**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.418 2008/02/19 15:20:44 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#ifdef SQLITE_ENABLE_FTS3
# include "fts3.h"
#endif

................................................................................
  sqlite3HashInit(&db->aModule, SQLITE_HASH_STRING, 0);
#endif

  db->pVfs = sqlite3_vfs_find(zVfs);
  if( !db->pVfs ){
    rc = SQLITE_ERROR;
    db->magic = SQLITE_MAGIC_SICK;
    sqlite3Error(db, rc, "no such vfs: %s", (zVfs?zVfs:"(null)"));
    goto opendb_out;
  }

  /* Add the default collation sequence BINARY. BINARY works for both UTF-8
  ** and UTF-16, so add a version for each to avoid any unnecessary
  ** conversions. The only error that can occur here is a malloc() failure.
  */
  if( createCollation(db, "BINARY", SQLITE_UTF8, 0, binCollFunc, 0) ||
      createCollation(db, "BINARY", SQLITE_UTF16BE, 0, binCollFunc, 0) ||
      createCollation(db, "BINARY", SQLITE_UTF16LE, 0, binCollFunc, 0) ||
      createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0) ||

      (db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 6, 0))==0 
  ){
    assert( db->mallocFailed );
    db->magic = SQLITE_MAGIC_SICK;
    goto opendb_out;
  }

................................................................................
#ifdef SQLITE_DEFAULT_LOCKING_MODE
  db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
  sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
                          SQLITE_DEFAULT_LOCKING_MODE);
#endif

opendb_out:
  if( db && db->mutex ){

    sqlite3_mutex_leave(db->mutex);
  }
  if( SQLITE_NOMEM==(rc = sqlite3_errcode(db)) ){
    sqlite3_close(db);
    db = 0;
  }
  *ppDb = db;
................................................................................
  *ppDb = 0;
  pVal = sqlite3ValueNew(0);
  sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
  zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
  if( zFilename8 ){
    rc = openDatabase(zFilename8, ppDb,
                      SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);

    if( rc==SQLITE_OK && *ppDb ){
      rc = sqlite3_exec(*ppDb, "PRAGMA encoding = 'UTF-16'", 0, 0, 0);
      if( rc!=SQLITE_OK ){
        sqlite3_close(*ppDb);
        *ppDb = 0;
      }
    }
  }

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.419 2008/02/21 02:09:45 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
#ifdef SQLITE_ENABLE_FTS3
# include "fts3.h"
#endif

................................................................................
  sqlite3HashInit(&db->aModule, SQLITE_HASH_STRING, 0);
#endif

  db->pVfs = sqlite3_vfs_find(zVfs);
  if( !db->pVfs ){
    rc = SQLITE_ERROR;
    db->magic = SQLITE_MAGIC_SICK;
    sqlite3Error(db, rc, "no such vfs: %s", zVfs);
    goto opendb_out;
  }

  /* Add the default collation sequence BINARY. BINARY works for both UTF-8
  ** and UTF-16, so add a version for each to avoid any unnecessary
  ** conversions. The only error that can occur here is a malloc() failure.
  */
  createCollation(db, "BINARY", SQLITE_UTF8, 0, binCollFunc, 0);
  createCollation(db, "BINARY", SQLITE_UTF16BE, 0, binCollFunc, 0);
  createCollation(db, "BINARY", SQLITE_UTF16LE, 0, binCollFunc, 0);
  createCollation(db, "RTRIM", SQLITE_UTF8, (void*)1, binCollFunc, 0);
  if( db->mallocFailed ||
      (db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 6, 0))==0 
  ){
    assert( db->mallocFailed );
    db->magic = SQLITE_MAGIC_SICK;
    goto opendb_out;
  }

................................................................................
#ifdef SQLITE_DEFAULT_LOCKING_MODE
  db->dfltLockMode = SQLITE_DEFAULT_LOCKING_MODE;
  sqlite3PagerLockingMode(sqlite3BtreePager(db->aDb[0].pBt),
                          SQLITE_DEFAULT_LOCKING_MODE);
#endif

opendb_out:
  if( db ){
    assert( db->mutex!=0 );
    sqlite3_mutex_leave(db->mutex);
  }
  if( SQLITE_NOMEM==(rc = sqlite3_errcode(db)) ){
    sqlite3_close(db);
    db = 0;
  }
  *ppDb = db;
................................................................................
  *ppDb = 0;
  pVal = sqlite3ValueNew(0);
  sqlite3ValueSetStr(pVal, -1, zFilename, SQLITE_UTF16NATIVE, SQLITE_STATIC);
  zFilename8 = sqlite3ValueText(pVal, SQLITE_UTF8);
  if( zFilename8 ){
    rc = openDatabase(zFilename8, ppDb,
                      SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0);
    assert( *ppDb || rc==SQLITE_NOMEM );
    if( rc==SQLITE_OK ){
      rc = sqlite3_exec(*ppDb, "PRAGMA encoding = 'UTF-16'", 0, 0, 0);
      if( rc!=SQLITE_OK ){
        sqlite3_close(*ppDb);
        *ppDb = 0;
      }
    }
  }

** 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.
**
** @(#) $Id: sqlite.h.in,v 1.285 2008/02/14 23:24:16 drh Exp $
*/
#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++.
................................................................................
**
** {F12717} If the filename argument to [sqlite3_open()], [sqlite3_open16()],
**          or [sqlite3_open_v2()] is ":memory:", then an private,
**          ephemeral, in-memory database is created for the connection.
**          <todo>Is SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE required
**          in sqlite3_open_v2()?</todo>
**
** {F12719} If the filename is an empty string, then a private, ephermeral
**          on-disk database will be created.
**          <todo>Is SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE required
**          in sqlite3_open_v2()?</todo>
**
** {F12721} The [database connection] created by 
**          [sqlite3_open_v2(F,D,G,V)] will use the
**          [sqlite3_vfs] object identified by the V parameter, or
**          the default [sqlite3_vfs] object is V is a NULL pointer.
................................................................................
** {F13812} The [sqlite3_column_double(S,N)] interface converts the
**          Nth column in the current row of the result set for
**          [prepared statement] S into a floating point value and
**          returns a copy of that value.
**
** {F13815} The [sqlite3_column_int(S,N)] interface converts the
**          Nth column in the current row of the result set for
**          [prepared statement] S into a 32-bit signed integer and
**          returns a copy of that integer.
**
** {F13818} The [sqlite3_column_int64(S,N)] interface converts the
**          Nth column in the current row of the result set for
**          [prepared statement] S into a 64-bit signed integer and
**          returns a copy of that integer.
**
** {F13821} The [sqlite3_column_text(S,N)] interface converts the
................................................................................
**
** {F16103} The [sqlite3_create_function16()] interface behaves exactly
**          like [sqlite3_create_function()] in every way except that it
**          interprets the zFunctionName argument as
**          zero-terminated UTF-16 native byte order instead of as a
**          zero-terminated UTF-8.
**
** {F16106} 


















































