I'm probably missing something here, but when you are setting up your signal handler, you'll certainly have the opportunity to save aside whatever existing handler is in place already?
Yes - and if there is no other way around it, I'll do that.
My concern would be whether the stuff you're using that set their own handler would be as accomodating to your handler, and whether you would ever end up in a loop situation.
That's exactly the reason I was originally reluctant to simply check for existing handlers - "What if something else clobbers mine?" I will just have to try it and find out...