Re: C++11 - friend with a template alias

From:

=?ISO-8859-1?Q?Daniel_Kr=FCgler?= <daniel.kruegler@googlemail.com>

Newsgroups:

comp.lang.c++.moderated

Date:

Mon, 7 Jul 2014 02:42:21 CST

Message-ID:

<lpb3no$eo0$1@dont-email.me>

Am 06.07.2014 11:32, schrieb Martin Bonner:

On Saturday, 5 July 2014 03:30:05 UTC+1, wojte...@googlemail.com wrote:

Hi, I want to declare alias template as a friend of class. I've tried
following constructions, that work for classes:

-- start --

#include <vector>
template <typename T>
using my_type = std::vector<T>;
class X {
     template <typename> friend my_type;
     template <typename T> friend my_type<T>;
     template <typename T> friend class my_type;
};

So you want to declare that *any* instantiation of the template
std::vector is a friend of your class? I'm not sure you can
do that.

Hmmh, you meant *every* instantiation, right?

How would you do it without the alias?

Technically, that is not that hard:

#include <vector>

class X {
  template<class, class> friend class std::vector;
};

The question is whether this would really solve the problem (see my
other response why).

HTH & Greetings from Bremen,

Daniel Kr?gler

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