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** [[SQLITE_DBCONFIG_LOOKASIDE]] 2021** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 2022** <dd> ^This option takes three additional arguments that determine the 2023** [lookaside memory allocator] configuration for the [database connection]. 2024** ^The first argument (the third parameter to [sqlite3_db_config()] is a 2025** pointer to a memory buffer to use for lookaside memory. 2026** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 2027** may be NULL in which case SQLite will allocate the 2028** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 2029** size of each lookaside buffer slot. ^The third argument is the number of 2030** slots. The size of the buffer in the first argument must be greater than 2031** or equal to the product of the second and third arguments. The buffer 2032** must be aligned to an 8-byte boundary. ^If the second argument to 2033** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 2034** rounded down to the next smaller multiple of 8. ^(The lookaside memory 2035** configuration for a database connection can only be changed when that 2036** connection is not currently using lookaside memory, or in other words 2037** when the "current value" returned by 2038** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 2039** Any attempt to change the lookaside memory configuration when lookaside 2040** memory is in use leaves the configuration unchanged and returns 2041** [SQLITE_BUSY].)^</dd> 2042** 2043** [[SQLITE_DBCONFIG_ENABLE_FKEY]] 2044** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 2045** <dd> ^This option is used to enable or disable the enforcement of 2046** [foreign key constraints]. There should be two additional arguments. 2047** The first argument is an integer which is 0 to disable FK enforcement, 2048** positive to enable FK enforcement or negative to leave FK enforcement 2049** unchanged. The second parameter is a pointer to an integer into which 2050** is written 0 or 1 to indicate whether FK enforcement is off or on 2051** following this call. The second parameter may be a NULL pointer, in 2052** which case the FK enforcement setting is not reported back. </dd> 2053** 2054** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]] 2055** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 2056** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 2057** There should be two additional arguments. 2058** The first argument is an integer which is 0 to disable triggers, 2059** positive to enable triggers or negative to leave the setting unchanged. 2060** The second parameter is a pointer to an integer into which 2061** is written 0 or 1 to indicate whether triggers are disabled or enabled 2062** following this call. The second parameter may be a NULL pointer, in 2063** which case the trigger setting is not reported back. </dd> 2064** 2065** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]] 2066** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 2067** <dd> ^This option is used to enable or disable the two-argument 2068** version of the [fts3_tokenizer()] function which is part of the 2069** [FTS3] full-text search engine extension. 2070** There should be two additional arguments. 2071** The first argument is an integer which is 0 to disable fts3_tokenizer() or 2072** positive to enable fts3_tokenizer() or negative to leave the setting 2073** unchanged. 2074** The second parameter is a pointer to an integer into which 2075** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 2076** following this call. The second parameter may be a NULL pointer, in 2077** which case the new setting is not reported back. </dd> 2078** 2079** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]] 2080** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 2081** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 2082** interface independently of the [load_extension()] SQL function. 2083** The [sqlite3_enable_load_extension()] API enables or disables both the 2084** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 2085** There should be two additional arguments. 2086** When the first argument to this interface is 1, then only the C-API is 2087** enabled and the SQL function remains disabled. If the first argument to 2088** this interface is 0, then both the C-API and the SQL function are disabled. 2089** If the first argument is -1, then no changes are made to state of either the 2090** C-API or the SQL function. 2091** The second parameter is a pointer to an integer into which 2092** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 2093** is disabled or enabled following this call. The second parameter may 2094** be a NULL pointer, in which case the new setting is not reported back. 2095** </dd> 2096** 2097** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 2098** <dd> ^This option is used to change the name of the "main" database 2099** schema. ^The sole argument is a pointer to a constant UTF8 string 2100** which will become the new schema name in place of "main". ^SQLite 2101** does not make a copy of the new main schema name string, so the application 2102** must ensure that the argument passed into this DBCONFIG option is unchanged 2103** until after the database connection closes. 2104** </dd> 2105** 2106** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]] 2107** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 2108** <dd> Usually, when a database in wal mode is closed or detached from a 2109** database handle, SQLite checks if this will mean that there are now no 2110** connections at all to the database. If so, it performs a checkpoint 2111** operation before closing the connection. This option may be used to 2112** override this behaviour. The first parameter passed to this operation 2113** is an integer - positive to disable checkpoints-on-close, or zero (the 2114** default) to enable them, and negative to leave the setting unchanged. 2115** The second parameter is a pointer to an integer 2116** into which is written 0 or 1 to indicate whether checkpoints-on-close 2117** have been disabled - 0 if they are not disabled, 1 if they are. 2118** </dd> 2119** 2120** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2121** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2122** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2123** a single SQL query statement will always use the same algorithm regardless 2124** of values of [bound parameters].)^ The QPSG disables some query optimizations 2125** that look at the values of bound parameters, which can make some queries 2126** slower. But the QPSG has the advantage of more predictable behavior. With 2127** the QPSG active, SQLite will always use the same query plan in the field as 2128** was used during testing in the lab. 2129** The first argument to this setting is an integer which is 0 to disable 2130** the QPSG, positive to enable QPSG, or negative to leave the setting 2131** unchanged. The second parameter is a pointer to an integer into which 2132** is written 0 or 1 to indicate whether the QPSG is disabled or enabled 2133** following this call. 2134** </dd> 2135** 2136** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt> 2137** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not 2138** include output for any operations performed by trigger programs. This 2139** option is used to set or clear (the default) a flag that governs this 2140** behavior. The first parameter passed to this operation is an integer - 2141** positive to enable output for trigger programs, or zero to disable it, 2142** or negative to leave the setting unchanged. 2143** The second parameter is a pointer to an integer into which is written 2144** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if 2145** it is not disabled, 1 if it is. 2146** </dd> 2147** 2148** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt> 2149** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run 2150** [VACUUM] in order to reset a database back to an empty database 2151** with no schema and no content. The following process works even for 2152** a badly corrupted database file: 2153** <ol> 2154** <li> If the database connection is newly opened, make sure it has read the 2155** database schema by preparing then discarding some query against the 2156** database, or calling sqlite3_table_column_metadata(), ignoring any 2157** errors. This step is only necessary if the application desires to keep 2158** the database in WAL mode after the reset if it was in WAL mode before 2159** the reset. 2160** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0); 2161** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0); 2162** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0); 2163** </ol> 2164** Because resetting a database is destructive and irreversible, the 2165** process requires the use of this obscure API and multiple steps to help 2166** ensure that it does not happen by accident. 2167** 2168** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt> 2169** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the 2170** "defensive" flag for a database connection. When the defensive 2171** flag is enabled, language features that allow ordinary SQL to 2172** deliberately corrupt the database file are disabled. The disabled 2173** features include but are not limited to the following: 2174** <ul> 2175** <li> The [PRAGMA writable_schema=ON] statement. 2176** <li> Writes to the [sqlite_dbpage] virtual table. 2177** <li> Direct writes to [shadow tables]. 2178** </ul> 2179** </dd> 2180** </dl> 2181*/ 2182#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2183#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2184#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2185#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2186#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2187#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2188#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2189#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2190#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */ 2191#define SQLITE_DBCONFIG_RESET_DATABASE 1009 /* int int* */ 2192#define SQLITE_DBCONFIG_DEFENSIVE 1010 /* int int* */ 2193#define SQLITE_DBCONFIG_MAX 1010 /* Largest DBCONFIG */ 2194 2195/* 2196** CAPI3REF: Enable Or Disable Extended Result Codes 2197** METHOD: sqlite3 2198** 2199** ^The sqlite3_extended_result_codes() routine enables or disables the 2200** [extended result codes] feature of SQLite. ^The extended result 2201** codes are disabled by default for historical compatibility. 2202*/ 2203int sqlite3_extended_result_codes(sqlite3*, int onoff); 2204 2205/* 2206** CAPI3REF: Last Insert Rowid 2207** METHOD: sqlite3 2208** 2209** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2210** has a unique 64-bit signed 2211** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2212** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2213** names are not also used by explicitly declared columns. ^If 2214** the table has a column of type [INTEGER PRIMARY KEY] then that column 2215** is another alias for the rowid. 2216** 2217** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2218** the most recent successful [INSERT] into a rowid table or [virtual table] 2219** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2220** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2221** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2222** zero. 2223** 2224** As well as being set automatically as rows are inserted into database 2225** tables, the value returned by this function may be set explicitly by 2226** [sqlite3_set_last_insert_rowid()] 2227** 2228** Some virtual table implementations may INSERT rows into rowid tables as 2229** part of committing a transaction (e.g. to flush data accumulated in memory 2230** to disk). In this case subsequent calls to this function return the rowid 2231** associated with these internal INSERT operations, which leads to 2232** unintuitive results. Virtual table implementations that do write to rowid 2233** tables in this way can avoid this problem by restoring the original 2234** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2235** control to the user. 2236** 2237** ^(If an [INSERT] occurs within a trigger then this routine will 2238** return the [rowid] of the inserted row as long as the trigger is 2239** running. Once the trigger program ends, the value returned 2240** by this routine reverts to what it was before the trigger was fired.)^ 2241** 2242** ^An [INSERT] that fails due to a constraint violation is not a 2243** successful [INSERT] and does not change the value returned by this 2244** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2245** and INSERT OR ABORT make no changes to the return value of this 2246** routine when their insertion fails. ^(When INSERT OR REPLACE 2247** encounters a constraint violation, it does not fail. The 2248** INSERT continues to completion after deleting rows that caused 2249** the constraint problem so INSERT OR REPLACE will always change 2250** the return value of this interface.)^ 2251** 2252** ^For the purposes of this routine, an [INSERT] is considered to 2253** be successful even if it is subsequently rolled back. 2254** 2255** This function is accessible to SQL statements via the 2256** [last_insert_rowid() SQL function]. 2257** 2258** If a separate thread performs a new [INSERT] on the same 2259** database connection while the [sqlite3_last_insert_rowid()] 2260** function is running and thus changes the last insert [rowid], 2261** then the value returned by [sqlite3_last_insert_rowid()] is 2262** unpredictable and might not equal either the old or the new 2263** last insert [rowid]. 2264*/ 2265sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2266 2267/* 2268** CAPI3REF: Set the Last Insert Rowid value. 2269** METHOD: sqlite3 2270** 2271** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2272** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2273** without inserting a row into the database. 2274*/ 2275void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2276 2277/* 2278** CAPI3REF: Count The Number Of Rows Modified 2279** METHOD: sqlite3 2280** 2281** ^This function returns the number of rows modified, inserted or 2282** deleted by the most recently completed INSERT, UPDATE or DELETE 2283** statement on the database connection specified by the only parameter. 2284** ^Executing any other type of SQL statement does not modify the value 2285** returned by this function. 2286** 2287** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2288** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2289** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2290** 2291** Changes to a view that are intercepted by 2292** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2293** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2294** DELETE statement run on a view is always zero. Only changes made to real 2295** tables are counted. 2296** 2297** Things are more complicated if the sqlite3_changes() function is 2298** executed while a trigger program is running. This may happen if the 2299** program uses the [changes() SQL function], or if some other callback 2300** function invokes sqlite3_changes() directly. Essentially: 2301** 2302** <ul> 2303** <li> ^(Before entering a trigger program the value returned by 2304** sqlite3_changes() function is saved. After the trigger program 2305** has finished, the original value is restored.)^ 2306** 2307** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2308** statement sets the value returned by sqlite3_changes() 2309** upon completion as normal. Of course, this value will not include 2310** any changes performed by sub-triggers, as the sqlite3_changes() 2311** value will be saved and restored after each sub-trigger has run.)^ 2312** </ul> 2313** 2314** ^This means that if the changes() SQL function (or similar) is used 2315** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2316** returns the value as set when the calling statement began executing. 2317** ^If it is used by the second or subsequent such statement within a trigger 2318** program, the value returned reflects the number of rows modified by the 2319** previous INSERT, UPDATE or DELETE statement within the same trigger. 2320** 2321** If a separate thread makes changes on the same database connection 2322** while [sqlite3_changes()] is running then the value returned 2323** is unpredictable and not meaningful. 2324** 2325** See also: 2326** <ul> 2327** <li> the [sqlite3_total_changes()] interface 2328** <li> the [count_changes pragma] 2329** <li> the [changes() SQL function] 2330** <li> the [data_version pragma] 2331** </ul> 2332*/ 2333int sqlite3_changes(sqlite3*); 2334 2335/* 2336** CAPI3REF: Total Number Of Rows Modified 2337** METHOD: sqlite3 2338** 2339** ^This function returns the total number of rows inserted, modified or 2340** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2341** since the database connection was opened, including those executed as 2342** part of trigger programs. ^Executing any other type of SQL statement 2343** does not affect the value returned by sqlite3_total_changes(). 2344** 2345** ^Changes made as part of [foreign key actions] are included in the 2346** count, but those made as part of REPLACE constraint resolution are 2347** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2348** are not counted. 2349** 2350** This the [sqlite3_total_changes(D)] interface only reports the number 2351** of rows that changed due to SQL statement run against database 2352** connection D. Any changes by other database connections are ignored. 2353** To detect changes against a database file from other database 2354** connections use the [PRAGMA data_version] command or the 2355** [SQLITE_FCNTL_DATA_VERSION] [file control]. 2356** 2357** If a separate thread makes changes on the same database connection 2358** while [sqlite3_total_changes()] is running then the value 2359** returned is unpredictable and not meaningful. 2360** 2361** See also: 2362** <ul> 2363** <li> the [sqlite3_changes()] interface 2364** <li> the [count_changes pragma] 2365** <li> the [changes() SQL function] 2366** <li> the [data_version pragma] 2367** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control] 2368** </ul> 2369*/ 2370int sqlite3_total_changes(sqlite3*); 2371 2372/* 2373** CAPI3REF: Interrupt A Long-Running Query 2374** METHOD: sqlite3 2375** 2376** ^This function causes any pending database operation to abort and 2377** return at its earliest opportunity. This routine is typically 2378** called in response to a user action such as pressing "Cancel" 2379** or Ctrl-C where the user wants a long query operation to halt 2380** immediately. 2381** 2382** ^It is safe to call this routine from a thread different from the 2383** thread that is currently running the database operation. But it 2384** is not safe to call this routine with a [database connection] that 2385** is closed or might close before sqlite3_interrupt() returns. 2386** 2387** ^If an SQL operation is very nearly finished at the time when 2388** sqlite3_interrupt() is called, then it might not have an opportunity 2389** to be interrupted and might continue to completion. 2390** 2391** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2392** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2393** that is inside an explicit transaction, then the entire transaction 2394** will be rolled back automatically. 2395** 2396** ^The sqlite3_interrupt(D) call is in effect until all currently running 2397** SQL statements on [database connection] D complete. ^Any new SQL statements 2398** that are started after the sqlite3_interrupt() call and before the 2399** running statements reaches zero are interrupted as if they had been 2400** running prior to the sqlite3_interrupt() call. ^New SQL statements 2401** that are started after the running statement count reaches zero are 2402** not effected by the sqlite3_interrupt(). 2403** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2404** SQL statements is a no-op and has no effect on SQL statements 2405** that are started after the sqlite3_interrupt() call returns. 2406*/ 2407void sqlite3_interrupt(sqlite3*); 2408 2409/* 2410** CAPI3REF: Determine If An SQL Statement Is Complete 2411** 2412** These routines are useful during command-line input to determine if the 2413** currently entered text seems to form a complete SQL statement or 2414** if additional input is needed before sending the text into 2415** SQLite for parsing. ^These routines return 1 if the input string 2416** appears to be a complete SQL statement. ^A statement is judged to be 2417** complete if it ends with a semicolon token and is not a prefix of a 2418** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2419** string literals or quoted identifier names or comments are not 2420** independent tokens (they are part of the token in which they are 2421** embedded) and thus do not count as a statement terminator. ^Whitespace 2422** and comments that follow the final semicolon are ignored. 2423** 2424** ^These routines return 0 if the statement is incomplete. ^If a 2425** memory allocation fails, then SQLITE_NOMEM is returned. 2426** 2427** ^These routines do not parse the SQL statements thus 2428** will not detect syntactically incorrect SQL. 2429** 2430** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2431** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2432** automatically by sqlite3_complete16(). If that initialization fails, 2433** then the return value from sqlite3_complete16() will be non-zero 2434** regardless of whether or not the input SQL is complete.)^ 2435** 2436** The input to [sqlite3_complete()] must be a zero-terminated 2437** UTF-8 string. 2438** 2439** The input to [sqlite3_complete16()] must be a zero-terminated 2440** UTF-16 string in native byte order. 2441*/ 2442int sqlite3_complete(const char *sql); 2443int sqlite3_complete16(const void *sql); 2444 2445/* 2446** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2447** KEYWORDS: {busy-handler callback} {busy handler} 2448** METHOD: sqlite3 2449** 2450** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2451** that might be invoked with argument P whenever 2452** an attempt is made to access a database table associated with 2453** [database connection] D when another thread 2454** or process has the table locked. 2455** The sqlite3_busy_handler() interface is used to implement 2456** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2457** 2458** ^If the busy callback is NULL, then [SQLITE_BUSY] 2459** is returned immediately upon encountering the lock. ^If the busy callback 2460** is not NULL, then the callback might be invoked with two arguments. 2461** 2462** ^The first argument to the busy handler is a copy of the void* pointer which 2463** is the third argument to sqlite3_busy_handler(). ^The second argument to 2464** the busy handler callback is the number of times that the busy handler has 2465** been invoked previously for the same locking event. ^If the 2466** busy callback returns 0, then no additional attempts are made to 2467** access the database and [SQLITE_BUSY] is returned 2468** to the application. 2469** ^If the callback returns non-zero, then another attempt 2470** is made to access the database and the cycle repeats. 2471** 2472** The presence of a busy handler does not guarantee that it will be invoked 2473** when there is lock contention. ^If SQLite determines that invoking the busy 2474** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2475** to the application instead of invoking the 2476** busy handler. 2477** Consider a scenario where one process is holding a read lock that 2478** it is trying to promote to a reserved lock and 2479** a second process is holding a reserved lock that it is trying 2480** to promote to an exclusive lock. The first process cannot proceed 2481** because it is blocked by the second and the second process cannot 2482** proceed because it is blocked by the first. If both processes 2483** invoke the busy handlers, neither will make any progress. Therefore, 2484** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2485** will induce the first process to release its read lock and allow 2486** the second process to proceed. 2487** 2488** ^The default busy callback is NULL. 2489** 2490** ^(There can only be a single busy handler defined for each 2491** [database connection]. Setting a new busy handler clears any 2492** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2493** or evaluating [PRAGMA busy_timeout=N] will change the 2494** busy handler and thus clear any previously set busy handler. 2495** 2496** The busy callback should not take any actions which modify the 2497** database connection that invoked the busy handler. In other words, 2498** the busy handler is not reentrant. Any such actions 2499** result in undefined behavior. 2500** 2501** A busy handler must not close the database connection 2502** or [prepared statement] that invoked the busy handler. 2503*/ 2504int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2505 2506/* 2507** CAPI3REF: Set A Busy Timeout 2508** METHOD: sqlite3 2509** 2510** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2511** for a specified amount of time when a table is locked. ^The handler 2512** will sleep multiple times until at least "ms" milliseconds of sleeping 2513** have accumulated. ^After at least "ms" milliseconds of sleeping, 2514** the handler returns 0 which causes [sqlite3_step()] to return 2515** [SQLITE_BUSY]. 2516** 2517** ^Calling this routine with an argument less than or equal to zero 2518** turns off all busy handlers. 2519** 2520** ^(There can only be a single busy handler for a particular 2521** [database connection] at any given moment. If another busy handler 2522** was defined (using [sqlite3_busy_handler()]) prior to calling 2523** this routine, that other busy handler is cleared.)^ 2524** 2525** See also: [PRAGMA busy_timeout] 2526*/ 2527int sqlite3_busy_timeout(sqlite3*, int ms); 2528 2529/* 2530** CAPI3REF: Convenience Routines For Running Queries 2531** METHOD: sqlite3 2532** 2533** This is a legacy interface that is preserved for backwards compatibility. 2534** Use of this interface is not recommended. 2535** 2536** Definition: A <b>result table</b> is memory data structure created by the 2537** [sqlite3_get_table()] interface. A result table records the 2538** complete query results from one or more queries. 2539** 2540** The table conceptually has a number of rows and columns. But 2541** these numbers are not part of the result table itself. These 2542** numbers are obtained separately. Let N be the number of rows 2543** and M be the number of columns. 2544** 2545** A result table is an array of pointers to zero-terminated UTF-8 strings. 2546** There are (N+1)*M elements in the array. The first M pointers point 2547** to zero-terminated strings that contain the names of the columns. 2548** The remaining entries all point to query results. NULL values result 2549** in NULL pointers. All other values are in their UTF-8 zero-terminated 2550** string representation as returned by [sqlite3_column_text()]. 2551** 2552** A result table might consist of one or more memory allocations. 2553** It is not safe to pass a result table directly to [sqlite3_free()]. 2554** A result table should be deallocated using [sqlite3_free_table()]. 2555** 2556** ^(As an example of the result table format, suppose a query result 2557** is as follows: 2558** 2559** <blockquote><pre> 2560** Name | Age 2561** ----------------------- 2562** Alice | 43 2563** Bob | 28 2564** Cindy | 21 2565** </pre></blockquote> 2566** 2567** There are two column (M==2) and three rows (N==3). Thus the 2568** result table has 8 entries. Suppose the result table is stored 2569** in an array names azResult. Then azResult holds this content: 2570** 2571** <blockquote><pre> 2572** azResult[0] = "Name"; 2573** azResult[1] = "Age"; 2574** azResult[2] = "Alice"; 2575** azResult[3] = "43"; 2576** azResult[4] = "Bob"; 2577** azResult[5] = "28"; 2578** azResult[6] = "Cindy"; 2579** azResult[7] = "21"; 2580** </pre></blockquote>)^ 2581** 2582** ^The sqlite3_get_table() function evaluates one or more 2583** semicolon-separated SQL statements in the zero-terminated UTF-8 2584** string of its 2nd parameter and returns a result table to the 2585** pointer given in its 3rd parameter. 2586** 2587** After the application has finished with the result from sqlite3_get_table(), 2588** it must pass the result table pointer to sqlite3_free_table() in order to 2589** release the memory that was malloced. Because of the way the 2590** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2591** function must not try to call [sqlite3_free()] directly. Only 2592** [sqlite3_free_table()] is able to release the memory properly and safely. 2593** 2594** The sqlite3_get_table() interface is implemented as a wrapper around 2595** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2596** to any internal data structures of SQLite. It uses only the public 2597** interface defined here. As a consequence, errors that occur in the 2598** wrapper layer outside of the internal [sqlite3_exec()] call are not 2599** reflected in subsequent calls to [sqlite3_errcode()] or 2600** [sqlite3_errmsg()]. 2601*/ 2602int sqlite3_get_table( 2603 sqlite3 *db, /* An open database */ 2604 const char *zSql, /* SQL to be evaluated */ 2605 char ***pazResult, /* Results of the query */ 2606 int *pnRow, /* Number of result rows written here */ 2607 int *pnColumn, /* Number of result columns written here */ 2608 char **pzErrmsg /* Error msg written here */ 2609); 2610void sqlite3_free_table(char **result); 2611 2612/* 2613** CAPI3REF: Formatted String Printing Functions 2614** 2615** These routines are work-alikes of the "printf()" family of functions 2616** from the standard C library. 2617** These routines understand most of the common formatting options from 2618** the standard library printf() 2619** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]). 2620** See the [built-in printf()] documentation for details. 2621** 2622** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2623** results into memory obtained from [sqlite3_malloc64()]. 2624** The strings returned by these two routines should be 2625** released by [sqlite3_free()]. ^Both routines return a 2626** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough 2627** memory to hold the resulting string. 2628** 2629** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2630** the standard C library. The result is written into the 2631** buffer supplied as the second parameter whose size is given by 2632** the first parameter. Note that the order of the 2633** first two parameters is reversed from snprintf().)^ This is an 2634** historical accident that cannot be fixed without breaking 2635** backwards compatibility. ^(Note also that sqlite3_snprintf() 2636** returns a pointer to its buffer instead of the number of 2637** characters actually written into the buffer.)^ We admit that 2638** the number of characters written would be a more useful return 2639** value but we cannot change the implementation of sqlite3_snprintf() 2640** now without breaking compatibility. 2641** 2642** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2643** guarantees that the buffer is always zero-terminated. ^The first 2644** parameter "n" is the total size of the buffer, including space for 2645** the zero terminator. So the longest string that can be completely 2646** written will be n-1 characters. 2647** 2648** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2649** 2650** See also: [built-in printf()], [printf() SQL function] 2651*/ 2652char *sqlite3_mprintf(const char*,...); 2653char *sqlite3_vmprintf(const char*, va_list); 2654char *sqlite3_snprintf(int,char*,const char*, ...); 2655char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2656 2657/* 2658** CAPI3REF: Memory Allocation Subsystem 2659** 2660** The SQLite core uses these three routines for all of its own 2661** internal memory allocation needs. "Core" in the previous sentence 2662** does not include operating-system specific VFS implementation. The 2663** Windows VFS uses native malloc() and free() for some operations. 2664** 2665** ^The sqlite3_malloc() routine returns a pointer to a block 2666** of memory at least N bytes in length, where N is the parameter. 2667** ^If sqlite3_malloc() is unable to obtain sufficient free 2668** memory, it returns a NULL pointer. ^If the parameter N to 2669** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2670** a NULL pointer. 2671** 2672** ^The sqlite3_malloc64(N) routine works just like 2673** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2674** of a signed 32-bit integer. 2675** 2676** ^Calling sqlite3_free() with a pointer previously returned 2677** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2678** that it might be reused. ^The sqlite3_free() routine is 2679** a no-op if is called with a NULL pointer. Passing a NULL pointer 2680** to sqlite3_free() is harmless. After being freed, memory 2681** should neither be read nor written. Even reading previously freed 2682** memory might result in a segmentation fault or other severe error. 2683** Memory corruption, a segmentation fault, or other severe error 2684** might result if sqlite3_free() is called with a non-NULL pointer that 2685** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2686** 2687** ^The sqlite3_realloc(X,N) interface attempts to resize a 2688** prior memory allocation X to be at least N bytes. 2689** ^If the X parameter to sqlite3_realloc(X,N) 2690** is a NULL pointer then its behavior is identical to calling 2691** sqlite3_malloc(N). 2692** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2693** negative then the behavior is exactly the same as calling 2694** sqlite3_free(X). 2695** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2696** of at least N bytes in size or NULL if insufficient memory is available. 2697** ^If M is the size of the prior allocation, then min(N,M) bytes 2698** of the prior allocation are copied into the beginning of buffer returned 2699** by sqlite3_realloc(X,N) and the prior allocation is freed. 2700** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2701** prior allocation is not freed. 2702** 2703** ^The sqlite3_realloc64(X,N) interfaces works the same as 2704** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2705** of a 32-bit signed integer. 2706** 2707** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2708** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2709** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2710** ^The value returned by sqlite3_msize(X) might be larger than the number 2711** of bytes requested when X was allocated. ^If X is a NULL pointer then 2712** sqlite3_msize(X) returns zero. If X points to something that is not 2713** the beginning of memory allocation, or if it points to a formerly 2714** valid memory allocation that has now been freed, then the behavior 2715** of sqlite3_msize(X) is undefined and possibly harmful. 2716** 2717** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2718** sqlite3_malloc64(), and sqlite3_realloc64() 2719** is always aligned to at least an 8 byte boundary, or to a 2720** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2721** option is used. 2722** 2723** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2724** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2725** implementation of these routines to be omitted. That capability 2726** is no longer provided. Only built-in memory allocators can be used. 2727** 2728** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2729** the system malloc() and free() directly when converting 2730** filenames between the UTF-8 encoding used by SQLite 2731** and whatever filename encoding is used by the particular Windows 2732** installation. Memory allocation errors were detected, but 2733** they were reported back as [SQLITE_CANTOPEN] or 2734** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2735** 2736** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2737** must be either NULL or else pointers obtained from a prior 2738** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2739** not yet been released. 2740** 2741** The application must not read or write any part of 2742** a block of memory after it has been released using 2743** [sqlite3_free()] or [sqlite3_realloc()]. 2744*/ 2745void *sqlite3_malloc(int); 2746void *sqlite3_malloc64(sqlite3_uint64); 2747void *sqlite3_realloc(void*, int); 2748void *sqlite3_realloc64(void*, sqlite3_uint64); 2749void sqlite3_free(void*); 2750sqlite3_uint64 sqlite3_msize(void*); 2751 2752/* 2753** CAPI3REF: Memory Allocator Statistics 2754** 2755** SQLite provides these two interfaces for reporting on the status 2756** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2757** routines, which form the built-in memory allocation subsystem. 2758** 2759** ^The [sqlite3_memory_used()] routine returns the number of bytes 2760** of memory currently outstanding (malloced but not freed). 2761** ^The [sqlite3_memory_highwater()] routine returns the maximum 2762** value of [sqlite3_memory_used()] since the high-water mark 2763** was last reset. ^The values returned by [sqlite3_memory_used()] and 2764** [sqlite3_memory_highwater()] include any overhead 2765** added by SQLite in its implementation of [sqlite3_malloc()], 2766** but not overhead added by the any underlying system library 2767** routines that [sqlite3_malloc()] may call. 2768** 2769** ^The memory high-water mark is reset to the current value of 2770** [sqlite3_memory_used()] if and only if the parameter to 2771** [sqlite3_memory_highwater()] is true. ^The value returned 2772** by [sqlite3_memory_highwater(1)] is the high-water mark 2773** prior to the reset. 2774*/ 2775sqlite3_int64 sqlite3_memory_used(void); 2776sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2777 2778/* 2779** CAPI3REF: Pseudo-Random Number Generator 2780** 2781** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2782** select random [ROWID | ROWIDs] when inserting new records into a table that 2783** already uses the largest possible [ROWID]. The PRNG is also used for 2784** the build-in random() and randomblob() SQL functions. This interface allows 2785** applications to access the same PRNG for other purposes. 2786** 2787** ^A call to this routine stores N bytes of randomness into buffer P. 2788** ^The P parameter can be a NULL pointer. 2789** 2790** ^If this routine has not been previously called or if the previous 2791** call had N less than one or a NULL pointer for P, then the PRNG is 2792** seeded using randomness obtained from the xRandomness method of 2793** the default [sqlite3_vfs] object. 2794** ^If the previous call to this routine had an N of 1 or more and a 2795** non-NULL P then the pseudo-randomness is generated 2796** internally and without recourse to the [sqlite3_vfs] xRandomness 2797** method. 2798*/ 2799void sqlite3_randomness(int N, void *P); 2800 2801/* 2802** CAPI3REF: Compile-Time Authorization Callbacks 2803** METHOD: sqlite3 2804** KEYWORDS: {authorizer callback} 2805** 2806** ^This routine registers an authorizer callback with a particular 2807** [database connection], supplied in the first argument. 2808** ^The authorizer callback is invoked as SQL statements are being compiled 2809** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2810** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2811** and [sqlite3_prepare16_v3()]. ^At various 2812** points during the compilation process, as logic is being created 2813** to perform various actions, the authorizer callback is invoked to 2814** see if those actions are allowed. ^The authorizer callback should 2815** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2816** specific action but allow the SQL statement to continue to be 2817** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2818** rejected with an error. ^If the authorizer callback returns 2819** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2820** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2821** the authorizer will fail with an error message. 2822** 2823** When the callback returns [SQLITE_OK], that means the operation 2824** requested is ok. ^When the callback returns [SQLITE_DENY], the 2825** [sqlite3_prepare_v2()] or equivalent call that triggered the 2826** authorizer will fail with an error message explaining that 2827** access is denied. 2828** 2829** ^The first parameter to the authorizer callback is a copy of the third 2830** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2831** to the callback is an integer [SQLITE_COPY | action code] that specifies 2832** the particular action to be authorized. ^The third through sixth parameters 2833** to the callback are either NULL pointers or zero-terminated strings 2834** that contain additional details about the action to be authorized. 2835** Applications must always be prepared to encounter a NULL pointer in any 2836** of the third through the sixth parameters of the authorization callback. 2837** 2838** ^If the action code is [SQLITE_READ] 2839** and the callback returns [SQLITE_IGNORE] then the 2840** [prepared statement] statement is constructed to substitute 2841** a NULL value in place of the table column that would have 2842** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2843** return can be used to deny an untrusted user access to individual 2844** columns of a table. 2845** ^When a table is referenced by a [SELECT] but no column values are 2846** extracted from that table (for example in a query like 2847** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2848** is invoked once for that table with a column name that is an empty string. 2849** ^If the action code is [SQLITE_DELETE] and the callback returns 2850** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2851** [truncate optimization] is disabled and all rows are deleted individually. 2852** 2853** An authorizer is used when [sqlite3_prepare | preparing] 2854** SQL statements from an untrusted source, to ensure that the SQL statements 2855** do not try to access data they are not allowed to see, or that they do not 2856** try to execute malicious statements that damage the database. For 2857** example, an application may allow a user to enter arbitrary 2858** SQL queries for evaluation by a database. But the application does 2859** not want the user to be able to make arbitrary changes to the 2860** database. An authorizer could then be put in place while the 2861** user-entered SQL is being [sqlite3_prepare | prepared] that 2862** disallows everything except [SELECT] statements. 2863** 2864** Applications that need to process SQL from untrusted sources 2865** might also consider lowering resource limits using [sqlite3_limit()] 2866** and limiting database size using the [max_page_count] [PRAGMA] 2867** in addition to using an authorizer. 2868** 2869** ^(Only a single authorizer can be in place on a database connection 2870** at a time. Each call to sqlite3_set_authorizer overrides the 2871** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2872** The authorizer is disabled by default. 2873** 2874** The authorizer callback must not do anything that will modify 2875** the database connection that invoked the authorizer callback. 2876** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2877** database connections for the meaning of "modify" in this paragraph. 2878** 2879** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2880** statement might be re-prepared during [sqlite3_step()] due to a 2881** schema change. Hence, the application should ensure that the 2882** correct authorizer callback remains in place during the [sqlite3_step()]. 