1/* 2** 2001 September 15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are supposed to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef SQLITE3_H 34#define SQLITE3_H 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Provide the ability to override linkage features of the interface. 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51#ifndef SQLITE_API 52# define SQLITE_API 53#endif 54#ifndef SQLITE_CDECL 55# define SQLITE_CDECL 56#endif 57#ifndef SQLITE_APICALL 58# define SQLITE_APICALL 59#endif 60#ifndef SQLITE_STDCALL 61# define SQLITE_STDCALL SQLITE_APICALL 62#endif 63#ifndef SQLITE_CALLBACK 64# define SQLITE_CALLBACK 65#endif 66#ifndef SQLITE_SYSAPI 67# define SQLITE_SYSAPI 68#endif 69 70/* 71** These no-op macros are used in front of interfaces to mark those 72** interfaces as either deprecated or experimental. New applications 73** should not use deprecated interfaces - they are supported for backwards 74** compatibility only. Application writers should be aware that 75** experimental interfaces are subject to change in point releases. 76** 77** These macros used to resolve to various kinds of compiler magic that 78** would generate warning messages when they were used. But that 79** compiler magic ended up generating such a flurry of bug reports 80** that we have taken it all out and gone back to using simple 81** noop macros. 82*/ 83#define SQLITE_DEPRECATED 84#define SQLITE_EXPERIMENTAL 85 86/* 87** Ensure these symbols were not defined by some previous header file. 88*/ 89#ifdef SQLITE_VERSION 90# undef SQLITE_VERSION 91#endif 92#ifdef SQLITE_VERSION_NUMBER 93# undef SQLITE_VERSION_NUMBER 94#endif 95 96/* 97** CAPI3REF: Compile-Time Library Version Numbers 98** 99** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 100** evaluates to a string literal that is the SQLite version in the 101** format "X.Y.Z" where X is the major version number (always 3 for 102** SQLite3) and Y is the minor version number and Z is the release number.)^ 103** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 104** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 105** numbers used in [SQLITE_VERSION].)^ 106** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 107** be larger than the release from which it is derived. Either Y will 108** be held constant and Z will be incremented or else Y will be incremented 109** and Z will be reset to zero. 110** 111** Since [version 3.6.18] ([dateof:3.6.18]), 112** SQLite source code has been stored in the 113** <a href="http://www.fossil-scm.org/">Fossil configuration management 114** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 115** a string which identifies a particular check-in of SQLite 116** within its configuration management system. ^The SQLITE_SOURCE_ID 117** string contains the date and time of the check-in (UTC) and 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 /* SQL error or missing database */ 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 /* Database is empty */ 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 /* Auxiliary database format error */ 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_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 498#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 499#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 500#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 501#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 502#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 503#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 504#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 505#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 506#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 507#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 508#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 509#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 510#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 511#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 512#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 513#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 514#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 515#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 516#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 517#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 518#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 519#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 520#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 521#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 522#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 523#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 524#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8)) 525 526/* 527** CAPI3REF: Flags For File Open Operations 528** 529** These bit values are intended for use in the 530** 3rd parameter to the [sqlite3_open_v2()] interface and 531** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 532*/ 533#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 534#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 535#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 536#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 537#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 538#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 539#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 540#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 541#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 542#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 543#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 544#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 545#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 546#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 547#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 548#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 549#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 550#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 551#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 552#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 553 554/* Reserved: 0x00F00000 */ 555 556/* 557** CAPI3REF: Device Characteristics 558** 559** The xDeviceCharacteristics method of the [sqlite3_io_methods] 560** object returns an integer which is a vector of these 561** bit values expressing I/O characteristics of the mass storage 562** device that holds the file that the [sqlite3_io_methods] 563** refers to. 564** 565** The SQLITE_IOCAP_ATOMIC property means that all writes of 566** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 567** mean that writes of blocks that are nnn bytes in size and 568** are aligned to an address which is an integer multiple of 569** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 570** that when data is appended to a file, the data is appended 571** first then the size of the file is extended, never the other 572** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 573** information is written to disk in the same order as calls 574** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 575** after reboot following a crash or power loss, the only bytes in a 576** file that were written at the application level might have changed 577** and that adjacent bytes, even bytes within the same sector are 578** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 579** flag indicates that a file cannot be deleted when open. The 580** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 581** read-only media and cannot be changed even by processes with 582** elevated privileges. 583*/ 584#define SQLITE_IOCAP_ATOMIC 0x00000001 585#define SQLITE_IOCAP_ATOMIC512 0x00000002 586#define SQLITE_IOCAP_ATOMIC1K 0x00000004 587#define SQLITE_IOCAP_ATOMIC2K 0x00000008 588#define SQLITE_IOCAP_ATOMIC4K 0x00000010 589#define SQLITE_IOCAP_ATOMIC8K 0x00000020 590#define SQLITE_IOCAP_ATOMIC16K 0x00000040 591#define SQLITE_IOCAP_ATOMIC32K 0x00000080 592#define SQLITE_IOCAP_ATOMIC64K 0x00000100 593#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 594#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 595#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 596#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 597#define SQLITE_IOCAP_IMMUTABLE 0x00002000 598 599/* 600** CAPI3REF: File Locking Levels 601** 602** SQLite uses one of these integer values as the second 603** argument to calls it makes to the xLock() and xUnlock() methods 604** of an [sqlite3_io_methods] object. 605*/ 606#define SQLITE_LOCK_NONE 0 607#define SQLITE_LOCK_SHARED 1 608#define SQLITE_LOCK_RESERVED 2 609#define SQLITE_LOCK_PENDING 3 610#define SQLITE_LOCK_EXCLUSIVE 4 611 612/* 613** CAPI3REF: Synchronization Type Flags 614** 615** When SQLite invokes the xSync() method of an 616** [sqlite3_io_methods] object it uses a combination of 617** these integer values as the second argument. 618** 619** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 620** sync operation only needs to flush data to mass storage. Inode 621** information need not be flushed. If the lower four bits of the flag 622** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 623** If the lower four bits equal SQLITE_SYNC_FULL, that means 624** to use Mac OS X style fullsync instead of fsync(). 625** 626** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 627** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 628** settings. The [synchronous pragma] determines when calls to the 629** xSync VFS method occur and applies uniformly across all platforms. 630** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 631** energetic or rigorous or forceful the sync operations are and 632** only make a difference on Mac OSX for the default SQLite code. 633** (Third-party VFS implementations might also make the distinction 634** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 635** operating systems natively supported by SQLite, only Mac OSX 636** cares about the difference.) 637*/ 638#define SQLITE_SYNC_NORMAL 0x00002 639#define SQLITE_SYNC_FULL 0x00003 640#define SQLITE_SYNC_DATAONLY 0x00010 641 642/* 643** CAPI3REF: OS Interface Open File Handle 644** 645** An [sqlite3_file] object represents an open file in the 646** [sqlite3_vfs | OS interface layer]. Individual OS interface 647** implementations will 648** want to subclass this object by appending additional fields 649** for their own use. The pMethods entry is a pointer to an 650** [sqlite3_io_methods] object that defines methods for performing 651** I/O operations on the open file. 652*/ 653typedef struct sqlite3_file sqlite3_file; 654struct sqlite3_file { 655 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 656}; 657 658/* 659** CAPI3REF: OS Interface File Virtual Methods Object 660** 661** Every file opened by the [sqlite3_vfs.xOpen] method populates an 662** [sqlite3_file] object (or, more commonly, a subclass of the 663** [sqlite3_file] object) with a pointer to an instance of this object. 664** This object defines the methods used to perform various operations 665** against the open file represented by the [sqlite3_file] object. 666** 667** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 668** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 669** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 670** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 671** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 672** to NULL. 673** 674** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 675** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 676** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 677** flag may be ORed in to indicate that only the data of the file 678** and not its inode needs to be synced. 679** 680** The integer values to xLock() and xUnlock() are one of 681** <ul> 682** <li> [SQLITE_LOCK_NONE], 683** <li> [SQLITE_LOCK_SHARED], 684** <li> [SQLITE_LOCK_RESERVED], 685** <li> [SQLITE_LOCK_PENDING], or 686** <li> [SQLITE_LOCK_EXCLUSIVE]. 687** </ul> 688** xLock() increases the lock. xUnlock() decreases the lock. 689** The xCheckReservedLock() method checks whether any database connection, 690** either in this process or in some other process, is holding a RESERVED, 691** PENDING, or EXCLUSIVE lock on the file. It returns true 692** if such a lock exists and false otherwise. 693** 694** The xFileControl() method is a generic interface that allows custom 695** VFS implementations to directly control an open file using the 696** [sqlite3_file_control()] interface. The second "op" argument is an 697** integer opcode. The third argument is a generic pointer intended to 698** point to a structure that may contain arguments or space in which to 699** write return values. Potential uses for xFileControl() might be 700** functions to enable blocking locks with timeouts, to change the 701** locking strategy (for example to use dot-file locks), to inquire 702** about the status of a lock, or to break stale locks. The SQLite 703** core reserves all opcodes less than 100 for its own use. 704** A [file control opcodes | list of opcodes] less than 100 is available. 705** Applications that define a custom xFileControl method should use opcodes 706** greater than 100 to avoid conflicts. VFS implementations should 707** return [SQLITE_NOTFOUND] for file control opcodes that they do not 708** recognize. 709** 710** The xSectorSize() method returns the sector size of the 711** device that underlies the file. The sector size is the 712** minimum write that can be performed without disturbing 713** other bytes in the file. The xDeviceCharacteristics() 714** method returns a bit vector describing behaviors of the 715** underlying device: 716** 717** <ul> 718** <li> [SQLITE_IOCAP_ATOMIC] 719** <li> [SQLITE_IOCAP_ATOMIC512] 720** <li> [SQLITE_IOCAP_ATOMIC1K] 721** <li> [SQLITE_IOCAP_ATOMIC2K] 722** <li> [SQLITE_IOCAP_ATOMIC4K] 723** <li> [SQLITE_IOCAP_ATOMIC8K] 724** <li> [SQLITE_IOCAP_ATOMIC16K] 725** <li> [SQLITE_IOCAP_ATOMIC32K] 726** <li> [SQLITE_IOCAP_ATOMIC64K] 727** <li> [SQLITE_IOCAP_SAFE_APPEND] 728** <li> [SQLITE_IOCAP_SEQUENTIAL] 729** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN] 730** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE] 731** <li> [SQLITE_IOCAP_IMMUTABLE] 732** </ul> 733** 734** The SQLITE_IOCAP_ATOMIC property means that all writes of 735** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 736** mean that writes of blocks that are nnn bytes in size and 737** are aligned to an address which is an integer multiple of 738** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 739** that when data is appended to a file, the data is appended 740** first then the size of the file is extended, never the other 741** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 742** information is written to disk in the same order as calls 743** to xWrite(). 744** 745** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 746** in the unread portions of the buffer with zeros. A VFS that 747** fails to zero-fill short reads might seem to work. However, 748** failure to zero-fill short reads will eventually lead to 749** database corruption. 750*/ 751typedef struct sqlite3_io_methods sqlite3_io_methods; 752struct sqlite3_io_methods { 753 int iVersion; 754 int (*xClose)(sqlite3_file*); 755 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 756 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 757 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 758 int (*xSync)(sqlite3_file*, int flags); 759 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 760 int (*xLock)(sqlite3_file*, int); 761 int (*xUnlock)(sqlite3_file*, int); 762 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 763 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 764 int (*xSectorSize)(sqlite3_file*); 765 int (*xDeviceCharacteristics)(sqlite3_file*); 766 /* Methods above are valid for version 1 */ 767 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 768 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 769 void (*xShmBarrier)(sqlite3_file*); 770 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 771 /* Methods above are valid for version 2 */ 772 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 773 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 774 /* Methods above are valid for version 3 */ 775 /* Additional methods may be added in future releases */ 776}; 777 778/* 779** CAPI3REF: Standard File Control Opcodes 780** KEYWORDS: {file control opcodes} {file control opcode} 781** 782** These integer constants are opcodes for the xFileControl method 783** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 784** interface. 785** 786** <ul> 787** <li>[[SQLITE_FCNTL_LOCKSTATE]] 788** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 789** opcode causes the xFileControl method to write the current state of 790** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 791** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 792** into an integer that the pArg argument points to. This capability 793** is used during testing and is only available when the SQLITE_TEST 794** compile-time option is used. 795** 796** <li>[[SQLITE_FCNTL_SIZE_HINT]] 797** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 798** layer a hint of how large the database file will grow to be during the 799** current transaction. This hint is not guaranteed to be accurate but it 800** is often close. The underlying VFS might choose to preallocate database 801** file space based on this hint in order to help writes to the database 802** file run faster. 803** 804** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 805** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 806** extends and truncates the database file in chunks of a size specified 807** by the user. The fourth argument to [sqlite3_file_control()] should 808** point to an integer (type int) containing the new chunk-size to use 809** for the nominated database. Allocating database file space in large 810** chunks (say 1MB at a time), may reduce file-system fragmentation and 811** improve performance on some systems. 812** 813** <li>[[SQLITE_FCNTL_FILE_POINTER]] 814** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 815** to the [sqlite3_file] object associated with a particular database 816** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER]. 817** 818** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]] 819** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer 820** to the [sqlite3_file] object associated with the journal file (either 821** the [rollback journal] or the [write-ahead log]) for a particular database 822** connection. See also [SQLITE_FCNTL_FILE_POINTER]. 823** 824** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 825** No longer in use. 826** 827** <li>[[SQLITE_FCNTL_SYNC]] 828** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 829** sent to the VFS immediately before the xSync method is invoked on a 830** database file descriptor. Or, if the xSync method is not invoked 831** because the user has configured SQLite with 832** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 833** of the xSync method. In most cases, the pointer argument passed with 834** this file-control is NULL. However, if the database file is being synced 835** as part of a multi-database commit, the argument points to a nul-terminated 836** string containing the transactions master-journal file name. VFSes that 837** do not need this signal should silently ignore this opcode. Applications 838** should not call [sqlite3_file_control()] with this opcode as doing so may 839** disrupt the operation of the specialized VFSes that do require it. 840** 841** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 842** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 843** and sent to the VFS after a transaction has been committed immediately 844** but before the database is unlocked. VFSes that do not need this signal 845** should silently ignore this opcode. Applications should not call 846** [sqlite3_file_control()] with this opcode as doing so may disrupt the 847** operation of the specialized VFSes that do require it. 848** 849** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 850** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 851** retry counts and intervals for certain disk I/O operations for the 852** windows [VFS] in order to provide robustness in the presence of 853** anti-virus programs. By default, the windows VFS will retry file read, 854** file write, and file delete operations up to 10 times, with a delay 855** of 25 milliseconds before the first retry and with the delay increasing 856** by an additional 25 milliseconds with each subsequent retry. This 857** opcode allows these two values (10 retries and 25 milliseconds of delay) 858** to be adjusted. The values are changed for all database connections 859** within the same process. The argument is a pointer to an array of two 860** integers where the first integer is the new retry count and the second 861** integer is the delay. If either integer is negative, then the setting 862** is not changed but instead the prior value of that setting is written 863** into the array entry, allowing the current retry settings to be 864** interrogated. The zDbName parameter is ignored. 865** 866** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 867** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 868** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 869** write ahead log and shared memory files used for transaction control 870** are automatically deleted when the latest connection to the database 871** closes. Setting persistent WAL mode causes those files to persist after 872** close. Persisting the files is useful when other processes that do not 873** have write permission on the directory containing the database file want 874** to read the database file, as the WAL and shared memory files must exist 875** in order for the database to be readable. The fourth parameter to 876** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 877** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 878** WAL mode. If the integer is -1, then it is overwritten with the current 879** WAL persistence setting. 880** 881** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 882** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 883** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 884** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 885** xDeviceCharacteristics methods. 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 zero-damage mode or 1 to enable zero-damage 888** mode. If the integer is -1, then it is overwritten with the current 889** zero-damage mode setting. 890** 891** <li>[[SQLITE_FCNTL_OVERWRITE]] 892** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 893** a write transaction to indicate that, unless it is rolled back for some 894** reason, the entire database file will be overwritten by the current 895** transaction. This is used by VACUUM operations. 896** 897** <li>[[SQLITE_FCNTL_VFSNAME]] 898** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 899** all [VFSes] in the VFS stack. The names are of all VFS shims and the 900** final bottom-level VFS are written into memory obtained from 901** [sqlite3_malloc()] and the result is stored in the char* variable 902** that the fourth parameter of [sqlite3_file_control()] points to. 903** The caller is responsible for freeing the memory when done. As with 904** all file-control actions, there is no guarantee that this will actually 905** do anything. Callers should initialize the char* variable to a NULL 906** pointer in case this file-control is not implemented. This file-control 907** is intended for diagnostic use only. 908** 909** <li>[[SQLITE_FCNTL_VFS_POINTER]] 910** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 911** [VFSes] currently in use. ^(The argument X in 912** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 913** of type "[sqlite3_vfs] **". This opcodes will set *X 914** to a pointer to the top-level VFS.)^ 915** ^When there are multiple VFS shims in the stack, this opcode finds the 916** upper-most shim only. 917** 918** <li>[[SQLITE_FCNTL_PRAGMA]] 919** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 920** file control is sent to the open [sqlite3_file] object corresponding 921** to the database file to which the pragma statement refers. ^The argument 922** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 923** pointers to strings (char**) in which the second element of the array 924** is the name of the pragma and the third element is the argument to the 925** pragma or NULL if the pragma has no argument. ^The handler for an 926** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 927** of the char** argument point to a string obtained from [sqlite3_mprintf()] 928** or the equivalent and that string will become the result of the pragma or 929** the error message if the pragma fails. ^If the 930** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 931** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 932** file control returns [SQLITE_OK], then the parser assumes that the 933** VFS has handled the PRAGMA itself and the parser generates a no-op 934** prepared statement if result string is NULL, or that returns a copy 935** of the result string if the string is non-NULL. 936** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 937** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 938** that the VFS encountered an error while handling the [PRAGMA] and the 939** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 940** file control occurs at the beginning of pragma statement analysis and so 941** it is able to override built-in [PRAGMA] statements. 942** 943** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 944** ^The [SQLITE_FCNTL_BUSYHANDLER] 945** file-control may be invoked by SQLite on the database file handle 946** shortly after it is opened in order to provide a custom VFS with access 947** to the connections busy-handler callback. The argument is of type (void **) 948** - an array of two (void *) values. The first (void *) actually points 949** to a function of type (int (*)(void *)). In order to invoke the connections 950** busy-handler, this function should be invoked with the second (void *) in 951** the array as the only argument. If it returns non-zero, then the operation 952** should be retried. If it returns zero, the custom VFS should abandon the 953** current operation. 954** 955** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 956** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 957** to have SQLite generate a 958** temporary filename using the same algorithm that is followed to generate 959** temporary filenames for TEMP tables and other internal uses. The 960** argument should be a char** which will be filled with the filename 961** written into memory obtained from [sqlite3_malloc()]. The caller should 962** invoke [sqlite3_free()] on the result to avoid a memory leak. 963** 964** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 965** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 966** maximum number of bytes that will be used for memory-mapped I/O. 967** The argument is a pointer to a value of type sqlite3_int64 that 968** is an advisory maximum number of bytes in the file to memory map. The 969** pointer is overwritten with the old value. The limit is not changed if 970** the value originally pointed to is negative, and so the current limit 971** can be queried by passing in a pointer to a negative number. This 972** file-control is used internally to implement [PRAGMA mmap_size]. 973** 974** <li>[[SQLITE_FCNTL_TRACE]] 975** The [SQLITE_FCNTL_TRACE] file control provides advisory information 976** to the VFS about what the higher layers of the SQLite stack are doing. 977** This file control is used by some VFS activity tracing [shims]. 978** The argument is a zero-terminated string. Higher layers in the 979** SQLite stack may generate instances of this file control if 980** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 981** 982** <li>[[SQLITE_FCNTL_HAS_MOVED]] 983** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 984** pointer to an integer and it writes a boolean into that integer depending 985** on whether or not the file has been renamed, moved, or deleted since it 986** was first opened. 987** 988** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]] 989** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the 990** underlying native file handle associated with a file handle. This file 991** control interprets its argument as a pointer to a native file handle and 992** writes the resulting value there. 993** 994** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 995** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 996** opcode causes the xFileControl method to swap the file handle with the one 997** pointed to by the pArg argument. This capability is used during testing 998** and only needs to be supported when SQLITE_TEST is defined. 999** 1000** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 1001** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 1002** be advantageous to block on the next WAL lock if the lock is not immediately 1003** available. The WAL subsystem issues this signal during rare 1004** circumstances in order to fix a problem with priority inversion. 1005** Applications should <em>not</em> use this file-control. 1006** 1007** <li>[[SQLITE_FCNTL_ZIPVFS]] 1008** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 1009** VFS should return SQLITE_NOTFOUND for this opcode. 1010** 1011** <li>[[SQLITE_FCNTL_RBU]] 1012** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 1013** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 1014** this opcode. 1015** </ul> 1016*/ 1017#define SQLITE_FCNTL_LOCKSTATE 1 1018#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1019#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1020#define SQLITE_FCNTL_LAST_ERRNO 4 1021#define SQLITE_FCNTL_SIZE_HINT 5 1022#define SQLITE_FCNTL_CHUNK_SIZE 6 1023#define SQLITE_FCNTL_FILE_POINTER 7 1024#define SQLITE_FCNTL_SYNC_OMITTED 8 1025#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1026#define SQLITE_FCNTL_PERSIST_WAL 10 1027#define SQLITE_FCNTL_OVERWRITE 11 1028#define SQLITE_FCNTL_VFSNAME 12 1029#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1030#define SQLITE_FCNTL_PRAGMA 14 1031#define SQLITE_FCNTL_BUSYHANDLER 15 1032#define SQLITE_FCNTL_TEMPFILENAME 16 1033#define SQLITE_FCNTL_MMAP_SIZE 18 1034#define SQLITE_FCNTL_TRACE 19 1035#define SQLITE_FCNTL_HAS_MOVED 20 1036#define SQLITE_FCNTL_SYNC 21 1037#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1038#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1039#define SQLITE_FCNTL_WAL_BLOCK 24 1040#define SQLITE_FCNTL_ZIPVFS 25 1041#define SQLITE_FCNTL_RBU 26 1042#define SQLITE_FCNTL_VFS_POINTER 27 1043#define SQLITE_FCNTL_JOURNAL_POINTER 28 1044#define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1045#define SQLITE_FCNTL_PDB 30 1046 1047/* deprecated names */ 1048#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1049#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1050#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1051 1052 1053/* 1054** CAPI3REF: Mutex Handle 1055** 1056** The mutex module within SQLite defines [sqlite3_mutex] to be an 1057** abstract type for a mutex object. The SQLite core never looks 1058** at the internal representation of an [sqlite3_mutex]. It only 1059** deals with pointers to the [sqlite3_mutex] object. 1060** 1061** Mutexes are created using [sqlite3_mutex_alloc()]. 1062*/ 1063typedef struct sqlite3_mutex sqlite3_mutex; 1064 1065/* 1066** CAPI3REF: Loadable Extension Thunk 1067** 1068** A pointer to the opaque sqlite3_api_routines structure is passed as 1069** the third parameter to entry points of [loadable extensions]. This 1070** structure must be typedefed in order to work around compiler warnings 1071** on some platforms. 1072*/ 1073typedef struct sqlite3_api_routines sqlite3_api_routines; 1074 1075/* 1076** CAPI3REF: OS Interface Object 1077** 1078** An instance of the sqlite3_vfs object defines the interface between 1079** the SQLite core and the underlying operating system. The "vfs" 1080** in the name of the object stands for "virtual file system". See 1081** the [VFS | VFS documentation] for further information. 1082** 1083** The value of the iVersion field is initially 1 but may be larger in 1084** future versions of SQLite. Additional fields may be appended to this 1085** object when the iVersion value is increased. Note that the structure 1086** of the sqlite3_vfs object changes in the transaction between 1087** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 1088** modified. 1089** 1090** The szOsFile field is the size of the subclassed [sqlite3_file] 1091** structure used by this VFS. mxPathname is the maximum length of 1092** a pathname in this VFS. 1093** 1094** Registered sqlite3_vfs objects are kept on a linked list formed by 1095** the pNext pointer. The [sqlite3_vfs_register()] 1096** and [sqlite3_vfs_unregister()] interfaces manage this list 1097** in a thread-safe way. The [sqlite3_vfs_find()] interface 1098** searches the list. Neither the application code nor the VFS 1099** implementation should use the pNext pointer. 1100** 1101** The pNext field is the only field in the sqlite3_vfs 1102** structure that SQLite will ever modify. SQLite will only access 1103** or modify this field while holding a particular static mutex. 1104** The application should never modify anything within the sqlite3_vfs 1105** object once the object has been registered. 1106** 1107** The zName field holds the name of the VFS module. The name must 1108** be unique across all VFS modules. 1109** 1110** [[sqlite3_vfs.xOpen]] 1111** ^SQLite guarantees that the zFilename parameter to xOpen 1112** is either a NULL pointer or string obtained 1113** from xFullPathname() with an optional suffix added. 1114** ^If a suffix is added to the zFilename parameter, it will 1115** consist of a single "-" character followed by no more than 1116** 11 alphanumeric and/or "-" characters. 1117** ^SQLite further guarantees that 1118** the string will be valid and unchanged until xClose() is 1119** called. Because of the previous sentence, 1120** the [sqlite3_file] can safely store a pointer to the 1121** filename if it needs to remember the filename for some reason. 1122** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1123** must invent its own temporary name for the file. ^Whenever the 1124** xFilename parameter is NULL it will also be the case that the 1125** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1126** 1127** The flags argument to xOpen() includes all bits set in 1128** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1129** or [sqlite3_open16()] is used, then flags includes at least 1130** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1131** If xOpen() opens a file read-only then it sets *pOutFlags to 1132** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1133** 1134** ^(SQLite will also add one of the following flags to the xOpen() 1135** call, depending on the object being opened: 1136** 1137** <ul> 1138** <li> [SQLITE_OPEN_MAIN_DB] 1139** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1140** <li> [SQLITE_OPEN_TEMP_DB] 1141** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1142** <li> [SQLITE_OPEN_TRANSIENT_DB] 1143** <li> [SQLITE_OPEN_SUBJOURNAL] 1144** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1145** <li> [SQLITE_OPEN_WAL] 1146** </ul>)^ 1147** 1148** The file I/O implementation can use the object type flags to 1149** change the way it deals with files. For example, an application 1150** that does not care about crash recovery or rollback might make 1151** the open of a journal file a no-op. Writes to this journal would 1152** also be no-ops, and any attempt to read the journal would return 1153** SQLITE_IOERR. Or the implementation might recognize that a database 1154** file will be doing page-aligned sector reads and writes in a random 1155** order and set up its I/O subsystem accordingly. 1156** 1157** SQLite might also add one of the following flags to the xOpen method: 1158** 1159** <ul> 1160** <li> [SQLITE_OPEN_DELETEONCLOSE] 1161** <li> [SQLITE_OPEN_EXCLUSIVE] 1162** </ul> 1163** 1164** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1165** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1166** will be set for TEMP databases and their journals, transient 1167** databases, and subjournals. 1168** 1169** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1170** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1171** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1172** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1173** SQLITE_OPEN_CREATE, is used to indicate that file should always 1174** be created, and that it is an error if it already exists. 1175** It is <i>not</i> used to indicate the file should be opened 1176** for exclusive access. 1177** 1178** ^At least szOsFile bytes of memory are allocated by SQLite 1179** to hold the [sqlite3_file] structure passed as the third 1180** argument to xOpen. The xOpen method does not have to 1181** allocate the structure; it should just fill it in. Note that 1182** the xOpen method must set the sqlite3_file.pMethods to either 1183** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1184** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1185** element will be valid after xOpen returns regardless of the success 1186** or failure of the xOpen call. 1187** 1188** [[sqlite3_vfs.xAccess]] 1189** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1190** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1191** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1192** to test whether a file is at least readable. The file can be a 1193** directory. 1194** 1195** ^SQLite will always allocate at least mxPathname+1 bytes for the 1196** output buffer xFullPathname. The exact size of the output buffer 1197** is also passed as a parameter to both methods. If the output buffer 1198** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1199** handled as a fatal error by SQLite, vfs implementations should endeavor 1200** to prevent this by setting mxPathname to a sufficiently large value. 1201** 1202** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1203** interfaces are not strictly a part of the filesystem, but they are 1204** included in the VFS structure for completeness. 1205** The xRandomness() function attempts to return nBytes bytes 1206** of good-quality randomness into zOut. The return value is 1207** the actual number of bytes of randomness obtained. 1208** The xSleep() method causes the calling thread to sleep for at 1209** least the number of microseconds given. ^The xCurrentTime() 1210** method returns a Julian Day Number for the current date and time as 1211** a floating point value. 1212** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1213** Day Number multiplied by 86400000 (the number of milliseconds in 1214** a 24-hour day). 1215** ^SQLite will use the xCurrentTimeInt64() method to get the current 1216** date and time if that method is available (if iVersion is 2 or 1217** greater and the function pointer is not NULL) and will fall back 1218** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1219** 1220** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1221** are not used by the SQLite core. These optional interfaces are provided 1222** by some VFSes to facilitate testing of the VFS code. By overriding 1223** system calls with functions under its control, a test program can 1224** simulate faults and error conditions that would otherwise be difficult 1225** or impossible to induce. The set of system calls that can be overridden 1226** varies from one VFS to another, and from one version of the same VFS to the 1227** next. Applications that use these interfaces must be prepared for any 1228** or all of these interfaces to be NULL or for their behavior to change 1229** from one release to the next. Applications must not attempt to access 1230** any of these methods if the iVersion of the VFS is less than 3. 1231*/ 1232typedef struct sqlite3_vfs sqlite3_vfs; 1233typedef void (*sqlite3_syscall_ptr)(void); 1234struct sqlite3_vfs { 1235 int iVersion; /* Structure version number (currently 3) */ 1236 int szOsFile; /* Size of subclassed sqlite3_file */ 1237 int mxPathname; /* Maximum file pathname length */ 1238 sqlite3_vfs *pNext; /* Next registered VFS */ 1239 const char *zName; /* Name of this virtual file system */ 1240 void *pAppData; /* Pointer to application-specific data */ 1241 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1242 int flags, int *pOutFlags); 1243 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1244 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1245 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1246 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1247 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1248 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1249 void (*xDlClose)(sqlite3_vfs*, void*); 1250 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1251 int (*xSleep)(sqlite3_vfs*, int microseconds); 1252 int (*xCurrentTime)(sqlite3_vfs*, double*); 1253 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1254 /* 1255 ** The methods above are in version 1 of the sqlite_vfs object 1256 ** definition. Those that follow are added in version 2 or later 1257 */ 1258 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1259 /* 1260 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1261 ** Those below are for version 3 and greater. 1262 */ 1263 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1264 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1265 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1266 /* 1267 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1268 ** New fields may be appended in future versions. The iVersion 1269 ** value will increment whenever this happens. 1270 */ 1271}; 1272 1273/* 1274** CAPI3REF: Flags for the xAccess VFS method 1275** 1276** These integer constants can be used as the third parameter to 1277** the xAccess method of an [sqlite3_vfs] object. They determine 1278** what kind of permissions the xAccess method is looking for. 1279** With SQLITE_ACCESS_EXISTS, the xAccess method 1280** simply checks whether the file exists. 1281** With SQLITE_ACCESS_READWRITE, the xAccess method 1282** checks whether the named directory is both readable and writable 1283** (in other words, if files can be added, removed, and renamed within 1284** the directory). 1285** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1286** [temp_store_directory pragma], though this could change in a future 1287** release of SQLite. 1288** With SQLITE_ACCESS_READ, the xAccess method 1289** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1290** currently unused, though it might be used in a future release of 1291** SQLite. 1292*/ 1293#define SQLITE_ACCESS_EXISTS 0 1294#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1295#define SQLITE_ACCESS_READ 2 /* Unused */ 1296 1297/* 1298** CAPI3REF: Flags for the xShmLock VFS method 1299** 1300** These integer constants define the various locking operations 1301** allowed by the xShmLock method of [sqlite3_io_methods]. The 1302** following are the only legal combinations of flags to the 1303** xShmLock method: 1304** 1305** <ul> 1306** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1307** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1308** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1309** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1310** </ul> 1311** 1312** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1313** was given on the corresponding lock. 1314** 1315** The xShmLock method can transition between unlocked and SHARED or 1316** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1317** and EXCLUSIVE. 1318*/ 1319#define SQLITE_SHM_UNLOCK 1 1320#define SQLITE_SHM_LOCK 2 1321#define SQLITE_SHM_SHARED 4 1322#define SQLITE_SHM_EXCLUSIVE 8 1323 1324/* 1325** CAPI3REF: Maximum xShmLock index 1326** 1327** The xShmLock method on [sqlite3_io_methods] may use values 1328** between 0 and this upper bound as its "offset" argument. 1329** The SQLite core will never attempt to acquire or release a 1330** lock outside of this range 1331*/ 1332#define SQLITE_SHM_NLOCK 8 1333 1334 1335/* 1336** CAPI3REF: Initialize The SQLite Library 1337** 1338** ^The sqlite3_initialize() routine initializes the 1339** SQLite library. ^The sqlite3_shutdown() routine 1340** deallocates any resources that were allocated by sqlite3_initialize(). 1341** These routines are designed to aid in process initialization and 1342** shutdown on embedded systems. Workstation applications using 1343** SQLite normally do not need to invoke either of these routines. 1344** 1345** A call to sqlite3_initialize() is an "effective" call if it is 1346** the first time sqlite3_initialize() is invoked during the lifetime of 1347** the process, or if it is the first time sqlite3_initialize() is invoked 1348** following a call to sqlite3_shutdown(). ^(Only an effective call 1349** of sqlite3_initialize() does any initialization. All other calls 1350** are harmless no-ops.)^ 1351** 1352** A call to sqlite3_shutdown() is an "effective" call if it is the first 1353** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1354** an effective call to sqlite3_shutdown() does any deinitialization. 1355** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1356** 1357** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1358** is not. The sqlite3_shutdown() interface must only be called from a 1359** single thread. All open [database connections] must be closed and all 1360** other SQLite resources must be deallocated prior to invoking 1361** sqlite3_shutdown(). 1362** 1363** Among other things, ^sqlite3_initialize() will invoke 1364** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1365** will invoke sqlite3_os_end(). 1366** 1367** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1368** ^If for some reason, sqlite3_initialize() is unable to initialize 1369** the library (perhaps it is unable to allocate a needed resource such 1370** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1371** 1372** ^The sqlite3_initialize() routine is called internally by many other 1373** SQLite interfaces so that an application usually does not need to 1374** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1375** calls sqlite3_initialize() so the SQLite library will be automatically 1376** initialized when [sqlite3_open()] is called if it has not be initialized 1377** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1378** compile-time option, then the automatic calls to sqlite3_initialize() 1379** are omitted and the application must call sqlite3_initialize() directly 1380** prior to using any other SQLite interface. For maximum portability, 1381** it is recommended that applications always invoke sqlite3_initialize() 1382** directly prior to using any other SQLite interface. Future releases 1383** of SQLite may require this. In other words, the behavior exhibited 1384** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1385** default behavior in some future release of SQLite. 1386** 1387** The sqlite3_os_init() routine does operating-system specific 1388** initialization of the SQLite library. The sqlite3_os_end() 1389** routine undoes the effect of sqlite3_os_init(). Typical tasks 1390** performed by these routines include allocation or deallocation 1391** of static resources, initialization of global variables, 1392** setting up a default [sqlite3_vfs] module, or setting up 1393** a default configuration using [sqlite3_config()]. 1394** 1395** The application should never invoke either sqlite3_os_init() 1396** or sqlite3_os_end() directly. The application should only invoke 1397** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1398** interface is called automatically by sqlite3_initialize() and 1399** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1400** implementations for sqlite3_os_init() and sqlite3_os_end() 1401** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1402** When [custom builds | built for other platforms] 1403** (using the [SQLITE_OS_OTHER=1] compile-time 1404** option) the application must supply a suitable implementation for 1405** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1406** implementation of sqlite3_os_init() or sqlite3_os_end() 1407** must return [SQLITE_OK] on success and some other [error code] upon 1408** failure. 1409*/ 1410int sqlite3_initialize(void); 1411int sqlite3_shutdown(void); 1412int sqlite3_os_init(void); 1413int sqlite3_os_end(void); 1414 1415/* 1416** CAPI3REF: Configuring The SQLite Library 1417** 1418** The sqlite3_config() interface is used to make global configuration 1419** changes to SQLite in order to tune SQLite to the specific needs of 1420** the application. The default configuration is recommended for most 1421** applications and so this routine is usually not necessary. It is 1422** provided to support rare applications with unusual needs. 1423** 1424** <b>The sqlite3_config() interface is not threadsafe. The application 1425** must ensure that no other SQLite interfaces are invoked by other 1426** threads while sqlite3_config() is running.