1/* 2** 2001 September 15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are suppose to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef _SQLITE3_H_ 34#define _SQLITE3_H_ 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Add the ability to override 'extern' 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51 52/* 53** These no-op macros are used in front of interfaces to mark those 54** interfaces as either deprecated or experimental. New applications 55** should not use deprecated interfaces - they are support for backwards 56** compatibility only. Application writers should be aware that 57** experimental interfaces are subject to change in point releases. 58** 59** These macros used to resolve to various kinds of compiler magic that 60** would generate warning messages when they were used. But that 61** compiler magic ended up generating such a flurry of bug reports 62** that we have taken it all out and gone back to using simple 63** noop macros. 64*/ 65#define SQLITE_DEPRECATED 66#define SQLITE_EXPERIMENTAL 67 68/* 69** Ensure these symbols were not defined by some previous header file. 70*/ 71#ifdef SQLITE_VERSION 72# undef SQLITE_VERSION 73#endif 74#ifdef SQLITE_VERSION_NUMBER 75# undef SQLITE_VERSION_NUMBER 76#endif 77 78/* 79** CAPI3REF: Compile-Time Library Version Numbers 80** 81** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 82** evaluates to a string literal that is the SQLite version in the 83** format "X.Y.Z" where X is the major version number (always 3 for 84** SQLite3) and Y is the minor version number and Z is the release number.)^ 85** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 86** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 87** numbers used in [SQLITE_VERSION].)^ 88** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 89** be larger than the release from which it is derived. Either Y will 90** be held constant and Z will be incremented or else Y will be incremented 91** and Z will be reset to zero. 92** 93** Since version 3.6.18, SQLite source code has been stored in the 94** <a href="http://www.fossil-scm.org/">Fossil configuration management 95** system</a>. ^The SQLITE_SOURCE_ID macro evalutes to 96** a string which identifies a particular check-in of SQLite 97** within its configuration management system. ^The SQLITE_SOURCE_ID 98** string contains the date and time of the check-in (UTC) and an SHA1 99** hash of the entire source tree. 100** 101** See also: [sqlite3_libversion()], 102** [sqlite3_libversion_number()], [sqlite3_sourceid()], 103** [sqlite_version()] and [sqlite_source_id()]. 104*/ 105#define SQLITE_VERSION "--VERS--" 106#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 107#define SQLITE_SOURCE_ID "--SOURCE-ID--" 108 109/* 110** CAPI3REF: Run-Time Library Version Numbers 111** KEYWORDS: sqlite3_version, sqlite3_sourceid 112** 113** These interfaces provide the same information as the [SQLITE_VERSION], 114** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 115** but are associated with the library instead of the header file. ^(Cautious 116** programmers might include assert() statements in their application to 117** verify that values returned by these interfaces match the macros in 118** the header, and thus insure that the application is 119** compiled with matching library and header files. 120** 121** <blockquote><pre> 122** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 123** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 124** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 125** </pre></blockquote>)^ 126** 127** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 128** macro. ^The sqlite3_libversion() function returns a pointer to the 129** to the sqlite3_version[] string constant. The sqlite3_libversion() 130** function is provided for use in DLLs since DLL users usually do not have 131** direct access to string constants within the DLL. ^The 132** sqlite3_libversion_number() function returns an integer equal to 133** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 134** a pointer to a string constant whose value is the same as the 135** [SQLITE_SOURCE_ID] C preprocessor macro. 136** 137** See also: [sqlite_version()] and [sqlite_source_id()]. 138*/ 139SQLITE_EXTERN const char sqlite3_version[]; 140const char *sqlite3_libversion(void); 141const char *sqlite3_sourceid(void); 142int sqlite3_libversion_number(void); 143 144/* 145** CAPI3REF: Run-Time Library Compilation Options Diagnostics 146** 147** ^The sqlite3_compileoption_used() function returns 0 or 1 148** indicating whether the specified option was defined at 149** compile time. ^The SQLITE_ prefix may be omitted from the 150** option name passed to sqlite3_compileoption_used(). 151** 152** ^The sqlite3_compileoption_get() function allows interating 153** over the list of options that were defined at compile time by 154** returning the N-th compile time option string. ^If N is out of range, 155** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 156** prefix is omitted from any strings returned by 157** sqlite3_compileoption_get(). 158** 159** ^Support for the diagnostic functions sqlite3_compileoption_used() 160** and sqlite3_compileoption_get() may be omitted by specifing the 161** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 162** 163** See also: SQL functions [sqlite_compileoption_used()] and 164** [sqlite_compileoption_get()] and the [compile_options pragma]. 165*/ 166#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 167int sqlite3_compileoption_used(const char *zOptName); 168const char *sqlite3_compileoption_get(int N); 169#endif 170 171/* 172** CAPI3REF: Test To See If The Library Is Threadsafe 173** 174** ^The sqlite3_threadsafe() function returns zero if and only if 175** SQLite was compiled mutexing code omitted due to the 176** [SQLITE_THREADSAFE] compile-time option being set to 0. 177** 178** SQLite can be compiled with or without mutexes. When 179** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 180** are enabled and SQLite is threadsafe. When the 181** [SQLITE_THREADSAFE] macro is 0, 182** the mutexes are omitted. Without the mutexes, it is not safe 183** to use SQLite concurrently from more than one thread. 184** 185** Enabling mutexes incurs a measurable performance penalty. 186** So if speed is of utmost importance, it makes sense to disable 187** the mutexes. But for maximum safety, mutexes should be enabled. 188** ^The default behavior is for mutexes to be enabled. 189** 190** This interface can be used by an application to make sure that the 191** version of SQLite that it is linking against was compiled with 192** the desired setting of the [SQLITE_THREADSAFE] macro. 193** 194** This interface only reports on the compile-time mutex setting 195** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 196** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 197** can be fully or partially disabled using a call to [sqlite3_config()] 198** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 199** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the 200** sqlite3_threadsafe() function shows only the compile-time setting of 201** thread safety, not any run-time changes to that setting made by 202** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 203** is unchanged by calls to sqlite3_config().)^ 204** 205** See the [threading mode] documentation for additional information. 206*/ 207int sqlite3_threadsafe(void); 208 209/* 210** CAPI3REF: Database Connection Handle 211** KEYWORDS: {database connection} {database connections} 212** 213** Each open SQLite database is represented by a pointer to an instance of 214** the opaque structure named "sqlite3". It is useful to think of an sqlite3 215** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 216** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 217** is its destructor. There are many other interfaces (such as 218** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 219** [sqlite3_busy_timeout()] to name but three) that are methods on an 220** sqlite3 object. 221*/ 222typedef struct sqlite3 sqlite3; 223 224/* 225** CAPI3REF: 64-Bit Integer Types 226** KEYWORDS: sqlite_int64 sqlite_uint64 227** 228** Because there is no cross-platform way to specify 64-bit integer types 229** SQLite includes typedefs for 64-bit signed and unsigned integers. 230** 231** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 232** The sqlite_int64 and sqlite_uint64 types are supported for backwards 233** compatibility only. 234** 235** ^The sqlite3_int64 and sqlite_int64 types can store integer values 236** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 237** sqlite3_uint64 and sqlite_uint64 types can store integer values 238** between 0 and +18446744073709551615 inclusive. 239*/ 240#ifdef SQLITE_INT64_TYPE 241 typedef SQLITE_INT64_TYPE sqlite_int64; 242 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 243#elif defined(_MSC_VER) || defined(__BORLANDC__) 244 typedef __int64 sqlite_int64; 245 typedef unsigned __int64 sqlite_uint64; 246#else 247 typedef long long int sqlite_int64; 248 typedef unsigned long long int sqlite_uint64; 249#endif 250typedef sqlite_int64 sqlite3_int64; 251typedef sqlite_uint64 sqlite3_uint64; 252 253/* 254** If compiling for a processor that lacks floating point support, 255** substitute integer for floating-point. 256*/ 257#ifdef SQLITE_OMIT_FLOATING_POINT 258# define double sqlite3_int64 259#endif 260 261/* 262** CAPI3REF: Closing A Database Connection 263** 264** ^The sqlite3_close() routine is the destructor for the [sqlite3] object. 265** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is 266** successfullly destroyed and all associated resources are deallocated. 267** 268** Applications must [sqlite3_finalize | finalize] all [prepared statements] 269** and [sqlite3_blob_close | close] all [BLOB handles] associated with 270** the [sqlite3] object prior to attempting to close the object. ^If 271** sqlite3_close() is called on a [database connection] that still has 272** outstanding [prepared statements] or [BLOB handles], then it returns 273** SQLITE_BUSY. 274** 275** ^If [sqlite3_close()] is invoked while a transaction is open, 276** the transaction is automatically rolled back. 277** 278** The C parameter to [sqlite3_close(C)] must be either a NULL 279** pointer or an [sqlite3] object pointer obtained 280** from [sqlite3_open()], [sqlite3_open16()], or 281** [sqlite3_open_v2()], and not previously closed. 282** ^Calling sqlite3_close() with a NULL pointer argument is a 283** harmless no-op. 284*/ 285int sqlite3_close(sqlite3 *); 286 287/* 288** The type for a callback function. 289** This is legacy and deprecated. It is included for historical 290** compatibility and is not documented. 291*/ 292typedef int (*sqlite3_callback)(void*,int,char**, char**); 293 294/* 295** CAPI3REF: One-Step Query Execution Interface 296** 297** The sqlite3_exec() interface is a convenience wrapper around 298** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 299** that allows an application to run multiple statements of SQL 300** without having to use a lot of C code. 301** 302** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 303** semicolon-separate SQL statements passed into its 2nd argument, 304** in the context of the [database connection] passed in as its 1st 305** argument. ^If the callback function of the 3rd argument to 306** sqlite3_exec() is not NULL, then it is invoked for each result row 307** coming out of the evaluated SQL statements. ^The 4th argument to 308** to sqlite3_exec() is relayed through to the 1st argument of each 309** callback invocation. ^If the callback pointer to sqlite3_exec() 310** is NULL, then no callback is ever invoked and result rows are 311** ignored. 312** 313** ^If an error occurs while evaluating the SQL statements passed into 314** sqlite3_exec(), then execution of the current statement stops and 315** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 316** is not NULL then any error message is written into memory obtained 317** from [sqlite3_malloc()] and passed back through the 5th parameter. 318** To avoid memory leaks, the application should invoke [sqlite3_free()] 319** on error message strings returned through the 5th parameter of 320** of sqlite3_exec() after the error message string is no longer needed. 321** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 322** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 323** NULL before returning. 324** 325** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 326** routine returns SQLITE_ABORT without invoking the callback again and 327** without running any subsequent SQL statements. 328** 329** ^The 2nd argument to the sqlite3_exec() callback function is the 330** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 331** callback is an array of pointers to strings obtained as if from 332** [sqlite3_column_text()], one for each column. ^If an element of a 333** result row is NULL then the corresponding string pointer for the 334** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 335** sqlite3_exec() callback is an array of pointers to strings where each 336** entry represents the name of corresponding result column as obtained 337** from [sqlite3_column_name()]. 338** 339** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 340** to an empty string, or a pointer that contains only whitespace and/or 341** SQL comments, then no SQL statements are evaluated and the database 342** is not changed. 343** 344** Restrictions: 345** 346** <ul> 347** <li> The application must insure that the 1st parameter to sqlite3_exec() 348** is a valid and open [database connection]. 349** <li> The application must not close [database connection] specified by 350** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 351** <li> The application must not modify the SQL statement text passed into 352** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 353** </ul> 354*/ 355int sqlite3_exec( 356 sqlite3*, /* An open database */ 357 const char *sql, /* SQL to be evaluated */ 358 int (*callback)(void*,int,char**,char**), /* Callback function */ 359 void *, /* 1st argument to callback */ 360 char **errmsg /* Error msg written here */ 361); 362 363/* 364** CAPI3REF: Result Codes 365** KEYWORDS: SQLITE_OK {error code} {error codes} 366** KEYWORDS: {result code} {result codes} 367** 368** Many SQLite functions return an integer result code from the set shown 369** here in order to indicates success or failure. 370** 371** New error codes may be added in future versions of SQLite. 372** 373** See also: [SQLITE_IOERR_READ | extended result codes] 374*/ 375#define SQLITE_OK 0 /* Successful result */ 376/* beginning-of-error-codes */ 377#define SQLITE_ERROR 1 /* SQL error or missing database */ 378#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 379#define SQLITE_PERM 3 /* Access permission denied */ 380#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 381#define SQLITE_BUSY 5 /* The database file is locked */ 382#define SQLITE_LOCKED 6 /* A table in the database is locked */ 383#define SQLITE_NOMEM 7 /* A malloc() failed */ 384#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 385#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 386#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 387#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 388#define SQLITE_NOTFOUND 12 /* NOT USED. Table or record not found */ 389#define SQLITE_FULL 13 /* Insertion failed because database is full */ 390#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 391#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 392#define SQLITE_EMPTY 16 /* Database is empty */ 393#define SQLITE_SCHEMA 17 /* The database schema changed */ 394#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 395#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 396#define SQLITE_MISMATCH 20 /* Data type mismatch */ 397#define SQLITE_MISUSE 21 /* Library used incorrectly */ 398#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 399#define SQLITE_AUTH 23 /* Authorization denied */ 400#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 401#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 402#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 403#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 404#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 405/* end-of-error-codes */ 406 407/* 408** CAPI3REF: Extended Result Codes 409** KEYWORDS: {extended error code} {extended error codes} 410** KEYWORDS: {extended result code} {extended result codes} 411** 412** In its default configuration, SQLite API routines return one of 26 integer 413** [SQLITE_OK | result codes]. However, experience has shown that many of 414** these result codes are too coarse-grained. They do not provide as 415** much information about problems as programmers might like. In an effort to 416** address this, newer versions of SQLite (version 3.3.8 and later) include 417** support for additional result codes that provide more detailed information 418** about errors. The extended result codes are enabled or disabled 419** on a per database connection basis using the 420** [sqlite3_extended_result_codes()] API. 421** 422** Some of the available extended result codes are listed here. 423** One may expect the number of extended result codes will be expand 424** over time. Software that uses extended result codes should expect 425** to see new result codes in future releases of SQLite. 426** 427** The SQLITE_OK result code will never be extended. It will always 428** be exactly zero. 429*/ 430#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 431#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 432#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 433#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 434#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 435#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 436#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 437#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 438#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 439#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 440#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 441#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 442#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 443#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 444#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 445#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 446#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 447#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 448#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 449#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 450#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 451#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 452#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 453 454/* 455** CAPI3REF: Flags For File Open Operations 456** 457** These bit values are intended for use in the 458** 3rd parameter to the [sqlite3_open_v2()] interface and 459** in the 4th parameter to the xOpen method of the 460** [sqlite3_vfs] object. 461*/ 462#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 463#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 464#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 465#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 466#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 467#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 468#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 469#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 470#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 471#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 472#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 473#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 474#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 475#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 476#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 477#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 478#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 479#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#define SQLITE_FCNTL_LOCKSTATE 1 695#define SQLITE_GET_LOCKPROXYFILE 2 696#define SQLITE_SET_LOCKPROXYFILE 3 697#define SQLITE_LAST_ERRNO 4 698#define SQLITE_FCNTL_SIZE_HINT 5 699 700/* 701** CAPI3REF: Mutex Handle 702** 703** The mutex module within SQLite defines [sqlite3_mutex] to be an 704** abstract type for a mutex object. The SQLite core never looks 705** at the internal representation of an [sqlite3_mutex]. It only 706** deals with pointers to the [sqlite3_mutex] object. 707** 708** Mutexes are created using [sqlite3_mutex_alloc()]. 709*/ 710typedef struct sqlite3_mutex sqlite3_mutex; 711 712/* 713** CAPI3REF: OS Interface Object 714** 715** An instance of the sqlite3_vfs object defines the interface between 716** the SQLite core and the underlying operating system. The "vfs" 717** in the name of the object stands for "virtual file system". 718** 719** The value of the iVersion field is initially 1 but may be larger in 720** future versions of SQLite. Additional fields may be appended to this 721** object when the iVersion value is increased. Note that the structure 722** of the sqlite3_vfs object changes in the transaction between 723** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 724** modified. 725** 726** The szOsFile field is the size of the subclassed [sqlite3_file] 727** structure used by this VFS. mxPathname is the maximum length of 728** a pathname in this VFS. 729** 730** Registered sqlite3_vfs objects are kept on a linked list formed by 731** the pNext pointer. The [sqlite3_vfs_register()] 732** and [sqlite3_vfs_unregister()] interfaces manage this list 733** in a thread-safe way. The [sqlite3_vfs_find()] interface 734** searches the list. Neither the application code nor the VFS 735** implementation should use the pNext pointer. 736** 737** The pNext field is the only field in the sqlite3_vfs 738** structure that SQLite will ever modify. SQLite will only access 739** or modify this field while holding a particular static mutex. 740** The application should never modify anything within the sqlite3_vfs 741** object once the object has been registered. 742** 743** The zName field holds the name of the VFS module. The name must 744** be unique across all VFS modules. 745** 746** SQLite will guarantee that the zFilename parameter to xOpen 747** is either a NULL pointer or string obtained 748** from xFullPathname(). SQLite further guarantees that 749** the string will be valid and unchanged until xClose() is 750** called. Because of the previous sentence, 751** the [sqlite3_file] can safely store a pointer to the 752** filename if it needs to remember the filename for some reason. 753** If the zFilename parameter is xOpen is a NULL pointer then xOpen 754** must invent its own temporary name for the file. Whenever the 755** xFilename parameter is NULL it will also be the case that the 756** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 757** 758** The flags argument to xOpen() includes all bits set in 759** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 760** or [sqlite3_open16()] is used, then flags includes at least 761** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 762** If xOpen() opens a file read-only then it sets *pOutFlags to 763** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 764** 765** SQLite will also add one of the following flags to the xOpen() 766** call, depending on the object being opened: 767** 768** <ul> 769** <li> [SQLITE_OPEN_MAIN_DB] 770** <li> [SQLITE_OPEN_MAIN_JOURNAL] 771** <li> [SQLITE_OPEN_TEMP_DB] 772** <li> [SQLITE_OPEN_TEMP_JOURNAL] 773** <li> [SQLITE_OPEN_TRANSIENT_DB] 774** <li> [SQLITE_OPEN_SUBJOURNAL] 775** <li> [SQLITE_OPEN_MASTER_JOURNAL] 776** </ul> 777** 778** The file I/O implementation can use the object type flags to 779** change the way it deals with files. For example, an application 780** that does not care about crash recovery or rollback might make 781** the open of a journal file a no-op. Writes to this journal would 782** also be no-ops, and any attempt to read the journal would return 783** SQLITE_IOERR. Or the implementation might recognize that a database 784** file will be doing page-aligned sector reads and writes in a random 785** order and set up its I/O subsystem accordingly. 786** 787** SQLite might also add one of the following flags to the xOpen method: 788** 789** <ul> 790** <li> [SQLITE_OPEN_DELETEONCLOSE] 791** <li> [SQLITE_OPEN_EXCLUSIVE] 792** </ul> 793** 794** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 795** deleted when it is closed. The [SQLITE_OPEN_DELETEONCLOSE] 796** will be set for TEMP databases, journals and for subjournals. 797** 798** The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 799** with the [SQLITE_OPEN_CREATE] flag, which are both directly 800** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 801** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 802** SQLITE_OPEN_CREATE, is used to indicate that file should always 803** be created, and that it is an error if it already exists. 804** It is <i>not</i> used to indicate the file should be opened 805** for exclusive access. 806** 807** At least szOsFile bytes of memory are allocated by SQLite 808** to hold the [sqlite3_file] structure passed as the third 809** argument to xOpen. The xOpen method does not have to 810** allocate the structure; it should just fill it in. Note that 811** the xOpen method must set the sqlite3_file.pMethods to either 812** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 813** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 814** element will be valid after xOpen returns regardless of the success 815** or failure of the xOpen call. 816** 817** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 818** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 819** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 820** to test whether a file is at least readable. The file can be a 821** directory. 822** 823** SQLite will always allocate at least mxPathname+1 bytes for the 824** output buffer xFullPathname. The exact size of the output buffer 825** is also passed as a parameter to both methods. If the output buffer 826** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 827** handled as a fatal error by SQLite, vfs implementations should endeavor 828** to prevent this by setting mxPathname to a sufficiently large value. 829** 830** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 831** interfaces are not strictly a part of the filesystem, but they are 832** included in the VFS structure for completeness. 833** The xRandomness() function attempts to return nBytes bytes 834** of good-quality randomness into zOut. The return value is 835** the actual number of bytes of randomness obtained. 836** The xSleep() method causes the calling thread to sleep for at 837** least the number of microseconds given. The xCurrentTime() 838** method returns a Julian Day Number for the current date and time as 839** a floating point value. 840** The xCurrentTimeInt64() method returns, as an integer, the Julian 841** Day Number multipled by 86400000 (the number of milliseconds in 842** a 24-hour day). 843** ^SQLite will use the xCurrentTimeInt64() method to get the current 844** date and time if that method is available (if iVersion is 2 or 845** greater and the function pointer is not NULL) and will fall back 846** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 847*/ 848typedef struct sqlite3_vfs sqlite3_vfs; 849struct sqlite3_vfs { 850 int iVersion; /* Structure version number (currently 2) */ 851 int szOsFile; /* Size of subclassed sqlite3_file */ 852 int mxPathname; /* Maximum file pathname length */ 853 sqlite3_vfs *pNext; /* Next registered VFS */ 854 const char *zName; /* Name of this virtual file system */ 855 void *pAppData; /* Pointer to application-specific data */ 856 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 857 int flags, int *pOutFlags); 858 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 859 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 860 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 861 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 862 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 863 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 864 void (*xDlClose)(sqlite3_vfs*, void*); 865 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 866 int (*xSleep)(sqlite3_vfs*, int microseconds); 867 int (*xCurrentTime)(sqlite3_vfs*, double*); 868 int (*xGetLastError)(sqlite3_vfs*, int, char *); 869 /* 870 ** The methods above are in version 1 of the sqlite_vfs object 871 ** definition. Those that follow are added in version 2 or later 872 */ 873 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 874 /* 875 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 876 ** New fields may be appended in figure versions. The iVersion 877 ** value will increment whenever this happens. 878 */ 879}; 880 881/* 882** CAPI3REF: Flags for the xAccess VFS method 883** 884** These integer constants can be used as the third parameter to 885** the xAccess method of an [sqlite3_vfs] object. They determine 886** what kind of permissions the xAccess method is looking for. 887** With SQLITE_ACCESS_EXISTS, the xAccess method 888** simply checks whether the file exists. 889** With SQLITE_ACCESS_READWRITE, the xAccess method 890** checks whether the named directory is both readable and writable 891** (in other words, if files can be added, removed, and renamed within 892** the directory). 893** The SQLITE_ACCESS_READWRITE constant is currently used only by the 894** [temp_store_directory pragma], though this could change in a future 895** release of SQLite. 896** With SQLITE_ACCESS_READ, the xAccess method 897** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 898** currently unused, though it might be used in a future release of 899** SQLite. 900*/ 901#define SQLITE_ACCESS_EXISTS 0 902#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 903#define SQLITE_ACCESS_READ 2 /* Unused */ 904 905/* 906** CAPI3REF: Flags for the xShmLock VFS method 907** 908** These integer constants define the various locking operations 909** allowed by the xShmLock method of [sqlite3_io_methods]. The 910** following are the only legal combinations of flags to the 911** xShmLock method: 912** 913** <ul> 914** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 915** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 916** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 917** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 918** </ul> 919** 920** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 921** was given no the corresponding lock. 922** 923** The xShmLock method can transition between unlocked and SHARED or 924** between unlocked and EXCLUSIVE. It cannot transition between SHARED 925** and EXCLUSIVE. 926*/ 927#define SQLITE_SHM_UNLOCK 1 928#define SQLITE_SHM_LOCK 2 929#define SQLITE_SHM_SHARED 4 930#define SQLITE_SHM_EXCLUSIVE 8 931 932/* 933** CAPI3REF: Maximum xShmLock index 934** 935** The xShmLock method on [sqlite3_io_methods] may use values 936** between 0 and this upper bound as its "offset" argument. 937** The SQLite core will never attempt to acquire or release a 938** lock outside of this range 939*/ 940#define SQLITE_SHM_NLOCK 8 941 942 943/* 944** CAPI3REF: Initialize The SQLite Library 945** 946** ^The sqlite3_initialize() routine initializes the 947** SQLite library. ^The sqlite3_shutdown() routine 948** deallocates any resources that were allocated by sqlite3_initialize(). 949** These routines are designed to aid in process initialization and 950** shutdown on embedded systems. Workstation applications using 951** SQLite normally do not need to invoke either of these routines. 952** 953** A call to sqlite3_initialize() is an "effective" call if it is 954** the first time sqlite3_initialize() is invoked during the lifetime of 955** the process, or if it is the first time sqlite3_initialize() is invoked 956** following a call to sqlite3_shutdown(). ^(Only an effective call 957** of sqlite3_initialize() does any initialization. All other calls 958** are harmless no-ops.)^ 959** 960** A call to sqlite3_shutdown() is an "effective" call if it is the first 961** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 962** an effective call to sqlite3_shutdown() does any deinitialization. 963** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 964** 965** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 966** is not. The sqlite3_shutdown() interface must only be called from a 967** single thread. All open [database connections] must be closed and all 968** other SQLite resources must be deallocated prior to invoking 969** sqlite3_shutdown(). 970** 971** Among other things, ^sqlite3_initialize() will invoke 972** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 973** will invoke sqlite3_os_end(). 974** 975** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 976** ^If for some reason, sqlite3_initialize() is unable to initialize 977** the library (perhaps it is unable to allocate a needed resource such 978** as a mutex) it returns an [error code] other than [SQLITE_OK]. 979** 980** ^The sqlite3_initialize() routine is called internally by many other 981** SQLite interfaces so that an application usually does not need to 982** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 983** calls sqlite3_initialize() so the SQLite library will be automatically 984** initialized when [sqlite3_open()] is called if it has not be initialized 985** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 986** compile-time option, then the automatic calls to sqlite3_initialize() 987** are omitted and the application must call sqlite3_initialize() directly 988** prior to using any other SQLite interface. For maximum portability, 989** it is recommended that applications always invoke sqlite3_initialize() 990** directly prior to using any other SQLite interface. Future releases 991** of SQLite may require this. In other words, the behavior exhibited 992** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 993** default behavior in some future release of SQLite. 994** 995** The sqlite3_os_init() routine does operating-system specific 996** initialization of the SQLite library. The sqlite3_os_end() 997** routine undoes the effect of sqlite3_os_init(). Typical tasks 998** performed by these routines include allocation or deallocation 999** of static resources, initialization of global variables, 1000** setting up a default [sqlite3_vfs] module, or setting up 1001** a default configuration using [sqlite3_config()]. 