PIPE_WANTW
if (rpipe->pipe_state & PIPE_WANTW) {
rpipe->pipe_state &= ~PIPE_WANTW;
if (rpipe->pipe_state & PIPE_WANTW) {
rpipe->pipe_state &= ~PIPE_WANTW;
wpipe->pipe_state |= PIPE_WANTW;
cpipe->pipe_state &= ~(PIPE_WANTD | PIPE_WANTR | PIPE_WANTW);
(kf->pipe_state & PIPE_WANTW) ? "W" : "",