IPSocket#inspect

static VALUE
ip_inspect(VALUE sock)
{
    VALUE str = rb_call_super(0, 0);
    rb_io_t *fptr = RFILE(sock)->fptr;
    union_sockaddr addr;
    socklen_t len = (socklen_t)sizeof addr;
    ID id;
    if (fptr && fptr->fd >= 0 &&
        getsockname(fptr->fd, &addr.addr, &len) >= 0 &&
        (id = rsock_intern_family(addr.addr.sa_family)) != 0) {
        VALUE family = rb_id2str(id);
        char hbuf[1024], pbuf[1024];
        rb_len_t slen = RSTRING_LEN(str);
        const char last = (slen > 1 && RSTRING_PTR(str)[slen - 1] == '>') ?
            (--slen, '>') : 0;
        str = rb_str_subseq(str, 0, slen);
        rb_str_cat_cstr(str, ", ");
        rb_str_append(str, family);
        if (!rb_getnameinfo(&addr.addr, len, hbuf, sizeof(hbuf),
                            pbuf, sizeof(pbuf), NI_NUMERICHOST | NI_NUMERICSERV)) {
            rb_str_cat_cstr(str, ", ");
            rb_str_cat_cstr(str, hbuf);
            rb_str_cat_cstr(str, ", ");
            rb_str_cat_cstr(str, pbuf);
        }
        if (last) rb_str_cat(str, &last, 1);
    }
    return str;
}