sqlite3.h revision 9d9edcf91e6d39f940ba1740956a12c0aef52334
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#ifndef SQLITE_API 53# define SQLITE_API 54#endif 55 56 57/* 58** These no-op macros are used in front of interfaces to mark those 59** interfaces as either deprecated or experimental. New applications 60** should not use deprecated interfaces - they are support for backwards 61** compatibility only. Application writers should be aware that 62** experimental interfaces are subject to change in point releases. 63** 64** These macros used to resolve to various kinds of compiler magic that 65** would generate warning messages when they were used. But that 66** compiler magic ended up generating such a flurry of bug reports 67** that we have taken it all out and gone back to using simple 68** noop macros. 69*/ 70#define SQLITE_DEPRECATED 71#define SQLITE_EXPERIMENTAL 72 73/* 74** Ensure these symbols were not defined by some previous header file. 75*/ 76#ifdef SQLITE_VERSION 77# undef SQLITE_VERSION 78#endif 79#ifdef SQLITE_VERSION_NUMBER 80# undef SQLITE_VERSION_NUMBER 81#endif 82 83/* 84** CAPI3REF: Compile-Time Library Version Numbers 85** 86** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 87** evaluates to a string literal that is the SQLite version in the 88** format "X.Y.Z" where X is the major version number (always 3 for 89** SQLite3) and Y is the minor version number and Z is the release number.)^ 90** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 91** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 92** numbers used in [SQLITE_VERSION].)^ 93** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 94** be larger than the release from which it is derived. Either Y will 95** be held constant and Z will be incremented or else Y will be incremented 96** and Z will be reset to zero. 97** 98** Since version 3.6.18, SQLite source code has been stored in the 99** <a href="http://www.fossil-scm.org/">Fossil configuration management 100** system</a>. ^The SQLITE_SOURCE_ID macro evalutes to 101** a string which identifies a particular check-in of SQLite 102** within its configuration management system. ^The SQLITE_SOURCE_ID 103** string contains the date and time of the check-in (UTC) and an SHA1 104** hash of the entire source tree. 105** 106** See also: [sqlite3_libversion()], 107** [sqlite3_libversion_number()], [sqlite3_sourceid()], 108** [sqlite_version()] and [sqlite_source_id()]. 109*/ 110#define SQLITE_VERSION "3.6.22" 111#define SQLITE_VERSION_NUMBER 3006022 112#define SQLITE_SOURCE_ID "2010-01-05 15:30:36 28d0d7710761114a44a1a3a425a6883c661f06e7" 113 114/* 115** CAPI3REF: Run-Time Library Version Numbers 116** KEYWORDS: sqlite3_version 117** 118** These interfaces provide the same information as the [SQLITE_VERSION], 119** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 120** but are associated with the library instead of the header file. ^(Cautious 121** programmers might include assert() statements in their application to 122** verify that values returned by these interfaces match the macros in 123** the header, and thus insure that the application is 124** compiled with matching library and header files. 125** 126** <blockquote><pre> 127** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 128** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 129** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 130** </pre></blockquote>)^ 131** 132** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 133** macro. ^The sqlite3_libversion() function returns a pointer to the 134** to the sqlite3_version[] string constant. The sqlite3_libversion() 135** function is provided for use in DLLs since DLL users usually do not have 136** direct access to string constants within the DLL. ^The 137** sqlite3_libversion_number() function returns an integer equal to 138** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function a pointer 139** to a string constant whose value is the same as the [SQLITE_SOURCE_ID] 140** C preprocessor macro. 141** 142** See also: [sqlite_version()] and [sqlite_source_id()]. 143*/ 144SQLITE_API SQLITE_EXTERN const char sqlite3_version[]; 145SQLITE_API const char *sqlite3_libversion(void); 146SQLITE_API const char *sqlite3_sourceid(void); 147SQLITE_API int sqlite3_libversion_number(void); 148 149/* 150** CAPI3REF: Test To See If The Library Is Threadsafe 151** 152** ^The sqlite3_threadsafe() function returns zero if and only if 153** SQLite was compiled mutexing code omitted due to the 154** [SQLITE_THREADSAFE] compile-time option being set to 0. 155** 156** SQLite can be compiled with or without mutexes. When 157** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 158** are enabled and SQLite is threadsafe. When the 159** [SQLITE_THREADSAFE] macro is 0, 160** the mutexes are omitted. Without the mutexes, it is not safe 161** to use SQLite concurrently from more than one thread. 162** 163** Enabling mutexes incurs a measurable performance penalty. 164** So if speed is of utmost importance, it makes sense to disable 165** the mutexes. But for maximum safety, mutexes should be enabled. 166** ^The default behavior is for mutexes to be enabled. 167** 168** This interface can be used by an application to make sure that the 169** version of SQLite that it is linking against was compiled with 170** the desired setting of the [SQLITE_THREADSAFE] macro. 171** 172** This interface only reports on the compile-time mutex setting 173** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 174** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 175** can be fully or partially disabled using a call to [sqlite3_config()] 176** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 177** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the 178** sqlite3_threadsafe() function shows only the compile-time setting of 179** thread safety, not any run-time changes to that setting made by 180** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 181** is unchanged by calls to sqlite3_config().)^ 182** 183** See the [threading mode] documentation for additional information. 184*/ 185SQLITE_API int sqlite3_threadsafe(void); 186 187/* 188** CAPI3REF: Database Connection Handle 189** KEYWORDS: {database connection} {database connections} 190** 191** Each open SQLite database is represented by a pointer to an instance of 192** the opaque structure named "sqlite3". It is useful to think of an sqlite3 193** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 194** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 195** is its destructor. There are many other interfaces (such as 196** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 197** [sqlite3_busy_timeout()] to name but three) that are methods on an 198** sqlite3 object. 199*/ 200typedef struct sqlite3 sqlite3; 201 202/* 203** CAPI3REF: 64-Bit Integer Types 204** KEYWORDS: sqlite_int64 sqlite_uint64 205** 206** Because there is no cross-platform way to specify 64-bit integer types 207** SQLite includes typedefs for 64-bit signed and unsigned integers. 208** 209** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 210** The sqlite_int64 and sqlite_uint64 types are supported for backwards 211** compatibility only. 212** 213** ^The sqlite3_int64 and sqlite_int64 types can store integer values 214** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 215** sqlite3_uint64 and sqlite_uint64 types can store integer values 216** between 0 and +18446744073709551615 inclusive. 217*/ 218#ifdef SQLITE_INT64_TYPE 219 typedef SQLITE_INT64_TYPE sqlite_int64; 220 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 221#elif defined(_MSC_VER) || defined(__BORLANDC__) 222 typedef __int64 sqlite_int64; 223 typedef unsigned __int64 sqlite_uint64; 224#else 225 typedef long long int sqlite_int64; 226 typedef unsigned long long int sqlite_uint64; 227#endif 228typedef sqlite_int64 sqlite3_int64; 229typedef sqlite_uint64 sqlite3_uint64; 230 231/* 232** If compiling for a processor that lacks floating point support, 233** substitute integer for floating-point. 234*/ 235#ifdef SQLITE_OMIT_FLOATING_POINT 236# define double sqlite3_int64 237#endif 238 239/* 240** CAPI3REF: Closing A Database Connection 241** 242** ^The sqlite3_close() routine is the destructor for the [sqlite3] object. 243** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is 244** successfullly destroyed and all associated resources are deallocated. 245** 246** Applications must [sqlite3_finalize | finalize] all [prepared statements] 247** and [sqlite3_blob_close | close] all [BLOB handles] associated with 248** the [sqlite3] object prior to attempting to close the object. ^If 249** sqlite3_close() is called on a [database connection] that still has 250** outstanding [prepared statements] or [BLOB handles], then it returns 251** SQLITE_BUSY. 252** 253** ^If [sqlite3_close()] is invoked while a transaction is open, 254** the transaction is automatically rolled back. 255** 256** The C parameter to [sqlite3_close(C)] must be either a NULL 257** pointer or an [sqlite3] object pointer obtained 258** from [sqlite3_open()], [sqlite3_open16()], or 259** [sqlite3_open_v2()], and not previously closed. 260** ^Calling sqlite3_close() with a NULL pointer argument is a 261** harmless no-op. 262*/ 263SQLITE_API int sqlite3_close(sqlite3 *); 264 265/* 266** The type for a callback function. 267** This is legacy and deprecated. It is included for historical 268** compatibility and is not documented. 269*/ 270typedef int (*sqlite3_callback)(void*,int,char**, char**); 271 272/* 273** CAPI3REF: One-Step Query Execution Interface 274** 275** The sqlite3_exec() interface is a convenience wrapper around 276** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 277** that allows an application to run multiple statements of SQL 278** without having to use a lot of C code. 279** 280** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 281** semicolon-separate SQL statements passed into its 2nd argument, 282** in the context of the [database connection] passed in as its 1st 283** argument. ^If the callback function of the 3rd argument to 284** sqlite3_exec() is not NULL, then it is invoked for each result row 285** coming out of the evaluated SQL statements. ^The 4th argument to 286** to sqlite3_exec() is relayed through to the 1st argument of each 287** callback invocation. ^If the callback pointer to sqlite3_exec() 288** is NULL, then no callback is ever invoked and result rows are 289** ignored. 290** 291** ^If an error occurs while evaluating the SQL statements passed into 292** sqlite3_exec(), then execution of the current statement stops and 293** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 294** is not NULL then any error message is written into memory obtained 295** from [sqlite3_malloc()] and passed back through the 5th parameter. 296** To avoid memory leaks, the application should invoke [sqlite3_free()] 297** on error message strings returned through the 5th parameter of 298** of sqlite3_exec() after the error message string is no longer needed. 299** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 300** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 301** NULL before returning. 302** 303** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 304** routine returns SQLITE_ABORT without invoking the callback again and 305** without running any subsequent SQL statements. 306** 307** ^The 2nd argument to the sqlite3_exec() callback function is the 308** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 309** callback is an array of pointers to strings obtained as if from 310** [sqlite3_column_text()], one for each column. ^If an element of a 311** result row is NULL then the corresponding string pointer for the 312** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 313** sqlite3_exec() callback is an array of pointers to strings where each 314** entry represents the name of corresponding result column as obtained 315** from [sqlite3_column_name()]. 316** 317** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 318** to an empty string, or a pointer that contains only whitespace and/or 319** SQL comments, then no SQL statements are evaluated and the database 320** is not changed. 321** 322** Restrictions: 323** 324** <ul> 325** <li> The application must insure that the 1st parameter to sqlite3_exec() 326** is a valid and open [database connection]. 327** <li> The application must not close [database connection] specified by 328** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 329** <li> The application must not modify the SQL statement text passed into 330** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 331** </ul> 332*/ 333SQLITE_API int sqlite3_exec( 334 sqlite3*, /* An open database */ 335 const char *sql, /* SQL to be evaluated */ 336 int (*callback)(void*,int,char**,char**), /* Callback function */ 337 void *, /* 1st argument to callback */ 338 char **errmsg /* Error msg written here */ 339); 340 341/* 342** CAPI3REF: Result Codes 343** KEYWORDS: SQLITE_OK {error code} {error codes} 344** KEYWORDS: {result code} {result codes} 345** 346** Many SQLite functions return an integer result code from the set shown 347** here in order to indicates success or failure. 348** 349** New error codes may be added in future versions of SQLite. 350** 351** See also: [SQLITE_IOERR_READ | extended result codes] 352*/ 353#define SQLITE_OK 0 /* Successful result */ 354/* beginning-of-error-codes */ 355#define SQLITE_ERROR 1 /* SQL error or missing database */ 356#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 357#define SQLITE_PERM 3 /* Access permission denied */ 358#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 359#define SQLITE_BUSY 5 /* The database file is locked */ 360#define SQLITE_LOCKED 6 /* A table in the database is locked */ 361#define SQLITE_NOMEM 7 /* A malloc() failed */ 362#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 363#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 364#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 365#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 366#define SQLITE_NOTFOUND 12 /* NOT USED. Table or record not found */ 367#define SQLITE_FULL 13 /* Insertion failed because database is full */ 368#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 369#define SQLITE_PROTOCOL 15 /* NOT USED. Database lock protocol error */ 370#define SQLITE_EMPTY 16 /* Database is empty */ 371#define SQLITE_SCHEMA 17 /* The database schema changed */ 372#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 373#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 374#define SQLITE_MISMATCH 20 /* Data type mismatch */ 375#define SQLITE_MISUSE 21 /* Library used incorrectly */ 376#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 377#define SQLITE_AUTH 23 /* Authorization denied */ 378#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 379#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 380#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 381#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 382#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 383/* end-of-error-codes */ 384 385/* 386** CAPI3REF: Extended Result Codes 387** KEYWORDS: {extended error code} {extended error codes} 388** KEYWORDS: {extended result code} {extended result codes} 389** 390** In its default configuration, SQLite API routines return one of 26 integer 391** [SQLITE_OK | result codes]. However, experience has shown that many of 392** these result codes are too coarse-grained. They do not provide as 393** much information about problems as programmers might like. In an effort to 394** address this, newer versions of SQLite (version 3.3.8 and later) include 395** support for additional result codes that provide more detailed information 396** about errors. The extended result codes are enabled or disabled 397** on a per database connection basis using the 398** [sqlite3_extended_result_codes()] API. 399** 400** Some of the available extended result codes are listed here. 401** One may expect the number of extended result codes will be expand 402** over time. Software that uses extended result codes should expect 403** to see new result codes in future releases of SQLite. 404** 405** The SQLITE_OK result code will never be extended. It will always 406** be exactly zero. 407*/ 408#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 409#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 410#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 411#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 412#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 413#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 414#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 415#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 416#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 417#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 418#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 419#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 420#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 421#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 422#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 423#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 424#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 425#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8) ) 426 427/* 428** CAPI3REF: Flags For File Open Operations 429** 430** These bit values are intended for use in the 431** 3rd parameter to the [sqlite3_open_v2()] interface and 432** in the 4th parameter to the xOpen method of the 433** [sqlite3_vfs] object. 434*/ 435#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 436#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 437#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 438#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 439#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 440#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 441#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 442#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 443#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 444#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 445#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 446#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 447#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 448#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 449#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 450#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 451 452/* 453** CAPI3REF: Device Characteristics 454** 455** The xDeviceCapabilities method of the [sqlite3_io_methods] 456** object returns an integer which is a vector of the these 457** bit values expressing I/O characteristics of the mass storage 458** device that holds the file that the [sqlite3_io_methods] 459** refers to. 460** 461** The SQLITE_IOCAP_ATOMIC property means that all writes of 462** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 463** mean that writes of blocks that are nnn bytes in size and 464** are aligned to an address which is an integer multiple of 465** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 466** that when data is appended to a file, the data is appended 467** first then the size of the file is extended, never the other 468** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 469** information is written to disk in the same order as calls 470** to xWrite(). 471*/ 472#define SQLITE_IOCAP_ATOMIC 0x00000001 473#define SQLITE_IOCAP_ATOMIC512 0x00000002 474#define SQLITE_IOCAP_ATOMIC1K 0x00000004 475#define SQLITE_IOCAP_ATOMIC2K 0x00000008 476#define SQLITE_IOCAP_ATOMIC4K 0x00000010 477#define SQLITE_IOCAP_ATOMIC8K 0x00000020 478#define SQLITE_IOCAP_ATOMIC16K 0x00000040 479#define SQLITE_IOCAP_ATOMIC32K 0x00000080 480#define SQLITE_IOCAP_ATOMIC64K 0x00000100 481#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 482#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 483 484/* 485** CAPI3REF: File Locking Levels 486** 487** SQLite uses one of these integer values as the second 488** argument to calls it makes to the xLock() and xUnlock() methods 489** of an [sqlite3_io_methods] object. 490*/ 491#define SQLITE_LOCK_NONE 0 492#define SQLITE_LOCK_SHARED 1 493#define SQLITE_LOCK_RESERVED 2 494#define SQLITE_LOCK_PENDING 3 495#define SQLITE_LOCK_EXCLUSIVE 4 496 497/* 498** CAPI3REF: Synchronization Type Flags 499** 500** When SQLite invokes the xSync() method of an 501** [sqlite3_io_methods] object it uses a combination of 502** these integer values as the second argument. 503** 504** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 505** sync operation only needs to flush data to mass storage. Inode 506** information need not be flushed. If the lower four bits of the flag 507** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 508** If the lower four bits equal SQLITE_SYNC_FULL, that means 509** to use Mac OS X style fullsync instead of fsync(). 510*/ 511#define SQLITE_SYNC_NORMAL 0x00002 512#define SQLITE_SYNC_FULL 0x00003 513#define SQLITE_SYNC_DATAONLY 0x00010 514 515/* 516** CAPI3REF: OS Interface Open File Handle 517** 518** An [sqlite3_file] object represents an open file in the 519** [sqlite3_vfs | OS interface layer]. Individual OS interface 520** implementations will 521** want to subclass this object by appending additional fields 522** for their own use. The pMethods entry is a pointer to an 523** [sqlite3_io_methods] object that defines methods for performing 524** I/O operations on the open file. 525*/ 526typedef struct sqlite3_file sqlite3_file; 527struct sqlite3_file { 528 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 529}; 530 531/* 532** CAPI3REF: OS Interface File Virtual Methods Object 533** 534** Every file opened by the [sqlite3_vfs] xOpen method populates an 535** [sqlite3_file] object (or, more commonly, a subclass of the 536** [sqlite3_file] object) with a pointer to an instance of this object. 537** This object defines the methods used to perform various operations 538** against the open file represented by the [sqlite3_file] object. 539** 540** If the xOpen method sets the sqlite3_file.pMethods element 541** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 542** may be invoked even if the xOpen reported that it failed. The 543** only way to prevent a call to xClose following a failed xOpen 544** is for the xOpen to set the sqlite3_file.pMethods element to NULL. 545** 546** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 547** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 548** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 549** flag may be ORed in to indicate that only the data of the file 550** and not its inode needs to be synced. 551** 552** The integer values to xLock() and xUnlock() are one of 553** <ul> 554** <li> [SQLITE_LOCK_NONE], 555** <li> [SQLITE_LOCK_SHARED], 556** <li> [SQLITE_LOCK_RESERVED], 557** <li> [SQLITE_LOCK_PENDING], or 558** <li> [SQLITE_LOCK_EXCLUSIVE]. 559** </ul> 560** xLock() increases the lock. xUnlock() decreases the lock. 561** The xCheckReservedLock() method checks whether any database connection, 562** either in this process or in some other process, is holding a RESERVED, 563** PENDING, or EXCLUSIVE lock on the file. It returns true 564** if such a lock exists and false otherwise. 565** 566** The xFileControl() method is a generic interface that allows custom 567** VFS implementations to directly control an open file using the 568** [sqlite3_file_control()] interface. The second "op" argument is an 569** integer opcode. The third argument is a generic pointer intended to 570** point to a structure that may contain arguments or space in which to 571** write return values. Potential uses for xFileControl() might be 572** functions to enable blocking locks with timeouts, to change the 573** locking strategy (for example to use dot-file locks), to inquire 574** about the status of a lock, or to break stale locks. The SQLite 575** core reserves all opcodes less than 100 for its own use. 576** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 577** Applications that define a custom xFileControl method should use opcodes 578** greater than 100 to avoid conflicts. 579** 580** The xSectorSize() method returns the sector size of the 581** device that underlies the file. The sector size is the 582** minimum write that can be performed without disturbing 583** other bytes in the file. The xDeviceCharacteristics() 584** method returns a bit vector describing behaviors of the 585** underlying device: 586** 587** <ul> 588** <li> [SQLITE_IOCAP_ATOMIC] 589** <li> [SQLITE_IOCAP_ATOMIC512] 590** <li> [SQLITE_IOCAP_ATOMIC1K] 591** <li> [SQLITE_IOCAP_ATOMIC2K] 592** <li> [SQLITE_IOCAP_ATOMIC4K] 593** <li> [SQLITE_IOCAP_ATOMIC8K] 594** <li> [SQLITE_IOCAP_ATOMIC16K] 595** <li> [SQLITE_IOCAP_ATOMIC32K] 596** <li> [SQLITE_IOCAP_ATOMIC64K] 597** <li> [SQLITE_IOCAP_SAFE_APPEND] 598** <li> [SQLITE_IOCAP_SEQUENTIAL] 599** </ul> 600** 601** The SQLITE_IOCAP_ATOMIC property means that all writes of 602** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 603** mean that writes of blocks that are nnn bytes in size and 604** are aligned to an address which is an integer multiple of 605** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 606** that when data is appended to a file, the data is appended 607** first then the size of the file is extended, never the other 608** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 609** information is written to disk in the same order as calls 610** to xWrite(). 611** 612** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 613** in the unread portions of the buffer with zeros. A VFS that 614** fails to zero-fill short reads might seem to work. However, 615** failure to zero-fill short reads will eventually lead to 616** database corruption. 617*/ 618typedef struct sqlite3_io_methods sqlite3_io_methods; 619struct sqlite3_io_methods { 620 int iVersion; 621 int (*xClose)(sqlite3_file*); 622 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 623 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 624 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 625 int (*xSync)(sqlite3_file*, int flags); 626 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 627 int (*xLock)(sqlite3_file*, int); 628 int (*xUnlock)(sqlite3_file*, int); 629 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 630 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 631 int (*xSectorSize)(sqlite3_file*); 632 int (*xDeviceCharacteristics)(sqlite3_file*); 633 /* Additional methods may be added in future releases */ 634}; 635 636/* 637** CAPI3REF: Standard File Control Opcodes 638** 639** These integer constants are opcodes for the xFileControl method 640** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 641** interface. 642** 643** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 644** opcode causes the xFileControl method to write the current state of 645** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 646** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 647** into an integer that the pArg argument points to. This capability 648** is used during testing and only needs to be supported when SQLITE_TEST 649** is defined. 650*/ 651#define SQLITE_FCNTL_LOCKSTATE 1 652#define SQLITE_GET_LOCKPROXYFILE 2 653#define SQLITE_SET_LOCKPROXYFILE 3 654#define SQLITE_LAST_ERRNO 4 655 656/* 657** CAPI3REF: Mutex Handle 658** 659** The mutex module within SQLite defines [sqlite3_mutex] to be an 660** abstract type for a mutex object. The SQLite core never looks 661** at the internal representation of an [sqlite3_mutex]. It only 662** deals with pointers to the [sqlite3_mutex] object. 663** 664** Mutexes are created using [sqlite3_mutex_alloc()]. 665*/ 666typedef struct sqlite3_mutex sqlite3_mutex; 667 668/* 669** CAPI3REF: OS Interface Object 670** 671** An instance of the sqlite3_vfs object defines the interface between 672** the SQLite core and the underlying operating system. The "vfs" 673** in the name of the object stands for "virtual file system". 674** 675** The value of the iVersion field is initially 1 but may be larger in 676** future versions of SQLite. Additional fields may be appended to this 677** object when the iVersion value is increased. Note that the structure 678** of the sqlite3_vfs object changes in the transaction between 679** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 680** modified. 681** 682** The szOsFile field is the size of the subclassed [sqlite3_file] 683** structure used by this VFS. mxPathname is the maximum length of 684** a pathname in this VFS. 685** 686** Registered sqlite3_vfs objects are kept on a linked list formed by 687** the pNext pointer. The [sqlite3_vfs_register()] 688** and [sqlite3_vfs_unregister()] interfaces manage this list 689** in a thread-safe way. The [sqlite3_vfs_find()] interface 690** searches the list. Neither the application code nor the VFS 691** implementation should use the pNext pointer. 692** 693** The pNext field is the only field in the sqlite3_vfs 694** structure that SQLite will ever modify. SQLite will only access 695** or modify this field while holding a particular static mutex. 696** The application should never modify anything within the sqlite3_vfs 697** object once the object has been registered. 698** 699** The zName field holds the name of the VFS module. The name must 700** be unique across all VFS modules. 701** 702** SQLite will guarantee that the zFilename parameter to xOpen 703** is either a NULL pointer or string obtained 704** from xFullPathname(). SQLite further guarantees that 705** the string will be valid and unchanged until xClose() is 706** called. Because of the previous sentence, 707** the [sqlite3_file] can safely store a pointer to the 708** filename if it needs to remember the filename for some reason. 709** If the zFilename parameter is xOpen is a NULL pointer then xOpen 710** must invent its own temporary name for the file. Whenever the 711** xFilename parameter is NULL it will also be the case that the 712** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 713** 714** The flags argument to xOpen() includes all bits set in 715** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 716** or [sqlite3_open16()] is used, then flags includes at least 717** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 718** If xOpen() opens a file read-only then it sets *pOutFlags to 719** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 720** 721** SQLite will also add one of the following flags to the xOpen() 722** call, depending on the object being opened: 723** 724** <ul> 725** <li> [SQLITE_OPEN_MAIN_DB] 726** <li> [SQLITE_OPEN_MAIN_JOURNAL] 727** <li> [SQLITE_OPEN_TEMP_DB] 728** <li> [SQLITE_OPEN_TEMP_JOURNAL] 729** <li> [SQLITE_OPEN_TRANSIENT_DB] 730** <li> [SQLITE_OPEN_SUBJOURNAL] 731** <li> [SQLITE_OPEN_MASTER_JOURNAL] 732** </ul> 733** 734** The file I/O implementation can use the object type flags to 735** change the way it deals with files. For example, an application 736** that does not care about crash recovery or rollback might make 737** the open of a journal file a no-op. Writes to this journal would 738** also be no-ops, and any attempt to read the journal would return 739** SQLITE_IOERR. Or the implementation might recognize that a database 740** file will be doing page-aligned sector reads and writes in a random 741** order and set up its I/O subsystem accordingly. 742** 743** SQLite might also add one of the following flags to the xOpen method: 744** 745** <ul> 746** <li> [SQLITE_OPEN_DELETEONCLOSE] 747** <li> [SQLITE_OPEN_EXCLUSIVE] 748** </ul> 749** 750** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 751** deleted when it is closed. The [SQLITE_OPEN_DELETEONCLOSE] 752** will be set for TEMP databases, journals and for subjournals. 753** 754** The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 755** with the [SQLITE_OPEN_CREATE] flag, which are both directly 756** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 757** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 758** SQLITE_OPEN_CREATE, is used to indicate that file should always 759** be created, and that it is an error if it already exists. 760** It is <i>not</i> used to indicate the file should be opened 761** for exclusive access. 762** 763** At least szOsFile bytes of memory are allocated by SQLite 764** to hold the [sqlite3_file] structure passed as the third 765** argument to xOpen. The xOpen method does not have to 766** allocate the structure; it should just fill it in. Note that 767** the xOpen method must set the sqlite3_file.pMethods to either 768** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 769** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 770** element will be valid after xOpen returns regardless of the success 771** or failure of the xOpen call. 772** 773** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 774** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 775** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 776** to test whether a file is at least readable. The file can be a 777** directory. 778** 779** SQLite will always allocate at least mxPathname+1 bytes for the 780** output buffer xFullPathname. The exact size of the output buffer 781** is also passed as a parameter to both methods. If the output buffer 782** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 783** handled as a fatal error by SQLite, vfs implementations should endeavor 784** to prevent this by setting mxPathname to a sufficiently large value. 785** 786** The xRandomness(), xSleep(), and xCurrentTime() interfaces 787** are not strictly a part of the filesystem, but they are 788** included in the VFS structure for completeness. 789** The xRandomness() function attempts to return nBytes bytes 790** of good-quality randomness into zOut. The return value is 791** the actual number of bytes of randomness obtained. 