1/* 2** 2001-09-15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are supposed to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef SQLITE3_H 34#define SQLITE3_H 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Provide the ability to override linkage features of the interface. 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51#ifndef SQLITE_API 52# define SQLITE_API 53#endif 54#ifndef SQLITE_CDECL 55# define SQLITE_CDECL 56#endif 57#ifndef SQLITE_APICALL 58# define SQLITE_APICALL 59#endif 60#ifndef SQLITE_STDCALL 61# define SQLITE_STDCALL SQLITE_APICALL 62#endif 63#ifndef SQLITE_CALLBACK 64# define SQLITE_CALLBACK 65#endif 66#ifndef SQLITE_SYSAPI 67# define SQLITE_SYSAPI 68#endif 69 70/* 71** These no-op macros are used in front of interfaces to mark those 72** interfaces as either deprecated or experimental. New applications 73** should not use deprecated interfaces - they are supported for backwards 74** compatibility only. Application writers should be aware that 75** experimental interfaces are subject to change in point releases. 76** 77** These macros used to resolve to various kinds of compiler magic that 78** would generate warning messages when they were used. But that 79** compiler magic ended up generating such a flurry of bug reports 80** that we have taken it all out and gone back to using simple 81** noop macros. 82*/ 83#define SQLITE_DEPRECATED 84#define SQLITE_EXPERIMENTAL 85 86/* 87** Ensure these symbols were not defined by some previous header file. 88*/ 89#ifdef SQLITE_VERSION 90# undef SQLITE_VERSION 91#endif 92#ifdef SQLITE_VERSION_NUMBER 93# undef SQLITE_VERSION_NUMBER 94#endif 95 96/* 97** CAPI3REF: Compile-Time Library Version Numbers 98** 99** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 100** evaluates to a string literal that is the SQLite version in the 101** format "X.Y.Z" where X is the major version number (always 3 for 102** SQLite3) and Y is the minor version number and Z is the release number.)^ 103** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 104** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 105** numbers used in [SQLITE_VERSION].)^ 106** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 107** be larger than the release from which it is derived. Either Y will 108** be held constant and Z will be incremented or else Y will be incremented 109** and Z will be reset to zero. 110** 111** Since [version 3.6.18] ([dateof:3.6.18]), 112** SQLite source code has been stored in the 113** <a href="http://www.fossil-scm.org/">Fossil configuration management 114** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 115** a string which identifies a particular check-in of SQLite 116** within its configuration management system. ^The SQLITE_SOURCE_ID 117** string contains the date and time of the check-in (UTC) and a SHA1 118** or SHA3-256 hash of the entire source tree. 119** 120** See also: [sqlite3_libversion()], 121** [sqlite3_libversion_number()], [sqlite3_sourceid()], 122** [sqlite_version()] and [sqlite_source_id()]. 123*/ 124#define SQLITE_VERSION "--VERS--" 125#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 126#define SQLITE_SOURCE_ID "--SOURCE-ID--" 127 128/* 129** CAPI3REF: Run-Time Library Version Numbers 130** KEYWORDS: sqlite3_version sqlite3_sourceid 131** 132** These interfaces provide the same information as the [SQLITE_VERSION], 133** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 134** but are associated with the library instead of the header file. ^(Cautious 135** programmers might include assert() statements in their application to 136** verify that values returned by these interfaces match the macros in 137** the header, and thus ensure that the application is 138** compiled with matching library and header files. 139** 140** <blockquote><pre> 141** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 142** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 143** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 144** </pre></blockquote>)^ 145** 146** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 147** macro. ^The sqlite3_libversion() function returns a pointer to the 148** to the sqlite3_version[] string constant. The sqlite3_libversion() 149** function is provided for use in DLLs since DLL users usually do not have 150** direct access to string constants within the DLL. ^The 151** sqlite3_libversion_number() function returns an integer equal to 152** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 153** a pointer to a string constant whose value is the same as the 154** [SQLITE_SOURCE_ID] C preprocessor macro. 155** 156** See also: [sqlite_version()] and [sqlite_source_id()]. 157*/ 158SQLITE_EXTERN const char sqlite3_version[]; 159const char *sqlite3_libversion(void); 160const char *sqlite3_sourceid(void); 161int sqlite3_libversion_number(void); 162 163/* 164** CAPI3REF: Run-Time Library Compilation Options Diagnostics 165** 166** ^The sqlite3_compileoption_used() function returns 0 or 1 167** indicating whether the specified option was defined at 168** compile time. ^The SQLITE_ prefix may be omitted from the 169** option name passed to sqlite3_compileoption_used(). 170** 171** ^The sqlite3_compileoption_get() function allows iterating 172** over the list of options that were defined at compile time by 173** returning the N-th compile time option string. ^If N is out of range, 174** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 175** prefix is omitted from any strings returned by 176** sqlite3_compileoption_get(). 177** 178** ^Support for the diagnostic functions sqlite3_compileoption_used() 179** and sqlite3_compileoption_get() may be omitted by specifying the 180** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 181** 182** See also: SQL functions [sqlite_compileoption_used()] and 183** [sqlite_compileoption_get()] and the [compile_options pragma]. 184*/ 185#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 186int sqlite3_compileoption_used(const char *zOptName); 187const char *sqlite3_compileoption_get(int N); 188#endif 189 190/* 191** CAPI3REF: Test To See If The Library Is Threadsafe 192** 193** ^The sqlite3_threadsafe() function returns zero if and only if 194** SQLite was compiled with mutexing code omitted due to the 195** [SQLITE_THREADSAFE] compile-time option being set to 0. 196** 197** SQLite can be compiled with or without mutexes. When 198** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 199** are enabled and SQLite is threadsafe. When the 200** [SQLITE_THREADSAFE] macro is 0, 201** the mutexes are omitted. Without the mutexes, it is not safe 202** to use SQLite concurrently from more than one thread. 203** 204** Enabling mutexes incurs a measurable performance penalty. 205** So if speed is of utmost importance, it makes sense to disable 206** the mutexes. But for maximum safety, mutexes should be enabled. 207** ^The default behavior is for mutexes to be enabled. 208** 209** This interface can be used by an application to make sure that the 210** version of SQLite that it is linking against was compiled with 211** the desired setting of the [SQLITE_THREADSAFE] macro. 212** 213** This interface only reports on the compile-time mutex setting 214** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 215** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 216** can be fully or partially disabled using a call to [sqlite3_config()] 217** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 218** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the 219** sqlite3_threadsafe() function shows only the compile-time setting of 220** thread safety, not any run-time changes to that setting made by 221** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 222** is unchanged by calls to sqlite3_config().)^ 223** 224** See the [threading mode] documentation for additional information. 225*/ 226int sqlite3_threadsafe(void); 227 228/* 229** CAPI3REF: Database Connection Handle 230** KEYWORDS: {database connection} {database connections} 231** 232** Each open SQLite database is represented by a pointer to an instance of 233** the opaque structure named "sqlite3". It is useful to think of an sqlite3 234** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 235** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 236** and [sqlite3_close_v2()] are its destructors. There are many other 237** interfaces (such as 238** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 239** [sqlite3_busy_timeout()] to name but three) that are methods on an 240** sqlite3 object. 241*/ 242typedef struct sqlite3 sqlite3; 243 244/* 245** CAPI3REF: 64-Bit Integer Types 246** KEYWORDS: sqlite_int64 sqlite_uint64 247** 248** Because there is no cross-platform way to specify 64-bit integer types 249** SQLite includes typedefs for 64-bit signed and unsigned integers. 250** 251** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 252** The sqlite_int64 and sqlite_uint64 types are supported for backwards 253** compatibility only. 254** 255** ^The sqlite3_int64 and sqlite_int64 types can store integer values 256** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 257** sqlite3_uint64 and sqlite_uint64 types can store integer values 258** between 0 and +18446744073709551615 inclusive. 259*/ 260#ifdef SQLITE_INT64_TYPE 261 typedef SQLITE_INT64_TYPE sqlite_int64; 262# ifdef SQLITE_UINT64_TYPE 263 typedef SQLITE_UINT64_TYPE sqlite_uint64; 264# else 265 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 266# endif 267#elif defined(_MSC_VER) || defined(__BORLANDC__) 268 typedef __int64 sqlite_int64; 269 typedef unsigned __int64 sqlite_uint64; 270#else 271 typedef long long int sqlite_int64; 272 typedef unsigned long long int sqlite_uint64; 273#endif 274typedef sqlite_int64 sqlite3_int64; 275typedef sqlite_uint64 sqlite3_uint64; 276 277/* 278** If compiling for a processor that lacks floating point support, 279** substitute integer for floating-point. 280*/ 281#ifdef SQLITE_OMIT_FLOATING_POINT 282# define double sqlite3_int64 283#endif 284 285/* 286** CAPI3REF: Closing A Database Connection 287** DESTRUCTOR: sqlite3 288** 289** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 290** for the [sqlite3] object. 291** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 292** the [sqlite3] object is successfully destroyed and all associated 293** resources are deallocated. 294** 295** ^If the database connection is associated with unfinalized prepared 296** statements or unfinished sqlite3_backup objects then sqlite3_close() 297** will leave the database connection open and return [SQLITE_BUSY]. 298** ^If sqlite3_close_v2() is called with unfinalized prepared statements 299** and/or unfinished sqlite3_backups, then the database connection becomes 300** an unusable "zombie" which will automatically be deallocated when the 301** last prepared statement is finalized or the last sqlite3_backup is 302** finished. The sqlite3_close_v2() interface is intended for use with 303** host languages that are garbage collected, and where the order in which 304** destructors are called is arbitrary. 305** 306** Applications should [sqlite3_finalize | finalize] all [prepared statements], 307** [sqlite3_blob_close | close] all [BLOB handles], and 308** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 309** with the [sqlite3] object prior to attempting to close the object. ^If 310** sqlite3_close_v2() is called on a [database connection] that still has 311** outstanding [prepared statements], [BLOB handles], and/or 312** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation 313** of resources is deferred until all [prepared statements], [BLOB handles], 314** and [sqlite3_backup] objects are also destroyed. 315** 316** ^If an [sqlite3] object is destroyed while a transaction is open, 317** the transaction is automatically rolled back. 318** 319** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 320** must be either a NULL 321** pointer or an [sqlite3] object pointer obtained 322** from [sqlite3_open()], [sqlite3_open16()], or 323** [sqlite3_open_v2()], and not previously closed. 324** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 325** argument is a harmless no-op. 326*/ 327int sqlite3_close(sqlite3*); 328int sqlite3_close_v2(sqlite3*); 329 330/* 331** The type for a callback function. 332** This is legacy and deprecated. It is included for historical 333** compatibility and is not documented. 334*/ 335typedef int (*sqlite3_callback)(void*,int,char**, char**); 336 337/* 338** CAPI3REF: One-Step Query Execution Interface 339** METHOD: sqlite3 340** 341** The sqlite3_exec() interface is a convenience wrapper around 342** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 343** that allows an application to run multiple statements of SQL 344** without having to use a lot of C code. 345** 346** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 347** semicolon-separate SQL statements passed into its 2nd argument, 348** in the context of the [database connection] passed in as its 1st 349** argument. ^If the callback function of the 3rd argument to 350** sqlite3_exec() is not NULL, then it is invoked for each result row 351** coming out of the evaluated SQL statements. ^The 4th argument to 352** sqlite3_exec() is relayed through to the 1st argument of each 353** callback invocation. ^If the callback pointer to sqlite3_exec() 354** is NULL, then no callback is ever invoked and result rows are 355** ignored. 356** 357** ^If an error occurs while evaluating the SQL statements passed into 358** sqlite3_exec(), then execution of the current statement stops and 359** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 360** is not NULL then any error message is written into memory obtained 361** from [sqlite3_malloc()] and passed back through the 5th parameter. 362** To avoid memory leaks, the application should invoke [sqlite3_free()] 363** on error message strings returned through the 5th parameter of 364** sqlite3_exec() after the error message string is no longer needed. 365** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 366** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 367** NULL before returning. 368** 369** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 370** routine returns SQLITE_ABORT without invoking the callback again and 371** without running any subsequent SQL statements. 372** 373** ^The 2nd argument to the sqlite3_exec() callback function is the 374** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 375** callback is an array of pointers to strings obtained as if from 376** [sqlite3_column_text()], one for each column. ^If an element of a 377** result row is NULL then the corresponding string pointer for the 378** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 379** sqlite3_exec() callback is an array of pointers to strings where each 380** entry represents the name of corresponding result column as obtained 381** from [sqlite3_column_name()]. 382** 383** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 384** to an empty string, or a pointer that contains only whitespace and/or 385** SQL comments, then no SQL statements are evaluated and the database 386** is not changed. 387** 388** Restrictions: 389** 390** <ul> 391** <li> The application must ensure that the 1st parameter to sqlite3_exec() 392** is a valid and open [database connection]. 393** <li> The application must not close the [database connection] specified by 394** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 395** <li> The application must not modify the SQL statement text passed into 396** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 397** </ul> 398*/ 399int sqlite3_exec( 400 sqlite3*, /* An open database */ 401 const char *sql, /* SQL to be evaluated */ 402 int (*callback)(void*,int,char**,char**), /* Callback function */ 403 void *, /* 1st argument to callback */ 404 char **errmsg /* Error msg written here */ 405); 406 407/* 408** CAPI3REF: Result Codes 409** KEYWORDS: {result code definitions} 410** 411** Many SQLite functions return an integer result code from the set shown 412** here in order to indicate success or failure. 413** 414** New error codes may be added in future versions of SQLite. 415** 416** See also: [extended result code definitions] 417*/ 418#define SQLITE_OK 0 /* Successful result */ 419/* beginning-of-error-codes */ 420#define SQLITE_ERROR 1 /* Generic error */ 421#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 422#define SQLITE_PERM 3 /* Access permission denied */ 423#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 424#define SQLITE_BUSY 5 /* The database file is locked */ 425#define SQLITE_LOCKED 6 /* A table in the database is locked */ 426#define SQLITE_NOMEM 7 /* A malloc() failed */ 427#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 428#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 429#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 430#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 431#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 432#define SQLITE_FULL 13 /* Insertion failed because database is full */ 433#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 434#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 435#define SQLITE_EMPTY 16 /* Not used */ 436#define SQLITE_SCHEMA 17 /* The database schema changed */ 437#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 438#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 439#define SQLITE_MISMATCH 20 /* Data type mismatch */ 440#define SQLITE_MISUSE 21 /* Library used incorrectly */ 441#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 442#define SQLITE_AUTH 23 /* Authorization denied */ 443#define SQLITE_FORMAT 24 /* Not used */ 444#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 445#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 446#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 447#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 448#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 449#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 450/* end-of-error-codes */ 451 452/* 453** CAPI3REF: Extended Result Codes 454** KEYWORDS: {extended result code definitions} 455** 456** In its default configuration, SQLite API routines return one of 30 integer 457** [result codes]. However, experience has shown that many of 458** these result codes are too coarse-grained. They do not provide as 459** much information about problems as programmers might like. In an effort to 460** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8] 461** and later) include 462** support for additional result codes that provide more detailed information 463** about errors. These [extended result codes] are enabled or disabled 464** on a per database connection basis using the 465** [sqlite3_extended_result_codes()] API. Or, the extended code for 466** the most recent error can be obtained using 467** [sqlite3_extended_errcode()]. 468*/ 469#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 470#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 471#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 472#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 473#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 474#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 475#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 476#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 477#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 478#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 479#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 480#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 481#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 482#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 483#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 484#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 485#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 486#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 487#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 488#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 489#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 490#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 491#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 492#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 493#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 494#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 495#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8)) 496#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8)) 497#define SQLITE_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_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2695** and [sqlite3_prepare16_v3()]. ^At various 2696** points during the compilation process, as logic is being created 2697** to perform various actions, the authorizer callback is invoked to 2698** see if those actions are allowed. ^The authorizer callback should 2699** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2700** specific action but allow the SQL statement to continue to be 2701** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2702** rejected with an error. ^If the authorizer callback returns 2703** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2704** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2705** the authorizer will fail with an error message. 2706** 2707** When the callback returns [SQLITE_OK], that means the operation 2708** requested is ok. ^When the callback returns [SQLITE_DENY], the 2709** [sqlite3_prepare_v2()] or equivalent call that triggered the 2710** authorizer will fail with an error message explaining that 2711** access is denied. 2712** 2713** ^The first parameter to the authorizer callback is a copy of the third 2714** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2715** to the callback is an integer [SQLITE_COPY | action code] that specifies 2716** the particular action to be authorized. ^The third through sixth parameters 2717** to the callback are either NULL pointers or zero-terminated strings 2718** that contain additional details about the action to be authorized. 2719** Applications must always be prepared to encounter a NULL pointer in any 2720** of the third through the sixth parameters of the authorization callback. 2721** 2722** ^If the action code is [SQLITE_READ] 2723** and the callback returns [SQLITE_IGNORE] then the 2724** [prepared statement] statement is constructed to substitute 2725** a NULL value in place of the table column that would have 2726** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2727** return can be used to deny an untrusted user access to individual 2728** columns of a table. 2729** ^When a table is referenced by a [SELECT] but no column values are 2730** extracted from that table (for example in a query like 2731** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2732** is invoked once for that table with a column name that is an empty string. 2733** ^If the action code is [SQLITE_DELETE] and the callback returns 2734** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2735** [truncate optimization] is disabled and all rows are deleted individually. 2736** 2737** An authorizer is used when [sqlite3_prepare | preparing] 2738** SQL statements from an untrusted source, to ensure that the SQL statements 2739** do not try to access data they are not allowed to see, or that they do not 2740** try to execute malicious statements that damage the database. For 2741** example, an application may allow a user to enter arbitrary 2742** SQL queries for evaluation by a database. But the application does 2743** not want the user to be able to make arbitrary changes to the 2744** database. An authorizer could then be put in place while the 2745** user-entered SQL is being [sqlite3_prepare | prepared] that 2746** disallows everything except [SELECT] statements. 2747** 2748** Applications that need to process SQL from untrusted sources 2749** might also consider lowering resource limits using [sqlite3_limit()] 2750** and limiting database size using the [max_page_count] [PRAGMA] 2751** in addition to using an authorizer. 2752** 2753** ^(Only a single authorizer can be in place on a database connection 2754** at a time. Each call to sqlite3_set_authorizer overrides the 2755** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2756** The authorizer is disabled by default. 2757** 2758** The authorizer callback must not do anything that will modify 2759** the database connection that invoked the authorizer callback. 2760** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2761** database connections for the meaning of "modify" in this paragraph. 2762** 2763** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2764** statement might be re-prepared during [sqlite3_step()] due to a 2765** schema change. Hence, the application should ensure that the 2766** correct authorizer callback remains in place during the [sqlite3_step()]. 2767** 2768** ^Note that the authorizer callback is invoked only during 2769** [sqlite3_prepare()] or its variants. Authorization is not 2770** performed during statement evaluation in [sqlite3_step()], unless 2771** as stated in the previous paragraph, sqlite3_step() invokes 2772** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2773*/ 2774int sqlite3_set_authorizer( 2775 sqlite3*, 2776 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2777 void *pUserData 2778); 2779 2780/* 2781** CAPI3REF: Authorizer Return Codes 2782** 2783** The [sqlite3_set_authorizer | authorizer callback function] must 2784** return either [SQLITE_OK] or one of these two constants in order 2785** to signal SQLite whether or not the action is permitted. See the 2786** [sqlite3_set_authorizer | authorizer documentation] for additional 2787** information. 2788** 2789** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2790** returned from the [sqlite3_vtab_on_conflict()] interface. 2791*/ 2792#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2793#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2794 2795/* 2796** CAPI3REF: Authorizer Action Codes 2797** 2798** The [sqlite3_set_authorizer()] interface registers a callback function 2799** that is invoked to authorize certain SQL statement actions. The 2800** second parameter to the callback is an integer code that specifies 2801** what action is being authorized. These are the integer action codes that 2802** the authorizer callback may be passed. 2803** 2804** These action code values signify what kind of operation is to be 2805** authorized. The 3rd and 4th parameters to the authorization 2806** callback function will be parameters or NULL depending on which of these 2807** codes is used as the second parameter. ^(The 5th parameter to the 2808** authorizer callback is the name of the database ("main", "temp", 2809** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2810** is the name of the inner-most trigger or view that is responsible for 2811** the access attempt or NULL if this access attempt is directly from 2812** top-level SQL code. 2813*/ 2814/******************************************* 3rd ************ 4th ***********/ 2815#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2816#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2817#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2818#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2819#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2820#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2821#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2822#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2823#define SQLITE_DELETE 9 /* Table Name NULL */ 2824#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2825#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2826#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2827#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2828#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2829#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2830#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2831#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2832#define SQLITE_INSERT 18 /* Table Name NULL */ 2833#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2834#define SQLITE_READ 20 /* Table Name Column Name */ 2835#define SQLITE_SELECT 21 /* NULL NULL */ 2836#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2837#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2838#define SQLITE_ATTACH 24 /* Filename NULL */ 2839#define SQLITE_DETACH 25 /* Database Name NULL */ 2840#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2841#define SQLITE_REINDEX 27 /* Index Name NULL */ 2842#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2843#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2844#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2845#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2846#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2847#define SQLITE_COPY 0 /* No longer used */ 2848#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2849 2850/* 2851** CAPI3REF: Tracing And Profiling Functions 2852** METHOD: sqlite3 2853** 2854** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 2855** instead of the routines described here. 2856** 2857** These routines register callback functions that can be used for 2858** tracing and profiling the execution of SQL statements. 2859** 2860** ^The callback function registered by sqlite3_trace() is invoked at 2861** various times when an SQL statement is being run by [sqlite3_step()]. 2862** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2863** SQL statement text as the statement first begins executing. 2864** ^(Additional sqlite3_trace() callbacks might occur 2865** as each triggered subprogram is entered. The callbacks for triggers 2866** contain a UTF-8 SQL comment that identifies the trigger.)^ 2867** 2868** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2869** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2870** 2871** ^The callback function registered by sqlite3_profile() is invoked 2872** as each SQL statement finishes. ^The profile callback contains 2873** the original statement text and an estimate of wall-clock time 2874** of how long that statement took to run. ^The profile callback 2875** time is in units of nanoseconds, however the current implementation 2876** is only capable of millisecond resolution so the six least significant 2877** digits in the time are meaningless. Future versions of SQLite 2878** might provide greater resolution on the profiler callback. The 2879** sqlite3_profile() function is considered experimental and is 2880** subject to change in future versions of SQLite. 2881*/ 2882SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 2883 void(*xTrace)(void*,const char*), void*); 2884SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 2885 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2886 2887/* 2888** CAPI3REF: SQL Trace Event Codes 2889** KEYWORDS: SQLITE_TRACE 2890** 2891** These constants identify classes of events that can be monitored 2892** using the [sqlite3_trace_v2()] tracing logic. The third argument 2893** to [sqlite3_trace_v2()] is an OR-ed combination of one or more of 2894** the following constants. ^The first argument to the trace callback 2895** is one of the following constants. 2896** 2897** New tracing constants may be added in future releases. 2898** 2899** ^A trace callback has four arguments: xCallback(T,C,P,X). 2900** ^The T argument is one of the integer type codes above. 2901** ^The C argument is a copy of the context pointer passed in as the 2902** fourth argument to [sqlite3_trace_v2()]. 2903** The P and X arguments are pointers whose meanings depend on T. 2904** 2905** <dl> 2906** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 2907** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 2908** first begins running and possibly at other times during the 2909** execution of the prepared statement, such as at the start of each 2910** trigger subprogram. ^The P argument is a pointer to the 2911** [prepared statement]. ^The X argument is a pointer to a string which 2912** is the unexpanded SQL text of the prepared statement or an SQL comment 2913** that indicates the invocation of a trigger. ^The callback can compute 2914** the same text that would have been returned by the legacy [sqlite3_trace()] 2915** interface by using the X argument when X begins with "--" and invoking 2916** [sqlite3_expanded_sql(P)] otherwise. 2917** 2918** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 2919** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 2920** information as is provided by the [sqlite3_profile()] callback. 2921** ^The P argument is a pointer to the [prepared statement] and the 2922** X argument points to a 64-bit integer which is the estimated of 2923** the number of nanosecond that the prepared statement took to run. 2924** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 2925** 2926** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 2927** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 2928** statement generates a single row of result. 2929** ^The P argument is a pointer to the [prepared statement] and the 2930** X argument is unused. 2931** 2932** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 2933** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 2934** connection closes. 2935** ^The P argument is a pointer to the [database connection] object 2936** and the X argument is unused. 2937** </dl> 2938*/ 2939#define SQLITE_TRACE_STMT 0x01 2940#define SQLITE_TRACE_PROFILE 0x02 2941#define SQLITE_TRACE_ROW 0x04 2942#define SQLITE_TRACE_CLOSE 0x08 2943 2944/* 2945** CAPI3REF: SQL Trace Hook 2946** METHOD: sqlite3 2947** 2948** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 2949** function X against [database connection] D, using property mask M 2950** and context pointer P. ^If the X callback is 2951** NULL or if the M mask is zero, then tracing is disabled. The 2952** M argument should be the bitwise OR-ed combination of 2953** zero or more [SQLITE_TRACE] constants. 2954** 2955** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 2956** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 2957** 2958** ^The X callback is invoked whenever any of the events identified by 2959** mask M occur. ^The integer return value from the callback is currently 2960** ignored, though this may change in future releases. Callback 2961** implementations should return zero to ensure future compatibility. 2962** 2963** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 2964** ^The T argument is one of the [SQLITE_TRACE] 2965** constants to indicate why the callback was invoked. 2966** ^The C argument is a copy of the context pointer. 2967** The P and X arguments are pointers whose meanings depend on T. 2968** 2969** The sqlite3_trace_v2() interface is intended to replace the legacy 2970** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 2971** are deprecated. 2972*/ 2973int sqlite3_trace_v2( 2974 sqlite3*, 2975 unsigned uMask, 2976 int(*xCallback)(unsigned,void*,void*,void*), 2977 void *pCtx 2978); 2979 2980/* 2981** CAPI3REF: Query Progress Callbacks 2982** METHOD: sqlite3 2983** 2984** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2985** function X to be invoked periodically during long running calls to 2986** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2987** database connection D. An example use for this 2988** interface is to keep a GUI updated during a large query. 2989** 2990** ^The parameter P is passed through as the only parameter to the 2991** callback function X. ^The parameter N is the approximate number of 2992** [virtual machine instructions] that are evaluated between successive 2993** invocations of the callback X. ^If N is less than one then the progress 2994** handler is disabled. 2995** 2996** ^Only a single progress handler may be defined at one time per 2997** [database connection]; setting a new progress handler cancels the 2998** old one. ^Setting parameter X to NULL disables the progress handler. 2999** ^The progress handler is also disabled by setting N to a value less 3000** than 1. 3001** 3002** ^If the progress callback returns non-zero, the operation is 3003** interrupted. This feature can be used to implement a 3004** "Cancel" button on a GUI progress dialog box. 3005** 3006** The progress handler callback must not do anything that will modify 3007** the database connection that invoked the progress handler. 3008** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3009** database connections for the meaning of "modify" in this paragraph. 3010** 3011*/ 3012void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3013 3014/* 3015** CAPI3REF: Opening A New Database Connection 3016** CONSTRUCTOR: sqlite3 3017** 3018** ^These routines open an SQLite database file as specified by the 3019** filename argument. ^The filename argument is interpreted as UTF-8 for 3020** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3021** order for sqlite3_open16(). ^(A [database connection] handle is usually 3022** returned in *ppDb, even if an error occurs. The only exception is that 3023** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3024** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3025** object.)^ ^(If the database is opened (and/or created) successfully, then 3026** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3027** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3028** an English language description of the error following a failure of any 3029** of the sqlite3_open() routines. 3030** 3031** ^The default encoding will be UTF-8 for databases created using 3032** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3033** created using sqlite3_open16() will be UTF-16 in the native byte order. 3034** 3035** Whether or not an error occurs when it is opened, resources 3036** associated with the [database connection] handle should be released by 3037** passing it to [sqlite3_close()] when it is no longer required. 3038** 3039** The sqlite3_open_v2() interface works like sqlite3_open() 3040** except that it accepts two additional parameters for additional control 3041** over the new database connection. ^(The flags parameter to 3042** sqlite3_open_v2() can take one of 3043** the following three values, optionally combined with the 3044** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 3045** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 3046** 3047** <dl> 3048** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3049** <dd>The database is opened in read-only mode. If the database does not 3050** already exist, an error is returned.