2883** 2884** ^Note that the authorizer callback is invoked only during 2885** [sqlite3_prepare()] or its variants. Authorization is not 2886** performed during statement evaluation in [sqlite3_step()], unless 2887** as stated in the previous paragraph, sqlite3_step() invokes 2888** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2889*/ 2890int sqlite3_set_authorizer( 2891 sqlite3*, 2892 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2893 void *pUserData 2894); 2895 2896/* 2897** CAPI3REF: Authorizer Return Codes 2898** 2899** The [sqlite3_set_authorizer | authorizer callback function] must 2900** return either [SQLITE_OK] or one of these two constants in order 2901** to signal SQLite whether or not the action is permitted. See the 2902** [sqlite3_set_authorizer | authorizer documentation] for additional 2903** information. 2904** 2905** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2906** returned from the [sqlite3_vtab_on_conflict()] interface. 2907*/ 2908#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2909#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2910 2911/* 2912** CAPI3REF: Authorizer Action Codes 2913** 2914** The [sqlite3_set_authorizer()] interface registers a callback function 2915** that is invoked to authorize certain SQL statement actions. The 2916** second parameter to the callback is an integer code that specifies 2917** what action is being authorized. These are the integer action codes that 2918** the authorizer callback may be passed. 2919** 2920** These action code values signify what kind of operation is to be 2921** authorized. The 3rd and 4th parameters to the authorization 2922** callback function will be parameters or NULL depending on which of these 2923** codes is used as the second parameter. ^(The 5th parameter to the 2924** authorizer callback is the name of the database ("main", "temp", 2925** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2926** is the name of the inner-most trigger or view that is responsible for 2927** the access attempt or NULL if this access attempt is directly from 2928** top-level SQL code. 2929*/ 2930/******************************************* 3rd ************ 4th ***********/ 2931#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2932#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2933#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2934#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2935#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2936#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2937#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2938#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2939#define SQLITE_DELETE 9 /* Table Name NULL */ 2940#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2941#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2942#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2943#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2944#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2945#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2946#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2947#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2948#define SQLITE_INSERT 18 /* Table Name NULL */ 2949#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2950#define SQLITE_READ 20 /* Table Name Column Name */ 2951#define SQLITE_SELECT 21 /* NULL NULL */ 2952#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2953#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2954#define SQLITE_ATTACH 24 /* Filename NULL */ 2955#define SQLITE_DETACH 25 /* Database Name NULL */ 2956#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2957#define SQLITE_REINDEX 27 /* Index Name NULL */ 2958#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2959#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2960#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2961#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2962#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2963#define SQLITE_COPY 0 /* No longer used */ 2964#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2965 2966/* 2967** CAPI3REF: Tracing And Profiling Functions 2968** METHOD: sqlite3 2969** 2970** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 2971** instead of the routines described here. 2972** 2973** These routines register callback functions that can be used for 2974** tracing and profiling the execution of SQL statements. 2975** 2976** ^The callback function registered by sqlite3_trace() is invoked at 2977** various times when an SQL statement is being run by [sqlite3_step()]. 2978** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2979** SQL statement text as the statement first begins executing. 2980** ^(Additional sqlite3_trace() callbacks might occur 2981** as each triggered subprogram is entered. The callbacks for triggers 2982** contain a UTF-8 SQL comment that identifies the trigger.)^ 2983** 2984** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2985** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2986** 2987** ^The callback function registered by sqlite3_profile() is invoked 2988** as each SQL statement finishes. ^The profile callback contains 2989** the original statement text and an estimate of wall-clock time 2990** of how long that statement took to run. ^The profile callback 2991** time is in units of nanoseconds, however the current implementation 2992** is only capable of millisecond resolution so the six least significant 2993** digits in the time are meaningless. Future versions of SQLite 2994** might provide greater resolution on the profiler callback. Invoking 2995** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the 2996** profile callback. 2997*/ 2998SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 2999 void(*xTrace)(void*,const char*), void*); 3000SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 3001 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 3002 3003/* 3004** CAPI3REF: SQL Trace Event Codes 3005** KEYWORDS: SQLITE_TRACE 3006** 3007** These constants identify classes of events that can be monitored 3008** using the [sqlite3_trace_v2()] tracing logic. The M argument 3009** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of 3010** the following constants. ^The first argument to the trace callback 3011** is one of the following constants. 3012** 3013** New tracing constants may be added in future releases. 3014** 3015** ^A trace callback has four arguments: xCallback(T,C,P,X). 3016** ^The T argument is one of the integer type codes above. 3017** ^The C argument is a copy of the context pointer passed in as the 3018** fourth argument to [sqlite3_trace_v2()]. 3019** The P and X arguments are pointers whose meanings depend on T. 3020** 3021** <dl> 3022** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 3023** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 3024** first begins running and possibly at other times during the 3025** execution of the prepared statement, such as at the start of each 3026** trigger subprogram. ^The P argument is a pointer to the 3027** [prepared statement]. ^The X argument is a pointer to a string which 3028** is the unexpanded SQL text of the prepared statement or an SQL comment 3029** that indicates the invocation of a trigger. ^The callback can compute 3030** the same text that would have been returned by the legacy [sqlite3_trace()] 3031** interface by using the X argument when X begins with "--" and invoking 3032** [sqlite3_expanded_sql(P)] otherwise. 3033** 3034** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 3035** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 3036** information as is provided by the [sqlite3_profile()] callback. 3037** ^The P argument is a pointer to the [prepared statement] and the 3038** X argument points to a 64-bit integer which is the estimated of 3039** the number of nanosecond that the prepared statement took to run. 3040** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 3041** 3042** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 3043** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 3044** statement generates a single row of result. 3045** ^The P argument is a pointer to the [prepared statement] and the 3046** X argument is unused. 3047** 3048** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 3049** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 3050** connection closes. 3051** ^The P argument is a pointer to the [database connection] object 3052** and the X argument is unused. 3053** </dl> 3054*/ 3055#define SQLITE_TRACE_STMT 0x01 3056#define SQLITE_TRACE_PROFILE 0x02 3057#define SQLITE_TRACE_ROW 0x04 3058#define SQLITE_TRACE_CLOSE 0x08 3059 3060/* 3061** CAPI3REF: SQL Trace Hook 3062** METHOD: sqlite3 3063** 3064** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 3065** function X against [database connection] D, using property mask M 3066** and context pointer P. ^If the X callback is 3067** NULL or if the M mask is zero, then tracing is disabled. The 3068** M argument should be the bitwise OR-ed combination of 3069** zero or more [SQLITE_TRACE] constants. 3070** 3071** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 3072** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 3073** 3074** ^The X callback is invoked whenever any of the events identified by 3075** mask M occur. ^The integer return value from the callback is currently 3076** ignored, though this may change in future releases. Callback 3077** implementations should return zero to ensure future compatibility. 3078** 3079** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 3080** ^The T argument is one of the [SQLITE_TRACE] 3081** constants to indicate why the callback was invoked. 3082** ^The C argument is a copy of the context pointer. 3083** The P and X arguments are pointers whose meanings depend on T. 3084** 3085** The sqlite3_trace_v2() interface is intended to replace the legacy 3086** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 3087** are deprecated. 3088*/ 3089int sqlite3_trace_v2( 3090 sqlite3*, 3091 unsigned uMask, 3092 int(*xCallback)(unsigned,void*,void*,void*), 3093 void *pCtx 3094); 3095 3096/* 3097** CAPI3REF: Query Progress Callbacks 3098** METHOD: sqlite3 3099** 3100** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 3101** function X to be invoked periodically during long running calls to 3102** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 3103** database connection D. An example use for this 3104** interface is to keep a GUI updated during a large query. 3105** 3106** ^The parameter P is passed through as the only parameter to the 3107** callback function X. ^The parameter N is the approximate number of 3108** [virtual machine instructions] that are evaluated between successive 3109** invocations of the callback X. ^If N is less than one then the progress 3110** handler is disabled. 3111** 3112** ^Only a single progress handler may be defined at one time per 3113** [database connection]; setting a new progress handler cancels the 3114** old one. ^Setting parameter X to NULL disables the progress handler. 3115** ^The progress handler is also disabled by setting N to a value less 3116** than 1. 3117** 3118** ^If the progress callback returns non-zero, the operation is 3119** interrupted. This feature can be used to implement a 3120** "Cancel" button on a GUI progress dialog box. 3121** 3122** The progress handler callback must not do anything that will modify 3123** the database connection that invoked the progress handler. 3124** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3125** database connections for the meaning of "modify" in this paragraph. 3126** 3127*/ 3128void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3129 3130/* 3131** CAPI3REF: Opening A New Database Connection 3132** CONSTRUCTOR: sqlite3 3133** 3134** ^These routines open an SQLite database file as specified by the 3135** filename argument. ^The filename argument is interpreted as UTF-8 for 3136** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3137** order for sqlite3_open16(). ^(A [database connection] handle is usually 3138** returned in *ppDb, even if an error occurs. The only exception is that 3139** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3140** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3141** object.)^ ^(If the database is opened (and/or created) successfully, then 3142** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3143** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3144** an English language description of the error following a failure of any 3145** of the sqlite3_open() routines. 3146** 3147** ^The default encoding will be UTF-8 for databases created using 3148** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3149** created using sqlite3_open16() will be UTF-16 in the native byte order. 3150** 3151** Whether or not an error occurs when it is opened, resources 3152** associated with the [database connection] handle should be released by 3153** passing it to [sqlite3_close()] when it is no longer required. 3154** 3155** The sqlite3_open_v2() interface works like sqlite3_open() 3156** except that it accepts two additional parameters for additional control 3157** over the new database connection. ^(The flags parameter to 3158** sqlite3_open_v2() can take one of 3159** the following three values, optionally combined with the 3160** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 3161** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 3162** 3163** <dl> 3164** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3165** <dd>The database is opened in read-only mode. If the database does not 3166** already exist, an error is returned.</dd>)^ 3167** 3168** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3169** <dd>The database is opened for reading and writing if possible, or reading 3170** only if the file is write protected by the operating system. In either 3171** case the database must already exist, otherwise an error is returned.</dd>)^ 3172** 3173** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3174** <dd>The database is opened for reading and writing, and is created if 3175** it does not already exist. This is the behavior that is always used for 3176** sqlite3_open() and sqlite3_open16().</dd>)^ 3177** </dl> 3178** 3179** If the 3rd parameter to sqlite3_open_v2() is not one of the 3180** combinations shown above optionally combined with other 3181** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3182** then the behavior is undefined. 3183** 3184** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 3185** opens in the multi-thread [threading mode] as long as the single-thread 3186** mode has not been set at compile-time or start-time. ^If the 3187** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 3188** in the serialized [threading mode] unless single-thread was 3189** previously selected at compile-time or start-time. 3190** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 3191** eligible to use [shared cache mode], regardless of whether or not shared 3192** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 3193** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 3194** participate in [shared cache mode] even if it is enabled. 3195** 3196** ^The fourth parameter to sqlite3_open_v2() is the name of the 3197** [sqlite3_vfs] object that defines the operating system interface that 3198** the new database connection should use. ^If the fourth parameter is 3199** a NULL pointer then the default [sqlite3_vfs] object is used. 3200** 3201** ^If the filename is ":memory:", then a private, temporary in-memory database 3202** is created for the connection. ^This in-memory database will vanish when 3203** the database connection is closed. Future versions of SQLite might 3204** make use of additional special filenames that begin with the ":" character. 3205** It is recommended that when a database filename actually does begin with 3206** a ":" character you should prefix the filename with a pathname such as 3207** "./" to avoid ambiguity. 3208** 3209** ^If the filename is an empty string, then a private, temporary 3210** on-disk database will be created. ^This private database will be 3211** automatically deleted as soon as the database connection is closed. 3212** 3213** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3214** 3215** ^If [URI filename] interpretation is enabled, and the filename argument 3216** begins with "file:", then the filename is interpreted as a URI. ^URI 3217** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3218** set in the third argument to sqlite3_open_v2(), or if it has 3219** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3220** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3221** URI filename interpretation is turned off 3222** by default, but future releases of SQLite might enable URI filename 3223** interpretation by default. See "[URI filenames]" for additional 3224** information. 3225** 3226** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3227** authority, then it must be either an empty string or the string 3228** "localhost". ^If the authority is not an empty string or "localhost", an 3229** error is returned to the caller. ^The fragment component of a URI, if 3230** present, is ignored. 3231** 3232** ^SQLite uses the path component of the URI as the name of the disk file 3233** which contains the database. ^If the path begins with a '/' character, 3234** then it is interpreted as an absolute path. ^If the path does not begin 3235** with a '/' (meaning that the authority section is omitted from the URI) 3236** then the path is interpreted as a relative path. 3237** ^(On windows, the first component of an absolute path 3238** is a drive specification (e.g. "C:").)^ 3239** 3240** [[core URI query parameters]] 3241** The query component of a URI may contain parameters that are interpreted 3242** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3243** SQLite and its built-in [VFSes] interpret the 3244** following query parameters: 3245** 3246** <ul> 3247** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3248** a VFS object that provides the operating system interface that should 3249** be used to access the database file on disk. ^If this option is set to 3250** an empty string the default VFS object is used. ^Specifying an unknown 3251** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3252** present, then the VFS specified by the option takes precedence over 3253** the value passed as the fourth parameter to sqlite3_open_v2(). 3254** 3255** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3256** "rwc", or "memory". Attempting to set it to any other value is 3257** an error)^. 3258** ^If "ro" is specified, then the database is opened for read-only 3259** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3260** third argument to sqlite3_open_v2(). ^If the mode option is set to 3261** "rw", then the database is opened for read-write (but not create) 3262** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3263** been set. ^Value "rwc" is equivalent to setting both 3264** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3265** set to "memory" then a pure [in-memory database] that never reads 3266** or writes from disk is used. ^It is an error to specify a value for 3267** the mode parameter that is less restrictive than that specified by 3268** the flags passed in the third parameter to sqlite3_open_v2(). 3269** 3270** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3271** "private". ^Setting it to "shared" is equivalent to setting the 3272** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3273** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3274** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3275** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3276** a URI filename, its value overrides any behavior requested by setting 3277** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3278** 3279** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3280** [powersafe overwrite] property does or does not apply to the 3281** storage media on which the database file resides. 3282** 3283** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3284** which if set disables file locking in rollback journal modes. This 3285** is useful for accessing a database on a filesystem that does not 3286** support locking. Caution: Database corruption might result if two 3287** or more processes write to the same database and any one of those 3288** processes uses nolock=1. 3289** 3290** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3291** parameter that indicates that the database file is stored on 3292** read-only media. ^When immutable is set, SQLite assumes that the 3293** database file cannot be changed, even by a process with higher 3294** privilege, and so the database is opened read-only and all locking 3295** and change detection is disabled. Caution: Setting the immutable 3296** property on a database file that does in fact change can result 3297** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3298** See also: [SQLITE_IOCAP_IMMUTABLE]. 3299** 3300** </ul> 3301** 3302** ^Specifying an unknown parameter in the query component of a URI is not an 3303** error. Future versions of SQLite might understand additional query 3304** parameters. See "[query parameters with special meaning to SQLite]" for 3305** additional information. 3306** 3307** [[URI filename examples]] <h3>URI filename examples</h3> 3308** 3309** <table border="1" align=center cellpadding=5> 3310** <tr><th> URI filenames <th> Results 3311** <tr><td> file:data.db <td> 3312** Open the file "data.db" in the current directory. 3313** <tr><td> file:/home/fred/data.db<br> 3314** file:///home/fred/data.db <br> 3315** file://localhost/home/fred/data.db <br> <td> 3316** Open the database file "/home/fred/data.db". 3317** <tr><td> file://darkstar/home/fred/data.db <td> 3318** An error. "darkstar" is not a recognized authority. 3319** <tr><td style="white-space:nowrap"> 3320** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3321** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3322** C:. Note that the %20 escaping in this example is not strictly 3323** necessary - space characters can be used literally 3324** in URI filenames. 3325** <tr><td> file:data.db?mode=ro&cache=private <td> 3326** Open file "data.db" in the current directory for read-only access. 3327** Regardless of whether or not shared-cache mode is enabled by 3328** default, use a private cache. 3329** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3330** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3331** that uses dot-files in place of posix advisory locking. 3332** <tr><td> file:data.db?mode=readonly <td> 3333** An error. "readonly" is not a valid option for the "mode" parameter. 3334** </table> 3335** 3336** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3337** query components of a URI. A hexadecimal escape sequence consists of a 3338** percent sign - "%" - followed by exactly two hexadecimal digits 3339** specifying an octet value. ^Before the path or query components of a 3340** URI filename are interpreted, they are encoded using UTF-8 and all 3341** hexadecimal escape sequences replaced by a single byte containing the 3342** corresponding octet. If this process generates an invalid UTF-8 encoding, 3343** the results are undefined. 3344** 3345** <b>Note to Windows users:</b> The encoding used for the filename argument 3346** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3347** codepage is currently defined. Filenames containing international 3348** characters must be converted to UTF-8 prior to passing them into 3349** sqlite3_open() or sqlite3_open_v2(). 3350** 3351** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3352** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3353** features that require the use of temporary files may fail. 3354** 3355** See also: [sqlite3_temp_directory] 3356*/ 3357int sqlite3_open( 3358 const char *filename, /* Database filename (UTF-8) */ 3359 sqlite3 **ppDb /* OUT: SQLite db handle */ 3360); 3361int sqlite3_open16( 3362 const void *filename, /* Database filename (UTF-16) */ 3363 sqlite3 **ppDb /* OUT: SQLite db handle */ 3364); 3365int sqlite3_open_v2( 3366 const char *filename, /* Database filename (UTF-8) */ 3367 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3368 int flags, /* Flags */ 3369 const char *zVfs /* Name of VFS module to use */ 3370); 3371 3372/* 3373** CAPI3REF: Obtain Values For URI Parameters 3374** 3375** These are utility routines, useful to VFS implementations, that check 3376** to see if a database file was a URI that contained a specific query 3377** parameter, and if so obtains the value of that query parameter. 3378** 3379** If F is the database filename pointer passed into the xOpen() method of 3380** a VFS implementation when the flags parameter to xOpen() has one or 3381** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3382** P is the name of the query parameter, then 3383** sqlite3_uri_parameter(F,P) returns the value of the P 3384** parameter if it exists or a NULL pointer if P does not appear as a 3385** query parameter on F. If P is a query parameter of F 3386** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3387** a pointer to an empty string. 3388** 3389** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3390** parameter and returns true (1) or false (0) according to the value 3391** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3392** value of query parameter P is one of "yes", "true", or "on" in any 3393** case or if the value begins with a non-zero number. The 3394** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3395** query parameter P is one of "no", "false", or "off" in any case or 3396** if the value begins with a numeric zero. If P is not a query 3397** parameter on F or if the value of P is does not match any of the 3398** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3399** 3400** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3401** 64-bit signed integer and returns that integer, or D if P does not 3402** exist. If the value of P is something other than an integer, then 3403** zero is returned. 3404** 3405** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3406** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3407** is not a database file pathname pointer that SQLite passed into the xOpen 3408** VFS method, then the behavior of this routine is undefined and probably 3409** undesirable. 3410*/ 3411const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3412int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3413sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3414 3415 3416/* 3417** CAPI3REF: Error Codes And Messages 3418** METHOD: sqlite3 3419** 3420** ^If the most recent sqlite3_* API call associated with 3421** [database connection] D failed, then the sqlite3_errcode(D) interface 3422** returns the numeric [result code] or [extended result code] for that 3423** API call. 3424** ^The sqlite3_extended_errcode() 3425** interface is the same except that it always returns the 3426** [extended result code] even when extended result codes are 3427** disabled. 3428** 3429** The values returned by sqlite3_errcode() and/or 3430** sqlite3_extended_errcode() might change with each API call. 3431** Except, there are some interfaces that are guaranteed to never 3432** change the value of the error code. The error-code preserving 3433** interfaces are: 3434** 3435** <ul> 3436** <li> sqlite3_errcode() 3437** <li> sqlite3_extended_errcode() 3438** <li> sqlite3_errmsg() 3439** <li> sqlite3_errmsg16() 3440** </ul> 3441** 3442** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3443** text that describes the error, as either UTF-8 or UTF-16 respectively. 3444** ^(Memory to hold the error message string is managed internally. 3445** The application does not need to worry about freeing the result. 3446** However, the error string might be overwritten or deallocated by 3447** subsequent calls to other SQLite interface functions.)^ 3448** 3449** ^The sqlite3_errstr() interface returns the English-language text 3450** that describes the [result code], as UTF-8. 3451** ^(Memory to hold the error message string is managed internally 3452** and must not be freed by the application)^. 3453** 3454** When the serialized [threading mode] is in use, it might be the 3455** case that a second error occurs on a separate thread in between 3456** the time of the first error and the call to these interfaces. 3457** When that happens, the second error will be reported since these 3458** interfaces always report the most recent result. To avoid 3459** this, each thread can obtain exclusive use of the [database connection] D 3460** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3461** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3462** all calls to the interfaces listed here are completed. 3463** 3464** If an interface fails with SQLITE_MISUSE, that means the interface 3465** was invoked incorrectly by the application. In that case, the 3466** error code and message may or may not be set. 3467*/ 3468int sqlite3_errcode(sqlite3 *db); 3469int sqlite3_extended_errcode(sqlite3 *db); 3470const char *sqlite3_errmsg(sqlite3*); 3471const void *sqlite3_errmsg16(sqlite3*); 3472const char *sqlite3_errstr(int); 3473 3474/* 3475** CAPI3REF: Prepared Statement Object 3476** KEYWORDS: {prepared statement} {prepared statements} 3477** 3478** An instance of this object represents a single SQL statement that 3479** has been compiled into binary form and is ready to be evaluated. 3480** 3481** Think of each SQL statement as a separate computer program. The 3482** original SQL text is source code. A prepared statement object 3483** is the compiled object code. All SQL must be converted into a 3484** prepared statement before it can be run. 3485** 3486** The life-cycle of a prepared statement object usually goes like this: 3487** 3488** <ol> 3489** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3490** <li> Bind values to [parameters] using the sqlite3_bind_*() 3491** interfaces. 3492** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3493** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3494** to step 2. Do this zero or more times. 3495** <li> Destroy the object using [sqlite3_finalize()]. 3496** </ol> 3497*/ 3498typedef struct sqlite3_stmt sqlite3_stmt; 3499 3500/* 3501** CAPI3REF: Run-time Limits 3502** METHOD: sqlite3 3503** 3504** ^(This interface allows the size of various constructs to be limited 3505** on a connection by connection basis. The first parameter is the 3506** [database connection] whose limit is to be set or queried. The 3507** second parameter is one of the [limit categories] that define a 3508** class of constructs to be size limited. The third parameter is the 3509** new limit for that construct.)^ 3510** 3511** ^If the new limit is a negative number, the limit is unchanged. 3512** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3513** [limits | hard upper bound] 3514** set at compile-time by a C preprocessor macro called 3515** [limits | SQLITE_MAX_<i>NAME</i>]. 3516** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3517** ^Attempts to increase a limit above its hard upper bound are 3518** silently truncated to the hard upper bound. 3519** 3520** ^Regardless of whether or not the limit was changed, the 3521** [sqlite3_limit()] interface returns the prior value of the limit. 3522** ^Hence, to find the current value of a limit without changing it, 3523** simply invoke this interface with the third parameter set to -1. 3524** 3525** Run-time limits are intended for use in applications that manage 3526** both their own internal database and also databases that are controlled 3527** by untrusted external sources. An example application might be a 3528** web browser that has its own databases for storing history and 3529** separate databases controlled by JavaScript applications downloaded 3530** off the Internet. The internal databases can be given the 3531** large, default limits. Databases managed by external sources can 3532** be given much smaller limits designed to prevent a denial of service 3533** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3534** interface to further control untrusted SQL. The size of the database 3535** created by an untrusted script can be contained using the 3536** [max_page_count] [PRAGMA]. 3537** 3538** New run-time limit categories may be added in future releases. 3539*/ 3540int sqlite3_limit(sqlite3*, int id, int newVal); 3541 3542/* 3543** CAPI3REF: Run-Time Limit Categories 3544** KEYWORDS: {limit category} {*limit categories} 3545** 3546** These constants define various performance limits 3547** that can be lowered at run-time using [sqlite3_limit()]. 3548** The synopsis of the meanings of the various limits is shown below. 3549** Additional information is available at [limits | Limits in SQLite]. 3550** 3551** <dl> 3552** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3553** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3554** 3555** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3556** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3557** 3558** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3559** <dd>The maximum number of columns in a table definition or in the 3560** result set of a [SELECT] or the maximum number of columns in an index 3561** or in an ORDER BY or GROUP BY clause.</dd>)^ 3562** 3563** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3564** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3565** 3566** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3567** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3568** 3569** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3570** <dd>The maximum number of instructions in a virtual machine program 3571** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3572** the equivalent tries to allocate space for more than this many opcodes 3573** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3574** 3575** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3576** <dd>The maximum number of arguments on a function.</dd>)^ 3577** 3578** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3579** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3580** 3581** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3582** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3583** <dd>The maximum length of the pattern argument to the [LIKE] or 3584** [GLOB] operators.</dd>)^ 3585** 3586** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3587** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3588** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3589** 3590** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3591** <dd>The maximum depth of recursion for triggers.</dd>)^ 3592** 3593** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3594** <dd>The maximum number of auxiliary worker threads that a single 3595** [prepared statement] may start.</dd>)^ 3596** </dl> 3597*/ 3598#define SQLITE_LIMIT_LENGTH 0 3599#define SQLITE_LIMIT_SQL_LENGTH 1 3600#define SQLITE_LIMIT_COLUMN 2 3601#define SQLITE_LIMIT_EXPR_DEPTH 3 3602#define SQLITE_LIMIT_COMPOUND_SELECT 4 3603#define SQLITE_LIMIT_VDBE_OP 5 3604#define SQLITE_LIMIT_FUNCTION_ARG 6 3605#define SQLITE_LIMIT_ATTACHED 7 3606#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3607#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3608#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3609#define SQLITE_LIMIT_WORKER_THREADS 11 3610 3611/* 3612** CAPI3REF: Prepare Flags 3613** 3614** These constants define various flags that can be passed into 3615** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3616** [sqlite3_prepare16_v3()] interfaces. 3617** 3618** New flags may be added in future releases of SQLite. 3619** 3620** <dl> 3621** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3622** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3623** that the prepared statement will be retained for a long time and 3624** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3625** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3626** be used just once or at most a few times and then destroyed using 3627** [sqlite3_finalize()] relatively soon. The current implementation acts 3628** on this hint by avoiding the use of [lookaside memory] so as not to 3629** deplete the limited store of lookaside memory. Future versions of 3630** SQLite may act on this hint differently. 3631** 3632** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt> 3633** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used 3634** to be required for any prepared statement that wanted to use the 3635** [sqlite3_normalized_sql()] interface. However, the 3636** [sqlite3_normalized_sql()] interface is now available to all 3637** prepared statements, regardless of whether or not they use this 3638** flag. 3639** 3640** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt> 3641** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler 3642** to return an error (error code SQLITE_ERROR) if the statement uses 3643** any virtual tables. 3644** </dl> 3645*/ 3646#define SQLITE_PREPARE_PERSISTENT 0x01 3647#define SQLITE_PREPARE_NORMALIZE 0x02 3648#define SQLITE_PREPARE_NO_VTAB 0x04 3649 3650/* 3651** CAPI3REF: Compiling An SQL Statement 3652** KEYWORDS: {SQL statement compiler} 3653** METHOD: sqlite3 3654** CONSTRUCTOR: sqlite3_stmt 3655** 3656** To execute an SQL statement, it must first be compiled into a byte-code 3657** program using one of these routines. Or, in other words, these routines 3658** are constructors for the [prepared statement] object. 3659** 3660** The preferred routine to use is [sqlite3_prepare_v2()]. The 3661** [sqlite3_prepare()] interface is legacy and should be avoided. 3662** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3663** for special purposes. 3664** 3665** The use of the UTF-8 interfaces is preferred, as SQLite currently 3666** does all parsing using UTF-8. The UTF-16 interfaces are provided 3667** as a convenience. The UTF-16 interfaces work by converting the 3668** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3669** 3670** The first argument, "db", is a [database connection] obtained from a 3671** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3672** [sqlite3_open16()]. The database connection must not have been closed. 3673** 3674** The second argument, "zSql", is the statement to be compiled, encoded 3675** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 3676** and sqlite3_prepare_v3() 3677** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 3678** and sqlite3_prepare16_v3() use UTF-16. 3679** 3680** ^If the nByte argument is negative, then zSql is read up to the 3681** first zero terminator. ^If nByte is positive, then it is the 3682** number of bytes read from zSql. ^If nByte is zero, then no prepared 3683** statement is generated. 3684** If the caller knows that the supplied string is nul-terminated, then 3685** there is a small performance advantage to passing an nByte parameter that 3686** is the number of bytes in the input string <i>including</i> 3687** the nul-terminator. 3688** 3689** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3690** past the end of the first SQL statement in zSql. These routines only 3691** compile the first statement in zSql, so *pzTail is left pointing to 3692** what remains uncompiled. 3693** 3694** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3695** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3696** to NULL. ^If the input text contains no SQL (if the input is an empty 3697** string or a comment) then *ppStmt is set to NULL. 3698** The calling procedure is responsible for deleting the compiled 3699** SQL statement using [sqlite3_finalize()] after it has finished with it. 3700** ppStmt may not be NULL. 3701** 3702** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3703** otherwise an [error code] is returned. 3704** 3705** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 3706** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 3707** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 3708** are retained for backwards compatibility, but their use is discouraged. 3709** ^In the "vX" interfaces, the prepared statement 3710** that is returned (the [sqlite3_stmt] object) contains a copy of the 3711** original SQL text. This causes the [sqlite3_step()] interface to 3712** behave differently in three ways: 3713** 3714** <ol> 3715** <li> 3716** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3717** always used to do, [sqlite3_step()] will automatically recompile the SQL 3718** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3719** retries will occur before sqlite3_step() gives up and returns an error. 3720** </li> 3721** 3722** <li> 3723** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3724** [error codes] or [extended error codes]. ^The legacy behavior was that 3725** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3726** and the application would have to make a second call to [sqlite3_reset()] 3727** in order to find the underlying cause of the problem. With the "v2" prepare 3728** interfaces, the underlying reason for the error is returned immediately. 3729** </li> 3730** 3731** <li> 3732** ^If the specific value bound to [parameter | host parameter] in the 3733** WHERE clause might influence the choice of query plan for a statement, 3734** then the statement will be automatically recompiled, as if there had been 3735** a schema change, on the first [sqlite3_step()] call following any change 3736** to the [sqlite3_bind_text | bindings] of that [parameter]. 3737** ^The specific value of WHERE-clause [parameter] might influence the 3738** choice of query plan if the parameter is the left-hand side of a [LIKE] 3739** or [GLOB] operator or if the parameter is compared to an indexed column 3740** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3741** </li> 3742** </ol> 3743** 3744** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 3745** the extra prepFlags parameter, which is a bit array consisting of zero or 3746** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 3747** sqlite3_prepare_v2() interface works exactly the same as 3748** sqlite3_prepare_v3() with a zero prepFlags parameter. 3749*/ 3750int sqlite3_prepare( 3751 sqlite3 *db, /* Database handle */ 3752 const char *zSql, /* SQL statement, UTF-8 encoded */ 3753 int nByte, /* Maximum length of zSql in bytes. */ 3754 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3755 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3756); 3757int sqlite3_prepare_v2( 3758 sqlite3 *db, /* Database handle */ 3759 const char *zSql, /* SQL statement, UTF-8 encoded */ 3760 int nByte, /* Maximum length of zSql in bytes. */ 3761 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3762 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3763); 3764int sqlite3_prepare_v3( 3765 sqlite3 *db, /* Database handle */ 3766 const char *zSql, /* SQL statement, UTF-8 encoded */ 3767 int nByte, /* Maximum length of zSql in bytes. */ 3768 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3769 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3770 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3771); 3772int sqlite3_prepare16( 3773 sqlite3 *db, /* Database handle */ 3774 const void *zSql, /* SQL statement, UTF-16 encoded */ 3775 int nByte, /* Maximum length of zSql in bytes. */ 3776 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3777 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3778); 3779int sqlite3_prepare16_v2( 3780 sqlite3 *db, /* Database handle */ 3781 const void *zSql, /* SQL statement, UTF-16 encoded */ 3782 int nByte, /* Maximum length of zSql in bytes. */ 3783 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3784 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3785); 3786int sqlite3_prepare16_v3( 3787 sqlite3 *db, /* Database handle */ 3788 const void *zSql, /* SQL statement, UTF-16 encoded */ 3789 int nByte, /* Maximum length of zSql in bytes. */ 3790 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3791 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3792 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3793); 3794 3795/* 3796** CAPI3REF: Retrieving Statement SQL 3797** METHOD: sqlite3_stmt 3798** 3799** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 3800** SQL text used to create [prepared statement] P if P was 3801** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 3802** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 3803** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 3804** string containing the SQL text of prepared statement P with 3805** [bound parameters] expanded. 