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 supposed 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** Provide the ability to override linkage features of the interface. 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51#ifndef SQLITE_API 52# define SQLITE_API 53#endif 54#ifndef SQLITE_CDECL 55# define SQLITE_CDECL 56#endif 57#ifndef SQLITE_APICALL 58# define SQLITE_APICALL 59#endif 60#ifndef SQLITE_STDCALL 61# define SQLITE_STDCALL SQLITE_APICALL 62#endif 63#ifndef SQLITE_CALLBACK 64# define SQLITE_CALLBACK 65#endif 66#ifndef SQLITE_SYSAPI 67# define SQLITE_SYSAPI 68#endif 69 70/* 71** These no-op macros are used in front of interfaces to mark those 72** interfaces as either deprecated or experimental. New applications 73** should not use deprecated interfaces - they are supported for backwards 74** compatibility only. Application writers should be aware that 75** experimental interfaces are subject to change in point releases. 76** 77** These macros used to resolve to various kinds of compiler magic that 78** would generate warning messages when they were used. But that 79** compiler magic ended up generating such a flurry of bug reports 80** that we have taken it all out and gone back to using simple 81** noop macros. 82*/ 83#define SQLITE_DEPRECATED 84#define SQLITE_EXPERIMENTAL 85 86/* 87** Ensure these symbols were not defined by some previous header file. 88*/ 89#ifdef SQLITE_VERSION 90# undef SQLITE_VERSION 91#endif 92#ifdef SQLITE_VERSION_NUMBER 93# undef SQLITE_VERSION_NUMBER 94#endif 95 96/* 97** CAPI3REF: Compile-Time Library Version Numbers 98** 99** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 100** evaluates to a string literal that is the SQLite version in the 101** format "X.Y.Z" where X is the major version number (always 3 for 102** SQLite3) and Y is the minor version number and Z is the release number.)^ 103** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 104** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 105** numbers used in [SQLITE_VERSION].)^ 106** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 107** be larger than the release from which it is derived. Either Y will 108** be held constant and Z will be incremented or else Y will be incremented 109** and Z will be reset to zero. 110** 111** Since [version 3.6.18] ([dateof:3.6.18]), 112** SQLite source code has been stored in the 113** <a href="http://www.fossil-scm.org/">Fossil configuration management 114** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 115** a string which identifies a particular check-in of SQLite 116** within its configuration management system. ^The SQLITE_SOURCE_ID 117** string contains the date and time of the check-in (UTC) and an SHA1 118** hash of the entire source tree. 119** 120** See also: [sqlite3_libversion()], 121** [sqlite3_libversion_number()], [sqlite3_sourceid()], 122** [sqlite_version()] and [sqlite_source_id()]. 123*/ 124#define SQLITE_VERSION "--VERS--" 125#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 126#define SQLITE_SOURCE_ID "--SOURCE-ID--" 127 128/* 129** CAPI3REF: Run-Time Library Version Numbers 130** KEYWORDS: sqlite3_version, sqlite3_sourceid 131** 132** These interfaces provide the same information as the [SQLITE_VERSION], 133** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 134** but are associated with the library instead of the header file. ^(Cautious 135** programmers might include assert() statements in their application to 136** verify that values returned by these interfaces match the macros in 137** the header, and thus ensure that the application is 138** compiled with matching library and header files. 139** 140** <blockquote><pre> 141** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 142** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 143** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 144** </pre></blockquote>)^ 145** 146** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 147** macro. ^The sqlite3_libversion() function returns a pointer to the 148** to the sqlite3_version[] string constant. The sqlite3_libversion() 149** function is provided for use in DLLs since DLL users usually do not have 150** direct access to string constants within the DLL. ^The 151** sqlite3_libversion_number() function returns an integer equal to 152** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 153** a pointer to a string constant whose value is the same as the 154** [SQLITE_SOURCE_ID] C preprocessor macro. 155** 156** See also: [sqlite_version()] and [sqlite_source_id()]. 157*/ 158SQLITE_EXTERN const char sqlite3_version[]; 159const char *sqlite3_libversion(void); 160const char *sqlite3_sourceid(void); 161int sqlite3_libversion_number(void); 162 163/* 164** CAPI3REF: Run-Time Library Compilation Options Diagnostics 165** 166** ^The sqlite3_compileoption_used() function returns 0 or 1 167** indicating whether the specified option was defined at 168** compile time. ^The SQLITE_ prefix may be omitted from the 169** option name passed to sqlite3_compileoption_used(). 170** 171** ^The sqlite3_compileoption_get() function allows iterating 172** over the list of options that were defined at compile time by 173** returning the N-th compile time option string. ^If N is out of range, 174** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 175** prefix is omitted from any strings returned by 176** sqlite3_compileoption_get(). 177** 178** ^Support for the diagnostic functions sqlite3_compileoption_used() 179** and sqlite3_compileoption_get() may be omitted by specifying the 180** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 181** 182** See also: SQL functions [sqlite_compileoption_used()] and 183** [sqlite_compileoption_get()] and the [compile_options pragma]. 184*/ 185#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 186int sqlite3_compileoption_used(const char *zOptName); 187const char *sqlite3_compileoption_get(int N); 188#endif 189 190/* 191** CAPI3REF: Test To See If The Library Is Threadsafe 192** 193** ^The sqlite3_threadsafe() function returns zero if and only if 194** SQLite was compiled with mutexing code omitted due to the 195** [SQLITE_THREADSAFE] compile-time option being set to 0. 196** 197** SQLite can be compiled with or without mutexes. When 198** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 199** are enabled and SQLite is threadsafe. When the 200** [SQLITE_THREADSAFE] macro is 0, 201** the mutexes are omitted. Without the mutexes, it is not safe 202** to use SQLite concurrently from more than one thread. 203** 204** Enabling mutexes incurs a measurable performance penalty. 205** So if speed is of utmost importance, it makes sense to disable 206** the mutexes. But for maximum safety, mutexes should be enabled. 207** ^The default behavior is for mutexes to be enabled. 208** 209** This interface can be used by an application to make sure that the 210** version of SQLite that it is linking against was compiled with 211** the desired setting of the [SQLITE_THREADSAFE] macro. 212** 213** This interface only reports on the compile-time mutex setting 214** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 215** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 216** can be fully or partially disabled using a call to [sqlite3_config()] 217** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 218** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the 219** sqlite3_threadsafe() function shows only the compile-time setting of 220** thread safety, not any run-time changes to that setting made by 221** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 222** is unchanged by calls to sqlite3_config().)^ 223** 224** See the [threading mode] documentation for additional information. 225*/ 226int sqlite3_threadsafe(void); 227 228/* 229** CAPI3REF: Database Connection Handle 230** KEYWORDS: {database connection} {database connections} 231** 232** Each open SQLite database is represented by a pointer to an instance of 233** the opaque structure named "sqlite3". It is useful to think of an sqlite3 234** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 235** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 236** and [sqlite3_close_v2()] are its destructors. There are many other 237** interfaces (such as 238** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 239** [sqlite3_busy_timeout()] to name but three) that are methods on an 240** sqlite3 object. 241*/ 242typedef struct sqlite3 sqlite3; 243 244/* 245** CAPI3REF: 64-Bit Integer Types 246** KEYWORDS: sqlite_int64 sqlite_uint64 247** 248** Because there is no cross-platform way to specify 64-bit integer types 249** SQLite includes typedefs for 64-bit signed and unsigned integers. 250** 251** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 252** The sqlite_int64 and sqlite_uint64 types are supported for backwards 253** compatibility only. 254** 255** ^The sqlite3_int64 and sqlite_int64 types can store integer values 256** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 257** sqlite3_uint64 and sqlite_uint64 types can store integer values 258** between 0 and +18446744073709551615 inclusive. 259*/ 260#ifdef SQLITE_INT64_TYPE 261 typedef SQLITE_INT64_TYPE sqlite_int64; 262 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 263#elif defined(_MSC_VER) || defined(__BORLANDC__) 264 typedef __int64 sqlite_int64; 265 typedef unsigned __int64 sqlite_uint64; 266#else 267 typedef long long int sqlite_int64; 268 typedef unsigned long long int sqlite_uint64; 269#endif 270typedef sqlite_int64 sqlite3_int64; 271typedef sqlite_uint64 sqlite3_uint64; 272 273/* 274** If compiling for a processor that lacks floating point support, 275** substitute integer for floating-point. 276*/ 277#ifdef SQLITE_OMIT_FLOATING_POINT 278# define double sqlite3_int64 279#endif 280 281/* 282** CAPI3REF: Closing A Database Connection 283** DESTRUCTOR: sqlite3 284** 285** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 286** for the [sqlite3] object. 287** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 288** the [sqlite3] object is successfully destroyed and all associated 289** resources are deallocated. 290** 291** ^If the database connection is associated with unfinalized prepared 292** statements or unfinished sqlite3_backup objects then sqlite3_close() 293** will leave the database connection open and return [SQLITE_BUSY]. 294** ^If sqlite3_close_v2() is called with unfinalized prepared statements 295** and/or unfinished sqlite3_backups, then the database connection becomes 296** an unusable "zombie" which will automatically be deallocated when the 297** last prepared statement is finalized or the last sqlite3_backup is 298** finished. The sqlite3_close_v2() interface is intended for use with 299** host languages that are garbage collected, and where the order in which 300** destructors are called is arbitrary. 301** 302** Applications should [sqlite3_finalize | finalize] all [prepared statements], 303** [sqlite3_blob_close | close] all [BLOB handles], and 304** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 305** with the [sqlite3] object prior to attempting to close the object. ^If 306** sqlite3_close_v2() is called on a [database connection] that still has 307** outstanding [prepared statements], [BLOB handles], and/or 308** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation 309** of resources is deferred until all [prepared statements], [BLOB handles], 310** and [sqlite3_backup] objects are also destroyed. 311** 312** ^If an [sqlite3] object is destroyed while a transaction is open, 313** the transaction is automatically rolled back. 314** 315** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 316** must be either a NULL 317** pointer or an [sqlite3] object pointer obtained 318** from [sqlite3_open()], [sqlite3_open16()], or 319** [sqlite3_open_v2()], and not previously closed. 320** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 321** argument is a harmless no-op. 322*/ 323int sqlite3_close(sqlite3*); 324int sqlite3_close_v2(sqlite3*); 325 326/* 327** The type for a callback function. 328** This is legacy and deprecated. It is included for historical 329** compatibility and is not documented. 330*/ 331typedef int (*sqlite3_callback)(void*,int,char**, char**); 332 333/* 334** CAPI3REF: One-Step Query Execution Interface 335** METHOD: sqlite3 336** 337** The sqlite3_exec() interface is a convenience wrapper around 338** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 339** that allows an application to run multiple statements of SQL 340** without having to use a lot of C code. 341** 342** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 343** semicolon-separate SQL statements passed into its 2nd argument, 344** in the context of the [database connection] passed in as its 1st 345** argument. ^If the callback function of the 3rd argument to 346** sqlite3_exec() is not NULL, then it is invoked for each result row 347** coming out of the evaluated SQL statements. ^The 4th argument to 348** sqlite3_exec() is relayed through to the 1st argument of each 349** callback invocation. ^If the callback pointer to sqlite3_exec() 350** is NULL, then no callback is ever invoked and result rows are 351** ignored. 352** 353** ^If an error occurs while evaluating the SQL statements passed into 354** sqlite3_exec(), then execution of the current statement stops and 355** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 356** is not NULL then any error message is written into memory obtained 357** from [sqlite3_malloc()] and passed back through the 5th parameter. 358** To avoid memory leaks, the application should invoke [sqlite3_free()] 359** on error message strings returned through the 5th parameter of 360** sqlite3_exec() after the error message string is no longer needed. 361** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 362** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 363** NULL before returning. 364** 365** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 366** routine returns SQLITE_ABORT without invoking the callback again and 367** without running any subsequent SQL statements. 368** 369** ^The 2nd argument to the sqlite3_exec() callback function is the 370** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 371** callback is an array of pointers to strings obtained as if from 372** [sqlite3_column_text()], one for each column. ^If an element of a 373** result row is NULL then the corresponding string pointer for the 374** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 375** sqlite3_exec() callback is an array of pointers to strings where each 376** entry represents the name of corresponding result column as obtained 377** from [sqlite3_column_name()]. 378** 379** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 380** to an empty string, or a pointer that contains only whitespace and/or 381** SQL comments, then no SQL statements are evaluated and the database 382** is not changed. 383** 384** Restrictions: 385** 386** <ul> 387** <li> The application must ensure that the 1st parameter to sqlite3_exec() 388** is a valid and open [database connection]. 389** <li> The application must not close the [database connection] specified by 390** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 391** <li> The application must not modify the SQL statement text passed into 392** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 393** </ul> 394*/ 395int sqlite3_exec( 396 sqlite3*, /* An open database */ 397 const char *sql, /* SQL to be evaluated */ 398 int (*callback)(void*,int,char**,char**), /* Callback function */ 399 void *, /* 1st argument to callback */ 400 char **errmsg /* Error msg written here */ 401); 402 403/* 404** CAPI3REF: Result Codes 405** KEYWORDS: {result code definitions} 406** 407** Many SQLite functions return an integer result code from the set shown 408** here in order to indicate success or failure. 409** 410** New error codes may be added in future versions of SQLite. 411** 412** See also: [extended result code definitions] 413*/ 414#define SQLITE_OK 0 /* Successful result */ 415/* beginning-of-error-codes */ 416#define SQLITE_ERROR 1 /* SQL error or missing database */ 417#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 418#define SQLITE_PERM 3 /* Access permission denied */ 419#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 420#define SQLITE_BUSY 5 /* The database file is locked */ 421#define SQLITE_LOCKED 6 /* A table in the database is locked */ 422#define SQLITE_NOMEM 7 /* A malloc() failed */ 423#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 424#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 425#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 426#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 427#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 428#define SQLITE_FULL 13 /* Insertion failed because database is full */ 429#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 430#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 431#define SQLITE_EMPTY 16 /* Database is empty */ 432#define SQLITE_SCHEMA 17 /* The database schema changed */ 433#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 434#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 435#define SQLITE_MISMATCH 20 /* Data type mismatch */ 436#define SQLITE_MISUSE 21 /* Library used incorrectly */ 437#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 438#define SQLITE_AUTH 23 /* Authorization denied */ 439#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 440#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 441#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 442#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 443#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 444#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 445#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 446/* end-of-error-codes */ 447 448/* 449** CAPI3REF: Extended Result Codes 450** KEYWORDS: {extended result code definitions} 451** 452** In its default configuration, SQLite API routines return one of 30 integer 453** [result codes]. However, experience has shown that many of 454** these result codes are too coarse-grained. They do not provide as 455** much information about problems as programmers might like. In an effort to 456** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8] 457** and later) include 458** support for additional result codes that provide more detailed information 459** about errors. These [extended result codes] are enabled or disabled 460** on a per database connection basis using the 461** [sqlite3_extended_result_codes()] API. Or, the extended code for 462** the most recent error can be obtained using 463** [sqlite3_extended_errcode()]. 464*/ 465#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 466#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 467#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 468#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 469#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 470#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 471#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 472#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 473#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 474#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 475#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 476#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 477#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 478#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 479#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 480#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 481#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 482#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 483#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 484#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 485#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 486#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 487#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 488#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 489#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 490#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 491#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8)) 492#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8)) 493#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 494#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 495#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 496#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 497#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 498#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 499#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 500#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 501#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 502#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 503#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 504#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 505#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 506#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 507#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 508#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 509#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 510#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 511#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 512#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 513#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 514#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 515#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 516#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 517#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 518#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 519#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 520#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8)) 521 522/* 523** CAPI3REF: Flags For File Open Operations 524** 525** These bit values are intended for use in the 526** 3rd parameter to the [sqlite3_open_v2()] interface and 527** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 528*/ 529#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 530#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 531#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 532#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 533#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 534#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 535#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 536#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 537#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 538#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 539#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 540#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 541#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 542#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 543#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 544#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 545#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 546#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 547#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 548#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 549 550/* Reserved: 0x00F00000 */ 551 552/* 553** CAPI3REF: Device Characteristics 554** 555** The xDeviceCharacteristics method of the [sqlite3_io_methods] 556** object returns an integer which is a vector of these 557** bit values expressing I/O characteristics of the mass storage 558** device that holds the file that the [sqlite3_io_methods] 559** refers to. 560** 561** The SQLITE_IOCAP_ATOMIC property means that all writes of 562** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 563** mean that writes of blocks that are nnn bytes in size and 564** are aligned to an address which is an integer multiple of 565** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 566** that when data is appended to a file, the data is appended 567** first then the size of the file is extended, never the other 568** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 569** information is written to disk in the same order as calls 570** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 571** after reboot following a crash or power loss, the only bytes in a 572** file that were written at the application level might have changed 573** and that adjacent bytes, even bytes within the same sector are 574** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 575** flag indicate that a file cannot be deleted when open. The 576** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 577** read-only media and cannot be changed even by processes with 578** elevated privileges. 579*/ 580#define SQLITE_IOCAP_ATOMIC 0x00000001 581#define SQLITE_IOCAP_ATOMIC512 0x00000002 582#define SQLITE_IOCAP_ATOMIC1K 0x00000004 583#define SQLITE_IOCAP_ATOMIC2K 0x00000008 584#define SQLITE_IOCAP_ATOMIC4K 0x00000010 585#define SQLITE_IOCAP_ATOMIC8K 0x00000020 586#define SQLITE_IOCAP_ATOMIC16K 0x00000040 587#define SQLITE_IOCAP_ATOMIC32K 0x00000080 588#define SQLITE_IOCAP_ATOMIC64K 0x00000100 589#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 590#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 591#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 592#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 593#define SQLITE_IOCAP_IMMUTABLE 0x00002000 594 595/* 596** CAPI3REF: File Locking Levels 597** 598** SQLite uses one of these integer values as the second 599** argument to calls it makes to the xLock() and xUnlock() methods 600** of an [sqlite3_io_methods] object. 601*/ 602#define SQLITE_LOCK_NONE 0 603#define SQLITE_LOCK_SHARED 1 604#define SQLITE_LOCK_RESERVED 2 605#define SQLITE_LOCK_PENDING 3 606#define SQLITE_LOCK_EXCLUSIVE 4 607 608/* 609** CAPI3REF: Synchronization Type Flags 610** 611** When SQLite invokes the xSync() method of an 612** [sqlite3_io_methods] object it uses a combination of 613** these integer values as the second argument. 614** 615** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 616** sync operation only needs to flush data to mass storage. Inode 617** information need not be flushed. If the lower four bits of the flag 618** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 619** If the lower four bits equal SQLITE_SYNC_FULL, that means 620** to use Mac OS X style fullsync instead of fsync(). 621** 622** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 623** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 624** settings. The [synchronous pragma] determines when calls to the 625** xSync VFS method occur and applies uniformly across all platforms. 626** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 627** energetic or rigorous or forceful the sync operations are and 628** only make a difference on Mac OSX for the default SQLite code. 629** (Third-party VFS implementations might also make the distinction 630** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 631** operating systems natively supported by SQLite, only Mac OSX 632** cares about the difference.) 633*/ 634#define SQLITE_SYNC_NORMAL 0x00002 635#define SQLITE_SYNC_FULL 0x00003 636#define SQLITE_SYNC_DATAONLY 0x00010 637 638/* 639** CAPI3REF: OS Interface Open File Handle 640** 641** An [sqlite3_file] object represents an open file in the 642** [sqlite3_vfs | OS interface layer]. Individual OS interface 643** implementations will 644** want to subclass this object by appending additional fields 645** for their own use. The pMethods entry is a pointer to an 646** [sqlite3_io_methods] object that defines methods for performing 647** I/O operations on the open file. 648*/ 649typedef struct sqlite3_file sqlite3_file; 650struct sqlite3_file { 651 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 652}; 653 654/* 655** CAPI3REF: OS Interface File Virtual Methods Object 656** 657** Every file opened by the [sqlite3_vfs.xOpen] method populates an 658** [sqlite3_file] object (or, more commonly, a subclass of the 659** [sqlite3_file] object) with a pointer to an instance of this object. 660** This object defines the methods used to perform various operations 661** against the open file represented by the [sqlite3_file] object. 662** 663** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 664** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 665** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 666** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 667** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 668** to NULL. 669** 670** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 671** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 672** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 673** flag may be ORed in to indicate that only the data of the file 674** and not its inode needs to be synced. 675** 676** The integer values to xLock() and xUnlock() are one of 677** <ul> 678** <li> [SQLITE_LOCK_NONE], 679** <li> [SQLITE_LOCK_SHARED], 680** <li> [SQLITE_LOCK_RESERVED], 681** <li> [SQLITE_LOCK_PENDING], or 682** <li> [SQLITE_LOCK_EXCLUSIVE]. 683** </ul> 684** xLock() increases the lock. xUnlock() decreases the lock. 685** The xCheckReservedLock() method checks whether any database connection, 686** either in this process or in some other process, is holding a RESERVED, 687** PENDING, or EXCLUSIVE lock on the file. It returns true 688** if such a lock exists and false otherwise. 689** 690** The xFileControl() method is a generic interface that allows custom 691** VFS implementations to directly control an open file using the 692** [sqlite3_file_control()] interface. The second "op" argument is an 693** integer opcode. The third argument is a generic pointer intended to 694** point to a structure that may contain arguments or space in which to 695** write return values. Potential uses for xFileControl() might be 696** functions to enable blocking locks with timeouts, to change the 697** locking strategy (for example to use dot-file locks), to inquire 698** about the status of a lock, or to break stale locks. The SQLite 699** core reserves all opcodes less than 100 for its own use. 700** A [file control opcodes | list of opcodes] less than 100 is available. 701** Applications that define a custom xFileControl method should use opcodes 702** greater than 100 to avoid conflicts. VFS implementations should 703** return [SQLITE_NOTFOUND] for file control opcodes that they do not 704** recognize. 705** 706** The xSectorSize() method returns the sector size of the 707** device that underlies the file. The sector size is the 708** minimum write that can be performed without disturbing 709** other bytes in the file. The xDeviceCharacteristics() 710** method returns a bit vector describing behaviors of the 711** underlying device: 712** 713** <ul> 714** <li> [SQLITE_IOCAP_ATOMIC] 715** <li> [SQLITE_IOCAP_ATOMIC512] 716** <li> [SQLITE_IOCAP_ATOMIC1K] 717** <li> [SQLITE_IOCAP_ATOMIC2K] 718** <li> [SQLITE_IOCAP_ATOMIC4K] 719** <li> [SQLITE_IOCAP_ATOMIC8K] 720** <li> [SQLITE_IOCAP_ATOMIC16K] 721** <li> [SQLITE_IOCAP_ATOMIC32K] 722** <li> [SQLITE_IOCAP_ATOMIC64K] 723** <li> [SQLITE_IOCAP_SAFE_APPEND] 724** <li> [SQLITE_IOCAP_SEQUENTIAL] 725** </ul> 726** 727** The SQLITE_IOCAP_ATOMIC property means that all writes of 728** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 729** mean that writes of blocks that are nnn bytes in size and 730** are aligned to an address which is an integer multiple of 731** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 732** that when data is appended to a file, the data is appended 733** first then the size of the file is extended, never the other 734** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 735** information is written to disk in the same order as calls 736** to xWrite(). 737** 738** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 739** in the unread portions of the buffer with zeros. A VFS that 740** fails to zero-fill short reads might seem to work. However, 741** failure to zero-fill short reads will eventually lead to 742** database corruption. 743*/ 744typedef struct sqlite3_io_methods sqlite3_io_methods; 745struct sqlite3_io_methods { 746 int iVersion; 747 int (*xClose)(sqlite3_file*); 748 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 749 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 750 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 751 int (*xSync)(sqlite3_file*, int flags); 752 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 753 int (*xLock)(sqlite3_file*, int); 754 int (*xUnlock)(sqlite3_file*, int); 755 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 756 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 757 int (*xSectorSize)(sqlite3_file*); 758 int (*xDeviceCharacteristics)(sqlite3_file*); 759 /* Methods above are valid for version 1 */ 760 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 761 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 762 void (*xShmBarrier)(sqlite3_file*); 763 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 764 /* Methods above are valid for version 2 */ 765 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 766 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 767 /* Methods above are valid for version 3 */ 768 /* Additional methods may be added in future releases */ 769}; 770 771/* 772** CAPI3REF: Standard File Control Opcodes 773** KEYWORDS: {file control opcodes} {file control opcode} 774** 775** These integer constants are opcodes for the xFileControl method 776** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 777** interface. 778** 779** <ul> 780** <li>[[SQLITE_FCNTL_LOCKSTATE]] 781** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 782** opcode causes the xFileControl method to write the current state of 783** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 784** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 785** into an integer that the pArg argument points to. This capability 786** is used during testing and is only available when the SQLITE_TEST 787** compile-time option is used. 788** 789** <li>[[SQLITE_FCNTL_SIZE_HINT]] 790** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 791** layer a hint of how large the database file will grow to be during the 792** current transaction. This hint is not guaranteed to be accurate but it 793** is often close. The underlying VFS might choose to preallocate database 794** file space based on this hint in order to help writes to the database 795** file run faster. 796** 797** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 798** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 799** extends and truncates the database file in chunks of a size specified 800** by the user. The fourth argument to [sqlite3_file_control()] should 801** point to an integer (type int) containing the new chunk-size to use 802** for the nominated database. Allocating database file space in large 803** chunks (say 1MB at a time), may reduce file-system fragmentation and 804** improve performance on some systems. 805** 806** <li>[[SQLITE_FCNTL_FILE_POINTER]] 807** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 808** to the [sqlite3_file] object associated with a particular database 809** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER]. 810** 811** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]] 812** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer 813** to the [sqlite3_file] object associated with the journal file (either 814** the [rollback journal] or the [write-ahead log]) for a particular database 815** connection. See also [SQLITE_FCNTL_FILE_POINTER]. 816** 817** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 818** No longer in use. 819** 820** <li>[[SQLITE_FCNTL_SYNC]] 821** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 822** sent to the VFS immediately before the xSync method is invoked on a 823** database file descriptor. Or, if the xSync method is not invoked 824** because the user has configured SQLite with 825** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 826** of the xSync method. In most cases, the pointer argument passed with 827** this file-control is NULL. However, if the database file is being synced 828** as part of a multi-database commit, the argument points to a nul-terminated 829** string containing the transactions master-journal file name. VFSes that 830** do not need this signal should silently ignore this opcode. Applications 831** should not call [sqlite3_file_control()] with this opcode as doing so may 832** disrupt the operation of the specialized VFSes that do require it. 833** 834** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 835** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 836** and sent to the VFS after a transaction has been committed immediately 837** but before the database is unlocked. VFSes that do not need this signal 838** should silently ignore this opcode. Applications should not call 839** [sqlite3_file_control()] with this opcode as doing so may disrupt the 840** operation of the specialized VFSes that do require it. 841** 842** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 843** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 844** retry counts and intervals for certain disk I/O operations for the 845** windows [VFS] in order to provide robustness in the presence of 846** anti-virus programs. By default, the windows VFS will retry file read, 847** file write, and file delete operations up to 10 times, with a delay 848** of 25 milliseconds before the first retry and with the delay increasing 849** by an additional 25 milliseconds with each subsequent retry. This 850** opcode allows these two values (10 retries and 25 milliseconds of delay) 851** to be adjusted. The values are changed for all database connections 852** within the same process. The argument is a pointer to an array of two 853** integers where the first integer i the new retry count and the second 854** integer is the delay. If either integer is negative, then the setting 855** is not changed but instead the prior value of that setting is written 856** into the array entry, allowing the current retry settings to be 857** interrogated. The zDbName parameter is ignored. 858** 859** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 860** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 861** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 862** write ahead log and shared memory files used for transaction control 863** are automatically deleted when the latest connection to the database 864** closes. Setting persistent WAL mode causes those files to persist after 865** close. Persisting the files is useful when other processes that do not 866** have write permission on the directory containing the database file want 867** to read the database file, as the WAL and shared memory files must exist 868** in order for the database to be readable. The fourth parameter to 869** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 870** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 871** WAL mode. If the integer is -1, then it is overwritten with the current 872** WAL persistence setting. 873** 874** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 875** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 876** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 877** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 878** xDeviceCharacteristics methods. The fourth parameter to 879** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 880** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 881** mode. If the integer is -1, then it is overwritten with the current 882** zero-damage mode setting. 883** 884** <li>[[SQLITE_FCNTL_OVERWRITE]] 885** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 886** a write transaction to indicate that, unless it is rolled back for some 887** reason, the entire database file will be overwritten by the current 888** transaction. This is used by VACUUM operations. 889** 890** <li>[[SQLITE_FCNTL_VFSNAME]] 891** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 892** all [VFSes] in the VFS stack. The names are of all VFS shims and the 893** final bottom-level VFS are written into memory obtained from 894** [sqlite3_malloc()] and the result is stored in the char* variable 895** that the fourth parameter of [sqlite3_file_control()] points to. 896** The caller is responsible for freeing the memory when done. As with 897** all file-control actions, there is no guarantee that this will actually 898** do anything. Callers should initialize the char* variable to a NULL 899** pointer in case this file-control is not implemented. This file-control 900** is intended for diagnostic use only. 901** 902** <li>[[SQLITE_FCNTL_VFS_POINTER]] 903** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 904** [VFSes] currently in use. ^(The argument X in 905** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 906** of type "[sqlite3_vfs] **". This opcodes will set *X 907** to a pointer to the top-level VFS.)^ 908** ^When there are multiple VFS shims in the stack, this opcode finds the 909** upper-most shim only. 910** 911** <li>[[SQLITE_FCNTL_PRAGMA]] 912** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 913** file control is sent to the open [sqlite3_file] object corresponding 914** to the database file to which the pragma statement refers. ^The argument 915** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 916** pointers to strings (char**) in which the second element of the array 917** is the name of the pragma and the third element is the argument to the 918** pragma or NULL if the pragma has no argument. ^The handler for an 919** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 920** of the char** argument point to a string obtained from [sqlite3_mprintf()] 921** or the equivalent and that string will become the result of the pragma or 922** the error message if the pragma fails. ^If the 923** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 924** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 925** file control returns [SQLITE_OK], then the parser assumes that the 926** VFS has handled the PRAGMA itself and the parser generates a no-op 927** prepared statement if result string is NULL, or that returns a copy 928** of the result string if the string is non-NULL. 929** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 930** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 931** that the VFS encountered an error while handling the [PRAGMA] and the 932** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 933** file control occurs at the beginning of pragma statement analysis and so 934** it is able to override built-in [PRAGMA] statements. 935** 936** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 937** ^The [SQLITE_FCNTL_BUSYHANDLER] 938** file-control may be invoked by SQLite on the database file handle 939** shortly after it is opened in order to provide a custom VFS with access 940** to the connections busy-handler callback. The argument is of type (void **) 941** - an array of two (void *) values. The first (void *) actually points 942** to a function of type (int (*)(void *)). In order to invoke the connections 943** busy-handler, this function should be invoked with the second (void *) in 944** the array as the only argument. If it returns non-zero, then the operation 945** should be retried. If it returns zero, the custom VFS should abandon the 946** current operation. 947** 948** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 949** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 950** to have SQLite generate a 951** temporary filename using the same algorithm that is followed to generate 952** temporary filenames for TEMP tables and other internal uses. The 953** argument should be a char** which will be filled with the filename 954** written into memory obtained from [sqlite3_malloc()]. The caller should 955** invoke [sqlite3_free()] on the result to avoid a memory leak. 956** 957** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 958** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 959** maximum number of bytes that will be used for memory-mapped I/O. 960** The argument is a pointer to a value of type sqlite3_int64 that 961** is an advisory maximum number of bytes in the file to memory map. The 962** pointer is overwritten with the old value. The limit is not changed if 963** the value originally pointed to is negative, and so the current limit 964** can be queried by passing in a pointer to a negative number. This 965** file-control is used internally to implement [PRAGMA mmap_size]. 966** 967** <li>[[SQLITE_FCNTL_TRACE]] 968** The [SQLITE_FCNTL_TRACE] file control provides advisory information 969** to the VFS about what the higher layers of the SQLite stack are doing. 970** This file control is used by some VFS activity tracing [shims]. 971** The argument is a zero-terminated string. Higher layers in the 972** SQLite stack may generate instances of this file control if 973** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 974** 975** <li>[[SQLITE_FCNTL_HAS_MOVED]] 976** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 977** pointer to an integer and it writes a boolean into that integer depending 978** on whether or not the file has been renamed, moved, or deleted since it 979** was first opened. 980** 981** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]] 982** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the 983** underlying native file handle associated with a file handle. This file 984** control interprets its argument as a pointer to a native file handle and 985** writes the resulting value there. 986** 987** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 988** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 989** opcode causes the xFileControl method to swap the file handle with the one 990** pointed to by the pArg argument. This capability is used during testing 991** and only needs to be supported when SQLITE_TEST is defined. 992** 993** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 994** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 995** be advantageous to block on the next WAL lock if the lock is not immediately 996** available. The WAL subsystem issues this signal during rare 997** circumstances in order to fix a problem with priority inversion. 998** Applications should <em>not</em> use this file-control. 999** 1000** <li>[[SQLITE_FCNTL_ZIPVFS]] 1001** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 1002** VFS should return SQLITE_NOTFOUND for this opcode. 1003** 1004** <li>[[SQLITE_FCNTL_RBU]] 1005** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 1006** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 1007** this opcode. 1008** </ul> 1009*/ 1010#define SQLITE_FCNTL_LOCKSTATE 1 1011#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1012#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1013#define SQLITE_FCNTL_LAST_ERRNO 4 1014#define SQLITE_FCNTL_SIZE_HINT 5 1015#define SQLITE_FCNTL_CHUNK_SIZE 6 1016#define SQLITE_FCNTL_FILE_POINTER 7 1017#define SQLITE_FCNTL_SYNC_OMITTED 8 1018#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1019#define SQLITE_FCNTL_PERSIST_WAL 10 1020#define SQLITE_FCNTL_OVERWRITE 11 1021#define SQLITE_FCNTL_VFSNAME 12 1022#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1023#define SQLITE_FCNTL_PRAGMA 14 1024#define SQLITE_FCNTL_BUSYHANDLER 15 1025#define SQLITE_FCNTL_TEMPFILENAME 16 1026#define SQLITE_FCNTL_MMAP_SIZE 18 1027#define SQLITE_FCNTL_TRACE 19 1028#define SQLITE_FCNTL_HAS_MOVED 20 1029#define SQLITE_FCNTL_SYNC 21 1030#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1031#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1032#define SQLITE_FCNTL_WAL_BLOCK 24 1033#define SQLITE_FCNTL_ZIPVFS 25 1034#define SQLITE_FCNTL_RBU 26 1035#define SQLITE_FCNTL_VFS_POINTER 27 1036#define SQLITE_FCNTL_JOURNAL_POINTER 28 1037#define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1038#define SQLITE_FCNTL_PDB 30 1039 1040/* deprecated names */ 1041#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1042#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1043#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1044 1045 1046/* 1047** CAPI3REF: Mutex Handle 1048** 1049** The mutex module within SQLite defines [sqlite3_mutex] to be an 1050** abstract type for a mutex object. The SQLite core never looks 1051** at the internal representation of an [sqlite3_mutex]. It only 1052** deals with pointers to the [sqlite3_mutex] object. 1053** 1054** Mutexes are created using [sqlite3_mutex_alloc()]. 1055*/ 1056typedef struct sqlite3_mutex sqlite3_mutex; 1057 1058/* 1059** CAPI3REF: Loadable Extension Thunk 1060** 1061** A pointer to the opaque sqlite3_api_routines structure is passed as 1062** the third parameter to entry points of [loadable extensions]. This 1063** structure must be typedefed in order to work around compiler warnings 1064** on some platforms. 1065*/ 1066typedef struct sqlite3_api_routines sqlite3_api_routines; 1067 1068/* 1069** CAPI3REF: OS Interface Object 1070** 1071** An instance of the sqlite3_vfs object defines the interface between 1072** the SQLite core and the underlying operating system. The "vfs" 1073** in the name of the object stands for "virtual file system". See 1074** the [VFS | VFS documentation] for further information. 1075** 1076** The value of the iVersion field is initially 1 but may be larger in 1077** future versions of SQLite. Additional fields may be appended to this 1078** object when the iVersion value is increased. Note that the structure 1079** of the sqlite3_vfs object changes in the transaction between 1080** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 1081** modified. 1082** 1083** The szOsFile field is the size of the subclassed [sqlite3_file] 1084** structure used by this VFS. mxPathname is the maximum length of 1085** a pathname in this VFS. 1086** 1087** Registered sqlite3_vfs objects are kept on a linked list formed by 1088** the pNext pointer. The [sqlite3_vfs_register()] 1089** and [sqlite3_vfs_unregister()] interfaces manage this list 1090** in a thread-safe way. The [sqlite3_vfs_find()] interface 1091** searches the list. Neither the application code nor the VFS 1092** implementation should use the pNext pointer. 1093** 1094** The pNext field is the only field in the sqlite3_vfs 1095** structure that SQLite will ever modify. SQLite will only access 1096** or modify this field while holding a particular static mutex. 