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 evaluates 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 iterating 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 specifying 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** successfully 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#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 480 481/* 482** CAPI3REF: Device Characteristics 483** 484** The xDeviceCharacteristics method of the [sqlite3_io_methods] 485** object returns an integer which is a vector of the these 486** bit values expressing I/O characteristics of the mass storage 487** device that holds the file that the [sqlite3_io_methods] 488** refers to. 489** 490** The SQLITE_IOCAP_ATOMIC property means that all writes of 491** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 492** mean that writes of blocks that are nnn bytes in size and 493** are aligned to an address which is an integer multiple of 494** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 495** that when data is appended to a file, the data is appended 496** first then the size of the file is extended, never the other 497** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 498** information is written to disk in the same order as calls 499** to xWrite(). 500*/ 501#define SQLITE_IOCAP_ATOMIC 0x00000001 502#define SQLITE_IOCAP_ATOMIC512 0x00000002 503#define SQLITE_IOCAP_ATOMIC1K 0x00000004 504#define SQLITE_IOCAP_ATOMIC2K 0x00000008 505#define SQLITE_IOCAP_ATOMIC4K 0x00000010 506#define SQLITE_IOCAP_ATOMIC8K 0x00000020 507#define SQLITE_IOCAP_ATOMIC16K 0x00000040 508#define SQLITE_IOCAP_ATOMIC32K 0x00000080 509#define SQLITE_IOCAP_ATOMIC64K 0x00000100 510#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 511#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 512#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 513 514/* 515** CAPI3REF: File Locking Levels 516** 517** SQLite uses one of these integer values as the second 518** argument to calls it makes to the xLock() and xUnlock() methods 519** of an [sqlite3_io_methods] object. 520*/ 521#define SQLITE_LOCK_NONE 0 522#define SQLITE_LOCK_SHARED 1 523#define SQLITE_LOCK_RESERVED 2 524#define SQLITE_LOCK_PENDING 3 525#define SQLITE_LOCK_EXCLUSIVE 4 526 527/* 528** CAPI3REF: Synchronization Type Flags 529** 530** When SQLite invokes the xSync() method of an 531** [sqlite3_io_methods] object it uses a combination of 532** these integer values as the second argument. 533** 534** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 535** sync operation only needs to flush data to mass storage. Inode 536** information need not be flushed. If the lower four bits of the flag 537** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 538** If the lower four bits equal SQLITE_SYNC_FULL, that means 539** to use Mac OS X style fullsync instead of fsync(). 540*/ 541#define SQLITE_SYNC_NORMAL 0x00002 542#define SQLITE_SYNC_FULL 0x00003 543#define SQLITE_SYNC_DATAONLY 0x00010 544 545/* 546** CAPI3REF: OS Interface Open File Handle 547** 548** An [sqlite3_file] object represents an open file in the 549** [sqlite3_vfs | OS interface layer]. Individual OS interface 550** implementations will 551** want to subclass this object by appending additional fields 552** for their own use. The pMethods entry is a pointer to an 553** [sqlite3_io_methods] object that defines methods for performing 554** I/O operations on the open file. 555*/ 556typedef struct sqlite3_file sqlite3_file; 557struct sqlite3_file { 558 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 559}; 560 561/* 562** CAPI3REF: OS Interface File Virtual Methods Object 563** 564** Every file opened by the [sqlite3_vfs] xOpen method populates an 565** [sqlite3_file] object (or, more commonly, a subclass of the 566** [sqlite3_file] object) with a pointer to an instance of this object. 567** This object defines the methods used to perform various operations 568** against the open file represented by the [sqlite3_file] object. 569** 570** If the xOpen method sets the sqlite3_file.pMethods element 571** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 572** may be invoked even if the xOpen reported that it failed. The 573** only way to prevent a call to xClose following a failed xOpen 574** is for the xOpen to set the sqlite3_file.pMethods element to NULL. 575** 576** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 577** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 578** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 579** flag may be ORed in to indicate that only the data of the file 580** and not its inode needs to be synced. 581** 582** The integer values to xLock() and xUnlock() are one of 583** <ul> 584** <li> [SQLITE_LOCK_NONE], 585** <li> [SQLITE_LOCK_SHARED], 586** <li> [SQLITE_LOCK_RESERVED], 587** <li> [SQLITE_LOCK_PENDING], or 588** <li> [SQLITE_LOCK_EXCLUSIVE]. 589** </ul> 590** xLock() increases the lock. xUnlock() decreases the lock. 591** The xCheckReservedLock() method checks whether any database connection, 592** either in this process or in some other process, is holding a RESERVED, 593** PENDING, or EXCLUSIVE lock on the file. It returns true 594** if such a lock exists and false otherwise. 595** 596** The xFileControl() method is a generic interface that allows custom 597** VFS implementations to directly control an open file using the 598** [sqlite3_file_control()] interface. The second "op" argument is an 599** integer opcode. The third argument is a generic pointer intended to 600** point to a structure that may contain arguments or space in which to 601** write return values. Potential uses for xFileControl() might be 602** functions to enable blocking locks with timeouts, to change the 603** locking strategy (for example to use dot-file locks), to inquire 604** about the status of a lock, or to break stale locks. The SQLite 605** core reserves all opcodes less than 100 for its own use. 606** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 607** Applications that define a custom xFileControl method should use opcodes 608** greater than 100 to avoid conflicts. 609** 610** The xSectorSize() method returns the sector size of the 611** device that underlies the file. The sector size is the 612** minimum write that can be performed without disturbing 613** other bytes in the file. The xDeviceCharacteristics() 614** method returns a bit vector describing behaviors of the 615** underlying device: 616** 617** <ul> 618** <li> [SQLITE_IOCAP_ATOMIC] 619** <li> [SQLITE_IOCAP_ATOMIC512] 620** <li> [SQLITE_IOCAP_ATOMIC1K] 621** <li> [SQLITE_IOCAP_ATOMIC2K] 622** <li> [SQLITE_IOCAP_ATOMIC4K] 623** <li> [SQLITE_IOCAP_ATOMIC8K] 624** <li> [SQLITE_IOCAP_ATOMIC16K] 625** <li> [SQLITE_IOCAP_ATOMIC32K] 626** <li> [SQLITE_IOCAP_ATOMIC64K] 627** <li> [SQLITE_IOCAP_SAFE_APPEND] 628** <li> [SQLITE_IOCAP_SEQUENTIAL] 629** </ul> 630** 631** The SQLITE_IOCAP_ATOMIC property means that all writes of 632** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 633** mean that writes of blocks that are nnn bytes in size and 634** are aligned to an address which is an integer multiple of 635** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 636** that when data is appended to a file, the data is appended 637** first then the size of the file is extended, never the other 638** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 639** information is written to disk in the same order as calls 640** to xWrite(). 641** 642** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 643** in the unread portions of the buffer with zeros. A VFS that 644** fails to zero-fill short reads might seem to work. However, 645** failure to zero-fill short reads will eventually lead to 646** database corruption. 647*/ 648typedef struct sqlite3_io_methods sqlite3_io_methods; 649struct sqlite3_io_methods { 650 int iVersion; 651 int (*xClose)(sqlite3_file*); 652 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 653 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 654 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 655 int (*xSync)(sqlite3_file*, int flags); 656 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 657 int (*xLock)(sqlite3_file*, int); 658 int (*xUnlock)(sqlite3_file*, int); 659 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 660 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 661 int (*xSectorSize)(sqlite3_file*); 662 int (*xDeviceCharacteristics)(sqlite3_file*); 663 /* Methods above are valid for version 1 */ 664 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 665 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 666 void (*xShmBarrier)(sqlite3_file*); 667 int (*xShmUnmap)(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** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 695** extends and truncates the database file in chunks of a size specified 696** by the user. The fourth argument to [sqlite3_file_control()] should 697** point to an integer (type int) containing the new chunk-size to use 698** for the nominated database. Allocating database file space in large 699** chunks (say 1MB at a time), may reduce file-system fragmentation and 700** improve performance on some systems. 701*/ 702#define SQLITE_FCNTL_LOCKSTATE 1 703#define SQLITE_GET_LOCKPROXYFILE 2 704#define SQLITE_SET_LOCKPROXYFILE 3 705#define SQLITE_LAST_ERRNO 4 706#define SQLITE_FCNTL_SIZE_HINT 5 707#define SQLITE_FCNTL_CHUNK_SIZE 6 708 709/* 710** CAPI3REF: Mutex Handle 711** 712** The mutex module within SQLite defines [sqlite3_mutex] to be an 713** abstract type for a mutex object. The SQLite core never looks 714** at the internal representation of an [sqlite3_mutex]. It only 715** deals with pointers to the [sqlite3_mutex] object. 716** 717** Mutexes are created using [sqlite3_mutex_alloc()]. 718*/ 719typedef struct sqlite3_mutex sqlite3_mutex; 720 721/* 722** CAPI3REF: OS Interface Object 723** 724** An instance of the sqlite3_vfs object defines the interface between 725** the SQLite core and the underlying operating system. The "vfs" 726** in the name of the object stands for "virtual file system". 727** 728** The value of the iVersion field is initially 1 but may be larger in 729** future versions of SQLite. Additional fields may be appended to this 730** object when the iVersion value is increased. Note that the structure 731** of the sqlite3_vfs object changes in the transaction between 732** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 733** modified. 734** 735** The szOsFile field is the size of the subclassed [sqlite3_file] 736** structure used by this VFS. mxPathname is the maximum length of 737** a pathname in this VFS. 738** 739** Registered sqlite3_vfs objects are kept on a linked list formed by 740** the pNext pointer. The [sqlite3_vfs_register()] 741** and [sqlite3_vfs_unregister()] interfaces manage this list 742** in a thread-safe way. The [sqlite3_vfs_find()] interface 743** searches the list. Neither the application code nor the VFS 744** implementation should use the pNext pointer. 745** 746** The pNext field is the only field in the sqlite3_vfs 747** structure that SQLite will ever modify. SQLite will only access 748** or modify this field while holding a particular static mutex. 749** The application should never modify anything within the sqlite3_vfs 750** object once the object has been registered. 751** 752** The zName field holds the name of the VFS module. The name must 753** be unique across all VFS modules. 754** 755** ^SQLite will guarantee that the zFilename parameter to xOpen 756** is either a NULL pointer or string obtained 757** from xFullPathname(). ^SQLite further guarantees that 758** the string will be valid and unchanged until xClose() is 759** called. Because of the previous sentence, 760** the [sqlite3_file] can safely store a pointer to the 761** filename if it needs to remember the filename for some reason. 762** If the zFilename parameter to xOpen is a NULL pointer then xOpen 763** must invent its own temporary name for the file. ^Whenever the 764** xFilename parameter is NULL it will also be the case that the 765** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 766** 767** The flags argument to xOpen() includes all bits set in 768** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 769** or [sqlite3_open16()] is used, then flags includes at least 770** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 771** If xOpen() opens a file read-only then it sets *pOutFlags to 772** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 773** 774** ^(SQLite will also add one of the following flags to the xOpen() 775** call, depending on the object being opened: 776** 777** <ul> 778** <li> [SQLITE_OPEN_MAIN_DB] 779** <li> [SQLITE_OPEN_MAIN_JOURNAL] 780** <li> [SQLITE_OPEN_TEMP_DB] 781** <li> [SQLITE_OPEN_TEMP_JOURNAL] 782** <li> [SQLITE_OPEN_TRANSIENT_DB] 783** <li> [SQLITE_OPEN_SUBJOURNAL] 784** <li> [SQLITE_OPEN_MASTER_JOURNAL] 785** <li> [SQLITE_OPEN_WAL] 786** </ul>)^ 787** 788** The file I/O implementation can use the object type flags to 789** change the way it deals with files. For example, an application 790** that does not care about crash recovery or rollback might make 791** the open of a journal file a no-op. Writes to this journal would 792** also be no-ops, and any attempt to read the journal would return 793** SQLITE_IOERR. Or the implementation might recognize that a database 794** file will be doing page-aligned sector reads and writes in a random 795** order and set up its I/O subsystem accordingly. 796** 797** SQLite might also add one of the following flags to the xOpen method: 798** 799** <ul> 800** <li> [SQLITE_OPEN_DELETEONCLOSE] 801** <li> [SQLITE_OPEN_EXCLUSIVE] 802** </ul> 803** 804** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 805** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 806** will be set for TEMP databases and their journals, transient 807** databases, and subjournals. 808** 809** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 810** with the [SQLITE_OPEN_CREATE] flag, which are both directly 811** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 812** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 813** SQLITE_OPEN_CREATE, is used to indicate that file should always 814** be created, and that it is an error if it already exists. 815** It is <i>not</i> used to indicate the file should be opened 816** for exclusive access. 817** 818** ^At least szOsFile bytes of memory are allocated by SQLite 819** to hold the [sqlite3_file] structure passed as the third 820** argument to xOpen. The xOpen method does not have to 821** allocate the structure; it should just fill it in. Note that 822** the xOpen method must set the sqlite3_file.pMethods to either 823** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 824** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 825** element will be valid after xOpen returns regardless of the success 826** or failure of the xOpen call. 827** 828** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 829** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 830** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 831** to test whether a file is at least readable. The file can be a 832** directory. 833** 834** ^SQLite will always allocate at least mxPathname+1 bytes for the 835** output buffer xFullPathname. The exact size of the output buffer 836** is also passed as a parameter to both methods. If the output buffer 837** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 838** handled as a fatal error by SQLite, vfs implementations should endeavor 839** to prevent this by setting mxPathname to a sufficiently large value. 840** 841** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 842** interfaces are not strictly a part of the filesystem, but they are 843** included in the VFS structure for completeness. 844** The xRandomness() function attempts to return nBytes bytes 845** of good-quality randomness into zOut. The return value is 846** the actual number of bytes of randomness obtained. 847** The xSleep() method causes the calling thread to sleep for at 848** least the number of microseconds given. ^The xCurrentTime() 849** method returns a Julian Day Number for the current date and time as 850** a floating point value. 851** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 852** Day Number multipled by 86400000 (the number of milliseconds in 853** a 24-hour day). 854** ^SQLite will use the xCurrentTimeInt64() method to get the current 855** date and time if that method is available (if iVersion is 2 or 856** greater and the function pointer is not NULL) and will fall back 857** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 858*/ 859typedef struct sqlite3_vfs sqlite3_vfs; 860struct sqlite3_vfs { 861 int iVersion; /* Structure version number (currently 2) */ 862 int szOsFile; /* Size of subclassed sqlite3_file */ 863 int mxPathname; /* Maximum file pathname length */ 864 sqlite3_vfs *pNext; /* Next registered VFS */ 865 const char *zName; /* Name of this virtual file system */ 866 void *pAppData; /* Pointer to application-specific data */ 867 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 868 int flags, int *pOutFlags); 869 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 870 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 871 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 872 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 873 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 874 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 875 void (*xDlClose)(sqlite3_vfs*, void*); 876 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 877 int (*xSleep)(sqlite3_vfs*, int microseconds); 878 int (*xCurrentTime)(sqlite3_vfs*, double*); 879 int (*xGetLastError)(sqlite3_vfs*, int, char *); 880 /* 881 ** The methods above are in version 1 of the sqlite_vfs object 882 ** definition. Those that follow are added in version 2 or later 883 */ 884 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 885 /* 886 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 887 ** New fields may be appended in figure versions. The iVersion 888 ** value will increment whenever this happens. 889 */ 890}; 891 892/* 893** CAPI3REF: Flags for the xAccess VFS method 894** 895** These integer constants can be used as the third parameter to 896** the xAccess method of an [sqlite3_vfs] object. They determine 897** what kind of permissions the xAccess method is looking for. 898** With SQLITE_ACCESS_EXISTS, the xAccess method 899** simply checks whether the file exists. 900** With SQLITE_ACCESS_READWRITE, the xAccess method 901** checks whether the named directory is both readable and writable 902** (in other words, if files can be added, removed, and renamed within 903** the directory). 904** The SQLITE_ACCESS_READWRITE constant is currently used only by the 905** [temp_store_directory pragma], though this could change in a future 906** release of SQLite. 907** With SQLITE_ACCESS_READ, the xAccess method 908** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 909** currently unused, though it might be used in a future release of 910** SQLite. 911*/ 912#define SQLITE_ACCESS_EXISTS 0 913#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 914#define SQLITE_ACCESS_READ 2 /* Unused */ 915 916/* 917** CAPI3REF: Flags for the xShmLock VFS method 918** 919** These integer constants define the various locking operations 920** allowed by the xShmLock method of [sqlite3_io_methods]. The 921** following are the only legal combinations of flags to the 922** xShmLock method: 923** 924** <ul> 925** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 926** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 927** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 928** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 929** </ul> 930** 931** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 932** was given no the corresponding lock. 933** 934** The xShmLock method can transition between unlocked and SHARED or 935** between unlocked and EXCLUSIVE. It cannot transition between SHARED 936** and EXCLUSIVE. 937*/ 938#define SQLITE_SHM_UNLOCK 1 939#define SQLITE_SHM_LOCK 2 940#define SQLITE_SHM_SHARED 4 941#define SQLITE_SHM_EXCLUSIVE 8 942 943/* 944** CAPI3REF: Maximum xShmLock index 945** 946** The xShmLock method on [sqlite3_io_methods] may use values 947** between 0 and this upper bound as its "offset" argument. 948** The SQLite core will never attempt to acquire or release a 949** lock outside of this range 950*/ 951#define SQLITE_SHM_NLOCK 8 952 953 954/* 955** CAPI3REF: Initialize The SQLite Library 956** 957** ^The sqlite3_initialize() routine initializes the 958** SQLite library. ^The sqlite3_shutdown() routine 959** deallocates any resources that were allocated by sqlite3_initialize(). 960** These routines are designed to aid in process initialization and 961** shutdown on embedded systems. Workstation applications using 962** SQLite normally do not need to invoke either of these routines. 963** 964** A call to sqlite3_initialize() is an "effective" call if it is 965** the first time sqlite3_initialize() is invoked during the lifetime of 966** the process, or if it is the first time sqlite3_initialize() is invoked 967** following a call to sqlite3_shutdown(). ^(Only an effective call 968** of sqlite3_initialize() does any initialization. All other calls 969** are harmless no-ops.)^ 970** 971** A call to sqlite3_shutdown() is an "effective" call if it is the first 972** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 973** an effective call to sqlite3_shutdown() does any deinitialization. 974** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 975** 976** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 977** is not. The sqlite3_shutdown() interface must only be called from a 978** single thread. All open [database connections] must be closed and all 979** other SQLite resources must be deallocated prior to invoking 980** sqlite3_shutdown(). 981** 982** Among other things, ^sqlite3_initialize() will invoke 983** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 984** will invoke sqlite3_os_end(). 985** 986** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 987** ^If for some reason, sqlite3_initialize() is unable to initialize 988** the library (perhaps it is unable to allocate a needed resource such 989** as a mutex) it returns an [error code] other than [SQLITE_OK]. 990** 991** ^The sqlite3_initialize() routine is called internally by many other 992** SQLite interfaces so that an application usually does not need to 993** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 994** calls sqlite3_initialize() so the SQLite library will be automatically 995** initialized when [sqlite3_open()] is called if it has not be initialized 996** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 997** compile-time option, then the automatic calls to sqlite3_initialize() 998** are omitted and the application must call sqlite3_initialize() directly 999** prior to using any other SQLite interface. For maximum portability, 1000** it is recommended that applications always invoke sqlite3_initialize() 1001** directly prior to using any other SQLite interface. Future releases 1002** of SQLite may require this. In other words, the behavior exhibited 1003** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1004** default behavior in some future release of SQLite. 1005** 1006** The sqlite3_os_init() routine does operating-system specific 1007** initialization of the SQLite library. The sqlite3_os_end() 1008** routine undoes the effect of sqlite3_os_init(). Typical tasks 1009** performed by these routines include allocation or deallocation 1010** of static resources, initialization of global variables, 1011** setting up a default [sqlite3_vfs] module, or setting up 1012** a default configuration using [sqlite3_config()]. 1013** 1014** The application should never invoke either sqlite3_os_init() 1015** or sqlite3_os_end() directly. The application should only invoke 1016** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1017** interface is called automatically by sqlite3_initialize() and 1018** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1019** implementations for sqlite3_os_init() and sqlite3_os_end() 1020** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1021** When [custom builds | built for other platforms] 1022** (using the [SQLITE_OS_OTHER=1] compile-time 1023** option) the application must supply a suitable implementation for 1024** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1025** implementation of sqlite3_os_init() or sqlite3_os_end() 1026** must return [SQLITE_OK] on success and some other [error code] upon 1027** failure. 1028*/ 1029int sqlite3_initialize(void); 1030int sqlite3_shutdown(void); 1031int sqlite3_os_init(void); 1032int sqlite3_os_end(void); 1033 1034/* 1035** CAPI3REF: Configuring The SQLite Library 1036** 1037** The sqlite3_config() interface is used to make global configuration 1038** changes to SQLite in order to tune SQLite to the specific needs of 1039** the application. The default configuration is recommended for most 1040** applications and so this routine is usually not necessary. It is 1041** provided to support rare applications with unusual needs. 1042** 1043** The sqlite3_config() interface is not threadsafe. The application 1044** must insure that no other SQLite interfaces are invoked by other 1045** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1046** may only be invoked prior to library initialization using 1047** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1048** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1049** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1050** Note, however, that ^sqlite3_config() can be called as part of the 1051** implementation of an application-defined [sqlite3_os_init()]. 1052** 1053** The first argument to sqlite3_config() is an integer 1054** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines 1055** what property of SQLite is to be configured. Subsequent arguments 1056** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option] 1057** in the first argument. 1058** 1059** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1060** ^If the option is unknown or SQLite is unable to set the option 1061** then this routine returns a non-zero [error code]. 1062*/ 1063int sqlite3_config(int, ...); 1064 1065/* 1066** CAPI3REF: Configure database connections 1067** 1068** The sqlite3_db_config() interface is used to make configuration 1069** changes to a [database connection]. The interface is similar to 1070** [sqlite3_config()] except that the changes apply to a single 1071** [database connection] (specified in the first argument). The 1072** sqlite3_db_config() interface should only be used immediately after 1073** the database connection is created using [sqlite3_open()], 1074** [sqlite3_open16()], or [sqlite3_open_v2()]. 1075** 1076** The second argument to sqlite3_db_config(D,V,...) is the 1077** configuration verb - an integer code that indicates what 1078** aspect of the [database connection] is being configured. 1079** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE]. 1080** New verbs are likely to be added in future releases of SQLite. 1081** Additional arguments depend on the verb. 1082** 1083** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1084** the call is considered successful. 1085*/ 1086int sqlite3_db_config(sqlite3*, int op, ...); 1087 1088/* 1089** CAPI3REF: Memory Allocation Routines 1090** 1091** An instance of this object defines the interface between SQLite 1092** and low-level memory allocation routines. 1093** 1094** This object is used in only one place in the SQLite interface. 1095** A pointer to an instance of this object is the argument to 1096** [sqlite3_config()] when the configuration option is 1097** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1098** By creating an instance of this object 1099** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1100** during configuration, an application can specify an alternative 1101** memory allocation subsystem for SQLite to use for all of its 1102** dynamic memory needs. 1103** 1104** Note that SQLite comes with several [built-in memory allocators] 1105** that are perfectly adequate for the overwhelming majority of applications 1106** and that this object is only useful to a tiny minority of applications 1107** with specialized memory allocation requirements. This object is 1108** also used during testing of SQLite in order to specify an alternative 1109** memory allocator that simulates memory out-of-memory conditions in 1110** order to verify that SQLite recovers gracefully from such 1111** conditions. 1112** 1113** The xMalloc and xFree methods must work like the 1114** malloc() and free() functions from the standard C library. 1115** The xRealloc method must work like realloc() from the standard C library 1116** with the exception that if the second argument to xRealloc is zero, 1117** xRealloc must be a no-op - it must not perform any allocation or 1118** deallocation. ^SQLite guarantees that the second argument to 1119** xRealloc is always a value returned by a prior call to xRoundup. 1120** And so in cases where xRoundup always returns a positive number, 1121** xRealloc can perform exactly as the standard library realloc() and 1122** still be in compliance with this specification. 1123** 1124** xSize should return the allocated size of a memory allocation 1125** previously obtained from xMalloc or xRealloc. The allocated size 1126** is always at least as big as the requested size but may be larger. 1127** 1128** The xRoundup method returns what would be the allocated size of 1129** a memory allocation given a particular requested size. Most memory 1130** allocators round up memory allocations at least to the next multiple 1131** of 8. Some allocators round up to a larger multiple or to a power of 2. 1132** Every memory allocation request coming in through [sqlite3_malloc()] 1133** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1134** that causes the corresponding memory allocation to fail. 1135** 1136** The xInit method initializes the memory allocator. (For example, 1137** it might allocate any require mutexes or initialize internal data 1138** structures. The xShutdown method is invoked (indirectly) by 1139** [sqlite3_shutdown()] and should deallocate any resources acquired 1140** by xInit. The pAppData pointer is used as the only parameter to 1141** xInit and xShutdown. 1142** 1143** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1144** the xInit method, so the xInit method need not be threadsafe. The 1145** xShutdown method is only called from [sqlite3_shutdown()] so it does 1146** not need to be threadsafe either. For all other methods, SQLite 1147** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1148** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1149** it is by default) and so the methods are automatically serialized. 1150** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1151** methods must be threadsafe or else make their own arrangements for 1152** serialization. 1153** 1154** SQLite will never invoke xInit() more than once without an intervening 1155** call to xShutdown(). 1156*/ 1157typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1158struct sqlite3_mem_methods { 1159 void *(*xMalloc)(int); /* Memory allocation function */ 1160 void (*xFree)(void*); /* Free a prior allocation */ 1161 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1162 int (*xSize)(void*); /* Return the size of an allocation */ 1163 int (*xRoundup)(int); /* Round up request size to allocation size */ 1164 int (*xInit)(void*); /* Initialize the memory allocator */ 1165 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1166 void *pAppData; /* Argument to xInit() and xShutdown() */ 1167}; 1168 1169/* 1170** CAPI3REF: Configuration Options 1171** 1172** These constants are the available integer configuration options that 1173** can be passed as the first argument to the [sqlite3_config()] interface. 1174** 1175** New configuration options may be added in future releases of SQLite. 1176** Existing configuration options might be discontinued. Applications 1177** should check the return code from [sqlite3_config()] to make sure that 1178** the call worked. The [sqlite3_config()] interface will return a 1179** non-zero [error code] if a discontinued or unsupported configuration option 1180** is invoked. 1181** 1182** <dl> 1183** <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1184** <dd>There are no arguments to this option. ^This option sets the 1185** [threading mode] to Single-thread. In other words, it disables 1186** all mutexing and puts SQLite into a mode where it can only be used 1187** by a single thread. ^If SQLite is compiled with 1188** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1189** it is not possible to change the [threading mode] from its default 1190** value of Single-thread and so [sqlite3_config()] will return 1191** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1192** configuration option.</dd> 1193** 1194** <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1195** <dd>There are no arguments to this option. ^This option sets the 1196** [threading mode] to Multi-thread. In other words, it disables 1197** mutexing on [database connection] and [prepared statement] objects. 