Kenny Stuart wrote:
> template<typename _T> class A{ friend _T; };
> template<typename _T> class A2{ typedef typename _T::P T; friend T; };

Neither of these are legal. A friend class declaration must include
the class-key, according to 11.4/2. But then 3.4.4 and 7.1.5.3 forbid
the class-name from being a typedef name or template parameter. The
upshot is that there is no way in Standard C++ to grant friendship to
a class except by naming it explicitly in the friend declaration.

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Hi all,

 Can someone answer a question regarding the C++ standard and tell me if the
following non-elaborated friend declaration is legal, I can't find a section
in the standard that explicitly allows or disallows this
([14.5.3/temp.friend], [11.4/class.friend]), it works on most compilers but
g++ (GCC) 3.2 disallows it with the message 'template parameters cannot be
friends', the second example however works fine with g++.

template<typename _T>
class A{
 friend _T;
};

class B{};
typedef A<B> C;

------------------------------------------------------

template<typename _T>
class A2{
 typedef typename _T::its_still_me_but_not_as_a_template_parameter  T;
 friend T;
};

class B2{ typedef B2 its_still_me_but_not_as_a_template_parameter; };
typedef A<B2> C2;


thanks.

Kenny Stuart.



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