The code below is declared illegal by CC-4.1 whereas it is accepted by
g++-2.7.2.2. Which compiler is right ?

-- Gaby


% cat > a.C
#include <iostream.h>

class A {

    int val;

    friend class B;

public:

    class B {

    public:

        void f()
        {
            A a(10);
            cout << a.val << endl;
        }
    };

    A(int i = 0) : val(i) {}
    void g()
    {
        B b;
        b.f();
    }
};


main()
{
    A a;
    a.g();
}


% CC a.C
"a.C", line 18: Error: val is not accessible from A::B::f().
1 Error(s) detected.


--
"God never does mathematics."
 -- H. Hahn.
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>>>>> Gabriel Dos Reis <dosreis@dptmaths.ens-cachan.fr> writes:

> The code below is declared illegal by CC-4.1 whereas it is accepted by
> g++-2.7.2.2. Which compiler is right ?

CC.  This will be fixed in g++ 2.8.0.

> class A {
>     int val;
>     friend class B;

This declares that ::B is a friend of A, not A::B.  You need to say

      class B;
      friend class B;

to make A::B a friend of A.

Jason
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Gabriel Dos Reis <dosreis@dptmaths.ens-cachan.fr> writes:

>The code below is declared illegal by CC-4.1 whereas it is accepted by
>g++-2.7.2.2. Which compiler is right ?
...
>class A {
>    friend class B;

The issue here is whether this grants friendship to `::B' or to `A::B'.

I don't recall the correct answer off-hand (I think it may even
have changed at some point in the not-to-distant past).
However, I suspect that if you add a forward declaration of class B
at the appropriate scope, i.e.

 class A {
     class B;
     friend class B;

then you will have more luck.

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