Re: [boost] c++11 and gcc 4.7

Subject: Re: [boost] c++11 and gcc 4.7
From: Vicente J. Botet Escriba (vicente.botet_at_[hidden])
Date: 2011-12-06 17:15:10

Le 06/12/11 20:08, Bruce Adams a écrit :
>
> Hi,
>      I am attempting to do a cost benefit analysis to justify adopting the subset of C++11 that is supported by gcc 4.7.
> I believe there is a strong case for doing so from just the minor features and library improvements. However, I am
> having a hard time putting together a convincing cost benefit analysis (actually I would like to be able to do this
> with parts of boost too - any help with this would be great).
>
>
> The status of boost for gcc4.7 is unclear (I know it has not been officially released yet but the status for gcc 4.6.2 is
> also unclear).
AFAIK, 4.6.2 was released.
>
>
>
> Will boost.thread work as a drop in replacement for std::thread or is anything missing or broken on the
> core language side? (On the gcc side I am also interested in whether std::thread is a sufficiently complete implementation
> of the standard that boost.thread might not be necessary).
Not now. Boost.Thread was developed in parallel to the Thread standard 
definition, but there are a lot of missing features and differences in 
the syntax. If you have to work only with gcc I belive you should use 
the c++11 library version.
>
> The answer to this question may make my work harder.
>
> I was asked to justifiy either TR1, some part of boost or C++11 as my preference. I opted for C++11 as the most useful.
> I would probably have to justify boost libraries on a case by case basis.
>
> Justifying use of C++11 actually amounts to justifying a compiler upgrade + possibly training + possibly boost.thread
>
> As threads are one of the biggest features of c++11, I may be asked to justify just boost.thread vs
>
> gcc 4.7 + boost.thread.
Just move to gcc 4.7.
>
>
> Surprisingly another thing that is unclear is the exact set of boost libraries that were included in C++11.
Most of the ones appering in Boost.TR1 + Thread + Chrono
>
> I don't have either the standard (other than the February draft http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3242.pdf)
> or a good summary of the standard to hand.
This is a quite good approximation.
>
> Suprisingly neither the boost website nor the g++ page have a list either,
> though the following two links are helpful:
>
>
> http://www.boost.org/doc/libs/1_48_0/?view=filtered_std-tr1
>
> http://www.boost.org/doc/libs/1_48_0/?view=filtered_std-proposal
>
> I found a reference somewhere online (that I can no longer find) claiming, I believe incorrectly,
>
> that boost file_system is in C++11.
No. FileSystem will be surely proposed to the standard committee soon.
>
> But nor its is presence in the 2005 "TR2" proposal. I worry that the 2005 TR2 proposal may
> be confused with any real TR2 proposal following on from C++11.
Proposal are just proposal ;-)
>
> I note that boost.chrono claims to be implemnting C++11 but I would have thought it was
> other way around and that the boost library was incorporated into the standard.
No. Boost.Chrono was based on the standard draft proposal of Howard Hinnant.

Best,
Vicente