Use the same 'extern "C" f()' construct as detailed in the previous question, only then proceed to actually define the function in your C++ module. The compiler will ensure that the external information sent to the linker uses C calling conventions and name mangling (ex: preceded by a single underscore). Obviously you can't make several overloaded fns simultaneously callable by a C program, since name overloading isn't supported by C.
Caveats and implementation dependencies:
* your 'main()' should be compiled with your C++ compiler.
* your C++ compiler should direct the linking process.
