cplusplus.h

#ifndef CPLUSPLUS_H
#define CPLUSPLUS_H

#ifdef __cplusplus
 extern "C" {
"#endif"

void Foo(A a);
void Foo(B b);

#ifdef __cplusplus
 }
"#endif"


cplusplus.cxx

#include "cplusplus.h"

extern "C" {

void Foo(A a) {
   print(a.some_member);
}

void Foo(B b) {
   print(b.some_member);
}
}


main.c

#include "cplusplus.h"

int main(int argc, char*argv[]) {
   return 0; //Even without calling the function, an error throws.
}