/* In case of error, we will go on anyway... */
int err = setsockopt (sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof (on));
IF_DEBUG
/* In case of error, we will go on anyway... */
int err = setsockopt (sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof (on));
IF_DEBUG