TF_OPENCLOSE
#define TF_ACTIVITY (TF_GONE|TF_OPENED|TF_HOOK|TF_OPENCLOSE)
{ TF_OPENCLOSE, 'B' },
if (tty_opened(tp) || tp->t_flags & TF_OPENCLOSE) {
tp->t_flags |= TF_OPENCLOSE;
tp->t_flags &= ~TF_OPENCLOSE;
while (tp->t_flags & TF_OPENCLOSE) {
tp->t_flags |= TF_OPENCLOSE;
done: tp->t_flags &= ~TF_OPENCLOSE;
{ TF_OPENCLOSE, 'B' },