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Re: Adding a socket to a GUI application [message #50333 is a reply to message #48134]

Wed, 26 September 2018 18:51

Giorgio
Messages: 218
Registered: August 2015

Experienced Member

Hi there,
I put this question aside for a while, few days ago I resumed it.

I had a look to threads and tcpsocket as suggested. For a starter I decided to focus on thread. So, I forked before the .Run() and put in the thread the code to manage the socket. I ended up with this:

void tagidSocket()
{
	//Socket
	RLOG("Socket's thread started");
	for(;;) {
		if(Thread::IsShutdownThreads())
			return;
		RLOG("I'm still alive");
		Sleep(1000);
	}
}

GUI_APP_MAIN{
	//Reading a .ini file, connection to a db
	[...]

	Thread t;
	t.Run(callback(tagidSocket));
	app.Run();
    
	RLOG("Exiting, terminating socket");
	Thread::ShutdownThreads();
}

This works as expected: I can use my application normally, I can see in the log the sentence "I'm still alive" several times, and when I close the applications it exits nicely / does not hung up.

After that I put the socket management in the equation and here came the problems. I began using the very same code used in the example "SocketServer". I copied everything in my tagidSocket() function. This is the result (GUI_APP_MAIN does not change):

void tagidSocket()
{
	TcpSocket server;
	if(!server.Listen(23456, 5)) {
		RLOG("Unable to initialize server socket");
		return;
	}
	RLOG("Socket started, waiting for requests...");
	for(;;) {
		if(Thread::IsShutdownThreads())
			return;
		TcpSocket s;
		if(s.Accept(server)) {
			String w = s.GetLine();
			//Cout() << "Request: " << w << " from: " << s.GetPeerAddr() << '\n';
			RLOG("Request: " + w + " from: " + s.GetPeerAddr() + '\n');
			if(w == "time")
				s.Put(AsString(GetSysTime()));
			else
				s.Put(AsString(3 * atoi(~w)));
			s.Put("\n");
			
		}
	}
}

With this change, when I launch my application everything is ok, I can connect to the socket and exchange data, but when I close my application it hangs and I have to kill it manually.

I try to debug the problem and I found out that the code responsible for the problem is the following: if(s.Accept(server)) { [...] }.

If I comment out everything in the if above (and also the if itself), the application can be closed normally (but of course a socket without the "listening" part makes no sense).

Why is this happening?

Regards,
gio

[Updated on: Wed, 26 September 2018 18:53]

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