Objective-C, .m / .mm performance difference?

Question

I tend to use the .mm extension by default when creating new classes so that I can use ObjC++ later on if I require it.

Is there any disadvantage to doing this? When

Answer 1

If you only use C features, .mm files should generate code that performs very similar to .m

There is also no downside to renaming a file from .m to .mm later when you desire C++ features