1097** The application should never modify anything within the sqlite3_vfs 1098** object once the object has been registered. 1099** 1100** The zName field holds the name of the VFS module. The name must 1101** be unique across all VFS modules. 1102** 1103** [[sqlite3_vfs.xOpen]] 1104** ^SQLite guarantees that the zFilename parameter to xOpen 1105** is either a NULL pointer or string obtained 1106** from xFullPathname() with an optional suffix added. 1107** ^If a suffix is added to the zFilename parameter, it will 1108** consist of a single "-" character followed by no more than 1109** 11 alphanumeric and/or "-" characters. 1110** ^SQLite further guarantees that 1111** the string will be valid and unchanged until xClose() is 1112** called. Because of the previous sentence, 1113** the [sqlite3_file] can safely store a pointer to the 1114** filename if it needs to remember the filename for some reason. 1115** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1116** must invent its own temporary name for the file. ^Whenever the 1117** xFilename parameter is NULL it will also be the case that the 1118** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1119** 1120** The flags argument to xOpen() includes all bits set in 1121** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1122** or [sqlite3_open16()] is used, then flags includes at least 1123** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1124** If xOpen() opens a file read-only then it sets *pOutFlags to 1125** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1126** 1127** ^(SQLite will also add one of the following flags to the xOpen() 1128** call, depending on the object being opened: 1129** 1130** <ul> 1131** <li> [SQLITE_OPEN_MAIN_DB] 1132** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1133** <li> [SQLITE_OPEN_TEMP_DB] 1134** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1135** <li> [SQLITE_OPEN_TRANSIENT_DB] 1136** <li> [SQLITE_OPEN_SUBJOURNAL] 1137** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1138** <li> [SQLITE_OPEN_WAL] 1139** </ul>)^ 1140** 1141** The file I/O implementation can use the object type flags to 1142** change the way it deals with files. For example, an application 1143** that does not care about crash recovery or rollback might make 1144** the open of a journal file a no-op. Writes to this journal would 1145** also be no-ops, and any attempt to read the journal would return 1146** SQLITE_IOERR. Or the implementation might recognize that a database 1147** file will be doing page-aligned sector reads and writes in a random 1148** order and set up its I/O subsystem accordingly. 1149** 1150** SQLite might also add one of the following flags to the xOpen method: 1151** 1152** <ul> 1153** <li> [SQLITE_OPEN_DELETEONCLOSE] 1154** <li> [SQLITE_OPEN_EXCLUSIVE] 1155** </ul> 1156** 1157** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1158** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1159** will be set for TEMP databases and their journals, transient 1160** databases, and subjournals. 1161** 1162** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1163** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1164** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1165** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1166** SQLITE_OPEN_CREATE, is used to indicate that file should always 1167** be created, and that it is an error if it already exists. 1168** It is <i>not</i> used to indicate the file should be opened 1169** for exclusive access. 1170** 1171** ^At least szOsFile bytes of memory are allocated by SQLite 1172** to hold the [sqlite3_file] structure passed as the third 1173** argument to xOpen. The xOpen method does not have to 1174** allocate the structure; it should just fill it in. Note that 1175** the xOpen method must set the sqlite3_file.pMethods to either 1176** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1177** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1178** element will be valid after xOpen returns regardless of the success 1179** or failure of the xOpen call. 1180** 1181** [[sqlite3_vfs.xAccess]] 1182** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1183** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1184** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1185** to test whether a file is at least readable. The file can be a 1186** directory. 1187** 1188** ^SQLite will always allocate at least mxPathname+1 bytes for the 1189** output buffer xFullPathname. The exact size of the output buffer 1190** is also passed as a parameter to both methods. If the output buffer 1191** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1192** handled as a fatal error by SQLite, vfs implementations should endeavor 1193** to prevent this by setting mxPathname to a sufficiently large value. 1194** 1195** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1196** interfaces are not strictly a part of the filesystem, but they are 1197** included in the VFS structure for completeness. 1198** The xRandomness() function attempts to return nBytes bytes 1199** of good-quality randomness into zOut. The return value is 1200** the actual number of bytes of randomness obtained. 1201** The xSleep() method causes the calling thread to sleep for at 1202** least the number of microseconds given. ^The xCurrentTime() 1203** method returns a Julian Day Number for the current date and time as 1204** a floating point value. 1205** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1206** Day Number multiplied by 86400000 (the number of milliseconds in 1207** a 24-hour day). 1208** ^SQLite will use the xCurrentTimeInt64() method to get the current 1209** date and time if that method is available (if iVersion is 2 or 1210** greater and the function pointer is not NULL) and will fall back 1211** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1212** 1213** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1214** are not used by the SQLite core. These optional interfaces are provided 1215** by some VFSes to facilitate testing of the VFS code. By overriding 1216** system calls with functions under its control, a test program can 1217** simulate faults and error conditions that would otherwise be difficult 1218** or impossible to induce. The set of system calls that can be overridden 1219** varies from one VFS to another, and from one version of the same VFS to the 1220** next. Applications that use these interfaces must be prepared for any 1221** or all of these interfaces to be NULL or for their behavior to change 1222** from one release to the next. Applications must not attempt to access 1223** any of these methods if the iVersion of the VFS is less than 3. 1224*/ 1225typedef struct sqlite3_vfs sqlite3_vfs; 1226typedef void (*sqlite3_syscall_ptr)(void); 1227struct sqlite3_vfs { 1228 int iVersion; /* Structure version number (currently 3) */ 1229 int szOsFile; /* Size of subclassed sqlite3_file */ 1230 int mxPathname; /* Maximum file pathname length */ 1231 sqlite3_vfs *pNext; /* Next registered VFS */ 1232 const char *zName; /* Name of this virtual file system */ 1233 void *pAppData; /* Pointer to application-specific data */ 1234 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1235 int flags, int *pOutFlags); 1236 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1237 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1238 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1239 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1240 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1241 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1242 void (*xDlClose)(sqlite3_vfs*, void*); 1243 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1244 int (*xSleep)(sqlite3_vfs*, int microseconds); 1245 int (*xCurrentTime)(sqlite3_vfs*, double*); 1246 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1247 /* 1248 ** The methods above are in version 1 of the sqlite_vfs object 1249 ** definition. Those that follow are added in version 2 or later 1250 */ 1251 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1252 /* 1253 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1254 ** Those below are for version 3 and greater. 1255 */ 1256 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1257 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1258 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1259 /* 1260 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1261 ** New fields may be appended in future versions. The iVersion 1262 ** value will increment whenever this happens. 1263 */ 1264}; 1265 1266/* 1267** CAPI3REF: Flags for the xAccess VFS method 1268** 1269** These integer constants can be used as the third parameter to 1270** the xAccess method of an [sqlite3_vfs] object. They determine 1271** what kind of permissions the xAccess method is looking for. 1272** With SQLITE_ACCESS_EXISTS, the xAccess method 1273** simply checks whether the file exists. 1274** With SQLITE_ACCESS_READWRITE, the xAccess method 1275** checks whether the named directory is both readable and writable 1276** (in other words, if files can be added, removed, and renamed within 1277** the directory). 1278** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1279** [temp_store_directory pragma], though this could change in a future 1280** release of SQLite. 1281** With SQLITE_ACCESS_READ, the xAccess method 1282** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1283** currently unused, though it might be used in a future release of 1284** SQLite. 1285*/ 1286#define SQLITE_ACCESS_EXISTS 0 1287#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1288#define SQLITE_ACCESS_READ 2 /* Unused */ 1289 1290/* 1291** CAPI3REF: Flags for the xShmLock VFS method 1292** 1293** These integer constants define the various locking operations 1294** allowed by the xShmLock method of [sqlite3_io_methods]. The 1295** following are the only legal combinations of flags to the 1296** xShmLock method: 1297** 1298** <ul> 1299** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1300** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1301** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1302** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1303** </ul> 1304** 1305** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1306** was given on the corresponding lock. 1307** 1308** The xShmLock method can transition between unlocked and SHARED or 1309** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1310** and EXCLUSIVE. 1311*/ 1312#define SQLITE_SHM_UNLOCK 1 1313#define SQLITE_SHM_LOCK 2 1314#define SQLITE_SHM_SHARED 4 1315#define SQLITE_SHM_EXCLUSIVE 8 1316 1317/* 1318** CAPI3REF: Maximum xShmLock index 1319** 1320** The xShmLock method on [sqlite3_io_methods] may use values 1321** between 0 and this upper bound as its "offset" argument. 1322** The SQLite core will never attempt to acquire or release a 1323** lock outside of this range 1324*/ 1325#define SQLITE_SHM_NLOCK 8 1326 1327 1328/* 1329** CAPI3REF: Initialize The SQLite Library 1330** 1331** ^The sqlite3_initialize() routine initializes the 1332** SQLite library. ^The sqlite3_shutdown() routine 1333** deallocates any resources that were allocated by sqlite3_initialize(). 1334** These routines are designed to aid in process initialization and 1335** shutdown on embedded systems. Workstation applications using 1336** SQLite normally do not need to invoke either of these routines. 1337** 1338** A call to sqlite3_initialize() is an "effective" call if it is 1339** the first time sqlite3_initialize() is invoked during the lifetime of 1340** the process, or if it is the first time sqlite3_initialize() is invoked 1341** following a call to sqlite3_shutdown(). ^(Only an effective call 1342** of sqlite3_initialize() does any initialization. All other calls 1343** are harmless no-ops.)^ 1344** 1345** A call to sqlite3_shutdown() is an "effective" call if it is the first 1346** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1347** an effective call to sqlite3_shutdown() does any deinitialization. 1348** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1349** 1350** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1351** is not. The sqlite3_shutdown() interface must only be called from a 1352** single thread. All open [database connections] must be closed and all 1353** other SQLite resources must be deallocated prior to invoking 1354** sqlite3_shutdown(). 1355** 1356** Among other things, ^sqlite3_initialize() will invoke 1357** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1358** will invoke sqlite3_os_end(). 1359** 1360** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1361** ^If for some reason, sqlite3_initialize() is unable to initialize 1362** the library (perhaps it is unable to allocate a needed resource such 1363** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1364** 1365** ^The sqlite3_initialize() routine is called internally by many other 1366** SQLite interfaces so that an application usually does not need to 1367** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1368** calls sqlite3_initialize() so the SQLite library will be automatically 1369** initialized when [sqlite3_open()] is called if it has not be initialized 1370** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1371** compile-time option, then the automatic calls to sqlite3_initialize() 1372** are omitted and the application must call sqlite3_initialize() directly 1373** prior to using any other SQLite interface. For maximum portability, 1374** it is recommended that applications always invoke sqlite3_initialize() 1375** directly prior to using any other SQLite interface. Future releases 1376** of SQLite may require this. In other words, the behavior exhibited 1377** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1378** default behavior in some future release of SQLite. 1379** 1380** The sqlite3_os_init() routine does operating-system specific 1381** initialization of the SQLite library. The sqlite3_os_end() 1382** routine undoes the effect of sqlite3_os_init(). Typical tasks 1383** performed by these routines include allocation or deallocation 1384** of static resources, initialization of global variables, 1385** setting up a default [sqlite3_vfs] module, or setting up 1386** a default configuration using [sqlite3_config()]. 1387** 1388** The application should never invoke either sqlite3_os_init() 1389** or sqlite3_os_end() directly. The application should only invoke 1390** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1391** interface is called automatically by sqlite3_initialize() and 1392** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1393** implementations for sqlite3_os_init() and sqlite3_os_end() 1394** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1395** When [custom builds | built for other platforms] 1396** (using the [SQLITE_OS_OTHER=1] compile-time 1397** option) the application must supply a suitable implementation for 1398** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1399** implementation of sqlite3_os_init() or sqlite3_os_end() 1400** must return [SQLITE_OK] on success and some other [error code] upon 1401** failure. 1402*/ 1403int sqlite3_initialize(void); 1404int sqlite3_shutdown(void); 1405int sqlite3_os_init(void); 1406int sqlite3_os_end(void); 1407 1408/* 1409** CAPI3REF: Configuring The SQLite Library 1410** 1411** The sqlite3_config() interface is used to make global configuration 1412** changes to SQLite in order to tune SQLite to the specific needs of 1413** the application. The default configuration is recommended for most 1414** applications and so this routine is usually not necessary. It is 1415** provided to support rare applications with unusual needs. 1416** 1417** <b>The sqlite3_config() interface is not threadsafe. The application 1418** must ensure that no other SQLite interfaces are invoked by other 1419** threads while sqlite3_config() is running.</b> 1420** 1421** The sqlite3_config() interface 1422** may only be invoked prior to library initialization using 1423** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1424** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1425** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1426** Note, however, that ^sqlite3_config() can be called as part of the 1427** implementation of an application-defined [sqlite3_os_init()]. 1428** 1429** The first argument to sqlite3_config() is an integer 1430** [configuration option] that determines 1431** what property of SQLite is to be configured. Subsequent arguments 1432** vary depending on the [configuration option] 1433** in the first argument. 1434** 1435** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1436** ^If the option is unknown or SQLite is unable to set the option 1437** then this routine returns a non-zero [error code]. 1438*/ 1439int sqlite3_config(int, ...); 1440 1441/* 1442** CAPI3REF: Configure database connections 1443** METHOD: sqlite3 1444** 1445** The sqlite3_db_config() interface is used to make configuration 1446** changes to a [database connection]. The interface is similar to 1447** [sqlite3_config()] except that the changes apply to a single 1448** [database connection] (specified in the first argument). 1449** 1450** The second argument to sqlite3_db_config(D,V,...) is the 1451** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1452** that indicates what aspect of the [database connection] is being configured. 1453** Subsequent arguments vary depending on the configuration verb. 1454** 1455** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1456** the call is considered successful. 1457*/ 1458int sqlite3_db_config(sqlite3*, int op, ...); 1459 1460/* 1461** CAPI3REF: Memory Allocation Routines 1462** 1463** An instance of this object defines the interface between SQLite 1464** and low-level memory allocation routines. 1465** 1466** This object is used in only one place in the SQLite interface. 1467** A pointer to an instance of this object is the argument to 1468** [sqlite3_config()] when the configuration option is 1469** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1470** By creating an instance of this object 1471** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1472** during configuration, an application can specify an alternative 1473** memory allocation subsystem for SQLite to use for all of its 1474** dynamic memory needs. 1475** 1476** Note that SQLite comes with several [built-in memory allocators] 1477** that are perfectly adequate for the overwhelming majority of applications 1478** and that this object is only useful to a tiny minority of applications 1479** with specialized memory allocation requirements. This object is 1480** also used during testing of SQLite in order to specify an alternative 1481** memory allocator that simulates memory out-of-memory conditions in 1482** order to verify that SQLite recovers gracefully from such 1483** conditions. 1484** 1485** The xMalloc, xRealloc, and xFree methods must work like the 1486** malloc(), realloc() and free() functions from the standard C library. 1487** ^SQLite guarantees that the second argument to 1488** xRealloc is always a value returned by a prior call to xRoundup. 1489** 1490** xSize should return the allocated size of a memory allocation 1491** previously obtained from xMalloc or xRealloc. The allocated size 1492** is always at least as big as the requested size but may be larger. 1493** 1494** The xRoundup method returns what would be the allocated size of 1495** a memory allocation given a particular requested size. Most memory 1496** allocators round up memory allocations at least to the next multiple 1497** of 8. Some allocators round up to a larger multiple or to a power of 2. 1498** Every memory allocation request coming in through [sqlite3_malloc()] 1499** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1500** that causes the corresponding memory allocation to fail. 1501** 1502** The xInit method initializes the memory allocator. For example, 1503** it might allocate any require mutexes or initialize internal data 1504** structures. The xShutdown method is invoked (indirectly) by 1505** [sqlite3_shutdown()] and should deallocate any resources acquired 1506** by xInit. The pAppData pointer is used as the only parameter to 1507** xInit and xShutdown. 1508** 1509** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1510** the xInit method, so the xInit method need not be threadsafe. The 1511** xShutdown method is only called from [sqlite3_shutdown()] so it does 1512** not need to be threadsafe either. For all other methods, SQLite 1513** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1514** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1515** it is by default) and so the methods are automatically serialized. 1516** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1517** methods must be threadsafe or else make their own arrangements for 1518** serialization. 1519** 1520** SQLite will never invoke xInit() more than once without an intervening 1521** call to xShutdown(). 1522*/ 1523typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1524struct sqlite3_mem_methods { 1525 void *(*xMalloc)(int); /* Memory allocation function */ 1526 void (*xFree)(void*); /* Free a prior allocation */ 1527 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1528 int (*xSize)(void*); /* Return the size of an allocation */ 1529 int (*xRoundup)(int); /* Round up request size to allocation size */ 1530 int (*xInit)(void*); /* Initialize the memory allocator */ 1531 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1532 void *pAppData; /* Argument to xInit() and xShutdown() */ 1533}; 1534 1535/* 1536** CAPI3REF: Configuration Options 1537** KEYWORDS: {configuration option} 1538** 1539** These constants are the available integer configuration options that 1540** can be passed as the first argument to the [sqlite3_config()] interface. 1541** 1542** New configuration options may be added in future releases of SQLite. 1543** Existing configuration options might be discontinued. Applications 1544** should check the return code from [sqlite3_config()] to make sure that 1545** the call worked. The [sqlite3_config()] interface will return a 1546** non-zero [error code] if a discontinued or unsupported configuration option 1547** is invoked. 1548** 1549** <dl> 1550** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1551** <dd>There are no arguments to this option. ^This option sets the 1552** [threading mode] to Single-thread. In other words, it disables 1553** all mutexing and puts SQLite into a mode where it can only be used 1554** by a single thread. ^If SQLite is compiled with 1555** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1556** it is not possible to change the [threading mode] from its default 1557** value of Single-thread and so [sqlite3_config()] will return 1558** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1559** configuration option.</dd> 1560** 1561** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1562** <dd>There are no arguments to this option. ^This option sets the 1563** [threading mode] to Multi-thread. In other words, it disables 1564** mutexing on [database connection] and [prepared statement] objects. 1565** The application is responsible for serializing access to 1566** [database connections] and [prepared statements]. But other mutexes 1567** are enabled so that SQLite will be safe to use in a multi-threaded 1568** environment as long as no two threads attempt to use the same 1569** [database connection] at the same time. ^If SQLite is compiled with 1570** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1571** it is not possible to set the Multi-thread [threading mode] and 1572** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1573** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1574** 1575** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1576** <dd>There are no arguments to this option. ^This option sets the 1577** [threading mode] to Serialized. In other words, this option enables 1578** all mutexes including the recursive 1579** mutexes on [database connection] and [prepared statement] objects. 1580** In this mode (which is the default when SQLite is compiled with 1581** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1582** to [database connections] and [prepared statements] so that the 1583** application is free to use the same [database connection] or the 1584** same [prepared statement] in different threads at the same time. 1585** ^If SQLite is compiled with 1586** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1587** it is not possible to set the Serialized [threading mode] and 1588** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1589** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1590** 1591** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1592** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1593** a pointer to an instance of the [sqlite3_mem_methods] structure. 1594** The argument specifies 1595** alternative low-level memory allocation routines to be used in place of 1596** the memory allocation routines built into SQLite.)^ ^SQLite makes 1597** its own private copy of the content of the [sqlite3_mem_methods] structure 1598** before the [sqlite3_config()] call returns.</dd> 1599** 1600** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1601** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1602** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1603** The [sqlite3_mem_methods] 1604** structure is filled with the currently defined memory allocation routines.)^ 1605** This option can be used to overload the default memory allocation 1606** routines with a wrapper that simulations memory allocation failure or 1607** tracks memory usage, for example. </dd> 1608** 1609** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1610** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1611** interpreted as a boolean, which enables or disables the collection of 1612** memory allocation statistics. ^(When memory allocation statistics are 1613** disabled, the following SQLite interfaces become non-operational: 1614** <ul> 1615** <li> [sqlite3_memory_used()] 1616** <li> [sqlite3_memory_highwater()] 1617** <li> [sqlite3_soft_heap_limit64()] 1618** <li> [sqlite3_status64()] 1619** </ul>)^ 1620** ^Memory allocation statistics are enabled by default unless SQLite is 1621** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1622** allocation statistics are disabled by default. 1623** </dd> 1624** 1625** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1626** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer 1627** that SQLite can use for scratch memory. ^(There are three arguments 1628** to SQLITE_CONFIG_SCRATCH: A pointer an 8-byte 1629** aligned memory buffer from which the scratch allocations will be 1630** drawn, the size of each scratch allocation (sz), 1631** and the maximum number of scratch allocations (N).)^ 1632** The first argument must be a pointer to an 8-byte aligned buffer 1633** of at least sz*N bytes of memory. 1634** ^SQLite will not use more than one scratch buffers per thread. 1635** ^SQLite will never request a scratch buffer that is more than 6 1636** times the database page size. 1637** ^If SQLite needs needs additional 1638** scratch memory beyond what is provided by this configuration option, then 1639** [sqlite3_malloc()] will be used to obtain the memory needed.<p> 1640** ^When the application provides any amount of scratch memory using 1641** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large 1642** [sqlite3_malloc|heap allocations]. 1643** This can help [Robson proof|prevent memory allocation failures] due to heap 1644** fragmentation in low-memory embedded systems. 1645** </dd> 1646** 1647** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1648** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1649** that SQLite can use for the database page cache with the default page 1650** cache implementation. 1651** This configuration option is a no-op if an application-define page 1652** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1653** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1654** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1655** and the number of cache lines (N). 1656** The sz argument should be the size of the largest database page 1657** (a power of two between 512 and 65536) plus some extra bytes for each 1658** page header. ^The number of extra bytes needed by the page header 1659** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1660** ^It is harmless, apart from the wasted memory, 1661** for the sz parameter to be larger than necessary. The pMem 1662** argument must be either a NULL pointer or a pointer to an 8-byte 1663** aligned block of memory of at least sz*N bytes, otherwise 1664** subsequent behavior is undefined. 1665** ^When pMem is not NULL, SQLite will strive to use the memory provided 1666** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1667** a page cache line is larger than sz bytes or if all of the pMem buffer 1668** is exhausted. 1669** ^If pMem is NULL and N is non-zero, then each database connection 1670** does an initial bulk allocation for page cache memory 1671** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1672** of -1024*N bytes if N is negative, . ^If additional 1673** page cache memory is needed beyond what is provided by the initial 1674** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1675** additional cache line. </dd> 1676** 1677** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1678** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1679** that SQLite will use for all of its dynamic memory allocation needs 1680** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and 1681** [SQLITE_CONFIG_PAGECACHE]. 1682** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1683** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1684** [SQLITE_ERROR] if invoked otherwise. 1685** ^There are three arguments to SQLITE_CONFIG_HEAP: 1686** An 8-byte aligned pointer to the memory, 1687** the number of bytes in the memory buffer, and the minimum allocation size. 1688** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1689** to using its default memory allocator (the system malloc() implementation), 1690** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1691** memory pointer is not NULL then the alternative memory 1692** allocator is engaged to handle all of SQLites memory allocation needs. 1693** The first pointer (the memory pointer) must be aligned to an 8-byte 1694** boundary or subsequent behavior of SQLite will be undefined. 1695** The minimum allocation size is capped at 2**12. Reasonable values 1696** for the minimum allocation size are 2**5 through 2**8.</dd> 1697** 1698** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1699** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1700** pointer to an instance of the [sqlite3_mutex_methods] structure. 1701** The argument specifies alternative low-level mutex routines to be used 1702** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1703** the content of the [sqlite3_mutex_methods] structure before the call to 1704** [sqlite3_config()] returns. ^If SQLite is compiled with 1705** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1706** the entire mutexing subsystem is omitted from the build and hence calls to 1707** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1708** return [SQLITE_ERROR].</dd> 1709** 1710** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1711** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1712** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1713** [sqlite3_mutex_methods] 1714** structure is filled with the currently defined mutex routines.)^ 1715** This option can be used to overload the default mutex allocation 1716** routines with a wrapper used to track mutex usage for performance 1717** profiling or testing, for example. ^If SQLite is compiled with 1718** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1719** the entire mutexing subsystem is omitted from the build and hence calls to 1720** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1721** return [SQLITE_ERROR].</dd> 1722** 1723** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1724** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1725** the default size of lookaside memory on each [database connection]. 1726** The first argument is the 1727** size of each lookaside buffer slot and the second is the number of 1728** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1729** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1730** option to [sqlite3_db_config()] can be used to change the lookaside 1731** configuration on individual connections.)^ </dd> 1732** 1733** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1734** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1735** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1736** the interface to a custom page cache implementation.)^ 1737** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1738** 1739** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1740** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1741** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1742** the current page cache implementation into that object.)^ </dd> 1743** 1744** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1745** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1746** global [error log]. 1747** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1748** function with a call signature of void(*)(void*,int,const char*), 1749** and a pointer to void. ^If the function pointer is not NULL, it is 1750** invoked by [sqlite3_log()] to process each logging event. ^If the 1751** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1752** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1753** passed through as the first parameter to the application-defined logger 1754** function whenever that function is invoked. ^The second parameter to 1755** the logger function is a copy of the first parameter to the corresponding 1756** [sqlite3_log()] call and is intended to be a [result code] or an 1757** [extended result code]. ^The third parameter passed to the logger is 1758** log message after formatting via [sqlite3_snprintf()]. 1759** The SQLite logging interface is not reentrant; the logger function 1760** supplied by the application must not invoke any SQLite interface. 1761** In a multi-threaded application, the application-defined logger 1762** function must be threadsafe. </dd> 1763** 1764** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1765** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1766** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1767** then URI handling is globally disabled.)^ ^If URI handling is globally 1768** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1769** [sqlite3_open16()] or 1770** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1771** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1772** connection is opened. ^If it is globally disabled, filenames are 1773** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1774** database connection is opened. ^(By default, URI handling is globally 1775** disabled. The default value may be changed by compiling with the 1776** [SQLITE_USE_URI] symbol defined.)^ 1777** 1778** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1779** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1780** argument which is interpreted as a boolean in order to enable or disable 1781** the use of covering indices for full table scans in the query optimizer. 1782** ^The default setting is determined 1783** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1784** if that compile-time option is omitted. 1785** The ability to disable the use of covering indices for full table scans 1786** is because some incorrectly coded legacy applications might malfunction 1787** when the optimization is enabled. Providing the ability to 1788** disable the optimization allows the older, buggy application code to work 1789** without change even with newer versions of SQLite. 1790** 1791** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1792** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1793** <dd> These options are obsolete and should not be used by new code. 1794** They are retained for backwards compatibility but are now no-ops. 1795** </dd> 1796** 1797** [[SQLITE_CONFIG_SQLLOG]] 1798** <dt>SQLITE_CONFIG_SQLLOG 1799** <dd>This option is only available if sqlite is compiled with the 1800** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1801** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1802** The second should be of type (void*). The callback is invoked by the library 1803** in three separate circumstances, identified by the value passed as the 1804** fourth parameter. If the fourth parameter is 0, then the database connection 1805** passed as the second argument has just been opened. The third argument 1806** points to a buffer containing the name of the main database file. If the 1807** fourth parameter is 1, then the SQL statement that the third parameter 1808** points to has just been executed. Or, if the fourth parameter is 2, then 1809** the connection being passed as the second parameter is being closed. The 1810** third parameter is passed NULL In this case. An example of using this 1811** configuration option can be seen in the "test_sqllog.c" source file in 1812** the canonical SQLite source tree.</dd> 1813** 1814** [[SQLITE_CONFIG_MMAP_SIZE]] 1815** <dt>SQLITE_CONFIG_MMAP_SIZE 1816** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1817** that are the default mmap size limit (the default setting for 1818** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1819** ^The default setting can be overridden by each database connection using 1820** either the [PRAGMA mmap_size] command, or by using the 1821** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1822** will be silently truncated if necessary so that it does not exceed the 1823** compile-time maximum mmap size set by the 1824** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1825** ^If either argument to this option is negative, then that argument is 1826** changed to its compile-time default. 1827** 1828** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1829** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1830** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1831** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1832** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1833** that specifies the maximum size of the created heap. 1834** 1835** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1836** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1837** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1838** is a pointer to an integer and writes into that integer the number of extra 1839** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1840** The amount of extra space required can change depending on the compiler, 1841** target platform, and SQLite version. 1842** 1843** [[SQLITE_CONFIG_PMASZ]] 1844** <dt>SQLITE_CONFIG_PMASZ 1845** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1846** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1847** sorter to that integer. The default minimum PMA Size is set by the 1848** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1849** to help with sort operations when multithreaded sorting 1850** is enabled (using the [PRAGMA threads] command) and the amount of content 1851** to be sorted exceeds the page size times the minimum of the 1852** [PRAGMA cache_size] setting and this value. 1853** 1854** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 1855** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 1856** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 1857** becomes the [statement journal] spill-to-disk threshold. 1858** [Statement journals] are held in memory until their size (in bytes) 1859** exceeds this threshold, at which point they are written to disk. 1860** Or if the threshold is -1, statement journals are always held 1861** exclusively in memory. 1862** Since many statement journals never become large, setting the spill 1863** threshold to a value such as 64KiB can greatly reduce the amount of 1864** I/O required to support statement rollback. 1865** The default value for this setting is controlled by the 1866** [SQLITE_STMTJRNL_SPILL] compile-time option. 1867** </dl> 1868*/ 1869#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1870#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1871#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1872#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1873#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1874#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1875#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1876#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1877#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1878#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1879#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1880/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1881#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1882#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1883#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1884#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1885#define SQLITE_CONFIG_URI 17 /* int */ 1886#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1887#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1888#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1889#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1890#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1891#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1892#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1893#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 1894#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 1895 1896/* 1897** CAPI3REF: Database Connection Configuration Options 1898** 1899** These constants are the available integer configuration options that 1900** can be passed as the second argument to the [sqlite3_db_config()] interface. 1901** 1902** New configuration options may be added in future releases of SQLite. 1903** Existing configuration options might be discontinued. Applications 1904** should check the return code from [sqlite3_db_config()] to make sure that 1905** the call worked. ^The [sqlite3_db_config()] interface will return a 1906** non-zero [error code] if a discontinued or unsupported configuration option 1907** is invoked. 1908** 1909** <dl> 1910** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1911** <dd> ^This option takes three additional arguments that determine the 1912** [lookaside memory allocator] configuration for the [database connection]. 1913** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1914** pointer to a memory buffer to use for lookaside memory. 1915** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1916** may be NULL in which case SQLite will allocate the 1917** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1918** size of each lookaside buffer slot. ^The third argument is the number of 1919** slots. The size of the buffer in the first argument must be greater than 1920** or equal to the product of the second and third arguments. The buffer 1921** must be aligned to an 8-byte boundary. ^If the second argument to 1922** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1923** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1924** configuration for a database connection can only be changed when that 1925** connection is not currently using lookaside memory, or in other words 1926** when the "current value" returned by 1927** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1928** Any attempt to change the lookaside memory configuration when lookaside 1929** memory is in use leaves the configuration unchanged and returns 1930** [SQLITE_BUSY].)^</dd> 1931** 1932** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1933** <dd> ^This option is used to enable or disable the enforcement of 1934** [foreign key constraints]. There should be two additional arguments. 1935** The first argument is an integer which is 0 to disable FK enforcement, 1936** positive to enable FK enforcement or negative to leave FK enforcement 1937** unchanged. The second parameter is a pointer to an integer into which 1938** is written 0 or 1 to indicate whether FK enforcement is off or on 1939** following this call. The second parameter may be a NULL pointer, in 1940** which case the FK enforcement setting is not reported back. </dd> 1941** 1942** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1943** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1944** There should be two additional arguments. 1945** The first argument is an integer which is 0 to disable triggers, 1946** positive to enable triggers or negative to leave the setting unchanged. 1947** The second parameter is a pointer to an integer into which 1948** is written 0 or 1 to indicate whether triggers are disabled or enabled 1949** following this call. The second parameter may be a NULL pointer, in 1950** which case the trigger setting is not reported back. </dd> 1951** 1952** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 1953** <dd> ^This option is used to enable or disable the two-argument 1954** version of the [fts3_tokenizer()] function which is part of the 1955** [FTS3] full-text search engine extension. 1956** There should be two additional arguments. 1957** The first argument is an integer which is 0 to disable fts3_tokenizer() or 1958** positive to enable fts3_tokenizer() or negative to leave the setting 1959** unchanged. 1960** The second parameter is a pointer to an integer into which 1961** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 1962** following this call. The second parameter may be a NULL pointer, in 1963** which case the new setting is not reported back. </dd> 1964** 1965** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 1966** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 1967** interface independently of the [load_extension()] SQL function. 1968** The [sqlite3_enable_load_extension()] API enables or disables both the 1969** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 1970** There should be two additional arguments. 1971** When the first argument to this interface is 1, then only the C-API is 1972** enabled and the SQL function remains disabled. If the first argument to 1973** this interface is 0, then both the C-API and the SQL function are disabled. 1974** If the first argument is -1, then no changes are made to state of either the 1975** C-API or the SQL function. 1976** The second parameter is a pointer to an integer into which 1977** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 1978** is disabled or enabled following this call. The second parameter may 1979** be a NULL pointer, in which case the new setting is not reported back. 1980** </dd> 1981** 1982** <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 1983** <dd> ^This option is used to change the name of the "main" database 1984** schema. ^The sole argument is a pointer to a constant UTF8 string 1985** which will become the new schema name in place of "main". ^SQLite 1986** does not make a copy of the new main schema name string, so the application 1987** must ensure that the argument passed into this DBCONFIG option is unchanged 1988** until after the database connection closes. 1989** </dd> 1990** 1991** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 1992** <dd> Usually, when a database in wal mode is closed or detached from a 1993** database handle, SQLite checks if this will mean that there are now no 1994** connections at all to the database. If so, it performs a checkpoint 1995** operation before closing the connection. This option may be used to 1996** override this behaviour. The first parameter passed to this operation 1997** is an integer - non-zero to disable checkpoints-on-close, or zero (the 1998** default) to enable them. The second parameter is a pointer to an integer 1999** into which is written 0 or 1 to indicate whether checkpoints-on-close 2000** have been disabled - 0 if they are not disabled, 1 if they are. 2001** </dd> 2002** 2003** </dl> 2004*/ 2005#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2006#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2007#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2008#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2009#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2010#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2011#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2012 2013 2014/* 2015** CAPI3REF: Enable Or Disable Extended Result Codes 2016** METHOD: sqlite3 2017** 2018** ^The sqlite3_extended_result_codes() routine enables or disables the 2019** [extended result codes] feature of SQLite. ^The extended result 2020** codes are disabled by default for historical compatibility. 2021*/ 2022int sqlite3_extended_result_codes(sqlite3*, int onoff); 2023 2024/* 2025** CAPI3REF: Last Insert Rowid 2026** METHOD: sqlite3 2027** 2028** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2029** has a unique 64-bit signed 2030** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2031** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2032** names are not also used by explicitly declared columns. ^If 2033** the table has a column of type [INTEGER PRIMARY KEY] then that column 2034** is another alias for the rowid. 2035** 2036** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the 2037** most recent successful [INSERT] into a rowid table or [virtual table] 2038** on database connection D. 2039** ^Inserts into [WITHOUT ROWID] tables are not recorded. 2040** ^If no successful [INSERT]s into rowid tables 2041** have ever occurred on the database connection D, 2042** then sqlite3_last_insert_rowid(D) returns zero. 2043** 2044** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 2045** method, then this routine will return the [rowid] of the inserted 2046** row as long as the trigger or virtual table method is running. 2047** But once the trigger or virtual table method ends, the value returned 2048** by this routine reverts to what it was before the trigger or virtual 2049** table method began.)