join_multicast_group() [2/4]

void xtd::net::sockets::udp_client::join_multicast_group	(	uint32	if_index,
		const xtd::net::ip_address &	multicast_address
	)

Adds a xtd::net::sockets::udp_client to a multicast group.

Parameters

if_index	The interface index associated with the local IP address on which to join the multicast group.
multicast_address	The multicast xtd::net::ip_address of the group you want to join.

Exceptions

argument_exception	The IP address is not compatible with the xtd::net::sockets::address_family value that defines the addressing scheme of the socket.
xtd::net::sockets::socket_exception	An error occurred when attempting to access the underlying socket.
xtd::object_closed_exception	The underlying xtd::net::sockets::socket has been closed.

Remarks

The xtd::net::sockets::udp_client::join_multicast_group method subscribes the xtd::net::sockets::udp_client to a multicast group using the specified xtd::net::ip_address. After calling the xtd::net::sockets::udp_client::join_multicast_group method, the underlying xtd::net::sockets::socket sends an Internet Group Management Protocol (IGMP) packet to the router requesting membership to the multicast group. The multicast address range is 224.0.0.0 to 239.255.255.255. If you specify an address outside this range or if the router to which the request is made is not multicast enabled, xtd::net::sockets::udp_client will throw a xtd::net::sockets::socket_exception. If you receive a xtd::net::sockets::socket_exception, use xtd::net::sockets::socket_exception.ErrorCode to obtain the specific error code. Once you have obtained this code, you can refer to the Windows Sockets version 2 API error code documentation for a detailed description of the error. Once the xtd::net::sockets::udp_client is listed with the router as a member of the multicast group, it will be able to receive multicasted datagrams sent to the specified xtd::net::ip_address.

Before joining a multicast group, make sure the socket is bound to the port or endpoint. You do that by calling one of the constructors that accept a port or an endpoint as a parameter.

The if_index parameter is used to identify a hardware interface on the same link.

Note

There are several multicast address ranges to choose from. Refer to the IETF RFC 2375.

You cannot call xtd::net::sockets::udp_client::join_multicast_group on a xtd::net::sockets::udp_client constructed without a specific local port (that is, using the xtd::net::sockets::udp_client() or xtd::net::sockets::udp_client(xtd::net::sockets::address_family) constructor).

If you receive a xtd::net::sockets::socket_exception, use the xtd::net::sockets::socket_exception::error_code property to obtain the specific error code. After you have obtained this code, refer to the Windows Sockets version 2 API error code documentation in the MSDN library for a detailed description of the error.