1/* 2** 2001-09-15 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 a SHA1 118** or SHA3-256 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# ifdef SQLITE_UINT64_TYPE 263 typedef SQLITE_UINT64_TYPE sqlite_uint64; 264# else 265 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 266# endif 267#elif defined(_MSC_VER) || defined(__BORLANDC__) 268 typedef __int64 sqlite_int64; 269 typedef unsigned __int64 sqlite_uint64; 270#else 271 typedef long long int sqlite_int64; 272 typedef unsigned long long int sqlite_uint64; 273#endif 274typedef sqlite_int64 sqlite3_int64; 275typedef sqlite_uint64 sqlite3_uint64; 276 277/* 278** If compiling for a processor that lacks floating point support, 279** substitute integer for floating-point. 280*/ 281#ifdef SQLITE_OMIT_FLOATING_POINT 282# define double sqlite3_int64 283#endif 284 285/* 286** CAPI3REF: Closing A Database Connection 287** DESTRUCTOR: sqlite3 288** 289** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 290** for the [sqlite3] object. 291** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 292** the [sqlite3] object is successfully destroyed and all associated 293** resources are deallocated. 294** 295** ^If the database connection is associated with unfinalized prepared 296** statements or unfinished sqlite3_backup objects then sqlite3_close() 297** will leave the database connection open and return [SQLITE_BUSY]. 298** ^If sqlite3_close_v2() is called with unfinalized prepared statements 299** and/or unfinished sqlite3_backups, then the database connection becomes 300** an unusable "zombie" which will automatically be deallocated when the 301** last prepared statement is finalized or the last sqlite3_backup is 302** finished. The sqlite3_close_v2() interface is intended for use with 303** host languages that are garbage collected, and where the order in which 304** destructors are called is arbitrary. 305** 306** Applications should [sqlite3_finalize | finalize] all [prepared statements], 307** [sqlite3_blob_close | close] all [BLOB handles], and 308** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 309** with the [sqlite3] object prior to attempting to close the object. ^If 310** sqlite3_close_v2() is called on a [database connection] that still has 311** outstanding [prepared statements], [BLOB handles], and/or 312** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation 313** of resources is deferred until all [prepared statements], [BLOB handles], 314** and [sqlite3_backup] objects are also destroyed. 315** 316** ^If an [sqlite3] object is destroyed while a transaction is open, 317** the transaction is automatically rolled back. 318** 319** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 320** must be either a NULL 321** pointer or an [sqlite3] object pointer obtained 322** from [sqlite3_open()], [sqlite3_open16()], or 323** [sqlite3_open_v2()], and not previously closed. 324** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 325** argument is a harmless no-op. 326*/ 327int sqlite3_close(sqlite3*); 328int sqlite3_close_v2(sqlite3*); 329 330/* 331** The type for a callback function. 332** This is legacy and deprecated. It is included for historical 333** compatibility and is not documented. 334*/ 335typedef int (*sqlite3_callback)(void*,int,char**, char**); 336 337/* 338** CAPI3REF: One-Step Query Execution Interface 339** METHOD: sqlite3 340** 341** The sqlite3_exec() interface is a convenience wrapper around 342** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 343** that allows an application to run multiple statements of SQL 344** without having to use a lot of C code. 345** 346** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 347** semicolon-separate SQL statements passed into its 2nd argument, 348** in the context of the [database connection] passed in as its 1st 349** argument. ^If the callback function of the 3rd argument to 350** sqlite3_exec() is not NULL, then it is invoked for each result row 351** coming out of the evaluated SQL statements. ^The 4th argument to 352** sqlite3_exec() is relayed through to the 1st argument of each 353** callback invocation. ^If the callback pointer to sqlite3_exec() 354** is NULL, then no callback is ever invoked and result rows are 355** ignored. 356** 357** ^If an error occurs while evaluating the SQL statements passed into 358** sqlite3_exec(), then execution of the current statement stops and 359** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 360** is not NULL then any error message is written into memory obtained 361** from [sqlite3_malloc()] and passed back through the 5th parameter. 362** To avoid memory leaks, the application should invoke [sqlite3_free()] 363** on error message strings returned through the 5th parameter of 364** sqlite3_exec() after the error message string is no longer needed. 365** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 366** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 367** NULL before returning. 368** 369** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 370** routine returns SQLITE_ABORT without invoking the callback again and 371** without running any subsequent SQL statements. 372** 373** ^The 2nd argument to the sqlite3_exec() callback function is the 374** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 375** callback is an array of pointers to strings obtained as if from 376** [sqlite3_column_text()], one for each column. ^If an element of a 377** result row is NULL then the corresponding string pointer for the 378** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 379** sqlite3_exec() callback is an array of pointers to strings where each 380** entry represents the name of corresponding result column as obtained 381** from [sqlite3_column_name()]. 382** 383** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 384** to an empty string, or a pointer that contains only whitespace and/or 385** SQL comments, then no SQL statements are evaluated and the database 386** is not changed. 387** 388** Restrictions: 389** 390** <ul> 391** <li> The application must ensure that the 1st parameter to sqlite3_exec() 392** is a valid and open [database connection]. 393** <li> The application must not close the [database connection] specified by 394** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 395** <li> The application must not modify the SQL statement text passed into 396** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 397** </ul> 398*/ 399int sqlite3_exec( 400 sqlite3*, /* An open database */ 401 const char *sql, /* SQL to be evaluated */ 402 int (*callback)(void*,int,char**,char**), /* Callback function */ 403 void *, /* 1st argument to callback */ 404 char **errmsg /* Error msg written here */ 405); 406 407/* 408** CAPI3REF: Result Codes 409** KEYWORDS: {result code definitions} 410** 411** Many SQLite functions return an integer result code from the set shown 412** here in order to indicate success or failure. 413** 414** New error codes may be added in future versions of SQLite. 415** 416** See also: [extended result code definitions] 417*/ 418#define SQLITE_OK 0 /* Successful result */ 419/* beginning-of-error-codes */ 420#define SQLITE_ERROR 1 /* Generic error */ 421#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 422#define SQLITE_PERM 3 /* Access permission denied */ 423#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 424#define SQLITE_BUSY 5 /* The database file is locked */ 425#define SQLITE_LOCKED 6 /* A table in the database is locked */ 426#define SQLITE_NOMEM 7 /* A malloc() failed */ 427#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 428#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 429#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 430#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 431#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 432#define SQLITE_FULL 13 /* Insertion failed because database is full */ 433#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 434#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 435#define SQLITE_EMPTY 16 /* Not used */ 436#define SQLITE_SCHEMA 17 /* The database schema changed */ 437#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 438#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 439#define SQLITE_MISMATCH 20 /* Data type mismatch */ 440#define SQLITE_MISUSE 21 /* Library used incorrectly */ 441#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 442#define SQLITE_AUTH 23 /* Authorization denied */ 443#define SQLITE_FORMAT 24 /* Not used */ 444#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 445#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 446#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 447#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 448#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 449#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 450/* end-of-error-codes */ 451 452/* 453** CAPI3REF: Extended Result Codes 454** KEYWORDS: {extended result code definitions} 455** 456** In its default configuration, SQLite API routines return one of 30 integer 457** [result codes]. However, experience has shown that many of 458** these result codes are too coarse-grained. They do not provide as 459** much information about problems as programmers might like. In an effort to 460** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8] 461** and later) include 462** support for additional result codes that provide more detailed information 463** about errors. These [extended result codes] are enabled or disabled 464** on a per database connection basis using the 465** [sqlite3_extended_result_codes()] API. Or, the extended code for 466** the most recent error can be obtained using 467** [sqlite3_extended_errcode()]. 468*/ 469#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 470#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 471#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 472#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 473#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 474#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 475#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 476#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 477#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 478#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 479#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 480#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 481#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 482#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 483#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 484#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 485#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 486#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 487#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 488#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 489#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 490#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 491#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 492#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 493#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 494#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 495#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8)) 496#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8)) 497#define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8)) 498#define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8)) 499#define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8)) 500#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 501#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 502#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 503#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 504#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 505#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 506#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 507#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 508#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 509#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 510#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 511#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 512#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 513#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 514#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 515#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 516#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 517#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 518#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 519#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 520#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 521#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 522#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 523#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 524#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 525#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 526#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 527#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8)) 528 529/* 530** CAPI3REF: Flags For File Open Operations 531** 532** These bit values are intended for use in the 533** 3rd parameter to the [sqlite3_open_v2()] interface and 534** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 535*/ 536#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 537#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 538#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 539#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 540#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 541#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 542#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 543#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 544#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 545#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 546#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 547#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 548#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 549#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 550#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 551#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 552#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 553#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 554#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 555#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 556 557/* Reserved: 0x00F00000 */ 558 559/* 560** CAPI3REF: Device Characteristics 561** 562** The xDeviceCharacteristics method of the [sqlite3_io_methods] 563** object returns an integer which is a vector of these 564** bit values expressing I/O characteristics of the mass storage 565** device that holds the file that the [sqlite3_io_methods] 566** refers to. 567** 568** The SQLITE_IOCAP_ATOMIC property means that all writes of 569** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 570** mean that writes of blocks that are nnn bytes in size and 571** are aligned to an address which is an integer multiple of 572** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 573** that when data is appended to a file, the data is appended 574** first then the size of the file is extended, never the other 575** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 576** information is written to disk in the same order as calls 577** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 578** after reboot following a crash or power loss, the only bytes in a 579** file that were written at the application level might have changed 580** and that adjacent bytes, even bytes within the same sector are 581** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 582** flag indicates that a file cannot be deleted when open. The 583** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 584** read-only media and cannot be changed even by processes with 585** elevated privileges. 586** 587** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying 588** filesystem supports doing multiple write operations atomically when those 589** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and 590** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. 591*/ 592#define SQLITE_IOCAP_ATOMIC 0x00000001 593#define SQLITE_IOCAP_ATOMIC512 0x00000002 594#define SQLITE_IOCAP_ATOMIC1K 0x00000004 595#define SQLITE_IOCAP_ATOMIC2K 0x00000008 596#define SQLITE_IOCAP_ATOMIC4K 0x00000010 597#define SQLITE_IOCAP_ATOMIC8K 0x00000020 598#define SQLITE_IOCAP_ATOMIC16K 0x00000040 599#define SQLITE_IOCAP_ATOMIC32K 0x00000080 600#define SQLITE_IOCAP_ATOMIC64K 0x00000100 601#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 602#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 603#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 604#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 605#define SQLITE_IOCAP_IMMUTABLE 0x00002000 606#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000 607 608/* 609** CAPI3REF: File Locking Levels 610** 611** SQLite uses one of these integer values as the second 612** argument to calls it makes to the xLock() and xUnlock() methods 613** of an [sqlite3_io_methods] object. 614*/ 615#define SQLITE_LOCK_NONE 0 616#define SQLITE_LOCK_SHARED 1 617#define SQLITE_LOCK_RESERVED 2 618#define SQLITE_LOCK_PENDING 3 619#define SQLITE_LOCK_EXCLUSIVE 4 620 621/* 622** CAPI3REF: Synchronization Type Flags 623** 624** When SQLite invokes the xSync() method of an 625** [sqlite3_io_methods] object it uses a combination of 626** these integer values as the second argument. 627** 628** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 629** sync operation only needs to flush data to mass storage. Inode 630** information need not be flushed. If the lower four bits of the flag 631** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 632** If the lower four bits equal SQLITE_SYNC_FULL, that means 633** to use Mac OS X style fullsync instead of fsync(). 634** 635** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 636** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 637** settings. The [synchronous pragma] determines when calls to the 638** xSync VFS method occur and applies uniformly across all platforms. 639** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 640** energetic or rigorous or forceful the sync operations are and 641** only make a difference on Mac OSX for the default SQLite code. 642** (Third-party VFS implementations might also make the distinction 643** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 644** operating systems natively supported by SQLite, only Mac OSX 645** cares about the difference.) 646*/ 647#define SQLITE_SYNC_NORMAL 0x00002 648#define SQLITE_SYNC_FULL 0x00003 649#define SQLITE_SYNC_DATAONLY 0x00010 650 651/* 652** CAPI3REF: OS Interface Open File Handle 653** 654** An [sqlite3_file] object represents an open file in the 655** [sqlite3_vfs | OS interface layer]. Individual OS interface 656** implementations will 657** want to subclass this object by appending additional fields 658** for their own use. The pMethods entry is a pointer to an 659** [sqlite3_io_methods] object that defines methods for performing 660** I/O operations on the open file. 661*/ 662typedef struct sqlite3_file sqlite3_file; 663struct sqlite3_file { 664 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 665}; 666 667/* 668** CAPI3REF: OS Interface File Virtual Methods Object 669** 670** Every file opened by the [sqlite3_vfs.xOpen] method populates an 671** [sqlite3_file] object (or, more commonly, a subclass of the 672** [sqlite3_file] object) with a pointer to an instance of this object. 673** This object defines the methods used to perform various operations 674** against the open file represented by the [sqlite3_file] object. 675** 676** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 677** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 678** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 679** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 680** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 681** to NULL. 682** 683** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 684** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 685** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 686** flag may be ORed in to indicate that only the data of the file 687** and not its inode needs to be synced. 688** 689** The integer values to xLock() and xUnlock() are one of 690** <ul> 691** <li> [SQLITE_LOCK_NONE], 692** <li> [SQLITE_LOCK_SHARED], 693** <li> [SQLITE_LOCK_RESERVED], 694** <li> [SQLITE_LOCK_PENDING], or 695** <li> [SQLITE_LOCK_EXCLUSIVE]. 696** </ul> 697** xLock() increases the lock. xUnlock() decreases the lock. 698** The xCheckReservedLock() method checks whether any database connection, 699** either in this process or in some other process, is holding a RESERVED, 700** PENDING, or EXCLUSIVE lock on the file. It returns true 701** if such a lock exists and false otherwise. 702** 703** The xFileControl() method is a generic interface that allows custom 704** VFS implementations to directly control an open file using the 705** [sqlite3_file_control()] interface. The second "op" argument is an 706** integer opcode. The third argument is a generic pointer intended to 707** point to a structure that may contain arguments or space in which to 708** write return values. Potential uses for xFileControl() might be 709** functions to enable blocking locks with timeouts, to change the 710** locking strategy (for example to use dot-file locks), to inquire 711** about the status of a lock, or to break stale locks. The SQLite 712** core reserves all opcodes less than 100 for its own use. 713** A [file control opcodes | list of opcodes] less than 100 is available. 714** Applications that define a custom xFileControl method should use opcodes 715** greater than 100 to avoid conflicts. VFS implementations should 716** return [SQLITE_NOTFOUND] for file control opcodes that they do not 717** recognize. 718** 719** The xSectorSize() method returns the sector size of the 720** device that underlies the file. The sector size is the 721** minimum write that can be performed without disturbing 722** other bytes in the file. The xDeviceCharacteristics() 723** method returns a bit vector describing behaviors of the 724** underlying device: 725** 726** <ul> 727** <li> [SQLITE_IOCAP_ATOMIC] 728** <li> [SQLITE_IOCAP_ATOMIC512] 729** <li> [SQLITE_IOCAP_ATOMIC1K] 730** <li> [SQLITE_IOCAP_ATOMIC2K] 731** <li> [SQLITE_IOCAP_ATOMIC4K] 732** <li> [SQLITE_IOCAP_ATOMIC8K] 733** <li> [SQLITE_IOCAP_ATOMIC16K] 734** <li> [SQLITE_IOCAP_ATOMIC32K] 735** <li> [SQLITE_IOCAP_ATOMIC64K] 736** <li> [SQLITE_IOCAP_SAFE_APPEND] 737** <li> [SQLITE_IOCAP_SEQUENTIAL] 738** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN] 739** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE] 740** <li> [SQLITE_IOCAP_IMMUTABLE] 741** <li> [SQLITE_IOCAP_BATCH_ATOMIC] 742** </ul> 743** 744** The SQLITE_IOCAP_ATOMIC property means that all writes of 745** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 746** mean that writes of blocks that are nnn bytes in size and 747** are aligned to an address which is an integer multiple of 748** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 749** that when data is appended to a file, the data is appended 750** first then the size of the file is extended, never the other 751** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 752** information is written to disk in the same order as calls 753** to xWrite(). 754** 755** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 756** in the unread portions of the buffer with zeros. A VFS that 757** fails to zero-fill short reads might seem to work. However, 758** failure to zero-fill short reads will eventually lead to 759** database corruption. 760*/ 761typedef struct sqlite3_io_methods sqlite3_io_methods; 762struct sqlite3_io_methods { 763 int iVersion; 764 int (*xClose)(sqlite3_file*); 765 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 766 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 767 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 768 int (*xSync)(sqlite3_file*, int flags); 769 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 770 int (*xLock)(sqlite3_file*, int); 771 int (*xUnlock)(sqlite3_file*, int); 772 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 773 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 774 int (*xSectorSize)(sqlite3_file*); 775 int (*xDeviceCharacteristics)(sqlite3_file*); 776 /* Methods above are valid for version 1 */ 777 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 778 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 779 void (*xShmBarrier)(sqlite3_file*); 780 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 781 /* Methods above are valid for version 2 */ 782 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 783 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 784 /* Methods above are valid for version 3 */ 785 /* Additional methods may be added in future releases */ 786}; 787 788/* 789** CAPI3REF: Standard File Control Opcodes 790** KEYWORDS: {file control opcodes} {file control opcode} 791** 792** These integer constants are opcodes for the xFileControl method 793** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 794** interface. 795** 796** <ul> 797** <li>[[SQLITE_FCNTL_LOCKSTATE]] 798** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 799** opcode causes the xFileControl method to write the current state of 800** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 801** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 802** into an integer that the pArg argument points to. This capability 803** is used during testing and is only available when the SQLITE_TEST 804** compile-time option is used. 805** 806** <li>[[SQLITE_FCNTL_SIZE_HINT]] 807** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 808** layer a hint of how large the database file will grow to be during the 809** current transaction. This hint is not guaranteed to be accurate but it 810** is often close. The underlying VFS might choose to preallocate database 811** file space based on this hint in order to help writes to the database 812** file run faster. 813** 814** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 815** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 816** extends and truncates the database file in chunks of a size specified 817** by the user. The fourth argument to [sqlite3_file_control()] should 818** point to an integer (type int) containing the new chunk-size to use 819** for the nominated database. Allocating database file space in large 820** chunks (say 1MB at a time), may reduce file-system fragmentation and 821** improve performance on some systems. 822** 823** <li>[[SQLITE_FCNTL_FILE_POINTER]] 824** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 825** to the [sqlite3_file] object associated with a particular database 826** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER]. 827** 828** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]] 829** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer 830** to the [sqlite3_file] object associated with the journal file (either 831** the [rollback journal] or the [write-ahead log]) for a particular database 832** connection. See also [SQLITE_FCNTL_FILE_POINTER]. 833** 834** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 835** No longer in use. 836** 837** <li>[[SQLITE_FCNTL_SYNC]] 838** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 839** sent to the VFS immediately before the xSync method is invoked on a 840** database file descriptor. Or, if the xSync method is not invoked 841** because the user has configured SQLite with 842** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 843** of the xSync method. In most cases, the pointer argument passed with 844** this file-control is NULL. However, if the database file is being synced 845** as part of a multi-database commit, the argument points to a nul-terminated 846** string containing the transactions master-journal file name. VFSes that 847** do not need this signal should silently ignore this opcode. Applications 848** should not call [sqlite3_file_control()] with this opcode as doing so may 849** disrupt the operation of the specialized VFSes that do require it. 850** 851** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 852** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 853** and sent to the VFS after a transaction has been committed immediately 854** but before the database is unlocked. VFSes that do not need this signal 855** should silently ignore this opcode. Applications should not call 856** [sqlite3_file_control()] with this opcode as doing so may disrupt the 857** operation of the specialized VFSes that do require it. 858** 859** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 860** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 861** retry counts and intervals for certain disk I/O operations for the 862** windows [VFS] in order to provide robustness in the presence of 863** anti-virus programs. By default, the windows VFS will retry file read, 864** file write, and file delete operations up to 10 times, with a delay 865** of 25 milliseconds before the first retry and with the delay increasing 866** by an additional 25 milliseconds with each subsequent retry. This 867** opcode allows these two values (10 retries and 25 milliseconds of delay) 868** to be adjusted. The values are changed for all database connections 869** within the same process. The argument is a pointer to an array of two 870** integers where the first integer is the new retry count and the second 871** integer is the delay. If either integer is negative, then the setting 872** is not changed but instead the prior value of that setting is written 873** into the array entry, allowing the current retry settings to be 874** interrogated. The zDbName parameter is ignored. 875** 876** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 877** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 878** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 879** write ahead log and shared memory files used for transaction control 880** are automatically deleted when the latest connection to the database 881** closes. Setting persistent WAL mode causes those files to persist after 882** close. Persisting the files is useful when other processes that do not 883** have write permission on the directory containing the database file want 884** to read the database file, as the WAL and shared memory files must exist 885** in order for the database to be readable. The fourth parameter to 886** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 887** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 888** WAL mode. If the integer is -1, then it is overwritten with the current 889** WAL persistence setting. 890** 891** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 892** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 893** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 894** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 895** xDeviceCharacteristics methods. The fourth parameter to 896** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 897** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 898** mode. If the integer is -1, then it is overwritten with the current 899** zero-damage mode setting. 900** 901** <li>[[SQLITE_FCNTL_OVERWRITE]] 902** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 903** a write transaction to indicate that, unless it is rolled back for some 904** reason, the entire database file will be overwritten by the current 905** transaction. This is used by VACUUM operations. 906** 907** <li>[[SQLITE_FCNTL_VFSNAME]] 908** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 909** all [VFSes] in the VFS stack. The names are of all VFS shims and the 910** final bottom-level VFS are written into memory obtained from 911** [sqlite3_malloc()] and the result is stored in the char* variable 912** that the fourth parameter of [sqlite3_file_control()] points to. 913** The caller is responsible for freeing the memory when done. As with 914** all file-control actions, there is no guarantee that this will actually 915** do anything. Callers should initialize the char* variable to a NULL 916** pointer in case this file-control is not implemented. This file-control 917** is intended for diagnostic use only. 918** 919** <li>[[SQLITE_FCNTL_VFS_POINTER]] 920** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 921** [VFSes] currently in use. ^(The argument X in 922** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 923** of type "[sqlite3_vfs] **". This opcodes will set *X 924** to a pointer to the top-level VFS.)^ 925** ^When there are multiple VFS shims in the stack, this opcode finds the 926** upper-most shim only. 927** 928** <li>[[SQLITE_FCNTL_PRAGMA]] 929** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 930** file control is sent to the open [sqlite3_file] object corresponding 931** to the database file to which the pragma statement refers. ^The argument 932** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 933** pointers to strings (char**) in which the second element of the array 934** is the name of the pragma and the third element is the argument to the 935** pragma or NULL if the pragma has no argument. ^The handler for an 936** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 937** of the char** argument point to a string obtained from [sqlite3_mprintf()] 938** or the equivalent and that string will become the result of the pragma or 939** the error message if the pragma fails. ^If the 940** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 941** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 942** file control returns [SQLITE_OK], then the parser assumes that the 943** VFS has handled the PRAGMA itself and the parser generates a no-op 944** prepared statement if result string is NULL, or that returns a copy 945** of the result string if the string is non-NULL. 946** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 947** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 948** that the VFS encountered an error while handling the [PRAGMA] and the 949** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 950** file control occurs at the beginning of pragma statement analysis and so 951** it is able to override built-in [PRAGMA] statements. 952** 953** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 954** ^The [SQLITE_FCNTL_BUSYHANDLER] 955** file-control may be invoked by SQLite on the database file handle 956** shortly after it is opened in order to provide a custom VFS with access 957** to the connections busy-handler callback. The argument is of type (void **) 958** - an array of two (void *) values. The first (void *) actually points 959** to a function of type (int (*)(void *)). In order to invoke the connections 960** busy-handler, this function should be invoked with the second (void *) in 961** the array as the only argument. If it returns non-zero, then the operation 962** should be retried. If it returns zero, the custom VFS should abandon the 963** current operation. 964** 965** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 966** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 967** to have SQLite generate a 968** temporary filename using the same algorithm that is followed to generate 969** temporary filenames for TEMP tables and other internal uses. The 970** argument should be a char** which will be filled with the filename 971** written into memory obtained from [sqlite3_malloc()]. The caller should 972** invoke [sqlite3_free()] on the result to avoid a memory leak. 973** 974** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 975** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 976** maximum number of bytes that will be used for memory-mapped I/O. 977** The argument is a pointer to a value of type sqlite3_int64 that 978** is an advisory maximum number of bytes in the file to memory map. The 979** pointer is overwritten with the old value. The limit is not changed if 980** the value originally pointed to is negative, and so the current limit 981** can be queried by passing in a pointer to a negative number. This 982** file-control is used internally to implement [PRAGMA mmap_size]. 983** 984** <li>[[SQLITE_FCNTL_TRACE]] 985** The [SQLITE_FCNTL_TRACE] file control provides advisory information 986** to the VFS about what the higher layers of the SQLite stack are doing. 987** This file control is used by some VFS activity tracing [shims]. 988** The argument is a zero-terminated string. Higher layers in the 989** SQLite stack may generate instances of this file control if 990** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 991** 992** <li>[[SQLITE_FCNTL_HAS_MOVED]] 993** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 994** pointer to an integer and it writes a boolean into that integer depending 995** on whether or not the file has been renamed, moved, or deleted since it 996** was first opened. 997** 998** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]] 999** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the 1000** underlying native file handle associated with a file handle. This file 1001** control interprets its argument as a pointer to a native file handle and 1002** writes the resulting value there. 1003** 1004** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 1005** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 1006** opcode causes the xFileControl method to swap the file handle with the one 1007** pointed to by the pArg argument. This capability is used during testing 1008** and only needs to be supported when SQLITE_TEST is defined. 1009** 1010** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 1011** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 1012** be advantageous to block on the next WAL lock if the lock is not immediately 1013** available. The WAL subsystem issues this signal during rare 1014** circumstances in order to fix a problem with priority inversion. 1015** Applications should <em>not</em> use this file-control. 1016** 1017** <li>[[SQLITE_FCNTL_ZIPVFS]] 1018** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 1019** VFS should return SQLITE_NOTFOUND for this opcode. 1020** 1021** <li>[[SQLITE_FCNTL_RBU]] 1022** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 1023** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 1024** this opcode. 1025** 1026** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]] 1027** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then 1028** the file descriptor is placed in "batch write mode", which 1029** means all subsequent write operations will be deferred and done 1030** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems 1031** that do not support batch atomic writes will return SQLITE_NOTFOUND. 1032** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to 1033** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or 1034** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make 1035** no VFS interface calls on the same [sqlite3_file] file descriptor 1036** except for calls to the xWrite method and the xFileControl method 1037** with [SQLITE_FCNTL_SIZE_HINT]. 1038** 1039** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]] 1040** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write 1041** operations since the previous successful call to 1042** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically. 1043** This file control returns [SQLITE_OK] if and only if the writes were 1044** all performed successfully and have been committed to persistent storage. 1045** ^Regardless of whether or not it is successful, this file control takes 1046** the file descriptor out of batch write mode so that all subsequent 1047** write operations are independent. 1048** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without 1049** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1050** 1051** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]] 1052** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write 1053** operations since the previous successful call to 1054** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back. 1055** ^This file control takes the file descriptor out of batch write mode 1056** so that all subsequent write operations are independent. 1057** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without 1058** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1059** </ul> 1060*/ 1061#define SQLITE_FCNTL_LOCKSTATE 1 1062#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1063#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1064#define SQLITE_FCNTL_LAST_ERRNO 4 1065#define SQLITE_FCNTL_SIZE_HINT 5 1066#define SQLITE_FCNTL_CHUNK_SIZE 6 1067#define SQLITE_FCNTL_FILE_POINTER 7 1068#define SQLITE_FCNTL_SYNC_OMITTED 8 1069#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1070#define SQLITE_FCNTL_PERSIST_WAL 10 1071#define SQLITE_FCNTL_OVERWRITE 11 1072#define SQLITE_FCNTL_VFSNAME 12 1073#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1074#define SQLITE_FCNTL_PRAGMA 14 1075#define SQLITE_FCNTL_BUSYHANDLER 15 1076#define SQLITE_FCNTL_TEMPFILENAME 16 1077#define SQLITE_FCNTL_MMAP_SIZE 18 1078#define SQLITE_FCNTL_TRACE 19 1079#define SQLITE_FCNTL_HAS_MOVED 20 1080#define SQLITE_FCNTL_SYNC 21 1081#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1082#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1083#define SQLITE_FCNTL_WAL_BLOCK 24 1084#define SQLITE_FCNTL_ZIPVFS 25 1085#define SQLITE_FCNTL_RBU 26 1086#define SQLITE_FCNTL_VFS_POINTER 27 1087#define SQLITE_FCNTL_JOURNAL_POINTER 28 1088#define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1089#define SQLITE_FCNTL_PDB 30 1090#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31 1091#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32 1092#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33 1093 1094/* deprecated names */ 1095#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1096#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1097#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1098 1099 1100/* 1101** CAPI3REF: Mutex Handle 1102** 1103** The mutex module within SQLite defines [sqlite3_mutex] to be an 1104** abstract type for a mutex object. The SQLite core never looks 1105** at the internal representation of an [sqlite3_mutex]. It only 1106** deals with pointers to the [sqlite3_mutex] object. 1107** 1108** Mutexes are created using [sqlite3_mutex_alloc()]. 1109*/ 1110typedef struct sqlite3_mutex sqlite3_mutex; 1111 1112/* 1113** CAPI3REF: Loadable Extension Thunk 1114** 1115** A pointer to the opaque sqlite3_api_routines structure is passed as 1116** the third parameter to entry points of [loadable extensions]. This 1117** structure must be typedefed in order to work around compiler warnings 1118** on some platforms. 1119*/ 1120typedef struct sqlite3_api_routines sqlite3_api_routines; 1121 1122/* 1123** CAPI3REF: OS Interface Object 1124** 1125** An instance of the sqlite3_vfs object defines the interface between 1126** the SQLite core and the underlying operating system. The "vfs" 1127** in the name of the object stands for "virtual file system". See 1128** the [VFS | VFS documentation] for further information. 1129** 1130** The value of the iVersion field is initially 1 but may be larger in 1131** future versions of SQLite. Additional fields may be appended to this 1132** object when the iVersion value is increased. Note that the structure 1133** of the sqlite3_vfs object changes in the transaction between 1134** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 1135** modified. 1136** 1137** The szOsFile field is the size of the subclassed [sqlite3_file] 1138** structure used by this VFS. mxPathname is the maximum length of 1139** a pathname in this VFS. 1140** 1141** Registered sqlite3_vfs objects are kept on a linked list formed by 1142** the pNext pointer. The [sqlite3_vfs_register()] 1143** and [sqlite3_vfs_unregister()] interfaces manage this list 1144** in a thread-safe way. The [sqlite3_vfs_find()] interface 1145** searches the list. Neither the application code nor the VFS 1146** implementation should use the pNext pointer. 1147** 1148** The pNext field is the only field in the sqlite3_vfs 1149** structure that SQLite will ever modify. SQLite will only access 1150** or modify this field while holding a particular static mutex. 1151** The application should never modify anything within the sqlite3_vfs 1152** object once the object has been registered. 1153** 1154** The zName field holds the name of the VFS module. The name must 1155** be unique across all VFS modules. 1156** 1157** [[sqlite3_vfs.xOpen]] 1158** ^SQLite guarantees that the zFilename parameter to xOpen 1159** is either a NULL pointer or string obtained 1160** from xFullPathname() with an optional suffix added. 1161** ^If a suffix is added to the zFilename parameter, it will 1162** consist of a single "-" character followed by no more than 1163** 11 alphanumeric and/or "-" characters. 1164** ^SQLite further guarantees that 1165** the string will be valid and unchanged until xClose() is 1166** called. Because of the previous sentence, 1167** the [sqlite3_file] can safely store a pointer to the 1168** filename if it needs to remember the filename for some reason. 1169** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1170** must invent its own temporary name for the file. ^Whenever the 1171** xFilename parameter is NULL it will also be the case that the 1172** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1173** 1174** The flags argument to xOpen() includes all bits set in 1175** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1176** or [sqlite3_open16()] is used, then flags includes at least 1177** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1178** If xOpen() opens a file read-only then it sets *pOutFlags to 1179** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1180** 1181** ^(SQLite will also add one of the following flags to the xOpen() 1182** call, depending on the object being opened: 1183** 1184** <ul> 1185** <li> [SQLITE_OPEN_MAIN_DB] 1186** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1187** <li> [SQLITE_OPEN_TEMP_DB] 1188** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1189** <li> [SQLITE_OPEN_TRANSIENT_DB] 1190** <li> [SQLITE_OPEN_SUBJOURNAL] 1191** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1192** <li> [SQLITE_OPEN_WAL] 1193** </ul>)^ 1194** 1195** The file I/O implementation can use the object type flags to 1196** change the way it deals with files. For example, an application 1197** that does not care about crash recovery or rollback might make 1198** the open of a journal file a no-op. Writes to this journal would 1199** also be no-ops, and any attempt to read the journal would return 1200** SQLITE_IOERR. Or the implementation might recognize that a database 1201** file will be doing page-aligned sector reads and writes in a random 1202** order and set up its I/O subsystem accordingly. 1203** 1204** SQLite might also add one of the following flags to the xOpen method: 1205** 1206** <ul> 1207** <li> [SQLITE_OPEN_DELETEONCLOSE] 1208** <li> [SQLITE_OPEN_EXCLUSIVE] 1209** </ul> 1210** 1211** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1212** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1213** will be set for TEMP databases and their journals, transient 1214** databases, and subjournals. 1215** 1216** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1217** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1218** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1219** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1220** SQLITE_OPEN_CREATE, is used to indicate that file should always 1221** be created, and that it is an error if it already exists. 1222** It is <i>not</i> used to indicate the file should be opened 1223** for exclusive access. 1224** 1225** ^At least szOsFile bytes of memory are allocated by SQLite 1226** to hold the [sqlite3_file] structure passed as the third 1227** argument to xOpen. The xOpen method does not have to 1228** allocate the structure; it should just fill it in. Note that 1229** the xOpen method must set the sqlite3_file.pMethods to either 1230** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1231** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1232** element will be valid after xOpen returns regardless of the success 1233** or failure of the xOpen call. 1234** 1235** [[sqlite3_vfs.xAccess]] 1236** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1237** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1238** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1239** to test whether a file is at least readable. The file can be a 1240** directory. 1241** 1242** ^SQLite will always allocate at least mxPathname+1 bytes for the 1243** output buffer xFullPathname. The exact size of the output buffer 1244** is also passed as a parameter to both methods. If the output buffer 1245** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1246** handled as a fatal error by SQLite, vfs implementations should endeavor 1247** to prevent this by setting mxPathname to a sufficiently large value. 1248** 1249** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1250** interfaces are not strictly a part of the filesystem, but they are 1251** included in the VFS structure for completeness. 1252** The xRandomness() function attempts to return nBytes bytes 1253** of good-quality randomness into zOut. The return value is 1254** the actual number of bytes of randomness obtained. 1255** The xSleep() method causes the calling thread to sleep for at 1256** least the number of microseconds given. ^The xCurrentTime() 1257** method returns a Julian Day Number for the current date and time as 1258** a floating point value. 1259** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1260** Day Number multiplied by 86400000 (the number of milliseconds in 1261** a 24-hour day). 1262** ^SQLite will use the xCurrentTimeInt64() method to get the current 1263** date and time if that method is available (if iVersion is 2 or 1264** greater and the function pointer is not NULL) and will fall back 1265** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1266** 1267** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1268** are not used by the SQLite core. These optional interfaces are provided 1269** by some VFSes to facilitate testing of the VFS code. By overriding 1270** system calls with functions under its control, a test program can 1271** simulate faults and error conditions that would otherwise be difficult 1272** or impossible to induce. The set of system calls that can be overridden 1273** varies from one VFS to another, and from one version of the same VFS to the 1274** next. Applications that use these interfaces must be prepared for any 1275** or all of these interfaces to be NULL or for their behavior to change 1276** from one release to the next. Applications must not attempt to access 1277** any of these methods if the iVersion of the VFS is less than 3. 