unix terminal i/o

[Robert Goldman]

I am working on a program that needs to access the terminal in a pretty raw
state.  In particular, it must have some way to tell whether there are any
keys in the input buffer waiting to be read.  Is there some portable unix
call that responds with this information?  A getchar()-type function that
doesn't wait for input?  I'd appreciate any help you can give me.  

						Robert Goldman
						MultiMate International

P.S.  If you are answering from net.unix-wizards, please send answer via
mail -- I'm not wizardly enough for this newsgroup. :-(