792** The xSleep() method causes the calling thread to sleep for at 793** least the number of microseconds given. The xCurrentTime() 794** method returns a Julian Day Number for the current date and time. 795** 796*/ 797typedef struct sqlite3_vfs sqlite3_vfs; 798struct sqlite3_vfs { 799 int iVersion; /* Structure version number */ 800 int szOsFile; /* Size of subclassed sqlite3_file */ 801 int mxPathname; /* Maximum file pathname length */ 802 sqlite3_vfs *pNext; /* Next registered VFS */ 803 const char *zName; /* Name of this virtual file system */ 804 void *pAppData; /* Pointer to application-specific data */ 805 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 806 int flags, int *pOutFlags); 807 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 808 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 809 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 810 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 811 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 812 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 813 void (*xDlClose)(sqlite3_vfs*, void*); 814 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 815 int (*xSleep)(sqlite3_vfs*, int microseconds); 816 int (*xCurrentTime)(sqlite3_vfs*, double*); 817 int (*xGetLastError)(sqlite3_vfs*, int, char *); 818 /* New fields may be appended in figure versions. The iVersion 819 ** value will increment whenever this happens. */ 820}; 821 822/* 823** CAPI3REF: Flags for the xAccess VFS method 824** 825** These integer constants can be used as the third parameter to 826** the xAccess method of an [sqlite3_vfs] object. They determine 827** what kind of permissions the xAccess method is looking for. 828** With SQLITE_ACCESS_EXISTS, the xAccess method 829** simply checks whether the file exists. 830** With SQLITE_ACCESS_READWRITE, the xAccess method 831** checks whether the file is both readable and writable. 832** With SQLITE_ACCESS_READ, the xAccess method 833** checks whether the file is readable. 834*/ 835#define SQLITE_ACCESS_EXISTS 0 836#define SQLITE_ACCESS_READWRITE 1 837#define SQLITE_ACCESS_READ 2 838 839/* 840** CAPI3REF: Initialize The SQLite Library 841** 842** ^The sqlite3_initialize() routine initializes the 843** SQLite library. ^The sqlite3_shutdown() routine 844** deallocates any resources that were allocated by sqlite3_initialize(). 845** These routines are designed to aid in process initialization and 846** shutdown on embedded systems. Workstation applications using 847** SQLite normally do not need to invoke either of these routines. 848** 849** A call to sqlite3_initialize() is an "effective" call if it is 850** the first time sqlite3_initialize() is invoked during the lifetime of 851** the process, or if it is the first time sqlite3_initialize() is invoked 852** following a call to sqlite3_shutdown(). ^(Only an effective call 853** of sqlite3_initialize() does any initialization. All other calls 854** are harmless no-ops.)^ 855** 856** A call to sqlite3_shutdown() is an "effective" call if it is the first 857** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 858** an effective call to sqlite3_shutdown() does any deinitialization. 859** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 860** 861** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 862** is not. The sqlite3_shutdown() interface must only be called from a 863** single thread. All open [database connections] must be closed and all 864** other SQLite resources must be deallocated prior to invoking 865** sqlite3_shutdown(). 866** 867** Among other things, ^sqlite3_initialize() will invoke 868** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 869** will invoke sqlite3_os_end(). 870** 871** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 872** ^If for some reason, sqlite3_initialize() is unable to initialize 873** the library (perhaps it is unable to allocate a needed resource such 874** as a mutex) it returns an [error code] other than [SQLITE_OK]. 875** 876** ^The sqlite3_initialize() routine is called internally by many other 877** SQLite interfaces so that an application usually does not need to 878** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 879** calls sqlite3_initialize() so the SQLite library will be automatically 880** initialized when [sqlite3_open()] is called if it has not be initialized 881** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 882** compile-time option, then the automatic calls to sqlite3_initialize() 883** are omitted and the application must call sqlite3_initialize() directly 884** prior to using any other SQLite interface. For maximum portability, 885** it is recommended that applications always invoke sqlite3_initialize() 886** directly prior to using any other SQLite interface. Future releases 887** of SQLite may require this. In other words, the behavior exhibited 888** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 889** default behavior in some future release of SQLite. 890** 891** The sqlite3_os_init() routine does operating-system specific 892** initialization of the SQLite library. The sqlite3_os_end() 893** routine undoes the effect of sqlite3_os_init(). Typical tasks 894** performed by these routines include allocation or deallocation 895** of static resources, initialization of global variables, 896** setting up a default [sqlite3_vfs] module, or setting up 897** a default configuration using [sqlite3_config()]. 898** 899** The application should never invoke either sqlite3_os_init() 900** or sqlite3_os_end() directly. The application should only invoke 901** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 902** interface is called automatically by sqlite3_initialize() and 903** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 904** implementations for sqlite3_os_init() and sqlite3_os_end() 905** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 906** When [custom builds | built for other platforms] 907** (using the [SQLITE_OS_OTHER=1] compile-time 908** option) the application must supply a suitable implementation for 909** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 910** implementation of sqlite3_os_init() or sqlite3_os_end() 911** must return [SQLITE_OK] on success and some other [error code] upon 912** failure. 913*/ 914SQLITE_API int sqlite3_initialize(void); 915SQLITE_API int sqlite3_shutdown(void); 916SQLITE_API int sqlite3_os_init(void); 917SQLITE_API int sqlite3_os_end(void); 918 919/* 920** CAPI3REF: Configuring The SQLite Library 921** EXPERIMENTAL 922** 923** The sqlite3_config() interface is used to make global configuration 924** changes to SQLite in order to tune SQLite to the specific needs of 925** the application. The default configuration is recommended for most 926** applications and so this routine is usually not necessary. It is 927** provided to support rare applications with unusual needs. 928** 929** The sqlite3_config() interface is not threadsafe. The application 930** must insure that no other SQLite interfaces are invoked by other 931** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 932** may only be invoked prior to library initialization using 933** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 934** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 935** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 936** Note, however, that ^sqlite3_config() can be called as part of the 937** implementation of an application-defined [sqlite3_os_init()]. 938** 939** The first argument to sqlite3_config() is an integer 940** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines 941** what property of SQLite is to be configured. Subsequent arguments 942** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option] 943** in the first argument. 944** 945** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 946** ^If the option is unknown or SQLite is unable to set the option 947** then this routine returns a non-zero [error code]. 948*/ 949SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_config(int, ...); 950 951/* 952** CAPI3REF: Configure database connections 953** EXPERIMENTAL 954** 955** The sqlite3_db_config() interface is used to make configuration 956** changes to a [database connection]. The interface is similar to 957** [sqlite3_config()] except that the changes apply to a single 958** [database connection] (specified in the first argument). The 959** sqlite3_db_config() interface should only be used immediately after 960** the database connection is created using [sqlite3_open()], 961** [sqlite3_open16()], or [sqlite3_open_v2()]. 962** 963** The second argument to sqlite3_db_config(D,V,...) is the 964** configuration verb - an integer code that indicates what 965** aspect of the [database connection] is being configured. 966** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE]. 967** New verbs are likely to be added in future releases of SQLite. 968** Additional arguments depend on the verb. 969** 970** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 971** the call is considered successful. 972*/ 973SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...); 974 975/* 976** CAPI3REF: Memory Allocation Routines 977** EXPERIMENTAL 978** 979** An instance of this object defines the interface between SQLite 980** and low-level memory allocation routines. 981** 982** This object is used in only one place in the SQLite interface. 983** A pointer to an instance of this object is the argument to 984** [sqlite3_config()] when the configuration option is 985** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 986** By creating an instance of this object 987** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 988** during configuration, an application can specify an alternative 989** memory allocation subsystem for SQLite to use for all of its 990** dynamic memory needs. 991** 992** Note that SQLite comes with several [built-in memory allocators] 993** that are perfectly adequate for the overwhelming majority of applications 994** and that this object is only useful to a tiny minority of applications 995** with specialized memory allocation requirements. This object is 996** also used during testing of SQLite in order to specify an alternative 997** memory allocator that simulates memory out-of-memory conditions in 998** order to verify that SQLite recovers gracefully from such 999** conditions. 1000** 1001** The xMalloc and xFree methods must work like the 1002** malloc() and free() functions from the standard C library. 1003** The xRealloc method must work like realloc() from the standard C library 1004** with the exception that if the second argument to xRealloc is zero, 1005** xRealloc must be a no-op - it must not perform any allocation or 1006** deallocation. ^SQLite guarantees that the second argument to 1007** xRealloc is always a value returned by a prior call to xRoundup. 1008** And so in cases where xRoundup always returns a positive number, 1009** xRealloc can perform exactly as the standard library realloc() and 1010** still be in compliance with this specification. 1011** 1012** xSize should return the allocated size of a memory allocation 1013** previously obtained from xMalloc or xRealloc. The allocated size 1014** is always at least as big as the requested size but may be larger. 1015** 1016** The xRoundup method returns what would be the allocated size of 1017** a memory allocation given a particular requested size. Most memory 1018** allocators round up memory allocations at least to the next multiple 1019** of 8. Some allocators round up to a larger multiple or to a power of 2. 1020** Every memory allocation request coming in through [sqlite3_malloc()] 1021** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1022** that causes the corresponding memory allocation to fail. 1023** 1024** The xInit method initializes the memory allocator. (For example, 1025** it might allocate any require mutexes or initialize internal data 1026** structures. The xShutdown method is invoked (indirectly) by 1027** [sqlite3_shutdown()] and should deallocate any resources acquired 1028** by xInit. The pAppData pointer is used as the only parameter to 1029** xInit and xShutdown. 1030** 1031** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1032** the xInit method, so the xInit method need not be threadsafe. The 1033** xShutdown method is only called from [sqlite3_shutdown()] so it does 1034** not need to be threadsafe either. For all other methods, SQLite 1035** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1036** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1037** it is by default) and so the methods are automatically serialized. 1038** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1039** methods must be threadsafe or else make their own arrangements for 1040** serialization. 1041** 1042** SQLite will never invoke xInit() more than once without an intervening 1043** call to xShutdown(). 1044*/ 1045typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1046struct sqlite3_mem_methods { 1047 void *(*xMalloc)(int); /* Memory allocation function */ 1048 void (*xFree)(void*); /* Free a prior allocation */ 1049 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1050 int (*xSize)(void*); /* Return the size of an allocation */ 1051 int (*xRoundup)(int); /* Round up request size to allocation size */ 1052 int (*xInit)(void*); /* Initialize the memory allocator */ 1053 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1054 void *pAppData; /* Argument to xInit() and xShutdown() */ 1055}; 1056 1057/* 1058** CAPI3REF: Configuration Options 1059** EXPERIMENTAL 1060** 1061** These constants are the available integer configuration options that 1062** can be passed as the first argument to the [sqlite3_config()] interface. 1063** 1064** New configuration options may be added in future releases of SQLite. 1065** Existing configuration options might be discontinued. Applications 1066** should check the return code from [sqlite3_config()] to make sure that 1067** the call worked. The [sqlite3_config()] interface will return a 1068** non-zero [error code] if a discontinued or unsupported configuration option 1069** is invoked. 1070** 1071** <dl> 1072** <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1073** <dd>There are no arguments to this option. ^This option sets the 1074** [threading mode] to Single-thread. In other words, it disables 1075** all mutexing and puts SQLite into a mode where it can only be used 1076** by a single thread. ^If SQLite is compiled with 1077** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1078** it is not possible to change the [threading mode] from its default 1079** value of Single-thread and so [sqlite3_config()] will return 1080** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1081** configuration option.</dd> 1082** 1083** <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1084** <dd>There are no arguments to this option. ^This option sets the 1085** [threading mode] to Multi-thread. In other words, it disables 1086** mutexing on [database connection] and [prepared statement] objects. 1087** The application is responsible for serializing access to 1088** [database connections] and [prepared statements]. But other mutexes 1089** are enabled so that SQLite will be safe to use in a multi-threaded 1090** environment as long as no two threads attempt to use the same 1091** [database connection] at the same time. ^If SQLite is compiled with 1092** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1093** it is not possible to set the Multi-thread [threading mode] and 1094** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1095** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1096** 1097** <dt>SQLITE_CONFIG_SERIALIZED</dt> 1098** <dd>There are no arguments to this option. ^This option sets the 1099** [threading mode] to Serialized. In other words, this option enables 1100** all mutexes including the recursive 1101** mutexes on [database connection] and [prepared statement] objects. 1102** In this mode (which is the default when SQLite is compiled with 1103** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1104** to [database connections] and [prepared statements] so that the 1105** application is free to use the same [database connection] or the 1106** same [prepared statement] in different threads at the same time. 1107** ^If SQLite is compiled with 1108** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1109** it is not possible to set the Serialized [threading mode] and 1110** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1111** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1112** 1113** <dt>SQLITE_CONFIG_MALLOC</dt> 1114** <dd> ^(This option takes a single argument which is a pointer to an 1115** instance of the [sqlite3_mem_methods] structure. The argument specifies 1116** alternative low-level memory allocation routines to be used in place of 1117** the memory allocation routines built into SQLite.)^ ^SQLite makes 1118** its own private copy of the content of the [sqlite3_mem_methods] structure 1119** before the [sqlite3_config()] call returns.</dd> 1120** 1121** <dt>SQLITE_CONFIG_GETMALLOC</dt> 1122** <dd> ^(This option takes a single argument which is a pointer to an 1123** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1124** structure is filled with the currently defined memory allocation routines.)^ 1125** This option can be used to overload the default memory allocation 1126** routines with a wrapper that simulations memory allocation failure or 1127** tracks memory usage, for example. </dd> 1128** 1129** <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1130** <dd> ^This option takes single argument of type int, interpreted as a 1131** boolean, which enables or disables the collection of memory allocation 1132** statistics. ^(When memory allocation statistics are disabled, the 1133** following SQLite interfaces become non-operational: 1134** <ul> 1135** <li> [sqlite3_memory_used()] 1136** <li> [sqlite3_memory_highwater()] 1137** <li> [sqlite3_soft_heap_limit()] 1138** <li> [sqlite3_status()] 1139** </ul>)^ 1140** ^Memory allocation statistics are enabled by default unless SQLite is 1141** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1142** allocation statistics are disabled by default. 1143** </dd> 1144** 1145** <dt>SQLITE_CONFIG_SCRATCH</dt> 1146** <dd> ^This option specifies a static memory buffer that SQLite can use for 1147** scratch memory. There are three arguments: A pointer an 8-byte 1148** aligned memory buffer from which the scrach allocations will be 1149** drawn, the size of each scratch allocation (sz), 1150** and the maximum number of scratch allocations (N). The sz 1151** argument must be a multiple of 16. The sz parameter should be a few bytes 1152** larger than the actual scratch space required due to internal overhead. 1153** The first argument must be a pointer to an 8-byte aligned buffer 1154** of at least sz*N bytes of memory. 1155** ^SQLite will use no more than one scratch buffer per thread. So 1156** N should be set to the expected maximum number of threads. ^SQLite will 1157** never require a scratch buffer that is more than 6 times the database 1158** page size. ^If SQLite needs needs additional scratch memory beyond 1159** what is provided by this configuration option, then 1160** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1161** 1162** <dt>SQLITE_CONFIG_PAGECACHE</dt> 1163** <dd> ^This option specifies a static memory buffer that SQLite can use for 1164** the database page cache with the default page cache implemenation. 1165** This configuration should not be used if an application-define page 1166** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option. 1167** There are three arguments to this option: A pointer to 8-byte aligned 1168** memory, the size of each page buffer (sz), and the number of pages (N). 1169** The sz argument should be the size of the largest database page 1170** (a power of two between 512 and 32768) plus a little extra for each 1171** page header. ^The page header size is 20 to 40 bytes depending on 1172** the host architecture. ^It is harmless, apart from the wasted memory, 1173** to make sz a little too large. The first 1174** argument should point to an allocation of at least sz*N bytes of memory. 1175** ^SQLite will use the memory provided by the first argument to satisfy its 1176** memory needs for the first N pages that it adds to cache. ^If additional 1177** page cache memory is needed beyond what is provided by this option, then 1178** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1179** ^The implementation might use one or more of the N buffers to hold 1180** memory accounting information. The pointer in the first argument must 1181** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1182** will be undefined.</dd> 1183** 1184** <dt>SQLITE_CONFIG_HEAP</dt> 1185** <dd> ^This option specifies a static memory buffer that SQLite will use 1186** for all of its dynamic memory allocation needs beyond those provided 1187** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1188** There are three arguments: An 8-byte aligned pointer to the memory, 1189** the number of bytes in the memory buffer, and the minimum allocation size. 1190** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1191** to using its default memory allocator (the system malloc() implementation), 1192** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1193** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1194** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1195** allocator is engaged to handle all of SQLites memory allocation needs. 1196** The first pointer (the memory pointer) must be aligned to an 8-byte 1197** boundary or subsequent behavior of SQLite will be undefined.</dd> 1198** 1199** <dt>SQLITE_CONFIG_MUTEX</dt> 1200** <dd> ^(This option takes a single argument which is a pointer to an 1201** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1202** alternative low-level mutex routines to be used in place 1203** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1204** content of the [sqlite3_mutex_methods] structure before the call to 1205** [sqlite3_config()] returns. ^If SQLite is compiled with 1206** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1207** the entire mutexing subsystem is omitted from the build and hence calls to 1208** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1209** return [SQLITE_ERROR].</dd> 1210** 1211** <dt>SQLITE_CONFIG_GETMUTEX</dt> 1212** <dd> ^(This option takes a single argument which is a pointer to an 1213** instance of the [sqlite3_mutex_methods] structure. The 1214** [sqlite3_mutex_methods] 1215** structure is filled with the currently defined mutex routines.)^ 1216** This option can be used to overload the default mutex allocation 1217** routines with a wrapper used to track mutex usage for performance 1218** profiling or testing, for example. ^If SQLite is compiled with 1219** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1220** the entire mutexing subsystem is omitted from the build and hence calls to 1221** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1222** return [SQLITE_ERROR].</dd> 1223** 1224** <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1225** <dd> ^(This option takes two arguments that determine the default 1226** memory allocation for the lookaside memory allocator on each 1227** [database connection]. The first argument is the 1228** size of each lookaside buffer slot and the second is the number of 1229** slots allocated to each database connection.)^ ^(This option sets the 1230** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1231** verb to [sqlite3_db_config()] can be used to change the lookaside 1232** configuration on individual connections.)^ </dd> 1233** 1234** <dt>SQLITE_CONFIG_PCACHE</dt> 1235** <dd> ^(This option takes a single argument which is a pointer to 1236** an [sqlite3_pcache_methods] object. This object specifies the interface 1237** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1238** object and uses it for page cache memory allocations.</dd> 1239** 1240** <dt>SQLITE_CONFIG_GETPCACHE</dt> 1241** <dd> ^(This option takes a single argument which is a pointer to an 1242** [sqlite3_pcache_methods] object. SQLite copies of the current 1243** page cache implementation into that object.)^ </dd> 1244** 1245** </dl> 1246*/ 1247#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1248#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1249#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1250#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1251#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1252#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1253#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1254#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1255#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1256#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1257#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1258/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1259#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1260#define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */ 1261#define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */ 1262 1263/* 1264** CAPI3REF: Configuration Options 1265** EXPERIMENTAL 1266** 1267** These constants are the available integer configuration options that 1268** can be passed as the second argument to the [sqlite3_db_config()] interface. 1269** 1270** New configuration options may be added in future releases of SQLite. 1271** Existing configuration options might be discontinued. Applications 1272** should check the return code from [sqlite3_db_config()] to make sure that 1273** the call worked. ^The [sqlite3_db_config()] interface will return a 1274** non-zero [error code] if a discontinued or unsupported configuration option 1275** is invoked. 1276** 1277** <dl> 1278** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1279** <dd> ^This option takes three additional arguments that determine the 1280** [lookaside memory allocator] configuration for the [database connection]. 1281** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1282** pointer to an memory buffer to use for lookaside memory. 1283** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1284** may be NULL in which case SQLite will allocate the 1285** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1286** size of each lookaside buffer slot. ^The third argument is the number of 1287** slots. The size of the buffer in the first argument must be greater than 1288** or equal to the product of the second and third arguments. The buffer 1289** must be aligned to an 8-byte boundary. ^If the second argument to 1290** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1291** rounded down to the next smaller 1292** multiple of 8. See also: [SQLITE_CONFIG_LOOKASIDE]</dd> 1293** 1294** </dl> 1295*/ 1296#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1297 1298 1299/* 1300** CAPI3REF: Enable Or Disable Extended Result Codes 1301** 1302** ^The sqlite3_extended_result_codes() routine enables or disables the 1303** [extended result codes] feature of SQLite. ^The extended result 1304** codes are disabled by default for historical compatibility. 1305*/ 1306SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff); 1307 1308/* 1309** CAPI3REF: Last Insert Rowid 1310** 1311** ^Each entry in an SQLite table has a unique 64-bit signed 1312** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1313** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1314** names are not also used by explicitly declared columns. ^If 1315** the table has a column of type [INTEGER PRIMARY KEY] then that column 1316** is another alias for the rowid. 1317** 1318** ^This routine returns the [rowid] of the most recent 1319** successful [INSERT] into the database from the [database connection] 1320** in the first argument. ^If no successful [INSERT]s 1321** have ever occurred on that database connection, zero is returned. 1322** 1323** ^(If an [INSERT] occurs within a trigger, then the [rowid] of the inserted 1324** row is returned by this routine as long as the trigger is running. 1325** But once the trigger terminates, the value returned by this routine 1326** reverts to the last value inserted before the trigger fired.)^ 1327** 1328** ^An [INSERT] that fails due to a constraint violation is not a 1329** successful [INSERT] and does not change the value returned by this 1330** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1331** and INSERT OR ABORT make no changes to the return value of this 1332** routine when their insertion fails. ^(When INSERT OR REPLACE 1333** encounters a constraint violation, it does not fail. The 1334** INSERT continues to completion after deleting rows that caused 1335** the constraint problem so INSERT OR REPLACE will always change 1336** the return value of this interface.)^ 1337** 1338** ^For the purposes of this routine, an [INSERT] is considered to 1339** be successful even if it is subsequently rolled back. 1340** 1341** This function is accessible to SQL statements via the 1342** [last_insert_rowid() SQL function]. 1343** 1344** If a separate thread performs a new [INSERT] on the same 1345** database connection while the [sqlite3_last_insert_rowid()] 1346** function is running and thus changes the last insert [rowid], 1347** then the value returned by [sqlite3_last_insert_rowid()] is 1348** unpredictable and might not equal either the old or the new 1349** last insert [rowid]. 1350*/ 1351SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1352 1353/* 1354** CAPI3REF: Count The Number Of Rows Modified 1355** 1356** ^This function returns the number of database rows that were changed 1357** or inserted or deleted by the most recently completed SQL statement 1358** on the [database connection] specified by the first parameter. 1359** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1360** or [DELETE] statement are counted. Auxiliary changes caused by 1361** triggers or [foreign key actions] are not counted.)^ Use the 1362** [sqlite3_total_changes()] function to find the total number of changes 1363** including changes caused by triggers and foreign key actions. 1364** 1365** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1366** are not counted. Only real table changes are counted. 1367** 1368** ^(A "row change" is a change to a single row of a single table 1369** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1370** are changed as side effects of [REPLACE] constraint resolution, 1371** rollback, ABORT processing, [DROP TABLE], or by any other 1372** mechanisms do not count as direct row changes.)^ 1373** 1374** A "trigger context" is a scope of execution that begins and 1375** ends with the script of a [CREATE TRIGGER | trigger]. 1376** Most SQL statements are 1377** evaluated outside of any trigger. This is the "top level" 1378** trigger context. If a trigger fires from the top level, a 1379** new trigger context is entered for the duration of that one 1380** trigger. Subtriggers create subcontexts for their duration. 1381** 1382** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1383** not create a new trigger context. 1384** 1385** ^This function returns the number of direct row changes in the 1386** most recent INSERT, UPDATE, or DELETE statement within the same 1387** trigger context. 1388** 1389** ^Thus, when called from the top level, this function returns the 1390** number of changes in the most recent INSERT, UPDATE, or DELETE 1391** that also occurred at the top level. ^(Within the body of a trigger, 1392** the sqlite3_changes() interface can be called to find the number of 1393** changes in the most recently completed INSERT, UPDATE, or DELETE 1394** statement within the body of the same trigger. 1395** However, the number returned does not include changes 1396** caused by subtriggers since those have their own context.)^ 1397** 1398** See also the [sqlite3_total_changes()] interface, the 1399** [count_changes pragma], and the [changes() SQL function]. 1400** 1401** If a separate thread makes changes on the same database connection 1402** while [sqlite3_changes()] is running then the value returned 1403** is unpredictable and not meaningful. 1404*/ 1405SQLITE_API int sqlite3_changes(sqlite3*); 1406 1407/* 1408** CAPI3REF: Total Number Of Rows Modified 1409** 1410** ^This function returns the number of row changes caused by [INSERT], 1411** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1412** ^(The count returned by sqlite3_total_changes() includes all changes 1413** from all [CREATE TRIGGER | trigger] contexts and changes made by 1414** [foreign key actions]. However, 1415** the count does not include changes used to implement [REPLACE] constraints, 1416** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1417** count does not include rows of views that fire an [INSTEAD OF trigger], 1418** though if the INSTEAD OF trigger makes changes of its own, those changes 1419** are counted.)^ 1420** ^The sqlite3_total_changes() function counts the changes as soon as 1421** the statement that makes them is completed (when the statement handle 1422** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1423** 1424** See also the [sqlite3_changes()] interface, the 1425** [count_changes pragma], and the [total_changes() SQL function]. 1426** 1427** If a separate thread makes changes on the same database connection 1428** while [sqlite3_total_changes()] is running then the value 1429** returned is unpredictable and not meaningful. 1430*/ 1431SQLITE_API int sqlite3_total_changes(sqlite3*); 1432 1433/* 1434** CAPI3REF: Interrupt A Long-Running Query 1435** 1436** ^This function causes any pending database operation to abort and 1437** return at its earliest opportunity. This routine is typically 1438** called in response to a user action such as pressing "Cancel" 1439** or Ctrl-C where the user wants a long query operation to halt 1440** immediately. 1441** 1442** ^It is safe to call this routine from a thread different from the 1443** thread that is currently running the database operation. But it 1444** is not safe to call this routine with a [database connection] that 1445** is closed or might close before sqlite3_interrupt() returns. 