How to make a template class friend of another class.

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4 total messages Started by Wiljo Thu, 24 Feb 2005 09:24

#39

Author: Wiljo
Date: Thu, 24 Feb 2005 09:24

35 lines
1697 bytes

Hi all,

I have a class with protected and/or private members that need to be accessed by 
a close relative but template class. Normally one would make the second class 
friend of the first, but when this second class is a template, how can I 
accomplish it then?

//#
//# class A
//#
class A
{
public:

friend class B;		//* This wont work, because class B is template

private:
	void privateFunction();
};
//#
//# template class B
//#
template <class XType>
class B
{
public:
	void myFunction( A *ptrA )
	{ ptrA->privateFunction(); }
};
//#
//#

Any ideas would be greatly appreciated.

Wiljo.

Re: How to make a template class friend of another class.

#40

Author: Thomas Maeder [TeamB]
Date: Thu, 24 Feb 2005 17:52

37 lines
1939 bytes

Wiljo <invalid@invalid.address> writes:

> I have a class with protected and/or private members that need to be
> accessed by a close relative but template class. Normally one would
> make the second class friend of the first, but when this second class
> is a template, how can I accomplish it then?

Do you want all specializations of B to be friends of A, or just one
particular specialization?


> //#
> //# class A
> //#
> class A
> {
> public:
>
> friend class B;		//* This wont work, because class B is template
>
> private:
> 	void privateFunction();
> };
> //#
> //# template class B
> //#
> template <class XType>
> class B
> {
> public:
> 	void myFunction( A *ptrA )
> 	{ ptrA->privateFunction(); }
> };
> //#
> //#

What's the point in making B a template?

Re: How to make a template class friend of another class.

#43

Author: Wiljo
Date: Mon, 07 Mar 2005 10:51

22 lines
1965 bytes

Thomas Maeder [TeamB] wrote:

> Do you want all specializations of B to be friends of A, or just one
> particular specialization?
> 
Yes, I want all specializations of B to be friend of A.
> 
> What's the point in making B a template?

Well I oversimplified the example code a bit too much, and I didn't make sense 
anymore. B needs to be template, because it handles several different object 
types. The one thing they have in common is that they are all derived from class 
A. A has private functionality, that I don't wan't to access directly from any 
derived class, hence the private specifier. I DO wan't to access these private 
functionality from the template class though. Hence my question.

I solved the problem by making a base class for the template class B. This base 
class can be friend of A without any problem.

Thanks anyway.

Wiljo.

Re: How to make a template class friend of another class.

#44

Author: Thomas Maeder [TeamB]
Date: Mon, 07 Mar 2005 16:35

5 lines
1354 bytes

Wiljo <invalid@invalid.address> writes:

This is the wrong newsgroup for this topic.

Cf. my answer over in .cppbuilder.language

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