IPv4 multicast supports the following socket options for the Macro, Callable, and REXX Sockets APIs:
Use the C, Macro, Callable, or REXX Sockets API SETSOCKOPT call to set these options. Use the C, Macro, Callable or REXX Sockets API GETSOCKOPT call to get the current settings. The status of the IP_ADD_MEMBERSHIP, IP_DROP_MEMBERSHIP, IP_ADD_SOURCE_MEMBERSHIP, IP_DROP_SOURCE_MEMBERSHIP, IP_BLOCK_SOURCE, and IP_UNBLOCK_SOURCE options are exceptions, because they are SETSOCKOPT options only.