*/
int sqlite3_create_function(
  sqlite3 *db,
  const char *zFunctionName,
  int nArg,
  int eTextRep,
  void *pApp,
................................................................................
**
** These routines must be called from the same thread as
** the SQL function that supplied the sqlite3_value* parameters.
** Or, if the sqlite3_value* argument comes from the [sqlite3_column_value()]
** interface, then these routines should be called from the same thread
** that ran [sqlite3_column_value()].
**






























































*/
const void *sqlite3_value_blob(sqlite3_value*);
int sqlite3_value_bytes(sqlite3_value*);
int sqlite3_value_bytes16(sqlite3_value*);
double sqlite3_value_double(sqlite3_value*);
int sqlite3_value_int(sqlite3_value*);
sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
................................................................................
int sqlite3_value_numeric_type(sqlite3_value*);

/*
** CAPI3REF: Obtain Aggregate Function Context {F16210}
**
** The implementation of aggregate SQL functions use this routine to allocate
** a structure for storing their state.  
** {F16211} The first time the sqlite3_aggregate_context() routine is
** is called for a particular aggregate, SQLite allocates nBytes of memory
** zeros that memory, and returns a pointer to it.
** {F16212} On second and subsequent calls to sqlite3_aggregate_context()
** for the same aggregate function index, the same buffer is returned. {END}
** The implementation
** of the aggregate can use the returned buffer to accumulate data.
**
** {F16213} SQLite automatically frees the allocated buffer when the aggregate
** query concludes. {END}
**
** The first parameter should be a copy of the 
** [sqlite3_context | SQL function context] that is the first
** parameter to the callback routine that implements the aggregate
** function.
**
** This routine must be called from the same thread in which
** the aggregate SQL function is running.





















*/
void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);

/*
** CAPI3REF: User Data For Functions {F16240}
**
** {F16241} The sqlite3_user_data() interface returns a copy of
** the pointer that was the pUserData parameter (the 5th parameter)
** of the the [sqlite3_create_function()]
** and [sqlite3_create_function16()] routines that originally
** registered the application defined function. {END}
**
** {U16243} This routine must be called from the same thread in which
** the application-defined function is running.








*/
void *sqlite3_user_data(sqlite3_context*);

/*
** CAPI3REF: Function Auxiliary Data {F16270}
**
** The following two functions may be used by scalar SQL functions to
................................................................................
** be used, for example, to add a regular-expression matching scalar
** function. The compiled version of the regular expression is stored as
** meta-data 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.
**
** {F16271}
** The sqlite3_get_auxdata() interface returns a pointer to the meta-data
** associated by the sqlite3_set_auxdata() function with the Nth argument
** value to the application-defined function.
** {F16272} If no meta-data has been ever been set for the Nth
** argument of the function, or if the cooresponding function parameter
** has changed since the meta-data was set, then sqlite3_get_auxdata()
** returns a NULL pointer.
**
** {F16275} The sqlite3_set_auxdata() interface saves the meta-data
** pointed to by its 3rd parameter as the meta-data for the N-th
** argument of the application-defined function. {END} Subsequent
** calls to sqlite3_get_auxdata() might return this data, if it has
** not been destroyed. 
** {F16277} If it is not NULL, SQLite will invoke the destructor 
** function given by the 4th parameter to sqlite3_set_auxdata() on
** the meta-data when the corresponding function parameter changes
** or when the SQL statement completes, whichever comes first. {END}





**
** In practice, meta-data is preserved between function calls for
** expressions that are constant at compile time. This includes literal
** values and SQL variables.
**
** These routines must be called from the same thread in which
** the SQL function is running.



























*/
void *sqlite3_get_auxdata(sqlite3_context*, int N);
void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));


/*
** CAPI3REF: Constants Defining Special Destructor Behavior {F10280}
................................................................................
** These functions work very much like the 
** [sqlite3_bind_blob | sqlite3_bind_*] family of functions used
** to bind values to host parameters in prepared statements.
** Refer to the
** [sqlite3_bind_blob | sqlite3_bind_* documentation] for
** additional information.
**
** {F16402} 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. 
** {F16403} The sqlite3_result_zeroblob() inerfaces 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.
**
** {F16407} The sqlite3_result_double() interface sets the result from
** an application defined function to be a floating point value specified
** by its 2nd argument.
**
** {F16409} The sqlite3_result_error() and sqlite3_result_error16() functions
** cause the implemented SQL function to throw an exception.
** {F16411} 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. {F16412} SQLite interprets the error
** message string from sqlite3_result_error() as UTF8.  {F16413} SQLite
** interprets the string from sqlite3_result_error16() as UTF16 in native
** byte order.  {F16414} 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.
** {F16415} 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.
** {F16417} The sqlite3_result_error() and sqlite3_result_error16()
** routines make a copy private copy of the error message text before
** they return.  {END} 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. 
**
** {F16421} The sqlite3_result_toobig() interface causes SQLite
** to throw an error indicating that a string or BLOB is to long
** to represent.  {F16422} The sqlite3_result_nomem() interface
** causes SQLite to throw an exception indicating that the a
** memory allocation failed.
**
** {F16431} 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.
** {F16432} 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.
**
** {F16437} The sqlite3_result_null() interface sets the return value
** of the application-defined function to be NULL.
**
** {F16441} 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.
** {F16442} SQLite takes the text result from the application from
** the 2nd parameter of the sqlite3_result_text* interfaces.
** {F16444} 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.
** {F16447} 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.
** {F16451} 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.
** {F16453} If the 4th parameter to the sqlite3_result_text* interfaces
** or sqlite3_result_blob is the special constant SQLITE_STATIC, then
** SQLite assumes that the text or blob result is constant space and
** does not copy the space or call a destructor when it has
** finished using that result.
** {F16454} 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.
**
** {F16461} The sqlite3_result_value() interface sets the result of
** the application-defined function to be a copy the [sqlite3_value]
** object specified by the 2nd parameter.  {F16463} The
** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
** so that [sqlite3_value] specified in the parameter may change or
** be deallocated after sqlite3_result_value() returns without harm.
**
** {U16491} These routines are called from within the different thread 
** than the one containing the application-defined function that recieved
** the [sqlite3_context] pointer, the results are undefined.































































































*/
void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
void sqlite3_result_double(sqlite3_context*, double);
void sqlite3_result_error(sqlite3_context*, const char*, int);
void sqlite3_result_error16(sqlite3_context*, const void*, int);
void sqlite3_result_error_toobig(sqlite3_context*);
void sqlite3_result_error_nomem(sqlite3_context*);
................................................................................
void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
void sqlite3_result_zeroblob(sqlite3_context*, int n);