1198** The application is responsible for serializing access to 1199** [database connections] and [prepared statements]. But other mutexes 1200** are enabled so that SQLite will be safe to use in a multi-threaded 1201** environment as long as no two threads attempt to use the same 1202** [database connection] at the same time. ^If SQLite is compiled with 1203** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1204** it is not possible to set the Multi-thread [threading mode] and 1205** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1206** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1207** 1208** <dt>SQLITE_CONFIG_SERIALIZED</dt> 1209** <dd>There are no arguments to this option. ^This option sets the 1210** [threading mode] to Serialized. In other words, this option enables 1211** all mutexes including the recursive 1212** mutexes on [database connection] and [prepared statement] objects. 1213** In this mode (which is the default when SQLite is compiled with 1214** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1215** to [database connections] and [prepared statements] so that the 1216** application is free to use the same [database connection] or the 1217** same [prepared statement] in different threads at the same time. 1218** ^If SQLite is compiled with 1219** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1220** it is not possible to set the Serialized [threading mode] and 1221** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1222** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1223** 1224** <dt>SQLITE_CONFIG_MALLOC</dt> 1225** <dd> ^(This option takes a single argument which is a pointer to an 1226** instance of the [sqlite3_mem_methods] structure. The argument specifies 1227** alternative low-level memory allocation routines to be used in place of 1228** the memory allocation routines built into SQLite.)^ ^SQLite makes 1229** its own private copy of the content of the [sqlite3_mem_methods] structure 1230** before the [sqlite3_config()] call returns.</dd> 1231** 1232** <dt>SQLITE_CONFIG_GETMALLOC</dt> 1233** <dd> ^(This option takes a single argument which is a pointer to an 1234** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1235** structure is filled with the currently defined memory allocation routines.)^ 1236** This option can be used to overload the default memory allocation 1237** routines with a wrapper that simulations memory allocation failure or 1238** tracks memory usage, for example. </dd> 1239** 1240** <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1241** <dd> ^This option takes single argument of type int, interpreted as a 1242** boolean, which enables or disables the collection of memory allocation 1243** statistics. ^(When memory allocation statistics are disabled, the 1244** following SQLite interfaces become non-operational: 1245** <ul> 1246** <li> [sqlite3_memory_used()] 1247** <li> [sqlite3_memory_highwater()] 1248** <li> [sqlite3_soft_heap_limit()] 1249** <li> [sqlite3_status()] 1250** </ul>)^ 1251** ^Memory allocation statistics are enabled by default unless SQLite is 1252** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1253** allocation statistics are disabled by default. 1254** </dd> 1255** 1256** <dt>SQLITE_CONFIG_SCRATCH</dt> 1257** <dd> ^This option specifies a static memory buffer that SQLite can use for 1258** scratch memory. There are three arguments: A pointer an 8-byte 1259** aligned memory buffer from which the scrach allocations will be 1260** drawn, the size of each scratch allocation (sz), 1261** and the maximum number of scratch allocations (N). The sz 1262** argument must be a multiple of 16. 1263** The first argument must be a pointer to an 8-byte aligned buffer 1264** of at least sz*N bytes of memory. 1265** ^SQLite will use no more than two scratch buffers per thread. So 1266** N should be set to twice the expected maximum number of threads. 1267** ^SQLite will never require a scratch buffer that is more than 6 1268** times the database page size. ^If SQLite needs needs additional 1269** scratch memory beyond what is provided by this configuration option, then 1270** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1271** 1272** <dt>SQLITE_CONFIG_PAGECACHE</dt> 1273** <dd> ^This option specifies a static memory buffer that SQLite can use for 1274** the database page cache with the default page cache implemenation. 1275** This configuration should not be used if an application-define page 1276** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option. 1277** There are three arguments to this option: A pointer to 8-byte aligned 1278** memory, the size of each page buffer (sz), and the number of pages (N). 1279** The sz argument should be the size of the largest database page 1280** (a power of two between 512 and 32768) plus a little extra for each 1281** page header. ^The page header size is 20 to 40 bytes depending on 1282** the host architecture. ^It is harmless, apart from the wasted memory, 1283** to make sz a little too large. The first 1284** argument should point to an allocation of at least sz*N bytes of memory. 1285** ^SQLite will use the memory provided by the first argument to satisfy its 1286** memory needs for the first N pages that it adds to cache. ^If additional 1287** page cache memory is needed beyond what is provided by this option, then 1288** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1289** The pointer in the first argument must 1290** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1291** will be undefined.</dd> 1292** 1293** <dt>SQLITE_CONFIG_HEAP</dt> 1294** <dd> ^This option specifies a static memory buffer that SQLite will use 1295** for all of its dynamic memory allocation needs beyond those provided 1296** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1297** There are three arguments: An 8-byte aligned pointer to the memory, 1298** the number of bytes in the memory buffer, and the minimum allocation size. 1299** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1300** to using its default memory allocator (the system malloc() implementation), 1301** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1302** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1303** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1304** allocator is engaged to handle all of SQLites memory allocation needs. 1305** The first pointer (the memory pointer) must be aligned to an 8-byte 1306** boundary or subsequent behavior of SQLite will be undefined.</dd> 1307** 1308** <dt>SQLITE_CONFIG_MUTEX</dt> 1309** <dd> ^(This option takes a single argument which is a pointer to an 1310** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1311** alternative low-level mutex routines to be used in place 1312** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1313** content of the [sqlite3_mutex_methods] structure before the call to 1314** [sqlite3_config()] returns. ^If SQLite is compiled with 1315** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1316** the entire mutexing subsystem is omitted from the build and hence calls to 1317** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1318** return [SQLITE_ERROR].</dd> 1319** 1320** <dt>SQLITE_CONFIG_GETMUTEX</dt> 1321** <dd> ^(This option takes a single argument which is a pointer to an 1322** instance of the [sqlite3_mutex_methods] structure. The 1323** [sqlite3_mutex_methods] 1324** structure is filled with the currently defined mutex routines.)^ 1325** This option can be used to overload the default mutex allocation 1326** routines with a wrapper used to track mutex usage for performance 1327** profiling or testing, for example. ^If SQLite is compiled with 1328** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1329** the entire mutexing subsystem is omitted from the build and hence calls to 1330** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1331** return [SQLITE_ERROR].</dd> 1332** 1333** <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1334** <dd> ^(This option takes two arguments that determine the default 1335** memory allocation for the lookaside memory allocator on each 1336** [database connection]. The first argument is the 1337** size of each lookaside buffer slot and the second is the number of 1338** slots allocated to each database connection.)^ ^(This option sets the 1339** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1340** verb to [sqlite3_db_config()] can be used to change the lookaside 1341** configuration on individual connections.)^ </dd> 1342** 1343** <dt>SQLITE_CONFIG_PCACHE</dt> 1344** <dd> ^(This option takes a single argument which is a pointer to 1345** an [sqlite3_pcache_methods] object. This object specifies the interface 1346** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1347** object and uses it for page cache memory allocations.</dd> 1348** 1349** <dt>SQLITE_CONFIG_GETPCACHE</dt> 1350** <dd> ^(This option takes a single argument which is a pointer to an 1351** [sqlite3_pcache_methods] object. SQLite copies of the current 1352** page cache implementation into that object.)^ </dd> 1353** 1354** <dt>SQLITE_CONFIG_LOG</dt> 1355** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1356** function with a call signature of void(*)(void*,int,const char*), 1357** and a pointer to void. ^If the function pointer is not NULL, it is 1358** invoked by [sqlite3_log()] to process each logging event. ^If the 1359** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1360** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1361** passed through as the first parameter to the application-defined logger 1362** function whenever that function is invoked. ^The second parameter to 1363** the logger function is a copy of the first parameter to the corresponding 1364** [sqlite3_log()] call and is intended to be a [result code] or an 1365** [extended result code]. ^The third parameter passed to the logger is 1366** log message after formatting via [sqlite3_snprintf()]. 1367** The SQLite logging interface is not reentrant; the logger function 1368** supplied by the application must not invoke any SQLite interface. 1369** In a multi-threaded application, the application-defined logger 1370** function must be threadsafe. </dd> 1371** 1372** </dl> 1373*/ 1374#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1375#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1376#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1377#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1378#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1379#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1380#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1381#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1382#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1383#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1384#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1385/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1386#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1387#define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */ 1388#define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */ 1389#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1390 1391/* 1392** CAPI3REF: Database Connection Configuration Options 1393** 1394** These constants are the available integer configuration options that 1395** can be passed as the second argument to the [sqlite3_db_config()] interface. 1396** 1397** New configuration options may be added in future releases of SQLite. 1398** Existing configuration options might be discontinued. Applications 1399** should check the return code from [sqlite3_db_config()] to make sure that 1400** the call worked. ^The [sqlite3_db_config()] interface will return a 1401** non-zero [error code] if a discontinued or unsupported configuration option 1402** is invoked. 1403** 1404** <dl> 1405** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1406** <dd> ^This option takes three additional arguments that determine the 1407** [lookaside memory allocator] configuration for the [database connection]. 1408** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1409** pointer to an memory buffer to use for lookaside memory. 1410** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1411** may be NULL in which case SQLite will allocate the 1412** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1413** size of each lookaside buffer slot. ^The third argument is the number of 1414** slots. The size of the buffer in the first argument must be greater than 1415** or equal to the product of the second and third arguments. The buffer 1416** must be aligned to an 8-byte boundary. ^If the second argument to 1417** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1418** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1419** configuration for a database connection can only be changed when that 1420** connection is not currently using lookaside memory, or in other words 1421** when the "current value" returned by 1422** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1423** Any attempt to change the lookaside memory configuration when lookaside 1424** memory is in use leaves the configuration unchanged and returns 1425** [SQLITE_BUSY].)^</dd> 1426** 1427** </dl> 1428*/ 1429#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1430 1431 1432/* 1433** CAPI3REF: Enable Or Disable Extended Result Codes 1434** 1435** ^The sqlite3_extended_result_codes() routine enables or disables the 1436** [extended result codes] feature of SQLite. ^The extended result 1437** codes are disabled by default for historical compatibility. 1438*/ 1439int sqlite3_extended_result_codes(sqlite3*, int onoff); 1440 1441/* 1442** CAPI3REF: Last Insert Rowid 1443** 1444** ^Each entry in an SQLite table has a unique 64-bit signed 1445** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1446** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1447** names are not also used by explicitly declared columns. ^If 1448** the table has a column of type [INTEGER PRIMARY KEY] then that column 1449** is another alias for the rowid. 1450** 1451** ^This routine returns the [rowid] of the most recent 1452** successful [INSERT] into the database from the [database connection] 1453** in the first argument. ^If no successful [INSERT]s 1454** have ever occurred on that database connection, zero is returned. 1455** 1456** ^(If an [INSERT] occurs within a trigger, then the [rowid] of the inserted 1457** row is returned by this routine as long as the trigger is running. 1458** But once the trigger terminates, the value returned by this routine 1459** reverts to the last value inserted before the trigger fired.)^ 1460** 1461** ^An [INSERT] that fails due to a constraint violation is not a 1462** successful [INSERT] and does not change the value returned by this 1463** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1464** and INSERT OR ABORT make no changes to the return value of this 1465** routine when their insertion fails. ^(When INSERT OR REPLACE 1466** encounters a constraint violation, it does not fail. The 1467** INSERT continues to completion after deleting rows that caused 1468** the constraint problem so INSERT OR REPLACE will always change 1469** the return value of this interface.)^ 1470** 1471** ^For the purposes of this routine, an [INSERT] is considered to 1472** be successful even if it is subsequently rolled back. 1473** 1474** This function is accessible to SQL statements via the 1475** [last_insert_rowid() SQL function]. 1476** 1477** If a separate thread performs a new [INSERT] on the same 1478** database connection while the [sqlite3_last_insert_rowid()] 1479** function is running and thus changes the last insert [rowid], 1480** then the value returned by [sqlite3_last_insert_rowid()] is 1481** unpredictable and might not equal either the old or the new 1482** last insert [rowid]. 1483*/ 1484sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1485 1486/* 1487** CAPI3REF: Count The Number Of Rows Modified 1488** 1489** ^This function returns the number of database rows that were changed 1490** or inserted or deleted by the most recently completed SQL statement 1491** on the [database connection] specified by the first parameter. 1492** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1493** or [DELETE] statement are counted. Auxiliary changes caused by 1494** triggers or [foreign key actions] are not counted.)^ Use the 1495** [sqlite3_total_changes()] function to find the total number of changes 1496** including changes caused by triggers and foreign key actions. 1497** 1498** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1499** are not counted. Only real table changes are counted. 1500** 1501** ^(A "row change" is a change to a single row of a single table 1502** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1503** are changed as side effects of [REPLACE] constraint resolution, 1504** rollback, ABORT processing, [DROP TABLE], or by any other 1505** mechanisms do not count as direct row changes.)^ 1506** 1507** A "trigger context" is a scope of execution that begins and 1508** ends with the script of a [CREATE TRIGGER | trigger]. 1509** Most SQL statements are 1510** evaluated outside of any trigger. This is the "top level" 1511** trigger context. If a trigger fires from the top level, a 1512** new trigger context is entered for the duration of that one 1513** trigger. Subtriggers create subcontexts for their duration. 1514** 1515** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1516** not create a new trigger context. 1517** 1518** ^This function returns the number of direct row changes in the 1519** most recent INSERT, UPDATE, or DELETE statement within the same 1520** trigger context. 1521** 1522** ^Thus, when called from the top level, this function returns the 1523** number of changes in the most recent INSERT, UPDATE, or DELETE 1524** that also occurred at the top level. ^(Within the body of a trigger, 1525** the sqlite3_changes() interface can be called to find the number of 1526** changes in the most recently completed INSERT, UPDATE, or DELETE 1527** statement within the body of the same trigger. 1528** However, the number returned does not include changes 1529** caused by subtriggers since those have their own context.)^ 1530** 1531** See also the [sqlite3_total_changes()] interface, the 1532** [count_changes pragma], and the [changes() SQL function]. 1533** 1534** If a separate thread makes changes on the same database connection 1535** while [sqlite3_changes()] is running then the value returned 1536** is unpredictable and not meaningful. 1537*/ 1538int sqlite3_changes(sqlite3*); 1539 1540/* 1541** CAPI3REF: Total Number Of Rows Modified 1542** 1543** ^This function returns the number of row changes caused by [INSERT], 1544** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1545** ^(The count returned by sqlite3_total_changes() includes all changes 1546** from all [CREATE TRIGGER | trigger] contexts and changes made by 1547** [foreign key actions]. However, 1548** the count does not include changes used to implement [REPLACE] constraints, 1549** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1550** count does not include rows of views that fire an [INSTEAD OF trigger], 1551** though if the INSTEAD OF trigger makes changes of its own, those changes 1552** are counted.)^ 1553** ^The sqlite3_total_changes() function counts the changes as soon as 1554** the statement that makes them is completed (when the statement handle 1555** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1556** 1557** See also the [sqlite3_changes()] interface, the 1558** [count_changes pragma], and the [total_changes() SQL function]. 1559** 1560** If a separate thread makes changes on the same database connection 1561** while [sqlite3_total_changes()] is running then the value 1562** returned is unpredictable and not meaningful. 1563*/ 1564int sqlite3_total_changes(sqlite3*); 1565 1566/* 1567** CAPI3REF: Interrupt A Long-Running Query 1568** 1569** ^This function causes any pending database operation to abort and 1570** return at its earliest opportunity. This routine is typically 1571** called in response to a user action such as pressing "Cancel" 1572** or Ctrl-C where the user wants a long query operation to halt 1573** immediately. 1574** 1575** ^It is safe to call this routine from a thread different from the 1576** thread that is currently running the database operation. But it 1577** is not safe to call this routine with a [database connection] that 1578** is closed or might close before sqlite3_interrupt() returns. 1579** 1580** ^If an SQL operation is very nearly finished at the time when 1581** sqlite3_interrupt() is called, then it might not have an opportunity 1582** to be interrupted and might continue to completion. 1583** 1584** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1585** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1586** that is inside an explicit transaction, then the entire transaction 1587** will be rolled back automatically. 1588** 1589** ^The sqlite3_interrupt(D) call is in effect until all currently running 1590** SQL statements on [database connection] D complete. ^Any new SQL statements 1591** that are started after the sqlite3_interrupt() call and before the 1592** running statements reaches zero are interrupted as if they had been 1593** running prior to the sqlite3_interrupt() call. ^New SQL statements 1594** that are started after the running statement count reaches zero are 1595** not effected by the sqlite3_interrupt(). 1596** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1597** SQL statements is a no-op and has no effect on SQL statements 1598** that are started after the sqlite3_interrupt() call returns. 1599** 1600** If the database connection closes while [sqlite3_interrupt()] 1601** is running then bad things will likely happen. 1602*/ 1603void sqlite3_interrupt(sqlite3*); 1604 1605/* 1606** CAPI3REF: Determine If An SQL Statement Is Complete 1607** 1608** These routines are useful during command-line input to determine if the 1609** currently entered text seems to form a complete SQL statement or 1610** if additional input is needed before sending the text into 1611** SQLite for parsing. ^These routines return 1 if the input string 1612** appears to be a complete SQL statement. ^A statement is judged to be 1613** complete if it ends with a semicolon token and is not a prefix of a 1614** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1615** string literals or quoted identifier names or comments are not 1616** independent tokens (they are part of the token in which they are 1617** embedded) and thus do not count as a statement terminator. ^Whitespace 1618** and comments that follow the final semicolon are ignored. 1619** 1620** ^These routines return 0 if the statement is incomplete. ^If a 1621** memory allocation fails, then SQLITE_NOMEM is returned. 1622** 1623** ^These routines do not parse the SQL statements thus 1624** will not detect syntactically incorrect SQL. 1625** 1626** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1627** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1628** automatically by sqlite3_complete16(). If that initialization fails, 1629** then the return value from sqlite3_complete16() will be non-zero 1630** regardless of whether or not the input SQL is complete.)^ 1631** 1632** The input to [sqlite3_complete()] must be a zero-terminated 1633** UTF-8 string. 1634** 1635** The input to [sqlite3_complete16()] must be a zero-terminated 1636** UTF-16 string in native byte order. 1637*/ 1638int sqlite3_complete(const char *sql); 1639int sqlite3_complete16(const void *sql); 1640 1641/* 1642** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1643** 1644** ^This routine sets a callback function that might be invoked whenever 1645** an attempt is made to open a database table that another thread 1646** or process has locked. 1647** 1648** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1649** is returned immediately upon encountering the lock. ^If the busy callback 1650** is not NULL, then the callback might be invoked with two arguments. 1651** 1652** ^The first argument to the busy handler is a copy of the void* pointer which 1653** is the third argument to sqlite3_busy_handler(). ^The second argument to 1654** the busy handler callback is the number of times that the busy handler has 1655** been invoked for this locking event. ^If the 1656** busy callback returns 0, then no additional attempts are made to 1657** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1658** ^If the callback returns non-zero, then another attempt 1659** is made to open the database for reading and the cycle repeats. 1660** 1661** The presence of a busy handler does not guarantee that it will be invoked 1662** when there is lock contention. ^If SQLite determines that invoking the busy 1663** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1664** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1665** Consider a scenario where one process is holding a read lock that 1666** it is trying to promote to a reserved lock and 1667** a second process is holding a reserved lock that it is trying 1668** to promote to an exclusive lock. The first process cannot proceed 1669** because it is blocked by the second and the second process cannot 1670** proceed because it is blocked by the first. If both processes 1671** invoke the busy handlers, neither will make any progress. Therefore, 1672** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1673** will induce the first process to release its read lock and allow 1674** the second process to proceed. 1675** 1676** ^The default busy callback is NULL. 1677** 1678** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1679** when SQLite is in the middle of a large transaction where all the 1680** changes will not fit into the in-memory cache. SQLite will 1681** already hold a RESERVED lock on the database file, but it needs 1682** to promote this lock to EXCLUSIVE so that it can spill cache 1683** pages into the database file without harm to concurrent 1684** readers. ^If it is unable to promote the lock, then the in-memory 1685** cache will be left in an inconsistent state and so the error 1686** code is promoted from the relatively benign [SQLITE_BUSY] to 1687** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 1688** forces an automatic rollback of the changes. See the 1689** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1690** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1691** this is important. 1692** 1693** ^(There can only be a single busy handler defined for each 1694** [database connection]. Setting a new busy handler clears any 1695** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 1696** will also set or clear the busy handler. 1697** 1698** The busy callback should not take any actions which modify the 1699** database connection that invoked the busy handler. Any such actions 1700** result in undefined behavior. 1701** 1702** A busy handler must not close the database connection 1703** or [prepared statement] that invoked the busy handler. 1704*/ 1705int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1706 1707/* 1708** CAPI3REF: Set A Busy Timeout 1709** 1710** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1711** for a specified amount of time when a table is locked. ^The handler 1712** will sleep multiple times until at least "ms" milliseconds of sleeping 1713** have accumulated. ^After at least "ms" milliseconds of sleeping, 1714** the handler returns 0 which causes [sqlite3_step()] to return 1715** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1716** 1717** ^Calling this routine with an argument less than or equal to zero 1718** turns off all busy handlers. 1719** 1720** ^(There can only be a single busy handler for a particular 1721** [database connection] any any given moment. If another busy handler 1722** was defined (using [sqlite3_busy_handler()]) prior to calling 1723** this routine, that other busy handler is cleared.)^ 1724*/ 1725int sqlite3_busy_timeout(sqlite3*, int ms); 1726 1727/* 1728** CAPI3REF: Convenience Routines For Running Queries 1729** 1730** Definition: A <b>result table</b> is memory data structure created by the 1731** [sqlite3_get_table()] interface. A result table records the 1732** complete query results from one or more queries. 1733** 1734** The table conceptually has a number of rows and columns. But 1735** these numbers are not part of the result table itself. These 1736** numbers are obtained separately. Let N be the number of rows 1737** and M be the number of columns. 1738** 1739** A result table is an array of pointers to zero-terminated UTF-8 strings. 1740** There are (N+1)*M elements in the array. The first M pointers point 1741** to zero-terminated strings that contain the names of the columns. 1742** The remaining entries all point to query results. NULL values result 1743** in NULL pointers. All other values are in their UTF-8 zero-terminated 1744** string representation as returned by [sqlite3_column_text()]. 1745** 1746** A result table might consist of one or more memory allocations. 1747** It is not safe to pass a result table directly to [sqlite3_free()]. 1748** A result table should be deallocated using [sqlite3_free_table()]. 1749** 1750** As an example of the result table format, suppose a query result 1751** is as follows: 1752** 1753** <blockquote><pre> 1754** Name | Age 1755** ----------------------- 1756** Alice | 43 1757** Bob | 28 1758** Cindy | 21 1759** </pre></blockquote> 1760** 1761** There are two column (M==2) and three rows (N==3). Thus the 1762** result table has 8 entries. Suppose the result table is stored 1763** in an array names azResult. Then azResult holds this content: 1764** 1765** <blockquote><pre> 1766** azResult[0] = "Name"; 1767** azResult[1] = "Age"; 1768** azResult[2] = "Alice"; 1769** azResult[3] = "43"; 1770** azResult[4] = "Bob"; 1771** azResult[5] = "28"; 1772** azResult[6] = "Cindy"; 1773** azResult[7] = "21"; 1774** </pre></blockquote> 1775** 1776** ^The sqlite3_get_table() function evaluates one or more 1777** semicolon-separated SQL statements in the zero-terminated UTF-8 1778** string of its 2nd parameter and returns a result table to the 1779** pointer given in its 3rd parameter. 1780** 1781** After the application has finished with the result from sqlite3_get_table(), 1782** it should pass the result table pointer to sqlite3_free_table() in order to 1783** release the memory that was malloced. Because of the way the 1784** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1785** function must not try to call [sqlite3_free()] directly. Only 1786** [sqlite3_free_table()] is able to release the memory properly and safely. 1787** 1788** ^(The sqlite3_get_table() interface is implemented as a wrapper around 1789** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 1790** to any internal data structures of SQLite. It uses only the public 1791** interface defined here. As a consequence, errors that occur in the 1792** wrapper layer outside of the internal [sqlite3_exec()] call are not 1793** reflected in subsequent calls to [sqlite3_errcode()] or 1794** [sqlite3_errmsg()].)^ 1795*/ 1796int sqlite3_get_table( 1797 sqlite3 *db, /* An open database */ 1798 const char *zSql, /* SQL to be evaluated */ 1799 char ***pazResult, /* Results of the query */ 1800 int *pnRow, /* Number of result rows written here */ 1801 int *pnColumn, /* Number of result columns written here */ 1802 char **pzErrmsg /* Error msg written here */ 1803); 1804void sqlite3_free_table(char **result); 1805 1806/* 1807** CAPI3REF: Formatted String Printing Functions 1808** 1809** These routines are work-alikes of the "printf()" family of functions 1810** from the standard C library. 1811** 1812** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 1813** results into memory obtained from [sqlite3_malloc()]. 1814** The strings returned by these two routines should be 1815** released by [sqlite3_free()]. ^Both routines return a 1816** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 1817** memory to hold the resulting string. 1818** 1819** ^(In sqlite3_snprintf() routine is similar to "snprintf()" from 1820** the standard C library. The result is written into the 1821** buffer supplied as the second parameter whose size is given by 1822** the first parameter. Note that the order of the 1823** first two parameters is reversed from snprintf().)^ This is an 1824** historical accident that cannot be fixed without breaking 1825** backwards compatibility. ^(Note also that sqlite3_snprintf() 1826** returns a pointer to its buffer instead of the number of 1827** characters actually written into the buffer.)^ We admit that 1828** the number of characters written would be a more useful return 1829** value but we cannot change the implementation of sqlite3_snprintf() 1830** now without breaking compatibility. 1831** 1832** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 1833** guarantees that the buffer is always zero-terminated. ^The first 1834** parameter "n" is the total size of the buffer, including space for 1835** the zero terminator. So the longest string that can be completely 1836** written will be n-1 characters. 