3806** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8 3807** string containing the normalized SQL text of prepared statement P. The 3808** semantics used to normalize a SQL statement are unspecified and subject 3809** to change. At a minimum, literal values will be replaced with suitable 3810** placeholders. 3811** 3812** ^(For example, if a prepared statement is created using the SQL 3813** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 3814** and parameter :xyz is unbound, then sqlite3_sql() will return 3815** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 3816** will return "SELECT 2345,NULL".)^ 3817** 3818** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 3819** is available to hold the result, or if the result would exceed the 3820** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 3821** 3822** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 3823** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 3824** option causes sqlite3_expanded_sql() to always return NULL. 3825** 3826** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P) 3827** are managed by SQLite and are automatically freed when the prepared 3828** statement is finalized. 3829** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 3830** is obtained from [sqlite3_malloc()] and must be free by the application 3831** by passing it to [sqlite3_free()]. 3832*/ 3833const char *sqlite3_sql(sqlite3_stmt *pStmt); 3834char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 3835const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt); 3836 3837/* 3838** CAPI3REF: Determine If An SQL Statement Writes The Database 3839** METHOD: sqlite3_stmt 3840** 3841** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3842** and only if the [prepared statement] X makes no direct changes to 3843** the content of the database file. 3844** 3845** Note that [application-defined SQL functions] or 3846** [virtual tables] might change the database indirectly as a side effect. 3847** ^(For example, if an application defines a function "eval()" that 3848** calls [sqlite3_exec()], then the following SQL statement would 3849** change the database file through side-effects: 3850** 3851** <blockquote><pre> 3852** SELECT eval('DELETE FROM t1') FROM t2; 3853** </pre></blockquote> 3854** 3855** But because the [SELECT] statement does not change the database file 3856** directly, sqlite3_stmt_readonly() would still return true.)^ 3857** 3858** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3859** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3860** since the statements themselves do not actually modify the database but 3861** rather they control the timing of when other statements modify the 3862** database. ^The [ATTACH] and [DETACH] statements also cause 3863** sqlite3_stmt_readonly() to return true since, while those statements 3864** change the configuration of a database connection, they do not make 3865** changes to the content of the database files on disk. 3866** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 3867** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 3868** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 3869** sqlite3_stmt_readonly() returns false for those commands. 3870*/ 3871int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3872 3873/* 3874** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3875** METHOD: sqlite3_stmt 3876** 3877** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3878** [prepared statement] S has been stepped at least once using 3879** [sqlite3_step(S)] but has neither run to completion (returned 3880** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3881** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3882** interface returns false if S is a NULL pointer. If S is not a 3883** NULL pointer and is not a pointer to a valid [prepared statement] 3884** object, then the behavior is undefined and probably undesirable. 3885** 3886** This interface can be used in combination [sqlite3_next_stmt()] 3887** to locate all prepared statements associated with a database 3888** connection that are in need of being reset. This can be used, 3889** for example, in diagnostic routines to search for prepared 3890** statements that are holding a transaction open. 3891*/ 3892int sqlite3_stmt_busy(sqlite3_stmt*); 3893 3894/* 3895** CAPI3REF: Dynamically Typed Value Object 3896** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3897** 3898** SQLite uses the sqlite3_value object to represent all values 3899** that can be stored in a database table. SQLite uses dynamic typing 3900** for the values it stores. ^Values stored in sqlite3_value objects 3901** can be integers, floating point values, strings, BLOBs, or NULL. 3902** 3903** An sqlite3_value object may be either "protected" or "unprotected". 3904** Some interfaces require a protected sqlite3_value. Other interfaces 3905** will accept either a protected or an unprotected sqlite3_value. 3906** Every interface that accepts sqlite3_value arguments specifies 3907** whether or not it requires a protected sqlite3_value. The 3908** [sqlite3_value_dup()] interface can be used to construct a new 3909** protected sqlite3_value from an unprotected sqlite3_value. 3910** 3911** The terms "protected" and "unprotected" refer to whether or not 3912** a mutex is held. An internal mutex is held for a protected 3913** sqlite3_value object but no mutex is held for an unprotected 3914** sqlite3_value object. If SQLite is compiled to be single-threaded 3915** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3916** or if SQLite is run in one of reduced mutex modes 3917** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3918** then there is no distinction between protected and unprotected 3919** sqlite3_value objects and they can be used interchangeably. However, 3920** for maximum code portability it is recommended that applications 3921** still make the distinction between protected and unprotected 3922** sqlite3_value objects even when not strictly required. 3923** 3924** ^The sqlite3_value objects that are passed as parameters into the 3925** implementation of [application-defined SQL functions] are protected. 3926** ^The sqlite3_value object returned by 3927** [sqlite3_column_value()] is unprotected. 3928** Unprotected sqlite3_value objects may only be used as arguments 3929** to [sqlite3_result_value()], [sqlite3_bind_value()], and 3930** [sqlite3_value_dup()]. 3931** The [sqlite3_value_blob | sqlite3_value_type()] family of 3932** interfaces require protected sqlite3_value objects. 3933*/ 3934typedef struct sqlite3_value sqlite3_value; 3935 3936/* 3937** CAPI3REF: SQL Function Context Object 3938** 3939** The context in which an SQL function executes is stored in an 3940** sqlite3_context object. ^A pointer to an sqlite3_context object 3941** is always first parameter to [application-defined SQL functions]. 3942** The application-defined SQL function implementation will pass this 3943** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3944** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3945** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3946** and/or [sqlite3_set_auxdata()]. 3947*/ 3948typedef struct sqlite3_context sqlite3_context; 3949 3950/* 3951** CAPI3REF: Binding Values To Prepared Statements 3952** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3953** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3954** METHOD: sqlite3_stmt 3955** 3956** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3957** literals may be replaced by a [parameter] that matches one of following 3958** templates: 3959** 3960** <ul> 3961** <li> ? 3962** <li> ?NNN 3963** <li> :VVV 3964** <li> @VVV 3965** <li> $VVV 3966** </ul> 3967** 3968** In the templates above, NNN represents an integer literal, 3969** and VVV represents an alphanumeric identifier.)^ ^The values of these 3970** parameters (also called "host parameter names" or "SQL parameters") 3971** can be set using the sqlite3_bind_*() routines defined here. 3972** 3973** ^The first argument to the sqlite3_bind_*() routines is always 3974** a pointer to the [sqlite3_stmt] object returned from 3975** [sqlite3_prepare_v2()] or its variants. 3976** 3977** ^The second argument is the index of the SQL parameter to be set. 3978** ^The leftmost SQL parameter has an index of 1. ^When the same named 3979** SQL parameter is used more than once, second and subsequent 3980** occurrences have the same index as the first occurrence. 3981** ^The index for named parameters can be looked up using the 3982** [sqlite3_bind_parameter_index()] API if desired. ^The index 3983** for "?NNN" parameters is the value of NNN. 3984** ^The NNN value must be between 1 and the [sqlite3_limit()] 3985** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3986** 3987** ^The third argument is the value to bind to the parameter. 3988** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3989** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3990** is ignored and the end result is the same as sqlite3_bind_null(). 3991** 3992** ^(In those routines that have a fourth argument, its value is the 3993** number of bytes in the parameter. To be clear: the value is the 3994** number of <u>bytes</u> in the value, not the number of characters.)^ 3995** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3996** is negative, then the length of the string is 3997** the number of bytes up to the first zero terminator. 3998** If the fourth parameter to sqlite3_bind_blob() is negative, then 3999** the behavior is undefined. 4000** If a non-negative fourth parameter is provided to sqlite3_bind_text() 4001** or sqlite3_bind_text16() or sqlite3_bind_text64() then 4002** that parameter must be the byte offset 4003** where the NUL terminator would occur assuming the string were NUL 4004** terminated. If any NUL characters occur at byte offsets less than 4005** the value of the fourth parameter then the resulting string value will 4006** contain embedded NULs. The result of expressions involving strings 4007** with embedded NULs is undefined. 4008** 4009** ^The fifth argument to the BLOB and string binding interfaces 4010** is a destructor used to dispose of the BLOB or 4011** string after SQLite has finished with it. ^The destructor is called 4012** to dispose of the BLOB or string even if the call to bind API fails. 4013** ^If the fifth argument is 4014** the special value [SQLITE_STATIC], then SQLite assumes that the 4015** information is in static, unmanaged space and does not need to be freed. 4016** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 4017** SQLite makes its own private copy of the data immediately, before 4018** the sqlite3_bind_*() routine returns. 4019** 4020** ^The sixth argument to sqlite3_bind_text64() must be one of 4021** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 4022** to specify the encoding of the text in the third parameter. If 4023** the sixth argument to sqlite3_bind_text64() is not one of the 4024** allowed values shown above, or if the text encoding is different 4025** from the encoding specified by the sixth parameter, then the behavior 4026** is undefined. 4027** 4028** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 4029** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 4030** (just an integer to hold its size) while it is being processed. 4031** Zeroblobs are intended to serve as placeholders for BLOBs whose 4032** content is later written using 4033** [sqlite3_blob_open | incremental BLOB I/O] routines. 4034** ^A negative value for the zeroblob results in a zero-length BLOB. 4035** 4036** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 4037** [prepared statement] S to have an SQL value of NULL, but to also be 4038** associated with the pointer P of type T. ^D is either a NULL pointer or 4039** a pointer to a destructor function for P. ^SQLite will invoke the 4040** destructor D with a single argument of P when it is finished using 4041** P. The T parameter should be a static string, preferably a string 4042** literal. The sqlite3_bind_pointer() routine is part of the 4043** [pointer passing interface] added for SQLite 3.20.0. 4044** 4045** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 4046** for the [prepared statement] or with a prepared statement for which 4047** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 4048** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 4049** routine is passed a [prepared statement] that has been finalized, the 4050** result is undefined and probably harmful. 4051** 4052** ^Bindings are not cleared by the [sqlite3_reset()] routine. 4053** ^Unbound parameters are interpreted as NULL. 4054** 4055** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 4056** [error code] if anything goes wrong. 4057** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 4058** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 4059** [SQLITE_MAX_LENGTH]. 4060** ^[SQLITE_RANGE] is returned if the parameter 4061** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 4062** 4063** See also: [sqlite3_bind_parameter_count()], 4064** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 4065*/ 4066int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 4067int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 4068 void(*)(void*)); 4069int sqlite3_bind_double(sqlite3_stmt*, int, double); 4070int sqlite3_bind_int(sqlite3_stmt*, int, int); 4071int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 4072int sqlite3_bind_null(sqlite3_stmt*, int); 4073int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 4074int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 4075int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 4076 void(*)(void*), unsigned char encoding); 4077int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 4078int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 4079int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 4080int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 4081 4082/* 4083** CAPI3REF: Number Of SQL Parameters 4084** METHOD: sqlite3_stmt 4085** 4086** ^This routine can be used to find the number of [SQL parameters] 4087** in a [prepared statement]. SQL parameters are tokens of the 4088** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 4089** placeholders for values that are [sqlite3_bind_blob | bound] 4090** to the parameters at a later time. 4091** 4092** ^(This routine actually returns the index of the largest (rightmost) 4093** parameter. For all forms except ?NNN, this will correspond to the 4094** number of unique parameters. If parameters of the ?NNN form are used, 4095** there may be gaps in the list.)^ 4096** 4097** See also: [sqlite3_bind_blob|sqlite3_bind()], 4098** [sqlite3_bind_parameter_name()], and 4099** [sqlite3_bind_parameter_index()]. 4100*/ 4101int sqlite3_bind_parameter_count(sqlite3_stmt*); 4102 4103/* 4104** CAPI3REF: Name Of A Host Parameter 4105** METHOD: sqlite3_stmt 4106** 4107** ^The sqlite3_bind_parameter_name(P,N) interface returns 4108** the name of the N-th [SQL parameter] in the [prepared statement] P. 4109** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 4110** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 4111** respectively. 4112** In other words, the initial ":" or "$" or "@" or "?" 4113** is included as part of the name.)^ 4114** ^Parameters of the form "?" without a following integer have no name 4115** and are referred to as "nameless" or "anonymous parameters". 4116** 4117** ^The first host parameter has an index of 1, not 0. 4118** 4119** ^If the value N is out of range or if the N-th parameter is 4120** nameless, then NULL is returned. ^The returned string is 4121** always in UTF-8 encoding even if the named parameter was 4122** originally specified as UTF-16 in [sqlite3_prepare16()], 4123** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4124** 4125** See also: [sqlite3_bind_blob|sqlite3_bind()], 4126** [sqlite3_bind_parameter_count()], and 4127** [sqlite3_bind_parameter_index()]. 4128*/ 4129const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 4130 4131/* 4132** CAPI3REF: Index Of A Parameter With A Given Name 4133** METHOD: sqlite3_stmt 4134** 4135** ^Return the index of an SQL parameter given its name. ^The 4136** index value returned is suitable for use as the second 4137** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4138** is returned if no matching parameter is found. ^The parameter 4139** name must be given in UTF-8 even if the original statement 4140** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4141** [sqlite3_prepare16_v3()]. 4142** 4143** See also: [sqlite3_bind_blob|sqlite3_bind()], 4144** [sqlite3_bind_parameter_count()], and 4145** [sqlite3_bind_parameter_name()]. 4146*/ 4147int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4148 4149/* 4150** CAPI3REF: Reset All Bindings On A Prepared Statement 4151** METHOD: sqlite3_stmt 4152** 4153** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4154** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4155** ^Use this routine to reset all host parameters to NULL. 4156*/ 4157int sqlite3_clear_bindings(sqlite3_stmt*); 4158 4159/* 4160** CAPI3REF: Number Of Columns In A Result Set 4161** METHOD: sqlite3_stmt 4162** 4163** ^Return the number of columns in the result set returned by the 4164** [prepared statement]. ^If this routine returns 0, that means the 4165** [prepared statement] returns no data (for example an [UPDATE]). 4166** ^However, just because this routine returns a positive number does not 4167** mean that one or more rows of data will be returned. ^A SELECT statement 4168** will always have a positive sqlite3_column_count() but depending on the 4169** WHERE clause constraints and the table content, it might return no rows. 4170** 4171** See also: [sqlite3_data_count()] 4172*/ 4173int sqlite3_column_count(sqlite3_stmt *pStmt); 4174 4175/* 4176** CAPI3REF: Column Names In A Result Set 4177** METHOD: sqlite3_stmt 4178** 4179** ^These routines return the name assigned to a particular column 4180** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4181** interface returns a pointer to a zero-terminated UTF-8 string 4182** and sqlite3_column_name16() returns a pointer to a zero-terminated 4183** UTF-16 string. ^The first parameter is the [prepared statement] 4184** that implements the [SELECT] statement. ^The second parameter is the 4185** column number. ^The leftmost column is number 0. 4186** 4187** ^The returned string pointer is valid until either the [prepared statement] 4188** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4189** reprepared by the first call to [sqlite3_step()] for a particular run 4190** or until the next call to 4191** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4192** 4193** ^If sqlite3_malloc() fails during the processing of either routine 4194** (for example during a conversion from UTF-8 to UTF-16) then a 4195** NULL pointer is returned. 4196** 4197** ^The name of a result column is the value of the "AS" clause for 4198** that column, if there is an AS clause. If there is no AS clause 4199** then the name of the column is unspecified and may change from 4200** one release of SQLite to the next. 4201*/ 4202const char *sqlite3_column_name(sqlite3_stmt*, int N); 4203const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4204 4205/* 4206** CAPI3REF: Source Of Data In A Query Result 4207** METHOD: sqlite3_stmt 4208** 4209** ^These routines provide a means to determine the database, table, and 4210** table column that is the origin of a particular result column in 4211** [SELECT] statement. 4212** ^The name of the database or table or column can be returned as 4213** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4214** the database name, the _table_ routines return the table name, and 4215** the origin_ routines return the column name. 4216** ^The returned string is valid until the [prepared statement] is destroyed 4217** using [sqlite3_finalize()] or until the statement is automatically 4218** reprepared by the first call to [sqlite3_step()] for a particular run 4219** or until the same information is requested 4220** again in a different encoding. 4221** 4222** ^The names returned are the original un-aliased names of the 4223** database, table, and column. 4224** 4225** ^The first argument to these interfaces is a [prepared statement]. 4226** ^These functions return information about the Nth result column returned by 4227** the statement, where N is the second function argument. 4228** ^The left-most column is column 0 for these routines. 4229** 4230** ^If the Nth column returned by the statement is an expression or 4231** subquery and is not a column value, then all of these functions return 4232** NULL. ^These routine might also return NULL if a memory allocation error 4233** occurs. ^Otherwise, they return the name of the attached database, table, 4234** or column that query result column was extracted from. 4235** 4236** ^As with all other SQLite APIs, those whose names end with "16" return 4237** UTF-16 encoded strings and the other functions return UTF-8. 4238** 4239** ^These APIs are only available if the library was compiled with the 4240** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4241** 4242** If two or more threads call one or more of these routines against the same 4243** prepared statement and column at the same time then the results are 4244** undefined. 4245** 4246** If two or more threads call one or more 4247** [sqlite3_column_database_name | column metadata interfaces] 4248** for the same [prepared statement] and result column 4249** at the same time then the results are undefined. 4250*/ 4251const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4252const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4253const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4254const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4255const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4256const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4257 4258/* 4259** CAPI3REF: Declared Datatype Of A Query Result 4260** METHOD: sqlite3_stmt 4261** 4262** ^(The first parameter is a [prepared statement]. 4263** If this statement is a [SELECT] statement and the Nth column of the 4264** returned result set of that [SELECT] is a table column (not an 4265** expression or subquery) then the declared type of the table 4266** column is returned.)^ ^If the Nth column of the result set is an 4267** expression or subquery, then a NULL pointer is returned. 4268** ^The returned string is always UTF-8 encoded. 4269** 4270** ^(For example, given the database schema: 4271** 4272** CREATE TABLE t1(c1 VARIANT); 4273** 4274** and the following statement to be compiled: 4275** 4276** SELECT c1 + 1, c1 FROM t1; 4277** 4278** this routine would return the string "VARIANT" for the second result 4279** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4280** 4281** ^SQLite uses dynamic run-time typing. ^So just because a column 4282** is declared to contain a particular type does not mean that the 4283** data stored in that column is of the declared type. SQLite is 4284** strongly typed, but the typing is dynamic not static. ^Type 4285** is associated with individual values, not with the containers 4286** used to hold those values. 4287*/ 4288const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4289const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4290 4291/* 4292** CAPI3REF: Evaluate An SQL Statement 4293** METHOD: sqlite3_stmt 4294** 4295** After a [prepared statement] has been prepared using any of 4296** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4297** or [sqlite3_prepare16_v3()] or one of the legacy 4298** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4299** must be called one or more times to evaluate the statement. 4300** 4301** The details of the behavior of the sqlite3_step() interface depend 4302** on whether the statement was prepared using the newer "vX" interfaces 4303** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4304** [sqlite3_prepare16_v2()] or the older legacy 4305** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4306** new "vX" interface is recommended for new applications but the legacy 4307** interface will continue to be supported. 4308** 4309** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4310** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4311** ^With the "v2" interface, any of the other [result codes] or 4312** [extended result codes] might be returned as well. 4313** 4314** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4315** database locks it needs to do its job. ^If the statement is a [COMMIT] 4316** or occurs outside of an explicit transaction, then you can retry the 4317** statement. If the statement is not a [COMMIT] and occurs within an 4318** explicit transaction then you should rollback the transaction before 4319** continuing. 4320** 4321** ^[SQLITE_DONE] means that the statement has finished executing 4322** successfully. sqlite3_step() should not be called again on this virtual 4323** machine without first calling [sqlite3_reset()] to reset the virtual 4324** machine back to its initial state. 4325** 4326** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4327** is returned each time a new row of data is ready for processing by the 4328** caller. The values may be accessed using the [column access functions]. 4329** sqlite3_step() is called again to retrieve the next row of data. 4330** 4331** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4332** violation) has occurred. sqlite3_step() should not be called again on 4333** the VM. More information may be found by calling [sqlite3_errmsg()]. 4334** ^With the legacy interface, a more specific error code (for example, 4335** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4336** can be obtained by calling [sqlite3_reset()] on the 4337** [prepared statement]. ^In the "v2" interface, 4338** the more specific error code is returned directly by sqlite3_step(). 4339** 4340** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4341** Perhaps it was called on a [prepared statement] that has 4342** already been [sqlite3_finalize | finalized] or on one that had 4343** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4344** be the case that the same database connection is being used by two or 4345** more threads at the same moment in time. 4346** 4347** For all versions of SQLite up to and including 3.6.23.1, a call to 4348** [sqlite3_reset()] was required after sqlite3_step() returned anything 4349** other than [SQLITE_ROW] before any subsequent invocation of 4350** sqlite3_step(). Failure to reset the prepared statement using 4351** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4352** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4353** sqlite3_step() began 4354** calling [sqlite3_reset()] automatically in this circumstance rather 4355** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4356** break because any application that ever receives an SQLITE_MISUSE error 4357** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4358** can be used to restore the legacy behavior. 4359** 4360** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4361** API always returns a generic error code, [SQLITE_ERROR], following any 4362** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4363** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4364** specific [error codes] that better describes the error. 4365** We admit that this is a goofy design. The problem has been fixed 4366** with the "v2" interface. If you prepare all of your SQL statements 4367** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4368** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4369** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4370** then the more specific [error codes] are returned directly 4371** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4372*/ 4373int sqlite3_step(sqlite3_stmt*); 4374 4375/* 4376** CAPI3REF: Number of columns in a result set 4377** METHOD: sqlite3_stmt 4378** 4379** ^The sqlite3_data_count(P) interface returns the number of columns in the 4380** current row of the result set of [prepared statement] P. 4381** ^If prepared statement P does not have results ready to return 4382** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 4383** interfaces) then sqlite3_data_count(P) returns 0. 4384** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4385** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4386** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4387** will return non-zero if previous call to [sqlite3_step](P) returned 4388** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4389** where it always returns zero since each step of that multi-step 4390** pragma returns 0 columns of data. 4391** 4392** See also: [sqlite3_column_count()] 4393*/ 4394int sqlite3_data_count(sqlite3_stmt *pStmt); 4395 4396/* 4397** CAPI3REF: Fundamental Datatypes 4398** KEYWORDS: SQLITE_TEXT 4399** 4400** ^(Every value in SQLite has one of five fundamental datatypes: 4401** 4402** <ul> 4403** <li> 64-bit signed integer 4404** <li> 64-bit IEEE floating point number 4405** <li> string 4406** <li> BLOB 4407** <li> NULL 4408** </ul>)^ 4409** 4410** These constants are codes for each of those types. 4411** 4412** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4413** for a completely different meaning. Software that links against both 4414** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4415** SQLITE_TEXT. 4416*/ 4417#define SQLITE_INTEGER 1 4418#define SQLITE_FLOAT 2 4419#define SQLITE_BLOB 4 4420#define SQLITE_NULL 5 4421#ifdef SQLITE_TEXT 4422# undef SQLITE_TEXT 4423#else 4424# define SQLITE_TEXT 3 4425#endif 4426#define SQLITE3_TEXT 3 4427 4428/* 4429** CAPI3REF: Result Values From A Query 4430** KEYWORDS: {column access functions} 4431** METHOD: sqlite3_stmt 4432** 4433** <b>Summary:</b> 4434** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4435** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4436** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4437** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4438** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4439** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4440** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4441** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4442** [sqlite3_value|unprotected sqlite3_value] object. 4443** <tr><td> <td> <td> 4444** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4445** or a UTF-8 TEXT result in bytes 4446** <tr><td><b>sqlite3_column_bytes16 </b> 4447** <td>→ <td>Size of UTF-16 4448** TEXT in bytes 4449** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4450** datatype of the result 4451** </table></blockquote> 4452** 4453** <b>Details:</b> 4454** 4455** ^These routines return information about a single column of the current 4456** result row of a query. ^In every case the first argument is a pointer 4457** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4458** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4459** and the second argument is the index of the column for which information 4460** should be returned. ^The leftmost column of the result set has the index 0. 4461** ^The number of columns in the result can be determined using 4462** [sqlite3_column_count()]. 4463** 4464** If the SQL statement does not currently point to a valid row, or if the 4465** column index is out of range, the result is undefined. 4466** These routines may only be called when the most recent call to 4467** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4468** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4469** If any of these routines are called after [sqlite3_reset()] or 4470** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4471** something other than [SQLITE_ROW], the results are undefined. 4472** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4473** are called from a different thread while any of these routines 4474** are pending, then the results are undefined. 4475** 4476** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4477** each return the value of a result column in a specific data format. If 4478** the result column is not initially in the requested format (for example, 4479** if the query returns an integer but the sqlite3_column_text() interface 4480** is used to extract the value) then an automatic type conversion is performed. 4481** 4482** ^The sqlite3_column_type() routine returns the 4483** [SQLITE_INTEGER | datatype code] for the initial data type 4484** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4485** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4486** The return value of sqlite3_column_type() can be used to decide which 4487** of the first six interface should be used to extract the column value. 4488** The value returned by sqlite3_column_type() is only meaningful if no 4489** automatic type conversions have occurred for the value in question. 4490** After a type conversion, the result of calling sqlite3_column_type() 4491** is undefined, though harmless. Future 4492** versions of SQLite may change the behavior of sqlite3_column_type() 4493** following a type conversion. 4494** 4495** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4496** or sqlite3_column_bytes16() interfaces can be used to determine the size 4497** of that BLOB or string. 4498** 4499** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4500** routine returns the number of bytes in that BLOB or string. 4501** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4502** the string to UTF-8 and then returns the number of bytes. 4503** ^If the result is a numeric value then sqlite3_column_bytes() uses 4504** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4505** the number of bytes in that string. 4506** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4507** 4508** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4509** routine returns the number of bytes in that BLOB or string. 4510** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4511** the string to UTF-16 and then returns the number of bytes. 4512** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4513** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4514** the number of bytes in that string. 4515** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4516** 4517** ^The values returned by [sqlite3_column_bytes()] and 4518** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4519** of the string. ^For clarity: the values returned by 4520** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4521** bytes in the string, not the number of characters. 4522** 4523** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4524** even empty strings, are always zero-terminated. ^The return 4525** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4526** 4527** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4528** [unprotected sqlite3_value] object. In a multithreaded environment, 4529** an unprotected sqlite3_value object may only be used safely with 4530** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4531** If the [unprotected sqlite3_value] object returned by 4532** [sqlite3_column_value()] is used in any other way, including calls 4533** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4534** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4535** Hence, the sqlite3_column_value() interface 4536** is normally only useful within the implementation of 4537** [application-defined SQL functions] or [virtual tables], not within 4538** top-level application code. 4539** 4540** The these routines may attempt to convert the datatype of the result. 4541** ^For example, if the internal representation is FLOAT and a text result 4542** is requested, [sqlite3_snprintf()] is used internally to perform the 4543** conversion automatically. ^(The following table details the conversions 4544** that are applied: 4545** 4546** <blockquote> 4547** <table border="1"> 4548** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4549** 4550** <tr><td> NULL <td> INTEGER <td> Result is 0 4551** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4552** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4553** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4554** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4555** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4556** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4557** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4558** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4559** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4560** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4561** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4562** <tr><td> TEXT <td> BLOB <td> No change 4563** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4564** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4565** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4566** </table> 4567** </blockquote>)^ 4568** 4569** Note that when type conversions occur, pointers returned by prior 4570** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4571** sqlite3_column_text16() may be invalidated. 4572** Type conversions and pointer invalidations might occur 4573** in the following cases: 4574** 4575** <ul> 4576** <li> The initial content is a BLOB and sqlite3_column_text() or 4577** sqlite3_column_text16() is called. A zero-terminator might 4578** need to be added to the string.</li> 4579** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4580** sqlite3_column_text16() is called. The content must be converted 4581** to UTF-16.</li> 4582** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4583** sqlite3_column_text() is called. The content must be converted 4584** to UTF-8.</li> 4585** </ul> 4586** 4587** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4588** not invalidate a prior pointer, though of course the content of the buffer 4589** that the prior pointer references will have been modified. Other kinds 4590** of conversion are done in place when it is possible, but sometimes they 4591** are not possible and in those cases prior pointers are invalidated. 4592** 4593** The safest policy is to invoke these routines 4594** in one of the following ways: 4595** 4596** <ul> 4597** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4598** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4599** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4600** </ul> 4601** 4602** In other words, you should call sqlite3_column_text(), 4603** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4604** into the desired format, then invoke sqlite3_column_bytes() or 4605** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4606** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4607** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4608** with calls to sqlite3_column_bytes(). 4609** 4610** ^The pointers returned are valid until a type conversion occurs as 4611** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4612** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4613** and BLOBs is freed automatically. Do not pass the pointers returned 4614** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4615** [sqlite3_free()]. 4616** 4617** As long as the input parameters are correct, these routines will only 4618** fail if an out-of-memory error occurs during a format conversion. 4619** Only the following subset of interfaces are subject to out-of-memory 4620** errors: 4621** 4622** <ul> 4623** <li> sqlite3_column_blob() 4624** <li> sqlite3_column_text() 4625** <li> sqlite3_column_text16() 4626** <li> sqlite3_column_bytes() 4627** <li> sqlite3_column_bytes16() 4628** </ul> 4629** 4630** If an out-of-memory error occurs, then the return value from these 4631** routines is the same as if the column had contained an SQL NULL value. 4632** Valid SQL NULL returns can be distinguished from out-of-memory errors 4633** by invoking the [sqlite3_errcode()] immediately after the suspect 4634** return value is obtained and before any 4635** other SQLite interface is called on the same [database connection]. 4636*/ 4637const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4638double sqlite3_column_double(sqlite3_stmt*, int iCol); 4639int sqlite3_column_int(sqlite3_stmt*, int iCol); 4640sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4641const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4642const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4643sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4644int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4645int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4646int sqlite3_column_type(sqlite3_stmt*, int iCol); 4647 4648/* 4649** CAPI3REF: Destroy A Prepared Statement Object 4650** DESTRUCTOR: sqlite3_stmt 4651** 4652** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4653** ^If the most recent evaluation of the statement encountered no errors 4654** or if the statement is never been evaluated, then sqlite3_finalize() returns 4655** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4656** sqlite3_finalize(S) returns the appropriate [error code] or 4657** [extended error code]. 4658** 4659** ^The sqlite3_finalize(S) routine can be called at any point during 4660** the life cycle of [prepared statement] S: 4661** before statement S is ever evaluated, after 4662** one or more calls to [sqlite3_reset()], or after any call 4663** to [sqlite3_step()] regardless of whether or not the statement has 4664** completed execution. 4665** 4666** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4667** 4668** The application must finalize every [prepared statement] in order to avoid 4669** resource leaks. It is a grievous error for the application to try to use 4670** a prepared statement after it has been finalized. Any use of a prepared 4671** statement after it has been finalized can result in undefined and 4672** undesirable behavior such as segfaults and heap corruption. 4673*/ 4674int sqlite3_finalize(sqlite3_stmt *pStmt); 4675 4676/* 4677** CAPI3REF: Reset A Prepared Statement Object 4678** METHOD: sqlite3_stmt 4679** 4680** The sqlite3_reset() function is called to reset a [prepared statement] 4681** object back to its initial state, ready to be re-executed. 4682** ^Any SQL statement variables that had values bound to them using 4683** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4684** Use [sqlite3_clear_bindings()] to reset the bindings. 4685** 4686** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4687** back to the beginning of its program. 4688** 4689** ^If the most recent call to [sqlite3_step(S)] for the 4690** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4691** or if [sqlite3_step(S)] has never before been called on S, 4692** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4693** 4694** ^If the most recent call to [sqlite3_step(S)] for the 4695** [prepared statement] S indicated an error, then 4696** [sqlite3_reset(S)] returns an appropriate [error code]. 4697** 4698** ^The [sqlite3_reset(S)] interface does not change the values 4699** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4700*/ 4701int sqlite3_reset(sqlite3_stmt *pStmt); 4702 4703/* 4704** CAPI3REF: Create Or Redefine SQL Functions 4705** KEYWORDS: {function creation routines} 4706** KEYWORDS: {application-defined SQL function} 4707** KEYWORDS: {application-defined SQL functions} 4708** METHOD: sqlite3 4709** 4710** ^These functions (collectively known as "function creation routines") 4711** are used to add SQL functions or aggregates or to redefine the behavior 4712** of existing SQL functions or aggregates. The only differences between 4713** the three "sqlite3_create_function*" routines are the text encoding 4714** expected for the second parameter (the name of the function being 4715** created) and the presence or absence of a destructor callback for 4716** the application data pointer. Function sqlite3_create_window_function() 4717** is similar, but allows the user to supply the extra callback functions 4718** needed by [aggregate window functions]. 