boost::asio checker

[MixedCoder]

try
      {
        boost::asio::io_service io_service;
    
        tcp::acceptor acceptor(io_service, tcp::endpoint(tcp::v4(), 13));
    
        for (;;)
        {
          tcp::socket socket(io_service);
          acceptor.accept(socket);
         //how do i make a checker here if the client is not sending anything then server send or if the client sending then server recive 
        }
      }
      catch (std::exception& e)
      {
        std::cerr << e.what() << std::endl;
      }

how do i make a checker , if the client is not sending anything then server send or if the client sending then server recive