1278*/ 1279typedef struct sqlite3_vfs sqlite3_vfs; 1280typedef void (*sqlite3_syscall_ptr)(void); 1281struct sqlite3_vfs { 1282 int iVersion; /* Structure version number (currently 3) */ 1283 int szOsFile; /* Size of subclassed sqlite3_file */ 1284 int mxPathname; /* Maximum file pathname length */ 1285 sqlite3_vfs *pNext; /* Next registered VFS */ 1286 const char *zName; /* Name of this virtual file system */ 1287 void *pAppData; /* Pointer to application-specific data */ 1288 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1289 int flags, int *pOutFlags); 1290 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1291 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1292 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1293 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1294 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1295 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1296 void (*xDlClose)(sqlite3_vfs*, void*); 1297 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1298 int (*xSleep)(sqlite3_vfs*, int microseconds); 1299 int (*xCurrentTime)(sqlite3_vfs*, double*); 1300 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1301 /* 1302 ** The methods above are in version 1 of the sqlite_vfs object 1303 ** definition. Those that follow are added in version 2 or later 1304 */ 1305 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1306 /* 1307 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1308 ** Those below are for version 3 and greater. 1309 */ 1310 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1311 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1312 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1313 /* 1314 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1315 ** New fields may be appended in future versions. The iVersion 1316 ** value will increment whenever this happens. 1317 */ 1318}; 1319 1320/* 1321** CAPI3REF: Flags for the xAccess VFS method 1322** 1323** These integer constants can be used as the third parameter to 1324** the xAccess method of an [sqlite3_vfs] object. They determine 1325** what kind of permissions the xAccess method is looking for. 1326** With SQLITE_ACCESS_EXISTS, the xAccess method 1327** simply checks whether the file exists. 1328** With SQLITE_ACCESS_READWRITE, the xAccess method 1329** checks whether the named directory is both readable and writable 1330** (in other words, if files can be added, removed, and renamed within 1331** the directory). 1332** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1333** [temp_store_directory pragma], though this could change in a future 1334** release of SQLite. 1335** With SQLITE_ACCESS_READ, the xAccess method 1336** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1337** currently unused, though it might be used in a future release of 1338** SQLite. 1339*/ 1340#define SQLITE_ACCESS_EXISTS 0 1341#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1342#define SQLITE_ACCESS_READ 2 /* Unused */ 1343 1344/* 1345** CAPI3REF: Flags for the xShmLock VFS method 1346** 1347** These integer constants define the various locking operations 1348** allowed by the xShmLock method of [sqlite3_io_methods]. The 1349** following are the only legal combinations of flags to the 1350** xShmLock method: 1351** 1352** <ul> 1353** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1354** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1355** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1356** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1357** </ul> 1358** 1359** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1360** was given on the corresponding lock. 1361** 1362** The xShmLock method can transition between unlocked and SHARED or 1363** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1364** and EXCLUSIVE. 1365*/ 1366#define SQLITE_SHM_UNLOCK 1 1367#define SQLITE_SHM_LOCK 2 1368#define SQLITE_SHM_SHARED 4 1369#define SQLITE_SHM_EXCLUSIVE 8 1370 1371/* 1372** CAPI3REF: Maximum xShmLock index 1373** 1374** The xShmLock method on [sqlite3_io_methods] may use values 1375** between 0 and this upper bound as its "offset" argument. 1376** The SQLite core will never attempt to acquire or release a 1377** lock outside of this range 1378*/ 1379#define SQLITE_SHM_NLOCK 8 1380 1381 1382/* 1383** CAPI3REF: Initialize The SQLite Library 1384** 1385** ^The sqlite3_initialize() routine initializes the 1386** SQLite library. ^The sqlite3_shutdown() routine 1387** deallocates any resources that were allocated by sqlite3_initialize(). 1388** These routines are designed to aid in process initialization and 1389** shutdown on embedded systems. Workstation applications using 1390** SQLite normally do not need to invoke either of these routines. 1391** 1392** A call to sqlite3_initialize() is an "effective" call if it is 1393** the first time sqlite3_initialize() is invoked during the lifetime of 1394** the process, or if it is the first time sqlite3_initialize() is invoked 1395** following a call to sqlite3_shutdown(). ^(Only an effective call 1396** of sqlite3_initialize() does any initialization. All other calls 1397** are harmless no-ops.)^ 1398** 1399** A call to sqlite3_shutdown() is an "effective" call if it is the first 1400** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1401** an effective call to sqlite3_shutdown() does any deinitialization. 1402** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1403** 1404** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1405** is not. The sqlite3_shutdown() interface must only be called from a 1406** single thread. All open [database connections] must be closed and all 1407** other SQLite resources must be deallocated prior to invoking 1408** sqlite3_shutdown(). 1409** 1410** Among other things, ^sqlite3_initialize() will invoke 1411** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1412** will invoke sqlite3_os_end(). 1413** 1414** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1415** ^If for some reason, sqlite3_initialize() is unable to initialize 1416** the library (perhaps it is unable to allocate a needed resource such 1417** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1418** 1419** ^The sqlite3_initialize() routine is called internally by many other 1420** SQLite interfaces so that an application usually does not need to 1421** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1422** calls sqlite3_initialize() so the SQLite library will be automatically 1423** initialized when [sqlite3_open()] is called if it has not be initialized 1424** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1425** compile-time option, then the automatic calls to sqlite3_initialize() 1426** are omitted and the application must call sqlite3_initialize() directly 1427** prior to using any other SQLite interface. For maximum portability, 1428** it is recommended that applications always invoke sqlite3_initialize() 1429** directly prior to using any other SQLite interface. Future releases 1430** of SQLite may require this. In other words, the behavior exhibited 1431** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1432** default behavior in some future release of SQLite. 1433** 1434** The sqlite3_os_init() routine does operating-system specific 1435** initialization of the SQLite library. The sqlite3_os_end() 1436** routine undoes the effect of sqlite3_os_init(). Typical tasks 1437** performed by these routines include allocation or deallocation 1438** of static resources, initialization of global variables, 1439** setting up a default [sqlite3_vfs] module, or setting up 1440** a default configuration using [sqlite3_config()]. 1441** 1442** The application should never invoke either sqlite3_os_init() 1443** or sqlite3_os_end() directly. The application should only invoke 1444** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1445** interface is called automatically by sqlite3_initialize() and 1446** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1447** implementations for sqlite3_os_init() and sqlite3_os_end() 1448** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1449** When [custom builds | built for other platforms] 1450** (using the [SQLITE_OS_OTHER=1] compile-time 1451** option) the application must supply a suitable implementation for 1452** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1453** implementation of sqlite3_os_init() or sqlite3_os_end() 1454** must return [SQLITE_OK] on success and some other [error code] upon 1455** failure. 1456*/ 1457int sqlite3_initialize(void); 1458int sqlite3_shutdown(void); 1459int sqlite3_os_init(void); 1460int sqlite3_os_end(void); 1461 1462/* 1463** CAPI3REF: Configuring The SQLite Library 1464** 1465** The sqlite3_config() interface is used to make global configuration 1466** changes to SQLite in order to tune SQLite to the specific needs of 1467** the application. The default configuration is recommended for most 1468** applications and so this routine is usually not necessary. It is 1469** provided to support rare applications with unusual needs. 1470** 1471** <b>The sqlite3_config() interface is not threadsafe. The application 1472** must ensure that no other SQLite interfaces are invoked by other 1473** threads while sqlite3_config() is running.</b> 1474** 1475** The sqlite3_config() interface 1476** may only be invoked prior to library initialization using 1477** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1478** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1479** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1480** Note, however, that ^sqlite3_config() can be called as part of the 1481** implementation of an application-defined [sqlite3_os_init()]. 1482** 1483** The first argument to sqlite3_config() is an integer 1484** [configuration option] that determines 1485** what property of SQLite is to be configured. Subsequent arguments 1486** vary depending on the [configuration option] 1487** in the first argument. 1488** 1489** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1490** ^If the option is unknown or SQLite is unable to set the option 1491** then this routine returns a non-zero [error code]. 1492*/ 1493int sqlite3_config(int, ...); 1494 1495/* 1496** CAPI3REF: Configure database connections 1497** METHOD: sqlite3 1498** 1499** The sqlite3_db_config() interface is used to make configuration 1500** changes to a [database connection]. The interface is similar to 1501** [sqlite3_config()] except that the changes apply to a single 1502** [database connection] (specified in the first argument). 1503** 1504** The second argument to sqlite3_db_config(D,V,...) is the 1505** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1506** that indicates what aspect of the [database connection] is being configured. 1507** Subsequent arguments vary depending on the configuration verb. 1508** 1509** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1510** the call is considered successful. 1511*/ 1512int sqlite3_db_config(sqlite3*, int op, ...); 1513 1514/* 1515** CAPI3REF: Memory Allocation Routines 1516** 1517** An instance of this object defines the interface between SQLite 1518** and low-level memory allocation routines. 1519** 1520** This object is used in only one place in the SQLite interface. 1521** A pointer to an instance of this object is the argument to 1522** [sqlite3_config()] when the configuration option is 1523** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1524** By creating an instance of this object 1525** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1526** during configuration, an application can specify an alternative 1527** memory allocation subsystem for SQLite to use for all of its 1528** dynamic memory needs. 1529** 1530** Note that SQLite comes with several [built-in memory allocators] 1531** that are perfectly adequate for the overwhelming majority of applications 1532** and that this object is only useful to a tiny minority of applications 1533** with specialized memory allocation requirements. This object is 1534** also used during testing of SQLite in order to specify an alternative 1535** memory allocator that simulates memory out-of-memory conditions in 1536** order to verify that SQLite recovers gracefully from such 1537** conditions. 1538** 1539** The xMalloc, xRealloc, and xFree methods must work like the 1540** malloc(), realloc() and free() functions from the standard C library. 1541** ^SQLite guarantees that the second argument to 1542** xRealloc is always a value returned by a prior call to xRoundup. 1543** 1544** xSize should return the allocated size of a memory allocation 1545** previously obtained from xMalloc or xRealloc. The allocated size 1546** is always at least as big as the requested size but may be larger. 1547** 1548** The xRoundup method returns what would be the allocated size of 1549** a memory allocation given a particular requested size. Most memory 1550** allocators round up memory allocations at least to the next multiple 1551** of 8. Some allocators round up to a larger multiple or to a power of 2. 1552** Every memory allocation request coming in through [sqlite3_malloc()] 1553** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1554** that causes the corresponding memory allocation to fail. 1555** 1556** The xInit method initializes the memory allocator. For example, 1557** it might allocate any require mutexes or initialize internal data 1558** structures. The xShutdown method is invoked (indirectly) by 1559** [sqlite3_shutdown()] and should deallocate any resources acquired 1560** by xInit. The pAppData pointer is used as the only parameter to 1561** xInit and xShutdown. 1562** 1563** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1564** the xInit method, so the xInit method need not be threadsafe. The 1565** xShutdown method is only called from [sqlite3_shutdown()] so it does 1566** not need to be threadsafe either. For all other methods, SQLite 1567** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1568** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1569** it is by default) and so the methods are automatically serialized. 1570** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1571** methods must be threadsafe or else make their own arrangements for 1572** serialization. 1573** 1574** SQLite will never invoke xInit() more than once without an intervening 1575** call to xShutdown(). 1576*/ 1577typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1578struct sqlite3_mem_methods { 1579 void *(*xMalloc)(int); /* Memory allocation function */ 1580 void (*xFree)(void*); /* Free a prior allocation */ 1581 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1582 int (*xSize)(void*); /* Return the size of an allocation */ 1583 int (*xRoundup)(int); /* Round up request size to allocation size */ 1584 int (*xInit)(void*); /* Initialize the memory allocator */ 1585 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1586 void *pAppData; /* Argument to xInit() and xShutdown() */ 1587}; 1588 1589/* 1590** CAPI3REF: Configuration Options 1591** KEYWORDS: {configuration option} 1592** 1593** These constants are the available integer configuration options that 1594** can be passed as the first argument to the [sqlite3_config()] interface. 1595** 1596** New configuration options may be added in future releases of SQLite. 1597** Existing configuration options might be discontinued. Applications 1598** should check the return code from [sqlite3_config()] to make sure that 1599** the call worked. The [sqlite3_config()] interface will return a 1600** non-zero [error code] if a discontinued or unsupported configuration option 1601** is invoked. 1602** 1603** <dl> 1604** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1605** <dd>There are no arguments to this option. ^This option sets the 1606** [threading mode] to Single-thread. In other words, it disables 1607** all mutexing and puts SQLite into a mode where it can only be used 1608** by a single thread. ^If SQLite is compiled with 1609** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1610** it is not possible to change the [threading mode] from its default 1611** value of Single-thread and so [sqlite3_config()] will return 1612** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1613** configuration option.</dd> 1614** 1615** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1616** <dd>There are no arguments to this option. ^This option sets the 1617** [threading mode] to Multi-thread. In other words, it disables 1618** mutexing on [database connection] and [prepared statement] objects. 1619** The application is responsible for serializing access to 1620** [database connections] and [prepared statements]. But other mutexes 1621** are enabled so that SQLite will be safe to use in a multi-threaded 1622** environment as long as no two threads attempt to use the same 1623** [database connection] at the same time. ^If SQLite is compiled with 1624** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1625** it is not possible to set the Multi-thread [threading mode] and 1626** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1627** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1628** 1629** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1630** <dd>There are no arguments to this option. ^This option sets the 1631** [threading mode] to Serialized. In other words, this option enables 1632** all mutexes including the recursive 1633** mutexes on [database connection] and [prepared statement] objects. 1634** In this mode (which is the default when SQLite is compiled with 1635** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1636** to [database connections] and [prepared statements] so that the 1637** application is free to use the same [database connection] or the 1638** same [prepared statement] in different threads at the same time. 1639** ^If SQLite is compiled with 1640** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1641** it is not possible to set the Serialized [threading mode] and 1642** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1643** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1644** 1645** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1646** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1647** a pointer to an instance of the [sqlite3_mem_methods] structure. 1648** The argument specifies 1649** alternative low-level memory allocation routines to be used in place of 1650** the memory allocation routines built into SQLite.)^ ^SQLite makes 1651** its own private copy of the content of the [sqlite3_mem_methods] structure 1652** before the [sqlite3_config()] call returns.</dd> 1653** 1654** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1655** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1656** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1657** The [sqlite3_mem_methods] 1658** structure is filled with the currently defined memory allocation routines.)^ 1659** This option can be used to overload the default memory allocation 1660** routines with a wrapper that simulations memory allocation failure or 1661** tracks memory usage, for example. </dd> 1662** 1663** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1664** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1665** interpreted as a boolean, which enables or disables the collection of 1666** memory allocation statistics. ^(When memory allocation statistics are 1667** disabled, the following SQLite interfaces become non-operational: 1668** <ul> 1669** <li> [sqlite3_memory_used()] 1670** <li> [sqlite3_memory_highwater()] 1671** <li> [sqlite3_soft_heap_limit64()] 1672** <li> [sqlite3_status64()] 1673** </ul>)^ 1674** ^Memory allocation statistics are enabled by default unless SQLite is 1675** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1676** allocation statistics are disabled by default. 1677** </dd> 1678** 1679** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1680** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer 1681** that SQLite can use for scratch memory. ^(There are three arguments 1682** to SQLITE_CONFIG_SCRATCH: A pointer an 8-byte 1683** aligned memory buffer from which the scratch allocations will be 1684** drawn, the size of each scratch allocation (sz), 1685** and the maximum number of scratch allocations (N).)^ 1686** The first argument must be a pointer to an 8-byte aligned buffer 1687** of at least sz*N bytes of memory. 1688** ^SQLite will not use more than one scratch buffers per thread. 1689** ^SQLite will never request a scratch buffer that is more than 6 1690** times the database page size. 1691** ^If SQLite needs needs additional 1692** scratch memory beyond what is provided by this configuration option, then 1693** [sqlite3_malloc()] will be used to obtain the memory needed.<p> 1694** ^When the application provides any amount of scratch memory using 1695** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large 1696** [sqlite3_malloc|heap allocations]. 1697** This can help [Robson proof|prevent memory allocation failures] due to heap 1698** fragmentation in low-memory embedded systems. 1699** </dd> 1700** 1701** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1702** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1703** that SQLite can use for the database page cache with the default page 1704** cache implementation. 1705** This configuration option is a no-op if an application-define page 1706** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1707** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1708** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1709** and the number of cache lines (N). 1710** The sz argument should be the size of the largest database page 1711** (a power of two between 512 and 65536) plus some extra bytes for each 1712** page header. ^The number of extra bytes needed by the page header 1713** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1714** ^It is harmless, apart from the wasted memory, 1715** for the sz parameter to be larger than necessary. The pMem 1716** argument must be either a NULL pointer or a pointer to an 8-byte 1717** aligned block of memory of at least sz*N bytes, otherwise 1718** subsequent behavior is undefined. 1719** ^When pMem is not NULL, SQLite will strive to use the memory provided 1720** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1721** a page cache line is larger than sz bytes or if all of the pMem buffer 1722** is exhausted. 1723** ^If pMem is NULL and N is non-zero, then each database connection 1724** does an initial bulk allocation for page cache memory 1725** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1726** of -1024*N bytes if N is negative, . ^If additional 1727** page cache memory is needed beyond what is provided by the initial 1728** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1729** additional cache line. </dd> 1730** 1731** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1732** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1733** that SQLite will use for all of its dynamic memory allocation needs 1734** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and 1735** [SQLITE_CONFIG_PAGECACHE]. 1736** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1737** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1738** [SQLITE_ERROR] if invoked otherwise. 1739** ^There are three arguments to SQLITE_CONFIG_HEAP: 1740** An 8-byte aligned pointer to the memory, 1741** the number of bytes in the memory buffer, and the minimum allocation size. 1742** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1743** to using its default memory allocator (the system malloc() implementation), 1744** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1745** memory pointer is not NULL then the alternative memory 1746** allocator is engaged to handle all of SQLites memory allocation needs. 1747** The first pointer (the memory pointer) must be aligned to an 8-byte 1748** boundary or subsequent behavior of SQLite will be undefined. 1749** The minimum allocation size is capped at 2**12. Reasonable values 1750** for the minimum allocation size are 2**5 through 2**8.</dd> 1751** 1752** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1753** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1754** pointer to an instance of the [sqlite3_mutex_methods] structure. 1755** The argument specifies alternative low-level mutex routines to be used 1756** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1757** the content of the [sqlite3_mutex_methods] structure before the call to 1758** [sqlite3_config()] returns. ^If SQLite is compiled with 1759** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1760** the entire mutexing subsystem is omitted from the build and hence calls to 1761** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1762** return [SQLITE_ERROR].</dd> 1763** 1764** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1765** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1766** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1767** [sqlite3_mutex_methods] 1768** structure is filled with the currently defined mutex routines.)^ 1769** This option can be used to overload the default mutex allocation 1770** routines with a wrapper used to track mutex usage for performance 1771** profiling or testing, for example. ^If SQLite is compiled with 1772** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1773** the entire mutexing subsystem is omitted from the build and hence calls to 1774** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1775** return [SQLITE_ERROR].</dd> 1776** 1777** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1778** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1779** the default size of lookaside memory on each [database connection]. 1780** The first argument is the 1781** size of each lookaside buffer slot and the second is the number of 1782** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1783** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1784** option to [sqlite3_db_config()] can be used to change the lookaside 1785** configuration on individual connections.)^ </dd> 1786** 1787** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1788** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1789** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1790** the interface to a custom page cache implementation.)^ 1791** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1792** 1793** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1794** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1795** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1796** the current page cache implementation into that object.)^ </dd> 1797** 1798** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1799** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1800** global [error log]. 1801** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1802** function with a call signature of void(*)(void*,int,const char*), 1803** and a pointer to void. ^If the function pointer is not NULL, it is 1804** invoked by [sqlite3_log()] to process each logging event. ^If the 1805** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1806** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1807** passed through as the first parameter to the application-defined logger 1808** function whenever that function is invoked. ^The second parameter to 1809** the logger function is a copy of the first parameter to the corresponding 1810** [sqlite3_log()] call and is intended to be a [result code] or an 1811** [extended result code]. ^The third parameter passed to the logger is 1812** log message after formatting via [sqlite3_snprintf()]. 1813** The SQLite logging interface is not reentrant; the logger function 1814** supplied by the application must not invoke any SQLite interface. 1815** In a multi-threaded application, the application-defined logger 1816** function must be threadsafe. </dd> 1817** 1818** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1819** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1820** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1821** then URI handling is globally disabled.)^ ^If URI handling is globally 1822** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1823** [sqlite3_open16()] or 1824** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1825** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1826** connection is opened. ^If it is globally disabled, filenames are 1827** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1828** database connection is opened. ^(By default, URI handling is globally 1829** disabled. The default value may be changed by compiling with the 1830** [SQLITE_USE_URI] symbol defined.)^ 1831** 1832** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1833** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1834** argument which is interpreted as a boolean in order to enable or disable 1835** the use of covering indices for full table scans in the query optimizer. 1836** ^The default setting is determined 1837** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1838** if that compile-time option is omitted. 1839** The ability to disable the use of covering indices for full table scans 1840** is because some incorrectly coded legacy applications might malfunction 1841** when the optimization is enabled. Providing the ability to 1842** disable the optimization allows the older, buggy application code to work 1843** without change even with newer versions of SQLite. 1844** 1845** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1846** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1847** <dd> These options are obsolete and should not be used by new code. 1848** They are retained for backwards compatibility but are now no-ops. 1849** </dd> 1850** 1851** [[SQLITE_CONFIG_SQLLOG]] 1852** <dt>SQLITE_CONFIG_SQLLOG 1853** <dd>This option is only available if sqlite is compiled with the 1854** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1855** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1856** The second should be of type (void*). The callback is invoked by the library 1857** in three separate circumstances, identified by the value passed as the 1858** fourth parameter. If the fourth parameter is 0, then the database connection 1859** passed as the second argument has just been opened. The third argument 1860** points to a buffer containing the name of the main database file. If the 1861** fourth parameter is 1, then the SQL statement that the third parameter 1862** points to has just been executed. Or, if the fourth parameter is 2, then 1863** the connection being passed as the second parameter is being closed. The 1864** third parameter is passed NULL In this case. An example of using this 1865** configuration option can be seen in the "test_sqllog.c" source file in 1866** the canonical SQLite source tree.</dd> 1867** 1868** [[SQLITE_CONFIG_MMAP_SIZE]] 1869** <dt>SQLITE_CONFIG_MMAP_SIZE 1870** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1871** that are the default mmap size limit (the default setting for 1872** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1873** ^The default setting can be overridden by each database connection using 1874** either the [PRAGMA mmap_size] command, or by using the 1875** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1876** will be silently truncated if necessary so that it does not exceed the 1877** compile-time maximum mmap size set by the 1878** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1879** ^If either argument to this option is negative, then that argument is 1880** changed to its compile-time default. 1881** 1882** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1883** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1884** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1885** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1886** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1887** that specifies the maximum size of the created heap. 1888** 1889** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1890** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1891** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1892** is a pointer to an integer and writes into that integer the number of extra 1893** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1894** The amount of extra space required can change depending on the compiler, 1895** target platform, and SQLite version. 1896** 1897** [[SQLITE_CONFIG_PMASZ]] 1898** <dt>SQLITE_CONFIG_PMASZ 1899** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1900** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1901** sorter to that integer. The default minimum PMA Size is set by the 1902** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1903** to help with sort operations when multithreaded sorting 1904** is enabled (using the [PRAGMA threads] command) and the amount of content 1905** to be sorted exceeds the page size times the minimum of the 1906** [PRAGMA cache_size] setting and this value. 1907** 1908** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 1909** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 1910** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 1911** becomes the [statement journal] spill-to-disk threshold. 1912** [Statement journals] are held in memory until their size (in bytes) 1913** exceeds this threshold, at which point they are written to disk. 1914** Or if the threshold is -1, statement journals are always held 1915** exclusively in memory. 1916** Since many statement journals never become large, setting the spill 1917** threshold to a value such as 64KiB can greatly reduce the amount of 1918** I/O required to support statement rollback. 1919** The default value for this setting is controlled by the 1920** [SQLITE_STMTJRNL_SPILL] compile-time option. 1921** </dl> 1922*/ 1923#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1924#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1925#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1926#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1927#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1928#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1929#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1930#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1931#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1932#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1933#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1934/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1935#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1936#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1937#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1938#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1939#define SQLITE_CONFIG_URI 17 /* int */ 1940#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1941#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1942#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1943#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1944#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1945#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1946#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1947#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 1948#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 1949 1950/* 1951** CAPI3REF: Database Connection Configuration Options 1952** 1953** These constants are the available integer configuration options that 1954** can be passed as the second argument to the [sqlite3_db_config()] interface. 1955** 1956** New configuration options may be added in future releases of SQLite. 1957** Existing configuration options might be discontinued. Applications 1958** should check the return code from [sqlite3_db_config()] to make sure that 1959** the call worked. ^The [sqlite3_db_config()] interface will return a 1960** non-zero [error code] if a discontinued or unsupported configuration option 1961** is invoked. 1962** 1963** <dl> 1964** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1965** <dd> ^This option takes three additional arguments that determine the 1966** [lookaside memory allocator] configuration for the [database connection]. 1967** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1968** pointer to a memory buffer to use for lookaside memory. 1969** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1970** may be NULL in which case SQLite will allocate the 1971** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1972** size of each lookaside buffer slot. ^The third argument is the number of 1973** slots. The size of the buffer in the first argument must be greater than 1974** or equal to the product of the second and third arguments. The buffer 1975** must be aligned to an 8-byte boundary. ^If the second argument to 1976** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1977** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1978** configuration for a database connection can only be changed when that 1979** connection is not currently using lookaside memory, or in other words 1980** when the "current value" returned by 1981** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1982** Any attempt to change the lookaside memory configuration when lookaside 1983** memory is in use leaves the configuration unchanged and returns 1984** [SQLITE_BUSY].)^</dd> 1985** 1986** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1987** <dd> ^This option is used to enable or disable the enforcement of 1988** [foreign key constraints]. There should be two additional arguments. 1989** The first argument is an integer which is 0 to disable FK enforcement, 1990** positive to enable FK enforcement or negative to leave FK enforcement 1991** unchanged. The second parameter is a pointer to an integer into which 1992** is written 0 or 1 to indicate whether FK enforcement is off or on 1993** following this call. The second parameter may be a NULL pointer, in 1994** which case the FK enforcement setting is not reported back. </dd> 1995** 1996** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1997** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1998** There should be two additional arguments. 1999** The first argument is an integer which is 0 to disable triggers, 2000** positive to enable triggers or negative to leave the setting unchanged. 2001** The second parameter is a pointer to an integer into which 2002** is written 0 or 1 to indicate whether triggers are disabled or enabled 2003** following this call. The second parameter may be a NULL pointer, in 2004** which case the trigger setting is not reported back. </dd> 2005** 2006** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 2007** <dd> ^This option is used to enable or disable the two-argument 2008** version of the [fts3_tokenizer()] function which is part of the 2009** [FTS3] full-text search engine extension. 2010** There should be two additional arguments. 2011** The first argument is an integer which is 0 to disable fts3_tokenizer() or 2012** positive to enable fts3_tokenizer() or negative to leave the setting 2013** unchanged. 2014** The second parameter is a pointer to an integer into which 2015** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 2016** following this call. The second parameter may be a NULL pointer, in 2017** which case the new setting is not reported back. </dd> 2018** 2019** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 2020** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 2021** interface independently of the [load_extension()] SQL function. 2022** The [sqlite3_enable_load_extension()] API enables or disables both the 2023** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 2024** There should be two additional arguments. 2025** When the first argument to this interface is 1, then only the C-API is 2026** enabled and the SQL function remains disabled. If the first argument to 2027** this interface is 0, then both the C-API and the SQL function are disabled. 2028** If the first argument is -1, then no changes are made to state of either the 2029** C-API or the SQL function. 2030** The second parameter is a pointer to an integer into which 2031** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 2032** is disabled or enabled following this call. The second parameter may 2033** be a NULL pointer, in which case the new setting is not reported back. 2034** </dd> 2035** 2036** <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 2037** <dd> ^This option is used to change the name of the "main" database 2038** schema. ^The sole argument is a pointer to a constant UTF8 string 2039** which will become the new schema name in place of "main". ^SQLite 2040** does not make a copy of the new main schema name string, so the application 2041** must ensure that the argument passed into this DBCONFIG option is unchanged 2042** until after the database connection closes. 2043** </dd> 2044** 2045** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 2046** <dd> Usually, when a database in wal mode is closed or detached from a 2047** database handle, SQLite checks if this will mean that there are now no 2048** connections at all to the database. If so, it performs a checkpoint 2049** operation before closing the connection. This option may be used to 2050** override this behaviour. The first parameter passed to this operation 2051** is an integer - non-zero to disable checkpoints-on-close, or zero (the 2052** default) to enable them. The second parameter is a pointer to an integer 2053** into which is written 0 or 1 to indicate whether checkpoints-on-close 2054** have been disabled - 0 if they are not disabled, 1 if they are. 2055** </dd> 2056** 2057** <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2058** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2059** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2060** a single SQL query statement will always use the same algorithm regardless 2061** of values of [bound parameters].)^ The QPSG disables some query optimizations 2062** that look at the values of bound parameters, which can make some queries 2063** slower. But the QPSG has the advantage of more predictable behavior. With 2064** the QPSG active, SQLite will always use the same query plan in the field as 2065** was used during testing in the lab. 2066** </dd> 2067** 2068** </dl> 2069*/ 2070#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2071#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2072#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2073#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2074#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2075#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2076#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2077#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2078 2079 2080/* 2081** CAPI3REF: Enable Or Disable Extended Result Codes 2082** METHOD: sqlite3 2083** 2084** ^The sqlite3_extended_result_codes() routine enables or disables the 2085** [extended result codes] feature of SQLite. ^The extended result 2086** codes are disabled by default for historical compatibility. 2087*/ 2088int sqlite3_extended_result_codes(sqlite3*, int onoff); 2089 2090/* 2091** CAPI3REF: Last Insert Rowid 2092** METHOD: sqlite3 2093** 2094** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2095** has a unique 64-bit signed 2096** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2097** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2098** names are not also used by explicitly declared columns. ^If 2099** the table has a column of type [INTEGER PRIMARY KEY] then that column 2100** is another alias for the rowid. 2101** 2102** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2103** the most recent successful [INSERT] into a rowid table or [virtual table] 2104** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2105** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2106** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2107** zero. 2108** 2109** As well as being set automatically as rows are inserted into database 2110** tables, the value returned by this function may be set explicitly by 2111** [sqlite3_set_last_insert_rowid()] 2112** 2113** Some virtual table implementations may INSERT rows into rowid tables as 2114** part of committing a transaction (e.g. to flush data accumulated in memory 2115** to disk). In this case subsequent calls to this function return the rowid 2116** associated with these internal INSERT operations, which leads to 2117** unintuitive results. Virtual table implementations that do write to rowid 2118** tables in this way can avoid this problem by restoring the original 2119** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2120** control to the user. 2121** 2122** ^(If an [INSERT] occurs within a trigger then this routine will 2123** return the [rowid] of the inserted row as long as the trigger is 2124** running. Once the trigger program ends, the value returned 2125** by this routine reverts to what it was before the trigger was fired.)^ 2126** 2127** ^An [INSERT] that fails due to a constraint violation is not a 2128** successful [INSERT] and does not change the value returned by this 2129** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2130** and INSERT OR ABORT make no changes to the return value of this 2131** routine when their insertion fails. ^(When INSERT OR REPLACE 2132** encounters a constraint violation, it does not fail. The 2133** INSERT continues to completion after deleting rows that caused 2134** the constraint problem so INSERT OR REPLACE will always change 2135** the return value of this interface.)^ 2136** 2137** ^For the purposes of this routine, an [INSERT] is considered to 2138** be successful even if it is subsequently rolled back. 2139** 2140** This function is accessible to SQL statements via the 2141** [last_insert_rowid() SQL function]. 2142** 2143** If a separate thread performs a new [INSERT] on the same 2144** database connection while the [sqlite3_last_insert_rowid()] 2145** function is running and thus changes the last insert [rowid], 2146** then the value returned by [sqlite3_last_insert_rowid()] is 2147** unpredictable and might not equal either the old or the new 2148** last insert [rowid]. 2149*/ 2150sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2151 2152/* 2153** CAPI3REF: Set the Last Insert Rowid value. 2154** METHOD: sqlite3 2155** 2156** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2157** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2158** without inserting a row into the database. 2159*/ 2160void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2161 2162/* 2163** CAPI3REF: Count The Number Of Rows Modified 2164** METHOD: sqlite3 2165** 2166** ^This function returns the number of rows modified, inserted or 2167** deleted by the most recently completed INSERT, UPDATE or DELETE 2168** statement on the database connection specified by the only parameter. 2169** ^Executing any other type of SQL statement does not modify the value 2170** returned by this function. 2171** 2172** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2173** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2174** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2175** 2176** Changes to a view that are intercepted by 2177** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2178** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2179** DELETE statement run on a view is always zero. Only changes made to real 2180** tables are counted. 2181** 2182** Things are more complicated if the sqlite3_changes() function is 2183** executed while a trigger program is running. This may happen if the 2184** program uses the [changes() SQL function], or if some other callback 2185** function invokes sqlite3_changes() directly. Essentially: 2186** 2187** <ul> 2188** <li> ^(Before entering a trigger program the value returned by 2189** sqlite3_changes() function is saved. After the trigger program 2190** has finished, the original value is restored.)^ 2191** 2192** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2193** statement sets the value returned by sqlite3_changes() 2194** upon completion as normal. Of course, this value will not include 2195** any changes performed by sub-triggers, as the sqlite3_changes() 2196** value will be saved and restored after each sub-trigger has run.)^ 2197** </ul> 2198** 2199** ^This means that if the changes() SQL function (or similar) is used 2200** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2201** returns the value as set when the calling statement began executing. 2202** ^If it is used by the second or subsequent such statement within a trigger 2203** program, the value returned reflects the number of rows modified by the 2204** previous INSERT, UPDATE or DELETE statement within the same trigger. 2205** 2206** See also the [sqlite3_total_changes()] interface, the 2207** [count_changes pragma], and the [changes() SQL function]. 2208** 2209** If a separate thread makes changes on the same database connection 2210** while [sqlite3_changes()] is running then the value returned 2211** is unpredictable and not meaningful. 2212*/ 2213int sqlite3_changes(sqlite3*); 2214 2215/* 2216** CAPI3REF: Total Number Of Rows Modified 2217** METHOD: sqlite3 2218** 2219** ^This function returns the total number of rows inserted, modified or 2220** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2221** since the database connection was opened, including those executed as 2222** part of trigger programs. ^Executing any other type of SQL statement 2223** does not affect the value returned by sqlite3_total_changes(). 2224** 2225** ^Changes made as part of [foreign key actions] are included in the 2226** count, but those made as part of REPLACE constraint resolution are 2227** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2228** are not counted. 2229** 2230** See also the [sqlite3_changes()] interface, the 2231** [count_changes pragma], and the [total_changes() SQL function]. 2232** 2233** If a separate thread makes changes on the same database connection 2234** while [sqlite3_total_changes()] is running then the value 2235** returned is unpredictable and not meaningful. 2236*/ 2237int sqlite3_total_changes(sqlite3*); 2238 2239/* 2240** CAPI3REF: Interrupt A Long-Running Query 2241** METHOD: sqlite3 2242** 2243** ^This function causes any pending database operation to abort and 2244** return at its earliest opportunity. This routine is typically 2245** called in response to a user action such as pressing "Cancel" 2246** or Ctrl-C where the user wants a long query operation to halt 2247** immediately. 2248** 2249** ^It is safe to call this routine from a thread different from the 2250** thread that is currently running the database operation. But it 2251** is not safe to call this routine with a [database connection] that 2252** is closed or might close before sqlite3_interrupt() returns. 2253** 2254** ^If an SQL operation is very nearly finished at the time when 2255** sqlite3_interrupt() is called, then it might not have an opportunity 2256** to be interrupted and might continue to completion. 2257** 2258** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2259** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2260** that is inside an explicit transaction, then the entire transaction 2261** will be rolled back automatically. 2262** 2263** ^The sqlite3_interrupt(D) call is in effect until all currently running 2264** SQL statements on [database connection] D complete. ^Any new SQL statements 2265** that are started after the sqlite3_interrupt() call and before the 2266** running statements reaches zero are interrupted as if they had been 2267** running prior to the sqlite3_interrupt() call. ^New SQL statements 2268** that are started after the running statement count reaches zero are 2269** not effected by the sqlite3_interrupt(). 2270** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2271** SQL statements is a no-op and has no effect on SQL statements 2272** that are started after the sqlite3_interrupt() call returns. 