SQLite

** 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_EXPERIMENTAL int sqlite3_config(int, ...);

/*
** CAPI3REF: Configure database connections
** EXPERIMENTAL
**
** 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_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...);

/*
** CAPI3REF: Memory Allocation Routines
** EXPERIMENTAL
**
** 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

  int (*xInit)(void*);           /* Initialize the memory allocator */
  void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
  void *pAppData;                /* Argument to xInit() and xShutdown() */
};

/*
** CAPI3REF: Configuration Options
** EXPERIMENTAL
**
** 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

/* 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: Configuration Options
** EXPERIMENTAL
**
** 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

#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
** EXPERIMENTAL
**
** 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_EXPERIMENTAL void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
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

** [sqlite3_auto_extension()] calls.)^
**
** ^This function disables automatic extensions in all threads.
*/
void sqlite3_reset_auto_extension(void);

/*
****** EXPERIMENTAL - subject to change without notice **************
**
** 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}
** EXPERIMENTAL
**
** 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

                       void **ppArg);
  int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
};

/*
** CAPI3REF: Virtual Table Indexing Information
** KEYWORDS: sqlite3_index_info
** EXPERIMENTAL
**
** 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.
**

#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
** EXPERIMENTAL
**
** ^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

** ^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_EXPERIMENTAL 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_EXPERIMENTAL 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
** EXPERIMENTAL
**
** 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.

  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}
** EXPERIMENTAL
**
** 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

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
** EXPERIMENTAL
**
** ^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_EXPERIMENTAL int sqlite3_declare_vtab(sqlite3*, const char *zSQL);

/*
** CAPI3REF: Overload A Function For A Virtual Table
** EXPERIMENTAL
**
** ^(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_EXPERIMENTAL 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.
**
****** EXPERIMENTAL - subject to change without notice **************
*/

/*
** CAPI3REF: A Handle To An Open BLOB
** KEYWORDS: {BLOB handle} {BLOB handles}
**
** An instance of this object represents an open BLOB on which

void sqlite3_mutex_free(sqlite3_mutex*);
void sqlite3_mutex_enter(sqlite3_mutex*);
int sqlite3_mutex_try(sqlite3_mutex*);
void sqlite3_mutex_leave(sqlite3_mutex*);

/*
** CAPI3REF: Mutex Methods Object
** EXPERIMENTAL
**
** 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

#define SQLITE_TESTCTRL_RESERVE                 14
#define SQLITE_TESTCTRL_OPTIMIZATIONS           15
#define SQLITE_TESTCTRL_ISKEYWORD               16
#define SQLITE_TESTCTRL_LAST                    16

/*
** CAPI3REF: SQLite Runtime Status
** EXPERIMENTAL
**
** ^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.

** 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_EXPERIMENTAL int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);


/*
** CAPI3REF: Status Parameters
** EXPERIMENTAL
**
** These integer constants designate various run-time status parameters
** that can be returned by [sqlite3_status()].
**
** <dl>
** ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
** <dd>This parameter is the current amount of memory checked out

#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
** EXPERIMENTAL
**
** ^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 the parameter to interrogate.  ^Currently, the only allowed value
** for the second parameter is [SQLITE_DBSTATUS_LOOKASIDE_USED].
** Additional options will likely appear 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_EXPERIMENTAL int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);

/*
** CAPI3REF: Status Parameters for database connections
** EXPERIMENTAL
**
** 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.

** </dl>
*/
#define SQLITE_DBSTATUS_LOOKASIDE_USED     0


/*
** CAPI3REF: Prepared Statement Status
** EXPERIMENTAL
**
** ^(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

** 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_EXPERIMENTAL int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);

/*
** CAPI3REF: Status Parameters for prepared statements
** EXPERIMENTAL
**
** 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:
**
** <dl>
** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>

** </dl>
*/
#define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
#define SQLITE_STMTSTATUS_SORT              2

/*
** CAPI3REF: Custom Page Cache Object
** EXPERIMENTAL
**
** 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}
** EXPERIMENTAL
**
** ^(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 

  void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
  void (*xDestroy)(sqlite3_pcache*);
};

/*
** CAPI3REF: Online Backup Object
** EXPERIMENTAL
**
** 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.
** EXPERIMENTAL
**
** 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]
**

int sqlite3_backup_step(sqlite3_backup *p, int nPage);
int sqlite3_backup_finish(sqlite3_backup *p);
int sqlite3_backup_remaining(sqlite3_backup *p);
int sqlite3_backup_pagecount(sqlite3_backup *p);

/*
** CAPI3REF: Unlock Notification
** EXPERIMENTAL
**
** ^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.

  void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
  void *pNotifyArg                            /* Argument to pass to xNotify */
);


/*
** CAPI3REF: String Comparison
** EXPERIMENTAL
**
** ^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.
*/
int sqlite3_strnicmp(const char *, const char *, int);

/*
** CAPI3REF: Error Logging Interface
** EXPERIMENTAL
**
** ^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
** passed through to [sqlite3_vmprintf()] to generate the final output string.
**
** The sqlite3_log() interface is intended for use by extensions such as