^ 2050** 2051** ^An [INSERT] that fails due to a constraint violation is not a 2052** successful [INSERT] and does not change the value returned by this 2053** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2054** and INSERT OR ABORT make no changes to the return value of this 2055** routine when their insertion fails. ^(When INSERT OR REPLACE 2056** encounters a constraint violation, it does not fail. The 2057** INSERT continues to completion after deleting rows that caused 2058** the constraint problem so INSERT OR REPLACE will always change 2059** the return value of this interface.)^ 2060** 2061** ^For the purposes of this routine, an [INSERT] is considered to 2062** be successful even if it is subsequently rolled back. 2063** 2064** This function is accessible to SQL statements via the 2065** [last_insert_rowid() SQL function]. 2066** 2067** If a separate thread performs a new [INSERT] on the same 2068** database connection while the [sqlite3_last_insert_rowid()] 2069** function is running and thus changes the last insert [rowid], 2070** then the value returned by [sqlite3_last_insert_rowid()] is 2071** unpredictable and might not equal either the old or the new 2072** last insert [rowid]. 2073*/ 2074sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2075 2076/* 2077** CAPI3REF: Count The Number Of Rows Modified 2078** METHOD: sqlite3 2079** 2080** ^This function returns the number of rows modified, inserted or 2081** deleted by the most recently completed INSERT, UPDATE or DELETE 2082** statement on the database connection specified by the only parameter. 2083** ^Executing any other type of SQL statement does not modify the value 2084** returned by this function. 2085** 2086** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2087** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2088** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2089** 2090** Changes to a view that are intercepted by 2091** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2092** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2093** DELETE statement run on a view is always zero. Only changes made to real 2094** tables are counted. 2095** 2096** Things are more complicated if the sqlite3_changes() function is 2097** executed while a trigger program is running. This may happen if the 2098** program uses the [changes() SQL function], or if some other callback 2099** function invokes sqlite3_changes() directly. Essentially: 2100** 2101** <ul> 2102** <li> ^(Before entering a trigger program the value returned by 2103** sqlite3_changes() function is saved. After the trigger program 2104** has finished, the original value is restored.)^ 2105** 2106** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2107** statement sets the value returned by sqlite3_changes() 2108** upon completion as normal. Of course, this value will not include 2109** any changes performed by sub-triggers, as the sqlite3_changes() 2110** value will be saved and restored after each sub-trigger has run.)^ 2111** </ul> 2112** 2113** ^This means that if the changes() SQL function (or similar) is used 2114** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2115** returns the value as set when the calling statement began executing. 2116** ^If it is used by the second or subsequent such statement within a trigger 2117** program, the value returned reflects the number of rows modified by the 2118** previous INSERT, UPDATE or DELETE statement within the same trigger. 2119** 2120** See also the [sqlite3_total_changes()] interface, the 2121** [count_changes pragma], and the [changes() SQL function]. 2122** 2123** If a separate thread makes changes on the same database connection 2124** while [sqlite3_changes()] is running then the value returned 2125** is unpredictable and not meaningful. 2126*/ 2127int sqlite3_changes(sqlite3*); 2128 2129/* 2130** CAPI3REF: Total Number Of Rows Modified 2131** METHOD: sqlite3 2132** 2133** ^This function returns the total number of rows inserted, modified or 2134** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2135** since the database connection was opened, including those executed as 2136** part of trigger programs. ^Executing any other type of SQL statement 2137** does not affect the value returned by sqlite3_total_changes(). 2138** 2139** ^Changes made as part of [foreign key actions] are included in the 2140** count, but those made as part of REPLACE constraint resolution are 2141** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2142** are not counted. 2143** 2144** See also the [sqlite3_changes()] interface, the 2145** [count_changes pragma], and the [total_changes() SQL function]. 2146** 2147** If a separate thread makes changes on the same database connection 2148** while [sqlite3_total_changes()] is running then the value 2149** returned is unpredictable and not meaningful. 2150*/ 2151int sqlite3_total_changes(sqlite3*); 2152 2153/* 2154** CAPI3REF: Interrupt A Long-Running Query 2155** METHOD: sqlite3 2156** 2157** ^This function causes any pending database operation to abort and 2158** return at its earliest opportunity. This routine is typically 2159** called in response to a user action such as pressing "Cancel" 2160** or Ctrl-C where the user wants a long query operation to halt 2161** immediately. 2162** 2163** ^It is safe to call this routine from a thread different from the 2164** thread that is currently running the database operation. But it 2165** is not safe to call this routine with a [database connection] that 2166** is closed or might close before sqlite3_interrupt() returns. 2167** 2168** ^If an SQL operation is very nearly finished at the time when 2169** sqlite3_interrupt() is called, then it might not have an opportunity 2170** to be interrupted and might continue to completion. 2171** 2172** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2173** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2174** that is inside an explicit transaction, then the entire transaction 2175** will be rolled back automatically. 2176** 2177** ^The sqlite3_interrupt(D) call is in effect until all currently running 2178** SQL statements on [database connection] D complete. ^Any new SQL statements 2179** that are started after the sqlite3_interrupt() call and before the 2180** running statements reaches zero are interrupted as if they had been 2181** running prior to the sqlite3_interrupt() call. ^New SQL statements 2182** that are started after the running statement count reaches zero are 2183** not effected by the sqlite3_interrupt(). 2184** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2185** SQL statements is a no-op and has no effect on SQL statements 2186** that are started after the sqlite3_interrupt() call returns. 2187** 2188** If the database connection closes while [sqlite3_interrupt()] 2189** is running then bad things will likely happen. 2190*/ 2191void sqlite3_interrupt(sqlite3*); 2192 2193/* 2194** CAPI3REF: Determine If An SQL Statement Is Complete 2195** 2196** These routines are useful during command-line input to determine if the 2197** currently entered text seems to form a complete SQL statement or 2198** if additional input is needed before sending the text into 2199** SQLite for parsing. ^These routines return 1 if the input string 2200** appears to be a complete SQL statement. ^A statement is judged to be 2201** complete if it ends with a semicolon token and is not a prefix of a 2202** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2203** string literals or quoted identifier names or comments are not 2204** independent tokens (they are part of the token in which they are 2205** embedded) and thus do not count as a statement terminator. ^Whitespace 2206** and comments that follow the final semicolon are ignored. 2207** 2208** ^These routines return 0 if the statement is incomplete. ^If a 2209** memory allocation fails, then SQLITE_NOMEM is returned. 2210** 2211** ^These routines do not parse the SQL statements thus 2212** will not detect syntactically incorrect SQL. 2213** 2214** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2215** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2216** automatically by sqlite3_complete16(). If that initialization fails, 2217** then the return value from sqlite3_complete16() will be non-zero 2218** regardless of whether or not the input SQL is complete.)^ 2219** 2220** The input to [sqlite3_complete()] must be a zero-terminated 2221** UTF-8 string. 2222** 2223** The input to [sqlite3_complete16()] must be a zero-terminated 2224** UTF-16 string in native byte order. 2225*/ 2226int sqlite3_complete(const char *sql); 2227int sqlite3_complete16(const void *sql); 2228 2229/* 2230** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2231** KEYWORDS: {busy-handler callback} {busy handler} 2232** METHOD: sqlite3 2233** 2234** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2235** that might be invoked with argument P whenever 2236** an attempt is made to access a database table associated with 2237** [database connection] D when another thread 2238** or process has the table locked. 2239** The sqlite3_busy_handler() interface is used to implement 2240** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2241** 2242** ^If the busy callback is NULL, then [SQLITE_BUSY] 2243** is returned immediately upon encountering the lock. ^If the busy callback 2244** is not NULL, then the callback might be invoked with two arguments. 2245** 2246** ^The first argument to the busy handler is a copy of the void* pointer which 2247** is the third argument to sqlite3_busy_handler(). ^The second argument to 2248** the busy handler callback is the number of times that the busy handler has 2249** been invoked previously for the same locking event. ^If the 2250** busy callback returns 0, then no additional attempts are made to 2251** access the database and [SQLITE_BUSY] is returned 2252** to the application. 2253** ^If the callback returns non-zero, then another attempt 2254** is made to access the database and the cycle repeats. 2255** 2256** The presence of a busy handler does not guarantee that it will be invoked 2257** when there is lock contention. ^If SQLite determines that invoking the busy 2258** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2259** to the application instead of invoking the 2260** busy handler. 2261** Consider a scenario where one process is holding a read lock that 2262** it is trying to promote to a reserved lock and 2263** a second process is holding a reserved lock that it is trying 2264** to promote to an exclusive lock. The first process cannot proceed 2265** because it is blocked by the second and the second process cannot 2266** proceed because it is blocked by the first. If both processes 2267** invoke the busy handlers, neither will make any progress. Therefore, 2268** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2269** will induce the first process to release its read lock and allow 2270** the second process to proceed. 2271** 2272** ^The default busy callback is NULL. 2273** 2274** ^(There can only be a single busy handler defined for each 2275** [database connection]. Setting a new busy handler clears any 2276** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2277** or evaluating [PRAGMA busy_timeout=N] will change the 2278** busy handler and thus clear any previously set busy handler. 2279** 2280** The busy callback should not take any actions which modify the 2281** database connection that invoked the busy handler. In other words, 2282** the busy handler is not reentrant. Any such actions 2283** result in undefined behavior. 2284** 2285** A busy handler must not close the database connection 2286** or [prepared statement] that invoked the busy handler. 2287*/ 2288int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2289 2290/* 2291** CAPI3REF: Set A Busy Timeout 2292** METHOD: sqlite3 2293** 2294** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2295** for a specified amount of time when a table is locked. ^The handler 2296** will sleep multiple times until at least "ms" milliseconds of sleeping 2297** have accumulated. ^After at least "ms" milliseconds of sleeping, 2298** the handler returns 0 which causes [sqlite3_step()] to return 2299** [SQLITE_BUSY]. 2300** 2301** ^Calling this routine with an argument less than or equal to zero 2302** turns off all busy handlers. 2303** 2304** ^(There can only be a single busy handler for a particular 2305** [database connection] at any given moment. If another busy handler 2306** was defined (using [sqlite3_busy_handler()]) prior to calling 2307** this routine, that other busy handler is cleared.)^ 2308** 2309** See also: [PRAGMA busy_timeout] 2310*/ 2311int sqlite3_busy_timeout(sqlite3*, int ms); 2312 2313/* 2314** CAPI3REF: Convenience Routines For Running Queries 2315** METHOD: sqlite3 2316** 2317** This is a legacy interface that is preserved for backwards compatibility. 2318** Use of this interface is not recommended. 2319** 2320** Definition: A <b>result table</b> is memory data structure created by the 2321** [sqlite3_get_table()] interface. A result table records the 2322** complete query results from one or more queries. 2323** 2324** The table conceptually has a number of rows and columns. But 2325** these numbers are not part of the result table itself. These 2326** numbers are obtained separately. Let N be the number of rows 2327** and M be the number of columns. 2328** 2329** A result table is an array of pointers to zero-terminated UTF-8 strings. 2330** There are (N+1)*M elements in the array. The first M pointers point 2331** to zero-terminated strings that contain the names of the columns. 2332** The remaining entries all point to query results. NULL values result 2333** in NULL pointers. All other values are in their UTF-8 zero-terminated 2334** string representation as returned by [sqlite3_column_text()]. 2335** 2336** A result table might consist of one or more memory allocations. 2337** It is not safe to pass a result table directly to [sqlite3_free()]. 2338** A result table should be deallocated using [sqlite3_free_table()]. 2339** 2340** ^(As an example of the result table format, suppose a query result 2341** is as follows: 2342** 2343** <blockquote><pre> 2344** Name | Age 2345** ----------------------- 2346** Alice | 43 2347** Bob | 28 2348** Cindy | 21 2349** </pre></blockquote> 2350** 2351** There are two column (M==2) and three rows (N==3). Thus the 2352** result table has 8 entries. Suppose the result table is stored 2353** in an array names azResult. Then azResult holds this content: 2354** 2355** <blockquote><pre> 2356** azResult[0] = "Name"; 2357** azResult[1] = "Age"; 2358** azResult[2] = "Alice"; 2359** azResult[3] = "43"; 2360** azResult[4] = "Bob"; 2361** azResult[5] = "28"; 2362** azResult[6] = "Cindy"; 2363** azResult[7] = "21"; 2364** </pre></blockquote>)^ 2365** 2366** ^The sqlite3_get_table() function evaluates one or more 2367** semicolon-separated SQL statements in the zero-terminated UTF-8 2368** string of its 2nd parameter and returns a result table to the 2369** pointer given in its 3rd parameter. 2370** 2371** After the application has finished with the result from sqlite3_get_table(), 2372** it must pass the result table pointer to sqlite3_free_table() in order to 2373** release the memory that was malloced. Because of the way the 2374** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2375** function must not try to call [sqlite3_free()] directly. Only 2376** [sqlite3_free_table()] is able to release the memory properly and safely. 2377** 2378** The sqlite3_get_table() interface is implemented as a wrapper around 2379** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2380** to any internal data structures of SQLite. It uses only the public 2381** interface defined here. As a consequence, errors that occur in the 2382** wrapper layer outside of the internal [sqlite3_exec()] call are not 2383** reflected in subsequent calls to [sqlite3_errcode()] or 2384** [sqlite3_errmsg()]. 2385*/ 2386int sqlite3_get_table( 2387 sqlite3 *db, /* An open database */ 2388 const char *zSql, /* SQL to be evaluated */ 2389 char ***pazResult, /* Results of the query */ 2390 int *pnRow, /* Number of result rows written here */ 2391 int *pnColumn, /* Number of result columns written here */ 2392 char **pzErrmsg /* Error msg written here */ 2393); 2394void sqlite3_free_table(char **result); 2395 2396/* 2397** CAPI3REF: Formatted String Printing Functions 2398** 2399** These routines are work-alikes of the "printf()" family of functions 2400** from the standard C library. 2401** These routines understand most of the common K&R formatting options, 2402** plus some additional non-standard formats, detailed below. 2403** Note that some of the more obscure formatting options from recent 2404** C-library standards are omitted from this implementation. 2405** 2406** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2407** results into memory obtained from [sqlite3_malloc()]. 2408** The strings returned by these two routines should be 2409** released by [sqlite3_free()]. ^Both routines return a 2410** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2411** memory to hold the resulting string. 2412** 2413** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2414** the standard C library. The result is written into the 2415** buffer supplied as the second parameter whose size is given by 2416** the first parameter. Note that the order of the 2417** first two parameters is reversed from snprintf().)^ This is an 2418** historical accident that cannot be fixed without breaking 2419** backwards compatibility. ^(Note also that sqlite3_snprintf() 2420** returns a pointer to its buffer instead of the number of 2421** characters actually written into the buffer.)^ We admit that 2422** the number of characters written would be a more useful return 2423** value but we cannot change the implementation of sqlite3_snprintf() 2424** now without breaking compatibility. 2425** 2426** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2427** guarantees that the buffer is always zero-terminated. ^The first 2428** parameter "n" is the total size of the buffer, including space for 2429** the zero terminator. So the longest string that can be completely 2430** written will be n-1 characters. 2431** 2432** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2433** 2434** These routines all implement some additional formatting 2435** options that are useful for constructing SQL statements. 2436** All of the usual printf() formatting options apply. In addition, there 2437** is are "%q", "%Q", "%w" and "%z" options. 2438** 2439** ^(The %q option works like %s in that it substitutes a nul-terminated 2440** string from the argument list. But %q also doubles every '\'' character. 2441** %q is designed for use inside a string literal.)^ By doubling each '\'' 2442** character it escapes that character and allows it to be inserted into 2443** the string. 2444** 2445** For example, assume the string variable zText contains text as follows: 2446** 2447** <blockquote><pre> 2448** char *zText = "It's a happy day!"; 2449** </pre></blockquote> 2450** 2451** One can use this text in an SQL statement as follows: 2452** 2453** <blockquote><pre> 2454** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2455** sqlite3_exec(db, zSQL, 0, 0, 0); 2456** sqlite3_free(zSQL); 2457** </pre></blockquote> 2458** 2459** Because the %q format string is used, the '\'' character in zText 2460** is escaped and the SQL generated is as follows: 2461** 2462** <blockquote><pre> 2463** INSERT INTO table1 VALUES('It''s a happy day!') 2464** </pre></blockquote> 2465** 2466** This is correct. Had we used %s instead of %q, the generated SQL 2467** would have looked like this: 2468** 2469** <blockquote><pre> 2470** INSERT INTO table1 VALUES('It's a happy day!'); 2471** </pre></blockquote> 2472** 2473** This second example is an SQL syntax error. As a general rule you should 2474** always use %q instead of %s when inserting text into a string literal. 2475** 2476** ^(The %Q option works like %q except it also adds single quotes around 2477** the outside of the total string. Additionally, if the parameter in the 2478** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2479** single quotes).)^ So, for example, one could say: 2480** 2481** <blockquote><pre> 2482** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2483** sqlite3_exec(db, zSQL, 0, 0, 0); 2484** sqlite3_free(zSQL); 2485** </pre></blockquote> 2486** 2487** The code above will render a correct SQL statement in the zSQL 2488** variable even if the zText variable is a NULL pointer. 2489** 2490** ^(The "%w" formatting option is like "%q" except that it expects to 2491** be contained within double-quotes instead of single quotes, and it 2492** escapes the double-quote character instead of the single-quote 2493** character.)^ The "%w" formatting option is intended for safely inserting 2494** table and column names into a constructed SQL statement. 2495** 2496** ^(The "%z" formatting option works like "%s" but with the 2497** addition that after the string has been read and copied into 2498** the result, [sqlite3_free()] is called on the input string.)^ 2499*/ 2500char *sqlite3_mprintf(const char*,...); 2501char *sqlite3_vmprintf(const char*, va_list); 2502char *sqlite3_snprintf(int,char*,const char*, ...); 2503char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2504 2505/* 2506** CAPI3REF: Memory Allocation Subsystem 2507** 2508** The SQLite core uses these three routines for all of its own 2509** internal memory allocation needs. "Core" in the previous sentence 2510** does not include operating-system specific VFS implementation. The 2511** Windows VFS uses native malloc() and free() for some operations. 2512** 2513** ^The sqlite3_malloc() routine returns a pointer to a block 2514** of memory at least N bytes in length, where N is the parameter. 2515** ^If sqlite3_malloc() is unable to obtain sufficient free 2516** memory, it returns a NULL pointer. ^If the parameter N to 2517** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2518** a NULL pointer. 2519** 2520** ^The sqlite3_malloc64(N) routine works just like 2521** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2522** of a signed 32-bit integer. 2523** 2524** ^Calling sqlite3_free() with a pointer previously returned 2525** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2526** that it might be reused. ^The sqlite3_free() routine is 2527** a no-op if is called with a NULL pointer. Passing a NULL pointer 2528** to sqlite3_free() is harmless. After being freed, memory 2529** should neither be read nor written. Even reading previously freed 2530** memory might result in a segmentation fault or other severe error. 2531** Memory corruption, a segmentation fault, or other severe error 2532** might result if sqlite3_free() is called with a non-NULL pointer that 2533** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2534** 2535** ^The sqlite3_realloc(X,N) interface attempts to resize a 2536** prior memory allocation X to be at least N bytes. 2537** ^If the X parameter to sqlite3_realloc(X,N) 2538** is a NULL pointer then its behavior is identical to calling 2539** sqlite3_malloc(N). 2540** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2541** negative then the behavior is exactly the same as calling 2542** sqlite3_free(X). 2543** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2544** of at least N bytes in size or NULL if insufficient memory is available. 2545** ^If M is the size of the prior allocation, then min(N,M) bytes 2546** of the prior allocation are copied into the beginning of buffer returned 2547** by sqlite3_realloc(X,N) and the prior allocation is freed. 2548** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2549** prior allocation is not freed. 2550** 2551** ^The sqlite3_realloc64(X,N) interfaces works the same as 2552** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2553** of a 32-bit signed integer. 2554** 2555** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2556** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2557** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2558** ^The value returned by sqlite3_msize(X) might be larger than the number 2559** of bytes requested when X was allocated. ^If X is a NULL pointer then 2560** sqlite3_msize(X) returns zero. If X points to something that is not 2561** the beginning of memory allocation, or if it points to a formerly 2562** valid memory allocation that has now been freed, then the behavior 2563** of sqlite3_msize(X) is undefined and possibly harmful. 2564** 2565** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2566** sqlite3_malloc64(), and sqlite3_realloc64() 2567** is always aligned to at least an 8 byte boundary, or to a 2568** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2569** option is used. 2570** 2571** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2572** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2573** implementation of these routines to be omitted. That capability 2574** is no longer provided. Only built-in memory allocators can be used. 2575** 2576** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2577** the system malloc() and free() directly when converting 2578** filenames between the UTF-8 encoding used by SQLite 2579** and whatever filename encoding is used by the particular Windows 2580** installation. Memory allocation errors were detected, but 2581** they were reported back as [SQLITE_CANTOPEN] or 2582** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2583** 2584** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2585** must be either NULL or else pointers obtained from a prior 2586** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2587** not yet been released. 2588** 2589** The application must not read or write any part of 2590** a block of memory after it has been released using 2591** [sqlite3_free()] or [sqlite3_realloc()]. 2592*/ 2593void *sqlite3_malloc(int); 2594void *sqlite3_malloc64(sqlite3_uint64); 2595void *sqlite3_realloc(void*, int); 2596void *sqlite3_realloc64(void*, sqlite3_uint64); 2597void sqlite3_free(void*); 2598sqlite3_uint64 sqlite3_msize(void*); 2599 2600/* 2601** CAPI3REF: Memory Allocator Statistics 2602** 2603** SQLite provides these two interfaces for reporting on the status 2604** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2605** routines, which form the built-in memory allocation subsystem. 2606** 2607** ^The [sqlite3_memory_used()] routine returns the number of bytes 2608** of memory currently outstanding (malloced but not freed). 2609** ^The [sqlite3_memory_highwater()] routine returns the maximum 2610** value of [sqlite3_memory_used()] since the high-water mark 2611** was last reset. ^The values returned by [sqlite3_memory_used()] and 2612** [sqlite3_memory_highwater()] include any overhead 2613** added by SQLite in its implementation of [sqlite3_malloc()], 2614** but not overhead added by the any underlying system library 2615** routines that [sqlite3_malloc()] may call. 2616** 2617** ^The memory high-water mark is reset to the current value of 2618** [sqlite3_memory_used()] if and only if the parameter to 2619** [sqlite3_memory_highwater()] is true. ^The value returned 2620** by [sqlite3_memory_highwater(1)] is the high-water mark 2621** prior to the reset. 2622*/ 2623sqlite3_int64 sqlite3_memory_used(void); 2624sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2625 2626/* 2627** CAPI3REF: Pseudo-Random Number Generator 2628** 2629** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2630** select random [ROWID | ROWIDs] when inserting new records into a table that 2631** already uses the largest possible [ROWID]. The PRNG is also used for 2632** the build-in random() and randomblob() SQL functions. This interface allows 2633** applications to access the same PRNG for other purposes. 2634** 2635** ^A call to this routine stores N bytes of randomness into buffer P. 2636** ^The P parameter can be a NULL pointer. 2637** 2638** ^If this routine has not been previously called or if the previous 2639** call had N less than one or a NULL pointer for P, then the PRNG is 2640** seeded using randomness obtained from the xRandomness method of 2641** the default [sqlite3_vfs] object. 2642** ^If the previous call to this routine had an N of 1 or more and a 2643** non-NULL P then the pseudo-randomness is generated 2644** internally and without recourse to the [sqlite3_vfs] xRandomness 2645** method. 2646*/ 2647void sqlite3_randomness(int N, void *P); 2648 2649/* 2650** CAPI3REF: Compile-Time Authorization Callbacks 2651** METHOD: sqlite3 2652** 2653** ^This routine registers an authorizer callback with a particular 2654** [database connection], supplied in the first argument. 2655** ^The authorizer callback is invoked as SQL statements are being compiled 2656** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2657** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2658** points during the compilation process, as logic is being created 2659** to perform various actions, the authorizer callback is invoked to 2660** see if those actions are allowed. ^The authorizer callback should 2661** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2662** specific action but allow the SQL statement to continue to be 2663** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2664** rejected with an error. ^If the authorizer callback returns 2665** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2666** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2667** the authorizer will fail with an error message. 2668** 2669** When the callback returns [SQLITE_OK], that means the operation 2670** requested is ok. ^When the callback returns [SQLITE_DENY], the 2671** [sqlite3_prepare_v2()] or equivalent call that triggered the 2672** authorizer will fail with an error message explaining that 2673** access is denied. 2674** 2675** ^The first parameter to the authorizer callback is a copy of the third 2676** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2677** to the callback is an integer [SQLITE_COPY | action code] that specifies 2678** the particular action to be authorized. ^The third through sixth parameters 2679** to the callback are zero-terminated strings that contain additional 2680** details about the action to be authorized. 2681** 2682** ^If the action code is [SQLITE_READ] 2683** and the callback returns [SQLITE_IGNORE] then the 2684** [prepared statement] statement is constructed to substitute 2685** a NULL value in place of the table column that would have 2686** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2687** return can be used to deny an untrusted user access to individual 2688** columns of a table. 2689** ^If the action code is [SQLITE_DELETE] and the callback returns 2690** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2691** [truncate optimization] is disabled and all rows are deleted individually. 2692** 2693** An authorizer is used when [sqlite3_prepare | preparing] 2694** SQL statements from an untrusted source, to ensure that the SQL statements 2695** do not try to access data they are not allowed to see, or that they do not 2696** try to execute malicious statements that damage the database. For 2697** example, an application may allow a user to enter arbitrary 2698** SQL queries for evaluation by a database. But the application does 2699** not want the user to be able to make arbitrary changes to the 2700** database. An authorizer could then be put in place while the 2701** user-entered SQL is being [sqlite3_prepare | prepared] that 2702** disallows everything except [SELECT] statements. 2703** 2704** Applications that need to process SQL from untrusted sources 2705** might also consider lowering resource limits using [sqlite3_limit()] 2706** and limiting database size using the [max_page_count] [PRAGMA] 2707** in addition to using an authorizer. 2708** 2709** ^(Only a single authorizer can be in place on a database connection 2710** at a time. Each call to sqlite3_set_authorizer overrides the 2711** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2712** The authorizer is disabled by default. 2713** 2714** The authorizer callback must not do anything that will modify 2715** the database connection that invoked the authorizer callback. 2716** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2717** database connections for the meaning of "modify" in this paragraph. 2718** 2719** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2720** statement might be re-prepared during [sqlite3_step()] due to a 2721** schema change. Hence, the application should ensure that the 2722** correct authorizer callback remains in place during the [sqlite3_step()]. 2723** 2724** ^Note that the authorizer callback is invoked only during 2725** [sqlite3_prepare()] or its variants. Authorization is not 2726** performed during statement evaluation in [sqlite3_step()], unless 2727** as stated in the previous paragraph, sqlite3_step() invokes 2728** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2729*/ 2730int sqlite3_set_authorizer( 2731 sqlite3*, 2732 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2733 void *pUserData 2734); 2735 2736/* 2737** CAPI3REF: Authorizer Return Codes 2738** 2739** The [sqlite3_set_authorizer | authorizer callback function] must 2740** return either [SQLITE_OK] or one of these two constants in order 2741** to signal SQLite whether or not the action is permitted. See the 2742** [sqlite3_set_authorizer | authorizer documentation] for additional 2743** information. 2744** 2745** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2746** returned from the [sqlite3_vtab_on_conflict()] interface. 2747*/ 2748#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2749#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2750 2751/* 2752** CAPI3REF: Authorizer Action Codes 2753** 2754** The [sqlite3_set_authorizer()] interface registers a callback function 2755** that is invoked to authorize certain SQL statement actions. The 2756** second parameter to the callback is an integer code that specifies 2757** what action is being authorized. These are the integer action codes that 2758** the authorizer callback may be passed. 2759** 2760** These action code values signify what kind of operation is to be 2761** authorized. The 3rd and 4th parameters to the authorization 2762** callback function will be parameters or NULL depending on which of these 2763** codes is used as the second parameter. ^(The 5th parameter to the 2764** authorizer callback is the name of the database ("main", "temp", 2765** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2766** is the name of the inner-most trigger or view that is responsible for 2767** the access attempt or NULL if this access attempt is directly from 2768** top-level SQL code. 2769*/ 2770/******************************************* 3rd ************ 4th ***********/ 2771#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2772#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2773#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2774#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2775#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2776#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2777#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2778#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2779#define SQLITE_DELETE 9 /* Table Name NULL */ 2780#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2781#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2782#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2783#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2784#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2785#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2786#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2787#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2788#define SQLITE_INSERT 18 /* Table Name NULL */ 2789#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2790#define SQLITE_READ 20 /* Table Name Column Name */ 2791#define SQLITE_SELECT 21 /* NULL NULL */ 2792#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2793#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2794#define SQLITE_ATTACH 24 /* Filename NULL */ 2795#define SQLITE_DETACH 25 /* Database Name NULL */ 2796#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2797#define SQLITE_REINDEX 27 /* Index Name NULL */ 2798#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2799#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2800#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2801#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2802#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2803#define SQLITE_COPY 0 /* No longer used */ 2804#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2805 2806/* 2807** CAPI3REF: Tracing And Profiling Functions 2808** METHOD: sqlite3 2809** 2810** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 2811** instead of the routines described here. 2812** 2813** These routines register callback functions that can be used for 2814** tracing and profiling the execution of SQL statements. 2815** 2816** ^The callback function registered by sqlite3_trace() is invoked at 2817** various times when an SQL statement is being run by [sqlite3_step()]. 2818** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2819** SQL statement text as the statement first begins executing. 2820** ^(Additional sqlite3_trace() callbacks might occur 2821** as each triggered subprogram is entered. The callbacks for triggers 2822** contain a UTF-8 SQL comment that identifies the trigger.)^ 2823** 2824** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2825** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2826** 2827** ^The callback function registered by sqlite3_profile() is invoked 2828** as each SQL statement finishes. ^The profile callback contains 2829** the original statement text and an estimate of wall-clock time 2830** of how long that statement took to run. ^The profile callback 2831** time is in units of nanoseconds, however the current implementation 2832** is only capable of millisecond resolution so the six least significant 2833** digits in the time are meaningless. Future versions of SQLite 2834** might provide greater resolution on the profiler callback. The 2835** sqlite3_profile() function is considered experimental and is 2836** subject to change in future versions of SQLite. 2837*/ 2838SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 2839 void(*xTrace)(void*,const char*), void*); 2840SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 2841 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2842 2843/* 2844** CAPI3REF: SQL Trace Event Codes 2845** KEYWORDS: SQLITE_TRACE 2846** 2847** These constants identify classes of events that can be monitored 2848** using the [sqlite3_trace_v2()] tracing logic. The third argument 2849** to [sqlite3_trace_v2()] is an OR-ed combination of one or more of 2850** the following constants. ^The first argument to the trace callback 2851** is one of the following constants. 2852** 2853** New tracing constants may be added in future releases. 2854** 2855** ^A trace callback has four arguments: xCallback(T,C,P,X). 2856** ^The T argument is one of the integer type codes above. 2857** ^The C argument is a copy of the context pointer passed in as the 2858** fourth argument to [sqlite3_trace_v2()]. 2859** The P and X arguments are pointers whose meanings depend on T. 2860** 2861** <dl> 2862** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 2863** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 2864** first begins running and possibly at other times during the 2865** execution of the prepared statement, such as at the start of each 2866** trigger subprogram. ^The P argument is a pointer to the 2867** [prepared statement]. ^The X argument is a pointer to a string which 2868** is the unexpanded SQL text of the prepared statement or an SQL comment 2869** that indicates the invocation of a trigger. ^The callback can compute 2870** the same text that would have been returned by the legacy [sqlite3_trace()] 2871** interface by using the X argument when X begins with "--" and invoking 2872** [sqlite3_expanded_sql(P)] otherwise. 2873** 2874** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 2875** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 2876** information as is provided by the [sqlite3_profile()] callback. 2877** ^The P argument is a pointer to the [prepared statement] and the 2878** X argument points to a 64-bit integer which is the estimated of 2879** the number of nanosecond that the prepared statement took to run. 2880** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 2881** 2882** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 2883** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 2884** statement generates a single row of result. 2885** ^The P argument is a pointer to the [prepared statement] and the 2886** X argument is unused. 2887** 2888** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 2889** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 2890** connection closes. 2891** ^The P argument is a pointer to the [database connection] object 2892** and the X argument is unused. 2893** </dl> 2894*/ 2895#define SQLITE_TRACE_STMT 0x01 2896#define SQLITE_TRACE_PROFILE 0x02 2897#define SQLITE_TRACE_ROW 0x04 2898#define SQLITE_TRACE_CLOSE 0x08 2899 2900/* 2901** CAPI3REF: SQL Trace Hook 2902** METHOD: sqlite3 2903** 2904** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 2905** function X against [database connection] D, using property mask M 2906** and context pointer P. ^If the X callback is 2907** NULL or if the M mask is zero, then tracing is disabled. The 2908** M argument should be the bitwise OR-ed combination of 2909** zero or more [SQLITE_TRACE] constants. 2910** 2911** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 2912** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 2913** 2914** ^The X callback is invoked whenever any of the events identified by 2915** mask M occur. ^The integer return value from the callback is currently 2916** ignored, though this may change in future releases. Callback 2917** implementations should return zero to ensure future compatibility. 2918** 2919** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 2920** ^The T argument is one of the [SQLITE_TRACE] 2921** constants to indicate why the callback was invoked. 2922** ^The C argument is a copy of the context pointer. 2923** The P and X arguments are pointers whose meanings depend on T. 2924** 2925** The sqlite3_trace_v2() interface is intended to replace the legacy 2926** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 2927** are deprecated. 2928*/ 2929int sqlite3_trace_v2( 2930 sqlite3*, 2931 unsigned uMask, 2932 int(*xCallback)(unsigned,void*,void*,void*), 2933 void *pCtx 2934); 2935 2936/* 2937** CAPI3REF: Query Progress Callbacks 2938** METHOD: sqlite3 2939** 2940** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2941** function X to be invoked periodically during long running calls to 2942** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2943** database connection D. An example use for this 2944** interface is to keep a GUI updated during a large query. 2945** 2946** ^The parameter P is passed through as the only parameter to the 2947** callback function X. ^The parameter N is the approximate number of 2948** [virtual machine instructions] that are evaluated between successive 2949** invocations of the callback X. ^If N is less than one then the progress 2950** handler is disabled. 2951** 2952** ^Only a single progress handler may be defined at one time per 2953** [database connection]; setting a new progress handler cancels the 2954** old one. ^Setting parameter X to NULL disables the progress handler. 2955** ^The progress handler is also disabled by setting N to a value less 2956** than 1. 2957** 2958** ^If the progress callback returns non-zero, the operation is 2959** interrupted. This feature can be used to implement a 2960** "Cancel" button on a GUI progress dialog box. 2961** 2962** The progress handler callback must not do anything that will modify 2963** the database connection that invoked the progress handler. 2964** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2965** database connections for the meaning of "modify" in this paragraph. 2966** 2967*/ 2968void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2969 2970/* 2971** CAPI3REF: Opening A New Database Connection 2972** CONSTRUCTOR: sqlite3 2973** 2974** ^These routines open an SQLite database file as specified by the 2975** filename argument. ^The filename argument is interpreted as UTF-8 for 2976** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2977** order for sqlite3_open16(). ^(A [database connection] handle is usually 2978** returned in *ppDb, even if an error occurs. The only exception is that 2979** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2980** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2981** object.)^ ^(If the database is opened (and/or created) successfully, then 2982** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2983** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2984** an English language description of the error following a failure of any 2985** of the sqlite3_open() routines. 2986** 2987** ^The default encoding will be UTF-8 for databases created using 2988** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 2989** created using sqlite3_open16() will be UTF-16 in the native byte order. 2990** 2991** Whether or not an error occurs when it is opened, resources 2992** associated with the [database connection] handle should be released by 2993** passing it to [sqlite3_close()] when it is no longer required. 2994** 2995** The sqlite3_open_v2() interface works like sqlite3_open() 2996** except that it accepts two additional parameters for additional control 2997** over the new database connection. ^(The flags parameter to 2998** sqlite3_open_v2() can take one of 2999** the following three values, optionally combined with the 3000** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 3001** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 3002** 3003** <dl> 3004** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3005** <dd>The database is opened in read-only mode. If the database does not 3006** already exist, an error is returned.</dd>)^ 3007** 3008** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3009** <dd>The database is opened for reading and writing if possible, or reading 3010** only if the file is write protected by the operating system. In either 3011** case the database must already exist, otherwise an error is returned.</dd>)^ 3012** 3013** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3014** <dd>The database is opened for reading and writing, and is created if 3015** it does not already exist. This is the behavior that is always used for 3016** sqlite3_open() and sqlite3_open16().</dd>)^ 3017** </dl> 3018** 3019** If the 3rd parameter to sqlite3_open_v2() is not one of the 3020** combinations shown above optionally combined with other 3021** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3022** then the behavior is undefined. 3023** 3024** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 3025** opens in the multi-thread [threading mode] as long as the single-thread 3026** mode has not been set at compile-time or start-time. ^If the 3027** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 3028** in the serialized [threading mode] unless single-thread was 3029** previously selected at compile-time or start-time. 3030** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 3031** eligible to use [shared cache mode], regardless of whether or not shared 3032** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 3033** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 3034** participate in [shared cache mode] even if it is enabled. 3035** 3036** ^The fourth parameter to sqlite3_open_v2() is the name of the 3037** [sqlite3_vfs] object that defines the operating system interface that 3038** the new database connection should use. ^If the fourth parameter is 3039** a NULL pointer then the default [sqlite3_vfs] object is used. 3040** 3041** ^If the filename is ":memory:", then a private, temporary in-memory database 3042** is created for the connection. ^This in-memory database will vanish when 3043** the database connection is closed. Future versions of SQLite might 3044** make use of additional special filenames that begin with the ":" character. 3045** It is recommended that when a database filename actually does begin with 3046** a ":" character you should prefix the filename with a pathname such as 3047** "./" to avoid ambiguity. 3048** 3049** ^If the filename is an empty string, then a private, temporary 3050** on-disk database will be created. ^This private database will be 3051** automatically deleted as soon as the database connection is closed. 3052** 3053** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3054** 3055** ^If [URI filename] interpretation is enabled, and the filename argument 3056** begins with "file:", then the filename is interpreted as a URI. ^URI 3057** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3058** set in the fourth argument to sqlite3_open_v2(), or if it has 3059** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3060** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3061** As of SQLite version 3.7.7, URI filename interpretation is turned off 3062** by default, but future releases of SQLite might enable URI filename 3063** interpretation by default. See "[URI filenames]" for additional 3064** information. 3065** 3066** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3067** authority, then it must be either an empty string or the string 3068** "localhost". ^If the authority is not an empty string or "localhost", an 3069** error is returned to the caller. ^The fragment component of a URI, if 3070** present, is ignored. 3071** 3072** ^SQLite uses the path component of the URI as the name of the disk file 3073** which contains the database. ^If the path begins with a '/' character, 3074** then it is interpreted as an absolute path. ^If the path does not begin 3075** with a '/' (meaning that the authority section is omitted from the URI) 3076** then the path is interpreted as a relative path. 3077** ^(On windows, the first component of an absolute path 3078** is a drive specification (e.g. "C:").)