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

Subject: Re: [boost] [config] Rethinking feature macros?
From: Peter Dimov (lists_at_[hidden])
Date: 2017-11-06 02:21:07

Edward Diener wrote:

> I brought up SD-6 for Boost Config some time ago, but the original 
> objection was that a great deal of the standard c++ header files would 
> have to be included by Boost Config to use most of SD-6.

Config already uses the SD-6 macros when possible, but what I'm suggesting 
is for it not to use it, but to define it when the implementation does not 
support them, so that libraries can use them.

For correct use, the library would need to include both the standard header 
defining the __cpp_lib_... macro and boost/config.hpp, as the macro could be 
defined by either.

This is admittedly a bit more fragile than the present arrangement. Compiler 
macros don't need a header to be included though, so for them, just 
boost/config.hpp would be needed.