C And C++ Coding Standards

Question

What are best practices with regards to C and C++ coding standards? Should developers be allowed to willy-nilly mix them together. Are there any complications when linking

Answer 1

The biggest issue is calling a C function from C++ code or vice versa. In that case, you want to make sure you mark the function as having "C" linkage using extern "C". You can do this in the header file directly using:

#if defined( __cplusplus )
extern "C" {
#endif

extern int myfunc( const char *param, int another_one );

#if defined( __cplusplus )
}
#endif

You need the #ifs because C code that includes it won't understand extern "C".

If you don't want to (or can't) change the header file, you can do it in the C++ code:

extern "C" {
#include "myfuncheader.h"
}

You can mark a C++ function as having C linkage the same way, and then you can call it from C code. You can't do this for overloaded functions or C++ classes.

Other than that, there should be no problem mixing C and C++. We have a number of decades-old C functions that are still being used by our C++ code.