Way to check if SWF is in fullscreen or not?

I know that SWFs embedded in HTML files cannot start in full screen mode, but if you're using a standalone player, it can. By default, I make my SWF try to go full screen when it starts, in case it's being played in a standalone player, but how would I check to see if it was successful or not? Is there a way for it to check it's full screen status?