1002** 1003** The application should never invoke either sqlite3_os_init() 1004** or sqlite3_os_end() directly. The application should only invoke 1005** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1006** interface is called automatically by sqlite3_initialize() and 1007** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1008** implementations for sqlite3_os_init() and sqlite3_os_end() 1009** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1010** When [custom builds | built for other platforms] 1011** (using the [SQLITE_OS_OTHER=1] compile-time 1012** option) the application must supply a suitable implementation for 1013** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1014** implementation of sqlite3_os_init() or sqlite3_os_end() 1015** must return [SQLITE_OK] on success and some other [error code] upon 1016** failure. 1017*/ 1018int sqlite3_initialize(void); 1019int sqlite3_shutdown(void); 1020int sqlite3_os_init(void); 1021int sqlite3_os_end(void); 1022 1023/* 1024** CAPI3REF: Configuring The SQLite Library 1025** 1026** The sqlite3_config() interface is used to make global configuration 1027** changes to SQLite in order to tune SQLite to the specific needs of 1028** the application. The default configuration is recommended for most 1029** applications and so this routine is usually not necessary. It is 1030** provided to support rare applications with unusual needs. 1031** 1032** The sqlite3_config() interface is not threadsafe. The application 1033** must insure that no other SQLite interfaces are invoked by other 1034** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1035** may only be invoked prior to library initialization using 1036** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1037** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1038** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1039** Note, however, that ^sqlite3_config() can be called as part of the 1040** implementation of an application-defined [sqlite3_os_init()]. 1041** 1042** The first argument to sqlite3_config() is an integer 1043** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines 1044** what property of SQLite is to be configured. Subsequent arguments 1045** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option] 1046** in the first argument. 1047** 1048** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1049** ^If the option is unknown or SQLite is unable to set the option 1050** then this routine returns a non-zero [error code]. 1051*/ 1052int sqlite3_config(int, ...); 1053 1054/* 1055** CAPI3REF: Configure database connections 1056** 1057** The sqlite3_db_config() interface is used to make configuration 1058** changes to a [database connection]. The interface is similar to 1059** [sqlite3_config()] except that the changes apply to a single 1060** [database connection] (specified in the first argument). The 1061** sqlite3_db_config() interface should only be used immediately after 1062** the database connection is created using [sqlite3_open()], 1063** [sqlite3_open16()], or [sqlite3_open_v2()]. 1064** 1065** The second argument to sqlite3_db_config(D,V,...) is the 1066** configuration verb - an integer code that indicates what 1067** aspect of the [database connection] is being configured. 1068** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE]. 1069** New verbs are likely to be added in future releases of SQLite. 1070** Additional arguments depend on the verb. 1071** 1072** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1073** the call is considered successful. 1074*/ 1075int sqlite3_db_config(sqlite3*, int op, ...); 1076 1077/* 1078** CAPI3REF: Memory Allocation Routines 1079** 1080** An instance of this object defines the interface between SQLite 1081** and low-level memory allocation routines. 1082** 1083** This object is used in only one place in the SQLite interface. 1084** A pointer to an instance of this object is the argument to 1085** [sqlite3_config()] when the configuration option is 1086** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1087** By creating an instance of this object 1088** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1089** during configuration, an application can specify an alternative 1090** memory allocation subsystem for SQLite to use for all of its 1091** dynamic memory needs. 1092** 1093** Note that SQLite comes with several [built-in memory allocators] 1094** that are perfectly adequate for the overwhelming majority of applications 1095** and that this object is only useful to a tiny minority of applications 1096** with specialized memory allocation requirements. This object is 1097** also used during testing of SQLite in order to specify an alternative 1098** memory allocator that simulates memory out-of-memory conditions in 1099** order to verify that SQLite recovers gracefully from such 1100** conditions. 1101** 1102** The xMalloc and xFree methods must work like the 1103** malloc() and free() functions from the standard C library. 1104** The xRealloc method must work like realloc() from the standard C library 1105** with the exception that if the second argument to xRealloc is zero, 1106** xRealloc must be a no-op - it must not perform any allocation or 1107** deallocation. ^SQLite guarantees that the second argument to 1108** xRealloc is always a value returned by a prior call to xRoundup. 1109** And so in cases where xRoundup always returns a positive number, 1110** xRealloc can perform exactly as the standard library realloc() and 1111** still be in compliance with this specification. 1112** 1113** xSize should return the allocated size of a memory allocation 1114** previously obtained from xMalloc or xRealloc. The allocated size 1115** is always at least as big as the requested size but may be larger. 1116** 1117** The xRoundup method returns what would be the allocated size of 1118** a memory allocation given a particular requested size. Most memory 1119** allocators round up memory allocations at least to the next multiple 1120** of 8. Some allocators round up to a larger multiple or to a power of 2. 1121** Every memory allocation request coming in through [sqlite3_malloc()] 1122** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1123** that causes the corresponding memory allocation to fail. 1124** 1125** The xInit method initializes the memory allocator. (For example, 1126** it might allocate any require mutexes or initialize internal data 1127** structures. The xShutdown method is invoked (indirectly) by 1128** [sqlite3_shutdown()] and should deallocate any resources acquired 1129** by xInit. The pAppData pointer is used as the only parameter to 1130** xInit and xShutdown. 1131** 1132** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1133** the xInit method, so the xInit method need not be threadsafe. The 1134** xShutdown method is only called from [sqlite3_shutdown()] so it does 1135** not need to be threadsafe either. For all other methods, SQLite 1136** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1137** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1138** it is by default) and so the methods are automatically serialized. 1139** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1140** methods must be threadsafe or else make their own arrangements for 1141** serialization. 1142** 1143** SQLite will never invoke xInit() more than once without an intervening 1144** call to xShutdown(). 1145*/ 1146typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1147struct sqlite3_mem_methods { 1148 void *(*xMalloc)(int); /* Memory allocation function */ 1149 void (*xFree)(void*); /* Free a prior allocation */ 1150 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1151 int (*xSize)(void*); /* Return the size of an allocation */ 1152 int (*xRoundup)(int); /* Round up request size to allocation size */ 1153 int (*xInit)(void*); /* Initialize the memory allocator */ 1154 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1155 void *pAppData; /* Argument to xInit() and xShutdown() */ 1156}; 1157 1158/* 1159** CAPI3REF: Configuration Options 1160** 1161** These constants are the available integer configuration options that 1162** can be passed as the first argument to the [sqlite3_config()] interface. 1163** 1164** New configuration options may be added in future releases of SQLite. 1165** Existing configuration options might be discontinued. Applications 1166** should check the return code from [sqlite3_config()] to make sure that 1167** the call worked. The [sqlite3_config()] interface will return a 1168** non-zero [error code] if a discontinued or unsupported configuration option 1169** is invoked. 1170** 1171** <dl> 1172** <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1173** <dd>There are no arguments to this option. ^This option sets the 1174** [threading mode] to Single-thread. In other words, it disables 1175** all mutexing and puts SQLite into a mode where it can only be used 1176** by a single thread. ^If SQLite is compiled with 1177** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1178** it is not possible to change the [threading mode] from its default 1179** value of Single-thread and so [sqlite3_config()] will return 1180** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1181** configuration option.</dd> 1182** 1183** <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1184** <dd>There are no arguments to this option. ^This option sets the 1185** [threading mode] to Multi-thread. In other words, it disables 1186** mutexing on [database connection] and [prepared statement] objects. 1187** The application is responsible for serializing access to 1188** [database connections] and [prepared statements]. But other mutexes 1189** are enabled so that SQLite will be safe to use in a multi-threaded 1190** environment as long as no two threads attempt to use the same 1191** [database connection] at the same time. ^If SQLite is compiled with 1192** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1193** it is not possible to set the Multi-thread [threading mode] and 1194** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1195** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1196** 1197** <dt>SQLITE_CONFIG_SERIALIZED</dt> 1198** <dd>There are no arguments to this option. ^This option sets the 1199** [threading mode] to Serialized. In other words, this option enables 1200** all mutexes including the recursive 1201** mutexes on [database connection] and [prepared statement] objects. 1202** In this mode (which is the default when SQLite is compiled with 1203** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1204** to [database connections] and [prepared statements] so that the 1205** application is free to use the same [database connection] or the 1206** same [prepared statement] in different threads at the same time. 1207** ^If SQLite is compiled with 1208** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1209** it is not possible to set the Serialized [threading mode] and 1210** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1211** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1212** 1213** <dt>SQLITE_CONFIG_MALLOC</dt> 1214** <dd> ^(This option takes a single argument which is a pointer to an 1215** instance of the [sqlite3_mem_methods] structure. The argument specifies 1216** alternative low-level memory allocation routines to be used in place of 1217** the memory allocation routines built into SQLite.)^ ^SQLite makes 1218** its own private copy of the content of the [sqlite3_mem_methods] structure 1219** before the [sqlite3_config()] call returns.</dd> 1220** 1221** <dt>SQLITE_CONFIG_GETMALLOC</dt> 1222** <dd> ^(This option takes a single argument which is a pointer to an 1223** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1224** structure is filled with the currently defined memory allocation routines.)^ 1225** This option can be used to overload the default memory allocation 1226** routines with a wrapper that simulations memory allocation failure or 1227** tracks memory usage, for example. </dd> 1228** 1229** <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1230** <dd> ^This option takes single argument of type int, interpreted as a 1231** boolean, which enables or disables the collection of memory allocation 1232** statistics. ^(When memory allocation statistics are disabled, the 1233** following SQLite interfaces become non-operational: 1234** <ul> 1235** <li> [sqlite3_memory_used()] 1236** <li> [sqlite3_memory_highwater()] 1237** <li> [sqlite3_soft_heap_limit()] 1238** <li> [sqlite3_status()] 1239** </ul>)^ 1240** ^Memory allocation statistics are enabled by default unless SQLite is 1241** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1242** allocation statistics are disabled by default. 1243** </dd> 1244** 1245** <dt>SQLITE_CONFIG_SCRATCH</dt> 1246** <dd> ^This option specifies a static memory buffer that SQLite can use for 1247** scratch memory. There are three arguments: A pointer an 8-byte 1248** aligned memory buffer from which the scrach allocations will be 1249** drawn, the size of each scratch allocation (sz), 1250** and the maximum number of scratch allocations (N). The sz 1251** argument must be a multiple of 16. The sz parameter should be a few bytes 1252** larger than the actual scratch space required due to internal overhead. 1253** The first argument must be a pointer to an 8-byte aligned buffer 1254** of at least sz*N bytes of memory. 1255** ^SQLite will use no more than one scratch buffer per thread. So 1256** N should be set to the expected maximum number of threads. ^SQLite will 1257** never require a scratch buffer that is more than 6 times the database 1258** page size. ^If SQLite needs needs additional scratch memory beyond 1259** what is provided by this configuration option, then 1260** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1261** 1262** <dt>SQLITE_CONFIG_PAGECACHE</dt> 1263** <dd> ^This option specifies a static memory buffer that SQLite can use for 1264** the database page cache with the default page cache implemenation. 1265** This configuration should not be used if an application-define page 1266** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option. 1267** There are three arguments to this option: A pointer to 8-byte aligned 1268** memory, the size of each page buffer (sz), and the number of pages (N). 1269** The sz argument should be the size of the largest database page 1270** (a power of two between 512 and 32768) plus a little extra for each 1271** page header. ^The page header size is 20 to 40 bytes depending on 1272** the host architecture. ^It is harmless, apart from the wasted memory, 1273** to make sz a little too large. The first 1274** argument should point to an allocation of at least sz*N bytes of memory. 1275** ^SQLite will use the memory provided by the first argument to satisfy its 1276** memory needs for the first N pages that it adds to cache. ^If additional 1277** page cache memory is needed beyond what is provided by this option, then 1278** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1279** ^The implementation might use one or more of the N buffers to hold 1280** memory accounting information. The pointer in the first argument must 1281** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1282** will be undefined.</dd> 1283** 1284** <dt>SQLITE_CONFIG_HEAP</dt> 1285** <dd> ^This option specifies a static memory buffer that SQLite will use 1286** for all of its dynamic memory allocation needs beyond those provided 1287** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1288** There are three arguments: An 8-byte aligned pointer to the memory, 1289** the number of bytes in the memory buffer, and the minimum allocation size. 1290** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1291** to using its default memory allocator (the system malloc() implementation), 1292** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1293** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1294** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1295** allocator is engaged to handle all of SQLites memory allocation needs. 1296** The first pointer (the memory pointer) must be aligned to an 8-byte 1297** boundary or subsequent behavior of SQLite will be undefined.</dd> 1298** 1299** <dt>SQLITE_CONFIG_MUTEX</dt> 1300** <dd> ^(This option takes a single argument which is a pointer to an 1301** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1302** alternative low-level mutex routines to be used in place 1303** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1304** content of the [sqlite3_mutex_methods] structure before the call to 1305** [sqlite3_config()] returns. ^If SQLite is compiled with 1306** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1307** the entire mutexing subsystem is omitted from the build and hence calls to 1308** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1309** return [SQLITE_ERROR].</dd> 1310** 1311** <dt>SQLITE_CONFIG_GETMUTEX</dt> 1312** <dd> ^(This option takes a single argument which is a pointer to an 1313** instance of the [sqlite3_mutex_methods] structure. The 1314** [sqlite3_mutex_methods] 1315** structure is filled with the currently defined mutex routines.)^ 1316** This option can be used to overload the default mutex allocation 1317** routines with a wrapper used to track mutex usage for performance 1318** profiling or testing, for example. ^If SQLite is compiled with 1319** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1320** the entire mutexing subsystem is omitted from the build and hence calls to 1321** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1322** return [SQLITE_ERROR].</dd> 1323** 1324** <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1325** <dd> ^(This option takes two arguments that determine the default 1326** memory allocation for the lookaside memory allocator on each 1327** [database connection]. The first argument is the 1328** size of each lookaside buffer slot and the second is the number of 1329** slots allocated to each database connection.)^ ^(This option sets the 1330** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1331** verb to [sqlite3_db_config()] can be used to change the lookaside 1332** configuration on individual connections.)^ </dd> 1333** 1334** <dt>SQLITE_CONFIG_PCACHE</dt> 1335** <dd> ^(This option takes a single argument which is a pointer to 1336** an [sqlite3_pcache_methods] object. This object specifies the interface 1337** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1338** object and uses it for page cache memory allocations.</dd> 1339** 1340** <dt>SQLITE_CONFIG_GETPCACHE</dt> 1341** <dd> ^(This option takes a single argument which is a pointer to an 1342** [sqlite3_pcache_methods] object. SQLite copies of the current 1343** page cache implementation into that object.)^ </dd> 1344** 1345** <dt>SQLITE_CONFIG_LOG</dt> 1346** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1347** function with a call signature of void(*)(void*,int,const char*), 1348** and a pointer to void. ^If the function pointer is not NULL, it is 1349** invoked by [sqlite3_log()] to process each logging event. ^If the 1350** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1351** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1352** passed through as the first parameter to the application-defined logger 1353** function whenever that function is invoked. ^The second parameter to 1354** the logger function is a copy of the first parameter to the corresponding 1355** [sqlite3_log()] call and is intended to be a [result code] or an 1356** [extended result code]. ^The third parameter passed to the logger is 1357** log message after formatting via [sqlite3_snprintf()]. 1358** The SQLite logging interface is not reentrant; the logger function 1359** supplied by the application must not invoke any SQLite interface. 1360** In a multi-threaded application, the application-defined logger 1361** function must be threadsafe. </dd> 1362** 1363** </dl> 1364*/ 1365#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1366#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1367#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1368#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1369#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1370#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1371#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1372#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1373#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1374#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1375#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1376/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1377#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1378#define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */ 1379#define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */ 1380#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1381 1382/* 1383** CAPI3REF: Database Connection Configuration Options 1384** 1385** These constants are the available integer configuration options that 1386** can be passed as the second argument to the [sqlite3_db_config()] interface. 1387** 1388** New configuration options may be added in future releases of SQLite. 1389** Existing configuration options might be discontinued. Applications 1390** should check the return code from [sqlite3_db_config()] to make sure that 1391** the call worked. ^The [sqlite3_db_config()] interface will return a 1392** non-zero [error code] if a discontinued or unsupported configuration option 1393** is invoked. 1394** 1395** <dl> 1396** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1397** <dd> ^This option takes three additional arguments that determine the 1398** [lookaside memory allocator] configuration for the [database connection]. 1399** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1400** pointer to an memory buffer to use for lookaside memory. 1401** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1402** may be NULL in which case SQLite will allocate the 1403** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1404** size of each lookaside buffer slot. ^The third argument is the number of 1405** slots. The size of the buffer in the first argument must be greater than 1406** or equal to the product of the second and third arguments. The buffer 1407** must be aligned to an 8-byte boundary. ^If the second argument to 1408** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1409** rounded down to the next smaller 1410** multiple of 8. See also: [SQLITE_CONFIG_LOOKASIDE]</dd> 1411** 1412** </dl> 1413*/ 1414#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1415 1416 1417/* 1418** CAPI3REF: Enable Or Disable Extended Result Codes 1419** 1420** ^The sqlite3_extended_result_codes() routine enables or disables the 1421** [extended result codes] feature of SQLite. ^The extended result 1422** codes are disabled by default for historical compatibility. 1423*/ 1424int sqlite3_extended_result_codes(sqlite3*, int onoff); 1425 1426/* 1427** CAPI3REF: Last Insert Rowid 1428** 1429** ^Each entry in an SQLite table has a unique 64-bit signed 1430** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1431** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1432** names are not also used by explicitly declared columns. ^If 1433** the table has a column of type [INTEGER PRIMARY KEY] then that column 1434** is another alias for the rowid. 1435** 1436** ^This routine returns the [rowid] of the most recent 1437** successful [INSERT] into the database from the [database connection] 1438** in the first argument. ^If no successful [INSERT]s 1439** have ever occurred on that database connection, zero is returned. 1440** 1441** ^(If an [INSERT] occurs within a trigger, then the [rowid] of the inserted 1442** row is returned by this routine as long as the trigger is running. 1443** But once the trigger terminates, the value returned by this routine 1444** reverts to the last value inserted before the trigger fired.)^ 1445** 1446** ^An [INSERT] that fails due to a constraint violation is not a 1447** successful [INSERT] and does not change the value returned by this 1448** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1449** and INSERT OR ABORT make no changes to the return value of this 1450** routine when their insertion fails. ^(When INSERT OR REPLACE 1451** encounters a constraint violation, it does not fail. The 1452** INSERT continues to completion after deleting rows that caused 1453** the constraint problem so INSERT OR REPLACE will always change 1454** the return value of this interface.)^ 1455** 1456** ^For the purposes of this routine, an [INSERT] is considered to 1457** be successful even if it is subsequently rolled back. 1458** 1459** This function is accessible to SQL statements via the 1460** [last_insert_rowid() SQL function]. 1461** 1462** If a separate thread performs a new [INSERT] on the same 1463** database connection while the [sqlite3_last_insert_rowid()] 1464** function is running and thus changes the last insert [rowid], 1465** then the value returned by [sqlite3_last_insert_rowid()] is 1466** unpredictable and might not equal either the old or the new 1467** last insert [rowid]. 1468*/ 1469sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1470 1471/* 1472** CAPI3REF: Count The Number Of Rows Modified 1473** 1474** ^This function returns the number of database rows that were changed 1475** or inserted or deleted by the most recently completed SQL statement 1476** on the [database connection] specified by the first parameter. 1477** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1478** or [DELETE] statement are counted. Auxiliary changes caused by 1479** triggers or [foreign key actions] are not counted.)^ Use the 1480** [sqlite3_total_changes()] function to find the total number of changes 1481** including changes caused by triggers and foreign key actions. 1482** 1483** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1484** are not counted. Only real table changes are counted. 1485** 1486** ^(A "row change" is a change to a single row of a single table 1487** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1488** are changed as side effects of [REPLACE] constraint resolution, 1489** rollback, ABORT processing, [DROP TABLE], or by any other 1490** mechanisms do not count as direct row changes.)^ 1491** 1492** A "trigger context" is a scope of execution that begins and 1493** ends with the script of a [CREATE TRIGGER | trigger]. 1494** Most SQL statements are 1495** evaluated outside of any trigger. This is the "top level" 1496** trigger context. If a trigger fires from the top level, a 1497** new trigger context is entered for the duration of that one 1498** trigger. Subtriggers create subcontexts for their duration. 1499** 1500** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1501** not create a new trigger context. 1502** 1503** ^This function returns the number of direct row changes in the 1504** most recent INSERT, UPDATE, or DELETE statement within the same 1505** trigger context. 1506** 1507** ^Thus, when called from the top level, this function returns the 1508** number of changes in the most recent INSERT, UPDATE, or DELETE 1509** that also occurred at the top level. ^(Within the body of a trigger, 1510** the sqlite3_changes() interface can be called to find the number of 1511** changes in the most recently completed INSERT, UPDATE, or DELETE 1512** statement within the body of the same trigger. 1513** However, the number returned does not include changes 1514** caused by subtriggers since those have their own context.)^ 1515** 1516** See also the [sqlite3_total_changes()] interface, the 1517** [count_changes pragma], and the [changes() SQL function]. 1518** 1519** If a separate thread makes changes on the same database connection 1520** while [sqlite3_changes()] is running then the value returned 1521** is unpredictable and not meaningful. 1522*/ 1523int sqlite3_changes(sqlite3*); 1524 1525/* 1526** CAPI3REF: Total Number Of Rows Modified 1527** 1528** ^This function returns the number of row changes caused by [INSERT], 1529** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1530** ^(The count returned by sqlite3_total_changes() includes all changes 1531** from all [CREATE TRIGGER | trigger] contexts and changes made by 1532** [foreign key actions]. However, 1533** the count does not include changes used to implement [REPLACE] constraints, 1534** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1535** count does not include rows of views that fire an [INSTEAD OF trigger], 1536** though if the INSTEAD OF trigger makes changes of its own, those changes 1537** are counted.)^ 1538** ^The sqlite3_total_changes() function counts the changes as soon as 1539** the statement that makes them is completed (when the statement handle 1540** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1541** 1542** See also the [sqlite3_changes()] interface, the 1543** [count_changes pragma], and the [total_changes() SQL function]. 1544** 1545** If a separate thread makes changes on the same database connection 1546** while [sqlite3_total_changes()] is running then the value 1547** returned is unpredictable and not meaningful. 1548*/ 1549int sqlite3_total_changes(sqlite3*); 1550 1551/* 1552** CAPI3REF: Interrupt A Long-Running Query 1553** 1554** ^This function causes any pending database operation to abort and 1555** return at its earliest opportunity. This routine is typically 1556** called in response to a user action such as pressing "Cancel" 1557** or Ctrl-C where the user wants a long query operation to halt 1558** immediately. 1559** 1560** ^It is safe to call this routine from a thread different from the 1561** thread that is currently running the database operation. But it 1562** is not safe to call this routine with a [database connection] that 1563** is closed or might close before sqlite3_interrupt() returns. 1564** 1565** ^If an SQL operation is very nearly finished at the time when 1566** sqlite3_interrupt() is called, then it might not have an opportunity 1567** to be interrupted and might continue to completion. 1568** 1569** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1570** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1571** that is inside an explicit transaction, then the entire transaction 1572** will be rolled back automatically. 1573** 1574** ^The sqlite3_interrupt(D) call is in effect until all currently running 1575** SQL statements on [database connection] D complete. ^Any new SQL statements 1576** that are started after the sqlite3_interrupt() call and before the 1577** running statements reaches zero are interrupted as if they had been 1578** running prior to the sqlite3_interrupt() call. ^New SQL statements 1579** that are started after the running statement count reaches zero are 1580** not effected by the sqlite3_interrupt(). 1581** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1582** SQL statements is a no-op and has no effect on SQL statements 1583** that are started after the sqlite3_interrupt() call returns. 1584** 1585** If the database connection closes while [sqlite3_interrupt()] 1586** is running then bad things will likely happen. 1587*/ 1588void sqlite3_interrupt(sqlite3*); 1589 1590/* 1591** CAPI3REF: Determine If An SQL Statement Is Complete 1592** 1593** These routines are useful during command-line input to determine if the 1594** currently entered text seems to form a complete SQL statement or 1595** if additional input is needed before sending the text into 1596** SQLite for parsing. ^These routines return 1 if the input string 1597** appears to be a complete SQL statement. ^A statement is judged to be 1598** complete if it ends with a semicolon token and is not a prefix of a 1599** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1600** string literals or quoted identifier names or comments are not 1601** independent tokens (they are part of the token in which they are 1602** embedded) and thus do not count as a statement terminator. ^Whitespace 1603** and comments that follow the final semicolon are ignored. 1604** 1605** ^These routines return 0 if the statement is incomplete. ^If a 1606** memory allocation fails, then SQLITE_NOMEM is returned. 1607** 1608** ^These routines do not parse the SQL statements thus 1609** will not detect syntactically incorrect SQL. 1610** 1611** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1612** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1613** automatically by sqlite3_complete16(). If that initialization fails, 1614** then the return value from sqlite3_complete16() will be non-zero 1615** regardless of whether or not the input SQL is complete.)^ 1616** 1617** The input to [sqlite3_complete()] must be a zero-terminated 1618** UTF-8 string. 1619** 1620** The input to [sqlite3_complete16()] must be a zero-terminated 1621** UTF-16 string in native byte order. 1622*/ 1623int sqlite3_complete(const char *sql); 1624int sqlite3_complete16(const void *sql); 1625 1626/* 1627** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1628** 1629** ^This routine sets a callback function that might be invoked whenever 1630** an attempt is made to open a database table that another thread 1631** or process has locked. 1632** 1633** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1634** is returned immediately upon encountering the lock. ^If the busy callback 1635** is not NULL, then the callback might be invoked with two arguments. 1636** 1637** ^The first argument to the busy handler is a copy of the void* pointer which 1638** is the third argument to sqlite3_busy_handler(). ^The second argument to 1639** the busy handler callback is the number of times that the busy handler has 1640** been invoked for this locking event. ^If the 1641** busy callback returns 0, then no additional attempts are made to 1642** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1643** ^If the callback returns non-zero, then another attempt 1644** is made to open the database for reading and the cycle repeats. 