup object records state information about an ongoing 5455** online backup operation. ^The sqlite3_backup object is created by 5456** a call to [sqlite3_backup_init()] and is destroyed by a call to 5457** [sqlite3_backup_finish()]. 5458** 5459** See Also: [Using the SQLite Online Backup API] 5460*/ 5461typedef struct sqlite3_backup sqlite3_backup; 5462 5463/* 5464** CAPI3REF: Online Backup API. 5465** 5466** The backup API copies the content of one database into another. 5467** It is useful either for creating backups of databases or 5468** for copying in-memory databases to or from persistent files. 5469** 5470** See Also: [Using the SQLite Online Backup API] 5471** 5472** ^Exclusive access is required to the destination database for the 5473** duration of the operation. ^However the source database is only 5474** read-locked while it is actually being read; it is not locked 5475** continuously for the entire backup operation. ^Thus, the backup may be 5476** performed on a live source database without preventing other users from 5477** reading or writing to the source database while the backup is underway. 5478** 5479** ^(To perform a backup operation: 5480** <ol> 5481** <li><b>sqlite3_backup_init()</b> is called once to initialize the 5482** backup, 5483** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 5484** the data between the two databases, and finally 5485** <li><b>sqlite3_backup_finish()</b> is called to release all resources 5486** associated with the backup operation. 5487** </ol>)^ 5488** There should be exactly one call to sqlite3_backup_finish() for each 5489** successful call to sqlite3_backup_init(). 5490** 5491** <b>sqlite3_backup_init()</b> 5492** 5493** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 5494** [database connection] associated with the destination database 5495** and the database name, respectively. 5496** ^The database name is "main" for the main database, "temp" for the 5497** temporary database, or the name specified after the AS keyword in 5498** an [ATTACH] statement for an attached database. 5499** ^The S and M arguments passed to 5500** sqlite3_backup_init(D,N,S,M) identify the [database connection] 5501** and database name of the source database, respectively. 5502** ^The source and destination [database connections] (parameters S and D) 5503** must be different or else sqlite3_backup_init(D,N,S,M) will file with 5504** an error. 5505** 5506** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 5507** returned and an error code and error message are store3d in the 5508** destination [database connection] D. 5509** ^The error code and message for the failed call to sqlite3_backup_init() 5510** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 5511** [sqlite3_errmsg16()] functions. 5512** ^A successful call to sqlite3_backup_init() returns a pointer to an 5513** [sqlite3_backup] object. 5514** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 5515** sqlite3_backup_finish() functions to perform the specified backup 5516** operation. 5517** 5518** <b>sqlite3_backup_step()</b> 5519** 5520** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 5521** the source and destination databases specified by [sqlite3_backup] object B. 5522** ^If N is negative, all remaining source pages are copied. 5523** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 5524** are still more pages to be copied, then the function resturns [SQLITE_OK]. 5525** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 5526** from source to destination, then it returns [SQLITE_DONE]. 5527** ^If an error occurs while running sqlite3_backup_step(B,N), 5528** then an [error code] is returned. ^As well as [SQLITE_OK] and 5529** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 5530** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 5531** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 5532** 5533** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 5534** <ol> 5535** <li> the destination database was opened read-only, or 5536** <li> the destination database is using write-ahead-log journaling 5537** and the destination and source page sizes differ, or 5538** <li> The destination database is an in-memory database and the 5539** destination and source page sizes differ. 5540** </ol>)^ 5541** 5542** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 5543** the [sqlite3_busy_handler | busy-handler function] 5544** is invoked (if one is specified). ^If the 5545** busy-handler returns non-zero before the lock is available, then 5546** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 5547** sqlite3_backup_step() can be retried later. ^If the source 5548** [database connection] 5549** is being used to write to the source database when sqlite3_backup_step() 5550** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 5551** case the call to sqlite3_backup_step() can be retried later on. ^(If 5552** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 5553** [SQLITE_READONLY] is returned, then 5554** there is no point in retrying the call to sqlite3_backup_step(). These 5555** errors are considered fatal.)^ The application must accept 5556** that the backup operation has failed and pass the backup operation handle 5557** to the sqlite3_backup_finish() to release associated resources. 