1837** 1838** These routines all implement some additional formatting 1839** options that are useful for constructing SQL statements. 1840** All of the usual printf() formatting options apply. In addition, there 1841** is are "%q", "%Q", and "%z" options. 1842** 1843** ^(The %q option works like %s in that it substitutes a null-terminated 1844** string from the argument list. But %q also doubles every '\'' character. 1845** %q is designed for use inside a string literal.)^ By doubling each '\'' 1846** character it escapes that character and allows it to be inserted into 1847** the string. 1848** 1849** For example, assume the string variable zText contains text as follows: 1850** 1851** <blockquote><pre> 1852** char *zText = "It's a happy day!"; 1853** </pre></blockquote> 1854** 1855** One can use this text in an SQL statement as follows: 1856** 1857** <blockquote><pre> 1858** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 1859** sqlite3_exec(db, zSQL, 0, 0, 0); 1860** sqlite3_free(zSQL); 1861** </pre></blockquote> 1862** 1863** Because the %q format string is used, the '\'' character in zText 1864** is escaped and the SQL generated is as follows: 1865** 1866** <blockquote><pre> 1867** INSERT INTO table1 VALUES('It''s a happy day!') 1868** </pre></blockquote> 1869** 1870** This is correct. Had we used %s instead of %q, the generated SQL 1871** would have looked like this: 1872** 1873** <blockquote><pre> 1874** INSERT INTO table1 VALUES('It's a happy day!'); 1875** </pre></blockquote> 1876** 1877** This second example is an SQL syntax error. As a general rule you should 1878** always use %q instead of %s when inserting text into a string literal. 1879** 1880** ^(The %Q option works like %q except it also adds single quotes around 1881** the outside of the total string. Additionally, if the parameter in the 1882** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 1883** single quotes).)^ So, for example, one could say: 1884** 1885** <blockquote><pre> 1886** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 1887** sqlite3_exec(db, zSQL, 0, 0, 0); 1888** sqlite3_free(zSQL); 1889** </pre></blockquote> 1890** 1891** The code above will render a correct SQL statement in the zSQL 1892** variable even if the zText variable is a NULL pointer. 1893** 1894** ^(The "%z" formatting option works like "%s" but with the 1895** addition that after the string has been read and copied into 1896** the result, [sqlite3_free()] is called on the input string.)^ 1897*/ 1898char *sqlite3_mprintf(const char*,...); 1899char *sqlite3_vmprintf(const char*, va_list); 1900char *sqlite3_snprintf(int,char*,const char*, ...); 1901 1902/* 1903** CAPI3REF: Memory Allocation Subsystem 1904** 1905** The SQLite core uses these three routines for all of its own 1906** internal memory allocation needs. "Core" in the previous sentence 1907** does not include operating-system specific VFS implementation. The 1908** Windows VFS uses native malloc() and free() for some operations. 1909** 1910** ^The sqlite3_malloc() routine returns a pointer to a block 1911** of memory at least N bytes in length, where N is the parameter. 1912** ^If sqlite3_malloc() is unable to obtain sufficient free 1913** memory, it returns a NULL pointer. ^If the parameter N to 1914** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 1915** a NULL pointer. 1916** 1917** ^Calling sqlite3_free() with a pointer previously returned 1918** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 1919** that it might be reused. ^The sqlite3_free() routine is 1920** a no-op if is called with a NULL pointer. Passing a NULL pointer 1921** to sqlite3_free() is harmless. After being freed, memory 1922** should neither be read nor written. Even reading previously freed 1923** memory might result in a segmentation fault or other severe error. 1924** Memory corruption, a segmentation fault, or other severe error 1925** might result if sqlite3_free() is called with a non-NULL pointer that 1926** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 1927** 1928** ^(The sqlite3_realloc() interface attempts to resize a 1929** prior memory allocation to be at least N bytes, where N is the 1930** second parameter. The memory allocation to be resized is the first 1931** parameter.)^ ^ If the first parameter to sqlite3_realloc() 1932** is a NULL pointer then its behavior is identical to calling 1933** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 1934** ^If the second parameter to sqlite3_realloc() is zero or 1935** negative then the behavior is exactly the same as calling 1936** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 1937** ^sqlite3_realloc() returns a pointer to a memory allocation 1938** of at least N bytes in size or NULL if sufficient memory is unavailable. 1939** ^If M is the size of the prior allocation, then min(N,M) bytes 1940** of the prior allocation are copied into the beginning of buffer returned 1941** by sqlite3_realloc() and the prior allocation is freed. 1942** ^If sqlite3_realloc() returns NULL, then the prior allocation 1943** is not freed. 1944** 1945** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 1946** is always aligned to at least an 8 byte boundary. 1947** 1948** In SQLite version 3.5.0 and 3.5.1, it was possible to define 1949** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 1950** implementation of these routines to be omitted. That capability 1951** is no longer provided. Only built-in memory allocators can be used. 1952** 1953** The Windows OS interface layer calls 1954** the system malloc() and free() directly when converting 1955** filenames between the UTF-8 encoding used by SQLite 1956** and whatever filename encoding is used by the particular Windows 1957** installation. Memory allocation errors are detected, but 1958** they are reported back as [SQLITE_CANTOPEN] or 1959** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 1960** 1961** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 1962** must be either NULL or else pointers obtained from a prior 1963** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 1964** not yet been released. 1965** 1966** The application must not read or write any part of 1967** a block of memory after it has been released using 1968** [sqlite3_free()] or [sqlite3_realloc()]. 1969*/ 1970void *sqlite3_malloc(int); 1971void *sqlite3_realloc(void*, int); 1972void sqlite3_free(void*); 1973 1974/* 1975** CAPI3REF: Memory Allocator Statistics 1976** 1977** SQLite provides these two interfaces for reporting on the status 1978** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 1979** routines, which form the built-in memory allocation subsystem. 1980** 1981** ^The [sqlite3_memory_used()] routine returns the number of bytes 1982** of memory currently outstanding (malloced but not freed). 1983** ^The [sqlite3_memory_highwater()] routine returns the maximum 1984** value of [sqlite3_memory_used()] since the high-water mark 1985** was last reset. ^The values returned by [sqlite3_memory_used()] and 1986** [sqlite3_memory_highwater()] include any overhead 1987** added by SQLite in its implementation of [sqlite3_malloc()], 1988** but not overhead added by the any underlying system library 1989** routines that [sqlite3_malloc()] may call. 1990** 1991** ^The memory high-water mark is reset to the current value of 1992** [sqlite3_memory_used()] if and only if the parameter to 1993** [sqlite3_memory_highwater()] is true. ^The value returned 1994** by [sqlite3_memory_highwater(1)] is the high-water mark 1995** prior to the reset. 1996*/ 1997sqlite3_int64 sqlite3_memory_used(void); 1998sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 1999 2000/* 2001** CAPI3REF: Pseudo-Random Number Generator 2002** 2003** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2004** select random [ROWID | ROWIDs] when inserting new records into a table that 2005** already uses the largest possible [ROWID]. The PRNG is also used for 2006** the build-in random() and randomblob() SQL functions. This interface allows 2007** applications to access the same PRNG for other purposes. 2008** 2009** ^A call to this routine stores N bytes of randomness into buffer P. 2010** 2011** ^The first time this routine is invoked (either internally or by 2012** the application) the PRNG is seeded using randomness obtained 2013** from the xRandomness method of the default [sqlite3_vfs] object. 2014** ^On all subsequent invocations, the pseudo-randomness is generated 2015** internally and without recourse to the [sqlite3_vfs] xRandomness 2016** method. 2017*/ 2018void sqlite3_randomness(int N, void *P); 2019 2020/* 2021** CAPI3REF: Compile-Time Authorization Callbacks 2022** 2023** ^This routine registers a authorizer callback with a particular 2024** [database connection], supplied in the first argument. 2025** ^The authorizer callback is invoked as SQL statements are being compiled 2026** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2027** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2028** points during the compilation process, as logic is being created 2029** to perform various actions, the authorizer callback is invoked to 2030** see if those actions are allowed. ^The authorizer callback should 2031** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2032** specific action but allow the SQL statement to continue to be 2033** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2034** rejected with an error. ^If the authorizer callback returns 2035** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2036** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2037** the authorizer will fail with an error message. 2038** 2039** When the callback returns [SQLITE_OK], that means the operation 2040** requested is ok. ^When the callback returns [SQLITE_DENY], the 2041** [sqlite3_prepare_v2()] or equivalent call that triggered the 2042** authorizer will fail with an error message explaining that 2043** access is denied. 2044** 2045** ^The first parameter to the authorizer callback is a copy of the third 2046** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2047** to the callback is an integer [SQLITE_COPY | action code] that specifies 2048** the particular action to be authorized. ^The third through sixth parameters 2049** to the callback are zero-terminated strings that contain additional 2050** details about the action to be authorized. 2051** 2052** ^If the action code is [SQLITE_READ] 2053** and the callback returns [SQLITE_IGNORE] then the 2054** [prepared statement] statement is constructed to substitute 2055** a NULL value in place of the table column that would have 2056** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2057** return can be used to deny an untrusted user access to individual 2058** columns of a table. 2059** ^If the action code is [SQLITE_DELETE] and the callback returns 2060** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2061** [truncate optimization] is disabled and all rows are deleted individually. 2062** 2063** An authorizer is used when [sqlite3_prepare | preparing] 2064** SQL statements from an untrusted source, to ensure that the SQL statements 2065** do not try to access data they are not allowed to see, or that they do not 2066** try to execute malicious statements that damage the database. For 2067** example, an application may allow a user to enter arbitrary 2068** SQL queries for evaluation by a database. But the application does 2069** not want the user to be able to make arbitrary changes to the 2070** database. An authorizer could then be put in place while the 2071** user-entered SQL is being [sqlite3_prepare | prepared] that 2072** disallows everything except [SELECT] statements. 2073** 2074** Applications that need to process SQL from untrusted sources 2075** might also consider lowering resource limits using [sqlite3_limit()] 2076** and limiting database size using the [max_page_count] [PRAGMA] 2077** in addition to using an authorizer. 2078** 2079** ^(Only a single authorizer can be in place on a database connection 2080** at a time. Each call to sqlite3_set_authorizer overrides the 2081** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2082** The authorizer is disabled by default. 2083** 2084** The authorizer callback must not do anything that will modify 2085** the database connection that invoked the authorizer callback. 2086** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2087** database connections for the meaning of "modify" in this paragraph. 2088** 2089** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2090** statement might be re-prepared during [sqlite3_step()] due to a 2091** schema change. Hence, the application should ensure that the 2092** correct authorizer callback remains in place during the [sqlite3_step()]. 2093** 2094** ^Note that the authorizer callback is invoked only during 2095** [sqlite3_prepare()] or its variants. Authorization is not 2096** performed during statement evaluation in [sqlite3_step()], unless 2097** as stated in the previous paragraph, sqlite3_step() invokes 2098** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2099*/ 2100int sqlite3_set_authorizer( 2101 sqlite3*, 2102 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2103 void *pUserData 2104); 2105 2106/* 2107** CAPI3REF: Authorizer Return Codes 2108** 2109** The [sqlite3_set_authorizer | authorizer callback function] must 2110** return either [SQLITE_OK] or one of these two constants in order 2111** to signal SQLite whether or not the action is permitted. See the 2112** [sqlite3_set_authorizer | authorizer documentation] for additional 2113** information. 2114*/ 2115#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2116#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2117 2118/* 2119** CAPI3REF: Authorizer Action Codes 2120** 2121** The [sqlite3_set_authorizer()] interface registers a callback function 2122** that is invoked to authorize certain SQL statement actions. The 2123** second parameter to the callback is an integer code that specifies 2124** what action is being authorized. These are the integer action codes that 2125** the authorizer callback may be passed. 2126** 2127** These action code values signify what kind of operation is to be 2128** authorized. The 3rd and 4th parameters to the authorization 2129** callback function will be parameters or NULL depending on which of these 2130** codes is used as the second parameter. ^(The 5th parameter to the 2131** authorizer callback is the name of the database ("main", "temp", 2132** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2133** is the name of the inner-most trigger or view that is responsible for 2134** the access attempt or NULL if this access attempt is directly from 2135** top-level SQL code. 2136*/ 2137/******************************************* 3rd ************ 4th ***********/ 2138#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2139#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2140#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2141#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2142#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2143#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2144#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2145#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2146#define SQLITE_DELETE 9 /* Table Name NULL */ 2147#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2148#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2149#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2150#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2151#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2152#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2153#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2154#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2155#define SQLITE_INSERT 18 /* Table Name NULL */ 2156#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2157#define SQLITE_READ 20 /* Table Name Column Name */ 2158#define SQLITE_SELECT 21 /* NULL NULL */ 2159#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2160#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2161#define SQLITE_ATTACH 24 /* Filename NULL */ 2162#define SQLITE_DETACH 25 /* Database Name NULL */ 2163#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2164#define SQLITE_REINDEX 27 /* Index Name NULL */ 2165#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2166#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2167#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2168#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2169#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2170#define SQLITE_COPY 0 /* No longer used */ 2171 2172/* 2173** CAPI3REF: Tracing And Profiling Functions 2174** 2175** These routines register callback functions that can be used for 2176** tracing and profiling the execution of SQL statements. 2177** 2178** ^The callback function registered by sqlite3_trace() is invoked at 2179** various times when an SQL statement is being run by [sqlite3_step()]. 2180** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2181** SQL statement text as the statement first begins executing. 2182** ^(Additional sqlite3_trace() callbacks might occur 2183** as each triggered subprogram is entered. The callbacks for triggers 2184** contain a UTF-8 SQL comment that identifies the trigger.)^ 2185** 2186** ^The callback function registered by sqlite3_profile() is invoked 2187** as each SQL statement finishes. ^The profile callback contains 2188** the original statement text and an estimate of wall-clock time 2189** of how long that statement took to run. ^The profile callback 2190** time is in units of nanoseconds, however the current implementation 2191** is only capable of millisecond resolution so the six least significant 2192** digits in the time are meaningless. Future versions of SQLite 2193** might provide greater resolution on the profiler callback. The 2194** sqlite3_profile() function is considered experimental and is 2195** subject to change in future versions of SQLite. 2196*/ 2197void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2198SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2199 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2200 2201/* 2202** CAPI3REF: Query Progress Callbacks 2203** 2204** ^This routine configures a callback function - the 2205** progress callback - that is invoked periodically during long 2206** running calls to [sqlite3_exec()], [sqlite3_step()] and 2207** [sqlite3_get_table()]. An example use for this 2208** interface is to keep a GUI updated during a large query. 2209** 2210** ^If the progress callback returns non-zero, the operation is 2211** interrupted. This feature can be used to implement a 2212** "Cancel" button on a GUI progress dialog box. 2213** 2214** The progress handler must not do anything that will modify 2215** the database connection that invoked the progress handler. 2216** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2217** database connections for the meaning of "modify" in this paragraph. 2218** 2219*/ 2220void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2221 2222/* 2223** CAPI3REF: Opening A New Database Connection 2224** 2225** ^These routines open an SQLite database file whose name is given by the 2226** filename argument. ^The filename argument is interpreted as UTF-8 for 2227** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2228** order for sqlite3_open16(). ^(A [database connection] handle is usually 2229** returned in *ppDb, even if an error occurs. The only exception is that 2230** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2231** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2232** object.)^ ^(If the database is opened (and/or created) successfully, then 2233** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2234** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2235** an English language description of the error following a failure of any 2236** of the sqlite3_open() routines. 2237** 2238** ^The default encoding for the database will be UTF-8 if 2239** sqlite3_open() or sqlite3_open_v2() is called and 2240** UTF-16 in the native byte order if sqlite3_open16() is used. 2241** 2242** Whether or not an error occurs when it is opened, resources 2243** associated with the [database connection] handle should be released by 2244** passing it to [sqlite3_close()] when it is no longer required. 2245** 2246** The sqlite3_open_v2() interface works like sqlite3_open() 2247** except that it accepts two additional parameters for additional control 2248** over the new database connection. ^(The flags parameter to 2249** sqlite3_open_v2() can take one of 2250** the following three values, optionally combined with the 2251** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2252** and/or [SQLITE_OPEN_PRIVATECACHE] flags:)^ 2253** 2254** <dl> 2255** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2256** <dd>The database is opened in read-only mode. If the database does not 2257** already exist, an error is returned.</dd>)^ 2258** 2259** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2260** <dd>The database is opened for reading and writing if possible, or reading 2261** only if the file is write protected by the operating system. In either 2262** case the database must already exist, otherwise an error is returned.</dd>)^ 2263** 2264** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2265** <dd>The database is opened for reading and writing, and is creates it if 2266** it does not already exist. This is the behavior that is always used for 2267** sqlite3_open() and sqlite3_open16().</dd>)^ 2268** </dl> 2269** 2270** If the 3rd parameter to sqlite3_open_v2() is not one of the 2271** combinations shown above or one of the combinations shown above combined 2272** with the [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], 2273** [SQLITE_OPEN_SHAREDCACHE] and/or [SQLITE_OPEN_PRIVATECACHE] flags, 2274** then the behavior is undefined. 2275** 2276** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2277** opens in the multi-thread [threading mode] as long as the single-thread 2278** mode has not been set at compile-time or start-time. ^If the 2279** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2280** in the serialized [threading mode] unless single-thread was 2281** previously selected at compile-time or start-time. 2282** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2283** eligible to use [shared cache mode], regardless of whether or not shared 2284** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2285** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2286** participate in [shared cache mode] even if it is enabled. 2287** 2288** ^If the filename is ":memory:", then a private, temporary in-memory database 2289** is created for the connection. ^This in-memory database will vanish when 2290** the database connection is closed. Future versions of SQLite might 2291** make use of additional special filenames that begin with the ":" character. 2292** It is recommended that when a database filename actually does begin with 2293** a ":" character you should prefix the filename with a pathname such as 2294** "./" to avoid ambiguity. 2295** 2296** ^If the filename is an empty string, then a private, temporary 2297** on-disk database will be created. ^This private database will be 2298** automatically deleted as soon as the database connection is closed. 2299** 2300** ^The fourth parameter to sqlite3_open_v2() is the name of the 2301** [sqlite3_vfs] object that defines the operating system interface that 2302** the new database connection should use. ^If the fourth parameter is 2303** a NULL pointer then the default [sqlite3_vfs] object is used. 2304** 2305** <b>Note to Windows users:</b> The encoding used for the filename argument 2306** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2307** codepage is currently defined. Filenames containing international 2308** characters must be converted to UTF-8 prior to passing them into 2309** sqlite3_open() or sqlite3_open_v2(). 2310*/ 2311int sqlite3_open( 2312 const char *filename, /* Database filename (UTF-8) */ 2313 sqlite3 **ppDb /* OUT: SQLite db handle */ 2314); 2315int sqlite3_open16( 2316 const void *filename, /* Database filename (UTF-16) */ 2317 sqlite3 **ppDb /* OUT: SQLite db handle */ 2318); 2319int sqlite3_open_v2( 2320 const char *filename, /* Database filename (UTF-8) */ 2321 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2322 int flags, /* Flags */ 2323 const char *zVfs /* Name of VFS module to use */ 2324); 2325 2326/* 2327** CAPI3REF: Error Codes And Messages 2328** 2329** ^The sqlite3_errcode() interface returns the numeric [result code] or 2330** [extended result code] for the most recent failed sqlite3_* API call 2331** associated with a [database connection]. If a prior API call failed 2332** but the most recent API call succeeded, the return value from 2333** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2334** interface is the same except that it always returns the 2335** [extended result code] even when extended result codes are 2336** disabled. 2337** 2338** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2339** text that describes the error, as either UTF-8 or UTF-16 respectively. 2340** ^(Memory to hold the error message string is managed internally. 2341** The application does not need to worry about freeing the result. 2342** However, the error string might be overwritten or deallocated by 2343** subsequent calls to other SQLite interface functions.)^ 2344** 2345** When the serialized [threading mode] is in use, it might be the 2346** case that a second error occurs on a separate thread in between 2347** the time of the first error and the call to these interfaces. 2348** When that happens, the second error will be reported since these 2349** interfaces always report the most recent result. To avoid 2350** this, each thread can obtain exclusive use of the [database connection] D 2351** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2352** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2353** all calls to the interfaces listed here are completed. 2354** 2355** If an interface fails with SQLITE_MISUSE, that means the interface 2356** was invoked incorrectly by the application. In that case, the 2357** error code and message may or may not be set. 2358*/ 2359int sqlite3_errcode(sqlite3 *db); 2360int sqlite3_extended_errcode(sqlite3 *db); 2361const char *sqlite3_errmsg(sqlite3*); 2362const void *sqlite3_errmsg16(sqlite3*); 2363 2364/* 2365** CAPI3REF: SQL Statement Object 2366** KEYWORDS: {prepared statement} {prepared statements} 2367** 2368** An instance of this object represents a single SQL statement. 2369** This object is variously known as a "prepared statement" or a 2370** "compiled SQL statement" or simply as a "statement". 2371** 2372** The life of a statement object goes something like this: 2373** 2374** <ol> 2375** <li> Create the object using [sqlite3_prepare_v2()] or a related 2376** function. 2377** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2378** interfaces. 2379** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2380** <li> Reset the statement using [sqlite3_reset()] then go back 2381** to step 2. Do this zero or more times. 2382** <li> Destroy the object using [sqlite3_finalize()]. 2383** </ol> 2384** 2385** Refer to documentation on individual methods above for additional 2386** information. 2387*/ 2388typedef struct sqlite3_stmt sqlite3_stmt; 2389 2390/* 2391** CAPI3REF: Run-time Limits 2392** 2393** ^(This interface allows the size of various constructs to be limited 2394** on a connection by connection basis. The first parameter is the 2395** [database connection] whose limit is to be set or queried. The 2396** second parameter is one of the [limit categories] that define a 2397** class of constructs to be size limited. The third parameter is the 2398** new limit for that construct. The function returns the old limit.)^ 2399** 2400** ^If the new limit is a negative number, the limit is unchanged. 2401** ^(For the limit category of SQLITE_LIMIT_XYZ there is a 2402** [limits | hard upper bound] 2403** set by a compile-time C preprocessor macro named 2404** [limits | SQLITE_MAX_XYZ]. 2405** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2406** ^Attempts to increase a limit above its hard upper bound are 2407** silently truncated to the hard upper bound. 2408** 2409** Run-time limits are intended for use in applications that manage 2410** both their own internal database and also databases that are controlled 2411** by untrusted external sources. An example application might be a 2412** web browser that has its own databases for storing history and 2413** separate databases controlled by JavaScript applications downloaded 2414** off the Internet. The internal databases can be given the 2415** large, default limits. Databases managed by external sources can 2416** be given much smaller limits designed to prevent a denial of service 2417** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2418** interface to further control untrusted SQL. The size of the database 2419** created by an untrusted script can be contained using the 2420** [max_page_count] [PRAGMA]. 2421** 2422** New run-time limit categories may be added in future releases. 2423*/ 2424int sqlite3_limit(sqlite3*, int id, int newVal); 2425 2426/* 2427** CAPI3REF: Run-Time Limit Categories 2428** KEYWORDS: {limit category} {*limit categories} 2429** 2430** These constants define various performance limits 2431** that can be lowered at run-time using [sqlite3_limit()]. 2432** The synopsis of the meanings of the various limits is shown below. 2433** Additional information is available at [limits | Limits in SQLite]. 2434** 2435** <dl> 2436** ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2437** <dd>The maximum size of any string or BLOB or table row.<dd>)^ 2438** 2439** ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2440** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2441** 2442** ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2443** <dd>The maximum number of columns in a table definition or in the 2444** result set of a [SELECT] or the maximum number of columns in an index 2445** or in an ORDER BY or GROUP BY clause.</dd>)^ 2446** 2447** ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2448** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2449** 2450** ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2451** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2452** 2453** ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2454** <dd>The maximum number of instructions in a virtual machine program 2455** used to implement an SQL statement.</dd>)^ 2456** 2457** ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2458** <dd>The maximum number of arguments on a function.</dd>)^ 2459** 2460** ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2461** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2462** 2463** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2464** <dd>The maximum length of the pattern argument to the [LIKE] or 2465** [GLOB] operators.</dd>)^ 2466** 2467** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2468** <dd>The maximum number of variables in an SQL statement that can 2469** be bound.</dd>)^ 2470** 2471** ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2472** <dd>The maximum depth of recursion for triggers.</dd>)^ 2473** </dl> 2474*/ 2475#define SQLITE_LIMIT_LENGTH 0 2476#define SQLITE_LIMIT_SQL_LENGTH 1 2477#define SQLITE_LIMIT_COLUMN 2 2478#define SQLITE_LIMIT_EXPR_DEPTH 3 2479#define SQLITE_LIMIT_COMPOUND_SELECT 4 2480#define SQLITE_LIMIT_VDBE_OP 5 2481#define SQLITE_LIMIT_FUNCTION_ARG 6 2482#define SQLITE_LIMIT_ATTACHED 7 2483#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2484#define SQLITE_LIMIT_VARIABLE_NUMBER 9 2485#define SQLITE_LIMIT_TRIGGER_DEPTH 10 2486 2487/* 2488** CAPI3REF: Compiling An SQL Statement 2489** KEYWORDS: {SQL statement compiler} 2490** 2491** To execute an SQL query, it must first be compiled into a byte-code 2492** program using one of these routines. 2493** 2494** The first argument, "db", is a [database connection] obtained from a 2495** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2496** [sqlite3_open16()]. The database connection must not have been closed. 2497** 2498** The second argument, "zSql", is the statement to be compiled, encoded 2499** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2500** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2501** use UTF-16. 2502** 2503** ^If the nByte argument is less than zero, then zSql is read up to the 2504** first zero terminator. ^If nByte is non-negative, then it is the maximum 2505** number of bytes read from zSql. ^When nByte is non-negative, the 2506** zSql string ends at either the first '\000' or '\u0000' character or 2507** the nByte-th byte, whichever comes first. If the caller knows 2508** that the supplied string is nul-terminated, then there is a small 2509** performance advantage to be gained by passing an nByte parameter that 2510** is equal to the number of bytes in the input string <i>including</i> 2511** the nul-terminator bytes. 