^ 3079** 3080** [[core URI query parameters]] 3081** The query component of a URI may contain parameters that are interpreted 3082** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3083** SQLite and its built-in [VFSes] interpret the 3084** following query parameters: 3085** 3086** <ul> 3087** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3088** a VFS object that provides the operating system interface that should 3089** be used to access the database file on disk. ^If this option is set to 3090** an empty string the default VFS object is used. ^Specifying an unknown 3091** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3092** present, then the VFS specified by the option takes precedence over 3093** the value passed as the fourth parameter to sqlite3_open_v2(). 3094** 3095** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3096** "rwc", or "memory". Attempting to set it to any other value is 3097** an error)^. 3098** ^If "ro" is specified, then the database is opened for read-only 3099** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3100** third argument to sqlite3_open_v2(). ^If the mode option is set to 3101** "rw", then the database is opened for read-write (but not create) 3102** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3103** been set. ^Value "rwc" is equivalent to setting both 3104** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3105** set to "memory" then a pure [in-memory database] that never reads 3106** or writes from disk is used. ^It is an error to specify a value for 3107** the mode parameter that is less restrictive than that specified by 3108** the flags passed in the third parameter to sqlite3_open_v2(). 3109** 3110** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3111** "private". ^Setting it to "shared" is equivalent to setting the 3112** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3113** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3114** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3115** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3116** a URI filename, its value overrides any behavior requested by setting 3117** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3118** 3119** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3120** [powersafe overwrite] property does or does not apply to the 3121** storage media on which the database file resides. 3122** 3123** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3124** which if set disables file locking in rollback journal modes. This 3125** is useful for accessing a database on a filesystem that does not 3126** support locking. Caution: Database corruption might result if two 3127** or more processes write to the same database and any one of those 3128** processes uses nolock=1. 3129** 3130** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3131** parameter that indicates that the database file is stored on 3132** read-only media. ^When immutable is set, SQLite assumes that the 3133** database file cannot be changed, even by a process with higher 3134** privilege, and so the database is opened read-only and all locking 3135** and change detection is disabled. Caution: Setting the immutable 3136** property on a database file that does in fact change can result 3137** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3138** See also: [SQLITE_IOCAP_IMMUTABLE]. 3139** 3140** </ul> 3141** 3142** ^Specifying an unknown parameter in the query component of a URI is not an 3143** error. Future versions of SQLite might understand additional query 3144** parameters. See "[query parameters with special meaning to SQLite]" for 3145** additional information. 3146** 3147** [[URI filename examples]] <h3>URI filename examples</h3> 3148** 3149** <table border="1" align=center cellpadding=5> 3150** <tr><th> URI filenames <th> Results 3151** <tr><td> file:data.db <td> 3152** Open the file "data.db" in the current directory. 3153** <tr><td> file:/home/fred/data.db<br> 3154** file:///home/fred/data.db <br> 3155** file://localhost/home/fred/data.db <br> <td> 3156** Open the database file "/home/fred/data.db". 3157** <tr><td> file://darkstar/home/fred/data.db <td> 3158** An error. "darkstar" is not a recognized authority. 3159** <tr><td style="white-space:nowrap"> 3160** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3161** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3162** C:. Note that the %20 escaping in this example is not strictly 3163** necessary - space characters can be used literally 3164** in URI filenames. 3165** <tr><td> file:data.db?mode=ro&cache=private <td> 3166** Open file "data.db" in the current directory for read-only access. 3167** Regardless of whether or not shared-cache mode is enabled by 3168** default, use a private cache. 3169** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3170** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3171** that uses dot-files in place of posix advisory locking. 3172** <tr><td> file:data.db?mode=readonly <td> 3173** An error. "readonly" is not a valid option for the "mode" parameter. 3174** </table> 3175** 3176** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3177** query components of a URI. A hexadecimal escape sequence consists of a 3178** percent sign - "%" - followed by exactly two hexadecimal digits 3179** specifying an octet value. ^Before the path or query components of a 3180** URI filename are interpreted, they are encoded using UTF-8 and all 3181** hexadecimal escape sequences replaced by a single byte containing the 3182** corresponding octet. If this process generates an invalid UTF-8 encoding, 3183** the results are undefined. 3184** 3185** <b>Note to Windows users:</b> The encoding used for the filename argument 3186** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3187** codepage is currently defined. Filenames containing international 3188** characters must be converted to UTF-8 prior to passing them into 3189** sqlite3_open() or sqlite3_open_v2(). 3190** 3191** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3192** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3193** features that require the use of temporary files may fail. 3194** 3195** See also: [sqlite3_temp_directory] 3196*/ 3197int sqlite3_open( 3198 const char *filename, /* Database filename (UTF-8) */ 3199 sqlite3 **ppDb /* OUT: SQLite db handle */ 3200); 3201int sqlite3_open16( 3202 const void *filename, /* Database filename (UTF-16) */ 3203 sqlite3 **ppDb /* OUT: SQLite db handle */ 3204); 3205int sqlite3_open_v2( 3206 const char *filename, /* Database filename (UTF-8) */ 3207 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3208 int flags, /* Flags */ 3209 const char *zVfs /* Name of VFS module to use */ 3210); 3211 3212/* 3213** CAPI3REF: Obtain Values For URI Parameters 3214** 3215** These are utility routines, useful to VFS implementations, that check 3216** to see if a database file was a URI that contained a specific query 3217** parameter, and if so obtains the value of that query parameter. 3218** 3219** If F is the database filename pointer passed into the xOpen() method of 3220** a VFS implementation when the flags parameter to xOpen() has one or 3221** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3222** P is the name of the query parameter, then 3223** sqlite3_uri_parameter(F,P) returns the value of the P 3224** parameter if it exists or a NULL pointer if P does not appear as a 3225** query parameter on F. If P is a query parameter of F 3226** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3227** a pointer to an empty string. 3228** 3229** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3230** parameter and returns true (1) or false (0) according to the value 3231** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3232** value of query parameter P is one of "yes", "true", or "on" in any 3233** case or if the value begins with a non-zero number. The 3234** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3235** query parameter P is one of "no", "false", or "off" in any case or 3236** if the value begins with a numeric zero. If P is not a query 3237** parameter on F or if the value of P is does not match any of the 3238** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3239** 3240** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3241** 64-bit signed integer and returns that integer, or D if P does not 3242** exist. If the value of P is something other than an integer, then 3243** zero is returned. 3244** 3245** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3246** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3247** is not a database file pathname pointer that SQLite passed into the xOpen 3248** VFS method, then the behavior of this routine is undefined and probably 3249** undesirable. 3250*/ 3251const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3252int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3253sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3254 3255 3256/* 3257** CAPI3REF: Error Codes And Messages 3258** METHOD: sqlite3 3259** 3260** ^If the most recent sqlite3_* API call associated with 3261** [database connection] D failed, then the sqlite3_errcode(D) interface 3262** returns the numeric [result code] or [extended result code] for that 3263** API call. 3264** If the most recent API call was successful, 3265** then the return value from sqlite3_errcode() is undefined. 3266** ^The sqlite3_extended_errcode() 3267** interface is the same except that it always returns the 3268** [extended result code] even when extended result codes are 3269** disabled. 3270** 3271** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3272** text that describes the error, as either UTF-8 or UTF-16 respectively. 3273** ^(Memory to hold the error message string is managed internally. 3274** The application does not need to worry about freeing the result. 3275** However, the error string might be overwritten or deallocated by 3276** subsequent calls to other SQLite interface functions.)^ 3277** 3278** ^The sqlite3_errstr() interface returns the English-language text 3279** that describes the [result code], as UTF-8. 3280** ^(Memory to hold the error message string is managed internally 3281** and must not be freed by the application)^. 3282** 3283** When the serialized [threading mode] is in use, it might be the 3284** case that a second error occurs on a separate thread in between 3285** the time of the first error and the call to these interfaces. 3286** When that happens, the second error will be reported since these 3287** interfaces always report the most recent result. To avoid 3288** this, each thread can obtain exclusive use of the [database connection] D 3289** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3290** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3291** all calls to the interfaces listed here are completed. 3292** 3293** If an interface fails with SQLITE_MISUSE, that means the interface 3294** was invoked incorrectly by the application. In that case, the 3295** error code and message may or may not be set. 3296*/ 3297int sqlite3_errcode(sqlite3 *db); 3298int sqlite3_extended_errcode(sqlite3 *db); 3299const char *sqlite3_errmsg(sqlite3*); 3300const void *sqlite3_errmsg16(sqlite3*); 3301const char *sqlite3_errstr(int); 3302 3303/* 3304** CAPI3REF: Prepared Statement Object 3305** KEYWORDS: {prepared statement} {prepared statements} 3306** 3307** An instance of this object represents a single SQL statement that 3308** has been compiled into binary form and is ready to be evaluated. 3309** 3310** Think of each SQL statement as a separate computer program. The 3311** original SQL text is source code. A prepared statement object 3312** is the compiled object code. All SQL must be converted into a 3313** prepared statement before it can be run. 3314** 3315** The life-cycle of a prepared statement object usually goes like this: 3316** 3317** <ol> 3318** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3319** <li> Bind values to [parameters] using the sqlite3_bind_*() 3320** interfaces. 3321** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3322** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3323** to step 2. Do this zero or more times. 3324** <li> Destroy the object using [sqlite3_finalize()]. 3325** </ol> 3326*/ 3327typedef struct sqlite3_stmt sqlite3_stmt; 3328 3329/* 3330** CAPI3REF: Run-time Limits 3331** METHOD: sqlite3 3332** 3333** ^(This interface allows the size of various constructs to be limited 3334** on a connection by connection basis. The first parameter is the 3335** [database connection] whose limit is to be set or queried. The 3336** second parameter is one of the [limit categories] that define a 3337** class of constructs to be size limited. The third parameter is the 3338** new limit for that construct.)^ 3339** 3340** ^If the new limit is a negative number, the limit is unchanged. 3341** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3342** [limits | hard upper bound] 3343** set at compile-time by a C preprocessor macro called 3344** [limits | SQLITE_MAX_<i>NAME</i>]. 3345** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3346** ^Attempts to increase a limit above its hard upper bound are 3347** silently truncated to the hard upper bound. 3348** 3349** ^Regardless of whether or not the limit was changed, the 3350** [sqlite3_limit()] interface returns the prior value of the limit. 3351** ^Hence, to find the current value of a limit without changing it, 3352** simply invoke this interface with the third parameter set to -1. 3353** 3354** Run-time limits are intended for use in applications that manage 3355** both their own internal database and also databases that are controlled 3356** by untrusted external sources. An example application might be a 3357** web browser that has its own databases for storing history and 3358** separate databases controlled by JavaScript applications downloaded 3359** off the Internet. The internal databases can be given the 3360** large, default limits. Databases managed by external sources can 3361** be given much smaller limits designed to prevent a denial of service 3362** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3363** interface to further control untrusted SQL. The size of the database 3364** created by an untrusted script can be contained using the 3365** [max_page_count] [PRAGMA]. 3366** 3367** New run-time limit categories may be added in future releases. 3368*/ 3369int sqlite3_limit(sqlite3*, int id, int newVal); 3370 3371/* 3372** CAPI3REF: Run-Time Limit Categories 3373** KEYWORDS: {limit category} {*limit categories} 3374** 3375** These constants define various performance limits 3376** that can be lowered at run-time using [sqlite3_limit()]. 3377** The synopsis of the meanings of the various limits is shown below. 3378** Additional information is available at [limits | Limits in SQLite]. 3379** 3380** <dl> 3381** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3382** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3383** 3384** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3385** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3386** 3387** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3388** <dd>The maximum number of columns in a table definition or in the 3389** result set of a [SELECT] or the maximum number of columns in an index 3390** or in an ORDER BY or GROUP BY clause.</dd>)^ 3391** 3392** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3393** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3394** 3395** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3396** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3397** 3398** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3399** <dd>The maximum number of instructions in a virtual machine program 3400** used to implement an SQL statement. This limit is not currently 3401** enforced, though that might be added in some future release of 3402** SQLite.</dd>)^ 3403** 3404** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3405** <dd>The maximum number of arguments on a function.</dd>)^ 3406** 3407** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3408** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3409** 3410** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3411** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3412** <dd>The maximum length of the pattern argument to the [LIKE] or 3413** [GLOB] operators.</dd>)^ 3414** 3415** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3416** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3417** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3418** 3419** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3420** <dd>The maximum depth of recursion for triggers.</dd>)^ 3421** 3422** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3423** <dd>The maximum number of auxiliary worker threads that a single 3424** [prepared statement] may start.</dd>)^ 3425** </dl> 3426*/ 3427#define SQLITE_LIMIT_LENGTH 0 3428#define SQLITE_LIMIT_SQL_LENGTH 1 3429#define SQLITE_LIMIT_COLUMN 2 3430#define SQLITE_LIMIT_EXPR_DEPTH 3 3431#define SQLITE_LIMIT_COMPOUND_SELECT 4 3432#define SQLITE_LIMIT_VDBE_OP 5 3433#define SQLITE_LIMIT_FUNCTION_ARG 6 3434#define SQLITE_LIMIT_ATTACHED 7 3435#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3436#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3437#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3438#define SQLITE_LIMIT_WORKER_THREADS 11 3439 3440/* 3441** CAPI3REF: Compiling An SQL Statement 3442** KEYWORDS: {SQL statement compiler} 3443** METHOD: sqlite3 3444** CONSTRUCTOR: sqlite3_stmt 3445** 3446** To execute an SQL query, it must first be compiled into a byte-code 3447** program using one of these routines. 3448** 3449** The first argument, "db", is a [database connection] obtained from a 3450** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3451** [sqlite3_open16()]. The database connection must not have been closed. 3452** 3453** The second argument, "zSql", is the statement to be compiled, encoded 3454** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 3455** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 3456** use UTF-16. 3457** 3458** ^If the nByte argument is negative, then zSql is read up to the 3459** first zero terminator. ^If nByte is positive, then it is the 3460** number of bytes read from zSql. ^If nByte is zero, then no prepared 3461** statement is generated. 3462** If the caller knows that the supplied string is nul-terminated, then 3463** there is a small performance advantage to passing an nByte parameter that 3464** is the number of bytes in the input string <i>including</i> 3465** the nul-terminator. 3466** 3467** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3468** past the end of the first SQL statement in zSql. These routines only 3469** compile the first statement in zSql, so *pzTail is left pointing to 3470** what remains uncompiled. 3471** 3472** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3473** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3474** to NULL. ^If the input text contains no SQL (if the input is an empty 3475** string or a comment) then *ppStmt is set to NULL. 3476** The calling procedure is responsible for deleting the compiled 3477** SQL statement using [sqlite3_finalize()] after it has finished with it. 3478** ppStmt may not be NULL. 3479** 3480** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3481** otherwise an [error code] is returned. 3482** 3483** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 3484** recommended for all new programs. The two older interfaces are retained 3485** for backwards compatibility, but their use is discouraged. 3486** ^In the "v2" interfaces, the prepared statement 3487** that is returned (the [sqlite3_stmt] object) contains a copy of the 3488** original SQL text. This causes the [sqlite3_step()] interface to 3489** behave differently in three ways: 3490** 3491** <ol> 3492** <li> 3493** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3494** always used to do, [sqlite3_step()] will automatically recompile the SQL 3495** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3496** retries will occur before sqlite3_step() gives up and returns an error. 3497** </li> 3498** 3499** <li> 3500** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3501** [error codes] or [extended error codes]. ^The legacy behavior was that 3502** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3503** and the application would have to make a second call to [sqlite3_reset()] 3504** in order to find the underlying cause of the problem. With the "v2" prepare 3505** interfaces, the underlying reason for the error is returned immediately. 3506** </li> 3507** 3508** <li> 3509** ^If the specific value bound to [parameter | host parameter] in the 3510** WHERE clause might influence the choice of query plan for a statement, 3511** then the statement will be automatically recompiled, as if there had been 3512** a schema change, on the first [sqlite3_step()] call following any change 3513** to the [sqlite3_bind_text | bindings] of that [parameter]. 3514** ^The specific value of WHERE-clause [parameter] might influence the 3515** choice of query plan if the parameter is the left-hand side of a [LIKE] 3516** or [GLOB] operator or if the parameter is compared to an indexed column 3517** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3518** </li> 3519** </ol> 3520*/ 3521int sqlite3_prepare( 3522 sqlite3 *db, /* Database handle */ 3523 const char *zSql, /* SQL statement, UTF-8 encoded */ 3524 int nByte, /* Maximum length of zSql in bytes. */ 3525 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3526 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3527); 3528int sqlite3_prepare_v2( 3529 sqlite3 *db, /* Database handle */ 3530 const char *zSql, /* SQL statement, UTF-8 encoded */ 3531 int nByte, /* Maximum length of zSql in bytes. */ 3532 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3533 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3534); 3535int sqlite3_prepare16( 3536 sqlite3 *db, /* Database handle */ 3537 const void *zSql, /* SQL statement, UTF-16 encoded */ 3538 int nByte, /* Maximum length of zSql in bytes. */ 3539 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3540 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3541); 3542int sqlite3_prepare16_v2( 3543 sqlite3 *db, /* Database handle */ 3544 const void *zSql, /* SQL statement, UTF-16 encoded */ 3545 int nByte, /* Maximum length of zSql in bytes. */ 3546 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3547 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3548); 3549 3550/* 3551** CAPI3REF: Retrieving Statement SQL 3552** METHOD: sqlite3_stmt 3553** 3554** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 3555** SQL text used to create [prepared statement] P if P was 3556** created by either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 3557** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 3558** string containing the SQL text of prepared statement P with 3559** [bound parameters] expanded. 3560** 3561** ^(For example, if a prepared statement is created using the SQL 3562** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 3563** and parameter :xyz is unbound, then sqlite3_sql() will return 3564** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 3565** will return "SELECT 2345,NULL".)^ 3566** 3567** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 3568** is available to hold the result, or if the result would exceed the 3569** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 3570** 3571** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 3572** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 3573** option causes sqlite3_expanded_sql() to always return NULL. 3574** 3575** ^The string returned by sqlite3_sql(P) is managed by SQLite and is 3576** automatically freed when the prepared statement is finalized. 3577** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 3578** is obtained from [sqlite3_malloc()] and must be free by the application 3579** by passing it to [sqlite3_free()]. 3580*/ 3581const char *sqlite3_sql(sqlite3_stmt *pStmt); 3582char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 3583 3584/* 3585** CAPI3REF: Determine If An SQL Statement Writes The Database 3586** METHOD: sqlite3_stmt 3587** 3588** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3589** and only if the [prepared statement] X makes no direct changes to 3590** the content of the database file. 3591** 3592** Note that [application-defined SQL functions] or 3593** [virtual tables] might change the database indirectly as a side effect. 3594** ^(For example, if an application defines a function "eval()" that 3595** calls [sqlite3_exec()], then the following SQL statement would 3596** change the database file through side-effects: 3597** 3598** <blockquote><pre> 3599** SELECT eval('DELETE FROM t1') FROM t2; 3600** </pre></blockquote> 3601** 3602** But because the [SELECT] statement does not change the database file 3603** directly, sqlite3_stmt_readonly() would still return true.)^ 3604** 3605** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3606** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3607** since the statements themselves do not actually modify the database but 3608** rather they control the timing of when other statements modify the 3609** database. ^The [ATTACH] and [DETACH] statements also cause 3610** sqlite3_stmt_readonly() to return true since, while those statements 3611** change the configuration of a database connection, they do not make 3612** changes to the content of the database files on disk. 3613*/ 3614int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3615 3616/* 3617** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3618** METHOD: sqlite3_stmt 3619** 3620** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3621** [prepared statement] S has been stepped at least once using 3622** [sqlite3_step(S)] but has neither run to completion (returned 3623** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3624** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3625** interface returns false if S is a NULL pointer. If S is not a 3626** NULL pointer and is not a pointer to a valid [prepared statement] 3627** object, then the behavior is undefined and probably undesirable. 3628** 3629** This interface can be used in combination [sqlite3_next_stmt()] 3630** to locate all prepared statements associated with a database 3631** connection that are in need of being reset. This can be used, 3632** for example, in diagnostic routines to search for prepared 3633** statements that are holding a transaction open. 3634*/ 3635int sqlite3_stmt_busy(sqlite3_stmt*); 3636 3637/* 3638** CAPI3REF: Dynamically Typed Value Object 3639** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3640** 3641** SQLite uses the sqlite3_value object to represent all values 3642** that can be stored in a database table. SQLite uses dynamic typing 3643** for the values it stores. ^Values stored in sqlite3_value objects 3644** can be integers, floating point values, strings, BLOBs, or NULL. 3645** 3646** An sqlite3_value object may be either "protected" or "unprotected". 3647** Some interfaces require a protected sqlite3_value. Other interfaces 3648** will accept either a protected or an unprotected sqlite3_value. 3649** Every interface that accepts sqlite3_value arguments specifies 3650** whether or not it requires a protected sqlite3_value. The 3651** [sqlite3_value_dup()] interface can be used to construct a new 3652** protected sqlite3_value from an unprotected sqlite3_value. 3653** 3654** The terms "protected" and "unprotected" refer to whether or not 3655** a mutex is held. An internal mutex is held for a protected 3656** sqlite3_value object but no mutex is held for an unprotected 3657** sqlite3_value object. If SQLite is compiled to be single-threaded 3658** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3659** or if SQLite is run in one of reduced mutex modes 3660** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3661** then there is no distinction between protected and unprotected 3662** sqlite3_value objects and they can be used interchangeably. However, 3663** for maximum code portability it is recommended that applications 3664** still make the distinction between protected and unprotected 3665** sqlite3_value objects even when not strictly required. 3666** 3667** ^The sqlite3_value objects that are passed as parameters into the 3668** implementation of [application-defined SQL functions] are protected. 3669** ^The sqlite3_value object returned by 3670** [sqlite3_column_value()] is unprotected. 3671** Unprotected sqlite3_value objects may only be used with 3672** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3673** The [sqlite3_value_blob | sqlite3_value_type()] family of 3674** interfaces require protected sqlite3_value objects. 3675*/ 3676typedef struct Mem sqlite3_value; 3677 3678/* 3679** CAPI3REF: SQL Function Context Object 3680** 3681** The context in which an SQL function executes is stored in an 3682** sqlite3_context object. ^A pointer to an sqlite3_context object 3683** is always first parameter to [application-defined SQL functions]. 3684** The application-defined SQL function implementation will pass this 3685** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3686** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3687** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3688** and/or [sqlite3_set_auxdata()]. 3689*/ 3690typedef struct sqlite3_context sqlite3_context; 3691 3692/* 3693** CAPI3REF: Binding Values To Prepared Statements 3694** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3695** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3696** METHOD: sqlite3_stmt 3697** 3698** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3699** literals may be replaced by a [parameter] that matches one of following 3700** templates: 3701** 3702** <ul> 3703** <li> ? 3704** <li> ?NNN 3705** <li> :VVV 3706** <li> @VVV 3707** <li> $VVV 3708** </ul> 3709** 3710** In the templates above, NNN represents an integer literal, 3711** and VVV represents an alphanumeric identifier.)^ ^The values of these 3712** parameters (also called "host parameter names" or "SQL parameters") 3713** can be set using the sqlite3_bind_*() routines defined here. 3714** 3715** ^The first argument to the sqlite3_bind_*() routines is always 3716** a pointer to the [sqlite3_stmt] object returned from 3717** [sqlite3_prepare_v2()] or its variants. 3718** 3719** ^The second argument is the index of the SQL parameter to be set. 3720** ^The leftmost SQL parameter has an index of 1. ^When the same named 3721** SQL parameter is used more than once, second and subsequent 3722** occurrences have the same index as the first occurrence. 3723** ^The index for named parameters can be looked up using the 3724** [sqlite3_bind_parameter_index()] API if desired. ^The index 3725** for "?NNN" parameters is the value of NNN. 3726** ^The NNN value must be between 1 and the [sqlite3_limit()] 3727** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3728** 3729** ^The third argument is the value to bind to the parameter. 3730** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3731** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3732** is ignored and the end result is the same as sqlite3_bind_null(). 3733** 3734** ^(In those routines that have a fourth argument, its value is the 3735** number of bytes in the parameter. To be clear: the value is the 3736** number of <u>bytes</u> in the value, not the number of characters.)^ 3737** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3738** is negative, then the length of the string is 3739** the number of bytes up to the first zero terminator. 3740** If the fourth parameter to sqlite3_bind_blob() is negative, then 3741** the behavior is undefined. 3742** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3743** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3744** that parameter must be the byte offset 3745** where the NUL terminator would occur assuming the string were NUL 3746** terminated. If any NUL characters occur at byte offsets less than 3747** the value of the fourth parameter then the resulting string value will 3748** contain embedded NULs. The result of expressions involving strings 3749** with embedded NULs is undefined. 3750** 3751** ^The fifth argument to the BLOB and string binding interfaces 3752** is a destructor used to dispose of the BLOB or 3753** string after SQLite has finished with it. ^The destructor is called 3754** to dispose of the BLOB or string even if the call to bind API fails. 3755** ^If the fifth argument is 3756** the special value [SQLITE_STATIC], then SQLite assumes that the 3757** information is in static, unmanaged space and does not need to be freed. 3758** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3759** SQLite makes its own private copy of the data immediately, before 3760** the sqlite3_bind_*() routine returns. 3761** 3762** ^The sixth argument to sqlite3_bind_text64() must be one of 3763** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3764** to specify the encoding of the text in the third parameter. If 3765** the sixth argument to sqlite3_bind_text64() is not one of the 3766** allowed values shown above, or if the text encoding is different 3767** from the encoding specified by the sixth parameter, then the behavior 3768** is undefined. 3769** 3770** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3771** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3772** (just an integer to hold its size) while it is being processed. 3773** Zeroblobs are intended to serve as placeholders for BLOBs whose 3774** content is later written using 3775** [sqlite3_blob_open | incremental BLOB I/O] routines. 3776** ^A negative value for the zeroblob results in a zero-length BLOB. 3777** 3778** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3779** for the [prepared statement] or with a prepared statement for which 3780** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3781** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3782** routine is passed a [prepared statement] that has been finalized, the 3783** result is undefined and probably harmful. 3784** 3785** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3786** ^Unbound parameters are interpreted as NULL. 3787** 3788** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3789** [error code] if anything goes wrong. 3790** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3791** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3792** [SQLITE_MAX_LENGTH]. 3793** ^[SQLITE_RANGE] is returned if the parameter 3794** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3795** 3796** See also: [sqlite3_bind_parameter_count()], 3797** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3798*/ 3799int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3800int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3801 void(*)(void*)); 3802int sqlite3_bind_double(sqlite3_stmt*, int, double); 3803int sqlite3_bind_int(sqlite3_stmt*, int, int); 3804int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3805int sqlite3_bind_null(sqlite3_stmt*, int); 3806int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3807int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3808int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3809 void(*)(void*), unsigned char encoding); 3810int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3811int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3812int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 3813 3814/* 3815** CAPI3REF: Number Of SQL Parameters 3816** METHOD: sqlite3_stmt 3817** 3818** ^This routine can be used to find the number of [SQL parameters] 3819** in a [prepared statement]. SQL parameters are tokens of the 3820** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3821** placeholders for values that are [sqlite3_bind_blob | bound] 3822** to the parameters at a later time. 3823** 3824** ^(This routine actually returns the index of the largest (rightmost) 3825** parameter. For all forms except ?NNN, this will correspond to the 3826** number of unique parameters. If parameters of the ?NNN form are used, 3827** there may be gaps in the list.)^ 3828** 3829** See also: [sqlite3_bind_blob|sqlite3_bind()], 3830** [sqlite3_bind_parameter_name()], and 3831** [sqlite3_bind_parameter_index()]. 3832*/ 3833int sqlite3_bind_parameter_count(sqlite3_stmt*); 3834 3835/* 3836** CAPI3REF: Name Of A Host Parameter 3837** METHOD: sqlite3_stmt 3838** 3839** ^The sqlite3_bind_parameter_name(P,N) interface returns 3840** the name of the N-th [SQL parameter] in the [prepared statement] P. 3841** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3842** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3843** respectively. 3844** In other words, the initial ":" or "$" or "@" or "?" 3845** is included as part of the name.)^ 3846** ^Parameters of the form "?" without a following integer have no name 3847** and are referred to as "nameless" or "anonymous parameters". 3848** 3849** ^The first host parameter has an index of 1, not 0. 3850** 3851** ^If the value N is out of range or if the N-th parameter is 3852** nameless, then NULL is returned. ^The returned string is 3853** always in UTF-8 encoding even if the named parameter was 3854** originally specified as UTF-16 in [sqlite3_prepare16()] or 3855** [sqlite3_prepare16_v2()]. 3856** 3857** See also: [sqlite3_bind_blob|sqlite3_bind()], 3858** [sqlite3_bind_parameter_count()], and 3859** [sqlite3_bind_parameter_index()]. 3860*/ 3861const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3862 3863/* 3864** CAPI3REF: Index Of A Parameter With A Given Name 3865** METHOD: sqlite3_stmt 3866** 3867** ^Return the index of an SQL parameter given its name. ^The 3868** index value returned is suitable for use as the second 3869** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3870** is returned if no matching parameter is found. ^The parameter 3871** name must be given in UTF-8 even if the original statement 3872** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3873** 3874** See also: [sqlite3_bind_blob|sqlite3_bind()], 3875** [sqlite3_bind_parameter_count()], and 3876** [sqlite3_bind_parameter_name()]. 3877*/ 3878int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3879 3880/* 3881** CAPI3REF: Reset All Bindings On A Prepared Statement 3882** METHOD: sqlite3_stmt 3883** 3884** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3885** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3886** ^Use this routine to reset all host parameters to NULL. 3887*/ 3888int sqlite3_clear_bindings(sqlite3_stmt*); 3889 3890/* 3891** CAPI3REF: Number Of Columns In A Result Set 3892** METHOD: sqlite3_stmt 3893** 3894** ^Return the number of columns in the result set returned by the 3895** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3896** statement that does not return data (for example an [UPDATE]). 3897** 3898** See also: [sqlite3_data_count()] 3899*/ 3900int sqlite3_column_count(sqlite3_stmt *pStmt); 3901 3902/* 3903** CAPI3REF: Column Names In A Result Set 3904** METHOD: sqlite3_stmt 3905** 3906** ^These routines return the name assigned to a particular column 3907** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3908** interface returns a pointer to a zero-terminated UTF-8 string 3909** and sqlite3_column_name16() returns a pointer to a zero-terminated 3910** UTF-16 string. ^The first parameter is the [prepared statement] 3911** that implements the [SELECT] statement. ^The second parameter is the 3912** column number. ^The leftmost column is number 0. 3913** 3914** ^The returned string pointer is valid until either the [prepared statement] 3915** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3916** reprepared by the first call to [sqlite3_step()] for a particular run 3917** or until the next call to 3918** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3919** 3920** ^If sqlite3_malloc() fails during the processing of either routine 3921** (for example during a conversion from UTF-8 to UTF-16) then a 3922** NULL pointer is returned. 3923** 3924** ^The name of a result column is the value of the "AS" clause for 3925** that column, if there is an AS clause. If there is no AS clause 3926** then the name of the column is unspecified and may change from 3927** one release of SQLite to the next. 3928*/ 3929const char *sqlite3_column_name(sqlite3_stmt*, int N); 3930const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3931 3932/* 3933** CAPI3REF: Source Of Data In A Query Result 3934** METHOD: sqlite3_stmt 3935** 3936** ^These routines provide a means to determine the database, table, and 3937** table column that is the origin of a particular result column in 3938** [SELECT] statement. 3939** ^The name of the database or table or column can be returned as 3940** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3941** the database name, the _table_ routines return the table name, and 3942** the origin_ routines return the column name. 3943** ^The returned string is valid until the [prepared statement] is destroyed 3944** using [sqlite3_finalize()] or until the statement is automatically 3945** reprepared by the first call to [sqlite3_step()] for a particular run 3946** or until the same information is requested 3947** again in a different encoding. 3948** 3949** ^The names returned are the original un-aliased names of the 3950** database, table, and column. 3951** 3952** ^The first argument to these interfaces is a [prepared statement]. 3953** ^These functions return information about the Nth result column returned by 3954** the statement, where N is the second function argument. 3955** ^The left-most column is column 0 for these routines. 3956** 3957** ^If the Nth column returned by the statement is an expression or 3958** subquery and is not a column value, then all of these functions return 3959** NULL. ^These routine might also return NULL if a memory allocation error 3960** occurs. ^Otherwise, they return the name of the attached database, table, 3961** or column that query result column was extracted from. 3962** 3963** ^As with all other SQLite APIs, those whose names end with "16" return 3964** UTF-16 encoded strings and the other functions return UTF-8. 3965** 3966** ^These APIs are only available if the library was compiled with the 3967** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3968** 3969** If two or more threads call one or more of these routines against the same 3970** prepared statement and column at the same time then the results are 3971** undefined. 3972** 3973** If two or more threads call one or more 3974** [sqlite3_column_database_name | column metadata interfaces] 3975** for the same [prepared statement] and result column 3976** at the same time then the results are undefined. 3977*/ 3978const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3979const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3980const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3981const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3982const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3983const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3984 3985/* 3986** CAPI3REF: Declared Datatype Of A Query Result 3987** METHOD: sqlite3_stmt 3988** 3989** ^(The first parameter is a [prepared statement]. 3990** If this statement is a [SELECT] statement and the Nth column of the 3991** returned result set of that [SELECT] is a table column (not an 3992** expression or subquery) then the declared type of the table 3993** column is returned.)^ ^If the Nth column of the result set is an 3994** expression or subquery, then a NULL pointer is returned. 3995** ^The returned string is always UTF-8 encoded. 3996** 3997** ^(For example, given the database schema: 3998** 3999** CREATE TABLE t1(c1 VARIANT); 4000** 4001** and the following statement to be compiled: 4002** 4003** SELECT c1 + 1, c1 FROM t1; 4004** 4005** this routine would return the string "VARIANT" for the second result 4006** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4007** 4008** ^SQLite uses dynamic run-time typing. ^So just because a column 4009** is declared to contain a particular type does not mean that the 4010** data stored in that column is of the declared type. SQLite is 4011** strongly typed, but the typing is dynamic not static. ^Type 4012** is associated with individual values, not with the containers 4013** used to hold those values. 4014*/ 4015const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4016const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4017 4018/* 4019** CAPI3REF: Evaluate An SQL Statement 4020** METHOD: sqlite3_stmt 4021** 4022** After a [prepared statement] has been prepared using either 4023** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 4024** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4025** must be called one or more times to evaluate the statement. 4026** 4027** The details of the behavior of the sqlite3_step() interface depend 4028** on whether the statement was prepared using the newer "v2" interface 4029** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 4030** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4031** new "v2" interface is recommended for new applications but the legacy 4032** interface will continue to be supported. 4033** 4034** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4035** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4036** ^With the "v2" interface, any of the other [result codes] or 4037** [extended result codes] might be returned as well. 4038** 4039** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4040** database locks it needs to do its job. ^If the statement is a [COMMIT] 4041** or occurs outside of an explicit transaction, then you can retry the 4042** statement. If the statement is not a [COMMIT] and occurs within an 4043** explicit transaction then you should rollback the transaction before 4044** continuing. 4045** 4046** ^[SQLITE_DONE] means that the statement has finished executing 4047** successfully. sqlite3_step() should not be called again on this virtual 4048** machine without first calling [sqlite3_reset()] to reset the virtual 4049** machine back to its initial state. 4050** 4051** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4052** is returned each time a new row of data is ready for processing by the 4053** caller. The values may be accessed using the [column access functions]. 4054** sqlite3_step() is called again to retrieve the next row of data. 4055** 4056** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4057** violation) has occurred. sqlite3_step() should not be called again on 4058** the VM. More information may be found by calling [sqlite3_errmsg()]. 4059** ^With the legacy interface, a more specific error code (for example, 4060** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4061** can be obtained by calling [sqlite3_reset()] on the 4062** [prepared statement]. ^In the "v2" interface, 4063** the more specific error code is returned directly by sqlite3_step(). 4064** 4065** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4066** Perhaps it was called on a [prepared statement] that has 4067** already been [sqlite3_finalize | finalized] or on one that had 4068** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4069** be the case that the same database connection is being used by two or 4070** more threads at the same moment in time. 4071** 4072** For all versions of SQLite up to and including 3.6.23.1, a call to 4073** [sqlite3_reset()] was required after sqlite3_step() returned anything 4074** other than [SQLITE_ROW] before any subsequent invocation of 4075** sqlite3_step(). Failure to reset the prepared statement using 4076** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4077** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4078** sqlite3_step() began 4079** calling [sqlite3_reset()] automatically in this circumstance rather 4080** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4081** break because any application that ever receives an SQLITE_MISUSE error 4082** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4083** can be used to restore the legacy behavior. 4084** 4085** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4086** API always returns a generic error code, [SQLITE_ERROR], following any 4087** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4088** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4089** specific [error codes] that better describes the error. 4090** We admit that this is a goofy design. The problem has been fixed 4091** with the "v2" interface. If you prepare all of your SQL statements 4092** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 4093** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4094** then the more specific [error codes] are returned directly 4095** by sqlite3_step(). The use of the "v2" interface is recommended. 4096*/ 4097int sqlite3_step(sqlite3_stmt*); 4098 4099/* 4100** CAPI3REF: Number of columns in a result set 4101** METHOD: sqlite3_stmt 4102** 4103** ^The sqlite3_data_count(P) interface returns the number of columns in the 4104** current row of the result set of [prepared statement] P. 4105** ^If prepared statement P does not have results ready to return 4106** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 4107** interfaces) then sqlite3_data_count(P) returns 0. 4108** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4109** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4110** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4111** will return non-zero if previous call to [sqlite3_step](P) returned 4112** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4113** where it always returns zero since each step of that multi-step 4114** pragma returns 0 columns of data. 4115** 4116** See also: [sqlite3_column_count()] 4117*/ 4118int sqlite3_data_count(sqlite3_stmt *pStmt); 4119 4120/* 4121** CAPI3REF: Fundamental Datatypes 4122** KEYWORDS: SQLITE_TEXT 4123** 4124** ^(Every value in SQLite has one of five fundamental datatypes: 4125** 4126** <ul> 4127** <li> 64-bit signed integer 4128** <li> 64-bit IEEE floating point number 4129** <li> string 4130** <li> BLOB 4131** <li> NULL 4132** </ul>)^ 4133** 4134** These constants are codes for each of those types. 