1446** 1447** ^If an SQL operation is very nearly finished at the time when 1448** sqlite3_interrupt() is called, then it might not have an opportunity 1449** to be interrupted and might continue to completion. 1450** 1451** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1452** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1453** that is inside an explicit transaction, then the entire transaction 1454** will be rolled back automatically. 1455** 1456** ^The sqlite3_interrupt(D) call is in effect until all currently running 1457** SQL statements on [database connection] D complete. ^Any new SQL statements 1458** that are started after the sqlite3_interrupt() call and before the 1459** running statements reaches zero are interrupted as if they had been 1460** running prior to the sqlite3_interrupt() call. ^New SQL statements 1461** that are started after the running statement count reaches zero are 1462** not effected by the sqlite3_interrupt(). 1463** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1464** SQL statements is a no-op and has no effect on SQL statements 1465** that are started after the sqlite3_interrupt() call returns. 1466** 1467** If the database connection closes while [sqlite3_interrupt()] 1468** is running then bad things will likely happen. 1469*/ 1470SQLITE_API void sqlite3_interrupt(sqlite3*); 1471 1472/* 1473** CAPI3REF: Determine If An SQL Statement Is Complete 1474** 1475** These routines are useful during command-line input to determine if the 1476** currently entered text seems to form a complete SQL statement or 1477** if additional input is needed before sending the text into 1478** SQLite for parsing. ^These routines return 1 if the input string 1479** appears to be a complete SQL statement. ^A statement is judged to be 1480** complete if it ends with a semicolon token and is not a prefix of a 1481** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1482** string literals or quoted identifier names or comments are not 1483** independent tokens (they are part of the token in which they are 1484** embedded) and thus do not count as a statement terminator. ^Whitespace 1485** and comments that follow the final semicolon are ignored. 1486** 1487** ^These routines return 0 if the statement is incomplete. ^If a 1488** memory allocation fails, then SQLITE_NOMEM is returned. 1489** 1490** ^These routines do not parse the SQL statements thus 1491** will not detect syntactically incorrect SQL. 1492** 1493** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1494** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1495** automatically by sqlite3_complete16(). If that initialization fails, 1496** then the return value from sqlite3_complete16() will be non-zero 1497** regardless of whether or not the input SQL is complete.)^ 1498** 1499** The input to [sqlite3_complete()] must be a zero-terminated 1500** UTF-8 string. 1501** 1502** The input to [sqlite3_complete16()] must be a zero-terminated 1503** UTF-16 string in native byte order. 1504*/ 1505SQLITE_API int sqlite3_complete(const char *sql); 1506SQLITE_API int sqlite3_complete16(const void *sql); 1507 1508/* 1509** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1510** 1511** ^This routine sets a callback function that might be invoked whenever 1512** an attempt is made to open a database table that another thread 1513** or process has locked. 1514** 1515** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1516** is returned immediately upon encountering the lock. ^If the busy callback 1517** is not NULL, then the callback might be invoked with two arguments. 1518** 1519** ^The first argument to the busy handler is a copy of the void* pointer which 1520** is the third argument to sqlite3_busy_handler(). ^The second argument to 1521** the busy handler callback is the number of times that the busy handler has 1522** been invoked for this locking event. ^If the 1523** busy callback returns 0, then no additional attempts are made to 1524** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1525** ^If the callback returns non-zero, then another attempt 1526** is made to open the database for reading and the cycle repeats. 1527** 1528** The presence of a busy handler does not guarantee that it will be invoked 1529** when there is lock contention. ^If SQLite determines that invoking the busy 1530** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1531** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1532** Consider a scenario where one process is holding a read lock that 1533** it is trying to promote to a reserved lock and 1534** a second process is holding a reserved lock that it is trying 1535** to promote to an exclusive lock. The first process cannot proceed 1536** because it is blocked by the second and the second process cannot 1537** proceed because it is blocked by the first. If both processes 1538** invoke the busy handlers, neither will make any progress. Therefore, 1539** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1540** will induce the first process to release its read lock and allow 1541** the second process to proceed. 1542** 1543** ^The default busy callback is NULL. 1544** 1545** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1546** when SQLite is in the middle of a large transaction where all the 1547** changes will not fit into the in-memory cache. SQLite will 1548** already hold a RESERVED lock on the database file, but it needs 1549** to promote this lock to EXCLUSIVE so that it can spill cache 1550** pages into the database file without harm to concurrent 1551** readers. ^If it is unable to promote the lock, then the in-memory 1552** cache will be left in an inconsistent state and so the error 1553** code is promoted from the relatively benign [SQLITE_BUSY] to 1554** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 1555** forces an automatic rollback of the changes. See the 1556** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1557** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1558** this is important. 1559** 1560** ^(There can only be a single busy handler defined for each 1561** [database connection]. Setting a new busy handler clears any 1562** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 1563** will also set or clear the busy handler. 1564** 1565** The busy callback should not take any actions which modify the 1566** database connection that invoked the busy handler. Any such actions 1567** result in undefined behavior. 1568** 1569** A busy handler must not close the database connection 1570** or [prepared statement] that invoked the busy handler. 1571*/ 1572SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1573 1574/* 1575** CAPI3REF: Set A Busy Timeout 1576** 1577** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1578** for a specified amount of time when a table is locked. ^The handler 1579** will sleep multiple times until at least "ms" milliseconds of sleeping 1580** have accumulated. ^After at least "ms" milliseconds of sleeping, 1581** the handler returns 0 which causes [sqlite3_step()] to return 1582** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1583** 1584** ^Calling this routine with an argument less than or equal to zero 1585** turns off all busy handlers. 1586** 1587** ^(There can only be a single busy handler for a particular 1588** [database connection] any any given moment. If another busy handler 1589** was defined (using [sqlite3_busy_handler()]) prior to calling 1590** this routine, that other busy handler is cleared.)^ 1591*/ 1592SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms); 1593 1594/* 1595** CAPI3REF: Convenience Routines For Running Queries 1596** 1597** Definition: A <b>result table</b> is memory data structure created by the 1598** [sqlite3_get_table()] interface. A result table records the 1599** complete query results from one or more queries. 1600** 1601** The table conceptually has a number of rows and columns. But 1602** these numbers are not part of the result table itself. These 1603** numbers are obtained separately. Let N be the number of rows 1604** and M be the number of columns. 1605** 1606** A result table is an array of pointers to zero-terminated UTF-8 strings. 1607** There are (N+1)*M elements in the array. The first M pointers point 1608** to zero-terminated strings that contain the names of the columns. 1609** The remaining entries all point to query results. NULL values result 1610** in NULL pointers. All other values are in their UTF-8 zero-terminated 1611** string representation as returned by [sqlite3_column_text()]. 1612** 1613** A result table might consist of one or more memory allocations. 1614** It is not safe to pass a result table directly to [sqlite3_free()]. 1615** A result table should be deallocated using [sqlite3_free_table()]. 1616** 1617** As an example of the result table format, suppose a query result 1618** is as follows: 1619** 1620** <blockquote><pre> 1621** Name | Age 1622** ----------------------- 1623** Alice | 43 1624** Bob | 28 1625** Cindy | 21 1626** </pre></blockquote> 1627** 1628** There are two column (M==2) and three rows (N==3). Thus the 1629** result table has 8 entries. Suppose the result table is stored 1630** in an array names azResult. Then azResult holds this content: 1631** 1632** <blockquote><pre> 1633** azResult[0] = "Name"; 1634** azResult[1] = "Age"; 1635** azResult[2] = "Alice"; 1636** azResult[3] = "43"; 1637** azResult[4] = "Bob"; 1638** azResult[5] = "28"; 1639** azResult[6] = "Cindy"; 1640** azResult[7] = "21"; 1641** </pre></blockquote> 1642** 1643** ^The sqlite3_get_table() function evaluates one or more 1644** semicolon-separated SQL statements in the zero-terminated UTF-8 1645** string of its 2nd parameter and returns a result table to the 1646** pointer given in its 3rd parameter. 1647** 1648** After the application has finished with the result from sqlite3_get_table(), 1649** it should pass the result table pointer to sqlite3_free_table() in order to 1650** release the memory that was malloced. Because of the way the 1651** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1652** function must not try to call [sqlite3_free()] directly. Only 1653** [sqlite3_free_table()] is able to release the memory properly and safely. 1654** 1655** ^(The sqlite3_get_table() interface is implemented as a wrapper around 1656** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 1657** to any internal data structures of SQLite. It uses only the public 1658** interface defined here. As a consequence, errors that occur in the 1659** wrapper layer outside of the internal [sqlite3_exec()] call are not 1660** reflected in subsequent calls to [sqlite3_errcode()] or 1661** [sqlite3_errmsg()].)^ 1662*/ 1663SQLITE_API int sqlite3_get_table( 1664 sqlite3 *db, /* An open database */ 1665 const char *zSql, /* SQL to be evaluated */ 1666 char ***pazResult, /* Results of the query */ 1667 int *pnRow, /* Number of result rows written here */ 1668 int *pnColumn, /* Number of result columns written here */ 1669 char **pzErrmsg /* Error msg written here */ 1670); 1671SQLITE_API void sqlite3_free_table(char **result); 1672 1673/* 1674** CAPI3REF: Formatted String Printing Functions 1675** 1676** These routines are work-alikes of the "printf()" family of functions 1677** from the standard C library. 1678** 1679** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 1680** results into memory obtained from [sqlite3_malloc()]. 1681** The strings returned by these two routines should be 1682** released by [sqlite3_free()]. ^Both routines return a 1683** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 1684** memory to hold the resulting string. 1685** 1686** ^(In sqlite3_snprintf() routine is similar to "snprintf()" from 1687** the standard C library. The result is written into the 1688** buffer supplied as the second parameter whose size is given by 1689** the first parameter. Note that the order of the 1690** first two parameters is reversed from snprintf().)^ This is an 1691** historical accident that cannot be fixed without breaking 1692** backwards compatibility. ^(Note also that sqlite3_snprintf() 1693** returns a pointer to its buffer instead of the number of 1694** characters actually written into the buffer.)^ We admit that 1695** the number of characters written would be a more useful return 1696** value but we cannot change the implementation of sqlite3_snprintf() 1697** now without breaking compatibility. 1698** 1699** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 1700** guarantees that the buffer is always zero-terminated. ^The first 1701** parameter "n" is the total size of the buffer, including space for 1702** the zero terminator. So the longest string that can be completely 1703** written will be n-1 characters. 1704** 1705** These routines all implement some additional formatting 1706** options that are useful for constructing SQL statements. 1707** All of the usual printf() formatting options apply. In addition, there 1708** is are "%q", "%Q", and "%z" options. 1709** 1710** ^(The %q option works like %s in that it substitutes a null-terminated 1711** string from the argument list. But %q also doubles every '\'' character. 1712** %q is designed for use inside a string literal.)^ By doubling each '\'' 1713** character it escapes that character and allows it to be inserted into 1714** the string. 1715** 1716** For example, assume the string variable zText contains text as follows: 1717** 1718** <blockquote><pre> 1719** char *zText = "It's a happy day!"; 1720** </pre></blockquote> 1721** 1722** One can use this text in an SQL statement as follows: 1723** 1724** <blockquote><pre> 1725** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 1726** sqlite3_exec(db, zSQL, 0, 0, 0); 1727** sqlite3_free(zSQL); 1728** </pre></blockquote> 1729** 1730** Because the %q format string is used, the '\'' character in zText 1731** is escaped and the SQL generated is as follows: 1732** 1733** <blockquote><pre> 1734** INSERT INTO table1 VALUES('It''s a happy day!') 1735** </pre></blockquote> 1736** 1737** This is correct. Had we used %s instead of %q, the generated SQL 1738** would have looked like this: 1739** 1740** <blockquote><pre> 1741** INSERT INTO table1 VALUES('It's a happy day!'); 1742** </pre></blockquote> 1743** 1744** This second example is an SQL syntax error. As a general rule you should 1745** always use %q instead of %s when inserting text into a string literal. 1746** 1747** ^(The %Q option works like %q except it also adds single quotes around 1748** the outside of the total string. Additionally, if the parameter in the 1749** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 1750** single quotes).)^ So, for example, one could say: 1751** 1752** <blockquote><pre> 1753** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 1754** sqlite3_exec(db, zSQL, 0, 0, 0); 1755** sqlite3_free(zSQL); 1756** </pre></blockquote> 1757** 1758** The code above will render a correct SQL statement in the zSQL 1759** variable even if the zText variable is a NULL pointer. 1760** 1761** ^(The "%z" formatting option works like "%s" but with the 1762** addition that after the string has been read and copied into 1763** the result, [sqlite3_free()] is called on the input string.)^ 1764*/ 1765SQLITE_API char *sqlite3_mprintf(const char*,...); 1766SQLITE_API char *sqlite3_vmprintf(const char*, va_list); 1767SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...); 1768 1769/* 1770** CAPI3REF: Memory Allocation Subsystem 1771** 1772** The SQLite core uses these three routines for all of its own 1773** internal memory allocation needs. "Core" in the previous sentence 1774** does not include operating-system specific VFS implementation. The 1775** Windows VFS uses native malloc() and free() for some operations. 1776** 1777** ^The sqlite3_malloc() routine returns a pointer to a block 1778** of memory at least N bytes in length, where N is the parameter. 1779** ^If sqlite3_malloc() is unable to obtain sufficient free 1780** memory, it returns a NULL pointer. ^If the parameter N to 1781** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 1782** a NULL pointer. 1783** 1784** ^Calling sqlite3_free() with a pointer previously returned 1785** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 1786** that it might be reused. ^The sqlite3_free() routine is 1787** a no-op if is called with a NULL pointer. Passing a NULL pointer 1788** to sqlite3_free() is harmless. After being freed, memory 1789** should neither be read nor written. Even reading previously freed 1790** memory might result in a segmentation fault or other severe error. 1791** Memory corruption, a segmentation fault, or other severe error 1792** might result if sqlite3_free() is called with a non-NULL pointer that 1793** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 1794** 1795** ^(The sqlite3_realloc() interface attempts to resize a 1796** prior memory allocation to be at least N bytes, where N is the 1797** second parameter. The memory allocation to be resized is the first 1798** parameter.)^ ^ If the first parameter to sqlite3_realloc() 1799** is a NULL pointer then its behavior is identical to calling 1800** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 1801** ^If the second parameter to sqlite3_realloc() is zero or 1802** negative then the behavior is exactly the same as calling 1803** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 1804** ^sqlite3_realloc() returns a pointer to a memory allocation 1805** of at least N bytes in size or NULL if sufficient memory is unavailable. 1806** ^If M is the size of the prior allocation, then min(N,M) bytes 1807** of the prior allocation are copied into the beginning of buffer returned 1808** by sqlite3_realloc() and the prior allocation is freed. 1809** ^If sqlite3_realloc() returns NULL, then the prior allocation 1810** is not freed. 1811** 1812** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 1813** is always aligned to at least an 8 byte boundary. 1814** 1815** In SQLite version 3.5.0 and 3.5.1, it was possible to define 1816** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 1817** implementation of these routines to be omitted. That capability 1818** is no longer provided. Only built-in memory allocators can be used. 1819** 1820** The Windows OS interface layer calls 1821** the system malloc() and free() directly when converting 1822** filenames between the UTF-8 encoding used by SQLite 1823** and whatever filename encoding is used by the particular Windows 1824** installation. Memory allocation errors are detected, but 1825** they are reported back as [SQLITE_CANTOPEN] or 1826** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 1827** 1828** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 1829** must be either NULL or else pointers obtained from a prior 1830** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 1831** not yet been released. 1832** 1833** The application must not read or write any part of 1834** a block of memory after it has been released using 1835** [sqlite3_free()] or [sqlite3_realloc()]. 1836*/ 1837SQLITE_API void *sqlite3_malloc(int); 1838SQLITE_API void *sqlite3_realloc(void*, int); 1839SQLITE_API void sqlite3_free(void*); 1840 1841/* 1842** CAPI3REF: Memory Allocator Statistics 1843** 1844** SQLite provides these two interfaces for reporting on the status 1845** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 1846** routines, which form the built-in memory allocation subsystem. 1847** 1848** ^The [sqlite3_memory_used()] routine returns the number of bytes 1849** of memory currently outstanding (malloced but not freed). 1850** ^The [sqlite3_memory_highwater()] routine returns the maximum 1851** value of [sqlite3_memory_used()] since the high-water mark 1852** was last reset. ^The values returned by [sqlite3_memory_used()] and 1853** [sqlite3_memory_highwater()] include any overhead 1854** added by SQLite in its implementation of [sqlite3_malloc()], 1855** but not overhead added by the any underlying system library 1856** routines that [sqlite3_malloc()] may call. 1857** 1858** ^The memory high-water mark is reset to the current value of 1859** [sqlite3_memory_used()] if and only if the parameter to 1860** [sqlite3_memory_highwater()] is true. ^The value returned 1861** by [sqlite3_memory_highwater(1)] is the high-water mark 1862** prior to the reset. 1863*/ 1864SQLITE_API sqlite3_int64 sqlite3_memory_used(void); 1865SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 1866 1867/* 1868** CAPI3REF: Pseudo-Random Number Generator 1869** 1870** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 1871** select random [ROWID | ROWIDs] when inserting new records into a table that 1872** already uses the largest possible [ROWID]. The PRNG is also used for 1873** the build-in random() and randomblob() SQL functions. This interface allows 1874** applications to access the same PRNG for other purposes. 1875** 1876** ^A call to this routine stores N bytes of randomness into buffer P. 1877** 1878** ^The first time this routine is invoked (either internally or by 1879** the application) the PRNG is seeded using randomness obtained 1880** from the xRandomness method of the default [sqlite3_vfs] object. 1881** ^On all subsequent invocations, the pseudo-randomness is generated 1882** internally and without recourse to the [sqlite3_vfs] xRandomness 1883** method. 1884*/ 1885SQLITE_API void sqlite3_randomness(int N, void *P); 1886 1887/* 1888** CAPI3REF: Compile-Time Authorization Callbacks 1889** 1890** ^This routine registers a authorizer callback with a particular 1891** [database connection], supplied in the first argument. 1892** ^The authorizer callback is invoked as SQL statements are being compiled 1893** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 1894** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 1895** points during the compilation process, as logic is being created 1896** to perform various actions, the authorizer callback is invoked to 1897** see if those actions are allowed. ^The authorizer callback should 1898** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 1899** specific action but allow the SQL statement to continue to be 1900** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 1901** rejected with an error. ^If the authorizer callback returns 1902** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 1903** then the [sqlite3_prepare_v2()] or equivalent call that triggered 1904** the authorizer will fail with an error message. 1905** 1906** When the callback returns [SQLITE_OK], that means the operation 1907** requested is ok. ^When the callback returns [SQLITE_DENY], the 1908** [sqlite3_prepare_v2()] or equivalent call that triggered the 1909** authorizer will fail with an error message explaining that 1910** access is denied. 1911** 1912** ^The first parameter to the authorizer callback is a copy of the third 1913** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 1914** to the callback is an integer [SQLITE_COPY | action code] that specifies 1915** the particular action to be authorized. ^The third through sixth parameters 1916** to the callback are zero-terminated strings that contain additional 1917** details about the action to be authorized. 1918** 1919** ^If the action code is [SQLITE_READ] 1920** and the callback returns [SQLITE_IGNORE] then the 1921** [prepared statement] statement is constructed to substitute 1922** a NULL value in place of the table column that would have 1923** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 1924** return can be used to deny an untrusted user access to individual 1925** columns of a table. 1926** ^If the action code is [SQLITE_DELETE] and the callback returns 1927** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 1928** [truncate optimization] is disabled and all rows are deleted individually. 1929** 1930** An authorizer is used when [sqlite3_prepare | preparing] 1931** SQL statements from an untrusted source, to ensure that the SQL statements 1932** do not try to access data they are not allowed to see, or that they do not 1933** try to execute malicious statements that damage the database. For 1934** example, an application may allow a user to enter arbitrary 1935** SQL queries for evaluation by a database. But the application does 1936** not want the user to be able to make arbitrary changes to the 1937** database. An authorizer could then be put in place while the 1938** user-entered SQL is being [sqlite3_prepare | prepared] that 1939** disallows everything except [SELECT] statements. 1940** 1941** Applications that need to process SQL from untrusted sources 1942** might also consider lowering resource limits using [sqlite3_limit()] 1943** and limiting database size using the [max_page_count] [PRAGMA] 1944** in addition to using an authorizer. 1945** 1946** ^(Only a single authorizer can be in place on a database connection 1947** at a time. Each call to sqlite3_set_authorizer overrides the 1948** previous call.)^ ^Disable the authorizer by installing a NULL callback. 1949** The authorizer is disabled by default. 1950** 1951** The authorizer callback must not do anything that will modify 1952** the database connection that invoked the authorizer callback. 1953** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 1954** database connections for the meaning of "modify" in this paragraph. 1955** 1956** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 1957** statement might be re-prepared during [sqlite3_step()] due to a 1958** schema change. Hence, the application should ensure that the 1959** correct authorizer callback remains in place during the [sqlite3_step()]. 1960** 1961** ^Note that the authorizer callback is invoked only during 1962** [sqlite3_prepare()] or its variants. Authorization is not 1963** performed during statement evaluation in [sqlite3_step()], unless 1964** as stated in the previous paragraph, sqlite3_step() invokes 1965** sqlite3_prepare_v2() to reprepare a statement after a schema change. 1966*/ 1967SQLITE_API int sqlite3_set_authorizer( 1968 sqlite3*, 1969 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 1970 void *pUserData 1971); 1972 1973/* 1974** CAPI3REF: Authorizer Return Codes 1975** 1976** The [sqlite3_set_authorizer | authorizer callback function] must 1977** return either [SQLITE_OK] or one of these two constants in order 1978** to signal SQLite whether or not the action is permitted. See the 1979** [sqlite3_set_authorizer | authorizer documentation] for additional 1980** information. 1981*/ 1982#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 1983#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 1984 1985/* 1986** CAPI3REF: Authorizer Action Codes 1987** 1988** The [sqlite3_set_authorizer()] interface registers a callback function 1989** that is invoked to authorize certain SQL statement actions. The 1990** second parameter to the callback is an integer code that specifies 1991** what action is being authorized. These are the integer action codes that 1992** the authorizer callback may be passed. 1993** 1994** These action code values signify what kind of operation is to be 1995** authorized. The 3rd and 4th parameters to the authorization 1996** callback function will be parameters or NULL depending on which of these 1997** codes is used as the second parameter. ^(The 5th parameter to the 1998** authorizer callback is the name of the database ("main", "temp", 1999** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2000** is the name of the inner-most trigger or view that is responsible for 2001** the access attempt or NULL if this access attempt is directly from 2002** top-level SQL code. 2003*/ 2004/******************************************* 3rd ************ 4th ***********/ 2005#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2006#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2007#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2008#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2009#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2010#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2011#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2012#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2013#define SQLITE_DELETE 9 /* Table Name NULL */ 2014#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2015#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2016#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2017#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2018#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2019#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2020#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2021#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2022#define SQLITE_INSERT 18 /* Table Name NULL */ 2023#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2024#define SQLITE_READ 20 /* Table Name Column Name */ 2025#define SQLITE_SELECT 21 /* NULL NULL */ 2026#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2027#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2028#define SQLITE_ATTACH 24 /* Filename NULL */ 2029#define SQLITE_DETACH 25 /* Database Name NULL */ 2030#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2031#define SQLITE_REINDEX 27 /* Index Name NULL */ 2032#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2033#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2034#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2035#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2036#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2037#define SQLITE_COPY 0 /* No longer used */ 2038 2039/* 2040** CAPI3REF: Tracing And Profiling Functions 2041** EXPERIMENTAL 2042** 2043** These routines register callback functions that can be used for 2044** tracing and profiling the execution of SQL statements. 2045** 2046** ^The callback function registered by sqlite3_trace() is invoked at 2047** various times when an SQL statement is being run by [sqlite3_step()]. 2048** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2049** SQL statement text as the statement first begins executing. 2050** ^(Additional sqlite3_trace() callbacks might occur 2051** as each triggered subprogram is entered. The callbacks for triggers 2052** contain a UTF-8 SQL comment that identifies the trigger.)^ 2053** 2054** ^The callback function registered by sqlite3_profile() is invoked 2055** as each SQL statement finishes. ^The profile callback contains 2056** the original statement text and an estimate of wall-clock time 2057** of how long that statement took to run. 2058*/ 2059SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2060SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2061 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2062 2063/* 2064** CAPI3REF: Query Progress Callbacks 2065** 2066** ^This routine configures a callback function - the 2067** progress callback - that is invoked periodically during long 2068** running calls to [sqlite3_exec()], [sqlite3_step()] and 2069** [sqlite3_get_table()]. An example use for this 2070** interface is to keep a GUI updated during a large query. 2071** 2072** ^If the progress callback returns non-zero, the operation is 2073** interrupted. This feature can be used to implement a 2074** "Cancel" button on a GUI progress dialog box. 2075** 2076** The progress handler must not do anything that will modify 2077** the database connection that invoked the progress handler. 2078** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2079** database connections for the meaning of "modify" in this paragraph. 2080** 2081*/ 2082SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2083 2084/* 2085** CAPI3REF: Opening A New Database Connection 2086** 2087** ^These routines open an SQLite database file whose name is given by the 2088** filename argument. ^The filename argument is interpreted as UTF-8 for 2089** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2090** order for sqlite3_open16(). ^(A [database connection] handle is usually 2091** returned in *ppDb, even if an error occurs. The only exception is that 2092** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2093** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2094** object.)^ ^(If the database is opened (and/or created) successfully, then 2095** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2096** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2097** an English language description of the error following a failure of any 2098** of the sqlite3_open() routines. 2099** 2100** ^The default encoding for the database will be UTF-8 if 2101** sqlite3_open() or sqlite3_open_v2() is called and 2102** UTF-16 in the native byte order if sqlite3_open16() is used. 2103** 2104** Whether or not an error occurs when it is opened, resources 2105** associated with the [database connection] handle should be released by 2106** passing it to [sqlite3_close()] when it is no longer required. 2107** 2108** The sqlite3_open_v2() interface works like sqlite3_open() 2109** except that it accepts two additional parameters for additional control 2110** over the new database connection. ^(The flags parameter to 2111** sqlite3_open_v2() can take one of 2112** the following three values, optionally combined with the 2113** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2114** and/or [SQLITE_OPEN_PRIVATECACHE] flags:)^ 2115** 2116** <dl> 2117** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2118** <dd>The database is opened in read-only mode. If the database does not 2119** already exist, an error is returned.</dd>)^ 2120** 2121** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2122** <dd>The database is opened for reading and writing if possible, or reading 2123** only if the file is write protected by the operating system. In either 2124** case the database must already exist, otherwise an error is returned.</dd>)^ 2125** 2126** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2127** <dd>The database is opened for reading and writing, and is creates it if 2128** it does not already exist. This is the behavior that is always used for 2129** sqlite3_open() and sqlite3_open16().