1/* 2** 2001 September 15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are suppose 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** Add the ability to override 'extern' 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51 52/* 53** These no-op macros are used in front of interfaces to mark those 54** interfaces as either deprecated or experimental. New applications 55** should not use deprecated interfaces - they are supported for backwards 56** compatibility only. Application writers should be aware that 57** experimental interfaces are subject to change in point releases. 58** 59** These macros used to resolve to various kinds of compiler magic that 60** would generate warning messages when they were used. But that 61** compiler magic ended up generating such a flurry of bug reports 62** that we have taken it all out and gone back to using simple 63** noop macros. 64*/ 65#define SQLITE_DEPRECATED 66#define SQLITE_EXPERIMENTAL 67 68/* 69** Ensure these symbols were not defined by some previous header file. 70*/ 71#ifdef SQLITE_VERSION 72# undef SQLITE_VERSION 73#endif 74#ifdef SQLITE_VERSION_NUMBER 75# undef SQLITE_VERSION_NUMBER 76#endif 77 78/* 79** CAPI3REF: Compile-Time Library Version Numbers 80** 81** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 82** evaluates to a string literal that is the SQLite version in the 83** format "X.Y.Z" where X is the major version number (always 3 for 84** SQLite3) and Y is the minor version number and Z is the release number.)^ 85** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 86** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 87** numbers used in [SQLITE_VERSION].)^ 88** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 89** be larger than the release from which it is derived. Either Y will 90** be held constant and Z will be incremented or else Y will be incremented 91** and Z will be reset to zero. 92** 93** Since version 3.6.18, SQLite source code has been stored in the 94** <a href="http://www.fossil-scm.org/">Fossil configuration management 95** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 96** a string which identifies a particular check-in of SQLite 97** within its configuration management system. ^The SQLITE_SOURCE_ID 98** string contains the date and time of the check-in (UTC) and an SHA1 99** hash of the entire source tree. 100** 101** See also: [sqlite3_libversion()], 102** [sqlite3_libversion_number()], [sqlite3_sourceid()], 103** [sqlite_version()] and [sqlite_source_id()]. 104*/ 105#define SQLITE_VERSION "--VERS--" 106#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 107#define SQLITE_SOURCE_ID "--SOURCE-ID--" 108 109/* 110** CAPI3REF: Run-Time Library Version Numbers 111** KEYWORDS: sqlite3_version, sqlite3_sourceid 112** 113** These interfaces provide the same information as the [SQLITE_VERSION], 114** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 115** but are associated with the library instead of the header file. ^(Cautious 116** programmers might include assert() statements in their application to 117** verify that values returned by these interfaces match the macros in 118** the header, and thus insure that the application is 119** compiled with matching library and header files. 120** 121** <blockquote><pre> 122** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 123** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 124** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 125** </pre></blockquote>)^ 126** 127** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 128** macro. ^The sqlite3_libversion() function returns a pointer to the 129** to the sqlite3_version[] string constant. The sqlite3_libversion() 130** function is provided for use in DLLs since DLL users usually do not have 131** direct access to string constants within the DLL. ^The 132** sqlite3_libversion_number() function returns an integer equal to 133** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 134** a pointer to a string constant whose value is the same as the 135** [SQLITE_SOURCE_ID] C preprocessor macro. 136** 137** See also: [sqlite_version()] and [sqlite_source_id()]. 138*/ 139SQLITE_EXTERN const char sqlite3_version[]; 140const char *sqlite3_libversion(void); 141const char *sqlite3_sourceid(void); 142int sqlite3_libversion_number(void); 143 144/* 145** CAPI3REF: Run-Time Library Compilation Options Diagnostics 146** 147** ^The sqlite3_compileoption_used() function returns 0 or 1 148** indicating whether the specified option was defined at 149** compile time. ^The SQLITE_ prefix may be omitted from the 150** option name passed to sqlite3_compileoption_used(). 151** 152** ^The sqlite3_compileoption_get() function allows iterating 153** over the list of options that were defined at compile time by 154** returning the N-th compile time option string. ^If N is out of range, 155** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 156** prefix is omitted from any strings returned by 157** sqlite3_compileoption_get(). 158** 159** ^Support for the diagnostic functions sqlite3_compileoption_used() 160** and sqlite3_compileoption_get() may be omitted by specifying the 161** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 162** 163** See also: SQL functions [sqlite_compileoption_used()] and 164** [sqlite_compileoption_get()] and the [compile_options pragma]. 165*/ 166#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 167int sqlite3_compileoption_used(const char *zOptName); 168const char *sqlite3_compileoption_get(int N); 169#endif 170 171/* 172** CAPI3REF: Test To See If The Library Is Threadsafe 173** 174** ^The sqlite3_threadsafe() function returns zero if and only if 175** SQLite was compiled with mutexing code omitted due to the 176** [SQLITE_THREADSAFE] compile-time option being set to 0. 177** 178** SQLite can be compiled with or without mutexes. When 179** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 180** are enabled and SQLite is threadsafe. When the 181** [SQLITE_THREADSAFE] macro is 0, 182** the mutexes are omitted. Without the mutexes, it is not safe 183** to use SQLite concurrently from more than one thread. 184** 185** Enabling mutexes incurs a measurable performance penalty. 186** So if speed is of utmost importance, it makes sense to disable 187** the mutexes. But for maximum safety, mutexes should be enabled. 188** ^The default behavior is for mutexes to be enabled. 189** 190** This interface can be used by an application to make sure that the 191** version of SQLite that it is linking against was compiled with 192** the desired setting of the [SQLITE_THREADSAFE] macro. 193** 194** This interface only reports on the compile-time mutex setting 195** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 196** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 197** can be fully or partially disabled using a call to [sqlite3_config()] 198** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 199** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the 200** sqlite3_threadsafe() function shows only the compile-time setting of 201** thread safety, not any run-time changes to that setting made by 202** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 203** is unchanged by calls to sqlite3_config().)^ 204** 205** See the [threading mode] documentation for additional information. 206*/ 207int sqlite3_threadsafe(void); 208 209/* 210** CAPI3REF: Database Connection Handle 211** KEYWORDS: {database connection} {database connections} 212** 213** Each open SQLite database is represented by a pointer to an instance of 214** the opaque structure named "sqlite3". It is useful to think of an sqlite3 215** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 216** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 217** and [sqlite3_close_v2()] are its destructors. There are many other 218** interfaces (such as 219** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 220** [sqlite3_busy_timeout()] to name but three) that are methods on an 221** sqlite3 object. 222*/ 223typedef struct sqlite3 sqlite3; 224 225/* 226** CAPI3REF: 64-Bit Integer Types 227** KEYWORDS: sqlite_int64 sqlite_uint64 228** 229** Because there is no cross-platform way to specify 64-bit integer types 230** SQLite includes typedefs for 64-bit signed and unsigned integers. 231** 232** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 233** The sqlite_int64 and sqlite_uint64 types are supported for backwards 234** compatibility only. 235** 236** ^The sqlite3_int64 and sqlite_int64 types can store integer values 237** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 238** sqlite3_uint64 and sqlite_uint64 types can store integer values 239** between 0 and +18446744073709551615 inclusive. 240*/ 241#ifdef SQLITE_INT64_TYPE 242 typedef SQLITE_INT64_TYPE sqlite_int64; 243 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 244#elif defined(_MSC_VER) || defined(__BORLANDC__) 245 typedef __int64 sqlite_int64; 246 typedef unsigned __int64 sqlite_uint64; 247#else 248 typedef long long int sqlite_int64; 249 typedef unsigned long long int sqlite_uint64; 250#endif 251typedef sqlite_int64 sqlite3_int64; 252typedef sqlite_uint64 sqlite3_uint64; 253 254/* 255** If compiling for a processor that lacks floating point support, 256** substitute integer for floating-point. 257*/ 258#ifdef SQLITE_OMIT_FLOATING_POINT 259# define double sqlite3_int64 260#endif 261 262/* 263** CAPI3REF: Closing A Database Connection 264** 265** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 266** for the [sqlite3] object. 267** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 268** the [sqlite3] object is successfully destroyed and all associated 269** resources are deallocated. 270** 271** ^If the database connection is associated with unfinalized prepared 272** statements or unfinished sqlite3_backup objects then sqlite3_close() 273** will leave the database connection open and return [SQLITE_BUSY]. 274** ^If sqlite3_close_v2() is called with unfinalized prepared statements 275** and/or unfinished sqlite3_backups, then the database connection becomes 276** an unusable "zombie" which will automatically be deallocated when the 277** last prepared statement is finalized or the last sqlite3_backup is 278** finished. The sqlite3_close_v2() interface is intended for use with 279** host languages that are garbage collected, and where the order in which 280** destructors are called is arbitrary. 281** 282** Applications should [sqlite3_finalize | finalize] all [prepared statements], 283** [sqlite3_blob_close | close] all [BLOB handles], and 284** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 285** with the [sqlite3] object prior to attempting to close the object. ^If 286** sqlite3_close_v2() is called on a [database connection] that still has 287** outstanding [prepared statements], [BLOB handles], and/or 288** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation 289** of resources is deferred until all [prepared statements], [BLOB handles], 290** and [sqlite3_backup] objects are also destroyed. 291** 292** ^If an [sqlite3] object is destroyed while a transaction is open, 293** the transaction is automatically rolled back. 294** 295** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 296** must be either a NULL 297** pointer or an [sqlite3] object pointer obtained 298** from [sqlite3_open()], [sqlite3_open16()], or 299** [sqlite3_open_v2()], and not previously closed. 300** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 301** argument is a harmless no-op. 302*/ 303int sqlite3_close(sqlite3*); 304int sqlite3_close_v2(sqlite3*); 305 306/* 307** The type for a callback function. 308** This is legacy and deprecated. It is included for historical 309** compatibility and is not documented. 310*/ 311typedef int (*sqlite3_callback)(void*,int,char**, char**); 312 313/* 314** CAPI3REF: One-Step Query Execution Interface 315** 316** The sqlite3_exec() interface is a convenience wrapper around 317** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 318** that allows an application to run multiple statements of SQL 319** without having to use a lot of C code. 320** 321** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 322** semicolon-separate SQL statements passed into its 2nd argument, 323** in the context of the [database connection] passed in as its 1st 324** argument. ^If the callback function of the 3rd argument to 325** sqlite3_exec() is not NULL, then it is invoked for each result row 326** coming out of the evaluated SQL statements. ^The 4th argument to 327** sqlite3_exec() is relayed through to the 1st argument of each 328** callback invocation. ^If the callback pointer to sqlite3_exec() 329** is NULL, then no callback is ever invoked and result rows are 330** ignored. 331** 332** ^If an error occurs while evaluating the SQL statements passed into 333** sqlite3_exec(), then execution of the current statement stops and 334** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 335** is not NULL then any error message is written into memory obtained 336** from [sqlite3_malloc()] and passed back through the 5th parameter. 337** To avoid memory leaks, the application should invoke [sqlite3_free()] 338** on error message strings returned through the 5th parameter of 339** of sqlite3_exec() after the error message string is no longer needed. 340** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 341** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 342** NULL before returning. 343** 344** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 345** routine returns SQLITE_ABORT without invoking the callback again and 346** without running any subsequent SQL statements. 347** 348** ^The 2nd argument to the sqlite3_exec() callback function is the 349** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 350** callback is an array of pointers to strings obtained as if from 351** [sqlite3_column_text()], one for each column. ^If an element of a 352** result row is NULL then the corresponding string pointer for the 353** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 354** sqlite3_exec() callback is an array of pointers to strings where each 355** entry represents the name of corresponding result column as obtained 356** from [sqlite3_column_name()]. 357** 358** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 359** to an empty string, or a pointer that contains only whitespace and/or 360** SQL comments, then no SQL statements are evaluated and the database 361** is not changed. 362** 363** Restrictions: 364** 365** <ul> 366** <li> The application must insure that the 1st parameter to sqlite3_exec() 367** is a valid and open [database connection]. 368** <li> The application must not close the [database connection] specified by 369** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 370** <li> The application must not modify the SQL statement text passed into 371** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 372** </ul> 373*/ 374int sqlite3_exec( 375 sqlite3*, /* An open database */ 376 const char *sql, /* SQL to be evaluated */ 377 int (*callback)(void*,int,char**,char**), /* Callback function */ 378 void *, /* 1st argument to callback */ 379 char **errmsg /* Error msg written here */ 380); 381 382/* 383** CAPI3REF: Result Codes 384** KEYWORDS: {result code definitions} 385** 386** Many SQLite functions return an integer result code from the set shown 387** here in order to indicate success or failure. 388** 389** New error codes may be added in future versions of SQLite. 390** 391** See also: [extended result code definitions] 392*/ 393#define SQLITE_OK 0 /* Successful result */ 394/* beginning-of-error-codes */ 395#define SQLITE_ERROR 1 /* SQL error or missing database */ 396#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 397#define SQLITE_PERM 3 /* Access permission denied */ 398#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 399#define SQLITE_BUSY 5 /* The database file is locked */ 400#define SQLITE_LOCKED 6 /* A table in the database is locked */ 401#define SQLITE_NOMEM 7 /* A malloc() failed */ 402#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 403#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 404#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 405#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 406#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 407#define SQLITE_FULL 13 /* Insertion failed because database is full */ 408#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 409#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 410#define SQLITE_EMPTY 16 /* Database is empty */ 411#define SQLITE_SCHEMA 17 /* The database schema changed */ 412#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 413#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 414#define SQLITE_MISMATCH 20 /* Data type mismatch */ 415#define SQLITE_MISUSE 21 /* Library used incorrectly */ 416#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 417#define SQLITE_AUTH 23 /* Authorization denied */ 418#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 419#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 420#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 421#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 422#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 423#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 424#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 425/* end-of-error-codes */ 426 427/* 428** CAPI3REF: Extended Result Codes 429** KEYWORDS: {extended result code definitions} 430** 431** In its default configuration, SQLite API routines return one of 30 integer 432** [result codes]. However, experience has shown that many of 433** these result codes are too coarse-grained. They do not provide as 434** much information about problems as programmers might like. In an effort to 435** address this, newer versions of SQLite (version 3.3.8 and later) include 436** support for additional result codes that provide more detailed information 437** about errors. These [extended result codes] are enabled or disabled 438** on a per database connection basis using the 439** [sqlite3_extended_result_codes()] API. Or, the extended code for 440** the most recent error can be obtained using 441** [sqlite3_extended_errcode()]. 442*/ 443#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 444#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 445#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 446#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 447#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 448#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 449#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 450#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 451#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 452#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 453#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 454#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 455#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 456#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 457#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 458#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 459#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 460#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 461#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 462#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 463#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 464#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 465#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 466#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 467#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 468#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 469#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 470#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 471#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 472#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 473#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 474#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 475#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 476#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 477#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 478#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 479#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 480#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 481#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 482#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 483#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 484#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 485#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 486#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 487#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 488#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 489#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 490#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 491#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 492#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 493#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 494#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 495#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 496 497/* 498** CAPI3REF: Flags For File Open Operations 499** 500** These bit values are intended for use in the 501** 3rd parameter to the [sqlite3_open_v2()] interface and 502** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 503*/ 504#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 505#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 506#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 507#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 508#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 509#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 510#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 511#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 512#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 513#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 514#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 515#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 516#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 517#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 518#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 519#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 520#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 521#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 522#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 523#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 524 525/* Reserved: 0x00F00000 */ 526 527/* 528** CAPI3REF: Device Characteristics 529** 530** The xDeviceCharacteristics method of the [sqlite3_io_methods] 531** object returns an integer which is a vector of these 532** bit values expressing I/O characteristics of the mass storage 533** device that holds the file that the [sqlite3_io_methods] 534** refers to. 535** 536** The SQLITE_IOCAP_ATOMIC property means that all writes of 537** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 538** mean that writes of blocks that are nnn bytes in size and 539** are aligned to an address which is an integer multiple of 540** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 541** that when data is appended to a file, the data is appended 542** first then the size of the file is extended, never the other 543** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 544** information is written to disk in the same order as calls 545** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 546** after reboot following a crash or power loss, the only bytes in a 547** file that were written at the application level might have changed 548** and that adjacent bytes, even bytes within the same sector are 549** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 550** flag indicate that a file cannot be deleted when open. The 551** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 552** read-only media and cannot be changed even by processes with 553** elevated privileges. 554*/ 555#define SQLITE_IOCAP_ATOMIC 0x00000001 556#define SQLITE_IOCAP_ATOMIC512 0x00000002 557#define SQLITE_IOCAP_ATOMIC1K 0x00000004 558#define SQLITE_IOCAP_ATOMIC2K 0x00000008 559#define SQLITE_IOCAP_ATOMIC4K 0x00000010 560#define SQLITE_IOCAP_ATOMIC8K 0x00000020 561#define SQLITE_IOCAP_ATOMIC16K 0x00000040 562#define SQLITE_IOCAP_ATOMIC32K 0x00000080 563#define SQLITE_IOCAP_ATOMIC64K 0x00000100 564#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 565#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 566#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 567#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 568#define SQLITE_IOCAP_IMMUTABLE 0x00002000 569 570/* 571** CAPI3REF: File Locking Levels 572** 573** SQLite uses one of these integer values as the second 574** argument to calls it makes to the xLock() and xUnlock() methods 575** of an [sqlite3_io_methods] object. 576*/ 577#define SQLITE_LOCK_NONE 0 578#define SQLITE_LOCK_SHARED 1 579#define SQLITE_LOCK_RESERVED 2 580#define SQLITE_LOCK_PENDING 3 581#define SQLITE_LOCK_EXCLUSIVE 4 582 583/* 584** CAPI3REF: Synchronization Type Flags 585** 586** When SQLite invokes the xSync() method of an 587** [sqlite3_io_methods] object it uses a combination of 588** these integer values as the second argument. 589** 590** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 591** sync operation only needs to flush data to mass storage. Inode 592** information need not be flushed. If the lower four bits of the flag 593** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 594** If the lower four bits equal SQLITE_SYNC_FULL, that means 595** to use Mac OS X style fullsync instead of fsync(). 596** 597** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 598** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 599** settings. The [synchronous pragma] determines when calls to the 600** xSync VFS method occur and applies uniformly across all platforms. 601** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 602** energetic or rigorous or forceful the sync operations are and 603** only make a difference on Mac OSX for the default SQLite code. 604** (Third-party VFS implementations might also make the distinction 605** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 606** operating systems natively supported by SQLite, only Mac OSX 607** cares about the difference.) 608*/ 609#define SQLITE_SYNC_NORMAL 0x00002 610#define SQLITE_SYNC_FULL 0x00003 611#define SQLITE_SYNC_DATAONLY 0x00010 612 613/* 614** CAPI3REF: OS Interface Open File Handle 615** 616** An [sqlite3_file] object represents an open file in the 617** [sqlite3_vfs | OS interface layer]. Individual OS interface 618** implementations will 619** want to subclass this object by appending additional fields 620** for their own use. The pMethods entry is a pointer to an 621** [sqlite3_io_methods] object that defines methods for performing 622** I/O operations on the open file. 623*/ 624typedef struct sqlite3_file sqlite3_file; 625struct sqlite3_file { 626 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 627}; 628 629/* 630** CAPI3REF: OS Interface File Virtual Methods Object 631** 632** Every file opened by the [sqlite3_vfs.xOpen] method populates an 633** [sqlite3_file] object (or, more commonly, a subclass of the 634** [sqlite3_file] object) with a pointer to an instance of this object. 635** This object defines the methods used to perform various operations 636** against the open file represented by the [sqlite3_file] object. 637** 638** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 639** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 640** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 641** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 642** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 643** to NULL. 644** 645** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 646** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 647** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 648** flag may be ORed in to indicate that only the data of the file 649** and not its inode needs to be synced. 650** 651** The integer values to xLock() and xUnlock() are one of 652** <ul> 653** <li> [SQLITE_LOCK_NONE], 654** <li> [SQLITE_LOCK_SHARED], 655** <li> [SQLITE_LOCK_RESERVED], 656** <li> [SQLITE_LOCK_PENDING], or 657** <li> [SQLITE_LOCK_EXCLUSIVE]. 658** </ul> 659** xLock() increases the lock. xUnlock() decreases the lock. 660** The xCheckReservedLock() method checks whether any database connection, 661** either in this process or in some other process, is holding a RESERVED, 662** PENDING, or EXCLUSIVE lock on the file. It returns true 663** if such a lock exists and false otherwise. 664** 665** The xFileControl() method is a generic interface that allows custom 666** VFS implementations to directly control an open file using the 667** [sqlite3_file_control()] interface. The second "op" argument is an 668** integer opcode. The third argument is a generic pointer intended to 669** point to a structure that may contain arguments or space in which to 670** write return values. Potential uses for xFileControl() might be 671** functions to enable blocking locks with timeouts, to change the 672** locking strategy (for example to use dot-file locks), to inquire 673** about the status of a lock, or to break stale locks. The SQLite 674** core reserves all opcodes less than 100 for its own use. 675** A [file control opcodes | list of opcodes] less than 100 is available. 676** Applications that define a custom xFileControl method should use opcodes 677** greater than 100 to avoid conflicts. VFS implementations should 678** return [SQLITE_NOTFOUND] for file control opcodes that they do not 679** recognize. 680** 681** The xSectorSize() method returns the sector size of the 682** device that underlies the file. The sector size is the 683** minimum write that can be performed without disturbing 684** other bytes in the file. The xDeviceCharacteristics() 685** method returns a bit vector describing behaviors of the 686** underlying device: 687** 688** <ul> 689** <li> [SQLITE_IOCAP_ATOMIC] 690** <li> [SQLITE_IOCAP_ATOMIC512] 691** <li> [SQLITE_IOCAP_ATOMIC1K] 692** <li> [SQLITE_IOCAP_ATOMIC2K] 693** <li> [SQLITE_IOCAP_ATOMIC4K] 694** <li> [SQLITE_IOCAP_ATOMIC8K] 695** <li> [SQLITE_IOCAP_ATOMIC16K] 696** <li> [SQLITE_IOCAP_ATOMIC32K] 697** <li> [SQLITE_IOCAP_ATOMIC64K] 698** <li> [SQLITE_IOCAP_SAFE_APPEND] 699** <li> [SQLITE_IOCAP_SEQUENTIAL] 700** </ul> 701** 702** The SQLITE_IOCAP_ATOMIC property means that all writes of 703** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 704** mean that writes of blocks that are nnn bytes in size and 705** are aligned to an address which is an integer multiple of 706** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 707** that when data is appended to a file, the data is appended 708** first then the size of the file is extended, never the other 709** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 710** information is written to disk in the same order as calls 711** to xWrite(). 712** 713** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 714** in the unread portions of the buffer with zeros. A VFS that 715** fails to zero-fill short reads might seem to work. However, 716** failure to zero-fill short reads will eventually lead to 717** database corruption. 718*/ 719typedef struct sqlite3_io_methods sqlite3_io_methods; 720struct sqlite3_io_methods { 721 int iVersion; 722 int (*xClose)(sqlite3_file*); 723 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 724 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 725 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 726 int (*xSync)(sqlite3_file*, int flags); 727 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 728 int (*xLock)(sqlite3_file*, int); 729 int (*xUnlock)(sqlite3_file*, int); 730 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 731 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 732 int (*xSectorSize)(sqlite3_file*); 733 int (*xDeviceCharacteristics)(sqlite3_file*); 734 /* Methods above are valid for version 1 */ 735 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 736 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 737 void (*xShmBarrier)(sqlite3_file*); 738 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 739 /* Methods above are valid for version 2 */ 740 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 741 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 742 /* Methods above are valid for version 3 */ 743 /* Additional methods may be added in future releases */ 744}; 745 746/* 747** CAPI3REF: Standard File Control Opcodes 748** KEYWORDS: {file control opcodes} {file control opcode} 749** 750** These integer constants are opcodes for the xFileControl method 751** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 752** interface. 753** 754** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 755** opcode causes the xFileControl method to write the current state of 756** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 757** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 758** into an integer that the pArg argument points to. This capability 759** is used during testing and only needs to be supported when SQLITE_TEST 760** is defined. 761** <ul> 762** <li>[[SQLITE_FCNTL_SIZE_HINT]] 763** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 764** layer a hint of how large the database file will grow to be during the 765** current transaction. This hint is not guaranteed to be accurate but it 766** is often close. The underlying VFS might choose to preallocate database 767** file space based on this hint in order to help writes to the database 768** file run faster. 769** 770** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 771** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 772** extends and truncates the database file in chunks of a size specified 773** by the user. The fourth argument to [sqlite3_file_control()] should 774** point to an integer (type int) containing the new chunk-size to use 775** for the nominated database. Allocating database file space in large 776** chunks (say 1MB at a time), may reduce file-system fragmentation and 777** improve performance on some systems. 778** 779** <li>[[SQLITE_FCNTL_FILE_POINTER]] 780** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 781** to the [sqlite3_file] object associated with a particular database 782** connection. See the [sqlite3_file_control()] documentation for 783** additional information. 784** 785** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 786** No longer in use. 787** 788** <li>[[SQLITE_FCNTL_SYNC]] 789** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 790** sent to the VFS immediately before the xSync method is invoked on a 791** database file descriptor. Or, if the xSync method is not invoked 792** because the user has configured SQLite with 793** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 794** of the xSync method. In most cases, the pointer argument passed with 795** this file-control is NULL. However, if the database file is being synced 796** as part of a multi-database commit, the argument points to a nul-terminated 797** string containing the transactions master-journal file name. VFSes that 798** do not need this signal should silently ignore this opcode. Applications 799** should not call [sqlite3_file_control()] with this opcode as doing so may 800** disrupt the operation of the specialized VFSes that do require it. 801** 802** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 803** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 804** and sent to the VFS after a transaction has been committed immediately 805** but before the database is unlocked. VFSes that do not need this signal 806** should silently ignore this opcode. Applications should not call 807** [sqlite3_file_control()] with this opcode as doing so may disrupt the 808** operation of the specialized VFSes that do require it. 809** 810** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 811** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 812** retry counts and intervals for certain disk I/O operations for the 813** windows [VFS] in order to provide robustness in the presence of 814** anti-virus programs. By default, the windows VFS will retry file read, 815** file write, and file delete operations up to 10 times, with a delay 816** of 25 milliseconds before the first retry and with the delay increasing 817** by an additional 25 milliseconds with each subsequent retry. This 818** opcode allows these two values (10 retries and 25 milliseconds of delay) 819** to be adjusted. The values are changed for all database connections 820** within the same process. The argument is a pointer to an array of two 821** integers where the first integer i the new retry count and the second 822** integer is the delay. If either integer is negative, then the setting 823** is not changed but instead the prior value of that setting is written 824** into the array entry, allowing the current retry settings to be 825** interrogated. The zDbName parameter is ignored. 826** 827** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 828** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 829** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 830** write ahead log and shared memory files used for transaction control 831** are automatically deleted when the latest connection to the database 832** closes. Setting persistent WAL mode causes those files to persist after 833** close. Persisting the files is useful when other processes that do not 834** have write permission on the directory containing the database file want 835** to read the database file, as the WAL and shared memory files must exist 836** in order for the database to be readable. The fourth parameter to 837** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 838** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 839** WAL mode. If the integer is -1, then it is overwritten with the current 840** WAL persistence setting. 841** 842** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 843** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 844** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 845** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 846** xDeviceCharacteristics methods. The fourth parameter to 847** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 848** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 849** mode. If the integer is -1, then it is overwritten with the current 850** zero-damage mode setting. 851** 852** <li>[[SQLITE_FCNTL_OVERWRITE]] 853** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 854** a write transaction to indicate that, unless it is rolled back for some 855** reason, the entire database file will be overwritten by the current 856** transaction. This is used by VACUUM operations. 857** 858** <li>[[SQLITE_FCNTL_VFSNAME]] 859** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 860** all [VFSes] in the VFS stack. The names are of all VFS shims and the 861** final bottom-level VFS are written into memory obtained from 862** [sqlite3_malloc()] and the result is stored in the char* variable 863** that the fourth parameter of [sqlite3_file_control()] points to. 864** The caller is responsible for freeing the memory when done. As with 865** all file-control actions, there is no guarantee that this will actually 866** do anything. Callers should initialize the char* variable to a NULL 867** pointer in case this file-control is not implemented. This file-control 868** is intended for diagnostic use only. 869** 870** <li>[[SQLITE_FCNTL_PRAGMA]] 871** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 872** file control is sent to the open [sqlite3_file] object corresponding 873** to the database file to which the pragma statement refers. ^The argument 874** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 875** pointers to strings (char**) in which the second element of the array 876** is the name of the pragma and the third element is the argument to the 877** pragma or NULL if the pragma has no argument. ^The handler for an 878** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 879** of the char** argument point to a string obtained from [sqlite3_mprintf()] 880** or the equivalent and that string will become the result of the pragma or 881** the error message if the pragma fails. ^If the 882** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 883** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 884** file control returns [SQLITE_OK], then the parser assumes that the 885** VFS has handled the PRAGMA itself and the parser generates a no-op 886** prepared statement. ^If the [SQLITE_FCNTL_PRAGMA] file control returns 887** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 888** that the VFS encountered an error while handling the [PRAGMA] and the 889** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 890** file control occurs at the beginning of pragma statement analysis and so 891** it is able to override built-in [PRAGMA] statements. 892** 893** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 894** ^The [SQLITE_FCNTL_BUSYHANDLER] 895** file-control may be invoked by SQLite on the database file handle 896** shortly after it is opened in order to provide a custom VFS with access 897** to the connections busy-handler callback. The argument is of type (void **) 898** - an array of two (void *) values. The first (void *) actually points 899** to a function of type (int (*)(void *)). In order to invoke the connections 900** busy-handler, this function should be invoked with the second (void *) in 901** the array as the only argument. If it returns non-zero, then the operation 902** should be retried. If it returns zero, the custom VFS should abandon the 903** current operation. 904** 905** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 906** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 907** to have SQLite generate a 908** temporary filename using the same algorithm that is followed to generate 909** temporary filenames for TEMP tables and other internal uses. The 910** argument should be a char** which will be filled with the filename 911** written into memory obtained from [sqlite3_malloc()]. The caller should 912** invoke [sqlite3_free()] on the result to avoid a memory leak. 913** 914** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 915** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 916** maximum number of bytes that will be used for memory-mapped I/O. 917** The argument is a pointer to a value of type sqlite3_int64 that 918** is an advisory maximum number of bytes in the file to memory map. The 919** pointer is overwritten with the old value. The limit is not changed if 920** the value originally pointed to is negative, and so the current limit 921** can be queried by passing in a pointer to a negative number. This 922** file-control is used internally to implement [PRAGMA mmap_size]. 923** 924** <li>[[SQLITE_FCNTL_TRACE]] 925** The [SQLITE_FCNTL_TRACE] file control provides advisory information 926** to the VFS about what the higher layers of the SQLite stack are doing. 927** This file control is used by some VFS activity tracing [shims]. 928** The argument is a zero-terminated string. Higher layers in the 929** SQLite stack may generate instances of this file control if 930** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 931** 932** <li>[[SQLITE_FCNTL_HAS_MOVED]] 933** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 934** pointer to an integer and it writes a boolean into that integer depending 935** on whether or not the file has been renamed, moved, or deleted since it 936** was first opened. 937** 938** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 939** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 940** opcode causes the xFileControl method to swap the file handle with the one 941** pointed to by the pArg argument. This capability is used during testing 942** and only needs to be supported when SQLITE_TEST is defined. 943** 944** </ul> 945*/ 946#define SQLITE_FCNTL_LOCKSTATE 1 947#define SQLITE_GET_LOCKPROXYFILE 2 948#define SQLITE_SET_LOCKPROXYFILE 3 949#define SQLITE_LAST_ERRNO 4 950#define SQLITE_FCNTL_SIZE_HINT 5 951#define SQLITE_FCNTL_CHUNK_SIZE 6 952#define SQLITE_FCNTL_FILE_POINTER 7 953#define SQLITE_FCNTL_SYNC_OMITTED 8 954#define SQLITE_FCNTL_WIN32_AV_RETRY 9 955#define SQLITE_FCNTL_PERSIST_WAL 10 956#define SQLITE_FCNTL_OVERWRITE 11 957#define SQLITE_FCNTL_VFSNAME 12 958#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 959#define SQLITE_FCNTL_PRAGMA 14 960#define SQLITE_FCNTL_BUSYHANDLER 15 961#define SQLITE_FCNTL_TEMPFILENAME 16 962#define SQLITE_FCNTL_MMAP_SIZE 18 963#define SQLITE_FCNTL_TRACE 19 964#define SQLITE_FCNTL_HAS_MOVED 20 965#define SQLITE_FCNTL_SYNC 21 966#define SQLITE_FCNTL_COMMIT_PHASETWO 22 967#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 968 969/* 970** CAPI3REF: Mutex Handle 971** 972** The mutex module within SQLite defines [sqlite3_mutex] to be an 973** abstract type for a mutex object. The SQLite core never looks 974** at the internal representation of an [sqlite3_mutex]. It only 975** deals with pointers to the [sqlite3_mutex] object. 976** 977** Mutexes are created using [sqlite3_mutex_alloc()]. 978*/ 979typedef struct sqlite3_mutex sqlite3_mutex; 980 981/* 982** CAPI3REF: OS Interface Object 983** 984** An instance of the sqlite3_vfs object defines the interface between 985** the SQLite core and the underlying operating system. The "vfs" 986** in the name of the object stands for "virtual file system". See 987** the [VFS | VFS documentation] for further information. 