anchor.diff:  start()  -> gen_server:start({local, ?MODULE}, ?MODULE, [], []).
   stop()   -> gen_server:call(?MODULE, stop, infinity).
   init([]) -> {ok, #state{ locks = [], duration = 0 } }.
  +
  +start_internal() ->
  +    case start() of
  +        {ok,_} -> ok;
  +        {error, {already_started,_}} -> ok;
  +        Error -> Error
  +    end.
   
   %% -------------------------------------------------------------------- %%
   %%
  
positive.code: set(Option, Value)   -> call({set, Option, Value}).
  set({Option, Value}) -> call({set, Option, Value}).
  save(Filename)       -> call({save, Filename}).
  load(Filename)       -> start(), call({load, Filename}).
  
  call(Msg) -> gen_server:call(?MODULE, Msg, infinity).
  
  
negative.code: %% -------------------------------------------------------------------- %%
  
  apply(M,F,As) when is_atom(M), is_atom(F), is_list(As) ->
      ok = start_internal(),
      Opt = lcnt:rt_opt({copy_save, true}),
      lcnt:clear(),
      Res = erlang:apply(M,F,As),
  