</dd>)^ 2130** </dl> 2131** 2132** If the 3rd parameter to sqlite3_open_v2() is not one of the 2133** combinations shown above or one of the combinations shown above combined 2134** with the [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], 2135** [SQLITE_OPEN_SHAREDCACHE] and/or [SQLITE_OPEN_SHAREDCACHE] flags, 2136** then the behavior is undefined. 2137** 2138** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2139** opens in the multi-thread [threading mode] as long as the single-thread 2140** mode has not been set at compile-time or start-time. ^If the 2141** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2142** in the serialized [threading mode] unless single-thread was 2143** previously selected at compile-time or start-time. 2144** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2145** eligible to use [shared cache mode], regardless of whether or not shared 2146** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2147** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2148** participate in [shared cache mode] even if it is enabled. 2149** 2150** ^If the filename is ":memory:", then a private, temporary in-memory database 2151** is created for the connection. ^This in-memory database will vanish when 2152** the database connection is closed. Future versions of SQLite might 2153** make use of additional special filenames that begin with the ":" character. 2154** It is recommended that when a database filename actually does begin with 2155** a ":" character you should prefix the filename with a pathname such as 2156** "./" to avoid ambiguity. 2157** 2158** ^If the filename is an empty string, then a private, temporary 2159** on-disk database will be created. ^This private database will be 2160** automatically deleted as soon as the database connection is closed. 2161** 2162** ^The fourth parameter to sqlite3_open_v2() is the name of the 2163** [sqlite3_vfs] object that defines the operating system interface that 2164** the new database connection should use. ^If the fourth parameter is 2165** a NULL pointer then the default [sqlite3_vfs] object is used. 2166** 2167** <b>Note to Windows users:</b> The encoding used for the filename argument 2168** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2169** codepage is currently defined. Filenames containing international 2170** characters must be converted to UTF-8 prior to passing them into 2171** sqlite3_open() or sqlite3_open_v2(). 2172*/ 2173SQLITE_API int sqlite3_open( 2174 const char *filename, /* Database filename (UTF-8) */ 2175 sqlite3 **ppDb /* OUT: SQLite db handle */ 2176); 2177SQLITE_API int sqlite3_open16( 2178 const void *filename, /* Database filename (UTF-16) */ 2179 sqlite3 **ppDb /* OUT: SQLite db handle */ 2180); 2181SQLITE_API int sqlite3_open_v2( 2182 const char *filename, /* Database filename (UTF-8) */ 2183 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2184 int flags, /* Flags */ 2185 const char *zVfs /* Name of VFS module to use */ 2186); 2187 2188/* 2189** CAPI3REF: Error Codes And Messages 2190** 2191** ^The sqlite3_errcode() interface returns the numeric [result code] or 2192** [extended result code] for the most recent failed sqlite3_* API call 2193** associated with a [database connection]. If a prior API call failed 2194** but the most recent API call succeeded, the return value from 2195** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2196** interface is the same except that it always returns the 2197** [extended result code] even when extended result codes are 2198** disabled. 2199** 2200** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2201** text that describes the error, as either UTF-8 or UTF-16 respectively. 2202** ^(Memory to hold the error message string is managed internally. 2203** The application does not need to worry about freeing the result. 2204** However, the error string might be overwritten or deallocated by 2205** subsequent calls to other SQLite interface functions.)^ 2206** 2207** When the serialized [threading mode] is in use, it might be the 2208** case that a second error occurs on a separate thread in between 2209** the time of the first error and the call to these interfaces. 2210** When that happens, the second error will be reported since these 2211** interfaces always report the most recent result. To avoid 2212** this, each thread can obtain exclusive use of the [database connection] D 2213** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2214** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2215** all calls to the interfaces listed here are completed. 2216** 2217** If an interface fails with SQLITE_MISUSE, that means the interface 2218** was invoked incorrectly by the application. In that case, the 2219** error code and message may or may not be set. 2220*/ 2221SQLITE_API int sqlite3_errcode(sqlite3 *db); 2222SQLITE_API int sqlite3_extended_errcode(sqlite3 *db); 2223SQLITE_API const char *sqlite3_errmsg(sqlite3*); 2224SQLITE_API const void *sqlite3_errmsg16(sqlite3*); 2225 2226/* 2227** CAPI3REF: SQL Statement Object 2228** KEYWORDS: {prepared statement} {prepared statements} 2229** 2230** An instance of this object represents a single SQL statement. 2231** This object is variously known as a "prepared statement" or a 2232** "compiled SQL statement" or simply as a "statement". 2233** 2234** The life of a statement object goes something like this: 2235** 2236** <ol> 2237** <li> Create the object using [sqlite3_prepare_v2()] or a related 2238** function. 2239** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2240** interfaces. 2241** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2242** <li> Reset the statement using [sqlite3_reset()] then go back 2243** to step 2. Do this zero or more times. 2244** <li> Destroy the object using [sqlite3_finalize()]. 2245** </ol> 2246** 2247** Refer to documentation on individual methods above for additional 2248** information. 2249*/ 2250typedef struct sqlite3_stmt sqlite3_stmt; 2251 2252/* 2253** CAPI3REF: Run-time Limits 2254** 2255** ^(This interface allows the size of various constructs to be limited 2256** on a connection by connection basis. The first parameter is the 2257** [database connection] whose limit is to be set or queried. The 2258** second parameter is one of the [limit categories] that define a 2259** class of constructs to be size limited. The third parameter is the 2260** new limit for that construct. The function returns the old limit.)^ 2261** 2262** ^If the new limit is a negative number, the limit is unchanged. 2263** ^(For the limit category of SQLITE_LIMIT_XYZ there is a 2264** [limits | hard upper bound] 2265** set by a compile-time C preprocessor macro named 2266** [limits | SQLITE_MAX_XYZ]. 2267** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2268** ^Attempts to increase a limit above its hard upper bound are 2269** silently truncated to the hard upper bound. 2270** 2271** Run-time limits are intended for use in applications that manage 2272** both their own internal database and also databases that are controlled 2273** by untrusted external sources. An example application might be a 2274** web browser that has its own databases for storing history and 2275** separate databases controlled by JavaScript applications downloaded 2276** off the Internet. The internal databases can be given the 2277** large, default limits. Databases managed by external sources can 2278** be given much smaller limits designed to prevent a denial of service 2279** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2280** interface to further control untrusted SQL. The size of the database 2281** created by an untrusted script can be contained using the 2282** [max_page_count] [PRAGMA]. 2283** 2284** New run-time limit categories may be added in future releases. 2285*/ 2286SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal); 2287 2288/* 2289** CAPI3REF: Run-Time Limit Categories 2290** KEYWORDS: {limit category} {*limit categories} 2291** 2292** These constants define various performance limits 2293** that can be lowered at run-time using [sqlite3_limit()]. 2294** The synopsis of the meanings of the various limits is shown below. 2295** Additional information is available at [limits | Limits in SQLite]. 2296** 2297** <dl> 2298** ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2299** <dd>The maximum size of any string or BLOB or table row.<dd>)^ 2300** 2301** ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2302** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2303** 2304** ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2305** <dd>The maximum number of columns in a table definition or in the 2306** result set of a [SELECT] or the maximum number of columns in an index 2307** or in an ORDER BY or GROUP BY clause.</dd>)^ 2308** 2309** ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2310** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2311** 2312** ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2313** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2314** 2315** ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2316** <dd>The maximum number of instructions in a virtual machine program 2317** used to implement an SQL statement.</dd>)^ 2318** 2319** ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2320** <dd>The maximum number of arguments on a function.</dd>)^ 2321** 2322** ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2323** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2324** 2325** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2326** <dd>The maximum length of the pattern argument to the [LIKE] or 2327** [GLOB] operators.</dd>)^ 2328** 2329** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2330** <dd>The maximum number of variables in an SQL statement that can 2331** be bound.</dd>)^ 2332** 2333** ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2334** <dd>The maximum depth of recursion for triggers.</dd>)^ 2335** </dl> 2336*/ 2337#define SQLITE_LIMIT_LENGTH 0 2338#define SQLITE_LIMIT_SQL_LENGTH 1 2339#define SQLITE_LIMIT_COLUMN 2 2340#define SQLITE_LIMIT_EXPR_DEPTH 3 2341#define SQLITE_LIMIT_COMPOUND_SELECT 4 2342#define SQLITE_LIMIT_VDBE_OP 5 2343#define SQLITE_LIMIT_FUNCTION_ARG 6 2344#define SQLITE_LIMIT_ATTACHED 7 2345#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2346#define SQLITE_LIMIT_VARIABLE_NUMBER 9 2347#define SQLITE_LIMIT_TRIGGER_DEPTH 10 2348 2349/* 2350** CAPI3REF: Compiling An SQL Statement 2351** KEYWORDS: {SQL statement compiler} 2352** 2353** To execute an SQL query, it must first be compiled into a byte-code 2354** program using one of these routines. 2355** 2356** The first argument, "db", is a [database connection] obtained from a 2357** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2358** [sqlite3_open16()]. The database connection must not have been closed. 2359** 2360** The second argument, "zSql", is the statement to be compiled, encoded 2361** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2362** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2363** use UTF-16. 2364** 2365** ^If the nByte argument is less than zero, then zSql is read up to the 2366** first zero terminator. ^If nByte is non-negative, then it is the maximum 2367** number of bytes read from zSql. ^When nByte is non-negative, the 2368** zSql string ends at either the first '\000' or '\u0000' character or 2369** the nByte-th byte, whichever comes first. If the caller knows 2370** that the supplied string is nul-terminated, then there is a small 2371** performance advantage to be gained by passing an nByte parameter that 2372** is equal to the number of bytes in the input string <i>including</i> 2373** the nul-terminator bytes. 2374** 2375** ^If pzTail is not NULL then *pzTail is made to point to the first byte 2376** past the end of the first SQL statement in zSql. These routines only 2377** compile the first statement in zSql, so *pzTail is left pointing to 2378** what remains uncompiled. 2379** 2380** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 2381** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 2382** to NULL. ^If the input text contains no SQL (if the input is an empty 2383** string or a comment) then *ppStmt is set to NULL. 2384** The calling procedure is responsible for deleting the compiled 2385** SQL statement using [sqlite3_finalize()] after it has finished with it. 2386** ppStmt may not be NULL. 2387** 2388** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 2389** otherwise an [error code] is returned. 2390** 2391** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2392** recommended for all new programs. The two older interfaces are retained 2393** for backwards compatibility, but their use is discouraged. 2394** ^In the "v2" interfaces, the prepared statement 2395** that is returned (the [sqlite3_stmt] object) contains a copy of the 2396** original SQL text. This causes the [sqlite3_step()] interface to 2397** behave differently in three ways: 2398** 2399** <ol> 2400** <li> 2401** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2402** always used to do, [sqlite3_step()] will automatically recompile the SQL 2403** statement and try to run it again. ^If the schema has changed in 2404** a way that makes the statement no longer valid, [sqlite3_step()] will still 2405** return [SQLITE_SCHEMA]. But unlike the legacy behavior, [SQLITE_SCHEMA] is 2406** now a fatal error. Calling [sqlite3_prepare_v2()] again will not make the 2407** error go away. Note: use [sqlite3_errmsg()] to find the text 2408** of the parsing error that results in an [SQLITE_SCHEMA] return. 2409** </li> 2410** 2411** <li> 2412** ^When an error occurs, [sqlite3_step()] will return one of the detailed 2413** [error codes] or [extended error codes]. ^The legacy behavior was that 2414** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2415** and the application would have to make a second call to [sqlite3_reset()] 2416** in order to find the underlying cause of the problem. With the "v2" prepare 2417** interfaces, the underlying reason for the error is returned immediately. 2418** </li> 2419** 2420** <li> 2421** ^If the value of a [parameter | host parameter] in the WHERE clause might 2422** change the query plan for a statement, then the statement may be 2423** automatically recompiled (as if there had been a schema change) on the first 2424** [sqlite3_step()] call following any change to the 2425** [sqlite3_bind_text | bindings] of the [parameter]. 2426** </li> 2427** </ol> 2428*/ 2429SQLITE_API int sqlite3_prepare( 2430 sqlite3 *db, /* Database handle */ 2431 const char *zSql, /* SQL statement, UTF-8 encoded */ 2432 int nByte, /* Maximum length of zSql in bytes. */ 2433 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2434 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2435); 2436SQLITE_API int sqlite3_prepare_v2( 2437 sqlite3 *db, /* Database handle */ 2438 const char *zSql, /* SQL statement, UTF-8 encoded */ 2439 int nByte, /* Maximum length of zSql in bytes. */ 2440 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2441 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2442); 2443SQLITE_API int sqlite3_prepare16( 2444 sqlite3 *db, /* Database handle */ 2445 const void *zSql, /* SQL statement, UTF-16 encoded */ 2446 int nByte, /* Maximum length of zSql in bytes. */ 2447 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2448 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2449); 2450SQLITE_API int sqlite3_prepare16_v2( 2451 sqlite3 *db, /* Database handle */ 2452 const void *zSql, /* SQL statement, UTF-16 encoded */ 2453 int nByte, /* Maximum length of zSql in bytes. */ 2454 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2455 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2456); 2457 2458/* 2459** CAPI3REF: Retrieving Statement SQL 2460** 2461** ^This interface can be used to retrieve a saved copy of the original 2462** SQL text used to create a [prepared statement] if that statement was 2463** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2464*/ 2465SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt); 2466 2467/* 2468** CAPI3REF: Dynamically Typed Value Object 2469** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 2470** 2471** SQLite uses the sqlite3_value object to represent all values 2472** that can be stored in a database table. SQLite uses dynamic typing 2473** for the values it stores. ^Values stored in sqlite3_value objects 2474** can be integers, floating point values, strings, BLOBs, or NULL. 2475** 2476** An sqlite3_value object may be either "protected" or "unprotected". 2477** Some interfaces require a protected sqlite3_value. Other interfaces 2478** will accept either a protected or an unprotected sqlite3_value. 2479** Every interface that accepts sqlite3_value arguments specifies 2480** whether or not it requires a protected sqlite3_value. 2481** 2482** The terms "protected" and "unprotected" refer to whether or not 2483** a mutex is held. A internal mutex is held for a protected 2484** sqlite3_value object but no mutex is held for an unprotected 2485** sqlite3_value object. If SQLite is compiled to be single-threaded 2486** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 2487** or if SQLite is run in one of reduced mutex modes 2488** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 2489** then there is no distinction between protected and unprotected 2490** sqlite3_value objects and they can be used interchangeably. However, 2491** for maximum code portability it is recommended that applications 2492** still make the distinction between between protected and unprotected 2493** sqlite3_value objects even when not strictly required. 2494** 2495** ^The sqlite3_value objects that are passed as parameters into the 2496** implementation of [application-defined SQL functions] are protected. 2497** ^The sqlite3_value object returned by 2498** [sqlite3_column_value()] is unprotected. 2499** Unprotected sqlite3_value objects may only be used with 2500** [sqlite3_result_value()] and [sqlite3_bind_value()]. 2501** The [sqlite3_value_blob | sqlite3_value_type()] family of 2502** interfaces require protected sqlite3_value objects. 2503*/ 2504typedef struct Mem sqlite3_value; 2505 2506/* 2507** CAPI3REF: SQL Function Context Object 2508** 2509** The context in which an SQL function executes is stored in an 2510** sqlite3_context object. ^A pointer to an sqlite3_context object 2511** is always first parameter to [application-defined SQL functions]. 2512** The application-defined SQL function implementation will pass this 2513** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 2514** [sqlite3_aggregate_context()], [sqlite3_user_data()], 2515** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 2516** and/or [sqlite3_set_auxdata()]. 2517*/ 2518typedef struct sqlite3_context sqlite3_context; 2519 2520/* 2521** CAPI3REF: Binding Values To Prepared Statements 2522** KEYWORDS: {host parameter} {host parameters} {host parameter name} 2523** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 2524** 2525** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 2526** literals may be replaced by a [parameter] that matches one of following 2527** templates: 2528** 2529** <ul> 2530** <li> ? 2531** <li> ?NNN 2532** <li> :VVV 2533** <li> @VVV 2534** <li> $VVV 2535** </ul> 2536** 2537** In the templates above, NNN represents an integer literal, 2538** and VVV represents an alphanumeric identifer.)^ ^The values of these 2539** parameters (also called "host parameter names" or "SQL parameters") 2540** can be set using the sqlite3_bind_*() routines defined here. 2541** 2542** ^The first argument to the sqlite3_bind_*() routines is always 2543** a pointer to the [sqlite3_stmt] object returned from 2544** [sqlite3_prepare_v2()] or its variants. 2545** 2546** ^The second argument is the index of the SQL parameter to be set. 2547** ^The leftmost SQL parameter has an index of 1. ^When the same named 2548** SQL parameter is used more than once, second and subsequent 2549** occurrences have the same index as the first occurrence. 2550** ^The index for named parameters can be looked up using the 2551** [sqlite3_bind_parameter_index()] API if desired. ^The index 2552** for "?NNN" parameters is the value of NNN. 2553** ^The NNN value must be between 1 and the [sqlite3_limit()] 2554** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 2555** 2556** ^The third argument is the value to bind to the parameter. 2557** 2558** ^(In those routines that have a fourth argument, its value is the 2559** number of bytes in the parameter. To be clear: the value is the 2560** number of <u>bytes</u> in the value, not the number of characters.)^ 2561** ^If the fourth parameter is negative, the length of the string is 2562** the number of bytes up to the first zero terminator. 2563** 2564** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 2565** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 2566** string after SQLite has finished with it. ^If the fifth argument is 2567** the special value [SQLITE_STATIC], then SQLite assumes that the 2568** information is in static, unmanaged space and does not need to be freed. 2569** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 2570** SQLite makes its own private copy of the data immediately, before 2571** the sqlite3_bind_*() routine returns. 2572** 2573** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 2574** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 2575** (just an integer to hold its size) while it is being processed. 2576** Zeroblobs are intended to serve as placeholders for BLOBs whose 2577** content is later written using 2578** [sqlite3_blob_open | incremental BLOB I/O] routines. 2579** ^A negative value for the zeroblob results in a zero-length BLOB. 2580** 2581** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 2582** for the [prepared statement] or with a prepared statement for which 2583** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 2584** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 2585** routine is passed a [prepared statement] that has been finalized, the 2586** result is undefined and probably harmful. 2587** 2588** ^Bindings are not cleared by the [sqlite3_reset()] routine. 2589** ^Unbound parameters are interpreted as NULL. 2590** 2591** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 2592** [error code] if anything goes wrong. 2593** ^[SQLITE_RANGE] is returned if the parameter 2594** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 2595** 2596** See also: [sqlite3_bind_parameter_count()], 2597** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 2598*/ 2599SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 2600SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double); 2601SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int); 2602SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 2603SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int); 2604SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 2605SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 2606SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 2607SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 2608 2609/* 2610** CAPI3REF: Number Of SQL Parameters 2611** 2612** ^This routine can be used to find the number of [SQL parameters] 2613** in a [prepared statement]. SQL parameters are tokens of the 2614** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 2615** placeholders for values that are [sqlite3_bind_blob | bound] 2616** to the parameters at a later time. 2617** 2618** ^(This routine actually returns the index of the largest (rightmost) 2619** parameter. For all forms except ?NNN, this will correspond to the 2620** number of unique parameters. If parameters of the ?NNN form are used, 2621** there may be gaps in the list.)^ 2622** 2623** See also: [sqlite3_bind_blob|sqlite3_bind()], 2624** [sqlite3_bind_parameter_name()], and 2625** [sqlite3_bind_parameter_index()]. 2626*/ 2627SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*); 2628 2629/* 2630** CAPI3REF: Name Of A Host Parameter 2631** 2632** ^The sqlite3_bind_parameter_name(P,N) interface returns 2633** the name of the N-th [SQL parameter] in the [prepared statement] P. 2634** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 2635** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 2636** respectively. 2637** In other words, the initial ":" or "$" or "@" or "?" 2638** is included as part of the name.)^ 2639** ^Parameters of the form "?" without a following integer have no name 2640** and are referred to as "nameless" or "anonymous parameters". 2641** 2642** ^The first host parameter has an index of 1, not 0. 2643** 2644** ^If the value N is out of range or if the N-th parameter is 2645** nameless, then NULL is returned. ^The returned string is 2646** always in UTF-8 encoding even if the named parameter was 2647** originally specified as UTF-16 in [sqlite3_prepare16()] or 2648** [sqlite3_prepare16_v2()]. 2649** 2650** See also: [sqlite3_bind_blob|sqlite3_bind()], 2651** [sqlite3_bind_parameter_count()], and 2652** [sqlite3_bind_parameter_index()]. 2653*/ 2654SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 2655 2656/* 2657** CAPI3REF: Index Of A Parameter With A Given Name 2658** 2659** ^Return the index of an SQL parameter given its name. ^The 2660** index value returned is suitable for use as the second 2661** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 2662** is returned if no matching parameter is found. ^The parameter 2663** name must be given in UTF-8 even if the original statement 2664** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 2665** 2666** See also: [sqlite3_bind_blob|sqlite3_bind()], 2667** [sqlite3_bind_parameter_count()], and 2668** [sqlite3_bind_parameter_index()]. 2669*/ 2670SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 2671 2672/* 2673** CAPI3REF: Reset All Bindings On A Prepared Statement 2674** 2675** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 2676** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 2677** ^Use this routine to reset all host parameters to NULL. 2678*/ 2679SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*); 2680 2681/* 2682** CAPI3REF: Number Of Columns In A Result Set 2683** 2684** ^Return the number of columns in the result set returned by the 2685** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 2686** statement that does not return data (for example an [UPDATE]). 2687*/ 2688SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt); 2689 2690/* 2691** CAPI3REF: Column Names In A Result Set 2692** 2693** ^These routines return the name assigned to a particular column 2694** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 2695** interface returns a pointer to a zero-terminated UTF-8 string 2696** and sqlite3_column_name16() returns a pointer to a zero-terminated 2697** UTF-16 string. ^The first parameter is the [prepared statement] 2698** that implements the [SELECT] statement. ^The second parameter is the 2699** column number. ^The leftmost column is number 0. 2700** 2701** ^The returned string pointer is valid until either the [prepared statement] 2702** is destroyed by [sqlite3_finalize()] or until the next call to 2703** sqlite3_column_name() or sqlite3_column_name16() on the same column. 2704** 2705** ^If sqlite3_malloc() fails during the processing of either routine 2706** (for example during a conversion from UTF-8 to UTF-16) then a 2707** NULL pointer is returned. 2708** 2709** ^The name of a result column is the value of the "AS" clause for 2710** that column, if there is an AS clause. If there is no AS clause 2711** then the name of the column is unspecified and may change from 2712** one release of SQLite to the next. 2713*/ 2714SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N); 2715SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N); 2716 2717/* 2718** CAPI3REF: Source Of Data In A Query Result 2719** 2720** ^These routines provide a means to determine the database, table, and 2721** table column that is the origin of a particular result column in 2722** [SELECT] statement. 2723** ^The name of the database or table or column can be returned as 2724** either a UTF-8 or UTF-16 string. ^The _database_ routines return 2725** the database name, the _table_ routines return the table name, and 2726** the origin_ routines return the column name. 2727** ^The returned string is valid until the [prepared statement] is destroyed 2728** using [sqlite3_finalize()] or until the same information is requested 2729** again in a different encoding. 2730** 2731** ^The names returned are the original un-aliased names of the 2732** database, table, and column. 2733** 2734** ^The first argument to these interfaces is a [prepared statement]. 2735** ^These functions return information about the Nth result column returned by 2736** the statement, where N is the second function argument. 2737** ^The left-most column is column 0 for these routines. 2738** 2739** ^If the Nth column returned by the statement is an expression or 2740** subquery and is not a column value, then all of these functions return 2741** NULL. ^These routine might also return NULL if a memory allocation error 2742** occurs. ^Otherwise, they return the name of the attached database, table, 2743** or column that query result column was extracted from. 2744** 2745** ^As with all other SQLite APIs, those whose names end with "16" return 2746** UTF-16 encoded strings and the other functions return UTF-8. 2747** 2748** ^These APIs are only available if the library was compiled with the 2749** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 2750** 2751** If two or more threads call one or more of these routines against the same 2752** prepared statement and column at the same time then the results are 2753** undefined. 2754** 2755** If two or more threads call one or more 2756** [sqlite3_column_database_name | column metadata interfaces] 2757** for the same [prepared statement] and result column 2758** at the same time then the results are undefined. 2759*/ 2760SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int); 2761SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 2762SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int); 2763SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 2764SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 2765SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 2766 2767/* 2768** CAPI3REF: Declared Datatype Of A Query Result 2769** 2770** ^(The first parameter is a [prepared statement]. 2771** If this statement is a [SELECT] statement and the Nth column of the 2772** returned result set of that [SELECT] is a table column (not an 2773** expression or subquery) then the declared type of the table 2774** column is returned.)^ ^If the Nth column of the result set is an 2775** expression or subquery, then a NULL pointer is returned. 2776** ^The returned string is always UTF-8 encoded. 2777** 2778** ^(For example, given the database schema: 2779** 2780** CREATE TABLE t1(c1 VARIANT); 2781** 2782** and the following statement to be compiled: 2783** 2784** SELECT c1 + 1, c1 FROM t1; 2785** 2786** this routine would return the string "VARIANT" for the second result 2787** column (i==1), and a NULL pointer for the first result column (i==0).)^ 2788** 2789** ^SQLite uses dynamic run-time typing. ^So just because a column 2790** is declared to contain a particular type does not mean that the 2791** data stored in that column is of the declared type. SQLite is 2792** strongly typed, but the typing is dynamic not static. ^Type 2793** is associated with individual values, not with the containers 2794** used to hold those values. 2795*/ 2796SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int); 2797SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 2798 2799/* 2800** CAPI3REF: Evaluate An SQL Statement 2801** 2802** After a [prepared statement] has been prepared using either 2803** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 2804** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 2805** must be called one or more times to evaluate the statement. 2806** 2807** The details of the behavior of the sqlite3_step() interface depend 2808** on whether the statement was prepared using the newer "v2" interface 2809** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 2810** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 2811** new "v2" interface is recommended for new applications but the legacy 2812** interface will continue to be supported. 2813** 2814** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 2815** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 2816** ^With the "v2" interface, any of the other [result codes] or 2817** [extended result codes] might be returned as well. 2818** 2819** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 2820** database locks it needs to do its job. ^If the statement is a [COMMIT] 2821** or occurs outside of an explicit transaction, then you can retry the 2822** statement. If the statement is not a [COMMIT] and occurs within a 2823** explicit transaction then you should rollback the transaction before 2824** continuing. 2825** 2826** ^[SQLITE_DONE] means that the statement has finished executing 2827** successfully. sqlite3_step() should not be called again on this virtual 2828** machine without first calling [sqlite3_reset()] to reset the virtual 2829** machine back to its initial state. 2830** 2831** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 2832** is returned each time a new row of data is ready for processing by the 2833** caller. The values may be accessed using the [column access functions]. 2834** sqlite3_step() is called again to retrieve the next row of data. 2835** 2836** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 2837** violation) has occurred. sqlite3_step() should not be called again on 2838** the VM. More information may be found by calling [sqlite3_errmsg()]. 2839** ^With the legacy interface, a more specific error code (for example, 2840** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 2841** can be obtained by calling [sqlite3_reset()] on the 2842** [prepared statement]. ^In the "v2" interface, 2843** the more specific error code is returned directly by sqlite3_step(). 