obj_id	IN:	Identifier of the object to which the attribute is attached to
	attr_index	IN:	Index of the attribute
	attr_name	OUT:	Name of the attribute
	data_type	OUT:	Data type of the attribute values
	count	OUT:	Total number of values in the attribute

	Purpose	Retrieves information about an attribute.
	Return value	Returns SUCCEED (or 0) if successful and FAIL (or -1) otherwise.
	Description	SDattrinfo retrieves the name, data type, and number of values of the attribute specified by its index, attr_index, and stores them in the parameters attr_name, data_type, and count, respectively. This routine should be used before reading the values of an attribute with SDreadattr.
		The parameter obj_id can be either an SD interface identifier (sd_id), returned by SDstart, a data set identifier (sds_id), returned by SDselect, or a dimension identifier (dim_id), returned by SDgetdimid.
		Valid values of the parameter attr_index range from 0 to the number of attributes attached to the object - 1.
		Valid values of the parameter data_type can be found in Table 1A of Section I of this manual.

	FORTRAN	integer function sfgainfo(obj_id, attr_index, attr_name, data_type, count)
		character*(*) attr_name
		integer obj_id, attr_index, data_type, count