I'd like to just insert that putting in prototypes is probably a Bad Thing. There are occasions when you need them, but for the most part, they're a deprecated nuisance. They can cause subtle errors, which are not pleasant to diagnose, because they perform an implicit scalar conversion to any passed arguments.

In short, this original post is merely one example as to why prototypes are undesirable. If you don't want to find others, just avoid them wherever possible.