Question

Working with C and Win32, I have a problem where my program freezes instead of closing when a quit message is posted(Alt-F4 for example), and I have to end the process with task manager.

I have this in my main loop:(problem solved)

MSG msg;
while(1)
{
    while(PeekMessage(&msg, hwnd, 0, 0, PM_REMOVE))
    {
        if(msg.message == WM_QUIT)
        {
            terminate = 1;
            while(terminate != 3) //each thread increments "terminate" by 1 before returning
            {
                Sleep(1);
            }
            return 0;
        }
        DispatchMessage(&msg);
    }
    Sleep(1);
}

It will print “OK!” in the console and then freeze.

I think this could be because I have multiple threads and they are not terminated properly (but I read that if I return from my main() function the other threads should be killed automatically). If it helps one of those threads is an OpenGL rendering thread.

Answer 1

The main function is only just a thread, you are terminating just that one. However, for a process to end, all threads need to be properly terminated or it will run forever. You’ll need to keep a reference the threads and terminate them once you receive the WM_QUIT message.