an_id	IN:	AN interface identifier returned by ANstart
	index	IN:	Location of the annotation in the file
	annot_type	IN:	Type of the annotation

	Purpose	Obtains an existing annotation.
	Return value	Returns the annotation identifier (ann_id) if successful or FAIL (or -1) otherwise.
	Description	ANselect obtains the identifier of the annotation specified by its index, index, and by its annotation type, annot_type.
		The parameter index is a nonnegative integer and is less than the total number of annotations of type annot_type in the file. Use ANfileinfo to obtain the total number of annotations of each type in the file.
		Valid values of annot_type are AN_DATA_LABEL (or 0), AN_DATA_DESC (or 1), AN_FILE_LABEL (or 2), and AN_FILE_DESC (or 3).

	FORTRAN	integer function afselect(an_id, index, annot_type)
		integer an_id, index
		integer annot_type