Friend declarations: nested classes and base-clauses

[Quentin026]

Hi there!

I've got two questions about friend declarations.

1)

According to the 11.8.1 paragraph of C++03 standard:

The members of a nested class have no special access to members of an enclosing class, nor to classes or functions that have granted friendship to an enclosing class

How is it possible that a single function can grant friendship to a class ?

2)

My second question concerns a base-clause of a nested class.

We can read in C++0x standard draft (11.4.2 paragraph) that:

Declaring a class to be a friend implies that the names of private and protected members from the class granting friendship can be accessed in the base-specifiers and member declarations of the befriended class.
[ Example:

class A
{
    class B { };
    friend class X;
};

struct X : A::B //OK: A::B accessible to friend
{
    A::B mx; //OK: A::B accessible to member of friend
    class Y
    {
        A::B my; //OK: A::B accessible to nested member of friend
    };
};

—end example ]

It isn't mentioned in the example whether private and protected type names from the class granting friendship can be used in the base-clause of a nested class of the friend class (here it would be the base-clause of class Y).

I think they can, do you think so too ?

I can't check it by myself since I don't have any compatible with C++0x compilers...

[D_Drmmr]

It isn't mentioned in the example whether private and protected type names from the class granting friendship can be used in the base-clause of a nested class of the friend class (here it would be the base-clause of class Y).

What's base-clause? Did you mean base class?
That would mean that the compilation of the base class of Y would be dependent on its derived class, since if Y derives from it, it would also be a friend of X, but if Y doesn't derive from it, it wouldn't be a friend of X. That's not possible.

[Quentin026]

No, I didn't mean base class :P

base-clause = base-specifier = base-specifier-list

It's a place where we specify base classes which we want derived from.

Simply put:

class A : public BASE_CLASS_1, public BASE_CLASS_2    //<---- base-clause
{
    //...
};