/*
** CAPI3REF: Define New Collating Sequences {F16600}
**
** {F16601}
** These functions are used to add new collation sequences to the
** [sqlite3*] handle specified as the first argument. 
**
** {F16602}
** 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(). {F16603} In all cases
** the name is passed as the second function argument.
**
** {F16604}
** 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. {F16605} The
** third argument might also be [SQLITE_UTF16_ALIGNED] to indicate that
** the routine expects pointers to 16-bit word aligned strings
** of UTF16 in the native byte order of the host computer.
**
** {F16607}
** A pointer to the user supplied routine must be passed as the fifth
** argument. {F16609} If it is NULL, this is the same as deleting the collation
** sequence (so that SQLite cannot call it anymore).
** {F16611} Each time the application
** supplied function is invoked, it is passed a copy of the void* passed as
** the fourth argument to sqlite3_create_collation() or
** sqlite3_create_collation16() as its first parameter.
**
** {F16612}
** 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. {END} 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).
**
** {F16615}
** The sqlite3_create_collation_v2() works like sqlite3_create_collation()
** excapt that it takes an extra argument which is a destructor for
** the collation.  {F16617} 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().
** {F16618}  Collations are destroyed when
** they are overridden by later calls to the collation creation functions
** or when the [sqlite3*] database handle is closed using [sqlite3_close()].

















































*/
int sqlite3_create_collation(
  sqlite3*, 
  const char *zName, 
  int eTextRep, 
  void*,
  int(*xCompare)(void*,int,const void*,int,const void*)
................................................................................
  void*,
  int(*xCompare)(void*,int,const void*,int,const void*)
);

/*
** CAPI3REF: Collation Needed Callbacks {F16700}
**
** {F16701}
** To avoid having to register all collation sequences before a database
** can be used, a single callback function may be registered with the
** database handle to be called whenever an undefined collation sequence is
** required.
**
** {F16702}
** 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. {F16703} If sqlite3_collation_needed16() is used, the names
** are passed as UTF-16 in machine native byte order. {F16704} A call to either
** function replaces any existing callback.
**
** {F16705} When the callback is invoked, the first argument passed is a copy
** of the second argument to sqlite3_collation_needed() or
** sqlite3_collation_needed16(). {F16706} The second argument is the database
** handle.  {F16707} The third argument is one of [SQLITE_UTF8],
** [SQLITE_UTF16BE], or [SQLITE_UTF16LE], indicating the most
** desirable form of the collation sequence function required.
** {F16708} The fourth parameter is the name of the
** required collation sequence. {END}
**
** The callback function should register the desired collation using
** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
** [sqlite3_create_collation_v2()].





















*/
int sqlite3_collation_needed(
  sqlite3*, 
  void*, 
  void(*)(void*,sqlite3*,int eTextRep,const char*)
);
int sqlite3_collation_needed16(
................................................................................
  sqlite3 *db,                   /* Database to be rekeyed */
  const void *pKey, int nKey     /* The new key */
);

/*
** CAPI3REF:  Suspend Execution For A Short Time {F10530}
**
** {F10531} The sqlite3_sleep() function
** causes the current thread to suspend execution
** for at least a number of milliseconds specified in its parameter.
**
** {F10532} If the operating system does not support sleep requests with 
** millisecond time resolution, then the time will be rounded up to 
** the nearest second. {F10533} The number of milliseconds of sleep actually 
** requested from the operating system is returned.
**
** {F10534} SQLite implements this interface by calling the xSleep()
** method of the default [sqlite3_vfs] object. {END}











*/
int sqlite3_sleep(int);

/*
** CAPI3REF:  Name Of The Folder Holding Temporary Files {F10310}
**
** If this global variable is made to point to a string which is
................................................................................
** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
** transaction might be rolled back automatically.  The only way to
** find out if SQLite automatically rolled back the transaction after
** an error is to use this function.
**
** INVARIANTS:
**
** {F12931} The [sqlite3_get_autocommit()] interface returns non-zero or
**          zero if the given database connection is or is not in autocommit
**          mode, respectively.
**
** {F12932} Autocommit mode is on by default.
**
** {F12933} Autocommit mode is disabled by a successful [BEGIN] statement.
**
** {F12934} Autocommit mode is enabled by a successful [COMMIT] or [ROLLBACK]
................................................................................
**          is undefined.
*/
int sqlite3_get_autocommit(sqlite3*);

/*
** CAPI3REF:  Find The Database Handle Of A Prepared Statement {F13120}
**
** {F13121} The sqlite3_db_handle interface
** returns the [sqlite3*] database handle to which a
** [prepared statement] belongs.
** {F13122} the database handle returned by sqlite3_db_handle
** is the same database handle that was
** the first argument to the [sqlite3_prepare_v2()] or its variants
** that was used to create the statement in the first place.






*/
sqlite3 *sqlite3_db_handle(sqlite3_stmt*);


/*
** CAPI3REF: Commit And Rollback Notification Callbacks {F12950}
**
** {F12951} The sqlite3_commit_hook() interface registers a callback
** function to be invoked whenever a transaction is committed.
** {F12952} Any callback set by a previous call to sqlite3_commit_hook()
** for the same database connection is overridden.
** {F12953} The sqlite3_rollback_hook() interface registers a callback
** function to be invoked whenever a transaction is committed.
** {F12954} Any callback set by a previous call to sqlite3_commit_hook()
** for the same database connection is overridden.
** {F12956} The pArg argument is passed through
** to the callback.  {F12957} If the callback on a commit hook function 
** returns non-zero, then the commit is converted into a rollback.
**
** {F12958} If another function was previously registered, its
** pArg value is returned.  Otherwise NULL is returned.
**
** {F12959} Registering a NULL function disables the callback.
**
** {F12961} 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.
** {F12962} The rollback callback is not invoked if a transaction is
** automatically rolled back because the database connection is closed.
** {F12964} The rollback callback is not invoked if a transaction is
** rolled back because a commit callback returned non-zero.
** <todo> Check on this </todo> {END}
**
** These are experimental interfaces and are subject to change.





































*/
void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);

/*
** CAPI3REF: Data Change Notification Callbacks {F12970}
**
** {F12971} 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.
** {F12972} Any callback set by a previous call to this function for the same 
** database connection is overridden.
**
** {F12974} The second argument is a pointer to the function to invoke when a 
** row is updated, inserted or deleted. 
** {F12976} The first argument to the callback is
** a copy of the third argument to sqlite3_update_hook().
** {F12977} 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.
** {F12978} The third and 
** fourth arguments to the callback contain pointers to the database and 
** table name containing the affected row.
** {F12979} The final callback parameter is 
** the rowid of the row.
** {F12981} In the case of an update, this is the rowid after 
** the update takes place.
**
** {F12983} The update hook is not invoked when internal system tables are
** modified (i.e. sqlite_master and sqlite_sequence).
**
** {F12984} If another function was previously registered, its pArg value
** is returned.  {F12985} Otherwise NULL is returned.































*/
void *sqlite3_update_hook(
  sqlite3*, 
  void(*)(void *,int ,char const *,char const *,sqlite3_int64),
  void*
);

/*
** CAPI3REF:  Enable Or Disable Shared Pager Cache {F10330}
**
** {F10331}
** This routine enables or disables the sharing of the database cache
** and schema data structures between connections to the same database.
** {F10332}
** Sharing is enabled if the argument is true and disabled if the argument
** is false.
**
** {F10333} Cache sharing is enabled and disabled
** for an entire process. {END} 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.
**
** {F10334}
** The cache sharing mode set by this interface effects all subsequent
** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
** {F10335} Existing database connections continue use the sharing mode
** that was in effect at the time they were opened. {END}
**
** Virtual tables cannot be used with a shared cache.  {F10336} When shared
** cache is enabled, the [sqlite3_create_module()] API used to register
** virtual tables will always return an error. {END}
**
** {F10337} This routine returns [SQLITE_OK] if shared cache was
** enabled or disabled successfully.  {F10338} An [error code]
** is returned otherwise. {END}
**
** {F10339} Shared cache is disabled by default. {END} But this might change in
** future releases of SQLite.  Applications that care about shared
** cache setting should set it explicitly.














