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5957 lines (5799 loc) · 274 KB
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/*
** 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 <stdarg.h> /* 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
/*
** 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
** <a href="http://www.fossil-scm.org/">Fossil configuration management
** system</a>. ^The SQLITE_SOURCE_ID macro evaluates 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 "--VERS--"
#define SQLITE_VERSION_NUMBER --VERSION-NUMBER--
#define SQLITE_SOURCE_ID "--SOURCE-ID--"
/*
** 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.
**
** <blockquote><pre>
** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 );
** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
** </pre></blockquote>)^
**
** ^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_EXTERN const char sqlite3_version[];
const char *sqlite3_libversion(void);
const char *sqlite3_sourceid(void);
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 iterating
** 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 specifying 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
int sqlite3_compileoption_used(const char *zOptName);
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.
*/
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
** successfully 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.
*/
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:
**
** <ul>
** <li> The application must insure that the 1st parameter to sqlite3_exec()
** is a valid and open [database connection].
** <li> The application must not close [database connection] specified by
** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
** <li> The application must not modify the SQL statement text passed into
** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
** </ul>
*/
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
** <ul>
** <li> [SQLITE_LOCK_NONE],
** <li> [SQLITE_LOCK_SHARED],
** <li> [SQLITE_LOCK_RESERVED],
** <li> [SQLITE_LOCK_PENDING], or
** <li> [SQLITE_LOCK_EXCLUSIVE].
** </ul>
** 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:
**
** <ul>
** <li> [SQLITE_IOCAP_ATOMIC]
** <li> [SQLITE_IOCAP_ATOMIC512]
** <li> [SQLITE_IOCAP_ATOMIC1K]
** <li> [SQLITE_IOCAP_ATOMIC2K]
** <li> [SQLITE_IOCAP_ATOMIC4K]
** <li> [SQLITE_IOCAP_ATOMIC8K]
** <li> [SQLITE_IOCAP_ATOMIC16K]
** <li> [SQLITE_IOCAP_ATOMIC32K]
** <li> [SQLITE_IOCAP_ATOMIC64K]
** <li> [SQLITE_IOCAP_SAFE_APPEND]
** <li> [SQLITE_IOCAP_SEQUENTIAL]
** </ul>
**
** 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.
**
** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
** extends and truncates the database file in chunks of a size specified
** by the user. The fourth argument to [sqlite3_file_control()] should
** point to an integer (type int) containing the new chunk-size to use
** for the nominated database. Allocating database file space in large
** chunks (say 1MB at a time), may reduce file-system fragmentation and
** improve performance on some systems.
*/
#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
#define SQLITE_FCNTL_CHUNK_SIZE 6
/*
** 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:
**
** <ul>
** <li> [SQLITE_OPEN_MAIN_DB]
** <li> [SQLITE_OPEN_MAIN_JOURNAL]
** <li> [SQLITE_OPEN_TEMP_DB]
** <li> [SQLITE_OPEN_TEMP_JOURNAL]
** <li> [SQLITE_OPEN_TRANSIENT_DB]
** <li> [SQLITE_OPEN_SUBJOURNAL]
** <li> [SQLITE_OPEN_MASTER_JOURNAL]
** </ul>
**
** 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:
**
** <ul>
** <li> [SQLITE_OPEN_DELETEONCLOSE]
** <li> [SQLITE_OPEN_EXCLUSIVE]
** </ul>
**
** 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 <i>not</i> 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:
**
** <ul>
** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
** </ul>
**
** 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