2844** 2845** [SQLITE_MISUSE] means that the this routine was called inappropriately. 2846** Perhaps it was called on a [prepared statement] that has 2847** already been [sqlite3_finalize | finalized] or on one that had 2848** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 2849** be the case that the same database connection is being used by two or 2850** more threads at the same moment in time. 2851** 2852** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 2853** API always returns a generic error code, [SQLITE_ERROR], following any 2854** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 2855** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 2856** specific [error codes] that better describes the error. 2857** We admit that this is a goofy design. The problem has been fixed 2858** with the "v2" interface. If you prepare all of your SQL statements 2859** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 2860** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 2861** then the more specific [error codes] are returned directly 2862** by sqlite3_step(). The use of the "v2" interface is recommended. 2863*/ 2864SQLITE_API int sqlite3_step(sqlite3_stmt*); 2865 2866/* 2867** CAPI3REF: Number of columns in a result set 2868** 2869** ^The sqlite3_data_count(P) the number of columns in the 2870** of the result set of [prepared statement] P. 2871*/ 2872SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt); 2873 2874/* 2875** CAPI3REF: Fundamental Datatypes 2876** KEYWORDS: SQLITE_TEXT 2877** 2878** ^(Every value in SQLite has one of five fundamental datatypes: 2879** 2880** <ul> 2881** <li> 64-bit signed integer 2882** <li> 64-bit IEEE floating point number 2883** <li> string 2884** <li> BLOB 2885** <li> NULL 2886** </ul>)^ 2887** 2888** These constants are codes for each of those types. 2889** 2890** Note that the SQLITE_TEXT constant was also used in SQLite version 2 2891** for a completely different meaning. Software that links against both 2892** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 2893** SQLITE_TEXT. 2894*/ 2895#define SQLITE_INTEGER 1 2896#define SQLITE_FLOAT 2 2897#define SQLITE_BLOB 4 2898#define SQLITE_NULL 5 2899#ifdef SQLITE_TEXT 2900# undef SQLITE_TEXT 2901#else 2902# define SQLITE_TEXT 3 2903#endif 2904#define SQLITE3_TEXT 3 2905 2906/* 2907** CAPI3REF: Result Values From A Query 2908** KEYWORDS: {column access functions} 2909** 2910** These routines form the "result set" interface. 2911** 2912** ^These routines return information about a single column of the current 2913** result row of a query. ^In every case the first argument is a pointer 2914** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 2915** that was returned from [sqlite3_prepare_v2()] or one of its variants) 2916** and the second argument is the index of the column for which information 2917** should be returned. ^The leftmost column of the result set has the index 0. 2918** ^The number of columns in the result can be determined using 2919** [sqlite3_column_count()]. 2920** 2921** If the SQL statement does not currently point to a valid row, or if the 2922** column index is out of range, the result is undefined. 2923** These routines may only be called when the most recent call to 2924** [sqlite3_step()] has returned [SQLITE_ROW] and neither 2925** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 2926** If any of these routines are called after [sqlite3_reset()] or 2927** [sqlite3_finalize()] or after [sqlite3_step()] has returned 2928** something other than [SQLITE_ROW], the results are undefined. 2929** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 2930** are called from a different thread while any of these routines 2931** are pending, then the results are undefined. 2932** 2933** ^The sqlite3_column_type() routine returns the 2934** [SQLITE_INTEGER | datatype code] for the initial data type 2935** of the result column. ^The returned value is one of [SQLITE_INTEGER], 2936** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 2937** returned by sqlite3_column_type() is only meaningful if no type 2938** conversions have occurred as described below. After a type conversion, 2939** the value returned by sqlite3_column_type() is undefined. Future 2940** versions of SQLite may change the behavior of sqlite3_column_type() 2941** following a type conversion. 2942** 2943** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 2944** routine returns the number of bytes in that BLOB or string. 2945** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 2946** the string to UTF-8 and then returns the number of bytes. 2947** ^If the result is a numeric value then sqlite3_column_bytes() uses 2948** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 2949** the number of bytes in that string. 2950** ^The value returned does not include the zero terminator at the end 2951** of the string. ^For clarity: the value returned is the number of 2952** bytes in the string, not the number of characters. 2953** 2954** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 2955** even empty strings, are always zero terminated. ^The return 2956** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary 2957** pointer, possibly even a NULL pointer. 2958** 2959** ^The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes() 2960** but leaves the result in UTF-16 in native byte order instead of UTF-8. 2961** ^The zero terminator is not included in this count. 2962** 2963** ^The object returned by [sqlite3_column_value()] is an 2964** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 2965** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 2966** If the [unprotected sqlite3_value] object returned by 2967** [sqlite3_column_value()] is used in any other way, including calls 2968** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 2969** or [sqlite3_value_bytes()], then the behavior is undefined. 2970** 2971** These routines attempt to convert the value where appropriate. ^For 2972** example, if the internal representation is FLOAT and a text result 2973** is requested, [sqlite3_snprintf()] is used internally to perform the 2974** conversion automatically. ^(The following table details the conversions 2975** that are applied: 2976** 2977** <blockquote> 2978** <table border="1"> 2979** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 2980** 2981** <tr><td> NULL <td> INTEGER <td> Result is 0 2982** <tr><td> NULL <td> FLOAT <td> Result is 0.0 2983** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 2984** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 2985** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 2986** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 2987** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 2988** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 2989** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 2990** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 2991** <tr><td> TEXT <td> INTEGER <td> Use atoi() 2992** <tr><td> TEXT <td> FLOAT <td> Use atof() 2993** <tr><td> TEXT <td> BLOB <td> No change 2994** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 2995** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 2996** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 2997** </table> 2998** </blockquote>)^ 2999** 3000** The table above makes reference to standard C library functions atoi() 3001** and atof(). SQLite does not really use these functions. It has its 3002** own equivalent internal routines. The atoi() and atof() names are 3003** used in the table for brevity and because they are familiar to most 3004** C programmers. 3005** 3006** ^Note that when type conversions occur, pointers returned by prior 3007** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3008** sqlite3_column_text16() may be invalidated. 3009** ^(Type conversions and pointer invalidations might occur 3010** in the following cases: 3011** 3012** <ul> 3013** <li> The initial content is a BLOB and sqlite3_column_text() or 3014** sqlite3_column_text16() is called. A zero-terminator might 3015** need to be added to the string.</li> 3016** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3017** sqlite3_column_text16() is called. The content must be converted 3018** to UTF-16.</li> 3019** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3020** sqlite3_column_text() is called. The content must be converted 3021** to UTF-8.</li> 3022** </ul>)^ 3023** 3024** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3025** not invalidate a prior pointer, though of course the content of the buffer 3026** that the prior pointer points to will have been modified. Other kinds 3027** of conversion are done in place when it is possible, but sometimes they 3028** are not possible and in those cases prior pointers are invalidated. 3029** 3030** ^(The safest and easiest to remember policy is to invoke these routines 3031** in one of the following ways: 3032** 3033** <ul> 3034** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3035** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3036** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3037** </ul>)^ 3038** 3039** In other words, you should call sqlite3_column_text(), 3040** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3041** into the desired format, then invoke sqlite3_column_bytes() or 3042** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3043** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3044** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3045** with calls to sqlite3_column_bytes(). 3046** 3047** ^The pointers returned are valid until a type conversion occurs as 3048** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3049** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3050** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3051** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3052** [sqlite3_free()]. 3053** 3054** ^(If a memory allocation error occurs during the evaluation of any 3055** of these routines, a default value is returned. The default value 3056** is either the integer 0, the floating point number 0.0, or a NULL 3057** pointer. Subsequent calls to [sqlite3_errcode()] will return 3058** [SQLITE_NOMEM].)^ 3059*/ 3060SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3061SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3062SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3063SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol); 3064SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol); 3065SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3066SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3067SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3068SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol); 3069SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3070 3071/* 3072** CAPI3REF: Destroy A Prepared Statement Object 3073** 3074** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3075** ^If the statement was executed successfully or not executed at all, then 3076** SQLITE_OK is returned. ^If execution of the statement failed then an 3077** [error code] or [extended error code] is returned. 3078** 3079** ^This routine can be called at any point during the execution of the 3080** [prepared statement]. ^If the virtual machine has not 3081** completed execution when this routine is called, that is like 3082** encountering an error or an [sqlite3_interrupt | interrupt]. 3083** ^Incomplete updates may be rolled back and transactions canceled, 3084** depending on the circumstances, and the 3085** [error code] returned will be [SQLITE_ABORT]. 3086*/ 3087SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt); 3088 3089/* 3090** CAPI3REF: Reset A Prepared Statement Object 3091** 3092** The sqlite3_reset() function is called to reset a [prepared statement] 3093** object back to its initial state, ready to be re-executed. 3094** ^Any SQL statement variables that had values bound to them using 3095** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3096** Use [sqlite3_clear_bindings()] to reset the bindings. 3097** 3098** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3099** back to the beginning of its program. 3100** 3101** ^If the most recent call to [sqlite3_step(S)] for the 3102** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3103** or if [sqlite3_step(S)] has never before been called on S, 3104** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3105** 3106** ^If the most recent call to [sqlite3_step(S)] for the 3107** [prepared statement] S indicated an error, then 3108** [sqlite3_reset(S)] returns an appropriate [error code]. 3109** 3110** ^The [sqlite3_reset(S)] interface does not change the values 3111** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3112*/ 3113SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt); 3114 3115/* 3116** CAPI3REF: Create Or Redefine SQL Functions 3117** KEYWORDS: {function creation routines} 3118** KEYWORDS: {application-defined SQL function} 3119** KEYWORDS: {application-defined SQL functions} 3120** 3121** ^These two functions (collectively known as "function creation routines") 3122** are used to add SQL functions or aggregates or to redefine the behavior 3123** of existing SQL functions or aggregates. The only difference between the 3124** two is that the second parameter, the name of the (scalar) function or 3125** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16 3126** for sqlite3_create_function16(). 3127** 3128** ^The first parameter is the [database connection] to which the SQL 3129** function is to be added. ^If an application uses more than one database 3130** connection then application-defined SQL functions must be added 3131** to each database connection separately. 3132** 3133** The second parameter is the name of the SQL function to be created or 3134** redefined. ^The length of the name is limited to 255 bytes, exclusive of 3135** the zero-terminator. Note that the name length limit is in bytes, not 3136** characters. ^Any attempt to create a function with a longer name 3137** will result in [SQLITE_ERROR] being returned. 3138** 3139** ^The third parameter (nArg) 3140** is the number of arguments that the SQL function or 3141** aggregate takes. ^If this parameter is -1, then the SQL function or 3142** aggregate may take any number of arguments between 0 and the limit 3143** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3144** parameter is less than -1 or greater than 127 then the behavior is 3145** undefined. 3146** 3147** The fourth parameter, eTextRep, specifies what 3148** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3149** its parameters. Any SQL function implementation should be able to work 3150** work with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3151** more efficient with one encoding than another. ^An application may 3152** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3153** times with the same function but with different values of eTextRep. 3154** ^When multiple implementations of the same function are available, SQLite 3155** will pick the one that involves the least amount of data conversion. 3156** If there is only a single implementation which does not care what text 3157** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3158** 3159** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3160** function can gain access to this pointer using [sqlite3_user_data()].)^ 3161** 3162** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are 3163** pointers to C-language functions that implement the SQL function or 3164** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3165** callback only; NULL pointers should be passed as the xStep and xFinal 3166** parameters. ^An aggregate SQL function requires an implementation of xStep 3167** and xFinal and NULL should be passed for xFunc. ^To delete an existing 3168** SQL function or aggregate, pass NULL for all three function callbacks. 3169** 3170** ^It is permitted to register multiple implementations of the same 3171** functions with the same name but with either differing numbers of 3172** arguments or differing preferred text encodings. ^SQLite will use 3173** the implementation that most closely matches the way in which the 3174** SQL function is used. ^A function implementation with a non-negative 3175** nArg parameter is a better match than a function implementation with 3176** a negative nArg. ^A function where the preferred text encoding 3177** matches the database encoding is a better 3178** match than a function where the encoding is different. 3179** ^A function where the encoding difference is between UTF16le and UTF16be 3180** is a closer match than a function where the encoding difference is 3181** between UTF8 and UTF16. 3182** 3183** ^Built-in functions may be overloaded by new application-defined functions. 3184** ^The first application-defined function with a given name overrides all 3185** built-in functions in the same [database connection] with the same name. 3186** ^Subsequent application-defined functions of the same name only override 3187** prior application-defined functions that are an exact match for the 3188** number of parameters and preferred encoding. 3189** 3190** ^An application-defined function is permitted to call other 3191** SQLite interfaces. However, such calls must not 3192** close the database connection nor finalize or reset the prepared 3193** statement in which the function is running. 3194*/ 3195SQLITE_API int sqlite3_create_function( 3196 sqlite3 *db, 3197 const char *zFunctionName, 3198 int nArg, 3199 int eTextRep, 3200 void *pApp, 3201 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3202 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3203 void (*xFinal)(sqlite3_context*) 3204); 3205SQLITE_API int sqlite3_create_function16( 3206 sqlite3 *db, 3207 const void *zFunctionName, 3208 int nArg, 3209 int eTextRep, 3210 void *pApp, 3211 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3212 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3213 void (*xFinal)(sqlite3_context*) 3214); 3215 3216/* 3217** CAPI3REF: Text Encodings 3218** 3219** These constant define integer codes that represent the various 3220** text encodings supported by SQLite. 3221*/ 3222#define SQLITE_UTF8 1 3223#define SQLITE_UTF16LE 2 3224#define SQLITE_UTF16BE 3 3225#define SQLITE_UTF16 4 /* Use native byte order */ 3226#define SQLITE_ANY 5 /* sqlite3_create_function only */ 3227#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3228 3229/* 3230** CAPI3REF: Deprecated Functions 3231** DEPRECATED 3232** 3233** These functions are [deprecated]. In order to maintain 3234** backwards compatibility with older code, these functions continue 3235** to be supported. However, new applications should avoid 3236** the use of these functions. To help encourage people to avoid 3237** using these functions, we are not going to tell you what they do. 3238*/ 3239#ifndef SQLITE_OMIT_DEPRECATED 3240SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3241SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3242SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3243SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void); 3244SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3245SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3246#endif 3247 3248/* 3249** CAPI3REF: Obtaining SQL Function Parameter Values 3250** 3251** The C-language implementation of SQL functions and aggregates uses 3252** this set of interface routines to access the parameter values on 3253** the function or aggregate. 3254** 3255** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3256** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3257** define callbacks that implement the SQL functions and aggregates. 3258** The 4th parameter to these callbacks is an array of pointers to 3259** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3260** each parameter to the SQL function. These routines are used to 3261** extract values from the [sqlite3_value] objects. 3262** 3263** These routines work only with [protected sqlite3_value] objects. 3264** Any attempt to use these routines on an [unprotected sqlite3_value] 3265** object results in undefined behavior. 3266** 3267** ^These routines work just like the corresponding [column access functions] 3268** except that these routines take a single [protected sqlite3_value] object 3269** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3270** 3271** ^The sqlite3_value_text16() interface extracts a UTF-16 string 3272** in the native byte-order of the host machine. ^The 3273** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3274** extract UTF-16 strings as big-endian and little-endian respectively. 3275** 3276** ^(The sqlite3_value_numeric_type() interface attempts to apply 3277** numeric affinity to the value. This means that an attempt is 3278** made to convert the value to an integer or floating point. If 3279** such a conversion is possible without loss of information (in other 3280** words, if the value is a string that looks like a number) 3281** then the conversion is performed. Otherwise no conversion occurs. 3282** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 3283** 3284** Please pay particular attention to the fact that the pointer returned 3285** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3286** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3287** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3288** or [sqlite3_value_text16()]. 3289** 3290** These routines must be called from the same thread as 3291** the SQL function that supplied the [sqlite3_value*] parameters. 3292*/ 3293SQLITE_API const void *sqlite3_value_blob(sqlite3_value*); 3294SQLITE_API int sqlite3_value_bytes(sqlite3_value*); 3295SQLITE_API int sqlite3_value_bytes16(sqlite3_value*); 3296SQLITE_API double sqlite3_value_double(sqlite3_value*); 3297SQLITE_API int sqlite3_value_int(sqlite3_value*); 3298SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3299SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*); 3300SQLITE_API const void *sqlite3_value_text16(sqlite3_value*); 3301SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*); 3302SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*); 3303SQLITE_API int sqlite3_value_type(sqlite3_value*); 3304SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*); 3305 3306/* 3307** CAPI3REF: Obtain Aggregate Function Context 3308** 3309** Implementions of aggregate SQL functions use this 3310** routine to allocate memory for storing their state. 3311** 3312** ^The first time the sqlite3_aggregate_context(C,N) routine is called 3313** for a particular aggregate function, SQLite 3314** allocates N of memory, zeroes out that memory, and returns a pointer 3315** to the new memory. ^On second and subsequent calls to 3316** sqlite3_aggregate_context() for the same aggregate function instance, 3317** the same buffer is returned. Sqlite3_aggregate_context() is normally 3318** called once for each invocation of the xStep callback and then one 3319** last time when the xFinal callback is invoked. ^(When no rows match 3320** an aggregate query, the xStep() callback of the aggregate function 3321** implementation is never called and xFinal() is called exactly once. 3322** In those cases, sqlite3_aggregate_context() might be called for the 3323** first time from within xFinal().)^ 3324** 3325** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is 3326** less than or equal to zero or if a memory allocate error occurs. 3327** 3328** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 3329** determined by the N parameter on first successful call. Changing the 3330** value of N in subsequent call to sqlite3_aggregate_context() within 3331** the same aggregate function instance will not resize the memory 3332** allocation.)^ 3333** 3334** ^SQLite automatically frees the memory allocated by 3335** sqlite3_aggregate_context() when the aggregate query concludes. 3336** 3337** The first parameter must be a copy of the 3338** [sqlite3_context | SQL function context] that is the first parameter 3339** to the xStep or xFinal callback routine that implements the aggregate 3340** function. 3341** 3342** This routine must be called from the same thread in which 3343** the aggregate SQL function is running. 3344*/ 3345SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 3346 3347/* 3348** CAPI3REF: User Data For Functions 3349** 3350** ^The sqlite3_user_data() interface returns a copy of 3351** the pointer that was the pUserData parameter (the 5th parameter) 3352** of the [sqlite3_create_function()] 3353** and [sqlite3_create_function16()] routines that originally 3354** registered the application defined function. 3355** 3356** This routine must be called from the same thread in which 3357** the application-defined function is running. 3358*/ 3359SQLITE_API void *sqlite3_user_data(sqlite3_context*); 3360 3361/* 3362** CAPI3REF: Database Connection For Functions 3363** 3364** ^The sqlite3_context_db_handle() interface returns a copy of 3365** the pointer to the [database connection] (the 1st parameter) 3366** of the [sqlite3_create_function()] 3367** and [sqlite3_create_function16()] routines that originally 3368** registered the application defined function. 3369*/ 3370SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 3371 3372/* 3373** CAPI3REF: Function Auxiliary Data 3374** 3375** The following two functions may be used by scalar SQL functions to 3376** associate metadata with argument values. If the same value is passed to 3377** multiple invocations of the same SQL function during query execution, under 3378** some circumstances the associated metadata may be preserved. This may 3379** be used, for example, to add a regular-expression matching scalar 3380** function. The compiled version of the regular expression is stored as 3381** metadata associated with the SQL value passed as the regular expression 3382** pattern. The compiled regular expression can be reused on multiple 3383** invocations of the same function so that the original pattern string 3384** does not need to be recompiled on each invocation. 3385** 3386** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 3387** associated by the sqlite3_set_auxdata() function with the Nth argument 3388** value to the application-defined function. ^If no metadata has been ever 3389** been set for the Nth argument of the function, or if the corresponding 3390** function parameter has changed since the meta-data was set, 3391** then sqlite3_get_auxdata() returns a NULL pointer. 3392** 3393** ^The sqlite3_set_auxdata() interface saves the metadata 3394** pointed to by its 3rd parameter as the metadata for the N-th 3395** argument of the application-defined function. Subsequent 3396** calls to sqlite3_get_auxdata() might return this data, if it has 3397** not been destroyed. 3398** ^If it is not NULL, SQLite will invoke the destructor 3399** function given by the 4th parameter to sqlite3_set_auxdata() on 3400** the metadata when the corresponding function parameter changes 3401** or when the SQL statement completes, whichever comes first. 3402** 3403** SQLite is free to call the destructor and drop metadata on any 3404** parameter of any function at any time. ^The only guarantee is that 3405** the destructor will be called before the metadata is dropped. 3406** 3407** ^(In practice, metadata is preserved between function calls for 3408** expressions that are constant at compile time. This includes literal 3409** values and [parameters].)^ 3410** 3411** These routines must be called from the same thread in which 3412** the SQL function is running. 3413*/ 3414SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N); 3415SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 3416 3417 3418/* 3419** CAPI3REF: Constants Defining Special Destructor Behavior 3420** 3421** These are special values for the destructor that is passed in as the 3422** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 3423** argument is SQLITE_STATIC, it means that the content pointer is constant 3424** and will never change. It does not need to be destroyed. ^The 3425** SQLITE_TRANSIENT value means that the content will likely change in 3426** the near future and that SQLite should make its own private copy of 3427** the content before returning. 3428** 3429** The typedef is necessary to work around problems in certain 3430** C++ compilers. See ticket #2191. 3431*/ 3432typedef void (*sqlite3_destructor_type)(void*); 3433#define SQLITE_STATIC ((sqlite3_destructor_type)0) 3434#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 3435 3436/* 3437** CAPI3REF: Setting The Result Of An SQL Function 3438** 3439** These routines are used by the xFunc or xFinal callbacks that 3440** implement SQL functions and aggregates. See 3441** [sqlite3_create_function()] and [sqlite3_create_function16()] 3442** for additional information. 3443** 3444** These functions work very much like the [parameter binding] family of 3445** functions used to bind values to host parameters in prepared statements. 3446** Refer to the [SQL parameter] documentation for additional information. 3447** 3448** ^The sqlite3_result_blob() interface sets the result from 3449** an application-defined function to be the BLOB whose content is pointed 3450** to by the second parameter and which is N bytes long where N is the 3451** third parameter. 3452** 3453** ^The sqlite3_result_zeroblob() interfaces set the result of 3454** the application-defined function to be a BLOB containing all zero 3455** bytes and N bytes in size, where N is the value of the 2nd parameter. 3456** 3457** ^The sqlite3_result_double() interface sets the result from 3458** an application-defined function to be a floating point value specified 3459** by its 2nd argument. 3460** 3461** ^The sqlite3_result_error() and sqlite3_result_error16() functions 3462** cause the implemented SQL function to throw an exception. 3463** ^SQLite uses the string pointed to by the 3464** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 3465** as the text of an error message. ^SQLite interprets the error 3466** message string from sqlite3_result_error() as UTF-8. ^SQLite 3467** interprets the string from sqlite3_result_error16() as UTF-16 in native 3468** byte order. ^If the third parameter to sqlite3_result_error() 3469** or sqlite3_result_error16() is negative then SQLite takes as the error 3470** message all text up through the first zero character. 3471** ^If the third parameter to sqlite3_result_error() or 3472** sqlite3_result_error16() is non-negative then SQLite takes that many 3473** bytes (not characters) from the 2nd parameter as the error message. 3474** ^The sqlite3_result_error() and sqlite3_result_error16() 3475** routines make a private copy of the error message text before 3476** they return. Hence, the calling function can deallocate or 3477** modify the text after they return without harm. 3478** ^The sqlite3_result_error_code() function changes the error code 3479** returned by SQLite as a result of an error in a function. ^By default, 3480** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 3481** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 3482** 3483** ^The sqlite3_result_toobig() interface causes SQLite to throw an error 3484** indicating that a string or BLOB is too long to represent. 3485** 3486** ^The sqlite3_result_nomem() interface causes SQLite to throw an error 3487** indicating that a memory allocation failed. 3488** 3489** ^The sqlite3_result_int() interface sets the return value 3490** of the application-defined function to be the 32-bit signed integer 3491** value given in the 2nd argument. 3492** ^The sqlite3_result_int64() interface sets the return value 3493** of the application-defined function to be the 64-bit signed integer 3494** value given in the 2nd argument. 3495** 3496** ^The sqlite3_result_null() interface sets the return value 3497** of the application-defined function to be NULL. 3498** 3499** ^The sqlite3_result_text(), sqlite3_result_text16(), 3500** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 3501** set the return value of the application-defined function to be 3502** a text string which is represented as UTF-8, UTF-16 native byte order, 3503** UTF-16 little endian, or UTF-16 big endian, respectively. 3504** ^SQLite takes the text result from the application from 3505** the 2nd parameter of the sqlite3_result_text* interfaces. 3506** ^If the 3rd parameter to the sqlite3_result_text* interfaces 3507** is negative, then SQLite takes result text from the 2nd parameter 3508** through the first zero character. 3509** ^If the 3rd parameter to the sqlite3_result_text* interfaces 3510** is non-negative, then as many bytes (not characters) of the text 3511** pointed to by the 2nd parameter are taken as the application-defined 3512** function result. 3513** ^If the 4th parameter to the sqlite3_result_text* interfaces 3514** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 3515** function as the destructor on the text or BLOB result when it has 3516** finished using that result. 3517** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 3518** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 3519** assumes that the text or BLOB result is in constant space and does not 3520** copy the content of the parameter nor call a destructor on the content 3521** when it has finished using that result. 3522** ^If the 4th parameter to the sqlite3_result_text* interfaces 3523** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 3524** then SQLite makes a copy of the result into space obtained from 3525** from [sqlite3_malloc()] before it returns. 3526** 3527** ^The sqlite3_result_value() interface sets the result of 3528** the application-defined function to be a copy the 3529** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 3530** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 3531** so that the [sqlite3_value] specified in the parameter may change or 3532** be deallocated after sqlite3_result_value() returns without harm. 3533** ^A [protected sqlite3_value] object may always be used where an 3534** [unprotected sqlite3_value] object is required, so either 3535** kind of [sqlite3_value] object can be used with this interface. 