msg_loop
err = msg_loop(rx_fd, iov_count, iov_buf,
err = msg_loop(c1, iov_count, iov_buf,
rc = msg_loop(0, lsd, (void *) addr, alen, args);
rc = msg_loop(0, csd, (void *) addr, alen, args);
rc = msg_loop(1, sd, addr, alen, args);