2273*/ 2274void sqlite3_interrupt(sqlite3*); 2275 2276/* 2277** CAPI3REF: Determine If An SQL Statement Is Complete 2278** 2279** These routines are useful during command-line input to determine if the 2280** currently entered text seems to form a complete SQL statement or 2281** if additional input is needed before sending the text into 2282** SQLite for parsing. ^These routines return 1 if the input string 2283** appears to be a complete SQL statement. ^A statement is judged to be 2284** complete if it ends with a semicolon token and is not a prefix of a 2285** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2286** string literals or quoted identifier names or comments are not 2287** independent tokens (they are part of the token in which they are 2288** embedded) and thus do not count as a statement terminator. ^Whitespace 2289** and comments that follow the final semicolon are ignored. 2290** 2291** ^These routines return 0 if the statement is incomplete. ^If a 2292** memory allocation fails, then SQLITE_NOMEM is returned. 2293** 2294** ^These routines do not parse the SQL statements thus 2295** will not detect syntactically incorrect SQL. 2296** 2297** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2298** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2299** automatically by sqlite3_complete16(). If that initialization fails, 2300** then the return value from sqlite3_complete16() will be non-zero 2301** regardless of whether or not the input SQL is complete.)^ 2302** 2303** The input to [sqlite3_complete()] must be a zero-terminated 2304** UTF-8 string. 2305** 2306** The input to [sqlite3_complete16()] must be a zero-terminated 2307** UTF-16 string in native byte order. 2308*/ 2309int sqlite3_complete(const char *sql); 2310int sqlite3_complete16(const void *sql); 2311 2312/* 2313** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2314** KEYWORDS: {busy-handler callback} {busy handler} 2315** METHOD: sqlite3 2316** 2317** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2318** that might be invoked with argument P whenever 2319** an attempt is made to access a database table associated with 2320** [database connection] D when another thread 2321** or process has the table locked. 2322** The sqlite3_busy_handler() interface is used to implement 2323** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2324** 2325** ^If the busy callback is NULL, then [SQLITE_BUSY] 2326** is returned immediately upon encountering the lock. ^If the busy callback 2327** is not NULL, then the callback might be invoked with two arguments. 2328** 2329** ^The first argument to the busy handler is a copy of the void* pointer which 2330** is the third argument to sqlite3_busy_handler(). ^The second argument to 2331** the busy handler callback is the number of times that the busy handler has 2332** been invoked previously for the same locking event. ^If the 2333** busy callback returns 0, then no additional attempts are made to 2334** access the database and [SQLITE_BUSY] is returned 2335** to the application. 2336** ^If the callback returns non-zero, then another attempt 2337** is made to access the database and the cycle repeats. 2338** 2339** The presence of a busy handler does not guarantee that it will be invoked 2340** when there is lock contention. ^If SQLite determines that invoking the busy 2341** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2342** to the application instead of invoking the 2343** busy handler. 2344** Consider a scenario where one process is holding a read lock that 2345** it is trying to promote to a reserved lock and 2346** a second process is holding a reserved lock that it is trying 2347** to promote to an exclusive lock. The first process cannot proceed 2348** because it is blocked by the second and the second process cannot 2349** proceed because it is blocked by the first. If both processes 2350** invoke the busy handlers, neither will make any progress. Therefore, 2351** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2352** will induce the first process to release its read lock and allow 2353** the second process to proceed. 2354** 2355** ^The default busy callback is NULL. 2356** 2357** ^(There can only be a single busy handler defined for each 2358** [database connection]. Setting a new busy handler clears any 2359** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2360** or evaluating [PRAGMA busy_timeout=N] will change the 2361** busy handler and thus clear any previously set busy handler. 2362** 2363** The busy callback should not take any actions which modify the 2364** database connection that invoked the busy handler. In other words, 2365** the busy handler is not reentrant. Any such actions 2366** result in undefined behavior. 2367** 2368** A busy handler must not close the database connection 2369** or [prepared statement] that invoked the busy handler. 2370*/ 2371int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2372 2373/* 2374** CAPI3REF: Set A Busy Timeout 2375** METHOD: sqlite3 2376** 2377** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2378** for a specified amount of time when a table is locked. ^The handler 2379** will sleep multiple times until at least "ms" milliseconds of sleeping 2380** have accumulated. ^After at least "ms" milliseconds of sleeping, 2381** the handler returns 0 which causes [sqlite3_step()] to return 2382** [SQLITE_BUSY]. 2383** 2384** ^Calling this routine with an argument less than or equal to zero 2385** turns off all busy handlers. 2386** 2387** ^(There can only be a single busy handler for a particular 2388** [database connection] at any given moment. If another busy handler 2389** was defined (using [sqlite3_busy_handler()]) prior to calling 2390** this routine, that other busy handler is cleared.)^ 2391** 2392** See also: [PRAGMA busy_timeout] 2393*/ 2394int sqlite3_busy_timeout(sqlite3*, int ms); 2395 2396/* 2397** CAPI3REF: Convenience Routines For Running Queries 2398** METHOD: sqlite3 2399** 2400** This is a legacy interface that is preserved for backwards compatibility. 2401** Use of this interface is not recommended. 2402** 2403** Definition: A <b>result table</b> is memory data structure created by the 2404** [sqlite3_get_table()] interface. A result table records the 2405** complete query results from one or more queries. 2406** 2407** The table conceptually has a number of rows and columns. But 2408** these numbers are not part of the result table itself. These 2409** numbers are obtained separately. Let N be the number of rows 2410** and M be the number of columns. 2411** 2412** A result table is an array of pointers to zero-terminated UTF-8 strings. 2413** There are (N+1)*M elements in the array. The first M pointers point 2414** to zero-terminated strings that contain the names of the columns. 2415** The remaining entries all point to query results. NULL values result 2416** in NULL pointers. All other values are in their UTF-8 zero-terminated 2417** string representation as returned by [sqlite3_column_text()]. 2418** 2419** A result table might consist of one or more memory allocations. 2420** It is not safe to pass a result table directly to [sqlite3_free()]. 2421** A result table should be deallocated using [sqlite3_free_table()]. 2422** 2423** ^(As an example of the result table format, suppose a query result 2424** is as follows: 2425** 2426** <blockquote><pre> 2427** Name | Age 2428** ----------------------- 2429** Alice | 43 2430** Bob | 28 2431** Cindy | 21 2432** </pre></blockquote> 2433** 2434** There are two column (M==2) and three rows (N==3). Thus the 2435** result table has 8 entries. Suppose the result table is stored 2436** in an array names azResult. Then azResult holds this content: 2437** 2438** <blockquote><pre> 2439** azResult[0] = "Name"; 2440** azResult[1] = "Age"; 2441** azResult[2] = "Alice"; 2442** azResult[3] = "43"; 2443** azResult[4] = "Bob"; 2444** azResult[5] = "28"; 2445** azResult[6] = "Cindy"; 2446** azResult[7] = "21"; 2447** </pre></blockquote>)^ 2448** 2449** ^The sqlite3_get_table() function evaluates one or more 2450** semicolon-separated SQL statements in the zero-terminated UTF-8 2451** string of its 2nd parameter and returns a result table to the 2452** pointer given in its 3rd parameter. 2453** 2454** After the application has finished with the result from sqlite3_get_table(), 2455** it must pass the result table pointer to sqlite3_free_table() in order to 2456** release the memory that was malloced. Because of the way the 2457** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2458** function must not try to call [sqlite3_free()] directly. Only 2459** [sqlite3_free_table()] is able to release the memory properly and safely. 2460** 2461** The sqlite3_get_table() interface is implemented as a wrapper around 2462** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2463** to any internal data structures of SQLite. It uses only the public 2464** interface defined here. As a consequence, errors that occur in the 2465** wrapper layer outside of the internal [sqlite3_exec()] call are not 2466** reflected in subsequent calls to [sqlite3_errcode()] or 2467** [sqlite3_errmsg()]. 2468*/ 2469int sqlite3_get_table( 2470 sqlite3 *db, /* An open database */ 2471 const char *zSql, /* SQL to be evaluated */ 2472 char ***pazResult, /* Results of the query */ 2473 int *pnRow, /* Number of result rows written here */ 2474 int *pnColumn, /* Number of result columns written here */ 2475 char **pzErrmsg /* Error msg written here */ 2476); 2477void sqlite3_free_table(char **result); 2478 2479/* 2480** CAPI3REF: Formatted String Printing Functions 2481** 2482** These routines are work-alikes of the "printf()" family of functions 2483** from the standard C library. 2484** These routines understand most of the common K&R formatting options, 2485** plus some additional non-standard formats, detailed below. 2486** Note that some of the more obscure formatting options from recent 2487** C-library standards are omitted from this implementation. 2488** 2489** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2490** results into memory obtained from [sqlite3_malloc()]. 2491** The strings returned by these two routines should be 2492** released by [sqlite3_free()]. ^Both routines return a 2493** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2494** memory to hold the resulting string. 2495** 2496** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2497** the standard C library. The result is written into the 2498** buffer supplied as the second parameter whose size is given by 2499** the first parameter. Note that the order of the 2500** first two parameters is reversed from snprintf().)^ This is an 2501** historical accident that cannot be fixed without breaking 2502** backwards compatibility. ^(Note also that sqlite3_snprintf() 2503** returns a pointer to its buffer instead of the number of 2504** characters actually written into the buffer.)^ We admit that 2505** the number of characters written would be a more useful return 2506** value but we cannot change the implementation of sqlite3_snprintf() 2507** now without breaking compatibility. 2508** 2509** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2510** guarantees that the buffer is always zero-terminated. ^The first 2511** parameter "n" is the total size of the buffer, including space for 2512** the zero terminator. So the longest string that can be completely 2513** written will be n-1 characters. 2514** 2515** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2516** 2517** These routines all implement some additional formatting 2518** options that are useful for constructing SQL statements. 2519** All of the usual printf() formatting options apply. In addition, there 2520** is are "%q", "%Q", "%w" and "%z" options. 2521** 2522** ^(The %q option works like %s in that it substitutes a nul-terminated 2523** string from the argument list. But %q also doubles every '\'' character. 2524** %q is designed for use inside a string literal.)^ By doubling each '\'' 2525** character it escapes that character and allows it to be inserted into 2526** the string. 2527** 2528** For example, assume the string variable zText contains text as follows: 2529** 2530** <blockquote><pre> 2531** char *zText = "It's a happy day!"; 2532** </pre></blockquote> 2533** 2534** One can use this text in an SQL statement as follows: 2535** 2536** <blockquote><pre> 2537** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2538** sqlite3_exec(db, zSQL, 0, 0, 0); 2539** sqlite3_free(zSQL); 2540** </pre></blockquote> 2541** 2542** Because the %q format string is used, the '\'' character in zText 2543** is escaped and the SQL generated is as follows: 2544** 2545** <blockquote><pre> 2546** INSERT INTO table1 VALUES('It''s a happy day!') 2547** </pre></blockquote> 2548** 2549** This is correct. Had we used %s instead of %q, the generated SQL 2550** would have looked like this: 2551** 2552** <blockquote><pre> 2553** INSERT INTO table1 VALUES('It's a happy day!'); 2554** </pre></blockquote> 2555** 2556** This second example is an SQL syntax error. As a general rule you should 2557** always use %q instead of %s when inserting text into a string literal. 2558** 2559** ^(The %Q option works like %q except it also adds single quotes around 2560** the outside of the total string. Additionally, if the parameter in the 2561** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2562** single quotes).)^ So, for example, one could say: 2563** 2564** <blockquote><pre> 2565** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2566** sqlite3_exec(db, zSQL, 0, 0, 0); 2567** sqlite3_free(zSQL); 2568** </pre></blockquote> 2569** 2570** The code above will render a correct SQL statement in the zSQL 2571** variable even if the zText variable is a NULL pointer. 2572** 2573** ^(The "%w" formatting option is like "%q" except that it expects to 2574** be contained within double-quotes instead of single quotes, and it 2575** escapes the double-quote character instead of the single-quote 2576** character.)^ The "%w" formatting option is intended for safely inserting 2577** table and column names into a constructed SQL statement. 2578** 2579** ^(The "%z" formatting option works like "%s" but with the 2580** addition that after the string has been read and copied into 2581** the result, [sqlite3_free()] is called on the input string.)^ 2582*/ 2583char *sqlite3_mprintf(const char*,...); 2584char *sqlite3_vmprintf(const char*, va_list); 2585char *sqlite3_snprintf(int,char*,const char*, ...); 2586char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2587 2588/* 2589** CAPI3REF: Memory Allocation Subsystem 2590** 2591** The SQLite core uses these three routines for all of its own 2592** internal memory allocation needs. "Core" in the previous sentence 2593** does not include operating-system specific VFS implementation. The 2594** Windows VFS uses native malloc() and free() for some operations. 2595** 2596** ^The sqlite3_malloc() routine returns a pointer to a block 2597** of memory at least N bytes in length, where N is the parameter. 2598** ^If sqlite3_malloc() is unable to obtain sufficient free 2599** memory, it returns a NULL pointer. ^If the parameter N to 2600** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2601** a NULL pointer. 2602** 2603** ^The sqlite3_malloc64(N) routine works just like 2604** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2605** of a signed 32-bit integer. 2606** 2607** ^Calling sqlite3_free() with a pointer previously returned 2608** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2609** that it might be reused. ^The sqlite3_free() routine is 2610** a no-op if is called with a NULL pointer. Passing a NULL pointer 2611** to sqlite3_free() is harmless. After being freed, memory 2612** should neither be read nor written. Even reading previously freed 2613** memory might result in a segmentation fault or other severe error. 2614** Memory corruption, a segmentation fault, or other severe error 2615** might result if sqlite3_free() is called with a non-NULL pointer that 2616** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2617** 2618** ^The sqlite3_realloc(X,N) interface attempts to resize a 2619** prior memory allocation X to be at least N bytes. 2620** ^If the X parameter to sqlite3_realloc(X,N) 2621** is a NULL pointer then its behavior is identical to calling 2622** sqlite3_malloc(N). 2623** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2624** negative then the behavior is exactly the same as calling 2625** sqlite3_free(X). 2626** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2627** of at least N bytes in size or NULL if insufficient memory is available. 2628** ^If M is the size of the prior allocation, then min(N,M) bytes 2629** of the prior allocation are copied into the beginning of buffer returned 2630** by sqlite3_realloc(X,N) and the prior allocation is freed. 2631** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2632** prior allocation is not freed. 2633** 2634** ^The sqlite3_realloc64(X,N) interfaces works the same as 2635** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2636** of a 32-bit signed integer. 2637** 2638** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2639** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2640** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2641** ^The value returned by sqlite3_msize(X) might be larger than the number 2642** of bytes requested when X was allocated. ^If X is a NULL pointer then 2643** sqlite3_msize(X) returns zero. If X points to something that is not 2644** the beginning of memory allocation, or if it points to a formerly 2645** valid memory allocation that has now been freed, then the behavior 2646** of sqlite3_msize(X) is undefined and possibly harmful. 2647** 2648** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2649** sqlite3_malloc64(), and sqlite3_realloc64() 2650** is always aligned to at least an 8 byte boundary, or to a 2651** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2652** option is used. 2653** 2654** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2655** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2656** implementation of these routines to be omitted. That capability 2657** is no longer provided. Only built-in memory allocators can be used. 2658** 2659** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2660** the system malloc() and free() directly when converting 2661** filenames between the UTF-8 encoding used by SQLite 2662** and whatever filename encoding is used by the particular Windows 2663** installation. Memory allocation errors were detected, but 2664** they were reported back as [SQLITE_CANTOPEN] or 2665** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2666** 2667** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2668** must be either NULL or else pointers obtained from a prior 2669** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2670** not yet been released. 2671** 2672** The application must not read or write any part of 2673** a block of memory after it has been released using 2674** [sqlite3_free()] or [sqlite3_realloc()]. 2675*/ 2676void *sqlite3_malloc(int); 2677void *sqlite3_malloc64(sqlite3_uint64); 2678void *sqlite3_realloc(void*, int); 2679void *sqlite3_realloc64(void*, sqlite3_uint64); 2680void sqlite3_free(void*); 2681sqlite3_uint64 sqlite3_msize(void*); 2682 2683/* 2684** CAPI3REF: Memory Allocator Statistics 2685** 2686** SQLite provides these two interfaces for reporting on the status 2687** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2688** routines, which form the built-in memory allocation subsystem. 2689** 2690** ^The [sqlite3_memory_used()] routine returns the number of bytes 2691** of memory currently outstanding (malloced but not freed). 2692** ^The [sqlite3_memory_highwater()] routine returns the maximum 2693** value of [sqlite3_memory_used()] since the high-water mark 2694** was last reset. ^The values returned by [sqlite3_memory_used()] and 2695** [sqlite3_memory_highwater()] include any overhead 2696** added by SQLite in its implementation of [sqlite3_malloc()], 2697** but not overhead added by the any underlying system library 2698** routines that [sqlite3_malloc()] may call. 2699** 2700** ^The memory high-water mark is reset to the current value of 2701** [sqlite3_memory_used()] if and only if the parameter to 2702** [sqlite3_memory_highwater()] is true. ^The value returned 2703** by [sqlite3_memory_highwater(1)] is the high-water mark 2704** prior to the reset. 2705*/ 2706sqlite3_int64 sqlite3_memory_used(void); 2707sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2708 2709/* 2710** CAPI3REF: Pseudo-Random Number Generator 2711** 2712** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2713** select random [ROWID | ROWIDs] when inserting new records into a table that 2714** already uses the largest possible [ROWID]. The PRNG is also used for 2715** the build-in random() and randomblob() SQL functions. This interface allows 2716** applications to access the same PRNG for other purposes. 2717** 2718** ^A call to this routine stores N bytes of randomness into buffer P. 2719** ^The P parameter can be a NULL pointer. 2720** 2721** ^If this routine has not been previously called or if the previous 2722** call had N less than one or a NULL pointer for P, then the PRNG is 2723** seeded using randomness obtained from the xRandomness method of 2724** the default [sqlite3_vfs] object. 2725** ^If the previous call to this routine had an N of 1 or more and a 2726** non-NULL P then the pseudo-randomness is generated 2727** internally and without recourse to the [sqlite3_vfs] xRandomness 2728** method. 2729*/ 2730void sqlite3_randomness(int N, void *P); 2731 2732/* 2733** CAPI3REF: Compile-Time Authorization Callbacks 2734** METHOD: sqlite3 2735** KEYWORDS: {authorizer callback} 2736** 2737** ^This routine registers an authorizer callback with a particular 2738** [database connection], supplied in the first argument. 2739** ^The authorizer callback is invoked as SQL statements are being compiled 2740** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2741** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2742** and [sqlite3_prepare16_v3()]. ^At various 2743** points during the compilation process, as logic is being created 2744** to perform various actions, the authorizer callback is invoked to 2745** see if those actions are allowed. ^The authorizer callback should 2746** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2747** specific action but allow the SQL statement to continue to be 2748** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2749** rejected with an error. ^If the authorizer callback returns 2750** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2751** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2752** the authorizer will fail with an error message. 2753** 2754** When the callback returns [SQLITE_OK], that means the operation 2755** requested is ok. ^When the callback returns [SQLITE_DENY], the 2756** [sqlite3_prepare_v2()] or equivalent call that triggered the 2757** authorizer will fail with an error message explaining that 2758** access is denied. 2759** 2760** ^The first parameter to the authorizer callback is a copy of the third 2761** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2762** to the callback is an integer [SQLITE_COPY | action code] that specifies 2763** the particular action to be authorized. ^The third through sixth parameters 2764** to the callback are either NULL pointers or zero-terminated strings 2765** that contain additional details about the action to be authorized. 2766** Applications must always be prepared to encounter a NULL pointer in any 2767** of the third through the sixth parameters of the authorization callback. 2768** 2769** ^If the action code is [SQLITE_READ] 2770** and the callback returns [SQLITE_IGNORE] then the 2771** [prepared statement] statement is constructed to substitute 2772** a NULL value in place of the table column that would have 2773** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2774** return can be used to deny an untrusted user access to individual 2775** columns of a table. 2776** ^When a table is referenced by a [SELECT] but no column values are 2777** extracted from that table (for example in a query like 2778** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2779** is invoked once for that table with a column name that is an empty string. 2780** ^If the action code is [SQLITE_DELETE] and the callback returns 2781** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2782** [truncate optimization] is disabled and all rows are deleted individually. 2783** 2784** An authorizer is used when [sqlite3_prepare | preparing] 2785** SQL statements from an untrusted source, to ensure that the SQL statements 2786** do not try to access data they are not allowed to see, or that they do not 2787** try to execute malicious statements that damage the database. For 2788** example, an application may allow a user to enter arbitrary 2789** SQL queries for evaluation by a database. But the application does 2790** not want the user to be able to make arbitrary changes to the 2791** database. An authorizer could then be put in place while the 2792** user-entered SQL is being [sqlite3_prepare | prepared] that 2793** disallows everything except [SELECT] statements. 2794** 2795** Applications that need to process SQL from untrusted sources 2796** might also consider lowering resource limits using [sqlite3_limit()] 2797** and limiting database size using the [max_page_count] [PRAGMA] 2798** in addition to using an authorizer. 2799** 2800** ^(Only a single authorizer can be in place on a database connection 2801** at a time. Each call to sqlite3_set_authorizer overrides the 2802** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2803** The authorizer is disabled by default. 2804** 2805** The authorizer callback must not do anything that will modify 2806** the database connection that invoked the authorizer callback. 2807** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2808** database connections for the meaning of "modify" in this paragraph. 2809** 2810** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2811** statement might be re-prepared during [sqlite3_step()] due to a 2812** schema change. Hence, the application should ensure that the 2813** correct authorizer callback remains in place during the [sqlite3_step()]. 2814** 2815** ^Note that the authorizer callback is invoked only during 2816** [sqlite3_prepare()] or its variants. Authorization is not 2817** performed during statement evaluation in [sqlite3_step()], unless 2818** as stated in the previous paragraph, sqlite3_step() invokes 2819** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2820*/ 2821int sqlite3_set_authorizer( 2822 sqlite3*, 2823 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2824 void *pUserData 2825); 2826 2827/* 2828** CAPI3REF: Authorizer Return Codes 2829** 2830** The [sqlite3_set_authorizer | authorizer callback function] must 2831** return either [SQLITE_OK] or one of these two constants in order 2832** to signal SQLite whether or not the action is permitted. See the 2833** [sqlite3_set_authorizer | authorizer documentation] for additional 2834** information. 2835** 2836** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2837** returned from the [sqlite3_vtab_on_conflict()] interface. 2838*/ 2839#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2840#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2841 2842/* 2843** CAPI3REF: Authorizer Action Codes 2844** 2845** The [sqlite3_set_authorizer()] interface registers a callback function 2846** that is invoked to authorize certain SQL statement actions. The 2847** second parameter to the callback is an integer code that specifies 2848** what action is being authorized. These are the integer action codes that 2849** the authorizer callback may be passed. 2850** 2851** These action code values signify what kind of operation is to be 2852** authorized. The 3rd and 4th parameters to the authorization 2853** callback function will be parameters or NULL depending on which of these 2854** codes is used as the second parameter. ^(The 5th parameter to the 2855** authorizer callback is the name of the database ("main", "temp", 2856** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2857** is the name of the inner-most trigger or view that is responsible for 2858** the access attempt or NULL if this access attempt is directly from 2859** top-level SQL code. 2860*/ 2861/******************************************* 3rd ************ 4th ***********/ 2862#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2863#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2864#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2865#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2866#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2867#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2868#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2869#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2870#define SQLITE_DELETE 9 /* Table Name NULL */ 2871#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2872#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2873#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2874#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2875#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2876#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2877#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2878#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2879#define SQLITE_INSERT 18 /* Table Name NULL */ 2880#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2881#define SQLITE_READ 20 /* Table Name Column Name */ 2882#define SQLITE_SELECT 21 /* NULL NULL */ 2883#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2884#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2885#define SQLITE_ATTACH 24 /* Filename NULL */ 2886#define SQLITE_DETACH 25 /* Database Name NULL */ 2887#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2888#define SQLITE_REINDEX 27 /* Index Name NULL */ 2889#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2890#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2891#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2892#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2893#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2894#define SQLITE_COPY 0 /* No longer used */ 2895#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2896 2897/* 2898** CAPI3REF: Tracing And Profiling Functions 2899** METHOD: sqlite3 2900** 2901** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 2902** instead of the routines described here. 2903** 2904** These routines register callback functions that can be used for 2905** tracing and profiling the execution of SQL statements. 2906** 2907** ^The callback function registered by sqlite3_trace() is invoked at 2908** various times when an SQL statement is being run by [sqlite3_step()]. 2909** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2910** SQL statement text as the statement first begins executing. 2911** ^(Additional sqlite3_trace() callbacks might occur 2912** as each triggered subprogram is entered. The callbacks for triggers 2913** contain a UTF-8 SQL comment that identifies the trigger.)^ 2914** 2915** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2916** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2917** 2918** ^The callback function registered by sqlite3_profile() is invoked 2919** as each SQL statement finishes. ^The profile callback contains 2920** the original statement text and an estimate of wall-clock time 2921** of how long that statement took to run. ^The profile callback 2922** time is in units of nanoseconds, however the current implementation 2923** is only capable of millisecond resolution so the six least significant 2924** digits in the time are meaningless. Future versions of SQLite 2925** might provide greater resolution on the profiler callback. The 2926** sqlite3_profile() function is considered experimental and is 2927** subject to change in future versions of SQLite. 2928*/ 2929SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 2930 void(*xTrace)(void*,const char*), void*); 2931SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 2932 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2933 2934/* 2935** CAPI3REF: SQL Trace Event Codes 2936** KEYWORDS: SQLITE_TRACE 2937** 2938** These constants identify classes of events that can be monitored 2939** using the [sqlite3_trace_v2()] tracing logic. The third argument 2940** to [sqlite3_trace_v2()] is an OR-ed combination of one or more of 2941** the following constants. ^The first argument to the trace callback 2942** is one of the following constants. 2943** 2944** New tracing constants may be added in future releases. 2945** 2946** ^A trace callback has four arguments: xCallback(T,C,P,X). 2947** ^The T argument is one of the integer type codes above. 2948** ^The C argument is a copy of the context pointer passed in as the 2949** fourth argument to [sqlite3_trace_v2()]. 2950** The P and X arguments are pointers whose meanings depend on T. 2951** 2952** <dl> 2953** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 2954** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 2955** first begins running and possibly at other times during the 2956** execution of the prepared statement, such as at the start of each 2957** trigger subprogram. ^The P argument is a pointer to the 2958** [prepared statement]. ^The X argument is a pointer to a string which 2959** is the unexpanded SQL text of the prepared statement or an SQL comment 2960** that indicates the invocation of a trigger. ^The callback can compute 2961** the same text that would have been returned by the legacy [sqlite3_trace()] 2962** interface by using the X argument when X begins with "--" and invoking 2963** [sqlite3_expanded_sql(P)] otherwise. 2964** 2965** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 2966** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 2967** information as is provided by the [sqlite3_profile()] callback. 2968** ^The P argument is a pointer to the [prepared statement] and the 2969** X argument points to a 64-bit integer which is the estimated of 2970** the number of nanosecond that the prepared statement took to run. 2971** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 2972** 2973** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 2974** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 2975** statement generates a single row of result. 2976** ^The P argument is a pointer to the [prepared statement] and the 2977** X argument is unused. 2978** 2979** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 2980** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 2981** connection closes. 2982** ^The P argument is a pointer to the [database connection] object 2983** and the X argument is unused. 2984** </dl> 2985*/ 2986#define SQLITE_TRACE_STMT 0x01 2987#define SQLITE_TRACE_PROFILE 0x02 2988#define SQLITE_TRACE_ROW 0x04 2989#define SQLITE_TRACE_CLOSE 0x08 2990 2991/* 2992** CAPI3REF: SQL Trace Hook 2993** METHOD: sqlite3 2994** 2995** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 2996** function X against [database connection] D, using property mask M 2997** and context pointer P. ^If the X callback is 2998** NULL or if the M mask is zero, then tracing is disabled. The 2999** M argument should be the bitwise OR-ed combination of 3000** zero or more [SQLITE_TRACE] constants. 3001** 3002** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 3003** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 3004** 3005** ^The X callback is invoked whenever any of the events identified by 3006** mask M occur. ^The integer return value from the callback is currently 3007** ignored, though this may change in future releases. Callback 3008** implementations should return zero to ensure future compatibility. 3009** 3010** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 3011** ^The T argument is one of the [SQLITE_TRACE] 3012** constants to indicate why the callback was invoked. 3013** ^The C argument is a copy of the context pointer. 3014** The P and X arguments are pointers whose meanings depend on T. 3015** 3016** The sqlite3_trace_v2() interface is intended to replace the legacy 3017** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 3018** are deprecated. 3019*/ 3020int sqlite3_trace_v2( 3021 sqlite3*, 3022 unsigned uMask, 3023 int(*xCallback)(unsigned,void*,void*,void*), 3024 void *pCtx 3025); 3026 3027/* 3028** CAPI3REF: Query Progress Callbacks 3029** METHOD: sqlite3 3030** 3031** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 3032** function X to be invoked periodically during long running calls to 3033** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 3034** database connection D. An example use for this 3035** interface is to keep a GUI updated during a large query. 3036** 3037** ^The parameter P is passed through as the only parameter to the 3038** callback function X. ^The parameter N is the approximate number of 3039** [virtual machine instructions] that are evaluated between successive 3040** invocations of the callback X. ^If N is less than one then the progress 3041** handler is disabled. 3042** 3043** ^Only a single progress handler may be defined at one time per 3044** [database connection]; setting a new progress handler cancels the 3045** old one. ^Setting parameter X to NULL disables the progress handler. 3046** ^The progress handler is also disabled by setting N to a value less 3047** than 1. 3048** 3049** ^If the progress callback returns non-zero, the operation is 3050** interrupted. This feature can be used to implement a 3051** "Cancel" button on a GUI progress dialog box. 3052** 3053** The progress handler callback must not do anything that will modify 3054** the database connection that invoked the progress handler. 3055** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3056** database connections for the meaning of "modify" in this paragraph. 3057** 3058*/ 3059void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3060 3061/* 3062** CAPI3REF: Opening A New Database Connection 3063** CONSTRUCTOR: sqlite3 3064** 3065** ^These routines open an SQLite database file as specified by the 3066** filename argument. ^The filename argument is interpreted as UTF-8 for 3067** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3068** order for sqlite3_open16(). ^(A [database connection] handle is usually 3069** returned in *ppDb, even if an error occurs. The only exception is that 3070** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3071** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3072** object.)^ ^(If the database is opened (and/or created) successfully, then 3073** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3074** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3075** an English language description of the error following a failure of any 3076** of the sqlite3_open() routines. 3077** 3078** ^The default encoding will be UTF-8 for databases created using 3079** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3080** created using sqlite3_open16() will be UTF-16 in the native byte order. 3081** 3082** Whether or not an error occurs when it is opened, resources 3083** associated with the [database connection] handle should be released by 3084** passing it to [sqlite3_close()] when it is no longer required. 3085** 3086** The sqlite3_open_v2() interface works like sqlite3_open() 3087** except that it accepts two additional parameters for additional control 3088** over the new database connection. ^(The flags parameter to 3089** sqlite3_open_v2() can take one of 3090** the following three values, optionally combined with the 3091** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 3092** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 3093** 3094** <dl> 3095** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3096** <dd>The database is opened in read-only mode. If the database does not 3097** already exist, an error is returned.</dd>)^ 3098** 3099** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3100** <dd>The database is opened for reading and writing if possible, or reading 3101** only if the file is write protected by the operating system. In either 3102** case the database must already exist, otherwise an error is returned.</dd>)^ 3103** 3104** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3105** <dd>The database is opened for reading and writing, and is created if 3106** it does not already exist. This is the behavior that is always used for 3107** sqlite3_open() and sqlite3_open16().</dd>)^ 3108** </dl> 3109** 3110** If the 3rd parameter to sqlite3_open_v2() is not one of the 3111** combinations shown above optionally combined with other 3112** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3113** then the behavior is undefined. 3114** 3115** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 3116** opens in the multi-thread [threading mode] as long as the single-thread 3117** mode has not been set at compile-time or start-time. ^If the 3118** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 3119** in the serialized [threading mode] unless single-thread was 3120** previously selected at compile-time or start-time. 3121** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 3122** eligible to use [shared cache mode], regardless of whether or not shared 3123** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 3124** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 3125** participate in [shared cache mode] even if it is enabled. 3126** 3127** ^The fourth parameter to sqlite3_open_v2() is the name of the 3128** [sqlite3_vfs] object that defines the operating system interface that 3129** the new database connection should use. ^If the fourth parameter is 3130** a NULL pointer then the default [sqlite3_vfs] object is used. 3131** 3132** ^If the filename is ":memory:", then a private, temporary in-memory database 3133** is created for the connection. ^This in-memory database will vanish when 3134** the database connection is closed. Future versions of SQLite might 3135** make use of additional special filenames that begin with the ":" character. 3136** It is recommended that when a database filename actually does begin with 3137** a ":" character you should prefix the filename with a pathname such as 3138** "./" to avoid ambiguity. 3139** 3140** ^If the filename is an empty string, then a private, temporary 3141** on-disk database will be created. ^This private database will be 3142** automatically deleted as soon as the database connection is closed. 3143** 3144** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3145** 3146** ^If [URI filename] interpretation is enabled, and the filename argument 3147** begins with "file:", then the filename is interpreted as a URI. ^URI 3148** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3149** set in the fourth argument to sqlite3_open_v2(), or if it has 3150** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3151** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3152** As of SQLite version 3.7.7, URI filename interpretation is turned off 3153** by default, but future releases of SQLite might enable URI filename 3154** interpretation by default. See "[URI filenames]" for additional 3155** information. 3156** 3157** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3158** authority, then it must be either an empty string or the string 3159** "localhost". ^If the authority is not an empty string or "localhost", an 3160** error is returned to the caller. ^The fragment component of a URI, if 3161** present, is ignored. 3162** 3163** ^SQLite uses the path component of the URI as the name of the disk file 3164** which contains the database. ^If the path begins with a '/' character, 3165** then it is interpreted as an absolute path. ^If the path does not begin 3166** with a '/' (meaning that the authority section is omitted from the URI) 3167** then the path is interpreted as a relative path. 3168** ^(On windows, the first component of an absolute path 3169** is a drive specification (e.g. "C:").)^ 3170** 3171** [[core URI query parameters]] 3172** The query component of a URI may contain parameters that are interpreted 3173** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3174** SQLite and its built-in [VFSes] interpret the 3175** following query parameters: 3176** 3177** <ul> 3178** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3179** a VFS object that provides the operating system interface that should 3180** be used to access the database file on disk. ^If this option is set to 3181** an empty string the default VFS object is used. ^Specifying an unknown 3182** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3183** present, then the VFS specified by the option takes precedence over 3184** the value passed as the fourth parameter to sqlite3_open_v2(). 3185** 3186** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3187** "rwc", or "memory". Attempting to set it to any other value is 3188** an error)^. 3189** ^If "ro" is specified, then the database is opened for read-only 3190** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3191** third argument to sqlite3_open_v2(). ^If the mode option is set to 3192** "rw", then the database is opened for read-write (but not create) 3193** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3194** been set. ^Value "rwc" is equivalent to setting both 3195** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3196** set to "memory" then a pure [in-memory database] that never reads 3197** or writes from disk is used. ^It is an error to specify a value for 3198** the mode parameter that is less restrictive than that specified by 3199** the flags passed in the third parameter to sqlite3_open_v2(). 3200** 3201** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3202** "private". ^Setting it to "shared" is equivalent to setting the 3203** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3204** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3205** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3206** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3207** a URI filename, its value overrides any behavior requested by setting 3208** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3209** 3210** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3211** [powersafe overwrite] property does or does not apply to the 3212** storage media on which the database file resides. 3213** 3214** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3215** which if set disables file locking in rollback journal modes. This 3216** is useful for accessing a database on a filesystem that does not 3217** support locking. Caution: Database corruption might result if two 3218** or more processes write to the same database and any one of those 3219** processes uses nolock=1. 3220** 3221** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3222** parameter that indicates that the database file is stored on 3223** read-only media. ^When immutable is set, SQLite assumes that the 3224** database file cannot be changed, even by a process with higher 3225** privilege, and so the database is opened read-only and all locking 3226** and change detection is disabled. Caution: Setting the immutable 3227** property on a database file that does in fact change can result 3228** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3229** See also: [SQLITE_IOCAP_IMMUTABLE]. 3230** 3231** </ul> 3232** 3233** ^Specifying an unknown parameter in the query component of a URI is not an 3234** error. Future versions of SQLite might understand additional query 3235** parameters. See "[query parameters with special meaning to SQLite]" for 3236** additional information. 3237** 3238** [[URI filename examples]] <h3>URI filename examples</h3> 3239** 3240** <table border="1" align=center cellpadding=5> 3241** <tr><th> URI filenames <th> Results 3242** <tr><td> file:data.db <td> 3243** Open the file "data.db" in the current directory. 3244** <tr><td> file:/home/fred/data.db<br> 3245** file:///home/fred/data.db <br> 3246** file://localhost/home/fred/data.db <br> <td> 3247** Open the database file "/home/fred/data.db". 3248** <tr><td> file://darkstar/home/fred/data.db <td> 3249** An error. "darkstar" is not a recognized authority. 3250** <tr><td style="white-space:nowrap"> 3251** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3252** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3253** C:. Note that the %20 escaping in this example is not strictly 3254** necessary - space characters can be used literally 3255** in URI filenames. 3256** <tr><td> file:data.db?mode=ro&cache=private <td> 3257** Open file "data.db" in the current directory for read-only access. 3258** Regardless of whether or not shared-cache mode is enabled by 3259** default, use a private cache. 3260** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3261** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3262** that uses dot-files in place of posix advisory locking. 3263** <tr><td> file:data.db?mode=readonly <td> 3264** An error. "readonly" is not a valid option for the "mode" parameter. 3265** </table> 3266** 3267** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3268** query components of a URI. A hexadecimal escape sequence consists of a 3269** percent sign - "%" - followed by exactly two hexadecimal digits 3270** specifying an octet value. ^Before the path or query components of a 3271** URI filename are interpreted, they are encoded using UTF-8 and all 3272** hexadecimal escape sequences replaced by a single byte containing the 3273** corresponding octet. If this process generates an invalid UTF-8 encoding, 3274** the results are undefined. 3275** 3276** <b>Note to Windows users:</b> The encoding used for the filename argument 3277** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3278** codepage is currently defined. Filenames containing international 3279** characters must be converted to UTF-8 prior to passing them into 3280** sqlite3_open() or sqlite3_open_v2(). 3281** 3282** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3283** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3284** features that require the use of temporary files may fail. 3285** 3286** See also: [sqlite3_temp_directory] 3287*/ 3288int sqlite3_open( 3289 const char *filename, /* Database filename (UTF-8) */ 3290 sqlite3 **ppDb /* OUT: SQLite db handle */ 3291); 3292int sqlite3_open16( 3293 const void *filename, /* Database filename (UTF-16) */ 3294 sqlite3 **ppDb /* OUT: SQLite db handle */ 3295); 3296int sqlite3_open_v2( 3297 const char *filename, /* Database filename (UTF-8) */ 3298 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3299 int flags, /* Flags */ 3300 const char *zVfs /* Name of VFS module to use */ 3301); 3302 3303/* 3304** CAPI3REF: Obtain Values For URI Parameters 3305** 3306** These are utility routines, useful to VFS implementations, that check 3307** to see if a database file was a URI that contained a specific query 3308** parameter, and if so obtains the value of that query parameter. 3309** 3310** If F is the database filename pointer passed into the xOpen() method of 3311** a VFS implementation when the flags parameter to xOpen() has one or 3312** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3313** P is the name of the query parameter, then 3314** sqlite3_uri_parameter(F,P) returns the value of the P 3315** parameter if it exists or a NULL pointer if P does not appear as a 3316** query parameter on F. If P is a query parameter of F 3317** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3318** a pointer to an empty string. 