/* ** 2001 September 15 ** ** The author disclaims copyright to this source code. In place of ** a legal notice, here is a blessing: ** ** May you do good and not evil. ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ************************************************************************* ** This header file defines the interface that the SQLite library ** presents to client programs. If a C-function, structure, datatype, ** or constant definition does not appear in this file, then it is ** not a published API of SQLite, is subject to change without ** notice, and should not be referenced by programs that use SQLite. ** ** Some of the definitions that are in this file are marked as ** "experimental". Experimental interfaces are normally new ** features recently added to SQLite. We do not anticipate changes ** to experimental interfaces but reserve the right to make minor changes ** if experience from use "in the wild" suggest such changes are prudent. ** ** The official C-language API documentation for SQLite is derived ** from comments in this file. This file is the authoritative source ** on how SQLite interfaces are suppose to operate. ** ** The name of this file under configuration management is "sqlite.h.in". ** The makefile makes some minor changes to this file (such as inserting ** the version number) and changes its name to "sqlite3.h" as ** part of the build process. */ #ifndef _SQLITE3_H_ #define _SQLITE3_H_ #include /* Needed for the definition of va_list */ /* ** Make sure we can call this stuff from C++. */ #ifdef __cplusplus extern "C" { #endif /* ** Add the ability to override 'extern' */ #ifndef SQLITE_EXTERN # define SQLITE_EXTERN extern #endif #ifndef SQLITE_API # define SQLITE_API #endif /* ** These no-op macros are used in front of interfaces to mark those ** interfaces as either deprecated or experimental. New applications ** should not use deprecated interfaces - they are support for backwards ** compatibility only. Application writers should be aware that ** experimental interfaces are subject to change in point releases. ** ** These macros used to resolve to various kinds of compiler magic that ** would generate warning messages when they were used. But that ** compiler magic ended up generating such a flurry of bug reports ** that we have taken it all out and gone back to using simple ** noop macros. */ #define SQLITE_DEPRECATED #define SQLITE_EXPERIMENTAL /* ** Ensure these symbols were not defined by some previous header file. */ #ifdef SQLITE_VERSION # undef SQLITE_VERSION #endif #ifdef SQLITE_VERSION_NUMBER # undef SQLITE_VERSION_NUMBER #endif /* ** CAPI3REF: Compile-Time Library Version Numbers ** ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header ** evaluates to a string literal that is the SQLite version in the ** format "X.Y.Z" where X is the major version number (always 3 for ** SQLite3) and Y is the minor version number and Z is the release number.)^ ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same ** numbers used in [SQLITE_VERSION].)^ ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also ** be larger than the release from which it is derived. Either Y will ** be held constant and Z will be incremented or else Y will be incremented ** and Z will be reset to zero. ** ** Since version 3.6.18, SQLite source code has been stored in the ** Fossil configuration management ** system. ^The SQLITE_SOURCE_ID macro evalutes to ** a string which identifies a particular check-in of SQLite ** within its configuration management system. ^The SQLITE_SOURCE_ID ** string contains the date and time of the check-in (UTC) and an SHA1 ** hash of the entire source tree. ** ** See also: [sqlite3_libversion()], ** [sqlite3_libversion_number()], [sqlite3_sourceid()], ** [sqlite_version()] and [sqlite_source_id()]. */ #define SQLITE_VERSION "3.7.0.1" #define SQLITE_VERSION_NUMBER 3007000 #define SQLITE_SOURCE_ID "2010-08-04 12:31:11 042a1abb030a0711386add7eb6e10832cc8b0f57" /* ** CAPI3REF: Run-Time Library Version Numbers ** KEYWORDS: sqlite3_version, sqlite3_sourceid ** ** These interfaces provide the same information as the [SQLITE_VERSION], ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros ** but are associated with the library instead of the header file. ^(Cautious ** programmers might include assert() statements in their application to ** verify that values returned by these interfaces match the macros in ** the header, and thus insure that the application is ** compiled with matching library and header files. ** ** 
** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
**
)^ ** ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] ** macro. ^The sqlite3_libversion() function returns a pointer to the ** to the sqlite3_version[] string constant. The sqlite3_libversion() ** function is provided for use in DLLs since DLL users usually do not have ** direct access to string constants within the DLL. ^The ** sqlite3_libversion_number() function returns an integer equal to ** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns ** a pointer to a string constant whose value is the same as the ** [SQLITE_SOURCE_ID] C preprocessor macro. ** ** See also: [sqlite_version()] and [sqlite_source_id()]. */ SQLITE_API SQLITE_EXTERN const char sqlite3_version[]; SQLITE_API const char *sqlite3_libversion(void); SQLITE_API const char *sqlite3_sourceid(void); SQLITE_API int sqlite3_libversion_number(void); /* ** CAPI3REF: Run-Time Library Compilation Options Diagnostics ** ** ^The sqlite3_compileoption_used() function returns 0 or 1 ** indicating whether the specified option was defined at ** compile time. ^The SQLITE_ prefix may be omitted from the ** option name passed to sqlite3_compileoption_used(). ** ** ^The sqlite3_compileoption_get() function allows interating ** over the list of options that were defined at compile time by ** returning the N-th compile time option string. ^If N is out of range, ** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ ** prefix is omitted from any strings returned by ** sqlite3_compileoption_get(). ** ** ^Support for the diagnostic functions sqlite3_compileoption_used() ** and sqlite3_compileoption_get() may be omitted by specifing the ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. ** ** See also: SQL functions [sqlite_compileoption_used()] and ** [sqlite_compileoption_get()] and the [compile_options pragma]. */ #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS SQLITE_API int sqlite3_compileoption_used(const char *zOptName); SQLITE_API const char *sqlite3_compileoption_get(int N); #endif /* ** CAPI3REF: Test To See If The Library Is Threadsafe ** ** ^The sqlite3_threadsafe() function returns zero if and only if ** SQLite was compiled mutexing code omitted due to the ** [SQLITE_THREADSAFE] compile-time option being set to 0. ** ** SQLite can be compiled with or without mutexes. When ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes ** are enabled and SQLite is threadsafe. When the ** [SQLITE_THREADSAFE] macro is 0, ** the mutexes are omitted. Without the mutexes, it is not safe ** to use SQLite concurrently from more than one thread. ** ** Enabling mutexes incurs a measurable performance penalty. ** So if speed is of utmost importance, it makes sense to disable ** the mutexes. But for maximum safety, mutexes should be enabled. ** ^The default behavior is for mutexes to be enabled. ** ** This interface can be used by an application to make sure that the ** version of SQLite that it is linking against was compiled with ** the desired setting of the [SQLITE_THREADSAFE] macro. ** ** This interface only reports on the compile-time mutex setting ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but ** can be fully or partially disabled using a call to [sqlite3_config()] ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], ** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the ** sqlite3_threadsafe() function shows only the compile-time setting of ** thread safety, not any run-time changes to that setting made by ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() ** is unchanged by calls to sqlite3_config().)^ ** ** See the [threading mode] documentation for additional information. */ SQLITE_API int sqlite3_threadsafe(void); /* ** CAPI3REF: Database Connection Handle ** KEYWORDS: {database connection} {database connections} ** ** Each open SQLite database is represented by a pointer to an instance of ** the opaque structure named "sqlite3". It is useful to think of an sqlite3 ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] ** is its destructor. There are many other interfaces (such as ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and ** [sqlite3_busy_timeout()] to name but three) that are methods on an ** sqlite3 object. */ typedef struct sqlite3 sqlite3; /* ** CAPI3REF: 64-Bit Integer Types ** KEYWORDS: sqlite_int64 sqlite_uint64 ** ** Because there is no cross-platform way to specify 64-bit integer types ** SQLite includes typedefs for 64-bit signed and unsigned integers. ** ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. ** The sqlite_int64 and sqlite_uint64 types are supported for backwards ** compatibility only. ** ** ^The sqlite3_int64 and sqlite_int64 types can store integer values ** between -9223372036854775808 and +9223372036854775807 inclusive. ^The ** sqlite3_uint64 and sqlite_uint64 types can store integer values ** between 0 and +18446744073709551615 inclusive. */ #ifdef SQLITE_INT64_TYPE typedef SQLITE_INT64_TYPE sqlite_int64; typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; #elif defined(_MSC_VER) || defined(__BORLANDC__) typedef __int64 sqlite_int64; typedef unsigned __int64 sqlite_uint64; #else typedef long long int sqlite_int64; typedef unsigned long long int sqlite_uint64; #endif typedef sqlite_int64 sqlite3_int64; typedef sqlite_uint64 sqlite3_uint64; /* ** If compiling for a processor that lacks floating point support, ** substitute integer for floating-point. */ #ifdef SQLITE_OMIT_FLOATING_POINT # define double sqlite3_int64 #endif /* ** CAPI3REF: Closing A Database Connection ** ** ^The sqlite3_close() routine is the destructor for the [sqlite3] object. ** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is ** successfullly destroyed and all associated resources are deallocated. ** ** Applications must [sqlite3_finalize | finalize] all [prepared statements] ** and [sqlite3_blob_close | close] all [BLOB handles] associated with ** the [sqlite3] object prior to attempting to close the object. ^If ** sqlite3_close() is called on a [database connection] that still has ** outstanding [prepared statements] or [BLOB handles], then it returns ** SQLITE_BUSY. ** ** ^If [sqlite3_close()] is invoked while a transaction is open, ** the transaction is automatically rolled back. ** ** The C parameter to [sqlite3_close(C)] must be either a NULL ** pointer or an [sqlite3] object pointer obtained ** from [sqlite3_open()], [sqlite3_open16()], or ** [sqlite3_open_v2()], and not previously closed. ** ^Calling sqlite3_close() with a NULL pointer argument is a ** harmless no-op. */ SQLITE_API int sqlite3_close(sqlite3 *); /* ** The type for a callback function. ** This is legacy and deprecated. It is included for historical ** compatibility and is not documented. */ typedef int (*sqlite3_callback)(void*,int,char**, char**); /* ** CAPI3REF: One-Step Query Execution Interface ** ** The sqlite3_exec() interface is a convenience wrapper around ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], ** that allows an application to run multiple statements of SQL ** without having to use a lot of C code. ** ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, ** semicolon-separate SQL statements passed into its 2nd argument, ** in the context of the [database connection] passed in as its 1st ** argument. ^If the callback function of the 3rd argument to ** sqlite3_exec() is not NULL, then it is invoked for each result row ** coming out of the evaluated SQL statements. ^The 4th argument to ** to sqlite3_exec() is relayed through to the 1st argument of each ** callback invocation. ^If the callback pointer to sqlite3_exec() ** is NULL, then no callback is ever invoked and result rows are ** ignored. ** ** ^If an error occurs while evaluating the SQL statements passed into ** sqlite3_exec(), then execution of the current statement stops and ** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() ** is not NULL then any error message is written into memory obtained ** from [sqlite3_malloc()] and passed back through the 5th parameter. ** To avoid memory leaks, the application should invoke [sqlite3_free()] ** on error message strings returned through the 5th parameter of ** of sqlite3_exec() after the error message string is no longer needed. ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to ** NULL before returning. ** ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() ** routine returns SQLITE_ABORT without invoking the callback again and ** without running any subsequent SQL statements. ** ** ^The 2nd argument to the sqlite3_exec() callback function is the ** number of columns in the result. ^The 3rd argument to the sqlite3_exec() ** callback is an array of pointers to strings obtained as if from ** [sqlite3_column_text()], one for each column. ^If an element of a ** result row is NULL then the corresponding string pointer for the ** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the ** sqlite3_exec() callback is an array of pointers to strings where each ** entry represents the name of corresponding result column as obtained ** from [sqlite3_column_name()]. ** ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer ** to an empty string, or a pointer that contains only whitespace and/or ** SQL comments, then no SQL statements are evaluated and the database ** is not changed. ** ** Restrictions: ** ** */ SQLITE_API int sqlite3_exec( sqlite3*, /* An open database */ const char *sql, /* SQL to be evaluated */ int (*callback)(void*,int,char**,char**), /* Callback function */ void *, /* 1st argument to callback */ char **errmsg /* Error msg written here */ ); /* ** CAPI3REF: Result Codes ** KEYWORDS: SQLITE_OK {error code} {error codes} ** KEYWORDS: {result code} {result codes} ** ** Many SQLite functions return an integer result code from the set shown ** here in order to indicates success or failure. ** ** New error codes may be added in future versions of SQLite. ** ** See also: [SQLITE_IOERR_READ | extended result codes] */ #define SQLITE_OK 0 /* Successful result */ /* beginning-of-error-codes */ #define SQLITE_ERROR 1 /* SQL error or missing database */ #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ #define SQLITE_PERM 3 /* Access permission denied */ #define SQLITE_ABORT 4 /* Callback routine requested an abort */ #define SQLITE_BUSY 5 /* The database file is locked */ #define SQLITE_LOCKED 6 /* A table in the database is locked */ #define SQLITE_NOMEM 7 /* A malloc() failed */ #define SQLITE_READONLY 8 /* Attempt to write a readonly database */ #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ #define SQLITE_CORRUPT 11 /* The database disk image is malformed */ #define SQLITE_NOTFOUND 12 /* NOT USED. Table or record not found */ #define SQLITE_FULL 13 /* Insertion failed because database is full */ #define SQLITE_CANTOPEN 14 /* Unable to open the database file */ #define SQLITE_PROTOCOL 15 /* Database lock protocol error */ #define SQLITE_EMPTY 16 /* Database is empty */ #define SQLITE_SCHEMA 17 /* The database schema changed */ #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ #define SQLITE_MISMATCH 20 /* Data type mismatch */ #define SQLITE_MISUSE 21 /* Library used incorrectly */ #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ #define SQLITE_AUTH 23 /* Authorization denied */ #define SQLITE_FORMAT 24 /* Auxiliary database format error */ #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ #define SQLITE_NOTADB 26 /* File opened that is not a database file */ #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ /* end-of-error-codes */ /* ** CAPI3REF: Extended Result Codes ** KEYWORDS: {extended error code} {extended error codes} ** KEYWORDS: {extended result code} {extended result codes} ** ** In its default configuration, SQLite API routines return one of 26 integer ** [SQLITE_OK | result codes]. However, experience has shown that many of ** these result codes are too coarse-grained. They do not provide as ** much information about problems as programmers might like. In an effort to ** address this, newer versions of SQLite (version 3.3.8 and later) include ** support for additional result codes that provide more detailed information ** about errors. The extended result codes are enabled or disabled ** on a per database connection basis using the ** [sqlite3_extended_result_codes()] API. ** ** Some of the available extended result codes are listed here. ** One may expect the number of extended result codes will be expand ** over time. Software that uses extended result codes should expect ** to see new result codes in future releases of SQLite. ** ** The SQLITE_OK result code will never be extended. It will always ** be exactly zero. */ #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) #define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) #define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) #define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) #define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) #define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) /* ** CAPI3REF: Flags For File Open Operations ** ** These bit values are intended for use in the ** 3rd parameter to the [sqlite3_open_v2()] interface and ** in the 4th parameter to the xOpen method of the ** [sqlite3_vfs] object. */ #define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ #define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ #define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ #define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ #define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ #define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ #define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ #define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ #define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ #define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ #define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ #define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ /* ** CAPI3REF: Device Characteristics ** ** The xDeviceCharacteristics method of the [sqlite3_io_methods] ** object returns an integer which is a vector of the these ** bit values expressing I/O characteristics of the mass storage ** device that holds the file that the [sqlite3_io_methods] ** refers to. ** ** The SQLITE_IOCAP_ATOMIC property means that all writes of ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values ** mean that writes of blocks that are nnn bytes in size and ** are aligned to an address which is an integer multiple of ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means ** that when data is appended to a file, the data is appended ** first then the size of the file is extended, never the other ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that ** information is written to disk in the same order as calls ** to xWrite(). */ #define SQLITE_IOCAP_ATOMIC 0x00000001 #define SQLITE_IOCAP_ATOMIC512 0x00000002 #define SQLITE_IOCAP_ATOMIC1K 0x00000004 #define SQLITE_IOCAP_ATOMIC2K 0x00000008 #define SQLITE_IOCAP_ATOMIC4K 0x00000010 #define SQLITE_IOCAP_ATOMIC8K 0x00000020 #define SQLITE_IOCAP_ATOMIC16K 0x00000040 #define SQLITE_IOCAP_ATOMIC32K 0x00000080 #define SQLITE_IOCAP_ATOMIC64K 0x00000100 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 /* ** CAPI3REF: File Locking Levels ** ** SQLite uses one of these integer values as the second ** argument to calls it makes to the xLock() and xUnlock() methods ** of an [sqlite3_io_methods] object. */ #define SQLITE_LOCK_NONE 0 #define SQLITE_LOCK_SHARED 1 #define SQLITE_LOCK_RESERVED 2 #define SQLITE_LOCK_PENDING 3 #define SQLITE_LOCK_EXCLUSIVE 4 /* ** CAPI3REF: Synchronization Type Flags ** ** When SQLite invokes the xSync() method of an ** [sqlite3_io_methods] object it uses a combination of ** these integer values as the second argument. ** ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the ** sync operation only needs to flush data to mass storage. Inode ** information need not be flushed. If the lower four bits of the flag ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. ** If the lower four bits equal SQLITE_SYNC_FULL, that means ** to use Mac OS X style fullsync instead of fsync(). */ #define SQLITE_SYNC_NORMAL 0x00002 #define SQLITE_SYNC_FULL 0x00003 #define SQLITE_SYNC_DATAONLY 0x00010 /* ** CAPI3REF: OS Interface Open File Handle ** ** An [sqlite3_file] object represents an open file in the ** [sqlite3_vfs | OS interface layer]. Individual OS interface ** implementations will ** want to subclass this object by appending additional fields ** for their own use. The pMethods entry is a pointer to an ** [sqlite3_io_methods] object that defines methods for performing ** I/O operations on the open file. */ typedef struct sqlite3_file sqlite3_file; struct sqlite3_file { const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ }; /* ** CAPI3REF: OS Interface File Virtual Methods Object ** ** Every file opened by the [sqlite3_vfs] xOpen method populates an ** [sqlite3_file] object (or, more commonly, a subclass of the ** [sqlite3_file] object) with a pointer to an instance of this object. ** This object defines the methods used to perform various operations ** against the open file represented by the [sqlite3_file] object. ** ** If the xOpen method sets the sqlite3_file.pMethods element ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method ** may be invoked even if the xOpen reported that it failed. The ** only way to prevent a call to xClose following a failed xOpen ** is for the xOpen to set the sqlite3_file.pMethods element to NULL. ** ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] ** flag may be ORed in to indicate that only the data of the file ** and not its inode needs to be synced. ** ** The integer values to xLock() and xUnlock() are one of ** ** xLock() increases the lock. xUnlock() decreases the lock. ** The xCheckReservedLock() method checks whether any database connection, ** either in this process or in some other process, is holding a RESERVED, ** PENDING, or EXCLUSIVE lock on the file. It returns true ** if such a lock exists and false otherwise. ** ** The xFileControl() method is a generic interface that allows custom ** VFS implementations to directly control an open file using the ** [sqlite3_file_control()] interface. The second "op" argument is an ** integer opcode. The third argument is a generic pointer intended to ** point to a structure that may contain arguments or space in which to ** write return values. Potential uses for xFileControl() might be ** functions to enable blocking locks with timeouts, to change the ** locking strategy (for example to use dot-file locks), to inquire ** about the status of a lock, or to break stale locks. The SQLite ** core reserves all opcodes less than 100 for its own use. ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. ** Applications that define a custom xFileControl method should use opcodes ** greater than 100 to avoid conflicts. ** ** The xSectorSize() method returns the sector size of the ** device that underlies the file. The sector size is the ** minimum write that can be performed without disturbing ** other bytes in the file. The xDeviceCharacteristics() ** method returns a bit vector describing behaviors of the ** underlying device: ** ** ** ** The SQLITE_IOCAP_ATOMIC property means that all writes of ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values ** mean that writes of blocks that are nnn bytes in size and ** are aligned to an address which is an integer multiple of ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means ** that when data is appended to a file, the data is appended ** first then the size of the file is extended, never the other ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that ** information is written to disk in the same order as calls ** to xWrite(). ** ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill ** in the unread portions of the buffer with zeros. A VFS that ** fails to zero-fill short reads might seem to work. However, ** failure to zero-fill short reads will eventually lead to ** database corruption. */ typedef struct sqlite3_io_methods sqlite3_io_methods; struct sqlite3_io_methods { int iVersion; int (*xClose)(sqlite3_file*); int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); int (*xSync)(sqlite3_file*, int flags); int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); int (*xLock)(sqlite3_file*, int); int (*xUnlock)(sqlite3_file*, int); int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); int (*xFileControl)(sqlite3_file*, int op, void *pArg); int (*xSectorSize)(sqlite3_file*); int (*xDeviceCharacteristics)(sqlite3_file*); /* Methods above are valid for version 1 */ int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); void (*xShmBarrier)(sqlite3_file*); int (*xShmUnmap)(sqlite3_file*, int deleteFlag); /* Methods above are valid for version 2 */ /* Additional methods may be added in future releases */ }; /* ** CAPI3REF: Standard File Control Opcodes ** ** These integer constants are opcodes for the xFileControl method ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] ** interface. ** ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This ** opcode causes the xFileControl method to write the current state of ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) ** into an integer that the pArg argument points to. This capability ** is used during testing and only needs to be supported when SQLITE_TEST ** is defined. ** ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS ** layer a hint of how large the database file will grow to be during the ** current transaction. This hint is not guaranteed to be accurate but it ** is often close. The underlying VFS might choose to preallocate database ** file space based on this hint in order to help writes to the database ** file run faster. */ #define SQLITE_FCNTL_LOCKSTATE 1 #define SQLITE_GET_LOCKPROXYFILE 2 #define SQLITE_SET_LOCKPROXYFILE 3 #define SQLITE_LAST_ERRNO 4 #define SQLITE_FCNTL_SIZE_HINT 5 /* ** CAPI3REF: Mutex Handle ** ** The mutex module within SQLite defines [sqlite3_mutex] to be an ** abstract type for a mutex object. The SQLite core never looks ** at the internal representation of an [sqlite3_mutex]. It only ** deals with pointers to the [sqlite3_mutex] object. ** ** Mutexes are created using [sqlite3_mutex_alloc()]. */ typedef struct sqlite3_mutex sqlite3_mutex; /* ** CAPI3REF: OS Interface Object ** ** An instance of the sqlite3_vfs object defines the interface between ** the SQLite core and the underlying operating system. The "vfs" ** in the name of the object stands for "virtual file system". ** ** The value of the iVersion field is initially 1 but may be larger in ** future versions of SQLite. Additional fields may be appended to this ** object when the iVersion value is increased. Note that the structure ** of the sqlite3_vfs object changes in the transaction between ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not ** modified. ** ** The szOsFile field is the size of the subclassed [sqlite3_file] ** structure used by this VFS. mxPathname is the maximum length of ** a pathname in this VFS. ** ** Registered sqlite3_vfs objects are kept on a linked list formed by ** the pNext pointer. The [sqlite3_vfs_register()] ** and [sqlite3_vfs_unregister()] interfaces manage this list ** in a thread-safe way. The [sqlite3_vfs_find()] interface ** searches the list. Neither the application code nor the VFS ** implementation should use the pNext pointer. ** ** The pNext field is the only field in the sqlite3_vfs ** structure that SQLite will ever modify. SQLite will only access ** or modify this field while holding a particular static mutex. ** The application should never modify anything within the sqlite3_vfs ** object once the object has been registered. ** ** The zName field holds the name of the VFS module. The name must ** be unique across all VFS modules. ** ** SQLite will guarantee that the zFilename parameter to xOpen ** is either a NULL pointer or string obtained ** from xFullPathname(). SQLite further guarantees that ** the string will be valid