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