C++ friend inheritance?

Question

Does a subclass inherit, the main class\' friend associations (both the main class\' own and other classes friended with the main class)?

Or to put it differently, h

Answer 1

You can create (static) protected methods in the parent that will allow you to do things like that.

class MyFreind
{
private:
    int m_member;
    friend class Father;
};

class Father
{
protected:
    static int& getMyFreindMember(MyFreind& io_freind) { return io_freind.m_member; }
};

class Son : public Father
{
public:
    void doSomething(MyFriend& io_freind)
    {
        int& friendMember = getMyFreindMember(io_freind);
        // ....
    } // ()
};

This however bypasses encapsulation so you probably should take a second look at your design.

Answer 2

The answer is very simple: no, subclasses do not inherit friend associations. A friend can only access the private members of the class the association is declared in, not those of parents and/or children of that class. Although you might be access protected member of a superclass, but I'm not sure about that.

Answer 3

Friendship is not inherited in C++.

The standard says (ISO/IEC 14882:2003, section 11.4.8):

Friendship is neither inherited nor transitive.

Answer 4

friend only applies to the class you explicitly make it friend and no other class.

http://www.parashift.com/c++-faq-lite/friends.html#faq-14.4