and unchanged until xClose() is ** called. Because of the previous sentence, ** the [sqlite3_file] can safely store a pointer to the ** filename if it needs to remember the filename for some reason. ** If the zFilename parameter is xOpen is a NULL pointer then xOpen ** must invent its own temporary name for the file. Whenever the ** xFilename parameter is NULL it will also be the case that the ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. ** ** The flags argument to xOpen() includes all bits set in ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] ** or [sqlite3_open16()] is used, then flags includes at least ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. ** If xOpen() opens a file read-only then it sets *pOutFlags to ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. ** ** SQLite will also add one of the following flags to the xOpen() ** call, depending on the object being opened: ** ** ** ** The file I/O implementation can use the object type flags to ** change the way it deals with files. For example, an application ** that does not care about crash recovery or rollback might make ** the open of a journal file a no-op. Writes to this journal would ** also be no-ops, and any attempt to read the journal would return ** SQLITE_IOERR. Or the implementation might recognize that a database ** file will be doing page-aligned sector reads and writes in a random ** order and set up its I/O subsystem accordingly. ** ** SQLite might also add one of the following flags to the xOpen method: ** ** ** ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be ** deleted when it is closed. The [SQLITE_OPEN_DELETEONCLOSE] ** will be set for TEMP databases, journals and for subjournals. ** ** The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction ** with the [SQLITE_OPEN_CREATE] flag, which are both directly ** analogous to the O_EXCL and O_CREAT flags of the POSIX open() ** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the ** SQLITE_OPEN_CREATE, is used to indicate that file should always ** be created, and that it is an error if it already exists. ** It is not used to indicate the file should be opened ** for exclusive access. ** ** At least szOsFile bytes of memory are allocated by SQLite ** to hold the [sqlite3_file] structure passed as the third ** argument to xOpen. The xOpen method does not have to ** allocate the structure; it should just fill it in. Note that ** the xOpen method must set the sqlite3_file.pMethods to either ** a valid [sqlite3_io_methods] object or to NULL. xOpen must do ** this even if the open fails. SQLite expects that the sqlite3_file.pMethods ** element will be valid after xOpen returns regardless of the success ** or failure of the xOpen call. ** ** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] ** to test whether a file is at least readable. The file can be a ** directory. ** ** SQLite will always allocate at least mxPathname+1 bytes for the ** output buffer xFullPathname. The exact size of the output buffer ** is also passed as a parameter to both methods. If the output buffer ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is ** handled as a fatal error by SQLite, vfs implementations should endeavor ** to prevent this by setting mxPathname to a sufficiently large value. ** ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() ** interfaces are not strictly a part of the filesystem, but they are ** included in the VFS structure for completeness. ** The xRandomness() function attempts to return nBytes bytes ** of good-quality randomness into zOut. The return value is ** the actual number of bytes of randomness obtained. ** The xSleep() method causes the calling thread to sleep for at ** least the number of microseconds given. The xCurrentTime() ** method returns a Julian Day Number for the current date and time as ** a floating point value. ** The xCurrentTimeInt64() method returns, as an integer, the Julian ** Day Number multipled by 86400000 (the number of milliseconds in ** a 24-hour day). ** ^SQLite will use the xCurrentTimeInt64() method to get the current ** date and time if that method is available (if iVersion is 2 or ** greater and the function pointer is not NULL) and will fall back ** to xCurrentTime() if xCurrentTimeInt64() is unavailable. */ typedef struct sqlite3_vfs sqlite3_vfs; struct sqlite3_vfs { int iVersion; /* Structure version number (currently 2) */ int szOsFile; /* Size of subclassed sqlite3_file */ int mxPathname; /* Maximum file pathname length */ sqlite3_vfs *pNext; /* Next registered VFS */ const char *zName; /* Name of this virtual file system */ void *pAppData; /* Pointer to application-specific data */ int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, int flags, int *pOutFlags); int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); void (*xDlClose)(sqlite3_vfs*, void*); int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); int (*xSleep)(sqlite3_vfs*, int microseconds); int (*xCurrentTime)(sqlite3_vfs*, double*); int (*xGetLastError)(sqlite3_vfs*, int, char *); /* ** The methods above are in version 1 of the sqlite_vfs object ** definition. Those that follow are added in version 2 or later */ int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); /* ** The methods above are in versions 1 and 2 of the sqlite_vfs object. ** New fields may be appended in figure versions. The iVersion ** value will increment whenever this happens. */ }; /* ** CAPI3REF: Flags for the xAccess VFS method ** ** These integer constants can be used as the third parameter to ** the xAccess method of an [sqlite3_vfs] object. They determine ** what kind of permissions the xAccess method is looking for. ** With SQLITE_ACCESS_EXISTS, the xAccess method ** simply checks whether the file exists. ** With SQLITE_ACCESS_READWRITE, the xAccess method ** checks whether the named directory is both readable and writable ** (in other words, if files can be added, removed, and renamed within ** the directory). ** The SQLITE_ACCESS_READWRITE constant is currently used only by the ** [temp_store_directory pragma], though this could change in a future ** release of SQLite. ** With SQLITE_ACCESS_READ, the xAccess method ** checks whether the file is readable. The SQLITE_ACCESS_READ constant is ** currently unused, though it might be used in a future release of ** SQLite. */ #define SQLITE_ACCESS_EXISTS 0 #define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ #define SQLITE_ACCESS_READ 2 /* Unused */ /* ** CAPI3REF: Flags for the xShmLock VFS method ** ** These integer constants define the various locking operations ** allowed by the xShmLock method of [sqlite3_io_methods]. The ** following are the only legal combinations of flags to the ** xShmLock method: ** ** ** ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as ** was given no the corresponding lock. ** ** The xShmLock method can transition between unlocked and SHARED or ** between unlocked and EXCLUSIVE. It cannot transition between SHARED ** and EXCLUSIVE. */ #define SQLITE_SHM_UNLOCK 1 #define SQLITE_SHM_LOCK 2 #define SQLITE_SHM_SHARED 4 #define SQLITE_SHM_EXCLUSIVE 8 /* ** CAPI3REF: Maximum xShmLock index ** ** The xShmLock method on [sqlite3_io_methods] may use values ** between 0 and this upper bound as its "offset" argument. ** The SQLite core will never attempt to acquire or release a ** lock outside of this range */ #define SQLITE_SHM_NLOCK 8 /* ** CAPI3REF: Initialize The SQLite Library ** ** ^The sqlite3_initialize() routine initializes the ** SQLite library. ^The sqlite3_shutdown() routine ** deallocates any resources that were allocated by sqlite3_initialize(). ** These routines are designed to aid in process initialization and ** shutdown on embedded systems. Workstation applications using ** SQLite normally do not need to invoke either of these routines. ** ** A call to sqlite3_initialize() is an "effective" call if it is ** the first time sqlite3_initialize() is invoked during the lifetime of ** the process, or if it is the first time sqlite3_initialize() is invoked ** following a call to sqlite3_shutdown(). ^(Only an effective call ** of sqlite3_initialize() does any initialization. All other calls ** are harmless no-ops.)^ ** ** A call to sqlite3_shutdown() is an "effective" call if it is the first ** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only ** an effective call to sqlite3_shutdown() does any deinitialization. ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ ** ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() ** is not. The sqlite3_shutdown() interface must only be called from a ** single thread. All open [database connections] must be closed and all ** other SQLite resources must be deallocated prior to invoking ** sqlite3_shutdown(). ** ** Among other things, ^sqlite3_initialize() will invoke ** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() ** will invoke sqlite3_os_end(). ** ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. ** ^If for some reason, sqlite3_initialize() is unable to initialize ** the library (perhaps it is unable to allocate a needed resource such ** as a mutex) it returns an [error code] other than [SQLITE_OK]. ** ** ^The sqlite3_initialize() routine is called internally by many other ** SQLite interfaces so that an application usually does not need to ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] ** calls sqlite3_initialize() so the SQLite library will be automatically ** initialized when [sqlite3_open()] is called if it has not be initialized ** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] ** compile-time option, then the automatic calls to sqlite3_initialize() ** are omitted and the application must call sqlite3_initialize() directly ** prior to using any other SQLite interface. For maximum portability, ** it is recommended that applications always invoke sqlite3_initialize() ** directly prior to using any other SQLite interface. Future releases ** of SQLite may require this. In other words, the behavior exhibited ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the ** default behavior in some future release of SQLite. ** ** The sqlite3_os_init() routine does operating-system specific ** initialization of the SQLite library. The sqlite3_os_end() ** routine undoes the effect of sqlite3_os_init(). Typical tasks ** performed by these routines include allocation or deallocation ** of static resources, initialization of global variables, ** setting up a default [sqlite3_vfs] module, or setting up ** a default configuration using [sqlite3_config()]. ** ** The application should never invoke either sqlite3_os_init() ** or sqlite3_os_end() directly. The application should only invoke ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() ** interface is called automatically by sqlite3_initialize() and ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate ** implementations for sqlite3_os_init() and sqlite3_os_end() ** are built into SQLite when it is compiled for Unix, Windows, or OS/2. ** When [custom builds | built for other platforms] ** (using the [SQLITE_OS_OTHER=1] compile-time ** option) the application must supply a suitable implementation for ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied ** implementation of sqlite3_os_init() or sqlite3_os_end() ** must return [SQLITE_OK] on success and some other [error code] upon ** failure. */ SQLITE_API int sqlite3_initialize(void); SQLITE_API int sqlite3_shutdown(void); SQLITE_API int sqlite3_os_init(void); SQLITE_API int sqlite3_os_end(void); /* ** CAPI3REF: Configuring The SQLite Library ** ** The sqlite3_config() interface is used to make global configuration ** changes to SQLite in order to tune SQLite to the specific needs of ** the application. The default configuration is recommended for most ** applications and so this routine is usually not necessary. It is ** provided to support rare applications with unusual needs. ** ** The sqlite3_config() interface is not threadsafe. The application ** must insure that no other SQLite interfaces are invoked by other ** threads while sqlite3_config() is running. Furthermore, sqlite3_config() ** may only be invoked prior to library initialization using ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. ** Note, however, that ^sqlite3_config() can be called as part of the ** implementation of an application-defined [sqlite3_os_init()]. ** ** The first argument to sqlite3_config() is an integer ** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines ** what property of SQLite is to be configured. Subsequent arguments ** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option] ** in the first argument. ** ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. ** ^If the option is unknown or SQLite is unable to set the option ** then this routine returns a non-zero [error code]. */ SQLITE_API int sqlite3_config(int, ...); /* ** CAPI3REF: Configure database connections ** ** The sqlite3_db_config() interface is used to make configuration ** changes to a [database connection]. The interface is similar to ** [sqlite3_config()] except that the changes apply to a single ** [database connection] (specified in the first argument). The ** sqlite3_db_config() interface should only be used immediately after ** the database connection is created using [sqlite3_open()], ** [sqlite3_open16()], or [sqlite3_open_v2()]. ** ** The second argument to sqlite3_db_config(D,V,...) is the ** configuration verb - an integer code that indicates what ** aspect of the [database connection] is being configured. ** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE]. ** New verbs are likely to be added in future releases of SQLite. ** Additional arguments depend on the verb. ** ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if ** the call is considered successful. */ SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...); /* ** CAPI3REF: Memory Allocation Routines ** ** An instance of this object defines the interface between SQLite ** and low-level memory allocation routines. ** ** This object is used in only one place in the SQLite interface. ** A pointer to an instance of this object is the argument to ** [sqlite3_config()] when the configuration option is ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. ** By creating an instance of this object ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) ** during configuration, an application can specify an alternative ** memory allocation subsystem for SQLite to use for all of its ** dynamic memory needs. ** ** Note that SQLite comes with several [built-in memory allocators] ** that are perfectly adequate for the overwhelming majority of applications ** and that this object is only useful to a tiny minority of applications ** with specialized memory allocation requirements. This object is ** also used during testing of SQLite in order to specify an alternative ** memory allocator that simulates memory out-of-memory conditions in ** order to verify that SQLite recovers gracefully from such ** conditions. ** ** The xMalloc and xFree methods must work like the ** malloc() and free() functions from the standard C library. ** The xRealloc method must work like realloc() from the standard C library ** with the exception that if the second argument to xRealloc is zero, ** xRealloc must be a no-op - it must not perform any allocation or ** deallocation. ^SQLite guarantees that the second argument to ** xRealloc is always a value returned by a prior call to xRoundup. ** And so in cases where xRoundup always returns a positive number, ** xRealloc can perform exactly as the standard library realloc() and ** still be in compliance with this specification. ** ** xSize should return the allocated size of a memory allocation ** previously obtained from xMalloc or xRealloc. The allocated size ** is always at least as big as the requested size but may be larger. ** ** The xRoundup method returns what would be the allocated size of ** a memory allocation given a particular requested size. Most memory ** allocators round up memory allocations at least to the next multiple ** of 8. Some allocators round up to a larger multiple or to a power of 2. ** Every memory allocation request coming in through [sqlite3_malloc()] ** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, ** that causes the corresponding memory allocation to fail. ** ** The xInit method initializes the memory allocator. (For example, ** it might allocate any require mutexes or initialize internal data ** structures. The xShutdown method is invoked (indirectly) by ** [sqlite3_shutdown()] and should deallocate any resources acquired ** by xInit. The pAppData pointer is used as the only parameter to ** xInit and xShutdown. ** ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes ** the xInit method, so the xInit method need not be threadsafe. The ** xShutdown method is only called from [sqlite3_shutdown()] so it does ** not need to be threadsafe either. For all other methods, SQLite ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which ** it is by default) and so the methods are automatically serialized. ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other ** methods must be threadsafe or else make their own arrangements for ** serialization. ** ** SQLite will never invoke xInit() more than once without an intervening ** call to xShutdown(). */ typedef struct sqlite3_mem_methods sqlite3_mem_methods; struct sqlite3_mem_methods { void *(*xMalloc)(int); /* Memory allocation function */ void (*xFree)(void*); /* Free a prior allocation */ void *(*xRealloc)(void*,int); /* Resize an allocation */ int (*xSize)(void*); /* Return the size of an allocation */ int (*xRoundup)(int); /* Round up request size to allocation size */ int (*xInit)(void*); /* Initialize the memory allocator */ void (*xShutdown)(void*); /* Deinitialize the memory allocator */ void *pAppData; /* Argument to xInit() and xShutdown() */ }; /* ** CAPI3REF: Configuration Options ** ** These constants are the available integer configuration options that ** can be passed as the first argument to the [sqlite3_config()] interface. ** ** New configuration options may be added in future releases of SQLite. ** Existing configuration options might be discontinued. Applications ** should check the return code from [sqlite3_config()] to make sure that ** the call worked. The [sqlite3_config()] interface will return a ** non-zero [error code] if a discontinued or unsupported configuration option ** is invoked. ** **
**
SQLITE_CONFIG_SINGLETHREAD
**
There are no arguments to this option. ^This option sets the ** [threading mode] to Single-thread. In other words, it disables ** all mutexing and puts SQLite into a mode where it can only be used ** by a single thread. ^If SQLite is compiled with ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then ** it is not possible to change the [threading mode] from its default ** value of Single-thread and so [sqlite3_config()] will return ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD ** configuration option.
** **
SQLITE_CONFIG_MULTITHREAD
**
There are no arguments to this option. ^This option sets the ** [threading mode] to Multi-thread. In other words, it disables ** mutexing on [database connection] and [prepared statement] objects. ** The application is responsible for serializing access to ** [database connections] and [prepared statements]. But other mutexes ** are enabled so that SQLite will be safe to use in a multi-threaded ** environment as long as no two threads attempt to use the same ** [database connection] at the same time. ^If SQLite is compiled with ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then ** it is not possible to set the Multi-thread [threading mode] and ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the ** SQLITE_CONFIG_MULTITHREAD configuration option.
** **
SQLITE_CONFIG_SERIALIZED
**
There are no arguments to this option. ^This option sets the ** [threading mode] to Serialized. In other words, this option enables ** all mutexes including the recursive ** mutexes on [database connection] and [prepared statement] objects. ** In this mode (which is the default when SQLite is compiled with ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access ** to [database connections] and [prepared statements] so that the ** application is free to use the same [database connection] or the ** same [prepared statement] in different threads at the same time. ** ^If SQLite is compiled with ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then ** it is not possible to set the Serialized [threading mode] and ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the ** SQLITE_CONFIG_SERIALIZED configuration option.
** **
SQLITE_CONFIG_MALLOC
**
^(This option takes a single argument which is a pointer to an ** instance of the [sqlite3_mem_methods] structure. The argument specifies ** alternative low-level memory allocation routines to be used in place of ** the memory allocation routines built into SQLite.)^ ^SQLite makes ** its own private copy of the content of the [sqlite3_mem_methods] structure ** before the [sqlite3_config()] call returns.
** **
SQLITE_CONFIG_GETMALLOC
**
^(This option takes a single argument which is a pointer to an ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] ** structure is filled with the currently defined memory allocation routines.)^ ** This option can be used to overload the default memory allocation ** routines with a wrapper that simulations memory allocation failure or ** tracks memory usage, for example.
** **
SQLITE_CONFIG_MEMSTATUS
**
^This option takes single argument of type int, interpreted as a ** boolean, which enables or disables the collection of memory allocation ** statistics. ^(When memory allocation statistics are disabled, the ** following SQLite interfaces become non-operational: **
    **
  • [sqlite3_memory_used()] **
  • [sqlite3_memory_highwater()] **
  • [sqlite3_soft_heap_limit()] **
  • [sqlite3_status()] **
)^ ** ^Memory allocation statistics are enabled by default unless SQLite is ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory ** allocation statistics are disabled by default. **
** **
SQLITE_CONFIG_SCRATCH
**
^This option specifies a static memory buffer that SQLite can use for ** scratch memory. There are three arguments: A pointer an 8-byte ** aligned memory buffer from which the scrach allocations will be ** drawn, the size of each scratch allocation (sz), ** and the maximum number of scratch allocations (N). The sz ** argument must be a multiple of 16. The sz parameter should be a few bytes ** larger than the actual scratch space required due to internal overhead. ** The first argument must be a pointer to an 8-byte aligned buffer ** of at least sz*N bytes of memory. ** ^SQLite will use no more than one scratch buffer per thread. So ** N should be set to the expected maximum number of threads. ^SQLite will ** never require a scratch buffer that is more than 6 times the database ** page size. ^If SQLite needs needs additional scratch memory beyond ** what is provided by this configuration option, then ** [sqlite3_malloc()] will be used to obtain the memory needed.
** **
SQLITE_CONFIG_PAGECACHE
**
^This option specifies a static memory buffer that SQLite can use for ** the database page cache with the default page cache implemenation. ** This configuration should not be used if an application-define page ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option. ** There are three arguments to this option: A pointer to 8-byte aligned ** memory, the size of each page buffer (sz), and the number of pages (N). ** The sz argument should be the size of the largest database page ** (a power of two between 512 and 32768) plus a little extra for each ** page header. ^The page header size is 20 to 40 bytes depending on ** the host architecture. ^It is harmless, apart from the wasted memory, ** to make sz a little too large. The first ** argument should point to an allocation of at least sz*N bytes of memory. ** ^SQLite will use the memory provided by the first argument to satisfy its ** memory needs for the first N pages that it adds to cache. ^If additional ** page cache memory is needed beyond what is provided by this option, then ** SQLite goes to [sqlite3_malloc()] for the additional storage space. ** ^The implementation might use one or more of the N buffers to hold ** memory accounting information. The pointer in the first argument must ** be aligned to an 8-byte boundary or subsequent behavior of SQLite ** will be undefined.
** **
SQLITE_CONFIG_HEAP
**
^This option specifies a static memory buffer that SQLite will use ** for all of its dynamic memory allocation needs beyond those provided ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. ** There are three arguments: An 8-byte aligned pointer to the memory, ** the number of bytes in the memory buffer, and the minimum allocation size. ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts ** to using its default memory allocator (the system malloc() implementation), ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory ** allocator is engaged to handle all of SQLites memory allocation needs. ** The first pointer (the memory pointer) must be aligned to an 8-byte ** boundary or subsequent behavior of SQLite will be undefined.
** **
SQLITE_CONFIG_MUTEX
**
^(This option takes a single argument which is a pointer to an ** instance of the [sqlite3_mutex_methods] structure. The argument specifies ** alternative low-level mutex routines to be used in place ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the ** content of the [sqlite3_mutex_methods] structure before the call to ** [sqlite3_config()] returns. ^If SQLite is compiled with ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then ** the entire mutexing subsystem is omitted from the build and hence calls to ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will ** return [SQLITE_ERROR].
** **
SQLITE_CONFIG_GETMUTEX
**
^(This option takes a single argument which is a pointer to an ** instance of the [sqlite3_mutex_methods] structure. The ** [sqlite3_mutex_methods] ** structure is filled with the currently defined mutex routines.)^ ** This option can be used to overload the default mutex allocation ** routines with a wrapper used to track mutex usage for performance ** profiling or testing, for example. ^If SQLite is compiled with ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then ** the entire mutexing subsystem is omitted from the build and hence calls to ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will ** return [SQLITE_ERROR].
** **
SQLITE_CONFIG_LOOKASIDE
**
^(This option takes two arguments that determine the default ** memory allocation for the lookaside memory allocator on each ** [database connection]. The first argument is the ** size of each lookaside buffer slot and the second is the number of ** slots allocated to each database connection.)^ ^(This option sets the ** default lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] ** verb to [sqlite3_db_config()] can be used to change the lookaside ** configuration on individual connections.)^
** **
SQLITE_CONFIG_PCACHE
**
^(This option takes a single argument which is a pointer to ** an [sqlite3_pcache_methods] object. This object specifies the interface ** to a custom page cache implementation.)^ ^SQLite makes a copy of the ** object and uses it for page cache memory allocations.
** **
SQLITE_CONFIG_GETPCACHE
**
^(This option takes a single argument which is a pointer to an ** [sqlite3_pcache_methods] object. SQLite copies of the current ** page cache implementation into that object.)^
** **
SQLITE_CONFIG_LOG
**
^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a ** function with a call signature of void(*)(void*,int,const char*), ** and a pointer to void. ^If the function pointer is not NULL, it is ** invoked by [sqlite3_log()] to process each logging event. ^If the ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is ** passed through as the first parameter to the application-defined logger ** function whenever that function is invoked. ^The second parameter to ** the logger function is a copy of the first parameter to the corresponding ** [sqlite3_log()] call and is intended to be a [result code] or an ** [extended result code]. ^The third parameter passed to the logger is ** log message after formatting via [sqlite3_snprintf()]. ** The SQLite logging interface is not reentrant; the logger function ** supplied by the application must not invoke any SQLite interface. ** In a multi-threaded application, the application-defined logger ** function must be threadsafe.
