Even OS X's C++ usage is kind of a historical oddity. OPENSTEP drivers were written in ObjC for an API called DriverKit, but OS X/Darwin/xnu replaced that with

Even OS X's C++ usage is kind of a historical oddity. OPENSTEP drivers were written in ObjC for an API called DriverKit, but OS X/Darwin/xnu replaced that with the C++ IOKit. The rest of the kernel is still C. I wrote a comment a few years ago explaining why I think that decision was made: https://news.ycombinator.com/item?id=10006411 https://news.ycombinator.com/item?id=10006411