2512** 2513** ^If pzTail is not NULL then *pzTail is made to point to the first byte 2514** past the end of the first SQL statement in zSql. These routines only 2515** compile the first statement in zSql, so *pzTail is left pointing to 2516** what remains uncompiled. 2517** 2518** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 2519** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 2520** to NULL. ^If the input text contains no SQL (if the input is an empty 2521** string or a comment) then *ppStmt is set to NULL. 2522** The calling procedure is responsible for deleting the compiled 2523** SQL statement using [sqlite3_finalize()] after it has finished with it. 2524** ppStmt may not be NULL. 2525** 2526** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 2527** otherwise an [error code] is returned. 2528** 2529** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2530** recommended for all new programs. The two older interfaces are retained 2531** for backwards compatibility, but their use is discouraged. 2532** ^In the "v2" interfaces, the prepared statement 2533** that is returned (the [sqlite3_stmt] object) contains a copy of the 2534** original SQL text. This causes the [sqlite3_step()] interface to 2535** behave differently in three ways: 2536** 2537** <ol> 2538** <li> 2539** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2540** always used to do, [sqlite3_step()] will automatically recompile the SQL 2541** statement and try to run it again. ^If the schema has changed in 2542** a way that makes the statement no longer valid, [sqlite3_step()] will still 2543** return [SQLITE_SCHEMA]. But unlike the legacy behavior, [SQLITE_SCHEMA] is 2544** now a fatal error. Calling [sqlite3_prepare_v2()] again will not make the 2545** error go away. Note: use [sqlite3_errmsg()] to find the text 2546** of the parsing error that results in an [SQLITE_SCHEMA] return. 2547** </li> 2548** 2549** <li> 2550** ^When an error occurs, [sqlite3_step()] will return one of the detailed 2551** [error codes] or [extended error codes]. ^The legacy behavior was that 2552** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2553** and the application would have to make a second call to [sqlite3_reset()] 2554** in order to find the underlying cause of the problem. With the "v2" prepare 2555** interfaces, the underlying reason for the error is returned immediately. 2556** </li> 2557** 2558** <li> 2559** ^If the value of a [parameter | host parameter] in the WHERE clause might 2560** change the query plan for a statement, then the statement may be 2561** automatically recompiled (as if there had been a schema change) on the first 2562** [sqlite3_step()] call following any change to the 2563** [sqlite3_bind_text | bindings] of the [parameter]. 2564** </li> 2565** </ol> 2566*/ 2567int sqlite3_prepare( 2568 sqlite3 *db, /* Database handle */ 2569 const char *zSql, /* SQL statement, UTF-8 encoded */ 2570 int nByte, /* Maximum length of zSql in bytes. */ 2571 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2572 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2573); 2574int sqlite3_prepare_v2( 2575 sqlite3 *db, /* Database handle */ 2576 const char *zSql, /* SQL statement, UTF-8 encoded */ 2577 int nByte, /* Maximum length of zSql in bytes. */ 2578 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2579 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2580); 2581int sqlite3_prepare16( 2582 sqlite3 *db, /* Database handle */ 2583 const void *zSql, /* SQL statement, UTF-16 encoded */ 2584 int nByte, /* Maximum length of zSql in bytes. */ 2585 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2586 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2587); 2588int sqlite3_prepare16_v2( 2589 sqlite3 *db, /* Database handle */ 2590 const void *zSql, /* SQL statement, UTF-16 encoded */ 2591 int nByte, /* Maximum length of zSql in bytes. */ 2592 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2593 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2594); 2595 2596/* 2597** CAPI3REF: Retrieving Statement SQL 2598** 2599** ^This interface can be used to retrieve a saved copy of the original 2600** SQL text used to create a [prepared statement] if that statement was 2601** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2602*/ 2603const char *sqlite3_sql(sqlite3_stmt *pStmt); 2604 2605/* 2606** CAPI3REF: Dynamically Typed Value Object 2607** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 2608** 2609** SQLite uses the sqlite3_value object to represent all values 2610** that can be stored in a database table. SQLite uses dynamic typing 2611** for the values it stores. ^Values stored in sqlite3_value objects 2612** can be integers, floating point values, strings, BLOBs, or NULL. 2613** 2614** An sqlite3_value object may be either "protected" or "unprotected". 2615** Some interfaces require a protected sqlite3_value. Other interfaces 2616** will accept either a protected or an unprotected sqlite3_value. 2617** Every interface that accepts sqlite3_value arguments specifies 2618** whether or not it requires a protected sqlite3_value. 2619** 2620** The terms "protected" and "unprotected" refer to whether or not 2621** a mutex is held. A internal mutex is held for a protected 2622** sqlite3_value object but no mutex is held for an unprotected 2623** sqlite3_value object. If SQLite is compiled to be single-threaded 2624** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 2625** or if SQLite is run in one of reduced mutex modes 2626** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 2627** then there is no distinction between protected and unprotected 2628** sqlite3_value objects and they can be used interchangeably. However, 2629** for maximum code portability it is recommended that applications 2630** still make the distinction between protected and unprotected 2631** sqlite3_value objects even when not strictly required. 2632** 2633** ^The sqlite3_value objects that are passed as parameters into the 2634** implementation of [application-defined SQL functions] are protected. 2635** ^The sqlite3_value object returned by 2636** [sqlite3_column_value()] is unprotected. 2637** Unprotected sqlite3_value objects may only be used with 2638** [sqlite3_result_value()] and [sqlite3_bind_value()]. 2639** The [sqlite3_value_blob | sqlite3_value_type()] family of 2640** interfaces require protected sqlite3_value objects. 2641*/ 2642typedef struct Mem sqlite3_value; 2643 2644/* 2645** CAPI3REF: SQL Function Context Object 2646** 2647** The context in which an SQL function executes is stored in an 2648** sqlite3_context object. ^A pointer to an sqlite3_context object 2649** is always first parameter to [application-defined SQL functions]. 2650** The application-defined SQL function implementation will pass this 2651** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 2652** [sqlite3_aggregate_context()], [sqlite3_user_data()], 2653** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 2654** and/or [sqlite3_set_auxdata()]. 2655*/ 2656typedef struct sqlite3_context sqlite3_context; 2657 2658/* 2659** CAPI3REF: Binding Values To Prepared Statements 2660** KEYWORDS: {host parameter} {host parameters} {host parameter name} 2661** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 2662** 2663** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 2664** literals may be replaced by a [parameter] that matches one of following 2665** templates: 2666** 2667** <ul> 2668** <li> ? 2669** <li> ?NNN 2670** <li> :VVV 2671** <li> @VVV 2672** <li> $VVV 2673** </ul> 2674** 2675** In the templates above, NNN represents an integer literal, 2676** and VVV represents an alphanumeric identifier.)^ ^The values of these 2677** parameters (also called "host parameter names" or "SQL parameters") 2678** can be set using the sqlite3_bind_*() routines defined here. 2679** 2680** ^The first argument to the sqlite3_bind_*() routines is always 2681** a pointer to the [sqlite3_stmt] object returned from 2682** [sqlite3_prepare_v2()] or its variants. 2683** 2684** ^The second argument is the index of the SQL parameter to be set. 2685** ^The leftmost SQL parameter has an index of 1. ^When the same named 2686** SQL parameter is used more than once, second and subsequent 2687** occurrences have the same index as the first occurrence. 2688** ^The index for named parameters can be looked up using the 2689** [sqlite3_bind_parameter_index()] API if desired. ^The index 2690** for "?NNN" parameters is the value of NNN. 2691** ^The NNN value must be between 1 and the [sqlite3_limit()] 2692** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 2693** 2694** ^The third argument is the value to bind to the parameter. 2695** 2696** ^(In those routines that have a fourth argument, its value is the 2697** number of bytes in the parameter. To be clear: the value is the 2698** number of <u>bytes</u> in the value, not the number of characters.)^ 2699** ^If the fourth parameter is negative, the length of the string is 2700** the number of bytes up to the first zero terminator. 2701** 2702** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 2703** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 2704** string after SQLite has finished with it. ^If the fifth argument is 2705** the special value [SQLITE_STATIC], then SQLite assumes that the 2706** information is in static, unmanaged space and does not need to be freed. 2707** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 2708** SQLite makes its own private copy of the data immediately, before 2709** the sqlite3_bind_*() routine returns. 2710** 2711** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 2712** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 2713** (just an integer to hold its size) while it is being processed. 2714** Zeroblobs are intended to serve as placeholders for BLOBs whose 2715** content is later written using 2716** [sqlite3_blob_open | incremental BLOB I/O] routines. 2717** ^A negative value for the zeroblob results in a zero-length BLOB. 2718** 2719** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 2720** for the [prepared statement] or with a prepared statement for which 2721** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 2722** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 2723** routine is passed a [prepared statement] that has been finalized, the 2724** result is undefined and probably harmful. 2725** 2726** ^Bindings are not cleared by the [sqlite3_reset()] routine. 2727** ^Unbound parameters are interpreted as NULL. 2728** 2729** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 2730** [error code] if anything goes wrong. 2731** ^[SQLITE_RANGE] is returned if the parameter 2732** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 2733** 2734** See also: [sqlite3_bind_parameter_count()], 2735** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 2736*/ 2737int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 2738int sqlite3_bind_double(sqlite3_stmt*, int, double); 2739int sqlite3_bind_int(sqlite3_stmt*, int, int); 2740int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 2741int sqlite3_bind_null(sqlite3_stmt*, int); 2742int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 2743int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 2744int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 2745int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 2746 2747/* 2748** CAPI3REF: Number Of SQL Parameters 2749** 2750** ^This routine can be used to find the number of [SQL parameters] 2751** in a [prepared statement]. SQL parameters are tokens of the 2752** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 2753** placeholders for values that are [sqlite3_bind_blob | bound] 2754** to the parameters at a later time. 2755** 2756** ^(This routine actually returns the index of the largest (rightmost) 2757** parameter. For all forms except ?NNN, this will correspond to the 2758** number of unique parameters. If parameters of the ?NNN form are used, 2759** there may be gaps in the list.)^ 2760** 2761** See also: [sqlite3_bind_blob|sqlite3_bind()], 2762** [sqlite3_bind_parameter_name()], and 2763** [sqlite3_bind_parameter_index()]. 2764*/ 2765int sqlite3_bind_parameter_count(sqlite3_stmt*); 2766 2767/* 2768** CAPI3REF: Name Of A Host Parameter 2769** 2770** ^The sqlite3_bind_parameter_name(P,N) interface returns 2771** the name of the N-th [SQL parameter] in the [prepared statement] P. 2772** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 2773** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 2774** respectively. 2775** In other words, the initial ":" or "$" or "@" or "?" 2776** is included as part of the name.)^ 2777** ^Parameters of the form "?" without a following integer have no name 2778** and are referred to as "nameless" or "anonymous parameters". 2779** 2780** ^The first host parameter has an index of 1, not 0. 2781** 2782** ^If the value N is out of range or if the N-th parameter is 2783** nameless, then NULL is returned. ^The returned string is 2784** always in UTF-8 encoding even if the named parameter was 2785** originally specified as UTF-16 in [sqlite3_prepare16()] or 2786** [sqlite3_prepare16_v2()]. 2787** 2788** See also: [sqlite3_bind_blob|sqlite3_bind()], 2789** [sqlite3_bind_parameter_count()], and 2790** [sqlite3_bind_parameter_index()]. 2791*/ 2792const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 2793 2794/* 2795** CAPI3REF: Index Of A Parameter With A Given Name 2796** 2797** ^Return the index of an SQL parameter given its name. ^The 2798** index value returned is suitable for use as the second 2799** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 2800** is returned if no matching parameter is found. ^The parameter 2801** name must be given in UTF-8 even if the original statement 2802** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 2803** 2804** See also: [sqlite3_bind_blob|sqlite3_bind()], 2805** [sqlite3_bind_parameter_count()], and 2806** [sqlite3_bind_parameter_index()]. 2807*/ 2808int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 2809 2810/* 2811** CAPI3REF: Reset All Bindings On A Prepared Statement 2812** 2813** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 2814** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 2815** ^Use this routine to reset all host parameters to NULL. 2816*/ 2817int sqlite3_clear_bindings(sqlite3_stmt*); 2818 2819/* 2820** CAPI3REF: Number Of Columns In A Result Set 2821** 2822** ^Return the number of columns in the result set returned by the 2823** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 2824** statement that does not return data (for example an [UPDATE]). 2825** 2826** See also: [sqlite3_data_count()] 2827*/ 2828int sqlite3_column_count(sqlite3_stmt *pStmt); 2829 2830/* 2831** CAPI3REF: Column Names In A Result Set 2832** 2833** ^These routines return the name assigned to a particular column 2834** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 2835** interface returns a pointer to a zero-terminated UTF-8 string 2836** and sqlite3_column_name16() returns a pointer to a zero-terminated 2837** UTF-16 string. ^The first parameter is the [prepared statement] 2838** that implements the [SELECT] statement. ^The second parameter is the 2839** column number. ^The leftmost column is number 0. 2840** 2841** ^The returned string pointer is valid until either the [prepared statement] 2842** is destroyed by [sqlite3_finalize()] or until the next call to 2843** sqlite3_column_name() or sqlite3_column_name16() on the same column. 2844** 2845** ^If sqlite3_malloc() fails during the processing of either routine 2846** (for example during a conversion from UTF-8 to UTF-16) then a 2847** NULL pointer is returned. 2848** 2849** ^The name of a result column is the value of the "AS" clause for 2850** that column, if there is an AS clause. If there is no AS clause 2851** then the name of the column is unspecified and may change from 2852** one release of SQLite to the next. 2853*/ 2854const char *sqlite3_column_name(sqlite3_stmt*, int N); 2855const void *sqlite3_column_name16(sqlite3_stmt*, int N); 2856 2857/* 2858** CAPI3REF: Source Of Data In A Query Result 2859** 2860** ^These routines provide a means to determine the database, table, and 2861** table column that is the origin of a particular result column in 2862** [SELECT] statement. 2863** ^The name of the database or table or column can be returned as 2864** either a UTF-8 or UTF-16 string. ^The _database_ routines return 2865** the database name, the _table_ routines return the table name, and 2866** the origin_ routines return the column name. 2867** ^The returned string is valid until the [prepared statement] is destroyed 2868** using [sqlite3_finalize()] or until the same information is requested 2869** again in a different encoding. 2870** 2871** ^The names returned are the original un-aliased names of the 2872** database, table, and column. 2873** 2874** ^The first argument to these interfaces is a [prepared statement]. 2875** ^These functions return information about the Nth result column returned by 2876** the statement, where N is the second function argument. 2877** ^The left-most column is column 0 for these routines. 2878** 2879** ^If the Nth column returned by the statement is an expression or 2880** subquery and is not a column value, then all of these functions return 2881** NULL. ^These routine might also return NULL if a memory allocation error 2882** occurs. ^Otherwise, they return the name of the attached database, table, 2883** or column that query result column was extracted from. 2884** 2885** ^As with all other SQLite APIs, those whose names end with "16" return 2886** UTF-16 encoded strings and the other functions return UTF-8. 2887** 2888** ^These APIs are only available if the library was compiled with the 2889** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 2890** 2891** If two or more threads call one or more of these routines against the same 2892** prepared statement and column at the same time then the results are 2893** undefined. 2894** 2895** If two or more threads call one or more 2896** [sqlite3_column_database_name | column metadata interfaces] 2897** for the same [prepared statement] and result column 2898** at the same time then the results are undefined. 2899*/ 2900const char *sqlite3_column_database_name(sqlite3_stmt*,int); 2901const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 2902const char *sqlite3_column_table_name(sqlite3_stmt*,int); 2903const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 2904const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 2905const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 2906 2907/* 2908** CAPI3REF: Declared Datatype Of A Query Result 2909** 2910** ^(The first parameter is a [prepared statement]. 2911** If this statement is a [SELECT] statement and the Nth column of the 2912** returned result set of that [SELECT] is a table column (not an 2913** expression or subquery) then the declared type of the table 2914** column is returned.)^ ^If the Nth column of the result set is an 2915** expression or subquery, then a NULL pointer is returned. 2916** ^The returned string is always UTF-8 encoded. 2917** 2918** ^(For example, given the database schema: 2919** 2920** CREATE TABLE t1(c1 VARIANT); 2921** 2922** and the following statement to be compiled: 2923** 2924** SELECT c1 + 1, c1 FROM t1; 2925** 2926** this routine would return the string "VARIANT" for the second result 2927** column (i==1), and a NULL pointer for the first result column (i==0).)^ 2928** 2929** ^SQLite uses dynamic run-time typing. ^So just because a column 2930** is declared to contain a particular type does not mean that the 2931** data stored in that column is of the declared type. SQLite is 2932** strongly typed, but the typing is dynamic not static. ^Type 2933** is associated with individual values, not with the containers 2934** used to hold those values. 2935*/ 2936const char *sqlite3_column_decltype(sqlite3_stmt*,int); 2937const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 2938 2939/* 2940** CAPI3REF: Evaluate An SQL Statement 2941** 2942** After a [prepared statement] has been prepared using either 2943** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 2944** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 2945** must be called one or more times to evaluate the statement. 2946** 2947** The details of the behavior of the sqlite3_step() interface depend 2948** on whether the statement was prepared using the newer "v2" interface 2949** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 2950** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 2951** new "v2" interface is recommended for new applications but the legacy 2952** interface will continue to be supported. 2953** 2954** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 2955** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 2956** ^With the "v2" interface, any of the other [result codes] or 2957** [extended result codes] might be returned as well. 2958** 2959** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 2960** database locks it needs to do its job. ^If the statement is a [COMMIT] 2961** or occurs outside of an explicit transaction, then you can retry the 2962** statement. If the statement is not a [COMMIT] and occurs within a 2963** explicit transaction then you should rollback the transaction before 2964** continuing. 2965** 2966** ^[SQLITE_DONE] means that the statement has finished executing 2967** successfully. sqlite3_step() should not be called again on this virtual 2968** machine without first calling [sqlite3_reset()] to reset the virtual 2969** machine back to its initial state. 2970** 2971** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 2972** is returned each time a new row of data is ready for processing by the 2973** caller. The values may be accessed using the [column access functions]. 2974** sqlite3_step() is called again to retrieve the next row of data. 2975** 2976** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 2977** violation) has occurred. sqlite3_step() should not be called again on 2978** the VM. More information may be found by calling [sqlite3_errmsg()]. 2979** ^With the legacy interface, a more specific error code (for example, 2980** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 2981** can be obtained by calling [sqlite3_reset()] on the 2982** [prepared statement]. ^In the "v2" interface, 2983** the more specific error code is returned directly by sqlite3_step(). 2984** 2985** [SQLITE_MISUSE] means that the this routine was called inappropriately. 2986** Perhaps it was called on a [prepared statement] that has 2987** already been [sqlite3_finalize | finalized] or on one that had 2988** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 2989** be the case that the same database connection is being used by two or 2990** more threads at the same moment in time. 2991** 2992** For all versions of SQLite up to and including 3.6.23.1, it was required 2993** after sqlite3_step() returned anything other than [SQLITE_ROW] that 2994** [sqlite3_reset()] be called before any subsequent invocation of 2995** sqlite3_step(). Failure to invoke [sqlite3_reset()] in this way would 2996** result in an [SQLITE_MISUSE] return from sqlite3_step(). But after 2997** version 3.6.23.1, sqlite3_step() began calling [sqlite3_reset()] 2998** automatically in this circumstance rather than returning [SQLITE_MISUSE]. 2999** 3000** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3001** API always returns a generic error code, [SQLITE_ERROR], following any 3002** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3003** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3004** specific [error codes] that better describes the error. 3005** We admit that this is a goofy design. The problem has been fixed 3006** with the "v2" interface. If you prepare all of your SQL statements 3007** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3008** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3009** then the more specific [error codes] are returned directly 3010** by sqlite3_step(). The use of the "v2" interface is recommended. 3011*/ 3012int sqlite3_step(sqlite3_stmt*); 3013 3014/* 3015** CAPI3REF: Number of columns in a result set 3016** 3017** ^The sqlite3_data_count(P) interface returns the number of columns in the 3018** current row of the result set of [prepared statement] P. 3019** ^If prepared statement P does not have results ready to return 3020** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3021** interfaces) then sqlite3_data_count(P) returns 0. 3022** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3023** 3024** See also: [sqlite3_column_count()] 3025*/ 3026int sqlite3_data_count(sqlite3_stmt *pStmt); 3027 3028/* 3029** CAPI3REF: Fundamental Datatypes 3030** KEYWORDS: SQLITE_TEXT 3031** 3032** ^(Every value in SQLite has one of five fundamental datatypes: 3033** 3034** <ul> 3035** <li> 64-bit signed integer 3036** <li> 64-bit IEEE floating point number 3037** <li> string 3038** <li> BLOB 3039** <li> NULL 3040** </ul>)^ 3041** 3042** These constants are codes for each of those types. 3043** 3044** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3045** for a completely different meaning. Software that links against both 3046** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3047** SQLITE_TEXT. 3048*/ 3049#define SQLITE_INTEGER 1 3050#define SQLITE_FLOAT 2 3051#define SQLITE_BLOB 4 3052#define SQLITE_NULL 5 3053#ifdef SQLITE_TEXT 3054# undef SQLITE_TEXT 3055#else 3056# define SQLITE_TEXT 3 3057#endif 3058#define SQLITE3_TEXT 3 3059 3060/* 3061** CAPI3REF: Result Values From A Query 3062** KEYWORDS: {column access functions} 3063** 3064** These routines form the "result set" interface. 3065** 3066** ^These routines return information about a single column of the current 3067** result row of a query. ^In every case the first argument is a pointer 3068** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3069** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3070** and the second argument is the index of the column for which information 3071** should be returned. ^The leftmost column of the result set has the index 0. 3072** ^The number of columns in the result can be determined using 3073** [sqlite3_column_count()]. 3074** 3075** If the SQL statement does not currently point to a valid row, or if the 3076** column index is out of range, the result is undefined. 3077** These routines may only be called when the most recent call to 3078** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3079** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3080** If any of these routines are called after [sqlite3_reset()] or 3081** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3082** something other than [SQLITE_ROW], the results are undefined. 3083** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3084** are called from a different thread while any of these routines 3085** are pending, then the results are undefined. 3086** 3087** ^The sqlite3_column_type() routine returns the 3088** [SQLITE_INTEGER | datatype code] for the initial data type 3089** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3090** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3091** returned by sqlite3_column_type() is only meaningful if no type 3092** conversions have occurred as described below. After a type conversion, 3093** the value returned by sqlite3_column_type() is undefined. Future 3094** versions of SQLite may change the behavior of sqlite3_column_type() 3095** following a type conversion. 3096** 3097** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3098** routine returns the number of bytes in that BLOB or string. 3099** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3100** the string to UTF-8 and then returns the number of bytes. 3101** ^If the result is a numeric value then sqlite3_column_bytes() uses 3102** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3103** the number of bytes in that string. 3104** ^The value returned does not include the zero terminator at the end 3105** of the string. ^For clarity: the value returned is the number of 3106** bytes in the string, not the number of characters. 3107** 3108** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3109** even empty strings, are always zero terminated. ^The return 3110** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary 3111** pointer, possibly even a NULL pointer. 3112** 3113** ^The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes() 3114** but leaves the result in UTF-16 in native byte order instead of UTF-8. 3115** ^The zero terminator is not included in this count. 3116** 3117** ^The object returned by [sqlite3_column_value()] is an 3118** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3119** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3120** If the [unprotected sqlite3_value] object returned by 3121** [sqlite3_column_value()] is used in any other way, including calls 3122** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3123** or [sqlite3_value_bytes()], then the behavior is undefined. 3124** 3125** These routines attempt to convert the value where appropriate. ^For 3126** example, if the internal representation is FLOAT and a text result 3127** is requested, [sqlite3_snprintf()] is used internally to perform the 3128** conversion automatically. ^(The following table details the conversions 3129** that are applied: 3130** 3131** <blockquote> 3132** <table border="1"> 3133** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3134** 3135** <tr><td> NULL <td> INTEGER <td> Result is 0 3136** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3137** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3138** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3139** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3140** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3141** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3142** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3143** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3144** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3145** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3146** <tr><td> TEXT <td> FLOAT <td> Use atof() 3147** <tr><td> TEXT <td> BLOB <td> No change 3148** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3149** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3150** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3151** </table> 3152** </blockquote>)^ 3153** 3154** The table above makes reference to standard C library functions atoi() 3155** and atof(). SQLite does not really use these functions. It has its 3156** own equivalent internal routines. The atoi() and atof() names are 3157** used in the table for brevity and because they are familiar to most 3158** C programmers. 3159** 3160** ^Note that when type conversions occur, pointers returned by prior 3161** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3162** sqlite3_column_text16() may be invalidated. 3163** ^(Type conversions and pointer invalidations might occur 3164** in the following cases: 3165** 3166** <ul> 3167** <li> The initial content is a BLOB and sqlite3_column_text() or 3168** sqlite3_column_text16() is called. A zero-terminator might 3169** need to be added to the string.</li> 3170** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3171** sqlite3_column_text16() is called. The content must be converted 3172** to UTF-16.</li> 3173** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3174** sqlite3_column_text() is called. The content must be converted 3175** to UTF-8.</li> 3176** </ul>)^ 3177** 3178** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3179** not invalidate a prior pointer, though of course the content of the buffer 3180** that the prior pointer points to will have been modified. Other kinds 3181** of conversion are done in place when it is possible, but sometimes they 3182** are not possible and in those cases prior pointers are invalidated. 3183** 3184** ^(The safest and easiest to remember policy is to invoke these routines 3185** in one of the following ways: 3186** 3187** <ul> 3188** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3189** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3190** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3191** </ul>)^ 3192** 3193** In other words, you should call sqlite3_column_text(), 3194** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3195** into the desired format, then invoke sqlite3_column_bytes() or 3196** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3197** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3198** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3199** with calls to sqlite3_column_bytes(). 3200** 3201** ^The pointers returned are valid until a type conversion occurs as 3202** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3203** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3204** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3205** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3206** [sqlite3_free()]. 3207** 3208** ^(If a memory allocation error occurs during the evaluation of any 3209** of these routines, a default value is returned. The default value 3210** is either the integer 0, the floating point number 0.0, or a NULL 3211** pointer. Subsequent calls to [sqlite3_errcode()] will return 3212** [SQLITE_NOMEM].)