%N hexists %F $MIR/src/subs/hio.c
%D Check if an item exists.
%P pjt
%: low-level-i/o
%B
FORTRAN call sequence
        logical function hexists(tno,keyword)
        integer tno
        character keyword*(*)

  Check if a particular item exists in a Miriad data-set.
  By setting the input 'tno' to 0, one can also check for
  existence of any regular file.

  Input:
    tno         The handle of the data set. 0 also allowed.
    keyword     The name of the item or filename to check.
  Output:
    hexists     True if the item exists.                                