5558** 5559** ^The first call to sqlite3_backup_step() obtains an exclusive lock 5560** on the destination file. ^The exclusive lock is not released until either 5561** sqlite3_backup_finish() is called or the backup operation is complete 5562** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 5563** sqlite3_backup_step() obtains a [shared lock] on the source database that 5564** lasts for the duration of the sqlite3_backup_step() call. 5565** ^Because the source database is not locked between calls to 5566** sqlite3_backup_step(), the source database may be modified mid-way 5567** through the backup process. ^If the source database is modified by an 5568** external process or via a database connection other than the one being 5569** used by the backup operation, then the backup will be automatically 5570** restarted by the next call to sqlite3_backup_step(). ^If the source 5571** database is modified by the using the same database connection as is used 5572** by the backup operation, then the backup database is automatically 5573** updated at the same time. 5574** 5575** <b>sqlite3_backup_finish()</b> 5576** 5577** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 5578** application wishes to abandon the backup operation, the application 5579** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 5580** ^The sqlite3_backup_finish() interfaces releases all 5581** resources associated with the [sqlite3_backup] object. 5582** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 5583** active write-transaction on the destination database is rolled back. 5584** The [sqlite3_backup] object is invalid 5585** and may not be used following a call to sqlite3_backup_finish(). 5586** 5587** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 5588** sqlite3_backup_step() errors occurred, regardless or whether or not 5589** sqlite3_backup_step() completed. 5590** ^If an out-of-memory condition or IO error occurred during any prior 5591** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 5592** sqlite3_backup_finish() returns the corresponding [error code]. 5593** 5594** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 5595** is not a permanent error and does not affect the return value of 5596** sqlite3_backup_finish(). 5597** 5598** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b> 5599** 5600** ^Each call to sqlite3_backup_step() sets two values inside 5601** the [sqlite3_backup] object: the number of pages still to be backed 5602** up and the total number of pages in the source databae file. 5603** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 5604** retrieve these two values, respectively. 5605** 5606** ^The values returned by these functions are only updated by 5607** sqlite3_backup_step(). ^If the source database is modified during a backup 5608** operation, then the values are not updated to account for any extra 5609** pages that need to be updated or the size of the source database file 5610** changing. 5611** 5612** <b>Concurrent Usage of Database Handles</b> 5613** 5614** ^The source [database connection] may be used by the application for other 5615** purposes while a backup operation is underway or being initialized. 5616** ^If SQLite is compiled and configured to support threadsafe database 5617** connections, then the source database connection may be used concurrently 5618** from within other threads. 5619** 5620** However, the application must guarantee that the destination 5621** [database connection] is not passed to any other API (by any thread) after 5622** sqlite3_backup_init() is called and before the corresponding call to 5623** sqlite3_backup_finish(). SQLite does not currently check to see 5624** if the application incorrectly accesses the destination [database connection] 5625** and so no error code is reported, but the operations may malfunction 5626** nevertheless. Use of the destination database connection while a 5627** backup is in progress might also also cause a mutex deadlock. 5628** 5629** If running in [shared cache mode], the application must 5630** guarantee that the shared cache used by the destination database 5631** is not accessed while the backup is running. In practice this means 5632** that the application must guarantee that the disk file being 5633** backed up to is not accessed by any connection within the process, 5634** not just the specific connection that was passed to sqlite3_backup_init(). 5635** 5636** The [sqlite3_backup] object itself is partially threadsafe. Multiple 5637** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 5638** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 5639** APIs are not strictly speaking threadsafe. If they are invoked at the 5640** same time as another thread is invoking sqlite3_backup_step() it is 5641** possible that they return invalid values. 5642*/ 5643sqlite3_backup *sqlite3_backup_init( 5644 sqlite3 *pDest, /* Destination database handle */ 5645 const char *zDestName, /* Destination database name */ 5646 sqlite3 *pSource, /* Source database handle */ 5647 const char *zSourceName /* Source database name */ 5648); 5649int sqlite3_backup_step(sqlite3_backup *p, int nPage); 5650int sqlite3_backup_finish(sqlite3_backup *p); 5651int sqlite3_backup_remaining(sqlite3_backup *p); 5652int sqlite3_backup_pagecount(sqlite3_backup *p); 5653 5654/* 5655** CAPI3REF: Unlock Notification 5656** 5657** ^When running in shared-cache mode, a database operation may fail with 5658** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 5659** individual tables within the shared-cache cannot be obtained. See 5660** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 5661** ^This API may be used to register a callback that SQLite will invoke 5662** when the connection currently holding the required lock relinquishes it. 5663** ^This API is only available if the library was compiled with the 5664** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 5665** 5666** See Also: [Using the SQLite Unlock Notification Feature]. 