4135** 4136** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4137** for a completely different meaning. Software that links against both 4138** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4139** SQLITE_TEXT. 4140*/ 4141#define SQLITE_INTEGER 1 4142#define SQLITE_FLOAT 2 4143#define SQLITE_BLOB 4 4144#define SQLITE_NULL 5 4145#ifdef SQLITE_TEXT 4146# undef SQLITE_TEXT 4147#else 4148# define SQLITE_TEXT 3 4149#endif 4150#define SQLITE3_TEXT 3 4151 4152/* 4153** CAPI3REF: Result Values From A Query 4154** KEYWORDS: {column access functions} 4155** METHOD: sqlite3_stmt 4156** 4157** ^These routines return information about a single column of the current 4158** result row of a query. ^In every case the first argument is a pointer 4159** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4160** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4161** and the second argument is the index of the column for which information 4162** should be returned. ^The leftmost column of the result set has the index 0. 4163** ^The number of columns in the result can be determined using 4164** [sqlite3_column_count()]. 4165** 4166** If the SQL statement does not currently point to a valid row, or if the 4167** column index is out of range, the result is undefined. 4168** These routines may only be called when the most recent call to 4169** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4170** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4171** If any of these routines are called after [sqlite3_reset()] or 4172** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4173** something other than [SQLITE_ROW], the results are undefined. 4174** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4175** are called from a different thread while any of these routines 4176** are pending, then the results are undefined. 4177** 4178** ^The sqlite3_column_type() routine returns the 4179** [SQLITE_INTEGER | datatype code] for the initial data type 4180** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4181** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 4182** returned by sqlite3_column_type() is only meaningful if no type 4183** conversions have occurred as described below. After a type conversion, 4184** the value returned by sqlite3_column_type() is undefined. Future 4185** versions of SQLite may change the behavior of sqlite3_column_type() 4186** following a type conversion. 4187** 4188** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4189** routine returns the number of bytes in that BLOB or string. 4190** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4191** the string to UTF-8 and then returns the number of bytes. 4192** ^If the result is a numeric value then sqlite3_column_bytes() uses 4193** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4194** the number of bytes in that string. 4195** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4196** 4197** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4198** routine returns the number of bytes in that BLOB or string. 4199** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4200** the string to UTF-16 and then returns the number of bytes. 4201** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4202** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4203** the number of bytes in that string. 4204** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4205** 4206** ^The values returned by [sqlite3_column_bytes()] and 4207** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4208** of the string. ^For clarity: the values returned by 4209** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4210** bytes in the string, not the number of characters. 4211** 4212** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4213** even empty strings, are always zero-terminated. ^The return 4214** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4215** 4216** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4217** [unprotected sqlite3_value] object. In a multithreaded environment, 4218** an unprotected sqlite3_value object may only be used safely with 4219** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4220** If the [unprotected sqlite3_value] object returned by 4221** [sqlite3_column_value()] is used in any other way, including calls 4222** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4223** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4224** 4225** These routines attempt to convert the value where appropriate. ^For 4226** example, if the internal representation is FLOAT and a text result 4227** is requested, [sqlite3_snprintf()] is used internally to perform the 4228** conversion automatically. ^(The following table details the conversions 4229** that are applied: 4230** 4231** <blockquote> 4232** <table border="1"> 4233** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4234** 4235** <tr><td> NULL <td> INTEGER <td> Result is 0 4236** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4237** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4238** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4239** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4240** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4241** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4242** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4243** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4244** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4245** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4246** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4247** <tr><td> TEXT <td> BLOB <td> No change 4248** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4249** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4250** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4251** </table> 4252** </blockquote>)^ 4253** 4254** Note that when type conversions occur, pointers returned by prior 4255** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4256** sqlite3_column_text16() may be invalidated. 4257** Type conversions and pointer invalidations might occur 4258** in the following cases: 4259** 4260** <ul> 4261** <li> The initial content is a BLOB and sqlite3_column_text() or 4262** sqlite3_column_text16() is called. A zero-terminator might 4263** need to be added to the string.</li> 4264** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4265** sqlite3_column_text16() is called. The content must be converted 4266** to UTF-16.</li> 4267** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4268** sqlite3_column_text() is called. The content must be converted 4269** to UTF-8.</li> 4270** </ul> 4271** 4272** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4273** not invalidate a prior pointer, though of course the content of the buffer 4274** that the prior pointer references will have been modified. Other kinds 4275** of conversion are done in place when it is possible, but sometimes they 4276** are not possible and in those cases prior pointers are invalidated. 4277** 4278** The safest policy is to invoke these routines 4279** in one of the following ways: 4280** 4281** <ul> 4282** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4283** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4284** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4285** </ul> 4286** 4287** In other words, you should call sqlite3_column_text(), 4288** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4289** into the desired format, then invoke sqlite3_column_bytes() or 4290** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4291** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4292** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4293** with calls to sqlite3_column_bytes(). 4294** 4295** ^The pointers returned are valid until a type conversion occurs as 4296** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4297** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4298** and BLOBs is freed automatically. Do <em>not</em> pass the pointers returned 4299** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4300** [sqlite3_free()]. 4301** 4302** ^(If a memory allocation error occurs during the evaluation of any 4303** of these routines, a default value is returned. The default value 4304** is either the integer 0, the floating point number 0.0, or a NULL 4305** pointer. Subsequent calls to [sqlite3_errcode()] will return 4306** [SQLITE_NOMEM].)^ 4307*/ 4308const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4309int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4310int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4311double sqlite3_column_double(sqlite3_stmt*, int iCol); 4312int sqlite3_column_int(sqlite3_stmt*, int iCol); 4313sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4314const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4315const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4316int sqlite3_column_type(sqlite3_stmt*, int iCol); 4317sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4318 4319/* 4320** CAPI3REF: Destroy A Prepared Statement Object 4321** DESTRUCTOR: sqlite3_stmt 4322** 4323** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4324** ^If the most recent evaluation of the statement encountered no errors 4325** or if the statement is never been evaluated, then sqlite3_finalize() returns 4326** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4327** sqlite3_finalize(S) returns the appropriate [error code] or 4328** [extended error code]. 4329** 4330** ^The sqlite3_finalize(S) routine can be called at any point during 4331** the life cycle of [prepared statement] S: 4332** before statement S is ever evaluated, after 4333** one or more calls to [sqlite3_reset()], or after any call 4334** to [sqlite3_step()] regardless of whether or not the statement has 4335** completed execution. 4336** 4337** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4338** 4339** The application must finalize every [prepared statement] in order to avoid 4340** resource leaks. It is a grievous error for the application to try to use 4341** a prepared statement after it has been finalized. Any use of a prepared 4342** statement after it has been finalized can result in undefined and 4343** undesirable behavior such as segfaults and heap corruption. 4344*/ 4345int sqlite3_finalize(sqlite3_stmt *pStmt); 4346 4347/* 4348** CAPI3REF: Reset A Prepared Statement Object 4349** METHOD: sqlite3_stmt 4350** 4351** The sqlite3_reset() function is called to reset a [prepared statement] 4352** object back to its initial state, ready to be re-executed. 4353** ^Any SQL statement variables that had values bound to them using 4354** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4355** Use [sqlite3_clear_bindings()] to reset the bindings. 4356** 4357** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4358** back to the beginning of its program. 4359** 4360** ^If the most recent call to [sqlite3_step(S)] for the 4361** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4362** or if [sqlite3_step(S)] has never before been called on S, 4363** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4364** 4365** ^If the most recent call to [sqlite3_step(S)] for the 4366** [prepared statement] S indicated an error, then 4367** [sqlite3_reset(S)] returns an appropriate [error code]. 4368** 4369** ^The [sqlite3_reset(S)] interface does not change the values 4370** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4371*/ 4372int sqlite3_reset(sqlite3_stmt *pStmt); 4373 4374/* 4375** CAPI3REF: Create Or Redefine SQL Functions 4376** KEYWORDS: {function creation routines} 4377** KEYWORDS: {application-defined SQL function} 4378** KEYWORDS: {application-defined SQL functions} 4379** METHOD: sqlite3 4380** 4381** ^These functions (collectively known as "function creation routines") 4382** are used to add SQL functions or aggregates or to redefine the behavior 4383** of existing SQL functions or aggregates. The only differences between 4384** these routines are the text encoding expected for 4385** the second parameter (the name of the function being created) 4386** and the presence or absence of a destructor callback for 4387** the application data pointer. 4388** 4389** ^The first parameter is the [database connection] to which the SQL 4390** function is to be added. ^If an application uses more than one database 4391** connection then application-defined SQL functions must be added 4392** to each database connection separately. 4393** 4394** ^The second parameter is the name of the SQL function to be created or 4395** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4396** representation, exclusive of the zero-terminator. ^Note that the name 4397** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4398** ^Any attempt to create a function with a longer name 4399** will result in [SQLITE_MISUSE] being returned. 4400** 4401** ^The third parameter (nArg) 4402** is the number of arguments that the SQL function or 4403** aggregate takes. ^If this parameter is -1, then the SQL function or 4404** aggregate may take any number of arguments between 0 and the limit 4405** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4406** parameter is less than -1 or greater than 127 then the behavior is 4407** undefined. 4408** 4409** ^The fourth parameter, eTextRep, specifies what 4410** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4411** its parameters. The application should set this parameter to 4412** [SQLITE_UTF16LE] if the function implementation invokes 4413** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4414** implementation invokes [sqlite3_value_text16be()] on an input, or 4415** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4416** otherwise. ^The same SQL function may be registered multiple times using 4417** different preferred text encodings, with different implementations for 4418** each encoding. 4419** ^When multiple implementations of the same function are available, SQLite 4420** will pick the one that involves the least amount of data conversion. 4421** 4422** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4423** to signal that the function will always return the same result given 4424** the same inputs within a single SQL statement. Most SQL functions are 4425** deterministic. The built-in [random()] SQL function is an example of a 4426** function that is not deterministic. The SQLite query planner is able to 4427** perform additional optimizations on deterministic functions, so use 4428** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4429** 4430** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4431** function can gain access to this pointer using [sqlite3_user_data()].)^ 4432** 4433** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4434** pointers to C-language functions that implement the SQL function or 4435** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4436** callback only; NULL pointers must be passed as the xStep and xFinal 4437** parameters. ^An aggregate SQL function requires an implementation of xStep 4438** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4439** SQL function or aggregate, pass NULL pointers for all three function 4440** callbacks. 4441** 4442** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4443** then it is destructor for the application data pointer. 4444** The destructor is invoked when the function is deleted, either by being 4445** overloaded or when the database connection closes.)^ 4446** ^The destructor is also invoked if the call to 4447** sqlite3_create_function_v2() fails. 4448** ^When the destructor callback of the tenth parameter is invoked, it 4449** is passed a single argument which is a copy of the application data 4450** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4451** 4452** ^It is permitted to register multiple implementations of the same 4453** functions with the same name but with either differing numbers of 4454** arguments or differing preferred text encodings. ^SQLite will use 4455** the implementation that most closely matches the way in which the 4456** SQL function is used. ^A function implementation with a non-negative 4457** nArg parameter is a better match than a function implementation with 4458** a negative nArg. ^A function where the preferred text encoding 4459** matches the database encoding is a better 4460** match than a function where the encoding is different. 4461** ^A function where the encoding difference is between UTF16le and UTF16be 4462** is a closer match than a function where the encoding difference is 4463** between UTF8 and UTF16. 4464** 4465** ^Built-in functions may be overloaded by new application-defined functions. 4466** 4467** ^An application-defined function is permitted to call other 4468** SQLite interfaces. However, such calls must not 4469** close the database connection nor finalize or reset the prepared 4470** statement in which the function is running. 4471*/ 4472int sqlite3_create_function( 4473 sqlite3 *db, 4474 const char *zFunctionName, 4475 int nArg, 4476 int eTextRep, 4477 void *pApp, 4478 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4479 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4480 void (*xFinal)(sqlite3_context*) 4481); 4482int sqlite3_create_function16( 4483 sqlite3 *db, 4484 const void *zFunctionName, 4485 int nArg, 4486 int eTextRep, 4487 void *pApp, 4488 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4489 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4490 void (*xFinal)(sqlite3_context*) 4491); 4492int sqlite3_create_function_v2( 4493 sqlite3 *db, 4494 const char *zFunctionName, 4495 int nArg, 4496 int eTextRep, 4497 void *pApp, 4498 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4499 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4500 void (*xFinal)(sqlite3_context*), 4501 void(*xDestroy)(void*) 4502); 4503 4504/* 4505** CAPI3REF: Text Encodings 4506** 4507** These constant define integer codes that represent the various 4508** text encodings supported by SQLite. 4509*/ 4510#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4511#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4512#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4513#define SQLITE_UTF16 4 /* Use native byte order */ 4514#define SQLITE_ANY 5 /* Deprecated */ 4515#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4516 4517/* 4518** CAPI3REF: Function Flags 4519** 4520** These constants may be ORed together with the 4521** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4522** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4523** [sqlite3_create_function_v2()]. 4524*/ 4525#define SQLITE_DETERMINISTIC 0x800 4526 4527/* 4528** CAPI3REF: Deprecated Functions 4529** DEPRECATED 4530** 4531** These functions are [deprecated]. In order to maintain 4532** backwards compatibility with older code, these functions continue 4533** to be supported. However, new applications should avoid 4534** the use of these functions. To encourage programmers to avoid 4535** these functions, we will not explain what they do. 4536*/ 4537#ifndef SQLITE_OMIT_DEPRECATED 4538SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4539SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4540SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4541SQLITE_DEPRECATED int sqlite3_global_recover(void); 4542SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4543SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4544 void*,sqlite3_int64); 4545#endif 4546 4547/* 4548** CAPI3REF: Obtaining SQL Values 4549** METHOD: sqlite3_value 4550** 4551** The C-language implementation of SQL functions and aggregates uses 4552** this set of interface routines to access the parameter values on 4553** the function or aggregate. 4554** 4555** The xFunc (for scalar functions) or xStep (for aggregates) parameters 4556** to [sqlite3_create_function()] and [sqlite3_create_function16()] 4557** define callbacks that implement the SQL functions and aggregates. 4558** The 3rd parameter to these callbacks is an array of pointers to 4559** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 4560** each parameter to the SQL function. These routines are used to 4561** extract values from the [sqlite3_value] objects. 4562** 4563** These routines work only with [protected sqlite3_value] objects. 4564** Any attempt to use these routines on an [unprotected sqlite3_value] 4565** object results in undefined behavior. 4566** 4567** ^These routines work just like the corresponding [column access functions] 4568** except that these routines take a single [protected sqlite3_value] object 4569** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4570** 4571** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4572** in the native byte-order of the host machine. ^The 4573** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4574** extract UTF-16 strings as big-endian and little-endian respectively. 4575** 4576** ^(The sqlite3_value_numeric_type() interface attempts to apply 4577** numeric affinity to the value. This means that an attempt is 4578** made to convert the value to an integer or floating point. If 4579** such a conversion is possible without loss of information (in other 4580** words, if the value is a string that looks like a number) 4581** then the conversion is performed. Otherwise no conversion occurs. 4582** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4583** 4584** Please pay particular attention to the fact that the pointer returned 4585** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4586** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4587** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4588** or [sqlite3_value_text16()]. 4589** 4590** These routines must be called from the same thread as 4591** the SQL function that supplied the [sqlite3_value*] parameters. 4592*/ 4593const void *sqlite3_value_blob(sqlite3_value*); 4594int sqlite3_value_bytes(sqlite3_value*); 4595int sqlite3_value_bytes16(sqlite3_value*); 4596double sqlite3_value_double(sqlite3_value*); 4597int sqlite3_value_int(sqlite3_value*); 4598sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4599const unsigned char *sqlite3_value_text(sqlite3_value*); 4600const void *sqlite3_value_text16(sqlite3_value*); 4601const void *sqlite3_value_text16le(sqlite3_value*); 4602const void *sqlite3_value_text16be(sqlite3_value*); 4603int sqlite3_value_type(sqlite3_value*); 4604int sqlite3_value_numeric_type(sqlite3_value*); 4605 4606/* 4607** CAPI3REF: Finding The Subtype Of SQL Values 4608** METHOD: sqlite3_value 4609** 4610** The sqlite3_value_subtype(V) function returns the subtype for 4611** an [application-defined SQL function] argument V. The subtype 4612** information can be used to pass a limited amount of context from 4613** one SQL function to another. Use the [sqlite3_result_subtype()] 4614** routine to set the subtype for the return value of an SQL function. 4615** 4616** SQLite makes no use of subtype itself. It merely passes the subtype 4617** from the result of one [application-defined SQL function] into the 4618** input of another. 4619*/ 4620unsigned int sqlite3_value_subtype(sqlite3_value*); 4621 4622/* 4623** CAPI3REF: Copy And Free SQL Values 4624** METHOD: sqlite3_value 4625** 4626** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 4627** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 4628** is a [protected sqlite3_value] object even if the input is not. 4629** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 4630** memory allocation fails. 4631** 4632** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 4633** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 4634** then sqlite3_value_free(V) is a harmless no-op. 4635*/ 4636sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 4637void sqlite3_value_free(sqlite3_value*); 4638 4639/* 4640** CAPI3REF: Obtain Aggregate Function Context 4641** METHOD: sqlite3_context 4642** 4643** Implementations of aggregate SQL functions use this 4644** routine to allocate memory for storing their state. 4645** 4646** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4647** for a particular aggregate function, SQLite 4648** allocates N of memory, zeroes out that memory, and returns a pointer 4649** to the new memory. ^On second and subsequent calls to 4650** sqlite3_aggregate_context() for the same aggregate function instance, 4651** the same buffer is returned. Sqlite3_aggregate_context() is normally 4652** called once for each invocation of the xStep callback and then one 4653** last time when the xFinal callback is invoked. ^(When no rows match 4654** an aggregate query, the xStep() callback of the aggregate function 4655** implementation is never called and xFinal() is called exactly once. 4656** In those cases, sqlite3_aggregate_context() might be called for the 4657** first time from within xFinal().)^ 4658** 4659** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4660** when first called if N is less than or equal to zero or if a memory 4661** allocate error occurs. 4662** 4663** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4664** determined by the N parameter on first successful call. Changing the 4665** value of N in subsequent call to sqlite3_aggregate_context() within 4666** the same aggregate function instance will not resize the memory 4667** allocation.)^ Within the xFinal callback, it is customary to set 4668** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4669** pointless memory allocations occur. 4670** 4671** ^SQLite automatically frees the memory allocated by 4672** sqlite3_aggregate_context() when the aggregate query concludes. 4673** 4674** The first parameter must be a copy of the 4675** [sqlite3_context | SQL function context] that is the first parameter 4676** to the xStep or xFinal callback routine that implements the aggregate 4677** function. 4678** 4679** This routine must be called from the same thread in which 4680** the aggregate SQL function is running. 4681*/ 4682void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4683 4684/* 4685** CAPI3REF: User Data For Functions 4686** METHOD: sqlite3_context 4687** 4688** ^The sqlite3_user_data() interface returns a copy of 4689** the pointer that was the pUserData parameter (the 5th parameter) 4690** of the [sqlite3_create_function()] 4691** and [sqlite3_create_function16()] routines that originally 4692** registered the application defined function. 4693** 4694** This routine must be called from the same thread in which 4695** the application-defined function is running. 4696*/ 4697void *sqlite3_user_data(sqlite3_context*); 4698 4699/* 4700** CAPI3REF: Database Connection For Functions 4701** METHOD: sqlite3_context 4702** 4703** ^The sqlite3_context_db_handle() interface returns a copy of 4704** the pointer to the [database connection] (the 1st parameter) 4705** of the [sqlite3_create_function()] 4706** and [sqlite3_create_function16()] routines that originally 4707** registered the application defined function. 4708*/ 4709sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4710 4711/* 4712** CAPI3REF: Function Auxiliary Data 4713** METHOD: sqlite3_context 4714** 4715** These functions may be used by (non-aggregate) SQL functions to 4716** associate metadata with argument values. If the same value is passed to 4717** multiple invocations of the same SQL function during query execution, under 4718** some circumstances the associated metadata may be preserved. An example 4719** of where this might be useful is in a regular-expression matching 4720** function. The compiled version of the regular expression can be stored as 4721** metadata associated with the pattern string. 4722** Then as long as the pattern string remains the same, 4723** the compiled regular expression can be reused on multiple 4724** invocations of the same function. 4725** 4726** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4727** associated by the sqlite3_set_auxdata() function with the Nth argument 4728** value to the application-defined function. ^If there is no metadata 4729** associated with the function argument, this sqlite3_get_auxdata() interface 4730** returns a NULL pointer. 4731** 4732** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4733** argument of the application-defined function. ^Subsequent 4734** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4735** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4736** NULL if the metadata has been discarded. 4737** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4738** SQLite will invoke the destructor function X with parameter P exactly 4739** once, when the metadata is discarded. 4740** SQLite is free to discard the metadata at any time, including: <ul> 4741** <li> ^(when the corresponding function parameter changes)^, or 4742** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4743** SQL statement)^, or 4744** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 4745** parameter)^, or 4746** <li> ^(during the original sqlite3_set_auxdata() call when a memory 4747** allocation error occurs.)^ </ul> 4748** 4749** Note the last bullet in particular. The destructor X in 4750** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 4751** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 4752** should be called near the end of the function implementation and the 4753** function implementation should not make any use of P after 4754** sqlite3_set_auxdata() has been called. 4755** 4756** ^(In practice, metadata is preserved between function calls for 4757** function parameters that are compile-time constants, including literal 4758** values and [parameters] and expressions composed from the same.)^ 4759** 4760** These routines must be called from the same thread in which 4761** the SQL function is running. 4762*/ 4763void *sqlite3_get_auxdata(sqlite3_context*, int N); 4764void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4765 4766 4767/* 4768** CAPI3REF: Constants Defining Special Destructor Behavior 4769** 4770** These are special values for the destructor that is passed in as the 4771** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4772** argument is SQLITE_STATIC, it means that the content pointer is constant 4773** and will never change. It does not need to be destroyed. ^The 4774** SQLITE_TRANSIENT value means that the content will likely change in 4775** the near future and that SQLite should make its own private copy of 4776** the content before returning. 4777** 4778** The typedef is necessary to work around problems in certain 4779** C++ compilers. 4780*/ 4781typedef void (*sqlite3_destructor_type)(void*); 4782#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4783#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4784 4785/* 4786** CAPI3REF: Setting The Result Of An SQL Function 4787** METHOD: sqlite3_context 4788** 4789** These routines are used by the xFunc or xFinal callbacks that 4790** implement SQL functions and aggregates. See 4791** [sqlite3_create_function()] and [sqlite3_create_function16()] 4792** for additional information. 4793** 4794** These functions work very much like the [parameter binding] family of 4795** functions used to bind values to host parameters in prepared statements. 4796** Refer to the [SQL parameter] documentation for additional information. 4797** 4798** ^The sqlite3_result_blob() interface sets the result from 4799** an application-defined function to be the BLOB whose content is pointed 4800** to by the second parameter and which is N bytes long where N is the 4801** third parameter. 4802** 4803** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 4804** interfaces set the result of the application-defined function to be 4805** a BLOB containing all zero bytes and N bytes in size. 4806** 4807** ^The sqlite3_result_double() interface sets the result from 4808** an application-defined function to be a floating point value specified 4809** by its 2nd argument. 4810** 4811** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4812** cause the implemented SQL function to throw an exception. 4813** ^SQLite uses the string pointed to by the 4814** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4815** as the text of an error message. ^SQLite interprets the error 4816** message string from sqlite3_result_error() as UTF-8. ^SQLite 4817** interprets the string from sqlite3_result_error16() as UTF-16 in native 4818** byte order. ^If the third parameter to sqlite3_result_error() 4819** or sqlite3_result_error16() is negative then SQLite takes as the error 4820** message all text up through the first zero character. 4821** ^If the third parameter to sqlite3_result_error() or 4822** sqlite3_result_error16() is non-negative then SQLite takes that many 4823** bytes (not characters) from the 2nd parameter as the error message. 4824** ^The sqlite3_result_error() and sqlite3_result_error16() 4825** routines make a private copy of the error message text before 4826** they return. Hence, the calling function can deallocate or 4827** modify the text after they return without harm. 4828** ^The sqlite3_result_error_code() function changes the error code 4829** returned by SQLite as a result of an error in a function. ^By default, 4830** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4831** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4832** 4833** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 4834** error indicating that a string or BLOB is too long to represent. 4835** 4836** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 4837** error indicating that a memory allocation failed. 4838** 4839** ^The sqlite3_result_int() interface sets the return value 4840** of the application-defined function to be the 32-bit signed integer 4841** value given in the 2nd argument. 4842** ^The sqlite3_result_int64() interface sets the return value 4843** of the application-defined function to be the 64-bit signed integer 4844** value given in the 2nd argument. 4845** 4846** ^The sqlite3_result_null() interface sets the return value 4847** of the application-defined function to be NULL. 4848** 4849** ^The sqlite3_result_text(), sqlite3_result_text16(), 4850** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4851** set the return value of the application-defined function to be 4852** a text string which is represented as UTF-8, UTF-16 native byte order, 4853** UTF-16 little endian, or UTF-16 big endian, respectively. 4854** ^The sqlite3_result_text64() interface sets the return value of an 4855** application-defined function to be a text string in an encoding 4856** specified by the fifth (and last) parameter, which must be one 4857** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 4858** ^SQLite takes the text result from the application from 4859** the 2nd parameter of the sqlite3_result_text* interfaces. 4860** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4861** is negative, then SQLite takes result text from the 2nd parameter 4862** through the first zero character. 4863** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4864** is non-negative, then as many bytes (not characters) of the text 4865** pointed to by the 2nd parameter are taken as the application-defined 4866** function result. If the 3rd parameter is non-negative, then it 4867** must be the byte offset into the string where the NUL terminator would 4868** appear if the string where NUL terminated. If any NUL characters occur 4869** in the string at a byte offset that is less than the value of the 3rd 4870** parameter, then the resulting string will contain embedded NULs and the 4871** result of expressions operating on strings with embedded NULs is undefined. 4872** ^If the 4th parameter to the sqlite3_result_text* interfaces 4873** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4874** function as the destructor on the text or BLOB result when it has 4875** finished using that result. 4876** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4877** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4878** assumes that the text or BLOB result is in constant space and does not 4879** copy the content of the parameter nor call a destructor on the content 4880** when it has finished using that result. 4881** ^If the 4th parameter to the sqlite3_result_text* interfaces 4882** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4883** then SQLite makes a copy of the result into space obtained from 4884** from [sqlite3_malloc()] before it returns. 4885** 4886** ^The sqlite3_result_value() interface sets the result of 4887** the application-defined function to be a copy of the 4888** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4889** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4890** so that the [sqlite3_value] specified in the parameter may change or 4891** be deallocated after sqlite3_result_value() returns without harm. 4892** ^A [protected sqlite3_value] object may always be used where an 4893** [unprotected sqlite3_value] object is required, so either 4894** kind of [sqlite3_value] object can be used with this interface. 4895** 4896** If these routines are called from within the different thread 4897** than the one containing the application-defined function that received 4898** the [sqlite3_context] pointer, the results are undefined. 4899*/ 4900void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4901void sqlite3_result_blob64(sqlite3_context*,const void*, 4902 sqlite3_uint64,void(*)(void*)); 4903void sqlite3_result_double(sqlite3_context*, double); 4904void sqlite3_result_error(sqlite3_context*, const char*, int); 4905void sqlite3_result_error16(sqlite3_context*, const void*, int); 4906void sqlite3_result_error_toobig(sqlite3_context*); 4907void sqlite3_result_error_nomem(sqlite3_context*); 4908void sqlite3_result_error_code(sqlite3_context*, int); 4909void sqlite3_result_int(sqlite3_context*, int); 4910void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4911void sqlite3_result_null(sqlite3_context*); 4912void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4913void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 4914 void(*)(void*), unsigned char encoding); 4915void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4916void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4917void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4918void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4919void sqlite3_result_zeroblob(sqlite3_context*, int n); 4920int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 4921 4922 4923/* 4924** CAPI3REF: Setting The Subtype Of An SQL Function 4925** METHOD: sqlite3_context 4926** 4927** The sqlite3_result_subtype(C,T) function causes the subtype of 4928** the result from the [application-defined SQL function] with 4929** [sqlite3_context] C to be the value T. Only the lower 8 bits 4930** of the subtype T are preserved in current versions of SQLite; 4931** higher order bits are discarded. 4932** The number of subtype bytes preserved by SQLite might increase 4933** in future releases of SQLite. 4934*/ 4935void sqlite3_result_subtype(sqlite3_context*,unsigned int); 4936 4937/* 4938** CAPI3REF: Define New Collating Sequences 4939** METHOD: sqlite3 4940** 4941** ^These functions add, remove, or modify a [collation] associated 4942** with the [database connection] specified as the first argument. 4943** 4944** ^The name of the collation is a UTF-8 string 4945** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4946** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4947** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4948** considered to be the same name. 4949** 4950** ^(The third argument (eTextRep) must be one of the constants: 4951** <ul> 4952** <li> [SQLITE_UTF8], 4953** <li> [SQLITE_UTF16LE], 4954** <li> [SQLITE_UTF16BE], 4955** <li> [SQLITE_UTF16], or 4956** <li> [SQLITE_UTF16_ALIGNED]. 4957** </ul>)^ 4958** ^The eTextRep argument determines the encoding of strings passed 4959** to the collating function callback, xCallback. 4960** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4961** force strings to be UTF16 with native byte order. 4962** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4963** on an even byte address. 4964** 4965** ^The fourth argument, pArg, is an application data pointer that is passed 4966** through as the first argument to the collating function callback. 4967** 4968** ^The fifth argument, xCallback, is a pointer to the collating function. 4969** ^Multiple collating functions can be registered using the same name but 4970** with different eTextRep parameters and SQLite will use whichever 4971** function requires the least amount of data transformation. 4972** ^If the xCallback argument is NULL then the collating function is 4973** deleted. ^When all collating functions having the same name are deleted, 4974** that collation is no longer usable. 4975** 4976** ^The collating function callback is invoked with a copy of the pArg 4977** application data pointer and with two strings in the encoding specified 4978** by the eTextRep argument. The collating function must return an 4979** integer that is negative, zero, or positive 4980** if the first string is less than, equal to, or greater than the second, 4981** respectively. A collating function must always return the same answer 4982** given the same inputs. If two or more collating functions are registered 4983** to the same collation name (using different eTextRep values) then all 4984** must give an equivalent answer when invoked with equivalent strings. 4985** The collating function must obey the following properties for all 4986** strings A, B, and C: 4987** 4988** <ol> 4989** <li> If A==B then B==A. 4990** <li> If A==B and B==C then A==C. 4991** <li> If A<B THEN B>A. 4992** <li> If A<B and B<C then A<C. 4993** </ol> 4994** 4995** If a collating function fails any of the above constraints and that 4996** collating function is registered and used, then the behavior of SQLite 4997** is undefined. 4998** 4999** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5000** with the addition that the xDestroy callback is invoked on pArg when 5001** the collating function is deleted. 5002** ^Collating functions are deleted when they are overridden by later 5003** calls to the collation creation functions or when the 5004** [database connection] is closed using [sqlite3_close()]. 5005** 5006** ^The xDestroy callback is <u>not</u> called if the 5007** sqlite3_create_collation_v2() function fails. Applications that invoke 5008** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5009** check the return code and dispose of the application data pointer 5010** themselves rather than expecting SQLite to deal with it for them. 5011** This is different from every other SQLite interface. The inconsistency 5012** is unfortunate but cannot be changed without breaking backwards 5013** compatibility. 5014** 5015** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5016*/ 5017int sqlite3_create_collation( 5018 sqlite3*, 5019 const char *zName, 5020 int eTextRep, 5021 void *pArg, 5022 int(*xCompare)(void*,int,const void*,int,const void*) 5023); 5024int sqlite3_create_collation_v2( 5025 sqlite3*, 5026 const char *zName, 5027 int eTextRep, 5028 void *pArg, 5029 int(*xCompare)(void*,int,const void*,int,const void*), 5030 void(*xDestroy)(void*) 5031); 5032int sqlite3_create_collation16( 5033 sqlite3*, 5034 const void *zName, 5035 int eTextRep, 5036 void *pArg, 5037 int(*xCompare)(void*,int,const void*,int,const void*) 5038); 5039 5040/* 5041** CAPI3REF: Collation Needed Callbacks 5042** METHOD: sqlite3 5043** 5044** ^To avoid having to register all collation sequences before a database 5045** can be used, a single callback function may be registered with the 5046** [database connection] to be invoked whenever an undefined collation 5047** sequence is required. 5048** 5049** ^If the function is registered using the sqlite3_collation_needed() API, 5050** then it is passed the names of undefined collation sequences as strings 5051** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5052** the names are passed as UTF-16 in machine native byte order. 5053** ^A call to either function replaces the existing collation-needed callback. 5054** 5055** ^(When the callback is invoked, the first argument passed is a copy 5056** of the second argument to sqlite3_collation_needed() or 5057** sqlite3_collation_needed16(). The second argument is the database 5058** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5059** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5060** sequence function required. The fourth parameter is the name of the 5061** required collation sequence.)^ 5062** 5063** The callback function should register the desired collation using 5064** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5065** [sqlite3_create_collation_v2()]. 5066*/ 5067int sqlite3_collation_needed( 5068 sqlite3*, 5069 void*, 5070 void(*)(void*,sqlite3*,int eTextRep,const char*) 5071); 5072int sqlite3_collation_needed16( 5073 sqlite3*, 5074 void*, 5075 void(*)(void*,sqlite3*,int eTextRep,const void*) 5076); 5077 5078#ifdef SQLITE_HAS_CODEC 5079/* 5080** Specify the key for an encrypted database. This routine should be 5081** called right after sqlite3_open(). 5082** 5083** The code to implement this API is not available in the public release 5084** of SQLite. 5085*/ 5086int sqlite3_key( 5087 sqlite3 *db, /* Database to be rekeyed */ 5088 const void *pKey, int nKey /* The key */ 5089); 5090int sqlite3_key_v2( 5091 sqlite3 *db, /* Database to be rekeyed */ 5092 const char *zDbName, /* Name of the database */ 5093 const void *pKey, int nKey /* The key */ 5094); 5095 5096/* 5097** Change the key on an open database. If the current database is not 5098** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 5099** database is decrypted. 5100** 5101** The code to implement this API is not available in the public release 5102** of SQLite. 5103*/ 5104int sqlite3_rekey( 5105 sqlite3 *db, /* Database to be rekeyed */ 5106 const void *pKey, int nKey /* The new key */ 5107); 5108int sqlite3_rekey_v2( 5109 sqlite3 *db, /* Database to be rekeyed */ 5110 const char *zDbName, /* Name of the database */ 5111 const void *pKey, int nKey /* The new key */ 5112); 5113 5114/* 5115** Specify the activation key for a SEE database. Unless 5116** activated, none of the SEE routines will work. 5117*/ 5118void sqlite3_activate_see( 5119 const char *zPassPhrase /* Activation phrase */ 5120); 5121#endif 5122 5123#ifdef SQLITE_ENABLE_CEROD 5124/* 5125** Specify the activation key for a CEROD database. Unless 5126** activated, none of the CEROD routines will work. 5127*/ 5128void sqlite3_activate_cerod( 5129 const char *zPassPhrase /* Activation phrase */ 5130); 5131#endif 5132 5133/* 5134** CAPI3REF: Suspend Execution For A Short Time 5135** 5136** The sqlite3_sleep() function causes the current thread to suspend execution 5137** for at least a number of milliseconds specified in its parameter. 5138** 5139** If the operating system does not support sleep requests with 5140** millisecond time resolution, then the time will be rounded up to 5141** the nearest second. The number of milliseconds of sleep actually 5142** requested from the operating system is returned. 5143** 5144** ^SQLite implements this interface by calling the xSleep() 5145** method of the default [sqlite3_vfs] object. If the xSleep() method 5146** of the default VFS is not implemented correctly, or not implemented at 5147** all, then the behavior of sqlite3_sleep() may deviate from the description 5148** in the previous paragraphs. 5149*/ 5150int sqlite3_sleep(int); 5151 5152/* 5153** CAPI3REF: Name Of The Folder Holding Temporary Files 5154** 5155** ^(If this global variable is made to point to a string which is 5156** the name of a folder (a.k.a. directory), then all temporary files 5157** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5158** will be placed in that directory.)^ ^If this variable 5159** is a NULL pointer, then SQLite performs a search for an appropriate 5160** temporary file directory. 5161** 5162** Applications are strongly discouraged from using this global variable. 5163** It is required to set a temporary folder on Windows Runtime (WinRT). 5164** But for all other platforms, it is highly recommended that applications 5165** neither read nor write this variable. This global variable is a relic 5166** that exists for backwards compatibility of legacy applications and should 5167** be avoided in new projects. 5168** 5169** It is not safe to read or modify this variable in more than one 5170** thread at a time. It is not safe to read or modify this variable 5171** if a [database connection] is being used at the same time in a separate 5172** thread. 5173** It is intended that this variable be set once 5174** as part of process initialization and before any SQLite interface 5175** routines have been called and that this variable remain unchanged 5176** thereafter. 5177** 5178** ^The [temp_store_directory pragma] may modify this variable and cause 5179** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5180** the [temp_store_directory pragma] always assumes that any string 5181** that this variable points to is held in memory obtained from 5182** [sqlite3_malloc] and the pragma may attempt to free that memory 5183** using [sqlite3_free]. 5184** Hence, if this variable is modified directly, either it should be 5185** made NULL or made to point to memory obtained from [sqlite3_malloc] 5186** or else the use of the [temp_store_directory pragma] should be avoided. 5187** Except when requested by the [temp_store_directory pragma], SQLite 5188** does not free the memory that sqlite3_temp_directory points to. If 5189** the application wants that memory to be freed, it must do 5190** so itself, taking care to only do so after all [database connection] 5191** objects have been destroyed. 5192** 5193** <b>Note to Windows Runtime users:</b> The temporary directory must be set 5194** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 5195** features that require the use of temporary files may fail. Here is an 5196** example of how to do this using C++ with the Windows Runtime: 5197** 5198** <blockquote><pre> 5199** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 5200** TemporaryFolder->Path->Data(); 5201** char zPathBuf[MAX_PATH + 1]; 5202** memset(zPathBuf, 0, sizeof(zPathBuf)); 5203** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 5204** NULL, NULL); 5205** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 5206** </pre></blockquote> 5207*/ 5208SQLITE_EXTERN char *sqlite3_temp_directory; 5209 5210/* 5211** CAPI3REF: Name Of The Folder Holding Database Files 5212** 5213** ^(If this global variable is made to point to a string which is 5214** the name of a folder (a.k.a. directory), then all database files 5215** specified with a relative pathname and created or accessed by 5216** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 5217** to be relative to that directory.)