3319** 3320** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3321** parameter and returns true (1) or false (0) according to the value 3322** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3323** value of query parameter P is one of "yes", "true", or "on" in any 3324** case or if the value begins with a non-zero number. The 3325** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3326** query parameter P is one of "no", "false", or "off" in any case or 3327** if the value begins with a numeric zero. If P is not a query 3328** parameter on F or if the value of P is does not match any of the 3329** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3330** 3331** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3332** 64-bit signed integer and returns that integer, or D if P does not 3333** exist. If the value of P is something other than an integer, then 3334** zero is returned. 3335** 3336** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3337** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3338** is not a database file pathname pointer that SQLite passed into the xOpen 3339** VFS method, then the behavior of this routine is undefined and probably 3340** undesirable. 3341*/ 3342const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3343int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3344sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3345 3346 3347/* 3348** CAPI3REF: Error Codes And Messages 3349** METHOD: sqlite3 3350** 3351** ^If the most recent sqlite3_* API call associated with 3352** [database connection] D failed, then the sqlite3_errcode(D) interface 3353** returns the numeric [result code] or [extended result code] for that 3354** API call. 3355** If the most recent API call was successful, 3356** then the return value from sqlite3_errcode() is undefined. 3357** ^The sqlite3_extended_errcode() 3358** interface is the same except that it always returns the 3359** [extended result code] even when extended result codes are 3360** disabled. 3361** 3362** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3363** text that describes the error, as either UTF-8 or UTF-16 respectively. 3364** ^(Memory to hold the error message string is managed internally. 3365** The application does not need to worry about freeing the result. 3366** However, the error string might be overwritten or deallocated by 3367** subsequent calls to other SQLite interface functions.)^ 3368** 3369** ^The sqlite3_errstr() interface returns the English-language text 3370** that describes the [result code], as UTF-8. 3371** ^(Memory to hold the error message string is managed internally 3372** and must not be freed by the application)^. 3373** 3374** When the serialized [threading mode] is in use, it might be the 3375** case that a second error occurs on a separate thread in between 3376** the time of the first error and the call to these interfaces. 3377** When that happens, the second error will be reported since these 3378** interfaces always report the most recent result. To avoid 3379** this, each thread can obtain exclusive use of the [database connection] D 3380** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3381** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3382** all calls to the interfaces listed here are completed. 3383** 3384** If an interface fails with SQLITE_MISUSE, that means the interface 3385** was invoked incorrectly by the application. In that case, the 3386** error code and message may or may not be set. 3387*/ 3388int sqlite3_errcode(sqlite3 *db); 3389int sqlite3_extended_errcode(sqlite3 *db); 3390const char *sqlite3_errmsg(sqlite3*); 3391const void *sqlite3_errmsg16(sqlite3*); 3392const char *sqlite3_errstr(int); 3393 3394/* 3395** CAPI3REF: Prepared Statement Object 3396** KEYWORDS: {prepared statement} {prepared statements} 3397** 3398** An instance of this object represents a single SQL statement that 3399** has been compiled into binary form and is ready to be evaluated. 3400** 3401** Think of each SQL statement as a separate computer program. The 3402** original SQL text is source code. A prepared statement object 3403** is the compiled object code. All SQL must be converted into a 3404** prepared statement before it can be run. 3405** 3406** The life-cycle of a prepared statement object usually goes like this: 3407** 3408** <ol> 3409** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3410** <li> Bind values to [parameters] using the sqlite3_bind_*() 3411** interfaces. 3412** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3413** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3414** to step 2. Do this zero or more times. 3415** <li> Destroy the object using [sqlite3_finalize()]. 3416** </ol> 3417*/ 3418typedef struct sqlite3_stmt sqlite3_stmt; 3419 3420/* 3421** CAPI3REF: Run-time Limits 3422** METHOD: sqlite3 3423** 3424** ^(This interface allows the size of various constructs to be limited 3425** on a connection by connection basis. The first parameter is the 3426** [database connection] whose limit is to be set or queried. The 3427** second parameter is one of the [limit categories] that define a 3428** class of constructs to be size limited. The third parameter is the 3429** new limit for that construct.)^ 3430** 3431** ^If the new limit is a negative number, the limit is unchanged. 3432** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3433** [limits | hard upper bound] 3434** set at compile-time by a C preprocessor macro called 3435** [limits | SQLITE_MAX_<i>NAME</i>]. 3436** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3437** ^Attempts to increase a limit above its hard upper bound are 3438** silently truncated to the hard upper bound. 3439** 3440** ^Regardless of whether or not the limit was changed, the 3441** [sqlite3_limit()] interface returns the prior value of the limit. 3442** ^Hence, to find the current value of a limit without changing it, 3443** simply invoke this interface with the third parameter set to -1. 3444** 3445** Run-time limits are intended for use in applications that manage 3446** both their own internal database and also databases that are controlled 3447** by untrusted external sources. An example application might be a 3448** web browser that has its own databases for storing history and 3449** separate databases controlled by JavaScript applications downloaded 3450** off the Internet. The internal databases can be given the 3451** large, default limits. Databases managed by external sources can 3452** be given much smaller limits designed to prevent a denial of service 3453** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3454** interface to further control untrusted SQL. The size of the database 3455** created by an untrusted script can be contained using the 3456** [max_page_count] [PRAGMA]. 3457** 3458** New run-time limit categories may be added in future releases. 3459*/ 3460int sqlite3_limit(sqlite3*, int id, int newVal); 3461 3462/* 3463** CAPI3REF: Run-Time Limit Categories 3464** KEYWORDS: {limit category} {*limit categories} 3465** 3466** These constants define various performance limits 3467** that can be lowered at run-time using [sqlite3_limit()]. 3468** The synopsis of the meanings of the various limits is shown below. 3469** Additional information is available at [limits | Limits in SQLite]. 3470** 3471** <dl> 3472** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3473** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3474** 3475** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3476** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3477** 3478** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3479** <dd>The maximum number of columns in a table definition or in the 3480** result set of a [SELECT] or the maximum number of columns in an index 3481** or in an ORDER BY or GROUP BY clause.</dd>)^ 3482** 3483** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3484** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3485** 3486** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3487** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3488** 3489** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3490** <dd>The maximum number of instructions in a virtual machine program 3491** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3492** the equivalent tries to allocate space for more than this many opcodes 3493** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3494** 3495** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3496** <dd>The maximum number of arguments on a function.</dd>)^ 3497** 3498** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3499** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3500** 3501** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3502** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3503** <dd>The maximum length of the pattern argument to the [LIKE] or 3504** [GLOB] operators.</dd>)^ 3505** 3506** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3507** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3508** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3509** 3510** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3511** <dd>The maximum depth of recursion for triggers.</dd>)^ 3512** 3513** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3514** <dd>The maximum number of auxiliary worker threads that a single 3515** [prepared statement] may start.</dd>)^ 3516** </dl> 3517*/ 3518#define SQLITE_LIMIT_LENGTH 0 3519#define SQLITE_LIMIT_SQL_LENGTH 1 3520#define SQLITE_LIMIT_COLUMN 2 3521#define SQLITE_LIMIT_EXPR_DEPTH 3 3522#define SQLITE_LIMIT_COMPOUND_SELECT 4 3523#define SQLITE_LIMIT_VDBE_OP 5 3524#define SQLITE_LIMIT_FUNCTION_ARG 6 3525#define SQLITE_LIMIT_ATTACHED 7 3526#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3527#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3528#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3529#define SQLITE_LIMIT_WORKER_THREADS 11 3530 3531/* 3532** CAPI3REF: Prepare Flags 3533** 3534** These constants define various flags that can be passed into 3535** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3536** [sqlite3_prepare16_v3()] interfaces. 3537** 3538** New flags may be added in future releases of SQLite. 3539** 3540** <dl> 3541** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3542** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3543** that the prepared statement will be retained for a long time and 3544** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3545** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3546** be used just once or at most a few times and then destroyed using 3547** [sqlite3_finalize()] relatively soon. The current implementation acts 3548** on this hint by avoiding the use of [lookaside memory] so as not to 3549** deplete the limited store of lookaside memory. Future versions of 3550** SQLite may act on this hint differently. 3551** </dl> 3552*/ 3553#define SQLITE_PREPARE_PERSISTENT 0x01 3554 3555/* 3556** CAPI3REF: Compiling An SQL Statement 3557** KEYWORDS: {SQL statement compiler} 3558** METHOD: sqlite3 3559** CONSTRUCTOR: sqlite3_stmt 3560** 3561** To execute an SQL statement, it must first be compiled into a byte-code 3562** program using one of these routines. Or, in other words, these routines 3563** are constructors for the [prepared statement] object. 3564** 3565** The preferred routine to use is [sqlite3_prepare_v2()]. The 3566** [sqlite3_prepare()] interface is legacy and should be avoided. 3567** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3568** for special purposes. 3569** 3570** The use of the UTF-8 interfaces is preferred, as SQLite currently 3571** does all parsing using UTF-8. The UTF-16 interfaces are provided 3572** as a convenience. The UTF-16 interfaces work by converting the 3573** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3574** 3575** The first argument, "db", is a [database connection] obtained from a 3576** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3577** [sqlite3_open16()]. The database connection must not have been closed. 3578** 3579** The second argument, "zSql", is the statement to be compiled, encoded 3580** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 3581** and sqlite3_prepare_v3() 3582** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 3583** and sqlite3_prepare16_v3() use UTF-16. 3584** 3585** ^If the nByte argument is negative, then zSql is read up to the 3586** first zero terminator. ^If nByte is positive, then it is the 3587** number of bytes read from zSql. ^If nByte is zero, then no prepared 3588** statement is generated. 3589** If the caller knows that the supplied string is nul-terminated, then 3590** there is a small performance advantage to passing an nByte parameter that 3591** is the number of bytes in the input string <i>including</i> 3592** the nul-terminator. 3593** 3594** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3595** past the end of the first SQL statement in zSql. These routines only 3596** compile the first statement in zSql, so *pzTail is left pointing to 3597** what remains uncompiled. 3598** 3599** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3600** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3601** to NULL. ^If the input text contains no SQL (if the input is an empty 3602** string or a comment) then *ppStmt is set to NULL. 3603** The calling procedure is responsible for deleting the compiled 3604** SQL statement using [sqlite3_finalize()] after it has finished with it. 3605** ppStmt may not be NULL. 3606** 3607** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3608** otherwise an [error code] is returned. 3609** 3610** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 3611** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 3612** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 3613** are retained for backwards compatibility, but their use is discouraged. 3614** ^In the "vX" interfaces, the prepared statement 3615** that is returned (the [sqlite3_stmt] object) contains a copy of the 3616** original SQL text. This causes the [sqlite3_step()] interface to 3617** behave differently in three ways: 3618** 3619** <ol> 3620** <li> 3621** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3622** always used to do, [sqlite3_step()] will automatically recompile the SQL 3623** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3624** retries will occur before sqlite3_step() gives up and returns an error. 3625** </li> 3626** 3627** <li> 3628** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3629** [error codes] or [extended error codes]. ^The legacy behavior was that 3630** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3631** and the application would have to make a second call to [sqlite3_reset()] 3632** in order to find the underlying cause of the problem. With the "v2" prepare 3633** interfaces, the underlying reason for the error is returned immediately. 3634** </li> 3635** 3636** <li> 3637** ^If the specific value bound to [parameter | host parameter] in the 3638** WHERE clause might influence the choice of query plan for a statement, 3639** then the statement will be automatically recompiled, as if there had been 3640** a schema change, on the first [sqlite3_step()] call following any change 3641** to the [sqlite3_bind_text | bindings] of that [parameter]. 3642** ^The specific value of WHERE-clause [parameter] might influence the 3643** choice of query plan if the parameter is the left-hand side of a [LIKE] 3644** or [GLOB] operator or if the parameter is compared to an indexed column 3645** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3646** </li> 3647** 3648** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 3649** the extra prepFlags parameter, which is a bit array consisting of zero or 3650** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 3651** sqlite3_prepare_v2() interface works exactly the same as 3652** sqlite3_prepare_v3() with a zero prepFlags parameter. 3653** </ol> 3654*/ 3655int sqlite3_prepare( 3656 sqlite3 *db, /* Database handle */ 3657 const char *zSql, /* SQL statement, UTF-8 encoded */ 3658 int nByte, /* Maximum length of zSql in bytes. */ 3659 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3660 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3661); 3662int sqlite3_prepare_v2( 3663 sqlite3 *db, /* Database handle */ 3664 const char *zSql, /* SQL statement, UTF-8 encoded */ 3665 int nByte, /* Maximum length of zSql in bytes. */ 3666 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3667 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3668); 3669int sqlite3_prepare_v3( 3670 sqlite3 *db, /* Database handle */ 3671 const char *zSql, /* SQL statement, UTF-8 encoded */ 3672 int nByte, /* Maximum length of zSql in bytes. */ 3673 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3674 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3675 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3676); 3677int sqlite3_prepare16( 3678 sqlite3 *db, /* Database handle */ 3679 const void *zSql, /* SQL statement, UTF-16 encoded */ 3680 int nByte, /* Maximum length of zSql in bytes. */ 3681 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3682 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3683); 3684int sqlite3_prepare16_v2( 3685 sqlite3 *db, /* Database handle */ 3686 const void *zSql, /* SQL statement, UTF-16 encoded */ 3687 int nByte, /* Maximum length of zSql in bytes. */ 3688 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3689 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3690); 3691int sqlite3_prepare16_v3( 3692 sqlite3 *db, /* Database handle */ 3693 const void *zSql, /* SQL statement, UTF-16 encoded */ 3694 int nByte, /* Maximum length of zSql in bytes. */ 3695 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3696 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3697 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3698); 3699 3700/* 3701** CAPI3REF: Retrieving Statement SQL 3702** METHOD: sqlite3_stmt 3703** 3704** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 3705** SQL text used to create [prepared statement] P if P was 3706** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 3707** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 3708** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 3709** string containing the SQL text of prepared statement P with 3710** [bound parameters] expanded. 3711** 3712** ^(For example, if a prepared statement is created using the SQL 3713** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 3714** and parameter :xyz is unbound, then sqlite3_sql() will return 3715** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 3716** will return "SELECT 2345,NULL".)^ 3717** 3718** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 3719** is available to hold the result, or if the result would exceed the 3720** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 3721** 3722** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 3723** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 3724** option causes sqlite3_expanded_sql() to always return NULL. 3725** 3726** ^The string returned by sqlite3_sql(P) is managed by SQLite and is 3727** automatically freed when the prepared statement is finalized. 3728** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 3729** is obtained from [sqlite3_malloc()] and must be free by the application 3730** by passing it to [sqlite3_free()]. 3731*/ 3732const char *sqlite3_sql(sqlite3_stmt *pStmt); 3733char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 3734 3735/* 3736** CAPI3REF: Determine If An SQL Statement Writes The Database 3737** METHOD: sqlite3_stmt 3738** 3739** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3740** and only if the [prepared statement] X makes no direct changes to 3741** the content of the database file. 3742** 3743** Note that [application-defined SQL functions] or 3744** [virtual tables] might change the database indirectly as a side effect. 3745** ^(For example, if an application defines a function "eval()" that 3746** calls [sqlite3_exec()], then the following SQL statement would 3747** change the database file through side-effects: 3748** 3749** <blockquote><pre> 3750** SELECT eval('DELETE FROM t1') FROM t2; 3751** </pre></blockquote> 3752** 3753** But because the [SELECT] statement does not change the database file 3754** directly, sqlite3_stmt_readonly() would still return true.)^ 3755** 3756** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3757** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3758** since the statements themselves do not actually modify the database but 3759** rather they control the timing of when other statements modify the 3760** database. ^The [ATTACH] and [DETACH] statements also cause 3761** sqlite3_stmt_readonly() to return true since, while those statements 3762** change the configuration of a database connection, they do not make 3763** changes to the content of the database files on disk. 3764** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 3765** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 3766** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 3767** sqlite3_stmt_readonly() returns false for those commands. 3768*/ 3769int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3770 3771/* 3772** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3773** METHOD: sqlite3_stmt 3774** 3775** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3776** [prepared statement] S has been stepped at least once using 3777** [sqlite3_step(S)] but has neither run to completion (returned 3778** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3779** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3780** interface returns false if S is a NULL pointer. If S is not a 3781** NULL pointer and is not a pointer to a valid [prepared statement] 3782** object, then the behavior is undefined and probably undesirable. 3783** 3784** This interface can be used in combination [sqlite3_next_stmt()] 3785** to locate all prepared statements associated with a database 3786** connection that are in need of being reset. This can be used, 3787** for example, in diagnostic routines to search for prepared 3788** statements that are holding a transaction open. 3789*/ 3790int sqlite3_stmt_busy(sqlite3_stmt*); 3791 3792/* 3793** CAPI3REF: Dynamically Typed Value Object 3794** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3795** 3796** SQLite uses the sqlite3_value object to represent all values 3797** that can be stored in a database table. SQLite uses dynamic typing 3798** for the values it stores. ^Values stored in sqlite3_value objects 3799** can be integers, floating point values, strings, BLOBs, or NULL. 3800** 3801** An sqlite3_value object may be either "protected" or "unprotected". 3802** Some interfaces require a protected sqlite3_value. Other interfaces 3803** will accept either a protected or an unprotected sqlite3_value. 3804** Every interface that accepts sqlite3_value arguments specifies 3805** whether or not it requires a protected sqlite3_value. The 3806** [sqlite3_value_dup()] interface can be used to construct a new 3807** protected sqlite3_value from an unprotected sqlite3_value. 3808** 3809** The terms "protected" and "unprotected" refer to whether or not 3810** a mutex is held. An internal mutex is held for a protected 3811** sqlite3_value object but no mutex is held for an unprotected 3812** sqlite3_value object. If SQLite is compiled to be single-threaded 3813** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3814** or if SQLite is run in one of reduced mutex modes 3815** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3816** then there is no distinction between protected and unprotected 3817** sqlite3_value objects and they can be used interchangeably. However, 3818** for maximum code portability it is recommended that applications 3819** still make the distinction between protected and unprotected 3820** sqlite3_value objects even when not strictly required. 3821** 3822** ^The sqlite3_value objects that are passed as parameters into the 3823** implementation of [application-defined SQL functions] are protected. 3824** ^The sqlite3_value object returned by 3825** [sqlite3_column_value()] is unprotected. 3826** Unprotected sqlite3_value objects may only be used with 3827** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3828** The [sqlite3_value_blob | sqlite3_value_type()] family of 3829** interfaces require protected sqlite3_value objects. 3830*/ 3831typedef struct sqlite3_value sqlite3_value; 3832 3833/* 3834** CAPI3REF: SQL Function Context Object 3835** 3836** The context in which an SQL function executes is stored in an 3837** sqlite3_context object. ^A pointer to an sqlite3_context object 3838** is always first parameter to [application-defined SQL functions]. 3839** The application-defined SQL function implementation will pass this 3840** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3841** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3842** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3843** and/or [sqlite3_set_auxdata()]. 3844*/ 3845typedef struct sqlite3_context sqlite3_context; 3846 3847/* 3848** CAPI3REF: Binding Values To Prepared Statements 3849** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3850** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3851** METHOD: sqlite3_stmt 3852** 3853** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3854** literals may be replaced by a [parameter] that matches one of following 3855** templates: 3856** 3857** <ul> 3858** <li> ? 3859** <li> ?NNN 3860** <li> :VVV 3861** <li> @VVV 3862** <li> $VVV 3863** </ul> 3864** 3865** In the templates above, NNN represents an integer literal, 3866** and VVV represents an alphanumeric identifier.)^ ^The values of these 3867** parameters (also called "host parameter names" or "SQL parameters") 3868** can be set using the sqlite3_bind_*() routines defined here. 3869** 3870** ^The first argument to the sqlite3_bind_*() routines is always 3871** a pointer to the [sqlite3_stmt] object returned from 3872** [sqlite3_prepare_v2()] or its variants. 3873** 3874** ^The second argument is the index of the SQL parameter to be set. 3875** ^The leftmost SQL parameter has an index of 1. ^When the same named 3876** SQL parameter is used more than once, second and subsequent 3877** occurrences have the same index as the first occurrence. 3878** ^The index for named parameters can be looked up using the 3879** [sqlite3_bind_parameter_index()] API if desired. ^The index 3880** for "?NNN" parameters is the value of NNN. 3881** ^The NNN value must be between 1 and the [sqlite3_limit()] 3882** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3883** 3884** ^The third argument is the value to bind to the parameter. 3885** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3886** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3887** is ignored and the end result is the same as sqlite3_bind_null(). 3888** 3889** ^(In those routines that have a fourth argument, its value is the 3890** number of bytes in the parameter. To be clear: the value is the 3891** number of <u>bytes</u> in the value, not the number of characters.)^ 3892** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3893** is negative, then the length of the string is 3894** the number of bytes up to the first zero terminator. 3895** If the fourth parameter to sqlite3_bind_blob() is negative, then 3896** the behavior is undefined. 3897** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3898** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3899** that parameter must be the byte offset 3900** where the NUL terminator would occur assuming the string were NUL 3901** terminated. If any NUL characters occur at byte offsets less than 3902** the value of the fourth parameter then the resulting string value will 3903** contain embedded NULs. The result of expressions involving strings 3904** with embedded NULs is undefined. 3905** 3906** ^The fifth argument to the BLOB and string binding interfaces 3907** is a destructor used to dispose of the BLOB or 3908** string after SQLite has finished with it. ^The destructor is called 3909** to dispose of the BLOB or string even if the call to bind API fails. 3910** ^If the fifth argument is 3911** the special value [SQLITE_STATIC], then SQLite assumes that the 3912** information is in static, unmanaged space and does not need to be freed. 3913** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3914** SQLite makes its own private copy of the data immediately, before 3915** the sqlite3_bind_*() routine returns. 3916** 3917** ^The sixth argument to sqlite3_bind_text64() must be one of 3918** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3919** to specify the encoding of the text in the third parameter. If 3920** the sixth argument to sqlite3_bind_text64() is not one of the 3921** allowed values shown above, or if the text encoding is different 3922** from the encoding specified by the sixth parameter, then the behavior 3923** is undefined. 3924** 3925** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3926** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3927** (just an integer to hold its size) while it is being processed. 3928** Zeroblobs are intended to serve as placeholders for BLOBs whose 3929** content is later written using 3930** [sqlite3_blob_open | incremental BLOB I/O] routines. 3931** ^A negative value for the zeroblob results in a zero-length BLOB. 3932** 3933** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 3934** [prepared statement] S to have an SQL value of NULL, but to also be 3935** associated with the pointer P of type T. ^D is either a NULL pointer or 3936** a pointer to a destructor function for P. ^SQLite will invoke the 3937** destructor D with a single argument of P when it is finished using 3938** P. The T parameter should be a static string, preferably a string 3939** literal. The sqlite3_bind_pointer() routine is part of the 3940** [pointer passing interface] added for SQLite 3.20.0. 3941** 3942** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3943** for the [prepared statement] or with a prepared statement for which 3944** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3945** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3946** routine is passed a [prepared statement] that has been finalized, the 3947** result is undefined and probably harmful. 3948** 3949** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3950** ^Unbound parameters are interpreted as NULL. 3951** 3952** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3953** [error code] if anything goes wrong. 3954** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3955** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3956** [SQLITE_MAX_LENGTH]. 3957** ^[SQLITE_RANGE] is returned if the parameter 3958** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3959** 3960** See also: [sqlite3_bind_parameter_count()], 3961** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3962*/ 3963int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3964int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3965 void(*)(void*)); 3966int sqlite3_bind_double(sqlite3_stmt*, int, double); 3967int sqlite3_bind_int(sqlite3_stmt*, int, int); 3968int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3969int sqlite3_bind_null(sqlite3_stmt*, int); 3970int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3971int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3972int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3973 void(*)(void*), unsigned char encoding); 3974int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3975int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 3976int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3977int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 3978 3979/* 3980** CAPI3REF: Number Of SQL Parameters 3981** METHOD: sqlite3_stmt 3982** 3983** ^This routine can be used to find the number of [SQL parameters] 3984** in a [prepared statement]. SQL parameters are tokens of the 3985** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3986** placeholders for values that are [sqlite3_bind_blob | bound] 3987** to the parameters at a later time. 3988** 3989** ^(This routine actually returns the index of the largest (rightmost) 3990** parameter. For all forms except ?NNN, this will correspond to the 3991** number of unique parameters. If parameters of the ?NNN form are used, 3992** there may be gaps in the list.)^ 3993** 3994** See also: [sqlite3_bind_blob|sqlite3_bind()], 3995** [sqlite3_bind_parameter_name()], and 3996** [sqlite3_bind_parameter_index()]. 3997*/ 3998int sqlite3_bind_parameter_count(sqlite3_stmt*); 3999 4000/* 4001** CAPI3REF: Name Of A Host Parameter 4002** METHOD: sqlite3_stmt 4003** 4004** ^The sqlite3_bind_parameter_name(P,N) interface returns 4005** the name of the N-th [SQL parameter] in the [prepared statement] P. 4006** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 4007** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 4008** respectively. 4009** In other words, the initial ":" or "$" or "@" or "?" 4010** is included as part of the name.)^ 4011** ^Parameters of the form "?" without a following integer have no name 4012** and are referred to as "nameless" or "anonymous parameters". 4013** 4014** ^The first host parameter has an index of 1, not 0. 4015** 4016** ^If the value N is out of range or if the N-th parameter is 4017** nameless, then NULL is returned. ^The returned string is 4018** always in UTF-8 encoding even if the named parameter was 4019** originally specified as UTF-16 in [sqlite3_prepare16()], 4020** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4021** 4022** See also: [sqlite3_bind_blob|sqlite3_bind()], 4023** [sqlite3_bind_parameter_count()], and 4024** [sqlite3_bind_parameter_index()]. 4025*/ 4026const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 4027 4028/* 4029** CAPI3REF: Index Of A Parameter With A Given Name 4030** METHOD: sqlite3_stmt 4031** 4032** ^Return the index of an SQL parameter given its name. ^The 4033** index value returned is suitable for use as the second 4034** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4035** is returned if no matching parameter is found. ^The parameter 4036** name must be given in UTF-8 even if the original statement 4037** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4038** [sqlite3_prepare16_v3()]. 4039** 4040** See also: [sqlite3_bind_blob|sqlite3_bind()], 4041** [sqlite3_bind_parameter_count()], and 4042** [sqlite3_bind_parameter_name()]. 4043*/ 4044int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4045 4046/* 4047** CAPI3REF: Reset All Bindings On A Prepared Statement 4048** METHOD: sqlite3_stmt 4049** 4050** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4051** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4052** ^Use this routine to reset all host parameters to NULL. 4053*/ 4054int sqlite3_clear_bindings(sqlite3_stmt*); 4055 4056/* 4057** CAPI3REF: Number Of Columns In A Result Set 4058** METHOD: sqlite3_stmt 4059** 4060** ^Return the number of columns in the result set returned by the 4061** [prepared statement]. ^If this routine returns 0, that means the 4062** [prepared statement] returns no data (for example an [UPDATE]). 4063** ^However, just because this routine returns a positive number does not 4064** mean that one or more rows of data will be returned. ^A SELECT statement 4065** will always have a positive sqlite3_column_count() but depending on the 4066** WHERE clause constraints and the table content, it might return no rows. 4067** 4068** See also: [sqlite3_data_count()] 4069*/ 4070int sqlite3_column_count(sqlite3_stmt *pStmt); 4071 4072/* 4073** CAPI3REF: Column Names In A Result Set 4074** METHOD: sqlite3_stmt 4075** 4076** ^These routines return the name assigned to a particular column 4077** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4078** interface returns a pointer to a zero-terminated UTF-8 string 4079** and sqlite3_column_name16() returns a pointer to a zero-terminated 4080** UTF-16 string. ^The first parameter is the [prepared statement] 4081** that implements the [SELECT] statement. ^The second parameter is the 4082** column number. ^The leftmost column is number 0. 4083** 4084** ^The returned string pointer is valid until either the [prepared statement] 4085** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4086** reprepared by the first call to [sqlite3_step()] for a particular run 4087** or until the next call to 4088** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4089** 4090** ^If sqlite3_malloc() fails during the processing of either routine 4091** (for example during a conversion from UTF-8 to UTF-16) then a 4092** NULL pointer is returned. 4093** 4094** ^The name of a result column is the value of the "AS" clause for 4095** that column, if there is an AS clause. If there is no AS clause 4096** then the name of the column is unspecified and may change from 4097** one release of SQLite to the next. 4098*/ 4099const char *sqlite3_column_name(sqlite3_stmt*, int N); 4100const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4101 4102/* 4103** CAPI3REF: Source Of Data In A Query Result 4104** METHOD: sqlite3_stmt 4105** 4106** ^These routines provide a means to determine the database, table, and 4107** table column that is the origin of a particular result column in 4108** [SELECT] statement. 4109** ^The name of the database or table or column can be returned as 4110** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4111** the database name, the _table_ routines return the table name, and 4112** the origin_ routines return the column name. 4113** ^The returned string is valid until the [prepared statement] is destroyed 4114** using [sqlite3_finalize()] or until the statement is automatically 4115** reprepared by the first call to [sqlite3_step()] for a particular run 4116** or until the same information is requested 4117** again in a different encoding. 4118** 4119** ^The names returned are the original un-aliased names of the 4120** database, table, and column. 4121** 4122** ^The first argument to these interfaces is a [prepared statement]. 4123** ^These functions return information about the Nth result column returned by 4124** the statement, where N is the second function argument. 4125** ^The left-most column is column 0 for these routines. 4126** 4127** ^If the Nth column returned by the statement is an expression or 4128** subquery and is not a column value, then all of these functions return 4129** NULL. ^These routine might also return NULL if a memory allocation error 4130** occurs. ^Otherwise, they return the name of the attached database, table, 4131** or column that query result column was extracted from. 4132** 4133** ^As with all other SQLite APIs, those whose names end with "16" return 4134** UTF-16 encoded strings and the other functions return UTF-8. 4135** 4136** ^These APIs are only available if the library was compiled with the 4137** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4138** 4139** If two or more threads call one or more of these routines against the same 4140** prepared statement and column at the same time then the results are 4141** undefined. 4142** 4143** If two or more threads call one or more 4144** [sqlite3_column_database_name | column metadata interfaces] 4145** for the same [prepared statement] and result column 4146** at the same time then the results are undefined. 4147*/ 4148const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4149const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4150const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4151const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4152const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4153const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4154 4155/* 4156** CAPI3REF: Declared Datatype Of A Query Result 4157** METHOD: sqlite3_stmt 4158** 4159** ^(The first parameter is a [prepared statement]. 4160** If this statement is a [SELECT] statement and the Nth column of the 4161** returned result set of that [SELECT] is a table column (not an 4162** expression or subquery) then the declared type of the table 4163** column is returned.)^ ^If the Nth column of the result set is an 4164** expression or subquery, then a NULL pointer is returned. 4165** ^The returned string is always UTF-8 encoded. 4166** 4167** ^(For example, given the database schema: 4168** 4169** CREATE TABLE t1(c1 VARIANT); 4170** 4171** and the following statement to be compiled: 4172** 4173** SELECT c1 + 1, c1 FROM t1; 4174** 4175** this routine would return the string "VARIANT" for the second result 4176** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4177** 4178** ^SQLite uses dynamic run-time typing. ^So just because a column 4179** is declared to contain a particular type does not mean that the 4180** data stored in that column is of the declared type. SQLite is 4181** strongly typed, but the typing is dynamic not static. ^Type 4182** is associated with individual values, not with the containers 4183** used to hold those values. 4184*/ 4185const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4186const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4187 4188/* 4189** CAPI3REF: Evaluate An SQL Statement 4190** METHOD: sqlite3_stmt 4191** 4192** After a [prepared statement] has been prepared using any of 4193** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4194** or [sqlite3_prepare16_v3()] or one of the legacy 4195** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4196** must be called one or more times to evaluate the statement. 4197** 4198** The details of the behavior of the sqlite3_step() interface depend 4199** on whether the statement was prepared using the newer "vX" interfaces 4200** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4201** [sqlite3_prepare16_v2()] or the older legacy 4202** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4203** new "vX" interface is recommended for new applications but the legacy 4204** interface will continue to be supported. 4205** 4206** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4207** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4208** ^With the "v2" interface, any of the other [result codes] or 4209** [extended result codes] might be returned as well. 4210** 4211** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4212** database locks it needs to do its job. ^If the statement is a [COMMIT] 4213** or occurs outside of an explicit transaction, then you can retry the 4214** statement. If the statement is not a [COMMIT] and occurs within an 4215** explicit transaction then you should rollback the transaction before 4216** continuing. 4217** 4218** ^[SQLITE_DONE] means that the statement has finished executing 4219** successfully. sqlite3_step() should not be called again on this virtual 4220** machine without first calling [sqlite3_reset()] to reset the virtual 4221** machine back to its initial state. 4222** 4223** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4224** is returned each time a new row of data is ready for processing by the 4225** caller. The values may be accessed using the [column access functions]. 4226** sqlite3_step() is called again to retrieve the next row of data. 4227** 4228** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4229** violation) has occurred. sqlite3_step() should not be called again on 4230** the VM. More information may be found by calling [sqlite3_errmsg()]. 4231** ^With the legacy interface, a more specific error code (for example, 4232** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4233** can be obtained by calling [sqlite3_reset()] on the 4234** [prepared statement]. ^In the "v2" interface, 4235** the more specific error code is returned directly by sqlite3_step(). 4236** 4237** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4238** Perhaps it was called on a [prepared statement] that has 4239** already been [sqlite3_finalize | finalized] or on one that had 4240** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4241** be the case that the same database connection is being used by two or 4242** more threads at the same moment in time. 4243** 4244** For all versions of SQLite up to and including 3.6.23.1, a call to 4245** [sqlite3_reset()] was required after sqlite3_step() returned anything 4246** other than [SQLITE_ROW] before any subsequent invocation of 4247** sqlite3_step(). Failure to reset the prepared statement using 4248** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4249** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4250** sqlite3_step() began 4251** calling [sqlite3_reset()] automatically in this circumstance rather 4252** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4253** break because any application that ever receives an SQLITE_MISUSE error 4254** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4255** can be used to restore the legacy behavior. 4256** 4257** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4258** API always returns a generic error code, [SQLITE_ERROR], following any 4259** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4260** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4261** specific [error codes] that better describes the error. 4262** We admit that this is a goofy design. The problem has been fixed 4263** with the "v2" interface. If you prepare all of your SQL statements 4264** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4265** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4266** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4267** then the more specific [error codes] are returned directly 4268** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4269*/ 4270int sqlite3_step(sqlite3_stmt*); 4271 4272/* 4273** CAPI3REF: Number of columns in a result set 4274** METHOD: sqlite3_stmt 4275** 4276** ^The sqlite3_data_count(P) interface returns the number of columns in the 4277** current row of the result set of [prepared statement] P. 4278** ^If prepared statement P does not have results ready to return 4279** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 4280** interfaces) then sqlite3_data_count(P) returns 0. 4281** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4282** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4283** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4284** will return non-zero if previous call to [sqlite3_step](P) returned 4285** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4286** where it always returns zero since each step of that multi-step 4287** pragma returns 0 columns of data. 4288** 4289** See also: [sqlite3_column_count()] 4290*/ 4291int sqlite3_data_count(sqlite3_stmt *pStmt); 4292 4293/* 4294** CAPI3REF: Fundamental Datatypes 4295** KEYWORDS: SQLITE_TEXT 4296** 4297** ^(Every value in SQLite has one of five fundamental datatypes: 4298** 4299** <ul> 4300** <li> 64-bit signed integer 4301** <li> 64-bit IEEE floating point number 4302** <li> string 4303** <li> BLOB 4304** <li> NULL 4305** </ul>)^ 4306** 4307** These constants are codes for each of those types. 4308** 4309** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4310** for a completely different meaning. Software that links against both 4311** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4312** SQLITE_TEXT. 4313*/ 4314#define SQLITE_INTEGER 1 4315#define SQLITE_FLOAT 2 4316#define SQLITE_BLOB 4 4317#define SQLITE_NULL 5 4318#ifdef SQLITE_TEXT 4319# undef SQLITE_TEXT 4320#else 4321# define SQLITE_TEXT 3 4322#endif 4323#define SQLITE3_TEXT 3 4324 4325/* 4326** CAPI3REF: Result Values From A Query 4327** KEYWORDS: {column access functions} 4328** METHOD: sqlite3_stmt 4329** 4330** <b>Summary:</b> 4331** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4332** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4333** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4334** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4335** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4336** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4337** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4338** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4339** [sqlite3_value|unprotected sqlite3_value] object. 4340** <tr><td> <td> <td> 4341** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4342** or a UTF-8 TEXT result in bytes 4343** <tr><td><b>sqlite3_column_bytes16 </b> 4344** <td>→ <td>Size of UTF-16 4345** TEXT in bytes 4346** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4347** datatype of the result 4348** </table></blockquote> 4349** 4350** <b>Details:</b> 4351** 4352** ^These routines return information about a single column of the current 4353** result row of a query. ^In every case the first argument is a pointer 4354** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4355** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4356** and the second argument is the index of the column for which information 4357** should be returned. ^The leftmost column of the result set has the index 0. 4358** ^The number of columns in the result can be determined using 4359** [sqlite3_column_count()]. 4360** 4361** If the SQL statement does not currently point to a valid row, or if the 4362** column index is out of range, the result is undefined. 4363** These routines may only be called when the most recent call to 4364** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4365** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4366** If any of these routines are called after [sqlite3_reset()] or 4367** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4368** something other than [SQLITE_ROW], the results are undefined. 4369** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4370** are called from a different thread while any of these routines 4371** are pending, then the results are undefined. 4372** 4373** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4374** each return the value of a result column in a specific data format. If 4375** the result column is not initially in the requested format (for example, 4376** if the query returns an integer but the sqlite3_column_text() interface 4377** is used to extract the value) then an automatic type conversion is performed. 4378** 4379** ^The sqlite3_column_type() routine returns the 4380** [SQLITE_INTEGER | datatype code] for the initial data type 4381** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4382** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4383** The return value of sqlite3_column_type() can be used to decide which 4384** of the first six interface should be used to extract the column value. 4385** The value returned by sqlite3_column_type() is only meaningful if no 4386** automatic type conversions have occurred for the value in question. 4387** After a type conversion, the result of calling sqlite3_column_type() 4388** is undefined, though harmless. Future 4389** versions of SQLite may change the behavior of sqlite3_column_type() 4390** following a type conversion. 4391** 4392** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4393** or sqlite3_column_bytes16() interfaces can be used to determine the size 4394** of that BLOB or string. 4395** 4396** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4397** routine returns the number of bytes in that BLOB or string. 4398** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4399** the string to UTF-8 and then returns the number of bytes. 4400** ^If the result is a numeric value then sqlite3_column_bytes() uses 4401** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4402** the number of bytes in that string. 