** **
*/ #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ #define SQLITE_CONFIG_SERIALIZED 3 /* nil */ #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ #define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */ #define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */ #define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ /* ** CAPI3REF: Database Connection Configuration Options ** ** These constants are the available integer configuration options that ** can be passed as the second argument to the [sqlite3_db_config()] interface. ** ** New configuration options may be added in future releases of SQLite. ** Existing configuration options might be discontinued. Applications ** should check the return code from [sqlite3_db_config()] to make sure that ** the call worked. ^The [sqlite3_db_config()] interface will return a ** non-zero [error code] if a discontinued or unsupported configuration option ** is invoked. ** **
**
SQLITE_DBCONFIG_LOOKASIDE
**
^This option takes three additional arguments that determine the ** [lookaside memory allocator] configuration for the [database connection]. ** ^The first argument (the third parameter to [sqlite3_db_config()] is a ** pointer to an memory buffer to use for lookaside memory. ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb ** may be NULL in which case SQLite will allocate the ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the ** size of each lookaside buffer slot. ^The third argument is the number of ** slots. The size of the buffer in the first argument must be greater than ** or equal to the product of the second and third arguments. The buffer ** must be aligned to an 8-byte boundary. ^If the second argument to ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally ** rounded down to the next smaller ** multiple of 8. See also: [SQLITE_CONFIG_LOOKASIDE]
** **
*/ #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ /* ** CAPI3REF: Enable Or Disable Extended Result Codes ** ** ^The sqlite3_extended_result_codes() routine enables or disables the ** [extended result codes] feature of SQLite. ^The extended result ** codes are disabled by default for historical compatibility. */ SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff); /* ** CAPI3REF: Last Insert Rowid ** ** ^Each entry in an SQLite table has a unique 64-bit signed ** integer key called the [ROWID | "rowid"]. ^The rowid is always available ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those ** names are not also used by explicitly declared columns. ^If ** the table has a column of type [INTEGER PRIMARY KEY] then that column ** is another alias for the rowid. ** ** ^This routine returns the [rowid] of the most recent ** successful [INSERT] into the database from the [database connection] ** in the first argument. ^If no successful [INSERT]s ** have ever occurred on that database connection, zero is returned. ** ** ^(If an [INSERT] occurs within a trigger, then the [rowid] of the inserted ** row is returned by this routine as long as the trigger is running. ** But once the trigger terminates, the value returned by this routine ** reverts to the last value inserted before the trigger fired.)^ ** ** ^An [INSERT] that fails due to a constraint violation is not a ** successful [INSERT] and does not change the value returned by this ** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, ** and INSERT OR ABORT make no changes to the return value of this ** routine when their insertion fails. ^(When INSERT OR REPLACE ** encounters a constraint violation, it does not fail. The ** INSERT continues to completion after deleting rows that caused ** the constraint problem so INSERT OR REPLACE will always change ** the return value of this interface.)^ ** ** ^For the purposes of this routine, an [INSERT] is considered to ** be successful even if it is subsequently rolled back. ** ** This function is accessible to SQL statements via the ** [last_insert_rowid() SQL function]. ** ** If a separate thread performs a new [INSERT] on the same ** database connection while the [sqlite3_last_insert_rowid()] ** function is running and thus changes the last insert [rowid], ** then the value returned by [sqlite3_last_insert_rowid()] is ** unpredictable and might not equal either the old or the new ** last insert [rowid]. */ SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); /* ** CAPI3REF: Count The Number Of Rows Modified ** ** ^This function returns the number of database rows that were changed ** or inserted or deleted by the most recently completed SQL statement ** on the [database connection] specified by the first parameter. ** ^(Only changes that are directly specified by the [INSERT], [UPDATE], ** or [DELETE] statement are counted. Auxiliary changes caused by ** triggers or [foreign key actions] are not counted.)^ Use the ** [sqlite3_total_changes()] function to find the total number of changes ** including changes caused by triggers and foreign key actions. ** ** ^Changes to a view that are simulated by an [INSTEAD OF trigger] ** are not counted. Only real table changes are counted. ** ** ^(A "row change" is a change to a single row of a single table ** caused by an INSERT, DELETE, or UPDATE statement. Rows that ** are changed as side effects of [REPLACE] constraint resolution, ** rollback, ABORT processing, [DROP TABLE], or by any other ** mechanisms do not count as direct row changes.)^ ** ** A "trigger context" is a scope of execution that begins and ** ends with the script of a [CREATE TRIGGER | trigger]. ** Most SQL statements are ** evaluated outside of any trigger. This is the "top level" ** trigger context. If a trigger fires from the top level, a ** new trigger context is entered for the duration of that one ** trigger. Subtriggers create subcontexts for their duration. ** ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does ** not create a new trigger context. ** ** ^This function returns the number of direct row changes in the ** most recent INSERT, UPDATE, or DELETE statement within the same ** trigger context. ** ** ^Thus, when called from the top level, this function returns the ** number of changes in the most recent INSERT, UPDATE, or DELETE ** that also occurred at the top level. ^(Within the body of a trigger, ** the sqlite3_changes() interface can be called to find the number of ** changes in the most recently completed INSERT, UPDATE, or DELETE ** statement within the body of the same trigger. ** However, the number returned does not include changes ** caused by subtriggers since those have their own context.)^ ** ** See also the [sqlite3_total_changes()] interface, the ** [count_changes pragma], and the [changes() SQL function]. ** ** If a separate thread makes changes on the same database connection ** while [sqlite3_changes()] is running then the value returned ** is unpredictable and not meaningful. */ SQLITE_API int sqlite3_changes(sqlite3*); /* ** CAPI3REF: Total Number Of Rows Modified ** ** ^This function returns the number of row changes caused by [INSERT], ** [UPDATE] or [DELETE] statements since the [database connection] was opened. ** ^(The count returned by sqlite3_total_changes() includes all changes ** from all [CREATE TRIGGER | trigger] contexts and changes made by ** [foreign key actions]. However, ** the count does not include changes used to implement [REPLACE] constraints, ** do rollbacks or ABORT processing, or [DROP TABLE] processing. The ** count does not include rows of views that fire an [INSTEAD OF trigger], ** though if the INSTEAD OF trigger makes changes of its own, those changes ** are counted.)^ ** ^The sqlite3_total_changes() function counts the changes as soon as ** the statement that makes them is completed (when the statement handle ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). ** ** See also the [sqlite3_changes()] interface, the ** [count_changes pragma], and the [total_changes() SQL function]. ** ** If a separate thread makes changes on the same database connection ** while [sqlite3_total_changes()] is running then the value ** returned is unpredictable and not meaningful. */ SQLITE_API int sqlite3_total_changes(sqlite3*); /* ** CAPI3REF: Interrupt A Long-Running Query ** ** ^This function causes any pending database operation to abort and ** return at its earliest opportunity. This routine is typically ** called in response to a user action such as pressing "Cancel" ** or Ctrl-C where the user wants a long query operation to halt ** immediately. ** ** ^It is safe to call this routine from a thread different from the ** thread that is currently running the database operation. But it ** is not safe to call this routine with a [database connection] that ** is closed or might close before sqlite3_interrupt() returns. ** ** ^If an SQL operation is very nearly finished at the time when ** sqlite3_interrupt() is called, then it might not have an opportunity ** to be interrupted and might continue to completion. ** ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE ** that is inside an explicit transaction, then the entire transaction ** will be rolled back automatically. ** ** ^The sqlite3_interrupt(D) call is in effect until all currently running ** SQL statements on [database connection] D complete. ^Any new SQL statements ** that are started after the sqlite3_interrupt() call and before the ** running statements reaches zero are interrupted as if they had been ** running prior to the sqlite3_interrupt() call. ^New SQL statements ** that are started after the running statement count reaches zero are ** not effected by the sqlite3_interrupt(). ** ^A call to sqlite3_interrupt(D) that occurs when there are no running ** SQL statements is a no-op and has no effect on SQL statements ** that are started after the sqlite3_interrupt() call returns. ** ** If the database connection closes while [sqlite3_interrupt()] ** is running then bad things will likely happen. */ SQLITE_API void sqlite3_interrupt(sqlite3*); /* ** CAPI3REF: Determine If An SQL Statement Is Complete ** ** These routines are useful during command-line input to determine if the ** currently entered text seems to form a complete SQL statement or ** if additional input is needed before sending the text into ** SQLite for parsing. ^These routines return 1 if the input string ** appears to be a complete SQL statement. ^A statement is judged to be ** complete if it ends with a semicolon token and is not a prefix of a ** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within ** string literals or quoted identifier names or comments are not ** independent tokens (they are part of the token in which they are ** embedded) and thus do not count as a statement terminator. ^Whitespace ** and comments that follow the final semicolon are ignored. ** ** ^These routines return 0 if the statement is incomplete. ^If a ** memory allocation fails, then SQLITE_NOMEM is returned. ** ** ^These routines do not parse the SQL statements thus ** will not detect syntactically incorrect SQL. ** ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked ** automatically by sqlite3_complete16(). If that initialization fails, ** then the return value from sqlite3_complete16() will be non-zero ** regardless of whether or not the input SQL is complete.)^ ** ** The input to [sqlite3_complete()] must be a zero-terminated ** UTF-8 string. ** ** The input to [sqlite3_complete16()] must be a zero-terminated ** UTF-16 string in native byte order. */ SQLITE_API int sqlite3_complete(const char *sql); SQLITE_API int sqlite3_complete16(const void *sql); /* ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors ** ** ^This routine sets a callback function that might be invoked whenever ** an attempt is made to open a database table that another thread ** or process has locked. ** ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] ** is returned immediately upon encountering the lock. ^If the busy callback ** is not NULL, then the callback might be invoked with two arguments. ** ** ^The first argument to the busy handler is a copy of the void* pointer which ** is the third argument to sqlite3_busy_handler(). ^The second argument to ** the busy handler callback is the number of times that the busy handler has ** been invoked for this locking event. ^If the ** busy callback returns 0, then no additional attempts are made to ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. ** ^If the callback returns non-zero, then another attempt ** is made to open the database for reading and the cycle repeats. ** ** The presence of a busy handler does not guarantee that it will be invoked ** when there is lock contention. ^If SQLite determines that invoking the busy ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. ** Consider a scenario where one process is holding a read lock that ** it is trying to promote to a reserved lock and ** a second process is holding a reserved lock that it is trying ** to promote to an exclusive lock. The first process cannot proceed ** because it is blocked by the second and the second process cannot ** proceed because it is blocked by the first. If both processes ** invoke the busy handlers, neither will make any progress. Therefore, ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this ** will induce the first process to release its read lock and allow ** the second process to proceed. ** ** ^The default busy callback is NULL. ** ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] ** when SQLite is in the middle of a large transaction where all the ** changes will not fit into the in-memory cache. SQLite will ** already hold a RESERVED lock on the database file, but it needs ** to promote this lock to EXCLUSIVE so that it can spill cache ** pages into the database file without harm to concurrent ** readers. ^If it is unable to promote the lock, then the in-memory ** cache will be left in an inconsistent state and so the error ** code is promoted from the relatively benign [SQLITE_BUSY] to ** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion ** forces an automatic rollback of the changes. See the ** ** CorruptionFollowingBusyError wiki page for a discussion of why ** this is important. ** ** ^(There can only be a single busy handler defined for each ** [database connection]. Setting a new busy handler clears any ** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] ** will also set or clear the busy handler. ** ** The busy callback should not take any actions which modify the ** database connection that invoked the busy handler. Any such actions ** result in undefined behavior. ** ** A busy handler must not close the database connection ** or [prepared statement] that invoked the busy handler. */ SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); /* ** CAPI3REF: Set A Busy Timeout ** ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps ** for a specified amount of time when a table is locked. ^The handler ** will sleep multiple times until at least "ms" milliseconds of sleeping ** have accumulated. ^After at least "ms" milliseconds of sleeping, ** the handler returns 0 which causes [sqlite3_step()] to return ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. ** ** ^Calling this routine with an argument less than or equal to zero ** turns off all busy handlers. ** ** ^(There can only be a single busy handler for a particular ** [database connection] any any given moment. If another busy handler ** was defined (using [sqlite3_busy_handler()]) prior to calling ** this routine, that other busy handler is cleared.)^ */ SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms); /* ** CAPI3REF: Convenience Routines For Running Queries ** ** Definition: A result table is memory data structure created by the ** [sqlite3_get_table()] interface. A result table records the ** complete query results from one or more queries. ** ** The table conceptually has a number of rows and columns. But ** these numbers are not part of the result table itself. These ** numbers are obtained separately. Let N be the number of rows ** and M be the number of columns. ** ** A result table is an array of pointers to zero-terminated UTF-8 strings. ** There are (N+1)*M elements in the array. The first M pointers point ** to zero-terminated strings that contain the names of the columns. ** The remaining entries all point to query results. NULL values result ** in NULL pointers. All other values are in their UTF-8 zero-terminated ** string representation as returned by [sqlite3_column_text()]. ** ** A result table might consist of one or more memory allocations. ** It is not safe to pass a result table directly to [sqlite3_free()]. ** A result table should be deallocated using [sqlite3_free_table()]. ** ** As an example of the result table format, suppose a query result ** is as follows: ** ** 
**        Name        | Age
**        -----------------------
**        Alice       | 43
**        Bob         | 28
**        Cindy       | 21
**
** ** There are two column (M==2) and three rows (N==3). Thus the ** result table has 8 entries. Suppose the result table is stored ** in an array names azResult. Then azResult holds this content: ** ** 
**        azResult[0] = "Name";
**        azResult[1] = "Age";
**        azResult[2] = "Alice";
**        azResult[3] = "43";
**        azResult[4] = "Bob";
**        azResult[5] = "28";
**        azResult[6] = "Cindy";
**        azResult[7] = "21";
**
** ** ^The sqlite3_get_table() function evaluates one or more ** semicolon-separated SQL statements in the zero-terminated UTF-8 ** string of its 2nd parameter and returns a result table to the ** pointer given in its 3rd parameter. ** ** After the application has finished with the result from sqlite3_get_table(), ** it should pass the result table pointer to sqlite3_free_table() in order to ** release the memory that was malloced. Because of the way the ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling ** function must not try to call [sqlite3_free()] directly. Only ** [sqlite3_free_table()] is able to release the memory properly and safely. ** ** ^(The sqlite3_get_table() interface is implemented as a wrapper around ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access ** to any internal data structures of SQLite. It uses only the public ** interface defined here. As a consequence, errors that occur in the ** wrapper layer outside of the internal [sqlite3_exec()] call are not ** reflected in subsequent calls to [sqlite3_errcode()] or ** [sqlite3_errmsg()].)^ */ SQLITE_API int sqlite3_get_table( sqlite3 *db, /* An open database */ const char *zSql, /* SQL to be evaluated */ char ***pazResult, /* Results of the query */ int *pnRow, /* Number of result rows written here */ int *pnColumn, /* Number of result columns written here */ char **pzErrmsg /* Error msg written here */ ); SQLITE_API void sqlite3_free_table(char **result); /* ** CAPI3REF: Formatted String Printing Functions ** ** These routines are work-alikes of the "printf()" family of functions ** from the standard C library. ** ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their ** results into memory obtained from [sqlite3_malloc()]. ** The strings returned by these two routines should be ** released by [sqlite3_free()]. ^Both routines return a ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough ** memory to hold the resulting string. ** ** ^(In sqlite3_snprintf() routine is similar to "snprintf()" from ** the standard C library. The result is written into the ** buffer supplied as the second parameter whose size is given by ** the first parameter. Note that the order of the ** first two parameters is reversed from snprintf().)^ This is an ** historical accident that cannot be fixed without breaking ** backwards compatibility. ^(Note also that sqlite3_snprintf() ** returns a pointer to its buffer instead of the number of ** characters actually written into the buffer.)^ We admit that ** the number of characters written would be a more useful return ** value but we cannot change the implementation of sqlite3_snprintf() ** now without breaking compatibility. ** ** ^As long as the buffer size is greater than zero, sqlite3_snprintf() ** guarantees that the buffer is always zero-terminated. ^The first ** parameter "n" is the total size of the buffer, including space for ** the zero terminator. So the longest string that can be completely ** written will be n-1 characters. ** ** These routines all implement some additional formatting ** options that are useful for constructing SQL statements. ** All of the usual printf() formatting options apply. In addition, there ** is are "%q", "%Q", and "%z" options. ** ** ^(The %q option works like %s in that it substitutes a null-terminated ** string from the argument list. But %q also doubles every '\'' character. ** %q is designed for use inside a string literal.)^ By doubling each '\'' ** character it escapes that character and allows it to be inserted into ** the string. ** ** For example, assume the string variable zText contains text as follows: ** ** 
**  char *zText = "It's a happy day!";
**
** ** One can use this text in an SQL statement as follows: ** ** 
**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
**  sqlite3_exec(db, zSQL, 0, 0, 0);
**  sqlite3_free(zSQL);
**
** ** Because the %q format string is used, the '\'' character in zText ** is escaped and the SQL generated is as follows: ** ** 
**  INSERT INTO table1 VALUES('It''s a happy day!')
**
** ** This is correct. Had we used %s instead of %q, the generated SQL ** would have looked like this: ** ** 
**  INSERT INTO table1 VALUES('It's a happy day!');
**
** ** This second example is an SQL syntax error. As a general rule you should ** always use %q instead of %s when inserting text into a string literal. ** ** ^(The %Q option works like %q except it also adds single quotes around ** the outside of the total string. Additionally, if the parameter in the ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without ** single quotes).)^ So, for example, one could say: ** ** 
**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
**  sqlite3_exec(db, zSQL, 0, 0, 0);
**  sqlite3_free(zSQL);
**
** ** The code above will render a correct SQL statement in the zSQL ** variable even if the zText variable is a NULL pointer. ** ** ^(The "%z" formatting option works like "%s" but with the ** addition that after the string has been read and copied into ** the result, [sqlite3_free()] is called on the input string.)^ */ SQLITE_API char *sqlite3_mprintf(const char*,...); SQLITE_API char *sqlite3_vmprintf(const char*, va_list); SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...); /* ** CAPI3REF: Memory Allocation Subsystem ** ** The SQLite core uses these three routines for all of its own ** internal memory allocation needs. "Core" in the previous sentence ** does not include operating-system specific VFS implementation. The ** Windows VFS uses native malloc() and free() for some operations. ** ** ^The sqlite3_malloc() routine returns a pointer to a block ** of memory at least N bytes in length, where N is the parameter. ** ^If sqlite3_malloc() is unable to obtain sufficient free ** memory, it returns a NULL pointer. ^If the parameter N to ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns ** a NULL pointer. ** ** ^Calling sqlite3_free() with a pointer previously returned ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so ** that it might be reused. ^The sqlite3_free() routine is ** a no-op if is called with a NULL pointer. Passing a NULL pointer ** to sqlite3_free() is harmless. After being freed, memory ** should neither be read nor written. Even reading previously freed ** memory might result in a segmentation fault or other severe error. ** Memory corruption, a segmentation fault, or other severe error ** might result if sqlite3_free() is called with a non-NULL pointer that ** was not obtained from sqlite3_malloc() or sqlite3_realloc(). ** ** ^(The sqlite3_realloc() interface attempts to resize a ** prior memory allocation to be at least N bytes, where N is the ** second parameter. The memory allocation to be resized is the first ** parameter.)^ ^ If the first parameter to sqlite3_realloc() ** is a NULL pointer then its behavior is identical to calling ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). ** ^If the second parameter to sqlite3_realloc() is zero or ** negative then the behavior is exactly the same as calling ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). ** ^sqlite3_realloc() returns a pointer to a memory allocation ** of at least N bytes in size or NULL if sufficient memory is unavailable. ** ^If M is the size of the prior allocation, then min(N,M) bytes ** of the prior allocation are copied into the beginning of buffer returned ** by sqlite3_realloc() and the prior allocation is freed. ** ^If sqlite3_realloc() returns NULL, then the prior allocation ** is not freed. ** ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() ** is always aligned to at least an 8 byte boundary. ** ** In SQLite version 3.5.0 and 3.5.1, it was possible to define ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in ** implementation of these routines to be omitted. That capability ** is no longer provided. Only built-in memory allocators can be used. ** ** The Windows OS interface layer calls ** the system malloc() and free() directly when converting ** filenames between the UTF-8 encoding used by SQLite ** and whatever filename encoding is used by the particular Windows ** installation. Memory allocation errors are detected, but ** they are reported back as [SQLITE_CANTOPEN] or ** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. ** ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] ** must be either NULL or else pointers obtained from a prior ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have ** not yet been released. ** ** The application must not read or write any part of ** a block of memory after it has been released using ** [sqlite3_free()] or [sqlite3_realloc()]. */ SQLITE_API void *sqlite3_malloc(int); SQLITE_API void *sqlite3_realloc(void*, int); SQLITE_API void sqlite3_free(void*); /* ** CAPI3REF: Memory Allocator Statistics ** ** SQLite provides these two interfaces for reporting on the status ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] ** routines, which form the built-in memory allocation subsystem. ** ** ^The [sqlite3_memory_used()] routine returns the number of bytes ** of memory currently outstanding (malloced but not freed). ** ^The [sqlite3_memory_highwater()] routine returns the maximum ** value of [sqlite3_memory_used()] since the high-water mark ** was last reset. ^The values returned by [sqlite3_memory_used()] and ** [sqlite3_memory_highwater()] include any overhead ** added by SQLite in its implementation of [sqlite3_malloc()], ** but not overhead added by the any underlying system library ** routines that [sqlite3_malloc()] may call. ** ** ^The memory high-water mark is reset to the current value of ** [sqlite3_memory_used()] if and only if the parameter to ** [sqlite3_memory_highwater()] is true. ^The value returned ** by [sqlite3_memory_highwater(1)] is the high-water mark ** prior to the reset. */ SQLITE_API sqlite3_int64 sqlite3_memory_used(void); SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag); /* ** CAPI3REF: Pseudo-Random Number Generator ** ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to ** select random [ROWID | ROWIDs] when inserting new records into a table that ** already uses the largest possible [ROWID]. The PRNG is also used for ** the build-in random() and randomblob() SQL functions. This interface allows ** applications to access the same PRNG for other purposes. ** ** ^A call to this routine stores N bytes of randomness into buffer P. ** ** ^The first time this routine is invoked (either internally or by ** the application) the PRNG is seeded using randomness obtained ** from the xRandomness method of the default [sqlite3_vfs] object. ** ^On all subsequent invocations, the pseudo-randomness is generated ** internally and without recourse to the [sqlite3_vfs] xRandomness ** method. */ SQLITE_API void sqlite3_randomness(int N, void *P); /* ** CAPI3REF: Compile-Time Authorization Callbacks ** ** ^This routine registers a authorizer callback with a particular ** [database connection], supplied in the first argument. ** ^The authorizer callback is invoked as SQL statements are being compiled ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various ** points during the compilation process, as logic is being created ** to perform various actions, the authorizer callback is invoked to ** see if those actions are allowed. ^The authorizer callback should ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the ** specific action but allow the SQL statement to continue to be ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be ** rejected with an error. ^If the authorizer callback returns ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] ** then the [sqlite3_prepare_v2()] or equivalent call that triggered ** the authorizer will fail with an error message. ** ** When the callback returns [SQLITE_OK], that means the operation ** requested is ok. ^When the callback returns [SQLITE_DENY], the ** [sqlite3_prepare_v2()] or equivalent call that triggered the ** authorizer will fail with an error message explaining that ** access is denied. ** ** ^The first parameter to the authorizer callback is a copy of the third ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter ** to the callback is an integer [SQLITE_COPY | action code] that specifies ** the particular action to be authorized. ^The third through sixth parameters ** to the callback are zero-terminated strings that contain additional ** details about the action to be authorized. ** ** ^If the action code is [SQLITE_READ] ** and the callback returns [SQLITE_IGNORE] then the ** [prepared statement] statement is constructed to substitute ** a NULL value in place of the table column that would have ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] ** return can be used to deny an untrusted user access to individual ** columns of a table. ** ^If the action code is [SQLITE_DELETE] and the callback returns ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the ** [truncate optimization] is disabled and all rows are deleted individually. ** ** An authorizer is used when [sqlite3_prepare | preparing] ** SQL statements from an untrusted source, to ensure that the SQL statements ** do not try to access data they are not allowed to see, or that they do not ** try to execute malicious statements that damage the database. For ** example, an application may allow a user to enter arbitrary ** SQL queries for evaluation by a database. But the application does ** not want the user to be able to make arbitrary changes to the ** database. An authorizer could then be put in place while the ** user-entered SQL is being [sqlite3_prepare | prepared] that ** disallows everything except [SELECT] statements. ** ** Applications that need to process SQL from untrusted sources ** might also consider lowering resource limits using [sqlite3_limit()] ** and limiting database size using the [max_page_count] [PRAGMA] ** in addition to using an authorizer. ** ** ^(Only a single authorizer can be in place on a database connection ** at a time. Each call to sqlite3_set_authorizer overrides the ** previous call.)^ ^Disable the authorizer by installing a NULL callback. ** The authorizer is disabled by default. ** ** The authorizer callback must not do anything that will modify ** the database connection that invoked the authorizer callback. ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their ** database connections for the meaning of "modify" in this paragraph. ** ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the ** statement might be re-prepared during [sqlite3_step()] due to a ** schema change. Hence, the application should ensure that the ** correct authorizer callback remains in place during the [sqlite3_step()]. ** ** ^Note that the authorizer callback is invoked only during ** [sqlite3_prepare()] or its variants. Authorization is not ** performed during statement evaluation in [sqlite3_step()], unless ** as stated in the previous paragraph, sqlite3_step() invokes ** sqlite3_prepare_v2() to reprepare a statement after a schema change. */ SQLITE_API int sqlite3_set_authorizer( sqlite3*, int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), void *pUserData ); /* ** CAPI3REF: Authorizer Return Codes ** ** The [sqlite3_set_authorizer | authorizer callback function] must ** return either [SQLITE_OK] or one of these two constants in order ** to signal SQLite whether or not the action is permitted. See the ** [sqlite3_set_authorizer | authorizer documentation] for additional ** information. */ #define SQLITE_DENY 1 /* Abort the SQL statement with an error */ #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ /* ** CAPI3REF: Authorizer Action Codes ** ** The [sqlite3_set_authorizer()] interface registers a callback function ** that is invoked to authorize certain SQL statement actions. The ** second parameter to the callback is an integer code that specifies ** what action is being authorized. These are the integer action codes that ** the authorizer callback may be passed. ** ** These action code values signify what kind of operation is to be ** authorized. The 3rd and 4th parameters to the authorization ** callback function will be parameters or NULL depending on which of these ** codes is used as the second parameter. ^(The 5th parameter to the ** authorizer callback is the name of the database ("main", "temp", ** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback ** is the name of the inner-most trigger or view that is responsible for ** the access attempt or NULL if this access attempt is directly from ** top-level SQL code. */ /******************************************* 3rd ************ 4th ***********/ #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ #define SQLITE_CREATE_VIEW 8 /* View Name NULL */ #define SQLITE_DELETE 9 /* Table Name NULL */ #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ #define SQLITE_DROP_TABLE 11 /* Table Name NULL */ #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ #define SQLITE_DROP_VIEW 17 /* View Name NULL */ #define SQLITE_INSERT 18 /* Table Name NULL */ #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ #define SQLITE_READ 20 /* Table Name Column Name */ #define SQLITE_SELECT 21 /* NULL NULL */ #define SQLITE_TRANSACTION 22 /* Operation NULL */ #define SQLITE_UPDATE 23 /* Table Name Column Name */ #define SQLITE_ATTACH 24 /* Filename NULL */ #define SQLITE_DETACH 25 /* Database Name NULL */ #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ #define SQLITE_REINDEX 27 /* Index Name NULL */ #define SQLITE_ANALYZE 28 /* Table Name NULL */ #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ #define SQLITE_FUNCTION 31 /* NULL Function Name */ #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ #define SQLITE_COPY 0 /* No longer used */ /* ** CAPI3REF: Tracing And Profiling Functions ** ** These routines register callback functions that can be used for ** tracing and profiling the execution of SQL statements. ** ** ^The callback function registered by sqlite3_trace() is invoked at ** various times when an SQL statement is being run by [sqlite3_step()]. ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the ** SQL statement text as the statement first begins executing. ** ^(Additional sqlite3_trace() callbacks might occur ** as each triggered subprogram is entered. The callbacks for triggers ** contain a UTF-8 SQL comment that identifies the trigger.)^ ** ** ^The callback function registered by sqlite3_profile() is invoked ** as each SQL statement finishes. ^The profile callback contains ** the original statement text and an estimate of wall-clock time ** of how long that statement took to run. */ SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, void(*xProfile)(void*,const char*,sqlite3_uint64), void*); /* ** CAPI3REF: Query Progress Callbacks ** ** ^This routine configures a callback function - the ** progress callback - that is invoked periodically during long ** running calls to [sqlite3_exec()], [sqlite3_step()] and ** [sqlite3_get_table()]. An example use for this ** interface is to keep a GUI updated during a large query. ** ** ^If the progress callback returns non-zero, the operation is ** interrupted. This feature can be used to implement a ** "Cancel" button on a GUI progress dialog box. ** ** The progress handler must not do anything that will modify ** the database connection that invoked the progress handler. ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their ** database connections for the meaning of "modify" in this paragraph. ** */ SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); /* ** CAPI3REF: Opening A New Database Connection ** ** ^These routines open an SQLite database file whose name is given by the ** filename argument. ^The filename argument is interpreted as UTF-8 for ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte ** order for sqlite3_open16(). ^(A [database connection] handle is usually ** returned in *ppDb, even if an error occurs. The only exception is that ** if SQLite is unable to allocate memory to hold the [sqlite3] object, ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] ** object.)^ ^(If the database is opened (and/or created) successfully, then ** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain ** an English language description of the error following a failure of any ** of the sqlite3_open() routines. ** ** ^The default encoding for the database will be UTF-8 if ** sqlite3_open() or sqlite3_open_v2() is called and ** UTF-16 in the native byte order if sqlite3_open16() is used. ** ** Whether or not an error occurs when it is opened, resources ** associated with the [database connection] handle should be released by ** passing it to [sqlite3_close()] when it is no longer required. ** ** The sqlite3_open_v2() interface works like sqlite3_open() ** except that it accepts two additional parameters for additional control ** over the new database connection. ^(The flags parameter to ** sqlite3_open_v2() can take one of ** the following three values, optionally combined with the ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], ** and/or [SQLITE_OPEN_PRIVATECACHE] flags:)^ ** **
** ^(
[SQLITE_OPEN_READONLY]
**
The database is opened in read-only mode. If the database does not ** already exist, an error is returned.
