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. If the source code has 119** been edited in any way since it was last checked in, then the last 120** four hexadecimal digits of the hash may be modified. 121** 122** See also: [sqlite3_libversion()], 123** [sqlite3_libversion_number()], [sqlite3_sourceid()], 124** [sqlite_version()] and [sqlite_source_id()]. 125*/ 126#define SQLITE_VERSION "--VERS--" 127#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 128#define SQLITE_SOURCE_ID "--SOURCE-ID--" 129 130/* 131** CAPI3REF: Run-Time Library Version Numbers 132** KEYWORDS: sqlite3_version sqlite3_sourceid 133** 134** These interfaces provide the same information as the [SQLITE_VERSION], 135** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 136** but are associated with the library instead of the header file. ^(Cautious 137** programmers might include assert() statements in their application to 138** verify that values returned by these interfaces match the macros in 139** the header, and thus ensure that the application is 140** compiled with matching library and header files. 141** 142** <blockquote><pre> 143** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 144** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 ); 145** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 146** </pre></blockquote>)^ 147** 148** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 149** macro. ^The sqlite3_libversion() function returns a pointer to the 150** to the sqlite3_version[] string constant. The sqlite3_libversion() 151** function is provided for use in DLLs since DLL users usually do not have 152** direct access to string constants within the DLL. ^The 153** sqlite3_libversion_number() function returns an integer equal to 154** [SQLITE_VERSION_NUMBER]. ^(The sqlite3_sourceid() function returns 155** a pointer to a string constant whose value is the same as the 156** [SQLITE_SOURCE_ID] C preprocessor macro. Except if SQLite is built 157** using an edited copy of [the amalgamation], then the last four characters 158** of the hash might be different from [SQLITE_SOURCE_ID].)^ 159** 160** See also: [sqlite_version()] and [sqlite_source_id()]. 161*/ 162SQLITE_EXTERN const char sqlite3_version[]; 163const char *sqlite3_libversion(void); 164const char *sqlite3_sourceid(void); 165int sqlite3_libversion_number(void); 166 167/* 168** CAPI3REF: Run-Time Library Compilation Options Diagnostics 169** 170** ^The sqlite3_compileoption_used() function returns 0 or 1 171** indicating whether the specified option was defined at 172** compile time. ^The SQLITE_ prefix may be omitted from the 173** option name passed to sqlite3_compileoption_used(). 174** 175** ^The sqlite3_compileoption_get() function allows iterating 176** over the list of options that were defined at compile time by 177** returning the N-th compile time option string. ^If N is out of range, 178** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 179** prefix is omitted from any strings returned by 180** sqlite3_compileoption_get(). 181** 182** ^Support for the diagnostic functions sqlite3_compileoption_used() 183** and sqlite3_compileoption_get() may be omitted by specifying the 184** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 185** 186** See also: SQL functions [sqlite_compileoption_used()] and 187** [sqlite_compileoption_get()] and the [compile_options pragma]. 188*/ 189#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 190int sqlite3_compileoption_used(const char *zOptName); 191const char *sqlite3_compileoption_get(int N); 192#endif 193 194/* 195** CAPI3REF: Test To See If The Library Is Threadsafe 196** 197** ^The sqlite3_threadsafe() function returns zero if and only if 198** SQLite was compiled with mutexing code omitted due to the 199** [SQLITE_THREADSAFE] compile-time option being set to 0. 200** 201** SQLite can be compiled with or without mutexes. When 202** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 203** are enabled and SQLite is threadsafe. When the 204** [SQLITE_THREADSAFE] macro is 0, 205** the mutexes are omitted. Without the mutexes, it is not safe 206** to use SQLite concurrently from more than one thread. 207** 208** Enabling mutexes incurs a measurable performance penalty. 209** So if speed is of utmost importance, it makes sense to disable 210** the mutexes. But for maximum safety, mutexes should be enabled. 211** ^The default behavior is for mutexes to be enabled. 212** 213** This interface can be used by an application to make sure that the 214** version of SQLite that it is linking against was compiled with 215** the desired setting of the [SQLITE_THREADSAFE] macro. 216** 217** This interface only reports on the compile-time mutex setting 218** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 219** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 220** can be fully or partially disabled using a call to [sqlite3_config()] 221** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 222** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the 223** sqlite3_threadsafe() function shows only the compile-time setting of 224** thread safety, not any run-time changes to that setting made by 225** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 226** is unchanged by calls to sqlite3_config().)^ 227** 228** See the [threading mode] documentation for additional information. 229*/ 230int sqlite3_threadsafe(void); 231 232/* 233** CAPI3REF: Database Connection Handle 234** KEYWORDS: {database connection} {database connections} 235** 236** Each open SQLite database is represented by a pointer to an instance of 237** the opaque structure named "sqlite3". It is useful to think of an sqlite3 238** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 239** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 240** and [sqlite3_close_v2()] are its destructors. There are many other 241** interfaces (such as 242** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 243** [sqlite3_busy_timeout()] to name but three) that are methods on an 244** sqlite3 object. 245*/ 246typedef struct sqlite3 sqlite3; 247 248/* 249** CAPI3REF: 64-Bit Integer Types 250** KEYWORDS: sqlite_int64 sqlite_uint64 251** 252** Because there is no cross-platform way to specify 64-bit integer types 253** SQLite includes typedefs for 64-bit signed and unsigned integers. 254** 255** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 256** The sqlite_int64 and sqlite_uint64 types are supported for backwards 257** compatibility only. 258** 259** ^The sqlite3_int64 and sqlite_int64 types can store integer values 260** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 261** sqlite3_uint64 and sqlite_uint64 types can store integer values 262** between 0 and +18446744073709551615 inclusive. 263*/ 264#ifdef SQLITE_INT64_TYPE 265 typedef SQLITE_INT64_TYPE sqlite_int64; 266# ifdef SQLITE_UINT64_TYPE 267 typedef SQLITE_UINT64_TYPE sqlite_uint64; 268# else 269 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 270# endif 271#elif defined(_MSC_VER) || defined(__BORLANDC__) 272 typedef __int64 sqlite_int64; 273 typedef unsigned __int64 sqlite_uint64; 274#else 275 typedef long long int sqlite_int64; 276 typedef unsigned long long int sqlite_uint64; 277#endif 278typedef sqlite_int64 sqlite3_int64; 279typedef sqlite_uint64 sqlite3_uint64; 280 281/* 282** If compiling for a processor that lacks floating point support, 283** substitute integer for floating-point. 284*/ 285#ifdef SQLITE_OMIT_FLOATING_POINT 286# define double sqlite3_int64 287#endif 288 289/* 290** CAPI3REF: Closing A Database Connection 291** DESTRUCTOR: sqlite3 292** 293** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 294** for the [sqlite3] object. 295** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 296** the [sqlite3] object is successfully destroyed and all associated 297** resources are deallocated. 298** 299** ^If the database connection is associated with unfinalized prepared 300** statements or unfinished sqlite3_backup objects then sqlite3_close() 301** will leave the database connection open and return [SQLITE_BUSY]. 302** ^If sqlite3_close_v2() is called with unfinalized prepared statements 303** and/or unfinished sqlite3_backups, then the database connection becomes 304** an unusable "zombie" which will automatically be deallocated when the 305** last prepared statement is finalized or the last sqlite3_backup is 306** finished. The sqlite3_close_v2() interface is intended for use with 307** host languages that are garbage collected, and where the order in which 308** destructors are called is arbitrary. 309** 310** Applications should [sqlite3_finalize | finalize] all [prepared statements], 311** [sqlite3_blob_close | close] all [BLOB handles], and 312** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 313** with the [sqlite3] object prior to attempting to close the object. ^If 314** sqlite3_close_v2() is called on a [database connection] that still has 315** outstanding [prepared statements], [BLOB handles], and/or 316** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation 317** of resources is deferred until all [prepared statements], [BLOB handles], 318** and [sqlite3_backup] objects are also destroyed. 319** 320** ^If an [sqlite3] object is destroyed while a transaction is open, 321** the transaction is automatically rolled back. 322** 323** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 324** must be either a NULL 325** pointer or an [sqlite3] object pointer obtained 326** from [sqlite3_open()], [sqlite3_open16()], or 327** [sqlite3_open_v2()], and not previously closed. 328** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 329** argument is a harmless no-op. 330*/ 331int sqlite3_close(sqlite3*); 332int sqlite3_close_v2(sqlite3*); 333 334/* 335** The type for a callback function. 336** This is legacy and deprecated. It is included for historical 337** compatibility and is not documented. 338*/ 339typedef int (*sqlite3_callback)(void*,int,char**, char**); 340 341/* 342** CAPI3REF: One-Step Query Execution Interface 343** METHOD: sqlite3 344** 345** The sqlite3_exec() interface is a convenience wrapper around 346** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 347** that allows an application to run multiple statements of SQL 348** without having to use a lot of C code. 349** 350** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 351** semicolon-separate SQL statements passed into its 2nd argument, 352** in the context of the [database connection] passed in as its 1st 353** argument. ^If the callback function of the 3rd argument to 354** sqlite3_exec() is not NULL, then it is invoked for each result row 355** coming out of the evaluated SQL statements. ^The 4th argument to 356** sqlite3_exec() is relayed through to the 1st argument of each 357** callback invocation. ^If the callback pointer to sqlite3_exec() 358** is NULL, then no callback is ever invoked and result rows are 359** ignored. 360** 361** ^If an error occurs while evaluating the SQL statements passed into 362** sqlite3_exec(), then execution of the current statement stops and 363** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 364** is not NULL then any error message is written into memory obtained 365** from [sqlite3_malloc()] and passed back through the 5th parameter. 366** To avoid memory leaks, the application should invoke [sqlite3_free()] 367** on error message strings returned through the 5th parameter of 368** sqlite3_exec() after the error message string is no longer needed. 369** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 370** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 371** NULL before returning. 372** 373** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 374** routine returns SQLITE_ABORT without invoking the callback again and 375** without running any subsequent SQL statements. 376** 377** ^The 2nd argument to the sqlite3_exec() callback function is the 378** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 379** callback is an array of pointers to strings obtained as if from 380** [sqlite3_column_text()], one for each column. ^If an element of a 381** result row is NULL then the corresponding string pointer for the 382** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 383** sqlite3_exec() callback is an array of pointers to strings where each 384** entry represents the name of corresponding result column as obtained 385** from [sqlite3_column_name()]. 386** 387** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 388** to an empty string, or a pointer that contains only whitespace and/or 389** SQL comments, then no SQL statements are evaluated and the database 390** is not changed. 391** 392** Restrictions: 393** 394** <ul> 395** <li> The application must ensure that the 1st parameter to sqlite3_exec() 396** is a valid and open [database connection]. 397** <li> The application must not close the [database connection] specified by 398** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 399** <li> The application must not modify the SQL statement text passed into 400** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 401** </ul> 402*/ 403int sqlite3_exec( 404 sqlite3*, /* An open database */ 405 const char *sql, /* SQL to be evaluated */ 406 int (*callback)(void*,int,char**,char**), /* Callback function */ 407 void *, /* 1st argument to callback */ 408 char **errmsg /* Error msg written here */ 409); 410 411/* 412** CAPI3REF: Result Codes 413** KEYWORDS: {result code definitions} 414** 415** Many SQLite functions return an integer result code from the set shown 416** here in order to indicate success or failure. 417** 418** New error codes may be added in future versions of SQLite. 419** 420** See also: [extended result code definitions] 421*/ 422#define SQLITE_OK 0 /* Successful result */ 423/* beginning-of-error-codes */ 424#define SQLITE_ERROR 1 /* Generic error */ 425#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 426#define SQLITE_PERM 3 /* Access permission denied */ 427#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 428#define SQLITE_BUSY 5 /* The database file is locked */ 429#define SQLITE_LOCKED 6 /* A table in the database is locked */ 430#define SQLITE_NOMEM 7 /* A malloc() failed */ 431#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 432#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 433#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 434#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 435#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 436#define SQLITE_FULL 13 /* Insertion failed because database is full */ 437#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 438#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 439#define SQLITE_EMPTY 16 /* Internal use only */ 440#define SQLITE_SCHEMA 17 /* The database schema changed */ 441#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 442#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 443#define SQLITE_MISMATCH 20 /* Data type mismatch */ 444#define SQLITE_MISUSE 21 /* Library used incorrectly */ 445#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 446#define SQLITE_AUTH 23 /* Authorization denied */ 447#define SQLITE_FORMAT 24 /* Not used */ 448#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 449#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 450#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 451#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 452#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 453#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 454/* end-of-error-codes */ 455 456/* 457** CAPI3REF: Extended Result Codes 458** KEYWORDS: {extended result code definitions} 459** 460** In its default configuration, SQLite API routines return one of 30 integer 461** [result codes]. However, experience has shown that many of 462** these result codes are too coarse-grained. They do not provide as 463** much information about problems as programmers might like. In an effort to 464** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8] 465** and later) include 466** support for additional result codes that provide more detailed information 467** about errors. These [extended result codes] are enabled or disabled 468** on a per database connection basis using the 469** [sqlite3_extended_result_codes()] API. Or, the extended code for 470** the most recent error can be obtained using 471** [sqlite3_extended_errcode()]. 472*/ 473#define SQLITE_ERROR_MISSING_COLLSEQ (SQLITE_ERROR | (1<<8)) 474#define SQLITE_ERROR_RETRY (SQLITE_ERROR | (2<<8)) 475#define SQLITE_ERROR_SNAPSHOT (SQLITE_ERROR | (3<<8)) 476#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 477#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 478#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 479#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 480#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 481#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 482#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 483#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 484#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 485#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 486#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 487#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 488#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 489#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 490#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 491#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 492#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 493#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 494#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 495#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 496#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 497#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 498#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 499#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 500#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 501#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 502#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8)) 503#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8)) 504#define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8)) 505#define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8)) 506#define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8)) 507#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 508#define SQLITE_LOCKED_VTAB (SQLITE_LOCKED | (2<<8)) 509#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 510#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 511#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 512#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 513#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 514#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 515#define SQLITE_CANTOPEN_DIRTYWAL (SQLITE_CANTOPEN | (5<<8)) /* Not Used */ 516#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 517#define SQLITE_CORRUPT_SEQUENCE (SQLITE_CORRUPT | (2<<8)) 518#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 519#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 520#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 521#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 522#define SQLITE_READONLY_CANTINIT (SQLITE_READONLY | (5<<8)) 523#define SQLITE_READONLY_DIRECTORY (SQLITE_READONLY | (6<<8)) 524#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 525#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 526#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 527#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 528#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 529#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 530#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 531#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 532#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 533#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 534#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 535#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 536#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 537#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 538#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 539#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8)) 540 541/* 542** CAPI3REF: Flags For File Open Operations 543** 544** These bit values are intended for use in the 545** 3rd parameter to the [sqlite3_open_v2()] interface and 546** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 547*/ 548#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 549#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 550#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 551#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 552#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 553#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 554#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 555#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 556#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 557#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 558#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 559#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 560#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 561#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 562#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 563#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 564#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 565#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 566#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 567#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 568 569/* Reserved: 0x00F00000 */ 570 571/* 572** CAPI3REF: Device Characteristics 573** 574** The xDeviceCharacteristics method of the [sqlite3_io_methods] 575** object returns an integer which is a vector of these 576** bit values expressing I/O characteristics of the mass storage 577** device that holds the file that the [sqlite3_io_methods] 578** refers to. 579** 580** The SQLITE_IOCAP_ATOMIC property means that all writes of 581** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 582** mean that writes of blocks that are nnn bytes in size and 583** are aligned to an address which is an integer multiple of 584** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 585** that when data is appended to a file, the data is appended 586** first then the size of the file is extended, never the other 587** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 588** information is written to disk in the same order as calls 589** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 590** after reboot following a crash or power loss, the only bytes in a 591** file that were written at the application level might have changed 592** and that adjacent bytes, even bytes within the same sector are 593** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 594** flag indicates that a file cannot be deleted when open. The 595** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 596** read-only media and cannot be changed even by processes with 597** elevated privileges. 598** 599** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying 600** filesystem supports doing multiple write operations atomically when those 601** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and 602** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. 603*/ 604#define SQLITE_IOCAP_ATOMIC 0x00000001 605#define SQLITE_IOCAP_ATOMIC512 0x00000002 606#define SQLITE_IOCAP_ATOMIC1K 0x00000004 607#define SQLITE_IOCAP_ATOMIC2K 0x00000008 608#define SQLITE_IOCAP_ATOMIC4K 0x00000010 609#define SQLITE_IOCAP_ATOMIC8K 0x00000020 610#define SQLITE_IOCAP_ATOMIC16K 0x00000040 611#define SQLITE_IOCAP_ATOMIC32K 0x00000080 612#define SQLITE_IOCAP_ATOMIC64K 0x00000100 613#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 614#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 615#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 616#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 617#define SQLITE_IOCAP_IMMUTABLE 0x00002000 618#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000 619 620/* 621** CAPI3REF: File Locking Levels 622** 623** SQLite uses one of these integer values as the second 624** argument to calls it makes to the xLock() and xUnlock() methods 625** of an [sqlite3_io_methods] object. 626*/ 627#define SQLITE_LOCK_NONE 0 628#define SQLITE_LOCK_SHARED 1 629#define SQLITE_LOCK_RESERVED 2 630#define SQLITE_LOCK_PENDING 3 631#define SQLITE_LOCK_EXCLUSIVE 4 632 633/* 634** CAPI3REF: Synchronization Type Flags 635** 636** When SQLite invokes the xSync() method of an 637** [sqlite3_io_methods] object it uses a combination of 638** these integer values as the second argument. 639** 640** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 641** sync operation only needs to flush data to mass storage. Inode 642** information need not be flushed. If the lower four bits of the flag 643** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 644** If the lower four bits equal SQLITE_SYNC_FULL, that means 645** to use Mac OS X style fullsync instead of fsync(). 646** 647** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 648** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 649** settings. The [synchronous pragma] determines when calls to the 650** xSync VFS method occur and applies uniformly across all platforms. 651** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 652** energetic or rigorous or forceful the sync operations are and 653** only make a difference on Mac OSX for the default SQLite code. 654** (Third-party VFS implementations might also make the distinction 655** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 656** operating systems natively supported by SQLite, only Mac OSX 657** cares about the difference.) 658*/ 659#define SQLITE_SYNC_NORMAL 0x00002 660#define SQLITE_SYNC_FULL 0x00003 661#define SQLITE_SYNC_DATAONLY 0x00010 662 663/* 664** CAPI3REF: OS Interface Open File Handle 665** 666** An [sqlite3_file] object represents an open file in the 667** [sqlite3_vfs | OS interface layer]. Individual OS interface 668** implementations will 669** want to subclass this object by appending additional fields 670** for their own use. The pMethods entry is a pointer to an 671** [sqlite3_io_methods] object that defines methods for performing 672** I/O operations on the open file. 673*/ 674typedef struct sqlite3_file sqlite3_file; 675struct sqlite3_file { 676 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 677}; 678 679/* 680** CAPI3REF: OS Interface File Virtual Methods Object 681** 682** Every file opened by the [sqlite3_vfs.xOpen] method populates an 683** [sqlite3_file] object (or, more commonly, a subclass of the 684** [sqlite3_file] object) with a pointer to an instance of this object. 685** This object defines the methods used to perform various operations 686** against the open file represented by the [sqlite3_file] object. 687** 688** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 689** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 690** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 691** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 692** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 693** to NULL. 694** 695** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 696** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 697** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 698** flag may be ORed in to indicate that only the data of the file 699** and not its inode needs to be synced. 700** 701** The integer values to xLock() and xUnlock() are one of 702** <ul> 703** <li> [SQLITE_LOCK_NONE], 704** <li> [SQLITE_LOCK_SHARED], 705** <li> [SQLITE_LOCK_RESERVED], 706** <li> [SQLITE_LOCK_PENDING], or 707** <li> [SQLITE_LOCK_EXCLUSIVE]. 708** </ul> 709** xLock() increases the lock. xUnlock() decreases the lock. 710** The xCheckReservedLock() method checks whether any database connection, 711** either in this process or in some other process, is holding a RESERVED, 712** PENDING, or EXCLUSIVE lock on the file. It returns true 713** if such a lock exists and false otherwise. 714** 715** The xFileControl() method is a generic interface that allows custom 716** VFS implementations to directly control an open file using the 717** [sqlite3_file_control()] interface. The second "op" argument is an 718** integer opcode. The third argument is a generic pointer intended to 719** point to a structure that may contain arguments or space in which to 720** write return values. Potential uses for xFileControl() might be 721** functions to enable blocking locks with timeouts, to change the 722** locking strategy (for example to use dot-file locks), to inquire 723** about the status of a lock, or to break stale locks. The SQLite 724** core reserves all opcodes less than 100 for its own use. 725** A [file control opcodes | list of opcodes] less than 100 is available. 726** Applications that define a custom xFileControl method should use opcodes 727** greater than 100 to avoid conflicts. VFS implementations should 728** return [SQLITE_NOTFOUND] for file control opcodes that they do not 729** recognize. 730** 731** The xSectorSize() method returns the sector size of the 732** device that underlies the file. The sector size is the 733** minimum write that can be performed without disturbing 734** other bytes in the file. The xDeviceCharacteristics() 735** method returns a bit vector describing behaviors of the 736** underlying device: 737** 738** <ul> 739** <li> [SQLITE_IOCAP_ATOMIC] 740** <li> [SQLITE_IOCAP_ATOMIC512] 741** <li> [SQLITE_IOCAP_ATOMIC1K] 742** <li> [SQLITE_IOCAP_ATOMIC2K] 743** <li> [SQLITE_IOCAP_ATOMIC4K] 744** <li> [SQLITE_IOCAP_ATOMIC8K] 745** <li> [SQLITE_IOCAP_ATOMIC16K] 746** <li> [SQLITE_IOCAP_ATOMIC32K] 747** <li> [SQLITE_IOCAP_ATOMIC64K] 748** <li> [SQLITE_IOCAP_SAFE_APPEND] 749** <li> [SQLITE_IOCAP_SEQUENTIAL] 750** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN] 751** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE] 752** <li> [SQLITE_IOCAP_IMMUTABLE] 753** <li> [SQLITE_IOCAP_BATCH_ATOMIC] 754** </ul> 755** 756** The SQLITE_IOCAP_ATOMIC property means that all writes of 757** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 758** mean that writes of blocks that are nnn bytes in size and 759** are aligned to an address which is an integer multiple of 760** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 761** that when data is appended to a file, the data is appended 762** first then the size of the file is extended, never the other 763** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 764** information is written to disk in the same order as calls 765** to xWrite(). 766** 767** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 768** in the unread portions of the buffer with zeros. A VFS that 769** fails to zero-fill short reads might seem to work. However, 770** failure to zero-fill short reads will eventually lead to 771** database corruption. 772*/ 773typedef struct sqlite3_io_methods sqlite3_io_methods; 774struct sqlite3_io_methods { 775 int iVersion; 776 int (*xClose)(sqlite3_file*); 777 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 778 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 779 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 780 int (*xSync)(sqlite3_file*, int flags); 781 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 782 int (*xLock)(sqlite3_file*, int); 783 int (*xUnlock)(sqlite3_file*, int); 784 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 785 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 786 int (*xSectorSize)(sqlite3_file*); 787 int (*xDeviceCharacteristics)(sqlite3_file*); 788 /* Methods above are valid for version 1 */ 789 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 790 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 791 void (*xShmBarrier)(sqlite3_file*); 792 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 793 /* Methods above are valid for version 2 */ 794 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 795 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 796 /* Methods above are valid for version 3 */ 797 /* Additional methods may be added in future releases */ 798}; 799 800/* 801** CAPI3REF: Standard File Control Opcodes 802** KEYWORDS: {file control opcodes} {file control opcode} 803** 804** These integer constants are opcodes for the xFileControl method 805** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 806** interface. 807** 808** <ul> 809** <li>[[SQLITE_FCNTL_LOCKSTATE]] 810** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 811** opcode causes the xFileControl method to write the current state of 812** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 813** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 814** into an integer that the pArg argument points to. This capability 815** is used during testing and is only available when the SQLITE_TEST 816** compile-time option is used. 817** 818** <li>[[SQLITE_FCNTL_SIZE_HINT]] 819** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 820** layer a hint of how large the database file will grow to be during the 821** current transaction. This hint is not guaranteed to be accurate but it 822** is often close. The underlying VFS might choose to preallocate database 823** file space based on this hint in order to help writes to the database 824** file run faster. 825** 826** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 827** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 828** extends and truncates the database file in chunks of a size specified 829** by the user. The fourth argument to [sqlite3_file_control()] should 830** point to an integer (type int) containing the new chunk-size to use 831** for the nominated database. Allocating database file space in large 832** chunks (say 1MB at a time), may reduce file-system fragmentation and 833** improve performance on some systems. 834** 835** <li>[[SQLITE_FCNTL_FILE_POINTER]] 836** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 837** to the [sqlite3_file] object associated with a particular database 838** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER]. 839** 840** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]] 841** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer 842** to the [sqlite3_file] object associated with the journal file (either 843** the [rollback journal] or the [write-ahead log]) for a particular database 844** connection. See also [SQLITE_FCNTL_FILE_POINTER]. 845** 846** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 847** No longer in use. 848** 849** <li>[[SQLITE_FCNTL_SYNC]] 850** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 851** sent to the VFS immediately before the xSync method is invoked on a 852** database file descriptor. Or, if the xSync method is not invoked 853** because the user has configured SQLite with 854** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 855** of the xSync method. In most cases, the pointer argument passed with 856** this file-control is NULL. However, if the database file is being synced 857** as part of a multi-database commit, the argument points to a nul-terminated 858** string containing the transactions master-journal file name. VFSes that 859** do not need this signal should silently ignore this opcode. Applications 860** should not call [sqlite3_file_control()] with this opcode as doing so may 861** disrupt the operation of the specialized VFSes that do require it. 862** 863** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 864** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 865** and sent to the VFS after a transaction has been committed immediately 866** but before the database is unlocked. VFSes that do not need this signal 867** should silently ignore this opcode. Applications should not call 868** [sqlite3_file_control()] with this opcode as doing so may disrupt the 869** operation of the specialized VFSes that do require it. 870** 871** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 872** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 873** retry counts and intervals for certain disk I/O operations for the 874** windows [VFS] in order to provide robustness in the presence of 875** anti-virus programs. By default, the windows VFS will retry file read, 876** file write, and file delete operations up to 10 times, with a delay 877** of 25 milliseconds before the first retry and with the delay increasing 878** by an additional 25 milliseconds with each subsequent retry. This 879** opcode allows these two values (10 retries and 25 milliseconds of delay) 880** to be adjusted. The values are changed for all database connections 881** within the same process. The argument is a pointer to an array of two 882** integers where the first integer is the new retry count and the second 883** integer is the delay. If either integer is negative, then the setting 884** is not changed but instead the prior value of that setting is written 885** into the array entry, allowing the current retry settings to be 886** interrogated. The zDbName parameter is ignored. 887** 888** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 889** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 890** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 891** write ahead log ([WAL file]) and shared memory 892** files used for transaction control 893** are automatically deleted when the latest connection to the database 894** closes. Setting persistent WAL mode causes those files to persist after 895** close. Persisting the files is useful when other processes that do not 896** have write permission on the directory containing the database file want 897** to read the database file, as the WAL and shared memory files must exist 898** in order for the database to be readable. The fourth parameter to 899** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 900** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 901** WAL mode. If the integer is -1, then it is overwritten with the current 902** WAL persistence setting. 903** 904** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 905** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 906** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 907** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 908** xDeviceCharacteristics methods. The fourth parameter to 909** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 910** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 911** mode. If the integer is -1, then it is overwritten with the current 912** zero-damage mode setting. 913** 914** <li>[[SQLITE_FCNTL_OVERWRITE]] 915** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 916** a write transaction to indicate that, unless it is rolled back for some 917** reason, the entire database file will be overwritten by the current 918** transaction. This is used by VACUUM operations. 919** 920** <li>[[SQLITE_FCNTL_VFSNAME]] 921** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 922** all [VFSes] in the VFS stack. The names are of all VFS shims and the 923** final bottom-level VFS are written into memory obtained from 924** [sqlite3_malloc()] and the result is stored in the char* variable 925** that the fourth parameter of [sqlite3_file_control()] points to. 926** The caller is responsible for freeing the memory when done. As with 927** all file-control actions, there is no guarantee that this will actually 928** do anything. Callers should initialize the char* variable to a NULL 929** pointer in case this file-control is not implemented. This file-control 930** is intended for diagnostic use only. 931** 932** <li>[[SQLITE_FCNTL_VFS_POINTER]] 933** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 934** [VFSes] currently in use. ^(The argument X in 935** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 936** of type "[sqlite3_vfs] **". This opcodes will set *X 937** to a pointer to the top-level VFS.)^ 938** ^When there are multiple VFS shims in the stack, this opcode finds the 939** upper-most shim only. 940** 941** <li>[[SQLITE_FCNTL_PRAGMA]] 942** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 943** file control is sent to the open [sqlite3_file] object corresponding 944** to the database file to which the pragma statement refers. ^The argument 945** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 946** pointers to strings (char**) in which the second element of the array 947** is the name of the pragma and the third element is the argument to the 948** pragma or NULL if the pragma has no argument. ^The handler for an 949** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 950** of the char** argument point to a string obtained from [sqlite3_mprintf()] 951** or the equivalent and that string will become the result of the pragma or 952** the error message if the pragma fails. ^If the 953** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 954** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 955** file control returns [SQLITE_OK], then the parser assumes that the 956** VFS has handled the PRAGMA itself and the parser generates a no-op 957** prepared statement if result string is NULL, or that returns a copy 958** of the result string if the string is non-NULL. 959** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 960** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 961** that the VFS encountered an error while handling the [PRAGMA] and the 962** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 963** file control occurs at the beginning of pragma statement analysis and so 964** it is able to override built-in [PRAGMA] statements. 965** 966** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 967** ^The [SQLITE_FCNTL_BUSYHANDLER] 968** file-control may be invoked by SQLite on the database file handle 969** shortly after it is opened in order to provide a custom VFS with access 970** to the connections busy-handler callback. The argument is of type (void **) 971** - an array of two (void *) values. The first (void *) actually points 972** to a function of type (int (*)(void *)). In order to invoke the connections 973** busy-handler, this function should be invoked with the second (void *) in 974** the array as the only argument. If it returns non-zero, then the operation 975** should be retried. If it returns zero, the custom VFS should abandon the 976** current operation. 977** 978** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 979** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 980** to have SQLite generate a 981** temporary filename using the same algorithm that is followed to generate 982** temporary filenames for TEMP tables and other internal uses. The 983** argument should be a char** which will be filled with the filename 984** written into memory obtained from [sqlite3_malloc()]. The caller should 985** invoke [sqlite3_free()] on the result to avoid a memory leak. 986** 987** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 988** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 989** maximum number of bytes that will be used for memory-mapped I/O. 990** The argument is a pointer to a value of type sqlite3_int64 that 991** is an advisory maximum number of bytes in the file to memory map. The 992** pointer is overwritten with the old value. The limit is not changed if 993** the value originally pointed to is negative, and so the current limit 994** can be queried by passing in a pointer to a negative number. This 995** file-control is used internally to implement [PRAGMA mmap_size]. 996** 997** <li>[[SQLITE_FCNTL_TRACE]] 998** The [SQLITE_FCNTL_TRACE] file control provides advisory information 999** to the VFS about what the higher layers of the SQLite stack are doing. 1000** This file control is used by some VFS activity tracing [shims]. 1001** The argument is a zero-terminated string. Higher layers in the 1002** SQLite stack may generate instances of this file control if 1003** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 1004** 1005** <li>[[SQLITE_FCNTL_HAS_MOVED]] 1006** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 1007** pointer to an integer and it writes a boolean into that integer depending 1008** on whether or not the file has been renamed, moved, or deleted since it 1009** was first opened. 1010** 1011** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]] 1012** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the 1013** underlying native file handle associated with a file handle. This file 1014** control interprets its argument as a pointer to a native file handle and 1015** writes the resulting value there. 1016** 1017** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 1018** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 1019** opcode causes the xFileControl method to swap the file handle with the one 1020** pointed to by the pArg argument. This capability is used during testing 1021** and only needs to be supported when SQLITE_TEST is defined. 1022** 1023** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 1024** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 1025** be advantageous to block on the next WAL lock if the lock is not immediately 1026** available. The WAL subsystem issues this signal during rare 1027** circumstances in order to fix a problem with priority inversion. 1028** Applications should <em>not</em> use this file-control. 1029** 1030** <li>[[SQLITE_FCNTL_ZIPVFS]] 1031** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 1032** VFS should return SQLITE_NOTFOUND for this opcode. 1033** 1034** <li>[[SQLITE_FCNTL_RBU]] 1035** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 1036** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 1037** this opcode. 1038** 1039** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]] 1040** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then 1041** the file descriptor is placed in "batch write mode", which 1042** means all subsequent write operations will be deferred and done 1043** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems 1044** that do not support batch atomic writes will return SQLITE_NOTFOUND. 1045** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to 1046** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or 1047** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make 1048** no VFS interface calls on the same [sqlite3_file] file descriptor 1049** except for calls to the xWrite method and the xFileControl method 1050** with [SQLITE_FCNTL_SIZE_HINT]. 1051** 1052** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]] 1053** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write 1054** operations since the previous successful call to 1055** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically. 1056** This file control returns [SQLITE_OK] if and only if the writes were 1057** all performed successfully and have been committed to persistent storage. 1058** ^Regardless of whether or not it is successful, this file control takes 1059** the file descriptor out of batch write mode so that all subsequent 1060** write operations are independent. 1061** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without 1062** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1063** 1064** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]] 1065** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write 1066** operations since the previous successful call to 1067** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back. 1068** ^This file control takes the file descriptor out of batch write mode 1069** so that all subsequent write operations are independent. 1070** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without 1071** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1072** 1073** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]] 1074** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode causes attempts to obtain 1075** a file lock using the xLock or xShmLock methods of the VFS to wait 1076** for up to M milliseconds before failing, where M is the single 1077** unsigned integer parameter. 1078** 1079** <li>[[SQLITE_FCNTL_DATA_VERSION]] 1080** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to 1081** a database file. The argument is a pointer to a 32-bit unsigned integer. 1082** The "data version" for the pager is written into the pointer. The 1083** "data version" changes whenever any change occurs to the corresponding 1084** database file, either through SQL statements on the same database 1085** connection or through transactions committed by separate database 1086** connections possibly in other processes. The [sqlite3_total_changes()] 1087** interface can be used to find if any database on the connection has changed, 1088** but that interface responds to changes on TEMP as well as MAIN and does 1089** not provide a mechanism to detect changes to MAIN only. Also, the 1090** [sqlite3_total_changes()] interface responds to internal changes only and 1091** omits changes made by other database connections. The 1092** [PRAGMA data_version] command provide a mechanism to detect changes to 1093** a single attached database that occur due to other database connections, 1094** but omits changes implemented by the database connection on which it is 1095** called. This file control is the only mechanism to detect changes that 1096** happen either internally or externally and that are associated with 1097** a particular attached database. 1098** </ul> 1099*/ 1100#define SQLITE_FCNTL_LOCKSTATE 1 1101#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1102#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1103#define SQLITE_FCNTL_LAST_ERRNO 4 1104#define SQLITE_FCNTL_SIZE_HINT 5 1105#define SQLITE_FCNTL_CHUNK_SIZE 6 1106#define SQLITE_FCNTL_FILE_POINTER 7 1107#define SQLITE_FCNTL_SYNC_OMITTED 8 1108#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1109#define SQLITE_FCNTL_PERSIST_WAL 10 1110#define SQLITE_FCNTL_OVERWRITE 11 1111#define SQLITE_FCNTL_VFSNAME 12 1112#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1113#define SQLITE_FCNTL_PRAGMA 14 1114#define SQLITE_FCNTL_BUSYHANDLER 15 1115#define SQLITE_FCNTL_TEMPFILENAME 16 1116#define SQLITE_FCNTL_MMAP_SIZE 18 1117#define SQLITE_FCNTL_TRACE 19 1118#define SQLITE_FCNTL_HAS_MOVED 20 1119#define SQLITE_FCNTL_SYNC 21 1120#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1121#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1122#define SQLITE_FCNTL_WAL_BLOCK 24 1123#define SQLITE_FCNTL_ZIPVFS 25 1124#define SQLITE_FCNTL_RBU 26 1125#define SQLITE_FCNTL_VFS_POINTER 27 1126#define SQLITE_FCNTL_JOURNAL_POINTER 28 1127#define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1128#define SQLITE_FCNTL_PDB 30 1129#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31 1130#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32 1131#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33 1132#define SQLITE_FCNTL_LOCK_TIMEOUT 34 1133#define SQLITE_FCNTL_DATA_VERSION 35 1134 1135/* deprecated names */ 1136#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1137#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1138#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1139 1140 1141/* 1142** CAPI3REF: Mutex Handle 1143** 1144** The mutex module within SQLite defines [sqlite3_mutex] to be an 1145** abstract type for a mutex object. The SQLite core never looks 1146** at the internal representation of an [sqlite3_mutex]. It only 1147** deals with pointers to the [sqlite3_mutex] object. 1148** 1149** Mutexes are created using [sqlite3_mutex_alloc()]. 1150*/ 1151typedef struct sqlite3_mutex sqlite3_mutex; 1152 1153/* 1154** CAPI3REF: Loadable Extension Thunk 1155** 1156** A pointer to the opaque sqlite3_api_routines structure is passed as 1157** the third parameter to entry points of [loadable extensions]. This 1158** structure must be typedefed in order to work around compiler warnings 1159** on some platforms. 1160*/ 1161typedef struct sqlite3_api_routines sqlite3_api_routines; 1162 1163/* 1164** CAPI3REF: OS Interface Object 1165** 1166** An instance of the sqlite3_vfs object defines the interface between 1167** the SQLite core and the underlying operating system. The "vfs" 1168** in the name of the object stands for "virtual file system". See 1169** the [VFS | VFS documentation] for further information. 1170** 1171** The VFS interface is sometimes extended by adding new methods onto 1172** the end. Each time such an extension occurs, the iVersion field 1173** is incremented. The iVersion value started out as 1 in 1174** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2 1175** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased 1176** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields 1177** may be appended to the sqlite3_vfs object and the iVersion value 1178** may increase again in future versions of SQLite. 1179** Note that the structure 1180** of the sqlite3_vfs object changes in the transition from 1181** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0] 1182** and yet the iVersion field was not modified. 1183** 1184** The szOsFile field is the size of the subclassed [sqlite3_file] 1185** structure used by this VFS. mxPathname is the maximum length of 1186** a pathname in this VFS. 1187** 1188** Registered sqlite3_vfs objects are kept on a linked list formed by 1189** the pNext pointer. The [sqlite3_vfs_register()] 1190** and [sqlite3_vfs_unregister()] interfaces manage this list 1191** in a thread-safe way. The [sqlite3_vfs_find()] interface 1192** searches the list. Neither the application code nor the VFS 1193** implementation should use the pNext pointer. 1194** 1195** The pNext field is the only field in the sqlite3_vfs 1196** structure that SQLite will ever modify. SQLite will only access 1197** or modify this field while holding a particular static mutex. 1198** The application should never modify anything within the sqlite3_vfs 1199** object once the object has been registered. 1200** 1201** The zName field holds the name of the VFS module. The name must 1202** be unique across all VFS modules. 1203** 1204** [[sqlite3_vfs.xOpen]] 1205** ^SQLite guarantees that the zFilename parameter to xOpen 1206** is either a NULL pointer or string obtained 1207** from xFullPathname() with an optional suffix added. 1208** ^If a suffix is added to the zFilename parameter, it will 1209** consist of a single "-" character followed by no more than 1210** 11 alphanumeric and/or "-" characters. 1211** ^SQLite further guarantees that 1212** the string will be valid and unchanged until xClose() is 1213** called. Because of the previous sentence, 1214** the [sqlite3_file] can safely store a pointer to the 1215** filename if it needs to remember the filename for some reason. 1216** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1217** must invent its own temporary name for the file. ^Whenever the 1218** xFilename parameter is NULL it will also be the case that the 1219** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1220** 1221** The flags argument to xOpen() includes all bits set in 1222** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1223** or [sqlite3_open16()] is used, then flags includes at least 1224** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1225** If xOpen() opens a file read-only then it sets *pOutFlags to 1226** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1227** 1228** ^(SQLite will also add one of the following flags to the xOpen() 1229** call, depending on the object being opened: 1230** 1231** <ul> 1232** <li> [SQLITE_OPEN_MAIN_DB] 1233** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1234** <li> [SQLITE_OPEN_TEMP_DB] 1235** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1236** <li> [SQLITE_OPEN_TRANSIENT_DB] 1237** <li> [SQLITE_OPEN_SUBJOURNAL] 1238** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1239** <li> [SQLITE_OPEN_WAL] 1240** </ul>)^ 1241** 1242** The file I/O implementation can use the object type flags to 1243** change the way it deals with files. For example, an application 1244** that does not care about crash recovery or rollback might make 1245** the open of a journal file a no-op. Writes to this journal would 1246** also be no-ops, and any attempt to read the journal would return 1247** SQLITE_IOERR. Or the implementation might recognize that a database 1248** file will be doing page-aligned sector reads and writes in a random 1249** order and set up its I/O subsystem accordingly. 