anchor.diff:      lists:foreach(Fun, sighandler_nif:module_info(exports)).
   
   %% State management
  -
   install(Sig, Fun, Ref, #state{handlers = Handlers, port = Port} = State) ->
       Installed = case sighandler_drv:status(Port, Sig) of
   		    active -> installed;
  
positive.code: -include("sighandler.hrl").
  
  %% API
  -export([start_link/0, stop/0, install/2, remove/1, remove/2, lookup_term/1]).
  
  %% gen_server callbacks
  -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
  
negative.code:     gen_server:start_link({local, ?SERVER}, ?MODULE, [], []).
  
  stop() -> gen_server:call(?SERVER, stop).
  
  registered()-> 
      State=gen_server:call(?SERVER,registered),
      State#state.handlers.
  
  %%%===================================================================
  %%% gen_server callbacks
  