</dd>)^ 3051** 3052** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3053** <dd>The database is opened for reading and writing if possible, or reading 3054** only if the file is write protected by the operating system. In either 3055** case the database must already exist, otherwise an error is returned.</dd>)^ 3056** 3057** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3058** <dd>The database is opened for reading and writing, and is created if 3059** it does not already exist. This is the behavior that is always used for 3060** sqlite3_open() and sqlite3_open16().</dd>)^ 3061** </dl> 3062** 3063** If the 3rd parameter to sqlite3_open_v2() is not one of the 3064** combinations shown above optionally combined with other 3065** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3066** then the behavior is undefined. 3067** 3068** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 3069** opens in the multi-thread [threading mode] as long as the single-thread 3070** mode has not been set at compile-time or start-time. ^If the 3071** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 3072** in the serialized [threading mode] unless single-thread was 3073** previously selected at compile-time or start-time. 3074** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 3075** eligible to use [shared cache mode], regardless of whether or not shared 3076** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 3077** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 3078** participate in [shared cache mode] even if it is enabled. 3079** 3080** ^The fourth parameter to sqlite3_open_v2() is the name of the 3081** [sqlite3_vfs] object that defines the operating system interface that 3082** the new database connection should use. ^If the fourth parameter is 3083** a NULL pointer then the default [sqlite3_vfs] object is used. 3084** 3085** ^If the filename is ":memory:", then a private, temporary in-memory database 3086** is created for the connection. ^This in-memory database will vanish when 3087** the database connection is closed. Future versions of SQLite might 3088** make use of additional special filenames that begin with the ":" character. 3089** It is recommended that when a database filename actually does begin with 3090** a ":" character you should prefix the filename with a pathname such as 3091** "./" to avoid ambiguity. 3092** 3093** ^If the filename is an empty string, then a private, temporary 3094** on-disk database will be created. ^This private database will be 3095** automatically deleted as soon as the database connection is closed. 3096** 3097** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3098** 3099** ^If [URI filename] interpretation is enabled, and the filename argument 3100** begins with "file:", then the filename is interpreted as a URI. ^URI 3101** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3102** set in the fourth argument to sqlite3_open_v2(), or if it has 3103** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3104** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3105** As of SQLite version 3.7.7, URI filename interpretation is turned off 3106** by default, but future releases of SQLite might enable URI filename 3107** interpretation by default. See "[URI filenames]" for additional 3108** information. 3109** 3110** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3111** authority, then it must be either an empty string or the string 3112** "localhost". ^If the authority is not an empty string or "localhost", an 3113** error is returned to the caller. ^The fragment component of a URI, if 3114** present, is ignored. 3115** 3116** ^SQLite uses the path component of the URI as the name of the disk file 3117** which contains the database. ^If the path begins with a '/' character, 3118** then it is interpreted as an absolute path. ^If the path does not begin 3119** with a '/' (meaning that the authority section is omitted from the URI) 3120** then the path is interpreted as a relative path. 3121** ^(On windows, the first component of an absolute path 3122** is a drive specification (e.g. "C:").)^ 3123** 3124** [[core URI query parameters]] 3125** The query component of a URI may contain parameters that are interpreted 3126** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3127** SQLite and its built-in [VFSes] interpret the 3128** following query parameters: 3129** 3130** <ul> 3131** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3132** a VFS object that provides the operating system interface that should 3133** be used to access the database file on disk. ^If this option is set to 3134** an empty string the default VFS object is used. ^Specifying an unknown 3135** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3136** present, then the VFS specified by the option takes precedence over 3137** the value passed as the fourth parameter to sqlite3_open_v2(). 3138** 3139** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3140** "rwc", or "memory". Attempting to set it to any other value is 3141** an error)^. 3142** ^If "ro" is specified, then the database is opened for read-only 3143** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3144** third argument to sqlite3_open_v2(). ^If the mode option is set to 3145** "rw", then the database is opened for read-write (but not create) 3146** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3147** been set. ^Value "rwc" is equivalent to setting both 3148** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3149** set to "memory" then a pure [in-memory database] that never reads 3150** or writes from disk is used. ^It is an error to specify a value for 3151** the mode parameter that is less restrictive than that specified by 3152** the flags passed in the third parameter to sqlite3_open_v2(). 3153** 3154** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3155** "private". ^Setting it to "shared" is equivalent to setting the 3156** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3157** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3158** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3159** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3160** a URI filename, its value overrides any behavior requested by setting 3161** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3162** 3163** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3164** [powersafe overwrite] property does or does not apply to the 3165** storage media on which the database file resides. 3166** 3167** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3168** which if set disables file locking in rollback journal modes. This 3169** is useful for accessing a database on a filesystem that does not 3170** support locking. Caution: Database corruption might result if two 3171** or more processes write to the same database and any one of those 3172** processes uses nolock=1. 3173** 3174** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3175** parameter that indicates that the database file is stored on 3176** read-only media. ^When immutable is set, SQLite assumes that the 3177** database file cannot be changed, even by a process with higher 3178** privilege, and so the database is opened read-only and all locking 3179** and change detection is disabled. Caution: Setting the immutable 3180** property on a database file that does in fact change can result 3181** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3182** See also: [SQLITE_IOCAP_IMMUTABLE]. 3183** 3184** </ul> 3185** 3186** ^Specifying an unknown parameter in the query component of a URI is not an 3187** error. Future versions of SQLite might understand additional query 3188** parameters. See "[query parameters with special meaning to SQLite]" for 3189** additional information. 3190** 3191** [[URI filename examples]] <h3>URI filename examples</h3> 3192** 3193** <table border="1" align=center cellpadding=5> 3194** <tr><th> URI filenames <th> Results 3195** <tr><td> file:data.db <td> 3196** Open the file "data.db" in the current directory. 3197** <tr><td> file:/home/fred/data.db<br> 3198** file:///home/fred/data.db <br> 3199** file://localhost/home/fred/data.db <br> <td> 3200** Open the database file "/home/fred/data.db". 3201** <tr><td> file://darkstar/home/fred/data.db <td> 3202** An error. "darkstar" is not a recognized authority. 3203** <tr><td style="white-space:nowrap"> 3204** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3205** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3206** C:. Note that the %20 escaping in this example is not strictly 3207** necessary - space characters can be used literally 3208** in URI filenames. 3209** <tr><td> file:data.db?mode=ro&cache=private <td> 3210** Open file "data.db" in the current directory for read-only access. 3211** Regardless of whether or not shared-cache mode is enabled by 3212** default, use a private cache. 3213** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3214** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3215** that uses dot-files in place of posix advisory locking. 3216** <tr><td> file:data.db?mode=readonly <td> 3217** An error. "readonly" is not a valid option for the "mode" parameter. 3218** </table> 3219** 3220** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3221** query components of a URI. A hexadecimal escape sequence consists of a 3222** percent sign - "%" - followed by exactly two hexadecimal digits 3223** specifying an octet value. ^Before the path or query components of a 3224** URI filename are interpreted, they are encoded using UTF-8 and all 3225** hexadecimal escape sequences replaced by a single byte containing the 3226** corresponding octet. If this process generates an invalid UTF-8 encoding, 3227** the results are undefined. 3228** 3229** <b>Note to Windows users:</b> The encoding used for the filename argument 3230** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3231** codepage is currently defined. Filenames containing international 3232** characters must be converted to UTF-8 prior to passing them into 3233** sqlite3_open() or sqlite3_open_v2(). 3234** 3235** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3236** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3237** features that require the use of temporary files may fail. 3238** 3239** See also: [sqlite3_temp_directory] 3240*/ 3241int sqlite3_open( 3242 const char *filename, /* Database filename (UTF-8) */ 3243 sqlite3 **ppDb /* OUT: SQLite db handle */ 3244); 3245int sqlite3_open16( 3246 const void *filename, /* Database filename (UTF-16) */ 3247 sqlite3 **ppDb /* OUT: SQLite db handle */ 3248); 3249int sqlite3_open_v2( 3250 const char *filename, /* Database filename (UTF-8) */ 3251 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3252 int flags, /* Flags */ 3253 const char *zVfs /* Name of VFS module to use */ 3254); 3255 3256/* 3257** CAPI3REF: Obtain Values For URI Parameters 3258** 3259** These are utility routines, useful to VFS implementations, that check 3260** to see if a database file was a URI that contained a specific query 3261** parameter, and if so obtains the value of that query parameter. 3262** 3263** If F is the database filename pointer passed into the xOpen() method of 3264** a VFS implementation when the flags parameter to xOpen() has one or 3265** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3266** P is the name of the query parameter, then 3267** sqlite3_uri_parameter(F,P) returns the value of the P 3268** parameter if it exists or a NULL pointer if P does not appear as a 3269** query parameter on F. If P is a query parameter of F 3270** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3271** a pointer to an empty string. 3272** 3273** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3274** parameter and returns true (1) or false (0) according to the value 3275** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3276** value of query parameter P is one of "yes", "true", or "on" in any 3277** case or if the value begins with a non-zero number. The 3278** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3279** query parameter P is one of "no", "false", or "off" in any case or 3280** if the value begins with a numeric zero. If P is not a query 3281** parameter on F or if the value of P is does not match any of the 3282** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3283** 3284** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3285** 64-bit signed integer and returns that integer, or D if P does not 3286** exist. If the value of P is something other than an integer, then 3287** zero is returned. 3288** 3289** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3290** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3291** is not a database file pathname pointer that SQLite passed into the xOpen 3292** VFS method, then the behavior of this routine is undefined and probably 3293** undesirable. 3294*/ 3295const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3296int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3297sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3298 3299 3300/* 3301** CAPI3REF: Error Codes And Messages 3302** METHOD: sqlite3 3303** 3304** ^If the most recent sqlite3_* API call associated with 3305** [database connection] D failed, then the sqlite3_errcode(D) interface 3306** returns the numeric [result code] or [extended result code] for that 3307** API call. 3308** If the most recent API call was successful, 3309** then the return value from sqlite3_errcode() is undefined. 3310** ^The sqlite3_extended_errcode() 3311** interface is the same except that it always returns the 3312** [extended result code] even when extended result codes are 3313** disabled. 3314** 3315** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3316** text that describes the error, as either UTF-8 or UTF-16 respectively. 3317** ^(Memory to hold the error message string is managed internally. 3318** The application does not need to worry about freeing the result. 3319** However, the error string might be overwritten or deallocated by 3320** subsequent calls to other SQLite interface functions.)^ 3321** 3322** ^The sqlite3_errstr() interface returns the English-language text 3323** that describes the [result code], as UTF-8. 3324** ^(Memory to hold the error message string is managed internally 3325** and must not be freed by the application)^. 3326** 3327** When the serialized [threading mode] is in use, it might be the 3328** case that a second error occurs on a separate thread in between 3329** the time of the first error and the call to these interfaces. 3330** When that happens, the second error will be reported since these 3331** interfaces always report the most recent result. To avoid 3332** this, each thread can obtain exclusive use of the [database connection] D 3333** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3334** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3335** all calls to the interfaces listed here are completed. 3336** 3337** If an interface fails with SQLITE_MISUSE, that means the interface 3338** was invoked incorrectly by the application. In that case, the 3339** error code and message may or may not be set. 3340*/ 3341int sqlite3_errcode(sqlite3 *db); 3342int sqlite3_extended_errcode(sqlite3 *db); 3343const char *sqlite3_errmsg(sqlite3*); 3344const void *sqlite3_errmsg16(sqlite3*); 3345const char *sqlite3_errstr(int); 3346 3347/* 3348** CAPI3REF: Prepared Statement Object 3349** KEYWORDS: {prepared statement} {prepared statements} 3350** 3351** An instance of this object represents a single SQL statement that 3352** has been compiled into binary form and is ready to be evaluated. 3353** 3354** Think of each SQL statement as a separate computer program. The 3355** original SQL text is source code. A prepared statement object 3356** is the compiled object code. All SQL must be converted into a 3357** prepared statement before it can be run. 3358** 3359** The life-cycle of a prepared statement object usually goes like this: 3360** 3361** <ol> 3362** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3363** <li> Bind values to [parameters] using the sqlite3_bind_*() 3364** interfaces. 3365** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3366** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3367** to step 2. Do this zero or more times. 3368** <li> Destroy the object using [sqlite3_finalize()]. 3369** </ol> 3370*/ 3371typedef struct sqlite3_stmt sqlite3_stmt; 3372 3373/* 3374** CAPI3REF: Run-time Limits 3375** METHOD: sqlite3 3376** 3377** ^(This interface allows the size of various constructs to be limited 3378** on a connection by connection basis. The first parameter is the 3379** [database connection] whose limit is to be set or queried. The 3380** second parameter is one of the [limit categories] that define a 3381** class of constructs to be size limited. The third parameter is the 3382** new limit for that construct.)^ 3383** 3384** ^If the new limit is a negative number, the limit is unchanged. 3385** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3386** [limits | hard upper bound] 3387** set at compile-time by a C preprocessor macro called 3388** [limits | SQLITE_MAX_<i>NAME</i>]. 3389** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3390** ^Attempts to increase a limit above its hard upper bound are 3391** silently truncated to the hard upper bound. 3392** 3393** ^Regardless of whether or not the limit was changed, the 3394** [sqlite3_limit()] interface returns the prior value of the limit. 3395** ^Hence, to find the current value of a limit without changing it, 3396** simply invoke this interface with the third parameter set to -1. 3397** 3398** Run-time limits are intended for use in applications that manage 3399** both their own internal database and also databases that are controlled 3400** by untrusted external sources. An example application might be a 3401** web browser that has its own databases for storing history and 3402** separate databases controlled by JavaScript applications downloaded 3403** off the Internet. The internal databases can be given the 3404** large, default limits. Databases managed by external sources can 3405** be given much smaller limits designed to prevent a denial of service 3406** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3407** interface to further control untrusted SQL. The size of the database 3408** created by an untrusted script can be contained using the 3409** [max_page_count] [PRAGMA]. 3410** 3411** New run-time limit categories may be added in future releases. 3412*/ 3413int sqlite3_limit(sqlite3*, int id, int newVal); 3414 3415/* 3416** CAPI3REF: Run-Time Limit Categories 3417** KEYWORDS: {limit category} {*limit categories} 3418** 3419** These constants define various performance limits 3420** that can be lowered at run-time using [sqlite3_limit()]. 3421** The synopsis of the meanings of the various limits is shown below. 3422** Additional information is available at [limits | Limits in SQLite]. 3423** 3424** <dl> 3425** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3426** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3427** 3428** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3429** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3430** 3431** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3432** <dd>The maximum number of columns in a table definition or in the 3433** result set of a [SELECT] or the maximum number of columns in an index 3434** or in an ORDER BY or GROUP BY clause.</dd>)^ 3435** 3436** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3437** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3438** 3439** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3440** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3441** 3442** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3443** <dd>The maximum number of instructions in a virtual machine program 3444** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3445** the equivalent tries to allocate space for more than this many opcodes 3446** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3447** 3448** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3449** <dd>The maximum number of arguments on a function.</dd>)^ 3450** 3451** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3452** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3453** 3454** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3455** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3456** <dd>The maximum length of the pattern argument to the [LIKE] or 3457** [GLOB] operators.</dd>)^ 3458** 3459** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3460** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3461** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3462** 3463** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3464** <dd>The maximum depth of recursion for triggers.</dd>)^ 3465** 3466** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3467** <dd>The maximum number of auxiliary worker threads that a single 3468** [prepared statement] may start.</dd>)^ 3469** </dl> 3470*/ 3471#define SQLITE_LIMIT_LENGTH 0 3472#define SQLITE_LIMIT_SQL_LENGTH 1 3473#define SQLITE_LIMIT_COLUMN 2 3474#define SQLITE_LIMIT_EXPR_DEPTH 3 3475#define SQLITE_LIMIT_COMPOUND_SELECT 4 3476#define SQLITE_LIMIT_VDBE_OP 5 3477#define SQLITE_LIMIT_FUNCTION_ARG 6 3478#define SQLITE_LIMIT_ATTACHED 7 3479#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3480#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3481#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3482#define SQLITE_LIMIT_WORKER_THREADS 11 3483 3484/* 3485** CAPI3REF: Prepare Flags 3486** 3487** These constants define various flags that can be passed into 3488** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3489** [sqlite3_prepare16_v3()] interfaces. 3490** 3491** New flags may be added in future releases of SQLite. 3492** 3493** <dl> 3494** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3495** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3496** that the prepared statement will be retained for a long time and 3497** probably reused many times. ^Without this flag, [sqlite3_prepare_v3()] 3498** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3499** be used just once or at most a few times and then destroyed using 3500** [sqlite3_finalize()] relatively soon. The current implementation acts 3501** on this hint by avoiding the use of [lookaside memory] so as not to 3502** deplete the limited store of lookaside memory. Future versions of 3503** SQLite may act on this hint differently. 3504** </dl> 3505*/ 3506#define SQLITE_PREPARE_PERSISTENT 0x01 3507 3508/* 3509** CAPI3REF: Compiling An SQL Statement 3510** KEYWORDS: {SQL statement compiler} 3511** METHOD: sqlite3 3512** CONSTRUCTOR: sqlite3_stmt 3513** 3514** To execute an SQL statement, it must first be compiled into a byte-code 3515** program using one of these routines. Or, in other words, these routines 3516** are constructors for the [prepared statement] object. 3517** 3518** The preferred routine to use is [sqlite3_prepare_v2()]. The 3519** [sqlite3_prepare()] interface is legacy and should be avoided. 3520** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3521** for special purposes. 3522** 3523** The use of the UTF-8 interfaces is preferred, as SQLite currently 3524** does all parsing using UTF-8. The UTF-16 interfaces are provided 3525** as a convenience. The UTF-16 interfaces work by converting the 3526** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3527** 3528** The first argument, "db", is a [database connection] obtained from a 3529** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3530** [sqlite3_open16()]. The database connection must not have been closed. 3531** 3532** The second argument, "zSql", is the statement to be compiled, encoded 3533** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 3534** and sqlite3_prepare_v3() 3535** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 3536** and sqlite3_prepare16_v3() use UTF-16. 3537** 3538** ^If the nByte argument is negative, then zSql is read up to the 3539** first zero terminator. ^If nByte is positive, then it is the 3540** number of bytes read from zSql. ^If nByte is zero, then no prepared 3541** statement is generated. 3542** If the caller knows that the supplied string is nul-terminated, then 3543** there is a small performance advantage to passing an nByte parameter that 3544** is the number of bytes in the input string <i>including</i> 3545** the nul-terminator. 3546** 3547** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3548** past the end of the first SQL statement in zSql. These routines only 3549** compile the first statement in zSql, so *pzTail is left pointing to 3550** what remains uncompiled. 3551** 3552** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3553** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3554** to NULL. ^If the input text contains no SQL (if the input is an empty 3555** string or a comment) then *ppStmt is set to NULL. 3556** The calling procedure is responsible for deleting the compiled 3557** SQL statement using [sqlite3_finalize()] after it has finished with it. 3558** ppStmt may not be NULL. 3559** 3560** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3561** otherwise an [error code] is returned. 3562** 3563** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 3564** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 3565** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 3566** are retained for backwards compatibility, but their use is discouraged. 3567** ^In the "vX" interfaces, the prepared statement 3568** that is returned (the [sqlite3_stmt] object) contains a copy of the 3569** original SQL text. This causes the [sqlite3_step()] interface to 3570** behave differently in three ways: 3571** 3572** <ol> 3573** <li> 3574** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3575** always used to do, [sqlite3_step()] will automatically recompile the SQL 3576** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3577** retries will occur before sqlite3_step() gives up and returns an error. 3578** </li> 3579** 3580** <li> 3581** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3582** [error codes] or [extended error codes]. ^The legacy behavior was that 3583** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3584** and the application would have to make a second call to [sqlite3_reset()] 3585** in order to find the underlying cause of the problem. With the "v2" prepare 3586** interfaces, the underlying reason for the error is returned immediately. 3587** </li> 3588** 3589** <li> 3590** ^If the specific value bound to [parameter | host parameter] in the 3591** WHERE clause might influence the choice of query plan for a statement, 3592** then the statement will be automatically recompiled, as if there had been 3593** a schema change, on the first [sqlite3_step()] call following any change 3594** to the [sqlite3_bind_text | bindings] of that [parameter]. 3595** ^The specific value of WHERE-clause [parameter] might influence the 3596** choice of query plan if the parameter is the left-hand side of a [LIKE] 3597** or [GLOB] operator or if the parameter is compared to an indexed column 3598** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3599** </li> 3600** 3601** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 3602** the extra prepFlags parameter, which is a bit array consisting of zero or 3603** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 3604** sqlite3_prepare_v2() interface works exactly the same as 3605** sqlite3_prepare_v3() with a zero prepFlags parameter. 3606** </ol> 3607*/ 3608int sqlite3_prepare( 3609 sqlite3 *db, /* Database handle */ 3610 const char *zSql, /* SQL statement, UTF-8 encoded */ 3611 int nByte, /* Maximum length of zSql in bytes. */ 3612 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3613 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3614); 3615int sqlite3_prepare_v2( 3616 sqlite3 *db, /* Database handle */ 3617 const char *zSql, /* SQL statement, UTF-8 encoded */ 3618 int nByte, /* Maximum length of zSql in bytes. */ 3619 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3620 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3621); 3622int sqlite3_prepare_v3( 3623 sqlite3 *db, /* Database handle */ 3624 const char *zSql, /* SQL statement, UTF-8 encoded */ 3625 int nByte, /* Maximum length of zSql in bytes. */ 3626 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3627 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3628 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3629); 3630int sqlite3_prepare16( 3631 sqlite3 *db, /* Database handle */ 3632 const void *zSql, /* SQL statement, UTF-16 encoded */ 3633 int nByte, /* Maximum length of zSql in bytes. */ 3634 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3635 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3636); 3637int sqlite3_prepare16_v2( 3638 sqlite3 *db, /* Database handle */ 3639 const void *zSql, /* SQL statement, UTF-16 encoded */ 3640 int nByte, /* Maximum length of zSql in bytes. */ 3641 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3642 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3643); 3644int sqlite3_prepare16_v3( 3645 sqlite3 *db, /* Database handle */ 3646 const void *zSql, /* SQL statement, UTF-16 encoded */ 3647 int nByte, /* Maximum length of zSql in bytes. */ 3648 unsigned int prepFalgs, /* Zero or more SQLITE_PREPARE_ flags */ 3649 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3650 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3651); 3652 3653/* 3654** CAPI3REF: Retrieving Statement SQL 3655** METHOD: sqlite3_stmt 3656** 3657** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 3658** SQL text used to create [prepared statement] P if P was 3659** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 3660** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 3661** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 3662** string containing the SQL text of prepared statement P with 3663** [bound parameters] expanded. 3664** 3665** ^(For example, if a prepared statement is created using the SQL 3666** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 3667** and parameter :xyz is unbound, then sqlite3_sql() will return 3668** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 3669** will return "SELECT 2345,NULL".)^ 3670** 3671** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 3672** is available to hold the result, or if the result would exceed the 3673** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 3674** 3675** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 3676** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 3677** option causes sqlite3_expanded_sql() to always return NULL. 3678** 3679** ^The string returned by sqlite3_sql(P) is managed by SQLite and is 3680** automatically freed when the prepared statement is finalized. 3681** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 3682** is obtained from [sqlite3_malloc()] and must be free by the application 3683** by passing it to [sqlite3_free()]. 3684*/ 3685const char *sqlite3_sql(sqlite3_stmt *pStmt); 3686char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 3687 3688/* 3689** CAPI3REF: Determine If An SQL Statement Writes The Database 3690** METHOD: sqlite3_stmt 3691** 3692** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3693** and only if the [prepared statement] X makes no direct changes to 3694** the content of the database file. 3695** 3696** Note that [application-defined SQL functions] or 3697** [virtual tables] might change the database indirectly as a side effect. 3698** ^(For example, if an application defines a function "eval()" that 3699** calls [sqlite3_exec()], then the following SQL statement would 3700** change the database file through side-effects: 3701** 3702** <blockquote><pre> 3703** SELECT eval('DELETE FROM t1') FROM t2; 3704** </pre></blockquote> 3705** 3706** But because the [SELECT] statement does not change the database file 3707** directly, sqlite3_stmt_readonly() would still return true.)^ 3708** 3709** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3710** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3711** since the statements themselves do not actually modify the database but 3712** rather they control the timing of when other statements modify the 3713** database. ^The [ATTACH] and [DETACH] statements also cause 3714** sqlite3_stmt_readonly() to return true since, while those statements 3715** change the configuration of a database connection, they do not make 3716** changes to the content of the database files on disk. 3717** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 3718** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 3719** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 3720** sqlite3_stmt_readonly() returns false for those commands. 3721*/ 3722int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3723 3724/* 3725** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3726** METHOD: sqlite3_stmt 3727** 3728** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3729** [prepared statement] S has been stepped at least once using 3730** [sqlite3_step(S)] but has neither run to completion (returned 3731** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3732** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3733** interface returns false if S is a NULL pointer. If S is not a 3734** NULL pointer and is not a pointer to a valid [prepared statement] 3735** object, then the behavior is undefined and probably undesirable. 3736** 3737** This interface can be used in combination [sqlite3_next_stmt()] 3738** to locate all prepared statements associated with a database 3739** connection that are in need of being reset. This can be used, 3740** for example, in diagnostic routines to search for prepared 3741** statements that are holding a transaction open. 3742*/ 3743int sqlite3_stmt_busy(sqlite3_stmt*); 3744 3745/* 3746** CAPI3REF: Dynamically Typed Value Object 3747** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3748** 3749** SQLite uses the sqlite3_value object to represent all values 3750** that can be stored in a database table. SQLite uses dynamic typing 3751** for the values it stores. ^Values stored in sqlite3_value objects 3752** can be integers, floating point values, strings, BLOBs, or NULL. 3753** 3754** An sqlite3_value object may be either "protected" or "unprotected". 3755** Some interfaces require a protected sqlite3_value. Other interfaces 3756** will accept either a protected or an unprotected sqlite3_value. 3757** Every interface that accepts sqlite3_value arguments specifies 3758** whether or not it requires a protected sqlite3_value. The 3759** [sqlite3_value_dup()] interface can be used to construct a new 3760** protected sqlite3_value from an unprotected sqlite3_value. 3761** 3762** The terms "protected" and "unprotected" refer to whether or not 3763** a mutex is held. An internal mutex is held for a protected 3764** sqlite3_value object but no mutex is held for an unprotected 3765** sqlite3_value object. If SQLite is compiled to be single-threaded 3766** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3767** or if SQLite is run in one of reduced mutex modes 3768** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3769** then there is no distinction between protected and unprotected 3770** sqlite3_value objects and they can be used interchangeably. However, 3771** for maximum code portability it is recommended that applications 3772** still make the distinction between protected and unprotected 3773** sqlite3_value objects even when not strictly required. 3774** 3775** ^The sqlite3_value objects that are passed as parameters into the 3776** implementation of [application-defined SQL functions] are protected. 3777** ^The sqlite3_value object returned by 3778** [sqlite3_column_value()] is unprotected. 3779** Unprotected sqlite3_value objects may only be used with 3780** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3781** The [sqlite3_value_blob | sqlite3_value_type()] family of 3782** interfaces require protected sqlite3_value objects. 3783*/ 3784typedef struct sqlite3_value sqlite3_value; 3785 3786/* 3787** CAPI3REF: SQL Function Context Object 3788** 3789** The context in which an SQL function executes is stored in an 3790** sqlite3_context object. ^A pointer to an sqlite3_context object 3791** is always first parameter to [application-defined SQL functions]. 3792** The application-defined SQL function implementation will pass this 3793** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3794** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3795** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3796** and/or [sqlite3_set_auxdata()]. 3797*/ 3798typedef struct sqlite3_context sqlite3_context; 3799 3800/* 3801** CAPI3REF: Binding Values To Prepared Statements 3802** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3803** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3804** METHOD: sqlite3_stmt 3805** 3806** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3807** literals may be replaced by a [parameter] that matches one of following 3808** templates: 3809** 3810** <ul> 3811** <li> ? 3812** <li> ?NNN 3813** <li> :VVV 3814** <li> @VVV 3815** <li> $VVV 3816** </ul> 3817** 3818** In the templates above, NNN represents an integer literal, 3819** and VVV represents an alphanumeric identifier.)^ ^The values of these 3820** parameters (also called "host parameter names" or "SQL parameters") 3821** can be set using the sqlite3_bind_*() routines defined here. 3822** 3823** ^The first argument to the sqlite3_bind_*() routines is always 3824** a pointer to the [sqlite3_stmt] object returned from 3825** [sqlite3_prepare_v2()] or its variants. 3826** 3827** ^The second argument is the index of the SQL parameter to be set. 3828** ^The leftmost SQL parameter has an index of 1. ^When the same named 3829** SQL parameter is used more than once, second and subsequent 3830** occurrences have the same index as the first occurrence. 3831** ^The index for named parameters can be looked up using the 3832** [sqlite3_bind_parameter_index()] API if desired. ^The index 3833** for "?NNN" parameters is the value of NNN. 3834** ^The NNN value must be between 1 and the [sqlite3_limit()] 3835** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3836** 3837** ^The third argument is the value to bind to the parameter. 