1250** 1251** SQLite might also add one of the following flags to the xOpen method: 1252** 1253** <ul> 1254** <li> [SQLITE_OPEN_DELETEONCLOSE] 1255** <li> [SQLITE_OPEN_EXCLUSIVE] 1256** </ul> 1257** 1258** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1259** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1260** will be set for TEMP databases and their journals, transient 1261** databases, and subjournals. 1262** 1263** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1264** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1265** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1266** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1267** SQLITE_OPEN_CREATE, is used to indicate that file should always 1268** be created, and that it is an error if it already exists. 1269** It is <i>not</i> used to indicate the file should be opened 1270** for exclusive access. 1271** 1272** ^At least szOsFile bytes of memory are allocated by SQLite 1273** to hold the [sqlite3_file] structure passed as the third 1274** argument to xOpen. The xOpen method does not have to 1275** allocate the structure; it should just fill it in. Note that 1276** the xOpen method must set the sqlite3_file.pMethods to either 1277** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1278** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1279** element will be valid after xOpen returns regardless of the success 1280** or failure of the xOpen call. 1281** 1282** [[sqlite3_vfs.xAccess]] 1283** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1284** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1285** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1286** to test whether a file is at least readable. The file can be a 1287** directory. 1288** 1289** ^SQLite will always allocate at least mxPathname+1 bytes for the 1290** output buffer xFullPathname. The exact size of the output buffer 1291** is also passed as a parameter to both methods. If the output buffer 1292** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1293** handled as a fatal error by SQLite, vfs implementations should endeavor 1294** to prevent this by setting mxPathname to a sufficiently large value. 1295** 1296** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1297** interfaces are not strictly a part of the filesystem, but they are 1298** included in the VFS structure for completeness. 1299** The xRandomness() function attempts to return nBytes bytes 1300** of good-quality randomness into zOut. The return value is 1301** the actual number of bytes of randomness obtained. 1302** The xSleep() method causes the calling thread to sleep for at 1303** least the number of microseconds given. ^The xCurrentTime() 1304** method returns a Julian Day Number for the current date and time as 1305** a floating point value. 1306** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1307** Day Number multiplied by 86400000 (the number of milliseconds in 1308** a 24-hour day). 1309** ^SQLite will use the xCurrentTimeInt64() method to get the current 1310** date and time if that method is available (if iVersion is 2 or 1311** greater and the function pointer is not NULL) and will fall back 1312** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1313** 1314** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1315** are not used by the SQLite core. These optional interfaces are provided 1316** by some VFSes to facilitate testing of the VFS code. By overriding 1317** system calls with functions under its control, a test program can 1318** simulate faults and error conditions that would otherwise be difficult 1319** or impossible to induce. The set of system calls that can be overridden 1320** varies from one VFS to another, and from one version of the same VFS to the 1321** next. Applications that use these interfaces must be prepared for any 1322** or all of these interfaces to be NULL or for their behavior to change 1323** from one release to the next. Applications must not attempt to access 1324** any of these methods if the iVersion of the VFS is less than 3. 1325*/ 1326typedef struct sqlite3_vfs sqlite3_vfs; 1327typedef void (*sqlite3_syscall_ptr)(void); 1328struct sqlite3_vfs { 1329 int iVersion; /* Structure version number (currently 3) */ 1330 int szOsFile; /* Size of subclassed sqlite3_file */ 1331 int mxPathname; /* Maximum file pathname length */ 1332 sqlite3_vfs *pNext; /* Next registered VFS */ 1333 const char *zName; /* Name of this virtual file system */ 1334 void *pAppData; /* Pointer to application-specific data */ 1335 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1336 int flags, int *pOutFlags); 1337 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1338 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1339 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1340 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1341 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1342 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1343 void (*xDlClose)(sqlite3_vfs*, void*); 1344 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1345 int (*xSleep)(sqlite3_vfs*, int microseconds); 1346 int (*xCurrentTime)(sqlite3_vfs*, double*); 1347 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1348 /* 1349 ** The methods above are in version 1 of the sqlite_vfs object 1350 ** definition. Those that follow are added in version 2 or later 1351 */ 1352 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1353 /* 1354 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1355 ** Those below are for version 3 and greater. 1356 */ 1357 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1358 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1359 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1360 /* 1361 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1362 ** New fields may be appended in future versions. The iVersion 1363 ** value will increment whenever this happens. 1364 */ 1365}; 1366 1367/* 1368** CAPI3REF: Flags for the xAccess VFS method 1369** 1370** These integer constants can be used as the third parameter to 1371** the xAccess method of an [sqlite3_vfs] object. They determine 1372** what kind of permissions the xAccess method is looking for. 1373** With SQLITE_ACCESS_EXISTS, the xAccess method 1374** simply checks whether the file exists. 1375** With SQLITE_ACCESS_READWRITE, the xAccess method 1376** checks whether the named directory is both readable and writable 1377** (in other words, if files can be added, removed, and renamed within 1378** the directory). 1379** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1380** [temp_store_directory pragma], though this could change in a future 1381** release of SQLite. 1382** With SQLITE_ACCESS_READ, the xAccess method 1383** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1384** currently unused, though it might be used in a future release of 1385** SQLite. 1386*/ 1387#define SQLITE_ACCESS_EXISTS 0 1388#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1389#define SQLITE_ACCESS_READ 2 /* Unused */ 1390 1391/* 1392** CAPI3REF: Flags for the xShmLock VFS method 1393** 1394** These integer constants define the various locking operations 1395** allowed by the xShmLock method of [sqlite3_io_methods]. The 1396** following are the only legal combinations of flags to the 1397** xShmLock method: 1398** 1399** <ul> 1400** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1401** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1402** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1403** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1404** </ul> 1405** 1406** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1407** was given on the corresponding lock. 1408** 1409** The xShmLock method can transition between unlocked and SHARED or 1410** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1411** and EXCLUSIVE. 1412*/ 1413#define SQLITE_SHM_UNLOCK 1 1414#define SQLITE_SHM_LOCK 2 1415#define SQLITE_SHM_SHARED 4 1416#define SQLITE_SHM_EXCLUSIVE 8 1417 1418/* 1419** CAPI3REF: Maximum xShmLock index 1420** 1421** The xShmLock method on [sqlite3_io_methods] may use values 1422** between 0 and this upper bound as its "offset" argument. 1423** The SQLite core will never attempt to acquire or release a 1424** lock outside of this range 1425*/ 1426#define SQLITE_SHM_NLOCK 8 1427 1428 1429/* 1430** CAPI3REF: Initialize The SQLite Library 1431** 1432** ^The sqlite3_initialize() routine initializes the 1433** SQLite library. ^The sqlite3_shutdown() routine 1434** deallocates any resources that were allocated by sqlite3_initialize(). 1435** These routines are designed to aid in process initialization and 1436** shutdown on embedded systems. Workstation applications using 1437** SQLite normally do not need to invoke either of these routines. 1438** 1439** A call to sqlite3_initialize() is an "effective" call if it is 1440** the first time sqlite3_initialize() is invoked during the lifetime of 1441** the process, or if it is the first time sqlite3_initialize() is invoked 1442** following a call to sqlite3_shutdown(). ^(Only an effective call 1443** of sqlite3_initialize() does any initialization. All other calls 1444** are harmless no-ops.)^ 1445** 1446** A call to sqlite3_shutdown() is an "effective" call if it is the first 1447** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1448** an effective call to sqlite3_shutdown() does any deinitialization. 1449** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1450** 1451** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1452** is not. The sqlite3_shutdown() interface must only be called from a 1453** single thread. All open [database connections] must be closed and all 1454** other SQLite resources must be deallocated prior to invoking 1455** sqlite3_shutdown(). 1456** 1457** Among other things, ^sqlite3_initialize() will invoke 1458** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1459** will invoke sqlite3_os_end(). 1460** 1461** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1462** ^If for some reason, sqlite3_initialize() is unable to initialize 1463** the library (perhaps it is unable to allocate a needed resource such 1464** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1465** 1466** ^The sqlite3_initialize() routine is called internally by many other 1467** SQLite interfaces so that an application usually does not need to 1468** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1469** calls sqlite3_initialize() so the SQLite library will be automatically 1470** initialized when [sqlite3_open()] is called if it has not be initialized 1471** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1472** compile-time option, then the automatic calls to sqlite3_initialize() 1473** are omitted and the application must call sqlite3_initialize() directly 1474** prior to using any other SQLite interface. For maximum portability, 1475** it is recommended that applications always invoke sqlite3_initialize() 1476** directly prior to using any other SQLite interface. Future releases 1477** of SQLite may require this. In other words, the behavior exhibited 1478** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1479** default behavior in some future release of SQLite. 1480** 1481** The sqlite3_os_init() routine does operating-system specific 1482** initialization of the SQLite library. The sqlite3_os_end() 1483** routine undoes the effect of sqlite3_os_init(). Typical tasks 1484** performed by these routines include allocation or deallocation 1485** of static resources, initialization of global variables, 1486** setting up a default [sqlite3_vfs] module, or setting up 1487** a default configuration using [sqlite3_config()]. 1488** 1489** The application should never invoke either sqlite3_os_init() 1490** or sqlite3_os_end() directly. The application should only invoke 1491** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1492** interface is called automatically by sqlite3_initialize() and 1493** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1494** implementations for sqlite3_os_init() and sqlite3_os_end() 1495** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1496** When [custom builds | built for other platforms] 1497** (using the [SQLITE_OS_OTHER=1] compile-time 1498** option) the application must supply a suitable implementation for 1499** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1500** implementation of sqlite3_os_init() or sqlite3_os_end() 1501** must return [SQLITE_OK] on success and some other [error code] upon 1502** failure. 1503*/ 1504int sqlite3_initialize(void); 1505int sqlite3_shutdown(void); 1506int sqlite3_os_init(void); 1507int sqlite3_os_end(void); 1508 1509/* 1510** CAPI3REF: Configuring The SQLite Library 1511** 1512** The sqlite3_config() interface is used to make global configuration 1513** changes to SQLite in order to tune SQLite to the specific needs of 1514** the application. The default configuration is recommended for most 1515** applications and so this routine is usually not necessary. It is 1516** provided to support rare applications with unusual needs. 1517** 1518** <b>The sqlite3_config() interface is not threadsafe. The application 1519** must ensure that no other SQLite interfaces are invoked by other 1520** threads while sqlite3_config() is running.</b> 1521** 1522** The sqlite3_config() interface 1523** may only be invoked prior to library initialization using 1524** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1525** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1526** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1527** Note, however, that ^sqlite3_config() can be called as part of the 1528** implementation of an application-defined [sqlite3_os_init()]. 1529** 1530** The first argument to sqlite3_config() is an integer 1531** [configuration option] that determines 1532** what property of SQLite is to be configured. Subsequent arguments 1533** vary depending on the [configuration option] 1534** in the first argument. 1535** 1536** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1537** ^If the option is unknown or SQLite is unable to set the option 1538** then this routine returns a non-zero [error code]. 1539*/ 1540int sqlite3_config(int, ...); 1541 1542/* 1543** CAPI3REF: Configure database connections 1544** METHOD: sqlite3 1545** 1546** The sqlite3_db_config() interface is used to make configuration 1547** changes to a [database connection]. The interface is similar to 1548** [sqlite3_config()] except that the changes apply to a single 1549** [database connection] (specified in the first argument). 1550** 1551** The second argument to sqlite3_db_config(D,V,...) is the 1552** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1553** that indicates what aspect of the [database connection] is being configured. 1554** Subsequent arguments vary depending on the configuration verb. 1555** 1556** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1557** the call is considered successful. 1558*/ 1559int sqlite3_db_config(sqlite3*, int op, ...); 1560 1561/* 1562** CAPI3REF: Memory Allocation Routines 1563** 1564** An instance of this object defines the interface between SQLite 1565** and low-level memory allocation routines. 1566** 1567** This object is used in only one place in the SQLite interface. 1568** A pointer to an instance of this object is the argument to 1569** [sqlite3_config()] when the configuration option is 1570** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1571** By creating an instance of this object 1572** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1573** during configuration, an application can specify an alternative 1574** memory allocation subsystem for SQLite to use for all of its 1575** dynamic memory needs. 1576** 1577** Note that SQLite comes with several [built-in memory allocators] 1578** that are perfectly adequate for the overwhelming majority of applications 1579** and that this object is only useful to a tiny minority of applications 1580** with specialized memory allocation requirements. This object is 1581** also used during testing of SQLite in order to specify an alternative 1582** memory allocator that simulates memory out-of-memory conditions in 1583** order to verify that SQLite recovers gracefully from such 1584** conditions. 1585** 1586** The xMalloc, xRealloc, and xFree methods must work like the 1587** malloc(), realloc() and free() functions from the standard C library. 1588** ^SQLite guarantees that the second argument to 1589** xRealloc is always a value returned by a prior call to xRoundup. 1590** 1591** xSize should return the allocated size of a memory allocation 1592** previously obtained from xMalloc or xRealloc. The allocated size 1593** is always at least as big as the requested size but may be larger. 1594** 1595** The xRoundup method returns what would be the allocated size of 1596** a memory allocation given a particular requested size. Most memory 1597** allocators round up memory allocations at least to the next multiple 1598** of 8. Some allocators round up to a larger multiple or to a power of 2. 1599** Every memory allocation request coming in through [sqlite3_malloc()] 1600** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1601** that causes the corresponding memory allocation to fail. 1602** 1603** The xInit method initializes the memory allocator. For example, 1604** it might allocate any require mutexes or initialize internal data 1605** structures. The xShutdown method is invoked (indirectly) by 1606** [sqlite3_shutdown()] and should deallocate any resources acquired 1607** by xInit. The pAppData pointer is used as the only parameter to 1608** xInit and xShutdown. 1609** 1610** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1611** the xInit method, so the xInit method need not be threadsafe. The 1612** xShutdown method is only called from [sqlite3_shutdown()] so it does 1613** not need to be threadsafe either. For all other methods, SQLite 1614** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1615** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1616** it is by default) and so the methods are automatically serialized. 1617** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1618** methods must be threadsafe or else make their own arrangements for 1619** serialization. 1620** 1621** SQLite will never invoke xInit() more than once without an intervening 1622** call to xShutdown(). 1623*/ 1624typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1625struct sqlite3_mem_methods { 1626 void *(*xMalloc)(int); /* Memory allocation function */ 1627 void (*xFree)(void*); /* Free a prior allocation */ 1628 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1629 int (*xSize)(void*); /* Return the size of an allocation */ 1630 int (*xRoundup)(int); /* Round up request size to allocation size */ 1631 int (*xInit)(void*); /* Initialize the memory allocator */ 1632 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1633 void *pAppData; /* Argument to xInit() and xShutdown() */ 1634}; 1635 1636/* 1637** CAPI3REF: Configuration Options 1638** KEYWORDS: {configuration option} 1639** 1640** These constants are the available integer configuration options that 1641** can be passed as the first argument to the [sqlite3_config()] interface. 1642** 1643** New configuration options may be added in future releases of SQLite. 1644** Existing configuration options might be discontinued. Applications 1645** should check the return code from [sqlite3_config()] to make sure that 1646** the call worked. The [sqlite3_config()] interface will return a 1647** non-zero [error code] if a discontinued or unsupported configuration option 1648** is invoked. 1649** 1650** <dl> 1651** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1652** <dd>There are no arguments to this option. ^This option sets the 1653** [threading mode] to Single-thread. In other words, it disables 1654** all mutexing and puts SQLite into a mode where it can only be used 1655** by a single thread. ^If SQLite is compiled with 1656** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1657** it is not possible to change the [threading mode] from its default 1658** value of Single-thread and so [sqlite3_config()] will return 1659** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1660** configuration option.</dd> 1661** 1662** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1663** <dd>There are no arguments to this option. ^This option sets the 1664** [threading mode] to Multi-thread. In other words, it disables 1665** mutexing on [database connection] and [prepared statement] objects. 1666** The application is responsible for serializing access to 1667** [database connections] and [prepared statements]. But other mutexes 1668** are enabled so that SQLite will be safe to use in a multi-threaded 1669** environment as long as no two threads attempt to use the same 1670** [database connection] at the same time. ^If SQLite is compiled with 1671** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1672** it is not possible to set the Multi-thread [threading mode] and 1673** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1674** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1675** 1676** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1677** <dd>There are no arguments to this option. ^This option sets the 1678** [threading mode] to Serialized. In other words, this option enables 1679** all mutexes including the recursive 1680** mutexes on [database connection] and [prepared statement] objects. 1681** In this mode (which is the default when SQLite is compiled with 1682** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1683** to [database connections] and [prepared statements] so that the 1684** application is free to use the same [database connection] or the 1685** same [prepared statement] in different threads at the same time. 1686** ^If SQLite is compiled with 1687** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1688** it is not possible to set the Serialized [threading mode] and 1689** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1690** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1691** 1692** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1693** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1694** a pointer to an instance of the [sqlite3_mem_methods] structure. 1695** The argument specifies 1696** alternative low-level memory allocation routines to be used in place of 1697** the memory allocation routines built into SQLite.)^ ^SQLite makes 1698** its own private copy of the content of the [sqlite3_mem_methods] structure 1699** before the [sqlite3_config()] call returns.</dd> 1700** 1701** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1702** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1703** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1704** The [sqlite3_mem_methods] 1705** structure is filled with the currently defined memory allocation routines.)^ 1706** This option can be used to overload the default memory allocation 1707** routines with a wrapper that simulations memory allocation failure or 1708** tracks memory usage, for example. </dd> 1709** 1710** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt> 1711** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of 1712** type int, interpreted as a boolean, which if true provides a hint to 1713** SQLite that it should avoid large memory allocations if possible. 1714** SQLite will run faster if it is free to make large memory allocations, 1715** but some application might prefer to run slower in exchange for 1716** guarantees about memory fragmentation that are possible if large 1717** allocations are avoided. This hint is normally off. 1718** </dd> 1719** 1720** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1721** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1722** interpreted as a boolean, which enables or disables the collection of 1723** memory allocation statistics. ^(When memory allocation statistics are 1724** disabled, the following SQLite interfaces become non-operational: 1725** <ul> 1726** <li> [sqlite3_memory_used()] 1727** <li> [sqlite3_memory_highwater()] 1728** <li> [sqlite3_soft_heap_limit64()] 1729** <li> [sqlite3_status64()] 1730** </ul>)^ 1731** ^Memory allocation statistics are enabled by default unless SQLite is 1732** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1733** allocation statistics are disabled by default. 1734** </dd> 1735** 1736** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1737** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used. 1738** </dd> 1739** 1740** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1741** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1742** that SQLite can use for the database page cache with the default page 1743** cache implementation. 1744** This configuration option is a no-op if an application-define page 1745** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1746** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1747** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1748** and the number of cache lines (N). 1749** The sz argument should be the size of the largest database page 1750** (a power of two between 512 and 65536) plus some extra bytes for each 1751** page header. ^The number of extra bytes needed by the page header 1752** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1753** ^It is harmless, apart from the wasted memory, 1754** for the sz parameter to be larger than necessary. The pMem 1755** argument must be either a NULL pointer or a pointer to an 8-byte 1756** aligned block of memory of at least sz*N bytes, otherwise 1757** subsequent behavior is undefined. 1758** ^When pMem is not NULL, SQLite will strive to use the memory provided 1759** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1760** a page cache line is larger than sz bytes or if all of the pMem buffer 1761** is exhausted. 1762** ^If pMem is NULL and N is non-zero, then each database connection 1763** does an initial bulk allocation for page cache memory 1764** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1765** of -1024*N bytes if N is negative, . ^If additional 1766** page cache memory is needed beyond what is provided by the initial 1767** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1768** additional cache line. </dd> 1769** 1770** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1771** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1772** that SQLite will use for all of its dynamic memory allocation needs 1773** beyond those provided for by [SQLITE_CONFIG_PAGECACHE]. 1774** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1775** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1776** [SQLITE_ERROR] if invoked otherwise. 1777** ^There are three arguments to SQLITE_CONFIG_HEAP: 1778** An 8-byte aligned pointer to the memory, 1779** the number of bytes in the memory buffer, and the minimum allocation size. 1780** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1781** to using its default memory allocator (the system malloc() implementation), 1782** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1783** memory pointer is not NULL then the alternative memory 1784** allocator is engaged to handle all of SQLites memory allocation needs. 1785** The first pointer (the memory pointer) must be aligned to an 8-byte 1786** boundary or subsequent behavior of SQLite will be undefined. 1787** The minimum allocation size is capped at 2**12. Reasonable values 1788** for the minimum allocation size are 2**5 through 2**8.</dd> 1789** 1790** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1791** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1792** pointer to an instance of the [sqlite3_mutex_methods] structure. 1793** The argument specifies alternative low-level mutex routines to be used 1794** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1795** the content of the [sqlite3_mutex_methods] structure before the call to 1796** [sqlite3_config()] returns. ^If SQLite is compiled with 1797** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1798** the entire mutexing subsystem is omitted from the build and hence calls to 1799** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1800** return [SQLITE_ERROR].</dd> 1801** 1802** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1803** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1804** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1805** [sqlite3_mutex_methods] 1806** structure is filled with the currently defined mutex routines.)^ 1807** This option can be used to overload the default mutex allocation 1808** routines with a wrapper used to track mutex usage for performance 1809** profiling or testing, for example. ^If SQLite is compiled with 1810** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1811** the entire mutexing subsystem is omitted from the build and hence calls to 1812** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1813** return [SQLITE_ERROR].</dd> 1814** 1815** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1816** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1817** the default size of lookaside memory on each [database connection]. 1818** The first argument is the 1819** size of each lookaside buffer slot and the second is the number of 1820** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1821** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1822** option to [sqlite3_db_config()] can be used to change the lookaside 1823** configuration on individual connections.)^ </dd> 1824** 1825** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1826** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1827** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1828** the interface to a custom page cache implementation.)^ 1829** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1830** 1831** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1832** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1833** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1834** the current page cache implementation into that object.)^ </dd> 1835** 1836** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1837** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1838** global [error log]. 1839** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1840** function with a call signature of void(*)(void*,int,const char*), 1841** and a pointer to void. ^If the function pointer is not NULL, it is 1842** invoked by [sqlite3_log()] to process each logging event. ^If the 1843** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1844** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1845** passed through as the first parameter to the application-defined logger 1846** function whenever that function is invoked. ^The second parameter to 1847** the logger function is a copy of the first parameter to the corresponding 1848** [sqlite3_log()] call and is intended to be a [result code] or an 1849** [extended result code]. ^The third parameter passed to the logger is 1850** log message after formatting via [sqlite3_snprintf()]. 1851** The SQLite logging interface is not reentrant; the logger function 1852** supplied by the application must not invoke any SQLite interface. 1853** In a multi-threaded application, the application-defined logger 1854** function must be threadsafe. </dd> 1855** 1856** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1857** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1858** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1859** then URI handling is globally disabled.)^ ^If URI handling is globally 1860** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1861** [sqlite3_open16()] or 1862** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1863** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1864** connection is opened. ^If it is globally disabled, filenames are 1865** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1866** database connection is opened. ^(By default, URI handling is globally 1867** disabled. The default value may be changed by compiling with the 1868** [SQLITE_USE_URI] symbol defined.)^ 1869** 1870** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1871** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1872** argument which is interpreted as a boolean in order to enable or disable 1873** the use of covering indices for full table scans in the query optimizer. 1874** ^The default setting is determined 1875** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1876** if that compile-time option is omitted. 1877** The ability to disable the use of covering indices for full table scans 1878** is because some incorrectly coded legacy applications might malfunction 1879** when the optimization is enabled. Providing the ability to 1880** disable the optimization allows the older, buggy application code to work 1881** without change even with newer versions of SQLite. 1882** 1883** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1884** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1885** <dd> These options are obsolete and should not be used by new code. 1886** They are retained for backwards compatibility but are now no-ops. 1887** </dd> 1888** 1889** [[SQLITE_CONFIG_SQLLOG]] 1890** <dt>SQLITE_CONFIG_SQLLOG 1891** <dd>This option is only available if sqlite is compiled with the 1892** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1893** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1894** The second should be of type (void*). The callback is invoked by the library 1895** in three separate circumstances, identified by the value passed as the 1896** fourth parameter. If the fourth parameter is 0, then the database connection 1897** passed as the second argument has just been opened. The third argument 1898** points to a buffer containing the name of the main database file. If the 1899** fourth parameter is 1, then the SQL statement that the third parameter 1900** points to has just been executed. Or, if the fourth parameter is 2, then 1901** the connection being passed as the second parameter is being closed. The 1902** third parameter is passed NULL In this case. An example of using this 1903** configuration option can be seen in the "test_sqllog.c" source file in 1904** the canonical SQLite source tree.</dd> 1905** 1906** [[SQLITE_CONFIG_MMAP_SIZE]] 1907** <dt>SQLITE_CONFIG_MMAP_SIZE 1908** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1909** that are the default mmap size limit (the default setting for 1910** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1911** ^The default setting can be overridden by each database connection using 1912** either the [PRAGMA mmap_size] command, or by using the 1913** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1914** will be silently truncated if necessary so that it does not exceed the 1915** compile-time maximum mmap size set by the 1916** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1917** ^If either argument to this option is negative, then that argument is 1918** changed to its compile-time default. 1919** 1920** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1921** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1922** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1923** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1924** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1925** that specifies the maximum size of the created heap. 1926** 1927** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1928** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1929** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1930** is a pointer to an integer and writes into that integer the number of extra 1931** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1932** The amount of extra space required can change depending on the compiler, 1933** target platform, and SQLite version. 1934** 1935** [[SQLITE_CONFIG_PMASZ]] 1936** <dt>SQLITE_CONFIG_PMASZ 1937** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1938** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1939** sorter to that integer. The default minimum PMA Size is set by the 1940** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1941** to help with sort operations when multithreaded sorting 1942** is enabled (using the [PRAGMA threads] command) and the amount of content 1943** to be sorted exceeds the page size times the minimum of the 1944** [PRAGMA cache_size] setting and this value. 1945** 1946** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 1947** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 1948** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 1949** becomes the [statement journal] spill-to-disk threshold. 1950** [Statement journals] are held in memory until their size (in bytes) 1951** exceeds this threshold, at which point they are written to disk. 1952** Or if the threshold is -1, statement journals are always held 1953** exclusively in memory. 1954** Since many statement journals never become large, setting the spill 1955** threshold to a value such as 64KiB can greatly reduce the amount of 1956** I/O required to support statement rollback. 1957** The default value for this setting is controlled by the 1958** [SQLITE_STMTJRNL_SPILL] compile-time option. 1959** 1960** [[SQLITE_CONFIG_SORTERREF_SIZE]] 1961** <dt>SQLITE_CONFIG_SORTERREF_SIZE 1962** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter 1963** of type (int) - the new value of the sorter-reference size threshold. 1964** Usually, when SQLite uses an external sort to order records according 1965** to an ORDER BY clause, all fields required by the caller are present in the 1966** sorted records. However, if SQLite determines based on the declared type 1967** of a table column that its values are likely to be very large - larger 1968** than the configured sorter-reference size threshold - then a reference 1969** is stored in each sorted record and the required column values loaded 1970** from the database as records are returned in sorted order. The default 1971** value for this option is to never use this optimization. Specifying a 1972** negative value for this option restores the default behaviour. 1973** This option is only available if SQLite is compiled with the 1974** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option. 1975** </dl> 1976*/ 1977#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1978#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1979#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1980#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1981#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1982#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */ 1983#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1984#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1985#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1986#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1987#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1988/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1989#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1990#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1991#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1992#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1993#define SQLITE_CONFIG_URI 17 /* int */ 1994#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1995#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1996#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1997#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1998#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1999#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 2000#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 2001#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 2002#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 2003#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */ 2004#define SQLITE_CONFIG_SORTERREF_SIZE 28 /* int nByte */ 2005 2006/* 2007** CAPI3REF: Database Connection Configuration Options 2008** 2009** These constants are the available integer configuration options that 2010** can be passed as the second argument to the [sqlite3_db_config()] interface. 2011** 2012** New configuration options may be added in future releases of SQLite. 2013** Existing configuration options might be discontinued. Applications 2014** should check the return code from [sqlite3_db_config()] to make sure that 2015** the call worked. ^The [sqlite3_db_config()] interface will return a 2016** non-zero [error code] if a discontinued or unsupported configuration option 2017** is invoked. 2018** 2019** <dl> 2020** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 2021** <dd> ^This option takes three additional arguments that determine the 2022** [lookaside memory allocator] configuration for the [database connection]. 2023** ^The first argument (the third parameter to [sqlite3_db_config()] is a 2024** pointer to a memory buffer to use for lookaside memory. 2025** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 2026** may be NULL in which case SQLite will allocate the 2027** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 2028** size of each lookaside buffer slot. ^The third argument is the number of 2029** slots. The size of the buffer in the first argument must be greater than 2030** or equal to the product of the second and third arguments. The buffer 2031** must be aligned to an 8-byte boundary. ^If the second argument to 2032** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 2033** rounded down to the next smaller multiple of 8. ^(The lookaside memory 2034** configuration for a database connection can only be changed when that 2035** connection is not currently using lookaside memory, or in other words 2036** when the "current value" returned by 2037** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 2038** Any attempt to change the lookaside memory configuration when lookaside 2039** memory is in use leaves the configuration unchanged and returns 2040** [SQLITE_BUSY].)^</dd> 2041** 2042** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 2043** <dd> ^This option is used to enable or disable the enforcement of 2044** [foreign key constraints]. There should be two additional arguments. 2045** The first argument is an integer which is 0 to disable FK enforcement, 2046** positive to enable FK enforcement or negative to leave FK enforcement 2047** unchanged. The second parameter is a pointer to an integer into which 2048** is written 0 or 1 to indicate whether FK enforcement is off or on 2049** following this call. The second parameter may be a NULL pointer, in 2050** which case the FK enforcement setting is not reported back. </dd> 2051** 2052** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 2053** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 2054** There should be two additional arguments. 2055** The first argument is an integer which is 0 to disable triggers, 2056** positive to enable triggers or negative to leave the setting unchanged. 2057** The second parameter is a pointer to an integer into which 2058** is written 0 or 1 to indicate whether triggers are disabled or enabled 2059** following this call. The second parameter may be a NULL pointer, in 2060** which case the trigger setting is not reported back. </dd> 2061** 2062** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 2063** <dd> ^This option is used to enable or disable the two-argument 2064** version of the [fts3_tokenizer()] function which is part of the 2065** [FTS3] full-text search engine extension. 2066** There should be two additional arguments. 2067** The first argument is an integer which is 0 to disable fts3_tokenizer() or 2068** positive to enable fts3_tokenizer() or negative to leave the setting 2069** unchanged. 2070** The second parameter is a pointer to an integer into which 2071** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 2072** following this call. The second parameter may be a NULL pointer, in 2073** which case the new setting is not reported back. </dd> 2074** 2075** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 2076** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 2077** interface independently of the [load_extension()] SQL function. 2078** The [sqlite3_enable_load_extension()] API enables or disables both the 2079** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 2080** There should be two additional arguments. 2081** When the first argument to this interface is 1, then only the C-API is 2082** enabled and the SQL function remains disabled. If the first argument to 2083** this interface is 0, then both the C-API and the SQL function are disabled. 2084** If the first argument is -1, then no changes are made to state of either the 2085** C-API or the SQL function. 2086** The second parameter is a pointer to an integer into which 2087** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 2088** is disabled or enabled following this call. The second parameter may 2089** be a NULL pointer, in which case the new setting is not reported back. 2090** </dd> 2091** 2092** <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 2093** <dd> ^This option is used to change the name of the "main" database 2094** schema. ^The sole argument is a pointer to a constant UTF8 string 2095** which will become the new schema name in place of "main". ^SQLite 2096** does not make a copy of the new main schema name string, so the application 2097** must ensure that the argument passed into this DBCONFIG option is unchanged 2098** until after the database connection closes. 2099** </dd> 2100** 2101** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 2102** <dd> Usually, when a database in wal mode is closed or detached from a 2103** database handle, SQLite checks if this will mean that there are now no 2104** connections at all to the database. If so, it performs a checkpoint 2105** operation before closing the connection. This option may be used to 2106** override this behaviour. The first parameter passed to this operation 2107** is an integer - positive to disable checkpoints-on-close, or zero (the 2108** default) to enable them, and negative to leave the setting unchanged. 2109** The second parameter is a pointer to an integer 2110** into which is written 0 or 1 to indicate whether checkpoints-on-close 2111** have been disabled - 0 if they are not disabled, 1 if they are. 2112** </dd> 2113** 2114** <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2115** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2116** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2117** a single SQL query statement will always use the same algorithm regardless 2118** of values of [bound parameters].)^ The QPSG disables some query optimizations 2119** that look at the values of bound parameters, which can make some queries 2120** slower. But the QPSG has the advantage of more predictable behavior. With 2121** the QPSG active, SQLite will always use the same query plan in the field as 2122** was used during testing in the lab. 2123** The first argument to this setting is an integer which is 0 to disable 2124** the QPSG, positive to enable QPSG, or negative to leave the setting 2125** unchanged. The second parameter is a pointer to an integer into which 2126** is written 0 or 1 to indicate whether the QPSG is disabled or enabled 2127** following this call. 2128** </dd> 2129** 2130** <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt> 2131** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not 2132** include output for any operations performed by trigger programs. This 2133** option is used to set or clear (the default) a flag that governs this 2134** behavior. The first parameter passed to this operation is an integer - 2135** positive to enable output for trigger programs, or zero to disable it, 2136** or negative to leave the setting unchanged. 2137** The second parameter is a pointer to an integer into which is written 2138** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if 2139** it is not disabled, 1 if it is. 2140** </dd> 2141** 2142** <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt> 2143** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run 2144** [VACUUM] in order to reset a database back to an empty database 2145** with no schema and no content. The following process works even for 2146** a badly corrupted database file: 2147** <ol> 2148** <li> If the database connection is newly opened, make sure it has read the 2149** database schema by preparing then discarding some query against the 2150** database, or calling sqlite3_table_column_metadata(), ignoring any 2151** errors. This step is only necessary if the application desires to keep 2152** the database in WAL mode after the reset if it was in WAL mode before 2153** the reset. 2154** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0); 2155** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0); 2156** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0); 2157** </ol> 2158** Because resetting a database is destructive and irreversible, the 2159** process requires the use of this obscure API and multiple steps to help 2160** ensure that it does not happen by accident. 2161** </dd> 2162** </dl> 2163*/ 2164#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2165#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2166#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2167#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2168#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2169#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2170#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2171#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2172#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */ 2173#define SQLITE_DBCONFIG_RESET_DATABASE 1009 /* int int* */ 2174#define SQLITE_DBCONFIG_MAX 1009 /* Largest DBCONFIG */ 2175 2176/* 2177** CAPI3REF: Enable Or Disable Extended Result Codes 2178** METHOD: sqlite3 2179** 2180** ^The sqlite3_extended_result_codes() routine enables or disables the 2181** [extended result codes] feature of SQLite. ^The extended result 2182** codes are disabled by default for historical compatibility. 2183*/ 2184int sqlite3_extended_result_codes(sqlite3*, int onoff); 2185 2186/* 2187** CAPI3REF: Last Insert Rowid 2188** METHOD: sqlite3 2189** 2190** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2191** has a unique 64-bit signed 2192** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2193** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2194** names are not also used by explicitly declared columns. ^If 2195** the table has a column of type [INTEGER PRIMARY KEY] then that column 2196** is another alias for the rowid. 2197** 2198** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2199** the most recent successful [INSERT] into a rowid table or [virtual table] 2200** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2201** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2202** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2203** zero. 2204** 2205** As well as being set automatically as rows are inserted into database 2206** tables, the value returned by this function may be set explicitly by 2207** [sqlite3_set_last_insert_rowid()] 2208** 2209** Some virtual table implementations may INSERT rows into rowid tables as 2210** part of committing a transaction (e.g. to flush data accumulated in memory 2211** to disk). In this case subsequent calls to this function return the rowid 2212** associated with these internal INSERT operations, which leads to 2213** unintuitive results. Virtual table implementations that do write to rowid 2214** tables in this way can avoid this problem by restoring the original 2215** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2216** control to the user. 2217** 2218** ^(If an [INSERT] occurs within a trigger then this routine will 2219** return the [rowid] of the inserted row as long as the trigger is 2220** running. Once the trigger program ends, the value returned 2221** by this routine reverts to what it was before the trigger was fired.)^ 2222** 2223** ^An [INSERT] that fails due to a constraint violation is not a 2224** successful [INSERT] and does not change the value returned by this 2225** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2226** and INSERT OR ABORT make no changes to the return value of this 2227** routine when their insertion fails. ^(When INSERT OR REPLACE 2228** encounters a constraint violation, it does not fail. The 2229** INSERT continues to completion after deleting rows that caused 2230** the constraint problem so INSERT OR REPLACE will always change 2231** the return value of this interface.)^ 2232** 2233** ^For the purposes of this routine, an [INSERT] is considered to 2234** be successful even if it is subsequently rolled back. 2235** 2236** This function is accessible to SQL statements via the 2237** [last_insert_rowid() SQL function]. 2238** 2239** If a separate thread performs a new [INSERT] on the same 2240** database connection while the [sqlite3_last_insert_rowid()] 2241** function is running and thus changes the last insert [rowid], 2242** then the value returned by [sqlite3_last_insert_rowid()] is 2243** unpredictable and might not equal either the old or the new 2244** last insert [rowid]. 2245*/ 2246sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2247 2248/* 2249** CAPI3REF: Set the Last Insert Rowid value. 2250** METHOD: sqlite3 2251** 2252** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2253** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2254** without inserting a row into the database. 2255*/ 2256void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2257 2258/* 2259** CAPI3REF: Count The Number Of Rows Modified 2260** METHOD: sqlite3 2261** 2262** ^This function returns the number of rows modified, inserted or 2263** deleted by the most recently completed INSERT, UPDATE or DELETE 2264** statement on the database connection specified by the only parameter. 2265** ^Executing any other type of SQL statement does not modify the value 2266** returned by this function. 2267** 2268** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2269** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2270** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2271** 2272** Changes to a view that are intercepted by 2273** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2274** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2275** DELETE statement run on a view is always zero. Only changes made to real 2276** tables are counted. 2277** 2278** Things are more complicated if the sqlite3_changes() function is 2279** executed while a trigger program is running. This may happen if the 2280** program uses the [changes() SQL function], or if some other callback 2281** function invokes sqlite3_changes() directly. Essentially: 2282** 2283** <ul> 2284** <li> ^(Before entering a trigger program the value returned by 2285** sqlite3_changes() function is saved. After the trigger program 2286** has finished, the original value is restored.)^ 2287** 2288** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2289** statement sets the value returned by sqlite3_changes() 2290** upon completion as normal. Of course, this value will not include 2291** any changes performed by sub-triggers, as the sqlite3_changes() 2292** value will be saved and restored after each sub-trigger has run.)