</b> 1427** 1428** The sqlite3_config() interface 1429** may only be invoked prior to library initialization using 1430** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1431** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1432** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1433** Note, however, that ^sqlite3_config() can be called as part of the 1434** implementation of an application-defined [sqlite3_os_init()]. 1435** 1436** The first argument to sqlite3_config() is an integer 1437** [configuration option] that determines 1438** what property of SQLite is to be configured. Subsequent arguments 1439** vary depending on the [configuration option] 1440** in the first argument. 1441** 1442** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1443** ^If the option is unknown or SQLite is unable to set the option 1444** then this routine returns a non-zero [error code]. 1445*/ 1446int sqlite3_config(int, ...); 1447 1448/* 1449** CAPI3REF: Configure database connections 1450** METHOD: sqlite3 1451** 1452** The sqlite3_db_config() interface is used to make configuration 1453** changes to a [database connection]. The interface is similar to 1454** [sqlite3_config()] except that the changes apply to a single 1455** [database connection] (specified in the first argument). 1456** 1457** The second argument to sqlite3_db_config(D,V,...) is the 1458** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1459** that indicates what aspect of the [database connection] is being configured. 1460** Subsequent arguments vary depending on the configuration verb. 1461** 1462** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1463** the call is considered successful. 1464*/ 1465int sqlite3_db_config(sqlite3*, int op, ...); 1466 1467/* 1468** CAPI3REF: Memory Allocation Routines 1469** 1470** An instance of this object defines the interface between SQLite 1471** and low-level memory allocation routines. 1472** 1473** This object is used in only one place in the SQLite interface. 1474** A pointer to an instance of this object is the argument to 1475** [sqlite3_config()] when the configuration option is 1476** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1477** By creating an instance of this object 1478** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1479** during configuration, an application can specify an alternative 1480** memory allocation subsystem for SQLite to use for all of its 1481** dynamic memory needs. 1482** 1483** Note that SQLite comes with several [built-in memory allocators] 1484** that are perfectly adequate for the overwhelming majority of applications 1485** and that this object is only useful to a tiny minority of applications 1486** with specialized memory allocation requirements. This object is 1487** also used during testing of SQLite in order to specify an alternative 1488** memory allocator that simulates memory out-of-memory conditions in 1489** order to verify that SQLite recovers gracefully from such 1490** conditions. 1491** 1492** The xMalloc, xRealloc, and xFree methods must work like the 1493** malloc(), realloc() and free() functions from the standard C library. 1494** ^SQLite guarantees that the second argument to 1495** xRealloc is always a value returned by a prior call to xRoundup. 1496** 1497** xSize should return the allocated size of a memory allocation 1498** previously obtained from xMalloc or xRealloc. The allocated size 1499** is always at least as big as the requested size but may be larger. 1500** 1501** The xRoundup method returns what would be the allocated size of 1502** a memory allocation given a particular requested size. Most memory 1503** allocators round up memory allocations at least to the next multiple 1504** of 8. Some allocators round up to a larger multiple or to a power of 2. 1505** Every memory allocation request coming in through [sqlite3_malloc()] 1506** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1507** that causes the corresponding memory allocation to fail. 1508** 1509** The xInit method initializes the memory allocator. For example, 1510** it might allocate any require mutexes or initialize internal data 1511** structures. The xShutdown method is invoked (indirectly) by 1512** [sqlite3_shutdown()] and should deallocate any resources acquired 1513** by xInit. The pAppData pointer is used as the only parameter to 1514** xInit and xShutdown. 1515** 1516** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1517** the xInit method, so the xInit method need not be threadsafe. The 1518** xShutdown method is only called from [sqlite3_shutdown()] so it does 1519** not need to be threadsafe either. For all other methods, SQLite 1520** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1521** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1522** it is by default) and so the methods are automatically serialized. 1523** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1524** methods must be threadsafe or else make their own arrangements for 1525** serialization. 1526** 1527** SQLite will never invoke xInit() more than once without an intervening 1528** call to xShutdown(). 1529*/ 1530typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1531struct sqlite3_mem_methods { 1532 void *(*xMalloc)(int); /* Memory allocation function */ 1533 void (*xFree)(void*); /* Free a prior allocation */ 1534 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1535 int (*xSize)(void*); /* Return the size of an allocation */ 1536 int (*xRoundup)(int); /* Round up request size to allocation size */ 1537 int (*xInit)(void*); /* Initialize the memory allocator */ 1538 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1539 void *pAppData; /* Argument to xInit() and xShutdown() */ 1540}; 1541 1542/* 1543** CAPI3REF: Configuration Options 1544** KEYWORDS: {configuration option} 1545** 1546** These constants are the available integer configuration options that 1547** can be passed as the first argument to the [sqlite3_config()] interface. 1548** 1549** New configuration options may be added in future releases of SQLite. 1550** Existing configuration options might be discontinued. Applications 1551** should check the return code from [sqlite3_config()] to make sure that 1552** the call worked. The [sqlite3_config()] interface will return a 1553** non-zero [error code] if a discontinued or unsupported configuration option 1554** is invoked. 1555** 1556** <dl> 1557** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1558** <dd>There are no arguments to this option. ^This option sets the 1559** [threading mode] to Single-thread. In other words, it disables 1560** all mutexing and puts SQLite into a mode where it can only be used 1561** by a single thread. ^If SQLite is compiled with 1562** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1563** it is not possible to change the [threading mode] from its default 1564** value of Single-thread and so [sqlite3_config()] will return 1565** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1566** configuration option.</dd> 1567** 1568** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1569** <dd>There are no arguments to this option. ^This option sets the 1570** [threading mode] to Multi-thread. In other words, it disables 1571** mutexing on [database connection] and [prepared statement] objects. 1572** The application is responsible for serializing access to 1573** [database connections] and [prepared statements]. But other mutexes 1574** are enabled so that SQLite will be safe to use in a multi-threaded 1575** environment as long as no two threads attempt to use the same 1576** [database connection] at the same time. ^If SQLite is compiled with 1577** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1578** it is not possible to set the Multi-thread [threading mode] and 1579** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1580** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1581** 1582** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1583** <dd>There are no arguments to this option. ^This option sets the 1584** [threading mode] to Serialized. In other words, this option enables 1585** all mutexes including the recursive 1586** mutexes on [database connection] and [prepared statement] objects. 1587** In this mode (which is the default when SQLite is compiled with 1588** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1589** to [database connections] and [prepared statements] so that the 1590** application is free to use the same [database connection] or the 1591** same [prepared statement] in different threads at the same time. 1592** ^If SQLite is compiled with 1593** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1594** it is not possible to set the Serialized [threading mode] and 1595** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1596** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1597** 1598** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1599** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1600** a pointer to an instance of the [sqlite3_mem_methods] structure. 1601** The argument specifies 1602** alternative low-level memory allocation routines to be used in place of 1603** the memory allocation routines built into SQLite.)^ ^SQLite makes 1604** its own private copy of the content of the [sqlite3_mem_methods] structure 1605** before the [sqlite3_config()] call returns.</dd> 1606** 1607** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1608** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1609** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1610** The [sqlite3_mem_methods] 1611** structure is filled with the currently defined memory allocation routines.)^ 1612** This option can be used to overload the default memory allocation 1613** routines with a wrapper that simulations memory allocation failure or 1614** tracks memory usage, for example. </dd> 1615** 1616** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1617** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1618** interpreted as a boolean, which enables or disables the collection of 1619** memory allocation statistics. ^(When memory allocation statistics are 1620** disabled, the following SQLite interfaces become non-operational: 1621** <ul> 1622** <li> [sqlite3_memory_used()] 1623** <li> [sqlite3_memory_highwater()] 1624** <li> [sqlite3_soft_heap_limit64()] 1625** <li> [sqlite3_status64()] 1626** </ul>)^ 1627** ^Memory allocation statistics are enabled by default unless SQLite is 1628** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1629** allocation statistics are disabled by default. 1630** </dd> 1631** 1632** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1633** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer 1634** that SQLite can use for scratch memory. ^(There are three arguments 1635** to SQLITE_CONFIG_SCRATCH: A pointer an 8-byte 1636** aligned memory buffer from which the scratch allocations will be 1637** drawn, the size of each scratch allocation (sz), 1638** and the maximum number of scratch allocations (N).)^ 1639** The first argument must be a pointer to an 8-byte aligned buffer 1640** of at least sz*N bytes of memory. 1641** ^SQLite will not use more than one scratch buffers per thread. 1642** ^SQLite will never request a scratch buffer that is more than 6 1643** times the database page size. 1644** ^If SQLite needs needs additional 1645** scratch memory beyond what is provided by this configuration option, then 1646** [sqlite3_malloc()] will be used to obtain the memory needed.<p> 1647** ^When the application provides any amount of scratch memory using 1648** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large 1649** [sqlite3_malloc|heap allocations]. 1650** This can help [Robson proof|prevent memory allocation failures] due to heap 1651** fragmentation in low-memory embedded systems. 1652** </dd> 1653** 1654** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1655** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1656** that SQLite can use for the database page cache with the default page 1657** cache implementation. 1658** This configuration option is a no-op if an application-define page 1659** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1660** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1661** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1662** and the number of cache lines (N). 1663** The sz argument should be the size of the largest database page 1664** (a power of two between 512 and 65536) plus some extra bytes for each 1665** page header. ^The number of extra bytes needed by the page header 1666** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1667** ^It is harmless, apart from the wasted memory, 1668** for the sz parameter to be larger than necessary. The pMem 1669** argument must be either a NULL pointer or a pointer to an 8-byte 1670** aligned block of memory of at least sz*N bytes, otherwise 1671** subsequent behavior is undefined. 1672** ^When pMem is not NULL, SQLite will strive to use the memory provided 1673** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1674** a page cache line is larger than sz bytes or if all of the pMem buffer 1675** is exhausted. 1676** ^If pMem is NULL and N is non-zero, then each database connection 1677** does an initial bulk allocation for page cache memory 1678** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1679** of -1024*N bytes if N is negative, . ^If additional 1680** page cache memory is needed beyond what is provided by the initial 1681** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1682** additional cache line. </dd> 1683** 1684** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1685** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1686** that SQLite will use for all of its dynamic memory allocation needs 1687** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and 1688** [SQLITE_CONFIG_PAGECACHE]. 1689** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1690** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1691** [SQLITE_ERROR] if invoked otherwise. 1692** ^There are three arguments to SQLITE_CONFIG_HEAP: 1693** An 8-byte aligned pointer to the memory, 1694** the number of bytes in the memory buffer, and the minimum allocation size. 1695** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1696** to using its default memory allocator (the system malloc() implementation), 1697** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1698** memory pointer is not NULL then the alternative memory 1699** allocator is engaged to handle all of SQLites memory allocation needs. 1700** The first pointer (the memory pointer) must be aligned to an 8-byte 1701** boundary or subsequent behavior of SQLite will be undefined. 1702** The minimum allocation size is capped at 2**12. Reasonable values 1703** for the minimum allocation size are 2**5 through 2**8.</dd> 1704** 1705** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1706** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1707** pointer to an instance of the [sqlite3_mutex_methods] structure. 1708** The argument specifies alternative low-level mutex routines to be used 1709** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1710** the content of the [sqlite3_mutex_methods] structure before the call to 1711** [sqlite3_config()] returns. ^If SQLite is compiled with 1712** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1713** the entire mutexing subsystem is omitted from the build and hence calls to 1714** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1715** return [SQLITE_ERROR].</dd> 1716** 1717** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1718** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1719** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1720** [sqlite3_mutex_methods] 1721** structure is filled with the currently defined mutex routines.)^ 1722** This option can be used to overload the default mutex allocation 1723** routines with a wrapper used to track mutex usage for performance 1724** profiling or testing, for example. ^If SQLite is compiled with 1725** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1726** the entire mutexing subsystem is omitted from the build and hence calls to 1727** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1728** return [SQLITE_ERROR].</dd> 1729** 1730** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1731** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1732** the default size of lookaside memory on each [database connection]. 1733** The first argument is the 1734** size of each lookaside buffer slot and the second is the number of 1735** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1736** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1737** option to [sqlite3_db_config()] can be used to change the lookaside 1738** configuration on individual connections.)^ </dd> 1739** 1740** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1741** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1742** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1743** the interface to a custom page cache implementation.)^ 1744** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1745** 1746** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1747** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1748** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1749** the current page cache implementation into that object.)^ </dd> 1750** 1751** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1752** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1753** global [error log]. 1754** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1755** function with a call signature of void(*)(void*,int,const char*), 1756** and a pointer to void. ^If the function pointer is not NULL, it is 1757** invoked by [sqlite3_log()] to process each logging event. ^If the 1758** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1759** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1760** passed through as the first parameter to the application-defined logger 1761** function whenever that function is invoked. ^The second parameter to 1762** the logger function is a copy of the first parameter to the corresponding 1763** [sqlite3_log()] call and is intended to be a [result code] or an 1764** [extended result code]. ^The third parameter passed to the logger is 1765** log message after formatting via [sqlite3_snprintf()]. 1766** The SQLite logging interface is not reentrant; the logger function 1767** supplied by the application must not invoke any SQLite interface. 1768** In a multi-threaded application, the application-defined logger 1769** function must be threadsafe. </dd> 1770** 1771** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1772** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1773** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1774** then URI handling is globally disabled.)^ ^If URI handling is globally 1775** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1776** [sqlite3_open16()] or 1777** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1778** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1779** connection is opened. ^If it is globally disabled, filenames are 1780** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1781** database connection is opened. ^(By default, URI handling is globally 1782** disabled. The default value may be changed by compiling with the 1783** [SQLITE_USE_URI] symbol defined.)^ 1784** 1785** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1786** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1787** argument which is interpreted as a boolean in order to enable or disable 1788** the use of covering indices for full table scans in the query optimizer. 1789** ^The default setting is determined 1790** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1791** if that compile-time option is omitted. 1792** The ability to disable the use of covering indices for full table scans 1793** is because some incorrectly coded legacy applications might malfunction 1794** when the optimization is enabled. Providing the ability to 1795** disable the optimization allows the older, buggy application code to work 1796** without change even with newer versions of SQLite. 1797** 1798** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1799** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1800** <dd> These options are obsolete and should not be used by new code. 1801** They are retained for backwards compatibility but are now no-ops. 1802** </dd> 1803** 1804** [[SQLITE_CONFIG_SQLLOG]] 1805** <dt>SQLITE_CONFIG_SQLLOG 1806** <dd>This option is only available if sqlite is compiled with the 1807** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1808** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1809** The second should be of type (void*). The callback is invoked by the library 1810** in three separate circumstances, identified by the value passed as the 1811** fourth parameter. If the fourth parameter is 0, then the database connection 1812** passed as the second argument has just been opened. The third argument 1813** points to a buffer containing the name of the main database file. If the 1814** fourth parameter is 1, then the SQL statement that the third parameter 1815** points to has just been executed. Or, if the fourth parameter is 2, then 1816** the connection being passed as the second parameter is being closed. The 1817** third parameter is passed NULL In this case. An example of using this 1818** configuration option can be seen in the "test_sqllog.c" source file in 1819** the canonical SQLite source tree.</dd> 1820** 1821** [[SQLITE_CONFIG_MMAP_SIZE]] 1822** <dt>SQLITE_CONFIG_MMAP_SIZE 1823** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1824** that are the default mmap size limit (the default setting for 1825** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1826** ^The default setting can be overridden by each database connection using 1827** either the [PRAGMA mmap_size] command, or by using the 1828** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1829** will be silently truncated if necessary so that it does not exceed the 1830** compile-time maximum mmap size set by the 1831** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1832** ^If either argument to this option is negative, then that argument is 1833** changed to its compile-time default. 1834** 1835** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1836** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1837** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1838** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1839** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1840** that specifies the maximum size of the created heap. 1841** 1842** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1843** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1844** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1845** is a pointer to an integer and writes into that integer the number of extra 1846** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1847** The amount of extra space required can change depending on the compiler, 1848** target platform, and SQLite version. 1849** 1850** [[SQLITE_CONFIG_PMASZ]] 1851** <dt>SQLITE_CONFIG_PMASZ 1852** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1853** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1854** sorter to that integer. The default minimum PMA Size is set by the 1855** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1856** to help with sort operations when multithreaded sorting 1857** is enabled (using the [PRAGMA threads] command) and the amount of content 1858** to be sorted exceeds the page size times the minimum of the 1859** [PRAGMA cache_size] setting and this value. 1860** 1861** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 1862** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 1863** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 1864** becomes the [statement journal] spill-to-disk threshold. 1865** [Statement journals] are held in memory until their size (in bytes) 1866** exceeds this threshold, at which point they are written to disk. 1867** Or if the threshold is -1, statement journals are always held 1868** exclusively in memory. 1869** Since many statement journals never become large, setting the spill 1870** threshold to a value such as 64KiB can greatly reduce the amount of 1871** I/O required to support statement rollback. 1872** The default value for this setting is controlled by the 1873** [SQLITE_STMTJRNL_SPILL] compile-time option. 1874** </dl> 1875*/ 1876#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1877#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1878#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1879#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1880#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1881#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1882#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1883#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1884#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1885#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1886#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1887/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1888#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1889#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1890#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1891#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1892#define SQLITE_CONFIG_URI 17 /* int */ 1893#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1894#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1895#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1896#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1897#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1898#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1899#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1900#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 1901#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 1902 1903/* 1904** CAPI3REF: Database Connection Configuration Options 1905** 1906** These constants are the available integer configuration options that 1907** can be passed as the second argument to the [sqlite3_db_config()] interface. 1908** 1909** New configuration options may be added in future releases of SQLite. 1910** Existing configuration options might be discontinued. Applications 1911** should check the return code from [sqlite3_db_config()] to make sure that 1912** the call worked. ^The [sqlite3_db_config()] interface will return a 1913** non-zero [error code] if a discontinued or unsupported configuration option 1914** is invoked. 1915** 1916** <dl> 1917** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1918** <dd> ^This option takes three additional arguments that determine the 1919** [lookaside memory allocator] configuration for the [database connection]. 1920** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1921** pointer to a memory buffer to use for lookaside memory. 1922** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1923** may be NULL in which case SQLite will allocate the 1924** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1925** size of each lookaside buffer slot. ^The third argument is the number of 1926** slots. The size of the buffer in the first argument must be greater than 1927** or equal to the product of the second and third arguments. The buffer 1928** must be aligned to an 8-byte boundary. ^If the second argument to 1929** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1930** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1931** configuration for a database connection can only be changed when that 1932** connection is not currently using lookaside memory, or in other words 1933** when the "current value" returned by 1934** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1935** Any attempt to change the lookaside memory configuration when lookaside 1936** memory is in use leaves the configuration unchanged and returns 1937** [SQLITE_BUSY].)^</dd> 1938** 1939** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1940** <dd> ^This option is used to enable or disable the enforcement of 1941** [foreign key constraints]. There should be two additional arguments. 1942** The first argument is an integer which is 0 to disable FK enforcement, 1943** positive to enable FK enforcement or negative to leave FK enforcement 1944** unchanged. The second parameter is a pointer to an integer into which 1945** is written 0 or 1 to indicate whether FK enforcement is off or on 1946** following this call. The second parameter may be a NULL pointer, in 1947** which case the FK enforcement setting is not reported back. </dd> 1948** 1949** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1950** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1951** There should be two additional arguments. 1952** The first argument is an integer which is 0 to disable triggers, 1953** positive to enable triggers or negative to leave the setting unchanged. 1954** The second parameter is a pointer to an integer into which 1955** is written 0 or 1 to indicate whether triggers are disabled or enabled 1956** following this call. The second parameter may be a NULL pointer, in 1957** which case the trigger setting is not reported back. </dd> 1958** 1959** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 1960** <dd> ^This option is used to enable or disable the two-argument 1961** version of the [fts3_tokenizer()] function which is part of the 1962** [FTS3] full-text search engine extension. 1963** There should be two additional arguments. 1964** The first argument is an integer which is 0 to disable fts3_tokenizer() or 1965** positive to enable fts3_tokenizer() or negative to leave the setting 1966** unchanged. 1967** The second parameter is a pointer to an integer into which 1968** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 1969** following this call. The second parameter may be a NULL pointer, in 1970** which case the new setting is not reported back. </dd> 1971** 1972** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 1973** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 1974** interface independently of the [load_extension()] SQL function. 1975** The [sqlite3_enable_load_extension()] API enables or disables both the 1976** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 1977** There should be two additional arguments. 1978** When the first argument to this interface is 1, then only the C-API is 1979** enabled and the SQL function remains disabled. If the first argument to 1980** this interface is 0, then both the C-API and the SQL function are disabled. 1981** If the first argument is -1, then no changes are made to state of either the 1982** C-API or the SQL function. 1983** The second parameter is a pointer to an integer into which 1984** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 1985** is disabled or enabled following this call. The second parameter may 1986** be a NULL pointer, in which case the new setting is not reported back. 1987** </dd> 1988** 1989** <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 1990** <dd> ^This option is used to change the name of the "main" database 1991** schema. ^The sole argument is a pointer to a constant UTF8 string 1992** which will become the new schema name in place of "main". ^SQLite 1993** does not make a copy of the new main schema name string, so the application 1994** must ensure that the argument passed into this DBCONFIG option is unchanged 1995** until after the database connection closes. 1996** </dd> 1997** 1998** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 1999** <dd> Usually, when a database in wal mode is closed or detached from a 2000** database handle, SQLite checks if this will mean that there are now no 2001** connections at all to the database. If so, it performs a checkpoint 2002** operation before closing the connection. This option may be used to 2003** override this behaviour. The first parameter passed to this operation 2004** is an integer - non-zero to disable checkpoints-on-close, or zero (the 2005** default) to enable them. The second parameter is a pointer to an integer 2006** into which is written 0 or 1 to indicate whether checkpoints-on-close 2007** have been disabled - 0 if they are not disabled, 1 if they are. 2008** </dd> 2009** 2010** <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2011** <dd>The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2012** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2013** a single SQL query statement will always use the same algorithm regardless 2014** of values of [bound parameters]. The QPSG disables some query optimizations 2015** that look at the values of bound parameters, which can make some queries 2016** slower. But the QPSG has the advantage of more predictable behavior. With 2017** the QPSG active, SQLite will always use the same query plan in the field as 2018** was used during testing in the lab. 2019** </dd> 2020** 2021** </dl> 2022*/ 2023#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2024#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2025#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2026#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2027#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2028#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2029#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2030#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2031 2032 2033/* 2034** CAPI3REF: Enable Or Disable Extended Result Codes 2035** METHOD: sqlite3 2036** 2037** ^The sqlite3_extended_result_codes() routine enables or disables the 2038** [extended result codes] feature of SQLite. ^The extended result 2039** codes are disabled by default for historical compatibility. 2040*/ 2041int sqlite3_extended_result_codes(sqlite3*, int onoff); 2042 2043/* 2044** CAPI3REF: Last Insert Rowid 2045** METHOD: sqlite3 2046** 2047** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2048** has a unique 64-bit signed 2049** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2050** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2051** names are not also used by explicitly declared columns. ^If 2052** the table has a column of type [INTEGER PRIMARY KEY] then that column 2053** is another alias for the rowid. 2054** 2055** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2056** the most recent successful [INSERT] into a rowid table or [virtual table] 2057** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2058** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2059** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2060** zero. 2061** 2062** As well as being set automatically as rows are inserted into database 2063** tables, the value returned by this function may be set explicitly by 2064** [sqlite3_set_last_insert_rowid()] 2065** 2066** Some virtual table implementations may INSERT rows into rowid tables as 2067** part of committing a transaction (e.g. to flush data accumulated in memory 2068** to disk). In this case subsequent calls to this function return the rowid 2069** associated with these internal INSERT operations, which leads to 2070** unintuitive results. Virtual table implementations that do write to rowid 2071** tables in this way can avoid this problem by restoring the original 2072** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2073** control to the user. 2074** 2075** ^(If an [INSERT] occurs within a trigger then this routine will 2076** return the [rowid] of the inserted row as long as the trigger is 2077** running. Once the trigger program ends, the value returned 2078** by this routine reverts to what it was before the trigger was fired.)^ 2079** 2080** ^An [INSERT] that fails due to a constraint violation is not a 2081** successful [INSERT] and does not change the value returned by this 2082** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2083** and INSERT OR ABORT make no changes to the return value of this 2084** routine when their insertion fails. ^(When INSERT OR REPLACE 2085** encounters a constraint violation, it does not fail. The 2086** INSERT continues to completion after deleting rows that caused 2087** the constraint problem so INSERT OR REPLACE will always change 2088** the return value of this interface.)^ 2089** 2090** ^For the purposes of this routine, an [INSERT] is considered to 2091** be successful even if it is subsequently rolled back. 2092** 2093** This function is accessible to SQL statements via the 2094** [last_insert_rowid() SQL function]. 2095** 2096** If a separate thread performs a new [INSERT] on the same 2097** database connection while the [sqlite3_last_insert_rowid()] 2098** function is running and thus changes the last insert [rowid], 2099** then the value returned by [sqlite3_last_insert_rowid()] is 2100** unpredictable and might not equal either the old or the new 2101** last insert [rowid]. 2102*/ 2103sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2104 2105/* 2106** CAPI3REF: Set the Last Insert Rowid value. 2107** METHOD: sqlite3 2108** 2109** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2110** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2111** without inserting a row into the database. 2112*/ 2113void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2114 2115/* 2116** CAPI3REF: Count The Number Of Rows Modified 2117** METHOD: sqlite3 2118** 2119** ^This function returns the number of rows modified, inserted or 2120** deleted by the most recently completed INSERT, UPDATE or DELETE 2121** statement on the database connection specified by the only parameter. 2122** ^Executing any other type of SQL statement does not modify the value 2123** returned by this function. 2124** 2125** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2126** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2127** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2128** 2129** Changes to a view that are intercepted by 2130** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2131** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2132** DELETE statement run on a view is always zero. Only changes made to real 2133** tables are counted. 2134** 2135** Things are more complicated if the sqlite3_changes() function is 2136** executed while a trigger program is running. This may happen if the 2137** program uses the [changes() SQL function], or if some other callback 2138** function invokes sqlite3_changes() directly. Essentially: 2139** 2140** <ul> 2141** <li> ^(Before entering a trigger program the value returned by 2142** sqlite3_changes() function is saved. After the trigger program 2143** has finished, the original value is restored.)^ 2144** 2145** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2146** statement sets the value returned by sqlite3_changes() 2147** upon completion as normal. Of course, this value will not include 2148** any changes performed by sub-triggers, as the sqlite3_changes() 2149** value will be saved and restored after each sub-trigger has run.)^ 2150** </ul> 2151** 2152** ^This means that if the changes() SQL function (or similar) is used 2153** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2154** returns the value as set when the calling statement began executing. 2155** ^If it is used by the second or subsequent such statement within a trigger 2156** program, the value returned reflects the number of rows modified by the 2157** previous INSERT, UPDATE or DELETE statement within the same trigger. 2158** 2159** See also the [sqlite3_total_changes()] interface, the 2160** [count_changes pragma], and the [changes() SQL function]. 2161** 2162** If a separate thread makes changes on the same database connection 2163** while [sqlite3_changes()] is running then the value returned 2164** is unpredictable and not meaningful. 2165*/ 2166int sqlite3_changes(sqlite3*); 2167 2168/* 2169** CAPI3REF: Total Number Of Rows Modified 2170** METHOD: sqlite3 2171** 2172** ^This function returns the total number of rows inserted, modified or 2173** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2174** since the database connection was opened, including those executed as 2175** part of trigger programs. ^Executing any other type of SQL statement 2176** does not affect the value returned by sqlite3_total_changes(). 2177** 2178** ^Changes made as part of [foreign key actions] are included in the 2179** count, but those made as part of REPLACE constraint resolution are 2180** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2181** are not counted. 2182** 2183** See also the [sqlite3_changes()] interface, the 2184** [count_changes pragma], and the [total_changes() SQL function]. 2185** 2186** If a separate thread makes changes on the same database connection 2187** while [sqlite3_total_changes()] is running then the value 2188** returned is unpredictable and not meaningful. 2189*/ 2190int sqlite3_total_changes(sqlite3*); 2191 2192/* 2193** CAPI3REF: Interrupt A Long-Running Query 2194** METHOD: sqlite3 2195** 2196** ^This function causes any pending database operation to abort and 2197** return at its earliest opportunity. This routine is typically 2198** called in response to a user action such as pressing "Cancel" 2199** or Ctrl-C where the user wants a long query operation to halt 2200** immediately. 2201** 2202** ^It is safe to call this routine from a thread different from the 2203** thread that is currently running the database operation. But it 2204** is not safe to call this routine with a [database connection] that 2205** is closed or might close before sqlite3_interrupt() returns. 2206** 2207** ^If an SQL operation is very nearly finished at the time when 2208** sqlite3_interrupt() is called, then it might not have an opportunity 2209** to be interrupted and might continue to completion. 2210** 2211** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2212** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2213** that is inside an explicit transaction, then the entire transaction 2214** will be rolled back automatically. 2215** 2216** ^The sqlite3_interrupt(D) call is in effect until all currently running 2217** SQL statements on [database connection] D complete. ^Any new SQL statements 2218** that are started after the sqlite3_interrupt() call and before the 2219** running statements reaches zero are interrupted as if they had been 2220** running prior to the sqlite3_interrupt() call. ^New SQL statements 2221** that are started after the running statement count reaches zero are 2222** not effected by the sqlite3_interrupt(). 2223** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2224** SQL statements is a no-op and has no effect on SQL statements 2225** that are started after the sqlite3_interrupt() call returns. 2226*/ 2227void sqlite3_interrupt(sqlite3*); 2228 2229/* 2230** CAPI3REF: Determine If An SQL Statement Is Complete 2231** 2232** These routines are useful during command-line input to determine if the 2233** currently entered text seems to form a complete SQL statement or 2234** if additional input is needed before sending the text into 2235** SQLite for parsing. ^These routines return 1 if the input string 2236** appears to be a complete SQL statement. ^A statement is judged to be 2237** complete if it ends with a semicolon token and is not a prefix of a 2238** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2239** string literals or quoted identifier names or comments are not 2240** independent tokens (they are part of the token in which they are 2241** embedded) and thus do not count as a statement terminator. ^Whitespace 2242** and comments that follow the final semicolon are ignored. 2243** 2244** ^These routines return 0 if the statement is incomplete. ^If a 2245** memory allocation fails, then SQLITE_NOMEM is returned. 2246** 2247** ^These routines do not parse the SQL statements thus 2248** will not detect syntactically incorrect SQL. 2249** 2250** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2251** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2252** automatically by sqlite3_complete16(). If that initialization fails, 2253** then the return value from sqlite3_complete16() will be non-zero 2254** regardless of whether or not the input SQL is complete.)^ 2255** 2256** The input to [sqlite3_complete()] must be a zero-terminated 2257** UTF-8 string. 2258** 2259** The input to [sqlite3_complete16()] must be a zero-terminated 2260** UTF-16 string in native byte order. 2261*/ 2262int sqlite3_complete(const char *sql); 2263int sqlite3_complete16(const void *sql); 2264 2265/* 2266** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2267** KEYWORDS: {busy-handler callback} {busy handler} 2268** METHOD: sqlite3 2269** 2270** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2271** that might be invoked with argument P whenever 2272** an attempt is made to access a database table associated with 2273** [database connection] D when another thread 2274** or process has the table locked. 2275** The sqlite3_busy_handler() interface is used to implement 2276** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2277** 2278** ^If the busy callback is NULL, then [SQLITE_BUSY] 2279** is returned immediately upon encountering the lock. ^If the busy callback 2280** is not NULL, then the callback might be invoked with two arguments. 2281** 2282** ^The first argument to the busy handler is a copy of the void* pointer which 2283** is the third argument to sqlite3_busy_handler(). ^The second argument to 2284** the busy handler callback is the number of times that the busy handler has 2285** been invoked previously for the same locking event. ^If the 2286** busy callback returns 0, then no additional attempts are made to 2287** access the database and [SQLITE_BUSY] is returned 2288** to the application. 2289** ^If the callback returns non-zero, then another attempt 2290** is made to access the database and the cycle repeats. 2291** 2292** The presence of a busy handler does not guarantee that it will be invoked 2293** when there is lock contention. ^If SQLite determines that invoking the busy 2294** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2295** to the application instead of invoking the 2296** busy handler. 2297** Consider a scenario where one process is holding a read lock that 2298** it is trying to promote to a reserved lock and 2299** a second process is holding a reserved lock that it is trying 2300** to promote to an exclusive lock. The first process cannot proceed 2301** because it is blocked by the second and the second process cannot 2302** proceed because it is blocked by the first. If both processes 2303** invoke the busy handlers, neither will make any progress. Therefore, 2304** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2305** will induce the first process to release its read lock and allow 2306** the second process to proceed. 2307** 2308** ^The default busy callback is NULL. 2309** 2310** ^(There can only be a single busy handler defined for each 2311** [database connection]. Setting a new busy handler clears any 2312** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2313** or evaluating [PRAGMA busy_timeout=N] will change the 2314** busy handler and thus clear any previously set busy handler. 2315** 2316** The busy callback should not take any actions which modify the 2317** database connection that invoked the busy handler. In other words, 2318** the busy handler is not reentrant. Any such actions 2319** result in undefined behavior. 2320** 2321** A busy handler must not close the database connection 2322** or [prepared statement] that invoked the busy handler. 2323*/ 2324int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2325 2326/* 2327** CAPI3REF: Set A Busy Timeout 2328** METHOD: sqlite3 2329** 2330** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2331** for a specified amount of time when a table is locked. ^The handler 2332** will sleep multiple times until at least "ms" milliseconds of sleeping 2333** have accumulated. ^After at least "ms" milliseconds of sleeping, 2334** the handler returns 0 which causes [sqlite3_step()] to return 2335** [SQLITE_BUSY]. 2336** 2337** ^Calling this routine with an argument less than or equal to zero 2338** turns off all busy handlers. 2339** 2340** ^(There can only be a single busy handler for a particular 2341** [database connection] at any given moment. If another busy handler 2342** was defined (using [sqlite3_busy_handler()]) prior to calling 2343** this routine, that other busy handler is cleared.)^ 2344** 2345** See also: [PRAGMA busy_timeout] 2346*/ 2347int sqlite3_busy_timeout(sqlite3*, int ms); 2348 2349/* 2350** CAPI3REF: Convenience Routines For Running Queries 2351** METHOD: sqlite3 2352** 2353** This is a legacy interface that is preserved for backwards compatibility. 2354** Use of this interface is not recommended. 2355** 2356** Definition: A <b>result table</b> is memory data structure created by the 2357** [sqlite3_get_table()] interface. A result table records the 2358** complete query results from one or more queries. 