1645** 1646** The presence of a busy handler does not guarantee that it will be invoked 1647** when there is lock contention. ^If SQLite determines that invoking the busy 1648** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1649** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1650** Consider a scenario where one process is holding a read lock that 1651** it is trying to promote to a reserved lock and 1652** a second process is holding a reserved lock that it is trying 1653** to promote to an exclusive lock. The first process cannot proceed 1654** because it is blocked by the second and the second process cannot 1655** proceed because it is blocked by the first. If both processes 1656** invoke the busy handlers, neither will make any progress. Therefore, 1657** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1658** will induce the first process to release its read lock and allow 1659** the second process to proceed. 1660** 1661** ^The default busy callback is NULL. 1662** 1663** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1664** when SQLite is in the middle of a large transaction where all the 1665** changes will not fit into the in-memory cache. SQLite will 1666** already hold a RESERVED lock on the database file, but it needs 1667** to promote this lock to EXCLUSIVE so that it can spill cache 1668** pages into the database file without harm to concurrent 1669** readers. ^If it is unable to promote the lock, then the in-memory 1670** cache will be left in an inconsistent state and so the error 1671** code is promoted from the relatively benign [SQLITE_BUSY] to 1672** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 1673** forces an automatic rollback of the changes. See the 1674** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1675** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1676** this is important. 1677** 1678** ^(There can only be a single busy handler defined for each 1679** [database connection]. Setting a new busy handler clears any 1680** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 1681** will also set or clear the busy handler. 1682** 1683** The busy callback should not take any actions which modify the 1684** database connection that invoked the busy handler. Any such actions 1685** result in undefined behavior. 1686** 1687** A busy handler must not close the database connection 1688** or [prepared statement] that invoked the busy handler. 1689*/ 1690int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1691 1692/* 1693** CAPI3REF: Set A Busy Timeout 1694** 1695** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1696** for a specified amount of time when a table is locked. ^The handler 1697** will sleep multiple times until at least "ms" milliseconds of sleeping 1698** have accumulated. ^After at least "ms" milliseconds of sleeping, 1699** the handler returns 0 which causes [sqlite3_step()] to return 1700** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1701** 1702** ^Calling this routine with an argument less than or equal to zero 1703** turns off all busy handlers. 1704** 1705** ^(There can only be a single busy handler for a particular 1706** [database connection] any any given moment. If another busy handler 1707** was defined (using [sqlite3_busy_handler()]) prior to calling 1708** this routine, that other busy handler is cleared.)^ 1709*/ 1710int sqlite3_busy_timeout(sqlite3*, int ms); 1711 1712/* 1713** CAPI3REF: Convenience Routines For Running Queries 1714** 1715** Definition: A <b>result table</b> is memory data structure created by the 1716** [sqlite3_get_table()] interface. A result table records the 1717** complete query results from one or more queries. 1718** 1719** The table conceptually has a number of rows and columns. But 1720** these numbers are not part of the result table itself. These 1721** numbers are obtained separately. Let N be the number of rows 1722** and M be the number of columns. 1723** 1724** A result table is an array of pointers to zero-terminated UTF-8 strings. 1725** There are (N+1)*M elements in the array. The first M pointers point 1726** to zero-terminated strings that contain the names of the columns. 1727** The remaining entries all point to query results. NULL values result 1728** in NULL pointers. All other values are in their UTF-8 zero-terminated 1729** string representation as returned by [sqlite3_column_text()]. 1730** 1731** A result table might consist of one or more memory allocations. 1732** It is not safe to pass a result table directly to [sqlite3_free()]. 1733** A result table should be deallocated using [sqlite3_free_table()]. 1734** 1735** As an example of the result table format, suppose a query result 1736** is as follows: 1737** 1738** <blockquote><pre> 1739** Name | Age 1740** ----------------------- 1741** Alice | 43 1742** Bob | 28 1743** Cindy | 21 1744** </pre></blockquote> 1745** 1746** There are two column (M==2) and three rows (N==3). Thus the 1747** result table has 8 entries. Suppose the result table is stored 1748** in an array names azResult. Then azResult holds this content: 1749** 1750** <blockquote><pre> 1751** azResult[0] = "Name"; 1752** azResult[1] = "Age"; 1753** azResult[2] = "Alice"; 1754** azResult[3] = "43"; 1755** azResult[4] = "Bob"; 1756** azResult[5] = "28"; 1757** azResult[6] = "Cindy"; 1758** azResult[7] = "21"; 1759** </pre></blockquote> 1760** 1761** ^The sqlite3_get_table() function evaluates one or more 1762** semicolon-separated SQL statements in the zero-terminated UTF-8 1763** string of its 2nd parameter and returns a result table to the 1764** pointer given in its 3rd parameter. 1765** 1766** After the application has finished with the result from sqlite3_get_table(), 1767** it should pass the result table pointer to sqlite3_free_table() in order to 1768** release the memory that was malloced. Because of the way the 1769** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1770** function must not try to call [sqlite3_free()] directly. Only 1771** [sqlite3_free_table()] is able to release the memory properly and safely. 1772** 1773** ^(The sqlite3_get_table() interface is implemented as a wrapper around 1774** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 1775** to any internal data structures of SQLite. It uses only the public 1776** interface defined here. As a consequence, errors that occur in the 1777** wrapper layer outside of the internal [sqlite3_exec()] call are not 1778** reflected in subsequent calls to [sqlite3_errcode()] or 1779** [sqlite3_errmsg()].)^ 1780*/ 1781int sqlite3_get_table( 1782 sqlite3 *db, /* An open database */ 1783 const char *zSql, /* SQL to be evaluated */ 1784 char ***pazResult, /* Results of the query */ 1785 int *pnRow, /* Number of result rows written here */ 1786 int *pnColumn, /* Number of result columns written here */ 1787 char **pzErrmsg /* Error msg written here */ 1788); 1789void sqlite3_free_table(char **result); 1790 1791/* 1792** CAPI3REF: Formatted String Printing Functions 1793** 1794** These routines are work-alikes of the "printf()" family of functions 1795** from the standard C library. 1796** 1797** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 1798** results into memory obtained from [sqlite3_malloc()]. 1799** The strings returned by these two routines should be 1800** released by [sqlite3_free()]. ^Both routines return a 1801** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 1802** memory to hold the resulting string. 1803** 1804** ^(In sqlite3_snprintf() routine is similar to "snprintf()" from 1805** the standard C library. The result is written into the 1806** buffer supplied as the second parameter whose size is given by 1807** the first parameter. Note that the order of the 1808** first two parameters is reversed from snprintf().)^ This is an 1809** historical accident that cannot be fixed without breaking 1810** backwards compatibility. ^(Note also that sqlite3_snprintf() 1811** returns a pointer to its buffer instead of the number of 1812** characters actually written into the buffer.)^ We admit that 1813** the number of characters written would be a more useful return 1814** value but we cannot change the implementation of sqlite3_snprintf() 1815** now without breaking compatibility. 1816** 1817** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 1818** guarantees that the buffer is always zero-terminated. ^The first 1819** parameter "n" is the total size of the buffer, including space for 1820** the zero terminator. So the longest string that can be completely 1821** written will be n-1 characters. 1822** 1823** These routines all implement some additional formatting 1824** options that are useful for constructing SQL statements. 1825** All of the usual printf() formatting options apply. In addition, there 1826** is are "%q", "%Q", and "%z" options. 1827** 1828** ^(The %q option works like %s in that it substitutes a null-terminated 1829** string from the argument list. But %q also doubles every '\'' character. 1830** %q is designed for use inside a string literal.)^ By doubling each '\'' 1831** character it escapes that character and allows it to be inserted into 1832** the string. 1833** 1834** For example, assume the string variable zText contains text as follows: 1835** 1836** <blockquote><pre> 1837** char *zText = "It's a happy day!"; 1838** </pre></blockquote> 1839** 1840** One can use this text in an SQL statement as follows: 1841** 1842** <blockquote><pre> 1843** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 1844** sqlite3_exec(db, zSQL, 0, 0, 0); 1845** sqlite3_free(zSQL); 1846** </pre></blockquote> 1847** 1848** Because the %q format string is used, the '\'' character in zText 1849** is escaped and the SQL generated is as follows: 1850** 1851** <blockquote><pre> 1852** INSERT INTO table1 VALUES('It''s a happy day!') 1853** </pre></blockquote> 1854** 1855** This is correct. Had we used %s instead of %q, the generated SQL 1856** would have looked like this: 1857** 1858** <blockquote><pre> 1859** INSERT INTO table1 VALUES('It's a happy day!'); 1860** </pre></blockquote> 1861** 1862** This second example is an SQL syntax error. As a general rule you should 1863** always use %q instead of %s when inserting text into a string literal. 1864** 1865** ^(The %Q option works like %q except it also adds single quotes around 1866** the outside of the total string. Additionally, if the parameter in the 1867** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 1868** single quotes).)^ So, for example, one could say: 1869** 1870** <blockquote><pre> 1871** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 1872** sqlite3_exec(db, zSQL, 0, 0, 0); 1873** sqlite3_free(zSQL); 1874** </pre></blockquote> 1875** 1876** The code above will render a correct SQL statement in the zSQL 1877** variable even if the zText variable is a NULL pointer. 1878** 1879** ^(The "%z" formatting option works like "%s" but with the 1880** addition that after the string has been read and copied into 1881** the result, [sqlite3_free()] is called on the input string.)^ 1882*/ 1883char *sqlite3_mprintf(const char*,...); 1884char *sqlite3_vmprintf(const char*, va_list); 1885char *sqlite3_snprintf(int,char*,const char*, ...); 1886 1887/* 1888** CAPI3REF: Memory Allocation Subsystem 1889** 1890** The SQLite core uses these three routines for all of its own 1891** internal memory allocation needs. "Core" in the previous sentence 1892** does not include operating-system specific VFS implementation. The 1893** Windows VFS uses native malloc() and free() for some operations. 1894** 1895** ^The sqlite3_malloc() routine returns a pointer to a block 1896** of memory at least N bytes in length, where N is the parameter. 1897** ^If sqlite3_malloc() is unable to obtain sufficient free 1898** memory, it returns a NULL pointer. ^If the parameter N to 1899** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 1900** a NULL pointer. 1901** 1902** ^Calling sqlite3_free() with a pointer previously returned 1903** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 1904** that it might be reused. ^The sqlite3_free() routine is 1905** a no-op if is called with a NULL pointer. Passing a NULL pointer 1906** to sqlite3_free() is harmless. After being freed, memory 1907** should neither be read nor written. Even reading previously freed 1908** memory might result in a segmentation fault or other severe error. 1909** Memory corruption, a segmentation fault, or other severe error 1910** might result if sqlite3_free() is called with a non-NULL pointer that 1911** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 1912** 1913** ^(The sqlite3_realloc() interface attempts to resize a 1914** prior memory allocation to be at least N bytes, where N is the 1915** second parameter. The memory allocation to be resized is the first 1916** parameter.)^ ^ If the first parameter to sqlite3_realloc() 1917** is a NULL pointer then its behavior is identical to calling 1918** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 1919** ^If the second parameter to sqlite3_realloc() is zero or 1920** negative then the behavior is exactly the same as calling 1921** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 1922** ^sqlite3_realloc() returns a pointer to a memory allocation 1923** of at least N bytes in size or NULL if sufficient memory is unavailable. 1924** ^If M is the size of the prior allocation, then min(N,M) bytes 1925** of the prior allocation are copied into the beginning of buffer returned 1926** by sqlite3_realloc() and the prior allocation is freed. 1927** ^If sqlite3_realloc() returns NULL, then the prior allocation 1928** is not freed. 1929** 1930** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 1931** is always aligned to at least an 8 byte boundary. 1932** 1933** In SQLite version 3.5.0 and 3.5.1, it was possible to define 1934** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 1935** implementation of these routines to be omitted. That capability 1936** is no longer provided. Only built-in memory allocators can be used. 1937** 1938** The Windows OS interface layer calls 1939** the system malloc() and free() directly when converting 1940** filenames between the UTF-8 encoding used by SQLite 1941** and whatever filename encoding is used by the particular Windows 1942** installation. Memory allocation errors are detected, but 1943** they are reported back as [SQLITE_CANTOPEN] or 1944** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 1945** 1946** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 1947** must be either NULL or else pointers obtained from a prior 1948** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 1949** not yet been released. 1950** 1951** The application must not read or write any part of 1952** a block of memory after it has been released using 1953** [sqlite3_free()] or [sqlite3_realloc()]. 1954*/ 1955void *sqlite3_malloc(int); 1956void *sqlite3_realloc(void*, int); 1957void sqlite3_free(void*); 1958 1959/* 1960** CAPI3REF: Memory Allocator Statistics 1961** 1962** SQLite provides these two interfaces for reporting on the status 1963** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 1964** routines, which form the built-in memory allocation subsystem. 1965** 1966** ^The [sqlite3_memory_used()] routine returns the number of bytes 1967** of memory currently outstanding (malloced but not freed). 1968** ^The [sqlite3_memory_highwater()] routine returns the maximum 1969** value of [sqlite3_memory_used()] since the high-water mark 1970** was last reset. ^The values returned by [sqlite3_memory_used()] and 1971** [sqlite3_memory_highwater()] include any overhead 1972** added by SQLite in its implementation of [sqlite3_malloc()], 1973** but not overhead added by the any underlying system library 1974** routines that [sqlite3_malloc()] may call. 1975** 1976** ^The memory high-water mark is reset to the current value of 1977** [sqlite3_memory_used()] if and only if the parameter to 1978** [sqlite3_memory_highwater()] is true. ^The value returned 1979** by [sqlite3_memory_highwater(1)] is the high-water mark 1980** prior to the reset. 1981*/ 1982sqlite3_int64 sqlite3_memory_used(void); 1983sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 1984 1985/* 1986** CAPI3REF: Pseudo-Random Number Generator 1987** 1988** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 1989** select random [ROWID | ROWIDs] when inserting new records into a table that 1990** already uses the largest possible [ROWID]. The PRNG is also used for 1991** the build-in random() and randomblob() SQL functions. This interface allows 1992** applications to access the same PRNG for other purposes. 1993** 1994** ^A call to this routine stores N bytes of randomness into buffer P. 1995** 1996** ^The first time this routine is invoked (either internally or by 1997** the application) the PRNG is seeded using randomness obtained 1998** from the xRandomness method of the default [sqlite3_vfs] object. 1999** ^On all subsequent invocations, the pseudo-randomness is generated 2000** internally and without recourse to the [sqlite3_vfs] xRandomness 2001** method. 2002*/ 2003void sqlite3_randomness(int N, void *P); 2004 2005/* 2006** CAPI3REF: Compile-Time Authorization Callbacks 2007** 2008** ^This routine registers a authorizer callback with a particular 2009** [database connection], supplied in the first argument. 2010** ^The authorizer callback is invoked as SQL statements are being compiled 2011** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2012** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2013** points during the compilation process, as logic is being created 2014** to perform various actions, the authorizer callback is invoked to 2015** see if those actions are allowed. ^The authorizer callback should 2016** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2017** specific action but allow the SQL statement to continue to be 2018** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2019** rejected with an error. ^If the authorizer callback returns 2020** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2021** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2022** the authorizer will fail with an error message. 2023** 2024** When the callback returns [SQLITE_OK], that means the operation 2025** requested is ok. ^When the callback returns [SQLITE_DENY], the 2026** [sqlite3_prepare_v2()] or equivalent call that triggered the 2027** authorizer will fail with an error message explaining that 2028** access is denied. 2029** 2030** ^The first parameter to the authorizer callback is a copy of the third 2031** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2032** to the callback is an integer [SQLITE_COPY | action code] that specifies 2033** the particular action to be authorized. ^The third through sixth parameters 2034** to the callback are zero-terminated strings that contain additional 2035** details about the action to be authorized. 2036** 2037** ^If the action code is [SQLITE_READ] 2038** and the callback returns [SQLITE_IGNORE] then the 2039** [prepared statement] statement is constructed to substitute 2040** a NULL value in place of the table column that would have 2041** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2042** return can be used to deny an untrusted user access to individual 2043** columns of a table. 2044** ^If the action code is [SQLITE_DELETE] and the callback returns 2045** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2046** [truncate optimization] is disabled and all rows are deleted individually. 2047** 2048** An authorizer is used when [sqlite3_prepare | preparing] 2049** SQL statements from an untrusted source, to ensure that the SQL statements 2050** do not try to access data they are not allowed to see, or that they do not 2051** try to execute malicious statements that damage the database. For 2052** example, an application may allow a user to enter arbitrary 2053** SQL queries for evaluation by a database. But the application does 2054** not want the user to be able to make arbitrary changes to the 2055** database. An authorizer could then be put in place while the 2056** user-entered SQL is being [sqlite3_prepare | prepared] that 2057** disallows everything except [SELECT] statements. 2058** 2059** Applications that need to process SQL from untrusted sources 2060** might also consider lowering resource limits using [sqlite3_limit()] 2061** and limiting database size using the [max_page_count] [PRAGMA] 2062** in addition to using an authorizer. 2063** 2064** ^(Only a single authorizer can be in place on a database connection 2065** at a time. Each call to sqlite3_set_authorizer overrides the 2066** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2067** The authorizer is disabled by default. 2068** 2069** The authorizer callback must not do anything that will modify 2070** the database connection that invoked the authorizer callback. 2071** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2072** database connections for the meaning of "modify" in this paragraph. 2073** 2074** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2075** statement might be re-prepared during [sqlite3_step()] due to a 2076** schema change. Hence, the application should ensure that the 2077** correct authorizer callback remains in place during the [sqlite3_step()]. 2078** 2079** ^Note that the authorizer callback is invoked only during 2080** [sqlite3_prepare()] or its variants. Authorization is not 2081** performed during statement evaluation in [sqlite3_step()], unless 2082** as stated in the previous paragraph, sqlite3_step() invokes 2083** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2084*/ 2085int sqlite3_set_authorizer( 2086 sqlite3*, 2087 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2088 void *pUserData 2089); 2090 2091/* 2092** CAPI3REF: Authorizer Return Codes 2093** 2094** The [sqlite3_set_authorizer | authorizer callback function] must 2095** return either [SQLITE_OK] or one of these two constants in order 2096** to signal SQLite whether or not the action is permitted. See the 2097** [sqlite3_set_authorizer | authorizer documentation] for additional 2098** information. 2099*/ 2100#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2101#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2102 2103/* 2104** CAPI3REF: Authorizer Action Codes 2105** 2106** The [sqlite3_set_authorizer()] interface registers a callback function 2107** that is invoked to authorize certain SQL statement actions. The 2108** second parameter to the callback is an integer code that specifies 2109** what action is being authorized. These are the integer action codes that 2110** the authorizer callback may be passed. 2111** 2112** These action code values signify what kind of operation is to be 2113** authorized. The 3rd and 4th parameters to the authorization 2114** callback function will be parameters or NULL depending on which of these 2115** codes is used as the second parameter. ^(The 5th parameter to the 2116** authorizer callback is the name of the database ("main", "temp", 2117** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2118** is the name of the inner-most trigger or view that is responsible for 2119** the access attempt or NULL if this access attempt is directly from 2120** top-level SQL code. 2121*/ 2122/******************************************* 3rd ************ 4th ***********/ 2123#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2124#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2125#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2126#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2127#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2128#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2129#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2130#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2131#define SQLITE_DELETE 9 /* Table Name NULL */ 2132#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2133#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2134#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2135#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2136#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2137#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2138#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2139#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2140#define SQLITE_INSERT 18 /* Table Name NULL */ 2141#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2142#define SQLITE_READ 20 /* Table Name Column Name */ 2143#define SQLITE_SELECT 21 /* NULL NULL */ 2144#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2145#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2146#define SQLITE_ATTACH 24 /* Filename NULL */ 2147#define SQLITE_DETACH 25 /* Database Name NULL */ 2148#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2149#define SQLITE_REINDEX 27 /* Index Name NULL */ 2150#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2151#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2152#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2153#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2154#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2155#define SQLITE_COPY 0 /* No longer used */ 2156 2157/* 2158** CAPI3REF: Tracing And Profiling Functions 2159** 2160** These routines register callback functions that can be used for 2161** tracing and profiling the execution of SQL statements. 2162** 2163** ^The callback function registered by sqlite3_trace() is invoked at 2164** various times when an SQL statement is being run by [sqlite3_step()]. 2165** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2166** SQL statement text as the statement first begins executing. 2167** ^(Additional sqlite3_trace() callbacks might occur 2168** as each triggered subprogram is entered. The callbacks for triggers 2169** contain a UTF-8 SQL comment that identifies the trigger.)^ 2170** 2171** ^The callback function registered by sqlite3_profile() is invoked 2172** as each SQL statement finishes. ^The profile callback contains 2173** the original statement text and an estimate of wall-clock time 2174** of how long that statement took to run. ^The profile callback 2175** time is in units of nanoseconds, however the current implementation 2176** is only capable of millisecond resolution so the six least significant 2177** digits in the time are meaningless. Future versions of SQLite 2178** might provide greater resolution on the profiler callback. The 2179** sqlite3_profile() function is considered experimental and is 2180** subject to change in future versions of SQLite. 2181*/ 2182void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2183SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2184 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2185 2186/* 2187** CAPI3REF: Query Progress Callbacks 2188** 2189** ^This routine configures a callback function - the 2190** progress callback - that is invoked periodically during long 2191** running calls to [sqlite3_exec()], [sqlite3_step()] and 2192** [sqlite3_get_table()]. An example use for this 2193** interface is to keep a GUI updated during a large query. 2194** 2195** ^If the progress callback returns non-zero, the operation is 2196** interrupted. This feature can be used to implement a 2197** "Cancel" button on a GUI progress dialog box. 2198** 2199** The progress handler must not do anything that will modify 2200** the database connection that invoked the progress handler. 2201** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2202** database connections for the meaning of "modify" in this paragraph. 2203** 2204*/ 2205void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2206 2207/* 2208** CAPI3REF: Opening A New Database Connection 2209** 2210** ^These routines open an SQLite database file whose name is given by the 2211** filename argument. ^The filename argument is interpreted as UTF-8 for 2212** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2213** order for sqlite3_open16(). ^(A [database connection] handle is usually 2214** returned in *ppDb, even if an error occurs. The only exception is that 2215** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2216** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2217** object.)^ ^(If the database is opened (and/or created) successfully, then 2218** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2219** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2220** an English language description of the error following a failure of any 2221** of the sqlite3_open() routines. 2222** 2223** ^The default encoding for the database will be UTF-8 if 2224** sqlite3_open() or sqlite3_open_v2() is called and 2225** UTF-16 in the native byte order if sqlite3_open16() is used. 2226** 2227** Whether or not an error occurs when it is opened, resources 2228** associated with the [database connection] handle should be released by 2229** passing it to [sqlite3_close()] when it is no longer required. 2230** 2231** The sqlite3_open_v2() interface works like sqlite3_open() 2232** except that it accepts two additional parameters for additional control 2233** over the new database connection. ^(The flags parameter to 2234** sqlite3_open_v2() can take one of 2235** the following three values, optionally combined with the 2236** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2237** and/or [SQLITE_OPEN_PRIVATECACHE] flags:)^ 2238** 2239** <dl> 2240** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2241** <dd>The database is opened in read-only mode. If the database does not 2242** already exist, an error is returned.</dd>)^ 2243** 2244** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2245** <dd>The database is opened for reading and writing if possible, or reading 2246** only if the file is write protected by the operating system. In either 2247** case the database must already exist, otherwise an error is returned.</dd>)^ 2248** 2249** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2250** <dd>The database is opened for reading and writing, and is creates it if 2251** it does not already exist. This is the behavior that is always used for 2252** sqlite3_open() and sqlite3_open16().</dd>)^ 2253** </dl> 2254** 2255** If the 3rd parameter to sqlite3_open_v2() is not one of the 2256** combinations shown above or one of the combinations shown above combined 2257** with the [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], 2258** [SQLITE_OPEN_SHAREDCACHE] and/or [SQLITE_OPEN_SHAREDCACHE] flags, 2259** then the behavior is undefined. 2260** 2261** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2262** opens in the multi-thread [threading mode] as long as the single-thread 2263** mode has not been set at compile-time or start-time. ^If the 2264** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2265** in the serialized [threading mode] unless single-thread was 2266** previously selected at compile-time or start-time. 2267** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2268** eligible to use [shared cache mode], regardless of whether or not shared 2269** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2270** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2271** participate in [shared cache mode] even if it is enabled. 2272** 2273** ^If the filename is ":memory:", then a private, temporary in-memory database 2274** is created for the connection. ^This in-memory database will vanish when 2275** the database connection is closed. Future versions of SQLite might 2276** make use of additional special filenames that begin with the ":" character. 2277** It is recommended that when a database filename actually does begin with 2278** a ":" character you should prefix the filename with a pathname such as 2279** "./" to avoid ambiguity. 2280** 2281** ^If the filename is an empty string, then a private, temporary 2282** on-disk database will be created. ^This private database will be 2283** automatically deleted as soon as the database connection is closed. 2284** 2285** ^The fourth parameter to sqlite3_open_v2() is the name of the 2286** [sqlite3_vfs] object that defines the operating system interface that 2287** the new database connection should use. ^If the fourth parameter is 2288** a NULL pointer then the default [sqlite3_vfs] object is used. 2289** 2290** <b>Note to Windows users:</b> The encoding used for the filename argument 2291** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2292** codepage is currently defined. Filenames containing international 2293** characters must be converted to UTF-8 prior to passing them into 2294** sqlite3_open() or sqlite3_open_v2(). 2295*/ 2296int sqlite3_open( 2297 const char *filename, /* Database filename (UTF-8) */ 2298 sqlite3 **ppDb /* OUT: SQLite db handle */ 2299); 2300int sqlite3_open16( 2301 const void *filename, /* Database filename (UTF-16) */ 2302 sqlite3 **ppDb /* OUT: SQLite db handle */ 2303); 2304int sqlite3_open_v2( 2305 const char *filename, /* Database filename (UTF-8) */ 2306 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2307 int flags, /* Flags */ 2308 const char *zVfs /* Name of VFS module to use */ 2309); 2310 2311/* 2312** CAPI3REF: Error Codes And Messages 2313** 2314** ^The sqlite3_errcode() interface returns the numeric [result code] or 2315** [extended result code] for the most recent failed sqlite3_* API call 2316** associated with a [database connection]. If a prior API call failed 2317** but the most recent API call succeeded, the return value from 2318** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2319** interface is the same except that it always returns the 2320** [extended result code] even when extended result codes are 2321** disabled. 2322** 2323** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2324** text that describes the error, as either UTF-8 or UTF-16 respectively. 2325** ^(Memory to hold the error message string is managed internally. 2326** The application does not need to worry about freeing the result. 2327** However, the error string might be overwritten or deallocated by 2328** subsequent calls to other SQLite interface functions.)^ 2329** 2330** When the serialized [threading mode] is in use, it might be the 2331** case that a second error occurs on a separate thread in between 2332** the time of the first error and the call to these interfaces. 2333** When that happens, the second error will be reported since these 2334** interfaces always report the most recent result. To avoid 2335** this, each thread can obtain exclusive use of the [database connection] D 2336** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2337** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2338** all calls to the interfaces listed here are completed. 