^ 2293** </ul> 2294** 2295** ^This means that if the changes() SQL function (or similar) is used 2296** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2297** returns the value as set when the calling statement began executing. 2298** ^If it is used by the second or subsequent such statement within a trigger 2299** program, the value returned reflects the number of rows modified by the 2300** previous INSERT, UPDATE or DELETE statement within the same trigger. 2301** 2302** If a separate thread makes changes on the same database connection 2303** while [sqlite3_changes()] is running then the value returned 2304** is unpredictable and not meaningful. 2305** 2306** See also: 2307** <ul> 2308** <li> the [sqlite3_total_changes()] interface 2309** <li> the [count_changes pragma] 2310** <li> the [changes() SQL function] 2311** <li> the [data_version pragma] 2312** </ul> 2313*/ 2314int sqlite3_changes(sqlite3*); 2315 2316/* 2317** CAPI3REF: Total Number Of Rows Modified 2318** METHOD: sqlite3 2319** 2320** ^This function returns the total number of rows inserted, modified or 2321** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2322** since the database connection was opened, including those executed as 2323** part of trigger programs. ^Executing any other type of SQL statement 2324** does not affect the value returned by sqlite3_total_changes(). 2325** 2326** ^Changes made as part of [foreign key actions] are included in the 2327** count, but those made as part of REPLACE constraint resolution are 2328** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2329** are not counted. 2330** 2331** This the [sqlite3_total_changes(D)] interface only reports the number 2332** of rows that changed due to SQL statement run against database 2333** connection D. Any changes by other database connections are ignored. 2334** To detect changes against a database file from other database 2335** connections use the [PRAGMA data_version] command or the 2336** [SQLITE_FCNTL_DATA_VERSION] [file control]. 2337** 2338** If a separate thread makes changes on the same database connection 2339** while [sqlite3_total_changes()] is running then the value 2340** returned is unpredictable and not meaningful. 2341** 2342** See also: 2343** <ul> 2344** <li> the [sqlite3_changes()] interface 2345** <li> the [count_changes pragma] 2346** <li> the [changes() SQL function] 2347** <li> the [data_version pragma] 2348** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control] 2349** </ul> 2350*/ 2351int sqlite3_total_changes(sqlite3*); 2352 2353/* 2354** CAPI3REF: Interrupt A Long-Running Query 2355** METHOD: sqlite3 2356** 2357** ^This function causes any pending database operation to abort and 2358** return at its earliest opportunity. This routine is typically 2359** called in response to a user action such as pressing "Cancel" 2360** or Ctrl-C where the user wants a long query operation to halt 2361** immediately. 2362** 2363** ^It is safe to call this routine from a thread different from the 2364** thread that is currently running the database operation. But it 2365** is not safe to call this routine with a [database connection] that 2366** is closed or might close before sqlite3_interrupt() returns. 2367** 2368** ^If an SQL operation is very nearly finished at the time when 2369** sqlite3_interrupt() is called, then it might not have an opportunity 2370** to be interrupted and might continue to completion. 2371** 2372** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2373** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2374** that is inside an explicit transaction, then the entire transaction 2375** will be rolled back automatically. 2376** 2377** ^The sqlite3_interrupt(D) call is in effect until all currently running 2378** SQL statements on [database connection] D complete. ^Any new SQL statements 2379** that are started after the sqlite3_interrupt() call and before the 2380** running statements reaches zero are interrupted as if they had been 2381** running prior to the sqlite3_interrupt() call. ^New SQL statements 2382** that are started after the running statement count reaches zero are 2383** not effected by the sqlite3_interrupt(). 2384** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2385** SQL statements is a no-op and has no effect on SQL statements 2386** that are started after the sqlite3_interrupt() call returns. 2387*/ 2388void sqlite3_interrupt(sqlite3*); 2389 2390/* 2391** CAPI3REF: Determine If An SQL Statement Is Complete 2392** 2393** These routines are useful during command-line input to determine if the 2394** currently entered text seems to form a complete SQL statement or 2395** if additional input is needed before sending the text into 2396** SQLite for parsing. ^These routines return 1 if the input string 2397** appears to be a complete SQL statement. ^A statement is judged to be 2398** complete if it ends with a semicolon token and is not a prefix of a 2399** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2400** string literals or quoted identifier names or comments are not 2401** independent tokens (they are part of the token in which they are 2402** embedded) and thus do not count as a statement terminator. ^Whitespace 2403** and comments that follow the final semicolon are ignored. 2404** 2405** ^These routines return 0 if the statement is incomplete. ^If a 2406** memory allocation fails, then SQLITE_NOMEM is returned. 2407** 2408** ^These routines do not parse the SQL statements thus 2409** will not detect syntactically incorrect SQL. 2410** 2411** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2412** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2413** automatically by sqlite3_complete16(). If that initialization fails, 2414** then the return value from sqlite3_complete16() will be non-zero 2415** regardless of whether or not the input SQL is complete.)^ 2416** 2417** The input to [sqlite3_complete()] must be a zero-terminated 2418** UTF-8 string. 2419** 2420** The input to [sqlite3_complete16()] must be a zero-terminated 2421** UTF-16 string in native byte order. 2422*/ 2423int sqlite3_complete(const char *sql); 2424int sqlite3_complete16(const void *sql); 2425 2426/* 2427** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2428** KEYWORDS: {busy-handler callback} {busy handler} 2429** METHOD: sqlite3 2430** 2431** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2432** that might be invoked with argument P whenever 2433** an attempt is made to access a database table associated with 2434** [database connection] D when another thread 2435** or process has the table locked. 2436** The sqlite3_busy_handler() interface is used to implement 2437** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2438** 2439** ^If the busy callback is NULL, then [SQLITE_BUSY] 2440** is returned immediately upon encountering the lock. ^If the busy callback 2441** is not NULL, then the callback might be invoked with two arguments. 2442** 2443** ^The first argument to the busy handler is a copy of the void* pointer which 2444** is the third argument to sqlite3_busy_handler(). ^The second argument to 2445** the busy handler callback is the number of times that the busy handler has 2446** been invoked previously for the same locking event. ^If the 2447** busy callback returns 0, then no additional attempts are made to 2448** access the database and [SQLITE_BUSY] is returned 2449** to the application. 2450** ^If the callback returns non-zero, then another attempt 2451** is made to access the database and the cycle repeats. 2452** 2453** The presence of a busy handler does not guarantee that it will be invoked 2454** when there is lock contention. ^If SQLite determines that invoking the busy 2455** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2456** to the application instead of invoking the 2457** busy handler. 2458** Consider a scenario where one process is holding a read lock that 2459** it is trying to promote to a reserved lock and 2460** a second process is holding a reserved lock that it is trying 2461** to promote to an exclusive lock. The first process cannot proceed 2462** because it is blocked by the second and the second process cannot 2463** proceed because it is blocked by the first. If both processes 2464** invoke the busy handlers, neither will make any progress. Therefore, 2465** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2466** will induce the first process to release its read lock and allow 2467** the second process to proceed. 2468** 2469** ^The default busy callback is NULL. 2470** 2471** ^(There can only be a single busy handler defined for each 2472** [database connection]. Setting a new busy handler clears any 2473** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2474** or evaluating [PRAGMA busy_timeout=N] will change the 2475** busy handler and thus clear any previously set busy handler. 2476** 2477** The busy callback should not take any actions which modify the 2478** database connection that invoked the busy handler. In other words, 2479** the busy handler is not reentrant. Any such actions 2480** result in undefined behavior. 2481** 2482** A busy handler must not close the database connection 2483** or [prepared statement] that invoked the busy handler. 2484*/ 2485int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2486 2487/* 2488** CAPI3REF: Set A Busy Timeout 2489** METHOD: sqlite3 2490** 2491** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2492** for a specified amount of time when a table is locked. ^The handler 2493** will sleep multiple times until at least "ms" milliseconds of sleeping 2494** have accumulated. ^After at least "ms" milliseconds of sleeping, 2495** the handler returns 0 which causes [sqlite3_step()] to return 2496** [SQLITE_BUSY]. 2497** 2498** ^Calling this routine with an argument less than or equal to zero 2499** turns off all busy handlers. 2500** 2501** ^(There can only be a single busy handler for a particular 2502** [database connection] at any given moment. If another busy handler 2503** was defined (using [sqlite3_busy_handler()]) prior to calling 2504** this routine, that other busy handler is cleared.)^ 2505** 2506** See also: [PRAGMA busy_timeout] 2507*/ 2508int sqlite3_busy_timeout(sqlite3*, int ms); 2509 2510/* 2511** CAPI3REF: Convenience Routines For Running Queries 2512** METHOD: sqlite3 2513** 2514** This is a legacy interface that is preserved for backwards compatibility. 2515** Use of this interface is not recommended. 2516** 2517** Definition: A <b>result table</b> is memory data structure created by the 2518** [sqlite3_get_table()] interface. A result table records the 2519** complete query results from one or more queries. 2520** 2521** The table conceptually has a number of rows and columns. But 2522** these numbers are not part of the result table itself. These 2523** numbers are obtained separately. Let N be the number of rows 2524** and M be the number of columns. 2525** 2526** A result table is an array of pointers to zero-terminated UTF-8 strings. 2527** There are (N+1)*M elements in the array. The first M pointers point 2528** to zero-terminated strings that contain the names of the columns. 2529** The remaining entries all point to query results. NULL values result 2530** in NULL pointers. All other values are in their UTF-8 zero-terminated 2531** string representation as returned by [sqlite3_column_text()]. 2532** 2533** A result table might consist of one or more memory allocations. 2534** It is not safe to pass a result table directly to [sqlite3_free()]. 2535** A result table should be deallocated using [sqlite3_free_table()]. 2536** 2537** ^(As an example of the result table format, suppose a query result 2538** is as follows: 2539** 2540** <blockquote><pre> 2541** Name | Age 2542** ----------------------- 2543** Alice | 43 2544** Bob | 28 2545** Cindy | 21 2546** </pre></blockquote> 2547** 2548** There are two column (M==2) and three rows (N==3). Thus the 2549** result table has 8 entries. Suppose the result table is stored 2550** in an array names azResult. Then azResult holds this content: 2551** 2552** <blockquote><pre> 2553** azResult[0] = "Name"; 2554** azResult[1] = "Age"; 2555** azResult[2] = "Alice"; 2556** azResult[3] = "43"; 2557** azResult[4] = "Bob"; 2558** azResult[5] = "28"; 2559** azResult[6] = "Cindy"; 2560** azResult[7] = "21"; 2561** </pre></blockquote>)^ 2562** 2563** ^The sqlite3_get_table() function evaluates one or more 2564** semicolon-separated SQL statements in the zero-terminated UTF-8 2565** string of its 2nd parameter and returns a result table to the 2566** pointer given in its 3rd parameter. 2567** 2568** After the application has finished with the result from sqlite3_get_table(), 2569** it must pass the result table pointer to sqlite3_free_table() in order to 2570** release the memory that was malloced. Because of the way the 2571** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2572** function must not try to call [sqlite3_free()] directly. Only 2573** [sqlite3_free_table()] is able to release the memory properly and safely. 2574** 2575** The sqlite3_get_table() interface is implemented as a wrapper around 2576** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2577** to any internal data structures of SQLite. It uses only the public 2578** interface defined here. As a consequence, errors that occur in the 2579** wrapper layer outside of the internal [sqlite3_exec()] call are not 2580** reflected in subsequent calls to [sqlite3_errcode()] or 2581** [sqlite3_errmsg()]. 2582*/ 2583int sqlite3_get_table( 2584 sqlite3 *db, /* An open database */ 2585 const char *zSql, /* SQL to be evaluated */ 2586 char ***pazResult, /* Results of the query */ 2587 int *pnRow, /* Number of result rows written here */ 2588 int *pnColumn, /* Number of result columns written here */ 2589 char **pzErrmsg /* Error msg written here */ 2590); 2591void sqlite3_free_table(char **result); 2592 2593/* 2594** CAPI3REF: Formatted String Printing Functions 2595** 2596** These routines are work-alikes of the "printf()" family of functions 2597** from the standard C library. 2598** These routines understand most of the common formatting options from 2599** the standard library printf() 2600** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]). 2601** See the [built-in printf()] documentation for details. 2602** 2603** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2604** results into memory obtained from [sqlite3_malloc64()]. 2605** The strings returned by these two routines should be 2606** released by [sqlite3_free()]. ^Both routines return a 2607** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough 2608** memory to hold the resulting string. 2609** 2610** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2611** the standard C library. The result is written into the 2612** buffer supplied as the second parameter whose size is given by 2613** the first parameter. Note that the order of the 2614** first two parameters is reversed from snprintf().)^ This is an 2615** historical accident that cannot be fixed without breaking 2616** backwards compatibility. ^(Note also that sqlite3_snprintf() 2617** returns a pointer to its buffer instead of the number of 2618** characters actually written into the buffer.)^ We admit that 2619** the number of characters written would be a more useful return 2620** value but we cannot change the implementation of sqlite3_snprintf() 2621** now without breaking compatibility. 2622** 2623** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2624** guarantees that the buffer is always zero-terminated. ^The first 2625** parameter "n" is the total size of the buffer, including space for 2626** the zero terminator. So the longest string that can be completely 2627** written will be n-1 characters. 2628** 2629** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2630** 2631** See also: [built-in printf()], [printf() SQL function] 2632*/ 2633char *sqlite3_mprintf(const char*,...); 2634char *sqlite3_vmprintf(const char*, va_list); 2635char *sqlite3_snprintf(int,char*,const char*, ...); 2636char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2637 2638/* 2639** CAPI3REF: Memory Allocation Subsystem 2640** 2641** The SQLite core uses these three routines for all of its own 2642** internal memory allocation needs. "Core" in the previous sentence 2643** does not include operating-system specific VFS implementation. The 2644** Windows VFS uses native malloc() and free() for some operations. 2645** 2646** ^The sqlite3_malloc() routine returns a pointer to a block 2647** of memory at least N bytes in length, where N is the parameter. 2648** ^If sqlite3_malloc() is unable to obtain sufficient free 2649** memory, it returns a NULL pointer. ^If the parameter N to 2650** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2651** a NULL pointer. 2652** 2653** ^The sqlite3_malloc64(N) routine works just like 2654** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2655** of a signed 32-bit integer. 2656** 2657** ^Calling sqlite3_free() with a pointer previously returned 2658** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2659** that it might be reused. ^The sqlite3_free() routine is 2660** a no-op if is called with a NULL pointer. Passing a NULL pointer 2661** to sqlite3_free() is harmless. After being freed, memory 2662** should neither be read nor written. Even reading previously freed 2663** memory might result in a segmentation fault or other severe error. 2664** Memory corruption, a segmentation fault, or other severe error 2665** might result if sqlite3_free() is called with a non-NULL pointer that 2666** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2667** 2668** ^The sqlite3_realloc(X,N) interface attempts to resize a 2669** prior memory allocation X to be at least N bytes. 2670** ^If the X parameter to sqlite3_realloc(X,N) 2671** is a NULL pointer then its behavior is identical to calling 2672** sqlite3_malloc(N). 2673** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2674** negative then the behavior is exactly the same as calling 2675** sqlite3_free(X). 2676** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2677** of at least N bytes in size or NULL if insufficient memory is available. 2678** ^If M is the size of the prior allocation, then min(N,M) bytes 2679** of the prior allocation are copied into the beginning of buffer returned 2680** by sqlite3_realloc(X,N) and the prior allocation is freed. 2681** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2682** prior allocation is not freed. 2683** 2684** ^The sqlite3_realloc64(X,N) interfaces works the same as 2685** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2686** of a 32-bit signed integer. 2687** 2688** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2689** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2690** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2691** ^The value returned by sqlite3_msize(X) might be larger than the number 2692** of bytes requested when X was allocated. ^If X is a NULL pointer then 2693** sqlite3_msize(X) returns zero. If X points to something that is not 2694** the beginning of memory allocation, or if it points to a formerly 2695** valid memory allocation that has now been freed, then the behavior 2696** of sqlite3_msize(X) is undefined and possibly harmful. 2697** 2698** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2699** sqlite3_malloc64(), and sqlite3_realloc64() 2700** is always aligned to at least an 8 byte boundary, or to a 2701** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2702** option is used. 2703** 2704** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2705** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2706** implementation of these routines to be omitted. That capability 2707** is no longer provided. Only built-in memory allocators can be used. 2708** 2709** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2710** the system malloc() and free() directly when converting 2711** filenames between the UTF-8 encoding used by SQLite 2712** and whatever filename encoding is used by the particular Windows 2713** installation. Memory allocation errors were detected, but 2714** they were reported back as [SQLITE_CANTOPEN] or 2715** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2716** 2717** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2718** must be either NULL or else pointers obtained from a prior 2719** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2720** not yet been released. 2721** 2722** The application must not read or write any part of 2723** a block of memory after it has been released using 2724** [sqlite3_free()] or [sqlite3_realloc()]. 2725*/ 2726void *sqlite3_malloc(int); 2727void *sqlite3_malloc64(sqlite3_uint64); 2728void *sqlite3_realloc(void*, int); 2729void *sqlite3_realloc64(void*, sqlite3_uint64); 2730void sqlite3_free(void*); 2731sqlite3_uint64 sqlite3_msize(void*); 2732 2733/* 2734** CAPI3REF: Memory Allocator Statistics 2735** 2736** SQLite provides these two interfaces for reporting on the status 2737** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2738** routines, which form the built-in memory allocation subsystem. 2739** 2740** ^The [sqlite3_memory_used()] routine returns the number of bytes 2741** of memory currently outstanding (malloced but not freed). 2742** ^The [sqlite3_memory_highwater()] routine returns the maximum 2743** value of [sqlite3_memory_used()] since the high-water mark 2744** was last reset. ^The values returned by [sqlite3_memory_used()] and 2745** [sqlite3_memory_highwater()] include any overhead 2746** added by SQLite in its implementation of [sqlite3_malloc()], 2747** but not overhead added by the any underlying system library 2748** routines that [sqlite3_malloc()] may call. 2749** 2750** ^The memory high-water mark is reset to the current value of 2751** [sqlite3_memory_used()] if and only if the parameter to 2752** [sqlite3_memory_highwater()] is true. ^The value returned 2753** by [sqlite3_memory_highwater(1)] is the high-water mark 2754** prior to the reset. 2755*/ 2756sqlite3_int64 sqlite3_memory_used(void); 2757sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2758 2759/* 2760** CAPI3REF: Pseudo-Random Number Generator 2761** 2762** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2763** select random [ROWID | ROWIDs] when inserting new records into a table that 2764** already uses the largest possible [ROWID]. The PRNG is also used for 2765** the build-in random() and randomblob() SQL functions. This interface allows 2766** applications to access the same PRNG for other purposes. 2767** 2768** ^A call to this routine stores N bytes of randomness into buffer P. 2769** ^The P parameter can be a NULL pointer. 2770** 2771** ^If this routine has not been previously called or if the previous 2772** call had N less than one or a NULL pointer for P, then the PRNG is 2773** seeded using randomness obtained from the xRandomness method of 2774** the default [sqlite3_vfs] object. 2775** ^If the previous call to this routine had an N of 1 or more and a 2776** non-NULL P then the pseudo-randomness is generated 2777** internally and without recourse to the [sqlite3_vfs] xRandomness 2778** method. 2779*/ 2780void sqlite3_randomness(int N, void *P); 2781 2782/* 2783** CAPI3REF: Compile-Time Authorization Callbacks 2784** METHOD: sqlite3 2785** KEYWORDS: {authorizer callback} 2786** 2787** ^This routine registers an authorizer callback with a particular 2788** [database connection], supplied in the first argument. 2789** ^The authorizer callback is invoked as SQL statements are being compiled 2790** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2791** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2792** and [sqlite3_prepare16_v3()]. ^At various 2793** points during the compilation process, as logic is being created 2794** to perform various actions, the authorizer callback is invoked to 2795** see if those actions are allowed. ^The authorizer callback should 2796** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2797** specific action but allow the SQL statement to continue to be 2798** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2799** rejected with an error. ^If the authorizer callback returns 2800** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2801** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2802** the authorizer will fail with an error message. 2803** 2804** When the callback returns [SQLITE_OK], that means the operation 2805** requested is ok. ^When the callback returns [SQLITE_DENY], the 2806** [sqlite3_prepare_v2()] or equivalent call that triggered the 2807** authorizer will fail with an error message explaining that 2808** access is denied. 2809** 2810** ^The first parameter to the authorizer callback is a copy of the third 2811** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2812** to the callback is an integer [SQLITE_COPY | action code] that specifies 2813** the particular action to be authorized. ^The third through sixth parameters 2814** to the callback are either NULL pointers or zero-terminated strings 2815** that contain additional details about the action to be authorized. 2816** Applications must always be prepared to encounter a NULL pointer in any 2817** of the third through the sixth parameters of the authorization callback. 2818** 2819** ^If the action code is [SQLITE_READ] 2820** and the callback returns [SQLITE_IGNORE] then the 2821** [prepared statement] statement is constructed to substitute 2822** a NULL value in place of the table column that would have 2823** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2824** return can be used to deny an untrusted user access to individual 2825** columns of a table. 2826** ^When a table is referenced by a [SELECT] but no column values are 2827** extracted from that table (for example in a query like 2828** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2829** is invoked once for that table with a column name that is an empty string. 2830** ^If the action code is [SQLITE_DELETE] and the callback returns 2831** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2832** [truncate optimization] is disabled and all rows are deleted individually. 2833** 2834** An authorizer is used when [sqlite3_prepare | preparing] 2835** SQL statements from an untrusted source, to ensure that the SQL statements 2836** do not try to access data they are not allowed to see, or that they do not 2837** try to execute malicious statements that damage the database. For 2838** example, an application may allow a user to enter arbitrary 2839** SQL queries for evaluation by a database. But the application does 2840** not want the user to be able to make arbitrary changes to the 2841** database. An authorizer could then be put in place while the 2842** user-entered SQL is being [sqlite3_prepare | prepared] that 2843** disallows everything except [SELECT] statements. 2844** 2845** Applications that need to process SQL from untrusted sources 2846** might also consider lowering resource limits using [sqlite3_limit()] 2847** and limiting database size using the [max_page_count] [PRAGMA] 2848** in addition to using an authorizer. 2849** 2850** ^(Only a single authorizer can be in place on a database connection 2851** at a time. Each call to sqlite3_set_authorizer overrides the 2852** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2853** The authorizer is disabled by default. 2854** 2855** The authorizer callback must not do anything that will modify 2856** the database connection that invoked the authorizer callback. 2857** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2858** database connections for the meaning of "modify" in this paragraph. 2859** 2860** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2861** statement might be re-prepared during [sqlite3_step()] due to a 2862** schema change. Hence, the application should ensure that the 2863** correct authorizer callback remains in place during the [sqlite3_step()]. 2864** 2865** ^Note that the authorizer callback is invoked only during 2866** [sqlite3_prepare()] or its variants. Authorization is not 2867** performed during statement evaluation in [sqlite3_step()], unless 2868** as stated in the previous paragraph, sqlite3_step() invokes 2869** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2870*/ 2871int sqlite3_set_authorizer( 2872 sqlite3*, 2873 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2874 void *pUserData 2875); 2876 2877/* 2878** CAPI3REF: Authorizer Return Codes 2879** 2880** The [sqlite3_set_authorizer | authorizer callback function] must 2881** return either [SQLITE_OK] or one of these two constants in order 2882** to signal SQLite whether or not the action is permitted. See the 2883** [sqlite3_set_authorizer | authorizer documentation] for additional 2884** information. 2885** 2886** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2887** returned from the [sqlite3_vtab_on_conflict()] interface. 2888*/ 2889#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2890#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2891 2892/* 2893** CAPI3REF: Authorizer Action Codes 2894** 2895** The [sqlite3_set_authorizer()] interface registers a callback function 2896** that is invoked to authorize certain SQL statement actions. The 2897** second parameter to the callback is an integer code that specifies 2898** what action is being authorized. These are the integer action codes that 2899** the authorizer callback may be passed. 2900** 2901** These action code values signify what kind of operation is to be 2902** authorized. The 3rd and 4th parameters to the authorization 2903** callback function will be parameters or NULL depending on which of these 2904** codes is used as the second parameter. ^(The 5th parameter to the 2905** authorizer callback is the name of the database ("main", "temp", 2906** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2907** is the name of the inner-most trigger or view that is responsible for 2908** the access attempt or NULL if this access attempt is directly from 2909** top-level SQL code. 2910*/ 2911/******************************************* 3rd ************ 4th ***********/ 2912#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2913#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2914#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2915#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2916#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2917#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2918#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2919#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2920#define SQLITE_DELETE 9 /* Table Name NULL */ 2921#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2922#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2923#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2924#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2925#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2926#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2927#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2928#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2929#define SQLITE_INSERT 18 /* Table Name NULL */ 2930#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2931#define SQLITE_READ 20 /* Table Name Column Name */ 2932#define SQLITE_SELECT 21 /* NULL NULL */ 2933#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2934#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2935#define SQLITE_ATTACH 24 /* Filename NULL */ 2936#define SQLITE_DETACH 25 /* Database Name NULL */ 2937#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2938#define SQLITE_REINDEX 27 /* Index Name NULL */ 2939#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2940#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2941#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2942#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2943#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2944#define SQLITE_COPY 0 /* No longer used */ 2945#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2946 2947/* 2948** CAPI3REF: Tracing And Profiling Functions 2949** METHOD: sqlite3 2950** 2951** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 2952** instead of the routines described here. 2953** 2954** These routines register callback functions that can be used for 2955** tracing and profiling the execution of SQL statements. 2956** 2957** ^The callback function registered by sqlite3_trace() is invoked at 2958** various times when an SQL statement is being run by [sqlite3_step()]. 2959** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2960** SQL statement text as the statement first begins executing. 2961** ^(Additional sqlite3_trace() callbacks might occur 2962** as each triggered subprogram is entered. The callbacks for triggers 2963** contain a UTF-8 SQL comment that identifies the trigger.)^ 2964** 2965** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2966** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2967** 2968** ^The callback function registered by sqlite3_profile() is invoked 2969** as each SQL statement finishes. ^The profile callback contains 2970** the original statement text and an estimate of wall-clock time 2971** of how long that statement took to run. ^The profile callback 2972** time is in units of nanoseconds, however the current implementation 2973** is only capable of millisecond resolution so the six least significant 2974** digits in the time are meaningless. Future versions of SQLite 2975** might provide greater resolution on the profiler callback. The 2976** sqlite3_profile() function is considered experimental and is 2977** subject to change in future versions of SQLite. 2978*/ 2979SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 2980 void(*xTrace)(void*,const char*), void*); 2981SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 2982 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2983 2984/* 2985** CAPI3REF: SQL Trace Event Codes 2986** KEYWORDS: SQLITE_TRACE 2987** 2988** These constants identify classes of events that can be monitored 2989** using the [sqlite3_trace_v2()] tracing logic. The M argument 2990** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of 2991** the following constants. ^The first argument to the trace callback 2992** is one of the following constants. 2993** 2994** New tracing constants may be added in future releases. 2995** 2996** ^A trace callback has four arguments: xCallback(T,C,P,X). 2997** ^The T argument is one of the integer type codes above. 2998** ^The C argument is a copy of the context pointer passed in as the 2999** fourth argument to [sqlite3_trace_v2()]. 3000** The P and X arguments are pointers whose meanings depend on T. 3001** 3002** <dl> 3003** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 3004** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 3005** first begins running and possibly at other times during the 3006** execution of the prepared statement, such as at the start of each 3007** trigger subprogram. ^The P argument is a pointer to the 3008** [prepared statement]. ^The X argument is a pointer to a string which 3009** is the unexpanded SQL text of the prepared statement or an SQL comment 3010** that indicates the invocation of a trigger. ^The callback can compute 3011** the same text that would have been returned by the legacy [sqlite3_trace()] 3012** interface by using the X argument when X begins with "--" and invoking 3013** [sqlite3_expanded_sql(P)] otherwise. 3014** 3015** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 3016** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 3017** information as is provided by the [sqlite3_profile()] callback. 3018** ^The P argument is a pointer to the [prepared statement] and the 3019** X argument points to a 64-bit integer which is the estimated of 3020** the number of nanosecond that the prepared statement took to run. 3021** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 3022** 3023** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 3024** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 3025** statement generates a single row of result. 3026** ^The P argument is a pointer to the [prepared statement] and the 3027** X argument is unused. 3028** 3029** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 3030** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 3031** connection closes. 3032** ^The P argument is a pointer to the [database connection] object 3033** and the X argument is unused. 3034** </dl> 3035*/ 3036#define SQLITE_TRACE_STMT 0x01 3037#define SQLITE_TRACE_PROFILE 0x02 3038#define SQLITE_TRACE_ROW 0x04 3039#define SQLITE_TRACE_CLOSE 0x08 3040 3041/* 3042** CAPI3REF: SQL Trace Hook 3043** METHOD: sqlite3 3044** 3045** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 3046** function X against [database connection] D, using property mask M 3047** and context pointer P. ^If the X callback is 3048** NULL or if the M mask is zero, then tracing is disabled. The 3049** M argument should be the bitwise OR-ed combination of 3050** zero or more [SQLITE_TRACE] constants. 3051** 3052** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 3053** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 3054** 3055** ^The X callback is invoked whenever any of the events identified by 3056** mask M occur. ^The integer return value from the callback is currently 3057** ignored, though this may change in future releases. Callback 3058** implementations should return zero to ensure future compatibility. 3059** 3060** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 3061** ^The T argument is one of the [SQLITE_TRACE] 3062** constants to indicate why the callback was invoked. 3063** ^The C argument is a copy of the context pointer. 3064** The P and X arguments are pointers whose meanings depend on T. 3065** 3066** The sqlite3_trace_v2() interface is intended to replace the legacy 3067** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 3068** are deprecated. 3069*/ 3070int sqlite3_trace_v2( 3071 sqlite3*, 3072 unsigned uMask, 3073 int(*xCallback)(unsigned,void*,void*,void*), 3074 void *pCtx 3075); 3076 3077/* 3078** CAPI3REF: Query Progress Callbacks 3079** METHOD: sqlite3 3080** 3081** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 3082** function X to be invoked periodically during long running calls to 3083** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 3084** database connection D. An example use for this 3085** interface is to keep a GUI updated during a large query. 3086** 3087** ^The parameter P is passed through as the only parameter to the 3088** callback function X. ^The parameter N is the approximate number of 3089** [virtual machine instructions] that are evaluated between successive 3090** invocations of the callback X. ^If N is less than one then the progress 3091** handler is disabled. 3092** 3093** ^Only a single progress handler may be defined at one time per 3094** [database connection]; setting a new progress handler cancels the 3095** old one. ^Setting parameter X to NULL disables the progress handler. 3096** ^The progress handler is also disabled by setting N to a value less 3097** than 1. 3098** 3099** ^If the progress callback returns non-zero, the operation is 3100** interrupted. This feature can be used to implement a 3101** "Cancel" button on a GUI progress dialog box. 3102** 3103** The progress handler callback must not do anything that will modify 3104** the database connection that invoked the progress handler. 3105** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3106** database connections for the meaning of "modify" in this paragraph. 3107** 3108*/ 3109void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3110 3111/* 3112** CAPI3REF: Opening A New Database Connection 3113** CONSTRUCTOR: sqlite3 3114** 3115** ^These routines open an SQLite database file as specified by the 3116** filename argument. ^The filename argument is interpreted as UTF-8 for 3117** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3118** order for sqlite3_open16(). ^(A [database connection] handle is usually 3119** returned in *ppDb, even if an error occurs. The only exception is that 3120** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3121** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3122** object.)^ ^(If the database is opened (and/or created) successfully, then 3123** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3124** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3125** an English language description of the error following a failure of any 3126** of the sqlite3_open() routines. 3127** 3128** ^The default encoding will be UTF-8 for databases created using 3129** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3130** created using sqlite3_open16() will be UTF-16 in the native byte order. 3131** 3132** Whether or not an error occurs when it is opened, resources 3133** associated with the [database connection] handle should be released by 3134** passing it to [sqlite3_close()] when it is no longer required. 3135** 3136** The sqlite3_open_v2() interface works like sqlite3_open() 3137** except that it accepts two additional parameters for additional control 3138** over the new database connection. ^(The flags parameter to 3139** sqlite3_open_v2() can take one of 3140** the following three values, optionally combined with the 3141** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 3142** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 3143** 3144** <dl> 3145** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3146** <dd>The database is opened in read-only mode. If the database does not 3147** already exist, an error is returned.</dd>)^ 3148** 3149** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3150** <dd>The database is opened for reading and writing if possible, or reading 3151** only if the file is write protected by the operating system. In either 3152** case the database must already exist, otherwise an error is returned.</dd>)^ 3153** 3154** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3155** <dd>The database is opened for reading and writing, and is created if 3156** it does not already exist. This is the behavior that is always used for 3157** sqlite3_open() and sqlite3_open16().</dd>)^ 3158** </dl> 3159** 3160** If the 3rd parameter to sqlite3_open_v2() is not one of the 3161** combinations shown above optionally combined with other 3162** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3163** then the behavior is undefined. 3164** 3165** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 3166** opens in the multi-thread [threading mode] as long as the single-thread 3167** mode has not been set at compile-time or start-time. ^If the 3168** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 3169** in the serialized [threading mode] unless single-thread was 3170** previously selected at compile-time or start-time. 3171** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 3172** eligible to use [shared cache mode], regardless of whether or not shared 3173** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 3174** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 3175** participate in [shared cache mode] even if it is enabled. 3176** 3177** ^The fourth parameter to sqlite3_open_v2() is the name of the 3178** [sqlite3_vfs] object that defines the operating system interface that 3179** the new database connection should use. ^If the fourth parameter is 3180** a NULL pointer then the default [sqlite3_vfs] object is used. 3181** 3182** ^If the filename is ":memory:", then a private, temporary in-memory database 3183** is created for the connection. ^This in-memory database will vanish when 3184** the database connection is closed. Future versions of SQLite might 3185** make use of additional special filenames that begin with the ":" character. 3186** It is recommended that when a database filename actually does begin with 3187** a ":" character you should prefix the filename with a pathname such as 3188** "./" to avoid ambiguity. 3189** 3190** ^If the filename is an empty string, then a private, temporary 3191** on-disk database will be created. ^This private database will be 3192** automatically deleted as soon as the database connection is closed. 3193** 3194** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3195** 3196** ^If [URI filename] interpretation is enabled, and the filename argument 3197** begins with "file:", then the filename is interpreted as a URI. ^URI 3198** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3199** set in the third argument to sqlite3_open_v2(), or if it has 3200** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3201** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3202** URI filename interpretation is turned off 3203** by default, but future releases of SQLite might enable URI filename 3204** interpretation by default. See "[URI filenames]" for additional 3205** information. 3206** 3207** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3208** authority, then it must be either an empty string or the string 3209** "localhost". ^If the authority is not an empty string or "localhost", an 3210** error is returned to the caller. ^The fragment component of a URI, if 3211** present, is ignored. 3212** 3213** ^SQLite uses the path component of the URI as the name of the disk file 3214** which contains the database. ^If the path begins with a '/' character, 3215** then it is interpreted as an absolute path. ^If the path does not begin 3216** with a '/' (meaning that the authority section is omitted from the URI) 3217** then the path is interpreted as a relative path. 3218** ^(On windows, the first component of an absolute path 3219** is a drive specification (e.g. "C:").)^ 3220** 3221** [[core URI query parameters]] 3222** The query component of a URI may contain parameters that are interpreted 3223** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3224** SQLite and its built-in [VFSes] interpret the 3225** following query parameters: 3226** 3227** <ul> 3228** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3229** a VFS object that provides the operating system interface that should 3230** be used to access the database file on disk. ^If this option is set to 3231** an empty string the default VFS object is used. ^Specifying an unknown 3232** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3233** present, then the VFS specified by the option takes precedence over 3234** the value passed as the fourth parameter to sqlite3_open_v2(). 3235** 3236** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3237** "rwc", or "memory". Attempting to set it to any other value is 3238** an error)^. 3239** ^If "ro" is specified, then the database is opened for read-only 3240** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3241** third argument to sqlite3_open_v2(). ^If the mode option is set to 3242** "rw", then the database is opened for read-write (but not create) 3243** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3244** been set. ^Value "rwc" is equivalent to setting both 3245** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3246** set to "memory" then a pure [in-memory database] that never reads 3247** or writes from disk is used. ^It is an error to specify a value for 3248** the mode parameter that is less restrictive than that specified by 3249** the flags passed in the third parameter to sqlite3_open_v2(). 3250** 3251** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3252** "private". ^Setting it to "shared" is equivalent to setting the 3253** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3254** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3255** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3256** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3257** a URI filename, its value overrides any behavior requested by setting 3258** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3259** 3260** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3261** [powersafe overwrite] property does or does not apply to the 3262** storage media on which the database file resides. 3263** 3264** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3265** which if set disables file locking in rollback journal modes. This 3266** is useful for accessing a database on a filesystem that does not 3267** support locking. Caution: Database corruption might result if two 3268** or more processes write to the same database and any one of those 3269** processes uses nolock=1. 3270** 3271** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3272** parameter that indicates that the database file is stored on 3273** read-only media. ^When immutable is set, SQLite assumes that the 3274** database file cannot be changed, even by a process with higher 3275** privilege, and so the database is opened read-only and all locking 3276** and change detection is disabled. Caution: Setting the immutable 3277** property on a database file that does in fact change can result 3278** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3279** See also: [SQLITE_IOCAP_IMMUTABLE]. 3280** 3281** </ul> 3282** 3283** ^Specifying an unknown parameter in the query component of a URI is not an 3284** error. Future versions of SQLite might understand additional query 3285** parameters. See "[query parameters with special meaning to SQLite]" for 3286** additional information. 3287** 3288** [[URI filename examples]] <h3>URI filename examples</h3> 3289** 3290** <table border="1" align=center cellpadding=5> 3291** <tr><th> URI filenames <th> Results 3292** <tr><td> file:data.db <td> 3293** Open the file "data.db" in the current directory. 3294** <tr><td> file:/home/fred/data.db<br> 3295** file:///home/fred/data.db <br> 3296** file://localhost/home/fred/data.db <br> <td> 3297** Open the database file "/home/fred/data.db". 3298** <tr><td> file://darkstar/home/fred/data.db <td> 3299** An error. "darkstar" is not a recognized authority. 3300** <tr><td style="white-space:nowrap"> 3301** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3302** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3303** C:. Note that the %20 escaping in this example is not strictly 3304** necessary - space characters can be used literally 3305** in URI filenames. 3306** <tr><td> file:data.db?mode=ro&cache=private <td> 3307** Open file "data.db" in the current directory for read-only access. 3308** Regardless of whether or not shared-cache mode is enabled by 3309** default, use a private cache. 3310** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3311** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3312** that uses dot-files in place of posix advisory locking. 3313** <tr><td> file:data.db?mode=readonly <td> 3314** An error. "readonly" is not a valid option for the "mode" parameter. 3315** </table> 3316** 3317** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3318** query components of a URI. A hexadecimal escape sequence consists of a 3319** percent sign - "%" - followed by exactly two hexadecimal digits 3320** specifying an octet value. ^Before the path or query components of a 3321** URI filename are interpreted, they are encoded using UTF-8 and all 3322** hexadecimal escape sequences replaced by a single byte containing the 3323** corresponding octet. If this process generates an invalid UTF-8 encoding, 3324** the results are undefined. 3325** 3326** <b>Note to Windows users:</b> The encoding used for the filename argument 3327** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3328** codepage is currently defined. Filenames containing international 3329** characters must be converted to UTF-8 prior to passing them into 3330** sqlite3_open() or sqlite3_open_v2(). 3331** 3332** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3333** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3334** features that require the use of temporary files may fail. 3335** 3336** See also: [sqlite3_temp_directory] 3337*/ 3338int sqlite3_open( 3339 const char *filename, /* Database filename (UTF-8) */ 3340 sqlite3 **ppDb /* OUT: SQLite db handle */ 3341); 3342int sqlite3_open16( 3343 const void *filename, /* Database filename (UTF-16) */ 3344 sqlite3 **ppDb /* OUT: SQLite db handle */ 3345); 3346int sqlite3_open_v2( 3347 const char *filename, /* Database filename (UTF-8) */ 3348 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3349 int flags, /* Flags */ 3350 const char *zVfs /* Name of VFS module to use */ 3351); 3352 3353/* 3354** CAPI3REF: Obtain Values For URI Parameters 3355** 3356** These are utility routines, useful to VFS implementations, that check 3357** to see if a database file was a URI that contained a specific query 3358** parameter, and if so obtains the value of that query parameter. 3359** 3360** If F is the database filename pointer passed into the xOpen() method of 3361** a VFS implementation when the flags parameter to xOpen() has one or 3362** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3363** P is the name of the query parameter, then 3364** sqlite3_uri_parameter(F,P) returns the value of the P 3365** parameter if it exists or a NULL pointer if P does not appear as a 3366** query parameter on F. If P is a query parameter of F 3367** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3368** a pointer to an empty string. 3369** 3370** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3371** parameter and returns true (1) or false (0) according to the value 3372** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3373** value of query parameter P is one of "yes", "true", or "on" in any 3374** case or if the value begins with a non-zero number. The 3375** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3376** query parameter P is one of "no", "false", or "off" in any case or 3377** if the value begins with a numeric zero. If P is not a query 3378** parameter on F or if the value of P is does not match any of the 3379** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3380** 3381** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3382** 64-bit signed integer and returns that integer, or D if P does not 3383** exist. If the value of P is something other than an integer, then 3384** zero is returned. 3385** 3386** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3387** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3388** is not a database file pathname pointer that SQLite passed into the xOpen 3389** VFS method, then the behavior of this routine is undefined and probably 3390** undesirable. 3391*/ 3392const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3393int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3394sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3395 3396 3397/* 3398** CAPI3REF: Error Codes And Messages 3399** METHOD: sqlite3 3400** 3401** ^If the most recent sqlite3_* API call associated with 3402** [database connection] D failed, then the sqlite3_errcode(D) interface 3403** returns the numeric [result code] or [extended result code] for that 3404** API call. 3405** ^The sqlite3_extended_errcode() 3406** interface is the same except that it always returns the 3407** [extended result code] even when extended result codes are 3408** disabled. 3409** 3410** The values returned by sqlite3_errcode() and/or 3411** sqlite3_extended_errcode() might change with each API call. 3412** Except, there are some interfaces that are guaranteed to never 3413** change the value of the error code. The error-code preserving 3414** interfaces are: 3415** 3416** <ul> 3417** <li> sqlite3_errcode() 3418** <li> sqlite3_extended_errcode() 3419** <li> sqlite3_errmsg() 3420** <li> sqlite3_errmsg16() 3421** </ul> 3422** 3423** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3424** text that describes the error, as either UTF-8 or UTF-16 respectively. 3425** ^(Memory to hold the error message string is managed internally. 3426** The application does not need to worry about freeing the result. 