Does extern “C” have any effect in C?

Question

I just got some C code that uses extern \"C\" to declare external functions like this:

extern \"C\" void func();

Is this valid C? I\'m getting

Answer 1

this is a C++ notation to tell the compiler/linker to use C calling standards.

Usually that line is wrapped in an pre-processor statement.

#ifdef __cplusplus
extern "C" {
#endif

// stuff

#ifdef __cplusplus
}
#endif