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03.19.2008 at 07:36AM PDT, ID: 23253729
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9.5

MFC: waiting for a thread to finish before closing another thread's dialog, in order to avoid undefined behaviour

Asked by sternocera in Windows MFC Programming, Windows Programming, Microsoft Visual C++

Hello,

I have an MFC database front end that creates a worker thread to do some database work. The worker thread maintains a pointer to the dialog, through which it manipulates various static text.

Currently, if the user closes the dialog, the new thread manipulates the now out of scope dialog, causing undefined behaviour.

I thought I'd maintain a bool which dictates if the original thread's dialog may close. In effect, the first thread's dialog waits for the second thread to finish:

void Cprocess::OnBnClickedCancel() // part of original thread
{
      Will_Cancel = true; // second thread will see this variable in it's big loop, and finish (eventually)
      while(!can_we_leave) // just before it finishes, it will once again set
//can_we_leave to true (the first thing the thread does is to set set it to false)
            Sleep(10);
      OnCancel();
}

This doesn't work, because, contrary to my expectation,  Sleep() seemingly causes all threads to sleep, not just the current one. The while loop lasts forever.

What have I done wrong? What should I do?

Regards,
SternoceraStart Free Trial
[+][-]03.19.2008 at 07:38AM PDT, ID: 21161988

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[+][-]03.19.2008 at 08:13AM PDT, ID: 21162361

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[+][-]03.19.2008 at 08:38AM PDT, ID: 21162623

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About this solution

Zones: Windows MFC Programming, Windows Programming, Microsoft Visual C++
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Solution Provided By: alb66
Participating Experts: 2
Solution Grade: A
 
 
 
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