anchor.diff:      ?P("try create file descriptor (fd)"),
       FD = gen_tcp_api_SUITE:getsockfd(),
       ?P("try connect to using file descriptor (~w)", [FD]),
  -    Client = case gen_tcp:connect(localhost, Port, [{fd,     FD},
  -                                                    {port,   20002},
  -                                                    {active, false}]) of
  +    Client = case gen_tcp:connect(localhost, Port, ?INET_BACKEND_OPTS(Config) ++
  +                                      [{fd,     FD},
  +                                       {port,   20002},
  +                                       {active, false}]) of
                    {ok, CSock} ->
                        CSock;
                    {error, eaddrnotavail = CReason} ->
  
positive.code: 
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
  connect_failed_str(Reason) ->
      ?F("Connect failed: ~w", [Reason]).
  
  
negative.code: t_accept_inet6_tclass(Config) when is_list(Config) ->
      TClassOpt = {tclass,8#56 bsl 2}, % Expedited forwarding
      Loopback = {0,0,0,0,0,0,0,1},
      case gen_tcp:listen(0, ?INET_BACKEND_OPTS(Config) ++ [inet6, {ip, Loopback}, TClassOpt]) of
  	{ok,L} ->
  	    LPort = ok(inet:port(L)),
  	    Sa = ok(gen_tcp:connect(Loopback, LPort, ?INET_BACKEND_OPTS(Config))),
  	    Sb = ok(gen_tcp:accept(L)),
  	    [TClassOpt] = ok(inet:getopts(Sb, [tclass])),
  	    ok = gen_tcp:close(Sb),
  