anchor.diff:       api_to_recvmsg_tcp6
       ].
   
  -%% These cases tests what happens when the controlling process dies
  -controlling_process_cases() ->
  +%% These cases tests what happens when the socket is closed, locally or
  +%% remotely.
  +socket_closure_cases() ->
       [
  -     socket_cleanup_tcp4,
  -     socket_cleanup_tcp6,
  -     socket_cleanup_udp4,
  -     socket_cleanup_udp6,
  -
  -     socket_close_tcp4,
  -     socket_close_tcp6,
  -     socket_close_udp4,
  -     socket_close_udp6,
  -     
  -     recv_response_local_close_tcp4,
  -     recv_response_local_close_tcp6,
  -     recv_response_remote_close_tcp4,
  -     recv_response_remote_close_tcp6,
  -
  -     recvmsg_response_local_close_tcp4,
  -     recvmsg_response_local_close_tcp6,
  -     recvmsg_response_remote_close_tcp4,
  -     recvmsg_response_remote_close_tcp6,
  -
  -     acceptor_response_local_close_tcp4,
  -     acceptor_response_local_close_tcp6,
  -     acceptor_response_remote_close_tcp4,
  -     acceptor_response_remote_close_tcp6
  +     sc_socket_cleanup_tcp4,
  +     sc_socket_cleanup_tcp6,
  +     sc_socket_cleanup_udp4,
  +     sc_socket_cleanup_udp6,
  +
  +     sc_recv_response_local_close_tcp4,
  +     sc_recv_response_local_close_tcp6,
  +     sc_recv_response_remote_close_tcp4,
  +     sc_recv_response_remote_close_tcp6,
  +
  +     sc_recvmsg_response_local_close_tcp4,
  +     sc_recvmsg_response_local_close_tcp6,
  +     sc_recvmsg_response_remote_close_tcp4,
  +     sc_recvmsg_response_remote_close_tcp6,
  +
  +     sc_acceptor_response_local_close_tcp4,
  +     sc_acceptor_response_local_close_tcp6,
  +     sc_acceptor_response_remote_close_tcp4,
  +     sc_acceptor_response_remote_close_tcp6
       ].
   
   %% ticket_cases() ->
  
positive.code: %% remotely closed while the process is calling the recv function.
  %% Socket is IPv4.
  
  recv_response_remote_close_tcp4(suite) ->
      [];
  recv_response_remote_close_tcp4(doc) ->
      [];
  recv_response_remote_close_tcp4(_Config) when is_list(_Config) ->
      tc_try(recv_response_remote_close_tcp4,
             fun() ->
                     not_yet_implemented(),
                     Recv      = fun(Sock) -> socket:recv(Sock) end,
  
negative.code:            cmd  => fun(#{tester := Tester} = _State) ->
                             receive
                                 {'DOWN', _, process, Tester, Reason} ->
                                     ee("Unexpected DOWN regarding tester ~p: "
                                        "~n   ~p", [Reason]),
                                     {error, {unexpected_exit, tester}};
                                 {continue, Tester} ->
                                     ok
                             end
  