When should we use asserts in C?

Question

I am writing a function in C. As a matter of style, when is it good to use assert compared to returning an error code. Lets say the function is dividing two numbers. Should

Answer 1

The conventional wisdom is to use assert() to help debug your code, to warn you when something "impossible", something that must not happen, has happened. This "warning" takes the form of exiting your program.

I've heard Jim Coplien (general C++ guru and SCRUM trainer) advocate leaving your asserts active in deployed code. (It sounds crazy, I know...) This was specifically for high-reliability server code. The motivation was that it's better to fail, hard, and let another node take over, than to tolerate your server being in an "impossible" state.

(And of course, track the failures, and analyze them. It means there is a bug or incorrect assumption.)