3838** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3839** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3840** is ignored and the end result is the same as sqlite3_bind_null(). 3841** 3842** ^(In those routines that have a fourth argument, its value is the 3843** number of bytes in the parameter. To be clear: the value is the 3844** number of <u>bytes</u> in the value, not the number of characters.)^ 3845** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3846** is negative, then the length of the string is 3847** the number of bytes up to the first zero terminator. 3848** If the fourth parameter to sqlite3_bind_blob() is negative, then 3849** the behavior is undefined. 3850** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3851** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3852** that parameter must be the byte offset 3853** where the NUL terminator would occur assuming the string were NUL 3854** terminated. If any NUL characters occur at byte offsets less than 3855** the value of the fourth parameter then the resulting string value will 3856** contain embedded NULs. The result of expressions involving strings 3857** with embedded NULs is undefined. 3858** 3859** ^The fifth argument to the BLOB and string binding interfaces 3860** is a destructor used to dispose of the BLOB or 3861** string after SQLite has finished with it. ^The destructor is called 3862** to dispose of the BLOB or string even if the call to bind API fails. 3863** ^If the fifth argument is 3864** the special value [SQLITE_STATIC], then SQLite assumes that the 3865** information is in static, unmanaged space and does not need to be freed. 3866** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3867** SQLite makes its own private copy of the data immediately, before 3868** the sqlite3_bind_*() routine returns. 3869** 3870** ^The sixth argument to sqlite3_bind_text64() must be one of 3871** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3872** to specify the encoding of the text in the third parameter. If 3873** the sixth argument to sqlite3_bind_text64() is not one of the 3874** allowed values shown above, or if the text encoding is different 3875** from the encoding specified by the sixth parameter, then the behavior 3876** is undefined. 3877** 3878** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3879** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3880** (just an integer to hold its size) while it is being processed. 3881** Zeroblobs are intended to serve as placeholders for BLOBs whose 3882** content is later written using 3883** [sqlite3_blob_open | incremental BLOB I/O] routines. 3884** ^A negative value for the zeroblob results in a zero-length BLOB. 3885** 3886** ^The sqlite3_bind_pointer(S,I,P) routine causes the I-th parameter in 3887** [prepared statement] S to have an SQL value of NULL, but to also be 3888** associated with the pointer P. 3889** ^The sqlite3_bind_pointer() routine can be used to pass 3890** host-language pointers into [application-defined SQL functions]. 3891** ^A parameter that is initialized using [sqlite3_bind_pointer()] appears 3892** to be an ordinary SQL NULL value to everything other than 3893** [sqlite3_value_pointer()]. 3894** 3895** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3896** for the [prepared statement] or with a prepared statement for which 3897** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3898** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3899** routine is passed a [prepared statement] that has been finalized, the 3900** result is undefined and probably harmful. 3901** 3902** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3903** ^Unbound parameters are interpreted as NULL. 3904** 3905** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3906** [error code] if anything goes wrong. 3907** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3908** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3909** [SQLITE_MAX_LENGTH]. 3910** ^[SQLITE_RANGE] is returned if the parameter 3911** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3912** 3913** See also: [sqlite3_bind_parameter_count()], 3914** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3915*/ 3916int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3917int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3918 void(*)(void*)); 3919int sqlite3_bind_double(sqlite3_stmt*, int, double); 3920int sqlite3_bind_int(sqlite3_stmt*, int, int); 3921int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3922int sqlite3_bind_null(sqlite3_stmt*, int); 3923int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3924int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3925int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3926 void(*)(void*), unsigned char encoding); 3927int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3928int sqlite3_bind_pointer(sqlite3_stmt*, int, void*); 3929int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3930int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 3931 3932/* 3933** CAPI3REF: Number Of SQL Parameters 3934** METHOD: sqlite3_stmt 3935** 3936** ^This routine can be used to find the number of [SQL parameters] 3937** in a [prepared statement]. SQL parameters are tokens of the 3938** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3939** placeholders for values that are [sqlite3_bind_blob | bound] 3940** to the parameters at a later time. 3941** 3942** ^(This routine actually returns the index of the largest (rightmost) 3943** parameter. For all forms except ?NNN, this will correspond to the 3944** number of unique parameters. If parameters of the ?NNN form are used, 3945** there may be gaps in the list.)^ 3946** 3947** See also: [sqlite3_bind_blob|sqlite3_bind()], 3948** [sqlite3_bind_parameter_name()], and 3949** [sqlite3_bind_parameter_index()]. 3950*/ 3951int sqlite3_bind_parameter_count(sqlite3_stmt*); 3952 3953/* 3954** CAPI3REF: Name Of A Host Parameter 3955** METHOD: sqlite3_stmt 3956** 3957** ^The sqlite3_bind_parameter_name(P,N) interface returns 3958** the name of the N-th [SQL parameter] in the [prepared statement] P. 3959** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3960** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3961** respectively. 3962** In other words, the initial ":" or "$" or "@" or "?" 3963** is included as part of the name.)^ 3964** ^Parameters of the form "?" without a following integer have no name 3965** and are referred to as "nameless" or "anonymous parameters". 3966** 3967** ^The first host parameter has an index of 1, not 0. 3968** 3969** ^If the value N is out of range or if the N-th parameter is 3970** nameless, then NULL is returned. ^The returned string is 3971** always in UTF-8 encoding even if the named parameter was 3972** originally specified as UTF-16 in [sqlite3_prepare16()], 3973** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 3974** 3975** See also: [sqlite3_bind_blob|sqlite3_bind()], 3976** [sqlite3_bind_parameter_count()], and 3977** [sqlite3_bind_parameter_index()]. 3978*/ 3979const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3980 3981/* 3982** CAPI3REF: Index Of A Parameter With A Given Name 3983** METHOD: sqlite3_stmt 3984** 3985** ^Return the index of an SQL parameter given its name. ^The 3986** index value returned is suitable for use as the second 3987** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3988** is returned if no matching parameter is found. ^The parameter 3989** name must be given in UTF-8 even if the original statement 3990** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 3991** [sqlite3_prepare16_v3()]. 3992** 3993** See also: [sqlite3_bind_blob|sqlite3_bind()], 3994** [sqlite3_bind_parameter_count()], and 3995** [sqlite3_bind_parameter_name()]. 3996*/ 3997int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3998 3999/* 4000** CAPI3REF: Reset All Bindings On A Prepared Statement 4001** METHOD: sqlite3_stmt 4002** 4003** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4004** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4005** ^Use this routine to reset all host parameters to NULL. 4006*/ 4007int sqlite3_clear_bindings(sqlite3_stmt*); 4008 4009/* 4010** CAPI3REF: Number Of Columns In A Result Set 4011** METHOD: sqlite3_stmt 4012** 4013** ^Return the number of columns in the result set returned by the 4014** [prepared statement]. ^If this routine returns 0, that means the 4015** [prepared statement] returns no data (for example an [UPDATE]). 4016** ^However, just because this routine returns a positive number does not 4017** mean that one or more rows of data will be returned. ^A SELECT statement 4018** will always have a positive sqlite3_column_count() but depending on the 4019** WHERE clause constraints and the table content, it might return no rows. 4020** 4021** See also: [sqlite3_data_count()] 4022*/ 4023int sqlite3_column_count(sqlite3_stmt *pStmt); 4024 4025/* 4026** CAPI3REF: Column Names In A Result Set 4027** METHOD: sqlite3_stmt 4028** 4029** ^These routines return the name assigned to a particular column 4030** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4031** interface returns a pointer to a zero-terminated UTF-8 string 4032** and sqlite3_column_name16() returns a pointer to a zero-terminated 4033** UTF-16 string. ^The first parameter is the [prepared statement] 4034** that implements the [SELECT] statement. ^The second parameter is the 4035** column number. ^The leftmost column is number 0. 4036** 4037** ^The returned string pointer is valid until either the [prepared statement] 4038** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4039** reprepared by the first call to [sqlite3_step()] for a particular run 4040** or until the next call to 4041** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4042** 4043** ^If sqlite3_malloc() fails during the processing of either routine 4044** (for example during a conversion from UTF-8 to UTF-16) then a 4045** NULL pointer is returned. 4046** 4047** ^The name of a result column is the value of the "AS" clause for 4048** that column, if there is an AS clause. If there is no AS clause 4049** then the name of the column is unspecified and may change from 4050** one release of SQLite to the next. 4051*/ 4052const char *sqlite3_column_name(sqlite3_stmt*, int N); 4053const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4054 4055/* 4056** CAPI3REF: Source Of Data In A Query Result 4057** METHOD: sqlite3_stmt 4058** 4059** ^These routines provide a means to determine the database, table, and 4060** table column that is the origin of a particular result column in 4061** [SELECT] statement. 4062** ^The name of the database or table or column can be returned as 4063** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4064** the database name, the _table_ routines return the table name, and 4065** the origin_ routines return the column name. 4066** ^The returned string is valid until the [prepared statement] is destroyed 4067** using [sqlite3_finalize()] or until the statement is automatically 4068** reprepared by the first call to [sqlite3_step()] for a particular run 4069** or until the same information is requested 4070** again in a different encoding. 4071** 4072** ^The names returned are the original un-aliased names of the 4073** database, table, and column. 4074** 4075** ^The first argument to these interfaces is a [prepared statement]. 4076** ^These functions return information about the Nth result column returned by 4077** the statement, where N is the second function argument. 4078** ^The left-most column is column 0 for these routines. 4079** 4080** ^If the Nth column returned by the statement is an expression or 4081** subquery and is not a column value, then all of these functions return 4082** NULL. ^These routine might also return NULL if a memory allocation error 4083** occurs. ^Otherwise, they return the name of the attached database, table, 4084** or column that query result column was extracted from. 4085** 4086** ^As with all other SQLite APIs, those whose names end with "16" return 4087** UTF-16 encoded strings and the other functions return UTF-8. 4088** 4089** ^These APIs are only available if the library was compiled with the 4090** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4091** 4092** If two or more threads call one or more of these routines against the same 4093** prepared statement and column at the same time then the results are 4094** undefined. 4095** 4096** If two or more threads call one or more 4097** [sqlite3_column_database_name | column metadata interfaces] 4098** for the same [prepared statement] and result column 4099** at the same time then the results are undefined. 4100*/ 4101const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4102const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4103const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4104const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4105const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4106const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4107 4108/* 4109** CAPI3REF: Declared Datatype Of A Query Result 4110** METHOD: sqlite3_stmt 4111** 4112** ^(The first parameter is a [prepared statement]. 4113** If this statement is a [SELECT] statement and the Nth column of the 4114** returned result set of that [SELECT] is a table column (not an 4115** expression or subquery) then the declared type of the table 4116** column is returned.)^ ^If the Nth column of the result set is an 4117** expression or subquery, then a NULL pointer is returned. 4118** ^The returned string is always UTF-8 encoded. 4119** 4120** ^(For example, given the database schema: 4121** 4122** CREATE TABLE t1(c1 VARIANT); 4123** 4124** and the following statement to be compiled: 4125** 4126** SELECT c1 + 1, c1 FROM t1; 4127** 4128** this routine would return the string "VARIANT" for the second result 4129** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4130** 4131** ^SQLite uses dynamic run-time typing. ^So just because a column 4132** is declared to contain a particular type does not mean that the 4133** data stored in that column is of the declared type. SQLite is 4134** strongly typed, but the typing is dynamic not static. ^Type 4135** is associated with individual values, not with the containers 4136** used to hold those values. 4137*/ 4138const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4139const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4140 4141/* 4142** CAPI3REF: Evaluate An SQL Statement 4143** METHOD: sqlite3_stmt 4144** 4145** After a [prepared statement] has been prepared using any of 4146** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4147** or [sqlite3_prepare16_v3()] or one of the legacy 4148** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4149** must be called one or more times to evaluate the statement. 4150** 4151** The details of the behavior of the sqlite3_step() interface depend 4152** on whether the statement was prepared using the newer "vX" interfaces 4153** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4154** [sqlite3_prepare16_v2()] or the older legacy 4155** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4156** new "vX" interface is recommended for new applications but the legacy 4157** interface will continue to be supported. 4158** 4159** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4160** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4161** ^With the "v2" interface, any of the other [result codes] or 4162** [extended result codes] might be returned as well. 4163** 4164** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4165** database locks it needs to do its job. ^If the statement is a [COMMIT] 4166** or occurs outside of an explicit transaction, then you can retry the 4167** statement. If the statement is not a [COMMIT] and occurs within an 4168** explicit transaction then you should rollback the transaction before 4169** continuing. 4170** 4171** ^[SQLITE_DONE] means that the statement has finished executing 4172** successfully. sqlite3_step() should not be called again on this virtual 4173** machine without first calling [sqlite3_reset()] to reset the virtual 4174** machine back to its initial state. 4175** 4176** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4177** is returned each time a new row of data is ready for processing by the 4178** caller. The values may be accessed using the [column access functions]. 4179** sqlite3_step() is called again to retrieve the next row of data. 4180** 4181** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4182** violation) has occurred. sqlite3_step() should not be called again on 4183** the VM. More information may be found by calling [sqlite3_errmsg()]. 4184** ^With the legacy interface, a more specific error code (for example, 4185** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4186** can be obtained by calling [sqlite3_reset()] on the 4187** [prepared statement]. ^In the "v2" interface, 4188** the more specific error code is returned directly by sqlite3_step(). 4189** 4190** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4191** Perhaps it was called on a [prepared statement] that has 4192** already been [sqlite3_finalize | finalized] or on one that had 4193** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4194** be the case that the same database connection is being used by two or 4195** more threads at the same moment in time. 4196** 4197** For all versions of SQLite up to and including 3.6.23.1, a call to 4198** [sqlite3_reset()] was required after sqlite3_step() returned anything 4199** other than [SQLITE_ROW] before any subsequent invocation of 4200** sqlite3_step(). Failure to reset the prepared statement using 4201** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4202** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4203** sqlite3_step() began 4204** calling [sqlite3_reset()] automatically in this circumstance rather 4205** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4206** break because any application that ever receives an SQLITE_MISUSE error 4207** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4208** can be used to restore the legacy behavior. 4209** 4210** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4211** API always returns a generic error code, [SQLITE_ERROR], following any 4212** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4213** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4214** specific [error codes] that better describes the error. 4215** We admit that this is a goofy design. The problem has been fixed 4216** with the "v2" interface. If you prepare all of your SQL statements 4217** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4218** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4219** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4220** then the more specific [error codes] are returned directly 4221** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4222*/ 4223int sqlite3_step(sqlite3_stmt*); 4224 4225/* 4226** CAPI3REF: Number of columns in a result set 4227** METHOD: sqlite3_stmt 4228** 4229** ^The sqlite3_data_count(P) interface returns the number of columns in the 4230** current row of the result set of [prepared statement] P. 4231** ^If prepared statement P does not have results ready to return 4232** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 4233** interfaces) then sqlite3_data_count(P) returns 0. 4234** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4235** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4236** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4237** will return non-zero if previous call to [sqlite3_step](P) returned 4238** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4239** where it always returns zero since each step of that multi-step 4240** pragma returns 0 columns of data. 4241** 4242** See also: [sqlite3_column_count()] 4243*/ 4244int sqlite3_data_count(sqlite3_stmt *pStmt); 4245 4246/* 4247** CAPI3REF: Fundamental Datatypes 4248** KEYWORDS: SQLITE_TEXT 4249** 4250** ^(Every value in SQLite has one of five fundamental datatypes: 4251** 4252** <ul> 4253** <li> 64-bit signed integer 4254** <li> 64-bit IEEE floating point number 4255** <li> string 4256** <li> BLOB 4257** <li> NULL 4258** </ul>)^ 4259** 4260** These constants are codes for each of those types. 4261** 4262** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4263** for a completely different meaning. Software that links against both 4264** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4265** SQLITE_TEXT. 4266*/ 4267#define SQLITE_INTEGER 1 4268#define SQLITE_FLOAT 2 4269#define SQLITE_BLOB 4 4270#define SQLITE_NULL 5 4271#ifdef SQLITE_TEXT 4272# undef SQLITE_TEXT 4273#else 4274# define SQLITE_TEXT 3 4275#endif 4276#define SQLITE3_TEXT 3 4277 4278/* 4279** CAPI3REF: Result Values From A Query 4280** KEYWORDS: {column access functions} 4281** METHOD: sqlite3_stmt 4282** 4283** <b>Summary:</b> 4284** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4285** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4286** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4287** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4288** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4289** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4290** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4291** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4292** [sqlite3_value|unprotected sqlite3_value] object. 4293** <tr><td> <td> <td> 4294** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4295** or a UTF-8 TEXT result in bytes 4296** <tr><td><b>sqlite3_column_bytes16 </b> 4297** <td>→ <td>Size of UTF-16 4298** TEXT in bytes 4299** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4300** datatype of the result 4301** </table></blockquote> 4302** 4303** <b>Details:</b> 4304** 4305** ^These routines return information about a single column of the current 4306** result row of a query. ^In every case the first argument is a pointer 4307** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4308** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4309** and the second argument is the index of the column for which information 4310** should be returned. ^The leftmost column of the result set has the index 0. 4311** ^The number of columns in the result can be determined using 4312** [sqlite3_column_count()]. 4313** 4314** If the SQL statement does not currently point to a valid row, or if the 4315** column index is out of range, the result is undefined. 4316** These routines may only be called when the most recent call to 4317** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4318** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4319** If any of these routines are called after [sqlite3_reset()] or 4320** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4321** something other than [SQLITE_ROW], the results are undefined. 4322** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4323** are called from a different thread while any of these routines 4324** are pending, then the results are undefined. 4325** 4326** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4327** each return the value of a result column in a specific data format. If 4328** the result column is not initially in the requested format (for example, 4329** if the query returns an integer but the sqlite3_column_text() interface 4330** is used to extract the value) then an automatic type conversion is performed. 4331** 4332** ^The sqlite3_column_type() routine returns the 4333** [SQLITE_INTEGER | datatype code] for the initial data type 4334** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4335** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4336** The return value of sqlite3_column_type() can be used to decide which 4337** of the first six interface should be used to extract the column value. 4338** The value returned by sqlite3_column_type() is only meaningful if no 4339** automatic type conversions have occurred for the value in question. 4340** After a type conversion, the result of calling sqlite3_column_type() 4341** is undefined, though harmless. Future 4342** versions of SQLite may change the behavior of sqlite3_column_type() 4343** following a type conversion. 4344** 4345** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4346** or sqlite3_column_bytes16() interfaces can be used to determine the size 4347** of that BLOB or string. 4348** 4349** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4350** routine returns the number of bytes in that BLOB or string. 4351** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4352** the string to UTF-8 and then returns the number of bytes. 4353** ^If the result is a numeric value then sqlite3_column_bytes() uses 4354** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4355** the number of bytes in that string. 4356** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4357** 4358** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4359** routine returns the number of bytes in that BLOB or string. 4360** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4361** the string to UTF-16 and then returns the number of bytes. 4362** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4363** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4364** the number of bytes in that string. 4365** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4366** 4367** ^The values returned by [sqlite3_column_bytes()] and 4368** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4369** of the string. ^For clarity: the values returned by 4370** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4371** bytes in the string, not the number of characters. 4372** 4373** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4374** even empty strings, are always zero-terminated. ^The return 4375** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4376** 4377** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4378** [unprotected sqlite3_value] object. In a multithreaded environment, 4379** an unprotected sqlite3_value object may only be used safely with 4380** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4381** If the [unprotected sqlite3_value] object returned by 4382** [sqlite3_column_value()] is used in any other way, including calls 4383** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4384** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4385** Hence, the sqlite3_column_value() interface 4386** is normally only useful within the implementation of 4387** [application-defined SQL functions] or [virtual tables], not within 4388** top-level application code. 4389** 4390** The these routines may attempt to convert the datatype of the result. 4391** ^For example, if the internal representation is FLOAT and a text result 4392** is requested, [sqlite3_snprintf()] is used internally to perform the 4393** conversion automatically. ^(The following table details the conversions 4394** that are applied: 4395** 4396** <blockquote> 4397** <table border="1"> 4398** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4399** 4400** <tr><td> NULL <td> INTEGER <td> Result is 0 4401** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4402** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4403** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4404** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4405** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4406** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4407** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4408** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4409** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4410** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4411** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4412** <tr><td> TEXT <td> BLOB <td> No change 4413** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4414** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4415** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4416** </table> 4417** </blockquote>)^ 4418** 4419** Note that when type conversions occur, pointers returned by prior 4420** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4421** sqlite3_column_text16() may be invalidated. 4422** Type conversions and pointer invalidations might occur 4423** in the following cases: 4424** 4425** <ul> 4426** <li> The initial content is a BLOB and sqlite3_column_text() or 4427** sqlite3_column_text16() is called. A zero-terminator might 4428** need to be added to the string.</li> 4429** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4430** sqlite3_column_text16() is called. The content must be converted 4431** to UTF-16.</li> 4432** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4433** sqlite3_column_text() is called. The content must be converted 4434** to UTF-8.</li> 4435** </ul> 4436** 4437** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4438** not invalidate a prior pointer, though of course the content of the buffer 4439** that the prior pointer references will have been modified. Other kinds 4440** of conversion are done in place when it is possible, but sometimes they 4441** are not possible and in those cases prior pointers are invalidated. 4442** 4443** The safest policy is to invoke these routines 4444** in one of the following ways: 4445** 4446** <ul> 4447** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4448** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4449** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4450** </ul> 4451** 4452** In other words, you should call sqlite3_column_text(), 4453** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4454** into the desired format, then invoke sqlite3_column_bytes() or 4455** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4456** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4457** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4458** with calls to sqlite3_column_bytes(). 4459** 4460** ^The pointers returned are valid until a type conversion occurs as 4461** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4462** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4463** and BLOBs is freed automatically. Do not pass the pointers returned 4464** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4465** [sqlite3_free()]. 4466** 4467** ^(If a memory allocation error occurs during the evaluation of any 4468** of these routines, a default value is returned. The default value 4469** is either the integer 0, the floating point number 0.0, or a NULL 4470** pointer. Subsequent calls to [sqlite3_errcode()] will return 4471** [SQLITE_NOMEM].)^ 4472*/ 4473const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4474double sqlite3_column_double(sqlite3_stmt*, int iCol); 4475int sqlite3_column_int(sqlite3_stmt*, int iCol); 4476sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4477const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4478const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4479sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4480int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4481int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4482int sqlite3_column_type(sqlite3_stmt*, int iCol); 4483 4484/* 4485** CAPI3REF: Destroy A Prepared Statement Object 4486** DESTRUCTOR: sqlite3_stmt 4487** 4488** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4489** ^If the most recent evaluation of the statement encountered no errors 4490** or if the statement is never been evaluated, then sqlite3_finalize() returns 4491** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4492** sqlite3_finalize(S) returns the appropriate [error code] or 4493** [extended error code]. 4494** 4495** ^The sqlite3_finalize(S) routine can be called at any point during 4496** the life cycle of [prepared statement] S: 4497** before statement S is ever evaluated, after 4498** one or more calls to [sqlite3_reset()], or after any call 4499** to [sqlite3_step()] regardless of whether or not the statement has 4500** completed execution. 4501** 4502** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4503** 4504** The application must finalize every [prepared statement] in order to avoid 4505** resource leaks. It is a grievous error for the application to try to use 4506** a prepared statement after it has been finalized. Any use of a prepared 4507** statement after it has been finalized can result in undefined and 4508** undesirable behavior such as segfaults and heap corruption. 4509*/ 4510int sqlite3_finalize(sqlite3_stmt *pStmt); 4511 4512/* 4513** CAPI3REF: Reset A Prepared Statement Object 4514** METHOD: sqlite3_stmt 4515** 4516** The sqlite3_reset() function is called to reset a [prepared statement] 4517** object back to its initial state, ready to be re-executed. 4518** ^Any SQL statement variables that had values bound to them using 4519** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4520** Use [sqlite3_clear_bindings()] to reset the bindings. 4521** 4522** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4523** back to the beginning of its program. 4524** 4525** ^If the most recent call to [sqlite3_step(S)] for the 4526** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4527** or if [sqlite3_step(S)] has never before been called on S, 4528** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4529** 4530** ^If the most recent call to [sqlite3_step(S)] for the 4531** [prepared statement] S indicated an error, then 4532** [sqlite3_reset(S)] returns an appropriate [error code]. 4533** 4534** ^The [sqlite3_reset(S)] interface does not change the values 4535** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4536*/ 4537int sqlite3_reset(sqlite3_stmt *pStmt); 4538 4539/* 4540** CAPI3REF: Create Or Redefine SQL Functions 4541** KEYWORDS: {function creation routines} 4542** KEYWORDS: {application-defined SQL function} 4543** KEYWORDS: {application-defined SQL functions} 4544** METHOD: sqlite3 4545** 4546** ^These functions (collectively known as "function creation routines") 4547** are used to add SQL functions or aggregates or to redefine the behavior 4548** of existing SQL functions or aggregates. The only differences between 4549** these routines are the text encoding expected for 4550** the second parameter (the name of the function being created) 4551** and the presence or absence of a destructor callback for 4552** the application data pointer. 4553** 4554** ^The first parameter is the [database connection] to which the SQL 4555** function is to be added. ^If an application uses more than one database 4556** connection then application-defined SQL functions must be added 4557** to each database connection separately. 4558** 4559** ^The second parameter is the name of the SQL function to be created or 4560** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4561** representation, exclusive of the zero-terminator. ^Note that the name 4562** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4563** ^Any attempt to create a function with a longer name 4564** will result in [SQLITE_MISUSE] being returned. 4565** 4566** ^The third parameter (nArg) 4567** is the number of arguments that the SQL function or 4568** aggregate takes. ^If this parameter is -1, then the SQL function or 4569** aggregate may take any number of arguments between 0 and the limit 4570** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4571** parameter is less than -1 or greater than 127 then the behavior is 4572** undefined. 4573** 4574** ^The fourth parameter, eTextRep, specifies what 4575** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4576** its parameters. The application should set this parameter to 4577** [SQLITE_UTF16LE] if the function implementation invokes 4578** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4579** implementation invokes [sqlite3_value_text16be()] on an input, or 4580** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4581** otherwise. ^The same SQL function may be registered multiple times using 4582** different preferred text encodings, with different implementations for 4583** each encoding. 4584** ^When multiple implementations of the same function are available, SQLite 4585** will pick the one that involves the least amount of data conversion. 4586** 4587** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4588** to signal that the function will always return the same result given 4589** the same inputs within a single SQL statement. Most SQL functions are 4590** deterministic. The built-in [random()] SQL function is an example of a 4591** function that is not deterministic. The SQLite query planner is able to 4592** perform additional optimizations on deterministic functions, so use 4593** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4594** 4595** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4596** function can gain access to this pointer using [sqlite3_user_data()].)^ 4597** 4598** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4599** pointers to C-language functions that implement the SQL function or 4600** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4601** callback only; NULL pointers must be passed as the xStep and xFinal 4602** parameters. ^An aggregate SQL function requires an implementation of xStep 4603** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4604** SQL function or aggregate, pass NULL pointers for all three function 4605** callbacks. 4606** 4607** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4608** then it is destructor for the application data pointer. 4609** The destructor is invoked when the function is deleted, either by being 4610** overloaded or when the database connection closes.)^ 4611** ^The destructor is also invoked if the call to 4612** sqlite3_create_function_v2() fails. 4613** ^When the destructor callback of the tenth parameter is invoked, it 4614** is passed a single argument which is a copy of the application data 4615** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4616** 4617** ^It is permitted to register multiple implementations of the same 4618** functions with the same name but with either differing numbers of 4619** arguments or differing preferred text encodings. ^SQLite will use 4620** the implementation that most closely matches the way in which the 4621** SQL function is used. ^A function implementation with a non-negative 4622** nArg parameter is a better match than a function implementation with 4623** a negative nArg. ^A function where the preferred text encoding 4624** matches the database encoding is a better 4625** match than a function where the encoding is different. 