4719** 4720** ^The first parameter is the [database connection] to which the SQL 4721** function is to be added. ^If an application uses more than one database 4722** connection then application-defined SQL functions must be added 4723** to each database connection separately. 4724** 4725** ^The second parameter is the name of the SQL function to be created or 4726** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4727** representation, exclusive of the zero-terminator. ^Note that the name 4728** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4729** ^Any attempt to create a function with a longer name 4730** will result in [SQLITE_MISUSE] being returned. 4731** 4732** ^The third parameter (nArg) 4733** is the number of arguments that the SQL function or 4734** aggregate takes. ^If this parameter is -1, then the SQL function or 4735** aggregate may take any number of arguments between 0 and the limit 4736** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4737** parameter is less than -1 or greater than 127 then the behavior is 4738** undefined. 4739** 4740** ^The fourth parameter, eTextRep, specifies what 4741** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4742** its parameters. The application should set this parameter to 4743** [SQLITE_UTF16LE] if the function implementation invokes 4744** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4745** implementation invokes [sqlite3_value_text16be()] on an input, or 4746** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4747** otherwise. ^The same SQL function may be registered multiple times using 4748** different preferred text encodings, with different implementations for 4749** each encoding. 4750** ^When multiple implementations of the same function are available, SQLite 4751** will pick the one that involves the least amount of data conversion. 4752** 4753** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4754** to signal that the function will always return the same result given 4755** the same inputs within a single SQL statement. Most SQL functions are 4756** deterministic. The built-in [random()] SQL function is an example of a 4757** function that is not deterministic. The SQLite query planner is able to 4758** perform additional optimizations on deterministic functions, so use 4759** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4760** 4761** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4762** function can gain access to this pointer using [sqlite3_user_data()].)^ 4763** 4764** ^The sixth, seventh and eighth parameters passed to the three 4765** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are 4766** pointers to C-language functions that implement the SQL function or 4767** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4768** callback only; NULL pointers must be passed as the xStep and xFinal 4769** parameters. ^An aggregate SQL function requires an implementation of xStep 4770** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4771** SQL function or aggregate, pass NULL pointers for all three function 4772** callbacks. 4773** 4774** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue 4775** and xInverse) passed to sqlite3_create_window_function are pointers to 4776** C-language callbacks that implement the new function. xStep and xFinal 4777** must both be non-NULL. xValue and xInverse may either both be NULL, in 4778** which case a regular aggregate function is created, or must both be 4779** non-NULL, in which case the new function may be used as either an aggregate 4780** or aggregate window function. More details regarding the implementation 4781** of aggregate window functions are 4782** [user-defined window functions|available here]. 4783** 4784** ^(If the final parameter to sqlite3_create_function_v2() or 4785** sqlite3_create_window_function() is not NULL, then it is destructor for 4786** the application data pointer. The destructor is invoked when the function 4787** is deleted, either by being overloaded or when the database connection 4788** closes.)^ ^The destructor is also invoked if the call to 4789** sqlite3_create_function_v2() fails. ^When the destructor callback is 4790** invoked, it is passed a single argument which is a copy of the application 4791** data pointer which was the fifth parameter to sqlite3_create_function_v2(). 4792** 4793** ^It is permitted to register multiple implementations of the same 4794** functions with the same name but with either differing numbers of 4795** arguments or differing preferred text encodings. ^SQLite will use 4796** the implementation that most closely matches the way in which the 4797** SQL function is used. ^A function implementation with a non-negative 4798** nArg parameter is a better match than a function implementation with 4799** a negative nArg. ^A function where the preferred text encoding 4800** matches the database encoding is a better 4801** match than a function where the encoding is different. 4802** ^A function where the encoding difference is between UTF16le and UTF16be 4803** is a closer match than a function where the encoding difference is 4804** between UTF8 and UTF16. 4805** 4806** ^Built-in functions may be overloaded by new application-defined functions. 4807** 4808** ^An application-defined function is permitted to call other 4809** SQLite interfaces. However, such calls must not 4810** close the database connection nor finalize or reset the prepared 4811** statement in which the function is running. 4812*/ 4813int sqlite3_create_function( 4814 sqlite3 *db, 4815 const char *zFunctionName, 4816 int nArg, 4817 int eTextRep, 4818 void *pApp, 4819 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4820 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4821 void (*xFinal)(sqlite3_context*) 4822); 4823int sqlite3_create_function16( 4824 sqlite3 *db, 4825 const void *zFunctionName, 4826 int nArg, 4827 int eTextRep, 4828 void *pApp, 4829 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4830 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4831 void (*xFinal)(sqlite3_context*) 4832); 4833int sqlite3_create_function_v2( 4834 sqlite3 *db, 4835 const char *zFunctionName, 4836 int nArg, 4837 int eTextRep, 4838 void *pApp, 4839 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4840 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4841 void (*xFinal)(sqlite3_context*), 4842 void(*xDestroy)(void*) 4843); 4844int sqlite3_create_window_function( 4845 sqlite3 *db, 4846 const char *zFunctionName, 4847 int nArg, 4848 int eTextRep, 4849 void *pApp, 4850 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4851 void (*xFinal)(sqlite3_context*), 4852 void (*xValue)(sqlite3_context*), 4853 void (*xInverse)(sqlite3_context*,int,sqlite3_value**), 4854 void(*xDestroy)(void*) 4855); 4856 4857/* 4858** CAPI3REF: Text Encodings 4859** 4860** These constant define integer codes that represent the various 4861** text encodings supported by SQLite. 4862*/ 4863#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4864#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4865#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4866#define SQLITE_UTF16 4 /* Use native byte order */ 4867#define SQLITE_ANY 5 /* Deprecated */ 4868#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4869 4870/* 4871** CAPI3REF: Function Flags 4872** 4873** These constants may be ORed together with the 4874** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4875** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4876** [sqlite3_create_function_v2()]. 4877*/ 4878#define SQLITE_DETERMINISTIC 0x800 4879 4880/* 4881** CAPI3REF: Deprecated Functions 4882** DEPRECATED 4883** 4884** These functions are [deprecated]. In order to maintain 4885** backwards compatibility with older code, these functions continue 4886** to be supported. However, new applications should avoid 4887** the use of these functions. To encourage programmers to avoid 4888** these functions, we will not explain what they do. 4889*/ 4890#ifndef SQLITE_OMIT_DEPRECATED 4891SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4892SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4893SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4894SQLITE_DEPRECATED int sqlite3_global_recover(void); 4895SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4896SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4897 void*,sqlite3_int64); 4898#endif 4899 4900/* 4901** CAPI3REF: Obtaining SQL Values 4902** METHOD: sqlite3_value 4903** 4904** <b>Summary:</b> 4905** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4906** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 4907** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 4908** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 4909** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 4910** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 4911** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 4912** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 4913** the native byteorder 4914** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 4915** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 4916** <tr><td> <td> <td> 4917** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 4918** or a UTF-8 TEXT in bytes 4919** <tr><td><b>sqlite3_value_bytes16 </b> 4920** <td>→ <td>Size of UTF-16 4921** TEXT in bytes 4922** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 4923** datatype of the value 4924** <tr><td><b>sqlite3_value_numeric_type </b> 4925** <td>→ <td>Best numeric datatype of the value 4926** <tr><td><b>sqlite3_value_nochange </b> 4927** <td>→ <td>True if the column is unchanged in an UPDATE 4928** against a virtual table. 4929** </table></blockquote> 4930** 4931** <b>Details:</b> 4932** 4933** These routines extract type, size, and content information from 4934** [protected sqlite3_value] objects. Protected sqlite3_value objects 4935** are used to pass parameter information into implementation of 4936** [application-defined SQL functions] and [virtual tables]. 4937** 4938** These routines work only with [protected sqlite3_value] objects. 4939** Any attempt to use these routines on an [unprotected sqlite3_value] 4940** is not threadsafe. 4941** 4942** ^These routines work just like the corresponding [column access functions] 4943** except that these routines take a single [protected sqlite3_value] object 4944** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4945** 4946** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4947** in the native byte-order of the host machine. ^The 4948** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4949** extract UTF-16 strings as big-endian and little-endian respectively. 4950** 4951** ^If [sqlite3_value] object V was initialized 4952** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 4953** and if X and Y are strings that compare equal according to strcmp(X,Y), 4954** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 4955** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 4956** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 4957** 4958** ^(The sqlite3_value_type(V) interface returns the 4959** [SQLITE_INTEGER | datatype code] for the initial datatype of the 4960** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 4961** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 4962** Other interfaces might change the datatype for an sqlite3_value object. 4963** For example, if the datatype is initially SQLITE_INTEGER and 4964** sqlite3_value_text(V) is called to extract a text value for that 4965** integer, then subsequent calls to sqlite3_value_type(V) might return 4966** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 4967** occurs is undefined and may change from one release of SQLite to the next. 4968** 4969** ^(The sqlite3_value_numeric_type() interface attempts to apply 4970** numeric affinity to the value. This means that an attempt is 4971** made to convert the value to an integer or floating point. If 4972** such a conversion is possible without loss of information (in other 4973** words, if the value is a string that looks like a number) 4974** then the conversion is performed. Otherwise no conversion occurs. 4975** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4976** 4977** ^Within the [xUpdate] method of a [virtual table], the 4978** sqlite3_value_nochange(X) interface returns true if and only if 4979** the column corresponding to X is unchanged by the UPDATE operation 4980** that the xUpdate method call was invoked to implement and if 4981** and the prior [xColumn] method call that was invoked to extracted 4982** the value for that column returned without setting a result (probably 4983** because it queried [sqlite3_vtab_nochange()] and found that the column 4984** was unchanging). ^Within an [xUpdate] method, any value for which 4985** sqlite3_value_nochange(X) is true will in all other respects appear 4986** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other 4987** than within an [xUpdate] method call for an UPDATE statement, then 4988** the return value is arbitrary and meaningless. 4989** 4990** Please pay particular attention to the fact that the pointer returned 4991** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4992** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4993** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4994** or [sqlite3_value_text16()]. 4995** 4996** These routines must be called from the same thread as 4997** the SQL function that supplied the [sqlite3_value*] parameters. 4998** 4999** As long as the input parameter is correct, these routines can only 5000** fail if an out-of-memory error occurs during a format conversion. 5001** Only the following subset of interfaces are subject to out-of-memory 5002** errors: 5003** 5004** <ul> 5005** <li> sqlite3_value_blob() 5006** <li> sqlite3_value_text() 5007** <li> sqlite3_value_text16() 5008** <li> sqlite3_value_text16le() 5009** <li> sqlite3_value_text16be() 5010** <li> sqlite3_value_bytes() 5011** <li> sqlite3_value_bytes16() 5012** </ul> 5013** 5014** If an out-of-memory error occurs, then the return value from these 5015** routines is the same as if the column had contained an SQL NULL value. 5016** Valid SQL NULL returns can be distinguished from out-of-memory errors 5017** by invoking the [sqlite3_errcode()] immediately after the suspect 5018** return value is obtained and before any 5019** other SQLite interface is called on the same [database connection]. 5020*/ 5021const void *sqlite3_value_blob(sqlite3_value*); 5022double sqlite3_value_double(sqlite3_value*); 5023int sqlite3_value_int(sqlite3_value*); 5024sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 5025void *sqlite3_value_pointer(sqlite3_value*, const char*); 5026const unsigned char *sqlite3_value_text(sqlite3_value*); 5027const void *sqlite3_value_text16(sqlite3_value*); 5028const void *sqlite3_value_text16le(sqlite3_value*); 5029const void *sqlite3_value_text16be(sqlite3_value*); 5030int sqlite3_value_bytes(sqlite3_value*); 5031int sqlite3_value_bytes16(sqlite3_value*); 5032int sqlite3_value_type(sqlite3_value*); 5033int sqlite3_value_numeric_type(sqlite3_value*); 5034int sqlite3_value_nochange(sqlite3_value*); 5035 5036/* 5037** CAPI3REF: Finding The Subtype Of SQL Values 5038** METHOD: sqlite3_value 5039** 5040** The sqlite3_value_subtype(V) function returns the subtype for 5041** an [application-defined SQL function] argument V. The subtype 5042** information can be used to pass a limited amount of context from 5043** one SQL function to another. Use the [sqlite3_result_subtype()] 5044** routine to set the subtype for the return value of an SQL function. 5045*/ 5046unsigned int sqlite3_value_subtype(sqlite3_value*); 5047 5048/* 5049** CAPI3REF: Copy And Free SQL Values 5050** METHOD: sqlite3_value 5051** 5052** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 5053** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 5054** is a [protected sqlite3_value] object even if the input is not. 5055** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 5056** memory allocation fails. 5057** 5058** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 5059** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 5060** then sqlite3_value_free(V) is a harmless no-op. 5061*/ 5062sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 5063void sqlite3_value_free(sqlite3_value*); 5064 5065/* 5066** CAPI3REF: Obtain Aggregate Function Context 5067** METHOD: sqlite3_context 5068** 5069** Implementations of aggregate SQL functions use this 5070** routine to allocate memory for storing their state. 5071** 5072** ^The first time the sqlite3_aggregate_context(C,N) routine is called 5073** for a particular aggregate function, SQLite 5074** allocates N of memory, zeroes out that memory, and returns a pointer 5075** to the new memory. ^On second and subsequent calls to 5076** sqlite3_aggregate_context() for the same aggregate function instance, 5077** the same buffer is returned. Sqlite3_aggregate_context() is normally 5078** called once for each invocation of the xStep callback and then one 5079** last time when the xFinal callback is invoked. ^(When no rows match 5080** an aggregate query, the xStep() callback of the aggregate function 5081** implementation is never called and xFinal() is called exactly once. 5082** In those cases, sqlite3_aggregate_context() might be called for the 5083** first time from within xFinal().)^ 5084** 5085** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 5086** when first called if N is less than or equal to zero or if a memory 5087** allocate error occurs. 5088** 5089** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 5090** determined by the N parameter on first successful call. Changing the 5091** value of N in subsequent call to sqlite3_aggregate_context() within 5092** the same aggregate function instance will not resize the memory 5093** allocation.)^ Within the xFinal callback, it is customary to set 5094** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 5095** pointless memory allocations occur. 5096** 5097** ^SQLite automatically frees the memory allocated by 5098** sqlite3_aggregate_context() when the aggregate query concludes. 5099** 5100** The first parameter must be a copy of the 5101** [sqlite3_context | SQL function context] that is the first parameter 5102** to the xStep or xFinal callback routine that implements the aggregate 5103** function. 5104** 5105** This routine must be called from the same thread in which 5106** the aggregate SQL function is running. 5107*/ 5108void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 5109 5110/* 5111** CAPI3REF: User Data For Functions 5112** METHOD: sqlite3_context 5113** 5114** ^The sqlite3_user_data() interface returns a copy of 5115** the pointer that was the pUserData parameter (the 5th parameter) 5116** of the [sqlite3_create_function()] 5117** and [sqlite3_create_function16()] routines that originally 5118** registered the application defined function. 5119** 5120** This routine must be called from the same thread in which 5121** the application-defined function is running. 5122*/ 5123void *sqlite3_user_data(sqlite3_context*); 5124 5125/* 5126** CAPI3REF: Database Connection For Functions 5127** METHOD: sqlite3_context 5128** 5129** ^The sqlite3_context_db_handle() interface returns a copy of 5130** the pointer to the [database connection] (the 1st parameter) 5131** of the [sqlite3_create_function()] 5132** and [sqlite3_create_function16()] routines that originally 5133** registered the application defined function. 5134*/ 5135sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 5136 5137/* 5138** CAPI3REF: Function Auxiliary Data 5139** METHOD: sqlite3_context 5140** 5141** These functions may be used by (non-aggregate) SQL functions to 5142** associate metadata with argument values. If the same value is passed to 5143** multiple invocations of the same SQL function during query execution, under 5144** some circumstances the associated metadata may be preserved. An example 5145** of where this might be useful is in a regular-expression matching 5146** function. The compiled version of the regular expression can be stored as 5147** metadata associated with the pattern string. 5148** Then as long as the pattern string remains the same, 5149** the compiled regular expression can be reused on multiple 5150** invocations of the same function. 5151** 5152** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 5153** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 5154** value to the application-defined function. ^N is zero for the left-most 5155** function argument. ^If there is no metadata 5156** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 5157** returns a NULL pointer. 5158** 5159** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 5160** argument of the application-defined function. ^Subsequent 5161** calls to sqlite3_get_auxdata(C,N) return P from the most recent 5162** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 5163** NULL if the metadata has been discarded. 5164** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 5165** SQLite will invoke the destructor function X with parameter P exactly 5166** once, when the metadata is discarded. 5167** SQLite is free to discard the metadata at any time, including: <ul> 5168** <li> ^(when the corresponding function parameter changes)^, or 5169** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 5170** SQL statement)^, or 5171** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 5172** parameter)^, or 5173** <li> ^(during the original sqlite3_set_auxdata() call when a memory 5174** allocation error occurs.)^ </ul> 5175** 5176** Note the last bullet in particular. The destructor X in 5177** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 5178** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 5179** should be called near the end of the function implementation and the 5180** function implementation should not make any use of P after 5181** sqlite3_set_auxdata() has been called. 5182** 5183** ^(In practice, metadata is preserved between function calls for 5184** function parameters that are compile-time constants, including literal 5185** values and [parameters] and expressions composed from the same.)^ 5186** 5187** The value of the N parameter to these interfaces should be non-negative. 5188** Future enhancements may make use of negative N values to define new 5189** kinds of function caching behavior. 5190** 5191** These routines must be called from the same thread in which 5192** the SQL function is running. 5193*/ 5194void *sqlite3_get_auxdata(sqlite3_context*, int N); 5195void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5196 5197 5198/* 5199** CAPI3REF: Constants Defining Special Destructor Behavior 5200** 5201** These are special values for the destructor that is passed in as the 5202** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5203** argument is SQLITE_STATIC, it means that the content pointer is constant 5204** and will never change. It does not need to be destroyed. ^The 5205** SQLITE_TRANSIENT value means that the content will likely change in 5206** the near future and that SQLite should make its own private copy of 5207** the content before returning. 5208** 5209** The typedef is necessary to work around problems in certain 5210** C++ compilers. 5211*/ 5212typedef void (*sqlite3_destructor_type)(void*); 5213#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5214#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5215 5216/* 5217** CAPI3REF: Setting The Result Of An SQL Function 5218** METHOD: sqlite3_context 5219** 5220** These routines are used by the xFunc or xFinal callbacks that 5221** implement SQL functions and aggregates. See 5222** [sqlite3_create_function()] and [sqlite3_create_function16()] 5223** for additional information. 5224** 5225** These functions work very much like the [parameter binding] family of 5226** functions used to bind values to host parameters in prepared statements. 5227** Refer to the [SQL parameter] documentation for additional information. 5228** 5229** ^The sqlite3_result_blob() interface sets the result from 5230** an application-defined function to be the BLOB whose content is pointed 5231** to by the second parameter and which is N bytes long where N is the 5232** third parameter. 5233** 5234** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5235** interfaces set the result of the application-defined function to be 5236** a BLOB containing all zero bytes and N bytes in size. 5237** 5238** ^The sqlite3_result_double() interface sets the result from 5239** an application-defined function to be a floating point value specified 5240** by its 2nd argument. 5241** 5242** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5243** cause the implemented SQL function to throw an exception. 5244** ^SQLite uses the string pointed to by the 5245** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5246** as the text of an error message. ^SQLite interprets the error 5247** message string from sqlite3_result_error() as UTF-8. ^SQLite 5248** interprets the string from sqlite3_result_error16() as UTF-16 in native 5249** byte order. ^If the third parameter to sqlite3_result_error() 5250** or sqlite3_result_error16() is negative then SQLite takes as the error 5251** message all text up through the first zero character. 5252** ^If the third parameter to sqlite3_result_error() or 5253** sqlite3_result_error16() is non-negative then SQLite takes that many 5254** bytes (not characters) from the 2nd parameter as the error message. 5255** ^The sqlite3_result_error() and sqlite3_result_error16() 5256** routines make a private copy of the error message text before 5257** they return. Hence, the calling function can deallocate or 5258** modify the text after they return without harm. 5259** ^The sqlite3_result_error_code() function changes the error code 5260** returned by SQLite as a result of an error in a function. ^By default, 5261** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5262** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5263** 5264** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5265** error indicating that a string or BLOB is too long to represent. 5266** 5267** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5268** error indicating that a memory allocation failed. 5269** 5270** ^The sqlite3_result_int() interface sets the return value 5271** of the application-defined function to be the 32-bit signed integer 5272** value given in the 2nd argument. 5273** ^The sqlite3_result_int64() interface sets the return value 5274** of the application-defined function to be the 64-bit signed integer 5275** value given in the 2nd argument. 5276** 5277** ^The sqlite3_result_null() interface sets the return value 5278** of the application-defined function to be NULL. 5279** 5280** ^The sqlite3_result_text(), sqlite3_result_text16(), 5281** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5282** set the return value of the application-defined function to be 5283** a text string which is represented as UTF-8, UTF-16 native byte order, 5284** UTF-16 little endian, or UTF-16 big endian, respectively. 5285** ^The sqlite3_result_text64() interface sets the return value of an 5286** application-defined function to be a text string in an encoding 5287** specified by the fifth (and last) parameter, which must be one 5288** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5289** ^SQLite takes the text result from the application from 5290** the 2nd parameter of the sqlite3_result_text* interfaces. 5291** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5292** is negative, then SQLite takes result text from the 2nd parameter 5293** through the first zero character. 5294** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5295** is non-negative, then as many bytes (not characters) of the text 5296** pointed to by the 2nd parameter are taken as the application-defined 5297** function result. If the 3rd parameter is non-negative, then it 5298** must be the byte offset into the string where the NUL terminator would 5299** appear if the string where NUL terminated. If any NUL characters occur 5300** in the string at a byte offset that is less than the value of the 3rd 5301** parameter, then the resulting string will contain embedded NULs and the 5302** result of expressions operating on strings with embedded NULs is undefined. 5303** ^If the 4th parameter to the sqlite3_result_text* interfaces 5304** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5305** function as the destructor on the text or BLOB result when it has 5306** finished using that result. 5307** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5308** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5309** assumes that the text or BLOB result is in constant space and does not 5310** copy the content of the parameter nor call a destructor on the content 5311** when it has finished using that result. 5312** ^If the 4th parameter to the sqlite3_result_text* interfaces 5313** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5314** then SQLite makes a copy of the result into space obtained 5315** from [sqlite3_malloc()] before it returns. 5316** 5317** ^The sqlite3_result_value() interface sets the result of 5318** the application-defined function to be a copy of the 5319** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5320** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5321** so that the [sqlite3_value] specified in the parameter may change or 5322** be deallocated after sqlite3_result_value() returns without harm. 5323** ^A [protected sqlite3_value] object may always be used where an 5324** [unprotected sqlite3_value] object is required, so either 5325** kind of [sqlite3_value] object can be used with this interface. 5326** 5327** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5328** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5329** also associates the host-language pointer P or type T with that 5330** NULL value such that the pointer can be retrieved within an 5331** [application-defined SQL function] using [sqlite3_value_pointer()]. 5332** ^If the D parameter is not NULL, then it is a pointer to a destructor 5333** for the P parameter. ^SQLite invokes D with P as its only argument 5334** when SQLite is finished with P. The T parameter should be a static 5335** string and preferably a string literal. The sqlite3_result_pointer() 5336** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5337** 5338** If these routines are called from within the different thread 5339** than the one containing the application-defined function that received 5340** the [sqlite3_context] pointer, the results are undefined. 5341*/ 5342void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5343void sqlite3_result_blob64(sqlite3_context*,const void*, 5344 sqlite3_uint64,void(*)(void*)); 5345void sqlite3_result_double(sqlite3_context*, double); 5346void sqlite3_result_error(sqlite3_context*, const char*, int); 5347void sqlite3_result_error16(sqlite3_context*, const void*, int); 5348void sqlite3_result_error_toobig(sqlite3_context*); 5349void sqlite3_result_error_nomem(sqlite3_context*); 5350void sqlite3_result_error_code(sqlite3_context*, int); 5351void sqlite3_result_int(sqlite3_context*, int); 5352void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5353void sqlite3_result_null(sqlite3_context*); 5354void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5355void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5356 void(*)(void*), unsigned char encoding); 5357void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5358void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5359void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5360void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5361void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5362void sqlite3_result_zeroblob(sqlite3_context*, int n); 5363int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5364 5365 5366/* 5367** CAPI3REF: Setting The Subtype Of An SQL Function 5368** METHOD: sqlite3_context 5369** 5370** The sqlite3_result_subtype(C,T) function causes the subtype of 5371** the result from the [application-defined SQL function] with 5372** [sqlite3_context] C to be the value T. Only the lower 8 bits 5373** of the subtype T are preserved in current versions of SQLite; 5374** higher order bits are discarded. 5375** The number of subtype bytes preserved by SQLite might increase 5376** in future releases of SQLite. 5377*/ 5378void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5379 5380/* 5381** CAPI3REF: Define New Collating Sequences 5382** METHOD: sqlite3 5383** 5384** ^These functions add, remove, or modify a [collation] associated 5385** with the [database connection] specified as the first argument. 5386** 5387** ^The name of the collation is a UTF-8 string 5388** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5389** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5390** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5391** considered to be the same name. 5392** 5393** ^(The third argument (eTextRep) must be one of the constants: 5394** <ul> 5395** <li> [SQLITE_UTF8], 5396** <li> [SQLITE_UTF16LE], 5397** <li> [SQLITE_UTF16BE], 5398** <li> [SQLITE_UTF16], or 5399** <li> [SQLITE_UTF16_ALIGNED]. 5400** </ul>)^ 5401** ^The eTextRep argument determines the encoding of strings passed 5402** to the collating function callback, xCallback. 5403** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5404** force strings to be UTF16 with native byte order. 5405** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5406** on an even byte address. 5407** 5408** ^The fourth argument, pArg, is an application data pointer that is passed 5409** through as the first argument to the collating function callback. 5410** 5411** ^The fifth argument, xCallback, is a pointer to the collating function. 5412** ^Multiple collating functions can be registered using the same name but 5413** with different eTextRep parameters and SQLite will use whichever 5414** function requires the least amount of data transformation. 5415** ^If the xCallback argument is NULL then the collating function is 5416** deleted. ^When all collating functions having the same name are deleted, 5417** that collation is no longer usable. 5418** 5419** ^The collating function callback is invoked with a copy of the pArg 5420** application data pointer and with two strings in the encoding specified 5421** by the eTextRep argument. The collating function must return an 5422** integer that is negative, zero, or positive 5423** if the first string is less than, equal to, or greater than the second, 5424** respectively. A collating function must always return the same answer 5425** given the same inputs. If two or more collating functions are registered 5426** to the same collation name (using different eTextRep values) then all 5427** must give an equivalent answer when invoked with equivalent strings. 5428** The collating function must obey the following properties for all 5429** strings A, B, and C: 5430** 5431** <ol> 5432** <li> If A==B then B==A. 5433** <li> If A==B and B==C then A==C. 5434** <li> If A<B THEN B>A. 5435** <li> If A<B and B<C then A<C. 5436** </ol> 5437** 5438** If a collating function fails any of the above constraints and that 5439** collating function is registered and used, then the behavior of SQLite 5440** is undefined. 5441** 5442** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5443** with the addition that the xDestroy callback is invoked on pArg when 5444** the collating function is deleted. 5445** ^Collating functions are deleted when they are overridden by later 5446** calls to the collation creation functions or when the 5447** [database connection] is closed using [sqlite3_close()]. 5448** 5449** ^The xDestroy callback is <u>not</u> called if the 5450** sqlite3_create_collation_v2() function fails. Applications that invoke 5451** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5452** check the return code and dispose of the application data pointer 5453** themselves rather than expecting SQLite to deal with it for them. 5454** This is different from every other SQLite interface. The inconsistency 5455** is unfortunate but cannot be changed without breaking backwards 5456** compatibility. 5457** 5458** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5459*/ 5460int sqlite3_create_collation( 5461 sqlite3*, 5462 const char *zName, 5463 int eTextRep, 5464 void *pArg, 5465 int(*xCompare)(void*,int,const void*,int,const void*) 5466); 5467int sqlite3_create_collation_v2( 5468 sqlite3*, 5469 const char *zName, 5470 int eTextRep, 5471 void *pArg, 5472 int(*xCompare)(void*,int,const void*,int,const void*), 5473 void(*xDestroy)(void*) 5474); 5475int sqlite3_create_collation16( 5476 sqlite3*, 5477 const void *zName, 5478 int eTextRep, 5479 void *pArg, 5480 int(*xCompare)(void*,int,const void*,int,const void*) 5481); 5482 5483/* 5484** CAPI3REF: Collation Needed Callbacks 5485** METHOD: sqlite3 5486** 5487** ^To avoid having to register all collation sequences before a database 5488** can be used, a single callback function may be registered with the 5489** [database connection] to be invoked whenever an undefined collation 5490** sequence is required. 5491** 5492** ^If the function is registered using the sqlite3_collation_needed() API, 5493** then it is passed the names of undefined collation sequences as strings 5494** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5495** the names are passed as UTF-16 in machine native byte order. 5496** ^A call to either function replaces the existing collation-needed callback. 5497** 5498** ^(When the callback is invoked, the first argument passed is a copy 5499** of the second argument to sqlite3_collation_needed() or 5500** sqlite3_collation_needed16(). The second argument is the database 5501** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5502** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5503** sequence function required. The fourth parameter is the name of the 5504** required collation sequence.)^ 5505** 5506** The callback function should register the desired collation using 5507** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5508** [sqlite3_create_collation_v2()]. 5509*/ 5510int sqlite3_collation_needed( 5511 sqlite3*, 5512 void*, 5513 void(*)(void*,sqlite3*,int eTextRep,const char*) 5514); 5515int sqlite3_collation_needed16( 5516 sqlite3*, 5517 void*, 5518 void(*)(void*,sqlite3*,int eTextRep,const void*) 5519); 5520 5521#ifdef SQLITE_HAS_CODEC 5522/* 5523** Specify the key for an encrypted database. This routine should be 5524** called right after sqlite3_open(). 5525** 5526** The code to implement this API is not available in the public release 5527** of SQLite. 5528*/ 5529int sqlite3_key( 5530 sqlite3 *db, /* Database to be rekeyed */ 5531 const void *pKey, int nKey /* The key */ 5532); 5533int sqlite3_key_v2( 5534 sqlite3 *db, /* Database to be rekeyed */ 5535 const char *zDbName, /* Name of the database */ 5536 const void *pKey, int nKey /* The key */ 5537); 5538 5539/* 5540** Change the key on an open database. If the current database is not 5541** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 5542** database is decrypted. 5543** 5544** The code to implement this API is not available in the public release 5545** of SQLite. 5546*/ 5547int sqlite3_rekey( 5548 sqlite3 *db, /* Database to be rekeyed */ 5549 const void *pKey, int nKey /* The new key */ 5550); 5551int sqlite3_rekey_v2( 5552 sqlite3 *db, /* Database to be rekeyed */ 5553 const char *zDbName, /* Name of the database */ 5554 const void *pKey, int nKey /* The new key */ 5555); 5556 5557/* 5558** Specify the activation key for a SEE database. Unless 5559** activated, none of the SEE routines will work. 5560*/ 5561void sqlite3_activate_see( 5562 const char *zPassPhrase /* Activation phrase */ 5563); 5564#endif 5565 5566#ifdef SQLITE_ENABLE_CEROD 5567/* 5568** Specify the activation key for a CEROD database. Unless 5569** activated, none of the CEROD routines will work. 5570*/ 5571void sqlite3_activate_cerod( 5572 const char *zPassPhrase /* Activation phrase */ 5573); 5574#endif 5575 5576/* 5577** CAPI3REF: Suspend Execution For A Short Time 5578** 5579** The sqlite3_sleep() function causes the current thread to suspend execution 5580** for at least a number of milliseconds specified in its parameter. 5581** 5582** If the operating system does not support sleep requests with 5583** millisecond time resolution, then the time will be rounded up to 5584** the nearest second. The number of milliseconds of sleep actually 5585** requested from the operating system is returned. 5586** 5587** ^SQLite implements this interface by calling the xSleep() 5588** method of the default [sqlite3_vfs] object. If the xSleep() method 5589** of the default VFS is not implemented correctly, or not implemented at 5590** all, then the behavior of sqlite3_sleep() may deviate from the description 5591** in the previous paragraphs. 5592*/ 5593int sqlite3_sleep(int); 5594 5595/* 5596** CAPI3REF: Name Of The Folder Holding Temporary Files 5597** 5598** ^(If this global variable is made to point to a string which is 5599** the name of a folder (a.k.a. directory), then all temporary files 5600** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5601** will be placed in that directory.)^ ^If this variable 5602** is a NULL pointer, then SQLite performs a search for an appropriate 5603** temporary file directory. 5604** 5605** Applications are strongly discouraged from using this global variable. 5606** It is required to set a temporary folder on Windows Runtime (WinRT). 5607** But for all other platforms, it is highly recommended that applications 5608** neither read nor write this variable. This global variable is a relic 5609** that exists for backwards compatibility of legacy applications and should 5610** be avoided in new projects. 5611** 5612** It is not safe to read or modify this variable in more than one 5613** thread at a time. It is not safe to read or modify this variable 5614** if a [database connection] is being used at the same time in a separate 5615** thread. 5616** It is intended that this variable be set once 5617** as part of process initialization and before any SQLite interface 5618** routines have been called and that this variable remain unchanged 5619** thereafter. 5620** 5621** ^The [temp_store_directory pragma] may modify this variable and cause 5622** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5623** the [temp_store_directory pragma] always assumes that any string 5624** that this variable points to is held in memory obtained from 5625** [sqlite3_malloc] and the pragma may attempt to free that memory 5626** using [sqlite3_free]. 5627** Hence, if this variable is modified directly, either it should be 5628** made NULL or made to point to memory obtained from [sqlite3_malloc] 5629** or else the use of the [temp_store_directory pragma] should be avoided. 5630** Except when requested by the [temp_store_directory pragma], SQLite 5631** does not free the memory that sqlite3_temp_directory points to. If 5632** the application wants that memory to be freed, it must do 5633** so itself, taking care to only do so after all [database connection] 5634** objects have been destroyed. 