%N hopen %F $MIR/src/subs/hio.c
%D Open a data set.
%P pjt
%: low-level-i/o
%B
FORTRAN call sequence
        subroutine hopen(tno,name,status,iostat)
        integer tno,iostat
        character name*(*),status*(*)

  This opens a Miriad data-set, and readies it to be read or written.

  Input:
    name        The name of the data set.
    status      Either 'old' or 'new'.
  Output:
    tno         The file handle of the opened data set.
   iostat       I/O status indicator. 0 indicates success. Other values
                are standard system error numbers.                      
