Re: [boost] [config] Rethinking feature macros?

Subject: Re: [boost] [config] Rethinking feature macros?
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2017-11-06 10:40:44

On 11/06/17 04:15, Peter Dimov via Boost wrote:
> Now that there are standard feature-testing macros 
> (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0096r5.html) 
> that are being implemented by at least g++ and clang++, would it perhaps 
> make sense for us to reevaluate our decision to provide negative macros 
> in Boost.Config and start defining the standard feature macros instead 
> on the compilers that don't support them?

I think this is a bad idea. Boost.Config macros do not necessarilly 
correspond to what the compiler defines. Compilers lie sometimes by 
defining a macro while the corresponding feature is broken. Besides, I 
believe this is not Boost's prerogative to define compiler and standard 
library-specific macros.

Also, on the std-proposals list (IIRC) there was a discussion about SD-6 
macros, and there were even initiatives to entirely drop the whole idea. 
The future of SD-6 is not quite clear, IMHO. At least, library-specific 
macros have very limited use and are prime candidates for changes or 
plain removal.