format  Sint 32GFS_SetDir (GfsDirTbl * dirtbl);
 Input  dirtbl: Directory information management structure
 Output  None
 Function value  Error code.
 Function  Sets the specified directory information as the current directory.
 directory  The directory information to be used changes depending on the specified directorybltbl. 

dirtbl	Directory information to use
Directory management structure	dirtbl contents
NULL	File management information in CD block

   Uses the CD block file system with GFS_Init when NULL is specified for dirtbl
If you do not declare  , an error will occur.
:  However, a pointer to an appropriate directory information management structure other than NULL in dirtbl
  It is always possible to pass. 

  format  Sint 32GFS_NameToId (Uint8 * fname)
 Input  fname: File name
 Output  None
 Function value  File identifier. Negative error code when an error occurs.
 Function  Returns the file identifier corresponding to the file name. 

  format  const Uint8 * GFS_IdToName (Sint32 fid)
 Input  fid: File identifier
 Output  None
 Function value  Pointer to the file name. NULL if an error occurs.
 Function  Returns a pointer to the file name corresponding to the file identifier. This pointer
:  Points to the conversion table area used by this library. 

  format  Sint32 GFS_GetDirInfo (Sint32 fid, GfsDirId * dirrec)
 Input  fid: File identifier
 Output  dirrec: Directory information
 Function value  Error code
 Function  Directory information is acquired from the file identifier. 

 format  void GFS_Reset (void)
 Input  None
 Output  None
 Function value  None
 Function  Closes all open files and resets the file system.
  (initialize information other than directory information)
 Remarks  If you are using the stream system, close this stream before using this function.
Please execute  .