When is “inline” ineffective? (in C)

Question

Some people love using inline keyword in C, and put big functions in headers. When do you consider this to be ineffective? I consider it s

Answer 1

Inline is effective in one case: when you've got a performance problem, ran your profiler with real data, and found the function call overhead for some small functions to be significant.

Outside of that, I can't imagine why you'd use it.