2359** 2360** The table conceptually has a number of rows and columns. But 2361** these numbers are not part of the result table itself. These 2362** numbers are obtained separately. Let N be the number of rows 2363** and M be the number of columns. 2364** 2365** A result table is an array of pointers to zero-terminated UTF-8 strings. 2366** There are (N+1)*M elements in the array. The first M pointers point 2367** to zero-terminated strings that contain the names of the columns. 2368** The remaining entries all point to query results. NULL values result 2369** in NULL pointers. All other values are in their UTF-8 zero-terminated 2370** string representation as returned by [sqlite3_column_text()]. 2371** 2372** A result table might consist of one or more memory allocations. 2373** It is not safe to pass a result table directly to [sqlite3_free()]. 2374** A result table should be deallocated using [sqlite3_free_table()]. 2375** 2376** ^(As an example of the result table format, suppose a query result 2377** is as follows: 2378** 2379** <blockquote><pre> 2380** Name | Age 2381** ----------------------- 2382** Alice | 43 2383** Bob | 28 2384** Cindy | 21 2385** </pre></blockquote> 2386** 2387** There are two column (M==2) and three rows (N==3). Thus the 2388** result table has 8 entries. Suppose the result table is stored 2389** in an array names azResult. Then azResult holds this content: 2390** 2391** <blockquote><pre> 2392** azResult[0] = "Name"; 2393** azResult[1] = "Age"; 2394** azResult[2] = "Alice"; 2395** azResult[3] = "43"; 2396** azResult[4] = "Bob"; 2397** azResult[5] = "28"; 2398** azResult[6] = "Cindy"; 2399** azResult[7] = "21"; 2400** </pre></blockquote>)^ 2401** 2402** ^The sqlite3_get_table() function evaluates one or more 2403** semicolon-separated SQL statements in the zero-terminated UTF-8 2404** string of its 2nd parameter and returns a result table to the 2405** pointer given in its 3rd parameter. 2406** 2407** After the application has finished with the result from sqlite3_get_table(), 2408** it must pass the result table pointer to sqlite3_free_table() in order to 2409** release the memory that was malloced. Because of the way the 2410** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2411** function must not try to call [sqlite3_free()] directly. Only 2412** [sqlite3_free_table()] is able to release the memory properly and safely. 2413** 2414** The sqlite3_get_table() interface is implemented as a wrapper around 2415** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2416** to any internal data structures of SQLite. It uses only the public 2417** interface defined here. As a consequence, errors that occur in the 2418** wrapper layer outside of the internal [sqlite3_exec()] call are not 2419** reflected in subsequent calls to [sqlite3_errcode()] or 2420** [sqlite3_errmsg()]. 2421*/ 2422int sqlite3_get_table( 2423 sqlite3 *db, /* An open database */ 2424 const char *zSql, /* SQL to be evaluated */ 2425 char ***pazResult, /* Results of the query */ 2426 int *pnRow, /* Number of result rows written here */ 2427 int *pnColumn, /* Number of result columns written here */ 2428 char **pzErrmsg /* Error msg written here */ 2429); 2430void sqlite3_free_table(char **result); 2431 2432/* 2433** CAPI3REF: Formatted String Printing Functions 2434** 2435** These routines are work-alikes of the "printf()" family of functions 2436** from the standard C library. 2437** These routines understand most of the common K&R formatting options, 2438** plus some additional non-standard formats, detailed below. 2439** Note that some of the more obscure formatting options from recent 2440** C-library standards are omitted from this implementation. 2441** 2442** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2443** results into memory obtained from [sqlite3_malloc()]. 2444** The strings returned by these two routines should be 2445** released by [sqlite3_free()]. ^Both routines return a 2446** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2447** memory to hold the resulting string. 2448** 2449** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2450** the standard C library. The result is written into the 2451** buffer supplied as the second parameter whose size is given by 2452** the first parameter. Note that the order of the 2453** first two parameters is reversed from snprintf().)^ This is an 2454** historical accident that cannot be fixed without breaking 2455** backwards compatibility. ^(Note also that sqlite3_snprintf() 2456** returns a pointer to its buffer instead of the number of 2457** characters actually written into the buffer.)^ We admit that 2458** the number of characters written would be a more useful return 2459** value but we cannot change the implementation of sqlite3_snprintf() 2460** now without breaking compatibility. 2461** 2462** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2463** guarantees that the buffer is always zero-terminated. ^The first 2464** parameter "n" is the total size of the buffer, including space for 2465** the zero terminator. So the longest string that can be completely 2466** written will be n-1 characters. 2467** 2468** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2469** 2470** These routines all implement some additional formatting 2471** options that are useful for constructing SQL statements. 2472** All of the usual printf() formatting options apply. In addition, there 2473** is are "%q", "%Q", "%w" and "%z" options. 2474** 2475** ^(The %q option works like %s in that it substitutes a nul-terminated 2476** string from the argument list. But %q also doubles every '\'' character. 2477** %q is designed for use inside a string literal.)^ By doubling each '\'' 2478** character it escapes that character and allows it to be inserted into 2479** the string. 2480** 2481** For example, assume the string variable zText contains text as follows: 2482** 2483** <blockquote><pre> 2484** char *zText = "It's a happy day!"; 2485** </pre></blockquote> 2486** 2487** One can use this text in an SQL statement as follows: 2488** 2489** <blockquote><pre> 2490** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2491** sqlite3_exec(db, zSQL, 0, 0, 0); 2492** sqlite3_free(zSQL); 2493** </pre></blockquote> 2494** 2495** Because the %q format string is used, the '\'' character in zText 2496** is escaped and the SQL generated is as follows: 2497** 2498** <blockquote><pre> 2499** INSERT INTO table1 VALUES('It''s a happy day!') 2500** </pre></blockquote> 2501** 2502** This is correct. Had we used %s instead of %q, the generated SQL 2503** would have looked like this: 2504** 2505** <blockquote><pre> 2506** INSERT INTO table1 VALUES('It's a happy day!'); 2507** </pre></blockquote> 2508** 2509** This second example is an SQL syntax error. As a general rule you should 2510** always use %q instead of %s when inserting text into a string literal. 2511** 2512** ^(The %Q option works like %q except it also adds single quotes around 2513** the outside of the total string. Additionally, if the parameter in the 2514** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2515** single quotes).)^ So, for example, one could say: 2516** 2517** <blockquote><pre> 2518** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2519** sqlite3_exec(db, zSQL, 0, 0, 0); 2520** sqlite3_free(zSQL); 2521** </pre></blockquote> 2522** 2523** The code above will render a correct SQL statement in the zSQL 2524** variable even if the zText variable is a NULL pointer. 2525** 2526** ^(The "%w" formatting option is like "%q" except that it expects to 2527** be contained within double-quotes instead of single quotes, and it 2528** escapes the double-quote character instead of the single-quote 2529** character.)^ The "%w" formatting option is intended for safely inserting 2530** table and column names into a constructed SQL statement. 2531** 2532** ^(The "%z" formatting option works like "%s" but with the 2533** addition that after the string has been read and copied into 2534** the result, [sqlite3_free()] is called on the input string.)^ 2535*/ 2536char *sqlite3_mprintf(const char*,...); 2537char *sqlite3_vmprintf(const char*, va_list); 2538char *sqlite3_snprintf(int,char*,const char*, ...); 2539char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2540 2541/* 2542** CAPI3REF: Memory Allocation Subsystem 2543** 2544** The SQLite core uses these three routines for all of its own 2545** internal memory allocation needs. "Core" in the previous sentence 2546** does not include operating-system specific VFS implementation. The 2547** Windows VFS uses native malloc() and free() for some operations. 2548** 2549** ^The sqlite3_malloc() routine returns a pointer to a block 2550** of memory at least N bytes in length, where N is the parameter. 2551** ^If sqlite3_malloc() is unable to obtain sufficient free 2552** memory, it returns a NULL pointer. ^If the parameter N to 2553** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2554** a NULL pointer. 2555** 2556** ^The sqlite3_malloc64(N) routine works just like 2557** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2558** of a signed 32-bit integer. 2559** 2560** ^Calling sqlite3_free() with a pointer previously returned 2561** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2562** that it might be reused. ^The sqlite3_free() routine is 2563** a no-op if is called with a NULL pointer. Passing a NULL pointer 2564** to sqlite3_free() is harmless. After being freed, memory 2565** should neither be read nor written. Even reading previously freed 2566** memory might result in a segmentation fault or other severe error. 2567** Memory corruption, a segmentation fault, or other severe error 2568** might result if sqlite3_free() is called with a non-NULL pointer that 2569** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2570** 2571** ^The sqlite3_realloc(X,N) interface attempts to resize a 2572** prior memory allocation X to be at least N bytes. 2573** ^If the X parameter to sqlite3_realloc(X,N) 2574** is a NULL pointer then its behavior is identical to calling 2575** sqlite3_malloc(N). 2576** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2577** negative then the behavior is exactly the same as calling 2578** sqlite3_free(X). 2579** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2580** of at least N bytes in size or NULL if insufficient memory is available. 2581** ^If M is the size of the prior allocation, then min(N,M) bytes 2582** of the prior allocation are copied into the beginning of buffer returned 2583** by sqlite3_realloc(X,N) and the prior allocation is freed. 2584** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2585** prior allocation is not freed. 2586** 2587** ^The sqlite3_realloc64(X,N) interfaces works the same as 2588** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2589** of a 32-bit signed integer. 2590** 2591** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2592** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2593** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2594** ^The value returned by sqlite3_msize(X) might be larger than the number 2595** of bytes requested when X was allocated. ^If X is a NULL pointer then 2596** sqlite3_msize(X) returns zero. If X points to something that is not 2597** the beginning of memory allocation, or if it points to a formerly 2598** valid memory allocation that has now been freed, then the behavior 2599** of sqlite3_msize(X) is undefined and possibly harmful. 2600** 2601** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2602** sqlite3_malloc64(), and sqlite3_realloc64() 2603** is always aligned to at least an 8 byte boundary, or to a 2604** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2605** option is used. 2606** 2607** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2608** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2609** implementation of these routines to be omitted. That capability 2610** is no longer provided. Only built-in memory allocators can be used. 2611** 2612** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2613** the system malloc() and free() directly when converting 2614** filenames between the UTF-8 encoding used by SQLite 2615** and whatever filename encoding is used by the particular Windows 2616** installation. Memory allocation errors were detected, but 2617** they were reported back as [SQLITE_CANTOPEN] or 2618** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2619** 2620** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2621** must be either NULL or else pointers obtained from a prior 2622** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2623** not yet been released. 2624** 2625** The application must not read or write any part of 2626** a block of memory after it has been released using 2627** [sqlite3_free()] or [sqlite3_realloc()]. 2628*/ 2629void *sqlite3_malloc(int); 2630void *sqlite3_malloc64(sqlite3_uint64); 2631void *sqlite3_realloc(void*, int); 2632void *sqlite3_realloc64(void*, sqlite3_uint64); 2633void sqlite3_free(void*); 2634sqlite3_uint64 sqlite3_msize(void*); 2635 2636/* 2637** CAPI3REF: Memory Allocator Statistics 2638** 2639** SQLite provides these two interfaces for reporting on the status 2640** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2641** routines, which form the built-in memory allocation subsystem. 2642** 2643** ^The [sqlite3_memory_used()] routine returns the number of bytes 2644** of memory currently outstanding (malloced but not freed). 2645** ^The [sqlite3_memory_highwater()] routine returns the maximum 2646** value of [sqlite3_memory_used()] since the high-water mark 2647** was last reset. ^The values returned by [sqlite3_memory_used()] and 2648** [sqlite3_memory_highwater()] include any overhead 2649** added by SQLite in its implementation of [sqlite3_malloc()], 2650** but not overhead added by the any underlying system library 2651** routines that [sqlite3_malloc()] may call. 2652** 2653** ^The memory high-water mark is reset to the current value of 2654** [sqlite3_memory_used()] if and only if the parameter to 2655** [sqlite3_memory_highwater()] is true. ^The value returned 2656** by [sqlite3_memory_highwater(1)] is the high-water mark 2657** prior to the reset. 2658*/ 2659sqlite3_int64 sqlite3_memory_used(void); 2660sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2661 2662/* 2663** CAPI3REF: Pseudo-Random Number Generator 2664** 2665** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2666** select random [ROWID | ROWIDs] when inserting new records into a table that 2667** already uses the largest possible [ROWID]. The PRNG is also used for 2668** the build-in random() and randomblob() SQL functions. This interface allows 2669** applications to access the same PRNG for other purposes. 2670** 2671** ^A call to this routine stores N bytes of randomness into buffer P. 2672** ^The P parameter can be a NULL pointer. 2673** 2674** ^If this routine has not been previously called or if the previous 2675** call had N less than one or a NULL pointer for P, then the PRNG is 2676** seeded using randomness obtained from the xRandomness method of 2677** the default [sqlite3_vfs] object. 2678** ^If the previous call to this routine had an N of 1 or more and a 2679** non-NULL P then the pseudo-randomness is generated 2680** internally and without recourse to the [sqlite3_vfs] xRandomness 2681** method. 2682*/ 2683void sqlite3_randomness(int N, void *P); 2684 2685/* 2686** CAPI3REF: Compile-Time Authorization Callbacks 2687** METHOD: sqlite3 2688** KEYWORDS: {authorizer callback} 2689** 2690** ^This routine registers an authorizer callback with a particular 2691** [database connection], supplied in the first argument. 2692** ^The authorizer callback is invoked as SQL statements are being compiled 2693** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2694** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2695** points during the compilation process, as logic is being created 2696** to perform various actions, the authorizer callback is invoked to 2697** see if those actions are allowed. ^The authorizer callback should 2698** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2699** specific action but allow the SQL statement to continue to be 2700** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2701** rejected with an error. ^If the authorizer callback returns 2702** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2703** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2704** the authorizer will fail with an error message. 2705** 2706** When the callback returns [SQLITE_OK], that means the operation 2707** requested is ok. ^When the callback returns [SQLITE_DENY], the 2708** [sqlite3_prepare_v2()] or equivalent call that triggered the 2709** authorizer will fail with an error message explaining that 2710** access is denied. 2711** 2712** ^The first parameter to the authorizer callback is a copy of the third 2713** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2714** to the callback is an integer [SQLITE_COPY | action code] that specifies 2715** the particular action to be authorized. ^The third through sixth parameters 2716** to the callback are either NULL pointers or zero-terminated strings 2717** that contain additional details about the action to be authorized. 2718** Applications must always be prepared to encounter a NULL pointer in any 2719** of the third through the sixth parameters of the authorization callback. 2720** 2721** ^If the action code is [SQLITE_READ] 2722** and the callback returns [SQLITE_IGNORE] then the 2723** [prepared statement] statement is constructed to substitute 2724** a NULL value in place of the table column that would have 2725** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2726** return can be used to deny an untrusted user access to individual 2727** columns of a table. 2728** ^When a table is referenced by a [SELECT] but no column values are 2729** extracted from that table (for example in a query like 2730** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2731** is invoked once for that table with a column name that is an empty string. 2732** ^If the action code is [SQLITE_DELETE] and the callback returns 2733** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2734** [truncate optimization] is disabled and all rows are deleted individually. 2735** 2736** An authorizer is used when [sqlite3_prepare | preparing] 2737** SQL statements from an untrusted source, to ensure that the SQL statements 2738** do not try to access data they are not allowed to see, or that they do not 2739** try to execute malicious statements that damage the database. For 2740** example, an application may allow a user to enter arbitrary 2741** SQL queries for evaluation by a database. But the application does 2742** not want the user to be able to make arbitrary changes to the 2743** database. An authorizer could then be put in place while the 2744** user-entered SQL is being [sqlite3_prepare | prepared] that 2745** disallows everything except [SELECT] statements. 2746** 2747** Applications that need to process SQL from untrusted sources 2748** might also consider lowering resource limits using [sqlite3_limit()] 2749** and limiting database size using the [max_page_count] [PRAGMA] 2750** in addition to using an authorizer. 2751** 2752** ^(Only a single authorizer can be in place on a database connection 2753** at a time. Each call to sqlite3_set_authorizer overrides the 2754** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2755** The authorizer is disabled by default. 2756** 2757** The authorizer callback must not do anything that will modify 2758** the database connection that invoked the authorizer callback. 2759** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2760** database connections for the meaning of "modify" in this paragraph. 2761** 2762** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2763** statement might be re-prepared during [sqlite3_step()] due to a 2764** schema change. Hence, the application should ensure that the 2765** correct authorizer callback remains in place during the [sqlite3_step()]. 2766** 2767** ^Note that the authorizer callback is invoked only during 2768** [sqlite3_prepare()] or its variants. Authorization is not 2769** performed during statement evaluation in [sqlite3_step()], unless 2770** as stated in the previous paragraph, sqlite3_step() invokes 2771** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2772*/ 2773int sqlite3_set_authorizer( 2774 sqlite3*, 2775 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2776 void *pUserData 2777); 2778 2779/* 2780** CAPI3REF: Authorizer Return Codes 2781** 2782** The [sqlite3_set_authorizer | authorizer callback function] must 2783** return either [SQLITE_OK] or one of these two constants in order 2784** to signal SQLite whether or not the action is permitted. See the 2785** [sqlite3_set_authorizer | authorizer documentation] for additional 2786** information. 2787** 2788** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2789** returned from the [sqlite3_vtab_on_conflict()] interface. 2790*/ 2791#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2792#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2793 2794/* 2795** CAPI3REF: Authorizer Action Codes 2796** 2797** The [sqlite3_set_authorizer()] interface registers a callback function 2798** that is invoked to authorize certain SQL statement actions. The 2799** second parameter to the callback is an integer code that specifies 2800** what action is being authorized. These are the integer action codes that 2801** the authorizer callback may be passed. 2802** 2803** These action code values signify what kind of operation is to be 2804** authorized. The 3rd and 4th parameters to the authorization 2805** callback function will be parameters or NULL depending on which of these 2806** codes is used as the second parameter. ^(The 5th parameter to the 2807** authorizer callback is the name of the database ("main", "temp", 2808** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2809** is the name of the inner-most trigger or view that is responsible for 2810** the access attempt or NULL if this access attempt is directly from 2811** top-level SQL code. 2812*/ 2813/******************************************* 3rd ************ 4th ***********/ 2814#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2815#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2816#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2817#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2818#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2819#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2820#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2821#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2822#define SQLITE_DELETE 9 /* Table Name NULL */ 2823#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2824#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2825#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2826#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2827#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2828#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2829#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2830#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2831#define SQLITE_INSERT 18 /* Table Name NULL */ 2832#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2833#define SQLITE_READ 20 /* Table Name Column Name */ 2834#define SQLITE_SELECT 21 /* NULL NULL */ 2835#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2836#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2837#define SQLITE_ATTACH 24 /* Filename NULL */ 2838#define SQLITE_DETACH 25 /* Database Name NULL */ 2839#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2840#define SQLITE_REINDEX 27 /* Index Name NULL */ 2841#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2842#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2843#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2844#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2845#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2846#define SQLITE_COPY 0 /* No longer used */ 2847#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2848 2849/* 2850** CAPI3REF: Tracing And Profiling Functions 2851** METHOD: sqlite3 2852** 2853** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 2854** instead of the routines described here. 2855** 2856** These routines register callback functions that can be used for 2857** tracing and profiling the execution of SQL statements. 2858** 2859** ^The callback function registered by sqlite3_trace() is invoked at 2860** various times when an SQL statement is being run by [sqlite3_step()]. 2861** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2862** SQL statement text as the statement first begins executing. 2863** ^(Additional sqlite3_trace() callbacks might occur 2864** as each triggered subprogram is entered. The callbacks for triggers 2865** contain a UTF-8 SQL comment that identifies the trigger.)^ 2866** 2867** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2868** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2869** 2870** ^The callback function registered by sqlite3_profile() is invoked 2871** as each SQL statement finishes. ^The profile callback contains 2872** the original statement text and an estimate of wall-clock time 2873** of how long that statement took to run. ^The profile callback 2874** time is in units of nanoseconds, however the current implementation 2875** is only capable of millisecond resolution so the six least significant 2876** digits in the time are meaningless. Future versions of SQLite 2877** might provide greater resolution on the profiler callback. The 2878** sqlite3_profile() function is considered experimental and is 2879** subject to change in future versions of SQLite. 2880*/ 2881SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 2882 void(*xTrace)(void*,const char*), void*); 2883SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 2884 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2885 2886/* 2887** CAPI3REF: SQL Trace Event Codes 2888** KEYWORDS: SQLITE_TRACE 2889** 2890** These constants identify classes of events that can be monitored 2891** using the [sqlite3_trace_v2()] tracing logic. The third argument 2892** to [sqlite3_trace_v2()] is an OR-ed combination of one or more of 2893** the following constants. ^The first argument to the trace callback 2894** is one of the following constants. 2895** 2896** New tracing constants may be added in future releases. 2897** 2898** ^A trace callback has four arguments: xCallback(T,C,P,X). 2899** ^The T argument is one of the integer type codes above. 2900** ^The C argument is a copy of the context pointer passed in as the 2901** fourth argument to [sqlite3_trace_v2()]. 2902** The P and X arguments are pointers whose meanings depend on T. 2903** 2904** <dl> 2905** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 2906** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 2907** first begins running and possibly at other times during the 2908** execution of the prepared statement, such as at the start of each 2909** trigger subprogram. ^The P argument is a pointer to the 2910** [prepared statement]. ^The X argument is a pointer to a string which 2911** is the unexpanded SQL text of the prepared statement or an SQL comment 2912** that indicates the invocation of a trigger. ^The callback can compute 2913** the same text that would have been returned by the legacy [sqlite3_trace()] 2914** interface by using the X argument when X begins with "--" and invoking 2915** [sqlite3_expanded_sql(P)] otherwise. 2916** 2917** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 2918** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 2919** information as is provided by the [sqlite3_profile()] callback. 2920** ^The P argument is a pointer to the [prepared statement] and the 2921** X argument points to a 64-bit integer which is the estimated of 2922** the number of nanosecond that the prepared statement took to run. 2923** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 2924** 2925** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 2926** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 2927** statement generates a single row of result. 2928** ^The P argument is a pointer to the [prepared statement] and the 2929** X argument is unused. 2930** 2931** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 2932** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 2933** connection closes. 2934** ^The P argument is a pointer to the [database connection] object 2935** and the X argument is unused. 2936** </dl> 2937*/ 2938#define SQLITE_TRACE_STMT 0x01 2939#define SQLITE_TRACE_PROFILE 0x02 2940#define SQLITE_TRACE_ROW 0x04 2941#define SQLITE_TRACE_CLOSE 0x08 2942 2943/* 2944** CAPI3REF: SQL Trace Hook 2945** METHOD: sqlite3 2946** 2947** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 2948** function X against [database connection] D, using property mask M 2949** and context pointer P. ^If the X callback is 2950** NULL or if the M mask is zero, then tracing is disabled. The 2951** M argument should be the bitwise OR-ed combination of 2952** zero or more [SQLITE_TRACE] constants. 2953** 2954** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 2955** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 2956** 2957** ^The X callback is invoked whenever any of the events identified by 2958** mask M occur. ^The integer return value from the callback is currently 2959** ignored, though this may change in future releases. Callback 2960** implementations should return zero to ensure future compatibility. 2961** 2962** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 2963** ^The T argument is one of the [SQLITE_TRACE] 2964** constants to indicate why the callback was invoked. 2965** ^The C argument is a copy of the context pointer. 2966** The P and X arguments are pointers whose meanings depend on T. 2967** 2968** The sqlite3_trace_v2() interface is intended to replace the legacy 2969** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 2970** are deprecated. 2971*/ 2972int sqlite3_trace_v2( 2973 sqlite3*, 2974 unsigned uMask, 2975 int(*xCallback)(unsigned,void*,void*,void*), 2976 void *pCtx 2977); 2978 2979/* 2980** CAPI3REF: Query Progress Callbacks 2981** METHOD: sqlite3 2982** 2983** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2984** function X to be invoked periodically during long running calls to 2985** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2986** database connection D. An example use for this 2987** interface is to keep a GUI updated during a large query. 2988** 2989** ^The parameter P is passed through as the only parameter to the 2990** callback function X. ^The parameter N is the approximate number of 2991** [virtual machine instructions] that are evaluated between successive 2992** invocations of the callback X. ^If N is less than one then the progress 2993** handler is disabled. 2994** 2995** ^Only a single progress handler may be defined at one time per 2996** [database connection]; setting a new progress handler cancels the 2997** old one. ^Setting parameter X to NULL disables the progress handler. 2998** ^The progress handler is also disabled by setting N to a value less 2999** than 1. 3000** 3001** ^If the progress callback returns non-zero, the operation is 3002** interrupted. This feature can be used to implement a 3003** "Cancel" button on a GUI progress dialog box. 3004** 3005** The progress handler callback must not do anything that will modify 3006** the database connection that invoked the progress handler. 3007** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3008** database connections for the meaning of "modify" in this paragraph. 3009** 3010*/ 3011void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3012 3013/* 3014** CAPI3REF: Opening A New Database Connection 3015** CONSTRUCTOR: sqlite3 3016** 3017** ^These routines open an SQLite database file as specified by the 3018** filename argument. ^The filename argument is interpreted as UTF-8 for 3019** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3020** order for sqlite3_open16(). ^(A [database connection] handle is usually 3021** returned in *ppDb, even if an error occurs. The only exception is that 3022** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3023** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3024** object.)^ ^(If the database is opened (and/or created) successfully, then 3025** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3026** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3027** an English language description of the error following a failure of any 3028** of the sqlite3_open() routines. 3029** 3030** ^The default encoding will be UTF-8 for databases created using 3031** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3032** created using sqlite3_open16() will be UTF-16 in the native byte order. 3033** 3034** Whether or not an error occurs when it is opened, resources 3035** associated with the [database connection] handle should be released by 3036** passing it to [sqlite3_close()] when it is no longer required. 3037** 3038** The sqlite3_open_v2() interface works like sqlite3_open() 3039** except that it accepts two additional parameters for additional control 3040** over the new database connection. ^(The flags parameter to 3041** sqlite3_open_v2() can take one of 3042** the following three values, optionally combined with the 3043** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 3044** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 3045** 3046** <dl> 3047** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3048** <dd>The database is opened in read-only mode. If the database does not 3049** already exist, an error is returned.</dd>)^ 3050** 3051** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3052** <dd>The database is opened for reading and writing if possible, or reading 3053** only if the file is write protected by the operating system. In either 3054** case the database must already exist, otherwise an error is returned.</dd>)^ 3055** 3056** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3057** <dd>The database is opened for reading and writing, and is created if 3058** it does not already exist. This is the behavior that is always used for 3059** sqlite3_open() and sqlite3_open16().</dd>)^ 3060** </dl> 3061** 3062** If the 3rd parameter to sqlite3_open_v2() is not one of the 3063** combinations shown above optionally combined with other 3064** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3065** then the behavior is undefined. 3066** 3067** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 3068** opens in the multi-thread [threading mode] as long as the single-thread 3069** mode has not been set at compile-time or start-time. ^If the 3070** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 3071** in the serialized [threading mode] unless single-thread was 3072** previously selected at compile-time or start-time. 3073** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 3074** eligible to use [shared cache mode], regardless of whether or not shared 3075** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 3076** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 3077** participate in [shared cache mode] even if it is enabled. 3078** 3079** ^The fourth parameter to sqlite3_open_v2() is the name of the 3080** [sqlite3_vfs] object that defines the operating system interface that 3081** the new database connection should use. ^If the fourth parameter is 3082** a NULL pointer then the default [sqlite3_vfs] object is used. 3083** 3084** ^If the filename is ":memory:", then a private, temporary in-memory database 3085** is created for the connection. ^This in-memory database will vanish when 3086** the database connection is closed. Future versions of SQLite might 3087** make use of additional special filenames that begin with the ":" character. 3088** It is recommended that when a database filename actually does begin with 3089** a ":" character you should prefix the filename with a pathname such as 3090** "./" to avoid ambiguity. 3091** 3092** ^If the filename is an empty string, then a private, temporary 3093** on-disk database will be created. ^This private database will be 3094** automatically deleted as soon as the database connection is closed. 3095** 3096** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3097** 3098** ^If [URI filename] interpretation is enabled, and the filename argument 3099** begins with "file:", then the filename is interpreted as a URI. ^URI 3100** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3101** set in the fourth argument to sqlite3_open_v2(), or if it has 3102** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3103** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3104** As of SQLite version 3.7.7, URI filename interpretation is turned off 3105** by default, but future releases of SQLite might enable URI filename 3106** interpretation by default. See "[URI filenames]" for additional 3107** information. 3108** 3109** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3110** authority, then it must be either an empty string or the string 3111** "localhost". ^If the authority is not an empty string or "localhost", an 3112** error is returned to the caller. ^The fragment component of a URI, if 3113** present, is ignored. 3114** 3115** ^SQLite uses the path component of the URI as the name of the disk file 3116** which contains the database. ^If the path begins with a '/' character, 3117** then it is interpreted as an absolute path. ^If the path does not begin 3118** with a '/' (meaning that the authority section is omitted from the URI) 3119** then the path is interpreted as a relative path. 3120** ^(On windows, the first component of an absolute path 3121** is a drive specification (e.g. "C:").)^ 3122** 3123** [[core URI query parameters]] 3124** The query component of a URI may contain parameters that are interpreted 3125** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3126** SQLite and its built-in [VFSes] interpret the 3127** following query parameters: 3128** 3129** <ul> 3130** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3131** a VFS object that provides the operating system interface that should 3132** be used to access the database file on disk. ^If this option is set to 3133** an empty string the default VFS object is used. ^Specifying an unknown 3134** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3135** present, then the VFS specified by the option takes precedence over 3136** the value passed as the fourth parameter to sqlite3_open_v2(). 3137** 3138** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3139** "rwc", or "memory". Attempting to set it to any other value is 3140** an error)^. 3141** ^If "ro" is specified, then the database is opened for read-only 3142** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3143** third argument to sqlite3_open_v2(). ^If the mode option is set to 3144** "rw", then the database is opened for read-write (but not create) 3145** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3146** been set. ^Value "rwc" is equivalent to setting both 3147** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3148** set to "memory" then a pure [in-memory database] that never reads 3149** or writes from disk is used. ^It is an error to specify a value for 3150** the mode parameter that is less restrictive than that specified by 3151** the flags passed in the third parameter to sqlite3_open_v2(). 3152** 3153** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3154** "private". ^Setting it to "shared" is equivalent to setting the 3155** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3156** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3157** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3158** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3159** a URI filename, its value overrides any behavior requested by setting 3160** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3161** 3162** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3163** [powersafe overwrite] property does or does not apply to the 3164** storage media on which the database file resides. 3165** 3166** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3167** which if set disables file locking in rollback journal modes. This 3168** is useful for accessing a database on a filesystem that does not 3169** support locking. Caution: Database corruption might result if two 3170** or more processes write to the same database and any one of those 3171** processes uses nolock=1. 3172** 3173** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3174** parameter that indicates that the database file is stored on 3175** read-only media. ^When immutable is set, SQLite assumes that the 3176** database file cannot be changed, even by a process with higher 3177** privilege, and so the database is opened read-only and all locking 3178** and change detection is disabled. Caution: Setting the immutable 3179** property on a database file that does in fact change can result 3180** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3181** See also: [SQLITE_IOCAP_IMMUTABLE]. 3182** 3183** </ul> 3184** 3185** ^Specifying an unknown parameter in the query component of a URI is not an 3186** error. Future versions of SQLite might understand additional query 3187** parameters. See "[query parameters with special meaning to SQLite]" for 3188** additional information. 3189** 3190** [[URI filename examples]] <h3>URI filename examples</h3> 3191** 3192** <table border="1" align=center cellpadding=5> 3193** <tr><th> URI filenames <th> Results 3194** <tr><td> file:data.db <td> 3195** Open the file "data.db" in the current directory. 3196** <tr><td> file:/home/fred/data.db<br> 3197** file:///home/fred/data.db <br> 3198** file://localhost/home/fred/data.db <br> <td> 3199** Open the database file "/home/fred/data.db". 3200** <tr><td> file://darkstar/home/fred/data.db <td> 3201** An error. "darkstar" is not a recognized authority. 3202** <tr><td style="white-space:nowrap"> 3203** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3204** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3205** C:. Note that the %20 escaping in this example is not strictly 3206** necessary - space characters can be used literally 3207** in URI filenames. 3208** <tr><td> file:data.db?mode=ro&cache=private <td> 3209** Open file "data.db" in the current directory for read-only access. 3210** Regardless of whether or not shared-cache mode is enabled by 3211** default, use a private cache. 3212** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3213** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3214** that uses dot-files in place of posix advisory locking. 3215** <tr><td> file:data.db?mode=readonly <td> 3216** An error. "readonly" is not a valid option for the "mode" parameter. 3217** </table> 3218** 3219** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3220** query components of a URI. A hexadecimal escape sequence consists of a 3221** percent sign - "%" - followed by exactly two hexadecimal digits 3222** specifying an octet value. ^Before the path or query components of a 3223** URI filename are interpreted, they are encoded using UTF-8 and all 3224** hexadecimal escape sequences replaced by a single byte containing the 3225** corresponding octet. If this process generates an invalid UTF-8 encoding, 3226** the results are undefined. 3227** 3228** <b>Note to Windows users:</b> The encoding used for the filename argument 3229** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3230** codepage is currently defined. Filenames containing international 3231** characters must be converted to UTF-8 prior to passing them into 3232** sqlite3_open() or sqlite3_open_v2(). 3233** 3234** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3235** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3236** features that require the use of temporary files may fail. 3237** 3238** See also: [sqlite3_temp_directory] 3239*/ 3240int sqlite3_open( 3241 const char *filename, /* Database filename (UTF-8) */ 3242 sqlite3 **ppDb /* OUT: SQLite db handle */ 3243); 3244int sqlite3_open16( 3245 const void *filename, /* Database filename (UTF-16) */ 3246 sqlite3 **ppDb /* OUT: SQLite db handle */ 3247); 3248int sqlite3_open_v2( 3249 const char *filename, /* Database filename (UTF-8) */ 3250 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3251 int flags, /* Flags */ 3252 const char *zVfs /* Name of VFS module to use */ 3253); 3254 3255/* 3256** CAPI3REF: Obtain Values For URI Parameters 3257** 3258** These are utility routines, useful to VFS implementations, that check 3259** to see if a database file was a URI that contained a specific query 3260** parameter, and if so obtains the value of that query parameter. 3261** 3262** If F is the database filename pointer passed into the xOpen() method of 3263** a VFS implementation when the flags parameter to xOpen() has one or 3264** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3265** P is the name of the query parameter, then 3266** sqlite3_uri_parameter(F,P) returns the value of the P 3267** parameter if it exists or a NULL pointer if P does not appear as a 3268** query parameter on F. If P is a query parameter of F 3269** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3270** a pointer to an empty string. 3271** 3272** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3273** parameter and returns true (1) or false (0) according to the value 3274** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3275** value of query parameter P is one of "yes", "true", or "on" in any 3276** case or if the value begins with a non-zero number. The 3277** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3278** query parameter P is one of "no", "false", or "off" in any case or 3279** if the value begins with a numeric zero. If P is not a query 3280** parameter on F or if the value of P is does not match any of the 3281** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3282** 3283** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3284** 64-bit signed integer and returns that integer, or D if P does not 3285** exist. If the value of P is something other than an integer, then 3286** zero is returned. 3287** 3288** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3289** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3290** is not a database file pathname pointer that SQLite passed into the xOpen 3291** VFS method, then the behavior of this routine is undefined and probably 3292** undesirable. 3293*/ 3294const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3295int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3296sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3297 3298 3299/* 3300** CAPI3REF: Error Codes And Messages 3301** METHOD: sqlite3 3302** 3303** ^If the most recent sqlite3_* API call associated with 3304** [database connection] D failed, then the sqlite3_errcode(D) interface 3305** returns the numeric [result code] or [extended result code] for that 3306** API call. 3307** If the most recent API call was successful, 3308** then the return value from sqlite3_errcode() is undefined. 3309** ^The sqlite3_extended_errcode() 3310** interface is the same except that it always returns the 3311** [extended result code] even when extended result codes are 3312** disabled. 3313** 3314** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3315** text that describes the error, as either UTF-8 or UTF-16 respectively. 3316** ^(Memory to hold the error message string is managed internally. 3317** The application does not need to worry about freeing the result. 3318** However, the error string might be overwritten or deallocated by 3319** subsequent calls to other SQLite interface functions.)^ 3320** 3321** ^The sqlite3_errstr() interface returns the English-language text 3322** that describes the [result code], as UTF-8. 3323** ^(Memory to hold the error message string is managed internally 3324** and must not be freed by the application)^. 3325** 3326** When the serialized [threading mode] is in use, it might be the 3327** case that a second error occurs on a separate thread in between 3328** the time of the first error and the call to these interfaces. 3329** When that happens, the second error will be reported since these 3330** interfaces always report the most recent result. To avoid 3331** this, each thread can obtain exclusive use of the [database connection] D 3332** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3333** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3334** all calls to the interfaces listed here are completed. 3335** 3336** If an interface fails with SQLITE_MISUSE, that means the interface 3337** was invoked incorrectly by the application. In that case, the 3338** error code and message may or may not be set. 3339*/ 3340int sqlite3_errcode(sqlite3 *db); 3341int sqlite3_extended_errcode(sqlite3 *db); 3342const char *sqlite3_errmsg(sqlite3*); 3343const void *sqlite3_errmsg16(sqlite3*); 3344const char *sqlite3_errstr(int); 3345 3346/* 3347** CAPI3REF: Prepared Statement Object 3348** KEYWORDS: {prepared statement} {prepared statements} 3349** 3350** An instance of this object represents a single SQL statement that 3351** has been compiled into binary form and is ready to be evaluated. 