4403** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4404** 4405** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4406** routine returns the number of bytes in that BLOB or string. 4407** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4408** the string to UTF-16 and then returns the number of bytes. 4409** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4410** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4411** the number of bytes in that string. 4412** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4413** 4414** ^The values returned by [sqlite3_column_bytes()] and 4415** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4416** of the string. ^For clarity: the values returned by 4417** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4418** bytes in the string, not the number of characters. 4419** 4420** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4421** even empty strings, are always zero-terminated. ^The return 4422** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4423** 4424** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4425** [unprotected sqlite3_value] object. In a multithreaded environment, 4426** an unprotected sqlite3_value object may only be used safely with 4427** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4428** If the [unprotected sqlite3_value] object returned by 4429** [sqlite3_column_value()] is used in any other way, including calls 4430** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4431** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4432** Hence, the sqlite3_column_value() interface 4433** is normally only useful within the implementation of 4434** [application-defined SQL functions] or [virtual tables], not within 4435** top-level application code. 4436** 4437** The these routines may attempt to convert the datatype of the result. 4438** ^For example, if the internal representation is FLOAT and a text result 4439** is requested, [sqlite3_snprintf()] is used internally to perform the 4440** conversion automatically. ^(The following table details the conversions 4441** that are applied: 4442** 4443** <blockquote> 4444** <table border="1"> 4445** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4446** 4447** <tr><td> NULL <td> INTEGER <td> Result is 0 4448** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4449** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4450** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4451** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4452** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4453** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4454** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4455** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4456** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4457** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4458** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4459** <tr><td> TEXT <td> BLOB <td> No change 4460** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4461** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4462** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4463** </table> 4464** </blockquote>)^ 4465** 4466** Note that when type conversions occur, pointers returned by prior 4467** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4468** sqlite3_column_text16() may be invalidated. 4469** Type conversions and pointer invalidations might occur 4470** in the following cases: 4471** 4472** <ul> 4473** <li> The initial content is a BLOB and sqlite3_column_text() or 4474** sqlite3_column_text16() is called. A zero-terminator might 4475** need to be added to the string.</li> 4476** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4477** sqlite3_column_text16() is called. The content must be converted 4478** to UTF-16.</li> 4479** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4480** sqlite3_column_text() is called. The content must be converted 4481** to UTF-8.</li> 4482** </ul> 4483** 4484** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4485** not invalidate a prior pointer, though of course the content of the buffer 4486** that the prior pointer references will have been modified. Other kinds 4487** of conversion are done in place when it is possible, but sometimes they 4488** are not possible and in those cases prior pointers are invalidated. 4489** 4490** The safest policy is to invoke these routines 4491** in one of the following ways: 4492** 4493** <ul> 4494** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4495** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4496** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4497** </ul> 4498** 4499** In other words, you should call sqlite3_column_text(), 4500** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4501** into the desired format, then invoke sqlite3_column_bytes() or 4502** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4503** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4504** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4505** with calls to sqlite3_column_bytes(). 4506** 4507** ^The pointers returned are valid until a type conversion occurs as 4508** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4509** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4510** and BLOBs is freed automatically. Do not pass the pointers returned 4511** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4512** [sqlite3_free()]. 4513** 4514** ^(If a memory allocation error occurs during the evaluation of any 4515** of these routines, a default value is returned. The default value 4516** is either the integer 0, the floating point number 0.0, or a NULL 4517** pointer. Subsequent calls to [sqlite3_errcode()] will return 4518** [SQLITE_NOMEM].)^ 4519*/ 4520const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4521double sqlite3_column_double(sqlite3_stmt*, int iCol); 4522int sqlite3_column_int(sqlite3_stmt*, int iCol); 4523sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4524const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4525const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4526sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4527int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4528int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4529int sqlite3_column_type(sqlite3_stmt*, int iCol); 4530 4531/* 4532** CAPI3REF: Destroy A Prepared Statement Object 4533** DESTRUCTOR: sqlite3_stmt 4534** 4535** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4536** ^If the most recent evaluation of the statement encountered no errors 4537** or if the statement is never been evaluated, then sqlite3_finalize() returns 4538** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4539** sqlite3_finalize(S) returns the appropriate [error code] or 4540** [extended error code]. 4541** 4542** ^The sqlite3_finalize(S) routine can be called at any point during 4543** the life cycle of [prepared statement] S: 4544** before statement S is ever evaluated, after 4545** one or more calls to [sqlite3_reset()], or after any call 4546** to [sqlite3_step()] regardless of whether or not the statement has 4547** completed execution. 4548** 4549** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4550** 4551** The application must finalize every [prepared statement] in order to avoid 4552** resource leaks. It is a grievous error for the application to try to use 4553** a prepared statement after it has been finalized. Any use of a prepared 4554** statement after it has been finalized can result in undefined and 4555** undesirable behavior such as segfaults and heap corruption. 4556*/ 4557int sqlite3_finalize(sqlite3_stmt *pStmt); 4558 4559/* 4560** CAPI3REF: Reset A Prepared Statement Object 4561** METHOD: sqlite3_stmt 4562** 4563** The sqlite3_reset() function is called to reset a [prepared statement] 4564** object back to its initial state, ready to be re-executed. 4565** ^Any SQL statement variables that had values bound to them using 4566** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4567** Use [sqlite3_clear_bindings()] to reset the bindings. 4568** 4569** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4570** back to the beginning of its program. 4571** 4572** ^If the most recent call to [sqlite3_step(S)] for the 4573** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4574** or if [sqlite3_step(S)] has never before been called on S, 4575** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4576** 4577** ^If the most recent call to [sqlite3_step(S)] for the 4578** [prepared statement] S indicated an error, then 4579** [sqlite3_reset(S)] returns an appropriate [error code]. 4580** 4581** ^The [sqlite3_reset(S)] interface does not change the values 4582** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4583*/ 4584int sqlite3_reset(sqlite3_stmt *pStmt); 4585 4586/* 4587** CAPI3REF: Create Or Redefine SQL Functions 4588** KEYWORDS: {function creation routines} 4589** KEYWORDS: {application-defined SQL function} 4590** KEYWORDS: {application-defined SQL functions} 4591** METHOD: sqlite3 4592** 4593** ^These functions (collectively known as "function creation routines") 4594** are used to add SQL functions or aggregates or to redefine the behavior 4595** of existing SQL functions or aggregates. The only differences between 4596** these routines are the text encoding expected for 4597** the second parameter (the name of the function being created) 4598** and the presence or absence of a destructor callback for 4599** the application data pointer. 4600** 4601** ^The first parameter is the [database connection] to which the SQL 4602** function is to be added. ^If an application uses more than one database 4603** connection then application-defined SQL functions must be added 4604** to each database connection separately. 4605** 4606** ^The second parameter is the name of the SQL function to be created or 4607** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4608** representation, exclusive of the zero-terminator. ^Note that the name 4609** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4610** ^Any attempt to create a function with a longer name 4611** will result in [SQLITE_MISUSE] being returned. 4612** 4613** ^The third parameter (nArg) 4614** is the number of arguments that the SQL function or 4615** aggregate takes. ^If this parameter is -1, then the SQL function or 4616** aggregate may take any number of arguments between 0 and the limit 4617** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4618** parameter is less than -1 or greater than 127 then the behavior is 4619** undefined. 4620** 4621** ^The fourth parameter, eTextRep, specifies what 4622** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4623** its parameters. The application should set this parameter to 4624** [SQLITE_UTF16LE] if the function implementation invokes 4625** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4626** implementation invokes [sqlite3_value_text16be()] on an input, or 4627** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4628** otherwise. ^The same SQL function may be registered multiple times using 4629** different preferred text encodings, with different implementations for 4630** each encoding. 4631** ^When multiple implementations of the same function are available, SQLite 4632** will pick the one that involves the least amount of data conversion. 4633** 4634** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4635** to signal that the function will always return the same result given 4636** the same inputs within a single SQL statement. Most SQL functions are 4637** deterministic. The built-in [random()] SQL function is an example of a 4638** function that is not deterministic. The SQLite query planner is able to 4639** perform additional optimizations on deterministic functions, so use 4640** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4641** 4642** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4643** function can gain access to this pointer using [sqlite3_user_data()].)^ 4644** 4645** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4646** pointers to C-language functions that implement the SQL function or 4647** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4648** callback only; NULL pointers must be passed as the xStep and xFinal 4649** parameters. ^An aggregate SQL function requires an implementation of xStep 4650** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4651** SQL function or aggregate, pass NULL pointers for all three function 4652** callbacks. 4653** 4654** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4655** then it is destructor for the application data pointer. 4656** The destructor is invoked when the function is deleted, either by being 4657** overloaded or when the database connection closes.)^ 4658** ^The destructor is also invoked if the call to 4659** sqlite3_create_function_v2() fails. 4660** ^When the destructor callback of the tenth parameter is invoked, it 4661** is passed a single argument which is a copy of the application data 4662** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4663** 4664** ^It is permitted to register multiple implementations of the same 4665** functions with the same name but with either differing numbers of 4666** arguments or differing preferred text encodings. ^SQLite will use 4667** the implementation that most closely matches the way in which the 4668** SQL function is used. ^A function implementation with a non-negative 4669** nArg parameter is a better match than a function implementation with 4670** a negative nArg. ^A function where the preferred text encoding 4671** matches the database encoding is a better 4672** match than a function where the encoding is different. 4673** ^A function where the encoding difference is between UTF16le and UTF16be 4674** is a closer match than a function where the encoding difference is 4675** between UTF8 and UTF16. 4676** 4677** ^Built-in functions may be overloaded by new application-defined functions. 4678** 4679** ^An application-defined function is permitted to call other 4680** SQLite interfaces. However, such calls must not 4681** close the database connection nor finalize or reset the prepared 4682** statement in which the function is running. 4683*/ 4684int sqlite3_create_function( 4685 sqlite3 *db, 4686 const char *zFunctionName, 4687 int nArg, 4688 int eTextRep, 4689 void *pApp, 4690 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4691 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4692 void (*xFinal)(sqlite3_context*) 4693); 4694int sqlite3_create_function16( 4695 sqlite3 *db, 4696 const void *zFunctionName, 4697 int nArg, 4698 int eTextRep, 4699 void *pApp, 4700 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4701 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4702 void (*xFinal)(sqlite3_context*) 4703); 4704int sqlite3_create_function_v2( 4705 sqlite3 *db, 4706 const char *zFunctionName, 4707 int nArg, 4708 int eTextRep, 4709 void *pApp, 4710 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4711 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4712 void (*xFinal)(sqlite3_context*), 4713 void(*xDestroy)(void*) 4714); 4715 4716/* 4717** CAPI3REF: Text Encodings 4718** 4719** These constant define integer codes that represent the various 4720** text encodings supported by SQLite. 4721*/ 4722#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4723#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4724#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4725#define SQLITE_UTF16 4 /* Use native byte order */ 4726#define SQLITE_ANY 5 /* Deprecated */ 4727#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4728 4729/* 4730** CAPI3REF: Function Flags 4731** 4732** These constants may be ORed together with the 4733** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4734** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4735** [sqlite3_create_function_v2()]. 4736*/ 4737#define SQLITE_DETERMINISTIC 0x800 4738 4739/* 4740** CAPI3REF: Deprecated Functions 4741** DEPRECATED 4742** 4743** These functions are [deprecated]. In order to maintain 4744** backwards compatibility with older code, these functions continue 4745** to be supported. However, new applications should avoid 4746** the use of these functions. To encourage programmers to avoid 4747** these functions, we will not explain what they do. 4748*/ 4749#ifndef SQLITE_OMIT_DEPRECATED 4750SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4751SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4752SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4753SQLITE_DEPRECATED int sqlite3_global_recover(void); 4754SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4755SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4756 void*,sqlite3_int64); 4757#endif 4758 4759/* 4760** CAPI3REF: Obtaining SQL Values 4761** METHOD: sqlite3_value 4762** 4763** <b>Summary:</b> 4764** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4765** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 4766** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 4767** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 4768** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 4769** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 4770** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 4771** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 4772** the native byteorder 4773** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 4774** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 4775** <tr><td> <td> <td> 4776** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 4777** or a UTF-8 TEXT in bytes 4778** <tr><td><b>sqlite3_value_bytes16 </b> 4779** <td>→ <td>Size of UTF-16 4780** TEXT in bytes 4781** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 4782** datatype of the value 4783** <tr><td><b>sqlite3_value_numeric_type </b> 4784** <td>→ <td>Best numeric datatype of the value 4785** </table></blockquote> 4786** 4787** <b>Details:</b> 4788** 4789** These routines extract type, size, and content information from 4790** [protected sqlite3_value] objects. Protected sqlite3_value objects 4791** are used to pass parameter information into implementation of 4792** [application-defined SQL functions] and [virtual tables]. 4793** 4794** These routines work only with [protected sqlite3_value] objects. 4795** Any attempt to use these routines on an [unprotected sqlite3_value] 4796** is not threadsafe. 4797** 4798** ^These routines work just like the corresponding [column access functions] 4799** except that these routines take a single [protected sqlite3_value] object 4800** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4801** 4802** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4803** in the native byte-order of the host machine. ^The 4804** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4805** extract UTF-16 strings as big-endian and little-endian respectively. 4806** 4807** ^If [sqlite3_value] object V was initialized 4808** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 4809** and if X and Y are strings that compare equal according to strcmp(X,Y), 4810** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 4811** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 4812** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 4813** 4814** ^(The sqlite3_value_type(V) interface returns the 4815** [SQLITE_INTEGER | datatype code] for the initial datatype of the 4816** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 4817** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 4818** Other interfaces might change the datatype for an sqlite3_value object. 4819** For example, if the datatype is initially SQLITE_INTEGER and 4820** sqlite3_value_text(V) is called to extract a text value for that 4821** integer, then subsequent calls to sqlite3_value_type(V) might return 4822** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 4823** occurs is undefined and may change from one release of SQLite to the next. 4824** 4825** ^(The sqlite3_value_numeric_type() interface attempts to apply 4826** numeric affinity to the value. This means that an attempt is 4827** made to convert the value to an integer or floating point. If 4828** such a conversion is possible without loss of information (in other 4829** words, if the value is a string that looks like a number) 4830** then the conversion is performed. Otherwise no conversion occurs. 4831** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4832** 4833** Please pay particular attention to the fact that the pointer returned 4834** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4835** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4836** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4837** or [sqlite3_value_text16()]. 4838** 4839** These routines must be called from the same thread as 4840** the SQL function that supplied the [sqlite3_value*] parameters. 4841*/ 4842const void *sqlite3_value_blob(sqlite3_value*); 4843double sqlite3_value_double(sqlite3_value*); 4844int sqlite3_value_int(sqlite3_value*); 4845sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4846void *sqlite3_value_pointer(sqlite3_value*, const char*); 4847const unsigned char *sqlite3_value_text(sqlite3_value*); 4848const void *sqlite3_value_text16(sqlite3_value*); 4849const void *sqlite3_value_text16le(sqlite3_value*); 4850const void *sqlite3_value_text16be(sqlite3_value*); 4851int sqlite3_value_bytes(sqlite3_value*); 4852int sqlite3_value_bytes16(sqlite3_value*); 4853int sqlite3_value_type(sqlite3_value*); 4854int sqlite3_value_numeric_type(sqlite3_value*); 4855 4856/* 4857** CAPI3REF: Finding The Subtype Of SQL Values 4858** METHOD: sqlite3_value 4859** 4860** The sqlite3_value_subtype(V) function returns the subtype for 4861** an [application-defined SQL function] argument V. The subtype 4862** information can be used to pass a limited amount of context from 4863** one SQL function to another. Use the [sqlite3_result_subtype()] 4864** routine to set the subtype for the return value of an SQL function. 4865*/ 4866unsigned int sqlite3_value_subtype(sqlite3_value*); 4867 4868/* 4869** CAPI3REF: Copy And Free SQL Values 4870** METHOD: sqlite3_value 4871** 4872** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 4873** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 4874** is a [protected sqlite3_value] object even if the input is not. 4875** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 4876** memory allocation fails. 4877** 4878** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 4879** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 4880** then sqlite3_value_free(V) is a harmless no-op. 4881*/ 4882sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 4883void sqlite3_value_free(sqlite3_value*); 4884 4885/* 4886** CAPI3REF: Obtain Aggregate Function Context 4887** METHOD: sqlite3_context 4888** 4889** Implementations of aggregate SQL functions use this 4890** routine to allocate memory for storing their state. 4891** 4892** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4893** for a particular aggregate function, SQLite 4894** allocates N of memory, zeroes out that memory, and returns a pointer 4895** to the new memory. ^On second and subsequent calls to 4896** sqlite3_aggregate_context() for the same aggregate function instance, 4897** the same buffer is returned. Sqlite3_aggregate_context() is normally 4898** called once for each invocation of the xStep callback and then one 4899** last time when the xFinal callback is invoked. ^(When no rows match 4900** an aggregate query, the xStep() callback of the aggregate function 4901** implementation is never called and xFinal() is called exactly once. 4902** In those cases, sqlite3_aggregate_context() might be called for the 4903** first time from within xFinal().)^ 4904** 4905** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4906** when first called if N is less than or equal to zero or if a memory 4907** allocate error occurs. 4908** 4909** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4910** determined by the N parameter on first successful call. Changing the 4911** value of N in subsequent call to sqlite3_aggregate_context() within 4912** the same aggregate function instance will not resize the memory 4913** allocation.)^ Within the xFinal callback, it is customary to set 4914** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4915** pointless memory allocations occur. 4916** 4917** ^SQLite automatically frees the memory allocated by 4918** sqlite3_aggregate_context() when the aggregate query concludes. 4919** 4920** The first parameter must be a copy of the 4921** [sqlite3_context | SQL function context] that is the first parameter 4922** to the xStep or xFinal callback routine that implements the aggregate 4923** function. 4924** 4925** This routine must be called from the same thread in which 4926** the aggregate SQL function is running. 4927*/ 4928void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4929 4930/* 4931** CAPI3REF: User Data For Functions 4932** METHOD: sqlite3_context 4933** 4934** ^The sqlite3_user_data() interface returns a copy of 4935** the pointer that was the pUserData parameter (the 5th parameter) 4936** of the [sqlite3_create_function()] 4937** and [sqlite3_create_function16()] routines that originally 4938** registered the application defined function. 4939** 4940** This routine must be called from the same thread in which 4941** the application-defined function is running. 4942*/ 4943void *sqlite3_user_data(sqlite3_context*); 4944 4945/* 4946** CAPI3REF: Database Connection For Functions 4947** METHOD: sqlite3_context 4948** 4949** ^The sqlite3_context_db_handle() interface returns a copy of 4950** the pointer to the [database connection] (the 1st parameter) 4951** of the [sqlite3_create_function()] 4952** and [sqlite3_create_function16()] routines that originally 4953** registered the application defined function. 4954*/ 4955sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4956 4957/* 4958** CAPI3REF: Function Auxiliary Data 4959** METHOD: sqlite3_context 4960** 4961** These functions may be used by (non-aggregate) SQL functions to 4962** associate metadata with argument values. If the same value is passed to 4963** multiple invocations of the same SQL function during query execution, under 4964** some circumstances the associated metadata may be preserved. An example 4965** of where this might be useful is in a regular-expression matching 4966** function. The compiled version of the regular expression can be stored as 4967** metadata associated with the pattern string. 4968** Then as long as the pattern string remains the same, 4969** the compiled regular expression can be reused on multiple 4970** invocations of the same function. 4971** 4972** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 4973** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 4974** value to the application-defined function. ^N is zero for the left-most 4975** function argument. ^If there is no metadata 4976** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 4977** returns a NULL pointer. 4978** 4979** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4980** argument of the application-defined function. ^Subsequent 4981** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4982** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4983** NULL if the metadata has been discarded. 4984** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4985** SQLite will invoke the destructor function X with parameter P exactly 4986** once, when the metadata is discarded. 4987** SQLite is free to discard the metadata at any time, including: <ul> 4988** <li> ^(when the corresponding function parameter changes)^, or 4989** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4990** SQL statement)^, or 4991** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 4992** parameter)^, or 4993** <li> ^(during the original sqlite3_set_auxdata() call when a memory 4994** allocation error occurs.)^ </ul> 4995** 4996** Note the last bullet in particular. The destructor X in 4997** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 4998** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 4999** should be called near the end of the function implementation and the 5000** function implementation should not make any use of P after 5001** sqlite3_set_auxdata() has been called. 5002** 5003** ^(In practice, metadata is preserved between function calls for 5004** function parameters that are compile-time constants, including literal 5005** values and [parameters] and expressions composed from the same.)^ 5006** 5007** The value of the N parameter to these interfaces should be non-negative. 5008** Future enhancements may make use of negative N values to define new 5009** kinds of function caching behavior. 5010** 5011** These routines must be called from the same thread in which 5012** the SQL function is running. 5013*/ 5014void *sqlite3_get_auxdata(sqlite3_context*, int N); 5015void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5016 5017 5018/* 5019** CAPI3REF: Constants Defining Special Destructor Behavior 5020** 5021** These are special values for the destructor that is passed in as the 5022** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5023** argument is SQLITE_STATIC, it means that the content pointer is constant 5024** and will never change. It does not need to be destroyed. ^The 5025** SQLITE_TRANSIENT value means that the content will likely change in 5026** the near future and that SQLite should make its own private copy of 5027** the content before returning. 5028** 5029** The typedef is necessary to work around problems in certain 5030** C++ compilers. 5031*/ 5032typedef void (*sqlite3_destructor_type)(void*); 5033#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5034#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5035 5036/* 5037** CAPI3REF: Setting The Result Of An SQL Function 5038** METHOD: sqlite3_context 5039** 5040** These routines are used by the xFunc or xFinal callbacks that 5041** implement SQL functions and aggregates. See 5042** [sqlite3_create_function()] and [sqlite3_create_function16()] 5043** for additional information. 5044** 5045** These functions work very much like the [parameter binding] family of 5046** functions used to bind values to host parameters in prepared statements. 5047** Refer to the [SQL parameter] documentation for additional information. 5048** 5049** ^The sqlite3_result_blob() interface sets the result from 5050** an application-defined function to be the BLOB whose content is pointed 5051** to by the second parameter and which is N bytes long where N is the 5052** third parameter. 5053** 5054** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5055** interfaces set the result of the application-defined function to be 5056** a BLOB containing all zero bytes and N bytes in size. 5057** 5058** ^The sqlite3_result_double() interface sets the result from 5059** an application-defined function to be a floating point value specified 5060** by its 2nd argument. 5061** 5062** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5063** cause the implemented SQL function to throw an exception. 5064** ^SQLite uses the string pointed to by the 5065** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5066** as the text of an error message. ^SQLite interprets the error 5067** message string from sqlite3_result_error() as UTF-8. ^SQLite 5068** interprets the string from sqlite3_result_error16() as UTF-16 in native 5069** byte order. ^If the third parameter to sqlite3_result_error() 5070** or sqlite3_result_error16() is negative then SQLite takes as the error 5071** message all text up through the first zero character. 5072** ^If the third parameter to sqlite3_result_error() or 5073** sqlite3_result_error16() is non-negative then SQLite takes that many 5074** bytes (not characters) from the 2nd parameter as the error message. 5075** ^The sqlite3_result_error() and sqlite3_result_error16() 5076** routines make a private copy of the error message text before 5077** they return. Hence, the calling function can deallocate or 5078** modify the text after they return without harm. 5079** ^The sqlite3_result_error_code() function changes the error code 5080** returned by SQLite as a result of an error in a function. ^By default, 5081** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5082** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5083** 5084** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5085** error indicating that a string or BLOB is too long to represent. 5086** 5087** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5088** error indicating that a memory allocation failed. 5089** 5090** ^The sqlite3_result_int() interface sets the return value 5091** of the application-defined function to be the 32-bit signed integer 5092** value given in the 2nd argument. 5093** ^The sqlite3_result_int64() interface sets the return value 5094** of the application-defined function to be the 64-bit signed integer 5095** value given in the 2nd argument. 5096** 5097** ^The sqlite3_result_null() interface sets the return value 5098** of the application-defined function to be NULL. 5099** 5100** ^The sqlite3_result_text(), sqlite3_result_text16(), 5101** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5102** set the return value of the application-defined function to be 5103** a text string which is represented as UTF-8, UTF-16 native byte order, 5104** UTF-16 little endian, or UTF-16 big endian, respectively. 5105** ^The sqlite3_result_text64() interface sets the return value of an 5106** application-defined function to be a text string in an encoding 5107** specified by the fifth (and last) parameter, which must be one 5108** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5109** ^SQLite takes the text result from the application from 5110** the 2nd parameter of the sqlite3_result_text* interfaces. 5111** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5112** is negative, then SQLite takes result text from the 2nd parameter 5113** through the first zero character. 5114** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5115** is non-negative, then as many bytes (not characters) of the text 5116** pointed to by the 2nd parameter are taken as the application-defined 5117** function result. If the 3rd parameter is non-negative, then it 5118** must be the byte offset into the string where the NUL terminator would 5119** appear if the string where NUL terminated. If any NUL characters occur 5120** in the string at a byte offset that is less than the value of the 3rd 5121** parameter, then the resulting string will contain embedded NULs and the 5122** result of expressions operating on strings with embedded NULs is undefined. 5123** ^If the 4th parameter to the sqlite3_result_text* interfaces 5124** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5125** function as the destructor on the text or BLOB result when it has 5126** finished using that result. 5127** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5128** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5129** assumes that the text or BLOB result is in constant space and does not 5130** copy the content of the parameter nor call a destructor on the content 5131** when it has finished using that result. 5132** ^If the 4th parameter to the sqlite3_result_text* interfaces 5133** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5134** then SQLite makes a copy of the result into space obtained 5135** from [sqlite3_malloc()] before it returns. 5136** 5137** ^The sqlite3_result_value() interface sets the result of 5138** the application-defined function to be a copy of the 5139** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5140** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5141** so that the [sqlite3_value] specified in the parameter may change or 5142** be deallocated after sqlite3_result_value() returns without harm. 5143** ^A [protected sqlite3_value] object may always be used where an 5144** [unprotected sqlite3_value] object is required, so either 5145** kind of [sqlite3_value] object can be used with this interface. 5146** 5147** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5148** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5149** also associates the host-language pointer P or type T with that 5150** NULL value such that the pointer can be retrieved within an 5151** [application-defined SQL function] using [sqlite3_value_pointer()]. 5152** ^If the D parameter is not NULL, then it is a pointer to a destructor 5153** for the P parameter. ^SQLite invokes D with P as its only argument 5154** when SQLite is finished with P. The T parameter should be a static 5155** string and preferably a string literal. The sqlite3_result_pointer() 5156** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5157** 5158** If these routines are called from within the different thread 5159** than the one containing the application-defined function that received 5160** the [sqlite3_context] pointer, the results are undefined. 5161*/ 5162void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5163void sqlite3_result_blob64(sqlite3_context*,const void*, 5164 sqlite3_uint64,void(*)(void*)); 5165void sqlite3_result_double(sqlite3_context*, double); 5166void sqlite3_result_error(sqlite3_context*, const char*, int); 5167void sqlite3_result_error16(sqlite3_context*, const void*, int); 5168void sqlite3_result_error_toobig(sqlite3_context*); 5169void sqlite3_result_error_nomem(sqlite3_context*); 5170void sqlite3_result_error_code(sqlite3_context*, int); 5171void sqlite3_result_int(sqlite3_context*, int); 5172void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5173void sqlite3_result_null(sqlite3_context*); 5174void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5175void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5176 void(*)(void*), unsigned char encoding); 5177void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5178void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5179void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5180void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5181void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5182void sqlite3_result_zeroblob(sqlite3_context*, int n); 5183int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5184 5185 5186/* 5187** CAPI3REF: Setting The Subtype Of An SQL Function 5188** METHOD: sqlite3_context 5189** 5190** The sqlite3_result_subtype(C,T) function causes the subtype of 5191** the result from the [application-defined SQL function] with 5192** [sqlite3_context] C to be the value T. Only the lower 8 bits 5193** of the subtype T are preserved in current versions of SQLite; 5194** higher order bits are discarded. 5195** The number of subtype bytes preserved by SQLite might increase 5196** in future releases of SQLite. 5197*/ 5198void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5199 5200/* 5201** CAPI3REF: Define New Collating Sequences 5202** METHOD: sqlite3 5203** 5204** ^These functions add, remove, or modify a [collation] associated 5205** with the [database connection] specified as the first argument. 5206** 5207** ^The name of the collation is a UTF-8 string 5208** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5209** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5210** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5211** considered to be the same name. 5212** 5213** ^(The third argument (eTextRep) must be one of the constants: 5214** <ul> 5215** <li> [SQLITE_UTF8], 5216** <li> [SQLITE_UTF16LE], 5217** <li> [SQLITE_UTF16BE], 5218** <li> [SQLITE_UTF16], or 5219** <li> [SQLITE_UTF16_ALIGNED]. 5220** </ul>)^ 5221** ^The eTextRep argument determines the encoding of strings passed 5222** to the collating function callback, xCallback. 5223** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5224** force strings to be UTF16 with native byte order. 5225** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5226** on an even byte address. 5227** 5228** ^The fourth argument, pArg, is an application data pointer that is passed 5229** through as the first argument to the collating function callback. 5230** 5231** ^The fifth argument, xCallback, is a pointer to the collating function. 5232** ^Multiple collating functions can be registered using the same name but 5233** with different eTextRep parameters and SQLite will use whichever 5234** function requires the least amount of data transformation. 5235** ^If the xCallback argument is NULL then the collating function is 5236** deleted. ^When all collating functions having the same name are deleted, 5237** that collation is no longer usable. 5238** 5239** ^The collating function callback is invoked with a copy of the pArg 5240** application data pointer and with two strings in the encoding specified 5241** by the eTextRep argument. The collating function must return an 5242** integer that is negative, zero, or positive 5243** if the first string is less than, equal to, or greater than the second, 5244** respectively. A collating function must always return the same answer 5245** given the same inputs. If two or more collating functions are registered 5246** to the same collation name (using different eTextRep values) then all 5247** must give an equivalent answer when invoked with equivalent strings. 5248** The collating function must obey the following properties for all 5249** strings A, B, and C: 5250** 5251** <ol> 5252** <li> If A==B then B==A. 5253** <li> If A==B and B==C then A==C. 5254** <li> If A<B THEN B>A. 5255** <li> If A<B and B<C then A<C. 5256** </ol> 5257** 5258** If a collating function fails any of the above constraints and that 5259** collating function is registered and used, then the behavior of SQLite 5260** is undefined. 5261** 5262** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5263** with the addition that the xDestroy callback is invoked on pArg when 5264** the collating function is deleted. 5265** ^Collating functions are deleted when they are overridden by later 5266** calls to the collation creation functions or when the 5267** [database connection] is closed using [sqlite3_close()]. 5268** 5269** ^The xDestroy callback is <u>not</u> called if the 5270** sqlite3_create_collation_v2() function fails. Applications that invoke 5271** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5272** check the return code and dispose of the application data pointer 5273** themselves rather than expecting SQLite to deal with it for them. 5274** This is different from every other SQLite interface. The inconsistency 5275** is unfortunate but cannot be changed without breaking backwards 5276** compatibility. 5277** 5278** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5279*/ 5280int sqlite3_create_collation( 5281 sqlite3*, 5282 const char *zName, 5283 int eTextRep, 5284 void *pArg, 5285 int(*xCompare)(void*,int,const void*,int,const void*) 5286); 5287int sqlite3_create_collation_v2( 5288 sqlite3*, 5289 const char *zName, 5290 int eTextRep, 5291 void *pArg, 5292 int(*xCompare)(void*,int,const void*,int,const void*), 5293 void(*xDestroy)(void*) 5294); 5295int sqlite3_create_collation16( 5296 sqlite3*, 5297 const void *zName, 5298 int eTextRep, 5299 void *pArg, 5300 int(*xCompare)(void*,int,const void*,int,const void*) 5301); 5302 5303/* 5304** CAPI3REF: Collation Needed Callbacks 5305** METHOD: sqlite3 5306** 5307** ^To avoid having to register all collation sequences before a database 5308** can be used, a single callback function may be registered with the 5309** [database connection] to be invoked whenever an undefined collation 5310** sequence is required. 5311** 5312** ^If the function is registered using the sqlite3_collation_needed() API, 5313** then it is passed the names of undefined collation sequences as strings 5314** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5315** the names are passed as UTF-16 in machine native byte order. 5316** ^A call to either function replaces the existing collation-needed callback. 5317** 5318** ^(When the callback is invoked, the first argument passed is a copy 5319** of the second argument to sqlite3_collation_needed() or 5320** sqlite3_collation_needed16(). The second argument is the database 5321** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5322** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5323** sequence function required. The fourth parameter is the name of the 5324** required collation sequence.)^ 5325** 5326** The callback function should register the desired collation using 5327** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5328** [sqlite3_create_collation_v2()]. 5329*/ 5330int sqlite3_collation_needed( 5331 sqlite3*, 5332 void*, 5333 void(*)(void*,sqlite3*,int eTextRep,const char*) 5334); 5335int sqlite3_collation_needed16( 5336 sqlite3*, 5337 void*, 5338 void(*)(void*,sqlite3*,int eTextRep,const void*) 5339); 5340 5341#ifdef SQLITE_HAS_CODEC 5342/* 5343** Specify the key for an encrypted database. This routine should be 5344** called right after sqlite3_open(). 5345** 5346** The code to implement this API is not available in the public release 5347** of SQLite. 5348*/ 5349int sqlite3_key( 5350 sqlite3 *db, /* Database to be rekeyed */ 5351 const void *pKey, int nKey /* The key */ 5352); 5353int sqlite3_key_v2( 5354 sqlite3 *db, /* Database to be rekeyed */ 5355 const char *zDbName, /* Name of the database */ 5356 const void *pKey, int nKey /* The key */ 5357); 5358 5359/* 5360** Change the key on an open database. If the current database is not 5361** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 5362** database is decrypted. 5363** 5364** The code to implement this API is not available in the public release 5365** of SQLite. 5366*/ 5367int sqlite3_rekey( 5368 sqlite3 *db, /* Database to be rekeyed */ 5369 const void *pKey, int nKey /* The new key */ 5370); 5371int sqlite3_rekey_v2( 5372 sqlite3 *db, /* Database to be rekeyed */ 5373 const char *zDbName, /* Name of the database */ 5374 const void *pKey, int nKey /* The new key */ 5375); 5376 5377/* 5378** Specify the activation key for a SEE database. Unless 5379** activated, none of the SEE routines will work. 5380*/ 5381void sqlite3_activate_see( 5382 const char *zPassPhrase /* Activation phrase */ 5383); 5384#endif 5385 5386#ifdef SQLITE_ENABLE_CEROD 5387/* 5388** Specify the activation key for a CEROD database. Unless 5389** activated, none of the CEROD routines will work. 5390*/ 5391void sqlite3_activate_cerod( 5392 const char *zPassPhrase /* Activation phrase */ 5393); 5394#endif 5395 5396/* 5397** CAPI3REF: Suspend Execution For A Short Time 5398** 5399** The sqlite3_sleep() function causes the current thread to suspend execution 5400** for at least a number of milliseconds specified in its parameter. 5401** 5402** If the operating system does not support sleep requests with 5403** millisecond time resolution, then the time will be rounded up to 5404** the nearest second. The number of milliseconds of sleep actually 5405** requested from the operating system is returned. 5406** 5407** ^SQLite implements this interface by calling the xSleep() 5408** method of the default [sqlite3_vfs] object. If the xSleep() method 5409** of the default VFS is not implemented correctly, or not implemented at 5410** all, then the behavior of sqlite3_sleep() may deviate from the description 5411** in the previous paragraphs. 5412*/ 5413int sqlite3_sleep(int); 5414 5415/* 5416** CAPI3REF: Name Of The Folder Holding Temporary Files 5417** 5418** ^(If this global variable is made to point to a string which is 5419** the name of a folder (a.k.a. directory), then all temporary files 5420** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5421** will be placed in that directory.)^ ^If this variable 5422** is a NULL pointer, then SQLite performs a search for an appropriate 5423** temporary file directory. 5424** 5425** Applications are strongly discouraged from using this global variable. 5426** It is required to set a temporary folder on Windows Runtime (WinRT). 5427** But for all other platforms, it is highly recommended that applications 5428** neither read nor write this variable. This global variable is a relic 5429** that exists for backwards compatibility of legacy applications and should 5430** be avoided in new projects. 5431** 5432** It is not safe to read or modify this variable in more than one 5433** thread at a time. It is not safe to read or modify this variable 5434** if a [database connection] is being used at the same time in a separate 5435** thread. 5436** It is intended that this variable be set once 5437** as part of process initialization and before any SQLite interface 5438** routines have been called and that this variable remain unchanged 5439** thereafter. 5440** 5441** ^The [temp_store_directory pragma] may modify this variable and cause 5442** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5443** the [temp_store_directory pragma] always assumes that any string 5444** that this variable points to is held in memory obtained from 5445** [sqlite3_malloc] and the pragma may attempt to free that memory 5446** using [sqlite3_free]. 5447** Hence, if this variable is modified directly, either it should be 5448** made NULL or made to point to memory obtained from [sqlite3_malloc] 5449** or else the use of the [temp_store_directory pragma] should be avoided. 5450** Except when requested by the [temp_store_directory pragma], SQLite 5451** does not free the memory that sqlite3_temp_directory points to. If 5452** the application wants that memory to be freed, it must do 5453** so itself, taking care to only do so after all [database connection] 5454** objects have been destroyed. 5455** 5456** <b>Note to Windows Runtime users:</b> The temporary directory must be set 5457** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 5458** features that require the use of temporary files may fail. Here is an 5459** example of how to do this using C++ with the Windows Runtime: 5460** 5461** <blockquote><pre> 5462** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 5463** TemporaryFolder->Path->Data(); 5464** char zPathBuf[MAX_PATH + 1]; 5465** memset(zPathBuf, 0, sizeof(zPathBuf)); 5466** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 5467** NULL, NULL); 5468** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 5469** </pre></blockquote> 5470*/ 5471SQLITE_EXTERN char *sqlite3_temp_directory; 5472 5473/* 5474** CAPI3REF: Name Of The Folder Holding Database Files 5475** 5476** ^(If this global variable is made to point to a string which is 5477** the name of a folder (a.k.a. directory), then all database files 5478** specified with a relative pathname and created or accessed by 5479** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 5480** to be relative to that directory.)^ ^If this variable is a NULL 5481** pointer, then SQLite assumes that all database files specified 5482** with a relative pathname are relative to the current directory 5483** for the process. Only the windows VFS makes use of this global 5484** variable; it is ignored by the unix VFS. 5485** 5486** Changing the value of this variable while a database connection is 5487** open can result in a corrupt database. 5488** 5489** It is not safe to read or modify this variable in more than one 5490** thread at a time. It is not safe to read or modify this variable 5491** if a [database connection] is being used at the same time in a separate 5492** thread. 5493** It is intended that this variable be set once 5494** as part of process initialization and before any SQLite interface 5495** routines have been called and that this variable remain unchanged 5496** thereafter. 