filename	IN:	Name of the file
	tag	IN:	Tag of the data object to be assigned the label
	ref	IN:	Reference number the data object to be assigned the label
	label	IN:	Null-terminated label string

	Purpose	Assigns a label to the data object with the given tag/reference number pair.
	Return value	Returns SUCCEED (or 0) if successful and FAIL (or -1) otherwise.

	FORTRAN	integer function daplab(filename, tag, ref, label)
		character*(*) filename, label
		integer tag, ref