anchor.diff:  
   %% @type percept_option() = procs | ports | exclusive
   
  --type(percept_option() :: 'procs' | 'ports' | 'exclusive' | 'scheduler').
  +-type percept_option() :: 'procs' | 'ports' | 'exclusive' | 'scheduler'.
   
   %%==========================================================================
   %%
  
positive.code: 	    });
  	_ -> 
  	    parse_profile_options(Opts, {TOpts, POpts})
  
      end.
  
negative.code:     receive {Tracer, ok} -> ok end,
      erlang:trace(Tracee, false, [procs]),
      ok.
  
  %% @spec stop() -> ok | {'error', 'not_started'}
  %% @doc Stops profiling.
      
  -spec stop() -> 'ok' | {'error', 'not_started'}.
  
  stop() ->
      erlang:system_profile(undefined, [runnable_ports, runnable_procs]),
  