filename	IN:	Name of the HDF file
	tag	IN:	Tag of the data object assigned the label
	ref	IN:	Reference number of the data object assigned the label
	label_buf	OUT:	Buffer for the label
	buf_len	IN:	Size of the buffer allocated for the label

	Purpose	Reads the label assigned to the data object identified by the given tag and reference number.
	Return value	Returns SUCCEED (or 0) if successful and FAIL (or -1) otherwise.
	Description	The parameter buf_len specifies the storage space available for the label. The length of buf_len must account for the null termination character appended to the annotation.

	FORTRAN	integer function daglab(filename, tag, ref, label_buf, buf_len)
		character*(*) filename, label_buf
		integer tag, ref, buf_len