What happens if during a signal handling in UNIX, the same signal gets sent to the program?

Any ideas on this? Is there some kind of a signal queue, or does it get dropped?

While we are at this question, is it true that signal handlers should do as minimal work as possible?

I read somewhere that a signal handler should use a pipe and just write one byte to it, indicating what the program should do. Then somewhere else the program periodically checks the pipe, and dispatches based on byte in it. (I might have misunderstood it)

Thanks, Boda Cydo.