How do I send a HANDLE type to other threads via spawn?

[Andrej Mitrovic]

Ok I did found one workaround:

HWND mainWindow = FindWindow(appName.toUTF16z, windowName.toUTF16z);

But then the work thread has to know the exact class and window name
in order to get the window handle. (HWND is a HANDLE type in
disguise).