C++ by-reference argument and C linkage

Question

I have encountered a working (with XLC8 and MSFT9 compilers) piece of code, containing a C++ file with a function defined with C linkage and a reference argument. This bugs

Answer 1

In many cases, but not all, a reference can be implemented with an 'auto-dereferenced' pointer. That any particular compiler treats a function with C linkage and a reference parameter this way is not guaranteed in the C++ standard, and you should treat it as an implementation detail.

It isn't hard to write a forwarding function that takes a pointer and calls your function, if you need to do this without relying on implementation details:

void real_f(int& n) {
  n++;
}
extern "C" void f(int* p) { // called from C code
  real_f(*p);
}