# File lib/ipaddr.rb, line 352
  def inspect
    case @family
    when Socket::AF_INET
      af = "IPv4"
    when Socket::AF_INET6
      af = "IPv6"
    else
      raise "unsupported address family"
    end
    return sprintf("#<%s: %s:%s/%s>", self.class.name,
                   af, _to_string(@addr), _to_string(@mask_addr))
  end