format  GfsHn GFS_Open (Sint32 fid)
 Input  fid: File identifier
 Output  None
 Function value  File handle. Returns NULL in case of error.
 Function  Opens the specified file and returns a file handle. 

  format  void GFS_Close (GfsHngfs)
 Input  gfs: File handle
 Output  None
 Function value  None
 Function  Closes the specified file handle. 

 Format  Sint32 GFS_Seek (GfsHngfs, Sint32 off, Sint32 org)
 Input  gfs: File handle
:  off: Amount of access pointer movement (in sectors)
  org: Standard of movement (seek mode: GFS_SEEK_ ~)
 Output  None
 Function value  Position of the access pointer after movement. Negative error code if there was an error.
 Function  Moves the access pointer to a position off sector from org.
:  If movement to a position beyond the end of the file is specified, the file will be moved to that position.
Move the access pointer as if it exists in . . 

  format  Sint32 GFS_Tell (GfsHngfs)
 Input  gfs: File handle
 Output  None
 Function value  Location of the access pointer. Negative error code in case of error.
 Function  Acquires the position of the access pointer.