2339** 2340** If an interface fails with SQLITE_MISUSE, that means the interface 2341** was invoked incorrectly by the application. In that case, the 2342** error code and message may or may not be set. 2343*/ 2344int sqlite3_errcode(sqlite3 *db); 2345int sqlite3_extended_errcode(sqlite3 *db); 2346const char *sqlite3_errmsg(sqlite3*); 2347const void *sqlite3_errmsg16(sqlite3*); 2348 2349/* 2350** CAPI3REF: SQL Statement Object 2351** KEYWORDS: {prepared statement} {prepared statements} 2352** 2353** An instance of this object represents a single SQL statement. 2354** This object is variously known as a "prepared statement" or a 2355** "compiled SQL statement" or simply as a "statement". 2356** 2357** The life of a statement object goes something like this: 2358** 2359** <ol> 2360** <li> Create the object using [sqlite3_prepare_v2()] or a related 2361** function. 2362** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2363** interfaces. 2364** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2365** <li> Reset the statement using [sqlite3_reset()] then go back 2366** to step 2. Do this zero or more times. 2367** <li> Destroy the object using [sqlite3_finalize()]. 2368** </ol> 2369** 2370** Refer to documentation on individual methods above for additional 2371** information. 2372*/ 2373typedef struct sqlite3_stmt sqlite3_stmt; 2374 2375/* 2376** CAPI3REF: Run-time Limits 2377** 2378** ^(This interface allows the size of various constructs to be limited 2379** on a connection by connection basis. The first parameter is the 2380** [database connection] whose limit is to be set or queried. The 2381** second parameter is one of the [limit categories] that define a 2382** class of constructs to be size limited. The third parameter is the 2383** new limit for that construct. The function returns the old limit.)^ 2384** 2385** ^If the new limit is a negative number, the limit is unchanged. 2386** ^(For the limit category of SQLITE_LIMIT_XYZ there is a 2387** [limits | hard upper bound] 2388** set by a compile-time C preprocessor macro named 2389** [limits | SQLITE_MAX_XYZ]. 2390** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2391** ^Attempts to increase a limit above its hard upper bound are 2392** silently truncated to the hard upper bound. 2393** 2394** Run-time limits are intended for use in applications that manage 2395** both their own internal database and also databases that are controlled 2396** by untrusted external sources. An example application might be a 2397** web browser that has its own databases for storing history and 2398** separate databases controlled by JavaScript applications downloaded 2399** off the Internet. The internal databases can be given the 2400** large, default limits. Databases managed by external sources can 2401** be given much smaller limits designed to prevent a denial of service 2402** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2403** interface to further control untrusted SQL. The size of the database 2404** created by an untrusted script can be contained using the 2405** [max_page_count] [PRAGMA]. 2406** 2407** New run-time limit categories may be added in future releases. 2408*/ 2409int sqlite3_limit(sqlite3*, int id, int newVal); 2410 2411/* 2412** CAPI3REF: Run-Time Limit Categories 2413** KEYWORDS: {limit category} {*limit categories} 2414** 2415** These constants define various performance limits 2416** that can be lowered at run-time using [sqlite3_limit()]. 2417** The synopsis of the meanings of the various limits is shown below. 2418** Additional information is available at [limits | Limits in SQLite]. 2419** 2420** <dl> 2421** ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2422** <dd>The maximum size of any string or BLOB or table row.<dd>)^ 2423** 2424** ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2425** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2426** 2427** ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2428** <dd>The maximum number of columns in a table definition or in the 2429** result set of a [SELECT] or the maximum number of columns in an index 2430** or in an ORDER BY or GROUP BY clause.</dd>)^ 2431** 2432** ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2433** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2434** 2435** ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2436** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2437** 2438** ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2439** <dd>The maximum number of instructions in a virtual machine program 2440** used to implement an SQL statement.</dd>)^ 2441** 2442** ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2443** <dd>The maximum number of arguments on a function.</dd>)^ 2444** 2445** ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2446** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2447** 2448** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2449** <dd>The maximum length of the pattern argument to the [LIKE] or 2450** [GLOB] operators.</dd>)^ 2451** 2452** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2453** <dd>The maximum number of variables in an SQL statement that can 2454** be bound.</dd>)^ 2455** 2456** ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2457** <dd>The maximum depth of recursion for triggers.</dd>)^ 2458** </dl> 2459*/ 2460#define SQLITE_LIMIT_LENGTH 0 2461#define SQLITE_LIMIT_SQL_LENGTH 1 2462#define SQLITE_LIMIT_COLUMN 2 2463#define SQLITE_LIMIT_EXPR_DEPTH 3 2464#define SQLITE_LIMIT_COMPOUND_SELECT 4 2465#define SQLITE_LIMIT_VDBE_OP 5 2466#define SQLITE_LIMIT_FUNCTION_ARG 6 2467#define SQLITE_LIMIT_ATTACHED 7 2468#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2469#define SQLITE_LIMIT_VARIABLE_NUMBER 9 2470#define SQLITE_LIMIT_TRIGGER_DEPTH 10 2471 2472/* 2473** CAPI3REF: Compiling An SQL Statement 2474** KEYWORDS: {SQL statement compiler} 2475** 2476** To execute an SQL query, it must first be compiled into a byte-code 2477** program using one of these routines. 2478** 2479** The first argument, "db", is a [database connection] obtained from a 2480** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2481** [sqlite3_open16()]. The database connection must not have been closed. 2482** 2483** The second argument, "zSql", is the statement to be compiled, encoded 2484** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2485** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2486** use UTF-16. 2487** 2488** ^If the nByte argument is less than zero, then zSql is read up to the 2489** first zero terminator. ^If nByte is non-negative, then it is the maximum 2490** number of bytes read from zSql. ^When nByte is non-negative, the 2491** zSql string ends at either the first '\000' or '\u0000' character or 2492** the nByte-th byte, whichever comes first. If the caller knows 2493** that the supplied string is nul-terminated, then there is a small 2494** performance advantage to be gained by passing an nByte parameter that 2495** is equal to the number of bytes in the input string <i>including</i> 2496** the nul-terminator bytes. 2497** 2498** ^If pzTail is not NULL then *pzTail is made to point to the first byte 2499** past the end of the first SQL statement in zSql. These routines only 2500** compile the first statement in zSql, so *pzTail is left pointing to 2501** what remains uncompiled. 2502** 2503** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 2504** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 2505** to NULL. ^If the input text contains no SQL (if the input is an empty 2506** string or a comment) then *ppStmt is set to NULL. 2507** The calling procedure is responsible for deleting the compiled 2508** SQL statement using [sqlite3_finalize()] after it has finished with it. 2509** ppStmt may not be NULL. 2510** 2511** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 2512** otherwise an [error code] is returned. 2513** 2514** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2515** recommended for all new programs. The two older interfaces are retained 2516** for backwards compatibility, but their use is discouraged. 2517** ^In the "v2" interfaces, the prepared statement 2518** that is returned (the [sqlite3_stmt] object) contains a copy of the 2519** original SQL text. This causes the [sqlite3_step()] interface to 2520** behave differently in three ways: 2521** 2522** <ol> 2523** <li> 2524** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2525** always used to do, [sqlite3_step()] will automatically recompile the SQL 2526** statement and try to run it again. ^If the schema has changed in 2527** a way that makes the statement no longer valid, [sqlite3_step()] will still 2528** return [SQLITE_SCHEMA]. But unlike the legacy behavior, [SQLITE_SCHEMA] is 2529** now a fatal error. Calling [sqlite3_prepare_v2()] again will not make the 2530** error go away. Note: use [sqlite3_errmsg()] to find the text 2531** of the parsing error that results in an [SQLITE_SCHEMA] return. 2532** </li> 2533** 2534** <li> 2535** ^When an error occurs, [sqlite3_step()] will return one of the detailed 2536** [error codes] or [extended error codes]. ^The legacy behavior was that 2537** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2538** and the application would have to make a second call to [sqlite3_reset()] 2539** in order to find the underlying cause of the problem. With the "v2" prepare 2540** interfaces, the underlying reason for the error is returned immediately. 2541** </li> 2542** 2543** <li> 2544** ^If the value of a [parameter | host parameter] in the WHERE clause might 2545** change the query plan for a statement, then the statement may be 2546** automatically recompiled (as if there had been a schema change) on the first 2547** [sqlite3_step()] call following any change to the 2548** [sqlite3_bind_text | bindings] of the [parameter]. 2549** </li> 2550** </ol> 2551*/ 2552int sqlite3_prepare( 2553 sqlite3 *db, /* Database handle */ 2554 const char *zSql, /* SQL statement, UTF-8 encoded */ 2555 int nByte, /* Maximum length of zSql in bytes. */ 2556 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2557 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2558); 2559int sqlite3_prepare_v2( 2560 sqlite3 *db, /* Database handle */ 2561 const char *zSql, /* SQL statement, UTF-8 encoded */ 2562 int nByte, /* Maximum length of zSql in bytes. */ 2563 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2564 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2565); 2566int sqlite3_prepare16( 2567 sqlite3 *db, /* Database handle */ 2568 const void *zSql, /* SQL statement, UTF-16 encoded */ 2569 int nByte, /* Maximum length of zSql in bytes. */ 2570 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2571 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2572); 2573int sqlite3_prepare16_v2( 2574 sqlite3 *db, /* Database handle */ 2575 const void *zSql, /* SQL statement, UTF-16 encoded */ 2576 int nByte, /* Maximum length of zSql in bytes. */ 2577 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2578 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2579); 2580 2581/* 2582** CAPI3REF: Retrieving Statement SQL 2583** 2584** ^This interface can be used to retrieve a saved copy of the original 2585** SQL text used to create a [prepared statement] if that statement was 2586** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2587*/ 2588const char *sqlite3_sql(sqlite3_stmt *pStmt); 2589 2590/* 2591** CAPI3REF: Dynamically Typed Value Object 2592** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 2593** 2594** SQLite uses the sqlite3_value object to represent all values 2595** that can be stored in a database table. SQLite uses dynamic typing 2596** for the values it stores. ^Values stored in sqlite3_value objects 2597** can be integers, floating point values, strings, BLOBs, or NULL. 2598** 2599** An sqlite3_value object may be either "protected" or "unprotected". 2600** Some interfaces require a protected sqlite3_value. Other interfaces 2601** will accept either a protected or an unprotected sqlite3_value. 2602** Every interface that accepts sqlite3_value arguments specifies 2603** whether or not it requires a protected sqlite3_value. 2604** 2605** The terms "protected" and "unprotected" refer to whether or not 2606** a mutex is held. A internal mutex is held for a protected 2607** sqlite3_value object but no mutex is held for an unprotected 2608** sqlite3_value object. If SQLite is compiled to be single-threaded 2609** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 2610** or if SQLite is run in one of reduced mutex modes 2611** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 2612** then there is no distinction between protected and unprotected 2613** sqlite3_value objects and they can be used interchangeably. However, 2614** for maximum code portability it is recommended that applications 2615** still make the distinction between between protected and unprotected 2616** sqlite3_value objects even when not strictly required. 2617** 2618** ^The sqlite3_value objects that are passed as parameters into the 2619** implementation of [application-defined SQL functions] are protected. 2620** ^The sqlite3_value object returned by 2621** [sqlite3_column_value()] is unprotected. 2622** Unprotected sqlite3_value objects may only be used with 2623** [sqlite3_result_value()] and [sqlite3_bind_value()]. 2624** The [sqlite3_value_blob | sqlite3_value_type()] family of 2625** interfaces require protected sqlite3_value objects. 2626*/ 2627typedef struct Mem sqlite3_value; 2628 2629/* 2630** CAPI3REF: SQL Function Context Object 2631** 2632** The context in which an SQL function executes is stored in an 2633** sqlite3_context object. ^A pointer to an sqlite3_context object 2634** is always first parameter to [application-defined SQL functions]. 2635** The application-defined SQL function implementation will pass this 2636** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 2637** [sqlite3_aggregate_context()], [sqlite3_user_data()], 2638** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 2639** and/or [sqlite3_set_auxdata()]. 2640*/ 2641typedef struct sqlite3_context sqlite3_context; 2642 2643/* 2644** CAPI3REF: Binding Values To Prepared Statements 2645** KEYWORDS: {host parameter} {host parameters} {host parameter name} 2646** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 2647** 2648** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 2649** literals may be replaced by a [parameter] that matches one of following 2650** templates: 2651** 2652** <ul> 2653** <li> ? 2654** <li> ?NNN 2655** <li> :VVV 2656** <li> @VVV 2657** <li> $VVV 2658** </ul> 2659** 2660** In the templates above, NNN represents an integer literal, 2661** and VVV represents an alphanumeric identifer.)^ ^The values of these 2662** parameters (also called "host parameter names" or "SQL parameters") 2663** can be set using the sqlite3_bind_*() routines defined here. 2664** 2665** ^The first argument to the sqlite3_bind_*() routines is always 2666** a pointer to the [sqlite3_stmt] object returned from 2667** [sqlite3_prepare_v2()] or its variants. 2668** 2669** ^The second argument is the index of the SQL parameter to be set. 2670** ^The leftmost SQL parameter has an index of 1. ^When the same named 2671** SQL parameter is used more than once, second and subsequent 2672** occurrences have the same index as the first occurrence. 2673** ^The index for named parameters can be looked up using the 2674** [sqlite3_bind_parameter_index()] API if desired. ^The index 2675** for "?NNN" parameters is the value of NNN. 2676** ^The NNN value must be between 1 and the [sqlite3_limit()] 2677** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 2678** 2679** ^The third argument is the value to bind to the parameter. 2680** 2681** ^(In those routines that have a fourth argument, its value is the 2682** number of bytes in the parameter. To be clear: the value is the 2683** number of <u>bytes</u> in the value, not the number of characters.)^ 2684** ^If the fourth parameter is negative, the length of the string is 2685** the number of bytes up to the first zero terminator. 2686** 2687** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 2688** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 2689** string after SQLite has finished with it. ^If the fifth argument is 2690** the special value [SQLITE_STATIC], then SQLite assumes that the 2691** information is in static, unmanaged space and does not need to be freed. 2692** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 2693** SQLite makes its own private copy of the data immediately, before 2694** the sqlite3_bind_*() routine returns. 2695** 2696** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 2697** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 2698** (just an integer to hold its size) while it is being processed. 2699** Zeroblobs are intended to serve as placeholders for BLOBs whose 2700** content is later written using 2701** [sqlite3_blob_open | incremental BLOB I/O] routines. 2702** ^A negative value for the zeroblob results in a zero-length BLOB. 2703** 2704** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 2705** for the [prepared statement] or with a prepared statement for which 2706** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 2707** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 2708** routine is passed a [prepared statement] that has been finalized, the 2709** result is undefined and probably harmful. 2710** 2711** ^Bindings are not cleared by the [sqlite3_reset()] routine. 2712** ^Unbound parameters are interpreted as NULL. 2713** 2714** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 2715** [error code] if anything goes wrong. 2716** ^[SQLITE_RANGE] is returned if the parameter 2717** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 2718** 2719** See also: [sqlite3_bind_parameter_count()], 2720** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 2721*/ 2722int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 2723int sqlite3_bind_double(sqlite3_stmt*, int, double); 2724int sqlite3_bind_int(sqlite3_stmt*, int, int); 2725int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 2726int sqlite3_bind_null(sqlite3_stmt*, int); 2727int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 2728int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 2729int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 2730int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 2731 2732/* 2733** CAPI3REF: Number Of SQL Parameters 2734** 2735** ^This routine can be used to find the number of [SQL parameters] 2736** in a [prepared statement]. SQL parameters are tokens of the 2737** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 2738** placeholders for values that are [sqlite3_bind_blob | bound] 2739** to the parameters at a later time. 2740** 2741** ^(This routine actually returns the index of the largest (rightmost) 2742** parameter. For all forms except ?NNN, this will correspond to the 2743** number of unique parameters. If parameters of the ?NNN form are used, 2744** there may be gaps in the list.)^ 2745** 2746** See also: [sqlite3_bind_blob|sqlite3_bind()], 2747** [sqlite3_bind_parameter_name()], and 2748** [sqlite3_bind_parameter_index()]. 2749*/ 2750int sqlite3_bind_parameter_count(sqlite3_stmt*); 2751 2752/* 2753** CAPI3REF: Name Of A Host Parameter 2754** 2755** ^The sqlite3_bind_parameter_name(P,N) interface returns 2756** the name of the N-th [SQL parameter] in the [prepared statement] P. 2757** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 2758** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 2759** respectively. 2760** In other words, the initial ":" or "$" or "@" or "?" 2761** is included as part of the name.)^ 2762** ^Parameters of the form "?" without a following integer have no name 2763** and are referred to as "nameless" or "anonymous parameters". 2764** 2765** ^The first host parameter has an index of 1, not 0. 2766** 2767** ^If the value N is out of range or if the N-th parameter is 2768** nameless, then NULL is returned. ^The returned string is 2769** always in UTF-8 encoding even if the named parameter was 2770** originally specified as UTF-16 in [sqlite3_prepare16()] or 2771** [sqlite3_prepare16_v2()]. 2772** 2773** See also: [sqlite3_bind_blob|sqlite3_bind()], 2774** [sqlite3_bind_parameter_count()], and 2775** [sqlite3_bind_parameter_index()]. 2776*/ 2777const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 2778 2779/* 2780** CAPI3REF: Index Of A Parameter With A Given Name 2781** 2782** ^Return the index of an SQL parameter given its name. ^The 2783** index value returned is suitable for use as the second 2784** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 2785** is returned if no matching parameter is found. ^The parameter 2786** name must be given in UTF-8 even if the original statement 2787** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 2788** 2789** See also: [sqlite3_bind_blob|sqlite3_bind()], 2790** [sqlite3_bind_parameter_count()], and 2791** [sqlite3_bind_parameter_index()]. 2792*/ 2793int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 2794 2795/* 2796** CAPI3REF: Reset All Bindings On A Prepared Statement 2797** 2798** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 2799** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 2800** ^Use this routine to reset all host parameters to NULL. 2801*/ 2802int sqlite3_clear_bindings(sqlite3_stmt*); 2803 2804/* 2805** CAPI3REF: Number Of Columns In A Result Set 2806** 2807** ^Return the number of columns in the result set returned by the 2808** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 2809** statement that does not return data (for example an [UPDATE]). 2810*/ 2811int sqlite3_column_count(sqlite3_stmt *pStmt); 2812 2813/* 2814** CAPI3REF: Column Names In A Result Set 2815** 2816** ^These routines return the name assigned to a particular column 2817** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 2818** interface returns a pointer to a zero-terminated UTF-8 string 2819** and sqlite3_column_name16() returns a pointer to a zero-terminated 2820** UTF-16 string. ^The first parameter is the [prepared statement] 2821** that implements the [SELECT] statement. ^The second parameter is the 2822** column number. ^The leftmost column is number 0. 2823** 2824** ^The returned string pointer is valid until either the [prepared statement] 2825** is destroyed by [sqlite3_finalize()] or until the next call to 2826** sqlite3_column_name() or sqlite3_column_name16() on the same column. 2827** 2828** ^If sqlite3_malloc() fails during the processing of either routine 2829** (for example during a conversion from UTF-8 to UTF-16) then a 2830** NULL pointer is returned. 2831** 2832** ^The name of a result column is the value of the "AS" clause for 2833** that column, if there is an AS clause. If there is no AS clause 2834** then the name of the column is unspecified and may change from 2835** one release of SQLite to the next. 2836*/ 2837const char *sqlite3_column_name(sqlite3_stmt*, int N); 2838const void *sqlite3_column_name16(sqlite3_stmt*, int N); 2839 2840/* 2841** CAPI3REF: Source Of Data In A Query Result 2842** 2843** ^These routines provide a means to determine the database, table, and 2844** table column that is the origin of a particular result column in 2845** [SELECT] statement. 2846** ^The name of the database or table or column can be returned as 2847** either a UTF-8 or UTF-16 string. ^The _database_ routines return 2848** the database name, the _table_ routines return the table name, and 2849** the origin_ routines return the column name. 2850** ^The returned string is valid until the [prepared statement] is destroyed 2851** using [sqlite3_finalize()] or until the same information is requested 2852** again in a different encoding. 2853** 2854** ^The names returned are the original un-aliased names of the 2855** database, table, and column. 2856** 2857** ^The first argument to these interfaces is a [prepared statement]. 2858** ^These functions return information about the Nth result column returned by 2859** the statement, where N is the second function argument. 2860** ^The left-most column is column 0 for these routines. 2861** 2862** ^If the Nth column returned by the statement is an expression or 2863** subquery and is not a column value, then all of these functions return 2864** NULL. ^These routine might also return NULL if a memory allocation error 2865** occurs. ^Otherwise, they return the name of the attached database, table, 2866** or column that query result column was extracted from. 2867** 2868** ^As with all other SQLite APIs, those whose names end with "16" return 2869** UTF-16 encoded strings and the other functions return UTF-8. 2870** 2871** ^These APIs are only available if the library was compiled with the 2872** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 2873** 2874** If two or more threads call one or more of these routines against the same 2875** prepared statement and column at the same time then the results are 2876** undefined. 2877** 2878** If two or more threads call one or more 2879** [sqlite3_column_database_name | column metadata interfaces] 2880** for the same [prepared statement] and result column 2881** at the same time then the results are undefined. 2882*/ 2883const char *sqlite3_column_database_name(sqlite3_stmt*,int); 2884const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 2885const char *sqlite3_column_table_name(sqlite3_stmt*,int); 2886const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 2887const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 2888const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 2889 2890/* 2891** CAPI3REF: Declared Datatype Of A Query Result 2892** 2893** ^(The first parameter is a [prepared statement]. 2894** If this statement is a [SELECT] statement and the Nth column of the 2895** returned result set of that [SELECT] is a table column (not an 2896** expression or subquery) then the declared type of the table 2897** column is returned.)^ ^If the Nth column of the result set is an 2898** expression or subquery, then a NULL pointer is returned. 2899** ^The returned string is always UTF-8 encoded. 2900** 2901** ^(For example, given the database schema: 2902** 2903** CREATE TABLE t1(c1 VARIANT); 2904** 2905** and the following statement to be compiled: 2906** 2907** SELECT c1 + 1, c1 FROM t1; 2908** 2909** this routine would return the string "VARIANT" for the second result 2910** column (i==1), and a NULL pointer for the first result column (i==0).)^ 2911** 2912** ^SQLite uses dynamic run-time typing. ^So just because a column 2913** is declared to contain a particular type does not mean that the 2914** data stored in that column is of the declared type. SQLite is 2915** strongly typed, but the typing is dynamic not static. ^Type 2916** is associated with individual values, not with the containers 2917** used to hold those values. 2918*/ 2919const char *sqlite3_column_decltype(sqlite3_stmt*,int); 2920const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 2921 2922/* 2923** CAPI3REF: Evaluate An SQL Statement 2924** 2925** After a [prepared statement] has been prepared using either 2926** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 2927** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 2928** must be called one or more times to evaluate the statement. 2929** 2930** The details of the behavior of the sqlite3_step() interface depend 2931** on whether the statement was prepared using the newer "v2" interface 2932** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 2933** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 2934** new "v2" interface is recommended for new applications but the legacy 2935** interface will continue to be supported. 2936** 2937** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 2938** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 2939** ^With the "v2" interface, any of the other [result codes] or 2940** [extended result codes] might be returned as well. 2941** 2942** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 2943** database locks it needs to do its job. ^If the statement is a [COMMIT] 2944** or occurs outside of an explicit transaction, then you can retry the 2945** statement. If the statement is not a [COMMIT] and occurs within a 2946** explicit transaction then you should rollback the transaction before 2947** continuing. 2948** 2949** ^[SQLITE_DONE] means that the statement has finished executing 2950** successfully. sqlite3_step() should not be called again on this virtual 2951** machine without first calling [sqlite3_reset()] to reset the virtual 2952** machine back to its initial state. 2953** 2954** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 2955** is returned each time a new row of data is ready for processing by the 2956** caller. The values may be accessed using the [column access functions]. 2957** sqlite3_step() is called again to retrieve the next row of data. 2958** 2959** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 2960** violation) has occurred. sqlite3_step() should not be called again on 2961** the VM. More information may be found by calling [sqlite3_errmsg()]. 2962** ^With the legacy interface, a more specific error code (for example, 2963** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 2964** can be obtained by calling [sqlite3_reset()] on the 2965** [prepared statement]. ^In the "v2" interface, 2966** the more specific error code is returned directly by sqlite3_step(). 2967** 2968** [SQLITE_MISUSE] means that the this routine was called inappropriately. 2969** Perhaps it was called on a [prepared statement] that has 2970** already been [sqlite3_finalize | finalized] or on one that had 2971** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 2972** be the case that the same database connection is being used by two or 2973** more threads at the same moment in time. 2974** 2975** For all versions of SQLite up to and including 3.6.23.1, it was required 2976** after sqlite3_step() returned anything other than [SQLITE_ROW] that 2977** [sqlite3_reset()] be called before any subsequent invocation of 2978** sqlite3_step(). Failure to invoke [sqlite3_reset()] in this way would 2979** result in an [SQLITE_MISUSE] return from sqlite3_step(). But after 2980** version 3.6.23.1, sqlite3_step() began calling [sqlite3_reset()] 2981** automatically in this circumstance rather than returning [SQLITE_MISUSE]. 2982** 2983** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 2984** API always returns a generic error code, [SQLITE_ERROR], following any 2985** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 2986** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 2987** specific [error codes] that better describes the error. 2988** We admit that this is a goofy design. The problem has been fixed 2989** with the "v2" interface. If you prepare all of your SQL statements 2990** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 2991** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 2992** then the more specific [error codes] are returned directly 2993** by sqlite3_step(). The use of the "v2" interface is recommended. 2994*/ 2995int sqlite3_step(sqlite3_stmt*); 2996 2997/* 2998** CAPI3REF: Number of columns in a result set 2999** 3000** ^The sqlite3_data_count(P) the number of columns in the 3001** of the result set of [prepared statement] P. 3002*/ 3003int sqlite3_data_count(sqlite3_stmt *pStmt); 3004 3005/* 3006** CAPI3REF: Fundamental Datatypes 3007** KEYWORDS: SQLITE_TEXT 3008** 3009** ^(Every value in SQLite has one of five fundamental datatypes: 3010** 3011** <ul> 3012** <li> 64-bit signed integer 3013** <li> 64-bit IEEE floating point number 3014** <li> string 3015** <li> BLOB 3016** <li> NULL 3017** </ul>)^ 3018** 3019** These constants are codes for each of those types. 3020** 3021** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3022** for a completely different meaning. Software that links against both 3023** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3024** SQLITE_TEXT. 3025*/ 3026#define SQLITE_INTEGER 1 3027#define SQLITE_FLOAT 2 3028#define SQLITE_BLOB 4 3029#define SQLITE_NULL 5 3030#ifdef SQLITE_TEXT 3031# undef SQLITE_TEXT 3032#else 3033# define SQLITE_TEXT 3 3034#endif 3035#define SQLITE3_TEXT 3 3036 3037/* 3038** CAPI3REF: Result Values From A Query 3039** KEYWORDS: {column access functions} 3040** 3041** These routines form the "result set" interface. 3042** 3043** ^These routines return information about a single column of the current 3044** result row of a query. ^In every case the first argument is a pointer 3045** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3046** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3047** and the second argument is the index of the column for which information 3048** should be returned. ^The leftmost column of the result set has the index 0. 3049** ^The number of columns in the result can be determined using 3050** [sqlite3_column_count()]. 3051** 3052** If the SQL statement does not currently point to a valid row, or if the 3053** column index is out of range, the result is undefined. 3054** These routines may only be called when the most recent call to 3055** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3056** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3057** If any of these routines are called after [sqlite3_reset()] or 3058** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3059** something other than [SQLITE_ROW], the results are undefined. 3060** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3061** are called from a different thread while any of these routines 3062** are pending, then the results are undefined. 3063** 3064** ^The sqlite3_column_type() routine returns the 3065** [SQLITE_INTEGER | datatype code] for the initial data type 3066** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3067** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3068** returned by sqlite3_column_type() is only meaningful if no type 3069** conversions have occurred as described below. After a type conversion, 3070** the value returned by sqlite3_column_type() is undefined. Future 3071** versions of SQLite may change the behavior of sqlite3_column_type() 3072** following a type conversion. 3073** 3074** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3075** routine returns the number of bytes in that BLOB or string. 3076** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3077** the string to UTF-8 and then returns the number of bytes. 