3352** 3353** Think of each SQL statement as a separate computer program. The 3354** original SQL text is source code. A prepared statement object 3355** is the compiled object code. All SQL must be converted into a 3356** prepared statement before it can be run. 3357** 3358** The life-cycle of a prepared statement object usually goes like this: 3359** 3360** <ol> 3361** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3362** <li> Bind values to [parameters] using the sqlite3_bind_*() 3363** interfaces. 3364** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3365** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3366** to step 2. Do this zero or more times. 3367** <li> Destroy the object using [sqlite3_finalize()]. 3368** </ol> 3369*/ 3370typedef struct sqlite3_stmt sqlite3_stmt; 3371 3372/* 3373** CAPI3REF: Run-time Limits 3374** METHOD: sqlite3 3375** 3376** ^(This interface allows the size of various constructs to be limited 3377** on a connection by connection basis. The first parameter is the 3378** [database connection] whose limit is to be set or queried. The 3379** second parameter is one of the [limit categories] that define a 3380** class of constructs to be size limited. The third parameter is the 3381** new limit for that construct.)^ 3382** 3383** ^If the new limit is a negative number, the limit is unchanged. 3384** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3385** [limits | hard upper bound] 3386** set at compile-time by a C preprocessor macro called 3387** [limits | SQLITE_MAX_<i>NAME</i>]. 3388** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3389** ^Attempts to increase a limit above its hard upper bound are 3390** silently truncated to the hard upper bound. 3391** 3392** ^Regardless of whether or not the limit was changed, the 3393** [sqlite3_limit()] interface returns the prior value of the limit. 3394** ^Hence, to find the current value of a limit without changing it, 3395** simply invoke this interface with the third parameter set to -1. 3396** 3397** Run-time limits are intended for use in applications that manage 3398** both their own internal database and also databases that are controlled 3399** by untrusted external sources. An example application might be a 3400** web browser that has its own databases for storing history and 3401** separate databases controlled by JavaScript applications downloaded 3402** off the Internet. The internal databases can be given the 3403** large, default limits. Databases managed by external sources can 3404** be given much smaller limits designed to prevent a denial of service 3405** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3406** interface to further control untrusted SQL. The size of the database 3407** created by an untrusted script can be contained using the 3408** [max_page_count] [PRAGMA]. 3409** 3410** New run-time limit categories may be added in future releases. 3411*/ 3412int sqlite3_limit(sqlite3*, int id, int newVal); 3413 3414/* 3415** CAPI3REF: Run-Time Limit Categories 3416** KEYWORDS: {limit category} {*limit categories} 3417** 3418** These constants define various performance limits 3419** that can be lowered at run-time using [sqlite3_limit()]. 3420** The synopsis of the meanings of the various limits is shown below. 3421** Additional information is available at [limits | Limits in SQLite]. 3422** 3423** <dl> 3424** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3425** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3426** 3427** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3428** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3429** 3430** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3431** <dd>The maximum number of columns in a table definition or in the 3432** result set of a [SELECT] or the maximum number of columns in an index 3433** or in an ORDER BY or GROUP BY clause.</dd>)^ 3434** 3435** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3436** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3437** 3438** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3439** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3440** 3441** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3442** <dd>The maximum number of instructions in a virtual machine program 3443** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3444** the equivalent tries to allocate space for more than this many opcodes 3445** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3446** 3447** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3448** <dd>The maximum number of arguments on a function.</dd>)^ 3449** 3450** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3451** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3452** 3453** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3454** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3455** <dd>The maximum length of the pattern argument to the [LIKE] or 3456** [GLOB] operators.</dd>)^ 3457** 3458** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3459** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3460** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3461** 3462** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3463** <dd>The maximum depth of recursion for triggers.</dd>)^ 3464** 3465** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3466** <dd>The maximum number of auxiliary worker threads that a single 3467** [prepared statement] may start.</dd>)^ 3468** </dl> 3469*/ 3470#define SQLITE_LIMIT_LENGTH 0 3471#define SQLITE_LIMIT_SQL_LENGTH 1 3472#define SQLITE_LIMIT_COLUMN 2 3473#define SQLITE_LIMIT_EXPR_DEPTH 3 3474#define SQLITE_LIMIT_COMPOUND_SELECT 4 3475#define SQLITE_LIMIT_VDBE_OP 5 3476#define SQLITE_LIMIT_FUNCTION_ARG 6 3477#define SQLITE_LIMIT_ATTACHED 7 3478#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3479#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3480#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3481#define SQLITE_LIMIT_WORKER_THREADS 11 3482 3483 3484/* 3485** CAPI3REF: Compiling An SQL Statement 3486** KEYWORDS: {SQL statement compiler} 3487** METHOD: sqlite3 3488** CONSTRUCTOR: sqlite3_stmt 3489** 3490** To execute an SQL query, it must first be compiled into a byte-code 3491** program using one of these routines. 3492** 3493** The first argument, "db", is a [database connection] obtained from a 3494** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3495** [sqlite3_open16()]. The database connection must not have been closed. 3496** 3497** The second argument, "zSql", is the statement to be compiled, encoded 3498** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 3499** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 3500** use UTF-16. 3501** 3502** ^If the nByte argument is negative, then zSql is read up to the 3503** first zero terminator. ^If nByte is positive, then it is the 3504** number of bytes read from zSql. ^If nByte is zero, then no prepared 3505** statement is generated. 3506** If the caller knows that the supplied string is nul-terminated, then 3507** there is a small performance advantage to passing an nByte parameter that 3508** is the number of bytes in the input string <i>including</i> 3509** the nul-terminator. 3510** 3511** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3512** past the end of the first SQL statement in zSql. These routines only 3513** compile the first statement in zSql, so *pzTail is left pointing to 3514** what remains uncompiled. 3515** 3516** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3517** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3518** to NULL. ^If the input text contains no SQL (if the input is an empty 3519** string or a comment) then *ppStmt is set to NULL. 3520** The calling procedure is responsible for deleting the compiled 3521** SQL statement using [sqlite3_finalize()] after it has finished with it. 3522** ppStmt may not be NULL. 3523** 3524** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3525** otherwise an [error code] is returned. 3526** 3527** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 3528** recommended for all new programs. The two older interfaces are retained 3529** for backwards compatibility, but their use is discouraged. 3530** ^In the "v2" interfaces, the prepared statement 3531** that is returned (the [sqlite3_stmt] object) contains a copy of the 3532** original SQL text. This causes the [sqlite3_step()] interface to 3533** behave differently in three ways: 3534** 3535** <ol> 3536** <li> 3537** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3538** always used to do, [sqlite3_step()] will automatically recompile the SQL 3539** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3540** retries will occur before sqlite3_step() gives up and returns an error. 3541** </li> 3542** 3543** <li> 3544** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3545** [error codes] or [extended error codes]. ^The legacy behavior was that 3546** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3547** and the application would have to make a second call to [sqlite3_reset()] 3548** in order to find the underlying cause of the problem. With the "v2" prepare 3549** interfaces, the underlying reason for the error is returned immediately. 3550** </li> 3551** 3552** <li> 3553** ^If the specific value bound to [parameter | host parameter] in the 3554** WHERE clause might influence the choice of query plan for a statement, 3555** then the statement will be automatically recompiled, as if there had been 3556** a schema change, on the first [sqlite3_step()] call following any change 3557** to the [sqlite3_bind_text | bindings] of that [parameter]. 3558** ^The specific value of WHERE-clause [parameter] might influence the 3559** choice of query plan if the parameter is the left-hand side of a [LIKE] 3560** or [GLOB] operator or if the parameter is compared to an indexed column 3561** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3562** </li> 3563** </ol> 3564*/ 3565int sqlite3_prepare( 3566 sqlite3 *db, /* Database handle */ 3567 const char *zSql, /* SQL statement, UTF-8 encoded */ 3568 int nByte, /* Maximum length of zSql in bytes. */ 3569 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3570 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3571); 3572int sqlite3_prepare_v2( 3573 sqlite3 *db, /* Database handle */ 3574 const char *zSql, /* SQL statement, UTF-8 encoded */ 3575 int nByte, /* Maximum length of zSql in bytes. */ 3576 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3577 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3578); 3579int sqlite3_prepare16( 3580 sqlite3 *db, /* Database handle */ 3581 const void *zSql, /* SQL statement, UTF-16 encoded */ 3582 int nByte, /* Maximum length of zSql in bytes. */ 3583 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3584 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3585); 3586int sqlite3_prepare16_v2( 3587 sqlite3 *db, /* Database handle */ 3588 const void *zSql, /* SQL statement, UTF-16 encoded */ 3589 int nByte, /* Maximum length of zSql in bytes. */ 3590 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3591 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3592); 3593 3594/* 3595** CAPI3REF: Retrieving Statement SQL 3596** METHOD: sqlite3_stmt 3597** 3598** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 3599** SQL text used to create [prepared statement] P if P was 3600** created by either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 3601** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 3602** string containing the SQL text of prepared statement P with 3603** [bound parameters] expanded. 3604** 3605** ^(For example, if a prepared statement is created using the SQL 3606** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 3607** and parameter :xyz is unbound, then sqlite3_sql() will return 3608** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 3609** will return "SELECT 2345,NULL".)^ 3610** 3611** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 3612** is available to hold the result, or if the result would exceed the 3613** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 3614** 3615** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 3616** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 3617** option causes sqlite3_expanded_sql() to always return NULL. 3618** 3619** ^The string returned by sqlite3_sql(P) is managed by SQLite and is 3620** automatically freed when the prepared statement is finalized. 3621** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 3622** is obtained from [sqlite3_malloc()] and must be free by the application 3623** by passing it to [sqlite3_free()]. 3624*/ 3625const char *sqlite3_sql(sqlite3_stmt *pStmt); 3626char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 3627 3628/* 3629** CAPI3REF: Determine If An SQL Statement Writes The Database 3630** METHOD: sqlite3_stmt 3631** 3632** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3633** and only if the [prepared statement] X makes no direct changes to 3634** the content of the database file. 3635** 3636** Note that [application-defined SQL functions] or 3637** [virtual tables] might change the database indirectly as a side effect. 3638** ^(For example, if an application defines a function "eval()" that 3639** calls [sqlite3_exec()], then the following SQL statement would 3640** change the database file through side-effects: 3641** 3642** <blockquote><pre> 3643** SELECT eval('DELETE FROM t1') FROM t2; 3644** </pre></blockquote> 3645** 3646** But because the [SELECT] statement does not change the database file 3647** directly, sqlite3_stmt_readonly() would still return true.)^ 3648** 3649** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3650** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3651** since the statements themselves do not actually modify the database but 3652** rather they control the timing of when other statements modify the 3653** database. ^The [ATTACH] and [DETACH] statements also cause 3654** sqlite3_stmt_readonly() to return true since, while those statements 3655** change the configuration of a database connection, they do not make 3656** changes to the content of the database files on disk. 3657** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 3658** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 3659** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 3660** sqlite3_stmt_readonly() returns false for those commands. 3661*/ 3662int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3663 3664/* 3665** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3666** METHOD: sqlite3_stmt 3667** 3668** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3669** [prepared statement] S has been stepped at least once using 3670** [sqlite3_step(S)] but has neither run to completion (returned 3671** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3672** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3673** interface returns false if S is a NULL pointer. If S is not a 3674** NULL pointer and is not a pointer to a valid [prepared statement] 3675** object, then the behavior is undefined and probably undesirable. 3676** 3677** This interface can be used in combination [sqlite3_next_stmt()] 3678** to locate all prepared statements associated with a database 3679** connection that are in need of being reset. This can be used, 3680** for example, in diagnostic routines to search for prepared 3681** statements that are holding a transaction open. 3682*/ 3683int sqlite3_stmt_busy(sqlite3_stmt*); 3684 3685/* 3686** CAPI3REF: Dynamically Typed Value Object 3687** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3688** 3689** SQLite uses the sqlite3_value object to represent all values 3690** that can be stored in a database table. SQLite uses dynamic typing 3691** for the values it stores. ^Values stored in sqlite3_value objects 3692** can be integers, floating point values, strings, BLOBs, or NULL. 3693** 3694** An sqlite3_value object may be either "protected" or "unprotected". 3695** Some interfaces require a protected sqlite3_value. Other interfaces 3696** will accept either a protected or an unprotected sqlite3_value. 3697** Every interface that accepts sqlite3_value arguments specifies 3698** whether or not it requires a protected sqlite3_value. The 3699** [sqlite3_value_dup()] interface can be used to construct a new 3700** protected sqlite3_value from an unprotected sqlite3_value. 3701** 3702** The terms "protected" and "unprotected" refer to whether or not 3703** a mutex is held. An internal mutex is held for a protected 3704** sqlite3_value object but no mutex is held for an unprotected 3705** sqlite3_value object. If SQLite is compiled to be single-threaded 3706** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3707** or if SQLite is run in one of reduced mutex modes 3708** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3709** then there is no distinction between protected and unprotected 3710** sqlite3_value objects and they can be used interchangeably. However, 3711** for maximum code portability it is recommended that applications 3712** still make the distinction between protected and unprotected 3713** sqlite3_value objects even when not strictly required. 3714** 3715** ^The sqlite3_value objects that are passed as parameters into the 3716** implementation of [application-defined SQL functions] are protected. 3717** ^The sqlite3_value object returned by 3718** [sqlite3_column_value()] is unprotected. 3719** Unprotected sqlite3_value objects may only be used with 3720** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3721** The [sqlite3_value_blob | sqlite3_value_type()] family of 3722** interfaces require protected sqlite3_value objects. 3723*/ 3724typedef struct sqlite3_value sqlite3_value; 3725 3726/* 3727** CAPI3REF: SQL Function Context Object 3728** 3729** The context in which an SQL function executes is stored in an 3730** sqlite3_context object. ^A pointer to an sqlite3_context object 3731** is always first parameter to [application-defined SQL functions]. 3732** The application-defined SQL function implementation will pass this 3733** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3734** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3735** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3736** and/or [sqlite3_set_auxdata()]. 3737*/ 3738typedef struct sqlite3_context sqlite3_context; 3739 3740/* 3741** CAPI3REF: Binding Values To Prepared Statements 3742** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3743** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3744** METHOD: sqlite3_stmt 3745** 3746** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3747** literals may be replaced by a [parameter] that matches one of following 3748** templates: 3749** 3750** <ul> 3751** <li> ? 3752** <li> ?NNN 3753** <li> :VVV 3754** <li> @VVV 3755** <li> $VVV 3756** </ul> 3757** 3758** In the templates above, NNN represents an integer literal, 3759** and VVV represents an alphanumeric identifier.)^ ^The values of these 3760** parameters (also called "host parameter names" or "SQL parameters") 3761** can be set using the sqlite3_bind_*() routines defined here. 3762** 3763** ^The first argument to the sqlite3_bind_*() routines is always 3764** a pointer to the [sqlite3_stmt] object returned from 3765** [sqlite3_prepare_v2()] or its variants. 3766** 3767** ^The second argument is the index of the SQL parameter to be set. 3768** ^The leftmost SQL parameter has an index of 1. ^When the same named 3769** SQL parameter is used more than once, second and subsequent 3770** occurrences have the same index as the first occurrence. 3771** ^The index for named parameters can be looked up using the 3772** [sqlite3_bind_parameter_index()] API if desired. ^The index 3773** for "?NNN" parameters is the value of NNN. 3774** ^The NNN value must be between 1 and the [sqlite3_limit()] 3775** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3776** 3777** ^The third argument is the value to bind to the parameter. 3778** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3779** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3780** is ignored and the end result is the same as sqlite3_bind_null(). 3781** 3782** ^(In those routines that have a fourth argument, its value is the 3783** number of bytes in the parameter. To be clear: the value is the 3784** number of <u>bytes</u> in the value, not the number of characters.)^ 3785** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3786** is negative, then the length of the string is 3787** the number of bytes up to the first zero terminator. 3788** If the fourth parameter to sqlite3_bind_blob() is negative, then 3789** the behavior is undefined. 3790** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3791** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3792** that parameter must be the byte offset 3793** where the NUL terminator would occur assuming the string were NUL 3794** terminated. If any NUL characters occur at byte offsets less than 3795** the value of the fourth parameter then the resulting string value will 3796** contain embedded NULs. The result of expressions involving strings 3797** with embedded NULs is undefined. 3798** 3799** ^The fifth argument to the BLOB and string binding interfaces 3800** is a destructor used to dispose of the BLOB or 3801** string after SQLite has finished with it. ^The destructor is called 3802** to dispose of the BLOB or string even if the call to bind API fails. 3803** ^If the fifth argument is 3804** the special value [SQLITE_STATIC], then SQLite assumes that the 3805** information is in static, unmanaged space and does not need to be freed. 3806** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3807** SQLite makes its own private copy of the data immediately, before 3808** the sqlite3_bind_*() routine returns. 3809** 3810** ^The sixth argument to sqlite3_bind_text64() must be one of 3811** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3812** to specify the encoding of the text in the third parameter. If 3813** the sixth argument to sqlite3_bind_text64() is not one of the 3814** allowed values shown above, or if the text encoding is different 3815** from the encoding specified by the sixth parameter, then the behavior 3816** is undefined. 3817** 3818** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3819** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3820** (just an integer to hold its size) while it is being processed. 3821** Zeroblobs are intended to serve as placeholders for BLOBs whose 3822** content is later written using 3823** [sqlite3_blob_open | incremental BLOB I/O] routines. 3824** ^A negative value for the zeroblob results in a zero-length BLOB. 3825** 3826** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3827** for the [prepared statement] or with a prepared statement for which 3828** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3829** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3830** routine is passed a [prepared statement] that has been finalized, the 3831** result is undefined and probably harmful. 3832** 3833** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3834** ^Unbound parameters are interpreted as NULL. 3835** 3836** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3837** [error code] if anything goes wrong. 3838** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3839** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3840** [SQLITE_MAX_LENGTH]. 3841** ^[SQLITE_RANGE] is returned if the parameter 3842** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3843** 3844** See also: [sqlite3_bind_parameter_count()], 3845** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3846*/ 3847int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3848int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3849 void(*)(void*)); 3850int sqlite3_bind_double(sqlite3_stmt*, int, double); 3851int sqlite3_bind_int(sqlite3_stmt*, int, int); 3852int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3853int sqlite3_bind_null(sqlite3_stmt*, int); 3854int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3855int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3856int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3857 void(*)(void*), unsigned char encoding); 3858int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3859int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3860int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 3861 3862/* 3863** CAPI3REF: Number Of SQL Parameters 3864** METHOD: sqlite3_stmt 3865** 3866** ^This routine can be used to find the number of [SQL parameters] 3867** in a [prepared statement]. SQL parameters are tokens of the 3868** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3869** placeholders for values that are [sqlite3_bind_blob | bound] 3870** to the parameters at a later time. 3871** 3872** ^(This routine actually returns the index of the largest (rightmost) 3873** parameter. For all forms except ?NNN, this will correspond to the 3874** number of unique parameters. If parameters of the ?NNN form are used, 3875** there may be gaps in the list.)^ 3876** 3877** See also: [sqlite3_bind_blob|sqlite3_bind()], 3878** [sqlite3_bind_parameter_name()], and 3879** [sqlite3_bind_parameter_index()]. 3880*/ 3881int sqlite3_bind_parameter_count(sqlite3_stmt*); 3882 3883/* 3884** CAPI3REF: Name Of A Host Parameter 3885** METHOD: sqlite3_stmt 3886** 3887** ^The sqlite3_bind_parameter_name(P,N) interface returns 3888** the name of the N-th [SQL parameter] in the [prepared statement] P. 3889** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3890** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3891** respectively. 3892** In other words, the initial ":" or "$" or "@" or "?" 3893** is included as part of the name.)^ 3894** ^Parameters of the form "?" without a following integer have no name 3895** and are referred to as "nameless" or "anonymous parameters". 3896** 3897** ^The first host parameter has an index of 1, not 0. 3898** 3899** ^If the value N is out of range or if the N-th parameter is 3900** nameless, then NULL is returned. ^The returned string is 3901** always in UTF-8 encoding even if the named parameter was 3902** originally specified as UTF-16 in [sqlite3_prepare16()] or 3903** [sqlite3_prepare16_v2()]. 3904** 3905** See also: [sqlite3_bind_blob|sqlite3_bind()], 3906** [sqlite3_bind_parameter_count()], and 3907** [sqlite3_bind_parameter_index()]. 3908*/ 3909const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3910 3911/* 3912** CAPI3REF: Index Of A Parameter With A Given Name 3913** METHOD: sqlite3_stmt 3914** 3915** ^Return the index of an SQL parameter given its name. ^The 3916** index value returned is suitable for use as the second 3917** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3918** is returned if no matching parameter is found. ^The parameter 3919** name must be given in UTF-8 even if the original statement 3920** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3921** 3922** See also: [sqlite3_bind_blob|sqlite3_bind()], 3923** [sqlite3_bind_parameter_count()], and 3924** [sqlite3_bind_parameter_name()]. 3925*/ 3926int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3927 3928/* 3929** CAPI3REF: Reset All Bindings On A Prepared Statement 3930** METHOD: sqlite3_stmt 3931** 3932** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3933** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3934** ^Use this routine to reset all host parameters to NULL. 3935*/ 3936int sqlite3_clear_bindings(sqlite3_stmt*); 3937 3938/* 3939** CAPI3REF: Number Of Columns In A Result Set 3940** METHOD: sqlite3_stmt 3941** 3942** ^Return the number of columns in the result set returned by the 3943** [prepared statement]. ^If this routine returns 0, that means the 3944** [prepared statement] returns no data (for example an [UPDATE]). 3945** ^However, just because this routine returns a positive number does not 3946** mean that one or more rows of data will be returned. ^A SELECT statement 3947** will always have a positive sqlite3_column_count() but depending on the 3948** WHERE clause constraints and the table content, it might return no rows. 3949** 3950** See also: [sqlite3_data_count()] 3951*/ 3952int sqlite3_column_count(sqlite3_stmt *pStmt); 3953 3954/* 3955** CAPI3REF: Column Names In A Result Set 3956** METHOD: sqlite3_stmt 3957** 3958** ^These routines return the name assigned to a particular column 3959** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3960** interface returns a pointer to a zero-terminated UTF-8 string 3961** and sqlite3_column_name16() returns a pointer to a zero-terminated 3962** UTF-16 string. ^The first parameter is the [prepared statement] 3963** that implements the [SELECT] statement. ^The second parameter is the 3964** column number. ^The leftmost column is number 0. 3965** 3966** ^The returned string pointer is valid until either the [prepared statement] 3967** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3968** reprepared by the first call to [sqlite3_step()] for a particular run 3969** or until the next call to 3970** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3971** 3972** ^If sqlite3_malloc() fails during the processing of either routine 3973** (for example during a conversion from UTF-8 to UTF-16) then a 3974** NULL pointer is returned. 3975** 3976** ^The name of a result column is the value of the "AS" clause for 3977** that column, if there is an AS clause. If there is no AS clause 3978** then the name of the column is unspecified and may change from 3979** one release of SQLite to the next. 3980*/ 3981const char *sqlite3_column_name(sqlite3_stmt*, int N); 3982const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3983 3984/* 3985** CAPI3REF: Source Of Data In A Query Result 3986** METHOD: sqlite3_stmt 3987** 3988** ^These routines provide a means to determine the database, table, and 3989** table column that is the origin of a particular result column in 3990** [SELECT] statement. 3991** ^The name of the database or table or column can be returned as 3992** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3993** the database name, the _table_ routines return the table name, and 3994** the origin_ routines return the column name. 3995** ^The returned string is valid until the [prepared statement] is destroyed 3996** using [sqlite3_finalize()] or until the statement is automatically 3997** reprepared by the first call to [sqlite3_step()] for a particular run 3998** or until the same information is requested 3999** again in a different encoding. 4000** 4001** ^The names returned are the original un-aliased names of the 4002** database, table, and column. 4003** 4004** ^The first argument to these interfaces is a [prepared statement]. 4005** ^These functions return information about the Nth result column returned by 4006** the statement, where N is the second function argument. 4007** ^The left-most column is column 0 for these routines. 4008** 4009** ^If the Nth column returned by the statement is an expression or 4010** subquery and is not a column value, then all of these functions return 4011** NULL. ^These routine might also return NULL if a memory allocation error 4012** occurs. ^Otherwise, they return the name of the attached database, table, 4013** or column that query result column was extracted from. 4014** 4015** ^As with all other SQLite APIs, those whose names end with "16" return 4016** UTF-16 encoded strings and the other functions return UTF-8. 4017** 4018** ^These APIs are only available if the library was compiled with the 4019** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4020** 4021** If two or more threads call one or more of these routines against the same 4022** prepared statement and column at the same time then the results are 4023** undefined. 4024** 4025** If two or more threads call one or more 4026** [sqlite3_column_database_name | column metadata interfaces] 4027** for the same [prepared statement] and result column 4028** at the same time then the results are undefined. 4029*/ 4030const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4031const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4032const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4033const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4034const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4035const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4036 4037/* 4038** CAPI3REF: Declared Datatype Of A Query Result 4039** METHOD: sqlite3_stmt 4040** 4041** ^(The first parameter is a [prepared statement]. 4042** If this statement is a [SELECT] statement and the Nth column of the 4043** returned result set of that [SELECT] is a table column (not an 4044** expression or subquery) then the declared type of the table 4045** column is returned.)^ ^If the Nth column of the result set is an 4046** expression or subquery, then a NULL pointer is returned. 4047** ^The returned string is always UTF-8 encoded. 4048** 4049** ^(For example, given the database schema: 4050** 4051** CREATE TABLE t1(c1 VARIANT); 4052** 4053** and the following statement to be compiled: 4054** 4055** SELECT c1 + 1, c1 FROM t1; 4056** 4057** this routine would return the string "VARIANT" for the second result 4058** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4059** 4060** ^SQLite uses dynamic run-time typing. ^So just because a column 4061** is declared to contain a particular type does not mean that the 4062** data stored in that column is of the declared type. SQLite is 4063** strongly typed, but the typing is dynamic not static. ^Type 4064** is associated with individual values, not with the containers 4065** used to hold those values. 4066*/ 4067const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4068const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4069 4070/* 4071** CAPI3REF: Evaluate An SQL Statement 4072** METHOD: sqlite3_stmt 4073** 4074** After a [prepared statement] has been prepared using either 4075** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 4076** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4077** must be called one or more times to evaluate the statement. 4078** 4079** The details of the behavior of the sqlite3_step() interface depend 4080** on whether the statement was prepared using the newer "v2" interface 4081** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 4082** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4083** new "v2" interface is recommended for new applications but the legacy 4084** interface will continue to be supported. 4085** 4086** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4087** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4088** ^With the "v2" interface, any of the other [result codes] or 4089** [extended result codes] might be returned as well. 4090** 4091** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4092** database locks it needs to do its job. ^If the statement is a [COMMIT] 4093** or occurs outside of an explicit transaction, then you can retry the 4094** statement. If the statement is not a [COMMIT] and occurs within an 4095** explicit transaction then you should rollback the transaction before 4096** continuing. 4097** 4098** ^[SQLITE_DONE] means that the statement has finished executing 4099** successfully. sqlite3_step() should not be called again on this virtual 4100** machine without first calling [sqlite3_reset()] to reset the virtual 4101** machine back to its initial state. 4102** 4103** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4104** is returned each time a new row of data is ready for processing by the 4105** caller. The values may be accessed using the [column access functions]. 4106** sqlite3_step() is called again to retrieve the next row of data. 4107** 4108** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4109** violation) has occurred. sqlite3_step() should not be called again on 4110** the VM. More information may be found by calling [sqlite3_errmsg()]. 4111** ^With the legacy interface, a more specific error code (for example, 4112** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4113** can be obtained by calling [sqlite3_reset()] on the 4114** [prepared statement]. ^In the "v2" interface, 4115** the more specific error code is returned directly by sqlite3_step(). 4116** 4117** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4118** Perhaps it was called on a [prepared statement] that has 4119** already been [sqlite3_finalize | finalized] or on one that had 4120** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4121** be the case that the same database connection is being used by two or 4122** more threads at the same moment in time. 4123** 4124** For all versions of SQLite up to and including 3.6.23.1, a call to 4125** [sqlite3_reset()] was required after sqlite3_step() returned anything 4126** other than [SQLITE_ROW] before any subsequent invocation of 4127** sqlite3_step(). Failure to reset the prepared statement using 4128** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4129** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4130** sqlite3_step() began 4131** calling [sqlite3_reset()] automatically in this circumstance rather 4132** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4133** break because any application that ever receives an SQLITE_MISUSE error 4134** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4135** can be used to restore the legacy behavior. 4136** 4137** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4138** API always returns a generic error code, [SQLITE_ERROR], following any 4139** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4140** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4141** specific [error codes] that better describes the error. 4142** We admit that this is a goofy design. The problem has been fixed 4143** with the "v2" interface. If you prepare all of your SQL statements 4144** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 4145** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4146** then the more specific [error codes] are returned directly 4147** by sqlite3_step(). The use of the "v2" interface is recommended. 4148*/ 4149int sqlite3_step(sqlite3_stmt*); 4150 4151/* 4152** CAPI3REF: Number of columns in a result set 4153** METHOD: sqlite3_stmt 4154** 4155** ^The sqlite3_data_count(P) interface returns the number of columns in the 4156** current row of the result set of [prepared statement] P. 4157** ^If prepared statement P does not have results ready to return 4158** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 4159** interfaces) then sqlite3_data_count(P) returns 0. 4160** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4161** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4162** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4163** will return non-zero if previous call to [sqlite3_step](P) returned 4164** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4165** where it always returns zero since each step of that multi-step 4166** pragma returns 0 columns of data. 4167** 4168** See also: [sqlite3_column_count()] 4169*/ 4170int sqlite3_data_count(sqlite3_stmt *pStmt); 4171 4172/* 4173** CAPI3REF: Fundamental Datatypes 4174** KEYWORDS: SQLITE_TEXT 4175** 4176** ^(Every value in SQLite has one of five fundamental datatypes: 4177** 4178** <ul> 4179** <li> 64-bit signed integer 4180** <li> 64-bit IEEE floating point number 4181** <li> string 4182** <li> BLOB 4183** <li> NULL 4184** </ul>)^ 4185** 4186** These constants are codes for each of those types. 4187** 4188** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4189** for a completely different meaning. Software that links against both 4190** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4191** SQLITE_TEXT. 4192*/ 4193#define SQLITE_INTEGER 1 4194#define SQLITE_FLOAT 2 4195#define SQLITE_BLOB 4 4196#define SQLITE_NULL 5 4197#ifdef SQLITE_TEXT 4198# undef SQLITE_TEXT 4199#else 4200# define SQLITE_TEXT 3 4201#endif 4202#define SQLITE3_TEXT 3 4203 4204/* 4205** CAPI3REF: Result Values From A Query 4206** KEYWORDS: {column access functions} 4207** METHOD: sqlite3_stmt 4208** 4209** ^These routines return information about a single column of the current 4210** result row of a query. ^In every case the first argument is a pointer 4211** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4212** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4213** and the second argument is the index of the column for which information 4214** should be returned. ^The leftmost column of the result set has the index 0. 4215** ^The number of columns in the result can be determined using 4216** [sqlite3_column_count()]. 4217** 4218** If the SQL statement does not currently point to a valid row, or if the 4219** column index is out of range, the result is undefined. 4220** These routines may only be called when the most recent call to 4221** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4222** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4223** If any of these routines are called after [sqlite3_reset()] or 4224** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4225** something other than [SQLITE_ROW], the results are undefined. 4226** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4227** are called from a different thread while any of these routines 4228** are pending, then the results are undefined. 4229** 4230** ^The sqlite3_column_type() routine returns the 4231** [SQLITE_INTEGER | datatype code] for the initial data type 4232** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4233** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 4234** returned by sqlite3_column_type() is only meaningful if no type 4235** conversions have occurred as described below. After a type conversion, 4236** the value returned by sqlite3_column_type() is undefined. Future 4237** versions of SQLite may change the behavior of sqlite3_column_type() 4238** following a type conversion. 4239** 4240** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4241** routine returns the number of bytes in that BLOB or string. 4242** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4243** the string to UTF-8 and then returns the number of bytes. 4244** ^If the result is a numeric value then sqlite3_column_bytes() uses 4245** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4246** the number of bytes in that string. 4247** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4248** 4249** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4250** routine returns the number of bytes in that BLOB or string. 4251** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4252** the string to UTF-16 and then returns the number of bytes. 4253** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4254** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4255** the number of bytes in that string. 4256** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4257** 4258** ^The values returned by [sqlite3_column_bytes()] and 4259** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4260** of the string. ^For clarity: the values returned by 4261** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4262** bytes in the string, not the number of characters. 4263** 4264** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4265** even empty strings, are always zero-terminated. ^The return 4266** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4267** 4268** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4269** [unprotected sqlite3_value] object. In a multithreaded environment, 4270** an unprotected sqlite3_value object may only be used safely with 4271** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4272** If the [unprotected sqlite3_value] object returned by 4273** [sqlite3_column_value()] is used in any other way, including calls 4274** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4275** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4276** 4277** These routines attempt to convert the value where appropriate. ^For 4278** example, if the internal representation is FLOAT and a text result 4279** is requested, [sqlite3_snprintf()] is used internally to perform the 4280** conversion automatically. ^(The following table details the conversions 4281** that are applied: 4282** 4283** <blockquote> 4284** <table border="1"> 4285** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4286** 4287** <tr><td> NULL <td> INTEGER <td> Result is 0 4288** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4289** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4290** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4291** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4292** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4293** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4294** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4295** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4296** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4297** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4298** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4299** <tr><td> TEXT <td> BLOB <td> No change 4300** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4301** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4302** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4303** </table> 4304** </blockquote>)^ 4305** 4306** Note that when type conversions occur, pointers returned by prior 4307** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4308** sqlite3_column_text16() may be invalidated. 4309** Type conversions and pointer invalidations might occur 4310** in the following cases: 4311** 4312** <ul> 4313** <li> The initial content is a BLOB and sqlite3_column_text() or 4314** sqlite3_column_text16() is called. A zero-terminator might 4315** need to be added to the string.</li> 4316** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4317** sqlite3_column_text16() is called. The content must be converted 4318** to UTF-16.</li> 4319** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4320** sqlite3_column_text() is called. The content must be converted 4321** to UTF-8.</li> 4322** </ul> 4323** 4324** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4325** not invalidate a prior pointer, though of course the content of the buffer 4326** that the prior pointer references will have been modified. Other kinds 4327** of conversion are done in place when it is possible, but sometimes they 4328** are not possible and in those cases prior pointers are invalidated. 4329** 4330** The safest policy is to invoke these routines 4331** in one of the following ways: 4332** 4333** <ul> 4334** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4335** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4336** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4337** </ul> 4338** 4339** In other words, you should call sqlite3_column_text(), 4340** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4341** into the desired format, then invoke sqlite3_column_bytes() or 4342** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4343** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4344** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4345** with calls to sqlite3_column_bytes(). 4346** 4347** ^The pointers returned are valid until a type conversion occurs as 4348** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4349** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4350** and BLOBs is freed automatically. Do <em>not</em> pass the pointers returned 4351** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4352** [sqlite3_free()]. 4353** 4354** ^(If a memory allocation error occurs during the evaluation of any 4355** of these routines, a default value is returned. The default value 4356** is either the integer 0, the floating point number 0.0, or a NULL 4357** pointer. Subsequent calls to [sqlite3_errcode()] will return 4358** [SQLITE_NOMEM].)^ 4359*/ 4360const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4361int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4362int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4363double sqlite3_column_double(sqlite3_stmt*, int iCol); 4364int sqlite3_column_int(sqlite3_stmt*, int iCol); 4365sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4366const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4367const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4368int sqlite3_column_type(sqlite3_stmt*, int iCol); 4369sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4370 4371/* 4372** CAPI3REF: Destroy A Prepared Statement Object 4373** DESTRUCTOR: sqlite3_stmt 4374** 4375** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4376** ^If the most recent evaluation of the statement encountered no errors 4377** or if the statement is never been evaluated, then sqlite3_finalize() returns 4378** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4379** sqlite3_finalize(S) returns the appropriate [error code] or 4380** [extended error code]. 4381** 4382** ^The sqlite3_finalize(S) routine can be called at any point during 4383** the life cycle of [prepared statement] S: 4384** before statement S is ever evaluated, after 4385** one or more calls to [sqlite3_reset()], or after any call 4386** to [sqlite3_step()] regardless of whether or not the statement has 4387** completed execution. 