friendship getting inherited ?? strange

Question

As it is said - "friends are not inherited" .
it means that

class c
 {public:
 friend void i_am_friend();
 };

class d:public c
{public:
 //
};

here void i_am_friend() is not inherited in class d .In more technical terms(i think this way.)

Object of class d will not have memory allocated for void i_am_friend() as it is friend of base class .
Now consider question no. 14.3 at this page http://www.parashift.com/c++-faq/friends.html

class Base {
 public:
   friend void f(Base& b);
   ...
 protected:
   virtual void do_f();
   ...
 };

 inline void f(Base& b)
 {
   b.do_f();
 }

 class Derived : public Base {
 public:
   ...
 protected:
   virtual void do_f();  // "Override" the behavior of f(Base& b)
   ...
 };

 void userCode(Base& b)
 {
   f(b);
 }

How can this code be correct?? because

class derived d;// d will not have friend function
class base *b=&d; //as a result b also don't have member function

So call to f(b) should be error here.

So what is correct to say :-
friendship isn't inherited
or friendship is inherited but can't be used in derived class

score 2 · Answer 1 · answered May 18 '12 at 04:49

friendship isn't inherited

This is true, even in your example. The call to f(b) should NOT be an error there, because the Derived object is converted into Base& type.

The function f can access only the private and protected parts of the Base class, but only public parts of the Derived class.

friendship getting inherited ?? strange

1 Answers1