3536** 3537** If these routines are called from within the different thread 3538** than the one containing the application-defined function that received 3539** the [sqlite3_context] pointer, the results are undefined. 3540*/ 3541SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 3542SQLITE_API void sqlite3_result_double(sqlite3_context*, double); 3543SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int); 3544SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int); 3545SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*); 3546SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*); 3547SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int); 3548SQLITE_API void sqlite3_result_int(sqlite3_context*, int); 3549SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 3550SQLITE_API void sqlite3_result_null(sqlite3_context*); 3551SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 3552SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 3553SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 3554SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 3555SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 3556SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n); 3557 3558/* 3559** CAPI3REF: Define New Collating Sequences 3560** 3561** These functions are used to add new collation sequences to the 3562** [database connection] specified as the first argument. 3563** 3564** ^The name of the new collation sequence is specified as a UTF-8 string 3565** for sqlite3_create_collation() and sqlite3_create_collation_v2() 3566** and a UTF-16 string for sqlite3_create_collation16(). ^In all cases 3567** the name is passed as the second function argument. 3568** 3569** ^The third argument may be one of the constants [SQLITE_UTF8], 3570** [SQLITE_UTF16LE], or [SQLITE_UTF16BE], indicating that the user-supplied 3571** routine expects to be passed pointers to strings encoded using UTF-8, 3572** UTF-16 little-endian, or UTF-16 big-endian, respectively. ^The 3573** third argument might also be [SQLITE_UTF16] to indicate that the routine 3574** expects pointers to be UTF-16 strings in the native byte order, or the 3575** argument can be [SQLITE_UTF16_ALIGNED] if the 3576** the routine expects pointers to 16-bit word aligned strings 3577** of UTF-16 in the native byte order. 3578** 3579** A pointer to the user supplied routine must be passed as the fifth 3580** argument. ^If it is NULL, this is the same as deleting the collation 3581** sequence (so that SQLite cannot call it anymore). 3582** ^Each time the application supplied function is invoked, it is passed 3583** as its first parameter a copy of the void* passed as the fourth argument 3584** to sqlite3_create_collation() or sqlite3_create_collation16(). 3585** 3586** ^The remaining arguments to the application-supplied routine are two strings, 3587** each represented by a (length, data) pair and encoded in the encoding 3588** that was passed as the third argument when the collation sequence was 3589** registered. The application defined collation routine should 3590** return negative, zero or positive if the first string is less than, 3591** equal to, or greater than the second string. i.e. (STRING1 - STRING2). 3592** 3593** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 3594** except that it takes an extra argument which is a destructor for 3595** the collation. ^The destructor is called when the collation is 3596** destroyed and is passed a copy of the fourth parameter void* pointer 3597** of the sqlite3_create_collation_v2(). 3598** ^Collations are destroyed when they are overridden by later calls to the 3599** collation creation functions or when the [database connection] is closed 3600** using [sqlite3_close()]. 3601** 3602** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 3603*/ 3604SQLITE_API int sqlite3_create_collation( 3605 sqlite3*, 3606 const char *zName, 3607 int eTextRep, 3608 void*, 3609 int(*xCompare)(void*,int,const void*,int,const void*) 3610); 3611SQLITE_API int sqlite3_create_collation_v2( 3612 sqlite3*, 3613 const char *zName, 3614 int eTextRep, 3615 void*, 3616 int(*xCompare)(void*,int,const void*,int,const void*), 3617 void(*xDestroy)(void*) 3618); 3619SQLITE_API int sqlite3_create_collation16( 3620 sqlite3*, 3621 const void *zName, 3622 int eTextRep, 3623 void*, 3624 int(*xCompare)(void*,int,const void*,int,const void*) 3625); 3626 3627/* 3628** CAPI3REF: Collation Needed Callbacks 3629** 3630** ^To avoid having to register all collation sequences before a database 3631** can be used, a single callback function may be registered with the 3632** [database connection] to be invoked whenever an undefined collation 3633** sequence is required. 3634** 3635** ^If the function is registered using the sqlite3_collation_needed() API, 3636** then it is passed the names of undefined collation sequences as strings 3637** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 3638** the names are passed as UTF-16 in machine native byte order. 3639** ^A call to either function replaces the existing collation-needed callback. 3640** 3641** ^(When the callback is invoked, the first argument passed is a copy 3642** of the second argument to sqlite3_collation_needed() or 3643** sqlite3_collation_needed16(). The second argument is the database 3644** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 3645** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 3646** sequence function required. The fourth parameter is the name of the 3647** required collation sequence.)^ 3648** 3649** The callback function should register the desired collation using 3650** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 3651** [sqlite3_create_collation_v2()]. 3652*/ 3653SQLITE_API int sqlite3_collation_needed( 3654 sqlite3*, 3655 void*, 3656 void(*)(void*,sqlite3*,int eTextRep,const char*) 3657); 3658SQLITE_API int sqlite3_collation_needed16( 3659 sqlite3*, 3660 void*, 3661 void(*)(void*,sqlite3*,int eTextRep,const void*) 3662); 3663 3664/* 3665** Specify the key for an encrypted database. This routine should be 3666** called right after sqlite3_open(). 3667** 3668** The code to implement this API is not available in the public release 3669** of SQLite. 3670*/ 3671SQLITE_API int sqlite3_key( 3672 sqlite3 *db, /* Database to be rekeyed */ 3673 const void *pKey, int nKey /* The key */ 3674); 3675 3676/* 3677** Change the key on an open database. If the current database is not 3678** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 3679** database is decrypted. 3680** 3681** The code to implement this API is not available in the public release 3682** of SQLite. 3683*/ 3684SQLITE_API int sqlite3_rekey( 3685 sqlite3 *db, /* Database to be rekeyed */ 3686 const void *pKey, int nKey /* The new key */ 3687); 3688 3689/* 3690** CAPI3REF: Suspend Execution For A Short Time 3691** 3692** ^The sqlite3_sleep() function causes the current thread to suspend execution 3693** for at least a number of milliseconds specified in its parameter. 3694** 3695** ^If the operating system does not support sleep requests with 3696** millisecond time resolution, then the time will be rounded up to 3697** the nearest second. ^The number of milliseconds of sleep actually 3698** requested from the operating system is returned. 3699** 3700** ^SQLite implements this interface by calling the xSleep() 3701** method of the default [sqlite3_vfs] object. 3702*/ 3703SQLITE_API int sqlite3_sleep(int); 3704 3705/* 3706** CAPI3REF: Name Of The Folder Holding Temporary Files 3707** 3708** ^(If this global variable is made to point to a string which is 3709** the name of a folder (a.k.a. directory), then all temporary files 3710** created by SQLite when using a built-in [sqlite3_vfs | VFS] 3711** will be placed in that directory.)^ ^If this variable 3712** is a NULL pointer, then SQLite performs a search for an appropriate 3713** temporary file directory. 3714** 3715** It is not safe to read or modify this variable in more than one 3716** thread at a time. It is not safe to read or modify this variable 3717** if a [database connection] is being used at the same time in a separate 3718** thread. 3719** It is intended that this variable be set once 3720** as part of process initialization and before any SQLite interface 3721** routines have been called and that this variable remain unchanged 3722** thereafter. 3723** 3724** ^The [temp_store_directory pragma] may modify this variable and cause 3725** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 3726** the [temp_store_directory pragma] always assumes that any string 3727** that this variable points to is held in memory obtained from 3728** [sqlite3_malloc] and the pragma may attempt to free that memory 3729** using [sqlite3_free]. 3730** Hence, if this variable is modified directly, either it should be 3731** made NULL or made to point to memory obtained from [sqlite3_malloc] 3732** or else the use of the [temp_store_directory pragma] should be avoided. 3733*/ 3734SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory; 3735 3736/* 3737** CAPI3REF: Test For Auto-Commit Mode 3738** KEYWORDS: {autocommit mode} 3739** 3740** ^The sqlite3_get_autocommit() interface returns non-zero or 3741** zero if the given database connection is or is not in autocommit mode, 3742** respectively. ^Autocommit mode is on by default. 3743** ^Autocommit mode is disabled by a [BEGIN] statement. 3744** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 3745** 3746** If certain kinds of errors occur on a statement within a multi-statement 3747** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 3748** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 3749** transaction might be rolled back automatically. The only way to 3750** find out whether SQLite automatically rolled back the transaction after 3751** an error is to use this function. 3752** 3753** If another thread changes the autocommit status of the database 3754** connection while this routine is running, then the return value 3755** is undefined. 3756*/ 3757SQLITE_API int sqlite3_get_autocommit(sqlite3*); 3758 3759/* 3760** CAPI3REF: Find The Database Handle Of A Prepared Statement 3761** 3762** ^The sqlite3_db_handle interface returns the [database connection] handle 3763** to which a [prepared statement] belongs. ^The [database connection] 3764** returned by sqlite3_db_handle is the same [database connection] 3765** that was the first argument 3766** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 3767** create the statement in the first place. 3768*/ 3769SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 3770 3771/* 3772** CAPI3REF: Find the next prepared statement 3773** 3774** ^This interface returns a pointer to the next [prepared statement] after 3775** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 3776** then this interface returns a pointer to the first prepared statement 3777** associated with the database connection pDb. ^If no prepared statement 3778** satisfies the conditions of this routine, it returns NULL. 3779** 3780** The [database connection] pointer D in a call to 3781** [sqlite3_next_stmt(D,S)] must refer to an open database 3782** connection and in particular must not be a NULL pointer. 3783*/ 3784SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 3785 3786/* 3787** CAPI3REF: Commit And Rollback Notification Callbacks 3788** 3789** ^The sqlite3_commit_hook() interface registers a callback 3790** function to be invoked whenever a transaction is [COMMIT | committed]. 3791** ^Any callback set by a previous call to sqlite3_commit_hook() 3792** for the same database connection is overridden. 3793** ^The sqlite3_rollback_hook() interface registers a callback 3794** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 3795** ^Any callback set by a previous call to sqlite3_rollback_hook() 3796** for the same database connection is overridden. 3797** ^The pArg argument is passed through to the callback. 3798** ^If the callback on a commit hook function returns non-zero, 3799** then the commit is converted into a rollback. 3800** 3801** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 3802** return the P argument from the previous call of the same function 3803** on the same [database connection] D, or NULL for 3804** the first call for each function on D. 3805** 3806** The callback implementation must not do anything that will modify 3807** the database connection that invoked the callback. Any actions 3808** to modify the database connection must be deferred until after the 3809** completion of the [sqlite3_step()] call that triggered the commit 3810** or rollback hook in the first place. 3811** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3812** database connections for the meaning of "modify" in this paragraph. 3813** 3814** ^Registering a NULL function disables the callback. 3815** 3816** ^When the commit hook callback routine returns zero, the [COMMIT] 3817** operation is allowed to continue normally. ^If the commit hook 3818** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 3819** ^The rollback hook is invoked on a rollback that results from a commit 3820** hook returning non-zero, just as it would be with any other rollback. 3821** 3822** ^For the purposes of this API, a transaction is said to have been 3823** rolled back if an explicit "ROLLBACK" statement is executed, or 3824** an error or constraint causes an implicit rollback to occur. 3825** ^The rollback callback is not invoked if a transaction is 3826** automatically rolled back because the database connection is closed. 3827** ^The rollback callback is not invoked if a transaction is 3828** rolled back because a commit callback returned non-zero. 3829** 3830** See also the [sqlite3_update_hook()] interface. 3831*/ 3832SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 3833SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 3834 3835/* 3836** CAPI3REF: Data Change Notification Callbacks 3837** 3838** ^The sqlite3_update_hook() interface registers a callback function 3839** with the [database connection] identified by the first argument 3840** to be invoked whenever a row is updated, inserted or deleted. 3841** ^Any callback set by a previous call to this function 3842** for the same database connection is overridden. 3843** 3844** ^The second argument is a pointer to the function to invoke when a 3845** row is updated, inserted or deleted. 3846** ^The first argument to the callback is a copy of the third argument 3847** to sqlite3_update_hook(). 3848** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 3849** or [SQLITE_UPDATE], depending on the operation that caused the callback 3850** to be invoked. 3851** ^The third and fourth arguments to the callback contain pointers to the 3852** database and table name containing the affected row. 3853** ^The final callback parameter is the [rowid] of the row. 3854** ^In the case of an update, this is the [rowid] after the update takes place. 3855** 3856** ^(The update hook is not invoked when internal system tables are 3857** modified (i.e. sqlite_master and sqlite_sequence).)^ 3858** 3859** ^In the current implementation, the update hook 3860** is not invoked when duplication rows are deleted because of an 3861** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 3862** invoked when rows are deleted using the [truncate optimization]. 3863** The exceptions defined in this paragraph might change in a future 3864** release of SQLite. 3865** 3866** The update hook implementation must not do anything that will modify 3867** the database connection that invoked the update hook. Any actions 3868** to modify the database connection must be deferred until after the 3869** completion of the [sqlite3_step()] call that triggered the update hook. 3870** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3871** database connections for the meaning of "modify" in this paragraph. 3872** 3873** ^The sqlite3_update_hook(D,C,P) function 3874** returns the P argument from the previous call 3875** on the same [database connection] D, or NULL for 3876** the first call on D. 3877** 3878** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 3879** interfaces. 3880*/ 3881SQLITE_API void *sqlite3_update_hook( 3882 sqlite3*, 3883 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 3884 void* 3885); 3886 3887/* 3888** CAPI3REF: Enable Or Disable Shared Pager Cache 3889** KEYWORDS: {shared cache} 3890** 3891** ^(This routine enables or disables the sharing of the database cache 3892** and schema data structures between [database connection | connections] 3893** to the same database. Sharing is enabled if the argument is true 3894** and disabled if the argument is false.)^ 3895** 3896** ^Cache sharing is enabled and disabled for an entire process. 3897** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 3898** sharing was enabled or disabled for each thread separately. 3899** 3900** ^(The cache sharing mode set by this interface effects all subsequent 3901** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 3902** Existing database connections continue use the sharing mode 3903** that was in effect at the time they were opened.)^ 3904** 3905** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 3906** successfully. An [error code] is returned otherwise.)^ 3907** 3908** ^Shared cache is disabled by default. But this might change in 3909** future releases of SQLite. Applications that care about shared 3910** cache setting should set it explicitly. 3911** 3912** See Also: [SQLite Shared-Cache Mode] 3913*/ 3914SQLITE_API int sqlite3_enable_shared_cache(int); 3915 3916/* 3917** CAPI3REF: Attempt To Free Heap Memory 3918** 3919** ^The sqlite3_release_memory() interface attempts to free N bytes 3920** of heap memory by deallocating non-essential memory allocations 3921** held by the database library. Memory used to cache database 3922** pages to improve performance is an example of non-essential memory. 3923** ^sqlite3_release_memory() returns the number of bytes actually freed, 3924** which might be more or less than the amount requested. 3925*/ 3926SQLITE_API int sqlite3_release_memory(int); 3927 3928/* 3929** CAPI3REF: Impose A Limit On Heap Size 3930** 3931** ^The sqlite3_soft_heap_limit() interface places a "soft" limit 3932** on the amount of heap memory that may be allocated by SQLite. 3933** ^If an internal allocation is requested that would exceed the 3934** soft heap limit, [sqlite3_release_memory()] is invoked one or 3935** more times to free up some space before the allocation is performed. 3936** 3937** ^The limit is called "soft" because if [sqlite3_release_memory()] 3938** cannot free sufficient memory to prevent the limit from being exceeded, 3939** the memory is allocated anyway and the current operation proceeds. 3940** 3941** ^A negative or zero value for N means that there is no soft heap limit and 3942** [sqlite3_release_memory()] will only be called when memory is exhausted. 3943** ^The default value for the soft heap limit is zero. 3944** 3945** ^(SQLite makes a best effort to honor the soft heap limit. 3946** But if the soft heap limit cannot be honored, execution will 3947** continue without error or notification.)^ This is why the limit is 3948** called a "soft" limit. It is advisory only. 3949** 3950** Prior to SQLite version 3.5.0, this routine only constrained the memory 3951** allocated by a single thread - the same thread in which this routine 3952** runs. Beginning with SQLite version 3.5.0, the soft heap limit is 3953** applied to all threads. The value specified for the soft heap limit 3954** is an upper bound on the total memory allocation for all threads. In 3955** version 3.5.0 there is no mechanism for limiting the heap usage for 3956** individual threads. 3957*/ 3958SQLITE_API void sqlite3_soft_heap_limit(int); 3959 3960/* 3961** CAPI3REF: Extract Metadata About A Column Of A Table 3962** 3963** ^This routine returns metadata about a specific column of a specific 3964** database table accessible using the [database connection] handle 3965** passed as the first function argument. 3966** 3967** ^The column is identified by the second, third and fourth parameters to 3968** this function. ^The second parameter is either the name of the database 3969** (i.e. "main", "temp", or an attached database) containing the specified 3970** table or NULL. ^If it is NULL, then all attached databases are searched 3971** for the table using the same algorithm used by the database engine to 3972** resolve unqualified table references. 3973** 3974** ^The third and fourth parameters to this function are the table and column 3975** name of the desired column, respectively. Neither of these parameters 3976** may be NULL. 3977** 3978** ^Metadata is returned by writing to the memory locations passed as the 5th 3979** and subsequent parameters to this function. ^Any of these arguments may be 3980** NULL, in which case the corresponding element of metadata is omitted. 3981** 3982** ^(<blockquote> 3983** <table border="1"> 3984** <tr><th> Parameter <th> Output<br>Type <th> Description 3985** 3986** <tr><td> 5th <td> const char* <td> Data type 3987** <tr><td> 6th <td> const char* <td> Name of default collation sequence 3988** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 3989** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 3990** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 3991** </table> 3992** </blockquote>)^ 3993** 3994** ^The memory pointed to by the character pointers returned for the 3995** declaration type and collation sequence is valid only until the next 3996** call to any SQLite API function. 3997** 3998** ^If the specified table is actually a view, an [error code] is returned. 3999** 4000** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4001** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4002** parameters are set for the explicitly declared column. ^(If there is no 4003** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4004** parameters are set as follows: 4005** 4006** <pre> 4007** data type: "INTEGER" 4008** collation sequence: "BINARY" 4009** not null: 0 4010** primary key: 1 4011** auto increment: 0 4012** </pre>)^ 4013** 4014** ^(This function may load one or more schemas from database files. If an 4015** error occurs during this process, or if the requested table or column 4016** cannot be found, an [error code] is returned and an error message left 4017** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4018** 4019** ^This API is only available if the library was compiled with the 4020** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4021*/ 4022SQLITE_API int sqlite3_table_column_metadata( 4023 sqlite3 *db, /* Connection handle */ 4024 const char *zDbName, /* Database name or NULL */ 4025 const char *zTableName, /* Table name */ 4026 const char *zColumnName, /* Column name */ 4027 char const **pzDataType, /* OUTPUT: Declared data type */ 4028 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4029 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4030 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4031 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4032); 4033 4034/* 4035** CAPI3REF: Load An Extension 4036** 4037** ^This interface loads an SQLite extension library from the named file. 4038** 4039** ^The sqlite3_load_extension() interface attempts to load an 4040** SQLite extension library contained in the file zFile. 4041** 4042** ^The entry point is zProc. 4043** ^zProc may be 0, in which case the name of the entry point 4044** defaults to "sqlite3_extension_init". 4045** ^The sqlite3_load_extension() interface returns 4046** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4047** ^If an error occurs and pzErrMsg is not 0, then the 4048** [sqlite3_load_extension()] interface shall attempt to 4049** fill *pzErrMsg with error message text stored in memory 4050** obtained from [sqlite3_malloc()]. The calling function 4051** should free this memory by calling [sqlite3_free()]. 4052** 4053** ^Extension loading must be enabled using 4054** [sqlite3_enable_load_extension()] prior to calling this API, 4055** otherwise an error will be returned. 4056** 4057** See also the [load_extension() SQL function]. 4058*/ 4059SQLITE_API int sqlite3_load_extension( 4060 sqlite3 *db, /* Load the extension into this database connection */ 4061 const char *zFile, /* Name of the shared library containing extension */ 4062 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4063 char **pzErrMsg /* Put error message here if not 0 */ 4064); 4065 4066/* 4067** CAPI3REF: Enable Or Disable Extension Loading 4068** 4069** ^So as not to open security holes in older applications that are 4070** unprepared to deal with extension loading, and as a means of disabling 4071** extension loading while evaluating user-entered SQL, the following API 4072** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4073** 4074** ^Extension loading is off by default. See ticket #1863. 4075** ^Call the sqlite3_enable_load_extension() routine with onoff==1 4076** to turn extension loading on and call it with onoff==0 to turn 4077** it back off again. 4078*/ 4079SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4080 4081/* 4082** CAPI3REF: Automatically Load An Extensions 4083** 4084** ^This API can be invoked at program startup in order to register 4085** one or more statically linked extensions that will be available 4086** to all new [database connections]. 4087** 4088** ^(This routine stores a pointer to the extension entry point 4089** in an array that is obtained from [sqlite3_malloc()]. That memory 4090** is deallocated by [sqlite3_reset_auto_extension()].)^ 4091** 4092** ^This function registers an extension entry point that is 4093** automatically invoked whenever a new [database connection] 4094** is opened using [sqlite3_open()], [sqlite3_open16()], 4095** or [sqlite3_open_v2()]. 4096** ^Duplicate extensions are detected so calling this routine 4097** multiple times with the same extension is harmless. 4098** ^Automatic extensions apply across all threads. 4099*/ 4100SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4101 4102/* 4103** CAPI3REF: Reset Automatic Extension Loading 4104** 4105** ^(This function disables all previously registered automatic 4106** extensions. It undoes the effect of all prior 4107** [sqlite3_auto_extension()] calls.)^ 4108** 4109** ^This function disables automatic extensions in all threads. 4110*/ 4111SQLITE_API void sqlite3_reset_auto_extension(void); 4112 4113/* 4114****** EXPERIMENTAL - subject to change without notice ************** 4115** 4116** The interface to the virtual-table mechanism is currently considered 4117** to be experimental. The interface might change in incompatible ways. 4118** If this is a problem for you, do not use the interface at this time. 4119** 4120** When the virtual-table mechanism stabilizes, we will declare the 4121** interface fixed, support it indefinitely, and remove this comment. 4122*/ 4123 4124/* 4125** Structures used by the virtual table interface 4126*/ 4127typedef struct sqlite3_vtab sqlite3_vtab; 4128typedef struct sqlite3_index_info sqlite3_index_info; 4129typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4130typedef struct sqlite3_module sqlite3_module; 4131 4132/* 4133** CAPI3REF: Virtual Table Object 4134** KEYWORDS: sqlite3_module {virtual table module} 4135** EXPERIMENTAL 4136** 4137** This structure, sometimes called a a "virtual table module", 4138** defines the implementation of a [virtual tables]. 4139** This structure consists mostly of methods for the module. 4140** 4141** ^A virtual table module is created by filling in a persistent 4142** instance of this structure and passing a pointer to that instance 4143** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4144** ^The registration remains valid until it is replaced by a different 4145** module or until the [database connection] closes. The content 4146** of this structure must not change while it is registered with 4147** any database connection. 4148*/ 4149struct sqlite3_module { 4150 int iVersion; 4151 int (*xCreate)(sqlite3*, void *pAux, 4152 int argc, const char *const*argv, 4153 sqlite3_vtab **ppVTab, char**); 4154 int (*xConnect)(sqlite3*, void *pAux, 4155 int argc, const char *const*argv, 4156 sqlite3_vtab **ppVTab, char**); 4157 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4158 int (*xDisconnect)(sqlite3_vtab *pVTab); 4159 int (*xDestroy)(sqlite3_vtab *pVTab); 4160 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4161 int (*xClose)(sqlite3_vtab_cursor*); 4162 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4163 int argc, sqlite3_value **argv); 4164 int (*xNext)(sqlite3_vtab_cursor*); 4165 int (*xEof)(sqlite3_vtab_cursor*); 4166 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4167 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4168 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4169 int (*xBegin)(sqlite3_vtab *pVTab); 4170 int (*xSync)(sqlite3_vtab *pVTab); 4171 int (*xCommit)(sqlite3_vtab *pVTab); 4172 int (*xRollback)(sqlite3_vtab *pVTab); 4173 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4174 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4175 void **ppArg); 4176 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4177}; 4178 4179/* 4180** CAPI3REF: Virtual Table Indexing Information 4181** KEYWORDS: sqlite3_index_info 4182** EXPERIMENTAL 4183** 4184** The sqlite3_index_info structure and its substructures is used to 4185** pass information into and receive the reply from the [xBestIndex] 4186** method of a [virtual table module]. The fields under **Inputs** are the 4187** inputs to xBestIndex and are read-only. xBestIndex inserts its 4188** results into the **Outputs** fields. 4189** 4190** ^(The aConstraint[] array records WHERE clause constraints of the form: 4191** 4192** <pre>column OP expr</pre> 4193** 4194** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 4195** stored in aConstraint[].op.)^ ^(The index of the column is stored in 4196** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 4197** expr on the right-hand side can be evaluated (and thus the constraint 4198** is usable) and false if it cannot.)^ 4199** 4200** ^The optimizer automatically inverts terms of the form "expr OP column" 4201** and makes other simplifications to the WHERE clause in an attempt to 4202** get as many WHERE clause terms into the form shown above as possible. 4203** ^The aConstraint[] array only reports WHERE clause terms that are 4204** relevant to the particular virtual table being queried. 4205** 4206** ^Information about the ORDER BY clause is stored in aOrderBy[]. 4207** ^Each term of aOrderBy records a column of the ORDER BY clause. 4208** 4209** The [xBestIndex] method must fill aConstraintUsage[] with information 4210** about what parameters to pass to xFilter. ^If argvIndex>0 then 4211** the right-hand side of the corresponding aConstraint[] is evaluated 4212** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 4213** is true, then the constraint is assumed to be fully handled by the 4214** virtual table and is not checked again by SQLite.)^ 4215** 4216** ^The idxNum and idxPtr values are recorded and passed into the 4217** [xFilter] method. 4218** ^[sqlite3_free()] is used to free idxPtr if and only if 4219** needToFreeIdxPtr is true. 4220** 4221** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 4222** the correct order to satisfy the ORDER BY clause so that no separate 4223** sorting step is required. 4224** 4225** ^The estimatedCost value is an estimate of the cost of doing the 4226** particular lookup. A full scan of a table with N entries should have 4227** a cost of N. A binary search of a table of N entries should have a 4228** cost of approximately log(N). 4229*/ 4230struct sqlite3_index_info { 4231 /* Inputs */ 4232 int nConstraint; /* Number of entries in aConstraint */ 4233 struct sqlite3_index_constraint { 4234 int iColumn; /* Column on left-hand side of constraint */ 4235 unsigned char op; /* Constraint operator */ 4236 unsigned char usable; /* True if this constraint is usable */ 4237 int iTermOffset; /* Used internally - xBestIndex should ignore */ 4238 } *aConstraint; /* Table of WHERE clause constraints */ 4239 int nOrderBy; /* Number of terms in the ORDER BY clause */ 4240 struct sqlite3_index_orderby { 4241 int iColumn; /* Column number */ 4242 unsigned char desc; /* True for DESC. False for ASC. */ 4243 } *aOrderBy; /* The ORDER BY clause */ 4244 /* Outputs */ 4245 struct sqlite3_index_constraint_usage { 4246 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 4247 unsigned char omit; /* Do not code a test for this constraint */ 4248 } *aConstraintUsage; 4249 int idxNum; /* Number used to identify the index */ 4250 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 4251 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 4252 int orderByConsumed; /* True if output is already ordered */ 4253 double estimatedCost; /* Estimated cost of using this index */ 4254}; 4255#define SQLITE_INDEX_CONSTRAINT_EQ 2 4256#define SQLITE_INDEX_CONSTRAINT_GT 4 4257#define SQLITE_INDEX_CONSTRAINT_LE 8 4258#define SQLITE_INDEX_CONSTRAINT_LT 16 4259#define SQLITE_INDEX_CONSTRAINT_GE 32 4260#define SQLITE_INDEX_CONSTRAINT_MATCH 64 4261 4262/* 4263** CAPI3REF: Register A Virtual Table Implementation 4264** EXPERIMENTAL 4265** 4266** ^These routines are used to register a new [virtual table module] name. 4267** ^Module names must be registered before 4268** creating a new [virtual table] using the module and before using a 4269** preexisting [virtual table] for the module. 4270** 4271** ^The module name is registered on the [database connection] specified 4272** by the first parameter. ^The name of the module is given by the 4273** second parameter. ^The third parameter is a pointer to 4274** the implementation of the [virtual table module]. ^The fourth 4275** parameter is an arbitrary client data pointer that is passed through 4276** into the [xCreate] and [xConnect] methods of the virtual table module 4277** when a new virtual table is be being created or reinitialized. 