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** 1749** [[SQLITE_CONFIG_PMASZ]] 1750** <dt>SQLITE_CONFIG_PMASZ 1751** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1752** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1753** sorter to that integer. The default minimum PMA Size is set by the 1754** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1755** to help with sort operations when multithreaded sorting 1756** is enabled (using the [PRAGMA threads] command) and the amount of content 1757** to be sorted exceeds the page size times the minimum of the 1758** [PRAGMA cache_size] setting and this value. 1759** </dl> 1760*/ 1761#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1762#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1763#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1764#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1765#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1766#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1767#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1768#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1769#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1770#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1771#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1772/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1773#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1774#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1775#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1776#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1777#define SQLITE_CONFIG_URI 17 /* int */ 1778#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1779#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1780#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1781#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1782#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1783#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1784#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1785#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 1786 1787/* 1788** CAPI3REF: Database Connection Configuration Options 1789** 1790** These constants are the available integer configuration options that 1791** can be passed as the second argument to the [sqlite3_db_config()] interface. 1792** 1793** New configuration options may be added in future releases of SQLite. 1794** Existing configuration options might be discontinued. Applications 1795** should check the return code from [sqlite3_db_config()] to make sure that 1796** the call worked. ^The [sqlite3_db_config()] interface will return a 1797** non-zero [error code] if a discontinued or unsupported configuration option 1798** is invoked. 1799** 1800** <dl> 1801** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1802** <dd> ^This option takes three additional arguments that determine the 1803** [lookaside memory allocator] configuration for the [database connection]. 1804** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1805** pointer to a memory buffer to use for lookaside memory. 1806** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1807** may be NULL in which case SQLite will allocate the 1808** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1809** size of each lookaside buffer slot. ^The third argument is the number of 1810** slots. The size of the buffer in the first argument must be greater than 1811** or equal to the product of the second and third arguments. The buffer 1812** must be aligned to an 8-byte boundary. ^If the second argument to 1813** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1814** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1815** configuration for a database connection can only be changed when that 1816** connection is not currently using lookaside memory, or in other words 1817** when the "current value" returned by 1818** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1819** Any attempt to change the lookaside memory configuration when lookaside 1820** memory is in use leaves the configuration unchanged and returns 1821** [SQLITE_BUSY].)^</dd> 1822** 1823** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1824** <dd> ^This option is used to enable or disable the enforcement of 1825** [foreign key constraints]. There should be two additional arguments. 1826** The first argument is an integer which is 0 to disable FK enforcement, 1827** positive to enable FK enforcement or negative to leave FK enforcement 1828** unchanged. The second parameter is a pointer to an integer into which 1829** is written 0 or 1 to indicate whether FK enforcement is off or on 1830** following this call. The second parameter may be a NULL pointer, in 1831** which case the FK enforcement setting is not reported back. </dd> 1832** 1833** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1834** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1835** There should be two additional arguments. 1836** The first argument is an integer which is 0 to disable triggers, 1837** positive to enable triggers or negative to leave the setting unchanged. 1838** The second parameter is a pointer to an integer into which 1839** is written 0 or 1 to indicate whether triggers are disabled or enabled 1840** following this call. The second parameter may be a NULL pointer, in 1841** which case the trigger setting is not reported back. </dd> 1842** 1843** </dl> 1844*/ 1845#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1846#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1847#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1848 1849 1850/* 1851** CAPI3REF: Enable Or Disable Extended Result Codes 1852** 1853** ^The sqlite3_extended_result_codes() routine enables or disables the 1854** [extended result codes] feature of SQLite. ^The extended result 1855** codes are disabled by default for historical compatibility. 1856*/ 1857int sqlite3_extended_result_codes(sqlite3*, int onoff); 1858 1859/* 1860** CAPI3REF: Last Insert Rowid 1861** 1862** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 1863** has a unique 64-bit signed 1864** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1865** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1866** names are not also used by explicitly declared columns. ^If 1867** the table has a column of type [INTEGER PRIMARY KEY] then that column 1868** is another alias for the rowid. 1869** 1870** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the 1871** most recent successful [INSERT] into a rowid table or [virtual table] 1872** on database connection D. 1873** ^Inserts into [WITHOUT ROWID] tables are not recorded. 1874** ^If no successful [INSERT]s into rowid tables 1875** have ever occurred on the database connection D, 1876** then sqlite3_last_insert_rowid(D) returns zero. 1877** 1878** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1879** method, then this routine will return the [rowid] of the inserted 1880** row as long as the trigger or virtual table method is running. 1881** But once the trigger or virtual table method ends, the value returned 1882** by this routine reverts to what it was before the trigger or virtual 1883** table method began.)^ 1884** 1885** ^An [INSERT] that fails due to a constraint violation is not a 1886** successful [INSERT] and does not change the value returned by this 1887** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1888** and INSERT OR ABORT make no changes to the return value of this 1889** routine when their insertion fails. ^(When INSERT OR REPLACE 1890** encounters a constraint violation, it does not fail. The 1891** INSERT continues to completion after deleting rows that caused 1892** the constraint problem so INSERT OR REPLACE will always change 1893** the return value of this interface.)^ 1894** 1895** ^For the purposes of this routine, an [INSERT] is considered to 1896** be successful even if it is subsequently rolled back. 1897** 1898** This function is accessible to SQL statements via the 1899** [last_insert_rowid() SQL function]. 1900** 1901** If a separate thread performs a new [INSERT] on the same 1902** database connection while the [sqlite3_last_insert_rowid()] 1903** function is running and thus changes the last insert [rowid], 1904** then the value returned by [sqlite3_last_insert_rowid()] is 1905** unpredictable and might not equal either the old or the new 1906** last insert [rowid]. 1907*/ 1908sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1909 1910/* 1911** CAPI3REF: Count The Number Of Rows Modified 1912** 1913** ^This function returns the number of rows modified, inserted or 1914** deleted by the most recently completed INSERT, UPDATE or DELETE 1915** statement on the database connection specified by the only parameter. 1916** ^Executing any other type of SQL statement does not modify the value 1917** returned by this function. 1918** 1919** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 1920** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 1921** [foreign key actions] or [REPLACE] constraint resolution are not counted. 1922** 1923** Changes to a view that are intercepted by 1924** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 1925** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 1926** DELETE statement run on a view is always zero. Only changes made to real 1927** tables are counted. 1928** 1929** Things are more complicated if the sqlite3_changes() function is 1930** executed while a trigger program is running. This may happen if the 1931** program uses the [changes() SQL function], or if some other callback 1932** function invokes sqlite3_changes() directly. Essentially: 1933** 1934** <ul> 1935** <li> ^(Before entering a trigger program the value returned by 1936** sqlite3_changes() function is saved. After the trigger program 1937** has finished, the original value is restored.)^ 1938** 1939** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 1940** statement sets the value returned by sqlite3_changes() 1941** upon completion as normal. Of course, this value will not include 1942** any changes performed by sub-triggers, as the sqlite3_changes() 1943** value will be saved and restored after each sub-trigger has run.)^ 1944** </ul> 1945** 1946** ^This means that if the changes() SQL function (or similar) is used 1947** by the first INSERT, UPDATE or DELETE statement within a trigger, it 1948** returns the value as set when the calling statement began executing. 1949** ^If it is used by the second or subsequent such statement within a trigger 1950** program, the value returned reflects the number of rows modified by the 1951** previous INSERT, UPDATE or DELETE statement within the same trigger. 1952** 1953** See also the [sqlite3_total_changes()] interface, the 1954** [count_changes pragma], and the [changes() SQL function]. 1955** 1956** If a separate thread makes changes on the same database connection 1957** while [sqlite3_changes()] is running then the value returned 1958** is unpredictable and not meaningful. 1959*/ 1960int sqlite3_changes(sqlite3*); 1961 1962/* 1963** CAPI3REF: Total Number Of Rows Modified 1964** 1965** ^This function returns the total number of rows inserted, modified or 1966** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 1967** since the database connection was opened, including those executed as 1968** part of trigger programs. ^Executing any other type of SQL statement 1969** does not affect the value returned by sqlite3_total_changes(). 1970** 1971** ^Changes made as part of [foreign key actions] are included in the 1972** count, but those made as part of REPLACE constraint resolution are 1973** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 1974** are not counted. 1975** 1976** See also the [sqlite3_changes()] interface, the 1977** [count_changes pragma], and the [total_changes() SQL function]. 1978** 1979** If a separate thread makes changes on the same database connection 1980** while [sqlite3_total_changes()] is running then the value 1981** returned is unpredictable and not meaningful. 1982*/ 1983int sqlite3_total_changes(sqlite3*); 1984 1985/* 1986** CAPI3REF: Interrupt A Long-Running Query 1987** 1988** ^This function causes any pending database operation to abort and 1989** return at its earliest opportunity. This routine is typically 1990** called in response to a user action such as pressing "Cancel" 1991** or Ctrl-C where the user wants a long query operation to halt 1992** immediately. 1993** 1994** ^It is safe to call this routine from a thread different from the 1995** thread that is currently running the database operation. But it 1996** is not safe to call this routine with a [database connection] that 1997** is closed or might close before sqlite3_interrupt() returns. 1998** 1999** ^If an SQL operation is very nearly finished at the time when 2000** sqlite3_interrupt() is called, then it might not have an opportunity 2001** to be interrupted and might continue to completion. 2002** 2003** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2004** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2005** that is inside an explicit transaction, then the entire transaction 2006** will be rolled back automatically. 2007** 2008** ^The sqlite3_interrupt(D) call is in effect until all currently running 2009** SQL statements on [database connection] D complete. ^Any new SQL statements 2010** that are started after the sqlite3_interrupt() call and before the 2011** running statements reaches zero are interrupted as if they had been 2012** running prior to the sqlite3_interrupt() call. ^New SQL statements 2013** that are started after the running statement count reaches zero are 2014** not effected by the sqlite3_interrupt(). 2015** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2016** SQL statements is a no-op and has no effect on SQL statements 2017** that are started after the sqlite3_interrupt() call returns. 2018** 2019** If the database connection closes while [sqlite3_interrupt()] 2020** is running then bad things will likely happen. 2021*/ 2022void sqlite3_interrupt(sqlite3*); 2023 2024/* 2025** CAPI3REF: Determine If An SQL Statement Is Complete 2026** 2027** These routines are useful during command-line input to determine if the 2028** currently entered text seems to form a complete SQL statement or 2029** if additional input is needed before sending the text into 2030** SQLite for parsing. ^These routines return 1 if the input string 2031** appears to be a complete SQL statement. ^A statement is judged to be 2032** complete if it ends with a semicolon token and is not a prefix of a 2033** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2034** string literals or quoted identifier names or comments are not 2035** independent tokens (they are part of the token in which they are 2036** embedded) and thus do not count as a statement terminator. ^Whitespace 2037** and comments that follow the final semicolon are ignored. 2038** 2039** ^These routines return 0 if the statement is incomplete. ^If a 2040** memory allocation fails, then SQLITE_NOMEM is returned. 2041** 2042** ^These routines do not parse the SQL statements thus 2043** will not detect syntactically incorrect SQL. 2044** 2045** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2046** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2047** automatically by sqlite3_complete16(). If that initialization fails, 2048** then the return value from sqlite3_complete16() will be non-zero 2049** regardless of whether or not the input SQL is complete.)^ 2050** 2051** The input to [sqlite3_complete()] must be a zero-terminated 2052** UTF-8 string. 2053** 2054** The input to [sqlite3_complete16()] must be a zero-terminated 2055** UTF-16 string in native byte order. 2056*/ 2057int sqlite3_complete(const char *sql); 2058int sqlite3_complete16(const void *sql); 2059 2060/* 2061** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2062** KEYWORDS: {busy-handler callback} {busy handler} 2063** 2064** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2065** that might be invoked with argument P whenever 2066** an attempt is made to access a database table associated with 2067** [database connection] D when another thread 2068** or process has the table locked. 2069** The sqlite3_busy_handler() interface is used to implement 2070** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2071** 2072** ^If the busy callback is NULL, then [SQLITE_BUSY] 2073** is returned immediately upon encountering the lock. ^If the busy callback 2074** is not NULL, then the callback might be invoked with two arguments. 2075** 2076** ^The first argument to the busy handler is a copy of the void* pointer which 2077** is the third argument to sqlite3_busy_handler(). ^The second argument to 2078** the busy handler callback is the number of times that the busy handler has 2079** been invoked previously for the same locking event. ^If the 2080** busy callback returns 0, then no additional attempts are made to 2081** access the database and [SQLITE_BUSY] is returned 2082** to the application. 2083** ^If the callback returns non-zero, then another attempt 2084** is made to access the database and the cycle repeats. 2085** 2086** The presence of a busy handler does not guarantee that it will be invoked 2087** when there is lock contention. ^If SQLite determines that invoking the busy 2088** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2089** to the application instead of invoking the 2090** busy handler. 2091** Consider a scenario where one process is holding a read lock that 2092** it is trying to promote to a reserved lock and 2093** a second process is holding a reserved lock that it is trying 2094** to promote to an exclusive lock. The first process cannot proceed 2095** because it is blocked by the second and the second process cannot 2096** proceed because it is blocked by the first. If both processes 2097** invoke the busy handlers, neither will make any progress. Therefore, 2098** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2099** will induce the first process to release its read lock and allow 2100** the second process to proceed. 2101** 2102** ^The default busy callback is NULL. 2103** 2104** ^(There can only be a single busy handler defined for each 2105** [database connection]. Setting a new busy handler clears any 2106** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2107** or evaluating [PRAGMA busy_timeout=N] will change the 2108** busy handler and thus clear any previously set busy handler. 2109** 2110** The busy callback should not take any actions which modify the 2111** database connection that invoked the busy handler. In other words, 2112** the busy handler is not reentrant. Any such actions 2113** result in undefined behavior. 2114** 2115** A busy handler must not close the database connection 2116** or [prepared statement] that invoked the busy handler. 2117*/ 2118int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 2119 2120/* 2121** CAPI3REF: Set A Busy Timeout 2122** 2123** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2124** for a specified amount of time when a table is locked. ^The handler 2125** will sleep multiple times until at least "ms" milliseconds of sleeping 2126** have accumulated. ^After at least "ms" milliseconds of sleeping, 2127** the handler returns 0 which causes [sqlite3_step()] to return 2128** [SQLITE_BUSY]. 2129** 2130** ^Calling this routine with an argument less than or equal to zero 2131** turns off all busy handlers. 2132** 2133** ^(There can only be a single busy handler for a particular 2134** [database connection] at any given moment. If another busy handler 2135** was defined (using [sqlite3_busy_handler()]) prior to calling 2136** this routine, that other busy handler is cleared.)^ 2137** 2138** See also: [PRAGMA busy_timeout] 2139*/ 2140int sqlite3_busy_timeout(sqlite3*, int ms); 2141 2142/* 2143** CAPI3REF: Convenience Routines For Running Queries 2144** 2145** This is a legacy interface that is preserved for backwards compatibility. 2146** Use of this interface is not recommended. 2147** 2148** Definition: A <b>result table</b> is memory data structure created by the 2149** [sqlite3_get_table()] interface. A result table records the 2150** complete query results from one or more queries. 2151** 2152** The table conceptually has a number of rows and columns. But 2153** these numbers are not part of the result table itself. These 2154** numbers are obtained separately. Let N be the number of rows 2155** and M be the number of columns. 2156** 2157** A result table is an array of pointers to zero-terminated UTF-8 strings. 2158** There are (N+1)*M elements in the array. The first M pointers point 2159** to zero-terminated strings that contain the names of the columns. 2160** The remaining entries all point to query results. NULL values result 2161** in NULL pointers. All other values are in their UTF-8 zero-terminated 2162** string representation as returned by [sqlite3_column_text()]. 2163** 2164** A result table might consist of one or more memory allocations. 2165** It is not safe to pass a result table directly to [sqlite3_free()]. 2166** A result table should be deallocated using [sqlite3_free_table()]. 2167** 2168** ^(As an example of the result table format, suppose a query result 2169** is as follows: 2170** 2171** <blockquote><pre> 2172** Name | Age 2173** ----------------------- 2174** Alice | 43 2175** Bob | 28 2176** Cindy | 21 2177** </pre></blockquote> 2178** 2179** There are two column (M==2) and three rows (N==3). Thus the 2180** result table has 8 entries. Suppose the result table is stored 2181** in an array names azResult. Then azResult holds this content: 2182** 2183** <blockquote><pre> 2184** azResult[0] = "Name"; 2185** azResult[1] = "Age"; 2186** azResult[2] = "Alice"; 2187** azResult[3] = "43"; 2188** azResult[4] = "Bob"; 2189** azResult[5] = "28"; 2190** azResult[6] = "Cindy"; 2191** azResult[7] = "21"; 2192** </pre></blockquote>)^ 2193** 2194** ^The sqlite3_get_table() function evaluates one or more 2195** semicolon-separated SQL statements in the zero-terminated UTF-8 2196** string of its 2nd parameter and returns a result table to the 2197** pointer given in its 3rd parameter. 2198** 2199** After the application has finished with the result from sqlite3_get_table(), 2200** it must pass the result table pointer to sqlite3_free_table() in order to 2201** release the memory that was malloced. Because of the way the 2202** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2203** function must not try to call [sqlite3_free()] directly. Only 2204** [sqlite3_free_table()] is able to release the memory properly and safely. 2205** 2206** The sqlite3_get_table() interface is implemented as a wrapper around 2207** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2208** to any internal data structures of SQLite. It uses only the public 2209** interface defined here. As a consequence, errors that occur in the 2210** wrapper layer outside of the internal [sqlite3_exec()] call are not 2211** reflected in subsequent calls to [sqlite3_errcode()] or 2212** [sqlite3_errmsg()]. 2213*/ 2214int sqlite3_get_table( 2215 sqlite3 *db, /* An open database */ 2216 const char *zSql, /* SQL to be evaluated */ 2217 char ***pazResult, /* Results of the query */ 2218 int *pnRow, /* Number of result rows written here */ 2219 int *pnColumn, /* Number of result columns written here */ 2220 char **pzErrmsg /* Error msg written here */ 2221); 2222void sqlite3_free_table(char **result); 2223 2224/* 2225** CAPI3REF: Formatted String Printing Functions 2226** 2227** These routines are work-alikes of the "printf()" family of functions 2228** from the standard C library. 2229** 2230** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2231** results into memory obtained from [sqlite3_malloc()]. 2232** The strings returned by these two routines should be 2233** released by [sqlite3_free()]. ^Both routines return a 2234** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2235** memory to hold the resulting string. 2236** 2237** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2238** the standard C library. The result is written into the 2239** buffer supplied as the second parameter whose size is given by 2240** the first parameter. Note that the order of the 2241** first two parameters is reversed from snprintf().)^ This is an 2242** historical accident that cannot be fixed without breaking 2243** backwards compatibility. ^(Note also that sqlite3_snprintf() 2244** returns a pointer to its buffer instead of the number of 2245** characters actually written into the buffer.)^ We admit that 2246** the number of characters written would be a more useful return 2247** value but we cannot change the implementation of sqlite3_snprintf() 2248** now without breaking compatibility. 2249** 2250** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2251** guarantees that the buffer is always zero-terminated. ^The first 2252** parameter "n" is the total size of the buffer, including space for 2253** the zero terminator. So the longest string that can be completely 2254** written will be n-1 characters. 2255** 2256** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2257** 2258** These routines all implement some additional formatting 2259** options that are useful for constructing SQL statements. 2260** All of the usual printf() formatting options apply. In addition, there 2261** is are "%q", "%Q", and "%z" options. 2262** 2263** ^(The %q option works like %s in that it substitutes a nul-terminated 2264** string from the argument list. But %q also doubles every '\'' character. 2265** %q is designed for use inside a string literal.)^ By doubling each '\'' 2266** character it escapes that character and allows it to be inserted into 2267** the string. 2268** 2269** For example, assume the string variable zText contains text as follows: 2270** 2271** <blockquote><pre> 2272** char *zText = "It's a happy day!"; 2273** </pre></blockquote> 2274** 2275** One can use this text in an SQL statement as follows: 2276** 2277** <blockquote><pre> 2278** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2279** sqlite3_exec(db, zSQL, 0, 0, 0); 2280** sqlite3_free(zSQL); 2281** </pre></blockquote> 2282** 2283** Because the %q format string is used, the '\'' character in zText 2284** is escaped and the SQL generated is as follows: 2285** 2286** <blockquote><pre> 2287** INSERT INTO table1 VALUES('It''s a happy day!') 2288** </pre></blockquote> 2289** 2290** This is correct. Had we used %s instead of %q, the generated SQL 2291** would have looked like this: 2292** 2293** <blockquote><pre> 2294** INSERT INTO table1 VALUES('It's a happy day!'); 2295** </pre></blockquote> 2296** 2297** This second example is an SQL syntax error. As a general rule you should 2298** always use %q instead of %s when inserting text into a string literal. 2299** 2300** ^(The %Q option works like %q except it also adds single quotes around 2301** the outside of the total string. Additionally, if the parameter in the 2302** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2303** single quotes).)^ So, for example, one could say: 2304** 2305** <blockquote><pre> 2306** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2307** sqlite3_exec(db, zSQL, 0, 0, 0); 2308** sqlite3_free(zSQL); 2309** </pre></blockquote> 2310** 2311** The code above will render a correct SQL statement in the zSQL 2312** variable even if the zText variable is a NULL pointer. 2313** 2314** ^(The "%z" formatting option works like "%s" but with the 2315** addition that after the string has been read and copied into 2316** the result, [sqlite3_free()] is called on the input string.)^ 2317*/ 2318char *sqlite3_mprintf(const char*,...); 2319char *sqlite3_vmprintf(const char*, va_list); 2320char *sqlite3_snprintf(int,char*,const char*, ...); 2321char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2322 2323/* 2324** CAPI3REF: Memory Allocation Subsystem 2325** 2326** The SQLite core uses these three routines for all of its own 2327** internal memory allocation needs. "Core" in the previous sentence 2328** does not include operating-system specific VFS implementation. The 2329** Windows VFS uses native malloc() and free() for some operations. 2330** 2331** ^The sqlite3_malloc() routine returns a pointer to a block 2332** of memory at least N bytes in length, where N is the parameter. 2333** ^If sqlite3_malloc() is unable to obtain sufficient free 2334** memory, it returns a NULL pointer. ^If the parameter N to 2335** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2336** a NULL pointer. 2337** 2338** ^The sqlite3_malloc64(N) routine works just like 2339** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2340** of a signed 32-bit integer. 2341** 2342** ^Calling sqlite3_free() with a pointer previously returned 2343** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2344** that it might be reused. ^The sqlite3_free() routine is 2345** a no-op if is called with a NULL pointer. Passing a NULL pointer 2346** to sqlite3_free() is harmless. After being freed, memory 2347** should neither be read nor written. Even reading previously freed 2348** memory might result in a segmentation fault or other severe error. 2349** Memory corruption, a segmentation fault, or other severe error 2350** might result if sqlite3_free() is called with a non-NULL pointer that 2351** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2352** 2353** ^The sqlite3_realloc(X,N) interface attempts to resize a 2354** prior memory allocation X to be at least N bytes. 2355** ^If the X parameter to sqlite3_realloc(X,N) 2356** is a NULL pointer then its behavior is identical to calling 2357** sqlite3_malloc(N). 2358** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2359** negative then the behavior is exactly the same as calling 2360** sqlite3_free(X). 2361** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2362** of at least N bytes in size or NULL if insufficient memory is available. 2363** ^If M is the size of the prior allocation, then min(N,M) bytes 2364** of the prior allocation are copied into the beginning of buffer returned 2365** by sqlite3_realloc(X,N) and the prior allocation is freed. 2366** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2367** prior allocation is not freed. 2368** 2369** ^The sqlite3_realloc64(X,N) interfaces works the same as 2370** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2371** of a 32-bit signed integer. 2372** 2373** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2374** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2375** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2376** ^The value returned by sqlite3_msize(X) might be larger than the number 2377** of bytes requested when X was allocated. ^If X is a NULL pointer then 2378** sqlite3_msize(X) returns zero. If X points to something that is not 2379** the beginning of memory allocation, or if it points to a formerly 2380** valid memory allocation that has now been freed, then the behavior 2381** of sqlite3_msize(X) is undefined and possibly harmful. 2382** 2383** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2384** sqlite3_malloc64(), and sqlite3_realloc64() 2385** is always aligned to at least an 8 byte boundary, or to a 2386** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2387** option is used. 2388** 2389** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2390** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2391** implementation of these routines to be omitted. That capability 2392** is no longer provided. Only built-in memory allocators can be used. 2393** 2394** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2395** the system malloc() and free() directly when converting 2396** filenames between the UTF-8 encoding used by SQLite 2397** and whatever filename encoding is used by the particular Windows 2398** installation. Memory allocation errors were detected, but 2399** they were reported back as [SQLITE_CANTOPEN] or 2400** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2401** 2402** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2403** must be either NULL or else pointers obtained from a prior 2404** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2405** not yet been released. 2406** 2407** The application must not read or write any part of 2408** a block of memory after it has been released using 2409** [sqlite3_free()] or [sqlite3_realloc()]. 2410*/ 2411void *sqlite3_malloc(int); 2412void *sqlite3_malloc64(sqlite3_uint64); 2413void *sqlite3_realloc(void*, int); 2414void *sqlite3_realloc64(void*, sqlite3_uint64); 2415void sqlite3_free(void*); 2416sqlite3_uint64 sqlite3_msize(void*); 2417 2418/* 2419** CAPI3REF: Memory Allocator Statistics 2420** 2421** SQLite provides these two interfaces for reporting on the status 2422** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2423** routines, which form the built-in memory allocation subsystem. 2424** 2425** ^The [sqlite3_memory_used()] routine returns the number of bytes 2426** of memory currently outstanding (malloced but not freed). 2427** ^The [sqlite3_memory_highwater()] routine returns the maximum 2428** value of [sqlite3_memory_used()] since the high-water mark 2429** was last reset. ^The values returned by [sqlite3_memory_used()] and 2430** [sqlite3_memory_highwater()] include any overhead 2431** added by SQLite in its implementation of [sqlite3_malloc()], 2432** but not overhead added by the any underlying system library 2433** routines that [sqlite3_malloc()] may call. 2434** 2435** ^The memory high-water mark is reset to the current value of 2436** [sqlite3_memory_used()] if and only if the parameter to 2437** [sqlite3_memory_highwater()] is true. ^The value returned 2438** by [sqlite3_memory_highwater(1)] is the high-water mark 2439** prior to the reset. 2440*/ 2441sqlite3_int64 sqlite3_memory_used(void); 2442sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2443 2444/* 2445** CAPI3REF: Pseudo-Random Number Generator 2446** 2447** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2448** select random [ROWID | ROWIDs] when inserting new records into a table that 2449** already uses the largest possible [ROWID]. The PRNG is also used for 2450** the build-in random() and randomblob() SQL functions. This interface allows 2451** applications to access the same PRNG for other purposes. 2452** 2453** ^A call to this routine stores N bytes of randomness into buffer P. 2454** ^The P parameter can be a NULL pointer. 2455** 2456** ^If this routine has not been previously called or if the previous 2457** call had N less than one or a NULL pointer for P, then the PRNG is 2458** seeded using randomness obtained from the xRandomness method of 2459** the default [sqlite3_vfs] object. 2460** ^If the previous call to this routine had an N of 1 or more and a 2461** non-NULL P then the pseudo-randomness is generated 2462** internally and without recourse to the [sqlite3_vfs] xRandomness 2463** method. 2464*/ 2465void sqlite3_randomness(int N, void *P); 2466 2467/* 2468** CAPI3REF: Compile-Time Authorization Callbacks 2469** 2470** ^This routine registers an authorizer callback with a particular 2471** [database connection], supplied in the first argument. 