mv_sds_to_external.f

      program  write_extfile

      implicit none 

C

C     Parameter declaration.

C

      character*7  FILE_NAME

      character*11 EXT_FILE_NAME

      integer      OFFSET

      integer      DFACC_WRITE

      parameter   (FILE_NAME      = 'SDS.hdf',

     +             EXT_FILE_NAME  = 'ExternalSDS',

     +             OFFSET         = 24,

     +             DFACC_WRITE    = 2)

C

C     Function declaration.

C

      integer sfstart, sfselect, sfsextf, sfendacc, sfend

C

C**** Variable declaration *******************************************

C

      integer sd_id, sds_id, sds_index, offset

      integer status

C

C**** End of variable declaration ************************************

C

C

C     Open the HDF file and initialize the SD interface.

C

      sd_id = sfstart(FILE_NAME, DFACC_WRITE)

C

C     Select the first data set.

C

      sds_index = 0

      sds_id = sfselect(sd_id, sds_index)

C

C     Create a file with the name EXT_FILE_NAME and move the data set

C     into it, starting at byte location OFFSET.

C

      status = sfsextf(sds_id, EXT_FILE_NAME, OFFSET)

C

C     Terminate access to the data set. 

C

      status = sfendacc(sds_id)

C

C     Terminate access to the SD interface and close the file. 

C

      status = sfend(sd_id)

      end