anchor.diff:           api_b_sendto_and_recvfrom_udp4/1,
            api_b_sendto_and_recvfrom_udpL/1,
            api_b_sendmsg_and_recvmsg_udp4/1,
  +         api_b_sendmsg_and_recvmsg_udpL/1,
            api_b_send_and_recv_tcp4/1,
            api_b_send_and_recv_tcpL/1,
            api_b_sendmsg_and_recvmsg_tcp4/1,
  
positive.code: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
  %% Basically send and receive on an IPv4 UDP (dgram) socket using
  %% sendto and recvfrom..
  api_b_sendto_and_recvfrom_udpL(suite) ->
      [];
  api_b_sendto_and_recvfrom_udpL(doc) ->
  
negative.code:                           end,
                     InitState = #{domain => inet,
                                   proto  => udp,
                                   send   => Send,
                                   recv   => Recv},
                     ok = api_b_send_and_recv_udp(InitState)
             end).
  
  
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
  %% Basically send and receive on an IPv4 UDP (dgram) socket
  %% using sendmsg and recvmsg.
  api_b_sendmsg_and_recvmsg_udpL(suite) ->
      [];
  api_b_sendmsg_and_recvmsg_udpL(doc) ->
      [];
  api_b_sendmsg_and_recvmsg_udpL(_Config) when is_list(_Config) ->
      ?TT(?SECS(5)),
      tc_try(api_b_sendmsg_and_recvmsg_udpL,
             fun() -> supports_unix_domain_socket() end,
             fun() ->
                     Send = fun(Sock, Data, Dest) ->
                                    %% We need tests for this,
                                    %% but this is not the place it.
                                    %% CMsgHdr  = #{level => ip,
                                    %%              type  => tos,
                                    %%              data  => reliability},
                                    %% CMsgHdrs = [CMsgHdr],
                                    MsgHdr = #{addr => Dest,
                                               %% ctrl => CMsgHdrs,
                                               iov  => [Data]},
                                    socket:sendmsg(Sock, MsgHdr)
                            end,
                     Recv = fun(Sock) ->
                                    %% We have some issues on old darwing...
                                    %% socket:setopt(Sock, otp, debug, true),
                                    case socket:recvmsg(Sock) of
                                        {ok, #{addr  := Source,
                                               iov   := [Data]}} ->
                                            %% socket:setopt(Sock, otp, debug, false),
                                            {ok, {Source, Data}};
                                        {error, _} = ERROR ->
                                            ERROR
                                    end
                            end,
                     InitState = #{domain => local,
                                   proto  => default,
                                   send   => Send,
                                   recv   => Recv},
                     ok = api_b_send_and_recv_udp(InitState)
  