obj_id	IN:	Identifier of the object to which the attribute is attached
	attr_name	IN:	Name of the attribute

	Purpose	Finds the index of an attribute given its name.
	Return value	Returns the index if successful and FAIL (or -1) otherwise.
	Description	SDfindattr retrieves the index of the object's attribute with the name specified by the parameter attr_name.
		The attribute is attached to the object specified by the parameter obj_id. 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.
		Wildcard characters are not allowed in the parameter attr_name. SDfindattr searches for the name specified in the parameter attr_name in a case-sensitive manner.

	FORTRAN	integer function sffattr(obj_id, attr_name)
		integer obj_id
		character*(*) attr_name