Windows 7: how to bring a window to the front no matter what other window has focus?

I’m implementing a task-bar replacement, dock-like application-switcher style program. It’s doing some unique stuff with OpenGL, and with keyboard shortcuts, so the way it’s set up, the window doesn’t always have focus. I’d like to implement it such that I can bring an arbitrary window to the foreground, much like a taskbar or an ALT-TAB program would.

How to safely write to a file?

Imagine you have a library for working with some sort of XML file or configuration file. The library reads the whole file into memory and provides methods for editing the content. When you are done manipulating the content you can call a write to save the content back to file. The question is how to do this in a safe way.