4388** 4389** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4390** 4391** The application must finalize every [prepared statement] in order to avoid 4392** resource leaks. It is a grievous error for the application to try to use 4393** a prepared statement after it has been finalized. Any use of a prepared 4394** statement after it has been finalized can result in undefined and 4395** undesirable behavior such as segfaults and heap corruption. 4396*/ 4397int sqlite3_finalize(sqlite3_stmt *pStmt); 4398 4399/* 4400** CAPI3REF: Reset A Prepared Statement Object 4401** METHOD: sqlite3_stmt 4402** 4403** The sqlite3_reset() function is called to reset a [prepared statement] 4404** object back to its initial state, ready to be re-executed. 4405** ^Any SQL statement variables that had values bound to them using 4406** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4407** Use [sqlite3_clear_bindings()] to reset the bindings. 4408** 4409** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4410** back to the beginning of its program. 4411** 4412** ^If the most recent call to [sqlite3_step(S)] for the 4413** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4414** or if [sqlite3_step(S)] has never before been called on S, 4415** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4416** 4417** ^If the most recent call to [sqlite3_step(S)] for the 4418** [prepared statement] S indicated an error, then 4419** [sqlite3_reset(S)] returns an appropriate [error code]. 4420** 4421** ^The [sqlite3_reset(S)] interface does not change the values 4422** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4423*/ 4424int sqlite3_reset(sqlite3_stmt *pStmt); 4425 4426/* 4427** CAPI3REF: Create Or Redefine SQL Functions 4428** KEYWORDS: {function creation routines} 4429** KEYWORDS: {application-defined SQL function} 4430** KEYWORDS: {application-defined SQL functions} 4431** METHOD: sqlite3 4432** 4433** ^These functions (collectively known as "function creation routines") 4434** are used to add SQL functions or aggregates or to redefine the behavior 4435** of existing SQL functions or aggregates. The only differences between 4436** these routines are the text encoding expected for 4437** the second parameter (the name of the function being created) 4438** and the presence or absence of a destructor callback for 4439** the application data pointer. 4440** 4441** ^The first parameter is the [database connection] to which the SQL 4442** function is to be added. ^If an application uses more than one database 4443** connection then application-defined SQL functions must be added 4444** to each database connection separately. 4445** 4446** ^The second parameter is the name of the SQL function to be created or 4447** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4448** representation, exclusive of the zero-terminator. ^Note that the name 4449** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4450** ^Any attempt to create a function with a longer name 4451** will result in [SQLITE_MISUSE] being returned. 4452** 4453** ^The third parameter (nArg) 4454** is the number of arguments that the SQL function or 4455** aggregate takes. ^If this parameter is -1, then the SQL function or 4456** aggregate may take any number of arguments between 0 and the limit 4457** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4458** parameter is less than -1 or greater than 127 then the behavior is 4459** undefined. 4460** 4461** ^The fourth parameter, eTextRep, specifies what 4462** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4463** its parameters. The application should set this parameter to 4464** [SQLITE_UTF16LE] if the function implementation invokes 4465** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4466** implementation invokes [sqlite3_value_text16be()] on an input, or 4467** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4468** otherwise. ^The same SQL function may be registered multiple times using 4469** different preferred text encodings, with different implementations for 4470** each encoding. 4471** ^When multiple implementations of the same function are available, SQLite 4472** will pick the one that involves the least amount of data conversion. 4473** 4474** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4475** to signal that the function will always return the same result given 4476** the same inputs within a single SQL statement. Most SQL functions are 4477** deterministic. The built-in [random()] SQL function is an example of a 4478** function that is not deterministic. The SQLite query planner is able to 4479** perform additional optimizations on deterministic functions, so use 4480** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4481** 4482** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4483** function can gain access to this pointer using [sqlite3_user_data()].)^ 4484** 4485** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4486** pointers to C-language functions that implement the SQL function or 4487** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4488** callback only; NULL pointers must be passed as the xStep and xFinal 4489** parameters. ^An aggregate SQL function requires an implementation of xStep 4490** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4491** SQL function or aggregate, pass NULL pointers for all three function 4492** callbacks. 4493** 4494** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4495** then it is destructor for the application data pointer. 4496** The destructor is invoked when the function is deleted, either by being 4497** overloaded or when the database connection closes.)^ 4498** ^The destructor is also invoked if the call to 4499** sqlite3_create_function_v2() fails. 4500** ^When the destructor callback of the tenth parameter is invoked, it 4501** is passed a single argument which is a copy of the application data 4502** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4503** 4504** ^It is permitted to register multiple implementations of the same 4505** functions with the same name but with either differing numbers of 4506** arguments or differing preferred text encodings. ^SQLite will use 4507** the implementation that most closely matches the way in which the 4508** SQL function is used. ^A function implementation with a non-negative 4509** nArg parameter is a better match than a function implementation with 4510** a negative nArg. ^A function where the preferred text encoding 4511** matches the database encoding is a better 4512** match than a function where the encoding is different. 4513** ^A function where the encoding difference is between UTF16le and UTF16be 4514** is a closer match than a function where the encoding difference is 4515** between UTF8 and UTF16. 4516** 4517** ^Built-in functions may be overloaded by new application-defined functions. 4518** 4519** ^An application-defined function is permitted to call other 4520** SQLite interfaces. However, such calls must not 4521** close the database connection nor finalize or reset the prepared 4522** statement in which the function is running. 4523*/ 4524int sqlite3_create_function( 4525 sqlite3 *db, 4526 const char *zFunctionName, 4527 int nArg, 4528 int eTextRep, 4529 void *pApp, 4530 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4531 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4532 void (*xFinal)(sqlite3_context*) 4533); 4534int sqlite3_create_function16( 4535 sqlite3 *db, 4536 const void *zFunctionName, 4537 int nArg, 4538 int eTextRep, 4539 void *pApp, 4540 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4541 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4542 void (*xFinal)(sqlite3_context*) 4543); 4544int sqlite3_create_function_v2( 4545 sqlite3 *db, 4546 const char *zFunctionName, 4547 int nArg, 4548 int eTextRep, 4549 void *pApp, 4550 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4551 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4552 void (*xFinal)(sqlite3_context*), 4553 void(*xDestroy)(void*) 4554); 4555 4556/* 4557** CAPI3REF: Text Encodings 4558** 4559** These constant define integer codes that represent the various 4560** text encodings supported by SQLite. 4561*/ 4562#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4563#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4564#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4565#define SQLITE_UTF16 4 /* Use native byte order */ 4566#define SQLITE_ANY 5 /* Deprecated */ 4567#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4568 4569/* 4570** CAPI3REF: Function Flags 4571** 4572** These constants may be ORed together with the 4573** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4574** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4575** [sqlite3_create_function_v2()]. 4576*/ 4577#define SQLITE_DETERMINISTIC 0x800 4578 4579/* 4580** CAPI3REF: Deprecated Functions 4581** DEPRECATED 4582** 4583** These functions are [deprecated]. In order to maintain 4584** backwards compatibility with older code, these functions continue 4585** to be supported. However, new applications should avoid 4586** the use of these functions. To encourage programmers to avoid 4587** these functions, we will not explain what they do. 4588*/ 4589#ifndef SQLITE_OMIT_DEPRECATED 4590SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4591SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4592SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4593SQLITE_DEPRECATED int sqlite3_global_recover(void); 4594SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4595SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4596 void*,sqlite3_int64); 4597#endif 4598 4599/* 4600** CAPI3REF: Obtaining SQL Values 4601** METHOD: sqlite3_value 4602** 4603** The C-language implementation of SQL functions and aggregates uses 4604** this set of interface routines to access the parameter values on 4605** the function or aggregate. 4606** 4607** The xFunc (for scalar functions) or xStep (for aggregates) parameters 4608** to [sqlite3_create_function()] and [sqlite3_create_function16()] 4609** define callbacks that implement the SQL functions and aggregates. 4610** The 3rd parameter to these callbacks is an array of pointers to 4611** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 4612** each parameter to the SQL function. These routines are used to 4613** extract values from the [sqlite3_value] objects. 4614** 4615** These routines work only with [protected sqlite3_value] objects. 4616** Any attempt to use these routines on an [unprotected sqlite3_value] 4617** object results in undefined behavior. 4618** 4619** ^These routines work just like the corresponding [column access functions] 4620** except that these routines take a single [protected sqlite3_value] object 4621** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4622** 4623** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4624** in the native byte-order of the host machine. ^The 4625** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4626** extract UTF-16 strings as big-endian and little-endian respectively. 4627** 4628** ^(The sqlite3_value_numeric_type() interface attempts to apply 4629** numeric affinity to the value. This means that an attempt is 4630** made to convert the value to an integer or floating point. If 4631** such a conversion is possible without loss of information (in other 4632** words, if the value is a string that looks like a number) 4633** then the conversion is performed. Otherwise no conversion occurs. 4634** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4635** 4636** Please pay particular attention to the fact that the pointer returned 4637** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4638** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4639** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4640** or [sqlite3_value_text16()]. 4641** 4642** These routines must be called from the same thread as 4643** the SQL function that supplied the [sqlite3_value*] parameters. 4644*/ 4645const void *sqlite3_value_blob(sqlite3_value*); 4646int sqlite3_value_bytes(sqlite3_value*); 4647int sqlite3_value_bytes16(sqlite3_value*); 4648double sqlite3_value_double(sqlite3_value*); 4649int sqlite3_value_int(sqlite3_value*); 4650sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4651const unsigned char *sqlite3_value_text(sqlite3_value*); 4652const void *sqlite3_value_text16(sqlite3_value*); 4653const void *sqlite3_value_text16le(sqlite3_value*); 4654const void *sqlite3_value_text16be(sqlite3_value*); 4655int sqlite3_value_type(sqlite3_value*); 4656int sqlite3_value_numeric_type(sqlite3_value*); 4657 4658/* 4659** CAPI3REF: Finding The Subtype Of SQL Values 4660** METHOD: sqlite3_value 4661** 4662** The sqlite3_value_subtype(V) function returns the subtype for 4663** an [application-defined SQL function] argument V. The subtype 4664** information can be used to pass a limited amount of context from 4665** one SQL function to another. Use the [sqlite3_result_subtype()] 4666** routine to set the subtype for the return value of an SQL function. 4667** 4668** SQLite makes no use of subtype itself. It merely passes the subtype 4669** from the result of one [application-defined SQL function] into the 4670** input of another. 4671*/ 4672unsigned int sqlite3_value_subtype(sqlite3_value*); 4673 4674/* 4675** CAPI3REF: Copy And Free SQL Values 4676** METHOD: sqlite3_value 4677** 4678** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 4679** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 4680** is a [protected sqlite3_value] object even if the input is not. 4681** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 4682** memory allocation fails. 4683** 4684** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 4685** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 4686** then sqlite3_value_free(V) is a harmless no-op. 4687*/ 4688sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 4689void sqlite3_value_free(sqlite3_value*); 4690 4691/* 4692** CAPI3REF: Obtain Aggregate Function Context 4693** METHOD: sqlite3_context 4694** 4695** Implementations of aggregate SQL functions use this 4696** routine to allocate memory for storing their state. 4697** 4698** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4699** for a particular aggregate function, SQLite 4700** allocates N of memory, zeroes out that memory, and returns a pointer 4701** to the new memory. ^On second and subsequent calls to 4702** sqlite3_aggregate_context() for the same aggregate function instance, 4703** the same buffer is returned. Sqlite3_aggregate_context() is normally 4704** called once for each invocation of the xStep callback and then one 4705** last time when the xFinal callback is invoked. ^(When no rows match 4706** an aggregate query, the xStep() callback of the aggregate function 4707** implementation is never called and xFinal() is called exactly once. 4708** In those cases, sqlite3_aggregate_context() might be called for the 4709** first time from within xFinal().)^ 4710** 4711** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4712** when first called if N is less than or equal to zero or if a memory 4713** allocate error occurs. 4714** 4715** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4716** determined by the N parameter on first successful call. Changing the 4717** value of N in subsequent call to sqlite3_aggregate_context() within 4718** the same aggregate function instance will not resize the memory 4719** allocation.)^ Within the xFinal callback, it is customary to set 4720** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4721** pointless memory allocations occur. 4722** 4723** ^SQLite automatically frees the memory allocated by 4724** sqlite3_aggregate_context() when the aggregate query concludes. 4725** 4726** The first parameter must be a copy of the 4727** [sqlite3_context | SQL function context] that is the first parameter 4728** to the xStep or xFinal callback routine that implements the aggregate 4729** function. 4730** 4731** This routine must be called from the same thread in which 4732** the aggregate SQL function is running. 4733*/ 4734void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4735 4736/* 4737** CAPI3REF: User Data For Functions 4738** METHOD: sqlite3_context 4739** 4740** ^The sqlite3_user_data() interface returns a copy of 4741** the pointer that was the pUserData parameter (the 5th parameter) 4742** of the [sqlite3_create_function()] 4743** and [sqlite3_create_function16()] routines that originally 4744** registered the application defined function. 4745** 4746** This routine must be called from the same thread in which 4747** the application-defined function is running. 4748*/ 4749void *sqlite3_user_data(sqlite3_context*); 4750 4751/* 4752** CAPI3REF: Database Connection For Functions 4753** METHOD: sqlite3_context 4754** 4755** ^The sqlite3_context_db_handle() interface returns a copy of 4756** the pointer to the [database connection] (the 1st parameter) 4757** of the [sqlite3_create_function()] 4758** and [sqlite3_create_function16()] routines that originally 4759** registered the application defined function. 4760*/ 4761sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4762 4763/* 4764** CAPI3REF: Function Auxiliary Data 4765** METHOD: sqlite3_context 4766** 4767** These functions may be used by (non-aggregate) SQL functions to 4768** associate metadata with argument values. If the same value is passed to 4769** multiple invocations of the same SQL function during query execution, under 4770** some circumstances the associated metadata may be preserved. An example 4771** of where this might be useful is in a regular-expression matching 4772** function. The compiled version of the regular expression can be stored as 4773** metadata associated with the pattern string. 4774** Then as long as the pattern string remains the same, 4775** the compiled regular expression can be reused on multiple 4776** invocations of the same function. 4777** 4778** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 4779** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 4780** value to the application-defined function. ^N is zero for the left-most 4781** function argument. ^If there is no metadata 4782** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 4783** returns a NULL pointer. 4784** 4785** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4786** argument of the application-defined function. ^Subsequent 4787** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4788** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4789** NULL if the metadata has been discarded. 4790** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4791** SQLite will invoke the destructor function X with parameter P exactly 4792** once, when the metadata is discarded. 4793** SQLite is free to discard the metadata at any time, including: <ul> 4794** <li> ^(when the corresponding function parameter changes)^, or 4795** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4796** SQL statement)^, or 4797** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 4798** parameter)^, or 4799** <li> ^(during the original sqlite3_set_auxdata() call when a memory 4800** allocation error occurs.)^ </ul> 4801** 4802** Note the last bullet in particular. The destructor X in 4803** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 4804** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 4805** should be called near the end of the function implementation and the 4806** function implementation should not make any use of P after 4807** sqlite3_set_auxdata() has been called. 4808** 4809** ^(In practice, metadata is preserved between function calls for 4810** function parameters that are compile-time constants, including literal 4811** values and [parameters] and expressions composed from the same.)^ 4812** 4813** The value of the N parameter to these interfaces should be non-negative. 4814** Future enhancements may make use of negative N values to define new 4815** kinds of function caching behavior. 4816** 4817** These routines must be called from the same thread in which 4818** the SQL function is running. 4819*/ 4820void *sqlite3_get_auxdata(sqlite3_context*, int N); 4821void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4822 4823 4824/* 4825** CAPI3REF: Constants Defining Special Destructor Behavior 4826** 4827** These are special values for the destructor that is passed in as the 4828** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4829** argument is SQLITE_STATIC, it means that the content pointer is constant 4830** and will never change. It does not need to be destroyed. ^The 4831** SQLITE_TRANSIENT value means that the content will likely change in 4832** the near future and that SQLite should make its own private copy of 4833** the content before returning. 4834** 4835** The typedef is necessary to work around problems in certain 4836** C++ compilers. 4837*/ 4838typedef void (*sqlite3_destructor_type)(void*); 4839#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4840#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4841 4842/* 4843** CAPI3REF: Setting The Result Of An SQL Function 4844** METHOD: sqlite3_context 4845** 4846** These routines are used by the xFunc or xFinal callbacks that 4847** implement SQL functions and aggregates. See 4848** [sqlite3_create_function()] and [sqlite3_create_function16()] 4849** for additional information. 4850** 4851** These functions work very much like the [parameter binding] family of 4852** functions used to bind values to host parameters in prepared statements. 4853** Refer to the [SQL parameter] documentation for additional information. 4854** 4855** ^The sqlite3_result_blob() interface sets the result from 4856** an application-defined function to be the BLOB whose content is pointed 4857** to by the second parameter and which is N bytes long where N is the 4858** third parameter. 4859** 4860** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 4861** interfaces set the result of the application-defined function to be 4862** a BLOB containing all zero bytes and N bytes in size. 4863** 4864** ^The sqlite3_result_double() interface sets the result from 4865** an application-defined function to be a floating point value specified 4866** by its 2nd argument. 4867** 4868** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4869** cause the implemented SQL function to throw an exception. 4870** ^SQLite uses the string pointed to by the 4871** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4872** as the text of an error message. ^SQLite interprets the error 4873** message string from sqlite3_result_error() as UTF-8. ^SQLite 4874** interprets the string from sqlite3_result_error16() as UTF-16 in native 4875** byte order. ^If the third parameter to sqlite3_result_error() 4876** or sqlite3_result_error16() is negative then SQLite takes as the error 4877** message all text up through the first zero character. 4878** ^If the third parameter to sqlite3_result_error() or 4879** sqlite3_result_error16() is non-negative then SQLite takes that many 4880** bytes (not characters) from the 2nd parameter as the error message. 4881** ^The sqlite3_result_error() and sqlite3_result_error16() 4882** routines make a private copy of the error message text before 4883** they return. Hence, the calling function can deallocate or 4884** modify the text after they return without harm. 4885** ^The sqlite3_result_error_code() function changes the error code 4886** returned by SQLite as a result of an error in a function. ^By default, 4887** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4888** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4889** 4890** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 4891** error indicating that a string or BLOB is too long to represent. 4892** 4893** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 4894** error indicating that a memory allocation failed. 4895** 4896** ^The sqlite3_result_int() interface sets the return value 4897** of the application-defined function to be the 32-bit signed integer 4898** value given in the 2nd argument. 4899** ^The sqlite3_result_int64() interface sets the return value 4900** of the application-defined function to be the 64-bit signed integer 4901** value given in the 2nd argument. 4902** 4903** ^The sqlite3_result_null() interface sets the return value 4904** of the application-defined function to be NULL. 4905** 4906** ^The sqlite3_result_text(), sqlite3_result_text16(), 4907** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4908** set the return value of the application-defined function to be 4909** a text string which is represented as UTF-8, UTF-16 native byte order, 4910** UTF-16 little endian, or UTF-16 big endian, respectively. 4911** ^The sqlite3_result_text64() interface sets the return value of an 4912** application-defined function to be a text string in an encoding 4913** specified by the fifth (and last) parameter, which must be one 4914** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 4915** ^SQLite takes the text result from the application from 4916** the 2nd parameter of the sqlite3_result_text* interfaces. 4917** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4918** is negative, then SQLite takes result text from the 2nd parameter 4919** through the first zero character. 4920** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4921** is non-negative, then as many bytes (not characters) of the text 4922** pointed to by the 2nd parameter are taken as the application-defined 4923** function result. If the 3rd parameter is non-negative, then it 4924** must be the byte offset into the string where the NUL terminator would 4925** appear if the string where NUL terminated. If any NUL characters occur 4926** in the string at a byte offset that is less than the value of the 3rd 4927** parameter, then the resulting string will contain embedded NULs and the 4928** result of expressions operating on strings with embedded NULs is undefined. 4929** ^If the 4th parameter to the sqlite3_result_text* interfaces 4930** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4931** function as the destructor on the text or BLOB result when it has 4932** finished using that result. 4933** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4934** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4935** assumes that the text or BLOB result is in constant space and does not 4936** copy the content of the parameter nor call a destructor on the content 4937** when it has finished using that result. 4938** ^If the 4th parameter to the sqlite3_result_text* interfaces 4939** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4940** then SQLite makes a copy of the result into space obtained from 4941** from [sqlite3_malloc()] before it returns. 4942** 4943** ^The sqlite3_result_value() interface sets the result of 4944** the application-defined function to be a copy of the 4945** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4946** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4947** so that the [sqlite3_value] specified in the parameter may change or 4948** be deallocated after sqlite3_result_value() returns without harm. 4949** ^A [protected sqlite3_value] object may always be used where an 4950** [unprotected sqlite3_value] object is required, so either 4951** kind of [sqlite3_value] object can be used with this interface. 4952** 4953** If these routines are called from within the different thread 4954** than the one containing the application-defined function that received 4955** the [sqlite3_context] pointer, the results are undefined. 4956*/ 4957void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4958void sqlite3_result_blob64(sqlite3_context*,const void*, 4959 sqlite3_uint64,void(*)(void*)); 4960void sqlite3_result_double(sqlite3_context*, double); 4961void sqlite3_result_error(sqlite3_context*, const char*, int); 4962void sqlite3_result_error16(sqlite3_context*, const void*, int); 4963void sqlite3_result_error_toobig(sqlite3_context*); 4964void sqlite3_result_error_nomem(sqlite3_context*); 4965void sqlite3_result_error_code(sqlite3_context*, int); 4966void sqlite3_result_int(sqlite3_context*, int); 4967void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4968void sqlite3_result_null(sqlite3_context*); 4969void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4970void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 4971 void(*)(void*), unsigned char encoding); 4972void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4973void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4974void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4975void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4976void sqlite3_result_zeroblob(sqlite3_context*, int n); 4977int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 4978 4979 4980/* 4981** CAPI3REF: Setting The Subtype Of An SQL Function 4982** METHOD: sqlite3_context 4983** 4984** The sqlite3_result_subtype(C,T) function causes the subtype of 4985** the result from the [application-defined SQL function] with 4986** [sqlite3_context] C to be the value T. Only the lower 8 bits 4987** of the subtype T are preserved in current versions of SQLite; 4988** higher order bits are discarded. 4989** The number of subtype bytes preserved by SQLite might increase 4990** in future releases of SQLite. 4991*/ 4992void sqlite3_result_subtype(sqlite3_context*,unsigned int); 4993 4994/* 4995** CAPI3REF: Define New Collating Sequences 4996** METHOD: sqlite3 4997** 4998** ^These functions add, remove, or modify a [collation] associated 4999** with the [database connection] specified as the first argument. 5000** 5001** ^The name of the collation is a UTF-8 string 5002** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5003** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5004** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5005** considered to be the same name. 5006** 5007** ^(The third argument (eTextRep) must be one of the constants: 5008** <ul> 5009** <li> [SQLITE_UTF8], 5010** <li> [SQLITE_UTF16LE], 5011** <li> [SQLITE_UTF16BE], 5012** <li> [SQLITE_UTF16], or 5013** <li> [SQLITE_UTF16_ALIGNED]. 5014** </ul>)^ 5015** ^The eTextRep argument determines the encoding of strings passed 5016** to the collating function callback, xCallback. 5017** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5018** force strings to be UTF16 with native byte order. 5019** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5020** on an even byte address. 5021** 5022** ^The fourth argument, pArg, is an application data pointer that is passed 5023** through as the first argument to the collating function callback. 5024** 5025** ^The fifth argument, xCallback, is a pointer to the collating function. 5026** ^Multiple collating functions can be registered using the same name but 5027** with different eTextRep parameters and SQLite will use whichever 5028** function requires the least amount of data transformation. 5029** ^If the xCallback argument is NULL then the collating function is 5030** deleted. ^When all collating functions having the same name are deleted, 5031** that collation is no longer usable. 5032** 5033** ^The collating function callback is invoked with a copy of the pArg 5034** application data pointer and with two strings in the encoding specified 5035** by the eTextRep argument. The collating function must return an 5036** integer that is negative, zero, or positive 5037** if the first string is less than, equal to, or greater than the second, 5038** respectively. A collating function must always return the same answer 5039** given the same inputs. If two or more collating functions are registered 5040** to the same collation name (using different eTextRep values) then all 5041** must give an equivalent answer when invoked with equivalent strings. 5042** The collating function must obey the following properties for all 5043** strings A, B, and C: 5044** 5045** <ol> 5046** <li> If A==B then B==A. 5047** <li> If A==B and B==C then A==C. 5048** <li> If A<B THEN B>A. 5049** <li> If A<B and B<C then A<C. 5050** </ol> 5051** 5052** If a collating function fails any of the above constraints and that 5053** collating function is registered and used, then the behavior of SQLite 5054** is undefined. 5055** 5056** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5057** with the addition that the xDestroy callback is invoked on pArg when 5058** the collating function is deleted. 5059** ^Collating functions are deleted when they are overridden by later 5060** calls to the collation creation functions or when the 5061** [database connection] is closed using [sqlite3_close()]. 5062** 5063** ^The xDestroy callback is <u>not</u> called if the 5064** sqlite3_create_collation_v2() function fails. Applications that invoke 5065** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5066** check the return code and dispose of the application data pointer 5067** themselves rather than expecting SQLite to deal with it for them. 5068** This is different from every other SQLite interface. The inconsistency 5069** is unfortunate but cannot be changed without breaking backwards 5070** compatibility. 5071** 5072** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5073*/ 5074int sqlite3_create_collation( 5075 sqlite3*, 5076 const char *zName, 5077 int eTextRep, 5078 void *pArg, 5079 int(*xCompare)(void*,int,const void*,int,const void*) 5080); 5081int sqlite3_create_collation_v2( 5082 sqlite3*, 5083 const char *zName, 5084 int eTextRep, 5085 void *pArg, 5086 int(*xCompare)(void*,int,const void*,int,const void*), 5087 void(*xDestroy)(void*) 5088); 5089int sqlite3_create_collation16( 5090 sqlite3*, 5091 const void *zName, 5092 int eTextRep, 5093 void *pArg, 5094 int(*xCompare)(void*,int,const void*,int,const void*) 5095); 5096 5097/* 5098** CAPI3REF: Collation Needed Callbacks 5099** METHOD: sqlite3 5100** 5101** ^To avoid having to register all collation sequences before a database 5102** can be used, a single callback function may be registered with the 5103** [database connection] to be invoked whenever an undefined collation 5104** sequence is required. 5105** 5106** ^If the function is registered using the sqlite3_collation_needed() API, 5107** then it is passed the names of undefined collation sequences as strings 5108** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5109** the names are passed as UTF-16 in machine native byte order. 5110** ^A call to either function replaces the existing collation-needed callback. 5111** 5112** ^(When the callback is invoked, the first argument passed is a copy 5113** of the second argument to sqlite3_collation_needed() or 5114** sqlite3_collation_needed16(). The second argument is the database 5115** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5116** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5117** sequence function required. The fourth parameter is the name of the 5118** required collation sequence.)^ 5119** 5120** The callback function should register the desired collation using 5121** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5122** [sqlite3_create_collation_v2()]. 5123*/ 5124int sqlite3_collation_needed( 5125 sqlite3*, 5126 void*, 5127 void(*)(void*,sqlite3*,int eTextRep,const char*) 5128); 5129int sqlite3_collation_needed16( 5130 sqlite3*, 5131 void*, 5132 void(*)(void*,sqlite3*,int eTextRep,const void*) 5133); 5134 5135#ifdef SQLITE_HAS_CODEC 5136/* 5137** Specify the key for an encrypted database. This routine should be 5138** called right after sqlite3_open(). 5139** 5140** The code to implement this API is not available in the public release 5141** of SQLite. 5142*/ 5143int sqlite3_key( 5144 sqlite3 *db, /* Database to be rekeyed */ 5145 const void *pKey, int nKey /* The key */ 5146); 5147int sqlite3_key_v2( 5148 sqlite3 *db, /* Database to be rekeyed */ 5149 const char *zDbName, /* Name of the database */ 5150 const void *pKey, int nKey /* The key */ 5151); 5152 5153/* 5154** Change the key on an open database. If the current database is not 5155** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 5156** database is decrypted. 5157** 5158** The code to implement this API is not available in the public release 5159** of SQLite. 5160*/ 5161int sqlite3_rekey( 5162 sqlite3 *db, /* Database to be rekeyed */ 5163 const void *pKey, int nKey /* The new key */ 5164); 5165int sqlite3_rekey_v2( 5166 sqlite3 *db, /* Database to be rekeyed */ 5167 const char *zDbName, /* Name of the database */ 5168 const void *pKey, int nKey /* The new key */ 5169); 5170 5171/* 5172** Specify the activation key for a SEE database. Unless 5173** activated, none of the SEE routines will work. 5174*/ 5175void sqlite3_activate_see( 5176 const char *zPassPhrase /* Activation phrase */ 5177); 5178#endif 5179 5180#ifdef SQLITE_ENABLE_CEROD 5181/* 5182** Specify the activation key for a CEROD database. Unless 5183** activated, none of the CEROD routines will work. 5184*/ 5185void sqlite3_activate_cerod( 5186 const char *zPassPhrase /* Activation phrase */ 5187); 5188#endif 5189 5190/* 5191** CAPI3REF: Suspend Execution For A Short Time 5192** 5193** The sqlite3_sleep() function causes the current thread to suspend execution 5194** for at least a number of milliseconds specified in its parameter. 5195** 5196** If the operating system does not support sleep requests with 5197** millisecond time resolution, then the time will be rounded up to 5198** the nearest second. The number of milliseconds of sleep actually 5199** requested from the operating system is returned. 5200** 5201** ^SQLite implements this interface by calling the xSleep() 5202** method of the default [sqlite3_vfs] object. If the xSleep() method 5203** of the default VFS is not implemented correctly, or not implemented at 5204** all, then the behavior of sqlite3_sleep() may deviate from the description 5205** in the previous paragraphs. 5206*/ 5207int sqlite3_sleep(int); 5208 5209/* 5210** CAPI3REF: Name Of The Folder Holding Temporary Files 5211** 5212** ^(If this global variable is made to point to a string which is 5213** the name of a folder (a.k.a. directory), then all temporary files 5214** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5215** will be placed in that directory.)^ ^If this variable 5216** is a NULL pointer, then SQLite performs a search for an appropriate 5217** temporary file directory. 5218** 5219** Applications are strongly discouraged from using this global variable. 5220** It is required to set a temporary folder on Windows Runtime (WinRT). 5221** But for all other platforms, it is highly recommended that applications 5222** neither read nor write this variable. This global variable is a relic 5223** that exists for backwards compatibility of legacy applications and should 5224** be avoided in new projects. 5225** 5226** It is not safe to read or modify this variable in more than one 5227** thread at a time. It is not safe to read or modify this variable 5228** if a [database connection] is being used at the same time in a separate 5229** thread. 5230** It is intended that this variable be set once 5231** as part of process initialization and before any SQLite interface 5232** routines have been called and that this variable remain unchanged 5233** thereafter. 5234** 5235** ^The [temp_store_directory pragma] may modify this variable and cause 5236** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5237** the [temp_store_directory pragma] always assumes that any string 5238** that this variable points to is held in memory obtained from 5239** [sqlite3_malloc] and the pragma may attempt to free that memory 5240** using [sqlite3_free]. 5241** Hence, if this variable is modified directly, either it should be 5242** made NULL or made to point to memory obtained from [sqlite3_malloc] 5243** or else the use of the [temp_store_directory pragma] should be avoided. 5244** Except when requested by the [temp_store_directory pragma], SQLite 5245** does not free the memory that sqlite3_temp_directory points to. If 5246** the application wants that memory to be freed, it must do 5247** so itself, taking care to only do so after all [database connection] 5248** objects have been destroyed. 5249** 5250** <b>Note to Windows Runtime users:</b> The temporary directory must be set 5251** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 5252** features that require the use of temporary files may fail. Here is an 5253** example of how to do this using C++ with the Windows Runtime: 5254** 5255** <blockquote><pre> 5256** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 5257** TemporaryFolder->Path->Data(); 5258** char zPathBuf[MAX_PATH + 1]; 5259** memset(zPathBuf, 0, sizeof(zPathBuf)); 5260** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 5261** NULL, NULL); 5262** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 5263** </pre></blockquote> 5264*/ 5265SQLITE_EXTERN char *sqlite3_temp_directory; 5266 5267/* 5268** CAPI3REF: Name Of The Folder Holding Database Files 5269** 5270** ^(If this global variable is made to point to a string which is 5271** the name of a folder (a.k.a. directory), then all database files 5272** specified with a relative pathname and created or accessed by 5273** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 5274** to be relative to that directory.)^ ^If this variable is a NULL 5275** pointer, then SQLite assumes that all database files specified 5276** with a relative pathname are relative to the current directory 5277** for the process. Only the windows VFS makes use of this global 5278** variable; it is ignored by the unix VFS. 5279** 5280** Changing the value of this variable while a database connection is 5281** open can result in a corrupt database. 5282** 5283** It is not safe to read or modify this variable in more than one 5284** thread at a time. It is not safe to read or modify this variable 5285** if a [database connection] is being used at the same time in a separate 5286** thread. 5287** It is intended that this variable be set once 5288** as part of process initialization and before any SQLite interface 5289** routines have been called and that this variable remain unchanged 5290** thereafter. 5291** 5292** ^The [data_store_directory pragma] may modify this variable and cause 5293** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5294** the [data_store_directory pragma] always assumes that any string 5295** that this variable points to is held in memory obtained from 5296** [sqlite3_malloc] and the pragma may attempt to free that memory 5297** using [sqlite3_free]. 5298** Hence, if this variable is modified directly, either it should be 5299** made NULL or made to point to memory obtained from [sqlite3_malloc] 5300** or else the use of the [data_store_directory pragma] should be avoided. 5301*/ 5302SQLITE_EXTERN char *sqlite3_data_directory; 5303 5304/* 5305** CAPI3REF: Test For Auto-Commit Mode 5306** KEYWORDS: {autocommit mode} 5307** METHOD: sqlite3 5308** 5309** ^The sqlite3_get_autocommit() interface returns non-zero or 5310** zero if the given database connection is or is not in autocommit mode, 5311** respectively. ^Autocommit mode is on by default. 5312** ^Autocommit mode is disabled by a [BEGIN] statement. 5313** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5314** 5315** If certain kinds of errors occur on a statement within a multi-statement 5316** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5317** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5318** transaction might be rolled back automatically. The only way to 5319** find out whether SQLite automatically rolled back the transaction after 5320** an error is to use this function. 5321** 5322** If another thread changes the autocommit status of the database 5323** connection while this routine is running, then the return value 5324** is undefined. 5325*/ 5326int sqlite3_get_autocommit(sqlite3*); 5327 5328/* 5329** CAPI3REF: Find The Database Handle Of A Prepared Statement 5330** METHOD: sqlite3_stmt 5331** 5332** ^The sqlite3_db_handle interface returns the [database connection] handle 5333** to which a [prepared statement] belongs. ^The [database connection] 5334** returned by sqlite3_db_handle is the same [database connection] 5335** that was the first argument 5336** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5337** create the statement in the first place. 5338*/ 5339sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5340 5341/* 5342** CAPI3REF: Return The Filename For A Database Connection 5343** METHOD: sqlite3 5344** 5345** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5346** associated with database N of connection D. ^The main database file 5347** has the name "main". If there is no attached database N on the database 5348** connection D, or if database N is a temporary or in-memory database, then 5349** a NULL pointer is returned. 5350** 5351** ^The filename returned by this function is the output of the 5352** xFullPathname method of the [VFS]. ^In other words, the filename 5353** will be an absolute pathname, even if the filename used 5354** to open the database originally was a URI or relative pathname. 5355*/ 5356const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5357 5358/* 5359** CAPI3REF: Determine if a database is read-only 5360** METHOD: sqlite3 5361** 5362** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5363** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5364** the name of a database on connection D. 5365*/ 5366int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5367 5368/* 5369** CAPI3REF: Find the next prepared statement 5370** METHOD: sqlite3 5371** 5372** ^This interface returns a pointer to the next [prepared statement] after 5373** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5374** then this interface returns a pointer to the first prepared statement 5375** associated with the database connection pDb. ^If no prepared statement 5376** satisfies the conditions of this routine, it returns NULL. 5377** 5378** The [database connection] pointer D in a call to 5379** [sqlite3_next_stmt(D,S)] must refer to an open database 5380** connection and in particular must not be a NULL pointer. 5381*/ 5382sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5383 5384/* 5385** CAPI3REF: Commit And Rollback Notification Callbacks 5386** METHOD: sqlite3 5387** 5388** ^The sqlite3_commit_hook() interface registers a callback 5389** function to be invoked whenever a transaction is [COMMIT | committed]. 5390** ^Any callback set by a previous call to sqlite3_commit_hook() 5391** for the same database connection is overridden. 5392** ^The sqlite3_rollback_hook() interface registers a callback 5393** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5394** ^Any callback set by a previous call to sqlite3_rollback_hook() 5395** for the same database connection is overridden. 5396** ^The pArg argument is passed through to the callback. 5397** ^If the callback on a commit hook function returns non-zero, 5398** then the commit is converted into a rollback. 5399** 5400** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5401** return the P argument from the previous call of the same function 5402** on the same [database connection] D, or NULL for 5403** the first call for each function on D. 5404** 5405** The commit and rollback hook callbacks are not reentrant. 5406** The callback implementation must not do anything that will modify 5407** the database connection that invoked the callback. Any actions 5408** to modify the database connection must be deferred until after the 5409** completion of the [sqlite3_step()] call that triggered the commit 5410** or rollback hook in the first place. 5411** Note that running any other SQL statements, including SELECT statements, 5412** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5413** the database connections for the meaning of "modify" in this paragraph. 5414** 5415** ^Registering a NULL function disables the callback. 5416** 5417** ^When the commit hook callback routine returns zero, the [COMMIT] 5418** operation is allowed to continue normally. ^If the commit hook 5419** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5420** ^The rollback hook is invoked on a rollback that results from a commit 5421** hook returning non-zero, just as it would be with any other rollback. 5422** 5423** ^For the purposes of this API, a transaction is said to have been 5424** rolled back if an explicit "ROLLBACK" statement is executed, or 5425** an error or constraint causes an implicit rollback to occur. 5426** ^The rollback callback is not invoked if a transaction is 5427** automatically rolled back because the database connection is closed. 5428** 5429** See also the [sqlite3_update_hook()] interface. 5430*/ 5431void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5432void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5433 5434/* 5435** CAPI3REF: Data Change Notification Callbacks 5436** METHOD: sqlite3 5437** 5438** ^The sqlite3_update_hook() interface registers a callback function 5439** with the [database connection] identified by the first argument 5440** to be invoked whenever a row is updated, inserted or deleted in 5441** a [rowid table]. 5442** ^Any callback set by a previous call to this function 5443** for the same database connection is overridden. 