2472** ^The authorizer callback is invoked as SQL statements are being compiled 2473** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2474** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2475** points during the compilation process, as logic is being created 2476** to perform various actions, the authorizer callback is invoked to 2477** see if those actions are allowed. ^The authorizer callback should 2478** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2479** specific action but allow the SQL statement to continue to be 2480** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2481** rejected with an error. ^If the authorizer callback returns 2482** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2483** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2484** the authorizer will fail with an error message. 2485** 2486** When the callback returns [SQLITE_OK], that means the operation 2487** requested is ok. ^When the callback returns [SQLITE_DENY], the 2488** [sqlite3_prepare_v2()] or equivalent call that triggered the 2489** authorizer will fail with an error message explaining that 2490** access is denied. 2491** 2492** ^The first parameter to the authorizer callback is a copy of the third 2493** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2494** to the callback is an integer [SQLITE_COPY | action code] that specifies 2495** the particular action to be authorized. ^The third through sixth parameters 2496** to the callback are zero-terminated strings that contain additional 2497** details about the action to be authorized. 2498** 2499** ^If the action code is [SQLITE_READ] 2500** and the callback returns [SQLITE_IGNORE] then the 2501** [prepared statement] statement is constructed to substitute 2502** a NULL value in place of the table column that would have 2503** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2504** return can be used to deny an untrusted user access to individual 2505** columns of a table. 2506** ^If the action code is [SQLITE_DELETE] and the callback returns 2507** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2508** [truncate optimization] is disabled and all rows are deleted individually. 2509** 2510** An authorizer is used when [sqlite3_prepare | preparing] 2511** SQL statements from an untrusted source, to ensure that the SQL statements 2512** do not try to access data they are not allowed to see, or that they do not 2513** try to execute malicious statements that damage the database. For 2514** example, an application may allow a user to enter arbitrary 2515** SQL queries for evaluation by a database. But the application does 2516** not want the user to be able to make arbitrary changes to the 2517** database. An authorizer could then be put in place while the 2518** user-entered SQL is being [sqlite3_prepare | prepared] that 2519** disallows everything except [SELECT] statements. 2520** 2521** Applications that need to process SQL from untrusted sources 2522** might also consider lowering resource limits using [sqlite3_limit()] 2523** and limiting database size using the [max_page_count] [PRAGMA] 2524** in addition to using an authorizer. 2525** 2526** ^(Only a single authorizer can be in place on a database connection 2527** at a time. Each call to sqlite3_set_authorizer overrides the 2528** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2529** The authorizer is disabled by default. 2530** 2531** The authorizer callback must not do anything that will modify 2532** the database connection that invoked the authorizer callback. 2533** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2534** database connections for the meaning of "modify" in this paragraph. 2535** 2536** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2537** statement might be re-prepared during [sqlite3_step()] due to a 2538** schema change. Hence, the application should ensure that the 2539** correct authorizer callback remains in place during the [sqlite3_step()]. 2540** 2541** ^Note that the authorizer callback is invoked only during 2542** [sqlite3_prepare()] or its variants. Authorization is not 2543** performed during statement evaluation in [sqlite3_step()], unless 2544** as stated in the previous paragraph, sqlite3_step() invokes 2545** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2546*/ 2547int sqlite3_set_authorizer( 2548 sqlite3*, 2549 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2550 void *pUserData 2551); 2552 2553/* 2554** CAPI3REF: Authorizer Return Codes 2555** 2556** The [sqlite3_set_authorizer | authorizer callback function] must 2557** return either [SQLITE_OK] or one of these two constants in order 2558** to signal SQLite whether or not the action is permitted. See the 2559** [sqlite3_set_authorizer | authorizer documentation] for additional 2560** information. 2561** 2562** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2563** returned from the [sqlite3_vtab_on_conflict()] interface. 2564*/ 2565#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2566#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2567 2568/* 2569** CAPI3REF: Authorizer Action Codes 2570** 2571** The [sqlite3_set_authorizer()] interface registers a callback function 2572** that is invoked to authorize certain SQL statement actions. The 2573** second parameter to the callback is an integer code that specifies 2574** what action is being authorized. These are the integer action codes that 2575** the authorizer callback may be passed. 2576** 2577** These action code values signify what kind of operation is to be 2578** authorized. The 3rd and 4th parameters to the authorization 2579** callback function will be parameters or NULL depending on which of these 2580** codes is used as the second parameter. ^(The 5th parameter to the 2581** authorizer callback is the name of the database ("main", "temp", 2582** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2583** is the name of the inner-most trigger or view that is responsible for 2584** the access attempt or NULL if this access attempt is directly from 2585** top-level SQL code. 2586*/ 2587/******************************************* 3rd ************ 4th ***********/ 2588#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2589#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2590#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2591#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2592#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2593#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2594#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2595#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2596#define SQLITE_DELETE 9 /* Table Name NULL */ 2597#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2598#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2599#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2600#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2601#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2602#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2603#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2604#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2605#define SQLITE_INSERT 18 /* Table Name NULL */ 2606#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2607#define SQLITE_READ 20 /* Table Name Column Name */ 2608#define SQLITE_SELECT 21 /* NULL NULL */ 2609#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2610#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2611#define SQLITE_ATTACH 24 /* Filename NULL */ 2612#define SQLITE_DETACH 25 /* Database Name NULL */ 2613#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2614#define SQLITE_REINDEX 27 /* Index Name NULL */ 2615#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2616#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2617#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2618#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2619#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2620#define SQLITE_COPY 0 /* No longer used */ 2621#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2622 2623/* 2624** CAPI3REF: Tracing And Profiling Functions 2625** 2626** These routines register callback functions that can be used for 2627** tracing and profiling the execution of SQL statements. 2628** 2629** ^The callback function registered by sqlite3_trace() is invoked at 2630** various times when an SQL statement is being run by [sqlite3_step()]. 2631** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2632** SQL statement text as the statement first begins executing. 2633** ^(Additional sqlite3_trace() callbacks might occur 2634** as each triggered subprogram is entered. The callbacks for triggers 2635** contain a UTF-8 SQL comment that identifies the trigger.)^ 2636** 2637** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2638** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2639** 2640** ^The callback function registered by sqlite3_profile() is invoked 2641** as each SQL statement finishes. ^The profile callback contains 2642** the original statement text and an estimate of wall-clock time 2643** of how long that statement took to run. ^The profile callback 2644** time is in units of nanoseconds, however the current implementation 2645** is only capable of millisecond resolution so the six least significant 2646** digits in the time are meaningless. Future versions of SQLite 2647** might provide greater resolution on the profiler callback. The 2648** sqlite3_profile() function is considered experimental and is 2649** subject to change in future versions of SQLite. 2650*/ 2651void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2652SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2653 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2654 2655/* 2656** CAPI3REF: Query Progress Callbacks 2657** 2658** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2659** function X to be invoked periodically during long running calls to 2660** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2661** database connection D. An example use for this 2662** interface is to keep a GUI updated during a large query. 2663** 2664** ^The parameter P is passed through as the only parameter to the 2665** callback function X. ^The parameter N is the approximate number of 2666** [virtual machine instructions] that are evaluated between successive 2667** invocations of the callback X. ^If N is less than one then the progress 2668** handler is disabled. 2669** 2670** ^Only a single progress handler may be defined at one time per 2671** [database connection]; setting a new progress handler cancels the 2672** old one. ^Setting parameter X to NULL disables the progress handler. 2673** ^The progress handler is also disabled by setting N to a value less 2674** than 1. 2675** 2676** ^If the progress callback returns non-zero, the operation is 2677** interrupted. This feature can be used to implement a 2678** "Cancel" button on a GUI progress dialog box. 2679** 2680** The progress handler callback must not do anything that will modify 2681** the database connection that invoked the progress handler. 2682** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2683** database connections for the meaning of "modify" in this paragraph. 2684** 2685*/ 2686void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2687 2688/* 2689** CAPI3REF: Opening A New Database Connection 2690** 2691** ^These routines open an SQLite database file as specified by the 2692** filename argument. ^The filename argument is interpreted as UTF-8 for 2693** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2694** order for sqlite3_open16(). ^(A [database connection] handle is usually 2695** returned in *ppDb, even if an error occurs. The only exception is that 2696** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2697** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2698** object.)^ ^(If the database is opened (and/or created) successfully, then 2699** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2700** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2701** an English language description of the error following a failure of any 2702** of the sqlite3_open() routines. 2703** 2704** ^The default encoding will be UTF-8 for databases created using 2705** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 2706** created using sqlite3_open16() will be UTF-16 in the native byte order. 2707** 2708** Whether or not an error occurs when it is opened, resources 2709** associated with the [database connection] handle should be released by 2710** passing it to [sqlite3_close()] when it is no longer required. 2711** 2712** The sqlite3_open_v2() interface works like sqlite3_open() 2713** except that it accepts two additional parameters for additional control 2714** over the new database connection. ^(The flags parameter to 2715** sqlite3_open_v2() can take one of 2716** the following three values, optionally combined with the 2717** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2718** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2719** 2720** <dl> 2721** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2722** <dd>The database is opened in read-only mode. If the database does not 2723** already exist, an error is returned.</dd>)^ 2724** 2725** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2726** <dd>The database is opened for reading and writing if possible, or reading 2727** only if the file is write protected by the operating system. In either 2728** case the database must already exist, otherwise an error is returned.</dd>)^ 2729** 2730** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2731** <dd>The database is opened for reading and writing, and is created if 2732** it does not already exist. This is the behavior that is always used for 2733** sqlite3_open() and sqlite3_open16().</dd>)^ 2734** </dl> 2735** 2736** If the 3rd parameter to sqlite3_open_v2() is not one of the 2737** combinations shown above optionally combined with other 2738** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2739** then the behavior is undefined. 2740** 2741** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2742** opens in the multi-thread [threading mode] as long as the single-thread 2743** mode has not been set at compile-time or start-time. ^If the 2744** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2745** in the serialized [threading mode] unless single-thread was 2746** previously selected at compile-time or start-time. 2747** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2748** eligible to use [shared cache mode], regardless of whether or not shared 2749** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2750** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2751** participate in [shared cache mode] even if it is enabled. 2752** 2753** ^The fourth parameter to sqlite3_open_v2() is the name of the 2754** [sqlite3_vfs] object that defines the operating system interface that 2755** the new database connection should use. ^If the fourth parameter is 2756** a NULL pointer then the default [sqlite3_vfs] object is used. 2757** 2758** ^If the filename is ":memory:", then a private, temporary in-memory database 2759** is created for the connection. ^This in-memory database will vanish when 2760** the database connection is closed. Future versions of SQLite might 2761** make use of additional special filenames that begin with the ":" character. 2762** It is recommended that when a database filename actually does begin with 2763** a ":" character you should prefix the filename with a pathname such as 2764** "./" to avoid ambiguity. 2765** 2766** ^If the filename is an empty string, then a private, temporary 2767** on-disk database will be created. ^This private database will be 2768** automatically deleted as soon as the database connection is closed. 2769** 2770** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2771** 2772** ^If [URI filename] interpretation is enabled, and the filename argument 2773** begins with "file:", then the filename is interpreted as a URI. ^URI 2774** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2775** set in the fourth argument to sqlite3_open_v2(), or if it has 2776** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2777** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2778** As of SQLite version 3.7.7, URI filename interpretation is turned off 2779** by default, but future releases of SQLite might enable URI filename 2780** interpretation by default. See "[URI filenames]" for additional 2781** information. 2782** 2783** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2784** authority, then it must be either an empty string or the string 2785** "localhost". ^If the authority is not an empty string or "localhost", an 2786** error is returned to the caller. ^The fragment component of a URI, if 2787** present, is ignored. 2788** 2789** ^SQLite uses the path component of the URI as the name of the disk file 2790** which contains the database. ^If the path begins with a '/' character, 2791** then it is interpreted as an absolute path. ^If the path does not begin 2792** with a '/' (meaning that the authority section is omitted from the URI) 2793** then the path is interpreted as a relative path. 2794** ^(On windows, the first component of an absolute path 2795** is a drive specification (e.g. "C:").)^ 2796** 2797** [[core URI query parameters]] 2798** The query component of a URI may contain parameters that are interpreted 2799** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2800** SQLite and its built-in [VFSes] interpret the 2801** following query parameters: 2802** 2803** <ul> 2804** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2805** a VFS object that provides the operating system interface that should 2806** be used to access the database file on disk. ^If this option is set to 2807** an empty string the default VFS object is used. ^Specifying an unknown 2808** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2809** present, then the VFS specified by the option takes precedence over 2810** the value passed as the fourth parameter to sqlite3_open_v2(). 2811** 2812** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 2813** "rwc", or "memory". Attempting to set it to any other value is 2814** an error)^. 2815** ^If "ro" is specified, then the database is opened for read-only 2816** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2817** third argument to sqlite3_open_v2(). ^If the mode option is set to 2818** "rw", then the database is opened for read-write (but not create) 2819** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2820** been set. ^Value "rwc" is equivalent to setting both 2821** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 2822** set to "memory" then a pure [in-memory database] that never reads 2823** or writes from disk is used. ^It is an error to specify a value for 2824** the mode parameter that is less restrictive than that specified by 2825** the flags passed in the third parameter to sqlite3_open_v2(). 2826** 2827** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2828** "private". ^Setting it to "shared" is equivalent to setting the 2829** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2830** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2831** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2832** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2833** a URI filename, its value overrides any behavior requested by setting 2834** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2835** 2836** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 2837** [powersafe overwrite] property does or does not apply to the 2838** storage media on which the database file resides. 2839** 2840** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 2841** which if set disables file locking in rollback journal modes. This 2842** is useful for accessing a database on a filesystem that does not 2843** support locking. Caution: Database corruption might result if two 2844** or more processes write to the same database and any one of those 2845** processes uses nolock=1. 2846** 2847** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 2848** parameter that indicates that the database file is stored on 2849** read-only media. ^When immutable is set, SQLite assumes that the 2850** database file cannot be changed, even by a process with higher 2851** privilege, and so the database is opened read-only and all locking 2852** and change detection is disabled. Caution: Setting the immutable 2853** property on a database file that does in fact change can result 2854** in incorrect query results and/or [SQLITE_CORRUPT] errors. 2855** See also: [SQLITE_IOCAP_IMMUTABLE]. 2856** 2857** </ul> 2858** 2859** ^Specifying an unknown parameter in the query component of a URI is not an 2860** error. Future versions of SQLite might understand additional query 2861** parameters. See "[query parameters with special meaning to SQLite]" for 2862** additional information. 2863** 2864** [[URI filename examples]] <h3>URI filename examples</h3> 2865** 2866** <table border="1" align=center cellpadding=5> 2867** <tr><th> URI filenames <th> Results 2868** <tr><td> file:data.db <td> 2869** Open the file "data.db" in the current directory. 2870** <tr><td> file:/home/fred/data.db<br> 2871** file:///home/fred/data.db <br> 2872** file://localhost/home/fred/data.db <br> <td> 2873** Open the database file "/home/fred/data.db". 2874** <tr><td> file://darkstar/home/fred/data.db <td> 2875** An error. "darkstar" is not a recognized authority. 2876** <tr><td style="white-space:nowrap"> 2877** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2878** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2879** C:. Note that the %20 escaping in this example is not strictly 2880** necessary - space characters can be used literally 2881** in URI filenames. 2882** <tr><td> file:data.db?mode=ro&cache=private <td> 2883** Open file "data.db" in the current directory for read-only access. 2884** Regardless of whether or not shared-cache mode is enabled by 2885** default, use a private cache. 2886** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 2887** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 2888** that uses dot-files in place of posix advisory locking. 2889** <tr><td> file:data.db?mode=readonly <td> 2890** An error. "readonly" is not a valid option for the "mode" parameter. 2891** </table> 2892** 2893** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2894** query components of a URI. A hexadecimal escape sequence consists of a 2895** percent sign - "%" - followed by exactly two hexadecimal digits 2896** specifying an octet value. ^Before the path or query components of a 2897** URI filename are interpreted, they are encoded using UTF-8 and all 2898** hexadecimal escape sequences replaced by a single byte containing the 2899** corresponding octet. If this process generates an invalid UTF-8 encoding, 2900** the results are undefined. 2901** 2902** <b>Note to Windows users:</b> The encoding used for the filename argument 2903** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2904** codepage is currently defined. Filenames containing international 2905** characters must be converted to UTF-8 prior to passing them into 2906** sqlite3_open() or sqlite3_open_v2(). 2907** 2908** <b>Note to Windows Runtime users:</b> The temporary directory must be set 2909** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 2910** features that require the use of temporary files may fail. 2911** 2912** See also: [sqlite3_temp_directory] 2913*/ 2914int sqlite3_open( 2915 const char *filename, /* Database filename (UTF-8) */ 2916 sqlite3 **ppDb /* OUT: SQLite db handle */ 2917); 2918int sqlite3_open16( 2919 const void *filename, /* Database filename (UTF-16) */ 2920 sqlite3 **ppDb /* OUT: SQLite db handle */ 2921); 2922int sqlite3_open_v2( 2923 const char *filename, /* Database filename (UTF-8) */ 2924 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2925 int flags, /* Flags */ 2926 const char *zVfs /* Name of VFS module to use */ 2927); 2928 2929/* 2930** CAPI3REF: Obtain Values For URI Parameters 2931** 2932** These are utility routines, useful to VFS implementations, that check 2933** to see if a database file was a URI that contained a specific query 2934** parameter, and if so obtains the value of that query parameter. 2935** 2936** If F is the database filename pointer passed into the xOpen() method of 2937** a VFS implementation when the flags parameter to xOpen() has one or 2938** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 2939** P is the name of the query parameter, then 2940** sqlite3_uri_parameter(F,P) returns the value of the P 2941** parameter if it exists or a NULL pointer if P does not appear as a 2942** query parameter on F. If P is a query parameter of F 2943** has no explicit value, then sqlite3_uri_parameter(F,P) returns 2944** a pointer to an empty string. 2945** 2946** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 2947** parameter and returns true (1) or false (0) according to the value 2948** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 2949** value of query parameter P is one of "yes", "true", or "on" in any 2950** case or if the value begins with a non-zero number. The 2951** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 2952** query parameter P is one of "no", "false", or "off" in any case or 2953** if the value begins with a numeric zero. If P is not a query 2954** parameter on F or if the value of P is does not match any of the 2955** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 2956** 2957** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 2958** 64-bit signed integer and returns that integer, or D if P does not 2959** exist. If the value of P is something other than an integer, then 2960** zero is returned. 2961** 2962** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 2963** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 2964** is not a database file pathname pointer that SQLite passed into the xOpen 2965** VFS method, then the behavior of this routine is undefined and probably 2966** undesirable. 2967*/ 2968const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 2969int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 2970sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 2971 2972 2973/* 2974** CAPI3REF: Error Codes And Messages 2975** 2976** ^The sqlite3_errcode() interface returns the numeric [result code] or 2977** [extended result code] for the most recent failed sqlite3_* API call 2978** associated with a [database connection]. If a prior API call failed 2979** but the most recent API call succeeded, the return value from 2980** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2981** interface is the same except that it always returns the 2982** [extended result code] even when extended result codes are 2983** disabled. 2984** 2985** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2986** text that describes the error, as either UTF-8 or UTF-16 respectively. 2987** ^(Memory to hold the error message string is managed internally. 2988** The application does not need to worry about freeing the result. 2989** However, the error string might be overwritten or deallocated by 2990** subsequent calls to other SQLite interface functions.)^ 2991** 2992** ^The sqlite3_errstr() interface returns the English-language text 2993** that describes the [result code], as UTF-8. 2994** ^(Memory to hold the error message string is managed internally 2995** and must not be freed by the application)^. 2996** 2997** When the serialized [threading mode] is in use, it might be the 2998** case that a second error occurs on a separate thread in between 2999** the time of the first error and the call to these interfaces. 3000** When that happens, the second error will be reported since these 3001** interfaces always report the most recent result. To avoid 3002** this, each thread can obtain exclusive use of the [database connection] D 3003** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3004** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3005** all calls to the interfaces listed here are completed. 3006** 3007** If an interface fails with SQLITE_MISUSE, that means the interface 3008** was invoked incorrectly by the application. In that case, the 3009** error code and message may or may not be set. 3010*/ 3011int sqlite3_errcode(sqlite3 *db); 3012int sqlite3_extended_errcode(sqlite3 *db); 3013const char *sqlite3_errmsg(sqlite3*); 3014const void *sqlite3_errmsg16(sqlite3*); 3015const char *sqlite3_errstr(int); 3016 3017/* 3018** CAPI3REF: SQL Statement Object 3019** KEYWORDS: {prepared statement} {prepared statements} 3020** 3021** An instance of this object represents a single SQL statement. 3022** This object is variously known as a "prepared statement" or a 3023** "compiled SQL statement" or simply as a "statement". 3024** 3025** The life of a statement object goes something like this: 3026** 3027** <ol> 3028** <li> Create the object using [sqlite3_prepare_v2()] or a related 3029** function. 3030** <li> Bind values to [host parameters] using the sqlite3_bind_*() 3031** interfaces. 3032** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3033** <li> Reset the statement using [sqlite3_reset()] then go back 3034** to step 2. Do this zero or more times. 3035** <li> Destroy the object using [sqlite3_finalize()]. 3036** </ol> 3037** 3038** Refer to documentation on individual methods above for additional 3039** information. 3040*/ 3041typedef struct sqlite3_stmt sqlite3_stmt; 3042 3043/* 3044** CAPI3REF: Run-time Limits 3045** 3046** ^(This interface allows the size of various constructs to be limited 3047** on a connection by connection basis. The first parameter is the 3048** [database connection] whose limit is to be set or queried. The 3049** second parameter is one of the [limit categories] that define a 3050** class of constructs to be size limited. The third parameter is the 3051** new limit for that construct.)^ 3052** 3053** ^If the new limit is a negative number, the limit is unchanged. 3054** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3055** [limits | hard upper bound] 3056** set at compile-time by a C preprocessor macro called 3057** [limits | SQLITE_MAX_<i>NAME</i>]. 3058** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3059** ^Attempts to increase a limit above its hard upper bound are 3060** silently truncated to the hard upper bound. 3061** 3062** ^Regardless of whether or not the limit was changed, the 3063** [sqlite3_limit()] interface returns the prior value of the limit. 3064** ^Hence, to find the current value of a limit without changing it, 3065** simply invoke this interface with the third parameter set to -1. 3066** 3067** Run-time limits are intended for use in applications that manage 3068** both their own internal database and also databases that are controlled 3069** by untrusted external sources. An example application might be a 3070** web browser that has its own databases for storing history and 3071** separate databases controlled by JavaScript applications downloaded 3072** off the Internet. The internal databases can be given the 3073** large, default limits. Databases managed by external sources can 3074** be given much smaller limits designed to prevent a denial of service 3075** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3076** interface to further control untrusted SQL. The size of the database 3077** created by an untrusted script can be contained using the 3078** [max_page_count] [PRAGMA]. 3079** 3080** New run-time limit categories may be added in future releases. 3081*/ 3082int sqlite3_limit(sqlite3*, int id, int newVal); 3083 3084/* 3085** CAPI3REF: Run-Time Limit Categories 3086** KEYWORDS: {limit category} {*limit categories} 3087** 3088** These constants define various performance limits 3089** that can be lowered at run-time using [sqlite3_limit()]. 3090** The synopsis of the meanings of the various limits is shown below. 3091** Additional information is available at [limits | Limits in SQLite]. 3092** 3093** <dl> 3094** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3095** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3096** 3097** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3098** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3099** 3100** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3101** <dd>The maximum number of columns in a table definition or in the 3102** result set of a [SELECT] or the maximum number of columns in an index 3103** or in an ORDER BY or GROUP BY clause.</dd>)^ 3104** 3105** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3106** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3107** 3108** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3109** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3110** 3111** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3112** <dd>The maximum number of instructions in a virtual machine program 3113** used to implement an SQL statement. This limit is not currently 3114** enforced, though that might be added in some future release of 3115** SQLite.</dd>)^ 3116** 3117** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3118** <dd>The maximum number of arguments on a function.</dd>)^ 3119** 3120** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3121** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3122** 3123** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3124** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3125** <dd>The maximum length of the pattern argument to the [LIKE] or 3126** [GLOB] operators.</dd>)^ 3127** 3128** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3129** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3130** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3131** 3132** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3133** <dd>The maximum depth of recursion for triggers.</dd>)^ 3134** 3135** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3136** <dd>The maximum number of auxiliary worker threads that a single 3137** [prepared statement] may start.</dd>)^ 3138** </dl> 3139*/ 3140#define SQLITE_LIMIT_LENGTH 0 3141#define SQLITE_LIMIT_SQL_LENGTH 1 3142#define SQLITE_LIMIT_COLUMN 2 3143#define SQLITE_LIMIT_EXPR_DEPTH 3 3144#define SQLITE_LIMIT_COMPOUND_SELECT 4 3145#define SQLITE_LIMIT_VDBE_OP 5 3146#define SQLITE_LIMIT_FUNCTION_ARG 6 3147#define SQLITE_LIMIT_ATTACHED 7 3148#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3149#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3150#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3151#define SQLITE_LIMIT_WORKER_THREADS 11 3152 3153/* 3154** CAPI3REF: Compiling An SQL Statement 3155** KEYWORDS: {SQL statement compiler} 3156** 3157** To execute an SQL query, it must first be compiled into a byte-code 3158** program using one of these routines. 3159** 3160** The first argument, "db", is a [database connection] obtained from a 3161** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3162** [sqlite3_open16()]. The database connection must not have been closed. 3163** 3164** The second argument, "zSql", is the statement to be compiled, encoded 3165** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 3166** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 3167** use UTF-16. 