3078** ^If the result is a numeric value then sqlite3_column_bytes() uses 3079** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3080** the number of bytes in that string. 3081** ^The value returned does not include the zero terminator at the end 3082** of the string. ^For clarity: the value returned is the number of 3083** bytes in the string, not the number of characters. 3084** 3085** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3086** even empty strings, are always zero terminated. ^The return 3087** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary 3088** pointer, possibly even a NULL pointer. 3089** 3090** ^The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes() 3091** but leaves the result in UTF-16 in native byte order instead of UTF-8. 3092** ^The zero terminator is not included in this count. 3093** 3094** ^The object returned by [sqlite3_column_value()] is an 3095** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3096** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3097** If the [unprotected sqlite3_value] object returned by 3098** [sqlite3_column_value()] is used in any other way, including calls 3099** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3100** or [sqlite3_value_bytes()], then the behavior is undefined. 3101** 3102** These routines attempt to convert the value where appropriate. ^For 3103** example, if the internal representation is FLOAT and a text result 3104** is requested, [sqlite3_snprintf()] is used internally to perform the 3105** conversion automatically. ^(The following table details the conversions 3106** that are applied: 3107** 3108** <blockquote> 3109** <table border="1"> 3110** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3111** 3112** <tr><td> NULL <td> INTEGER <td> Result is 0 3113** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3114** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3115** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3116** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3117** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3118** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3119** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3120** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3121** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3122** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3123** <tr><td> TEXT <td> FLOAT <td> Use atof() 3124** <tr><td> TEXT <td> BLOB <td> No change 3125** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3126** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3127** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3128** </table> 3129** </blockquote>)^ 3130** 3131** The table above makes reference to standard C library functions atoi() 3132** and atof(). SQLite does not really use these functions. It has its 3133** own equivalent internal routines. The atoi() and atof() names are 3134** used in the table for brevity and because they are familiar to most 3135** C programmers. 3136** 3137** ^Note that when type conversions occur, pointers returned by prior 3138** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3139** sqlite3_column_text16() may be invalidated. 3140** ^(Type conversions and pointer invalidations might occur 3141** in the following cases: 3142** 3143** <ul> 3144** <li> The initial content is a BLOB and sqlite3_column_text() or 3145** sqlite3_column_text16() is called. A zero-terminator might 3146** need to be added to the string.</li> 3147** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3148** sqlite3_column_text16() is called. The content must be converted 3149** to UTF-16.</li> 3150** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3151** sqlite3_column_text() is called. The content must be converted 3152** to UTF-8.</li> 3153** </ul>)^ 3154** 3155** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3156** not invalidate a prior pointer, though of course the content of the buffer 3157** that the prior pointer points to will have been modified. Other kinds 3158** of conversion are done in place when it is possible, but sometimes they 3159** are not possible and in those cases prior pointers are invalidated. 3160** 3161** ^(The safest and easiest to remember policy is to invoke these routines 3162** in one of the following ways: 3163** 3164** <ul> 3165** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3166** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3167** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3168** </ul>)^ 3169** 3170** In other words, you should call sqlite3_column_text(), 3171** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3172** into the desired format, then invoke sqlite3_column_bytes() or 3173** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3174** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3175** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3176** with calls to sqlite3_column_bytes(). 3177** 3178** ^The pointers returned are valid until a type conversion occurs as 3179** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3180** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3181** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3182** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3183** [sqlite3_free()]. 3184** 3185** ^(If a memory allocation error occurs during the evaluation of any 3186** of these routines, a default value is returned. The default value 3187** is either the integer 0, the floating point number 0.0, or a NULL 3188** pointer. Subsequent calls to [sqlite3_errcode()] will return 3189** [SQLITE_NOMEM].)^ 3190*/ 3191const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3192int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3193int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3194double sqlite3_column_double(sqlite3_stmt*, int iCol); 3195int sqlite3_column_int(sqlite3_stmt*, int iCol); 3196sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3197const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3198const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3199int sqlite3_column_type(sqlite3_stmt*, int iCol); 3200sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3201 3202/* 3203** CAPI3REF: Destroy A Prepared Statement Object 3204** 3205** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3206** ^If the statement was executed successfully or not executed at all, then 3207** SQLITE_OK is returned. ^If execution of the statement failed then an 3208** [error code] or [extended error code] is returned. 3209** 3210** ^This routine can be called at any point during the execution of the 3211** [prepared statement]. ^If the virtual machine has not 3212** completed execution when this routine is called, that is like 3213** encountering an error or an [sqlite3_interrupt | interrupt]. 3214** ^Incomplete updates may be rolled back and transactions canceled, 3215** depending on the circumstances, and the 3216** [error code] returned will be [SQLITE_ABORT]. 3217*/ 3218int sqlite3_finalize(sqlite3_stmt *pStmt); 3219 3220/* 3221** CAPI3REF: Reset A Prepared Statement Object 3222** 3223** The sqlite3_reset() function is called to reset a [prepared statement] 3224** object back to its initial state, ready to be re-executed. 3225** ^Any SQL statement variables that had values bound to them using 3226** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3227** Use [sqlite3_clear_bindings()] to reset the bindings. 3228** 3229** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3230** back to the beginning of its program. 3231** 3232** ^If the most recent call to [sqlite3_step(S)] for the 3233** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3234** or if [sqlite3_step(S)] has never before been called on S, 3235** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3236** 3237** ^If the most recent call to [sqlite3_step(S)] for the 3238** [prepared statement] S indicated an error, then 3239** [sqlite3_reset(S)] returns an appropriate [error code]. 3240** 3241** ^The [sqlite3_reset(S)] interface does not change the values 3242** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3243*/ 3244int sqlite3_reset(sqlite3_stmt *pStmt); 3245 3246/* 3247** CAPI3REF: Create Or Redefine SQL Functions 3248** KEYWORDS: {function creation routines} 3249** KEYWORDS: {application-defined SQL function} 3250** KEYWORDS: {application-defined SQL functions} 3251** 3252** ^These two functions (collectively known as "function creation routines") 3253** are used to add SQL functions or aggregates or to redefine the behavior 3254** of existing SQL functions or aggregates. The only difference between the 3255** two is that the second parameter, the name of the (scalar) function or 3256** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16 3257** for sqlite3_create_function16(). 3258** 3259** ^The first parameter is the [database connection] to which the SQL 3260** function is to be added. ^If an application uses more than one database 3261** connection then application-defined SQL functions must be added 3262** to each database connection separately. 3263** 3264** The second parameter is the name of the SQL function to be created or 3265** redefined. ^The length of the name is limited to 255 bytes, exclusive of 3266** the zero-terminator. Note that the name length limit is in bytes, not 3267** characters. ^Any attempt to create a function with a longer name 3268** will result in [SQLITE_ERROR] being returned. 3269** 3270** ^The third parameter (nArg) 3271** is the number of arguments that the SQL function or 3272** aggregate takes. ^If this parameter is -1, then the SQL function or 3273** aggregate may take any number of arguments between 0 and the limit 3274** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3275** parameter is less than -1 or greater than 127 then the behavior is 3276** undefined. 3277** 3278** The fourth parameter, eTextRep, specifies what 3279** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3280** its parameters. Any SQL function implementation should be able to work 3281** work with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3282** more efficient with one encoding than another. ^An application may 3283** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3284** times with the same function but with different values of eTextRep. 3285** ^When multiple implementations of the same function are available, SQLite 3286** will pick the one that involves the least amount of data conversion. 3287** If there is only a single implementation which does not care what text 3288** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3289** 3290** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3291** function can gain access to this pointer using [sqlite3_user_data()].)^ 3292** 3293** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are 3294** pointers to C-language functions that implement the SQL function or 3295** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3296** callback only; NULL pointers should be passed as the xStep and xFinal 3297** parameters. ^An aggregate SQL function requires an implementation of xStep 3298** and xFinal and NULL should be passed for xFunc. ^To delete an existing 3299** SQL function or aggregate, pass NULL for all three function callbacks. 3300** 3301** ^It is permitted to register multiple implementations of the same 3302** functions with the same name but with either differing numbers of 3303** arguments or differing preferred text encodings. ^SQLite will use 3304** the implementation that most closely matches the way in which the 3305** SQL function is used. ^A function implementation with a non-negative 3306** nArg parameter is a better match than a function implementation with 3307** a negative nArg. ^A function where the preferred text encoding 3308** matches the database encoding is a better 3309** match than a function where the encoding is different. 3310** ^A function where the encoding difference is between UTF16le and UTF16be 3311** is a closer match than a function where the encoding difference is 3312** between UTF8 and UTF16. 3313** 3314** ^Built-in functions may be overloaded by new application-defined functions. 3315** ^The first application-defined function with a given name overrides all 3316** built-in functions in the same [database connection] with the same name. 3317** ^Subsequent application-defined functions of the same name only override 3318** prior application-defined functions that are an exact match for the 3319** number of parameters and preferred encoding. 3320** 3321** ^An application-defined function is permitted to call other 3322** SQLite interfaces. However, such calls must not 3323** close the database connection nor finalize or reset the prepared 3324** statement in which the function is running. 3325*/ 3326int sqlite3_create_function( 3327 sqlite3 *db, 3328 const char *zFunctionName, 3329 int nArg, 3330 int eTextRep, 3331 void *pApp, 3332 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3333 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3334 void (*xFinal)(sqlite3_context*) 3335); 3336int sqlite3_create_function16( 3337 sqlite3 *db, 3338 const void *zFunctionName, 3339 int nArg, 3340 int eTextRep, 3341 void *pApp, 3342 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3343 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3344 void (*xFinal)(sqlite3_context*) 3345); 3346 3347/* 3348** CAPI3REF: Text Encodings 3349** 3350** These constant define integer codes that represent the various 3351** text encodings supported by SQLite. 3352*/ 3353#define SQLITE_UTF8 1 3354#define SQLITE_UTF16LE 2 3355#define SQLITE_UTF16BE 3 3356#define SQLITE_UTF16 4 /* Use native byte order */ 3357#define SQLITE_ANY 5 /* sqlite3_create_function only */ 3358#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3359 3360/* 3361** CAPI3REF: Deprecated Functions 3362** DEPRECATED 3363** 3364** These functions are [deprecated]. In order to maintain 3365** backwards compatibility with older code, these functions continue 3366** to be supported. However, new applications should avoid 3367** the use of these functions. To help encourage people to avoid 3368** using these functions, we are not going to tell you what they do. 3369*/ 3370#ifndef SQLITE_OMIT_DEPRECATED 3371SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3372SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3373SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3374SQLITE_DEPRECATED int sqlite3_global_recover(void); 3375SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3376SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3377#endif 3378 3379/* 3380** CAPI3REF: Obtaining SQL Function Parameter Values 3381** 3382** The C-language implementation of SQL functions and aggregates uses 3383** this set of interface routines to access the parameter values on 3384** the function or aggregate. 3385** 3386** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3387** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3388** define callbacks that implement the SQL functions and aggregates. 3389** The 4th parameter to these callbacks is an array of pointers to 3390** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3391** each parameter to the SQL function. These routines are used to 3392** extract values from the [sqlite3_value] objects. 3393** 3394** These routines work only with [protected sqlite3_value] objects. 3395** Any attempt to use these routines on an [unprotected sqlite3_value] 3396** object results in undefined behavior. 3397** 3398** ^These routines work just like the corresponding [column access functions] 3399** except that these routines take a single [protected sqlite3_value] object 3400** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3401** 3402** ^The sqlite3_value_text16() interface extracts a UTF-16 string 3403** in the native byte-order of the host machine. ^The 3404** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3405** extract UTF-16 strings as big-endian and little-endian respectively. 3406** 3407** ^(The sqlite3_value_numeric_type() interface attempts to apply 3408** numeric affinity to the value. This means that an attempt is 3409** made to convert the value to an integer or floating point. If 3410** such a conversion is possible without loss of information (in other 3411** words, if the value is a string that looks like a number) 3412** then the conversion is performed. Otherwise no conversion occurs. 3413** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 3414** 3415** Please pay particular attention to the fact that the pointer returned 3416** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3417** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3418** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3419** or [sqlite3_value_text16()]. 3420** 3421** These routines must be called from the same thread as 3422** the SQL function that supplied the [sqlite3_value*] parameters. 3423*/ 3424const void *sqlite3_value_blob(sqlite3_value*); 3425int sqlite3_value_bytes(sqlite3_value*); 3426int sqlite3_value_bytes16(sqlite3_value*); 3427double sqlite3_value_double(sqlite3_value*); 3428int sqlite3_value_int(sqlite3_value*); 3429sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3430const unsigned char *sqlite3_value_text(sqlite3_value*); 3431const void *sqlite3_value_text16(sqlite3_value*); 3432const void *sqlite3_value_text16le(sqlite3_value*); 3433const void *sqlite3_value_text16be(sqlite3_value*); 3434int sqlite3_value_type(sqlite3_value*); 3435int sqlite3_value_numeric_type(sqlite3_value*); 3436 3437/* 3438** CAPI3REF: Obtain Aggregate Function Context 3439** 3440** Implementions of aggregate SQL functions use this 3441** routine to allocate memory for storing their state. 3442** 3443** ^The first time the sqlite3_aggregate_context(C,N) routine is called 3444** for a particular aggregate function, SQLite 3445** allocates N of memory, zeroes out that memory, and returns a pointer 3446** to the new memory. ^On second and subsequent calls to 3447** sqlite3_aggregate_context() for the same aggregate function instance, 3448** the same buffer is returned. Sqlite3_aggregate_context() is normally 3449** called once for each invocation of the xStep callback and then one 3450** last time when the xFinal callback is invoked. ^(When no rows match 3451** an aggregate query, the xStep() callback of the aggregate function 3452** implementation is never called and xFinal() is called exactly once. 3453** In those cases, sqlite3_aggregate_context() might be called for the 3454** first time from within xFinal().)^ 3455** 3456** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is 3457** less than or equal to zero or if a memory allocate error occurs. 3458** 3459** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 3460** determined by the N parameter on first successful call. Changing the 3461** value of N in subsequent call to sqlite3_aggregate_context() within 3462** the same aggregate function instance will not resize the memory 3463** allocation.)^ 3464** 3465** ^SQLite automatically frees the memory allocated by 3466** sqlite3_aggregate_context() when the aggregate query concludes. 3467** 3468** The first parameter must be a copy of the 3469** [sqlite3_context | SQL function context] that is the first parameter 3470** to the xStep or xFinal callback routine that implements the aggregate 3471** function. 3472** 3473** This routine must be called from the same thread in which 3474** the aggregate SQL function is running. 3475*/ 3476void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 3477 3478/* 3479** CAPI3REF: User Data For Functions 3480** 3481** ^The sqlite3_user_data() interface returns a copy of 3482** the pointer that was the pUserData parameter (the 5th parameter) 3483** of the [sqlite3_create_function()] 3484** and [sqlite3_create_function16()] routines that originally 3485** registered the application defined function. 3486** 3487** This routine must be called from the same thread in which 3488** the application-defined function is running. 3489*/ 3490void *sqlite3_user_data(sqlite3_context*); 3491 3492/* 3493** CAPI3REF: Database Connection For Functions 3494** 3495** ^The sqlite3_context_db_handle() interface returns a copy of 3496** the pointer to the [database connection] (the 1st parameter) 3497** of the [sqlite3_create_function()] 3498** and [sqlite3_create_function16()] routines that originally 3499** registered the application defined function. 3500*/ 3501sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 3502 3503/* 3504** CAPI3REF: Function Auxiliary Data 3505** 3506** The following two functions may be used by scalar SQL functions to 3507** associate metadata with argument values. If the same value is passed to 3508** multiple invocations of the same SQL function during query execution, under 3509** some circumstances the associated metadata may be preserved. This may 3510** be used, for example, to add a regular-expression matching scalar 3511** function. The compiled version of the regular expression is stored as 3512** metadata associated with the SQL value passed as the regular expression 3513** pattern. The compiled regular expression can be reused on multiple 3514** invocations of the same function so that the original pattern string 3515** does not need to be recompiled on each invocation. 3516** 3517** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 3518** associated by the sqlite3_set_auxdata() function with the Nth argument 3519** value to the application-defined function. ^If no metadata has been ever 3520** been set for the Nth argument of the function, or if the corresponding 3521** function parameter has changed since the meta-data was set, 3522** then sqlite3_get_auxdata() returns a NULL pointer. 3523** 3524** ^The sqlite3_set_auxdata() interface saves the metadata 3525** pointed to by its 3rd parameter as the metadata for the N-th 3526** argument of the application-defined function. Subsequent 3527** calls to sqlite3_get_auxdata() might return this data, if it has 3528** not been destroyed. 3529** ^If it is not NULL, SQLite will invoke the destructor 3530** function given by the 4th parameter to sqlite3_set_auxdata() on 3531** the metadata when the corresponding function parameter changes 3532** or when the SQL statement completes, whichever comes first. 3533** 3534** SQLite is free to call the destructor and drop metadata on any 3535** parameter of any function at any time. ^The only guarantee is that 3536** the destructor will be called before the metadata is dropped. 3537** 3538** ^(In practice, metadata is preserved between function calls for 3539** expressions that are constant at compile time. This includes literal 3540** values and [parameters].)^ 3541** 3542** These routines must be called from the same thread in which 3543** the SQL function is running. 3544*/ 3545void *sqlite3_get_auxdata(sqlite3_context*, int N); 3546void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 3547 3548 3549/* 3550** CAPI3REF: Constants Defining Special Destructor Behavior 3551** 3552** These are special values for the destructor that is passed in as the 3553** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 3554** argument is SQLITE_STATIC, it means that the content pointer is constant 3555** and will never change. It does not need to be destroyed. ^The 3556** SQLITE_TRANSIENT value means that the content will likely change in 3557** the near future and that SQLite should make its own private copy of 3558** the content before returning. 3559** 3560** The typedef is necessary to work around problems in certain 3561** C++ compilers. See ticket #2191. 3562*/ 3563typedef void (*sqlite3_destructor_type)(void*); 3564#define SQLITE_STATIC ((sqlite3_destructor_type)0) 3565#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 3566 3567/* 3568** CAPI3REF: Setting The Result Of An SQL Function 3569** 3570** These routines are used by the xFunc or xFinal callbacks that 3571** implement SQL functions and aggregates. See 3572** [sqlite3_create_function()] and [sqlite3_create_function16()] 3573** for additional information. 3574** 3575** These functions work very much like the [parameter binding] family of 3576** functions used to bind values to host parameters in prepared statements. 3577** Refer to the [SQL parameter] documentation for additional information. 3578** 3579** ^The sqlite3_result_blob() interface sets the result from 3580** an application-defined function to be the BLOB whose content is pointed 3581** to by the second parameter and which is N bytes long where N is the 3582** third parameter. 3583** 3584** ^The sqlite3_result_zeroblob() interfaces set the result of 3585** the application-defined function to be a BLOB containing all zero 3586** bytes and N bytes in size, where N is the value of the 2nd parameter. 3587** 3588** ^The sqlite3_result_double() interface sets the result from 3589** an application-defined function to be a floating point value specified 3590** by its 2nd argument. 3591** 3592** ^The sqlite3_result_error() and sqlite3_result_error16() functions 3593** cause the implemented SQL function to throw an exception. 3594** ^SQLite uses the string pointed to by the 3595** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 3596** as the text of an error message. ^SQLite interprets the error 3597** message string from sqlite3_result_error() as UTF-8. ^SQLite 3598** interprets the string from sqlite3_result_error16() as UTF-16 in native 3599** byte order. ^If the third parameter to sqlite3_result_error() 3600** or sqlite3_result_error16() is negative then SQLite takes as the error 3601** message all text up through the first zero character. 3602** ^If the third parameter to sqlite3_result_error() or 3603** sqlite3_result_error16() is non-negative then SQLite takes that many 3604** bytes (not characters) from the 2nd parameter as the error message. 3605** ^The sqlite3_result_error() and sqlite3_result_error16() 3606** routines make a private copy of the error message text before 3607** they return. Hence, the calling function can deallocate or 3608** modify the text after they return without harm. 3609** ^The sqlite3_result_error_code() function changes the error code 3610** returned by SQLite as a result of an error in a function. ^By default, 3611** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 3612** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 3613** 3614** ^The sqlite3_result_toobig() interface causes SQLite to throw an error 3615** indicating that a string or BLOB is too long to represent. 3616** 3617** ^The sqlite3_result_nomem() interface causes SQLite to throw an error 3618** indicating that a memory allocation failed. 3619** 3620** ^The sqlite3_result_int() interface sets the return value 3621** of the application-defined function to be the 32-bit signed integer 3622** value given in the 2nd argument. 3623** ^The sqlite3_result_int64() interface sets the return value 3624** of the application-defined function to be the 64-bit signed integer 3625** value given in the 2nd argument. 3626** 3627** ^The sqlite3_result_null() interface sets the return value 3628** of the application-defined function to be NULL. 3629** 3630** ^The sqlite3_result_text(), sqlite3_result_text16(), 3631** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 3632** set the return value of the application-defined function to be 3633** a text string which is represented as UTF-8, UTF-16 native byte order, 3634** UTF-16 little endian, or UTF-16 big endian, respectively. 3635** ^SQLite takes the text result from the application from 3636** the 2nd parameter of the sqlite3_result_text* interfaces. 3637** ^If the 3rd parameter to the sqlite3_result_text* interfaces 3638** is negative, then SQLite takes result text from the 2nd parameter 3639** through the first zero character. 3640** ^If the 3rd parameter to the sqlite3_result_text* interfaces 3641** is non-negative, then as many bytes (not characters) of the text 3642** pointed to by the 2nd parameter are taken as the application-defined 3643** function result. 3644** ^If the 4th parameter to the sqlite3_result_text* interfaces 3645** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 3646** function as the destructor on the text or BLOB result when it has 3647** finished using that result. 3648** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 3649** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 3650** assumes that the text or BLOB result is in constant space and does not 3651** copy the content of the parameter nor call a destructor on the content 3652** when it has finished using that result. 3653** ^If the 4th parameter to the sqlite3_result_text* interfaces 3654** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 3655** then SQLite makes a copy of the result into space obtained from 3656** from [sqlite3_malloc()] before it returns. 3657** 3658** ^The sqlite3_result_value() interface sets the result of 3659** the application-defined function to be a copy the 3660** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 3661** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 3662** so that the [sqlite3_value] specified in the parameter may change or 3663** be deallocated after sqlite3_result_value() returns without harm. 3664** ^A [protected sqlite3_value] object may always be used where an 3665** [unprotected sqlite3_value] object is required, so either 3666** kind of [sqlite3_value] object can be used with this interface. 3667** 3668** If these routines are called from within the different thread 3669** than the one containing the application-defined function that received 3670** the [sqlite3_context] pointer, the results are undefined. 3671*/ 3672void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 3673void sqlite3_result_double(sqlite3_context*, double); 3674void sqlite3_result_error(sqlite3_context*, const char*, int); 3675void sqlite3_result_error16(sqlite3_context*, const void*, int); 3676void sqlite3_result_error_toobig(sqlite3_context*); 3677void sqlite3_result_error_nomem(sqlite3_context*); 3678void sqlite3_result_error_code(sqlite3_context*, int); 3679void sqlite3_result_int(sqlite3_context*, int); 3680void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 3681void sqlite3_result_null(sqlite3_context*); 3682void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 3683void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 3684void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 3685void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 3686void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 3687void sqlite3_result_zeroblob(sqlite3_context*, int n); 3688 3689/* 3690** CAPI3REF: Define New Collating Sequences 3691** 3692** These functions are used to add new collation sequences to the 3693** [database connection] specified as the first argument. 3694** 3695** ^The name of the new collation sequence is specified as a UTF-8 string 3696** for sqlite3_create_collation() and sqlite3_create_collation_v2() 3697** and a UTF-16 string for sqlite3_create_collation16(). ^In all cases 3698** the name is passed as the second function argument. 3699** 3700** ^The third argument may be one of the constants [SQLITE_UTF8], 3701** [SQLITE_UTF16LE], or [SQLITE_UTF16BE], indicating that the user-supplied 3702** routine expects to be passed pointers to strings encoded using UTF-8, 3703** UTF-16 little-endian, or UTF-16 big-endian, respectively. ^The 3704** third argument might also be [SQLITE_UTF16] to indicate that the routine 3705** expects pointers to be UTF-16 strings in the native byte order, or the 3706** argument can be [SQLITE_UTF16_ALIGNED] if the 3707** the routine expects pointers to 16-bit word aligned strings 3708** of UTF-16 in the native byte order. 3709** 3710** A pointer to the user supplied routine must be passed as the fifth 3711** argument. ^If it is NULL, this is the same as deleting the collation 3712** sequence (so that SQLite cannot call it anymore). 3713** ^Each time the application supplied function is invoked, it is passed 3714** as its first parameter a copy of the void* passed as the fourth argument 3715** to sqlite3_create_collation() or sqlite3_create_collation16(). 3716** 3717** ^The remaining arguments to the application-supplied routine are two strings, 3718** each represented by a (length, data) pair and encoded in the encoding 3719** that was passed as the third argument when the collation sequence was 3720** registered. The application defined collation routine should 3721** return negative, zero or positive if the first string is less than, 3722** equal to, or greater than the second string. i.e. (STRING1 - STRING2). 3723** 3724** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 3725** except that it takes an extra argument which is a destructor for 3726** the collation. ^The destructor is called when the collation is 3727** destroyed and is passed a copy of the fourth parameter void* pointer 3728** of the sqlite3_create_collation_v2(). 3729** ^Collations are destroyed when they are overridden by later calls to the 3730** collation creation functions or when the [database connection] is closed 3731** using [sqlite3_close()]. 3732** 3733** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 3734*/ 3735int sqlite3_create_collation( 3736 sqlite3*, 3737 const char *zName, 3738 int eTextRep, 3739 void*, 3740 int(*xCompare)(void*,int,const void*,int,const void*) 3741); 3742int sqlite3_create_collation_v2( 3743 sqlite3*, 3744 const char *zName, 3745 int eTextRep, 3746 void*, 3747 int(*xCompare)(void*,int,const void*,int,const void*), 3748 void(*xDestroy)(void*) 3749); 3750int sqlite3_create_collation16( 3751 sqlite3*, 3752 const void *zName, 3753 int eTextRep, 3754 void*, 3755 int(*xCompare)(void*,int,const void*,int,const void*) 3756); 3757 3758/* 3759** CAPI3REF: Collation Needed Callbacks 3760** 3761** ^To avoid having to register all collation sequences before a database 3762** can be used, a single callback function may be registered with the 3763** [database connection] to be invoked whenever an undefined collation 3764** sequence is required. 3765** 3766** ^If the function is registered using the sqlite3_collation_needed() API, 3767** then it is passed the names of undefined collation sequences as strings 3768** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 3769** the names are passed as UTF-16 in machine native byte order. 3770** ^A call to either function replaces the existing collation-needed callback. 