Re: [boost] Will addressof be in C++0x?

From: Howard Hinnant (hinnant_at_[hidden])
Date: 2007-10-13 10:08:22

On Oct 12, 2007, at 2:27 PM, Andrey Semashev wrote:

> Hi,
>
> I'm not sure I'm asking this question in the right list, so sorry if
> I've misplaced my post.
>
> I'd like to ask if boost::addressof is going to be proposed to be
> included in the upcoming C++ Standard. And what is more important to  
> me,
> will it solve the problem of storing objects with custom operator& in
> STL containers and acquiring their addresses with
> std::allocator<T>::address. I'm sure such discussion must have went in
> the Committee or in this list, I've found some traces of it in the  
> GMANE
> archive but I couldn't find any conclusion.

As of last week, it looks like std::allocator<T>::address will supply  
the functionality of boost::addressof.  This is LWG issue 634:

http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#634

The latest WP:

http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2369.pdf

is currently lacking the restriction C++03 has concerning  
container::value_type's with overloaded operator&.  That being said,  
the requirements on the value_type in the containers is still a topic  
under debate, so the current state of the WP should not be taken as  
the last word.

I'm afraid my answer amounts to: we're seriously considering it;  
maybe. :-\

Perhaps I should turn this around and ask you a question:  What  
motivating use cases (of yours) can I bring to the committee to affirm  
our current position that value_type's with overloaded operator& can  
be put into the standard containers?

-Howard