Convert C++ function pointer to c function pointer

Question

I am developing a C++ application using a C library. I have to send a pointer to function to the C library.

This is my class:

 class MainWindow : pub         


        

Answer 1

@Snps answer is perfect! But as @DXM mentioned it can hold only one callback. I've improved it a little, now it can keep many callbacks of the same type. It's a little bit strange, but works perfect:

 #include 

template
struct ActualType {
    typedef T type;
};
template
struct ActualType {
    typedef typename ActualType::type type;
};

template
struct Callback;

template
struct Callback {
    typedef Ret (*ret_cb)(Params...);
    template
    static Ret callback(Args ... args) {
        func(args...);
    }

    static ret_cb getCallback(std::function fn) {
        func = fn;
        return static_cast(Callback::callback);
    }

    static std::function func;

};

template
std::function Callback::func;

#define GETCB(ptrtype,callertype) Callback::type,__COUNTER__,callertype>::getCallback

Now you can just do something like this:

typedef void (cb_type)(uint8_t, uint8_t);
class testfunc {
public:
    void test(int x) {
        std::cout << "in testfunc.test " <