[petters]

Going from 220 to 450 ms would be a disaster in my project. It has many thousands of files. Recompilation of almost everything happens from time to time.

If those made-up numbers were true, they would be very significant and an argument in favor of keeping the code in C

[levodelellis]

A 200ms difference is adding or removing 200lines lines of implementation, and spliting it up into a file can make it slower because of include overhead. You completely made up C being twice as fast as C++.