an_id	IN:	AN interface identifier returned by ANstart
	annot_type	IN:	Type of the annotation
	obj_tag	IN:	Tag of the object
	obj_ref	IN:	Reference number of the object
	ann_list	OUT:	Buffer for the annotation identifiers

	Purpose	Retrieves the annotation identifiers of an object.
	Return value	Returns SUCCEED (or 0) or FAIL (or -1) otherwise.
	Description	ANannlist obtains a list of identifiers of the annotations that are of the type specified by the parameter annot_type and are attached to the object identified by its tag, obj_tag, and its reference number, obj_ref.
		Since this routine is implemented only to obtain the identifiers of data annotations and not file annotations, the valid values of annot_type are AN_DATA_LABEL (or 0) and AN_DATA_DESC (or 1). To obtain file annotation identifiers, use ANfileinfo to determine the number of file labels and descriptions, and then use ANselect to obtain each file annotation identifier.
		Sufficient space must be allocated for ann_list to hold the list of annotation identifiers. This can be done by using ANnumann to obtain the number of annotation identifiers to be retrieved, and then allocating memory for ann_list using this number.

	FORTRAN	integer function afannlist(an_id, annot_type, obj_tag, obj_ref, ann_list)
		integer ann_list(*)
		integer an_id, obj_tag, obj_ref, annot_type