g_io_add_watch?

[Chris Roberts <croberts bongle co uk>]

Heya,

I'm writing some code using ORBit and glib. I'm trying to receive SNMP 
traps over UDP sockets, however when I try to add a watch on my socket 
with g_io_add_watch, my callback never gets called.
Here's what I've got:
    udp = getprotobyname("udp");
    s = socket(PF_INET, SOCK_DGRAM, udp->p_proto);
    if (s < 0)
        printf("Failed to open socket.\n");


    sa.sin_family=AF_INET;
    sa.sin_addr.s_addr = htonl(INADDR_ANY);
    sa.sin_port = htons(162);


    if (bind(s, (struct sockaddr *)&sa, sizeof(sa)) < 0)
    {
        printf("Can't bind local SNMP port!\n");
        return;
    }
    channel = g_io_channel_unix_new(s);
    g_io_add_watch(channel, G_IO_IN, myfunc, myuserdata);

Now, myfunc never gets called, yet in netstat, I can see the socket 
listening and with data in the receive q.

Any ideas? Have I missed something obvious?
glib is 2.2.1, in case this is a known bug.

Cheers,
Chris.