)^ ** ** ^(
[SQLITE_OPEN_READWRITE]
**
The database is opened for reading and writing if possible, or reading ** only if the file is write protected by the operating system. In either ** case the database must already exist, otherwise an error is returned.
)^ ** ** ^(
[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]
**
The database is opened for reading and writing, and is creates it if ** it does not already exist. This is the behavior that is always used for ** sqlite3_open() and sqlite3_open16().
)^ **
** ** If the 3rd parameter to sqlite3_open_v2() is not one of the ** combinations shown above or one of the combinations shown above combined ** with the [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], ** [SQLITE_OPEN_SHAREDCACHE] and/or [SQLITE_OPEN_SHAREDCACHE] flags, ** then the behavior is undefined. ** ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection ** opens in the multi-thread [threading mode] as long as the single-thread ** mode has not been set at compile-time or start-time. ^If the ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens ** in the serialized [threading mode] unless single-thread was ** previously selected at compile-time or start-time. ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be ** eligible to use [shared cache mode], regardless of whether or not shared ** cache is enabled using [sqlite3_enable_shared_cache()]. ^The ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not ** participate in [shared cache mode] even if it is enabled. ** ** ^If the filename is ":memory:", then a private, temporary in-memory database ** is created for the connection. ^This in-memory database will vanish when ** the database connection is closed. Future versions of SQLite might ** make use of additional special filenames that begin with the ":" character. ** It is recommended that when a database filename actually does begin with ** a ":" character you should prefix the filename with a pathname such as ** "./" to avoid ambiguity. ** ** ^If the filename is an empty string, then a private, temporary ** on-disk database will be created. ^This private database will be ** automatically deleted as soon as the database connection is closed. ** ** ^The fourth parameter to sqlite3_open_v2() is the name of the ** [sqlite3_vfs] object that defines the operating system interface that ** the new database connection should use. ^If the fourth parameter is ** a NULL pointer then the default [sqlite3_vfs] object is used. ** ** Note to Windows users: The encoding used for the filename argument ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever ** codepage is currently defined. Filenames containing international ** characters must be converted to UTF-8 prior to passing them into ** sqlite3_open() or sqlite3_open_v2(). */ SQLITE_API int sqlite3_open( const char *filename, /* Database filename (UTF-8) */ sqlite3 **ppDb /* OUT: SQLite db handle */ ); SQLITE_API int sqlite3_open16( const void *filename, /* Database filename (UTF-16) */ sqlite3 **ppDb /* OUT: SQLite db handle */ ); SQLITE_API int sqlite3_open_v2( const char *filename, /* Database filename (UTF-8) */ sqlite3 **ppDb, /* OUT: SQLite db handle */ int flags, /* Flags */ const char *zVfs /* Name of VFS module to use */ ); /* ** CAPI3REF: Error Codes And Messages ** ** ^The sqlite3_errcode() interface returns the numeric [result code] or ** [extended result code] for the most recent failed sqlite3_* API call ** associated with a [database connection]. If a prior API call failed ** but the most recent API call succeeded, the return value from ** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() ** interface is the same except that it always returns the ** [extended result code] even when extended result codes are ** disabled. ** ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language ** text that describes the error, as either UTF-8 or UTF-16 respectively. ** ^(Memory to hold the error message string is managed internally. ** The application does not need to worry about freeing the result. ** However, the error string might be overwritten or deallocated by ** subsequent calls to other SQLite interface functions.)^ ** ** When the serialized [threading mode] is in use, it might be the ** case that a second error occurs on a separate thread in between ** the time of the first error and the call to these interfaces. ** When that happens, the second error will be reported since these ** interfaces always report the most recent result. To avoid ** this, each thread can obtain exclusive use of the [database connection] D ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after ** all calls to the interfaces listed here are completed. ** ** If an interface fails with SQLITE_MISUSE, that means the interface ** was invoked incorrectly by the application. In that case, the ** error code and message may or may not be set. */ SQLITE_API int sqlite3_errcode(sqlite3 *db); SQLITE_API int sqlite3_extended_errcode(sqlite3 *db); SQLITE_API const char *sqlite3_errmsg(sqlite3*); SQLITE_API const void *sqlite3_errmsg16(sqlite3*); /* ** CAPI3REF: SQL Statement Object ** KEYWORDS: {prepared statement} {prepared statements} ** ** An instance of this object represents a single SQL statement. ** This object is variously known as a "prepared statement" or a ** "compiled SQL statement" or simply as a "statement". ** ** The life of a statement object goes something like this: ** **
    **
  1. Create the object using [sqlite3_prepare_v2()] or a related ** function. **
  2. Bind values to [host parameters] using the sqlite3_bind_*() ** interfaces. **
  3. Run the SQL by calling [sqlite3_step()] one or more times. **
  4. Reset the statement using [sqlite3_reset()] then go back ** to step 2. Do this zero or more times. **
  5. Destroy the object using [sqlite3_finalize()]. **
** ** Refer to documentation on individual methods above for additional ** information. */ typedef struct sqlite3_stmt sqlite3_stmt; /* ** CAPI3REF: Run-time Limits ** ** ^(This interface allows the size of various constructs to be limited ** on a connection by connection basis. The first parameter is the ** [database connection] whose limit is to be set or queried. The ** second parameter is one of the [limit categories] that define a ** class of constructs to be size limited. The third parameter is the ** new limit for that construct. The function returns the old limit.)^ ** ** ^If the new limit is a negative number, the limit is unchanged. ** ^(For the limit category of SQLITE_LIMIT_XYZ there is a ** [limits | hard upper bound] ** set by a compile-time C preprocessor macro named ** [limits | SQLITE_MAX_XYZ]. ** (The "_LIMIT_" in the name is changed to "_MAX_".))^ ** ^Attempts to increase a limit above its hard upper bound are ** silently truncated to the hard upper bound. ** ** Run-time limits are intended for use in applications that manage ** both their own internal database and also databases that are controlled ** by untrusted external sources. An example application might be a ** web browser that has its own databases for storing history and ** separate databases controlled by JavaScript applications downloaded ** off the Internet. The internal databases can be given the ** large, default limits. Databases managed by external sources can ** be given much smaller limits designed to prevent a denial of service ** attack. Developers might also want to use the [sqlite3_set_authorizer()] ** interface to further control untrusted SQL. The size of the database ** created by an untrusted script can be contained using the ** [max_page_count] [PRAGMA]. ** ** New run-time limit categories may be added in future releases. */ SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal); /* ** CAPI3REF: Run-Time Limit Categories ** KEYWORDS: {limit category} {*limit categories} ** ** These constants define various performance limits ** that can be lowered at run-time using [sqlite3_limit()]. ** The synopsis of the meanings of the various limits is shown below. ** Additional information is available at [limits | Limits in SQLite]. ** **
** ^(
SQLITE_LIMIT_LENGTH
**
The maximum size of any string or BLOB or table row.
)^ ** ** ^(
SQLITE_LIMIT_SQL_LENGTH
**
The maximum length of an SQL statement, in bytes.
)^ ** ** ^(
SQLITE_LIMIT_COLUMN
**
The maximum number of columns in a table definition or in the ** result set of a [SELECT] or the maximum number of columns in an index ** or in an ORDER BY or GROUP BY clause.
)^ ** ** ^(
SQLITE_LIMIT_EXPR_DEPTH
**
The maximum depth of the parse tree on any expression.
)^ ** ** ^(
SQLITE_LIMIT_COMPOUND_SELECT
**
The maximum number of terms in a compound SELECT statement.
)^ ** ** ^(
SQLITE_LIMIT_VDBE_OP
**
The maximum number of instructions in a virtual machine program ** used to implement an SQL statement.
)^ ** ** ^(
SQLITE_LIMIT_FUNCTION_ARG
**
The maximum number of arguments on a function.
)^ ** ** ^(
SQLITE_LIMIT_ATTACHED
**
The maximum number of [ATTACH | attached databases].)^
** ** ^(
SQLITE_LIMIT_LIKE_PATTERN_LENGTH
**
The maximum length of the pattern argument to the [LIKE] or ** [GLOB] operators.
)^ ** ** ^(
SQLITE_LIMIT_VARIABLE_NUMBER
**
The maximum number of variables in an SQL statement that can ** be bound.
)^ ** ** ^(
SQLITE_LIMIT_TRIGGER_DEPTH
**
The maximum depth of recursion for triggers.
)^ **
*/ #define SQLITE_LIMIT_LENGTH 0 #define SQLITE_LIMIT_SQL_LENGTH 1 #define SQLITE_LIMIT_COLUMN 2 #define SQLITE_LIMIT_EXPR_DEPTH 3 #define SQLITE_LIMIT_COMPOUND_SELECT 4 #define SQLITE_LIMIT_VDBE_OP 5 #define SQLITE_LIMIT_FUNCTION_ARG 6 #define SQLITE_LIMIT_ATTACHED 7 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 #define SQLITE_LIMIT_VARIABLE_NUMBER 9 #define SQLITE_LIMIT_TRIGGER_DEPTH 10 /* ** CAPI3REF: Compiling An SQL Statement ** KEYWORDS: {SQL statement compiler} ** ** To execute an SQL query, it must first be compiled into a byte-code ** program using one of these routines. ** ** The first argument, "db", is a [database connection] obtained from a ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or ** [sqlite3_open16()]. The database connection must not have been closed. ** ** The second argument, "zSql", is the statement to be compiled, encoded ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() ** use UTF-16. ** ** ^If the nByte argument is less than zero, then zSql is read up to the ** first zero terminator. ^If nByte is non-negative, then it is the maximum ** number of bytes read from zSql. ^When nByte is non-negative, the ** zSql string ends at either the first '\000' or '\u0000' character or ** the nByte-th byte, whichever comes first. If the caller knows ** that the supplied string is nul-terminated, then there is a small ** performance advantage to be gained by passing an nByte parameter that ** is equal to the number of bytes in the input string including ** the nul-terminator bytes. ** ** ^If pzTail is not NULL then *pzTail is made to point to the first byte ** past the end of the first SQL statement in zSql. These routines only ** compile the first statement in zSql, so *pzTail is left pointing to ** what remains uncompiled. ** ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be ** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set ** to NULL. ^If the input text contains no SQL (if the input is an empty ** string or a comment) then *ppStmt is set to NULL. ** The calling procedure is responsible for deleting the compiled ** SQL statement using [sqlite3_finalize()] after it has finished with it. ** ppStmt may not be NULL. ** ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; ** otherwise an [error code] is returned. ** ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are ** recommended for all new programs. The two older interfaces are retained ** for backwards compatibility, but their use is discouraged. ** ^In the "v2" interfaces, the prepared statement ** that is returned (the [sqlite3_stmt] object) contains a copy of the ** original SQL text. This causes the [sqlite3_step()] interface to ** behave differently in three ways: ** **
    **
  1. ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it ** always used to do, [sqlite3_step()] will automatically recompile the SQL ** statement and try to run it again. ^If the schema has changed in ** a way that makes the statement no longer valid, [sqlite3_step()] will still ** return [SQLITE_SCHEMA]. But unlike the legacy behavior, [SQLITE_SCHEMA] is ** now a fatal error. Calling [sqlite3_prepare_v2()] again will not make the ** error go away. Note: use [sqlite3_errmsg()] to find the text ** of the parsing error that results in an [SQLITE_SCHEMA] return. **
    2. ** **
  2. ** ^When an error occurs, [sqlite3_step()] will return one of the detailed ** [error codes] or [extended error codes]. ^The legacy behavior was that ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code ** and the application would have to make a second call to [sqlite3_reset()] ** in order to find the underlying cause of the problem. With the "v2" prepare ** interfaces, the underlying reason for the error is returned immediately. **
    3. ** **
  3. ** ^If the value of a [parameter | host parameter] in the WHERE clause might ** change the query plan for a statement, then the statement may be ** automatically recompiled (as if there had been a schema change) on the first ** [sqlite3_step()] call following any change to the ** [sqlite3_bind_text | bindings] of the [parameter]. **
    4. **
*/ SQLITE_API int sqlite3_prepare( sqlite3 *db, /* Database handle */ const char *zSql, /* SQL statement, UTF-8 encoded */ int nByte, /* Maximum length of zSql in bytes. */ sqlite3_stmt **ppStmt, /* OUT: Statement handle */ const char **pzTail /* OUT: Pointer to unused portion of zSql */ ); SQLITE_API int sqlite3_prepare_v2( sqlite3 *db, /* Database handle */ const char *zSql, /* SQL statement, UTF-8 encoded */ int nByte, /* Maximum length of zSql in bytes. */ sqlite3_stmt **ppStmt, /* OUT: Statement handle */ const char **pzTail /* OUT: Pointer to unused portion of zSql */ ); SQLITE_API int sqlite3_prepare16( sqlite3 *db, /* Database handle */ const void *zSql, /* SQL statement, UTF-16 encoded */ int nByte, /* Maximum length of zSql in bytes. */ sqlite3_stmt **ppStmt, /* OUT: Statement handle */ const void **pzTail /* OUT: Pointer to unused portion of zSql */ ); SQLITE_API int sqlite3_prepare16_v2( sqlite3 *db, /* Database handle */ const void *zSql, /* SQL statement, UTF-16 encoded */ int nByte, /* Maximum length of zSql in bytes. */ sqlite3_stmt **ppStmt, /* OUT: Statement handle */ const void **pzTail /* OUT: Pointer to unused portion of zSql */ ); /* ** CAPI3REF: Retrieving Statement SQL ** ** ^This interface can be used to retrieve a saved copy of the original ** SQL text used to create a [prepared statement] if that statement was ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. */ SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt); /* ** CAPI3REF: Dynamically Typed Value Object ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} ** ** SQLite uses the sqlite3_value object to represent all values ** that can be stored in a database table. SQLite uses dynamic typing ** for the values it stores. ^Values stored in sqlite3_value objects ** can be integers, floating point values, strings, BLOBs, or NULL. ** ** An sqlite3_value object may be either "protected" or "unprotected". ** Some interfaces require a protected sqlite3_value. Other interfaces ** will accept either a protected or an unprotected sqlite3_value. ** Every interface that accepts sqlite3_value arguments specifies ** whether or not it requires a protected sqlite3_value. ** ** The terms "protected" and "unprotected" refer to whether or not ** a mutex is held. A internal mutex is held for a protected ** sqlite3_value object but no mutex is held for an unprotected ** sqlite3_value object. If SQLite is compiled to be single-threaded ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) ** or if SQLite is run in one of reduced mutex modes ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] ** then there is no distinction between protected and unprotected ** sqlite3_value objects and they can be used interchangeably. However, ** for maximum code portability it is recommended that applications ** still make the distinction between between protected and unprotected ** sqlite3_value objects even when not strictly required. ** ** ^The sqlite3_value objects that are passed as parameters into the ** implementation of [application-defined SQL functions] are protected. ** ^The sqlite3_value object returned by ** [sqlite3_column_value()] is unprotected. ** Unprotected sqlite3_value objects may only be used with ** [sqlite3_result_value()] and [sqlite3_bind_value()]. ** The [sqlite3_value_blob | sqlite3_value_type()] family of ** interfaces require protected sqlite3_value objects. */ typedef struct Mem sqlite3_value; /* ** CAPI3REF: SQL Function Context Object ** ** The context in which an SQL function executes is stored in an ** sqlite3_context object. ^A pointer to an sqlite3_context object ** is always first parameter to [application-defined SQL functions]. ** The application-defined SQL function implementation will pass this ** pointer through into calls to [sqlite3_result_int | sqlite3_result()], ** [sqlite3_aggregate_context()], [sqlite3_user_data()], ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], ** and/or [sqlite3_set_auxdata()]. */ typedef struct sqlite3_context sqlite3_context; /* ** CAPI3REF: Binding Values To Prepared Statements ** KEYWORDS: {host parameter} {host parameters} {host parameter name} ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} ** ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, ** literals may be replaced by a [parameter] that matches one of following ** templates: ** ** ** ** In the templates above, NNN represents an integer literal, ** and VVV represents an alphanumeric identifer.)^ ^The values of these ** parameters (also called "host parameter names" or "SQL parameters") ** can be set using the sqlite3_bind_*() routines defined here. ** ** ^The first argument to the sqlite3_bind_*() routines is always ** a pointer to the [sqlite3_stmt] object returned from ** [sqlite3_prepare_v2()] or its variants. ** ** ^The second argument is the index of the SQL parameter to be set. ** ^The leftmost SQL parameter has an index of 1. ^When the same named ** SQL parameter is used more than once, second and subsequent ** occurrences have the same index as the first occurrence. ** ^The index for named parameters can be looked up using the ** [sqlite3_bind_parameter_index()] API if desired. ^The index ** for "?NNN" parameters is the value of NNN. ** ^The NNN value must be between 1 and the [sqlite3_limit()] ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). ** ** ^The third argument is the value to bind to the parameter. ** ** ^(In those routines that have a fourth argument, its value is the ** number of bytes in the parameter. To be clear: the value is the ** number of bytes in the value, not the number of characters.)^ ** ^If the fourth parameter is negative, the length of the string is ** the number of bytes up to the first zero terminator. ** ** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or ** string after SQLite has finished with it. ^If the fifth argument is ** the special value [SQLITE_STATIC], then SQLite assumes that the ** information is in static, unmanaged space and does not need to be freed. ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then ** SQLite makes its own private copy of the data immediately, before ** the sqlite3_bind_*() routine returns. ** ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that ** is filled with zeroes. ^A zeroblob uses a fixed amount of memory ** (just an integer to hold its size) while it is being processed. ** Zeroblobs are intended to serve as placeholders for BLOBs whose ** content is later written using ** [sqlite3_blob_open | incremental BLOB I/O] routines. ** ^A negative value for the zeroblob results in a zero-length BLOB. ** ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer ** for the [prepared statement] or with a prepared statement for which ** [sqlite3_step()] has been called more recently than [sqlite3_reset()], ** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() ** routine is passed a [prepared statement] that has been finalized, the ** result is undefined and probably harmful. ** ** ^Bindings are not cleared by the [sqlite3_reset()] routine. ** ^Unbound parameters are interpreted as NULL. ** ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an ** [error code] if anything goes wrong. ** ^[SQLITE_RANGE] is returned if the parameter ** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. ** ** See also: [sqlite3_bind_parameter_count()], ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. */ SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double); SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int); SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int); SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); /* ** CAPI3REF: Number Of SQL Parameters ** ** ^This routine can be used to find the number of [SQL parameters] ** in a [prepared statement]. SQL parameters are tokens of the ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as ** placeholders for values that are [sqlite3_bind_blob | bound] ** to the parameters at a later time. ** ** ^(This routine actually returns the index of the largest (rightmost) ** parameter. For all forms except ?NNN, this will correspond to the ** number of unique parameters. If parameters of the ?NNN form are used, ** there may be gaps in the list.)^ ** ** See also: [sqlite3_bind_blob|sqlite3_bind()], ** [sqlite3_bind_parameter_name()], and ** [sqlite3_bind_parameter_index()]. */ SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*); /* ** CAPI3REF: Name Of A Host Parameter ** ** ^The sqlite3_bind_parameter_name(P,N) interface returns ** the name of the N-th [SQL parameter] in the [prepared statement] P. ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" ** respectively. ** In other words, the initial ":" or "$" or "@" or "?" ** is included as part of the name.)^ ** ^Parameters of the form "?" without a following integer have no name ** and are referred to as "nameless" or "anonymous parameters". ** ** ^The first host parameter has an index of 1, not 0. ** ** ^If the value N is out of range or if the N-th parameter is ** nameless, then NULL is returned. ^The returned string is ** always in UTF-8 encoding even if the named parameter was ** originally specified as UTF-16 in [sqlite3_prepare16()] or ** [sqlite3_prepare16_v2()]. ** ** See also: [sqlite3_bind_blob|sqlite3_bind()], ** [sqlite3_bind_parameter_count()], and ** [sqlite3_bind_parameter_index()]. */ SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); /* ** CAPI3REF: Index Of A Parameter With A Given Name ** ** ^Return the index of an SQL parameter given its name. ^The ** index value returned is suitable for use as the second ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero ** is returned if no matching parameter is found. ^The parameter ** name must be given in UTF-8 even if the original statement ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. ** ** See also: [sqlite3_bind_blob|sqlite3_bind()], ** [sqlite3_bind_parameter_count()], and ** [sqlite3_bind_parameter_index()]. */ SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); /* ** CAPI3REF: Reset All Bindings On A Prepared Statement ** ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset ** the [sqlite3_bind_blob | bindings] on a [prepared statement]. ** ^Use this routine to reset all host parameters to NULL. */ SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*); /* ** CAPI3REF: Number Of Columns In A Result Set ** ** ^Return the number of columns in the result set returned by the ** [prepared statement]. ^This routine returns 0 if pStmt is an SQL ** statement that does not return data (for example an [UPDATE]). */ SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt); /* ** CAPI3REF: Column Names In A Result Set ** ** ^These routines return the name assigned to a particular column ** in the result set of a [SELECT] statement. ^The sqlite3_column_name() ** interface returns a pointer to a zero-terminated UTF-8 string ** and sqlite3_column_name16() returns a pointer to a zero-terminated ** UTF-16 string. ^The first parameter is the [prepared statement] ** that implements the [SELECT] statement. ^The second parameter is the ** column number. ^The leftmost column is number 0. ** ** ^The returned string pointer is valid until either the [prepared statement] ** is destroyed by [sqlite3_finalize()] or until the next call to ** sqlite3_column_name() or sqlite3_column_name16() on the same column. ** ** ^If sqlite3_malloc() fails during the processing of either routine ** (for example during a conversion from UTF-8 to UTF-16) then a ** NULL pointer is returned. ** ** ^The name of a result column is the value of the "AS" clause for ** that column, if there is an AS clause. If there is no AS clause ** then the name of the column is unspecified and may change from ** one release of SQLite to the next. */ SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N); SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N); /* ** CAPI3REF: Source Of Data In A Query Result ** ** ^These routines provide a means to determine the database, table, and ** table column that is the origin of a particular result column in ** [SELECT] statement. ** ^The name of the database or table or column can be returned as ** either a UTF-8 or UTF-16 string. ^The _database_ routines return ** the database name, the _table_ routines return the table name, and ** the origin_ routines return the column name. ** ^The returned string is valid until the [prepared statement] is destroyed ** using [sqlite3_finalize()] or until the same information is requested ** again in a different encoding. ** ** ^The names returned are the original un-aliased names of the ** database, table, and column. ** ** ^The first argument to these interfaces is a [prepared statement]. ** ^These functions return information about the Nth result column returned by ** the statement, where N is the second function argument. ** ^The left-most column is column 0 for these routines. ** ** ^If the Nth column returned by the statement is an expression or ** subquery and is not a column value, then all of these functions return ** NULL. ^These routine might also return NULL if a memory allocation error ** occurs. ^Otherwise, they return the name of the attached database, table, ** or column that query result column was extracted from. ** ** ^As with all other SQLite APIs, those whose names end with "16" return ** UTF-16 encoded strings and the other functions return UTF-8. ** ** ^These APIs are only available if the library was compiled with the ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. ** ** If two or more threads call one or more of these routines against the same ** prepared statement and column at the same time then the results are ** undefined. ** ** If two or more threads call one or more ** [sqlite3_column_database_name | column metadata interfaces] ** for the same [prepared statement] and result column ** at the same time then the results are undefined. */ SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int); SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int); SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int); SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int); SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int); SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); /* ** CAPI3REF: Declared Datatype Of A Query Result ** ** ^(The first parameter is a [prepared statement]. ** If this statement is a [SELECT] statement and the Nth column of the ** returned result set of that [SELECT] is a table column (not an ** expression or subquery) then the declared type of the table ** column is returned.)^ ^If the Nth column of the result set is an ** expression or subquery, then a NULL pointer is returned. ** ^The returned string is always UTF-8 encoded. ** ** ^(For example, given the database schema: ** ** CREATE TABLE t1(c1 VARIANT); ** ** and the following statement to be compiled: ** ** SELECT c1 + 1, c1 FROM t1; ** ** this routine would return the string "VARIANT" for the second result ** column (i==1), and a NULL pointer for the first result column (i==0).)