### ip::multicast::outbound_interface

Socket option for local interface to use for outgoing multicast packets.

    typedef implementation_defined outbound_interface;

Implements the IPPROTO_IP/IP_MULTICAST_IF socket option.

##### Examples

Setting the option:

    asio::ip::udp::socket socket(io_context);
    ...
    asio::ip::address_v4 local_interface =
      asio::ip::address_v4::from_string("1.2.3.4");
    asio::ip::multicast::outbound_interface option(local_interface);
    socket.set_option(option);

##### Requirements

Header: `asio/ip/multicast.hpp`

Convenience header: `asio.hpp`