988** 989** The value of the iVersion field is initially 1 but may be larger in 990** future versions of SQLite. Additional fields may be appended to this 991** object when the iVersion value is increased. Note that the structure 992** of the sqlite3_vfs object changes in the transaction between 993** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 994** modified. 995** 996** The szOsFile field is the size of the subclassed [sqlite3_file] 997** structure used by this VFS. mxPathname is the maximum length of 998** a pathname in this VFS. 999** 1000** Registered sqlite3_vfs objects are kept on a linked list formed by 1001** the pNext pointer. The [sqlite3_vfs_register()] 1002** and [sqlite3_vfs_unregister()] interfaces manage this list 1003** in a thread-safe way. The [sqlite3_vfs_find()] interface 1004** searches the list. Neither the application code nor the VFS 1005** implementation should use the pNext pointer. 1006** 1007** The pNext field is the only field in the sqlite3_vfs 1008** structure that SQLite will ever modify. SQLite will only access 1009** or modify this field while holding a particular static mutex. 1010** The application should never modify anything within the sqlite3_vfs 1011** object once the object has been registered. 1012** 1013** The zName field holds the name of the VFS module. The name must 1014** be unique across all VFS modules. 1015** 1016** [[sqlite3_vfs.xOpen]] 1017** ^SQLite guarantees that the zFilename parameter to xOpen 1018** is either a NULL pointer or string obtained 1019** from xFullPathname() with an optional suffix added. 1020** ^If a suffix is added to the zFilename parameter, it will 1021** consist of a single "-" character followed by no more than 1022** 11 alphanumeric and/or "-" characters. 1023** ^SQLite further guarantees that 1024** the string will be valid and unchanged until xClose() is 1025** called. Because of the previous sentence, 1026** the [sqlite3_file] can safely store a pointer to the 1027** filename if it needs to remember the filename for some reason. 1028** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1029** must invent its own temporary name for the file. ^Whenever the 1030** xFilename parameter is NULL it will also be the case that the 1031** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1032** 1033** The flags argument to xOpen() includes all bits set in 1034** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1035** or [sqlite3_open16()] is used, then flags includes at least 1036** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1037** If xOpen() opens a file read-only then it sets *pOutFlags to 1038** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1039** 1040** ^(SQLite will also add one of the following flags to the xOpen() 1041** call, depending on the object being opened: 1042** 1043** <ul> 1044** <li> [SQLITE_OPEN_MAIN_DB] 1045** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1046** <li> [SQLITE_OPEN_TEMP_DB] 1047** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1048** <li> [SQLITE_OPEN_TRANSIENT_DB] 1049** <li> [SQLITE_OPEN_SUBJOURNAL] 1050** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1051** <li> [SQLITE_OPEN_WAL] 1052** </ul>)^ 1053** 1054** The file I/O implementation can use the object type flags to 1055** change the way it deals with files. For example, an application 1056** that does not care about crash recovery or rollback might make 1057** the open of a journal file a no-op. Writes to this journal would 1058** also be no-ops, and any attempt to read the journal would return 1059** SQLITE_IOERR. Or the implementation might recognize that a database 1060** file will be doing page-aligned sector reads and writes in a random 1061** order and set up its I/O subsystem accordingly. 1062** 1063** SQLite might also add one of the following flags to the xOpen method: 1064** 1065** <ul> 1066** <li> [SQLITE_OPEN_DELETEONCLOSE] 1067** <li> [SQLITE_OPEN_EXCLUSIVE] 1068** </ul> 1069** 1070** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1071** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1072** will be set for TEMP databases and their journals, transient 1073** databases, and subjournals. 1074** 1075** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1076** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1077** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1078** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1079** SQLITE_OPEN_CREATE, is used to indicate that file should always 1080** be created, and that it is an error if it already exists. 1081** It is <i>not</i> used to indicate the file should be opened 1082** for exclusive access. 1083** 1084** ^At least szOsFile bytes of memory are allocated by SQLite 1085** to hold the [sqlite3_file] structure passed as the third 1086** argument to xOpen. The xOpen method does not have to 1087** allocate the structure; it should just fill it in. Note that 1088** the xOpen method must set the sqlite3_file.pMethods to either 1089** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1090** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1091** element will be valid after xOpen returns regardless of the success 1092** or failure of the xOpen call. 1093** 1094** [[sqlite3_vfs.xAccess]] 1095** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1096** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1097** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1098** to test whether a file is at least readable. The file can be a 1099** directory. 1100** 1101** ^SQLite will always allocate at least mxPathname+1 bytes for the 1102** output buffer xFullPathname. The exact size of the output buffer 1103** is also passed as a parameter to both methods. If the output buffer 1104** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1105** handled as a fatal error by SQLite, vfs implementations should endeavor 1106** to prevent this by setting mxPathname to a sufficiently large value. 1107** 1108** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1109** interfaces are not strictly a part of the filesystem, but they are 1110** included in the VFS structure for completeness. 1111** The xRandomness() function attempts to return nBytes bytes 1112** of good-quality randomness into zOut. The return value is 1113** the actual number of bytes of randomness obtained. 1114** The xSleep() method causes the calling thread to sleep for at 1115** least the number of microseconds given. ^The xCurrentTime() 1116** method returns a Julian Day Number for the current date and time as 1117** a floating point value. 1118** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1119** Day Number multiplied by 86400000 (the number of milliseconds in 1120** a 24-hour day). 1121** ^SQLite will use the xCurrentTimeInt64() method to get the current 1122** date and time if that method is available (if iVersion is 2 or 1123** greater and the function pointer is not NULL) and will fall back 1124** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1125** 1126** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1127** are not used by the SQLite core. These optional interfaces are provided 1128** by some VFSes to facilitate testing of the VFS code. By overriding 1129** system calls with functions under its control, a test program can 1130** simulate faults and error conditions that would otherwise be difficult 1131** or impossible to induce. The set of system calls that can be overridden 1132** varies from one VFS to another, and from one version of the same VFS to the 1133** next. Applications that use these interfaces must be prepared for any 1134** or all of these interfaces to be NULL or for their behavior to change 1135** from one release to the next. Applications must not attempt to access 1136** any of these methods if the iVersion of the VFS is less than 3. 1137*/ 1138typedef struct sqlite3_vfs sqlite3_vfs; 1139typedef void (*sqlite3_syscall_ptr)(void); 1140struct sqlite3_vfs { 1141 int iVersion; /* Structure version number (currently 3) */ 1142 int szOsFile; /* Size of subclassed sqlite3_file */ 1143 int mxPathname; /* Maximum file pathname length */ 1144 sqlite3_vfs *pNext; /* Next registered VFS */ 1145 const char *zName; /* Name of this virtual file system */ 1146 void *pAppData; /* Pointer to application-specific data */ 1147 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1148 int flags, int *pOutFlags); 1149 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1150 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1151 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1152 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1153 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1154 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1155 void (*xDlClose)(sqlite3_vfs*, void*); 1156 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1157 int (*xSleep)(sqlite3_vfs*, int microseconds); 1158 int (*xCurrentTime)(sqlite3_vfs*, double*); 1159 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1160 /* 1161 ** The methods above are in version 1 of the sqlite_vfs object 1162 ** definition. Those that follow are added in version 2 or later 1163 */ 1164 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1165 /* 1166 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1167 ** Those below are for version 3 and greater. 1168 */ 1169 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1170 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1171 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1172 /* 1173 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1174 ** New fields may be appended in figure versions. The iVersion 1175 ** value will increment whenever this happens. 1176 */ 1177}; 1178 1179/* 1180** CAPI3REF: Flags for the xAccess VFS method 1181** 1182** These integer constants can be used as the third parameter to 1183** the xAccess method of an [sqlite3_vfs] object. They determine 1184** what kind of permissions the xAccess method is looking for. 1185** With SQLITE_ACCESS_EXISTS, the xAccess method 1186** simply checks whether the file exists. 1187** With SQLITE_ACCESS_READWRITE, the xAccess method 1188** checks whether the named directory is both readable and writable 1189** (in other words, if files can be added, removed, and renamed within 1190** the directory). 1191** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1192** [temp_store_directory pragma], though this could change in a future 1193** release of SQLite. 1194** With SQLITE_ACCESS_READ, the xAccess method 1195** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1196** currently unused, though it might be used in a future release of 1197** SQLite. 1198*/ 1199#define SQLITE_ACCESS_EXISTS 0 1200#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1201#define SQLITE_ACCESS_READ 2 /* Unused */ 1202 1203/* 1204** CAPI3REF: Flags for the xShmLock VFS method 1205** 1206** These integer constants define the various locking operations 1207** allowed by the xShmLock method of [sqlite3_io_methods]. The 1208** following are the only legal combinations of flags to the 1209** xShmLock method: 1210** 1211** <ul> 1212** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1213** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1214** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1215** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1216** </ul> 1217** 1218** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1219** was given on the corresponding lock. 1220** 1221** The xShmLock method can transition between unlocked and SHARED or 1222** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1223** and EXCLUSIVE. 1224*/ 1225#define SQLITE_SHM_UNLOCK 1 1226#define SQLITE_SHM_LOCK 2 1227#define SQLITE_SHM_SHARED 4 1228#define SQLITE_SHM_EXCLUSIVE 8 1229 1230/* 1231** CAPI3REF: Maximum xShmLock index 1232** 1233** The xShmLock method on [sqlite3_io_methods] may use values 1234** between 0 and this upper bound as its "offset" argument. 1235** The SQLite core will never attempt to acquire or release a 1236** lock outside of this range 1237*/ 1238#define SQLITE_SHM_NLOCK 8 1239 1240 1241/* 1242** CAPI3REF: Initialize The SQLite Library 1243** 1244** ^The sqlite3_initialize() routine initializes the 1245** SQLite library. ^The sqlite3_shutdown() routine 1246** deallocates any resources that were allocated by sqlite3_initialize(). 1247** These routines are designed to aid in process initialization and 1248** shutdown on embedded systems. Workstation applications using 1249** SQLite normally do not need to invoke either of these routines. 1250** 1251** A call to sqlite3_initialize() is an "effective" call if it is 1252** the first time sqlite3_initialize() is invoked during the lifetime of 1253** the process, or if it is the first time sqlite3_initialize() is invoked 1254** following a call to sqlite3_shutdown(). ^(Only an effective call 1255** of sqlite3_initialize() does any initialization. All other calls 1256** are harmless no-ops.)^ 1257** 1258** A call to sqlite3_shutdown() is an "effective" call if it is the first 1259** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1260** an effective call to sqlite3_shutdown() does any deinitialization. 1261** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1262** 1263** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1264** is not. The sqlite3_shutdown() interface must only be called from a 1265** single thread. All open [database connections] must be closed and all 1266** other SQLite resources must be deallocated prior to invoking 1267** sqlite3_shutdown(). 1268** 1269** Among other things, ^sqlite3_initialize() will invoke 1270** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1271** will invoke sqlite3_os_end(). 1272** 1273** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1274** ^If for some reason, sqlite3_initialize() is unable to initialize 1275** the library (perhaps it is unable to allocate a needed resource such 1276** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1277** 1278** ^The sqlite3_initialize() routine is called internally by many other 1279** SQLite interfaces so that an application usually does not need to 1280** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1281** calls sqlite3_initialize() so the SQLite library will be automatically 1282** initialized when [sqlite3_open()] is called if it has not be initialized 1283** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1284** compile-time option, then the automatic calls to sqlite3_initialize() 1285** are omitted and the application must call sqlite3_initialize() directly 1286** prior to using any other SQLite interface. For maximum portability, 1287** it is recommended that applications always invoke sqlite3_initialize() 1288** directly prior to using any other SQLite interface. Future releases 1289** of SQLite may require this. In other words, the behavior exhibited 1290** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1291** default behavior in some future release of SQLite. 1292** 1293** The sqlite3_os_init() routine does operating-system specific 1294** initialization of the SQLite library. The sqlite3_os_end() 1295** routine undoes the effect of sqlite3_os_init(). Typical tasks 1296** performed by these routines include allocation or deallocation 1297** of static resources, initialization of global variables, 1298** setting up a default [sqlite3_vfs] module, or setting up 1299** a default configuration using [sqlite3_config()]. 1300** 1301** The application should never invoke either sqlite3_os_init() 1302** or sqlite3_os_end() directly. The application should only invoke 1303** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1304** interface is called automatically by sqlite3_initialize() and 1305** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1306** implementations for sqlite3_os_init() and sqlite3_os_end() 1307** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1308** When [custom builds | built for other platforms] 1309** (using the [SQLITE_OS_OTHER=1] compile-time 1310** option) the application must supply a suitable implementation for 1311** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1312** implementation of sqlite3_os_init() or sqlite3_os_end() 1313** must return [SQLITE_OK] on success and some other [error code] upon 1314** failure. 1315*/ 1316int sqlite3_initialize(void); 1317int sqlite3_shutdown(void); 1318int sqlite3_os_init(void); 1319int sqlite3_os_end(void); 1320 1321/* 1322** CAPI3REF: Configuring The SQLite Library 1323** 1324** The sqlite3_config() interface is used to make global configuration 1325** changes to SQLite in order to tune SQLite to the specific needs of 1326** the application. The default configuration is recommended for most 1327** applications and so this routine is usually not necessary. It is 1328** provided to support rare applications with unusual needs. 1329** 1330** The sqlite3_config() interface is not threadsafe. The application 1331** must insure that no other SQLite interfaces are invoked by other 1332** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1333** may only be invoked prior to library initialization using 1334** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1335** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1336** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1337** Note, however, that ^sqlite3_config() can be called as part of the 1338** implementation of an application-defined [sqlite3_os_init()]. 1339** 1340** The first argument to sqlite3_config() is an integer 1341** [configuration option] that determines 1342** what property of SQLite is to be configured. Subsequent arguments 1343** vary depending on the [configuration option] 1344** in the first argument. 1345** 1346** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1347** ^If the option is unknown or SQLite is unable to set the option 1348** then this routine returns a non-zero [error code]. 1349*/ 1350int sqlite3_config(int, ...); 1351 1352/* 1353** CAPI3REF: Configure database connections 1354** 1355** The sqlite3_db_config() interface is used to make configuration 1356** changes to a [database connection]. The interface is similar to 1357** [sqlite3_config()] except that the changes apply to a single 1358** [database connection] (specified in the first argument). 1359** 1360** The second argument to sqlite3_db_config(D,V,...) is the 1361** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1362** that indicates what aspect of the [database connection] is being configured. 1363** Subsequent arguments vary depending on the configuration verb. 1364** 1365** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1366** the call is considered successful. 1367*/ 1368int sqlite3_db_config(sqlite3*, int op, ...); 1369 1370/* 1371** CAPI3REF: Memory Allocation Routines 1372** 1373** An instance of this object defines the interface between SQLite 1374** and low-level memory allocation routines. 1375** 1376** This object is used in only one place in the SQLite interface. 1377** A pointer to an instance of this object is the argument to 1378** [sqlite3_config()] when the configuration option is 1379** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1380** By creating an instance of this object 1381** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1382** during configuration, an application can specify an alternative 1383** memory allocation subsystem for SQLite to use for all of its 1384** dynamic memory needs. 1385** 1386** Note that SQLite comes with several [built-in memory allocators] 1387** that are perfectly adequate for the overwhelming majority of applications 1388** and that this object is only useful to a tiny minority of applications 1389** with specialized memory allocation requirements. This object is 1390** also used during testing of SQLite in order to specify an alternative 1391** memory allocator that simulates memory out-of-memory conditions in 1392** order to verify that SQLite recovers gracefully from such 1393** conditions. 1394** 1395** The xMalloc, xRealloc, and xFree methods must work like the 1396** malloc(), realloc() and free() functions from the standard C library. 1397** ^SQLite guarantees that the second argument to 1398** xRealloc is always a value returned by a prior call to xRoundup. 1399** 1400** xSize should return the allocated size of a memory allocation 1401** previously obtained from xMalloc or xRealloc. The allocated size 1402** is always at least as big as the requested size but may be larger. 1403** 1404** The xRoundup method returns what would be the allocated size of 1405** a memory allocation given a particular requested size. Most memory 1406** allocators round up memory allocations at least to the next multiple 1407** of 8. Some allocators round up to a larger multiple or to a power of 2. 1408** Every memory allocation request coming in through [sqlite3_malloc()] 1409** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1410** that causes the corresponding memory allocation to fail. 1411** 1412** The xInit method initializes the memory allocator. For example, 1413** it might allocate any require mutexes or initialize internal data 1414** structures. The xShutdown method is invoked (indirectly) by 1415** [sqlite3_shutdown()] and should deallocate any resources acquired 1416** by xInit. The pAppData pointer is used as the only parameter to 1417** xInit and xShutdown. 1418** 1419** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1420** the xInit method, so the xInit method need not be threadsafe. The 1421** xShutdown method is only called from [sqlite3_shutdown()] so it does 1422** not need to be threadsafe either. For all other methods, SQLite 1423** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1424** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1425** it is by default) and so the methods are automatically serialized. 1426** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1427** methods must be threadsafe or else make their own arrangements for 1428** serialization. 1429** 1430** SQLite will never invoke xInit() more than once without an intervening 1431** call to xShutdown(). 1432*/ 1433typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1434struct sqlite3_mem_methods { 1435 void *(*xMalloc)(int); /* Memory allocation function */ 1436 void (*xFree)(void*); /* Free a prior allocation */ 1437 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1438 int (*xSize)(void*); /* Return the size of an allocation */ 1439 int (*xRoundup)(int); /* Round up request size to allocation size */ 1440 int (*xInit)(void*); /* Initialize the memory allocator */ 1441 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1442 void *pAppData; /* Argument to xInit() and xShutdown() */ 1443}; 1444 1445/* 1446** CAPI3REF: Configuration Options 1447** KEYWORDS: {configuration option} 1448** 1449** These constants are the available integer configuration options that 1450** can be passed as the first argument to the [sqlite3_config()] interface. 1451** 1452** New configuration options may be added in future releases of SQLite. 1453** Existing configuration options might be discontinued. Applications 1454** should check the return code from [sqlite3_config()] to make sure that 1455** the call worked. The [sqlite3_config()] interface will return a 1456** non-zero [error code] if a discontinued or unsupported configuration option 1457** is invoked. 1458** 1459** <dl> 1460** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1461** <dd>There are no arguments to this option. ^This option sets the 1462** [threading mode] to Single-thread. In other words, it disables 1463** all mutexing and puts SQLite into a mode where it can only be used 1464** by a single thread. ^If SQLite is compiled with 1465** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1466** it is not possible to change the [threading mode] from its default 1467** value of Single-thread and so [sqlite3_config()] will return 1468** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1469** configuration option.</dd> 1470** 1471** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1472** <dd>There are no arguments to this option. ^This option sets the 1473** [threading mode] to Multi-thread. In other words, it disables 1474** mutexing on [database connection] and [prepared statement] objects. 1475** The application is responsible for serializing access to 1476** [database connections] and [prepared statements]. But other mutexes 1477** are enabled so that SQLite will be safe to use in a multi-threaded 1478** environment as long as no two threads attempt to use the same 1479** [database connection] at the same time. ^If SQLite is compiled with 1480** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1481** it is not possible to set the Multi-thread [threading mode] and 1482** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1483** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1484** 1485** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1486** <dd>There are no arguments to this option. ^This option sets the 1487** [threading mode] to Serialized. In other words, this option enables 1488** all mutexes including the recursive 1489** mutexes on [database connection] and [prepared statement] objects. 1490** In this mode (which is the default when SQLite is compiled with 1491** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1492** to [database connections] and [prepared statements] so that the 1493** application is free to use the same [database connection] or the 1494** same [prepared statement] in different threads at the same time. 1495** ^If SQLite is compiled with 1496** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1497** it is not possible to set the Serialized [threading mode] and 1498** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1499** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1500** 1501** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1502** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1503** a pointer to an instance of the [sqlite3_mem_methods] structure. 1504** The argument specifies 1505** alternative low-level memory allocation routines to be used in place of 1506** the memory allocation routines built into SQLite.)^ ^SQLite makes 1507** its own private copy of the content of the [sqlite3_mem_methods] structure 1508** before the [sqlite3_config()] call returns.</dd> 1509** 1510** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1511** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1512** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1513** The [sqlite3_mem_methods] 1514** structure is filled with the currently defined memory allocation routines.)^ 1515** This option can be used to overload the default memory allocation 1516** routines with a wrapper that simulations memory allocation failure or 1517** tracks memory usage, for example. </dd> 1518** 1519** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1520** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1521** interpreted as a boolean, which enables or disables the collection of 1522** memory allocation statistics. ^(When memory allocation statistics are 1523** disabled, the following SQLite interfaces become non-operational: 1524** <ul> 1525** <li> [sqlite3_memory_used()] 1526** <li> [sqlite3_memory_highwater()] 1527** <li> [sqlite3_soft_heap_limit64()] 1528** <li> [sqlite3_status()] 1529** </ul>)^ 1530** ^Memory allocation statistics are enabled by default unless SQLite is 1531** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1532** allocation statistics are disabled by default. 1533** </dd> 1534** 1535** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1536** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer 1537** that SQLite can use for scratch memory. ^(There are three arguments 1538** to SQLITE_CONFIG_SCRATCH: A pointer an 8-byte 1539** aligned memory buffer from which the scratch allocations will be 1540** drawn, the size of each scratch allocation (sz), 1541** and the maximum number of scratch allocations (N).)^ 1542** The first argument must be a pointer to an 8-byte aligned buffer 1543** of at least sz*N bytes of memory. 1544** ^SQLite will not use more than one scratch buffers per thread. 1545** ^SQLite will never request a scratch buffer that is more than 6 1546** times the database page size. 1547** ^If SQLite needs needs additional 1548** scratch memory beyond what is provided by this configuration option, then 1549** [sqlite3_malloc()] will be used to obtain the memory needed.<p> 1550** ^When the application provides any amount of scratch memory using 1551** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large 1552** [sqlite3_malloc|heap allocations]. 1553** This can help [Robson proof|prevent memory allocation failures] due to heap 1554** fragmentation in low-memory embedded systems. 1555** </dd> 1556** 1557** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1558** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a static memory buffer 1559** that SQLite can use for the database page cache with the default page 1560** cache implementation. 1561** This configuration should not be used if an application-define page 1562** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2] 1563** configuration option. 1564** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1565** 8-byte aligned 1566** memory, the size of each page buffer (sz), and the number of pages (N). 1567** The sz argument should be the size of the largest database page 1568** (a power of two between 512 and 65536) plus some extra bytes for each 1569** page header. ^The number of extra bytes needed by the page header 1570** can be determined using the [SQLITE_CONFIG_PCACHE_HDRSZ] option 1571** to [sqlite3_config()]. 1572** ^It is harmless, apart from the wasted memory, 1573** for the sz parameter to be larger than necessary. The first 1574** argument should pointer to an 8-byte aligned block of memory that 1575** is at least sz*N bytes of memory, otherwise subsequent behavior is 1576** undefined. 1577** ^SQLite will use the memory provided by the first argument to satisfy its 1578** memory needs for the first N pages that it adds to cache. ^If additional 1579** page cache memory is needed beyond what is provided by this option, then 1580** SQLite goes to [sqlite3_malloc()] for the additional storage space.</dd> 1581** 1582** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1583** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1584** that SQLite will use for all of its dynamic memory allocation needs 1585** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and 1586** [SQLITE_CONFIG_PAGECACHE]. 1587** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1588** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1589** [SQLITE_ERROR] if invoked otherwise. 1590** ^There are three arguments to SQLITE_CONFIG_HEAP: 1591** An 8-byte aligned pointer to the memory, 1592** the number of bytes in the memory buffer, and the minimum allocation size. 1593** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1594** to using its default memory allocator (the system malloc() implementation), 1595** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1596** memory pointer is not NULL then the alternative memory 1597** allocator is engaged to handle all of SQLites memory allocation needs. 1598** The first pointer (the memory pointer) must be aligned to an 8-byte 1599** boundary or subsequent behavior of SQLite will be undefined. 1600** The minimum allocation size is capped at 2**12. Reasonable values 1601** for the minimum allocation size are 2**5 through 2**8.</dd> 1602** 1603** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1604** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1605** pointer to an instance of the [sqlite3_mutex_methods] structure. 1606** The argument specifies alternative low-level mutex routines to be used 1607** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1608** the content of the [sqlite3_mutex_methods] structure before the call to 1609** [sqlite3_config()] returns. ^If SQLite is compiled with 1610** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1611** the entire mutexing subsystem is omitted from the build and hence calls to 1612** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1613** return [SQLITE_ERROR].</dd> 1614** 1615** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1616** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1617** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1618** [sqlite3_mutex_methods] 1619** structure is filled with the currently defined mutex routines.)^ 1620** This option can be used to overload the default mutex allocation 1621** routines with a wrapper used to track mutex usage for performance 1622** profiling or testing, for example. ^If SQLite is compiled with 1623** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1624** the entire mutexing subsystem is omitted from the build and hence calls to 1625** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1626** return [SQLITE_ERROR].</dd> 1627** 1628** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1629** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1630** the default size of lookaside memory on each [database connection]. 1631** The first argument is the 1632** size of each lookaside buffer slot and the second is the number of 1633** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1634** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1635** option to [sqlite3_db_config()] can be used to change the lookaside 1636** configuration on individual connections.)^ </dd> 1637** 1638** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1639** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1640** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1641** the interface to a custom page cache implementation.)^ 1642** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1643** 1644** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1645** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1646** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1647** the current page cache implementation into that object.)^ </dd> 1648** 1649** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1650** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1651** global [error log]. 1652** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1653** function with a call signature of void(*)(void*,int,const char*), 1654** and a pointer to void. ^If the function pointer is not NULL, it is 1655** invoked by [sqlite3_log()] to process each logging event. ^If the 1656** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1657** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1658** passed through as the first parameter to the application-defined logger 1659** function whenever that function is invoked. ^The second parameter to 1660** the logger function is a copy of the first parameter to the corresponding 1661** [sqlite3_log()] call and is intended to be a [result code] or an 1662** [extended result code]. ^The third parameter passed to the logger is 1663** log message after formatting via [sqlite3_snprintf()]. 1664** The SQLite logging interface is not reentrant; the logger function 1665** supplied by the application must not invoke any SQLite interface. 1666** In a multi-threaded application, the application-defined logger 1667** function must be threadsafe. </dd> 1668** 1669** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1670** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1671** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1672** then URI handling is globally disabled.)^ ^If URI handling is globally 1673** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1674** [sqlite3_open16()] or 1675** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1676** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1677** connection is opened. ^If it is globally disabled, filenames are 1678** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1679** database connection is opened. ^(By default, URI handling is globally 1680** disabled. The default value may be changed by compiling with the 1681** [SQLITE_USE_URI] symbol defined.)^ 1682** 1683** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1684** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1685** argument which is interpreted as a boolean in order to enable or disable 1686** the use of covering indices for full table scans in the query optimizer. 1687** ^The default setting is determined 1688** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1689** if that compile-time option is omitted. 1690** The ability to disable the use of covering indices for full table scans 1691** is because some incorrectly coded legacy applications might malfunction 1692** when the optimization is enabled. Providing the ability to 1693** disable the optimization allows the older, buggy application code to work 1694** without change even with newer versions of SQLite. 1695** 1696** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1697** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1698** <dd> These options are obsolete and should not be used by new code. 1699** They are retained for backwards compatibility but are now no-ops. 1700** </dd> 1701** 1702** [[SQLITE_CONFIG_SQLLOG]] 1703** <dt>SQLITE_CONFIG_SQLLOG 1704** <dd>This option is only available if sqlite is compiled with the 1705** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1706** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1707** The second should be of type (void*). The callback is invoked by the library 1708** in three separate circumstances, identified by the value passed as the 1709** fourth parameter. If the fourth parameter is 0, then the database connection 1710** passed as the second argument has just been opened. The third argument 1711** points to a buffer containing the name of the main database file. If the 1712** fourth parameter is 1, then the SQL statement that the third parameter 1713** points to has just been executed. Or, if the fourth parameter is 2, then 1714** the connection being passed as the second parameter is being closed. The 1715** third parameter is passed NULL In this case. An example of using this 1716** configuration option can be seen in the "test_sqllog.c" source file in 1717** the canonical SQLite source tree.</dd> 1718** 1719** [[SQLITE_CONFIG_MMAP_SIZE]] 1720** <dt>SQLITE_CONFIG_MMAP_SIZE 1721** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1722** that are the default mmap size limit (the default setting for 1723** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1724** ^The default setting can be overridden by each database connection using 1725** either the [PRAGMA mmap_size] command, or by using the 1726** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1727** will be silently truncated if necessary so that it does not exceed the 1728** compile-time maximum mmap size set by the 1729** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1730** ^If either argument to this option is negative, then that argument is 1731** changed to its compile-time default. 1732** 1733** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1734** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1735** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1736** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1737** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1738** that specifies the maximum size of the created heap. 1739** </dl> 1740** 1741** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1742** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1743** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1744** is a pointer to an integer and writes into that integer the number of extra 1745** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1746** The amount of extra space required can change depending on the compiler, 1747** target platform, and SQLite version. 1748** </dl> 1749*/ 1750#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1751#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1752#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1753#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1754#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1755#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1756#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1757#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1758#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1759#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1760#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1761/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1762#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1763#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1764#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1765#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1766#define SQLITE_CONFIG_URI 17 /* int */ 1767#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1768#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1769#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1770#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1771#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1772#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1773#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1774 1775/* 1776** CAPI3REF: Database Connection Configuration Options 1777** 1778** These constants are the available integer configuration options that 1779** can be passed as the second argument to the [sqlite3_db_config()] interface. 1780** 1781** New configuration options may be added in future releases of SQLite. 1782** Existing configuration options might be discontinued. Applications 1783** should check the return code from [sqlite3_db_config()] to make sure that 1784** the call worked. ^The [sqlite3_db_config()] interface will return a 1785** non-zero [error code] if a discontinued or unsupported configuration option 1786** is invoked. 1787** 1788** <dl> 1789** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1790** <dd> ^This option takes three additional arguments that determine the 1791** [lookaside memory allocator] configuration for the [database connection]. 1792** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1793** pointer to a memory buffer to use for lookaside memory. 1794** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1795** may be NULL in which case SQLite will allocate the 1796** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1797** size of each lookaside buffer slot. ^The third argument is the number of 1798** slots. The size of the buffer in the first argument must be greater than 1799** or equal to the product of the second and third arguments. The buffer 1800** must be aligned to an 8-byte boundary. ^If the second argument to 1801** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1802** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1803** configuration for a database connection can only be changed when that 1804** connection is not currently using lookaside memory, or in other words 1805** when the "current value" returned by 1806** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1807** Any attempt to change the lookaside memory configuration when lookaside 1808** memory is in use leaves the configuration unchanged and returns 1809** [SQLITE_BUSY].)^</dd> 1810** 1811** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1812** <dd> ^This option is used to enable or disable the enforcement of 1813** [foreign key constraints]. There should be two additional arguments. 1814** The first argument is an integer which is 0 to disable FK enforcement, 1815** positive to enable FK enforcement or negative to leave FK enforcement 1816** unchanged. The second parameter is a pointer to an integer into which 1817** is written 0 or 1 to indicate whether FK enforcement is off or on 1818** following this call. The second parameter may be a NULL pointer, in 1819** which case the FK enforcement setting is not reported back. </dd> 1820** 1821** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1822** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1823** There should be two additional arguments. 1824** The first argument is an integer which is 0 to disable triggers, 1825** positive to enable triggers or negative to leave the setting unchanged. 1826** The second parameter is a pointer to an integer into which 1827** is written 0 or 1 to indicate whether triggers are disabled or enabled 1828** following this call. The second parameter may be a NULL pointer, in 1829** which case the trigger setting is not reported back. </dd> 1830** 1831** </dl> 1832*/ 1833#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1834#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1835#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1836 1837 1838/* 1839** CAPI3REF: Enable Or Disable Extended Result Codes 1840** 1841** ^The sqlite3_extended_result_codes() routine enables or disables the 1842** [extended result codes] feature of SQLite. ^The extended result 1843** codes are disabled by default for historical compatibility. 1844*/ 1845int sqlite3_extended_result_codes(sqlite3*, int onoff); 1846 1847/* 1848** CAPI3REF: Last Insert Rowid 1849** 1850** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 1851** has a unique 64-bit signed 1852** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1853** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1854** names are not also used by explicitly declared columns. ^If 1855** the table has a column of type [INTEGER PRIMARY KEY] then that column 1856** is another alias for the rowid. 1857** 1858** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the 1859** most recent successful [INSERT] into a rowid table or [virtual table] 1860** on database connection D. 1861** ^Inserts into [WITHOUT ROWID] tables are not recorded. 