^ ** ** ^SQLite uses dynamic run-time typing. ^So just because a column ** is declared to contain a particular type does not mean that the ** data stored in that column is of the declared type. SQLite is ** strongly typed, but the typing is dynamic not static. ^Type ** is associated with individual values, not with the containers ** used to hold those values. */ SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int); SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int); /* ** CAPI3REF: Evaluate An SQL Statement ** ** After a [prepared statement] has been prepared using either ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function ** must be called one or more times to evaluate the statement. ** ** The details of the behavior of the sqlite3_step() interface depend ** on whether the statement was prepared using the newer "v2" interface ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the ** new "v2" interface is recommended for new applications but the legacy ** interface will continue to be supported. ** ** ^In the legacy interface, the return value will be either [SQLITE_BUSY], ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. ** ^With the "v2" interface, any of the other [result codes] or ** [extended result codes] might be returned as well. ** ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the ** database locks it needs to do its job. ^If the statement is a [COMMIT] ** or occurs outside of an explicit transaction, then you can retry the ** statement. If the statement is not a [COMMIT] and occurs within a ** explicit transaction then you should rollback the transaction before ** continuing. ** ** ^[SQLITE_DONE] means that the statement has finished executing ** successfully. sqlite3_step() should not be called again on this virtual ** machine without first calling [sqlite3_reset()] to reset the virtual ** machine back to its initial state. ** ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] ** is returned each time a new row of data is ready for processing by the ** caller. The values may be accessed using the [column access functions]. ** sqlite3_step() is called again to retrieve the next row of data. ** ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint ** violation) has occurred. sqlite3_step() should not be called again on ** the VM. More information may be found by calling [sqlite3_errmsg()]. ** ^With the legacy interface, a more specific error code (for example, ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) ** can be obtained by calling [sqlite3_reset()] on the ** [prepared statement]. ^In the "v2" interface, ** the more specific error code is returned directly by sqlite3_step(). ** ** [SQLITE_MISUSE] means that the this routine was called inappropriately. ** Perhaps it was called on a [prepared statement] that has ** already been [sqlite3_finalize | finalized] or on one that had ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could ** be the case that the same database connection is being used by two or ** more threads at the same moment in time. ** ** For all versions of SQLite up to and including 3.6.23.1, it was required ** after sqlite3_step() returned anything other than [SQLITE_ROW] that ** [sqlite3_reset()] be called before any subsequent invocation of ** sqlite3_step(). Failure to invoke [sqlite3_reset()] in this way would ** result in an [SQLITE_MISUSE] return from sqlite3_step(). But after ** version 3.6.23.1, sqlite3_step() began calling [sqlite3_reset()] ** automatically in this circumstance rather than returning [SQLITE_MISUSE]. ** ** Goofy Interface Alert: In the legacy interface, the sqlite3_step() ** API always returns a generic error code, [SQLITE_ERROR], following any ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the ** specific [error codes] that better describes the error. ** We admit that this is a goofy design. The problem has been fixed ** with the "v2" interface. If you prepare all of your SQL statements ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, ** then the more specific [error codes] are returned directly ** by sqlite3_step(). The use of the "v2" interface is recommended. */ SQLITE_API int sqlite3_step(sqlite3_stmt*); /* ** CAPI3REF: Number of columns in a result set ** ** ^The sqlite3_data_count(P) the number of columns in the ** of the result set of [prepared statement] P. */ SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt); /* ** CAPI3REF: Fundamental Datatypes ** KEYWORDS: SQLITE_TEXT ** ** ^(Every value in SQLite has one of five fundamental datatypes: ** ** )^ ** ** These constants are codes for each of those types. ** ** Note that the SQLITE_TEXT constant was also used in SQLite version 2 ** for a completely different meaning. Software that links against both ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not ** SQLITE_TEXT. */ #define SQLITE_INTEGER 1 #define SQLITE_FLOAT 2 #define SQLITE_BLOB 4 #define SQLITE_NULL 5 #ifdef SQLITE_TEXT # undef SQLITE_TEXT #else # define SQLITE_TEXT 3 #endif #define SQLITE3_TEXT 3 /* ** CAPI3REF: Result Values From A Query ** KEYWORDS: {column access functions} ** ** These routines form the "result set" interface. ** ** ^These routines return information about a single column of the current ** result row of a query. ^In every case the first argument is a pointer ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] ** that was returned from [sqlite3_prepare_v2()] or one of its variants) ** and the second argument is the index of the column for which information ** should be returned. ^The leftmost column of the result set has the index 0. ** ^The number of columns in the result can be determined using ** [sqlite3_column_count()]. ** ** If the SQL statement does not currently point to a valid row, or if the ** column index is out of range, the result is undefined. ** These routines may only be called when the most recent call to ** [sqlite3_step()] has returned [SQLITE_ROW] and neither ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. ** If any of these routines are called after [sqlite3_reset()] or ** [sqlite3_finalize()] or after [sqlite3_step()] has returned ** something other than [SQLITE_ROW], the results are undefined. ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] ** are called from a different thread while any of these routines ** are pending, then the results are undefined. ** ** ^The sqlite3_column_type() routine returns the ** [SQLITE_INTEGER | datatype code] for the initial data type ** of the result column. ^The returned value is one of [SQLITE_INTEGER], ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value ** returned by sqlite3_column_type() is only meaningful if no type ** conversions have occurred as described below. After a type conversion, ** the value returned by sqlite3_column_type() is undefined. Future ** versions of SQLite may change the behavior of sqlite3_column_type() ** following a type conversion. ** ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() ** routine returns the number of bytes in that BLOB or string. ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts ** the string to UTF-8 and then returns the number of bytes. ** ^If the result is a numeric value then sqlite3_column_bytes() uses ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns ** the number of bytes in that string. ** ^The value returned does not include the zero terminator at the end ** of the string. ^For clarity: the value returned is the number of ** bytes in the string, not the number of characters. ** ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), ** even empty strings, are always zero terminated. ^The return ** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary ** pointer, possibly even a NULL pointer. ** ** ^The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes() ** but leaves the result in UTF-16 in native byte order instead of UTF-8. ** ^The zero terminator is not included in this count. ** ** ^The object returned by [sqlite3_column_value()] is an ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. ** If the [unprotected sqlite3_value] object returned by ** [sqlite3_column_value()] is used in any other way, including calls ** to routines like [sqlite3_value_int()], [sqlite3_value_text()], ** or [sqlite3_value_bytes()], then the behavior is undefined. ** ** These routines attempt to convert the value where appropriate. ^For ** example, if the internal representation is FLOAT and a text result ** is requested, [sqlite3_snprintf()] is used internally to perform the ** conversion automatically. ^(The following table details the conversions ** that are applied: ** **
** **
Internal
Type 		Requested
Type 		Conversion ** **
NULL INTEGER Result is 0 **
NULL FLOAT Result is 0.0 **
NULL TEXT Result is NULL pointer **
NULL BLOB Result is NULL pointer **
INTEGER FLOAT Convert from integer to float **
INTEGER TEXT ASCII rendering of the integer **
INTEGER BLOB Same as INTEGER->TEXT **
FLOAT INTEGER Convert from float to integer **
FLOAT TEXT ASCII rendering of the float **
FLOAT BLOB Same as FLOAT->TEXT **
TEXT INTEGER Use atoi() **
TEXT FLOAT Use atof() **
TEXT BLOB No change **
BLOB INTEGER Convert to TEXT then use atoi() **
BLOB FLOAT Convert to TEXT then use atof() **
BLOB TEXT Add a zero terminator if needed **
**
)^ ** ** The table above makes reference to standard C library functions atoi() ** and atof(). SQLite does not really use these functions. It has its ** own equivalent internal routines. The atoi() and atof() names are ** used in the table for brevity and because they are familiar to most ** C programmers. ** ** ^Note that when type conversions occur, pointers returned by prior ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or ** sqlite3_column_text16() may be invalidated. ** ^(Type conversions and pointer invalidations might occur ** in the following cases: ** ** )^ ** ** ^Conversions between UTF-16be and UTF-16le are always done in place and do ** not invalidate a prior pointer, though of course the content of the buffer ** that the prior pointer points to will have been modified. Other kinds ** of conversion are done in place when it is possible, but sometimes they ** are not possible and in those cases prior pointers are invalidated. ** ** ^(The safest and easiest to remember policy is to invoke these routines ** in one of the following ways: ** ** )^ ** ** In other words, you should call sqlite3_column_text(), ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result ** into the desired format, then invoke sqlite3_column_bytes() or ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls ** to sqlite3_column_text() or sqlite3_column_blob() with calls to ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() ** with calls to sqlite3_column_bytes(). ** ** ^The pointers returned are valid until a type conversion occurs as ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or ** [sqlite3_finalize()] is called. ^The memory space used to hold strings ** and BLOBs is freed automatically. Do not pass the pointers returned ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into ** [sqlite3_free()]. ** ** ^(If a memory allocation error occurs during the evaluation of any ** of these routines, a default value is returned. The default value ** is either the integer 0, the floating point number 0.0, or a NULL ** pointer. Subsequent calls to [sqlite3_errcode()] will return ** [SQLITE_NOMEM].)^ */ SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol); SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol); SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol); SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol); SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); /* ** CAPI3REF: Destroy A Prepared Statement Object ** ** ^The sqlite3_finalize() function is called to delete a [prepared statement]. ** ^If the statement was executed successfully or not executed at all, then ** SQLITE_OK is returned. ^If execution of the statement failed then an ** [error code] or [extended error code] is returned. ** ** ^This routine can be called at any point during the execution of the ** [prepared statement]. ^If the virtual machine has not ** completed execution when this routine is called, that is like ** encountering an error or an [sqlite3_interrupt | interrupt]. ** ^Incomplete updates may be rolled back and transactions canceled, ** depending on the circumstances, and the ** [error code] returned will be [SQLITE_ABORT]. */ SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt); /* ** CAPI3REF: Reset A Prepared Statement Object ** ** The sqlite3_reset() function is called to reset a [prepared statement] ** object back to its initial state, ready to be re-executed. ** ^Any SQL statement variables that had values bound to them using ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. ** Use [sqlite3_clear_bindings()] to reset the bindings. ** ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S ** back to the beginning of its program. ** ** ^If the most recent call to [sqlite3_step(S)] for the ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], ** or if [sqlite3_step(S)] has never before been called on S, ** then [sqlite3_reset(S)] returns [SQLITE_OK]. ** ** ^If the most recent call to [sqlite3_step(S)] for the ** [prepared statement] S indicated an error, then ** [sqlite3_reset(S)] returns an appropriate [error code]. ** ** ^The [sqlite3_reset(S)] interface does not change the values ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. */ SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt); /* ** CAPI3REF: Create Or Redefine SQL Functions ** KEYWORDS: {function creation routines} ** KEYWORDS: {application-defined SQL function} ** KEYWORDS: {application-defined SQL functions} ** ** ^These two functions (collectively known as "function creation routines") ** are used to add SQL functions or aggregates or to redefine the behavior ** of existing SQL functions or aggregates. The only difference between the ** two is that the second parameter, the name of the (scalar) function or ** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16 ** for sqlite3_create_function16(). ** ** ^The first parameter is the [database connection] to which the SQL ** function is to be added. ^If an application uses more than one database ** connection then application-defined SQL functions must be added ** to each database connection separately. ** ** The second parameter is the name of the SQL function to be created or ** redefined. ^The length of the name is limited to 255 bytes, exclusive of ** the zero-terminator. Note that the name length limit is in bytes, not ** characters. ^Any attempt to create a function with a longer name ** will result in [SQLITE_ERROR] being returned. ** ** ^The third parameter (nArg) ** is the number of arguments that the SQL function or ** aggregate takes. ^If this parameter is -1, then the SQL function or ** aggregate may take any number of arguments between 0 and the limit ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third ** parameter is less than -1 or greater than 127 then the behavior is ** undefined. ** ** The fourth parameter, eTextRep, specifies what ** [SQLITE_UTF8 | text encoding] this SQL function prefers for ** its parameters. Any SQL function implementation should be able to work ** work with UTF-8, UTF-16le, or UTF-16be. But some implementations may be ** more efficient with one encoding than another. ^An application may ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple ** times with the same function but with different values of eTextRep. ** ^When multiple implementations of the same function are available, SQLite ** will pick the one that involves the least amount of data conversion. ** If there is only a single implementation which does not care what text ** encoding is used, then the fourth argument should be [SQLITE_ANY]. ** ** ^(The fifth parameter is an arbitrary pointer. The implementation of the ** function can gain access to this pointer using [sqlite3_user_data()].)^ ** ** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are ** pointers to C-language functions that implement the SQL function or ** aggregate. ^A scalar SQL function requires an implementation of the xFunc ** callback only; NULL pointers should be passed as the xStep and xFinal ** parameters. ^An aggregate SQL function requires an implementation of xStep ** and xFinal and NULL should be passed for xFunc. ^To delete an existing ** SQL function or aggregate, pass NULL for all three function callbacks. ** ** ^It is permitted to register multiple implementations of the same ** functions with the same name but with either differing numbers of ** arguments or differing preferred text encodings. ^SQLite will use ** the implementation that most closely matches the way in which the ** SQL function is used. ^A function implementation with a non-negative ** nArg parameter is a better match than a function implementation with ** a negative nArg. ^A function where the preferred text encoding ** matches the database encoding is a better ** match than a function where the encoding is different. ** ^A function where the encoding difference is between UTF16le and UTF16be ** is a closer match than a function where the encoding difference is ** between UTF8 and UTF16. ** ** ^Built-in functions may be overloaded by new application-defined functions. ** ^The first application-defined function with a given name overrides all ** built-in functions in the same [database connection] with the same name. ** ^Subsequent application-defined functions of the same name only override ** prior application-defined functions that are an exact match for the ** number of parameters and preferred encoding. ** ** ^An application-defined function is permitted to call other ** SQLite interfaces. However, such calls must not ** close the database connection nor finalize or reset the prepared ** statement in which the function is running. */ SQLITE_API int sqlite3_create_function( sqlite3 *db, const char *zFunctionName, int nArg, int eTextRep, void *pApp, void (*xFunc)(sqlite3_context*,int,sqlite3_value**), void (*xStep)(sqlite3_context*,int,sqlite3_value**), void (*xFinal)(sqlite3_context*) ); SQLITE_API int sqlite3_create_function16( sqlite3 *db, const void *zFunctionName, int nArg, int eTextRep, void *pApp, void (*xFunc)(sqlite3_context*,int,sqlite3_value**), void (*xStep)(sqlite3_context*,int,sqlite3_value**), void (*xFinal)(sqlite3_context*) ); /* ** CAPI3REF: Text Encodings ** ** These constant define integer codes that represent the various ** text encodings supported by SQLite. */ #define SQLITE_UTF8 1 #define SQLITE_UTF16LE 2 #define SQLITE_UTF16BE 3 #define SQLITE_UTF16 4 /* Use native byte order */ #define SQLITE_ANY 5 /* sqlite3_create_function only */ #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ /* ** CAPI3REF: Deprecated Functions ** DEPRECATED ** ** These functions are [deprecated]. In order to maintain ** backwards compatibility with older code, these functions continue ** to be supported. However, new applications should avoid ** the use of these functions. To help encourage people to avoid ** using these functions, we are not going to tell you what they do. */ #ifndef SQLITE_OMIT_DEPRECATED SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void); SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); #endif /* ** CAPI3REF: Obtaining SQL Function Parameter Values ** ** The C-language implementation of SQL functions and aggregates uses ** this set of interface routines to access the parameter values on ** the function or aggregate. ** ** The xFunc (for scalar functions) or xStep (for aggregates) parameters ** to [sqlite3_create_function()] and [sqlite3_create_function16()] ** define callbacks that implement the SQL functions and aggregates. ** The 4th parameter to these callbacks is an array of pointers to ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for ** each parameter to the SQL function. These routines are used to ** extract values from the [sqlite3_value] objects. ** ** These routines work only with [protected sqlite3_value] objects. ** Any attempt to use these routines on an [unprotected sqlite3_value] ** object results in undefined behavior. ** ** ^These routines work just like the corresponding [column access functions] ** except that these routines take a single [protected sqlite3_value] object ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. ** ** ^The sqlite3_value_text16() interface extracts a UTF-16 string ** in the native byte-order of the host machine. ^The ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces ** extract UTF-16 strings as big-endian and little-endian respectively. ** ** ^(The sqlite3_value_numeric_type() interface attempts to apply ** numeric affinity to the value. This means that an attempt is ** made to convert the value to an integer or floating point. If ** such a conversion is possible without loss of information (in other ** words, if the value is a string that looks like a number) ** then the conversion is performed. Otherwise no conversion occurs. ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ ** ** Please pay particular attention to the fact that the pointer returned ** from [sqlite3_value_blob()], [sqlite3_value_text()], or ** [sqlite3_value_text16()] can be invalidated by a subsequent call to ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], ** or [sqlite3_value_text16()]. ** ** These routines must be called from the same thread as ** the SQL function that supplied the [sqlite3_value*] parameters. */ SQLITE_API const void *sqlite3_value_blob(sqlite3_value*); SQLITE_API int sqlite3_value_bytes(sqlite3_value*); SQLITE_API int sqlite3_value_bytes16(sqlite3_value*); SQLITE_API double sqlite3_value_double(sqlite3_value*); SQLITE_API int sqlite3_value_int(sqlite3_value*); SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*); SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*); SQLITE_API const void *sqlite3_value_text16(sqlite3_value*); SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*); SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*); SQLITE_API int sqlite3_value_type(sqlite3_value*); SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*); /* ** CAPI3REF: Obtain Aggregate Function Context ** ** Implementions of aggregate SQL functions use this ** routine to allocate memory for storing their state. ** ** ^The first time the sqlite3_aggregate_context(C,N) routine is called ** for a particular aggregate function, SQLite ** allocates N of memory, zeroes out that memory, and returns a pointer ** to the new memory. ^On second and subsequent calls to ** sqlite3_aggregate_context() for the same aggregate function instance, ** the same buffer is returned. Sqlite3_aggregate_context() is normally ** called once for each invocation of the xStep callback and then one ** last time when the xFinal callback is invoked. ^(When no rows match ** an aggregate query, the xStep() callback of the aggregate function ** implementation is never called and xFinal() is called exactly once. ** In those cases, sqlite3_aggregate_context() might be called for the ** first time from within xFinal().)^ ** ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is ** less than or equal to zero or if a memory allocate error occurs. ** ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is ** determined by the N parameter on first successful call. Changing the ** value of N in subsequent call to sqlite3_aggregate_context() within ** the same aggregate function instance will not resize the memory ** allocation.)^ ** ** ^SQLite automatically frees the memory allocated by ** sqlite3_aggregate_context() when the aggregate query concludes. ** ** The first parameter must be a copy of the ** [sqlite3_context | SQL function context] that is the first parameter ** to the xStep or xFinal callback routine that implements the aggregate ** function. ** ** This routine must be called from the same thread in which ** the aggregate SQL function is running. */ SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); /* ** CAPI3REF: User Data For Functions ** ** ^The sqlite3_user_data() interface returns a copy of ** the pointer that was the pUserData parameter (the 5th parameter) ** of the [sqlite3_create_function()] ** and [sqlite3_create_function16()] routines that originally ** registered the application defined function. ** ** This routine must be called from the same thread in which ** the application-defined function is running. */ SQLITE_API void *sqlite3_user_data(sqlite3_context*); /* ** CAPI3REF: Database Connection For Functions ** ** ^The sqlite3_context_db_handle() interface returns a copy of ** the pointer to the [database connection] (the 1st parameter) ** of the [sqlite3_create_function()] ** and [sqlite3_create_function16()] routines that originally ** registered the application defined function. */ SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*); /* ** CAPI3REF: Function Auxiliary Data ** ** The following two functions may be used by scalar SQL functions to ** associate metadata with argument values. If the same value is passed to ** multiple invocations of the same SQL function during query execution, under ** some circumstances the associated metadata may be preserved. This may ** be used, for example, to add a regular-expression matching scalar ** function. The compiled version of the regular expression is stored as ** metadata associated with the SQL value passed as the regular expression ** pattern. The compiled regular expression can be reused on multiple ** invocations of the same function so that the original pattern string ** does not need to be recompiled on each invocation. ** ** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata ** associated by the sqlite3_set_auxdata() function with the Nth argument ** value to the application-defined function. ^If no metadata has been ever ** been set for the Nth argument of the function, or if the corresponding ** function parameter has changed since the meta-data was set, ** then sqlite3_get_auxdata() returns a NULL pointer. ** ** ^The sqlite3_set_auxdata() interface saves the metadata ** pointed to by its 3rd parameter as the metadata for the N-th ** argument of the application-defined function. Subsequent ** calls to sqlite3_get_auxdata() might return this data, if it has ** not been destroyed. ** ^If it is not NULL, SQLite will invoke the destructor ** function given by the 4th parameter to sqlite3_set_auxdata() on ** the metadata when the corresponding function parameter changes ** or when the SQL statement completes, whichever comes first. ** ** SQLite is free to call the destructor and drop metadata on any ** parameter of any function at any time. ^The only guarantee is that ** the destructor will be called before the metadata is dropped. ** ** ^(In practice, metadata is preserved between function calls for ** expressions that are constant at compile time. This includes literal ** values and [parameters].)^ ** ** These routines must be called from the same thread in which ** the SQL function is running. */ SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N); SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); /* ** CAPI3REF: Constants Defining Special Destructor Behavior ** ** These are special values for the destructor that is passed in as the ** final argument to routines like [sqlite3_result_blob()]. ^If the destructor ** argument is SQLITE_STATIC, it means that the content pointer is constant ** and will never change. It does not need to be destroyed. ^The ** SQLITE_TRANSIENT value means that the content will likely change in ** the near future and that SQLite should make its own private copy of ** the content before returning. ** ** The typedef is necessary to work around problems in certain ** C++ compilers. See ticket #2191. */ typedef void (*sqlite3_destructor_type)(void*); #define SQLITE_STATIC ((sqlite3_destructor_type)0) #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) /* ** CAPI3REF: Setting The Result Of An SQL Function ** ** These routines are used by the xFunc or xFinal callbacks that ** implement SQL functions and aggregates. See ** [sqlite3_create_function()] and [sqlite3_create_function16()] ** for additional information. ** ** These functions work very much like the [parameter binding] family of ** functions used to bind values to host parameters in prepared statements. ** Refer to the [SQL parameter] documentation for additional information. ** ** ^The sqlite3_result_blob() interface sets the result from ** an application-defined function to be the BLOB whose content is pointed ** to by the second parameter and which is N bytes long where N is the ** third parameter. ** ** ^The sqlite3_result_zeroblob() interfaces set the result of ** the application-defined function to be a BLOB containing all zero ** bytes and N bytes in size, where N is the value of the 2nd parameter. ** ** ^The sqlite3_result_double() interface sets the result from ** an application-defined function to be a floating point value specified ** by its 2nd argument. ** ** ^The sqlite3_result_error() and sqlite3_result_error16() functions ** cause the implemented SQL function to throw an exception. ** ^SQLite uses the string pointed to by the ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() ** as the text of an error message. ^SQLite interprets the error ** message string from sqlite3_result_error() as UTF-8. ^SQLite ** interprets the string from sqlite3_result_error16() as UTF-16 in native ** byte order. ^If the third parameter to sqlite3_result_error() ** or sqlite3_result_error16() is negative then SQLite takes as the error ** message all text up through the first zero character. ** ^If the third parameter to sqlite3_result_error() or ** sqlite3_result_error16() is non-negative then SQLite takes that many ** bytes (not characters) from the 2nd parameter as the error message. ** ^The sqlite3_result_error() and sqlite3_result_error16() ** routines make a private copy of the error message text before ** they return. Hence, the calling function can deallocate or ** modify the text after they return without harm. ** ^The sqlite3_result_error_code() function changes the error code ** returned by SQLite as a result of an error in a function. ^By default, ** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. ** ** ^The sqlite3_result_toobig() interface causes SQLite to throw an error ** indicating that a string or BLOB is too long to represent. ** ** ^The sqlite3_result_nomem() interface causes SQLite to throw an error ** indicating that a memory allocation failed. ** ** ^The sqlite3_result_int() interface sets the return value ** of the application-defined function to be the 32-bit signed integer ** value given in the 2nd argument. ** ^The sqlite3_result_int64() interface sets the return value ** of the application-defined function to be the 64-bit signed integer ** value given in the 2nd argument. ** ** ^The sqlite3_result_null() interface sets the return value ** of the application-defined function to be NULL. ** ** ^The sqlite3_result_text(), sqlite3_result_text16(), ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces ** set the return value of the application-defined function to be ** a text string which is represented as UTF-8, UTF-16 native byte order, ** UTF-16 little endian, or UTF-16 big endian, respectively. ** ^SQLite takes the text result from the application from ** the 2nd parameter of the sqlite3_result_text* interfaces. ** ^If the 3rd parameter to the sqlite3_result_text* interfaces ** is negative, then SQLite takes result text from the 2nd parameter ** through the first zero character. ** ^If the 3rd parameter to the sqlite3_result_text* interfaces ** is non-negative, then as many bytes (not characters) of the text ** pointed to by the 2nd parameter are taken as the application-defined ** function result. ** ^If the 4th parameter to the sqlite3_result_text* interfaces ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that ** function as the destructor on the text or BLOB result when it has ** finished using that result. ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite ** assumes that the text or BLOB result is in constant space and does not ** copy the content of the parameter nor call a destructor on the content ** when it has finished using that result. ** ^If the 4th parameter to the sqlite3_result_text* interfaces ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT ** then SQLite makes a copy of the result into space obtained from ** from [sqlite3_malloc()] before it returns. ** ** ^The sqlite3_result_value() interface sets the result of ** the application-defined function to be a copy the ** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The ** sqlite3_result_value() interface makes a copy of the [sqlite3_value] ** so that the [sqlite3_value] specified in the parameter may change or ** be deallocated after sqlite3_result_value() returns without harm. ** ^A [protected sqlite3_value] object may always be used where an ** [unprotected sqlite3_value] object is required, so either ** kind of [sqlite3_value] object can be used with this interface. ** ** If these routines are called from within the different thread ** than the one containing the application-defined function that received ** the [sqlite3_context] pointer, the results are undefined. */ SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); SQLITE_API void sqlite3_result_double(sqlite3_context*, double); SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int); SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int); SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*); SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*); SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int); SQLITE_API void sqlite3_result_int(sqlite3_context*, int); SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); SQLITE_API void sqlite3_result_null(sqlite3_context*); SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*); SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n); /* ** CAPI3REF: Define New Collating Sequences ** ** These functions are used to add new collation sequences to the ** [database connection] specified as the first argument. ** ** ^The name of the new collation sequence is specified as a UTF-8 string ** for sqlite3_create_collation() and sqlite3_create_collation_v2() ** and a UTF-16 string for sqlite3_create_collation16(). ^In all cases ** the name is passed as the second function argument. ** ** ^The third argument may be one of the constants [SQLITE_UTF8], ** [SQLITE_UTF16LE], or [SQLITE_UTF16BE], indicating that the user-supplied ** routine expects to be passed pointers to strings encoded using UTF-8, ** UTF-16 little-endian, or UTF-16 big-endian, respectively. ^The ** third argument might also be [SQLITE_UTF16] to indicate that the routine ** expects pointers to be UTF-16 strings in the native byte order, or the ** argument can be [SQLITE_UTF16_ALIGNED] if the ** the routine expects pointers to 16-bit word aligned strings ** of UTF-16 in the native byte order. ** ** A pointer to the user supplied routine must be passed as the fifth ** argument. ^If it is NULL, this is the same as deleting the collation ** sequence (so that SQLite cannot call it anymore). ** ^Each time the application supplied function is invoked, it is passed ** as its first parameter a copy of the void* passed as the fourth argument ** to sqlite3_create_collation() or sqlite3_create_collation16(). ** ** ^The remaining arguments to the application-supplied routine are two strings, ** each represented by a (length, data) pair and encoded in the encoding ** that was passed as the third argument when the collation sequence was ** registered. The application defined collation routine should ** return negative, zero or positive if the first string is less than, ** equal to, or greater than the second string. i.e. (STRING1 - STRING2). ** ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() ** except that it takes an extra argument which is a destructor for ** the collation. ^The destructor is called when the collation is ** destroyed and is passed a copy of the fourth parameter void* pointer ** of the sqlite3_create_collation_v2(). ** ^Collations are destroyed when they are overridden by later calls to the ** collation creation functions or when the [database connection] is closed ** using [sqlite3_close()]. ** ** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. */ SQLITE_API int sqlite3_create_collation( sqlite3*, const char *zName, int eTextRep, void*, int(*xCompare)(void*,int,const void*,int,const void*) ); SQLITE_API int sqlite3_create_collation_v2( sqlite3*, const char *zName, int eTextRep, void*, int(*xCompare)(void*,int,const void*,int,const void*), void(*xDestroy)(void*) ); SQLITE_API int sqlite3_create_collation16( sqlite3*, const void *zName, int eTextRep, void*, int(*xCompare)(void*,int,const void*,int,const void*) ); /* ** CAPI3REF: Collation Needed Callbacks ** ** ^To avoid having to register all collation sequences before a database ** can be used, a single callback function may be registered with the ** [database connection] to be invoked whenever an undefined collation ** sequence is required. ** ** ^If the function is registered using the sqlite3_collation_needed() API, ** then it is passed the names of undefined collation sequences as strings ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, ** the names are passed as UTF-16 in machine native byte order. ** ^A call to either function replaces the existing collation-needed callback. ** ** ^(When the callback is invoked, the first argument passed is a copy ** of the second argument to sqlite3_collation_needed() or ** sqlite3_collation_needed16(). The second argument is the database ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation ** sequence function required. The fourth parameter is the name of the ** required collation sequence.)^ ** ** The callback function should register the desired collation using ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or ** [sqlite3_create_collation_v2()]. */ SQLITE_API int sqlite3_collation_needed( sqlite3*, void*, void(*)(void*,sqlite3*,int eTextRep,const char*) ); SQLITE_API int sqlite3_collation_needed16( sqlite3*, void*, void(*)(void*,sqlite3*,int eTextRep,const void*) ); #ifdef SQLITE_HAS_CODEC /* ** Specify the key for an encrypted database. This routine should be ** called right after sqlite3_open(). ** ** The code to implement this API is not available in the public release ** of SQLite. */ SQLITE_API int sqlite3_key( sqlite3 *db, /* Database to be rekeyed */ const void *pKey, int nKey /* The key */ ); /* ** Change the key on an open database. If the current database is not ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the ** database is decrypted. ** ** The code to implement this API is not available in the public release ** of SQLite. */ SQLITE_API int sqlite3_rekey( sqlite3 *db, /* Database to be rekeyed */ const void *pKey, int nKey /* The new key */ ); /* ** Specify the activation key for a SEE database. Unless ** activated, none of the SEE routines will work. */ SQLITE_API void sqlite3_activate_see( const char *zPassPhrase /* Activation phrase */ ); #endif #ifdef SQLITE_ENABLE_CEROD /* ** Specify the activation key for a CEROD database. Unless ** activated, none of the CEROD routines will work. */ SQLITE_API void sqlite3_activate_cerod( const char *zPassPhrase /* Activation phrase */ ); #endif /* ** CAPI3REF: Suspend Execution For A Short Time ** ** ^The sqlite3_sleep() function causes the current thread to suspend execution ** for at least a number of milliseconds specified in its parameter. ** ** ^If the operating system does not support sleep requests with ** millisecond time resolution, then the time will be rounded up to ** the nearest second. ^The number of milliseconds of sleep actually ** requested from the operating system is returned. ** ** ^SQLite implements this interface by calling the xSleep() ** method of the default [sqlite3_vfs] object. */ SQLITE_API int sqlite3_sleep(int); /* ** CAPI3REF: Name Of The Folder Holding Temporary Files ** ** ^(If this global variable is made to point to a string which is ** the name of a folder (a.k.a. directory), then all temporary files ** created by SQLite when using a built-in [sqlite3_vfs | VFS] ** will be placed in that directory.)^ ^If this variable ** is a NULL pointer, then SQLite performs a search for an appropriate ** temporary file directory. ** ** It is not safe to read or modify this variable in more than one ** thread at a time. It is not safe to read or modify this variable ** if a [database connection] is being used at the same time in a separate ** thread. ** It is intended that this variable be set once ** as part of process initialization and before any SQLite interface ** routines have been called and that this variable remain unchanged ** thereafter. ** ** ^The [temp_store_directory pragma] may modify this variable and cause ** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, ** the [temp_store_directory pragma] always assumes that any string ** that this variable points to is held in memory obtained from ** [sqlite3_malloc] and the pragma may attempt to free that memory ** using [sqlite3_free]. ** Hence, if this variable is modified directly, either it should be ** made NULL or made to point to memory obtained from [sqlite3_malloc] ** or else the use of the [temp_store_directory pragma] should be avoided. */ SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory; /* ** CAPI3REF: Test For Auto-Commit Mode ** KEYWORDS: {autocommit mode} ** ** ^The sqlite3_get_autocommit() interface returns non-zero or ** zero if the given database connection is or is not in autocommit mode, ** respectively. ^Autocommit mode is on by default. ** ^Autocommit mode is disabled by a [BEGIN] statement. ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. ** ** If certain kinds of errors occur on a statement within a multi-statement ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the ** transaction might be rolled back automatically. The only way to ** find out whether SQLite automatically rolled back the transaction after ** an error is to use this function. ** ** If another thread changes the autocommit status of the database ** connection while this routine is running, then the return value ** is undefined. */ SQLITE_API int sqlite3_get_autocommit(sqlite3*); /* ** CAPI3REF: Find The Database Handle Of A Prepared Statement ** ** ^The sqlite3_db_handle interface returns the [database connection] handle ** to which a [prepared statement] belongs. ^The [database connection] ** returned by sqlite3_db_handle is the same [database connection] ** that was the first argument ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to ** create the statement in the first place. */ SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*); /* ** CAPI3REF: Find the next prepared statement ** ** ^This interface returns a pointer to the next [prepared statement] after ** pStmt associated with the [database connection] pDb. ^If pStmt is NULL ** then this interface returns a pointer to the first prepared statement ** associated with the database connection pDb. ^If no prepared statement ** satisfies the conditions of this routine, it returns NULL. ** ** The [database connection] pointer D in a call to ** [sqlite3_next_stmt(D,S)] must refer to an open database ** connection and in particular must not be a NULL pointer. */ SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); /* ** CAPI3REF: Commit And Rollback Notification Callbacks ** ** ^The sqlite3_commit_hook() interface registers a callback ** function to be invoked whenever a transaction is [COMMIT | committed]. ** ^Any callback set by a previous call to sqlite3_commit_hook() ** for the same database connection is overridden. ** ^The sqlite3_rollback_hook() interface registers a callback ** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. ** ^Any callback set by a previous call to sqlite3_rollback_hook() ** for the same database connection is overridden. ** ^The pArg argument is passed through to the callback. ** ^If the callback on a commit hook function returns non-zero, ** then the commit is converted into a rollback. ** ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions ** return the P argument from the previous call of the same function ** on the same [database connection] D, or NULL for ** the first call for each function on D. ** ** The callback implementation must not do anything that will modify ** the database connection that invoked the callback. Any actions ** to modify the database connection must be deferred until after the ** completion of the [sqlite3_step()] call that triggered the commit ** or rollback hook in the first place. ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their ** database connections for the meaning of "modify" in this paragraph. ** ** ^Registering a NULL function disables the callback. ** ** ^When the commit hook callback routine returns zero, the [COMMIT] ** operation is allowed to continue normally. ^If the commit hook ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. ** ^The rollback hook is invoked on a rollback that results from a commit ** hook returning non-zero, just as it would be with any other rollback. ** ** ^For the purposes of this API, a transaction is said to have been ** rolled back if an explicit "ROLLBACK" statement is executed, or ** an error or constraint causes an implicit rollback to occur. ** ^The rollback callback is not invoked if a transaction is ** automatically rolled back because the database connection is closed. ** ** See also the [sqlite3_update_hook()] interface. */ SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); /* ** CAPI3REF: Data Change Notification Callbacks ** ** ^The sqlite3_update_hook() interface registers a callback function ** with the [database connection] identified by the first argument ** to be invoked whenever a row is updated, inserted or deleted. ** ^Any callback set by a previous call to this function ** for the same database connection is overridden. ** ** ^The second argument is a pointer to the function to invoke when a ** row is updated, inserted or deleted. ** ^The first argument to the callback is a copy of the third argument ** to sqlite3_update_hook(). ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], ** or [SQLITE_UPDATE], depending on the operation that caused the callback ** to be invoked. ** ^The third and fourth arguments to the callback contain pointers to the ** database and table name containing the affected row. ** ^The final callback parameter is the [rowid] of the row. ** ^In the case of an update, this is the [rowid] after the update takes place. ** ** ^(The update hook is not invoked when internal system tables are ** modified (i.e. sqlite_master and sqlite_sequence).)^ ** ** ^In the current implementation, the update hook ** is not invoked when duplication rows are deleted because of an ** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook ** invoked when rows are deleted using the [truncate optimization]. ** The exceptions defined in this paragraph might change in a future ** release of SQLite. ** ** The update hook implementation must not do anything that will modify ** the database connection that invoked the update hook. Any actions ** to modify the database connection must be deferred until after the ** completion of the [sqlite3_step()] call that triggered the update hook. ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their ** database connections for the meaning of "modify" in this paragraph. ** ** ^The sqlite3_update_hook(D,C,P) function ** returns the P argument from the previous call ** on the same [database connection] D, or NULL for ** the first call on D. ** ** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] ** interfaces. */ SQLITE_API void *sqlite3_update_hook( sqlite3*, void(*)(void *,int ,char const *,char const *,sqlite3_int64), void* ); /* ** CAPI3REF: Enable Or Disable Shared Pager Cache ** KEYWORDS: {shared cache} ** ** ^(This routine enables or disables the sharing of the database cache ** and schema data structures between [database connection | connections] ** to the same database. Sharing is enabled if the argument is true ** and disabled if the argument is false.)^ ** ** ^Cache sharing is enabled and disabled for an entire process. ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, ** sharing was enabled or disabled for each thread separately. ** ** ^(The cache sharing mode set by this interface effects all subsequent ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. ** Existing database connections continue use the sharing mode ** that was in effect at the time they were opened.)^ ** ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled ** successfully. An [error code] is returned otherwise.)^ ** ** ^Shared cache is disabled by default. But this might change in ** future releases of SQLite. Applications that care about shared ** cache setting should set it explicitly. ** ** See Also: [SQLite Shared-Cache Mode] */ SQLITE_API int sqlite3_enable_shared_cache(int); /* ** CAPI3REF: Attempt To Free Heap Memory ** ** ^The sqlite3_release_memory() interface attempts to free N bytes ** of heap memory by deallocating non-essential memory allocations ** held by the database library. Memory used to cache database ** pages to improve performance is an example of non-essential memory. ** ^sqlite3_release_memory() returns the number of bytes actually freed, ** which might be more or less than the amount requested. */ SQLITE_API int sqlite3_release_memory(int); /* ** CAPI3REF: Impose A Limit On Heap Size ** ** ^The sqlite3_soft_heap_limit() interface places a "soft" limit ** on the amount of heap memory that may be allocated by SQLite. ** ^If an internal allocation is requested that would exceed the ** soft heap limit, [sqlite3_release_memory()] is invoked one or ** more times to free up some space before the allocation is performed. ** ** ^The limit is called "soft" because if [sqlite3_release_memory()] ** cannot free sufficient memory to prevent the limit from being exceeded, ** the memory is allocated anyway and the current operation proceeds. ** ** ^A negative or zero value for N means that there is no soft heap limit and ** [sqlite3_release_memory()] will only be called when memory is exhausted. ** ^The default value for the soft heap limit is zero. ** ** ^(SQLite makes a best effort to honor the soft heap limit. ** But if the soft heap limit cannot be honored, execution will ** continue without error or notification.)^ This is why the limit is ** called a "soft" limit. It is advisory only. ** ** Prior to SQLite version 3.5.0, this routine only constrained the memory ** allocated by a single thread - the same thread in which this routine ** runs. Beginning with SQLite version 3.5.0, the soft heap limit is ** applied to all threads. The value specified for the soft heap limit ** is an upper bound on the total memory allocation for all threads. In ** version 3.5.0 there is no mechanism for limiting the heap usage for ** individual threads. */ SQLITE_API void sqlite3_soft_heap_limit(int); /* ** CAPI3REF: Extract Metadata About A Column Of A Table ** ** ^This routine returns metadata about a specific column of a specific ** database table accessible using the [database connection] handle ** passed as the first function argument. ** ** ^The column is identified by the second, third and fourth parameters to ** this function. ^The second parameter is either the name of the database ** (i.e. "main", "temp", or an attached database) containing the specified ** table or NULL. ^If it is NULL, then all attached databases are searched ** for the table using the same algorithm used by the database engine to ** resolve unqualified table references. ** ** ^The third and fourth parameters to this function are the table and column ** name of the desired column, respectively. Neither of these parameters ** may be NULL. ** ** ^Metadata is returned by writing to the memory locations passed as the 5th ** and subsequent parameters to this function. ^Any of these arguments may be ** NULL, in which case the corresponding element of metadata is omitted. ** ** ^(
** **
Parameter Output
Type 		Description ** **
5th const char* Data type **
6th const char* Name of default collation sequence **
7th int True if column has a NOT NULL constraint **
8th int True if column is part of the PRIMARY KEY **
9th int True if column is [AUTOINCREMENT] **
**
)^ ** ** ^The memory pointed to by the character pointers returned for the ** declaration type and collation sequence is valid only until the next ** call to any SQLite API function. ** ** ^If the specified table is actually a view, an [error code] is returned. ** ** ^If the specified column is "rowid", "oid" or "_rowid_" and an ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output ** parameters are set for the explicitly declared column. ^(If there is no ** explicitly declared [INTEGER PRIMARY KEY] column, then the output ** parameters are set as follows: ** ** 
**     data type: "INTEGER"
**     collation sequence: "BINARY"
**     not null: 0
**     primary key: 1
**     auto increment: 0
**
)^ ** ** ^(This function may load one or more schemas from database files. If an ** error occurs during this process, or if the requested table or column ** cannot be found, an [error code] is returned and an error message left ** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ ** ** ^This API is only available if the library was compiled with the ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. */ SQLITE_API int sqlite3_table_column_metadata( sqlite3 *db, /* Connection handle */ const char *zDbName, /* Database name or NULL */ const char *zTableName, /* Table name */ const char *zColumnName, /* Column name */ char const **pzDataType, /* OUTPUT: Declared data type */ char const **pzCollSeq, /* OUTPUT: Collation sequence name */ int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ int *pPrimaryKey, /* OUTPUT: True if column part of PK */ int *pAutoinc /* OUTPUT: True if column is auto-increment */ ); /* ** CAPI3REF: Load An Extension ** ** ^This interface loads an SQLite extension library from the named file. ** ** ^The sqlite3_load_extension() interface attempts to load an ** SQLite extension library contained in the file zFile. ** ** ^The entry point is zProc. ** ^zProc may be 0, in which case the name of the entry point ** defaults to "sqlite3_extension_init". ** ^The sqlite3_load_extension() interface returns ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. ** ^If an error occurs and pzErrMsg is not 0, then the ** [sqlite3_load_extension()] interface shall attempt to ** fill *pzErrMsg with error message text stored in memory ** obtained from [sqlite3_malloc()]. The calling function ** should free this memory by calling [sqlite3_free()]. ** ** ^Extension loading must be enabled using ** [sqlite3_enable_load_extension()] prior to calling this API, ** otherwise an error will be returned. ** ** See also the [load_extension() SQL function]. */ SQLITE_API int sqlite3_load_extension( sqlite3 *db, /* Load the extension into this database connection */ const char *zFile, /* Name of the shared library containing extension */ const char *zProc, /* Entry point. Derived from zFile if 0 */ char **pzErrMsg /* Put error message here if not 0 */ ); /* ** CAPI3REF: Enable Or Disable Extension Loading ** ** ^So as not to open security holes in older applications that are ** unprepared to deal with extension loading, and as a means of disabling ** extension loading while evaluating user-entered SQL, the following API ** is provided to turn the [sqlite3_load_extension()] mechanism on and off. ** ** ^Extension loading is off by default. See ticket #1863. ** ^Call the sqlite3_enable_load_extension() routine with onoff==1 ** to turn extension loading on and call it with onoff==0 to turn ** it back off again. */ SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff); /* ** CAPI3REF: Automatically Load An Extensions ** ** ^This API can be invoked at program startup in order to register ** one or more statically linked extensions that will be available ** to all new [database connections]. ** ** ^(This routine stores a pointer to the extension entry point ** in an array that is obtained from [sqlite3_malloc()]. That memory ** is deallocated by [sqlite3_reset_auto_extension()].)^ ** ** ^This function registers an extension entry point that is ** automatically invoked whenever a new [database connection] ** is opened using [sqlite3_open()], [sqlite3_open16()], ** or [sqlite3_open_v2()]. ** ^Duplicate extensions are detected so calling this routine ** multiple times with the same extension is harmless. ** ^Automatic extensions apply across all threads. */ SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void)); /* ** CAPI3REF: Reset Automatic Extension Loading ** ** ^(This function disables all previously registered automatic ** extensions. It undoes the effect of all prior ** [sqlite3_auto_extension()] calls.)^ ** ** ^This function disables automatic extensions in all threads. */ SQLITE_API void sqlite3_reset_auto_extension(void); /* ** The interface to the virtual-table mechanism is currently considered ** to be experimental. The interface might change in incompatible ways. ** If this is a problem for you, do not use the interface at this time. ** ** When the virtual-table mechanism stabilizes, we will declare the ** interface fixed, support it indefinitely, and remove this comment. */ /* ** Structures used by the virtual table interface */ typedef struct sqlite3_vtab sqlite3_vtab; typedef struct sqlite3_index_info sqlite3_index_info; typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; typedef struct sqlite3_module sqlite3_module; /* ** CAPI3REF: Virtual Table Object ** KEYWORDS: sqlite3_module {virtual table module} ** ** This structure, sometimes called a a "virtual table module", ** defines the implementation of a [virtual tables]. ** This structure consists mostly of methods for the module. ** ** ^A virtual table module is created by filling in a persistent ** instance of this structure and passing a pointer to that instance ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. ** ^The registration remains valid until it is replaced by a different ** module or until the [database connection] closes. The content ** of this structure must not change while it is registered with ** any database connection. */ struct sqlite3_module { int iVersion; int (*xCreate)(sqlite3*, void *pAux, int argc, const char *const*argv, sqlite3_vtab **ppVTab, char**); int (*xConnect)(sqlite3*, void *pAux, int argc, const char *const*argv, sqlite3_vtab **ppVTab, char**); int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); int (*xDisconnect)(sqlite3_vtab *pVTab); int (*xDestroy)(sqlite3_vtab *pVTab); int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); int (*xClose)(sqlite3_vtab_cursor*); int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, int argc, sqlite3_value **argv); int (*xNext)(sqlite3_vtab_cursor*); int (*xEof)(sqlite3_vtab_cursor*); int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); int (*xBegin)(sqlite3_vtab *pVTab); int (*xSync)(sqlite3_vtab *pVTab); int (*xCommit)(sqlite3_vtab *pVTab); int (*xRollback)(sqlite3_vtab *pVTab); int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), void **ppArg); int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); }; /* ** CAPI3REF: Virtual Table Indexing Information ** KEYWORDS: sqlite3_index_info ** ** The sqlite3_index_info structure and its substructures is used to ** pass information into and receive the reply from the [xBestIndex] ** method of a [virtual table module]. The fields under **Inputs** are the ** inputs to xBestIndex and are read-only. xBestIndex inserts its ** results into the **Outputs** fields. ** ** ^(The aConstraint[] array records WHERE clause constraints of the form: ** ** 
column OP expr
** ** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is ** stored in aConstraint[].op.)^ ^(The index of the column is stored in ** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the ** expr on the right-hand side can be evaluated (and thus the constraint ** is usable) and false if it cannot.)^ ** ** ^The optimizer automatically inverts terms of the form "expr OP column" ** and makes other simplifications to the WHERE clause in an attempt to ** get as many WHERE clause terms into the form shown above as possible. ** ^The aConstraint[] array only reports WHERE clause terms that are ** relevant to the particular virtual table being queried. ** ** ^Information about the ORDER BY clause is stored in aOrderBy[]. ** ^Each term of aOrderBy records a column of the ORDER BY clause. ** ** The [xBestIndex] method must fill aConstraintUsage[] with information ** about what parameters to pass to xFilter. ^If argvIndex>0 then ** the right-hand side of the corresponding aConstraint[] is evaluated ** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit ** is true, then the constraint is assumed to be fully handled by the ** virtual table and is not checked again by SQLite.)^ ** ** ^The idxNum and idxPtr values are recorded and passed into the ** [xFilter] method. ** ^[sqlite3_free()] is used to free idxPtr if and only if ** needToFreeIdxPtr is true. ** ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in ** the correct order to satisfy the ORDER BY clause so that no separate ** sorting step is required. ** ** ^The estimatedCost value is an estimate of the cost of doing the ** particular lookup. A full scan of a table with N entries should have ** a cost of N. A binary search of a table of N entries should have a ** cost of approximately log(N). */ struct sqlite3_index_info { /* Inputs */ int nConstraint; /* Number of entries in aConstraint */ struct sqlite3_index_constraint { int iColumn; /* Column on left-hand side of constraint */ unsigned char op; /* Constraint operator */ unsigned char usable; /* True if this constraint is usable */ int iTermOffset; /* Used internally - xBestIndex should ignore */ } *aConstraint; /* Table of WHERE clause constraints */ int nOrderBy; /* Number of terms in the ORDER BY clause */ struct sqlite3_index_orderby { int iColumn; /* Column number */ unsigned char desc; /* True for DESC. False for ASC. */ } *aOrderBy; /* The ORDER BY clause */ /* Outputs */ struct sqlite3_index_constraint_usage { int argvIndex; /* if >0, constraint is part of argv to xFilter */ unsigned char omit; /* Do not code a test for this constraint */ } *aConstraintUsage; int idxNum; /* Number used to identify the index */ char *idxStr; /* String, possibly obtained from sqlite3_malloc */ int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ int orderByConsumed; /* True if output is already ordered */ double estimatedCost; /* Estimated cost of using this index */ }; #define SQLITE_INDEX_CONSTRAINT_EQ 2 #define SQLITE_INDEX_CONSTRAINT_GT 4 #define SQLITE_INDEX_CONSTRAINT_LE 8 #define SQLITE_INDEX_CONSTRAINT_LT 16 #define SQLITE_INDEX_CONSTRAINT_GE 32 #define SQLITE_INDEX_CONSTRAINT_MATCH 64 /* ** CAPI3REF: Register A Virtual Table Implementation ** ** ^These routines are used to register a new [virtual table module] name. ** ^Module names must be registered before ** creating a new [virtual table] using the module and before using a ** preexisting [virtual table] for the module. ** ** ^The module name is registered on the [database connection] specified ** by the first parameter. ^The name of the module is given by the ** second parameter. ^The third parameter is a pointer to ** the implementation of the [virtual table module]. ^The fourth ** parameter is an arbitrary client data pointer that is passed through ** into the [xCreate] and [xConnect] methods of the virtual table module ** when a new virtual table is be being created or reinitialized. ** ** ^The sqlite3_create_module_v2() interface has a fifth parameter which ** is a pointer to a destructor for the pClientData. ^SQLite will ** invoke the destructor function (if it is not NULL) when SQLite ** no longer needs the pClientData pointer. ^The sqlite3_create_module() ** interface is equivalent to sqlite3_create_module_v2() with a NULL ** destructor. */ SQLITE_API int sqlite3_create_module( sqlite3 *db, /* SQLite connection to register module with */ const char *zName, /* Name of the module */ const sqlite3_module *p, /* Methods for the module */ void *pClientData /* Client data for xCreate/xConnect */ ); SQLITE_API int sqlite3_create_module_v2( sqlite3 *db, /* SQLite connection to register module with */ const char *zName, /* Name of the module */ const sqlite3_module *p, /* Methods for the module */ void *pClientData, /* Client data for xCreate/xConnect */ void(*xDestroy)(void*) /* Module destructor function */ ); /* ** CAPI3REF: Virtual Table Instance Object ** KEYWORDS: sqlite3_vtab ** ** Every [virtual table module] implementation uses a subclass ** of this object to describe a particular instance ** of the [virtual table]. Each subclass will ** be tailored to the specific needs of the module implementation. ** The purpose of this superclass is to define certain fields that are ** common to all module implementations. ** ** ^Virtual tables methods can set an error message by assigning a ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should ** take care that any prior string is freed by a call to [sqlite3_free()] ** prior to assigning a new string to zErrMsg. ^After the error message ** is delivered up to the client application, the string will be automatically ** freed by sqlite3_free() and the zErrMsg field will be zeroed. */ struct sqlite3_vtab { const sqlite3_module *pModule; /* The module for this virtual table */ int nRef; /* NO LONGER USED */ char *zErrMsg; /* Error message from sqlite3_mprintf() */ /* Virtual table implementations will typically add additional fields */ }; /* ** CAPI3REF: Virtual Table Cursor Object ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} ** ** Every [virtual table module] implementation uses a subclass of the ** following structure to describe cursors that point into the ** [virtual table] and are used ** to loop through the virtual table. Cursors are created using the ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed ** by the [sqlite3_module.xClose | xClose] method. Cursors are used ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods ** of the module. Each module implementation will define ** the content of a cursor structure to suit its own needs. ** ** This superclass exists in order to define fields of the cursor that ** are common to all implementations. */ struct sqlite3_vtab_cursor { sqlite3_vtab *pVtab; /* Virtual table of this cursor */ /* Virtual table implementations will typically add additional fields */ }; /* ** CAPI3REF: Declare The Schema Of A Virtual Table ** ** ^The [xCreate] and [xConnect] methods of a ** [virtual table module] call this interface ** to declare the format (the names and datatypes of the columns) of ** the virtual tables they implement. */ SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL); /* ** CAPI3REF: Overload A Function For A Virtual Table ** ** ^(Virtual tables can provide alternative implementations of functions ** using the [xFindFunction] method of the [virtual table module]. ** But global versions of those functions ** must exist in order to be overloaded.)