4626** ^A function where the encoding difference is between UTF16le and UTF16be 4627** is a closer match than a function where the encoding difference is 4628** between UTF8 and UTF16. 4629** 4630** ^Built-in functions may be overloaded by new application-defined functions. 4631** 4632** ^An application-defined function is permitted to call other 4633** SQLite interfaces. However, such calls must not 4634** close the database connection nor finalize or reset the prepared 4635** statement in which the function is running. 4636*/ 4637int sqlite3_create_function( 4638 sqlite3 *db, 4639 const char *zFunctionName, 4640 int nArg, 4641 int eTextRep, 4642 void *pApp, 4643 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4644 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4645 void (*xFinal)(sqlite3_context*) 4646); 4647int sqlite3_create_function16( 4648 sqlite3 *db, 4649 const void *zFunctionName, 4650 int nArg, 4651 int eTextRep, 4652 void *pApp, 4653 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4654 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4655 void (*xFinal)(sqlite3_context*) 4656); 4657int sqlite3_create_function_v2( 4658 sqlite3 *db, 4659 const char *zFunctionName, 4660 int nArg, 4661 int eTextRep, 4662 void *pApp, 4663 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4664 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4665 void (*xFinal)(sqlite3_context*), 4666 void(*xDestroy)(void*) 4667); 4668 4669/* 4670** CAPI3REF: Text Encodings 4671** 4672** These constant define integer codes that represent the various 4673** text encodings supported by SQLite. 4674*/ 4675#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4676#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4677#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4678#define SQLITE_UTF16 4 /* Use native byte order */ 4679#define SQLITE_ANY 5 /* Deprecated */ 4680#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4681 4682/* 4683** CAPI3REF: Function Flags 4684** 4685** These constants may be ORed together with the 4686** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4687** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4688** [sqlite3_create_function_v2()]. 4689*/ 4690#define SQLITE_DETERMINISTIC 0x800 4691 4692/* 4693** CAPI3REF: Deprecated Functions 4694** DEPRECATED 4695** 4696** These functions are [deprecated]. In order to maintain 4697** backwards compatibility with older code, these functions continue 4698** to be supported. However, new applications should avoid 4699** the use of these functions. To encourage programmers to avoid 4700** these functions, we will not explain what they do. 4701*/ 4702#ifndef SQLITE_OMIT_DEPRECATED 4703SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4704SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4705SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4706SQLITE_DEPRECATED int sqlite3_global_recover(void); 4707SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4708SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4709 void*,sqlite3_int64); 4710#endif 4711 4712/* 4713** CAPI3REF: Obtaining SQL Values 4714** METHOD: sqlite3_value 4715** 4716** <b>Summary:</b> 4717** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4718** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 4719** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 4720** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 4721** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 4722** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 4723** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 4724** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 4725** the native byteorder 4726** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 4727** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 4728** <tr><td> <td> <td> 4729** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 4730** or a UTF-8 TEXT in bytes 4731** <tr><td><b>sqlite3_value_bytes16 </b> 4732** <td>→ <td>Size of UTF-16 4733** TEXT in bytes 4734** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 4735** datatype of the value 4736** <tr><td><b>sqlite3_value_numeric_type </b> 4737** <td>→ <td>Best numeric datatype of the value 4738** </table></blockquote> 4739** 4740** <b>Details:</b> 4741** 4742** This routine extract type, size, and content information from 4743** [protected sqlite3_value] objects. Protected sqlite3_value objects 4744** are used to pass parameter information into implementation of 4745** [application-defined SQL functions] and [virtual tables]. 4746** 4747** These routines work only with [protected sqlite3_value] objects. 4748** Any attempt to use these routines on an [unprotected sqlite3_value] 4749** is not threadsafe. 4750** 4751** ^These routines work just like the corresponding [column access functions] 4752** except that these routines take a single [protected sqlite3_value] object 4753** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4754** 4755** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4756** in the native byte-order of the host machine. ^The 4757** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4758** extract UTF-16 strings as big-endian and little-endian respectively. 4759** 4760** ^If [sqlite3_value] object V was initialized 4761** using [sqlite3_bind_pointer(S,I,P)] or [sqlite3_result_pointer(C,P)], then 4762** sqlite3_value_pointer(V) will return the pointer P. Otherwise, 4763** sqlite3_value_pointer(V) returns a NULL. 4764** 4765** ^(The sqlite3_value_type(V) interface returns the 4766** [SQLITE_INTEGER | datatype code] for the initial datatype of the 4767** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 4768** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 4769** Other interfaces might change the datatype for an sqlite3_value object. 4770** For example, if the datatype is initially SQLITE_INTEGER and 4771** sqlite3_value_text(V) is called to extract a text value for that 4772** integer, then subsequent calls to sqlite3_value_type(V) might return 4773** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 4774** occurs is undefined and may change from one release of SQLite to the next. 4775** 4776** ^(The sqlite3_value_numeric_type() interface attempts to apply 4777** numeric affinity to the value. This means that an attempt is 4778** made to convert the value to an integer or floating point. If 4779** such a conversion is possible without loss of information (in other 4780** words, if the value is a string that looks like a number) 4781** then the conversion is performed. Otherwise no conversion occurs. 4782** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4783** 4784** Please pay particular attention to the fact that the pointer returned 4785** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4786** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4787** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4788** or [sqlite3_value_text16()]. 4789** 4790** These routines must be called from the same thread as 4791** the SQL function that supplied the [sqlite3_value*] parameters. 4792*/ 4793const void *sqlite3_value_blob(sqlite3_value*); 4794double sqlite3_value_double(sqlite3_value*); 4795int sqlite3_value_int(sqlite3_value*); 4796sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4797void *sqlite3_value_pointer(sqlite3_value*); 4798const unsigned char *sqlite3_value_text(sqlite3_value*); 4799const void *sqlite3_value_text16(sqlite3_value*); 4800const void *sqlite3_value_text16le(sqlite3_value*); 4801const void *sqlite3_value_text16be(sqlite3_value*); 4802int sqlite3_value_bytes(sqlite3_value*); 4803int sqlite3_value_bytes16(sqlite3_value*); 4804int sqlite3_value_type(sqlite3_value*); 4805int sqlite3_value_numeric_type(sqlite3_value*); 4806 4807/* 4808** CAPI3REF: Finding The Subtype Of SQL Values 4809** METHOD: sqlite3_value 4810** 4811** The sqlite3_value_subtype(V) function returns the subtype for 4812** an [application-defined SQL function] argument V. The subtype 4813** information can be used to pass a limited amount of context from 4814** one SQL function to another. Use the [sqlite3_result_subtype()] 4815** routine to set the subtype for the return value of an SQL function. 4816*/ 4817unsigned int sqlite3_value_subtype(sqlite3_value*); 4818 4819/* 4820** CAPI3REF: Copy And Free SQL Values 4821** METHOD: sqlite3_value 4822** 4823** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 4824** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 4825** is a [protected sqlite3_value] object even if the input is not. 4826** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 4827** memory allocation fails. 4828** 4829** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 4830** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 4831** then sqlite3_value_free(V) is a harmless no-op. 4832*/ 4833sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 4834void sqlite3_value_free(sqlite3_value*); 4835 4836/* 4837** CAPI3REF: Obtain Aggregate Function Context 4838** METHOD: sqlite3_context 4839** 4840** Implementations of aggregate SQL functions use this 4841** routine to allocate memory for storing their state. 4842** 4843** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4844** for a particular aggregate function, SQLite 4845** allocates N of memory, zeroes out that memory, and returns a pointer 4846** to the new memory. ^On second and subsequent calls to 4847** sqlite3_aggregate_context() for the same aggregate function instance, 4848** the same buffer is returned. Sqlite3_aggregate_context() is normally 4849** called once for each invocation of the xStep callback and then one 4850** last time when the xFinal callback is invoked. ^(When no rows match 4851** an aggregate query, the xStep() callback of the aggregate function 4852** implementation is never called and xFinal() is called exactly once. 4853** In those cases, sqlite3_aggregate_context() might be called for the 4854** first time from within xFinal().)^ 4855** 4856** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4857** when first called if N is less than or equal to zero or if a memory 4858** allocate error occurs. 4859** 4860** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4861** determined by the N parameter on first successful call. Changing the 4862** value of N in subsequent call to sqlite3_aggregate_context() within 4863** the same aggregate function instance will not resize the memory 4864** allocation.)^ Within the xFinal callback, it is customary to set 4865** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4866** pointless memory allocations occur. 4867** 4868** ^SQLite automatically frees the memory allocated by 4869** sqlite3_aggregate_context() when the aggregate query concludes. 4870** 4871** The first parameter must be a copy of the 4872** [sqlite3_context | SQL function context] that is the first parameter 4873** to the xStep or xFinal callback routine that implements the aggregate 4874** function. 4875** 4876** This routine must be called from the same thread in which 4877** the aggregate SQL function is running. 4878*/ 4879void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4880 4881/* 4882** CAPI3REF: User Data For Functions 4883** METHOD: sqlite3_context 4884** 4885** ^The sqlite3_user_data() interface returns a copy of 4886** the pointer that was the pUserData parameter (the 5th parameter) 4887** of the [sqlite3_create_function()] 4888** and [sqlite3_create_function16()] routines that originally 4889** registered the application defined function. 4890** 4891** This routine must be called from the same thread in which 4892** the application-defined function is running. 4893*/ 4894void *sqlite3_user_data(sqlite3_context*); 4895 4896/* 4897** CAPI3REF: Database Connection For Functions 4898** METHOD: sqlite3_context 4899** 4900** ^The sqlite3_context_db_handle() interface returns a copy of 4901** the pointer to the [database connection] (the 1st parameter) 4902** of the [sqlite3_create_function()] 4903** and [sqlite3_create_function16()] routines that originally 4904** registered the application defined function. 4905*/ 4906sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4907 4908/* 4909** CAPI3REF: Function Auxiliary Data 4910** METHOD: sqlite3_context 4911** 4912** These functions may be used by (non-aggregate) SQL functions to 4913** associate metadata with argument values. If the same value is passed to 4914** multiple invocations of the same SQL function during query execution, under 4915** some circumstances the associated metadata may be preserved. An example 4916** of where this might be useful is in a regular-expression matching 4917** function. The compiled version of the regular expression can be stored as 4918** metadata associated with the pattern string. 4919** Then as long as the pattern string remains the same, 4920** the compiled regular expression can be reused on multiple 4921** invocations of the same function. 4922** 4923** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 4924** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 4925** value to the application-defined function. ^N is zero for the left-most 4926** function argument. ^If there is no metadata 4927** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 4928** returns a NULL pointer. 4929** 4930** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4931** argument of the application-defined function. ^Subsequent 4932** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4933** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4934** NULL if the metadata has been discarded. 4935** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4936** SQLite will invoke the destructor function X with parameter P exactly 4937** once, when the metadata is discarded. 4938** SQLite is free to discard the metadata at any time, including: <ul> 4939** <li> ^(when the corresponding function parameter changes)^, or 4940** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4941** SQL statement)^, or 4942** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 4943** parameter)^, or 4944** <li> ^(during the original sqlite3_set_auxdata() call when a memory 4945** allocation error occurs.)^ </ul> 4946** 4947** Note the last bullet in particular. The destructor X in 4948** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 4949** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 4950** should be called near the end of the function implementation and the 4951** function implementation should not make any use of P after 4952** sqlite3_set_auxdata() has been called. 4953** 4954** ^(In practice, metadata is preserved between function calls for 4955** function parameters that are compile-time constants, including literal 4956** values and [parameters] and expressions composed from the same.)^ 4957** 4958** The value of the N parameter to these interfaces should be non-negative. 4959** Future enhancements may make use of negative N values to define new 4960** kinds of function caching behavior. 4961** 4962** These routines must be called from the same thread in which 4963** the SQL function is running. 4964*/ 4965void *sqlite3_get_auxdata(sqlite3_context*, int N); 4966void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4967 4968 4969/* 4970** CAPI3REF: Constants Defining Special Destructor Behavior 4971** 4972** These are special values for the destructor that is passed in as the 4973** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4974** argument is SQLITE_STATIC, it means that the content pointer is constant 4975** and will never change. It does not need to be destroyed. ^The 4976** SQLITE_TRANSIENT value means that the content will likely change in 4977** the near future and that SQLite should make its own private copy of 4978** the content before returning. 4979** 4980** The typedef is necessary to work around problems in certain 4981** C++ compilers. 4982*/ 4983typedef void (*sqlite3_destructor_type)(void*); 4984#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4985#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4986 4987/* 4988** CAPI3REF: Setting The Result Of An SQL Function 4989** METHOD: sqlite3_context 4990** 4991** These routines are used by the xFunc or xFinal callbacks that 4992** implement SQL functions and aggregates. See 4993** [sqlite3_create_function()] and [sqlite3_create_function16()] 4994** for additional information. 4995** 4996** These functions work very much like the [parameter binding] family of 4997** functions used to bind values to host parameters in prepared statements. 4998** Refer to the [SQL parameter] documentation for additional information. 4999** 5000** ^The sqlite3_result_blob() interface sets the result from 5001** an application-defined function to be the BLOB whose content is pointed 5002** to by the second parameter and which is N bytes long where N is the 5003** third parameter. 5004** 5005** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5006** interfaces set the result of the application-defined function to be 5007** a BLOB containing all zero bytes and N bytes in size. 5008** 5009** ^The sqlite3_result_double() interface sets the result from 5010** an application-defined function to be a floating point value specified 5011** by its 2nd argument. 5012** 5013** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5014** cause the implemented SQL function to throw an exception. 5015** ^SQLite uses the string pointed to by the 5016** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5017** as the text of an error message. ^SQLite interprets the error 5018** message string from sqlite3_result_error() as UTF-8. ^SQLite 5019** interprets the string from sqlite3_result_error16() as UTF-16 in native 5020** byte order. ^If the third parameter to sqlite3_result_error() 5021** or sqlite3_result_error16() is negative then SQLite takes as the error 5022** message all text up through the first zero character. 5023** ^If the third parameter to sqlite3_result_error() or 5024** sqlite3_result_error16() is non-negative then SQLite takes that many 5025** bytes (not characters) from the 2nd parameter as the error message. 5026** ^The sqlite3_result_error() and sqlite3_result_error16() 5027** routines make a private copy of the error message text before 5028** they return. Hence, the calling function can deallocate or 5029** modify the text after they return without harm. 5030** ^The sqlite3_result_error_code() function changes the error code 5031** returned by SQLite as a result of an error in a function. ^By default, 5032** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5033** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5034** 5035** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5036** error indicating that a string or BLOB is too long to represent. 5037** 5038** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5039** error indicating that a memory allocation failed. 5040** 5041** ^The sqlite3_result_int() interface sets the return value 5042** of the application-defined function to be the 32-bit signed integer 5043** value given in the 2nd argument. 5044** ^The sqlite3_result_int64() interface sets the return value 5045** of the application-defined function to be the 64-bit signed integer 5046** value given in the 2nd argument. 5047** 5048** ^The sqlite3_result_null() interface sets the return value 5049** of the application-defined function to be NULL. 5050** 5051** ^The sqlite3_result_text(), sqlite3_result_text16(), 5052** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5053** set the return value of the application-defined function to be 5054** a text string which is represented as UTF-8, UTF-16 native byte order, 5055** UTF-16 little endian, or UTF-16 big endian, respectively. 5056** ^The sqlite3_result_text64() interface sets the return value of an 5057** application-defined function to be a text string in an encoding 5058** specified by the fifth (and last) parameter, which must be one 5059** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5060** ^SQLite takes the text result from the application from 5061** the 2nd parameter of the sqlite3_result_text* interfaces. 5062** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5063** is negative, then SQLite takes result text from the 2nd parameter 5064** through the first zero character. 5065** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5066** is non-negative, then as many bytes (not characters) of the text 5067** pointed to by the 2nd parameter are taken as the application-defined 5068** function result. If the 3rd parameter is non-negative, then it 5069** must be the byte offset into the string where the NUL terminator would 5070** appear if the string where NUL terminated. If any NUL characters occur 5071** in the string at a byte offset that is less than the value of the 3rd 5072** parameter, then the resulting string will contain embedded NULs and the 5073** result of expressions operating on strings with embedded NULs is undefined. 5074** ^If the 4th parameter to the sqlite3_result_text* interfaces 5075** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5076** function as the destructor on the text or BLOB result when it has 5077** finished using that result. 5078** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5079** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5080** assumes that the text or BLOB result is in constant space and does not 5081** copy the content of the parameter nor call a destructor on the content 5082** when it has finished using that result. 5083** ^If the 4th parameter to the sqlite3_result_text* interfaces 5084** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5085** then SQLite makes a copy of the result into space obtained 5086** from [sqlite3_malloc()] before it returns. 5087** 5088** ^The sqlite3_result_value() interface sets the result of 5089** the application-defined function to be a copy of the 5090** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5091** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5092** so that the [sqlite3_value] specified in the parameter may change or 5093** be deallocated after sqlite3_result_value() returns without harm. 5094** ^A [protected sqlite3_value] object may always be used where an 5095** [unprotected sqlite3_value] object is required, so either 5096** kind of [sqlite3_value] object can be used with this interface. 5097** 5098** ^The sqlite3_result_pointer(C,P) interface sets the result to an 5099** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5100** also associates the host-language pointer P with that NULL value such 5101** that the pointer can be retrieved within an 5102** [application-defined SQL function] using [sqlite3_value_pointer()]. 5103** This mechanism can be used to pass non-SQL values between 5104** application-defined functions. 5105** 5106** If these routines are called from within the different thread 5107** than the one containing the application-defined function that received 5108** the [sqlite3_context] pointer, the results are undefined. 5109*/ 5110void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5111void sqlite3_result_blob64(sqlite3_context*,const void*, 5112 sqlite3_uint64,void(*)(void*)); 5113void sqlite3_result_double(sqlite3_context*, double); 5114void sqlite3_result_error(sqlite3_context*, const char*, int); 5115void sqlite3_result_error16(sqlite3_context*, const void*, int); 5116void sqlite3_result_error_toobig(sqlite3_context*); 5117void sqlite3_result_error_nomem(sqlite3_context*); 5118void sqlite3_result_error_code(sqlite3_context*, int); 5119void sqlite3_result_int(sqlite3_context*, int); 5120void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5121void sqlite3_result_null(sqlite3_context*); 5122void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5123void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5124 void(*)(void*), unsigned char encoding); 5125void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5126void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5127void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5128void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5129void sqlite3_result_pointer(sqlite3_context*, void*); 5130void sqlite3_result_zeroblob(sqlite3_context*, int n); 5131int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5132 5133 5134/* 5135** CAPI3REF: Setting The Subtype Of An SQL Function 5136** METHOD: sqlite3_context 5137** 5138** The sqlite3_result_subtype(C,T) function causes the subtype of 5139** the result from the [application-defined SQL function] with 5140** [sqlite3_context] C to be the value T. Only the lower 8 bits 5141** of the subtype T are preserved in current versions of SQLite; 5142** higher order bits are discarded. 5143** The number of subtype bytes preserved by SQLite might increase 5144** in future releases of SQLite. 5145*/ 5146void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5147 5148/* 5149** CAPI3REF: Define New Collating Sequences 5150** METHOD: sqlite3 5151** 5152** ^These functions add, remove, or modify a [collation] associated 5153** with the [database connection] specified as the first argument. 5154** 5155** ^The name of the collation is a UTF-8 string 5156** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5157** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5158** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5159** considered to be the same name. 5160** 5161** ^(The third argument (eTextRep) must be one of the constants: 5162** <ul> 5163** <li> [SQLITE_UTF8], 5164** <li> [SQLITE_UTF16LE], 5165** <li> [SQLITE_UTF16BE], 5166** <li> [SQLITE_UTF16], or 5167** <li> [SQLITE_UTF16_ALIGNED]. 5168** </ul>)^ 5169** ^The eTextRep argument determines the encoding of strings passed 5170** to the collating function callback, xCallback. 5171** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5172** force strings to be UTF16 with native byte order. 5173** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5174** on an even byte address. 5175** 5176** ^The fourth argument, pArg, is an application data pointer that is passed 5177** through as the first argument to the collating function callback. 5178** 5179** ^The fifth argument, xCallback, is a pointer to the collating function. 5180** ^Multiple collating functions can be registered using the same name but 5181** with different eTextRep parameters and SQLite will use whichever 5182** function requires the least amount of data transformation. 5183** ^If the xCallback argument is NULL then the collating function is 5184** deleted. ^When all collating functions having the same name are deleted, 5185** that collation is no longer usable. 5186** 5187** ^The collating function callback is invoked with a copy of the pArg 5188** application data pointer and with two strings in the encoding specified 5189** by the eTextRep argument. The collating function must return an 5190** integer that is negative, zero, or positive 5191** if the first string is less than, equal to, or greater than the second, 5192** respectively. A collating function must always return the same answer 5193** given the same inputs. If two or more collating functions are registered 5194** to the same collation name (using different eTextRep values) then all 5195** must give an equivalent answer when invoked with equivalent strings. 5196** The collating function must obey the following properties for all 5197** strings A, B, and C: 5198** 5199** <ol> 5200** <li> If A==B then B==A. 5201** <li> If A==B and B==C then A==C. 5202** <li> If A<B THEN B>A. 5203** <li> If A<B and B<C then A<C. 5204** </ol> 5205** 5206** If a collating function fails any of the above constraints and that 5207** collating function is registered and used, then the behavior of SQLite 5208** is undefined. 5209** 5210** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5211** with the addition that the xDestroy callback is invoked on pArg when 5212** the collating function is deleted. 5213** ^Collating functions are deleted when they are overridden by later 5214** calls to the collation creation functions or when the 5215** [database connection] is closed using [sqlite3_close()]. 5216** 5217** ^The xDestroy callback is <u>not</u> called if the 5218** sqlite3_create_collation_v2() function fails. Applications that invoke 5219** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5220** check the return code and dispose of the application data pointer 5221** themselves rather than expecting SQLite to deal with it for them. 5222** This is different from every other SQLite interface. The inconsistency 5223** is unfortunate but cannot be changed without breaking backwards 5224** compatibility. 5225** 5226** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5227*/ 5228int sqlite3_create_collation( 5229 sqlite3*, 5230 const char *zName, 5231 int eTextRep, 5232 void *pArg, 5233 int(*xCompare)(void*,int,const void*,int,const void*) 5234); 5235int sqlite3_create_collation_v2( 5236 sqlite3*, 5237 const char *zName, 5238 int eTextRep, 5239 void *pArg, 5240 int(*xCompare)(void*,int,const void*,int,const void*), 5241 void(*xDestroy)(void*) 5242); 5243int sqlite3_create_collation16( 5244 sqlite3*, 5245 const void *zName, 5246 int eTextRep, 5247 void *pArg, 5248 int(*xCompare)(void*,int,const void*,int,const void*) 5249); 5250 5251/* 5252** CAPI3REF: Collation Needed Callbacks 5253** METHOD: sqlite3 5254** 5255** ^To avoid having to register all collation sequences before a database 5256** can be used, a single callback function may be registered with the 5257** [database connection] to be invoked whenever an undefined collation 5258** sequence is required. 5259** 5260** ^If the function is registered using the sqlite3_collation_needed() API, 5261** then it is passed the names of undefined collation sequences as strings 5262** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5263** the names are passed as UTF-16 in machine native byte order. 5264** ^A call to either function replaces the existing collation-needed callback. 5265** 5266** ^(When the callback is invoked, the first argument passed is a copy 5267** of the second argument to sqlite3_collation_needed() or 5268** sqlite3_collation_needed16(). The second argument is the database 5269** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5270** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5271** sequence function required. The fourth parameter is the name of the 5272** required collation sequence.)^ 5273** 5274** The callback function should register the desired collation using 5275** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5276** [sqlite3_create_collation_v2()]. 5277*/ 5278int sqlite3_collation_needed( 5279 sqlite3*, 5280 void*, 5281 void(*)(void*,sqlite3*,int eTextRep,const char*) 5282); 5283int sqlite3_collation_needed16( 5284 sqlite3*, 5285 void*, 5286 void(*)(void*,sqlite3*,int eTextRep,const void*) 5287); 5288 5289#ifdef SQLITE_HAS_CODEC 5290/* 5291** Specify the key for an encrypted database. This routine should be 5292** called right after sqlite3_open(). 5293** 5294** The code to implement this API is not available in the public release 5295** of SQLite. 5296*/ 5297int sqlite3_key( 5298 sqlite3 *db, /* Database to be rekeyed */ 5299 const void *pKey, int nKey /* The key */ 5300); 5301int sqlite3_key_v2( 5302 sqlite3 *db, /* Database to be rekeyed */ 5303 const char *zDbName, /* Name of the database */ 5304 const void *pKey, int nKey /* The key */ 5305); 5306 5307/* 5308** Change the key on an open database. If the current database is not 5309** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 5310** database is decrypted. 5311** 5312** The code to implement this API is not available in the public release 5313** of SQLite. 5314*/ 5315int sqlite3_rekey( 5316 sqlite3 *db, /* Database to be rekeyed */ 5317 const void *pKey, int nKey /* The new key */ 5318); 5319int sqlite3_rekey_v2( 5320 sqlite3 *db, /* Database to be rekeyed */ 5321 const char *zDbName, /* Name of the database */ 5322 const void *pKey, int nKey /* The new key */ 5323); 5324 5325/* 5326** Specify the activation key for a SEE database. Unless 5327** activated, none of the SEE routines will work. 5328*/ 5329void sqlite3_activate_see( 5330 const char *zPassPhrase /* Activation phrase */ 5331); 5332#endif 5333 5334#ifdef SQLITE_ENABLE_CEROD 5335/* 5336** Specify the activation key for a CEROD database. Unless 5337** activated, none of the CEROD routines will work. 5338*/ 5339void sqlite3_activate_cerod( 5340 const char *zPassPhrase /* Activation phrase */ 5341); 5342#endif 5343 5344/* 5345** CAPI3REF: Suspend Execution For A Short Time 5346** 5347** The sqlite3_sleep() function causes the current thread to suspend execution 5348** for at least a number of milliseconds specified in its parameter. 5349** 5350** If the operating system does not support sleep requests with 5351** millisecond time resolution, then the time will be rounded up to 5352** the nearest second. The number of milliseconds of sleep actually 5353** requested from the operating system is returned. 5354** 5355** ^SQLite implements this interface by calling the xSleep() 5356** method of the default [sqlite3_vfs] object. If the xSleep() method 5357** of the default VFS is not implemented correctly, or not implemented at 5358** all, then the behavior of sqlite3_sleep() may deviate from the description 5359** in the previous paragraphs. 5360*/ 5361int sqlite3_sleep(int); 5362 5363/* 5364** CAPI3REF: Name Of The Folder Holding Temporary Files 5365** 5366** ^(If this global variable is made to point to a string which is 5367** the name of a folder (a.k.a. directory), then all temporary files 5368** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5369** will be placed in that directory.)^ ^If this variable 5370** is a NULL pointer, then SQLite performs a search for an appropriate 5371** temporary file directory. 5372** 5373** Applications are strongly discouraged from using this global variable. 5374** It is required to set a temporary folder on Windows Runtime (WinRT). 5375** But for all other platforms, it is highly recommended that applications 5376** neither read nor write this variable. This global variable is a relic 5377** that exists for backwards compatibility of legacy applications and should 5378** be avoided in new projects. 5379** 5380** It is not safe to read or modify this variable in more than one 5381** thread at a time. It is not safe to read or modify this variable 5382** if a [database connection] is being used at the same time in a separate 5383** thread. 5384** It is intended that this variable be set once 5385** as part of process initialization and before any SQLite interface 5386** routines have been called and that this variable remain unchanged 5387** thereafter. 5388** 5389** ^The [temp_store_directory pragma] may modify this variable and cause 5390** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5391** the [temp_store_directory pragma] always assumes that any string 5392** that this variable points to is held in memory obtained from 5393** [sqlite3_malloc] and the pragma may attempt to free that memory 5394** using [sqlite3_free]. 5395** Hence, if this variable is modified directly, either it should be 5396** made NULL or made to point to memory obtained from [sqlite3_malloc] 5397** or else the use of the [temp_store_directory pragma] should be avoided. 5398** Except when requested by the [temp_store_directory pragma], SQLite 5399** does not free the memory that sqlite3_temp_directory points to. If 5400** the application wants that memory to be freed, it must do 5401** so itself, taking care to only do so after all [database connection] 5402** objects have been destroyed. 5403** 5404** <b>Note to Windows Runtime users:</b> The temporary directory must be set 5405** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 5406** features that require the use of temporary files may fail. Here is an 5407** example of how to do this using C++ with the Windows Runtime: 5408** 5409** <blockquote><pre> 5410** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 5411** TemporaryFolder->Path->Data(); 5412** char zPathBuf[MAX_PATH + 1]; 5413** memset(zPathBuf, 0, sizeof(zPathBuf)); 5414** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 5415** NULL, NULL); 5416** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 5417** </pre></blockquote> 5418*/ 5419SQLITE_EXTERN char *sqlite3_temp_directory; 5420 5421/* 5422** CAPI3REF: Name Of The Folder Holding Database Files 5423** 5424** ^(If this global variable is made to point to a string which is 5425** the name of a folder (a.k.a. directory), then all database files 5426** specified with a relative pathname and created or accessed by 5427** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 5428** to be relative to that directory.)^ ^If this variable is a NULL 5429** pointer, then SQLite assumes that all database files specified 5430** with a relative pathname are relative to the current directory 5431** for the process. Only the windows VFS makes use of this global 5432** variable; it is ignored by the unix VFS. 5433** 5434** Changing the value of this variable while a database connection is 5435** open can result in a corrupt database. 5436** 5437** It is not safe to read or modify this variable in more than one 5438** thread at a time. It is not safe to read or modify this variable 5439** if a [database connection] is being used at the same time in a separate 5440** thread. 5441** It is intended that this variable be set once 5442** as part of process initialization and before any SQLite interface 5443** routines have been called and that this variable remain unchanged 5444** thereafter. 5445** 5446** ^The [data_store_directory pragma] may modify this variable and cause 5447** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5448** the [data_store_directory pragma] always assumes that any string 5449** that this variable points to is held in memory obtained from 5450** [sqlite3_malloc] and the pragma may attempt to free that memory 5451** using [sqlite3_free]. 5452** Hence, if this variable is modified directly, either it should be 5453** made NULL or made to point to memory obtained from [sqlite3_malloc] 5454** or else the use of the [data_store_directory pragma] should be avoided. 5455*/ 5456SQLITE_EXTERN char *sqlite3_data_directory; 5457 5458/* 5459** CAPI3REF: Test For Auto-Commit Mode 5460** KEYWORDS: {autocommit mode} 5461** METHOD: sqlite3 5462** 5463** ^The sqlite3_get_autocommit() interface returns non-zero or 5464** zero if the given database connection is or is not in autocommit mode, 5465** respectively. ^Autocommit mode is on by default. 