Registers socket to receive multicast messages sent to group.
socket must be a G_SOCKET_TYPE_DATAGRAM socket, and must have
been bound to an appropriate interface and port with
g_socket_bind().
If iface is NULL, the system will automatically pick an interface
to bind to based on group.
If source_specific is TRUE, source-specific multicast as defined
in RFC 4604 is used. Note that on older platforms this may fail
with a G_IO_ERROR_NOT_SUPPORTED error.
Since 2.32
Registers socket to receive multicast messages sent to group. socket must be a G_SOCKET_TYPE_DATAGRAM socket, and must have been bound to an appropriate interface and port with g_socket_bind(). If iface is NULL, the system will automatically pick an interface to bind to based on group. If source_specific is TRUE, source-specific multicast as defined in RFC 4604 is used. Note that on older platforms this may fail with a G_IO_ERROR_NOT_SUPPORTED error. Since 2.32