*/
int sqlite3_enable_shared_cache(int);

/*
** CAPI3REF:  Attempt To Free Heap Memory {F17340}
**
** {F17341} The sqlite3_release_memory() interface attempts to
** free N bytes of heap memory by deallocating non-essential memory
** allocations held by the database labrary. {END}  Memory used
** to cache database pages to improve performance is an example of
** non-essential memory.  {F16342} sqlite3_release_memory() returns
** the number of bytes actually freed, which might be more or less
** than the amount requested.










*/
int sqlite3_release_memory(int);

/*
** CAPI3REF:  Impose A Limit On Heap Size {F17350}
**
** {F16351} The sqlite3_soft_heap_limit() interface
** places a "soft" limit on the amount of heap memory that may be allocated
** by SQLite. {F16352} 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 made. {END}
**
** {F16353} 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.
**
** {F16354}
** 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.
** {F16355} The default value for the soft heap limit is zero.
**
** SQLite makes a best effort to honor the soft heap limit.  
** {F16356} But if the soft heap limit cannot honored, execution will
** continue without error or notification. {END}  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. {F16357} The value specified for the soft heap limit
** is an upper bound on the total memory allocation for all threads. {END}  In
** version 3.5.0 there is no mechanism for limiting the heap usage for
** individual threads.




























*/
void sqlite3_soft_heap_limit(int);

/*
** CAPI3REF:  Extract Metadata About A Column Of A Table {F12850}
**
** This routine

** 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.
**
** @(#) $Id: sqlite.h.in,v 1.286 2008/02/21 02:09:45 drh Exp $
*/
#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++.
................................................................................
**
** {F12717} If the filename argument to [sqlite3_open()], [sqlite3_open16()],
**          or [sqlite3_open_v2()] is ":memory:", then an private,
**          ephemeral, in-memory database is created for the connection.
**          <todo>Is SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE required
**          in sqlite3_open_v2()?</todo>
**
** {F12719} If the filename is NULL or an empty string, then a private,
**          ephermeral on-disk database will be created.
**          <todo>Is SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE required
**          in sqlite3_open_v2()?</todo>
**
** {F12721} The [database connection] created by 
**          [sqlite3_open_v2(F,D,G,V)] will use the
**          [sqlite3_vfs] object identified by the V parameter, or
**          the default [sqlite3_vfs] object is V is a NULL pointer.
................................................................................
** {F13812} The [sqlite3_column_double(S,N)] interface converts the
**          Nth column in the current row of the result set for
**          [prepared statement] S into a floating point value and
**          returns a copy of that value.
**
** {F13815} The [sqlite3_column_int(S,N)] interface converts the
**          Nth column in the current row of the result set for
**          [prepared statement] S into a 64-bit signed integer and
**          returns the lower 32 bits of that integer.
**
** {F13818} The [sqlite3_column_int64(S,N)] interface converts the
**          Nth column in the current row of the result set for
**          [prepared statement] S into a 64-bit signed integer and
**          returns a copy of that integer.
**
** {F13821} The [sqlite3_column_text(S,N)] interface converts the
................................................................................
**
** {F16103} The [sqlite3_create_function16()] interface behaves exactly
**          like [sqlite3_create_function()] in every way except that it
**          interprets the zFunctionName argument as
**          zero-terminated UTF-16 native byte order instead of as a
**          zero-terminated UTF-8.
**
** {F16106} A successful invocation of
**          the [sqlite3_create_function(D,X,N,E,...)] interface registers
**          or replaces callback functions in [database connection] D
**          used to implement the SQL function named X with N parameters
**          and having a perferred text encoding of E.
**
** {F16109} A successful call to [sqlite3_create_function(D,X,N,E,P,F,S,L)]
**          replaces the P, F, S, and L values from any prior calls with
**          the same D, X, N, and E values.
**
** {F16112} The [sqlite3_create_function(D,X,...)] interface fails with
**          a return code of [SQLITE_ERROR] if the SQL function name X is
**          longer than 255 bytes exclusive of the zero terminator.
**
** {F16118} Either F must be NULL and S and L are non-NULL or else F
**          is non-NULL and S and L are NULL, otherwise
**          [sqlite3_create_function(D,X,N,E,P,F,S,L)] returns [SQLITE_ERROR].
**
** {F16121} The [sqlite3_create_function(D,...)] interface fails with an
**          error code of [SQLITE_BUSY] if there exist [prepared statements]
**          associated with the [database connection] D.
**
** {F16124} The [sqlite3_create_function(D,X,N,...)] interface fails with an
**          error code of [SQLITE_ERROR] if parameter N (specifying the number
**          of arguments to the SQL function being registered) is less
**          than -1 or greater than 127.
**
** {F16127} When N is non-negative, the [sqlite3_create_function(D,X,N,...)]
**          interface causes callbacks to be invoked for the SQL function
**          named X when the number of arguments to the SQL function is
**          exactly N.
**
** {F16130} When N is -1, the [sqlite3_create_function(D,X,N,...)]
**          interface causes callbacks to be invoked for the SQL function
**          named X with any number of arguments.
**
** {F16133} When calls to [sqlite3_create_function(D,X,N,...)]
**          specify multiple implementations of the same function X
**          and when one implementation has N>=0 and the other has N=(-1)
**          the implementation with a non-zero N is preferred.
**
** {F16136} When calls to [sqlite3_create_function(D,X,N,E,...)]
**          specify multiple implementations of the same function X with
**          the same number of arguments N but with different
**          encodings E, then the implementation where E matches the
**          database encoding is preferred.
**
** {F16139} For an aggregate SQL function created using
**          [sqlite3_create_function(D,X,N,E,P,0,S,L)] the finializer
**          function L will always be invoked exactly once if the
**          step function S is called one or more times.
*/
int sqlite3_create_function(
  sqlite3 *db,
  const char *zFunctionName,
  int nArg,
  int eTextRep,
  void *pApp,
................................................................................
**
** These routines must be called from the same thread as
** the SQL function that supplied the sqlite3_value* parameters.
** Or, if the sqlite3_value* argument comes from the [sqlite3_column_value()]
** interface, then these routines should be called from the same thread
** that ran [sqlite3_column_value()].
**
**
** INVARIANTS:
**
** {F15103} The [sqlite3_value_blob(V)] interface converts the
**          [sqlite3_value] object V into a blob and then returns a
**          pointer to the converted value.
**
** {F15106} The [sqlite3_value_bytes(V)] interface returns the
**          number of bytes in the blob or string (exclusive of the
**          zero terminator on the string) that was returned by the
**          most recent call to [sqlite3_value_blob(V)] or
**          [sqlite3_value_text(V)].
**
** {F15109} The [sqlite3_value_bytes16(V)] interface returns the
**          number of bytes in the string (exclusive of the
**          zero terminator on the string) that was returned by the
**          most recent call to [sqlite3_value_text16(V)],
**          [sqlite3_value_text16be(V)], or [sqlite3_value_text16le(V)].
**
** {F15112} The [sqlite3_value_double(V)] interface converts the
**          [sqlite3_value] object V into a floating point value and
**          returns a copy of that value.
**
** {F15115} The [sqlite3_value_int(V)] interface converts the
**          [sqlite3_value] object V into a 64-bit signed integer and
**          returns the lower 32 bits of that integer.
**
** {F15118} The [sqlite3_value_int64(V)] interface converts the
**          [sqlite3_value] object V into a 64-bit signed integer and
**          returns a copy of that integer.
**
** {F15121} The [sqlite3_value_text(V)] interface converts the
**          [sqlite3_value] object V into a zero-terminated UTF-8 
**          string and returns a pointer to that string.
**
** {F15124} The [sqlite3_value_text16(V)] interface converts the
**          [sqlite3_value] object V into a zero-terminated 2-byte
**          aligned UTF-16 native byte order
**          string and returns a pointer to that string.
**
** {F15127} The [sqlite3_value_text16be(V)] interface converts the
**          [sqlite3_value] object V into a zero-terminated 2-byte
**          aligned UTF-16 big-endian
**          string and returns a pointer to that string.
**
** {F15130} The [sqlite3_value_text16le(V)] interface converts the
**          [sqlite3_value] object V into a zero-terminated 2-byte
**          aligned UTF-16 little-endian
**          string and returns a pointer to that string.
**
** {F15133} The [sqlite3_value_type(V)] interface returns
**          one of [SQLITE_NULL], [SQLITE_INTEGER], [SQLITE_FLOAT],
**          [SQLITE_TEXT], or [SQLITE_BLOB] as appropriate for
**          the [sqlite3_value] object V.
**
** {F15136} The [sqlite3_value_numeric_type(V)] interface converts
**          the [sqlite3_value] object V into either an integer or
**          a floating point value if it can do so without loss of
**          information, and returns one of [SQLITE_NULL],
**          [SQLITE_INTEGER], [SQLITE_FLOAT], [SQLITE_TEXT], or
**          [SQLITE_BLOB] as appropriate for
**          the [sqlite3_value] object V after the conversion attempt.
*/
const void *sqlite3_value_blob(sqlite3_value*);
int sqlite3_value_bytes(sqlite3_value*);
int sqlite3_value_bytes16(sqlite3_value*);
double sqlite3_value_double(sqlite3_value*);
int sqlite3_value_int(sqlite3_value*);
sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
................................................................................
int sqlite3_value_numeric_type(sqlite3_value*);