5466** ^Autocommit mode is disabled by a [BEGIN] statement. 5467** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5468** 5469** If certain kinds of errors occur on a statement within a multi-statement 5470** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5471** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5472** transaction might be rolled back automatically. The only way to 5473** find out whether SQLite automatically rolled back the transaction after 5474** an error is to use this function. 5475** 5476** If another thread changes the autocommit status of the database 5477** connection while this routine is running, then the return value 5478** is undefined. 5479*/ 5480int sqlite3_get_autocommit(sqlite3*); 5481 5482/* 5483** CAPI3REF: Find The Database Handle Of A Prepared Statement 5484** METHOD: sqlite3_stmt 5485** 5486** ^The sqlite3_db_handle interface returns the [database connection] handle 5487** to which a [prepared statement] belongs. ^The [database connection] 5488** returned by sqlite3_db_handle is the same [database connection] 5489** that was the first argument 5490** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5491** create the statement in the first place. 5492*/ 5493sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5494 5495/* 5496** CAPI3REF: Return The Filename For A Database Connection 5497** METHOD: sqlite3 5498** 5499** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5500** associated with database N of connection D. ^The main database file 5501** has the name "main". If there is no attached database N on the database 5502** connection D, or if database N is a temporary or in-memory database, then 5503** a NULL pointer is returned. 5504** 5505** ^The filename returned by this function is the output of the 5506** xFullPathname method of the [VFS]. ^In other words, the filename 5507** will be an absolute pathname, even if the filename used 5508** to open the database originally was a URI or relative pathname. 5509*/ 5510const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5511 5512/* 5513** CAPI3REF: Determine if a database is read-only 5514** METHOD: sqlite3 5515** 5516** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5517** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5518** the name of a database on connection D. 5519*/ 5520int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5521 5522/* 5523** CAPI3REF: Find the next prepared statement 5524** METHOD: sqlite3 5525** 5526** ^This interface returns a pointer to the next [prepared statement] after 5527** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5528** then this interface returns a pointer to the first prepared statement 5529** associated with the database connection pDb. ^If no prepared statement 5530** satisfies the conditions of this routine, it returns NULL. 5531** 5532** The [database connection] pointer D in a call to 5533** [sqlite3_next_stmt(D,S)] must refer to an open database 5534** connection and in particular must not be a NULL pointer. 5535*/ 5536sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5537 5538/* 5539** CAPI3REF: Commit And Rollback Notification Callbacks 5540** METHOD: sqlite3 5541** 5542** ^The sqlite3_commit_hook() interface registers a callback 5543** function to be invoked whenever a transaction is [COMMIT | committed]. 5544** ^Any callback set by a previous call to sqlite3_commit_hook() 5545** for the same database connection is overridden. 5546** ^The sqlite3_rollback_hook() interface registers a callback 5547** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5548** ^Any callback set by a previous call to sqlite3_rollback_hook() 5549** for the same database connection is overridden. 5550** ^The pArg argument is passed through to the callback. 5551** ^If the callback on a commit hook function returns non-zero, 5552** then the commit is converted into a rollback. 5553** 5554** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5555** return the P argument from the previous call of the same function 5556** on the same [database connection] D, or NULL for 5557** the first call for each function on D. 5558** 5559** The commit and rollback hook callbacks are not reentrant. 5560** The callback implementation must not do anything that will modify 5561** the database connection that invoked the callback. Any actions 5562** to modify the database connection must be deferred until after the 5563** completion of the [sqlite3_step()] call that triggered the commit 5564** or rollback hook in the first place. 5565** Note that running any other SQL statements, including SELECT statements, 5566** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5567** the database connections for the meaning of "modify" in this paragraph. 5568** 5569** ^Registering a NULL function disables the callback. 5570** 5571** ^When the commit hook callback routine returns zero, the [COMMIT] 5572** operation is allowed to continue normally. ^If the commit hook 5573** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5574** ^The rollback hook is invoked on a rollback that results from a commit 5575** hook returning non-zero, just as it would be with any other rollback. 5576** 5577** ^For the purposes of this API, a transaction is said to have been 5578** rolled back if an explicit "ROLLBACK" statement is executed, or 5579** an error or constraint causes an implicit rollback to occur. 5580** ^The rollback callback is not invoked if a transaction is 5581** automatically rolled back because the database connection is closed. 5582** 5583** See also the [sqlite3_update_hook()] interface. 5584*/ 5585void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5586void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5587 5588/* 5589** CAPI3REF: Data Change Notification Callbacks 5590** METHOD: sqlite3 5591** 5592** ^The sqlite3_update_hook() interface registers a callback function 5593** with the [database connection] identified by the first argument 5594** to be invoked whenever a row is updated, inserted or deleted in 5595** a [rowid table]. 5596** ^Any callback set by a previous call to this function 5597** for the same database connection is overridden. 5598** 5599** ^The second argument is a pointer to the function to invoke when a 5600** row is updated, inserted or deleted in a rowid table. 5601** ^The first argument to the callback is a copy of the third argument 5602** to sqlite3_update_hook(). 5603** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5604** or [SQLITE_UPDATE], depending on the operation that caused the callback 5605** to be invoked. 5606** ^The third and fourth arguments to the callback contain pointers to the 5607** database and table name containing the affected row. 5608** ^The final callback parameter is the [rowid] of the row. 5609** ^In the case of an update, this is the [rowid] after the update takes place. 5610** 5611** ^(The update hook is not invoked when internal system tables are 5612** modified (i.e. sqlite_master and sqlite_sequence).)^ 5613** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5614** 5615** ^In the current implementation, the update hook 5616** is not invoked when conflicting rows are deleted because of an 5617** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5618** invoked when rows are deleted using the [truncate optimization]. 5619** The exceptions defined in this paragraph might change in a future 5620** release of SQLite. 5621** 5622** The update hook implementation must not do anything that will modify 5623** the database connection that invoked the update hook. Any actions 5624** to modify the database connection must be deferred until after the 5625** completion of the [sqlite3_step()] call that triggered the update hook. 5626** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5627** database connections for the meaning of "modify" in this paragraph. 5628** 5629** ^The sqlite3_update_hook(D,C,P) function 5630** returns the P argument from the previous call 5631** on the same [database connection] D, or NULL for 5632** the first call on D. 5633** 5634** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 5635** and [sqlite3_preupdate_hook()] interfaces. 5636*/ 5637void *sqlite3_update_hook( 5638 sqlite3*, 5639 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5640 void* 5641); 5642 5643/* 5644** CAPI3REF: Enable Or Disable Shared Pager Cache 5645** 5646** ^(This routine enables or disables the sharing of the database cache 5647** and schema data structures between [database connection | connections] 5648** to the same database. Sharing is enabled if the argument is true 5649** and disabled if the argument is false.)^ 5650** 5651** ^Cache sharing is enabled and disabled for an entire process. 5652** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 5653** In prior versions of SQLite, 5654** sharing was enabled or disabled for each thread separately. 5655** 5656** ^(The cache sharing mode set by this interface effects all subsequent 5657** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5658** Existing database connections continue use the sharing mode 5659** that was in effect at the time they were opened.)^ 5660** 5661** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5662** successfully. An [error code] is returned otherwise.)^ 5663** 5664** ^Shared cache is disabled by default. But this might change in 5665** future releases of SQLite. Applications that care about shared 5666** cache setting should set it explicitly. 5667** 5668** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5669** and will always return SQLITE_MISUSE. On those systems, 5670** shared cache mode should be enabled per-database connection via 5671** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5672** 5673** This interface is threadsafe on processors where writing a 5674** 32-bit integer is atomic. 5675** 5676** See Also: [SQLite Shared-Cache Mode] 5677*/ 5678int sqlite3_enable_shared_cache(int); 5679 5680/* 5681** CAPI3REF: Attempt To Free Heap Memory 5682** 5683** ^The sqlite3_release_memory() interface attempts to free N bytes 5684** of heap memory by deallocating non-essential memory allocations 5685** held by the database library. Memory used to cache database 5686** pages to improve performance is an example of non-essential memory. 5687** ^sqlite3_release_memory() returns the number of bytes actually freed, 5688** which might be more or less than the amount requested. 5689** ^The sqlite3_release_memory() routine is a no-op returning zero 5690** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5691** 5692** See also: [sqlite3_db_release_memory()] 5693*/ 5694int sqlite3_release_memory(int); 5695 5696/* 5697** CAPI3REF: Free Memory Used By A Database Connection 5698** METHOD: sqlite3 5699** 5700** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5701** memory as possible from database connection D. Unlike the 5702** [sqlite3_release_memory()] interface, this interface is in effect even 5703** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5704** omitted. 5705** 5706** See also: [sqlite3_release_memory()] 5707*/ 5708int sqlite3_db_release_memory(sqlite3*); 5709 5710/* 5711** CAPI3REF: Impose A Limit On Heap Size 5712** 5713** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5714** soft limit on the amount of heap memory that may be allocated by SQLite. 5715** ^SQLite strives to keep heap memory utilization below the soft heap 5716** limit by reducing the number of pages held in the page cache 5717** as heap memory usages approaches the limit. 5718** ^The soft heap limit is "soft" because even though SQLite strives to stay 5719** below the limit, it will exceed the limit rather than generate 5720** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5721** is advisory only. 5722** 5723** ^The return value from sqlite3_soft_heap_limit64() is the size of 5724** the soft heap limit prior to the call, or negative in the case of an 5725** error. ^If the argument N is negative 5726** then no change is made to the soft heap limit. Hence, the current 5727** size of the soft heap limit can be determined by invoking 5728** sqlite3_soft_heap_limit64() with a negative argument. 5729** 5730** ^If the argument N is zero then the soft heap limit is disabled. 5731** 5732** ^(The soft heap limit is not enforced in the current implementation 5733** if one or more of following conditions are true: 5734** 5735** <ul> 5736** <li> The soft heap limit is set to zero. 5737** <li> Memory accounting is disabled using a combination of the 5738** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5739** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5740** <li> An alternative page cache implementation is specified using 5741** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5742** <li> The page cache allocates from its own memory pool supplied 5743** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5744** from the heap. 5745** </ul>)^ 5746** 5747** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]), 5748** the soft heap limit is enforced 5749** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5750** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5751** the soft heap limit is enforced on every memory allocation. Without 5752** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5753** when memory is allocated by the page cache. Testing suggests that because 5754** the page cache is the predominate memory user in SQLite, most 5755** applications will achieve adequate soft heap limit enforcement without 5756** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5757** 5758** The circumstances under which SQLite will enforce the soft heap limit may 5759** changes in future releases of SQLite. 5760*/ 5761sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5762 5763/* 5764** CAPI3REF: Deprecated Soft Heap Limit Interface 5765** DEPRECATED 5766** 5767** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5768** interface. This routine is provided for historical compatibility 5769** only. All new applications should use the 5770** [sqlite3_soft_heap_limit64()] interface rather than this one. 5771*/ 5772SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5773 5774 5775/* 5776** CAPI3REF: Extract Metadata About A Column Of A Table 5777** METHOD: sqlite3 5778** 5779** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5780** information about column C of table T in database D 5781** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5782** interface returns SQLITE_OK and fills in the non-NULL pointers in 5783** the final five arguments with appropriate values if the specified 5784** column exists. ^The sqlite3_table_column_metadata() interface returns 5785** SQLITE_ERROR and if the specified column does not exist. 5786** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5787** NULL pointer, then this routine simply checks for the existence of the 5788** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5789** does not. If the table name parameter T in a call to 5790** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 5791** undefined behavior. 5792** 5793** ^The column is identified by the second, third and fourth parameters to 5794** this function. ^(The second parameter is either the name of the database 5795** (i.e. "main", "temp", or an attached database) containing the specified 5796** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5797** for the table using the same algorithm used by the database engine to 5798** resolve unqualified table references. 5799** 5800** ^The third and fourth parameters to this function are the table and column 5801** name of the desired column, respectively. 5802** 5803** ^Metadata is returned by writing to the memory locations passed as the 5th 5804** and subsequent parameters to this function. ^Any of these arguments may be 5805** NULL, in which case the corresponding element of metadata is omitted. 5806** 5807** ^(<blockquote> 5808** <table border="1"> 5809** <tr><th> Parameter <th> Output<br>Type <th> Description 5810** 5811** <tr><td> 5th <td> const char* <td> Data type 5812** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5813** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5814** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5815** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5816** </table> 5817** </blockquote>)^ 5818** 5819** ^The memory pointed to by the character pointers returned for the 5820** declaration type and collation sequence is valid until the next 5821** call to any SQLite API function. 5822** 5823** ^If the specified table is actually a view, an [error code] is returned. 5824** 5825** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5826** is not a [WITHOUT ROWID] table and an 5827** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5828** parameters are set for the explicitly declared column. ^(If there is no 5829** [INTEGER PRIMARY KEY] column, then the outputs 5830** for the [rowid] are set as follows: 5831** 5832** <pre> 5833** data type: "INTEGER" 5834** collation sequence: "BINARY" 5835** not null: 0 5836** primary key: 1 5837** auto increment: 0 5838** </pre>)^ 5839** 5840** ^This function causes all database schemas to be read from disk and 5841** parsed, if that has not already been done, and returns an error if 5842** any errors are encountered while loading the schema. 5843*/ 5844int sqlite3_table_column_metadata( 5845 sqlite3 *db, /* Connection handle */ 5846 const char *zDbName, /* Database name or NULL */ 5847 const char *zTableName, /* Table name */ 5848 const char *zColumnName, /* Column name */ 5849 char const **pzDataType, /* OUTPUT: Declared data type */ 5850 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5851 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5852 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5853 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5854); 5855 5856/* 5857** CAPI3REF: Load An Extension 5858** METHOD: sqlite3 5859** 5860** ^This interface loads an SQLite extension library from the named file. 5861** 5862** ^The sqlite3_load_extension() interface attempts to load an 5863** [SQLite extension] library contained in the file zFile. If 5864** the file cannot be loaded directly, attempts are made to load 5865** with various operating-system specific extensions added. 5866** So for example, if "samplelib" cannot be loaded, then names like 5867** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5868** be tried also. 5869** 5870** ^The entry point is zProc. 5871** ^(zProc may be 0, in which case SQLite will try to come up with an 5872** entry point name on its own. It first tries "sqlite3_extension_init". 5873** If that does not work, it constructs a name "sqlite3_X_init" where the 5874** X is consists of the lower-case equivalent of all ASCII alphabetic 5875** characters in the filename from the last "/" to the first following 5876** "." and omitting any initial "lib".)^ 5877** ^The sqlite3_load_extension() interface returns 5878** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5879** ^If an error occurs and pzErrMsg is not 0, then the 5880** [sqlite3_load_extension()] interface shall attempt to 5881** fill *pzErrMsg with error message text stored in memory 5882** obtained from [sqlite3_malloc()]. The calling function 5883** should free this memory by calling [sqlite3_free()]. 5884** 5885** ^Extension loading must be enabled using 5886** [sqlite3_enable_load_extension()] or 5887** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 5888** prior to calling this API, 5889** otherwise an error will be returned. 5890** 5891** <b>Security warning:</b> It is recommended that the 5892** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 5893** interface. The use of the [sqlite3_enable_load_extension()] interface 5894** should be avoided. This will keep the SQL function [load_extension()] 5895** disabled and prevent SQL injections from giving attackers 5896** access to extension loading capabilities. 5897** 5898** See also the [load_extension() SQL function]. 5899*/ 5900int sqlite3_load_extension( 5901 sqlite3 *db, /* Load the extension into this database connection */ 5902 const char *zFile, /* Name of the shared library containing extension */ 5903 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5904 char **pzErrMsg /* Put error message here if not 0 */ 5905); 5906 5907/* 5908** CAPI3REF: Enable Or Disable Extension Loading 5909** METHOD: sqlite3 5910** 5911** ^So as not to open security holes in older applications that are 5912** unprepared to deal with [extension loading], and as a means of disabling 5913** [extension loading] while evaluating user-entered SQL, the following API 5914** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5915** 5916** ^Extension loading is off by default. 5917** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5918** to turn extension loading on and call it with onoff==0 to turn 5919** it back off again. 5920** 5921** ^This interface enables or disables both the C-API 5922** [sqlite3_load_extension()] and the SQL function [load_extension()]. 5923** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 5924** to enable or disable only the C-API.)^ 5925** 5926** <b>Security warning:</b> It is recommended that extension loading 5927** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 5928** rather than this interface, so the [load_extension()] SQL function 5929** remains disabled. This will prevent SQL injections from giving attackers 5930** access to extension loading capabilities. 5931*/ 5932int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5933 5934/* 5935** CAPI3REF: Automatically Load Statically Linked Extensions 5936** 5937** ^This interface causes the xEntryPoint() function to be invoked for 5938** each new [database connection] that is created. The idea here is that 5939** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5940** that is to be automatically loaded into all new database connections. 5941** 5942** ^(Even though the function prototype shows that xEntryPoint() takes 5943** no arguments and returns void, SQLite invokes xEntryPoint() with three 5944** arguments and expects an integer result as if the signature of the 5945** entry point where as follows: 5946** 5947** <blockquote><pre> 5948** int xEntryPoint( 5949** sqlite3 *db, 5950** const char **pzErrMsg, 5951** const struct sqlite3_api_routines *pThunk 5952** ); 5953** </pre></blockquote>)^ 5954** 5955** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5956** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5957** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5958** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5959** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5960** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5961** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 5962** 5963** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 5964** on the list of automatic extensions is a harmless no-op. ^No entry point 5965** will be called more than once for each database connection that is opened. 5966** 5967** See also: [sqlite3_reset_auto_extension()] 5968** and [sqlite3_cancel_auto_extension()] 5969*/ 5970int sqlite3_auto_extension(void(*xEntryPoint)(void)); 5971 5972/* 5973** CAPI3REF: Cancel Automatic Extension Loading 5974** 5975** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 5976** initialization routine X that was registered using a prior call to 5977** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 5978** routine returns 1 if initialization routine X was successfully 5979** unregistered and it returns 0 if X was not on the list of initialization 5980** routines. 5981*/ 5982int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 5983 5984/* 5985** CAPI3REF: Reset Automatic Extension Loading 5986** 5987** ^This interface disables all automatic extensions previously 5988** registered using [sqlite3_auto_extension()]. 5989*/ 5990void sqlite3_reset_auto_extension(void); 5991 5992/* 5993** The interface to the virtual-table mechanism is currently considered 5994** to be experimental. The interface might change in incompatible ways. 5995** If this is a problem for you, do not use the interface at this time. 5996** 5997** When the virtual-table mechanism stabilizes, we will declare the 5998** interface fixed, support it indefinitely, and remove this comment. 5999*/ 6000 6001/* 6002** Structures used by the virtual table interface 6003*/ 6004typedef struct sqlite3_vtab sqlite3_vtab; 6005typedef struct sqlite3_index_info sqlite3_index_info; 6006typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6007typedef struct sqlite3_module sqlite3_module; 6008 6009/* 6010** CAPI3REF: Virtual Table Object 6011** KEYWORDS: sqlite3_module {virtual table module} 6012** 6013** This structure, sometimes called a "virtual table module", 6014** defines the implementation of a [virtual tables]. 6015** This structure consists mostly of methods for the module. 6016** 6017** ^A virtual table module is created by filling in a persistent 6018** instance of this structure and passing a pointer to that instance 6019** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6020** ^The registration remains valid until it is replaced by a different 6021** module or until the [database connection] closes. The content 6022** of this structure must not change while it is registered with 6023** any database connection. 6024*/ 6025struct sqlite3_module { 6026 int iVersion; 6027 int (*xCreate)(sqlite3*, void *pAux, 6028 int argc, const char *const*argv, 6029 sqlite3_vtab **ppVTab, char**); 6030 int (*xConnect)(sqlite3*, void *pAux, 6031 int argc, const char *const*argv, 6032 sqlite3_vtab **ppVTab, char**); 6033 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6034 int (*xDisconnect)(sqlite3_vtab *pVTab); 6035 int (*xDestroy)(sqlite3_vtab *pVTab); 6036 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6037 int (*xClose)(sqlite3_vtab_cursor*); 6038 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6039 int argc, sqlite3_value **argv); 6040 int (*xNext)(sqlite3_vtab_cursor*); 6041 int (*xEof)(sqlite3_vtab_cursor*); 6042 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6043 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6044 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6045 int (*xBegin)(sqlite3_vtab *pVTab); 6046 int (*xSync)(sqlite3_vtab *pVTab); 6047 int (*xCommit)(sqlite3_vtab *pVTab); 6048 int (*xRollback)(sqlite3_vtab *pVTab); 6049 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6050 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6051 void **ppArg); 6052 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6053 /* The methods above are in version 1 of the sqlite_module object. Those 6054 ** below are for version 2 and greater. */ 6055 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6056 int (*xRelease)(sqlite3_vtab *pVTab, int); 6057 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6058}; 6059 6060/* 6061** CAPI3REF: Virtual Table Indexing Information 6062** KEYWORDS: sqlite3_index_info 6063** 6064** The sqlite3_index_info structure and its substructures is used as part 6065** of the [virtual table] interface to 6066** pass information into and receive the reply from the [xBestIndex] 6067** method of a [virtual table module]. The fields under **Inputs** are the 6068** inputs to xBestIndex and are read-only. xBestIndex inserts its 6069** results into the **Outputs** fields. 6070** 6071** ^(The aConstraint[] array records WHERE clause constraints of the form: 6072** 6073** <blockquote>column OP expr</blockquote> 6074** 6075** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6076** stored in aConstraint[].op using one of the 6077** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6078** ^(The index of the column is stored in 6079** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6080** expr on the right-hand side can be evaluated (and thus the constraint 6081** is usable) and false if it cannot.)^ 6082** 6083** ^The optimizer automatically inverts terms of the form "expr OP column" 6084** and makes other simplifications to the WHERE clause in an attempt to 6085** get as many WHERE clause terms into the form shown above as possible. 6086** ^The aConstraint[] array only reports WHERE clause terms that are 6087** relevant to the particular virtual table being queried. 6088** 6089** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6090** ^Each term of aOrderBy records a column of the ORDER BY clause. 6091** 6092** The colUsed field indicates which columns of the virtual table may be 6093** required by the current scan. Virtual table columns are numbered from 6094** zero in the order in which they appear within the CREATE TABLE statement 6095** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6096** the corresponding bit is set within the colUsed mask if the column may be 6097** required by SQLite. If the table has at least 64 columns and any column 6098** to the right of the first 63 is required, then bit 63 of colUsed is also 6099** set. In other words, column iCol may be required if the expression 6100** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6101** non-zero. 6102** 6103** The [xBestIndex] method must fill aConstraintUsage[] with information 6104** about what parameters to pass to xFilter. ^If argvIndex>0 then 6105** the right-hand side of the corresponding aConstraint[] is evaluated 6106** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6107** is true, then the constraint is assumed to be fully handled by the 6108** virtual table and is not checked again by SQLite.)^ 6109** 6110** ^The idxNum and idxPtr values are recorded and passed into the 6111** [xFilter] method. 6112** ^[sqlite3_free()] is used to free idxPtr if and only if 6113** needToFreeIdxPtr is true. 6114** 6115** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6116** the correct order to satisfy the ORDER BY clause so that no separate 6117** sorting step is required. 6118** 6119** ^The estimatedCost value is an estimate of the cost of a particular 6120** strategy. A cost of N indicates that the cost of the strategy is similar 6121** to a linear scan of an SQLite table with N rows. A cost of log(N) 6122** indicates that the expense of the operation is similar to that of a 6123** binary search on a unique indexed field of an SQLite table with N rows. 6124** 6125** ^The estimatedRows value is an estimate of the number of rows that 6126** will be returned by the strategy. 6127** 6128** The xBestIndex method may optionally populate the idxFlags field with a 6129** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6130** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6131** assumes that the strategy may visit at most one row. 6132** 6133** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6134** SQLite also assumes that if a call to the xUpdate() method is made as 6135** part of the same statement to delete or update a virtual table row and the 6136** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6137** any database changes. In other words, if the xUpdate() returns 6138** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6139** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6140** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6141** the xUpdate method are automatically rolled back by SQLite. 6142** 6143** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6144** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6145** If a virtual table extension is 6146** used with an SQLite version earlier than 3.8.2, the results of attempting 6147** to read or write the estimatedRows field are undefined (but are likely 6148** to included crashing the application). The estimatedRows field should 6149** therefore only be used if [sqlite3_libversion_number()] returns a 6150** value greater than or equal to 3008002. Similarly, the idxFlags field 6151** was added for [version 3.9.0] ([dateof:3.9.0]). 6152** It may therefore only be used if 6153** sqlite3_libversion_number() returns a value greater than or equal to 6154** 3009000. 6155*/ 6156struct sqlite3_index_info { 6157 /* Inputs */ 6158 int nConstraint; /* Number of entries in aConstraint */ 6159 struct sqlite3_index_constraint { 6160 int iColumn; /* Column constrained. -1 for ROWID */ 6161 unsigned char op; /* Constraint operator */ 6162 unsigned char usable; /* True if this constraint is usable */ 6163 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6164 } *aConstraint; /* Table of WHERE clause constraints */ 6165 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6166 struct sqlite3_index_orderby { 6167 int iColumn; /* Column number */ 6168 unsigned char desc; /* True for DESC. False for ASC. */ 6169 } *aOrderBy; /* The ORDER BY clause */ 6170 /* Outputs */ 6171 struct sqlite3_index_constraint_usage { 6172 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6173 unsigned char omit; /* Do not code a test for this constraint */ 6174 } *aConstraintUsage; 6175 int idxNum; /* Number used to identify the index */ 6176 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6177 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6178 int orderByConsumed; /* True if output is already ordered */ 6179 double estimatedCost; /* Estimated cost of using this index */ 6180 /* Fields below are only available in SQLite 3.8.2 and later */ 6181 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6182 /* Fields below are only available in SQLite 3.9.0 and later */ 6183 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6184 /* Fields below are only available in SQLite 3.10.0 and later */ 6185 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6186}; 6187 6188/* 6189** CAPI3REF: Virtual Table Scan Flags 6190*/ 6191#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6192 6193/* 6194** CAPI3REF: Virtual Table Constraint Operator Codes 6195** 6196** These macros defined the allowed values for the 6197** [sqlite3_index_info].aConstraint[].op field. Each value represents 6198** an operator that is part of a constraint term in the wHERE clause of 6199** a query that uses a [virtual table]. 6200*/ 6201#define SQLITE_INDEX_CONSTRAINT_EQ 2 6202#define SQLITE_INDEX_CONSTRAINT_GT 4 6203#define SQLITE_INDEX_CONSTRAINT_LE 8 6204#define SQLITE_INDEX_CONSTRAINT_LT 16 6205#define SQLITE_INDEX_CONSTRAINT_GE 32 6206#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6207#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6208#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6209#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6210 6211/* 6212** CAPI3REF: Register A Virtual Table Implementation 6213** METHOD: sqlite3 6214** 6215** ^These routines are used to register a new [virtual table module] name. 6216** ^Module names must be registered before 6217** creating a new [virtual table] using the module and before using a 6218** preexisting [virtual table] for the module. 6219** 6220** ^The module name is registered on the [database connection] specified 6221** by the first parameter. ^The name of the module is given by the 6222** second parameter. ^The third parameter is a pointer to 6223** the implementation of the [virtual table module]. ^The fourth 6224** parameter is an arbitrary client data pointer that is passed through 6225** into the [xCreate] and [xConnect] methods of the virtual table module 6226** when a new virtual table is be being created or reinitialized. 6227** 6228** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6229** is a pointer to a destructor for the pClientData. ^SQLite will 6230** invoke the destructor function (if it is not NULL) when SQLite 6231** no longer needs the pClientData pointer. ^The destructor will also 6232** be invoked if the call to sqlite3_create_module_v2() fails. 6233** ^The sqlite3_create_module() 6234** interface is equivalent to sqlite3_create_module_v2() with a NULL 6235** destructor. 6236*/ 6237int sqlite3_create_module( 6238 sqlite3 *db, /* SQLite connection to register module with */ 6239 const char *zName, /* Name of the module */ 6240 const sqlite3_module *p, /* Methods for the module */ 6241 void *pClientData /* Client data for xCreate/xConnect */ 6242); 6243int sqlite3_create_module_v2( 6244 sqlite3 *db, /* SQLite connection to register module with */ 6245 const char *zName, /* Name of the module */ 6246 const sqlite3_module *p, /* Methods for the module */ 6247 void *pClientData, /* Client data for xCreate/xConnect */ 6248 void(*xDestroy)(void*) /* Module destructor function */ 6249); 6250 6251/* 6252** CAPI3REF: Virtual Table Instance Object 6253** KEYWORDS: sqlite3_vtab 6254** 6255** Every [virtual table module] implementation uses a subclass 6256** of this object to describe a particular instance 6257** of the [virtual table]. Each subclass will 6258** be tailored to the specific needs of the module implementation. 6259** The purpose of this superclass is to define certain fields that are 6260** common to all module implementations. 6261** 6262** ^Virtual tables methods can set an error message by assigning a 6263** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 6264** take care that any prior string is freed by a call to [sqlite3_free()] 6265** prior to assigning a new string to zErrMsg. ^After the error message 6266** is delivered up to the client application, the string will be automatically 6267** freed by sqlite3_free() and the zErrMsg field will be zeroed. 6268*/ 6269struct sqlite3_vtab { 6270 const sqlite3_module *pModule; /* The module for this virtual table */ 6271 int nRef; /* Number of open cursors */ 6272 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 6273 /* Virtual table implementations will typically add additional fields */ 6274}; 6275 6276/* 6277** CAPI3REF: Virtual Table Cursor Object 6278** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 6279** 6280** Every [virtual table module] implementation uses a subclass of the 6281** following structure to describe cursors that point into the 6282** [virtual table] and are used 6283** to loop through the virtual table. Cursors are created using the 6284** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 6285** by the [sqlite3_module.xClose | xClose] method. Cursors are used 6286** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 6287** of the module. Each module implementation will define 6288** the content of a cursor structure to suit its own needs. 6289** 6290** This superclass exists in order to define fields of the cursor that 6291** are common to all implementations. 