anchor.diff:      ?line ok;
   buffer_size_client(Server, IP, Port, 
   		   Socket, Cnt, [Opts|T]) when is_list(Opts) ->
  +    ?line io:format("buffer_size_client Cnt=~w setopts ~p.~n", [Cnt,Opts]),
       ?line ok = inet:setopts(Socket, Opts),
       ?line Server ! {self(),setopts,Cnt},
       ?line receive {Server,setopts,Cnt} -> ok end,
       ?line buffer_size_client(Server, IP, Port, Socket, Cnt+1, T);
   buffer_size_client(Server, IP, Port, 
  -		   Socket, Cnt, [{B,Replies}|T]) when is_binary(B) ->
  -    ?line ok = gen_udp:send(Socket, IP, Port, B),
  +		   Socket, Cnt, [{B,Replies}|T]=Opts) when is_binary(B) ->
  +    ?line io:format(
  +	    "buffer_size_client Cnt=~w send size ~w expecting ~p.~n",
  +	    [Cnt,size(B),Replies]),
  +    ?line ok = gen_udp:send(Socket, IP, Port, <<Cnt,B/binary>>),
       ?line receive
   	      {Server,Cnt,Reply} ->
  -		  ?line case lists:member(Reply, Replies) of
  +		  ?line Tag =
  +		      if
  +			  is_tuple(Reply) ->
  +			      element(1, Reply);
  +			  is_atom(Reply) ->
  +			      Reply
  +		      end,
  +		  ?line case lists:member(Tag, Replies) of
   			    true -> ok;
   			    false ->
   				?line 
  
positive.code: 					     byte_size(B),
  					     inet:getopts(Socket,
  							  [sndbuf,recbuf])})
  			end
  	  end,
      ?line buffer_size_client(Server, IP, Port, Socket, Cnt+1, T).
  
  buffer_size_server(_, _, _, _, _, []) -> 
      ok;
  buffer_size_server(Client, IP, Port, 
  		   Socket, Cnt, [Opts|T]) when is_list(Opts) ->
      receive {Client,setopts,Cnt} -> ok end,
      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) ->
      Client ! 
  	{self(),Cnt,
  	 receive
  	     {udp,Socket,IP,Port,D} when is_binary(D) ->
  		 SizeD = byte_size(D),
  		 case B of
  		     D ->                             correct;
  		     <<D:SizeD/binary,_/binary>> ->   truncated
  		 end;
  	     {udp_error,Socket,Error} ->              Error
  	 after 5000 ->                                timeout
  	 end},
      buffer_size_server(Client, IP, Port, Socket, Cnt+1, T).
  
  
  
  
negative.code:     ?line Bin = list_to_binary(lists:seq(0, Len-1)),
      ?line M = 8192 div Len,
      ?line Spec0 =
  	[{opt,M},{safe,M-3},{long,M+1},
  	 {opt,2*M},{safe,2*M-3},{long,2*M+1},
  	 {opt,4*M},{safe,4*M-3},{long,4*M+1}],
      ?line Spec =
  	[case Tag of
  	     opt ->
  