CODEWITHSUNDEEP
socketstcpboost-asiocancellation
Harish
Harish

Reputation: 363

boost::asio::io_service::run() is not exiting when i call boost::asio::io_serive::stop()

Hi I having written one simple application which uses the asynchronous socket functions. I am facing some problems while closing the socket.

I am using 5 second timer before calling the async_connect on the socket. In some cases the connection is not happening and timer expires. When timer is expired I am closing the socket tcp_socket.close(). But the thing is my connection callback handler is not at all called with the boost::asio::error::operation_aborted error when i tried to cancel instead of close. The same thing is happening for the next all the async connection invokes.

Eventhough I am closing the tcp socket and destroying the client_session object join() call on the created thread is not coming out means io_service::run() is still running not exiting...:-( I don't know why this is happening... tried lot of other ways still facing the same problem.

I am not getting what is the problem, all suggestions and solutions will be appreciated.

My real code some what look like this.

class client_session
{ 
   public:
   client_session(boost::asio::io_service& io_service_ )tcp_socekt_(io_service_),
                                                        timer_(io_service_)
   {
   }

   ~client_session()
   {
       tcp_socket_.close();
   }

   void OnTimerExpired(const boost::system::error_code& err)
   {
      if( err ) tcp_socket_.close();
   }

   //Its just for example this will be called from upper layer of my module. giving some information about the server.
   void connect()
   {
        //Here am starting the timer 
        timer_.expires_from_now(boost::posix_time::seconds(2));
        timer_.async_wait(boost::bind(&OutgoingSession::OnTimerExpiry, this,PLACEHLDRS::error));

        .......

        tcp_socket_.async_connect(iterator->endpoint(), boost::bind( &OutgoingSession::handle_connect, this, _1, iterator));

        ......
   }

   void OnConnect(const boost::system::error_code& err)
   {
      //Cancelling the timer 
      timer_.cancel();
      .....
      //Register for write to send the request to server
      ......
   }

   private:
   tcp::socket tcp_socket_;
   deadline_timer timer_;
} 

void main()
{
  boost::asio::io_service tcp_io_service;
  boost::asio::io_service::work tcp_work(tcp_io_service);

  boost::thread* worker = new boost::thread(&boost::asio::io_service::run,&tcp_io_service);

  client_session* csession = new client_session(tcp_io_service);
  csession->connect();

  sleep(10);

  tcp_io_service.stop();

  delete csession;

  worker.join();    //Here it not coming out of join because io_service::run() is not exited yet.
  cout<<"Termination successfull"<<endl;
}

Upvotes: 0

Views: 2099

Answers (1)

Ralf
Ralf

Reputation: 9573

There seem to be a couple of different things wrong with the posted code. I would suggest starting with smaller steps i.e. along the lines of

  • start and stop asio worker thread cleanly ( see explanation below )
  • add code to start timer: handle OnTimerExpired correctly, check error code
  • add in code for async_connect: when connect handler is called, cancel timer and check error code.
  • add in other asynchronous operations, etc.

For one, when you cancel the timer in the connect handler, the OnTimerExpired handler will be invoked with boost::asio::operation_aborted and then you close the socket, which is probably not what you want to do.

Further, you give the io_service work, yet still call stop. Generally if you give the io_service work, you want to stop the execution thread by removing the work (e.g. This can be accomplished by means of storing work in a smart pointer and resetting it) and letting the currently started asynchronous operations finish cleanly.

Upvotes: 1

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