6292*/ 6293struct sqlite3_vtab_cursor { 6294 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 6295 /* Virtual table implementations will typically add additional fields */ 6296}; 6297 6298/* 6299** CAPI3REF: Declare The Schema Of A Virtual Table 6300** 6301** ^The [xCreate] and [xConnect] methods of a 6302** [virtual table module] call this interface 6303** to declare the format (the names and datatypes of the columns) of 6304** the virtual tables they implement. 6305*/ 6306int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 6307 6308/* 6309** CAPI3REF: Overload A Function For A Virtual Table 6310** METHOD: sqlite3 6311** 6312** ^(Virtual tables can provide alternative implementations of functions 6313** using the [xFindFunction] method of the [virtual table module]. 6314** But global versions of those functions 6315** must exist in order to be overloaded.)^ 6316** 6317** ^(This API makes sure a global version of a function with a particular 6318** name and number of parameters exists. If no such function exists 6319** before this API is called, a new function is created.)^ ^The implementation 6320** of the new function always causes an exception to be thrown. So 6321** the new function is not good for anything by itself. Its only 6322** purpose is to be a placeholder function that can be overloaded 6323** by a [virtual table]. 6324*/ 6325int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 6326 6327/* 6328** The interface to the virtual-table mechanism defined above (back up 6329** to a comment remarkably similar to this one) is currently considered 6330** to be experimental. The interface might change in incompatible ways. 6331** If this is a problem for you, do not use the interface at this time. 6332** 6333** When the virtual-table mechanism stabilizes, we will declare the 6334** interface fixed, support it indefinitely, and remove this comment. 6335*/ 6336 6337/* 6338** CAPI3REF: A Handle To An Open BLOB 6339** KEYWORDS: {BLOB handle} {BLOB handles} 6340** 6341** An instance of this object represents an open BLOB on which 6342** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 6343** ^Objects of this type are created by [sqlite3_blob_open()] 6344** and destroyed by [sqlite3_blob_close()]. 6345** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 6346** can be used to read or write small subsections of the BLOB. 6347** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 6348*/ 6349typedef struct sqlite3_blob sqlite3_blob; 6350 6351/* 6352** CAPI3REF: Open A BLOB For Incremental I/O 6353** METHOD: sqlite3 6354** CONSTRUCTOR: sqlite3_blob 6355** 6356** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 6357** in row iRow, column zColumn, table zTable in database zDb; 6358** in other words, the same BLOB that would be selected by: 6359** 6360** <pre> 6361** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 6362** </pre>)^ 6363** 6364** ^(Parameter zDb is not the filename that contains the database, but 6365** rather the symbolic name of the database. For attached databases, this is 6366** the name that appears after the AS keyword in the [ATTACH] statement. 6367** For the main database file, the database name is "main". For TEMP 6368** tables, the database name is "temp".)^ 6369** 6370** ^If the flags parameter is non-zero, then the BLOB is opened for read 6371** and write access. ^If the flags parameter is zero, the BLOB is opened for 6372** read-only access. 6373** 6374** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 6375** in *ppBlob. Otherwise an [error code] is returned and, unless the error 6376** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 6377** the API is not misused, it is always safe to call [sqlite3_blob_close()] 6378** on *ppBlob after this function it returns. 6379** 6380** This function fails with SQLITE_ERROR if any of the following are true: 6381** <ul> 6382** <li> ^(Database zDb does not exist)^, 6383** <li> ^(Table zTable does not exist within database zDb)^, 6384** <li> ^(Table zTable is a WITHOUT ROWID table)^, 6385** <li> ^(Column zColumn does not exist)^, 6386** <li> ^(Row iRow is not present in the table)^, 6387** <li> ^(The specified column of row iRow contains a value that is not 6388** a TEXT or BLOB value)^, 6389** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 6390** constraint and the blob is being opened for read/write access)^, 6391** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 6392** column zColumn is part of a [child key] definition and the blob is 6393** being opened for read/write access)^. 6394** </ul> 6395** 6396** ^Unless it returns SQLITE_MISUSE, this function sets the 6397** [database connection] error code and message accessible via 6398** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6399** 6400** A BLOB referenced by sqlite3_blob_open() may be read using the 6401** [sqlite3_blob_read()] interface and modified by using 6402** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 6403** different row of the same table using the [sqlite3_blob_reopen()] 6404** interface. However, the column, table, or database of a [BLOB handle] 6405** cannot be changed after the [BLOB handle] is opened. 6406** 6407** ^(If the row that a BLOB handle points to is modified by an 6408** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 6409** then the BLOB handle is marked as "expired". 6410** This is true if any column of the row is changed, even a column 6411** other than the one the BLOB handle is open on.)^ 6412** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 6413** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 6414** ^(Changes written into a BLOB prior to the BLOB expiring are not 6415** rolled back by the expiration of the BLOB. Such changes will eventually 6416** commit if the transaction continues to completion.)^ 6417** 6418** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 6419** the opened blob. ^The size of a blob may not be changed by this 6420** interface. Use the [UPDATE] SQL command to change the size of a 6421** blob. 6422** 6423** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 6424** and the built-in [zeroblob] SQL function may be used to create a 6425** zero-filled blob to read or write using the incremental-blob interface. 6426** 6427** To avoid a resource leak, every open [BLOB handle] should eventually 6428** be released by a call to [sqlite3_blob_close()]. 6429** 6430** See also: [sqlite3_blob_close()], 6431** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 6432** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 6433*/ 6434int sqlite3_blob_open( 6435 sqlite3*, 6436 const char *zDb, 6437 const char *zTable, 6438 const char *zColumn, 6439 sqlite3_int64 iRow, 6440 int flags, 6441 sqlite3_blob **ppBlob 6442); 6443 6444/* 6445** CAPI3REF: Move a BLOB Handle to a New Row 6446** METHOD: sqlite3_blob 6447** 6448** ^This function is used to move an existing [BLOB handle] so that it points 6449** to a different row of the same database table. ^The new row is identified 6450** by the rowid value passed as the second argument. Only the row can be 6451** changed. ^The database, table and column on which the blob handle is open 6452** remain the same. Moving an existing [BLOB handle] to a new row is 6453** faster than closing the existing handle and opening a new one. 6454** 6455** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 6456** it must exist and there must be either a blob or text value stored in 6457** the nominated column.)^ ^If the new row is not present in the table, or if 6458** it does not contain a blob or text value, or if another error occurs, an 6459** SQLite error code is returned and the blob handle is considered aborted. 6460** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 6461** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 6462** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 6463** always returns zero. 6464** 6465** ^This function sets the database handle error code and message. 6466*/ 6467int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 6468 6469/* 6470** CAPI3REF: Close A BLOB Handle 6471** DESTRUCTOR: sqlite3_blob 6472** 6473** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 6474** unconditionally. Even if this routine returns an error code, the 6475** handle is still closed.)^ 6476** 6477** ^If the blob handle being closed was opened for read-write access, and if 6478** the database is in auto-commit mode and there are no other open read-write 6479** blob handles or active write statements, the current transaction is 6480** committed. ^If an error occurs while committing the transaction, an error 6481** code is returned and the transaction rolled back. 6482** 6483** Calling this function with an argument that is not a NULL pointer or an 6484** open blob handle results in undefined behaviour. ^Calling this routine 6485** with a null pointer (such as would be returned by a failed call to 6486** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 6487** is passed a valid open blob handle, the values returned by the 6488** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 6489*/ 6490int sqlite3_blob_close(sqlite3_blob *); 6491 6492/* 6493** CAPI3REF: Return The Size Of An Open BLOB 6494** METHOD: sqlite3_blob 6495** 6496** ^Returns the size in bytes of the BLOB accessible via the 6497** successfully opened [BLOB handle] in its only argument. ^The 6498** incremental blob I/O routines can only read or overwriting existing 6499** blob content; they cannot change the size of a blob. 6500** 6501** This routine only works on a [BLOB handle] which has been created 6502** by a prior successful call to [sqlite3_blob_open()] and which has not 6503** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6504** to this routine results in undefined and probably undesirable behavior. 6505*/ 6506int sqlite3_blob_bytes(sqlite3_blob *); 6507 6508/* 6509** CAPI3REF: Read Data From A BLOB Incrementally 6510** METHOD: sqlite3_blob 6511** 6512** ^(This function is used to read data from an open [BLOB handle] into a 6513** caller-supplied buffer. N bytes of data are copied into buffer Z 6514** from the open BLOB, starting at offset iOffset.)^ 6515** 6516** ^If offset iOffset is less than N bytes from the end of the BLOB, 6517** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6518** less than zero, [SQLITE_ERROR] is returned and no data is read. 6519** ^The size of the blob (and hence the maximum value of N+iOffset) 6520** can be determined using the [sqlite3_blob_bytes()] interface. 6521** 6522** ^An attempt to read from an expired [BLOB handle] fails with an 6523** error code of [SQLITE_ABORT]. 6524** 6525** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6526** Otherwise, an [error code] or an [extended error code] is returned.)^ 6527** 6528** This routine only works on a [BLOB handle] which has been created 6529** by a prior successful call to [sqlite3_blob_open()] and which has not 6530** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6531** to this routine results in undefined and probably undesirable behavior. 6532** 6533** See also: [sqlite3_blob_write()]. 6534*/ 6535int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6536 6537/* 6538** CAPI3REF: Write Data Into A BLOB Incrementally 6539** METHOD: sqlite3_blob 6540** 6541** ^(This function is used to write data into an open [BLOB handle] from a 6542** caller-supplied buffer. N bytes of data are copied from the buffer Z 6543** into the open BLOB, starting at offset iOffset.)^ 6544** 6545** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6546** Otherwise, an [error code] or an [extended error code] is returned.)^ 6547** ^Unless SQLITE_MISUSE is returned, this function sets the 6548** [database connection] error code and message accessible via 6549** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6550** 6551** ^If the [BLOB handle] passed as the first argument was not opened for 6552** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6553** this function returns [SQLITE_READONLY]. 6554** 6555** This function may only modify the contents of the BLOB; it is 6556** not possible to increase the size of a BLOB using this API. 6557** ^If offset iOffset is less than N bytes from the end of the BLOB, 6558** [SQLITE_ERROR] is returned and no data is written. The size of the 6559** BLOB (and hence the maximum value of N+iOffset) can be determined 6560** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6561** than zero [SQLITE_ERROR] is returned and no data is written. 6562** 6563** ^An attempt to write to an expired [BLOB handle] fails with an 6564** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6565** before the [BLOB handle] expired are not rolled back by the 6566** expiration of the handle, though of course those changes might 6567** have been overwritten by the statement that expired the BLOB handle 6568** or by other independent statements. 6569** 6570** This routine only works on a [BLOB handle] which has been created 6571** by a prior successful call to [sqlite3_blob_open()] and which has not 6572** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6573** to this routine results in undefined and probably undesirable behavior. 6574** 6575** See also: [sqlite3_blob_read()]. 6576*/ 6577int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6578 6579/* 6580** CAPI3REF: Virtual File System Objects 6581** 6582** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6583** that SQLite uses to interact 6584** with the underlying operating system. Most SQLite builds come with a 6585** single default VFS that is appropriate for the host computer. 6586** New VFSes can be registered and existing VFSes can be unregistered. 6587** The following interfaces are provided. 6588** 6589** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6590** ^Names are case sensitive. 6591** ^Names are zero-terminated UTF-8 strings. 6592** ^If there is no match, a NULL pointer is returned. 6593** ^If zVfsName is NULL then the default VFS is returned. 6594** 6595** ^New VFSes are registered with sqlite3_vfs_register(). 6596** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6597** ^The same VFS can be registered multiple times without injury. 6598** ^To make an existing VFS into the default VFS, register it again 6599** with the makeDflt flag set. If two different VFSes with the 6600** same name are registered, the behavior is undefined. If a 6601** VFS is registered with a name that is NULL or an empty string, 6602** then the behavior is undefined. 6603** 6604** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6605** ^(If the default VFS is unregistered, another VFS is chosen as 6606** the default. The choice for the new VFS is arbitrary.)^ 6607*/ 6608sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6609int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6610int sqlite3_vfs_unregister(sqlite3_vfs*); 6611 6612/* 6613** CAPI3REF: Mutexes 6614** 6615** The SQLite core uses these routines for thread 6616** synchronization. Though they are intended for internal 6617** use by SQLite, code that links against SQLite is 6618** permitted to use any of these routines. 6619** 6620** The SQLite source code contains multiple implementations 6621** of these mutex routines. An appropriate implementation 6622** is selected automatically at compile-time. The following 6623** implementations are available in the SQLite core: 6624** 6625** <ul> 6626** <li> SQLITE_MUTEX_PTHREADS 6627** <li> SQLITE_MUTEX_W32 6628** <li> SQLITE_MUTEX_NOOP 6629** </ul> 6630** 6631** The SQLITE_MUTEX_NOOP implementation is a set of routines 6632** that does no real locking and is appropriate for use in 6633** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6634** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6635** and Windows. 6636** 6637** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6638** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6639** implementation is included with the library. In this case the 6640** application must supply a custom mutex implementation using the 6641** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6642** before calling sqlite3_initialize() or any other public sqlite3_ 6643** function that calls sqlite3_initialize(). 6644** 6645** ^The sqlite3_mutex_alloc() routine allocates a new 6646** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6647** routine returns NULL if it is unable to allocate the requested 6648** mutex. The argument to sqlite3_mutex_alloc() must one of these 6649** integer constants: 6650** 6651** <ul> 6652** <li> SQLITE_MUTEX_FAST 6653** <li> SQLITE_MUTEX_RECURSIVE 6654** <li> SQLITE_MUTEX_STATIC_MASTER 6655** <li> SQLITE_MUTEX_STATIC_MEM 6656** <li> SQLITE_MUTEX_STATIC_OPEN 6657** <li> SQLITE_MUTEX_STATIC_PRNG 6658** <li> SQLITE_MUTEX_STATIC_LRU 6659** <li> SQLITE_MUTEX_STATIC_PMEM 6660** <li> SQLITE_MUTEX_STATIC_APP1 6661** <li> SQLITE_MUTEX_STATIC_APP2 6662** <li> SQLITE_MUTEX_STATIC_APP3 6663** <li> SQLITE_MUTEX_STATIC_VFS1 6664** <li> SQLITE_MUTEX_STATIC_VFS2 6665** <li> SQLITE_MUTEX_STATIC_VFS3 6666** </ul> 6667** 6668** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6669** cause sqlite3_mutex_alloc() to create 6670** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6671** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6672** The mutex implementation does not need to make a distinction 6673** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6674** not want to. SQLite will only request a recursive mutex in 6675** cases where it really needs one. If a faster non-recursive mutex 6676** implementation is available on the host platform, the mutex subsystem 6677** might return such a mutex in response to SQLITE_MUTEX_FAST. 6678** 6679** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6680** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6681** a pointer to a static preexisting mutex. ^Nine static mutexes are 6682** used by the current version of SQLite. Future versions of SQLite 6683** may add additional static mutexes. Static mutexes are for internal 6684** use by SQLite only. Applications that use SQLite mutexes should 6685** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6686** SQLITE_MUTEX_RECURSIVE. 6687** 6688** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6689** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6690** returns a different mutex on every call. ^For the static 6691** mutex types, the same mutex is returned on every call that has 6692** the same type number. 6693** 6694** ^The sqlite3_mutex_free() routine deallocates a previously 6695** allocated dynamic mutex. Attempting to deallocate a static 6696** mutex results in undefined behavior. 6697** 6698** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6699** to enter a mutex. ^If another thread is already within the mutex, 6700** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6701** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6702** upon successful entry. ^(Mutexes created using 6703** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6704** In such cases, the 6705** mutex must be exited an equal number of times before another thread 6706** can enter.)^ If the same thread tries to enter any mutex other 6707** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6708** 6709** ^(Some systems (for example, Windows 95) do not support the operation 6710** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6711** will always return SQLITE_BUSY. The SQLite core only ever uses 6712** sqlite3_mutex_try() as an optimization so this is acceptable 6713** behavior.)^ 6714** 6715** ^The sqlite3_mutex_leave() routine exits a mutex that was 6716** previously entered by the same thread. The behavior 6717** is undefined if the mutex is not currently entered by the 6718** calling thread or is not currently allocated. 6719** 6720** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6721** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6722** behave as no-ops. 6723** 6724** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6725*/ 6726sqlite3_mutex *sqlite3_mutex_alloc(int); 6727void sqlite3_mutex_free(sqlite3_mutex*); 6728void sqlite3_mutex_enter(sqlite3_mutex*); 6729int sqlite3_mutex_try(sqlite3_mutex*); 6730void sqlite3_mutex_leave(sqlite3_mutex*); 6731 6732/* 6733** CAPI3REF: Mutex Methods Object 6734** 6735** An instance of this structure defines the low-level routines 6736** used to allocate and use mutexes. 6737** 6738** Usually, the default mutex implementations provided by SQLite are 6739** sufficient, however the application has the option of substituting a custom 6740** implementation for specialized deployments or systems for which SQLite 6741** does not provide a suitable implementation. In this case, the application 6742** creates and populates an instance of this structure to pass 6743** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6744** Additionally, an instance of this structure can be used as an 6745** output variable when querying the system for the current mutex 6746** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6747** 6748** ^The xMutexInit method defined by this structure is invoked as 6749** part of system initialization by the sqlite3_initialize() function. 6750** ^The xMutexInit routine is called by SQLite exactly once for each 6751** effective call to [sqlite3_initialize()]. 6752** 6753** ^The xMutexEnd method defined by this structure is invoked as 6754** part of system shutdown by the sqlite3_shutdown() function. The 6755** implementation of this method is expected to release all outstanding 6756** resources obtained by the mutex methods implementation, especially 6757** those obtained by the xMutexInit method. ^The xMutexEnd() 6758** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6759** 6760** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6761** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6762** xMutexNotheld) implement the following interfaces (respectively): 6763** 6764** <ul> 6765** <li> [sqlite3_mutex_alloc()] </li> 6766** <li> [sqlite3_mutex_free()] </li> 6767** <li> [sqlite3_mutex_enter()] </li> 6768** <li> [sqlite3_mutex_try()] </li> 6769** <li> [sqlite3_mutex_leave()] </li> 6770** <li> [sqlite3_mutex_held()] </li> 6771** <li> [sqlite3_mutex_notheld()] </li> 6772** </ul>)^ 6773** 6774** The only difference is that the public sqlite3_XXX functions enumerated 6775** above silently ignore any invocations that pass a NULL pointer instead 6776** of a valid mutex handle. The implementations of the methods defined 6777** by this structure are not required to handle this case, the results 6778** of passing a NULL pointer instead of a valid mutex handle are undefined 6779** (i.e. it is acceptable to provide an implementation that segfaults if 6780** it is passed a NULL pointer). 6781** 6782** The xMutexInit() method must be threadsafe. It must be harmless to 6783** invoke xMutexInit() multiple times within the same process and without 6784** intervening calls to xMutexEnd(). Second and subsequent calls to 6785** xMutexInit() must be no-ops. 6786** 6787** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6788** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6789** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6790** memory allocation for a fast or recursive mutex. 6791** 6792** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6793** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6794** If xMutexInit fails in any way, it is expected to clean up after itself 6795** prior to returning. 6796*/ 6797typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6798struct sqlite3_mutex_methods { 6799 int (*xMutexInit)(void); 6800 int (*xMutexEnd)(void); 6801 sqlite3_mutex *(*xMutexAlloc)(int); 6802 void (*xMutexFree)(sqlite3_mutex *); 6803 void (*xMutexEnter)(sqlite3_mutex *); 6804 int (*xMutexTry)(sqlite3_mutex *); 6805 void (*xMutexLeave)(sqlite3_mutex *); 6806 int (*xMutexHeld)(sqlite3_mutex *); 6807 int (*xMutexNotheld)(sqlite3_mutex *); 6808}; 6809 6810/* 6811** CAPI3REF: Mutex Verification Routines 6812** 6813** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6814** are intended for use inside assert() statements. The SQLite core 6815** never uses these routines except inside an assert() and applications 6816** are advised to follow the lead of the core. The SQLite core only 6817** provides implementations for these routines when it is compiled 6818** with the SQLITE_DEBUG flag. External mutex implementations 6819** are only required to provide these routines if SQLITE_DEBUG is 6820** defined and if NDEBUG is not defined. 6821** 6822** These routines should return true if the mutex in their argument 6823** is held or not held, respectively, by the calling thread. 6824** 6825** The implementation is not required to provide versions of these 6826** routines that actually work. If the implementation does not provide working 6827** versions of these routines, it should at least provide stubs that always 6828** return true so that one does not get spurious assertion failures. 6829** 6830** If the argument to sqlite3_mutex_held() is a NULL pointer then 6831** the routine should return 1. This seems counter-intuitive since 6832** clearly the mutex cannot be held if it does not exist. But 6833** the reason the mutex does not exist is because the build is not 6834** using mutexes. And we do not want the assert() containing the 6835** call to sqlite3_mutex_held() to fail, so a non-zero return is 6836** the appropriate thing to do. The sqlite3_mutex_notheld() 6837** interface should also return 1 when given a NULL pointer. 6838*/ 6839#ifndef NDEBUG 6840int sqlite3_mutex_held(sqlite3_mutex*); 6841int sqlite3_mutex_notheld(sqlite3_mutex*); 6842#endif 6843 6844/* 6845** CAPI3REF: Mutex Types 6846** 6847** The [sqlite3_mutex_alloc()] interface takes a single argument 6848** which is one of these integer constants. 6849** 6850** The set of static mutexes may change from one SQLite release to the 6851** next. Applications that override the built-in mutex logic must be 6852** prepared to accommodate additional static mutexes. 6853*/ 6854#define SQLITE_MUTEX_FAST 0 6855#define SQLITE_MUTEX_RECURSIVE 1 6856#define SQLITE_MUTEX_STATIC_MASTER 2 6857#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6858#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6859#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6860#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 6861#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6862#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6863#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6864#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6865#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6866#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6867#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 6868#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 6869#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 6870 6871/* 6872** CAPI3REF: Retrieve the mutex for a database connection 6873** METHOD: sqlite3 6874** 6875** ^This interface returns a pointer the [sqlite3_mutex] object that 6876** serializes access to the [database connection] given in the argument 6877** when the [threading mode] is Serialized. 6878** ^If the [threading mode] is Single-thread or Multi-thread then this 6879** routine returns a NULL pointer. 6880*/ 6881sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 6882 6883/* 6884** CAPI3REF: Low-Level Control Of Database Files 6885** METHOD: sqlite3 6886** 6887** ^The [sqlite3_file_control()] interface makes a direct call to the 6888** xFileControl method for the [sqlite3_io_methods] object associated 6889** with a particular database identified by the second argument. ^The 6890** name of the database is "main" for the main database or "temp" for the 6891** TEMP database, or the name that appears after the AS keyword for 6892** databases that are added using the [ATTACH] SQL command. 6893** ^A NULL pointer can be used in place of "main" to refer to the 6894** main database file. 6895** ^The third and fourth parameters to this routine 6896** are passed directly through to the second and third parameters of 6897** the xFileControl method. ^The return value of the xFileControl 6898** method becomes the return value of this routine. 6899** 6900** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 6901** a pointer to the underlying [sqlite3_file] object to be written into 6902** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 6903** case is a short-circuit path which does not actually invoke the 6904** underlying sqlite3_io_methods.xFileControl method. 6905** 6906** ^If the second parameter (zDbName) does not match the name of any 6907** open database file, then SQLITE_ERROR is returned. ^This error 6908** code is not remembered and will not be recalled by [sqlite3_errcode()] 6909** or [sqlite3_errmsg()]. The underlying xFileControl method might 6910** also return SQLITE_ERROR. There is no way to distinguish between 6911** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6912** xFileControl method. 6913** 6914** See also: [SQLITE_FCNTL_LOCKSTATE] 6915*/ 6916int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6917 6918/* 6919** CAPI3REF: Testing Interface 6920** 6921** ^The sqlite3_test_control() interface is used to read out internal 6922** state of SQLite and to inject faults into SQLite for testing 6923** purposes. ^The first parameter is an operation code that determines 6924** the number, meaning, and operation of all subsequent parameters. 6925** 6926** This interface is not for use by applications. It exists solely 6927** for verifying the correct operation of the SQLite library. Depending 6928** on how the SQLite library is compiled, this interface might not exist. 6929** 6930** The details of the operation codes, their meanings, the parameters 6931** they take, and what they do are all subject to change without notice. 6932** Unlike most of the SQLite API, this function is not guaranteed to 6933** operate consistently from one release to the next. 6934*/ 6935int sqlite3_test_control(int op, ...); 6936 6937/* 6938** CAPI3REF: Testing Interface Operation Codes 6939** 6940** These constants are the valid operation code parameters used 6941** as the first argument to [sqlite3_test_control()]. 6942** 6943** These parameters and their meanings are subject to change 6944** without notice. These values are for testing purposes only. 6945** Applications should not use any of these parameters or the 6946** [sqlite3_test_control()] interface. 6947*/ 6948#define SQLITE_TESTCTRL_FIRST 5 6949#define SQLITE_TESTCTRL_PRNG_SAVE 5 6950#define SQLITE_TESTCTRL_PRNG_RESTORE 6 6951#define SQLITE_TESTCTRL_PRNG_RESET 7 6952#define SQLITE_TESTCTRL_BITVEC_TEST 8 6953#define SQLITE_TESTCTRL_FAULT_INSTALL 9 6954#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 6955#define SQLITE_TESTCTRL_PENDING_BYTE 11 6956#define SQLITE_TESTCTRL_ASSERT 12 6957#define SQLITE_TESTCTRL_ALWAYS 13 6958#define SQLITE_TESTCTRL_RESERVE 14 6959#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 6960#define SQLITE_TESTCTRL_ISKEYWORD 16 6961#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 6962#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 6963#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 6964#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 6965#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 6966#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 6967#define SQLITE_TESTCTRL_BYTEORDER 22 6968#define SQLITE_TESTCTRL_ISINIT 23 6969#define SQLITE_TESTCTRL_SORTER_MMAP 24 6970#define SQLITE_TESTCTRL_IMPOSTER 25 6971#define SQLITE_TESTCTRL_LAST 25 6972 6973/* 6974** CAPI3REF: SQLite Runtime Status 6975** 6976** ^These interfaces are used to retrieve runtime status information 6977** about the performance of SQLite, and optionally to reset various 6978** highwater marks. ^The first argument is an integer code for 6979** the specific parameter to measure. ^(Recognized integer codes 6980** are of the form [status parameters | SQLITE_STATUS_...].)^ 6981** ^The current value of the parameter is returned into *pCurrent. 6982** ^The highest recorded value is returned in *pHighwater. ^If the 6983** resetFlag is true, then the highest record value is reset after 6984** *pHighwater is written. ^(Some parameters do not record the highest 6985** value. For those parameters 6986** nothing is written into *pHighwater and the resetFlag is ignored.)^ 6987** ^(Other parameters record only the highwater mark and not the current 6988** value. For these latter parameters nothing is written into *pCurrent.)^ 6989** 6990** ^The sqlite3_status() and sqlite3_status64() routines return 6991** SQLITE_OK on success and a non-zero [error code] on failure. 6992** 6993** If either the current value or the highwater mark is too large to 6994** be represented by a 32-bit integer, then the values returned by 6995** sqlite3_status() are undefined. 6996** 6997** See also: [sqlite3_db_status()] 6998*/ 6999int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 7000int sqlite3_status64( 7001 int op, 7002 sqlite3_int64 *pCurrent, 7003 sqlite3_int64 *pHighwater, 7004 int resetFlag 7005); 7006 7007 7008/* 7009** CAPI3REF: Status Parameters 7010** KEYWORDS: {status parameters} 7011** 7012** These integer constants designate various run-time status parameters 7013** that can be returned by [sqlite3_status()]. 7014** 7015** <dl> 7016** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 7017** <dd>This parameter is the current amount of memory checked out 7018** using [sqlite3_malloc()], either directly or indirectly. The 7019** figure includes calls made to [sqlite3_malloc()] by the application 7020** and internal memory usage by the SQLite library. Scratch memory 7021** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 7022** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 7023** this parameter. The amount returned is the sum of the allocation 7024** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 7025** 7026** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 7027** <dd>This parameter records the largest memory allocation request 7028** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 7029** internal equivalents). Only the value returned in the 7030** *pHighwater parameter to [sqlite3_status()] is of interest. 7031** The value written into the *pCurrent parameter is undefined.</dd>)^ 7032** 7033** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 7034** <dd>This parameter records the number of separate memory allocations 7035** currently checked out.</dd>)^ 7036** 7037** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 7038** <dd>This parameter returns the number of pages used out of the 7039** [pagecache memory allocator] that was configured using 7040** [SQLITE_CONFIG_PAGECACHE]. The 7041** value returned is in pages, not in bytes.</dd>)^ 7042** 7043** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 7044** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 7045** <dd>This parameter returns the number of bytes of page cache 7046** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 7047** buffer and where forced to overflow to [sqlite3_malloc()]. The 7048** returned value includes allocations that overflowed because they 7049** where too large (they were larger than the "sz" parameter to 7050** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 7051** no space was left in the page cache.</dd>)^ 7052** 7053** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 7054** <dd>This parameter records the largest memory allocation request 7055** handed to [pagecache memory allocator]. Only the value returned in the 7056** *pHighwater parameter to [sqlite3_status()] is of interest. 7057** The value written into the *pCurrent parameter is undefined.</dd>)^ 7058** 7059** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 7060** <dd>This parameter returns the number of allocations used out of the 7061** [scratch memory allocator] configured using 7062** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 7063** in bytes. Since a single thread may only have one scratch allocation 7064** outstanding at time, this parameter also reports the number of threads 7065** using scratch memory at the same time.</dd>)^ 7066** 7067** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 7068** <dd>This parameter returns the number of bytes of scratch memory 7069** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 7070** buffer and where forced to overflow to [sqlite3_malloc()]. The values 7071** returned include overflows because the requested allocation was too 7072** larger (that is, because the requested allocation was larger than the 7073** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 7074** slots were available. 7075** </dd>)^ 7076** 7077** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 7078** <dd>This parameter records the largest memory allocation request 7079** handed to [scratch memory allocator]. Only the value returned in the 7080** *pHighwater parameter to [sqlite3_status()] is of interest. 7081** The value written into the *pCurrent parameter is undefined.</dd>)^ 7082** 7083** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 7084** <dd>The *pHighwater parameter records the deepest parser stack. 7085** The *pCurrent value is undefined. The *pHighwater value is only 7086** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 7087** </dl> 7088** 7089** New status parameters may be added from time to time. 7090*/ 7091#define SQLITE_STATUS_MEMORY_USED 0 7092#define SQLITE_STATUS_PAGECACHE_USED 1 7093#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 7094#define SQLITE_STATUS_SCRATCH_USED 3 7095#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 7096#define SQLITE_STATUS_MALLOC_SIZE 5 7097#define SQLITE_STATUS_PARSER_STACK 6 7098#define SQLITE_STATUS_PAGECACHE_SIZE 7 7099#define SQLITE_STATUS_SCRATCH_SIZE 8 7100#define SQLITE_STATUS_MALLOC_COUNT 9 7101 7102/* 7103** CAPI3REF: Database Connection Status 7104** METHOD: sqlite3 7105** 7106** ^This interface is used to retrieve runtime status information 7107** about a single [database connection]. ^The first argument is the 7108** database connection object to be interrogated. ^The second argument 7109** is an integer constant, taken from the set of 7110** [SQLITE_DBSTATUS options], that 7111** determines the parameter to interrogate. The set of 7112** [SQLITE_DBSTATUS options] is likely 7113** to grow in future releases of SQLite. 