^ ^If this variable is a NULL 5218** pointer, then SQLite assumes that all database files specified 5219** with a relative pathname are relative to the current directory 5220** for the process. Only the windows VFS makes use of this global 5221** variable; it is ignored by the unix VFS. 5222** 5223** Changing the value of this variable while a database connection is 5224** open can result in a corrupt database. 5225** 5226** It is not safe to read or modify this variable in more than one 5227** thread at a time. It is not safe to read or modify this variable 5228** if a [database connection] is being used at the same time in a separate 5229** thread. 5230** It is intended that this variable be set once 5231** as part of process initialization and before any SQLite interface 5232** routines have been called and that this variable remain unchanged 5233** thereafter. 5234** 5235** ^The [data_store_directory pragma] may modify this variable and cause 5236** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5237** the [data_store_directory pragma] always assumes that any string 5238** that this variable points to is held in memory obtained from 5239** [sqlite3_malloc] and the pragma may attempt to free that memory 5240** using [sqlite3_free]. 5241** Hence, if this variable is modified directly, either it should be 5242** made NULL or made to point to memory obtained from [sqlite3_malloc] 5243** or else the use of the [data_store_directory pragma] should be avoided. 5244*/ 5245SQLITE_EXTERN char *sqlite3_data_directory; 5246 5247/* 5248** CAPI3REF: Test For Auto-Commit Mode 5249** KEYWORDS: {autocommit mode} 5250** METHOD: sqlite3 5251** 5252** ^The sqlite3_get_autocommit() interface returns non-zero or 5253** zero if the given database connection is or is not in autocommit mode, 5254** respectively. ^Autocommit mode is on by default. 5255** ^Autocommit mode is disabled by a [BEGIN] statement. 5256** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5257** 5258** If certain kinds of errors occur on a statement within a multi-statement 5259** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5260** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5261** transaction might be rolled back automatically. The only way to 5262** find out whether SQLite automatically rolled back the transaction after 5263** an error is to use this function. 5264** 5265** If another thread changes the autocommit status of the database 5266** connection while this routine is running, then the return value 5267** is undefined. 5268*/ 5269int sqlite3_get_autocommit(sqlite3*); 5270 5271/* 5272** CAPI3REF: Find The Database Handle Of A Prepared Statement 5273** METHOD: sqlite3_stmt 5274** 5275** ^The sqlite3_db_handle interface returns the [database connection] handle 5276** to which a [prepared statement] belongs. ^The [database connection] 5277** returned by sqlite3_db_handle is the same [database connection] 5278** that was the first argument 5279** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5280** create the statement in the first place. 5281*/ 5282sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5283 5284/* 5285** CAPI3REF: Return The Filename For A Database Connection 5286** METHOD: sqlite3 5287** 5288** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5289** associated with database N of connection D. ^The main database file 5290** has the name "main". If there is no attached database N on the database 5291** connection D, or if database N is a temporary or in-memory database, then 5292** a NULL pointer is returned. 5293** 5294** ^The filename returned by this function is the output of the 5295** xFullPathname method of the [VFS]. ^In other words, the filename 5296** will be an absolute pathname, even if the filename used 5297** to open the database originally was a URI or relative pathname. 5298*/ 5299const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5300 5301/* 5302** CAPI3REF: Determine if a database is read-only 5303** METHOD: sqlite3 5304** 5305** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5306** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5307** the name of a database on connection D. 5308*/ 5309int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5310 5311/* 5312** CAPI3REF: Find the next prepared statement 5313** METHOD: sqlite3 5314** 5315** ^This interface returns a pointer to the next [prepared statement] after 5316** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5317** then this interface returns a pointer to the first prepared statement 5318** associated with the database connection pDb. ^If no prepared statement 5319** satisfies the conditions of this routine, it returns NULL. 5320** 5321** The [database connection] pointer D in a call to 5322** [sqlite3_next_stmt(D,S)] must refer to an open database 5323** connection and in particular must not be a NULL pointer. 5324*/ 5325sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5326 5327/* 5328** CAPI3REF: Commit And Rollback Notification Callbacks 5329** METHOD: sqlite3 5330** 5331** ^The sqlite3_commit_hook() interface registers a callback 5332** function to be invoked whenever a transaction is [COMMIT | committed]. 5333** ^Any callback set by a previous call to sqlite3_commit_hook() 5334** for the same database connection is overridden. 5335** ^The sqlite3_rollback_hook() interface registers a callback 5336** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5337** ^Any callback set by a previous call to sqlite3_rollback_hook() 5338** for the same database connection is overridden. 5339** ^The pArg argument is passed through to the callback. 5340** ^If the callback on a commit hook function returns non-zero, 5341** then the commit is converted into a rollback. 5342** 5343** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5344** return the P argument from the previous call of the same function 5345** on the same [database connection] D, or NULL for 5346** the first call for each function on D. 5347** 5348** The commit and rollback hook callbacks are not reentrant. 5349** The callback implementation must not do anything that will modify 5350** the database connection that invoked the callback. Any actions 5351** to modify the database connection must be deferred until after the 5352** completion of the [sqlite3_step()] call that triggered the commit 5353** or rollback hook in the first place. 5354** Note that running any other SQL statements, including SELECT statements, 5355** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5356** the database connections for the meaning of "modify" in this paragraph. 5357** 5358** ^Registering a NULL function disables the callback. 5359** 5360** ^When the commit hook callback routine returns zero, the [COMMIT] 5361** operation is allowed to continue normally. ^If the commit hook 5362** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5363** ^The rollback hook is invoked on a rollback that results from a commit 5364** hook returning non-zero, just as it would be with any other rollback. 5365** 5366** ^For the purposes of this API, a transaction is said to have been 5367** rolled back if an explicit "ROLLBACK" statement is executed, or 5368** an error or constraint causes an implicit rollback to occur. 5369** ^The rollback callback is not invoked if a transaction is 5370** automatically rolled back because the database connection is closed. 5371** 5372** See also the [sqlite3_update_hook()] interface. 5373*/ 5374void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5375void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5376 5377/* 5378** CAPI3REF: Data Change Notification Callbacks 5379** METHOD: sqlite3 5380** 5381** ^The sqlite3_update_hook() interface registers a callback function 5382** with the [database connection] identified by the first argument 5383** to be invoked whenever a row is updated, inserted or deleted in 5384** a [rowid table]. 5385** ^Any callback set by a previous call to this function 5386** for the same database connection is overridden. 5387** 5388** ^The second argument is a pointer to the function to invoke when a 5389** row is updated, inserted or deleted in a rowid table. 5390** ^The first argument to the callback is a copy of the third argument 5391** to sqlite3_update_hook(). 5392** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5393** or [SQLITE_UPDATE], depending on the operation that caused the callback 5394** to be invoked. 5395** ^The third and fourth arguments to the callback contain pointers to the 5396** database and table name containing the affected row. 5397** ^The final callback parameter is the [rowid] of the row. 5398** ^In the case of an update, this is the [rowid] after the update takes place. 5399** 5400** ^(The update hook is not invoked when internal system tables are 5401** modified (i.e. sqlite_master and sqlite_sequence).)^ 5402** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5403** 5404** ^In the current implementation, the update hook 5405** is not invoked when duplication rows are deleted because of an 5406** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5407** invoked when rows are deleted using the [truncate optimization]. 5408** The exceptions defined in this paragraph might change in a future 5409** release of SQLite. 5410** 5411** The update hook implementation must not do anything that will modify 5412** the database connection that invoked the update hook. Any actions 5413** to modify the database connection must be deferred until after the 5414** completion of the [sqlite3_step()] call that triggered the update hook. 5415** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5416** database connections for the meaning of "modify" in this paragraph. 5417** 5418** ^The sqlite3_update_hook(D,C,P) function 5419** returns the P argument from the previous call 5420** on the same [database connection] D, or NULL for 5421** the first call on D. 5422** 5423** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 5424** and [sqlite3_preupdate_hook()] interfaces. 5425*/ 5426void *sqlite3_update_hook( 5427 sqlite3*, 5428 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5429 void* 5430); 5431 5432/* 5433** CAPI3REF: Enable Or Disable Shared Pager Cache 5434** 5435** ^(This routine enables or disables the sharing of the database cache 5436** and schema data structures between [database connection | connections] 5437** to the same database. Sharing is enabled if the argument is true 5438** and disabled if the argument is false.)^ 5439** 5440** ^Cache sharing is enabled and disabled for an entire process. 5441** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 5442** In prior versions of SQLite, 5443** sharing was enabled or disabled for each thread separately. 5444** 5445** ^(The cache sharing mode set by this interface effects all subsequent 5446** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5447** Existing database connections continue use the sharing mode 5448** that was in effect at the time they were opened.)^ 5449** 5450** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5451** successfully. An [error code] is returned otherwise.)^ 5452** 5453** ^Shared cache is disabled by default. But this might change in 5454** future releases of SQLite. Applications that care about shared 5455** cache setting should set it explicitly. 5456** 5457** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5458** and will always return SQLITE_MISUSE. On those systems, 5459** shared cache mode should be enabled per-database connection via 5460** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5461** 5462** This interface is threadsafe on processors where writing a 5463** 32-bit integer is atomic. 5464** 5465** See Also: [SQLite Shared-Cache Mode] 5466*/ 5467int sqlite3_enable_shared_cache(int); 5468 5469/* 5470** CAPI3REF: Attempt To Free Heap Memory 5471** 5472** ^The sqlite3_release_memory() interface attempts to free N bytes 5473** of heap memory by deallocating non-essential memory allocations 5474** held by the database library. Memory used to cache database 5475** pages to improve performance is an example of non-essential memory. 5476** ^sqlite3_release_memory() returns the number of bytes actually freed, 5477** which might be more or less than the amount requested. 5478** ^The sqlite3_release_memory() routine is a no-op returning zero 5479** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5480** 5481** See also: [sqlite3_db_release_memory()] 5482*/ 5483int sqlite3_release_memory(int); 5484 5485/* 5486** CAPI3REF: Free Memory Used By A Database Connection 5487** METHOD: sqlite3 5488** 5489** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5490** memory as possible from database connection D. Unlike the 5491** [sqlite3_release_memory()] interface, this interface is in effect even 5492** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5493** omitted. 5494** 5495** See also: [sqlite3_release_memory()] 5496*/ 5497int sqlite3_db_release_memory(sqlite3*); 5498 5499/* 5500** CAPI3REF: Impose A Limit On Heap Size 5501** 5502** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5503** soft limit on the amount of heap memory that may be allocated by SQLite. 5504** ^SQLite strives to keep heap memory utilization below the soft heap 5505** limit by reducing the number of pages held in the page cache 5506** as heap memory usages approaches the limit. 5507** ^The soft heap limit is "soft" because even though SQLite strives to stay 5508** below the limit, it will exceed the limit rather than generate 5509** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5510** is advisory only. 5511** 5512** ^The return value from sqlite3_soft_heap_limit64() is the size of 5513** the soft heap limit prior to the call, or negative in the case of an 5514** error. ^If the argument N is negative 5515** then no change is made to the soft heap limit. Hence, the current 5516** size of the soft heap limit can be determined by invoking 5517** sqlite3_soft_heap_limit64() with a negative argument. 5518** 5519** ^If the argument N is zero then the soft heap limit is disabled. 5520** 5521** ^(The soft heap limit is not enforced in the current implementation 5522** if one or more of following conditions are true: 5523** 5524** <ul> 5525** <li> The soft heap limit is set to zero. 5526** <li> Memory accounting is disabled using a combination of the 5527** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5528** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5529** <li> An alternative page cache implementation is specified using 5530** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5531** <li> The page cache allocates from its own memory pool supplied 5532** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5533** from the heap. 5534** </ul>)^ 5535** 5536** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]), 5537** the soft heap limit is enforced 5538** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5539** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5540** the soft heap limit is enforced on every memory allocation. Without 5541** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5542** when memory is allocated by the page cache. Testing suggests that because 5543** the page cache is the predominate memory user in SQLite, most 5544** applications will achieve adequate soft heap limit enforcement without 5545** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5546** 5547** The circumstances under which SQLite will enforce the soft heap limit may 5548** changes in future releases of SQLite. 5549*/ 5550sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5551 5552/* 5553** CAPI3REF: Deprecated Soft Heap Limit Interface 5554** DEPRECATED 5555** 5556** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5557** interface. This routine is provided for historical compatibility 5558** only. All new applications should use the 5559** [sqlite3_soft_heap_limit64()] interface rather than this one. 5560*/ 5561SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5562 5563 5564/* 5565** CAPI3REF: Extract Metadata About A Column Of A Table 5566** METHOD: sqlite3 5567** 5568** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5569** information about column C of table T in database D 5570** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5571** interface returns SQLITE_OK and fills in the non-NULL pointers in 5572** the final five arguments with appropriate values if the specified 5573** column exists. ^The sqlite3_table_column_metadata() interface returns 5574** SQLITE_ERROR and if the specified column does not exist. 5575** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5576** NULL pointer, then this routine simply checks for the existence of the 5577** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5578** does not. 5579** 5580** ^The column is identified by the second, third and fourth parameters to 5581** this function. ^(The second parameter is either the name of the database 5582** (i.e. "main", "temp", or an attached database) containing the specified 5583** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5584** for the table using the same algorithm used by the database engine to 5585** resolve unqualified table references. 5586** 5587** ^The third and fourth parameters to this function are the table and column 5588** name of the desired column, respectively. 5589** 5590** ^Metadata is returned by writing to the memory locations passed as the 5th 5591** and subsequent parameters to this function. ^Any of these arguments may be 5592** NULL, in which case the corresponding element of metadata is omitted. 5593** 5594** ^(<blockquote> 5595** <table border="1"> 5596** <tr><th> Parameter <th> Output<br>Type <th> Description 5597** 5598** <tr><td> 5th <td> const char* <td> Data type 5599** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5600** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5601** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5602** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5603** </table> 5604** </blockquote>)^ 5605** 5606** ^The memory pointed to by the character pointers returned for the 5607** declaration type and collation sequence is valid until the next 5608** call to any SQLite API function. 5609** 5610** ^If the specified table is actually a view, an [error code] is returned. 5611** 5612** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5613** is not a [WITHOUT ROWID] table and an 5614** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5615** parameters are set for the explicitly declared column. ^(If there is no 5616** [INTEGER PRIMARY KEY] column, then the outputs 5617** for the [rowid] are set as follows: 5618** 5619** <pre> 5620** data type: "INTEGER" 5621** collation sequence: "BINARY" 5622** not null: 0 5623** primary key: 1 5624** auto increment: 0 5625** </pre>)^ 5626** 5627** ^This function causes all database schemas to be read from disk and 5628** parsed, if that has not already been done, and returns an error if 5629** any errors are encountered while loading the schema. 5630*/ 5631int sqlite3_table_column_metadata( 5632 sqlite3 *db, /* Connection handle */ 5633 const char *zDbName, /* Database name or NULL */ 5634 const char *zTableName, /* Table name */ 5635 const char *zColumnName, /* Column name */ 5636 char const **pzDataType, /* OUTPUT: Declared data type */ 5637 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5638 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5639 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5640 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5641); 5642 5643/* 5644** CAPI3REF: Load An Extension 5645** METHOD: sqlite3 5646** 5647** ^This interface loads an SQLite extension library from the named file. 5648** 5649** ^The sqlite3_load_extension() interface attempts to load an 5650** [SQLite extension] library contained in the file zFile. If 5651** the file cannot be loaded directly, attempts are made to load 5652** with various operating-system specific extensions added. 5653** So for example, if "samplelib" cannot be loaded, then names like 5654** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5655** be tried also. 5656** 5657** ^The entry point is zProc. 5658** ^(zProc may be 0, in which case SQLite will try to come up with an 5659** entry point name on its own. It first tries "sqlite3_extension_init". 5660** If that does not work, it constructs a name "sqlite3_X_init" where the 5661** X is consists of the lower-case equivalent of all ASCII alphabetic 5662** characters in the filename from the last "/" to the first following 5663** "." and omitting any initial "lib".)^ 5664** ^The sqlite3_load_extension() interface returns 5665** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5666** ^If an error occurs and pzErrMsg is not 0, then the 5667** [sqlite3_load_extension()] interface shall attempt to 5668** fill *pzErrMsg with error message text stored in memory 5669** obtained from [sqlite3_malloc()]. The calling function 5670** should free this memory by calling [sqlite3_free()]. 5671** 5672** ^Extension loading must be enabled using 5673** [sqlite3_enable_load_extension()] or 5674** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 5675** prior to calling this API, 5676** otherwise an error will be returned. 5677** 5678** <b>Security warning:</b> It is recommended that the 5679** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 5680** interface. The use of the [sqlite3_enable_load_extension()] interface 5681** should be avoided. This will keep the SQL function [load_extension()] 5682** disabled and prevent SQL injections from giving attackers 5683** access to extension loading capabilities. 5684** 5685** See also the [load_extension() SQL function]. 5686*/ 5687int sqlite3_load_extension( 5688 sqlite3 *db, /* Load the extension into this database connection */ 5689 const char *zFile, /* Name of the shared library containing extension */ 5690 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5691 char **pzErrMsg /* Put error message here if not 0 */ 5692); 5693 5694/* 5695** CAPI3REF: Enable Or Disable Extension Loading 5696** METHOD: sqlite3 5697** 5698** ^So as not to open security holes in older applications that are 5699** unprepared to deal with [extension loading], and as a means of disabling 5700** [extension loading] while evaluating user-entered SQL, the following API 5701** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5702** 5703** ^Extension loading is off by default. 5704** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5705** to turn extension loading on and call it with onoff==0 to turn 5706** it back off again. 5707** 5708** ^This interface enables or disables both the C-API 5709** [sqlite3_load_extension()] and the SQL function [load_extension()]. 5710** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 5711** to enable or disable only the C-API.)^ 5712** 5713** <b>Security warning:</b> It is recommended that extension loading 5714** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 5715** rather than this interface, so the [load_extension()] SQL function 5716** remains disabled. This will prevent SQL injections from giving attackers 5717** access to extension loading capabilities. 5718*/ 5719int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5720 5721/* 5722** CAPI3REF: Automatically Load Statically Linked Extensions 5723** 5724** ^This interface causes the xEntryPoint() function to be invoked for 5725** each new [database connection] that is created. The idea here is that 5726** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5727** that is to be automatically loaded into all new database connections. 5728** 5729** ^(Even though the function prototype shows that xEntryPoint() takes 5730** no arguments and returns void, SQLite invokes xEntryPoint() with three 5731** arguments and expects an integer result as if the signature of the 5732** entry point where as follows: 5733** 5734** <blockquote><pre> 5735** int xEntryPoint( 5736** sqlite3 *db, 5737** const char **pzErrMsg, 5738** const struct sqlite3_api_routines *pThunk 5739** ); 5740** </pre></blockquote>)^ 5741** 5742** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5743** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5744** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5745** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5746** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5747** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5748** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 5749** 5750** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 5751** on the list of automatic extensions is a harmless no-op. ^No entry point 5752** will be called more than once for each database connection that is opened. 5753** 5754** See also: [sqlite3_reset_auto_extension()] 5755** and [sqlite3_cancel_auto_extension()] 5756*/ 5757int sqlite3_auto_extension(void(*xEntryPoint)(void)); 5758 5759/* 5760** CAPI3REF: Cancel Automatic Extension Loading 5761** 5762** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 5763** initialization routine X that was registered using a prior call to 5764** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 5765** routine returns 1 if initialization routine X was successfully 5766** unregistered and it returns 0 if X was not on the list of initialization 5767** routines. 5768*/ 5769int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 5770 5771/* 5772** CAPI3REF: Reset Automatic Extension Loading 5773** 5774** ^This interface disables all automatic extensions previously 5775** registered using [sqlite3_auto_extension()]. 5776*/ 5777void sqlite3_reset_auto_extension(void); 5778 5779/* 5780** The interface to the virtual-table mechanism is currently considered 5781** to be experimental. The interface might change in incompatible ways. 5782** If this is a problem for you, do not use the interface at this time. 5783** 5784** When the virtual-table mechanism stabilizes, we will declare the 5785** interface fixed, support it indefinitely, and remove this comment. 5786*/ 5787 5788/* 5789** Structures used by the virtual table interface 5790*/ 5791typedef struct sqlite3_vtab sqlite3_vtab; 5792typedef struct sqlite3_index_info sqlite3_index_info; 5793typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 5794typedef struct sqlite3_module sqlite3_module; 5795 5796/* 5797** CAPI3REF: Virtual Table Object 5798** KEYWORDS: sqlite3_module {virtual table module} 5799** 5800** This structure, sometimes called a "virtual table module", 5801** defines the implementation of a [virtual tables]. 5802** This structure consists mostly of methods for the module. 5803** 5804** ^A virtual table module is created by filling in a persistent 5805** instance of this structure and passing a pointer to that instance 5806** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 5807** ^The registration remains valid until it is replaced by a different 5808** module or until the [database connection] closes. The content 5809** of this structure must not change while it is registered with 5810** any database connection. 5811*/ 5812struct sqlite3_module { 5813 int iVersion; 5814 int (*xCreate)(sqlite3*, void *pAux, 5815 int argc, const char *const*argv, 5816 sqlite3_vtab **ppVTab, char**); 5817 int (*xConnect)(sqlite3*, void *pAux, 5818 int argc, const char *const*argv, 5819 sqlite3_vtab **ppVTab, char**); 5820 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 5821 int (*xDisconnect)(sqlite3_vtab *pVTab); 5822 int (*xDestroy)(sqlite3_vtab *pVTab); 5823 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 5824 int (*xClose)(sqlite3_vtab_cursor*); 5825 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 5826 int argc, sqlite3_value **argv); 5827 int (*xNext)(sqlite3_vtab_cursor*); 5828 int (*xEof)(sqlite3_vtab_cursor*); 5829 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 5830 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 5831 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 5832 int (*xBegin)(sqlite3_vtab *pVTab); 5833 int (*xSync)(sqlite3_vtab *pVTab); 5834 int (*xCommit)(sqlite3_vtab *pVTab); 5835 int (*xRollback)(sqlite3_vtab *pVTab); 5836 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 5837 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 5838 void **ppArg); 5839 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 5840 /* The methods above are in version 1 of the sqlite_module object. Those 5841 ** below are for version 2 and greater. */ 5842 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 5843 int (*xRelease)(sqlite3_vtab *pVTab, int); 5844 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 5845}; 5846 5847/* 5848** CAPI3REF: Virtual Table Indexing Information 5849** KEYWORDS: sqlite3_index_info 5850** 5851** The sqlite3_index_info structure and its substructures is used as part 5852** of the [virtual table] interface to 5853** pass information into and receive the reply from the [xBestIndex] 5854** method of a [virtual table module]. The fields under **Inputs** are the 5855** inputs to xBestIndex and are read-only. xBestIndex inserts its 5856** results into the **Outputs** fields. 5857** 5858** ^(The aConstraint[] array records WHERE clause constraints of the form: 5859** 5860** <blockquote>column OP expr</blockquote> 5861** 5862** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 5863** stored in aConstraint[].op using one of the 5864** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 5865** ^(The index of the column is stored in 5866** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5867** expr on the right-hand side can be evaluated (and thus the constraint 5868** is usable) and false if it cannot.)^ 5869** 5870** ^The optimizer automatically inverts terms of the form "expr OP column" 5871** and makes other simplifications to the WHERE clause in an attempt to 5872** get as many WHERE clause terms into the form shown above as possible. 5873** ^The aConstraint[] array only reports WHERE clause terms that are 5874** relevant to the particular virtual table being queried. 5875** 5876** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5877** ^Each term of aOrderBy records a column of the ORDER BY clause. 5878** 5879** The colUsed field indicates which columns of the virtual table may be 5880** required by the current scan. Virtual table columns are numbered from 5881** zero in the order in which they appear within the CREATE TABLE statement 5882** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 5883** the corresponding bit is set within the colUsed mask if the column may be 5884** required by SQLite. If the table has at least 64 columns and any column 5885** to the right of the first 63 is required, then bit 63 of colUsed is also 5886** set. In other words, column iCol may be required if the expression 5887** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 5888** non-zero. 5889** 5890** The [xBestIndex] method must fill aConstraintUsage[] with information 5891** about what parameters to pass to xFilter. ^If argvIndex>0 then 5892** the right-hand side of the corresponding aConstraint[] is evaluated 5893** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5894** is true, then the constraint is assumed to be fully handled by the 5895** virtual table and is not checked again by SQLite.)^ 5896** 5897** ^The idxNum and idxPtr values are recorded and passed into the 5898** [xFilter] method. 5899** ^[sqlite3_free()] is used to free idxPtr if and only if 5900** needToFreeIdxPtr is true. 5901** 5902** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5903** the correct order to satisfy the ORDER BY clause so that no separate 5904** sorting step is required. 5905** 5906** ^The estimatedCost value is an estimate of the cost of a particular 5907** strategy. A cost of N indicates that the cost of the strategy is similar 5908** to a linear scan of an SQLite table with N rows. A cost of log(N) 5909** indicates that the expense of the operation is similar to that of a 5910** binary search on a unique indexed field of an SQLite table with N rows. 5911** 5912** ^The estimatedRows value is an estimate of the number of rows that 5913** will be returned by the strategy. 5914** 5915** The xBestIndex method may optionally populate the idxFlags field with a 5916** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 5917** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 5918** assumes that the strategy may visit at most one row. 5919** 5920** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 5921** SQLite also assumes that if a call to the xUpdate() method is made as 5922** part of the same statement to delete or update a virtual table row and the 5923** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 5924** any database changes. In other words, if the xUpdate() returns 5925** SQLITE_CONSTRAINT, the database contents must be exactly as they were 5926** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 5927** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 5928** the xUpdate method are automatically rolled back by SQLite. 5929** 5930** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 5931** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 5932** If a virtual table extension is 5933** used with an SQLite version earlier than 3.8.2, the results of attempting 5934** to read or write the estimatedRows field are undefined (but are likely 5935** to included crashing the application). The estimatedRows field should 5936** therefore only be used if [sqlite3_libversion_number()] returns a 5937** value greater than or equal to 3008002. Similarly, the idxFlags field 5938** was added for [version 3.9.0] ([dateof:3.9.0]). 5939** It may therefore only be used if 5940** sqlite3_libversion_number() returns a value greater than or equal to 5941** 3009000. 5942*/ 5943struct sqlite3_index_info { 5944 /* Inputs */ 5945 int nConstraint; /* Number of entries in aConstraint */ 5946 struct sqlite3_index_constraint { 5947 int iColumn; /* Column constrained. -1 for ROWID */ 5948 unsigned char op; /* Constraint operator */ 5949 unsigned char usable; /* True if this constraint is usable */ 5950 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5951 } *aConstraint; /* Table of WHERE clause constraints */ 5952 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5953 struct sqlite3_index_orderby { 5954 int iColumn; /* Column number */ 5955 unsigned char desc; /* True for DESC. False for ASC. */ 5956 } *aOrderBy; /* The ORDER BY clause */ 5957 /* Outputs */ 5958 struct sqlite3_index_constraint_usage { 5959 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5960 unsigned char omit; /* Do not code a test for this constraint */ 5961 } *aConstraintUsage; 5962 int idxNum; /* Number used to identify the index */ 5963 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5964 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5965 int orderByConsumed; /* True if output is already ordered */ 5966 double estimatedCost; /* Estimated cost of using this index */ 5967 /* Fields below are only available in SQLite 3.8.2 and later */ 5968 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 5969 /* Fields below are only available in SQLite 3.9.0 and later */ 5970 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 5971 /* Fields below are only available in SQLite 3.10.0 and later */ 5972 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 5973}; 5974 5975/* 5976** CAPI3REF: Virtual Table Scan Flags 5977*/ 5978#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 5979 5980/* 5981** CAPI3REF: Virtual Table Constraint Operator Codes 5982** 5983** These macros defined the allowed values for the 5984** [sqlite3_index_info].aConstraint[].op field. Each value represents 5985** an operator that is part of a constraint term in the wHERE clause of 5986** a query that uses a [virtual table]. 5987*/ 5988#define SQLITE_INDEX_CONSTRAINT_EQ 2 5989#define SQLITE_INDEX_CONSTRAINT_GT 4 5990#define SQLITE_INDEX_CONSTRAINT_LE 8 5991#define SQLITE_INDEX_CONSTRAINT_LT 16 5992#define SQLITE_INDEX_CONSTRAINT_GE 32 5993#define SQLITE_INDEX_CONSTRAINT_MATCH 64 5994#define SQLITE_INDEX_CONSTRAINT_LIKE 65 5995#define SQLITE_INDEX_CONSTRAINT_GLOB 66 5996#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 5997 5998/* 5999** CAPI3REF: Register A Virtual Table Implementation 6000** METHOD: sqlite3 6001** 6002** ^These routines are used to register a new [virtual table module] name. 6003** ^Module names must be registered before 6004** creating a new [virtual table] using the module and before using a 6005** preexisting [virtual table] for the module. 6006** 6007** ^The module name is registered on the [database connection] specified 6008** by the first parameter. ^The name of the module is given by the 6009** second parameter. ^The third parameter is a pointer to 6010** the implementation of the [virtual table module]. ^The fourth 6011** parameter is an arbitrary client data pointer that is passed through 6012** into the [xCreate] and [xConnect] methods of the virtual table module 6013** when a new virtual table is be being created or reinitialized. 6014** 6015** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6016** is a pointer to a destructor for the pClientData. ^SQLite will 6017** invoke the destructor function (if it is not NULL) when SQLite 6018** no longer needs the pClientData pointer. ^The destructor will also 6019** be invoked if the call to sqlite3_create_module_v2() fails. 6020** ^The sqlite3_create_module() 6021** interface is equivalent to sqlite3_create_module_v2() with a NULL 6022** destructor. 6023*/ 6024int sqlite3_create_module( 6025 sqlite3 *db, /* SQLite connection to register module with */ 6026 const char *zName, /* Name of the module */ 6027 const sqlite3_module *p, /* Methods for the module */ 6028 void *pClientData /* Client data for xCreate/xConnect */ 6029); 6030int sqlite3_create_module_v2( 6031 sqlite3 *db, /* SQLite connection to register module with */ 6032 const char *zName, /* Name of the module */ 6033 const sqlite3_module *p, /* Methods for the module */ 6034 void *pClientData, /* Client data for xCreate/xConnect */ 6035 void(*xDestroy)(void*) /* Module destructor function */ 6036); 6037 6038/* 6039** CAPI3REF: Virtual Table Instance Object 6040** KEYWORDS: sqlite3_vtab 6041** 6042** Every [virtual table module] implementation uses a subclass 6043** of this object to describe a particular instance 6044** of the [virtual table]. Each subclass will 6045** be tailored to the specific needs of the module implementation. 6046** The purpose of this superclass is to define certain fields that are 6047** common to all module implementations. 6048** 6049** ^Virtual tables methods can set an error message by assigning a 6050** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 6051** take care that any prior string is freed by a call to [sqlite3_free()] 6052** prior to assigning a new string to zErrMsg. ^After the error message 6053** is delivered up to the client application, the string will be automatically 6054** freed by sqlite3_free() and the zErrMsg field will be zeroed. 6055*/ 6056struct sqlite3_vtab { 6057 const sqlite3_module *pModule; /* The module for this virtual table */ 6058 int nRef; /* Number of open cursors */ 6059 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 6060 /* Virtual table implementations will typically add additional fields */ 6061}; 6062 6063/* 6064** CAPI3REF: Virtual Table Cursor Object 6065** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 6066** 6067** Every [virtual table module] implementation uses a subclass of the 6068** following structure to describe cursors that point into the 6069** [virtual table] and are used 6070** to loop through the virtual table. Cursors are created using the 6071** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 6072** by the [sqlite3_module.xClose | xClose] method. Cursors are used 6073** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 6074** of the module. Each module implementation will define 6075** the content of a cursor structure to suit its own needs. 6076** 6077** This superclass exists in order to define fields of the cursor that 6078** are common to all implementations. 6079*/ 6080struct sqlite3_vtab_cursor { 6081 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 6082 /* Virtual table implementations will typically add additional fields */ 6083}; 6084 6085/* 6086** CAPI3REF: Declare The Schema Of A Virtual Table 6087** 6088** ^The [xCreate] and [xConnect] methods of a 6089** [virtual table module] call this interface 6090** to declare the format (the names and datatypes of the columns) of 6091** the virtual tables they implement. 6092*/ 6093int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 6094 6095/* 6096** CAPI3REF: Overload A Function For A Virtual Table 6097** METHOD: sqlite3 6098** 6099** ^(Virtual tables can provide alternative implementations of functions 6100** using the [xFindFunction] method of the [virtual table module]. 6101** But global versions of those functions 6102** must exist in order to be overloaded.)^ 6103** 6104** ^(This API makes sure a global version of a function with a particular 6105** name and number of parameters exists. If no such function exists 6106** before this API is called, a new function is created.)^ ^The implementation 6107** of the new function always causes an exception to be thrown. So 6108** the new function is not good for anything by itself. Its only 6109** purpose is to be a placeholder function that can be overloaded 6110** by a [virtual table]. 6111*/ 6112int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 6113 6114/* 6115** The interface to the virtual-table mechanism defined above (back up 6116** to a comment remarkably similar to this one) is currently considered 6117** to be experimental. The interface might change in incompatible ways. 6118** If this is a problem for you, do not use the interface at this time. 6119** 6120** When the virtual-table mechanism stabilizes, we will declare the 6121** interface fixed, support it indefinitely, and remove this comment. 6122*/ 6123 6124/* 6125** CAPI3REF: A Handle To An Open BLOB 6126** KEYWORDS: {BLOB handle} {BLOB handles} 6127** 6128** An instance of this object represents an open BLOB on which 6129** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 6130** ^Objects of this type are created by [sqlite3_blob_open()] 6131** and destroyed by [sqlite3_blob_close()]. 6132** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 6133** can be used to read or write small subsections of the BLOB. 6134** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 6135*/ 6136typedef struct sqlite3_blob sqlite3_blob; 6137 6138/* 6139** CAPI3REF: Open A BLOB For Incremental I/O 6140** METHOD: sqlite3 6141** CONSTRUCTOR: sqlite3_blob 6142** 6143** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 6144** in row iRow, column zColumn, table zTable in database zDb; 6145** in other words, the same BLOB that would be selected by: 6146** 6147** <pre> 6148** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 6149** </pre>)^ 6150** 6151** ^(Parameter zDb is not the filename that contains the database, but 6152** rather the symbolic name of the database. For attached databases, this is 6153** the name that appears after the AS keyword in the [ATTACH] statement. 6154** For the main database file, the database name is "main". For TEMP 6155** tables, the database name is "temp".)^ 6156** 6157** ^If the flags parameter is non-zero, then the BLOB is opened for read 6158** and write access. ^If the flags parameter is zero, the BLOB is opened for 6159** read-only access. 6160** 6161** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 6162** in *ppBlob. Otherwise an [error code] is returned and, unless the error 6163** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 6164** the API is not misused, it is always safe to call [sqlite3_blob_close()] 6165** on *ppBlob after this function it returns. 6166** 6167** This function fails with SQLITE_ERROR if any of the following are true: 6168** <ul> 6169** <li> ^(Database zDb does not exist)^, 6170** <li> ^(Table zTable does not exist within database zDb)^, 6171** <li> ^(Table zTable is a WITHOUT ROWID table)^, 6172** <li> ^(Column zColumn does not exist)^, 6173** <li> ^(Row iRow is not present in the table)^, 6174** <li> ^(The specified column of row iRow contains a value that is not 6175** a TEXT or BLOB value)^, 6176** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 6177** constraint and the blob is being opened for read/write access)^, 6178** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 6179** column zColumn is part of a [child key] definition and the blob is 6180** being opened for read/write access)^. 6181** </ul> 6182** 6183** ^Unless it returns SQLITE_MISUSE, this function sets the 6184** [database connection] error code and message accessible via 6185** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6186** 6187** 6188** ^(If the row that a BLOB handle points to is modified by an 6189** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 6190** then the BLOB handle is marked as "expired". 6191** This is true if any column of the row is changed, even a column 6192** other than the one the BLOB handle is open on.)^ 6193** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 6194** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 6195** ^(Changes written into a BLOB prior to the BLOB expiring are not 6196** rolled back by the expiration of the BLOB. Such changes will eventually 6197** commit if the transaction continues to completion.)^ 6198** 6199** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 6200** the opened blob. ^The size of a blob may not be changed by this 6201** interface. Use the [UPDATE] SQL command to change the size of a 6202** blob. 6203** 6204** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 6205** and the built-in [zeroblob] SQL function may be used to create a 6206** zero-filled blob to read or write using the incremental-blob interface. 6207** 6208** To avoid a resource leak, every open [BLOB handle] should eventually 6209** be released by a call to [sqlite3_blob_close()]. 6210*/ 6211int sqlite3_blob_open( 6212 sqlite3*, 6213 const char *zDb, 6214 const char *zTable, 6215 const char *zColumn, 6216 sqlite3_int64 iRow, 6217 int flags, 6218 sqlite3_blob **ppBlob 6219); 6220 6221/* 6222** CAPI3REF: Move a BLOB Handle to a New Row 6223** METHOD: sqlite3_blob 6224** 6225** ^This function is used to move an existing blob handle so that it points 6226** to a different row of the same database table. ^The new row is identified 6227** by the rowid value passed as the second argument. Only the row can be 6228** changed. ^The database, table and column on which the blob handle is open 6229** remain the same. Moving an existing blob handle to a new row can be 6230** faster than closing the existing handle and opening a new one. 6231** 6232** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 6233** it must exist and there must be either a blob or text value stored in 6234** the nominated column.)^ ^If the new row is not present in the table, or if 6235** it does not contain a blob or text value, or if another error occurs, an 6236** SQLite error code is returned and the blob handle is considered aborted. 6237** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 6238** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 6239** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 6240** always returns zero. 6241** 6242** ^This function sets the database handle error code and message. 6243*/ 6244int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 6245 6246/* 6247** CAPI3REF: Close A BLOB Handle 6248** DESTRUCTOR: sqlite3_blob 6249** 6250** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 6251** unconditionally. Even if this routine returns an error code, the 6252** handle is still closed.)^ 6253** 6254** ^If the blob handle being closed was opened for read-write access, and if 6255** the database is in auto-commit mode and there are no other open read-write 6256** blob handles or active write statements, the current transaction is 6257** committed. ^If an error occurs while committing the transaction, an error 6258** code is returned and the transaction rolled back. 6259** 6260** Calling this function with an argument that is not a NULL pointer or an 6261** open blob handle results in undefined behaviour. ^Calling this routine 6262** with a null pointer (such as would be returned by a failed call to 6263** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 6264** is passed a valid open blob handle, the values returned by the 6265** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 6266*/ 6267int sqlite3_blob_close(sqlite3_blob *); 6268 6269/* 6270** CAPI3REF: Return The Size Of An Open BLOB 6271** METHOD: sqlite3_blob 6272** 6273** ^Returns the size in bytes of the BLOB accessible via the 6274** successfully opened [BLOB handle] in its only argument. ^The 6275** incremental blob I/O routines can only read or overwriting existing 6276** blob content; they cannot change the size of a blob. 6277** 6278** This routine only works on a [BLOB handle] which has been created 6279** by a prior successful call to [sqlite3_blob_open()] and which has not 6280** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6281** to this routine results in undefined and probably undesirable behavior. 6282*/ 6283int sqlite3_blob_bytes(sqlite3_blob *); 6284 6285/* 6286** CAPI3REF: Read Data From A BLOB Incrementally 6287** METHOD: sqlite3_blob 6288** 6289** ^(This function is used to read data from an open [BLOB handle] into a 6290** caller-supplied buffer. N bytes of data are copied into buffer Z 6291** from the open BLOB, starting at offset iOffset.)^ 6292** 6293** ^If offset iOffset is less than N bytes from the end of the BLOB, 6294** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6295** less than zero, [SQLITE_ERROR] is returned and no data is read. 6296** ^The size of the blob (and hence the maximum value of N+iOffset) 6297** can be determined using the [sqlite3_blob_bytes()] interface. 6298** 6299** ^An attempt to read from an expired [BLOB handle] fails with an 6300** error code of [SQLITE_ABORT]. 6301** 6302** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6303** Otherwise, an [error code] or an [extended error code] is returned.)^ 6304** 6305** This routine only works on a [BLOB handle] which has been created 6306** by a prior successful call to [sqlite3_blob_open()] and which has not 6307** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6308** to this routine results in undefined and probably undesirable behavior. 