3168** 3169** ^If the nByte argument is less than zero, then zSql is read up to the 3170** first zero terminator. ^If nByte is non-negative, then it is the maximum 3171** number of bytes read from zSql. ^When nByte is non-negative, the 3172** zSql string ends at either the first '\000' or '\u0000' character or 3173** the nByte-th byte, whichever comes first. If the caller knows 3174** that the supplied string is nul-terminated, then there is a small 3175** performance advantage to be gained by passing an nByte parameter that 3176** is equal to the number of bytes in the input string <i>including</i> 3177** the nul-terminator bytes as this saves SQLite from having to 3178** make a copy of the input string. 3179** 3180** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3181** past the end of the first SQL statement in zSql. These routines only 3182** compile the first statement in zSql, so *pzTail is left pointing to 3183** what remains uncompiled. 3184** 3185** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3186** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3187** to NULL. ^If the input text contains no SQL (if the input is an empty 3188** string or a comment) then *ppStmt is set to NULL. 3189** The calling procedure is responsible for deleting the compiled 3190** SQL statement using [sqlite3_finalize()] after it has finished with it. 3191** ppStmt may not be NULL. 3192** 3193** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3194** otherwise an [error code] is returned. 3195** 3196** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 3197** recommended for all new programs. The two older interfaces are retained 3198** for backwards compatibility, but their use is discouraged. 3199** ^In the "v2" interfaces, the prepared statement 3200** that is returned (the [sqlite3_stmt] object) contains a copy of the 3201** original SQL text. This causes the [sqlite3_step()] interface to 3202** behave differently in three ways: 3203** 3204** <ol> 3205** <li> 3206** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3207** always used to do, [sqlite3_step()] will automatically recompile the SQL 3208** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3209** retries will occur before sqlite3_step() gives up and returns an error. 3210** </li> 3211** 3212** <li> 3213** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3214** [error codes] or [extended error codes]. ^The legacy behavior was that 3215** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3216** and the application would have to make a second call to [sqlite3_reset()] 3217** in order to find the underlying cause of the problem. With the "v2" prepare 3218** interfaces, the underlying reason for the error is returned immediately. 3219** </li> 3220** 3221** <li> 3222** ^If the specific value bound to [parameter | host parameter] in the 3223** WHERE clause might influence the choice of query plan for a statement, 3224** then the statement will be automatically recompiled, as if there had been 3225** a schema change, on the first [sqlite3_step()] call following any change 3226** to the [sqlite3_bind_text | bindings] of that [parameter]. 3227** ^The specific value of WHERE-clause [parameter] might influence the 3228** choice of query plan if the parameter is the left-hand side of a [LIKE] 3229** or [GLOB] operator or if the parameter is compared to an indexed column 3230** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3231** </li> 3232** </ol> 3233*/ 3234int sqlite3_prepare( 3235 sqlite3 *db, /* Database handle */ 3236 const char *zSql, /* SQL statement, UTF-8 encoded */ 3237 int nByte, /* Maximum length of zSql in bytes. */ 3238 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3239 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3240); 3241int sqlite3_prepare_v2( 3242 sqlite3 *db, /* Database handle */ 3243 const char *zSql, /* SQL statement, UTF-8 encoded */ 3244 int nByte, /* Maximum length of zSql in bytes. */ 3245 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3246 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3247); 3248int sqlite3_prepare16( 3249 sqlite3 *db, /* Database handle */ 3250 const void *zSql, /* SQL statement, UTF-16 encoded */ 3251 int nByte, /* Maximum length of zSql in bytes. */ 3252 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3253 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3254); 3255int sqlite3_prepare16_v2( 3256 sqlite3 *db, /* Database handle */ 3257 const void *zSql, /* SQL statement, UTF-16 encoded */ 3258 int nByte, /* Maximum length of zSql in bytes. */ 3259 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3260 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3261); 3262 3263/* 3264** CAPI3REF: Retrieving Statement SQL 3265** 3266** ^This interface can be used to retrieve a saved copy of the original 3267** SQL text used to create a [prepared statement] if that statement was 3268** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 3269*/ 3270const char *sqlite3_sql(sqlite3_stmt *pStmt); 3271 3272/* 3273** CAPI3REF: Determine If An SQL Statement Writes The Database 3274** 3275** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3276** and only if the [prepared statement] X makes no direct changes to 3277** the content of the database file. 3278** 3279** Note that [application-defined SQL functions] or 3280** [virtual tables] might change the database indirectly as a side effect. 3281** ^(For example, if an application defines a function "eval()" that 3282** calls [sqlite3_exec()], then the following SQL statement would 3283** change the database file through side-effects: 3284** 3285** <blockquote><pre> 3286** SELECT eval('DELETE FROM t1') FROM t2; 3287** </pre></blockquote> 3288** 3289** But because the [SELECT] statement does not change the database file 3290** directly, sqlite3_stmt_readonly() would still return true.)^ 3291** 3292** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3293** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3294** since the statements themselves do not actually modify the database but 3295** rather they control the timing of when other statements modify the 3296** database. ^The [ATTACH] and [DETACH] statements also cause 3297** sqlite3_stmt_readonly() to return true since, while those statements 3298** change the configuration of a database connection, they do not make 3299** changes to the content of the database files on disk. 3300*/ 3301int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3302 3303/* 3304** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3305** 3306** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3307** [prepared statement] S has been stepped at least once using 3308** [sqlite3_step(S)] but has not run to completion and/or has not 3309** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3310** interface returns false if S is a NULL pointer. If S is not a 3311** NULL pointer and is not a pointer to a valid [prepared statement] 3312** object, then the behavior is undefined and probably undesirable. 3313** 3314** This interface can be used in combination [sqlite3_next_stmt()] 3315** to locate all prepared statements associated with a database 3316** connection that are in need of being reset. This can be used, 3317** for example, in diagnostic routines to search for prepared 3318** statements that are holding a transaction open. 3319*/ 3320int sqlite3_stmt_busy(sqlite3_stmt*); 3321 3322/* 3323** CAPI3REF: Dynamically Typed Value Object 3324** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3325** 3326** SQLite uses the sqlite3_value object to represent all values 3327** that can be stored in a database table. SQLite uses dynamic typing 3328** for the values it stores. ^Values stored in sqlite3_value objects 3329** can be integers, floating point values, strings, BLOBs, or NULL. 3330** 3331** An sqlite3_value object may be either "protected" or "unprotected". 3332** Some interfaces require a protected sqlite3_value. Other interfaces 3333** will accept either a protected or an unprotected sqlite3_value. 3334** Every interface that accepts sqlite3_value arguments specifies 3335** whether or not it requires a protected sqlite3_value. 3336** 3337** The terms "protected" and "unprotected" refer to whether or not 3338** a mutex is held. An internal mutex is held for a protected 3339** sqlite3_value object but no mutex is held for an unprotected 3340** sqlite3_value object. If SQLite is compiled to be single-threaded 3341** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3342** or if SQLite is run in one of reduced mutex modes 3343** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3344** then there is no distinction between protected and unprotected 3345** sqlite3_value objects and they can be used interchangeably. However, 3346** for maximum code portability it is recommended that applications 3347** still make the distinction between protected and unprotected 3348** sqlite3_value objects even when not strictly required. 3349** 3350** ^The sqlite3_value objects that are passed as parameters into the 3351** implementation of [application-defined SQL functions] are protected. 3352** ^The sqlite3_value object returned by 3353** [sqlite3_column_value()] is unprotected. 3354** Unprotected sqlite3_value objects may only be used with 3355** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3356** The [sqlite3_value_blob | sqlite3_value_type()] family of 3357** interfaces require protected sqlite3_value objects. 3358*/ 3359typedef struct Mem sqlite3_value; 3360 3361/* 3362** CAPI3REF: SQL Function Context Object 3363** 3364** The context in which an SQL function executes is stored in an 3365** sqlite3_context object. ^A pointer to an sqlite3_context object 3366** is always first parameter to [application-defined SQL functions]. 3367** The application-defined SQL function implementation will pass this 3368** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3369** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3370** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3371** and/or [sqlite3_set_auxdata()]. 3372*/ 3373typedef struct sqlite3_context sqlite3_context; 3374 3375/* 3376** CAPI3REF: Binding Values To Prepared Statements 3377** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3378** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3379** 3380** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3381** literals may be replaced by a [parameter] that matches one of following 3382** templates: 3383** 3384** <ul> 3385** <li> ? 3386** <li> ?NNN 3387** <li> :VVV 3388** <li> @VVV 3389** <li> $VVV 3390** </ul> 3391** 3392** In the templates above, NNN represents an integer literal, 3393** and VVV represents an alphanumeric identifier.)^ ^The values of these 3394** parameters (also called "host parameter names" or "SQL parameters") 3395** can be set using the sqlite3_bind_*() routines defined here. 3396** 3397** ^The first argument to the sqlite3_bind_*() routines is always 3398** a pointer to the [sqlite3_stmt] object returned from 3399** [sqlite3_prepare_v2()] or its variants. 3400** 3401** ^The second argument is the index of the SQL parameter to be set. 3402** ^The leftmost SQL parameter has an index of 1. ^When the same named 3403** SQL parameter is used more than once, second and subsequent 3404** occurrences have the same index as the first occurrence. 3405** ^The index for named parameters can be looked up using the 3406** [sqlite3_bind_parameter_index()] API if desired. ^The index 3407** for "?NNN" parameters is the value of NNN. 3408** ^The NNN value must be between 1 and the [sqlite3_limit()] 3409** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3410** 3411** ^The third argument is the value to bind to the parameter. 3412** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3413** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3414** is ignored and the end result is the same as sqlite3_bind_null(). 3415** 3416** ^(In those routines that have a fourth argument, its value is the 3417** number of bytes in the parameter. To be clear: the value is the 3418** number of <u>bytes</u> in the value, not the number of characters.)^ 3419** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3420** is negative, then the length of the string is 3421** the number of bytes up to the first zero terminator. 3422** If the fourth parameter to sqlite3_bind_blob() is negative, then 3423** the behavior is undefined. 3424** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3425** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3426** that parameter must be the byte offset 3427** where the NUL terminator would occur assuming the string were NUL 3428** terminated. If any NUL characters occur at byte offsets less than 3429** the value of the fourth parameter then the resulting string value will 3430** contain embedded NULs. The result of expressions involving strings 3431** with embedded NULs is undefined. 3432** 3433** ^The fifth argument to the BLOB and string binding interfaces 3434** is a destructor used to dispose of the BLOB or 3435** string after SQLite has finished with it. ^The destructor is called 3436** to dispose of the BLOB or string even if the call to bind API fails. 3437** ^If the fifth argument is 3438** the special value [SQLITE_STATIC], then SQLite assumes that the 3439** information is in static, unmanaged space and does not need to be freed. 3440** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3441** SQLite makes its own private copy of the data immediately, before 3442** the sqlite3_bind_*() routine returns. 3443** 3444** ^The sixth argument to sqlite3_bind_text64() must be one of 3445** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3446** to specify the encoding of the text in the third parameter. If 3447** the sixth argument to sqlite3_bind_text64() is not one of the 3448** allowed values shown above, or if the text encoding is different 3449** from the encoding specified by the sixth parameter, then the behavior 3450** is undefined. 3451** 3452** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3453** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3454** (just an integer to hold its size) while it is being processed. 3455** Zeroblobs are intended to serve as placeholders for BLOBs whose 3456** content is later written using 3457** [sqlite3_blob_open | incremental BLOB I/O] routines. 3458** ^A negative value for the zeroblob results in a zero-length BLOB. 3459** 3460** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3461** for the [prepared statement] or with a prepared statement for which 3462** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3463** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3464** routine is passed a [prepared statement] that has been finalized, the 3465** result is undefined and probably harmful. 3466** 3467** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3468** ^Unbound parameters are interpreted as NULL. 3469** 3470** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3471** [error code] if anything goes wrong. 3472** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3473** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3474** [SQLITE_MAX_LENGTH]. 3475** ^[SQLITE_RANGE] is returned if the parameter 3476** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3477** 3478** See also: [sqlite3_bind_parameter_count()], 3479** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3480*/ 3481int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3482int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3483 void(*)(void*)); 3484int sqlite3_bind_double(sqlite3_stmt*, int, double); 3485int sqlite3_bind_int(sqlite3_stmt*, int, int); 3486int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3487int sqlite3_bind_null(sqlite3_stmt*, int); 3488int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3489int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3490int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3491 void(*)(void*), unsigned char encoding); 3492int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3493int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3494 3495/* 3496** CAPI3REF: Number Of SQL Parameters 3497** 3498** ^This routine can be used to find the number of [SQL parameters] 3499** in a [prepared statement]. SQL parameters are tokens of the 3500** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3501** placeholders for values that are [sqlite3_bind_blob | bound] 3502** to the parameters at a later time. 3503** 3504** ^(This routine actually returns the index of the largest (rightmost) 3505** parameter. For all forms except ?NNN, this will correspond to the 3506** number of unique parameters. If parameters of the ?NNN form are used, 3507** there may be gaps in the list.)^ 3508** 3509** See also: [sqlite3_bind_blob|sqlite3_bind()], 3510** [sqlite3_bind_parameter_name()], and 3511** [sqlite3_bind_parameter_index()]. 3512*/ 3513int sqlite3_bind_parameter_count(sqlite3_stmt*); 3514 3515/* 3516** CAPI3REF: Name Of A Host Parameter 3517** 3518** ^The sqlite3_bind_parameter_name(P,N) interface returns 3519** the name of the N-th [SQL parameter] in the [prepared statement] P. 3520** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3521** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3522** respectively. 3523** In other words, the initial ":" or "$" or "@" or "?" 3524** is included as part of the name.)^ 3525** ^Parameters of the form "?" without a following integer have no name 3526** and are referred to as "nameless" or "anonymous parameters". 3527** 3528** ^The first host parameter has an index of 1, not 0. 3529** 3530** ^If the value N is out of range or if the N-th parameter is 3531** nameless, then NULL is returned. ^The returned string is 3532** always in UTF-8 encoding even if the named parameter was 3533** originally specified as UTF-16 in [sqlite3_prepare16()] or 3534** [sqlite3_prepare16_v2()]. 3535** 3536** See also: [sqlite3_bind_blob|sqlite3_bind()], 3537** [sqlite3_bind_parameter_count()], and 3538** [sqlite3_bind_parameter_index()]. 3539*/ 3540const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3541 3542/* 3543** CAPI3REF: Index Of A Parameter With A Given Name 3544** 3545** ^Return the index of an SQL parameter given its name. ^The 3546** index value returned is suitable for use as the second 3547** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3548** is returned if no matching parameter is found. ^The parameter 3549** name must be given in UTF-8 even if the original statement 3550** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3551** 3552** See also: [sqlite3_bind_blob|sqlite3_bind()], 3553** [sqlite3_bind_parameter_count()], and 3554** [sqlite3_bind_parameter_index()]. 3555*/ 3556int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3557 3558/* 3559** CAPI3REF: Reset All Bindings On A Prepared Statement 3560** 3561** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3562** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3563** ^Use this routine to reset all host parameters to NULL. 3564*/ 3565int sqlite3_clear_bindings(sqlite3_stmt*); 3566 3567/* 3568** CAPI3REF: Number Of Columns In A Result Set 3569** 3570** ^Return the number of columns in the result set returned by the 3571** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3572** statement that does not return data (for example an [UPDATE]). 3573** 3574** See also: [sqlite3_data_count()] 3575*/ 3576int sqlite3_column_count(sqlite3_stmt *pStmt); 3577 3578/* 3579** CAPI3REF: Column Names In A Result Set 3580** 3581** ^These routines return the name assigned to a particular column 3582** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3583** interface returns a pointer to a zero-terminated UTF-8 string 3584** and sqlite3_column_name16() returns a pointer to a zero-terminated 3585** UTF-16 string. ^The first parameter is the [prepared statement] 3586** that implements the [SELECT] statement. ^The second parameter is the 3587** column number. ^The leftmost column is number 0. 3588** 3589** ^The returned string pointer is valid until either the [prepared statement] 3590** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3591** reprepared by the first call to [sqlite3_step()] for a particular run 3592** or until the next call to 3593** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3594** 3595** ^If sqlite3_malloc() fails during the processing of either routine 3596** (for example during a conversion from UTF-8 to UTF-16) then a 3597** NULL pointer is returned. 3598** 3599** ^The name of a result column is the value of the "AS" clause for 3600** that column, if there is an AS clause. If there is no AS clause 3601** then the name of the column is unspecified and may change from 3602** one release of SQLite to the next. 3603*/ 3604const char *sqlite3_column_name(sqlite3_stmt*, int N); 3605const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3606 3607/* 3608** CAPI3REF: Source Of Data In A Query Result 3609** 3610** ^These routines provide a means to determine the database, table, and 3611** table column that is the origin of a particular result column in 3612** [SELECT] statement. 3613** ^The name of the database or table or column can be returned as 3614** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3615** the database name, the _table_ routines return the table name, and 3616** the origin_ routines return the column name. 3617** ^The returned string is valid until the [prepared statement] is destroyed 3618** using [sqlite3_finalize()] or until the statement is automatically 3619** reprepared by the first call to [sqlite3_step()] for a particular run 3620** or until the same information is requested 3621** again in a different encoding. 3622** 3623** ^The names returned are the original un-aliased names of the 3624** database, table, and column. 3625** 3626** ^The first argument to these interfaces is a [prepared statement]. 3627** ^These functions return information about the Nth result column returned by 3628** the statement, where N is the second function argument. 3629** ^The left-most column is column 0 for these routines. 3630** 3631** ^If the Nth column returned by the statement is an expression or 3632** subquery and is not a column value, then all of these functions return 3633** NULL. ^These routine might also return NULL if a memory allocation error 3634** occurs. ^Otherwise, they return the name of the attached database, table, 3635** or column that query result column was extracted from. 3636** 3637** ^As with all other SQLite APIs, those whose names end with "16" return 3638** UTF-16 encoded strings and the other functions return UTF-8. 3639** 3640** ^These APIs are only available if the library was compiled with the 3641** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3642** 3643** If two or more threads call one or more of these routines against the same 3644** prepared statement and column at the same time then the results are 3645** undefined. 3646** 3647** If two or more threads call one or more 3648** [sqlite3_column_database_name | column metadata interfaces] 3649** for the same [prepared statement] and result column 3650** at the same time then the results are undefined. 3651*/ 3652const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3653const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3654const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3655const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3656const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3657const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3658 3659/* 3660** CAPI3REF: Declared Datatype Of A Query Result 3661** 3662** ^(The first parameter is a [prepared statement]. 3663** If this statement is a [SELECT] statement and the Nth column of the 3664** returned result set of that [SELECT] is a table column (not an 3665** expression or subquery) then the declared type of the table 3666** column is returned.)^ ^If the Nth column of the result set is an 3667** expression or subquery, then a NULL pointer is returned. 3668** ^The returned string is always UTF-8 encoded. 3669** 3670** ^(For example, given the database schema: 3671** 3672** CREATE TABLE t1(c1 VARIANT); 3673** 3674** and the following statement to be compiled: 3675** 3676** SELECT c1 + 1, c1 FROM t1; 3677** 3678** this routine would return the string "VARIANT" for the second result 3679** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3680** 3681** ^SQLite uses dynamic run-time typing. ^So just because a column 3682** is declared to contain a particular type does not mean that the 3683** data stored in that column is of the declared type. SQLite is 3684** strongly typed, but the typing is dynamic not static. ^Type 3685** is associated with individual values, not with the containers 3686** used to hold those values. 3687*/ 3688const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3689const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3690 3691/* 3692** CAPI3REF: Evaluate An SQL Statement 3693** 3694** After a [prepared statement] has been prepared using either 3695** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3696** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3697** must be called one or more times to evaluate the statement. 3698** 3699** The details of the behavior of the sqlite3_step() interface depend 3700** on whether the statement was prepared using the newer "v2" interface 3701** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3702** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3703** new "v2" interface is recommended for new applications but the legacy 3704** interface will continue to be supported. 3705** 3706** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3707** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3708** ^With the "v2" interface, any of the other [result codes] or 3709** [extended result codes] might be returned as well. 3710** 3711** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3712** database locks it needs to do its job. ^If the statement is a [COMMIT] 3713** or occurs outside of an explicit transaction, then you can retry the 3714** statement. If the statement is not a [COMMIT] and occurs within an 3715** explicit transaction then you should rollback the transaction before 3716** continuing. 3717** 3718** ^[SQLITE_DONE] means that the statement has finished executing 3719** successfully. sqlite3_step() should not be called again on this virtual 3720** machine without first calling [sqlite3_reset()] to reset the virtual 3721** machine back to its initial state. 3722** 3723** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3724** is returned each time a new row of data is ready for processing by the 3725** caller. The values may be accessed using the [column access functions]. 3726** sqlite3_step() is called again to retrieve the next row of data. 3727** 3728** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3729** violation) has occurred. sqlite3_step() should not be called again on 3730** the VM. More information may be found by calling [sqlite3_errmsg()]. 3731** ^With the legacy interface, a more specific error code (for example, 3732** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3733** can be obtained by calling [sqlite3_reset()] on the 3734** [prepared statement]. ^In the "v2" interface, 3735** the more specific error code is returned directly by sqlite3_step(). 3736** 3737** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3738** Perhaps it was called on a [prepared statement] that has 3739** already been [sqlite3_finalize | finalized] or on one that had 3740** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3741** be the case that the same database connection is being used by two or 3742** more threads at the same moment in time. 3743** 3744** For all versions of SQLite up to and including 3.6.23.1, a call to 3745** [sqlite3_reset()] was required after sqlite3_step() returned anything 3746** other than [SQLITE_ROW] before any subsequent invocation of 3747** sqlite3_step(). Failure to reset the prepared statement using 3748** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3749** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3750** calling [sqlite3_reset()] automatically in this circumstance rather 3751** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3752** break because any application that ever receives an SQLITE_MISUSE error 3753** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3754** can be used to restore the legacy behavior. 3755** 3756** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3757** API always returns a generic error code, [SQLITE_ERROR], following any 3758** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3759** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3760** specific [error codes] that better describes the error. 3761** We admit that this is a goofy design. The problem has been fixed 3762** with the "v2" interface. If you prepare all of your SQL statements 3763** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3764** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3765** then the more specific [error codes] are returned directly 3766** by sqlite3_step(). The use of the "v2" interface is recommended. 3767*/ 3768int sqlite3_step(sqlite3_stmt*); 3769 3770/* 3771** CAPI3REF: Number of columns in a result set 3772** 3773** ^The sqlite3_data_count(P) interface returns the number of columns in the 3774** current row of the result set of [prepared statement] P. 3775** ^If prepared statement P does not have results ready to return 3776** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3777** interfaces) then sqlite3_data_count(P) returns 0. 3778** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3779** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 3780** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 3781** will return non-zero if previous call to [sqlite3_step](P) returned 3782** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 3783** where it always returns zero since each step of that multi-step 3784** pragma returns 0 columns of data. 3785** 3786** See also: [sqlite3_column_count()] 3787*/ 3788int sqlite3_data_count(sqlite3_stmt *pStmt); 3789 3790/* 3791** CAPI3REF: Fundamental Datatypes 3792** KEYWORDS: SQLITE_TEXT 3793** 3794** ^(Every value in SQLite has one of five fundamental datatypes: 3795** 3796** <ul> 3797** <li> 64-bit signed integer 3798** <li> 64-bit IEEE floating point number 3799** <li> string 3800** <li> BLOB 3801** <li> NULL 3802** </ul>)^ 3803** 3804** These constants are codes for each of those types. 3805** 3806** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3807** for a completely different meaning. Software that links against both 3808** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3809** SQLITE_TEXT. 3810*/ 3811#define SQLITE_INTEGER 1 3812#define SQLITE_FLOAT 2 3813#define SQLITE_BLOB 4 3814#define SQLITE_NULL 5 3815#ifdef SQLITE_TEXT 3816# undef SQLITE_TEXT 3817#else 3818# define SQLITE_TEXT 3 3819#endif 3820#define SQLITE3_TEXT 3 3821 3822/* 3823** CAPI3REF: Result Values From A Query 3824** KEYWORDS: {column access functions} 3825** 3826** These routines form the "result set" interface. 3827** 3828** ^These routines return information about a single column of the current 3829** result row of a query. ^In every case the first argument is a pointer 3830** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3831** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3832** and the second argument is the index of the column for which information 3833** should be returned. ^The leftmost column of the result set has the index 0. 3834** ^The number of columns in the result can be determined using 3835** [sqlite3_column_count()]. 3836** 3837** If the SQL statement does not currently point to a valid row, or if the 3838** column index is out of range, the result is undefined. 3839** These routines may only be called when the most recent call to 3840** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3841** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3842** If any of these routines are called after [sqlite3_reset()] or 3843** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3844** something other than [SQLITE_ROW], the results are undefined. 3845** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3846** are called from a different thread while any of these routines 3847** are pending, then the results are undefined. 3848** 3849** ^The sqlite3_column_type() routine returns the 3850** [SQLITE_INTEGER | datatype code] for the initial data type 3851** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3852** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3853** returned by sqlite3_column_type() is only meaningful if no type 3854** conversions have occurred as described below. After a type conversion, 3855** the value returned by sqlite3_column_type() is undefined. Future 3856** versions of SQLite may change the behavior of sqlite3_column_type() 3857** following a type conversion. 3858** 3859** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3860** routine returns the number of bytes in that BLOB or string. 3861** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3862** the string to UTF-8 and then returns the number of bytes. 3863** ^If the result is a numeric value then sqlite3_column_bytes() uses 3864** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3865** the number of bytes in that string. 3866** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3867** 3868** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3869** routine returns the number of bytes in that BLOB or string. 3870** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3871** the string to UTF-16 and then returns the number of bytes. 3872** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3873** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3874** the number of bytes in that string. 3875** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3876** 3877** ^The values returned by [sqlite3_column_bytes()] and 3878** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3879** of the string. ^For clarity: the values returned by 3880** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3881** bytes in the string, not the number of characters. 3882** 3883** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3884** even empty strings, are always zero-terminated. ^The return 3885** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3886** 3887** ^The object returned by [sqlite3_column_value()] is an 3888** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3889** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3890** If the [unprotected sqlite3_value] object returned by 3891** [sqlite3_column_value()] is used in any other way, including calls 3892** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3893** or [sqlite3_value_bytes()], then the behavior is undefined. 