PIPE_SIGNALR
pipe->pipe_state = PIPE_SIGNALR;
pipe->pipe_state = PIPE_SIGNALR;
&& (ocnt != bp->cnt || (rpipe->pipe_state & PIPE_SIGNALR))) {
rpipe->pipe_state &= ~PIPE_SIGNALR;
wpipe->pipe_state |= PIPE_SIGNALR;