Question

I have issue with thread-safe callbacks.

void draw_something() { /* draws something */ }

And the question is, how to call draw_something in main application thread every specify amount of time irrespective of other code(so it would act like C# Timer and fire function in main thread)? Earlier I was using CreateWindow to create(in main thread) auxiliary window which handles messages from SendMessage(which was sent from another timer-thread):

void MainThreadFunction(){
    CreateThread(0, NULL, GoProc, NULL, NULL, NULL);
}

DWORD WINAPI GoProc(LPVOID lpParam){
    while(1){
        SendMessage(auxiliary_window_hWnd, ADDINATIONAL_MESSAGE, 0, 0);
        Sleep(30);
    }
    return 0;
}

So window’s MessageQueue deals safethread calls, but I don’t think if it’s very efficient and elegant way to do it. I know there is better way(maybe boost?) but I don’t know it.

Answer 1

You can use the Windows SetTimer call to get a periodic WM_TIMER message and skip the second thread altogether.