5444** 5445** ^The second argument is a pointer to the function to invoke when a 5446** row is updated, inserted or deleted in a rowid table. 5447** ^The first argument to the callback is a copy of the third argument 5448** to sqlite3_update_hook(). 5449** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5450** or [SQLITE_UPDATE], depending on the operation that caused the callback 5451** to be invoked. 5452** ^The third and fourth arguments to the callback contain pointers to the 5453** database and table name containing the affected row. 5454** ^The final callback parameter is the [rowid] of the row. 5455** ^In the case of an update, this is the [rowid] after the update takes place. 5456** 5457** ^(The update hook is not invoked when internal system tables are 5458** modified (i.e. sqlite_master and sqlite_sequence).)^ 5459** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5460** 5461** ^In the current implementation, the update hook 5462** is not invoked when conflicting rows are deleted because of an 5463** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5464** invoked when rows are deleted using the [truncate optimization]. 5465** The exceptions defined in this paragraph might change in a future 5466** release of SQLite. 5467** 5468** The update hook implementation must not do anything that will modify 5469** the database connection that invoked the update hook. Any actions 5470** to modify the database connection must be deferred until after the 5471** completion of the [sqlite3_step()] call that triggered the update hook. 5472** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5473** database connections for the meaning of "modify" in this paragraph. 5474** 5475** ^The sqlite3_update_hook(D,C,P) function 5476** returns the P argument from the previous call 5477** on the same [database connection] D, or NULL for 5478** the first call on D. 5479** 5480** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 5481** and [sqlite3_preupdate_hook()] interfaces. 5482*/ 5483void *sqlite3_update_hook( 5484 sqlite3*, 5485 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5486 void* 5487); 5488 5489/* 5490** CAPI3REF: Enable Or Disable Shared Pager Cache 5491** 5492** ^(This routine enables or disables the sharing of the database cache 5493** and schema data structures between [database connection | connections] 5494** to the same database. Sharing is enabled if the argument is true 5495** and disabled if the argument is false.)^ 5496** 5497** ^Cache sharing is enabled and disabled for an entire process. 5498** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 5499** In prior versions of SQLite, 5500** sharing was enabled or disabled for each thread separately. 5501** 5502** ^(The cache sharing mode set by this interface effects all subsequent 5503** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5504** Existing database connections continue use the sharing mode 5505** that was in effect at the time they were opened.)^ 5506** 5507** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5508** successfully. An [error code] is returned otherwise.)^ 5509** 5510** ^Shared cache is disabled by default. But this might change in 5511** future releases of SQLite. Applications that care about shared 5512** cache setting should set it explicitly. 5513** 5514** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5515** and will always return SQLITE_MISUSE. On those systems, 5516** shared cache mode should be enabled per-database connection via 5517** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5518** 5519** This interface is threadsafe on processors where writing a 5520** 32-bit integer is atomic. 5521** 5522** See Also: [SQLite Shared-Cache Mode] 5523*/ 5524int sqlite3_enable_shared_cache(int); 5525 5526/* 5527** CAPI3REF: Attempt To Free Heap Memory 5528** 5529** ^The sqlite3_release_memory() interface attempts to free N bytes 5530** of heap memory by deallocating non-essential memory allocations 5531** held by the database library. Memory used to cache database 5532** pages to improve performance is an example of non-essential memory. 5533** ^sqlite3_release_memory() returns the number of bytes actually freed, 5534** which might be more or less than the amount requested. 5535** ^The sqlite3_release_memory() routine is a no-op returning zero 5536** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5537** 5538** See also: [sqlite3_db_release_memory()] 5539*/ 5540int sqlite3_release_memory(int); 5541 5542/* 5543** CAPI3REF: Free Memory Used By A Database Connection 5544** METHOD: sqlite3 5545** 5546** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5547** memory as possible from database connection D. Unlike the 5548** [sqlite3_release_memory()] interface, this interface is in effect even 5549** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5550** omitted. 5551** 5552** See also: [sqlite3_release_memory()] 5553*/ 5554int sqlite3_db_release_memory(sqlite3*); 5555 5556/* 5557** CAPI3REF: Impose A Limit On Heap Size 5558** 5559** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5560** soft limit on the amount of heap memory that may be allocated by SQLite. 5561** ^SQLite strives to keep heap memory utilization below the soft heap 5562** limit by reducing the number of pages held in the page cache 5563** as heap memory usages approaches the limit. 5564** ^The soft heap limit is "soft" because even though SQLite strives to stay 5565** below the limit, it will exceed the limit rather than generate 5566** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5567** is advisory only. 5568** 5569** ^The return value from sqlite3_soft_heap_limit64() is the size of 5570** the soft heap limit prior to the call, or negative in the case of an 5571** error. ^If the argument N is negative 5572** then no change is made to the soft heap limit. Hence, the current 5573** size of the soft heap limit can be determined by invoking 5574** sqlite3_soft_heap_limit64() with a negative argument. 5575** 5576** ^If the argument N is zero then the soft heap limit is disabled. 5577** 5578** ^(The soft heap limit is not enforced in the current implementation 5579** if one or more of following conditions are true: 5580** 5581** <ul> 5582** <li> The soft heap limit is set to zero. 5583** <li> Memory accounting is disabled using a combination of the 5584** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5585** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5586** <li> An alternative page cache implementation is specified using 5587** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5588** <li> The page cache allocates from its own memory pool supplied 5589** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5590** from the heap. 5591** </ul>)^ 5592** 5593** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]), 5594** the soft heap limit is enforced 5595** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5596** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5597** the soft heap limit is enforced on every memory allocation. Without 5598** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5599** when memory is allocated by the page cache. Testing suggests that because 5600** the page cache is the predominate memory user in SQLite, most 5601** applications will achieve adequate soft heap limit enforcement without 5602** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5603** 5604** The circumstances under which SQLite will enforce the soft heap limit may 5605** changes in future releases of SQLite. 5606*/ 5607sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5608 5609/* 5610** CAPI3REF: Deprecated Soft Heap Limit Interface 5611** DEPRECATED 5612** 5613** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5614** interface. This routine is provided for historical compatibility 5615** only. All new applications should use the 5616** [sqlite3_soft_heap_limit64()] interface rather than this one. 5617*/ 5618SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5619 5620 5621/* 5622** CAPI3REF: Extract Metadata About A Column Of A Table 5623** METHOD: sqlite3 5624** 5625** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5626** information about column C of table T in database D 5627** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5628** interface returns SQLITE_OK and fills in the non-NULL pointers in 5629** the final five arguments with appropriate values if the specified 5630** column exists. ^The sqlite3_table_column_metadata() interface returns 5631** SQLITE_ERROR and if the specified column does not exist. 5632** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5633** NULL pointer, then this routine simply checks for the existence of the 5634** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5635** does not. If the table name parameter T in a call to 5636** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 5637** undefined behavior. 5638** 5639** ^The column is identified by the second, third and fourth parameters to 5640** this function. ^(The second parameter is either the name of the database 5641** (i.e. "main", "temp", or an attached database) containing the specified 5642** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5643** for the table using the same algorithm used by the database engine to 5644** resolve unqualified table references. 5645** 5646** ^The third and fourth parameters to this function are the table and column 5647** name of the desired column, respectively. 5648** 5649** ^Metadata is returned by writing to the memory locations passed as the 5th 5650** and subsequent parameters to this function. ^Any of these arguments may be 5651** NULL, in which case the corresponding element of metadata is omitted. 5652** 5653** ^(<blockquote> 5654** <table border="1"> 5655** <tr><th> Parameter <th> Output<br>Type <th> Description 5656** 5657** <tr><td> 5th <td> const char* <td> Data type 5658** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5659** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5660** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5661** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5662** </table> 5663** </blockquote>)^ 5664** 5665** ^The memory pointed to by the character pointers returned for the 5666** declaration type and collation sequence is valid until the next 5667** call to any SQLite API function. 5668** 5669** ^If the specified table is actually a view, an [error code] is returned. 5670** 5671** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5672** is not a [WITHOUT ROWID] table and an 5673** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5674** parameters are set for the explicitly declared column. ^(If there is no 5675** [INTEGER PRIMARY KEY] column, then the outputs 5676** for the [rowid] are set as follows: 5677** 5678** <pre> 5679** data type: "INTEGER" 5680** collation sequence: "BINARY" 5681** not null: 0 5682** primary key: 1 5683** auto increment: 0 5684** </pre>)^ 5685** 5686** ^This function causes all database schemas to be read from disk and 5687** parsed, if that has not already been done, and returns an error if 5688** any errors are encountered while loading the schema. 5689*/ 5690int sqlite3_table_column_metadata( 5691 sqlite3 *db, /* Connection handle */ 5692 const char *zDbName, /* Database name or NULL */ 5693 const char *zTableName, /* Table name */ 5694 const char *zColumnName, /* Column name */ 5695 char const **pzDataType, /* OUTPUT: Declared data type */ 5696 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5697 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5698 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5699 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5700); 5701 5702/* 5703** CAPI3REF: Load An Extension 5704** METHOD: sqlite3 5705** 5706** ^This interface loads an SQLite extension library from the named file. 5707** 5708** ^The sqlite3_load_extension() interface attempts to load an 5709** [SQLite extension] library contained in the file zFile. If 5710** the file cannot be loaded directly, attempts are made to load 5711** with various operating-system specific extensions added. 5712** So for example, if "samplelib" cannot be loaded, then names like 5713** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5714** be tried also. 5715** 5716** ^The entry point is zProc. 5717** ^(zProc may be 0, in which case SQLite will try to come up with an 5718** entry point name on its own. It first tries "sqlite3_extension_init". 5719** If that does not work, it constructs a name "sqlite3_X_init" where the 5720** X is consists of the lower-case equivalent of all ASCII alphabetic 5721** characters in the filename from the last "/" to the first following 5722** "." and omitting any initial "lib".)^ 5723** ^The sqlite3_load_extension() interface returns 5724** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5725** ^If an error occurs and pzErrMsg is not 0, then the 5726** [sqlite3_load_extension()] interface shall attempt to 5727** fill *pzErrMsg with error message text stored in memory 5728** obtained from [sqlite3_malloc()]. The calling function 5729** should free this memory by calling [sqlite3_free()]. 5730** 5731** ^Extension loading must be enabled using 5732** [sqlite3_enable_load_extension()] or 5733** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 5734** prior to calling this API, 5735** otherwise an error will be returned. 5736** 5737** <b>Security warning:</b> It is recommended that the 5738** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 5739** interface. The use of the [sqlite3_enable_load_extension()] interface 5740** should be avoided. This will keep the SQL function [load_extension()] 5741** disabled and prevent SQL injections from giving attackers 5742** access to extension loading capabilities. 5743** 5744** See also the [load_extension() SQL function]. 5745*/ 5746int sqlite3_load_extension( 5747 sqlite3 *db, /* Load the extension into this database connection */ 5748 const char *zFile, /* Name of the shared library containing extension */ 5749 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5750 char **pzErrMsg /* Put error message here if not 0 */ 5751); 5752 5753/* 5754** CAPI3REF: Enable Or Disable Extension Loading 5755** METHOD: sqlite3 5756** 5757** ^So as not to open security holes in older applications that are 5758** unprepared to deal with [extension loading], and as a means of disabling 5759** [extension loading] while evaluating user-entered SQL, the following API 5760** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5761** 5762** ^Extension loading is off by default. 5763** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5764** to turn extension loading on and call it with onoff==0 to turn 5765** it back off again. 5766** 5767** ^This interface enables or disables both the C-API 5768** [sqlite3_load_extension()] and the SQL function [load_extension()]. 5769** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 5770** to enable or disable only the C-API.)^ 5771** 5772** <b>Security warning:</b> It is recommended that extension loading 5773** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 5774** rather than this interface, so the [load_extension()] SQL function 5775** remains disabled. This will prevent SQL injections from giving attackers 5776** access to extension loading capabilities. 5777*/ 5778int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5779 5780/* 5781** CAPI3REF: Automatically Load Statically Linked Extensions 5782** 5783** ^This interface causes the xEntryPoint() function to be invoked for 5784** each new [database connection] that is created. The idea here is that 5785** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5786** that is to be automatically loaded into all new database connections. 5787** 5788** ^(Even though the function prototype shows that xEntryPoint() takes 5789** no arguments and returns void, SQLite invokes xEntryPoint() with three 5790** arguments and expects an integer result as if the signature of the 5791** entry point where as follows: 5792** 5793** <blockquote><pre> 5794** int xEntryPoint( 5795** sqlite3 *db, 5796** const char **pzErrMsg, 5797** const struct sqlite3_api_routines *pThunk 5798** ); 5799** </pre></blockquote>)^ 5800** 5801** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5802** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5803** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5804** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5805** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5806** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5807** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 5808** 5809** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 5810** on the list of automatic extensions is a harmless no-op. ^No entry point 5811** will be called more than once for each database connection that is opened. 5812** 5813** See also: [sqlite3_reset_auto_extension()] 5814** and [sqlite3_cancel_auto_extension()] 5815*/ 5816int sqlite3_auto_extension(void(*xEntryPoint)(void)); 5817 5818/* 5819** CAPI3REF: Cancel Automatic Extension Loading 5820** 5821** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 5822** initialization routine X that was registered using a prior call to 5823** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 5824** routine returns 1 if initialization routine X was successfully 5825** unregistered and it returns 0 if X was not on the list of initialization 5826** routines. 5827*/ 5828int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 5829 5830/* 5831** CAPI3REF: Reset Automatic Extension Loading 5832** 5833** ^This interface disables all automatic extensions previously 5834** registered using [sqlite3_auto_extension()]. 5835*/ 5836void sqlite3_reset_auto_extension(void); 5837 5838/* 5839** The interface to the virtual-table mechanism is currently considered 5840** to be experimental. The interface might change in incompatible ways. 5841** If this is a problem for you, do not use the interface at this time. 5842** 5843** When the virtual-table mechanism stabilizes, we will declare the 5844** interface fixed, support it indefinitely, and remove this comment. 5845*/ 5846 5847/* 5848** Structures used by the virtual table interface 5849*/ 5850typedef struct sqlite3_vtab sqlite3_vtab; 5851typedef struct sqlite3_index_info sqlite3_index_info; 5852typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 5853typedef struct sqlite3_module sqlite3_module; 5854 5855/* 5856** CAPI3REF: Virtual Table Object 5857** KEYWORDS: sqlite3_module {virtual table module} 5858** 5859** This structure, sometimes called a "virtual table module", 5860** defines the implementation of a [virtual tables]. 5861** This structure consists mostly of methods for the module. 5862** 5863** ^A virtual table module is created by filling in a persistent 5864** instance of this structure and passing a pointer to that instance 5865** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 5866** ^The registration remains valid until it is replaced by a different 5867** module or until the [database connection] closes. The content 5868** of this structure must not change while it is registered with 5869** any database connection. 5870*/ 5871struct sqlite3_module { 5872 int iVersion; 5873 int (*xCreate)(sqlite3*, void *pAux, 5874 int argc, const char *const*argv, 5875 sqlite3_vtab **ppVTab, char**); 5876 int (*xConnect)(sqlite3*, void *pAux, 5877 int argc, const char *const*argv, 5878 sqlite3_vtab **ppVTab, char**); 5879 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 5880 int (*xDisconnect)(sqlite3_vtab *pVTab); 5881 int (*xDestroy)(sqlite3_vtab *pVTab); 5882 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 5883 int (*xClose)(sqlite3_vtab_cursor*); 5884 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 5885 int argc, sqlite3_value **argv); 5886 int (*xNext)(sqlite3_vtab_cursor*); 5887 int (*xEof)(sqlite3_vtab_cursor*); 5888 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 5889 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 5890 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 5891 int (*xBegin)(sqlite3_vtab *pVTab); 5892 int (*xSync)(sqlite3_vtab *pVTab); 5893 int (*xCommit)(sqlite3_vtab *pVTab); 5894 int (*xRollback)(sqlite3_vtab *pVTab); 5895 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 5896 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 5897 void **ppArg); 5898 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 5899 /* The methods above are in version 1 of the sqlite_module object. Those 5900 ** below are for version 2 and greater. */ 5901 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 5902 int (*xRelease)(sqlite3_vtab *pVTab, int); 5903 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 5904}; 5905 5906/* 5907** CAPI3REF: Virtual Table Indexing Information 5908** KEYWORDS: sqlite3_index_info 5909** 5910** The sqlite3_index_info structure and its substructures is used as part 5911** of the [virtual table] interface to 5912** pass information into and receive the reply from the [xBestIndex] 5913** method of a [virtual table module]. The fields under **Inputs** are the 5914** inputs to xBestIndex and are read-only. xBestIndex inserts its 5915** results into the **Outputs** fields. 5916** 5917** ^(The aConstraint[] array records WHERE clause constraints of the form: 5918** 5919** <blockquote>column OP expr</blockquote> 5920** 5921** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 5922** stored in aConstraint[].op using one of the 5923** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 5924** ^(The index of the column is stored in 5925** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5926** expr on the right-hand side can be evaluated (and thus the constraint 5927** is usable) and false if it cannot.)^ 5928** 5929** ^The optimizer automatically inverts terms of the form "expr OP column" 5930** and makes other simplifications to the WHERE clause in an attempt to 5931** get as many WHERE clause terms into the form shown above as possible. 5932** ^The aConstraint[] array only reports WHERE clause terms that are 5933** relevant to the particular virtual table being queried. 5934** 5935** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5936** ^Each term of aOrderBy records a column of the ORDER BY clause. 5937** 5938** The colUsed field indicates which columns of the virtual table may be 5939** required by the current scan. Virtual table columns are numbered from 5940** zero in the order in which they appear within the CREATE TABLE statement 5941** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 5942** the corresponding bit is set within the colUsed mask if the column may be 5943** required by SQLite. If the table has at least 64 columns and any column 5944** to the right of the first 63 is required, then bit 63 of colUsed is also 5945** set. In other words, column iCol may be required if the expression 5946** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 5947** non-zero. 5948** 5949** The [xBestIndex] method must fill aConstraintUsage[] with information 5950** about what parameters to pass to xFilter. ^If argvIndex>0 then 5951** the right-hand side of the corresponding aConstraint[] is evaluated 5952** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5953** is true, then the constraint is assumed to be fully handled by the 5954** virtual table and is not checked again by SQLite.)^ 5955** 5956** ^The idxNum and idxPtr values are recorded and passed into the 5957** [xFilter] method. 5958** ^[sqlite3_free()] is used to free idxPtr if and only if 5959** needToFreeIdxPtr is true. 5960** 5961** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5962** the correct order to satisfy the ORDER BY clause so that no separate 5963** sorting step is required. 5964** 5965** ^The estimatedCost value is an estimate of the cost of a particular 5966** strategy. A cost of N indicates that the cost of the strategy is similar 5967** to a linear scan of an SQLite table with N rows. A cost of log(N) 5968** indicates that the expense of the operation is similar to that of a 5969** binary search on a unique indexed field of an SQLite table with N rows. 5970** 5971** ^The estimatedRows value is an estimate of the number of rows that 5972** will be returned by the strategy. 5973** 5974** The xBestIndex method may optionally populate the idxFlags field with a 5975** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 5976** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 5977** assumes that the strategy may visit at most one row. 5978** 5979** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 5980** SQLite also assumes that if a call to the xUpdate() method is made as 5981** part of the same statement to delete or update a virtual table row and the 5982** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 5983** any database changes. In other words, if the xUpdate() returns 5984** SQLITE_CONSTRAINT, the database contents must be exactly as they were 5985** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 5986** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 5987** the xUpdate method are automatically rolled back by SQLite. 5988** 5989** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 5990** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 5991** If a virtual table extension is 5992** used with an SQLite version earlier than 3.8.2, the results of attempting 5993** to read or write the estimatedRows field are undefined (but are likely 5994** to included crashing the application). The estimatedRows field should 5995** therefore only be used if [sqlite3_libversion_number()] returns a 5996** value greater than or equal to 3008002. Similarly, the idxFlags field 5997** was added for [version 3.9.0] ([dateof:3.9.0]). 5998** It may therefore only be used if 5999** sqlite3_libversion_number() returns a value greater than or equal to 6000** 3009000. 6001*/ 6002struct sqlite3_index_info { 6003 /* Inputs */ 6004 int nConstraint; /* Number of entries in aConstraint */ 6005 struct sqlite3_index_constraint { 6006 int iColumn; /* Column constrained. -1 for ROWID */ 6007 unsigned char op; /* Constraint operator */ 6008 unsigned char usable; /* True if this constraint is usable */ 6009 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6010 } *aConstraint; /* Table of WHERE clause constraints */ 6011 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6012 struct sqlite3_index_orderby { 6013 int iColumn; /* Column number */ 6014 unsigned char desc; /* True for DESC. False for ASC. */ 6015 } *aOrderBy; /* The ORDER BY clause */ 6016 /* Outputs */ 6017 struct sqlite3_index_constraint_usage { 6018 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6019 unsigned char omit; /* Do not code a test for this constraint */ 6020 } *aConstraintUsage; 6021 int idxNum; /* Number used to identify the index */ 6022 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6023 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6024 int orderByConsumed; /* True if output is already ordered */ 6025 double estimatedCost; /* Estimated cost of using this index */ 6026 /* Fields below are only available in SQLite 3.8.2 and later */ 6027 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6028 /* Fields below are only available in SQLite 3.9.0 and later */ 6029 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6030 /* Fields below are only available in SQLite 3.10.0 and later */ 6031 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6032}; 6033 6034/* 6035** CAPI3REF: Virtual Table Scan Flags 6036*/ 6037#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6038 6039/* 6040** CAPI3REF: Virtual Table Constraint Operator Codes 6041** 6042** These macros defined the allowed values for the 6043** [sqlite3_index_info].aConstraint[].op field. Each value represents 6044** an operator that is part of a constraint term in the wHERE clause of 6045** a query that uses a [virtual table]. 6046*/ 6047#define SQLITE_INDEX_CONSTRAINT_EQ 2 6048#define SQLITE_INDEX_CONSTRAINT_GT 4 6049#define SQLITE_INDEX_CONSTRAINT_LE 8 6050#define SQLITE_INDEX_CONSTRAINT_LT 16 6051#define SQLITE_INDEX_CONSTRAINT_GE 32 6052#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6053#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6054#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6055#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6056 6057/* 6058** CAPI3REF: Register A Virtual Table Implementation 6059** METHOD: sqlite3 6060** 6061** ^These routines are used to register a new [virtual table module] name. 6062** ^Module names must be registered before 6063** creating a new [virtual table] using the module and before using a 6064** preexisting [virtual table] for the module. 6065** 6066** ^The module name is registered on the [database connection] specified 6067** by the first parameter. ^The name of the module is given by the 6068** second parameter. ^The third parameter is a pointer to 6069** the implementation of the [virtual table module]. ^The fourth 6070** parameter is an arbitrary client data pointer that is passed through 6071** into the [xCreate] and [xConnect] methods of the virtual table module 6072** when a new virtual table is be being created or reinitialized. 6073** 6074** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6075** is a pointer to a destructor for the pClientData. ^SQLite will 6076** invoke the destructor function (if it is not NULL) when SQLite 6077** no longer needs the pClientData pointer. ^The destructor will also 6078** be invoked if the call to sqlite3_create_module_v2() fails. 6079** ^The sqlite3_create_module() 6080** interface is equivalent to sqlite3_create_module_v2() with a NULL 6081** destructor. 6082*/ 6083int sqlite3_create_module( 6084 sqlite3 *db, /* SQLite connection to register module with */ 6085 const char *zName, /* Name of the module */ 6086 const sqlite3_module *p, /* Methods for the module */ 6087 void *pClientData /* Client data for xCreate/xConnect */ 6088); 6089int sqlite3_create_module_v2( 6090 sqlite3 *db, /* SQLite connection to register module with */ 6091 const char *zName, /* Name of the module */ 6092 const sqlite3_module *p, /* Methods for the module */ 6093 void *pClientData, /* Client data for xCreate/xConnect */ 6094 void(*xDestroy)(void*) /* Module destructor function */ 6095); 6096 6097/* 6098** CAPI3REF: Virtual Table Instance Object 6099** KEYWORDS: sqlite3_vtab 6100** 6101** Every [virtual table module] implementation uses a subclass 6102** of this object to describe a particular instance 6103** of the [virtual table]. Each subclass will 6104** be tailored to the specific needs of the module implementation. 6105** The purpose of this superclass is to define certain fields that are 6106** common to all module implementations. 6107** 6108** ^Virtual tables methods can set an error message by assigning a 6109** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 6110** take care that any prior string is freed by a call to [sqlite3_free()] 6111** prior to assigning a new string to zErrMsg. ^After the error message 6112** is delivered up to the client application, the string will be automatically 6113** freed by sqlite3_free() and the zErrMsg field will be zeroed. 6114*/ 6115struct sqlite3_vtab { 6116 const sqlite3_module *pModule; /* The module for this virtual table */ 6117 int nRef; /* Number of open cursors */ 6118 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 6119 /* Virtual table implementations will typically add additional fields */ 6120}; 6121 6122/* 6123** CAPI3REF: Virtual Table Cursor Object 6124** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 6125** 6126** Every [virtual table module] implementation uses a subclass of the 6127** following structure to describe cursors that point into the 6128** [virtual table] and are used 6129** to loop through the virtual table. Cursors are created using the 6130** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 6131** by the [sqlite3_module.xClose | xClose] method. Cursors are used 6132** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 6133** of the module. Each module implementation will define 6134** the content of a cursor structure to suit its own needs. 6135** 6136** This superclass exists in order to define fields of the cursor that 6137** are common to all implementations. 6138*/ 6139struct sqlite3_vtab_cursor { 6140 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 6141 /* Virtual table implementations will typically add additional fields */ 6142}; 6143 6144/* 6145** CAPI3REF: Declare The Schema Of A Virtual Table 6146** 6147** ^The [xCreate] and [xConnect] methods of a 6148** [virtual table module] call this interface 6149** to declare the format (the names and datatypes of the columns) of 6150** the virtual tables they implement. 6151*/ 6152int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 6153 6154/* 6155** CAPI3REF: Overload A Function For A Virtual Table 6156** METHOD: sqlite3 6157** 6158** ^(Virtual tables can provide alternative implementations of functions 6159** using the [xFindFunction] method of the [virtual table module]. 6160** But global versions of those functions 6161** must exist in order to be overloaded.)^ 6162** 6163** ^(This API makes sure a global version of a function with a particular 6164** name and number of parameters exists. If no such function exists 6165** before this API is called, a new function is created.)^ ^The implementation 6166** of the new function always causes an exception to be thrown. So 6167** the new function is not good for anything by itself. Its only 6168** purpose is to be a placeholder function that can be overloaded 6169** by a [virtual table]. 6170*/ 6171int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 6172 6173/* 6174** The interface to the virtual-table mechanism defined above (back up 6175** to a comment remarkably similar to this one) is currently considered 6176** to be experimental. The interface might change in incompatible ways. 6177** If this is a problem for you, do not use the interface at this time. 6178** 6179** When the virtual-table mechanism stabilizes, we will declare the 6180** interface fixed, support it indefinitely, and remove this comment. 6181*/ 6182 6183/* 6184** CAPI3REF: A Handle To An Open BLOB 6185** KEYWORDS: {BLOB handle} {BLOB handles} 6186** 6187** An instance of this object represents an open BLOB on which 6188** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 6189** ^Objects of this type are created by [sqlite3_blob_open()] 6190** and destroyed by [sqlite3_blob_close()]. 6191** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 6192** can be used to read or write small subsections of the BLOB. 6193** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 6194*/ 6195typedef struct sqlite3_blob sqlite3_blob; 6196 6197/* 6198** CAPI3REF: Open A BLOB For Incremental I/O 6199** METHOD: sqlite3 6200** CONSTRUCTOR: sqlite3_blob 6201** 6202** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 6203** in row iRow, column zColumn, table zTable in database zDb; 6204** in other words, the same BLOB that would be selected by: 6205** 6206** <pre> 6207** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 6208** </pre>)^ 6209** 6210** ^(Parameter zDb is not the filename that contains the database, but 6211** rather the symbolic name of the database. For attached databases, this is 6212** the name that appears after the AS keyword in the [ATTACH] statement. 6213** For the main database file, the database name is "main". For TEMP 6214** tables, the database name is "temp".)^ 6215** 6216** ^If the flags parameter is non-zero, then the BLOB is opened for read 6217** and write access. ^If the flags parameter is zero, the BLOB is opened for 6218** read-only access. 6219** 6220** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 6221** in *ppBlob. Otherwise an [error code] is returned and, unless the error 6222** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 6223** the API is not misused, it is always safe to call [sqlite3_blob_close()] 6224** on *ppBlob after this function it returns. 6225** 6226** This function fails with SQLITE_ERROR if any of the following are true: 6227** <ul> 6228** <li> ^(Database zDb does not exist)^, 6229** <li> ^(Table zTable does not exist within database zDb)^, 6230** <li> ^(Table zTable is a WITHOUT ROWID table)^, 6231** <li> ^(Column zColumn does not exist)^, 6232** <li> ^(Row iRow is not present in the table)^, 6233** <li> ^(The specified column of row iRow contains a value that is not 6234** a TEXT or BLOB value)^, 6235** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 6236** constraint and the blob is being opened for read/write access)^, 6237** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 6238** column zColumn is part of a [child key] definition and the blob is 6239** being opened for read/write access)^. 6240** </ul> 6241** 6242** ^Unless it returns SQLITE_MISUSE, this function sets the 6243** [database connection] error code and message accessible via 6244** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6245** 6246** A BLOB referenced by sqlite3_blob_open() may be read using the 6247** [sqlite3_blob_read()] interface and modified by using 6248** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 6249** different row of the same table using the [sqlite3_blob_reopen()] 6250** interface. However, the column, table, or database of a [BLOB handle] 6251** cannot be changed after the [BLOB handle] is opened. 6252** 6253** ^(If the row that a BLOB handle points to is modified by an 6254** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 6255** then the BLOB handle is marked as "expired". 6256** This is true if any column of the row is changed, even a column 6257** other than the one the BLOB handle is open on.)^ 6258** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 6259** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 6260** ^(Changes written into a BLOB prior to the BLOB expiring are not 6261** rolled back by the expiration of the BLOB. Such changes will eventually 6262** commit if the transaction continues to completion.)^ 6263** 6264** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 6265** the opened blob. ^The size of a blob may not be changed by this 6266** interface. Use the [UPDATE] SQL command to change the size of a 6267** blob. 6268** 6269** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 6270** and the built-in [zeroblob] SQL function may be used to create a 6271** zero-filled blob to read or write using the incremental-blob interface. 6272** 6273** To avoid a resource leak, every open [BLOB handle] should eventually 6274** be released by a call to [sqlite3_blob_close()]. 6275** 6276** See also: [sqlite3_blob_close()], 6277** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 6278** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 6279*/ 6280int sqlite3_blob_open( 6281 sqlite3*, 6282 const char *zDb, 6283 const char *zTable, 6284 const char *zColumn, 6285 sqlite3_int64 iRow, 6286 int flags, 6287 sqlite3_blob **ppBlob 6288); 6289 6290/* 6291** CAPI3REF: Move a BLOB Handle to a New Row 6292** METHOD: sqlite3_blob 6293** 6294** ^This function is used to move an existing [BLOB handle] so that it points 6295** to a different row of the same database table. ^The new row is identified 6296** by the rowid value passed as the second argument. Only the row can be 6297** changed. ^The database, table and column on which the blob handle is open 6298** remain the same. Moving an existing [BLOB handle] to a new row is 6299** faster than closing the existing handle and opening a new one. 6300** 6301** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 6302** it must exist and there must be either a blob or text value stored in 6303** the nominated column.)^ ^If the new row is not present in the table, or if 6304** it does not contain a blob or text value, or if another error occurs, an 6305** SQLite error code is returned and the blob handle is considered aborted. 6306** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 6307** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 6308** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 6309** always returns zero. 6310** 6311** ^This function sets the database handle error code and message. 6312*/ 6313int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 6314 6315/* 6316** CAPI3REF: Close A BLOB Handle 6317** DESTRUCTOR: sqlite3_blob 6318** 6319** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 6320** unconditionally. Even if this routine returns an error code, the 6321** handle is still closed.)^ 6322** 6323** ^If the blob handle being closed was opened for read-write access, and if 6324** the database is in auto-commit mode and there are no other open read-write 6325** blob handles or active write statements, the current transaction is 6326** committed. ^If an error occurs while committing the transaction, an error 6327** code is returned and the transaction rolled back. 6328** 6329** Calling this function with an argument that is not a NULL pointer or an 6330** open blob handle results in undefined behaviour. ^Calling this routine 6331** with a null pointer (such as would be returned by a failed call to 6332** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 6333** is passed a valid open blob handle, the values returned by the 6334** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 6335*/ 6336int sqlite3_blob_close(sqlite3_blob *); 6337 6338/* 6339** CAPI3REF: Return The Size Of An Open BLOB 6340** METHOD: sqlite3_blob 6341** 6342** ^Returns the size in bytes of the BLOB accessible via the 6343** successfully opened [BLOB handle] in its only argument. ^The 6344** incremental blob I/O routines can only read or overwriting existing 6345** blob content; they cannot change the size of a blob. 6346** 6347** This routine only works on a [BLOB handle] which has been created 6348** by a prior successful call to [sqlite3_blob_open()] and which has not 6349** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6350** to this routine results in undefined and probably undesirable behavior. 6351*/ 6352int sqlite3_blob_bytes(sqlite3_blob *); 6353 6354/* 6355** CAPI3REF: Read Data From A BLOB Incrementally 6356** METHOD: sqlite3_blob 6357** 6358** ^(This function is used to read data from an open [BLOB handle] into a 6359** caller-supplied buffer. N bytes of data are copied into buffer Z 6360** from the open BLOB, starting at offset iOffset.)^ 6361** 6362** ^If offset iOffset is less than N bytes from the end of the BLOB, 6363** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6364** less than zero, [SQLITE_ERROR] is returned and no data is read. 6365** ^The size of the blob (and hence the maximum value of N+iOffset) 6366** can be determined using the [sqlite3_blob_bytes()] interface. 6367** 6368** ^An attempt to read from an expired [BLOB handle] fails with an 6369** error code of [SQLITE_ABORT]. 6370** 6371** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6372** Otherwise, an [error code] or an [extended error code] is returned.)^ 6373** 6374** This routine only works on a [BLOB handle] which has been created 6375** by a prior successful call to [sqlite3_blob_open()] and which has not 6376** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6377** to this routine results in undefined and probably undesirable behavior. 6378** 6379** See also: [sqlite3_blob_write()]. 6380*/ 6381int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6382 6383/* 6384** CAPI3REF: Write Data Into A BLOB Incrementally 6385** METHOD: sqlite3_blob 6386** 6387** ^(This function is used to write data into an open [BLOB handle] from a 6388** caller-supplied buffer. N bytes of data are copied from the buffer Z 6389** into the open BLOB, starting at offset iOffset.)^ 6390** 6391** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6392** Otherwise, an [error code] or an [extended error code] is returned.)^ 6393** ^Unless SQLITE_MISUSE is returned, this function sets the 6394** [database connection] error code and message accessible via 6395** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6396** 6397** ^If the [BLOB handle] passed as the first argument was not opened for 6398** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6399** this function returns [SQLITE_READONLY]. 6400** 6401** This function may only modify the contents of the BLOB; it is 6402** not possible to increase the size of a BLOB using this API. 6403** ^If offset iOffset is less than N bytes from the end of the BLOB, 6404** [SQLITE_ERROR] is returned and no data is written. The size of the 6405** BLOB (and hence the maximum value of N+iOffset) can be determined 6406** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6407** than zero [SQLITE_ERROR] is returned and no data is written. 6408** 6409** ^An attempt to write to an expired [BLOB handle] fails with an 6410** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6411** before the [BLOB handle] expired are not rolled back by the 6412** expiration of the handle, though of course those changes might 6413** have been overwritten by the statement that expired the BLOB handle 6414** or by other independent statements. 6415** 6416** This routine only works on a [BLOB handle] which has been created 6417** by a prior successful call to [sqlite3_blob_open()] and which has not 6418** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6419** to this routine results in undefined and probably undesirable behavior. 6420** 6421** See also: [sqlite3_blob_read()]. 6422*/ 6423int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6424 6425/* 6426** CAPI3REF: Virtual File System Objects 6427** 6428** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6429** that SQLite uses to interact 6430** with the underlying operating system. Most SQLite builds come with a 6431** single default VFS that is appropriate for the host computer. 6432** New VFSes can be registered and existing VFSes can be unregistered. 6433** The following interfaces are provided. 6434** 6435** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6436** ^Names are case sensitive. 6437** ^Names are zero-terminated UTF-8 strings. 6438** ^If there is no match, a NULL pointer is returned. 6439** ^If zVfsName is NULL then the default VFS is returned. 6440** 6441** ^New VFSes are registered with sqlite3_vfs_register(). 6442** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6443** ^The same VFS can be registered multiple times without injury. 6444** ^To make an existing VFS into the default VFS, register it again 6445** with the makeDflt flag set. If two different VFSes with the 6446** same name are registered, the behavior is undefined. If a 6447** VFS is registered with a name that is NULL or an empty string, 6448** then the behavior is undefined. 6449** 6450** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6451** ^(If the default VFS is unregistered, another VFS is chosen as 6452** the default. The choice for the new VFS is arbitrary.)^ 6453*/ 6454sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6455int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6456int sqlite3_vfs_unregister(sqlite3_vfs*); 6457 6458/* 6459** CAPI3REF: Mutexes 6460** 6461** The SQLite core uses these routines for thread 6462** synchronization. Though they are intended for internal 6463** use by SQLite, code that links against SQLite is 6464** permitted to use any of these routines. 6465** 6466** The SQLite source code contains multiple implementations 6467** of these mutex routines. An appropriate implementation 6468** is selected automatically at compile-time. The following 6469** implementations are available in the SQLite core: 6470** 6471** <ul> 6472** <li> SQLITE_MUTEX_PTHREADS 6473** <li> SQLITE_MUTEX_W32 6474** <li> SQLITE_MUTEX_NOOP 6475** </ul> 6476** 6477** The SQLITE_MUTEX_NOOP implementation is a set of routines 6478** that does no real locking and is appropriate for use in 6479** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6480** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6481** and Windows. 6482** 6483** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6484** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6485** implementation is included with the library. In this case the 6486** application must supply a custom mutex implementation using the 6487** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6488** before calling sqlite3_initialize() or any other public sqlite3_ 6489** function that calls sqlite3_initialize(). 