3771** 3772** ^(When the callback is invoked, the first argument passed is a copy 3773** of the second argument to sqlite3_collation_needed() or 3774** sqlite3_collation_needed16(). The second argument is the database 3775** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 3776** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 3777** sequence function required. The fourth parameter is the name of the 3778** required collation sequence.)^ 3779** 3780** The callback function should register the desired collation using 3781** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 3782** [sqlite3_create_collation_v2()]. 3783*/ 3784int sqlite3_collation_needed( 3785 sqlite3*, 3786 void*, 3787 void(*)(void*,sqlite3*,int eTextRep,const char*) 3788); 3789int sqlite3_collation_needed16( 3790 sqlite3*, 3791 void*, 3792 void(*)(void*,sqlite3*,int eTextRep,const void*) 3793); 3794 3795#ifdef SQLITE_HAS_CODEC 3796/* 3797** Specify the key for an encrypted database. This routine should be 3798** called right after sqlite3_open(). 3799** 3800** The code to implement this API is not available in the public release 3801** of SQLite. 3802*/ 3803int sqlite3_key( 3804 sqlite3 *db, /* Database to be rekeyed */ 3805 const void *pKey, int nKey /* The key */ 3806); 3807 3808/* 3809** Change the key on an open database. If the current database is not 3810** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 3811** database is decrypted. 3812** 3813** The code to implement this API is not available in the public release 3814** of SQLite. 3815*/ 3816int sqlite3_rekey( 3817 sqlite3 *db, /* Database to be rekeyed */ 3818 const void *pKey, int nKey /* The new key */ 3819); 3820 3821/* 3822** Specify the activation key for a SEE database. Unless 3823** activated, none of the SEE routines will work. 3824*/ 3825void sqlite3_activate_see( 3826 const char *zPassPhrase /* Activation phrase */ 3827); 3828#endif 3829 3830#ifdef SQLITE_ENABLE_CEROD 3831/* 3832** Specify the activation key for a CEROD database. Unless 3833** activated, none of the CEROD routines will work. 3834*/ 3835void sqlite3_activate_cerod( 3836 const char *zPassPhrase /* Activation phrase */ 3837); 3838#endif 3839 3840/* 3841** CAPI3REF: Suspend Execution For A Short Time 3842** 3843** ^The sqlite3_sleep() function causes the current thread to suspend execution 3844** for at least a number of milliseconds specified in its parameter. 3845** 3846** ^If the operating system does not support sleep requests with 3847** millisecond time resolution, then the time will be rounded up to 3848** the nearest second. ^The number of milliseconds of sleep actually 3849** requested from the operating system is returned. 3850** 3851** ^SQLite implements this interface by calling the xSleep() 3852** method of the default [sqlite3_vfs] object. 3853*/ 3854int sqlite3_sleep(int); 3855 3856/* 3857** CAPI3REF: Name Of The Folder Holding Temporary Files 3858** 3859** ^(If this global variable is made to point to a string which is 3860** the name of a folder (a.k.a. directory), then all temporary files 3861** created by SQLite when using a built-in [sqlite3_vfs | VFS] 3862** will be placed in that directory.)^ ^If this variable 3863** is a NULL pointer, then SQLite performs a search for an appropriate 3864** temporary file directory. 3865** 3866** It is not safe to read or modify this variable in more than one 3867** thread at a time. It is not safe to read or modify this variable 3868** if a [database connection] is being used at the same time in a separate 3869** thread. 3870** It is intended that this variable be set once 3871** as part of process initialization and before any SQLite interface 3872** routines have been called and that this variable remain unchanged 3873** thereafter. 3874** 3875** ^The [temp_store_directory pragma] may modify this variable and cause 3876** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 3877** the [temp_store_directory pragma] always assumes that any string 3878** that this variable points to is held in memory obtained from 3879** [sqlite3_malloc] and the pragma may attempt to free that memory 3880** using [sqlite3_free]. 3881** Hence, if this variable is modified directly, either it should be 3882** made NULL or made to point to memory obtained from [sqlite3_malloc] 3883** or else the use of the [temp_store_directory pragma] should be avoided. 3884*/ 3885SQLITE_EXTERN char *sqlite3_temp_directory; 3886 3887/* 3888** CAPI3REF: Test For Auto-Commit Mode 3889** KEYWORDS: {autocommit mode} 3890** 3891** ^The sqlite3_get_autocommit() interface returns non-zero or 3892** zero if the given database connection is or is not in autocommit mode, 3893** respectively. ^Autocommit mode is on by default. 3894** ^Autocommit mode is disabled by a [BEGIN] statement. 3895** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 3896** 3897** If certain kinds of errors occur on a statement within a multi-statement 3898** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 3899** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 3900** transaction might be rolled back automatically. The only way to 3901** find out whether SQLite automatically rolled back the transaction after 3902** an error is to use this function. 3903** 3904** If another thread changes the autocommit status of the database 3905** connection while this routine is running, then the return value 3906** is undefined. 3907*/ 3908int sqlite3_get_autocommit(sqlite3*); 3909 3910/* 3911** CAPI3REF: Find The Database Handle Of A Prepared Statement 3912** 3913** ^The sqlite3_db_handle interface returns the [database connection] handle 3914** to which a [prepared statement] belongs. ^The [database connection] 3915** returned by sqlite3_db_handle is the same [database connection] 3916** that was the first argument 3917** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 3918** create the statement in the first place. 3919*/ 3920sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 3921 3922/* 3923** CAPI3REF: Find the next prepared statement 3924** 3925** ^This interface returns a pointer to the next [prepared statement] after 3926** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 3927** then this interface returns a pointer to the first prepared statement 3928** associated with the database connection pDb. ^If no prepared statement 3929** satisfies the conditions of this routine, it returns NULL. 3930** 3931** The [database connection] pointer D in a call to 3932** [sqlite3_next_stmt(D,S)] must refer to an open database 3933** connection and in particular must not be a NULL pointer. 3934*/ 3935sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 3936 3937/* 3938** CAPI3REF: Commit And Rollback Notification Callbacks 3939** 3940** ^The sqlite3_commit_hook() interface registers a callback 3941** function to be invoked whenever a transaction is [COMMIT | committed]. 3942** ^Any callback set by a previous call to sqlite3_commit_hook() 3943** for the same database connection is overridden. 3944** ^The sqlite3_rollback_hook() interface registers a callback 3945** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 3946** ^Any callback set by a previous call to sqlite3_rollback_hook() 3947** for the same database connection is overridden. 3948** ^The pArg argument is passed through to the callback. 3949** ^If the callback on a commit hook function returns non-zero, 3950** then the commit is converted into a rollback. 3951** 3952** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 3953** return the P argument from the previous call of the same function 3954** on the same [database connection] D, or NULL for 3955** the first call for each function on D. 3956** 3957** The callback implementation must not do anything that will modify 3958** the database connection that invoked the callback. Any actions 3959** to modify the database connection must be deferred until after the 3960** completion of the [sqlite3_step()] call that triggered the commit 3961** or rollback hook in the first place. 3962** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3963** database connections for the meaning of "modify" in this paragraph. 3964** 3965** ^Registering a NULL function disables the callback. 3966** 3967** ^When the commit hook callback routine returns zero, the [COMMIT] 3968** operation is allowed to continue normally. ^If the commit hook 3969** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 3970** ^The rollback hook is invoked on a rollback that results from a commit 3971** hook returning non-zero, just as it would be with any other rollback. 3972** 3973** ^For the purposes of this API, a transaction is said to have been 3974** rolled back if an explicit "ROLLBACK" statement is executed, or 3975** an error or constraint causes an implicit rollback to occur. 3976** ^The rollback callback is not invoked if a transaction is 3977** automatically rolled back because the database connection is closed. 3978** 3979** See also the [sqlite3_update_hook()] interface. 3980*/ 3981void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 3982void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 3983 3984/* 3985** CAPI3REF: Data Change Notification Callbacks 3986** 3987** ^The sqlite3_update_hook() interface registers a callback function 3988** with the [database connection] identified by the first argument 3989** to be invoked whenever a row is updated, inserted or deleted. 3990** ^Any callback set by a previous call to this function 3991** for the same database connection is overridden. 3992** 3993** ^The second argument is a pointer to the function to invoke when a 3994** row is updated, inserted or deleted. 3995** ^The first argument to the callback is a copy of the third argument 3996** to sqlite3_update_hook(). 3997** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 3998** or [SQLITE_UPDATE], depending on the operation that caused the callback 3999** to be invoked. 4000** ^The third and fourth arguments to the callback contain pointers to the 4001** database and table name containing the affected row. 4002** ^The final callback parameter is the [rowid] of the row. 4003** ^In the case of an update, this is the [rowid] after the update takes place. 4004** 4005** ^(The update hook is not invoked when internal system tables are 4006** modified (i.e. sqlite_master and sqlite_sequence).)^ 4007** 4008** ^In the current implementation, the update hook 4009** is not invoked when duplication rows are deleted because of an 4010** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 4011** invoked when rows are deleted using the [truncate optimization]. 4012** The exceptions defined in this paragraph might change in a future 4013** release of SQLite. 4014** 4015** The update hook implementation must not do anything that will modify 4016** the database connection that invoked the update hook. Any actions 4017** to modify the database connection must be deferred until after the 4018** completion of the [sqlite3_step()] call that triggered the update hook. 4019** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4020** database connections for the meaning of "modify" in this paragraph. 4021** 4022** ^The sqlite3_update_hook(D,C,P) function 4023** returns the P argument from the previous call 4024** on the same [database connection] D, or NULL for 4025** the first call on D. 4026** 4027** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4028** interfaces. 4029*/ 4030void *sqlite3_update_hook( 4031 sqlite3*, 4032 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4033 void* 4034); 4035 4036/* 4037** CAPI3REF: Enable Or Disable Shared Pager Cache 4038** KEYWORDS: {shared cache} 4039** 4040** ^(This routine enables or disables the sharing of the database cache 4041** and schema data structures between [database connection | connections] 4042** to the same database. Sharing is enabled if the argument is true 4043** and disabled if the argument is false.)^ 4044** 4045** ^Cache sharing is enabled and disabled for an entire process. 4046** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4047** sharing was enabled or disabled for each thread separately. 4048** 4049** ^(The cache sharing mode set by this interface effects all subsequent 4050** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4051** Existing database connections continue use the sharing mode 4052** that was in effect at the time they were opened.)^ 4053** 4054** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4055** successfully. An [error code] is returned otherwise.)^ 4056** 4057** ^Shared cache is disabled by default. But this might change in 4058** future releases of SQLite. Applications that care about shared 4059** cache setting should set it explicitly. 4060** 4061** See Also: [SQLite Shared-Cache Mode] 4062*/ 4063int sqlite3_enable_shared_cache(int); 4064 4065/* 4066** CAPI3REF: Attempt To Free Heap Memory 4067** 4068** ^The sqlite3_release_memory() interface attempts to free N bytes 4069** of heap memory by deallocating non-essential memory allocations 4070** held by the database library. Memory used to cache database 4071** pages to improve performance is an example of non-essential memory. 4072** ^sqlite3_release_memory() returns the number of bytes actually freed, 4073** which might be more or less than the amount requested. 4074*/ 4075int sqlite3_release_memory(int); 4076 4077/* 4078** CAPI3REF: Impose A Limit On Heap Size 4079** 4080** ^The sqlite3_soft_heap_limit() interface places a "soft" limit 4081** on the amount of heap memory that may be allocated by SQLite. 4082** ^If an internal allocation is requested that would exceed the 4083** soft heap limit, [sqlite3_release_memory()] is invoked one or 4084** more times to free up some space before the allocation is performed. 4085** 4086** ^The limit is called "soft" because if [sqlite3_release_memory()] 4087** cannot free sufficient memory to prevent the limit from being exceeded, 4088** the memory is allocated anyway and the current operation proceeds. 4089** 4090** ^A negative or zero value for N means that there is no soft heap limit and 4091** [sqlite3_release_memory()] will only be called when memory is exhausted. 4092** ^The default value for the soft heap limit is zero. 4093** 4094** ^(SQLite makes a best effort to honor the soft heap limit. 4095** But if the soft heap limit cannot be honored, execution will 4096** continue without error or notification.)^ This is why the limit is 4097** called a "soft" limit. It is advisory only. 4098** 4099** Prior to SQLite version 3.5.0, this routine only constrained the memory 4100** allocated by a single thread - the same thread in which this routine 4101** runs. Beginning with SQLite version 3.5.0, the soft heap limit is 4102** applied to all threads. The value specified for the soft heap limit 4103** is an upper bound on the total memory allocation for all threads. In 4104** version 3.5.0 there is no mechanism for limiting the heap usage for 4105** individual threads. 4106*/ 4107void sqlite3_soft_heap_limit(int); 4108 4109/* 4110** CAPI3REF: Extract Metadata About A Column Of A Table 4111** 4112** ^This routine returns metadata about a specific column of a specific 4113** database table accessible using the [database connection] handle 4114** passed as the first function argument. 4115** 4116** ^The column is identified by the second, third and fourth parameters to 4117** this function. ^The second parameter is either the name of the database 4118** (i.e. "main", "temp", or an attached database) containing the specified 4119** table or NULL. ^If it is NULL, then all attached databases are searched 4120** for the table using the same algorithm used by the database engine to 4121** resolve unqualified table references. 4122** 4123** ^The third and fourth parameters to this function are the table and column 4124** name of the desired column, respectively. Neither of these parameters 4125** may be NULL. 4126** 4127** ^Metadata is returned by writing to the memory locations passed as the 5th 4128** and subsequent parameters to this function. ^Any of these arguments may be 4129** NULL, in which case the corresponding element of metadata is omitted. 4130** 4131** ^(<blockquote> 4132** <table border="1"> 4133** <tr><th> Parameter <th> Output<br>Type <th> Description 4134** 4135** <tr><td> 5th <td> const char* <td> Data type 4136** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4137** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4138** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4139** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4140** </table> 4141** </blockquote>)^ 4142** 4143** ^The memory pointed to by the character pointers returned for the 4144** declaration type and collation sequence is valid only until the next 4145** call to any SQLite API function. 4146** 4147** ^If the specified table is actually a view, an [error code] is returned. 4148** 4149** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4150** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4151** parameters are set for the explicitly declared column. ^(If there is no 4152** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4153** parameters are set as follows: 4154** 4155** <pre> 4156** data type: "INTEGER" 4157** collation sequence: "BINARY" 4158** not null: 0 4159** primary key: 1 4160** auto increment: 0 4161** </pre>)^ 4162** 4163** ^(This function may load one or more schemas from database files. If an 4164** error occurs during this process, or if the requested table or column 4165** cannot be found, an [error code] is returned and an error message left 4166** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4167** 4168** ^This API is only available if the library was compiled with the 4169** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4170*/ 4171int sqlite3_table_column_metadata( 4172 sqlite3 *db, /* Connection handle */ 4173 const char *zDbName, /* Database name or NULL */ 4174 const char *zTableName, /* Table name */ 4175 const char *zColumnName, /* Column name */ 4176 char const **pzDataType, /* OUTPUT: Declared data type */ 4177 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4178 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4179 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4180 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4181); 4182 4183/* 4184** CAPI3REF: Load An Extension 4185** 4186** ^This interface loads an SQLite extension library from the named file. 4187** 4188** ^The sqlite3_load_extension() interface attempts to load an 4189** SQLite extension library contained in the file zFile. 4190** 4191** ^The entry point is zProc. 4192** ^zProc may be 0, in which case the name of the entry point 4193** defaults to "sqlite3_extension_init". 4194** ^The sqlite3_load_extension() interface returns 4195** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4196** ^If an error occurs and pzErrMsg is not 0, then the 4197** [sqlite3_load_extension()] interface shall attempt to 4198** fill *pzErrMsg with error message text stored in memory 4199** obtained from [sqlite3_malloc()]. The calling function 4200** should free this memory by calling [sqlite3_free()]. 4201** 4202** ^Extension loading must be enabled using 4203** [sqlite3_enable_load_extension()] prior to calling this API, 4204** otherwise an error will be returned. 4205** 4206** See also the [load_extension() SQL function]. 4207*/ 4208int sqlite3_load_extension( 4209 sqlite3 *db, /* Load the extension into this database connection */ 4210 const char *zFile, /* Name of the shared library containing extension */ 4211 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4212 char **pzErrMsg /* Put error message here if not 0 */ 4213); 4214 4215/* 4216** CAPI3REF: Enable Or Disable Extension Loading 4217** 4218** ^So as not to open security holes in older applications that are 4219** unprepared to deal with extension loading, and as a means of disabling 4220** extension loading while evaluating user-entered SQL, the following API 4221** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4222** 4223** ^Extension loading is off by default. See ticket #1863. 4224** ^Call the sqlite3_enable_load_extension() routine with onoff==1 4225** to turn extension loading on and call it with onoff==0 to turn 4226** it back off again. 4227*/ 4228int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4229 4230/* 4231** CAPI3REF: Automatically Load An Extensions 4232** 4233** ^This API can be invoked at program startup in order to register 4234** one or more statically linked extensions that will be available 4235** to all new [database connections]. 4236** 4237** ^(This routine stores a pointer to the extension entry point 4238** in an array that is obtained from [sqlite3_malloc()]. That memory 4239** is deallocated by [sqlite3_reset_auto_extension()].)^ 4240** 4241** ^This function registers an extension entry point that is 4242** automatically invoked whenever a new [database connection] 4243** is opened using [sqlite3_open()], [sqlite3_open16()], 4244** or [sqlite3_open_v2()]. 4245** ^Duplicate extensions are detected so calling this routine 4246** multiple times with the same extension is harmless. 4247** ^Automatic extensions apply across all threads. 4248*/ 4249int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4250 4251/* 4252** CAPI3REF: Reset Automatic Extension Loading 4253** 4254** ^(This function disables all previously registered automatic 4255** extensions. It undoes the effect of all prior 4256** [sqlite3_auto_extension()] calls.)^ 4257** 4258** ^This function disables automatic extensions in all threads. 4259*/ 4260void sqlite3_reset_auto_extension(void); 4261 4262/* 4263** The interface to the virtual-table mechanism is currently considered 4264** to be experimental. The interface might change in incompatible ways. 4265** If this is a problem for you, do not use the interface at this time. 4266** 4267** When the virtual-table mechanism stabilizes, we will declare the 4268** interface fixed, support it indefinitely, and remove this comment. 4269*/ 4270 4271/* 4272** Structures used by the virtual table interface 4273*/ 4274typedef struct sqlite3_vtab sqlite3_vtab; 4275typedef struct sqlite3_index_info sqlite3_index_info; 4276typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4277typedef struct sqlite3_module sqlite3_module; 4278 4279/* 4280** CAPI3REF: Virtual Table Object 4281** KEYWORDS: sqlite3_module {virtual table module} 4282** 4283** This structure, sometimes called a a "virtual table module", 4284** defines the implementation of a [virtual tables]. 4285** This structure consists mostly of methods for the module. 4286** 4287** ^A virtual table module is created by filling in a persistent 4288** instance of this structure and passing a pointer to that instance 4289** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4290** ^The registration remains valid until it is replaced by a different 4291** module or until the [database connection] closes. The content 4292** of this structure must not change while it is registered with 4293** any database connection. 4294*/ 4295struct sqlite3_module { 4296 int iVersion; 4297 int (*xCreate)(sqlite3*, void *pAux, 4298 int argc, const char *const*argv, 4299 sqlite3_vtab **ppVTab, char**); 4300 int (*xConnect)(sqlite3*, void *pAux, 4301 int argc, const char *const*argv, 4302 sqlite3_vtab **ppVTab, char**); 4303 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4304 int (*xDisconnect)(sqlite3_vtab *pVTab); 4305 int (*xDestroy)(sqlite3_vtab *pVTab); 4306 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4307 int (*xClose)(sqlite3_vtab_cursor*); 4308 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4309 int argc, sqlite3_value **argv); 4310 int (*xNext)(sqlite3_vtab_cursor*); 4311 int (*xEof)(sqlite3_vtab_cursor*); 4312 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4313 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4314 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4315 int (*xBegin)(sqlite3_vtab *pVTab); 4316 int (*xSync)(sqlite3_vtab *pVTab); 4317 int (*xCommit)(sqlite3_vtab *pVTab); 4318 int (*xRollback)(sqlite3_vtab *pVTab); 4319 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4320 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4321 void **ppArg); 4322 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4323}; 4324 4325/* 4326** CAPI3REF: Virtual Table Indexing Information 4327** KEYWORDS: sqlite3_index_info 4328** 4329** The sqlite3_index_info structure and its substructures is used as part 4330** of the [virtual table] interface to 4331** pass information into and receive the reply from the [xBestIndex] 4332** method of a [virtual table module]. The fields under **Inputs** are the 4333** inputs to xBestIndex and are read-only. xBestIndex inserts its 4334** results into the **Outputs** fields. 4335** 4336** ^(The aConstraint[] array records WHERE clause constraints of the form: 4337** 4338** <blockquote>column OP expr</blockquote> 4339** 4340** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 4341** stored in aConstraint[].op using one of the 4342** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 4343** ^(The index of the column is stored in 4344** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 4345** expr on the right-hand side can be evaluated (and thus the constraint 4346** is usable) and false if it cannot.)^ 4347** 4348** ^The optimizer automatically inverts terms of the form "expr OP column" 4349** and makes other simplifications to the WHERE clause in an attempt to 4350** get as many WHERE clause terms into the form shown above as possible. 4351** ^The aConstraint[] array only reports WHERE clause terms that are 4352** relevant to the particular virtual table being queried. 4353** 4354** ^Information about the ORDER BY clause is stored in aOrderBy[]. 4355** ^Each term of aOrderBy records a column of the ORDER BY clause. 4356** 4357** The [xBestIndex] method must fill aConstraintUsage[] with information 4358** about what parameters to pass to xFilter. ^If argvIndex>0 then 4359** the right-hand side of the corresponding aConstraint[] is evaluated 4360** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 4361** is true, then the constraint is assumed to be fully handled by the 4362** virtual table and is not checked again by SQLite.)^ 4363** 4364** ^The idxNum and idxPtr values are recorded and passed into the 4365** [xFilter] method. 4366** ^[sqlite3_free()] is used to free idxPtr if and only if 4367** needToFreeIdxPtr is true. 4368** 4369** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 4370** the correct order to satisfy the ORDER BY clause so that no separate 4371** sorting step is required. 4372** 4373** ^The estimatedCost value is an estimate of the cost of doing the 4374** particular lookup. A full scan of a table with N entries should have 4375** a cost of N. A binary search of a table of N entries should have a 4376** cost of approximately log(N). 4377*/ 4378struct sqlite3_index_info { 4379 /* Inputs */ 4380 int nConstraint; /* Number of entries in aConstraint */ 4381 struct sqlite3_index_constraint { 4382 int iColumn; /* Column on left-hand side of constraint */ 4383 unsigned char op; /* Constraint operator */ 4384 unsigned char usable; /* True if this constraint is usable */ 4385 int iTermOffset; /* Used internally - xBestIndex should ignore */ 4386 } *aConstraint; /* Table of WHERE clause constraints */ 4387 int nOrderBy; /* Number of terms in the ORDER BY clause */ 4388 struct sqlite3_index_orderby { 4389 int iColumn; /* Column number */ 4390 unsigned char desc; /* True for DESC. False for ASC. */ 4391 } *aOrderBy; /* The ORDER BY clause */ 4392 /* Outputs */ 4393 struct sqlite3_index_constraint_usage { 4394 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 4395 unsigned char omit; /* Do not code a test for this constraint */ 4396 } *aConstraintUsage; 4397 int idxNum; /* Number used to identify the index */ 4398 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 4399 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 4400 int orderByConsumed; /* True if output is already ordered */ 4401 double estimatedCost; /* Estimated cost of using this index */ 4402}; 4403 4404/* 4405** CAPI3REF: Virtual Table Constraint Operator Codes 4406** 4407** These macros defined the allowed values for the 4408** [sqlite3_index_info].aConstraint[].op field. Each value represents 4409** an operator that is part of a constraint term in the wHERE clause of 4410** a query that uses a [virtual table]. 4411*/ 4412#define SQLITE_INDEX_CONSTRAINT_EQ 2 4413#define SQLITE_INDEX_CONSTRAINT_GT 4 4414#define SQLITE_INDEX_CONSTRAINT_LE 8 4415#define SQLITE_INDEX_CONSTRAINT_LT 16 4416#define SQLITE_INDEX_CONSTRAINT_GE 32 4417#define SQLITE_INDEX_CONSTRAINT_MATCH 64 4418 4419/* 4420** CAPI3REF: Register A Virtual Table Implementation 4421** 4422** ^These routines are used to register a new [virtual table module] name. 4423** ^Module names must be registered before 4424** creating a new [virtual table] using the module and before using a 4425** preexisting [virtual table] for the module. 4426** 4427** ^The module name is registered on the [database connection] specified 4428** by the first parameter. ^The name of the module is given by the 4429** second parameter. ^The third parameter is a pointer to 4430** the implementation of the [virtual table module]. ^The fourth 4431** parameter is an arbitrary client data pointer that is passed through 4432** into the [xCreate] and [xConnect] methods of the virtual table module 4433** when a new virtual table is be being created or reinitialized. 4434** 4435** ^The sqlite3_create_module_v2() interface has a fifth parameter which 4436** is a pointer to a destructor for the pClientData. ^SQLite will 4437** invoke the destructor function (if it is not NULL) when SQLite 4438** no longer needs the pClientData pointer. ^The sqlite3_create_module() 4439** interface is equivalent to sqlite3_create_module_v2() with a NULL 4440** destructor. 4441*/ 4442int sqlite3_create_module( 4443 sqlite3 *db, /* SQLite connection to register module with */ 4444 const char *zName, /* Name of the module */ 4445 const sqlite3_module *p, /* Methods for the module */ 4446 void *pClientData /* Client data for xCreate/xConnect */ 4447); 4448int sqlite3_create_module_v2( 4449 sqlite3 *db, /* SQLite connection to register module with */ 4450 const char *zName, /* Name of the module */ 4451 const sqlite3_module *p, /* Methods for the module */ 4452 void *pClientData, /* Client data for xCreate/xConnect */ 4453 void(*xDestroy)(void*) /* Module destructor function */ 4454); 4455 4456/* 4457** CAPI3REF: Virtual Table Instance Object 4458** KEYWORDS: sqlite3_vtab 4459** 4460** Every [virtual table module] implementation uses a subclass 4461** of this object to describe a particular instance 4462** of the [virtual table]. Each subclass will 4463** be tailored to the specific needs of the module implementation. 4464** The purpose of this superclass is to define certain fields that are 4465** common to all module implementations. 4466** 4467** ^Virtual tables methods can set an error message by assigning a 4468** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 4469** take care that any prior string is freed by a call to [sqlite3_free()] 4470** prior to assigning a new string to zErrMsg. ^After the error message 4471** is delivered up to the client application, the string will be automatically 4472** freed by sqlite3_free() and the zErrMsg field will be zeroed. 4473*/ 4474struct sqlite3_vtab { 4475 const sqlite3_module *pModule; /* The module for this virtual table */ 4476 int nRef; /* NO LONGER USED */ 4477 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 4478 /* Virtual table implementations will typically add additional fields */ 4479}; 4480 4481/* 4482** CAPI3REF: Virtual Table Cursor Object 4483** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 4484** 4485** Every [virtual table module] implementation uses a subclass of the 4486** following structure to describe cursors that point into the 4487** [virtual table] and are used 4488** to loop through the virtual table. Cursors are created using the 4489** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 4490** by the [sqlite3_module.xClose | xClose] method. Cursors are used 4491** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 4492** of the module. Each module implementation will define 4493** the content of a cursor structure to suit its own needs. 4494** 4495** This superclass exists in order to define fields of the cursor that 4496** are common to all implementations. 4497*/ 4498struct sqlite3_vtab_cursor { 4499 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 4500 /* Virtual table implementations will typically add additional fields */ 4501}; 4502 4503/* 4504** CAPI3REF: Declare The Schema Of A Virtual Table 4505** 4506** ^The [xCreate] and [xConnect] methods of a 4507** [virtual table module] call this interface 4508** to declare the format (the names and datatypes of the columns) of 4509** the virtual tables they implement. 4510*/ 4511int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 4512 4513/* 4514** CAPI3REF: Overload A Function For A Virtual Table 4515** 4516** ^(Virtual tables can provide alternative implementations of functions 4517** using the [xFindFunction] method of the [virtual table module]. 4518** But global versions of those functions 4519** must exist in order to be overloaded.)^ 4520** 4521** ^(This API makes sure a global version of a function with a particular 4522** name and number of parameters exists. If no such function exists 4523** before this API is called, a new function is created.)^ ^The implementation 4524** of the new function always causes an exception to be thrown. So 4525** the new function is not good for anything by itself. Its only 4526** purpose is to be a placeholder function that can be overloaded 4527** by a [virtual table]. 4528*/ 4529int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 4530 4531/* 4532** The interface to the virtual-table mechanism defined above (back up 4533** to a comment remarkably similar to this one) is currently considered 4534** to be experimental. The interface might change in incompatible ways. 4535** If this is a problem for you, do not use the interface at this time. 4536** 4537** When the virtual-table mechanism stabilizes, we will declare the 4538** interface fixed, support it indefinitely, and remove this comment. 4539*/ 4540 4541/* 4542** CAPI3REF: A Handle To An Open BLOB 4543** KEYWORDS: {BLOB handle} {BLOB handles} 4544** 4545** An instance of this object represents an open BLOB on which 4546** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 4547** ^Objects of this type are created by [sqlite3_blob_open()] 4548** and destroyed by [sqlite3_blob_close()]. 