How to Get Focus Window handle?

[yulincat]

I found it isn't supported AttachThreadInput on Windows Mobile, so I can only get owner current thread's focus window handle.
How to get other process/thread's focus window handle?

[radhoo]

It would be fair enough to assume that the window-on-top has the keyboard focus. For this assumption, the solution is simple: GetForegroundWindow.

For the general solution I will try to prepare an article, as it requires more then a couple of lines of code, as it needs to interact with other processes memory space.