3894** 3895** These routines attempt to convert the value where appropriate. ^For 3896** example, if the internal representation is FLOAT and a text result 3897** is requested, [sqlite3_snprintf()] is used internally to perform the 3898** conversion automatically. ^(The following table details the conversions 3899** that are applied: 3900** 3901** <blockquote> 3902** <table border="1"> 3903** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3904** 3905** <tr><td> NULL <td> INTEGER <td> Result is 0 3906** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3907** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 3908** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 3909** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3910** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3911** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3912** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 3913** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3914** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 3915** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 3916** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 3917** <tr><td> TEXT <td> BLOB <td> No change 3918** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 3919** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 3920** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3921** </table> 3922** </blockquote>)^ 3923** 3924** The table above makes reference to standard C library functions atoi() 3925** and atof(). SQLite does not really use these functions. It has its 3926** own equivalent internal routines. The atoi() and atof() names are 3927** used in the table for brevity and because they are familiar to most 3928** C programmers. 3929** 3930** Note that when type conversions occur, pointers returned by prior 3931** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3932** sqlite3_column_text16() may be invalidated. 3933** Type conversions and pointer invalidations might occur 3934** in the following cases: 3935** 3936** <ul> 3937** <li> The initial content is a BLOB and sqlite3_column_text() or 3938** sqlite3_column_text16() is called. A zero-terminator might 3939** need to be added to the string.</li> 3940** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3941** sqlite3_column_text16() is called. The content must be converted 3942** to UTF-16.</li> 3943** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3944** sqlite3_column_text() is called. The content must be converted 3945** to UTF-8.</li> 3946** </ul> 3947** 3948** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3949** not invalidate a prior pointer, though of course the content of the buffer 3950** that the prior pointer references will have been modified. Other kinds 3951** of conversion are done in place when it is possible, but sometimes they 3952** are not possible and in those cases prior pointers are invalidated. 3953** 3954** The safest and easiest to remember policy is to invoke these routines 3955** in one of the following ways: 3956** 3957** <ul> 3958** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3959** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3960** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3961** </ul> 3962** 3963** In other words, you should call sqlite3_column_text(), 3964** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3965** into the desired format, then invoke sqlite3_column_bytes() or 3966** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3967** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3968** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3969** with calls to sqlite3_column_bytes(). 3970** 3971** ^The pointers returned are valid until a type conversion occurs as 3972** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3973** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3974** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3975** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3976** [sqlite3_free()]. 3977** 3978** ^(If a memory allocation error occurs during the evaluation of any 3979** of these routines, a default value is returned. The default value 3980** is either the integer 0, the floating point number 0.0, or a NULL 3981** pointer. Subsequent calls to [sqlite3_errcode()] will return 3982** [SQLITE_NOMEM].)^ 3983*/ 3984const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3985int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3986int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3987double sqlite3_column_double(sqlite3_stmt*, int iCol); 3988int sqlite3_column_int(sqlite3_stmt*, int iCol); 3989sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3990const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3991const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3992int sqlite3_column_type(sqlite3_stmt*, int iCol); 3993sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3994 3995/* 3996** CAPI3REF: Destroy A Prepared Statement Object 3997** 3998** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3999** ^If the most recent evaluation of the statement encountered no errors 4000** or if the statement is never been evaluated, then sqlite3_finalize() returns 4001** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4002** sqlite3_finalize(S) returns the appropriate [error code] or 4003** [extended error code]. 4004** 4005** ^The sqlite3_finalize(S) routine can be called at any point during 4006** the life cycle of [prepared statement] S: 4007** before statement S is ever evaluated, after 4008** one or more calls to [sqlite3_reset()], or after any call 4009** to [sqlite3_step()] regardless of whether or not the statement has 4010** completed execution. 4011** 4012** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4013** 4014** The application must finalize every [prepared statement] in order to avoid 4015** resource leaks. It is a grievous error for the application to try to use 4016** a prepared statement after it has been finalized. Any use of a prepared 4017** statement after it has been finalized can result in undefined and 4018** undesirable behavior such as segfaults and heap corruption. 4019*/ 4020int sqlite3_finalize(sqlite3_stmt *pStmt); 4021 4022/* 4023** CAPI3REF: Reset A Prepared Statement Object 4024** 4025** The sqlite3_reset() function is called to reset a [prepared statement] 4026** object back to its initial state, ready to be re-executed. 4027** ^Any SQL statement variables that had values bound to them using 4028** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4029** Use [sqlite3_clear_bindings()] to reset the bindings. 4030** 4031** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4032** back to the beginning of its program. 4033** 4034** ^If the most recent call to [sqlite3_step(S)] for the 4035** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4036** or if [sqlite3_step(S)] has never before been called on S, 4037** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4038** 4039** ^If the most recent call to [sqlite3_step(S)] for the 4040** [prepared statement] S indicated an error, then 4041** [sqlite3_reset(S)] returns an appropriate [error code]. 4042** 4043** ^The [sqlite3_reset(S)] interface does not change the values 4044** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4045*/ 4046int sqlite3_reset(sqlite3_stmt *pStmt); 4047 4048/* 4049** CAPI3REF: Create Or Redefine SQL Functions 4050** KEYWORDS: {function creation routines} 4051** KEYWORDS: {application-defined SQL function} 4052** KEYWORDS: {application-defined SQL functions} 4053** 4054** ^These functions (collectively known as "function creation routines") 4055** are used to add SQL functions or aggregates or to redefine the behavior 4056** of existing SQL functions or aggregates. The only differences between 4057** these routines are the text encoding expected for 4058** the second parameter (the name of the function being created) 4059** and the presence or absence of a destructor callback for 4060** the application data pointer. 4061** 4062** ^The first parameter is the [database connection] to which the SQL 4063** function is to be added. ^If an application uses more than one database 4064** connection then application-defined SQL functions must be added 4065** to each database connection separately. 4066** 4067** ^The second parameter is the name of the SQL function to be created or 4068** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4069** representation, exclusive of the zero-terminator. ^Note that the name 4070** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4071** ^Any attempt to create a function with a longer name 4072** will result in [SQLITE_MISUSE] being returned. 4073** 4074** ^The third parameter (nArg) 4075** is the number of arguments that the SQL function or 4076** aggregate takes. ^If this parameter is -1, then the SQL function or 4077** aggregate may take any number of arguments between 0 and the limit 4078** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4079** parameter is less than -1 or greater than 127 then the behavior is 4080** undefined. 4081** 4082** ^The fourth parameter, eTextRep, specifies what 4083** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4084** its parameters. The application should set this parameter to 4085** [SQLITE_UTF16LE] if the function implementation invokes 4086** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4087** implementation invokes [sqlite3_value_text16be()] on an input, or 4088** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4089** otherwise. ^The same SQL function may be registered multiple times using 4090** different preferred text encodings, with different implementations for 4091** each encoding. 4092** ^When multiple implementations of the same function are available, SQLite 4093** will pick the one that involves the least amount of data conversion. 4094** 4095** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4096** to signal that the function will always return the same result given 4097** the same inputs within a single SQL statement. Most SQL functions are 4098** deterministic. The built-in [random()] SQL function is an example of a 4099** function that is not deterministic. The SQLite query planner is able to 4100** perform additional optimizations on deterministic functions, so use 4101** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4102** 4103** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4104** function can gain access to this pointer using [sqlite3_user_data()].)^ 4105** 4106** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4107** pointers to C-language functions that implement the SQL function or 4108** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4109** callback only; NULL pointers must be passed as the xStep and xFinal 4110** parameters. ^An aggregate SQL function requires an implementation of xStep 4111** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4112** SQL function or aggregate, pass NULL pointers for all three function 4113** callbacks. 4114** 4115** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4116** then it is destructor for the application data pointer. 4117** The destructor is invoked when the function is deleted, either by being 4118** overloaded or when the database connection closes.)^ 4119** ^The destructor is also invoked if the call to 4120** sqlite3_create_function_v2() fails. 4121** ^When the destructor callback of the tenth parameter is invoked, it 4122** is passed a single argument which is a copy of the application data 4123** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4124** 4125** ^It is permitted to register multiple implementations of the same 4126** functions with the same name but with either differing numbers of 4127** arguments or differing preferred text encodings. ^SQLite will use 4128** the implementation that most closely matches the way in which the 4129** SQL function is used. ^A function implementation with a non-negative 4130** nArg parameter is a better match than a function implementation with 4131** a negative nArg. ^A function where the preferred text encoding 4132** matches the database encoding is a better 4133** match than a function where the encoding is different. 4134** ^A function where the encoding difference is between UTF16le and UTF16be 4135** is a closer match than a function where the encoding difference is 4136** between UTF8 and UTF16. 4137** 4138** ^Built-in functions may be overloaded by new application-defined functions. 4139** 4140** ^An application-defined function is permitted to call other 4141** SQLite interfaces. However, such calls must not 4142** close the database connection nor finalize or reset the prepared 4143** statement in which the function is running. 4144*/ 4145int sqlite3_create_function( 4146 sqlite3 *db, 4147 const char *zFunctionName, 4148 int nArg, 4149 int eTextRep, 4150 void *pApp, 4151 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4152 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4153 void (*xFinal)(sqlite3_context*) 4154); 4155int sqlite3_create_function16( 4156 sqlite3 *db, 4157 const void *zFunctionName, 4158 int nArg, 4159 int eTextRep, 4160 void *pApp, 4161 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4162 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4163 void (*xFinal)(sqlite3_context*) 4164); 4165int sqlite3_create_function_v2( 4166 sqlite3 *db, 4167 const char *zFunctionName, 4168 int nArg, 4169 int eTextRep, 4170 void *pApp, 4171 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4172 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4173 void (*xFinal)(sqlite3_context*), 4174 void(*xDestroy)(void*) 4175); 4176 4177/* 4178** CAPI3REF: Text Encodings 4179** 4180** These constant define integer codes that represent the various 4181** text encodings supported by SQLite. 4182*/ 4183#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4184#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4185#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4186#define SQLITE_UTF16 4 /* Use native byte order */ 4187#define SQLITE_ANY 5 /* Deprecated */ 4188#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4189 4190/* 4191** CAPI3REF: Function Flags 4192** 4193** These constants may be ORed together with the 4194** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4195** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4196** [sqlite3_create_function_v2()]. 4197*/ 4198#define SQLITE_DETERMINISTIC 0x800 4199 4200/* 4201** CAPI3REF: Deprecated Functions 4202** DEPRECATED 4203** 4204** These functions are [deprecated]. In order to maintain 4205** backwards compatibility with older code, these functions continue 4206** to be supported. However, new applications should avoid 4207** the use of these functions. To help encourage people to avoid 4208** using these functions, we are not going to tell you what they do. 4209*/ 4210#ifndef SQLITE_OMIT_DEPRECATED 4211SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4212SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4213SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4214SQLITE_DEPRECATED int sqlite3_global_recover(void); 4215SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4216SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4217 void*,sqlite3_int64); 4218#endif 4219 4220/* 4221** CAPI3REF: Obtaining SQL Function Parameter Values 4222** 4223** The C-language implementation of SQL functions and aggregates uses 4224** this set of interface routines to access the parameter values on 4225** the function or aggregate. 4226** 4227** The xFunc (for scalar functions) or xStep (for aggregates) parameters 4228** to [sqlite3_create_function()] and [sqlite3_create_function16()] 4229** define callbacks that implement the SQL functions and aggregates. 4230** The 3rd parameter to these callbacks is an array of pointers to 4231** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 4232** each parameter to the SQL function. These routines are used to 4233** extract values from the [sqlite3_value] objects. 4234** 4235** These routines work only with [protected sqlite3_value] objects. 4236** Any attempt to use these routines on an [unprotected sqlite3_value] 4237** object results in undefined behavior. 4238** 4239** ^These routines work just like the corresponding [column access functions] 4240** except that these routines take a single [protected sqlite3_value] object 4241** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4242** 4243** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4244** in the native byte-order of the host machine. ^The 4245** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4246** extract UTF-16 strings as big-endian and little-endian respectively. 4247** 4248** ^(The sqlite3_value_numeric_type() interface attempts to apply 4249** numeric affinity to the value. This means that an attempt is 4250** made to convert the value to an integer or floating point. If 4251** such a conversion is possible without loss of information (in other 4252** words, if the value is a string that looks like a number) 4253** then the conversion is performed. Otherwise no conversion occurs. 4254** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4255** 4256** Please pay particular attention to the fact that the pointer returned 4257** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4258** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4259** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4260** or [sqlite3_value_text16()]. 4261** 4262** These routines must be called from the same thread as 4263** the SQL function that supplied the [sqlite3_value*] parameters. 4264*/ 4265const void *sqlite3_value_blob(sqlite3_value*); 4266int sqlite3_value_bytes(sqlite3_value*); 4267int sqlite3_value_bytes16(sqlite3_value*); 4268double sqlite3_value_double(sqlite3_value*); 4269int sqlite3_value_int(sqlite3_value*); 4270sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4271const unsigned char *sqlite3_value_text(sqlite3_value*); 4272const void *sqlite3_value_text16(sqlite3_value*); 4273const void *sqlite3_value_text16le(sqlite3_value*); 4274const void *sqlite3_value_text16be(sqlite3_value*); 4275int sqlite3_value_type(sqlite3_value*); 4276int sqlite3_value_numeric_type(sqlite3_value*); 4277 4278/* 4279** CAPI3REF: Obtain Aggregate Function Context 4280** 4281** Implementations of aggregate SQL functions use this 4282** routine to allocate memory for storing their state. 4283** 4284** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4285** for a particular aggregate function, SQLite 4286** allocates N of memory, zeroes out that memory, and returns a pointer 4287** to the new memory. ^On second and subsequent calls to 4288** sqlite3_aggregate_context() for the same aggregate function instance, 4289** the same buffer is returned. Sqlite3_aggregate_context() is normally 4290** called once for each invocation of the xStep callback and then one 4291** last time when the xFinal callback is invoked. ^(When no rows match 4292** an aggregate query, the xStep() callback of the aggregate function 4293** implementation is never called and xFinal() is called exactly once. 4294** In those cases, sqlite3_aggregate_context() might be called for the 4295** first time from within xFinal().)^ 4296** 4297** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4298** when first called if N is less than or equal to zero or if a memory 4299** allocate error occurs. 4300** 4301** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4302** determined by the N parameter on first successful call. Changing the 4303** value of N in subsequent call to sqlite3_aggregate_context() within 4304** the same aggregate function instance will not resize the memory 4305** allocation.)^ Within the xFinal callback, it is customary to set 4306** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4307** pointless memory allocations occur. 4308** 4309** ^SQLite automatically frees the memory allocated by 4310** sqlite3_aggregate_context() when the aggregate query concludes. 4311** 4312** The first parameter must be a copy of the 4313** [sqlite3_context | SQL function context] that is the first parameter 4314** to the xStep or xFinal callback routine that implements the aggregate 4315** function. 4316** 4317** This routine must be called from the same thread in which 4318** the aggregate SQL function is running. 4319*/ 4320void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4321 4322/* 4323** CAPI3REF: User Data For Functions 4324** 4325** ^The sqlite3_user_data() interface returns a copy of 4326** the pointer that was the pUserData parameter (the 5th parameter) 4327** of the [sqlite3_create_function()] 4328** and [sqlite3_create_function16()] routines that originally 4329** registered the application defined function. 4330** 4331** This routine must be called from the same thread in which 4332** the application-defined function is running. 4333*/ 4334void *sqlite3_user_data(sqlite3_context*); 4335 4336/* 4337** CAPI3REF: Database Connection For Functions 4338** 4339** ^The sqlite3_context_db_handle() interface returns a copy of 4340** the pointer to the [database connection] (the 1st parameter) 4341** of the [sqlite3_create_function()] 4342** and [sqlite3_create_function16()] routines that originally 4343** registered the application defined function. 4344*/ 4345sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4346 4347/* 4348** CAPI3REF: Function Auxiliary Data 4349** 4350** These functions may be used by (non-aggregate) SQL functions to 4351** associate metadata with argument values. If the same value is passed to 4352** multiple invocations of the same SQL function during query execution, under 4353** some circumstances the associated metadata may be preserved. An example 4354** of where this might be useful is in a regular-expression matching 4355** function. The compiled version of the regular expression can be stored as 4356** metadata associated with the pattern string. 4357** Then as long as the pattern string remains the same, 4358** the compiled regular expression can be reused on multiple 4359** invocations of the same function. 4360** 4361** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4362** associated by the sqlite3_set_auxdata() function with the Nth argument 4363** value to the application-defined function. ^If there is no metadata 4364** associated with the function argument, this sqlite3_get_auxdata() interface 4365** returns a NULL pointer. 4366** 4367** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4368** argument of the application-defined function. ^Subsequent 4369** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4370** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4371** NULL if the metadata has been discarded. 4372** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4373** SQLite will invoke the destructor function X with parameter P exactly 4374** once, when the metadata is discarded. 4375** SQLite is free to discard the metadata at any time, including: <ul> 4376** <li> when the corresponding function parameter changes, or 4377** <li> when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4378** SQL statement, or 4379** <li> when sqlite3_set_auxdata() is invoked again on the same parameter, or 4380** <li> during the original sqlite3_set_auxdata() call when a memory 4381** allocation error occurs. </ul>)^ 4382** 4383** Note the last bullet in particular. The destructor X in 4384** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 4385** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 4386** should be called near the end of the function implementation and the 4387** function implementation should not make any use of P after 4388** sqlite3_set_auxdata() has been called. 4389** 4390** ^(In practice, metadata is preserved between function calls for 4391** function parameters that are compile-time constants, including literal 4392** values and [parameters] and expressions composed from the same.)^ 4393** 4394** These routines must be called from the same thread in which 4395** the SQL function is running. 4396*/ 4397void *sqlite3_get_auxdata(sqlite3_context*, int N); 4398void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4399 4400 4401/* 4402** CAPI3REF: Constants Defining Special Destructor Behavior 4403** 4404** These are special values for the destructor that is passed in as the 4405** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4406** argument is SQLITE_STATIC, it means that the content pointer is constant 4407** and will never change. It does not need to be destroyed. ^The 4408** SQLITE_TRANSIENT value means that the content will likely change in 4409** the near future and that SQLite should make its own private copy of 4410** the content before returning. 4411** 4412** The typedef is necessary to work around problems in certain 4413** C++ compilers. 4414*/ 4415typedef void (*sqlite3_destructor_type)(void*); 4416#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4417#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4418 4419/* 4420** CAPI3REF: Setting The Result Of An SQL Function 4421** 4422** These routines are used by the xFunc or xFinal callbacks that 4423** implement SQL functions and aggregates. See 4424** [sqlite3_create_function()] and [sqlite3_create_function16()] 4425** for additional information. 4426** 4427** These functions work very much like the [parameter binding] family of 4428** functions used to bind values to host parameters in prepared statements. 4429** Refer to the [SQL parameter] documentation for additional information. 4430** 4431** ^The sqlite3_result_blob() interface sets the result from 4432** an application-defined function to be the BLOB whose content is pointed 4433** to by the second parameter and which is N bytes long where N is the 4434** third parameter. 4435** 4436** ^The sqlite3_result_zeroblob() interfaces set the result of 4437** the application-defined function to be a BLOB containing all zero 4438** bytes and N bytes in size, where N is the value of the 2nd parameter. 4439** 4440** ^The sqlite3_result_double() interface sets the result from 4441** an application-defined function to be a floating point value specified 4442** by its 2nd argument. 4443** 4444** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4445** cause the implemented SQL function to throw an exception. 4446** ^SQLite uses the string pointed to by the 4447** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4448** as the text of an error message. ^SQLite interprets the error 4449** message string from sqlite3_result_error() as UTF-8. ^SQLite 4450** interprets the string from sqlite3_result_error16() as UTF-16 in native 4451** byte order. ^If the third parameter to sqlite3_result_error() 4452** or sqlite3_result_error16() is negative then SQLite takes as the error 4453** message all text up through the first zero character. 4454** ^If the third parameter to sqlite3_result_error() or 4455** sqlite3_result_error16() is non-negative then SQLite takes that many 4456** bytes (not characters) from the 2nd parameter as the error message. 4457** ^The sqlite3_result_error() and sqlite3_result_error16() 4458** routines make a private copy of the error message text before 4459** they return. Hence, the calling function can deallocate or 4460** modify the text after they return without harm. 4461** ^The sqlite3_result_error_code() function changes the error code 4462** returned by SQLite as a result of an error in a function. ^By default, 4463** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4464** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4465** 4466** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 4467** error indicating that a string or BLOB is too long to represent. 4468** 4469** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 4470** error indicating that a memory allocation failed. 4471** 4472** ^The sqlite3_result_int() interface sets the return value 4473** of the application-defined function to be the 32-bit signed integer 4474** value given in the 2nd argument. 4475** ^The sqlite3_result_int64() interface sets the return value 4476** of the application-defined function to be the 64-bit signed integer 4477** value given in the 2nd argument. 4478** 4479** ^The sqlite3_result_null() interface sets the return value 4480** of the application-defined function to be NULL. 4481** 4482** ^The sqlite3_result_text(), sqlite3_result_text16(), 4483** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4484** set the return value of the application-defined function to be 4485** a text string which is represented as UTF-8, UTF-16 native byte order, 4486** UTF-16 little endian, or UTF-16 big endian, respectively. 4487** ^The sqlite3_result_text64() interface sets the return value of an 4488** application-defined function to be a text string in an encoding 4489** specified by the fifth (and last) parameter, which must be one 4490** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 4491** ^SQLite takes the text result from the application from 4492** the 2nd parameter of the sqlite3_result_text* interfaces. 4493** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4494** is negative, then SQLite takes result text from the 2nd parameter 4495** through the first zero character. 4496** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4497** is non-negative, then as many bytes (not characters) of the text 4498** pointed to by the 2nd parameter are taken as the application-defined 4499** function result. If the 3rd parameter is non-negative, then it 4500** must be the byte offset into the string where the NUL terminator would 4501** appear if the string where NUL terminated. If any NUL characters occur 4502** in the string at a byte offset that is less than the value of the 3rd 4503** parameter, then the resulting string will contain embedded NULs and the 4504** result of expressions operating on strings with embedded NULs is undefined. 4505** ^If the 4th parameter to the sqlite3_result_text* interfaces 4506** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4507** function as the destructor on the text or BLOB result when it has 4508** finished using that result. 4509** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4510** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4511** assumes that the text or BLOB result is in constant space and does not 4512** copy the content of the parameter nor call a destructor on the content 4513** when it has finished using that result. 4514** ^If the 4th parameter to the sqlite3_result_text* interfaces 4515** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4516** then SQLite makes a copy of the result into space obtained from 4517** from [sqlite3_malloc()] before it returns. 4518** 4519** ^The sqlite3_result_value() interface sets the result of 4520** the application-defined function to be a copy the 4521** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4522** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4523** so that the [sqlite3_value] specified in the parameter may change or 4524** be deallocated after sqlite3_result_value() returns without harm. 4525** ^A [protected sqlite3_value] object may always be used where an 4526** [unprotected sqlite3_value] object is required, so either 4527** kind of [sqlite3_value] object can be used with this interface. 4528** 4529** If these routines are called from within the different thread 4530** than the one containing the application-defined function that received 4531** the [sqlite3_context] pointer, the results are undefined. 4532*/ 4533void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4534void sqlite3_result_blob64(sqlite3_context*,const void*, 4535 sqlite3_uint64,void(*)(void*)); 4536void sqlite3_result_double(sqlite3_context*, double); 4537void sqlite3_result_error(sqlite3_context*, const char*, int); 4538void sqlite3_result_error16(sqlite3_context*, const void*, int); 4539void sqlite3_result_error_toobig(sqlite3_context*); 4540void sqlite3_result_error_nomem(sqlite3_context*); 4541void sqlite3_result_error_code(sqlite3_context*, int); 4542void sqlite3_result_int(sqlite3_context*, int); 4543void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4544void sqlite3_result_null(sqlite3_context*); 4545void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4546void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 4547 void(*)(void*), unsigned char encoding); 4548void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4549void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4550void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4551void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4552void sqlite3_result_zeroblob(sqlite3_context*, int n); 4553 4554/* 4555** CAPI3REF: Define New Collating Sequences 4556** 4557** ^These functions add, remove, or modify a [collation] associated 4558** with the [database connection] specified as the first argument. 4559** 4560** ^The name of the collation is a UTF-8 string 4561** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4562** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4563** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4564** considered to be the same name. 4565** 4566** ^(The third argument (eTextRep) must be one of the constants: 4567** <ul> 4568** <li> [SQLITE_UTF8], 4569** <li> [SQLITE_UTF16LE], 4570** <li> [SQLITE_UTF16BE], 4571** <li> [SQLITE_UTF16], or 4572** <li> [SQLITE_UTF16_ALIGNED]. 4573** </ul>)^ 4574** ^The eTextRep argument determines the encoding of strings passed 4575** to the collating function callback, xCallback. 4576** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4577** force strings to be UTF16 with native byte order. 4578** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4579** on an even byte address. 4580** 4581** ^The fourth argument, pArg, is an application data pointer that is passed 4582** through as the first argument to the collating function callback. 4583** 4584** ^The fifth argument, xCallback, is a pointer to the collating function. 4585** ^Multiple collating functions can be registered using the same name but 4586** with different eTextRep parameters and SQLite will use whichever 4587** function requires the least amount of data transformation. 4588** ^If the xCallback argument is NULL then the collating function is 4589** deleted. ^When all collating functions having the same name are deleted, 4590** that collation is no longer usable. 4591** 4592** ^The collating function callback is invoked with a copy of the pArg 4593** application data pointer and with two strings in the encoding specified 4594** by the eTextRep argument. The collating function must return an 4595** integer that is negative, zero, or positive 4596** if the first string is less than, equal to, or greater than the second, 4597** respectively. A collating function must always return the same answer 4598** given the same inputs. If two or more collating functions are registered 4599** to the same collation name (using different eTextRep values) then all 4600** must give an equivalent answer when invoked with equivalent strings. 4601** The collating function must obey the following properties for all 4602** strings A, B, and C: 4603** 4604** <ol> 4605** <li> If A==B then B==A. 4606** <li> If A==B and B==C then A==C. 4607** <li> If A<B THEN B>A. 4608** <li> If A<B and B<C then A<C. 4609** </ol> 4610** 4611** If a collating function fails any of the above constraints and that 4612** collating function is registered and used, then the behavior of SQLite 4613** is undefined. 