4549** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 4550** can be used to read or write small subsections of the BLOB. 4551** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 4552*/ 4553typedef struct sqlite3_blob sqlite3_blob; 4554 4555/* 4556** CAPI3REF: Open A BLOB For Incremental I/O 4557** 4558** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 4559** in row iRow, column zColumn, table zTable in database zDb; 4560** in other words, the same BLOB that would be selected by: 4561** 4562** <pre> 4563** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 4564** </pre>)^ 4565** 4566** ^If the flags parameter is non-zero, then the BLOB is opened for read 4567** and write access. ^If it is zero, the BLOB is opened for read access. 4568** ^It is not possible to open a column that is part of an index or primary 4569** key for writing. ^If [foreign key constraints] are enabled, it is 4570** not possible to open a column that is part of a [child key] for writing. 4571** 4572** ^Note that the database name is not the filename that contains 4573** the database but rather the symbolic name of the database that 4574** appears after the AS keyword when the database is connected using [ATTACH]. 4575** ^For the main database file, the database name is "main". 4576** ^For TEMP tables, the database name is "temp". 4577** 4578** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 4579** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 4580** to be a null pointer.)^ 4581** ^This function sets the [database connection] error code and message 4582** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 4583** functions. ^Note that the *ppBlob variable is always initialized in a 4584** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 4585** regardless of the success or failure of this routine. 4586** 4587** ^(If the row that a BLOB handle points to is modified by an 4588** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 4589** then the BLOB handle is marked as "expired". 4590** This is true if any column of the row is changed, even a column 4591** other than the one the BLOB handle is open on.)^ 4592** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 4593** a expired BLOB handle fail with an return code of [SQLITE_ABORT]. 4594** ^(Changes written into a BLOB prior to the BLOB expiring are not 4595** rolled back by the expiration of the BLOB. Such changes will eventually 4596** commit if the transaction continues to completion.)^ 4597** 4598** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 4599** the opened blob. ^The size of a blob may not be changed by this 4600** interface. Use the [UPDATE] SQL command to change the size of a 4601** blob. 4602** 4603** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 4604** and the built-in [zeroblob] SQL function can be used, if desired, 4605** to create an empty, zero-filled blob in which to read or write using 4606** this interface. 4607** 4608** To avoid a resource leak, every open [BLOB handle] should eventually 4609** be released by a call to [sqlite3_blob_close()]. 4610*/ 4611int sqlite3_blob_open( 4612 sqlite3*, 4613 const char *zDb, 4614 const char *zTable, 4615 const char *zColumn, 4616 sqlite3_int64 iRow, 4617 int flags, 4618 sqlite3_blob **ppBlob 4619); 4620 4621/* 4622** CAPI3REF: Close A BLOB Handle 4623** 4624** ^Closes an open [BLOB handle]. 4625** 4626** ^Closing a BLOB shall cause the current transaction to commit 4627** if there are no other BLOBs, no pending prepared statements, and the 4628** database connection is in [autocommit mode]. 4629** ^If any writes were made to the BLOB, they might be held in cache 4630** until the close operation if they will fit. 4631** 4632** ^(Closing the BLOB often forces the changes 4633** out to disk and so if any I/O errors occur, they will likely occur 4634** at the time when the BLOB is closed. Any errors that occur during 4635** closing are reported as a non-zero return value.)^ 4636** 4637** ^(The BLOB is closed unconditionally. Even if this routine returns 4638** an error code, the BLOB is still closed.)^ 4639** 4640** ^Calling this routine with a null pointer (such as would be returned 4641** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 4642*/ 4643int sqlite3_blob_close(sqlite3_blob *); 4644 4645/* 4646** CAPI3REF: Return The Size Of An Open BLOB 4647** 4648** ^Returns the size in bytes of the BLOB accessible via the 4649** successfully opened [BLOB handle] in its only argument. ^The 4650** incremental blob I/O routines can only read or overwriting existing 4651** blob content; they cannot change the size of a blob. 4652** 4653** This routine only works on a [BLOB handle] which has been created 4654** by a prior successful call to [sqlite3_blob_open()] and which has not 4655** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4656** to this routine results in undefined and probably undesirable behavior. 4657*/ 4658int sqlite3_blob_bytes(sqlite3_blob *); 4659 4660/* 4661** CAPI3REF: Read Data From A BLOB Incrementally 4662** 4663** ^(This function is used to read data from an open [BLOB handle] into a 4664** caller-supplied buffer. N bytes of data are copied into buffer Z 4665** from the open BLOB, starting at offset iOffset.)^ 4666** 4667** ^If offset iOffset is less than N bytes from the end of the BLOB, 4668** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 4669** less than zero, [SQLITE_ERROR] is returned and no data is read. 4670** ^The size of the blob (and hence the maximum value of N+iOffset) 4671** can be determined using the [sqlite3_blob_bytes()] interface. 4672** 4673** ^An attempt to read from an expired [BLOB handle] fails with an 4674** error code of [SQLITE_ABORT]. 4675** 4676** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 4677** Otherwise, an [error code] or an [extended error code] is returned.)^ 4678** 4679** This routine only works on a [BLOB handle] which has been created 4680** by a prior successful call to [sqlite3_blob_open()] and which has not 4681** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4682** to this routine results in undefined and probably undesirable behavior. 4683** 4684** See also: [sqlite3_blob_write()]. 4685*/ 4686int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 4687 4688/* 4689** CAPI3REF: Write Data Into A BLOB Incrementally 4690** 4691** ^This function is used to write data into an open [BLOB handle] from a 4692** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 4693** into the open BLOB, starting at offset iOffset. 4694** 4695** ^If the [BLOB handle] passed as the first argument was not opened for 4696** writing (the flags parameter to [sqlite3_blob_open()] was zero), 4697** this function returns [SQLITE_READONLY]. 4698** 4699** ^This function may only modify the contents of the BLOB; it is 4700** not possible to increase the size of a BLOB using this API. 4701** ^If offset iOffset is less than N bytes from the end of the BLOB, 4702** [SQLITE_ERROR] is returned and no data is written. ^If N is 4703** less than zero [SQLITE_ERROR] is returned and no data is written. 4704** The size of the BLOB (and hence the maximum value of N+iOffset) 4705** can be determined using the [sqlite3_blob_bytes()] interface. 4706** 4707** ^An attempt to write to an expired [BLOB handle] fails with an 4708** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 4709** before the [BLOB handle] expired are not rolled back by the 4710** expiration of the handle, though of course those changes might 4711** have been overwritten by the statement that expired the BLOB handle 4712** or by other independent statements. 4713** 4714** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 4715** Otherwise, an [error code] or an [extended error code] is returned.)^ 4716** 4717** This routine only works on a [BLOB handle] which has been created 4718** by a prior successful call to [sqlite3_blob_open()] and which has not 4719** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4720** to this routine results in undefined and probably undesirable behavior. 4721** 4722** See also: [sqlite3_blob_read()]. 4723*/ 4724int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 4725 4726/* 4727** CAPI3REF: Virtual File System Objects 4728** 4729** A virtual filesystem (VFS) is an [sqlite3_vfs] object 4730** that SQLite uses to interact 4731** with the underlying operating system. Most SQLite builds come with a 4732** single default VFS that is appropriate for the host computer. 4733** New VFSes can be registered and existing VFSes can be unregistered. 4734** The following interfaces are provided. 4735** 4736** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 4737** ^Names are case sensitive. 4738** ^Names are zero-terminated UTF-8 strings. 4739** ^If there is no match, a NULL pointer is returned. 4740** ^If zVfsName is NULL then the default VFS is returned. 4741** 4742** ^New VFSes are registered with sqlite3_vfs_register(). 4743** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 4744** ^The same VFS can be registered multiple times without injury. 4745** ^To make an existing VFS into the default VFS, register it again 4746** with the makeDflt flag set. If two different VFSes with the 4747** same name are registered, the behavior is undefined. If a 4748** VFS is registered with a name that is NULL or an empty string, 4749** then the behavior is undefined. 4750** 4751** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 4752** ^(If the default VFS is unregistered, another VFS is chosen as 4753** the default. The choice for the new VFS is arbitrary.)^ 4754*/ 4755sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 4756int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 4757int sqlite3_vfs_unregister(sqlite3_vfs*); 4758 4759/* 4760** CAPI3REF: Mutexes 4761** 4762** The SQLite core uses these routines for thread 4763** synchronization. Though they are intended for internal 4764** use by SQLite, code that links against SQLite is 4765** permitted to use any of these routines. 4766** 4767** The SQLite source code contains multiple implementations 4768** of these mutex routines. An appropriate implementation 4769** is selected automatically at compile-time. ^(The following 4770** implementations are available in the SQLite core: 4771** 4772** <ul> 4773** <li> SQLITE_MUTEX_OS2 4774** <li> SQLITE_MUTEX_PTHREAD 4775** <li> SQLITE_MUTEX_W32 4776** <li> SQLITE_MUTEX_NOOP 4777** </ul>)^ 4778** 4779** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 4780** that does no real locking and is appropriate for use in 4781** a single-threaded application. ^The SQLITE_MUTEX_OS2, 4782** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations 4783** are appropriate for use on OS/2, Unix, and Windows. 4784** 4785** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 4786** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 4787** implementation is included with the library. In this case the 4788** application must supply a custom mutex implementation using the 4789** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 4790** before calling sqlite3_initialize() or any other public sqlite3_ 4791** function that calls sqlite3_initialize().)^ 4792** 4793** ^The sqlite3_mutex_alloc() routine allocates a new 4794** mutex and returns a pointer to it. ^If it returns NULL 4795** that means that a mutex could not be allocated. ^SQLite 4796** will unwind its stack and return an error. ^(The argument 4797** to sqlite3_mutex_alloc() is one of these integer constants: 4798** 4799** <ul> 4800** <li> SQLITE_MUTEX_FAST 4801** <li> SQLITE_MUTEX_RECURSIVE 4802** <li> SQLITE_MUTEX_STATIC_MASTER 4803** <li> SQLITE_MUTEX_STATIC_MEM 4804** <li> SQLITE_MUTEX_STATIC_MEM2 4805** <li> SQLITE_MUTEX_STATIC_PRNG 4806** <li> SQLITE_MUTEX_STATIC_LRU 4807** <li> SQLITE_MUTEX_STATIC_LRU2 4808** </ul>)^ 4809** 4810** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 4811** cause sqlite3_mutex_alloc() to create 4812** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 4813** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 4814** The mutex implementation does not need to make a distinction 4815** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 4816** not want to. ^SQLite will only request a recursive mutex in 4817** cases where it really needs one. ^If a faster non-recursive mutex 4818** implementation is available on the host platform, the mutex subsystem 4819** might return such a mutex in response to SQLITE_MUTEX_FAST. 4820** 4821** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 4822** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 4823** a pointer to a static preexisting mutex. ^Six static mutexes are 4824** used by the current version of SQLite. Future versions of SQLite 4825** may add additional static mutexes. Static mutexes are for internal 4826** use by SQLite only. Applications that use SQLite mutexes should 4827** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 4828** SQLITE_MUTEX_RECURSIVE. 4829** 4830** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 4831** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 4832** returns a different mutex on every call. ^But for the static 4833** mutex types, the same mutex is returned on every call that has 4834** the same type number. 4835** 4836** ^The sqlite3_mutex_free() routine deallocates a previously 4837** allocated dynamic mutex. ^SQLite is careful to deallocate every 4838** dynamic mutex that it allocates. The dynamic mutexes must not be in 4839** use when they are deallocated. Attempting to deallocate a static 4840** mutex results in undefined behavior. ^SQLite never deallocates 4841** a static mutex. 4842** 4843** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 4844** to enter a mutex. ^If another thread is already within the mutex, 4845** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 4846** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 4847** upon successful entry. ^(Mutexes created using 4848** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 4849** In such cases the, 4850** mutex must be exited an equal number of times before another thread 4851** can enter.)^ ^(If the same thread tries to enter any other 4852** kind of mutex more than once, the behavior is undefined. 4853** SQLite will never exhibit 4854** such behavior in its own use of mutexes.)^ 4855** 4856** ^(Some systems (for example, Windows 95) do not support the operation 4857** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 4858** will always return SQLITE_BUSY. The SQLite core only ever uses 4859** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 4860** 4861** ^The sqlite3_mutex_leave() routine exits a mutex that was 4862** previously entered by the same thread. ^(The behavior 4863** is undefined if the mutex is not currently entered by the 4864** calling thread or is not currently allocated. SQLite will 4865** never do either.)^ 4866** 4867** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 4868** sqlite3_mutex_leave() is a NULL pointer, then all three routines 4869** behave as no-ops. 4870** 4871** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 4872*/ 4873sqlite3_mutex *sqlite3_mutex_alloc(int); 4874void sqlite3_mutex_free(sqlite3_mutex*); 4875void sqlite3_mutex_enter(sqlite3_mutex*); 4876int sqlite3_mutex_try(sqlite3_mutex*); 4877void sqlite3_mutex_leave(sqlite3_mutex*); 4878 4879/* 4880** CAPI3REF: Mutex Methods Object 4881** 4882** An instance of this structure defines the low-level routines 4883** used to allocate and use mutexes. 4884** 4885** Usually, the default mutex implementations provided by SQLite are 4886** sufficient, however the user has the option of substituting a custom 4887** implementation for specialized deployments or systems for which SQLite 4888** does not provide a suitable implementation. In this case, the user 4889** creates and populates an instance of this structure to pass 4890** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 4891** Additionally, an instance of this structure can be used as an 4892** output variable when querying the system for the current mutex 4893** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 4894** 4895** ^The xMutexInit method defined by this structure is invoked as 4896** part of system initialization by the sqlite3_initialize() function. 4897** ^The xMutexInit routine is calle by SQLite exactly once for each 4898** effective call to [sqlite3_initialize()]. 4899** 4900** ^The xMutexEnd method defined by this structure is invoked as 4901** part of system shutdown by the sqlite3_shutdown() function. The 4902** implementation of this method is expected to release all outstanding 4903** resources obtained by the mutex methods implementation, especially 4904** those obtained by the xMutexInit method. ^The xMutexEnd() 4905** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 4906** 4907** ^(The remaining seven methods defined by this structure (xMutexAlloc, 4908** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 4909** xMutexNotheld) implement the following interfaces (respectively): 4910** 4911** <ul> 4912** <li> [sqlite3_mutex_alloc()] </li> 4913** <li> [sqlite3_mutex_free()] </li> 4914** <li> [sqlite3_mutex_enter()] </li> 4915** <li> [sqlite3_mutex_try()] </li> 4916** <li> [sqlite3_mutex_leave()] </li> 4917** <li> [sqlite3_mutex_held()] </li> 4918** <li> [sqlite3_mutex_notheld()] </li> 4919** </ul>)^ 4920** 4921** The only difference is that the public sqlite3_XXX functions enumerated 4922** above silently ignore any invocations that pass a NULL pointer instead 4923** of a valid mutex handle. The implementations of the methods defined 4924** by this structure are not required to handle this case, the results 4925** of passing a NULL pointer instead of a valid mutex handle are undefined 4926** (i.e. it is acceptable to provide an implementation that segfaults if 4927** it is passed a NULL pointer). 4928** 4929** The xMutexInit() method must be threadsafe. ^It must be harmless to 4930** invoke xMutexInit() mutiple times within the same process and without 4931** intervening calls to xMutexEnd(). Second and subsequent calls to 4932** xMutexInit() must be no-ops. 4933** 4934** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 4935** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 4936** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 4937** memory allocation for a fast or recursive mutex. 4938** 4939** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 4940** called, but only if the prior call to xMutexInit returned SQLITE_OK. 4941** If xMutexInit fails in any way, it is expected to clean up after itself 4942** prior to returning. 4943*/ 4944typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 4945struct sqlite3_mutex_methods { 4946 int (*xMutexInit)(void); 4947 int (*xMutexEnd)(void); 4948 sqlite3_mutex *(*xMutexAlloc)(int); 4949 void (*xMutexFree)(sqlite3_mutex *); 4950 void (*xMutexEnter)(sqlite3_mutex *); 4951 int (*xMutexTry)(sqlite3_mutex *); 4952 void (*xMutexLeave)(sqlite3_mutex *); 4953 int (*xMutexHeld)(sqlite3_mutex *); 4954 int (*xMutexNotheld)(sqlite3_mutex *); 4955}; 4956 4957/* 4958** CAPI3REF: Mutex Verification Routines 4959** 4960** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 4961** are intended for use inside assert() statements. ^The SQLite core 4962** never uses these routines except inside an assert() and applications 4963** are advised to follow the lead of the core. ^The SQLite core only 4964** provides implementations for these routines when it is compiled 4965** with the SQLITE_DEBUG flag. ^External mutex implementations 4966** are only required to provide these routines if SQLITE_DEBUG is 4967** defined and if NDEBUG is not defined. 4968** 4969** ^These routines should return true if the mutex in their argument 4970** is held or not held, respectively, by the calling thread. 4971** 4972** ^The implementation is not required to provided versions of these 4973** routines that actually work. If the implementation does not provide working 4974** versions of these routines, it should at least provide stubs that always 4975** return true so that one does not get spurious assertion failures. 4976** 4977** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 4978** the routine should return 1. This seems counter-intuitive since 4979** clearly the mutex cannot be held if it does not exist. But the 4980** the reason the mutex does not exist is because the build is not 4981** using mutexes. And we do not want the assert() containing the 4982** call to sqlite3_mutex_held() to fail, so a non-zero return is 4983** the appropriate thing to do. ^The sqlite3_mutex_notheld() 4984** interface should also return 1 when given a NULL pointer. 4985*/ 4986#ifndef NDEBUG 4987int sqlite3_mutex_held(sqlite3_mutex*); 4988int sqlite3_mutex_notheld(sqlite3_mutex*); 4989#endif 4990 4991/* 4992** CAPI3REF: Mutex Types 4993** 4994** The [sqlite3_mutex_alloc()] interface takes a single argument 4995** which is one of these integer constants. 4996** 4997** The set of static mutexes may change from one SQLite release to the 4998** next. Applications that override the built-in mutex logic must be 4999** prepared to accommodate additional static mutexes. 5000*/ 5001#define SQLITE_MUTEX_FAST 0 5002#define SQLITE_MUTEX_RECURSIVE 1 5003#define SQLITE_MUTEX_STATIC_MASTER 2 5004#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 5005#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 5006#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 5007#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 5008#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 5009#define SQLITE_MUTEX_STATIC_LRU2 7 /* lru page list */ 5010 5011/* 5012** CAPI3REF: Retrieve the mutex for a database connection 5013** 5014** ^This interface returns a pointer the [sqlite3_mutex] object that 5015** serializes access to the [database connection] given in the argument 5016** when the [threading mode] is Serialized. 5017** ^If the [threading mode] is Single-thread or Multi-thread then this 5018** routine returns a NULL pointer. 5019*/ 5020sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 5021 5022/* 5023** CAPI3REF: Low-Level Control Of Database Files 5024** 5025** ^The [sqlite3_file_control()] interface makes a direct call to the 5026** xFileControl method for the [sqlite3_io_methods] object associated 5027** with a particular database identified by the second argument. ^The 5028** name of the database "main" for the main database or "temp" for the 5029** TEMP database, or the name that appears after the AS keyword for 5030** databases that are added using the [ATTACH] SQL command. 5031** ^A NULL pointer can be used in place of "main" to refer to the 5032** main database file. 5033** ^The third and fourth parameters to this routine 5034** are passed directly through to the second and third parameters of 5035** the xFileControl method. ^The return value of the xFileControl 5036** method becomes the return value of this routine. 5037** 5038** ^If the second parameter (zDbName) does not match the name of any 5039** open database file, then SQLITE_ERROR is returned. ^This error 5040** code is not remembered and will not be recalled by [sqlite3_errcode()] 5041** or [sqlite3_errmsg()]. The underlying xFileControl method might 5042** also return SQLITE_ERROR. There is no way to distinguish between 5043** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5044** xFileControl method. 5045** 5046** See also: [SQLITE_FCNTL_LOCKSTATE] 5047*/ 5048int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5049 5050/* 5051** CAPI3REF: Testing Interface 5052** 5053** ^The sqlite3_test_control() interface is used to read out internal 5054** state of SQLite and to inject faults into SQLite for testing 5055** purposes. ^The first parameter is an operation code that determines 5056** the number, meaning, and operation of all subsequent parameters. 5057** 5058** This interface is not for use by applications. It exists solely 5059** for verifying the correct operation of the SQLite library. Depending 5060** on how the SQLite library is compiled, this interface might not exist. 5061** 5062** The details of the operation codes, their meanings, the parameters 5063** they take, and what they do are all subject to change without notice. 5064** Unlike most of the SQLite API, this function is not guaranteed to 5065** operate consistently from one release to the next. 5066*/ 5067int sqlite3_test_control(int op, ...); 5068 5069/* 5070** CAPI3REF: Testing Interface Operation Codes 5071** 5072** These constants are the valid operation code parameters used 5073** as the first argument to [sqlite3_test_control()]. 5074** 5075** These parameters and their meanings are subject to change 5076** without notice. These values are for testing purposes only. 5077** Applications should not use any of these parameters or the 5078** [sqlite3_test_control()] interface. 5079*/ 5080#define SQLITE_TESTCTRL_FIRST 5 5081#define SQLITE_TESTCTRL_PRNG_SAVE 5 5082#define SQLITE_TESTCTRL_PRNG_RESTORE 6 5083#define SQLITE_TESTCTRL_PRNG_RESET 7 5084#define SQLITE_TESTCTRL_BITVEC_TEST 8 5085#define SQLITE_TESTCTRL_FAULT_INSTALL 9 5086#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5087#define SQLITE_TESTCTRL_PENDING_BYTE 11 5088#define SQLITE_TESTCTRL_ASSERT 12 5089#define SQLITE_TESTCTRL_ALWAYS 13 5090#define SQLITE_TESTCTRL_RESERVE 14 5091#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 5092#define SQLITE_TESTCTRL_ISKEYWORD 16 5093#define SQLITE_TESTCTRL_PGHDRSZ 17 5094#define SQLITE_TESTCTRL_LAST 17 5095 5096/* 5097** CAPI3REF: SQLite Runtime Status 5098** 5099** ^This interface is used to retrieve runtime status information 5100** about the preformance of SQLite, and optionally to reset various 5101** highwater marks. ^The first argument is an integer code for 5102** the specific parameter to measure. ^(Recognized integer codes 5103** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].)^ 5104** ^The current value of the parameter is returned into *pCurrent. 5105** ^The highest recorded value is returned in *pHighwater. ^If the 5106** resetFlag is true, then the highest record value is reset after 5107** *pHighwater is written. ^(Some parameters do not record the highest 5108** value. For those parameters 5109** nothing is written into *pHighwater and the resetFlag is ignored.)^ 5110** ^(Other parameters record only the highwater mark and not the current 5111** value. For these latter parameters nothing is written into *pCurrent.)^ 5112** 5113** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 5114** non-zero [error code] on failure. 5115** 5116** This routine is threadsafe but is not atomic. This routine can be 5117** called while other threads are running the same or different SQLite 5118** interfaces. However the values returned in *pCurrent and 5119** *pHighwater reflect the status of SQLite at different points in time 5120** and it is possible that another thread might change the parameter 5121** in between the times when *pCurrent and *pHighwater are written. 5122** 5123** See also: [sqlite3_db_status()] 5124*/ 5125int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 5126 5127 5128/* 5129** CAPI3REF: Status Parameters 5130** 5131** These integer constants designate various run-time status parameters 5132** that can be returned by [sqlite3_status()]. 5133** 5134** <dl> 5135** ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 5136** <dd>This parameter is the current amount of memory checked out 5137** using [sqlite3_malloc()], either directly or indirectly. The 5138** figure includes calls made to [sqlite3_malloc()] by the application 5139** and internal memory usage by the SQLite library. Scratch memory 5140** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 5141** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 5142** this parameter. The amount returned is the sum of the allocation 5143** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 5144** 5145** ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 5146** <dd>This parameter records the largest memory allocation request 5147** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 5148** internal equivalents). Only the value returned in the 5149** *pHighwater parameter to [sqlite3_status()] is of interest. 5150** The value written into the *pCurrent parameter is undefined.</dd>)^ 5151** 5152** ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 5153** <dd>This parameter records the number of separate memory allocations.</dd>)^ 5154** 5155** ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 5156** <dd>This parameter returns the number of pages used out of the 5157** [pagecache memory allocator] that was configured using 5158** [SQLITE_CONFIG_PAGECACHE]. The 5159** value returned is in pages, not in bytes.</dd>)^ 5160** 5161** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5162** <dd>This parameter returns the number of bytes of page cache 5163** allocation which could not be statisfied by the [SQLITE_CONFIG_PAGECACHE] 5164** buffer and where forced to overflow to [sqlite3_malloc()]. The 5165** returned value includes allocations that overflowed because they 5166** where too large (they were larger than the "sz" parameter to 5167** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 5168** no space was left in the page cache.</dd>)^ 5169** 5170** ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 5171** <dd>This parameter records the largest memory allocation request 5172** handed to [pagecache memory allocator]. Only the value returned in the 5173** *pHighwater parameter to [sqlite3_status()] is of interest. 5174** The value written into the *pCurrent parameter is undefined.</dd>)^ 5175** 5176** ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 5177** <dd>This parameter returns the number of allocations used out of the 5178** [scratch memory allocator] configured using 5179** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5180** in bytes. Since a single thread may only have one scratch allocation 5181** outstanding at time, this parameter also reports the number of threads 5182** using scratch memory at the same time.</dd>)^ 5183** 5184** ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5185** <dd>This parameter returns the number of bytes of scratch memory 5186** allocation which could not be statisfied by the [SQLITE_CONFIG_SCRATCH] 5187** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5188** returned include overflows because the requested allocation was too 5189** larger (that is, because the requested allocation was larger than the 5190** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5191** slots were available. 5192** </dd>)^ 5193** 5194** ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5195** <dd>This parameter records the largest memory allocation request 5196** handed to [scratch memory allocator]. Only the value returned in the 5197** *pHighwater parameter to [sqlite3_status()] is of interest. 5198** The value written into the *pCurrent parameter is undefined.</dd>)^ 5199** 5200** ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 5201** <dd>This parameter records the deepest parser stack. It is only 5202** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 5203** </dl> 5204** 5205** New status parameters may be added from time to time. 5206*/ 5207#define SQLITE_STATUS_MEMORY_USED 0 5208#define SQLITE_STATUS_PAGECACHE_USED 1 5209#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5210#define SQLITE_STATUS_SCRATCH_USED 3 5211#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5212#define SQLITE_STATUS_MALLOC_SIZE 5 5213#define SQLITE_STATUS_PARSER_STACK 6 5214#define SQLITE_STATUS_PAGECACHE_SIZE 7 5215#define SQLITE_STATUS_SCRATCH_SIZE 8 5216#define SQLITE_STATUS_MALLOC_COUNT 9 5217 5218/* 5219** CAPI3REF: Database Connection Status 5220** 5221** ^This interface is used to retrieve runtime status information 5222** about a single [database connection]. ^The first argument is the 5223** database connection object to be interrogated. ^The second argument 5224** is an integer constant, taken from the set of 5225** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros, that 5226** determiness the parameter to interrogate. The set of 5227** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros is likely 5228** to grow in future releases of SQLite. 5229** 5230** ^The current value of the requested parameter is written into *pCur 5231** and the highest instantaneous value is written into *pHiwtr. ^If 5232** the resetFlg is true, then the highest instantaneous value is 5233** reset back down to the current value. 5234** 5235** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5236*/ 5237int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5238 5239/* 5240** CAPI3REF: Status Parameters for database connections 5241** 5242** These constants are the available integer "verbs" that can be passed as 5243** the second argument to the [sqlite3_db_status()] interface. 5244** 5245** New verbs may be added in future releases of SQLite. Existing verbs 5246** might be discontinued. Applications should check the return code from 5247** [sqlite3_db_status()] to make sure that the call worked. 5248** The [sqlite3_db_status()] interface will return a non-zero error code 5249** if a discontinued or unsupported verb is invoked. 5250** 5251** <dl> 5252** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5253** <dd>This parameter returns the number of lookaside memory slots currently 5254** checked out.</dd>)^ 5255** 5256** ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 5257** <dd>This parameter returns the approximate number of of bytes of heap 5258** memory used by all pager caches associated with the database connection.)^ 5259** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 5260** 5261** ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 5262** <dd>This parameter returns the approximate number of of bytes of heap 5263** memory used to store the schema for all databases associated 5264** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 5265** ^The full amount of memory used by the schemas is reported, even if the 5266** schema memory is shared with other database connections due to 5267** [shared cache mode] being enabled. 5268** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 5269** 5270** ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 5271** <dd>This parameter returns the approximate number of of bytes of heap 5272** and lookaside memory used by all prepared statements associated with 5273** the database connection.)