[boost] Re: [math constants] C++ Language gurus views needed and Codewarrior & Comeau testers

From: David Abrahams (dave_at_[hidden])
Date: 2004-03-01 16:43:19

Phil Richards <news_at_[hidden]> writes:

> On Mon, 01 Mar 2004 18:09:20 +0000, Paul A Bristow wrote:
> [Daniel Frey said:]
>> | I really suggest you look at my code at
>> | <http://groups.yahoo.com/group/boost/files/MathConstants/>, which solves
>> | all of the above points.
>> Except that VC 7.1 doesn't think it is legal C++ :-((
>> I think we need to establish if it is correct (as gcc and Intel think it
>> is)
>
> Nope, as has been said a number of times, it is not valid C++.  typeof is
> not in the existing C++ standard.  It is a very useful extension
> implemented by a number of vendors, but that doesn't make it standard.
>
>> Or to find some workaround that VC 7.1 will accept.
>
> Indeed.
>
>> It would be helpful to know what do other highly conformant compilers,
>> like CodeWarrior and Comeau, say about Daniel Frey's proposal?
>
> Well, you still have to get over the boost Guidelines saying:
>  Aim for ISO Standard C++. Than means making effective use of the standard
>  features of the language, and avoiding non-standard compiler extensions.
>  It also means using the C++ Standard Library where applicable.
>
> It doesn't forbid using extensions, but I seem to remember David Abrahams
> being a little more assertive about not using non-standard extensions :-)

To be precise, code should usually not *rely* on non-standard
extensions.  It's fine to use non-standard extensions if they can
make the library perform better, use less code, etc., but there
should be a fallback position for compilers that don't support the
extension.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com