^ 3213*/ 3214const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3215int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3216int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3217double sqlite3_column_double(sqlite3_stmt*, int iCol); 3218int sqlite3_column_int(sqlite3_stmt*, int iCol); 3219sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3220const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3221const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3222int sqlite3_column_type(sqlite3_stmt*, int iCol); 3223sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3224 3225/* 3226** CAPI3REF: Destroy A Prepared Statement Object 3227** 3228** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3229** ^If the statement was executed successfully or not executed at all, then 3230** SQLITE_OK is returned. ^If execution of the statement failed then an 3231** [error code] or [extended error code] is returned. 3232** 3233** ^This routine can be called at any point during the execution of the 3234** [prepared statement]. ^If the virtual machine has not 3235** completed execution when this routine is called, that is like 3236** encountering an error or an [sqlite3_interrupt | interrupt]. 3237** ^Incomplete updates may be rolled back and transactions canceled, 3238** depending on the circumstances, and the 3239** [error code] returned will be [SQLITE_ABORT]. 3240*/ 3241int sqlite3_finalize(sqlite3_stmt *pStmt); 3242 3243/* 3244** CAPI3REF: Reset A Prepared Statement Object 3245** 3246** The sqlite3_reset() function is called to reset a [prepared statement] 3247** object back to its initial state, ready to be re-executed. 3248** ^Any SQL statement variables that had values bound to them using 3249** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3250** Use [sqlite3_clear_bindings()] to reset the bindings. 3251** 3252** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3253** back to the beginning of its program. 3254** 3255** ^If the most recent call to [sqlite3_step(S)] for the 3256** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3257** or if [sqlite3_step(S)] has never before been called on S, 3258** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3259** 3260** ^If the most recent call to [sqlite3_step(S)] for the 3261** [prepared statement] S indicated an error, then 3262** [sqlite3_reset(S)] returns an appropriate [error code]. 3263** 3264** ^The [sqlite3_reset(S)] interface does not change the values 3265** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3266*/ 3267int sqlite3_reset(sqlite3_stmt *pStmt); 3268 3269/* 3270** CAPI3REF: Create Or Redefine SQL Functions 3271** KEYWORDS: {function creation routines} 3272** KEYWORDS: {application-defined SQL function} 3273** KEYWORDS: {application-defined SQL functions} 3274** 3275** ^These two functions (collectively known as "function creation routines") 3276** are used to add SQL functions or aggregates or to redefine the behavior 3277** of existing SQL functions or aggregates. The only difference between the 3278** two is that the second parameter, the name of the (scalar) function or 3279** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16 3280** for sqlite3_create_function16(). 3281** 3282** ^The first parameter is the [database connection] to which the SQL 3283** function is to be added. ^If an application uses more than one database 3284** connection then application-defined SQL functions must be added 3285** to each database connection separately. 3286** 3287** The second parameter is the name of the SQL function to be created or 3288** redefined. ^The length of the name is limited to 255 bytes, exclusive of 3289** the zero-terminator. Note that the name length limit is in bytes, not 3290** characters. ^Any attempt to create a function with a longer name 3291** will result in [SQLITE_ERROR] being returned. 3292** 3293** ^The third parameter (nArg) 3294** is the number of arguments that the SQL function or 3295** aggregate takes. ^If this parameter is -1, then the SQL function or 3296** aggregate may take any number of arguments between 0 and the limit 3297** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3298** parameter is less than -1 or greater than 127 then the behavior is 3299** undefined. 3300** 3301** The fourth parameter, eTextRep, specifies what 3302** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3303** its parameters. Any SQL function implementation should be able to work 3304** work with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3305** more efficient with one encoding than another. ^An application may 3306** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3307** times with the same function but with different values of eTextRep. 3308** ^When multiple implementations of the same function are available, SQLite 3309** will pick the one that involves the least amount of data conversion. 3310** If there is only a single implementation which does not care what text 3311** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3312** 3313** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3314** function can gain access to this pointer using [sqlite3_user_data()].)^ 3315** 3316** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are 3317** pointers to C-language functions that implement the SQL function or 3318** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3319** callback only; NULL pointers should be passed as the xStep and xFinal 3320** parameters. ^An aggregate SQL function requires an implementation of xStep 3321** and xFinal and NULL should be passed for xFunc. ^To delete an existing 3322** SQL function or aggregate, pass NULL for all three function callbacks. 3323** 3324** ^It is permitted to register multiple implementations of the same 3325** functions with the same name but with either differing numbers of 3326** arguments or differing preferred text encodings. ^SQLite will use 3327** the implementation that most closely matches the way in which the 3328** SQL function is used. ^A function implementation with a non-negative 3329** nArg parameter is a better match than a function implementation with 3330** a negative nArg. ^A function where the preferred text encoding 3331** matches the database encoding is a better 3332** match than a function where the encoding is different. 3333** ^A function where the encoding difference is between UTF16le and UTF16be 3334** is a closer match than a function where the encoding difference is 3335** between UTF8 and UTF16. 3336** 3337** ^Built-in functions may be overloaded by new application-defined functions. 3338** ^The first application-defined function with a given name overrides all 3339** built-in functions in the same [database connection] with the same name. 3340** ^Subsequent application-defined functions of the same name only override 3341** prior application-defined functions that are an exact match for the 3342** number of parameters and preferred encoding. 3343** 3344** ^An application-defined function is permitted to call other 3345** SQLite interfaces. However, such calls must not 3346** close the database connection nor finalize or reset the prepared 3347** statement in which the function is running. 3348*/ 3349int sqlite3_create_function( 3350 sqlite3 *db, 3351 const char *zFunctionName, 3352 int nArg, 3353 int eTextRep, 3354 void *pApp, 3355 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3356 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3357 void (*xFinal)(sqlite3_context*) 3358); 3359int sqlite3_create_function16( 3360 sqlite3 *db, 3361 const void *zFunctionName, 3362 int nArg, 3363 int eTextRep, 3364 void *pApp, 3365 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3366 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3367 void (*xFinal)(sqlite3_context*) 3368); 3369int sqlite3_create_function_v2( 3370 sqlite3 *db, 3371 const char *zFunctionName, 3372 int nArg, 3373 int eTextRep, 3374 void *pApp, 3375 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3376 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3377 void (*xFinal)(sqlite3_context*), 3378 void(*xDestroy)(void*) 3379); 3380 3381/* 3382** CAPI3REF: Text Encodings 3383** 3384** These constant define integer codes that represent the various 3385** text encodings supported by SQLite. 3386*/ 3387#define SQLITE_UTF8 1 3388#define SQLITE_UTF16LE 2 3389#define SQLITE_UTF16BE 3 3390#define SQLITE_UTF16 4 /* Use native byte order */ 3391#define SQLITE_ANY 5 /* sqlite3_create_function only */ 3392#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3393 3394/* 3395** CAPI3REF: Deprecated Functions 3396** DEPRECATED 3397** 3398** These functions are [deprecated]. In order to maintain 3399** backwards compatibility with older code, these functions continue 3400** to be supported. However, new applications should avoid 3401** the use of these functions. To help encourage people to avoid 3402** using these functions, we are not going to tell you what they do. 3403*/ 3404#ifndef SQLITE_OMIT_DEPRECATED 3405SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3406SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3407SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3408SQLITE_DEPRECATED int sqlite3_global_recover(void); 3409SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3410SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3411#endif 3412 3413/* 3414** CAPI3REF: Obtaining SQL Function Parameter Values 3415** 3416** The C-language implementation of SQL functions and aggregates uses 3417** this set of interface routines to access the parameter values on 3418** the function or aggregate. 3419** 3420** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3421** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3422** define callbacks that implement the SQL functions and aggregates. 3423** The 4th parameter to these callbacks is an array of pointers to 3424** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3425** each parameter to the SQL function. These routines are used to 3426** extract values from the [sqlite3_value] objects. 3427** 3428** These routines work only with [protected sqlite3_value] objects. 3429** Any attempt to use these routines on an [unprotected sqlite3_value] 3430** object results in undefined behavior. 3431** 3432** ^These routines work just like the corresponding [column access functions] 3433** except that these routines take a single [protected sqlite3_value] object 3434** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3435** 3436** ^The sqlite3_value_text16() interface extracts a UTF-16 string 3437** in the native byte-order of the host machine. ^The 3438** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3439** extract UTF-16 strings as big-endian and little-endian respectively. 3440** 3441** ^(The sqlite3_value_numeric_type() interface attempts to apply 3442** numeric affinity to the value. This means that an attempt is 3443** made to convert the value to an integer or floating point. If 3444** such a conversion is possible without loss of information (in other 3445** words, if the value is a string that looks like a number) 3446** then the conversion is performed. Otherwise no conversion occurs. 3447** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 3448** 3449** Please pay particular attention to the fact that the pointer returned 3450** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3451** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3452** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3453** or [sqlite3_value_text16()]. 3454** 3455** These routines must be called from the same thread as 3456** the SQL function that supplied the [sqlite3_value*] parameters. 3457*/ 3458const void *sqlite3_value_blob(sqlite3_value*); 3459int sqlite3_value_bytes(sqlite3_value*); 3460int sqlite3_value_bytes16(sqlite3_value*); 3461double sqlite3_value_double(sqlite3_value*); 3462int sqlite3_value_int(sqlite3_value*); 3463sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3464const unsigned char *sqlite3_value_text(sqlite3_value*); 3465const void *sqlite3_value_text16(sqlite3_value*); 3466const void *sqlite3_value_text16le(sqlite3_value*); 3467const void *sqlite3_value_text16be(sqlite3_value*); 3468int sqlite3_value_type(sqlite3_value*); 3469int sqlite3_value_numeric_type(sqlite3_value*); 3470 3471/* 3472** CAPI3REF: Obtain Aggregate Function Context 3473** 3474** Implementations of aggregate SQL functions use this 3475** routine to allocate memory for storing their state. 3476** 3477** ^The first time the sqlite3_aggregate_context(C,N) routine is called 3478** for a particular aggregate function, SQLite 3479** allocates N of memory, zeroes out that memory, and returns a pointer 3480** to the new memory. ^On second and subsequent calls to 3481** sqlite3_aggregate_context() for the same aggregate function instance, 3482** the same buffer is returned. Sqlite3_aggregate_context() is normally 3483** called once for each invocation of the xStep callback and then one 3484** last time when the xFinal callback is invoked. ^(When no rows match 3485** an aggregate query, the xStep() callback of the aggregate function 3486** implementation is never called and xFinal() is called exactly once. 3487** In those cases, sqlite3_aggregate_context() might be called for the 3488** first time from within xFinal().)^ 3489** 3490** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is 3491** less than or equal to zero or if a memory allocate error occurs. 3492** 3493** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 3494** determined by the N parameter on first successful call. Changing the 3495** value of N in subsequent call to sqlite3_aggregate_context() within 3496** the same aggregate function instance will not resize the memory 3497** allocation.)^ 3498** 3499** ^SQLite automatically frees the memory allocated by 3500** sqlite3_aggregate_context() when the aggregate query concludes. 3501** 3502** The first parameter must be a copy of the 3503** [sqlite3_context | SQL function context] that is the first parameter 3504** to the xStep or xFinal callback routine that implements the aggregate 3505** function. 3506** 3507** This routine must be called from the same thread in which 3508** the aggregate SQL function is running. 3509*/ 3510void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 3511 3512/* 3513** CAPI3REF: User Data For Functions 3514** 3515** ^The sqlite3_user_data() interface returns a copy of 3516** the pointer that was the pUserData parameter (the 5th parameter) 3517** of the [sqlite3_create_function()] 3518** and [sqlite3_create_function16()] routines that originally 3519** registered the application defined function. 3520** 3521** This routine must be called from the same thread in which 3522** the application-defined function is running. 3523*/ 3524void *sqlite3_user_data(sqlite3_context*); 3525 3526/* 3527** CAPI3REF: Database Connection For Functions 3528** 3529** ^The sqlite3_context_db_handle() interface returns a copy of 3530** the pointer to the [database connection] (the 1st parameter) 3531** of the [sqlite3_create_function()] 3532** and [sqlite3_create_function16()] routines that originally 3533** registered the application defined function. 3534*/ 3535sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 3536 3537/* 3538** CAPI3REF: Function Auxiliary Data 3539** 3540** The following two functions may be used by scalar SQL functions to 3541** associate metadata with argument values. If the same value is passed to 3542** multiple invocations of the same SQL function during query execution, under 3543** some circumstances the associated metadata may be preserved. This may 3544** be used, for example, to add a regular-expression matching scalar 3545** function. The compiled version of the regular expression is stored as 3546** metadata associated with the SQL value passed as the regular expression 3547** pattern. The compiled regular expression can be reused on multiple 3548** invocations of the same function so that the original pattern string 3549** does not need to be recompiled on each invocation. 3550** 3551** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 3552** associated by the sqlite3_set_auxdata() function with the Nth argument 3553** value to the application-defined function. ^If no metadata has been ever 3554** been set for the Nth argument of the function, or if the corresponding 3555** function parameter has changed since the meta-data was set, 3556** then sqlite3_get_auxdata() returns a NULL pointer. 3557** 3558** ^The sqlite3_set_auxdata() interface saves the metadata 3559** pointed to by its 3rd parameter as the metadata for the N-th 3560** argument of the application-defined function. Subsequent 3561** calls to sqlite3_get_auxdata() might return this data, if it has 3562** not been destroyed. 3563** ^If it is not NULL, SQLite will invoke the destructor 3564** function given by the 4th parameter to sqlite3_set_auxdata() on 3565** the metadata when the corresponding function parameter changes 3566** or when the SQL statement completes, whichever comes first. 3567** 3568** SQLite is free to call the destructor and drop metadata on any 3569** parameter of any function at any time. ^The only guarantee is that 3570** the destructor will be called before the metadata is dropped. 3571** 3572** ^(In practice, metadata is preserved between function calls for 3573** expressions that are constant at compile time. This includes literal 3574** values and [parameters].)^ 3575** 3576** These routines must be called from the same thread in which 3577** the SQL function is running. 3578*/ 3579void *sqlite3_get_auxdata(sqlite3_context*, int N); 3580void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 3581 3582 3583/* 3584** CAPI3REF: Constants Defining Special Destructor Behavior 3585** 3586** These are special values for the destructor that is passed in as the 3587** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 3588** argument is SQLITE_STATIC, it means that the content pointer is constant 3589** and will never change. It does not need to be destroyed. ^The 3590** SQLITE_TRANSIENT value means that the content will likely change in 3591** the near future and that SQLite should make its own private copy of 3592** the content before returning. 3593** 3594** The typedef is necessary to work around problems in certain 3595** C++ compilers. See ticket #2191. 3596*/ 3597typedef void (*sqlite3_destructor_type)(void*); 3598#define SQLITE_STATIC ((sqlite3_destructor_type)0) 3599#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 3600 3601/* 3602** CAPI3REF: Setting The Result Of An SQL Function 3603** 3604** These routines are used by the xFunc or xFinal callbacks that 3605** implement SQL functions and aggregates. See 3606** [sqlite3_create_function()] and [sqlite3_create_function16()] 3607** for additional information. 3608** 3609** These functions work very much like the [parameter binding] family of 3610** functions used to bind values to host parameters in prepared statements. 3611** Refer to the [SQL parameter] documentation for additional information. 3612** 3613** ^The sqlite3_result_blob() interface sets the result from 3614** an application-defined function to be the BLOB whose content is pointed 3615** to by the second parameter and which is N bytes long where N is the 3616** third parameter. 3617** 3618** ^The sqlite3_result_zeroblob() interfaces set the result of 3619** the application-defined function to be a BLOB containing all zero 3620** bytes and N bytes in size, where N is the value of the 2nd parameter. 3621** 3622** ^The sqlite3_result_double() interface sets the result from 3623** an application-defined function to be a floating point value specified 3624** by its 2nd argument. 3625** 3626** ^The sqlite3_result_error() and sqlite3_result_error16() functions 3627** cause the implemented SQL function to throw an exception. 3628** ^SQLite uses the string pointed to by the 3629** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 3630** as the text of an error message. ^SQLite interprets the error 3631** message string from sqlite3_result_error() as UTF-8. ^SQLite 3632** interprets the string from sqlite3_result_error16() as UTF-16 in native 3633** byte order. ^If the third parameter to sqlite3_result_error() 3634** or sqlite3_result_error16() is negative then SQLite takes as the error 3635** message all text up through the first zero character. 3636** ^If the third parameter to sqlite3_result_error() or 3637** sqlite3_result_error16() is non-negative then SQLite takes that many 3638** bytes (not characters) from the 2nd parameter as the error message. 3639** ^The sqlite3_result_error() and sqlite3_result_error16() 3640** routines make a private copy of the error message text before 3641** they return. Hence, the calling function can deallocate or 3642** modify the text after they return without harm. 3643** ^The sqlite3_result_error_code() function changes the error code 3644** returned by SQLite as a result of an error in a function. ^By default, 3645** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 3646** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 3647** 3648** ^The sqlite3_result_toobig() interface causes SQLite to throw an error 3649** indicating that a string or BLOB is too long to represent. 3650** 3651** ^The sqlite3_result_nomem() interface causes SQLite to throw an error 3652** indicating that a memory allocation failed. 3653** 3654** ^The sqlite3_result_int() interface sets the return value 3655** of the application-defined function to be the 32-bit signed integer 3656** value given in the 2nd argument. 3657** ^The sqlite3_result_int64() interface sets the return value 3658** of the application-defined function to be the 64-bit signed integer 3659** value given in the 2nd argument. 3660** 3661** ^The sqlite3_result_null() interface sets the return value 3662** of the application-defined function to be NULL. 3663** 3664** ^The sqlite3_result_text(), sqlite3_result_text16(), 3665** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 3666** set the return value of the application-defined function to be 3667** a text string which is represented as UTF-8, UTF-16 native byte order, 3668** UTF-16 little endian, or UTF-16 big endian, respectively. 3669** ^SQLite takes the text result from the application from 3670** the 2nd parameter of the sqlite3_result_text* interfaces. 3671** ^If the 3rd parameter to the sqlite3_result_text* interfaces 3672** is negative, then SQLite takes result text from the 2nd parameter 3673** through the first zero character. 3674** ^If the 3rd parameter to the sqlite3_result_text* interfaces 3675** is non-negative, then as many bytes (not characters) of the text 3676** pointed to by the 2nd parameter are taken as the application-defined 3677** function result. 3678** ^If the 4th parameter to the sqlite3_result_text* interfaces 3679** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 3680** function as the destructor on the text or BLOB result when it has 3681** finished using that result. 3682** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 3683** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 3684** assumes that the text or BLOB result is in constant space and does not 3685** copy the content of the parameter nor call a destructor on the content 3686** when it has finished using that result. 3687** ^If the 4th parameter to the sqlite3_result_text* interfaces 3688** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 3689** then SQLite makes a copy of the result into space obtained from 3690** from [sqlite3_malloc()] before it returns. 3691** 3692** ^The sqlite3_result_value() interface sets the result of 3693** the application-defined function to be a copy the 3694** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 3695** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 3696** so that the [sqlite3_value] specified in the parameter may change or 3697** be deallocated after sqlite3_result_value() returns without harm. 3698** ^A [protected sqlite3_value] object may always be used where an 3699** [unprotected sqlite3_value] object is required, so either 3700** kind of [sqlite3_value] object can be used with this interface. 3701** 3702** If these routines are called from within the different thread 3703** than the one containing the application-defined function that received 3704** the [sqlite3_context] pointer, the results are undefined. 3705*/ 3706void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 3707void sqlite3_result_double(sqlite3_context*, double); 3708void sqlite3_result_error(sqlite3_context*, const char*, int); 3709void sqlite3_result_error16(sqlite3_context*, const void*, int); 3710void sqlite3_result_error_toobig(sqlite3_context*); 3711void sqlite3_result_error_nomem(sqlite3_context*); 3712void sqlite3_result_error_code(sqlite3_context*, int); 3713void sqlite3_result_int(sqlite3_context*, int); 3714void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 3715void sqlite3_result_null(sqlite3_context*); 3716void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 3717void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 3718void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 3719void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 3720void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 3721void sqlite3_result_zeroblob(sqlite3_context*, int n); 3722 3723/* 3724** CAPI3REF: Define New Collating Sequences 3725** 3726** These functions are used to add new collation sequences to the 3727** [database connection] specified as the first argument. 3728** 3729** ^The name of the new collation sequence is specified as a UTF-8 string 3730** for sqlite3_create_collation() and sqlite3_create_collation_v2() 3731** and a UTF-16 string for sqlite3_create_collation16(). ^In all cases 3732** the name is passed as the second function argument. 3733** 3734** ^The third argument may be one of the constants [SQLITE_UTF8], 3735** [SQLITE_UTF16LE], or [SQLITE_UTF16BE], indicating that the user-supplied 3736** routine expects to be passed pointers to strings encoded using UTF-8, 3737** UTF-16 little-endian, or UTF-16 big-endian, respectively. ^The 3738** third argument might also be [SQLITE_UTF16] to indicate that the routine 3739** expects pointers to be UTF-16 strings in the native byte order, or the 3740** argument can be [SQLITE_UTF16_ALIGNED] if the 3741** the routine expects pointers to 16-bit word aligned strings 3742** of UTF-16 in the native byte order. 3743** 3744** A pointer to the user supplied routine must be passed as the fifth 3745** argument. ^If it is NULL, this is the same as deleting the collation 3746** sequence (so that SQLite cannot call it any more). 3747** ^Each time the application supplied function is invoked, it is passed 3748** as its first parameter a copy of the void* passed as the fourth argument 3749** to sqlite3_create_collation() or sqlite3_create_collation16(). 3750** 3751** ^The remaining arguments to the application-supplied routine are two strings, 3752** each represented by a (length, data) pair and encoded in the encoding 3753** that was passed as the third argument when the collation sequence was 3754** registered. The application defined collation routine should 3755** return negative, zero or positive if the first string is less than, 3756** equal to, or greater than the second string. i.e. (STRING1 - STRING2). 3757** 3758** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 3759** except that it takes an extra argument which is a destructor for 3760** the collation. ^The destructor is called when the collation is 3761** destroyed and is passed a copy of the fourth parameter void* pointer 3762** of the sqlite3_create_collation_v2(). 3763** ^Collations are destroyed when they are overridden by later calls to the 3764** collation creation functions or when the [database connection] is closed 3765** using [sqlite3_close()]. 3766** 3767** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 3768*/ 3769int sqlite3_create_collation( 3770 sqlite3*, 3771 const char *zName, 3772 int eTextRep, 3773 void*, 3774 int(*xCompare)(void*,int,const void*,int,const void*) 3775); 3776int sqlite3_create_collation_v2( 3777 sqlite3*, 3778 const char *zName, 3779 int eTextRep, 3780 void*, 3781 int(*xCompare)(void*,int,const void*,int,const void*), 3782 void(*xDestroy)(void*) 3783); 3784int sqlite3_create_collation16( 3785 sqlite3*, 3786 const void *zName, 3787 int eTextRep, 3788 void*, 3789 int(*xCompare)(void*,int,const void*,int,const void*) 3790); 3791 3792/* 3793** CAPI3REF: Collation Needed Callbacks 3794** 3795** ^To avoid having to register all collation sequences before a database 3796** can be used, a single callback function may be registered with the 3797** [database connection] to be invoked whenever an undefined collation 3798** sequence is required. 3799** 3800** ^If the function is registered using the sqlite3_collation_needed() API, 3801** then it is passed the names of undefined collation sequences as strings 3802** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 3803** the names are passed as UTF-16 in machine native byte order. 3804** ^A call to either function replaces the existing collation-needed callback. 3805** 3806** ^(When the callback is invoked, the first argument passed is a copy 3807** of the second argument to sqlite3_collation_needed() or 3808** sqlite3_collation_needed16(). The second argument is the database 3809** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 3810** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 3811** sequence function required. The fourth parameter is the name of the 3812** required collation sequence.)^ 3813** 3814** The callback function should register the desired collation using 3815** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 3816** [sqlite3_create_collation_v2()]. 3817*/ 3818int sqlite3_collation_needed( 3819 sqlite3*, 3820 void*, 3821 void(*)(void*,sqlite3*,int eTextRep,const char*) 3822); 3823int sqlite3_collation_needed16( 3824 sqlite3*, 3825 void*, 3826 void(*)(void*,sqlite3*,int eTextRep,const void*) 3827); 3828 3829#ifdef SQLITE_HAS_CODEC 3830/* 3831** Specify the key for an encrypted database. This routine should be 3832** called right after sqlite3_open(). 3833** 3834** The code to implement this API is not available in the public release 3835** of SQLite. 3836*/ 3837int sqlite3_key( 3838 sqlite3 *db, /* Database to be rekeyed */ 3839 const void *pKey, int nKey /* The key */ 3840); 3841 3842/* 3843** Change the key on an open database. If the current database is not 3844** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 3845** database is decrypted. 3846** 3847** The code to implement this API is not available in the public release 3848** of SQLite. 3849*/ 3850int sqlite3_rekey( 3851 sqlite3 *db, /* Database to be rekeyed */ 3852 const void *pKey, int nKey /* The new key */ 3853); 3854 3855/* 3856** Specify the activation key for a SEE database. Unless 3857** activated, none of the SEE routines will work. 3858*/ 3859void sqlite3_activate_see( 3860 const char *zPassPhrase /* Activation phrase */ 3861); 3862#endif 3863 3864#ifdef SQLITE_ENABLE_CEROD 3865/* 3866** Specify the activation key for a CEROD database. Unless 3867** activated, none of the CEROD routines will work. 3868*/ 3869void sqlite3_activate_cerod( 3870 const char *zPassPhrase /* Activation phrase */ 3871); 3872#endif 3873 3874/* 3875** CAPI3REF: Suspend Execution For A Short Time 3876** 3877** ^The sqlite3_sleep() function causes the current thread to suspend execution 3878** for at least a number of milliseconds specified in its parameter. 3879** 3880** ^If the operating system does not support sleep requests with 3881** millisecond time resolution, then the time will be rounded up to 3882** the nearest second. ^The number of milliseconds of sleep actually 3883** requested from the operating system is returned. 3884** 3885** ^SQLite implements this interface by calling the xSleep() 3886** method of the default [sqlite3_vfs] object. 3887*/ 3888int sqlite3_sleep(int); 3889 3890/* 3891** CAPI3REF: Name Of The Folder Holding Temporary Files 3892** 3893** ^(If this global variable is made to point to a string which is 3894** the name of a folder (a.k.a. directory), then all temporary files 3895** created by SQLite when using a built-in [sqlite3_vfs | VFS] 3896** will be placed in that directory.)^ ^If this variable 3897** is a NULL pointer, then SQLite performs a search for an appropriate 3898** temporary file directory. 3899** 3900** It is not safe to read or modify this variable in more than one 3901** thread at a time. It is not safe to read or modify this variable 3902** if a [database connection] is being used at the same time in a separate 3903** thread. 3904** It is intended that this variable be set once 3905** as part of process initialization and before any SQLite interface 3906** routines have been called and that this variable remain unchanged 3907** thereafter. 3908** 3909** ^The [temp_store_directory pragma] may modify this variable and cause 3910** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 3911** the [temp_store_directory pragma] always assumes that any string 3912** that this variable points to is held in memory obtained from 3913** [sqlite3_malloc] and the pragma may attempt to free that memory 3914** using [sqlite3_free]. 