4278** 4279** ^The sqlite3_create_module_v2() interface has a fifth parameter which 4280** is a pointer to a destructor for the pClientData. ^SQLite will 4281** invoke the destructor function (if it is not NULL) when SQLite 4282** no longer needs the pClientData pointer. ^The sqlite3_create_module() 4283** interface is equivalent to sqlite3_create_module_v2() with a NULL 4284** destructor. 4285*/ 4286SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_create_module( 4287 sqlite3 *db, /* SQLite connection to register module with */ 4288 const char *zName, /* Name of the module */ 4289 const sqlite3_module *p, /* Methods for the module */ 4290 void *pClientData /* Client data for xCreate/xConnect */ 4291); 4292SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_create_module_v2( 4293 sqlite3 *db, /* SQLite connection to register module with */ 4294 const char *zName, /* Name of the module */ 4295 const sqlite3_module *p, /* Methods for the module */ 4296 void *pClientData, /* Client data for xCreate/xConnect */ 4297 void(*xDestroy)(void*) /* Module destructor function */ 4298); 4299 4300/* 4301** CAPI3REF: Virtual Table Instance Object 4302** KEYWORDS: sqlite3_vtab 4303** EXPERIMENTAL 4304** 4305** Every [virtual table module] implementation uses a subclass 4306** of this object to describe a particular instance 4307** of the [virtual table]. Each subclass will 4308** be tailored to the specific needs of the module implementation. 4309** The purpose of this superclass is to define certain fields that are 4310** common to all module implementations. 4311** 4312** ^Virtual tables methods can set an error message by assigning a 4313** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 4314** take care that any prior string is freed by a call to [sqlite3_free()] 4315** prior to assigning a new string to zErrMsg. ^After the error message 4316** is delivered up to the client application, the string will be automatically 4317** freed by sqlite3_free() and the zErrMsg field will be zeroed. 4318*/ 4319struct sqlite3_vtab { 4320 const sqlite3_module *pModule; /* The module for this virtual table */ 4321 int nRef; /* NO LONGER USED */ 4322 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 4323 /* Virtual table implementations will typically add additional fields */ 4324}; 4325 4326/* 4327** CAPI3REF: Virtual Table Cursor Object 4328** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 4329** EXPERIMENTAL 4330** 4331** Every [virtual table module] implementation uses a subclass of the 4332** following structure to describe cursors that point into the 4333** [virtual table] and are used 4334** to loop through the virtual table. Cursors are created using the 4335** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 4336** by the [sqlite3_module.xClose | xClose] method. Cursors are used 4337** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 4338** of the module. Each module implementation will define 4339** the content of a cursor structure to suit its own needs. 4340** 4341** This superclass exists in order to define fields of the cursor that 4342** are common to all implementations. 4343*/ 4344struct sqlite3_vtab_cursor { 4345 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 4346 /* Virtual table implementations will typically add additional fields */ 4347}; 4348 4349/* 4350** CAPI3REF: Declare The Schema Of A Virtual Table 4351** EXPERIMENTAL 4352** 4353** ^The [xCreate] and [xConnect] methods of a 4354** [virtual table module] call this interface 4355** to declare the format (the names and datatypes of the columns) of 4356** the virtual tables they implement. 4357*/ 4358SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 4359 4360/* 4361** CAPI3REF: Overload A Function For A Virtual Table 4362** EXPERIMENTAL 4363** 4364** ^(Virtual tables can provide alternative implementations of functions 4365** using the [xFindFunction] method of the [virtual table module]. 4366** But global versions of those functions 4367** must exist in order to be overloaded.)^ 4368** 4369** ^(This API makes sure a global version of a function with a particular 4370** name and number of parameters exists. If no such function exists 4371** before this API is called, a new function is created.)^ ^The implementation 4372** of the new function always causes an exception to be thrown. So 4373** the new function is not good for anything by itself. Its only 4374** purpose is to be a placeholder function that can be overloaded 4375** by a [virtual table]. 4376*/ 4377SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 4378 4379/* 4380** The interface to the virtual-table mechanism defined above (back up 4381** to a comment remarkably similar to this one) is currently considered 4382** to be experimental. The interface might change in incompatible ways. 4383** If this is a problem for you, do not use the interface at this time. 4384** 4385** When the virtual-table mechanism stabilizes, we will declare the 4386** interface fixed, support it indefinitely, and remove this comment. 4387** 4388****** EXPERIMENTAL - subject to change without notice ************** 4389*/ 4390 4391/* 4392** CAPI3REF: A Handle To An Open BLOB 4393** KEYWORDS: {BLOB handle} {BLOB handles} 4394** 4395** An instance of this object represents an open BLOB on which 4396** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 4397** ^Objects of this type are created by [sqlite3_blob_open()] 4398** and destroyed by [sqlite3_blob_close()]. 4399** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 4400** can be used to read or write small subsections of the BLOB. 4401** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 4402*/ 4403typedef struct sqlite3_blob sqlite3_blob; 4404 4405/* 4406** CAPI3REF: Open A BLOB For Incremental I/O 4407** 4408** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 4409** in row iRow, column zColumn, table zTable in database zDb; 4410** in other words, the same BLOB that would be selected by: 4411** 4412** <pre> 4413** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 4414** </pre>)^ 4415** 4416** ^If the flags parameter is non-zero, then the BLOB is opened for read 4417** and write access. ^If it is zero, the BLOB is opened for read access. 4418** ^It is not possible to open a column that is part of an index or primary 4419** key for writing. ^If [foreign key constraints] are enabled, it is 4420** not possible to open a column that is part of a [child key] for writing. 4421** 4422** ^Note that the database name is not the filename that contains 4423** the database but rather the symbolic name of the database that 4424** appears after the AS keyword when the database is connected using [ATTACH]. 4425** ^For the main database file, the database name is "main". 4426** ^For TEMP tables, the database name is "temp". 4427** 4428** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 4429** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 4430** to be a null pointer.)^ 4431** ^This function sets the [database connection] error code and message 4432** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 4433** functions. ^Note that the *ppBlob variable is always initialized in a 4434** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 4435** regardless of the success or failure of this routine. 4436** 4437** ^(If the row that a BLOB handle points to is modified by an 4438** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 4439** then the BLOB handle is marked as "expired". 4440** This is true if any column of the row is changed, even a column 4441** other than the one the BLOB handle is open on.)^ 4442** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 4443** a expired BLOB handle fail with an return code of [SQLITE_ABORT]. 4444** ^(Changes written into a BLOB prior to the BLOB expiring are not 4445** rolled back by the expiration of the BLOB. Such changes will eventually 4446** commit if the transaction continues to completion.)^ 4447** 4448** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 4449** the opened blob. ^The size of a blob may not be changed by this 4450** interface. Use the [UPDATE] SQL command to change the size of a 4451** blob. 4452** 4453** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 4454** and the built-in [zeroblob] SQL function can be used, if desired, 4455** to create an empty, zero-filled blob in which to read or write using 4456** this interface. 4457** 4458** To avoid a resource leak, every open [BLOB handle] should eventually 4459** be released by a call to [sqlite3_blob_close()]. 4460*/ 4461SQLITE_API int sqlite3_blob_open( 4462 sqlite3*, 4463 const char *zDb, 4464 const char *zTable, 4465 const char *zColumn, 4466 sqlite3_int64 iRow, 4467 int flags, 4468 sqlite3_blob **ppBlob 4469); 4470 4471/* 4472** CAPI3REF: Close A BLOB Handle 4473** 4474** ^Closes an open [BLOB handle]. 4475** 4476** ^Closing a BLOB shall cause the current transaction to commit 4477** if there are no other BLOBs, no pending prepared statements, and the 4478** database connection is in [autocommit mode]. 4479** ^If any writes were made to the BLOB, they might be held in cache 4480** until the close operation if they will fit. 4481** 4482** ^(Closing the BLOB often forces the changes 4483** out to disk and so if any I/O errors occur, they will likely occur 4484** at the time when the BLOB is closed. Any errors that occur during 4485** closing are reported as a non-zero return value.)^ 4486** 4487** ^(The BLOB is closed unconditionally. Even if this routine returns 4488** an error code, the BLOB is still closed.)^ 4489** 4490** ^Calling this routine with a null pointer (such as would be returned 4491** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 4492*/ 4493SQLITE_API int sqlite3_blob_close(sqlite3_blob *); 4494 4495/* 4496** CAPI3REF: Return The Size Of An Open BLOB 4497** 4498** ^Returns the size in bytes of the BLOB accessible via the 4499** successfully opened [BLOB handle] in its only argument. ^The 4500** incremental blob I/O routines can only read or overwriting existing 4501** blob content; they cannot change the size of a blob. 4502** 4503** This routine only works on a [BLOB handle] which has been created 4504** by a prior successful call to [sqlite3_blob_open()] and which has not 4505** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4506** to this routine results in undefined and probably undesirable behavior. 4507*/ 4508SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *); 4509 4510/* 4511** CAPI3REF: Read Data From A BLOB Incrementally 4512** 4513** ^(This function is used to read data from an open [BLOB handle] into a 4514** caller-supplied buffer. N bytes of data are copied into buffer Z 4515** from the open BLOB, starting at offset iOffset.)^ 4516** 4517** ^If offset iOffset is less than N bytes from the end of the BLOB, 4518** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 4519** less than zero, [SQLITE_ERROR] is returned and no data is read. 4520** ^The size of the blob (and hence the maximum value of N+iOffset) 4521** can be determined using the [sqlite3_blob_bytes()] interface. 4522** 4523** ^An attempt to read from an expired [BLOB handle] fails with an 4524** error code of [SQLITE_ABORT]. 4525** 4526** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 4527** Otherwise, an [error code] or an [extended error code] is returned.)^ 4528** 4529** This routine only works on a [BLOB handle] which has been created 4530** by a prior successful call to [sqlite3_blob_open()] and which has not 4531** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4532** to this routine results in undefined and probably undesirable behavior. 4533** 4534** See also: [sqlite3_blob_write()]. 4535*/ 4536SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 4537 4538/* 4539** CAPI3REF: Write Data Into A BLOB Incrementally 4540** 4541** ^This function is used to write data into an open [BLOB handle] from a 4542** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 4543** into the open BLOB, starting at offset iOffset. 4544** 4545** ^If the [BLOB handle] passed as the first argument was not opened for 4546** writing (the flags parameter to [sqlite3_blob_open()] was zero), 4547** this function returns [SQLITE_READONLY]. 4548** 4549** ^This function may only modify the contents of the BLOB; it is 4550** not possible to increase the size of a BLOB using this API. 4551** ^If offset iOffset is less than N bytes from the end of the BLOB, 4552** [SQLITE_ERROR] is returned and no data is written. ^If N is 4553** less than zero [SQLITE_ERROR] is returned and no data is written. 4554** The size of the BLOB (and hence the maximum value of N+iOffset) 4555** can be determined using the [sqlite3_blob_bytes()] interface. 4556** 4557** ^An attempt to write to an expired [BLOB handle] fails with an 4558** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 4559** before the [BLOB handle] expired are not rolled back by the 4560** expiration of the handle, though of course those changes might 4561** have been overwritten by the statement that expired the BLOB handle 4562** or by other independent statements. 4563** 4564** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 4565** Otherwise, an [error code] or an [extended error code] is returned.)^ 4566** 4567** This routine only works on a [BLOB handle] which has been created 4568** by a prior successful call to [sqlite3_blob_open()] and which has not 4569** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4570** to this routine results in undefined and probably undesirable behavior. 4571** 4572** See also: [sqlite3_blob_read()]. 4573*/ 4574SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 4575 4576/* 4577** CAPI3REF: Virtual File System Objects 4578** 4579** A virtual filesystem (VFS) is an [sqlite3_vfs] object 4580** that SQLite uses to interact 4581** with the underlying operating system. Most SQLite builds come with a 4582** single default VFS that is appropriate for the host computer. 4583** New VFSes can be registered and existing VFSes can be unregistered. 4584** The following interfaces are provided. 4585** 4586** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 4587** ^Names are case sensitive. 4588** ^Names are zero-terminated UTF-8 strings. 4589** ^If there is no match, a NULL pointer is returned. 4590** ^If zVfsName is NULL then the default VFS is returned. 4591** 4592** ^New VFSes are registered with sqlite3_vfs_register(). 4593** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 4594** ^The same VFS can be registered multiple times without injury. 4595** ^To make an existing VFS into the default VFS, register it again 4596** with the makeDflt flag set. If two different VFSes with the 4597** same name are registered, the behavior is undefined. If a 4598** VFS is registered with a name that is NULL or an empty string, 4599** then the behavior is undefined. 4600** 4601** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 4602** ^(If the default VFS is unregistered, another VFS is chosen as 4603** the default. The choice for the new VFS is arbitrary.)^ 4604*/ 4605SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 4606SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 4607SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*); 4608 4609/* 4610** CAPI3REF: Mutexes 4611** 4612** The SQLite core uses these routines for thread 4613** synchronization. Though they are intended for internal 4614** use by SQLite, code that links against SQLite is 4615** permitted to use any of these routines. 4616** 4617** The SQLite source code contains multiple implementations 4618** of these mutex routines. An appropriate implementation 4619** is selected automatically at compile-time. ^(The following 4620** implementations are available in the SQLite core: 4621** 4622** <ul> 4623** <li> SQLITE_MUTEX_OS2 4624** <li> SQLITE_MUTEX_PTHREAD 4625** <li> SQLITE_MUTEX_W32 4626** <li> SQLITE_MUTEX_NOOP 4627** </ul>)^ 4628** 4629** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 4630** that does no real locking and is appropriate for use in 4631** a single-threaded application. ^The SQLITE_MUTEX_OS2, 4632** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations 4633** are appropriate for use on OS/2, Unix, and Windows. 4634** 4635** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 4636** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 4637** implementation is included with the library. In this case the 4638** application must supply a custom mutex implementation using the 4639** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 4640** before calling sqlite3_initialize() or any other public sqlite3_ 4641** function that calls sqlite3_initialize().)^ 4642** 4643** ^The sqlite3_mutex_alloc() routine allocates a new 4644** mutex and returns a pointer to it. ^If it returns NULL 4645** that means that a mutex could not be allocated. ^SQLite 4646** will unwind its stack and return an error. ^(The argument 4647** to sqlite3_mutex_alloc() is one of these integer constants: 4648** 4649** <ul> 4650** <li> SQLITE_MUTEX_FAST 4651** <li> SQLITE_MUTEX_RECURSIVE 4652** <li> SQLITE_MUTEX_STATIC_MASTER 4653** <li> SQLITE_MUTEX_STATIC_MEM 4654** <li> SQLITE_MUTEX_STATIC_MEM2 4655** <li> SQLITE_MUTEX_STATIC_PRNG 4656** <li> SQLITE_MUTEX_STATIC_LRU 4657** <li> SQLITE_MUTEX_STATIC_LRU2 4658** </ul>)^ 4659** 4660** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 4661** cause sqlite3_mutex_alloc() to create 4662** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 4663** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 4664** The mutex implementation does not need to make a distinction 4665** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 4666** not want to. ^SQLite will only request a recursive mutex in 4667** cases where it really needs one. ^If a faster non-recursive mutex 4668** implementation is available on the host platform, the mutex subsystem 4669** might return such a mutex in response to SQLITE_MUTEX_FAST. 4670** 4671** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 4672** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 4673** a pointer to a static preexisting mutex. ^Six static mutexes are 4674** used by the current version of SQLite. Future versions of SQLite 4675** may add additional static mutexes. Static mutexes are for internal 4676** use by SQLite only. Applications that use SQLite mutexes should 4677** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 4678** SQLITE_MUTEX_RECURSIVE. 4679** 4680** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 4681** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 4682** returns a different mutex on every call. ^But for the static 4683** mutex types, the same mutex is returned on every call that has 4684** the same type number. 4685** 4686** ^The sqlite3_mutex_free() routine deallocates a previously 4687** allocated dynamic mutex. ^SQLite is careful to deallocate every 4688** dynamic mutex that it allocates. The dynamic mutexes must not be in 4689** use when they are deallocated. Attempting to deallocate a static 4690** mutex results in undefined behavior. ^SQLite never deallocates 4691** a static mutex. 4692** 4693** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 4694** to enter a mutex. ^If another thread is already within the mutex, 4695** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 4696** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 4697** upon successful entry. ^(Mutexes created using 4698** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 4699** In such cases the, 4700** mutex must be exited an equal number of times before another thread 4701** can enter.)^ ^(If the same thread tries to enter any other 4702** kind of mutex more than once, the behavior is undefined. 4703** SQLite will never exhibit 4704** such behavior in its own use of mutexes.)^ 4705** 4706** ^(Some systems (for example, Windows 95) do not support the operation 4707** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 4708** will always return SQLITE_BUSY. The SQLite core only ever uses 4709** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 4710** 4711** ^The sqlite3_mutex_leave() routine exits a mutex that was 4712** previously entered by the same thread. ^(The behavior 4713** is undefined if the mutex is not currently entered by the 4714** calling thread or is not currently allocated. SQLite will 4715** never do either.)^ 4716** 4717** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 4718** sqlite3_mutex_leave() is a NULL pointer, then all three routines 4719** behave as no-ops. 4720** 4721** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 4722*/ 4723SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int); 4724SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*); 4725SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*); 4726SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*); 4727SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*); 4728 4729/* 4730** CAPI3REF: Mutex Methods Object 4731** EXPERIMENTAL 4732** 4733** An instance of this structure defines the low-level routines 4734** used to allocate and use mutexes. 4735** 4736** Usually, the default mutex implementations provided by SQLite are 4737** sufficient, however the user has the option of substituting a custom 4738** implementation for specialized deployments or systems for which SQLite 4739** does not provide a suitable implementation. In this case, the user 4740** creates and populates an instance of this structure to pass 4741** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 4742** Additionally, an instance of this structure can be used as an 4743** output variable when querying the system for the current mutex 4744** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 4745** 4746** ^The xMutexInit method defined by this structure is invoked as 4747** part of system initialization by the sqlite3_initialize() function. 4748** ^The xMutexInit routine is calle by SQLite exactly once for each 4749** effective call to [sqlite3_initialize()]. 4750** 4751** ^The xMutexEnd method defined by this structure is invoked as 4752** part of system shutdown by the sqlite3_shutdown() function. The 4753** implementation of this method is expected to release all outstanding 4754** resources obtained by the mutex methods implementation, especially 4755** those obtained by the xMutexInit method. ^The xMutexEnd() 4756** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 4757** 4758** ^(The remaining seven methods defined by this structure (xMutexAlloc, 4759** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 4760** xMutexNotheld) implement the following interfaces (respectively): 4761** 4762** <ul> 4763** <li> [sqlite3_mutex_alloc()] </li> 4764** <li> [sqlite3_mutex_free()] </li> 4765** <li> [sqlite3_mutex_enter()] </li> 4766** <li> [sqlite3_mutex_try()] </li> 4767** <li> [sqlite3_mutex_leave()] </li> 4768** <li> [sqlite3_mutex_held()] </li> 4769** <li> [sqlite3_mutex_notheld()] </li> 4770** </ul>)^ 4771** 4772** The only difference is that the public sqlite3_XXX functions enumerated 4773** above silently ignore any invocations that pass a NULL pointer instead 4774** of a valid mutex handle. The implementations of the methods defined 4775** by this structure are not required to handle this case, the results 4776** of passing a NULL pointer instead of a valid mutex handle are undefined 4777** (i.e. it is acceptable to provide an implementation that segfaults if 4778** it is passed a NULL pointer). 4779** 4780** The xMutexInit() method must be threadsafe. ^It must be harmless to 4781** invoke xMutexInit() mutiple times within the same process and without 4782** intervening calls to xMutexEnd(). Second and subsequent calls to 4783** xMutexInit() must be no-ops. 4784** 4785** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 4786** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 4787** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 4788** memory allocation for a fast or recursive mutex. 4789** 4790** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 4791** called, but only if the prior call to xMutexInit returned SQLITE_OK. 4792** If xMutexInit fails in any way, it is expected to clean up after itself 4793** prior to returning. 4794*/ 4795typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 4796struct sqlite3_mutex_methods { 4797 int (*xMutexInit)(void); 4798 int (*xMutexEnd)(void); 4799 sqlite3_mutex *(*xMutexAlloc)(int); 4800 void (*xMutexFree)(sqlite3_mutex *); 4801 void (*xMutexEnter)(sqlite3_mutex *); 4802 int (*xMutexTry)(sqlite3_mutex *); 4803 void (*xMutexLeave)(sqlite3_mutex *); 4804 int (*xMutexHeld)(sqlite3_mutex *); 4805 int (*xMutexNotheld)(sqlite3_mutex *); 4806}; 4807 4808/* 4809** CAPI3REF: Mutex Verification Routines 4810** 4811** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 4812** are intended for use inside assert() statements. ^The SQLite core 4813** never uses these routines except inside an assert() and applications 4814** are advised to follow the lead of the core. ^The SQLite core only 4815** provides implementations for these routines when it is compiled 4816** with the SQLITE_DEBUG flag. ^External mutex implementations 4817** are only required to provide these routines if SQLITE_DEBUG is 4818** defined and if NDEBUG is not defined. 4819** 4820** ^These routines should return true if the mutex in their argument 4821** is held or not held, respectively, by the calling thread. 4822** 4823** ^The implementation is not required to provided versions of these 4824** routines that actually work. If the implementation does not provide working 4825** versions of these routines, it should at least provide stubs that always 4826** return true so that one does not get spurious assertion failures. 4827** 4828** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 4829** the routine should return 1. This seems counter-intuitive since 4830** clearly the mutex cannot be held if it does not exist. But the 4831** the reason the mutex does not exist is because the build is not 4832** using mutexes. And we do not want the assert() containing the 4833** call to sqlite3_mutex_held() to fail, so a non-zero return is 4834** the appropriate thing to do. ^The sqlite3_mutex_notheld() 4835** interface should also return 1 when given a NULL pointer. 4836*/ 4837#ifndef NDEBUG 4838SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*); 4839SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*); 4840#endif 4841 4842/* 4843** CAPI3REF: Mutex Types 4844** 4845** The [sqlite3_mutex_alloc()] interface takes a single argument 4846** which is one of these integer constants. 4847** 4848** The set of static mutexes may change from one SQLite release to the 4849** next. Applications that override the built-in mutex logic must be 4850** prepared to accommodate additional static mutexes. 4851*/ 4852#define SQLITE_MUTEX_FAST 0 4853#define SQLITE_MUTEX_RECURSIVE 1 4854#define SQLITE_MUTEX_STATIC_MASTER 2 4855#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 4856#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 4857#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 4858#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 4859#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 4860#define SQLITE_MUTEX_STATIC_LRU2 7 /* lru page list */ 4861 4862/* 4863** CAPI3REF: Retrieve the mutex for a database connection 4864** 4865** ^This interface returns a pointer the [sqlite3_mutex] object that 4866** serializes access to the [database connection] given in the argument 4867** when the [threading mode] is Serialized. 4868** ^If the [threading mode] is Single-thread or Multi-thread then this 4869** routine returns a NULL pointer. 4870*/ 4871SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 4872 4873/* 4874** CAPI3REF: Low-Level Control Of Database Files 4875** 4876** ^The [sqlite3_file_control()] interface makes a direct call to the 4877** xFileControl method for the [sqlite3_io_methods] object associated 4878** with a particular database identified by the second argument. ^The 4879** name of the database "main" for the main database or "temp" for the 4880** TEMP database, or the name that appears after the AS keyword for 4881** databases that are added using the [ATTACH] SQL command. 4882** ^A NULL pointer can be used in place of "main" to refer to the 4883** main database file. 4884** ^The third and fourth parameters to this routine 4885** are passed directly through to the second and third parameters of 4886** the xFileControl method. ^The return value of the xFileControl 4887** method becomes the return value of this routine. 4888** 4889** ^If the second parameter (zDbName) does not match the name of any 4890** open database file, then SQLITE_ERROR is returned. ^This error 4891** code is not remembered and will not be recalled by [sqlite3_errcode()] 4892** or [sqlite3_errmsg()]. The underlying xFileControl method might 4893** also return SQLITE_ERROR. There is no way to distinguish between 4894** an incorrect zDbName and an SQLITE_ERROR return from the underlying 4895** xFileControl method. 4896** 4897** See also: [SQLITE_FCNTL_LOCKSTATE] 4898*/ 4899SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 4900 4901/* 4902** CAPI3REF: Testing Interface 4903** 4904** ^The sqlite3_test_control() interface is used to read out internal 4905** state of SQLite and to inject faults into SQLite for testing 4906** purposes. ^The first parameter is an operation code that determines 4907** the number, meaning, and operation of all subsequent parameters. 4908** 4909** This interface is not for use by applications. It exists solely 4910** for verifying the correct operation of the SQLite library. Depending 4911** on how the SQLite library is compiled, this interface might not exist. 4912** 4913** The details of the operation codes, their meanings, the parameters 4914** they take, and what they do are all subject to change without notice. 4915** Unlike most of the SQLite API, this function is not guaranteed to 4916** operate consistently from one release to the next. 4917*/ 4918SQLITE_API int sqlite3_test_control(int op, ...); 4919 4920/* 4921** CAPI3REF: Testing Interface Operation Codes 4922** 4923** These constants are the valid operation code parameters used 4924** as the first argument to [sqlite3_test_control()]. 4925** 4926** These parameters and their meanings are subject to change 4927** without notice. These values are for testing purposes only. 4928** Applications should not use any of these parameters or the 4929** [sqlite3_test_control()] interface. 4930*/ 4931#define SQLITE_TESTCTRL_FIRST 5 4932#define SQLITE_TESTCTRL_PRNG_SAVE 5 4933#define SQLITE_TESTCTRL_PRNG_RESTORE 6 4934#define SQLITE_TESTCTRL_PRNG_RESET 7 4935#define SQLITE_TESTCTRL_BITVEC_TEST 8 4936#define SQLITE_TESTCTRL_FAULT_INSTALL 9 4937#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 4938#define SQLITE_TESTCTRL_PENDING_BYTE 11 4939#define SQLITE_TESTCTRL_ASSERT 12 4940#define SQLITE_TESTCTRL_ALWAYS 13 4941#define SQLITE_TESTCTRL_RESERVE 14 4942#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 4943#define SQLITE_TESTCTRL_ISKEYWORD 16 4944#define SQLITE_TESTCTRL_LAST 16 4945 4946/* 4947** CAPI3REF: SQLite Runtime Status 4948** EXPERIMENTAL 4949** 4950** ^This interface is used to retrieve runtime status information 4951** about the preformance of SQLite, and optionally to reset various 4952** highwater marks. ^The first argument is an integer code for 4953** the specific parameter to measure. ^(Recognized integer codes 4954** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].)^ 4955** ^The current value of the parameter is returned into *pCurrent. 4956** ^The highest recorded value is returned in *pHighwater. ^If the 4957** resetFlag is true, then the highest record value is reset after 4958** *pHighwater is written. ^(Some parameters do not record the highest 4959** value. For those parameters 4960** nothing is written into *pHighwater and the resetFlag is ignored.)^ 4961** ^(Other parameters record only the highwater mark and not the current 4962** value. For these latter parameters nothing is written into *pCurrent.)^ 4963** 4964** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 4965** non-zero [error code] on failure. 4966** 4967** This routine is threadsafe but is not atomic. This routine can be 4968** called while other threads are running the same or different SQLite 4969** interfaces. However the values returned in *pCurrent and 4970** *pHighwater reflect the status of SQLite at different points in time 4971** and it is possible that another thread might change the parameter 4972** in between the times when *pCurrent and *pHighwater are written. 4973** 4974** See also: [sqlite3_db_status()] 4975*/ 4976SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 4977 4978 4979/* 4980** CAPI3REF: Status Parameters 4981** EXPERIMENTAL 4982** 4983** These integer constants designate various run-time status parameters 4984** that can be returned by [sqlite3_status()]. 4985** 4986** <dl> 4987** ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 4988** <dd>This parameter is the current amount of memory checked out 4989** using [sqlite3_malloc()], either directly or indirectly. The 4990** figure includes calls made to [sqlite3_malloc()] by the application 4991** and internal memory usage by the SQLite library. Scratch memory 4992** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 4993** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 4994** this parameter. The amount returned is the sum of the allocation 4995** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 4996** 4997** ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 4998** <dd>This parameter records the largest memory allocation request 4999** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 5000** internal equivalents). Only the value returned in the 5001** *pHighwater parameter to [sqlite3_status()] is of interest. 5002** The value written into the *pCurrent parameter is undefined.