4614** 4615** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4616** with the addition that the xDestroy callback is invoked on pArg when 4617** the collating function is deleted. 4618** ^Collating functions are deleted when they are overridden by later 4619** calls to the collation creation functions or when the 4620** [database connection] is closed using [sqlite3_close()]. 4621** 4622** ^The xDestroy callback is <u>not</u> called if the 4623** sqlite3_create_collation_v2() function fails. Applications that invoke 4624** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4625** check the return code and dispose of the application data pointer 4626** themselves rather than expecting SQLite to deal with it for them. 4627** This is different from every other SQLite interface. The inconsistency 4628** is unfortunate but cannot be changed without breaking backwards 4629** compatibility. 4630** 4631** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4632*/ 4633int sqlite3_create_collation( 4634 sqlite3*, 4635 const char *zName, 4636 int eTextRep, 4637 void *pArg, 4638 int(*xCompare)(void*,int,const void*,int,const void*) 4639); 4640int sqlite3_create_collation_v2( 4641 sqlite3*, 4642 const char *zName, 4643 int eTextRep, 4644 void *pArg, 4645 int(*xCompare)(void*,int,const void*,int,const void*), 4646 void(*xDestroy)(void*) 4647); 4648int sqlite3_create_collation16( 4649 sqlite3*, 4650 const void *zName, 4651 int eTextRep, 4652 void *pArg, 4653 int(*xCompare)(void*,int,const void*,int,const void*) 4654); 4655 4656/* 4657** CAPI3REF: Collation Needed Callbacks 4658** 4659** ^To avoid having to register all collation sequences before a database 4660** can be used, a single callback function may be registered with the 4661** [database connection] to be invoked whenever an undefined collation 4662** sequence is required. 4663** 4664** ^If the function is registered using the sqlite3_collation_needed() API, 4665** then it is passed the names of undefined collation sequences as strings 4666** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4667** the names are passed as UTF-16 in machine native byte order. 4668** ^A call to either function replaces the existing collation-needed callback. 4669** 4670** ^(When the callback is invoked, the first argument passed is a copy 4671** of the second argument to sqlite3_collation_needed() or 4672** sqlite3_collation_needed16(). The second argument is the database 4673** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4674** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4675** sequence function required. The fourth parameter is the name of the 4676** required collation sequence.)^ 4677** 4678** The callback function should register the desired collation using 4679** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4680** [sqlite3_create_collation_v2()]. 4681*/ 4682int sqlite3_collation_needed( 4683 sqlite3*, 4684 void*, 4685 void(*)(void*,sqlite3*,int eTextRep,const char*) 4686); 4687int sqlite3_collation_needed16( 4688 sqlite3*, 4689 void*, 4690 void(*)(void*,sqlite3*,int eTextRep,const void*) 4691); 4692 4693#ifdef SQLITE_HAS_CODEC 4694/* 4695** Specify the key for an encrypted database. This routine should be 4696** called right after sqlite3_open(). 4697** 4698** The code to implement this API is not available in the public release 4699** of SQLite. 4700*/ 4701int sqlite3_key( 4702 sqlite3 *db, /* Database to be rekeyed */ 4703 const void *pKey, int nKey /* The key */ 4704); 4705int sqlite3_key_v2( 4706 sqlite3 *db, /* Database to be rekeyed */ 4707 const char *zDbName, /* Name of the database */ 4708 const void *pKey, int nKey /* The key */ 4709); 4710 4711/* 4712** Change the key on an open database. If the current database is not 4713** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4714** database is decrypted. 4715** 4716** The code to implement this API is not available in the public release 4717** of SQLite. 4718*/ 4719int sqlite3_rekey( 4720 sqlite3 *db, /* Database to be rekeyed */ 4721 const void *pKey, int nKey /* The new key */ 4722); 4723int sqlite3_rekey_v2( 4724 sqlite3 *db, /* Database to be rekeyed */ 4725 const char *zDbName, /* Name of the database */ 4726 const void *pKey, int nKey /* The new key */ 4727); 4728 4729/* 4730** Specify the activation key for a SEE database. Unless 4731** activated, none of the SEE routines will work. 4732*/ 4733void sqlite3_activate_see( 4734 const char *zPassPhrase /* Activation phrase */ 4735); 4736#endif 4737 4738#ifdef SQLITE_ENABLE_CEROD 4739/* 4740** Specify the activation key for a CEROD database. Unless 4741** activated, none of the CEROD routines will work. 4742*/ 4743void sqlite3_activate_cerod( 4744 const char *zPassPhrase /* Activation phrase */ 4745); 4746#endif 4747 4748/* 4749** CAPI3REF: Suspend Execution For A Short Time 4750** 4751** The sqlite3_sleep() function causes the current thread to suspend execution 4752** for at least a number of milliseconds specified in its parameter. 4753** 4754** If the operating system does not support sleep requests with 4755** millisecond time resolution, then the time will be rounded up to 4756** the nearest second. The number of milliseconds of sleep actually 4757** requested from the operating system is returned. 4758** 4759** ^SQLite implements this interface by calling the xSleep() 4760** method of the default [sqlite3_vfs] object. If the xSleep() method 4761** of the default VFS is not implemented correctly, or not implemented at 4762** all, then the behavior of sqlite3_sleep() may deviate from the description 4763** in the previous paragraphs. 4764*/ 4765int sqlite3_sleep(int); 4766 4767/* 4768** CAPI3REF: Name Of The Folder Holding Temporary Files 4769** 4770** ^(If this global variable is made to point to a string which is 4771** the name of a folder (a.k.a. directory), then all temporary files 4772** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4773** will be placed in that directory.)^ ^If this variable 4774** is a NULL pointer, then SQLite performs a search for an appropriate 4775** temporary file directory. 4776** 4777** Applications are strongly discouraged from using this global variable. 4778** It is required to set a temporary folder on Windows Runtime (WinRT). 4779** But for all other platforms, it is highly recommended that applications 4780** neither read nor write this variable. This global variable is a relic 4781** that exists for backwards compatibility of legacy applications and should 4782** be avoided in new projects. 4783** 4784** It is not safe to read or modify this variable in more than one 4785** thread at a time. It is not safe to read or modify this variable 4786** if a [database connection] is being used at the same time in a separate 4787** thread. 4788** It is intended that this variable be set once 4789** as part of process initialization and before any SQLite interface 4790** routines have been called and that this variable remain unchanged 4791** thereafter. 4792** 4793** ^The [temp_store_directory pragma] may modify this variable and cause 4794** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4795** the [temp_store_directory pragma] always assumes that any string 4796** that this variable points to is held in memory obtained from 4797** [sqlite3_malloc] and the pragma may attempt to free that memory 4798** using [sqlite3_free]. 4799** Hence, if this variable is modified directly, either it should be 4800** made NULL or made to point to memory obtained from [sqlite3_malloc] 4801** or else the use of the [temp_store_directory pragma] should be avoided. 4802** Except when requested by the [temp_store_directory pragma], SQLite 4803** does not free the memory that sqlite3_temp_directory points to. If 4804** the application wants that memory to be freed, it must do 4805** so itself, taking care to only do so after all [database connection] 4806** objects have been destroyed. 4807** 4808** <b>Note to Windows Runtime users:</b> The temporary directory must be set 4809** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 4810** features that require the use of temporary files may fail. Here is an 4811** example of how to do this using C++ with the Windows Runtime: 4812** 4813** <blockquote><pre> 4814** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 4815** TemporaryFolder->Path->Data(); 4816** char zPathBuf[MAX_PATH + 1]; 4817** memset(zPathBuf, 0, sizeof(zPathBuf)); 4818** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 4819** NULL, NULL); 4820** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 4821** </pre></blockquote> 4822*/ 4823SQLITE_EXTERN char *sqlite3_temp_directory; 4824 4825/* 4826** CAPI3REF: Name Of The Folder Holding Database Files 4827** 4828** ^(If this global variable is made to point to a string which is 4829** the name of a folder (a.k.a. directory), then all database files 4830** specified with a relative pathname and created or accessed by 4831** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 4832** to be relative to that directory.)^ ^If this variable is a NULL 4833** pointer, then SQLite assumes that all database files specified 4834** with a relative pathname are relative to the current directory 4835** for the process. Only the windows VFS makes use of this global 4836** variable; it is ignored by the unix VFS. 4837** 4838** Changing the value of this variable while a database connection is 4839** open can result in a corrupt database. 4840** 4841** It is not safe to read or modify this variable in more than one 4842** thread at a time. It is not safe to read or modify this variable 4843** if a [database connection] is being used at the same time in a separate 4844** thread. 4845** It is intended that this variable be set once 4846** as part of process initialization and before any SQLite interface 4847** routines have been called and that this variable remain unchanged 4848** thereafter. 4849** 4850** ^The [data_store_directory pragma] may modify this variable and cause 4851** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4852** the [data_store_directory pragma] always assumes that any string 4853** that this variable points to is held in memory obtained from 4854** [sqlite3_malloc] and the pragma may attempt to free that memory 4855** using [sqlite3_free]. 4856** Hence, if this variable is modified directly, either it should be 4857** made NULL or made to point to memory obtained from [sqlite3_malloc] 4858** or else the use of the [data_store_directory pragma] should be avoided. 4859*/ 4860SQLITE_EXTERN char *sqlite3_data_directory; 4861 4862/* 4863** CAPI3REF: Test For Auto-Commit Mode 4864** KEYWORDS: {autocommit mode} 4865** 4866** ^The sqlite3_get_autocommit() interface returns non-zero or 4867** zero if the given database connection is or is not in autocommit mode, 4868** respectively. ^Autocommit mode is on by default. 4869** ^Autocommit mode is disabled by a [BEGIN] statement. 4870** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 4871** 4872** If certain kinds of errors occur on a statement within a multi-statement 4873** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 4874** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 4875** transaction might be rolled back automatically. The only way to 4876** find out whether SQLite automatically rolled back the transaction after 4877** an error is to use this function. 4878** 4879** If another thread changes the autocommit status of the database 4880** connection while this routine is running, then the return value 4881** is undefined. 4882*/ 4883int sqlite3_get_autocommit(sqlite3*); 4884 4885/* 4886** CAPI3REF: Find The Database Handle Of A Prepared Statement 4887** 4888** ^The sqlite3_db_handle interface returns the [database connection] handle 4889** to which a [prepared statement] belongs. ^The [database connection] 4890** returned by sqlite3_db_handle is the same [database connection] 4891** that was the first argument 4892** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 4893** create the statement in the first place. 4894*/ 4895sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 4896 4897/* 4898** CAPI3REF: Return The Filename For A Database Connection 4899** 4900** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 4901** associated with database N of connection D. ^The main database file 4902** has the name "main". If there is no attached database N on the database 4903** connection D, or if database N is a temporary or in-memory database, then 4904** a NULL pointer is returned. 4905** 4906** ^The filename returned by this function is the output of the 4907** xFullPathname method of the [VFS]. ^In other words, the filename 4908** will be an absolute pathname, even if the filename used 4909** to open the database originally was a URI or relative pathname. 4910*/ 4911const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 4912 4913/* 4914** CAPI3REF: Determine if a database is read-only 4915** 4916** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 4917** of connection D is read-only, 0 if it is read/write, or -1 if N is not 4918** the name of a database on connection D. 4919*/ 4920int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 4921 4922/* 4923** CAPI3REF: Find the next prepared statement 4924** 4925** ^This interface returns a pointer to the next [prepared statement] after 4926** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 4927** then this interface returns a pointer to the first prepared statement 4928** associated with the database connection pDb. ^If no prepared statement 4929** satisfies the conditions of this routine, it returns NULL. 4930** 4931** The [database connection] pointer D in a call to 4932** [sqlite3_next_stmt(D,S)] must refer to an open database 4933** connection and in particular must not be a NULL pointer. 4934*/ 4935sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 4936 4937/* 4938** CAPI3REF: Commit And Rollback Notification Callbacks 4939** 4940** ^The sqlite3_commit_hook() interface registers a callback 4941** function to be invoked whenever a transaction is [COMMIT | committed]. 4942** ^Any callback set by a previous call to sqlite3_commit_hook() 4943** for the same database connection is overridden. 4944** ^The sqlite3_rollback_hook() interface registers a callback 4945** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 4946** ^Any callback set by a previous call to sqlite3_rollback_hook() 4947** for the same database connection is overridden. 4948** ^The pArg argument is passed through to the callback. 4949** ^If the callback on a commit hook function returns non-zero, 4950** then the commit is converted into a rollback. 4951** 4952** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 4953** return the P argument from the previous call of the same function 4954** on the same [database connection] D, or NULL for 4955** the first call for each function on D. 4956** 4957** The commit and rollback hook callbacks are not reentrant. 4958** The callback implementation must not do anything that will modify 4959** the database connection that invoked the callback. Any actions 4960** to modify the database connection must be deferred until after the 4961** completion of the [sqlite3_step()] call that triggered the commit 4962** or rollback hook in the first place. 4963** Note that running any other SQL statements, including SELECT statements, 4964** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 4965** the database connections for the meaning of "modify" in this paragraph. 4966** 4967** ^Registering a NULL function disables the callback. 4968** 4969** ^When the commit hook callback routine returns zero, the [COMMIT] 4970** operation is allowed to continue normally. ^If the commit hook 4971** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 4972** ^The rollback hook is invoked on a rollback that results from a commit 4973** hook returning non-zero, just as it would be with any other rollback. 4974** 4975** ^For the purposes of this API, a transaction is said to have been 4976** rolled back if an explicit "ROLLBACK" statement is executed, or 4977** an error or constraint causes an implicit rollback to occur. 4978** ^The rollback callback is not invoked if a transaction is 4979** automatically rolled back because the database connection is closed. 4980** 4981** See also the [sqlite3_update_hook()] interface. 4982*/ 4983void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 4984void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 4985 4986/* 4987** CAPI3REF: Data Change Notification Callbacks 4988** 4989** ^The sqlite3_update_hook() interface registers a callback function 4990** with the [database connection] identified by the first argument 4991** to be invoked whenever a row is updated, inserted or deleted in 4992** a rowid table. 4993** ^Any callback set by a previous call to this function 4994** for the same database connection is overridden. 4995** 4996** ^The second argument is a pointer to the function to invoke when a 4997** row is updated, inserted or deleted in a rowid table. 4998** ^The first argument to the callback is a copy of the third argument 4999** to sqlite3_update_hook(). 5000** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5001** or [SQLITE_UPDATE], depending on the operation that caused the callback 5002** to be invoked. 5003** ^The third and fourth arguments to the callback contain pointers to the 5004** database and table name containing the affected row. 5005** ^The final callback parameter is the [rowid] of the row. 5006** ^In the case of an update, this is the [rowid] after the update takes place. 5007** 5008** ^(The update hook is not invoked when internal system tables are 5009** modified (i.e. sqlite_master and sqlite_sequence).)^ 5010** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5011** 5012** ^In the current implementation, the update hook 5013** is not invoked when duplication rows are deleted because of an 5014** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5015** invoked when rows are deleted using the [truncate optimization]. 5016** The exceptions defined in this paragraph might change in a future 5017** release of SQLite. 5018** 5019** The update hook implementation must not do anything that will modify 5020** the database connection that invoked the update hook. Any actions 5021** to modify the database connection must be deferred until after the 5022** completion of the [sqlite3_step()] call that triggered the update hook. 5023** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5024** database connections for the meaning of "modify" in this paragraph. 5025** 5026** ^The sqlite3_update_hook(D,C,P) function 5027** returns the P argument from the previous call 5028** on the same [database connection] D, or NULL for 5029** the first call on D. 5030** 5031** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 5032** interfaces. 5033*/ 5034void *sqlite3_update_hook( 5035 sqlite3*, 5036 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5037 void* 5038); 5039 5040/* 5041** CAPI3REF: Enable Or Disable Shared Pager Cache 5042** 5043** ^(This routine enables or disables the sharing of the database cache 5044** and schema data structures between [database connection | connections] 5045** to the same database. Sharing is enabled if the argument is true 5046** and disabled if the argument is false.)^ 5047** 5048** ^Cache sharing is enabled and disabled for an entire process. 5049** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 5050** sharing was enabled or disabled for each thread separately. 5051** 5052** ^(The cache sharing mode set by this interface effects all subsequent 5053** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5054** Existing database connections continue use the sharing mode 5055** that was in effect at the time they were opened.)^ 5056** 5057** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5058** successfully. An [error code] is returned otherwise.)^ 5059** 5060** ^Shared cache is disabled by default. But this might change in 5061** future releases of SQLite. Applications that care about shared 5062** cache setting should set it explicitly. 5063** 5064** This interface is threadsafe on processors where writing a 5065** 32-bit integer is atomic. 5066** 5067** See Also: [SQLite Shared-Cache Mode] 5068*/ 5069int sqlite3_enable_shared_cache(int); 5070 5071/* 5072** CAPI3REF: Attempt To Free Heap Memory 5073** 5074** ^The sqlite3_release_memory() interface attempts to free N bytes 5075** of heap memory by deallocating non-essential memory allocations 5076** held by the database library. Memory used to cache database 5077** pages to improve performance is an example of non-essential memory. 5078** ^sqlite3_release_memory() returns the number of bytes actually freed, 5079** which might be more or less than the amount requested. 5080** ^The sqlite3_release_memory() routine is a no-op returning zero 5081** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5082** 5083** See also: [sqlite3_db_release_memory()] 5084*/ 5085int sqlite3_release_memory(int); 5086 5087/* 5088** CAPI3REF: Free Memory Used By A Database Connection 5089** 5090** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5091** memory as possible from database connection D. Unlike the 5092** [sqlite3_release_memory()] interface, this interface is in effect even 5093** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5094** omitted. 5095** 5096** See also: [sqlite3_release_memory()] 5097*/ 5098int sqlite3_db_release_memory(sqlite3*); 5099 5100/* 5101** CAPI3REF: Impose A Limit On Heap Size 5102** 5103** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5104** soft limit on the amount of heap memory that may be allocated by SQLite. 5105** ^SQLite strives to keep heap memory utilization below the soft heap 5106** limit by reducing the number of pages held in the page cache 5107** as heap memory usages approaches the limit. 5108** ^The soft heap limit is "soft" because even though SQLite strives to stay 5109** below the limit, it will exceed the limit rather than generate 5110** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5111** is advisory only. 5112** 5113** ^The return value from sqlite3_soft_heap_limit64() is the size of 5114** the soft heap limit prior to the call, or negative in the case of an 5115** error. ^If the argument N is negative 5116** then no change is made to the soft heap limit. Hence, the current 5117** size of the soft heap limit can be determined by invoking 5118** sqlite3_soft_heap_limit64() with a negative argument. 5119** 5120** ^If the argument N is zero then the soft heap limit is disabled. 5121** 5122** ^(The soft heap limit is not enforced in the current implementation 5123** if one or more of following conditions are true: 5124** 5125** <ul> 5126** <li> The soft heap limit is set to zero. 5127** <li> Memory accounting is disabled using a combination of the 5128** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5129** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5130** <li> An alternative page cache implementation is specified using 5131** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5132** <li> The page cache allocates from its own memory pool supplied 5133** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5134** from the heap. 5135** </ul>)^ 5136** 5137** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 5138** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5139** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5140** the soft heap limit is enforced on every memory allocation. Without 5141** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5142** when memory is allocated by the page cache. Testing suggests that because 5143** the page cache is the predominate memory user in SQLite, most 5144** applications will achieve adequate soft heap limit enforcement without 5145** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5146** 5147** The circumstances under which SQLite will enforce the soft heap limit may 5148** changes in future releases of SQLite. 5149*/ 5150sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5151 5152/* 5153** CAPI3REF: Deprecated Soft Heap Limit Interface 5154** DEPRECATED 5155** 5156** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5157** interface. This routine is provided for historical compatibility 5158** only. All new applications should use the 5159** [sqlite3_soft_heap_limit64()] interface rather than this one. 5160*/ 5161SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5162 5163 5164/* 5165** CAPI3REF: Extract Metadata About A Column Of A Table 5166** 5167** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5168** information about column C of table T in database D 5169** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5170** interface returns SQLITE_OK and fills in the non-NULL pointers in 5171** the final five arguments with appropriate values if the specified 5172** column exists. ^The sqlite3_table_column_metadata() interface returns 5173** SQLITE_ERROR and if the specified column does not exist. 5174** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5175** NULL pointer, then this routine simply checks for the existance of the 5176** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5177** does not. 5178** 5179** ^The column is identified by the second, third and fourth parameters to 5180** this function. ^(The second parameter is either the name of the database 5181** (i.e. "main", "temp", or an attached database) containing the specified 5182** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5183** for the table using the same algorithm used by the database engine to 5184** resolve unqualified table references. 5185** 5186** ^The third and fourth parameters to this function are the table and column 5187** name of the desired column, respectively. 5188** 5189** ^Metadata is returned by writing to the memory locations passed as the 5th 5190** and subsequent parameters to this function. ^Any of these arguments may be 5191** NULL, in which case the corresponding element of metadata is omitted. 5192** 5193** ^(<blockquote> 5194** <table border="1"> 5195** <tr><th> Parameter <th> Output<br>Type <th> Description 5196** 5197** <tr><td> 5th <td> const char* <td> Data type 5198** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5199** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5200** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5201** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5202** </table> 5203** </blockquote>)^ 5204** 5205** ^The memory pointed to by the character pointers returned for the 5206** declaration type and collation sequence is valid until the next 5207** call to any SQLite API function. 5208** 5209** ^If the specified table is actually a view, an [error code] is returned. 5210** 5211** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5212** is not a [WITHOUT ROWID] table and an 5213** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5214** parameters are set for the explicitly declared column. ^(If there is no 5215** [INTEGER PRIMARY KEY] column, then the outputs 5216** for the [rowid] are set as follows: 5217** 5218** <pre> 5219** data type: "INTEGER" 5220** collation sequence: "BINARY" 5221** not null: 0 5222** primary key: 1 5223** auto increment: 0 5224** </pre>)^ 5225** 5226** ^This function causes all database schemas to be read from disk and 5227** parsed, if that has not already been done, and returns an error if 5228** any errors are encountered while loading the schema. 5229*/ 5230int sqlite3_table_column_metadata( 5231 sqlite3 *db, /* Connection handle */ 5232 const char *zDbName, /* Database name or NULL */ 5233 const char *zTableName, /* Table name */ 5234 const char *zColumnName, /* Column name */ 5235 char const **pzDataType, /* OUTPUT: Declared data type */ 5236 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5237 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5238 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5239 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5240); 5241 5242/* 5243** CAPI3REF: Load An Extension 5244** 5245** ^This interface loads an SQLite extension library from the named file. 5246** 5247** ^The sqlite3_load_extension() interface attempts to load an 5248** [SQLite extension] library contained in the file zFile. If 5249** the file cannot be loaded directly, attempts are made to load 5250** with various operating-system specific extensions added. 5251** So for example, if "samplelib" cannot be loaded, then names like 5252** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5253** be tried also. 5254** 5255** ^The entry point is zProc. 5256** ^(zProc may be 0, in which case SQLite will try to come up with an 5257** entry point name on its own. It first tries "sqlite3_extension_init". 5258** If that does not work, it constructs a name "sqlite3_X_init" where the 5259** X is consists of the lower-case equivalent of all ASCII alphabetic 5260** characters in the filename from the last "/" to the first following 5261** "." and omitting any initial "lib".)^ 5262** ^The sqlite3_load_extension() interface returns 5263** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5264** ^If an error occurs and pzErrMsg is not 0, then the 5265** [sqlite3_load_extension()] interface shall attempt to 5266** fill *pzErrMsg with error message text stored in memory 5267** obtained from [sqlite3_malloc()]. The calling function 5268** should free this memory by calling [sqlite3_free()]. 5269** 5270** ^Extension loading must be enabled using 5271** [sqlite3_enable_load_extension()] prior to calling this API, 5272** otherwise an error will be returned. 5273** 5274** See also the [load_extension() SQL function]. 5275*/ 5276int sqlite3_load_extension( 5277 sqlite3 *db, /* Load the extension into this database connection */ 5278 const char *zFile, /* Name of the shared library containing extension */ 5279 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5280 char **pzErrMsg /* Put error message here if not 0 */ 5281); 5282 5283/* 5284** CAPI3REF: Enable Or Disable Extension Loading 5285** 5286** ^So as not to open security holes in older applications that are 5287** unprepared to deal with [extension loading], and as a means of disabling 5288** [extension loading] while evaluating user-entered SQL, the following API 5289** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5290** 5291** ^Extension loading is off by default. 5292** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5293** to turn extension loading on and call it with onoff==0 to turn 5294** it back off again. 5295*/ 5296int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5297 5298/* 5299** CAPI3REF: Automatically Load Statically Linked Extensions 5300** 5301** ^This interface causes the xEntryPoint() function to be invoked for 5302** each new [database connection] that is created. The idea here is that 5303** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5304** that is to be automatically loaded into all new database connections. 5305** 5306** ^(Even though the function prototype shows that xEntryPoint() takes 5307** no arguments and returns void, SQLite invokes xEntryPoint() with three 5308** arguments and expects and integer result as if the signature of the 5309** entry point where as follows: 5310** 5311** <blockquote><pre> 5312** int xEntryPoint( 5313** sqlite3 *db, 5314** const char **pzErrMsg, 5315** const struct sqlite3_api_routines *pThunk 5316** ); 5317** </pre></blockquote>)^ 5318** 5319** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5320** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5321** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5322** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5323** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5324** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5325** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 5326** 5327** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 5328** on the list of automatic extensions is a harmless no-op. ^No entry point 5329** will be called more than once for each database connection that is opened. 5330** 5331** See also: [sqlite3_reset_auto_extension()] 5332** and [sqlite3_cancel_auto_extension()] 5333*/ 5334int sqlite3_auto_extension(void (*xEntryPoint)(void)); 5335 5336/* 5337** CAPI3REF: Cancel Automatic Extension Loading 5338** 5339** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 5340** initialization routine X that was registered using a prior call to 5341** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 5342** routine returns 1 if initialization routine X was successfully 5343** unregistered and it returns 0 if X was not on the list of initialization 5344** routines. 5345*/ 5346int sqlite3_cancel_auto_extension(void (*xEntryPoint)(void)); 5347 5348/* 5349** CAPI3REF: Reset Automatic Extension Loading 5350** 5351** ^This interface disables all automatic extensions previously 5352** registered using [sqlite3_auto_extension()]. 5353*/ 5354void sqlite3_reset_auto_extension(void); 5355 5356/* 5357** The interface to the virtual-table mechanism is currently considered 5358** to be experimental. The interface might change in incompatible ways. 5359** If this is a problem for you, do not use the interface at this time. 5360** 5361** When the virtual-table mechanism stabilizes, we will declare the 5362** interface fixed, support it indefinitely, and remove this comment. 5363*/ 5364 5365/* 5366** Structures used by the virtual table interface 5367*/ 5368typedef struct sqlite3_vtab sqlite3_vtab; 5369typedef struct sqlite3_index_info sqlite3_index_info; 5370typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 5371typedef struct sqlite3_module sqlite3_module; 5372 5373/* 5374** CAPI3REF: Virtual Table Object 5375** KEYWORDS: sqlite3_module {virtual table module} 5376** 5377** This structure, sometimes called a "virtual table module", 5378** defines the implementation of a [virtual tables]. 5379** This structure consists mostly of methods for the module. 5380** 5381** ^A virtual table module is created by filling in a persistent 5382** instance of this structure and passing a pointer to that instance 5383** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 5384** ^The registration remains valid until it is replaced by a different 5385** module or until the [database connection] closes. The content 5386** of this structure must not change while it is registered with 5387** any database connection. 