3915** Hence, if this variable is modified directly, either it should be 3916** made NULL or made to point to memory obtained from [sqlite3_malloc] 3917** or else the use of the [temp_store_directory pragma] should be avoided. 3918*/ 3919SQLITE_EXTERN char *sqlite3_temp_directory; 3920 3921/* 3922** CAPI3REF: Test For Auto-Commit Mode 3923** KEYWORDS: {autocommit mode} 3924** 3925** ^The sqlite3_get_autocommit() interface returns non-zero or 3926** zero if the given database connection is or is not in autocommit mode, 3927** respectively. ^Autocommit mode is on by default. 3928** ^Autocommit mode is disabled by a [BEGIN] statement. 3929** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 3930** 3931** If certain kinds of errors occur on a statement within a multi-statement 3932** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 3933** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 3934** transaction might be rolled back automatically. The only way to 3935** find out whether SQLite automatically rolled back the transaction after 3936** an error is to use this function. 3937** 3938** If another thread changes the autocommit status of the database 3939** connection while this routine is running, then the return value 3940** is undefined. 3941*/ 3942int sqlite3_get_autocommit(sqlite3*); 3943 3944/* 3945** CAPI3REF: Find The Database Handle Of A Prepared Statement 3946** 3947** ^The sqlite3_db_handle interface returns the [database connection] handle 3948** to which a [prepared statement] belongs. ^The [database connection] 3949** returned by sqlite3_db_handle is the same [database connection] 3950** that was the first argument 3951** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 3952** create the statement in the first place. 3953*/ 3954sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 3955 3956/* 3957** CAPI3REF: Find the next prepared statement 3958** 3959** ^This interface returns a pointer to the next [prepared statement] after 3960** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 3961** then this interface returns a pointer to the first prepared statement 3962** associated with the database connection pDb. ^If no prepared statement 3963** satisfies the conditions of this routine, it returns NULL. 3964** 3965** The [database connection] pointer D in a call to 3966** [sqlite3_next_stmt(D,S)] must refer to an open database 3967** connection and in particular must not be a NULL pointer. 3968*/ 3969sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 3970 3971/* 3972** CAPI3REF: Commit And Rollback Notification Callbacks 3973** 3974** ^The sqlite3_commit_hook() interface registers a callback 3975** function to be invoked whenever a transaction is [COMMIT | committed]. 3976** ^Any callback set by a previous call to sqlite3_commit_hook() 3977** for the same database connection is overridden. 3978** ^The sqlite3_rollback_hook() interface registers a callback 3979** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 3980** ^Any callback set by a previous call to sqlite3_rollback_hook() 3981** for the same database connection is overridden. 3982** ^The pArg argument is passed through to the callback. 3983** ^If the callback on a commit hook function returns non-zero, 3984** then the commit is converted into a rollback. 3985** 3986** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 3987** return the P argument from the previous call of the same function 3988** on the same [database connection] D, or NULL for 3989** the first call for each function on D. 3990** 3991** The callback implementation must not do anything that will modify 3992** the database connection that invoked the callback. Any actions 3993** to modify the database connection must be deferred until after the 3994** completion of the [sqlite3_step()] call that triggered the commit 3995** or rollback hook in the first place. 3996** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3997** database connections for the meaning of "modify" in this paragraph. 3998** 3999** ^Registering a NULL function disables the callback. 4000** 4001** ^When the commit hook callback routine returns zero, the [COMMIT] 4002** operation is allowed to continue normally. ^If the commit hook 4003** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 4004** ^The rollback hook is invoked on a rollback that results from a commit 4005** hook returning non-zero, just as it would be with any other rollback. 4006** 4007** ^For the purposes of this API, a transaction is said to have been 4008** rolled back if an explicit "ROLLBACK" statement is executed, or 4009** an error or constraint causes an implicit rollback to occur. 4010** ^The rollback callback is not invoked if a transaction is 4011** automatically rolled back because the database connection is closed. 4012** 4013** See also the [sqlite3_update_hook()] interface. 4014*/ 4015void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 4016void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 4017 4018/* 4019** CAPI3REF: Data Change Notification Callbacks 4020** 4021** ^The sqlite3_update_hook() interface registers a callback function 4022** with the [database connection] identified by the first argument 4023** to be invoked whenever a row is updated, inserted or deleted. 4024** ^Any callback set by a previous call to this function 4025** for the same database connection is overridden. 4026** 4027** ^The second argument is a pointer to the function to invoke when a 4028** row is updated, inserted or deleted. 4029** ^The first argument to the callback is a copy of the third argument 4030** to sqlite3_update_hook(). 4031** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 4032** or [SQLITE_UPDATE], depending on the operation that caused the callback 4033** to be invoked. 4034** ^The third and fourth arguments to the callback contain pointers to the 4035** database and table name containing the affected row. 4036** ^The final callback parameter is the [rowid] of the row. 4037** ^In the case of an update, this is the [rowid] after the update takes place. 4038** 4039** ^(The update hook is not invoked when internal system tables are 4040** modified (i.e. sqlite_master and sqlite_sequence).)^ 4041** 4042** ^In the current implementation, the update hook 4043** is not invoked when duplication rows are deleted because of an 4044** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 4045** invoked when rows are deleted using the [truncate optimization]. 4046** The exceptions defined in this paragraph might change in a future 4047** release of SQLite. 4048** 4049** The update hook implementation must not do anything that will modify 4050** the database connection that invoked the update hook. Any actions 4051** to modify the database connection must be deferred until after the 4052** completion of the [sqlite3_step()] call that triggered the update hook. 4053** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4054** database connections for the meaning of "modify" in this paragraph. 4055** 4056** ^The sqlite3_update_hook(D,C,P) function 4057** returns the P argument from the previous call 4058** on the same [database connection] D, or NULL for 4059** the first call on D. 4060** 4061** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4062** interfaces. 4063*/ 4064void *sqlite3_update_hook( 4065 sqlite3*, 4066 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4067 void* 4068); 4069 4070/* 4071** CAPI3REF: Enable Or Disable Shared Pager Cache 4072** KEYWORDS: {shared cache} 4073** 4074** ^(This routine enables or disables the sharing of the database cache 4075** and schema data structures between [database connection | connections] 4076** to the same database. Sharing is enabled if the argument is true 4077** and disabled if the argument is false.)^ 4078** 4079** ^Cache sharing is enabled and disabled for an entire process. 4080** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4081** sharing was enabled or disabled for each thread separately. 4082** 4083** ^(The cache sharing mode set by this interface effects all subsequent 4084** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4085** Existing database connections continue use the sharing mode 4086** that was in effect at the time they were opened.)^ 4087** 4088** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4089** successfully. An [error code] is returned otherwise.)^ 4090** 4091** ^Shared cache is disabled by default. But this might change in 4092** future releases of SQLite. Applications that care about shared 4093** cache setting should set it explicitly. 4094** 4095** See Also: [SQLite Shared-Cache Mode] 4096*/ 4097int sqlite3_enable_shared_cache(int); 4098 4099/* 4100** CAPI3REF: Attempt To Free Heap Memory 4101** 4102** ^The sqlite3_release_memory() interface attempts to free N bytes 4103** of heap memory by deallocating non-essential memory allocations 4104** held by the database library. Memory used to cache database 4105** pages to improve performance is an example of non-essential memory. 4106** ^sqlite3_release_memory() returns the number of bytes actually freed, 4107** which might be more or less than the amount requested. 4108** ^The sqlite3_release_memory() routine is a no-op returning zero 4109** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4110*/ 4111int sqlite3_release_memory(int); 4112 4113/* 4114** CAPI3REF: Impose A Limit On Heap Size 4115** 4116** ^The sqlite3_soft_heap_limit() interface places a "soft" limit 4117** on the amount of heap memory that may be allocated by SQLite. 4118** ^If an internal allocation is requested that would exceed the 4119** soft heap limit, [sqlite3_release_memory()] is invoked one or 4120** more times to free up some space before the allocation is performed. 4121** 4122** ^The limit is called "soft" because if [sqlite3_release_memory()] 4123** cannot free sufficient memory to prevent the limit from being exceeded, 4124** the memory is allocated anyway and the current operation proceeds. 4125** 4126** ^A negative or zero value for N means that there is no soft heap limit and 4127** [sqlite3_release_memory()] will only be called when memory is exhausted. 4128** ^The default value for the soft heap limit is zero. 4129** 4130** ^(SQLite makes a best effort to honor the soft heap limit. 4131** But if the soft heap limit cannot be honored, execution will 4132** continue without error or notification.)^ This is why the limit is 4133** called a "soft" limit. It is advisory only. 4134** 4135** Prior to SQLite version 3.5.0, this routine only constrained the memory 4136** allocated by a single thread - the same thread in which this routine 4137** runs. Beginning with SQLite version 3.5.0, the soft heap limit is 4138** applied to all threads. The value specified for the soft heap limit 4139** is an upper bound on the total memory allocation for all threads. In 4140** version 3.5.0 there is no mechanism for limiting the heap usage for 4141** individual threads. 4142*/ 4143void sqlite3_soft_heap_limit(int); 4144 4145/* 4146** CAPI3REF: Extract Metadata About A Column Of A Table 4147** 4148** ^This routine returns metadata about a specific column of a specific 4149** database table accessible using the [database connection] handle 4150** passed as the first function argument. 4151** 4152** ^The column is identified by the second, third and fourth parameters to 4153** this function. ^The second parameter is either the name of the database 4154** (i.e. "main", "temp", or an attached database) containing the specified 4155** table or NULL. ^If it is NULL, then all attached databases are searched 4156** for the table using the same algorithm used by the database engine to 4157** resolve unqualified table references. 4158** 4159** ^The third and fourth parameters to this function are the table and column 4160** name of the desired column, respectively. Neither of these parameters 4161** may be NULL. 4162** 4163** ^Metadata is returned by writing to the memory locations passed as the 5th 4164** and subsequent parameters to this function. ^Any of these arguments may be 4165** NULL, in which case the corresponding element of metadata is omitted. 4166** 4167** ^(<blockquote> 4168** <table border="1"> 4169** <tr><th> Parameter <th> Output<br>Type <th> Description 4170** 4171** <tr><td> 5th <td> const char* <td> Data type 4172** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4173** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4174** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4175** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4176** </table> 4177** </blockquote>)^ 4178** 4179** ^The memory pointed to by the character pointers returned for the 4180** declaration type and collation sequence is valid only until the next 4181** call to any SQLite API function. 4182** 4183** ^If the specified table is actually a view, an [error code] is returned. 4184** 4185** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4186** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4187** parameters are set for the explicitly declared column. ^(If there is no 4188** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4189** parameters are set as follows: 4190** 4191** <pre> 4192** data type: "INTEGER" 4193** collation sequence: "BINARY" 4194** not null: 0 4195** primary key: 1 4196** auto increment: 0 4197** </pre>)^ 4198** 4199** ^(This function may load one or more schemas from database files. If an 4200** error occurs during this process, or if the requested table or column 4201** cannot be found, an [error code] is returned and an error message left 4202** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4203** 4204** ^This API is only available if the library was compiled with the 4205** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4206*/ 4207int sqlite3_table_column_metadata( 4208 sqlite3 *db, /* Connection handle */ 4209 const char *zDbName, /* Database name or NULL */ 4210 const char *zTableName, /* Table name */ 4211 const char *zColumnName, /* Column name */ 4212 char const **pzDataType, /* OUTPUT: Declared data type */ 4213 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4214 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4215 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4216 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4217); 4218 4219/* 4220** CAPI3REF: Load An Extension 4221** 4222** ^This interface loads an SQLite extension library from the named file. 4223** 4224** ^The sqlite3_load_extension() interface attempts to load an 4225** SQLite extension library contained in the file zFile. 4226** 4227** ^The entry point is zProc. 4228** ^zProc may be 0, in which case the name of the entry point 4229** defaults to "sqlite3_extension_init". 4230** ^The sqlite3_load_extension() interface returns 4231** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4232** ^If an error occurs and pzErrMsg is not 0, then the 4233** [sqlite3_load_extension()] interface shall attempt to 4234** fill *pzErrMsg with error message text stored in memory 4235** obtained from [sqlite3_malloc()]. The calling function 4236** should free this memory by calling [sqlite3_free()]. 4237** 4238** ^Extension loading must be enabled using 4239** [sqlite3_enable_load_extension()] prior to calling this API, 4240** otherwise an error will be returned. 4241** 4242** See also the [load_extension() SQL function]. 4243*/ 4244int sqlite3_load_extension( 4245 sqlite3 *db, /* Load the extension into this database connection */ 4246 const char *zFile, /* Name of the shared library containing extension */ 4247 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4248 char **pzErrMsg /* Put error message here if not 0 */ 4249); 4250 4251/* 4252** CAPI3REF: Enable Or Disable Extension Loading 4253** 4254** ^So as not to open security holes in older applications that are 4255** unprepared to deal with extension loading, and as a means of disabling 4256** extension loading while evaluating user-entered SQL, the following API 4257** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4258** 4259** ^Extension loading is off by default. See ticket #1863. 4260** ^Call the sqlite3_enable_load_extension() routine with onoff==1 4261** to turn extension loading on and call it with onoff==0 to turn 4262** it back off again. 4263*/ 4264int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4265 4266/* 4267** CAPI3REF: Automatically Load An Extensions 4268** 4269** ^This API can be invoked at program startup in order to register 4270** one or more statically linked extensions that will be available 4271** to all new [database connections]. 4272** 4273** ^(This routine stores a pointer to the extension entry point 4274** in an array that is obtained from [sqlite3_malloc()]. That memory 4275** is deallocated by [sqlite3_reset_auto_extension()].)^ 4276** 4277** ^This function registers an extension entry point that is 4278** automatically invoked whenever a new [database connection] 4279** is opened using [sqlite3_open()], [sqlite3_open16()], 4280** or [sqlite3_open_v2()]. 4281** ^Duplicate extensions are detected so calling this routine 4282** multiple times with the same extension is harmless. 4283** ^Automatic extensions apply across all threads. 4284*/ 4285int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4286 4287/* 4288** CAPI3REF: Reset Automatic Extension Loading 4289** 4290** ^(This function disables all previously registered automatic 4291** extensions. It undoes the effect of all prior 4292** [sqlite3_auto_extension()] calls.)^ 4293** 4294** ^This function disables automatic extensions in all threads. 4295*/ 4296void sqlite3_reset_auto_extension(void); 4297 4298/* 4299** The interface to the virtual-table mechanism is currently considered 4300** to be experimental. The interface might change in incompatible ways. 4301** If this is a problem for you, do not use the interface at this time. 4302** 4303** When the virtual-table mechanism stabilizes, we will declare the 4304** interface fixed, support it indefinitely, and remove this comment. 4305*/ 4306 4307/* 4308** Structures used by the virtual table interface 4309*/ 4310typedef struct sqlite3_vtab sqlite3_vtab; 4311typedef struct sqlite3_index_info sqlite3_index_info; 4312typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4313typedef struct sqlite3_module sqlite3_module; 4314 4315/* 4316** CAPI3REF: Virtual Table Object 4317** KEYWORDS: sqlite3_module {virtual table module} 4318** 4319** This structure, sometimes called a a "virtual table module", 4320** defines the implementation of a [virtual tables]. 4321** This structure consists mostly of methods for the module. 4322** 4323** ^A virtual table module is created by filling in a persistent 4324** instance of this structure and passing a pointer to that instance 4325** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4326** ^The registration remains valid until it is replaced by a different 4327** module or until the [database connection] closes. The content 4328** of this structure must not change while it is registered with 4329** any database connection. 4330*/ 4331struct sqlite3_module { 4332 int iVersion; 4333 int (*xCreate)(sqlite3*, void *pAux, 4334 int argc, const char *const*argv, 4335 sqlite3_vtab **ppVTab, char**); 4336 int (*xConnect)(sqlite3*, void *pAux, 4337 int argc, const char *const*argv, 4338 sqlite3_vtab **ppVTab, char**); 4339 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4340 int (*xDisconnect)(sqlite3_vtab *pVTab); 4341 int (*xDestroy)(sqlite3_vtab *pVTab); 4342 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4343 int (*xClose)(sqlite3_vtab_cursor*); 4344 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4345 int argc, sqlite3_value **argv); 4346 int (*xNext)(sqlite3_vtab_cursor*); 4347 int (*xEof)(sqlite3_vtab_cursor*); 4348 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4349 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4350 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4351 int (*xBegin)(sqlite3_vtab *pVTab); 4352 int (*xSync)(sqlite3_vtab *pVTab); 4353 int (*xCommit)(sqlite3_vtab *pVTab); 4354 int (*xRollback)(sqlite3_vtab *pVTab); 4355 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4356 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4357 void **ppArg); 4358 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4359}; 4360 4361/* 4362** CAPI3REF: Virtual Table Indexing Information 4363** KEYWORDS: sqlite3_index_info 4364** 4365** The sqlite3_index_info structure and its substructures is used as part 4366** of the [virtual table] interface to 4367** pass information into and receive the reply from the [xBestIndex] 4368** method of a [virtual table module]. The fields under **Inputs** are the 4369** inputs to xBestIndex and are read-only. xBestIndex inserts its 4370** results into the **Outputs** fields. 4371** 4372** ^(The aConstraint[] array records WHERE clause constraints of the form: 4373** 4374** <blockquote>column OP expr</blockquote> 4375** 4376** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 4377** stored in aConstraint[].op using one of the 4378** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 4379** ^(The index of the column is stored in 4380** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 4381** expr on the right-hand side can be evaluated (and thus the constraint 4382** is usable) and false if it cannot.)^ 4383** 4384** ^The optimizer automatically inverts terms of the form "expr OP column" 4385** and makes other simplifications to the WHERE clause in an attempt to 4386** get as many WHERE clause terms into the form shown above as possible. 4387** ^The aConstraint[] array only reports WHERE clause terms that are 4388** relevant to the particular virtual table being queried. 4389** 4390** ^Information about the ORDER BY clause is stored in aOrderBy[]. 4391** ^Each term of aOrderBy records a column of the ORDER BY clause. 4392** 4393** The [xBestIndex] method must fill aConstraintUsage[] with information 4394** about what parameters to pass to xFilter. ^If argvIndex>0 then 4395** the right-hand side of the corresponding aConstraint[] is evaluated 4396** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 4397** is true, then the constraint is assumed to be fully handled by the 4398** virtual table and is not checked again by SQLite.)^ 4399** 4400** ^The idxNum and idxPtr values are recorded and passed into the 4401** [xFilter] method. 4402** ^[sqlite3_free()] is used to free idxPtr if and only if 4403** needToFreeIdxPtr is true. 4404** 4405** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 4406** the correct order to satisfy the ORDER BY clause so that no separate 4407** sorting step is required. 4408** 4409** ^The estimatedCost value is an estimate of the cost of doing the 4410** particular lookup. A full scan of a table with N entries should have 4411** a cost of N. A binary search of a table of N entries should have a 4412** cost of approximately log(N). 4413*/ 4414struct sqlite3_index_info { 4415 /* Inputs */ 4416 int nConstraint; /* Number of entries in aConstraint */ 4417 struct sqlite3_index_constraint { 4418 int iColumn; /* Column on left-hand side of constraint */ 4419 unsigned char op; /* Constraint operator */ 4420 unsigned char usable; /* True if this constraint is usable */ 4421 int iTermOffset; /* Used internally - xBestIndex should ignore */ 4422 } *aConstraint; /* Table of WHERE clause constraints */ 4423 int nOrderBy; /* Number of terms in the ORDER BY clause */ 4424 struct sqlite3_index_orderby { 4425 int iColumn; /* Column number */ 4426 unsigned char desc; /* True for DESC. False for ASC. */ 4427 } *aOrderBy; /* The ORDER BY clause */ 4428 /* Outputs */ 4429 struct sqlite3_index_constraint_usage { 4430 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 4431 unsigned char omit; /* Do not code a test for this constraint */ 4432 } *aConstraintUsage; 4433 int idxNum; /* Number used to identify the index */ 4434 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 4435 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 4436 int orderByConsumed; /* True if output is already ordered */ 4437 double estimatedCost; /* Estimated cost of using this index */ 4438}; 4439 4440/* 4441** CAPI3REF: Virtual Table Constraint Operator Codes 4442** 4443** These macros defined the allowed values for the 4444** [sqlite3_index_info].aConstraint[].op field. Each value represents 4445** an operator that is part of a constraint term in the wHERE clause of 4446** a query that uses a [virtual table]. 4447*/ 4448#define SQLITE_INDEX_CONSTRAINT_EQ 2 4449#define SQLITE_INDEX_CONSTRAINT_GT 4 4450#define SQLITE_INDEX_CONSTRAINT_LE 8 4451#define SQLITE_INDEX_CONSTRAINT_LT 16 4452#define SQLITE_INDEX_CONSTRAINT_GE 32 4453#define SQLITE_INDEX_CONSTRAINT_MATCH 64 4454 4455/* 4456** CAPI3REF: Register A Virtual Table Implementation 4457** 4458** ^These routines are used to register a new [virtual table module] name. 4459** ^Module names must be registered before 4460** creating a new [virtual table] using the module and before using a 4461** preexisting [virtual table] for the module. 4462** 4463** ^The module name is registered on the [database connection] specified 4464** by the first parameter. ^The name of the module is given by the 4465** second parameter. ^The third parameter is a pointer to 4466** the implementation of the [virtual table module]. ^The fourth 4467** parameter is an arbitrary client data pointer that is passed through 4468** into the [xCreate] and [xConnect] methods of the virtual table module 4469** when a new virtual table is be being created or reinitialized. 4470** 4471** ^The sqlite3_create_module_v2() interface has a fifth parameter which 4472** is a pointer to a destructor for the pClientData. ^SQLite will 4473** invoke the destructor function (if it is not NULL) when SQLite 4474** no longer needs the pClientData pointer. ^The sqlite3_create_module() 4475** interface is equivalent to sqlite3_create_module_v2() with a NULL 4476** destructor. 4477*/ 4478int sqlite3_create_module( 4479 sqlite3 *db, /* SQLite connection to register module with */ 4480 const char *zName, /* Name of the module */ 4481 const sqlite3_module *p, /* Methods for the module */ 4482 void *pClientData /* Client data for xCreate/xConnect */ 4483); 4484int sqlite3_create_module_v2( 4485 sqlite3 *db, /* SQLite connection to register module with */ 4486 const char *zName, /* Name of the module */ 4487 const sqlite3_module *p, /* Methods for the module */ 4488 void *pClientData, /* Client data for xCreate/xConnect */ 4489 void(*xDestroy)(void*) /* Module destructor function */ 4490); 4491 4492/* 4493** CAPI3REF: Virtual Table Instance Object 4494** KEYWORDS: sqlite3_vtab 4495** 4496** Every [virtual table module] implementation uses a subclass 4497** of this object to describe a particular instance 4498** of the [virtual table]. Each subclass will 4499** be tailored to the specific needs of the module implementation. 4500** The purpose of this superclass is to define certain fields that are 4501** common to all module implementations. 4502** 4503** ^Virtual tables methods can set an error message by assigning a 4504** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 4505** take care that any prior string is freed by a call to [sqlite3_free()] 4506** prior to assigning a new string to zErrMsg. ^After the error message 4507** is delivered up to the client application, the string will be automatically 4508** freed by sqlite3_free() and the zErrMsg field will be zeroed. 4509*/ 4510struct sqlite3_vtab { 4511 const sqlite3_module *pModule; /* The module for this virtual table */ 4512 int nRef; /* NO LONGER USED */ 4513 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 4514 /* Virtual table implementations will typically add additional fields */ 4515}; 4516 4517/* 4518** CAPI3REF: Virtual Table Cursor Object 4519** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 4520** 4521** Every [virtual table module] implementation uses a subclass of the 4522** following structure to describe cursors that point into the 4523** [virtual table] and are used 4524** to loop through the virtual table. Cursors are created using the 4525** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 4526** by the [sqlite3_module.xClose | xClose] method. Cursors are used 4527** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 4528** of the module. Each module implementation will define 4529** the content of a cursor structure to suit its own needs. 4530** 4531** This superclass exists in order to define fields of the cursor that 4532** are common to all implementations. 4533*/ 4534struct sqlite3_vtab_cursor { 4535 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 4536 /* Virtual table implementations will typically add additional fields */ 4537}; 4538 4539/* 4540** CAPI3REF: Declare The Schema Of A Virtual Table 4541** 4542** ^The [xCreate] and [xConnect] methods of a 4543** [virtual table module] call this interface 4544** to declare the format (the names and datatypes of the columns) of 4545** the virtual tables they implement. 4546*/ 4547int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 4548 4549/* 4550** CAPI3REF: Overload A Function For A Virtual Table 4551** 4552** ^(Virtual tables can provide alternative implementations of functions 4553** using the [xFindFunction] method of the [virtual table module]. 4554** But global versions of those functions 4555** must exist in order to be overloaded.)^ 4556** 4557** ^(This API makes sure a global version of a function with a particular 4558** name and number of parameters exists. If no such function exists 4559** before this API is called, a new function is created.)^ ^The implementation 4560** of the new function always causes an exception to be thrown. So 4561** the new function is not good for anything by itself. Its only 4562** purpose is to be a placeholder function that can be overloaded 4563** by a [virtual table]. 4564*/ 4565int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 4566 4567/* 4568** The interface to the virtual-table mechanism defined above (back up 4569** to a comment remarkably similar to this one) is currently considered 4570** to be experimental. The interface might change in incompatible ways. 4571** If this is a problem for you, do not use the interface at this time. 4572** 4573** When the virtual-table mechanism stabilizes, we will declare the 4574** interface fixed, support it indefinitely, and remove this comment. 4575*/ 4576 4577/* 4578** CAPI3REF: A Handle To An Open BLOB 4579** KEYWORDS: {BLOB handle} {BLOB handles} 4580** 4581** An instance of this object represents an open BLOB on which 4582** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 4583** ^Objects of this type are created by [sqlite3_blob_open()] 4584** and destroyed by [sqlite3_blob_close()]. 4585** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 4586** can be used to read or write small subsections of the BLOB. 4587** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 4588*/ 4589typedef struct sqlite3_blob sqlite3_blob; 4590 4591/* 4592** CAPI3REF: Open A BLOB For Incremental I/O 4593** 4594** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 4595** in row iRow, column zColumn, table zTable in database zDb; 4596** in other words, the same BLOB that would be selected by: 4597** 4598** <pre> 4599** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 4600** </pre>)^ 4601** 4602** ^If the flags parameter is non-zero, then the BLOB is opened for read 4603** and write access. ^If it is zero, the BLOB is opened for read access. 4604** ^It is not possible to open a column that is part of an index or primary 4605** key for writing. ^If [foreign key constraints] are enabled, it is 4606** not possible to open a column that is part of a [child key] for writing. 4607** 4608** ^Note that the database name is not the filename that contains 4609** the database but rather the symbolic name of the database that 4610** appears after the AS keyword when the database is connected using [ATTACH]. 4611** ^For the main database file, the database name is "main". 4612** ^For TEMP tables, the database name is "temp". 4613** 4614** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 4615** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 4616** to be a null pointer.)^ 4617** ^This function sets the [database connection] error code and message 4618** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 4619** functions. ^Note that the *ppBlob variable is always initialized in a 4620** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 4621** regardless of the success or failure of this routine. 4622** 4623** ^(If the row that a BLOB handle points to is modified by an 4624** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 4625** then the BLOB handle is marked as "expired". 4626** This is true if any column of the row is changed, even a column 4627** other than the one the BLOB handle is open on.)^ 4628** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 4629** a expired BLOB handle fail with an return code of [SQLITE_ABORT]. 4630** ^(Changes written into a BLOB prior to the BLOB expiring are not 4631** rolled back by the expiration of the BLOB. Such changes will eventually 4632** commit if the transaction continues to completion.)