6490** 6491** ^The sqlite3_mutex_alloc() routine allocates a new 6492** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6493** routine returns NULL if it is unable to allocate the requested 6494** mutex. The argument to sqlite3_mutex_alloc() must one of these 6495** integer constants: 6496** 6497** <ul> 6498** <li> SQLITE_MUTEX_FAST 6499** <li> SQLITE_MUTEX_RECURSIVE 6500** <li> SQLITE_MUTEX_STATIC_MASTER 6501** <li> SQLITE_MUTEX_STATIC_MEM 6502** <li> SQLITE_MUTEX_STATIC_OPEN 6503** <li> SQLITE_MUTEX_STATIC_PRNG 6504** <li> SQLITE_MUTEX_STATIC_LRU 6505** <li> SQLITE_MUTEX_STATIC_PMEM 6506** <li> SQLITE_MUTEX_STATIC_APP1 6507** <li> SQLITE_MUTEX_STATIC_APP2 6508** <li> SQLITE_MUTEX_STATIC_APP3 6509** <li> SQLITE_MUTEX_STATIC_VFS1 6510** <li> SQLITE_MUTEX_STATIC_VFS2 6511** <li> SQLITE_MUTEX_STATIC_VFS3 6512** </ul> 6513** 6514** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6515** cause sqlite3_mutex_alloc() to create 6516** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6517** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6518** The mutex implementation does not need to make a distinction 6519** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6520** not want to. SQLite will only request a recursive mutex in 6521** cases where it really needs one. If a faster non-recursive mutex 6522** implementation is available on the host platform, the mutex subsystem 6523** might return such a mutex in response to SQLITE_MUTEX_FAST. 6524** 6525** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6526** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6527** a pointer to a static preexisting mutex. ^Nine static mutexes are 6528** used by the current version of SQLite. Future versions of SQLite 6529** may add additional static mutexes. Static mutexes are for internal 6530** use by SQLite only. Applications that use SQLite mutexes should 6531** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6532** SQLITE_MUTEX_RECURSIVE. 6533** 6534** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6535** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6536** returns a different mutex on every call. ^For the static 6537** mutex types, the same mutex is returned on every call that has 6538** the same type number. 6539** 6540** ^The sqlite3_mutex_free() routine deallocates a previously 6541** allocated dynamic mutex. Attempting to deallocate a static 6542** mutex results in undefined behavior. 6543** 6544** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6545** to enter a mutex. ^If another thread is already within the mutex, 6546** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6547** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6548** upon successful entry. ^(Mutexes created using 6549** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6550** In such cases, the 6551** mutex must be exited an equal number of times before another thread 6552** can enter.)^ If the same thread tries to enter any mutex other 6553** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6554** 6555** ^(Some systems (for example, Windows 95) do not support the operation 6556** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6557** will always return SQLITE_BUSY. The SQLite core only ever uses 6558** sqlite3_mutex_try() as an optimization so this is acceptable 6559** behavior.)^ 6560** 6561** ^The sqlite3_mutex_leave() routine exits a mutex that was 6562** previously entered by the same thread. The behavior 6563** is undefined if the mutex is not currently entered by the 6564** calling thread or is not currently allocated. 6565** 6566** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6567** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6568** behave as no-ops. 6569** 6570** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6571*/ 6572sqlite3_mutex *sqlite3_mutex_alloc(int); 6573void sqlite3_mutex_free(sqlite3_mutex*); 6574void sqlite3_mutex_enter(sqlite3_mutex*); 6575int sqlite3_mutex_try(sqlite3_mutex*); 6576void sqlite3_mutex_leave(sqlite3_mutex*); 6577 6578/* 6579** CAPI3REF: Mutex Methods Object 6580** 6581** An instance of this structure defines the low-level routines 6582** used to allocate and use mutexes. 6583** 6584** Usually, the default mutex implementations provided by SQLite are 6585** sufficient, however the application has the option of substituting a custom 6586** implementation for specialized deployments or systems for which SQLite 6587** does not provide a suitable implementation. In this case, the application 6588** creates and populates an instance of this structure to pass 6589** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6590** Additionally, an instance of this structure can be used as an 6591** output variable when querying the system for the current mutex 6592** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6593** 6594** ^The xMutexInit method defined by this structure is invoked as 6595** part of system initialization by the sqlite3_initialize() function. 6596** ^The xMutexInit routine is called by SQLite exactly once for each 6597** effective call to [sqlite3_initialize()]. 6598** 6599** ^The xMutexEnd method defined by this structure is invoked as 6600** part of system shutdown by the sqlite3_shutdown() function. The 6601** implementation of this method is expected to release all outstanding 6602** resources obtained by the mutex methods implementation, especially 6603** those obtained by the xMutexInit method. ^The xMutexEnd() 6604** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6605** 6606** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6607** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6608** xMutexNotheld) implement the following interfaces (respectively): 6609** 6610** <ul> 6611** <li> [sqlite3_mutex_alloc()] </li> 6612** <li> [sqlite3_mutex_free()] </li> 6613** <li> [sqlite3_mutex_enter()] </li> 6614** <li> [sqlite3_mutex_try()] </li> 6615** <li> [sqlite3_mutex_leave()] </li> 6616** <li> [sqlite3_mutex_held()] </li> 6617** <li> [sqlite3_mutex_notheld()] </li> 6618** </ul>)^ 6619** 6620** The only difference is that the public sqlite3_XXX functions enumerated 6621** above silently ignore any invocations that pass a NULL pointer instead 6622** of a valid mutex handle. The implementations of the methods defined 6623** by this structure are not required to handle this case, the results 6624** of passing a NULL pointer instead of a valid mutex handle are undefined 6625** (i.e. it is acceptable to provide an implementation that segfaults if 6626** it is passed a NULL pointer). 6627** 6628** The xMutexInit() method must be threadsafe. It must be harmless to 6629** invoke xMutexInit() multiple times within the same process and without 6630** intervening calls to xMutexEnd(). Second and subsequent calls to 6631** xMutexInit() must be no-ops. 6632** 6633** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6634** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6635** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6636** memory allocation for a fast or recursive mutex. 6637** 6638** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6639** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6640** If xMutexInit fails in any way, it is expected to clean up after itself 6641** prior to returning. 6642*/ 6643typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6644struct sqlite3_mutex_methods { 6645 int (*xMutexInit)(void); 6646 int (*xMutexEnd)(void); 6647 sqlite3_mutex *(*xMutexAlloc)(int); 6648 void (*xMutexFree)(sqlite3_mutex *); 6649 void (*xMutexEnter)(sqlite3_mutex *); 6650 int (*xMutexTry)(sqlite3_mutex *); 6651 void (*xMutexLeave)(sqlite3_mutex *); 6652 int (*xMutexHeld)(sqlite3_mutex *); 6653 int (*xMutexNotheld)(sqlite3_mutex *); 6654}; 6655 6656/* 6657** CAPI3REF: Mutex Verification Routines 6658** 6659** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6660** are intended for use inside assert() statements. The SQLite core 6661** never uses these routines except inside an assert() and applications 6662** are advised to follow the lead of the core. The SQLite core only 6663** provides implementations for these routines when it is compiled 6664** with the SQLITE_DEBUG flag. External mutex implementations 6665** are only required to provide these routines if SQLITE_DEBUG is 6666** defined and if NDEBUG is not defined. 6667** 6668** These routines should return true if the mutex in their argument 6669** is held or not held, respectively, by the calling thread. 6670** 6671** The implementation is not required to provide versions of these 6672** routines that actually work. If the implementation does not provide working 6673** versions of these routines, it should at least provide stubs that always 6674** return true so that one does not get spurious assertion failures. 6675** 6676** If the argument to sqlite3_mutex_held() is a NULL pointer then 6677** the routine should return 1. This seems counter-intuitive since 6678** clearly the mutex cannot be held if it does not exist. But 6679** the reason the mutex does not exist is because the build is not 6680** using mutexes. And we do not want the assert() containing the 6681** call to sqlite3_mutex_held() to fail, so a non-zero return is 6682** the appropriate thing to do. The sqlite3_mutex_notheld() 6683** interface should also return 1 when given a NULL pointer. 6684*/ 6685#ifndef NDEBUG 6686int sqlite3_mutex_held(sqlite3_mutex*); 6687int sqlite3_mutex_notheld(sqlite3_mutex*); 6688#endif 6689 6690/* 6691** CAPI3REF: Mutex Types 6692** 6693** The [sqlite3_mutex_alloc()] interface takes a single argument 6694** which is one of these integer constants. 6695** 6696** The set of static mutexes may change from one SQLite release to the 6697** next. Applications that override the built-in mutex logic must be 6698** prepared to accommodate additional static mutexes. 6699*/ 6700#define SQLITE_MUTEX_FAST 0 6701#define SQLITE_MUTEX_RECURSIVE 1 6702#define SQLITE_MUTEX_STATIC_MASTER 2 6703#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6704#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6705#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6706#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 6707#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6708#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6709#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6710#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6711#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6712#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6713#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 6714#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 6715#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 6716 6717/* 6718** CAPI3REF: Retrieve the mutex for a database connection 6719** METHOD: sqlite3 6720** 6721** ^This interface returns a pointer the [sqlite3_mutex] object that 6722** serializes access to the [database connection] given in the argument 6723** when the [threading mode] is Serialized. 6724** ^If the [threading mode] is Single-thread or Multi-thread then this 6725** routine returns a NULL pointer. 6726*/ 6727sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 6728 6729/* 6730** CAPI3REF: Low-Level Control Of Database Files 6731** METHOD: sqlite3 6732** 6733** ^The [sqlite3_file_control()] interface makes a direct call to the 6734** xFileControl method for the [sqlite3_io_methods] object associated 6735** with a particular database identified by the second argument. ^The 6736** name of the database is "main" for the main database or "temp" for the 6737** TEMP database, or the name that appears after the AS keyword for 6738** databases that are added using the [ATTACH] SQL command. 6739** ^A NULL pointer can be used in place of "main" to refer to the 6740** main database file. 6741** ^The third and fourth parameters to this routine 6742** are passed directly through to the second and third parameters of 6743** the xFileControl method. ^The return value of the xFileControl 6744** method becomes the return value of this routine. 6745** 6746** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 6747** a pointer to the underlying [sqlite3_file] object to be written into 6748** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 6749** case is a short-circuit path which does not actually invoke the 6750** underlying sqlite3_io_methods.xFileControl method. 6751** 6752** ^If the second parameter (zDbName) does not match the name of any 6753** open database file, then SQLITE_ERROR is returned. ^This error 6754** code is not remembered and will not be recalled by [sqlite3_errcode()] 6755** or [sqlite3_errmsg()]. The underlying xFileControl method might 6756** also return SQLITE_ERROR. There is no way to distinguish between 6757** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6758** xFileControl method. 6759** 6760** See also: [SQLITE_FCNTL_LOCKSTATE] 6761*/ 6762int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6763 6764/* 6765** CAPI3REF: Testing Interface 6766** 6767** ^The sqlite3_test_control() interface is used to read out internal 6768** state of SQLite and to inject faults into SQLite for testing 6769** purposes. ^The first parameter is an operation code that determines 6770** the number, meaning, and operation of all subsequent parameters. 6771** 6772** This interface is not for use by applications. It exists solely 6773** for verifying the correct operation of the SQLite library. Depending 6774** on how the SQLite library is compiled, this interface might not exist. 6775** 6776** The details of the operation codes, their meanings, the parameters 6777** they take, and what they do are all subject to change without notice. 6778** Unlike most of the SQLite API, this function is not guaranteed to 6779** operate consistently from one release to the next. 6780*/ 6781int sqlite3_test_control(int op, ...); 6782 6783/* 6784** CAPI3REF: Testing Interface Operation Codes 6785** 6786** These constants are the valid operation code parameters used 6787** as the first argument to [sqlite3_test_control()]. 6788** 6789** These parameters and their meanings are subject to change 6790** without notice. These values are for testing purposes only. 6791** Applications should not use any of these parameters or the 6792** [sqlite3_test_control()] interface. 6793*/ 6794#define SQLITE_TESTCTRL_FIRST 5 6795#define SQLITE_TESTCTRL_PRNG_SAVE 5 6796#define SQLITE_TESTCTRL_PRNG_RESTORE 6 6797#define SQLITE_TESTCTRL_PRNG_RESET 7 6798#define SQLITE_TESTCTRL_BITVEC_TEST 8 6799#define SQLITE_TESTCTRL_FAULT_INSTALL 9 6800#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 6801#define SQLITE_TESTCTRL_PENDING_BYTE 11 6802#define SQLITE_TESTCTRL_ASSERT 12 6803#define SQLITE_TESTCTRL_ALWAYS 13 6804#define SQLITE_TESTCTRL_RESERVE 14 6805#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 6806#define SQLITE_TESTCTRL_ISKEYWORD 16 6807#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 6808#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 6809#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 6810#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 6811#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 6812#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 6813#define SQLITE_TESTCTRL_BYTEORDER 22 6814#define SQLITE_TESTCTRL_ISINIT 23 6815#define SQLITE_TESTCTRL_SORTER_MMAP 24 6816#define SQLITE_TESTCTRL_IMPOSTER 25 6817#define SQLITE_TESTCTRL_LAST 25 6818 6819/* 6820** CAPI3REF: SQLite Runtime Status 6821** 6822** ^These interfaces are used to retrieve runtime status information 6823** about the performance of SQLite, and optionally to reset various 6824** highwater marks. ^The first argument is an integer code for 6825** the specific parameter to measure. ^(Recognized integer codes 6826** are of the form [status parameters | SQLITE_STATUS_...].)^ 6827** ^The current value of the parameter is returned into *pCurrent. 6828** ^The highest recorded value is returned in *pHighwater. ^If the 6829** resetFlag is true, then the highest record value is reset after 6830** *pHighwater is written. ^(Some parameters do not record the highest 6831** value. For those parameters 6832** nothing is written into *pHighwater and the resetFlag is ignored.)^ 6833** ^(Other parameters record only the highwater mark and not the current 6834** value. For these latter parameters nothing is written into *pCurrent.)^ 6835** 6836** ^The sqlite3_status() and sqlite3_status64() routines return 6837** SQLITE_OK on success and a non-zero [error code] on failure. 6838** 6839** If either the current value or the highwater mark is too large to 6840** be represented by a 32-bit integer, then the values returned by 6841** sqlite3_status() are undefined. 6842** 6843** See also: [sqlite3_db_status()] 6844*/ 6845int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 6846int sqlite3_status64( 6847 int op, 6848 sqlite3_int64 *pCurrent, 6849 sqlite3_int64 *pHighwater, 6850 int resetFlag 6851); 6852 6853 6854/* 6855** CAPI3REF: Status Parameters 6856** KEYWORDS: {status parameters} 6857** 6858** These integer constants designate various run-time status parameters 6859** that can be returned by [sqlite3_status()]. 6860** 6861** <dl> 6862** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 6863** <dd>This parameter is the current amount of memory checked out 6864** using [sqlite3_malloc()], either directly or indirectly. The 6865** figure includes calls made to [sqlite3_malloc()] by the application 6866** and internal memory usage by the SQLite library. Scratch memory 6867** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 6868** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 6869** this parameter. The amount returned is the sum of the allocation 6870** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 6871** 6872** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 6873** <dd>This parameter records the largest memory allocation request 6874** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 6875** internal equivalents). Only the value returned in the 6876** *pHighwater parameter to [sqlite3_status()] is of interest. 6877** The value written into the *pCurrent parameter is undefined.</dd>)^ 6878** 6879** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 6880** <dd>This parameter records the number of separate memory allocations 6881** currently checked out.</dd>)^ 6882** 6883** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 6884** <dd>This parameter returns the number of pages used out of the 6885** [pagecache memory allocator] that was configured using 6886** [SQLITE_CONFIG_PAGECACHE]. The 6887** value returned is in pages, not in bytes.</dd>)^ 6888** 6889** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 6890** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 6891** <dd>This parameter returns the number of bytes of page cache 6892** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 6893** buffer and where forced to overflow to [sqlite3_malloc()]. The 6894** returned value includes allocations that overflowed because they 6895** where too large (they were larger than the "sz" parameter to 6896** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 6897** no space was left in the page cache.</dd>)^ 6898** 6899** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 6900** <dd>This parameter records the largest memory allocation request 6901** handed to [pagecache memory allocator]. Only the value returned in the 6902** *pHighwater parameter to [sqlite3_status()] is of interest. 6903** The value written into the *pCurrent parameter is undefined.</dd>)^ 6904** 6905** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 6906** <dd>This parameter returns the number of allocations used out of the 6907** [scratch memory allocator] configured using 6908** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 6909** in bytes. Since a single thread may only have one scratch allocation 6910** outstanding at time, this parameter also reports the number of threads 6911** using scratch memory at the same time.</dd>)^ 6912** 6913** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 6914** <dd>This parameter returns the number of bytes of scratch memory 6915** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 6916** buffer and where forced to overflow to [sqlite3_malloc()]. The values 6917** returned include overflows because the requested allocation was too 6918** larger (that is, because the requested allocation was larger than the 6919** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 6920** slots were available. 6921** </dd>)^ 6922** 6923** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 6924** <dd>This parameter records the largest memory allocation request 6925** handed to [scratch memory allocator]. Only the value returned in the 6926** *pHighwater parameter to [sqlite3_status()] is of interest. 6927** The value written into the *pCurrent parameter is undefined.</dd>)^ 6928** 6929** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 6930** <dd>The *pHighwater parameter records the deepest parser stack. 6931** The *pCurrent value is undefined. The *pHighwater value is only 6932** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 6933** </dl> 6934** 6935** New status parameters may be added from time to time. 6936*/ 6937#define SQLITE_STATUS_MEMORY_USED 0 6938#define SQLITE_STATUS_PAGECACHE_USED 1 6939#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 6940#define SQLITE_STATUS_SCRATCH_USED 3 6941#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 6942#define SQLITE_STATUS_MALLOC_SIZE 5 6943#define SQLITE_STATUS_PARSER_STACK 6 6944#define SQLITE_STATUS_PAGECACHE_SIZE 7 6945#define SQLITE_STATUS_SCRATCH_SIZE 8 6946#define SQLITE_STATUS_MALLOC_COUNT 9 6947 6948/* 6949** CAPI3REF: Database Connection Status 6950** METHOD: sqlite3 6951** 6952** ^This interface is used to retrieve runtime status information 6953** about a single [database connection]. ^The first argument is the 6954** database connection object to be interrogated. ^The second argument 6955** is an integer constant, taken from the set of 6956** [SQLITE_DBSTATUS options], that 6957** determines the parameter to interrogate. The set of 6958** [SQLITE_DBSTATUS options] is likely 6959** to grow in future releases of SQLite. 6960** 6961** ^The current value of the requested parameter is written into *pCur 6962** and the highest instantaneous value is written into *pHiwtr. ^If 6963** the resetFlg is true, then the highest instantaneous value is 6964** reset back down to the current value. 6965** 6966** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 6967** non-zero [error code] on failure. 6968** 6969** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 6970*/ 6971int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 6972 6973/* 6974** CAPI3REF: Status Parameters for database connections 6975** KEYWORDS: {SQLITE_DBSTATUS options} 6976** 6977** These constants are the available integer "verbs" that can be passed as 6978** the second argument to the [sqlite3_db_status()] interface. 6979** 6980** New verbs may be added in future releases of SQLite. Existing verbs 6981** might be discontinued. Applications should check the return code from 6982** [sqlite3_db_status()] to make sure that the call worked. 6983** The [sqlite3_db_status()] interface will return a non-zero error code 6984** if a discontinued or unsupported verb is invoked. 6985** 6986** <dl> 6987** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 6988** <dd>This parameter returns the number of lookaside memory slots currently 6989** checked out.</dd>)^ 6990** 6991** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 6992** <dd>This parameter returns the number malloc attempts that were 6993** satisfied using lookaside memory. Only the high-water value is meaningful; 6994** the current value is always zero.)^ 6995** 6996** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 6997** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 6998** <dd>This parameter returns the number malloc attempts that might have 6999** been satisfied using lookaside memory but failed due to the amount of 7000** memory requested being larger than the lookaside slot size. 7001** Only the high-water value is meaningful; 7002** the current value is always zero.)^ 7003** 7004** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 7005** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 7006** <dd>This parameter returns the number malloc attempts that might have 7007** been satisfied using lookaside memory but failed due to all lookaside 7008** memory already being in use. 7009** Only the high-water value is meaningful; 7010** the current value is always zero.)^ 7011** 7012** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 7013** <dd>This parameter returns the approximate number of bytes of heap 7014** memory used by all pager caches associated with the database connection.)^ 7015** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 7016** 7017** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 7018** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 7019** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 7020** pager cache is shared between two or more connections the bytes of heap 7021** memory used by that pager cache is divided evenly between the attached 7022** connections.)^ In other words, if none of the pager caches associated 7023** with the database connection are shared, this request returns the same 7024** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 7025** shared, the value returned by this call will be smaller than that returned 7026** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 7027** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 7028** 7029** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 7030** <dd>This parameter returns the approximate number of bytes of heap 7031** memory used to store the schema for all databases associated 7032** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 7033** ^The full amount of memory used by the schemas is reported, even if the 7034** schema memory is shared with other database connections due to 7035** [shared cache mode] being enabled. 7036** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 7037** 7038** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 7039** <dd>This parameter returns the approximate number of bytes of heap 7040** and lookaside memory used by all prepared statements associated with 7041** the database connection.)^ 7042** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 7043** </dd> 7044** 7045** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 7046** <dd>This parameter returns the number of pager cache hits that have 7047** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 7048** is always 0. 7049** </dd> 7050** 7051** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 7052** <dd>This parameter returns the number of pager cache misses that have 7053** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 7054** is always 0. 7055** </dd> 7056** 7057** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 7058** <dd>This parameter returns the number of dirty cache entries that have 7059** been written to disk. Specifically, the number of pages written to the 7060** wal file in wal mode databases, or the number of pages written to the 7061** database file in rollback mode databases. Any pages written as part of 7062** transaction rollback or database recovery operations are not included. 7063** If an IO or other error occurs while writing a page to disk, the effect 7064** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 7065** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 7066** </dd> 7067** 7068** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 7069** <dd>This parameter returns zero for the current value if and only if 7070** all foreign key constraints (deferred or immediate) have been 7071** resolved.)^ ^The highwater mark is always 0. 7072** </dd> 7073** </dl> 7074*/ 7075#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 7076#define SQLITE_DBSTATUS_CACHE_USED 1 7077#define SQLITE_DBSTATUS_SCHEMA_USED 2 7078#define SQLITE_DBSTATUS_STMT_USED 3 7079#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 7080#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 7081#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 7082#define SQLITE_DBSTATUS_CACHE_HIT 7 7083#define SQLITE_DBSTATUS_CACHE_MISS 8 7084#define SQLITE_DBSTATUS_CACHE_WRITE 9 7085#define SQLITE_DBSTATUS_DEFERRED_FKS 10 7086#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 7087#define SQLITE_DBSTATUS_MAX 11 /* Largest defined DBSTATUS */ 7088 7089 7090/* 7091** CAPI3REF: Prepared Statement Status 7092** METHOD: sqlite3_stmt 7093** 7094** ^(Each prepared statement maintains various 7095** [SQLITE_STMTSTATUS counters] that measure the number 7096** of times it has performed specific operations.)^ These counters can 7097** be used to monitor the performance characteristics of the prepared 7098** statements. For example, if the number of table steps greatly exceeds 7099** the number of table searches or result rows, that would tend to indicate 7100** that the prepared statement is using a full table scan rather than 7101** an index. 7102** 7103** ^(This interface is used to retrieve and reset counter values from 7104** a [prepared statement]. The first argument is the prepared statement 7105** object to be interrogated. The second argument 7106** is an integer code for a specific [SQLITE_STMTSTATUS counter] 7107** to be interrogated.)^ 7108** ^The current value of the requested counter is returned. 7109** ^If the resetFlg is true, then the counter is reset to zero after this 7110** interface call returns. 7111** 7112** See also: [sqlite3_status()] and [sqlite3_db_status()]. 7113*/ 7114int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 7115 7116/* 7117** CAPI3REF: Status Parameters for prepared statements 7118** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 7119** 7120** These preprocessor macros define integer codes that name counter 7121** values associated with the [sqlite3_stmt_status()] interface. 7122** The meanings of the various counters are as follows: 7123** 7124** <dl> 7125** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 7126** <dd>^This is the number of times that SQLite has stepped forward in 7127** a table as part of a full table scan. Large numbers for this counter 7128** may indicate opportunities for performance improvement through 7129** careful use of indices.</dd> 7130** 7131** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 7132** <dd>^This is the number of sort operations that have occurred. 7133** A non-zero value in this counter may indicate an opportunity to 7134** improvement performance through careful use of indices.</dd> 7135** 7136** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 7137** <dd>^This is the number of rows inserted into transient indices that 7138** were created automatically in order to help joins run faster. 7139** A non-zero value in this counter may indicate an opportunity to 7140** improvement performance by adding permanent indices that do not 7141** need to be reinitialized each time the statement is run.</dd> 7142** 7143** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 7144** <dd>^This is the number of virtual machine operations executed 7145** by the prepared statement if that number is less than or equal 7146** to 2147483647. The number of virtual machine operations can be 7147** used as a proxy for the total work done by the prepared statement. 7148** If the number of virtual machine operations exceeds 2147483647 7149** then the value returned by this statement status code is undefined. 7150** 7151** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 7152** <dd>^This is the number of times that the prepare statement has been 7153** automatically regenerated due to schema changes or change to 7154** [bound parameters] that might affect the query plan. 7155** 7156** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 7157** <dd>^This is the number of times that the prepared statement has 7158** been run. A single "run" for the purposes of this counter is one 7159** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 7160** The counter is incremented on the first [sqlite3_step()] call of each 7161** cycle. 7162** 7163** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 7164** <dd>^This is the approximate number of bytes of heap memory 7165** used to store the prepared statement. ^This value is not actually 7166** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 7167** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 7168** </dd> 7169** </dl> 7170*/ 7171#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 7172#define SQLITE_STMTSTATUS_SORT 2 7173#define SQLITE_STMTSTATUS_AUTOINDEX 3 7174#define SQLITE_STMTSTATUS_VM_STEP 4 7175#define SQLITE_STMTSTATUS_REPREPARE 5 7176#define SQLITE_STMTSTATUS_RUN 6 7177#define SQLITE_STMTSTATUS_MEMUSED 99 7178 7179/* 7180** CAPI3REF: Custom Page Cache Object 7181** 7182** The sqlite3_pcache type is opaque. It is implemented by 7183** the pluggable module. The SQLite core has no knowledge of 7184** its size or internal structure and never deals with the 7185** sqlite3_pcache object except by holding and passing pointers 7186** to the object. 7187** 7188** See [sqlite3_pcache_methods2] for additional information. 7189*/ 7190typedef struct sqlite3_pcache sqlite3_pcache; 7191 7192/* 7193** CAPI3REF: Custom Page Cache Object 7194** 7195** The sqlite3_pcache_page object represents a single page in the 7196** page cache. The page cache will allocate instances of this 7197** object. Various methods of the page cache use pointers to instances 7198** of this object as parameters or as their return value. 7199** 7200** See [sqlite3_pcache_methods2] for additional information. 7201*/ 7202typedef struct sqlite3_pcache_page sqlite3_pcache_page; 7203struct sqlite3_pcache_page { 7204 void *pBuf; /* The content of the page */ 7205 void *pExtra; /* Extra information associated with the page */ 7206}; 7207 7208/* 7209** CAPI3REF: Application Defined Page Cache. 7210** KEYWORDS: {page cache} 7211** 7212** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 7213** register an alternative page cache implementation by passing in an 7214** instance of the sqlite3_pcache_methods2 structure.)^ 7215** In many applications, most of the heap memory allocated by 7216** SQLite is used for the page cache. 7217** By implementing a 7218** custom page cache using this API, an application can better control 7219** the amount of memory consumed by SQLite, the way in which 7220** that memory is allocated and released, and the policies used to 7221** determine exactly which parts of a database file are cached and for 7222** how long. 7223** 7224** The alternative page cache mechanism is an 7225** extreme measure that is only needed by the most demanding applications. 7226** The built-in page cache is recommended for most uses. 7227** 7228** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 7229** internal buffer by SQLite within the call to [sqlite3_config]. Hence 7230** the application may discard the parameter after the call to 7231** [sqlite3_config()] returns.)^ 7232** 7233** [[the xInit() page cache method]] 7234** ^(The xInit() method is called once for each effective 7235** call to [sqlite3_initialize()])^ 7236** (usually only once during the lifetime of the process). ^(The xInit() 7237** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 7238** The intent of the xInit() method is to set up global data structures 7239** required by the custom page cache implementation. 7240** ^(If the xInit() method is NULL, then the 7241** built-in default page cache is used instead of the application defined 7242** page cache.)^ 7243** 7244** [[the xShutdown() page cache method]] 7245** ^The xShutdown() method is called by [sqlite3_shutdown()]. 7246** It can be used to clean up 7247** any outstanding resources before process shutdown, if required. 7248** ^The xShutdown() method may be NULL. 7249** 7250** ^SQLite automatically serializes calls to the xInit method, 7251** so the xInit method need not be threadsafe. ^The 7252** xShutdown method is only called from [sqlite3_shutdown()] so it does 7253** not need to be threadsafe either. All other methods must be threadsafe 7254** in multithreaded applications. 7255** 7256** ^SQLite will never invoke xInit() more than once without an intervening 7257** call to xShutdown(). 7258** 7259** [[the xCreate() page cache methods]] 7260** ^SQLite invokes the xCreate() method to construct a new cache instance. 7261** SQLite will typically create one cache instance for each open database file, 7262** though this is not guaranteed. ^The 7263** first parameter, szPage, is the size in bytes of the pages that must 7264** be allocated by the cache. ^szPage will always a power of two. ^The 7265** second parameter szExtra is a number of bytes of extra storage 7266** associated with each page cache entry. ^The szExtra parameter will 7267** a number less than 250. SQLite will use the 7268** extra szExtra bytes on each page to store metadata about the underlying 7269** database page on disk. The value passed into szExtra depends 7270** on the SQLite version, the target platform, and how SQLite was compiled. 7271** ^The third argument to xCreate(), bPurgeable, is true if the cache being 7272** created will be used to cache database pages of a file stored on disk, or 7273** false if it is used for an in-memory database. The cache implementation 7274** does not have to do anything special based with the value of bPurgeable; 7275** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 7276** never invoke xUnpin() except to deliberately delete a page. 7277** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 7278** false will always have the "discard" flag set to true. 7279** ^Hence, a cache created with bPurgeable false will 7280** never contain any unpinned pages. 7281** 7282** [[the xCachesize() page cache method]] 7283** ^(The xCachesize() method may be called at any time by SQLite to set the 7284** suggested maximum cache-size (number of pages stored by) the cache 7285** instance passed as the first argument. This is the value configured using 7286** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 7287** parameter, the implementation is not required to do anything with this 7288** value; it is advisory only. 7289** 7290** [[the xPagecount() page cache methods]] 7291** The xPagecount() method must return the number of pages currently 7292** stored in the cache, both pinned and unpinned. 7293** 7294** [[the xFetch() page cache methods]] 7295** The xFetch() method locates a page in the cache and returns a pointer to 7296** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 7297** The pBuf element of the returned sqlite3_pcache_page object will be a 7298** pointer to a buffer of szPage bytes used to store the content of a 7299** single database page. The pExtra element of sqlite3_pcache_page will be 7300** a pointer to the szExtra bytes of extra storage that SQLite has requested 7301** for each entry in the page cache. 7302** 7303** The page to be fetched is determined by the key. ^The minimum key value 7304** is 1. After it has been retrieved using xFetch, the page is considered 7305** to be "pinned". 7306** 7307** If the requested page is already in the page cache, then the page cache 7308** implementation must return a pointer to the page buffer with its content 7309** intact. If the requested page is not already in the cache, then the 7310** cache implementation should use the value of the createFlag 7311** parameter to help it determined what action to take: 7312** 7313** <table border=1 width=85% align=center> 7314** <tr><th> createFlag <th> Behavior when page is not already in cache 7315** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 7316** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 7317** Otherwise return NULL. 7318** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 7319** NULL if allocating a new page is effectively impossible. 7320** </table> 7321** 7322** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 7323** will only use a createFlag of 2 after a prior call with a createFlag of 1 7324** failed.)^ In between the to xFetch() calls, SQLite may 7325** attempt to unpin one or more cache pages by spilling the content of 7326** pinned pages to disk and synching the operating system disk cache. 7327** 7328** [[the xUnpin() page cache method]] 7329** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 7330** as its second argument. If the third parameter, discard, is non-zero, 7331** then the page must be evicted from the cache. 7332** ^If the discard parameter is 7333** zero, then the page may be discarded or retained at the discretion of 7334** page cache implementation. ^The page cache implementation 7335** may choose to evict unpinned pages at any time. 7336** 7337** The cache must not perform any reference counting. A single 7338** call to xUnpin() unpins the page regardless of the number of prior calls 7339** to xFetch(). 7340** 7341** [[the xRekey() page cache methods]] 7342** The xRekey() method is used to change the key value associated with the 7343** page passed as the second argument. If the cache 7344** previously contains an entry associated with newKey, it must be 7345** discarded. ^Any prior cache entry associated with newKey is guaranteed not 7346** to be pinned. 7347** 7348** When SQLite calls the xTruncate() method, the cache must discard all 7349** existing cache entries with page numbers (keys) greater than or equal 7350** to the value of the iLimit parameter passed to xTruncate(). If any 7351** of these pages are pinned, they are implicitly unpinned, meaning that 7352** they can be safely discarded. 7353** 7354** [[the xDestroy() page cache method]] 7355** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 7356** All resources associated with the specified cache should be freed. ^After 7357** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 7358** handle invalid, and will not use it with any other sqlite3_pcache_methods2 7359** functions. 7360** 7361** [[the xShrink() page cache method]] 7362** ^SQLite invokes the xShrink() method when it wants the page cache to 7363** free up as much of heap memory as possible. The page cache implementation 7364** is not obligated to free any memory, but well-behaved implementations should 7365** do their best. 7366*/ 7367typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 7368struct sqlite3_pcache_methods2 { 7369 int iVersion; 7370 void *pArg; 7371 int (*xInit)(void*); 7372 void (*xShutdown)(void*); 7373 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 7374 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7375 int (*xPagecount)(sqlite3_pcache*); 7376 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7377 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 7378 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 7379 unsigned oldKey, unsigned newKey); 7380 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7381 void (*xDestroy)(sqlite3_pcache*); 7382 void (*xShrink)(sqlite3_pcache*); 7383}; 7384 7385/* 7386** This is the obsolete pcache_methods object that has now been replaced 7387** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 7388** retained in the header file for backwards compatibility only. 7389*/ 7390typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 7391struct sqlite3_pcache_methods { 7392 void *pArg; 7393 int (*xInit)(void*); 7394 void (*xShutdown)(void*); 7395 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 7396 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7397 int (*xPagecount)(sqlite3_pcache*); 7398 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7399 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 7400 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 7401 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7402 void (*xDestroy)(sqlite3_pcache*); 7403}; 7404 7405 7406/* 7407** CAPI3REF: Online Backup Object 7408** 7409** The sqlite3_backup object records state information about an ongoing 7410** online backup operation. ^The sqlite3_backup object is created by 7411** a call to [sqlite3_backup_init()] and is destroyed by a call to 7412** [sqlite3_backup_finish()]. 7413** 7414** See Also: [Using the SQLite Online Backup API] 7415*/ 7416typedef struct sqlite3_backup sqlite3_backup; 7417 7418/* 7419** CAPI3REF: Online Backup API. 7420** 7421** The backup API copies the content of one database into another. 7422** It is useful either for creating backups of databases or 7423** for copying in-memory databases to or from persistent files. 7424** 7425** See Also: [Using the SQLite Online Backup API] 7426** 7427** ^SQLite holds a write transaction open on the destination database file 7428** for the duration of the backup operation. 7429** ^The source database is read-locked only while it is being read; 7430** it is not locked continuously for the entire backup operation. 7431** ^Thus, the backup may be performed on a live source database without 7432** preventing other database connections from 7433** reading or writing to the source database while the backup is underway. 7434** 7435** ^(To perform a backup operation: 7436** <ol> 7437** <li><b>sqlite3_backup_init()</b> is called once to initialize the 7438** backup, 7439** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 7440** the data between the two databases, and finally 7441** <li><b>sqlite3_backup_finish()</b> is called to release all resources 7442** associated with the backup operation. 7443** </ol>)^ 7444** There should be exactly one call to sqlite3_backup_finish() for each 7445** successful call to sqlite3_backup_init(). 7446** 7447** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 7448** 7449** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 7450** [database connection] associated with the destination database 7451** and the database name, respectively. 7452** ^The database name is "main" for the main database, "temp" for the 7453** temporary database, or the name specified after the AS keyword in 7454** an [ATTACH] statement for an attached database. 7455** ^The S and M arguments passed to 7456** sqlite3_backup_init(D,N,S,M) identify the [database connection] 7457** and database name of the source database, respectively. 7458** ^The source and destination [database connections] (parameters S and D) 7459** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 7460** an error. 7461** 7462** ^A call to sqlite3_backup_init() will fail, returning NULL, if 7463** there is already a read or read-write transaction open on the 7464** destination database. 7465** 7466** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 7467** returned and an error code and error message are stored in the 7468** destination [database connection] D. 7469** ^The error code and message for the failed call to sqlite3_backup_init() 7470** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 7471** [sqlite3_errmsg16()] functions. 7472** ^A successful call to sqlite3_backup_init() returns a pointer to an 7473** [sqlite3_backup] object. 7474** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 7475** sqlite3_backup_finish() functions to perform the specified backup 7476** operation. 7477** 7478** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 7479** 7480** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 7481** the source and destination databases specified by [sqlite3_backup] object B. 7482** ^If N is negative, all remaining source pages are copied. 7483** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 7484** are still more pages to be copied, then the function returns [SQLITE_OK]. 7485** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 7486** from source to destination, then it returns [SQLITE_DONE]. 7487** ^If an error occurs while running sqlite3_backup_step(B,N), 7488** then an [error code] is returned. ^As well as [SQLITE_OK] and 7489** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 7490** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 7491** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 7492** 7493** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 7494** <ol> 7495** <li> the destination database was opened read-only, or 7496** <li> the destination database is using write-ahead-log journaling 7497** and the destination and source page sizes differ, or 7498** <li> the destination database is an in-memory database and the 7499** destination and source page sizes differ. 7500** </ol>)^ 7501** 7502** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 7503** the [sqlite3_busy_handler | busy-handler function] 7504** is invoked (if one is specified). ^If the 7505** busy-handler returns non-zero before the lock is available, then 7506** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 7507** sqlite3_backup_step() can be retried later. ^If the source 7508** [database connection] 7509** is being used to write to the source database when sqlite3_backup_step() 7510** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 7511** case the call to sqlite3_backup_step() can be retried later on. ^(If 7512** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 7513** [SQLITE_READONLY] is returned, then 7514** there is no point in retrying the call to sqlite3_backup_step(). These 7515** errors are considered fatal.)^ The application must accept 7516** that the backup operation has failed and pass the backup operation handle 7517** to the sqlite3_backup_finish() to release associated resources. 