^ 5274** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 5275** </dd> 5276** </dl> 5277*/ 5278#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 5279#define SQLITE_DBSTATUS_CACHE_USED 1 5280#define SQLITE_DBSTATUS_SCHEMA_USED 2 5281#define SQLITE_DBSTATUS_STMT_USED 3 5282#define SQLITE_DBSTATUS_MAX 3 /* Largest defined DBSTATUS */ 5283 5284 5285/* 5286** CAPI3REF: Prepared Statement Status 5287** 5288** ^(Each prepared statement maintains various 5289** [SQLITE_STMTSTATUS_SORT | counters] that measure the number 5290** of times it has performed specific operations.)^ These counters can 5291** be used to monitor the performance characteristics of the prepared 5292** statements. For example, if the number of table steps greatly exceeds 5293** the number of table searches or result rows, that would tend to indicate 5294** that the prepared statement is using a full table scan rather than 5295** an index. 5296** 5297** ^(This interface is used to retrieve and reset counter values from 5298** a [prepared statement]. The first argument is the prepared statement 5299** object to be interrogated. The second argument 5300** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter] 5301** to be interrogated.)^ 5302** ^The current value of the requested counter is returned. 5303** ^If the resetFlg is true, then the counter is reset to zero after this 5304** interface call returns. 5305** 5306** See also: [sqlite3_status()] and [sqlite3_db_status()]. 5307*/ 5308int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 5309 5310/* 5311** CAPI3REF: Status Parameters for prepared statements 5312** 5313** These preprocessor macros define integer codes that name counter 5314** values associated with the [sqlite3_stmt_status()] interface. 5315** The meanings of the various counters are as follows: 5316** 5317** <dl> 5318** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 5319** <dd>^This is the number of times that SQLite has stepped forward in 5320** a table as part of a full table scan. Large numbers for this counter 5321** may indicate opportunities for performance improvement through 5322** careful use of indices.</dd> 5323** 5324** <dt>SQLITE_STMTSTATUS_SORT</dt> 5325** <dd>^This is the number of sort operations that have occurred. 5326** A non-zero value in this counter may indicate an opportunity to 5327** improvement performance through careful use of indices.</dd> 5328** 5329** <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 5330** <dd>^This is the number of rows inserted into transient indices that 5331** were created automatically in order to help joins run faster. 5332** A non-zero value in this counter may indicate an opportunity to 5333** improvement performance by adding permanent indices that do not 5334** need to be reinitialized each time the statement is run.</dd> 5335** 5336** </dl> 5337*/ 5338#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 5339#define SQLITE_STMTSTATUS_SORT 2 5340#define SQLITE_STMTSTATUS_AUTOINDEX 3 5341 5342/* 5343** CAPI3REF: Custom Page Cache Object 5344** 5345** The sqlite3_pcache type is opaque. It is implemented by 5346** the pluggable module. The SQLite core has no knowledge of 5347** its size or internal structure and never deals with the 5348** sqlite3_pcache object except by holding and passing pointers 5349** to the object. 5350** 5351** See [sqlite3_pcache_methods] for additional information. 5352*/ 5353typedef struct sqlite3_pcache sqlite3_pcache; 5354 5355/* 5356** CAPI3REF: Application Defined Page Cache. 5357** KEYWORDS: {page cache} 5358** 5359** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can 5360** register an alternative page cache implementation by passing in an 5361** instance of the sqlite3_pcache_methods structure.)^ The majority of the 5362** heap memory used by SQLite is used by the page cache to cache data read 5363** from, or ready to be written to, the database file. By implementing a 5364** custom page cache using this API, an application can control more 5365** precisely the amount of memory consumed by SQLite, the way in which 5366** that memory is allocated and released, and the policies used to 5367** determine exactly which parts of a database file are cached and for 5368** how long. 5369** 5370** ^(The contents of the sqlite3_pcache_methods structure are copied to an 5371** internal buffer by SQLite within the call to [sqlite3_config]. Hence 5372** the application may discard the parameter after the call to 5373** [sqlite3_config()] returns.)^ 5374** 5375** ^The xInit() method is called once for each call to [sqlite3_initialize()] 5376** (usually only once during the lifetime of the process). ^(The xInit() 5377** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^ 5378** ^The xInit() method can set up up global structures and/or any mutexes 5379** required by the custom page cache implementation. 5380** 5381** ^The xShutdown() method is called from within [sqlite3_shutdown()], 5382** if the application invokes this API. It can be used to clean up 5383** any outstanding resources before process shutdown, if required. 5384** 5385** ^SQLite holds a [SQLITE_MUTEX_RECURSIVE] mutex when it invokes 5386** the xInit method, so the xInit method need not be threadsafe. ^The 5387** xShutdown method is only called from [sqlite3_shutdown()] so it does 5388** not need to be threadsafe either. All other methods must be threadsafe 5389** in multithreaded applications. 5390** 5391** ^SQLite will never invoke xInit() more than once without an intervening 5392** call to xShutdown(). 5393** 5394** ^The xCreate() method is used to construct a new cache instance. SQLite 5395** will typically create one cache instance for each open database file, 5396** though this is not guaranteed. ^The 5397** first parameter, szPage, is the size in bytes of the pages that must 5398** be allocated by the cache. ^szPage will not be a power of two. ^szPage 5399** will the page size of the database file that is to be cached plus an 5400** increment (here called "R") of about 100 or 200. ^SQLite will use the 5401** extra R bytes on each page to store metadata about the underlying 5402** database page on disk. The value of R depends 5403** on the SQLite version, the target platform, and how SQLite was compiled. 5404** ^R is constant for a particular build of SQLite. ^The second argument to 5405** xCreate(), bPurgeable, is true if the cache being created will 5406** be used to cache database pages of a file stored on disk, or 5407** false if it is used for an in-memory database. ^The cache implementation 5408** does not have to do anything special based with the value of bPurgeable; 5409** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 5410** never invoke xUnpin() except to deliberately delete a page. 5411** ^In other words, a cache created with bPurgeable set to false will 5412** never contain any unpinned pages. 5413** 5414** ^(The xCachesize() method may be called at any time by SQLite to set the 5415** suggested maximum cache-size (number of pages stored by) the cache 5416** instance passed as the first argument. This is the value configured using 5417** the SQLite "[PRAGMA cache_size]" command.)^ ^As with the bPurgeable 5418** parameter, the implementation is not required to do anything with this 5419** value; it is advisory only. 5420** 5421** ^The xPagecount() method should return the number of pages currently 5422** stored in the cache. 5423** 5424** ^The xFetch() method is used to fetch a page and return a pointer to it. 5425** ^A 'page', in this context, is a buffer of szPage bytes aligned at an 5426** 8-byte boundary. ^The page to be fetched is determined by the key. ^The 5427** mimimum key value is 1. After it has been retrieved using xFetch, the page 5428** is considered to be "pinned". 5429** 5430** ^If the requested page is already in the page cache, then the page cache 5431** implementation must return a pointer to the page buffer with its content 5432** intact. ^(If the requested page is not already in the cache, then the 5433** behavior of the cache implementation is determined by the value of the 5434** createFlag parameter passed to xFetch, according to the following table: 5435** 5436** <table border=1 width=85% align=center> 5437** <tr><th> createFlag <th> Behaviour when page is not already in cache 5438** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 5439** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 5440** Otherwise return NULL. 5441** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 5442** NULL if allocating a new page is effectively impossible. 5443** </table>)^ 5444** 5445** SQLite will normally invoke xFetch() with a createFlag of 0 or 1. If 5446** a call to xFetch() with createFlag==1 returns NULL, then SQLite will 5447** attempt to unpin one or more cache pages by spilling the content of 5448** pinned pages to disk and synching the operating system disk cache. After 5449** attempting to unpin pages, the xFetch() method will be invoked again with 5450** a createFlag of 2. 5451** 5452** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 5453** as its second argument. ^(If the third parameter, discard, is non-zero, 5454** then the page should be evicted from the cache. In this case SQLite 5455** assumes that the next time the page is retrieved from the cache using 5456** the xFetch() method, it will be zeroed.)^ ^If the discard parameter is 5457** zero, then the page is considered to be unpinned. ^The cache implementation 5458** may choose to evict unpinned pages at any time. 5459** 5460** ^(The cache is not required to perform any reference counting. A single 5461** call to xUnpin() unpins the page regardless of the number of prior calls 5462** to xFetch().)^ 5463** 5464** ^The xRekey() method is used to change the key value associated with the 5465** page passed as the second argument from oldKey to newKey. ^If the cache 5466** previously contains an entry associated with newKey, it should be 5467** discarded. ^Any prior cache entry associated with newKey is guaranteed not 5468** to be pinned. 5469** 5470** ^When SQLite calls the xTruncate() method, the cache must discard all 5471** existing cache entries with page numbers (keys) greater than or equal 5472** to the value of the iLimit parameter passed to xTruncate(). ^If any 5473** of these pages are pinned, they are implicitly unpinned, meaning that 5474** they can be safely discarded. 5475** 5476** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 5477** All resources associated with the specified cache should be freed. ^After 5478** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 5479** handle invalid, and will not use it with any other sqlite3_pcache_methods 5480** functions. 5481*/ 5482typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 5483struct sqlite3_pcache_methods { 5484 void *pArg; 5485 int (*xInit)(void*); 5486 void (*xShutdown)(void*); 5487 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 5488 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 5489 int (*xPagecount)(sqlite3_pcache*); 5490 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 5491 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 5492 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 5493 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 5494 void (*xDestroy)(sqlite3_pcache*); 5495}; 5496 5497/* 5498** CAPI3REF: Online Backup Object 5499** 5500** The sqlite3_backup object records state information about an ongoing 5501** online backup operation. ^The sqlite3_backup object is created by 5502** a call to [sqlite3_backup_init()] and is destroyed by a call to 5503** [sqlite3_backup_finish()]. 5504** 5505** See Also: [Using the SQLite Online Backup API] 5506*/ 5507typedef struct sqlite3_backup sqlite3_backup; 5508 5509/* 5510** CAPI3REF: Online Backup API. 5511** 5512** The backup API copies the content of one database into another. 5513** It is useful either for creating backups of databases or 5514** for copying in-memory databases to or from persistent files. 5515** 5516** See Also: [Using the SQLite Online Backup API] 5517** 5518** ^Exclusive access is required to the destination database for the 5519** duration of the operation. ^However the source database is only 5520** read-locked while it is actually being read; it is not locked 5521** continuously for the entire backup operation. ^Thus, the backup may be 5522** performed on a live source database without preventing other users from 5523** reading or writing to the source database while the backup is underway. 5524** 5525** ^(To perform a backup operation: 5526** <ol> 5527** <li><b>sqlite3_backup_init()</b> is called once to initialize the 5528** backup, 5529** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 5530** the data between the two databases, and finally 5531** <li><b>sqlite3_backup_finish()</b> is called to release all resources 5532** associated with the backup operation. 5533** </ol>)^ 5534** There should be exactly one call to sqlite3_backup_finish() for each 5535** successful call to sqlite3_backup_init(). 5536** 5537** <b>sqlite3_backup_init()</b> 5538** 5539** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 5540** [database connection] associated with the destination database 5541** and the database name, respectively. 5542** ^The database name is "main" for the main database, "temp" for the 5543** temporary database, or the name specified after the AS keyword in 5544** an [ATTACH] statement for an attached database. 5545** ^The S and M arguments passed to 5546** sqlite3_backup_init(D,N,S,M) identify the [database connection] 5547** and database name of the source database, respectively. 5548** ^The source and destination [database connections] (parameters S and D) 5549** must be different or else sqlite3_backup_init(D,N,S,M) will file with 5550** an error. 5551** 5552** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 5553** returned and an error code and error message are store3d in the 5554** destination [database connection] D. 5555** ^The error code and message for the failed call to sqlite3_backup_init() 5556** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 5557** [sqlite3_errmsg16()] functions. 5558** ^A successful call to sqlite3_backup_init() returns a pointer to an 5559** [sqlite3_backup] object. 5560** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 5561** sqlite3_backup_finish() functions to perform the specified backup 5562** operation. 5563** 5564** <b>sqlite3_backup_step()</b> 5565** 5566** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 5567** the source and destination databases specified by [sqlite3_backup] object B. 5568** ^If N is negative, all remaining source pages are copied. 5569** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 5570** are still more pages to be copied, then the function resturns [SQLITE_OK]. 5571** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 5572** from source to destination, then it returns [SQLITE_DONE]. 5573** ^If an error occurs while running sqlite3_backup_step(B,N), 5574** then an [error code] is returned. ^As well as [SQLITE_OK] and 5575** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 5576** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 5577** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 5578** 5579** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 5580** <ol> 5581** <li> the destination database was opened read-only, or 5582** <li> the destination database is using write-ahead-log journaling 5583** and the destination and source page sizes differ, or 5584** <li> The destination database is an in-memory database and the 5585** destination and source page sizes differ. 5586** </ol>)^ 5587** 5588** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 5589** the [sqlite3_busy_handler | busy-handler function] 5590** is invoked (if one is specified). ^If the 5591** busy-handler returns non-zero before the lock is available, then 5592** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 5593** sqlite3_backup_step() can be retried later. ^If the source 5594** [database connection] 5595** is being used to write to the source database when sqlite3_backup_step() 5596** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 5597** case the call to sqlite3_backup_step() can be retried later on. ^(If 5598** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 5599** [SQLITE_READONLY] is returned, then 5600** there is no point in retrying the call to sqlite3_backup_step(). These 5601** errors are considered fatal.)^ The application must accept 5602** that the backup operation has failed and pass the backup operation handle 5603** to the sqlite3_backup_finish() to release associated resources. 5604** 5605** ^The first call to sqlite3_backup_step() obtains an exclusive lock 5606** on the destination file. ^The exclusive lock is not released until either 5607** sqlite3_backup_finish() is called or the backup operation is complete 5608** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 5609** sqlite3_backup_step() obtains a [shared lock] on the source database that 5610** lasts for the duration of the sqlite3_backup_step() call. 5611** ^Because the source database is not locked between calls to 5612** sqlite3_backup_step(), the source database may be modified mid-way 5613** through the backup process. ^If the source database is modified by an 5614** external process or via a database connection other than the one being 5615** used by the backup operation, then the backup will be automatically 5616** restarted by the next call to sqlite3_backup_step(). ^If the source 5617** database is modified by the using the same database connection as is used 5618** by the backup operation, then the backup database is automatically 5619** updated at the same time. 5620** 5621** <b>sqlite3_backup_finish()</b> 5622** 5623** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 5624** application wishes to abandon the backup operation, the application 5625** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 5626** ^The sqlite3_backup_finish() interfaces releases all 5627** resources associated with the [sqlite3_backup] object. 5628** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 5629** active write-transaction on the destination database is rolled back. 5630** The [sqlite3_backup] object is invalid 5631** and may not be used following a call to sqlite3_backup_finish(). 5632** 5633** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 5634** sqlite3_backup_step() errors occurred, regardless or whether or not 5635** sqlite3_backup_step() completed. 5636** ^If an out-of-memory condition or IO error occurred during any prior 5637** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 5638** sqlite3_backup_finish() returns the corresponding [error code]. 5639** 5640** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 5641** is not a permanent error and does not affect the return value of 5642** sqlite3_backup_finish(). 5643** 5644** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b> 5645** 5646** ^Each call to sqlite3_backup_step() sets two values inside 5647** the [sqlite3_backup] object: the number of pages still to be backed 5648** up and the total number of pages in the source databae file. 5649** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 5650** retrieve these two values, respectively. 5651** 5652** ^The values returned by these functions are only updated by 5653** sqlite3_backup_step(). ^If the source database is modified during a backup 5654** operation, then the values are not updated to account for any extra 5655** pages that need to be updated or the size of the source database file 5656** changing. 5657** 5658** <b>Concurrent Usage of Database Handles</b> 5659** 5660** ^The source [database connection] may be used by the application for other 5661** purposes while a backup operation is underway or being initialized. 5662** ^If SQLite is compiled and configured to support threadsafe database 5663** connections, then the source database connection may be used concurrently 5664** from within other threads. 5665** 5666** However, the application must guarantee that the destination 5667** [database connection] is not passed to any other API (by any thread) after 5668** sqlite3_backup_init() is called and before the corresponding call to 5669** sqlite3_backup_finish(). SQLite does not currently check to see 5670** if the application incorrectly accesses the destination [database connection] 5671** and so no error code is reported, but the operations may malfunction 5672** nevertheless. Use of the destination database connection while a 5673** backup is in progress might also also cause a mutex deadlock. 5674** 5675** If running in [shared cache mode], the application must 5676** guarantee that the shared cache used by the destination database 5677** is not accessed while the backup is running. In practice this means 5678** that the application must guarantee that the disk file being 5679** backed up to is not accessed by any connection within the process, 5680** not just the specific connection that was passed to sqlite3_backup_init(). 5681** 5682** The [sqlite3_backup] object itself is partially threadsafe. Multiple 5683** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 5684** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 5685** APIs are not strictly speaking threadsafe. If they are invoked at the 5686** same time as another thread is invoking sqlite3_backup_step() it is 5687** possible that they return invalid values. 5688*/ 5689sqlite3_backup *sqlite3_backup_init( 5690 sqlite3 *pDest, /* Destination database handle */ 5691 const char *zDestName, /* Destination database name */ 5692 sqlite3 *pSource, /* Source database handle */ 5693 const char *zSourceName /* Source database name */ 5694); 5695int sqlite3_backup_step(sqlite3_backup *p, int nPage); 5696int sqlite3_backup_finish(sqlite3_backup *p); 5697int sqlite3_backup_remaining(sqlite3_backup *p); 5698int sqlite3_backup_pagecount(sqlite3_backup *p); 5699 5700/* 5701** CAPI3REF: Unlock Notification 5702** 5703** ^When running in shared-cache mode, a database operation may fail with 5704** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 5705** individual tables within the shared-cache cannot be obtained. See 5706** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 5707** ^This API may be used to register a callback that SQLite will invoke 5708** when the connection currently holding the required lock relinquishes it. 5709** ^This API is only available if the library was compiled with the 5710** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 5711** 5712** See Also: [Using the SQLite Unlock Notification Feature]. 5713** 5714** ^Shared-cache locks are released when a database connection concludes 5715** its current transaction, either by committing it or rolling it back. 5716** 5717** ^When a connection (known as the blocked connection) fails to obtain a 5718** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 5719** identity of the database connection (the blocking connection) that 5720** has locked the required resource is stored internally. ^After an 5721** application receives an SQLITE_LOCKED error, it may call the 5722** sqlite3_unlock_notify() method with the blocked connection handle as 5723** the first argument to register for a callback that will be invoked 5724** when the blocking connections current transaction is concluded. ^The 5725** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 5726** call that concludes the blocking connections transaction. 5727** 5728** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 5729** there is a chance that the blocking connection will have already 5730** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 5731** If this happens, then the specified callback is invoked immediately, 5732** from within the call to sqlite3_unlock_notify().)^ 5733** 5734** ^If the blocked connection is attempting to obtain a write-lock on a 5735** shared-cache table, and more than one other connection currently holds 5736** a read-lock on the same table, then SQLite arbitrarily selects one of 5737** the other connections to use as the blocking connection. 5738** 5739** ^(There may be at most one unlock-notify callback registered by a 5740** blocked connection. If sqlite3_unlock_notify() is called when the 5741** blocked connection already has a registered unlock-notify callback, 5742** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 5743** called with a NULL pointer as its second argument, then any existing 5744** unlock-notify callback is cancelled. ^The blocked connections 5745** unlock-notify callback may also be canceled by closing the blocked 5746** connection using [sqlite3_close()]. 5747** 5748** The unlock-notify callback is not reentrant. If an application invokes 5749** any sqlite3_xxx API functions from within an unlock-notify callback, a 5750** crash or deadlock may be the result. 5751** 5752** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 5753** returns SQLITE_OK. 5754** 5755** <b>Callback Invocation Details</b> 5756** 5757** When an unlock-notify callback is registered, the application provides a 5758** single void* pointer that is passed to the callback when it is invoked. 5759** However, the signature of the callback function allows SQLite to pass 5760** it an array of void* context pointers. The first argument passed to 5761** an unlock-notify callback is a pointer to an array of void* pointers, 5762** and the second is the number of entries in the array. 5763** 5764** When a blocking connections transaction is concluded, there may be 5765** more than one blocked connection that has registered for an unlock-notify 5766** callback. ^If two or more such blocked connections have specified the 5767** same callback function, then instead of invoking the callback function 5768** multiple times, it is invoked once with the set of void* context pointers 5769** specified by the blocked connections bundled together into an array. 5770** This gives the application an opportunity to prioritize any actions 5771** related to the set of unblocked database connections. 5772** 5773** <b>Deadlock Detection</b> 5774** 5775** Assuming that after registering for an unlock-notify callback a 5776** database waits for the callback to be issued before taking any further 5777** action (a reasonable assumption), then using this API may cause the 5778** application to deadlock. For example, if connection X is waiting for 5779** connection Y's transaction to be concluded, and similarly connection 5780** Y is waiting on connection X's transaction, then neither connection 5781** will proceed and the system may remain deadlocked indefinitely. 5782** 5783** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 5784** detection. ^If a given call to sqlite3_unlock_notify() would put the 5785** system in a deadlocked state, then SQLITE_LOCKED is returned and no 5786** unlock-notify callback is registered. The system is said to be in 5787** a deadlocked state if connection A has registered for an unlock-notify 5788** callback on the conclusion of connection B's transaction, and connection 5789** B has itself registered for an unlock-notify callback when connection 5790** A's transaction is concluded. ^Indirect deadlock is also detected, so 5791** the system is also considered to be deadlocked if connection B has 5792** registered for an unlock-notify callback on the conclusion of connection 5793** C's transaction, where connection C is waiting on connection A. ^Any 5794** number of levels of indirection are allowed. 5795** 5796** <b>The "DROP TABLE" Exception</b> 5797** 5798** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 5799** always appropriate to call sqlite3_unlock_notify(). There is however, 5800** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 5801** SQLite checks if there are any currently executing SELECT statements 5802** that belong to the same connection. If there are, SQLITE_LOCKED is 5803** returned. In this case there is no "blocking connection", so invoking 5804** sqlite3_unlock_notify() results in the unlock-notify callback being 5805** invoked immediately. If the application then re-attempts the "DROP TABLE" 5806** or "DROP INDEX" query, an infinite loop might be the result. 5807** 5808** One way around this problem is to check the extended error code returned 5809** by an sqlite3_step() call. ^(If there is a blocking connection, then the 5810** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 5811** the special "DROP TABLE/INDEX" case, the extended error code is just 5812** SQLITE_LOCKED.)^ 5813*/ 5814int sqlite3_unlock_notify( 5815 sqlite3 *pBlocked, /* Waiting connection */ 5816 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 5817 void *pNotifyArg /* Argument to pass to xNotify */ 5818); 5819 5820 5821/* 5822** CAPI3REF: String Comparison 5823** 5824** ^The [sqlite3_strnicmp()] API allows applications and extensions to 5825** compare the contents of two buffers containing UTF-8 strings in a 5826** case-indendent fashion, using the same definition of case independence 5827** that SQLite uses internally when comparing identifiers. 5828*/ 5829int sqlite3_strnicmp(const char *, const char *, int); 5830 5831/* 5832** CAPI3REF: Error Logging Interface 5833** 5834** ^The [sqlite3_log()] interface writes a message into the error log 5835** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 5836** ^If logging is enabled, the zFormat string and subsequent arguments are 5837** used with [sqlite3_snprintf()] to generate the final output string. 5838** 5839** The sqlite3_log() interface is intended for use by extensions such as 5840** virtual tables, collating functions, and SQL functions. While there is 5841** nothing to prevent an application from calling sqlite3_log(), doing so 5842** is considered bad form. 5843** 5844** The zFormat string must not be NULL. 5845** 5846** To avoid deadlocks and other threading problems, the sqlite3_log() routine 5847** will not use dynamically allocated memory. The log message is stored in 5848** a fixed-length buffer on the stack. If the log message is longer than 5849** a few hundred characters, it will be truncated to the length of the 5850** buffer. 5851*/ 5852void sqlite3_log(int iErrCode, const char *zFormat, ...); 5853 5854/* 5855** CAPI3REF: Write-Ahead Log Commit Hook 5856** 5857** ^The [sqlite3_wal_hook()] function is used to register a callback that 5858** will be invoked each time a database connection commits data to a 5859** [write-ahead log] (i.e. whenever a transaction is committed in 5860** [journal_mode | journal_mode=WAL mode]). 5861** 5862** ^The callback is invoked by SQLite after the commit has taken place and 5863** the associated write-lock on the database released, so the implementation 5864** may read, write or [checkpoint] the database as required. 5865** 5866** ^The first parameter passed to the callback function when it is invoked 5867** is a copy of the third parameter passed to sqlite3_wal_hook() when 5868** registering the callback. ^The second is a copy of the database handle. 5869** ^The third parameter is the name of the database that was written to - 5870** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 5871** is the number of pages currently in the write-ahead log file, 5872** including those that were just committed. 5873** 5874** The callback function should normally return [SQLITE_OK]. ^If an error 5875** code is returned, that error will propagate back up through the 5876** SQLite code base to cause the statement that provoked the callback 5877** to report an error, though the commit will have still occurred. If the 5878** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 5879** that does not correspond to any valid SQLite error code, the results 5880** are undefined. 5881** 5882** A single database handle may have at most a single write-ahead log callback 5883** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 5884** previously registered write-ahead log callback. ^Note that the 5885** [sqlite3_wal_autocheckpoint()] interface and the 5886** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 5887** those overwrite any prior [sqlite3_wal_hook()] settings. 5888*/ 5889void *sqlite3_wal_hook( 5890 sqlite3*, 5891 int(*)(void *,sqlite3*,const char*,int), 5892 void* 5893); 5894 5895/* 5896** CAPI3REF: Configure an auto-checkpoint 5897** 5898** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 5899** [sqlite3_wal_hook()] that causes any database on [database connection] D 5900** to automatically [checkpoint] 5901** after committing a transaction if there are N or 5902** more frames in the [write-ahead log] file. ^Passing zero or 5903** a negative value as the nFrame parameter disables automatic 5904** checkpoints entirely. 5905** 5906** ^The callback registered by this function replaces any existing callback 5907** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 5908** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 5909** configured by this function. 5910** 5911** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 5912** from SQL. 5913** 5914** ^Every new [database connection] defaults to having the auto-checkpoint 5915** enabled with a threshold of 1000 pages. The use of this interface 5916** is only necessary if the default setting is found to be suboptimal 5917** for a particular application. 5918*/ 5919int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 5920 5921/* 5922** CAPI3REF: Checkpoint a database 5923** 5924** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 5925** on [database connection] D to be [checkpointed]. ^If X is NULL or an 5926** empty string, then a checkpoint is run on all databases of 5927** connection D. ^If the database connection D is not in 5928** [WAL | write-ahead log mode] then this interface is a harmless no-op. 5929** 5930** ^The [wal_checkpoint pragma] can be used to invoke this interface 5931** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 5932** [wal_autocheckpoint pragma] can be used to cause this interface to be 5933** run whenever the WAL reaches a certain size threshold. 5934*/ 5935int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 5936 5937/* 5938** Undo the hack that converts floating point types to integer for 5939** builds on processors without floating point support. 5940*/ 5941#ifdef SQLITE_OMIT_FLOATING_POINT 5942# undef double 5943#endif 5944 5945#ifdef __cplusplus 5946} /* End of the 'extern "C"' block */ 5947#endif 5948#endif 5949