new

static VALUE
udp_init(int argc, VALUE *argv, VALUE sock)
{
    VALUE arg;
    int socktype = AF_INET;
    int fd;

    rb_secure(3);
    if (rb_scan_args(argc, argv, "01", &arg) == 1) {
        socktype = NUM2INT(arg);
    }
    fd = ruby_socket(socktype, SOCK_DGRAM, 0);
    if (fd < 0) {
        rb_sys_fail("socket(2) - udp");
    }

    return init_sock(sock, fd);
}