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instance method

IPAddr#multicast?

multicast?

# File tmp/rubies/ruby-4.1.0-preview1/lib/ipaddr.rb, line 357
def multicast?
  case @family
  when Socket::AF_INET
    (@addr & 0xf0000000 == 0xe0000000) && prefix >= 4 # 224.0.0.0/4
  when Socket::AF_INET6
    (@addr & 0xff00_0000_0000_0000_0000_0000_0000_0000 == 0xff00_0000_0000_0000_0000_0000_0000_0000) && prefix >= 8 || # ff00::/8
      (@addr >> 32 == 0xffff &&
        (@addr & 0xf0000000 == 0xe0000000) && prefix >= 100 # ::ffff:224.0.0.0/100 (224.0.0.0/4)
      )
  else
    raise AddressFamilyError, "unsupported address family"
  end
end

Returns true if the ipaddr is a multicast address. IPv4 addresses in 224.0.0.0/4 and IPv6 multicast addresses in ff00::/8 are considered multicast. Multicast IPv4 addresses in the IPv4-mapped IPv6 address range are also considered multicast.