1862** ^If no successful [INSERT]s into rowid tables 1863** have ever occurred on the database connection D, 1864** then sqlite3_last_insert_rowid(D) returns zero. 1865** 1866** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1867** method, then this routine will return the [rowid] of the inserted 1868** row as long as the trigger or virtual table method is running. 1869** But once the trigger or virtual table method ends, the value returned 1870** by this routine reverts to what it was before the trigger or virtual 1871** table method began.)^ 1872** 1873** ^An [INSERT] that fails due to a constraint violation is not a 1874** successful [INSERT] and does not change the value returned by this 1875** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1876** and INSERT OR ABORT make no changes to the return value of this 1877** routine when their insertion fails. ^(When INSERT OR REPLACE 1878** encounters a constraint violation, it does not fail. The 1879** INSERT continues to completion after deleting rows that caused 1880** the constraint problem so INSERT OR REPLACE will always change 1881** the return value of this interface.)^ 1882** 1883** ^For the purposes of this routine, an [INSERT] is considered to 1884** be successful even if it is subsequently rolled back. 1885** 1886** This function is accessible to SQL statements via the 1887** [last_insert_rowid() SQL function]. 1888** 1889** If a separate thread performs a new [INSERT] on the same 1890** database connection while the [sqlite3_last_insert_rowid()] 1891** function is running and thus changes the last insert [rowid], 1892** then the value returned by [sqlite3_last_insert_rowid()] is 1893** unpredictable and might not equal either the old or the new 1894** last insert [rowid]. 1895*/ 1896sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1897 1898/* 1899** CAPI3REF: Count The Number Of Rows Modified 1900** 1901** ^This function returns the number of rows modified, inserted or 1902** deleted by the most recently completed INSERT, UPDATE or DELETE 1903** statement on the database connection specified by the only parameter. 1904** ^Executing any other type of SQL statement does not modify the value 1905** returned by this function. 1906** 1907** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 1908** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 1909** [foreign key actions] or [REPLACE] constraint resolution are not counted. 1910** 1911** Changes to a view that are intercepted by 1912** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 1913** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 1914** DELETE statement run on a view is always zero. Only changes made to real 1915** tables are counted. 1916** 1917** Things are more complicated if the sqlite3_changes() function is 1918** executed while a trigger program is running. This may happen if the 1919** program uses the [changes() SQL function], or if some other callback 1920** function invokes sqlite3_changes() directly. Essentially: 1921** 1922** <ul> 1923** <li> ^(Before entering a trigger program the value returned by 1924** sqlite3_changes() function is saved. After the trigger program 1925** has finished, the original value is restored.)^ 1926** 1927** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 1928** statement sets the value returned by sqlite3_changes() 1929** upon completion as normal. Of course, this value will not include 1930** any changes performed by sub-triggers, as the sqlite3_changes() 1931** value will be saved and restored after each sub-trigger has run.)^ 1932** </ul> 1933** 1934** ^This means that if the changes() SQL function (or similar) is used 1935** by the first INSERT, UPDATE or DELETE statement within a trigger, it 1936** returns the value as set when the calling statement began executing. 1937** ^If it is used by the second or subsequent such statement within a trigger 1938** program, the value returned reflects the number of rows modified by the 1939** previous INSERT, UPDATE or DELETE statement within the same trigger. 1940** 1941** See also the [sqlite3_total_changes()] interface, the 1942** [count_changes pragma], and the [changes() SQL function]. 1943** 1944** If a separate thread makes changes on the same database connection 1945** while [sqlite3_changes()] is running then the value returned 1946** is unpredictable and not meaningful. 1947*/ 1948int sqlite3_changes(sqlite3*); 1949 1950/* 1951** CAPI3REF: Total Number Of Rows Modified 1952** 1953** ^This function returns the total number of rows inserted, modified or 1954** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 1955** since the database connection was opened, including those executed as 1956** part of trigger programs. ^Executing any other type of SQL statement 1957** does not affect the value returned by sqlite3_total_changes(). 1958** 1959** ^Changes made as part of [foreign key actions] are included in the 1960** count, but those made as part of REPLACE constraint resolution are 1961** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 1962** are not counted. 1963** 1964** See also the [sqlite3_changes()] interface, the 1965** [count_changes pragma], and the [total_changes() SQL function]. 1966** 1967** If a separate thread makes changes on the same database connection 1968** while [sqlite3_total_changes()] is running then the value 1969** returned is unpredictable and not meaningful. 1970*/ 1971int sqlite3_total_changes(sqlite3*); 1972 1973/* 1974** CAPI3REF: Interrupt A Long-Running Query 1975** 1976** ^This function causes any pending database operation to abort and 1977** return at its earliest opportunity. This routine is typically 1978** called in response to a user action such as pressing "Cancel" 1979** or Ctrl-C where the user wants a long query operation to halt 1980** immediately. 1981** 1982** ^It is safe to call this routine from a thread different from the 1983** thread that is currently running the database operation. But it 1984** is not safe to call this routine with a [database connection] that 1985** is closed or might close before sqlite3_interrupt() returns. 1986** 1987** ^If an SQL operation is very nearly finished at the time when 1988** sqlite3_interrupt() is called, then it might not have an opportunity 1989** to be interrupted and might continue to completion. 1990** 1991** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1992** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1993** that is inside an explicit transaction, then the entire transaction 1994** will be rolled back automatically. 1995** 1996** ^The sqlite3_interrupt(D) call is in effect until all currently running 1997** SQL statements on [database connection] D complete. ^Any new SQL statements 1998** that are started after the sqlite3_interrupt() call and before the 1999** running statements reaches zero are interrupted as if they had been 2000** running prior to the sqlite3_interrupt() call. ^New SQL statements 2001** that are started after the running statement count reaches zero are 2002** not effected by the sqlite3_interrupt(). 2003** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2004** SQL statements is a no-op and has no effect on SQL statements 2005** that are started after the sqlite3_interrupt() call returns. 2006** 2007** If the database connection closes while [sqlite3_interrupt()] 2008** is running then bad things will likely happen. 2009*/ 2010void sqlite3_interrupt(sqlite3*); 2011 2012/* 2013** CAPI3REF: Determine If An SQL Statement Is Complete 2014** 2015** These routines are useful during command-line input to determine if the 2016** currently entered text seems to form a complete SQL statement or 2017** if additional input is needed before sending the text into 2018** SQLite for parsing. ^These routines return 1 if the input string 2019** appears to be a complete SQL statement. ^A statement is judged to be 2020** complete if it ends with a semicolon token and is not a prefix of a 2021** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2022** string literals or quoted identifier names or comments are not 2023** independent tokens (they are part of the token in which they are 2024** embedded) and thus do not count as a statement terminator. ^Whitespace 2025** and comments that follow the final semicolon are ignored. 2026** 2027** ^These routines return 0 if the statement is incomplete. ^If a 2028** memory allocation fails, then SQLITE_NOMEM is returned. 2029** 2030** ^These routines do not parse the SQL statements thus 2031** will not detect syntactically incorrect SQL. 2032** 2033** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2034** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2035** automatically by sqlite3_complete16(). If that initialization fails, 2036** then the return value from sqlite3_complete16() will be non-zero 2037** regardless of whether or not the input SQL is complete.)^ 2038** 2039** The input to [sqlite3_complete()] must be a zero-terminated 2040** UTF-8 string. 2041** 2042** The input to [sqlite3_complete16()] must be a zero-terminated 2043** UTF-16 string in native byte order. 2044*/ 2045int sqlite3_complete(const char *sql); 2046int sqlite3_complete16(const void *sql); 2047 2048/* 2049** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2050** KEYWORDS: {busy-handler callback} {busy handler} 2051** 2052** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2053** that might be invoked with argument P whenever 2054** an attempt is made to access a database table associated with 2055** [database connection] D when another thread 2056** or process has the table locked. 2057** The sqlite3_busy_handler() interface is used to implement 2058** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2059** 2060** ^If the busy callback is NULL, then [SQLITE_BUSY] 2061** is returned immediately upon encountering the lock. ^If the busy callback 2062** is not NULL, then the callback might be invoked with two arguments. 2063** 2064** ^The first argument to the busy handler is a copy of the void* pointer which 2065** is the third argument to sqlite3_busy_handler(). ^The second argument to 2066** the busy handler callback is the number of times that the busy handler has 2067** been invoked previously for the same locking event. ^If the 2068** busy callback returns 0, then no additional attempts are made to 2069** access the database and [SQLITE_BUSY] is returned 2070** to the application. 2071** ^If the callback returns non-zero, then another attempt 2072** is made to access the database and the cycle repeats. 2073** 2074** The presence of a busy handler does not guarantee that it will be invoked 2075** when there is lock contention. ^If SQLite determines that invoking the busy 2076** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2077** to the application instead of invoking the 2078** busy handler. 2079** Consider a scenario where one process is holding a read lock that 2080** it is trying to promote to a reserved lock and 2081** a second process is holding a reserved lock that it is trying 2082** to promote to an exclusive lock. The first process cannot proceed 2083** because it is blocked by the second and the second process cannot 2084** proceed because it is blocked by the first. If both processes 2085** invoke the busy handlers, neither will make any progress. Therefore, 2086** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2087** will induce the first process to release its read lock and allow 2088** the second process to proceed. 2089** 2090** ^The default busy callback is NULL. 2091** 2092** ^(There can only be a single busy handler defined for each 2093** [database connection]. Setting a new busy handler clears any 2094** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2095** or evaluating [PRAGMA busy_timeout=N] will change the 2096** busy handler and thus clear any previously set busy handler. 2097** 2098** The busy callback should not take any actions which modify the 2099** database connection that invoked the busy handler. In other words, 2100** the busy handler is not reentrant. Any such actions 2101** result in undefined behavior. 2102** 2103** A busy handler must not close the database connection 2104** or [prepared statement] that invoked the busy handler. 2105*/ 2106int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 2107 2108/* 2109** CAPI3REF: Set A Busy Timeout 2110** 2111** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2112** for a specified amount of time when a table is locked. ^The handler 2113** will sleep multiple times until at least "ms" milliseconds of sleeping 2114** have accumulated. ^After at least "ms" milliseconds of sleeping, 2115** the handler returns 0 which causes [sqlite3_step()] to return 2116** [SQLITE_BUSY]. 2117** 2118** ^Calling this routine with an argument less than or equal to zero 2119** turns off all busy handlers. 2120** 2121** ^(There can only be a single busy handler for a particular 2122** [database connection] at any given moment. If another busy handler 2123** was defined (using [sqlite3_busy_handler()]) prior to calling 2124** this routine, that other busy handler is cleared.)^ 2125** 2126** See also: [PRAGMA busy_timeout] 2127*/ 2128int sqlite3_busy_timeout(sqlite3*, int ms); 2129 2130/* 2131** CAPI3REF: Convenience Routines For Running Queries 2132** 2133** This is a legacy interface that is preserved for backwards compatibility. 2134** Use of this interface is not recommended. 2135** 2136** Definition: A <b>result table</b> is memory data structure created by the 2137** [sqlite3_get_table()] interface. A result table records the 2138** complete query results from one or more queries. 2139** 2140** The table conceptually has a number of rows and columns. But 2141** these numbers are not part of the result table itself. These 2142** numbers are obtained separately. Let N be the number of rows 2143** and M be the number of columns. 2144** 2145** A result table is an array of pointers to zero-terminated UTF-8 strings. 2146** There are (N+1)*M elements in the array. The first M pointers point 2147** to zero-terminated strings that contain the names of the columns. 2148** The remaining entries all point to query results. NULL values result 2149** in NULL pointers. All other values are in their UTF-8 zero-terminated 2150** string representation as returned by [sqlite3_column_text()]. 2151** 2152** A result table might consist of one or more memory allocations. 2153** It is not safe to pass a result table directly to [sqlite3_free()]. 2154** A result table should be deallocated using [sqlite3_free_table()]. 2155** 2156** ^(As an example of the result table format, suppose a query result 2157** is as follows: 2158** 2159** <blockquote><pre> 2160** Name | Age 2161** ----------------------- 2162** Alice | 43 2163** Bob | 28 2164** Cindy | 21 2165** </pre></blockquote> 2166** 2167** There are two column (M==2) and three rows (N==3). Thus the 2168** result table has 8 entries. Suppose the result table is stored 2169** in an array names azResult. Then azResult holds this content: 2170** 2171** <blockquote><pre> 2172** azResult[0] = "Name"; 2173** azResult[1] = "Age"; 2174** azResult[2] = "Alice"; 2175** azResult[3] = "43"; 2176** azResult[4] = "Bob"; 2177** azResult[5] = "28"; 2178** azResult[6] = "Cindy"; 2179** azResult[7] = "21"; 2180** </pre></blockquote>)^ 2181** 2182** ^The sqlite3_get_table() function evaluates one or more 2183** semicolon-separated SQL statements in the zero-terminated UTF-8 2184** string of its 2nd parameter and returns a result table to the 2185** pointer given in its 3rd parameter. 2186** 2187** After the application has finished with the result from sqlite3_get_table(), 2188** it must pass the result table pointer to sqlite3_free_table() in order to 2189** release the memory that was malloced. Because of the way the 2190** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2191** function must not try to call [sqlite3_free()] directly. Only 2192** [sqlite3_free_table()] is able to release the memory properly and safely. 2193** 2194** The sqlite3_get_table() interface is implemented as a wrapper around 2195** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2196** to any internal data structures of SQLite. It uses only the public 2197** interface defined here. As a consequence, errors that occur in the 2198** wrapper layer outside of the internal [sqlite3_exec()] call are not 2199** reflected in subsequent calls to [sqlite3_errcode()] or 2200** [sqlite3_errmsg()]. 2201*/ 2202int sqlite3_get_table( 2203 sqlite3 *db, /* An open database */ 2204 const char *zSql, /* SQL to be evaluated */ 2205 char ***pazResult, /* Results of the query */ 2206 int *pnRow, /* Number of result rows written here */ 2207 int *pnColumn, /* Number of result columns written here */ 2208 char **pzErrmsg /* Error msg written here */ 2209); 2210void sqlite3_free_table(char **result); 2211 2212/* 2213** CAPI3REF: Formatted String Printing Functions 2214** 2215** These routines are work-alikes of the "printf()" family of functions 2216** from the standard C library. 2217** 2218** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2219** results into memory obtained from [sqlite3_malloc()]. 2220** The strings returned by these two routines should be 2221** released by [sqlite3_free()]. ^Both routines return a 2222** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2223** memory to hold the resulting string. 2224** 2225** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2226** the standard C library. The result is written into the 2227** buffer supplied as the second parameter whose size is given by 2228** the first parameter. Note that the order of the 2229** first two parameters is reversed from snprintf().)^ This is an 2230** historical accident that cannot be fixed without breaking 2231** backwards compatibility. ^(Note also that sqlite3_snprintf() 2232** returns a pointer to its buffer instead of the number of 2233** characters actually written into the buffer.)^ We admit that 2234** the number of characters written would be a more useful return 2235** value but we cannot change the implementation of sqlite3_snprintf() 2236** now without breaking compatibility. 2237** 2238** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2239** guarantees that the buffer is always zero-terminated. ^The first 2240** parameter "n" is the total size of the buffer, including space for 2241** the zero terminator. So the longest string that can be completely 2242** written will be n-1 characters. 2243** 2244** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2245** 2246** These routines all implement some additional formatting 2247** options that are useful for constructing SQL statements. 2248** All of the usual printf() formatting options apply. In addition, there 2249** is are "%q", "%Q", and "%z" options. 2250** 2251** ^(The %q option works like %s in that it substitutes a nul-terminated 2252** string from the argument list. But %q also doubles every '\'' character. 2253** %q is designed for use inside a string literal.)^ By doubling each '\'' 2254** character it escapes that character and allows it to be inserted into 2255** the string. 2256** 2257** For example, assume the string variable zText contains text as follows: 2258** 2259** <blockquote><pre> 2260** char *zText = "It's a happy day!"; 2261** </pre></blockquote> 2262** 2263** One can use this text in an SQL statement as follows: 2264** 2265** <blockquote><pre> 2266** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2267** sqlite3_exec(db, zSQL, 0, 0, 0); 2268** sqlite3_free(zSQL); 2269** </pre></blockquote> 2270** 2271** Because the %q format string is used, the '\'' character in zText 2272** is escaped and the SQL generated is as follows: 2273** 2274** <blockquote><pre> 2275** INSERT INTO table1 VALUES('It''s a happy day!') 2276** </pre></blockquote> 2277** 2278** This is correct. Had we used %s instead of %q, the generated SQL 2279** would have looked like this: 2280** 2281** <blockquote><pre> 2282** INSERT INTO table1 VALUES('It's a happy day!'); 2283** </pre></blockquote> 2284** 2285** This second example is an SQL syntax error. As a general rule you should 2286** always use %q instead of %s when inserting text into a string literal. 2287** 2288** ^(The %Q option works like %q except it also adds single quotes around 2289** the outside of the total string. Additionally, if the parameter in the 2290** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2291** single quotes).)^ So, for example, one could say: 2292** 2293** <blockquote><pre> 2294** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2295** sqlite3_exec(db, zSQL, 0, 0, 0); 2296** sqlite3_free(zSQL); 2297** </pre></blockquote> 2298** 2299** The code above will render a correct SQL statement in the zSQL 2300** variable even if the zText variable is a NULL pointer. 2301** 2302** ^(The "%z" formatting option works like "%s" but with the 2303** addition that after the string has been read and copied into 2304** the result, [sqlite3_free()] is called on the input string.)^ 2305*/ 2306char *sqlite3_mprintf(const char*,...); 2307char *sqlite3_vmprintf(const char*, va_list); 2308char *sqlite3_snprintf(int,char*,const char*, ...); 2309char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2310 2311/* 2312** CAPI3REF: Memory Allocation Subsystem 2313** 2314** The SQLite core uses these three routines for all of its own 2315** internal memory allocation needs. "Core" in the previous sentence 2316** does not include operating-system specific VFS implementation. The 2317** Windows VFS uses native malloc() and free() for some operations. 2318** 2319** ^The sqlite3_malloc() routine returns a pointer to a block 2320** of memory at least N bytes in length, where N is the parameter. 2321** ^If sqlite3_malloc() is unable to obtain sufficient free 2322** memory, it returns a NULL pointer. ^If the parameter N to 2323** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2324** a NULL pointer. 2325** 2326** ^The sqlite3_malloc64(N) routine works just like 2327** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2328** of a signed 32-bit integer. 2329** 2330** ^Calling sqlite3_free() with a pointer previously returned 2331** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2332** that it might be reused. ^The sqlite3_free() routine is 2333** a no-op if is called with a NULL pointer. Passing a NULL pointer 2334** to sqlite3_free() is harmless. After being freed, memory 2335** should neither be read nor written. Even reading previously freed 2336** memory might result in a segmentation fault or other severe error. 2337** Memory corruption, a segmentation fault, or other severe error 2338** might result if sqlite3_free() is called with a non-NULL pointer that 2339** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2340** 2341** ^The sqlite3_realloc(X,N) interface attempts to resize a 2342** prior memory allocation X to be at least N bytes. 2343** ^If the X parameter to sqlite3_realloc(X,N) 2344** is a NULL pointer then its behavior is identical to calling 2345** sqlite3_malloc(N). 2346** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2347** negative then the behavior is exactly the same as calling 2348** sqlite3_free(X). 2349** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2350** of at least N bytes in size or NULL if insufficient memory is available. 2351** ^If M is the size of the prior allocation, then min(N,M) bytes 2352** of the prior allocation are copied into the beginning of buffer returned 2353** by sqlite3_realloc(X,N) and the prior allocation is freed. 2354** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2355** prior allocation is not freed. 2356** 2357** ^The sqlite3_realloc64(X,N) interfaces works the same as 2358** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2359** of a 32-bit signed integer. 2360** 2361** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2362** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2363** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2364** ^The value returned by sqlite3_msize(X) might be larger than the number 2365** of bytes requested when X was allocated. ^If X is a NULL pointer then 2366** sqlite3_msize(X) returns zero. If X points to something that is not 2367** the beginning of memory allocation, or if it points to a formerly 2368** valid memory allocation that has now been freed, then the behavior 2369** of sqlite3_msize(X) is undefined and possibly harmful. 2370** 2371** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2372** sqlite3_malloc64(), and sqlite3_realloc64() 2373** is always aligned to at least an 8 byte boundary, or to a 2374** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2375** option is used. 2376** 2377** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2378** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2379** implementation of these routines to be omitted. That capability 2380** is no longer provided. Only built-in memory allocators can be used. 2381** 2382** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2383** the system malloc() and free() directly when converting 2384** filenames between the UTF-8 encoding used by SQLite 2385** and whatever filename encoding is used by the particular Windows 2386** installation. Memory allocation errors were detected, but 2387** they were reported back as [SQLITE_CANTOPEN] or 2388** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2389** 2390** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2391** must be either NULL or else pointers obtained from a prior 2392** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2393** not yet been released. 2394** 2395** The application must not read or write any part of 2396** a block of memory after it has been released using 2397** [sqlite3_free()] or [sqlite3_realloc()]. 2398*/ 2399void *sqlite3_malloc(int); 2400void *sqlite3_malloc64(sqlite3_uint64); 2401void *sqlite3_realloc(void*, int); 2402void *sqlite3_realloc64(void*, sqlite3_uint64); 2403void sqlite3_free(void*); 2404sqlite3_uint64 sqlite3_msize(void*); 2405 2406/* 2407** CAPI3REF: Memory Allocator Statistics 2408** 2409** SQLite provides these two interfaces for reporting on the status 2410** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2411** routines, which form the built-in memory allocation subsystem. 2412** 2413** ^The [sqlite3_memory_used()] routine returns the number of bytes 2414** of memory currently outstanding (malloced but not freed). 2415** ^The [sqlite3_memory_highwater()] routine returns the maximum 2416** value of [sqlite3_memory_used()] since the high-water mark 2417** was last reset. ^The values returned by [sqlite3_memory_used()] and 2418** [sqlite3_memory_highwater()] include any overhead 2419** added by SQLite in its implementation of [sqlite3_malloc()], 2420** but not overhead added by the any underlying system library 2421** routines that [sqlite3_malloc()] may call. 2422** 2423** ^The memory high-water mark is reset to the current value of 2424** [sqlite3_memory_used()] if and only if the parameter to 2425** [sqlite3_memory_highwater()] is true. ^The value returned 2426** by [sqlite3_memory_highwater(1)] is the high-water mark 2427** prior to the reset. 2428*/ 2429sqlite3_int64 sqlite3_memory_used(void); 2430sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2431 2432/* 2433** CAPI3REF: Pseudo-Random Number Generator 2434** 2435** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2436** select random [ROWID | ROWIDs] when inserting new records into a table that 2437** already uses the largest possible [ROWID]. The PRNG is also used for 2438** the build-in random() and randomblob() SQL functions. This interface allows 2439** applications to access the same PRNG for other purposes. 2440** 2441** ^A call to this routine stores N bytes of randomness into buffer P. 2442** ^The P parameter can be a NULL pointer. 2443** 2444** ^If this routine has not been previously called or if the previous 2445** call had N less than one or a NULL pointer for P, then the PRNG is 2446** seeded using randomness obtained from the xRandomness method of 2447** the default [sqlite3_vfs] object. 2448** ^If the previous call to this routine had an N of 1 or more and a 2449** non-NULL P then the pseudo-randomness is generated 2450** internally and without recourse to the [sqlite3_vfs] xRandomness 2451** method. 2452*/ 2453void sqlite3_randomness(int N, void *P); 2454 2455/* 2456** CAPI3REF: Compile-Time Authorization Callbacks 2457** 2458** ^This routine registers an authorizer callback with a particular 2459** [database connection], supplied in the first argument. 2460** ^The authorizer callback is invoked as SQL statements are being compiled 2461** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2462** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2463** points during the compilation process, as logic is being created 2464** to perform various actions, the authorizer callback is invoked to 2465** see if those actions are allowed. ^The authorizer callback should 2466** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2467** specific action but allow the SQL statement to continue to be 2468** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2469** rejected with an error. ^If the authorizer callback returns 2470** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2471** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2472** the authorizer will fail with an error message. 2473** 2474** When the callback returns [SQLITE_OK], that means the operation 2475** requested is ok. ^When the callback returns [SQLITE_DENY], the 2476** [sqlite3_prepare_v2()] or equivalent call that triggered the 2477** authorizer will fail with an error message explaining that 2478** access is denied. 2479** 2480** ^The first parameter to the authorizer callback is a copy of the third 2481** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2482** to the callback is an integer [SQLITE_COPY | action code] that specifies 2483** the particular action to be authorized. ^The third through sixth parameters 2484** to the callback are zero-terminated strings that contain additional 2485** details about the action to be authorized. 2486** 2487** ^If the action code is [SQLITE_READ] 2488** and the callback returns [SQLITE_IGNORE] then the 2489** [prepared statement] statement is constructed to substitute 2490** a NULL value in place of the table column that would have 2491** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2492** return can be used to deny an untrusted user access to individual 2493** columns of a table. 2494** ^If the action code is [SQLITE_DELETE] and the callback returns 2495** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2496** [truncate optimization] is disabled and all rows are deleted individually. 2497** 2498** An authorizer is used when [sqlite3_prepare | preparing] 2499** SQL statements from an untrusted source, to ensure that the SQL statements 2500** do not try to access data they are not allowed to see, or that they do not 2501** try to execute malicious statements that damage the database. For 2502** example, an application may allow a user to enter arbitrary 2503** SQL queries for evaluation by a database. But the application does 2504** not want the user to be able to make arbitrary changes to the 2505** database. An authorizer could then be put in place while the 2506** user-entered SQL is being [sqlite3_prepare | prepared] that 2507** disallows everything except [SELECT] statements. 2508** 2509** Applications that need to process SQL from untrusted sources 2510** might also consider lowering resource limits using [sqlite3_limit()] 2511** and limiting database size using the [max_page_count] [PRAGMA] 2512** in addition to using an authorizer. 2513** 2514** ^(Only a single authorizer can be in place on a database connection 2515** at a time. Each call to sqlite3_set_authorizer overrides the 2516** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2517** The authorizer is disabled by default. 2518** 2519** The authorizer callback must not do anything that will modify 2520** the database connection that invoked the authorizer callback. 2521** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2522** database connections for the meaning of "modify" in this paragraph. 2523** 2524** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2525** statement might be re-prepared during [sqlite3_step()] due to a 2526** schema change. Hence, the application should ensure that the 2527** correct authorizer callback remains in place during the [sqlite3_step()]. 2528** 2529** ^Note that the authorizer callback is invoked only during 2530** [sqlite3_prepare()] or its variants. Authorization is not 2531** performed during statement evaluation in [sqlite3_step()], unless 2532** as stated in the previous paragraph, sqlite3_step() invokes 2533** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2534*/ 2535int sqlite3_set_authorizer( 2536 sqlite3*, 2537 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2538 void *pUserData 2539); 2540 2541/* 2542** CAPI3REF: Authorizer Return Codes 2543** 2544** The [sqlite3_set_authorizer | authorizer callback function] must 2545** return either [SQLITE_OK] or one of these two constants in order 2546** to signal SQLite whether or not the action is permitted. See the 2547** [sqlite3_set_authorizer | authorizer documentation] for additional 2548** information. 2549** 2550** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2551** returned from the [sqlite3_vtab_on_conflict()] interface. 2552*/ 2553#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2554#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2555 2556/* 2557** CAPI3REF: Authorizer Action Codes 2558** 2559** The [sqlite3_set_authorizer()] interface registers a callback function 2560** that is invoked to authorize certain SQL statement actions. The 2561** second parameter to the callback is an integer code that specifies 2562** what action is being authorized. These are the integer action codes that 2563** the authorizer callback may be passed. 2564** 2565** These action code values signify what kind of operation is to be 2566** authorized. The 3rd and 4th parameters to the authorization 2567** callback function will be parameters or NULL depending on which of these 2568** codes is used as the second parameter. ^(The 5th parameter to the 2569** authorizer callback is the name of the database ("main", "temp", 2570** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2571** is the name of the inner-most trigger or view that is responsible for 2572** the access attempt or NULL if this access attempt is directly from 2573** top-level SQL code. 2574*/ 2575/******************************************* 3rd ************ 4th ***********/ 2576#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2577#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2578#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2579#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2580#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2581#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2582#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2583#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2584#define SQLITE_DELETE 9 /* Table Name NULL */ 2585#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2586#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2587#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2588#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2589#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2590#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2591#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2592#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2593#define SQLITE_INSERT 18 /* Table Name NULL */ 2594#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2595#define SQLITE_READ 20 /* Table Name Column Name */ 2596#define SQLITE_SELECT 21 /* NULL NULL */ 2597#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2598#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2599#define SQLITE_ATTACH 24 /* Filename NULL */ 2600#define SQLITE_DETACH 25 /* Database Name NULL */ 2601#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2602#define SQLITE_REINDEX 27 /* Index Name NULL */ 2603#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2604#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2605#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2606#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2607#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2608#define SQLITE_COPY 0 /* No longer used */ 2609#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2610 2611/* 2612** CAPI3REF: Tracing And Profiling Functions 2613** 2614** These routines register callback functions that can be used for 2615** tracing and profiling the execution of SQL statements. 2616** 2617** ^The callback function registered by sqlite3_trace() is invoked at 2618** various times when an SQL statement is being run by [sqlite3_step()]. 2619** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2620** SQL statement text as the statement first begins executing. 2621** ^(Additional sqlite3_trace() callbacks might occur 2622** as each triggered subprogram is entered. The callbacks for triggers 2623** contain a UTF-8 SQL comment that identifies the trigger.)^ 2624** 2625** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2626** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2627** 2628** ^The callback function registered by sqlite3_profile() is invoked 2629** as each SQL statement finishes. ^The profile callback contains 2630** the original statement text and an estimate of wall-clock time 2631** of how long that statement took to run. ^The profile callback 2632** time is in units of nanoseconds, however the current implementation 2633** is only capable of millisecond resolution so the six least significant 2634** digits in the time are meaningless. Future versions of SQLite 2635** might provide greater resolution on the profiler callback. The 2636** sqlite3_profile() function is considered experimental and is 2637** subject to change in future versions of SQLite. 2638*/ 2639void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2640SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2641 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2642 2643/* 2644** CAPI3REF: Query Progress Callbacks 2645** 2646** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2647** function X to be invoked periodically during long running calls to 2648** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2649** database connection D. An example use for this 2650** interface is to keep a GUI updated during a large query. 2651** 2652** ^The parameter P is passed through as the only parameter to the 2653** callback function X. ^The parameter N is the approximate number of 2654** [virtual machine instructions] that are evaluated between successive 2655** invocations of the callback X. ^If N is less than one then the progress 2656** handler is disabled. 2657** 2658** ^Only a single progress handler may be defined at one time per 2659** [database connection]; setting a new progress handler cancels the 2660** old one. ^Setting parameter X to NULL disables the progress handler. 2661** ^The progress handler is also disabled by setting N to a value less 2662** than 1. 2663** 2664** ^If the progress callback returns non-zero, the operation is 2665** interrupted. This feature can be used to implement a 2666** "Cancel" button on a GUI progress dialog box. 2667** 2668** The progress handler callback must not do anything that will modify 2669** the database connection that invoked the progress handler. 2670** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2671** database connections for the meaning of "modify" in this paragraph. 2672** 2673*/ 2674void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2675 2676/* 2677** CAPI3REF: Opening A New Database Connection 2678** 2679** ^These routines open an SQLite database file as specified by the 2680** filename argument. ^The filename argument is interpreted as UTF-8 for 2681** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2682** order for sqlite3_open16(). ^(A [database connection] handle is usually 2683** returned in *ppDb, even if an error occurs. The only exception is that 2684** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2685** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2686** object.)^ ^(If the database is opened (and/or created) successfully, then 2687** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2688** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2689** an English language description of the error following a failure of any 2690** of the sqlite3_open() routines. 2691** 2692** ^The default encoding will be UTF-8 for databases created using 2693** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 2694** created using sqlite3_open16() will be UTF-16 in the native byte order. 2695** 2696** Whether or not an error occurs when it is opened, resources 2697** associated with the [database connection] handle should be released by 2698** passing it to [sqlite3_close()] when it is no longer required. 2699** 2700** The sqlite3_open_v2() interface works like sqlite3_open() 2701** except that it accepts two additional parameters for additional control 2702** over the new database connection. ^(The flags parameter to 2703** sqlite3_open_v2() can take one of 2704** the following three values, optionally combined with the 2705** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2706** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2707** 2708** <dl> 2709** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2710** <dd>The database is opened in read-only mode. If the database does not 2711** already exist, an error is returned.</dd>)^ 2712** 2713** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2714** <dd>The database is opened for reading and writing if possible, or reading 2715** only if the file is write protected by the operating system. In either 2716** case the database must already exist, otherwise an error is returned.</dd>)^ 2717** 2718** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2719** <dd>The database is opened for reading and writing, and is created if 2720** it does not already exist. This is the behavior that is always used for 2721** sqlite3_open() and sqlite3_open16().</dd>)^ 2722** </dl> 2723** 2724** If the 3rd parameter to sqlite3_open_v2() is not one of the 2725** combinations shown above optionally combined with other 2726** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2727** then the behavior is undefined. 2728** 2729** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2730** opens in the multi-thread [threading mode] as long as the single-thread 2731** mode has not been set at compile-time or start-time. ^If the 2732** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2733** in the serialized [threading mode] unless single-thread was 2734** previously selected at compile-time or start-time. 2735** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2736** eligible to use [shared cache mode], regardless of whether or not shared 2737** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2738** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2739** participate in [shared cache mode] even if it is enabled. 2740** 2741** ^The fourth parameter to sqlite3_open_v2() is the name of the 2742** [sqlite3_vfs] object that defines the operating system interface that 2743** the new database connection should use. ^If the fourth parameter is 2744** a NULL pointer then the default [sqlite3_vfs] object is used. 2745** 2746** ^If the filename is ":memory:", then a private, temporary in-memory database 2747** is created for the connection. ^This in-memory database will vanish when 2748** the database connection is closed. Future versions of SQLite might 2749** make use of additional special filenames that begin with the ":" character. 2750** It is recommended that when a database filename actually does begin with 2751** a ":" character you should prefix the filename with a pathname such as 2752** "./" to avoid ambiguity. 2753** 2754** ^If the filename is an empty string, then a private, temporary 2755** on-disk database will be created. ^This private database will be 2756** automatically deleted as soon as the database connection is closed. 2757** 2758** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2759** 2760** ^If [URI filename] interpretation is enabled, and the filename argument 2761** begins with "file:", then the filename is interpreted as a URI. ^URI 2762** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2763** set in the fourth argument to sqlite3_open_v2(), or if it has 2764** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2765** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2766** As of SQLite version 3.7.7, URI filename interpretation is turned off 2767** by default, but future releases of SQLite might enable URI filename 2768** interpretation by default. See "[URI filenames]" for additional 2769** information. 2770** 2771** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2772** authority, then it must be either an empty string or the string 2773** "localhost". ^If the authority is not an empty string or "localhost", an 2774** error is returned to the caller. ^The fragment component of a URI, if 2775** present, is ignored. 2776** 2777** ^SQLite uses the path component of the URI as the name of the disk file 2778** which contains the database. ^If the path begins with a '/' character, 2779** then it is interpreted as an absolute path. ^If the path does not begin 2780** with a '/' (meaning that the authority section is omitted from the URI) 2781** then the path is interpreted as a relative path. 2782** ^(On windows, the first component of an absolute path 2783** is a drive specification (e.g. "C:").)