5388*/ 5389struct sqlite3_module { 5390 int iVersion; 5391 int (*xCreate)(sqlite3*, void *pAux, 5392 int argc, const char *const*argv, 5393 sqlite3_vtab **ppVTab, char**); 5394 int (*xConnect)(sqlite3*, void *pAux, 5395 int argc, const char *const*argv, 5396 sqlite3_vtab **ppVTab, char**); 5397 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 5398 int (*xDisconnect)(sqlite3_vtab *pVTab); 5399 int (*xDestroy)(sqlite3_vtab *pVTab); 5400 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 5401 int (*xClose)(sqlite3_vtab_cursor*); 5402 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 5403 int argc, sqlite3_value **argv); 5404 int (*xNext)(sqlite3_vtab_cursor*); 5405 int (*xEof)(sqlite3_vtab_cursor*); 5406 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 5407 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 5408 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 5409 int (*xBegin)(sqlite3_vtab *pVTab); 5410 int (*xSync)(sqlite3_vtab *pVTab); 5411 int (*xCommit)(sqlite3_vtab *pVTab); 5412 int (*xRollback)(sqlite3_vtab *pVTab); 5413 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 5414 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 5415 void **ppArg); 5416 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 5417 /* The methods above are in version 1 of the sqlite_module object. Those 5418 ** below are for version 2 and greater. */ 5419 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 5420 int (*xRelease)(sqlite3_vtab *pVTab, int); 5421 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 5422}; 5423 5424/* 5425** CAPI3REF: Virtual Table Indexing Information 5426** KEYWORDS: sqlite3_index_info 5427** 5428** The sqlite3_index_info structure and its substructures is used as part 5429** of the [virtual table] interface to 5430** pass information into and receive the reply from the [xBestIndex] 5431** method of a [virtual table module]. The fields under **Inputs** are the 5432** inputs to xBestIndex and are read-only. xBestIndex inserts its 5433** results into the **Outputs** fields. 5434** 5435** ^(The aConstraint[] array records WHERE clause constraints of the form: 5436** 5437** <blockquote>column OP expr</blockquote> 5438** 5439** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 5440** stored in aConstraint[].op using one of the 5441** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 5442** ^(The index of the column is stored in 5443** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5444** expr on the right-hand side can be evaluated (and thus the constraint 5445** is usable) and false if it cannot.)^ 5446** 5447** ^The optimizer automatically inverts terms of the form "expr OP column" 5448** and makes other simplifications to the WHERE clause in an attempt to 5449** get as many WHERE clause terms into the form shown above as possible. 5450** ^The aConstraint[] array only reports WHERE clause terms that are 5451** relevant to the particular virtual table being queried. 5452** 5453** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5454** ^Each term of aOrderBy records a column of the ORDER BY clause. 5455** 5456** The [xBestIndex] method must fill aConstraintUsage[] with information 5457** about what parameters to pass to xFilter. ^If argvIndex>0 then 5458** the right-hand side of the corresponding aConstraint[] is evaluated 5459** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5460** is true, then the constraint is assumed to be fully handled by the 5461** virtual table and is not checked again by SQLite.)^ 5462** 5463** ^The idxNum and idxPtr values are recorded and passed into the 5464** [xFilter] method. 5465** ^[sqlite3_free()] is used to free idxPtr if and only if 5466** needToFreeIdxPtr is true. 5467** 5468** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5469** the correct order to satisfy the ORDER BY clause so that no separate 5470** sorting step is required. 5471** 5472** ^The estimatedCost value is an estimate of the cost of a particular 5473** strategy. A cost of N indicates that the cost of the strategy is similar 5474** to a linear scan of an SQLite table with N rows. A cost of log(N) 5475** indicates that the expense of the operation is similar to that of a 5476** binary search on a unique indexed field of an SQLite table with N rows. 5477** 5478** ^The estimatedRows value is an estimate of the number of rows that 5479** will be returned by the strategy. 5480** 5481** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 5482** structure for SQLite version 3.8.2. If a virtual table extension is 5483** used with an SQLite version earlier than 3.8.2, the results of attempting 5484** to read or write the estimatedRows field are undefined (but are likely 5485** to included crashing the application). The estimatedRows field should 5486** therefore only be used if [sqlite3_libversion_number()] returns a 5487** value greater than or equal to 3008002. 5488*/ 5489struct sqlite3_index_info { 5490 /* Inputs */ 5491 int nConstraint; /* Number of entries in aConstraint */ 5492 struct sqlite3_index_constraint { 5493 int iColumn; /* Column on left-hand side of constraint */ 5494 unsigned char op; /* Constraint operator */ 5495 unsigned char usable; /* True if this constraint is usable */ 5496 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5497 } *aConstraint; /* Table of WHERE clause constraints */ 5498 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5499 struct sqlite3_index_orderby { 5500 int iColumn; /* Column number */ 5501 unsigned char desc; /* True for DESC. False for ASC. */ 5502 } *aOrderBy; /* The ORDER BY clause */ 5503 /* Outputs */ 5504 struct sqlite3_index_constraint_usage { 5505 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5506 unsigned char omit; /* Do not code a test for this constraint */ 5507 } *aConstraintUsage; 5508 int idxNum; /* Number used to identify the index */ 5509 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5510 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5511 int orderByConsumed; /* True if output is already ordered */ 5512 double estimatedCost; /* Estimated cost of using this index */ 5513 /* Fields below are only available in SQLite 3.8.2 and later */ 5514 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 5515}; 5516 5517/* 5518** CAPI3REF: Virtual Table Constraint Operator Codes 5519** 5520** These macros defined the allowed values for the 5521** [sqlite3_index_info].aConstraint[].op field. Each value represents 5522** an operator that is part of a constraint term in the wHERE clause of 5523** a query that uses a [virtual table]. 5524*/ 5525#define SQLITE_INDEX_CONSTRAINT_EQ 2 5526#define SQLITE_INDEX_CONSTRAINT_GT 4 5527#define SQLITE_INDEX_CONSTRAINT_LE 8 5528#define SQLITE_INDEX_CONSTRAINT_LT 16 5529#define SQLITE_INDEX_CONSTRAINT_GE 32 5530#define SQLITE_INDEX_CONSTRAINT_MATCH 64 5531 5532/* 5533** CAPI3REF: Register A Virtual Table Implementation 5534** 5535** ^These routines are used to register a new [virtual table module] name. 5536** ^Module names must be registered before 5537** creating a new [virtual table] using the module and before using a 5538** preexisting [virtual table] for the module. 5539** 5540** ^The module name is registered on the [database connection] specified 5541** by the first parameter. ^The name of the module is given by the 5542** second parameter. ^The third parameter is a pointer to 5543** the implementation of the [virtual table module]. ^The fourth 5544** parameter is an arbitrary client data pointer that is passed through 5545** into the [xCreate] and [xConnect] methods of the virtual table module 5546** when a new virtual table is be being created or reinitialized. 5547** 5548** ^The sqlite3_create_module_v2() interface has a fifth parameter which 5549** is a pointer to a destructor for the pClientData. ^SQLite will 5550** invoke the destructor function (if it is not NULL) when SQLite 5551** no longer needs the pClientData pointer. ^The destructor will also 5552** be invoked if the call to sqlite3_create_module_v2() fails. 5553** ^The sqlite3_create_module() 5554** interface is equivalent to sqlite3_create_module_v2() with a NULL 5555** destructor. 5556*/ 5557int sqlite3_create_module( 5558 sqlite3 *db, /* SQLite connection to register module with */ 5559 const char *zName, /* Name of the module */ 5560 const sqlite3_module *p, /* Methods for the module */ 5561 void *pClientData /* Client data for xCreate/xConnect */ 5562); 5563int sqlite3_create_module_v2( 5564 sqlite3 *db, /* SQLite connection to register module with */ 5565 const char *zName, /* Name of the module */ 5566 const sqlite3_module *p, /* Methods for the module */ 5567 void *pClientData, /* Client data for xCreate/xConnect */ 5568 void(*xDestroy)(void*) /* Module destructor function */ 5569); 5570 5571/* 5572** CAPI3REF: Virtual Table Instance Object 5573** KEYWORDS: sqlite3_vtab 5574** 5575** Every [virtual table module] implementation uses a subclass 5576** of this object to describe a particular instance 5577** of the [virtual table]. Each subclass will 5578** be tailored to the specific needs of the module implementation. 5579** The purpose of this superclass is to define certain fields that are 5580** common to all module implementations. 5581** 5582** ^Virtual tables methods can set an error message by assigning a 5583** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 5584** take care that any prior string is freed by a call to [sqlite3_free()] 5585** prior to assigning a new string to zErrMsg. ^After the error message 5586** is delivered up to the client application, the string will be automatically 5587** freed by sqlite3_free() and the zErrMsg field will be zeroed. 5588*/ 5589struct sqlite3_vtab { 5590 const sqlite3_module *pModule; /* The module for this virtual table */ 5591 int nRef; /* NO LONGER USED */ 5592 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 5593 /* Virtual table implementations will typically add additional fields */ 5594}; 5595 5596/* 5597** CAPI3REF: Virtual Table Cursor Object 5598** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 5599** 5600** Every [virtual table module] implementation uses a subclass of the 5601** following structure to describe cursors that point into the 5602** [virtual table] and are used 5603** to loop through the virtual table. Cursors are created using the 5604** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 5605** by the [sqlite3_module.xClose | xClose] method. Cursors are used 5606** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 5607** of the module. Each module implementation will define 5608** the content of a cursor structure to suit its own needs. 5609** 5610** This superclass exists in order to define fields of the cursor that 5611** are common to all implementations. 5612*/ 5613struct sqlite3_vtab_cursor { 5614 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 5615 /* Virtual table implementations will typically add additional fields */ 5616}; 5617 5618/* 5619** CAPI3REF: Declare The Schema Of A Virtual Table 5620** 5621** ^The [xCreate] and [xConnect] methods of a 5622** [virtual table module] call this interface 5623** to declare the format (the names and datatypes of the columns) of 5624** the virtual tables they implement. 5625*/ 5626int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 5627 5628/* 5629** CAPI3REF: Overload A Function For A Virtual Table 5630** 5631** ^(Virtual tables can provide alternative implementations of functions 5632** using the [xFindFunction] method of the [virtual table module]. 5633** But global versions of those functions 5634** must exist in order to be overloaded.)^ 5635** 5636** ^(This API makes sure a global version of a function with a particular 5637** name and number of parameters exists. If no such function exists 5638** before this API is called, a new function is created.)^ ^The implementation 5639** of the new function always causes an exception to be thrown. So 5640** the new function is not good for anything by itself. Its only 5641** purpose is to be a placeholder function that can be overloaded 5642** by a [virtual table]. 5643*/ 5644int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5645 5646/* 5647** The interface to the virtual-table mechanism defined above (back up 5648** to a comment remarkably similar to this one) is currently considered 5649** to be experimental. The interface might change in incompatible ways. 5650** If this is a problem for you, do not use the interface at this time. 5651** 5652** When the virtual-table mechanism stabilizes, we will declare the 5653** interface fixed, support it indefinitely, and remove this comment. 5654*/ 5655 5656/* 5657** CAPI3REF: A Handle To An Open BLOB 5658** KEYWORDS: {BLOB handle} {BLOB handles} 5659** 5660** An instance of this object represents an open BLOB on which 5661** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5662** ^Objects of this type are created by [sqlite3_blob_open()] 5663** and destroyed by [sqlite3_blob_close()]. 5664** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5665** can be used to read or write small subsections of the BLOB. 5666** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5667*/ 5668typedef struct sqlite3_blob sqlite3_blob; 5669 5670/* 5671** CAPI3REF: Open A BLOB For Incremental I/O 5672** 5673** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5674** in row iRow, column zColumn, table zTable in database zDb; 5675** in other words, the same BLOB that would be selected by: 5676** 5677** <pre> 5678** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5679** </pre>)^ 5680** 5681** ^(Parameter zDb is not the filename that contains the database, but 5682** rather the symbolic name of the database. For attached databases, this is 5683** the name that appears after the AS keyword in the [ATTACH] statement. 5684** For the main database file, the database name is "main". For TEMP 5685** tables, the database name is "temp".)^ 5686** 5687** ^If the flags parameter is non-zero, then the BLOB is opened for read 5688** and write access. ^If the flags parameter is zero, the BLOB is opened for 5689** read-only access. 5690** 5691** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 5692** in *ppBlob. Otherwise an [error code] is returned and, unless the error 5693** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 5694** the API is not misused, it is always safe to call [sqlite3_blob_close()] 5695** on *ppBlob after this function it returns. 5696** 5697** This function fails with SQLITE_ERROR if any of the following are true: 5698** <ul> 5699** <li> ^(Database zDb does not exist)^, 5700** <li> ^(Table zTable does not exist within database zDb)^, 5701** <li> ^(Table zTable is a WITHOUT ROWID table)^, 5702** <li> ^(Column zColumn does not exist)^, 5703** <li> ^(Row iRow is not present in the table)^, 5704** <li> ^(The specified column of row iRow contains a value that is not 5705** a TEXT or BLOB value)^, 5706** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 5707** constraint and the blob is being opened for read/write access)^, 5708** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 5709** column zColumn is part of a [child key] definition and the blob is 5710** being opened for read/write access)^. 5711** </ul> 5712** 5713** ^Unless it returns SQLITE_MISUSE, this function sets the 5714** [database connection] error code and message accessible via 5715** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 5716** 5717** 5718** ^(If the row that a BLOB handle points to is modified by an 5719** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5720** then the BLOB handle is marked as "expired". 5721** This is true if any column of the row is changed, even a column 5722** other than the one the BLOB handle is open on.)^ 5723** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5724** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5725** ^(Changes written into a BLOB prior to the BLOB expiring are not 5726** rolled back by the expiration of the BLOB. Such changes will eventually 5727** commit if the transaction continues to completion.)^ 5728** 5729** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5730** the opened blob. ^The size of a blob may not be changed by this 5731** interface. Use the [UPDATE] SQL command to change the size of a 5732** blob. 5733** 5734** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5735** and the built-in [zeroblob] SQL function may be used to create a 5736** zero-filled blob to read or write using the incremental-blob interface. 5737** 5738** To avoid a resource leak, every open [BLOB handle] should eventually 5739** be released by a call to [sqlite3_blob_close()]. 5740*/ 5741int sqlite3_blob_open( 5742 sqlite3*, 5743 const char *zDb, 5744 const char *zTable, 5745 const char *zColumn, 5746 sqlite3_int64 iRow, 5747 int flags, 5748 sqlite3_blob **ppBlob 5749); 5750 5751/* 5752** CAPI3REF: Move a BLOB Handle to a New Row 5753** 5754** ^This function is used to move an existing blob handle so that it points 5755** to a different row of the same database table. ^The new row is identified 5756** by the rowid value passed as the second argument. Only the row can be 5757** changed. ^The database, table and column on which the blob handle is open 5758** remain the same. Moving an existing blob handle to a new row can be 5759** faster than closing the existing handle and opening a new one. 5760** 5761** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5762** it must exist and there must be either a blob or text value stored in 5763** the nominated column.)^ ^If the new row is not present in the table, or if 5764** it does not contain a blob or text value, or if another error occurs, an 5765** SQLite error code is returned and the blob handle is considered aborted. 5766** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5767** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5768** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5769** always returns zero. 5770** 5771** ^This function sets the database handle error code and message. 5772*/ 5773SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5774 5775/* 5776** CAPI3REF: Close A BLOB Handle 5777** 5778** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 5779** unconditionally. Even if this routine returns an error code, the 5780** handle is still closed.)^ 5781** 5782** ^If the blob handle being closed was opened for read-write access, and if 5783** the database is in auto-commit mode and there are no other open read-write 5784** blob handles or active write statements, the current transaction is 5785** committed. ^If an error occurs while committing the transaction, an error 5786** code is returned and the transaction rolled back. 5787** 5788** Calling this function with an argument that is not a NULL pointer or an 5789** open blob handle results in undefined behaviour. ^Calling this routine 5790** with a null pointer (such as would be returned by a failed call to 5791** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 5792** is passed a valid open blob handle, the values returned by the 5793** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 5794*/ 5795int sqlite3_blob_close(sqlite3_blob *); 5796 5797/* 5798** CAPI3REF: Return The Size Of An Open BLOB 5799** 5800** ^Returns the size in bytes of the BLOB accessible via the 5801** successfully opened [BLOB handle] in its only argument. ^The 5802** incremental blob I/O routines can only read or overwriting existing 5803** blob content; they cannot change the size of a blob. 5804** 5805** This routine only works on a [BLOB handle] which has been created 5806** by a prior successful call to [sqlite3_blob_open()] and which has not 5807** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5808** to this routine results in undefined and probably undesirable behavior. 5809*/ 5810int sqlite3_blob_bytes(sqlite3_blob *); 5811 5812/* 5813** CAPI3REF: Read Data From A BLOB Incrementally 5814** 5815** ^(This function is used to read data from an open [BLOB handle] into a 5816** caller-supplied buffer. N bytes of data are copied into buffer Z 5817** from the open BLOB, starting at offset iOffset.)^ 5818** 5819** ^If offset iOffset is less than N bytes from the end of the BLOB, 5820** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 5821** less than zero, [SQLITE_ERROR] is returned and no data is read. 5822** ^The size of the blob (and hence the maximum value of N+iOffset) 5823** can be determined using the [sqlite3_blob_bytes()] interface. 5824** 5825** ^An attempt to read from an expired [BLOB handle] fails with an 5826** error code of [SQLITE_ABORT]. 5827** 5828** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 5829** Otherwise, an [error code] or an [extended error code] is returned.)^ 5830** 5831** This routine only works on a [BLOB handle] which has been created 5832** by a prior successful call to [sqlite3_blob_open()] and which has not 5833** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5834** to this routine results in undefined and probably undesirable behavior. 5835** 5836** See also: [sqlite3_blob_write()]. 5837*/ 5838int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 5839 5840/* 5841** CAPI3REF: Write Data Into A BLOB Incrementally 5842** 5843** ^(This function is used to write data into an open [BLOB handle] from a 5844** caller-supplied buffer. N bytes of data are copied from the buffer Z 5845** into the open BLOB, starting at offset iOffset.)^ 5846** 5847** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 5848** Otherwise, an [error code] or an [extended error code] is returned.)^ 5849** ^Unless SQLITE_MISUSE is returned, this function sets the 5850** [database connection] error code and message accessible via 5851** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 5852** 5853** ^If the [BLOB handle] passed as the first argument was not opened for 5854** writing (the flags parameter to [sqlite3_blob_open()] was zero), 5855** this function returns [SQLITE_READONLY]. 5856** 5857** This function may only modify the contents of the BLOB; it is 5858** not possible to increase the size of a BLOB using this API. 5859** ^If offset iOffset is less than N bytes from the end of the BLOB, 5860** [SQLITE_ERROR] is returned and no data is written. The size of the 5861** BLOB (and hence the maximum value of N+iOffset) can be determined 5862** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 5863** than zero [SQLITE_ERROR] is returned and no data is written. 5864** 5865** ^An attempt to write to an expired [BLOB handle] fails with an 5866** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 5867** before the [BLOB handle] expired are not rolled back by the 5868** expiration of the handle, though of course those changes might 5869** have been overwritten by the statement that expired the BLOB handle 5870** or by other independent statements. 5871** 5872** This routine only works on a [BLOB handle] which has been created 5873** by a prior successful call to [sqlite3_blob_open()] and which has not 5874** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5875** to this routine results in undefined and probably undesirable behavior. 5876** 5877** See also: [sqlite3_blob_read()]. 5878*/ 5879int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 5880 5881/* 5882** CAPI3REF: Virtual File System Objects 5883** 5884** A virtual filesystem (VFS) is an [sqlite3_vfs] object 5885** that SQLite uses to interact 5886** with the underlying operating system. Most SQLite builds come with a 5887** single default VFS that is appropriate for the host computer. 5888** New VFSes can be registered and existing VFSes can be unregistered. 5889** The following interfaces are provided. 5890** 5891** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 5892** ^Names are case sensitive. 5893** ^Names are zero-terminated UTF-8 strings. 5894** ^If there is no match, a NULL pointer is returned. 5895** ^If zVfsName is NULL then the default VFS is returned. 5896** 5897** ^New VFSes are registered with sqlite3_vfs_register(). 5898** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 5899** ^The same VFS can be registered multiple times without injury. 5900** ^To make an existing VFS into the default VFS, register it again 5901** with the makeDflt flag set. If two different VFSes with the 5902** same name are registered, the behavior is undefined. If a 5903** VFS is registered with a name that is NULL or an empty string, 5904** then the behavior is undefined. 5905** 5906** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 5907** ^(If the default VFS is unregistered, another VFS is chosen as 5908** the default. The choice for the new VFS is arbitrary.)^ 5909*/ 5910sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 5911int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 5912int sqlite3_vfs_unregister(sqlite3_vfs*); 5913 5914/* 5915** CAPI3REF: Mutexes 5916** 5917** The SQLite core uses these routines for thread 5918** synchronization. Though they are intended for internal 5919** use by SQLite, code that links against SQLite is 5920** permitted to use any of these routines. 5921** 5922** The SQLite source code contains multiple implementations 5923** of these mutex routines. An appropriate implementation 5924** is selected automatically at compile-time. The following 5925** implementations are available in the SQLite core: 5926** 5927** <ul> 5928** <li> SQLITE_MUTEX_PTHREADS 5929** <li> SQLITE_MUTEX_W32 5930** <li> SQLITE_MUTEX_NOOP 5931** </ul> 5932** 5933** The SQLITE_MUTEX_NOOP implementation is a set of routines 5934** that does no real locking and is appropriate for use in 5935** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 5936** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 5937** and Windows. 5938** 5939** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 5940** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 5941** implementation is included with the library. In this case the 5942** application must supply a custom mutex implementation using the 5943** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 5944** before calling sqlite3_initialize() or any other public sqlite3_ 5945** function that calls sqlite3_initialize(). 5946** 5947** ^The sqlite3_mutex_alloc() routine allocates a new 5948** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 5949** routine returns NULL if it is unable to allocate the requested 5950** mutex. The argument to sqlite3_mutex_alloc() must one of these 5951** integer constants: 5952** 5953** <ul> 5954** <li> SQLITE_MUTEX_FAST 5955** <li> SQLITE_MUTEX_RECURSIVE 5956** <li> SQLITE_MUTEX_STATIC_MASTER 5957** <li> SQLITE_MUTEX_STATIC_MEM 5958** <li> SQLITE_MUTEX_STATIC_OPEN 5959** <li> SQLITE_MUTEX_STATIC_PRNG 5960** <li> SQLITE_MUTEX_STATIC_LRU 5961** <li> SQLITE_MUTEX_STATIC_PMEM 5962** <li> SQLITE_MUTEX_STATIC_APP1 5963** <li> SQLITE_MUTEX_STATIC_APP2 5964** <li> SQLITE_MUTEX_STATIC_APP3 5965** </ul> 5966** 5967** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 5968** cause sqlite3_mutex_alloc() to create 5969** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 5970** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 5971** The mutex implementation does not need to make a distinction 5972** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 5973** not want to. SQLite will only request a recursive mutex in 5974** cases where it really needs one. If a faster non-recursive mutex 5975** implementation is available on the host platform, the mutex subsystem 5976** might return such a mutex in response to SQLITE_MUTEX_FAST. 5977** 5978** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 5979** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 5980** a pointer to a static preexisting mutex. ^Nine static mutexes are 5981** used by the current version of SQLite. Future versions of SQLite 5982** may add additional static mutexes. Static mutexes are for internal 5983** use by SQLite only. Applications that use SQLite mutexes should 5984** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 5985** SQLITE_MUTEX_RECURSIVE. 5986** 5987** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 5988** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 5989** returns a different mutex on every call. ^For the static 5990** mutex types, the same mutex is returned on every call that has 5991** the same type number. 5992** 5993** ^The sqlite3_mutex_free() routine deallocates a previously 5994** allocated dynamic mutex. Attempting to deallocate a static 5995** mutex results in undefined behavior. 5996** 5997** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 5998** to enter a mutex. ^If another thread is already within the mutex, 5999** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6000** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6001** upon successful entry. ^(Mutexes created using 6002** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6003** In such cases, the 6004** mutex must be exited an equal number of times before another thread 6005** can enter.)^ If the same thread tries to enter any mutex other 6006** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6007** 6008** ^(Some systems (for example, Windows 95) do not support the operation 6009** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6010** will always return SQLITE_BUSY. The SQLite core only ever uses 6011** sqlite3_mutex_try() as an optimization so this is acceptable 6012** behavior.)^ 6013** 6014** ^The sqlite3_mutex_leave() routine exits a mutex that was 6015** previously entered by the same thread. The behavior 6016** is undefined if the mutex is not currently entered by the 6017** calling thread or is not currently allocated. 6018** 6019** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6020** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6021** behave as no-ops. 6022** 6023** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6024*/ 6025sqlite3_mutex *sqlite3_mutex_alloc(int); 6026void sqlite3_mutex_free(sqlite3_mutex*); 6027void sqlite3_mutex_enter(sqlite3_mutex*); 6028int sqlite3_mutex_try(sqlite3_mutex*); 6029void sqlite3_mutex_leave(sqlite3_mutex*); 6030 6031/* 6032** CAPI3REF: Mutex Methods Object 6033** 6034** An instance of this structure defines the low-level routines 6035** used to allocate and use mutexes. 6036** 6037** Usually, the default mutex implementations provided by SQLite are 6038** sufficient, however the application has the option of substituting a custom 6039** implementation for specialized deployments or systems for which SQLite 6040** does not provide a suitable implementation. In this case, the application 6041** creates and populates an instance of this structure to pass 6042** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6043** Additionally, an instance of this structure can be used as an 6044** output variable when querying the system for the current mutex 6045** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6046** 6047** ^The xMutexInit method defined by this structure is invoked as 6048** part of system initialization by the sqlite3_initialize() function. 6049** ^The xMutexInit routine is called by SQLite exactly once for each 6050** effective call to [sqlite3_initialize()]. 6051** 6052** ^The xMutexEnd method defined by this structure is invoked as 6053** part of system shutdown by the sqlite3_shutdown() function. The 6054** implementation of this method is expected to release all outstanding 6055** resources obtained by the mutex methods implementation, especially 6056** those obtained by the xMutexInit method. ^The xMutexEnd() 6057** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6058** 6059** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6060** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6061** xMutexNotheld) implement the following interfaces (respectively): 6062** 6063** <ul> 6064** <li> [sqlite3_mutex_alloc()] </li> 6065** <li> [sqlite3_mutex_free()] </li> 6066** <li> [sqlite3_mutex_enter()] </li> 6067** <li> [sqlite3_mutex_try()] </li> 6068** <li> [sqlite3_mutex_leave()] </li> 6069** <li> [sqlite3_mutex_held()] </li> 6070** <li> [sqlite3_mutex_notheld()] </li> 6071** </ul>)^ 6072** 6073** The only difference is that the public sqlite3_XXX functions enumerated 6074** above silently ignore any invocations that pass a NULL pointer instead 6075** of a valid mutex handle. The implementations of the methods defined 6076** by this structure are not required to handle this case, the results 6077** of passing a NULL pointer instead of a valid mutex handle are undefined 6078** (i.e. it is acceptable to provide an implementation that segfaults if 6079** it is passed a NULL pointer). 6080** 6081** The xMutexInit() method must be threadsafe. It must be harmless to 6082** invoke xMutexInit() multiple times within the same process and without 6083** intervening calls to xMutexEnd(). Second and subsequent calls to 6084** xMutexInit() must be no-ops. 6085** 6086** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6087** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6088** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6089** memory allocation for a fast or recursive mutex. 6090** 6091** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6092** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6093** If xMutexInit fails in any way, it is expected to clean up after itself 6094** prior to returning. 6095*/ 6096typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6097struct sqlite3_mutex_methods { 6098 int (*xMutexInit)(void); 6099 int (*xMutexEnd)(void); 6100 sqlite3_mutex *(*xMutexAlloc)(int); 6101 void (*xMutexFree)(sqlite3_mutex *); 6102 void (*xMutexEnter)(sqlite3_mutex *); 6103 int (*xMutexTry)(sqlite3_mutex *); 6104 void (*xMutexLeave)(sqlite3_mutex *); 6105 int (*xMutexHeld)(sqlite3_mutex *); 6106 int (*xMutexNotheld)(sqlite3_mutex *); 6107}; 6108 6109/* 6110** CAPI3REF: Mutex Verification Routines 6111** 6112** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6113** are intended for use inside assert() statements. The SQLite core 6114** never uses these routines except inside an assert() and applications 6115** are advised to follow the lead of the core. The SQLite core only 6116** provides implementations for these routines when it is compiled 6117** with the SQLITE_DEBUG flag. External mutex implementations 6118** are only required to provide these routines if SQLITE_DEBUG is 6119** defined and if NDEBUG is not defined. 6120** 6121** These routines should return true if the mutex in their argument 6122** is held or not held, respectively, by the calling thread. 6123** 6124** The implementation is not required to provide versions of these 6125** routines that actually work. If the implementation does not provide working 6126** versions of these routines, it should at least provide stubs that always 6127** return true so that one does not get spurious assertion failures. 6128** 6129** If the argument to sqlite3_mutex_held() is a NULL pointer then 6130** the routine should return 1. This seems counter-intuitive since 6131** clearly the mutex cannot be held if it does not exist. But 6132** the reason the mutex does not exist is because the build is not 6133** using mutexes. And we do not want the assert() containing the 6134** call to sqlite3_mutex_held() to fail, so a non-zero return is 6135** the appropriate thing to do. The sqlite3_mutex_notheld() 6136** interface should also return 1 when given a NULL pointer. 6137*/ 6138#ifndef NDEBUG 6139int sqlite3_mutex_held(sqlite3_mutex*); 6140int sqlite3_mutex_notheld(sqlite3_mutex*); 6141#endif 6142 6143/* 6144** CAPI3REF: Mutex Types 6145** 6146** The [sqlite3_mutex_alloc()] interface takes a single argument 6147** which is one of these integer constants. 6148** 6149** The set of static mutexes may change from one SQLite release to the 6150** next. Applications that override the built-in mutex logic must be 6151** prepared to accommodate additional static mutexes. 