Addrinfo#ip_address

static VALUE
addrinfo_ip_address(VALUE self)
{
    rb_addrinfo_t *rai = get_addrinfo(self);
    int family = ai_get_afamily(rai);
    VALUE vflags;
    VALUE ret;

    if (!IS_IP_FAMILY(family))
        rb_raise(rb_eSocket, "need IPv4 or IPv6 address");

    vflags = INT2NUM(NI_NUMERICHOST|NI_NUMERICSERV);
    ret = addrinfo_getnameinfo(1, &vflags, self);
    return rb_ary_entry(ret, 0);
}