^ 2784** 2785** [[core URI query parameters]] 2786** The query component of a URI may contain parameters that are interpreted 2787** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2788** SQLite and its built-in [VFSes] interpret the 2789** following query parameters: 2790** 2791** <ul> 2792** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2793** a VFS object that provides the operating system interface that should 2794** be used to access the database file on disk. ^If this option is set to 2795** an empty string the default VFS object is used. ^Specifying an unknown 2796** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2797** present, then the VFS specified by the option takes precedence over 2798** the value passed as the fourth parameter to sqlite3_open_v2(). 2799** 2800** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 2801** "rwc", or "memory". Attempting to set it to any other value is 2802** an error)^. 2803** ^If "ro" is specified, then the database is opened for read-only 2804** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2805** third argument to sqlite3_open_v2(). ^If the mode option is set to 2806** "rw", then the database is opened for read-write (but not create) 2807** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2808** been set. ^Value "rwc" is equivalent to setting both 2809** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 2810** set to "memory" then a pure [in-memory database] that never reads 2811** or writes from disk is used. ^It is an error to specify a value for 2812** the mode parameter that is less restrictive than that specified by 2813** the flags passed in the third parameter to sqlite3_open_v2(). 2814** 2815** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2816** "private". ^Setting it to "shared" is equivalent to setting the 2817** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2818** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2819** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2820** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2821** a URI filename, its value overrides any behavior requested by setting 2822** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2823** 2824** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 2825** [powersafe overwrite] property does or does not apply to the 2826** storage media on which the database file resides. 2827** 2828** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 2829** which if set disables file locking in rollback journal modes. This 2830** is useful for accessing a database on a filesystem that does not 2831** support locking. Caution: Database corruption might result if two 2832** or more processes write to the same database and any one of those 2833** processes uses nolock=1. 2834** 2835** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 2836** parameter that indicates that the database file is stored on 2837** read-only media. ^When immutable is set, SQLite assumes that the 2838** database file cannot be changed, even by a process with higher 2839** privilege, and so the database is opened read-only and all locking 2840** and change detection is disabled. Caution: Setting the immutable 2841** property on a database file that does in fact change can result 2842** in incorrect query results and/or [SQLITE_CORRUPT] errors. 2843** See also: [SQLITE_IOCAP_IMMUTABLE]. 2844** 2845** </ul> 2846** 2847** ^Specifying an unknown parameter in the query component of a URI is not an 2848** error. Future versions of SQLite might understand additional query 2849** parameters. See "[query parameters with special meaning to SQLite]" for 2850** additional information. 2851** 2852** [[URI filename examples]] <h3>URI filename examples</h3> 2853** 2854** <table border="1" align=center cellpadding=5> 2855** <tr><th> URI filenames <th> Results 2856** <tr><td> file:data.db <td> 2857** Open the file "data.db" in the current directory. 2858** <tr><td> file:/home/fred/data.db<br> 2859** file:///home/fred/data.db <br> 2860** file://localhost/home/fred/data.db <br> <td> 2861** Open the database file "/home/fred/data.db". 2862** <tr><td> file://darkstar/home/fred/data.db <td> 2863** An error. "darkstar" is not a recognized authority. 2864** <tr><td style="white-space:nowrap"> 2865** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2866** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2867** C:. Note that the %20 escaping in this example is not strictly 2868** necessary - space characters can be used literally 2869** in URI filenames. 2870** <tr><td> file:data.db?mode=ro&cache=private <td> 2871** Open file "data.db" in the current directory for read-only access. 2872** Regardless of whether or not shared-cache mode is enabled by 2873** default, use a private cache. 2874** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 2875** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 2876** that uses dot-files in place of posix advisory locking. 2877** <tr><td> file:data.db?mode=readonly <td> 2878** An error. "readonly" is not a valid option for the "mode" parameter. 2879** </table> 2880** 2881** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2882** query components of a URI. A hexadecimal escape sequence consists of a 2883** percent sign - "%" - followed by exactly two hexadecimal digits 2884** specifying an octet value. ^Before the path or query components of a 2885** URI filename are interpreted, they are encoded using UTF-8 and all 2886** hexadecimal escape sequences replaced by a single byte containing the 2887** corresponding octet. If this process generates an invalid UTF-8 encoding, 2888** the results are undefined. 2889** 2890** <b>Note to Windows users:</b> The encoding used for the filename argument 2891** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2892** codepage is currently defined. Filenames containing international 2893** characters must be converted to UTF-8 prior to passing them into 2894** sqlite3_open() or sqlite3_open_v2(). 2895** 2896** <b>Note to Windows Runtime users:</b> The temporary directory must be set 2897** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 2898** features that require the use of temporary files may fail. 2899** 2900** See also: [sqlite3_temp_directory] 2901*/ 2902int sqlite3_open( 2903 const char *filename, /* Database filename (UTF-8) */ 2904 sqlite3 **ppDb /* OUT: SQLite db handle */ 2905); 2906int sqlite3_open16( 2907 const void *filename, /* Database filename (UTF-16) */ 2908 sqlite3 **ppDb /* OUT: SQLite db handle */ 2909); 2910int sqlite3_open_v2( 2911 const char *filename, /* Database filename (UTF-8) */ 2912 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2913 int flags, /* Flags */ 2914 const char *zVfs /* Name of VFS module to use */ 2915); 2916 2917/* 2918** CAPI3REF: Obtain Values For URI Parameters 2919** 2920** These are utility routines, useful to VFS implementations, that check 2921** to see if a database file was a URI that contained a specific query 2922** parameter, and if so obtains the value of that query parameter. 2923** 2924** If F is the database filename pointer passed into the xOpen() method of 2925** a VFS implementation when the flags parameter to xOpen() has one or 2926** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 2927** P is the name of the query parameter, then 2928** sqlite3_uri_parameter(F,P) returns the value of the P 2929** parameter if it exists or a NULL pointer if P does not appear as a 2930** query parameter on F. If P is a query parameter of F 2931** has no explicit value, then sqlite3_uri_parameter(F,P) returns 2932** a pointer to an empty string. 2933** 2934** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 2935** parameter and returns true (1) or false (0) according to the value 2936** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 2937** value of query parameter P is one of "yes", "true", or "on" in any 2938** case or if the value begins with a non-zero number. The 2939** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 2940** query parameter P is one of "no", "false", or "off" in any case or 2941** if the value begins with a numeric zero. If P is not a query 2942** parameter on F or if the value of P is does not match any of the 2943** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 2944** 2945** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 2946** 64-bit signed integer and returns that integer, or D if P does not 2947** exist. If the value of P is something other than an integer, then 2948** zero is returned. 2949** 2950** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 2951** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 2952** is not a database file pathname pointer that SQLite passed into the xOpen 2953** VFS method, then the behavior of this routine is undefined and probably 2954** undesirable. 2955*/ 2956const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 2957int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 2958sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 2959 2960 2961/* 2962** CAPI3REF: Error Codes And Messages 2963** 2964** ^The sqlite3_errcode() interface returns the numeric [result code] or 2965** [extended result code] for the most recent failed sqlite3_* API call 2966** associated with a [database connection]. If a prior API call failed 2967** but the most recent API call succeeded, the return value from 2968** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2969** interface is the same except that it always returns the 2970** [extended result code] even when extended result codes are 2971** disabled. 2972** 2973** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2974** text that describes the error, as either UTF-8 or UTF-16 respectively. 2975** ^(Memory to hold the error message string is managed internally. 2976** The application does not need to worry about freeing the result. 2977** However, the error string might be overwritten or deallocated by 2978** subsequent calls to other SQLite interface functions.)^ 2979** 2980** ^The sqlite3_errstr() interface returns the English-language text 2981** that describes the [result code], as UTF-8. 2982** ^(Memory to hold the error message string is managed internally 2983** and must not be freed by the application)^. 2984** 2985** When the serialized [threading mode] is in use, it might be the 2986** case that a second error occurs on a separate thread in between 2987** the time of the first error and the call to these interfaces. 2988** When that happens, the second error will be reported since these 2989** interfaces always report the most recent result. To avoid 2990** this, each thread can obtain exclusive use of the [database connection] D 2991** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2992** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2993** all calls to the interfaces listed here are completed. 2994** 2995** If an interface fails with SQLITE_MISUSE, that means the interface 2996** was invoked incorrectly by the application. In that case, the 2997** error code and message may or may not be set. 2998*/ 2999int sqlite3_errcode(sqlite3 *db); 3000int sqlite3_extended_errcode(sqlite3 *db); 3001const char *sqlite3_errmsg(sqlite3*); 3002const void *sqlite3_errmsg16(sqlite3*); 3003const char *sqlite3_errstr(int); 3004 3005/* 3006** CAPI3REF: SQL Statement Object 3007** KEYWORDS: {prepared statement} {prepared statements} 3008** 3009** An instance of this object represents a single SQL statement. 3010** This object is variously known as a "prepared statement" or a 3011** "compiled SQL statement" or simply as a "statement". 3012** 3013** The life of a statement object goes something like this: 3014** 3015** <ol> 3016** <li> Create the object using [sqlite3_prepare_v2()] or a related 3017** function. 3018** <li> Bind values to [host parameters] using the sqlite3_bind_*() 3019** interfaces. 3020** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3021** <li> Reset the statement using [sqlite3_reset()] then go back 3022** to step 2. Do this zero or more times. 3023** <li> Destroy the object using [sqlite3_finalize()]. 3024** </ol> 3025** 3026** Refer to documentation on individual methods above for additional 3027** information. 3028*/ 3029typedef struct sqlite3_stmt sqlite3_stmt; 3030 3031/* 3032** CAPI3REF: Run-time Limits 3033** 3034** ^(This interface allows the size of various constructs to be limited 3035** on a connection by connection basis. The first parameter is the 3036** [database connection] whose limit is to be set or queried. The 3037** second parameter is one of the [limit categories] that define a 3038** class of constructs to be size limited. The third parameter is the 3039** new limit for that construct.)^ 3040** 3041** ^If the new limit is a negative number, the limit is unchanged. 3042** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3043** [limits | hard upper bound] 3044** set at compile-time by a C preprocessor macro called 3045** [limits | SQLITE_MAX_<i>NAME</i>]. 3046** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3047** ^Attempts to increase a limit above its hard upper bound are 3048** silently truncated to the hard upper bound. 3049** 3050** ^Regardless of whether or not the limit was changed, the 3051** [sqlite3_limit()] interface returns the prior value of the limit. 3052** ^Hence, to find the current value of a limit without changing it, 3053** simply invoke this interface with the third parameter set to -1. 3054** 3055** Run-time limits are intended for use in applications that manage 3056** both their own internal database and also databases that are controlled 3057** by untrusted external sources. An example application might be a 3058** web browser that has its own databases for storing history and 3059** separate databases controlled by JavaScript applications downloaded 3060** off the Internet. The internal databases can be given the 3061** large, default limits. Databases managed by external sources can 3062** be given much smaller limits designed to prevent a denial of service 3063** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3064** interface to further control untrusted SQL. The size of the database 3065** created by an untrusted script can be contained using the 3066** [max_page_count] [PRAGMA]. 3067** 3068** New run-time limit categories may be added in future releases. 3069*/ 3070int sqlite3_limit(sqlite3*, int id, int newVal); 3071 3072/* 3073** CAPI3REF: Run-Time Limit Categories 3074** KEYWORDS: {limit category} {*limit categories} 3075** 3076** These constants define various performance limits 3077** that can be lowered at run-time using [sqlite3_limit()]. 3078** The synopsis of the meanings of the various limits is shown below. 3079** Additional information is available at [limits | Limits in SQLite]. 3080** 3081** <dl> 3082** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3083** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3084** 3085** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3086** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3087** 3088** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3089** <dd>The maximum number of columns in a table definition or in the 3090** result set of a [SELECT] or the maximum number of columns in an index 3091** or in an ORDER BY or GROUP BY clause.</dd>)^ 3092** 3093** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3094** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3095** 3096** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3097** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3098** 3099** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3100** <dd>The maximum number of instructions in a virtual machine program 3101** used to implement an SQL statement. This limit is not currently 3102** enforced, though that might be added in some future release of 3103** SQLite.</dd>)^ 3104** 3105** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3106** <dd>The maximum number of arguments on a function.</dd>)^ 3107** 3108** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3109** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3110** 3111** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3112** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3113** <dd>The maximum length of the pattern argument to the [LIKE] or 3114** [GLOB] operators.</dd>)^ 3115** 3116** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3117** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3118** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3119** 3120** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3121** <dd>The maximum depth of recursion for triggers.</dd>)^ 3122** 3123** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3124** <dd>The maximum number of auxiliary worker threads that a single 3125** [prepared statement] may start.</dd>)^ 3126** </dl> 3127*/ 3128#define SQLITE_LIMIT_LENGTH 0 3129#define SQLITE_LIMIT_SQL_LENGTH 1 3130#define SQLITE_LIMIT_COLUMN 2 3131#define SQLITE_LIMIT_EXPR_DEPTH 3 3132#define SQLITE_LIMIT_COMPOUND_SELECT 4 3133#define SQLITE_LIMIT_VDBE_OP 5 3134#define SQLITE_LIMIT_FUNCTION_ARG 6 3135#define SQLITE_LIMIT_ATTACHED 7 3136#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3137#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3138#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3139#define SQLITE_LIMIT_WORKER_THREADS 11 3140 3141/* 3142** CAPI3REF: Compiling An SQL Statement 3143** KEYWORDS: {SQL statement compiler} 3144** 3145** To execute an SQL query, it must first be compiled into a byte-code 3146** program using one of these routines. 3147** 3148** The first argument, "db", is a [database connection] obtained from a 3149** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3150** [sqlite3_open16()]. The database connection must not have been closed. 3151** 3152** The second argument, "zSql", is the statement to be compiled, encoded 3153** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 3154** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 3155** use UTF-16. 3156** 3157** ^If the nByte argument is less than zero, then zSql is read up to the 3158** first zero terminator. ^If nByte is non-negative, then it is the maximum 3159** number of bytes read from zSql. ^When nByte is non-negative, the 3160** zSql string ends at either the first '\000' or '\u0000' character or 3161** the nByte-th byte, whichever comes first. If the caller knows 3162** that the supplied string is nul-terminated, then there is a small 3163** performance advantage to be gained by passing an nByte parameter that 3164** is equal to the number of bytes in the input string <i>including</i> 3165** the nul-terminator bytes as this saves SQLite from having to 3166** make a copy of the input string. 3167** 3168** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3169** past the end of the first SQL statement in zSql. These routines only 3170** compile the first statement in zSql, so *pzTail is left pointing to 3171** what remains uncompiled. 3172** 3173** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3174** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3175** to NULL. ^If the input text contains no SQL (if the input is an empty 3176** string or a comment) then *ppStmt is set to NULL. 3177** The calling procedure is responsible for deleting the compiled 3178** SQL statement using [sqlite3_finalize()] after it has finished with it. 3179** ppStmt may not be NULL. 3180** 3181** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3182** otherwise an [error code] is returned. 3183** 3184** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 3185** recommended for all new programs. The two older interfaces are retained 3186** for backwards compatibility, but their use is discouraged. 3187** ^In the "v2" interfaces, the prepared statement 3188** that is returned (the [sqlite3_stmt] object) contains a copy of the 3189** original SQL text. This causes the [sqlite3_step()] interface to 3190** behave differently in three ways: 3191** 3192** <ol> 3193** <li> 3194** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3195** always used to do, [sqlite3_step()] will automatically recompile the SQL 3196** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3197** retries will occur before sqlite3_step() gives up and returns an error. 3198** </li> 3199** 3200** <li> 3201** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3202** [error codes] or [extended error codes]. ^The legacy behavior was that 3203** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3204** and the application would have to make a second call to [sqlite3_reset()] 3205** in order to find the underlying cause of the problem. With the "v2" prepare 3206** interfaces, the underlying reason for the error is returned immediately. 3207** </li> 3208** 3209** <li> 3210** ^If the specific value bound to [parameter | host parameter] in the 3211** WHERE clause might influence the choice of query plan for a statement, 3212** then the statement will be automatically recompiled, as if there had been 3213** a schema change, on the first [sqlite3_step()] call following any change 3214** to the [sqlite3_bind_text | bindings] of that [parameter]. 3215** ^The specific value of WHERE-clause [parameter] might influence the 3216** choice of query plan if the parameter is the left-hand side of a [LIKE] 3217** or [GLOB] operator or if the parameter is compared to an indexed column 3218** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3219** </li> 3220** </ol> 3221*/ 3222int sqlite3_prepare( 3223 sqlite3 *db, /* Database handle */ 3224 const char *zSql, /* SQL statement, UTF-8 encoded */ 3225 int nByte, /* Maximum length of zSql in bytes. */ 3226 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3227 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3228); 3229int sqlite3_prepare_v2( 3230 sqlite3 *db, /* Database handle */ 3231 const char *zSql, /* SQL statement, UTF-8 encoded */ 3232 int nByte, /* Maximum length of zSql in bytes. */ 3233 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3234 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3235); 3236int sqlite3_prepare16( 3237 sqlite3 *db, /* Database handle */ 3238 const void *zSql, /* SQL statement, UTF-16 encoded */ 3239 int nByte, /* Maximum length of zSql in bytes. */ 3240 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3241 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3242); 3243int sqlite3_prepare16_v2( 3244 sqlite3 *db, /* Database handle */ 3245 const void *zSql, /* SQL statement, UTF-16 encoded */ 3246 int nByte, /* Maximum length of zSql in bytes. */ 3247 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3248 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3249); 3250 3251/* 3252** CAPI3REF: Retrieving Statement SQL 3253** 3254** ^This interface can be used to retrieve a saved copy of the original 3255** SQL text used to create a [prepared statement] if that statement was 3256** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 3257*/ 3258const char *sqlite3_sql(sqlite3_stmt *pStmt); 3259 3260/* 3261** CAPI3REF: Determine If An SQL Statement Writes The Database 3262** 3263** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3264** and only if the [prepared statement] X makes no direct changes to 3265** the content of the database file. 3266** 3267** Note that [application-defined SQL functions] or 3268** [virtual tables] might change the database indirectly as a side effect. 3269** ^(For example, if an application defines a function "eval()" that 3270** calls [sqlite3_exec()], then the following SQL statement would 3271** change the database file through side-effects: 3272** 3273** <blockquote><pre> 3274** SELECT eval('DELETE FROM t1') FROM t2; 3275** </pre></blockquote> 3276** 3277** But because the [SELECT] statement does not change the database file 3278** directly, sqlite3_stmt_readonly() would still return true.)^ 3279** 3280** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3281** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3282** since the statements themselves do not actually modify the database but 3283** rather they control the timing of when other statements modify the 3284** database. ^The [ATTACH] and [DETACH] statements also cause 3285** sqlite3_stmt_readonly() to return true since, while those statements 3286** change the configuration of a database connection, they do not make 3287** changes to the content of the database files on disk. 3288*/ 3289int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3290 3291/* 3292** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3293** 3294** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3295** [prepared statement] S has been stepped at least once using 3296** [sqlite3_step(S)] but has not run to completion and/or has not 3297** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3298** interface returns false if S is a NULL pointer. If S is not a 3299** NULL pointer and is not a pointer to a valid [prepared statement] 3300** object, then the behavior is undefined and probably undesirable. 3301** 3302** This interface can be used in combination [sqlite3_next_stmt()] 3303** to locate all prepared statements associated with a database 3304** connection that are in need of being reset. This can be used, 3305** for example, in diagnostic routines to search for prepared 3306** statements that are holding a transaction open. 3307*/ 3308int sqlite3_stmt_busy(sqlite3_stmt*); 3309 3310/* 3311** CAPI3REF: Dynamically Typed Value Object 3312** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3313** 3314** SQLite uses the sqlite3_value object to represent all values 3315** that can be stored in a database table. SQLite uses dynamic typing 3316** for the values it stores. ^Values stored in sqlite3_value objects 3317** can be integers, floating point values, strings, BLOBs, or NULL. 3318** 3319** An sqlite3_value object may be either "protected" or "unprotected". 3320** Some interfaces require a protected sqlite3_value. Other interfaces 3321** will accept either a protected or an unprotected sqlite3_value. 3322** Every interface that accepts sqlite3_value arguments specifies 3323** whether or not it requires a protected sqlite3_value. 3324** 3325** The terms "protected" and "unprotected" refer to whether or not 3326** a mutex is held. An internal mutex is held for a protected 3327** sqlite3_value object but no mutex is held for an unprotected 3328** sqlite3_value object. If SQLite is compiled to be single-threaded 3329** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3330** or if SQLite is run in one of reduced mutex modes 3331** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3332** then there is no distinction between protected and unprotected 3333** sqlite3_value objects and they can be used interchangeably. However, 3334** for maximum code portability it is recommended that applications 3335** still make the distinction between protected and unprotected 3336** sqlite3_value objects even when not strictly required. 3337** 3338** ^The sqlite3_value objects that are passed as parameters into the 3339** implementation of [application-defined SQL functions] are protected. 3340** ^The sqlite3_value object returned by 3341** [sqlite3_column_value()] is unprotected. 3342** Unprotected sqlite3_value objects may only be used with 3343** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3344** The [sqlite3_value_blob | sqlite3_value_type()] family of 3345** interfaces require protected sqlite3_value objects. 3346*/ 3347typedef struct Mem sqlite3_value; 3348 3349/* 3350** CAPI3REF: SQL Function Context Object 3351** 3352** The context in which an SQL function executes is stored in an 3353** sqlite3_context object. ^A pointer to an sqlite3_context object 3354** is always first parameter to [application-defined SQL functions]. 3355** The application-defined SQL function implementation will pass this 3356** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3357** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3358** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3359** and/or [sqlite3_set_auxdata()]. 3360*/ 3361typedef struct sqlite3_context sqlite3_context; 3362 3363/* 3364** CAPI3REF: Binding Values To Prepared Statements 3365** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3366** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3367** 3368** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3369** literals may be replaced by a [parameter] that matches one of following 3370** templates: 3371** 3372** <ul> 3373** <li> ? 3374** <li> ?NNN 3375** <li> :VVV 3376** <li> @VVV 3377** <li> $VVV 3378** </ul> 3379** 3380** In the templates above, NNN represents an integer literal, 3381** and VVV represents an alphanumeric identifier.)^ ^The values of these 3382** parameters (also called "host parameter names" or "SQL parameters") 3383** can be set using the sqlite3_bind_*() routines defined here. 3384** 3385** ^The first argument to the sqlite3_bind_*() routines is always 3386** a pointer to the [sqlite3_stmt] object returned from 3387** [sqlite3_prepare_v2()] or its variants. 3388** 3389** ^The second argument is the index of the SQL parameter to be set. 3390** ^The leftmost SQL parameter has an index of 1. ^When the same named 3391** SQL parameter is used more than once, second and subsequent 3392** occurrences have the same index as the first occurrence. 3393** ^The index for named parameters can be looked up using the 3394** [sqlite3_bind_parameter_index()] API if desired. ^The index 3395** for "?NNN" parameters is the value of NNN. 3396** ^The NNN value must be between 1 and the [sqlite3_limit()] 3397** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3398** 3399** ^The third argument is the value to bind to the parameter. 3400** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3401** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3402** is ignored and the end result is the same as sqlite3_bind_null(). 3403** 3404** ^(In those routines that have a fourth argument, its value is the 3405** number of bytes in the parameter. To be clear: the value is the 3406** number of <u>bytes</u> in the value, not the number of characters.)^ 3407** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3408** is negative, then the length of the string is 3409** the number of bytes up to the first zero terminator. 3410** If the fourth parameter to sqlite3_bind_blob() is negative, then 3411** the behavior is undefined. 3412** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3413** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3414** that parameter must be the byte offset 3415** where the NUL terminator would occur assuming the string were NUL 3416** terminated. If any NUL characters occur at byte offsets less than 3417** the value of the fourth parameter then the resulting string value will 3418** contain embedded NULs. The result of expressions involving strings 3419** with embedded NULs is undefined. 3420** 3421** ^The fifth argument to the BLOB and string binding interfaces 3422** is a destructor used to dispose of the BLOB or 3423** string after SQLite has finished with it. ^The destructor is called 3424** to dispose of the BLOB or string even if the call to bind API fails. 3425** ^If the fifth argument is 3426** the special value [SQLITE_STATIC], then SQLite assumes that the 3427** information is in static, unmanaged space and does not need to be freed. 3428** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3429** SQLite makes its own private copy of the data immediately, before 3430** the sqlite3_bind_*() routine returns. 3431** 3432** ^The sixth argument to sqlite3_bind_text64() must be one of 3433** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3434** to specify the encoding of the text in the third parameter. If 3435** the sixth argument to sqlite3_bind_text64() is not one of the 3436** allowed values shown above, or if the text encoding is different 3437** from the encoding specified by the sixth parameter, then the behavior 3438** is undefined. 3439** 3440** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3441** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3442** (just an integer to hold its size) while it is being processed. 3443** Zeroblobs are intended to serve as placeholders for BLOBs whose 3444** content is later written using 3445** [sqlite3_blob_open | incremental BLOB I/O] routines. 3446** ^A negative value for the zeroblob results in a zero-length BLOB. 3447** 3448** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3449** for the [prepared statement] or with a prepared statement for which 3450** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3451** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3452** routine is passed a [prepared statement] that has been finalized, the 3453** result is undefined and probably harmful. 3454** 3455** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3456** ^Unbound parameters are interpreted as NULL. 3457** 3458** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3459** [error code] if anything goes wrong. 3460** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3461** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3462** [SQLITE_MAX_LENGTH]. 3463** ^[SQLITE_RANGE] is returned if the parameter 3464** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3465** 3466** See also: [sqlite3_bind_parameter_count()], 3467** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3468*/ 3469int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3470int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3471 void(*)(void*)); 3472int sqlite3_bind_double(sqlite3_stmt*, int, double); 3473int sqlite3_bind_int(sqlite3_stmt*, int, int); 3474int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3475int sqlite3_bind_null(sqlite3_stmt*, int); 3476int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3477int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3478int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3479 void(*)(void*), unsigned char encoding); 3480int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3481int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3482 3483/* 3484** CAPI3REF: Number Of SQL Parameters 3485** 3486** ^This routine can be used to find the number of [SQL parameters] 3487** in a [prepared statement]. SQL parameters are tokens of the 3488** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3489** placeholders for values that are [sqlite3_bind_blob | bound] 3490** to the parameters at a later time. 3491** 3492** ^(This routine actually returns the index of the largest (rightmost) 3493** parameter. For all forms except ?NNN, this will correspond to the 3494** number of unique parameters. If parameters of the ?NNN form are used, 3495** there may be gaps in the list.)^ 3496** 3497** See also: [sqlite3_bind_blob|sqlite3_bind()], 3498** [sqlite3_bind_parameter_name()], and 3499** [sqlite3_bind_parameter_index()]. 3500*/ 3501int sqlite3_bind_parameter_count(sqlite3_stmt*); 3502 3503/* 3504** CAPI3REF: Name Of A Host Parameter 3505** 3506** ^The sqlite3_bind_parameter_name(P,N) interface returns 3507** the name of the N-th [SQL parameter] in the [prepared statement] P. 3508** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3509** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3510** respectively. 3511** In other words, the initial ":" or "$" or "@" or "?" 3512** is included as part of the name.)^ 3513** ^Parameters of the form "?" without a following integer have no name 3514** and are referred to as "nameless" or "anonymous parameters". 3515** 3516** ^The first host parameter has an index of 1, not 0. 3517** 3518** ^If the value N is out of range or if the N-th parameter is 3519** nameless, then NULL is returned. ^The returned string is 3520** always in UTF-8 encoding even if the named parameter was 3521** originally specified as UTF-16 in [sqlite3_prepare16()] or 3522** [sqlite3_prepare16_v2()]. 3523** 3524** See also: [sqlite3_bind_blob|sqlite3_bind()], 3525** [sqlite3_bind_parameter_count()], and 3526** [sqlite3_bind_parameter_index()]. 3527*/ 3528const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3529 3530/* 3531** CAPI3REF: Index Of A Parameter With A Given Name 3532** 3533** ^Return the index of an SQL parameter given its name. ^The 3534** index value returned is suitable for use as the second 3535** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3536** is returned if no matching parameter is found. ^The parameter 3537** name must be given in UTF-8 even if the original statement 3538** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3539** 3540** See also: [sqlite3_bind_blob|sqlite3_bind()], 3541** [sqlite3_bind_parameter_count()], and 3542** [sqlite3_bind_parameter_index()]. 3543*/ 3544int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3545 3546/* 3547** CAPI3REF: Reset All Bindings On A Prepared Statement 3548** 3549** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3550** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3551** ^Use this routine to reset all host parameters to NULL. 3552*/ 3553int sqlite3_clear_bindings(sqlite3_stmt*); 3554 3555/* 3556** CAPI3REF: Number Of Columns In A Result Set 3557** 3558** ^Return the number of columns in the result set returned by the 3559** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3560** statement that does not return data (for example an [UPDATE]). 3561** 3562** See also: [sqlite3_data_count()] 3563*/ 3564int sqlite3_column_count(sqlite3_stmt *pStmt); 3565 3566/* 3567** CAPI3REF: Column Names In A Result Set 3568** 3569** ^These routines return the name assigned to a particular column 3570** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3571** interface returns a pointer to a zero-terminated UTF-8 string 3572** and sqlite3_column_name16() returns a pointer to a zero-terminated 3573** UTF-16 string. ^The first parameter is the [prepared statement] 3574** that implements the [SELECT] statement. ^The second parameter is the 3575** column number. ^The leftmost column is number 0. 3576** 3577** ^The returned string pointer is valid until either the [prepared statement] 3578** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3579** reprepared by the first call to [sqlite3_step()] for a particular run 3580** or until the next call to 3581** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3582** 3583** ^If sqlite3_malloc() fails during the processing of either routine 3584** (for example during a conversion from UTF-8 to UTF-16) then a 3585** NULL pointer is returned. 3586** 3587** ^The name of a result column is the value of the "AS" clause for 3588** that column, if there is an AS clause. If there is no AS clause 3589** then the name of the column is unspecified and may change from 3590** one release of SQLite to the next. 3591*/ 3592const char *sqlite3_column_name(sqlite3_stmt*, int N); 3593const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3594 3595/* 3596** CAPI3REF: Source Of Data In A Query Result 3597** 3598** ^These routines provide a means to determine the database, table, and 3599** table column that is the origin of a particular result column in 3600** [SELECT] statement. 3601** ^The name of the database or table or column can be returned as 3602** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3603** the database name, the _table_ routines return the table name, and 3604** the origin_ routines return the column name. 3605** ^The returned string is valid until the [prepared statement] is destroyed 3606** using [sqlite3_finalize()] or until the statement is automatically 3607** reprepared by the first call to [sqlite3_step()] for a particular run 3608** or until the same information is requested 3609** again in a different encoding. 3610** 3611** ^The names returned are the original un-aliased names of the 3612** database, table, and column. 3613** 3614** ^The first argument to these interfaces is a [prepared statement]. 3615** ^These functions return information about the Nth result column returned by 3616** the statement, where N is the second function argument. 3617** ^The left-most column is column 0 for these routines. 3618** 3619** ^If the Nth column returned by the statement is an expression or 3620** subquery and is not a column value, then all of these functions return 3621** NULL. ^These routine might also return NULL if a memory allocation error 3622** occurs. ^Otherwise, they return the name of the attached database, table, 3623** or column that query result column was extracted from. 3624** 3625** ^As with all other SQLite APIs, those whose names end with "16" return 3626** UTF-16 encoded strings and the other functions return UTF-8. 3627** 3628** ^These APIs are only available if the library was compiled with the 3629** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3630** 3631** If two or more threads call one or more of these routines against the same 3632** prepared statement and column at the same time then the results are 3633** undefined. 3634** 3635** If two or more threads call one or more 3636** [sqlite3_column_database_name | column metadata interfaces] 3637** for the same [prepared statement] and result column 3638** at the same time then the results are undefined. 3639*/ 3640const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3641const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3642const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3643const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3644const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3645const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3646 3647/* 3648** CAPI3REF: Declared Datatype Of A Query Result 3649** 3650** ^(The first parameter is a [prepared statement]. 3651** If this statement is a [SELECT] statement and the Nth column of the 3652** returned result set of that [SELECT] is a table column (not an 3653** expression or subquery) then the declared type of the table 3654** column is returned.)^ ^If the Nth column of the result set is an 3655** expression or subquery, then a NULL pointer is returned. 3656** ^The returned string is always UTF-8 encoded. 3657** 3658** ^(For example, given the database schema: 3659** 3660** CREATE TABLE t1(c1 VARIANT); 3661** 3662** and the following statement to be compiled: 3663** 3664** SELECT c1 + 1, c1 FROM t1; 3665** 3666** this routine would return the string "VARIANT" for the second result 3667** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3668** 3669** ^SQLite uses dynamic run-time typing. ^So just because a column 3670** is declared to contain a particular type does not mean that the 3671** data stored in that column is of the declared type. SQLite is 3672** strongly typed, but the typing is dynamic not static. ^Type 3673** is associated with individual values, not with the containers 3674** used to hold those values. 3675*/ 3676const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3677const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3678 3679/* 3680** CAPI3REF: Evaluate An SQL Statement 3681** 3682** After a [prepared statement] has been prepared using either 3683** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3684** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3685** must be called one or more times to evaluate the statement. 3686** 3687** The details of the behavior of the sqlite3_step() interface depend 3688** on whether the statement was prepared using the newer "v2" interface 3689** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3690** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3691** new "v2" interface is recommended for new applications but the legacy 3692** interface will continue to be supported. 3693** 3694** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3695** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3696** ^With the "v2" interface, any of the other [result codes] or 3697** [extended result codes] might be returned as well. 3698** 3699** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3700** database locks it needs to do its job. ^If the statement is a [COMMIT] 3701** or occurs outside of an explicit transaction, then you can retry the 3702** statement. If the statement is not a [COMMIT] and occurs within an 3703** explicit transaction then you should rollback the transaction before 3704** continuing. 3705** 3706** ^[SQLITE_DONE] means that the statement has finished executing 3707** successfully. sqlite3_step() should not be called again on this virtual 3708** machine without first calling [sqlite3_reset()] to reset the virtual 3709** machine back to its initial state. 3710** 3711** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3712** is returned each time a new row of data is ready for processing by the 3713** caller. The values may be accessed using the [column access functions]. 3714** sqlite3_step() is called again to retrieve the next row of data. 3715** 3716** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3717** violation) has occurred. sqlite3_step() should not be called again on 3718** the VM. More information may be found by calling [sqlite3_errmsg()]. 3719** ^With the legacy interface, a more specific error code (for example, 3720** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3721** can be obtained by calling [sqlite3_reset()] on the 3722** [prepared statement]. ^In the "v2" interface, 3723** the more specific error code is returned directly by sqlite3_step(). 