anchor.diff:          true  -> start_file(system, File);
           false -> start(system, ?MODULE, File)
       end.
  -    
  +
   %% @doc Starts a logging handler registered with 'Id', that outputs to File.
   %% @end
   start_file(Id, File) ->
  
positive.code:             end
      end.
  
  %% @doc Writes to the logging handler Scope, formatting Fmt with Args. This
  %% should work in much the same way as io:format/2 does, although this is
  %% implementation dependent to some extent.
  
negative.code: log(Scope, Fmt, Args) ->
      %% NB: we avoid gen_event:call/3 because it requires {Module, Id} to be
      %% maintained *somewhere* in order to identify a recipient, which is about
      %% as useful as a chocolate teapot here. Instead we match on id in
      %% the handle_event callback and filter out unwanted messages that way.
      gen_event:sync_notify(systest_event_log, {Scope, Fmt, Args}).
  
  