3427** However, the error string might be overwritten or deallocated by 3428** subsequent calls to other SQLite interface functions.)^ 3429** 3430** ^The sqlite3_errstr() interface returns the English-language text 3431** that describes the [result code], as UTF-8. 3432** ^(Memory to hold the error message string is managed internally 3433** and must not be freed by the application)^. 3434** 3435** When the serialized [threading mode] is in use, it might be the 3436** case that a second error occurs on a separate thread in between 3437** the time of the first error and the call to these interfaces. 3438** When that happens, the second error will be reported since these 3439** interfaces always report the most recent result. To avoid 3440** this, each thread can obtain exclusive use of the [database connection] D 3441** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3442** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3443** all calls to the interfaces listed here are completed. 3444** 3445** If an interface fails with SQLITE_MISUSE, that means the interface 3446** was invoked incorrectly by the application. In that case, the 3447** error code and message may or may not be set. 3448*/ 3449int sqlite3_errcode(sqlite3 *db); 3450int sqlite3_extended_errcode(sqlite3 *db); 3451const char *sqlite3_errmsg(sqlite3*); 3452const void *sqlite3_errmsg16(sqlite3*); 3453const char *sqlite3_errstr(int); 3454 3455/* 3456** CAPI3REF: Prepared Statement Object 3457** KEYWORDS: {prepared statement} {prepared statements} 3458** 3459** An instance of this object represents a single SQL statement that 3460** has been compiled into binary form and is ready to be evaluated. 3461** 3462** Think of each SQL statement as a separate computer program. The 3463** original SQL text is source code. A prepared statement object 3464** is the compiled object code. All SQL must be converted into a 3465** prepared statement before it can be run. 3466** 3467** The life-cycle of a prepared statement object usually goes like this: 3468** 3469** <ol> 3470** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3471** <li> Bind values to [parameters] using the sqlite3_bind_*() 3472** interfaces. 3473** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3474** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3475** to step 2. Do this zero or more times. 3476** <li> Destroy the object using [sqlite3_finalize()]. 3477** </ol> 3478*/ 3479typedef struct sqlite3_stmt sqlite3_stmt; 3480 3481/* 3482** CAPI3REF: Run-time Limits 3483** METHOD: sqlite3 3484** 3485** ^(This interface allows the size of various constructs to be limited 3486** on a connection by connection basis. The first parameter is the 3487** [database connection] whose limit is to be set or queried. The 3488** second parameter is one of the [limit categories] that define a 3489** class of constructs to be size limited. The third parameter is the 3490** new limit for that construct.)^ 3491** 3492** ^If the new limit is a negative number, the limit is unchanged. 3493** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3494** [limits | hard upper bound] 3495** set at compile-time by a C preprocessor macro called 3496** [limits | SQLITE_MAX_<i>NAME</i>]. 3497** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3498** ^Attempts to increase a limit above its hard upper bound are 3499** silently truncated to the hard upper bound. 3500** 3501** ^Regardless of whether or not the limit was changed, the 3502** [sqlite3_limit()] interface returns the prior value of the limit. 3503** ^Hence, to find the current value of a limit without changing it, 3504** simply invoke this interface with the third parameter set to -1. 3505** 3506** Run-time limits are intended for use in applications that manage 3507** both their own internal database and also databases that are controlled 3508** by untrusted external sources. An example application might be a 3509** web browser that has its own databases for storing history and 3510** separate databases controlled by JavaScript applications downloaded 3511** off the Internet. The internal databases can be given the 3512** large, default limits. Databases managed by external sources can 3513** be given much smaller limits designed to prevent a denial of service 3514** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3515** interface to further control untrusted SQL. The size of the database 3516** created by an untrusted script can be contained using the 3517** [max_page_count] [PRAGMA]. 3518** 3519** New run-time limit categories may be added in future releases. 3520*/ 3521int sqlite3_limit(sqlite3*, int id, int newVal); 3522 3523/* 3524** CAPI3REF: Run-Time Limit Categories 3525** KEYWORDS: {limit category} {*limit categories} 3526** 3527** These constants define various performance limits 3528** that can be lowered at run-time using [sqlite3_limit()]. 3529** The synopsis of the meanings of the various limits is shown below. 3530** Additional information is available at [limits | Limits in SQLite]. 3531** 3532** <dl> 3533** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3534** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3535** 3536** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3537** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3538** 3539** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3540** <dd>The maximum number of columns in a table definition or in the 3541** result set of a [SELECT] or the maximum number of columns in an index 3542** or in an ORDER BY or GROUP BY clause.</dd>)^ 3543** 3544** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3545** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3546** 3547** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3548** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3549** 3550** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3551** <dd>The maximum number of instructions in a virtual machine program 3552** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3553** the equivalent tries to allocate space for more than this many opcodes 3554** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3555** 3556** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3557** <dd>The maximum number of arguments on a function.</dd>)^ 3558** 3559** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3560** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3561** 3562** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3563** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3564** <dd>The maximum length of the pattern argument to the [LIKE] or 3565** [GLOB] operators.</dd>)^ 3566** 3567** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3568** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3569** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3570** 3571** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3572** <dd>The maximum depth of recursion for triggers.</dd>)^ 3573** 3574** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3575** <dd>The maximum number of auxiliary worker threads that a single 3576** [prepared statement] may start.</dd>)^ 3577** </dl> 3578*/ 3579#define SQLITE_LIMIT_LENGTH 0 3580#define SQLITE_LIMIT_SQL_LENGTH 1 3581#define SQLITE_LIMIT_COLUMN 2 3582#define SQLITE_LIMIT_EXPR_DEPTH 3 3583#define SQLITE_LIMIT_COMPOUND_SELECT 4 3584#define SQLITE_LIMIT_VDBE_OP 5 3585#define SQLITE_LIMIT_FUNCTION_ARG 6 3586#define SQLITE_LIMIT_ATTACHED 7 3587#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3588#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3589#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3590#define SQLITE_LIMIT_WORKER_THREADS 11 3591 3592/* 3593** CAPI3REF: Prepare Flags 3594** 3595** These constants define various flags that can be passed into 3596** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3597** [sqlite3_prepare16_v3()] interfaces. 3598** 3599** New flags may be added in future releases of SQLite. 3600** 3601** <dl> 3602** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3603** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3604** that the prepared statement will be retained for a long time and 3605** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3606** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3607** be used just once or at most a few times and then destroyed using 3608** [sqlite3_finalize()] relatively soon. The current implementation acts 3609** on this hint by avoiding the use of [lookaside memory] so as not to 3610** deplete the limited store of lookaside memory. Future versions of 3611** SQLite may act on this hint differently. 3612** </dl> 3613*/ 3614#define SQLITE_PREPARE_PERSISTENT 0x01 3615 3616/* 3617** CAPI3REF: Compiling An SQL Statement 3618** KEYWORDS: {SQL statement compiler} 3619** METHOD: sqlite3 3620** CONSTRUCTOR: sqlite3_stmt 3621** 3622** To execute an SQL statement, it must first be compiled into a byte-code 3623** program using one of these routines. Or, in other words, these routines 3624** are constructors for the [prepared statement] object. 3625** 3626** The preferred routine to use is [sqlite3_prepare_v2()]. The 3627** [sqlite3_prepare()] interface is legacy and should be avoided. 3628** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3629** for special purposes. 3630** 3631** The use of the UTF-8 interfaces is preferred, as SQLite currently 3632** does all parsing using UTF-8. The UTF-16 interfaces are provided 3633** as a convenience. The UTF-16 interfaces work by converting the 3634** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3635** 3636** The first argument, "db", is a [database connection] obtained from a 3637** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3638** [sqlite3_open16()]. The database connection must not have been closed. 3639** 3640** The second argument, "zSql", is the statement to be compiled, encoded 3641** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 3642** and sqlite3_prepare_v3() 3643** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 3644** and sqlite3_prepare16_v3() use UTF-16. 3645** 3646** ^If the nByte argument is negative, then zSql is read up to the 3647** first zero terminator. ^If nByte is positive, then it is the 3648** number of bytes read from zSql. ^If nByte is zero, then no prepared 3649** statement is generated. 3650** If the caller knows that the supplied string is nul-terminated, then 3651** there is a small performance advantage to passing an nByte parameter that 3652** is the number of bytes in the input string <i>including</i> 3653** the nul-terminator. 3654** 3655** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3656** past the end of the first SQL statement in zSql. These routines only 3657** compile the first statement in zSql, so *pzTail is left pointing to 3658** what remains uncompiled. 3659** 3660** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3661** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3662** to NULL. ^If the input text contains no SQL (if the input is an empty 3663** string or a comment) then *ppStmt is set to NULL. 3664** The calling procedure is responsible for deleting the compiled 3665** SQL statement using [sqlite3_finalize()] after it has finished with it. 3666** ppStmt may not be NULL. 3667** 3668** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3669** otherwise an [error code] is returned. 3670** 3671** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 3672** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 3673** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 3674** are retained for backwards compatibility, but their use is discouraged. 3675** ^In the "vX" interfaces, the prepared statement 3676** that is returned (the [sqlite3_stmt] object) contains a copy of the 3677** original SQL text. This causes the [sqlite3_step()] interface to 3678** behave differently in three ways: 3679** 3680** <ol> 3681** <li> 3682** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3683** always used to do, [sqlite3_step()] will automatically recompile the SQL 3684** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3685** retries will occur before sqlite3_step() gives up and returns an error. 3686** </li> 3687** 3688** <li> 3689** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3690** [error codes] or [extended error codes]. ^The legacy behavior was that 3691** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3692** and the application would have to make a second call to [sqlite3_reset()] 3693** in order to find the underlying cause of the problem. With the "v2" prepare 3694** interfaces, the underlying reason for the error is returned immediately. 3695** </li> 3696** 3697** <li> 3698** ^If the specific value bound to [parameter | host parameter] in the 3699** WHERE clause might influence the choice of query plan for a statement, 3700** then the statement will be automatically recompiled, as if there had been 3701** a schema change, on the first [sqlite3_step()] call following any change 3702** to the [sqlite3_bind_text | bindings] of that [parameter]. 3703** ^The specific value of WHERE-clause [parameter] might influence the 3704** choice of query plan if the parameter is the left-hand side of a [LIKE] 3705** or [GLOB] operator or if the parameter is compared to an indexed column 3706** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3707** </li> 3708** </ol> 3709** 3710** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 3711** the extra prepFlags parameter, which is a bit array consisting of zero or 3712** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 3713** sqlite3_prepare_v2() interface works exactly the same as 3714** sqlite3_prepare_v3() with a zero prepFlags parameter. 3715*/ 3716int sqlite3_prepare( 3717 sqlite3 *db, /* Database handle */ 3718 const char *zSql, /* SQL statement, UTF-8 encoded */ 3719 int nByte, /* Maximum length of zSql in bytes. */ 3720 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3721 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3722); 3723int sqlite3_prepare_v2( 3724 sqlite3 *db, /* Database handle */ 3725 const char *zSql, /* SQL statement, UTF-8 encoded */ 3726 int nByte, /* Maximum length of zSql in bytes. */ 3727 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3728 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3729); 3730int sqlite3_prepare_v3( 3731 sqlite3 *db, /* Database handle */ 3732 const char *zSql, /* SQL statement, UTF-8 encoded */ 3733 int nByte, /* Maximum length of zSql in bytes. */ 3734 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3735 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3736 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3737); 3738int sqlite3_prepare16( 3739 sqlite3 *db, /* Database handle */ 3740 const void *zSql, /* SQL statement, UTF-16 encoded */ 3741 int nByte, /* Maximum length of zSql in bytes. */ 3742 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3743 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3744); 3745int sqlite3_prepare16_v2( 3746 sqlite3 *db, /* Database handle */ 3747 const void *zSql, /* SQL statement, UTF-16 encoded */ 3748 int nByte, /* Maximum length of zSql in bytes. */ 3749 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3750 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3751); 3752int sqlite3_prepare16_v3( 3753 sqlite3 *db, /* Database handle */ 3754 const void *zSql, /* SQL statement, UTF-16 encoded */ 3755 int nByte, /* Maximum length of zSql in bytes. */ 3756 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3757 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3758 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3759); 3760 3761/* 3762** CAPI3REF: Retrieving Statement SQL 3763** METHOD: sqlite3_stmt 3764** 3765** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 3766** SQL text used to create [prepared statement] P if P was 3767** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 3768** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 3769** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 3770** string containing the SQL text of prepared statement P with 3771** [bound parameters] expanded. 3772** 3773** ^(For example, if a prepared statement is created using the SQL 3774** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 3775** and parameter :xyz is unbound, then sqlite3_sql() will return 3776** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 3777** will return "SELECT 2345,NULL".)^ 3778** 3779** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 3780** is available to hold the result, or if the result would exceed the 3781** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 3782** 3783** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 3784** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 3785** option causes sqlite3_expanded_sql() to always return NULL. 3786** 3787** ^The string returned by sqlite3_sql(P) is managed by SQLite and is 3788** automatically freed when the prepared statement is finalized. 3789** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 3790** is obtained from [sqlite3_malloc()] and must be free by the application 3791** by passing it to [sqlite3_free()]. 3792*/ 3793const char *sqlite3_sql(sqlite3_stmt *pStmt); 3794char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 3795 3796/* 3797** CAPI3REF: Determine If An SQL Statement Writes The Database 3798** METHOD: sqlite3_stmt 3799** 3800** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3801** and only if the [prepared statement] X makes no direct changes to 3802** the content of the database file. 3803** 3804** Note that [application-defined SQL functions] or 3805** [virtual tables] might change the database indirectly as a side effect. 3806** ^(For example, if an application defines a function "eval()" that 3807** calls [sqlite3_exec()], then the following SQL statement would 3808** change the database file through side-effects: 3809** 3810** <blockquote><pre> 3811** SELECT eval('DELETE FROM t1') FROM t2; 3812** </pre></blockquote> 3813** 3814** But because the [SELECT] statement does not change the database file 3815** directly, sqlite3_stmt_readonly() would still return true.)^ 3816** 3817** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3818** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3819** since the statements themselves do not actually modify the database but 3820** rather they control the timing of when other statements modify the 3821** database. ^The [ATTACH] and [DETACH] statements also cause 3822** sqlite3_stmt_readonly() to return true since, while those statements 3823** change the configuration of a database connection, they do not make 3824** changes to the content of the database files on disk. 3825** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 3826** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 3827** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 3828** sqlite3_stmt_readonly() returns false for those commands. 3829*/ 3830int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3831 3832/* 3833** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3834** METHOD: sqlite3_stmt 3835** 3836** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3837** [prepared statement] S has been stepped at least once using 3838** [sqlite3_step(S)] but has neither run to completion (returned 3839** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3840** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3841** interface returns false if S is a NULL pointer. If S is not a 3842** NULL pointer and is not a pointer to a valid [prepared statement] 3843** object, then the behavior is undefined and probably undesirable. 3844** 3845** This interface can be used in combination [sqlite3_next_stmt()] 3846** to locate all prepared statements associated with a database 3847** connection that are in need of being reset. This can be used, 3848** for example, in diagnostic routines to search for prepared 3849** statements that are holding a transaction open. 3850*/ 3851int sqlite3_stmt_busy(sqlite3_stmt*); 3852 3853/* 3854** CAPI3REF: Dynamically Typed Value Object 3855** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3856** 3857** SQLite uses the sqlite3_value object to represent all values 3858** that can be stored in a database table. SQLite uses dynamic typing 3859** for the values it stores. ^Values stored in sqlite3_value objects 3860** can be integers, floating point values, strings, BLOBs, or NULL. 3861** 3862** An sqlite3_value object may be either "protected" or "unprotected". 3863** Some interfaces require a protected sqlite3_value. Other interfaces 3864** will accept either a protected or an unprotected sqlite3_value. 3865** Every interface that accepts sqlite3_value arguments specifies 3866** whether or not it requires a protected sqlite3_value. The 3867** [sqlite3_value_dup()] interface can be used to construct a new 3868** protected sqlite3_value from an unprotected sqlite3_value. 3869** 3870** The terms "protected" and "unprotected" refer to whether or not 3871** a mutex is held. An internal mutex is held for a protected 3872** sqlite3_value object but no mutex is held for an unprotected 3873** sqlite3_value object. If SQLite is compiled to be single-threaded 3874** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3875** or if SQLite is run in one of reduced mutex modes 3876** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3877** then there is no distinction between protected and unprotected 3878** sqlite3_value objects and they can be used interchangeably. However, 3879** for maximum code portability it is recommended that applications 3880** still make the distinction between protected and unprotected 3881** sqlite3_value objects even when not strictly required. 3882** 3883** ^The sqlite3_value objects that are passed as parameters into the 3884** implementation of [application-defined SQL functions] are protected. 3885** ^The sqlite3_value object returned by 3886** [sqlite3_column_value()] is unprotected. 3887** Unprotected sqlite3_value objects may only be used as arguments 3888** to [sqlite3_result_value()], [sqlite3_bind_value()], and 3889** [sqlite3_value_dup()]. 3890** The [sqlite3_value_blob | sqlite3_value_type()] family of 3891** interfaces require protected sqlite3_value objects. 3892*/ 3893typedef struct sqlite3_value sqlite3_value; 3894 3895/* 3896** CAPI3REF: SQL Function Context Object 3897** 3898** The context in which an SQL function executes is stored in an 3899** sqlite3_context object. ^A pointer to an sqlite3_context object 3900** is always first parameter to [application-defined SQL functions]. 3901** The application-defined SQL function implementation will pass this 3902** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3903** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3904** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3905** and/or [sqlite3_set_auxdata()]. 3906*/ 3907typedef struct sqlite3_context sqlite3_context; 3908 3909/* 3910** CAPI3REF: Binding Values To Prepared Statements 3911** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3912** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3913** METHOD: sqlite3_stmt 3914** 3915** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3916** literals may be replaced by a [parameter] that matches one of following 3917** templates: 3918** 3919** <ul> 3920** <li> ? 3921** <li> ?NNN 3922** <li> :VVV 3923** <li> @VVV 3924** <li> $VVV 3925** </ul> 3926** 3927** In the templates above, NNN represents an integer literal, 3928** and VVV represents an alphanumeric identifier.)^ ^The values of these 3929** parameters (also called "host parameter names" or "SQL parameters") 3930** can be set using the sqlite3_bind_*() routines defined here. 3931** 3932** ^The first argument to the sqlite3_bind_*() routines is always 3933** a pointer to the [sqlite3_stmt] object returned from 3934** [sqlite3_prepare_v2()] or its variants. 3935** 3936** ^The second argument is the index of the SQL parameter to be set. 3937** ^The leftmost SQL parameter has an index of 1. ^When the same named 3938** SQL parameter is used more than once, second and subsequent 3939** occurrences have the same index as the first occurrence. 3940** ^The index for named parameters can be looked up using the 3941** [sqlite3_bind_parameter_index()] API if desired. ^The index 3942** for "?NNN" parameters is the value of NNN. 3943** ^The NNN value must be between 1 and the [sqlite3_limit()] 3944** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3945** 3946** ^The third argument is the value to bind to the parameter. 3947** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3948** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3949** is ignored and the end result is the same as sqlite3_bind_null(). 3950** 3951** ^(In those routines that have a fourth argument, its value is the 3952** number of bytes in the parameter. To be clear: the value is the 3953** number of <u>bytes</u> in the value, not the number of characters.)^ 3954** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3955** is negative, then the length of the string is 3956** the number of bytes up to the first zero terminator. 3957** If the fourth parameter to sqlite3_bind_blob() is negative, then 3958** the behavior is undefined. 3959** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3960** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3961** that parameter must be the byte offset 3962** where the NUL terminator would occur assuming the string were NUL 3963** terminated. If any NUL characters occur at byte offsets less than 3964** the value of the fourth parameter then the resulting string value will 3965** contain embedded NULs. The result of expressions involving strings 3966** with embedded NULs is undefined. 3967** 3968** ^The fifth argument to the BLOB and string binding interfaces 3969** is a destructor used to dispose of the BLOB or 3970** string after SQLite has finished with it. ^The destructor is called 3971** to dispose of the BLOB or string even if the call to bind API fails. 3972** ^If the fifth argument is 3973** the special value [SQLITE_STATIC], then SQLite assumes that the 3974** information is in static, unmanaged space and does not need to be freed. 3975** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3976** SQLite makes its own private copy of the data immediately, before 3977** the sqlite3_bind_*() routine returns. 3978** 3979** ^The sixth argument to sqlite3_bind_text64() must be one of 3980** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3981** to specify the encoding of the text in the third parameter. If 3982** the sixth argument to sqlite3_bind_text64() is not one of the 3983** allowed values shown above, or if the text encoding is different 3984** from the encoding specified by the sixth parameter, then the behavior 3985** is undefined. 3986** 3987** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3988** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3989** (just an integer to hold its size) while it is being processed. 3990** Zeroblobs are intended to serve as placeholders for BLOBs whose 3991** content is later written using 3992** [sqlite3_blob_open | incremental BLOB I/O] routines. 3993** ^A negative value for the zeroblob results in a zero-length BLOB. 3994** 3995** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 3996** [prepared statement] S to have an SQL value of NULL, but to also be 3997** associated with the pointer P of type T. ^D is either a NULL pointer or 3998** a pointer to a destructor function for P. ^SQLite will invoke the 3999** destructor D with a single argument of P when it is finished using 4000** P. The T parameter should be a static string, preferably a string 4001** literal. The sqlite3_bind_pointer() routine is part of the 4002** [pointer passing interface] added for SQLite 3.20.0. 4003** 4004** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 4005** for the [prepared statement] or with a prepared statement for which 4006** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 4007** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 4008** routine is passed a [prepared statement] that has been finalized, the 4009** result is undefined and probably harmful. 4010** 4011** ^Bindings are not cleared by the [sqlite3_reset()] routine. 4012** ^Unbound parameters are interpreted as NULL. 4013** 4014** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 4015** [error code] if anything goes wrong. 4016** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 4017** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 4018** [SQLITE_MAX_LENGTH]. 4019** ^[SQLITE_RANGE] is returned if the parameter 4020** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 4021** 4022** See also: [sqlite3_bind_parameter_count()], 4023** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 4024*/ 4025int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 4026int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 4027 void(*)(void*)); 4028int sqlite3_bind_double(sqlite3_stmt*, int, double); 4029int sqlite3_bind_int(sqlite3_stmt*, int, int); 4030int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 4031int sqlite3_bind_null(sqlite3_stmt*, int); 4032int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 4033int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 4034int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 4035 void(*)(void*), unsigned char encoding); 4036int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 4037int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 4038int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 4039int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 4040 4041/* 4042** CAPI3REF: Number Of SQL Parameters 4043** METHOD: sqlite3_stmt 4044** 4045** ^This routine can be used to find the number of [SQL parameters] 4046** in a [prepared statement]. SQL parameters are tokens of the 4047** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 4048** placeholders for values that are [sqlite3_bind_blob | bound] 4049** to the parameters at a later time. 4050** 4051** ^(This routine actually returns the index of the largest (rightmost) 4052** parameter. For all forms except ?NNN, this will correspond to the 4053** number of unique parameters. If parameters of the ?NNN form are used, 4054** there may be gaps in the list.)^ 4055** 4056** See also: [sqlite3_bind_blob|sqlite3_bind()], 4057** [sqlite3_bind_parameter_name()], and 4058** [sqlite3_bind_parameter_index()]. 4059*/ 4060int sqlite3_bind_parameter_count(sqlite3_stmt*); 4061 4062/* 4063** CAPI3REF: Name Of A Host Parameter 4064** METHOD: sqlite3_stmt 4065** 4066** ^The sqlite3_bind_parameter_name(P,N) interface returns 4067** the name of the N-th [SQL parameter] in the [prepared statement] P. 4068** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 4069** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 4070** respectively. 4071** In other words, the initial ":" or "$" or "@" or "?" 4072** is included as part of the name.)^ 4073** ^Parameters of the form "?" without a following integer have no name 4074** and are referred to as "nameless" or "anonymous parameters". 4075** 4076** ^The first host parameter has an index of 1, not 0. 4077** 4078** ^If the value N is out of range or if the N-th parameter is 4079** nameless, then NULL is returned. ^The returned string is 4080** always in UTF-8 encoding even if the named parameter was 4081** originally specified as UTF-16 in [sqlite3_prepare16()], 4082** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4083** 4084** See also: [sqlite3_bind_blob|sqlite3_bind()], 4085** [sqlite3_bind_parameter_count()], and 4086** [sqlite3_bind_parameter_index()]. 4087*/ 4088const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 4089 4090/* 4091** CAPI3REF: Index Of A Parameter With A Given Name 4092** METHOD: sqlite3_stmt 4093** 4094** ^Return the index of an SQL parameter given its name. ^The 4095** index value returned is suitable for use as the second 4096** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4097** is returned if no matching parameter is found. ^The parameter 4098** name must be given in UTF-8 even if the original statement 4099** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4100** [sqlite3_prepare16_v3()]. 4101** 4102** See also: [sqlite3_bind_blob|sqlite3_bind()], 4103** [sqlite3_bind_parameter_count()], and 4104** [sqlite3_bind_parameter_name()]. 4105*/ 4106int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4107 4108/* 4109** CAPI3REF: Reset All Bindings On A Prepared Statement 4110** METHOD: sqlite3_stmt 4111** 4112** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4113** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4114** ^Use this routine to reset all host parameters to NULL. 4115*/ 4116int sqlite3_clear_bindings(sqlite3_stmt*); 4117 4118/* 4119** CAPI3REF: Number Of Columns In A Result Set 4120** METHOD: sqlite3_stmt 4121** 4122** ^Return the number of columns in the result set returned by the 4123** [prepared statement]. ^If this routine returns 0, that means the 4124** [prepared statement] returns no data (for example an [UPDATE]). 4125** ^However, just because this routine returns a positive number does not 4126** mean that one or more rows of data will be returned. ^A SELECT statement 4127** will always have a positive sqlite3_column_count() but depending on the 4128** WHERE clause constraints and the table content, it might return no rows. 4129** 4130** See also: [sqlite3_data_count()] 4131*/ 4132int sqlite3_column_count(sqlite3_stmt *pStmt); 4133 4134/* 4135** CAPI3REF: Column Names In A Result Set 4136** METHOD: sqlite3_stmt 4137** 4138** ^These routines return the name assigned to a particular column 4139** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4140** interface returns a pointer to a zero-terminated UTF-8 string 4141** and sqlite3_column_name16() returns a pointer to a zero-terminated 4142** UTF-16 string. ^The first parameter is the [prepared statement] 4143** that implements the [SELECT] statement. ^The second parameter is the 4144** column number. ^The leftmost column is number 0. 4145** 4146** ^The returned string pointer is valid until either the [prepared statement] 4147** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4148** reprepared by the first call to [sqlite3_step()] for a particular run 4149** or until the next call to 4150** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4151** 4152** ^If sqlite3_malloc() fails during the processing of either routine 4153** (for example during a conversion from UTF-8 to UTF-16) then a 4154** NULL pointer is returned. 4155** 4156** ^The name of a result column is the value of the "AS" clause for 4157** that column, if there is an AS clause. If there is no AS clause 4158** then the name of the column is unspecified and may change from 4159** one release of SQLite to the next. 4160*/ 4161const char *sqlite3_column_name(sqlite3_stmt*, int N); 4162const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4163 4164/* 4165** CAPI3REF: Source Of Data In A Query Result 4166** METHOD: sqlite3_stmt 4167** 4168** ^These routines provide a means to determine the database, table, and 4169** table column that is the origin of a particular result column in 4170** [SELECT] statement. 4171** ^The name of the database or table or column can be returned as 4172** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4173** the database name, the _table_ routines return the table name, and 4174** the origin_ routines return the column name. 4175** ^The returned string is valid until the [prepared statement] is destroyed 4176** using [sqlite3_finalize()] or until the statement is automatically 4177** reprepared by the first call to [sqlite3_step()] for a particular run 4178** or until the same information is requested 4179** again in a different encoding. 4180** 4181** ^The names returned are the original un-aliased names of the 4182** database, table, and column. 4183** 4184** ^The first argument to these interfaces is a [prepared statement]. 4185** ^These functions return information about the Nth result column returned by 4186** the statement, where N is the second function argument. 4187** ^The left-most column is column 0 for these routines. 4188** 4189** ^If the Nth column returned by the statement is an expression or 4190** subquery and is not a column value, then all of these functions return 4191** NULL. ^These routine might also return NULL if a memory allocation error 4192** occurs. ^Otherwise, they return the name of the attached database, table, 4193** or column that query result column was extracted from. 4194** 4195** ^As with all other SQLite APIs, those whose names end with "16" return 4196** UTF-16 encoded strings and the other functions return UTF-8. 4197** 4198** ^These APIs are only available if the library was compiled with the 4199** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4200** 4201** If two or more threads call one or more of these routines against the same 4202** prepared statement and column at the same time then the results are 4203** undefined. 4204** 4205** If two or more threads call one or more 4206** [sqlite3_column_database_name | column metadata interfaces] 4207** for the same [prepared statement] and result column 4208** at the same time then the results are undefined. 4209*/ 4210const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4211const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4212const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4213const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4214const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4215const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4216 4217/* 4218** CAPI3REF: Declared Datatype Of A Query Result 4219** METHOD: sqlite3_stmt 4220** 4221** ^(The first parameter is a [prepared statement]. 4222** If this statement is a [SELECT] statement and the Nth column of the 4223** returned result set of that [SELECT] is a table column (not an 4224** expression or subquery) then the declared type of the table 4225** column is returned.)^ ^If the Nth column of the result set is an 4226** expression or subquery, then a NULL pointer is returned. 4227** ^The returned string is always UTF-8 encoded. 4228** 4229** ^(For example, given the database schema: 4230** 4231** CREATE TABLE t1(c1 VARIANT); 4232** 4233** and the following statement to be compiled: 4234** 4235** SELECT c1 + 1, c1 FROM t1; 4236** 4237** this routine would return the string "VARIANT" for the second result 4238** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4239** 4240** ^SQLite uses dynamic run-time typing. ^So just because a column 4241** is declared to contain a particular type does not mean that the 4242** data stored in that column is of the declared type. SQLite is 4243** strongly typed, but the typing is dynamic not static. ^Type 4244** is associated with individual values, not with the containers 4245** used to hold those values. 4246*/ 4247const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4248const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4249 4250/* 4251** CAPI3REF: Evaluate An SQL Statement 4252** METHOD: sqlite3_stmt 4253** 4254** After a [prepared statement] has been prepared using any of 4255** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4256** or [sqlite3_prepare16_v3()] or one of the legacy 4257** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4258** must be called one or more times to evaluate the statement. 4259** 4260** The details of the behavior of the sqlite3_step() interface depend 4261** on whether the statement was prepared using the newer "vX" interfaces 4262** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4263** [sqlite3_prepare16_v2()] or the older legacy 4264** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4265** new "vX" interface is recommended for new applications but the legacy 4266** interface will continue to be supported. 4267** 4268** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4269** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4270** ^With the "v2" interface, any of the other [result codes] or 4271** [extended result codes] might be returned as well. 4272** 4273** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4274** database locks it needs to do its job. ^If the statement is a [COMMIT] 4275** or occurs outside of an explicit transaction, then you can retry the 4276** statement. If the statement is not a [COMMIT] and occurs within an 4277** explicit transaction then you should rollback the transaction before 4278** continuing. 4279** 4280** ^[SQLITE_DONE] means that the statement has finished executing 4281** successfully. sqlite3_step() should not be called again on this virtual 4282** machine without first calling [sqlite3_reset()] to reset the virtual 4283** machine back to its initial state. 4284** 4285** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4286** is returned each time a new row of data is ready for processing by the 4287** caller. The values may be accessed using the [column access functions]. 4288** sqlite3_step() is called again to retrieve the next row of data. 4289** 4290** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4291** violation) has occurred. sqlite3_step() should not be called again on 4292** the VM. More information may be found by calling [sqlite3_errmsg()]. 4293** ^With the legacy interface, a more specific error code (for example, 4294** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4295** can be obtained by calling [sqlite3_reset()] on the 4296** [prepared statement]. ^In the "v2" interface, 4297** the more specific error code is returned directly by sqlite3_step(). 4298** 4299** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4300** Perhaps it was called on a [prepared statement] that has 4301** already been [sqlite3_finalize | finalized] or on one that had 4302** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4303** be the case that the same database connection is being used by two or 4304** more threads at the same moment in time. 4305** 4306** For all versions of SQLite up to and including 3.6.23.1, a call to 4307** [sqlite3_reset()] was required after sqlite3_step() returned anything 4308** other than [SQLITE_ROW] before any subsequent invocation of 4309** sqlite3_step(). Failure to reset the prepared statement using 4310** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4311** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4312** sqlite3_step() began 4313** calling [sqlite3_reset()] automatically in this circumstance rather 4314** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4315** break because any application that ever receives an SQLITE_MISUSE error 4316** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4317** can be used to restore the legacy behavior. 4318** 4319** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4320** API always returns a generic error code, [SQLITE_ERROR], following any 4321** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4322** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4323** specific [error codes] that better describes the error. 4324** We admit that this is a goofy design. The problem has been fixed 4325** with the "v2" interface. If you prepare all of your SQL statements 4326** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4327** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4328** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4329** then the more specific [error codes] are returned directly 4330** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4331*/ 4332int sqlite3_step(sqlite3_stmt*); 4333 4334/* 4335** CAPI3REF: Number of columns in a result set 4336** METHOD: sqlite3_stmt 4337** 4338** ^The sqlite3_data_count(P) interface returns the number of columns in the 4339** current row of the result set of [prepared statement] P. 4340** ^If prepared statement P does not have results ready to return 4341** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 4342** interfaces) then sqlite3_data_count(P) returns 0. 4343** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4344** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4345** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4346** will return non-zero if previous call to [sqlite3_step](P) returned 4347** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4348** where it always returns zero since each step of that multi-step 4349** pragma returns 0 columns of data. 4350** 4351** See also: [sqlite3_column_count()] 4352*/ 4353int sqlite3_data_count(sqlite3_stmt *pStmt); 4354 4355/* 4356** CAPI3REF: Fundamental Datatypes 4357** KEYWORDS: SQLITE_TEXT 4358** 4359** ^(Every value in SQLite has one of five fundamental datatypes: 4360** 4361** <ul> 4362** <li> 64-bit signed integer 4363** <li> 64-bit IEEE floating point number 4364** <li> string 4365** <li> BLOB 4366** <li> NULL 4367** </ul>)^ 4368** 4369** These constants are codes for each of those types. 4370** 4371** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4372** for a completely different meaning. Software that links against both 4373** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4374** SQLITE_TEXT. 4375*/ 4376#define SQLITE_INTEGER 1 4377#define SQLITE_FLOAT 2 4378#define SQLITE_BLOB 4 4379#define SQLITE_NULL 5 4380#ifdef SQLITE_TEXT 4381# undef SQLITE_TEXT 4382#else 4383# define SQLITE_TEXT 3 4384#endif 4385#define SQLITE3_TEXT 3 4386 4387/* 4388** CAPI3REF: Result Values From A Query 4389** KEYWORDS: {column access functions} 4390** METHOD: sqlite3_stmt 4391** 4392** <b>Summary:</b> 4393** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4394** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4395** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4396** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4397** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4398** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4399** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4400** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4401** [sqlite3_value|unprotected sqlite3_value] object. 4402** <tr><td> <td> <td> 4403** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4404** or a UTF-8 TEXT result in bytes 4405** <tr><td><b>sqlite3_column_bytes16 </b> 4406** <td>→ <td>Size of UTF-16 4407** TEXT in bytes 4408** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4409** datatype of the result 4410** </table></blockquote> 4411** 4412** <b>Details:</b> 4413** 4414** ^These routines return information about a single column of the current 4415** result row of a query. ^In every case the first argument is a pointer 4416** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4417** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4418** and the second argument is the index of the column for which information 4419** should be returned. ^The leftmost column of the result set has the index 0. 4420** ^The number of columns in the result can be determined using 4421** [sqlite3_column_count()]. 4422** 4423** If the SQL statement does not currently point to a valid row, or if the 4424** column index is out of range, the result is undefined. 4425** These routines may only be called when the most recent call to 4426** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4427** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4428** If any of these routines are called after [sqlite3_reset()] or 4429** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4430** something other than [SQLITE_ROW], the results are undefined. 4431** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4432** are called from a different thread while any of these routines 4433** are pending, then the results are undefined. 4434** 4435** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4436** each return the value of a result column in a specific data format. If 4437** the result column is not initially in the requested format (for example, 4438** if the query returns an integer but the sqlite3_column_text() interface 4439** is used to extract the value) then an automatic type conversion is performed. 4440** 4441** ^The sqlite3_column_type() routine returns the 4442** [SQLITE_INTEGER | datatype code] for the initial data type 4443** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4444** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4445** The return value of sqlite3_column_type() can be used to decide which 4446** of the first six interface should be used to extract the column value. 4447** The value returned by sqlite3_column_type() is only meaningful if no 4448** automatic type conversions have occurred for the value in question. 4449** After a type conversion, the result of calling sqlite3_column_type() 4450** is undefined, though harmless. Future 4451** versions of SQLite may change the behavior of sqlite3_column_type() 4452** following a type conversion. 4453** 4454** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4455** or sqlite3_column_bytes16() interfaces can be used to determine the size 4456** of that BLOB or string. 4457** 4458** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4459** routine returns the number of bytes in that BLOB or string. 4460** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4461** the string to UTF-8 and then returns the number of bytes. 4462** ^If the result is a numeric value then sqlite3_column_bytes() uses 4463** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4464** the number of bytes in that string. 4465** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4466** 4467** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4468** routine returns the number of bytes in that BLOB or string. 4469** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4470** the string to UTF-16 and then returns the number of bytes. 4471** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4472** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4473** the number of bytes in that string. 4474** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4475** 4476** ^The values returned by [sqlite3_column_bytes()] and 4477** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4478** of the string. ^For clarity: the values returned by 4479** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4480** bytes in the string, not the number of characters. 4481** 4482** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4483** even empty strings, are always zero-terminated. ^The return 4484** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4485** 4486** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4487** [unprotected sqlite3_value] object. In a multithreaded environment, 4488** an unprotected sqlite3_value object may only be used safely with 4489** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4490** If the [unprotected sqlite3_value] object returned by 4491** [sqlite3_column_value()] is used in any other way, including calls 4492** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4493** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4494** Hence, the sqlite3_column_value() interface 4495** is normally only useful within the implementation of 4496** [application-defined SQL functions] or [virtual tables], not within 4497** top-level application code. 4498** 4499** The these routines may attempt to convert the datatype of the result. 4500** ^For example, if the internal representation is FLOAT and a text result 4501** is requested, [sqlite3_snprintf()] is used internally to perform the 4502** conversion automatically. ^(The following table details the conversions 4503** that are applied: 4504** 4505** <blockquote> 4506** <table border="1"> 4507** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4508** 4509** <tr><td> NULL <td> INTEGER <td> Result is 0 4510** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4511** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4512** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4513** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4514** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4515** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4516** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4517** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4518** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4519** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4520** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4521** <tr><td> TEXT <td> BLOB <td> No change 4522** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4523** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4524** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4525** </table> 4526** </blockquote>)^ 4527** 4528** Note that when type conversions occur, pointers returned by prior 4529** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4530** sqlite3_column_text16() may be invalidated. 4531** Type conversions and pointer invalidations might occur 4532** in the following cases: 4533** 4534** <ul> 4535** <li> The initial content is a BLOB and sqlite3_column_text() or 4536** sqlite3_column_text16() is called. A zero-terminator might 4537** need to be added to the string.</li> 4538** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4539** sqlite3_column_text16() is called. The content must be converted 4540** to UTF-16.</li> 4541** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4542** sqlite3_column_text() is called. The content must be converted 4543** to UTF-8.</li> 4544** </ul> 4545** 4546** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4547** not invalidate a prior pointer, though of course the content of the buffer 4548** that the prior pointer references will have been modified. Other kinds 4549** of conversion are done in place when it is possible, but sometimes they 4550** are not possible and in those cases prior pointers are invalidated. 4551** 4552** The safest policy is to invoke these routines 4553** in one of the following ways: 4554** 4555** <ul> 4556** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4557** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4558** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4559** </ul> 4560** 4561** In other words, you should call sqlite3_column_text(), 4562** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4563** into the desired format, then invoke sqlite3_column_bytes() or 4564** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4565** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4566** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4567** with calls to sqlite3_column_bytes(). 4568** 4569** ^The pointers returned are valid until a type conversion occurs as 4570** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4571** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4572** and BLOBs is freed automatically. Do not pass the pointers returned 4573** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4574** [sqlite3_free()]. 4575** 4576** As long as the input parameters are correct, these routines will only 4577** fail if an out-of-memory error occurs during a format conversion. 4578** Only the following subset of interfaces are subject to out-of-memory 4579** errors: 4580** 4581** <ul> 4582** <li> sqlite3_column_blob() 4583** <li> sqlite3_column_text() 4584** <li> sqlite3_column_text16() 4585** <li> sqlite3_column_bytes() 4586** <li> sqlite3_column_bytes16() 4587** </ul> 4588** 4589** If an out-of-memory error occurs, then the return value from these 4590** routines is the same as if the column had contained an SQL NULL value. 4591** Valid SQL NULL returns can be distinguished from out-of-memory errors 4592** by invoking the [sqlite3_errcode()] immediately after the suspect 4593** return value is obtained and before any 4594** other SQLite interface is called on the same [database connection]. 