6309** 6310** See also: [sqlite3_blob_write()]. 6311*/ 6312int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6313 6314/* 6315** CAPI3REF: Write Data Into A BLOB Incrementally 6316** METHOD: sqlite3_blob 6317** 6318** ^(This function is used to write data into an open [BLOB handle] from a 6319** caller-supplied buffer. N bytes of data are copied from the buffer Z 6320** into the open BLOB, starting at offset iOffset.)^ 6321** 6322** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6323** Otherwise, an [error code] or an [extended error code] is returned.)^ 6324** ^Unless SQLITE_MISUSE is returned, this function sets the 6325** [database connection] error code and message accessible via 6326** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6327** 6328** ^If the [BLOB handle] passed as the first argument was not opened for 6329** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6330** this function returns [SQLITE_READONLY]. 6331** 6332** This function may only modify the contents of the BLOB; it is 6333** not possible to increase the size of a BLOB using this API. 6334** ^If offset iOffset is less than N bytes from the end of the BLOB, 6335** [SQLITE_ERROR] is returned and no data is written. The size of the 6336** BLOB (and hence the maximum value of N+iOffset) can be determined 6337** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6338** than zero [SQLITE_ERROR] is returned and no data is written. 6339** 6340** ^An attempt to write to an expired [BLOB handle] fails with an 6341** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6342** before the [BLOB handle] expired are not rolled back by the 6343** expiration of the handle, though of course those changes might 6344** have been overwritten by the statement that expired the BLOB handle 6345** or by other independent statements. 6346** 6347** This routine only works on a [BLOB handle] which has been created 6348** by a prior successful call to [sqlite3_blob_open()] and which has not 6349** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6350** to this routine results in undefined and probably undesirable behavior. 6351** 6352** See also: [sqlite3_blob_read()]. 6353*/ 6354int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6355 6356/* 6357** CAPI3REF: Virtual File System Objects 6358** 6359** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6360** that SQLite uses to interact 6361** with the underlying operating system. Most SQLite builds come with a 6362** single default VFS that is appropriate for the host computer. 6363** New VFSes can be registered and existing VFSes can be unregistered. 6364** The following interfaces are provided. 6365** 6366** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6367** ^Names are case sensitive. 6368** ^Names are zero-terminated UTF-8 strings. 6369** ^If there is no match, a NULL pointer is returned. 6370** ^If zVfsName is NULL then the default VFS is returned. 6371** 6372** ^New VFSes are registered with sqlite3_vfs_register(). 6373** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6374** ^The same VFS can be registered multiple times without injury. 6375** ^To make an existing VFS into the default VFS, register it again 6376** with the makeDflt flag set. If two different VFSes with the 6377** same name are registered, the behavior is undefined. If a 6378** VFS is registered with a name that is NULL or an empty string, 6379** then the behavior is undefined. 6380** 6381** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6382** ^(If the default VFS is unregistered, another VFS is chosen as 6383** the default. The choice for the new VFS is arbitrary.)^ 6384*/ 6385sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6386int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6387int sqlite3_vfs_unregister(sqlite3_vfs*); 6388 6389/* 6390** CAPI3REF: Mutexes 6391** 6392** The SQLite core uses these routines for thread 6393** synchronization. Though they are intended for internal 6394** use by SQLite, code that links against SQLite is 6395** permitted to use any of these routines. 6396** 6397** The SQLite source code contains multiple implementations 6398** of these mutex routines. An appropriate implementation 6399** is selected automatically at compile-time. The following 6400** implementations are available in the SQLite core: 6401** 6402** <ul> 6403** <li> SQLITE_MUTEX_PTHREADS 6404** <li> SQLITE_MUTEX_W32 6405** <li> SQLITE_MUTEX_NOOP 6406** </ul> 6407** 6408** The SQLITE_MUTEX_NOOP implementation is a set of routines 6409** that does no real locking and is appropriate for use in 6410** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6411** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6412** and Windows. 6413** 6414** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6415** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6416** implementation is included with the library. In this case the 6417** application must supply a custom mutex implementation using the 6418** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6419** before calling sqlite3_initialize() or any other public sqlite3_ 6420** function that calls sqlite3_initialize(). 6421** 6422** ^The sqlite3_mutex_alloc() routine allocates a new 6423** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6424** routine returns NULL if it is unable to allocate the requested 6425** mutex. The argument to sqlite3_mutex_alloc() must one of these 6426** integer constants: 6427** 6428** <ul> 6429** <li> SQLITE_MUTEX_FAST 6430** <li> SQLITE_MUTEX_RECURSIVE 6431** <li> SQLITE_MUTEX_STATIC_MASTER 6432** <li> SQLITE_MUTEX_STATIC_MEM 6433** <li> SQLITE_MUTEX_STATIC_OPEN 6434** <li> SQLITE_MUTEX_STATIC_PRNG 6435** <li> SQLITE_MUTEX_STATIC_LRU 6436** <li> SQLITE_MUTEX_STATIC_PMEM 6437** <li> SQLITE_MUTEX_STATIC_APP1 6438** <li> SQLITE_MUTEX_STATIC_APP2 6439** <li> SQLITE_MUTEX_STATIC_APP3 6440** <li> SQLITE_MUTEX_STATIC_VFS1 6441** <li> SQLITE_MUTEX_STATIC_VFS2 6442** <li> SQLITE_MUTEX_STATIC_VFS3 6443** </ul> 6444** 6445** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6446** cause sqlite3_mutex_alloc() to create 6447** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6448** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6449** The mutex implementation does not need to make a distinction 6450** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6451** not want to. SQLite will only request a recursive mutex in 6452** cases where it really needs one. If a faster non-recursive mutex 6453** implementation is available on the host platform, the mutex subsystem 6454** might return such a mutex in response to SQLITE_MUTEX_FAST. 6455** 6456** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6457** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6458** a pointer to a static preexisting mutex. ^Nine static mutexes are 6459** used by the current version of SQLite. Future versions of SQLite 6460** may add additional static mutexes. Static mutexes are for internal 6461** use by SQLite only. Applications that use SQLite mutexes should 6462** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6463** SQLITE_MUTEX_RECURSIVE. 6464** 6465** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6466** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6467** returns a different mutex on every call. ^For the static 6468** mutex types, the same mutex is returned on every call that has 6469** the same type number. 6470** 6471** ^The sqlite3_mutex_free() routine deallocates a previously 6472** allocated dynamic mutex. Attempting to deallocate a static 6473** mutex results in undefined behavior. 6474** 6475** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6476** to enter a mutex. ^If another thread is already within the mutex, 6477** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6478** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6479** upon successful entry. ^(Mutexes created using 6480** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6481** In such cases, the 6482** mutex must be exited an equal number of times before another thread 6483** can enter.)^ If the same thread tries to enter any mutex other 6484** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6485** 6486** ^(Some systems (for example, Windows 95) do not support the operation 6487** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6488** will always return SQLITE_BUSY. The SQLite core only ever uses 6489** sqlite3_mutex_try() as an optimization so this is acceptable 6490** behavior.)^ 6491** 6492** ^The sqlite3_mutex_leave() routine exits a mutex that was 6493** previously entered by the same thread. The behavior 6494** is undefined if the mutex is not currently entered by the 6495** calling thread or is not currently allocated. 6496** 6497** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6498** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6499** behave as no-ops. 6500** 6501** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6502*/ 6503sqlite3_mutex *sqlite3_mutex_alloc(int); 6504void sqlite3_mutex_free(sqlite3_mutex*); 6505void sqlite3_mutex_enter(sqlite3_mutex*); 6506int sqlite3_mutex_try(sqlite3_mutex*); 6507void sqlite3_mutex_leave(sqlite3_mutex*); 6508 6509/* 6510** CAPI3REF: Mutex Methods Object 6511** 6512** An instance of this structure defines the low-level routines 6513** used to allocate and use mutexes. 6514** 6515** Usually, the default mutex implementations provided by SQLite are 6516** sufficient, however the application has the option of substituting a custom 6517** implementation for specialized deployments or systems for which SQLite 6518** does not provide a suitable implementation. In this case, the application 6519** creates and populates an instance of this structure to pass 6520** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6521** Additionally, an instance of this structure can be used as an 6522** output variable when querying the system for the current mutex 6523** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6524** 6525** ^The xMutexInit method defined by this structure is invoked as 6526** part of system initialization by the sqlite3_initialize() function. 6527** ^The xMutexInit routine is called by SQLite exactly once for each 6528** effective call to [sqlite3_initialize()]. 6529** 6530** ^The xMutexEnd method defined by this structure is invoked as 6531** part of system shutdown by the sqlite3_shutdown() function. The 6532** implementation of this method is expected to release all outstanding 6533** resources obtained by the mutex methods implementation, especially 6534** those obtained by the xMutexInit method. ^The xMutexEnd() 6535** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6536** 6537** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6538** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6539** xMutexNotheld) implement the following interfaces (respectively): 6540** 6541** <ul> 6542** <li> [sqlite3_mutex_alloc()] </li> 6543** <li> [sqlite3_mutex_free()] </li> 6544** <li> [sqlite3_mutex_enter()] </li> 6545** <li> [sqlite3_mutex_try()] </li> 6546** <li> [sqlite3_mutex_leave()] </li> 6547** <li> [sqlite3_mutex_held()] </li> 6548** <li> [sqlite3_mutex_notheld()] </li> 6549** </ul>)^ 6550** 6551** The only difference is that the public sqlite3_XXX functions enumerated 6552** above silently ignore any invocations that pass a NULL pointer instead 6553** of a valid mutex handle. The implementations of the methods defined 6554** by this structure are not required to handle this case, the results 6555** of passing a NULL pointer instead of a valid mutex handle are undefined 6556** (i.e. it is acceptable to provide an implementation that segfaults if 6557** it is passed a NULL pointer). 6558** 6559** The xMutexInit() method must be threadsafe. It must be harmless to 6560** invoke xMutexInit() multiple times within the same process and without 6561** intervening calls to xMutexEnd(). Second and subsequent calls to 6562** xMutexInit() must be no-ops. 6563** 6564** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6565** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6566** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6567** memory allocation for a fast or recursive mutex. 6568** 6569** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6570** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6571** If xMutexInit fails in any way, it is expected to clean up after itself 6572** prior to returning. 6573*/ 6574typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6575struct sqlite3_mutex_methods { 6576 int (*xMutexInit)(void); 6577 int (*xMutexEnd)(void); 6578 sqlite3_mutex *(*xMutexAlloc)(int); 6579 void (*xMutexFree)(sqlite3_mutex *); 6580 void (*xMutexEnter)(sqlite3_mutex *); 6581 int (*xMutexTry)(sqlite3_mutex *); 6582 void (*xMutexLeave)(sqlite3_mutex *); 6583 int (*xMutexHeld)(sqlite3_mutex *); 6584 int (*xMutexNotheld)(sqlite3_mutex *); 6585}; 6586 6587/* 6588** CAPI3REF: Mutex Verification Routines 6589** 6590** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6591** are intended for use inside assert() statements. The SQLite core 6592** never uses these routines except inside an assert() and applications 6593** are advised to follow the lead of the core. The SQLite core only 6594** provides implementations for these routines when it is compiled 6595** with the SQLITE_DEBUG flag. External mutex implementations 6596** are only required to provide these routines if SQLITE_DEBUG is 6597** defined and if NDEBUG is not defined. 6598** 6599** These routines should return true if the mutex in their argument 6600** is held or not held, respectively, by the calling thread. 6601** 6602** The implementation is not required to provide versions of these 6603** routines that actually work. If the implementation does not provide working 6604** versions of these routines, it should at least provide stubs that always 6605** return true so that one does not get spurious assertion failures. 6606** 6607** If the argument to sqlite3_mutex_held() is a NULL pointer then 6608** the routine should return 1. This seems counter-intuitive since 6609** clearly the mutex cannot be held if it does not exist. But 6610** the reason the mutex does not exist is because the build is not 6611** using mutexes. And we do not want the assert() containing the 6612** call to sqlite3_mutex_held() to fail, so a non-zero return is 6613** the appropriate thing to do. The sqlite3_mutex_notheld() 6614** interface should also return 1 when given a NULL pointer. 6615*/ 6616#ifndef NDEBUG 6617int sqlite3_mutex_held(sqlite3_mutex*); 6618int sqlite3_mutex_notheld(sqlite3_mutex*); 6619#endif 6620 6621/* 6622** CAPI3REF: Mutex Types 6623** 6624** The [sqlite3_mutex_alloc()] interface takes a single argument 6625** which is one of these integer constants. 6626** 6627** The set of static mutexes may change from one SQLite release to the 6628** next. Applications that override the built-in mutex logic must be 6629** prepared to accommodate additional static mutexes. 6630*/ 6631#define SQLITE_MUTEX_FAST 0 6632#define SQLITE_MUTEX_RECURSIVE 1 6633#define SQLITE_MUTEX_STATIC_MASTER 2 6634#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6635#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6636#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6637#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 6638#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6639#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6640#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6641#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6642#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6643#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6644#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 6645#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 6646#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 6647 6648/* 6649** CAPI3REF: Retrieve the mutex for a database connection 6650** METHOD: sqlite3 6651** 6652** ^This interface returns a pointer the [sqlite3_mutex] object that 6653** serializes access to the [database connection] given in the argument 6654** when the [threading mode] is Serialized. 6655** ^If the [threading mode] is Single-thread or Multi-thread then this 6656** routine returns a NULL pointer. 6657*/ 6658sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 6659 6660/* 6661** CAPI3REF: Low-Level Control Of Database Files 6662** METHOD: sqlite3 6663** 6664** ^The [sqlite3_file_control()] interface makes a direct call to the 6665** xFileControl method for the [sqlite3_io_methods] object associated 6666** with a particular database identified by the second argument. ^The 6667** name of the database is "main" for the main database or "temp" for the 6668** TEMP database, or the name that appears after the AS keyword for 6669** databases that are added using the [ATTACH] SQL command. 6670** ^A NULL pointer can be used in place of "main" to refer to the 6671** main database file. 6672** ^The third and fourth parameters to this routine 6673** are passed directly through to the second and third parameters of 6674** the xFileControl method. ^The return value of the xFileControl 6675** method becomes the return value of this routine. 6676** 6677** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 6678** a pointer to the underlying [sqlite3_file] object to be written into 6679** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 6680** case is a short-circuit path which does not actually invoke the 6681** underlying sqlite3_io_methods.xFileControl method. 6682** 6683** ^If the second parameter (zDbName) does not match the name of any 6684** open database file, then SQLITE_ERROR is returned. ^This error 6685** code is not remembered and will not be recalled by [sqlite3_errcode()] 6686** or [sqlite3_errmsg()]. The underlying xFileControl method might 6687** also return SQLITE_ERROR. There is no way to distinguish between 6688** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6689** xFileControl method. 6690** 6691** See also: [SQLITE_FCNTL_LOCKSTATE] 6692*/ 6693int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6694 6695/* 6696** CAPI3REF: Testing Interface 6697** 6698** ^The sqlite3_test_control() interface is used to read out internal 6699** state of SQLite and to inject faults into SQLite for testing 6700** purposes. ^The first parameter is an operation code that determines 6701** the number, meaning, and operation of all subsequent parameters. 6702** 6703** This interface is not for use by applications. It exists solely 6704** for verifying the correct operation of the SQLite library. Depending 6705** on how the SQLite library is compiled, this interface might not exist. 6706** 6707** The details of the operation codes, their meanings, the parameters 6708** they take, and what they do are all subject to change without notice. 6709** Unlike most of the SQLite API, this function is not guaranteed to 6710** operate consistently from one release to the next. 6711*/ 6712int sqlite3_test_control(int op, ...); 6713 6714/* 6715** CAPI3REF: Testing Interface Operation Codes 6716** 6717** These constants are the valid operation code parameters used 6718** as the first argument to [sqlite3_test_control()]. 6719** 6720** These parameters and their meanings are subject to change 6721** without notice. These values are for testing purposes only. 6722** Applications should not use any of these parameters or the 6723** [sqlite3_test_control()] interface. 6724*/ 6725#define SQLITE_TESTCTRL_FIRST 5 6726#define SQLITE_TESTCTRL_PRNG_SAVE 5 6727#define SQLITE_TESTCTRL_PRNG_RESTORE 6 6728#define SQLITE_TESTCTRL_PRNG_RESET 7 6729#define SQLITE_TESTCTRL_BITVEC_TEST 8 6730#define SQLITE_TESTCTRL_FAULT_INSTALL 9 6731#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 6732#define SQLITE_TESTCTRL_PENDING_BYTE 11 6733#define SQLITE_TESTCTRL_ASSERT 12 6734#define SQLITE_TESTCTRL_ALWAYS 13 6735#define SQLITE_TESTCTRL_RESERVE 14 6736#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 6737#define SQLITE_TESTCTRL_ISKEYWORD 16 6738#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 6739#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 6740#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 6741#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 6742#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 6743#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 6744#define SQLITE_TESTCTRL_BYTEORDER 22 6745#define SQLITE_TESTCTRL_ISINIT 23 6746#define SQLITE_TESTCTRL_SORTER_MMAP 24 6747#define SQLITE_TESTCTRL_IMPOSTER 25 6748#define SQLITE_TESTCTRL_LAST 25 6749 6750/* 6751** CAPI3REF: SQLite Runtime Status 6752** 6753** ^These interfaces are used to retrieve runtime status information 6754** about the performance of SQLite, and optionally to reset various 6755** highwater marks. ^The first argument is an integer code for 6756** the specific parameter to measure. ^(Recognized integer codes 6757** are of the form [status parameters | SQLITE_STATUS_...].)^ 6758** ^The current value of the parameter is returned into *pCurrent. 6759** ^The highest recorded value is returned in *pHighwater. ^If the 6760** resetFlag is true, then the highest record value is reset after 6761** *pHighwater is written. ^(Some parameters do not record the highest 6762** value. For those parameters 6763** nothing is written into *pHighwater and the resetFlag is ignored.)^ 6764** ^(Other parameters record only the highwater mark and not the current 6765** value. For these latter parameters nothing is written into *pCurrent.)^ 6766** 6767** ^The sqlite3_status() and sqlite3_status64() routines return 6768** SQLITE_OK on success and a non-zero [error code] on failure. 6769** 6770** If either the current value or the highwater mark is too large to 6771** be represented by a 32-bit integer, then the values returned by 6772** sqlite3_status() are undefined. 6773** 6774** See also: [sqlite3_db_status()] 6775*/ 6776int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 6777int sqlite3_status64( 6778 int op, 6779 sqlite3_int64 *pCurrent, 6780 sqlite3_int64 *pHighwater, 6781 int resetFlag 6782); 6783 6784 6785/* 6786** CAPI3REF: Status Parameters 6787** KEYWORDS: {status parameters} 6788** 6789** These integer constants designate various run-time status parameters 6790** that can be returned by [sqlite3_status()]. 6791** 6792** <dl> 6793** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 6794** <dd>This parameter is the current amount of memory checked out 6795** using [sqlite3_malloc()], either directly or indirectly. The 6796** figure includes calls made to [sqlite3_malloc()] by the application 6797** and internal memory usage by the SQLite library. Scratch memory 6798** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 6799** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 6800** this parameter. The amount returned is the sum of the allocation 6801** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 6802** 6803** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 6804** <dd>This parameter records the largest memory allocation request 6805** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 6806** internal equivalents). Only the value returned in the 6807** *pHighwater parameter to [sqlite3_status()] is of interest. 6808** The value written into the *pCurrent parameter is undefined.</dd>)^ 6809** 6810** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 6811** <dd>This parameter records the number of separate memory allocations 6812** currently checked out.</dd>)^ 6813** 6814** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 6815** <dd>This parameter returns the number of pages used out of the 6816** [pagecache memory allocator] that was configured using 6817** [SQLITE_CONFIG_PAGECACHE]. The 6818** value returned is in pages, not in bytes.</dd>)^ 6819** 6820** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 6821** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 6822** <dd>This parameter returns the number of bytes of page cache 6823** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 6824** buffer and where forced to overflow to [sqlite3_malloc()]. The 6825** returned value includes allocations that overflowed because they 6826** where too large (they were larger than the "sz" parameter to 6827** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 6828** no space was left in the page cache.</dd>)^ 6829** 6830** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 6831** <dd>This parameter records the largest memory allocation request 6832** handed to [pagecache memory allocator]. Only the value returned in the 6833** *pHighwater parameter to [sqlite3_status()] is of interest. 6834** The value written into the *pCurrent parameter is undefined.</dd>)^ 6835** 6836** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 6837** <dd>This parameter returns the number of allocations used out of the 6838** [scratch memory allocator] configured using 6839** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 6840** in bytes. Since a single thread may only have one scratch allocation 6841** outstanding at time, this parameter also reports the number of threads 6842** using scratch memory at the same time.</dd>)^ 6843** 6844** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 6845** <dd>This parameter returns the number of bytes of scratch memory 6846** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 6847** buffer and where forced to overflow to [sqlite3_malloc()]. The values 6848** returned include overflows because the requested allocation was too 6849** larger (that is, because the requested allocation was larger than the 6850** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 6851** slots were available. 6852** </dd>)^ 6853** 6854** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 6855** <dd>This parameter records the largest memory allocation request 6856** handed to [scratch memory allocator]. Only the value returned in the 6857** *pHighwater parameter to [sqlite3_status()] is of interest. 6858** The value written into the *pCurrent parameter is undefined.</dd>)^ 6859** 6860** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 6861** <dd>The *pHighwater parameter records the deepest parser stack. 6862** The *pCurrent value is undefined. The *pHighwater value is only 6863** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 6864** </dl> 6865** 6866** New status parameters may be added from time to time. 6867*/ 6868#define SQLITE_STATUS_MEMORY_USED 0 6869#define SQLITE_STATUS_PAGECACHE_USED 1 6870#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 6871#define SQLITE_STATUS_SCRATCH_USED 3 6872#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 6873#define SQLITE_STATUS_MALLOC_SIZE 5 6874#define SQLITE_STATUS_PARSER_STACK 6 6875#define SQLITE_STATUS_PAGECACHE_SIZE 7 6876#define SQLITE_STATUS_SCRATCH_SIZE 8 6877#define SQLITE_STATUS_MALLOC_COUNT 9 6878 6879/* 6880** CAPI3REF: Database Connection Status 6881** METHOD: sqlite3 6882** 6883** ^This interface is used to retrieve runtime status information 6884** about a single [database connection]. ^The first argument is the 6885** database connection object to be interrogated. ^The second argument 6886** is an integer constant, taken from the set of 6887** [SQLITE_DBSTATUS options], that 6888** determines the parameter to interrogate. The set of 6889** [SQLITE_DBSTATUS options] is likely 6890** to grow in future releases of SQLite. 6891** 6892** ^The current value of the requested parameter is written into *pCur 6893** and the highest instantaneous value is written into *pHiwtr. ^If 6894** the resetFlg is true, then the highest instantaneous value is 6895** reset back down to the current value. 6896** 6897** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 6898** non-zero [error code] on failure. 6899** 6900** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 6901*/ 6902int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 6903 6904/* 6905** CAPI3REF: Status Parameters for database connections 6906** KEYWORDS: {SQLITE_DBSTATUS options} 6907** 6908** These constants are the available integer "verbs" that can be passed as 6909** the second argument to the [sqlite3_db_status()] interface. 6910** 6911** New verbs may be added in future releases of SQLite. Existing verbs 6912** might be discontinued. Applications should check the return code from 6913** [sqlite3_db_status()] to make sure that the call worked. 6914** The [sqlite3_db_status()] interface will return a non-zero error code 6915** if a discontinued or unsupported verb is invoked. 6916** 6917** <dl> 6918** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 6919** <dd>This parameter returns the number of lookaside memory slots currently 6920** checked out.</dd>)^ 6921** 6922** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 6923** <dd>This parameter returns the number malloc attempts that were 6924** satisfied using lookaside memory. Only the high-water value is meaningful; 6925** the current value is always zero.)^ 6926** 6927** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 6928** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 6929** <dd>This parameter returns the number malloc attempts that might have 6930** been satisfied using lookaside memory but failed due to the amount of 6931** memory requested being larger than the lookaside slot size. 6932** Only the high-water value is meaningful; 6933** the current value is always zero.)^ 6934** 6935** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 6936** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 6937** <dd>This parameter returns the number malloc attempts that might have 6938** been satisfied using lookaside memory but failed due to all lookaside 6939** memory already being in use. 6940** Only the high-water value is meaningful; 6941** the current value is always zero.)^ 6942** 6943** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 6944** <dd>This parameter returns the approximate number of bytes of heap 6945** memory used by all pager caches associated with the database connection.)^ 6946** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 6947** 6948** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 6949** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 6950** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 6951** pager cache is shared between two or more connections the bytes of heap 6952** memory used by that pager cache is divided evenly between the attached 6953** connections.)^ In other words, if none of the pager caches associated 6954** with the database connection are shared, this request returns the same 6955** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 6956** shared, the value returned by this call will be smaller than that returned 6957** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 6958** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 6959** 6960** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 6961** <dd>This parameter returns the approximate number of bytes of heap 6962** memory used to store the schema for all databases associated 6963** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 6964** ^The full amount of memory used by the schemas is reported, even if the 6965** schema memory is shared with other database connections due to 6966** [shared cache mode] being enabled. 6967** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 6968** 6969** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 6970** <dd>This parameter returns the approximate number of bytes of heap 6971** and lookaside memory used by all prepared statements associated with 6972** the database connection.)^ 6973** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 6974** </dd> 6975** 6976** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 6977** <dd>This parameter returns the number of pager cache hits that have 6978** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 6979** is always 0. 6980** </dd> 6981** 6982** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6983** <dd>This parameter returns the number of pager cache misses that have 6984** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6985** is always 0. 6986** </dd> 6987** 6988** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 6989** <dd>This parameter returns the number of dirty cache entries that have 6990** been written to disk. Specifically, the number of pages written to the 6991** wal file in wal mode databases, or the number of pages written to the 6992** database file in rollback mode databases. Any pages written as part of 6993** transaction rollback or database recovery operations are not included. 6994** If an IO or other error occurs while writing a page to disk, the effect 6995** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 6996** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 6997** </dd> 6998** 6999** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 7000** <dd>This parameter returns zero for the current value if and only if 7001** all foreign key constraints (deferred or immediate) have been 7002** resolved.)^ ^The highwater mark is always 0. 7003** </dd> 7004** </dl> 7005*/ 7006#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 7007#define SQLITE_DBSTATUS_CACHE_USED 1 7008#define SQLITE_DBSTATUS_SCHEMA_USED 2 7009#define SQLITE_DBSTATUS_STMT_USED 3 7010#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 7011#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 7012#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 7013#define SQLITE_DBSTATUS_CACHE_HIT 7 7014#define SQLITE_DBSTATUS_CACHE_MISS 8 7015#define SQLITE_DBSTATUS_CACHE_WRITE 9 7016#define SQLITE_DBSTATUS_DEFERRED_FKS 10 7017#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 7018#define SQLITE_DBSTATUS_MAX 11 /* Largest defined DBSTATUS */ 7019 7020 7021/* 7022** CAPI3REF: Prepared Statement Status 7023** METHOD: sqlite3_stmt 7024** 7025** ^(Each prepared statement maintains various 7026** [SQLITE_STMTSTATUS counters] that measure the number 7027** of times it has performed specific operations.)^ These counters can 7028** be used to monitor the performance characteristics of the prepared 7029** statements. For example, if the number of table steps greatly exceeds 7030** the number of table searches or result rows, that would tend to indicate 7031** that the prepared statement is using a full table scan rather than 7032** an index. 7033** 7034** ^(This interface is used to retrieve and reset counter values from 7035** a [prepared statement]. The first argument is the prepared statement 7036** object to be interrogated. The second argument 7037** is an integer code for a specific [SQLITE_STMTSTATUS counter] 7038** to be interrogated.)^ 7039** ^The current value of the requested counter is returned. 7040** ^If the resetFlg is true, then the counter is reset to zero after this 7041** interface call returns. 7042** 7043** See also: [sqlite3_status()] and [sqlite3_db_status()]. 7044*/ 7045int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 7046 7047/* 7048** CAPI3REF: Status Parameters for prepared statements 7049** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 7050** 7051** These preprocessor macros define integer codes that name counter 7052** values associated with the [sqlite3_stmt_status()] interface. 7053** The meanings of the various counters are as follows: 7054** 7055** <dl> 7056** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 7057** <dd>^This is the number of times that SQLite has stepped forward in 7058** a table as part of a full table scan. Large numbers for this counter 7059** may indicate opportunities for performance improvement through 7060** careful use of indices.</dd> 7061** 7062** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 7063** <dd>^This is the number of sort operations that have occurred. 7064** A non-zero value in this counter may indicate an opportunity to 7065** improvement performance through careful use of indices.</dd> 7066** 7067** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 7068** <dd>^This is the number of rows inserted into transient indices that 7069** were created automatically in order to help joins run faster. 7070** A non-zero value in this counter may indicate an opportunity to 7071** improvement performance by adding permanent indices that do not 7072** need to be reinitialized each time the statement is run.</dd> 7073** 7074** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 7075** <dd>^This is the number of virtual machine operations executed 7076** by the prepared statement if that number is less than or equal 7077** to 2147483647. The number of virtual machine operations can be 7078** used as a proxy for the total work done by the prepared statement. 7079** If the number of virtual machine operations exceeds 2147483647 7080** then the value returned by this statement status code is undefined. 7081** </dd> 7082** </dl> 7083*/ 7084#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 7085#define SQLITE_STMTSTATUS_SORT 2 7086#define SQLITE_STMTSTATUS_AUTOINDEX 3 7087#define SQLITE_STMTSTATUS_VM_STEP 4 7088 7089/* 7090** CAPI3REF: Custom Page Cache Object 7091** 7092** The sqlite3_pcache type is opaque. It is implemented by 7093** the pluggable module. The SQLite core has no knowledge of 7094** its size or internal structure and never deals with the 7095** sqlite3_pcache object except by holding and passing pointers 7096** to the object. 7097** 7098** See [sqlite3_pcache_methods2] for additional information. 7099*/ 7100typedef struct sqlite3_pcache sqlite3_pcache; 7101 7102/* 7103** CAPI3REF: Custom Page Cache Object 7104** 7105** The sqlite3_pcache_page object represents a single page in the 7106** page cache. The page cache will allocate instances of this 7107** object. Various methods of the page cache use pointers to instances 7108** of this object as parameters or as their return value. 7109** 7110** See [sqlite3_pcache_methods2] for additional information. 7111*/ 7112typedef struct sqlite3_pcache_page sqlite3_pcache_page; 7113struct sqlite3_pcache_page { 7114 void *pBuf; /* The content of the page */ 7115 void *pExtra; /* Extra information associated with the page */ 7116}; 7117 7118/* 7119** CAPI3REF: Application Defined Page Cache. 7120** KEYWORDS: {page cache} 7121** 7122** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 7123** register an alternative page cache implementation by passing in an 7124** instance of the sqlite3_pcache_methods2 structure.)^ 7125** In many applications, most of the heap memory allocated by 7126** SQLite is used for the page cache. 7127** By implementing a 7128** custom page cache using this API, an application can better control 7129** the amount of memory consumed by SQLite, the way in which 7130** that memory is allocated and released, and the policies used to 7131** determine exactly which parts of a database file are cached and for 7132** how long. 7133** 7134** The alternative page cache mechanism is an 7135** extreme measure that is only needed by the most demanding applications. 7136** The built-in page cache is recommended for most uses. 7137** 7138** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 7139** internal buffer by SQLite within the call to [sqlite3_config]. Hence 7140** the application may discard the parameter after the call to 7141** [sqlite3_config()] returns.)^ 7142** 7143** [[the xInit() page cache method]] 7144** ^(The xInit() method is called once for each effective 7145** call to [sqlite3_initialize()])^ 7146** (usually only once during the lifetime of the process). ^(The xInit() 7147** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 7148** The intent of the xInit() method is to set up global data structures 7149** required by the custom page cache implementation. 7150** ^(If the xInit() method is NULL, then the 7151** built-in default page cache is used instead of the application defined 7152** page cache.)^ 7153** 7154** [[the xShutdown() page cache method]] 7155** ^The xShutdown() method is called by [sqlite3_shutdown()]. 7156** It can be used to clean up 7157** any outstanding resources before process shutdown, if required. 7158** ^The xShutdown() method may be NULL. 7159** 7160** ^SQLite automatically serializes calls to the xInit method, 7161** so the xInit method need not be threadsafe. ^The 7162** xShutdown method is only called from [sqlite3_shutdown()] so it does 7163** not need to be threadsafe either. All other methods must be threadsafe 7164** in multithreaded applications. 7165** 7166** ^SQLite will never invoke xInit() more than once without an intervening 7167** call to xShutdown(). 7168** 7169** [[the xCreate() page cache methods]] 7170** ^SQLite invokes the xCreate() method to construct a new cache instance. 7171** SQLite will typically create one cache instance for each open database file, 7172** though this is not guaranteed. ^The 7173** first parameter, szPage, is the size in bytes of the pages that must 7174** be allocated by the cache. ^szPage will always a power of two. ^The 7175** second parameter szExtra is a number of bytes of extra storage 7176** associated with each page cache entry. ^The szExtra parameter will 7177** a number less than 250. SQLite will use the 7178** extra szExtra bytes on each page to store metadata about the underlying 7179** database page on disk. The value passed into szExtra depends 7180** on the SQLite version, the target platform, and how SQLite was compiled. 7181** ^The third argument to xCreate(), bPurgeable, is true if the cache being 7182** created will be used to cache database pages of a file stored on disk, or 7183** false if it is used for an in-memory database. The cache implementation 7184** does not have to do anything special based with the value of bPurgeable; 7185** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 7186** never invoke xUnpin() except to deliberately delete a page. 7187** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 7188** false will always have the "discard" flag set to true. 7189** ^Hence, a cache created with bPurgeable false will 7190** never contain any unpinned pages. 7191** 7192** [[the xCachesize() page cache method]] 7193** ^(The xCachesize() method may be called at any time by SQLite to set the 7194** suggested maximum cache-size (number of pages stored by) the cache 7195** instance passed as the first argument. This is the value configured using 7196** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 7197** parameter, the implementation is not required to do anything with this 7198** value; it is advisory only. 7199** 7200** [[the xPagecount() page cache methods]] 7201** The xPagecount() method must return the number of pages currently 7202** stored in the cache, both pinned and unpinned. 7203** 7204** [[the xFetch() page cache methods]] 7205** The xFetch() method locates a page in the cache and returns a pointer to 7206** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 7207** The pBuf element of the returned sqlite3_pcache_page object will be a 7208** pointer to a buffer of szPage bytes used to store the content of a 7209** single database page. The pExtra element of sqlite3_pcache_page will be 7210** a pointer to the szExtra bytes of extra storage that SQLite has requested 7211** for each entry in the page cache. 7212** 7213** The page to be fetched is determined by the key. ^The minimum key value 7214** is 1. After it has been retrieved using xFetch, the page is considered 7215** to be "pinned". 7216** 7217** If the requested page is already in the page cache, then the page cache 7218** implementation must return a pointer to the page buffer with its content 7219** intact. If the requested page is not already in the cache, then the 7220** cache implementation should use the value of the createFlag 7221** parameter to help it determined what action to take: 7222** 7223** <table border=1 width=85% align=center> 7224** <tr><th> createFlag <th> Behavior when page is not already in cache 7225** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 7226** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 7227** Otherwise return NULL. 7228** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 7229** NULL if allocating a new page is effectively impossible. 7230** </table> 7231** 7232** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 7233** will only use a createFlag of 2 after a prior call with a createFlag of 1 7234** failed.)^ In between the to xFetch() calls, SQLite may 7235** attempt to unpin one or more cache pages by spilling the content of 7236** pinned pages to disk and synching the operating system disk cache. 7237** 7238** [[the xUnpin() page cache method]] 7239** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 7240** as its second argument. If the third parameter, discard, is non-zero, 7241** then the page must be evicted from the cache. 7242** ^If the discard parameter is 7243** zero, then the page may be discarded or retained at the discretion of 7244** page cache implementation. ^The page cache implementation 7245** may choose to evict unpinned pages at any time. 7246** 7247** The cache must not perform any reference counting. A single 7248** call to xUnpin() unpins the page regardless of the number of prior calls 7249** to xFetch(). 7250** 7251** [[the xRekey() page cache methods]] 7252** The xRekey() method is used to change the key value associated with the 7253** page passed as the second argument. If the cache 7254** previously contains an entry associated with newKey, it must be 7255** discarded. ^Any prior cache entry associated with newKey is guaranteed not 7256** to be pinned. 7257** 7258** When SQLite calls the xTruncate() method, the cache must discard all 7259** existing cache entries with page numbers (keys) greater than or equal 7260** to the value of the iLimit parameter passed to xTruncate(). If any 7261** of these pages are pinned, they are implicitly unpinned, meaning that 7262** they can be safely discarded. 7263** 7264** [[the xDestroy() page cache method]] 7265** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 7266** All resources associated with the specified cache should be freed. ^After 7267** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 7268** handle invalid, and will not use it with any other sqlite3_pcache_methods2 7269** functions. 7270** 7271** [[the xShrink() page cache method]] 7272** ^SQLite invokes the xShrink() method when it wants the page cache to 7273** free up as much of heap memory as possible. The page cache implementation 7274** is not obligated to free any memory, but well-behaved implementations should 7275** do their best. 7276*/ 7277typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 7278struct sqlite3_pcache_methods2 { 7279 int iVersion; 7280 void *pArg; 7281 int (*xInit)(void*); 7282 void (*xShutdown)(void*); 7283 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 7284 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7285 int (*xPagecount)(sqlite3_pcache*); 7286 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7287 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 7288 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 7289 unsigned oldKey, unsigned newKey); 7290 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7291 void (*xDestroy)(sqlite3_pcache*); 7292 void (*xShrink)(sqlite3_pcache*); 7293}; 7294 7295/* 7296** This is the obsolete pcache_methods object that has now been replaced 7297** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 7298** retained in the header file for backwards compatibility only. 7299*/ 7300typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 7301struct sqlite3_pcache_methods { 7302 void *pArg; 7303 int (*xInit)(void*); 7304 void (*xShutdown)(void*); 7305 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 7306 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7307 int (*xPagecount)(sqlite3_pcache*); 7308 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7309 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 7310 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 7311 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7312 void (*xDestroy)(sqlite3_pcache*); 7313}; 7314 7315 7316/* 7317** CAPI3REF: Online Backup Object 7318** 7319** The sqlite3_backup object records state information about an ongoing 7320** online backup operation. ^The sqlite3_backup object is created by 7321** a call to [sqlite3_backup_init()] and is destroyed by a call to 7322** [sqlite3_backup_finish()]. 7323** 7324** See Also: [Using the SQLite Online Backup API] 7325*/ 7326typedef struct sqlite3_backup sqlite3_backup; 7327 7328/* 7329** CAPI3REF: Online Backup API. 7330** 7331** The backup API copies the content of one database into another. 7332** It is useful either for creating backups of databases or 7333** for copying in-memory databases to or from persistent files. 7334** 7335** See Also: [Using the SQLite Online Backup API] 7336** 7337** ^SQLite holds a write transaction open on the destination database file 7338** for the duration of the backup operation. 7339** ^The source database is read-locked only while it is being read; 7340** it is not locked continuously for the entire backup operation. 7341** ^Thus, the backup may be performed on a live source database without 7342** preventing other database connections from 7343** reading or writing to the source database while the backup is underway. 7344** 7345** ^(To perform a backup operation: 7346** <ol> 7347** <li><b>sqlite3_backup_init()</b> is called once to initialize the 7348** backup, 7349** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 7350** the data between the two databases, and finally 7351** <li><b>sqlite3_backup_finish()</b> is called to release all resources 7352** associated with the backup operation. 7353** </ol>)^ 7354** There should be exactly one call to sqlite3_backup_finish() for each 7355** successful call to sqlite3_backup_init(). 7356** 7357** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 7358** 7359** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 7360** [database connection] associated with the destination database 7361** and the database name, respectively. 7362** ^The database name is "main" for the main database, "temp" for the 7363** temporary database, or the name specified after the AS keyword in 7364** an [ATTACH] statement for an attached database. 7365** ^The S and M arguments passed to 7366** sqlite3_backup_init(D,N,S,M) identify the [database connection] 7367** and database name of the source database, respectively. 7368** ^The source and destination [database connections] (parameters S and D) 7369** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 7370** an error. 