Null
obfree(obj, Null(obj));
obfree(obj, Null(obj));
obfree(obj, Null(obj));
if ((otmp = uleft) != Null(obj)) {
if ((otmp = uright) != Null(obj)) {
if ((otmp = uwep) != Null(obj)) {
obfree(obj, Null(obj));
enum { Accept, File, Stream, Timer, Wait, Free, Null } type;