5497** 5498** ^The [data_store_directory pragma] may modify this variable and cause 5499** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5500** the [data_store_directory pragma] always assumes that any string 5501** that this variable points to is held in memory obtained from 5502** [sqlite3_malloc] and the pragma may attempt to free that memory 5503** using [sqlite3_free]. 5504** Hence, if this variable is modified directly, either it should be 5505** made NULL or made to point to memory obtained from [sqlite3_malloc] 5506** or else the use of the [data_store_directory pragma] should be avoided. 5507*/ 5508SQLITE_EXTERN char *sqlite3_data_directory; 5509 5510/* 5511** CAPI3REF: Test For Auto-Commit Mode 5512** KEYWORDS: {autocommit mode} 5513** METHOD: sqlite3 5514** 5515** ^The sqlite3_get_autocommit() interface returns non-zero or 5516** zero if the given database connection is or is not in autocommit mode, 5517** respectively. ^Autocommit mode is on by default. 5518** ^Autocommit mode is disabled by a [BEGIN] statement. 5519** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5520** 5521** If certain kinds of errors occur on a statement within a multi-statement 5522** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5523** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5524** transaction might be rolled back automatically. The only way to 5525** find out whether SQLite automatically rolled back the transaction after 5526** an error is to use this function. 5527** 5528** If another thread changes the autocommit status of the database 5529** connection while this routine is running, then the return value 5530** is undefined. 5531*/ 5532int sqlite3_get_autocommit(sqlite3*); 5533 5534/* 5535** CAPI3REF: Find The Database Handle Of A Prepared Statement 5536** METHOD: sqlite3_stmt 5537** 5538** ^The sqlite3_db_handle interface returns the [database connection] handle 5539** to which a [prepared statement] belongs. ^The [database connection] 5540** returned by sqlite3_db_handle is the same [database connection] 5541** that was the first argument 5542** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5543** create the statement in the first place. 5544*/ 5545sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5546 5547/* 5548** CAPI3REF: Return The Filename For A Database Connection 5549** METHOD: sqlite3 5550** 5551** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5552** associated with database N of connection D. ^The main database file 5553** has the name "main". If there is no attached database N on the database 5554** connection D, or if database N is a temporary or in-memory database, then 5555** a NULL pointer is returned. 5556** 5557** ^The filename returned by this function is the output of the 5558** xFullPathname method of the [VFS]. ^In other words, the filename 5559** will be an absolute pathname, even if the filename used 5560** to open the database originally was a URI or relative pathname. 5561*/ 5562const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5563 5564/* 5565** CAPI3REF: Determine if a database is read-only 5566** METHOD: sqlite3 5567** 5568** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5569** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5570** the name of a database on connection D. 5571*/ 5572int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5573 5574/* 5575** CAPI3REF: Find the next prepared statement 5576** METHOD: sqlite3 5577** 5578** ^This interface returns a pointer to the next [prepared statement] after 5579** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5580** then this interface returns a pointer to the first prepared statement 5581** associated with the database connection pDb. ^If no prepared statement 5582** satisfies the conditions of this routine, it returns NULL. 5583** 5584** The [database connection] pointer D in a call to 5585** [sqlite3_next_stmt(D,S)] must refer to an open database 5586** connection and in particular must not be a NULL pointer. 5587*/ 5588sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5589 5590/* 5591** CAPI3REF: Commit And Rollback Notification Callbacks 5592** METHOD: sqlite3 5593** 5594** ^The sqlite3_commit_hook() interface registers a callback 5595** function to be invoked whenever a transaction is [COMMIT | committed]. 5596** ^Any callback set by a previous call to sqlite3_commit_hook() 5597** for the same database connection is overridden. 5598** ^The sqlite3_rollback_hook() interface registers a callback 5599** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5600** ^Any callback set by a previous call to sqlite3_rollback_hook() 5601** for the same database connection is overridden. 5602** ^The pArg argument is passed through to the callback. 5603** ^If the callback on a commit hook function returns non-zero, 5604** then the commit is converted into a rollback. 5605** 5606** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5607** return the P argument from the previous call of the same function 5608** on the same [database connection] D, or NULL for 5609** the first call for each function on D. 5610** 5611** The commit and rollback hook callbacks are not reentrant. 5612** The callback implementation must not do anything that will modify 5613** the database connection that invoked the callback. Any actions 5614** to modify the database connection must be deferred until after the 5615** completion of the [sqlite3_step()] call that triggered the commit 5616** or rollback hook in the first place. 5617** Note that running any other SQL statements, including SELECT statements, 5618** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5619** the database connections for the meaning of "modify" in this paragraph. 5620** 5621** ^Registering a NULL function disables the callback. 5622** 5623** ^When the commit hook callback routine returns zero, the [COMMIT] 5624** operation is allowed to continue normally. ^If the commit hook 5625** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5626** ^The rollback hook is invoked on a rollback that results from a commit 5627** hook returning non-zero, just as it would be with any other rollback. 5628** 5629** ^For the purposes of this API, a transaction is said to have been 5630** rolled back if an explicit "ROLLBACK" statement is executed, or 5631** an error or constraint causes an implicit rollback to occur. 5632** ^The rollback callback is not invoked if a transaction is 5633** automatically rolled back because the database connection is closed. 5634** 5635** See also the [sqlite3_update_hook()] interface. 5636*/ 5637void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5638void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5639 5640/* 5641** CAPI3REF: Data Change Notification Callbacks 5642** METHOD: sqlite3 5643** 5644** ^The sqlite3_update_hook() interface registers a callback function 5645** with the [database connection] identified by the first argument 5646** to be invoked whenever a row is updated, inserted or deleted in 5647** a [rowid table]. 5648** ^Any callback set by a previous call to this function 5649** for the same database connection is overridden. 5650** 5651** ^The second argument is a pointer to the function to invoke when a 5652** row is updated, inserted or deleted in a rowid table. 5653** ^The first argument to the callback is a copy of the third argument 5654** to sqlite3_update_hook(). 5655** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5656** or [SQLITE_UPDATE], depending on the operation that caused the callback 5657** to be invoked. 5658** ^The third and fourth arguments to the callback contain pointers to the 5659** database and table name containing the affected row. 5660** ^The final callback parameter is the [rowid] of the row. 5661** ^In the case of an update, this is the [rowid] after the update takes place. 5662** 5663** ^(The update hook is not invoked when internal system tables are 5664** modified (i.e. sqlite_master and sqlite_sequence).)^ 5665** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5666** 5667** ^In the current implementation, the update hook 5668** is not invoked when conflicting rows are deleted because of an 5669** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5670** invoked when rows are deleted using the [truncate optimization]. 5671** The exceptions defined in this paragraph might change in a future 5672** release of SQLite. 5673** 5674** The update hook implementation must not do anything that will modify 5675** the database connection that invoked the update hook. Any actions 5676** to modify the database connection must be deferred until after the 5677** completion of the [sqlite3_step()] call that triggered the update hook. 5678** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5679** database connections for the meaning of "modify" in this paragraph. 5680** 5681** ^The sqlite3_update_hook(D,C,P) function 5682** returns the P argument from the previous call 5683** on the same [database connection] D, or NULL for 5684** the first call on D. 5685** 5686** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 5687** and [sqlite3_preupdate_hook()] interfaces. 5688*/ 5689void *sqlite3_update_hook( 5690 sqlite3*, 5691 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5692 void* 5693); 5694 5695/* 5696** CAPI3REF: Enable Or Disable Shared Pager Cache 5697** 5698** ^(This routine enables or disables the sharing of the database cache 5699** and schema data structures between [database connection | connections] 5700** to the same database. Sharing is enabled if the argument is true 5701** and disabled if the argument is false.)^ 5702** 5703** ^Cache sharing is enabled and disabled for an entire process. 5704** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 5705** In prior versions of SQLite, 5706** sharing was enabled or disabled for each thread separately. 5707** 5708** ^(The cache sharing mode set by this interface effects all subsequent 5709** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5710** Existing database connections continue use the sharing mode 5711** that was in effect at the time they were opened.)^ 5712** 5713** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5714** successfully. An [error code] is returned otherwise.)^ 5715** 5716** ^Shared cache is disabled by default. But this might change in 5717** future releases of SQLite. Applications that care about shared 5718** cache setting should set it explicitly. 5719** 5720** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5721** and will always return SQLITE_MISUSE. On those systems, 5722** shared cache mode should be enabled per-database connection via 5723** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5724** 5725** This interface is threadsafe on processors where writing a 5726** 32-bit integer is atomic. 5727** 5728** See Also: [SQLite Shared-Cache Mode] 5729*/ 5730int sqlite3_enable_shared_cache(int); 5731 5732/* 5733** CAPI3REF: Attempt To Free Heap Memory 5734** 5735** ^The sqlite3_release_memory() interface attempts to free N bytes 5736** of heap memory by deallocating non-essential memory allocations 5737** held by the database library. Memory used to cache database 5738** pages to improve performance is an example of non-essential memory. 5739** ^sqlite3_release_memory() returns the number of bytes actually freed, 5740** which might be more or less than the amount requested. 5741** ^The sqlite3_release_memory() routine is a no-op returning zero 5742** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5743** 5744** See also: [sqlite3_db_release_memory()] 5745*/ 5746int sqlite3_release_memory(int); 5747 5748/* 5749** CAPI3REF: Free Memory Used By A Database Connection 5750** METHOD: sqlite3 5751** 5752** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5753** memory as possible from database connection D. Unlike the 5754** [sqlite3_release_memory()] interface, this interface is in effect even 5755** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5756** omitted. 5757** 5758** See also: [sqlite3_release_memory()] 5759*/ 5760int sqlite3_db_release_memory(sqlite3*); 5761 5762/* 5763** CAPI3REF: Impose A Limit On Heap Size 5764** 5765** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5766** soft limit on the amount of heap memory that may be allocated by SQLite. 5767** ^SQLite strives to keep heap memory utilization below the soft heap 5768** limit by reducing the number of pages held in the page cache 5769** as heap memory usages approaches the limit. 5770** ^The soft heap limit is "soft" because even though SQLite strives to stay 5771** below the limit, it will exceed the limit rather than generate 5772** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5773** is advisory only. 5774** 5775** ^The return value from sqlite3_soft_heap_limit64() is the size of 5776** the soft heap limit prior to the call, or negative in the case of an 5777** error. ^If the argument N is negative 5778** then no change is made to the soft heap limit. Hence, the current 5779** size of the soft heap limit can be determined by invoking 5780** sqlite3_soft_heap_limit64() with a negative argument. 5781** 5782** ^If the argument N is zero then the soft heap limit is disabled. 5783** 5784** ^(The soft heap limit is not enforced in the current implementation 5785** if one or more of following conditions are true: 5786** 5787** <ul> 5788** <li> The soft heap limit is set to zero. 5789** <li> Memory accounting is disabled using a combination of the 5790** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5791** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5792** <li> An alternative page cache implementation is specified using 5793** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5794** <li> The page cache allocates from its own memory pool supplied 5795** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5796** from the heap. 5797** </ul>)^ 5798** 5799** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]), 5800** the soft heap limit is enforced 5801** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5802** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5803** the soft heap limit is enforced on every memory allocation. Without 5804** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5805** when memory is allocated by the page cache. Testing suggests that because 5806** the page cache is the predominate memory user in SQLite, most 5807** applications will achieve adequate soft heap limit enforcement without 5808** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5809** 5810** The circumstances under which SQLite will enforce the soft heap limit may 5811** changes in future releases of SQLite. 5812*/ 5813sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5814 5815/* 5816** CAPI3REF: Deprecated Soft Heap Limit Interface 5817** DEPRECATED 5818** 5819** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5820** interface. This routine is provided for historical compatibility 5821** only. All new applications should use the 5822** [sqlite3_soft_heap_limit64()] interface rather than this one. 5823*/ 5824SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5825 5826 5827/* 5828** CAPI3REF: Extract Metadata About A Column Of A Table 5829** METHOD: sqlite3 5830** 5831** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5832** information about column C of table T in database D 5833** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5834** interface returns SQLITE_OK and fills in the non-NULL pointers in 5835** the final five arguments with appropriate values if the specified 5836** column exists. ^The sqlite3_table_column_metadata() interface returns 5837** SQLITE_ERROR and if the specified column does not exist. 5838** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5839** NULL pointer, then this routine simply checks for the existence of the 5840** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5841** does not. If the table name parameter T in a call to 5842** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 5843** undefined behavior. 5844** 5845** ^The column is identified by the second, third and fourth parameters to 5846** this function. ^(The second parameter is either the name of the database 5847** (i.e. "main", "temp", or an attached database) containing the specified 5848** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5849** for the table using the same algorithm used by the database engine to 5850** resolve unqualified table references. 5851** 5852** ^The third and fourth parameters to this function are the table and column 5853** name of the desired column, respectively. 5854** 5855** ^Metadata is returned by writing to the memory locations passed as the 5th 5856** and subsequent parameters to this function. ^Any of these arguments may be 5857** NULL, in which case the corresponding element of metadata is omitted. 5858** 5859** ^(<blockquote> 5860** <table border="1"> 5861** <tr><th> Parameter <th> Output<br>Type <th> Description 5862** 5863** <tr><td> 5th <td> const char* <td> Data type 5864** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5865** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5866** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5867** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5868** </table> 5869** </blockquote>)^ 5870** 5871** ^The memory pointed to by the character pointers returned for the 5872** declaration type and collation sequence is valid until the next 5873** call to any SQLite API function. 5874** 5875** ^If the specified table is actually a view, an [error code] is returned. 5876** 5877** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5878** is not a [WITHOUT ROWID] table and an 5879** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5880** parameters are set for the explicitly declared column. ^(If there is no 5881** [INTEGER PRIMARY KEY] column, then the outputs 5882** for the [rowid] are set as follows: 5883** 5884** <pre> 5885** data type: "INTEGER" 5886** collation sequence: "BINARY" 5887** not null: 0 5888** primary key: 1 5889** auto increment: 0 5890** </pre>)^ 5891** 5892** ^This function causes all database schemas to be read from disk and 5893** parsed, if that has not already been done, and returns an error if 5894** any errors are encountered while loading the schema. 5895*/ 5896int sqlite3_table_column_metadata( 5897 sqlite3 *db, /* Connection handle */ 5898 const char *zDbName, /* Database name or NULL */ 5899 const char *zTableName, /* Table name */ 5900 const char *zColumnName, /* Column name */ 5901 char const **pzDataType, /* OUTPUT: Declared data type */ 5902 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5903 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5904 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5905 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5906); 5907 5908/* 5909** CAPI3REF: Load An Extension 5910** METHOD: sqlite3 5911** 5912** ^This interface loads an SQLite extension library from the named file. 5913** 5914** ^The sqlite3_load_extension() interface attempts to load an 5915** [SQLite extension] library contained in the file zFile. If 5916** the file cannot be loaded directly, attempts are made to load 5917** with various operating-system specific extensions added. 5918** So for example, if "samplelib" cannot be loaded, then names like 5919** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5920** be tried also. 5921** 5922** ^The entry point is zProc. 5923** ^(zProc may be 0, in which case SQLite will try to come up with an 5924** entry point name on its own. It first tries "sqlite3_extension_init". 5925** If that does not work, it constructs a name "sqlite3_X_init" where the 5926** X is consists of the lower-case equivalent of all ASCII alphabetic 5927** characters in the filename from the last "/" to the first following 5928** "." and omitting any initial "lib".)^ 5929** ^The sqlite3_load_extension() interface returns 5930** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5931** ^If an error occurs and pzErrMsg is not 0, then the 5932** [sqlite3_load_extension()] interface shall attempt to 5933** fill *pzErrMsg with error message text stored in memory 5934** obtained from [sqlite3_malloc()]. The calling function 5935** should free this memory by calling [sqlite3_free()]. 5936** 5937** ^Extension loading must be enabled using 5938** [sqlite3_enable_load_extension()] or 5939** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 5940** prior to calling this API, 5941** otherwise an error will be returned. 5942** 5943** <b>Security warning:</b> It is recommended that the 5944** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 5945** interface. The use of the [sqlite3_enable_load_extension()] interface 5946** should be avoided. This will keep the SQL function [load_extension()] 5947** disabled and prevent SQL injections from giving attackers 5948** access to extension loading capabilities. 5949** 5950** See also the [load_extension() SQL function]. 5951*/ 5952int sqlite3_load_extension( 5953 sqlite3 *db, /* Load the extension into this database connection */ 5954 const char *zFile, /* Name of the shared library containing extension */ 5955 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5956 char **pzErrMsg /* Put error message here if not 0 */ 5957); 5958 5959/* 5960** CAPI3REF: Enable Or Disable Extension Loading 5961** METHOD: sqlite3 5962** 5963** ^So as not to open security holes in older applications that are 5964** unprepared to deal with [extension loading], and as a means of disabling 5965** [extension loading] while evaluating user-entered SQL, the following API 5966** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5967** 5968** ^Extension loading is off by default. 5969** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5970** to turn extension loading on and call it with onoff==0 to turn 5971** it back off again. 5972** 5973** ^This interface enables or disables both the C-API 5974** [sqlite3_load_extension()] and the SQL function [load_extension()]. 5975** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 5976** to enable or disable only the C-API.)^ 5977** 5978** <b>Security warning:</b> It is recommended that extension loading 5979** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 5980** rather than this interface, so the [load_extension()] SQL function 5981** remains disabled. This will prevent SQL injections from giving attackers 5982** access to extension loading capabilities. 5983*/ 5984int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5985 5986/* 5987** CAPI3REF: Automatically Load Statically Linked Extensions 5988** 5989** ^This interface causes the xEntryPoint() function to be invoked for 5990** each new [database connection] that is created. The idea here is that 5991** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5992** that is to be automatically loaded into all new database connections. 5993** 5994** ^(Even though the function prototype shows that xEntryPoint() takes 5995** no arguments and returns void, SQLite invokes xEntryPoint() with three 5996** arguments and expects an integer result as if the signature of the 5997** entry point where as follows: 5998** 5999** <blockquote><pre> 6000** int xEntryPoint( 6001** sqlite3 *db, 6002** const char **pzErrMsg, 6003** const struct sqlite3_api_routines *pThunk 6004** ); 6005** </pre></blockquote>)^ 6006** 6007** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 6008** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 6009** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 6010** is NULL before calling the xEntryPoint(). ^SQLite will invoke 6011** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 6012** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 6013** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6014** 6015** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6016** on the list of automatic extensions is a harmless no-op. ^No entry point 6017** will be called more than once for each database connection that is opened. 6018** 6019** See also: [sqlite3_reset_auto_extension()] 6020** and [sqlite3_cancel_auto_extension()] 6021*/ 6022int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6023 6024/* 6025** CAPI3REF: Cancel Automatic Extension Loading 6026** 6027** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6028** initialization routine X that was registered using a prior call to 6029** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6030** routine returns 1 if initialization routine X was successfully 6031** unregistered and it returns 0 if X was not on the list of initialization 6032** routines. 6033*/ 6034int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6035 6036/* 6037** CAPI3REF: Reset Automatic Extension Loading 6038** 6039** ^This interface disables all automatic extensions previously 6040** registered using [sqlite3_auto_extension()]. 6041*/ 6042void sqlite3_reset_auto_extension(void); 6043 6044/* 6045** The interface to the virtual-table mechanism is currently considered 6046** to be experimental. The interface might change in incompatible ways. 6047** If this is a problem for you, do not use the interface at this time. 6048** 6049** When the virtual-table mechanism stabilizes, we will declare the 6050** interface fixed, support it indefinitely, and remove this comment. 6051*/ 6052 6053/* 6054** Structures used by the virtual table interface 6055*/ 6056typedef struct sqlite3_vtab sqlite3_vtab; 6057typedef struct sqlite3_index_info sqlite3_index_info; 6058typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6059typedef struct sqlite3_module sqlite3_module; 6060 6061/* 6062** CAPI3REF: Virtual Table Object 6063** KEYWORDS: sqlite3_module {virtual table module} 6064** 6065** This structure, sometimes called a "virtual table module", 6066** defines the implementation of a [virtual tables]. 6067** This structure consists mostly of methods for the module. 6068** 6069** ^A virtual table module is created by filling in a persistent 6070** instance of this structure and passing a pointer to that instance 6071** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6072** ^The registration remains valid until it is replaced by a different 6073** module or until the [database connection] closes. The content 6074** of this structure must not change while it is registered with 6075** any database connection. 6076*/ 6077struct sqlite3_module { 6078 int iVersion; 6079 int (*xCreate)(sqlite3*, void *pAux, 6080 int argc, const char *const*argv, 6081 sqlite3_vtab **ppVTab, char**); 6082 int (*xConnect)(sqlite3*, void *pAux, 6083 int argc, const char *const*argv, 6084 sqlite3_vtab **ppVTab, char**); 6085 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6086 int (*xDisconnect)(sqlite3_vtab *pVTab); 6087 int (*xDestroy)(sqlite3_vtab *pVTab); 6088 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6089 int (*xClose)(sqlite3_vtab_cursor*); 6090 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6091 int argc, sqlite3_value **argv); 6092 int (*xNext)(sqlite3_vtab_cursor*); 6093 int (*xEof)(sqlite3_vtab_cursor*); 6094 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6095 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6096 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6097 int (*xBegin)(sqlite3_vtab *pVTab); 6098 int (*xSync)(sqlite3_vtab *pVTab); 6099 int (*xCommit)(sqlite3_vtab *pVTab); 6100 int (*xRollback)(sqlite3_vtab *pVTab); 6101 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6102 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6103 void **ppArg); 6104 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6105 /* The methods above are in version 1 of the sqlite_module object. Those 6106 ** below are for version 2 and greater. */ 6107 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6108 int (*xRelease)(sqlite3_vtab *pVTab, int); 6109 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6110}; 6111 6112/* 6113** CAPI3REF: Virtual Table Indexing Information 6114** KEYWORDS: sqlite3_index_info 6115** 6116** The sqlite3_index_info structure and its substructures is used as part 6117** of the [virtual table] interface to 6118** pass information into and receive the reply from the [xBestIndex] 6119** method of a [virtual table module]. The fields under **Inputs** are the 6120** inputs to xBestIndex and are read-only. xBestIndex inserts its 6121** results into the **Outputs** fields. 6122** 6123** ^(The aConstraint[] array records WHERE clause constraints of the form: 6124** 6125** <blockquote>column OP expr</blockquote> 6126** 6127** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6128** stored in aConstraint[].op using one of the 6129** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6130** ^(The index of the column is stored in 6131** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6132** expr on the right-hand side can be evaluated (and thus the constraint 6133** is usable) and false if it cannot.)^ 6134** 6135** ^The optimizer automatically inverts terms of the form "expr OP column" 6136** and makes other simplifications to the WHERE clause in an attempt to 6137** get as many WHERE clause terms into the form shown above as possible. 6138** ^The aConstraint[] array only reports WHERE clause terms that are 6139** relevant to the particular virtual table being queried. 6140** 6141** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6142** ^Each term of aOrderBy records a column of the ORDER BY clause. 6143** 6144** The colUsed field indicates which columns of the virtual table may be 6145** required by the current scan. Virtual table columns are numbered from 6146** zero in the order in which they appear within the CREATE TABLE statement 6147** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6148** the corresponding bit is set within the colUsed mask if the column may be 6149** required by SQLite. If the table has at least 64 columns and any column 6150** to the right of the first 63 is required, then bit 63 of colUsed is also 6151** set. In other words, column iCol may be required if the expression 6152** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6153** non-zero. 6154** 6155** The [xBestIndex] method must fill aConstraintUsage[] with information 6156** about what parameters to pass to xFilter. ^If argvIndex>0 then 6157** the right-hand side of the corresponding aConstraint[] is evaluated 6158** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6159** is true, then the constraint is assumed to be fully handled by the 6160** virtual table and is not checked again by SQLite.)^ 6161** 6162** ^The idxNum and idxPtr values are recorded and passed into the 6163** [xFilter] method. 6164** ^[sqlite3_free()] is used to free idxPtr if and only if 6165** needToFreeIdxPtr is true. 6166** 6167** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6168** the correct order to satisfy the ORDER BY clause so that no separate 6169** sorting step is required. 6170** 6171** ^The estimatedCost value is an estimate of the cost of a particular 6172** strategy. A cost of N indicates that the cost of the strategy is similar 6173** to a linear scan of an SQLite table with N rows. A cost of log(N) 6174** indicates that the expense of the operation is similar to that of a 6175** binary search on a unique indexed field of an SQLite table with N rows. 6176** 6177** ^The estimatedRows value is an estimate of the number of rows that 6178** will be returned by the strategy. 6179** 6180** The xBestIndex method may optionally populate the idxFlags field with a 6181** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6182** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6183** assumes that the strategy may visit at most one row. 6184** 6185** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6186** SQLite also assumes that if a call to the xUpdate() method is made as 6187** part of the same statement to delete or update a virtual table row and the 6188** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6189** any database changes. In other words, if the xUpdate() returns 6190** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6191** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6192** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6193** the xUpdate method are automatically rolled back by SQLite. 6194** 6195** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6196** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6197** If a virtual table extension is 6198** used with an SQLite version earlier than 3.8.2, the results of attempting 6199** to read or write the estimatedRows field are undefined (but are likely 6200** to included crashing the application). The estimatedRows field should 6201** therefore only be used if [sqlite3_libversion_number()] returns a 6202** value greater than or equal to 3008002. Similarly, the idxFlags field 6203** was added for [version 3.9.0] ([dateof:3.9.0]). 6204** It may therefore only be used if 6205** sqlite3_libversion_number() returns a value greater than or equal to 6206** 3009000. 6207*/ 6208struct sqlite3_index_info { 6209 /* Inputs */ 6210 int nConstraint; /* Number of entries in aConstraint */ 6211 struct sqlite3_index_constraint { 6212 int iColumn; /* Column constrained. -1 for ROWID */ 6213 unsigned char op; /* Constraint operator */ 6214 unsigned char usable; /* True if this constraint is usable */ 6215 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6216 } *aConstraint; /* Table of WHERE clause constraints */ 6217 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6218 struct sqlite3_index_orderby { 6219 int iColumn; /* Column number */ 6220 unsigned char desc; /* True for DESC. False for ASC. */ 6221 } *aOrderBy; /* The ORDER BY clause */ 6222 /* Outputs */ 6223 struct sqlite3_index_constraint_usage { 6224 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6225 unsigned char omit; /* Do not code a test for this constraint */ 6226 } *aConstraintUsage; 6227 int idxNum; /* Number used to identify the index */ 6228 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6229 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6230 int orderByConsumed; /* True if output is already ordered */ 6231 double estimatedCost; /* Estimated cost of using this index */ 6232 /* Fields below are only available in SQLite 3.8.2 and later */ 6233 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6234 /* Fields below are only available in SQLite 3.9.0 and later */ 6235 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6236 /* Fields below are only available in SQLite 3.10.0 and later */ 6237 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6238}; 6239 6240/* 6241** CAPI3REF: Virtual Table Scan Flags 6242*/ 6243#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6244 6245/* 6246** CAPI3REF: Virtual Table Constraint Operator Codes 6247** 6248** These macros defined the allowed values for the 6249** [sqlite3_index_info].aConstraint[].op field. Each value represents 6250** an operator that is part of a constraint term in the wHERE clause of 6251** a query that uses a [virtual table]. 6252*/ 6253#define SQLITE_INDEX_CONSTRAINT_EQ 2 6254#define SQLITE_INDEX_CONSTRAINT_GT 4 6255#define SQLITE_INDEX_CONSTRAINT_LE 8 6256#define SQLITE_INDEX_CONSTRAINT_LT 16 6257#define SQLITE_INDEX_CONSTRAINT_GE 32 6258#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6259#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6260#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6261#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6262 6263/* 6264** CAPI3REF: Register A Virtual Table Implementation 6265** METHOD: sqlite3 6266** 6267** ^These routines are used to register a new [virtual table module] name. 6268** ^Module names must be registered before 6269** creating a new [virtual table] using the module and before using a 6270** preexisting [virtual table] for the module. 6271** 6272** ^The module name is registered on the [database connection] specified 6273** by the first parameter. ^The name of the module is given by the 6274** second parameter. ^The third parameter is a pointer to 6275** the implementation of the [virtual table module]. ^The fourth 6276** parameter is an arbitrary client data pointer that is passed through 6277** into the [xCreate] and [xConnect] methods of the virtual table module 6278** when a new virtual table is be being created or reinitialized. 6279** 6280** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6281** is a pointer to a destructor for the pClientData. ^SQLite will 6282** invoke the destructor function (if it is not NULL) when SQLite 6283** no longer needs the pClientData pointer. ^The destructor will also 6284** be invoked if the call to sqlite3_create_module_v2() fails. 6285** ^The sqlite3_create_module() 6286** interface is equivalent to sqlite3_create_module_v2() with a NULL 6287** destructor. 6288*/ 6289int sqlite3_create_module( 6290 sqlite3 *db, /* SQLite connection to register module with */ 6291 const char *zName, /* Name of the module */ 6292 const sqlite3_module *p, /* Methods for the module */ 6293 void *pClientData /* Client data for xCreate/xConnect */ 6294); 6295int sqlite3_create_module_v2( 6296 sqlite3 *db, /* SQLite connection to register module with */ 6297 const char *zName, /* Name of the module */ 6298 const sqlite3_module *p, /* Methods for the module */ 6299 void *pClientData, /* Client data for xCreate/xConnect */ 6300 void(*xDestroy)(void*) /* Module destructor function */ 6301); 6302 6303/* 6304** CAPI3REF: Virtual Table Instance Object 6305** KEYWORDS: sqlite3_vtab 6306** 6307** Every [virtual table module] implementation uses a subclass 6308** of this object to describe a particular instance 6309** of the [virtual table]. Each subclass will 6310** be tailored to the specific needs of the module implementation. 6311** The purpose of this superclass is to define certain fields that are 6312** common to all module implementations. 6313** 6314** ^Virtual tables methods can set an error message by assigning a 6315** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 6316** take care that any prior string is freed by a call to [sqlite3_free()] 6317** prior to assigning a new string to zErrMsg. ^After the error message 6318** is delivered up to the client application, the string will be automatically 6319** freed by sqlite3_free() and the zErrMsg field will be zeroed. 6320*/ 6321struct sqlite3_vtab { 6322 const sqlite3_module *pModule; /* The module for this virtual table */ 6323 int nRef; /* Number of open cursors */ 6324 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 6325 /* Virtual table implementations will typically add additional fields */ 6326}; 6327 6328/* 6329** CAPI3REF: Virtual Table Cursor Object 6330** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 6331** 6332** Every [virtual table module] implementation uses a subclass of the 6333** following structure to describe cursors that point into the 6334** [virtual table] and are used 6335** to loop through the virtual table. Cursors are created using the 6336** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 6337** by the [sqlite3_module.xClose | xClose] method. Cursors are used 6338** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 6339** of the module. Each module implementation will define 6340** the content of a cursor structure to suit its own needs. 6341** 6342** This superclass exists in order to define fields of the cursor that 6343** are common to all implementations. 6344*/ 6345struct sqlite3_vtab_cursor { 6346 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 6347 /* Virtual table implementations will typically add additional fields */ 6348}; 6349 6350/* 6351** CAPI3REF: Declare The Schema Of A Virtual Table 6352** 6353** ^The [xCreate] and [xConnect] methods of a 6354** [virtual table module] call this interface 6355** to declare the format (the names and datatypes of the columns) of 6356** the virtual tables they implement. 6357*/ 6358int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 6359 6360/* 6361** CAPI3REF: Overload A Function For A Virtual Table 6362** METHOD: sqlite3 6363** 6364** ^(Virtual tables can provide alternative implementations of functions 6365** using the [xFindFunction] method of the [virtual table module]. 6366** But global versions of those functions 6367** must exist in order to be overloaded.)^ 6368** 6369** ^(This API makes sure a global version of a function with a particular 6370** name and number of parameters exists. If no such function exists 6371** before this API is called, a new function is created.)^ ^The implementation 6372** of the new function always causes an exception to be thrown. So 6373** the new function is not good for anything by itself. Its only 6374** purpose is to be a placeholder function that can be overloaded 6375** by a [virtual table]. 6376*/ 6377int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 6378 6379/* 6380** The interface to the virtual-table mechanism defined above (back up 6381** to a comment remarkably similar to this one) is currently considered 6382** to be experimental. The interface might change in incompatible ways. 6383** If this is a problem for you, do not use the interface at this time. 6384** 6385** When the virtual-table mechanism stabilizes, we will declare the 6386** interface fixed, support it indefinitely, and remove this comment. 6387*/ 6388 6389/* 6390** CAPI3REF: A Handle To An Open BLOB 6391** KEYWORDS: {BLOB handle} {BLOB handles} 6392** 6393** An instance of this object represents an open BLOB on which 6394** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 6395** ^Objects of this type are created by [sqlite3_blob_open()] 6396** and destroyed by [sqlite3_blob_close()]. 6397** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 6398** can be used to read or write small subsections of the BLOB. 6399** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 6400*/ 6401typedef struct sqlite3_blob sqlite3_blob; 6402 6403/* 6404** CAPI3REF: Open A BLOB For Incremental I/O 6405** METHOD: sqlite3 6406** CONSTRUCTOR: sqlite3_blob 6407** 6408** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 6409** in row iRow, column zColumn, table zTable in database zDb; 6410** in other words, the same BLOB that would be selected by: 6411** 6412** <pre> 6413** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 6414** </pre>)^ 6415** 6416** ^(Parameter zDb is not the filename that contains the database, but 6417** rather the symbolic name of the database. For attached databases, this is 6418** the name that appears after the AS keyword in the [ATTACH] statement. 6419** For the main database file, the database name is "main". For TEMP 6420** tables, the database name is "temp".)^ 6421** 6422** ^If the flags parameter is non-zero, then the BLOB is opened for read 6423** and write access. ^If the flags parameter is zero, the BLOB is opened for 6424** read-only access. 6425** 6426** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 6427** in *ppBlob. Otherwise an [error code] is returned and, unless the error 6428** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 6429** the API is not misused, it is always safe to call [sqlite3_blob_close()] 6430** on *ppBlob after this function it returns. 6431** 6432** This function fails with SQLITE_ERROR if any of the following are true: 6433** <ul> 6434** <li> ^(Database zDb does not exist)^, 6435** <li> ^(Table zTable does not exist within database zDb)^, 6436** <li> ^(Table zTable is a WITHOUT ROWID table)^, 6437** <li> ^(Column zColumn does not exist)^, 6438** <li> ^(Row iRow is not present in the table)^, 6439** <li> ^(The specified column of row iRow contains a value that is not 6440** a TEXT or BLOB value)^, 6441** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 6442** constraint and the blob is being opened for read/write access)^, 6443** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 6444** column zColumn is part of a [child key] definition and the blob is 6445** being opened for read/write access)^. 6446** </ul> 6447** 6448** ^Unless it returns SQLITE_MISUSE, this function sets the 6449** [database connection] error code and message accessible via 6450** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6451** 6452** A BLOB referenced by sqlite3_blob_open() may be read using the 6453** [sqlite3_blob_read()] interface and modified by using 6454** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 6455** different row of the same table using the [sqlite3_blob_reopen()] 6456** interface. However, the column, table, or database of a [BLOB handle] 6457** cannot be changed after the [BLOB handle] is opened. 6458** 6459** ^(If the row that a BLOB handle points to is modified by an 6460** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 6461** then the BLOB handle is marked as "expired". 6462** This is true if any column of the row is changed, even a column 6463** other than the one the BLOB handle is open on.)^ 6464** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 6465** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 6466** ^(Changes written into a BLOB prior to the BLOB expiring are not 6467** rolled back by the expiration of the BLOB. Such changes will eventually 6468** commit if the transaction continues to completion.)^ 6469** 6470** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 6471** the opened blob. ^The size of a blob may not be changed by this 6472** interface. Use the [UPDATE] SQL command to change the size of a 6473** blob. 6474** 6475** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 6476** and the built-in [zeroblob] SQL function may be used to create a 6477** zero-filled blob to read or write using the incremental-blob interface. 6478** 6479** To avoid a resource leak, every open [BLOB handle] should eventually 6480** be released by a call to [sqlite3_blob_close()]. 6481** 6482** See also: [sqlite3_blob_close()], 6483** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 6484** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 6485*/ 6486int sqlite3_blob_open( 6487 sqlite3*, 6488 const char *zDb, 6489 const char *zTable, 6490 const char *zColumn, 6491 sqlite3_int64 iRow, 6492 int flags, 6493 sqlite3_blob **ppBlob 6494); 6495 6496/* 6497** CAPI3REF: Move a BLOB Handle to a New Row 6498** METHOD: sqlite3_blob 6499** 6500** ^This function is used to move an existing [BLOB handle] so that it points 6501** to a different row of the same database table. ^The new row is identified 6502** by the rowid value passed as the second argument. Only the row can be 6503** changed. ^The database, table and column on which the blob handle is open 6504** remain the same. Moving an existing [BLOB handle] to a new row is 6505** faster than closing the existing handle and opening a new one. 6506** 6507** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 6508** it must exist and there must be either a blob or text value stored in 6509** the nominated column.)^ ^If the new row is not present in the table, or if 6510** it does not contain a blob or text value, or if another error occurs, an 6511** SQLite error code is returned and the blob handle is considered aborted. 6512** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 6513** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 6514** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 6515** always returns zero. 6516** 6517** ^This function sets the database handle error code and message. 6518*/ 6519int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 6520 6521/* 6522** CAPI3REF: Close A BLOB Handle 6523** DESTRUCTOR: sqlite3_blob 6524** 6525** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 6526** unconditionally. Even if this routine returns an error code, the 6527** handle is still closed.)^ 6528** 6529** ^If the blob handle being closed was opened for read-write access, and if 6530** the database is in auto-commit mode and there are no other open read-write 6531** blob handles or active write statements, the current transaction is 6532** committed. ^If an error occurs while committing the transaction, an error 6533** code is returned and the transaction rolled back. 6534** 6535** Calling this function with an argument that is not a NULL pointer or an 6536** open blob handle results in undefined behaviour. ^Calling this routine 6537** with a null pointer (such as would be returned by a failed call to 6538** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 6539** is passed a valid open blob handle, the values returned by the 6540** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 6541*/ 6542int sqlite3_blob_close(sqlite3_blob *); 6543 6544/* 6545** CAPI3REF: Return The Size Of An Open BLOB 6546** METHOD: sqlite3_blob 6547** 6548** ^Returns the size in bytes of the BLOB accessible via the 6549** successfully opened [BLOB handle] in its only argument. ^The 6550** incremental blob I/O routines can only read or overwriting existing 6551** blob content; they cannot change the size of a blob. 6552** 6553** This routine only works on a [BLOB handle] which has been created 6554** by a prior successful call to [sqlite3_blob_open()] and which has not 6555** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6556** to this routine results in undefined and probably undesirable behavior. 6557*/ 6558int sqlite3_blob_bytes(sqlite3_blob *); 6559 6560/* 6561** CAPI3REF: Read Data From A BLOB Incrementally 6562** METHOD: sqlite3_blob 6563** 6564** ^(This function is used to read data from an open [BLOB handle] into a 6565** caller-supplied buffer. N bytes of data are copied into buffer Z 6566** from the open BLOB, starting at offset iOffset.)^ 6567** 6568** ^If offset iOffset is less than N bytes from the end of the BLOB, 6569** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6570** less than zero, [SQLITE_ERROR] is returned and no data is read. 6571** ^The size of the blob (and hence the maximum value of N+iOffset) 6572** can be determined using the [sqlite3_blob_bytes()] interface. 6573** 6574** ^An attempt to read from an expired [BLOB handle] fails with an 6575** error code of [SQLITE_ABORT]. 6576** 6577** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6578** Otherwise, an [error code] or an [extended error code] is returned.)^ 6579** 6580** This routine only works on a [BLOB handle] which has been created 6581** by a prior successful call to [sqlite3_blob_open()] and which has not 6582** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6583** to this routine results in undefined and probably undesirable behavior. 6584** 6585** See also: [sqlite3_blob_write()]. 6586*/ 6587int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6588 6589/* 6590** CAPI3REF: Write Data Into A BLOB Incrementally 6591** METHOD: sqlite3_blob 6592** 6593** ^(This function is used to write data into an open [BLOB handle] from a 6594** caller-supplied buffer. N bytes of data are copied from the buffer Z 6595** into the open BLOB, starting at offset iOffset.)^ 6596** 6597** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6598** Otherwise, an [error code] or an [extended error code] is returned.)^ 6599** ^Unless SQLITE_MISUSE is returned, this function sets the 6600** [database connection] error code and message accessible via 6601** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6602** 6603** ^If the [BLOB handle] passed as the first argument was not opened for 6604** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6605** this function returns [SQLITE_READONLY]. 