Passing member function pointer to the c-style function

Question

I am trying to pass member function pointer to the c-style function (as it\'s lib in C)

The pointer it wants is defined as:

void (*)(int, const char*         


        

Answer 1

Since the member function also has the this pointer as implied argument, it is not of the type accepted by the C function. Hence, IMHO the only way is to generate a standalone function with C linkage

class A {
public: void func(int, const char*) const;
};

extern "C" {
  void cfunc(void(*)(int, const char*));
  void call_cfunc(const A*);
}

// in some source (non-header) file:
namespace {
  const A*pa;
  void afunc(int i, const char*s)
  { pa->func(i,s); }
}

void call_cfunc(const A*a)
{
  pa = a;
  cfunc(afunc);
}