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

Personally I don't think you should ever inline, unless you have first run a profiler on your code and have proven that there is a significant bottleneck on that routine that can be partially alleviated by inlining.

This is yet another case of the Premature Optimization Knuth warned about.