^ 4633** 4634** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 4635** the opened blob. ^The size of a blob may not be changed by this 4636** interface. Use the [UPDATE] SQL command to change the size of a 4637** blob. 4638** 4639** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 4640** and the built-in [zeroblob] SQL function can be used, if desired, 4641** to create an empty, zero-filled blob in which to read or write using 4642** this interface. 4643** 4644** To avoid a resource leak, every open [BLOB handle] should eventually 4645** be released by a call to [sqlite3_blob_close()]. 4646*/ 4647int sqlite3_blob_open( 4648 sqlite3*, 4649 const char *zDb, 4650 const char *zTable, 4651 const char *zColumn, 4652 sqlite3_int64 iRow, 4653 int flags, 4654 sqlite3_blob **ppBlob 4655); 4656 4657/* 4658** CAPI3REF: Close A BLOB Handle 4659** 4660** ^Closes an open [BLOB handle]. 4661** 4662** ^Closing a BLOB shall cause the current transaction to commit 4663** if there are no other BLOBs, no pending prepared statements, and the 4664** database connection is in [autocommit mode]. 4665** ^If any writes were made to the BLOB, they might be held in cache 4666** until the close operation if they will fit. 4667** 4668** ^(Closing the BLOB often forces the changes 4669** out to disk and so if any I/O errors occur, they will likely occur 4670** at the time when the BLOB is closed. Any errors that occur during 4671** closing are reported as a non-zero return value.)^ 4672** 4673** ^(The BLOB is closed unconditionally. Even if this routine returns 4674** an error code, the BLOB is still closed.)^ 4675** 4676** ^Calling this routine with a null pointer (such as would be returned 4677** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 4678*/ 4679int sqlite3_blob_close(sqlite3_blob *); 4680 4681/* 4682** CAPI3REF: Return The Size Of An Open BLOB 4683** 4684** ^Returns the size in bytes of the BLOB accessible via the 4685** successfully opened [BLOB handle] in its only argument. ^The 4686** incremental blob I/O routines can only read or overwriting existing 4687** blob content; they cannot change the size of a blob. 4688** 4689** This routine only works on a [BLOB handle] which has been created 4690** by a prior successful call to [sqlite3_blob_open()] and which has not 4691** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4692** to this routine results in undefined and probably undesirable behavior. 4693*/ 4694int sqlite3_blob_bytes(sqlite3_blob *); 4695 4696/* 4697** CAPI3REF: Read Data From A BLOB Incrementally 4698** 4699** ^(This function is used to read data from an open [BLOB handle] into a 4700** caller-supplied buffer. N bytes of data are copied into buffer Z 4701** from the open BLOB, starting at offset iOffset.)^ 4702** 4703** ^If offset iOffset is less than N bytes from the end of the BLOB, 4704** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 4705** less than zero, [SQLITE_ERROR] is returned and no data is read. 4706** ^The size of the blob (and hence the maximum value of N+iOffset) 4707** can be determined using the [sqlite3_blob_bytes()] interface. 4708** 4709** ^An attempt to read from an expired [BLOB handle] fails with an 4710** error code of [SQLITE_ABORT]. 4711** 4712** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 4713** Otherwise, an [error code] or an [extended error code] is returned.)^ 4714** 4715** This routine only works on a [BLOB handle] which has been created 4716** by a prior successful call to [sqlite3_blob_open()] and which has not 4717** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4718** to this routine results in undefined and probably undesirable behavior. 4719** 4720** See also: [sqlite3_blob_write()]. 4721*/ 4722int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 4723 4724/* 4725** CAPI3REF: Write Data Into A BLOB Incrementally 4726** 4727** ^This function is used to write data into an open [BLOB handle] from a 4728** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 4729** into the open BLOB, starting at offset iOffset. 4730** 4731** ^If the [BLOB handle] passed as the first argument was not opened for 4732** writing (the flags parameter to [sqlite3_blob_open()] was zero), 4733** this function returns [SQLITE_READONLY]. 4734** 4735** ^This function may only modify the contents of the BLOB; it is 4736** not possible to increase the size of a BLOB using this API. 4737** ^If offset iOffset is less than N bytes from the end of the BLOB, 4738** [SQLITE_ERROR] is returned and no data is written. ^If N is 4739** less than zero [SQLITE_ERROR] is returned and no data is written. 4740** The size of the BLOB (and hence the maximum value of N+iOffset) 4741** can be determined using the [sqlite3_blob_bytes()] interface. 4742** 4743** ^An attempt to write to an expired [BLOB handle] fails with an 4744** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 4745** before the [BLOB handle] expired are not rolled back by the 4746** expiration of the handle, though of course those changes might 4747** have been overwritten by the statement that expired the BLOB handle 4748** or by other independent statements. 4749** 4750** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 4751** Otherwise, an [error code] or an [extended error code] is returned.)^ 4752** 4753** This routine only works on a [BLOB handle] which has been created 4754** by a prior successful call to [sqlite3_blob_open()] and which has not 4755** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4756** to this routine results in undefined and probably undesirable behavior. 4757** 4758** See also: [sqlite3_blob_read()]. 4759*/ 4760int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 4761 4762/* 4763** CAPI3REF: Virtual File System Objects 4764** 4765** A virtual filesystem (VFS) is an [sqlite3_vfs] object 4766** that SQLite uses to interact 4767** with the underlying operating system. Most SQLite builds come with a 4768** single default VFS that is appropriate for the host computer. 4769** New VFSes can be registered and existing VFSes can be unregistered. 4770** The following interfaces are provided. 4771** 4772** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 4773** ^Names are case sensitive. 4774** ^Names are zero-terminated UTF-8 strings. 4775** ^If there is no match, a NULL pointer is returned. 4776** ^If zVfsName is NULL then the default VFS is returned. 4777** 4778** ^New VFSes are registered with sqlite3_vfs_register(). 4779** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 4780** ^The same VFS can be registered multiple times without injury. 4781** ^To make an existing VFS into the default VFS, register it again 4782** with the makeDflt flag set. If two different VFSes with the 4783** same name are registered, the behavior is undefined. If a 4784** VFS is registered with a name that is NULL or an empty string, 4785** then the behavior is undefined. 4786** 4787** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 4788** ^(If the default VFS is unregistered, another VFS is chosen as 4789** the default. The choice for the new VFS is arbitrary.)^ 4790*/ 4791sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 4792int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 4793int sqlite3_vfs_unregister(sqlite3_vfs*); 4794 4795/* 4796** CAPI3REF: Mutexes 4797** 4798** The SQLite core uses these routines for thread 4799** synchronization. Though they are intended for internal 4800** use by SQLite, code that links against SQLite is 4801** permitted to use any of these routines. 4802** 4803** The SQLite source code contains multiple implementations 4804** of these mutex routines. An appropriate implementation 4805** is selected automatically at compile-time. ^(The following 4806** implementations are available in the SQLite core: 4807** 4808** <ul> 4809** <li> SQLITE_MUTEX_OS2 4810** <li> SQLITE_MUTEX_PTHREAD 4811** <li> SQLITE_MUTEX_W32 4812** <li> SQLITE_MUTEX_NOOP 4813** </ul>)^ 4814** 4815** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 4816** that does no real locking and is appropriate for use in 4817** a single-threaded application. ^The SQLITE_MUTEX_OS2, 4818** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations 4819** are appropriate for use on OS/2, Unix, and Windows. 4820** 4821** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 4822** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 4823** implementation is included with the library. In this case the 4824** application must supply a custom mutex implementation using the 4825** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 4826** before calling sqlite3_initialize() or any other public sqlite3_ 4827** function that calls sqlite3_initialize().)^ 4828** 4829** ^The sqlite3_mutex_alloc() routine allocates a new 4830** mutex and returns a pointer to it. ^If it returns NULL 4831** that means that a mutex could not be allocated. ^SQLite 4832** will unwind its stack and return an error. ^(The argument 4833** to sqlite3_mutex_alloc() is one of these integer constants: 4834** 4835** <ul> 4836** <li> SQLITE_MUTEX_FAST 4837** <li> SQLITE_MUTEX_RECURSIVE 4838** <li> SQLITE_MUTEX_STATIC_MASTER 4839** <li> SQLITE_MUTEX_STATIC_MEM 4840** <li> SQLITE_MUTEX_STATIC_MEM2 4841** <li> SQLITE_MUTEX_STATIC_PRNG 4842** <li> SQLITE_MUTEX_STATIC_LRU 4843** <li> SQLITE_MUTEX_STATIC_LRU2 4844** </ul>)^ 4845** 4846** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 4847** cause sqlite3_mutex_alloc() to create 4848** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 4849** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 4850** The mutex implementation does not need to make a distinction 4851** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 4852** not want to. ^SQLite will only request a recursive mutex in 4853** cases where it really needs one. ^If a faster non-recursive mutex 4854** implementation is available on the host platform, the mutex subsystem 4855** might return such a mutex in response to SQLITE_MUTEX_FAST. 4856** 4857** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 4858** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 4859** a pointer to a static preexisting mutex. ^Six static mutexes are 4860** used by the current version of SQLite. Future versions of SQLite 4861** may add additional static mutexes. Static mutexes are for internal 4862** use by SQLite only. Applications that use SQLite mutexes should 4863** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 4864** SQLITE_MUTEX_RECURSIVE. 4865** 4866** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 4867** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 4868** returns a different mutex on every call. ^But for the static 4869** mutex types, the same mutex is returned on every call that has 4870** the same type number. 4871** 4872** ^The sqlite3_mutex_free() routine deallocates a previously 4873** allocated dynamic mutex. ^SQLite is careful to deallocate every 4874** dynamic mutex that it allocates. The dynamic mutexes must not be in 4875** use when they are deallocated. Attempting to deallocate a static 4876** mutex results in undefined behavior. ^SQLite never deallocates 4877** a static mutex. 4878** 4879** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 4880** to enter a mutex. ^If another thread is already within the mutex, 4881** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 4882** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 4883** upon successful entry. ^(Mutexes created using 4884** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 4885** In such cases the, 4886** mutex must be exited an equal number of times before another thread 4887** can enter.)^ ^(If the same thread tries to enter any other 4888** kind of mutex more than once, the behavior is undefined. 4889** SQLite will never exhibit 4890** such behavior in its own use of mutexes.)^ 4891** 4892** ^(Some systems (for example, Windows 95) do not support the operation 4893** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 4894** will always return SQLITE_BUSY. The SQLite core only ever uses 4895** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 4896** 4897** ^The sqlite3_mutex_leave() routine exits a mutex that was 4898** previously entered by the same thread. ^(The behavior 4899** is undefined if the mutex is not currently entered by the 4900** calling thread or is not currently allocated. SQLite will 4901** never do either.)^ 4902** 4903** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 4904** sqlite3_mutex_leave() is a NULL pointer, then all three routines 4905** behave as no-ops. 4906** 4907** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 4908*/ 4909sqlite3_mutex *sqlite3_mutex_alloc(int); 4910void sqlite3_mutex_free(sqlite3_mutex*); 4911void sqlite3_mutex_enter(sqlite3_mutex*); 4912int sqlite3_mutex_try(sqlite3_mutex*); 4913void sqlite3_mutex_leave(sqlite3_mutex*); 4914 4915/* 4916** CAPI3REF: Mutex Methods Object 4917** 4918** An instance of this structure defines the low-level routines 4919** used to allocate and use mutexes. 4920** 4921** Usually, the default mutex implementations provided by SQLite are 4922** sufficient, however the user has the option of substituting a custom 4923** implementation for specialized deployments or systems for which SQLite 4924** does not provide a suitable implementation. In this case, the user 4925** creates and populates an instance of this structure to pass 4926** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 4927** Additionally, an instance of this structure can be used as an 4928** output variable when querying the system for the current mutex 4929** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 4930** 4931** ^The xMutexInit method defined by this structure is invoked as 4932** part of system initialization by the sqlite3_initialize() function. 4933** ^The xMutexInit routine is calle by SQLite exactly once for each 4934** effective call to [sqlite3_initialize()]. 4935** 4936** ^The xMutexEnd method defined by this structure is invoked as 4937** part of system shutdown by the sqlite3_shutdown() function. The 4938** implementation of this method is expected to release all outstanding 4939** resources obtained by the mutex methods implementation, especially 4940** those obtained by the xMutexInit method. ^The xMutexEnd() 4941** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 4942** 4943** ^(The remaining seven methods defined by this structure (xMutexAlloc, 4944** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 4945** xMutexNotheld) implement the following interfaces (respectively): 4946** 4947** <ul> 4948** <li> [sqlite3_mutex_alloc()] </li> 4949** <li> [sqlite3_mutex_free()] </li> 4950** <li> [sqlite3_mutex_enter()] </li> 4951** <li> [sqlite3_mutex_try()] </li> 4952** <li> [sqlite3_mutex_leave()] </li> 4953** <li> [sqlite3_mutex_held()] </li> 4954** <li> [sqlite3_mutex_notheld()] </li> 4955** </ul>)^ 4956** 4957** The only difference is that the public sqlite3_XXX functions enumerated 4958** above silently ignore any invocations that pass a NULL pointer instead 4959** of a valid mutex handle. The implementations of the methods defined 4960** by this structure are not required to handle this case, the results 4961** of passing a NULL pointer instead of a valid mutex handle are undefined 4962** (i.e. it is acceptable to provide an implementation that segfaults if 4963** it is passed a NULL pointer). 4964** 4965** The xMutexInit() method must be threadsafe. ^It must be harmless to 4966** invoke xMutexInit() multiple times within the same process and without 4967** intervening calls to xMutexEnd(). Second and subsequent calls to 4968** xMutexInit() must be no-ops. 4969** 4970** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 4971** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 4972** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 4973** memory allocation for a fast or recursive mutex. 4974** 4975** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 4976** called, but only if the prior call to xMutexInit returned SQLITE_OK. 4977** If xMutexInit fails in any way, it is expected to clean up after itself 4978** prior to returning. 4979*/ 4980typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 4981struct sqlite3_mutex_methods { 4982 int (*xMutexInit)(void); 4983 int (*xMutexEnd)(void); 4984 sqlite3_mutex *(*xMutexAlloc)(int); 4985 void (*xMutexFree)(sqlite3_mutex *); 4986 void (*xMutexEnter)(sqlite3_mutex *); 4987 int (*xMutexTry)(sqlite3_mutex *); 4988 void (*xMutexLeave)(sqlite3_mutex *); 4989 int (*xMutexHeld)(sqlite3_mutex *); 4990 int (*xMutexNotheld)(sqlite3_mutex *); 4991}; 4992 4993/* 4994** CAPI3REF: Mutex Verification Routines 4995** 4996** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 4997** are intended for use inside assert() statements. ^The SQLite core 4998** never uses these routines except inside an assert() and applications 4999** are advised to follow the lead of the core. ^The SQLite core only 5000** provides implementations for these routines when it is compiled 5001** with the SQLITE_DEBUG flag. ^External mutex implementations 5002** are only required to provide these routines if SQLITE_DEBUG is 5003** defined and if NDEBUG is not defined. 5004** 5005** ^These routines should return true if the mutex in their argument 5006** is held or not held, respectively, by the calling thread. 5007** 5008** ^The implementation is not required to provided versions of these 5009** routines that actually work. If the implementation does not provide working 5010** versions of these routines, it should at least provide stubs that always 5011** return true so that one does not get spurious assertion failures. 5012** 5013** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 5014** the routine should return 1. This seems counter-intuitive since 5015** clearly the mutex cannot be held if it does not exist. But the 5016** the reason the mutex does not exist is because the build is not 5017** using mutexes. And we do not want the assert() containing the 5018** call to sqlite3_mutex_held() to fail, so a non-zero return is 5019** the appropriate thing to do. ^The sqlite3_mutex_notheld() 5020** interface should also return 1 when given a NULL pointer. 5021*/ 5022#ifndef NDEBUG 5023int sqlite3_mutex_held(sqlite3_mutex*); 5024int sqlite3_mutex_notheld(sqlite3_mutex*); 5025#endif 5026 5027/* 5028** CAPI3REF: Mutex Types 5029** 5030** The [sqlite3_mutex_alloc()] interface takes a single argument 5031** which is one of these integer constants. 5032** 5033** The set of static mutexes may change from one SQLite release to the 5034** next. Applications that override the built-in mutex logic must be 5035** prepared to accommodate additional static mutexes. 5036*/ 5037#define SQLITE_MUTEX_FAST 0 5038#define SQLITE_MUTEX_RECURSIVE 1 5039#define SQLITE_MUTEX_STATIC_MASTER 2 5040#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 5041#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 5042#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 5043#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 5044#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 5045#define SQLITE_MUTEX_STATIC_LRU2 7 /* lru page list */ 5046 5047/* 5048** CAPI3REF: Retrieve the mutex for a database connection 5049** 5050** ^This interface returns a pointer the [sqlite3_mutex] object that 5051** serializes access to the [database connection] given in the argument 5052** when the [threading mode] is Serialized. 5053** ^If the [threading mode] is Single-thread or Multi-thread then this 5054** routine returns a NULL pointer. 5055*/ 5056sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 5057 5058/* 5059** CAPI3REF: Low-Level Control Of Database Files 5060** 5061** ^The [sqlite3_file_control()] interface makes a direct call to the 5062** xFileControl method for the [sqlite3_io_methods] object associated 5063** with a particular database identified by the second argument. ^The 5064** name of the database "main" for the main database or "temp" for the 5065** TEMP database, or the name that appears after the AS keyword for 5066** databases that are added using the [ATTACH] SQL command. 5067** ^A NULL pointer can be used in place of "main" to refer to the 5068** main database file. 5069** ^The third and fourth parameters to this routine 5070** are passed directly through to the second and third parameters of 5071** the xFileControl method. ^The return value of the xFileControl 5072** method becomes the return value of this routine. 5073** 5074** ^If the second parameter (zDbName) does not match the name of any 5075** open database file, then SQLITE_ERROR is returned. ^This error 5076** code is not remembered and will not be recalled by [sqlite3_errcode()] 5077** or [sqlite3_errmsg()]. The underlying xFileControl method might 5078** also return SQLITE_ERROR. There is no way to distinguish between 5079** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5080** xFileControl method. 5081** 5082** See also: [SQLITE_FCNTL_LOCKSTATE] 5083*/ 5084int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5085 5086/* 5087** CAPI3REF: Testing Interface 5088** 5089** ^The sqlite3_test_control() interface is used to read out internal 5090** state of SQLite and to inject faults into SQLite for testing 5091** purposes. ^The first parameter is an operation code that determines 5092** the number, meaning, and operation of all subsequent parameters. 5093** 5094** This interface is not for use by applications. It exists solely 5095** for verifying the correct operation of the SQLite library. Depending 5096** on how the SQLite library is compiled, this interface might not exist. 5097** 5098** The details of the operation codes, their meanings, the parameters 5099** they take, and what they do are all subject to change without notice. 5100** Unlike most of the SQLite API, this function is not guaranteed to 5101** operate consistently from one release to the next. 5102*/ 5103int sqlite3_test_control(int op, ...); 5104 5105/* 5106** CAPI3REF: Testing Interface Operation Codes 5107** 5108** These constants are the valid operation code parameters used 5109** as the first argument to [sqlite3_test_control()]. 5110** 5111** These parameters and their meanings are subject to change 5112** without notice. These values are for testing purposes only. 5113** Applications should not use any of these parameters or the 5114** [sqlite3_test_control()] interface. 5115*/ 5116#define SQLITE_TESTCTRL_FIRST 5 5117#define SQLITE_TESTCTRL_PRNG_SAVE 5 5118#define SQLITE_TESTCTRL_PRNG_RESTORE 6 5119#define SQLITE_TESTCTRL_PRNG_RESET 7 5120#define SQLITE_TESTCTRL_BITVEC_TEST 8 5121#define SQLITE_TESTCTRL_FAULT_INSTALL 9 5122#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5123#define SQLITE_TESTCTRL_PENDING_BYTE 11 5124#define SQLITE_TESTCTRL_ASSERT 12 5125#define SQLITE_TESTCTRL_ALWAYS 13 5126#define SQLITE_TESTCTRL_RESERVE 14 5127#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 5128#define SQLITE_TESTCTRL_ISKEYWORD 16 5129#define SQLITE_TESTCTRL_PGHDRSZ 17 5130#define SQLITE_TESTCTRL_SCRATCHMALLOC 18 5131#define SQLITE_TESTCTRL_LAST 18 5132 5133/* 5134** CAPI3REF: SQLite Runtime Status 5135** 5136** ^This interface is used to retrieve runtime status information 5137** about the performance of SQLite, and optionally to reset various 5138** highwater marks. ^The first argument is an integer code for 5139** the specific parameter to measure. ^(Recognized integer codes 5140** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].)^ 5141** ^The current value of the parameter is returned into *pCurrent. 5142** ^The highest recorded value is returned in *pHighwater. ^If the 5143** resetFlag is true, then the highest record value is reset after 5144** *pHighwater is written. ^(Some parameters do not record the highest 5145** value. For those parameters 5146** nothing is written into *pHighwater and the resetFlag is ignored.)^ 5147** ^(Other parameters record only the highwater mark and not the current 5148** value. For these latter parameters nothing is written into *pCurrent.)^ 5149** 5150** ^The sqlite3_status() routine returns SQLITE_OK on success and a 5151** non-zero [error code] on failure. 5152** 5153** This routine is threadsafe but is not atomic. This routine can be 5154** called while other threads are running the same or different SQLite 5155** interfaces. However the values returned in *pCurrent and 5156** *pHighwater reflect the status of SQLite at different points in time 5157** and it is possible that another thread might change the parameter 5158** in between the times when *pCurrent and *pHighwater are written. 5159** 5160** See also: [sqlite3_db_status()] 5161*/ 5162int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 5163 5164 5165/* 5166** CAPI3REF: Status Parameters 5167** 5168** These integer constants designate various run-time status parameters 5169** that can be returned by [sqlite3_status()]. 5170** 5171** <dl> 5172** ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 5173** <dd>This parameter is the current amount of memory checked out 5174** using [sqlite3_malloc()], either directly or indirectly. The 5175** figure includes calls made to [sqlite3_malloc()] by the application 5176** and internal memory usage by the SQLite library. Scratch memory 5177** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 5178** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 5179** this parameter. The amount returned is the sum of the allocation 5180** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 5181** 5182** ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 5183** <dd>This parameter records the largest memory allocation request 5184** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 5185** internal equivalents). Only the value returned in the 5186** *pHighwater parameter to [sqlite3_status()] is of interest. 5187** The value written into the *pCurrent parameter is undefined.</dd>)^ 5188** 5189** ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 5190** <dd>This parameter records the number of separate memory allocations.</dd>)^ 5191** 5192** ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 5193** <dd>This parameter returns the number of pages used out of the 5194** [pagecache memory allocator] that was configured using 5195** [SQLITE_CONFIG_PAGECACHE]. The 5196** value returned is in pages, not in bytes.</dd>)^ 5197** 5198** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5199** <dd>This parameter returns the number of bytes of page cache 5200** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 5201** buffer and where forced to overflow to [sqlite3_malloc()]. The 5202** returned value includes allocations that overflowed because they 5203** where too large (they were larger than the "sz" parameter to 5204** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 5205** no space was left in the page cache.</dd>)^ 5206** 5207** ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 5208** <dd>This parameter records the largest memory allocation request 5209** handed to [pagecache memory allocator]. Only the value returned in the 5210** *pHighwater parameter to [sqlite3_status()] is of interest. 5211** The value written into the *pCurrent parameter is undefined.</dd>)^ 5212** 5213** ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 5214** <dd>This parameter returns the number of allocations used out of the 5215** [scratch memory allocator] configured using 5216** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5217** in bytes. Since a single thread may only have one scratch allocation 5218** outstanding at time, this parameter also reports the number of threads 5219** using scratch memory at the same time.</dd>)^ 5220** 5221** ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5222** <dd>This parameter returns the number of bytes of scratch memory 5223** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 5224** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5225** returned include overflows because the requested allocation was too 5226** larger (that is, because the requested allocation was larger than the 5227** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5228** slots were available. 5229** </dd>)^ 5230** 5231** ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5232** <dd>This parameter records the largest memory allocation request 5233** handed to [scratch memory allocator]. Only the value returned in the 5234** *pHighwater parameter to [sqlite3_status()] is of interest. 5235** The value written into the *pCurrent parameter is undefined.</dd>)^ 5236** 5237** ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 5238** <dd>This parameter records the deepest parser stack. It is only 5239** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 5240** </dl> 5241** 5242** New status parameters may be added from time to time. 5243*/ 5244#define SQLITE_STATUS_MEMORY_USED 0 5245#define SQLITE_STATUS_PAGECACHE_USED 1 5246#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5247#define SQLITE_STATUS_SCRATCH_USED 3 5248#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5249#define SQLITE_STATUS_MALLOC_SIZE 5 5250#define SQLITE_STATUS_PARSER_STACK 6 5251#define SQLITE_STATUS_PAGECACHE_SIZE 7 5252#define SQLITE_STATUS_SCRATCH_SIZE 8 5253#define SQLITE_STATUS_MALLOC_COUNT 9 5254 5255/* 5256** CAPI3REF: Database Connection Status 5257** 5258** ^This interface is used to retrieve runtime status information 5259** about a single [database connection]. ^The first argument is the 5260** database connection object to be interrogated. ^The second argument 5261** is an integer constant, taken from the set of 5262** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros, that 5263** determines the parameter to interrogate. The set of 5264** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros is likely 5265** to grow in future releases of SQLite. 5266** 5267** ^The current value of the requested parameter is written into *pCur 5268** and the highest instantaneous value is written into *pHiwtr. ^If 5269** the resetFlg is true, then the highest instantaneous value is 5270** reset back down to the current value. 5271** 5272** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 5273** non-zero [error code] on failure. 5274** 5275** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5276*/ 5277int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5278 5279/* 5280** CAPI3REF: Status Parameters for database connections 5281** 5282** These constants are the available integer "verbs" that can be passed as 5283** the second argument to the [sqlite3_db_status()] interface. 5284** 5285** New verbs may be added in future releases of SQLite. Existing verbs 5286** might be discontinued. Applications should check the return code from 5287** [sqlite3_db_status()] to make sure that the call worked. 5288** The [sqlite3_db_status()] interface will return a non-zero error code 5289** if a discontinued or unsupported verb is invoked. 5290** 5291** <dl> 5292** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5293** <dd>This parameter returns the number of lookaside memory slots currently 5294** checked out.</dd>)^ 5295** 5296** ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 5297** <dd>This parameter returns the approximate number of of bytes of heap 5298** memory used by all pager caches associated with the database connection.)^ 5299** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 5300** 5301** ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 5302** <dd>This parameter returns the approximate number of of bytes of heap 5303** memory used to store the schema for all databases associated 5304** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 5305** ^The full amount of memory used by the schemas is reported, even if the 5306** schema memory is shared with other database connections due to 5307** [shared cache mode] being enabled. 5308** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 5309** 5310** ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 5311** <dd>This parameter returns the approximate number of of bytes of heap 5312** and lookaside memory used by all prepared statements associated with 5313** the database connection.)^ 5314** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 5315** </dd> 5316** </dl> 5317*/ 5318#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 5319#define SQLITE_DBSTATUS_CACHE_USED 1 5320#define SQLITE_DBSTATUS_SCHEMA_USED 2 5321#define SQLITE_DBSTATUS_STMT_USED 3 5322#define SQLITE_DBSTATUS_MAX 3 /* Largest defined DBSTATUS */ 5323 5324 5325/* 5326** CAPI3REF: Prepared Statement Status 5327** 5328** ^(Each prepared statement maintains various 5329** [SQLITE_STMTSTATUS_SORT | counters] that measure the number 5330** of times it has performed specific operations.)^ These counters can 5331** be used to monitor the performance characteristics of the prepared 5332** statements. For example, if the number of table steps greatly exceeds 5333** the number of table searches or result rows, that would tend to indicate 5334** that the prepared statement is using a full table scan rather than 5335** an index. 5336** 5337** ^(This interface is used to retrieve and reset counter values from 5338** a [prepared statement]. The first argument is the prepared statement 5339** object to be interrogated. The second argument 5340** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter] 5341** to be interrogated.)