7114** 7115** ^The current value of the requested parameter is written into *pCur 7116** and the highest instantaneous value is written into *pHiwtr. ^If 7117** the resetFlg is true, then the highest instantaneous value is 7118** reset back down to the current value. 7119** 7120** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 7121** non-zero [error code] on failure. 7122** 7123** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 7124*/ 7125int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 7126 7127/* 7128** CAPI3REF: Status Parameters for database connections 7129** KEYWORDS: {SQLITE_DBSTATUS options} 7130** 7131** These constants are the available integer "verbs" that can be passed as 7132** the second argument to the [sqlite3_db_status()] interface. 7133** 7134** New verbs may be added in future releases of SQLite. Existing verbs 7135** might be discontinued. Applications should check the return code from 7136** [sqlite3_db_status()] to make sure that the call worked. 7137** The [sqlite3_db_status()] interface will return a non-zero error code 7138** if a discontinued or unsupported verb is invoked. 7139** 7140** <dl> 7141** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 7142** <dd>This parameter returns the number of lookaside memory slots currently 7143** checked out.</dd>)^ 7144** 7145** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 7146** <dd>This parameter returns the number malloc attempts that were 7147** satisfied using lookaside memory. Only the high-water value is meaningful; 7148** the current value is always zero.)^ 7149** 7150** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 7151** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 7152** <dd>This parameter returns the number malloc attempts that might have 7153** been satisfied using lookaside memory but failed due to the amount of 7154** memory requested being larger than the lookaside slot size. 7155** Only the high-water value is meaningful; 7156** the current value is always zero.)^ 7157** 7158** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 7159** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 7160** <dd>This parameter returns the number malloc attempts that might have 7161** been satisfied using lookaside memory but failed due to all lookaside 7162** memory already being in use. 7163** Only the high-water value is meaningful; 7164** the current value is always zero.)^ 7165** 7166** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 7167** <dd>This parameter returns the approximate number of bytes of heap 7168** memory used by all pager caches associated with the database connection.)^ 7169** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 7170** 7171** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 7172** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 7173** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 7174** pager cache is shared between two or more connections the bytes of heap 7175** memory used by that pager cache is divided evenly between the attached 7176** connections.)^ In other words, if none of the pager caches associated 7177** with the database connection are shared, this request returns the same 7178** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 7179** shared, the value returned by this call will be smaller than that returned 7180** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 7181** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 7182** 7183** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 7184** <dd>This parameter returns the approximate number of bytes of heap 7185** memory used to store the schema for all databases associated 7186** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 7187** ^The full amount of memory used by the schemas is reported, even if the 7188** schema memory is shared with other database connections due to 7189** [shared cache mode] being enabled. 7190** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 7191** 7192** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 7193** <dd>This parameter returns the approximate number of bytes of heap 7194** and lookaside memory used by all prepared statements associated with 7195** the database connection.)^ 7196** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 7197** </dd> 7198** 7199** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 7200** <dd>This parameter returns the number of pager cache hits that have 7201** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 7202** is always 0. 7203** </dd> 7204** 7205** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 7206** <dd>This parameter returns the number of pager cache misses that have 7207** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 7208** is always 0. 7209** </dd> 7210** 7211** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 7212** <dd>This parameter returns the number of dirty cache entries that have 7213** been written to disk. Specifically, the number of pages written to the 7214** wal file in wal mode databases, or the number of pages written to the 7215** database file in rollback mode databases. Any pages written as part of 7216** transaction rollback or database recovery operations are not included. 7217** If an IO or other error occurs while writing a page to disk, the effect 7218** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 7219** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 7220** </dd> 7221** 7222** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 7223** <dd>This parameter returns zero for the current value if and only if 7224** all foreign key constraints (deferred or immediate) have been 7225** resolved.)^ ^The highwater mark is always 0. 7226** </dd> 7227** </dl> 7228*/ 7229#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 7230#define SQLITE_DBSTATUS_CACHE_USED 1 7231#define SQLITE_DBSTATUS_SCHEMA_USED 2 7232#define SQLITE_DBSTATUS_STMT_USED 3 7233#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 7234#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 7235#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 7236#define SQLITE_DBSTATUS_CACHE_HIT 7 7237#define SQLITE_DBSTATUS_CACHE_MISS 8 7238#define SQLITE_DBSTATUS_CACHE_WRITE 9 7239#define SQLITE_DBSTATUS_DEFERRED_FKS 10 7240#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 7241#define SQLITE_DBSTATUS_MAX 11 /* Largest defined DBSTATUS */ 7242 7243 7244/* 7245** CAPI3REF: Prepared Statement Status 7246** METHOD: sqlite3_stmt 7247** 7248** ^(Each prepared statement maintains various 7249** [SQLITE_STMTSTATUS counters] that measure the number 7250** of times it has performed specific operations.)^ These counters can 7251** be used to monitor the performance characteristics of the prepared 7252** statements. For example, if the number of table steps greatly exceeds 7253** the number of table searches or result rows, that would tend to indicate 7254** that the prepared statement is using a full table scan rather than 7255** an index. 7256** 7257** ^(This interface is used to retrieve and reset counter values from 7258** a [prepared statement]. The first argument is the prepared statement 7259** object to be interrogated. The second argument 7260** is an integer code for a specific [SQLITE_STMTSTATUS counter] 7261** to be interrogated.)^ 7262** ^The current value of the requested counter is returned. 7263** ^If the resetFlg is true, then the counter is reset to zero after this 7264** interface call returns. 7265** 7266** See also: [sqlite3_status()] and [sqlite3_db_status()]. 7267*/ 7268int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 7269 7270/* 7271** CAPI3REF: Status Parameters for prepared statements 7272** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 7273** 7274** These preprocessor macros define integer codes that name counter 7275** values associated with the [sqlite3_stmt_status()] interface. 7276** The meanings of the various counters are as follows: 7277** 7278** <dl> 7279** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 7280** <dd>^This is the number of times that SQLite has stepped forward in 7281** a table as part of a full table scan. Large numbers for this counter 7282** may indicate opportunities for performance improvement through 7283** careful use of indices.</dd> 7284** 7285** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 7286** <dd>^This is the number of sort operations that have occurred. 7287** A non-zero value in this counter may indicate an opportunity to 7288** improvement performance through careful use of indices.</dd> 7289** 7290** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 7291** <dd>^This is the number of rows inserted into transient indices that 7292** were created automatically in order to help joins run faster. 7293** A non-zero value in this counter may indicate an opportunity to 7294** improvement performance by adding permanent indices that do not 7295** need to be reinitialized each time the statement is run.</dd> 7296** 7297** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 7298** <dd>^This is the number of virtual machine operations executed 7299** by the prepared statement if that number is less than or equal 7300** to 2147483647. The number of virtual machine operations can be 7301** used as a proxy for the total work done by the prepared statement. 7302** If the number of virtual machine operations exceeds 2147483647 7303** then the value returned by this statement status code is undefined. 7304** 7305** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 7306** <dd>^This is the number of times that the prepare statement has been 7307** automatically regenerated due to schema changes or change to 7308** [bound parameters] that might affect the query plan. 7309** 7310** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 7311** <dd>^This is the number of times that the prepared statement has 7312** been run. A single "run" for the purposes of this counter is one 7313** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 7314** The counter is incremented on the first [sqlite3_step()] call of each 7315** cycle. 7316** 7317** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 7318** <dd>^This is the approximate number of bytes of heap memory 7319** used to store the prepared statement. ^This value is not actually 7320** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 7321** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 7322** </dd> 7323** </dl> 7324*/ 7325#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 7326#define SQLITE_STMTSTATUS_SORT 2 7327#define SQLITE_STMTSTATUS_AUTOINDEX 3 7328#define SQLITE_STMTSTATUS_VM_STEP 4 7329#define SQLITE_STMTSTATUS_REPREPARE 5 7330#define SQLITE_STMTSTATUS_RUN 6 7331#define SQLITE_STMTSTATUS_MEMUSED 99 7332 7333/* 7334** CAPI3REF: Custom Page Cache Object 7335** 7336** The sqlite3_pcache type is opaque. It is implemented by 7337** the pluggable module. The SQLite core has no knowledge of 7338** its size or internal structure and never deals with the 7339** sqlite3_pcache object except by holding and passing pointers 7340** to the object. 7341** 7342** See [sqlite3_pcache_methods2] for additional information. 7343*/ 7344typedef struct sqlite3_pcache sqlite3_pcache; 7345 7346/* 7347** CAPI3REF: Custom Page Cache Object 7348** 7349** The sqlite3_pcache_page object represents a single page in the 7350** page cache. The page cache will allocate instances of this 7351** object. Various methods of the page cache use pointers to instances 7352** of this object as parameters or as their return value. 7353** 7354** See [sqlite3_pcache_methods2] for additional information. 7355*/ 7356typedef struct sqlite3_pcache_page sqlite3_pcache_page; 7357struct sqlite3_pcache_page { 7358 void *pBuf; /* The content of the page */ 7359 void *pExtra; /* Extra information associated with the page */ 7360}; 7361 7362/* 7363** CAPI3REF: Application Defined Page Cache. 7364** KEYWORDS: {page cache} 7365** 7366** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 7367** register an alternative page cache implementation by passing in an 7368** instance of the sqlite3_pcache_methods2 structure.)^ 7369** In many applications, most of the heap memory allocated by 7370** SQLite is used for the page cache. 7371** By implementing a 7372** custom page cache using this API, an application can better control 7373** the amount of memory consumed by SQLite, the way in which 7374** that memory is allocated and released, and the policies used to 7375** determine exactly which parts of a database file are cached and for 7376** how long. 7377** 7378** The alternative page cache mechanism is an 7379** extreme measure that is only needed by the most demanding applications. 7380** The built-in page cache is recommended for most uses. 7381** 7382** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 7383** internal buffer by SQLite within the call to [sqlite3_config]. Hence 7384** the application may discard the parameter after the call to 7385** [sqlite3_config()] returns.)^ 7386** 7387** [[the xInit() page cache method]] 7388** ^(The xInit() method is called once for each effective 7389** call to [sqlite3_initialize()])^ 7390** (usually only once during the lifetime of the process). ^(The xInit() 7391** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 7392** The intent of the xInit() method is to set up global data structures 7393** required by the custom page cache implementation. 7394** ^(If the xInit() method is NULL, then the 7395** built-in default page cache is used instead of the application defined 7396** page cache.)^ 7397** 7398** [[the xShutdown() page cache method]] 7399** ^The xShutdown() method is called by [sqlite3_shutdown()]. 7400** It can be used to clean up 7401** any outstanding resources before process shutdown, if required. 7402** ^The xShutdown() method may be NULL. 7403** 7404** ^SQLite automatically serializes calls to the xInit method, 7405** so the xInit method need not be threadsafe. ^The 7406** xShutdown method is only called from [sqlite3_shutdown()] so it does 7407** not need to be threadsafe either. All other methods must be threadsafe 7408** in multithreaded applications. 7409** 7410** ^SQLite will never invoke xInit() more than once without an intervening 7411** call to xShutdown(). 7412** 7413** [[the xCreate() page cache methods]] 7414** ^SQLite invokes the xCreate() method to construct a new cache instance. 7415** SQLite will typically create one cache instance for each open database file, 7416** though this is not guaranteed. ^The 7417** first parameter, szPage, is the size in bytes of the pages that must 7418** be allocated by the cache. ^szPage will always a power of two. ^The 7419** second parameter szExtra is a number of bytes of extra storage 7420** associated with each page cache entry. ^The szExtra parameter will 7421** a number less than 250. SQLite will use the 7422** extra szExtra bytes on each page to store metadata about the underlying 7423** database page on disk. The value passed into szExtra depends 7424** on the SQLite version, the target platform, and how SQLite was compiled. 7425** ^The third argument to xCreate(), bPurgeable, is true if the cache being 7426** created will be used to cache database pages of a file stored on disk, or 7427** false if it is used for an in-memory database. The cache implementation 7428** does not have to do anything special based with the value of bPurgeable; 7429** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 7430** never invoke xUnpin() except to deliberately delete a page. 7431** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 7432** false will always have the "discard" flag set to true. 7433** ^Hence, a cache created with bPurgeable false will 7434** never contain any unpinned pages. 7435** 7436** [[the xCachesize() page cache method]] 7437** ^(The xCachesize() method may be called at any time by SQLite to set the 7438** suggested maximum cache-size (number of pages stored by) the cache 7439** instance passed as the first argument. This is the value configured using 7440** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 7441** parameter, the implementation is not required to do anything with this 7442** value; it is advisory only. 7443** 7444** [[the xPagecount() page cache methods]] 7445** The xPagecount() method must return the number of pages currently 7446** stored in the cache, both pinned and unpinned. 7447** 7448** [[the xFetch() page cache methods]] 7449** The xFetch() method locates a page in the cache and returns a pointer to 7450** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 7451** The pBuf element of the returned sqlite3_pcache_page object will be a 7452** pointer to a buffer of szPage bytes used to store the content of a 7453** single database page. The pExtra element of sqlite3_pcache_page will be 7454** a pointer to the szExtra bytes of extra storage that SQLite has requested 7455** for each entry in the page cache. 7456** 7457** The page to be fetched is determined by the key. ^The minimum key value 7458** is 1. After it has been retrieved using xFetch, the page is considered 7459** to be "pinned". 7460** 7461** If the requested page is already in the page cache, then the page cache 7462** implementation must return a pointer to the page buffer with its content 7463** intact. If the requested page is not already in the cache, then the 7464** cache implementation should use the value of the createFlag 7465** parameter to help it determined what action to take: 7466** 7467** <table border=1 width=85% align=center> 7468** <tr><th> createFlag <th> Behavior when page is not already in cache 7469** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 7470** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 7471** Otherwise return NULL. 7472** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 7473** NULL if allocating a new page is effectively impossible. 7474** </table> 7475** 7476** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 7477** will only use a createFlag of 2 after a prior call with a createFlag of 1 7478** failed.)^ In between the to xFetch() calls, SQLite may 7479** attempt to unpin one or more cache pages by spilling the content of 7480** pinned pages to disk and synching the operating system disk cache. 7481** 7482** [[the xUnpin() page cache method]] 7483** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 7484** as its second argument. If the third parameter, discard, is non-zero, 7485** then the page must be evicted from the cache. 7486** ^If the discard parameter is 7487** zero, then the page may be discarded or retained at the discretion of 7488** page cache implementation. ^The page cache implementation 7489** may choose to evict unpinned pages at any time. 7490** 7491** The cache must not perform any reference counting. A single 7492** call to xUnpin() unpins the page regardless of the number of prior calls 7493** to xFetch(). 7494** 7495** [[the xRekey() page cache methods]] 7496** The xRekey() method is used to change the key value associated with the 7497** page passed as the second argument. If the cache 7498** previously contains an entry associated with newKey, it must be 7499** discarded. ^Any prior cache entry associated with newKey is guaranteed not 7500** to be pinned. 7501** 7502** When SQLite calls the xTruncate() method, the cache must discard all 7503** existing cache entries with page numbers (keys) greater than or equal 7504** to the value of the iLimit parameter passed to xTruncate(). If any 7505** of these pages are pinned, they are implicitly unpinned, meaning that 7506** they can be safely discarded. 7507** 7508** [[the xDestroy() page cache method]] 7509** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 7510** All resources associated with the specified cache should be freed. ^After 7511** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 7512** handle invalid, and will not use it with any other sqlite3_pcache_methods2 7513** functions. 7514** 7515** [[the xShrink() page cache method]] 7516** ^SQLite invokes the xShrink() method when it wants the page cache to 7517** free up as much of heap memory as possible. The page cache implementation 7518** is not obligated to free any memory, but well-behaved implementations should 7519** do their best. 7520*/ 7521typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 7522struct sqlite3_pcache_methods2 { 7523 int iVersion; 7524 void *pArg; 7525 int (*xInit)(void*); 7526 void (*xShutdown)(void*); 7527 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 7528 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7529 int (*xPagecount)(sqlite3_pcache*); 7530 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7531 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 7532 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 7533 unsigned oldKey, unsigned newKey); 7534 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7535 void (*xDestroy)(sqlite3_pcache*); 7536 void (*xShrink)(sqlite3_pcache*); 7537}; 7538 7539/* 7540** This is the obsolete pcache_methods object that has now been replaced 7541** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 7542** retained in the header file for backwards compatibility only. 7543*/ 7544typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 7545struct sqlite3_pcache_methods { 7546 void *pArg; 7547 int (*xInit)(void*); 7548 void (*xShutdown)(void*); 7549 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 7550 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7551 int (*xPagecount)(sqlite3_pcache*); 7552 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7553 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 7554 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 7555 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7556 void (*xDestroy)(sqlite3_pcache*); 7557}; 7558 7559 7560/* 7561** CAPI3REF: Online Backup Object 7562** 7563** The sqlite3_backup object records state information about an ongoing 7564** online backup operation. ^The sqlite3_backup object is created by 7565** a call to [sqlite3_backup_init()] and is destroyed by a call to 7566** [sqlite3_backup_finish()]. 7567** 7568** See Also: [Using the SQLite Online Backup API] 7569*/ 7570typedef struct sqlite3_backup sqlite3_backup; 7571 7572/* 7573** CAPI3REF: Online Backup API. 7574** 7575** The backup API copies the content of one database into another. 7576** It is useful either for creating backups of databases or 7577** for copying in-memory databases to or from persistent files. 7578** 7579** See Also: [Using the SQLite Online Backup API] 7580** 7581** ^SQLite holds a write transaction open on the destination database file 7582** for the duration of the backup operation. 7583** ^The source database is read-locked only while it is being read; 7584** it is not locked continuously for the entire backup operation. 7585** ^Thus, the backup may be performed on a live source database without 7586** preventing other database connections from 7587** reading or writing to the source database while the backup is underway. 7588** 7589** ^(To perform a backup operation: 7590** <ol> 7591** <li><b>sqlite3_backup_init()</b> is called once to initialize the 7592** backup, 7593** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 7594** the data between the two databases, and finally 7595** <li><b>sqlite3_backup_finish()</b> is called to release all resources 7596** associated with the backup operation. 7597** </ol>)^ 7598** There should be exactly one call to sqlite3_backup_finish() for each 7599** successful call to sqlite3_backup_init(). 7600** 7601** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 7602** 7603** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 7604** [database connection] associated with the destination database 7605** and the database name, respectively. 7606** ^The database name is "main" for the main database, "temp" for the 7607** temporary database, or the name specified after the AS keyword in 7608** an [ATTACH] statement for an attached database. 7609** ^The S and M arguments passed to 7610** sqlite3_backup_init(D,N,S,M) identify the [database connection] 7611** and database name of the source database, respectively. 7612** ^The source and destination [database connections] (parameters S and D) 7613** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 7614** an error. 7615** 7616** ^A call to sqlite3_backup_init() will fail, returning NULL, if 7617** there is already a read or read-write transaction open on the 7618** destination database. 7619** 7620** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 7621** returned and an error code and error message are stored in the 7622** destination [database connection] D. 7623** ^The error code and message for the failed call to sqlite3_backup_init() 7624** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 7625** [sqlite3_errmsg16()] functions. 7626** ^A successful call to sqlite3_backup_init() returns a pointer to an 7627** [sqlite3_backup] object. 7628** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 7629** sqlite3_backup_finish() functions to perform the specified backup 7630** operation. 7631** 7632** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 7633** 7634** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 7635** the source and destination databases specified by [sqlite3_backup] object B. 7636** ^If N is negative, all remaining source pages are copied. 7637** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 7638** are still more pages to be copied, then the function returns [SQLITE_OK]. 7639** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 7640** from source to destination, then it returns [SQLITE_DONE]. 7641** ^If an error occurs while running sqlite3_backup_step(B,N), 7642** then an [error code] is returned. ^As well as [SQLITE_OK] and 7643** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 7644** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 7645** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 7646** 7647** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 7648** <ol> 7649** <li> the destination database was opened read-only, or 7650** <li> the destination database is using write-ahead-log journaling 7651** and the destination and source page sizes differ, or 7652** <li> the destination database is an in-memory database and the 7653** destination and source page sizes differ. 7654** </ol>)^ 7655** 7656** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 7657** the [sqlite3_busy_handler | busy-handler function] 7658** is invoked (if one is specified). ^If the 7659** busy-handler returns non-zero before the lock is available, then 7660** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 7661** sqlite3_backup_step() can be retried later. ^If the source 7662** [database connection] 7663** is being used to write to the source database when sqlite3_backup_step() 7664** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 7665** case the call to sqlite3_backup_step() can be retried later on. ^(If 7666** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 7667** [SQLITE_READONLY] is returned, then 7668** there is no point in retrying the call to sqlite3_backup_step(). These 7669** errors are considered fatal.)^ The application must accept 7670** that the backup operation has failed and pass the backup operation handle 7671** to the sqlite3_backup_finish() to release associated resources. 7672** 7673** ^The first call to sqlite3_backup_step() obtains an exclusive lock 7674** on the destination file. ^The exclusive lock is not released until either 7675** sqlite3_backup_finish() is called or the backup operation is complete 7676** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 7677** sqlite3_backup_step() obtains a [shared lock] on the source database that 7678** lasts for the duration of the sqlite3_backup_step() call. 7679** ^Because the source database is not locked between calls to 7680** sqlite3_backup_step(), the source database may be modified mid-way 7681** through the backup process. ^If the source database is modified by an 7682** external process or via a database connection other than the one being 7683** used by the backup operation, then the backup will be automatically 7684** restarted by the next call to sqlite3_backup_step(). ^If the source 7685** database is modified by the using the same database connection as is used 7686** by the backup operation, then the backup database is automatically 7687** updated at the same time. 7688** 7689** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 7690** 7691** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 7692** application wishes to abandon the backup operation, the application 7693** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 7694** ^The sqlite3_backup_finish() interfaces releases all 7695** resources associated with the [sqlite3_backup] object. 7696** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 7697** active write-transaction on the destination database is rolled back. 7698** The [sqlite3_backup] object is invalid 7699** and may not be used following a call to sqlite3_backup_finish(). 7700** 7701** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 7702** sqlite3_backup_step() errors occurred, regardless or whether or not 7703** sqlite3_backup_step() completed. 7704** ^If an out-of-memory condition or IO error occurred during any prior 7705** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 7706** sqlite3_backup_finish() returns the corresponding [error code]. 7707** 7708** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 7709** is not a permanent error and does not affect the return value of 7710** sqlite3_backup_finish(). 7711** 7712** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 7713** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 7714** 7715** ^The sqlite3_backup_remaining() routine returns the number of pages still 7716** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 7717** ^The sqlite3_backup_pagecount() routine returns the total number of pages 7718** in the source database at the conclusion of the most recent 7719** sqlite3_backup_step(). 7720** ^(The values returned by these functions are only updated by 7721** sqlite3_backup_step(). If the source database is modified in a way that 7722** changes the size of the source database or the number of pages remaining, 7723** those changes are not reflected in the output of sqlite3_backup_pagecount() 7724** and sqlite3_backup_remaining() until after the next 7725** sqlite3_backup_step().)^ 7726** 7727** <b>Concurrent Usage of Database Handles</b> 7728** 7729** ^The source [database connection] may be used by the application for other 7730** purposes while a backup operation is underway or being initialized. 7731** ^If SQLite is compiled and configured to support threadsafe database 7732** connections, then the source database connection may be used concurrently 7733** from within other threads. 7734** 7735** However, the application must guarantee that the destination 7736** [database connection] is not passed to any other API (by any thread) after 7737** sqlite3_backup_init() is called and before the corresponding call to 7738** sqlite3_backup_finish(). SQLite does not currently check to see 7739** if the application incorrectly accesses the destination [database connection] 7740** and so no error code is reported, but the operations may malfunction 7741** nevertheless. Use of the destination database connection while a 7742** backup is in progress might also also cause a mutex deadlock. 7743** 7744** If running in [shared cache mode], the application must 7745** guarantee that the shared cache used by the destination database 7746** is not accessed while the backup is running. In practice this means 7747** that the application must guarantee that the disk file being 7748** backed up to is not accessed by any connection within the process, 7749** not just the specific connection that was passed to sqlite3_backup_init(). 7750** 7751** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7752** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7753** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7754** APIs are not strictly speaking threadsafe. If they are invoked at the 7755** same time as another thread is invoking sqlite3_backup_step() it is 7756** possible that they return invalid values. 7757*/ 7758sqlite3_backup *sqlite3_backup_init( 7759 sqlite3 *pDest, /* Destination database handle */ 7760 const char *zDestName, /* Destination database name */ 7761 sqlite3 *pSource, /* Source database handle */ 7762 const char *zSourceName /* Source database name */ 7763); 7764int sqlite3_backup_step(sqlite3_backup *p, int nPage); 7765int sqlite3_backup_finish(sqlite3_backup *p); 7766int sqlite3_backup_remaining(sqlite3_backup *p); 7767int sqlite3_backup_pagecount(sqlite3_backup *p); 7768 7769/* 7770** CAPI3REF: Unlock Notification 7771** METHOD: sqlite3 7772** 7773** ^When running in shared-cache mode, a database operation may fail with 7774** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7775** individual tables within the shared-cache cannot be obtained. See 7776** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7777** ^This API may be used to register a callback that SQLite will invoke 7778** when the connection currently holding the required lock relinquishes it. 7779** ^This API is only available if the library was compiled with the 7780** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7781** 7782** See Also: [Using the SQLite Unlock Notification Feature]. 7783** 7784** ^Shared-cache locks are released when a database connection concludes 7785** its current transaction, either by committing it or rolling it back. 7786** 7787** ^When a connection (known as the blocked connection) fails to obtain a 7788** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7789** identity of the database connection (the blocking connection) that 7790** has locked the required resource is stored internally. ^After an 7791** application receives an SQLITE_LOCKED error, it may call the 7792** sqlite3_unlock_notify() method with the blocked connection handle as 7793** the first argument to register for a callback that will be invoked 7794** when the blocking connections current transaction is concluded. ^The 7795** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7796** call that concludes the blocking connections transaction. 7797** 7798** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7799** there is a chance that the blocking connection will have already 7800** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7801** If this happens, then the specified callback is invoked immediately, 7802** from within the call to sqlite3_unlock_notify().)^ 7803** 7804** ^If the blocked connection is attempting to obtain a write-lock on a 7805** shared-cache table, and more than one other connection currently holds 7806** a read-lock on the same table, then SQLite arbitrarily selects one of 7807** the other connections to use as the blocking connection. 7808** 7809** ^(There may be at most one unlock-notify callback registered by a 7810** blocked connection. If sqlite3_unlock_notify() is called when the 7811** blocked connection already has a registered unlock-notify callback, 7812** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7813** called with a NULL pointer as its second argument, then any existing 7814** unlock-notify callback is canceled. ^The blocked connections 7815** unlock-notify callback may also be canceled by closing the blocked 7816** connection using [sqlite3_close()]. 7817** 7818** The unlock-notify callback is not reentrant. If an application invokes 7819** any sqlite3_xxx API functions from within an unlock-notify callback, a 7820** crash or deadlock may be the result. 7821** 7822** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7823** returns SQLITE_OK. 7824** 7825** <b>Callback Invocation Details</b> 7826** 7827** When an unlock-notify callback is registered, the application provides a 7828** single void* pointer that is passed to the callback when it is invoked. 7829** However, the signature of the callback function allows SQLite to pass 7830** it an array of void* context pointers. The first argument passed to 7831** an unlock-notify callback is a pointer to an array of void* pointers, 7832** and the second is the number of entries in the array. 7833** 7834** When a blocking connections transaction is concluded, there may be 7835** more than one blocked connection that has registered for an unlock-notify 7836** callback. ^If two or more such blocked connections have specified the 7837** same callback function, then instead of invoking the callback function 7838** multiple times, it is invoked once with the set of void* context pointers 7839** specified by the blocked connections bundled together into an array. 7840** This gives the application an opportunity to prioritize any actions 7841** related to the set of unblocked database connections. 7842** 7843** <b>Deadlock Detection</b> 7844** 7845** Assuming that after registering for an unlock-notify callback a 7846** database waits for the callback to be issued before taking any further 7847** action (a reasonable assumption), then using this API may cause the 7848** application to deadlock. For example, if connection X is waiting for 7849** connection Y's transaction to be concluded, and similarly connection 7850** Y is waiting on connection X's transaction, then neither connection 7851** will proceed and the system may remain deadlocked indefinitely. 7852** 7853** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7854** detection. ^If a given call to sqlite3_unlock_notify() would put the 7855** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7856** unlock-notify callback is registered. The system is said to be in 7857** a deadlocked state if connection A has registered for an unlock-notify 7858** callback on the conclusion of connection B's transaction, and connection 7859** B has itself registered for an unlock-notify callback when connection 7860** A's transaction is concluded. ^Indirect deadlock is also detected, so 7861** the system is also considered to be deadlocked if connection B has 7862** registered for an unlock-notify callback on the conclusion of connection 7863** C's transaction, where connection C is waiting on connection A. ^Any 7864** number of levels of indirection are allowed. 