7518** 7519** ^The first call to sqlite3_backup_step() obtains an exclusive lock 7520** on the destination file. ^The exclusive lock is not released until either 7521** sqlite3_backup_finish() is called or the backup operation is complete 7522** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 7523** sqlite3_backup_step() obtains a [shared lock] on the source database that 7524** lasts for the duration of the sqlite3_backup_step() call. 7525** ^Because the source database is not locked between calls to 7526** sqlite3_backup_step(), the source database may be modified mid-way 7527** through the backup process. ^If the source database is modified by an 7528** external process or via a database connection other than the one being 7529** used by the backup operation, then the backup will be automatically 7530** restarted by the next call to sqlite3_backup_step(). ^If the source 7531** database is modified by the using the same database connection as is used 7532** by the backup operation, then the backup database is automatically 7533** updated at the same time. 7534** 7535** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 7536** 7537** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 7538** application wishes to abandon the backup operation, the application 7539** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 7540** ^The sqlite3_backup_finish() interfaces releases all 7541** resources associated with the [sqlite3_backup] object. 7542** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 7543** active write-transaction on the destination database is rolled back. 7544** The [sqlite3_backup] object is invalid 7545** and may not be used following a call to sqlite3_backup_finish(). 7546** 7547** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 7548** sqlite3_backup_step() errors occurred, regardless or whether or not 7549** sqlite3_backup_step() completed. 7550** ^If an out-of-memory condition or IO error occurred during any prior 7551** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 7552** sqlite3_backup_finish() returns the corresponding [error code]. 7553** 7554** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 7555** is not a permanent error and does not affect the return value of 7556** sqlite3_backup_finish(). 7557** 7558** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 7559** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 7560** 7561** ^The sqlite3_backup_remaining() routine returns the number of pages still 7562** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 7563** ^The sqlite3_backup_pagecount() routine returns the total number of pages 7564** in the source database at the conclusion of the most recent 7565** sqlite3_backup_step(). 7566** ^(The values returned by these functions are only updated by 7567** sqlite3_backup_step(). If the source database is modified in a way that 7568** changes the size of the source database or the number of pages remaining, 7569** those changes are not reflected in the output of sqlite3_backup_pagecount() 7570** and sqlite3_backup_remaining() until after the next 7571** sqlite3_backup_step().)^ 7572** 7573** <b>Concurrent Usage of Database Handles</b> 7574** 7575** ^The source [database connection] may be used by the application for other 7576** purposes while a backup operation is underway or being initialized. 7577** ^If SQLite is compiled and configured to support threadsafe database 7578** connections, then the source database connection may be used concurrently 7579** from within other threads. 7580** 7581** However, the application must guarantee that the destination 7582** [database connection] is not passed to any other API (by any thread) after 7583** sqlite3_backup_init() is called and before the corresponding call to 7584** sqlite3_backup_finish(). SQLite does not currently check to see 7585** if the application incorrectly accesses the destination [database connection] 7586** and so no error code is reported, but the operations may malfunction 7587** nevertheless. Use of the destination database connection while a 7588** backup is in progress might also also cause a mutex deadlock. 7589** 7590** If running in [shared cache mode], the application must 7591** guarantee that the shared cache used by the destination database 7592** is not accessed while the backup is running. In practice this means 7593** that the application must guarantee that the disk file being 7594** backed up to is not accessed by any connection within the process, 7595** not just the specific connection that was passed to sqlite3_backup_init(). 7596** 7597** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7598** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7599** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7600** APIs are not strictly speaking threadsafe. If they are invoked at the 7601** same time as another thread is invoking sqlite3_backup_step() it is 7602** possible that they return invalid values. 7603*/ 7604sqlite3_backup *sqlite3_backup_init( 7605 sqlite3 *pDest, /* Destination database handle */ 7606 const char *zDestName, /* Destination database name */ 7607 sqlite3 *pSource, /* Source database handle */ 7608 const char *zSourceName /* Source database name */ 7609); 7610int sqlite3_backup_step(sqlite3_backup *p, int nPage); 7611int sqlite3_backup_finish(sqlite3_backup *p); 7612int sqlite3_backup_remaining(sqlite3_backup *p); 7613int sqlite3_backup_pagecount(sqlite3_backup *p); 7614 7615/* 7616** CAPI3REF: Unlock Notification 7617** METHOD: sqlite3 7618** 7619** ^When running in shared-cache mode, a database operation may fail with 7620** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7621** individual tables within the shared-cache cannot be obtained. See 7622** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7623** ^This API may be used to register a callback that SQLite will invoke 7624** when the connection currently holding the required lock relinquishes it. 7625** ^This API is only available if the library was compiled with the 7626** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7627** 7628** See Also: [Using the SQLite Unlock Notification Feature]. 7629** 7630** ^Shared-cache locks are released when a database connection concludes 7631** its current transaction, either by committing it or rolling it back. 7632** 7633** ^When a connection (known as the blocked connection) fails to obtain a 7634** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7635** identity of the database connection (the blocking connection) that 7636** has locked the required resource is stored internally. ^After an 7637** application receives an SQLITE_LOCKED error, it may call the 7638** sqlite3_unlock_notify() method with the blocked connection handle as 7639** the first argument to register for a callback that will be invoked 7640** when the blocking connections current transaction is concluded. ^The 7641** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7642** call that concludes the blocking connections transaction. 7643** 7644** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7645** there is a chance that the blocking connection will have already 7646** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7647** If this happens, then the specified callback is invoked immediately, 7648** from within the call to sqlite3_unlock_notify().)^ 7649** 7650** ^If the blocked connection is attempting to obtain a write-lock on a 7651** shared-cache table, and more than one other connection currently holds 7652** a read-lock on the same table, then SQLite arbitrarily selects one of 7653** the other connections to use as the blocking connection. 7654** 7655** ^(There may be at most one unlock-notify callback registered by a 7656** blocked connection. If sqlite3_unlock_notify() is called when the 7657** blocked connection already has a registered unlock-notify callback, 7658** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7659** called with a NULL pointer as its second argument, then any existing 7660** unlock-notify callback is canceled. ^The blocked connections 7661** unlock-notify callback may also be canceled by closing the blocked 7662** connection using [sqlite3_close()]. 7663** 7664** The unlock-notify callback is not reentrant. If an application invokes 7665** any sqlite3_xxx API functions from within an unlock-notify callback, a 7666** crash or deadlock may be the result. 7667** 7668** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7669** returns SQLITE_OK. 7670** 7671** <b>Callback Invocation Details</b> 7672** 7673** When an unlock-notify callback is registered, the application provides a 7674** single void* pointer that is passed to the callback when it is invoked. 7675** However, the signature of the callback function allows SQLite to pass 7676** it an array of void* context pointers. The first argument passed to 7677** an unlock-notify callback is a pointer to an array of void* pointers, 7678** and the second is the number of entries in the array. 7679** 7680** When a blocking connections transaction is concluded, there may be 7681** more than one blocked connection that has registered for an unlock-notify 7682** callback. ^If two or more such blocked connections have specified the 7683** same callback function, then instead of invoking the callback function 7684** multiple times, it is invoked once with the set of void* context pointers 7685** specified by the blocked connections bundled together into an array. 7686** This gives the application an opportunity to prioritize any actions 7687** related to the set of unblocked database connections. 7688** 7689** <b>Deadlock Detection</b> 7690** 7691** Assuming that after registering for an unlock-notify callback a 7692** database waits for the callback to be issued before taking any further 7693** action (a reasonable assumption), then using this API may cause the 7694** application to deadlock. For example, if connection X is waiting for 7695** connection Y's transaction to be concluded, and similarly connection 7696** Y is waiting on connection X's transaction, then neither connection 7697** will proceed and the system may remain deadlocked indefinitely. 7698** 7699** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7700** detection. ^If a given call to sqlite3_unlock_notify() would put the 7701** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7702** unlock-notify callback is registered. The system is said to be in 7703** a deadlocked state if connection A has registered for an unlock-notify 7704** callback on the conclusion of connection B's transaction, and connection 7705** B has itself registered for an unlock-notify callback when connection 7706** A's transaction is concluded. ^Indirect deadlock is also detected, so 7707** the system is also considered to be deadlocked if connection B has 7708** registered for an unlock-notify callback on the conclusion of connection 7709** C's transaction, where connection C is waiting on connection A. ^Any 7710** number of levels of indirection are allowed. 7711** 7712** <b>The "DROP TABLE" Exception</b> 7713** 7714** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7715** always appropriate to call sqlite3_unlock_notify(). There is however, 7716** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7717** SQLite checks if there are any currently executing SELECT statements 7718** that belong to the same connection. If there are, SQLITE_LOCKED is 7719** returned. In this case there is no "blocking connection", so invoking 7720** sqlite3_unlock_notify() results in the unlock-notify callback being 7721** invoked immediately. If the application then re-attempts the "DROP TABLE" 7722** or "DROP INDEX" query, an infinite loop might be the result. 7723** 7724** One way around this problem is to check the extended error code returned 7725** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7726** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7727** the special "DROP TABLE/INDEX" case, the extended error code is just 7728** SQLITE_LOCKED.)^ 7729*/ 7730int sqlite3_unlock_notify( 7731 sqlite3 *pBlocked, /* Waiting connection */ 7732 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7733 void *pNotifyArg /* Argument to pass to xNotify */ 7734); 7735 7736 7737/* 7738** CAPI3REF: String Comparison 7739** 7740** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7741** and extensions to compare the contents of two buffers containing UTF-8 7742** strings in a case-independent fashion, using the same definition of "case 7743** independence" that SQLite uses internally when comparing identifiers. 7744*/ 7745int sqlite3_stricmp(const char *, const char *); 7746int sqlite3_strnicmp(const char *, const char *, int); 7747 7748/* 7749** CAPI3REF: String Globbing 7750* 7751** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 7752** string X matches the [GLOB] pattern P. 7753** ^The definition of [GLOB] pattern matching used in 7754** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7755** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 7756** is case sensitive. 7757** 7758** Note that this routine returns zero on a match and non-zero if the strings 7759** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7760** 7761** See also: [sqlite3_strlike()]. 7762*/ 7763int sqlite3_strglob(const char *zGlob, const char *zStr); 7764 7765/* 7766** CAPI3REF: String LIKE Matching 7767* 7768** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 7769** string X matches the [LIKE] pattern P with escape character E. 7770** ^The definition of [LIKE] pattern matching used in 7771** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 7772** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 7773** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 7774** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 7775** insensitive - equivalent upper and lower case ASCII characters match 7776** one another. 7777** 7778** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 7779** only ASCII characters are case folded. 7780** 7781** Note that this routine returns zero on a match and non-zero if the strings 7782** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7783** 7784** See also: [sqlite3_strglob()]. 7785*/ 7786int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 7787 7788/* 7789** CAPI3REF: Error Logging Interface 7790** 7791** ^The [sqlite3_log()] interface writes a message into the [error log] 7792** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7793** ^If logging is enabled, the zFormat string and subsequent arguments are 7794** used with [sqlite3_snprintf()] to generate the final output string. 7795** 7796** The sqlite3_log() interface is intended for use by extensions such as 7797** virtual tables, collating functions, and SQL functions. While there is 7798** nothing to prevent an application from calling sqlite3_log(), doing so 7799** is considered bad form. 7800** 7801** The zFormat string must not be NULL. 7802** 7803** To avoid deadlocks and other threading problems, the sqlite3_log() routine 7804** will not use dynamically allocated memory. The log message is stored in 7805** a fixed-length buffer on the stack. If the log message is longer than 7806** a few hundred characters, it will be truncated to the length of the 7807** buffer. 7808*/ 7809void sqlite3_log(int iErrCode, const char *zFormat, ...); 7810 7811/* 7812** CAPI3REF: Write-Ahead Log Commit Hook 7813** METHOD: sqlite3 7814** 7815** ^The [sqlite3_wal_hook()] function is used to register a callback that 7816** is invoked each time data is committed to a database in wal mode. 7817** 7818** ^(The callback is invoked by SQLite after the commit has taken place and 7819** the associated write-lock on the database released)^, so the implementation 7820** may read, write or [checkpoint] the database as required. 7821** 7822** ^The first parameter passed to the callback function when it is invoked 7823** is a copy of the third parameter passed to sqlite3_wal_hook() when 7824** registering the callback. ^The second is a copy of the database handle. 7825** ^The third parameter is the name of the database that was written to - 7826** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 7827** is the number of pages currently in the write-ahead log file, 7828** including those that were just committed. 7829** 7830** The callback function should normally return [SQLITE_OK]. ^If an error 7831** code is returned, that error will propagate back up through the 7832** SQLite code base to cause the statement that provoked the callback 7833** to report an error, though the commit will have still occurred. If the 7834** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 7835** that does not correspond to any valid SQLite error code, the results 7836** are undefined. 7837** 7838** A single database handle may have at most a single write-ahead log callback 7839** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 7840** previously registered write-ahead log callback. ^Note that the 7841** [sqlite3_wal_autocheckpoint()] interface and the 7842** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 7843** overwrite any prior [sqlite3_wal_hook()] settings. 7844*/ 7845void *sqlite3_wal_hook( 7846 sqlite3*, 7847 int(*)(void *,sqlite3*,const char*,int), 7848 void* 7849); 7850 7851/* 7852** CAPI3REF: Configure an auto-checkpoint 7853** METHOD: sqlite3 7854** 7855** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 7856** [sqlite3_wal_hook()] that causes any database on [database connection] D 7857** to automatically [checkpoint] 7858** after committing a transaction if there are N or 7859** more frames in the [write-ahead log] file. ^Passing zero or 7860** a negative value as the nFrame parameter disables automatic 7861** checkpoints entirely. 7862** 7863** ^The callback registered by this function replaces any existing callback 7864** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 7865** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 7866** configured by this function. 7867** 7868** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 7869** from SQL. 7870** 7871** ^Checkpoints initiated by this mechanism are 7872** [sqlite3_wal_checkpoint_v2|PASSIVE]. 7873** 7874** ^Every new [database connection] defaults to having the auto-checkpoint 7875** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 7876** pages. The use of this interface 7877** is only necessary if the default setting is found to be suboptimal 7878** for a particular application. 7879*/ 7880int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 7881 7882/* 7883** CAPI3REF: Checkpoint a database 7884** METHOD: sqlite3 7885** 7886** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 7887** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 7888** 7889** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 7890** [write-ahead log] for database X on [database connection] D to be 7891** transferred into the database file and for the write-ahead log to 7892** be reset. See the [checkpointing] documentation for addition 7893** information. 7894** 7895** This interface used to be the only way to cause a checkpoint to 7896** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 7897** interface was added. This interface is retained for backwards 7898** compatibility and as a convenience for applications that need to manually 7899** start a callback but which do not need the full power (and corresponding 7900** complication) of [sqlite3_wal_checkpoint_v2()]. 7901*/ 7902int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 7903 7904/* 7905** CAPI3REF: Checkpoint a database 7906** METHOD: sqlite3 7907** 7908** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 7909** operation on database X of [database connection] D in mode M. Status 7910** information is written back into integers pointed to by L and C.)^ 7911** ^(The M parameter must be a valid [checkpoint mode]:)^ 7912** 7913** <dl> 7914** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 7915** ^Checkpoint as many frames as possible without waiting for any database 7916** readers or writers to finish, then sync the database file if all frames 7917** in the log were checkpointed. ^The [busy-handler callback] 7918** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 7919** ^On the other hand, passive mode might leave the checkpoint unfinished 7920** if there are concurrent readers or writers. 7921** 7922** <dt>SQLITE_CHECKPOINT_FULL<dd> 7923** ^This mode blocks (it invokes the 7924** [sqlite3_busy_handler|busy-handler callback]) until there is no 7925** database writer and all readers are reading from the most recent database 7926** snapshot. ^It then checkpoints all frames in the log file and syncs the 7927** database file. ^This mode blocks new database writers while it is pending, 7928** but new database readers are allowed to continue unimpeded. 7929** 7930** <dt>SQLITE_CHECKPOINT_RESTART<dd> 7931** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 7932** that after checkpointing the log file it blocks (calls the 7933** [busy-handler callback]) 7934** until all readers are reading from the database file only. ^This ensures 7935** that the next writer will restart the log file from the beginning. 7936** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 7937** database writer attempts while it is pending, but does not impede readers. 7938** 7939** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 7940** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 7941** addition that it also truncates the log file to zero bytes just prior 7942** to a successful return. 7943** </dl> 7944** 7945** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 7946** the log file or to -1 if the checkpoint could not run because 7947** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 7948** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 7949** log file (including any that were already checkpointed before the function 7950** was called) or to -1 if the checkpoint could not run due to an error or 7951** because the database is not in WAL mode. ^Note that upon successful 7952** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 7953** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 7954** 7955** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 7956** any other process is running a checkpoint operation at the same time, the 7957** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 7958** busy-handler configured, it will not be invoked in this case. 7959** 7960** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 7961** exclusive "writer" lock on the database file. ^If the writer lock cannot be 7962** obtained immediately, and a busy-handler is configured, it is invoked and 7963** the writer lock retried until either the busy-handler returns 0 or the lock 7964** is successfully obtained. ^The busy-handler is also invoked while waiting for 7965** database readers as described above. ^If the busy-handler returns 0 before 7966** the writer lock is obtained or while waiting for database readers, the 7967** checkpoint operation proceeds from that point in the same way as 7968** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 7969** without blocking any further. ^SQLITE_BUSY is returned in this case. 7970** 7971** ^If parameter zDb is NULL or points to a zero length string, then the 7972** specified operation is attempted on all WAL databases [attached] to 7973** [database connection] db. In this case the 7974** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 7975** an SQLITE_BUSY error is encountered when processing one or more of the 7976** attached WAL databases, the operation is still attempted on any remaining 7977** attached databases and SQLITE_BUSY is returned at the end. ^If any other 7978** error occurs while processing an attached database, processing is abandoned 7979** and the error code is returned to the caller immediately. ^If no error 7980** (SQLITE_BUSY or otherwise) is encountered while processing the attached 7981** databases, SQLITE_OK is returned. 7982** 7983** ^If database zDb is the name of an attached database that is not in WAL 7984** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 7985** zDb is not NULL (or a zero length string) and is not the name of any 7986** attached database, SQLITE_ERROR is returned to the caller. 7987** 7988** ^Unless it returns SQLITE_MISUSE, 7989** the sqlite3_wal_checkpoint_v2() interface 7990** sets the error information that is queried by 7991** [sqlite3_errcode()] and [sqlite3_errmsg()]. 7992** 7993** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 7994** from SQL. 7995*/ 7996int sqlite3_wal_checkpoint_v2( 7997 sqlite3 *db, /* Database handle */ 7998 const char *zDb, /* Name of attached database (or NULL) */ 7999 int eMode, /* SQLITE_CHECKPOINT_* value */ 8000 int *pnLog, /* OUT: Size of WAL log in frames */ 8001 int *pnCkpt /* OUT: Total number of frames checkpointed */ 8002); 8003 8004/* 8005** CAPI3REF: Checkpoint Mode Values 8006** KEYWORDS: {checkpoint mode} 8007** 8008** These constants define all valid values for the "checkpoint mode" passed 8009** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 8010** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 8011** meaning of each of these checkpoint modes. 8012*/ 8013#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 8014#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 8015#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 8016#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 8017 8018/* 8019** CAPI3REF: Virtual Table Interface Configuration 8020** 8021** This function may be called by either the [xConnect] or [xCreate] method 8022** of a [virtual table] implementation to configure 8023** various facets of the virtual table interface. 8024** 8025** If this interface is invoked outside the context of an xConnect or 8026** xCreate virtual table method then the behavior is undefined. 8027** 8028** At present, there is only one option that may be configured using 8029** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 8030** may be added in the future. 8031*/ 8032int sqlite3_vtab_config(sqlite3*, int op, ...); 8033 8034/* 8035** CAPI3REF: Virtual Table Configuration Options 8036** 8037** These macros define the various options to the 8038** [sqlite3_vtab_config()] interface that [virtual table] implementations 8039** can use to customize and optimize their behavior. 8040** 8041** <dl> 8042** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 8043** <dd>Calls of the form 8044** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 8045** where X is an integer. If X is zero, then the [virtual table] whose 8046** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 8047** support constraints. In this configuration (which is the default) if 8048** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 8049** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 8050** specified as part of the users SQL statement, regardless of the actual 8051** ON CONFLICT mode specified. 8052** 8053** If X is non-zero, then the virtual table implementation guarantees 8054** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 8055** any modifications to internal or persistent data structures have been made. 8056** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 8057** is able to roll back a statement or database transaction, and abandon 8058** or continue processing the current SQL statement as appropriate. 8059** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 8060** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 8061** had been ABORT. 8062** 8063** Virtual table implementations that are required to handle OR REPLACE 8064** must do so within the [xUpdate] method. If a call to the 8065** [sqlite3_vtab_on_conflict()] function indicates that the current ON 8066** CONFLICT policy is REPLACE, the virtual table implementation should 8067** silently replace the appropriate rows within the xUpdate callback and 8068** return SQLITE_OK. Or, if this is not possible, it may return 8069** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 8070** constraint handling. 8071** </dl> 8072*/ 8073#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 8074 8075/* 8076** CAPI3REF: Determine The Virtual Table Conflict Policy 8077** 8078** This function may only be called from within a call to the [xUpdate] method 8079** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 8080** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 8081** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 8082** of the SQL statement that triggered the call to the [xUpdate] method of the 8083** [virtual table]. 8084*/ 8085int sqlite3_vtab_on_conflict(sqlite3 *); 8086 8087/* 8088** CAPI3REF: Conflict resolution modes 8089** KEYWORDS: {conflict resolution mode} 8090** 8091** These constants are returned by [sqlite3_vtab_on_conflict()] to 8092** inform a [virtual table] implementation what the [ON CONFLICT] mode 8093** is for the SQL statement being evaluated. 8094** 8095** Note that the [SQLITE_IGNORE] constant is also used as a potential 8096** return value from the [sqlite3_set_authorizer()] callback and that 8097** [SQLITE_ABORT] is also a [result code]. 8098*/ 8099#define SQLITE_ROLLBACK 1 8100/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 8101#define SQLITE_FAIL 3 8102/* #define SQLITE_ABORT 4 // Also an error code */ 8103#define SQLITE_REPLACE 5 8104 8105/* 8106** CAPI3REF: Prepared Statement Scan Status Opcodes 8107** KEYWORDS: {scanstatus options} 8108** 8109** The following constants can be used for the T parameter to the 8110** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 8111** different metric for sqlite3_stmt_scanstatus() to return. 8112** 8113** When the value returned to V is a string, space to hold that string is 8114** managed by the prepared statement S and will be automatically freed when 8115** S is finalized. 8116** 8117** <dl> 8118** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 8119** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 8120** set to the total number of times that the X-th loop has run.</dd> 8121** 8122** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 8123** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 8124** to the total number of rows examined by all iterations of the X-th loop.</dd> 8125** 8126** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 8127** <dd>^The "double" variable pointed to by the T parameter will be set to the 8128** query planner's estimate for the average number of rows output from each 8129** iteration of the X-th loop. If the query planner's estimates was accurate, 8130** then this value will approximate the quotient NVISIT/NLOOP and the 8131** product of this value for all prior loops with the same SELECTID will 8132** be the NLOOP value for the current loop. 8133** 8134** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 8135** <dd>^The "const char *" variable pointed to by the T parameter will be set 8136** to a zero-terminated UTF-8 string containing the name of the index or table 8137** used for the X-th loop. 8138** 8139** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 8140** <dd>^The "const char *" variable pointed to by the T parameter will be set 8141** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 8142** description for the X-th loop. 8143** 8144** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 8145** <dd>^The "int" variable pointed to by the T parameter will be set to the 8146** "select-id" for the X-th loop. The select-id identifies which query or 8147** subquery the loop is part of. The main query has a select-id of zero. 8148** The select-id is the same value as is output in the first column 8149** of an [EXPLAIN QUERY PLAN] query. 8150** </dl> 8151*/ 8152#define SQLITE_SCANSTAT_NLOOP 0 8153#define SQLITE_SCANSTAT_NVISIT 1 8154#define SQLITE_SCANSTAT_EST 2 8155#define SQLITE_SCANSTAT_NAME 3 8156#define SQLITE_SCANSTAT_EXPLAIN 4 8157#define SQLITE_SCANSTAT_SELECTID 5 8158 8159/* 8160** CAPI3REF: Prepared Statement Scan Status 8161** METHOD: sqlite3_stmt 8162** 8163** This interface returns information about the predicted and measured 8164** performance for pStmt. Advanced applications can use this 8165** interface to compare the predicted and the measured performance and 8166** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 8167** 8168** Since this interface is expected to be rarely used, it is only 8169** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 8170** compile-time option. 8171** 8172** The "iScanStatusOp" parameter determines which status information to return. 8173** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 8174** of this interface is undefined. 8175** ^The requested measurement is written into a variable pointed to by 8176** the "pOut" parameter. 8177** Parameter "idx" identifies the specific loop to retrieve statistics for. 8178** Loops are numbered starting from zero. ^If idx is out of range - less than 8179** zero or greater than or equal to the total number of loops used to implement 8180** the statement - a non-zero value is returned and the variable that pOut 8181** points to is unchanged. 8182** 8183** ^Statistics might not be available for all loops in all statements. ^In cases 8184** where there exist loops with no available statistics, this function behaves 8185** as if the loop did not exist - it returns non-zero and leave the variable 8186** that pOut points to unchanged. 8187** 8188** See also: [sqlite3_stmt_scanstatus_reset()] 8189*/ 8190int sqlite3_stmt_scanstatus( 8191 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 8192 int idx, /* Index of loop to report on */ 8193 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 8194 void *pOut /* Result written here */ 8195); 8196 8197/* 8198** CAPI3REF: Zero Scan-Status Counters 8199** METHOD: sqlite3_stmt 8200** 8201** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 8202** 8203** This API is only available if the library is built with pre-processor 8204** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 8205*/ 8206void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 8207 8208/* 8209** CAPI3REF: Flush caches to disk mid-transaction 8210** 8211** ^If a write-transaction is open on [database connection] D when the 8212** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 8213** pages in the pager-cache that are not currently in use are written out 8214** to disk. A dirty page may be in use if a database cursor created by an 8215** active SQL statement is reading from it, or if it is page 1 of a database 8216** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 8217** interface flushes caches for all schemas - "main", "temp", and 8218** any [attached] databases. 8219** 8220** ^If this function needs to obtain extra database locks before dirty pages 8221** can be flushed to disk, it does so. ^If those locks cannot be obtained 8222** immediately and there is a busy-handler callback configured, it is invoked 8223** in the usual manner. ^If the required lock still cannot be obtained, then 8224** the database is skipped and an attempt made to flush any dirty pages 8225** belonging to the next (if any) database. ^If any databases are skipped 8226** because locks cannot be obtained, but no other error occurs, this 8227** function returns SQLITE_BUSY. 8228** 8229** ^If any other error occurs while flushing dirty pages to disk (for 8230** example an IO error or out-of-memory condition), then processing is 8231** abandoned and an SQLite [error code] is returned to the caller immediately. 8232** 8233** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 8234** 8235** ^This function does not set the database handle error code or message 8236** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 8237*/ 8238int sqlite3_db_cacheflush(sqlite3*); 8239 8240/* 8241** CAPI3REF: The pre-update hook. 8242** 8243** ^These interfaces are only available if SQLite is compiled using the 8244** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 8245** 8246** ^The [sqlite3_preupdate_hook()] interface registers a callback function 8247** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 8248** on a database table. 8249** ^At most one preupdate hook may be registered at a time on a single 8250** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 8251** the previous setting. 8252** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 8253** with a NULL pointer as the second parameter. 8254** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 8255** the first parameter to callbacks. 8256** 8257** ^The preupdate hook only fires for changes to real database tables; the 8258** preupdate hook is not invoked for changes to [virtual tables] or to 8259** system tables like sqlite_master or sqlite_stat1. 8260** 8261** ^The second parameter to the preupdate callback is a pointer to 8262** the [database connection] that registered the preupdate hook. 8263** ^The third parameter to the preupdate callback is one of the constants 8264** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 8265** kind of update operation that is about to occur. 8266** ^(The fourth parameter to the preupdate callback is the name of the 8267** database within the database connection that is being modified. This 8268** will be "main" for the main database or "temp" for TEMP tables or 8269** the name given after the AS keyword in the [ATTACH] statement for attached 8270** databases.)^ 8271** ^The fifth parameter to the preupdate callback is the name of the 8272** table that is being modified. 8273** 8274** For an UPDATE or DELETE operation on a [rowid table], the sixth 8275** parameter passed to the preupdate callback is the initial [rowid] of the 8276** row being modified or deleted. For an INSERT operation on a rowid table, 8277** or any operation on a WITHOUT ROWID table, the value of the sixth 8278** parameter is undefined. For an INSERT or UPDATE on a rowid table the 8279** seventh parameter is the final rowid value of the row being inserted 8280** or updated. The value of the seventh parameter passed to the callback 8281** function is not defined for operations on WITHOUT ROWID tables, or for 8282** INSERT operations on rowid tables. 8283** 8284** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 8285** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 8286** provide additional information about a preupdate event. These routines 8287** may only be called from within a preupdate callback. Invoking any of 8288** these routines from outside of a preupdate callback or with a 8289** [database connection] pointer that is different from the one supplied 8290** to the preupdate callback results in undefined and probably undesirable 8291** behavior. 8292** 8293** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 8294** in the row that is being inserted, updated, or deleted. 8295** 8296** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 8297** a [protected sqlite3_value] that contains the value of the Nth column of 8298** the table row before it is updated. The N parameter must be between 0 8299** and one less than the number of columns or the behavior will be 8300** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 8301** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 8302** behavior is undefined. The [sqlite3_value] that P points to 8303** will be destroyed when the preupdate callback returns. 8304** 8305** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 8306** a [protected sqlite3_value] that contains the value of the Nth column of 8307** the table row after it is updated. The N parameter must be between 0 8308** and one less than the number of columns or the behavior will be 8309** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 8310** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 8311** behavior is undefined. The [sqlite3_value] that P points to 8312** will be destroyed when the preupdate callback returns. 8313** 8314** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 8315** callback was invoked as a result of a direct insert, update, or delete 8316** operation; or 1 for inserts, updates, or deletes invoked by top-level 8317** triggers; or 2 for changes resulting from triggers called by top-level 8318** triggers; and so forth. 8319** 8320** See also: [sqlite3_update_hook()] 8321*/ 8322#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 8323void *sqlite3_preupdate_hook( 8324 sqlite3 *db, 8325 void(*xPreUpdate)( 8326 void *pCtx, /* Copy of third arg to preupdate_hook() */ 8327 sqlite3 *db, /* Database handle */ 8328 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 8329 char const *zDb, /* Database name */ 8330 char const *zName, /* Table name */ 8331 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 8332 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 8333 ), 8334 void* 8335); 8336int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 8337int sqlite3_preupdate_count(sqlite3 *); 8338int sqlite3_preupdate_depth(sqlite3 *); 8339int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 8340#endif 8341 8342/* 8343** CAPI3REF: Low-level system error code 8344** 8345** ^Attempt to return the underlying operating system error code or error 8346** number that caused the most recent I/O error or failure to open a file. 8347** The return value is OS-dependent. For example, on unix systems, after 8348** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 8349** called to get back the underlying "errno" that caused the problem, such 8350** as ENOSPC, EAUTH, EISDIR, and so forth. 8351*/ 8352int sqlite3_system_errno(sqlite3*); 8353 8354/* 8355** CAPI3REF: Database Snapshot 8356** KEYWORDS: {snapshot} {sqlite3_snapshot} 8357** EXPERIMENTAL 8358** 8359** An instance of the snapshot object records the state of a [WAL mode] 8360** database for some specific point in history. 8361** 8362** In [WAL mode], multiple [database connections] that are open on the 8363** same database file can each be reading a different historical version 8364** of the database file. When a [database connection] begins a read 8365** transaction, that connection sees an unchanging copy of the database 8366** as it existed for the point in time when the transaction first started. 8367** Subsequent changes to the database from other connections are not seen 8368** by the reader until a new read transaction is started. 8369** 8370** The sqlite3_snapshot object records state information about an historical 8371** version of the database file so that it is possible to later open a new read 8372** transaction that sees that historical version of the database rather than 8373** the most recent version. 8374** 8375** The constructor for this object is [sqlite3_snapshot_get()]. The 8376** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer 8377** to an historical snapshot (if possible). The destructor for 8378** sqlite3_snapshot objects is [sqlite3_snapshot_free()]. 8379*/ 8380typedef struct sqlite3_snapshot { 8381 unsigned char hidden[48]; 8382} sqlite3_snapshot; 8383 8384/* 8385** CAPI3REF: Record A Database Snapshot 8386** EXPERIMENTAL 8387** 8388** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 8389** new [sqlite3_snapshot] object that records the current state of 8390** schema S in database connection D. ^On success, the 8391** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 8392** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 8393** If there is not already a read-transaction open on schema S when 8394** this function is called, one is opened automatically. 8395** 8396** The following must be true for this function to succeed. If any of 8397** the following statements are false when sqlite3_snapshot_get() is 8398** called, SQLITE_ERROR is returned. The final value of *P is undefined 8399** in this case. 8400** 8401** <ul> 8402** <li> The database handle must be in [autocommit mode]. 8403** 8404** <li> Schema S of [database connection] D must be a [WAL mode] database. 8405** 8406** <li> There must not be a write transaction open on schema S of database 8407** connection D. 8408** 8409** <li> One or more transactions must have been written to the current wal 8410** file since it was created on disk (by any connection). This means 8411** that a snapshot cannot be taken on a wal mode database with no wal 8412** file immediately after it is first opened. At least one transaction 8413** must be written to it first. 8414** </ul> 8415** 8416** This function may also return SQLITE_NOMEM. If it is called with the 8417** database handle in autocommit mode but fails for some other reason, 8418** whether or not a read transaction is opened on schema S is undefined. 8419** 8420** The [sqlite3_snapshot] object returned from a successful call to 8421** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 8422** to avoid a memory leak. 8423** 8424** The [sqlite3_snapshot_get()] interface is only available when the 8425** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8426*/ 8427SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 8428 sqlite3 *db, 8429 const char *zSchema, 8430 sqlite3_snapshot **ppSnapshot 8431); 8432 8433/* 8434** CAPI3REF: Start a read transaction on an historical snapshot 8435** EXPERIMENTAL 8436** 8437** ^The [sqlite3_snapshot_open(D,S,P)] interface starts a 8438** read transaction for schema S of 8439** [database connection] D such that the read transaction 8440** refers to historical [snapshot] P, rather than the most 8441** recent change to the database. 8442** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success 8443** or an appropriate [error code] if it fails. 8444** 8445** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be 8446** the first operation following the [BEGIN] that takes the schema S 8447** out of [autocommit mode]. 8448** ^In other words, schema S must not currently be in 8449** a transaction for [sqlite3_snapshot_open(D,S,P)] to work, but the 8450** database connection D must be out of [autocommit mode]. 8451** ^A [snapshot] will fail to open if it has been overwritten by a 8452** [checkpoint]. 8453** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 8454** database connection D does not know that the database file for 8455** schema S is in [WAL mode]. A database connection might not know 8456** that the database file is in [WAL mode] if there has been no prior 8457** I/O on that database connection, or if the database entered [WAL mode] 8458** after the most recent I/O on the database connection.)^ 8459** (Hint: Run "[PRAGMA application_id]" against a newly opened 8460** database connection in order to make it ready to use snapshots.) 8461** 8462** The [sqlite3_snapshot_open()] interface is only available when the 8463** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8464*/ 8465SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 8466 sqlite3 *db, 8467 const char *zSchema, 8468 sqlite3_snapshot *pSnapshot 8469); 8470 8471/* 8472** CAPI3REF: Destroy a snapshot 8473** EXPERIMENTAL 8474** 8475** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 8476** The application must eventually free every [sqlite3_snapshot] object 8477** using this routine to avoid a memory leak. 8478** 8479** The [sqlite3_snapshot_free()] interface is only available when the 8480** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8481*/ 8482SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 8483 8484/* 8485** CAPI3REF: Compare the ages of two snapshot handles. 8486** EXPERIMENTAL 8487** 8488** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 8489** of two valid snapshot handles. 8490** 8491** If the two snapshot handles are not associated with the same database 8492** file, the result of the comparison is undefined. 8493** 8494** Additionally, the result of the comparison is only valid if both of the 8495** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 8496** last time the wal file was deleted. The wal file is deleted when the 8497** database is changed back to rollback mode or when the number of database 8498** clients drops to zero. If either snapshot handle was obtained before the 8499** wal file was last deleted, the value returned by this function 8500** is undefined. 8501** 8502** Otherwise, this API returns a negative value if P1 refers to an older 8503** snapshot than P2, zero if the two handles refer to the same database 8504** snapshot, and a positive value if P1 is a newer snapshot than P2. 8505*/ 8506SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 8507 sqlite3_snapshot *p1, 8508 sqlite3_snapshot *p2 8509); 8510 8511/* 8512** CAPI3REF: Recover snapshots from a wal file 8513** EXPERIMENTAL 8514** 8515** If all connections disconnect from a database file but do not perform 8516** a checkpoint, the existing wal file is opened along with the database 8517** file the next time the database is opened. At this point it is only 8518** possible to successfully call sqlite3_snapshot_open() to open the most 8519** recent snapshot of the database (the one at the head of the wal file), 8520** even though the wal file may contain other valid snapshots for which 8521** clients have sqlite3_snapshot handles. 8522** 8523** This function attempts to scan the wal file associated with database zDb 8524** of database handle db and make all valid snapshots available to 8525** sqlite3_snapshot_open(). It is an error if there is already a read 8526** transaction open on the database, or if the database is not a wal mode 8527** database. 8528** 8529** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 8530*/ 8531SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 8532 8533/* 8534** Undo the hack that converts floating point types to integer for 8535** builds on processors without floating point support. 8536*/ 8537#ifdef SQLITE_OMIT_FLOATING_POINT 8538# undef double 8539#endif 8540 8541#ifdef __cplusplus 8542} /* End of the 'extern "C"' block */ 8543#endif 8544#endif /* SQLITE3_H */ 8545