How to determine that a screensaver is running?

Question

One solution that one could suggest is to periodically look for a special \'Screen-saver\' desktop, and if it\'s present then count it as a running screensaver.

But

Answer 1

I think the key is to identify the screensaver by its window class ("WindowsScreenSaverClass"). I found this page How do I start, detect and stop screen savers? that has some code examples and explanations.