How does extern "C" work in C++?

Tuesday, September 3, 2019

I see some code in C++ using extern "C" at the beginning of the file like this:

#ifdef __cplusplus 
extern "C" {} 
#endif

What does this mean? How does it work?

Answer

It's probably not like that, but more like:

#ifdef __cplusplus 
extern "C" {
#endif

//some includes or declarations

#ifdef __cplusplus 
}
#endif

It tells the compiler to use C name mangling for whatever is declared inside the directives.

The way you have it now:

#ifdef __cplusplus 
extern "C" {} 
#endif

is just dead code.

Blog