Circular inclusion with function inside namespace

Question

I'm starting to learn C++ and recently encountered a problem with circular dependency of two headers.
I've already tried forward declaring the Class and namespace, also played around with it in a seperate project but didn't find any solution. Whatever I do the function doesn't get access to the class private members.

Here i simplified the problem a little bit.

---

A.h

#pragma once
#include "B.h"

class Player {
private:
    int m_number;
public:
    friend void Byte::getDataChunk(Player& p);
};

---

B.h

#pragma once
#include <iostream>

#include "A.h"

class Player;

namespace Byte {
    void doOtherStuff() {
        //other Stuff
    }

    void getDataChunk(Player& p) {
        std::cout << p.m_number;
        doOtherStuff();
    }
}

---

I would really like to keep the class and namespace in seperate files, but I don't see any way of doing it.
Thanks for your help in advance!

Answer 1

You need to change A.h to include a forward declaration of getDataChunk() in namespace Byte:

#pragma once
#include "B.h"

class Player;

namespace Byte {
    void getDataChunk(Player& p);
}

class Player {
private:
    int m_number;
public:
    friend void Byte::getDataChunk(Player& p);
};

Please note also that including function definitions in header files (i.e. getDataChunk() in B.h) is going to cause you headaches.