5635** 5636** <b>Note to Windows Runtime users:</b> The temporary directory must be set 5637** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 5638** features that require the use of temporary files may fail. Here is an 5639** example of how to do this using C++ with the Windows Runtime: 5640** 5641** <blockquote><pre> 5642** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 5643** TemporaryFolder->Path->Data(); 5644** char zPathBuf[MAX_PATH + 1]; 5645** memset(zPathBuf, 0, sizeof(zPathBuf)); 5646** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 5647** NULL, NULL); 5648** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 5649** </pre></blockquote> 5650*/ 5651SQLITE_EXTERN char *sqlite3_temp_directory; 5652 5653/* 5654** CAPI3REF: Name Of The Folder Holding Database Files 5655** 5656** ^(If this global variable is made to point to a string which is 5657** the name of a folder (a.k.a. directory), then all database files 5658** specified with a relative pathname and created or accessed by 5659** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 5660** to be relative to that directory.)^ ^If this variable is a NULL 5661** pointer, then SQLite assumes that all database files specified 5662** with a relative pathname are relative to the current directory 5663** for the process. Only the windows VFS makes use of this global 5664** variable; it is ignored by the unix VFS. 5665** 5666** Changing the value of this variable while a database connection is 5667** open can result in a corrupt database. 5668** 5669** It is not safe to read or modify this variable in more than one 5670** thread at a time. It is not safe to read or modify this variable 5671** if a [database connection] is being used at the same time in a separate 5672** thread. 5673** It is intended that this variable be set once 5674** as part of process initialization and before any SQLite interface 5675** routines have been called and that this variable remain unchanged 5676** thereafter. 5677** 5678** ^The [data_store_directory pragma] may modify this variable and cause 5679** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5680** the [data_store_directory pragma] always assumes that any string 5681** that this variable points to is held in memory obtained from 5682** [sqlite3_malloc] and the pragma may attempt to free that memory 5683** using [sqlite3_free]. 5684** Hence, if this variable is modified directly, either it should be 5685** made NULL or made to point to memory obtained from [sqlite3_malloc] 5686** or else the use of the [data_store_directory pragma] should be avoided. 5687*/ 5688SQLITE_EXTERN char *sqlite3_data_directory; 5689 5690/* 5691** CAPI3REF: Win32 Specific Interface 5692** 5693** These interfaces are available only on Windows. The 5694** [sqlite3_win32_set_directory] interface is used to set the value associated 5695** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to 5696** zValue, depending on the value of the type parameter. The zValue parameter 5697** should be NULL to cause the previous value to be freed via [sqlite3_free]; 5698** a non-NULL value will be copied into memory obtained from [sqlite3_malloc] 5699** prior to being used. The [sqlite3_win32_set_directory] interface returns 5700** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported, 5701** or [SQLITE_NOMEM] if memory could not be allocated. The value of the 5702** [sqlite3_data_directory] variable is intended to act as a replacement for 5703** the current directory on the sub-platforms of Win32 where that concept is 5704** not present, e.g. WinRT and UWP. The [sqlite3_win32_set_directory8] and 5705** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the 5706** sqlite3_win32_set_directory interface except the string parameter must be 5707** UTF-8 or UTF-16, respectively. 5708*/ 5709int sqlite3_win32_set_directory( 5710 unsigned long type, /* Identifier for directory being set or reset */ 5711 void *zValue /* New value for directory being set or reset */ 5712); 5713int sqlite3_win32_set_directory8(unsigned long type, const char *zValue); 5714int sqlite3_win32_set_directory16(unsigned long type, const void *zValue); 5715 5716/* 5717** CAPI3REF: Win32 Directory Types 5718** 5719** These macros are only available on Windows. They define the allowed values 5720** for the type argument to the [sqlite3_win32_set_directory] interface. 5721*/ 5722#define SQLITE_WIN32_DATA_DIRECTORY_TYPE 1 5723#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE 2 5724 5725/* 5726** CAPI3REF: Test For Auto-Commit Mode 5727** KEYWORDS: {autocommit mode} 5728** METHOD: sqlite3 5729** 5730** ^The sqlite3_get_autocommit() interface returns non-zero or 5731** zero if the given database connection is or is not in autocommit mode, 5732** respectively. ^Autocommit mode is on by default. 5733** ^Autocommit mode is disabled by a [BEGIN] statement. 5734** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5735** 5736** If certain kinds of errors occur on a statement within a multi-statement 5737** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5738** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5739** transaction might be rolled back automatically. The only way to 5740** find out whether SQLite automatically rolled back the transaction after 5741** an error is to use this function. 5742** 5743** If another thread changes the autocommit status of the database 5744** connection while this routine is running, then the return value 5745** is undefined. 5746*/ 5747int sqlite3_get_autocommit(sqlite3*); 5748 5749/* 5750** CAPI3REF: Find The Database Handle Of A Prepared Statement 5751** METHOD: sqlite3_stmt 5752** 5753** ^The sqlite3_db_handle interface returns the [database connection] handle 5754** to which a [prepared statement] belongs. ^The [database connection] 5755** returned by sqlite3_db_handle is the same [database connection] 5756** that was the first argument 5757** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5758** create the statement in the first place. 5759*/ 5760sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5761 5762/* 5763** CAPI3REF: Return The Filename For A Database Connection 5764** METHOD: sqlite3 5765** 5766** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5767** associated with database N of connection D. ^The main database file 5768** has the name "main". If there is no attached database N on the database 5769** connection D, or if database N is a temporary or in-memory database, then 5770** a NULL pointer is returned. 5771** 5772** ^The filename returned by this function is the output of the 5773** xFullPathname method of the [VFS]. ^In other words, the filename 5774** will be an absolute pathname, even if the filename used 5775** to open the database originally was a URI or relative pathname. 5776*/ 5777const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5778 5779/* 5780** CAPI3REF: Determine if a database is read-only 5781** METHOD: sqlite3 5782** 5783** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5784** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5785** the name of a database on connection D. 5786*/ 5787int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5788 5789/* 5790** CAPI3REF: Find the next prepared statement 5791** METHOD: sqlite3 5792** 5793** ^This interface returns a pointer to the next [prepared statement] after 5794** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5795** then this interface returns a pointer to the first prepared statement 5796** associated with the database connection pDb. ^If no prepared statement 5797** satisfies the conditions of this routine, it returns NULL. 5798** 5799** The [database connection] pointer D in a call to 5800** [sqlite3_next_stmt(D,S)] must refer to an open database 5801** connection and in particular must not be a NULL pointer. 5802*/ 5803sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5804 5805/* 5806** CAPI3REF: Commit And Rollback Notification Callbacks 5807** METHOD: sqlite3 5808** 5809** ^The sqlite3_commit_hook() interface registers a callback 5810** function to be invoked whenever a transaction is [COMMIT | committed]. 5811** ^Any callback set by a previous call to sqlite3_commit_hook() 5812** for the same database connection is overridden. 5813** ^The sqlite3_rollback_hook() interface registers a callback 5814** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5815** ^Any callback set by a previous call to sqlite3_rollback_hook() 5816** for the same database connection is overridden. 5817** ^The pArg argument is passed through to the callback. 5818** ^If the callback on a commit hook function returns non-zero, 5819** then the commit is converted into a rollback. 5820** 5821** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5822** return the P argument from the previous call of the same function 5823** on the same [database connection] D, or NULL for 5824** the first call for each function on D. 5825** 5826** The commit and rollback hook callbacks are not reentrant. 5827** The callback implementation must not do anything that will modify 5828** the database connection that invoked the callback. Any actions 5829** to modify the database connection must be deferred until after the 5830** completion of the [sqlite3_step()] call that triggered the commit 5831** or rollback hook in the first place. 5832** Note that running any other SQL statements, including SELECT statements, 5833** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5834** the database connections for the meaning of "modify" in this paragraph. 5835** 5836** ^Registering a NULL function disables the callback. 5837** 5838** ^When the commit hook callback routine returns zero, the [COMMIT] 5839** operation is allowed to continue normally. ^If the commit hook 5840** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5841** ^The rollback hook is invoked on a rollback that results from a commit 5842** hook returning non-zero, just as it would be with any other rollback. 5843** 5844** ^For the purposes of this API, a transaction is said to have been 5845** rolled back if an explicit "ROLLBACK" statement is executed, or 5846** an error or constraint causes an implicit rollback to occur. 5847** ^The rollback callback is not invoked if a transaction is 5848** automatically rolled back because the database connection is closed. 5849** 5850** See also the [sqlite3_update_hook()] interface. 5851*/ 5852void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5853void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5854 5855/* 5856** CAPI3REF: Data Change Notification Callbacks 5857** METHOD: sqlite3 5858** 5859** ^The sqlite3_update_hook() interface registers a callback function 5860** with the [database connection] identified by the first argument 5861** to be invoked whenever a row is updated, inserted or deleted in 5862** a [rowid table]. 5863** ^Any callback set by a previous call to this function 5864** for the same database connection is overridden. 5865** 5866** ^The second argument is a pointer to the function to invoke when a 5867** row is updated, inserted or deleted in a rowid table. 5868** ^The first argument to the callback is a copy of the third argument 5869** to sqlite3_update_hook(). 5870** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5871** or [SQLITE_UPDATE], depending on the operation that caused the callback 5872** to be invoked. 5873** ^The third and fourth arguments to the callback contain pointers to the 5874** database and table name containing the affected row. 5875** ^The final callback parameter is the [rowid] of the row. 5876** ^In the case of an update, this is the [rowid] after the update takes place. 5877** 5878** ^(The update hook is not invoked when internal system tables are 5879** modified (i.e. sqlite_master and sqlite_sequence).)^ 5880** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5881** 5882** ^In the current implementation, the update hook 5883** is not invoked when conflicting rows are deleted because of an 5884** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5885** invoked when rows are deleted using the [truncate optimization]. 5886** The exceptions defined in this paragraph might change in a future 5887** release of SQLite. 5888** 5889** The update hook implementation must not do anything that will modify 5890** the database connection that invoked the update hook. Any actions 5891** to modify the database connection must be deferred until after the 5892** completion of the [sqlite3_step()] call that triggered the update hook. 5893** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5894** database connections for the meaning of "modify" in this paragraph. 5895** 5896** ^The sqlite3_update_hook(D,C,P) function 5897** returns the P argument from the previous call 5898** on the same [database connection] D, or NULL for 5899** the first call on D. 5900** 5901** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 5902** and [sqlite3_preupdate_hook()] interfaces. 5903*/ 5904void *sqlite3_update_hook( 5905 sqlite3*, 5906 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5907 void* 5908); 5909 5910/* 5911** CAPI3REF: Enable Or Disable Shared Pager Cache 5912** 5913** ^(This routine enables or disables the sharing of the database cache 5914** and schema data structures between [database connection | connections] 5915** to the same database. Sharing is enabled if the argument is true 5916** and disabled if the argument is false.)^ 5917** 5918** ^Cache sharing is enabled and disabled for an entire process. 5919** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 5920** In prior versions of SQLite, 5921** sharing was enabled or disabled for each thread separately. 5922** 5923** ^(The cache sharing mode set by this interface effects all subsequent 5924** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5925** Existing database connections continue use the sharing mode 5926** that was in effect at the time they were opened.)^ 5927** 5928** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5929** successfully. An [error code] is returned otherwise.)^ 5930** 5931** ^Shared cache is disabled by default. But this might change in 5932** future releases of SQLite. Applications that care about shared 5933** cache setting should set it explicitly. 5934** 5935** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5936** and will always return SQLITE_MISUSE. On those systems, 5937** shared cache mode should be enabled per-database connection via 5938** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5939** 5940** This interface is threadsafe on processors where writing a 5941** 32-bit integer is atomic. 5942** 5943** See Also: [SQLite Shared-Cache Mode] 5944*/ 5945int sqlite3_enable_shared_cache(int); 5946 5947/* 5948** CAPI3REF: Attempt To Free Heap Memory 5949** 5950** ^The sqlite3_release_memory() interface attempts to free N bytes 5951** of heap memory by deallocating non-essential memory allocations 5952** held by the database library. Memory used to cache database 5953** pages to improve performance is an example of non-essential memory. 5954** ^sqlite3_release_memory() returns the number of bytes actually freed, 5955** which might be more or less than the amount requested. 5956** ^The sqlite3_release_memory() routine is a no-op returning zero 5957** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5958** 5959** See also: [sqlite3_db_release_memory()] 5960*/ 5961int sqlite3_release_memory(int); 5962 5963/* 5964** CAPI3REF: Free Memory Used By A Database Connection 5965** METHOD: sqlite3 5966** 5967** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5968** memory as possible from database connection D. Unlike the 5969** [sqlite3_release_memory()] interface, this interface is in effect even 5970** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5971** omitted. 5972** 5973** See also: [sqlite3_release_memory()] 5974*/ 5975int sqlite3_db_release_memory(sqlite3*); 5976 5977/* 5978** CAPI3REF: Impose A Limit On Heap Size 5979** 5980** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5981** soft limit on the amount of heap memory that may be allocated by SQLite. 5982** ^SQLite strives to keep heap memory utilization below the soft heap 5983** limit by reducing the number of pages held in the page cache 5984** as heap memory usages approaches the limit. 5985** ^The soft heap limit is "soft" because even though SQLite strives to stay 5986** below the limit, it will exceed the limit rather than generate 5987** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5988** is advisory only. 5989** 5990** ^The return value from sqlite3_soft_heap_limit64() is the size of 5991** the soft heap limit prior to the call, or negative in the case of an 5992** error. ^If the argument N is negative 5993** then no change is made to the soft heap limit. Hence, the current 5994** size of the soft heap limit can be determined by invoking 5995** sqlite3_soft_heap_limit64() with a negative argument. 5996** 5997** ^If the argument N is zero then the soft heap limit is disabled. 5998** 5999** ^(The soft heap limit is not enforced in the current implementation 6000** if one or more of following conditions are true: 6001** 6002** <ul> 6003** <li> The soft heap limit is set to zero. 6004** <li> Memory accounting is disabled using a combination of the 6005** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 6006** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 6007** <li> An alternative page cache implementation is specified using 6008** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 6009** <li> The page cache allocates from its own memory pool supplied 6010** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 6011** from the heap. 6012** </ul>)^ 6013** 6014** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]), 6015** the soft heap limit is enforced 6016** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 6017** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 6018** the soft heap limit is enforced on every memory allocation. Without 6019** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 6020** when memory is allocated by the page cache. Testing suggests that because 6021** the page cache is the predominate memory user in SQLite, most 6022** applications will achieve adequate soft heap limit enforcement without 6023** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 6024** 6025** The circumstances under which SQLite will enforce the soft heap limit may 6026** changes in future releases of SQLite. 6027*/ 6028sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 6029 6030/* 6031** CAPI3REF: Deprecated Soft Heap Limit Interface 6032** DEPRECATED 6033** 6034** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 6035** interface. This routine is provided for historical compatibility 6036** only. All new applications should use the 6037** [sqlite3_soft_heap_limit64()] interface rather than this one. 6038*/ 6039SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 6040 6041 6042/* 6043** CAPI3REF: Extract Metadata About A Column Of A Table 6044** METHOD: sqlite3 6045** 6046** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 6047** information about column C of table T in database D 6048** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 6049** interface returns SQLITE_OK and fills in the non-NULL pointers in 6050** the final five arguments with appropriate values if the specified 6051** column exists. ^The sqlite3_table_column_metadata() interface returns 6052** SQLITE_ERROR and if the specified column does not exist. 6053** ^If the column-name parameter to sqlite3_table_column_metadata() is a 6054** NULL pointer, then this routine simply checks for the existence of the 6055** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 6056** does not. If the table name parameter T in a call to 6057** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 6058** undefined behavior. 6059** 6060** ^The column is identified by the second, third and fourth parameters to 6061** this function. ^(The second parameter is either the name of the database 6062** (i.e. "main", "temp", or an attached database) containing the specified 6063** table or NULL.)^ ^If it is NULL, then all attached databases are searched 6064** for the table using the same algorithm used by the database engine to 6065** resolve unqualified table references. 6066** 6067** ^The third and fourth parameters to this function are the table and column 6068** name of the desired column, respectively. 6069** 6070** ^Metadata is returned by writing to the memory locations passed as the 5th 6071** and subsequent parameters to this function. ^Any of these arguments may be 6072** NULL, in which case the corresponding element of metadata is omitted. 6073** 6074** ^(<blockquote> 6075** <table border="1"> 6076** <tr><th> Parameter <th> Output<br>Type <th> Description 6077** 6078** <tr><td> 5th <td> const char* <td> Data type 6079** <tr><td> 6th <td> const char* <td> Name of default collation sequence 6080** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 6081** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 6082** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 6083** </table> 6084** </blockquote>)^ 6085** 6086** ^The memory pointed to by the character pointers returned for the 6087** declaration type and collation sequence is valid until the next 6088** call to any SQLite API function. 6089** 6090** ^If the specified table is actually a view, an [error code] is returned. 6091** 6092** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 6093** is not a [WITHOUT ROWID] table and an 6094** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 6095** parameters are set for the explicitly declared column. ^(If there is no 6096** [INTEGER PRIMARY KEY] column, then the outputs 6097** for the [rowid] are set as follows: 6098** 6099** <pre> 6100** data type: "INTEGER" 6101** collation sequence: "BINARY" 6102** not null: 0 6103** primary key: 1 6104** auto increment: 0 6105** </pre>)^ 6106** 6107** ^This function causes all database schemas to be read from disk and 6108** parsed, if that has not already been done, and returns an error if 6109** any errors are encountered while loading the schema. 6110*/ 6111int sqlite3_table_column_metadata( 6112 sqlite3 *db, /* Connection handle */ 6113 const char *zDbName, /* Database name or NULL */ 6114 const char *zTableName, /* Table name */ 6115 const char *zColumnName, /* Column name */ 6116 char const **pzDataType, /* OUTPUT: Declared data type */ 6117 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 6118 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 6119 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 6120 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 6121); 6122 6123/* 6124** CAPI3REF: Load An Extension 6125** METHOD: sqlite3 6126** 6127** ^This interface loads an SQLite extension library from the named file. 6128** 6129** ^The sqlite3_load_extension() interface attempts to load an 6130** [SQLite extension] library contained in the file zFile. If 6131** the file cannot be loaded directly, attempts are made to load 6132** with various operating-system specific extensions added. 6133** So for example, if "samplelib" cannot be loaded, then names like 6134** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 6135** be tried also. 6136** 6137** ^The entry point is zProc. 6138** ^(zProc may be 0, in which case SQLite will try to come up with an 6139** entry point name on its own. It first tries "sqlite3_extension_init". 6140** If that does not work, it constructs a name "sqlite3_X_init" where the 6141** X is consists of the lower-case equivalent of all ASCII alphabetic 6142** characters in the filename from the last "/" to the first following 6143** "." and omitting any initial "lib".)^ 6144** ^The sqlite3_load_extension() interface returns 6145** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 6146** ^If an error occurs and pzErrMsg is not 0, then the 6147** [sqlite3_load_extension()] interface shall attempt to 6148** fill *pzErrMsg with error message text stored in memory 6149** obtained from [sqlite3_malloc()]. The calling function 6150** should free this memory by calling [sqlite3_free()]. 6151** 6152** ^Extension loading must be enabled using 6153** [sqlite3_enable_load_extension()] or 6154** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 6155** prior to calling this API, 6156** otherwise an error will be returned. 6157** 6158** <b>Security warning:</b> It is recommended that the 6159** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 6160** interface. The use of the [sqlite3_enable_load_extension()] interface 6161** should be avoided. This will keep the SQL function [load_extension()] 6162** disabled and prevent SQL injections from giving attackers 6163** access to extension loading capabilities. 6164** 6165** See also the [load_extension() SQL function]. 6166*/ 6167int sqlite3_load_extension( 6168 sqlite3 *db, /* Load the extension into this database connection */ 6169 const char *zFile, /* Name of the shared library containing extension */ 6170 const char *zProc, /* Entry point. Derived from zFile if 0 */ 6171 char **pzErrMsg /* Put error message here if not 0 */ 6172); 6173 6174/* 6175** CAPI3REF: Enable Or Disable Extension Loading 6176** METHOD: sqlite3 6177** 6178** ^So as not to open security holes in older applications that are 6179** unprepared to deal with [extension loading], and as a means of disabling 6180** [extension loading] while evaluating user-entered SQL, the following API 6181** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 6182** 6183** ^Extension loading is off by default. 6184** ^Call the sqlite3_enable_load_extension() routine with onoff==1 6185** to turn extension loading on and call it with onoff==0 to turn 6186** it back off again. 6187** 6188** ^This interface enables or disables both the C-API 6189** [sqlite3_load_extension()] and the SQL function [load_extension()]. 6190** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 6191** to enable or disable only the C-API.)^ 6192** 6193** <b>Security warning:</b> It is recommended that extension loading 6194** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 6195** rather than this interface, so the [load_extension()] SQL function 6196** remains disabled. This will prevent SQL injections from giving attackers 6197** access to extension loading capabilities. 6198*/ 6199int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 6200 6201/* 6202** CAPI3REF: Automatically Load Statically Linked Extensions 6203** 6204** ^This interface causes the xEntryPoint() function to be invoked for 6205** each new [database connection] that is created. The idea here is that 6206** xEntryPoint() is the entry point for a statically linked [SQLite extension] 6207** that is to be automatically loaded into all new database connections. 6208** 6209** ^(Even though the function prototype shows that xEntryPoint() takes 6210** no arguments and returns void, SQLite invokes xEntryPoint() with three 6211** arguments and expects an integer result as if the signature of the 6212** entry point where as follows: 6213** 6214** <blockquote><pre> 6215** int xEntryPoint( 6216** sqlite3 *db, 6217** const char **pzErrMsg, 6218** const struct sqlite3_api_routines *pThunk 6219** ); 6220** </pre></blockquote>)^ 6221** 6222** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 6223** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 6224** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 6225** is NULL before calling the xEntryPoint(). ^SQLite will invoke 6226** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 6227** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 6228** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6229** 6230** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6231** on the list of automatic extensions is a harmless no-op. ^No entry point 6232** will be called more than once for each database connection that is opened. 6233** 6234** See also: [sqlite3_reset_auto_extension()] 6235** and [sqlite3_cancel_auto_extension()] 6236*/ 6237int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6238 6239/* 6240** CAPI3REF: Cancel Automatic Extension Loading 6241** 6242** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6243** initialization routine X that was registered using a prior call to 6244** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6245** routine returns 1 if initialization routine X was successfully 6246** unregistered and it returns 0 if X was not on the list of initialization 6247** routines. 6248*/ 6249int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6250 6251/* 6252** CAPI3REF: Reset Automatic Extension Loading 6253** 6254** ^This interface disables all automatic extensions previously 6255** registered using [sqlite3_auto_extension()]. 6256*/ 6257void sqlite3_reset_auto_extension(void); 6258 6259/* 6260** The interface to the virtual-table mechanism is currently considered 6261** to be experimental. The interface might change in incompatible ways. 6262** If this is a problem for you, do not use the interface at this time. 6263** 6264** When the virtual-table mechanism stabilizes, we will declare the 6265** interface fixed, support it indefinitely, and remove this comment. 6266*/ 6267 6268/* 6269** Structures used by the virtual table interface 6270*/ 6271typedef struct sqlite3_vtab sqlite3_vtab; 6272typedef struct sqlite3_index_info sqlite3_index_info; 6273typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6274typedef struct sqlite3_module sqlite3_module; 6275 6276/* 6277** CAPI3REF: Virtual Table Object 6278** KEYWORDS: sqlite3_module {virtual table module} 6279** 6280** This structure, sometimes called a "virtual table module", 6281** defines the implementation of a [virtual tables]. 6282** This structure consists mostly of methods for the module. 6283** 6284** ^A virtual table module is created by filling in a persistent 6285** instance of this structure and passing a pointer to that instance 6286** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6287** ^The registration remains valid until it is replaced by a different 6288** module or until the [database connection] closes. The content 6289** of this structure must not change while it is registered with 6290** any database connection. 6291*/ 6292struct sqlite3_module { 6293 int iVersion; 6294 int (*xCreate)(sqlite3*, void *pAux, 6295 int argc, const char *const*argv, 6296 sqlite3_vtab **ppVTab, char**); 6297 int (*xConnect)(sqlite3*, void *pAux, 6298 int argc, const char *const*argv, 6299 sqlite3_vtab **ppVTab, char**); 6300 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6301 int (*xDisconnect)(sqlite3_vtab *pVTab); 6302 int (*xDestroy)(sqlite3_vtab *pVTab); 6303 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6304 int (*xClose)(sqlite3_vtab_cursor*); 6305 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6306 int argc, sqlite3_value **argv); 6307 int (*xNext)(sqlite3_vtab_cursor*); 6308 int (*xEof)(sqlite3_vtab_cursor*); 6309 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6310 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6311 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6312 int (*xBegin)(sqlite3_vtab *pVTab); 6313 int (*xSync)(sqlite3_vtab *pVTab); 6314 int (*xCommit)(sqlite3_vtab *pVTab); 6315 int (*xRollback)(sqlite3_vtab *pVTab); 6316 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6317 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6318 void **ppArg); 6319 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6320 /* The methods above are in version 1 of the sqlite_module object. Those 6321 ** below are for version 2 and greater. */ 6322 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6323 int (*xRelease)(sqlite3_vtab *pVTab, int); 6324 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6325 /* The methods above are in versions 1 and 2 of the sqlite_module object. 6326 ** Those below are for version 3 and greater. */ 6327 int (*xShadowName)(const char*); 6328}; 6329 6330/* 6331** CAPI3REF: Virtual Table Indexing Information 6332** KEYWORDS: sqlite3_index_info 6333** 6334** The sqlite3_index_info structure and its substructures is used as part 6335** of the [virtual table] interface to 6336** pass information into and receive the reply from the [xBestIndex] 6337** method of a [virtual table module]. The fields under **Inputs** are the 6338** inputs to xBestIndex and are read-only. xBestIndex inserts its 6339** results into the **Outputs** fields. 6340** 6341** ^(The aConstraint[] array records WHERE clause constraints of the form: 6342** 6343** <blockquote>column OP expr</blockquote> 6344** 6345** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6346** stored in aConstraint[].op using one of the 6347** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6348** ^(The index of the column is stored in 6349** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6350** expr on the right-hand side can be evaluated (and thus the constraint 6351** is usable) and false if it cannot.)^ 6352** 6353** ^The optimizer automatically inverts terms of the form "expr OP column" 6354** and makes other simplifications to the WHERE clause in an attempt to 6355** get as many WHERE clause terms into the form shown above as possible. 6356** ^The aConstraint[] array only reports WHERE clause terms that are 6357** relevant to the particular virtual table being queried. 6358** 6359** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6360** ^Each term of aOrderBy records a column of the ORDER BY clause. 6361** 6362** The colUsed field indicates which columns of the virtual table may be 6363** required by the current scan. Virtual table columns are numbered from 6364** zero in the order in which they appear within the CREATE TABLE statement 6365** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6366** the corresponding bit is set within the colUsed mask if the column may be 6367** required by SQLite. If the table has at least 64 columns and any column 6368** to the right of the first 63 is required, then bit 63 of colUsed is also 6369** set. In other words, column iCol may be required if the expression 6370** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6371** non-zero. 6372** 6373** The [xBestIndex] method must fill aConstraintUsage[] with information 6374** about what parameters to pass to xFilter. ^If argvIndex>0 then 6375** the right-hand side of the corresponding aConstraint[] is evaluated 6376** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6377** is true, then the constraint is assumed to be fully handled by the 6378** virtual table and is not checked again by SQLite.)^ 6379** 6380** ^The idxNum and idxPtr values are recorded and passed into the 6381** [xFilter] method. 6382** ^[sqlite3_free()] is used to free idxPtr if and only if 6383** needToFreeIdxPtr is true. 6384** 6385** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6386** the correct order to satisfy the ORDER BY clause so that no separate 6387** sorting step is required. 6388** 6389** ^The estimatedCost value is an estimate of the cost of a particular 6390** strategy. A cost of N indicates that the cost of the strategy is similar 6391** to a linear scan of an SQLite table with N rows. A cost of log(N) 6392** indicates that the expense of the operation is similar to that of a 6393** binary search on a unique indexed field of an SQLite table with N rows. 6394** 6395** ^The estimatedRows value is an estimate of the number of rows that 6396** will be returned by the strategy. 6397** 6398** The xBestIndex method may optionally populate the idxFlags field with a 6399** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6400** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6401** assumes that the strategy may visit at most one row. 6402** 6403** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6404** SQLite also assumes that if a call to the xUpdate() method is made as 6405** part of the same statement to delete or update a virtual table row and the 6406** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6407** any database changes. In other words, if the xUpdate() returns 6408** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6409** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6410** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6411** the xUpdate method are automatically rolled back by SQLite. 6412** 6413** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6414** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6415** If a virtual table extension is 6416** used with an SQLite version earlier than 3.8.2, the results of attempting 6417** to read or write the estimatedRows field are undefined (but are likely 6418** to included crashing the application). The estimatedRows field should 6419** therefore only be used if [sqlite3_libversion_number()] returns a 6420** value greater than or equal to 3008002. Similarly, the idxFlags field 6421** was added for [version 3.9.0] ([dateof:3.9.0]). 6422** It may therefore only be used if 6423** sqlite3_libversion_number() returns a value greater than or equal to 6424** 3009000. 6425*/ 6426struct sqlite3_index_info { 6427 /* Inputs */ 6428 int nConstraint; /* Number of entries in aConstraint */ 6429 struct sqlite3_index_constraint { 6430 int iColumn; /* Column constrained. -1 for ROWID */ 6431 unsigned char op; /* Constraint operator */ 6432 unsigned char usable; /* True if this constraint is usable */ 6433 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6434 } *aConstraint; /* Table of WHERE clause constraints */ 6435 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6436 struct sqlite3_index_orderby { 6437 int iColumn; /* Column number */ 6438 unsigned char desc; /* True for DESC. False for ASC. */ 6439 } *aOrderBy; /* The ORDER BY clause */ 6440 /* Outputs */ 6441 struct sqlite3_index_constraint_usage { 6442 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6443 unsigned char omit; /* Do not code a test for this constraint */ 6444 } *aConstraintUsage; 6445 int idxNum; /* Number used to identify the index */ 6446 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6447 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6448 int orderByConsumed; /* True if output is already ordered */ 6449 double estimatedCost; /* Estimated cost of using this index */ 6450 /* Fields below are only available in SQLite 3.8.2 and later */ 6451 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6452 /* Fields below are only available in SQLite 3.9.0 and later */ 6453 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6454 /* Fields below are only available in SQLite 3.10.0 and later */ 6455 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6456}; 6457 6458/* 6459** CAPI3REF: Virtual Table Scan Flags 6460** 6461** Virtual table implementations are allowed to set the 6462** [sqlite3_index_info].idxFlags field to some combination of 6463** these bits. 6464*/ 6465#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6466 6467/* 6468** CAPI3REF: Virtual Table Constraint Operator Codes 6469** 6470** These macros defined the allowed values for the 6471** [sqlite3_index_info].aConstraint[].op field. Each value represents 6472** an operator that is part of a constraint term in the wHERE clause of 6473** a query that uses a [virtual table]. 6474*/ 6475#define SQLITE_INDEX_CONSTRAINT_EQ 2 6476#define SQLITE_INDEX_CONSTRAINT_GT 4 6477#define SQLITE_INDEX_CONSTRAINT_LE 8 6478#define SQLITE_INDEX_CONSTRAINT_LT 16 6479#define SQLITE_INDEX_CONSTRAINT_GE 32 6480#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6481#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6482#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6483#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6484#define SQLITE_INDEX_CONSTRAINT_NE 68 6485#define SQLITE_INDEX_CONSTRAINT_ISNOT 69 6486#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70 6487#define SQLITE_INDEX_CONSTRAINT_ISNULL 71 6488#define SQLITE_INDEX_CONSTRAINT_IS 72 6489#define SQLITE_INDEX_CONSTRAINT_FUNCTION 150 6490 6491/* 6492** CAPI3REF: Register A Virtual Table Implementation 6493** METHOD: sqlite3 6494** 6495** ^These routines are used to register a new [virtual table module] name. 6496** ^Module names must be registered before 6497** creating a new [virtual table] using the module and before using a 6498** preexisting [virtual table] for the module. 6499** 6500** ^The module name is registered on the [database connection] specified 6501** by the first parameter. ^The name of the module is given by the 6502** second parameter. ^The third parameter is a pointer to 6503** the implementation of the [virtual table module]. ^The fourth 6504** parameter is an arbitrary client data pointer that is passed through 6505** into the [xCreate] and [xConnect] methods of the virtual table module 6506** when a new virtual table is be being created or reinitialized. 6507** 6508** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6509** is a pointer to a destructor for the pClientData. ^SQLite will 6510** invoke the destructor function (if it is not NULL) when SQLite 6511** no longer needs the pClientData pointer. ^The destructor will also 6512** be invoked if the call to sqlite3_create_module_v2() fails. 6513** ^The sqlite3_create_module() 6514** interface is equivalent to sqlite3_create_module_v2() with a NULL 6515** destructor. 6516*/ 6517int sqlite3_create_module( 6518 sqlite3 *db, /* SQLite connection to register module with */ 6519 const char *zName, /* Name of the module */ 6520 const sqlite3_module *p, /* Methods for the module */ 6521 void *pClientData /* Client data for xCreate/xConnect */ 6522); 6523int sqlite3_create_module_v2( 6524 sqlite3 *db, /* SQLite connection to register module with */ 6525 const char *zName, /* Name of the module */ 6526 const sqlite3_module *p, /* Methods for the module */ 6527 void *pClientData, /* Client data for xCreate/xConnect */ 6528 void(*xDestroy)(void*) /* Module destructor function */ 6529); 6530 6531/* 6532** CAPI3REF: Virtual Table Instance Object 6533** KEYWORDS: sqlite3_vtab 6534** 6535** Every [virtual table module] implementation uses a subclass 6536** of this object to describe a particular instance 6537** of the [virtual table]. Each subclass will 6538** be tailored to the specific needs of the module implementation. 6539** The purpose of this superclass is to define certain fields that are 6540** common to all module implementations. 6541** 6542** ^Virtual tables methods can set an error message by assigning a 6543** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 6544** take care that any prior string is freed by a call to [sqlite3_free()] 6545** prior to assigning a new string to zErrMsg. ^After the error message 6546** is delivered up to the client application, the string will be automatically 6547** freed by sqlite3_free() and the zErrMsg field will be zeroed. 6548*/ 6549struct sqlite3_vtab { 6550 const sqlite3_module *pModule; /* The module for this virtual table */ 6551 int nRef; /* Number of open cursors */ 6552 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 6553 /* Virtual table implementations will typically add additional fields */ 6554}; 6555 6556/* 6557** CAPI3REF: Virtual Table Cursor Object 6558** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 6559** 6560** Every [virtual table module] implementation uses a subclass of the 6561** following structure to describe cursors that point into the 6562** [virtual table] and are used 6563** to loop through the virtual table. Cursors are created using the 6564** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 6565** by the [sqlite3_module.xClose | xClose] method. Cursors are used 6566** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 6567** of the module. Each module implementation will define 6568** the content of a cursor structure to suit its own needs. 6569** 6570** This superclass exists in order to define fields of the cursor that 6571** are common to all implementations. 6572*/ 6573struct sqlite3_vtab_cursor { 6574 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 6575 /* Virtual table implementations will typically add additional fields */ 6576}; 6577 6578/* 6579** CAPI3REF: Declare The Schema Of A Virtual Table 6580** 6581** ^The [xCreate] and [xConnect] methods of a 6582** [virtual table module] call this interface 6583** to declare the format (the names and datatypes of the columns) of 6584** the virtual tables they implement. 6585*/ 6586int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 6587 6588/* 6589** CAPI3REF: Overload A Function For A Virtual Table 6590** METHOD: sqlite3 6591** 6592** ^(Virtual tables can provide alternative implementations of functions 6593** using the [xFindFunction] method of the [virtual table module]. 