3724** 3725** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3726** Perhaps it was called on a [prepared statement] that has 3727** already been [sqlite3_finalize | finalized] or on one that had 3728** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3729** be the case that the same database connection is being used by two or 3730** more threads at the same moment in time. 3731** 3732** For all versions of SQLite up to and including 3.6.23.1, a call to 3733** [sqlite3_reset()] was required after sqlite3_step() returned anything 3734** other than [SQLITE_ROW] before any subsequent invocation of 3735** sqlite3_step(). Failure to reset the prepared statement using 3736** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3737** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3738** calling [sqlite3_reset()] automatically in this circumstance rather 3739** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3740** break because any application that ever receives an SQLITE_MISUSE error 3741** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3742** can be used to restore the legacy behavior. 3743** 3744** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3745** API always returns a generic error code, [SQLITE_ERROR], following any 3746** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3747** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3748** specific [error codes] that better describes the error. 3749** We admit that this is a goofy design. The problem has been fixed 3750** with the "v2" interface. If you prepare all of your SQL statements 3751** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3752** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3753** then the more specific [error codes] are returned directly 3754** by sqlite3_step(). The use of the "v2" interface is recommended. 3755*/ 3756int sqlite3_step(sqlite3_stmt*); 3757 3758/* 3759** CAPI3REF: Number of columns in a result set 3760** 3761** ^The sqlite3_data_count(P) interface returns the number of columns in the 3762** current row of the result set of [prepared statement] P. 3763** ^If prepared statement P does not have results ready to return 3764** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3765** interfaces) then sqlite3_data_count(P) returns 0. 3766** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3767** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 3768** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 3769** will return non-zero if previous call to [sqlite3_step](P) returned 3770** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 3771** where it always returns zero since each step of that multi-step 3772** pragma returns 0 columns of data. 3773** 3774** See also: [sqlite3_column_count()] 3775*/ 3776int sqlite3_data_count(sqlite3_stmt *pStmt); 3777 3778/* 3779** CAPI3REF: Fundamental Datatypes 3780** KEYWORDS: SQLITE_TEXT 3781** 3782** ^(Every value in SQLite has one of five fundamental datatypes: 3783** 3784** <ul> 3785** <li> 64-bit signed integer 3786** <li> 64-bit IEEE floating point number 3787** <li> string 3788** <li> BLOB 3789** <li> NULL 3790** </ul>)^ 3791** 3792** These constants are codes for each of those types. 3793** 3794** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3795** for a completely different meaning. Software that links against both 3796** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3797** SQLITE_TEXT. 3798*/ 3799#define SQLITE_INTEGER 1 3800#define SQLITE_FLOAT 2 3801#define SQLITE_BLOB 4 3802#define SQLITE_NULL 5 3803#ifdef SQLITE_TEXT 3804# undef SQLITE_TEXT 3805#else 3806# define SQLITE_TEXT 3 3807#endif 3808#define SQLITE3_TEXT 3 3809 3810/* 3811** CAPI3REF: Result Values From A Query 3812** KEYWORDS: {column access functions} 3813** 3814** These routines form the "result set" interface. 3815** 3816** ^These routines return information about a single column of the current 3817** result row of a query. ^In every case the first argument is a pointer 3818** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3819** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3820** and the second argument is the index of the column for which information 3821** should be returned. ^The leftmost column of the result set has the index 0. 3822** ^The number of columns in the result can be determined using 3823** [sqlite3_column_count()]. 3824** 3825** If the SQL statement does not currently point to a valid row, or if the 3826** column index is out of range, the result is undefined. 3827** These routines may only be called when the most recent call to 3828** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3829** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3830** If any of these routines are called after [sqlite3_reset()] or 3831** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3832** something other than [SQLITE_ROW], the results are undefined. 3833** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3834** are called from a different thread while any of these routines 3835** are pending, then the results are undefined. 3836** 3837** ^The sqlite3_column_type() routine returns the 3838** [SQLITE_INTEGER | datatype code] for the initial data type 3839** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3840** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3841** returned by sqlite3_column_type() is only meaningful if no type 3842** conversions have occurred as described below. After a type conversion, 3843** the value returned by sqlite3_column_type() is undefined. Future 3844** versions of SQLite may change the behavior of sqlite3_column_type() 3845** following a type conversion. 3846** 3847** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3848** routine returns the number of bytes in that BLOB or string. 3849** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3850** the string to UTF-8 and then returns the number of bytes. 3851** ^If the result is a numeric value then sqlite3_column_bytes() uses 3852** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3853** the number of bytes in that string. 3854** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3855** 3856** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3857** routine returns the number of bytes in that BLOB or string. 3858** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3859** the string to UTF-16 and then returns the number of bytes. 3860** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3861** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3862** the number of bytes in that string. 3863** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3864** 3865** ^The values returned by [sqlite3_column_bytes()] and 3866** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3867** of the string. ^For clarity: the values returned by 3868** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3869** bytes in the string, not the number of characters. 3870** 3871** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3872** even empty strings, are always zero-terminated. ^The return 3873** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3874** 3875** ^The object returned by [sqlite3_column_value()] is an 3876** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3877** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3878** If the [unprotected sqlite3_value] object returned by 3879** [sqlite3_column_value()] is used in any other way, including calls 3880** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3881** or [sqlite3_value_bytes()], then the behavior is undefined. 3882** 3883** These routines attempt to convert the value where appropriate. ^For 3884** example, if the internal representation is FLOAT and a text result 3885** is requested, [sqlite3_snprintf()] is used internally to perform the 3886** conversion automatically. ^(The following table details the conversions 3887** that are applied: 3888** 3889** <blockquote> 3890** <table border="1"> 3891** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3892** 3893** <tr><td> NULL <td> INTEGER <td> Result is 0 3894** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3895** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 3896** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 3897** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3898** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3899** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3900** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 3901** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3902** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 3903** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 3904** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 3905** <tr><td> TEXT <td> BLOB <td> No change 3906** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 3907** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 3908** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3909** </table> 3910** </blockquote>)^ 3911** 3912** The table above makes reference to standard C library functions atoi() 3913** and atof(). SQLite does not really use these functions. It has its 3914** own equivalent internal routines. The atoi() and atof() names are 3915** used in the table for brevity and because they are familiar to most 3916** C programmers. 3917** 3918** Note that when type conversions occur, pointers returned by prior 3919** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3920** sqlite3_column_text16() may be invalidated. 3921** Type conversions and pointer invalidations might occur 3922** in the following cases: 3923** 3924** <ul> 3925** <li> The initial content is a BLOB and sqlite3_column_text() or 3926** sqlite3_column_text16() is called. A zero-terminator might 3927** need to be added to the string.</li> 3928** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3929** sqlite3_column_text16() is called. The content must be converted 3930** to UTF-16.</li> 3931** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3932** sqlite3_column_text() is called. The content must be converted 3933** to UTF-8.</li> 3934** </ul> 3935** 3936** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3937** not invalidate a prior pointer, though of course the content of the buffer 3938** that the prior pointer references will have been modified. Other kinds 3939** of conversion are done in place when it is possible, but sometimes they 3940** are not possible and in those cases prior pointers are invalidated. 3941** 3942** The safest and easiest to remember policy is to invoke these routines 3943** in one of the following ways: 3944** 3945** <ul> 3946** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3947** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3948** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3949** </ul> 3950** 3951** In other words, you should call sqlite3_column_text(), 3952** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3953** into the desired format, then invoke sqlite3_column_bytes() or 3954** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3955** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3956** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3957** with calls to sqlite3_column_bytes(). 3958** 3959** ^The pointers returned are valid until a type conversion occurs as 3960** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3961** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3962** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3963** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3964** [sqlite3_free()]. 3965** 3966** ^(If a memory allocation error occurs during the evaluation of any 3967** of these routines, a default value is returned. The default value 3968** is either the integer 0, the floating point number 0.0, or a NULL 3969** pointer. Subsequent calls to [sqlite3_errcode()] will return 3970** [SQLITE_NOMEM].)^ 3971*/ 3972const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3973int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3974int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3975double sqlite3_column_double(sqlite3_stmt*, int iCol); 3976int sqlite3_column_int(sqlite3_stmt*, int iCol); 3977sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3978const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3979const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3980int sqlite3_column_type(sqlite3_stmt*, int iCol); 3981sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3982 3983/* 3984** CAPI3REF: Destroy A Prepared Statement Object 3985** 3986** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3987** ^If the most recent evaluation of the statement encountered no errors 3988** or if the statement is never been evaluated, then sqlite3_finalize() returns 3989** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 3990** sqlite3_finalize(S) returns the appropriate [error code] or 3991** [extended error code]. 3992** 3993** ^The sqlite3_finalize(S) routine can be called at any point during 3994** the life cycle of [prepared statement] S: 3995** before statement S is ever evaluated, after 3996** one or more calls to [sqlite3_reset()], or after any call 3997** to [sqlite3_step()] regardless of whether or not the statement has 3998** completed execution. 3999** 4000** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4001** 4002** The application must finalize every [prepared statement] in order to avoid 4003** resource leaks. It is a grievous error for the application to try to use 4004** a prepared statement after it has been finalized. Any use of a prepared 4005** statement after it has been finalized can result in undefined and 4006** undesirable behavior such as segfaults and heap corruption. 4007*/ 4008int sqlite3_finalize(sqlite3_stmt *pStmt); 4009 4010/* 4011** CAPI3REF: Reset A Prepared Statement Object 4012** 4013** The sqlite3_reset() function is called to reset a [prepared statement] 4014** object back to its initial state, ready to be re-executed. 4015** ^Any SQL statement variables that had values bound to them using 4016** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4017** Use [sqlite3_clear_bindings()] to reset the bindings. 4018** 4019** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4020** back to the beginning of its program. 4021** 4022** ^If the most recent call to [sqlite3_step(S)] for the 4023** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4024** or if [sqlite3_step(S)] has never before been called on S, 4025** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4026** 4027** ^If the most recent call to [sqlite3_step(S)] for the 4028** [prepared statement] S indicated an error, then 4029** [sqlite3_reset(S)] returns an appropriate [error code]. 4030** 4031** ^The [sqlite3_reset(S)] interface does not change the values 4032** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4033*/ 4034int sqlite3_reset(sqlite3_stmt *pStmt); 4035 4036/* 4037** CAPI3REF: Create Or Redefine SQL Functions 4038** KEYWORDS: {function creation routines} 4039** KEYWORDS: {application-defined SQL function} 4040** KEYWORDS: {application-defined SQL functions} 4041** 4042** ^These functions (collectively known as "function creation routines") 4043** are used to add SQL functions or aggregates or to redefine the behavior 4044** of existing SQL functions or aggregates. The only differences between 4045** these routines are the text encoding expected for 4046** the second parameter (the name of the function being created) 4047** and the presence or absence of a destructor callback for 4048** the application data pointer. 4049** 4050** ^The first parameter is the [database connection] to which the SQL 4051** function is to be added. ^If an application uses more than one database 4052** connection then application-defined SQL functions must be added 4053** to each database connection separately. 4054** 4055** ^The second parameter is the name of the SQL function to be created or 4056** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4057** representation, exclusive of the zero-terminator. ^Note that the name 4058** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4059** ^Any attempt to create a function with a longer name 4060** will result in [SQLITE_MISUSE] being returned. 4061** 4062** ^The third parameter (nArg) 4063** is the number of arguments that the SQL function or 4064** aggregate takes. ^If this parameter is -1, then the SQL function or 4065** aggregate may take any number of arguments between 0 and the limit 4066** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4067** parameter is less than -1 or greater than 127 then the behavior is 4068** undefined. 4069** 4070** ^The fourth parameter, eTextRep, specifies what 4071** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4072** its parameters. The application should set this parameter to 4073** [SQLITE_UTF16LE] if the function implementation invokes 4074** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4075** implementation invokes [sqlite3_value_text16be()] on an input, or 4076** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4077** otherwise. ^The same SQL function may be registered multiple times using 4078** different preferred text encodings, with different implementations for 4079** each encoding. 4080** ^When multiple implementations of the same function are available, SQLite 4081** will pick the one that involves the least amount of data conversion. 4082** 4083** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4084** to signal that the function will always return the same result given 4085** the same inputs within a single SQL statement. Most SQL functions are 4086** deterministic. The built-in [random()] SQL function is an example of a 4087** function that is not deterministic. The SQLite query planner is able to 4088** perform additional optimizations on deterministic functions, so use 4089** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4090** 4091** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4092** function can gain access to this pointer using [sqlite3_user_data()].)^ 4093** 4094** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4095** pointers to C-language functions that implement the SQL function or 4096** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4097** callback only; NULL pointers must be passed as the xStep and xFinal 4098** parameters. ^An aggregate SQL function requires an implementation of xStep 4099** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4100** SQL function or aggregate, pass NULL pointers for all three function 4101** callbacks. 4102** 4103** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4104** then it is destructor for the application data pointer. 4105** The destructor is invoked when the function is deleted, either by being 4106** overloaded or when the database connection closes.)^ 4107** ^The destructor is also invoked if the call to 4108** sqlite3_create_function_v2() fails. 4109** ^When the destructor callback of the tenth parameter is invoked, it 4110** is passed a single argument which is a copy of the application data 4111** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4112** 4113** ^It is permitted to register multiple implementations of the same 4114** functions with the same name but with either differing numbers of 4115** arguments or differing preferred text encodings. ^SQLite will use 4116** the implementation that most closely matches the way in which the 4117** SQL function is used. ^A function implementation with a non-negative 4118** nArg parameter is a better match than a function implementation with 4119** a negative nArg. ^A function where the preferred text encoding 4120** matches the database encoding is a better 4121** match than a function where the encoding is different. 4122** ^A function where the encoding difference is between UTF16le and UTF16be 4123** is a closer match than a function where the encoding difference is 4124** between UTF8 and UTF16. 4125** 4126** ^Built-in functions may be overloaded by new application-defined functions. 4127** 4128** ^An application-defined function is permitted to call other 4129** SQLite interfaces. However, such calls must not 4130** close the database connection nor finalize or reset the prepared 4131** statement in which the function is running. 4132*/ 4133int sqlite3_create_function( 4134 sqlite3 *db, 4135 const char *zFunctionName, 4136 int nArg, 4137 int eTextRep, 4138 void *pApp, 4139 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4140 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4141 void (*xFinal)(sqlite3_context*) 4142); 4143int sqlite3_create_function16( 4144 sqlite3 *db, 4145 const void *zFunctionName, 4146 int nArg, 4147 int eTextRep, 4148 void *pApp, 4149 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4150 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4151 void (*xFinal)(sqlite3_context*) 4152); 4153int sqlite3_create_function_v2( 4154 sqlite3 *db, 4155 const char *zFunctionName, 4156 int nArg, 4157 int eTextRep, 4158 void *pApp, 4159 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4160 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4161 void (*xFinal)(sqlite3_context*), 4162 void(*xDestroy)(void*) 4163); 4164 4165/* 4166** CAPI3REF: Text Encodings 4167** 4168** These constant define integer codes that represent the various 4169** text encodings supported by SQLite. 4170*/ 4171#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4172#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4173#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4174#define SQLITE_UTF16 4 /* Use native byte order */ 4175#define SQLITE_ANY 5 /* Deprecated */ 4176#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4177 4178/* 4179** CAPI3REF: Function Flags 4180** 4181** These constants may be ORed together with the 4182** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4183** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4184** [sqlite3_create_function_v2()]. 4185*/ 4186#define SQLITE_DETERMINISTIC 0x800 4187 4188/* 4189** CAPI3REF: Deprecated Functions 4190** DEPRECATED 4191** 4192** These functions are [deprecated]. In order to maintain 4193** backwards compatibility with older code, these functions continue 4194** to be supported. However, new applications should avoid 4195** the use of these functions. To help encourage people to avoid 4196** using these functions, we are not going to tell you what they do. 4197*/ 4198#ifndef SQLITE_OMIT_DEPRECATED 4199SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4200SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4201SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4202SQLITE_DEPRECATED int sqlite3_global_recover(void); 4203SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4204SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4205 void*,sqlite3_int64); 4206#endif 4207 4208/* 4209** CAPI3REF: Obtaining SQL Function Parameter Values 4210** 4211** The C-language implementation of SQL functions and aggregates uses 4212** this set of interface routines to access the parameter values on 4213** the function or aggregate. 4214** 4215** The xFunc (for scalar functions) or xStep (for aggregates) parameters 4216** to [sqlite3_create_function()] and [sqlite3_create_function16()] 4217** define callbacks that implement the SQL functions and aggregates. 4218** The 3rd parameter to these callbacks is an array of pointers to 4219** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 4220** each parameter to the SQL function. These routines are used to 4221** extract values from the [sqlite3_value] objects. 4222** 4223** These routines work only with [protected sqlite3_value] objects. 4224** Any attempt to use these routines on an [unprotected sqlite3_value] 4225** object results in undefined behavior. 4226** 4227** ^These routines work just like the corresponding [column access functions] 4228** except that these routines take a single [protected sqlite3_value] object 4229** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4230** 4231** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4232** in the native byte-order of the host machine. ^The 4233** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4234** extract UTF-16 strings as big-endian and little-endian respectively. 4235** 4236** ^(The sqlite3_value_numeric_type() interface attempts to apply 4237** numeric affinity to the value. This means that an attempt is 4238** made to convert the value to an integer or floating point. If 4239** such a conversion is possible without loss of information (in other 4240** words, if the value is a string that looks like a number) 4241** then the conversion is performed. Otherwise no conversion occurs. 4242** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4243** 4244** Please pay particular attention to the fact that the pointer returned 4245** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4246** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4247** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4248** or [sqlite3_value_text16()]. 4249** 4250** These routines must be called from the same thread as 4251** the SQL function that supplied the [sqlite3_value*] parameters. 4252*/ 4253const void *sqlite3_value_blob(sqlite3_value*); 4254int sqlite3_value_bytes(sqlite3_value*); 4255int sqlite3_value_bytes16(sqlite3_value*); 4256double sqlite3_value_double(sqlite3_value*); 4257int sqlite3_value_int(sqlite3_value*); 4258sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4259const unsigned char *sqlite3_value_text(sqlite3_value*); 4260const void *sqlite3_value_text16(sqlite3_value*); 4261const void *sqlite3_value_text16le(sqlite3_value*); 4262const void *sqlite3_value_text16be(sqlite3_value*); 4263int sqlite3_value_type(sqlite3_value*); 4264int sqlite3_value_numeric_type(sqlite3_value*); 4265 4266/* 4267** CAPI3REF: Obtain Aggregate Function Context 4268** 4269** Implementations of aggregate SQL functions use this 4270** routine to allocate memory for storing their state. 4271** 4272** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4273** for a particular aggregate function, SQLite 4274** allocates N of memory, zeroes out that memory, and returns a pointer 4275** to the new memory. ^On second and subsequent calls to 4276** sqlite3_aggregate_context() for the same aggregate function instance, 4277** the same buffer is returned. Sqlite3_aggregate_context() is normally 4278** called once for each invocation of the xStep callback and then one 4279** last time when the xFinal callback is invoked. ^(When no rows match 4280** an aggregate query, the xStep() callback of the aggregate function 4281** implementation is never called and xFinal() is called exactly once. 4282** In those cases, sqlite3_aggregate_context() might be called for the 4283** first time from within xFinal().)^ 4284** 4285** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4286** when first called if N is less than or equal to zero or if a memory 4287** allocate error occurs. 4288** 4289** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4290** determined by the N parameter on first successful call. Changing the 4291** value of N in subsequent call to sqlite3_aggregate_context() within 4292** the same aggregate function instance will not resize the memory 4293** allocation.)^ Within the xFinal callback, it is customary to set 4294** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4295** pointless memory allocations occur. 4296** 4297** ^SQLite automatically frees the memory allocated by 4298** sqlite3_aggregate_context() when the aggregate query concludes. 4299** 4300** The first parameter must be a copy of the 4301** [sqlite3_context | SQL function context] that is the first parameter 4302** to the xStep or xFinal callback routine that implements the aggregate 4303** function. 4304** 4305** This routine must be called from the same thread in which 4306** the aggregate SQL function is running. 4307*/ 4308void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4309 4310/* 4311** CAPI3REF: User Data For Functions 4312** 4313** ^The sqlite3_user_data() interface returns a copy of 4314** the pointer that was the pUserData parameter (the 5th parameter) 4315** of the [sqlite3_create_function()] 4316** and [sqlite3_create_function16()] routines that originally 4317** registered the application defined function. 4318** 4319** This routine must be called from the same thread in which 4320** the application-defined function is running. 4321*/ 4322void *sqlite3_user_data(sqlite3_context*); 4323 4324/* 4325** CAPI3REF: Database Connection For Functions 4326** 4327** ^The sqlite3_context_db_handle() interface returns a copy of 4328** the pointer to the [database connection] (the 1st parameter) 4329** of the [sqlite3_create_function()] 4330** and [sqlite3_create_function16()] routines that originally 4331** registered the application defined function. 4332*/ 4333sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4334 4335/* 4336** CAPI3REF: Function Auxiliary Data 4337** 4338** These functions may be used by (non-aggregate) SQL functions to 4339** associate metadata with argument values. If the same value is passed to 4340** multiple invocations of the same SQL function during query execution, under 4341** some circumstances the associated metadata may be preserved. An example 4342** of where this might be useful is in a regular-expression matching 4343** function. The compiled version of the regular expression can be stored as 4344** metadata associated with the pattern string. 4345** Then as long as the pattern string remains the same, 4346** the compiled regular expression can be reused on multiple 4347** invocations of the same function. 4348** 4349** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4350** associated by the sqlite3_set_auxdata() function with the Nth argument 4351** value to the application-defined function. ^If there is no metadata 4352** associated with the function argument, this sqlite3_get_auxdata() interface 4353** returns a NULL pointer. 4354** 4355** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4356** argument of the application-defined function. ^Subsequent 4357** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4358** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4359** NULL if the metadata has been discarded. 4360** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4361** SQLite will invoke the destructor function X with parameter P exactly 4362** once, when the metadata is discarded. 4363** SQLite is free to discard the metadata at any time, including: <ul> 4364** <li> when the corresponding function parameter changes, or 4365** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4366** SQL statement, or 4367** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or 4368** <li> during the original sqlite3_set_auxdata() call when a memory 4369** allocation error occurs. </ul>)^ 4370** 4371** Note the last bullet in particular. The destructor X in 4372** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 4373** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 4374** should be called near the end of the function implementation and the 4375** function implementation should not make any use of P after 4376** sqlite3_set_auxdata() has been called. 4377** 4378** ^(In practice, metadata is preserved between function calls for 4379** function parameters that are compile-time constants, including literal 4380** values and [parameters] and expressions composed from the same.)^ 4381** 4382** These routines must be called from the same thread in which 4383** the SQL function is running. 4384*/ 4385void *sqlite3_get_auxdata(sqlite3_context*, int N); 4386void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4387 4388 4389/* 4390** CAPI3REF: Constants Defining Special Destructor Behavior 4391** 4392** These are special values for the destructor that is passed in as the 4393** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4394** argument is SQLITE_STATIC, it means that the content pointer is constant 4395** and will never change. It does not need to be destroyed. ^The 4396** SQLITE_TRANSIENT value means that the content will likely change in 4397** the near future and that SQLite should make its own private copy of 4398** the content before returning. 4399** 4400** The typedef is necessary to work around problems in certain 4401** C++ compilers. 4402*/ 4403typedef void (*sqlite3_destructor_type)(void*); 4404#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4405#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4406 4407/* 4408** CAPI3REF: Setting The Result Of An SQL Function 4409** 4410** These routines are used by the xFunc or xFinal callbacks that 4411** implement SQL functions and aggregates. See 4412** [sqlite3_create_function()] and [sqlite3_create_function16()] 4413** for additional information. 4414** 4415** These functions work very much like the [parameter binding] family of 4416** functions used to bind values to host parameters in prepared statements. 4417** Refer to the [SQL parameter] documentation for additional information. 4418** 4419** ^The sqlite3_result_blob() interface sets the result from 4420** an application-defined function to be the BLOB whose content is pointed 4421** to by the second parameter and which is N bytes long where N is the 4422** third parameter. 4423** 4424** ^The sqlite3_result_zeroblob() interfaces set the result of 4425** the application-defined function to be a BLOB containing all zero 4426** bytes and N bytes in size, where N is the value of the 2nd parameter. 4427** 4428** ^The sqlite3_result_double() interface sets the result from 4429** an application-defined function to be a floating point value specified 4430** by its 2nd argument. 4431** 4432** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4433** cause the implemented SQL function to throw an exception. 4434** ^SQLite uses the string pointed to by the 4435** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4436** as the text of an error message. ^SQLite interprets the error 4437** message string from sqlite3_result_error() as UTF-8. ^SQLite 4438** interprets the string from sqlite3_result_error16() as UTF-16 in native 4439** byte order. ^If the third parameter to sqlite3_result_error() 4440** or sqlite3_result_error16() is negative then SQLite takes as the error 4441** message all text up through the first zero character. 4442** ^If the third parameter to sqlite3_result_error() or 4443** sqlite3_result_error16() is non-negative then SQLite takes that many 4444** bytes (not characters) from the 2nd parameter as the error message. 4445** ^The sqlite3_result_error() and sqlite3_result_error16() 4446** routines make a private copy of the error message text before 4447** they return. Hence, the calling function can deallocate or 4448** modify the text after they return without harm. 4449** ^The sqlite3_result_error_code() function changes the error code 4450** returned by SQLite as a result of an error in a function. ^By default, 4451** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4452** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4453** 4454** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 4455** error indicating that a string or BLOB is too long to represent. 4456** 4457** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 4458** error indicating that a memory allocation failed. 4459** 4460** ^The sqlite3_result_int() interface sets the return value 4461** of the application-defined function to be the 32-bit signed integer 4462** value given in the 2nd argument. 4463** ^The sqlite3_result_int64() interface sets the return value 4464** of the application-defined function to be the 64-bit signed integer 4465** value given in the 2nd argument. 4466** 4467** ^The sqlite3_result_null() interface sets the return value 4468** of the application-defined function to be NULL. 4469** 4470** ^The sqlite3_result_text(), sqlite3_result_text16(), 4471** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4472** set the return value of the application-defined function to be 4473** a text string which is represented as UTF-8, UTF-16 native byte order, 4474** UTF-16 little endian, or UTF-16 big endian, respectively. 4475** ^The sqlite3_result_text64() interface sets the return value of an 4476** application-defined function to be a text string in an encoding 4477** specified by the fifth (and last) parameter, which must be one 4478** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 4479** ^SQLite takes the text result from the application from 4480** the 2nd parameter of the sqlite3_result_text* interfaces. 4481** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4482** is negative, then SQLite takes result text from the 2nd parameter 4483** through the first zero character. 4484** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4485** is non-negative, then as many bytes (not characters) of the text 4486** pointed to by the 2nd parameter are taken as the application-defined 4487** function result. If the 3rd parameter is non-negative, then it 4488** must be the byte offset into the string where the NUL terminator would 4489** appear if the string where NUL terminated. If any NUL characters occur 4490** in the string at a byte offset that is less than the value of the 3rd 4491** parameter, then the resulting string will contain embedded NULs and the 4492** result of expressions operating on strings with embedded NULs is undefined. 4493** ^If the 4th parameter to the sqlite3_result_text* interfaces 4494** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4495** function as the destructor on the text or BLOB result when it has 4496** finished using that result. 4497** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4498** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4499** assumes that the text or BLOB result is in constant space and does not 4500** copy the content of the parameter nor call a destructor on the content 4501** when it has finished using that result. 4502** ^If the 4th parameter to the sqlite3_result_text* interfaces 4503** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4504** then SQLite makes a copy of the result into space obtained from 4505** from [sqlite3_malloc()] before it returns. 4506** 4507** ^The sqlite3_result_value() interface sets the result of 4508** the application-defined function to be a copy the 4509** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4510** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4511** so that the [sqlite3_value] specified in the parameter may change or 4512** be deallocated after sqlite3_result_value() returns without harm. 4513** ^A [protected sqlite3_value] object may always be used where an 4514** [unprotected sqlite3_value] object is required, so either 4515** kind of [sqlite3_value] object can be used with this interface. 4516** 4517** If these routines are called from within the different thread 4518** than the one containing the application-defined function that received 4519** the [sqlite3_context] pointer, the results are undefined. 4520*/ 4521void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4522void sqlite3_result_blob64(sqlite3_context*,const void*, 4523 sqlite3_uint64,void(*)(void*)); 4524void sqlite3_result_double(sqlite3_context*, double); 4525void sqlite3_result_error(sqlite3_context*, const char*, int); 4526void sqlite3_result_error16(sqlite3_context*, const void*, int); 4527void sqlite3_result_error_toobig(sqlite3_context*); 4528void sqlite3_result_error_nomem(sqlite3_context*); 4529void sqlite3_result_error_code(sqlite3_context*, int); 4530void sqlite3_result_int(sqlite3_context*, int); 4531void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4532void sqlite3_result_null(sqlite3_context*); 4533void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4534void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 4535 void(*)(void*), unsigned char encoding); 4536void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4537void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4538void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4539void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4540void sqlite3_result_zeroblob(sqlite3_context*, int n); 4541 4542/* 4543** CAPI3REF: Define New Collating Sequences 4544** 4545** ^These functions add, remove, or modify a [collation] associated 4546** with the [database connection] specified as the first argument. 4547** 4548** ^The name of the collation is a UTF-8 string 4549** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4550** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4551** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4552** considered to be the same name. 4553** 4554** ^(The third argument (eTextRep) must be one of the constants: 4555** <ul> 4556** <li> [SQLITE_UTF8], 4557** <li> [SQLITE_UTF16LE], 4558** <li> [SQLITE_UTF16BE], 4559** <li> [SQLITE_UTF16], or 4560** <li> [SQLITE_UTF16_ALIGNED]. 4561** </ul>)^ 4562** ^The eTextRep argument determines the encoding of strings passed 4563** to the collating function callback, xCallback. 4564** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4565** force strings to be UTF16 with native byte order. 4566** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4567** on an even byte address. 4568** 4569** ^The fourth argument, pArg, is an application data pointer that is passed 4570** through as the first argument to the collating function callback. 4571** 4572** ^The fifth argument, xCallback, is a pointer to the collating function. 4573** ^Multiple collating functions can be registered using the same name but 4574** with different eTextRep parameters and SQLite will use whichever 4575** function requires the least amount of data transformation. 4576** ^If the xCallback argument is NULL then the collating function is 4577** deleted. ^When all collating functions having the same name are deleted, 4578** that collation is no longer usable. 4579** 4580** ^The collating function callback is invoked with a copy of the pArg 4581** application data pointer and with two strings in the encoding specified 4582** by the eTextRep argument. The collating function must return an 4583** integer that is negative, zero, or positive 4584** if the first string is less than, equal to, or greater than the second, 4585** respectively. A collating function must always return the same answer 4586** given the same inputs. If two or more collating functions are registered 4587** to the same collation name (using different eTextRep values) then all 4588** must give an equivalent answer when invoked with equivalent strings. 4589** The collating function must obey the following properties for all 4590** strings A, B, and C: 4591** 4592** <ol> 4593** <li> If A==B then B==A. 4594** <li> If A==B and B==C then A==C. 4595** <li> If A<B THEN B>A. 4596** <li> If A<B and B<C then A<C. 4597** </ol> 4598** 4599** If a collating function fails any of the above constraints and that 4600** collating function is registered and used, then the behavior of SQLite 4601** is undefined. 4602** 4603** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4604** with the addition that the xDestroy callback is invoked on pArg when 4605** the collating function is deleted. 4606** ^Collating functions are deleted when they are overridden by later 4607** calls to the collation creation functions or when the 4608** [database connection] is closed using [sqlite3_close()]. 4609** 4610** ^The xDestroy callback is <u>not</u> called if the 4611** sqlite3_create_collation_v2() function fails. Applications that invoke 4612** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4613** check the return code and dispose of the application data pointer 4614** themselves rather than expecting SQLite to deal with it for them. 4615** This is different from every other SQLite interface. The inconsistency 4616** is unfortunate but cannot be changed without breaking backwards 4617** compatibility. 4618** 4619** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4620*/ 4621int sqlite3_create_collation( 4622 sqlite3*, 4623 const char *zName, 4624 int eTextRep, 4625 void *pArg, 4626 int(*xCompare)(void*,int,const void*,int,const void*) 4627); 4628int sqlite3_create_collation_v2( 4629 sqlite3*, 4630 const char *zName, 4631 int eTextRep, 4632 void *pArg, 4633 int(*xCompare)(void*,int,const void*,int,const void*), 4634 void(*xDestroy)(void*) 4635); 4636int sqlite3_create_collation16( 4637 sqlite3*, 4638 const void *zName, 4639 int eTextRep, 4640 void *pArg, 4641 int(*xCompare)(void*,int,const void*,int,const void*) 4642); 4643 4644/* 4645** CAPI3REF: Collation Needed Callbacks 4646** 4647** ^To avoid having to register all collation sequences before a database 4648** can be used, a single callback function may be registered with the 4649** [database connection] to be invoked whenever an undefined collation 4650** sequence is required. 4651** 4652** ^If the function is registered using the sqlite3_collation_needed() API, 4653** then it is passed the names of undefined collation sequences as strings 4654** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4655** the names are passed as UTF-16 in machine native byte order. 4656** ^A call to either function replaces the existing collation-needed callback. 4657** 4658** ^(When the callback is invoked, the first argument passed is a copy 4659** of the second argument to sqlite3_collation_needed() or 4660** sqlite3_collation_needed16(). The second argument is the database 4661** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4662** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4663** sequence function required. The fourth parameter is the name of the 4664** required collation sequence.)^ 4665** 4666** The callback function should register the desired collation using 4667** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4668** [sqlite3_create_collation_v2()]. 4669*/ 4670int sqlite3_collation_needed( 4671 sqlite3*, 4672 void*, 4673 void(*)(void*,sqlite3*,int eTextRep,const char*) 4674); 4675int sqlite3_collation_needed16( 4676 sqlite3*, 4677 void*, 4678 void(*)(void*,sqlite3*,int eTextRep,const void*) 4679); 4680 4681#ifdef SQLITE_HAS_CODEC 4682/* 4683** Specify the key for an encrypted database. This routine should be 4684** called right after sqlite3_open(). 