5667** 5668** ^Shared-cache locks are released when a database connection concludes 5669** its current transaction, either by committing it or rolling it back. 5670** 5671** ^When a connection (known as the blocked connection) fails to obtain a 5672** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 5673** identity of the database connection (the blocking connection) that 5674** has locked the required resource is stored internally. ^After an 5675** application receives an SQLITE_LOCKED error, it may call the 5676** sqlite3_unlock_notify() method with the blocked connection handle as 5677** the first argument to register for a callback that will be invoked 5678** when the blocking connections current transaction is concluded. ^The 5679** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 5680** call that concludes the blocking connections transaction. 5681** 5682** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 5683** there is a chance that the blocking connection will have already 5684** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 5685** If this happens, then the specified callback is invoked immediately, 5686** from within the call to sqlite3_unlock_notify().)^ 5687** 5688** ^If the blocked connection is attempting to obtain a write-lock on a 5689** shared-cache table, and more than one other connection currently holds 5690** a read-lock on the same table, then SQLite arbitrarily selects one of 5691** the other connections to use as the blocking connection. 5692** 5693** ^(There may be at most one unlock-notify callback registered by a 5694** blocked connection. If sqlite3_unlock_notify() is called when the 5695** blocked connection already has a registered unlock-notify callback, 5696** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 5697** called with a NULL pointer as its second argument, then any existing 5698** unlock-notify callback is cancelled. ^The blocked connections 5699** unlock-notify callback may also be canceled by closing the blocked 5700** connection using [sqlite3_close()]. 5701** 5702** The unlock-notify callback is not reentrant. If an application invokes 5703** any sqlite3_xxx API functions from within an unlock-notify callback, a 5704** crash or deadlock may be the result. 5705** 5706** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 5707** returns SQLITE_OK. 5708** 5709** <b>Callback Invocation Details</b> 5710** 5711** When an unlock-notify callback is registered, the application provides a 5712** single void* pointer that is passed to the callback when it is invoked. 5713** However, the signature of the callback function allows SQLite to pass 5714** it an array of void* context pointers. The first argument passed to 5715** an unlock-notify callback is a pointer to an array of void* pointers, 5716** and the second is the number of entries in the array. 5717** 5718** When a blocking connections transaction is concluded, there may be 5719** more than one blocked connection that has registered for an unlock-notify 5720** callback. ^If two or more such blocked connections have specified the 5721** same callback function, then instead of invoking the callback function 5722** multiple times, it is invoked once with the set of void* context pointers 5723** specified by the blocked connections bundled together into an array. 5724** This gives the application an opportunity to prioritize any actions 5725** related to the set of unblocked database connections. 5726** 5727** <b>Deadlock Detection</b> 5728** 5729** Assuming that after registering for an unlock-notify callback a 5730** database waits for the callback to be issued before taking any further 5731** action (a reasonable assumption), then using this API may cause the 5732** application to deadlock. For example, if connection X is waiting for 5733** connection Y's transaction to be concluded, and similarly connection 5734** Y is waiting on connection X's transaction, then neither connection 5735** will proceed and the system may remain deadlocked indefinitely. 5736** 5737** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 5738** detection. ^If a given call to sqlite3_unlock_notify() would put the 5739** system in a deadlocked state, then SQLITE_LOCKED is returned and no 5740** unlock-notify callback is registered. The system is said to be in 5741** a deadlocked state if connection A has registered for an unlock-notify 5742** callback on the conclusion of connection B's transaction, and connection 5743** B has itself registered for an unlock-notify callback when connection 5744** A's transaction is concluded. ^Indirect deadlock is also detected, so 5745** the system is also considered to be deadlocked if connection B has 5746** registered for an unlock-notify callback on the conclusion of connection 5747** C's transaction, where connection C is waiting on connection A. ^Any 5748** number of levels of indirection are allowed. 5749** 5750** <b>The "DROP TABLE" Exception</b> 5751** 5752** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 5753** always appropriate to call sqlite3_unlock_notify(). There is however, 5754** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 5755** SQLite checks if there are any currently executing SELECT statements 5756** that belong to the same connection. If there are, SQLITE_LOCKED is 5757** returned. In this case there is no "blocking connection", so invoking 5758** sqlite3_unlock_notify() results in the unlock-notify callback being 5759** invoked immediately. If the application then re-attempts the "DROP TABLE" 5760** or "DROP INDEX" query, an infinite loop might be the result. 5761** 5762** One way around this problem is to check the extended error code returned 5763** by an sqlite3_step() call. ^(If there is a blocking connection, then the 5764** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 5765** the special "DROP TABLE/INDEX" case, the extended error code is just 5766** SQLITE_LOCKED.)