Using Doxygen with C, do you comment the function prototype or the definition? Or both?

Question

I\'m using Doxygen with some embedded C source. Given a .c/.h file pair, do you put Doxygen comments on the function prototype (.h file) or the function definition (.c file)

Answer 1

We comment only the function definitions, but we use it with C++.
Write it at both places is wasting time. About the warning, if your documentation looks good, maybe it's a good way to ignore such warnings.