Need help generating SIGIO on a unix socket

[Costello]

Hello, I am trying to set up a unix socket such that a SIGIO signal is
automatically generated when data arrives on the socket. I have tried
the following:

	s = socket(AF_UNIX, SOCK_STREAM, 0);
	fcntl(s, F_SETOWN, getpid());

This, however, does not seem to work, i.e. the signal handler that I have
set up does not catch the SIGIO signal. (I know that the signal handler
is working properly and I know that I am getting data on the socket.) I am
doing this on an Apple IIx running A/UX 1.1. Any ideas? Please e-mail to 
me: costello at mitre.org  Thanks! /Roger