If you want to interoperate with C and C++ and could either make people specify low-level details of the interface themselves or process C and C++ header files

If you want to interoperate with C and C++ and could either make people specify low-level details of the interface themselves or process C and C++ header files to do it automatically. Obviously the latter is a much better interoperability solution. Processing C and C++ header files means using a C/C++ compiler. It would hardly make sense to write a new one if there was a good one already available.