vdata_id	IN:	Vdata identifier returned by VSattach
	field_index	IN:	Index of the field
	attr_index	IN:	Index of the attribute
	values	OUT:	Buffer for the attribute values

	Purpose	Retrieves the attribute values of a vdata or vdata field.
	Return value	Returns SUCCEED (or 0) if successful and FAIL (or -1) otherwise.
	Description	VSgetattr retrieves the attribute values of the vdata identified by the parameter vdata_id or the vdata field specified by the field index, field_index, into the buffer values.
		If field_index is set to _HDF_VDATA (or -1), the value of the attribute attached to the vdata is returned. If field_index is set to the field index, attribute attached to a vdata field is returned. Field index is a nonnegative integer less than the total number of the vdata fields. The number of vdata fields is returned by VFnfields
		Attribute to be retrieved is specified by its index, attr_index. Index is a nonnegative integer less than the total number of the vdata or vdata field attributes. Use VSfnattrs to find the number of the vdata or vdata field attributes.

	FORTRAN	integer function vsfgnat(vdata_id, field_index, attr_index, values)
		integer vdata_id, field_index, attr_index
		<valid numeric data type> values(*)
		integer function vsfgcat(vdata_id, field_index, attr_index, values)
		integer vdata_id, field_index, attr_index
		character*(*) values