6594** But global versions of those functions 6595** must exist in order to be overloaded.)^ 6596** 6597** ^(This API makes sure a global version of a function with a particular 6598** name and number of parameters exists. If no such function exists 6599** before this API is called, a new function is created.)^ ^The implementation 6600** of the new function always causes an exception to be thrown. So 6601** the new function is not good for anything by itself. Its only 6602** purpose is to be a placeholder function that can be overloaded 6603** by a [virtual table]. 6604*/ 6605int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 6606 6607/* 6608** The interface to the virtual-table mechanism defined above (back up 6609** to a comment remarkably similar to this one) is currently considered 6610** to be experimental. The interface might change in incompatible ways. 6611** If this is a problem for you, do not use the interface at this time. 6612** 6613** When the virtual-table mechanism stabilizes, we will declare the 6614** interface fixed, support it indefinitely, and remove this comment. 6615*/ 6616 6617/* 6618** CAPI3REF: A Handle To An Open BLOB 6619** KEYWORDS: {BLOB handle} {BLOB handles} 6620** 6621** An instance of this object represents an open BLOB on which 6622** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 6623** ^Objects of this type are created by [sqlite3_blob_open()] 6624** and destroyed by [sqlite3_blob_close()]. 6625** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 6626** can be used to read or write small subsections of the BLOB. 6627** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 6628*/ 6629typedef struct sqlite3_blob sqlite3_blob; 6630 6631/* 6632** CAPI3REF: Open A BLOB For Incremental I/O 6633** METHOD: sqlite3 6634** CONSTRUCTOR: sqlite3_blob 6635** 6636** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 6637** in row iRow, column zColumn, table zTable in database zDb; 6638** in other words, the same BLOB that would be selected by: 6639** 6640** <pre> 6641** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 6642** </pre>)^ 6643** 6644** ^(Parameter zDb is not the filename that contains the database, but 6645** rather the symbolic name of the database. For attached databases, this is 6646** the name that appears after the AS keyword in the [ATTACH] statement. 6647** For the main database file, the database name is "main". For TEMP 6648** tables, the database name is "temp".)^ 6649** 6650** ^If the flags parameter is non-zero, then the BLOB is opened for read 6651** and write access. ^If the flags parameter is zero, the BLOB is opened for 6652** read-only access. 6653** 6654** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 6655** in *ppBlob. Otherwise an [error code] is returned and, unless the error 6656** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 6657** the API is not misused, it is always safe to call [sqlite3_blob_close()] 6658** on *ppBlob after this function it returns. 6659** 6660** This function fails with SQLITE_ERROR if any of the following are true: 6661** <ul> 6662** <li> ^(Database zDb does not exist)^, 6663** <li> ^(Table zTable does not exist within database zDb)^, 6664** <li> ^(Table zTable is a WITHOUT ROWID table)^, 6665** <li> ^(Column zColumn does not exist)^, 6666** <li> ^(Row iRow is not present in the table)^, 6667** <li> ^(The specified column of row iRow contains a value that is not 6668** a TEXT or BLOB value)^, 6669** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 6670** constraint and the blob is being opened for read/write access)^, 6671** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 6672** column zColumn is part of a [child key] definition and the blob is 6673** being opened for read/write access)^. 6674** </ul> 6675** 6676** ^Unless it returns SQLITE_MISUSE, this function sets the 6677** [database connection] error code and message accessible via 6678** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6679** 6680** A BLOB referenced by sqlite3_blob_open() may be read using the 6681** [sqlite3_blob_read()] interface and modified by using 6682** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 6683** different row of the same table using the [sqlite3_blob_reopen()] 6684** interface. However, the column, table, or database of a [BLOB handle] 6685** cannot be changed after the [BLOB handle] is opened. 6686** 6687** ^(If the row that a BLOB handle points to is modified by an 6688** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 6689** then the BLOB handle is marked as "expired". 6690** This is true if any column of the row is changed, even a column 6691** other than the one the BLOB handle is open on.)^ 6692** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 6693** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 6694** ^(Changes written into a BLOB prior to the BLOB expiring are not 6695** rolled back by the expiration of the BLOB. Such changes will eventually 6696** commit if the transaction continues to completion.)^ 6697** 6698** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 6699** the opened blob. ^The size of a blob may not be changed by this 6700** interface. Use the [UPDATE] SQL command to change the size of a 6701** blob. 6702** 6703** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 6704** and the built-in [zeroblob] SQL function may be used to create a 6705** zero-filled blob to read or write using the incremental-blob interface. 6706** 6707** To avoid a resource leak, every open [BLOB handle] should eventually 6708** be released by a call to [sqlite3_blob_close()]. 6709** 6710** See also: [sqlite3_blob_close()], 6711** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 6712** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 6713*/ 6714int sqlite3_blob_open( 6715 sqlite3*, 6716 const char *zDb, 6717 const char *zTable, 6718 const char *zColumn, 6719 sqlite3_int64 iRow, 6720 int flags, 6721 sqlite3_blob **ppBlob 6722); 6723 6724/* 6725** CAPI3REF: Move a BLOB Handle to a New Row 6726** METHOD: sqlite3_blob 6727** 6728** ^This function is used to move an existing [BLOB handle] so that it points 6729** to a different row of the same database table. ^The new row is identified 6730** by the rowid value passed as the second argument. Only the row can be 6731** changed. ^The database, table and column on which the blob handle is open 6732** remain the same. Moving an existing [BLOB handle] to a new row is 6733** faster than closing the existing handle and opening a new one. 6734** 6735** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 6736** it must exist and there must be either a blob or text value stored in 6737** the nominated column.)^ ^If the new row is not present in the table, or if 6738** it does not contain a blob or text value, or if another error occurs, an 6739** SQLite error code is returned and the blob handle is considered aborted. 6740** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 6741** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 6742** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 6743** always returns zero. 6744** 6745** ^This function sets the database handle error code and message. 6746*/ 6747int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 6748 6749/* 6750** CAPI3REF: Close A BLOB Handle 6751** DESTRUCTOR: sqlite3_blob 6752** 6753** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 6754** unconditionally. Even if this routine returns an error code, the 6755** handle is still closed.)^ 6756** 6757** ^If the blob handle being closed was opened for read-write access, and if 6758** the database is in auto-commit mode and there are no other open read-write 6759** blob handles or active write statements, the current transaction is 6760** committed. ^If an error occurs while committing the transaction, an error 6761** code is returned and the transaction rolled back. 6762** 6763** Calling this function with an argument that is not a NULL pointer or an 6764** open blob handle results in undefined behaviour. ^Calling this routine 6765** with a null pointer (such as would be returned by a failed call to 6766** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 6767** is passed a valid open blob handle, the values returned by the 6768** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 6769*/ 6770int sqlite3_blob_close(sqlite3_blob *); 6771 6772/* 6773** CAPI3REF: Return The Size Of An Open BLOB 6774** METHOD: sqlite3_blob 6775** 6776** ^Returns the size in bytes of the BLOB accessible via the 6777** successfully opened [BLOB handle] in its only argument. ^The 6778** incremental blob I/O routines can only read or overwriting existing 6779** blob content; they cannot change the size of a blob. 6780** 6781** This routine only works on a [BLOB handle] which has been created 6782** by a prior successful call to [sqlite3_blob_open()] and which has not 6783** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6784** to this routine results in undefined and probably undesirable behavior. 6785*/ 6786int sqlite3_blob_bytes(sqlite3_blob *); 6787 6788/* 6789** CAPI3REF: Read Data From A BLOB Incrementally 6790** METHOD: sqlite3_blob 6791** 6792** ^(This function is used to read data from an open [BLOB handle] into a 6793** caller-supplied buffer. N bytes of data are copied into buffer Z 6794** from the open BLOB, starting at offset iOffset.)^ 6795** 6796** ^If offset iOffset is less than N bytes from the end of the BLOB, 6797** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6798** less than zero, [SQLITE_ERROR] is returned and no data is read. 6799** ^The size of the blob (and hence the maximum value of N+iOffset) 6800** can be determined using the [sqlite3_blob_bytes()] interface. 6801** 6802** ^An attempt to read from an expired [BLOB handle] fails with an 6803** error code of [SQLITE_ABORT]. 6804** 6805** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6806** Otherwise, an [error code] or an [extended error code] is returned.)^ 6807** 6808** This routine only works on a [BLOB handle] which has been created 6809** by a prior successful call to [sqlite3_blob_open()] and which has not 6810** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6811** to this routine results in undefined and probably undesirable behavior. 6812** 6813** See also: [sqlite3_blob_write()]. 6814*/ 6815int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6816 6817/* 6818** CAPI3REF: Write Data Into A BLOB Incrementally 6819** METHOD: sqlite3_blob 6820** 6821** ^(This function is used to write data into an open [BLOB handle] from a 6822** caller-supplied buffer. N bytes of data are copied from the buffer Z 6823** into the open BLOB, starting at offset iOffset.)^ 6824** 6825** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6826** Otherwise, an [error code] or an [extended error code] is returned.)^ 6827** ^Unless SQLITE_MISUSE is returned, this function sets the 6828** [database connection] error code and message accessible via 6829** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6830** 6831** ^If the [BLOB handle] passed as the first argument was not opened for 6832** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6833** this function returns [SQLITE_READONLY]. 6834** 6835** This function may only modify the contents of the BLOB; it is 6836** not possible to increase the size of a BLOB using this API. 6837** ^If offset iOffset is less than N bytes from the end of the BLOB, 6838** [SQLITE_ERROR] is returned and no data is written. The size of the 6839** BLOB (and hence the maximum value of N+iOffset) can be determined 6840** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6841** than zero [SQLITE_ERROR] is returned and no data is written. 6842** 6843** ^An attempt to write to an expired [BLOB handle] fails with an 6844** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6845** before the [BLOB handle] expired are not rolled back by the 6846** expiration of the handle, though of course those changes might 6847** have been overwritten by the statement that expired the BLOB handle 6848** or by other independent statements. 6849** 6850** This routine only works on a [BLOB handle] which has been created 6851** by a prior successful call to [sqlite3_blob_open()] and which has not 6852** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6853** to this routine results in undefined and probably undesirable behavior. 6854** 6855** See also: [sqlite3_blob_read()]. 6856*/ 6857int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6858 6859/* 6860** CAPI3REF: Virtual File System Objects 6861** 6862** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6863** that SQLite uses to interact 6864** with the underlying operating system. Most SQLite builds come with a 6865** single default VFS that is appropriate for the host computer. 6866** New VFSes can be registered and existing VFSes can be unregistered. 6867** The following interfaces are provided. 6868** 6869** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6870** ^Names are case sensitive. 6871** ^Names are zero-terminated UTF-8 strings. 6872** ^If there is no match, a NULL pointer is returned. 6873** ^If zVfsName is NULL then the default VFS is returned. 6874** 6875** ^New VFSes are registered with sqlite3_vfs_register(). 6876** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6877** ^The same VFS can be registered multiple times without injury. 6878** ^To make an existing VFS into the default VFS, register it again 6879** with the makeDflt flag set. If two different VFSes with the 6880** same name are registered, the behavior is undefined. If a 6881** VFS is registered with a name that is NULL or an empty string, 6882** then the behavior is undefined. 6883** 6884** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6885** ^(If the default VFS is unregistered, another VFS is chosen as 6886** the default. The choice for the new VFS is arbitrary.)^ 6887*/ 6888sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6889int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6890int sqlite3_vfs_unregister(sqlite3_vfs*); 6891 6892/* 6893** CAPI3REF: Mutexes 6894** 6895** The SQLite core uses these routines for thread 6896** synchronization. Though they are intended for internal 6897** use by SQLite, code that links against SQLite is 6898** permitted to use any of these routines. 6899** 6900** The SQLite source code contains multiple implementations 6901** of these mutex routines. An appropriate implementation 6902** is selected automatically at compile-time. The following 6903** implementations are available in the SQLite core: 6904** 6905** <ul> 6906** <li> SQLITE_MUTEX_PTHREADS 6907** <li> SQLITE_MUTEX_W32 6908** <li> SQLITE_MUTEX_NOOP 6909** </ul> 6910** 6911** The SQLITE_MUTEX_NOOP implementation is a set of routines 6912** that does no real locking and is appropriate for use in 6913** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6914** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6915** and Windows. 6916** 6917** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6918** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6919** implementation is included with the library. In this case the 6920** application must supply a custom mutex implementation using the 6921** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6922** before calling sqlite3_initialize() or any other public sqlite3_ 6923** function that calls sqlite3_initialize(). 6924** 6925** ^The sqlite3_mutex_alloc() routine allocates a new 6926** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6927** routine returns NULL if it is unable to allocate the requested 6928** mutex. The argument to sqlite3_mutex_alloc() must one of these 6929** integer constants: 6930** 6931** <ul> 6932** <li> SQLITE_MUTEX_FAST 6933** <li> SQLITE_MUTEX_RECURSIVE 6934** <li> SQLITE_MUTEX_STATIC_MASTER 6935** <li> SQLITE_MUTEX_STATIC_MEM 6936** <li> SQLITE_MUTEX_STATIC_OPEN 6937** <li> SQLITE_MUTEX_STATIC_PRNG 6938** <li> SQLITE_MUTEX_STATIC_LRU 6939** <li> SQLITE_MUTEX_STATIC_PMEM 6940** <li> SQLITE_MUTEX_STATIC_APP1 6941** <li> SQLITE_MUTEX_STATIC_APP2 6942** <li> SQLITE_MUTEX_STATIC_APP3 6943** <li> SQLITE_MUTEX_STATIC_VFS1 6944** <li> SQLITE_MUTEX_STATIC_VFS2 6945** <li> SQLITE_MUTEX_STATIC_VFS3 6946** </ul> 6947** 6948** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6949** cause sqlite3_mutex_alloc() to create 6950** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6951** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6952** The mutex implementation does not need to make a distinction 6953** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6954** not want to. SQLite will only request a recursive mutex in 6955** cases where it really needs one. If a faster non-recursive mutex 6956** implementation is available on the host platform, the mutex subsystem 6957** might return such a mutex in response to SQLITE_MUTEX_FAST. 6958** 6959** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6960** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6961** a pointer to a static preexisting mutex. ^Nine static mutexes are 6962** used by the current version of SQLite. Future versions of SQLite 6963** may add additional static mutexes. Static mutexes are for internal 6964** use by SQLite only. Applications that use SQLite mutexes should 6965** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6966** SQLITE_MUTEX_RECURSIVE. 6967** 6968** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6969** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6970** returns a different mutex on every call. ^For the static 6971** mutex types, the same mutex is returned on every call that has 6972** the same type number. 6973** 6974** ^The sqlite3_mutex_free() routine deallocates a previously 6975** allocated dynamic mutex. Attempting to deallocate a static 6976** mutex results in undefined behavior. 6977** 6978** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6979** to enter a mutex. ^If another thread is already within the mutex, 6980** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6981** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6982** upon successful entry. ^(Mutexes created using 6983** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6984** In such cases, the 6985** mutex must be exited an equal number of times before another thread 6986** can enter.)^ If the same thread tries to enter any mutex other 6987** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6988** 6989** ^(Some systems (for example, Windows 95) do not support the operation 6990** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6991** will always return SQLITE_BUSY. The SQLite core only ever uses 6992** sqlite3_mutex_try() as an optimization so this is acceptable 6993** behavior.)^ 6994** 6995** ^The sqlite3_mutex_leave() routine exits a mutex that was 6996** previously entered by the same thread. The behavior 6997** is undefined if the mutex is not currently entered by the 6998** calling thread or is not currently allocated. 6999** 7000** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 7001** sqlite3_mutex_leave() is a NULL pointer, then all three routines 7002** behave as no-ops. 7003** 7004** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 7005*/ 7006sqlite3_mutex *sqlite3_mutex_alloc(int); 7007void sqlite3_mutex_free(sqlite3_mutex*); 7008void sqlite3_mutex_enter(sqlite3_mutex*); 7009int sqlite3_mutex_try(sqlite3_mutex*); 7010void sqlite3_mutex_leave(sqlite3_mutex*); 7011 7012/* 7013** CAPI3REF: Mutex Methods Object 7014** 7015** An instance of this structure defines the low-level routines 7016** used to allocate and use mutexes. 7017** 7018** Usually, the default mutex implementations provided by SQLite are 7019** sufficient, however the application has the option of substituting a custom 7020** implementation for specialized deployments or systems for which SQLite 7021** does not provide a suitable implementation. In this case, the application 7022** creates and populates an instance of this structure to pass 7023** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 7024** Additionally, an instance of this structure can be used as an 7025** output variable when querying the system for the current mutex 7026** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 7027** 7028** ^The xMutexInit method defined by this structure is invoked as 7029** part of system initialization by the sqlite3_initialize() function. 7030** ^The xMutexInit routine is called by SQLite exactly once for each 7031** effective call to [sqlite3_initialize()]. 7032** 7033** ^The xMutexEnd method defined by this structure is invoked as 7034** part of system shutdown by the sqlite3_shutdown() function. The 7035** implementation of this method is expected to release all outstanding 7036** resources obtained by the mutex methods implementation, especially 7037** those obtained by the xMutexInit method. ^The xMutexEnd() 7038** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 7039** 7040** ^(The remaining seven methods defined by this structure (xMutexAlloc, 7041** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 7042** xMutexNotheld) implement the following interfaces (respectively): 7043** 7044** <ul> 7045** <li> [sqlite3_mutex_alloc()] </li> 7046** <li> [sqlite3_mutex_free()] </li> 7047** <li> [sqlite3_mutex_enter()] </li> 7048** <li> [sqlite3_mutex_try()] </li> 7049** <li> [sqlite3_mutex_leave()] </li> 7050** <li> [sqlite3_mutex_held()] </li> 7051** <li> [sqlite3_mutex_notheld()] </li> 7052** </ul>)^ 7053** 7054** The only difference is that the public sqlite3_XXX functions enumerated 7055** above silently ignore any invocations that pass a NULL pointer instead 7056** of a valid mutex handle. The implementations of the methods defined 7057** by this structure are not required to handle this case, the results 7058** of passing a NULL pointer instead of a valid mutex handle are undefined 7059** (i.e. it is acceptable to provide an implementation that segfaults if 7060** it is passed a NULL pointer). 7061** 7062** The xMutexInit() method must be threadsafe. It must be harmless to 7063** invoke xMutexInit() multiple times within the same process and without 7064** intervening calls to xMutexEnd(). Second and subsequent calls to 7065** xMutexInit() must be no-ops. 7066** 7067** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 7068** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 7069** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 7070** memory allocation for a fast or recursive mutex. 7071** 7072** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 7073** called, but only if the prior call to xMutexInit returned SQLITE_OK. 7074** If xMutexInit fails in any way, it is expected to clean up after itself 7075** prior to returning. 7076*/ 7077typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 7078struct sqlite3_mutex_methods { 7079 int (*xMutexInit)(void); 7080 int (*xMutexEnd)(void); 7081 sqlite3_mutex *(*xMutexAlloc)(int); 7082 void (*xMutexFree)(sqlite3_mutex *); 7083 void (*xMutexEnter)(sqlite3_mutex *); 7084 int (*xMutexTry)(sqlite3_mutex *); 7085 void (*xMutexLeave)(sqlite3_mutex *); 7086 int (*xMutexHeld)(sqlite3_mutex *); 7087 int (*xMutexNotheld)(sqlite3_mutex *); 7088}; 7089 7090/* 7091** CAPI3REF: Mutex Verification Routines 7092** 7093** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 7094** are intended for use inside assert() statements. The SQLite core 7095** never uses these routines except inside an assert() and applications 7096** are advised to follow the lead of the core. The SQLite core only 7097** provides implementations for these routines when it is compiled 7098** with the SQLITE_DEBUG flag. External mutex implementations 7099** are only required to provide these routines if SQLITE_DEBUG is 7100** defined and if NDEBUG is not defined. 7101** 7102** These routines should return true if the mutex in their argument 7103** is held or not held, respectively, by the calling thread. 7104** 7105** The implementation is not required to provide versions of these 7106** routines that actually work. If the implementation does not provide working 7107** versions of these routines, it should at least provide stubs that always 7108** return true so that one does not get spurious assertion failures. 7109** 7110** If the argument to sqlite3_mutex_held() is a NULL pointer then 7111** the routine should return 1. This seems counter-intuitive since 7112** clearly the mutex cannot be held if it does not exist. But 7113** the reason the mutex does not exist is because the build is not 7114** using mutexes. And we do not want the assert() containing the 7115** call to sqlite3_mutex_held() to fail, so a non-zero return is 7116** the appropriate thing to do. The sqlite3_mutex_notheld() 7117** interface should also return 1 when given a NULL pointer. 7118*/ 7119#ifndef NDEBUG 7120int sqlite3_mutex_held(sqlite3_mutex*); 7121int sqlite3_mutex_notheld(sqlite3_mutex*); 7122#endif 7123 7124/* 7125** CAPI3REF: Mutex Types 7126** 7127** The [sqlite3_mutex_alloc()] interface takes a single argument 7128** which is one of these integer constants. 7129** 7130** The set of static mutexes may change from one SQLite release to the 7131** next. Applications that override the built-in mutex logic must be 7132** prepared to accommodate additional static mutexes. 7133*/ 7134#define SQLITE_MUTEX_FAST 0 7135#define SQLITE_MUTEX_RECURSIVE 1 7136#define SQLITE_MUTEX_STATIC_MASTER 2 7137#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 7138#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 7139#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 7140#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 7141#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 7142#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 7143#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 7144#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 7145#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 7146#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 7147#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 7148#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 7149#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 7150 7151/* 7152** CAPI3REF: Retrieve the mutex for a database connection 7153** METHOD: sqlite3 7154** 7155** ^This interface returns a pointer the [sqlite3_mutex] object that 7156** serializes access to the [database connection] given in the argument 7157** when the [threading mode] is Serialized. 7158** ^If the [threading mode] is Single-thread or Multi-thread then this 7159** routine returns a NULL pointer. 7160*/ 7161sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 7162 7163/* 7164** CAPI3REF: Low-Level Control Of Database Files 7165** METHOD: sqlite3 7166** KEYWORDS: {file control} 7167** 7168** ^The [sqlite3_file_control()] interface makes a direct call to the 7169** xFileControl method for the [sqlite3_io_methods] object associated 7170** with a particular database identified by the second argument. ^The 7171** name of the database is "main" for the main database or "temp" for the 7172** TEMP database, or the name that appears after the AS keyword for 7173** databases that are added using the [ATTACH] SQL command. 7174** ^A NULL pointer can be used in place of "main" to refer to the 7175** main database file. 7176** ^The third and fourth parameters to this routine 7177** are passed directly through to the second and third parameters of 7178** the xFileControl method. ^The return value of the xFileControl 7179** method becomes the return value of this routine. 7180** 7181** A few opcodes for [sqlite3_file_control()] are handled directly 7182** by the SQLite core and never invoke the 7183** sqlite3_io_methods.xFileControl method. 7184** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes 7185** a pointer to the underlying [sqlite3_file] object to be written into 7186** the space pointed to by the 4th parameter. The 7187** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns 7188** the [sqlite3_file] object associated with the journal file instead of 7189** the main database. The [SQLITE_FCNTL_VFS_POINTER] opcode returns 7190** a pointer to the underlying [sqlite3_vfs] object for the file. 7191** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter 7192** from the pager. 7193** 7194** ^If the second parameter (zDbName) does not match the name of any 7195** open database file, then SQLITE_ERROR is returned. ^This error 7196** code is not remembered and will not be recalled by [sqlite3_errcode()] 7197** or [sqlite3_errmsg()]. The underlying xFileControl method might 7198** also return SQLITE_ERROR. There is no way to distinguish between 7199** an incorrect zDbName and an SQLITE_ERROR return from the underlying 7200** xFileControl method. 7201** 7202** See also: [file control opcodes] 7203*/ 7204int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 7205 7206/* 7207** CAPI3REF: Testing Interface 7208** 7209** ^The sqlite3_test_control() interface is used to read out internal 7210** state of SQLite and to inject faults into SQLite for testing 7211** purposes. ^The first parameter is an operation code that determines 7212** the number, meaning, and operation of all subsequent parameters. 7213** 7214** This interface is not for use by applications. It exists solely 7215** for verifying the correct operation of the SQLite library. Depending 7216** on how the SQLite library is compiled, this interface might not exist. 7217** 7218** The details of the operation codes, their meanings, the parameters 7219** they take, and what they do are all subject to change without notice. 7220** Unlike most of the SQLite API, this function is not guaranteed to 7221** operate consistently from one release to the next. 7222*/ 7223int sqlite3_test_control(int op, ...); 7224 7225/* 7226** CAPI3REF: Testing Interface Operation Codes 7227** 7228** These constants are the valid operation code parameters used 7229** as the first argument to [sqlite3_test_control()]. 7230** 7231** These parameters and their meanings are subject to change 7232** without notice. These values are for testing purposes only. 7233** Applications should not use any of these parameters or the 7234** [sqlite3_test_control()] interface. 7235*/ 7236#define SQLITE_TESTCTRL_FIRST 5 7237#define SQLITE_TESTCTRL_PRNG_SAVE 5 7238#define SQLITE_TESTCTRL_PRNG_RESTORE 6 7239#define SQLITE_TESTCTRL_PRNG_RESET 7 7240#define SQLITE_TESTCTRL_BITVEC_TEST 8 7241#define SQLITE_TESTCTRL_FAULT_INSTALL 9 7242#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 7243#define SQLITE_TESTCTRL_PENDING_BYTE 11 7244#define SQLITE_TESTCTRL_ASSERT 12 7245#define SQLITE_TESTCTRL_ALWAYS 13 7246#define SQLITE_TESTCTRL_RESERVE 14 7247#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7248#define SQLITE_TESTCTRL_ISKEYWORD 16 /* NOT USED */ 7249#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */ 7250#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS 17 7251#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7252#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7253#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7254#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7255#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7256#define SQLITE_TESTCTRL_BYTEORDER 22 7257#define SQLITE_TESTCTRL_ISINIT 23 7258#define SQLITE_TESTCTRL_SORTER_MMAP 24 7259#define SQLITE_TESTCTRL_IMPOSTER 25 7260#define SQLITE_TESTCTRL_PARSER_COVERAGE 26 7261#define SQLITE_TESTCTRL_LAST 26 /* Largest TESTCTRL */ 7262 7263/* 7264** CAPI3REF: SQL Keyword Checking 7265** 7266** These routines provide access to the set of SQL language keywords 7267** recognized by SQLite. Applications can uses these routines to determine 7268** whether or not a specific identifier needs to be escaped (for example, 7269** by enclosing in double-quotes) so as not to confuse the parser. 7270** 7271** The sqlite3_keyword_count() interface returns the number of distinct 7272** keywords understood by SQLite. 7273** 7274** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and 7275** makes *Z point to that keyword expressed as UTF8 and writes the number 7276** of bytes in the keyword into *L. The string that *Z points to is not 7277** zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns 7278** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z 7279** or L are NULL or invalid pointers then calls to 7280** sqlite3_keyword_name(N,Z,L) result in undefined behavior. 7281** 7282** The sqlite3_keyword_check(Z,L) interface checks to see whether or not 7283** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero 7284** if it is and zero if not. 7285** 7286** The parser used by SQLite is forgiving. It is often possible to use 7287** a keyword as an identifier as long as such use does not result in a 7288** parsing ambiguity. For example, the statement 7289** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and 7290** creates a new table named "BEGIN" with three columns named 7291** "REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid 7292** using keywords as identifiers. Common techniques used to avoid keyword 7293** name collisions include: 7294** <ul> 7295** <li> Put all identifier names inside double-quotes. This is the official 7296** SQL way to escape identifier names. 7297** <li> Put identifier names inside [...]. This is not standard SQL, 7298** but it is what SQL Server does and so lots of programmers use this 7299** technique. 7300** <li> Begin every identifier with the letter "Z" as no SQL keywords start 7301** with "Z". 7302** <li> Include a digit somewhere in every identifier name. 7303** </ul> 7304** 7305** Note that the number of keywords understood by SQLite can depend on 7306** compile-time options. For example, "VACUUM" is not a keyword if 7307** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option. Also, 7308** new keywords may be added to future releases of SQLite. 7309*/ 7310int sqlite3_keyword_count(void); 7311int sqlite3_keyword_name(int,const char**,int*); 7312int sqlite3_keyword_check(const char*,int); 7313 7314/* 7315** CAPI3REF: Dynamic String Object 7316** KEYWORDS: {dynamic string} 7317** 7318** An instance of the sqlite3_str object contains a dynamically-sized 7319** string under construction. 7320** 7321** The lifecycle of an sqlite3_str object is as follows: 7322** <ol> 7323** <li> ^The sqlite3_str object is created using [sqlite3_str_new()]. 7324** <li> ^Text is appended to the sqlite3_str object using various 7325** methods, such as [sqlite3_str_appendf()]. 7326** <li> ^The sqlite3_str object is destroyed and the string it created 7327** is returned using the [sqlite3_str_finish()] interface. 7328** </ol> 7329*/ 7330typedef struct sqlite3_str sqlite3_str; 7331 7332/* 7333** CAPI3REF: Create A New Dynamic String Object 7334** CONSTRUCTOR: sqlite3_str 7335** 7336** ^The [sqlite3_str_new(D)] interface allocates and initializes 7337** a new [sqlite3_str] object. To avoid memory leaks, the object returned by 7338** [sqlite3_str_new()] must be freed by a subsequent call to 7339** [sqlite3_str_finish(X)]. 7340** 7341** ^The [sqlite3_str_new(D)] interface always returns a pointer to a 7342** valid [sqlite3_str] object, though in the event of an out-of-memory 7343** error the returned object might be a special singleton that will 7344** silently reject new text, always return SQLITE_NOMEM from 7345** [sqlite3_str_errcode()], always return 0 for 7346** [sqlite3_str_length()], and always return NULL from 7347** [sqlite3_str_finish(X)]. It is always safe to use the value 7348** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter 7349** to any of the other [sqlite3_str] methods. 7350** 7351** The D parameter to [sqlite3_str_new(D)] may be NULL. If the 7352** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum 7353** length of the string contained in the [sqlite3_str] object will be 7354** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead 7355** of [SQLITE_MAX_LENGTH]. 7356*/ 7357sqlite3_str *sqlite3_str_new(sqlite3*); 7358 7359/* 7360** CAPI3REF: Finalize A Dynamic String 7361** DESTRUCTOR: sqlite3_str 7362** 7363** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X 7364** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()] 7365** that contains the constructed string. The calling application should 7366** pass the returned value to [sqlite3_free()] to avoid a memory leak. 7367** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any 7368** errors were encountered during construction of the string. ^The 7369** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the 7370** string in [sqlite3_str] object X is zero bytes long. 7371*/ 7372char *sqlite3_str_finish(sqlite3_str*); 7373 7374/* 7375** CAPI3REF: Add Content To A Dynamic String 7376** METHOD: sqlite3_str 7377** 7378** These interfaces add content to an sqlite3_str object previously obtained 7379** from [sqlite3_str_new()]. 7380** 7381** ^The [sqlite3_str_appendf(X,F,...)] and 7382** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf] 7383** functionality of SQLite to append formatted text onto the end of 7384** [sqlite3_str] object X. 7385** 7386** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S 7387** onto the end of the [sqlite3_str] object X. N must be non-negative. 7388** S must contain at least N non-zero bytes of content. To append a 7389** zero-terminated string in its entirety, use the [sqlite3_str_appendall()] 7390** method instead. 7391** 7392** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of 7393** zero-terminated string S onto the end of [sqlite3_str] object X. 7394** 7395** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the 7396** single-byte character C onto the end of [sqlite3_str] object X. 7397** ^This method can be used, for example, to add whitespace indentation. 7398** 7399** ^The [sqlite3_str_reset(X)] method resets the string under construction 7400** inside [sqlite3_str] object X back to zero bytes in length. 7401** 7402** These methods do not return a result code. ^If an error occurs, that fact 7403** is recorded in the [sqlite3_str] object and can be recovered by a 7404** subsequent call to [sqlite3_str_errcode(X)]. 7405*/ 7406void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...); 7407void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list); 7408void sqlite3_str_append(sqlite3_str*, const char *zIn, int N); 7409void sqlite3_str_appendall(sqlite3_str*, const char *zIn); 7410void sqlite3_str_appendchar(sqlite3_str*, int N, char C); 7411void sqlite3_str_reset(sqlite3_str*); 7412 7413/* 7414** CAPI3REF: Status Of A Dynamic String 7415** METHOD: sqlite3_str 7416** 7417** These interfaces return the current status of an [sqlite3_str] object. 7418** 7419** ^If any prior errors have occurred while constructing the dynamic string 7420** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return 7421** an appropriate error code. ^The [sqlite3_str_errcode(X)] method returns 7422** [SQLITE_NOMEM] following any out-of-memory error, or 7423** [SQLITE_TOOBIG] if the size of the dynamic string exceeds 7424** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors. 7425** 7426** ^The [sqlite3_str_length(X)] method returns the current length, in bytes, 7427** of the dynamic string under construction in [sqlite3_str] object X. 7428** ^The length returned by [sqlite3_str_length(X)] does not include the 7429** zero-termination byte. 7430** 7431** ^The [sqlite3_str_value(X)] method returns a pointer to the current 7432** content of the dynamic string under construction in X. The value 7433** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X 7434** and might be freed or altered by any subsequent method on the same 7435** [sqlite3_str] object. Applications must not used the pointer returned 7436** [sqlite3_str_value(X)] after any subsequent method call on the same 7437** object. ^Applications may change the content of the string returned 7438** by [sqlite3_str_value(X)] as long as they do not write into any bytes 7439** outside the range of 0 to [sqlite3_str_length(X)] and do not read or 7440** write any byte after any subsequent sqlite3_str method call. 7441*/ 7442int sqlite3_str_errcode(sqlite3_str*); 7443int sqlite3_str_length(sqlite3_str*); 7444char *sqlite3_str_value(sqlite3_str*); 7445 7446/* 7447** CAPI3REF: SQLite Runtime Status 7448** 7449** ^These interfaces are used to retrieve runtime status information 7450** about the performance of SQLite, and optionally to reset various 7451** highwater marks. ^The first argument is an integer code for 7452** the specific parameter to measure. ^(Recognized integer codes 7453** are of the form [status parameters | SQLITE_STATUS_...].)^ 7454** ^The current value of the parameter is returned into *pCurrent. 7455** ^The highest recorded value is returned in *pHighwater. ^If the 7456** resetFlag is true, then the highest record value is reset after 7457** *pHighwater is written. ^(Some parameters do not record the highest 7458** value. For those parameters 7459** nothing is written into *pHighwater and the resetFlag is ignored.)^ 7460** ^(Other parameters record only the highwater mark and not the current 7461** value. For these latter parameters nothing is written into *pCurrent.)^ 7462** 7463** ^The sqlite3_status() and sqlite3_status64() routines return 7464** SQLITE_OK on success and a non-zero [error code] on failure. 7465** 7466** If either the current value or the highwater mark is too large to 7467** be represented by a 32-bit integer, then the values returned by 7468** sqlite3_status() are undefined. 7469** 7470** See also: [sqlite3_db_status()] 7471*/ 7472int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 7473int sqlite3_status64( 7474 int op, 7475 sqlite3_int64 *pCurrent, 7476 sqlite3_int64 *pHighwater, 7477 int resetFlag 7478); 7479 7480 7481/* 7482** CAPI3REF: Status Parameters 7483** KEYWORDS: {status parameters} 7484** 7485** These integer constants designate various run-time status parameters 7486** that can be returned by [sqlite3_status()]. 7487** 7488** <dl> 7489** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 7490** <dd>This parameter is the current amount of memory checked out 7491** using [sqlite3_malloc()], either directly or indirectly. The 7492** figure includes calls made to [sqlite3_malloc()] by the application 7493** and internal memory usage by the SQLite library. Auxiliary page-cache 7494** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 7495** this parameter. The amount returned is the sum of the allocation 7496** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 7497** 7498** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 7499** <dd>This parameter records the largest memory allocation request 7500** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 7501** internal equivalents). Only the value returned in the 7502** *pHighwater parameter to [sqlite3_status()] is of interest. 7503** The value written into the *pCurrent parameter is undefined.</dd>)^ 7504** 7505** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 7506** <dd>This parameter records the number of separate memory allocations 7507** currently checked out.</dd>)^ 7508** 7509** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 7510** <dd>This parameter returns the number of pages used out of the 7511** [pagecache memory allocator] that was configured using 7512** [SQLITE_CONFIG_PAGECACHE]. The 7513** value returned is in pages, not in bytes.</dd>)^ 7514** 7515** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 7516** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 7517** <dd>This parameter returns the number of bytes of page cache 7518** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 7519** buffer and where forced to overflow to [sqlite3_malloc()]. The 7520** returned value includes allocations that overflowed because they 7521** where too large (they were larger than the "sz" parameter to 7522** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 7523** no space was left in the page cache.</dd>)^ 7524** 7525** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 7526** <dd>This parameter records the largest memory allocation request 7527** handed to [pagecache memory allocator]. Only the value returned in the 7528** *pHighwater parameter to [sqlite3_status()] is of interest. 