/*
** CAPI3REF: Obtain Aggregate Function Context {F16210}
**
** The implementation of aggregate SQL functions use this routine to allocate
** a structure for storing their state.  
** The first time the sqlite3_aggregate_context() routine is
** is called for a particular aggregate, SQLite allocates nBytes of memory
** zeros that memory, and returns a pointer to it.
** On second and subsequent calls to sqlite3_aggregate_context()
** for the same aggregate function index, the same buffer is returned.
** The implementation
** of the aggregate can use the returned buffer to accumulate data.
**
** SQLite automatically frees the allocated buffer when the aggregate
** query concludes.
**
** The first parameter should be a copy of the 
** [sqlite3_context | SQL function context] that is the first
** parameter to the callback routine that implements the aggregate
** function.
**
** This routine must be called from the same thread in which
** the aggregate SQL function is running.
**
** INVARIANTS:
**
** {F16211} The first invocation of [sqlite3_aggregate_context(C,N)] for
**          a particular instance of an aggregate function (for a particular
**          context C) causes SQLite to allocation N bytes of memory,
**          zero that memory, and return a pointer to the allocationed
**          memory.
**
** {F16213} If a memory allocation error occurs during
**          [sqlite3_aggregate_context(C,N)] then the function returns 0.
**
** {F16215} Second and subsequent invocations of
**          [sqlite3_aggregate_context(C,N)] for the same context pointer C
**          ignore the N parameter and return a pointer to the same
**          block of memory returned by the first invocation.
**
** {F16217} The memory allocated by [sqlite3_aggregate_context(C,N)] is
**          automatically freed on the next call to [sqlite3_reset()]
**          or [sqlite3_finalize()] for the [prepared statement] containing
**          the aggregate function associated with context C.
*/
void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);

/*
** CAPI3REF: User Data For Functions {F16240}
**
** The sqlite3_user_data() interface returns a copy of
** the pointer that was the pUserData parameter (the 5th parameter)
** of the the [sqlite3_create_function()]
** and [sqlite3_create_function16()] routines that originally
** registered the application defined function. {END}
**
** This routine must be called from the same thread in which
** the application-defined function is running.
**
** INVARIANTS:
**
** {F16243} The [sqlite3_user_data(C)] interface returns a copy of the
**          P pointer from the [sqlite3_create_function(D,X,N,E,P,F,S,L)]
**          or [sqlite3_create_function16(D,X,N,E,P,F,S,L)] call that
**          registered the SQL function associated with 
**          [sqlite3_context] C.
*/
void *sqlite3_user_data(sqlite3_context*);

/*
** CAPI3REF: Function Auxiliary Data {F16270}
**
** The following two functions may be used by scalar SQL functions to
................................................................................
** be used, for example, to add a regular-expression matching scalar
** function. The compiled version of the regular expression is stored as
** meta-data 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 meta-data
** associated by the sqlite3_set_auxdata() function with the Nth argument
** value to the application-defined function.
** If no meta-data has been ever been set for the Nth
** argument of the function, or if the cooresponding 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 meta-data
** pointed to by its 3rd parameter as the meta-data 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 meta-data when the corresponding function parameter changes
** or when the SQL statement completes, whichever comes first.
**
** SQLite is free to call the destructor and drop meta-data 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, meta-data is preserved between function calls for
** expressions that are constant at compile time. This includes literal
** values and SQL variables.
**
** These routines must be called from the same thread in which
** the SQL function is running.
**
** INVARIANTS:
**
** {F16272} The [sqlite3_get_auxdata(C,N)] interface returns a pointer
**          to metadata associated with the Nth parameter of the SQL function
**          whose context is C, or NULL if there is no metadata associated
**          with that parameter.
**
** {F16274} The [sqlite3_set_auxdata(C,N,P,D)] interface assigns a metadata
**          pointer P to the Nth parameter of the SQL function with context
**          C.
**
** {F16276} SQLite will invoke the destructor D with a single argument
**          which is the metadata pointer P following a call to
**          [sqlite3_set_auxdata(C,N,P,D)] when SQLite ceases to hold
**          the metadata.
**
** {F16277} SQLite ceases to hold metadata for an SQL function parameter
**          when the value of that parameter changes.
**
** {F16278} When [sqlite3_set_auxdata(C,N,P,D)] is invoked, the destructor
**          is called for any prior metadata associated with the same function
**          context C and parameter N.
**
** {F16279} SQLite will call destructors for any metadata it is holding
**          in a particular [prepared statement] S when either
**          [sqlite3_reset(S)] or [sqlite3_finalize(S)] is called.
*/
void *sqlite3_get_auxdata(sqlite3_context*, int N);
void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));