4595*/ 4596const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4597double sqlite3_column_double(sqlite3_stmt*, int iCol); 4598int sqlite3_column_int(sqlite3_stmt*, int iCol); 4599sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4600const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4601const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4602sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4603int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4604int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4605int sqlite3_column_type(sqlite3_stmt*, int iCol); 4606 4607/* 4608** CAPI3REF: Destroy A Prepared Statement Object 4609** DESTRUCTOR: sqlite3_stmt 4610** 4611** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4612** ^If the most recent evaluation of the statement encountered no errors 4613** or if the statement is never been evaluated, then sqlite3_finalize() returns 4614** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4615** sqlite3_finalize(S) returns the appropriate [error code] or 4616** [extended error code]. 4617** 4618** ^The sqlite3_finalize(S) routine can be called at any point during 4619** the life cycle of [prepared statement] S: 4620** before statement S is ever evaluated, after 4621** one or more calls to [sqlite3_reset()], or after any call 4622** to [sqlite3_step()] regardless of whether or not the statement has 4623** completed execution. 4624** 4625** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4626** 4627** The application must finalize every [prepared statement] in order to avoid 4628** resource leaks. It is a grievous error for the application to try to use 4629** a prepared statement after it has been finalized. Any use of a prepared 4630** statement after it has been finalized can result in undefined and 4631** undesirable behavior such as segfaults and heap corruption. 4632*/ 4633int sqlite3_finalize(sqlite3_stmt *pStmt); 4634 4635/* 4636** CAPI3REF: Reset A Prepared Statement Object 4637** METHOD: sqlite3_stmt 4638** 4639** The sqlite3_reset() function is called to reset a [prepared statement] 4640** object back to its initial state, ready to be re-executed. 4641** ^Any SQL statement variables that had values bound to them using 4642** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4643** Use [sqlite3_clear_bindings()] to reset the bindings. 4644** 4645** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4646** back to the beginning of its program. 4647** 4648** ^If the most recent call to [sqlite3_step(S)] for the 4649** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4650** or if [sqlite3_step(S)] has never before been called on S, 4651** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4652** 4653** ^If the most recent call to [sqlite3_step(S)] for the 4654** [prepared statement] S indicated an error, then 4655** [sqlite3_reset(S)] returns an appropriate [error code]. 4656** 4657** ^The [sqlite3_reset(S)] interface does not change the values 4658** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4659*/ 4660int sqlite3_reset(sqlite3_stmt *pStmt); 4661 4662/* 4663** CAPI3REF: Create Or Redefine SQL Functions 4664** KEYWORDS: {function creation routines} 4665** KEYWORDS: {application-defined SQL function} 4666** KEYWORDS: {application-defined SQL functions} 4667** METHOD: sqlite3 4668** 4669** ^These functions (collectively known as "function creation routines") 4670** are used to add SQL functions or aggregates or to redefine the behavior 4671** of existing SQL functions or aggregates. The only differences between 4672** the three "sqlite3_create_function*" routines are the text encoding 4673** expected for the second parameter (the name of the function being 4674** created) and the presence or absence of a destructor callback for 4675** the application data pointer. Function sqlite3_create_window_function() 4676** is similar, but allows the user to supply the extra callback functions 4677** needed by [aggregate window functions]. 4678** 4679** ^The first parameter is the [database connection] to which the SQL 4680** function is to be added. ^If an application uses more than one database 4681** connection then application-defined SQL functions must be added 4682** to each database connection separately. 4683** 4684** ^The second parameter is the name of the SQL function to be created or 4685** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4686** representation, exclusive of the zero-terminator. ^Note that the name 4687** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4688** ^Any attempt to create a function with a longer name 4689** will result in [SQLITE_MISUSE] being returned. 4690** 4691** ^The third parameter (nArg) 4692** is the number of arguments that the SQL function or 4693** aggregate takes. ^If this parameter is -1, then the SQL function or 4694** aggregate may take any number of arguments between 0 and the limit 4695** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4696** parameter is less than -1 or greater than 127 then the behavior is 4697** undefined. 4698** 4699** ^The fourth parameter, eTextRep, specifies what 4700** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4701** its parameters. The application should set this parameter to 4702** [SQLITE_UTF16LE] if the function implementation invokes 4703** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4704** implementation invokes [sqlite3_value_text16be()] on an input, or 4705** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4706** otherwise. ^The same SQL function may be registered multiple times using 4707** different preferred text encodings, with different implementations for 4708** each encoding. 4709** ^When multiple implementations of the same function are available, SQLite 4710** will pick the one that involves the least amount of data conversion. 4711** 4712** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4713** to signal that the function will always return the same result given 4714** the same inputs within a single SQL statement. Most SQL functions are 4715** deterministic. The built-in [random()] SQL function is an example of a 4716** function that is not deterministic. The SQLite query planner is able to 4717** perform additional optimizations on deterministic functions, so use 4718** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4719** 4720** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4721** function can gain access to this pointer using [sqlite3_user_data()].)^ 4722** 4723** ^The sixth, seventh and eighth parameters passed to the three 4724** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are 4725** pointers to C-language functions that implement the SQL function or 4726** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4727** callback only; NULL pointers must be passed as the xStep and xFinal 4728** parameters. ^An aggregate SQL function requires an implementation of xStep 4729** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4730** SQL function or aggregate, pass NULL pointers for all three function 4731** callbacks. 4732** 4733** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue 4734** and xInverse) passed to sqlite3_create_window_function are pointers to 4735** C-language callbacks that implement the new function. xStep and xFinal 4736** must both be non-NULL. xValue and xInverse may either both be NULL, in 4737** which case a regular aggregate function is created, or must both be 4738** non-NULL, in which case the new function may be used as either an aggregate 4739** or aggregate window function. More details regarding the implementation 4740** of aggregate window functions are 4741** [user-defined window functions|available here]. 4742** 4743** ^(If the final parameter to sqlite3_create_function_v2() or 4744** sqlite3_create_window_function() is not NULL, then it is destructor for 4745** the application data pointer. The destructor is invoked when the function 4746** is deleted, either by being overloaded or when the database connection 4747** closes.)^ ^The destructor is also invoked if the call to 4748** sqlite3_create_function_v2() fails. ^When the destructor callback is 4749** invoked, it is passed a single argument which is a copy of the application 4750** data pointer which was the fifth parameter to sqlite3_create_function_v2(). 4751** 4752** ^It is permitted to register multiple implementations of the same 4753** functions with the same name but with either differing numbers of 4754** arguments or differing preferred text encodings. ^SQLite will use 4755** the implementation that most closely matches the way in which the 4756** SQL function is used. ^A function implementation with a non-negative 4757** nArg parameter is a better match than a function implementation with 4758** a negative nArg. ^A function where the preferred text encoding 4759** matches the database encoding is a better 4760** match than a function where the encoding is different. 4761** ^A function where the encoding difference is between UTF16le and UTF16be 4762** is a closer match than a function where the encoding difference is 4763** between UTF8 and UTF16. 4764** 4765** ^Built-in functions may be overloaded by new application-defined functions. 4766** 4767** ^An application-defined function is permitted to call other 4768** SQLite interfaces. However, such calls must not 4769** close the database connection nor finalize or reset the prepared 4770** statement in which the function is running. 4771*/ 4772int sqlite3_create_function( 4773 sqlite3 *db, 4774 const char *zFunctionName, 4775 int nArg, 4776 int eTextRep, 4777 void *pApp, 4778 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4779 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4780 void (*xFinal)(sqlite3_context*) 4781); 4782int sqlite3_create_function16( 4783 sqlite3 *db, 4784 const void *zFunctionName, 4785 int nArg, 4786 int eTextRep, 4787 void *pApp, 4788 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4789 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4790 void (*xFinal)(sqlite3_context*) 4791); 4792int sqlite3_create_function_v2( 4793 sqlite3 *db, 4794 const char *zFunctionName, 4795 int nArg, 4796 int eTextRep, 4797 void *pApp, 4798 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4799 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4800 void (*xFinal)(sqlite3_context*), 4801 void(*xDestroy)(void*) 4802); 4803int sqlite3_create_window_function( 4804 sqlite3 *db, 4805 const char *zFunctionName, 4806 int nArg, 4807 int eTextRep, 4808 void *pApp, 4809 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4810 void (*xFinal)(sqlite3_context*), 4811 void (*xValue)(sqlite3_context*), 4812 void (*xInverse)(sqlite3_context*,int,sqlite3_value**), 4813 void(*xDestroy)(void*) 4814); 4815 4816/* 4817** CAPI3REF: Text Encodings 4818** 4819** These constant define integer codes that represent the various 4820** text encodings supported by SQLite. 4821*/ 4822#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4823#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4824#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4825#define SQLITE_UTF16 4 /* Use native byte order */ 4826#define SQLITE_ANY 5 /* Deprecated */ 4827#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4828 4829/* 4830** CAPI3REF: Function Flags 4831** 4832** These constants may be ORed together with the 4833** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4834** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4835** [sqlite3_create_function_v2()]. 4836*/ 4837#define SQLITE_DETERMINISTIC 0x800 4838 4839/* 4840** CAPI3REF: Deprecated Functions 4841** DEPRECATED 4842** 4843** These functions are [deprecated]. In order to maintain 4844** backwards compatibility with older code, these functions continue 4845** to be supported. However, new applications should avoid 4846** the use of these functions. To encourage programmers to avoid 4847** these functions, we will not explain what they do. 4848*/ 4849#ifndef SQLITE_OMIT_DEPRECATED 4850SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4851SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4852SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4853SQLITE_DEPRECATED int sqlite3_global_recover(void); 4854SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4855SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4856 void*,sqlite3_int64); 4857#endif 4858 4859/* 4860** CAPI3REF: Obtaining SQL Values 4861** METHOD: sqlite3_value 4862** 4863** <b>Summary:</b> 4864** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4865** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 4866** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 4867** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 4868** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 4869** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 4870** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 4871** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 4872** the native byteorder 4873** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 4874** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 4875** <tr><td> <td> <td> 4876** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 4877** or a UTF-8 TEXT in bytes 4878** <tr><td><b>sqlite3_value_bytes16 </b> 4879** <td>→ <td>Size of UTF-16 4880** TEXT in bytes 4881** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 4882** datatype of the value 4883** <tr><td><b>sqlite3_value_numeric_type </b> 4884** <td>→ <td>Best numeric datatype of the value 4885** <tr><td><b>sqlite3_value_nochange </b> 4886** <td>→ <td>True if the column is unchanged in an UPDATE 4887** against a virtual table. 4888** </table></blockquote> 4889** 4890** <b>Details:</b> 4891** 4892** These routines extract type, size, and content information from 4893** [protected sqlite3_value] objects. Protected sqlite3_value objects 4894** are used to pass parameter information into implementation of 4895** [application-defined SQL functions] and [virtual tables]. 4896** 4897** These routines work only with [protected sqlite3_value] objects. 4898** Any attempt to use these routines on an [unprotected sqlite3_value] 4899** is not threadsafe. 4900** 4901** ^These routines work just like the corresponding [column access functions] 4902** except that these routines take a single [protected sqlite3_value] object 4903** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4904** 4905** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4906** in the native byte-order of the host machine. ^The 4907** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4908** extract UTF-16 strings as big-endian and little-endian respectively. 4909** 4910** ^If [sqlite3_value] object V was initialized 4911** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 4912** and if X and Y are strings that compare equal according to strcmp(X,Y), 4913** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 4914** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 4915** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 4916** 4917** ^(The sqlite3_value_type(V) interface returns the 4918** [SQLITE_INTEGER | datatype code] for the initial datatype of the 4919** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 4920** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 4921** Other interfaces might change the datatype for an sqlite3_value object. 4922** For example, if the datatype is initially SQLITE_INTEGER and 4923** sqlite3_value_text(V) is called to extract a text value for that 4924** integer, then subsequent calls to sqlite3_value_type(V) might return 4925** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 4926** occurs is undefined and may change from one release of SQLite to the next. 4927** 4928** ^(The sqlite3_value_numeric_type() interface attempts to apply 4929** numeric affinity to the value. This means that an attempt is 4930** made to convert the value to an integer or floating point. If 4931** such a conversion is possible without loss of information (in other 4932** words, if the value is a string that looks like a number) 4933** then the conversion is performed. Otherwise no conversion occurs. 4934** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4935** 4936** ^Within the [xUpdate] method of a [virtual table], the 4937** sqlite3_value_nochange(X) interface returns true if and only if 4938** the column corresponding to X is unchanged by the UPDATE operation 4939** that the xUpdate method call was invoked to implement and if 4940** and the prior [xColumn] method call that was invoked to extracted 4941** the value for that column returned without setting a result (probably 4942** because it queried [sqlite3_vtab_nochange()] and found that the column 4943** was unchanging). ^Within an [xUpdate] method, any value for which 4944** sqlite3_value_nochange(X) is true will in all other respects appear 4945** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other 4946** than within an [xUpdate] method call for an UPDATE statement, then 4947** the return value is arbitrary and meaningless. 4948** 4949** Please pay particular attention to the fact that the pointer returned 4950** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4951** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4952** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4953** or [sqlite3_value_text16()]. 4954** 4955** These routines must be called from the same thread as 4956** the SQL function that supplied the [sqlite3_value*] parameters. 4957** 4958** As long as the input parameter is correct, these routines can only 4959** fail if an out-of-memory error occurs during a format conversion. 4960** Only the following subset of interfaces are subject to out-of-memory 4961** errors: 4962** 4963** <ul> 4964** <li> sqlite3_value_blob() 4965** <li> sqlite3_value_text() 4966** <li> sqlite3_value_text16() 4967** <li> sqlite3_value_text16le() 4968** <li> sqlite3_value_text16be() 4969** <li> sqlite3_value_bytes() 4970** <li> sqlite3_value_bytes16() 4971** </ul> 4972** 4973** If an out-of-memory error occurs, then the return value from these 4974** routines is the same as if the column had contained an SQL NULL value. 4975** Valid SQL NULL returns can be distinguished from out-of-memory errors 4976** by invoking the [sqlite3_errcode()] immediately after the suspect 4977** return value is obtained and before any 4978** other SQLite interface is called on the same [database connection]. 4979*/ 4980const void *sqlite3_value_blob(sqlite3_value*); 4981double sqlite3_value_double(sqlite3_value*); 4982int sqlite3_value_int(sqlite3_value*); 4983sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4984void *sqlite3_value_pointer(sqlite3_value*, const char*); 4985const unsigned char *sqlite3_value_text(sqlite3_value*); 4986const void *sqlite3_value_text16(sqlite3_value*); 4987const void *sqlite3_value_text16le(sqlite3_value*); 4988const void *sqlite3_value_text16be(sqlite3_value*); 4989int sqlite3_value_bytes(sqlite3_value*); 4990int sqlite3_value_bytes16(sqlite3_value*); 4991int sqlite3_value_type(sqlite3_value*); 4992int sqlite3_value_numeric_type(sqlite3_value*); 4993int sqlite3_value_nochange(sqlite3_value*); 4994 4995/* 4996** CAPI3REF: Finding The Subtype Of SQL Values 4997** METHOD: sqlite3_value 4998** 4999** The sqlite3_value_subtype(V) function returns the subtype for 5000** an [application-defined SQL function] argument V. The subtype 5001** information can be used to pass a limited amount of context from 5002** one SQL function to another. Use the [sqlite3_result_subtype()] 5003** routine to set the subtype for the return value of an SQL function. 5004*/ 5005unsigned int sqlite3_value_subtype(sqlite3_value*); 5006 5007/* 5008** CAPI3REF: Copy And Free SQL Values 5009** METHOD: sqlite3_value 5010** 5011** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 5012** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 5013** is a [protected sqlite3_value] object even if the input is not. 5014** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 5015** memory allocation fails. 5016** 5017** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 5018** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 5019** then sqlite3_value_free(V) is a harmless no-op. 5020*/ 5021sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 5022void sqlite3_value_free(sqlite3_value*); 5023 5024/* 5025** CAPI3REF: Obtain Aggregate Function Context 5026** METHOD: sqlite3_context 5027** 5028** Implementations of aggregate SQL functions use this 5029** routine to allocate memory for storing their state. 5030** 5031** ^The first time the sqlite3_aggregate_context(C,N) routine is called 5032** for a particular aggregate function, SQLite 5033** allocates N of memory, zeroes out that memory, and returns a pointer 5034** to the new memory. ^On second and subsequent calls to 5035** sqlite3_aggregate_context() for the same aggregate function instance, 5036** the same buffer is returned. Sqlite3_aggregate_context() is normally 5037** called once for each invocation of the xStep callback and then one 5038** last time when the xFinal callback is invoked. ^(When no rows match 5039** an aggregate query, the xStep() callback of the aggregate function 5040** implementation is never called and xFinal() is called exactly once. 5041** In those cases, sqlite3_aggregate_context() might be called for the 5042** first time from within xFinal().)^ 5043** 5044** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 5045** when first called if N is less than or equal to zero or if a memory 5046** allocate error occurs. 5047** 5048** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 5049** determined by the N parameter on first successful call. Changing the 5050** value of N in subsequent call to sqlite3_aggregate_context() within 5051** the same aggregate function instance will not resize the memory 5052** allocation.)^ Within the xFinal callback, it is customary to set 5053** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 5054** pointless memory allocations occur. 5055** 5056** ^SQLite automatically frees the memory allocated by 5057** sqlite3_aggregate_context() when the aggregate query concludes. 5058** 5059** The first parameter must be a copy of the 5060** [sqlite3_context | SQL function context] that is the first parameter 5061** to the xStep or xFinal callback routine that implements the aggregate 5062** function. 5063** 5064** This routine must be called from the same thread in which 5065** the aggregate SQL function is running. 5066*/ 5067void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 5068 5069/* 5070** CAPI3REF: User Data For Functions 5071** METHOD: sqlite3_context 5072** 5073** ^The sqlite3_user_data() interface returns a copy of 5074** the pointer that was the pUserData parameter (the 5th parameter) 5075** of the [sqlite3_create_function()] 5076** and [sqlite3_create_function16()] routines that originally 5077** registered the application defined function. 5078** 5079** This routine must be called from the same thread in which 5080** the application-defined function is running. 5081*/ 5082void *sqlite3_user_data(sqlite3_context*); 5083 5084/* 5085** CAPI3REF: Database Connection For Functions 5086** METHOD: sqlite3_context 5087** 5088** ^The sqlite3_context_db_handle() interface returns a copy of 5089** the pointer to the [database connection] (the 1st parameter) 5090** of the [sqlite3_create_function()] 5091** and [sqlite3_create_function16()] routines that originally 5092** registered the application defined function. 5093*/ 5094sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 5095 5096/* 5097** CAPI3REF: Function Auxiliary Data 5098** METHOD: sqlite3_context 5099** 5100** These functions may be used by (non-aggregate) SQL functions to 5101** associate metadata with argument values. If the same value is passed to 5102** multiple invocations of the same SQL function during query execution, under 5103** some circumstances the associated metadata may be preserved. An example 5104** of where this might be useful is in a regular-expression matching 5105** function. The compiled version of the regular expression can be stored as 5106** metadata associated with the pattern string. 5107** Then as long as the pattern string remains the same, 5108** the compiled regular expression can be reused on multiple 5109** invocations of the same function. 5110** 5111** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 5112** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 5113** value to the application-defined function. ^N is zero for the left-most 5114** function argument. ^If there is no metadata 5115** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 5116** returns a NULL pointer. 5117** 5118** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 5119** argument of the application-defined function. ^Subsequent 5120** calls to sqlite3_get_auxdata(C,N) return P from the most recent 5121** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 5122** NULL if the metadata has been discarded. 5123** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 5124** SQLite will invoke the destructor function X with parameter P exactly 5125** once, when the metadata is discarded. 5126** SQLite is free to discard the metadata at any time, including: <ul> 5127** <li> ^(when the corresponding function parameter changes)^, or 5128** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 5129** SQL statement)^, or 5130** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 5131** parameter)^, or 5132** <li> ^(during the original sqlite3_set_auxdata() call when a memory 5133** allocation error occurs.)^ </ul> 5134** 5135** Note the last bullet in particular. The destructor X in 5136** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 5137** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 5138** should be called near the end of the function implementation and the 5139** function implementation should not make any use of P after 5140** sqlite3_set_auxdata() has been called. 5141** 5142** ^(In practice, metadata is preserved between function calls for 5143** function parameters that are compile-time constants, including literal 5144** values and [parameters] and expressions composed from the same.)^ 5145** 5146** The value of the N parameter to these interfaces should be non-negative. 5147** Future enhancements may make use of negative N values to define new 5148** kinds of function caching behavior. 5149** 5150** These routines must be called from the same thread in which 5151** the SQL function is running. 5152*/ 5153void *sqlite3_get_auxdata(sqlite3_context*, int N); 5154void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5155 5156 5157/* 5158** CAPI3REF: Constants Defining Special Destructor Behavior 5159** 5160** These are special values for the destructor that is passed in as the 5161** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5162** argument is SQLITE_STATIC, it means that the content pointer is constant 5163** and will never change. It does not need to be destroyed. ^The 5164** SQLITE_TRANSIENT value means that the content will likely change in 5165** the near future and that SQLite should make its own private copy of 5166** the content before returning. 5167** 5168** The typedef is necessary to work around problems in certain 5169** C++ compilers. 5170*/ 5171typedef void (*sqlite3_destructor_type)(void*); 5172#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5173#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5174 5175/* 5176** CAPI3REF: Setting The Result Of An SQL Function 5177** METHOD: sqlite3_context 5178** 5179** These routines are used by the xFunc or xFinal callbacks that 5180** implement SQL functions and aggregates. See 5181** [sqlite3_create_function()] and [sqlite3_create_function16()] 5182** for additional information. 5183** 5184** These functions work very much like the [parameter binding] family of 5185** functions used to bind values to host parameters in prepared statements. 5186** Refer to the [SQL parameter] documentation for additional information. 5187** 5188** ^The sqlite3_result_blob() interface sets the result from 5189** an application-defined function to be the BLOB whose content is pointed 5190** to by the second parameter and which is N bytes long where N is the 5191** third parameter. 5192** 5193** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5194** interfaces set the result of the application-defined function to be 5195** a BLOB containing all zero bytes and N bytes in size. 5196** 5197** ^The sqlite3_result_double() interface sets the result from 5198** an application-defined function to be a floating point value specified 5199** by its 2nd argument. 5200** 5201** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5202** cause the implemented SQL function to throw an exception. 5203** ^SQLite uses the string pointed to by the 5204** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5205** as the text of an error message. ^SQLite interprets the error 5206** message string from sqlite3_result_error() as UTF-8. ^SQLite 5207** interprets the string from sqlite3_result_error16() as UTF-16 in native 5208** byte order. ^If the third parameter to sqlite3_result_error() 5209** or sqlite3_result_error16() is negative then SQLite takes as the error 5210** message all text up through the first zero character. 5211** ^If the third parameter to sqlite3_result_error() or 5212** sqlite3_result_error16() is non-negative then SQLite takes that many 5213** bytes (not characters) from the 2nd parameter as the error message. 5214** ^The sqlite3_result_error() and sqlite3_result_error16() 5215** routines make a private copy of the error message text before 5216** they return. Hence, the calling function can deallocate or 5217** modify the text after they return without harm. 5218** ^The sqlite3_result_error_code() function changes the error code 5219** returned by SQLite as a result of an error in a function. ^By default, 5220** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5221** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5222** 5223** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5224** error indicating that a string or BLOB is too long to represent. 5225** 5226** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5227** error indicating that a memory allocation failed. 5228** 5229** ^The sqlite3_result_int() interface sets the return value 5230** of the application-defined function to be the 32-bit signed integer 5231** value given in the 2nd argument. 5232** ^The sqlite3_result_int64() interface sets the return value 5233** of the application-defined function to be the 64-bit signed integer 5234** value given in the 2nd argument. 5235** 5236** ^The sqlite3_result_null() interface sets the return value 5237** of the application-defined function to be NULL. 5238** 5239** ^The sqlite3_result_text(), sqlite3_result_text16(), 5240** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5241** set the return value of the application-defined function to be 5242** a text string which is represented as UTF-8, UTF-16 native byte order, 5243** UTF-16 little endian, or UTF-16 big endian, respectively. 5244** ^The sqlite3_result_text64() interface sets the return value of an 5245** application-defined function to be a text string in an encoding 5246** specified by the fifth (and last) parameter, which must be one 5247** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5248** ^SQLite takes the text result from the application from 5249** the 2nd parameter of the sqlite3_result_text* interfaces. 5250** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5251** is negative, then SQLite takes result text from the 2nd parameter 5252** through the first zero character. 5253** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5254** is non-negative, then as many bytes (not characters) of the text 5255** pointed to by the 2nd parameter are taken as the application-defined 5256** function result. If the 3rd parameter is non-negative, then it 5257** must be the byte offset into the string where the NUL terminator would 5258** appear if the string where NUL terminated. If any NUL characters occur 5259** in the string at a byte offset that is less than the value of the 3rd 5260** parameter, then the resulting string will contain embedded NULs and the 5261** result of expressions operating on strings with embedded NULs is undefined. 5262** ^If the 4th parameter to the sqlite3_result_text* interfaces 5263** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5264** function as the destructor on the text or BLOB result when it has 5265** finished using that result. 5266** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5267** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5268** assumes that the text or BLOB result is in constant space and does not 5269** copy the content of the parameter nor call a destructor on the content 5270** when it has finished using that result. 5271** ^If the 4th parameter to the sqlite3_result_text* interfaces 5272** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5273** then SQLite makes a copy of the result into space obtained 5274** from [sqlite3_malloc()] before it returns. 5275** 5276** ^The sqlite3_result_value() interface sets the result of 5277** the application-defined function to be a copy of the 5278** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5279** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5280** so that the [sqlite3_value] specified in the parameter may change or 5281** be deallocated after sqlite3_result_value() returns without harm. 5282** ^A [protected sqlite3_value] object may always be used where an 5283** [unprotected sqlite3_value] object is required, so either 5284** kind of [sqlite3_value] object can be used with this interface. 5285** 5286** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5287** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5288** also associates the host-language pointer P or type T with that 5289** NULL value such that the pointer can be retrieved within an 5290** [application-defined SQL function] using [sqlite3_value_pointer()]. 5291** ^If the D parameter is not NULL, then it is a pointer to a destructor 5292** for the P parameter. ^SQLite invokes D with P as its only argument 5293** when SQLite is finished with P. The T parameter should be a static 5294** string and preferably a string literal. The sqlite3_result_pointer() 5295** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5296** 5297** If these routines are called from within the different thread 5298** than the one containing the application-defined function that received 5299** the [sqlite3_context] pointer, the results are undefined. 5300*/ 5301void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5302void sqlite3_result_blob64(sqlite3_context*,const void*, 5303 sqlite3_uint64,void(*)(void*)); 5304void sqlite3_result_double(sqlite3_context*, double); 5305void sqlite3_result_error(sqlite3_context*, const char*, int); 5306void sqlite3_result_error16(sqlite3_context*, const void*, int); 5307void sqlite3_result_error_toobig(sqlite3_context*); 5308void sqlite3_result_error_nomem(sqlite3_context*); 5309void sqlite3_result_error_code(sqlite3_context*, int); 5310void sqlite3_result_int(sqlite3_context*, int); 5311void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5312void sqlite3_result_null(sqlite3_context*); 5313void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5314void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5315 void(*)(void*), unsigned char encoding); 5316void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5317void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5318void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5319void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5320void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5321void sqlite3_result_zeroblob(sqlite3_context*, int n); 5322int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5323 5324 5325/* 5326** CAPI3REF: Setting The Subtype Of An SQL Function 5327** METHOD: sqlite3_context 5328** 5329** The sqlite3_result_subtype(C,T) function causes the subtype of 5330** the result from the [application-defined SQL function] with 5331** [sqlite3_context] C to be the value T. Only the lower 8 bits 5332** of the subtype T are preserved in current versions of SQLite; 5333** higher order bits are discarded. 5334** The number of subtype bytes preserved by SQLite might increase 5335** in future releases of SQLite. 5336*/ 5337void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5338 5339/* 5340** CAPI3REF: Define New Collating Sequences 5341** METHOD: sqlite3 5342** 5343** ^These functions add, remove, or modify a [collation] associated 5344** with the [database connection] specified as the first argument. 5345** 5346** ^The name of the collation is a UTF-8 string 5347** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5348** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5349** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5350** considered to be the same name. 5351** 5352** ^(The third argument (eTextRep) must be one of the constants: 5353** <ul> 5354** <li> [SQLITE_UTF8], 5355** <li> [SQLITE_UTF16LE], 5356** <li> [SQLITE_UTF16BE], 5357** <li> [SQLITE_UTF16], or 5358** <li> [SQLITE_UTF16_ALIGNED]. 5359** </ul>)^ 5360** ^The eTextRep argument determines the encoding of strings passed 5361** to the collating function callback, xCallback. 5362** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5363** force strings to be UTF16 with native byte order. 5364** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5365** on an even byte address. 5366** 5367** ^The fourth argument, pArg, is an application data pointer that is passed 5368** through as the first argument to the collating function callback. 5369** 5370** ^The fifth argument, xCallback, is a pointer to the collating function. 5371** ^Multiple collating functions can be registered using the same name but 5372** with different eTextRep parameters and SQLite will use whichever 5373** function requires the least amount of data transformation. 5374** ^If the xCallback argument is NULL then the collating function is 5375** deleted. ^When all collating functions having the same name are deleted, 5376** that collation is no longer usable. 5377** 5378** ^The collating function callback is invoked with a copy of the pArg 5379** application data pointer and with two strings in the encoding specified 5380** by the eTextRep argument. The collating function must return an 5381** integer that is negative, zero, or positive 5382** if the first string is less than, equal to, or greater than the second, 5383** respectively. A collating function must always return the same answer 5384** given the same inputs. If two or more collating functions are registered 5385** to the same collation name (using different eTextRep values) then all 5386** must give an equivalent answer when invoked with equivalent strings. 5387** The collating function must obey the following properties for all 5388** strings A, B, and C: 5389** 5390** <ol> 5391** <li> If A==B then B==A. 5392** <li> If A==B and B==C then A==C. 5393** <li> If A<B THEN B>A. 5394** <li> If A<B and B<C then A<C. 5395** </ol> 5396** 5397** If a collating function fails any of the above constraints and that 5398** collating function is registered and used, then the behavior of SQLite 5399** is undefined. 5400** 5401** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5402** with the addition that the xDestroy callback is invoked on pArg when 5403** the collating function is deleted. 5404** ^Collating functions are deleted when they are overridden by later 5405** calls to the collation creation functions or when the 5406** [database connection] is closed using [sqlite3_close()]. 5407** 5408** ^The xDestroy callback is <u>not</u> called if the 5409** sqlite3_create_collation_v2() function fails. Applications that invoke 5410** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5411** check the return code and dispose of the application data pointer 5412** themselves rather than expecting SQLite to deal with it for them. 5413** This is different from every other SQLite interface. The inconsistency 5414** is unfortunate but cannot be changed without breaking backwards 5415** compatibility. 5416** 5417** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5418*/ 5419int sqlite3_create_collation( 5420 sqlite3*, 5421 const char *zName, 5422 int eTextRep, 5423 void *pArg, 5424 int(*xCompare)(void*,int,const void*,int,const void*) 5425); 5426int sqlite3_create_collation_v2( 5427 sqlite3*, 5428 const char *zName, 5429 int eTextRep, 5430 void *pArg, 5431 int(*xCompare)(void*,int,const void*,int,const void*), 5432 void(*xDestroy)(void*) 5433); 5434int sqlite3_create_collation16( 5435 sqlite3*, 5436 const void *zName, 5437 int eTextRep, 5438 void *pArg, 5439 int(*xCompare)(void*,int,const void*,int,const void*) 5440); 5441 5442/* 5443** CAPI3REF: Collation Needed Callbacks 5444** METHOD: sqlite3 5445** 5446** ^To avoid having to register all collation sequences before a database 5447** can be used, a single callback function may be registered with the 5448** [database connection] to be invoked whenever an undefined collation 5449** sequence is required. 5450** 5451** ^If the function is registered using the sqlite3_collation_needed() API, 5452** then it is passed the names of undefined collation sequences as strings 5453** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5454** the names are passed as UTF-16 in machine native byte order. 5455** ^A call to either function replaces the existing collation-needed callback. 5456** 5457** ^(When the callback is invoked, the first argument passed is a copy 5458** of the second argument to sqlite3_collation_needed() or 5459** sqlite3_collation_needed16(). The second argument is the database 5460** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5461** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5462** sequence function required. The fourth parameter is the name of the 5463** required collation sequence.)^ 5464** 5465** The callback function should register the desired collation using 5466** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5467** [sqlite3_create_collation_v2()]. 5468*/ 5469int sqlite3_collation_needed( 5470 sqlite3*, 5471 void*, 5472 void(*)(void*,sqlite3*,int eTextRep,const char*) 5473); 5474int sqlite3_collation_needed16( 5475 sqlite3*, 5476 void*, 5477 void(*)(void*,sqlite3*,int eTextRep,const void*) 5478); 5479 5480#ifdef SQLITE_HAS_CODEC 5481/* 5482** Specify the key for an encrypted database. This routine should be 5483** called right after sqlite3_open(). 5484** 5485** The code to implement this API is not available in the public release 5486** of SQLite. 5487*/ 5488int sqlite3_key( 5489 sqlite3 *db, /* Database to be rekeyed */ 5490 const void *pKey, int nKey /* The key */ 5491); 5492int sqlite3_key_v2( 5493 sqlite3 *db, /* Database to be rekeyed */ 5494 const char *zDbName, /* Name of the database */ 5495 const void *pKey, int nKey /* The key */ 5496); 5497 5498/* 5499** Change the key on an open database. If the current database is not 5500** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 5501** database is decrypted. 5502** 5503** The code to implement this API is not available in the public release 5504** of SQLite. 5505*/ 5506int sqlite3_rekey( 5507 sqlite3 *db, /* Database to be rekeyed */ 5508 const void *pKey, int nKey /* The new key */ 5509); 5510int sqlite3_rekey_v2( 5511 sqlite3 *db, /* Database to be rekeyed */ 5512 const char *zDbName, /* Name of the database */ 5513 const void *pKey, int nKey /* The new key */ 5514); 5515 5516/* 5517** Specify the activation key for a SEE database. Unless 5518** activated, none of the SEE routines will work. 5519*/ 5520void sqlite3_activate_see( 5521 const char *zPassPhrase /* Activation phrase */ 5522); 5523#endif 5524 5525#ifdef SQLITE_ENABLE_CEROD 5526/* 5527** Specify the activation key for a CEROD database. Unless 5528** activated, none of the CEROD routines will work. 5529*/ 5530void sqlite3_activate_cerod( 5531 const char *zPassPhrase /* Activation phrase */ 5532); 5533#endif 5534 5535/* 5536** CAPI3REF: Suspend Execution For A Short Time 5537** 5538** The sqlite3_sleep() function causes the current thread to suspend execution 5539** for at least a number of milliseconds specified in its parameter. 5540** 5541** If the operating system does not support sleep requests with 5542** millisecond time resolution, then the time will be rounded up to 5543** the nearest second. The number of milliseconds of sleep actually 5544** requested from the operating system is returned. 5545** 5546** ^SQLite implements this interface by calling the xSleep() 5547** method of the default [sqlite3_vfs] object. If the xSleep() method 5548** of the default VFS is not implemented correctly, or not implemented at 5549** all, then the behavior of sqlite3_sleep() may deviate from the description 5550** in the previous paragraphs. 5551*/ 5552int sqlite3_sleep(int); 5553 5554/* 5555** CAPI3REF: Name Of The Folder Holding Temporary Files 5556** 5557** ^(If this global variable is made to point to a string which is 5558** the name of a folder (a.k.a. directory), then all temporary files 5559** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5560** will be placed in that directory.)^ ^If this variable 5561** is a NULL pointer, then SQLite performs a search for an appropriate 5562** temporary file directory. 5563** 5564** Applications are strongly discouraged from using this global variable. 5565** It is required to set a temporary folder on Windows Runtime (WinRT). 5566** But for all other platforms, it is highly recommended that applications 5567** neither read nor write this variable. This global variable is a relic 5568** that exists for backwards compatibility of legacy applications and should 5569** be avoided in new projects. 5570** 5571** It is not safe to read or modify this variable in more than one 5572** thread at a time. It is not safe to read or modify this variable 5573** if a [database connection] is being used at the same time in a separate 5574** thread. 5575** It is intended that this variable be set once 5576** as part of process initialization and before any SQLite interface 5577** routines have been called and that this variable remain unchanged 5578** thereafter. 5579** 5580** ^The [temp_store_directory pragma] may modify this variable and cause 5581** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5582** the [temp_store_directory pragma] always assumes that any string 5583** that this variable points to is held in memory obtained from 5584** [sqlite3_malloc] and the pragma may attempt to free that memory 5585** using [sqlite3_free]. 5586** Hence, if this variable is modified directly, either it should be 5587** made NULL or made to point to memory obtained from [sqlite3_malloc] 5588** or else the use of the [temp_store_directory pragma] should be avoided. 5589** Except when requested by the [temp_store_directory pragma], SQLite 5590** does not free the memory that sqlite3_temp_directory points to. If 5591** the application wants that memory to be freed, it must do 5592** so itself, taking care to only do so after all [database connection] 5593** objects have been destroyed. 5594** 5595** <b>Note to Windows Runtime users:</b> The temporary directory must be set 5596** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 5597** features that require the use of temporary files may fail. Here is an 5598** example of how to do this using C++ with the Windows Runtime: 5599** 5600** <blockquote><pre> 5601** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 5602** TemporaryFolder->Path->Data(); 5603** char zPathBuf[MAX_PATH + 1]; 5604** memset(zPathBuf, 0, sizeof(zPathBuf)); 5605** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 5606** NULL, NULL); 5607** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 5608** </pre></blockquote> 5609*/ 5610SQLITE_EXTERN char *sqlite3_temp_directory; 5611 5612/* 5613** CAPI3REF: Name Of The Folder Holding Database Files 5614** 5615** ^(If this global variable is made to point to a string which is 5616** the name of a folder (a.k.a. directory), then all database files 5617** specified with a relative pathname and created or accessed by 5618** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 5619** to be relative to that directory.)^ ^If this variable is a NULL 5620** pointer, then SQLite assumes that all database files specified 5621** with a relative pathname are relative to the current directory 5622** for the process. Only the windows VFS makes use of this global 5623** variable; it is ignored by the unix VFS. 5624** 5625** Changing the value of this variable while a database connection is 5626** open can result in a corrupt database. 5627** 5628** It is not safe to read or modify this variable in more than one 5629** thread at a time. It is not safe to read or modify this variable 5630** if a [database connection] is being used at the same time in a separate 5631** thread. 5632** It is intended that this variable be set once 5633** as part of process initialization and before any SQLite interface 5634** routines have been called and that this variable remain unchanged 5635** thereafter. 5636** 5637** ^The [data_store_directory pragma] may modify this variable and cause 5638** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5639** the [data_store_directory pragma] always assumes that any string 5640** that this variable points to is held in memory obtained from 5641** [sqlite3_malloc] and the pragma may attempt to free that memory 5642** using [sqlite3_free]. 5643** Hence, if this variable is modified directly, either it should be 5644** made NULL or made to point to memory obtained from [sqlite3_malloc] 5645** or else the use of the [data_store_directory pragma] should be avoided. 5646*/ 5647SQLITE_EXTERN char *sqlite3_data_directory; 5648 5649/* 5650** CAPI3REF: Win32 Specific Interface 5651** 5652** These interfaces are available only on Windows. The 5653** [sqlite3_win32_set_directory] interface is used to set the value associated 5654** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to 5655** zValue, depending on the value of the type parameter. The zValue parameter 5656** should be NULL to cause the previous value to be freed via [sqlite3_free]; 5657** a non-NULL value will be copied into memory obtained from [sqlite3_malloc] 5658** prior to being used. The [sqlite3_win32_set_directory] interface returns 5659** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported, 5660** or [SQLITE_NOMEM] if memory could not be allocated. The value of the 5661** [sqlite3_data_directory] variable is intended to act as a replacement for 5662** the current directory on the sub-platforms of Win32 where that concept is 5663** not present, e.g. WinRT and UWP. The [sqlite3_win32_set_directory8] and 5664** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the 5665** sqlite3_win32_set_directory interface except the string parameter must be 5666** UTF-8 or UTF-16, respectively. 5667*/ 5668int sqlite3_win32_set_directory( 5669 unsigned long type, /* Identifier for directory being set or reset */ 5670 void *zValue /* New value for directory being set or reset */ 5671); 5672int sqlite3_win32_set_directory8(unsigned long type, const char *zValue); 5673int sqlite3_win32_set_directory16(unsigned long type, const void *zValue); 5674 5675/* 5676** CAPI3REF: Win32 Directory Types 5677** 5678** These macros are only available on Windows. They define the allowed values 5679** for the type argument to the [sqlite3_win32_set_directory] interface. 5680*/ 5681#define SQLITE_WIN32_DATA_DIRECTORY_TYPE 1 5682#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE 2 5683 5684/* 5685** CAPI3REF: Test For Auto-Commit Mode 5686** KEYWORDS: {autocommit mode} 5687** METHOD: sqlite3 5688** 5689** ^The sqlite3_get_autocommit() interface returns non-zero or 5690** zero if the given database connection is or is not in autocommit mode, 5691** respectively. ^Autocommit mode is on by default. 5692** ^Autocommit mode is disabled by a [BEGIN] statement. 5693** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5694** 5695** If certain kinds of errors occur on a statement within a multi-statement 5696** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5697** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5698** transaction might be rolled back automatically. The only way to 5699** find out whether SQLite automatically rolled back the transaction after 5700** an error is to use this function. 5701** 5702** If another thread changes the autocommit status of the database 5703** connection while this routine is running, then the return value 5704** is undefined. 5705*/ 5706int sqlite3_get_autocommit(sqlite3*); 5707 5708/* 5709** CAPI3REF: Find The Database Handle Of A Prepared Statement 5710** METHOD: sqlite3_stmt 5711** 5712** ^The sqlite3_db_handle interface returns the [database connection] handle 5713** to which a [prepared statement] belongs. ^The [database connection] 5714** returned by sqlite3_db_handle is the same [database connection] 5715** that was the first argument 5716** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5717** create the statement in the first place. 5718*/ 5719sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5720 5721/* 5722** CAPI3REF: Return The Filename For A Database Connection 5723** METHOD: sqlite3 5724** 5725** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5726** associated with database N of connection D. ^The main database file 5727** has the name "main". If there is no attached database N on the database 5728** connection D, or if database N is a temporary or in-memory database, then 5729** a NULL pointer is returned. 5730** 5731** ^The filename returned by this function is the output of the 5732** xFullPathname method of the [VFS]. ^In other words, the filename 5733** will be an absolute pathname, even if the filename used 5734** to open the database originally was a URI or relative pathname. 5735*/ 5736const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5737 5738/* 5739** CAPI3REF: Determine if a database is read-only 5740** METHOD: sqlite3 5741** 5742** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5743** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5744** the name of a database on connection D. 5745*/ 5746int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5747 5748/* 5749** CAPI3REF: Find the next prepared statement 5750** METHOD: sqlite3 5751** 5752** ^This interface returns a pointer to the next [prepared statement] after 5753** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5754** then this interface returns a pointer to the first prepared statement 5755** associated with the database connection pDb. ^If no prepared statement 5756** satisfies the conditions of this routine, it returns NULL. 5757** 5758** The [database connection] pointer D in a call to 5759** [sqlite3_next_stmt(D,S)] must refer to an open database 5760** connection and in particular must not be a NULL pointer. 5761*/ 5762sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5763 5764/* 5765** CAPI3REF: Commit And Rollback Notification Callbacks 5766** METHOD: sqlite3 5767** 5768** ^The sqlite3_commit_hook() interface registers a callback 5769** function to be invoked whenever a transaction is [COMMIT | committed]. 5770** ^Any callback set by a previous call to sqlite3_commit_hook() 5771** for the same database connection is overridden. 5772** ^The sqlite3_rollback_hook() interface registers a callback 5773** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5774** ^Any callback set by a previous call to sqlite3_rollback_hook() 5775** for the same database connection is overridden. 5776** ^The pArg argument is passed through to the callback. 5777** ^If the callback on a commit hook function returns non-zero, 5778** then the commit is converted into a rollback. 