7529** The value written into the *pCurrent parameter is undefined.</dd>)^ 7530** 7531** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt> 7532** <dd>No longer used.</dd> 7533** 7534** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 7535** <dd>No longer used.</dd> 7536** 7537** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 7538** <dd>No longer used.</dd> 7539** 7540** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 7541** <dd>The *pHighwater parameter records the deepest parser stack. 7542** The *pCurrent value is undefined. The *pHighwater value is only 7543** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 7544** </dl> 7545** 7546** New status parameters may be added from time to time. 7547*/ 7548#define SQLITE_STATUS_MEMORY_USED 0 7549#define SQLITE_STATUS_PAGECACHE_USED 1 7550#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 7551#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */ 7552#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */ 7553#define SQLITE_STATUS_MALLOC_SIZE 5 7554#define SQLITE_STATUS_PARSER_STACK 6 7555#define SQLITE_STATUS_PAGECACHE_SIZE 7 7556#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */ 7557#define SQLITE_STATUS_MALLOC_COUNT 9 7558 7559/* 7560** CAPI3REF: Database Connection Status 7561** METHOD: sqlite3 7562** 7563** ^This interface is used to retrieve runtime status information 7564** about a single [database connection]. ^The first argument is the 7565** database connection object to be interrogated. ^The second argument 7566** is an integer constant, taken from the set of 7567** [SQLITE_DBSTATUS options], that 7568** determines the parameter to interrogate. The set of 7569** [SQLITE_DBSTATUS options] is likely 7570** to grow in future releases of SQLite. 7571** 7572** ^The current value of the requested parameter is written into *pCur 7573** and the highest instantaneous value is written into *pHiwtr. ^If 7574** the resetFlg is true, then the highest instantaneous value is 7575** reset back down to the current value. 7576** 7577** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 7578** non-zero [error code] on failure. 7579** 7580** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 7581*/ 7582int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 7583 7584/* 7585** CAPI3REF: Status Parameters for database connections 7586** KEYWORDS: {SQLITE_DBSTATUS options} 7587** 7588** These constants are the available integer "verbs" that can be passed as 7589** the second argument to the [sqlite3_db_status()] interface. 7590** 7591** New verbs may be added in future releases of SQLite. Existing verbs 7592** might be discontinued. Applications should check the return code from 7593** [sqlite3_db_status()] to make sure that the call worked. 7594** The [sqlite3_db_status()] interface will return a non-zero error code 7595** if a discontinued or unsupported verb is invoked. 7596** 7597** <dl> 7598** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 7599** <dd>This parameter returns the number of lookaside memory slots currently 7600** checked out.</dd>)^ 7601** 7602** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 7603** <dd>This parameter returns the number malloc attempts that were 7604** satisfied using lookaside memory. Only the high-water value is meaningful; 7605** the current value is always zero.)^ 7606** 7607** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 7608** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 7609** <dd>This parameter returns the number malloc attempts that might have 7610** been satisfied using lookaside memory but failed due to the amount of 7611** memory requested being larger than the lookaside slot size. 7612** Only the high-water value is meaningful; 7613** the current value is always zero.)^ 7614** 7615** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 7616** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 7617** <dd>This parameter returns the number malloc attempts that might have 7618** been satisfied using lookaside memory but failed due to all lookaside 7619** memory already being in use. 7620** Only the high-water value is meaningful; 7621** the current value is always zero.)^ 7622** 7623** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 7624** <dd>This parameter returns the approximate number of bytes of heap 7625** memory used by all pager caches associated with the database connection.)^ 7626** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 7627** 7628** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 7629** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 7630** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 7631** pager cache is shared between two or more connections the bytes of heap 7632** memory used by that pager cache is divided evenly between the attached 7633** connections.)^ In other words, if none of the pager caches associated 7634** with the database connection are shared, this request returns the same 7635** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 7636** shared, the value returned by this call will be smaller than that returned 7637** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 7638** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 7639** 7640** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 7641** <dd>This parameter returns the approximate number of bytes of heap 7642** memory used to store the schema for all databases associated 7643** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 7644** ^The full amount of memory used by the schemas is reported, even if the 7645** schema memory is shared with other database connections due to 7646** [shared cache mode] being enabled. 7647** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 7648** 7649** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 7650** <dd>This parameter returns the approximate number of bytes of heap 7651** and lookaside memory used by all prepared statements associated with 7652** the database connection.)^ 7653** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 7654** </dd> 7655** 7656** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 7657** <dd>This parameter returns the number of pager cache hits that have 7658** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 7659** is always 0. 7660** </dd> 7661** 7662** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 7663** <dd>This parameter returns the number of pager cache misses that have 7664** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 7665** is always 0. 7666** </dd> 7667** 7668** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 7669** <dd>This parameter returns the number of dirty cache entries that have 7670** been written to disk. Specifically, the number of pages written to the 7671** wal file in wal mode databases, or the number of pages written to the 7672** database file in rollback mode databases. Any pages written as part of 7673** transaction rollback or database recovery operations are not included. 7674** If an IO or other error occurs while writing a page to disk, the effect 7675** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 7676** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 7677** </dd> 7678** 7679** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt> 7680** <dd>This parameter returns the number of dirty cache entries that have 7681** been written to disk in the middle of a transaction due to the page 7682** cache overflowing. Transactions are more efficient if they are written 7683** to disk all at once. When pages spill mid-transaction, that introduces 7684** additional overhead. This parameter can be used help identify 7685** inefficiencies that can be resolve by increasing the cache size. 7686** </dd> 7687** 7688** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 7689** <dd>This parameter returns zero for the current value if and only if 7690** all foreign key constraints (deferred or immediate) have been 7691** resolved.)^ ^The highwater mark is always 0. 7692** </dd> 7693** </dl> 7694*/ 7695#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 7696#define SQLITE_DBSTATUS_CACHE_USED 1 7697#define SQLITE_DBSTATUS_SCHEMA_USED 2 7698#define SQLITE_DBSTATUS_STMT_USED 3 7699#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 7700#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 7701#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 7702#define SQLITE_DBSTATUS_CACHE_HIT 7 7703#define SQLITE_DBSTATUS_CACHE_MISS 8 7704#define SQLITE_DBSTATUS_CACHE_WRITE 9 7705#define SQLITE_DBSTATUS_DEFERRED_FKS 10 7706#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 7707#define SQLITE_DBSTATUS_CACHE_SPILL 12 7708#define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */ 7709 7710 7711/* 7712** CAPI3REF: Prepared Statement Status 7713** METHOD: sqlite3_stmt 7714** 7715** ^(Each prepared statement maintains various 7716** [SQLITE_STMTSTATUS counters] that measure the number 7717** of times it has performed specific operations.)^ These counters can 7718** be used to monitor the performance characteristics of the prepared 7719** statements. For example, if the number of table steps greatly exceeds 7720** the number of table searches or result rows, that would tend to indicate 7721** that the prepared statement is using a full table scan rather than 7722** an index. 7723** 7724** ^(This interface is used to retrieve and reset counter values from 7725** a [prepared statement]. The first argument is the prepared statement 7726** object to be interrogated. The second argument 7727** is an integer code for a specific [SQLITE_STMTSTATUS counter] 7728** to be interrogated.)^ 7729** ^The current value of the requested counter is returned. 7730** ^If the resetFlg is true, then the counter is reset to zero after this 7731** interface call returns. 7732** 7733** See also: [sqlite3_status()] and [sqlite3_db_status()]. 7734*/ 7735int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 7736 7737/* 7738** CAPI3REF: Status Parameters for prepared statements 7739** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 7740** 7741** These preprocessor macros define integer codes that name counter 7742** values associated with the [sqlite3_stmt_status()] interface. 7743** The meanings of the various counters are as follows: 7744** 7745** <dl> 7746** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 7747** <dd>^This is the number of times that SQLite has stepped forward in 7748** a table as part of a full table scan. Large numbers for this counter 7749** may indicate opportunities for performance improvement through 7750** careful use of indices.</dd> 7751** 7752** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 7753** <dd>^This is the number of sort operations that have occurred. 7754** A non-zero value in this counter may indicate an opportunity to 7755** improvement performance through careful use of indices.</dd> 7756** 7757** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 7758** <dd>^This is the number of rows inserted into transient indices that 7759** were created automatically in order to help joins run faster. 7760** A non-zero value in this counter may indicate an opportunity to 7761** improvement performance by adding permanent indices that do not 7762** need to be reinitialized each time the statement is run.</dd> 7763** 7764** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 7765** <dd>^This is the number of virtual machine operations executed 7766** by the prepared statement if that number is less than or equal 7767** to 2147483647. The number of virtual machine operations can be 7768** used as a proxy for the total work done by the prepared statement. 7769** If the number of virtual machine operations exceeds 2147483647 7770** then the value returned by this statement status code is undefined. 7771** 7772** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 7773** <dd>^This is the number of times that the prepare statement has been 7774** automatically regenerated due to schema changes or change to 7775** [bound parameters] that might affect the query plan. 7776** 7777** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 7778** <dd>^This is the number of times that the prepared statement has 7779** been run. A single "run" for the purposes of this counter is one 7780** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 7781** The counter is incremented on the first [sqlite3_step()] call of each 7782** cycle. 7783** 7784** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 7785** <dd>^This is the approximate number of bytes of heap memory 7786** used to store the prepared statement. ^This value is not actually 7787** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 7788** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 7789** </dd> 7790** </dl> 7791*/ 7792#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 7793#define SQLITE_STMTSTATUS_SORT 2 7794#define SQLITE_STMTSTATUS_AUTOINDEX 3 7795#define SQLITE_STMTSTATUS_VM_STEP 4 7796#define SQLITE_STMTSTATUS_REPREPARE 5 7797#define SQLITE_STMTSTATUS_RUN 6 7798#define SQLITE_STMTSTATUS_MEMUSED 99 7799 7800/* 7801** CAPI3REF: Custom Page Cache Object 7802** 7803** The sqlite3_pcache type is opaque. It is implemented by 7804** the pluggable module. The SQLite core has no knowledge of 7805** its size or internal structure and never deals with the 7806** sqlite3_pcache object except by holding and passing pointers 7807** to the object. 7808** 7809** See [sqlite3_pcache_methods2] for additional information. 7810*/ 7811typedef struct sqlite3_pcache sqlite3_pcache; 7812 7813/* 7814** CAPI3REF: Custom Page Cache Object 7815** 7816** The sqlite3_pcache_page object represents a single page in the 7817** page cache. The page cache will allocate instances of this 7818** object. Various methods of the page cache use pointers to instances 7819** of this object as parameters or as their return value. 7820** 7821** See [sqlite3_pcache_methods2] for additional information. 7822*/ 7823typedef struct sqlite3_pcache_page sqlite3_pcache_page; 7824struct sqlite3_pcache_page { 7825 void *pBuf; /* The content of the page */ 7826 void *pExtra; /* Extra information associated with the page */ 7827}; 7828 7829/* 7830** CAPI3REF: Application Defined Page Cache. 7831** KEYWORDS: {page cache} 7832** 7833** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 7834** register an alternative page cache implementation by passing in an 7835** instance of the sqlite3_pcache_methods2 structure.)^ 7836** In many applications, most of the heap memory allocated by 7837** SQLite is used for the page cache. 7838** By implementing a 7839** custom page cache using this API, an application can better control 7840** the amount of memory consumed by SQLite, the way in which 7841** that memory is allocated and released, and the policies used to 7842** determine exactly which parts of a database file are cached and for 7843** how long. 7844** 7845** The alternative page cache mechanism is an 7846** extreme measure that is only needed by the most demanding applications. 7847** The built-in page cache is recommended for most uses. 7848** 7849** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 7850** internal buffer by SQLite within the call to [sqlite3_config]. Hence 7851** the application may discard the parameter after the call to 7852** [sqlite3_config()] returns.)^ 7853** 7854** [[the xInit() page cache method]] 7855** ^(The xInit() method is called once for each effective 7856** call to [sqlite3_initialize()])^ 7857** (usually only once during the lifetime of the process). ^(The xInit() 7858** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 7859** The intent of the xInit() method is to set up global data structures 7860** required by the custom page cache implementation. 7861** ^(If the xInit() method is NULL, then the 7862** built-in default page cache is used instead of the application defined 7863** page cache.)^ 7864** 7865** [[the xShutdown() page cache method]] 7866** ^The xShutdown() method is called by [sqlite3_shutdown()]. 7867** It can be used to clean up 7868** any outstanding resources before process shutdown, if required. 7869** ^The xShutdown() method may be NULL. 7870** 7871** ^SQLite automatically serializes calls to the xInit method, 7872** so the xInit method need not be threadsafe. ^The 7873** xShutdown method is only called from [sqlite3_shutdown()] so it does 7874** not need to be threadsafe either. All other methods must be threadsafe 7875** in multithreaded applications. 7876** 7877** ^SQLite will never invoke xInit() more than once without an intervening 7878** call to xShutdown(). 7879** 7880** [[the xCreate() page cache methods]] 7881** ^SQLite invokes the xCreate() method to construct a new cache instance. 7882** SQLite will typically create one cache instance for each open database file, 7883** though this is not guaranteed. ^The 7884** first parameter, szPage, is the size in bytes of the pages that must 7885** be allocated by the cache. ^szPage will always a power of two. ^The 7886** second parameter szExtra is a number of bytes of extra storage 7887** associated with each page cache entry. ^The szExtra parameter will 7888** a number less than 250. SQLite will use the 7889** extra szExtra bytes on each page to store metadata about the underlying 7890** database page on disk. The value passed into szExtra depends 7891** on the SQLite version, the target platform, and how SQLite was compiled. 7892** ^The third argument to xCreate(), bPurgeable, is true if the cache being 7893** created will be used to cache database pages of a file stored on disk, or 7894** false if it is used for an in-memory database. The cache implementation 7895** does not have to do anything special based with the value of bPurgeable; 7896** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 7897** never invoke xUnpin() except to deliberately delete a page. 7898** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 7899** false will always have the "discard" flag set to true. 7900** ^Hence, a cache created with bPurgeable false will 7901** never contain any unpinned pages. 7902** 7903** [[the xCachesize() page cache method]] 7904** ^(The xCachesize() method may be called at any time by SQLite to set the 7905** suggested maximum cache-size (number of pages stored by) the cache 7906** instance passed as the first argument. This is the value configured using 7907** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 7908** parameter, the implementation is not required to do anything with this 7909** value; it is advisory only. 7910** 7911** [[the xPagecount() page cache methods]] 7912** The xPagecount() method must return the number of pages currently 7913** stored in the cache, both pinned and unpinned. 7914** 7915** [[the xFetch() page cache methods]] 7916** The xFetch() method locates a page in the cache and returns a pointer to 7917** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 7918** The pBuf element of the returned sqlite3_pcache_page object will be a 7919** pointer to a buffer of szPage bytes used to store the content of a 7920** single database page. The pExtra element of sqlite3_pcache_page will be 7921** a pointer to the szExtra bytes of extra storage that SQLite has requested 7922** for each entry in the page cache. 7923** 7924** The page to be fetched is determined by the key. ^The minimum key value 7925** is 1. After it has been retrieved using xFetch, the page is considered 7926** to be "pinned". 7927** 7928** If the requested page is already in the page cache, then the page cache 7929** implementation must return a pointer to the page buffer with its content 7930** intact. If the requested page is not already in the cache, then the 7931** cache implementation should use the value of the createFlag 7932** parameter to help it determined what action to take: 7933** 7934** <table border=1 width=85% align=center> 7935** <tr><th> createFlag <th> Behavior when page is not already in cache 7936** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 7937** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 7938** Otherwise return NULL. 7939** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 7940** NULL if allocating a new page is effectively impossible. 7941** </table> 7942** 7943** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 7944** will only use a createFlag of 2 after a prior call with a createFlag of 1 7945** failed.)^ In between the to xFetch() calls, SQLite may 7946** attempt to unpin one or more cache pages by spilling the content of 7947** pinned pages to disk and synching the operating system disk cache. 7948** 7949** [[the xUnpin() page cache method]] 7950** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 7951** as its second argument. If the third parameter, discard, is non-zero, 7952** then the page must be evicted from the cache. 7953** ^If the discard parameter is 7954** zero, then the page may be discarded or retained at the discretion of 7955** page cache implementation. ^The page cache implementation 7956** may choose to evict unpinned pages at any time. 7957** 7958** The cache must not perform any reference counting. A single 7959** call to xUnpin() unpins the page regardless of the number of prior calls 7960** to xFetch(). 7961** 7962** [[the xRekey() page cache methods]] 7963** The xRekey() method is used to change the key value associated with the 7964** page passed as the second argument. If the cache 7965** previously contains an entry associated with newKey, it must be 7966** discarded. ^Any prior cache entry associated with newKey is guaranteed not 7967** to be pinned. 7968** 7969** When SQLite calls the xTruncate() method, the cache must discard all 7970** existing cache entries with page numbers (keys) greater than or equal 7971** to the value of the iLimit parameter passed to xTruncate(). If any 7972** of these pages are pinned, they are implicitly unpinned, meaning that 7973** they can be safely discarded. 7974** 7975** [[the xDestroy() page cache method]] 7976** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 7977** All resources associated with the specified cache should be freed. ^After 7978** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 7979** handle invalid, and will not use it with any other sqlite3_pcache_methods2 7980** functions. 7981** 7982** [[the xShrink() page cache method]] 7983** ^SQLite invokes the xShrink() method when it wants the page cache to 7984** free up as much of heap memory as possible. The page cache implementation 7985** is not obligated to free any memory, but well-behaved implementations should 7986** do their best. 7987*/ 7988typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 7989struct sqlite3_pcache_methods2 { 7990 int iVersion; 7991 void *pArg; 7992 int (*xInit)(void*); 7993 void (*xShutdown)(void*); 7994 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 7995 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7996 int (*xPagecount)(sqlite3_pcache*); 7997 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7998 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 7999 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 8000 unsigned oldKey, unsigned newKey); 8001 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8002 void (*xDestroy)(sqlite3_pcache*); 8003 void (*xShrink)(sqlite3_pcache*); 8004}; 8005 8006/* 8007** This is the obsolete pcache_methods object that has now been replaced 8008** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 8009** retained in the header file for backwards compatibility only. 8010*/ 8011typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 8012struct sqlite3_pcache_methods { 8013 void *pArg; 8014 int (*xInit)(void*); 8015 void (*xShutdown)(void*); 8016 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 8017 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8018 int (*xPagecount)(sqlite3_pcache*); 8019 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8020 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 8021 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 8022 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8023 void (*xDestroy)(sqlite3_pcache*); 8024}; 8025 8026 8027/* 8028** CAPI3REF: Online Backup Object 8029** 8030** The sqlite3_backup object records state information about an ongoing 8031** online backup operation. ^The sqlite3_backup object is created by 8032** a call to [sqlite3_backup_init()] and is destroyed by a call to 8033** [sqlite3_backup_finish()]. 8034** 8035** See Also: [Using the SQLite Online Backup API] 8036*/ 8037typedef struct sqlite3_backup sqlite3_backup; 8038 8039/* 8040** CAPI3REF: Online Backup API. 8041** 8042** The backup API copies the content of one database into another. 8043** It is useful either for creating backups of databases or 8044** for copying in-memory databases to or from persistent files. 8045** 8046** See Also: [Using the SQLite Online Backup API] 8047** 8048** ^SQLite holds a write transaction open on the destination database file 8049** for the duration of the backup operation. 8050** ^The source database is read-locked only while it is being read; 8051** it is not locked continuously for the entire backup operation. 8052** ^Thus, the backup may be performed on a live source database without 8053** preventing other database connections from 8054** reading or writing to the source database while the backup is underway. 8055** 8056** ^(To perform a backup operation: 8057** <ol> 8058** <li><b>sqlite3_backup_init()</b> is called once to initialize the 8059** backup, 8060** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 8061** the data between the two databases, and finally 8062** <li><b>sqlite3_backup_finish()</b> is called to release all resources 8063** associated with the backup operation. 8064** </ol>)^ 8065** There should be exactly one call to sqlite3_backup_finish() for each 8066** successful call to sqlite3_backup_init(). 8067** 8068** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 8069** 8070** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 8071** [database connection] associated with the destination database 8072** and the database name, respectively. 8073** ^The database name is "main" for the main database, "temp" for the 8074** temporary database, or the name specified after the AS keyword in 8075** an [ATTACH] statement for an attached database. 8076** ^The S and M arguments passed to 8077** sqlite3_backup_init(D,N,S,M) identify the [database connection] 8078** and database name of the source database, respectively. 8079** ^The source and destination [database connections] (parameters S and D) 8080** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 8081** an error. 8082** 8083** ^A call to sqlite3_backup_init() will fail, returning NULL, if 8084** there is already a read or read-write transaction open on the 8085** destination database. 8086** 8087** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 8088** returned and an error code and error message are stored in the 8089** destination [database connection] D. 8090** ^The error code and message for the failed call to sqlite3_backup_init() 8091** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 8092** [sqlite3_errmsg16()] functions. 8093** ^A successful call to sqlite3_backup_init() returns a pointer to an 8094** [sqlite3_backup] object. 8095** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 8096** sqlite3_backup_finish() functions to perform the specified backup 8097** operation. 8098** 8099** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 8100** 8101** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 8102** the source and destination databases specified by [sqlite3_backup] object B. 8103** ^If N is negative, all remaining source pages are copied. 8104** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 8105** are still more pages to be copied, then the function returns [SQLITE_OK]. 8106** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 8107** from source to destination, then it returns [SQLITE_DONE]. 8108** ^If an error occurs while running sqlite3_backup_step(B,N), 8109** then an [error code] is returned. ^As well as [SQLITE_OK] and 8110** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 8111** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 8112** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 8113** 8114** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 8115** <ol> 8116** <li> the destination database was opened read-only, or 8117** <li> the destination database is using write-ahead-log journaling 8118** and the destination and source page sizes differ, or 8119** <li> the destination database is an in-memory database and the 8120** destination and source page sizes differ. 8121** </ol>)^ 8122** 8123** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 8124** the [sqlite3_busy_handler | busy-handler function] 8125** is invoked (if one is specified). ^If the 8126** busy-handler returns non-zero before the lock is available, then 8127** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 8128** sqlite3_backup_step() can be retried later. ^If the source 8129** [database connection] 8130** is being used to write to the source database when sqlite3_backup_step() 8131** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 8132** case the call to sqlite3_backup_step() can be retried later on. ^(If 8133** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 8134** [SQLITE_READONLY] is returned, then 8135** there is no point in retrying the call to sqlite3_backup_step(). These 8136** errors are considered fatal.)^ The application must accept 8137** that the backup operation has failed and pass the backup operation handle 8138** to the sqlite3_backup_finish() to release associated resources. 8139** 8140** ^The first call to sqlite3_backup_step() obtains an exclusive lock 8141** on the destination file. ^The exclusive lock is not released until either 8142** sqlite3_backup_finish() is called or the backup operation is complete 8143** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 8144** sqlite3_backup_step() obtains a [shared lock] on the source database that 8145** lasts for the duration of the sqlite3_backup_step() call. 8146** ^Because the source database is not locked between calls to 8147** sqlite3_backup_step(), the source database may be modified mid-way 8148** through the backup process. ^If the source database is modified by an 8149** external process or via a database connection other than the one being 8150** used by the backup operation, then the backup will be automatically 8151** restarted by the next call to sqlite3_backup_step(). ^If the source 8152** database is modified by the using the same database connection as is used 8153** by the backup operation, then the backup database is automatically 8154** updated at the same time. 8155** 8156** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 8157** 8158** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 8159** application wishes to abandon the backup operation, the application 8160** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 8161** ^The sqlite3_backup_finish() interfaces releases all 8162** resources associated with the [sqlite3_backup] object. 8163** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 8164** active write-transaction on the destination database is rolled back. 8165** The [sqlite3_backup] object is invalid 8166** and may not be used following a call to sqlite3_backup_finish(). 8167** 8168** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 8169** sqlite3_backup_step() errors occurred, regardless or whether or not 8170** sqlite3_backup_step() completed. 8171** ^If an out-of-memory condition or IO error occurred during any prior 8172** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 8173** sqlite3_backup_finish() returns the corresponding [error code]. 8174** 8175** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 8176** is not a permanent error and does not affect the return value of 8177** sqlite3_backup_finish(). 8178** 8179** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 8180** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 8181** 8182** ^The sqlite3_backup_remaining() routine returns the number of pages still 8183** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 8184** ^The sqlite3_backup_pagecount() routine returns the total number of pages 8185** in the source database at the conclusion of the most recent 8186** sqlite3_backup_step(). 8187** ^(The values returned by these functions are only updated by 8188** sqlite3_backup_step(). If the source database is modified in a way that 8189** changes the size of the source database or the number of pages remaining, 8190** those changes are not reflected in the output of sqlite3_backup_pagecount() 8191** and sqlite3_backup_remaining() until after the next 8192** sqlite3_backup_step().)^ 8193** 8194** <b>Concurrent Usage of Database Handles</b> 8195** 8196** ^The source [database connection] may be used by the application for other 8197** purposes while a backup operation is underway or being initialized. 8198** ^If SQLite is compiled and configured to support threadsafe database 8199** connections, then the source database connection may be used concurrently 8200** from within other threads. 8201** 8202** However, the application must guarantee that the destination 8203** [database connection] is not passed to any other API (by any thread) after 8204** sqlite3_backup_init() is called and before the corresponding call to 8205** sqlite3_backup_finish(). SQLite does not currently check to see 8206** if the application incorrectly accesses the destination [database connection] 8207** and so no error code is reported, but the operations may malfunction 8208** nevertheless. Use of the destination database connection while a 8209** backup is in progress might also also cause a mutex deadlock. 8210** 8211** If running in [shared cache mode], the application must 8212** guarantee that the shared cache used by the destination database 8213** is not accessed while the backup is running. In practice this means 8214** that the application must guarantee that the disk file being 8215** backed up to is not accessed by any connection within the process, 8216** not just the specific connection that was passed to sqlite3_backup_init(). 8217** 8218** The [sqlite3_backup] object itself is partially threadsafe. Multiple 8219** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 8220** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 8221** APIs are not strictly speaking threadsafe. If they are invoked at the 8222** same time as another thread is invoking sqlite3_backup_step() it is 8223** possible that they return invalid values. 8224*/ 8225sqlite3_backup *sqlite3_backup_init( 8226 sqlite3 *pDest, /* Destination database handle */ 8227 const char *zDestName, /* Destination database name */ 8228 sqlite3 *pSource, /* Source database handle */ 8229 const char *zSourceName /* Source database name */ 8230); 8231int sqlite3_backup_step(sqlite3_backup *p, int nPage); 8232int sqlite3_backup_finish(sqlite3_backup *p); 8233int sqlite3_backup_remaining(sqlite3_backup *p); 8234int sqlite3_backup_pagecount(sqlite3_backup *p); 8235 8236/* 8237** CAPI3REF: Unlock Notification 8238** METHOD: sqlite3 8239** 8240** ^When running in shared-cache mode, a database operation may fail with 8241** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 8242** individual tables within the shared-cache cannot be obtained. See 8243** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 8244** ^This API may be used to register a callback that SQLite will invoke 8245** when the connection currently holding the required lock relinquishes it. 8246** ^This API is only available if the library was compiled with the 8247** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 8248** 8249** See Also: [Using the SQLite Unlock Notification Feature]. 8250** 8251** ^Shared-cache locks are released when a database connection concludes 8252** its current transaction, either by committing it or rolling it back. 8253** 8254** ^When a connection (known as the blocked connection) fails to obtain a 8255** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 8256** identity of the database connection (the blocking connection) that 8257** has locked the required resource is stored internally. ^After an 8258** application receives an SQLITE_LOCKED error, it may call the 8259** sqlite3_unlock_notify() method with the blocked connection handle as 8260** the first argument to register for a callback that will be invoked 8261** when the blocking connections current transaction is concluded. ^The 8262** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 8263** call that concludes the blocking connections transaction. 8264** 8265** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 8266** there is a chance that the blocking connection will have already 8267** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 8268** If this happens, then the specified callback is invoked immediately, 8269** from within the call to sqlite3_unlock_notify().)^ 8270** 8271** ^If the blocked connection is attempting to obtain a write-lock on a 8272** shared-cache table, and more than one other connection currently holds 8273** a read-lock on the same table, then SQLite arbitrarily selects one of 8274** the other connections to use as the blocking connection. 8275** 8276** ^(There may be at most one unlock-notify callback registered by a 8277** blocked connection. If sqlite3_unlock_notify() is called when the 8278** blocked connection already has a registered unlock-notify callback, 8279** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 8280** called with a NULL pointer as its second argument, then any existing 8281** unlock-notify callback is canceled. ^The blocked connections 8282** unlock-notify callback may also be canceled by closing the blocked 8283** connection using [sqlite3_close()]. 8284** 8285** The unlock-notify callback is not reentrant. If an application invokes 8286** any sqlite3_xxx API functions from within an unlock-notify callback, a 8287** crash or deadlock may be the result. 8288** 8289** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 8290** returns SQLITE_OK. 8291** 8292** <b>Callback Invocation Details</b> 8293** 8294** When an unlock-notify callback is registered, the application provides a 8295** single void* pointer that is passed to the callback when it is invoked. 8296** However, the signature of the callback function allows SQLite to pass 8297** it an array of void* context pointers. The first argument passed to 8298** an unlock-notify callback is a pointer to an array of void* pointers, 8299** and the second is the number of entries in the array. 8300** 8301** When a blocking connections transaction is concluded, there may be 8302** more than one blocked connection that has registered for an unlock-notify 8303** callback. ^If two or more such blocked connections have specified the 8304** same callback function, then instead of invoking the callback function 8305** multiple times, it is invoked once with the set of void* context pointers 8306** specified by the blocked connections bundled together into an array. 8307** This gives the application an opportunity to prioritize any actions 8308** related to the set of unblocked database connections. 8309** 8310** <b>Deadlock Detection</b> 8311** 8312** Assuming that after registering for an unlock-notify callback a 8313** database waits for the callback to be issued before taking any further 8314** action (a reasonable assumption), then using this API may cause the 8315** application to deadlock. For example, if connection X is waiting for 8316** connection Y's transaction to be concluded, and similarly connection 8317** Y is waiting on connection X's transaction, then neither connection 8318** will proceed and the system may remain deadlocked indefinitely. 8319** 8320** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 8321** detection. ^If a given call to sqlite3_unlock_notify() would put the 8322** system in a deadlocked state, then SQLITE_LOCKED is returned and no 8323** unlock-notify callback is registered. The system is said to be in 8324** a deadlocked state if connection A has registered for an unlock-notify 8325** callback on the conclusion of connection B's transaction, and connection 8326** B has itself registered for an unlock-notify callback when connection 8327** A's transaction is concluded. ^Indirect deadlock is also detected, so 8328** the system is also considered to be deadlocked if connection B has 8329** registered for an unlock-notify callback on the conclusion of connection 8330** C's transaction, where connection C is waiting on connection A. ^Any 8331** number of levels of indirection are allowed. 8332** 8333** <b>The "DROP TABLE" Exception</b> 8334** 8335** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 8336** always appropriate to call sqlite3_unlock_notify(). There is however, 8337** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 8338** SQLite checks if there are any currently executing SELECT statements 8339** that belong to the same connection. If there are, SQLITE_LOCKED is 8340** returned. In this case there is no "blocking connection", so invoking 8341** sqlite3_unlock_notify() results in the unlock-notify callback being 8342** invoked immediately. If the application then re-attempts the "DROP TABLE" 8343** or "DROP INDEX" query, an infinite loop might be the result. 8344** 8345** One way around this problem is to check the extended error code returned 8346** by an sqlite3_step() call. ^(If there is a blocking connection, then the 8347** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 8348** the special "DROP TABLE/INDEX" case, the extended error code is just 8349** SQLITE_LOCKED.)^ 8350*/ 8351int sqlite3_unlock_notify( 8352 sqlite3 *pBlocked, /* Waiting connection */ 8353 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 8354 void *pNotifyArg /* Argument to pass to xNotify */ 8355); 8356 8357 8358/* 8359** CAPI3REF: String Comparison 8360** 8361** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 8362** and extensions to compare the contents of two buffers containing UTF-8 8363** strings in a case-independent fashion, using the same definition of "case 8364** independence" that SQLite uses internally when comparing identifiers. 8365*/ 8366int sqlite3_stricmp(const char *, const char *); 8367int sqlite3_strnicmp(const char *, const char *, int); 8368 8369/* 8370** CAPI3REF: String Globbing 8371* 8372** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 8373** string X matches the [GLOB] pattern P. 8374** ^The definition of [GLOB] pattern matching used in 8375** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 8376** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 8377** is case sensitive. 8378** 8379** Note that this routine returns zero on a match and non-zero if the strings 8380** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8381** 8382** See also: [sqlite3_strlike()]. 8383*/ 8384int sqlite3_strglob(const char *zGlob, const char *zStr); 8385 8386/* 8387** CAPI3REF: String LIKE Matching 8388* 8389** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 8390** string X matches the [LIKE] pattern P with escape character E. 8391** ^The definition of [LIKE] pattern matching used in 8392** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 8393** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 8394** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 8395** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 8396** insensitive - equivalent upper and lower case ASCII characters match 8397** one another. 8398** 8399** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 8400** only ASCII characters are case folded. 8401** 8402** Note that this routine returns zero on a match and non-zero if the strings 8403** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8404** 8405** See also: [sqlite3_strglob()]. 