4685** 4686** The code to implement this API is not available in the public release 4687** of SQLite. 4688*/ 4689int sqlite3_key( 4690 sqlite3 *db, /* Database to be rekeyed */ 4691 const void *pKey, int nKey /* The key */ 4692); 4693int sqlite3_key_v2( 4694 sqlite3 *db, /* Database to be rekeyed */ 4695 const char *zDbName, /* Name of the database */ 4696 const void *pKey, int nKey /* The key */ 4697); 4698 4699/* 4700** Change the key on an open database. If the current database is not 4701** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4702** database is decrypted. 4703** 4704** The code to implement this API is not available in the public release 4705** of SQLite. 4706*/ 4707int sqlite3_rekey( 4708 sqlite3 *db, /* Database to be rekeyed */ 4709 const void *pKey, int nKey /* The new key */ 4710); 4711int sqlite3_rekey_v2( 4712 sqlite3 *db, /* Database to be rekeyed */ 4713 const char *zDbName, /* Name of the database */ 4714 const void *pKey, int nKey /* The new key */ 4715); 4716 4717/* 4718** Specify the activation key for a SEE database. Unless 4719** activated, none of the SEE routines will work. 4720*/ 4721void sqlite3_activate_see( 4722 const char *zPassPhrase /* Activation phrase */ 4723); 4724#endif 4725 4726#ifdef SQLITE_ENABLE_CEROD 4727/* 4728** Specify the activation key for a CEROD database. Unless 4729** activated, none of the CEROD routines will work. 4730*/ 4731void sqlite3_activate_cerod( 4732 const char *zPassPhrase /* Activation phrase */ 4733); 4734#endif 4735 4736/* 4737** CAPI3REF: Suspend Execution For A Short Time 4738** 4739** The sqlite3_sleep() function causes the current thread to suspend execution 4740** for at least a number of milliseconds specified in its parameter. 4741** 4742** If the operating system does not support sleep requests with 4743** millisecond time resolution, then the time will be rounded up to 4744** the nearest second. The number of milliseconds of sleep actually 4745** requested from the operating system is returned. 4746** 4747** ^SQLite implements this interface by calling the xSleep() 4748** method of the default [sqlite3_vfs] object. If the xSleep() method 4749** of the default VFS is not implemented correctly, or not implemented at 4750** all, then the behavior of sqlite3_sleep() may deviate from the description 4751** in the previous paragraphs. 4752*/ 4753int sqlite3_sleep(int); 4754 4755/* 4756** CAPI3REF: Name Of The Folder Holding Temporary Files 4757** 4758** ^(If this global variable is made to point to a string which is 4759** the name of a folder (a.k.a. directory), then all temporary files 4760** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4761** will be placed in that directory.)^ ^If this variable 4762** is a NULL pointer, then SQLite performs a search for an appropriate 4763** temporary file directory. 4764** 4765** Applications are strongly discouraged from using this global variable. 4766** It is required to set a temporary folder on Windows Runtime (WinRT). 4767** But for all other platforms, it is highly recommended that applications 4768** neither read nor write this variable. This global variable is a relic 4769** that exists for backwards compatibility of legacy applications and should 4770** be avoided in new projects. 4771** 4772** It is not safe to read or modify this variable in more than one 4773** thread at a time. It is not safe to read or modify this variable 4774** if a [database connection] is being used at the same time in a separate 4775** thread. 4776** It is intended that this variable be set once 4777** as part of process initialization and before any SQLite interface 4778** routines have been called and that this variable remain unchanged 4779** thereafter. 4780** 4781** ^The [temp_store_directory pragma] may modify this variable and cause 4782** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4783** the [temp_store_directory pragma] always assumes that any string 4784** that this variable points to is held in memory obtained from 4785** [sqlite3_malloc] and the pragma may attempt to free that memory 4786** using [sqlite3_free]. 4787** Hence, if this variable is modified directly, either it should be 4788** made NULL or made to point to memory obtained from [sqlite3_malloc] 4789** or else the use of the [temp_store_directory pragma] should be avoided. 4790** Except when requested by the [temp_store_directory pragma], SQLite 4791** does not free the memory that sqlite3_temp_directory points to. If 4792** the application wants that memory to be freed, it must do 4793** so itself, taking care to only do so after all [database connection] 4794** objects have been destroyed. 4795** 4796** <b>Note to Windows Runtime users:</b> The temporary directory must be set 4797** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 4798** features that require the use of temporary files may fail. Here is an 4799** example of how to do this using C++ with the Windows Runtime: 4800** 4801** <blockquote><pre> 4802** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 4803** TemporaryFolder->Path->Data(); 4804** char zPathBuf[MAX_PATH + 1]; 4805** memset(zPathBuf, 0, sizeof(zPathBuf)); 4806** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 4807** NULL, NULL); 4808** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 4809** </pre></blockquote> 4810*/ 4811SQLITE_EXTERN char *sqlite3_temp_directory; 4812 4813/* 4814** CAPI3REF: Name Of The Folder Holding Database Files 4815** 4816** ^(If this global variable is made to point to a string which is 4817** the name of a folder (a.k.a. directory), then all database files 4818** specified with a relative pathname and created or accessed by 4819** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 4820** to be relative to that directory.)^ ^If this variable is a NULL 4821** pointer, then SQLite assumes that all database files specified 4822** with a relative pathname are relative to the current directory 4823** for the process. Only the windows VFS makes use of this global 4824** variable; it is ignored by the unix VFS. 4825** 4826** Changing the value of this variable while a database connection is 4827** open can result in a corrupt database. 4828** 4829** It is not safe to read or modify this variable in more than one 4830** thread at a time. It is not safe to read or modify this variable 4831** if a [database connection] is being used at the same time in a separate 4832** thread. 4833** It is intended that this variable be set once 4834** as part of process initialization and before any SQLite interface 4835** routines have been called and that this variable remain unchanged 4836** thereafter. 4837** 4838** ^The [data_store_directory pragma] may modify this variable and cause 4839** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4840** the [data_store_directory pragma] always assumes that any string 4841** that this variable points to is held in memory obtained from 4842** [sqlite3_malloc] and the pragma may attempt to free that memory 4843** using [sqlite3_free]. 4844** Hence, if this variable is modified directly, either it should be 4845** made NULL or made to point to memory obtained from [sqlite3_malloc] 4846** or else the use of the [data_store_directory pragma] should be avoided. 4847*/ 4848SQLITE_EXTERN char *sqlite3_data_directory; 4849 4850/* 4851** CAPI3REF: Test For Auto-Commit Mode 4852** KEYWORDS: {autocommit mode} 4853** 4854** ^The sqlite3_get_autocommit() interface returns non-zero or 4855** zero if the given database connection is or is not in autocommit mode, 4856** respectively. ^Autocommit mode is on by default. 4857** ^Autocommit mode is disabled by a [BEGIN] statement. 4858** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 4859** 4860** If certain kinds of errors occur on a statement within a multi-statement 4861** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 4862** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 4863** transaction might be rolled back automatically. The only way to 4864** find out whether SQLite automatically rolled back the transaction after 4865** an error is to use this function. 4866** 4867** If another thread changes the autocommit status of the database 4868** connection while this routine is running, then the return value 4869** is undefined. 4870*/ 4871int sqlite3_get_autocommit(sqlite3*); 4872 4873/* 4874** CAPI3REF: Find The Database Handle Of A Prepared Statement 4875** 4876** ^The sqlite3_db_handle interface returns the [database connection] handle 4877** to which a [prepared statement] belongs. ^The [database connection] 4878** returned by sqlite3_db_handle is the same [database connection] 4879** that was the first argument 4880** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 4881** create the statement in the first place. 4882*/ 4883sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 4884 4885/* 4886** CAPI3REF: Return The Filename For A Database Connection 4887** 4888** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 4889** associated with database N of connection D. ^The main database file 4890** has the name "main". If there is no attached database N on the database 4891** connection D, or if database N is a temporary or in-memory database, then 4892** a NULL pointer is returned. 4893** 4894** ^The filename returned by this function is the output of the 4895** xFullPathname method of the [VFS]. ^In other words, the filename 4896** will be an absolute pathname, even if the filename used 4897** to open the database originally was a URI or relative pathname. 4898*/ 4899const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 4900 4901/* 4902** CAPI3REF: Determine if a database is read-only 4903** 4904** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 4905** of connection D is read-only, 0 if it is read/write, or -1 if N is not 4906** the name of a database on connection D. 4907*/ 4908int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 4909 4910/* 4911** CAPI3REF: Find the next prepared statement 4912** 4913** ^This interface returns a pointer to the next [prepared statement] after 4914** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 4915** then this interface returns a pointer to the first prepared statement 4916** associated with the database connection pDb. ^If no prepared statement 4917** satisfies the conditions of this routine, it returns NULL. 4918** 4919** The [database connection] pointer D in a call to 4920** [sqlite3_next_stmt(D,S)] must refer to an open database 4921** connection and in particular must not be a NULL pointer. 4922*/ 4923sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 4924 4925/* 4926** CAPI3REF: Commit And Rollback Notification Callbacks 4927** 4928** ^The sqlite3_commit_hook() interface registers a callback 4929** function to be invoked whenever a transaction is [COMMIT | committed]. 4930** ^Any callback set by a previous call to sqlite3_commit_hook() 4931** for the same database connection is overridden. 4932** ^The sqlite3_rollback_hook() interface registers a callback 4933** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 4934** ^Any callback set by a previous call to sqlite3_rollback_hook() 4935** for the same database connection is overridden. 4936** ^The pArg argument is passed through to the callback. 4937** ^If the callback on a commit hook function returns non-zero, 4938** then the commit is converted into a rollback. 4939** 4940** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 4941** return the P argument from the previous call of the same function 4942** on the same [database connection] D, or NULL for 4943** the first call for each function on D. 4944** 4945** The commit and rollback hook callbacks are not reentrant. 4946** The callback implementation must not do anything that will modify 4947** the database connection that invoked the callback. Any actions 4948** to modify the database connection must be deferred until after the 4949** completion of the [sqlite3_step()] call that triggered the commit 4950** or rollback hook in the first place. 4951** Note that running any other SQL statements, including SELECT statements, 4952** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 4953** the database connections for the meaning of "modify" in this paragraph. 4954** 4955** ^Registering a NULL function disables the callback. 4956** 4957** ^When the commit hook callback routine returns zero, the [COMMIT] 4958** operation is allowed to continue normally. ^If the commit hook 4959** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 4960** ^The rollback hook is invoked on a rollback that results from a commit 4961** hook returning non-zero, just as it would be with any other rollback. 4962** 4963** ^For the purposes of this API, a transaction is said to have been 4964** rolled back if an explicit "ROLLBACK" statement is executed, or 4965** an error or constraint causes an implicit rollback to occur. 4966** ^The rollback callback is not invoked if a transaction is 4967** automatically rolled back because the database connection is closed. 4968** 4969** See also the [sqlite3_update_hook()] interface. 4970*/ 4971void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 4972void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 4973 4974/* 4975** CAPI3REF: Data Change Notification Callbacks 4976** 4977** ^The sqlite3_update_hook() interface registers a callback function 4978** with the [database connection] identified by the first argument 4979** to be invoked whenever a row is updated, inserted or deleted in 4980** a rowid table. 4981** ^Any callback set by a previous call to this function 4982** for the same database connection is overridden. 4983** 4984** ^The second argument is a pointer to the function to invoke when a 4985** row is updated, inserted or deleted in a rowid table. 4986** ^The first argument to the callback is a copy of the third argument 4987** to sqlite3_update_hook(). 4988** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 4989** or [SQLITE_UPDATE], depending on the operation that caused the callback 4990** to be invoked. 4991** ^The third and fourth arguments to the callback contain pointers to the 4992** database and table name containing the affected row. 4993** ^The final callback parameter is the [rowid] of the row. 4994** ^In the case of an update, this is the [rowid] after the update takes place. 4995** 4996** ^(The update hook is not invoked when internal system tables are 4997** modified (i.e. sqlite_master and sqlite_sequence).)^ 4998** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 4999** 5000** ^In the current implementation, the update hook 5001** is not invoked when duplication rows are deleted because of an 5002** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5003** invoked when rows are deleted using the [truncate optimization]. 5004** The exceptions defined in this paragraph might change in a future 5005** release of SQLite. 5006** 5007** The update hook implementation must not do anything that will modify 5008** the database connection that invoked the update hook. Any actions 5009** to modify the database connection must be deferred until after the 5010** completion of the [sqlite3_step()] call that triggered the update hook. 5011** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5012** database connections for the meaning of "modify" in this paragraph. 5013** 5014** ^The sqlite3_update_hook(D,C,P) function 5015** returns the P argument from the previous call 5016** on the same [database connection] D, or NULL for 5017** the first call on D. 5018** 5019** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 5020** interfaces. 5021*/ 5022void *sqlite3_update_hook( 5023 sqlite3*, 5024 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5025 void* 5026); 5027 5028/* 5029** CAPI3REF: Enable Or Disable Shared Pager Cache 5030** 5031** ^(This routine enables or disables the sharing of the database cache 5032** and schema data structures between [database connection | connections] 5033** to the same database. Sharing is enabled if the argument is true 5034** and disabled if the argument is false.)^ 5035** 5036** ^Cache sharing is enabled and disabled for an entire process. 5037** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 5038** sharing was enabled or disabled for each thread separately. 5039** 5040** ^(The cache sharing mode set by this interface effects all subsequent 5041** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5042** Existing database connections continue use the sharing mode 5043** that was in effect at the time they were opened.)^ 5044** 5045** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5046** successfully. An [error code] is returned otherwise.)^ 5047** 5048** ^Shared cache is disabled by default. But this might change in 5049** future releases of SQLite. Applications that care about shared 5050** cache setting should set it explicitly. 5051** 5052** This interface is threadsafe on processors where writing a 5053** 32-bit integer is atomic. 5054** 5055** See Also: [SQLite Shared-Cache Mode] 5056*/ 5057int sqlite3_enable_shared_cache(int); 5058 5059/* 5060** CAPI3REF: Attempt To Free Heap Memory 5061** 5062** ^The sqlite3_release_memory() interface attempts to free N bytes 5063** of heap memory by deallocating non-essential memory allocations 5064** held by the database library. Memory used to cache database 5065** pages to improve performance is an example of non-essential memory. 5066** ^sqlite3_release_memory() returns the number of bytes actually freed, 5067** which might be more or less than the amount requested. 5068** ^The sqlite3_release_memory() routine is a no-op returning zero 5069** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5070** 5071** See also: [sqlite3_db_release_memory()] 5072*/ 5073int sqlite3_release_memory(int); 5074 5075/* 5076** CAPI3REF: Free Memory Used By A Database Connection 5077** 5078** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5079** memory as possible from database connection D. Unlike the 5080** [sqlite3_release_memory()] interface, this interface is in effect even 5081** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5082** omitted. 5083** 5084** See also: [sqlite3_release_memory()] 5085*/ 5086int sqlite3_db_release_memory(sqlite3*); 5087 5088/* 5089** CAPI3REF: Impose A Limit On Heap Size 5090** 5091** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5092** soft limit on the amount of heap memory that may be allocated by SQLite. 5093** ^SQLite strives to keep heap memory utilization below the soft heap 5094** limit by reducing the number of pages held in the page cache 5095** as heap memory usages approaches the limit. 5096** ^The soft heap limit is "soft" because even though SQLite strives to stay 5097** below the limit, it will exceed the limit rather than generate 5098** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5099** is advisory only. 5100** 5101** ^The return value from sqlite3_soft_heap_limit64() is the size of 5102** the soft heap limit prior to the call, or negative in the case of an 5103** error. ^If the argument N is negative 5104** then no change is made to the soft heap limit. Hence, the current 5105** size of the soft heap limit can be determined by invoking 5106** sqlite3_soft_heap_limit64() with a negative argument. 5107** 5108** ^If the argument N is zero then the soft heap limit is disabled. 5109** 5110** ^(The soft heap limit is not enforced in the current implementation 5111** if one or more of following conditions are true: 5112** 5113** <ul> 5114** <li> The soft heap limit is set to zero. 5115** <li> Memory accounting is disabled using a combination of the 5116** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5117** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5118** <li> An alternative page cache implementation is specified using 5119** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5120** <li> The page cache allocates from its own memory pool supplied 5121** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5122** from the heap. 5123** </ul>)^ 5124** 5125** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 5126** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5127** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5128** the soft heap limit is enforced on every memory allocation. Without 5129** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5130** when memory is allocated by the page cache. Testing suggests that because 5131** the page cache is the predominate memory user in SQLite, most 5132** applications will achieve adequate soft heap limit enforcement without 5133** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5134** 5135** The circumstances under which SQLite will enforce the soft heap limit may 5136** changes in future releases of SQLite. 5137*/ 5138sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5139 5140/* 5141** CAPI3REF: Deprecated Soft Heap Limit Interface 5142** DEPRECATED 5143** 5144** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5145** interface. This routine is provided for historical compatibility 5146** only. All new applications should use the 5147** [sqlite3_soft_heap_limit64()] interface rather than this one. 5148*/ 5149SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5150 5151 5152/* 5153** CAPI3REF: Extract Metadata About A Column Of A Table 5154** 5155** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5156** information about column C of table T in database D 5157** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5158** interface returns SQLITE_OK and fills in the non-NULL pointers in 5159** the final five arguments with appropriate values if the specified 5160** column exists. ^The sqlite3_table_column_metadata() interface returns 5161** SQLITE_ERROR and if the specified column does not exist. 5162** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5163** NULL pointer, then this routine simply checks for the existance of the 5164** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5165** does not. 5166** 5167** ^The column is identified by the second, third and fourth parameters to 5168** this function. ^(The second parameter is either the name of the database 5169** (i.e. "main", "temp", or an attached database) containing the specified 5170** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5171** for the table using the same algorithm used by the database engine to 5172** resolve unqualified table references. 5173** 5174** ^The third and fourth parameters to this function are the table and column 5175** name of the desired column, respectively. 5176** 5177** ^Metadata is returned by writing to the memory locations passed as the 5th 5178** and subsequent parameters to this function. ^Any of these arguments may be 5179** NULL, in which case the corresponding element of metadata is omitted. 5180** 5181** ^(<blockquote> 5182** <table border="1"> 5183** <tr><th> Parameter <th> Output<br>Type <th> Description 5184** 5185** <tr><td> 5th <td> const char* <td> Data type 5186** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5187** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5188** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5189** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5190** </table> 5191** </blockquote>)^ 5192** 5193** ^The memory pointed to by the character pointers returned for the 5194** declaration type and collation sequence is valid until the next 5195** call to any SQLite API function. 5196** 5197** ^If the specified table is actually a view, an [error code] is returned. 5198** 5199** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5200** is not a [WITHOUT ROWID] table and an 5201** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5202** parameters are set for the explicitly declared column. ^(If there is no 5203** [INTEGER PRIMARY KEY] column, then the outputs 5204** for the [rowid] are set as follows: 5205** 5206** <pre> 5207** data type: "INTEGER" 5208** collation sequence: "BINARY" 5209** not null: 0 5210** primary key: 1 5211** auto increment: 0 5212** </pre>)^ 5213** 5214** ^This function causes all database schemas to be read from disk and 5215** parsed, if that has not already been done, and returns an error if 5216** any errors are encountered while loading the schema. 5217*/ 5218int sqlite3_table_column_metadata( 5219 sqlite3 *db, /* Connection handle */ 5220 const char *zDbName, /* Database name or NULL */ 5221 const char *zTableName, /* Table name */ 5222 const char *zColumnName, /* Column name */ 5223 char const **pzDataType, /* OUTPUT: Declared data type */ 5224 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5225 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5226 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5227 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5228); 5229 5230/* 5231** CAPI3REF: Load An Extension 5232** 5233** ^This interface loads an SQLite extension library from the named file. 5234** 5235** ^The sqlite3_load_extension() interface attempts to load an 5236** [SQLite extension] library contained in the file zFile. If 5237** the file cannot be loaded directly, attempts are made to load 5238** with various operating-system specific extensions added. 5239** So for example, if "samplelib" cannot be loaded, then names like 5240** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5241** be tried also. 5242** 5243** ^The entry point is zProc. 5244** ^(zProc may be 0, in which case SQLite will try to come up with an 5245** entry point name on its own. It first tries "sqlite3_extension_init". 5246** If that does not work, it constructs a name "sqlite3_X_init" where the 5247** X is consists of the lower-case equivalent of all ASCII alphabetic 5248** characters in the filename from the last "/" to the first following 5249** "." and omitting any initial "lib".)^ 5250** ^The sqlite3_load_extension() interface returns 5251** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5252** ^If an error occurs and pzErrMsg is not 0, then the 5253** [sqlite3_load_extension()] interface shall attempt to 5254** fill *pzErrMsg with error message text stored in memory 5255** obtained from [sqlite3_malloc()]. The calling function 5256** should free this memory by calling [sqlite3_free()]. 5257** 5258** ^Extension loading must be enabled using 5259** [sqlite3_enable_load_extension()] prior to calling this API, 5260** otherwise an error will be returned. 5261** 5262** See also the [load_extension() SQL function]. 5263*/ 5264int sqlite3_load_extension( 5265 sqlite3 *db, /* Load the extension into this database connection */ 5266 const char *zFile, /* Name of the shared library containing extension */ 5267 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5268 char **pzErrMsg /* Put error message here if not 0 */ 5269); 5270 5271/* 5272** CAPI3REF: Enable Or Disable Extension Loading 5273** 5274** ^So as not to open security holes in older applications that are 5275** unprepared to deal with [extension loading], and as a means of disabling 5276** [extension loading] while evaluating user-entered SQL, the following API 5277** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5278** 5279** ^Extension loading is off by default. 5280** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5281** to turn extension loading on and call it with onoff==0 to turn 5282** it back off again. 5283*/ 5284int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5285 5286/* 5287** CAPI3REF: Automatically Load Statically Linked Extensions 5288** 5289** ^This interface causes the xEntryPoint() function to be invoked for 5290** each new [database connection] that is created. The idea here is that 5291** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5292** that is to be automatically loaded into all new database connections. 5293** 5294** ^(Even though the function prototype shows that xEntryPoint() takes 5295** no arguments and returns void, SQLite invokes xEntryPoint() with three 5296** arguments and expects and integer result as if the signature of the 5297** entry point where as follows: 5298** 5299** <blockquote><pre> 5300** int xEntryPoint( 5301** sqlite3 *db, 5302** const char **pzErrMsg, 5303** const struct sqlite3_api_routines *pThunk 5304** ); 5305** </pre></blockquote>)^ 5306** 5307** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5308** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5309** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5310** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5311** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5312** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5313** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 5314** 5315** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 5316** on the list of automatic extensions is a harmless no-op. ^No entry point 5317** will be called more than once for each database connection that is opened. 5318** 5319** See also: [sqlite3_reset_auto_extension()] 5320** and [sqlite3_cancel_auto_extension()] 5321*/ 5322int sqlite3_auto_extension(void (*xEntryPoint)(void)); 5323 5324/* 5325** CAPI3REF: Cancel Automatic Extension Loading 5326** 5327** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 5328** initialization routine X that was registered using a prior call to 5329** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 5330** routine returns 1 if initialization routine X was successfully 5331** unregistered and it returns 0 if X was not on the list of initialization 5332** routines. 5333*/ 5334int sqlite3_cancel_auto_extension(void (*xEntryPoint)(void)); 5335 5336/* 5337** CAPI3REF: Reset Automatic Extension Loading 5338** 5339** ^This interface disables all automatic extensions previously 5340** registered using [sqlite3_auto_extension()]. 5341*/ 5342void sqlite3_reset_auto_extension(void); 5343 5344/* 5345** The interface to the virtual-table mechanism is currently considered 5346** to be experimental. The interface might change in incompatible ways. 5347** If this is a problem for you, do not use the interface at this time. 5348** 5349** When the virtual-table mechanism stabilizes, we will declare the 5350** interface fixed, support it indefinitely, and remove this comment. 5351*/ 5352 5353/* 5354** Structures used by the virtual table interface 5355*/ 5356typedef struct sqlite3_vtab sqlite3_vtab; 5357typedef struct sqlite3_index_info sqlite3_index_info; 5358typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 5359typedef struct sqlite3_module sqlite3_module; 5360 5361/* 5362** CAPI3REF: Virtual Table Object 5363** KEYWORDS: sqlite3_module {virtual table module} 5364** 5365** This structure, sometimes called a "virtual table module", 5366** defines the implementation of a [virtual tables]. 5367** This structure consists mostly of methods for the module. 5368** 5369** ^A virtual table module is created by filling in a persistent 5370** instance of this structure and passing a pointer to that instance 5371** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 5372** ^The registration remains valid until it is replaced by a different 5373** module or until the [database connection] closes. The content 5374** of this structure must not change while it is registered with 5375** any database connection. 5376*/ 5377struct sqlite3_module { 5378 int iVersion; 5379 int (*xCreate)(sqlite3*, void *pAux, 5380 int argc, const char *const*argv, 5381 sqlite3_vtab **ppVTab, char**); 5382 int (*xConnect)(sqlite3*, void *pAux, 5383 int argc, const char *const*argv, 5384 sqlite3_vtab **ppVTab, char**); 5385 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 5386 int (*xDisconnect)(sqlite3_vtab *pVTab); 5387 int (*xDestroy)(sqlite3_vtab *pVTab); 5388 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 5389 int (*xClose)(sqlite3_vtab_cursor*); 5390 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 5391 int argc, sqlite3_value **argv); 5392 int (*xNext)(sqlite3_vtab_cursor*); 5393 int (*xEof)(sqlite3_vtab_cursor*); 5394 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 5395 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 5396 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 5397 int (*xBegin)(sqlite3_vtab *pVTab); 5398 int (*xSync)(sqlite3_vtab *pVTab); 5399 int (*xCommit)(sqlite3_vtab *pVTab); 5400 int (*xRollback)(sqlite3_vtab *pVTab); 5401 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 5402 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 5403 void **ppArg); 5404 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 5405 /* The methods above are in version 1 of the sqlite_module object. Those 5406 ** below are for version 2 and greater. */ 5407 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 5408 int (*xRelease)(sqlite3_vtab *pVTab, int); 5409 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 5410}; 5411 5412/* 5413** CAPI3REF: Virtual Table Indexing Information 5414** KEYWORDS: sqlite3_index_info 5415** 5416** The sqlite3_index_info structure and its substructures is used as part 5417** of the [virtual table] interface to 5418** pass information into and receive the reply from the [xBestIndex] 5419** method of a [virtual table module]. The fields under **Inputs** are the 5420** inputs to xBestIndex and are read-only. xBestIndex inserts its 5421** results into the **Outputs** fields. 5422** 5423** ^(The aConstraint[] array records WHERE clause constraints of the form: 5424** 5425** <blockquote>column OP expr</blockquote> 5426** 5427** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 5428** stored in aConstraint[].op using one of the 5429** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 5430** ^(The index of the column is stored in 5431** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5432** expr on the right-hand side can be evaluated (and thus the constraint 5433** is usable) and false if it cannot.)^ 5434** 5435** ^The optimizer automatically inverts terms of the form "expr OP column" 5436** and makes other simplifications to the WHERE clause in an attempt to 5437** get as many WHERE clause terms into the form shown above as possible. 5438** ^The aConstraint[] array only reports WHERE clause terms that are 5439** relevant to the particular virtual table being queried. 5440** 5441** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5442** ^Each term of aOrderBy records a column of the ORDER BY clause. 5443** 5444** The [xBestIndex] method must fill aConstraintUsage[] with information 5445** about what parameters to pass to xFilter. ^If argvIndex>0 then 5446** the right-hand side of the corresponding aConstraint[] is evaluated 5447** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5448** is true, then the constraint is assumed to be fully handled by the 5449** virtual table and is not checked again by SQLite.)^ 5450** 5451** ^The idxNum and idxPtr values are recorded and passed into the 5452** [xFilter] method. 5453** ^[sqlite3_free()] is used to free idxPtr if and only if 5454** needToFreeIdxPtr is true. 5455** 5456** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5457** the correct order to satisfy the ORDER BY clause so that no separate 5458** sorting step is required. 5459** 5460** ^The estimatedCost value is an estimate of the cost of a particular 5461** strategy. A cost of N indicates that the cost of the strategy is similar 5462** to a linear scan of an SQLite table with N rows. A cost of log(N) 5463** indicates that the expense of the operation is similar to that of a 5464** binary search on a unique indexed field of an SQLite table with N rows. 5465** 5466** ^The estimatedRows value is an estimate of the number of rows that 5467** will be returned by the strategy. 5468** 5469** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 5470** structure for SQLite version 3.8.2. If a virtual table extension is 5471** used with an SQLite version earlier than 3.8.2, the results of attempting 5472** to read or write the estimatedRows field are undefined (but are likely 5473** to included crashing the application). The estimatedRows field should 5474** therefore only be used if [sqlite3_libversion_number()] returns a 5475** value greater than or equal to 3008002. 5476*/ 5477struct sqlite3_index_info { 5478 /* Inputs */ 5479 int nConstraint; /* Number of entries in aConstraint */ 5480 struct sqlite3_index_constraint { 5481 int iColumn; /* Column on left-hand side of constraint */ 5482 unsigned char op; /* Constraint operator */ 5483 unsigned char usable; /* True if this constraint is usable */ 5484 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5485 } *aConstraint; /* Table of WHERE clause constraints */ 5486 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5487 struct sqlite3_index_orderby { 5488 int iColumn; /* Column number */ 5489 unsigned char desc; /* True for DESC. False for ASC. */ 5490 } *aOrderBy; /* The ORDER BY clause */ 5491 /* Outputs */ 5492 struct sqlite3_index_constraint_usage { 5493 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5494 unsigned char omit; /* Do not code a test for this constraint */ 5495 } *aConstraintUsage; 5496 int idxNum; /* Number used to identify the index */ 5497 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5498 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5499 int orderByConsumed; /* True if output is already ordered */ 5500 double estimatedCost; /* Estimated cost of using this index */ 5501 /* Fields below are only available in SQLite 3.8.2 and later */ 5502 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 5503}; 5504 5505/* 5506** CAPI3REF: Virtual Table Constraint Operator Codes 5507** 5508** These macros defined the allowed values for the 5509** [sqlite3_index_info].aConstraint[].op field. Each value represents 5510** an operator that is part of a constraint term in the wHERE clause of 5511** a query that uses a [virtual table]. 5512*/ 5513#define SQLITE_INDEX_CONSTRAINT_EQ 2 5514#define SQLITE_INDEX_CONSTRAINT_GT 4 5515#define SQLITE_INDEX_CONSTRAINT_LE 8 5516#define SQLITE_INDEX_CONSTRAINT_LT 16 5517#define SQLITE_INDEX_CONSTRAINT_GE 32 5518#define SQLITE_INDEX_CONSTRAINT_MATCH 64 5519 5520/* 5521** CAPI3REF: Register A Virtual Table Implementation 5522** 5523** ^These routines are used to register a new [virtual table module] name. 5524** ^Module names must be registered before 5525** creating a new [virtual table] using the module and before using a 5526** preexisting [virtual table] for the module. 5527** 5528** ^The module name is registered on the [database connection] specified 5529** by the first parameter. ^The name of the module is given by the 5530** second parameter. ^The third parameter is a pointer to 5531** the implementation of the [virtual table module]. ^The fourth 5532** parameter is an arbitrary client data pointer that is passed through 5533** into the [xCreate] and [xConnect] methods of the virtual table module 5534** when a new virtual table is be being created or reinitialized. 5535** 5536** ^The sqlite3_create_module_v2() interface has a fifth parameter which 5537** is a pointer to a destructor for the pClientData. ^SQLite will 5538** invoke the destructor function (if it is not NULL) when SQLite 5539** no longer needs the pClientData pointer. ^The destructor will also 5540** be invoked if the call to sqlite3_create_module_v2() fails. 5541** ^The sqlite3_create_module() 5542** interface is equivalent to sqlite3_create_module_v2() with a NULL 5543** destructor. 5544*/ 5545int sqlite3_create_module( 5546 sqlite3 *db, /* SQLite connection to register module with */ 5547 const char *zName, /* Name of the module */ 5548 const sqlite3_module *p, /* Methods for the module */ 5549 void *pClientData /* Client data for xCreate/xConnect */ 5550); 5551int sqlite3_create_module_v2( 5552 sqlite3 *db, /* SQLite connection to register module with */ 5553 const char *zName, /* Name of the module */ 5554 const sqlite3_module *p, /* Methods for the module */ 5555 void *pClientData, /* Client data for xCreate/xConnect */ 5556 void(*xDestroy)(void*) /* Module destructor function */ 5557); 5558 5559/* 5560** CAPI3REF: Virtual Table Instance Object 5561** KEYWORDS: sqlite3_vtab 5562** 5563** Every [virtual table module] implementation uses a subclass 5564** of this object to describe a particular instance 5565** of the [virtual table]. Each subclass will 5566** be tailored to the specific needs of the module implementation. 5567** The purpose of this superclass is to define certain fields that are 5568** common to all module implementations. 5569** 5570** ^Virtual tables methods can set an error message by assigning a 5571** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 5572** take care that any prior string is freed by a call to [sqlite3_free()] 5573** prior to assigning a new string to zErrMsg. ^After the error message 5574** is delivered up to the client application, the string will be automatically 5575** freed by sqlite3_free() and the zErrMsg field will be zeroed. 5576*/ 5577struct sqlite3_vtab { 5578 const sqlite3_module *pModule; /* The module for this virtual table */ 5579 int nRef; /* NO LONGER USED */ 5580 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 5581 /* Virtual table implementations will typically add additional fields */ 5582}; 5583 5584/* 5585** CAPI3REF: Virtual Table Cursor Object 5586** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 5587** 5588** Every [virtual table module] implementation uses a subclass of the 5589** following structure to describe cursors that point into the 5590** [virtual table] and are used 5591** to loop through the virtual table. Cursors are created using the 5592** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 5593** by the [sqlite3_module.xClose | xClose] method. Cursors are used 5594** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 5595** of the module. Each module implementation will define 5596** the content of a cursor structure to suit its own needs. 5597** 5598** This superclass exists in order to define fields of the cursor that 5599** are common to all implementations. 5600*/ 5601struct sqlite3_vtab_cursor { 5602 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 5603 /* Virtual table implementations will typically add additional fields */ 5604}; 5605 5606/* 5607** CAPI3REF: Declare The Schema Of A Virtual Table 5608** 5609** ^The [xCreate] and [xConnect] methods of a 5610** [virtual table module] call this interface 5611** to declare the format (the names and datatypes of the columns) of 5612** the virtual tables they implement. 5613*/ 5614int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 5615 5616/* 5617** CAPI3REF: Overload A Function For A Virtual Table 5618** 5619** ^(Virtual tables can provide alternative implementations of functions 5620** using the [xFindFunction] method of the [virtual table module]. 5621** But global versions of those functions 5622** must exist in order to be overloaded.)^ 5623** 5624** ^(This API makes sure a global version of a function with a particular 5625** name and number of parameters exists. If no such function exists 5626** before this API is called, a new function is created.)^ ^The implementation 5627** of the new function always causes an exception to be thrown. So 5628** the new function is not good for anything by itself. Its only 5629** purpose is to be a placeholder function that can be overloaded 5630** by a [virtual table]. 5631*/ 5632int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5633 5634/* 5635** The interface to the virtual-table mechanism defined above (back up 5636** to a comment remarkably similar to this one) is currently considered 5637** to be experimental. The interface might change in incompatible ways. 5638** If this is a problem for you, do not use the interface at this time. 5639** 5640** When the virtual-table mechanism stabilizes, we will declare the 5641** interface fixed, support it indefinitely, and remove this comment. 5642*/ 5643 5644/* 5645** CAPI3REF: A Handle To An Open BLOB 5646** KEYWORDS: {BLOB handle} {BLOB handles} 5647** 5648** An instance of this object represents an open BLOB on which 5649** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5650** ^Objects of this type are created by [sqlite3_blob_open()] 5651** and destroyed by [sqlite3_blob_close()]. 5652** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5653** can be used to read or write small subsections of the BLOB. 5654** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5655*/ 5656typedef struct sqlite3_blob sqlite3_blob; 5657 5658/* 5659** CAPI3REF: Open A BLOB For Incremental I/O 5660** 5661** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5662** in row iRow, column zColumn, table zTable in database zDb; 5663** in other words, the same BLOB that would be selected by: 5664** 5665** <pre> 5666** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5667** </pre>)^ 5668** 5669** ^(Parameter zDb is not the filename that contains the database, but 5670** rather the symbolic name of the database. For attached databases, this is 5671** the name that appears after the AS keyword in the [ATTACH] statement. 5672** For the main database file, the database name is "main". For TEMP 5673** tables, the database name is "temp".)^ 5674** 5675** ^If the flags parameter is non-zero, then the BLOB is opened for read 5676** and write access. ^If the flags parameter is zero, the BLOB is opened for 5677** read-only access. 5678** 5679** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 5680** in *ppBlob. Otherwise an [error code] is returned and, unless the error 5681** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 5682** the API is not misused, it is always safe to call [sqlite3_blob_close()] 5683** on *ppBlob after this function it returns. 