throw("runtime: netpollupdate failed")
	}
	pd.user = events
}

// subscribe the fd to the port such that port_getn will return one event.
func netpollarm(pd *pollDesc, mode int) {
	lock(&pd.lock)
	switch mode {
	case 'r':
		netpollupdate(pd, _POLLIN, 0)
	case 'w':
		netpollupdate(pd, _POLLOUT, 0)
	default:
		throw("runtime: bad mode")
	}