6152*/ 6153#define SQLITE_MUTEX_FAST 0 6154#define SQLITE_MUTEX_RECURSIVE 1 6155#define SQLITE_MUTEX_STATIC_MASTER 2 6156#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6157#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6158#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6159#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 6160#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6161#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6162#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6163#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6164#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6165#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6166 6167/* 6168** CAPI3REF: Retrieve the mutex for a database connection 6169** 6170** ^This interface returns a pointer the [sqlite3_mutex] object that 6171** serializes access to the [database connection] given in the argument 6172** when the [threading mode] is Serialized. 6173** ^If the [threading mode] is Single-thread or Multi-thread then this 6174** routine returns a NULL pointer. 6175*/ 6176sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 6177 6178/* 6179** CAPI3REF: Low-Level Control Of Database Files 6180** 6181** ^The [sqlite3_file_control()] interface makes a direct call to the 6182** xFileControl method for the [sqlite3_io_methods] object associated 6183** with a particular database identified by the second argument. ^The 6184** name of the database is "main" for the main database or "temp" for the 6185** TEMP database, or the name that appears after the AS keyword for 6186** databases that are added using the [ATTACH] SQL command. 6187** ^A NULL pointer can be used in place of "main" to refer to the 6188** main database file. 6189** ^The third and fourth parameters to this routine 6190** are passed directly through to the second and third parameters of 6191** the xFileControl method. ^The return value of the xFileControl 6192** method becomes the return value of this routine. 6193** 6194** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 6195** a pointer to the underlying [sqlite3_file] object to be written into 6196** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 6197** case is a short-circuit path which does not actually invoke the 6198** underlying sqlite3_io_methods.xFileControl method. 6199** 6200** ^If the second parameter (zDbName) does not match the name of any 6201** open database file, then SQLITE_ERROR is returned. ^This error 6202** code is not remembered and will not be recalled by [sqlite3_errcode()] 6203** or [sqlite3_errmsg()]. The underlying xFileControl method might 6204** also return SQLITE_ERROR. There is no way to distinguish between 6205** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6206** xFileControl method. 6207** 6208** See also: [SQLITE_FCNTL_LOCKSTATE] 6209*/ 6210int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6211 6212/* 6213** CAPI3REF: Testing Interface 6214** 6215** ^The sqlite3_test_control() interface is used to read out internal 6216** state of SQLite and to inject faults into SQLite for testing 6217** purposes. ^The first parameter is an operation code that determines 6218** the number, meaning, and operation of all subsequent parameters. 6219** 6220** This interface is not for use by applications. It exists solely 6221** for verifying the correct operation of the SQLite library. Depending 6222** on how the SQLite library is compiled, this interface might not exist. 6223** 6224** The details of the operation codes, their meanings, the parameters 6225** they take, and what they do are all subject to change without notice. 6226** Unlike most of the SQLite API, this function is not guaranteed to 6227** operate consistently from one release to the next. 6228*/ 6229int sqlite3_test_control(int op, ...); 6230 6231/* 6232** CAPI3REF: Testing Interface Operation Codes 6233** 6234** These constants are the valid operation code parameters used 6235** as the first argument to [sqlite3_test_control()]. 6236** 6237** These parameters and their meanings are subject to change 6238** without notice. These values are for testing purposes only. 6239** Applications should not use any of these parameters or the 6240** [sqlite3_test_control()] interface. 6241*/ 6242#define SQLITE_TESTCTRL_FIRST 5 6243#define SQLITE_TESTCTRL_PRNG_SAVE 5 6244#define SQLITE_TESTCTRL_PRNG_RESTORE 6 6245#define SQLITE_TESTCTRL_PRNG_RESET 7 6246#define SQLITE_TESTCTRL_BITVEC_TEST 8 6247#define SQLITE_TESTCTRL_FAULT_INSTALL 9 6248#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 6249#define SQLITE_TESTCTRL_PENDING_BYTE 11 6250#define SQLITE_TESTCTRL_ASSERT 12 6251#define SQLITE_TESTCTRL_ALWAYS 13 6252#define SQLITE_TESTCTRL_RESERVE 14 6253#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 6254#define SQLITE_TESTCTRL_ISKEYWORD 16 6255#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 6256#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 6257#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 6258#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 6259#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 6260#define SQLITE_TESTCTRL_BYTEORDER 22 6261#define SQLITE_TESTCTRL_ISINIT 23 6262#define SQLITE_TESTCTRL_SORTER_MMAP 24 6263#define SQLITE_TESTCTRL_LAST 24 6264 6265/* 6266** CAPI3REF: SQLite Runtime Status 6267** 6268** ^This interface is used to retrieve runtime status information 6269** about the performance of SQLite, and optionally to reset various 6270** highwater marks. ^The first argument is an integer code for 6271** the specific parameter to measure. ^(Recognized integer codes 6272** are of the form [status parameters | SQLITE_STATUS_...].)^ 6273** ^The current value of the parameter is returned into *pCurrent. 6274** ^The highest recorded value is returned in *pHighwater. ^If the 6275** resetFlag is true, then the highest record value is reset after 6276** *pHighwater is written. ^(Some parameters do not record the highest 6277** value. For those parameters 6278** nothing is written into *pHighwater and the resetFlag is ignored.)^ 6279** ^(Other parameters record only the highwater mark and not the current 6280** value. For these latter parameters nothing is written into *pCurrent.)^ 6281** 6282** ^The sqlite3_status() routine returns SQLITE_OK on success and a 6283** non-zero [error code] on failure. 6284** 6285** This routine is threadsafe but is not atomic. This routine can be 6286** called while other threads are running the same or different SQLite 6287** interfaces. However the values returned in *pCurrent and 6288** *pHighwater reflect the status of SQLite at different points in time 6289** and it is possible that another thread might change the parameter 6290** in between the times when *pCurrent and *pHighwater are written. 6291** 6292** See also: [sqlite3_db_status()] 6293*/ 6294int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 6295 6296 6297/* 6298** CAPI3REF: Status Parameters 6299** KEYWORDS: {status parameters} 6300** 6301** These integer constants designate various run-time status parameters 6302** that can be returned by [sqlite3_status()]. 6303** 6304** <dl> 6305** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 6306** <dd>This parameter is the current amount of memory checked out 6307** using [sqlite3_malloc()], either directly or indirectly. The 6308** figure includes calls made to [sqlite3_malloc()] by the application 6309** and internal memory usage by the SQLite library. Scratch memory 6310** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 6311** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 6312** this parameter. The amount returned is the sum of the allocation 6313** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 6314** 6315** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 6316** <dd>This parameter records the largest memory allocation request 6317** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 6318** internal equivalents). Only the value returned in the 6319** *pHighwater parameter to [sqlite3_status()] is of interest. 6320** The value written into the *pCurrent parameter is undefined.</dd>)^ 6321** 6322** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 6323** <dd>This parameter records the number of separate memory allocations 6324** currently checked out.</dd>)^ 6325** 6326** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 6327** <dd>This parameter returns the number of pages used out of the 6328** [pagecache memory allocator] that was configured using 6329** [SQLITE_CONFIG_PAGECACHE]. The 6330** value returned is in pages, not in bytes.</dd>)^ 6331** 6332** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 6333** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 6334** <dd>This parameter returns the number of bytes of page cache 6335** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 6336** buffer and where forced to overflow to [sqlite3_malloc()]. The 6337** returned value includes allocations that overflowed because they 6338** where too large (they were larger than the "sz" parameter to 6339** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 6340** no space was left in the page cache.</dd>)^ 6341** 6342** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 6343** <dd>This parameter records the largest memory allocation request 6344** handed to [pagecache memory allocator]. Only the value returned in the 6345** *pHighwater parameter to [sqlite3_status()] is of interest. 6346** The value written into the *pCurrent parameter is undefined.</dd>)^ 6347** 6348** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 6349** <dd>This parameter returns the number of allocations used out of the 6350** [scratch memory allocator] configured using 6351** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 6352** in bytes. Since a single thread may only have one scratch allocation 6353** outstanding at time, this parameter also reports the number of threads 6354** using scratch memory at the same time.</dd>)^ 6355** 6356** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 6357** <dd>This parameter returns the number of bytes of scratch memory 6358** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 6359** buffer and where forced to overflow to [sqlite3_malloc()]. The values 6360** returned include overflows because the requested allocation was too 6361** larger (that is, because the requested allocation was larger than the 6362** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 6363** slots were available. 6364** </dd>)^ 6365** 6366** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 6367** <dd>This parameter records the largest memory allocation request 6368** handed to [scratch memory allocator]. Only the value returned in the 6369** *pHighwater parameter to [sqlite3_status()] is of interest. 6370** The value written into the *pCurrent parameter is undefined.</dd>)^ 6371** 6372** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 6373** <dd>This parameter records the deepest parser stack. It is only 6374** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 6375** </dl> 6376** 6377** New status parameters may be added from time to time. 6378*/ 6379#define SQLITE_STATUS_MEMORY_USED 0 6380#define SQLITE_STATUS_PAGECACHE_USED 1 6381#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 6382#define SQLITE_STATUS_SCRATCH_USED 3 6383#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 6384#define SQLITE_STATUS_MALLOC_SIZE 5 6385#define SQLITE_STATUS_PARSER_STACK 6 6386#define SQLITE_STATUS_PAGECACHE_SIZE 7 6387#define SQLITE_STATUS_SCRATCH_SIZE 8 6388#define SQLITE_STATUS_MALLOC_COUNT 9 6389 6390/* 6391** CAPI3REF: Database Connection Status 6392** 6393** ^This interface is used to retrieve runtime status information 6394** about a single [database connection]. ^The first argument is the 6395** database connection object to be interrogated. ^The second argument 6396** is an integer constant, taken from the set of 6397** [SQLITE_DBSTATUS options], that 6398** determines the parameter to interrogate. The set of 6399** [SQLITE_DBSTATUS options] is likely 6400** to grow in future releases of SQLite. 6401** 6402** ^The current value of the requested parameter is written into *pCur 6403** and the highest instantaneous value is written into *pHiwtr. ^If 6404** the resetFlg is true, then the highest instantaneous value is 6405** reset back down to the current value. 6406** 6407** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 6408** non-zero [error code] on failure. 6409** 6410** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 6411*/ 6412int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 6413 6414/* 6415** CAPI3REF: Status Parameters for database connections 6416** KEYWORDS: {SQLITE_DBSTATUS options} 6417** 6418** These constants are the available integer "verbs" that can be passed as 6419** the second argument to the [sqlite3_db_status()] interface. 6420** 6421** New verbs may be added in future releases of SQLite. Existing verbs 6422** might be discontinued. Applications should check the return code from 6423** [sqlite3_db_status()] to make sure that the call worked. 6424** The [sqlite3_db_status()] interface will return a non-zero error code 6425** if a discontinued or unsupported verb is invoked. 6426** 6427** <dl> 6428** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 6429** <dd>This parameter returns the number of lookaside memory slots currently 6430** checked out.</dd>)^ 6431** 6432** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 6433** <dd>This parameter returns the number malloc attempts that were 6434** satisfied using lookaside memory. Only the high-water value is meaningful; 6435** the current value is always zero.)^ 6436** 6437** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 6438** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 6439** <dd>This parameter returns the number malloc attempts that might have 6440** been satisfied using lookaside memory but failed due to the amount of 6441** memory requested being larger than the lookaside slot size. 6442** Only the high-water value is meaningful; 6443** the current value is always zero.)^ 6444** 6445** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 6446** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 6447** <dd>This parameter returns the number malloc attempts that might have 6448** been satisfied using lookaside memory but failed due to all lookaside 6449** memory already being in use. 6450** Only the high-water value is meaningful; 6451** the current value is always zero.)^ 6452** 6453** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 6454** <dd>This parameter returns the approximate number of bytes of heap 6455** memory used by all pager caches associated with the database connection.)^ 6456** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 6457** 6458** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 6459** <dd>This parameter returns the approximate number of bytes of heap 6460** memory used to store the schema for all databases associated 6461** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 6462** ^The full amount of memory used by the schemas is reported, even if the 6463** schema memory is shared with other database connections due to 6464** [shared cache mode] being enabled. 6465** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 6466** 6467** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 6468** <dd>This parameter returns the approximate number of bytes of heap 6469** and lookaside memory used by all prepared statements associated with 6470** the database connection.)^ 6471** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 6472** </dd> 6473** 6474** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 6475** <dd>This parameter returns the number of pager cache hits that have 6476** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 6477** is always 0. 6478** </dd> 6479** 6480** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6481** <dd>This parameter returns the number of pager cache misses that have 6482** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6483** is always 0. 6484** </dd> 6485** 6486** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 6487** <dd>This parameter returns the number of dirty cache entries that have 6488** been written to disk. Specifically, the number of pages written to the 6489** wal file in wal mode databases, or the number of pages written to the 6490** database file in rollback mode databases. Any pages written as part of 6491** transaction rollback or database recovery operations are not included. 6492** If an IO or other error occurs while writing a page to disk, the effect 6493** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 6494** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 6495** </dd> 6496** 6497** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 6498** <dd>This parameter returns zero for the current value if and only if 6499** all foreign key constraints (deferred or immediate) have been 6500** resolved.)^ ^The highwater mark is always 0. 6501** </dd> 6502** </dl> 6503*/ 6504#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6505#define SQLITE_DBSTATUS_CACHE_USED 1 6506#define SQLITE_DBSTATUS_SCHEMA_USED 2 6507#define SQLITE_DBSTATUS_STMT_USED 3 6508#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6509#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6510#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 6511#define SQLITE_DBSTATUS_CACHE_HIT 7 6512#define SQLITE_DBSTATUS_CACHE_MISS 8 6513#define SQLITE_DBSTATUS_CACHE_WRITE 9 6514#define SQLITE_DBSTATUS_DEFERRED_FKS 10 6515#define SQLITE_DBSTATUS_MAX 10 /* Largest defined DBSTATUS */ 6516 6517 6518/* 6519** CAPI3REF: Prepared Statement Status 6520** 6521** ^(Each prepared statement maintains various 6522** [SQLITE_STMTSTATUS counters] that measure the number 6523** of times it has performed specific operations.)^ These counters can 6524** be used to monitor the performance characteristics of the prepared 6525** statements. For example, if the number of table steps greatly exceeds 6526** the number of table searches or result rows, that would tend to indicate 6527** that the prepared statement is using a full table scan rather than 6528** an index. 6529** 6530** ^(This interface is used to retrieve and reset counter values from 6531** a [prepared statement]. The first argument is the prepared statement 6532** object to be interrogated. The second argument 6533** is an integer code for a specific [SQLITE_STMTSTATUS counter] 6534** to be interrogated.)^ 6535** ^The current value of the requested counter is returned. 6536** ^If the resetFlg is true, then the counter is reset to zero after this 6537** interface call returns. 6538** 6539** See also: [sqlite3_status()] and [sqlite3_db_status()]. 6540*/ 6541int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 6542 6543/* 6544** CAPI3REF: Status Parameters for prepared statements 6545** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 6546** 6547** These preprocessor macros define integer codes that name counter 6548** values associated with the [sqlite3_stmt_status()] interface. 6549** The meanings of the various counters are as follows: 6550** 6551** <dl> 6552** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 6553** <dd>^This is the number of times that SQLite has stepped forward in 6554** a table as part of a full table scan. Large numbers for this counter 6555** may indicate opportunities for performance improvement through 6556** careful use of indices.</dd> 6557** 6558** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 6559** <dd>^This is the number of sort operations that have occurred. 6560** A non-zero value in this counter may indicate an opportunity to 6561** improvement performance through careful use of indices.</dd> 6562** 6563** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 6564** <dd>^This is the number of rows inserted into transient indices that 6565** were created automatically in order to help joins run faster. 6566** A non-zero value in this counter may indicate an opportunity to 6567** improvement performance by adding permanent indices that do not 6568** need to be reinitialized each time the statement is run.</dd> 6569** 6570** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 6571** <dd>^This is the number of virtual machine operations executed 6572** by the prepared statement if that number is less than or equal 6573** to 2147483647. The number of virtual machine operations can be 6574** used as a proxy for the total work done by the prepared statement. 6575** If the number of virtual machine operations exceeds 2147483647 6576** then the value returned by this statement status code is undefined. 6577** </dd> 6578** </dl> 6579*/ 6580#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 6581#define SQLITE_STMTSTATUS_SORT 2 6582#define SQLITE_STMTSTATUS_AUTOINDEX 3 6583#define SQLITE_STMTSTATUS_VM_STEP 4 6584 6585/* 6586** CAPI3REF: Custom Page Cache Object 6587** 6588** The sqlite3_pcache type is opaque. It is implemented by 6589** the pluggable module. The SQLite core has no knowledge of 6590** its size or internal structure and never deals with the 6591** sqlite3_pcache object except by holding and passing pointers 6592** to the object. 6593** 6594** See [sqlite3_pcache_methods2] for additional information. 6595*/ 6596typedef struct sqlite3_pcache sqlite3_pcache; 6597 6598/* 6599** CAPI3REF: Custom Page Cache Object 6600** 6601** The sqlite3_pcache_page object represents a single page in the 6602** page cache. The page cache will allocate instances of this 6603** object. Various methods of the page cache use pointers to instances 6604** of this object as parameters or as their return value. 6605** 6606** See [sqlite3_pcache_methods2] for additional information. 6607*/ 6608typedef struct sqlite3_pcache_page sqlite3_pcache_page; 6609struct sqlite3_pcache_page { 6610 void *pBuf; /* The content of the page */ 6611 void *pExtra; /* Extra information associated with the page */ 6612}; 6613 6614/* 6615** CAPI3REF: Application Defined Page Cache. 6616** KEYWORDS: {page cache} 6617** 6618** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 6619** register an alternative page cache implementation by passing in an 6620** instance of the sqlite3_pcache_methods2 structure.)^ 6621** In many applications, most of the heap memory allocated by 6622** SQLite is used for the page cache. 6623** By implementing a 6624** custom page cache using this API, an application can better control 6625** the amount of memory consumed by SQLite, the way in which 6626** that memory is allocated and released, and the policies used to 6627** determine exactly which parts of a database file are cached and for 6628** how long. 6629** 6630** The alternative page cache mechanism is an 6631** extreme measure that is only needed by the most demanding applications. 6632** The built-in page cache is recommended for most uses. 6633** 6634** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 6635** internal buffer by SQLite within the call to [sqlite3_config]. Hence 6636** the application may discard the parameter after the call to 6637** [sqlite3_config()] returns.)^ 6638** 6639** [[the xInit() page cache method]] 6640** ^(The xInit() method is called once for each effective 6641** call to [sqlite3_initialize()])^ 6642** (usually only once during the lifetime of the process). ^(The xInit() 6643** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 6644** The intent of the xInit() method is to set up global data structures 6645** required by the custom page cache implementation. 6646** ^(If the xInit() method is NULL, then the 6647** built-in default page cache is used instead of the application defined 6648** page cache.)^ 6649** 6650** [[the xShutdown() page cache method]] 6651** ^The xShutdown() method is called by [sqlite3_shutdown()]. 6652** It can be used to clean up 6653** any outstanding resources before process shutdown, if required. 6654** ^The xShutdown() method may be NULL. 6655** 6656** ^SQLite automatically serializes calls to the xInit method, 6657** so the xInit method need not be threadsafe. ^The 6658** xShutdown method is only called from [sqlite3_shutdown()] so it does 6659** not need to be threadsafe either. All other methods must be threadsafe 6660** in multithreaded applications. 6661** 6662** ^SQLite will never invoke xInit() more than once without an intervening 6663** call to xShutdown(). 6664** 6665** [[the xCreate() page cache methods]] 6666** ^SQLite invokes the xCreate() method to construct a new cache instance. 6667** SQLite will typically create one cache instance for each open database file, 6668** though this is not guaranteed. ^The 6669** first parameter, szPage, is the size in bytes of the pages that must 6670** be allocated by the cache. ^szPage will always a power of two. ^The 6671** second parameter szExtra is a number of bytes of extra storage 6672** associated with each page cache entry. ^The szExtra parameter will 6673** a number less than 250. SQLite will use the 6674** extra szExtra bytes on each page to store metadata about the underlying 6675** database page on disk. The value passed into szExtra depends 6676** on the SQLite version, the target platform, and how SQLite was compiled. 6677** ^The third argument to xCreate(), bPurgeable, is true if the cache being 6678** created will be used to cache database pages of a file stored on disk, or 6679** false if it is used for an in-memory database. The cache implementation 6680** does not have to do anything special based with the value of bPurgeable; 6681** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 6682** never invoke xUnpin() except to deliberately delete a page. 6683** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 6684** false will always have the "discard" flag set to true. 6685** ^Hence, a cache created with bPurgeable false will 6686** never contain any unpinned pages. 6687** 6688** [[the xCachesize() page cache method]] 6689** ^(The xCachesize() method may be called at any time by SQLite to set the 6690** suggested maximum cache-size (number of pages stored by) the cache 6691** instance passed as the first argument. This is the value configured using 6692** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 6693** parameter, the implementation is not required to do anything with this 6694** value; it is advisory only. 6695** 6696** [[the xPagecount() page cache methods]] 6697** The xPagecount() method must return the number of pages currently 6698** stored in the cache, both pinned and unpinned. 6699** 6700** [[the xFetch() page cache methods]] 6701** The xFetch() method locates a page in the cache and returns a pointer to 6702** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 6703** The pBuf element of the returned sqlite3_pcache_page object will be a 6704** pointer to a buffer of szPage bytes used to store the content of a 6705** single database page. The pExtra element of sqlite3_pcache_page will be 6706** a pointer to the szExtra bytes of extra storage that SQLite has requested 6707** for each entry in the page cache. 6708** 6709** The page to be fetched is determined by the key. ^The minimum key value 6710** is 1. After it has been retrieved using xFetch, the page is considered 6711** to be "pinned". 6712** 6713** If the requested page is already in the page cache, then the page cache 6714** implementation must return a pointer to the page buffer with its content 6715** intact. If the requested page is not already in the cache, then the 6716** cache implementation should use the value of the createFlag 6717** parameter to help it determined what action to take: 6718** 6719** <table border=1 width=85% align=center> 6720** <tr><th> createFlag <th> Behavior when page is not already in cache 6721** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6722** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6723** Otherwise return NULL. 6724** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6725** NULL if allocating a new page is effectively impossible. 6726** </table> 6727** 6728** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6729** will only use a createFlag of 2 after a prior call with a createFlag of 1 6730** failed.)^ In between the to xFetch() calls, SQLite may 6731** attempt to unpin one or more cache pages by spilling the content of 6732** pinned pages to disk and synching the operating system disk cache. 6733** 6734** [[the xUnpin() page cache method]] 6735** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6736** as its second argument. If the third parameter, discard, is non-zero, 6737** then the page must be evicted from the cache. 6738** ^If the discard parameter is 6739** zero, then the page may be discarded or retained at the discretion of 6740** page cache implementation. ^The page cache implementation 6741** may choose to evict unpinned pages at any time. 6742** 6743** The cache must not perform any reference counting. A single 6744** call to xUnpin() unpins the page regardless of the number of prior calls 6745** to xFetch(). 6746** 6747** [[the xRekey() page cache methods]] 6748** The xRekey() method is used to change the key value associated with the 6749** page passed as the second argument. If the cache 6750** previously contains an entry associated with newKey, it must be 6751** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6752** to be pinned. 6753** 6754** When SQLite calls the xTruncate() method, the cache must discard all 6755** existing cache entries with page numbers (keys) greater than or equal 6756** to the value of the iLimit parameter passed to xTruncate(). If any 6757** of these pages are pinned, they are implicitly unpinned, meaning that 6758** they can be safely discarded. 6759** 6760** [[the xDestroy() page cache method]] 6761** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6762** All resources associated with the specified cache should be freed. ^After 6763** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6764** handle invalid, and will not use it with any other sqlite3_pcache_methods2 6765** functions. 6766** 6767** [[the xShrink() page cache method]] 6768** ^SQLite invokes the xShrink() method when it wants the page cache to 6769** free up as much of heap memory as possible. The page cache implementation 6770** is not obligated to free any memory, but well-behaved implementations should 6771** do their best. 6772*/ 6773typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 6774struct sqlite3_pcache_methods2 { 6775 int iVersion; 6776 void *pArg; 6777 int (*xInit)(void*); 6778 void (*xShutdown)(void*); 6779 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 6780 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6781 int (*xPagecount)(sqlite3_pcache*); 6782 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6783 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 6784 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 6785 unsigned oldKey, unsigned newKey); 6786 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6787 void (*xDestroy)(sqlite3_pcache*); 6788 void (*xShrink)(sqlite3_pcache*); 6789}; 6790 6791/* 6792** This is the obsolete pcache_methods object that has now been replaced 6793** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 6794** retained in the header file for backwards compatibility only. 6795*/ 6796typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 6797struct sqlite3_pcache_methods { 6798 void *pArg; 6799 int (*xInit)(void*); 6800 void (*xShutdown)(void*); 6801 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 6802 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6803 int (*xPagecount)(sqlite3_pcache*); 6804 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6805 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 6806 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 6807 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6808 void (*xDestroy)(sqlite3_pcache*); 6809}; 6810 6811 6812/* 6813** CAPI3REF: Online Backup Object 6814** 6815** The sqlite3_backup object records state information about an ongoing 6816** online backup operation. ^The sqlite3_backup object is created by 6817** a call to [sqlite3_backup_init()] and is destroyed by a call to 6818** [sqlite3_backup_finish()]. 6819** 6820** See Also: [Using the SQLite Online Backup API] 6821*/ 6822typedef struct sqlite3_backup sqlite3_backup; 6823 6824/* 6825** CAPI3REF: Online Backup API. 6826** 6827** The backup API copies the content of one database into another. 6828** It is useful either for creating backups of databases or 6829** for copying in-memory databases to or from persistent files. 6830** 6831** See Also: [Using the SQLite Online Backup API] 6832** 6833** ^SQLite holds a write transaction open on the destination database file 6834** for the duration of the backup operation. 6835** ^The source database is read-locked only while it is being read; 6836** it is not locked continuously for the entire backup operation. 6837** ^Thus, the backup may be performed on a live source database without 6838** preventing other database connections from 6839** reading or writing to the source database while the backup is underway. 6840** 6841** ^(To perform a backup operation: 6842** <ol> 6843** <li><b>sqlite3_backup_init()</b> is called once to initialize the 6844** backup, 6845** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 6846** the data between the two databases, and finally 6847** <li><b>sqlite3_backup_finish()</b> is called to release all resources 6848** associated with the backup operation. 6849** </ol>)^ 6850** There should be exactly one call to sqlite3_backup_finish() for each 6851** successful call to sqlite3_backup_init(). 6852** 6853** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 6854** 6855** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 6856** [database connection] associated with the destination database 6857** and the database name, respectively. 6858** ^The database name is "main" for the main database, "temp" for the 6859** temporary database, or the name specified after the AS keyword in 6860** an [ATTACH] statement for an attached database. 6861** ^The S and M arguments passed to 6862** sqlite3_backup_init(D,N,S,M) identify the [database connection] 6863** and database name of the source database, respectively. 6864** ^The source and destination [database connections] (parameters S and D) 6865** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 6866** an error. 6867** 6868** ^A call to sqlite3_backup_init() will fail, returning SQLITE_ERROR, if 6869** there is already a read or read-write transaction open on the 6870** destination database. 6871** 6872** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 6873** returned and an error code and error message are stored in the 6874** destination [database connection] D. 6875** ^The error code and message for the failed call to sqlite3_backup_init() 6876** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 6877** [sqlite3_errmsg16()] functions. 6878** ^A successful call to sqlite3_backup_init() returns a pointer to an 6879** [sqlite3_backup] object. 6880** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 6881** sqlite3_backup_finish() functions to perform the specified backup 6882** operation. 6883** 6884** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 6885** 6886** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 6887** the source and destination databases specified by [sqlite3_backup] object B. 6888** ^If N is negative, all remaining source pages are copied. 