5684** 5685** This function fails with SQLITE_ERROR if any of the following are true: 5686** <ul> 5687** <li> ^(Database zDb does not exist)^, 5688** <li> ^(Table zTable does not exist within database zDb)^, 5689** <li> ^(Table zTable is a WITHOUT ROWID table)^, 5690** <li> ^(Column zColumn does not exist)^, 5691** <li> ^(Row iRow is not present in the table)^, 5692** <li> ^(The specified column of row iRow contains a value that is not 5693** a TEXT or BLOB value)^, 5694** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 5695** constraint and the blob is being opened for read/write access)^, 5696** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 5697** column zColumn is part of a [child key] definition and the blob is 5698** being opened for read/write access)^. 5699** </ul> 5700** 5701** ^Unless it returns SQLITE_MISUSE, this function sets the 5702** [database connection] error code and message accessible via 5703** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 5704** 5705** 5706** ^(If the row that a BLOB handle points to is modified by an 5707** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5708** then the BLOB handle is marked as "expired". 5709** This is true if any column of the row is changed, even a column 5710** other than the one the BLOB handle is open on.)^ 5711** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5712** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5713** ^(Changes written into a BLOB prior to the BLOB expiring are not 5714** rolled back by the expiration of the BLOB. Such changes will eventually 5715** commit if the transaction continues to completion.)^ 5716** 5717** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5718** the opened blob. ^The size of a blob may not be changed by this 5719** interface. Use the [UPDATE] SQL command to change the size of a 5720** blob. 5721** 5722** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5723** and the built-in [zeroblob] SQL function may be used to create a 5724** zero-filled blob to read or write using the incremental-blob interface. 5725** 5726** To avoid a resource leak, every open [BLOB handle] should eventually 5727** be released by a call to [sqlite3_blob_close()]. 5728*/ 5729int sqlite3_blob_open( 5730 sqlite3*, 5731 const char *zDb, 5732 const char *zTable, 5733 const char *zColumn, 5734 sqlite3_int64 iRow, 5735 int flags, 5736 sqlite3_blob **ppBlob 5737); 5738 5739/* 5740** CAPI3REF: Move a BLOB Handle to a New Row 5741** 5742** ^This function is used to move an existing blob handle so that it points 5743** to a different row of the same database table. ^The new row is identified 5744** by the rowid value passed as the second argument. Only the row can be 5745** changed. ^The database, table and column on which the blob handle is open 5746** remain the same. Moving an existing blob handle to a new row can be 5747** faster than closing the existing handle and opening a new one. 5748** 5749** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5750** it must exist and there must be either a blob or text value stored in 5751** the nominated column.)^ ^If the new row is not present in the table, or if 5752** it does not contain a blob or text value, or if another error occurs, an 5753** SQLite error code is returned and the blob handle is considered aborted. 5754** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5755** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5756** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5757** always returns zero. 5758** 5759** ^This function sets the database handle error code and message. 5760*/ 5761SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5762 5763/* 5764** CAPI3REF: Close A BLOB Handle 5765** 5766** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 5767** unconditionally. Even if this routine returns an error code, the 5768** handle is still closed.)^ 5769** 5770** ^If the blob handle being closed was opened for read-write access, and if 5771** the database is in auto-commit mode and there are no other open read-write 5772** blob handles or active write statements, the current transaction is 5773** committed. ^If an error occurs while committing the transaction, an error 5774** code is returned and the transaction rolled back. 5775** 5776** Calling this function with an argument that is not a NULL pointer or an 5777** open blob handle results in undefined behaviour. ^Calling this routine 5778** with a null pointer (such as would be returned by a failed call to 5779** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 5780** is passed a valid open blob handle, the values returned by the 5781** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 5782*/ 5783int sqlite3_blob_close(sqlite3_blob *); 5784 5785/* 5786** CAPI3REF: Return The Size Of An Open BLOB 5787** 5788** ^Returns the size in bytes of the BLOB accessible via the 5789** successfully opened [BLOB handle] in its only argument. ^The 5790** incremental blob I/O routines can only read or overwriting existing 5791** blob content; they cannot change the size of a blob. 5792** 5793** This routine only works on a [BLOB handle] which has been created 5794** by a prior successful call to [sqlite3_blob_open()] and which has not 5795** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5796** to this routine results in undefined and probably undesirable behavior. 5797*/ 5798int sqlite3_blob_bytes(sqlite3_blob *); 5799 5800/* 5801** CAPI3REF: Read Data From A BLOB Incrementally 5802** 5803** ^(This function is used to read data from an open [BLOB handle] into a 5804** caller-supplied buffer. N bytes of data are copied into buffer Z 5805** from the open BLOB, starting at offset iOffset.)^ 5806** 5807** ^If offset iOffset is less than N bytes from the end of the BLOB, 5808** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 5809** less than zero, [SQLITE_ERROR] is returned and no data is read. 5810** ^The size of the blob (and hence the maximum value of N+iOffset) 5811** can be determined using the [sqlite3_blob_bytes()] interface. 5812** 5813** ^An attempt to read from an expired [BLOB handle] fails with an 5814** error code of [SQLITE_ABORT]. 5815** 5816** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 5817** Otherwise, an [error code] or an [extended error code] is returned.)^ 5818** 5819** This routine only works on a [BLOB handle] which has been created 5820** by a prior successful call to [sqlite3_blob_open()] and which has not 5821** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5822** to this routine results in undefined and probably undesirable behavior. 5823** 5824** See also: [sqlite3_blob_write()]. 5825*/ 5826int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 5827 5828/* 5829** CAPI3REF: Write Data Into A BLOB Incrementally 5830** 5831** ^(This function is used to write data into an open [BLOB handle] from a 5832** caller-supplied buffer. N bytes of data are copied from the buffer Z 5833** into the open BLOB, starting at offset iOffset.)^ 5834** 5835** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 5836** Otherwise, an [error code] or an [extended error code] is returned.)^ 5837** ^Unless SQLITE_MISUSE is returned, this function sets the 5838** [database connection] error code and message accessible via 5839** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 5840** 5841** ^If the [BLOB handle] passed as the first argument was not opened for 5842** writing (the flags parameter to [sqlite3_blob_open()] was zero), 5843** this function returns [SQLITE_READONLY]. 5844** 5845** This function may only modify the contents of the BLOB; it is 5846** not possible to increase the size of a BLOB using this API. 5847** ^If offset iOffset is less than N bytes from the end of the BLOB, 5848** [SQLITE_ERROR] is returned and no data is written. The size of the 5849** BLOB (and hence the maximum value of N+iOffset) can be determined 5850** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 5851** than zero [SQLITE_ERROR] is returned and no data is written. 5852** 5853** ^An attempt to write to an expired [BLOB handle] fails with an 5854** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 5855** before the [BLOB handle] expired are not rolled back by the 5856** expiration of the handle, though of course those changes might 5857** have been overwritten by the statement that expired the BLOB handle 5858** or by other independent statements. 5859** 5860** This routine only works on a [BLOB handle] which has been created 5861** by a prior successful call to [sqlite3_blob_open()] and which has not 5862** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5863** to this routine results in undefined and probably undesirable behavior. 5864** 5865** See also: [sqlite3_blob_read()]. 5866*/ 5867int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 5868 5869/* 5870** CAPI3REF: Virtual File System Objects 5871** 5872** A virtual filesystem (VFS) is an [sqlite3_vfs] object 5873** that SQLite uses to interact 5874** with the underlying operating system. Most SQLite builds come with a 5875** single default VFS that is appropriate for the host computer. 5876** New VFSes can be registered and existing VFSes can be unregistered. 5877** The following interfaces are provided. 5878** 5879** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 5880** ^Names are case sensitive. 5881** ^Names are zero-terminated UTF-8 strings. 5882** ^If there is no match, a NULL pointer is returned. 5883** ^If zVfsName is NULL then the default VFS is returned. 5884** 5885** ^New VFSes are registered with sqlite3_vfs_register(). 5886** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 5887** ^The same VFS can be registered multiple times without injury. 5888** ^To make an existing VFS into the default VFS, register it again 5889** with the makeDflt flag set. If two different VFSes with the 5890** same name are registered, the behavior is undefined. If a 5891** VFS is registered with a name that is NULL or an empty string, 5892** then the behavior is undefined. 5893** 5894** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 5895** ^(If the default VFS is unregistered, another VFS is chosen as 5896** the default. The choice for the new VFS is arbitrary.)^ 5897*/ 5898sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 5899int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 5900int sqlite3_vfs_unregister(sqlite3_vfs*); 5901 5902/* 5903** CAPI3REF: Mutexes 5904** 5905** The SQLite core uses these routines for thread 5906** synchronization. Though they are intended for internal 5907** use by SQLite, code that links against SQLite is 5908** permitted to use any of these routines. 5909** 5910** The SQLite source code contains multiple implementations 5911** of these mutex routines. An appropriate implementation 5912** is selected automatically at compile-time. The following 5913** implementations are available in the SQLite core: 5914** 5915** <ul> 5916** <li> SQLITE_MUTEX_PTHREADS 5917** <li> SQLITE_MUTEX_W32 5918** <li> SQLITE_MUTEX_NOOP 5919** </ul> 5920** 5921** The SQLITE_MUTEX_NOOP implementation is a set of routines 5922** that does no real locking and is appropriate for use in 5923** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 5924** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 5925** and Windows. 5926** 5927** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 5928** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 5929** implementation is included with the library. In this case the 5930** application must supply a custom mutex implementation using the 5931** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 5932** before calling sqlite3_initialize() or any other public sqlite3_ 5933** function that calls sqlite3_initialize(). 5934** 5935** ^The sqlite3_mutex_alloc() routine allocates a new 5936** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 5937** routine returns NULL if it is unable to allocate the requested 5938** mutex. The argument to sqlite3_mutex_alloc() must one of these 5939** integer constants: 5940** 5941** <ul> 5942** <li> SQLITE_MUTEX_FAST 5943** <li> SQLITE_MUTEX_RECURSIVE 5944** <li> SQLITE_MUTEX_STATIC_MASTER 5945** <li> SQLITE_MUTEX_STATIC_MEM 5946** <li> SQLITE_MUTEX_STATIC_OPEN 5947** <li> SQLITE_MUTEX_STATIC_PRNG 5948** <li> SQLITE_MUTEX_STATIC_LRU 5949** <li> SQLITE_MUTEX_STATIC_PMEM 5950** <li> SQLITE_MUTEX_STATIC_APP1 5951** <li> SQLITE_MUTEX_STATIC_APP2 5952** <li> SQLITE_MUTEX_STATIC_APP3 5953** </ul> 5954** 5955** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 5956** cause sqlite3_mutex_alloc() to create 5957** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 5958** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 5959** The mutex implementation does not need to make a distinction 5960** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 5961** not want to. SQLite will only request a recursive mutex in 5962** cases where it really needs one. If a faster non-recursive mutex 5963** implementation is available on the host platform, the mutex subsystem 5964** might return such a mutex in response to SQLITE_MUTEX_FAST. 5965** 5966** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 5967** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 5968** a pointer to a static preexisting mutex. ^Nine static mutexes are 5969** used by the current version of SQLite. Future versions of SQLite 5970** may add additional static mutexes. Static mutexes are for internal 5971** use by SQLite only. Applications that use SQLite mutexes should 5972** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 5973** SQLITE_MUTEX_RECURSIVE. 5974** 5975** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 5976** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 5977** returns a different mutex on every call. ^For the static 5978** mutex types, the same mutex is returned on every call that has 5979** the same type number. 5980** 5981** ^The sqlite3_mutex_free() routine deallocates a previously 5982** allocated dynamic mutex. Attempting to deallocate a static 5983** mutex results in undefined behavior. 5984** 5985** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 5986** to enter a mutex. ^If another thread is already within the mutex, 5987** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 5988** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 5989** upon successful entry. ^(Mutexes created using 5990** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 5991** In such cases, the 5992** mutex must be exited an equal number of times before another thread 5993** can enter.)^ If the same thread tries to enter any mutex other 5994** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 5995** 5996** ^(Some systems (for example, Windows 95) do not support the operation 5997** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 5998** will always return SQLITE_BUSY. The SQLite core only ever uses 5999** sqlite3_mutex_try() as an optimization so this is acceptable 6000** behavior.)^ 6001** 6002** ^The sqlite3_mutex_leave() routine exits a mutex that was 6003** previously entered by the same thread. The behavior 6004** is undefined if the mutex is not currently entered by the 6005** calling thread or is not currently allocated. 6006** 6007** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6008** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6009** behave as no-ops. 6010** 6011** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6012*/ 6013sqlite3_mutex *sqlite3_mutex_alloc(int); 6014void sqlite3_mutex_free(sqlite3_mutex*); 6015void sqlite3_mutex_enter(sqlite3_mutex*); 6016int sqlite3_mutex_try(sqlite3_mutex*); 6017void sqlite3_mutex_leave(sqlite3_mutex*); 6018 6019/* 6020** CAPI3REF: Mutex Methods Object 6021** 6022** An instance of this structure defines the low-level routines 6023** used to allocate and use mutexes. 6024** 6025** Usually, the default mutex implementations provided by SQLite are 6026** sufficient, however the application has the option of substituting a custom 6027** implementation for specialized deployments or systems for which SQLite 6028** does not provide a suitable implementation. In this case, the application 6029** creates and populates an instance of this structure to pass 6030** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6031** Additionally, an instance of this structure can be used as an 6032** output variable when querying the system for the current mutex 6033** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6034** 6035** ^The xMutexInit method defined by this structure is invoked as 6036** part of system initialization by the sqlite3_initialize() function. 6037** ^The xMutexInit routine is called by SQLite exactly once for each 6038** effective call to [sqlite3_initialize()]. 6039** 6040** ^The xMutexEnd method defined by this structure is invoked as 6041** part of system shutdown by the sqlite3_shutdown() function. The 6042** implementation of this method is expected to release all outstanding 6043** resources obtained by the mutex methods implementation, especially 6044** those obtained by the xMutexInit method. ^The xMutexEnd() 6045** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6046** 6047** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6048** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6049** xMutexNotheld) implement the following interfaces (respectively): 6050** 6051** <ul> 6052** <li> [sqlite3_mutex_alloc()] </li> 6053** <li> [sqlite3_mutex_free()] </li> 6054** <li> [sqlite3_mutex_enter()] </li> 6055** <li> [sqlite3_mutex_try()] </li> 6056** <li> [sqlite3_mutex_leave()] </li> 6057** <li> [sqlite3_mutex_held()] </li> 6058** <li> [sqlite3_mutex_notheld()] </li> 6059** </ul>)^ 6060** 6061** The only difference is that the public sqlite3_XXX functions enumerated 6062** above silently ignore any invocations that pass a NULL pointer instead 6063** of a valid mutex handle. The implementations of the methods defined 6064** by this structure are not required to handle this case, the results 6065** of passing a NULL pointer instead of a valid mutex handle are undefined 6066** (i.e. it is acceptable to provide an implementation that segfaults if 6067** it is passed a NULL pointer). 6068** 6069** The xMutexInit() method must be threadsafe. It must be harmless to 6070** invoke xMutexInit() multiple times within the same process and without 6071** intervening calls to xMutexEnd(). Second and subsequent calls to 6072** xMutexInit() must be no-ops. 6073** 6074** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6075** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6076** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6077** memory allocation for a fast or recursive mutex. 6078** 6079** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6080** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6081** If xMutexInit fails in any way, it is expected to clean up after itself 6082** prior to returning. 6083*/ 6084typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6085struct sqlite3_mutex_methods { 6086 int (*xMutexInit)(void); 6087 int (*xMutexEnd)(void); 6088 sqlite3_mutex *(*xMutexAlloc)(int); 6089 void (*xMutexFree)(sqlite3_mutex *); 6090 void (*xMutexEnter)(sqlite3_mutex *); 6091 int (*xMutexTry)(sqlite3_mutex *); 6092 void (*xMutexLeave)(sqlite3_mutex *); 6093 int (*xMutexHeld)(sqlite3_mutex *); 6094 int (*xMutexNotheld)(sqlite3_mutex *); 6095}; 6096 6097/* 6098** CAPI3REF: Mutex Verification Routines 6099** 6100** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6101** are intended for use inside assert() statements. The SQLite core 6102** never uses these routines except inside an assert() and applications 6103** are advised to follow the lead of the core. The SQLite core only 6104** provides implementations for these routines when it is compiled 6105** with the SQLITE_DEBUG flag. External mutex implementations 6106** are only required to provide these routines if SQLITE_DEBUG is 6107** defined and if NDEBUG is not defined. 6108** 6109** These routines should return true if the mutex in their argument 6110** is held or not held, respectively, by the calling thread. 6111** 6112** The implementation is not required to provide versions of these 6113** routines that actually work. If the implementation does not provide working 6114** versions of these routines, it should at least provide stubs that always 6115** return true so that one does not get spurious assertion failures. 6116** 6117** If the argument to sqlite3_mutex_held() is a NULL pointer then 6118** the routine should return 1. This seems counter-intuitive since 6119** clearly the mutex cannot be held if it does not exist. But 6120** the reason the mutex does not exist is because the build is not 6121** using mutexes. And we do not want the assert() containing the 6122** call to sqlite3_mutex_held() to fail, so a non-zero return is 6123** the appropriate thing to do. The sqlite3_mutex_notheld() 6124** interface should also return 1 when given a NULL pointer. 6125*/ 6126#ifndef NDEBUG 6127int sqlite3_mutex_held(sqlite3_mutex*); 6128int sqlite3_mutex_notheld(sqlite3_mutex*); 6129#endif 6130 6131/* 6132** CAPI3REF: Mutex Types 6133** 6134** The [sqlite3_mutex_alloc()] interface takes a single argument 6135** which is one of these integer constants. 6136** 6137** The set of static mutexes may change from one SQLite release to the 6138** next. Applications that override the built-in mutex logic must be 6139** prepared to accommodate additional static mutexes. 6140*/ 6141#define SQLITE_MUTEX_FAST 0 6142#define SQLITE_MUTEX_RECURSIVE 1 6143#define SQLITE_MUTEX_STATIC_MASTER 2 6144#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6145#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6146#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6147#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 6148#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6149#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6150#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6151#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6152#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6153#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6154 6155/* 6156** CAPI3REF: Retrieve the mutex for a database connection 6157** 6158** ^This interface returns a pointer the [sqlite3_mutex] object that 6159** serializes access to the [database connection] given in the argument 6160** when the [threading mode] is Serialized. 6161** ^If the [threading mode] is Single-thread or Multi-thread then this 6162** routine returns a NULL pointer. 6163*/ 6164sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 6165 6166/* 6167** CAPI3REF: Low-Level Control Of Database Files 6168** 6169** ^The [sqlite3_file_control()] interface makes a direct call to the 6170** xFileControl method for the [sqlite3_io_methods] object associated 6171** with a particular database identified by the second argument. ^The 6172** name of the database is "main" for the main database or "temp" for the 6173** TEMP database, or the name that appears after the AS keyword for 6174** databases that are added using the [ATTACH] SQL command. 6175** ^A NULL pointer can be used in place of "main" to refer to the 6176** main database file. 6177** ^The third and fourth parameters to this routine 6178** are passed directly through to the second and third parameters of 6179** the xFileControl method. ^The return value of the xFileControl 6180** method becomes the return value of this routine. 6181** 6182** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 6183** a pointer to the underlying [sqlite3_file] object to be written into 6184** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 6185** case is a short-circuit path which does not actually invoke the 6186** underlying sqlite3_io_methods.xFileControl method. 6187** 6188** ^If the second parameter (zDbName) does not match the name of any 6189** open database file, then SQLITE_ERROR is returned. ^This error 6190** code is not remembered and will not be recalled by [sqlite3_errcode()] 6191** or [sqlite3_errmsg()]. The underlying xFileControl method might 6192** also return SQLITE_ERROR. There is no way to distinguish between 6193** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6194** xFileControl method. 6195** 6196** See also: [SQLITE_FCNTL_LOCKSTATE] 6197*/ 6198int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6199 6200/* 6201** CAPI3REF: Testing Interface 6202** 6203** ^The sqlite3_test_control() interface is used to read out internal 6204** state of SQLite and to inject faults into SQLite for testing 6205** purposes. ^The first parameter is an operation code that determines 6206** the number, meaning, and operation of all subsequent parameters. 6207** 6208** This interface is not for use by applications. It exists solely 6209** for verifying the correct operation of the SQLite library. Depending 6210** on how the SQLite library is compiled, this interface might not exist. 6211** 6212** The details of the operation codes, their meanings, the parameters 6213** they take, and what they do are all subject to change without notice. 6214** Unlike most of the SQLite API, this function is not guaranteed to 6215** operate consistently from one release to the next. 6216*/ 6217int sqlite3_test_control(int op, ...); 6218 6219/* 6220** CAPI3REF: Testing Interface Operation Codes 6221** 6222** These constants are the valid operation code parameters used 6223** as the first argument to [sqlite3_test_control()]. 6224** 6225** These parameters and their meanings are subject to change 6226** without notice. These values are for testing purposes only. 6227** Applications should not use any of these parameters or the 6228** [sqlite3_test_control()] interface. 6229*/ 6230#define SQLITE_TESTCTRL_FIRST 5 6231#define SQLITE_TESTCTRL_PRNG_SAVE 5 6232#define SQLITE_TESTCTRL_PRNG_RESTORE 6 6233#define SQLITE_TESTCTRL_PRNG_RESET 7 6234#define SQLITE_TESTCTRL_BITVEC_TEST 8 6235#define SQLITE_TESTCTRL_FAULT_INSTALL 9 6236#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 6237#define SQLITE_TESTCTRL_PENDING_BYTE 11 6238#define SQLITE_TESTCTRL_ASSERT 12 6239#define SQLITE_TESTCTRL_ALWAYS 13 6240#define SQLITE_TESTCTRL_RESERVE 14 6241#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 6242#define SQLITE_TESTCTRL_ISKEYWORD 16 6243#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 6244#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 6245#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 6246#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 6247#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 6248#define SQLITE_TESTCTRL_BYTEORDER 22 6249#define SQLITE_TESTCTRL_ISINIT 23 6250#define SQLITE_TESTCTRL_SORTER_MMAP 24 6251#define SQLITE_TESTCTRL_LAST 24 6252 6253/* 6254** CAPI3REF: SQLite Runtime Status 6255** 6256** ^This interface is used to retrieve runtime status information 6257** about the performance of SQLite, and optionally to reset various 6258** highwater marks. ^The first argument is an integer code for 6259** the specific parameter to measure. ^(Recognized integer codes 6260** are of the form [status parameters | SQLITE_STATUS_...].)^ 6261** ^The current value of the parameter is returned into *pCurrent. 6262** ^The highest recorded value is returned in *pHighwater. ^If the 6263** resetFlag is true, then the highest record value is reset after 6264** *pHighwater is written. ^(Some parameters do not record the highest 6265** value. For those parameters 6266** nothing is written into *pHighwater and the resetFlag is ignored.)^ 6267** ^(Other parameters record only the highwater mark and not the current 6268** value. For these latter parameters nothing is written into *pCurrent.)^ 6269** 6270** ^The sqlite3_status() routine returns SQLITE_OK on success and a 6271** non-zero [error code] on failure. 6272** 6273** This routine is threadsafe but is not atomic. This routine can be 6274** called while other threads are running the same or different SQLite 6275** interfaces. However the values returned in *pCurrent and 6276** *pHighwater reflect the status of SQLite at different points in time 6277** and it is possible that another thread might change the parameter 6278** in between the times when *pCurrent and *pHighwater are written. 6279** 6280** See also: [sqlite3_db_status()] 6281*/ 6282int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 6283 6284 6285/* 6286** CAPI3REF: Status Parameters 6287** KEYWORDS: {status parameters} 6288** 6289** These integer constants designate various run-time status parameters 6290** that can be returned by [sqlite3_status()]. 6291** 6292** <dl> 6293** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 6294** <dd>This parameter is the current amount of memory checked out 6295** using [sqlite3_malloc()], either directly or indirectly. The 6296** figure includes calls made to [sqlite3_malloc()] by the application 6297** and internal memory usage by the SQLite library. Scratch memory 6298** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 6299** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 6300** this parameter. The amount returned is the sum of the allocation 6301** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 6302** 6303** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 6304** <dd>This parameter records the largest memory allocation request 6305** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 6306** internal equivalents). Only the value returned in the 6307** *pHighwater parameter to [sqlite3_status()] is of interest. 6308** The value written into the *pCurrent parameter is undefined.</dd>)^ 6309** 6310** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 6311** <dd>This parameter records the number of separate memory allocations 6312** currently checked out.</dd>)^ 6313** 6314** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 6315** <dd>This parameter returns the number of pages used out of the 6316** [pagecache memory allocator] that was configured using 6317** [SQLITE_CONFIG_PAGECACHE]. The 6318** value returned is in pages, not in bytes.</dd>)^ 6319** 6320** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 6321** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 6322** <dd>This parameter returns the number of bytes of page cache 6323** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 6324** buffer and where forced to overflow to [sqlite3_malloc()]. The 6325** returned value includes allocations that overflowed because they 6326** where too large (they were larger than the "sz" parameter to 6327** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 6328** no space was left in the page cache.</dd>)^ 6329** 6330** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 6331** <dd>This parameter records the largest memory allocation request 6332** handed to [pagecache memory allocator]. Only the value returned in the 6333** *pHighwater parameter to [sqlite3_status()] is of interest. 6334** The value written into the *pCurrent parameter is undefined.</dd>)^ 6335** 6336** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 6337** <dd>This parameter returns the number of allocations used out of the 6338** [scratch memory allocator] configured using 6339** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 6340** in bytes. Since a single thread may only have one scratch allocation 6341** outstanding at time, this parameter also reports the number of threads 6342** using scratch memory at the same time.</dd>)^ 6343** 6344** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 6345** <dd>This parameter returns the number of bytes of scratch memory 6346** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 6347** buffer and where forced to overflow to [sqlite3_malloc()]. The values 6348** returned include overflows because the requested allocation was too 6349** larger (that is, because the requested allocation was larger than the 6350** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 6351** slots were available. 6352** </dd>)^ 6353** 6354** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 6355** <dd>This parameter records the largest memory allocation request 6356** handed to [scratch memory allocator]. Only the value returned in the 6357** *pHighwater parameter to [sqlite3_status()] is of interest. 6358** The value written into the *pCurrent parameter is undefined.</dd>)^ 6359** 6360** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 6361** <dd>This parameter records the deepest parser stack. It is only 6362** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 6363** </dl> 6364** 6365** New status parameters may be added from time to time. 6366*/ 6367#define SQLITE_STATUS_MEMORY_USED 0 6368#define SQLITE_STATUS_PAGECACHE_USED 1 6369#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 6370#define SQLITE_STATUS_SCRATCH_USED 3 6371#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 6372#define SQLITE_STATUS_MALLOC_SIZE 5 6373#define SQLITE_STATUS_PARSER_STACK 6 6374#define SQLITE_STATUS_PAGECACHE_SIZE 7 6375#define SQLITE_STATUS_SCRATCH_SIZE 8 6376#define SQLITE_STATUS_MALLOC_COUNT 9 6377 6378/* 6379** CAPI3REF: Database Connection Status 6380** 6381** ^This interface is used to retrieve runtime status information 6382** about a single [database connection]. ^The first argument is the 6383** database connection object to be interrogated. ^The second argument 6384** is an integer constant, taken from the set of 6385** [SQLITE_DBSTATUS options], that 6386** determines the parameter to interrogate. The set of 6387** [SQLITE_DBSTATUS options] is likely 6388** to grow in future releases of SQLite. 6389** 6390** ^The current value of the requested parameter is written into *pCur 6391** and the highest instantaneous value is written into *pHiwtr. ^If 6392** the resetFlg is true, then the highest instantaneous value is 6393** reset back down to the current value. 6394** 6395** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 6396** non-zero [error code] on failure. 6397** 6398** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 6399*/ 6400int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 6401 6402/* 6403** CAPI3REF: Status Parameters for database connections 6404** KEYWORDS: {SQLITE_DBSTATUS options} 6405** 6406** These constants are the available integer "verbs" that can be passed as 6407** the second argument to the [sqlite3_db_status()] interface. 6408** 6409** New verbs may be added in future releases of SQLite. Existing verbs 6410** might be discontinued. Applications should check the return code from 6411** [sqlite3_db_status()] to make sure that the call worked. 6412** The [sqlite3_db_status()] interface will return a non-zero error code 6413** if a discontinued or unsupported verb is invoked. 6414** 6415** <dl> 6416** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 6417** <dd>This parameter returns the number of lookaside memory slots currently 6418** checked out.</dd>)^ 6419** 6420** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 6421** <dd>This parameter returns the number malloc attempts that were 6422** satisfied using lookaside memory. Only the high-water value is meaningful; 6423** the current value is always zero.)^ 6424** 6425** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 6426** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 6427** <dd>This parameter returns the number malloc attempts that might have 6428** been satisfied using lookaside memory but failed due to the amount of 6429** memory requested being larger than the lookaside slot size. 6430** Only the high-water value is meaningful; 6431** the current value is always zero.)^ 6432** 6433** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 6434** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 6435** <dd>This parameter returns the number malloc attempts that might have 6436** been satisfied using lookaside memory but failed due to all lookaside 6437** memory already being in use. 6438** Only the high-water value is meaningful; 6439** the current value is always zero.)^ 6440** 6441** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 6442** <dd>This parameter returns the approximate number of bytes of heap 6443** memory used by all pager caches associated with the database connection.)^ 6444** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 6445** 6446** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 6447** <dd>This parameter returns the approximate number of bytes of heap 6448** memory used to store the schema for all databases associated 6449** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 6450** ^The full amount of memory used by the schemas is reported, even if the 6451** schema memory is shared with other database connections due to 6452** [shared cache mode] being enabled. 6453** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 6454** 6455** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 6456** <dd>This parameter returns the approximate number of bytes of heap 6457** and lookaside memory used by all prepared statements associated with 6458** the database connection.)^ 6459** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 6460** </dd> 6461** 6462** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 6463** <dd>This parameter returns the number of pager cache hits that have 6464** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 6465** is always 0. 6466** </dd> 6467** 6468** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6469** <dd>This parameter returns the number of pager cache misses that have 6470** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6471** is always 0. 6472** </dd> 6473** 6474** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 6475** <dd>This parameter returns the number of dirty cache entries that have 6476** been written to disk. Specifically, the number of pages written to the 6477** wal file in wal mode databases, or the number of pages written to the 6478** database file in rollback mode databases. Any pages written as part of 6479** transaction rollback or database recovery operations are not included. 6480** If an IO or other error occurs while writing a page to disk, the effect 6481** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 6482** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 6483** </dd> 6484** 6485** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 6486** <dd>This parameter returns zero for the current value if and only if 6487** all foreign key constraints (deferred or immediate) have been 6488** resolved.)^ ^The highwater mark is always 0. 6489** </dd> 6490** </dl> 6491*/ 6492#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6493#define SQLITE_DBSTATUS_CACHE_USED 1 6494#define SQLITE_DBSTATUS_SCHEMA_USED 2 6495#define SQLITE_DBSTATUS_STMT_USED 3 6496#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6497#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6498#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 6499#define SQLITE_DBSTATUS_CACHE_HIT 7 6500#define SQLITE_DBSTATUS_CACHE_MISS 8 6501#define SQLITE_DBSTATUS_CACHE_WRITE 9 6502#define SQLITE_DBSTATUS_DEFERRED_FKS 10 6503#define SQLITE_DBSTATUS_MAX 10 /* Largest defined DBSTATUS */ 6504 6505 6506/* 6507** CAPI3REF: Prepared Statement Status 6508** 6509** ^(Each prepared statement maintains various 6510** [SQLITE_STMTSTATUS counters] that measure the number 6511** of times it has performed specific operations.)^ These counters can 6512** be used to monitor the performance characteristics of the prepared 6513** statements. For example, if the number of table steps greatly exceeds 6514** the number of table searches or result rows, that would tend to indicate 6515** that the prepared statement is using a full table scan rather than 6516** an index. 6517** 6518** ^(This interface is used to retrieve and reset counter values from 6519** a [prepared statement]. The first argument is the prepared statement 6520** object to be interrogated. The second argument 6521** is an integer code for a specific [SQLITE_STMTSTATUS counter] 6522** to be interrogated.)^ 6523** ^The current value of the requested counter is returned. 6524** ^If the resetFlg is true, then the counter is reset to zero after this 6525** interface call returns. 6526** 6527** See also: [sqlite3_status()] and [sqlite3_db_status()]. 6528*/ 6529int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 6530 6531/* 6532** CAPI3REF: Status Parameters for prepared statements 6533** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 6534** 6535** These preprocessor macros define integer codes that name counter 6536** values associated with the [sqlite3_stmt_status()] interface. 6537** The meanings of the various counters are as follows: 6538** 6539** <dl> 6540** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 6541** <dd>^This is the number of times that SQLite has stepped forward in 6542** a table as part of a full table scan. Large numbers for this counter 6543** may indicate opportunities for performance improvement through 6544** careful use of indices.</dd> 6545** 6546** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 6547** <dd>^This is the number of sort operations that have occurred. 6548** A non-zero value in this counter may indicate an opportunity to 6549** improvement performance through careful use of indices.</dd> 6550** 6551** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 6552** <dd>^This is the number of rows inserted into transient indices that 6553** were created automatically in order to help joins run faster. 6554** A non-zero value in this counter may indicate an opportunity to 6555** improvement performance by adding permanent indices that do not 6556** need to be reinitialized each time the statement is run.</dd> 6557** 6558** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 6559** <dd>^This is the number of virtual machine operations executed 6560** by the prepared statement if that number is less than or equal 6561** to 2147483647. The number of virtual machine operations can be 6562** used as a proxy for the total work done by the prepared statement. 6563** If the number of virtual machine operations exceeds 2147483647 6564** then the value returned by this statement status code is undefined. 6565** </dd> 6566** </dl> 6567*/ 6568#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 6569#define SQLITE_STMTSTATUS_SORT 2 6570#define SQLITE_STMTSTATUS_AUTOINDEX 3 6571#define SQLITE_STMTSTATUS_VM_STEP 4 6572 6573/* 6574** CAPI3REF: Custom Page Cache Object 6575** 6576** The sqlite3_pcache type is opaque. It is implemented by 6577** the pluggable module. The SQLite core has no knowledge of 6578** its size or internal structure and never deals with the 6579** sqlite3_pcache object except by holding and passing pointers 6580** to the object. 6581** 6582** See [sqlite3_pcache_methods2] for additional information. 6583*/ 6584typedef struct sqlite3_pcache sqlite3_pcache; 6585 6586/* 6587** CAPI3REF: Custom Page Cache Object 6588** 6589** The sqlite3_pcache_page object represents a single page in the 6590** page cache. The page cache will allocate instances of this 6591** object. Various methods of the page cache use pointers to instances 6592** of this object as parameters or as their return value. 6593** 6594** See [sqlite3_pcache_methods2] for additional information. 6595*/ 6596typedef struct sqlite3_pcache_page sqlite3_pcache_page; 6597struct sqlite3_pcache_page { 6598 void *pBuf; /* The content of the page */ 6599 void *pExtra; /* Extra information associated with the page */ 6600}; 6601 6602/* 6603** CAPI3REF: Application Defined Page Cache. 6604** KEYWORDS: {page cache} 6605** 6606** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 6607** register an alternative page cache implementation by passing in an 6608** instance of the sqlite3_pcache_methods2 structure.)^ 6609** In many applications, most of the heap memory allocated by 6610** SQLite is used for the page cache. 6611** By implementing a 6612** custom page cache using this API, an application can better control 6613** the amount of memory consumed by SQLite, the way in which 6614** that memory is allocated and released, and the policies used to 6615** determine exactly which parts of a database file are cached and for 6616** how long. 6617** 6618** The alternative page cache mechanism is an 6619** extreme measure that is only needed by the most demanding applications. 6620** The built-in page cache is recommended for most uses. 6621** 6622** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 6623** internal buffer by SQLite within the call to [sqlite3_config]. Hence 6624** the application may discard the parameter after the call to 6625** [sqlite3_config()] returns.)^ 6626** 6627** [[the xInit() page cache method]] 6628** ^(The xInit() method is called once for each effective 6629** call to [sqlite3_initialize()])^ 6630** (usually only once during the lifetime of the process). ^(The xInit() 6631** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 6632** The intent of the xInit() method is to set up global data structures 6633** required by the custom page cache implementation. 6634** ^(If the xInit() method is NULL, then the 6635** built-in default page cache is used instead of the application defined 6636** page cache.)^ 6637** 6638** [[the xShutdown() page cache method]] 6639** ^The xShutdown() method is called by [sqlite3_shutdown()]. 6640** It can be used to clean up 6641** any outstanding resources before process shutdown, if required. 6642** ^The xShutdown() method may be NULL. 6643** 6644** ^SQLite automatically serializes calls to the xInit method, 6645** so the xInit method need not be threadsafe. ^The 6646** xShutdown method is only called from [sqlite3_shutdown()] so it does 6647** not need to be threadsafe either. All other methods must be threadsafe 6648** in multithreaded applications. 6649** 6650** ^SQLite will never invoke xInit() more than once without an intervening 6651** call to xShutdown(). 6652** 6653** [[the xCreate() page cache methods]] 6654** ^SQLite invokes the xCreate() method to construct a new cache instance. 