5779** 5780** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5781** return the P argument from the previous call of the same function 5782** on the same [database connection] D, or NULL for 5783** the first call for each function on D. 5784** 5785** The commit and rollback hook callbacks are not reentrant. 5786** The callback implementation must not do anything that will modify 5787** the database connection that invoked the callback. Any actions 5788** to modify the database connection must be deferred until after the 5789** completion of the [sqlite3_step()] call that triggered the commit 5790** or rollback hook in the first place. 5791** Note that running any other SQL statements, including SELECT statements, 5792** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5793** the database connections for the meaning of "modify" in this paragraph. 5794** 5795** ^Registering a NULL function disables the callback. 5796** 5797** ^When the commit hook callback routine returns zero, the [COMMIT] 5798** operation is allowed to continue normally. ^If the commit hook 5799** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5800** ^The rollback hook is invoked on a rollback that results from a commit 5801** hook returning non-zero, just as it would be with any other rollback. 5802** 5803** ^For the purposes of this API, a transaction is said to have been 5804** rolled back if an explicit "ROLLBACK" statement is executed, or 5805** an error or constraint causes an implicit rollback to occur. 5806** ^The rollback callback is not invoked if a transaction is 5807** automatically rolled back because the database connection is closed. 5808** 5809** See also the [sqlite3_update_hook()] interface. 5810*/ 5811void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5812void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5813 5814/* 5815** CAPI3REF: Data Change Notification Callbacks 5816** METHOD: sqlite3 5817** 5818** ^The sqlite3_update_hook() interface registers a callback function 5819** with the [database connection] identified by the first argument 5820** to be invoked whenever a row is updated, inserted or deleted in 5821** a [rowid table]. 5822** ^Any callback set by a previous call to this function 5823** for the same database connection is overridden. 5824** 5825** ^The second argument is a pointer to the function to invoke when a 5826** row is updated, inserted or deleted in a rowid table. 5827** ^The first argument to the callback is a copy of the third argument 5828** to sqlite3_update_hook(). 5829** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5830** or [SQLITE_UPDATE], depending on the operation that caused the callback 5831** to be invoked. 5832** ^The third and fourth arguments to the callback contain pointers to the 5833** database and table name containing the affected row. 5834** ^The final callback parameter is the [rowid] of the row. 5835** ^In the case of an update, this is the [rowid] after the update takes place. 5836** 5837** ^(The update hook is not invoked when internal system tables are 5838** modified (i.e. sqlite_master and sqlite_sequence).)^ 5839** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5840** 5841** ^In the current implementation, the update hook 5842** is not invoked when conflicting rows are deleted because of an 5843** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5844** invoked when rows are deleted using the [truncate optimization]. 5845** The exceptions defined in this paragraph might change in a future 5846** release of SQLite. 5847** 5848** The update hook implementation must not do anything that will modify 5849** the database connection that invoked the update hook. Any actions 5850** to modify the database connection must be deferred until after the 5851** completion of the [sqlite3_step()] call that triggered the update hook. 5852** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5853** database connections for the meaning of "modify" in this paragraph. 5854** 5855** ^The sqlite3_update_hook(D,C,P) function 5856** returns the P argument from the previous call 5857** on the same [database connection] D, or NULL for 5858** the first call on D. 5859** 5860** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 5861** and [sqlite3_preupdate_hook()] interfaces. 5862*/ 5863void *sqlite3_update_hook( 5864 sqlite3*, 5865 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5866 void* 5867); 5868 5869/* 5870** CAPI3REF: Enable Or Disable Shared Pager Cache 5871** 5872** ^(This routine enables or disables the sharing of the database cache 5873** and schema data structures between [database connection | connections] 5874** to the same database. Sharing is enabled if the argument is true 5875** and disabled if the argument is false.)^ 5876** 5877** ^Cache sharing is enabled and disabled for an entire process. 5878** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 5879** In prior versions of SQLite, 5880** sharing was enabled or disabled for each thread separately. 5881** 5882** ^(The cache sharing mode set by this interface effects all subsequent 5883** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5884** Existing database connections continue use the sharing mode 5885** that was in effect at the time they were opened.)^ 5886** 5887** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5888** successfully. An [error code] is returned otherwise.)^ 5889** 5890** ^Shared cache is disabled by default. But this might change in 5891** future releases of SQLite. Applications that care about shared 5892** cache setting should set it explicitly. 5893** 5894** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5895** and will always return SQLITE_MISUSE. On those systems, 5896** shared cache mode should be enabled per-database connection via 5897** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5898** 5899** This interface is threadsafe on processors where writing a 5900** 32-bit integer is atomic. 5901** 5902** See Also: [SQLite Shared-Cache Mode] 5903*/ 5904int sqlite3_enable_shared_cache(int); 5905 5906/* 5907** CAPI3REF: Attempt To Free Heap Memory 5908** 5909** ^The sqlite3_release_memory() interface attempts to free N bytes 5910** of heap memory by deallocating non-essential memory allocations 5911** held by the database library. Memory used to cache database 5912** pages to improve performance is an example of non-essential memory. 5913** ^sqlite3_release_memory() returns the number of bytes actually freed, 5914** which might be more or less than the amount requested. 5915** ^The sqlite3_release_memory() routine is a no-op returning zero 5916** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5917** 5918** See also: [sqlite3_db_release_memory()] 5919*/ 5920int sqlite3_release_memory(int); 5921 5922/* 5923** CAPI3REF: Free Memory Used By A Database Connection 5924** METHOD: sqlite3 5925** 5926** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5927** memory as possible from database connection D. Unlike the 5928** [sqlite3_release_memory()] interface, this interface is in effect even 5929** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5930** omitted. 5931** 5932** See also: [sqlite3_release_memory()] 5933*/ 5934int sqlite3_db_release_memory(sqlite3*); 5935 5936/* 5937** CAPI3REF: Impose A Limit On Heap Size 5938** 5939** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5940** soft limit on the amount of heap memory that may be allocated by SQLite. 5941** ^SQLite strives to keep heap memory utilization below the soft heap 5942** limit by reducing the number of pages held in the page cache 5943** as heap memory usages approaches the limit. 5944** ^The soft heap limit is "soft" because even though SQLite strives to stay 5945** below the limit, it will exceed the limit rather than generate 5946** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5947** is advisory only. 5948** 5949** ^The return value from sqlite3_soft_heap_limit64() is the size of 5950** the soft heap limit prior to the call, or negative in the case of an 5951** error. ^If the argument N is negative 5952** then no change is made to the soft heap limit. Hence, the current 5953** size of the soft heap limit can be determined by invoking 5954** sqlite3_soft_heap_limit64() with a negative argument. 5955** 5956** ^If the argument N is zero then the soft heap limit is disabled. 5957** 5958** ^(The soft heap limit is not enforced in the current implementation 5959** if one or more of following conditions are true: 5960** 5961** <ul> 5962** <li> The soft heap limit is set to zero. 5963** <li> Memory accounting is disabled using a combination of the 5964** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5965** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5966** <li> An alternative page cache implementation is specified using 5967** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5968** <li> The page cache allocates from its own memory pool supplied 5969** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5970** from the heap. 5971** </ul>)^ 5972** 5973** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]), 5974** the soft heap limit is enforced 5975** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5976** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5977** the soft heap limit is enforced on every memory allocation. Without 5978** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5979** when memory is allocated by the page cache. Testing suggests that because 5980** the page cache is the predominate memory user in SQLite, most 5981** applications will achieve adequate soft heap limit enforcement without 5982** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5983** 5984** The circumstances under which SQLite will enforce the soft heap limit may 5985** changes in future releases of SQLite. 5986*/ 5987sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5988 5989/* 5990** CAPI3REF: Deprecated Soft Heap Limit Interface 5991** DEPRECATED 5992** 5993** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5994** interface. This routine is provided for historical compatibility 5995** only. All new applications should use the 5996** [sqlite3_soft_heap_limit64()] interface rather than this one. 5997*/ 5998SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5999 6000 6001/* 6002** CAPI3REF: Extract Metadata About A Column Of A Table 6003** METHOD: sqlite3 6004** 6005** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 6006** information about column C of table T in database D 6007** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 6008** interface returns SQLITE_OK and fills in the non-NULL pointers in 6009** the final five arguments with appropriate values if the specified 6010** column exists. ^The sqlite3_table_column_metadata() interface returns 6011** SQLITE_ERROR and if the specified column does not exist. 6012** ^If the column-name parameter to sqlite3_table_column_metadata() is a 6013** NULL pointer, then this routine simply checks for the existence of the 6014** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 6015** does not. If the table name parameter T in a call to 6016** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 6017** undefined behavior. 6018** 6019** ^The column is identified by the second, third and fourth parameters to 6020** this function. ^(The second parameter is either the name of the database 6021** (i.e. "main", "temp", or an attached database) containing the specified 6022** table or NULL.)^ ^If it is NULL, then all attached databases are searched 6023** for the table using the same algorithm used by the database engine to 6024** resolve unqualified table references. 6025** 6026** ^The third and fourth parameters to this function are the table and column 6027** name of the desired column, respectively. 6028** 6029** ^Metadata is returned by writing to the memory locations passed as the 5th 6030** and subsequent parameters to this function. ^Any of these arguments may be 6031** NULL, in which case the corresponding element of metadata is omitted. 6032** 6033** ^(<blockquote> 6034** <table border="1"> 6035** <tr><th> Parameter <th> Output<br>Type <th> Description 6036** 6037** <tr><td> 5th <td> const char* <td> Data type 6038** <tr><td> 6th <td> const char* <td> Name of default collation sequence 6039** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 6040** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 6041** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 6042** </table> 6043** </blockquote>)^ 6044** 6045** ^The memory pointed to by the character pointers returned for the 6046** declaration type and collation sequence is valid until the next 6047** call to any SQLite API function. 6048** 6049** ^If the specified table is actually a view, an [error code] is returned. 6050** 6051** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 6052** is not a [WITHOUT ROWID] table and an 6053** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 6054** parameters are set for the explicitly declared column. ^(If there is no 6055** [INTEGER PRIMARY KEY] column, then the outputs 6056** for the [rowid] are set as follows: 6057** 6058** <pre> 6059** data type: "INTEGER" 6060** collation sequence: "BINARY" 6061** not null: 0 6062** primary key: 1 6063** auto increment: 0 6064** </pre>)^ 6065** 6066** ^This function causes all database schemas to be read from disk and 6067** parsed, if that has not already been done, and returns an error if 6068** any errors are encountered while loading the schema. 6069*/ 6070int sqlite3_table_column_metadata( 6071 sqlite3 *db, /* Connection handle */ 6072 const char *zDbName, /* Database name or NULL */ 6073 const char *zTableName, /* Table name */ 6074 const char *zColumnName, /* Column name */ 6075 char const **pzDataType, /* OUTPUT: Declared data type */ 6076 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 6077 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 6078 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 6079 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 6080); 6081 6082/* 6083** CAPI3REF: Load An Extension 6084** METHOD: sqlite3 6085** 6086** ^This interface loads an SQLite extension library from the named file. 6087** 6088** ^The sqlite3_load_extension() interface attempts to load an 6089** [SQLite extension] library contained in the file zFile. If 6090** the file cannot be loaded directly, attempts are made to load 6091** with various operating-system specific extensions added. 6092** So for example, if "samplelib" cannot be loaded, then names like 6093** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 6094** be tried also. 6095** 6096** ^The entry point is zProc. 6097** ^(zProc may be 0, in which case SQLite will try to come up with an 6098** entry point name on its own. It first tries "sqlite3_extension_init". 6099** If that does not work, it constructs a name "sqlite3_X_init" where the 6100** X is consists of the lower-case equivalent of all ASCII alphabetic 6101** characters in the filename from the last "/" to the first following 6102** "." and omitting any initial "lib".)^ 6103** ^The sqlite3_load_extension() interface returns 6104** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 6105** ^If an error occurs and pzErrMsg is not 0, then the 6106** [sqlite3_load_extension()] interface shall attempt to 6107** fill *pzErrMsg with error message text stored in memory 6108** obtained from [sqlite3_malloc()]. The calling function 6109** should free this memory by calling [sqlite3_free()]. 6110** 6111** ^Extension loading must be enabled using 6112** [sqlite3_enable_load_extension()] or 6113** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 6114** prior to calling this API, 6115** otherwise an error will be returned. 6116** 6117** <b>Security warning:</b> It is recommended that the 6118** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 6119** interface. The use of the [sqlite3_enable_load_extension()] interface 6120** should be avoided. This will keep the SQL function [load_extension()] 6121** disabled and prevent SQL injections from giving attackers 6122** access to extension loading capabilities. 6123** 6124** See also the [load_extension() SQL function]. 6125*/ 6126int sqlite3_load_extension( 6127 sqlite3 *db, /* Load the extension into this database connection */ 6128 const char *zFile, /* Name of the shared library containing extension */ 6129 const char *zProc, /* Entry point. Derived from zFile if 0 */ 6130 char **pzErrMsg /* Put error message here if not 0 */ 6131); 6132 6133/* 6134** CAPI3REF: Enable Or Disable Extension Loading 6135** METHOD: sqlite3 6136** 6137** ^So as not to open security holes in older applications that are 6138** unprepared to deal with [extension loading], and as a means of disabling 6139** [extension loading] while evaluating user-entered SQL, the following API 6140** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 6141** 6142** ^Extension loading is off by default. 6143** ^Call the sqlite3_enable_load_extension() routine with onoff==1 6144** to turn extension loading on and call it with onoff==0 to turn 6145** it back off again. 6146** 6147** ^This interface enables or disables both the C-API 6148** [sqlite3_load_extension()] and the SQL function [load_extension()]. 6149** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 6150** to enable or disable only the C-API.)^ 6151** 6152** <b>Security warning:</b> It is recommended that extension loading 6153** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 6154** rather than this interface, so the [load_extension()] SQL function 6155** remains disabled. This will prevent SQL injections from giving attackers 6156** access to extension loading capabilities. 6157*/ 6158int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 6159 6160/* 6161** CAPI3REF: Automatically Load Statically Linked Extensions 6162** 6163** ^This interface causes the xEntryPoint() function to be invoked for 6164** each new [database connection] that is created. The idea here is that 6165** xEntryPoint() is the entry point for a statically linked [SQLite extension] 6166** that is to be automatically loaded into all new database connections. 6167** 6168** ^(Even though the function prototype shows that xEntryPoint() takes 6169** no arguments and returns void, SQLite invokes xEntryPoint() with three 6170** arguments and expects an integer result as if the signature of the 6171** entry point where as follows: 6172** 6173** <blockquote><pre> 6174** int xEntryPoint( 6175** sqlite3 *db, 6176** const char **pzErrMsg, 6177** const struct sqlite3_api_routines *pThunk 6178** ); 6179** </pre></blockquote>)^ 6180** 6181** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 6182** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 6183** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 6184** is NULL before calling the xEntryPoint(). ^SQLite will invoke 6185** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 6186** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 6187** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6188** 6189** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6190** on the list of automatic extensions is a harmless no-op. ^No entry point 6191** will be called more than once for each database connection that is opened. 6192** 6193** See also: [sqlite3_reset_auto_extension()] 6194** and [sqlite3_cancel_auto_extension()] 6195*/ 6196int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6197 6198/* 6199** CAPI3REF: Cancel Automatic Extension Loading 6200** 6201** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6202** initialization routine X that was registered using a prior call to 6203** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6204** routine returns 1 if initialization routine X was successfully 6205** unregistered and it returns 0 if X was not on the list of initialization 6206** routines. 6207*/ 6208int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6209 6210/* 6211** CAPI3REF: Reset Automatic Extension Loading 6212** 6213** ^This interface disables all automatic extensions previously 6214** registered using [sqlite3_auto_extension()]. 6215*/ 6216void sqlite3_reset_auto_extension(void); 6217 6218/* 6219** The interface to the virtual-table mechanism is currently considered 6220** to be experimental. The interface might change in incompatible ways. 6221** If this is a problem for you, do not use the interface at this time. 6222** 6223** When the virtual-table mechanism stabilizes, we will declare the 6224** interface fixed, support it indefinitely, and remove this comment. 6225*/ 6226 6227/* 6228** Structures used by the virtual table interface 6229*/ 6230typedef struct sqlite3_vtab sqlite3_vtab; 6231typedef struct sqlite3_index_info sqlite3_index_info; 6232typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6233typedef struct sqlite3_module sqlite3_module; 6234 6235/* 6236** CAPI3REF: Virtual Table Object 6237** KEYWORDS: sqlite3_module {virtual table module} 6238** 6239** This structure, sometimes called a "virtual table module", 6240** defines the implementation of a [virtual tables]. 6241** This structure consists mostly of methods for the module. 6242** 6243** ^A virtual table module is created by filling in a persistent 6244** instance of this structure and passing a pointer to that instance 6245** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6246** ^The registration remains valid until it is replaced by a different 6247** module or until the [database connection] closes. The content 6248** of this structure must not change while it is registered with 6249** any database connection. 6250*/ 6251struct sqlite3_module { 6252 int iVersion; 6253 int (*xCreate)(sqlite3*, void *pAux, 6254 int argc, const char *const*argv, 6255 sqlite3_vtab **ppVTab, char**); 6256 int (*xConnect)(sqlite3*, void *pAux, 6257 int argc, const char *const*argv, 6258 sqlite3_vtab **ppVTab, char**); 6259 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6260 int (*xDisconnect)(sqlite3_vtab *pVTab); 6261 int (*xDestroy)(sqlite3_vtab *pVTab); 6262 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6263 int (*xClose)(sqlite3_vtab_cursor*); 6264 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6265 int argc, sqlite3_value **argv); 6266 int (*xNext)(sqlite3_vtab_cursor*); 6267 int (*xEof)(sqlite3_vtab_cursor*); 6268 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6269 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6270 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6271 int (*xBegin)(sqlite3_vtab *pVTab); 6272 int (*xSync)(sqlite3_vtab *pVTab); 6273 int (*xCommit)(sqlite3_vtab *pVTab); 6274 int (*xRollback)(sqlite3_vtab *pVTab); 6275 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6276 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6277 void **ppArg); 6278 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6279 /* The methods above are in version 1 of the sqlite_module object. Those 6280 ** below are for version 2 and greater. */ 6281 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6282 int (*xRelease)(sqlite3_vtab *pVTab, int); 6283 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6284}; 6285 6286/* 6287** CAPI3REF: Virtual Table Indexing Information 6288** KEYWORDS: sqlite3_index_info 6289** 6290** The sqlite3_index_info structure and its substructures is used as part 6291** of the [virtual table] interface to 6292** pass information into and receive the reply from the [xBestIndex] 6293** method of a [virtual table module]. The fields under **Inputs** are the 6294** inputs to xBestIndex and are read-only. xBestIndex inserts its 6295** results into the **Outputs** fields. 6296** 6297** ^(The aConstraint[] array records WHERE clause constraints of the form: 6298** 6299** <blockquote>column OP expr</blockquote> 6300** 6301** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6302** stored in aConstraint[].op using one of the 6303** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6304** ^(The index of the column is stored in 6305** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6306** expr on the right-hand side can be evaluated (and thus the constraint 6307** is usable) and false if it cannot.)^ 6308** 6309** ^The optimizer automatically inverts terms of the form "expr OP column" 6310** and makes other simplifications to the WHERE clause in an attempt to 6311** get as many WHERE clause terms into the form shown above as possible. 6312** ^The aConstraint[] array only reports WHERE clause terms that are 6313** relevant to the particular virtual table being queried. 6314** 6315** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6316** ^Each term of aOrderBy records a column of the ORDER BY clause. 6317** 6318** The colUsed field indicates which columns of the virtual table may be 6319** required by the current scan. Virtual table columns are numbered from 6320** zero in the order in which they appear within the CREATE TABLE statement 6321** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6322** the corresponding bit is set within the colUsed mask if the column may be 6323** required by SQLite. If the table has at least 64 columns and any column 6324** to the right of the first 63 is required, then bit 63 of colUsed is also 6325** set. In other words, column iCol may be required if the expression 6326** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6327** non-zero. 6328** 6329** The [xBestIndex] method must fill aConstraintUsage[] with information 6330** about what parameters to pass to xFilter. ^If argvIndex>0 then 6331** the right-hand side of the corresponding aConstraint[] is evaluated 6332** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6333** is true, then the constraint is assumed to be fully handled by the 6334** virtual table and is not checked again by SQLite.)^ 6335** 6336** ^The idxNum and idxPtr values are recorded and passed into the 6337** [xFilter] method. 6338** ^[sqlite3_free()] is used to free idxPtr if and only if 6339** needToFreeIdxPtr is true. 6340** 6341** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6342** the correct order to satisfy the ORDER BY clause so that no separate 6343** sorting step is required. 6344** 6345** ^The estimatedCost value is an estimate of the cost of a particular 6346** strategy. A cost of N indicates that the cost of the strategy is similar 6347** to a linear scan of an SQLite table with N rows. A cost of log(N) 6348** indicates that the expense of the operation is similar to that of a 6349** binary search on a unique indexed field of an SQLite table with N rows. 6350** 6351** ^The estimatedRows value is an estimate of the number of rows that 6352** will be returned by the strategy. 6353** 6354** The xBestIndex method may optionally populate the idxFlags field with a 6355** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6356** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6357** assumes that the strategy may visit at most one row. 6358** 6359** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6360** SQLite also assumes that if a call to the xUpdate() method is made as 6361** part of the same statement to delete or update a virtual table row and the 6362** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6363** any database changes. In other words, if the xUpdate() returns 6364** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6365** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6366** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6367** the xUpdate method are automatically rolled back by SQLite. 6368** 6369** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6370** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6371** If a virtual table extension is 6372** used with an SQLite version earlier than 3.8.2, the results of attempting 6373** to read or write the estimatedRows field are undefined (but are likely 6374** to included crashing the application). The estimatedRows field should 6375** therefore only be used if [sqlite3_libversion_number()] returns a 6376** value greater than or equal to 3008002. Similarly, the idxFlags field 6377** was added for [version 3.9.0] ([dateof:3.9.0]). 6378** It may therefore only be used if 6379** sqlite3_libversion_number() returns a value greater than or equal to 6380** 3009000. 6381*/ 6382struct sqlite3_index_info { 6383 /* Inputs */ 6384 int nConstraint; /* Number of entries in aConstraint */ 6385 struct sqlite3_index_constraint { 6386 int iColumn; /* Column constrained. -1 for ROWID */ 6387 unsigned char op; /* Constraint operator */ 6388 unsigned char usable; /* True if this constraint is usable */ 6389 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6390 } *aConstraint; /* Table of WHERE clause constraints */ 6391 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6392 struct sqlite3_index_orderby { 6393 int iColumn; /* Column number */ 6394 unsigned char desc; /* True for DESC. False for ASC. */ 6395 } *aOrderBy; /* The ORDER BY clause */ 6396 /* Outputs */ 6397 struct sqlite3_index_constraint_usage { 6398 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6399 unsigned char omit; /* Do not code a test for this constraint */ 6400 } *aConstraintUsage; 6401 int idxNum; /* Number used to identify the index */ 6402 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6403 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6404 int orderByConsumed; /* True if output is already ordered */ 6405 double estimatedCost; /* Estimated cost of using this index */ 6406 /* Fields below are only available in SQLite 3.8.2 and later */ 6407 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6408 /* Fields below are only available in SQLite 3.9.0 and later */ 6409 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6410 /* Fields below are only available in SQLite 3.10.0 and later */ 6411 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6412}; 6413 6414/* 6415** CAPI3REF: Virtual Table Scan Flags 6416** 6417** Virtual table implementations are allowed to set the 6418** [sqlite3_index_info].idxFlags field to some combination of 6419** these bits. 6420*/ 6421#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6422 6423/* 6424** CAPI3REF: Virtual Table Constraint Operator Codes 6425** 6426** These macros defined the allowed values for the 6427** [sqlite3_index_info].aConstraint[].op field. Each value represents 6428** an operator that is part of a constraint term in the wHERE clause of 6429** a query that uses a [virtual table]. 6430*/ 6431#define SQLITE_INDEX_CONSTRAINT_EQ 2 6432#define SQLITE_INDEX_CONSTRAINT_GT 4 6433#define SQLITE_INDEX_CONSTRAINT_LE 8 6434#define SQLITE_INDEX_CONSTRAINT_LT 16 6435#define SQLITE_INDEX_CONSTRAINT_GE 32 6436#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6437#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6438#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6439#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6440#define SQLITE_INDEX_CONSTRAINT_NE 68 6441#define SQLITE_INDEX_CONSTRAINT_ISNOT 69 6442#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70 6443#define SQLITE_INDEX_CONSTRAINT_ISNULL 71 6444#define SQLITE_INDEX_CONSTRAINT_IS 72 6445#define SQLITE_INDEX_CONSTRAINT_FUNCTION 150 6446 6447/* 6448** CAPI3REF: Register A Virtual Table Implementation 6449** METHOD: sqlite3 6450** 6451** ^These routines are used to register a new [virtual table module] name. 6452** ^Module names must be registered before 6453** creating a new [virtual table] using the module and before using a 6454** preexisting [virtual table] for the module. 6455** 6456** ^The module name is registered on the [database connection] specified 6457** by the first parameter. ^The name of the module is given by the 6458** second parameter. ^The third parameter is a pointer to 6459** the implementation of the [virtual table module]. ^The fourth 6460** parameter is an arbitrary client data pointer that is passed through 6461** into the [xCreate] and [xConnect] methods of the virtual table module 6462** when a new virtual table is be being created or reinitialized. 6463** 6464** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6465** is a pointer to a destructor for the pClientData. ^SQLite will 6466** invoke the destructor function (if it is not NULL) when SQLite 6467** no longer needs the pClientData pointer. ^The destructor will also 6468** be invoked if the call to sqlite3_create_module_v2() fails. 6469** ^The sqlite3_create_module() 6470** interface is equivalent to sqlite3_create_module_v2() with a NULL 6471** destructor. 6472*/ 6473int sqlite3_create_module( 6474 sqlite3 *db, /* SQLite connection to register module with */ 6475 const char *zName, /* Name of the module */ 6476 const sqlite3_module *p, /* Methods for the module */ 6477 void *pClientData /* Client data for xCreate/xConnect */ 6478); 6479int sqlite3_create_module_v2( 6480 sqlite3 *db, /* SQLite connection to register module with */ 6481 const char *zName, /* Name of the module */ 6482 const sqlite3_module *p, /* Methods for the module */ 6483 void *pClientData, /* Client data for xCreate/xConnect */ 6484 void(*xDestroy)(void*) /* Module destructor function */ 6485); 6486 6487/* 6488** CAPI3REF: Virtual Table Instance Object 6489** KEYWORDS: sqlite3_vtab 6490** 6491** Every [virtual table module] implementation uses a subclass 6492** of this object to describe a particular instance 6493** of the [virtual table]. Each subclass will 6494** be tailored to the specific needs of the module implementation. 6495** The purpose of this superclass is to define certain fields that are 6496** common to all module implementations. 6497** 6498** ^Virtual tables methods can set an error message by assigning a 6499** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 6500** take care that any prior string is freed by a call to [sqlite3_free()] 6501** prior to assigning a new string to zErrMsg. ^After the error message 6502** is delivered up to the client application, the string will be automatically 6503** freed by sqlite3_free() and the zErrMsg field will be zeroed. 6504*/ 6505struct sqlite3_vtab { 6506 const sqlite3_module *pModule; /* The module for this virtual table */ 6507 int nRef; /* Number of open cursors */ 6508 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 6509 /* Virtual table implementations will typically add additional fields */ 6510}; 6511 6512/* 6513** CAPI3REF: Virtual Table Cursor Object 6514** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 6515** 6516** Every [virtual table module] implementation uses a subclass of the 6517** following structure to describe cursors that point into the 6518** [virtual table] and are used 6519** to loop through the virtual table. Cursors are created using the 6520** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 6521** by the [sqlite3_module.xClose | xClose] method. Cursors are used 6522** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 6523** of the module. Each module implementation will define 6524** the content of a cursor structure to suit its own needs. 6525** 6526** This superclass exists in order to define fields of the cursor that 6527** are common to all implementations. 6528*/ 6529struct sqlite3_vtab_cursor { 6530 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 6531 /* Virtual table implementations will typically add additional fields */ 6532}; 6533 6534/* 6535** CAPI3REF: Declare The Schema Of A Virtual Table 6536** 6537** ^The [xCreate] and [xConnect] methods of a 6538** [virtual table module] call this interface 6539** to declare the format (the names and datatypes of the columns) of 6540** the virtual tables they implement. 6541*/ 6542int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 6543 6544/* 6545** CAPI3REF: Overload A Function For A Virtual Table 6546** METHOD: sqlite3 6547** 6548** ^(Virtual tables can provide alternative implementations of functions 6549** using the [xFindFunction] method of the [virtual table module]. 6550** But global versions of those functions 6551** must exist in order to be overloaded.)^ 6552** 6553** ^(This API makes sure a global version of a function with a particular 6554** name and number of parameters exists. If no such function exists 6555** before this API is called, a new function is created.)^ ^The implementation 6556** of the new function always causes an exception to be thrown. So 6557** the new function is not good for anything by itself. Its only 6558** purpose is to be a placeholder function that can be overloaded 6559** by a [virtual table]. 6560*/ 6561int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 6562 6563/* 6564** The interface to the virtual-table mechanism defined above (back up 6565** to a comment remarkably similar to this one) is currently considered 6566** to be experimental. The interface might change in incompatible ways. 6567** If this is a problem for you, do not use the interface at this time. 6568** 6569** When the virtual-table mechanism stabilizes, we will declare the 6570** interface fixed, support it indefinitely, and remove this comment. 6571*/ 6572 6573/* 6574** CAPI3REF: A Handle To An Open BLOB 6575** KEYWORDS: {BLOB handle} {BLOB handles} 6576** 6577** An instance of this object represents an open BLOB on which 6578** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 6579** ^Objects of this type are created by [sqlite3_blob_open()] 6580** and destroyed by [sqlite3_blob_close()]. 6581** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 6582** can be used to read or write small subsections of the BLOB. 6583** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 6584*/ 6585typedef struct sqlite3_blob sqlite3_blob; 6586 6587/* 6588** CAPI3REF: Open A BLOB For Incremental I/O 6589** METHOD: sqlite3 6590** CONSTRUCTOR: sqlite3_blob 6591** 6592** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 6593** in row iRow, column zColumn, table zTable in database zDb; 6594** in other words, the same BLOB that would be selected by: 6595** 6596** <pre> 6597** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 6598** </pre>)^ 6599** 6600** ^(Parameter zDb is not the filename that contains the database, but 6601** rather the symbolic name of the database. For attached databases, this is 6602** the name that appears after the AS keyword in the [ATTACH] statement. 6603** For the main database file, the database name is "main". For TEMP 6604** tables, the database name is "temp".)^ 6605** 6606** ^If the flags parameter is non-zero, then the BLOB is opened for read 6607** and write access. ^If the flags parameter is zero, the BLOB is opened for 6608** read-only access. 6609** 6610** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 6611** in *ppBlob. Otherwise an [error code] is returned and, unless the error 6612** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 6613** the API is not misused, it is always safe to call [sqlite3_blob_close()] 6614** on *ppBlob after this function it returns. 6615** 6616** This function fails with SQLITE_ERROR if any of the following are true: 6617** <ul> 6618** <li> ^(Database zDb does not exist)^, 6619** <li> ^(Table zTable does not exist within database zDb)^, 6620** <li> ^(Table zTable is a WITHOUT ROWID table)^, 6621** <li> ^(Column zColumn does not exist)^, 6622** <li> ^(Row iRow is not present in the table)^, 6623** <li> ^(The specified column of row iRow contains a value that is not 6624** a TEXT or BLOB value)^, 6625** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 6626** constraint and the blob is being opened for read/write access)^, 6627** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 6628** column zColumn is part of a [child key] definition and the blob is 6629** being opened for read/write access)^. 6630** </ul> 6631** 6632** ^Unless it returns SQLITE_MISUSE, this function sets the 6633** [database connection] error code and message accessible via 6634** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6635** 6636** A BLOB referenced by sqlite3_blob_open() may be read using the 6637** [sqlite3_blob_read()] interface and modified by using 6638** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 6639** different row of the same table using the [sqlite3_blob_reopen()] 6640** interface. However, the column, table, or database of a [BLOB handle] 6641** cannot be changed after the [BLOB handle] is opened. 6642** 6643** ^(If the row that a BLOB handle points to is modified by an 6644** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 6645** then the BLOB handle is marked as "expired". 6646** This is true if any column of the row is changed, even a column 6647** other than the one the BLOB handle is open on.)^ 6648** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 6649** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 6650** ^(Changes written into a BLOB prior to the BLOB expiring are not 6651** rolled back by the expiration of the BLOB. Such changes will eventually 6652** commit if the transaction continues to completion.)^ 6653** 6654** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 6655** the opened blob. ^The size of a blob may not be changed by this 6656** interface. Use the [UPDATE] SQL command to change the size of a 6657** blob. 6658** 6659** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 6660** and the built-in [zeroblob] SQL function may be used to create a 6661** zero-filled blob to read or write using the incremental-blob interface. 6662** 6663** To avoid a resource leak, every open [BLOB handle] should eventually 6664** be released by a call to [sqlite3_blob_close()]. 6665** 6666** See also: [sqlite3_blob_close()], 6667** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 6668** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 6669*/ 6670int sqlite3_blob_open( 6671 sqlite3*, 6672 const char *zDb, 6673 const char *zTable, 6674 const char *zColumn, 6675 sqlite3_int64 iRow, 6676 int flags, 6677 sqlite3_blob **ppBlob 6678); 6679 6680/* 6681** CAPI3REF: Move a BLOB Handle to a New Row 6682** METHOD: sqlite3_blob 6683** 6684** ^This function is used to move an existing [BLOB handle] so that it points 6685** to a different row of the same database table. ^The new row is identified 6686** by the rowid value passed as the second argument. Only the row can be 6687** changed. ^The database, table and column on which the blob handle is open 6688** remain the same. Moving an existing [BLOB handle] to a new row is 6689** faster than closing the existing handle and opening a new one. 6690** 6691** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 6692** it must exist and there must be either a blob or text value stored in 6693** the nominated column.)^ ^If the new row is not present in the table, or if 6694** it does not contain a blob or text value, or if another error occurs, an 6695** SQLite error code is returned and the blob handle is considered aborted. 6696** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 6697** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 6698** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 6699** always returns zero. 6700** 6701** ^This function sets the database handle error code and message. 6702*/ 6703int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 6704 6705/* 6706** CAPI3REF: Close A BLOB Handle 6707** DESTRUCTOR: sqlite3_blob 6708** 6709** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 6710** unconditionally. Even if this routine returns an error code, the 6711** handle is still closed.)^ 6712** 6713** ^If the blob handle being closed was opened for read-write access, and if 6714** the database is in auto-commit mode and there are no other open read-write 6715** blob handles or active write statements, the current transaction is 6716** committed. ^If an error occurs while committing the transaction, an error 6717** code is returned and the transaction rolled back. 6718** 6719** Calling this function with an argument that is not a NULL pointer or an 6720** open blob handle results in undefined behaviour. ^Calling this routine 6721** with a null pointer (such as would be returned by a failed call to 6722** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 6723** is passed a valid open blob handle, the values returned by the 6724** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 6725*/ 6726int sqlite3_blob_close(sqlite3_blob *); 6727 6728/* 6729** CAPI3REF: Return The Size Of An Open BLOB 6730** METHOD: sqlite3_blob 6731** 6732** ^Returns the size in bytes of the BLOB accessible via the 6733** successfully opened [BLOB handle] in its only argument. ^The 6734** incremental blob I/O routines can only read or overwriting existing 6735** blob content; they cannot change the size of a blob. 6736** 6737** This routine only works on a [BLOB handle] which has been created 6738** by a prior successful call to [sqlite3_blob_open()] and which has not 6739** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6740** to this routine results in undefined and probably undesirable behavior. 6741*/ 6742int sqlite3_blob_bytes(sqlite3_blob *); 6743 6744/* 6745** CAPI3REF: Read Data From A BLOB Incrementally 6746** METHOD: sqlite3_blob 6747** 6748** ^(This function is used to read data from an open [BLOB handle] into a 6749** caller-supplied buffer. N bytes of data are copied into buffer Z 6750** from the open BLOB, starting at offset iOffset.)^ 6751** 6752** ^If offset iOffset is less than N bytes from the end of the BLOB, 6753** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6754** less than zero, [SQLITE_ERROR] is returned and no data is read. 6755** ^The size of the blob (and hence the maximum value of N+iOffset) 6756** can be determined using the [sqlite3_blob_bytes()] interface. 6757** 6758** ^An attempt to read from an expired [BLOB handle] fails with an 6759** error code of [SQLITE_ABORT]. 6760** 6761** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6762** Otherwise, an [error code] or an [extended error code] is returned.)^ 6763** 6764** This routine only works on a [BLOB handle] which has been created 6765** by a prior successful call to [sqlite3_blob_open()] and which has not 6766** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6767** to this routine results in undefined and probably undesirable behavior. 6768** 6769** See also: [sqlite3_blob_write()]. 6770*/ 6771int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6772 6773/* 6774** CAPI3REF: Write Data Into A BLOB Incrementally 6775** METHOD: sqlite3_blob 6776** 6777** ^(This function is used to write data into an open [BLOB handle] from a 6778** caller-supplied buffer. N bytes of data are copied from the buffer Z 6779** into the open BLOB, starting at offset iOffset.)^ 6780** 6781** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6782** Otherwise, an [error code] or an [extended error code] is returned.)^ 6783** ^Unless SQLITE_MISUSE is returned, this function sets the 6784** [database connection] error code and message accessible via 6785** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6786** 6787** ^If the [BLOB handle] passed as the first argument was not opened for 6788** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6789** this function returns [SQLITE_READONLY]. 6790** 6791** This function may only modify the contents of the BLOB; it is 6792** not possible to increase the size of a BLOB using this API. 6793** ^If offset iOffset is less than N bytes from the end of the BLOB, 6794** [SQLITE_ERROR] is returned and no data is written. The size of the 6795** BLOB (and hence the maximum value of N+iOffset) can be determined 6796** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6797** than zero [SQLITE_ERROR] is returned and no data is written. 6798** 6799** ^An attempt to write to an expired [BLOB handle] fails with an 6800** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6801** before the [BLOB handle] expired are not rolled back by the 6802** expiration of the handle, though of course those changes might 6803** have been overwritten by the statement that expired the BLOB handle 6804** or by other independent statements. 6805** 6806** This routine only works on a [BLOB handle] which has been created 6807** by a prior successful call to [sqlite3_blob_open()] and which has not 6808** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6809** to this routine results in undefined and probably undesirable behavior. 6810** 6811** See also: [sqlite3_blob_read()]. 6812*/ 6813int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6814 6815/* 6816** CAPI3REF: Virtual File System Objects 6817** 6818** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6819** that SQLite uses to interact 6820** with the underlying operating system. Most SQLite builds come with a 6821** single default VFS that is appropriate for the host computer. 6822** New VFSes can be registered and existing VFSes can be unregistered. 6823** The following interfaces are provided. 6824** 6825** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6826** ^Names are case sensitive. 6827** ^Names are zero-terminated UTF-8 strings. 6828** ^If there is no match, a NULL pointer is returned. 6829** ^If zVfsName is NULL then the default VFS is returned. 6830** 6831** ^New VFSes are registered with sqlite3_vfs_register(). 6832** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6833** ^The same VFS can be registered multiple times without injury. 6834** ^To make an existing VFS into the default VFS, register it again 6835** with the makeDflt flag set. If two different VFSes with the 6836** same name are registered, the behavior is undefined. If a 6837** VFS is registered with a name that is NULL or an empty string, 6838** then the behavior is undefined. 6839** 6840** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6841** ^(If the default VFS is unregistered, another VFS is chosen as 6842** the default. The choice for the new VFS is arbitrary.)^ 6843*/ 6844sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6845int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6846int sqlite3_vfs_unregister(sqlite3_vfs*); 6847 6848/* 6849** CAPI3REF: Mutexes 6850** 6851** The SQLite core uses these routines for thread 6852** synchronization. Though they are intended for internal 6853** use by SQLite, code that links against SQLite is 6854** permitted to use any of these routines. 6855** 6856** The SQLite source code contains multiple implementations 6857** of these mutex routines. An appropriate implementation 6858** is selected automatically at compile-time. The following 6859** implementations are available in the SQLite core: 6860** 6861** <ul> 6862** <li> SQLITE_MUTEX_PTHREADS 6863** <li> SQLITE_MUTEX_W32 6864** <li> SQLITE_MUTEX_NOOP 6865** </ul> 6866** 6867** The SQLITE_MUTEX_NOOP implementation is a set of routines 6868** that does no real locking and is appropriate for use in 6869** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6870** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6871** and Windows. 6872** 6873** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6874** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6875** implementation is included with the library. In this case the 6876** application must supply a custom mutex implementation using the 6877** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6878** before calling sqlite3_initialize() or any other public sqlite3_ 6879** function that calls sqlite3_initialize(). 6880** 6881** ^The sqlite3_mutex_alloc() routine allocates a new 6882** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6883** routine returns NULL if it is unable to allocate the requested 6884** mutex. The argument to sqlite3_mutex_alloc() must one of these 6885** integer constants: 6886** 6887** <ul> 6888** <li> SQLITE_MUTEX_FAST 6889** <li> SQLITE_MUTEX_RECURSIVE 6890** <li> SQLITE_MUTEX_STATIC_MASTER 6891** <li> SQLITE_MUTEX_STATIC_MEM 6892** <li> SQLITE_MUTEX_STATIC_OPEN 6893** <li> SQLITE_MUTEX_STATIC_PRNG 6894** <li> SQLITE_MUTEX_STATIC_LRU 6895** <li> SQLITE_MUTEX_STATIC_PMEM 6896** <li> SQLITE_MUTEX_STATIC_APP1 6897** <li> SQLITE_MUTEX_STATIC_APP2 6898** <li> SQLITE_MUTEX_STATIC_APP3 6899** <li> SQLITE_MUTEX_STATIC_VFS1 6900** <li> SQLITE_MUTEX_STATIC_VFS2 6901** <li> SQLITE_MUTEX_STATIC_VFS3 6902** </ul> 6903** 6904** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6905** cause sqlite3_mutex_alloc() to create 6906** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6907** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6908** The mutex implementation does not need to make a distinction 6909** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6910** not want to. SQLite will only request a recursive mutex in 6911** cases where it really needs one. If a faster non-recursive mutex 6912** implementation is available on the host platform, the mutex subsystem 6913** might return such a mutex in response to SQLITE_MUTEX_FAST. 6914** 6915** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6916** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6917** a pointer to a static preexisting mutex. ^Nine static mutexes are 6918** used by the current version of SQLite. Future versions of SQLite 6919** may add additional static mutexes. Static mutexes are for internal 6920** use by SQLite only. Applications that use SQLite mutexes should 6921** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6922** SQLITE_MUTEX_RECURSIVE. 6923** 6924** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6925** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6926** returns a different mutex on every call. ^For the static 6927** mutex types, the same mutex is returned on every call that has 6928** the same type number. 6929** 6930** ^The sqlite3_mutex_free() routine deallocates a previously 6931** allocated dynamic mutex. Attempting to deallocate a static 6932** mutex results in undefined behavior. 6933** 6934** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6935** to enter a mutex. ^If another thread is already within the mutex, 6936** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6937** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6938** upon successful entry. ^(Mutexes created using 6939** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6940** In such cases, the 6941** mutex must be exited an equal number of times before another thread 6942** can enter.)^ If the same thread tries to enter any mutex other 6943** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6944** 6945** ^(Some systems (for example, Windows 95) do not support the operation 6946** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6947** will always return SQLITE_BUSY. The SQLite core only ever uses 6948** sqlite3_mutex_try() as an optimization so this is acceptable 6949** behavior.)^ 6950** 6951** ^The sqlite3_mutex_leave() routine exits a mutex that was 6952** previously entered by the same thread. The behavior 6953** is undefined if the mutex is not currently entered by the 6954** calling thread or is not currently allocated. 6955** 6956** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6957** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6958** behave as no-ops. 6959** 6960** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6961*/ 6962sqlite3_mutex *sqlite3_mutex_alloc(int); 6963void sqlite3_mutex_free(sqlite3_mutex*); 6964void sqlite3_mutex_enter(sqlite3_mutex*); 6965int sqlite3_mutex_try(sqlite3_mutex*); 6966void sqlite3_mutex_leave(sqlite3_mutex*); 6967 6968/* 6969** CAPI3REF: Mutex Methods Object 6970** 6971** An instance of this structure defines the low-level routines 6972** used to allocate and use mutexes. 6973** 6974** Usually, the default mutex implementations provided by SQLite are 6975** sufficient, however the application has the option of substituting a custom 6976** implementation for specialized deployments or systems for which SQLite 6977** does not provide a suitable implementation. In this case, the application 6978** creates and populates an instance of this structure to pass 6979** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6980** Additionally, an instance of this structure can be used as an 6981** output variable when querying the system for the current mutex 6982** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6983** 6984** ^The xMutexInit method defined by this structure is invoked as 6985** part of system initialization by the sqlite3_initialize() function. 