6889** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 6890** are still more pages to be copied, then the function returns [SQLITE_OK]. 6891** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 6892** from source to destination, then it returns [SQLITE_DONE]. 6893** ^If an error occurs while running sqlite3_backup_step(B,N), 6894** then an [error code] is returned. ^As well as [SQLITE_OK] and 6895** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 6896** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 6897** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 6898** 6899** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 6900** <ol> 6901** <li> the destination database was opened read-only, or 6902** <li> the destination database is using write-ahead-log journaling 6903** and the destination and source page sizes differ, or 6904** <li> the destination database is an in-memory database and the 6905** destination and source page sizes differ. 6906** </ol>)^ 6907** 6908** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 6909** the [sqlite3_busy_handler | busy-handler function] 6910** is invoked (if one is specified). ^If the 6911** busy-handler returns non-zero before the lock is available, then 6912** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 6913** sqlite3_backup_step() can be retried later. ^If the source 6914** [database connection] 6915** is being used to write to the source database when sqlite3_backup_step() 6916** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 6917** case the call to sqlite3_backup_step() can be retried later on. ^(If 6918** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 6919** [SQLITE_READONLY] is returned, then 6920** there is no point in retrying the call to sqlite3_backup_step(). These 6921** errors are considered fatal.)^ The application must accept 6922** that the backup operation has failed and pass the backup operation handle 6923** to the sqlite3_backup_finish() to release associated resources. 6924** 6925** ^The first call to sqlite3_backup_step() obtains an exclusive lock 6926** on the destination file. ^The exclusive lock is not released until either 6927** sqlite3_backup_finish() is called or the backup operation is complete 6928** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 6929** sqlite3_backup_step() obtains a [shared lock] on the source database that 6930** lasts for the duration of the sqlite3_backup_step() call. 6931** ^Because the source database is not locked between calls to 6932** sqlite3_backup_step(), the source database may be modified mid-way 6933** through the backup process. ^If the source database is modified by an 6934** external process or via a database connection other than the one being 6935** used by the backup operation, then the backup will be automatically 6936** restarted by the next call to sqlite3_backup_step(). ^If the source 6937** database is modified by the using the same database connection as is used 6938** by the backup operation, then the backup database is automatically 6939** updated at the same time. 6940** 6941** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 6942** 6943** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 6944** application wishes to abandon the backup operation, the application 6945** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 6946** ^The sqlite3_backup_finish() interfaces releases all 6947** resources associated with the [sqlite3_backup] object. 6948** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 6949** active write-transaction on the destination database is rolled back. 6950** The [sqlite3_backup] object is invalid 6951** and may not be used following a call to sqlite3_backup_finish(). 6952** 6953** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 6954** sqlite3_backup_step() errors occurred, regardless or whether or not 6955** sqlite3_backup_step() completed. 6956** ^If an out-of-memory condition or IO error occurred during any prior 6957** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 6958** sqlite3_backup_finish() returns the corresponding [error code]. 6959** 6960** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 6961** is not a permanent error and does not affect the return value of 6962** sqlite3_backup_finish(). 6963** 6964** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]] 6965** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 6966** 6967** ^Each call to sqlite3_backup_step() sets two values inside 6968** the [sqlite3_backup] object: the number of pages still to be backed 6969** up and the total number of pages in the source database file. 6970** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 6971** retrieve these two values, respectively. 6972** 6973** ^The values returned by these functions are only updated by 6974** sqlite3_backup_step(). ^If the source database is modified during a backup 6975** operation, then the values are not updated to account for any extra 6976** pages that need to be updated or the size of the source database file 6977** changing. 6978** 6979** <b>Concurrent Usage of Database Handles</b> 6980** 6981** ^The source [database connection] may be used by the application for other 6982** purposes while a backup operation is underway or being initialized. 6983** ^If SQLite is compiled and configured to support threadsafe database 6984** connections, then the source database connection may be used concurrently 6985** from within other threads. 6986** 6987** However, the application must guarantee that the destination 6988** [database connection] is not passed to any other API (by any thread) after 6989** sqlite3_backup_init() is called and before the corresponding call to 6990** sqlite3_backup_finish(). SQLite does not currently check to see 6991** if the application incorrectly accesses the destination [database connection] 6992** and so no error code is reported, but the operations may malfunction 6993** nevertheless. Use of the destination database connection while a 6994** backup is in progress might also also cause a mutex deadlock. 6995** 6996** If running in [shared cache mode], the application must 6997** guarantee that the shared cache used by the destination database 6998** is not accessed while the backup is running. In practice this means 6999** that the application must guarantee that the disk file being 7000** backed up to is not accessed by any connection within the process, 7001** not just the specific connection that was passed to sqlite3_backup_init(). 7002** 7003** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7004** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7005** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7006** APIs are not strictly speaking threadsafe. If they are invoked at the 7007** same time as another thread is invoking sqlite3_backup_step() it is 7008** possible that they return invalid values. 7009*/ 7010sqlite3_backup *sqlite3_backup_init( 7011 sqlite3 *pDest, /* Destination database handle */ 7012 const char *zDestName, /* Destination database name */ 7013 sqlite3 *pSource, /* Source database handle */ 7014 const char *zSourceName /* Source database name */ 7015); 7016int sqlite3_backup_step(sqlite3_backup *p, int nPage); 7017int sqlite3_backup_finish(sqlite3_backup *p); 7018int sqlite3_backup_remaining(sqlite3_backup *p); 7019int sqlite3_backup_pagecount(sqlite3_backup *p); 7020 7021/* 7022** CAPI3REF: Unlock Notification 7023** 7024** ^When running in shared-cache mode, a database operation may fail with 7025** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7026** individual tables within the shared-cache cannot be obtained. See 7027** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7028** ^This API may be used to register a callback that SQLite will invoke 7029** when the connection currently holding the required lock relinquishes it. 7030** ^This API is only available if the library was compiled with the 7031** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7032** 7033** See Also: [Using the SQLite Unlock Notification Feature]. 7034** 7035** ^Shared-cache locks are released when a database connection concludes 7036** its current transaction, either by committing it or rolling it back. 7037** 7038** ^When a connection (known as the blocked connection) fails to obtain a 7039** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7040** identity of the database connection (the blocking connection) that 7041** has locked the required resource is stored internally. ^After an 7042** application receives an SQLITE_LOCKED error, it may call the 7043** sqlite3_unlock_notify() method with the blocked connection handle as 7044** the first argument to register for a callback that will be invoked 7045** when the blocking connections current transaction is concluded. ^The 7046** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7047** call that concludes the blocking connections transaction. 7048** 7049** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7050** there is a chance that the blocking connection will have already 7051** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7052** If this happens, then the specified callback is invoked immediately, 7053** from within the call to sqlite3_unlock_notify().)^ 7054** 7055** ^If the blocked connection is attempting to obtain a write-lock on a 7056** shared-cache table, and more than one other connection currently holds 7057** a read-lock on the same table, then SQLite arbitrarily selects one of 7058** the other connections to use as the blocking connection. 7059** 7060** ^(There may be at most one unlock-notify callback registered by a 7061** blocked connection. If sqlite3_unlock_notify() is called when the 7062** blocked connection already has a registered unlock-notify callback, 7063** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7064** called with a NULL pointer as its second argument, then any existing 7065** unlock-notify callback is canceled. ^The blocked connections 7066** unlock-notify callback may also be canceled by closing the blocked 7067** connection using [sqlite3_close()]. 7068** 7069** The unlock-notify callback is not reentrant. If an application invokes 7070** any sqlite3_xxx API functions from within an unlock-notify callback, a 7071** crash or deadlock may be the result. 7072** 7073** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7074** returns SQLITE_OK. 7075** 7076** <b>Callback Invocation Details</b> 7077** 7078** When an unlock-notify callback is registered, the application provides a 7079** single void* pointer that is passed to the callback when it is invoked. 7080** However, the signature of the callback function allows SQLite to pass 7081** it an array of void* context pointers. The first argument passed to 7082** an unlock-notify callback is a pointer to an array of void* pointers, 7083** and the second is the number of entries in the array. 7084** 7085** When a blocking connections transaction is concluded, there may be 7086** more than one blocked connection that has registered for an unlock-notify 7087** callback. ^If two or more such blocked connections have specified the 7088** same callback function, then instead of invoking the callback function 7089** multiple times, it is invoked once with the set of void* context pointers 7090** specified by the blocked connections bundled together into an array. 7091** This gives the application an opportunity to prioritize any actions 7092** related to the set of unblocked database connections. 7093** 7094** <b>Deadlock Detection</b> 7095** 7096** Assuming that after registering for an unlock-notify callback a 7097** database waits for the callback to be issued before taking any further 7098** action (a reasonable assumption), then using this API may cause the 7099** application to deadlock. For example, if connection X is waiting for 7100** connection Y's transaction to be concluded, and similarly connection 7101** Y is waiting on connection X's transaction, then neither connection 7102** will proceed and the system may remain deadlocked indefinitely. 7103** 7104** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7105** detection. ^If a given call to sqlite3_unlock_notify() would put the 7106** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7107** unlock-notify callback is registered. The system is said to be in 7108** a deadlocked state if connection A has registered for an unlock-notify 7109** callback on the conclusion of connection B's transaction, and connection 7110** B has itself registered for an unlock-notify callback when connection 7111** A's transaction is concluded. ^Indirect deadlock is also detected, so 7112** the system is also considered to be deadlocked if connection B has 7113** registered for an unlock-notify callback on the conclusion of connection 7114** C's transaction, where connection C is waiting on connection A. ^Any 7115** number of levels of indirection are allowed. 7116** 7117** <b>The "DROP TABLE" Exception</b> 7118** 7119** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7120** always appropriate to call sqlite3_unlock_notify(). There is however, 7121** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7122** SQLite checks if there are any currently executing SELECT statements 7123** that belong to the same connection. If there are, SQLITE_LOCKED is 7124** returned. In this case there is no "blocking connection", so invoking 7125** sqlite3_unlock_notify() results in the unlock-notify callback being 7126** invoked immediately. If the application then re-attempts the "DROP TABLE" 7127** or "DROP INDEX" query, an infinite loop might be the result. 7128** 7129** One way around this problem is to check the extended error code returned 7130** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7131** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7132** the special "DROP TABLE/INDEX" case, the extended error code is just 7133** SQLITE_LOCKED.)^ 7134*/ 7135int sqlite3_unlock_notify( 7136 sqlite3 *pBlocked, /* Waiting connection */ 7137 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7138 void *pNotifyArg /* Argument to pass to xNotify */ 7139); 7140 7141 7142/* 7143** CAPI3REF: String Comparison 7144** 7145** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7146** and extensions to compare the contents of two buffers containing UTF-8 7147** strings in a case-independent fashion, using the same definition of "case 7148** independence" that SQLite uses internally when comparing identifiers. 7149*/ 7150int sqlite3_stricmp(const char *, const char *); 7151int sqlite3_strnicmp(const char *, const char *, int); 7152 7153/* 7154** CAPI3REF: String Globbing 7155* 7156** ^The [sqlite3_strglob(P,X)] interface returns zero if string X matches 7157** the glob pattern P, and it returns non-zero if string X does not match 7158** the glob pattern P. ^The definition of glob pattern matching used in 7159** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7160** SQL dialect used by SQLite. ^The sqlite3_strglob(P,X) function is case 7161** sensitive. 7162** 7163** Note that this routine returns zero on a match and non-zero if the strings 7164** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7165*/ 7166int sqlite3_strglob(const char *zGlob, const char *zStr); 7167 7168/* 7169** CAPI3REF: Error Logging Interface 7170** 7171** ^The [sqlite3_log()] interface writes a message into the [error log] 7172** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7173** ^If logging is enabled, the zFormat string and subsequent arguments are 7174** used with [sqlite3_snprintf()] to generate the final output string. 7175** 7176** The sqlite3_log() interface is intended for use by extensions such as 7177** virtual tables, collating functions, and SQL functions. While there is 7178** nothing to prevent an application from calling sqlite3_log(), doing so 7179** is considered bad form. 7180** 7181** The zFormat string must not be NULL. 7182** 7183** To avoid deadlocks and other threading problems, the sqlite3_log() routine 7184** will not use dynamically allocated memory. The log message is stored in 7185** a fixed-length buffer on the stack. If the log message is longer than 7186** a few hundred characters, it will be truncated to the length of the 7187** buffer. 7188*/ 7189void sqlite3_log(int iErrCode, const char *zFormat, ...); 7190 7191/* 7192** CAPI3REF: Write-Ahead Log Commit Hook 7193** 7194** ^The [sqlite3_wal_hook()] function is used to register a callback that 7195** is invoked each time data is committed to a database in wal mode. 7196** 7197** ^(The callback is invoked by SQLite after the commit has taken place and 7198** the associated write-lock on the database released)^, so the implementation 7199** may read, write or [checkpoint] the database as required. 7200** 7201** ^The first parameter passed to the callback function when it is invoked 7202** is a copy of the third parameter passed to sqlite3_wal_hook() when 7203** registering the callback. ^The second is a copy of the database handle. 7204** ^The third parameter is the name of the database that was written to - 7205** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 7206** is the number of pages currently in the write-ahead log file, 7207** including those that were just committed. 7208** 7209** The callback function should normally return [SQLITE_OK]. ^If an error 7210** code is returned, that error will propagate back up through the 7211** SQLite code base to cause the statement that provoked the callback 7212** to report an error, though the commit will have still occurred. If the 7213** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 7214** that does not correspond to any valid SQLite error code, the results 7215** are undefined. 7216** 7217** A single database handle may have at most a single write-ahead log callback 7218** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 7219** previously registered write-ahead log callback. ^Note that the 7220** [sqlite3_wal_autocheckpoint()] interface and the 7221** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 7222** those overwrite any prior [sqlite3_wal_hook()] settings. 7223*/ 7224void *sqlite3_wal_hook( 7225 sqlite3*, 7226 int(*)(void *,sqlite3*,const char*,int), 7227 void* 7228); 7229 7230/* 7231** CAPI3REF: Configure an auto-checkpoint 7232** 7233** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 7234** [sqlite3_wal_hook()] that causes any database on [database connection] D 7235** to automatically [checkpoint] 7236** after committing a transaction if there are N or 7237** more frames in the [write-ahead log] file. ^Passing zero or 7238** a negative value as the nFrame parameter disables automatic 7239** checkpoints entirely. 7240** 7241** ^The callback registered by this function replaces any existing callback 7242** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 7243** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 7244** configured by this function. 7245** 7246** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 7247** from SQL. 7248** 7249** ^Checkpoints initiated by this mechanism are 7250** [sqlite3_wal_checkpoint_v2|PASSIVE]. 7251** 7252** ^Every new [database connection] defaults to having the auto-checkpoint 7253** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 7254** pages. The use of this interface 7255** is only necessary if the default setting is found to be suboptimal 7256** for a particular application. 7257*/ 7258int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 7259 7260/* 7261** CAPI3REF: Checkpoint a database 7262** 7263** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 7264** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 7265** 7266** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 7267** [write-ahead log] for database X on [database connection] D to be 7268** transferred into the database file and for the write-ahead log to 7269** be reset. See the [checkpointing] documentation for addition 7270** information. 7271** 7272** This interface used to be the only way to cause a checkpoint to 7273** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 7274** interface was added. This interface is retained for backwards 7275** compatibility and as a convenience for applications that need to manually 7276** start a callback but which do not need the full power (and corresponding 7277** complication) of [sqlite3_wal_checkpoint_v2()]. 7278*/ 7279int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 7280 7281/* 7282** CAPI3REF: Checkpoint a database 7283** 7284** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 7285** operation on database X of [database connection] D in mode M. Status 7286** information is written back into integers pointed to by L and C.)^ 7287** ^(The M parameter must be a valid [checkpoint mode]:)^ 7288** 7289** <dl> 7290** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 7291** ^Checkpoint as many frames as possible without waiting for any database 7292** readers or writers to finish, then sync the database file if all frames 7293** in the log were checkpointed. ^The [busy-handler callback] 7294** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 7295** ^On the other hand, passive mode might leave the checkpoint unfinished 7296** if there are concurrent readers or writers. 7297** 7298** <dt>SQLITE_CHECKPOINT_FULL<dd> 7299** ^This mode blocks (it invokes the 7300** [sqlite3_busy_handler|busy-handler callback]) until there is no 7301** database writer and all readers are reading from the most recent database 7302** snapshot. ^It then checkpoints all frames in the log file and syncs the 7303** database file. ^This mode blocks new database writers while it is pending, 7304** but new database readers are allowed to continue unimpeded. 7305** 7306** <dt>SQLITE_CHECKPOINT_RESTART<dd> 7307** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 7308** that after checkpointing the log file it blocks (calls the 7309** [busy-handler callback]) 7310** until all readers are reading from the database file only. ^This ensures 7311** that the next writer will restart the log file from the beginning. 7312** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 7313** database writer attempts while it is pending, but does not impede readers. 7314** 7315** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 7316** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 7317** addition that it also truncates the log file to zero bytes just prior 7318** to a successful return. 7319** </dl> 7320** 7321** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 7322** the log file or to -1 if the checkpoint could not run because 7323** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 7324** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 7325** log file (including any that were already checkpointed before the function 7326** was called) or to -1 if the checkpoint could not run due to an error or 7327** because the database is not in WAL mode. ^Note that upon successful 7328** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 7329** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 7330** 7331** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 7332** any other process is running a checkpoint operation at the same time, the 7333** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 7334** busy-handler configured, it will not be invoked in this case. 7335** 7336** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 7337** exclusive "writer" lock on the database file. ^If the writer lock cannot be 7338** obtained immediately, and a busy-handler is configured, it is invoked and 7339** the writer lock retried until either the busy-handler returns 0 or the lock 7340** is successfully obtained. ^The busy-handler is also invoked while waiting for 7341** database readers as described above. ^If the busy-handler returns 0 before 7342** the writer lock is obtained or while waiting for database readers, the 7343** checkpoint operation proceeds from that point in the same way as 7344** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 7345** without blocking any further. ^SQLITE_BUSY is returned in this case. 7346** 7347** ^If parameter zDb is NULL or points to a zero length string, then the 7348** specified operation is attempted on all WAL databases [attached] to 7349** [database connection] db. In this case the 7350** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 7351** an SQLITE_BUSY error is encountered when processing one or more of the 7352** attached WAL databases, the operation is still attempted on any remaining 7353** attached databases and SQLITE_BUSY is returned at the end. ^If any other 7354** error occurs while processing an attached database, processing is abandoned 7355** and the error code is returned to the caller immediately. ^If no error 7356** (SQLITE_BUSY or otherwise) is encountered while processing the attached 7357** databases, SQLITE_OK is returned. 7358** 7359** ^If database zDb is the name of an attached database that is not in WAL 7360** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 7361** zDb is not NULL (or a zero length string) and is not the name of any 7362** attached database, SQLITE_ERROR is returned to the caller. 7363** 7364** ^Unless it returns SQLITE_MISUSE, 7365** the sqlite3_wal_checkpoint_v2() interface 7366** sets the error information that is queried by 7367** [sqlite3_errcode()] and [sqlite3_errmsg()]. 7368** 7369** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 7370** from SQL. 7371*/ 7372int sqlite3_wal_checkpoint_v2( 7373 sqlite3 *db, /* Database handle */ 7374 const char *zDb, /* Name of attached database (or NULL) */ 7375 int eMode, /* SQLITE_CHECKPOINT_* value */ 7376 int *pnLog, /* OUT: Size of WAL log in frames */ 7377 int *pnCkpt /* OUT: Total number of frames checkpointed */ 7378); 7379 7380/* 7381** CAPI3REF: Checkpoint Mode Values 7382** KEYWORDS: {checkpoint mode} 7383** 7384** These constants define all valid values for the "checkpoint mode" passed 7385** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 7386** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 7387** meaning of each of these checkpoint modes. 7388*/ 7389#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 7390#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 7391#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 7392#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 7393 7394/* 7395** CAPI3REF: Virtual Table Interface Configuration 7396** 7397** This function may be called by either the [xConnect] or [xCreate] method 7398** of a [virtual table] implementation to configure 7399** various facets of the virtual table interface. 7400** 7401** If this interface is invoked outside the context of an xConnect or 7402** xCreate virtual table method then the behavior is undefined. 7403** 7404** At present, there is only one option that may be configured using 7405** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 7406** may be added in the future. 7407*/ 7408int sqlite3_vtab_config(sqlite3*, int op, ...); 7409 7410/* 7411** CAPI3REF: Virtual Table Configuration Options 7412** 7413** These macros define the various options to the 7414** [sqlite3_vtab_config()] interface that [virtual table] implementations 7415** can use to customize and optimize their behavior. 7416** 7417** <dl> 7418** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 7419** <dd>Calls of the form 7420** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 7421** where X is an integer. If X is zero, then the [virtual table] whose 7422** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 7423** support constraints. In this configuration (which is the default) if 7424** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 7425** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 7426** specified as part of the users SQL statement, regardless of the actual 7427** ON CONFLICT mode specified. 7428** 7429** If X is non-zero, then the virtual table implementation guarantees 7430** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 7431** any modifications to internal or persistent data structures have been made. 7432** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 7433** is able to roll back a statement or database transaction, and abandon 7434** or continue processing the current SQL statement as appropriate. 7435** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 7436** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 7437** had been ABORT. 7438** 7439** Virtual table implementations that are required to handle OR REPLACE 7440** must do so within the [xUpdate] method. If a call to the 7441** [sqlite3_vtab_on_conflict()] function indicates that the current ON 7442** CONFLICT policy is REPLACE, the virtual table implementation should 7443** silently replace the appropriate rows within the xUpdate callback and 7444** return SQLITE_OK. Or, if this is not possible, it may return 7445** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 7446** constraint handling. 7447** </dl> 7448*/ 7449#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 7450 7451/* 7452** CAPI3REF: Determine The Virtual Table Conflict Policy 7453** 7454** This function may only be called from within a call to the [xUpdate] method 7455** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 7456** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 7457** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 7458** of the SQL statement that triggered the call to the [xUpdate] method of the 7459** [virtual table]. 7460*/ 7461int sqlite3_vtab_on_conflict(sqlite3 *); 7462 7463/* 7464** CAPI3REF: Conflict resolution modes 7465** KEYWORDS: {conflict resolution mode} 7466** 7467** These constants are returned by [sqlite3_vtab_on_conflict()] to 7468** inform a [virtual table] implementation what the [ON CONFLICT] mode 7469** is for the SQL statement being evaluated. 7470** 7471** Note that the [SQLITE_IGNORE] constant is also used as a potential 7472** return value from the [sqlite3_set_authorizer()] callback and that 7473** [SQLITE_ABORT] is also a [result code]. 7474*/ 7475#define SQLITE_ROLLBACK 1 7476/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 7477#define SQLITE_FAIL 3 7478/* #define SQLITE_ABORT 4 // Also an error code */ 7479#define SQLITE_REPLACE 5 7480 7481/* 7482** CAPI3REF: Prepared Statement Scan Status Opcodes 7483** KEYWORDS: {scanstatus options} 7484** 7485** The following constants can be used for the T parameter to the 7486** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 7487** different metric for sqlite3_stmt_scanstatus() to return. 7488** 7489** When the value returned to V is a string, space to hold that string is 7490** managed by the prepared statement S and will be automatically freed when 7491** S is finalized. 7492** 7493** <dl> 7494** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 7495** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 7496** set to the total number of times that the X-th loop has run.</dd> 7497** 7498** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 7499** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 7500** to the total number of rows examined by all iterations of the X-th loop.</dd> 7501** 7502** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 7503** <dd>^The "double" variable pointed to by the T parameter will be set to the 7504** query planner's estimate for the average number of rows output from each 7505** iteration of the X-th loop. If the query planner's estimates was accurate, 7506** then this value will approximate the quotient NVISIT/NLOOP and the 7507** product of this value for all prior loops with the same SELECTID will 7508** be the NLOOP value for the current loop. 7509** 7510** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 7511** <dd>^The "const char *" variable pointed to by the T parameter will be set 7512** to a zero-terminated UTF-8 string containing the name of the index or table 7513** used for the X-th loop. 7514** 7515** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 7516** <dd>^The "const char *" variable pointed to by the T parameter will be set 7517** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 7518** description for the X-th loop. 7519** 7520** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 7521** <dd>^The "int" variable pointed to by the T parameter will be set to the 7522** "select-id" for the X-th loop. The select-id identifies which query or 7523** subquery the loop is part of. The main query has a select-id of zero. 7524** The select-id is the same value as is output in the first column 7525** of an [EXPLAIN QUERY PLAN] query. 7526** </dl> 7527*/ 7528#define SQLITE_SCANSTAT_NLOOP 0 7529#define SQLITE_SCANSTAT_NVISIT 1 7530#define SQLITE_SCANSTAT_EST 2 7531#define SQLITE_SCANSTAT_NAME 3 7532#define SQLITE_SCANSTAT_EXPLAIN 4 7533#define SQLITE_SCANSTAT_SELECTID 5 7534 7535/* 7536** CAPI3REF: Prepared Statement Scan Status 7537** 7538** This interface returns information about the predicted and measured 7539** performance for pStmt. Advanced applications can use this 7540** interface to compare the predicted and the measured performance and 7541** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 7542** 7543** Since this interface is expected to be rarely used, it is only 7544** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 7545** compile-time option. 7546** 7547** The "iScanStatusOp" parameter determines which status information to return. 7548** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 7549** of this interface is undefined. 7550** ^The requested measurement is written into a variable pointed to by 7551** the "pOut" parameter. 7552** Parameter "idx" identifies the specific loop to retrieve statistics for. 7553** Loops are numbered starting from zero. ^If idx is out of range - less than 7554** zero or greater than or equal to the total number of loops used to implement 7555** the statement - a non-zero value is returned and the variable that pOut 7556** points to is unchanged. 7557** 7558** ^Statistics might not be available for all loops in all statements. ^In cases 7559** where there exist loops with no available statistics, this function behaves 7560** as if the loop did not exist - it returns non-zero and leave the variable 7561** that pOut points to unchanged. 7562** 7563** See also: [sqlite3_stmt_scanstatus_reset()] 7564*/ 7565SQLITE_EXPERIMENTAL int sqlite3_stmt_scanstatus( 7566 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 7567 int idx, /* Index of loop to report on */ 7568 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 7569 void *pOut /* Result written here */ 7570); 7571 7572/* 7573** CAPI3REF: Zero Scan-Status Counters 7574** 7575** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 7576** 7577** This API is only available if the library is built with pre-processor 7578** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 7579*/ 7580SQLITE_EXPERIMENTAL void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 7581 7582 7583/* 7584** Undo the hack that converts floating point types to integer for 7585** builds on processors without floating point support. 7586*/ 7587#ifdef SQLITE_OMIT_FLOATING_POINT 7588# undef double 7589#endif 7590 7591#ifdef __cplusplus 7592} /* End of the 'extern "C"' block */ 7593#endif 7594#endif /* _SQLITE3_H_ */ 7595