PF_WRITE
while (pty->pt_flags & PF_WRITE) {
pty->pt_flags |= PF_WRITE;
pty->pt_flags &= ~(PF_WRITE | PF_WWRITE);
pty->pt_flags &= ~(PF_WRITE | PF_WWRITE);
while (pty->pt_flags & PF_WRITE) {
pty->pt_flags |= PF_WRITE;
pty->pt_flags &= ~(PF_WRITE | PF_WWRITE);