/*
** CAPI3REF: Constants Defining Special Destructor Behavior {F10280}
................................................................................
** These functions work very much like the 
** [sqlite3_bind_blob | sqlite3_bind_*] family of functions used
** to bind values to host parameters in prepared statements.
** Refer to the
** [sqlite3_bind_blob | sqlite3_bind_* 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() inerfaces 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 UTF8. SQLite
** interprets the string from sqlite3_result_error16() as UTF16 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 copy 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. 
**
** The sqlite3_result_toobig() interface causes SQLite
** to throw an error indicating that a string or BLOB is to long
** to represent.  The sqlite3_result_nomem() interface
** causes SQLite to throw an exception indicating that the 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 sqlite3_result_blob is the special constant SQLITE_STATIC, then
** SQLite assumes that the text or blob result is constant space and
** does not copy the space or call a destructor 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 [sqlite3_value]
** object specified by the 2nd parameter.  The
** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
** so that [sqlite3_value] specified in the parameter may change or
** be deallocated after sqlite3_result_value() returns without harm.
**
** If these routines are called from within the different thread 
** than the one containing the application-defined function that recieved
** the [sqlite3_context] pointer, the results are undefined.
**
** INVARIANTS:
**
** {F16403} The default return value from any SQL function is NULL.
**
** {F16406} The [sqlite3_result_blob(C,V,N,D)] interface changes the
**          return value of function C to be a blob that is N bytes
**          in length and with content pointed to by V.
**
** {F16409} The [sqlite3_result_double(C,V)] interface changes the
**          return value of function C to be the floating point value V.
**
** {F16412} The [sqlite3_result_error(C,V,N)] interface changes the return
**          value of function C to be an exception with error code
**          [SQLITE_ERROR] and a UTF8 error message copied from V up to the
**          first zero byte or until N bytes are read if N is positive.
**
** {F16415} The [sqlite3_result_error16(C,V,N)] interface changes the return
**          value of function C to be an exception with error code
**          [SQLITE_ERROR] and a UTF16 native byte order error message
**          copied from V up to the first zero terminator or until N bytes
**          are read if N is positive.
**
** {F16418} The [sqlite3_result_error_toobig(C)] interface changes the return
**          value of the function C to be an exception with error code
**          [SQLITE_TOOBIG] and an appropriate error message.
**
** {F16421} The [sqlite3_result_error_nomem(C)] interface changes the return
**          value of the function C to be an exception with error code
**          [SQLITE_NOMEM] and an appropriate error message.
**
** {F16424} The [sqlite3_result_error_code(C,E)] interface changes the return
**          value of the function C to be an exception with error code E.
**          The error message text is unchanged.
**
** {F16427} The [sqlite3_result_int(C,V)] interface changes the
**          return value of function C to be the 32-bit integer value V.
**
** {F16430} The [sqlite3_result_int64(C,V)] interface changes the
**          return value of function C to be the 64-bit integer value V.
**
** {F16433} The [sqlite3_result_null(C)] interface changes the
**          return value of function C to be NULL.
**
** {F16436} The [sqlite3_result_text(C,V,N,D)] interface changes the
**          return value of function C to be the UTF8 string
**          V up through the first zero or until N bytes are read if N
**          is positive.
**
** {F16439} The [sqlite3_result_text16(C,V,N,D)] interface changes the
**          return value of function C to be the UTF16 native byte order
**          string  V up through the first zero or until N bytes are read if N
**          is positive.
**
** {F16442} The [sqlite3_result_text16be(C,V,N,D)] interface changes the
**          return value of function C to be the UTF16 big-endian
**          string  V up through the first zero or until N bytes are read if N
**          is positive.
**
** {F16445} The [sqlite3_result_text16le(C,V,N,D)] interface changes the
**          return value of function C to be the UTF16 little-endian
**          string  V up through the first zero or until N bytes are read if N
**          is positive.
**
** {F16448} The [sqlite3_result_value(C,V)] interface changes the
**          return value of function C to be [sqlite3_value] object V.
**
** {F16451} The [sqlite3_result_zeroblob(C,N)] interface changes the
**          return value of function C to be an N-byte blob of all zeros.
**
** {F16454} The [sqlite3_result_error()] and [sqlite3_result_error16()]
**          interfaces make a copy of their error message strings before
**          returning.
**
** {F16457} If the D destructor parameter to [sqlite3_result_blob(C,V,N,D)],
**          [sqlite3_result_text(C,V,N,D)], [sqlite3_result_text16(C,V,N,D)],
**          [sqlite3_result_text16be(C,V,N,D)], or
**          [sqlite3_result_text16le(C,V,N,D)] is the constant [SQLITE_STATIC]
**          then no destructor is ever called on the pointer V and SQLite
**          assumes that V is immutable.
**
** {F16460} If the D destructor parameter to [sqlite3_result_blob(C,V,N,D)],
**          [sqlite3_result_text(C,V,N,D)], [sqlite3_result_text16(C,V,N,D)],
**          [sqlite3_result_text16be(C,V,N,D)], or
**          [sqlite3_result_text16le(C,V,N,D)] is the constant
**          [SQLITE_TRANSIENT] then the interfaces makes a copy of the
**          content of V and retains the copy.
**
** {F16463} If the D destructor parameter to [sqlite3_result_blob(C,V,N,D)],
**          [sqlite3_result_text(C,V,N,D)], [sqlite3_result_text16(C,V,N,D)],
**          [sqlite3_result_text16be(C,V,N,D)], or
**          [sqlite3_result_text16le(C,V,N,D)] is some value other than
**          the constants [SQLITE_STATIC] and [SQLITE_TRANSIENT] then 
**          SQLite will invoke the destructor D with V as its only argument
**          when it has finished with the V value.
*/
void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
void sqlite3_result_double(sqlite3_context*, double);
void sqlite3_result_error(sqlite3_context*, const char*, int);
void sqlite3_result_error16(sqlite3_context*, const void*, int);
void sqlite3_result_error_toobig(sqlite3_context*);
void sqlite3_result_error_nomem(sqlite3_context*);
................................................................................
void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
void sqlite3_result_zeroblob(sqlite3_context*, int n);

/*
** CAPI3REF: Define New Collating Sequences {F16600}
**

** These functions are used to add new collation sequences to the
** [sqlite3*] handle 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_ALIGNED] to indicate that
** the routine expects pointers to 16-bit word aligned strings
** of UTF16 in the native byte order of the host computer.
**

** 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 a copy of the void* passed as
** the fourth argument to sqlite3_create_collation() or
** sqlite3_create_collation16() as its first parameter.
**

