Hi Mikulas, The function body is really verbatim from Andrew's email, as I couldn't think of any good improvements to add to it. I'm not sure how best to credit it to him. I appreciate you looking it over so carefully. Sebastian -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href