6655** SQLite will typically create one cache instance for each open database file, 6656** though this is not guaranteed. ^The 6657** first parameter, szPage, is the size in bytes of the pages that must 6658** be allocated by the cache. ^szPage will always a power of two. ^The 6659** second parameter szExtra is a number of bytes of extra storage 6660** associated with each page cache entry. ^The szExtra parameter will 6661** a number less than 250. SQLite will use the 6662** extra szExtra bytes on each page to store metadata about the underlying 6663** database page on disk. The value passed into szExtra depends 6664** on the SQLite version, the target platform, and how SQLite was compiled. 6665** ^The third argument to xCreate(), bPurgeable, is true if the cache being 6666** created will be used to cache database pages of a file stored on disk, or 6667** false if it is used for an in-memory database. The cache implementation 6668** does not have to do anything special based with the value of bPurgeable; 6669** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 6670** never invoke xUnpin() except to deliberately delete a page. 6671** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 6672** false will always have the "discard" flag set to true. 6673** ^Hence, a cache created with bPurgeable false will 6674** never contain any unpinned pages. 6675** 6676** [[the xCachesize() page cache method]] 6677** ^(The xCachesize() method may be called at any time by SQLite to set the 6678** suggested maximum cache-size (number of pages stored by) the cache 6679** instance passed as the first argument. This is the value configured using 6680** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 6681** parameter, the implementation is not required to do anything with this 6682** value; it is advisory only. 6683** 6684** [[the xPagecount() page cache methods]] 6685** The xPagecount() method must return the number of pages currently 6686** stored in the cache, both pinned and unpinned. 6687** 6688** [[the xFetch() page cache methods]] 6689** The xFetch() method locates a page in the cache and returns a pointer to 6690** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 6691** The pBuf element of the returned sqlite3_pcache_page object will be a 6692** pointer to a buffer of szPage bytes used to store the content of a 6693** single database page. The pExtra element of sqlite3_pcache_page will be 6694** a pointer to the szExtra bytes of extra storage that SQLite has requested 6695** for each entry in the page cache. 6696** 6697** The page to be fetched is determined by the key. ^The minimum key value 6698** is 1. After it has been retrieved using xFetch, the page is considered 6699** to be "pinned". 6700** 6701** If the requested page is already in the page cache, then the page cache 6702** implementation must return a pointer to the page buffer with its content 6703** intact. If the requested page is not already in the cache, then the 6704** cache implementation should use the value of the createFlag 6705** parameter to help it determined what action to take: 6706** 6707** <table border=1 width=85% align=center> 6708** <tr><th> createFlag <th> Behavior when page is not already in cache 6709** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6710** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6711** Otherwise return NULL. 6712** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6713** NULL if allocating a new page is effectively impossible. 6714** </table> 6715** 6716** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6717** will only use a createFlag of 2 after a prior call with a createFlag of 1 6718** failed.)^ In between the to xFetch() calls, SQLite may 6719** attempt to unpin one or more cache pages by spilling the content of 6720** pinned pages to disk and synching the operating system disk cache. 6721** 6722** [[the xUnpin() page cache method]] 6723** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6724** as its second argument. If the third parameter, discard, is non-zero, 6725** then the page must be evicted from the cache. 6726** ^If the discard parameter is 6727** zero, then the page may be discarded or retained at the discretion of 6728** page cache implementation. ^The page cache implementation 6729** may choose to evict unpinned pages at any time. 6730** 6731** The cache must not perform any reference counting. A single 6732** call to xUnpin() unpins the page regardless of the number of prior calls 6733** to xFetch(). 6734** 6735** [[the xRekey() page cache methods]] 6736** The xRekey() method is used to change the key value associated with the 6737** page passed as the second argument. If the cache 6738** previously contains an entry associated with newKey, it must be 6739** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6740** to be pinned. 6741** 6742** When SQLite calls the xTruncate() method, the cache must discard all 6743** existing cache entries with page numbers (keys) greater than or equal 6744** to the value of the iLimit parameter passed to xTruncate(). If any 6745** of these pages are pinned, they are implicitly unpinned, meaning that 6746** they can be safely discarded. 6747** 6748** [[the xDestroy() page cache method]] 6749** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6750** All resources associated with the specified cache should be freed. ^After 6751** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6752** handle invalid, and will not use it with any other sqlite3_pcache_methods2 6753** functions. 6754** 6755** [[the xShrink() page cache method]] 6756** ^SQLite invokes the xShrink() method when it wants the page cache to 6757** free up as much of heap memory as possible. The page cache implementation 6758** is not obligated to free any memory, but well-behaved implementations should 6759** do their best. 6760*/ 6761typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 6762struct sqlite3_pcache_methods2 { 6763 int iVersion; 6764 void *pArg; 6765 int (*xInit)(void*); 6766 void (*xShutdown)(void*); 6767 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 6768 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6769 int (*xPagecount)(sqlite3_pcache*); 6770 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6771 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 6772 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 6773 unsigned oldKey, unsigned newKey); 6774 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6775 void (*xDestroy)(sqlite3_pcache*); 6776 void (*xShrink)(sqlite3_pcache*); 6777}; 6778 6779/* 6780** This is the obsolete pcache_methods object that has now been replaced 6781** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 6782** retained in the header file for backwards compatibility only. 6783*/ 6784typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 6785struct sqlite3_pcache_methods { 6786 void *pArg; 6787 int (*xInit)(void*); 6788 void (*xShutdown)(void*); 6789 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 6790 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6791 int (*xPagecount)(sqlite3_pcache*); 6792 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6793 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 6794 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 6795 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6796 void (*xDestroy)(sqlite3_pcache*); 6797}; 6798 6799 6800/* 6801** CAPI3REF: Online Backup Object 6802** 6803** The sqlite3_backup object records state information about an ongoing 6804** online backup operation. ^The sqlite3_backup object is created by 6805** a call to [sqlite3_backup_init()] and is destroyed by a call to 6806** [sqlite3_backup_finish()]. 6807** 6808** See Also: [Using the SQLite Online Backup API] 6809*/ 6810typedef struct sqlite3_backup sqlite3_backup; 6811 6812/* 6813** CAPI3REF: Online Backup API. 6814** 6815** The backup API copies the content of one database into another. 6816** It is useful either for creating backups of databases or 6817** for copying in-memory databases to or from persistent files. 6818** 6819** See Also: [Using the SQLite Online Backup API] 6820** 6821** ^SQLite holds a write transaction open on the destination database file 6822** for the duration of the backup operation. 6823** ^The source database is read-locked only while it is being read; 6824** it is not locked continuously for the entire backup operation. 6825** ^Thus, the backup may be performed on a live source database without 6826** preventing other database connections from 6827** reading or writing to the source database while the backup is underway. 6828** 6829** ^(To perform a backup operation: 6830** <ol> 6831** <li><b>sqlite3_backup_init()</b> is called once to initialize the 6832** backup, 6833** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 6834** the data between the two databases, and finally 6835** <li><b>sqlite3_backup_finish()</b> is called to release all resources 6836** associated with the backup operation. 6837** </ol>)^ 6838** There should be exactly one call to sqlite3_backup_finish() for each 6839** successful call to sqlite3_backup_init(). 6840** 6841** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 6842** 6843** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 6844** [database connection] associated with the destination database 6845** and the database name, respectively. 6846** ^The database name is "main" for the main database, "temp" for the 6847** temporary database, or the name specified after the AS keyword in 6848** an [ATTACH] statement for an attached database. 6849** ^The S and M arguments passed to 6850** sqlite3_backup_init(D,N,S,M) identify the [database connection] 6851** and database name of the source database, respectively. 6852** ^The source and destination [database connections] (parameters S and D) 6853** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 6854** an error. 6855** 6856** ^A call to sqlite3_backup_init() will fail, returning SQLITE_ERROR, if 6857** there is already a read or read-write transaction open on the 6858** destination database. 6859** 6860** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 6861** returned and an error code and error message are stored in the 6862** destination [database connection] D. 6863** ^The error code and message for the failed call to sqlite3_backup_init() 6864** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 6865** [sqlite3_errmsg16()] functions. 6866** ^A successful call to sqlite3_backup_init() returns a pointer to an 6867** [sqlite3_backup] object. 6868** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 6869** sqlite3_backup_finish() functions to perform the specified backup 6870** operation. 6871** 6872** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 6873** 6874** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 6875** the source and destination databases specified by [sqlite3_backup] object B. 6876** ^If N is negative, all remaining source pages are copied. 6877** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 6878** are still more pages to be copied, then the function returns [SQLITE_OK]. 6879** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 6880** from source to destination, then it returns [SQLITE_DONE]. 6881** ^If an error occurs while running sqlite3_backup_step(B,N), 6882** then an [error code] is returned. ^As well as [SQLITE_OK] and 6883** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 6884** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 6885** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 6886** 6887** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 6888** <ol> 6889** <li> the destination database was opened read-only, or 6890** <li> the destination database is using write-ahead-log journaling 6891** and the destination and source page sizes differ, or 6892** <li> the destination database is an in-memory database and the 6893** destination and source page sizes differ. 6894** </ol>)^ 6895** 6896** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 6897** the [sqlite3_busy_handler | busy-handler function] 6898** is invoked (if one is specified). ^If the 6899** busy-handler returns non-zero before the lock is available, then 6900** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 6901** sqlite3_backup_step() can be retried later. ^If the source 6902** [database connection] 6903** is being used to write to the source database when sqlite3_backup_step() 6904** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 6905** case the call to sqlite3_backup_step() can be retried later on. ^(If 6906** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 6907** [SQLITE_READONLY] is returned, then 6908** there is no point in retrying the call to sqlite3_backup_step(). These 6909** errors are considered fatal.)^ The application must accept 6910** that the backup operation has failed and pass the backup operation handle 6911** to the sqlite3_backup_finish() to release associated resources. 6912** 6913** ^The first call to sqlite3_backup_step() obtains an exclusive lock 6914** on the destination file. ^The exclusive lock is not released until either 6915** sqlite3_backup_finish() is called or the backup operation is complete 6916** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 6917** sqlite3_backup_step() obtains a [shared lock] on the source database that 6918** lasts for the duration of the sqlite3_backup_step() call. 6919** ^Because the source database is not locked between calls to 6920** sqlite3_backup_step(), the source database may be modified mid-way 6921** through the backup process. ^If the source database is modified by an 6922** external process or via a database connection other than the one being 6923** used by the backup operation, then the backup will be automatically 6924** restarted by the next call to sqlite3_backup_step(). ^If the source 6925** database is modified by the using the same database connection as is used 6926** by the backup operation, then the backup database is automatically 6927** updated at the same time. 6928** 6929** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 6930** 6931** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 6932** application wishes to abandon the backup operation, the application 6933** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 6934** ^The sqlite3_backup_finish() interfaces releases all 6935** resources associated with the [sqlite3_backup] object. 6936** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 6937** active write-transaction on the destination database is rolled back. 6938** The [sqlite3_backup] object is invalid 6939** and may not be used following a call to sqlite3_backup_finish(). 6940** 6941** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 6942** sqlite3_backup_step() errors occurred, regardless or whether or not 6943** sqlite3_backup_step() completed. 6944** ^If an out-of-memory condition or IO error occurred during any prior 6945** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 6946** sqlite3_backup_finish() returns the corresponding [error code]. 6947** 6948** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 6949** is not a permanent error and does not affect the return value of 6950** sqlite3_backup_finish(). 6951** 6952** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]] 6953** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 6954** 6955** ^Each call to sqlite3_backup_step() sets two values inside 6956** the [sqlite3_backup] object: the number of pages still to be backed 6957** up and the total number of pages in the source database file. 6958** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 6959** retrieve these two values, respectively. 6960** 6961** ^The values returned by these functions are only updated by 6962** sqlite3_backup_step(). ^If the source database is modified during a backup 6963** operation, then the values are not updated to account for any extra 6964** pages that need to be updated or the size of the source database file 6965** changing. 6966** 6967** <b>Concurrent Usage of Database Handles</b> 6968** 6969** ^The source [database connection] may be used by the application for other 6970** purposes while a backup operation is underway or being initialized. 6971** ^If SQLite is compiled and configured to support threadsafe database 6972** connections, then the source database connection may be used concurrently 6973** from within other threads. 6974** 6975** However, the application must guarantee that the destination 6976** [database connection] is not passed to any other API (by any thread) after 6977** sqlite3_backup_init() is called and before the corresponding call to 6978** sqlite3_backup_finish(). SQLite does not currently check to see 6979** if the application incorrectly accesses the destination [database connection] 6980** and so no error code is reported, but the operations may malfunction 6981** nevertheless. Use of the destination database connection while a 6982** backup is in progress might also also cause a mutex deadlock. 6983** 6984** If running in [shared cache mode], the application must 6985** guarantee that the shared cache used by the destination database 6986** is not accessed while the backup is running. In practice this means 6987** that the application must guarantee that the disk file being 6988** backed up to is not accessed by any connection within the process, 6989** not just the specific connection that was passed to sqlite3_backup_init(). 6990** 6991** The [sqlite3_backup] object itself is partially threadsafe. Multiple 6992** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 6993** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 6994** APIs are not strictly speaking threadsafe. If they are invoked at the 6995** same time as another thread is invoking sqlite3_backup_step() it is 6996** possible that they return invalid values. 6997*/ 6998sqlite3_backup *sqlite3_backup_init( 6999 sqlite3 *pDest, /* Destination database handle */ 7000 const char *zDestName, /* Destination database name */ 7001 sqlite3 *pSource, /* Source database handle */ 7002 const char *zSourceName /* Source database name */ 7003); 7004int sqlite3_backup_step(sqlite3_backup *p, int nPage); 7005int sqlite3_backup_finish(sqlite3_backup *p); 7006int sqlite3_backup_remaining(sqlite3_backup *p); 7007int sqlite3_backup_pagecount(sqlite3_backup *p); 7008 7009/* 7010** CAPI3REF: Unlock Notification 7011** 7012** ^When running in shared-cache mode, a database operation may fail with 7013** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7014** individual tables within the shared-cache cannot be obtained. See 7015** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7016** ^This API may be used to register a callback that SQLite will invoke 7017** when the connection currently holding the required lock relinquishes it. 7018** ^This API is only available if the library was compiled with the 7019** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7020** 7021** See Also: [Using the SQLite Unlock Notification Feature]. 7022** 7023** ^Shared-cache locks are released when a database connection concludes 7024** its current transaction, either by committing it or rolling it back. 7025** 7026** ^When a connection (known as the blocked connection) fails to obtain a 7027** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7028** identity of the database connection (the blocking connection) that 7029** has locked the required resource is stored internally. ^After an 7030** application receives an SQLITE_LOCKED error, it may call the 7031** sqlite3_unlock_notify() method with the blocked connection handle as 7032** the first argument to register for a callback that will be invoked 7033** when the blocking connections current transaction is concluded. ^The 7034** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7035** call that concludes the blocking connections transaction. 7036** 7037** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7038** there is a chance that the blocking connection will have already 7039** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7040** If this happens, then the specified callback is invoked immediately, 7041** from within the call to sqlite3_unlock_notify().)^ 7042** 7043** ^If the blocked connection is attempting to obtain a write-lock on a 7044** shared-cache table, and more than one other connection currently holds 7045** a read-lock on the same table, then SQLite arbitrarily selects one of 7046** the other connections to use as the blocking connection. 7047** 7048** ^(There may be at most one unlock-notify callback registered by a 7049** blocked connection. If sqlite3_unlock_notify() is called when the 7050** blocked connection already has a registered unlock-notify callback, 7051** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7052** called with a NULL pointer as its second argument, then any existing 7053** unlock-notify callback is canceled. ^The blocked connections 7054** unlock-notify callback may also be canceled by closing the blocked 7055** connection using [sqlite3_close()]. 7056** 7057** The unlock-notify callback is not reentrant. If an application invokes 7058** any sqlite3_xxx API functions from within an unlock-notify callback, a 7059** crash or deadlock may be the result. 7060** 7061** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7062** returns SQLITE_OK. 7063** 7064** <b>Callback Invocation Details</b> 7065** 7066** When an unlock-notify callback is registered, the application provides a 7067** single void* pointer that is passed to the callback when it is invoked. 7068** However, the signature of the callback function allows SQLite to pass 7069** it an array of void* context pointers. The first argument passed to 7070** an unlock-notify callback is a pointer to an array of void* pointers, 7071** and the second is the number of entries in the array. 7072** 7073** When a blocking connections transaction is concluded, there may be 7074** more than one blocked connection that has registered for an unlock-notify 7075** callback. ^If two or more such blocked connections have specified the 7076** same callback function, then instead of invoking the callback function 7077** multiple times, it is invoked once with the set of void* context pointers 7078** specified by the blocked connections bundled together into an array. 7079** This gives the application an opportunity to prioritize any actions 7080** related to the set of unblocked database connections. 7081** 7082** <b>Deadlock Detection</b> 7083** 7084** Assuming that after registering for an unlock-notify callback a 7085** database waits for the callback to be issued before taking any further 7086** action (a reasonable assumption), then using this API may cause the 7087** application to deadlock. For example, if connection X is waiting for 7088** connection Y's transaction to be concluded, and similarly connection 7089** Y is waiting on connection X's transaction, then neither connection 7090** will proceed and the system may remain deadlocked indefinitely. 7091** 7092** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7093** detection. ^If a given call to sqlite3_unlock_notify() would put the 7094** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7095** unlock-notify callback is registered. The system is said to be in 7096** a deadlocked state if connection A has registered for an unlock-notify 7097** callback on the conclusion of connection B's transaction, and connection 7098** B has itself registered for an unlock-notify callback when connection 7099** A's transaction is concluded. ^Indirect deadlock is also detected, so 7100** the system is also considered to be deadlocked if connection B has 7101** registered for an unlock-notify callback on the conclusion of connection 7102** C's transaction, where connection C is waiting on connection A. ^Any 7103** number of levels of indirection are allowed. 7104** 7105** <b>The "DROP TABLE" Exception</b> 7106** 7107** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7108** always appropriate to call sqlite3_unlock_notify(). There is however, 7109** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7110** SQLite checks if there are any currently executing SELECT statements 7111** that belong to the same connection. If there are, SQLITE_LOCKED is 7112** returned. In this case there is no "blocking connection", so invoking 7113** sqlite3_unlock_notify() results in the unlock-notify callback being 7114** invoked immediately. If the application then re-attempts the "DROP TABLE" 7115** or "DROP INDEX" query, an infinite loop might be the result. 7116** 7117** One way around this problem is to check the extended error code returned 7118** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7119** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7120** the special "DROP TABLE/INDEX" case, the extended error code is just 7121** SQLITE_LOCKED.)^ 7122*/ 7123int sqlite3_unlock_notify( 7124 sqlite3 *pBlocked, /* Waiting connection */ 7125 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7126 void *pNotifyArg /* Argument to pass to xNotify */ 7127); 7128 7129 7130/* 7131** CAPI3REF: String Comparison 7132** 7133** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7134** and extensions to compare the contents of two buffers containing UTF-8 7135** strings in a case-independent fashion, using the same definition of "case 7136** independence" that SQLite uses internally when comparing identifiers. 7137*/ 7138int sqlite3_stricmp(const char *, const char *); 7139int sqlite3_strnicmp(const char *, const char *, int); 7140 7141/* 7142** CAPI3REF: String Globbing 7143* 7144** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches 7145** the glob pattern P, and it returns non-zero if string X does not match 7146** the glob pattern P. ^The definition of glob pattern matching used in 7147** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7148** SQL dialect used by SQLite. ^The sqlite3_strglob(P,X) function is case 7149** sensitive. 7150** 7151** Note that this routine returns zero on a match and non-zero if the strings 7152** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7153*/ 7154int sqlite3_strglob(const char *zGlob, const char *zStr); 7155 7156/* 7157** CAPI3REF: Error Logging Interface 7158** 7159** ^The [sqlite3_log()] interface writes a message into the [error log] 7160** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7161** ^If logging is enabled, the zFormat string and subsequent arguments are 7162** used with [sqlite3_snprintf()] to generate the final output string. 7163** 7164** The sqlite3_log() interface is intended for use by extensions such as 7165** virtual tables, collating functions, and SQL functions. While there is 7166** nothing to prevent an application from calling sqlite3_log(), doing so 7167** is considered bad form. 7168** 7169** The zFormat string must not be NULL. 7170** 7171** To avoid deadlocks and other threading problems, the sqlite3_log() routine 7172** will not use dynamically allocated memory. The log message is stored in 7173** a fixed-length buffer on the stack. If the log message is longer than 7174** a few hundred characters, it will be truncated to the length of the 7175** buffer. 7176*/ 7177void sqlite3_log(int iErrCode, const char *zFormat, ...); 7178 7179/* 7180** CAPI3REF: Write-Ahead Log Commit Hook 7181** 7182** ^The [sqlite3_wal_hook()] function is used to register a callback that 7183** is invoked each time data is committed to a database in wal mode. 7184** 7185** ^(The callback is invoked by SQLite after the commit has taken place and 7186** the associated write-lock on the database released)^, so the implementation 7187** may read, write or [checkpoint] the database as required. 7188** 7189** ^The first parameter passed to the callback function when it is invoked 7190** is a copy of the third parameter passed to sqlite3_wal_hook() when 7191** registering the callback. ^The second is a copy of the database handle. 7192** ^The third parameter is the name of the database that was written to - 7193** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 7194** is the number of pages currently in the write-ahead log file, 7195** including those that were just committed. 7196** 7197** The callback function should normally return [SQLITE_OK]. ^If an error 7198** code is returned, that error will propagate back up through the 7199** SQLite code base to cause the statement that provoked the callback 7200** to report an error, though the commit will have still occurred. If the 7201** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 7202** that does not correspond to any valid SQLite error code, the results 7203** are undefined. 7204** 7205** A single database handle may have at most a single write-ahead log callback 7206** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 7207** previously registered write-ahead log callback. ^Note that the 7208** [sqlite3_wal_autocheckpoint()] interface and the 7209** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 7210** those overwrite any prior [sqlite3_wal_hook()] settings. 7211*/ 7212void *sqlite3_wal_hook( 7213 sqlite3*, 7214 int(*)(void *,sqlite3*,const char*,int), 7215 void* 7216); 7217 7218/* 7219** CAPI3REF: Configure an auto-checkpoint 7220** 7221** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 7222** [sqlite3_wal_hook()] that causes any database on [database connection] D 7223** to automatically [checkpoint] 7224** after committing a transaction if there are N or 7225** more frames in the [write-ahead log] file. ^Passing zero or 7226** a negative value as the nFrame parameter disables automatic 7227** checkpoints entirely. 7228** 7229** ^The callback registered by this function replaces any existing callback 7230** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 7231** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 7232** configured by this function. 7233** 7234** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 7235** from SQL. 7236** 7237** ^Checkpoints initiated by this mechanism are 7238** [sqlite3_wal_checkpoint_v2|PASSIVE]. 7239** 7240** ^Every new [database connection] defaults to having the auto-checkpoint 7241** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 7242** pages. The use of this interface 7243** is only necessary if the default setting is found to be suboptimal 7244** for a particular application. 7245*/ 7246int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 7247 7248/* 7249** CAPI3REF: Checkpoint a database 7250** 7251** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 7252** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 7253** 7254** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 7255** [write-ahead log] for database X on [database connection] D to be 7256** transferred into the database file and for the write-ahead log to 7257** be reset. See the [checkpointing] documentation for addition 7258** information. 7259** 7260** This interface used to be the only way to cause a checkpoint to 7261** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 7262** interface was added. This interface is retained for backwards 7263** compatibility and as a convenience for applications that need to manually 7264** start a callback but which do not need the full power (and corresponding 7265** complication) of [sqlite3_wal_checkpoint_v2()]. 7266*/ 7267int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 7268 7269/* 7270** CAPI3REF: Checkpoint a database 7271** 7272** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 7273** operation on database X of [database connection] D in mode M. Status 7274** information is written back into integers pointed to by L and C.)^ 7275** ^(The M parameter must be a valid [checkpoint mode]:)^ 7276** 7277** <dl> 7278** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 7279** ^Checkpoint as many frames as possible without waiting for any database 7280** readers or writers to finish, then sync the database file if all frames 7281** in the log were checkpointed. ^The [busy-handler callback] 7282** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 7283** ^On the other hand, passive mode might leave the checkpoint unfinished 7284** if there are concurrent readers or writers. 7285** 7286** <dt>SQLITE_CHECKPOINT_FULL<dd> 7287** ^This mode blocks (it invokes the 7288** [sqlite3_busy_handler|busy-handler callback]) until there is no 7289** database writer and all readers are reading from the most recent database 7290** snapshot. ^It then checkpoints all frames in the log file and syncs the 7291** database file. ^This mode blocks new database writers while it is pending, 7292** but new database readers are allowed to continue unimpeded. 7293** 7294** <dt>SQLITE_CHECKPOINT_RESTART<dd> 7295** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 7296** that after checkpointing the log file it blocks (calls the 7297** [busy-handler callback]) 7298** until all readers are reading from the database file only. ^This ensures 7299** that the next writer will restart the log file from the beginning. 7300** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 7301** database writer attempts while it is pending, but does not impede readers. 7302** 7303** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 7304** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 7305** addition that it also truncates the log file to zero bytes just prior 7306** to a successful return. 7307** </dl> 7308** 7309** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 7310** the log file or to -1 if the checkpoint could not run because 7311** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 7312** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 7313** log file (including any that were already checkpointed before the function 7314** was called) or to -1 if the checkpoint could not run due to an error or 7315** because the database is not in WAL mode. ^Note that upon successful 7316** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 7317** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 7318** 7319** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 7320** any other process is running a checkpoint operation at the same time, the 7321** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 7322** busy-handler configured, it will not be invoked in this case. 7323** 7324** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 7325** exclusive "writer" lock on the database file. ^If the writer lock cannot be 7326** obtained immediately, and a busy-handler is configured, it is invoked and 7327** the writer lock retried until either the busy-handler returns 0 or the lock 7328** is successfully obtained. ^The busy-handler is also invoked while waiting for 7329** database readers as described above. ^If the busy-handler returns 0 before 7330** the writer lock is obtained or while waiting for database readers, the 7331** checkpoint operation proceeds from that point in the same way as 7332** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 7333** without blocking any further. ^SQLITE_BUSY is returned in this case. 7334** 7335** ^If parameter zDb is NULL or points to a zero length string, then the 7336** specified operation is attempted on all WAL databases [attached] to 7337** [database connection] db. In this case the 7338** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 7339** an SQLITE_BUSY error is encountered when processing one or more of the 7340** attached WAL databases, the operation is still attempted on any remaining 7341** attached databases and SQLITE_BUSY is returned at the end. ^If any other 7342** error occurs while processing an attached database, processing is abandoned 7343** and the error code is returned to the caller immediately. ^If no error 7344** (SQLITE_BUSY or otherwise) is encountered while processing the attached 7345** databases, SQLITE_OK is returned. 7346** 7347** ^If database zDb is the name of an attached database that is not in WAL 7348** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 7349** zDb is not NULL (or a zero length string) and is not the name of any 7350** attached database, SQLITE_ERROR is returned to the caller. 7351** 7352** ^Unless it returns SQLITE_MISUSE, 7353** the sqlite3_wal_checkpoint_v2() interface 7354** sets the error information that is queried by 7355** [sqlite3_errcode()] and [sqlite3_errmsg()]. 7356** 7357** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 7358** from SQL. 7359*/ 7360int sqlite3_wal_checkpoint_v2( 7361 sqlite3 *db, /* Database handle */ 7362 const char *zDb, /* Name of attached database (or NULL) */ 7363 int eMode, /* SQLITE_CHECKPOINT_* value */ 7364 int *pnLog, /* OUT: Size of WAL log in frames */ 7365 int *pnCkpt /* OUT: Total number of frames checkpointed */ 7366); 7367 7368/* 7369** CAPI3REF: Checkpoint Mode Values 7370** KEYWORDS: {checkpoint mode} 7371** 7372** These constants define all valid values for the "checkpoint mode" passed 7373** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 7374** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 7375** meaning of each of these checkpoint modes. 7376*/ 7377#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 7378#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 7379#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 7380#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 7381 7382/* 7383** CAPI3REF: Virtual Table Interface Configuration 7384** 7385** This function may be called by either the [xConnect] or [xCreate] method 7386** of a [virtual table] implementation to configure 7387** various facets of the virtual table interface. 7388** 7389** If this interface is invoked outside the context of an xConnect or 7390** xCreate virtual table method then the behavior is undefined. 7391** 7392** At present, there is only one option that may be configured using 7393** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 7394** may be added in the future. 7395*/ 7396int sqlite3_vtab_config(sqlite3*, int op, ...); 7397 7398/* 7399** CAPI3REF: Virtual Table Configuration Options 7400** 7401** These macros define the various options to the 7402** [sqlite3_vtab_config()] interface that [virtual table] implementations 7403** can use to customize and optimize their behavior. 7404** 7405** <dl> 7406** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 7407** <dd>Calls of the form 7408** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 7409** where X is an integer. If X is zero, then the [virtual table] whose 7410** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 7411** support constraints. In this configuration (which is the default) if 7412** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 7413** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 7414** specified as part of the users SQL statement, regardless of the actual 7415** ON CONFLICT mode specified. 7416** 7417** If X is non-zero, then the virtual table implementation guarantees 7418** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 7419** any modifications to internal or persistent data structures have been made. 7420** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 7421** is able to roll back a statement or database transaction, and abandon 7422** or continue processing the current SQL statement as appropriate. 7423** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 7424** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 7425** had been ABORT. 7426** 7427** Virtual table implementations that are required to handle OR REPLACE 7428** must do so within the [xUpdate] method. If a call to the 7429** [sqlite3_vtab_on_conflict()] function indicates that the current ON 7430** CONFLICT policy is REPLACE, the virtual table implementation should 7431** silently replace the appropriate rows within the xUpdate callback and 7432** return SQLITE_OK. Or, if this is not possible, it may return 7433** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 7434** constraint handling. 7435** </dl> 7436*/ 7437#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 7438 7439/* 7440** CAPI3REF: Determine The Virtual Table Conflict Policy 7441** 7442** This function may only be called from within a call to the [xUpdate] method 7443** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 7444** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 7445** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 7446** of the SQL statement that triggered the call to the [xUpdate] method of the 7447** [virtual table]. 7448*/ 7449int sqlite3_vtab_on_conflict(sqlite3 *); 7450 7451/* 7452** CAPI3REF: Conflict resolution modes 7453** KEYWORDS: {conflict resolution mode} 7454** 7455** These constants are returned by [sqlite3_vtab_on_conflict()] to 7456** inform a [virtual table] implementation what the [ON CONFLICT] mode 7457** is for the SQL statement being evaluated. 7458** 7459** Note that the [SQLITE_IGNORE] constant is also used as a potential 7460** return value from the [sqlite3_set_authorizer()] callback and that 7461** [SQLITE_ABORT] is also a [result code]. 7462*/ 7463#define SQLITE_ROLLBACK 1 7464/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 7465#define SQLITE_FAIL 3 7466/* #define SQLITE_ABORT 4 // Also an error code */ 7467#define SQLITE_REPLACE 5 7468 7469/* 7470** CAPI3REF: Prepared Statement Scan Status Opcodes 7471** KEYWORDS: {scanstatus options} 7472** 7473** The following constants can be used for the T parameter to the 7474** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 7475** different metric for sqlite3_stmt_scanstatus() to return. 7476** 7477** <dl> 7478** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 7479** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 7480** set to the total number of times that the X-th loop has run.</dd> 7481** 7482** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 7483** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 7484** to the total number of rows examined by all iterations of the X-th loop.</dd> 7485** 7486** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 7487** <dd>^The "double" variable pointed to by the T parameter will be set to the 7488** query planner's estimate for the average number of rows output from each 7489** iteration of the X-th loop. If the query planner's estimates was accurate, 7490** then this value will approximate the quotient NVISIT/NLOOP and the 7491** product of this value for all prior loops with the same SELECTID will 7492** be the NLOOP value for the current loop. 7493** 7494** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 7495** <dd>^The "const char *" variable pointed to by the T parameter will be set 7496** to a zero-terminated UTF-8 string containing the name of the index or table 7497** used for the X-th loop. 7498** 7499** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 7500** <dd>^The "const char *" variable pointed to by the T parameter will be set 7501** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 7502** description for the X-th loop. 7503** 7504** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 7505** <dd>^The "int" variable pointed to by the T parameter will be set to the 7506** "select-id" for the X-th loop. The select-id identifies which query or 7507** subquery the loop is part of. The main query has a select-id of zero. 7508** The select-id is the same value as is output in the first column 7509** of an [EXPLAIN QUERY PLAN] query. 7510** </dl> 7511*/ 7512#define SQLITE_SCANSTAT_NLOOP 0 7513#define SQLITE_SCANSTAT_NVISIT 1 7514#define SQLITE_SCANSTAT_EST 2 7515#define SQLITE_SCANSTAT_NAME 3 7516#define SQLITE_SCANSTAT_EXPLAIN 4 7517#define SQLITE_SCANSTAT_SELECTID 5 7518 7519/* 7520** CAPI3REF: Prepared Statement Scan Status 7521** 7522** Return status data for a single loop within query pStmt. 7523** 7524** The "iScanStatusOp" parameter determines which status information to return. 7525** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 7526** of this interface is undefined. 7527** ^The requested measurement is written into a variable pointed to by 7528** the "pOut" parameter. 7529** Parameter "idx" identifies the specific loop to retrieve statistics for. 7530** Loops are numbered starting from zero. ^If idx is out of range - less than 7531** zero or greater than or equal to the total number of loops used to implement 7532** the statement - a non-zero value is returned and the variable that pOut 7533** points to is unchanged. 7534** 7535** ^Statistics might not be available for all loops in all statements. ^In cases 7536** where there exist loops with no available statistics, this function behaves 7537** as if the loop did not exist - it returns non-zero and leave the variable 7538** that pOut points to unchanged. 7539** 7540** This API is only available if the library is built with pre-processor 7541** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 7542** 7543** See also: [sqlite3_stmt_scanstatus_reset()] 7544*/ 7545SQLITE_EXPERIMENTAL int sqlite3_stmt_scanstatus( 7546 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 7547 int idx, /* Index of loop to report on */ 7548 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 7549 void *pOut /* Result written here */ 7550); 7551 7552/* 7553** CAPI3REF: Zero Scan-Status Counters 7554** 7555** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 7556** 7557** This API is only available if the library is built with pre-processor 7558** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 7559*/ 7560SQLITE_EXPERIMENTAL void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 7561 7562 7563/* 7564** Undo the hack that converts floating point types to integer for 7565** builds on processors without floating point support. 7566*/ 7567#ifdef SQLITE_OMIT_FLOATING_POINT 7568# undef double 7569#endif 7570 7571#ifdef __cplusplus 7572} /* End of the 'extern "C"' block */ 7573#endif 7574#endif /* _SQLITE3_H_ */ 7575