8406*/ 8407int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 8408 8409/* 8410** CAPI3REF: Error Logging Interface 8411** 8412** ^The [sqlite3_log()] interface writes a message into the [error log] 8413** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 8414** ^If logging is enabled, the zFormat string and subsequent arguments are 8415** used with [sqlite3_snprintf()] to generate the final output string. 8416** 8417** The sqlite3_log() interface is intended for use by extensions such as 8418** virtual tables, collating functions, and SQL functions. While there is 8419** nothing to prevent an application from calling sqlite3_log(), doing so 8420** is considered bad form. 8421** 8422** The zFormat string must not be NULL. 8423** 8424** To avoid deadlocks and other threading problems, the sqlite3_log() routine 8425** will not use dynamically allocated memory. The log message is stored in 8426** a fixed-length buffer on the stack. If the log message is longer than 8427** a few hundred characters, it will be truncated to the length of the 8428** buffer. 8429*/ 8430void sqlite3_log(int iErrCode, const char *zFormat, ...); 8431 8432/* 8433** CAPI3REF: Write-Ahead Log Commit Hook 8434** METHOD: sqlite3 8435** 8436** ^The [sqlite3_wal_hook()] function is used to register a callback that 8437** is invoked each time data is committed to a database in wal mode. 8438** 8439** ^(The callback is invoked by SQLite after the commit has taken place and 8440** the associated write-lock on the database released)^, so the implementation 8441** may read, write or [checkpoint] the database as required. 8442** 8443** ^The first parameter passed to the callback function when it is invoked 8444** is a copy of the third parameter passed to sqlite3_wal_hook() when 8445** registering the callback. ^The second is a copy of the database handle. 8446** ^The third parameter is the name of the database that was written to - 8447** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 8448** is the number of pages currently in the write-ahead log file, 8449** including those that were just committed. 8450** 8451** The callback function should normally return [SQLITE_OK]. ^If an error 8452** code is returned, that error will propagate back up through the 8453** SQLite code base to cause the statement that provoked the callback 8454** to report an error, though the commit will have still occurred. If the 8455** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 8456** that does not correspond to any valid SQLite error code, the results 8457** are undefined. 8458** 8459** A single database handle may have at most a single write-ahead log callback 8460** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 8461** previously registered write-ahead log callback. ^Note that the 8462** [sqlite3_wal_autocheckpoint()] interface and the 8463** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 8464** overwrite any prior [sqlite3_wal_hook()] settings. 8465*/ 8466void *sqlite3_wal_hook( 8467 sqlite3*, 8468 int(*)(void *,sqlite3*,const char*,int), 8469 void* 8470); 8471 8472/* 8473** CAPI3REF: Configure an auto-checkpoint 8474** METHOD: sqlite3 8475** 8476** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 8477** [sqlite3_wal_hook()] that causes any database on [database connection] D 8478** to automatically [checkpoint] 8479** after committing a transaction if there are N or 8480** more frames in the [write-ahead log] file. ^Passing zero or 8481** a negative value as the nFrame parameter disables automatic 8482** checkpoints entirely. 8483** 8484** ^The callback registered by this function replaces any existing callback 8485** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 8486** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 8487** configured by this function. 8488** 8489** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 8490** from SQL. 8491** 8492** ^Checkpoints initiated by this mechanism are 8493** [sqlite3_wal_checkpoint_v2|PASSIVE]. 8494** 8495** ^Every new [database connection] defaults to having the auto-checkpoint 8496** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 8497** pages. The use of this interface 8498** is only necessary if the default setting is found to be suboptimal 8499** for a particular application. 8500*/ 8501int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 8502 8503/* 8504** CAPI3REF: Checkpoint a database 8505** METHOD: sqlite3 8506** 8507** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 8508** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 8509** 8510** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 8511** [write-ahead log] for database X on [database connection] D to be 8512** transferred into the database file and for the write-ahead log to 8513** be reset. See the [checkpointing] documentation for addition 8514** information. 8515** 8516** This interface used to be the only way to cause a checkpoint to 8517** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 8518** interface was added. This interface is retained for backwards 8519** compatibility and as a convenience for applications that need to manually 8520** start a callback but which do not need the full power (and corresponding 8521** complication) of [sqlite3_wal_checkpoint_v2()]. 8522*/ 8523int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 8524 8525/* 8526** CAPI3REF: Checkpoint a database 8527** METHOD: sqlite3 8528** 8529** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 8530** operation on database X of [database connection] D in mode M. Status 8531** information is written back into integers pointed to by L and C.)^ 8532** ^(The M parameter must be a valid [checkpoint mode]:)^ 8533** 8534** <dl> 8535** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 8536** ^Checkpoint as many frames as possible without waiting for any database 8537** readers or writers to finish, then sync the database file if all frames 8538** in the log were checkpointed. ^The [busy-handler callback] 8539** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 8540** ^On the other hand, passive mode might leave the checkpoint unfinished 8541** if there are concurrent readers or writers. 8542** 8543** <dt>SQLITE_CHECKPOINT_FULL<dd> 8544** ^This mode blocks (it invokes the 8545** [sqlite3_busy_handler|busy-handler callback]) until there is no 8546** database writer and all readers are reading from the most recent database 8547** snapshot. ^It then checkpoints all frames in the log file and syncs the 8548** database file. ^This mode blocks new database writers while it is pending, 8549** but new database readers are allowed to continue unimpeded. 8550** 8551** <dt>SQLITE_CHECKPOINT_RESTART<dd> 8552** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 8553** that after checkpointing the log file it blocks (calls the 8554** [busy-handler callback]) 8555** until all readers are reading from the database file only. ^This ensures 8556** that the next writer will restart the log file from the beginning. 8557** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 8558** database writer attempts while it is pending, but does not impede readers. 8559** 8560** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 8561** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 8562** addition that it also truncates the log file to zero bytes just prior 8563** to a successful return. 8564** </dl> 8565** 8566** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 8567** the log file or to -1 if the checkpoint could not run because 8568** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 8569** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 8570** log file (including any that were already checkpointed before the function 8571** was called) or to -1 if the checkpoint could not run due to an error or 8572** because the database is not in WAL mode. ^Note that upon successful 8573** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 8574** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 8575** 8576** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 8577** any other process is running a checkpoint operation at the same time, the 8578** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 8579** busy-handler configured, it will not be invoked in this case. 8580** 8581** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 8582** exclusive "writer" lock on the database file. ^If the writer lock cannot be 8583** obtained immediately, and a busy-handler is configured, it is invoked and 8584** the writer lock retried until either the busy-handler returns 0 or the lock 8585** is successfully obtained. ^The busy-handler is also invoked while waiting for 8586** database readers as described above. ^If the busy-handler returns 0 before 8587** the writer lock is obtained or while waiting for database readers, the 8588** checkpoint operation proceeds from that point in the same way as 8589** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 8590** without blocking any further. ^SQLITE_BUSY is returned in this case. 8591** 8592** ^If parameter zDb is NULL or points to a zero length string, then the 8593** specified operation is attempted on all WAL databases [attached] to 8594** [database connection] db. In this case the 8595** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 8596** an SQLITE_BUSY error is encountered when processing one or more of the 8597** attached WAL databases, the operation is still attempted on any remaining 8598** attached databases and SQLITE_BUSY is returned at the end. ^If any other 8599** error occurs while processing an attached database, processing is abandoned 8600** and the error code is returned to the caller immediately. ^If no error 8601** (SQLITE_BUSY or otherwise) is encountered while processing the attached 8602** databases, SQLITE_OK is returned. 8603** 8604** ^If database zDb is the name of an attached database that is not in WAL 8605** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 8606** zDb is not NULL (or a zero length string) and is not the name of any 8607** attached database, SQLITE_ERROR is returned to the caller. 8608** 8609** ^Unless it returns SQLITE_MISUSE, 8610** the sqlite3_wal_checkpoint_v2() interface 8611** sets the error information that is queried by 8612** [sqlite3_errcode()] and [sqlite3_errmsg()]. 8613** 8614** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 8615** from SQL. 8616*/ 8617int sqlite3_wal_checkpoint_v2( 8618 sqlite3 *db, /* Database handle */ 8619 const char *zDb, /* Name of attached database (or NULL) */ 8620 int eMode, /* SQLITE_CHECKPOINT_* value */ 8621 int *pnLog, /* OUT: Size of WAL log in frames */ 8622 int *pnCkpt /* OUT: Total number of frames checkpointed */ 8623); 8624 8625/* 8626** CAPI3REF: Checkpoint Mode Values 8627** KEYWORDS: {checkpoint mode} 8628** 8629** These constants define all valid values for the "checkpoint mode" passed 8630** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 8631** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 8632** meaning of each of these checkpoint modes. 8633*/ 8634#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 8635#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 8636#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 8637#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 8638 8639/* 8640** CAPI3REF: Virtual Table Interface Configuration 8641** 8642** This function may be called by either the [xConnect] or [xCreate] method 8643** of a [virtual table] implementation to configure 8644** various facets of the virtual table interface. 8645** 8646** If this interface is invoked outside the context of an xConnect or 8647** xCreate virtual table method then the behavior is undefined. 8648** 8649** At present, there is only one option that may be configured using 8650** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 8651** may be added in the future. 8652*/ 8653int sqlite3_vtab_config(sqlite3*, int op, ...); 8654 8655/* 8656** CAPI3REF: Virtual Table Configuration Options 8657** 8658** These macros define the various options to the 8659** [sqlite3_vtab_config()] interface that [virtual table] implementations 8660** can use to customize and optimize their behavior. 8661** 8662** <dl> 8663** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]] 8664** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 8665** <dd>Calls of the form 8666** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 8667** where X is an integer. If X is zero, then the [virtual table] whose 8668** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 8669** support constraints. In this configuration (which is the default) if 8670** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 8671** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 8672** specified as part of the users SQL statement, regardless of the actual 8673** ON CONFLICT mode specified. 8674** 8675** If X is non-zero, then the virtual table implementation guarantees 8676** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 8677** any modifications to internal or persistent data structures have been made. 8678** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 8679** is able to roll back a statement or database transaction, and abandon 8680** or continue processing the current SQL statement as appropriate. 8681** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 8682** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 8683** had been ABORT. 8684** 8685** Virtual table implementations that are required to handle OR REPLACE 8686** must do so within the [xUpdate] method. If a call to the 8687** [sqlite3_vtab_on_conflict()] function indicates that the current ON 8688** CONFLICT policy is REPLACE, the virtual table implementation should 8689** silently replace the appropriate rows within the xUpdate callback and 8690** return SQLITE_OK. Or, if this is not possible, it may return 8691** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 8692** constraint handling. 8693** </dl> 8694*/ 8695#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 8696 8697/* 8698** CAPI3REF: Determine The Virtual Table Conflict Policy 8699** 8700** This function may only be called from within a call to the [xUpdate] method 8701** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 8702** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 8703** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 8704** of the SQL statement that triggered the call to the [xUpdate] method of the 8705** [virtual table]. 8706*/ 8707int sqlite3_vtab_on_conflict(sqlite3 *); 8708 8709/* 8710** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE 8711** 8712** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn] 8713** method of a [virtual table], then it returns true if and only if the 8714** column is being fetched as part of an UPDATE operation during which the 8715** column value will not change. Applications might use this to substitute 8716** a return value that is less expensive to compute and that the corresponding 8717** [xUpdate] method understands as a "no-change" value. 8718** 8719** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that 8720** the column is not changed by the UPDATE statement, then the xColumn 8721** method can optionally return without setting a result, without calling 8722** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces]. 8723** In that case, [sqlite3_value_nochange(X)] will return true for the 8724** same column in the [xUpdate] method. 8725*/ 8726int sqlite3_vtab_nochange(sqlite3_context*); 8727 8728/* 8729** CAPI3REF: Determine The Collation For a Virtual Table Constraint 8730** 8731** This function may only be called from within a call to the [xBestIndex] 8732** method of a [virtual table]. 8733** 8734** The first argument must be the sqlite3_index_info object that is the 8735** first parameter to the xBestIndex() method. The second argument must be 8736** an index into the aConstraint[] array belonging to the sqlite3_index_info 8737** structure passed to xBestIndex. This function returns a pointer to a buffer 8738** containing the name of the collation sequence for the corresponding 8739** constraint. 8740*/ 8741SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int); 8742 8743/* 8744** CAPI3REF: Conflict resolution modes 8745** KEYWORDS: {conflict resolution mode} 8746** 8747** These constants are returned by [sqlite3_vtab_on_conflict()] to 8748** inform a [virtual table] implementation what the [ON CONFLICT] mode 8749** is for the SQL statement being evaluated. 8750** 8751** Note that the [SQLITE_IGNORE] constant is also used as a potential 8752** return value from the [sqlite3_set_authorizer()] callback and that 8753** [SQLITE_ABORT] is also a [result code]. 8754*/ 8755#define SQLITE_ROLLBACK 1 8756/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 8757#define SQLITE_FAIL 3 8758/* #define SQLITE_ABORT 4 // Also an error code */ 8759#define SQLITE_REPLACE 5 8760 8761/* 8762** CAPI3REF: Prepared Statement Scan Status Opcodes 8763** KEYWORDS: {scanstatus options} 8764** 8765** The following constants can be used for the T parameter to the 8766** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 8767** different metric for sqlite3_stmt_scanstatus() to return. 8768** 8769** When the value returned to V is a string, space to hold that string is 8770** managed by the prepared statement S and will be automatically freed when 8771** S is finalized. 8772** 8773** <dl> 8774** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 8775** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 8776** set to the total number of times that the X-th loop has run.</dd> 8777** 8778** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 8779** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 8780** to the total number of rows examined by all iterations of the X-th loop.</dd> 8781** 8782** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 8783** <dd>^The "double" variable pointed to by the T parameter will be set to the 8784** query planner's estimate for the average number of rows output from each 8785** iteration of the X-th loop. If the query planner's estimates was accurate, 8786** then this value will approximate the quotient NVISIT/NLOOP and the 8787** product of this value for all prior loops with the same SELECTID will 8788** be the NLOOP value for the current loop. 8789** 8790** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 8791** <dd>^The "const char *" variable pointed to by the T parameter will be set 8792** to a zero-terminated UTF-8 string containing the name of the index or table 8793** used for the X-th loop. 8794** 8795** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 8796** <dd>^The "const char *" variable pointed to by the T parameter will be set 8797** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 8798** description for the X-th loop. 8799** 8800** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 8801** <dd>^The "int" variable pointed to by the T parameter will be set to the 8802** "select-id" for the X-th loop. The select-id identifies which query or 8803** subquery the loop is part of. The main query has a select-id of zero. 8804** The select-id is the same value as is output in the first column 8805** of an [EXPLAIN QUERY PLAN] query. 8806** </dl> 8807*/ 8808#define SQLITE_SCANSTAT_NLOOP 0 8809#define SQLITE_SCANSTAT_NVISIT 1 8810#define SQLITE_SCANSTAT_EST 2 8811#define SQLITE_SCANSTAT_NAME 3 8812#define SQLITE_SCANSTAT_EXPLAIN 4 8813#define SQLITE_SCANSTAT_SELECTID 5 8814 8815/* 8816** CAPI3REF: Prepared Statement Scan Status 8817** METHOD: sqlite3_stmt 8818** 8819** This interface returns information about the predicted and measured 8820** performance for pStmt. Advanced applications can use this 8821** interface to compare the predicted and the measured performance and 8822** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 8823** 8824** Since this interface is expected to be rarely used, it is only 8825** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 8826** compile-time option. 8827** 8828** The "iScanStatusOp" parameter determines which status information to return. 8829** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 8830** of this interface is undefined. 8831** ^The requested measurement is written into a variable pointed to by 8832** the "pOut" parameter. 8833** Parameter "idx" identifies the specific loop to retrieve statistics for. 8834** Loops are numbered starting from zero. ^If idx is out of range - less than 8835** zero or greater than or equal to the total number of loops used to implement 8836** the statement - a non-zero value is returned and the variable that pOut 8837** points to is unchanged. 8838** 8839** ^Statistics might not be available for all loops in all statements. ^In cases 8840** where there exist loops with no available statistics, this function behaves 8841** as if the loop did not exist - it returns non-zero and leave the variable 8842** that pOut points to unchanged. 8843** 8844** See also: [sqlite3_stmt_scanstatus_reset()] 8845*/ 8846int sqlite3_stmt_scanstatus( 8847 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 8848 int idx, /* Index of loop to report on */ 8849 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 8850 void *pOut /* Result written here */ 8851); 8852 8853/* 8854** CAPI3REF: Zero Scan-Status Counters 8855** METHOD: sqlite3_stmt 8856** 8857** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 8858** 8859** This API is only available if the library is built with pre-processor 8860** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 8861*/ 8862void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 8863 8864/* 8865** CAPI3REF: Flush caches to disk mid-transaction 8866** 8867** ^If a write-transaction is open on [database connection] D when the 8868** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 8869** pages in the pager-cache that are not currently in use are written out 8870** to disk. A dirty page may be in use if a database cursor created by an 8871** active SQL statement is reading from it, or if it is page 1 of a database 8872** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 8873** interface flushes caches for all schemas - "main", "temp", and 8874** any [attached] databases. 8875** 8876** ^If this function needs to obtain extra database locks before dirty pages 8877** can be flushed to disk, it does so. ^If those locks cannot be obtained 8878** immediately and there is a busy-handler callback configured, it is invoked 8879** in the usual manner. ^If the required lock still cannot be obtained, then 8880** the database is skipped and an attempt made to flush any dirty pages 8881** belonging to the next (if any) database. ^If any databases are skipped 8882** because locks cannot be obtained, but no other error occurs, this 8883** function returns SQLITE_BUSY. 8884** 8885** ^If any other error occurs while flushing dirty pages to disk (for 8886** example an IO error or out-of-memory condition), then processing is 8887** abandoned and an SQLite [error code] is returned to the caller immediately. 8888** 8889** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 8890** 8891** ^This function does not set the database handle error code or message 8892** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 8893*/ 8894int sqlite3_db_cacheflush(sqlite3*); 8895 8896/* 8897** CAPI3REF: The pre-update hook. 8898** 8899** ^These interfaces are only available if SQLite is compiled using the 8900** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 8901** 8902** ^The [sqlite3_preupdate_hook()] interface registers a callback function 8903** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 8904** on a database table. 8905** ^At most one preupdate hook may be registered at a time on a single 8906** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 8907** the previous setting. 8908** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 8909** with a NULL pointer as the second parameter. 8910** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 8911** the first parameter to callbacks. 8912** 8913** ^The preupdate hook only fires for changes to real database tables; the 8914** preupdate hook is not invoked for changes to [virtual tables] or to 8915** system tables like sqlite_master or sqlite_stat1. 8916** 8917** ^The second parameter to the preupdate callback is a pointer to 8918** the [database connection] that registered the preupdate hook. 8919** ^The third parameter to the preupdate callback is one of the constants 8920** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 8921** kind of update operation that is about to occur. 8922** ^(The fourth parameter to the preupdate callback is the name of the 8923** database within the database connection that is being modified. This 8924** will be "main" for the main database or "temp" for TEMP tables or 8925** the name given after the AS keyword in the [ATTACH] statement for attached 8926** databases.)^ 8927** ^The fifth parameter to the preupdate callback is the name of the 8928** table that is being modified. 8929** 8930** For an UPDATE or DELETE operation on a [rowid table], the sixth 8931** parameter passed to the preupdate callback is the initial [rowid] of the 8932** row being modified or deleted. For an INSERT operation on a rowid table, 8933** or any operation on a WITHOUT ROWID table, the value of the sixth 8934** parameter is undefined. For an INSERT or UPDATE on a rowid table the 8935** seventh parameter is the final rowid value of the row being inserted 8936** or updated. The value of the seventh parameter passed to the callback 8937** function is not defined for operations on WITHOUT ROWID tables, or for 8938** INSERT operations on rowid tables. 8939** 8940** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 8941** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 8942** provide additional information about a preupdate event. These routines 8943** may only be called from within a preupdate callback. Invoking any of 8944** these routines from outside of a preupdate callback or with a 8945** [database connection] pointer that is different from the one supplied 8946** to the preupdate callback results in undefined and probably undesirable 8947** behavior. 8948** 8949** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 8950** in the row that is being inserted, updated, or deleted. 8951** 8952** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 8953** a [protected sqlite3_value] that contains the value of the Nth column of 8954** the table row before it is updated. The N parameter must be between 0 8955** and one less than the number of columns or the behavior will be 8956** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 8957** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 8958** behavior is undefined. The [sqlite3_value] that P points to 8959** will be destroyed when the preupdate callback returns. 8960** 8961** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 8962** a [protected sqlite3_value] that contains the value of the Nth column of 8963** the table row after it is updated. The N parameter must be between 0 8964** and one less than the number of columns or the behavior will be 8965** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 8966** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 8967** behavior is undefined. The [sqlite3_value] that P points to 8968** will be destroyed when the preupdate callback returns. 8969** 8970** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 8971** callback was invoked as a result of a direct insert, update, or delete 8972** operation; or 1 for inserts, updates, or deletes invoked by top-level 8973** triggers; or 2 for changes resulting from triggers called by top-level 8974** triggers; and so forth. 8975** 8976** See also: [sqlite3_update_hook()] 8977*/ 8978#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 8979void *sqlite3_preupdate_hook( 8980 sqlite3 *db, 8981 void(*xPreUpdate)( 8982 void *pCtx, /* Copy of third arg to preupdate_hook() */ 8983 sqlite3 *db, /* Database handle */ 8984 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 8985 char const *zDb, /* Database name */ 8986 char const *zName, /* Table name */ 8987 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 8988 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 8989 ), 8990 void* 8991); 8992int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 8993int sqlite3_preupdate_count(sqlite3 *); 8994int sqlite3_preupdate_depth(sqlite3 *); 8995int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 8996#endif 8997 8998/* 8999** CAPI3REF: Low-level system error code 9000** 9001** ^Attempt to return the underlying operating system error code or error 9002** number that caused the most recent I/O error or failure to open a file. 9003** The return value is OS-dependent. For example, on unix systems, after 9004** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 9005** called to get back the underlying "errno" that caused the problem, such 9006** as ENOSPC, EAUTH, EISDIR, and so forth. 9007*/ 9008int sqlite3_system_errno(sqlite3*); 9009 9010/* 9011** CAPI3REF: Database Snapshot 9012** KEYWORDS: {snapshot} {sqlite3_snapshot} 9013** 9014** An instance of the snapshot object records the state of a [WAL mode] 9015** database for some specific point in history. 9016** 9017** In [WAL mode], multiple [database connections] that are open on the 9018** same database file can each be reading a different historical version 9019** of the database file. When a [database connection] begins a read 9020** transaction, that connection sees an unchanging copy of the database 9021** as it existed for the point in time when the transaction first started. 9022** Subsequent changes to the database from other connections are not seen 9023** by the reader until a new read transaction is started. 9024** 9025** The sqlite3_snapshot object records state information about an historical 9026** version of the database file so that it is possible to later open a new read 9027** transaction that sees that historical version of the database rather than 9028** the most recent version. 9029*/ 9030typedef struct sqlite3_snapshot { 9031 unsigned char hidden[48]; 9032} sqlite3_snapshot; 9033 9034/* 9035** CAPI3REF: Record A Database Snapshot 9036** CONSTRUCTOR: sqlite3_snapshot 9037** 9038** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 9039** new [sqlite3_snapshot] object that records the current state of 9040** schema S in database connection D. ^On success, the 9041** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 9042** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 9043** If there is not already a read-transaction open on schema S when 9044** this function is called, one is opened automatically. 9045** 9046** The following must be true for this function to succeed. If any of 9047** the following statements are false when sqlite3_snapshot_get() is 9048** called, SQLITE_ERROR is returned. The final value of *P is undefined 9049** in this case. 9050** 9051** <ul> 9052** <li> The database handle must not be in [autocommit mode]. 9053** 9054** <li> Schema S of [database connection] D must be a [WAL mode] database. 9055** 9056** <li> There must not be a write transaction open on schema S of database 9057** connection D. 9058** 9059** <li> One or more transactions must have been written to the current wal 9060** file since it was created on disk (by any connection). This means 9061** that a snapshot cannot be taken on a wal mode database with no wal 9062** file immediately after it is first opened. At least one transaction 9063** must be written to it first. 9064** </ul> 9065** 9066** This function may also return SQLITE_NOMEM. If it is called with the 9067** database handle in autocommit mode but fails for some other reason, 9068** whether or not a read transaction is opened on schema S is undefined. 9069** 9070** The [sqlite3_snapshot] object returned from a successful call to 9071** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 9072** to avoid a memory leak. 9073** 9074** The [sqlite3_snapshot_get()] interface is only available when the 9075** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9076*/ 9077SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 9078 sqlite3 *db, 9079 const char *zSchema, 9080 sqlite3_snapshot **ppSnapshot 9081); 9082 9083/* 9084** CAPI3REF: Start a read transaction on an historical snapshot 9085** METHOD: sqlite3_snapshot 9086** 9087** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read 9088** transaction or upgrades an existing one for schema S of 9089** [database connection] D such that the read transaction refers to 9090** historical [snapshot] P, rather than the most recent change to the 9091** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK 9092** on success or an appropriate [error code] if it fails. 9093** 9094** ^In order to succeed, the database connection must not be in 9095** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there 9096** is already a read transaction open on schema S, then the database handle 9097** must have no active statements (SELECT statements that have been passed 9098** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()). 9099** SQLITE_ERROR is returned if either of these conditions is violated, or 9100** if schema S does not exist, or if the snapshot object is invalid. 9101** 9102** ^A call to sqlite3_snapshot_open() will fail to open if the specified 9103** snapshot has been overwritten by a [checkpoint]. In this case 9104** SQLITE_ERROR_SNAPSHOT is returned. 9105** 9106** If there is already a read transaction open when this function is 9107** invoked, then the same read transaction remains open (on the same 9108** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT 9109** is returned. If another error code - for example SQLITE_PROTOCOL or an 9110** SQLITE_IOERR error code - is returned, then the final state of the 9111** read transaction is undefined. If SQLITE_OK is returned, then the 9112** read transaction is now open on database snapshot P. 9113** 9114** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 9115** database connection D does not know that the database file for 9116** schema S is in [WAL mode]. A database connection might not know 9117** that the database file is in [WAL mode] if there has been no prior 9118** I/O on that database connection, or if the database entered [WAL mode] 9119** after the most recent I/O on the database connection.)^ 9120** (Hint: Run "[PRAGMA application_id]" against a newly opened 9121** database connection in order to make it ready to use snapshots.) 9122** 9123** The [sqlite3_snapshot_open()] interface is only available when the 9124** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9125*/ 9126SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 9127 sqlite3 *db, 9128 const char *zSchema, 9129 sqlite3_snapshot *pSnapshot 9130); 9131 9132/* 9133** CAPI3REF: Destroy a snapshot 9134** DESTRUCTOR: sqlite3_snapshot 9135** 9136** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 9137** The application must eventually free every [sqlite3_snapshot] object 9138** using this routine to avoid a memory leak. 9139** 9140** The [sqlite3_snapshot_free()] interface is only available when the 9141** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9142*/ 9143SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 9144 9145/* 9146** CAPI3REF: Compare the ages of two snapshot handles. 9147** METHOD: sqlite3_snapshot 9148** 9149** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 9150** of two valid snapshot handles. 9151** 9152** If the two snapshot handles are not associated with the same database 9153** file, the result of the comparison is undefined. 9154** 9155** Additionally, the result of the comparison is only valid if both of the 9156** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 9157** last time the wal file was deleted. The wal file is deleted when the 9158** database is changed back to rollback mode or when the number of database 9159** clients drops to zero. If either snapshot handle was obtained before the 9160** wal file was last deleted, the value returned by this function 9161** is undefined. 9162** 9163** Otherwise, this API returns a negative value if P1 refers to an older 9164** snapshot than P2, zero if the two handles refer to the same database 9165** snapshot, and a positive value if P1 is a newer snapshot than P2. 9166** 9167** This interface is only available if SQLite is compiled with the 9168** [SQLITE_ENABLE_SNAPSHOT] option. 9169*/ 9170SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 9171 sqlite3_snapshot *p1, 9172 sqlite3_snapshot *p2 9173); 9174 9175/* 9176** CAPI3REF: Recover snapshots from a wal file 9177** METHOD: sqlite3_snapshot 9178** 9179** If a [WAL file] remains on disk after all database connections close 9180** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control] 9181** or because the last process to have the database opened exited without 9182** calling [sqlite3_close()]) and a new connection is subsequently opened 9183** on that database and [WAL file], the [sqlite3_snapshot_open()] interface 9184** will only be able to open the last transaction added to the WAL file 9185** even though the WAL file contains other valid transactions. 9186** 9187** This function attempts to scan the WAL file associated with database zDb 9188** of database handle db and make all valid snapshots available to 9189** sqlite3_snapshot_open(). It is an error if there is already a read 9190** transaction open on the database, or if the database is not a WAL mode 9191** database. 9192** 9193** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 9194** 9195** This interface is only available if SQLite is compiled with the 9196** [SQLITE_ENABLE_SNAPSHOT] option. 9197*/ 9198SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 9199 9200/* 9201** CAPI3REF: Serialize a database 9202** 9203** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory 9204** that is a serialization of the S database on [database connection] D. 9205** If P is not a NULL pointer, then the size of the database in bytes 9206** is written into *P. 9207** 9208** For an ordinary on-disk database file, the serialization is just a 9209** copy of the disk file. For an in-memory database or a "TEMP" database, 9210** the serialization is the same sequence of bytes which would be written 9211** to disk if that database where backed up to disk. 9212** 9213** The usual case is that sqlite3_serialize() copies the serialization of 9214** the database into memory obtained from [sqlite3_malloc64()] and returns 9215** a pointer to that memory. The caller is responsible for freeing the 9216** returned value to avoid a memory leak. However, if the F argument 9217** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations 9218** are made, and the sqlite3_serialize() function will return a pointer 9219** to the contiguous memory representation of the database that SQLite 9220** is currently using for that database, or NULL if the no such contiguous 9221** memory representation of the database exists. A contiguous memory 9222** representation of the database will usually only exist if there has 9223** been a prior call to [sqlite3_deserialize(D,S,...)] with the same 9224** values of D and S. 9225** The size of the database is written into *P even if the 9226** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy 9227** of the database exists. 9228** 9229** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the 9230** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory 9231** allocation error occurs. 9232** 9233** This interface is only available if SQLite is compiled with the 9234** [SQLITE_ENABLE_DESERIALIZE] option. 9235*/ 9236unsigned char *sqlite3_serialize( 9237 sqlite3 *db, /* The database connection */ 9238 const char *zSchema, /* Which DB to serialize. ex: "main", "temp", ... */ 9239 sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */ 9240 unsigned int mFlags /* Zero or more SQLITE_SERIALIZE_* flags */ 9241); 9242 9243/* 9244** CAPI3REF: Flags for sqlite3_serialize 9245** 9246** Zero or more of the following constants can be OR-ed together for 9247** the F argument to [sqlite3_serialize(D,S,P,F)]. 9248** 9249** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return 9250** a pointer to contiguous in-memory database that it is currently using, 9251** without making a copy of the database. If SQLite is not currently using 9252** a contiguous in-memory database, then this option causes 9253** [sqlite3_serialize()] to return a NULL pointer. SQLite will only be 9254** using a contiguous in-memory database if it has been initialized by a 9255** prior call to [sqlite3_deserialize()]. 9256*/ 9257#define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */ 9258 9259/* 9260** CAPI3REF: Deserialize a database 9261** 9262** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the 9263** [database connection] D to disconnect from database S and then 9264** reopen S as an in-memory database based on the serialization contained 9265** in P. The serialized database P is N bytes in size. M is the size of 9266** the buffer P, which might be larger than N. If M is larger than N, and 9267** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is 9268** permitted to add content to the in-memory database as long as the total 9269** size does not exceed M bytes. 9270** 9271** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will 9272** invoke sqlite3_free() on the serialization buffer when the database 9273** connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then 9274** SQLite will try to increase the buffer size using sqlite3_realloc64() 9275** if writes on the database cause it to grow larger than M bytes. 9276** 9277** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the 9278** database is currently in a read transaction or is involved in a backup 9279** operation. 9280** 9281** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the 9282** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then 9283** [sqlite3_free()] is invoked on argument P prior to returning. 9284** 9285** This interface is only available if SQLite is compiled with the 9286** [SQLITE_ENABLE_DESERIALIZE] option. 9287*/ 9288int sqlite3_deserialize( 9289 sqlite3 *db, /* The database connection */ 9290 const char *zSchema, /* Which DB to reopen with the deserialization */ 9291 unsigned char *pData, /* The serialized database content */ 9292 sqlite3_int64 szDb, /* Number bytes in the deserialization */ 9293 sqlite3_int64 szBuf, /* Total size of buffer pData[] */ 9294 unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */ 9295); 9296 9297/* 9298** CAPI3REF: Flags for sqlite3_deserialize() 9299** 9300** The following are allowed values for 6th argument (the F argument) to 9301** the [sqlite3_deserialize(D,S,P,N,M,F)] interface. 9302** 9303** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization 9304** in the P argument is held in memory obtained from [sqlite3_malloc64()] 9305** and that SQLite should take ownership of this memory and automatically 9306** free it when it has finished using it. Without this flag, the caller 9307** is responsible for freeing any dynamically allocated memory. 9308** 9309** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to 9310** grow the size of the database using calls to [sqlite3_realloc64()]. This 9311** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used. 9312** Without this flag, the deserialized database cannot increase in size beyond 9313** the number of bytes specified by the M parameter. 9314** 9315** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database 9316** should be treated as read-only. 9317*/ 9318#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */ 9319#define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */ 9320#define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */ 9321 9322/* 9323** Undo the hack that converts floating point types to integer for 9324** builds on processors without floating point support. 9325*/ 9326#ifdef SQLITE_OMIT_FLOATING_POINT 9327# undef double 9328#endif 9329 9330#ifdef __cplusplus 9331} /* End of the 'extern "C"' block */ 9332#endif 9333#endif /* SQLITE3_H */ 9334