[Patch] Implement Option 3 of DR 431

[Howard Hinnant]

On Dec 20, 2005, at 3:47 PM, Paolo Carlini wrote:

> Howard Hinnant wrote:
>> Caution for mainline:  C++03 allocators are not required to be  
>> swappable (they have copyconstructible but lack copyassignable).   
>> In practice this doesn't appear to be a major problem, and can be  
>> easily fixed by adding a swap to your non-assignable allocator.   
>> Just thought I'd better mention it.
> I know about that, of course, and we already discussed the issue a  
> bit. Given that otherwise container::swap is totally broken for  
> unequal allocators, and your analysis in N1599, it's the best we  
> can do... well you agree of course ;) and Gaby too. Maybe,  
> additionally to mentioning DR 431 in the docs, as we usually do by  
> default for implemented DRs, we can also add a note to the 4.2  
> release notes, but we have got time for that. If nobody objects,  
> I'm definitely going to commit this work to mainline too.
>
> Paolo.

No objection here.