6986** ^The xMutexInit routine is called by SQLite exactly once for each 6987** effective call to [sqlite3_initialize()]. 6988** 6989** ^The xMutexEnd method defined by this structure is invoked as 6990** part of system shutdown by the sqlite3_shutdown() function. The 6991** implementation of this method is expected to release all outstanding 6992** resources obtained by the mutex methods implementation, especially 6993** those obtained by the xMutexInit method. ^The xMutexEnd() 6994** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6995** 6996** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6997** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6998** xMutexNotheld) implement the following interfaces (respectively): 6999** 7000** <ul> 7001** <li> [sqlite3_mutex_alloc()] </li> 7002** <li> [sqlite3_mutex_free()] </li> 7003** <li> [sqlite3_mutex_enter()] </li> 7004** <li> [sqlite3_mutex_try()] </li> 7005** <li> [sqlite3_mutex_leave()] </li> 7006** <li> [sqlite3_mutex_held()] </li> 7007** <li> [sqlite3_mutex_notheld()] </li> 7008** </ul>)^ 7009** 7010** The only difference is that the public sqlite3_XXX functions enumerated 7011** above silently ignore any invocations that pass a NULL pointer instead 7012** of a valid mutex handle. The implementations of the methods defined 7013** by this structure are not required to handle this case, the results 7014** of passing a NULL pointer instead of a valid mutex handle are undefined 7015** (i.e. it is acceptable to provide an implementation that segfaults if 7016** it is passed a NULL pointer). 7017** 7018** The xMutexInit() method must be threadsafe. It must be harmless to 7019** invoke xMutexInit() multiple times within the same process and without 7020** intervening calls to xMutexEnd(). Second and subsequent calls to 7021** xMutexInit() must be no-ops. 7022** 7023** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 7024** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 7025** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 7026** memory allocation for a fast or recursive mutex. 7027** 7028** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 7029** called, but only if the prior call to xMutexInit returned SQLITE_OK. 7030** If xMutexInit fails in any way, it is expected to clean up after itself 7031** prior to returning. 7032*/ 7033typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 7034struct sqlite3_mutex_methods { 7035 int (*xMutexInit)(void); 7036 int (*xMutexEnd)(void); 7037 sqlite3_mutex *(*xMutexAlloc)(int); 7038 void (*xMutexFree)(sqlite3_mutex *); 7039 void (*xMutexEnter)(sqlite3_mutex *); 7040 int (*xMutexTry)(sqlite3_mutex *); 7041 void (*xMutexLeave)(sqlite3_mutex *); 7042 int (*xMutexHeld)(sqlite3_mutex *); 7043 int (*xMutexNotheld)(sqlite3_mutex *); 7044}; 7045 7046/* 7047** CAPI3REF: Mutex Verification Routines 7048** 7049** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 7050** are intended for use inside assert() statements. The SQLite core 7051** never uses these routines except inside an assert() and applications 7052** are advised to follow the lead of the core. The SQLite core only 7053** provides implementations for these routines when it is compiled 7054** with the SQLITE_DEBUG flag. External mutex implementations 7055** are only required to provide these routines if SQLITE_DEBUG is 7056** defined and if NDEBUG is not defined. 7057** 7058** These routines should return true if the mutex in their argument 7059** is held or not held, respectively, by the calling thread. 7060** 7061** The implementation is not required to provide versions of these 7062** routines that actually work. If the implementation does not provide working 7063** versions of these routines, it should at least provide stubs that always 7064** return true so that one does not get spurious assertion failures. 7065** 7066** If the argument to sqlite3_mutex_held() is a NULL pointer then 7067** the routine should return 1. This seems counter-intuitive since 7068** clearly the mutex cannot be held if it does not exist. But 7069** the reason the mutex does not exist is because the build is not 7070** using mutexes. And we do not want the assert() containing the 7071** call to sqlite3_mutex_held() to fail, so a non-zero return is 7072** the appropriate thing to do. The sqlite3_mutex_notheld() 7073** interface should also return 1 when given a NULL pointer. 7074*/ 7075#ifndef NDEBUG 7076int sqlite3_mutex_held(sqlite3_mutex*); 7077int sqlite3_mutex_notheld(sqlite3_mutex*); 7078#endif 7079 7080/* 7081** CAPI3REF: Mutex Types 7082** 7083** The [sqlite3_mutex_alloc()] interface takes a single argument 7084** which is one of these integer constants. 7085** 7086** The set of static mutexes may change from one SQLite release to the 7087** next. Applications that override the built-in mutex logic must be 7088** prepared to accommodate additional static mutexes. 7089*/ 7090#define SQLITE_MUTEX_FAST 0 7091#define SQLITE_MUTEX_RECURSIVE 1 7092#define SQLITE_MUTEX_STATIC_MASTER 2 7093#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 7094#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 7095#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 7096#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 7097#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 7098#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 7099#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 7100#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 7101#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 7102#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 7103#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 7104#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 7105#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 7106 7107/* 7108** CAPI3REF: Retrieve the mutex for a database connection 7109** METHOD: sqlite3 7110** 7111** ^This interface returns a pointer the [sqlite3_mutex] object that 7112** serializes access to the [database connection] given in the argument 7113** when the [threading mode] is Serialized. 7114** ^If the [threading mode] is Single-thread or Multi-thread then this 7115** routine returns a NULL pointer. 7116*/ 7117sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 7118 7119/* 7120** CAPI3REF: Low-Level Control Of Database Files 7121** METHOD: sqlite3 7122** KEYWORDS: {file control} 7123** 7124** ^The [sqlite3_file_control()] interface makes a direct call to the 7125** xFileControl method for the [sqlite3_io_methods] object associated 7126** with a particular database identified by the second argument. ^The 7127** name of the database is "main" for the main database or "temp" for the 7128** TEMP database, or the name that appears after the AS keyword for 7129** databases that are added using the [ATTACH] SQL command. 7130** ^A NULL pointer can be used in place of "main" to refer to the 7131** main database file. 7132** ^The third and fourth parameters to this routine 7133** are passed directly through to the second and third parameters of 7134** the xFileControl method. ^The return value of the xFileControl 7135** method becomes the return value of this routine. 7136** 7137** A few opcodes for [sqlite3_file_control()] are handled directly 7138** by the SQLite core and never invoke the 7139** sqlite3_io_methods.xFileControl method. 7140** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes 7141** a pointer to the underlying [sqlite3_file] object to be written into 7142** the space pointed to by the 4th parameter. The 7143** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns 7144** the [sqlite3_file] object associated with the journal file instead of 7145** the main database. The [SQLITE_FCNTL_VFS_POINTER] opcode returns 7146** a pointer to the underlying [sqlite3_vfs] object for the file. 7147** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter 7148** from the pager. 7149** 7150** ^If the second parameter (zDbName) does not match the name of any 7151** open database file, then SQLITE_ERROR is returned. ^This error 7152** code is not remembered and will not be recalled by [sqlite3_errcode()] 7153** or [sqlite3_errmsg()]. The underlying xFileControl method might 7154** also return SQLITE_ERROR. There is no way to distinguish between 7155** an incorrect zDbName and an SQLITE_ERROR return from the underlying 7156** xFileControl method. 7157** 7158** See also: [file control opcodes] 7159*/ 7160int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 7161 7162/* 7163** CAPI3REF: Testing Interface 7164** 7165** ^The sqlite3_test_control() interface is used to read out internal 7166** state of SQLite and to inject faults into SQLite for testing 7167** purposes. ^The first parameter is an operation code that determines 7168** the number, meaning, and operation of all subsequent parameters. 7169** 7170** This interface is not for use by applications. It exists solely 7171** for verifying the correct operation of the SQLite library. Depending 7172** on how the SQLite library is compiled, this interface might not exist. 7173** 7174** The details of the operation codes, their meanings, the parameters 7175** they take, and what they do are all subject to change without notice. 7176** Unlike most of the SQLite API, this function is not guaranteed to 7177** operate consistently from one release to the next. 7178*/ 7179int sqlite3_test_control(int op, ...); 7180 7181/* 7182** CAPI3REF: Testing Interface Operation Codes 7183** 7184** These constants are the valid operation code parameters used 7185** as the first argument to [sqlite3_test_control()]. 7186** 7187** These parameters and their meanings are subject to change 7188** without notice. These values are for testing purposes only. 7189** Applications should not use any of these parameters or the 7190** [sqlite3_test_control()] interface. 7191*/ 7192#define SQLITE_TESTCTRL_FIRST 5 7193#define SQLITE_TESTCTRL_PRNG_SAVE 5 7194#define SQLITE_TESTCTRL_PRNG_RESTORE 6 7195#define SQLITE_TESTCTRL_PRNG_RESET 7 7196#define SQLITE_TESTCTRL_BITVEC_TEST 8 7197#define SQLITE_TESTCTRL_FAULT_INSTALL 9 7198#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 7199#define SQLITE_TESTCTRL_PENDING_BYTE 11 7200#define SQLITE_TESTCTRL_ASSERT 12 7201#define SQLITE_TESTCTRL_ALWAYS 13 7202#define SQLITE_TESTCTRL_RESERVE 14 7203#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7204#define SQLITE_TESTCTRL_ISKEYWORD 16 /* NOT USED */ 7205#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */ 7206#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7207#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7208#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7209#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7210#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7211#define SQLITE_TESTCTRL_BYTEORDER 22 7212#define SQLITE_TESTCTRL_ISINIT 23 7213#define SQLITE_TESTCTRL_SORTER_MMAP 24 7214#define SQLITE_TESTCTRL_IMPOSTER 25 7215#define SQLITE_TESTCTRL_PARSER_COVERAGE 26 7216#define SQLITE_TESTCTRL_LAST 26 /* Largest TESTCTRL */ 7217 7218/* 7219** CAPI3REF: SQL Keyword Checking 7220** 7221** These routines provide access to the set of SQL language keywords 7222** recognized by SQLite. Applications can uses these routines to determine 7223** whether or not a specific identifier needs to be escaped (for example, 7224** by enclosing in double-quotes) so as not to confuse the parser. 7225** 7226** The sqlite3_keyword_count() interface returns the number of distinct 7227** keywords understood by SQLite. 7228** 7229** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and 7230** makes *Z point to that keyword expressed as UTF8 and writes the number 7231** of bytes in the keyword into *L. The string that *Z points to is not 7232** zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns 7233** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z 7234** or L are NULL or invalid pointers then calls to 7235** sqlite3_keyword_name(N,Z,L) result in undefined behavior. 7236** 7237** The sqlite3_keyword_check(Z,L) interface checks to see whether or not 7238** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero 7239** if it is and zero if not. 7240** 7241** The parser used by SQLite is forgiving. It is often possible to use 7242** a keyword as an identifier as long as such use does not result in a 7243** parsing ambiguity. For example, the statement 7244** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and 7245** creates a new table named "BEGIN" with three columns named 7246** "REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid 7247** using keywords as identifiers. Common techniques used to avoid keyword 7248** name collisions include: 7249** <ul> 7250** <li> Put all identifier names inside double-quotes. This is the official 7251** SQL way to escape identifier names. 7252** <li> Put identifier names inside [...]. This is not standard SQL, 7253** but it is what SQL Server does and so lots of programmers use this 7254** technique. 7255** <li> Begin every identifier with the letter "Z" as no SQL keywords start 7256** with "Z". 7257** <li> Include a digit somewhere in every identifier name. 7258** </ul> 7259** 7260** Note that the number of keywords understood by SQLite can depend on 7261** compile-time options. For example, "VACUUM" is not a keyword if 7262** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option. Also, 7263** new keywords may be added to future releases of SQLite. 7264*/ 7265int sqlite3_keyword_count(void); 7266int sqlite3_keyword_name(int,const char**,int*); 7267int sqlite3_keyword_check(const char*,int); 7268 7269/* 7270** CAPI3REF: Dynamic String Object 7271** KEYWORDS: {dynamic string} 7272** 7273** An instance of the sqlite3_str object contains a dynamically-sized 7274** string under construction. 7275** 7276** The lifecycle of an sqlite3_str object is as follows: 7277** <ol> 7278** <li> ^The sqlite3_str object is created using [sqlite3_str_new()]. 7279** <li> ^Text is appended to the sqlite3_str object using various 7280** methods, such as [sqlite3_str_appendf()]. 7281** <li> ^The sqlite3_str object is destroyed and the string it created 7282** is returned using the [sqlite3_str_finish()] interface. 7283** </ol> 7284*/ 7285typedef struct sqlite3_str sqlite3_str; 7286 7287/* 7288** CAPI3REF: Create A New Dynamic String Object 7289** CONSTRUCTOR: sqlite3_str 7290** 7291** ^The [sqlite3_str_new(D)] interface allocates and initializes 7292** a new [sqlite3_str] object. To avoid memory leaks, the object returned by 7293** [sqlite3_str_new()] must be freed by a subsequent call to 7294** [sqlite3_str_finish(X)]. 7295** 7296** ^The [sqlite3_str_new(D)] interface always returns a pointer to a 7297** valid [sqlite3_str] object, though in the event of an out-of-memory 7298** error the returned object might be a special singleton that will 7299** silently reject new text, always return SQLITE_NOMEM from 7300** [sqlite3_str_errcode()], always return 0 for 7301** [sqlite3_str_length()], and always return NULL from 7302** [sqlite3_str_finish(X)]. It is always safe to use the value 7303** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter 7304** to any of the other [sqlite3_str] methods. 7305** 7306** The D parameter to [sqlite3_str_new(D)] may be NULL. If the 7307** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum 7308** length of the string contained in the [sqlite3_str] object will be 7309** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead 7310** of [SQLITE_MAX_LENGTH]. 7311*/ 7312sqlite3_str *sqlite3_str_new(sqlite3*); 7313 7314/* 7315** CAPI3REF: Finalize A Dynamic String 7316** DESTRUCTOR: sqlite3_str 7317** 7318** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X 7319** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()] 7320** that contains the constructed string. The calling application should 7321** pass the returned value to [sqlite3_free()] to avoid a memory leak. 7322** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any 7323** errors were encountered during construction of the string. ^The 7324** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the 7325** string in [sqlite3_str] object X is zero bytes long. 7326*/ 7327char *sqlite3_str_finish(sqlite3_str*); 7328 7329/* 7330** CAPI3REF: Add Content To A Dynamic String 7331** METHOD: sqlite3_str 7332** 7333** These interfaces add content to an sqlite3_str object previously obtained 7334** from [sqlite3_str_new()]. 7335** 7336** ^The [sqlite3_str_appendf(X,F,...)] and 7337** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf] 7338** functionality of SQLite to append formatted text onto the end of 7339** [sqlite3_str] object X. 7340** 7341** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S 7342** onto the end of the [sqlite3_str] object X. N must be non-negative. 7343** S must contain at least N non-zero bytes of content. To append a 7344** zero-terminated string in its entirety, use the [sqlite3_str_appendall()] 7345** method instead. 7346** 7347** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of 7348** zero-terminated string S onto the end of [sqlite3_str] object X. 7349** 7350** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the 7351** single-byte character C onto the end of [sqlite3_str] object X. 7352** ^This method can be used, for example, to add whitespace indentation. 7353** 7354** ^The [sqlite3_str_reset(X)] method resets the string under construction 7355** inside [sqlite3_str] object X back to zero bytes in length. 7356** 7357** These methods do not return a result code. ^If an error occurs, that fact 7358** is recorded in the [sqlite3_str] object and can be recovered by a 7359** subsequent call to [sqlite3_str_errcode(X)]. 7360*/ 7361void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...); 7362void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list); 7363void sqlite3_str_append(sqlite3_str*, const char *zIn, int N); 7364void sqlite3_str_appendall(sqlite3_str*, const char *zIn); 7365void sqlite3_str_appendchar(sqlite3_str*, int N, char C); 7366void sqlite3_str_reset(sqlite3_str*); 7367 7368/* 7369** CAPI3REF: Status Of A Dynamic String 7370** METHOD: sqlite3_str 7371** 7372** These interfaces return the current status of an [sqlite3_str] object. 7373** 7374** ^If any prior errors have occurred while constructing the dynamic string 7375** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return 7376** an appropriate error code. ^The [sqlite3_str_errcode(X)] method returns 7377** [SQLITE_NOMEM] following any out-of-memory error, or 7378** [SQLITE_TOOBIG] if the size of the dynamic string exceeds 7379** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors. 7380** 7381** ^The [sqlite3_str_length(X)] method returns the current length, in bytes, 7382** of the dynamic string under construction in [sqlite3_str] object X. 7383** ^The length returned by [sqlite3_str_length(X)] does not include the 7384** zero-termination byte. 7385** 7386** ^The [sqlite3_str_value(X)] method returns a pointer to the current 7387** content of the dynamic string under construction in X. The value 7388** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X 7389** and might be freed or altered by any subsequent method on the same 7390** [sqlite3_str] object. Applications must not used the pointer returned 7391** [sqlite3_str_value(X)] after any subsequent method call on the same 7392** object. ^Applications may change the content of the string returned 7393** by [sqlite3_str_value(X)] as long as they do not write into any bytes 7394** outside the range of 0 to [sqlite3_str_length(X)] and do not read or 7395** write any byte after any subsequent sqlite3_str method call. 7396*/ 7397int sqlite3_str_errcode(sqlite3_str*); 7398int sqlite3_str_length(sqlite3_str*); 7399char *sqlite3_str_value(sqlite3_str*); 7400 7401/* 7402** CAPI3REF: SQLite Runtime Status 7403** 7404** ^These interfaces are used to retrieve runtime status information 7405** about the performance of SQLite, and optionally to reset various 7406** highwater marks. ^The first argument is an integer code for 7407** the specific parameter to measure. ^(Recognized integer codes 7408** are of the form [status parameters | SQLITE_STATUS_...].)^ 7409** ^The current value of the parameter is returned into *pCurrent. 7410** ^The highest recorded value is returned in *pHighwater. ^If the 7411** resetFlag is true, then the highest record value is reset after 7412** *pHighwater is written. ^(Some parameters do not record the highest 7413** value. For those parameters 7414** nothing is written into *pHighwater and the resetFlag is ignored.)^ 7415** ^(Other parameters record only the highwater mark and not the current 7416** value. For these latter parameters nothing is written into *pCurrent.)^ 7417** 7418** ^The sqlite3_status() and sqlite3_status64() routines return 7419** SQLITE_OK on success and a non-zero [error code] on failure. 7420** 7421** If either the current value or the highwater mark is too large to 7422** be represented by a 32-bit integer, then the values returned by 7423** sqlite3_status() are undefined. 7424** 7425** See also: [sqlite3_db_status()] 7426*/ 7427int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 7428int sqlite3_status64( 7429 int op, 7430 sqlite3_int64 *pCurrent, 7431 sqlite3_int64 *pHighwater, 7432 int resetFlag 7433); 7434 7435 7436/* 7437** CAPI3REF: Status Parameters 7438** KEYWORDS: {status parameters} 7439** 7440** These integer constants designate various run-time status parameters 7441** that can be returned by [sqlite3_status()]. 7442** 7443** <dl> 7444** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 7445** <dd>This parameter is the current amount of memory checked out 7446** using [sqlite3_malloc()], either directly or indirectly. The 7447** figure includes calls made to [sqlite3_malloc()] by the application 7448** and internal memory usage by the SQLite library. Auxiliary page-cache 7449** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 7450** this parameter. The amount returned is the sum of the allocation 7451** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 7452** 7453** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 7454** <dd>This parameter records the largest memory allocation request 7455** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 7456** internal equivalents). Only the value returned in the 7457** *pHighwater parameter to [sqlite3_status()] is of interest. 7458** The value written into the *pCurrent parameter is undefined.</dd>)^ 7459** 7460** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 7461** <dd>This parameter records the number of separate memory allocations 7462** currently checked out.</dd>)^ 7463** 7464** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 7465** <dd>This parameter returns the number of pages used out of the 7466** [pagecache memory allocator] that was configured using 7467** [SQLITE_CONFIG_PAGECACHE]. The 7468** value returned is in pages, not in bytes.</dd>)^ 7469** 7470** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 7471** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 7472** <dd>This parameter returns the number of bytes of page cache 7473** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 7474** buffer and where forced to overflow to [sqlite3_malloc()]. The 7475** returned value includes allocations that overflowed because they 7476** where too large (they were larger than the "sz" parameter to 7477** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 7478** no space was left in the page cache.</dd>)^ 7479** 7480** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 7481** <dd>This parameter records the largest memory allocation request 7482** handed to [pagecache memory allocator]. Only the value returned in the 7483** *pHighwater parameter to [sqlite3_status()] is of interest. 7484** The value written into the *pCurrent parameter is undefined.</dd>)^ 7485** 7486** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt> 7487** <dd>No longer used.</dd> 7488** 7489** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 7490** <dd>No longer used.</dd> 7491** 7492** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 7493** <dd>No longer used.</dd> 7494** 7495** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 7496** <dd>The *pHighwater parameter records the deepest parser stack. 7497** The *pCurrent value is undefined. The *pHighwater value is only 7498** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 7499** </dl> 7500** 7501** New status parameters may be added from time to time. 7502*/ 7503#define SQLITE_STATUS_MEMORY_USED 0 7504#define SQLITE_STATUS_PAGECACHE_USED 1 7505#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 7506#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */ 7507#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */ 7508#define SQLITE_STATUS_MALLOC_SIZE 5 7509#define SQLITE_STATUS_PARSER_STACK 6 7510#define SQLITE_STATUS_PAGECACHE_SIZE 7 7511#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */ 7512#define SQLITE_STATUS_MALLOC_COUNT 9 7513 7514/* 7515** CAPI3REF: Database Connection Status 7516** METHOD: sqlite3 7517** 7518** ^This interface is used to retrieve runtime status information 7519** about a single [database connection]. ^The first argument is the 7520** database connection object to be interrogated. ^The second argument 7521** is an integer constant, taken from the set of 7522** [SQLITE_DBSTATUS options], that 7523** determines the parameter to interrogate. The set of 7524** [SQLITE_DBSTATUS options] is likely 7525** to grow in future releases of SQLite. 7526** 7527** ^The current value of the requested parameter is written into *pCur 7528** and the highest instantaneous value is written into *pHiwtr. ^If 7529** the resetFlg is true, then the highest instantaneous value is 7530** reset back down to the current value. 7531** 7532** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 7533** non-zero [error code] on failure. 7534** 7535** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 7536*/ 7537int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 7538 7539/* 7540** CAPI3REF: Status Parameters for database connections 7541** KEYWORDS: {SQLITE_DBSTATUS options} 7542** 7543** These constants are the available integer "verbs" that can be passed as 7544** the second argument to the [sqlite3_db_status()] interface. 7545** 7546** New verbs may be added in future releases of SQLite. Existing verbs 7547** might be discontinued. Applications should check the return code from 7548** [sqlite3_db_status()] to make sure that the call worked. 7549** The [sqlite3_db_status()] interface will return a non-zero error code 7550** if a discontinued or unsupported verb is invoked. 7551** 7552** <dl> 7553** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 7554** <dd>This parameter returns the number of lookaside memory slots currently 7555** checked out.</dd>)^ 7556** 7557** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 7558** <dd>This parameter returns the number malloc attempts that were 7559** satisfied using lookaside memory. Only the high-water value is meaningful; 7560** the current value is always zero.)^ 7561** 7562** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 7563** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 7564** <dd>This parameter returns the number malloc attempts that might have 7565** been satisfied using lookaside memory but failed due to the amount of 7566** memory requested being larger than the lookaside slot size. 7567** Only the high-water value is meaningful; 7568** the current value is always zero.)^ 7569** 7570** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 7571** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 7572** <dd>This parameter returns the number malloc attempts that might have 7573** been satisfied using lookaside memory but failed due to all lookaside 7574** memory already being in use. 7575** Only the high-water value is meaningful; 7576** the current value is always zero.)^ 7577** 7578** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 7579** <dd>This parameter returns the approximate number of bytes of heap 7580** memory used by all pager caches associated with the database connection.)^ 7581** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 7582** 7583** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 7584** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 7585** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 7586** pager cache is shared between two or more connections the bytes of heap 7587** memory used by that pager cache is divided evenly between the attached 7588** connections.)^ In other words, if none of the pager caches associated 7589** with the database connection are shared, this request returns the same 7590** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 7591** shared, the value returned by this call will be smaller than that returned 7592** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 7593** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 7594** 7595** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 7596** <dd>This parameter returns the approximate number of bytes of heap 7597** memory used to store the schema for all databases associated 7598** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 7599** ^The full amount of memory used by the schemas is reported, even if the 7600** schema memory is shared with other database connections due to 7601** [shared cache mode] being enabled. 7602** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 7603** 7604** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 7605** <dd>This parameter returns the approximate number of bytes of heap 7606** and lookaside memory used by all prepared statements associated with 7607** the database connection.)^ 7608** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 7609** </dd> 7610** 7611** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 7612** <dd>This parameter returns the number of pager cache hits that have 7613** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 7614** is always 0. 7615** </dd> 7616** 7617** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 7618** <dd>This parameter returns the number of pager cache misses that have 7619** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 7620** is always 0. 7621** </dd> 7622** 7623** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 7624** <dd>This parameter returns the number of dirty cache entries that have 7625** been written to disk. Specifically, the number of pages written to the 7626** wal file in wal mode databases, or the number of pages written to the 7627** database file in rollback mode databases. Any pages written as part of 7628** transaction rollback or database recovery operations are not included. 7629** If an IO or other error occurs while writing a page to disk, the effect 7630** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 7631** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 7632** </dd> 7633** 7634** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt> 7635** <dd>This parameter returns the number of dirty cache entries that have 7636** been written to disk in the middle of a transaction due to the page 7637** cache overflowing. Transactions are more efficient if they are written 7638** to disk all at once. When pages spill mid-transaction, that introduces 7639** additional overhead. This parameter can be used help identify 7640** inefficiencies that can be resolve by increasing the cache size. 7641** </dd> 7642** 7643** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 7644** <dd>This parameter returns zero for the current value if and only if 7645** all foreign key constraints (deferred or immediate) have been 7646** resolved.)^ ^The highwater mark is always 0. 7647** </dd> 7648** </dl> 7649*/ 7650#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 7651#define SQLITE_DBSTATUS_CACHE_USED 1 7652#define SQLITE_DBSTATUS_SCHEMA_USED 2 7653#define SQLITE_DBSTATUS_STMT_USED 3 7654#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 7655#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 7656#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 7657#define SQLITE_DBSTATUS_CACHE_HIT 7 7658#define SQLITE_DBSTATUS_CACHE_MISS 8 7659#define SQLITE_DBSTATUS_CACHE_WRITE 9 7660#define SQLITE_DBSTATUS_DEFERRED_FKS 10 7661#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 7662#define SQLITE_DBSTATUS_CACHE_SPILL 12 7663#define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */ 7664 7665 7666/* 7667** CAPI3REF: Prepared Statement Status 7668** METHOD: sqlite3_stmt 7669** 7670** ^(Each prepared statement maintains various 7671** [SQLITE_STMTSTATUS counters] that measure the number 7672** of times it has performed specific operations.)^ These counters can 7673** be used to monitor the performance characteristics of the prepared 7674** statements. For example, if the number of table steps greatly exceeds 7675** the number of table searches or result rows, that would tend to indicate 7676** that the prepared statement is using a full table scan rather than 7677** an index. 7678** 7679** ^(This interface is used to retrieve and reset counter values from 7680** a [prepared statement]. The first argument is the prepared statement 7681** object to be interrogated. The second argument 7682** is an integer code for a specific [SQLITE_STMTSTATUS counter] 7683** to be interrogated.)^ 7684** ^The current value of the requested counter is returned. 7685** ^If the resetFlg is true, then the counter is reset to zero after this 7686** interface call returns. 7687** 7688** See also: [sqlite3_status()] and [sqlite3_db_status()]. 7689*/ 7690int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 7691 7692/* 7693** CAPI3REF: Status Parameters for prepared statements 7694** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 7695** 7696** These preprocessor macros define integer codes that name counter 7697** values associated with the [sqlite3_stmt_status()] interface. 7698** The meanings of the various counters are as follows: 7699** 7700** <dl> 7701** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 7702** <dd>^This is the number of times that SQLite has stepped forward in 7703** a table as part of a full table scan. Large numbers for this counter 7704** may indicate opportunities for performance improvement through 7705** careful use of indices.</dd> 7706** 7707** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 7708** <dd>^This is the number of sort operations that have occurred. 7709** A non-zero value in this counter may indicate an opportunity to 7710** improvement performance through careful use of indices.</dd> 7711** 7712** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 7713** <dd>^This is the number of rows inserted into transient indices that 7714** were created automatically in order to help joins run faster. 7715** A non-zero value in this counter may indicate an opportunity to 7716** improvement performance by adding permanent indices that do not 7717** need to be reinitialized each time the statement is run.</dd> 7718** 7719** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 7720** <dd>^This is the number of virtual machine operations executed 7721** by the prepared statement if that number is less than or equal 7722** to 2147483647. The number of virtual machine operations can be 7723** used as a proxy for the total work done by the prepared statement. 7724** If the number of virtual machine operations exceeds 2147483647 7725** then the value returned by this statement status code is undefined. 7726** 7727** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 7728** <dd>^This is the number of times that the prepare statement has been 7729** automatically regenerated due to schema changes or change to 7730** [bound parameters] that might affect the query plan. 7731** 7732** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 7733** <dd>^This is the number of times that the prepared statement has 7734** been run. A single "run" for the purposes of this counter is one 7735** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 7736** The counter is incremented on the first [sqlite3_step()] call of each 7737** cycle. 7738** 7739** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 7740** <dd>^This is the approximate number of bytes of heap memory 7741** used to store the prepared statement. ^This value is not actually 7742** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 7743** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 7744** </dd> 7745** </dl> 7746*/ 7747#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 7748#define SQLITE_STMTSTATUS_SORT 2 7749#define SQLITE_STMTSTATUS_AUTOINDEX 3 7750#define SQLITE_STMTSTATUS_VM_STEP 4 7751#define SQLITE_STMTSTATUS_REPREPARE 5 7752#define SQLITE_STMTSTATUS_RUN 6 7753#define SQLITE_STMTSTATUS_MEMUSED 99 7754 7755/* 7756** CAPI3REF: Custom Page Cache Object 7757** 7758** The sqlite3_pcache type is opaque. It is implemented by 7759** the pluggable module. The SQLite core has no knowledge of 7760** its size or internal structure and never deals with the 7761** sqlite3_pcache object except by holding and passing pointers 7762** to the object. 7763** 7764** See [sqlite3_pcache_methods2] for additional information. 7765*/ 7766typedef struct sqlite3_pcache sqlite3_pcache; 7767 7768/* 7769** CAPI3REF: Custom Page Cache Object 7770** 7771** The sqlite3_pcache_page object represents a single page in the 7772** page cache. The page cache will allocate instances of this 7773** object. Various methods of the page cache use pointers to instances 7774** of this object as parameters or as their return value. 7775** 7776** See [sqlite3_pcache_methods2] for additional information. 7777*/ 7778typedef struct sqlite3_pcache_page sqlite3_pcache_page; 7779struct sqlite3_pcache_page { 7780 void *pBuf; /* The content of the page */ 7781 void *pExtra; /* Extra information associated with the page */ 7782}; 7783 7784/* 7785** CAPI3REF: Application Defined Page Cache. 7786** KEYWORDS: {page cache} 7787** 7788** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 7789** register an alternative page cache implementation by passing in an 7790** instance of the sqlite3_pcache_methods2 structure.)^ 7791** In many applications, most of the heap memory allocated by 7792** SQLite is used for the page cache. 7793** By implementing a 7794** custom page cache using this API, an application can better control 7795** the amount of memory consumed by SQLite, the way in which 7796** that memory is allocated and released, and the policies used to 7797** determine exactly which parts of a database file are cached and for 7798** how long. 7799** 7800** The alternative page cache mechanism is an 7801** extreme measure that is only needed by the most demanding applications. 7802** The built-in page cache is recommended for most uses. 7803** 7804** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 7805** internal buffer by SQLite within the call to [sqlite3_config]. Hence 7806** the application may discard the parameter after the call to 7807** [sqlite3_config()] returns.)^ 7808** 7809** [[the xInit() page cache method]] 7810** ^(The xInit() method is called once for each effective 7811** call to [sqlite3_initialize()])^ 7812** (usually only once during the lifetime of the process). ^(The xInit() 7813** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 7814** The intent of the xInit() method is to set up global data structures 7815** required by the custom page cache implementation. 7816** ^(If the xInit() method is NULL, then the 7817** built-in default page cache is used instead of the application defined 7818** page cache.)^ 7819** 7820** [[the xShutdown() page cache method]] 7821** ^The xShutdown() method is called by [sqlite3_shutdown()]. 7822** It can be used to clean up 7823** any outstanding resources before process shutdown, if required. 7824** ^The xShutdown() method may be NULL. 7825** 7826** ^SQLite automatically serializes calls to the xInit method, 7827** so the xInit method need not be threadsafe. ^The 7828** xShutdown method is only called from [sqlite3_shutdown()] so it does 7829** not need to be threadsafe either. All other methods must be threadsafe 7830** in multithreaded applications. 7831** 7832** ^SQLite will never invoke xInit() more than once without an intervening 7833** call to xShutdown(). 7834** 7835** [[the xCreate() page cache methods]] 7836** ^SQLite invokes the xCreate() method to construct a new cache instance. 7837** SQLite will typically create one cache instance for each open database file, 7838** though this is not guaranteed. ^The 7839** first parameter, szPage, is the size in bytes of the pages that must 7840** be allocated by the cache. ^szPage will always a power of two. ^The 7841** second parameter szExtra is a number of bytes of extra storage 7842** associated with each page cache entry. ^The szExtra parameter will 7843** a number less than 250. SQLite will use the 7844** extra szExtra bytes on each page to store metadata about the underlying 7845** database page on disk. The value passed into szExtra depends 7846** on the SQLite version, the target platform, and how SQLite was compiled. 7847** ^The third argument to xCreate(), bPurgeable, is true if the cache being 7848** created will be used to cache database pages of a file stored on disk, or 7849** false if it is used for an in-memory database. The cache implementation 7850** does not have to do anything special based with the value of bPurgeable; 7851** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 7852** never invoke xUnpin() except to deliberately delete a page. 7853** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 7854** false will always have the "discard" flag set to true. 7855** ^Hence, a cache created with bPurgeable false will 7856** never contain any unpinned pages. 7857** 7858** [[the xCachesize() page cache method]] 7859** ^(The xCachesize() method may be called at any time by SQLite to set the 7860** suggested maximum cache-size (number of pages stored by) the cache 7861** instance passed as the first argument. This is the value configured using 7862** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 7863** parameter, the implementation is not required to do anything with this 7864** value; it is advisory only. 7865** 7866** [[the xPagecount() page cache methods]] 7867** The xPagecount() method must return the number of pages currently 7868** stored in the cache, both pinned and unpinned. 7869** 7870** [[the xFetch() page cache methods]] 7871** The xFetch() method locates a page in the cache and returns a pointer to 7872** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 7873** The pBuf element of the returned sqlite3_pcache_page object will be a 7874** pointer to a buffer of szPage bytes used to store the content of a 7875** single database page. The pExtra element of sqlite3_pcache_page will be 7876** a pointer to the szExtra bytes of extra storage that SQLite has requested 7877** for each entry in the page cache. 7878** 7879** The page to be fetched is determined by the key. ^The minimum key value 7880** is 1. After it has been retrieved using xFetch, the page is considered 7881** to be "pinned". 7882** 7883** If the requested page is already in the page cache, then the page cache 7884** implementation must return a pointer to the page buffer with its content 7885** intact. If the requested page is not already in the cache, then the 7886** cache implementation should use the value of the createFlag 7887** parameter to help it determined what action to take: 7888** 7889** <table border=1 width=85% align=center> 7890** <tr><th> createFlag <th> Behavior when page is not already in cache 7891** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 7892** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 7893** Otherwise return NULL. 7894** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 7895** NULL if allocating a new page is effectively impossible. 7896** </table> 7897** 7898** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 7899** will only use a createFlag of 2 after a prior call with a createFlag of 1 7900** failed.)^ In between the to xFetch() calls, SQLite may 7901** attempt to unpin one or more cache pages by spilling the content of 7902** pinned pages to disk and synching the operating system disk cache. 7903** 7904** [[the xUnpin() page cache method]] 7905** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 7906** as its second argument. If the third parameter, discard, is non-zero, 7907** then the page must be evicted from the cache. 7908** ^If the discard parameter is 7909** zero, then the page may be discarded or retained at the discretion of 7910** page cache implementation. ^The page cache implementation 7911** may choose to evict unpinned pages at any time. 7912** 7913** The cache must not perform any reference counting. A single 7914** call to xUnpin() unpins the page regardless of the number of prior calls 7915** to xFetch(). 7916** 7917** [[the xRekey() page cache methods]] 7918** The xRekey() method is used to change the key value associated with the 7919** page passed as the second argument. If the cache 7920** previously contains an entry associated with newKey, it must be 7921** discarded. ^Any prior cache entry associated with newKey is guaranteed not 7922** to be pinned. 7923** 7924** When SQLite calls the xTruncate() method, the cache must discard all 7925** existing cache entries with page numbers (keys) greater than or equal 7926** to the value of the iLimit parameter passed to xTruncate(). If any 7927** of these pages are pinned, they are implicitly unpinned, meaning that 7928** they can be safely discarded. 7929** 7930** [[the xDestroy() page cache method]] 7931** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 7932** All resources associated with the specified cache should be freed. ^After 7933** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 7934** handle invalid, and will not use it with any other sqlite3_pcache_methods2 7935** functions. 7936** 7937** [[the xShrink() page cache method]] 7938** ^SQLite invokes the xShrink() method when it wants the page cache to 7939** free up as much of heap memory as possible. The page cache implementation 7940** is not obligated to free any memory, but well-behaved implementations should 7941** do their best. 7942*/ 7943typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 7944struct sqlite3_pcache_methods2 { 7945 int iVersion; 7946 void *pArg; 7947 int (*xInit)(void*); 7948 void (*xShutdown)(void*); 7949 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 7950 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7951 int (*xPagecount)(sqlite3_pcache*); 7952 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7953 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 7954 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 7955 unsigned oldKey, unsigned newKey); 7956 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7957 void (*xDestroy)(sqlite3_pcache*); 7958 void (*xShrink)(sqlite3_pcache*); 7959}; 7960 7961/* 7962** This is the obsolete pcache_methods object that has now been replaced 7963** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 7964** retained in the header file for backwards compatibility only. 7965*/ 7966typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 7967struct sqlite3_pcache_methods { 7968 void *pArg; 7969 int (*xInit)(void*); 7970 void (*xShutdown)(void*); 7971 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 7972 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7973 int (*xPagecount)(sqlite3_pcache*); 7974 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7975 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 7976 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 7977 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7978 void (*xDestroy)(sqlite3_pcache*); 7979}; 7980 7981 7982/* 7983** CAPI3REF: Online Backup Object 7984** 7985** The sqlite3_backup object records state information about an ongoing 7986** online backup operation. ^The sqlite3_backup object is created by 7987** a call to [sqlite3_backup_init()] and is destroyed by a call to 7988** [sqlite3_backup_finish()]. 7989** 7990** See Also: [Using the SQLite Online Backup API] 7991*/ 7992typedef struct sqlite3_backup sqlite3_backup; 7993 7994/* 7995** CAPI3REF: Online Backup API. 7996** 7997** The backup API copies the content of one database into another. 7998** It is useful either for creating backups of databases or 7999** for copying in-memory databases to or from persistent files. 8000** 8001** See Also: [Using the SQLite Online Backup API] 8002** 8003** ^SQLite holds a write transaction open on the destination database file 8004** for the duration of the backup operation. 8005** ^The source database is read-locked only while it is being read; 8006** it is not locked continuously for the entire backup operation. 8007** ^Thus, the backup may be performed on a live source database without 8008** preventing other database connections from 8009** reading or writing to the source database while the backup is underway. 8010** 8011** ^(To perform a backup operation: 8012** <ol> 8013** <li><b>sqlite3_backup_init()</b> is called once to initialize the 8014** backup, 8015** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 8016** the data between the two databases, and finally 8017** <li><b>sqlite3_backup_finish()</b> is called to release all resources 8018** associated with the backup operation. 8019** </ol>)^ 8020** There should be exactly one call to sqlite3_backup_finish() for each 8021** successful call to sqlite3_backup_init(). 8022** 8023** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 8024** 8025** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 8026** [database connection] associated with the destination database 8027** and the database name, respectively. 8028** ^The database name is "main" for the main database, "temp" for the 8029** temporary database, or the name specified after the AS keyword in 8030** an [ATTACH] statement for an attached database. 8031** ^The S and M arguments passed to 8032** sqlite3_backup_init(D,N,S,M) identify the [database connection] 8033** and database name of the source database, respectively. 8034** ^The source and destination [database connections] (parameters S and D) 8035** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 8036** an error. 8037** 8038** ^A call to sqlite3_backup_init() will fail, returning NULL, if 8039** there is already a read or read-write transaction open on the 8040** destination database. 8041** 8042** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 8043** returned and an error code and error message are stored in the 8044** destination [database connection] D. 8045** ^The error code and message for the failed call to sqlite3_backup_init() 8046** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 8047** [sqlite3_errmsg16()] functions. 8048** ^A successful call to sqlite3_backup_init() returns a pointer to an 8049** [sqlite3_backup] object. 8050** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 8051** sqlite3_backup_finish() functions to perform the specified backup 8052** operation. 8053** 8054** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 8055** 8056** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 8057** the source and destination databases specified by [sqlite3_backup] object B. 8058** ^If N is negative, all remaining source pages are copied. 8059** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 8060** are still more pages to be copied, then the function returns [SQLITE_OK]. 8061** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 8062** from source to destination, then it returns [SQLITE_DONE]. 8063** ^If an error occurs while running sqlite3_backup_step(B,N), 8064** then an [error code] is returned. ^As well as [SQLITE_OK] and 8065** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 8066** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 8067** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 8068** 8069** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 8070** <ol> 8071** <li> the destination database was opened read-only, or 8072** <li> the destination database is using write-ahead-log journaling 8073** and the destination and source page sizes differ, or 8074** <li> the destination database is an in-memory database and the 8075** destination and source page sizes differ. 8076** </ol>)^ 8077** 8078** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 8079** the [sqlite3_busy_handler | busy-handler function] 8080** is invoked (if one is specified). ^If the 8081** busy-handler returns non-zero before the lock is available, then 8082** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 8083** sqlite3_backup_step() can be retried later. ^If the source 8084** [database connection] 8085** is being used to write to the source database when sqlite3_backup_step() 8086** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 8087** case the call to sqlite3_backup_step() can be retried later on. ^(If 8088** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 8089** [SQLITE_READONLY] is returned, then 8090** there is no point in retrying the call to sqlite3_backup_step(). These 8091** errors are considered fatal.)^ The application must accept 8092** that the backup operation has failed and pass the backup operation handle 8093** to the sqlite3_backup_finish() to release associated resources. 8094** 8095** ^The first call to sqlite3_backup_step() obtains an exclusive lock 8096** on the destination file. ^The exclusive lock is not released until either 8097** sqlite3_backup_finish() is called or the backup operation is complete 8098** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 8099** sqlite3_backup_step() obtains a [shared lock] on the source database that 8100** lasts for the duration of the sqlite3_backup_step() call. 8101** ^Because the source database is not locked between calls to 8102** sqlite3_backup_step(), the source database may be modified mid-way 8103** through the backup process. ^If the source database is modified by an 8104** external process or via a database connection other than the one being 8105** used by the backup operation, then the backup will be automatically 8106** restarted by the next call to sqlite3_backup_step(). ^If the source 8107** database is modified by the using the same database connection as is used 8108** by the backup operation, then the backup database is automatically 8109** updated at the same time. 8110** 8111** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 8112** 8113** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 8114** application wishes to abandon the backup operation, the application 8115** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 8116** ^The sqlite3_backup_finish() interfaces releases all 8117** resources associated with the [sqlite3_backup] object. 8118** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 8119** active write-transaction on the destination database is rolled back. 8120** The [sqlite3_backup] object is invalid 8121** and may not be used following a call to sqlite3_backup_finish(). 8122** 8123** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 8124** sqlite3_backup_step() errors occurred, regardless or whether or not 8125** sqlite3_backup_step() completed. 8126** ^If an out-of-memory condition or IO error occurred during any prior 8127** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 8128** sqlite3_backup_finish() returns the corresponding [error code]. 8129** 8130** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 8131** is not a permanent error and does not affect the return value of 8132** sqlite3_backup_finish(). 