Re: [boost] Are some of the trunk regression tests running in C++0x mode when they shouldn't be?

Subject: Re: [boost] Are some of the trunk regression tests running in C++0x mode when they shouldn't be?
From: Dave Abrahams (dave_at_[hidden])
Date: 2011-11-10 19:17:38

on Thu Nov 10 2011, Christopher Jefferson <chris-AT-bubblescope.net> wrote:

> On 10 Nov 2011, at 23:30, Gennadiy Rozental wrote:
>
>> Vicente J. Botet Escriba <vicente.botet <at> wanadoo.fr> writes:
>> 
>>> 
>>> Le 10/11/11 21:13, Gennadiy Rozental a écrit :
>>>> Steven Watanabe<watanabesj<at>  gmail.com>  writes:
>>>>>> Looks like -std=c++0x is being specified when it shouldn't for some reason?
>>>>>> Is something broken, or am i imagining it?
>>>>>> 
>>>>> This is a problem in Boost.Test as of r75372.
>>>> How should I specify in Jamfile that I want to require c++11 support from gcc
>>>> starting with version a.b.c?
>>>> 
>>> You should not require this. Even if using a given version of gcc, users 
>>> could been to preserve a C++03 behavior.
>> 
>> What is the problem with enabling C++11 features if possible? We do not expect
>> backward compatibility issues, don't we?
>> 
>> What about MSVC? It has C++11 enabled by default. 
>> 
>> Some of the new features of Boost.Test require c++11 support. I want to be able
>> to test it and I want users to be able to use it.
>
> There are two problems with enabling C++11 unconditionally in gcc:
>
> 1) It breaks binary compatability of some stl containers
> 2) Different versions of gcc support different amounts of C++11. In
> particular, there are at least 2 (maybe 3?) different semantics for
> rvalue references floating around. In general, I would advise only
> trying to use boost in C++11 mode in g++ 4.5 at least. I don't think
> it's worth the effort to make boost work with each of the early
> partial implementations floating around in the various compilers.

3) The committee made some breaking changes to the language (not many,
   but still)...

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com