^ ** ** ^(This API makes sure a global version of a function with a particular ** name and number of parameters exists. If no such function exists ** before this API is called, a new function is created.)^ ^The implementation ** of the new function always causes an exception to be thrown. So ** the new function is not good for anything by itself. Its only ** purpose is to be a placeholder function that can be overloaded ** by a [virtual table]. */ SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); /* ** The interface to the virtual-table mechanism defined above (back up ** to a comment remarkably similar to this one) is currently considered ** to be experimental. The interface might change in incompatible ways. ** If this is a problem for you, do not use the interface at this time. ** ** When the virtual-table mechanism stabilizes, we will declare the ** interface fixed, support it indefinitely, and remove this comment. */ /* ** CAPI3REF: A Handle To An Open BLOB ** KEYWORDS: {BLOB handle} {BLOB handles} ** ** An instance of this object represents an open BLOB on which ** [sqlite3_blob_open | incremental BLOB I/O] can be performed. ** ^Objects of this type are created by [sqlite3_blob_open()] ** and destroyed by [sqlite3_blob_close()]. ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces ** can be used to read or write small subsections of the BLOB. ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. */ typedef struct sqlite3_blob sqlite3_blob; /* ** CAPI3REF: Open A BLOB For Incremental I/O ** ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located ** in row iRow, column zColumn, table zTable in database zDb; ** in other words, the same BLOB that would be selected by: ** ** 
**     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
**
)^ ** ** ^If the flags parameter is non-zero, then the BLOB is opened for read ** and write access. ^If it is zero, the BLOB is opened for read access. ** ^It is not possible to open a column that is part of an index or primary ** key for writing. ^If [foreign key constraints] are enabled, it is ** not possible to open a column that is part of a [child key] for writing. ** ** ^Note that the database name is not the filename that contains ** the database but rather the symbolic name of the database that ** appears after the AS keyword when the database is connected using [ATTACH]. ** ^For the main database file, the database name is "main". ** ^For TEMP tables, the database name is "temp". ** ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written ** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set ** to be a null pointer.)^ ** ^This function sets the [database connection] error code and message ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related ** functions. ^Note that the *ppBlob variable is always initialized in a ** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob ** regardless of the success or failure of this routine. ** ** ^(If the row that a BLOB handle points to is modified by an ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects ** then the BLOB handle is marked as "expired". ** This is true if any column of the row is changed, even a column ** other than the one the BLOB handle is open on.)^ ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for ** a expired BLOB handle fail with an return code of [SQLITE_ABORT]. ** ^(Changes written into a BLOB prior to the BLOB expiring are not ** rolled back by the expiration of the BLOB. Such changes will eventually ** commit if the transaction continues to completion.)^ ** ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of ** the opened blob. ^The size of a blob may not be changed by this ** interface. Use the [UPDATE] SQL command to change the size of a ** blob. ** ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces ** and the built-in [zeroblob] SQL function can be used, if desired, ** to create an empty, zero-filled blob in which to read or write using ** this interface. ** ** To avoid a resource leak, every open [BLOB handle] should eventually ** be released by a call to [sqlite3_blob_close()]. */ SQLITE_API int sqlite3_blob_open( sqlite3*, const char *zDb, const char *zTable, const char *zColumn, sqlite3_int64 iRow, int flags, sqlite3_blob **ppBlob ); /* ** CAPI3REF: Close A BLOB Handle ** ** ^Closes an open [BLOB handle]. ** ** ^Closing a BLOB shall cause the current transaction to commit ** if there are no other BLOBs, no pending prepared statements, and the ** database connection is in [autocommit mode]. ** ^If any writes were made to the BLOB, they might be held in cache ** until the close operation if they will fit. ** ** ^(Closing the BLOB often forces the changes ** out to disk and so if any I/O errors occur, they will likely occur ** at the time when the BLOB is closed. Any errors that occur during ** closing are reported as a non-zero return value.)^ ** ** ^(The BLOB is closed unconditionally. Even if this routine returns ** an error code, the BLOB is still closed.)^ ** ** ^Calling this routine with a null pointer (such as would be returned ** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. */ SQLITE_API int sqlite3_blob_close(sqlite3_blob *); /* ** CAPI3REF: Return The Size Of An Open BLOB ** ** ^Returns the size in bytes of the BLOB accessible via the ** successfully opened [BLOB handle] in its only argument. ^The ** incremental blob I/O routines can only read or overwriting existing ** blob content; they cannot change the size of a blob. ** ** This routine only works on a [BLOB handle] which has been created ** by a prior successful call to [sqlite3_blob_open()] and which has not ** been closed by [sqlite3_blob_close()]. Passing any other pointer in ** to this routine results in undefined and probably undesirable behavior. */ SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *); /* ** CAPI3REF: Read Data From A BLOB Incrementally ** ** ^(This function is used to read data from an open [BLOB handle] into a ** caller-supplied buffer. N bytes of data are copied into buffer Z ** from the open BLOB, starting at offset iOffset.)^ ** ** ^If offset iOffset is less than N bytes from the end of the BLOB, ** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is ** less than zero, [SQLITE_ERROR] is returned and no data is read. ** ^The size of the blob (and hence the maximum value of N+iOffset) ** can be determined using the [sqlite3_blob_bytes()] interface. ** ** ^An attempt to read from an expired [BLOB handle] fails with an ** error code of [SQLITE_ABORT]. ** ** ^(On success, sqlite3_blob_read() returns SQLITE_OK. ** Otherwise, an [error code] or an [extended error code] is returned.)^ ** ** This routine only works on a [BLOB handle] which has been created ** by a prior successful call to [sqlite3_blob_open()] and which has not ** been closed by [sqlite3_blob_close()]. Passing any other pointer in ** to this routine results in undefined and probably undesirable behavior. ** ** See also: [sqlite3_blob_write()]. */ SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); /* ** CAPI3REF: Write Data Into A BLOB Incrementally ** ** ^This function is used to write data into an open [BLOB handle] from a ** caller-supplied buffer. ^N bytes of data are copied from the buffer Z ** into the open BLOB, starting at offset iOffset. ** ** ^If the [BLOB handle] passed as the first argument was not opened for ** writing (the flags parameter to [sqlite3_blob_open()] was zero), ** this function returns [SQLITE_READONLY]. ** ** ^This function may only modify the contents of the BLOB; it is ** not possible to increase the size of a BLOB using this API. ** ^If offset iOffset is less than N bytes from the end of the BLOB, ** [SQLITE_ERROR] is returned and no data is written. ^If N is ** less than zero [SQLITE_ERROR] is returned and no data is written. ** The size of the BLOB (and hence the maximum value of N+iOffset) ** can be determined using the [sqlite3_blob_bytes()] interface. ** ** ^An attempt to write to an expired [BLOB handle] fails with an ** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred ** before the [BLOB handle] expired are not rolled back by the ** expiration of the handle, though of course those changes might ** have been overwritten by the statement that expired the BLOB handle ** or by other independent statements. ** ** ^(On success, sqlite3_blob_write() returns SQLITE_OK. ** Otherwise, an [error code] or an [extended error code] is returned.)^ ** ** This routine only works on a [BLOB handle] which has been created ** by a prior successful call to [sqlite3_blob_open()] and which has not ** been closed by [sqlite3_blob_close()]. Passing any other pointer in ** to this routine results in undefined and probably undesirable behavior. ** ** See also: [sqlite3_blob_read()]. */ SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); /* ** CAPI3REF: Virtual File System Objects ** ** A virtual filesystem (VFS) is an [sqlite3_vfs] object ** that SQLite uses to interact ** with the underlying operating system. Most SQLite builds come with a ** single default VFS that is appropriate for the host computer. ** New VFSes can be registered and existing VFSes can be unregistered. ** The following interfaces are provided. ** ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. ** ^Names are case sensitive. ** ^Names are zero-terminated UTF-8 strings. ** ^If there is no match, a NULL pointer is returned. ** ^If zVfsName is NULL then the default VFS is returned. ** ** ^New VFSes are registered with sqlite3_vfs_register(). ** ^Each new VFS becomes the default VFS if the makeDflt flag is set. ** ^The same VFS can be registered multiple times without injury. ** ^To make an existing VFS into the default VFS, register it again ** with the makeDflt flag set. If two different VFSes with the ** same name are registered, the behavior is undefined. If a ** VFS is registered with a name that is NULL or an empty string, ** then the behavior is undefined. ** ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. ** ^(If the default VFS is unregistered, another VFS is chosen as ** the default. The choice for the new VFS is arbitrary.)^ */ SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*); /* ** CAPI3REF: Mutexes ** ** The SQLite core uses these routines for thread ** synchronization. Though they are intended for internal ** use by SQLite, code that links against SQLite is ** permitted to use any of these routines. ** ** The SQLite source code contains multiple implementations ** of these mutex routines. An appropriate implementation ** is selected automatically at compile-time. ^(The following ** implementations are available in the SQLite core: ** ** )^ ** ** ^The SQLITE_MUTEX_NOOP implementation is a set of routines ** that does no real locking and is appropriate for use in ** a single-threaded application. ^The SQLITE_MUTEX_OS2, ** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations ** are appropriate for use on OS/2, Unix, and Windows. ** ** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex ** implementation is included with the library. In this case the ** application must supply a custom mutex implementation using the ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function ** before calling sqlite3_initialize() or any other public sqlite3_ ** function that calls sqlite3_initialize().)^ ** ** ^The sqlite3_mutex_alloc() routine allocates a new ** mutex and returns a pointer to it. ^If it returns NULL ** that means that a mutex could not be allocated. ^SQLite ** will unwind its stack and return an error. ^(The argument ** to sqlite3_mutex_alloc() is one of these integer constants: ** ** )^ ** ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) ** cause sqlite3_mutex_alloc() to create ** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE ** is used but not necessarily so when SQLITE_MUTEX_FAST is used. ** The mutex implementation does not need to make a distinction ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does ** not want to. ^SQLite will only request a recursive mutex in ** cases where it really needs one. ^If a faster non-recursive mutex ** implementation is available on the host platform, the mutex subsystem ** might return such a mutex in response to SQLITE_MUTEX_FAST. ** ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return ** a pointer to a static preexisting mutex. ^Six static mutexes are ** used by the current version of SQLite. Future versions of SQLite ** may add additional static mutexes. Static mutexes are for internal ** use by SQLite only. Applications that use SQLite mutexes should ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or ** SQLITE_MUTEX_RECURSIVE. ** ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() ** returns a different mutex on every call. ^But for the static ** mutex types, the same mutex is returned on every call that has ** the same type number. ** ** ^The sqlite3_mutex_free() routine deallocates a previously ** allocated dynamic mutex. ^SQLite is careful to deallocate every ** dynamic mutex that it allocates. The dynamic mutexes must not be in ** use when they are deallocated. Attempting to deallocate a static ** mutex results in undefined behavior. ^SQLite never deallocates ** a static mutex. ** ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt ** to enter a mutex. ^If another thread is already within the mutex, ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return ** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] ** upon successful entry. ^(Mutexes created using ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. ** In such cases the, ** mutex must be exited an equal number of times before another thread ** can enter.)^ ^(If the same thread tries to enter any other ** kind of mutex more than once, the behavior is undefined. ** SQLite will never exhibit ** such behavior in its own use of mutexes.)^ ** ** ^(Some systems (for example, Windows 95) do not support the operation ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() ** will always return SQLITE_BUSY. The SQLite core only ever uses ** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ ** ** ^The sqlite3_mutex_leave() routine exits a mutex that was ** previously entered by the same thread. ^(The behavior ** is undefined if the mutex is not currently entered by the ** calling thread or is not currently allocated. SQLite will ** never do either.)^ ** ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or ** sqlite3_mutex_leave() is a NULL pointer, then all three routines ** behave as no-ops. ** ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. */ SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int); SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*); SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*); SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*); SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*); /* ** CAPI3REF: Mutex Methods Object ** ** An instance of this structure defines the low-level routines ** used to allocate and use mutexes. ** ** Usually, the default mutex implementations provided by SQLite are ** sufficient, however the user has the option of substituting a custom ** implementation for specialized deployments or systems for which SQLite ** does not provide a suitable implementation. In this case, the user ** creates and populates an instance of this structure to pass ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. ** Additionally, an instance of this structure can be used as an ** output variable when querying the system for the current mutex ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. ** ** ^The xMutexInit method defined by this structure is invoked as ** part of system initialization by the sqlite3_initialize() function. ** ^The xMutexInit routine is calle by SQLite exactly once for each ** effective call to [sqlite3_initialize()]. ** ** ^The xMutexEnd method defined by this structure is invoked as ** part of system shutdown by the sqlite3_shutdown() function. The ** implementation of this method is expected to release all outstanding ** resources obtained by the mutex methods implementation, especially ** those obtained by the xMutexInit method. ^The xMutexEnd() ** interface is invoked exactly once for each call to [sqlite3_shutdown()]. ** ** ^(The remaining seven methods defined by this structure (xMutexAlloc, ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and ** xMutexNotheld) implement the following interfaces (respectively): ** ** )^ ** ** The only difference is that the public sqlite3_XXX functions enumerated ** above silently ignore any invocations that pass a NULL pointer instead ** of a valid mutex handle. The implementations of the methods defined ** by this structure are not required to handle this case, the results ** of passing a NULL pointer instead of a valid mutex handle are undefined ** (i.e. it is acceptable to provide an implementation that segfaults if ** it is passed a NULL pointer). ** ** The xMutexInit() method must be threadsafe. ^It must be harmless to ** invoke xMutexInit() mutiple times within the same process and without ** intervening calls to xMutexEnd(). Second and subsequent calls to ** xMutexInit() must be no-ops. ** ** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] ** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory ** allocation for a static mutex. ^However xMutexAlloc() may use SQLite ** memory allocation for a fast or recursive mutex. ** ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is ** called, but only if the prior call to xMutexInit returned SQLITE_OK. ** If xMutexInit fails in any way, it is expected to clean up after itself ** prior to returning. */ typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; struct sqlite3_mutex_methods { int (*xMutexInit)(void); int (*xMutexEnd)(void); sqlite3_mutex *(*xMutexAlloc)(int); void (*xMutexFree)(sqlite3_mutex *); void (*xMutexEnter)(sqlite3_mutex *); int (*xMutexTry)(sqlite3_mutex *); void (*xMutexLeave)(sqlite3_mutex *); int (*xMutexHeld)(sqlite3_mutex *); int (*xMutexNotheld)(sqlite3_mutex *); }; /* ** CAPI3REF: Mutex Verification Routines ** ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines ** are intended for use inside assert() statements. ^The SQLite core ** never uses these routines except inside an assert() and applications ** are advised to follow the lead of the core. ^The SQLite core only ** provides implementations for these routines when it is compiled ** with the SQLITE_DEBUG flag. ^External mutex implementations ** are only required to provide these routines if SQLITE_DEBUG is ** defined and if NDEBUG is not defined. ** ** ^These routines should return true if the mutex in their argument ** is held or not held, respectively, by the calling thread. ** ** ^The implementation is not required to provided versions of these ** routines that actually work. If the implementation does not provide working ** versions of these routines, it should at least provide stubs that always ** return true so that one does not get spurious assertion failures. ** ** ^If the argument to sqlite3_mutex_held() is a NULL pointer then ** the routine should return 1. This seems counter-intuitive since ** clearly the mutex cannot be held if it does not exist. But the ** the reason the mutex does not exist is because the build is not ** using mutexes. And we do not want the assert() containing the ** call to sqlite3_mutex_held() to fail, so a non-zero return is ** the appropriate thing to do. ^The sqlite3_mutex_notheld() ** interface should also return 1 when given a NULL pointer. */ #ifndef NDEBUG SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*); SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*); #endif /* ** CAPI3REF: Mutex Types ** ** The [sqlite3_mutex_alloc()] interface takes a single argument ** which is one of these integer constants. ** ** The set of static mutexes may change from one SQLite release to the ** next. Applications that override the built-in mutex logic must be ** prepared to accommodate additional static mutexes. */ #define SQLITE_MUTEX_FAST 0 #define SQLITE_MUTEX_RECURSIVE 1 #define SQLITE_MUTEX_STATIC_MASTER 2 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ #define SQLITE_MUTEX_STATIC_LRU2 7 /* lru page list */ /* ** CAPI3REF: Retrieve the mutex for a database connection ** ** ^This interface returns a pointer the [sqlite3_mutex] object that ** serializes access to the [database connection] given in the argument ** when the [threading mode] is Serialized. ** ^If the [threading mode] is Single-thread or Multi-thread then this ** routine returns a NULL pointer. */ SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*); /* ** CAPI3REF: Low-Level Control Of Database Files ** ** ^The [sqlite3_file_control()] interface makes a direct call to the ** xFileControl method for the [sqlite3_io_methods] object associated ** with a particular database identified by the second argument. ^The ** name of the database "main" for the main database or "temp" for the ** TEMP database, or the name that appears after the AS keyword for ** databases that are added using the [ATTACH] SQL command. ** ^A NULL pointer can be used in place of "main" to refer to the ** main database file. ** ^The third and fourth parameters to this routine ** are passed directly through to the second and third parameters of ** the xFileControl method. ^The return value of the xFileControl ** method becomes the return value of this routine. ** ** ^If the second parameter (zDbName) does not match the name of any ** open database file, then SQLITE_ERROR is returned. ^This error ** code is not remembered and will not be recalled by [sqlite3_errcode()] ** or [sqlite3_errmsg()]. The underlying xFileControl method might ** also return SQLITE_ERROR. There is no way to distinguish between ** an incorrect zDbName and an SQLITE_ERROR return from the underlying ** xFileControl method. ** ** See also: [SQLITE_FCNTL_LOCKSTATE] */ SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); /* ** CAPI3REF: Testing Interface ** ** ^The sqlite3_test_control() interface is used to read out internal ** state of SQLite and to inject faults into SQLite for testing ** purposes. ^The first parameter is an operation code that determines ** the number, meaning, and operation of all subsequent parameters. ** ** This interface is not for use by applications. It exists solely ** for verifying the correct operation of the SQLite library. Depending ** on how the SQLite library is compiled, this interface might not exist. ** ** The details of the operation codes, their meanings, the parameters ** they take, and what they do are all subject to change without notice. ** Unlike most of the SQLite API, this function is not guaranteed to ** operate consistently from one release to the next. */ SQLITE_API int sqlite3_test_control(int op, ...); /* ** CAPI3REF: Testing Interface Operation Codes ** ** These constants are the valid operation code parameters used ** as the first argument to [sqlite3_test_control()]. ** ** These parameters and their meanings are subject to change ** without notice. These values are for testing purposes only. ** Applications should not use any of these parameters or the ** [sqlite3_test_control()] interface. */ #define SQLITE_TESTCTRL_FIRST 5 #define SQLITE_TESTCTRL_PRNG_SAVE 5 #define SQLITE_TESTCTRL_PRNG_RESTORE 6 #define SQLITE_TESTCTRL_PRNG_RESET 7 #define SQLITE_TESTCTRL_BITVEC_TEST 8 #define SQLITE_TESTCTRL_FAULT_INSTALL 9 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 #define SQLITE_TESTCTRL_PENDING_BYTE 11 #define SQLITE_TESTCTRL_ASSERT 12 #define SQLITE_TESTCTRL_ALWAYS 13 #define SQLITE_TESTCTRL_RESERVE 14 #define SQLITE_TESTCTRL_OPTIMIZATIONS 15 #define SQLITE_TESTCTRL_ISKEYWORD 16 #define SQLITE_TESTCTRL_PGHDRSZ 17 #define SQLITE_TESTCTRL_LAST 17 /* ** CAPI3REF: SQLite Runtime Status ** ** ^This interface is used to retrieve runtime status information ** about the preformance of SQLite, and optionally to reset various ** highwater marks. ^The first argument is an integer code for ** the specific parameter to measure. ^(Recognized integer codes ** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].)^ ** ^The current value of the parameter is returned into *pCurrent. ** ^The highest recorded value is returned in *pHighwater. ^If the ** resetFlag is true, then the highest record value is reset after ** *pHighwater is written. ^(Some parameters do not record the highest ** value. For those parameters ** nothing is written into *pHighwater and the resetFlag is ignored.)^ ** ^(Other parameters record only the highwater mark and not the current ** value. For these latter parameters nothing is written into *pCurrent.)^ ** ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a ** non-zero [error code] on failure. ** ** This routine is threadsafe but is not atomic. This routine can be ** called while other threads are running the same or different SQLite ** interfaces. However the values returned in *pCurrent and ** *pHighwater reflect the status of SQLite at different points in time ** and it is possible that another thread might change the parameter ** in between the times when *pCurrent and *pHighwater are written. ** ** See also: [sqlite3_db_status()] */ SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); /* ** CAPI3REF: Status Parameters ** ** These integer constants designate various run-time status parameters ** that can be returned by [sqlite3_status()]. ** **
** ^(
SQLITE_STATUS_MEMORY_USED
**
This parameter is the current amount of memory checked out ** using [sqlite3_malloc()], either directly or indirectly. The ** figure includes calls made to [sqlite3_malloc()] by the application ** and internal memory usage by the SQLite library. Scratch memory ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in ** this parameter. The amount returned is the sum of the allocation ** sizes as reported by the xSize method in [sqlite3_mem_methods].
)^ ** ** ^(
SQLITE_STATUS_MALLOC_SIZE
**
This parameter records the largest memory allocation request ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their ** internal equivalents). Only the value returned in the ** *pHighwater parameter to [sqlite3_status()] is of interest. ** The value written into the *pCurrent parameter is undefined.
)^ ** ** ^(
SQLITE_STATUS_PAGECACHE_USED
**
This parameter returns the number of pages used out of the ** [pagecache memory allocator] that was configured using ** [SQLITE_CONFIG_PAGECACHE]. The ** value returned is in pages, not in bytes.
)^ ** ** ^(
SQLITE_STATUS_PAGECACHE_OVERFLOW
**
This parameter returns the number of bytes of page cache ** allocation which could not be statisfied by the [SQLITE_CONFIG_PAGECACHE] ** buffer and where forced to overflow to [sqlite3_malloc()]. The ** returned value includes allocations that overflowed because they ** where too large (they were larger than the "sz" parameter to ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because ** no space was left in the page cache.
)^ ** ** ^(
SQLITE_STATUS_PAGECACHE_SIZE
**
This parameter records the largest memory allocation request ** handed to [pagecache memory allocator]. Only the value returned in the ** *pHighwater parameter to [sqlite3_status()] is of interest. ** The value written into the *pCurrent parameter is undefined.
)^ ** ** ^(
SQLITE_STATUS_SCRATCH_USED
**
This parameter returns the number of allocations used out of the ** [scratch memory allocator] configured using ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not ** in bytes. Since a single thread may only have one scratch allocation ** outstanding at time, this parameter also reports the number of threads ** using scratch memory at the same time.
)^ ** ** ^(
SQLITE_STATUS_SCRATCH_OVERFLOW
**
This parameter returns the number of bytes of scratch memory ** allocation which could not be statisfied by the [SQLITE_CONFIG_SCRATCH] ** buffer and where forced to overflow to [sqlite3_malloc()]. The values ** returned include overflows because the requested allocation was too ** larger (that is, because the requested allocation was larger than the ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer ** slots were available. **
)^ ** ** ^(
SQLITE_STATUS_SCRATCH_SIZE
**
This parameter records the largest memory allocation request ** handed to [scratch memory allocator]. Only the value returned in the ** *pHighwater parameter to [sqlite3_status()] is of interest. ** The value written into the *pCurrent parameter is undefined.
)^ ** ** ^(
SQLITE_STATUS_PARSER_STACK
**
This parameter records the deepest parser stack. It is only ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].