6606** 6607** This function may only modify the contents of the BLOB; it is 6608** not possible to increase the size of a BLOB using this API. 6609** ^If offset iOffset is less than N bytes from the end of the BLOB, 6610** [SQLITE_ERROR] is returned and no data is written. The size of the 6611** BLOB (and hence the maximum value of N+iOffset) can be determined 6612** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6613** than zero [SQLITE_ERROR] is returned and no data is written. 6614** 6615** ^An attempt to write to an expired [BLOB handle] fails with an 6616** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6617** before the [BLOB handle] expired are not rolled back by the 6618** expiration of the handle, though of course those changes might 6619** have been overwritten by the statement that expired the BLOB handle 6620** or by other independent statements. 6621** 6622** This routine only works on a [BLOB handle] which has been created 6623** by a prior successful call to [sqlite3_blob_open()] and which has not 6624** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6625** to this routine results in undefined and probably undesirable behavior. 6626** 6627** See also: [sqlite3_blob_read()]. 6628*/ 6629int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6630 6631/* 6632** CAPI3REF: Virtual File System Objects 6633** 6634** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6635** that SQLite uses to interact 6636** with the underlying operating system. Most SQLite builds come with a 6637** single default VFS that is appropriate for the host computer. 6638** New VFSes can be registered and existing VFSes can be unregistered. 6639** The following interfaces are provided. 6640** 6641** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6642** ^Names are case sensitive. 6643** ^Names are zero-terminated UTF-8 strings. 6644** ^If there is no match, a NULL pointer is returned. 6645** ^If zVfsName is NULL then the default VFS is returned. 6646** 6647** ^New VFSes are registered with sqlite3_vfs_register(). 6648** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6649** ^The same VFS can be registered multiple times without injury. 6650** ^To make an existing VFS into the default VFS, register it again 6651** with the makeDflt flag set. If two different VFSes with the 6652** same name are registered, the behavior is undefined. If a 6653** VFS is registered with a name that is NULL or an empty string, 6654** then the behavior is undefined. 6655** 6656** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6657** ^(If the default VFS is unregistered, another VFS is chosen as 6658** the default. The choice for the new VFS is arbitrary.)^ 6659*/ 6660sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6661int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6662int sqlite3_vfs_unregister(sqlite3_vfs*); 6663 6664/* 6665** CAPI3REF: Mutexes 6666** 6667** The SQLite core uses these routines for thread 6668** synchronization. Though they are intended for internal 6669** use by SQLite, code that links against SQLite is 6670** permitted to use any of these routines. 6671** 6672** The SQLite source code contains multiple implementations 6673** of these mutex routines. An appropriate implementation 6674** is selected automatically at compile-time. The following 6675** implementations are available in the SQLite core: 6676** 6677** <ul> 6678** <li> SQLITE_MUTEX_PTHREADS 6679** <li> SQLITE_MUTEX_W32 6680** <li> SQLITE_MUTEX_NOOP 6681** </ul> 6682** 6683** The SQLITE_MUTEX_NOOP implementation is a set of routines 6684** that does no real locking and is appropriate for use in 6685** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6686** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6687** and Windows. 6688** 6689** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6690** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6691** implementation is included with the library. In this case the 6692** application must supply a custom mutex implementation using the 6693** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6694** before calling sqlite3_initialize() or any other public sqlite3_ 6695** function that calls sqlite3_initialize(). 6696** 6697** ^The sqlite3_mutex_alloc() routine allocates a new 6698** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6699** routine returns NULL if it is unable to allocate the requested 6700** mutex. The argument to sqlite3_mutex_alloc() must one of these 6701** integer constants: 6702** 6703** <ul> 6704** <li> SQLITE_MUTEX_FAST 6705** <li> SQLITE_MUTEX_RECURSIVE 6706** <li> SQLITE_MUTEX_STATIC_MASTER 6707** <li> SQLITE_MUTEX_STATIC_MEM 6708** <li> SQLITE_MUTEX_STATIC_OPEN 6709** <li> SQLITE_MUTEX_STATIC_PRNG 6710** <li> SQLITE_MUTEX_STATIC_LRU 6711** <li> SQLITE_MUTEX_STATIC_PMEM 6712** <li> SQLITE_MUTEX_STATIC_APP1 6713** <li> SQLITE_MUTEX_STATIC_APP2 6714** <li> SQLITE_MUTEX_STATIC_APP3 6715** <li> SQLITE_MUTEX_STATIC_VFS1 6716** <li> SQLITE_MUTEX_STATIC_VFS2 6717** <li> SQLITE_MUTEX_STATIC_VFS3 6718** </ul> 6719** 6720** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6721** cause sqlite3_mutex_alloc() to create 6722** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6723** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6724** The mutex implementation does not need to make a distinction 6725** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6726** not want to. SQLite will only request a recursive mutex in 6727** cases where it really needs one. If a faster non-recursive mutex 6728** implementation is available on the host platform, the mutex subsystem 6729** might return such a mutex in response to SQLITE_MUTEX_FAST. 6730** 6731** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6732** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6733** a pointer to a static preexisting mutex. ^Nine static mutexes are 6734** used by the current version of SQLite. Future versions of SQLite 6735** may add additional static mutexes. Static mutexes are for internal 6736** use by SQLite only. Applications that use SQLite mutexes should 6737** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6738** SQLITE_MUTEX_RECURSIVE. 6739** 6740** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6741** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6742** returns a different mutex on every call. ^For the static 6743** mutex types, the same mutex is returned on every call that has 6744** the same type number. 6745** 6746** ^The sqlite3_mutex_free() routine deallocates a previously 6747** allocated dynamic mutex. Attempting to deallocate a static 6748** mutex results in undefined behavior. 6749** 6750** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6751** to enter a mutex. ^If another thread is already within the mutex, 6752** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6753** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6754** upon successful entry. ^(Mutexes created using 6755** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6756** In such cases, the 6757** mutex must be exited an equal number of times before another thread 6758** can enter.)^ If the same thread tries to enter any mutex other 6759** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6760** 6761** ^(Some systems (for example, Windows 95) do not support the operation 6762** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6763** will always return SQLITE_BUSY. The SQLite core only ever uses 6764** sqlite3_mutex_try() as an optimization so this is acceptable 6765** behavior.)^ 6766** 6767** ^The sqlite3_mutex_leave() routine exits a mutex that was 6768** previously entered by the same thread. The behavior 6769** is undefined if the mutex is not currently entered by the 6770** calling thread or is not currently allocated. 6771** 6772** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6773** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6774** behave as no-ops. 6775** 6776** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6777*/ 6778sqlite3_mutex *sqlite3_mutex_alloc(int); 6779void sqlite3_mutex_free(sqlite3_mutex*); 6780void sqlite3_mutex_enter(sqlite3_mutex*); 6781int sqlite3_mutex_try(sqlite3_mutex*); 6782void sqlite3_mutex_leave(sqlite3_mutex*); 6783 6784/* 6785** CAPI3REF: Mutex Methods Object 6786** 6787** An instance of this structure defines the low-level routines 6788** used to allocate and use mutexes. 6789** 6790** Usually, the default mutex implementations provided by SQLite are 6791** sufficient, however the application has the option of substituting a custom 6792** implementation for specialized deployments or systems for which SQLite 6793** does not provide a suitable implementation. In this case, the application 6794** creates and populates an instance of this structure to pass 6795** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6796** Additionally, an instance of this structure can be used as an 6797** output variable when querying the system for the current mutex 6798** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6799** 6800** ^The xMutexInit method defined by this structure is invoked as 6801** part of system initialization by the sqlite3_initialize() function. 6802** ^The xMutexInit routine is called by SQLite exactly once for each 6803** effective call to [sqlite3_initialize()]. 6804** 6805** ^The xMutexEnd method defined by this structure is invoked as 6806** part of system shutdown by the sqlite3_shutdown() function. The 6807** implementation of this method is expected to release all outstanding 6808** resources obtained by the mutex methods implementation, especially 6809** those obtained by the xMutexInit method. ^The xMutexEnd() 6810** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6811** 6812** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6813** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6814** xMutexNotheld) implement the following interfaces (respectively): 6815** 6816** <ul> 6817** <li> [sqlite3_mutex_alloc()] </li> 6818** <li> [sqlite3_mutex_free()] </li> 6819** <li> [sqlite3_mutex_enter()] </li> 6820** <li> [sqlite3_mutex_try()] </li> 6821** <li> [sqlite3_mutex_leave()] </li> 6822** <li> [sqlite3_mutex_held()] </li> 6823** <li> [sqlite3_mutex_notheld()] </li> 6824** </ul>)^ 6825** 6826** The only difference is that the public sqlite3_XXX functions enumerated 6827** above silently ignore any invocations that pass a NULL pointer instead 6828** of a valid mutex handle. The implementations of the methods defined 6829** by this structure are not required to handle this case, the results 6830** of passing a NULL pointer instead of a valid mutex handle are undefined 6831** (i.e. it is acceptable to provide an implementation that segfaults if 6832** it is passed a NULL pointer). 6833** 6834** The xMutexInit() method must be threadsafe. It must be harmless to 6835** invoke xMutexInit() multiple times within the same process and without 6836** intervening calls to xMutexEnd(). Second and subsequent calls to 6837** xMutexInit() must be no-ops. 6838** 6839** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6840** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6841** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6842** memory allocation for a fast or recursive mutex. 6843** 6844** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6845** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6846** If xMutexInit fails in any way, it is expected to clean up after itself 6847** prior to returning. 6848*/ 6849typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6850struct sqlite3_mutex_methods { 6851 int (*xMutexInit)(void); 6852 int (*xMutexEnd)(void); 6853 sqlite3_mutex *(*xMutexAlloc)(int); 6854 void (*xMutexFree)(sqlite3_mutex *); 6855 void (*xMutexEnter)(sqlite3_mutex *); 6856 int (*xMutexTry)(sqlite3_mutex *); 6857 void (*xMutexLeave)(sqlite3_mutex *); 6858 int (*xMutexHeld)(sqlite3_mutex *); 6859 int (*xMutexNotheld)(sqlite3_mutex *); 6860}; 6861 6862/* 6863** CAPI3REF: Mutex Verification Routines 6864** 6865** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6866** are intended for use inside assert() statements. The SQLite core 6867** never uses these routines except inside an assert() and applications 6868** are advised to follow the lead of the core. The SQLite core only 6869** provides implementations for these routines when it is compiled 6870** with the SQLITE_DEBUG flag. External mutex implementations 6871** are only required to provide these routines if SQLITE_DEBUG is 6872** defined and if NDEBUG is not defined. 6873** 6874** These routines should return true if the mutex in their argument 6875** is held or not held, respectively, by the calling thread. 6876** 6877** The implementation is not required to provide versions of these 6878** routines that actually work. If the implementation does not provide working 6879** versions of these routines, it should at least provide stubs that always 6880** return true so that one does not get spurious assertion failures. 6881** 6882** If the argument to sqlite3_mutex_held() is a NULL pointer then 6883** the routine should return 1. This seems counter-intuitive since 6884** clearly the mutex cannot be held if it does not exist. But 6885** the reason the mutex does not exist is because the build is not 6886** using mutexes. And we do not want the assert() containing the 6887** call to sqlite3_mutex_held() to fail, so a non-zero return is 6888** the appropriate thing to do. The sqlite3_mutex_notheld() 6889** interface should also return 1 when given a NULL pointer. 6890*/ 6891#ifndef NDEBUG 6892int sqlite3_mutex_held(sqlite3_mutex*); 6893int sqlite3_mutex_notheld(sqlite3_mutex*); 6894#endif 6895 6896/* 6897** CAPI3REF: Mutex Types 6898** 6899** The [sqlite3_mutex_alloc()] interface takes a single argument 6900** which is one of these integer constants. 6901** 6902** The set of static mutexes may change from one SQLite release to the 6903** next. Applications that override the built-in mutex logic must be 6904** prepared to accommodate additional static mutexes. 6905*/ 6906#define SQLITE_MUTEX_FAST 0 6907#define SQLITE_MUTEX_RECURSIVE 1 6908#define SQLITE_MUTEX_STATIC_MASTER 2 6909#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6910#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6911#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6912#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 6913#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6914#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6915#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6916#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6917#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6918#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6919#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 6920#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 6921#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 6922 6923/* 6924** CAPI3REF: Retrieve the mutex for a database connection 6925** METHOD: sqlite3 6926** 6927** ^This interface returns a pointer the [sqlite3_mutex] object that 6928** serializes access to the [database connection] given in the argument 6929** when the [threading mode] is Serialized. 6930** ^If the [threading mode] is Single-thread or Multi-thread then this 6931** routine returns a NULL pointer. 6932*/ 6933sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 6934 6935/* 6936** CAPI3REF: Low-Level Control Of Database Files 6937** METHOD: sqlite3 6938** 6939** ^The [sqlite3_file_control()] interface makes a direct call to the 6940** xFileControl method for the [sqlite3_io_methods] object associated 6941** with a particular database identified by the second argument. ^The 6942** name of the database is "main" for the main database or "temp" for the 6943** TEMP database, or the name that appears after the AS keyword for 6944** databases that are added using the [ATTACH] SQL command. 6945** ^A NULL pointer can be used in place of "main" to refer to the 6946** main database file. 6947** ^The third and fourth parameters to this routine 6948** are passed directly through to the second and third parameters of 6949** the xFileControl method. ^The return value of the xFileControl 6950** method becomes the return value of this routine. 6951** 6952** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 6953** a pointer to the underlying [sqlite3_file] object to be written into 6954** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 6955** case is a short-circuit path which does not actually invoke the 6956** underlying sqlite3_io_methods.xFileControl method. 6957** 6958** ^If the second parameter (zDbName) does not match the name of any 6959** open database file, then SQLITE_ERROR is returned. ^This error 6960** code is not remembered and will not be recalled by [sqlite3_errcode()] 6961** or [sqlite3_errmsg()]. The underlying xFileControl method might 6962** also return SQLITE_ERROR. There is no way to distinguish between 6963** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6964** xFileControl method. 6965** 6966** See also: [SQLITE_FCNTL_LOCKSTATE] 6967*/ 6968int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6969 6970/* 6971** CAPI3REF: Testing Interface 6972** 6973** ^The sqlite3_test_control() interface is used to read out internal 6974** state of SQLite and to inject faults into SQLite for testing 6975** purposes. ^The first parameter is an operation code that determines 6976** the number, meaning, and operation of all subsequent parameters. 6977** 6978** This interface is not for use by applications. It exists solely 6979** for verifying the correct operation of the SQLite library. Depending 6980** on how the SQLite library is compiled, this interface might not exist. 6981** 6982** The details of the operation codes, their meanings, the parameters 6983** they take, and what they do are all subject to change without notice. 6984** Unlike most of the SQLite API, this function is not guaranteed to 6985** operate consistently from one release to the next. 6986*/ 6987int sqlite3_test_control(int op, ...); 6988 6989/* 6990** CAPI3REF: Testing Interface Operation Codes 6991** 6992** These constants are the valid operation code parameters used 6993** as the first argument to [sqlite3_test_control()]. 6994** 6995** These parameters and their meanings are subject to change 6996** without notice. These values are for testing purposes only. 6997** Applications should not use any of these parameters or the 6998** [sqlite3_test_control()] interface. 6999*/ 7000#define SQLITE_TESTCTRL_FIRST 5 7001#define SQLITE_TESTCTRL_PRNG_SAVE 5 7002#define SQLITE_TESTCTRL_PRNG_RESTORE 6 7003#define SQLITE_TESTCTRL_PRNG_RESET 7 7004#define SQLITE_TESTCTRL_BITVEC_TEST 8 7005#define SQLITE_TESTCTRL_FAULT_INSTALL 9 7006#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 7007#define SQLITE_TESTCTRL_PENDING_BYTE 11 7008#define SQLITE_TESTCTRL_ASSERT 12 7009#define SQLITE_TESTCTRL_ALWAYS 13 7010#define SQLITE_TESTCTRL_RESERVE 14 7011#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7012#define SQLITE_TESTCTRL_ISKEYWORD 16 7013#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 7014#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7015#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7016#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7017#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7018#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7019#define SQLITE_TESTCTRL_BYTEORDER 22 7020#define SQLITE_TESTCTRL_ISINIT 23 7021#define SQLITE_TESTCTRL_SORTER_MMAP 24 7022#define SQLITE_TESTCTRL_IMPOSTER 25 7023#define SQLITE_TESTCTRL_LAST 25 7024 7025/* 7026** CAPI3REF: SQLite Runtime Status 7027** 7028** ^These interfaces are used to retrieve runtime status information 7029** about the performance of SQLite, and optionally to reset various 7030** highwater marks. ^The first argument is an integer code for 7031** the specific parameter to measure. ^(Recognized integer codes 7032** are of the form [status parameters | SQLITE_STATUS_...].)^ 7033** ^The current value of the parameter is returned into *pCurrent. 7034** ^The highest recorded value is returned in *pHighwater. ^If the 7035** resetFlag is true, then the highest record value is reset after 7036** *pHighwater is written. ^(Some parameters do not record the highest 7037** value. For those parameters 7038** nothing is written into *pHighwater and the resetFlag is ignored.)^ 7039** ^(Other parameters record only the highwater mark and not the current 7040** value. For these latter parameters nothing is written into *pCurrent.)^ 7041** 7042** ^The sqlite3_status() and sqlite3_status64() routines return 7043** SQLITE_OK on success and a non-zero [error code] on failure. 7044** 7045** If either the current value or the highwater mark is too large to 7046** be represented by a 32-bit integer, then the values returned by 7047** sqlite3_status() are undefined. 7048** 7049** See also: [sqlite3_db_status()] 7050*/ 7051int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 7052int sqlite3_status64( 7053 int op, 7054 sqlite3_int64 *pCurrent, 7055 sqlite3_int64 *pHighwater, 7056 int resetFlag 7057); 7058 7059 7060/* 7061** CAPI3REF: Status Parameters 7062** KEYWORDS: {status parameters} 7063** 7064** These integer constants designate various run-time status parameters 7065** that can be returned by [sqlite3_status()]. 7066** 7067** <dl> 7068** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 7069** <dd>This parameter is the current amount of memory checked out 7070** using [sqlite3_malloc()], either directly or indirectly. The 7071** figure includes calls made to [sqlite3_malloc()] by the application 7072** and internal memory usage by the SQLite library. Scratch memory 7073** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 7074** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 7075** this parameter. The amount returned is the sum of the allocation 7076** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 7077** 7078** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 7079** <dd>This parameter records the largest memory allocation request 7080** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 7081** internal equivalents). Only the value returned in the 7082** *pHighwater parameter to [sqlite3_status()] is of interest. 7083** The value written into the *pCurrent parameter is undefined.</dd>)^ 7084** 7085** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 7086** <dd>This parameter records the number of separate memory allocations 7087** currently checked out.</dd>)^ 7088** 7089** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 7090** <dd>This parameter returns the number of pages used out of the 7091** [pagecache memory allocator] that was configured using 7092** [SQLITE_CONFIG_PAGECACHE]. The 7093** value returned is in pages, not in bytes.</dd>)^ 7094** 7095** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 7096** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 7097** <dd>This parameter returns the number of bytes of page cache 7098** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 7099** buffer and where forced to overflow to [sqlite3_malloc()]. The 7100** returned value includes allocations that overflowed because they 7101** where too large (they were larger than the "sz" parameter to 7102** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 7103** no space was left in the page cache.</dd>)^ 7104** 7105** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 7106** <dd>This parameter records the largest memory allocation request 7107** handed to [pagecache memory allocator]. Only the value returned in the 7108** *pHighwater parameter to [sqlite3_status()] is of interest. 7109** The value written into the *pCurrent parameter is undefined.</dd>)^ 7110** 7111** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 7112** <dd>This parameter returns the number of allocations used out of the 7113** [scratch memory allocator] configured using 7114** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 7115** in bytes. Since a single thread may only have one scratch allocation 7116** outstanding at time, this parameter also reports the number of threads 7117** using scratch memory at the same time.</dd>)^ 7118** 7119** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 7120** <dd>This parameter returns the number of bytes of scratch memory 7121** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 7122** buffer and where forced to overflow to [sqlite3_malloc()]. The values 7123** returned include overflows because the requested allocation was too 7124** larger (that is, because the requested allocation was larger than the 7125** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 7126** slots were available. 7127** </dd>)^ 7128** 7129** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 7130** <dd>This parameter records the largest memory allocation request 7131** handed to [scratch memory allocator]. Only the value returned in the 7132** *pHighwater parameter to [sqlite3_status()] is of interest. 7133** The value written into the *pCurrent parameter is undefined.</dd>)^ 7134** 7135** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 7136** <dd>The *pHighwater parameter records the deepest parser stack. 7137** The *pCurrent value is undefined. The *pHighwater value is only 7138** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 7139** </dl> 7140** 7141** New status parameters may be added from time to time. 7142*/ 7143#define SQLITE_STATUS_MEMORY_USED 0 7144#define SQLITE_STATUS_PAGECACHE_USED 1 7145#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 7146#define SQLITE_STATUS_SCRATCH_USED 3 7147#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 7148#define SQLITE_STATUS_MALLOC_SIZE 5 7149#define SQLITE_STATUS_PARSER_STACK 6 7150#define SQLITE_STATUS_PAGECACHE_SIZE 7 7151#define SQLITE_STATUS_SCRATCH_SIZE 8 7152#define SQLITE_STATUS_MALLOC_COUNT 9 7153 7154/* 7155** CAPI3REF: Database Connection Status 7156** METHOD: sqlite3 7157** 7158** ^This interface is used to retrieve runtime status information 7159** about a single [database connection]. ^The first argument is the 7160** database connection object to be interrogated. ^The second argument 7161** is an integer constant, taken from the set of 7162** [SQLITE_DBSTATUS options], that 7163** determines the parameter to interrogate. The set of 7164** [SQLITE_DBSTATUS options] is likely 7165** to grow in future releases of SQLite. 7166** 7167** ^The current value of the requested parameter is written into *pCur 7168** and the highest instantaneous value is written into *pHiwtr. ^If 7169** the resetFlg is true, then the highest instantaneous value is 7170** reset back down to the current value. 7171** 7172** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 7173** non-zero [error code] on failure. 7174** 7175** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 7176*/ 7177int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 7178 7179/* 7180** CAPI3REF: Status Parameters for database connections 7181** KEYWORDS: {SQLITE_DBSTATUS options} 7182** 7183** These constants are the available integer "verbs" that can be passed as 7184** the second argument to the [sqlite3_db_status()] interface. 7185** 7186** New verbs may be added in future releases of SQLite. Existing verbs 7187** might be discontinued. Applications should check the return code from 7188** [sqlite3_db_status()] to make sure that the call worked. 7189** The [sqlite3_db_status()] interface will return a non-zero error code 7190** if a discontinued or unsupported verb is invoked. 7191** 7192** <dl> 7193** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 7194** <dd>This parameter returns the number of lookaside memory slots currently 7195** checked out.</dd>)^ 7196** 7197** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 7198** <dd>This parameter returns the number malloc attempts that were 7199** satisfied using lookaside memory. Only the high-water value is meaningful; 7200** the current value is always zero.)^ 7201** 7202** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 7203** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 7204** <dd>This parameter returns the number malloc attempts that might have 7205** been satisfied using lookaside memory but failed due to the amount of 7206** memory requested being larger than the lookaside slot size. 7207** Only the high-water value is meaningful; 7208** the current value is always zero.)^ 7209** 7210** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 7211** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 7212** <dd>This parameter returns the number malloc attempts that might have 7213** been satisfied using lookaside memory but failed due to all lookaside 7214** memory already being in use. 7215** Only the high-water value is meaningful; 7216** the current value is always zero.)^ 7217** 7218** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 7219** <dd>This parameter returns the approximate number of bytes of heap 7220** memory used by all pager caches associated with the database connection.)^ 7221** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 7222** 7223** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 7224** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 7225** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 7226** pager cache is shared between two or more connections the bytes of heap 7227** memory used by that pager cache is divided evenly between the attached 7228** connections.)^ In other words, if none of the pager caches associated 7229** with the database connection are shared, this request returns the same 7230** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 7231** shared, the value returned by this call will be smaller than that returned 7232** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 7233** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 7234** 7235** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 7236** <dd>This parameter returns the approximate number of bytes of heap 7237** memory used to store the schema for all databases associated 7238** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 7239** ^The full amount of memory used by the schemas is reported, even if the 7240** schema memory is shared with other database connections due to 7241** [shared cache mode] being enabled. 7242** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 7243** 7244** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 7245** <dd>This parameter returns the approximate number of bytes of heap 7246** and lookaside memory used by all prepared statements associated with 7247** the database connection.)^ 7248** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 7249** </dd> 7250** 7251** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 7252** <dd>This parameter returns the number of pager cache hits that have 7253** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 7254** is always 0. 7255** </dd> 7256** 7257** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 7258** <dd>This parameter returns the number of pager cache misses that have 7259** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 7260** is always 0. 7261** </dd> 7262** 7263** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 7264** <dd>This parameter returns the number of dirty cache entries that have 7265** been written to disk. Specifically, the number of pages written to the 7266** wal file in wal mode databases, or the number of pages written to the 7267** database file in rollback mode databases. Any pages written as part of 7268** transaction rollback or database recovery operations are not included. 7269** If an IO or other error occurs while writing a page to disk, the effect 7270** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 7271** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 7272** </dd> 7273** 7274** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 7275** <dd>This parameter returns zero for the current value if and only if 7276** all foreign key constraints (deferred or immediate) have been 7277** resolved.)^ ^The highwater mark is always 0. 7278** </dd> 7279** </dl> 7280*/ 7281#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 7282#define SQLITE_DBSTATUS_CACHE_USED 1 7283#define SQLITE_DBSTATUS_SCHEMA_USED 2 7284#define SQLITE_DBSTATUS_STMT_USED 3 7285#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 7286#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 7287#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 7288#define SQLITE_DBSTATUS_CACHE_HIT 7 7289#define SQLITE_DBSTATUS_CACHE_MISS 8 7290#define SQLITE_DBSTATUS_CACHE_WRITE 9 7291#define SQLITE_DBSTATUS_DEFERRED_FKS 10 7292#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 7293#define SQLITE_DBSTATUS_MAX 11 /* Largest defined DBSTATUS */ 7294 7295 7296/* 7297** CAPI3REF: Prepared Statement Status 7298** METHOD: sqlite3_stmt 7299** 7300** ^(Each prepared statement maintains various 7301** [SQLITE_STMTSTATUS counters] that measure the number 7302** of times it has performed specific operations.)^ These counters can 7303** be used to monitor the performance characteristics of the prepared 7304** statements. For example, if the number of table steps greatly exceeds 7305** the number of table searches or result rows, that would tend to indicate 7306** that the prepared statement is using a full table scan rather than 7307** an index. 7308** 7309** ^(This interface is used to retrieve and reset counter values from 7310** a [prepared statement]. The first argument is the prepared statement 7311** object to be interrogated. The second argument 7312** is an integer code for a specific [SQLITE_STMTSTATUS counter] 7313** to be interrogated.)^ 7314** ^The current value of the requested counter is returned. 7315** ^If the resetFlg is true, then the counter is reset to zero after this 7316** interface call returns. 7317** 7318** See also: [sqlite3_status()] and [sqlite3_db_status()]. 7319*/ 7320int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 7321 7322/* 7323** CAPI3REF: Status Parameters for prepared statements 7324** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 7325** 7326** These preprocessor macros define integer codes that name counter 7327** values associated with the [sqlite3_stmt_status()] interface. 7328** The meanings of the various counters are as follows: 7329** 7330** <dl> 7331** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 7332** <dd>^This is the number of times that SQLite has stepped forward in 7333** a table as part of a full table scan. Large numbers for this counter 7334** may indicate opportunities for performance improvement through 7335** careful use of indices.</dd> 7336** 7337** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 7338** <dd>^This is the number of sort operations that have occurred. 7339** A non-zero value in this counter may indicate an opportunity to 7340** improvement performance through careful use of indices.</dd> 7341** 7342** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 7343** <dd>^This is the number of rows inserted into transient indices that 7344** were created automatically in order to help joins run faster. 7345** A non-zero value in this counter may indicate an opportunity to 7346** improvement performance by adding permanent indices that do not 7347** need to be reinitialized each time the statement is run.</dd> 7348** 7349** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 7350** <dd>^This is the number of virtual machine operations executed 7351** by the prepared statement if that number is less than or equal 7352** to 2147483647. The number of virtual machine operations can be 7353** used as a proxy for the total work done by the prepared statement. 7354** If the number of virtual machine operations exceeds 2147483647 7355** then the value returned by this statement status code is undefined. 7356** 7357** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 7358** <dd>^This is the number of times that the prepare statement has been 7359** automatically regenerated due to schema changes or change to 7360** [bound parameters] that might affect the query plan. 7361** 7362** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 7363** <dd>^This is the number of times that the prepared statement has 7364** been run. A single "run" for the purposes of this counter is one 7365** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 7366** The counter is incremented on the first [sqlite3_step()] call of each 7367** cycle. 7368** 7369** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 7370** <dd>^This is the approximate number of bytes of heap memory 7371** used to store the prepared statement. ^This value is not actually 7372** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 7373** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 7374** </dd> 7375** </dl> 7376*/ 7377#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 7378#define SQLITE_STMTSTATUS_SORT 2 7379#define SQLITE_STMTSTATUS_AUTOINDEX 3 7380#define SQLITE_STMTSTATUS_VM_STEP 4 7381#define SQLITE_STMTSTATUS_REPREPARE 5 7382#define SQLITE_STMTSTATUS_RUN 6 7383#define SQLITE_STMTSTATUS_MEMUSED 99 7384 7385/* 7386** CAPI3REF: Custom Page Cache Object 7387** 7388** The sqlite3_pcache type is opaque. It is implemented by 7389** the pluggable module. The SQLite core has no knowledge of 7390** its size or internal structure and never deals with the 7391** sqlite3_pcache object except by holding and passing pointers 7392** to the object. 7393** 7394** See [sqlite3_pcache_methods2] for additional information. 7395*/ 7396typedef struct sqlite3_pcache sqlite3_pcache; 7397 7398/* 7399** CAPI3REF: Custom Page Cache Object 7400** 7401** The sqlite3_pcache_page object represents a single page in the 7402** page cache. The page cache will allocate instances of this 7403** object. Various methods of the page cache use pointers to instances 7404** of this object as parameters or as their return value. 7405** 7406** See [sqlite3_pcache_methods2] for additional information. 7407*/ 7408typedef struct sqlite3_pcache_page sqlite3_pcache_page; 7409struct sqlite3_pcache_page { 7410 void *pBuf; /* The content of the page */ 7411 void *pExtra; /* Extra information associated with the page */ 7412}; 7413 7414/* 7415** CAPI3REF: Application Defined Page Cache. 7416** KEYWORDS: {page cache} 7417** 7418** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 7419** register an alternative page cache implementation by passing in an 7420** instance of the sqlite3_pcache_methods2 structure.)^ 7421** In many applications, most of the heap memory allocated by 7422** SQLite is used for the page cache. 7423** By implementing a 7424** custom page cache using this API, an application can better control 7425** the amount of memory consumed by SQLite, the way in which 7426** that memory is allocated and released, and the policies used to 7427** determine exactly which parts of a database file are cached and for 7428** how long. 7429** 7430** The alternative page cache mechanism is an 7431** extreme measure that is only needed by the most demanding applications. 7432** The built-in page cache is recommended for most uses. 7433** 7434** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 7435** internal buffer by SQLite within the call to [sqlite3_config]. Hence 7436** the application may discard the parameter after the call to 7437** [sqlite3_config()] returns.)^ 7438** 7439** [[the xInit() page cache method]] 7440** ^(The xInit() method is called once for each effective 7441** call to [sqlite3_initialize()])^ 7442** (usually only once during the lifetime of the process). ^(The xInit() 7443** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 7444** The intent of the xInit() method is to set up global data structures 7445** required by the custom page cache implementation. 7446** ^(If the xInit() method is NULL, then the 7447** built-in default page cache is used instead of the application defined 7448** page cache.)^ 7449** 7450** [[the xShutdown() page cache method]] 7451** ^The xShutdown() method is called by [sqlite3_shutdown()]. 7452** It can be used to clean up 7453** any outstanding resources before process shutdown, if required. 7454** ^The xShutdown() method may be NULL. 7455** 7456** ^SQLite automatically serializes calls to the xInit method, 7457** so the xInit method need not be threadsafe. ^The 7458** xShutdown method is only called from [sqlite3_shutdown()] so it does 7459** not need to be threadsafe either. All other methods must be threadsafe 7460** in multithreaded applications. 7461** 7462** ^SQLite will never invoke xInit() more than once without an intervening 7463** call to xShutdown(). 7464** 7465** [[the xCreate() page cache methods]] 7466** ^SQLite invokes the xCreate() method to construct a new cache instance. 7467** SQLite will typically create one cache instance for each open database file, 7468** though this is not guaranteed. ^The 7469** first parameter, szPage, is the size in bytes of the pages that must 7470** be allocated by the cache. ^szPage will always a power of two. ^The 7471** second parameter szExtra is a number of bytes of extra storage 7472** associated with each page cache entry. ^The szExtra parameter will 7473** a number less than 250. SQLite will use the 7474** extra szExtra bytes on each page to store metadata about the underlying 7475** database page on disk. The value passed into szExtra depends 7476** on the SQLite version, the target platform, and how SQLite was compiled. 7477** ^The third argument to xCreate(), bPurgeable, is true if the cache being 7478** created will be used to cache database pages of a file stored on disk, or 7479** false if it is used for an in-memory database. The cache implementation 7480** does not have to do anything special based with the value of bPurgeable; 7481** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 7482** never invoke xUnpin() except to deliberately delete a page. 7483** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 7484** false will always have the "discard" flag set to true. 7485** ^Hence, a cache created with bPurgeable false will 7486** never contain any unpinned pages. 7487** 7488** [[the xCachesize() page cache method]] 7489** ^(The xCachesize() method may be called at any time by SQLite to set the 7490** suggested maximum cache-size (number of pages stored by) the cache 7491** instance passed as the first argument. This is the value configured using 7492** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 7493** parameter, the implementation is not required to do anything with this 7494** value; it is advisory only. 7495** 7496** [[the xPagecount() page cache methods]] 7497** The xPagecount() method must return the number of pages currently 7498** stored in the cache, both pinned and unpinned. 7499** 7500** [[the xFetch() page cache methods]] 7501** The xFetch() method locates a page in the cache and returns a pointer to 7502** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 7503** The pBuf element of the returned sqlite3_pcache_page object will be a 7504** pointer to a buffer of szPage bytes used to store the content of a 7505** single database page. The pExtra element of sqlite3_pcache_page will be 7506** a pointer to the szExtra bytes of extra storage that SQLite has requested 7507** for each entry in the page cache. 7508** 7509** The page to be fetched is determined by the key. ^The minimum key value 7510** is 1. After it has been retrieved using xFetch, the page is considered 7511** to be "pinned". 7512** 7513** If the requested page is already in the page cache, then the page cache 7514** implementation must return a pointer to the page buffer with its content 7515** intact. If the requested page is not already in the cache, then the 7516** cache implementation should use the value of the createFlag 7517** parameter to help it determined what action to take: 7518** 7519** <table border=1 width=85% align=center> 7520** <tr><th> createFlag <th> Behavior when page is not already in cache 7521** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 7522** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 7523** Otherwise return NULL. 7524** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 7525** NULL if allocating a new page is effectively impossible. 7526** </table> 7527** 7528** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 7529** will only use a createFlag of 2 after a prior call with a createFlag of 1 7530** failed.)^ In between the to xFetch() calls, SQLite may 7531** attempt to unpin one or more cache pages by spilling the content of 7532** pinned pages to disk and synching the operating system disk cache. 7533** 7534** [[the xUnpin() page cache method]] 7535** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 7536** as its second argument. If the third parameter, discard, is non-zero, 7537** then the page must be evicted from the cache. 7538** ^If the discard parameter is 7539** zero, then the page may be discarded or retained at the discretion of 7540** page cache implementation. ^The page cache implementation 7541** may choose to evict unpinned pages at any time. 7542** 7543** The cache must not perform any reference counting. A single 7544** call to xUnpin() unpins the page regardless of the number of prior calls 7545** to xFetch(). 7546** 7547** [[the xRekey() page cache methods]] 7548** The xRekey() method is used to change the key value associated with the 7549** page passed as the second argument. If the cache 7550** previously contains an entry associated with newKey, it must be 7551** discarded. ^Any prior cache entry associated with newKey is guaranteed not 7552** to be pinned. 7553** 7554** When SQLite calls the xTruncate() method, the cache must discard all 7555** existing cache entries with page numbers (keys) greater than or equal 7556** to the value of the iLimit parameter passed to xTruncate(). If any 7557** of these pages are pinned, they are implicitly unpinned, meaning that 7558** they can be safely discarded. 7559** 7560** [[the xDestroy() page cache method]] 7561** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 7562** All resources associated with the specified cache should be freed. ^After 7563** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 7564** handle invalid, and will not use it with any other sqlite3_pcache_methods2 7565** functions. 7566** 7567** [[the xShrink() page cache method]] 7568** ^SQLite invokes the xShrink() method when it wants the page cache to 7569** free up as much of heap memory as possible. The page cache implementation 7570** is not obligated to free any memory, but well-behaved implementations should 7571** do their best. 7572*/ 7573typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 7574struct sqlite3_pcache_methods2 { 7575 int iVersion; 7576 void *pArg; 7577 int (*xInit)(void*); 7578 void (*xShutdown)(void*); 7579 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 7580 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7581 int (*xPagecount)(sqlite3_pcache*); 7582 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7583 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 7584 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 7585 unsigned oldKey, unsigned newKey); 7586 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7587 void (*xDestroy)(sqlite3_pcache*); 7588 void (*xShrink)(sqlite3_pcache*); 7589}; 7590 7591/* 7592** This is the obsolete pcache_methods object that has now been replaced 7593** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 7594** retained in the header file for backwards compatibility only. 7595*/ 7596typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 7597struct sqlite3_pcache_methods { 7598 void *pArg; 7599 int (*xInit)(void*); 7600 void (*xShutdown)(void*); 7601 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 7602 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7603 int (*xPagecount)(sqlite3_pcache*); 7604 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7605 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 7606 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 7607 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7608 void (*xDestroy)(sqlite3_pcache*); 7609}; 7610 7611 7612/* 7613** CAPI3REF: Online Backup Object 7614** 7615** The sqlite3_backup object records state information about an ongoing 7616** online backup operation. ^The sqlite3_backup object is created by 7617** a call to [sqlite3_backup_init()] and is destroyed by a call to 7618** [sqlite3_backup_finish()]. 7619** 7620** See Also: [Using the SQLite Online Backup API] 7621*/ 7622typedef struct sqlite3_backup sqlite3_backup; 7623 7624/* 7625** CAPI3REF: Online Backup API. 7626** 7627** The backup API copies the content of one database into another. 7628** It is useful either for creating backups of databases or 7629** for copying in-memory databases to or from persistent files. 7630** 7631** See Also: [Using the SQLite Online Backup API] 7632** 7633** ^SQLite holds a write transaction open on the destination database file 7634** for the duration of the backup operation. 7635** ^The source database is read-locked only while it is being read; 7636** it is not locked continuously for the entire backup operation. 7637** ^Thus, the backup may be performed on a live source database without 7638** preventing other database connections from 7639** reading or writing to the source database while the backup is underway. 7640** 7641** ^(To perform a backup operation: 7642** <ol> 7643** <li><b>sqlite3_backup_init()</b> is called once to initialize the 7644** backup, 7645** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 7646** the data between the two databases, and finally 7647** <li><b>sqlite3_backup_finish()</b> is called to release all resources 7648** associated with the backup operation. 7649** </ol>)^ 7650** There should be exactly one call to sqlite3_backup_finish() for each 7651** successful call to sqlite3_backup_init(). 7652** 7653** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 7654** 7655** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 7656** [database connection] associated with the destination database 7657** and the database name, respectively. 7658** ^The database name is "main" for the main database, "temp" for the 7659** temporary database, or the name specified after the AS keyword in 7660** an [ATTACH] statement for an attached database. 7661** ^The S and M arguments passed to 7662** sqlite3_backup_init(D,N,S,M) identify the [database connection] 7663** and database name of the source database, respectively. 7664** ^The source and destination [database connections] (parameters S and D) 7665** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 7666** an error. 7667** 7668** ^A call to sqlite3_backup_init() will fail, returning NULL, if 7669** there is already a read or read-write transaction open on the 7670** destination database. 7671** 7672** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 7673** returned and an error code and error message are stored in the 7674** destination [database connection] D. 7675** ^The error code and message for the failed call to sqlite3_backup_init() 7676** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 7677** [sqlite3_errmsg16()] functions. 7678** ^A successful call to sqlite3_backup_init() returns a pointer to an 7679** [sqlite3_backup] object. 7680** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 7681** sqlite3_backup_finish() functions to perform the specified backup 7682** operation. 7683** 7684** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 7685** 7686** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 7687** the source and destination databases specified by [sqlite3_backup] object B. 7688** ^If N is negative, all remaining source pages are copied. 7689** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 7690** are still more pages to be copied, then the function returns [SQLITE_OK]. 