I don't particularly like all the errno clearing but I suppose we either need to clear it or restore it so the user can distinguish between error and not found conditions.
I do think we need some errno handling in the YP code. For example, the db get in __has_yppw() needs the same handling as __hashpw(). I'm sure there's more. For example, should we clear errno when _yp_check fails and we fall back on the passwd file? - todd
