Upper Write service Procedure Sample

The following example shows the code for the upper multiplexer write service procedure:

static int muxuwsrv(queue_t *q)
{
	mblk_t *mp;
	struct mux *muxp;
	muxp = (struct mux *)q->q_ptr;

	if (!muxbot) {
			flushq(q, FLUSHALL);
			return (0);
	}
	if (muxerr) {
			flushq(q, FLUSHALL);
			return (0);
	}
	while (mp = getq(q)) {
			if (canputnext(muxbot))
				putnext(muxbot, mp);
			else {
				putbq(q, mp);
				return(0);
			}
	}
	return (0);
}

As long as there is a stream still linked under the multiplexer and there are no errors, the service procedure will take a message off the queue and send it downstream, if flow control allows.