8133** 8134** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 8135** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 8136** 8137** ^The sqlite3_backup_remaining() routine returns the number of pages still 8138** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 8139** ^The sqlite3_backup_pagecount() routine returns the total number of pages 8140** in the source database at the conclusion of the most recent 8141** sqlite3_backup_step(). 8142** ^(The values returned by these functions are only updated by 8143** sqlite3_backup_step(). If the source database is modified in a way that 8144** changes the size of the source database or the number of pages remaining, 8145** those changes are not reflected in the output of sqlite3_backup_pagecount() 8146** and sqlite3_backup_remaining() until after the next 8147** sqlite3_backup_step().)^ 8148** 8149** <b>Concurrent Usage of Database Handles</b> 8150** 8151** ^The source [database connection] may be used by the application for other 8152** purposes while a backup operation is underway or being initialized. 8153** ^If SQLite is compiled and configured to support threadsafe database 8154** connections, then the source database connection may be used concurrently 8155** from within other threads. 8156** 8157** However, the application must guarantee that the destination 8158** [database connection] is not passed to any other API (by any thread) after 8159** sqlite3_backup_init() is called and before the corresponding call to 8160** sqlite3_backup_finish(). SQLite does not currently check to see 8161** if the application incorrectly accesses the destination [database connection] 8162** and so no error code is reported, but the operations may malfunction 8163** nevertheless. Use of the destination database connection while a 8164** backup is in progress might also also cause a mutex deadlock. 8165** 8166** If running in [shared cache mode], the application must 8167** guarantee that the shared cache used by the destination database 8168** is not accessed while the backup is running. In practice this means 8169** that the application must guarantee that the disk file being 8170** backed up to is not accessed by any connection within the process, 8171** not just the specific connection that was passed to sqlite3_backup_init(). 8172** 8173** The [sqlite3_backup] object itself is partially threadsafe. Multiple 8174** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 8175** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 8176** APIs are not strictly speaking threadsafe. If they are invoked at the 8177** same time as another thread is invoking sqlite3_backup_step() it is 8178** possible that they return invalid values. 8179*/ 8180sqlite3_backup *sqlite3_backup_init( 8181 sqlite3 *pDest, /* Destination database handle */ 8182 const char *zDestName, /* Destination database name */ 8183 sqlite3 *pSource, /* Source database handle */ 8184 const char *zSourceName /* Source database name */ 8185); 8186int sqlite3_backup_step(sqlite3_backup *p, int nPage); 8187int sqlite3_backup_finish(sqlite3_backup *p); 8188int sqlite3_backup_remaining(sqlite3_backup *p); 8189int sqlite3_backup_pagecount(sqlite3_backup *p); 8190 8191/* 8192** CAPI3REF: Unlock Notification 8193** METHOD: sqlite3 8194** 8195** ^When running in shared-cache mode, a database operation may fail with 8196** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 8197** individual tables within the shared-cache cannot be obtained. See 8198** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 8199** ^This API may be used to register a callback that SQLite will invoke 8200** when the connection currently holding the required lock relinquishes it. 8201** ^This API is only available if the library was compiled with the 8202** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 8203** 8204** See Also: [Using the SQLite Unlock Notification Feature]. 8205** 8206** ^Shared-cache locks are released when a database connection concludes 8207** its current transaction, either by committing it or rolling it back. 8208** 8209** ^When a connection (known as the blocked connection) fails to obtain a 8210** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 8211** identity of the database connection (the blocking connection) that 8212** has locked the required resource is stored internally. ^After an 8213** application receives an SQLITE_LOCKED error, it may call the 8214** sqlite3_unlock_notify() method with the blocked connection handle as 8215** the first argument to register for a callback that will be invoked 8216** when the blocking connections current transaction is concluded. ^The 8217** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 8218** call that concludes the blocking connections transaction. 8219** 8220** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 8221** there is a chance that the blocking connection will have already 8222** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 8223** If this happens, then the specified callback is invoked immediately, 8224** from within the call to sqlite3_unlock_notify().)^ 8225** 8226** ^If the blocked connection is attempting to obtain a write-lock on a 8227** shared-cache table, and more than one other connection currently holds 8228** a read-lock on the same table, then SQLite arbitrarily selects one of 8229** the other connections to use as the blocking connection. 8230** 8231** ^(There may be at most one unlock-notify callback registered by a 8232** blocked connection. If sqlite3_unlock_notify() is called when the 8233** blocked connection already has a registered unlock-notify callback, 8234** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 8235** called with a NULL pointer as its second argument, then any existing 8236** unlock-notify callback is canceled. ^The blocked connections 8237** unlock-notify callback may also be canceled by closing the blocked 8238** connection using [sqlite3_close()]. 8239** 8240** The unlock-notify callback is not reentrant. If an application invokes 8241** any sqlite3_xxx API functions from within an unlock-notify callback, a 8242** crash or deadlock may be the result. 8243** 8244** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 8245** returns SQLITE_OK. 8246** 8247** <b>Callback Invocation Details</b> 8248** 8249** When an unlock-notify callback is registered, the application provides a 8250** single void* pointer that is passed to the callback when it is invoked. 8251** However, the signature of the callback function allows SQLite to pass 8252** it an array of void* context pointers. The first argument passed to 8253** an unlock-notify callback is a pointer to an array of void* pointers, 8254** and the second is the number of entries in the array. 8255** 8256** When a blocking connections transaction is concluded, there may be 8257** more than one blocked connection that has registered for an unlock-notify 8258** callback. ^If two or more such blocked connections have specified the 8259** same callback function, then instead of invoking the callback function 8260** multiple times, it is invoked once with the set of void* context pointers 8261** specified by the blocked connections bundled together into an array. 8262** This gives the application an opportunity to prioritize any actions 8263** related to the set of unblocked database connections. 8264** 8265** <b>Deadlock Detection</b> 8266** 8267** Assuming that after registering for an unlock-notify callback a 8268** database waits for the callback to be issued before taking any further 8269** action (a reasonable assumption), then using this API may cause the 8270** application to deadlock. For example, if connection X is waiting for 8271** connection Y's transaction to be concluded, and similarly connection 8272** Y is waiting on connection X's transaction, then neither connection 8273** will proceed and the system may remain deadlocked indefinitely. 8274** 8275** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 8276** detection. ^If a given call to sqlite3_unlock_notify() would put the 8277** system in a deadlocked state, then SQLITE_LOCKED is returned and no 8278** unlock-notify callback is registered. The system is said to be in 8279** a deadlocked state if connection A has registered for an unlock-notify 8280** callback on the conclusion of connection B's transaction, and connection 8281** B has itself registered for an unlock-notify callback when connection 8282** A's transaction is concluded. ^Indirect deadlock is also detected, so 8283** the system is also considered to be deadlocked if connection B has 8284** registered for an unlock-notify callback on the conclusion of connection 8285** C's transaction, where connection C is waiting on connection A. ^Any 8286** number of levels of indirection are allowed. 8287** 8288** <b>The "DROP TABLE" Exception</b> 8289** 8290** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 8291** always appropriate to call sqlite3_unlock_notify(). There is however, 8292** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 8293** SQLite checks if there are any currently executing SELECT statements 8294** that belong to the same connection. If there are, SQLITE_LOCKED is 8295** returned. In this case there is no "blocking connection", so invoking 8296** sqlite3_unlock_notify() results in the unlock-notify callback being 8297** invoked immediately. If the application then re-attempts the "DROP TABLE" 8298** or "DROP INDEX" query, an infinite loop might be the result. 8299** 8300** One way around this problem is to check the extended error code returned 8301** by an sqlite3_step() call. ^(If there is a blocking connection, then the 8302** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 8303** the special "DROP TABLE/INDEX" case, the extended error code is just 8304** SQLITE_LOCKED.)^ 8305*/ 8306int sqlite3_unlock_notify( 8307 sqlite3 *pBlocked, /* Waiting connection */ 8308 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 8309 void *pNotifyArg /* Argument to pass to xNotify */ 8310); 8311 8312 8313/* 8314** CAPI3REF: String Comparison 8315** 8316** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 8317** and extensions to compare the contents of two buffers containing UTF-8 8318** strings in a case-independent fashion, using the same definition of "case 8319** independence" that SQLite uses internally when comparing identifiers. 8320*/ 8321int sqlite3_stricmp(const char *, const char *); 8322int sqlite3_strnicmp(const char *, const char *, int); 8323 8324/* 8325** CAPI3REF: String Globbing 8326* 8327** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 8328** string X matches the [GLOB] pattern P. 8329** ^The definition of [GLOB] pattern matching used in 8330** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 8331** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 8332** is case sensitive. 8333** 8334** Note that this routine returns zero on a match and non-zero if the strings 8335** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8336** 8337** See also: [sqlite3_strlike()]. 8338*/ 8339int sqlite3_strglob(const char *zGlob, const char *zStr); 8340 8341/* 8342** CAPI3REF: String LIKE Matching 8343* 8344** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 8345** string X matches the [LIKE] pattern P with escape character E. 8346** ^The definition of [LIKE] pattern matching used in 8347** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 8348** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 8349** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 8350** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 8351** insensitive - equivalent upper and lower case ASCII characters match 8352** one another. 8353** 8354** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 8355** only ASCII characters are case folded. 8356** 8357** Note that this routine returns zero on a match and non-zero if the strings 8358** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8359** 8360** See also: [sqlite3_strglob()]. 8361*/ 8362int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 8363 8364/* 8365** CAPI3REF: Error Logging Interface 8366** 8367** ^The [sqlite3_log()] interface writes a message into the [error log] 8368** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 8369** ^If logging is enabled, the zFormat string and subsequent arguments are 8370** used with [sqlite3_snprintf()] to generate the final output string. 8371** 8372** The sqlite3_log() interface is intended for use by extensions such as 8373** virtual tables, collating functions, and SQL functions. While there is 8374** nothing to prevent an application from calling sqlite3_log(), doing so 8375** is considered bad form. 8376** 8377** The zFormat string must not be NULL. 8378** 8379** To avoid deadlocks and other threading problems, the sqlite3_log() routine 8380** will not use dynamically allocated memory. The log message is stored in 8381** a fixed-length buffer on the stack. If the log message is longer than 8382** a few hundred characters, it will be truncated to the length of the 8383** buffer. 8384*/ 8385void sqlite3_log(int iErrCode, const char *zFormat, ...); 8386 8387/* 8388** CAPI3REF: Write-Ahead Log Commit Hook 8389** METHOD: sqlite3 8390** 8391** ^The [sqlite3_wal_hook()] function is used to register a callback that 8392** is invoked each time data is committed to a database in wal mode. 8393** 8394** ^(The callback is invoked by SQLite after the commit has taken place and 8395** the associated write-lock on the database released)^, so the implementation 8396** may read, write or [checkpoint] the database as required. 8397** 8398** ^The first parameter passed to the callback function when it is invoked 8399** is a copy of the third parameter passed to sqlite3_wal_hook() when 8400** registering the callback. ^The second is a copy of the database handle. 8401** ^The third parameter is the name of the database that was written to - 8402** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 8403** is the number of pages currently in the write-ahead log file, 8404** including those that were just committed. 8405** 8406** The callback function should normally return [SQLITE_OK]. ^If an error 8407** code is returned, that error will propagate back up through the 8408** SQLite code base to cause the statement that provoked the callback 8409** to report an error, though the commit will have still occurred. If the 8410** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 8411** that does not correspond to any valid SQLite error code, the results 8412** are undefined. 8413** 8414** A single database handle may have at most a single write-ahead log callback 8415** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 8416** previously registered write-ahead log callback. ^Note that the 8417** [sqlite3_wal_autocheckpoint()] interface and the 8418** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 8419** overwrite any prior [sqlite3_wal_hook()] settings. 8420*/ 8421void *sqlite3_wal_hook( 8422 sqlite3*, 8423 int(*)(void *,sqlite3*,const char*,int), 8424 void* 8425); 8426 8427/* 8428** CAPI3REF: Configure an auto-checkpoint 8429** METHOD: sqlite3 8430** 8431** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 8432** [sqlite3_wal_hook()] that causes any database on [database connection] D 8433** to automatically [checkpoint] 8434** after committing a transaction if there are N or 8435** more frames in the [write-ahead log] file. ^Passing zero or 8436** a negative value as the nFrame parameter disables automatic 8437** checkpoints entirely. 8438** 8439** ^The callback registered by this function replaces any existing callback 8440** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 8441** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 8442** configured by this function. 8443** 8444** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 8445** from SQL. 8446** 8447** ^Checkpoints initiated by this mechanism are 8448** [sqlite3_wal_checkpoint_v2|PASSIVE]. 8449** 8450** ^Every new [database connection] defaults to having the auto-checkpoint 8451** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 8452** pages. The use of this interface 8453** is only necessary if the default setting is found to be suboptimal 8454** for a particular application. 8455*/ 8456int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 8457 8458/* 8459** CAPI3REF: Checkpoint a database 8460** METHOD: sqlite3 8461** 8462** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 8463** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 8464** 8465** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 8466** [write-ahead log] for database X on [database connection] D to be 8467** transferred into the database file and for the write-ahead log to 8468** be reset. See the [checkpointing] documentation for addition 8469** information. 8470** 8471** This interface used to be the only way to cause a checkpoint to 8472** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 8473** interface was added. This interface is retained for backwards 8474** compatibility and as a convenience for applications that need to manually 8475** start a callback but which do not need the full power (and corresponding 8476** complication) of [sqlite3_wal_checkpoint_v2()]. 8477*/ 8478int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 8479 8480/* 8481** CAPI3REF: Checkpoint a database 8482** METHOD: sqlite3 8483** 8484** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 8485** operation on database X of [database connection] D in mode M. Status 8486** information is written back into integers pointed to by L and C.)^ 8487** ^(The M parameter must be a valid [checkpoint mode]:)^ 8488** 8489** <dl> 8490** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 8491** ^Checkpoint as many frames as possible without waiting for any database 8492** readers or writers to finish, then sync the database file if all frames 8493** in the log were checkpointed. ^The [busy-handler callback] 8494** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 8495** ^On the other hand, passive mode might leave the checkpoint unfinished 8496** if there are concurrent readers or writers. 8497** 8498** <dt>SQLITE_CHECKPOINT_FULL<dd> 8499** ^This mode blocks (it invokes the 8500** [sqlite3_busy_handler|busy-handler callback]) until there is no 8501** database writer and all readers are reading from the most recent database 8502** snapshot. ^It then checkpoints all frames in the log file and syncs the 8503** database file. ^This mode blocks new database writers while it is pending, 8504** but new database readers are allowed to continue unimpeded. 8505** 8506** <dt>SQLITE_CHECKPOINT_RESTART<dd> 8507** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 8508** that after checkpointing the log file it blocks (calls the 8509** [busy-handler callback]) 8510** until all readers are reading from the database file only. ^This ensures 8511** that the next writer will restart the log file from the beginning. 8512** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 8513** database writer attempts while it is pending, but does not impede readers. 8514** 8515** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 8516** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 8517** addition that it also truncates the log file to zero bytes just prior 8518** to a successful return. 8519** </dl> 8520** 8521** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 8522** the log file or to -1 if the checkpoint could not run because 8523** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 8524** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 8525** log file (including any that were already checkpointed before the function 8526** was called) or to -1 if the checkpoint could not run due to an error or 8527** because the database is not in WAL mode. ^Note that upon successful 8528** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 8529** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 8530** 8531** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 8532** any other process is running a checkpoint operation at the same time, the 8533** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 8534** busy-handler configured, it will not be invoked in this case. 8535** 8536** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 8537** exclusive "writer" lock on the database file. ^If the writer lock cannot be 8538** obtained immediately, and a busy-handler is configured, it is invoked and 8539** the writer lock retried until either the busy-handler returns 0 or the lock 8540** is successfully obtained. ^The busy-handler is also invoked while waiting for 8541** database readers as described above. ^If the busy-handler returns 0 before 8542** the writer lock is obtained or while waiting for database readers, the 8543** checkpoint operation proceeds from that point in the same way as 8544** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 8545** without blocking any further. ^SQLITE_BUSY is returned in this case. 8546** 8547** ^If parameter zDb is NULL or points to a zero length string, then the 8548** specified operation is attempted on all WAL databases [attached] to 8549** [database connection] db. In this case the 8550** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 8551** an SQLITE_BUSY error is encountered when processing one or more of the 8552** attached WAL databases, the operation is still attempted on any remaining 8553** attached databases and SQLITE_BUSY is returned at the end. ^If any other 8554** error occurs while processing an attached database, processing is abandoned 8555** and the error code is returned to the caller immediately. ^If no error 8556** (SQLITE_BUSY or otherwise) is encountered while processing the attached 8557** databases, SQLITE_OK is returned. 8558** 8559** ^If database zDb is the name of an attached database that is not in WAL 8560** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 8561** zDb is not NULL (or a zero length string) and is not the name of any 8562** attached database, SQLITE_ERROR is returned to the caller. 8563** 8564** ^Unless it returns SQLITE_MISUSE, 8565** the sqlite3_wal_checkpoint_v2() interface 8566** sets the error information that is queried by 8567** [sqlite3_errcode()] and [sqlite3_errmsg()]. 8568** 8569** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 8570** from SQL. 8571*/ 8572int sqlite3_wal_checkpoint_v2( 8573 sqlite3 *db, /* Database handle */ 8574 const char *zDb, /* Name of attached database (or NULL) */ 8575 int eMode, /* SQLITE_CHECKPOINT_* value */ 8576 int *pnLog, /* OUT: Size of WAL log in frames */ 8577 int *pnCkpt /* OUT: Total number of frames checkpointed */ 8578); 8579 8580/* 8581** CAPI3REF: Checkpoint Mode Values 8582** KEYWORDS: {checkpoint mode} 8583** 8584** These constants define all valid values for the "checkpoint mode" passed 8585** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 8586** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 8587** meaning of each of these checkpoint modes. 8588*/ 8589#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 8590#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 8591#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 8592#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 8593 8594/* 8595** CAPI3REF: Virtual Table Interface Configuration 8596** 8597** This function may be called by either the [xConnect] or [xCreate] method 8598** of a [virtual table] implementation to configure 8599** various facets of the virtual table interface. 8600** 8601** If this interface is invoked outside the context of an xConnect or 8602** xCreate virtual table method then the behavior is undefined. 8603** 8604** At present, there is only one option that may be configured using 8605** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 8606** may be added in the future. 8607*/ 8608int sqlite3_vtab_config(sqlite3*, int op, ...); 8609 8610/* 8611** CAPI3REF: Virtual Table Configuration Options 8612** 8613** These macros define the various options to the 8614** [sqlite3_vtab_config()] interface that [virtual table] implementations 8615** can use to customize and optimize their behavior. 8616** 8617** <dl> 8618** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 8619** <dd>Calls of the form 8620** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 8621** where X is an integer. If X is zero, then the [virtual table] whose 8622** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 8623** support constraints. In this configuration (which is the default) if 8624** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 8625** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 8626** specified as part of the users SQL statement, regardless of the actual 8627** ON CONFLICT mode specified. 8628** 8629** If X is non-zero, then the virtual table implementation guarantees 8630** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 8631** any modifications to internal or persistent data structures have been made. 8632** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 8633** is able to roll back a statement or database transaction, and abandon 8634** or continue processing the current SQL statement as appropriate. 8635** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 8636** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 8637** had been ABORT. 8638** 8639** Virtual table implementations that are required to handle OR REPLACE 8640** must do so within the [xUpdate] method. If a call to the 8641** [sqlite3_vtab_on_conflict()] function indicates that the current ON 8642** CONFLICT policy is REPLACE, the virtual table implementation should 8643** silently replace the appropriate rows within the xUpdate callback and 8644** return SQLITE_OK. Or, if this is not possible, it may return 8645** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 8646** constraint handling. 8647** </dl> 8648*/ 8649#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 8650 8651/* 8652** CAPI3REF: Determine The Virtual Table Conflict Policy 8653** 8654** This function may only be called from within a call to the [xUpdate] method 8655** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 8656** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 8657** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 8658** of the SQL statement that triggered the call to the [xUpdate] method of the 8659** [virtual table]. 8660*/ 8661int sqlite3_vtab_on_conflict(sqlite3 *); 8662 8663/* 8664** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE 8665** 8666** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn] 8667** method of a [virtual table], then it returns true if and only if the 8668** column is being fetched as part of an UPDATE operation during which the 8669** column value will not change. Applications might use this to substitute 8670** a return value that is less expensive to compute and that the corresponding 8671** [xUpdate] method understands as a "no-change" value. 8672** 8673** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that 8674** the column is not changed by the UPDATE statement, then the xColumn 8675** method can optionally return without setting a result, without calling 8676** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces]. 8677** In that case, [sqlite3_value_nochange(X)] will return true for the 8678** same column in the [xUpdate] method. 8679*/ 8680int sqlite3_vtab_nochange(sqlite3_context*); 8681 8682/* 8683** CAPI3REF: Determine The Collation For a Virtual Table Constraint 8684** 8685** This function may only be called from within a call to the [xBestIndex] 8686** method of a [virtual table]. 8687** 8688** The first argument must be the sqlite3_index_info object that is the 8689** first parameter to the xBestIndex() method. The second argument must be 8690** an index into the aConstraint[] array belonging to the sqlite3_index_info 8691** structure passed to xBestIndex. This function returns a pointer to a buffer 8692** containing the name of the collation sequence for the corresponding 8693** constraint. 8694*/ 8695SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int); 8696 8697/* 8698** CAPI3REF: Conflict resolution modes 8699** KEYWORDS: {conflict resolution mode} 8700** 8701** These constants are returned by [sqlite3_vtab_on_conflict()] to 8702** inform a [virtual table] implementation what the [ON CONFLICT] mode 8703** is for the SQL statement being evaluated. 8704** 8705** Note that the [SQLITE_IGNORE] constant is also used as a potential 8706** return value from the [sqlite3_set_authorizer()] callback and that 8707** [SQLITE_ABORT] is also a [result code]. 8708*/ 8709#define SQLITE_ROLLBACK 1 8710/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 8711#define SQLITE_FAIL 3 8712/* #define SQLITE_ABORT 4 // Also an error code */ 8713#define SQLITE_REPLACE 5 8714 8715/* 8716** CAPI3REF: Prepared Statement Scan Status Opcodes 8717** KEYWORDS: {scanstatus options} 8718** 8719** The following constants can be used for the T parameter to the 8720** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 8721** different metric for sqlite3_stmt_scanstatus() to return. 8722** 8723** When the value returned to V is a string, space to hold that string is 8724** managed by the prepared statement S and will be automatically freed when 8725** S is finalized. 8726** 8727** <dl> 8728** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 8729** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 8730** set to the total number of times that the X-th loop has run.</dd> 8731** 8732** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 8733** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 8734** to the total number of rows examined by all iterations of the X-th loop.</dd> 8735** 8736** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 8737** <dd>^The "double" variable pointed to by the T parameter will be set to the 8738** query planner's estimate for the average number of rows output from each 8739** iteration of the X-th loop. If the query planner's estimates was accurate, 8740** then this value will approximate the quotient NVISIT/NLOOP and the 8741** product of this value for all prior loops with the same SELECTID will 8742** be the NLOOP value for the current loop. 8743** 8744** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 8745** <dd>^The "const char *" variable pointed to by the T parameter will be set 8746** to a zero-terminated UTF-8 string containing the name of the index or table 8747** used for the X-th loop. 8748** 8749** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 8750** <dd>^The "const char *" variable pointed to by the T parameter will be set 8751** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 8752** description for the X-th loop. 8753** 8754** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 8755** <dd>^The "int" variable pointed to by the T parameter will be set to the 8756** "select-id" for the X-th loop. The select-id identifies which query or 8757** subquery the loop is part of. The main query has a select-id of zero. 8758** The select-id is the same value as is output in the first column 8759** of an [EXPLAIN QUERY PLAN] query. 8760** </dl> 8761*/ 8762#define SQLITE_SCANSTAT_NLOOP 0 8763#define SQLITE_SCANSTAT_NVISIT 1 8764#define SQLITE_SCANSTAT_EST 2 8765#define SQLITE_SCANSTAT_NAME 3 8766#define SQLITE_SCANSTAT_EXPLAIN 4 8767#define SQLITE_SCANSTAT_SELECTID 5 8768 8769/* 8770** CAPI3REF: Prepared Statement Scan Status 8771** METHOD: sqlite3_stmt 8772** 8773** This interface returns information about the predicted and measured 8774** performance for pStmt. Advanced applications can use this 8775** interface to compare the predicted and the measured performance and 8776** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 8777** 8778** Since this interface is expected to be rarely used, it is only 8779** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 8780** compile-time option. 8781** 8782** The "iScanStatusOp" parameter determines which status information to return. 8783** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 8784** of this interface is undefined. 8785** ^The requested measurement is written into a variable pointed to by 8786** the "pOut" parameter. 8787** Parameter "idx" identifies the specific loop to retrieve statistics for. 8788** Loops are numbered starting from zero. ^If idx is out of range - less than 8789** zero or greater than or equal to the total number of loops used to implement 8790** the statement - a non-zero value is returned and the variable that pOut 8791** points to is unchanged. 8792** 8793** ^Statistics might not be available for all loops in all statements. ^In cases 8794** where there exist loops with no available statistics, this function behaves 8795** as if the loop did not exist - it returns non-zero and leave the variable 8796** that pOut points to unchanged. 8797** 8798** See also: [sqlite3_stmt_scanstatus_reset()] 8799*/ 8800int sqlite3_stmt_scanstatus( 8801 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 8802 int idx, /* Index of loop to report on */ 8803 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 8804 void *pOut /* Result written here */ 8805); 8806 8807/* 8808** CAPI3REF: Zero Scan-Status Counters 8809** METHOD: sqlite3_stmt 8810** 8811** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 8812** 8813** This API is only available if the library is built with pre-processor 8814** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 8815*/ 8816void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 8817 8818/* 8819** CAPI3REF: Flush caches to disk mid-transaction 8820** 8821** ^If a write-transaction is open on [database connection] D when the 8822** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 8823** pages in the pager-cache that are not currently in use are written out 8824** to disk. A dirty page may be in use if a database cursor created by an 8825** active SQL statement is reading from it, or if it is page 1 of a database 8826** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 8827** interface flushes caches for all schemas - "main", "temp", and 8828** any [attached] databases. 8829** 8830** ^If this function needs to obtain extra database locks before dirty pages 8831** can be flushed to disk, it does so. ^If those locks cannot be obtained 8832** immediately and there is a busy-handler callback configured, it is invoked 8833** in the usual manner. ^If the required lock still cannot be obtained, then 8834** the database is skipped and an attempt made to flush any dirty pages 8835** belonging to the next (if any) database. ^If any databases are skipped 8836** because locks cannot be obtained, but no other error occurs, this 8837** function returns SQLITE_BUSY. 8838** 8839** ^If any other error occurs while flushing dirty pages to disk (for 8840** example an IO error or out-of-memory condition), then processing is 8841** abandoned and an SQLite [error code] is returned to the caller immediately. 8842** 8843** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 8844** 8845** ^This function does not set the database handle error code or message 8846** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 8847*/ 8848int sqlite3_db_cacheflush(sqlite3*); 8849 8850/* 8851** CAPI3REF: The pre-update hook. 8852** 8853** ^These interfaces are only available if SQLite is compiled using the 8854** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 8855** 8856** ^The [sqlite3_preupdate_hook()] interface registers a callback function 8857** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 8858** on a database table. 8859** ^At most one preupdate hook may be registered at a time on a single 8860** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 8861** the previous setting. 8862** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 8863** with a NULL pointer as the second parameter. 8864** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 8865** the first parameter to callbacks. 8866** 8867** ^The preupdate hook only fires for changes to real database tables; the 8868** preupdate hook is not invoked for changes to [virtual tables] or to 8869** system tables like sqlite_master or sqlite_stat1. 8870** 8871** ^The second parameter to the preupdate callback is a pointer to 8872** the [database connection] that registered the preupdate hook. 8873** ^The third parameter to the preupdate callback is one of the constants 8874** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 8875** kind of update operation that is about to occur. 8876** ^(The fourth parameter to the preupdate callback is the name of the 8877** database within the database connection that is being modified. This 8878** will be "main" for the main database or "temp" for TEMP tables or 8879** the name given after the AS keyword in the [ATTACH] statement for attached 8880** databases.)^ 8881** ^The fifth parameter to the preupdate callback is the name of the 8882** table that is being modified. 8883** 8884** For an UPDATE or DELETE operation on a [rowid table], the sixth 8885** parameter passed to the preupdate callback is the initial [rowid] of the 8886** row being modified or deleted. For an INSERT operation on a rowid table, 8887** or any operation on a WITHOUT ROWID table, the value of the sixth 8888** parameter is undefined. For an INSERT or UPDATE on a rowid table the 8889** seventh parameter is the final rowid value of the row being inserted 8890** or updated. The value of the seventh parameter passed to the callback 8891** function is not defined for operations on WITHOUT ROWID tables, or for 8892** INSERT operations on rowid tables. 8893** 8894** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 8895** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 8896** provide additional information about a preupdate event. These routines 8897** may only be called from within a preupdate callback. Invoking any of 8898** these routines from outside of a preupdate callback or with a 8899** [database connection] pointer that is different from the one supplied 8900** to the preupdate callback results in undefined and probably undesirable 8901** behavior. 8902** 8903** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 8904** in the row that is being inserted, updated, or deleted. 8905** 8906** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 8907** a [protected sqlite3_value] that contains the value of the Nth column of 8908** the table row before it is updated. The N parameter must be between 0 8909** and one less than the number of columns or the behavior will be 8910** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 8911** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 8912** behavior is undefined. The [sqlite3_value] that P points to 8913** will be destroyed when the preupdate callback returns. 8914** 8915** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 8916** a [protected sqlite3_value] that contains the value of the Nth column of 8917** the table row after it is updated. The N parameter must be between 0 8918** and one less than the number of columns or the behavior will be 8919** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 8920** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 8921** behavior is undefined. The [sqlite3_value] that P points to 8922** will be destroyed when the preupdate callback returns. 8923** 8924** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 8925** callback was invoked as a result of a direct insert, update, or delete 8926** operation; or 1 for inserts, updates, or deletes invoked by top-level 8927** triggers; or 2 for changes resulting from triggers called by top-level 8928** triggers; and so forth. 8929** 8930** See also: [sqlite3_update_hook()] 8931*/ 8932#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 8933void *sqlite3_preupdate_hook( 8934 sqlite3 *db, 8935 void(*xPreUpdate)( 8936 void *pCtx, /* Copy of third arg to preupdate_hook() */ 8937 sqlite3 *db, /* Database handle */ 8938 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 8939 char const *zDb, /* Database name */ 8940 char const *zName, /* Table name */ 8941 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 8942 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 8943 ), 8944 void* 8945); 8946int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 8947int sqlite3_preupdate_count(sqlite3 *); 8948int sqlite3_preupdate_depth(sqlite3 *); 8949int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 8950#endif 8951 8952/* 8953** CAPI3REF: Low-level system error code 8954** 8955** ^Attempt to return the underlying operating system error code or error 8956** number that caused the most recent I/O error or failure to open a file. 8957** The return value is OS-dependent. For example, on unix systems, after 8958** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 8959** called to get back the underlying "errno" that caused the problem, such 8960** as ENOSPC, EAUTH, EISDIR, and so forth. 8961*/ 8962int sqlite3_system_errno(sqlite3*); 8963 8964/* 8965** CAPI3REF: Database Snapshot 8966** KEYWORDS: {snapshot} {sqlite3_snapshot} 8967** 8968** An instance of the snapshot object records the state of a [WAL mode] 8969** database for some specific point in history. 8970** 8971** In [WAL mode], multiple [database connections] that are open on the 8972** same database file can each be reading a different historical version 8973** of the database file. When a [database connection] begins a read 8974** transaction, that connection sees an unchanging copy of the database 8975** as it existed for the point in time when the transaction first started. 8976** Subsequent changes to the database from other connections are not seen 8977** by the reader until a new read transaction is started. 8978** 8979** The sqlite3_snapshot object records state information about an historical 8980** version of the database file so that it is possible to later open a new read 8981** transaction that sees that historical version of the database rather than 8982** the most recent version. 8983*/ 8984typedef struct sqlite3_snapshot { 8985 unsigned char hidden[48]; 8986} sqlite3_snapshot; 8987 8988/* 8989** CAPI3REF: Record A Database Snapshot 8990** CONSTRUCTOR: sqlite3_snapshot 8991** 8992** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 8993** new [sqlite3_snapshot] object that records the current state of 8994** schema S in database connection D. ^On success, the 8995** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 8996** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 8997** If there is not already a read-transaction open on schema S when 8998** this function is called, one is opened automatically. 8999** 9000** The following must be true for this function to succeed. If any of 9001** the following statements are false when sqlite3_snapshot_get() is 9002** called, SQLITE_ERROR is returned. The final value of *P is undefined 9003** in this case. 9004** 9005** <ul> 9006** <li> The database handle must not be in [autocommit mode]. 9007** 9008** <li> Schema S of [database connection] D must be a [WAL mode] database. 9009** 9010** <li> There must not be a write transaction open on schema S of database 9011** connection D. 9012** 9013** <li> One or more transactions must have been written to the current wal 9014** file since it was created on disk (by any connection). This means 9015** that a snapshot cannot be taken on a wal mode database with no wal 9016** file immediately after it is first opened. At least one transaction 9017** must be written to it first. 9018** </ul> 9019** 9020** This function may also return SQLITE_NOMEM. If it is called with the 9021** database handle in autocommit mode but fails for some other reason, 9022** whether or not a read transaction is opened on schema S is undefined. 9023** 9024** The [sqlite3_snapshot] object returned from a successful call to 9025** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 9026** to avoid a memory leak. 9027** 9028** The [sqlite3_snapshot_get()] interface is only available when the 9029** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9030*/ 9031SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 9032 sqlite3 *db, 9033 const char *zSchema, 9034 sqlite3_snapshot **ppSnapshot 9035); 9036 9037/* 9038** CAPI3REF: Start a read transaction on an historical snapshot 9039** METHOD: sqlite3_snapshot 9040** 9041** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read 9042** transaction or upgrades an existing one for schema S of 9043** [database connection] D such that the read transaction refers to 9044** historical [snapshot] P, rather than the most recent change to the 9045** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK 9046** on success or an appropriate [error code] if it fails. 9047** 9048** ^In order to succeed, the database connection must not be in 9049** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there 9050** is already a read transaction open on schema S, then the database handle 9051** must have no active statements (SELECT statements that have been passed 9052** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()). 9053** SQLITE_ERROR is returned if either of these conditions is violated, or 9054** if schema S does not exist, or if the snapshot object is invalid. 9055** 9056** ^A call to sqlite3_snapshot_open() will fail to open if the specified 9057** snapshot has been overwritten by a [checkpoint]. In this case 9058** SQLITE_ERROR_SNAPSHOT is returned. 9059** 9060** If there is already a read transaction open when this function is 9061** invoked, then the same read transaction remains open (on the same 9062** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT 9063** is returned. If another error code - for example SQLITE_PROTOCOL or an 9064** SQLITE_IOERR error code - is returned, then the final state of the 9065** read transaction is undefined. If SQLITE_OK is returned, then the 9066** read transaction is now open on database snapshot P. 9067** 9068** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 9069** database connection D does not know that the database file for 9070** schema S is in [WAL mode]. A database connection might not know 9071** that the database file is in [WAL mode] if there has been no prior 9072** I/O on that database connection, or if the database entered [WAL mode] 9073** after the most recent I/O on the database connection.)^ 9074** (Hint: Run "[PRAGMA application_id]" against a newly opened 9075** database connection in order to make it ready to use snapshots.) 9076** 9077** The [sqlite3_snapshot_open()] interface is only available when the 9078** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9079*/ 9080SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 9081 sqlite3 *db, 9082 const char *zSchema, 9083 sqlite3_snapshot *pSnapshot 9084); 9085 9086/* 9087** CAPI3REF: Destroy a snapshot 9088** DESTRUCTOR: sqlite3_snapshot 9089** 9090** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 9091** The application must eventually free every [sqlite3_snapshot] object 9092** using this routine to avoid a memory leak. 9093** 9094** The [sqlite3_snapshot_free()] interface is only available when the 9095** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9096*/ 9097SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 9098 9099/* 9100** CAPI3REF: Compare the ages of two snapshot handles. 9101** METHOD: sqlite3_snapshot 9102** 9103** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 9104** of two valid snapshot handles. 9105** 9106** If the two snapshot handles are not associated with the same database 9107** file, the result of the comparison is undefined. 9108** 9109** Additionally, the result of the comparison is only valid if both of the 9110** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 9111** last time the wal file was deleted. The wal file is deleted when the 9112** database is changed back to rollback mode or when the number of database 9113** clients drops to zero. If either snapshot handle was obtained before the 9114** wal file was last deleted, the value returned by this function 9115** is undefined. 9116** 9117** Otherwise, this API returns a negative value if P1 refers to an older 9118** snapshot than P2, zero if the two handles refer to the same database 9119** snapshot, and a positive value if P1 is a newer snapshot than P2. 9120** 9121** This interface is only available if SQLite is compiled with the 9122** [SQLITE_ENABLE_SNAPSHOT] option. 9123*/ 9124SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 9125 sqlite3_snapshot *p1, 9126 sqlite3_snapshot *p2 9127); 9128 9129/* 9130** CAPI3REF: Recover snapshots from a wal file 9131** METHOD: sqlite3_snapshot 9132** 9133** If a [WAL file] remains on disk after all database connections close 9134** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control] 9135** or because the last process to have the database opened exited without 9136** calling [sqlite3_close()]) and a new connection is subsequently opened 9137** on that database and [WAL file], the [sqlite3_snapshot_open()] interface 9138** will only be able to open the last transaction added to the WAL file 9139** even though the WAL file contains other valid transactions. 9140** 9141** This function attempts to scan the WAL file associated with database zDb 9142** of database handle db and make all valid snapshots available to 9143** sqlite3_snapshot_open(). It is an error if there is already a read 9144** transaction open on the database, or if the database is not a WAL mode 9145** database. 9146** 9147** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 9148** 9149** This interface is only available if SQLite is compiled with the 9150** [SQLITE_ENABLE_SNAPSHOT] option. 9151*/ 9152SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 9153 9154/* 9155** CAPI3REF: Serialize a database 9156** 9157** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory 9158** that is a serialization of the S database on [database connection] D. 9159** If P is not a NULL pointer, then the size of the database in bytes 9160** is written into *P. 9161** 9162** For an ordinary on-disk database file, the serialization is just a 9163** copy of the disk file. For an in-memory database or a "TEMP" database, 9164** the serialization is the same sequence of bytes which would be written 9165** to disk if that database where backed up to disk. 9166** 9167** The usual case is that sqlite3_serialize() copies the serialization of 9168** the database into memory obtained from [sqlite3_malloc64()] and returns 9169** a pointer to that memory. The caller is responsible for freeing the 9170** returned value to avoid a memory leak. However, if the F argument 9171** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations 9172** are made, and the sqlite3_serialize() function will return a pointer 9173** to the contiguous memory representation of the database that SQLite 9174** is currently using for that database, or NULL if the no such contiguous 9175** memory representation of the database exists. A contiguous memory 9176** representation of the database will usually only exist if there has 9177** been a prior call to [sqlite3_deserialize(D,S,...)] with the same 9178** values of D and S. 9179** The size of the database is written into *P even if the 9180** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy 9181** of the database exists. 9182** 9183** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the 9184** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory 9185** allocation error occurs. 9186** 9187** This interface is only available if SQLite is compiled with the 9188** [SQLITE_ENABLE_DESERIALIZE] option. 9189*/ 9190unsigned char *sqlite3_serialize( 9191 sqlite3 *db, /* The database connection */ 9192 const char *zSchema, /* Which DB to serialize. ex: "main", "temp", ... */ 9193 sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */ 9194 unsigned int mFlags /* Zero or more SQLITE_SERIALIZE_* flags */ 9195); 9196 9197/* 9198** CAPI3REF: Flags for sqlite3_serialize 9199** 9200** Zero or more of the following constants can be OR-ed together for 9201** the F argument to [sqlite3_serialize(D,S,P,F)]. 9202** 9203** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return 9204** a pointer to contiguous in-memory database that it is currently using, 9205** without making a copy of the database. If SQLite is not currently using 9206** a contiguous in-memory database, then this option causes 9207** [sqlite3_serialize()] to return a NULL pointer. SQLite will only be 9208** using a contiguous in-memory database if it has been initialized by a 9209** prior call to [sqlite3_deserialize()]. 9210*/ 9211#define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */ 9212 9213/* 9214** CAPI3REF: Deserialize a database 9215** 9216** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the 9217** [database connection] D to disconnect from database S and then 9218** reopen S as an in-memory database based on the serialization contained 9219** in P. The serialized database P is N bytes in size. M is the size of 9220** the buffer P, which might be larger than N. If M is larger than N, and 9221** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is 9222** permitted to add content to the in-memory database as long as the total 9223** size does not exceed M bytes. 9224** 9225** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will 9226** invoke sqlite3_free() on the serialization buffer when the database 9227** connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then 9228** SQLite will try to increase the buffer size using sqlite3_realloc64() 9229** if writes on the database cause it to grow larger than M bytes. 9230** 9231** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the 9232** database is currently in a read transaction or is involved in a backup 9233** operation. 9234** 9235** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the 9236** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then 9237** [sqlite3_free()] is invoked on argument P prior to returning. 9238** 9239** This interface is only available if SQLite is compiled with the 9240** [SQLITE_ENABLE_DESERIALIZE] option. 9241*/ 9242int sqlite3_deserialize( 9243 sqlite3 *db, /* The database connection */ 9244 const char *zSchema, /* Which DB to reopen with the deserialization */ 9245 unsigned char *pData, /* The serialized database content */ 9246 sqlite3_int64 szDb, /* Number bytes in the deserialization */ 9247 sqlite3_int64 szBuf, /* Total size of buffer pData[] */ 9248 unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */ 9249); 9250 9251/* 9252** CAPI3REF: Flags for sqlite3_deserialize() 9253** 9254** The following are allowed values for 6th argument (the F argument) to 9255** the [sqlite3_deserialize(D,S,P,N,M,F)] interface. 9256** 9257** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization 9258** in the P argument is held in memory obtained from [sqlite3_malloc64()] 9259** and that SQLite should take ownership of this memory and automatically 9260** free it when it has finished using it. Without this flag, the caller 9261** is responsible for freeing any dynamically allocated memory. 9262** 9263** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to 9264** grow the size of the database using calls to [sqlite3_realloc64()]. This 9265** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used. 9266** Without this flag, the deserialized database cannot increase in size beyond 9267** the number of bytes specified by the M parameter. 9268** 9269** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database 9270** should be treated as read-only. 9271*/ 9272#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */ 9273#define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */ 9274#define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */ 9275 9276/* 9277** Undo the hack that converts floating point types to integer for 9278** builds on processors without floating point support. 9279*/ 9280#ifdef SQLITE_OMIT_FLOATING_POINT 9281# undef double 9282#endif 9283 9284#ifdef __cplusplus 9285} /* End of the 'extern "C"' block */ 9286#endif 9287#endif /* SQLITE3_H */ 9288