So I have a window (Windows), and my wndProc is basically the same as the one on the windows guides. However, even though WM_CLOSE gets passed (and I can use if(msg == WM_CLOSE)), I can't seem to set my shouldClose flag. I've confirmed that I still get the event within my processMessage method. SO my question is this: what is going on, and how can I make it work?

extern (Windows) LRESULT wndProc(HWND hwnd, uint msg, WPARAM wp, LPARAM lp) nothrow {
    import std.stdio;
    import std.exception;

    Win32Window* window;

    if (msg == WM_NCCREATE)
        window = setWindowPtr(hwnd, lp);
    else
        window = getWindowPtr(hwnd);

    if (window !is null)
        return window.processMessage(msg, wp, lp);
    else
        return DefWindowProc(hwnd, msg, wp, lp);
}

Window {
    //--- other stuff ---//

    LRESULT processMessage(uint msg, WPARAM wp, LPARAM lp) nothrow {
        switch (msg) {
        case WM_CLOSE:
            _shouldClose = true; //tests as true here, but has no effect after method exits
            assumeWontThrow(writeln("close request received")); //this works
            return 0;
        default:
            return DefWindowProc(_hwnd, msg, wp, lp);
        }
    }
}

Sidenote, I can't build this with ldc2 for some reason: "cannot open input file 'kernel32.lib'". dmd seems to work just fine.