anchor.diff:  buffer_size_server(Client, IP, Port, 
   		   Socket, Cnt, [Opts|T]) when is_list(Opts) ->
       receive {Client,setopts,Cnt} -> ok end,
  -    io:format("buffer_size_server Cnt=~w setopts ~p.~n", [Cnt,Opts]),
  +    ?P("buffer_size_server Cnt=~w setopts ~p", [Cnt, Opts]),
       ok = inet:setopts(Socket, Opts),
       Client ! {self(),setopts,Cnt},
       buffer_size_server(Client, IP, Port, Socket, Cnt+1, T);
   buffer_size_server(Client, IP, Port, 
   		   Socket, Cnt, [{B,_}|T]) when is_binary(B) ->
  -    io:format(
  -      "buffer_size_server Cnt=~w expecting size ~w.~n",
  -      [Cnt,size(B)]),
  +    ?P("buffer_size_server Cnt=~w expecting size ~w", [Cnt, size(B)]),
       Client ! 
   	{self(),Cnt,
   	 case buffer_size_server_recv(Socket, IP, Port, Cnt) of
   	     D when is_binary(D) ->
   		 SizeD = byte_size(D),
  -		 io:format(
  -		   "buffer_size_server Cnt=~w received size ~w.~n",
  -		   [Cnt,SizeD]),
  +		 ?P("buffer_size_server Cnt=~w received size ~w", [Cnt, SizeD]),
   		 case B of
   		     D ->
   			 correct;
  
positive.code: 			 {unexpected,D}
  		 end;
  	     Error ->
  		 io:format(
  		   "buffer_size_server Cnt=~w received error ~w.~n",
  		   [Cnt,Error]),
  		 Error
  	 end},
      buffer_size_server(Client, IP, Port, Socket, Cnt+1, T).
  
negative.code:     ok;
  buffer_size_client(Server, IP, Port, 
  		   Socket, Cnt, [Opts|T]) when is_list(Opts) ->
      ?P("buffer_size_client Cnt=~w setopts ~p", [Cnt, Opts]),
      ok = inet:setopts(Socket, Opts),
      Server ! {self(),setopts,Cnt},
      receive {Server,setopts,Cnt} -> ok end,
      buffer_size_client(Server, IP, Port, Socket, Cnt+1, T);
  buffer_size_client(Server, IP, Port, 
  		   Socket, Cnt, [{B,Replies}|T]=Opts) when is_binary(B) ->
      ?P("buffer_size_client Cnt=~w send size ~w expecting ~p",
         [Cnt, size(B), Replies]),
      case gen_udp:send(Socket, IP, Port, <<Cnt,B/binary>>) of
  	ok ->
  	    receive
  		{Server,Cnt,Reply} ->
  		    Tag =
  			if
  			    is_tuple(Reply) ->
  				element(1, Reply);
  			    is_atom(Reply) ->
  				Reply
  			end,
  		    case lists:member(Tag, Replies) of
  			true -> ok;
  			false ->
  			    ct:fail({reply_mismatch,Cnt,Reply,Replies,
  				     byte_size(B),
  				     inet:getopts(Socket,
  						  [sndbuf,recbuf])})
  		    end,
  		    buffer_size_client(Server, IP, Port, Socket, Cnt+1, T)
  	    after 1313 ->
  		    buffer_size_client(Server, IP, Port, Socket, Cnt, Opts)
  	    end;
  	{error, Reason} ->
  	    ?P("<ERROR> Failed sending data ~w bytes of data: "
  	       "~n   SndBuf: ~p"
  	       "~n   Reason: ~p",
  	       [size(B), inet:getopts(Socket, [sndbuf]), Reason]),
  	    ct:fail(Reason)
      end.
  
  buffer_size_server(_, _, _, _, _, []) -> 
  