** 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. {END} 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()
** excapt 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 [sqlite3*] database handle is closed using [sqlite3_close()].
**
** INVARIANTS:
**
** {F16603} A successful call to the
**          [sqlite3_create_collation_v2(B,X,E,P,F,D)] interface
**          registers function F as the comparison function used to
**          implement collation X on [database connection] B for
**          databases having encoding E.
**
** {F16604} SQLite understands the X parameter to
**          [sqlite3_create_collation_v2(B,X,E,P,F,D)] as a zero-terminated
**          UTF-8 string in which case is ignored for ASCII characters and
**          is significant for non-ASCII characters.
**
** {F16606} Successive calls to [sqlite3_create_collation_v2(B,X,E,P,F,D)]
**          with the same values for B, X, and E, override prior values
**          of P, F, and D.
**
** {F16609} The destructor D in [sqlite3_create_collation_v2(B,X,E,P,F,D)]
**          is not NULL then it is called with argument P when the
**          collating function is dropped by SQLite.
**
** {F16612} A collating function is dropped when it is overloaded.
**
** {F16615} A collating function is dropped when the database connection
**          is closed using [sqlite3_close()].
**
** {F16618} The pointer P in [sqlite3_create_collation_v2(B,X,E,P,F,D)]
**          is passed through as the first parameter to the comparison
**          function F for all subsequent invocations of F.
**
** {F16621} A call to [sqlite3_create_collation(B,X,E,P,F)] is exactly
**          the same as a call to [sqlite3_create_collation_v2()] with
**          the same parameters and a NULL destructor.
**
** {F16624} Following a [sqlite3_create_collation_v2(B,X,E,P,F,D)],
**          SQLite uses the comparison function F for all text comparison
**          operations on [database connection] B on text values that
**          use the collating sequence name X.
**
** {F16627} The [sqlite3_create_collation16(B,X,E,P,F)] works the same
**          as [sqlite3_create_collation(B,X,E,P,F)] except that the
**          collation name X is understood as UTF-16 in native byte order
**          instead of UTF-8.
**
** {F16630} When multiple comparison functions are available for the same
**          collating sequence, SQLite chooses the one whose text encoding
**          requires the least amount of conversion from the default
**          text encoding of the database.
*/
int sqlite3_create_collation(
  sqlite3*, 
  const char *zName, 
  int eTextRep, 
  void*,
  int(*xCompare)(void*,int,const void*,int,const void*)
................................................................................
  void*,
  int(*xCompare)(void*,int,const void*,int,const void*)
);

/*
** CAPI3REF: Collation Needed Callbacks {F16700}
**

** To avoid having to register all collation sequences before a database
** can be used, a single callback function may be registered with the
** database handle to be called 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. {F16703} If sqlite3_collation_needed16() is used, the names
** are passed as UTF-16 in machine native byte order. A call to either
** function replaces any existing 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
** handle.  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()].
**
** INVARIANTS:
**
** {F16702} A successful call to [sqlite3_collation_needed(D,P,F)]
**          or [sqlite3_collation_needed16(D,P,F)] causes
**          the [database connection] D to invoke callback F with first
**          parameter P whenever it needs a comparison function for a
**          collating sequence that it does not know about.
**
** {F16704} Each successful call to [sqlite3_collation_needed()] or
**          [sqlite3_collation_needed16()] overrides the callback registered
**          on the same [database connection] by prior calls to either
**          interface.
**
** {F16706} The name of the requested collating function passed in the
**          4th parameter to the callback is in UTF-8 if the callback
**          was registered using [sqlite3_collation_needed()] and
**          is in UTF-16 native byte order if the callback was
**          registered using [sqlite3_collation_needed16()].
**
** 
*/
int sqlite3_collation_needed(
  sqlite3*, 
  void*, 
  void(*)(void*,sqlite3*,int eTextRep,const char*)
);
int sqlite3_collation_needed16(
................................................................................
  sqlite3 *db,                   /* Database to be rekeyed */
  const void *pKey, int nKey     /* The new key */
);

/*
** CAPI3REF:  Suspend Execution For A Short Time {F10530}
**
** 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.
**
** INVARIANTS:
**
** {F10533} The [sqlite3_sleep(M)] interface invokes the xSleep
**          method of the default [sqlite3_vfs|VFS] in order to
**          suspend execution of the current thread for at least
**          M milliseconds.
**
** {F10536} The [sqlite3_sleep(M)] interface returns the number of
**          milliseconds of sleep actually requested of the operating
**          system, which might be larger than the parameter M.
*/
int sqlite3_sleep(int);

/*
** CAPI3REF:  Name Of The Folder Holding Temporary Files {F10310}
**
** If this global variable is made to point to a string which is
................................................................................
** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
** transaction might be rolled back automatically.  The only way to
** find out if SQLite automatically rolled back the transaction after
** an error is to use this function.
**
** INVARIANTS:
**
** {F12931} The [sqlite3_get_autocommit(D)] interface returns non-zero or
**          zero if the [database connection] D is or is not in autocommit
**          mode, respectively.
**
** {F12932} Autocommit mode is on by default.
**
** {F12933} Autocommit mode is disabled by a successful [BEGIN] statement.
**
** {F12934} Autocommit mode is enabled by a successful [COMMIT] or [ROLLBACK]
................................................................................
**          is undefined.
*/
int sqlite3_get_autocommit(sqlite3*);

/*
** CAPI3REF:  Find The Database Handle Of A Prepared Statement {F13120}
**
** The sqlite3_db_handle interface
** returns the [sqlite3*] database handle to which a
** [prepared statement] belongs.
** The database handle returned by sqlite3_db_handle
** is the same database handle that was
** the first argument to the [sqlite3_prepare_v2()] or its variants
** that was used to create the statement in the first place.
**
** INVARIANTS:
**
** {F13123} The [sqlite3_db_handle(S)] interface returns a pointer
**          to the [database connection] associated with
**          [prepared statement] S.
*/
sqlite3 *sqlite3_db_handle(sqlite3_stmt*);


/*
** CAPI3REF: Commit And Rollback Notification Callbacks {F12950}
**
** The sqlite3_commit_hook() interface registers a callback
** function to be invoked whenever a transaction is 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 committed.
** Any callback set by a previous call to sqlite3_commit_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.
**
** If another function was previously registered, its
** pArg value is returned.  Otherwise NULL is returned.
**
** Registering a NULL function disables the callback.
**
** 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.
** The rollback callback is not invoked if a transaction is
** rolled back because a commit callback returned non-zero.
** <todo> Check on this </todo>
**
** These are experimental interfaces and are subject to change.
**
** INVARIANTS:
**
** {F12951} The [sqlite3_commit_hook(D,F,P)] interface registers the
**          callback function F to be invoked with argument P whenever
**          a transaction commits on [database connection] D.
**
** {F12952} The [sqlite3_commit_hook(D,F,P)] interface returns the P
**          argument from the previous call with the same 
**          [database connection ] D , or NULL on the first call
**          for a particular [database connection] D.
**
** {F12953} Each call to [sqlite3_commit_hook()] overwrites the callback
**          registered by prior calls.
**
** {F12954} If the F argument to [sqlite3_commit_hook(D,F,P)] is NULL
**          then the commit hook callback is cancelled and no callback
**          is invoked when a transaction commits.
**
** {F12955} If the commit callback returns non-zero then the commit is
**          converted into a rollback.
**
** {F12961} The [sqlite3_rollback_hook(D,F,P)] interface registers the
**          callback function F to be invoked with argument P whenever
**          a transaction rolls back on [database connection] D.
**
** {F12962} The [sqlite3_rollback_hook(D,F,P)] interface returns the P
**          argument from the previous call with the same 
**          [database connection ] D , or NULL on the first call
**          for a particular [database connection] D.
**
** {F12963} Each call to [sqlite3_rollback_hook()] overwrites the callback
**          registered by prior calls.
**
** {F12964} If the F argument to [sqlite3_rollback_hook(D,F,P)] is NULL
**          then the rollback hook callback is cancelled and no callback
**          is invoked when a transaction rolls back.
*/
void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);

