SO_DOMAIN
case SO_DOMAIN:
case SO_DOMAIN:
if (getsockopt(sock_fd, SOL_SOCKET, SO_DOMAIN, &domain, &opt_len))
err = xgetsockopt(s, SOL_SOCKET, SO_DOMAIN, &family, &len);
err = getsockopt(fd, SOL_SOCKET, SO_DOMAIN, &domain, &len);
if (getsockopt(test_fd, SOL_SOCKET, SO_DOMAIN, &test_family, &len))