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Re: MT app hangs [message #24022 is a reply to message #24014]

Thu, 17 December 2009 18:20

mirek
Messages: 13980
Registered: November 2005

Ultimate Member

mdelfede wrote on Thu, 17 December 2009 07:51

Hi, Mirek, thank for your answer Smile

Anyways, I don't see a simple solution to my problem, indeed.
As far as I can understand, I can't use Wait() from inside the button callback, or anyways can't wait for the thread to stop from inside a gui event handler, as the thread could try a GuiLock between the Wait() call and its termination.

Ha! That is true.

Well, that is the hard part of MT...

I guess the really bad issue here is the Wait call. I thing things would be much simplified if you avoided Wait and posted callback at the end of thread.

Quote:

Why does Gui need to be locked inside event handlers ?

Because it does a lot of things to GUI status. E.g. setting focuses, changing widget status etc...

In theory, the locking could be much fine-grained (like locking individual widgets before accessing them). But doubt it would be any easier....

Quote:

Or there's a nicer solution ?

void TestThread::thrCb(void)
{
	{
		GuiLock __;
		status.Set("Running, " + FormatInt(thr.GetCount()) + " threads");
	}
	for(;;)
	{
		{
			GuiLock __;
			if(progress < 100)
				progress++;
			else
				progress = 0;
			if(stop)
				break;
		}
		Sleep(1000);
	}
	{
		GuiLock __;
		status.Set("Idle....");
	}
	PostCallback(THISBACK(Stop));
}

void TestThread::Stop()
{
	button.SetLabel("START");
}


void TestThread::buttonCb(void)
{
	if(stop)
	{
		stop = false;
		button.SetLabel("STOP");
		thr.Run(THISBACK(thrCb));
	}
	else
		stop = true;
}

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