/*
** CAPI3REF: Data Change Notification Callbacks {F12970}
**
** 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).
**
** If another function was previously registered, its pArg value
** is returned.  Otherwise NULL is returned.
**
** INVARIANTS:
**
** {F12971} The [sqlite3_update_hook(D,F,P)] interface causes callback
**          function F to be invoked with first parameter P whenever
**          a table row is modified, inserted, or deleted on
**          [database connection] D.
**
** {F12973} The [sqlite3_update_hook(D,F,P)] interface returns the value
**          of P for the previous call on the same [database connection] D,
**          or NULL for the first call.
**
** {F12975} If the update hook callback F in [sqlite3_update_hook(D,F,P)]
**          is NULL then the no update callbacks are made.
**
** {F12977} Each call to [sqlite3_update_hook(D,F,P)] overrides prior calls
**          to the same interface on the same [database connection] D.
**
** {F12979} The update hook callback is not invoked when internal system
**          tables such as sqlite_master and sqlite_sequence are modified.
**
** {F12981} The second parameter to the update callback 
**          is one of [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE],
**          depending on the operation that caused the callback to be invoked.
**
** {F12983} The third and fourth arguments to the callback contain pointers
**          to zero-terminated UTF-8 strings which are the names of the
**          database and table that is being updated.

** {F12985} The final callback parameter is the rowid of the row after
**          the change occurs.
*/
void *sqlite3_update_hook(
  sqlite3*, 
  void(*)(void *,int ,char const *,char const *,sqlite3_int64),
  void*
);

/*
** CAPI3REF:  Enable Or Disable Shared Pager Cache {F10330}
**

** This routine enables or disables the sharing of the database cache
** and schema data structures between 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. {END} 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.
**
** Virtual tables cannot be used with a shared cache.   When shared
** cache is enabled, the [sqlite3_create_module()] API used to register
** virtual tables will always return an error.
**
** 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.
**
** INVARIANTS:
** 
** {F10331} A successful invocation of [sqlite3_enable_shared_cache(B)]
**          will enable or disable shared cache mode for any subsequently
**          created [database connection] in the same process.
**
** {F10336} When shared cache is enabled, the [sqlite3_create_module()]
**          interface will always return an error.
**
** {F10337} The [sqlite3_enable_shared_cache(B)] interface returns
**          [SQLITE_OK] if shared cache was enabled or disabled successfully.
**
** {F10339} Shared cache is disabled by default.
*/
int sqlite3_enable_shared_cache(int);

/*
** CAPI3REF:  Attempt To Free Heap Memory {F17340}
**
** The sqlite3_release_memory() interface attempts to
** free N bytes of heap memory by deallocating non-essential memory
** allocations held by the database labrary. {END}  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.
**
** INVARIANTS:
**
** {F17341} The [sqlite3_release_memory(N)] interface attempts to
**          free N bytes of heap memory by deallocating non-essential
**          memory allocations held by the database labrary.
**
** {F16342} The [sqlite3_release_memory(N)] returns the number
**          of bytes actually freed, which might be more or less
**          than the amount requested.
*/
int sqlite3_release_memory(int);

/*
** CAPI3REF:  Impose A Limit On Heap Size {F17350}
**
** 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 made.
**
** 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 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.
**
** INVARIANTS:
**
** {F16351} The [sqlite3_soft_heap_limit(N)] interface places a soft limit
**          of N bytes on the amount of heap memory that may be allocated
**          using [sqlite3_malloc()] or [sqlite3_realloc()] at any point
**          in time.
**
** {F16352} If a call to [sqlite3_malloc()] or [sqlite3_realloc()] would
**          cause the total amount of allocated memory to exceed the
**          soft heap limit, then [sqlite3_release_memory()] is invoked
**          in an attempt to reduce the memory usage prior to proceeding
**          with the memory allocation attempt.
**
** {F16353} Calls to [sqlite3_malloc()] or [sqlite3_realloc()] that trigger
**          attempts to reduce memory usage through the soft heap limit
**          mechanism continue even if the attempt to reduce memory
**          usage is unsuccessful.
**
** {F16354} A negative or zero value for N in a call to
**          [sqlite3_soft_heap_limit(N)] means that there is no soft
**          heap limit and [sqlite3_release_memory()] will only be
**          called when memory is completely exhausted.
**
** {F16355} The default value for the soft heap limit is zero.
**
** {F16358} Each call to [sqlite3_soft_heap_limit(N)] overrides the
**          values set by all prior calls.
*/
void sqlite3_soft_heap_limit(int);

/*
** CAPI3REF:  Extract Metadata About A Column Of A Table {F12850}
**
** This routine

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing all sorts of SQLite interfaces.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test1.c,v 1.290 2008/02/19 18:29:07 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>

/*
................................................................................
  Tcl_Obj *CONST objv[]
){
  const char *zFilename;
  sqlite3 *db;
  int rc;
  char zBuf[100];

  if( objc!=3 && objc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", 
       Tcl_GetString(objv[0]), " filename options-list", 0);
    return TCL_ERROR;
  }

  zFilename = Tcl_GetString(objv[1]);
  rc = sqlite3_open(zFilename, &db);
  
  if( sqlite3TestMakePointerStr(interp, zBuf, db) ) return TCL_ERROR;
  Tcl_AppendResult(interp, zBuf, 0);
  return TCL_OK;
}

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing all sorts of SQLite interfaces.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test1.c,v 1.291 2008/02/21 02:09:45 drh Exp $
*/
#include "sqliteInt.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>

/*
................................................................................
  Tcl_Obj *CONST objv[]
){
  const char *zFilename;
  sqlite3 *db;
  int rc;
  char zBuf[100];

  if( objc!=3 && objc!=2 && objc!=1 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", 
       Tcl_GetString(objv[0]), " filename options-list", 0);
    return TCL_ERROR;
  }

  zFilename = objc>1 ? Tcl_GetString(objv[1]) : 0;
  rc = sqlite3_open(zFilename, &db);
  
  if( sqlite3TestMakePointerStr(interp, zBuf, db) ) return TCL_ERROR;
  Tcl_AppendResult(interp, zBuf, 0);
  return TCL_OK;
}