DECLARE
v_device   VARCHAR2 (50);
  v_done     boolean;
BEGIN
  v_device :=      DBMS_BACKUP_RESTORE.deviceallocate(TYPE       => NULL, ident      => 't1');
  dbms_backup_restore.RestoreSetDatafile; 
  dbms_backup_restore.RestoreDatafileTo(dfnumber => 1,toname => '/tmp/SYSTEM01.DBF');
  dbms_backup_restore.RestoreBackupPiece(done => done,handle => '<backup_piece>', params => null);
  dbms_backup_restore.DeviceDeallocate;
 EXCEPTION
  WHEN OTHERS THEN
  DBMS_BACKUP_RESTORE.devicedeallocate;
END;
/