anchor.diff:  %%--------------------------------------------------------------------
   get_socket() ->
       gen_server:call(?SERVER, get_socket).
  -
  -controlling_process(Socket, Pid) ->
  -    gen_server:call(?SERVER, {controlling_process, Socket, Pid}).
   
   %%====================================================================
   %% gen_server callbacks
  
positive.code: %%--------------------------------------------------------------------
  handle_call(get_socket, _From, S) ->
      {reply, {ok, S#state.listen_socket}, S};
  handle_call({controlling_process, Socket, Pid}, _From, S) ->
      {reply, gen_tcp:controlling_process(Socket, Pid), S};
  handle_call(_Request, _From, State) ->
      Reply = ok,
      {reply, Reply, State}.
  
negative.code: -behaviour(gen_server).
  
  %% API
  -export([start_link/0, get_socket/0]).
  
  %% gen_server callbacks
  -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
  