^ 5767*/ 5768int sqlite3_unlock_notify( 5769 sqlite3 *pBlocked, /* Waiting connection */ 5770 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 5771 void *pNotifyArg /* Argument to pass to xNotify */ 5772); 5773 5774 5775/* 5776** CAPI3REF: String Comparison 5777** 5778** ^The [sqlite3_strnicmp()] API allows applications and extensions to 5779** compare the contents of two buffers containing UTF-8 strings in a 5780** case-indendent fashion, using the same definition of case independence 5781** that SQLite uses internally when comparing identifiers. 5782*/ 5783int sqlite3_strnicmp(const char *, const char *, int); 5784 5785/* 5786** CAPI3REF: Error Logging Interface 5787** 5788** ^The [sqlite3_log()] interface writes a message into the error log 5789** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 5790** ^If logging is enabled, the zFormat string and subsequent arguments are 5791** used with [sqlite3_snprintf()] to generate the final output string. 5792** 5793** The sqlite3_log() interface is intended for use by extensions such as 5794** virtual tables, collating functions, and SQL functions. While there is 5795** nothing to prevent an application from calling sqlite3_log(), doing so 5796** is considered bad form. 5797** 5798** The zFormat string must not be NULL. 5799** 5800** To avoid deadlocks and other threading problems, the sqlite3_log() routine 5801** will not use dynamically allocated memory. The log message is stored in 5802** a fixed-length buffer on the stack. If the log message is longer than 5803** a few hundred characters, it will be truncated to the length of the 5804** buffer. 5805*/ 5806void sqlite3_log(int iErrCode, const char *zFormat, ...); 5807 5808/* 5809** CAPI3REF: Write-Ahead Log Commit Hook 5810** 5811** ^The [sqlite3_wal_hook()] function is used to register a callback that 5812** will be invoked each time a database connection commits data to a 5813** [write-ahead log] (i.e. whenever a transaction is committed in 5814** [journal_mode | journal_mode=WAL mode]). 5815** 5816** ^The callback is invoked by SQLite after the commit has taken place and 5817** the associated write-lock on the database released, so the implementation 5818** may read, write or [checkpoint] the database as required. 5819** 5820** ^The first parameter passed to the callback function when it is invoked 5821** is a copy of the third parameter passed to sqlite3_wal_hook() when 5822** registering the callback. ^The second is a copy of the database handle. 5823** ^The third parameter is the name of the database that was written to - 5824** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 5825** is the number of pages currently in the write-ahead log file, 5826** including those that were just committed. 5827** 5828** The callback function should normally return [SQLITE_OK]. ^If an error 5829** code is returned, that error will propagate back up through the 5830** SQLite code base to cause the statement that provoked the callback 5831** to report an error, though the commit will have still occurred. If the 5832** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 5833** that does not correspond to any valid SQLite error code, the results 5834** are undefined. 5835** 5836** A single database handle may have at most a single write-ahead log callback 5837** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 5838** previously registered write-ahead log callback. ^Note that the 5839** [sqlite3_wal_autocheckpoint()] interface and the 5840** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 5841** those overwrite any prior [sqlite3_wal_hook()] settings. 5842*/ 5843void *sqlite3_wal_hook( 5844 sqlite3*, 5845 int(*)(void *,sqlite3*,const char*,int), 5846 void* 5847); 5848 5849/* 5850** CAPI3REF: Configure an auto-checkpoint 5851** 5852** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 5853** [sqlite3_wal_hook()] that causes any database on [database connection] D 5854** to automatically [checkpoint] 5855** after committing a transaction if there are N or 5856** more frames in the [write-ahead log] file. ^Passing zero or 5857** a negative value as the nFrame parameter disables automatic 5858** checkpoints entirely. 5859** 5860** ^The callback registered by this function replaces any existing callback 5861** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 5862** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 5863** configured by this function. 5864** 5865** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 5866** from SQL. 5867** 5868** ^Every new [database connection] defaults to having the auto-checkpoint 5869** enabled with a threshold of 1000 pages. The use of this interface 5870** is only necessary if the default setting is found to be suboptimal 5871** for a particular application. 5872*/ 5873int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 5874 5875/* 5876** CAPI3REF: Checkpoint a database 5877** 5878** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 5879** on [database connection] D to be [checkpointed]. ^If X is NULL or an 5880** empty string, then a checkpoint is run on all databases of 5881** connection D. ^If the database connection D is not in 5882** [WAL | write-ahead log mode] then this interface is a harmless no-op. 5883** 5884** ^The [wal_checkpoint pragma] can be used to invoke this interface 5885** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 5886** [wal_autocheckpoint pragma] can be used to cause this interface to be 5887** run whenever the WAL reaches a certain size threshold. 5888*/ 5889int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 5890 5891/* 5892** Undo the hack that converts floating point types to integer for 5893** builds on processors without floating point support. 5894*/ 5895#ifdef SQLITE_OMIT_FLOATING_POINT 5896# undef double 5897#endif 5898 5899#ifdef __cplusplus 5900} /* End of the 'extern "C"' block */ 5901#endif 5902#endif 5903