)^ **
** ** New status parameters may be added from time to time. */ #define SQLITE_STATUS_MEMORY_USED 0 #define SQLITE_STATUS_PAGECACHE_USED 1 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 #define SQLITE_STATUS_SCRATCH_USED 3 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4 #define SQLITE_STATUS_MALLOC_SIZE 5 #define SQLITE_STATUS_PARSER_STACK 6 #define SQLITE_STATUS_PAGECACHE_SIZE 7 #define SQLITE_STATUS_SCRATCH_SIZE 8 /* ** CAPI3REF: Database Connection Status ** ** ^This interface is used to retrieve runtime status information ** about a single [database connection]. ^The first argument is the ** database connection object to be interrogated. ^The second argument ** is an integer constant, taken from the set of ** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros, that ** determiness the parameter to interrogate. The set of ** [SQLITE_DBSTATUS_LOOKASIDE_USED | SQLITE_DBSTATUS_*] macros is likely ** to grow in future releases of SQLite. ** ** ^The current value of the requested parameter is written into *pCur ** and the highest instantaneous value is written into *pHiwtr. ^If ** the resetFlg is true, then the highest instantaneous value is ** reset back down to the current value. ** ** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. */ SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); /* ** CAPI3REF: Status Parameters for database connections ** ** These constants are the available integer "verbs" that can be passed as ** the second argument to the [sqlite3_db_status()] interface. ** ** New verbs may be added in future releases of SQLite. Existing verbs ** might be discontinued. Applications should check the return code from ** [sqlite3_db_status()] to make sure that the call worked. ** The [sqlite3_db_status()] interface will return a non-zero error code ** if a discontinued or unsupported verb is invoked. ** **
** ^(
SQLITE_DBSTATUS_LOOKASIDE_USED
**
This parameter returns the number of lookaside memory slots currently ** checked out.
)^ ** **
SQLITE_DBSTATUS_CACHE_USED
**
^This parameter returns the approximate number of of bytes of heap ** memory used by all pager caches associated with the database connection. ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. **
**
*/ #define SQLITE_DBSTATUS_LOOKASIDE_USED 0 #define SQLITE_DBSTATUS_CACHE_USED 1 #define SQLITE_DBSTATUS_MAX 1 /* Largest defined DBSTATUS */ /* ** CAPI3REF: Prepared Statement Status ** ** ^(Each prepared statement maintains various ** [SQLITE_STMTSTATUS_SORT | counters] that measure the number ** of times it has performed specific operations.)^ These counters can ** be used to monitor the performance characteristics of the prepared ** statements. For example, if the number of table steps greatly exceeds ** the number of table searches or result rows, that would tend to indicate ** that the prepared statement is using a full table scan rather than ** an index. ** ** ^(This interface is used to retrieve and reset counter values from ** a [prepared statement]. The first argument is the prepared statement ** object to be interrogated. The second argument ** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter] ** to be interrogated.)^ ** ^The current value of the requested counter is returned. ** ^If the resetFlg is true, then the counter is reset to zero after this ** interface call returns. ** ** See also: [sqlite3_status()] and [sqlite3_db_status()]. */ SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); /* ** CAPI3REF: Status Parameters for prepared statements ** ** These preprocessor macros define integer codes that name counter ** values associated with the [sqlite3_stmt_status()] interface. ** The meanings of the various counters are as follows: ** **
**
SQLITE_STMTSTATUS_FULLSCAN_STEP
**
^This is the number of times that SQLite has stepped forward in ** a table as part of a full table scan. Large numbers for this counter ** may indicate opportunities for performance improvement through ** careful use of indices.
** **
SQLITE_STMTSTATUS_SORT
**
^This is the number of sort operations that have occurred. ** A non-zero value in this counter may indicate an opportunity to ** improvement performance through careful use of indices.
** **
SQLITE_STMTSTATUS_AUTOINDEX
**
^This is the number of rows inserted into transient indices that ** were created automatically in order to help joins run faster. ** A non-zero value in this counter may indicate an opportunity to ** improvement performance by adding permanent indices that do not ** need to be reinitialized each time the statement is run.
** **
*/ #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 #define SQLITE_STMTSTATUS_SORT 2 #define SQLITE_STMTSTATUS_AUTOINDEX 3 /* ** CAPI3REF: Custom Page Cache Object ** ** The sqlite3_pcache type is opaque. It is implemented by ** the pluggable module. The SQLite core has no knowledge of ** its size or internal structure and never deals with the ** sqlite3_pcache object except by holding and passing pointers ** to the object. ** ** See [sqlite3_pcache_methods] for additional information. */ typedef struct sqlite3_pcache sqlite3_pcache; /* ** CAPI3REF: Application Defined Page Cache. ** KEYWORDS: {page cache} ** ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can ** register an alternative page cache implementation by passing in an ** instance of the sqlite3_pcache_methods structure.)^ The majority of the ** heap memory used by SQLite is used by the page cache to cache data read ** from, or ready to be written to, the database file. By implementing a ** custom page cache using this API, an application can control more ** precisely the amount of memory consumed by SQLite, the way in which ** that memory is allocated and released, and the policies used to ** determine exactly which parts of a database file are cached and for ** how long. ** ** ^(The contents of the sqlite3_pcache_methods structure are copied to an ** internal buffer by SQLite within the call to [sqlite3_config]. Hence ** the application may discard the parameter after the call to ** [sqlite3_config()] returns.)^ ** ** ^The xInit() method is called once for each call to [sqlite3_initialize()] ** (usually only once during the lifetime of the process). ^(The xInit() ** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^ ** ^The xInit() method can set up up global structures and/or any mutexes ** required by the custom page cache implementation. ** ** ^The xShutdown() method is called from within [sqlite3_shutdown()], ** if the application invokes this API. It can be used to clean up ** any outstanding resources before process shutdown, if required. ** ** ^SQLite holds a [SQLITE_MUTEX_RECURSIVE] mutex when it invokes ** the xInit method, so the xInit method need not be threadsafe. ^The ** xShutdown method is only called from [sqlite3_shutdown()] so it does ** not need to be threadsafe either. All other methods must be threadsafe ** in multithreaded applications. ** ** ^SQLite will never invoke xInit() more than once without an intervening ** call to xShutdown(). ** ** ^The xCreate() method is used to construct a new cache instance. SQLite ** will typically create one cache instance for each open database file, ** though this is not guaranteed. ^The ** first parameter, szPage, is the size in bytes of the pages that must ** be allocated by the cache. ^szPage will not be a power of two. ^szPage ** will the page size of the database file that is to be cached plus an ** increment (here called "R") of about 100 or 200. ^SQLite will use the ** extra R bytes on each page to store metadata about the underlying ** database page on disk. The value of R depends ** on the SQLite version, the target platform, and how SQLite was compiled. ** ^R is constant for a particular build of SQLite. ^The second argument to ** xCreate(), bPurgeable, is true if the cache being created will ** be used to cache database pages of a file stored on disk, or ** false if it is used for an in-memory database. ^The cache implementation ** does not have to do anything special based with the value of bPurgeable; ** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will ** never invoke xUnpin() except to deliberately delete a page. ** ^In other words, a cache created with bPurgeable set to false will ** never contain any unpinned pages. ** ** ^(The xCachesize() method may be called at any time by SQLite to set the ** suggested maximum cache-size (number of pages stored by) the cache ** instance passed as the first argument. This is the value configured using ** the SQLite "[PRAGMA cache_size]" command.)^ ^As with the bPurgeable ** parameter, the implementation is not required to do anything with this ** value; it is advisory only. ** ** ^The xPagecount() method should return the number of pages currently ** stored in the cache. ** ** ^The xFetch() method is used to fetch a page and return a pointer to it. ** ^A 'page', in this context, is a buffer of szPage bytes aligned at an ** 8-byte boundary. ^The page to be fetched is determined by the key. ^The ** mimimum key value is 1. After it has been retrieved using xFetch, the page ** is considered to be "pinned". ** ** ^If the requested page is already in the page cache, then the page cache ** implementation must return a pointer to the page buffer with its content ** intact. ^(If the requested page is not already in the cache, then the ** behavior of the cache implementation is determined by the value of the ** createFlag parameter passed to xFetch, according to the following table: ** ** **
createFlag Behaviour when page is not already in cache **
0 Do not allocate a new page. Return NULL. **
1 Allocate a new page if it easy and convenient to do so. ** Otherwise return NULL. **
2 Make every effort to allocate a new page. Only return ** NULL if allocating a new page is effectively impossible. **
)^ ** ** SQLite will normally invoke xFetch() with a createFlag of 0 or 1. If ** a call to xFetch() with createFlag==1 returns NULL, then SQLite will ** attempt to unpin one or more cache pages by spilling the content of ** pinned pages to disk and synching the operating system disk cache. After ** attempting to unpin pages, the xFetch() method will be invoked again with ** a createFlag of 2. ** ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page ** as its second argument. ^(If the third parameter, discard, is non-zero, ** then the page should be evicted from the cache. In this case SQLite ** assumes that the next time the page is retrieved from the cache using ** the xFetch() method, it will be zeroed.)^ ^If the discard parameter is ** zero, then the page is considered to be unpinned. ^The cache implementation ** may choose to evict unpinned pages at any time. ** ** ^(The cache is not required to perform any reference counting. A single ** call to xUnpin() unpins the page regardless of the number of prior calls ** to xFetch().)^ ** ** ^The xRekey() method is used to change the key value associated with the ** page passed as the second argument from oldKey to newKey. ^If the cache ** previously contains an entry associated with newKey, it should be ** discarded. ^Any prior cache entry associated with newKey is guaranteed not ** to be pinned. ** ** ^When SQLite calls the xTruncate() method, the cache must discard all ** existing cache entries with page numbers (keys) greater than or equal ** to the value of the iLimit parameter passed to xTruncate(). ^If any ** of these pages are pinned, they are implicitly unpinned, meaning that ** they can be safely discarded. ** ** ^The xDestroy() method is used to delete a cache allocated by xCreate(). ** All resources associated with the specified cache should be freed. ^After ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] ** handle invalid, and will not use it with any other sqlite3_pcache_methods ** functions. */ typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; struct sqlite3_pcache_methods { void *pArg; int (*xInit)(void*); void (*xShutdown)(void*); sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); void (*xCachesize)(sqlite3_pcache*, int nCachesize); int (*xPagecount)(sqlite3_pcache*); void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); void (*xUnpin)(sqlite3_pcache*, void*, int discard); void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); void (*xDestroy)(sqlite3_pcache*); }; /* ** CAPI3REF: Online Backup Object ** ** The sqlite3_backup object records state information about an ongoing ** online backup operation. ^The sqlite3_backup object is created by ** a call to [sqlite3_backup_init()] and is destroyed by a call to ** [sqlite3_backup_finish()]. ** ** See Also: [Using the SQLite Online Backup API] */ typedef struct sqlite3_backup sqlite3_backup; /* ** CAPI3REF: Online Backup API. ** ** The backup API copies the content of one database into another. ** It is useful either for creating backups of databases or ** for copying in-memory databases to or from persistent files. ** ** See Also: [Using the SQLite Online Backup API] ** ** ^Exclusive access is required to the destination database for the ** duration of the operation. ^However the source database is only ** read-locked while it is actually being read; it is not locked ** continuously for the entire backup operation. ^Thus, the backup may be ** performed on a live source database without preventing other users from ** reading or writing to the source database while the backup is underway. ** ** ^(To perform a backup operation: **
    **
  1. sqlite3_backup_init() is called once to initialize the ** backup, **
  2. sqlite3_backup_step() is called one or more times to transfer ** the data between the two databases, and finally **
  3. sqlite3_backup_finish() is called to release all resources ** associated with the backup operation. **
)^ ** There should be exactly one call to sqlite3_backup_finish() for each ** successful call to sqlite3_backup_init(). ** ** sqlite3_backup_init() ** ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the ** [database connection] associated with the destination database ** and the database name, respectively. ** ^The database name is "main" for the main database, "temp" for the ** temporary database, or the name specified after the AS keyword in ** an [ATTACH] statement for an attached database. ** ^The S and M arguments passed to ** sqlite3_backup_init(D,N,S,M) identify the [database connection] ** and database name of the source database, respectively. ** ^The source and destination [database connections] (parameters S and D) ** must be different or else sqlite3_backup_init(D,N,S,M) will file with ** an error. ** ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is ** returned and an error code and error message are store3d in the ** destination [database connection] D. ** ^The error code and message for the failed call to sqlite3_backup_init() ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or ** [sqlite3_errmsg16()] functions. ** ^A successful call to sqlite3_backup_init() returns a pointer to an ** [sqlite3_backup] object. ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and ** sqlite3_backup_finish() functions to perform the specified backup ** operation. ** ** sqlite3_backup_step() ** ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between ** the source and destination databases specified by [sqlite3_backup] object B. ** ^If N is negative, all remaining source pages are copied. ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there ** are still more pages to be copied, then the function resturns [SQLITE_OK]. ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages ** from source to destination, then it returns [SQLITE_DONE]. ** ^If an error occurs while running sqlite3_backup_step(B,N), ** then an [error code] is returned. ^As well as [SQLITE_OK] and ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. ** ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if **
    **
  1. the destination database was opened read-only, or **
  2. the destination database is using write-ahead-log journaling ** and the destination and source page sizes differ, or **
  3. The destination database is an in-memory database and the ** destination and source page sizes differ. **
)^ ** ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then ** the [sqlite3_busy_handler | busy-handler function] ** is invoked (if one is specified). ^If the ** busy-handler returns non-zero before the lock is available, then ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to ** sqlite3_backup_step() can be retried later. ^If the source ** [database connection] ** is being used to write to the source database when sqlite3_backup_step() ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this ** case the call to sqlite3_backup_step() can be retried later on. ^(If ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or ** [SQLITE_READONLY] is returned, then ** there is no point in retrying the call to sqlite3_backup_step(). These ** errors are considered fatal.)^ The application must accept ** that the backup operation has failed and pass the backup operation handle ** to the sqlite3_backup_finish() to release associated resources. ** ** ^The first call to sqlite3_backup_step() obtains an exclusive lock ** on the destination file. ^The exclusive lock is not released until either ** sqlite3_backup_finish() is called or the backup operation is complete ** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to ** sqlite3_backup_step() obtains a [shared lock] on the source database that ** lasts for the duration of the sqlite3_backup_step() call. ** ^Because the source database is not locked between calls to ** sqlite3_backup_step(), the source database may be modified mid-way ** through the backup process. ^If the source database is modified by an ** external process or via a database connection other than the one being ** used by the backup operation, then the backup will be automatically ** restarted by the next call to sqlite3_backup_step(). ^If the source ** database is modified by the using the same database connection as is used ** by the backup operation, then the backup database is automatically ** updated at the same time. ** ** sqlite3_backup_finish() ** ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the ** application wishes to abandon the backup operation, the application ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). ** ^The sqlite3_backup_finish() interfaces releases all ** resources associated with the [sqlite3_backup] object. ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any ** active write-transaction on the destination database is rolled back. ** The [sqlite3_backup] object is invalid ** and may not be used following a call to sqlite3_backup_finish(). ** ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no ** sqlite3_backup_step() errors occurred, regardless or whether or not ** sqlite3_backup_step() completed. ** ^If an out-of-memory condition or IO error occurred during any prior ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then ** sqlite3_backup_finish() returns the corresponding [error code]. ** ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() ** is not a permanent error and does not affect the return value of ** sqlite3_backup_finish(). ** ** sqlite3_backup_remaining(), sqlite3_backup_pagecount() ** ** ^Each call to sqlite3_backup_step() sets two values inside ** the [sqlite3_backup] object: the number of pages still to be backed ** up and the total number of pages in the source databae file. ** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces ** retrieve these two values, respectively. ** ** ^The values returned by these functions are only updated by ** sqlite3_backup_step(). ^If the source database is modified during a backup ** operation, then the values are not updated to account for any extra ** pages that need to be updated or the size of the source database file ** changing. ** ** Concurrent Usage of Database Handles ** ** ^The source [database connection] may be used by the application for other ** purposes while a backup operation is underway or being initialized. ** ^If SQLite is compiled and configured to support threadsafe database ** connections, then the source database connection may be used concurrently ** from within other threads. ** ** However, the application must guarantee that the destination ** [database connection] is not passed to any other API (by any thread) after ** sqlite3_backup_init() is called and before the corresponding call to ** sqlite3_backup_finish(). SQLite does not currently check to see ** if the application incorrectly accesses the destination [database connection] ** and so no error code is reported, but the operations may malfunction ** nevertheless. Use of the destination database connection while a ** backup is in progress might also also cause a mutex deadlock. ** ** If running in [shared cache mode], the application must ** guarantee that the shared cache used by the destination database ** is not accessed while the backup is running. In practice this means ** that the application must guarantee that the disk file being ** backed up to is not accessed by any connection within the process, ** not just the specific connection that was passed to sqlite3_backup_init(). ** ** The [sqlite3_backup] object itself is partially threadsafe. Multiple ** threads may safely make multiple concurrent calls to sqlite3_backup_step(). ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() ** APIs are not strictly speaking threadsafe. If they are invoked at the ** same time as another thread is invoking sqlite3_backup_step() it is ** possible that they return invalid values. */ SQLITE_API sqlite3_backup *sqlite3_backup_init( sqlite3 *pDest, /* Destination database handle */ const char *zDestName, /* Destination database name */ sqlite3 *pSource, /* Source database handle */ const char *zSourceName /* Source database name */ ); SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage); SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p); SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p); SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p); /* ** CAPI3REF: Unlock Notification ** ** ^When running in shared-cache mode, a database operation may fail with ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or ** individual tables within the shared-cache cannot be obtained. See ** [SQLite Shared-Cache Mode] for a description of shared-cache locking. ** ^This API may be used to register a callback that SQLite will invoke ** when the connection currently holding the required lock relinquishes it. ** ^This API is only available if the library was compiled with the ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. ** ** See Also: [Using the SQLite Unlock Notification Feature]. ** ** ^Shared-cache locks are released when a database connection concludes ** its current transaction, either by committing it or rolling it back. ** ** ^When a connection (known as the blocked connection) fails to obtain a ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the ** identity of the database connection (the blocking connection) that ** has locked the required resource is stored internally. ^After an ** application receives an SQLITE_LOCKED error, it may call the ** sqlite3_unlock_notify() method with the blocked connection handle as ** the first argument to register for a callback that will be invoked ** when the blocking connections current transaction is concluded. ^The ** callback is invoked from within the [sqlite3_step] or [sqlite3_close] ** call that concludes the blocking connections transaction. ** ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, ** there is a chance that the blocking connection will have already ** concluded its transaction by the time sqlite3_unlock_notify() is invoked. ** If this happens, then the specified callback is invoked immediately, ** from within the call to sqlite3_unlock_notify().)^ ** ** ^If the blocked connection is attempting to obtain a write-lock on a ** shared-cache table, and more than one other connection currently holds ** a read-lock on the same table, then SQLite arbitrarily selects one of ** the other connections to use as the blocking connection. ** ** ^(There may be at most one unlock-notify callback registered by a ** blocked connection. If sqlite3_unlock_notify() is called when the ** blocked connection already has a registered unlock-notify callback, ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is ** called with a NULL pointer as its second argument, then any existing ** unlock-notify callback is cancelled. ^The blocked connections ** unlock-notify callback may also be canceled by closing the blocked ** connection using [sqlite3_close()]. ** ** The unlock-notify callback is not reentrant. If an application invokes ** any sqlite3_xxx API functions from within an unlock-notify callback, a ** crash or deadlock may be the result. ** ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always ** returns SQLITE_OK. ** ** Callback Invocation Details ** ** When an unlock-notify callback is registered, the application provides a ** single void* pointer that is passed to the callback when it is invoked. ** However, the signature of the callback function allows SQLite to pass ** it an array of void* context pointers. The first argument passed to ** an unlock-notify callback is a pointer to an array of void* pointers, ** and the second is the number of entries in the array. ** ** When a blocking connections transaction is concluded, there may be ** more than one blocked connection that has registered for an unlock-notify ** callback. ^If two or more such blocked connections have specified the ** same callback function, then instead of invoking the callback function ** multiple times, it is invoked once with the set of void* context pointers ** specified by the blocked connections bundled together into an array. ** This gives the application an opportunity to prioritize any actions ** related to the set of unblocked database connections. ** ** Deadlock Detection ** ** Assuming that after registering for an unlock-notify callback a ** database waits for the callback to be issued before taking any further ** action (a reasonable assumption), then using this API may cause the ** application to deadlock. For example, if connection X is waiting for ** connection Y's transaction to be concluded, and similarly connection ** Y is waiting on connection X's transaction, then neither connection ** will proceed and the system may remain deadlocked indefinitely. ** ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock ** detection. ^If a given call to sqlite3_unlock_notify() would put the ** system in a deadlocked state, then SQLITE_LOCKED is returned and no ** unlock-notify callback is registered. The system is said to be in ** a deadlocked state if connection A has registered for an unlock-notify ** callback on the conclusion of connection B's transaction, and connection ** B has itself registered for an unlock-notify callback when connection ** A's transaction is concluded. ^Indirect deadlock is also detected, so ** the system is also considered to be deadlocked if connection B has ** registered for an unlock-notify callback on the conclusion of connection ** C's transaction, where connection C is waiting on connection A. ^Any ** number of levels of indirection are allowed. ** ** The "DROP TABLE" Exception ** ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost ** always appropriate to call sqlite3_unlock_notify(). There is however, ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, ** SQLite checks if there are any currently executing SELECT statements ** that belong to the same connection. If there are, SQLITE_LOCKED is ** returned. In this case there is no "blocking connection", so invoking ** sqlite3_unlock_notify() results in the unlock-notify callback being ** invoked immediately. If the application then re-attempts the "DROP TABLE" ** or "DROP INDEX" query, an infinite loop might be the result. ** ** One way around this problem is to check the extended error code returned ** by an sqlite3_step() call. ^(If there is a blocking connection, then the ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in ** the special "DROP TABLE/INDEX" case, the extended error code is just ** SQLITE_LOCKED.)^ */ SQLITE_API int sqlite3_unlock_notify( sqlite3 *pBlocked, /* Waiting connection */ void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ void *pNotifyArg /* Argument to pass to xNotify */ ); /* ** CAPI3REF: String Comparison ** ** ^The [sqlite3_strnicmp()] API allows applications and extensions to ** compare the contents of two buffers containing UTF-8 strings in a ** case-indendent fashion, using the same definition of case independence ** that SQLite uses internally when comparing identifiers. */ SQLITE_API int sqlite3_strnicmp(const char *, const char *, int); /* ** CAPI3REF: Error Logging Interface ** ** ^The [sqlite3_log()] interface writes a message into the error log ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. ** ^If logging is enabled, the zFormat string and subsequent arguments are ** used with [sqlite3_snprintf()] to generate the final output string. ** ** The sqlite3_log() interface is intended for use by extensions such as ** virtual tables, collating functions, and SQL functions. While there is ** nothing to prevent an application from calling sqlite3_log(), doing so ** is considered bad form. ** ** The zFormat string must not be NULL. ** ** To avoid deadlocks and other threading problems, the sqlite3_log() routine ** will not use dynamically allocated memory. The log message is stored in ** a fixed-length buffer on the stack. If the log message is longer than ** a few hundred characters, it will be truncated to the length of the ** buffer. */ SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...); /* ** CAPI3REF: Write-Ahead Log Commit Hook ** ** ^The [sqlite3_wal_hook()] function is used to register a callback that ** will be invoked each time a database connection commits data to a ** [write-ahead log] (i.e. whenever a transaction is committed in ** [journal_mode | journal_mode=WAL mode]). ** ** ^The callback is invoked by SQLite after the commit has taken place and ** the associated write-lock on the database released, so the implementation ** may read, write or [checkpoint] the database as required. ** ** ^The first parameter passed to the callback function when it is invoked ** is a copy of the third parameter passed to sqlite3_wal_hook() when ** registering the callback. ^The second is a copy of the database handle. ** ^The third parameter is the name of the database that was written to - ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter ** is the number of pages currently in the write-ahead log file, ** including those that were just committed. ** ** The callback function should normally return [SQLITE_OK]. ^If an error ** code is returned, that error will propagate back up through the ** SQLite code base to cause the statement that provoked the callback ** to report an error, though the commit will have still occurred. If the ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value ** that does not correspond to any valid SQLite error code, the results ** are undefined. ** ** A single database handle may have at most a single write-ahead log callback ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any ** previously registered write-ahead log callback. ^Note that the ** [sqlite3_wal_autocheckpoint()] interface and the ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will ** those overwrite any prior [sqlite3_wal_hook()] settings. */ SQLITE_API void *sqlite3_wal_hook( sqlite3*, int(*)(void *,sqlite3*,const char*,int), void* ); /* ** CAPI3REF: Configure an auto-checkpoint ** ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around ** [sqlite3_wal_hook()] that causes any database on [database connection] D ** to automatically [checkpoint] ** after committing a transaction if there are N or ** more frames in the [write-ahead log] file. ^Passing zero or ** a negative value as the nFrame parameter disables automatic ** checkpoints entirely. ** ** ^The callback registered by this function replaces any existing callback ** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism ** configured by this function. ** ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface ** from SQL. ** ** ^Every new [database connection] defaults to having the auto-checkpoint ** enabled with a threshold of 1000 pages. The use of this interface ** is only necessary if the default setting is found to be suboptimal ** for a particular application. */ SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); /* ** CAPI3REF: Checkpoint a database ** ** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X ** on [database connection] D to be [checkpointed]. ^If X is NULL or an ** empty string, then a checkpoint is run on all databases of ** connection D. ^If the database connection D is not in ** [WAL | write-ahead log mode] then this interface is a harmless no-op. ** ** ^The [wal_checkpoint pragma] can be used to invoke this interface ** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the ** [wal_autocheckpoint pragma] can be used to cause this interface to be ** run whenever the WAL reaches a certain size threshold. */ SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); /* ** Undo the hack that converts floating point types to integer for ** builds on processors without floating point support. */ #ifdef SQLITE_OMIT_FLOATING_POINT # undef double #endif #ifdef __cplusplus } /* End of the 'extern "C"' block */ #endif #endif