^ 5342** ^The current value of the requested counter is returned. 5343** ^If the resetFlg is true, then the counter is reset to zero after this 5344** interface call returns. 5345** 5346** See also: [sqlite3_status()] and [sqlite3_db_status()]. 5347*/ 5348int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 5349 5350/* 5351** CAPI3REF: Status Parameters for prepared statements 5352** 5353** These preprocessor macros define integer codes that name counter 5354** values associated with the [sqlite3_stmt_status()] interface. 5355** The meanings of the various counters are as follows: 5356** 5357** <dl> 5358** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 5359** <dd>^This is the number of times that SQLite has stepped forward in 5360** a table as part of a full table scan. Large numbers for this counter 5361** may indicate opportunities for performance improvement through 5362** careful use of indices.</dd> 5363** 5364** <dt>SQLITE_STMTSTATUS_SORT</dt> 5365** <dd>^This is the number of sort operations that have occurred. 5366** A non-zero value in this counter may indicate an opportunity to 5367** improvement performance through careful use of indices.</dd> 5368** 5369** <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 5370** <dd>^This is the number of rows inserted into transient indices that 5371** were created automatically in order to help joins run faster. 5372** A non-zero value in this counter may indicate an opportunity to 5373** improvement performance by adding permanent indices that do not 5374** need to be reinitialized each time the statement is run.</dd> 5375** 5376** </dl> 5377*/ 5378#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 5379#define SQLITE_STMTSTATUS_SORT 2 5380#define SQLITE_STMTSTATUS_AUTOINDEX 3 5381 5382/* 5383** CAPI3REF: Custom Page Cache Object 5384** 5385** The sqlite3_pcache type is opaque. It is implemented by 5386** the pluggable module. The SQLite core has no knowledge of 5387** its size or internal structure and never deals with the 5388** sqlite3_pcache object except by holding and passing pointers 5389** to the object. 5390** 5391** See [sqlite3_pcache_methods] for additional information. 5392*/ 5393typedef struct sqlite3_pcache sqlite3_pcache; 5394 5395/* 5396** CAPI3REF: Application Defined Page Cache. 5397** KEYWORDS: {page cache} 5398** 5399** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can 5400** register an alternative page cache implementation by passing in an 5401** instance of the sqlite3_pcache_methods structure.)^ The majority of the 5402** heap memory used by SQLite is used by the page cache to cache data read 5403** from, or ready to be written to, the database file. By implementing a 5404** custom page cache using this API, an application can control more 5405** precisely the amount of memory consumed by SQLite, the way in which 5406** that memory is allocated and released, and the policies used to 5407** determine exactly which parts of a database file are cached and for 5408** how long. 5409** 5410** ^(The contents of the sqlite3_pcache_methods structure are copied to an 5411** internal buffer by SQLite within the call to [sqlite3_config]. Hence 5412** the application may discard the parameter after the call to 5413** [sqlite3_config()] returns.)^ 5414** 5415** ^The xInit() method is called once for each call to [sqlite3_initialize()] 5416** (usually only once during the lifetime of the process). ^(The xInit() 5417** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^ 5418** ^The xInit() method can set up up global structures and/or any mutexes 5419** required by the custom page cache implementation. 5420** 5421** ^The xShutdown() method is called from within [sqlite3_shutdown()], 5422** if the application invokes this API. It can be used to clean up 5423** any outstanding resources before process shutdown, if required. 5424** 5425** ^SQLite holds a [SQLITE_MUTEX_RECURSIVE] mutex when it invokes 5426** the xInit method, so the xInit method need not be threadsafe. ^The 5427** xShutdown method is only called from [sqlite3_shutdown()] so it does 5428** not need to be threadsafe either. All other methods must be threadsafe 5429** in multithreaded applications. 5430** 5431** ^SQLite will never invoke xInit() more than once without an intervening 5432** call to xShutdown(). 5433** 5434** ^The xCreate() method is used to construct a new cache instance. SQLite 5435** will typically create one cache instance for each open database file, 5436** though this is not guaranteed. ^The 5437** first parameter, szPage, is the size in bytes of the pages that must 5438** be allocated by the cache. ^szPage will not be a power of two. ^szPage 5439** will the page size of the database file that is to be cached plus an 5440** increment (here called "R") of about 100 or 200. ^SQLite will use the 5441** extra R bytes on each page to store metadata about the underlying 5442** database page on disk. The value of R depends 5443** on the SQLite version, the target platform, and how SQLite was compiled. 5444** ^R is constant for a particular build of SQLite. ^The second argument to 5445** xCreate(), bPurgeable, is true if the cache being created will 5446** be used to cache database pages of a file stored on disk, or 5447** false if it is used for an in-memory database. ^The cache implementation 5448** does not have to do anything special based with the value of bPurgeable; 5449** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 5450** never invoke xUnpin() except to deliberately delete a page. 5451** ^In other words, a cache created with bPurgeable set to false will 5452** never contain any unpinned pages. 5453** 5454** ^(The xCachesize() method may be called at any time by SQLite to set the 5455** suggested maximum cache-size (number of pages stored by) the cache 5456** instance passed as the first argument. This is the value configured using 5457** the SQLite "[PRAGMA cache_size]" command.)^ ^As with the bPurgeable 5458** parameter, the implementation is not required to do anything with this 5459** value; it is advisory only. 5460** 5461** ^The xPagecount() method should return the number of pages currently 5462** stored in the cache. 5463** 5464** ^The xFetch() method is used to fetch a page and return a pointer to it. 5465** ^A 'page', in this context, is a buffer of szPage bytes aligned at an 5466** 8-byte boundary. ^The page to be fetched is determined by the key. ^The 5467** mimimum key value is 1. After it has been retrieved using xFetch, the page 5468** is considered to be "pinned". 5469** 5470** ^If the requested page is already in the page cache, then the page cache 5471** implementation must return a pointer to the page buffer with its content 5472** intact. ^(If the requested page is not already in the cache, then the 5473** behavior of the cache implementation is determined by the value of the 5474** createFlag parameter passed to xFetch, according to the following table: 5475** 5476** <table border=1 width=85% align=center> 5477** <tr><th> createFlag <th> Behaviour when page is not already in cache 5478** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 5479** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 5480** Otherwise return NULL. 5481** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 5482** NULL if allocating a new page is effectively impossible. 5483** </table>)^ 5484** 5485** SQLite will normally invoke xFetch() with a createFlag of 0 or 1. If 5486** a call to xFetch() with createFlag==1 returns NULL, then SQLite will 5487** attempt to unpin one or more cache pages by spilling the content of 5488** pinned pages to disk and synching the operating system disk cache. After 5489** attempting to unpin pages, the xFetch() method will be invoked again with 5490** a createFlag of 2. 5491** 5492** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 5493** as its second argument. ^(If the third parameter, discard, is non-zero, 5494** then the page should be evicted from the cache. In this case SQLite 5495** assumes that the next time the page is retrieved from the cache using 5496** the xFetch() method, it will be zeroed.)^ ^If the discard parameter is 5497** zero, then the page is considered to be unpinned. ^The cache implementation 5498** may choose to evict unpinned pages at any time. 5499** 5500** ^(The cache is not required to perform any reference counting. A single 5501** call to xUnpin() unpins the page regardless of the number of prior calls 5502** to xFetch().)^ 5503** 5504** ^The xRekey() method is used to change the key value associated with the 5505** page passed as the second argument from oldKey to newKey. ^If the cache 5506** previously contains an entry associated with newKey, it should be 5507** discarded. ^Any prior cache entry associated with newKey is guaranteed not 5508** to be pinned. 5509** 5510** ^When SQLite calls the xTruncate() method, the cache must discard all 5511** existing cache entries with page numbers (keys) greater than or equal 5512** to the value of the iLimit parameter passed to xTruncate(). ^If any 5513** of these pages are pinned, they are implicitly unpinned, meaning that 5514** they can be safely discarded. 5515** 5516** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 5517** All resources associated with the specified cache should be freed. ^After 5518** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 5519** handle invalid, and will not use it with any other sqlite3_pcache_methods 5520** functions. 5521*/ 5522typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 5523struct sqlite3_pcache_methods { 5524 void *pArg; 5525 int (*xInit)(void*); 5526 void (*xShutdown)(void*); 5527 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 5528 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 5529 int (*xPagecount)(sqlite3_pcache*); 5530 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 5531 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 5532 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 5533 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 5534 void (*xDestroy)(sqlite3_pcache*); 5535}; 5536 5537/* 5538** CAPI3REF: Online Backup Object 5539** 5540** The sqlite3_backup object records state information about an ongoing 5541** online backup operation. ^The sqlite3_backup object is created by 5542** a call to [sqlite3_backup_init()] and is destroyed by a call to 5543** [sqlite3_backup_finish()]. 5544** 5545** See Also: [Using the SQLite Online Backup API] 5546*/ 5547typedef struct sqlite3_backup sqlite3_backup; 5548 5549/* 5550** CAPI3REF: Online Backup API. 5551** 5552** The backup API copies the content of one database into another. 5553** It is useful either for creating backups of databases or 5554** for copying in-memory databases to or from persistent files. 5555** 5556** See Also: [Using the SQLite Online Backup API] 5557** 5558** ^Exclusive access is required to the destination database for the 5559** duration of the operation. ^However the source database is only 5560** read-locked while it is actually being read; it is not locked 5561** continuously for the entire backup operation. ^Thus, the backup may be 5562** performed on a live source database without preventing other users from 5563** reading or writing to the source database while the backup is underway. 5564** 5565** ^(To perform a backup operation: 5566** <ol> 5567** <li><b>sqlite3_backup_init()</b> is called once to initialize the 5568** backup, 5569** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 5570** the data between the two databases, and finally 5571** <li><b>sqlite3_backup_finish()</b> is called to release all resources 5572** associated with the backup operation. 5573** </ol>)^ 5574** There should be exactly one call to sqlite3_backup_finish() for each 5575** successful call to sqlite3_backup_init(). 5576** 5577** <b>sqlite3_backup_init()</b> 5578** 5579** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 5580** [database connection] associated with the destination database 5581** and the database name, respectively. 5582** ^The database name is "main" for the main database, "temp" for the 5583** temporary database, or the name specified after the AS keyword in 5584** an [ATTACH] statement for an attached database. 5585** ^The S and M arguments passed to 5586** sqlite3_backup_init(D,N,S,M) identify the [database connection] 5587** and database name of the source database, respectively. 5588** ^The source and destination [database connections] (parameters S and D) 5589** must be different or else sqlite3_backup_init(D,N,S,M) will file with 5590** an error. 5591** 5592** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 5593** returned and an error code and error message are store3d in the 5594** destination [database connection] D. 5595** ^The error code and message for the failed call to sqlite3_backup_init() 5596** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 5597** [sqlite3_errmsg16()] functions. 5598** ^A successful call to sqlite3_backup_init() returns a pointer to an 5599** [sqlite3_backup] object. 5600** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 5601** sqlite3_backup_finish() functions to perform the specified backup 5602** operation. 5603** 5604** <b>sqlite3_backup_step()</b> 5605** 5606** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 5607** the source and destination databases specified by [sqlite3_backup] object B. 5608** ^If N is negative, all remaining source pages are copied. 5609** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 5610** are still more pages to be copied, then the function resturns [SQLITE_OK]. 5611** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 5612** from source to destination, then it returns [SQLITE_DONE]. 5613** ^If an error occurs while running sqlite3_backup_step(B,N), 5614** then an [error code] is returned. ^As well as [SQLITE_OK] and 5615** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 5616** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 5617** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 5618** 5619** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 5620** <ol> 5621** <li> the destination database was opened read-only, or 5622** <li> the destination database is using write-ahead-log journaling 5623** and the destination and source page sizes differ, or 5624** <li> The destination database is an in-memory database and the 5625** destination and source page sizes differ. 5626** </ol>)^ 5627** 5628** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 5629** the [sqlite3_busy_handler | busy-handler function] 5630** is invoked (if one is specified). ^If the 5631** busy-handler returns non-zero before the lock is available, then 5632** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 5633** sqlite3_backup_step() can be retried later. ^If the source 5634** [database connection] 5635** is being used to write to the source database when sqlite3_backup_step() 5636** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 5637** case the call to sqlite3_backup_step() can be retried later on. ^(If 5638** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 5639** [SQLITE_READONLY] is returned, then 5640** there is no point in retrying the call to sqlite3_backup_step(). These 5641** errors are considered fatal.)^ The application must accept 5642** that the backup operation has failed and pass the backup operation handle 5643** to the sqlite3_backup_finish() to release associated resources. 5644** 5645** ^The first call to sqlite3_backup_step() obtains an exclusive lock 5646** on the destination file. ^The exclusive lock is not released until either 5647** sqlite3_backup_finish() is called or the backup operation is complete 5648** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 5649** sqlite3_backup_step() obtains a [shared lock] on the source database that 5650** lasts for the duration of the sqlite3_backup_step() call. 5651** ^Because the source database is not locked between calls to 5652** sqlite3_backup_step(), the source database may be modified mid-way 5653** through the backup process. ^If the source database is modified by an 5654** external process or via a database connection other than the one being 5655** used by the backup operation, then the backup will be automatically 5656** restarted by the next call to sqlite3_backup_step(). ^If the source 5657** database is modified by the using the same database connection as is used 5658** by the backup operation, then the backup database is automatically 5659** updated at the same time. 5660** 5661** <b>sqlite3_backup_finish()</b> 5662** 5663** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 5664** application wishes to abandon the backup operation, the application 5665** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 5666** ^The sqlite3_backup_finish() interfaces releases all 5667** resources associated with the [sqlite3_backup] object. 5668** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 5669** active write-transaction on the destination database is rolled back. 5670** The [sqlite3_backup] object is invalid 5671** and may not be used following a call to sqlite3_backup_finish(). 5672** 5673** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 5674** sqlite3_backup_step() errors occurred, regardless or whether or not 5675** sqlite3_backup_step() completed. 5676** ^If an out-of-memory condition or IO error occurred during any prior 5677** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 5678** sqlite3_backup_finish() returns the corresponding [error code]. 5679** 5680** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 5681** is not a permanent error and does not affect the return value of 5682** sqlite3_backup_finish(). 5683** 5684** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b> 5685** 5686** ^Each call to sqlite3_backup_step() sets two values inside 5687** the [sqlite3_backup] object: the number of pages still to be backed 5688** up and the total number of pages in the source database file. 5689** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 5690** retrieve these two values, respectively. 5691** 5692** ^The values returned by these functions are only updated by 5693** sqlite3_backup_step(). ^If the source database is modified during a backup 5694** operation, then the values are not updated to account for any extra 5695** pages that need to be updated or the size of the source database file 5696** changing. 5697** 5698** <b>Concurrent Usage of Database Handles</b> 5699** 5700** ^The source [database connection] may be used by the application for other 5701** purposes while a backup operation is underway or being initialized. 5702** ^If SQLite is compiled and configured to support threadsafe database 5703** connections, then the source database connection may be used concurrently 5704** from within other threads. 5705** 5706** However, the application must guarantee that the destination 5707** [database connection] is not passed to any other API (by any thread) after 5708** sqlite3_backup_init() is called and before the corresponding call to 5709** sqlite3_backup_finish(). SQLite does not currently check to see 5710** if the application incorrectly accesses the destination [database connection] 5711** and so no error code is reported, but the operations may malfunction 5712** nevertheless. Use of the destination database connection while a 5713** backup is in progress might also also cause a mutex deadlock. 5714** 5715** If running in [shared cache mode], the application must 5716** guarantee that the shared cache used by the destination database 5717** is not accessed while the backup is running. In practice this means 5718** that the application must guarantee that the disk file being 5719** backed up to is not accessed by any connection within the process, 5720** not just the specific connection that was passed to sqlite3_backup_init(). 5721** 5722** The [sqlite3_backup] object itself is partially threadsafe. Multiple 5723** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 5724** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 5725** APIs are not strictly speaking threadsafe. If they are invoked at the 5726** same time as another thread is invoking sqlite3_backup_step() it is 5727** possible that they return invalid values. 5728*/ 5729sqlite3_backup *sqlite3_backup_init( 5730 sqlite3 *pDest, /* Destination database handle */ 5731 const char *zDestName, /* Destination database name */ 5732 sqlite3 *pSource, /* Source database handle */ 5733 const char *zSourceName /* Source database name */ 5734); 5735int sqlite3_backup_step(sqlite3_backup *p, int nPage); 5736int sqlite3_backup_finish(sqlite3_backup *p); 5737int sqlite3_backup_remaining(sqlite3_backup *p); 5738int sqlite3_backup_pagecount(sqlite3_backup *p); 5739 5740/* 5741** CAPI3REF: Unlock Notification 5742** 5743** ^When running in shared-cache mode, a database operation may fail with 5744** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 5745** individual tables within the shared-cache cannot be obtained. See 5746** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 5747** ^This API may be used to register a callback that SQLite will invoke 5748** when the connection currently holding the required lock relinquishes it. 5749** ^This API is only available if the library was compiled with the 5750** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 5751** 5752** See Also: [Using the SQLite Unlock Notification Feature]. 5753** 5754** ^Shared-cache locks are released when a database connection concludes 5755** its current transaction, either by committing it or rolling it back. 5756** 5757** ^When a connection (known as the blocked connection) fails to obtain a 5758** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 5759** identity of the database connection (the blocking connection) that 5760** has locked the required resource is stored internally. ^After an 5761** application receives an SQLITE_LOCKED error, it may call the 5762** sqlite3_unlock_notify() method with the blocked connection handle as 5763** the first argument to register for a callback that will be invoked 5764** when the blocking connections current transaction is concluded. ^The 5765** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 5766** call that concludes the blocking connections transaction. 5767** 5768** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 5769** there is a chance that the blocking connection will have already 5770** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 5771** If this happens, then the specified callback is invoked immediately, 5772** from within the call to sqlite3_unlock_notify().)^ 5773** 5774** ^If the blocked connection is attempting to obtain a write-lock on a 5775** shared-cache table, and more than one other connection currently holds 5776** a read-lock on the same table, then SQLite arbitrarily selects one of 5777** the other connections to use as the blocking connection. 5778** 5779** ^(There may be at most one unlock-notify callback registered by a 5780** blocked connection. If sqlite3_unlock_notify() is called when the 5781** blocked connection already has a registered unlock-notify callback, 5782** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 5783** called with a NULL pointer as its second argument, then any existing 5784** unlock-notify callback is canceled. ^The blocked connections 5785** unlock-notify callback may also be canceled by closing the blocked 5786** connection using [sqlite3_close()]. 5787** 5788** The unlock-notify callback is not reentrant. If an application invokes 5789** any sqlite3_xxx API functions from within an unlock-notify callback, a 5790** crash or deadlock may be the result. 5791** 5792** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 5793** returns SQLITE_OK. 5794** 5795** <b>Callback Invocation Details</b> 5796** 5797** When an unlock-notify callback is registered, the application provides a 5798** single void* pointer that is passed to the callback when it is invoked. 5799** However, the signature of the callback function allows SQLite to pass 5800** it an array of void* context pointers. The first argument passed to 5801** an unlock-notify callback is a pointer to an array of void* pointers, 5802** and the second is the number of entries in the array. 5803** 5804** When a blocking connections transaction is concluded, there may be 5805** more than one blocked connection that has registered for an unlock-notify 5806** callback. ^If two or more such blocked connections have specified the 5807** same callback function, then instead of invoking the callback function 5808** multiple times, it is invoked once with the set of void* context pointers 5809** specified by the blocked connections bundled together into an array. 5810** This gives the application an opportunity to prioritize any actions 5811** related to the set of unblocked database connections. 5812** 5813** <b>Deadlock Detection</b> 5814** 5815** Assuming that after registering for an unlock-notify callback a 5816** database waits for the callback to be issued before taking any further 5817** action (a reasonable assumption), then using this API may cause the 5818** application to deadlock. For example, if connection X is waiting for 5819** connection Y's transaction to be concluded, and similarly connection 5820** Y is waiting on connection X's transaction, then neither connection 5821** will proceed and the system may remain deadlocked indefinitely. 5822** 5823** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 5824** detection. ^If a given call to sqlite3_unlock_notify() would put the 5825** system in a deadlocked state, then SQLITE_LOCKED is returned and no 5826** unlock-notify callback is registered. The system is said to be in 5827** a deadlocked state if connection A has registered for an unlock-notify 5828** callback on the conclusion of connection B's transaction, and connection 5829** B has itself registered for an unlock-notify callback when connection 5830** A's transaction is concluded. ^Indirect deadlock is also detected, so 5831** the system is also considered to be deadlocked if connection B has 5832** registered for an unlock-notify callback on the conclusion of connection 5833** C's transaction, where connection C is waiting on connection A. ^Any 5834** number of levels of indirection are allowed. 5835** 5836** <b>The "DROP TABLE" Exception</b> 5837** 5838** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 5839** always appropriate to call sqlite3_unlock_notify(). There is however, 5840** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 5841** SQLite checks if there are any currently executing SELECT statements 5842** that belong to the same connection. If there are, SQLITE_LOCKED is 5843** returned. In this case there is no "blocking connection", so invoking 5844** sqlite3_unlock_notify() results in the unlock-notify callback being 5845** invoked immediately. If the application then re-attempts the "DROP TABLE" 5846** or "DROP INDEX" query, an infinite loop might be the result. 5847** 5848** One way around this problem is to check the extended error code returned 5849** by an sqlite3_step() call. ^(If there is a blocking connection, then the 5850** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 5851** the special "DROP TABLE/INDEX" case, the extended error code is just 5852** SQLITE_LOCKED.)^ 5853*/ 5854int sqlite3_unlock_notify( 5855 sqlite3 *pBlocked, /* Waiting connection */ 5856 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 5857 void *pNotifyArg /* Argument to pass to xNotify */ 5858); 5859 5860 5861/* 5862** CAPI3REF: String Comparison 5863** 5864** ^The [sqlite3_strnicmp()] API allows applications and extensions to 5865** compare the contents of two buffers containing UTF-8 strings in a 5866** case-independent fashion, using the same definition of case independence 5867** that SQLite uses internally when comparing identifiers. 5868*/ 5869int sqlite3_strnicmp(const char *, const char *, int); 5870 5871/* 5872** CAPI3REF: Error Logging Interface 5873** 5874** ^The [sqlite3_log()] interface writes a message into the error log 5875** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 5876** ^If logging is enabled, the zFormat string and subsequent arguments are 5877** used with [sqlite3_snprintf()] to generate the final output string. 5878** 5879** The sqlite3_log() interface is intended for use by extensions such as 5880** virtual tables, collating functions, and SQL functions. While there is 5881** nothing to prevent an application from calling sqlite3_log(), doing so 5882** is considered bad form. 5883** 5884** The zFormat string must not be NULL. 5885** 5886** To avoid deadlocks and other threading problems, the sqlite3_log() routine 5887** will not use dynamically allocated memory. The log message is stored in 5888** a fixed-length buffer on the stack. If the log message is longer than 5889** a few hundred characters, it will be truncated to the length of the 5890** buffer. 5891*/ 5892void sqlite3_log(int iErrCode, const char *zFormat, ...); 5893 5894/* 5895** CAPI3REF: Write-Ahead Log Commit Hook 5896** 5897** ^The [sqlite3_wal_hook()] function is used to register a callback that 5898** will be invoked each time a database connection commits data to a 5899** [write-ahead log] (i.e. whenever a transaction is committed in 5900** [journal_mode | journal_mode=WAL mode]). 5901** 5902** ^The callback is invoked by SQLite after the commit has taken place and 5903** the associated write-lock on the database released, so the implementation 5904** may read, write or [checkpoint] the database as required. 5905** 5906** ^The first parameter passed to the callback function when it is invoked 5907** is a copy of the third parameter passed to sqlite3_wal_hook() when 5908** registering the callback. ^The second is a copy of the database handle. 5909** ^The third parameter is the name of the database that was written to - 5910** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 5911** is the number of pages currently in the write-ahead log file, 5912** including those that were just committed. 5913** 5914** The callback function should normally return [SQLITE_OK]. ^If an error 5915** code is returned, that error will propagate back up through the 5916** SQLite code base to cause the statement that provoked the callback 5917** to report an error, though the commit will have still occurred. If the 5918** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 5919** that does not correspond to any valid SQLite error code, the results 5920** are undefined. 5921** 5922** A single database handle may have at most a single write-ahead log callback 5923** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 5924** previously registered write-ahead log callback. ^Note that the 5925** [sqlite3_wal_autocheckpoint()] interface and the 5926** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 5927** those overwrite any prior [sqlite3_wal_hook()] settings. 5928*/ 5929void *sqlite3_wal_hook( 5930 sqlite3*, 5931 int(*)(void *,sqlite3*,const char*,int), 5932 void* 5933); 5934 5935/* 5936** CAPI3REF: Configure an auto-checkpoint 5937** 5938** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 5939** [sqlite3_wal_hook()] that causes any database on [database connection] D 5940** to automatically [checkpoint] 5941** after committing a transaction if there are N or 5942** more frames in the [write-ahead log] file. ^Passing zero or 5943** a negative value as the nFrame parameter disables automatic 5944** checkpoints entirely. 5945** 5946** ^The callback registered by this function replaces any existing callback 5947** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 5948** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 5949** configured by this function. 5950** 5951** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 5952** from SQL. 5953** 5954** ^Every new [database connection] defaults to having the auto-checkpoint 5955** enabled with a threshold of 1000 pages. The use of this interface 5956** is only necessary if the default setting is found to be suboptimal 5957** for a particular application. 5958*/ 5959int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 5960 5961/* 5962** CAPI3REF: Checkpoint a database 5963** 5964** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 5965** on [database connection] D to be [checkpointed]. ^If X is NULL or an 5966** empty string, then a checkpoint is run on all databases of 5967** connection D. ^If the database connection D is not in 5968** [WAL | write-ahead log mode] then this interface is a harmless no-op. 5969** 5970** ^The [wal_checkpoint pragma] can be used to invoke this interface 5971** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 5972** [wal_autocheckpoint pragma] can be used to cause this interface to be 5973** run whenever the WAL reaches a certain size threshold. 5974*/ 5975int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 5976 5977/* 5978** Undo the hack that converts floating point types to integer for 5979** builds on processors without floating point support. 5980*/ 5981#ifdef SQLITE_OMIT_FLOATING_POINT 5982# undef double 5983#endif 5984 5985#ifdef __cplusplus 5986} /* End of the 'extern "C"' block */ 5987#endif 5988#endif 5989