</dd>)^ 5003** 5004** ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 5005** <dd>This parameter returns the number of pages used out of the 5006** [pagecache memory allocator] that was configured using 5007** [SQLITE_CONFIG_PAGECACHE]. The 5008** value returned is in pages, not in bytes.</dd>)^ 5009** 5010** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5011** <dd>This parameter returns the number of bytes of page cache 5012** allocation which could not be statisfied by the [SQLITE_CONFIG_PAGECACHE] 5013** buffer and where forced to overflow to [sqlite3_malloc()]. The 5014** returned value includes allocations that overflowed because they 5015** where too large (they were larger than the "sz" parameter to 5016** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 5017** no space was left in the page cache.</dd>)^ 5018** 5019** ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 5020** <dd>This parameter records the largest memory allocation request 5021** handed to [pagecache memory allocator]. Only the value returned in the 5022** *pHighwater parameter to [sqlite3_status()] is of interest. 5023** The value written into the *pCurrent parameter is undefined.</dd>)^ 5024** 5025** ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 5026** <dd>This parameter returns the number of allocations used out of the 5027** [scratch memory allocator] configured using 5028** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5029** in bytes. Since a single thread may only have one scratch allocation 5030** outstanding at time, this parameter also reports the number of threads 5031** using scratch memory at the same time.</dd>)^ 5032** 5033** ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5034** <dd>This parameter returns the number of bytes of scratch memory 5035** allocation which could not be statisfied by the [SQLITE_CONFIG_SCRATCH] 5036** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5037** returned include overflows because the requested allocation was too 5038** larger (that is, because the requested allocation was larger than the 5039** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5040** slots were available. 5041** </dd>)^ 5042** 5043** ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5044** <dd>This parameter records the largest memory allocation request 5045** handed to [scratch memory allocator]. Only the value returned in the 5046** *pHighwater parameter to [sqlite3_status()] is of interest. 5047** The value written into the *pCurrent parameter is undefined.</dd>)^ 5048** 5049** ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 5050** <dd>This parameter records the deepest parser stack. It is only 5051** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 5052** </dl> 5053** 5054** New status parameters may be added from time to time. 5055*/ 5056#define SQLITE_STATUS_MEMORY_USED 0 5057#define SQLITE_STATUS_PAGECACHE_USED 1 5058#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5059#define SQLITE_STATUS_SCRATCH_USED 3 5060#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5061#define SQLITE_STATUS_MALLOC_SIZE 5 5062#define SQLITE_STATUS_PARSER_STACK 6 5063#define SQLITE_STATUS_PAGECACHE_SIZE 7 5064#define SQLITE_STATUS_SCRATCH_SIZE 8 5065 5066/* 5067** CAPI3REF: Database Connection Status 5068** EXPERIMENTAL 5069** 5070** ^This interface is used to retrieve runtime status information 5071** about a single [database connection]. ^The first argument is the 5072** database connection object to be interrogated. ^The second argument 5073** is the parameter to interrogate. ^Currently, the only allowed value 5074** for the second parameter is [SQLITE_DBSTATUS_LOOKASIDE_USED]. 5075** Additional options will likely appear in future releases of SQLite. 5076** 5077** ^The current value of the requested parameter is written into *pCur 5078** and the highest instantaneous value is written into *pHiwtr. ^If 5079** the resetFlg is true, then the highest instantaneous value is 5080** reset back down to the current value. 5081** 5082** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5083*/ 5084SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5085 5086/* 5087** CAPI3REF: Status Parameters for database connections 5088** EXPERIMENTAL 5089** 5090** These constants are the available integer "verbs" that can be passed as 5091** the second argument to the [sqlite3_db_status()] interface. 5092** 5093** New verbs may be added in future releases of SQLite. Existing verbs 5094** might be discontinued. Applications should check the return code from 5095** [sqlite3_db_status()] to make sure that the call worked. 5096** The [sqlite3_db_status()] interface will return a non-zero error code 5097** if a discontinued or unsupported verb is invoked. 5098** 5099** <dl> 5100** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5101** <dd>This parameter returns the number of lookaside memory slots currently 5102** checked out.</dd>)^ 5103** </dl> 5104*/ 5105#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 5106 5107 5108/* 5109** CAPI3REF: Prepared Statement Status 5110** EXPERIMENTAL 5111** 5112** ^(Each prepared statement maintains various 5113** [SQLITE_STMTSTATUS_SORT | counters] that measure the number 5114** of times it has performed specific operations.)^ These counters can 5115** be used to monitor the performance characteristics of the prepared 5116** statements. For example, if the number of table steps greatly exceeds 5117** the number of table searches or result rows, that would tend to indicate 5118** that the prepared statement is using a full table scan rather than 5119** an index. 5120** 5121** ^(This interface is used to retrieve and reset counter values from 5122** a [prepared statement]. The first argument is the prepared statement 5123** object to be interrogated. The second argument 5124** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter] 5125** to be interrogated.)^ 5126** ^The current value of the requested counter is returned. 5127** ^If the resetFlg is true, then the counter is reset to zero after this 5128** interface call returns. 5129** 5130** See also: [sqlite3_status()] and [sqlite3_db_status()]. 5131*/ 5132SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 5133 5134/* 5135** CAPI3REF: Status Parameters for prepared statements 5136** EXPERIMENTAL 5137** 5138** These preprocessor macros define integer codes that name counter 5139** values associated with the [sqlite3_stmt_status()] interface. 5140** The meanings of the various counters are as follows: 5141** 5142** <dl> 5143** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 5144** <dd>^This is the number of times that SQLite has stepped forward in 5145** a table as part of a full table scan. Large numbers for this counter 5146** may indicate opportunities for performance improvement through 5147** careful use of indices.</dd> 5148** 5149** <dt>SQLITE_STMTSTATUS_SORT</dt> 5150** <dd>^This is the number of sort operations that have occurred. 5151** A non-zero value in this counter may indicate an opportunity to 5152** improvement performance through careful use of indices.</dd> 5153** 5154** </dl> 5155*/ 5156#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 5157#define SQLITE_STMTSTATUS_SORT 2 5158 5159/* 5160** CAPI3REF: Custom Page Cache Object 5161** EXPERIMENTAL 5162** 5163** The sqlite3_pcache type is opaque. It is implemented by 5164** the pluggable module. The SQLite core has no knowledge of 5165** its size or internal structure and never deals with the 5166** sqlite3_pcache object except by holding and passing pointers 5167** to the object. 5168** 5169** See [sqlite3_pcache_methods] for additional information. 5170*/ 5171typedef struct sqlite3_pcache sqlite3_pcache; 5172 5173/* 5174** CAPI3REF: Application Defined Page Cache. 5175** KEYWORDS: {page cache} 5176** EXPERIMENTAL 5177** 5178** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can 5179** register an alternative page cache implementation by passing in an 5180** instance of the sqlite3_pcache_methods structure.)^ The majority of the 5181** heap memory used by SQLite is used by the page cache to cache data read 5182** from, or ready to be written to, the database file. By implementing a 5183** custom page cache using this API, an application can control more 5184** precisely the amount of memory consumed by SQLite, the way in which 5185** that memory is allocated and released, and the policies used to 5186** determine exactly which parts of a database file are cached and for 5187** how long. 5188** 5189** ^(The contents of the sqlite3_pcache_methods structure are copied to an 5190** internal buffer by SQLite within the call to [sqlite3_config]. Hence 5191** the application may discard the parameter after the call to 5192** [sqlite3_config()] returns.)^ 5193** 5194** ^The xInit() method is called once for each call to [sqlite3_initialize()] 5195** (usually only once during the lifetime of the process). ^(The xInit() 5196** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^ 5197** ^The xInit() method can set up up global structures and/or any mutexes 5198** required by the custom page cache implementation. 5199** 5200** ^The xShutdown() method is called from within [sqlite3_shutdown()], 5201** if the application invokes this API. It can be used to clean up 5202** any outstanding resources before process shutdown, if required. 5203** 5204** ^SQLite holds a [SQLITE_MUTEX_RECURSIVE] mutex when it invokes 5205** the xInit method, so the xInit method need not be threadsafe. ^The 5206** xShutdown method is only called from [sqlite3_shutdown()] so it does 5207** not need to be threadsafe either. All other methods must be threadsafe 5208** in multithreaded applications. 5209** 5210** ^SQLite will never invoke xInit() more than once without an intervening 5211** call to xShutdown(). 5212** 5213** ^The xCreate() method is used to construct a new cache instance. SQLite 5214** will typically create one cache instance for each open database file, 5215** though this is not guaranteed. ^The 5216** first parameter, szPage, is the size in bytes of the pages that must 5217** be allocated by the cache. ^szPage will not be a power of two. ^szPage 5218** will the page size of the database file that is to be cached plus an 5219** increment (here called "R") of about 100 or 200. ^SQLite will use the 5220** extra R bytes on each page to store metadata about the underlying 5221** database page on disk. The value of R depends 5222** on the SQLite version, the target platform, and how SQLite was compiled. 5223** ^R is constant for a particular build of SQLite. ^The second argument to 5224** xCreate(), bPurgeable, is true if the cache being created will 5225** be used to cache database pages of a file stored on disk, or 5226** false if it is used for an in-memory database. ^The cache implementation 5227** does not have to do anything special based with the value of bPurgeable; 5228** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 5229** never invoke xUnpin() except to deliberately delete a page. 5230** ^In other words, a cache created with bPurgeable set to false will 5231** never contain any unpinned pages. 5232** 5233** ^(The xCachesize() method may be called at any time by SQLite to set the 5234** suggested maximum cache-size (number of pages stored by) the cache 5235** instance passed as the first argument. This is the value configured using 5236** the SQLite "[PRAGMA cache_size]" command.)^ ^As with the bPurgeable 5237** parameter, the implementation is not required to do anything with this 5238** value; it is advisory only. 5239** 5240** ^The xPagecount() method should return the number of pages currently 5241** stored in the cache. 5242** 5243** ^The xFetch() method is used to fetch a page and return a pointer to it. 5244** ^A 'page', in this context, is a buffer of szPage bytes aligned at an 5245** 8-byte boundary. ^The page to be fetched is determined by the key. ^The 5246** mimimum key value is 1. After it has been retrieved using xFetch, the page 5247** is considered to be "pinned". 5248** 5249** ^If the requested page is already in the page cache, then the page cache 5250** implementation must return a pointer to the page buffer with its content 5251** intact. ^(If the requested page is not already in the cache, then the 5252** behavior of the cache implementation is determined by the value of the 5253** createFlag parameter passed to xFetch, according to the following table: 5254** 5255** <table border=1 width=85% align=center> 5256** <tr><th> createFlag <th> Behaviour when page is not already in cache 5257** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 5258** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 5259** Otherwise return NULL. 5260** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 5261** NULL if allocating a new page is effectively impossible. 5262** </table>)^ 5263** 5264** SQLite will normally invoke xFetch() with a createFlag of 0 or 1. If 5265** a call to xFetch() with createFlag==1 returns NULL, then SQLite will 5266** attempt to unpin one or more cache pages by spilling the content of 5267** pinned pages to disk and synching the operating system disk cache. After 5268** attempting to unpin pages, the xFetch() method will be invoked again with 5269** a createFlag of 2. 5270** 5271** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 5272** as its second argument. ^(If the third parameter, discard, is non-zero, 5273** then the page should be evicted from the cache. In this case SQLite 5274** assumes that the next time the page is retrieved from the cache using 5275** the xFetch() method, it will be zeroed.)^ ^If the discard parameter is 5276** zero, then the page is considered to be unpinned. ^The cache implementation 5277** may choose to evict unpinned pages at any time. 5278** 5279** ^(The cache is not required to perform any reference counting. A single 5280** call to xUnpin() unpins the page regardless of the number of prior calls 5281** to xFetch().)^ 5282** 5283** ^The xRekey() method is used to change the key value associated with the 5284** page passed as the second argument from oldKey to newKey. ^If the cache 5285** previously contains an entry associated with newKey, it should be 5286** discarded. ^Any prior cache entry associated with newKey is guaranteed not 5287** to be pinned. 5288** 5289** ^When SQLite calls the xTruncate() method, the cache must discard all 5290** existing cache entries with page numbers (keys) greater than or equal 5291** to the value of the iLimit parameter passed to xTruncate(). ^If any 5292** of these pages are pinned, they are implicitly unpinned, meaning that 5293** they can be safely discarded. 5294** 5295** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 5296** All resources associated with the specified cache should be freed. ^After 5297** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 5298** handle invalid, and will not use it with any other sqlite3_pcache_methods 5299** functions. 5300*/ 5301typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 5302struct sqlite3_pcache_methods { 5303 void *pArg; 5304 int (*xInit)(void*); 5305 void (*xShutdown)(void*); 5306 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 5307 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 5308 int (*xPagecount)(sqlite3_pcache*); 5309 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 5310 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 5311 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 5312 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 5313 void (*xDestroy)(sqlite3_pcache*); 5314}; 5315 5316/* 5317** CAPI3REF: Online Backup Object 5318** EXPERIMENTAL 5319** 5320** The sqlite3_backup object records state information about an ongoing 5321** online backup operation. ^The sqlite3_backup object is created by 5322** a call to [sqlite3_backup_init()] and is destroyed by a call to 5323** [sqlite3_backup_finish()]. 5324** 5325** See Also: [Using the SQLite Online Backup API] 5326*/ 5327typedef struct sqlite3_backup sqlite3_backup; 5328 5329/* 5330** CAPI3REF: Online Backup API. 5331** EXPERIMENTAL 5332** 5333** The backup API copies the content of one database into another. 5334** It is useful either for creating backups of databases or 5335** for copying in-memory databases to or from persistent files. 5336** 5337** See Also: [Using the SQLite Online Backup API] 5338** 5339** ^Exclusive access is required to the destination database for the 5340** duration of the operation. ^However the source database is only 5341** read-locked while it is actually being read; it is not locked 5342** continuously for the entire backup operation. ^Thus, the backup may be 5343** performed on a live source database without preventing other users from 5344** reading or writing to the source database while the backup is underway. 5345** 5346** ^(To perform a backup operation: 5347** <ol> 5348** <li><b>sqlite3_backup_init()</b> is called once to initialize the 5349** backup, 5350** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 5351** the data between the two databases, and finally 5352** <li><b>sqlite3_backup_finish()</b> is called to release all resources 5353** associated with the backup operation. 5354** </ol>)^ 5355** There should be exactly one call to sqlite3_backup_finish() for each 5356** successful call to sqlite3_backup_init(). 5357** 5358** <b>sqlite3_backup_init()</b> 5359** 5360** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 5361** [database connection] associated with the destination database 5362** and the database name, respectively. 5363** ^The database name is "main" for the main database, "temp" for the 5364** temporary database, or the name specified after the AS keyword in 5365** an [ATTACH] statement for an attached database. 5366** ^The S and M arguments passed to 5367** sqlite3_backup_init(D,N,S,M) identify the [database connection] 5368** and database name of the source database, respectively. 5369** ^The source and destination [database connections] (parameters S and D) 5370** must be different or else sqlite3_backup_init(D,N,S,M) will file with 5371** an error. 5372** 5373** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 5374** returned and an error code and error message are store3d in the 5375** destination [database connection] D. 5376** ^The error code and message for the failed call to sqlite3_backup_init() 5377** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 5378** [sqlite3_errmsg16()] functions. 5379** ^A successful call to sqlite3_backup_init() returns a pointer to an 5380** [sqlite3_backup] object. 5381** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 5382** sqlite3_backup_finish() functions to perform the specified backup 5383** operation. 5384** 5385** <b>sqlite3_backup_step()</b> 5386** 5387** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 5388** the source and destination databases specified by [sqlite3_backup] object B. 5389** ^If N is negative, all remaining source pages are copied. 5390** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 5391** are still more pages to be copied, then the function resturns [SQLITE_OK]. 5392** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 5393** from source to destination, then it returns [SQLITE_DONE]. 5394** ^If an error occurs while running sqlite3_backup_step(B,N), 5395** then an [error code] is returned. ^As well as [SQLITE_OK] and 5396** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 5397** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 5398** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 5399** 5400** ^The sqlite3_backup_step() might return [SQLITE_READONLY] if the destination 5401** database was opened read-only or if 5402** the destination is an in-memory database with a different page size 5403** from the source database. 5404** 5405** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 5406** the [sqlite3_busy_handler | busy-handler function] 5407** is invoked (if one is specified). ^If the 5408** busy-handler returns non-zero before the lock is available, then 5409** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 5410** sqlite3_backup_step() can be retried later. ^If the source 5411** [database connection] 5412** is being used to write to the source database when sqlite3_backup_step() 5413** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 5414** case the call to sqlite3_backup_step() can be retried later on. ^(If 5415** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 5416** [SQLITE_READONLY] is returned, then 5417** there is no point in retrying the call to sqlite3_backup_step(). These 5418** errors are considered fatal.)^ The application must accept 5419** that the backup operation has failed and pass the backup operation handle 5420** to the sqlite3_backup_finish() to release associated resources. 5421** 5422** ^The first call to sqlite3_backup_step() obtains an exclusive lock 5423** on the destination file. ^The exclusive lock is not released until either 5424** sqlite3_backup_finish() is called or the backup operation is complete 5425** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 5426** sqlite3_backup_step() obtains a [shared lock] on the source database that 5427** lasts for the duration of the sqlite3_backup_step() call. 5428** ^Because the source database is not locked between calls to 5429** sqlite3_backup_step(), the source database may be modified mid-way 5430** through the backup process. ^If the source database is modified by an 5431** external process or via a database connection other than the one being 5432** used by the backup operation, then the backup will be automatically 5433** restarted by the next call to sqlite3_backup_step(). ^If the source 5434** database is modified by the using the same database connection as is used 5435** by the backup operation, then the backup database is automatically 5436** updated at the same time. 5437** 5438** <b>sqlite3_backup_finish()</b> 5439** 5440** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 5441** application wishes to abandon the backup operation, the application 5442** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 5443** ^The sqlite3_backup_finish() interfaces releases all 5444** resources associated with the [sqlite3_backup] object. 5445** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 5446** active write-transaction on the destination database is rolled back. 5447** The [sqlite3_backup] object is invalid 5448** and may not be used following a call to sqlite3_backup_finish(). 5449** 5450** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 5451** sqlite3_backup_step() errors occurred, regardless or whether or not 5452** sqlite3_backup_step() completed. 5453** ^If an out-of-memory condition or IO error occurred during any prior 5454** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 5455** sqlite3_backup_finish() returns the corresponding [error code]. 5456** 5457** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 5458** is not a permanent error and does not affect the return value of 5459** sqlite3_backup_finish(). 5460** 5461** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b> 5462** 5463** ^Each call to sqlite3_backup_step() sets two values inside 5464** the [sqlite3_backup] object: the number of pages still to be backed 5465** up and the total number of pages in the source databae file. 5466** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 5467** retrieve these two values, respectively. 5468** 5469** ^The values returned by these functions are only updated by 5470** sqlite3_backup_step(). ^If the source database is modified during a backup 5471** operation, then the values are not updated to account for any extra 5472** pages that need to be updated or the size of the source database file 5473** changing. 5474** 5475** <b>Concurrent Usage of Database Handles</b> 5476** 5477** ^The source [database connection] may be used by the application for other 5478** purposes while a backup operation is underway or being initialized. 5479** ^If SQLite is compiled and configured to support threadsafe database 5480** connections, then the source database connection may be used concurrently 5481** from within other threads. 5482** 5483** However, the application must guarantee that the destination 5484** [database connection] is not passed to any other API (by any thread) after 5485** sqlite3_backup_init() is called and before the corresponding call to 5486** sqlite3_backup_finish(). SQLite does not currently check to see 5487** if the application incorrectly accesses the destination [database connection] 5488** and so no error code is reported, but the operations may malfunction 5489** nevertheless. Use of the destination database connection while a 5490** backup is in progress might also also cause a mutex deadlock. 5491** 5492** If running in [shared cache mode], the application must 5493** guarantee that the shared cache used by the destination database 5494** is not accessed while the backup is running. In practice this means 5495** that the application must guarantee that the disk file being 5496** backed up to is not accessed by any connection within the process, 5497** not just the specific connection that was passed to sqlite3_backup_init(). 5498** 5499** The [sqlite3_backup] object itself is partially threadsafe. Multiple 5500** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 5501** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 5502** APIs are not strictly speaking threadsafe. If they are invoked at the 5503** same time as another thread is invoking sqlite3_backup_step() it is 5504** possible that they return invalid values. 5505*/ 5506SQLITE_API sqlite3_backup *sqlite3_backup_init( 5507 sqlite3 *pDest, /* Destination database handle */ 5508 const char *zDestName, /* Destination database name */ 5509 sqlite3 *pSource, /* Source database handle */ 5510 const char *zSourceName /* Source database name */ 5511); 5512SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage); 5513SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p); 5514SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p); 5515SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p); 5516 5517/* 5518** CAPI3REF: Unlock Notification 5519** EXPERIMENTAL 5520** 5521** ^When running in shared-cache mode, a database operation may fail with 5522** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 5523** individual tables within the shared-cache cannot be obtained. See 5524** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 5525** ^This API may be used to register a callback that SQLite will invoke 5526** when the connection currently holding the required lock relinquishes it. 5527** ^This API is only available if the library was compiled with the 5528** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 5529** 5530** See Also: [Using the SQLite Unlock Notification Feature]. 5531** 5532** ^Shared-cache locks are released when a database connection concludes 5533** its current transaction, either by committing it or rolling it back. 5534** 5535** ^When a connection (known as the blocked connection) fails to obtain a 5536** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 5537** identity of the database connection (the blocking connection) that 5538** has locked the required resource is stored internally. ^After an 5539** application receives an SQLITE_LOCKED error, it may call the 5540** sqlite3_unlock_notify() method with the blocked connection handle as 5541** the first argument to register for a callback that will be invoked 5542** when the blocking connections current transaction is concluded. ^The 5543** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 5544** call that concludes the blocking connections transaction. 5545** 5546** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 5547** there is a chance that the blocking connection will have already 5548** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 5549** If this happens, then the specified callback is invoked immediately, 5550** from within the call to sqlite3_unlock_notify().)^ 5551** 5552** ^If the blocked connection is attempting to obtain a write-lock on a 5553** shared-cache table, and more than one other connection currently holds 5554** a read-lock on the same table, then SQLite arbitrarily selects one of 5555** the other connections to use as the blocking connection. 5556** 5557** ^(There may be at most one unlock-notify callback registered by a 5558** blocked connection. If sqlite3_unlock_notify() is called when the 5559** blocked connection already has a registered unlock-notify callback, 5560** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 5561** called with a NULL pointer as its second argument, then any existing 5562** unlock-notify callback is cancelled. ^The blocked connections 5563** unlock-notify callback may also be canceled by closing the blocked 5564** connection using [sqlite3_close()]. 5565** 5566** The unlock-notify callback is not reentrant. If an application invokes 5567** any sqlite3_xxx API functions from within an unlock-notify callback, a 5568** crash or deadlock may be the result. 5569** 5570** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 5571** returns SQLITE_OK. 5572** 5573** <b>Callback Invocation Details</b> 5574** 5575** When an unlock-notify callback is registered, the application provides a 5576** single void* pointer that is passed to the callback when it is invoked. 5577** However, the signature of the callback function allows SQLite to pass 5578** it an array of void* context pointers. The first argument passed to 5579** an unlock-notify callback is a pointer to an array of void* pointers, 5580** and the second is the number of entries in the array. 5581** 5582** When a blocking connections transaction is concluded, there may be 5583** more than one blocked connection that has registered for an unlock-notify 5584** callback. ^If two or more such blocked connections have specified the 5585** same callback function, then instead of invoking the callback function 5586** multiple times, it is invoked once with the set of void* context pointers 5587** specified by the blocked connections bundled together into an array. 5588** This gives the application an opportunity to prioritize any actions 5589** related to the set of unblocked database connections. 5590** 5591** <b>Deadlock Detection</b> 5592** 5593** Assuming that after registering for an unlock-notify callback a 5594** database waits for the callback to be issued before taking any further 5595** action (a reasonable assumption), then using this API may cause the 5596** application to deadlock. For example, if connection X is waiting for 5597** connection Y's transaction to be concluded, and similarly connection 5598** Y is waiting on connection X's transaction, then neither connection 5599** will proceed and the system may remain deadlocked indefinitely. 5600** 5601** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 5602** detection. ^If a given call to sqlite3_unlock_notify() would put the 5603** system in a deadlocked state, then SQLITE_LOCKED is returned and no 5604** unlock-notify callback is registered. The system is said to be in 5605** a deadlocked state if connection A has registered for an unlock-notify 5606** callback on the conclusion of connection B's transaction, and connection 5607** B has itself registered for an unlock-notify callback when connection 5608** A's transaction is concluded. ^Indirect deadlock is also detected, so 5609** the system is also considered to be deadlocked if connection B has 5610** registered for an unlock-notify callback on the conclusion of connection 5611** C's transaction, where connection C is waiting on connection A. ^Any 5612** number of levels of indirection are allowed. 5613** 5614** <b>The "DROP TABLE" Exception</b> 5615** 5616** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 5617** always appropriate to call sqlite3_unlock_notify(). There is however, 5618** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 5619** SQLite checks if there are any currently executing SELECT statements 5620** that belong to the same connection. If there are, SQLITE_LOCKED is 5621** returned. In this case there is no "blocking connection", so invoking 5622** sqlite3_unlock_notify() results in the unlock-notify callback being 5623** invoked immediately. If the application then re-attempts the "DROP TABLE" 5624** or "DROP INDEX" query, an infinite loop might be the result. 5625** 5626** One way around this problem is to check the extended error code returned 5627** by an sqlite3_step() call. ^(If there is a blocking connection, then the 5628** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 5629** the special "DROP TABLE/INDEX" case, the extended error code is just 5630** SQLITE_LOCKED.)^ 5631*/ 5632SQLITE_API int sqlite3_unlock_notify( 5633 sqlite3 *pBlocked, /* Waiting connection */ 5634 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 5635 void *pNotifyArg /* Argument to pass to xNotify */ 5636); 5637 5638 5639/* 5640** CAPI3REF: String Comparison 5641** EXPERIMENTAL 5642** 5643** ^The [sqlite3_strnicmp()] API allows applications and extensions to 5644** compare the contents of two buffers containing UTF-8 strings in a 5645** case-indendent fashion, using the same definition of case independence 5646** that SQLite uses internally when comparing identifiers. 5647*/ 5648SQLITE_API int sqlite3_strnicmp(const char *, const char *, int); 5649 5650// Begin Android add 5651/* 5652** Android additional API. 5653** 5654** This function changes the default behavior of BEGIN to IMMEDIATE if called 5655** with immediate=1. 5656** Calling with immediate=0 will revert to DEFERRED. 5657*/ 5658int sqlite3_set_transaction_default_immediate(sqlite3*, int immediate); 5659// End Android add 5660 5661/* 5662** Undo the hack that converts floating point types to integer for 5663** builds on processors without floating point support. 5664*/ 5665#ifdef SQLITE_OMIT_FLOATING_POINT 5666# undef double 5667#endif 5668 5669#ifdef __cplusplus 5670} /* End of the 'extern "C"' block */ 5671#endif 5672#endif 5673 5674