7691** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 7692** from source to destination, then it returns [SQLITE_DONE]. 7693** ^If an error occurs while running sqlite3_backup_step(B,N), 7694** then an [error code] is returned. ^As well as [SQLITE_OK] and 7695** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 7696** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 7697** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 7698** 7699** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 7700** <ol> 7701** <li> the destination database was opened read-only, or 7702** <li> the destination database is using write-ahead-log journaling 7703** and the destination and source page sizes differ, or 7704** <li> the destination database is an in-memory database and the 7705** destination and source page sizes differ. 7706** </ol>)^ 7707** 7708** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 7709** the [sqlite3_busy_handler | busy-handler function] 7710** is invoked (if one is specified). ^If the 7711** busy-handler returns non-zero before the lock is available, then 7712** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 7713** sqlite3_backup_step() can be retried later. ^If the source 7714** [database connection] 7715** is being used to write to the source database when sqlite3_backup_step() 7716** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 7717** case the call to sqlite3_backup_step() can be retried later on. ^(If 7718** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 7719** [SQLITE_READONLY] is returned, then 7720** there is no point in retrying the call to sqlite3_backup_step(). These 7721** errors are considered fatal.)^ The application must accept 7722** that the backup operation has failed and pass the backup operation handle 7723** to the sqlite3_backup_finish() to release associated resources. 7724** 7725** ^The first call to sqlite3_backup_step() obtains an exclusive lock 7726** on the destination file. ^The exclusive lock is not released until either 7727** sqlite3_backup_finish() is called or the backup operation is complete 7728** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 7729** sqlite3_backup_step() obtains a [shared lock] on the source database that 7730** lasts for the duration of the sqlite3_backup_step() call. 7731** ^Because the source database is not locked between calls to 7732** sqlite3_backup_step(), the source database may be modified mid-way 7733** through the backup process. ^If the source database is modified by an 7734** external process or via a database connection other than the one being 7735** used by the backup operation, then the backup will be automatically 7736** restarted by the next call to sqlite3_backup_step(). ^If the source 7737** database is modified by the using the same database connection as is used 7738** by the backup operation, then the backup database is automatically 7739** updated at the same time. 7740** 7741** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 7742** 7743** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 7744** application wishes to abandon the backup operation, the application 7745** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 7746** ^The sqlite3_backup_finish() interfaces releases all 7747** resources associated with the [sqlite3_backup] object. 7748** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 7749** active write-transaction on the destination database is rolled back. 7750** The [sqlite3_backup] object is invalid 7751** and may not be used following a call to sqlite3_backup_finish(). 7752** 7753** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 7754** sqlite3_backup_step() errors occurred, regardless or whether or not 7755** sqlite3_backup_step() completed. 7756** ^If an out-of-memory condition or IO error occurred during any prior 7757** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 7758** sqlite3_backup_finish() returns the corresponding [error code]. 7759** 7760** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 7761** is not a permanent error and does not affect the return value of 7762** sqlite3_backup_finish(). 7763** 7764** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 7765** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 7766** 7767** ^The sqlite3_backup_remaining() routine returns the number of pages still 7768** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 7769** ^The sqlite3_backup_pagecount() routine returns the total number of pages 7770** in the source database at the conclusion of the most recent 7771** sqlite3_backup_step(). 7772** ^(The values returned by these functions are only updated by 7773** sqlite3_backup_step(). If the source database is modified in a way that 7774** changes the size of the source database or the number of pages remaining, 7775** those changes are not reflected in the output of sqlite3_backup_pagecount() 7776** and sqlite3_backup_remaining() until after the next 7777** sqlite3_backup_step().)^ 7778** 7779** <b>Concurrent Usage of Database Handles</b> 7780** 7781** ^The source [database connection] may be used by the application for other 7782** purposes while a backup operation is underway or being initialized. 7783** ^If SQLite is compiled and configured to support threadsafe database 7784** connections, then the source database connection may be used concurrently 7785** from within other threads. 7786** 7787** However, the application must guarantee that the destination 7788** [database connection] is not passed to any other API (by any thread) after 7789** sqlite3_backup_init() is called and before the corresponding call to 7790** sqlite3_backup_finish(). SQLite does not currently check to see 7791** if the application incorrectly accesses the destination [database connection] 7792** and so no error code is reported, but the operations may malfunction 7793** nevertheless. Use of the destination database connection while a 7794** backup is in progress might also also cause a mutex deadlock. 7795** 7796** If running in [shared cache mode], the application must 7797** guarantee that the shared cache used by the destination database 7798** is not accessed while the backup is running. In practice this means 7799** that the application must guarantee that the disk file being 7800** backed up to is not accessed by any connection within the process, 7801** not just the specific connection that was passed to sqlite3_backup_init(). 7802** 7803** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7804** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7805** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7806** APIs are not strictly speaking threadsafe. If they are invoked at the 7807** same time as another thread is invoking sqlite3_backup_step() it is 7808** possible that they return invalid values. 7809*/ 7810sqlite3_backup *sqlite3_backup_init( 7811 sqlite3 *pDest, /* Destination database handle */ 7812 const char *zDestName, /* Destination database name */ 7813 sqlite3 *pSource, /* Source database handle */ 7814 const char *zSourceName /* Source database name */ 7815); 7816int sqlite3_backup_step(sqlite3_backup *p, int nPage); 7817int sqlite3_backup_finish(sqlite3_backup *p); 7818int sqlite3_backup_remaining(sqlite3_backup *p); 7819int sqlite3_backup_pagecount(sqlite3_backup *p); 7820 7821/* 7822** CAPI3REF: Unlock Notification 7823** METHOD: sqlite3 7824** 7825** ^When running in shared-cache mode, a database operation may fail with 7826** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7827** individual tables within the shared-cache cannot be obtained. See 7828** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7829** ^This API may be used to register a callback that SQLite will invoke 7830** when the connection currently holding the required lock relinquishes it. 7831** ^This API is only available if the library was compiled with the 7832** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7833** 7834** See Also: [Using the SQLite Unlock Notification Feature]. 7835** 7836** ^Shared-cache locks are released when a database connection concludes 7837** its current transaction, either by committing it or rolling it back. 7838** 7839** ^When a connection (known as the blocked connection) fails to obtain a 7840** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7841** identity of the database connection (the blocking connection) that 7842** has locked the required resource is stored internally. ^After an 7843** application receives an SQLITE_LOCKED error, it may call the 7844** sqlite3_unlock_notify() method with the blocked connection handle as 7845** the first argument to register for a callback that will be invoked 7846** when the blocking connections current transaction is concluded. ^The 7847** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7848** call that concludes the blocking connections transaction. 7849** 7850** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7851** there is a chance that the blocking connection will have already 7852** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7853** If this happens, then the specified callback is invoked immediately, 7854** from within the call to sqlite3_unlock_notify().)^ 7855** 7856** ^If the blocked connection is attempting to obtain a write-lock on a 7857** shared-cache table, and more than one other connection currently holds 7858** a read-lock on the same table, then SQLite arbitrarily selects one of 7859** the other connections to use as the blocking connection. 7860** 7861** ^(There may be at most one unlock-notify callback registered by a 7862** blocked connection. If sqlite3_unlock_notify() is called when the 7863** blocked connection already has a registered unlock-notify callback, 7864** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7865** called with a NULL pointer as its second argument, then any existing 7866** unlock-notify callback is canceled. ^The blocked connections 7867** unlock-notify callback may also be canceled by closing the blocked 7868** connection using [sqlite3_close()]. 7869** 7870** The unlock-notify callback is not reentrant. If an application invokes 7871** any sqlite3_xxx API functions from within an unlock-notify callback, a 7872** crash or deadlock may be the result. 7873** 7874** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7875** returns SQLITE_OK. 7876** 7877** <b>Callback Invocation Details</b> 7878** 7879** When an unlock-notify callback is registered, the application provides a 7880** single void* pointer that is passed to the callback when it is invoked. 7881** However, the signature of the callback function allows SQLite to pass 7882** it an array of void* context pointers. The first argument passed to 7883** an unlock-notify callback is a pointer to an array of void* pointers, 7884** and the second is the number of entries in the array. 7885** 7886** When a blocking connections transaction is concluded, there may be 7887** more than one blocked connection that has registered for an unlock-notify 7888** callback. ^If two or more such blocked connections have specified the 7889** same callback function, then instead of invoking the callback function 7890** multiple times, it is invoked once with the set of void* context pointers 7891** specified by the blocked connections bundled together into an array. 7892** This gives the application an opportunity to prioritize any actions 7893** related to the set of unblocked database connections. 7894** 7895** <b>Deadlock Detection</b> 7896** 7897** Assuming that after registering for an unlock-notify callback a 7898** database waits for the callback to be issued before taking any further 7899** action (a reasonable assumption), then using this API may cause the 7900** application to deadlock. For example, if connection X is waiting for 7901** connection Y's transaction to be concluded, and similarly connection 7902** Y is waiting on connection X's transaction, then neither connection 7903** will proceed and the system may remain deadlocked indefinitely. 7904** 7905** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7906** detection. ^If a given call to sqlite3_unlock_notify() would put the 7907** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7908** unlock-notify callback is registered. The system is said to be in 7909** a deadlocked state if connection A has registered for an unlock-notify 7910** callback on the conclusion of connection B's transaction, and connection 7911** B has itself registered for an unlock-notify callback when connection 7912** A's transaction is concluded. ^Indirect deadlock is also detected, so 7913** the system is also considered to be deadlocked if connection B has 7914** registered for an unlock-notify callback on the conclusion of connection 7915** C's transaction, where connection C is waiting on connection A. ^Any 7916** number of levels of indirection are allowed. 7917** 7918** <b>The "DROP TABLE" Exception</b> 7919** 7920** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7921** always appropriate to call sqlite3_unlock_notify(). There is however, 7922** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7923** SQLite checks if there are any currently executing SELECT statements 7924** that belong to the same connection. If there are, SQLITE_LOCKED is 7925** returned. In this case there is no "blocking connection", so invoking 7926** sqlite3_unlock_notify() results in the unlock-notify callback being 7927** invoked immediately. If the application then re-attempts the "DROP TABLE" 7928** or "DROP INDEX" query, an infinite loop might be the result. 7929** 7930** One way around this problem is to check the extended error code returned 7931** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7932** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7933** the special "DROP TABLE/INDEX" case, the extended error code is just 7934** SQLITE_LOCKED.)^ 7935*/ 7936int sqlite3_unlock_notify( 7937 sqlite3 *pBlocked, /* Waiting connection */ 7938 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7939 void *pNotifyArg /* Argument to pass to xNotify */ 7940); 7941 7942 7943/* 7944** CAPI3REF: String Comparison 7945** 7946** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7947** and extensions to compare the contents of two buffers containing UTF-8 7948** strings in a case-independent fashion, using the same definition of "case 7949** independence" that SQLite uses internally when comparing identifiers. 7950*/ 7951int sqlite3_stricmp(const char *, const char *); 7952int sqlite3_strnicmp(const char *, const char *, int); 7953 7954/* 7955** CAPI3REF: String Globbing 7956* 7957** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 7958** string X matches the [GLOB] pattern P. 7959** ^The definition of [GLOB] pattern matching used in 7960** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7961** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 7962** is case sensitive. 7963** 7964** Note that this routine returns zero on a match and non-zero if the strings 7965** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7966** 7967** See also: [sqlite3_strlike()]. 7968*/ 7969int sqlite3_strglob(const char *zGlob, const char *zStr); 7970 7971/* 7972** CAPI3REF: String LIKE Matching 7973* 7974** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 7975** string X matches the [LIKE] pattern P with escape character E. 7976** ^The definition of [LIKE] pattern matching used in 7977** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 7978** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 7979** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 7980** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 7981** insensitive - equivalent upper and lower case ASCII characters match 7982** one another. 7983** 7984** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 7985** only ASCII characters are case folded. 7986** 7987** Note that this routine returns zero on a match and non-zero if the strings 7988** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7989** 7990** See also: [sqlite3_strglob()]. 7991*/ 7992int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 7993 7994/* 7995** CAPI3REF: Error Logging Interface 7996** 7997** ^The [sqlite3_log()] interface writes a message into the [error log] 7998** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7999** ^If logging is enabled, the zFormat string and subsequent arguments are 8000** used with [sqlite3_snprintf()] to generate the final output string. 8001** 8002** The sqlite3_log() interface is intended for use by extensions such as 8003** virtual tables, collating functions, and SQL functions. While there is 8004** nothing to prevent an application from calling sqlite3_log(), doing so 8005** is considered bad form. 8006** 8007** The zFormat string must not be NULL. 8008** 8009** To avoid deadlocks and other threading problems, the sqlite3_log() routine 8010** will not use dynamically allocated memory. The log message is stored in 8011** a fixed-length buffer on the stack. If the log message is longer than 8012** a few hundred characters, it will be truncated to the length of the 8013** buffer. 8014*/ 8015void sqlite3_log(int iErrCode, const char *zFormat, ...); 8016 8017/* 8018** CAPI3REF: Write-Ahead Log Commit Hook 8019** METHOD: sqlite3 8020** 8021** ^The [sqlite3_wal_hook()] function is used to register a callback that 8022** is invoked each time data is committed to a database in wal mode. 8023** 8024** ^(The callback is invoked by SQLite after the commit has taken place and 8025** the associated write-lock on the database released)^, so the implementation 8026** may read, write or [checkpoint] the database as required. 8027** 8028** ^The first parameter passed to the callback function when it is invoked 8029** is a copy of the third parameter passed to sqlite3_wal_hook() when 8030** registering the callback. ^The second is a copy of the database handle. 8031** ^The third parameter is the name of the database that was written to - 8032** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 8033** is the number of pages currently in the write-ahead log file, 8034** including those that were just committed. 8035** 8036** The callback function should normally return [SQLITE_OK]. ^If an error 8037** code is returned, that error will propagate back up through the 8038** SQLite code base to cause the statement that provoked the callback 8039** to report an error, though the commit will have still occurred. If the 8040** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 8041** that does not correspond to any valid SQLite error code, the results 8042** are undefined. 8043** 8044** A single database handle may have at most a single write-ahead log callback 8045** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 8046** previously registered write-ahead log callback. ^Note that the 8047** [sqlite3_wal_autocheckpoint()] interface and the 8048** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 8049** overwrite any prior [sqlite3_wal_hook()] settings. 8050*/ 8051void *sqlite3_wal_hook( 8052 sqlite3*, 8053 int(*)(void *,sqlite3*,const char*,int), 8054 void* 8055); 8056 8057/* 8058** CAPI3REF: Configure an auto-checkpoint 8059** METHOD: sqlite3 8060** 8061** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 8062** [sqlite3_wal_hook()] that causes any database on [database connection] D 8063** to automatically [checkpoint] 8064** after committing a transaction if there are N or 8065** more frames in the [write-ahead log] file. ^Passing zero or 8066** a negative value as the nFrame parameter disables automatic 8067** checkpoints entirely. 8068** 8069** ^The callback registered by this function replaces any existing callback 8070** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 8071** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 8072** configured by this function. 8073** 8074** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 8075** from SQL. 8076** 8077** ^Checkpoints initiated by this mechanism are 8078** [sqlite3_wal_checkpoint_v2|PASSIVE]. 8079** 8080** ^Every new [database connection] defaults to having the auto-checkpoint 8081** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 8082** pages. The use of this interface 8083** is only necessary if the default setting is found to be suboptimal 8084** for a particular application. 8085*/ 8086int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 8087 8088/* 8089** CAPI3REF: Checkpoint a database 8090** METHOD: sqlite3 8091** 8092** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 8093** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 8094** 8095** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 8096** [write-ahead log] for database X on [database connection] D to be 8097** transferred into the database file and for the write-ahead log to 8098** be reset. See the [checkpointing] documentation for addition 8099** information. 8100** 8101** This interface used to be the only way to cause a checkpoint to 8102** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 8103** interface was added. This interface is retained for backwards 8104** compatibility and as a convenience for applications that need to manually 8105** start a callback but which do not need the full power (and corresponding 8106** complication) of [sqlite3_wal_checkpoint_v2()]. 8107*/ 8108int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 8109 8110/* 8111** CAPI3REF: Checkpoint a database 8112** METHOD: sqlite3 8113** 8114** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 8115** operation on database X of [database connection] D in mode M. Status 8116** information is written back into integers pointed to by L and C.)^ 8117** ^(The M parameter must be a valid [checkpoint mode]:)^ 8118** 8119** <dl> 8120** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 8121** ^Checkpoint as many frames as possible without waiting for any database 8122** readers or writers to finish, then sync the database file if all frames 8123** in the log were checkpointed. ^The [busy-handler callback] 8124** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 8125** ^On the other hand, passive mode might leave the checkpoint unfinished 8126** if there are concurrent readers or writers. 8127** 8128** <dt>SQLITE_CHECKPOINT_FULL<dd> 8129** ^This mode blocks (it invokes the 8130** [sqlite3_busy_handler|busy-handler callback]) until there is no 8131** database writer and all readers are reading from the most recent database 8132** snapshot. ^It then checkpoints all frames in the log file and syncs the 8133** database file. ^This mode blocks new database writers while it is pending, 8134** but new database readers are allowed to continue unimpeded. 8135** 8136** <dt>SQLITE_CHECKPOINT_RESTART<dd> 8137** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 8138** that after checkpointing the log file it blocks (calls the 8139** [busy-handler callback]) 8140** until all readers are reading from the database file only. ^This ensures 8141** that the next writer will restart the log file from the beginning. 8142** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 8143** database writer attempts while it is pending, but does not impede readers. 8144** 8145** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 8146** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 8147** addition that it also truncates the log file to zero bytes just prior 8148** to a successful return. 8149** </dl> 8150** 8151** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 8152** the log file or to -1 if the checkpoint could not run because 8153** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 8154** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 8155** log file (including any that were already checkpointed before the function 8156** was called) or to -1 if the checkpoint could not run due to an error or 8157** because the database is not in WAL mode. ^Note that upon successful 8158** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 8159** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 8160** 8161** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 8162** any other process is running a checkpoint operation at the same time, the 8163** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 8164** busy-handler configured, it will not be invoked in this case. 8165** 8166** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 8167** exclusive "writer" lock on the database file. ^If the writer lock cannot be 8168** obtained immediately, and a busy-handler is configured, it is invoked and 8169** the writer lock retried until either the busy-handler returns 0 or the lock 8170** is successfully obtained. ^The busy-handler is also invoked while waiting for 8171** database readers as described above. ^If the busy-handler returns 0 before 8172** the writer lock is obtained or while waiting for database readers, the 8173** checkpoint operation proceeds from that point in the same way as 8174** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 8175** without blocking any further. ^SQLITE_BUSY is returned in this case. 8176** 8177** ^If parameter zDb is NULL or points to a zero length string, then the 8178** specified operation is attempted on all WAL databases [attached] to 8179** [database connection] db. In this case the 8180** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 8181** an SQLITE_BUSY error is encountered when processing one or more of the 8182** attached WAL databases, the operation is still attempted on any remaining 8183** attached databases and SQLITE_BUSY is returned at the end. ^If any other 8184** error occurs while processing an attached database, processing is abandoned 8185** and the error code is returned to the caller immediately. ^If no error 8186** (SQLITE_BUSY or otherwise) is encountered while processing the attached 8187** databases, SQLITE_OK is returned. 8188** 8189** ^If database zDb is the name of an attached database that is not in WAL 8190** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 8191** zDb is not NULL (or a zero length string) and is not the name of any 8192** attached database, SQLITE_ERROR is returned to the caller. 8193** 8194** ^Unless it returns SQLITE_MISUSE, 8195** the sqlite3_wal_checkpoint_v2() interface 8196** sets the error information that is queried by 8197** [sqlite3_errcode()] and [sqlite3_errmsg()]. 8198** 8199** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 8200** from SQL. 8201*/ 8202int sqlite3_wal_checkpoint_v2( 8203 sqlite3 *db, /* Database handle */ 8204 const char *zDb, /* Name of attached database (or NULL) */ 8205 int eMode, /* SQLITE_CHECKPOINT_* value */ 8206 int *pnLog, /* OUT: Size of WAL log in frames */ 8207 int *pnCkpt /* OUT: Total number of frames checkpointed */ 8208); 8209 8210/* 8211** CAPI3REF: Checkpoint Mode Values 8212** KEYWORDS: {checkpoint mode} 8213** 8214** These constants define all valid values for the "checkpoint mode" passed 8215** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 8216** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 8217** meaning of each of these checkpoint modes. 8218*/ 8219#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 8220#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 8221#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 8222#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 8223 8224/* 8225** CAPI3REF: Virtual Table Interface Configuration 8226** 8227** This function may be called by either the [xConnect] or [xCreate] method 8228** of a [virtual table] implementation to configure 8229** various facets of the virtual table interface. 8230** 8231** If this interface is invoked outside the context of an xConnect or 8232** xCreate virtual table method then the behavior is undefined. 8233** 8234** At present, there is only one option that may be configured using 8235** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 8236** may be added in the future. 8237*/ 8238int sqlite3_vtab_config(sqlite3*, int op, ...); 8239 8240/* 8241** CAPI3REF: Virtual Table Configuration Options 8242** 8243** These macros define the various options to the 8244** [sqlite3_vtab_config()] interface that [virtual table] implementations 8245** can use to customize and optimize their behavior. 8246** 8247** <dl> 8248** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 8249** <dd>Calls of the form 8250** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 8251** where X is an integer. If X is zero, then the [virtual table] whose 8252** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 8253** support constraints. In this configuration (which is the default) if 8254** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 8255** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 8256** specified as part of the users SQL statement, regardless of the actual 8257** ON CONFLICT mode specified. 8258** 8259** If X is non-zero, then the virtual table implementation guarantees 8260** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 8261** any modifications to internal or persistent data structures have been made. 8262** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 8263** is able to roll back a statement or database transaction, and abandon 8264** or continue processing the current SQL statement as appropriate. 8265** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 8266** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 8267** had been ABORT. 8268** 8269** Virtual table implementations that are required to handle OR REPLACE 8270** must do so within the [xUpdate] method. If a call to the 8271** [sqlite3_vtab_on_conflict()] function indicates that the current ON 8272** CONFLICT policy is REPLACE, the virtual table implementation should 8273** silently replace the appropriate rows within the xUpdate callback and 8274** return SQLITE_OK. Or, if this is not possible, it may return 8275** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 8276** constraint handling. 8277** </dl> 8278*/ 8279#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 8280 8281/* 8282** CAPI3REF: Determine The Virtual Table Conflict Policy 8283** 8284** This function may only be called from within a call to the [xUpdate] method 8285** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 8286** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 8287** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 8288** of the SQL statement that triggered the call to the [xUpdate] method of the 8289** [virtual table]. 8290*/ 8291int sqlite3_vtab_on_conflict(sqlite3 *); 8292 8293/* 8294** CAPI3REF: Conflict resolution modes 8295** KEYWORDS: {conflict resolution mode} 8296** 8297** These constants are returned by [sqlite3_vtab_on_conflict()] to 8298** inform a [virtual table] implementation what the [ON CONFLICT] mode 8299** is for the SQL statement being evaluated. 8300** 8301** Note that the [SQLITE_IGNORE] constant is also used as a potential 8302** return value from the [sqlite3_set_authorizer()] callback and that 8303** [SQLITE_ABORT] is also a [result code]. 8304*/ 8305#define SQLITE_ROLLBACK 1 8306/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 8307#define SQLITE_FAIL 3 8308/* #define SQLITE_ABORT 4 // Also an error code */ 8309#define SQLITE_REPLACE 5 8310 8311/* 8312** CAPI3REF: Prepared Statement Scan Status Opcodes 8313** KEYWORDS: {scanstatus options} 8314** 8315** The following constants can be used for the T parameter to the 8316** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 8317** different metric for sqlite3_stmt_scanstatus() to return. 8318** 8319** When the value returned to V is a string, space to hold that string is 8320** managed by the prepared statement S and will be automatically freed when 8321** S is finalized. 8322** 8323** <dl> 8324** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 8325** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 8326** set to the total number of times that the X-th loop has run.</dd> 8327** 8328** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 8329** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 8330** to the total number of rows examined by all iterations of the X-th loop.</dd> 8331** 8332** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 8333** <dd>^The "double" variable pointed to by the T parameter will be set to the 8334** query planner's estimate for the average number of rows output from each 8335** iteration of the X-th loop. If the query planner's estimates was accurate, 8336** then this value will approximate the quotient NVISIT/NLOOP and the 8337** product of this value for all prior loops with the same SELECTID will 8338** be the NLOOP value for the current loop. 8339** 8340** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 8341** <dd>^The "const char *" variable pointed to by the T parameter will be set 8342** to a zero-terminated UTF-8 string containing the name of the index or table 8343** used for the X-th loop. 8344** 8345** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 8346** <dd>^The "const char *" variable pointed to by the T parameter will be set 8347** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 8348** description for the X-th loop. 8349** 8350** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 8351** <dd>^The "int" variable pointed to by the T parameter will be set to the 8352** "select-id" for the X-th loop. The select-id identifies which query or 8353** subquery the loop is part of. The main query has a select-id of zero. 8354** The select-id is the same value as is output in the first column 8355** of an [EXPLAIN QUERY PLAN] query. 8356** </dl> 8357*/ 8358#define SQLITE_SCANSTAT_NLOOP 0 8359#define SQLITE_SCANSTAT_NVISIT 1 8360#define SQLITE_SCANSTAT_EST 2 8361#define SQLITE_SCANSTAT_NAME 3 8362#define SQLITE_SCANSTAT_EXPLAIN 4 8363#define SQLITE_SCANSTAT_SELECTID 5 8364 8365/* 8366** CAPI3REF: Prepared Statement Scan Status 8367** METHOD: sqlite3_stmt 8368** 8369** This interface returns information about the predicted and measured 8370** performance for pStmt. Advanced applications can use this 8371** interface to compare the predicted and the measured performance and 8372** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 8373** 8374** Since this interface is expected to be rarely used, it is only 8375** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 8376** compile-time option. 8377** 8378** The "iScanStatusOp" parameter determines which status information to return. 8379** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 8380** of this interface is undefined. 8381** ^The requested measurement is written into a variable pointed to by 8382** the "pOut" parameter. 8383** Parameter "idx" identifies the specific loop to retrieve statistics for. 8384** Loops are numbered starting from zero. ^If idx is out of range - less than 8385** zero or greater than or equal to the total number of loops used to implement 8386** the statement - a non-zero value is returned and the variable that pOut 8387** points to is unchanged. 8388** 8389** ^Statistics might not be available for all loops in all statements. ^In cases 8390** where there exist loops with no available statistics, this function behaves 8391** as if the loop did not exist - it returns non-zero and leave the variable 8392** that pOut points to unchanged. 8393** 8394** See also: [sqlite3_stmt_scanstatus_reset()] 8395*/ 8396int sqlite3_stmt_scanstatus( 8397 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 8398 int idx, /* Index of loop to report on */ 8399 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 8400 void *pOut /* Result written here */ 8401); 8402 8403/* 8404** CAPI3REF: Zero Scan-Status Counters 8405** METHOD: sqlite3_stmt 8406** 8407** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 8408** 8409** This API is only available if the library is built with pre-processor 8410** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 8411*/ 8412void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 8413 8414/* 8415** CAPI3REF: Flush caches to disk mid-transaction 8416** 8417** ^If a write-transaction is open on [database connection] D when the 8418** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 8419** pages in the pager-cache that are not currently in use are written out 8420** to disk. A dirty page may be in use if a database cursor created by an 8421** active SQL statement is reading from it, or if it is page 1 of a database 8422** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 8423** interface flushes caches for all schemas - "main", "temp", and 8424** any [attached] databases. 8425** 8426** ^If this function needs to obtain extra database locks before dirty pages 8427** can be flushed to disk, it does so. ^If those locks cannot be obtained 8428** immediately and there is a busy-handler callback configured, it is invoked 8429** in the usual manner. ^If the required lock still cannot be obtained, then 8430** the database is skipped and an attempt made to flush any dirty pages 8431** belonging to the next (if any) database. ^If any databases are skipped 8432** because locks cannot be obtained, but no other error occurs, this 8433** function returns SQLITE_BUSY. 8434** 8435** ^If any other error occurs while flushing dirty pages to disk (for 8436** example an IO error or out-of-memory condition), then processing is 8437** abandoned and an SQLite [error code] is returned to the caller immediately. 8438** 8439** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 8440** 8441** ^This function does not set the database handle error code or message 8442** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 8443*/ 8444int sqlite3_db_cacheflush(sqlite3*); 8445 8446/* 8447** CAPI3REF: The pre-update hook. 8448** 8449** ^These interfaces are only available if SQLite is compiled using the 8450** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 8451** 8452** ^The [sqlite3_preupdate_hook()] interface registers a callback function 8453** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 8454** on a database table. 8455** ^At most one preupdate hook may be registered at a time on a single 8456** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 8457** the previous setting. 8458** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 8459** with a NULL pointer as the second parameter. 8460** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 8461** the first parameter to callbacks. 8462** 8463** ^The preupdate hook only fires for changes to real database tables; the 8464** preupdate hook is not invoked for changes to [virtual tables] or to 8465** system tables like sqlite_master or sqlite_stat1. 8466** 8467** ^The second parameter to the preupdate callback is a pointer to 8468** the [database connection] that registered the preupdate hook. 8469** ^The third parameter to the preupdate callback is one of the constants 8470** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 8471** kind of update operation that is about to occur. 8472** ^(The fourth parameter to the preupdate callback is the name of the 8473** database within the database connection that is being modified. This 8474** will be "main" for the main database or "temp" for TEMP tables or 8475** the name given after the AS keyword in the [ATTACH] statement for attached 8476** databases.)^ 8477** ^The fifth parameter to the preupdate callback is the name of the 8478** table that is being modified. 8479** 8480** For an UPDATE or DELETE operation on a [rowid table], the sixth 8481** parameter passed to the preupdate callback is the initial [rowid] of the 8482** row being modified or deleted. For an INSERT operation on a rowid table, 8483** or any operation on a WITHOUT ROWID table, the value of the sixth 8484** parameter is undefined. For an INSERT or UPDATE on a rowid table the 8485** seventh parameter is the final rowid value of the row being inserted 8486** or updated. The value of the seventh parameter passed to the callback 8487** function is not defined for operations on WITHOUT ROWID tables, or for 8488** INSERT operations on rowid tables. 8489** 8490** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 8491** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 8492** provide additional information about a preupdate event. These routines 8493** may only be called from within a preupdate callback. Invoking any of 8494** these routines from outside of a preupdate callback or with a 8495** [database connection] pointer that is different from the one supplied 8496** to the preupdate callback results in undefined and probably undesirable 8497** behavior. 8498** 8499** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 8500** in the row that is being inserted, updated, or deleted. 8501** 8502** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 8503** a [protected sqlite3_value] that contains the value of the Nth column of 8504** the table row before it is updated. The N parameter must be between 0 8505** and one less than the number of columns or the behavior will be 8506** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 8507** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 8508** behavior is undefined. The [sqlite3_value] that P points to 8509** will be destroyed when the preupdate callback returns. 8510** 8511** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 8512** a [protected sqlite3_value] that contains the value of the Nth column of 8513** the table row after it is updated. The N parameter must be between 0 8514** and one less than the number of columns or the behavior will be 8515** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 8516** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 8517** behavior is undefined. The [sqlite3_value] that P points to 8518** will be destroyed when the preupdate callback returns. 8519** 8520** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 8521** callback was invoked as a result of a direct insert, update, or delete 8522** operation; or 1 for inserts, updates, or deletes invoked by top-level 8523** triggers; or 2 for changes resulting from triggers called by top-level 8524** triggers; and so forth. 8525** 8526** See also: [sqlite3_update_hook()] 8527*/ 8528#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 8529void *sqlite3_preupdate_hook( 8530 sqlite3 *db, 8531 void(*xPreUpdate)( 8532 void *pCtx, /* Copy of third arg to preupdate_hook() */ 8533 sqlite3 *db, /* Database handle */ 8534 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 8535 char const *zDb, /* Database name */ 8536 char const *zName, /* Table name */ 8537 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 8538 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 8539 ), 8540 void* 8541); 8542int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 8543int sqlite3_preupdate_count(sqlite3 *); 8544int sqlite3_preupdate_depth(sqlite3 *); 8545int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 8546#endif 8547 8548/* 8549** CAPI3REF: Low-level system error code 8550** 8551** ^Attempt to return the underlying operating system error code or error 8552** number that caused the most recent I/O error or failure to open a file. 8553** The return value is OS-dependent. For example, on unix systems, after 8554** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 8555** called to get back the underlying "errno" that caused the problem, such 8556** as ENOSPC, EAUTH, EISDIR, and so forth. 8557*/ 8558int sqlite3_system_errno(sqlite3*); 8559 8560/* 8561** CAPI3REF: Database Snapshot 8562** KEYWORDS: {snapshot} {sqlite3_snapshot} 8563** EXPERIMENTAL 8564** 8565** An instance of the snapshot object records the state of a [WAL mode] 8566** database for some specific point in history. 8567** 8568** In [WAL mode], multiple [database connections] that are open on the 8569** same database file can each be reading a different historical version 8570** of the database file. When a [database connection] begins a read 8571** transaction, that connection sees an unchanging copy of the database 8572** as it existed for the point in time when the transaction first started. 8573** Subsequent changes to the database from other connections are not seen 8574** by the reader until a new read transaction is started. 8575** 8576** The sqlite3_snapshot object records state information about an historical 8577** version of the database file so that it is possible to later open a new read 8578** transaction that sees that historical version of the database rather than 8579** the most recent version. 8580** 8581** The constructor for this object is [sqlite3_snapshot_get()]. The 8582** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer 8583** to an historical snapshot (if possible). The destructor for 8584** sqlite3_snapshot objects is [sqlite3_snapshot_free()]. 8585*/ 8586typedef struct sqlite3_snapshot { 8587 unsigned char hidden[48]; 8588} sqlite3_snapshot; 8589 8590/* 8591** CAPI3REF: Record A Database Snapshot 8592** EXPERIMENTAL 8593** 8594** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 8595** new [sqlite3_snapshot] object that records the current state of 8596** schema S in database connection D. ^On success, the 8597** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 8598** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 8599** If there is not already a read-transaction open on schema S when 8600** this function is called, one is opened automatically. 8601** 8602** The following must be true for this function to succeed. If any of 8603** the following statements are false when sqlite3_snapshot_get() is 8604** called, SQLITE_ERROR is returned. The final value of *P is undefined 8605** in this case. 8606** 8607** <ul> 8608** <li> The database handle must be in [autocommit mode]. 8609** 8610** <li> Schema S of [database connection] D must be a [WAL mode] database. 8611** 8612** <li> There must not be a write transaction open on schema S of database 8613** connection D. 8614** 8615** <li> One or more transactions must have been written to the current wal 8616** file since it was created on disk (by any connection). This means 8617** that a snapshot cannot be taken on a wal mode database with no wal 8618** file immediately after it is first opened. At least one transaction 8619** must be written to it first. 8620** </ul> 8621** 8622** This function may also return SQLITE_NOMEM. If it is called with the 8623** database handle in autocommit mode but fails for some other reason, 8624** whether or not a read transaction is opened on schema S is undefined. 8625** 8626** The [sqlite3_snapshot] object returned from a successful call to 8627** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 8628** to avoid a memory leak. 8629** 8630** The [sqlite3_snapshot_get()] interface is only available when the 8631** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8632*/ 8633SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 8634 sqlite3 *db, 8635 const char *zSchema, 8636 sqlite3_snapshot **ppSnapshot 8637); 8638 8639/* 8640** CAPI3REF: Start a read transaction on an historical snapshot 8641** EXPERIMENTAL 8642** 8643** ^The [sqlite3_snapshot_open(D,S,P)] interface starts a 8644** read transaction for schema S of 8645** [database connection] D such that the read transaction 8646** refers to historical [snapshot] P, rather than the most 8647** recent change to the database. 8648** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success 8649** or an appropriate [error code] if it fails. 8650** 8651** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be 8652** the first operation following the [BEGIN] that takes the schema S 8653** out of [autocommit mode]. 8654** ^In other words, schema S must not currently be in 8655** a transaction for [sqlite3_snapshot_open(D,S,P)] to work, but the 8656** database connection D must be out of [autocommit mode]. 8657** ^A [snapshot] will fail to open if it has been overwritten by a 8658** [checkpoint]. 8659** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 8660** database connection D does not know that the database file for 8661** schema S is in [WAL mode]. A database connection might not know 8662** that the database file is in [WAL mode] if there has been no prior 8663** I/O on that database connection, or if the database entered [WAL mode] 8664** after the most recent I/O on the database connection.)^ 8665** (Hint: Run "[PRAGMA application_id]" against a newly opened 8666** database connection in order to make it ready to use snapshots.) 8667** 8668** The [sqlite3_snapshot_open()] interface is only available when the 8669** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8670*/ 8671SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 8672 sqlite3 *db, 8673 const char *zSchema, 8674 sqlite3_snapshot *pSnapshot 8675); 8676 8677/* 8678** CAPI3REF: Destroy a snapshot 8679** EXPERIMENTAL 8680** 8681** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 8682** The application must eventually free every [sqlite3_snapshot] object 8683** using this routine to avoid a memory leak. 8684** 8685** The [sqlite3_snapshot_free()] interface is only available when the 8686** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8687*/ 8688SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 8689 8690/* 8691** CAPI3REF: Compare the ages of two snapshot handles. 8692** EXPERIMENTAL 8693** 8694** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 8695** of two valid snapshot handles. 8696** 8697** If the two snapshot handles are not associated with the same database 8698** file, the result of the comparison is undefined. 8699** 8700** Additionally, the result of the comparison is only valid if both of the 8701** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 8702** last time the wal file was deleted. The wal file is deleted when the 8703** database is changed back to rollback mode or when the number of database 8704** clients drops to zero. If either snapshot handle was obtained before the 8705** wal file was last deleted, the value returned by this function 8706** is undefined. 8707** 8708** Otherwise, this API returns a negative value if P1 refers to an older 8709** snapshot than P2, zero if the two handles refer to the same database 8710** snapshot, and a positive value if P1 is a newer snapshot than P2. 8711*/ 8712SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 8713 sqlite3_snapshot *p1, 8714 sqlite3_snapshot *p2 8715); 8716 8717/* 8718** CAPI3REF: Recover snapshots from a wal file 8719** EXPERIMENTAL 8720** 8721** If all connections disconnect from a database file but do not perform 8722** a checkpoint, the existing wal file is opened along with the database 8723** file the next time the database is opened. At this point it is only 8724** possible to successfully call sqlite3_snapshot_open() to open the most 8725** recent snapshot of the database (the one at the head of the wal file), 8726** even though the wal file may contain other valid snapshots for which 8727** clients have sqlite3_snapshot handles. 8728** 8729** This function attempts to scan the wal file associated with database zDb 8730** of database handle db and make all valid snapshots available to 8731** sqlite3_snapshot_open(). It is an error if there is already a read 8732** transaction open on the database, or if the database is not a wal mode 8733** database. 8734** 8735** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 8736*/ 8737SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 8738 8739/* 8740** Undo the hack that converts floating point types to integer for 8741** builds on processors without floating point support. 8742*/ 8743#ifdef SQLITE_OMIT_FLOATING_POINT 8744# undef double 8745#endif 8746 8747#ifdef __cplusplus 8748} /* End of the 'extern "C"' block */ 8749#endif 8750#endif /* SQLITE3_H */ 8751