7371** 7372** ^A call to sqlite3_backup_init() will fail, returning NULL, if 7373** there is already a read or read-write transaction open on the 7374** destination database. 7375** 7376** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 7377** returned and an error code and error message are stored in the 7378** destination [database connection] D. 7379** ^The error code and message for the failed call to sqlite3_backup_init() 7380** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 7381** [sqlite3_errmsg16()] functions. 7382** ^A successful call to sqlite3_backup_init() returns a pointer to an 7383** [sqlite3_backup] object. 7384** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 7385** sqlite3_backup_finish() functions to perform the specified backup 7386** operation. 7387** 7388** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 7389** 7390** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 7391** the source and destination databases specified by [sqlite3_backup] object B. 7392** ^If N is negative, all remaining source pages are copied. 7393** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 7394** are still more pages to be copied, then the function returns [SQLITE_OK]. 7395** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 7396** from source to destination, then it returns [SQLITE_DONE]. 7397** ^If an error occurs while running sqlite3_backup_step(B,N), 7398** then an [error code] is returned. ^As well as [SQLITE_OK] and 7399** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 7400** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 7401** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 7402** 7403** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 7404** <ol> 7405** <li> the destination database was opened read-only, or 7406** <li> the destination database is using write-ahead-log journaling 7407** and the destination and source page sizes differ, or 7408** <li> the destination database is an in-memory database and the 7409** destination and source page sizes differ. 7410** </ol>)^ 7411** 7412** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 7413** the [sqlite3_busy_handler | busy-handler function] 7414** is invoked (if one is specified). ^If the 7415** busy-handler returns non-zero before the lock is available, then 7416** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 7417** sqlite3_backup_step() can be retried later. ^If the source 7418** [database connection] 7419** is being used to write to the source database when sqlite3_backup_step() 7420** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 7421** case the call to sqlite3_backup_step() can be retried later on. ^(If 7422** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 7423** [SQLITE_READONLY] is returned, then 7424** there is no point in retrying the call to sqlite3_backup_step(). These 7425** errors are considered fatal.)^ The application must accept 7426** that the backup operation has failed and pass the backup operation handle 7427** to the sqlite3_backup_finish() to release associated resources. 7428** 7429** ^The first call to sqlite3_backup_step() obtains an exclusive lock 7430** on the destination file. ^The exclusive lock is not released until either 7431** sqlite3_backup_finish() is called or the backup operation is complete 7432** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 7433** sqlite3_backup_step() obtains a [shared lock] on the source database that 7434** lasts for the duration of the sqlite3_backup_step() call. 7435** ^Because the source database is not locked between calls to 7436** sqlite3_backup_step(), the source database may be modified mid-way 7437** through the backup process. ^If the source database is modified by an 7438** external process or via a database connection other than the one being 7439** used by the backup operation, then the backup will be automatically 7440** restarted by the next call to sqlite3_backup_step(). ^If the source 7441** database is modified by the using the same database connection as is used 7442** by the backup operation, then the backup database is automatically 7443** updated at the same time. 7444** 7445** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 7446** 7447** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 7448** application wishes to abandon the backup operation, the application 7449** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 7450** ^The sqlite3_backup_finish() interfaces releases all 7451** resources associated with the [sqlite3_backup] object. 7452** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 7453** active write-transaction on the destination database is rolled back. 7454** The [sqlite3_backup] object is invalid 7455** and may not be used following a call to sqlite3_backup_finish(). 7456** 7457** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 7458** sqlite3_backup_step() errors occurred, regardless or whether or not 7459** sqlite3_backup_step() completed. 7460** ^If an out-of-memory condition or IO error occurred during any prior 7461** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 7462** sqlite3_backup_finish() returns the corresponding [error code]. 7463** 7464** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 7465** is not a permanent error and does not affect the return value of 7466** sqlite3_backup_finish(). 7467** 7468** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 7469** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 7470** 7471** ^The sqlite3_backup_remaining() routine returns the number of pages still 7472** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 7473** ^The sqlite3_backup_pagecount() routine returns the total number of pages 7474** in the source database at the conclusion of the most recent 7475** sqlite3_backup_step(). 7476** ^(The values returned by these functions are only updated by 7477** sqlite3_backup_step(). If the source database is modified in a way that 7478** changes the size of the source database or the number of pages remaining, 7479** those changes are not reflected in the output of sqlite3_backup_pagecount() 7480** and sqlite3_backup_remaining() until after the next 7481** sqlite3_backup_step().)^ 7482** 7483** <b>Concurrent Usage of Database Handles</b> 7484** 7485** ^The source [database connection] may be used by the application for other 7486** purposes while a backup operation is underway or being initialized. 7487** ^If SQLite is compiled and configured to support threadsafe database 7488** connections, then the source database connection may be used concurrently 7489** from within other threads. 7490** 7491** However, the application must guarantee that the destination 7492** [database connection] is not passed to any other API (by any thread) after 7493** sqlite3_backup_init() is called and before the corresponding call to 7494** sqlite3_backup_finish(). SQLite does not currently check to see 7495** if the application incorrectly accesses the destination [database connection] 7496** and so no error code is reported, but the operations may malfunction 7497** nevertheless. Use of the destination database connection while a 7498** backup is in progress might also also cause a mutex deadlock. 7499** 7500** If running in [shared cache mode], the application must 7501** guarantee that the shared cache used by the destination database 7502** is not accessed while the backup is running. In practice this means 7503** that the application must guarantee that the disk file being 7504** backed up to is not accessed by any connection within the process, 7505** not just the specific connection that was passed to sqlite3_backup_init(). 7506** 7507** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7508** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7509** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7510** APIs are not strictly speaking threadsafe. If they are invoked at the 7511** same time as another thread is invoking sqlite3_backup_step() it is 7512** possible that they return invalid values. 7513*/ 7514sqlite3_backup *sqlite3_backup_init( 7515 sqlite3 *pDest, /* Destination database handle */ 7516 const char *zDestName, /* Destination database name */ 7517 sqlite3 *pSource, /* Source database handle */ 7518 const char *zSourceName /* Source database name */ 7519); 7520int sqlite3_backup_step(sqlite3_backup *p, int nPage); 7521int sqlite3_backup_finish(sqlite3_backup *p); 7522int sqlite3_backup_remaining(sqlite3_backup *p); 7523int sqlite3_backup_pagecount(sqlite3_backup *p); 7524 7525/* 7526** CAPI3REF: Unlock Notification 7527** METHOD: sqlite3 7528** 7529** ^When running in shared-cache mode, a database operation may fail with 7530** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7531** individual tables within the shared-cache cannot be obtained. See 7532** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7533** ^This API may be used to register a callback that SQLite will invoke 7534** when the connection currently holding the required lock relinquishes it. 7535** ^This API is only available if the library was compiled with the 7536** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7537** 7538** See Also: [Using the SQLite Unlock Notification Feature]. 7539** 7540** ^Shared-cache locks are released when a database connection concludes 7541** its current transaction, either by committing it or rolling it back. 7542** 7543** ^When a connection (known as the blocked connection) fails to obtain a 7544** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7545** identity of the database connection (the blocking connection) that 7546** has locked the required resource is stored internally. ^After an 7547** application receives an SQLITE_LOCKED error, it may call the 7548** sqlite3_unlock_notify() method with the blocked connection handle as 7549** the first argument to register for a callback that will be invoked 7550** when the blocking connections current transaction is concluded. ^The 7551** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7552** call that concludes the blocking connections transaction. 7553** 7554** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7555** there is a chance that the blocking connection will have already 7556** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7557** If this happens, then the specified callback is invoked immediately, 7558** from within the call to sqlite3_unlock_notify().)^ 7559** 7560** ^If the blocked connection is attempting to obtain a write-lock on a 7561** shared-cache table, and more than one other connection currently holds 7562** a read-lock on the same table, then SQLite arbitrarily selects one of 7563** the other connections to use as the blocking connection. 7564** 7565** ^(There may be at most one unlock-notify callback registered by a 7566** blocked connection. If sqlite3_unlock_notify() is called when the 7567** blocked connection already has a registered unlock-notify callback, 7568** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7569** called with a NULL pointer as its second argument, then any existing 7570** unlock-notify callback is canceled. ^The blocked connections 7571** unlock-notify callback may also be canceled by closing the blocked 7572** connection using [sqlite3_close()]. 7573** 7574** The unlock-notify callback is not reentrant. If an application invokes 7575** any sqlite3_xxx API functions from within an unlock-notify callback, a 7576** crash or deadlock may be the result. 7577** 7578** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7579** returns SQLITE_OK. 7580** 7581** <b>Callback Invocation Details</b> 7582** 7583** When an unlock-notify callback is registered, the application provides a 7584** single void* pointer that is passed to the callback when it is invoked. 7585** However, the signature of the callback function allows SQLite to pass 7586** it an array of void* context pointers. The first argument passed to 7587** an unlock-notify callback is a pointer to an array of void* pointers, 7588** and the second is the number of entries in the array. 7589** 7590** When a blocking connections transaction is concluded, there may be 7591** more than one blocked connection that has registered for an unlock-notify 7592** callback. ^If two or more such blocked connections have specified the 7593** same callback function, then instead of invoking the callback function 7594** multiple times, it is invoked once with the set of void* context pointers 7595** specified by the blocked connections bundled together into an array. 7596** This gives the application an opportunity to prioritize any actions 7597** related to the set of unblocked database connections. 7598** 7599** <b>Deadlock Detection</b> 7600** 7601** Assuming that after registering for an unlock-notify callback a 7602** database waits for the callback to be issued before taking any further 7603** action (a reasonable assumption), then using this API may cause the 7604** application to deadlock. For example, if connection X is waiting for 7605** connection Y's transaction to be concluded, and similarly connection 7606** Y is waiting on connection X's transaction, then neither connection 7607** will proceed and the system may remain deadlocked indefinitely. 7608** 7609** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7610** detection. ^If a given call to sqlite3_unlock_notify() would put the 7611** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7612** unlock-notify callback is registered. The system is said to be in 7613** a deadlocked state if connection A has registered for an unlock-notify 7614** callback on the conclusion of connection B's transaction, and connection 7615** B has itself registered for an unlock-notify callback when connection 7616** A's transaction is concluded. ^Indirect deadlock is also detected, so 7617** the system is also considered to be deadlocked if connection B has 7618** registered for an unlock-notify callback on the conclusion of connection 7619** C's transaction, where connection C is waiting on connection A. ^Any 7620** number of levels of indirection are allowed. 7621** 7622** <b>The "DROP TABLE" Exception</b> 7623** 7624** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7625** always appropriate to call sqlite3_unlock_notify(). There is however, 7626** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7627** SQLite checks if there are any currently executing SELECT statements 7628** that belong to the same connection. If there are, SQLITE_LOCKED is 7629** returned. In this case there is no "blocking connection", so invoking 7630** sqlite3_unlock_notify() results in the unlock-notify callback being 7631** invoked immediately. If the application then re-attempts the "DROP TABLE" 7632** or "DROP INDEX" query, an infinite loop might be the result. 7633** 7634** One way around this problem is to check the extended error code returned 7635** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7636** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7637** the special "DROP TABLE/INDEX" case, the extended error code is just 7638** SQLITE_LOCKED.)^ 7639*/ 7640int sqlite3_unlock_notify( 7641 sqlite3 *pBlocked, /* Waiting connection */ 7642 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7643 void *pNotifyArg /* Argument to pass to xNotify */ 7644); 7645 7646 7647/* 7648** CAPI3REF: String Comparison 7649** 7650** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7651** and extensions to compare the contents of two buffers containing UTF-8 7652** strings in a case-independent fashion, using the same definition of "case 7653** independence" that SQLite uses internally when comparing identifiers. 7654*/ 7655int sqlite3_stricmp(const char *, const char *); 7656int sqlite3_strnicmp(const char *, const char *, int); 7657 7658/* 7659** CAPI3REF: String Globbing 7660* 7661** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 7662** string X matches the [GLOB] pattern P. 7663** ^The definition of [GLOB] pattern matching used in 7664** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7665** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 7666** is case sensitive. 7667** 7668** Note that this routine returns zero on a match and non-zero if the strings 7669** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7670** 7671** See also: [sqlite3_strlike()]. 7672*/ 7673int sqlite3_strglob(const char *zGlob, const char *zStr); 7674 7675/* 7676** CAPI3REF: String LIKE Matching 7677* 7678** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 7679** string X matches the [LIKE] pattern P with escape character E. 7680** ^The definition of [LIKE] pattern matching used in 7681** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 7682** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 7683** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 7684** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 7685** insensitive - equivalent upper and lower case ASCII characters match 7686** one another. 7687** 7688** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 7689** only ASCII characters are case folded. 7690** 7691** Note that this routine returns zero on a match and non-zero if the strings 7692** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7693** 7694** See also: [sqlite3_strglob()]. 7695*/ 7696int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 7697 7698/* 7699** CAPI3REF: Error Logging Interface 7700** 7701** ^The [sqlite3_log()] interface writes a message into the [error log] 7702** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7703** ^If logging is enabled, the zFormat string and subsequent arguments are 7704** used with [sqlite3_snprintf()] to generate the final output string. 7705** 7706** The sqlite3_log() interface is intended for use by extensions such as 7707** virtual tables, collating functions, and SQL functions. While there is 7708** nothing to prevent an application from calling sqlite3_log(), doing so 7709** is considered bad form. 7710** 7711** The zFormat string must not be NULL. 7712** 7713** To avoid deadlocks and other threading problems, the sqlite3_log() routine 7714** will not use dynamically allocated memory. The log message is stored in 7715** a fixed-length buffer on the stack. If the log message is longer than 7716** a few hundred characters, it will be truncated to the length of the 7717** buffer. 7718*/ 7719void sqlite3_log(int iErrCode, const char *zFormat, ...); 7720 7721/* 7722** CAPI3REF: Write-Ahead Log Commit Hook 7723** METHOD: sqlite3 7724** 7725** ^The [sqlite3_wal_hook()] function is used to register a callback that 7726** is invoked each time data is committed to a database in wal mode. 7727** 7728** ^(The callback is invoked by SQLite after the commit has taken place and 7729** the associated write-lock on the database released)^, so the implementation 7730** may read, write or [checkpoint] the database as required. 7731** 7732** ^The first parameter passed to the callback function when it is invoked 7733** is a copy of the third parameter passed to sqlite3_wal_hook() when 7734** registering the callback. ^The second is a copy of the database handle. 7735** ^The third parameter is the name of the database that was written to - 7736** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 7737** is the number of pages currently in the write-ahead log file, 7738** including those that were just committed. 7739** 7740** The callback function should normally return [SQLITE_OK]. ^If an error 7741** code is returned, that error will propagate back up through the 7742** SQLite code base to cause the statement that provoked the callback 7743** to report an error, though the commit will have still occurred. If the 7744** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 7745** that does not correspond to any valid SQLite error code, the results 7746** are undefined. 7747** 7748** A single database handle may have at most a single write-ahead log callback 7749** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 7750** previously registered write-ahead log callback. ^Note that the 7751** [sqlite3_wal_autocheckpoint()] interface and the 7752** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 7753** overwrite any prior [sqlite3_wal_hook()] settings. 7754*/ 7755void *sqlite3_wal_hook( 7756 sqlite3*, 7757 int(*)(void *,sqlite3*,const char*,int), 7758 void* 7759); 7760 7761/* 7762** CAPI3REF: Configure an auto-checkpoint 7763** METHOD: sqlite3 7764** 7765** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 7766** [sqlite3_wal_hook()] that causes any database on [database connection] D 7767** to automatically [checkpoint] 7768** after committing a transaction if there are N or 7769** more frames in the [write-ahead log] file. ^Passing zero or 7770** a negative value as the nFrame parameter disables automatic 7771** checkpoints entirely. 7772** 7773** ^The callback registered by this function replaces any existing callback 7774** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 7775** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 7776** configured by this function. 7777** 7778** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 7779** from SQL. 7780** 7781** ^Checkpoints initiated by this mechanism are 7782** [sqlite3_wal_checkpoint_v2|PASSIVE]. 7783** 7784** ^Every new [database connection] defaults to having the auto-checkpoint 7785** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 7786** pages. The use of this interface 7787** is only necessary if the default setting is found to be suboptimal 7788** for a particular application. 7789*/ 7790int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 7791 7792/* 7793** CAPI3REF: Checkpoint a database 7794** METHOD: sqlite3 7795** 7796** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 7797** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 7798** 7799** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 7800** [write-ahead log] for database X on [database connection] D to be 7801** transferred into the database file and for the write-ahead log to 7802** be reset. See the [checkpointing] documentation for addition 7803** information. 7804** 7805** This interface used to be the only way to cause a checkpoint to 7806** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 7807** interface was added. This interface is retained for backwards 7808** compatibility and as a convenience for applications that need to manually 7809** start a callback but which do not need the full power (and corresponding 7810** complication) of [sqlite3_wal_checkpoint_v2()]. 7811*/ 7812int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 7813 7814/* 7815** CAPI3REF: Checkpoint a database 7816** METHOD: sqlite3 7817** 7818** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 7819** operation on database X of [database connection] D in mode M. Status 7820** information is written back into integers pointed to by L and C.)^ 7821** ^(The M parameter must be a valid [checkpoint mode]:)^ 7822** 7823** <dl> 7824** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 7825** ^Checkpoint as many frames as possible without waiting for any database 7826** readers or writers to finish, then sync the database file if all frames 7827** in the log were checkpointed. ^The [busy-handler callback] 7828** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 7829** ^On the other hand, passive mode might leave the checkpoint unfinished 7830** if there are concurrent readers or writers. 7831** 7832** <dt>SQLITE_CHECKPOINT_FULL<dd> 7833** ^This mode blocks (it invokes the 7834** [sqlite3_busy_handler|busy-handler callback]) until there is no 7835** database writer and all readers are reading from the most recent database 7836** snapshot. ^It then checkpoints all frames in the log file and syncs the 7837** database file. ^This mode blocks new database writers while it is pending, 7838** but new database readers are allowed to continue unimpeded. 7839** 7840** <dt>SQLITE_CHECKPOINT_RESTART<dd> 7841** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 7842** that after checkpointing the log file it blocks (calls the 7843** [busy-handler callback]) 7844** until all readers are reading from the database file only. ^This ensures 7845** that the next writer will restart the log file from the beginning. 7846** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 7847** database writer attempts while it is pending, but does not impede readers. 7848** 7849** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 7850** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 7851** addition that it also truncates the log file to zero bytes just prior 7852** to a successful return. 7853** </dl> 7854** 7855** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 7856** the log file or to -1 if the checkpoint could not run because 7857** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 7858** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 7859** log file (including any that were already checkpointed before the function 7860** was called) or to -1 if the checkpoint could not run due to an error or 7861** because the database is not in WAL mode. ^Note that upon successful 7862** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 7863** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 7864** 7865** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 7866** any other process is running a checkpoint operation at the same time, the 7867** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 7868** busy-handler configured, it will not be invoked in this case. 7869** 7870** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 7871** exclusive "writer" lock on the database file. ^If the writer lock cannot be 7872** obtained immediately, and a busy-handler is configured, it is invoked and 7873** the writer lock retried until either the busy-handler returns 0 or the lock 7874** is successfully obtained. ^The busy-handler is also invoked while waiting for 7875** database readers as described above. ^If the busy-handler returns 0 before 7876** the writer lock is obtained or while waiting for database readers, the 7877** checkpoint operation proceeds from that point in the same way as 7878** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 7879** without blocking any further. ^SQLITE_BUSY is returned in this case. 7880** 7881** ^If parameter zDb is NULL or points to a zero length string, then the 7882** specified operation is attempted on all WAL databases [attached] to 7883** [database connection] db. In this case the 7884** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 7885** an SQLITE_BUSY error is encountered when processing one or more of the 7886** attached WAL databases, the operation is still attempted on any remaining 7887** attached databases and SQLITE_BUSY is returned at the end. ^If any other 7888** error occurs while processing an attached database, processing is abandoned 7889** and the error code is returned to the caller immediately. ^If no error 7890** (SQLITE_BUSY or otherwise) is encountered while processing the attached 7891** databases, SQLITE_OK is returned. 7892** 7893** ^If database zDb is the name of an attached database that is not in WAL 7894** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 7895** zDb is not NULL (or a zero length string) and is not the name of any 7896** attached database, SQLITE_ERROR is returned to the caller. 7897** 7898** ^Unless it returns SQLITE_MISUSE, 7899** the sqlite3_wal_checkpoint_v2() interface 7900** sets the error information that is queried by 7901** [sqlite3_errcode()] and [sqlite3_errmsg()]. 7902** 7903** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 7904** from SQL. 7905*/ 7906int sqlite3_wal_checkpoint_v2( 7907 sqlite3 *db, /* Database handle */ 7908 const char *zDb, /* Name of attached database (or NULL) */ 7909 int eMode, /* SQLITE_CHECKPOINT_* value */ 7910 int *pnLog, /* OUT: Size of WAL log in frames */ 7911 int *pnCkpt /* OUT: Total number of frames checkpointed */ 7912); 7913 7914/* 7915** CAPI3REF: Checkpoint Mode Values 7916** KEYWORDS: {checkpoint mode} 7917** 7918** These constants define all valid values for the "checkpoint mode" passed 7919** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 7920** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 7921** meaning of each of these checkpoint modes. 7922*/ 7923#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 7924#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 7925#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 7926#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 7927 7928/* 7929** CAPI3REF: Virtual Table Interface Configuration 7930** 7931** This function may be called by either the [xConnect] or [xCreate] method 7932** of a [virtual table] implementation to configure 7933** various facets of the virtual table interface. 7934** 7935** If this interface is invoked outside the context of an xConnect or 7936** xCreate virtual table method then the behavior is undefined. 7937** 7938** At present, there is only one option that may be configured using 7939** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 7940** may be added in the future. 7941*/ 7942int sqlite3_vtab_config(sqlite3*, int op, ...); 7943 7944/* 7945** CAPI3REF: Virtual Table Configuration Options 7946** 7947** These macros define the various options to the 7948** [sqlite3_vtab_config()] interface that [virtual table] implementations 7949** can use to customize and optimize their behavior. 7950** 7951** <dl> 7952** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 7953** <dd>Calls of the form 7954** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 7955** where X is an integer. If X is zero, then the [virtual table] whose 7956** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 7957** support constraints. In this configuration (which is the default) if 7958** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 7959** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 7960** specified as part of the users SQL statement, regardless of the actual 7961** ON CONFLICT mode specified. 7962** 7963** If X is non-zero, then the virtual table implementation guarantees 7964** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 7965** any modifications to internal or persistent data structures have been made. 7966** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 7967** is able to roll back a statement or database transaction, and abandon 7968** or continue processing the current SQL statement as appropriate. 7969** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 7970** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 7971** had been ABORT. 7972** 7973** Virtual table implementations that are required to handle OR REPLACE 7974** must do so within the [xUpdate] method. If a call to the 7975** [sqlite3_vtab_on_conflict()] function indicates that the current ON 7976** CONFLICT policy is REPLACE, the virtual table implementation should 7977** silently replace the appropriate rows within the xUpdate callback and 7978** return SQLITE_OK. Or, if this is not possible, it may return 7979** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 7980** constraint handling. 7981** </dl> 7982*/ 7983#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 7984 7985/* 7986** CAPI3REF: Determine The Virtual Table Conflict Policy 7987** 7988** This function may only be called from within a call to the [xUpdate] method 7989** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 7990** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 7991** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 7992** of the SQL statement that triggered the call to the [xUpdate] method of the 7993** [virtual table]. 7994*/ 7995int sqlite3_vtab_on_conflict(sqlite3 *); 7996 7997/* 7998** CAPI3REF: Conflict resolution modes 7999** KEYWORDS: {conflict resolution mode} 8000** 8001** These constants are returned by [sqlite3_vtab_on_conflict()] to 8002** inform a [virtual table] implementation what the [ON CONFLICT] mode 8003** is for the SQL statement being evaluated. 8004** 8005** Note that the [SQLITE_IGNORE] constant is also used as a potential 8006** return value from the [sqlite3_set_authorizer()] callback and that 8007** [SQLITE_ABORT] is also a [result code]. 8008*/ 8009#define SQLITE_ROLLBACK 1 8010/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 8011#define SQLITE_FAIL 3 8012/* #define SQLITE_ABORT 4 // Also an error code */ 8013#define SQLITE_REPLACE 5 8014 8015/* 8016** CAPI3REF: Prepared Statement Scan Status Opcodes 8017** KEYWORDS: {scanstatus options} 8018** 8019** The following constants can be used for the T parameter to the 8020** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 8021** different metric for sqlite3_stmt_scanstatus() to return. 8022** 8023** When the value returned to V is a string, space to hold that string is 8024** managed by the prepared statement S and will be automatically freed when 8025** S is finalized. 8026** 8027** <dl> 8028** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 8029** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 8030** set to the total number of times that the X-th loop has run.</dd> 8031** 8032** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 8033** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 8034** to the total number of rows examined by all iterations of the X-th loop.</dd> 8035** 8036** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 8037** <dd>^The "double" variable pointed to by the T parameter will be set to the 8038** query planner's estimate for the average number of rows output from each 8039** iteration of the X-th loop. If the query planner's estimates was accurate, 8040** then this value will approximate the quotient NVISIT/NLOOP and the 8041** product of this value for all prior loops with the same SELECTID will 8042** be the NLOOP value for the current loop. 8043** 8044** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 8045** <dd>^The "const char *" variable pointed to by the T parameter will be set 8046** to a zero-terminated UTF-8 string containing the name of the index or table 8047** used for the X-th loop. 8048** 8049** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 8050** <dd>^The "const char *" variable pointed to by the T parameter will be set 8051** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 8052** description for the X-th loop. 8053** 8054** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 8055** <dd>^The "int" variable pointed to by the T parameter will be set to the 8056** "select-id" for the X-th loop. The select-id identifies which query or 8057** subquery the loop is part of. The main query has a select-id of zero. 8058** The select-id is the same value as is output in the first column 8059** of an [EXPLAIN QUERY PLAN] query. 8060** </dl> 8061*/ 8062#define SQLITE_SCANSTAT_NLOOP 0 8063#define SQLITE_SCANSTAT_NVISIT 1 8064#define SQLITE_SCANSTAT_EST 2 8065#define SQLITE_SCANSTAT_NAME 3 8066#define SQLITE_SCANSTAT_EXPLAIN 4 8067#define SQLITE_SCANSTAT_SELECTID 5 8068 8069/* 8070** CAPI3REF: Prepared Statement Scan Status 8071** METHOD: sqlite3_stmt 8072** 8073** This interface returns information about the predicted and measured 8074** performance for pStmt. Advanced applications can use this 8075** interface to compare the predicted and the measured performance and 8076** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 8077** 8078** Since this interface is expected to be rarely used, it is only 8079** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 8080** compile-time option. 8081** 8082** The "iScanStatusOp" parameter determines which status information to return. 8083** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 8084** of this interface is undefined. 8085** ^The requested measurement is written into a variable pointed to by 8086** the "pOut" parameter. 8087** Parameter "idx" identifies the specific loop to retrieve statistics for. 8088** Loops are numbered starting from zero. ^If idx is out of range - less than 8089** zero or greater than or equal to the total number of loops used to implement 8090** the statement - a non-zero value is returned and the variable that pOut 8091** points to is unchanged. 8092** 8093** ^Statistics might not be available for all loops in all statements. ^In cases 8094** where there exist loops with no available statistics, this function behaves 8095** as if the loop did not exist - it returns non-zero and leave the variable 8096** that pOut points to unchanged. 8097** 8098** See also: [sqlite3_stmt_scanstatus_reset()] 8099*/ 8100int sqlite3_stmt_scanstatus( 8101 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 8102 int idx, /* Index of loop to report on */ 8103 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 8104 void *pOut /* Result written here */ 8105); 8106 8107/* 8108** CAPI3REF: Zero Scan-Status Counters 8109** METHOD: sqlite3_stmt 8110** 8111** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 8112** 8113** This API is only available if the library is built with pre-processor 8114** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 8115*/ 8116void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 8117 8118/* 8119** CAPI3REF: Flush caches to disk mid-transaction 8120** 8121** ^If a write-transaction is open on [database connection] D when the 8122** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 8123** pages in the pager-cache that are not currently in use are written out 8124** to disk. A dirty page may be in use if a database cursor created by an 8125** active SQL statement is reading from it, or if it is page 1 of a database 8126** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 8127** interface flushes caches for all schemas - "main", "temp", and 8128** any [attached] databases. 8129** 8130** ^If this function needs to obtain extra database locks before dirty pages 8131** can be flushed to disk, it does so. ^If those locks cannot be obtained 8132** immediately and there is a busy-handler callback configured, it is invoked 8133** in the usual manner. ^If the required lock still cannot be obtained, then 8134** the database is skipped and an attempt made to flush any dirty pages 8135** belonging to the next (if any) database. ^If any databases are skipped 8136** because locks cannot be obtained, but no other error occurs, this 8137** function returns SQLITE_BUSY. 8138** 8139** ^If any other error occurs while flushing dirty pages to disk (for 8140** example an IO error or out-of-memory condition), then processing is 8141** abandoned and an SQLite [error code] is returned to the caller immediately. 8142** 8143** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 8144** 8145** ^This function does not set the database handle error code or message 8146** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 8147*/ 8148int sqlite3_db_cacheflush(sqlite3*); 8149 8150/* 8151** CAPI3REF: The pre-update hook. 8152** 8153** ^These interfaces are only available if SQLite is compiled using the 8154** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 8155** 8156** ^The [sqlite3_preupdate_hook()] interface registers a callback function 8157** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 8158** on a [rowid table]. 8159** ^At most one preupdate hook may be registered at a time on a single 8160** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 8161** the previous setting. 8162** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 8163** with a NULL pointer as the second parameter. 8164** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 8165** the first parameter to callbacks. 8166** 8167** ^The preupdate hook only fires for changes to [rowid tables]; the preupdate 8168** hook is not invoked for changes to [virtual tables] or [WITHOUT ROWID] 8169** tables. 8170** 8171** ^The second parameter to the preupdate callback is a pointer to 8172** the [database connection] that registered the preupdate hook. 8173** ^The third parameter to the preupdate callback is one of the constants 8174** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 8175** kind of update operation that is about to occur. 8176** ^(The fourth parameter to the preupdate callback is the name of the 8177** database within the database connection that is being modified. This 8178** will be "main" for the main database or "temp" for TEMP tables or 8179** the name given after the AS keyword in the [ATTACH] statement for attached 8180** databases.)^ 8181** ^The fifth parameter to the preupdate callback is the name of the 8182** table that is being modified. 8183** ^The sixth parameter to the preupdate callback is the initial [rowid] of the 8184** row being changes for SQLITE_UPDATE and SQLITE_DELETE changes and is 8185** undefined for SQLITE_INSERT changes. 8186** ^The seventh parameter to the preupdate callback is the final [rowid] of 8187** the row being changed for SQLITE_UPDATE and SQLITE_INSERT changes and is 8188** undefined for SQLITE_DELETE changes. 8189** 8190** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 8191** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 8192** provide additional information about a preupdate event. These routines 8193** may only be called from within a preupdate callback. Invoking any of 8194** these routines from outside of a preupdate callback or with a 8195** [database connection] pointer that is different from the one supplied 8196** to the preupdate callback results in undefined and probably undesirable 8197** behavior. 8198** 8199** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 8200** in the row that is being inserted, updated, or deleted. 8201** 8202** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 8203** a [protected sqlite3_value] that contains the value of the Nth column of 8204** the table row before it is updated. The N parameter must be between 0 8205** and one less than the number of columns or the behavior will be 8206** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 8207** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 8208** behavior is undefined. The [sqlite3_value] that P points to 8209** will be destroyed when the preupdate callback returns. 8210** 8211** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 8212** a [protected sqlite3_value] that contains the value of the Nth column of 8213** the table row after it is updated. The N parameter must be between 0 8214** and one less than the number of columns or the behavior will be 8215** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 8216** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 8217** behavior is undefined. The [sqlite3_value] that P points to 8218** will be destroyed when the preupdate callback returns. 8219** 8220** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 8221** callback was invoked as a result of a direct insert, update, or delete 8222** operation; or 1 for inserts, updates, or deletes invoked by top-level 8223** triggers; or 2 for changes resulting from triggers called by top-level 8224** triggers; and so forth. 8225** 8226** See also: [sqlite3_update_hook()] 8227*/ 8228SQLITE_EXPERIMENTAL void *sqlite3_preupdate_hook( 8229 sqlite3 *db, 8230 void(*xPreUpdate)( 8231 void *pCtx, /* Copy of third arg to preupdate_hook() */ 8232 sqlite3 *db, /* Database handle */ 8233 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 8234 char const *zDb, /* Database name */ 8235 char const *zName, /* Table name */ 8236 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 8237 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 8238 ), 8239 void* 8240); 8241SQLITE_EXPERIMENTAL int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 8242SQLITE_EXPERIMENTAL int sqlite3_preupdate_count(sqlite3 *); 8243SQLITE_EXPERIMENTAL int sqlite3_preupdate_depth(sqlite3 *); 8244SQLITE_EXPERIMENTAL int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 8245 8246/* 8247** CAPI3REF: Low-level system error code 8248** 8249** ^Attempt to return the underlying operating system error code or error 8250** number that caused the most recent I/O error or failure to open a file. 8251** The return value is OS-dependent. For example, on unix systems, after 8252** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 8253** called to get back the underlying "errno" that caused the problem, such 8254** as ENOSPC, EAUTH, EISDIR, and so forth. 8255*/ 8256int sqlite3_system_errno(sqlite3*); 8257 8258/* 8259** CAPI3REF: Database Snapshot 8260** KEYWORDS: {snapshot} 8261** EXPERIMENTAL 8262** 8263** An instance of the snapshot object records the state of a [WAL mode] 8264** database for some specific point in history. 8265** 8266** In [WAL mode], multiple [database connections] that are open on the 8267** same database file can each be reading a different historical version 8268** of the database file. When a [database connection] begins a read 8269** transaction, that connection sees an unchanging copy of the database 8270** as it existed for the point in time when the transaction first started. 8271** Subsequent changes to the database from other connections are not seen 8272** by the reader until a new read transaction is started. 8273** 8274** The sqlite3_snapshot object records state information about an historical 8275** version of the database file so that it is possible to later open a new read 8276** transaction that sees that historical version of the database rather than 8277** the most recent version. 8278** 8279** The constructor for this object is [sqlite3_snapshot_get()]. The 8280** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer 8281** to an historical snapshot (if possible). The destructor for 8282** sqlite3_snapshot objects is [sqlite3_snapshot_free()]. 8283*/ 8284typedef struct sqlite3_snapshot sqlite3_snapshot; 8285 8286/* 8287** CAPI3REF: Record A Database Snapshot 8288** EXPERIMENTAL 8289** 8290** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 8291** new [sqlite3_snapshot] object that records the current state of 8292** schema S in database connection D. ^On success, the 8293** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 8294** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 8295** ^If schema S of [database connection] D is not a [WAL mode] database 8296** that is in a read transaction, then [sqlite3_snapshot_get(D,S,P)] 8297** leaves the *P value unchanged and returns an appropriate [error code]. 8298** 8299** The [sqlite3_snapshot] object returned from a successful call to 8300** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 8301** to avoid a memory leak. 8302** 8303** The [sqlite3_snapshot_get()] interface is only available when the 8304** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8305*/ 8306SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 8307 sqlite3 *db, 8308 const char *zSchema, 8309 sqlite3_snapshot **ppSnapshot 8310); 8311 8312/* 8313** CAPI3REF: Start a read transaction on an historical snapshot 8314** EXPERIMENTAL 8315** 8316** ^The [sqlite3_snapshot_open(D,S,P)] interface starts a 8317** read transaction for schema S of 8318** [database connection] D such that the read transaction 8319** refers to historical [snapshot] P, rather than the most 8320** recent change to the database. 8321** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success 8322** or an appropriate [error code] if it fails. 8323** 8324** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be 8325** the first operation following the [BEGIN] that takes the schema S 8326** out of [autocommit mode]. 8327** ^In other words, schema S must not currently be in 8328** a transaction for [sqlite3_snapshot_open(D,S,P)] to work, but the 8329** database connection D must be out of [autocommit mode]. 8330** ^A [snapshot] will fail to open if it has been overwritten by a 8331** [checkpoint]. 8332** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 8333** database connection D does not know that the database file for 8334** schema S is in [WAL mode]. A database connection might not know 8335** that the database file is in [WAL mode] if there has been no prior 8336** I/O on that database connection, or if the database entered [WAL mode] 8337** after the most recent I/O on the database connection.)^ 8338** (Hint: Run "[PRAGMA application_id]" against a newly opened 8339** database connection in order to make it ready to use snapshots.) 8340** 8341** The [sqlite3_snapshot_open()] interface is only available when the 8342** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8343*/ 8344SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 8345 sqlite3 *db, 8346 const char *zSchema, 8347 sqlite3_snapshot *pSnapshot 8348); 8349 8350/* 8351** CAPI3REF: Destroy a snapshot 8352** EXPERIMENTAL 8353** 8354** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 8355** The application must eventually free every [sqlite3_snapshot] object 8356** using this routine to avoid a memory leak. 8357** 8358** The [sqlite3_snapshot_free()] interface is only available when the 8359** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8360*/ 8361SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 8362 8363/* 8364** CAPI3REF: Compare the ages of two snapshot handles. 8365** EXPERIMENTAL 8366** 8367** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 8368** of two valid snapshot handles. 8369** 8370** If the two snapshot handles are not associated with the same database 8371** file, the result of the comparison is undefined. 8372** 8373** Additionally, the result of the comparison is only valid if both of the 8374** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 8375** last time the wal file was deleted. The wal file is deleted when the 8376** database is changed back to rollback mode or when the number of database 8377** clients drops to zero. If either snapshot handle was obtained before the 8378** wal file was last deleted, the value returned by this function 8379** is undefined. 8380** 8381** Otherwise, this API returns a negative value if P1 refers to an older 8382** snapshot than P2, zero if the two handles refer to the same database 8383** snapshot, and a positive value if P1 is a newer snapshot than P2. 8384*/ 8385SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 8386 sqlite3_snapshot *p1, 8387 sqlite3_snapshot *p2 8388); 8389 8390/* 8391** Undo the hack that converts floating point types to integer for 8392** builds on processors without floating point support. 8393*/ 8394#ifdef SQLITE_OMIT_FLOATING_POINT 8395# undef double 8396#endif 8397 8398#ifdef __cplusplus 8399} /* End of the 'extern "C"' block */ 8400#endif 8401#endif /* SQLITE3_H */ 8402