7865** 7866** <b>The "DROP TABLE" Exception</b> 7867** 7868** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7869** always appropriate to call sqlite3_unlock_notify(). There is however, 7870** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7871** SQLite checks if there are any currently executing SELECT statements 7872** that belong to the same connection. If there are, SQLITE_LOCKED is 7873** returned. In this case there is no "blocking connection", so invoking 7874** sqlite3_unlock_notify() results in the unlock-notify callback being 7875** invoked immediately. If the application then re-attempts the "DROP TABLE" 7876** or "DROP INDEX" query, an infinite loop might be the result. 7877** 7878** One way around this problem is to check the extended error code returned 7879** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7880** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7881** the special "DROP TABLE/INDEX" case, the extended error code is just 7882** SQLITE_LOCKED.)^ 7883*/ 7884int sqlite3_unlock_notify( 7885 sqlite3 *pBlocked, /* Waiting connection */ 7886 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7887 void *pNotifyArg /* Argument to pass to xNotify */ 7888); 7889 7890 7891/* 7892** CAPI3REF: String Comparison 7893** 7894** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7895** and extensions to compare the contents of two buffers containing UTF-8 7896** strings in a case-independent fashion, using the same definition of "case 7897** independence" that SQLite uses internally when comparing identifiers. 7898*/ 7899int sqlite3_stricmp(const char *, const char *); 7900int sqlite3_strnicmp(const char *, const char *, int); 7901 7902/* 7903** CAPI3REF: String Globbing 7904* 7905** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 7906** string X matches the [GLOB] pattern P. 7907** ^The definition of [GLOB] pattern matching used in 7908** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7909** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 7910** is case sensitive. 7911** 7912** Note that this routine returns zero on a match and non-zero if the strings 7913** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7914** 7915** See also: [sqlite3_strlike()]. 7916*/ 7917int sqlite3_strglob(const char *zGlob, const char *zStr); 7918 7919/* 7920** CAPI3REF: String LIKE Matching 7921* 7922** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 7923** string X matches the [LIKE] pattern P with escape character E. 7924** ^The definition of [LIKE] pattern matching used in 7925** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 7926** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 7927** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 7928** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 7929** insensitive - equivalent upper and lower case ASCII characters match 7930** one another. 7931** 7932** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 7933** only ASCII characters are case folded. 7934** 7935** Note that this routine returns zero on a match and non-zero if the strings 7936** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7937** 7938** See also: [sqlite3_strglob()]. 7939*/ 7940int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 7941 7942/* 7943** CAPI3REF: Error Logging Interface 7944** 7945** ^The [sqlite3_log()] interface writes a message into the [error log] 7946** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7947** ^If logging is enabled, the zFormat string and subsequent arguments are 7948** used with [sqlite3_snprintf()] to generate the final output string. 7949** 7950** The sqlite3_log() interface is intended for use by extensions such as 7951** virtual tables, collating functions, and SQL functions. While there is 7952** nothing to prevent an application from calling sqlite3_log(), doing so 7953** is considered bad form. 7954** 7955** The zFormat string must not be NULL. 7956** 7957** To avoid deadlocks and other threading problems, the sqlite3_log() routine 7958** will not use dynamically allocated memory. The log message is stored in 7959** a fixed-length buffer on the stack. If the log message is longer than 7960** a few hundred characters, it will be truncated to the length of the 7961** buffer. 7962*/ 7963void sqlite3_log(int iErrCode, const char *zFormat, ...); 7964 7965/* 7966** CAPI3REF: Write-Ahead Log Commit Hook 7967** METHOD: sqlite3 7968** 7969** ^The [sqlite3_wal_hook()] function is used to register a callback that 7970** is invoked each time data is committed to a database in wal mode. 7971** 7972** ^(The callback is invoked by SQLite after the commit has taken place and 7973** the associated write-lock on the database released)^, so the implementation 7974** may read, write or [checkpoint] the database as required. 7975** 7976** ^The first parameter passed to the callback function when it is invoked 7977** is a copy of the third parameter passed to sqlite3_wal_hook() when 7978** registering the callback. ^The second is a copy of the database handle. 7979** ^The third parameter is the name of the database that was written to - 7980** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 7981** is the number of pages currently in the write-ahead log file, 7982** including those that were just committed. 7983** 7984** The callback function should normally return [SQLITE_OK]. ^If an error 7985** code is returned, that error will propagate back up through the 7986** SQLite code base to cause the statement that provoked the callback 7987** to report an error, though the commit will have still occurred. If the 7988** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 7989** that does not correspond to any valid SQLite error code, the results 7990** are undefined. 7991** 7992** A single database handle may have at most a single write-ahead log callback 7993** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 7994** previously registered write-ahead log callback. ^Note that the 7995** [sqlite3_wal_autocheckpoint()] interface and the 7996** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 7997** overwrite any prior [sqlite3_wal_hook()] settings. 7998*/ 7999void *sqlite3_wal_hook( 8000 sqlite3*, 8001 int(*)(void *,sqlite3*,const char*,int), 8002 void* 8003); 8004 8005/* 8006** CAPI3REF: Configure an auto-checkpoint 8007** METHOD: sqlite3 8008** 8009** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 8010** [sqlite3_wal_hook()] that causes any database on [database connection] D 8011** to automatically [checkpoint] 8012** after committing a transaction if there are N or 8013** more frames in the [write-ahead log] file. ^Passing zero or 8014** a negative value as the nFrame parameter disables automatic 8015** checkpoints entirely. 8016** 8017** ^The callback registered by this function replaces any existing callback 8018** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 8019** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 8020** configured by this function. 8021** 8022** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 8023** from SQL. 8024** 8025** ^Checkpoints initiated by this mechanism are 8026** [sqlite3_wal_checkpoint_v2|PASSIVE]. 8027** 8028** ^Every new [database connection] defaults to having the auto-checkpoint 8029** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 8030** pages. The use of this interface 8031** is only necessary if the default setting is found to be suboptimal 8032** for a particular application. 8033*/ 8034int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 8035 8036/* 8037** CAPI3REF: Checkpoint a database 8038** METHOD: sqlite3 8039** 8040** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 8041** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 8042** 8043** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 8044** [write-ahead log] for database X on [database connection] D to be 8045** transferred into the database file and for the write-ahead log to 8046** be reset. See the [checkpointing] documentation for addition 8047** information. 8048** 8049** This interface used to be the only way to cause a checkpoint to 8050** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 8051** interface was added. This interface is retained for backwards 8052** compatibility and as a convenience for applications that need to manually 8053** start a callback but which do not need the full power (and corresponding 8054** complication) of [sqlite3_wal_checkpoint_v2()]. 8055*/ 8056int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 8057 8058/* 8059** CAPI3REF: Checkpoint a database 8060** METHOD: sqlite3 8061** 8062** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 8063** operation on database X of [database connection] D in mode M. Status 8064** information is written back into integers pointed to by L and C.)^ 8065** ^(The M parameter must be a valid [checkpoint mode]:)^ 8066** 8067** <dl> 8068** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 8069** ^Checkpoint as many frames as possible without waiting for any database 8070** readers or writers to finish, then sync the database file if all frames 8071** in the log were checkpointed. ^The [busy-handler callback] 8072** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 8073** ^On the other hand, passive mode might leave the checkpoint unfinished 8074** if there are concurrent readers or writers. 8075** 8076** <dt>SQLITE_CHECKPOINT_FULL<dd> 8077** ^This mode blocks (it invokes the 8078** [sqlite3_busy_handler|busy-handler callback]) until there is no 8079** database writer and all readers are reading from the most recent database 8080** snapshot. ^It then checkpoints all frames in the log file and syncs the 8081** database file. ^This mode blocks new database writers while it is pending, 8082** but new database readers are allowed to continue unimpeded. 8083** 8084** <dt>SQLITE_CHECKPOINT_RESTART<dd> 8085** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 8086** that after checkpointing the log file it blocks (calls the 8087** [busy-handler callback]) 8088** until all readers are reading from the database file only. ^This ensures 8089** that the next writer will restart the log file from the beginning. 8090** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 8091** database writer attempts while it is pending, but does not impede readers. 8092** 8093** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 8094** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 8095** addition that it also truncates the log file to zero bytes just prior 8096** to a successful return. 8097** </dl> 8098** 8099** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 8100** the log file or to -1 if the checkpoint could not run because 8101** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 8102** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 8103** log file (including any that were already checkpointed before the function 8104** was called) or to -1 if the checkpoint could not run due to an error or 8105** because the database is not in WAL mode. ^Note that upon successful 8106** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 8107** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 8108** 8109** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 8110** any other process is running a checkpoint operation at the same time, the 8111** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 8112** busy-handler configured, it will not be invoked in this case. 8113** 8114** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 8115** exclusive "writer" lock on the database file. ^If the writer lock cannot be 8116** obtained immediately, and a busy-handler is configured, it is invoked and 8117** the writer lock retried until either the busy-handler returns 0 or the lock 8118** is successfully obtained. ^The busy-handler is also invoked while waiting for 8119** database readers as described above. ^If the busy-handler returns 0 before 8120** the writer lock is obtained or while waiting for database readers, the 8121** checkpoint operation proceeds from that point in the same way as 8122** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 8123** without blocking any further. ^SQLITE_BUSY is returned in this case. 8124** 8125** ^If parameter zDb is NULL or points to a zero length string, then the 8126** specified operation is attempted on all WAL databases [attached] to 8127** [database connection] db. In this case the 8128** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 8129** an SQLITE_BUSY error is encountered when processing one or more of the 8130** attached WAL databases, the operation is still attempted on any remaining 8131** attached databases and SQLITE_BUSY is returned at the end. ^If any other 8132** error occurs while processing an attached database, processing is abandoned 8133** and the error code is returned to the caller immediately. ^If no error 8134** (SQLITE_BUSY or otherwise) is encountered while processing the attached 8135** databases, SQLITE_OK is returned. 8136** 8137** ^If database zDb is the name of an attached database that is not in WAL 8138** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 8139** zDb is not NULL (or a zero length string) and is not the name of any 8140** attached database, SQLITE_ERROR is returned to the caller. 8141** 8142** ^Unless it returns SQLITE_MISUSE, 8143** the sqlite3_wal_checkpoint_v2() interface 8144** sets the error information that is queried by 8145** [sqlite3_errcode()] and [sqlite3_errmsg()]. 8146** 8147** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 8148** from SQL. 8149*/ 8150int sqlite3_wal_checkpoint_v2( 8151 sqlite3 *db, /* Database handle */ 8152 const char *zDb, /* Name of attached database (or NULL) */ 8153 int eMode, /* SQLITE_CHECKPOINT_* value */ 8154 int *pnLog, /* OUT: Size of WAL log in frames */ 8155 int *pnCkpt /* OUT: Total number of frames checkpointed */ 8156); 8157 8158/* 8159** CAPI3REF: Checkpoint Mode Values 8160** KEYWORDS: {checkpoint mode} 8161** 8162** These constants define all valid values for the "checkpoint mode" passed 8163** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 8164** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 8165** meaning of each of these checkpoint modes. 8166*/ 8167#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 8168#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 8169#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 8170#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 8171 8172/* 8173** CAPI3REF: Virtual Table Interface Configuration 8174** 8175** This function may be called by either the [xConnect] or [xCreate] method 8176** of a [virtual table] implementation to configure 8177** various facets of the virtual table interface. 8178** 8179** If this interface is invoked outside the context of an xConnect or 8180** xCreate virtual table method then the behavior is undefined. 8181** 8182** At present, there is only one option that may be configured using 8183** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 8184** may be added in the future. 8185*/ 8186int sqlite3_vtab_config(sqlite3*, int op, ...); 8187 8188/* 8189** CAPI3REF: Virtual Table Configuration Options 8190** 8191** These macros define the various options to the 8192** [sqlite3_vtab_config()] interface that [virtual table] implementations 8193** can use to customize and optimize their behavior. 8194** 8195** <dl> 8196** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 8197** <dd>Calls of the form 8198** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 8199** where X is an integer. If X is zero, then the [virtual table] whose 8200** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 8201** support constraints. In this configuration (which is the default) if 8202** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 8203** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 8204** specified as part of the users SQL statement, regardless of the actual 8205** ON CONFLICT mode specified. 8206** 8207** If X is non-zero, then the virtual table implementation guarantees 8208** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 8209** any modifications to internal or persistent data structures have been made. 8210** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 8211** is able to roll back a statement or database transaction, and abandon 8212** or continue processing the current SQL statement as appropriate. 8213** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 8214** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 8215** had been ABORT. 8216** 8217** Virtual table implementations that are required to handle OR REPLACE 8218** must do so within the [xUpdate] method. If a call to the 8219** [sqlite3_vtab_on_conflict()] function indicates that the current ON 8220** CONFLICT policy is REPLACE, the virtual table implementation should 8221** silently replace the appropriate rows within the xUpdate callback and 8222** return SQLITE_OK. Or, if this is not possible, it may return 8223** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 8224** constraint handling. 8225** </dl> 8226*/ 8227#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 8228 8229/* 8230** CAPI3REF: Determine The Virtual Table Conflict Policy 8231** 8232** This function may only be called from within a call to the [xUpdate] method 8233** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 8234** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 8235** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 8236** of the SQL statement that triggered the call to the [xUpdate] method of the 8237** [virtual table]. 8238*/ 8239int sqlite3_vtab_on_conflict(sqlite3 *); 8240 8241/* 8242** CAPI3REF: Conflict resolution modes 8243** KEYWORDS: {conflict resolution mode} 8244** 8245** These constants are returned by [sqlite3_vtab_on_conflict()] to 8246** inform a [virtual table] implementation what the [ON CONFLICT] mode 8247** is for the SQL statement being evaluated. 8248** 8249** Note that the [SQLITE_IGNORE] constant is also used as a potential 8250** return value from the [sqlite3_set_authorizer()] callback and that 8251** [SQLITE_ABORT] is also a [result code]. 8252*/ 8253#define SQLITE_ROLLBACK 1 8254/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 8255#define SQLITE_FAIL 3 8256/* #define SQLITE_ABORT 4 // Also an error code */ 8257#define SQLITE_REPLACE 5 8258 8259/* 8260** CAPI3REF: Prepared Statement Scan Status Opcodes 8261** KEYWORDS: {scanstatus options} 8262** 8263** The following constants can be used for the T parameter to the 8264** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 8265** different metric for sqlite3_stmt_scanstatus() to return. 8266** 8267** When the value returned to V is a string, space to hold that string is 8268** managed by the prepared statement S and will be automatically freed when 8269** S is finalized. 8270** 8271** <dl> 8272** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 8273** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 8274** set to the total number of times that the X-th loop has run.</dd> 8275** 8276** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 8277** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 8278** to the total number of rows examined by all iterations of the X-th loop.</dd> 8279** 8280** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 8281** <dd>^The "double" variable pointed to by the T parameter will be set to the 8282** query planner's estimate for the average number of rows output from each 8283** iteration of the X-th loop. If the query planner's estimates was accurate, 8284** then this value will approximate the quotient NVISIT/NLOOP and the 8285** product of this value for all prior loops with the same SELECTID will 8286** be the NLOOP value for the current loop. 8287** 8288** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 8289** <dd>^The "const char *" variable pointed to by the T parameter will be set 8290** to a zero-terminated UTF-8 string containing the name of the index or table 8291** used for the X-th loop. 8292** 8293** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 8294** <dd>^The "const char *" variable pointed to by the T parameter will be set 8295** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 8296** description for the X-th loop. 8297** 8298** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 8299** <dd>^The "int" variable pointed to by the T parameter will be set to the 8300** "select-id" for the X-th loop. The select-id identifies which query or 8301** subquery the loop is part of. The main query has a select-id of zero. 8302** The select-id is the same value as is output in the first column 8303** of an [EXPLAIN QUERY PLAN] query. 8304** </dl> 8305*/ 8306#define SQLITE_SCANSTAT_NLOOP 0 8307#define SQLITE_SCANSTAT_NVISIT 1 8308#define SQLITE_SCANSTAT_EST 2 8309#define SQLITE_SCANSTAT_NAME 3 8310#define SQLITE_SCANSTAT_EXPLAIN 4 8311#define SQLITE_SCANSTAT_SELECTID 5 8312 8313/* 8314** CAPI3REF: Prepared Statement Scan Status 8315** METHOD: sqlite3_stmt 8316** 8317** This interface returns information about the predicted and measured 8318** performance for pStmt. Advanced applications can use this 8319** interface to compare the predicted and the measured performance and 8320** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 8321** 8322** Since this interface is expected to be rarely used, it is only 8323** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 8324** compile-time option. 8325** 8326** The "iScanStatusOp" parameter determines which status information to return. 8327** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 8328** of this interface is undefined. 8329** ^The requested measurement is written into a variable pointed to by 8330** the "pOut" parameter. 8331** Parameter "idx" identifies the specific loop to retrieve statistics for. 8332** Loops are numbered starting from zero. ^If idx is out of range - less than 8333** zero or greater than or equal to the total number of loops used to implement 8334** the statement - a non-zero value is returned and the variable that pOut 8335** points to is unchanged. 8336** 8337** ^Statistics might not be available for all loops in all statements. ^In cases 8338** where there exist loops with no available statistics, this function behaves 8339** as if the loop did not exist - it returns non-zero and leave the variable 8340** that pOut points to unchanged. 8341** 8342** See also: [sqlite3_stmt_scanstatus_reset()] 8343*/ 8344int sqlite3_stmt_scanstatus( 8345 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 8346 int idx, /* Index of loop to report on */ 8347 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 8348 void *pOut /* Result written here */ 8349); 8350 8351/* 8352** CAPI3REF: Zero Scan-Status Counters 8353** METHOD: sqlite3_stmt 8354** 8355** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 8356** 8357** This API is only available if the library is built with pre-processor 8358** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 8359*/ 8360void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 8361 8362/* 8363** CAPI3REF: Flush caches to disk mid-transaction 8364** 8365** ^If a write-transaction is open on [database connection] D when the 8366** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 8367** pages in the pager-cache that are not currently in use are written out 8368** to disk. A dirty page may be in use if a database cursor created by an 8369** active SQL statement is reading from it, or if it is page 1 of a database 8370** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 8371** interface flushes caches for all schemas - "main", "temp", and 8372** any [attached] databases. 8373** 8374** ^If this function needs to obtain extra database locks before dirty pages 8375** can be flushed to disk, it does so. ^If those locks cannot be obtained 8376** immediately and there is a busy-handler callback configured, it is invoked 8377** in the usual manner. ^If the required lock still cannot be obtained, then 8378** the database is skipped and an attempt made to flush any dirty pages 8379** belonging to the next (if any) database. ^If any databases are skipped 8380** because locks cannot be obtained, but no other error occurs, this 8381** function returns SQLITE_BUSY. 8382** 8383** ^If any other error occurs while flushing dirty pages to disk (for 8384** example an IO error or out-of-memory condition), then processing is 8385** abandoned and an SQLite [error code] is returned to the caller immediately. 8386** 8387** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 8388** 8389** ^This function does not set the database handle error code or message 8390** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 8391*/ 8392int sqlite3_db_cacheflush(sqlite3*); 8393 8394/* 8395** CAPI3REF: The pre-update hook. 8396** 8397** ^These interfaces are only available if SQLite is compiled using the 8398** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 8399** 8400** ^The [sqlite3_preupdate_hook()] interface registers a callback function 8401** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 8402** on a database table. 8403** ^At most one preupdate hook may be registered at a time on a single 8404** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 8405** the previous setting. 8406** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 8407** with a NULL pointer as the second parameter. 8408** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 8409** the first parameter to callbacks. 8410** 8411** ^The preupdate hook only fires for changes to real database tables; the 8412** preupdate hook is not invoked for changes to [virtual tables] or to 8413** system tables like sqlite_master or sqlite_stat1. 8414** 8415** ^The second parameter to the preupdate callback is a pointer to 8416** the [database connection] that registered the preupdate hook. 8417** ^The third parameter to the preupdate callback is one of the constants 8418** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 8419** kind of update operation that is about to occur. 8420** ^(The fourth parameter to the preupdate callback is the name of the 8421** database within the database connection that is being modified. This 8422** will be "main" for the main database or "temp" for TEMP tables or 8423** the name given after the AS keyword in the [ATTACH] statement for attached 8424** databases.)^ 8425** ^The fifth parameter to the preupdate callback is the name of the 8426** table that is being modified. 8427** 8428** For an UPDATE or DELETE operation on a [rowid table], the sixth 8429** parameter passed to the preupdate callback is the initial [rowid] of the 8430** row being modified or deleted. For an INSERT operation on a rowid table, 8431** or any operation on a WITHOUT ROWID table, the value of the sixth 8432** parameter is undefined. For an INSERT or UPDATE on a rowid table the 8433** seventh parameter is the final rowid value of the row being inserted 8434** or updated. The value of the seventh parameter passed to the callback 8435** function is not defined for operations on WITHOUT ROWID tables, or for 8436** INSERT operations on rowid tables. 8437** 8438** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 8439** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 8440** provide additional information about a preupdate event. These routines 8441** may only be called from within a preupdate callback. Invoking any of 8442** these routines from outside of a preupdate callback or with a 8443** [database connection] pointer that is different from the one supplied 8444** to the preupdate callback results in undefined and probably undesirable 8445** behavior. 8446** 8447** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 8448** in the row that is being inserted, updated, or deleted. 8449** 8450** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 8451** a [protected sqlite3_value] that contains the value of the Nth column of 8452** the table row before it is updated. The N parameter must be between 0 8453** and one less than the number of columns or the behavior will be 8454** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 8455** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 8456** behavior is undefined. The [sqlite3_value] that P points to 8457** will be destroyed when the preupdate callback returns. 8458** 8459** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 8460** a [protected sqlite3_value] that contains the value of the Nth column of 8461** the table row after it is updated. The N parameter must be between 0 8462** and one less than the number of columns or the behavior will be 8463** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 8464** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 8465** behavior is undefined. The [sqlite3_value] that P points to 8466** will be destroyed when the preupdate callback returns. 8467** 8468** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 8469** callback was invoked as a result of a direct insert, update, or delete 8470** operation; or 1 for inserts, updates, or deletes invoked by top-level 8471** triggers; or 2 for changes resulting from triggers called by top-level 8472** triggers; and so forth. 8473** 8474** See also: [sqlite3_update_hook()] 8475*/ 8476#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 8477void *sqlite3_preupdate_hook( 8478 sqlite3 *db, 8479 void(*xPreUpdate)( 8480 void *pCtx, /* Copy of third arg to preupdate_hook() */ 8481 sqlite3 *db, /* Database handle */ 8482 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 8483 char const *zDb, /* Database name */ 8484 char const *zName, /* Table name */ 8485 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 8486 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 8487 ), 8488 void* 8489); 8490int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 8491int sqlite3_preupdate_count(sqlite3 *); 8492int sqlite3_preupdate_depth(sqlite3 *); 8493int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 8494#endif 8495 8496/* 8497** CAPI3REF: Low-level system error code 8498** 8499** ^Attempt to return the underlying operating system error code or error 8500** number that caused the most recent I/O error or failure to open a file. 8501** The return value is OS-dependent. For example, on unix systems, after 8502** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 8503** called to get back the underlying "errno" that caused the problem, such 8504** as ENOSPC, EAUTH, EISDIR, and so forth. 8505*/ 8506int sqlite3_system_errno(sqlite3*); 8507 8508/* 8509** CAPI3REF: Database Snapshot 8510** KEYWORDS: {snapshot} {sqlite3_snapshot} 8511** EXPERIMENTAL 8512** 8513** An instance of the snapshot object records the state of a [WAL mode] 8514** database for some specific point in history. 8515** 8516** In [WAL mode], multiple [database connections] that are open on the 8517** same database file can each be reading a different historical version 8518** of the database file. When a [database connection] begins a read 8519** transaction, that connection sees an unchanging copy of the database 8520** as it existed for the point in time when the transaction first started. 8521** Subsequent changes to the database from other connections are not seen 8522** by the reader until a new read transaction is started. 8523** 8524** The sqlite3_snapshot object records state information about an historical 8525** version of the database file so that it is possible to later open a new read 8526** transaction that sees that historical version of the database rather than 8527** the most recent version. 8528** 8529** The constructor for this object is [sqlite3_snapshot_get()]. The 8530** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer 8531** to an historical snapshot (if possible). The destructor for 8532** sqlite3_snapshot objects is [sqlite3_snapshot_free()]. 8533*/ 8534typedef struct sqlite3_snapshot { 8535 unsigned char hidden[48]; 8536} sqlite3_snapshot; 8537 8538/* 8539** CAPI3REF: Record A Database Snapshot 8540** EXPERIMENTAL 8541** 8542** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 8543** new [sqlite3_snapshot] object that records the current state of 8544** schema S in database connection D. ^On success, the 8545** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 8546** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 8547** If there is not already a read-transaction open on schema S when 8548** this function is called, one is opened automatically. 8549** 8550** The following must be true for this function to succeed. If any of 8551** the following statements are false when sqlite3_snapshot_get() is 8552** called, SQLITE_ERROR is returned. The final value of *P is undefined 8553** in this case. 8554** 8555** <ul> 8556** <li> The database handle must be in [autocommit mode]. 8557** 8558** <li> Schema S of [database connection] D must be a [WAL mode] database. 8559** 8560** <li> There must not be a write transaction open on schema S of database 8561** connection D. 8562** 8563** <li> One or more transactions must have been written to the current wal 8564** file since it was created on disk (by any connection). This means 8565** that a snapshot cannot be taken on a wal mode database with no wal 8566** file immediately after it is first opened. At least one transaction 8567** must be written to it first. 8568** </ul> 8569** 8570** This function may also return SQLITE_NOMEM. If it is called with the 8571** database handle in autocommit mode but fails for some other reason, 8572** whether or not a read transaction is opened on schema S is undefined. 8573** 8574** The [sqlite3_snapshot] object returned from a successful call to 8575** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 8576** to avoid a memory leak. 8577** 8578** The [sqlite3_snapshot_get()] interface is only available when the 8579** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8580*/ 8581SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 8582 sqlite3 *db, 8583 const char *zSchema, 8584 sqlite3_snapshot **ppSnapshot 8585); 8586 8587/* 8588** CAPI3REF: Start a read transaction on an historical snapshot 8589** EXPERIMENTAL 8590** 8591** ^The [sqlite3_snapshot_open(D,S,P)] interface starts a 8592** read transaction for schema S of 8593** [database connection] D such that the read transaction 8594** refers to historical [snapshot] P, rather than the most 8595** recent change to the database. 8596** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success 8597** or an appropriate [error code] if it fails. 8598** 8599** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be 8600** the first operation following the [BEGIN] that takes the schema S 8601** out of [autocommit mode]. 8602** ^In other words, schema S must not currently be in 8603** a transaction for [sqlite3_snapshot_open(D,S,P)] to work, but the 8604** database connection D must be out of [autocommit mode]. 8605** ^A [snapshot] will fail to open if it has been overwritten by a 8606** [checkpoint]. 8607** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 8608** database connection D does not know that the database file for 8609** schema S is in [WAL mode]. A database connection might not know 8610** that the database file is in [WAL mode] if there has been no prior 8611** I/O on that database connection, or if the database entered [WAL mode] 8612** after the most recent I/O on the database connection.)^ 8613** (Hint: Run "[PRAGMA application_id]" against a newly opened 8614** database connection in order to make it ready to use snapshots.) 8615** 8616** The [sqlite3_snapshot_open()] interface is only available when the 8617** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8618*/ 8619SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 8620 sqlite3 *db, 8621 const char *zSchema, 8622 sqlite3_snapshot *pSnapshot 8623); 8624 8625/* 8626** CAPI3REF: Destroy a snapshot 8627** EXPERIMENTAL 8628** 8629** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 8630** The application must eventually free every [sqlite3_snapshot] object 8631** using this routine to avoid a memory leak. 8632** 8633** The [sqlite3_snapshot_free()] interface is only available when the 8634** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8635*/ 8636SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 8637 8638/* 8639** CAPI3REF: Compare the ages of two snapshot handles. 8640** EXPERIMENTAL 8641** 8642** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 8643** of two valid snapshot handles. 8644** 8645** If the two snapshot handles are not associated with the same database 8646** file, the result of the comparison is undefined. 8647** 8648** Additionally, the result of the comparison is only valid if both of the 8649** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 8650** last time the wal file was deleted. The wal file is deleted when the 8651** database is changed back to rollback mode or when the number of database 8652** clients drops to zero. If either snapshot handle was obtained before the 8653** wal file was last deleted, the value returned by this function 8654** is undefined. 8655** 8656** Otherwise, this API returns a negative value if P1 refers to an older 8657** snapshot than P2, zero if the two handles refer to the same database 8658** snapshot, and a positive value if P1 is a newer snapshot than P2. 8659*/ 8660SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 8661 sqlite3_snapshot *p1, 8662 sqlite3_snapshot *p2 8663); 8664 8665/* 8666** CAPI3REF: Recover snapshots from a wal file 8667** EXPERIMENTAL 8668** 8669** If all connections disconnect from a database file but do not perform 8670** a checkpoint, the existing wal file is opened along with the database 8671** file the next time the database is opened. At this point it is only 8672** possible to successfully call sqlite3_snapshot_open() to open the most 8673** recent snapshot of the database (the one at the head of the wal file), 8674** even though the wal file may contain other valid snapshots for which 8675** clients have sqlite3_snapshot handles. 8676** 8677** This function attempts to scan the wal file associated with database zDb 8678** of database handle db and make all valid snapshots available to 8679** sqlite3_snapshot_open(). It is an error if there is already a read 8680** transaction open on the database, or if the database is not a wal mode 8681** database. 8682** 8683** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 8684*/ 8685SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 8686 8687/* 8688** Undo the hack that converts floating point types to integer for 8689** builds on processors without floating point support. 8690*/ 8691#ifdef SQLITE_OMIT_FLOATING_POINT 8692# undef double 8693#endif 8694 8695#ifdef __cplusplus 8696} /* End of the 'extern "C"' block */ 8697#endif 8698#endif /* SQLITE3_H */ 8699