Re: [boost] Clang 600 and BOOST_SYSTEM_CONSTEXPR causes error_code.hpp compile failure.

Subject: Re: [boost] Clang 600 and BOOST_SYSTEM_CONSTEXPR causes error_code.hpp compile failure.
From: James E. King III (jking_at_[hidden])
Date: 2018-07-09 15:58:17

On Sun, Jul 8, 2018 at 12:54 PM Peter Dimov via Boost <boost_at_[hidden]>
wrote:

> John Maddock wrote:
> > I preprocessed the source and it's picking up the latest headers for me:
> >
> m:\\compilers\\vc2017\\vc\\tools\\msvc\\14.13.26128\\include\\system_error
> >
> > and I still see:
> >
> > class error_category
> >      {    // categorize an error
> > public:
> >      /* constexpr */ error_category() _NOEXCEPT    // TRANSITION
>
> I have 14.14.26428 and I see the same. :-/
>
> Well this sure simplifies version checking for this particular issue if
> nothing else.
>
> > Defines wise we have:
> ...
> >     _CPPLIB_VER                             =650
>
> After looking at the config_info output from the test matrix, the values
> are, for reference:
>
> _CPPLIB_VER=405: msvc-8.0
> _CPPLIB_VER=505: msvc-9.0
> _CPPLIB_VER=520: msvc-10.0
> _CPPLIB_VER=540: msvc-11.0
> _CPPLIB_VER=610: msvc-12.0
> _CPPLIB_VER=650: msvc-14.0 and above
>
> The new macros are:
>
> "The STL now identifies itself with two macros, defined by including any
> STL
> header (e.g. <ciso646>). _MSVC_STL_VERSION is defined as 141 and will
> remain
> that way for the VS 2017 v141 toolset series. _MSVC_STL_UPDATE is defined
> as
> 201709 in VS 2017 15.5, and will be increased as features are added in
> future updates. (The year-month typically won’t correspond to an update’s
> release date. Our process for updating this macro is “we’re checking in
> std::meow() and it’s now October, so we need to change the value”, and
> depending on branch/merge timing, it might take a month or more to ship.)
> The value for VS 2017 15.6 is not yet set in stone, but it will be 201711
> or
> greater."
>
>
> https://blogs.msdn.microsoft.com/vcblog/2017/12/19/c17-progress-in-vs-2017-15-5-and-15-6/
>
> and I was going to suggest we add them, but someone already did:
>
>
> https://github.com/boostorg/config/commit/d5986d697ca534e18d192bd28b8c1177fe220157
>
> Incidentally... while looking into this, I encountered
>
>
> https://github.com/boostorg/config/commit/15a0c119a13938bd00b99273e6fb876ff019c688
>
> which uses the compiler version to decide on a library feature. It will
> define BOOST_NO_CXX17_STD_APPLY under Clang.
>
> It might be a good idea to codify the above knowledge somehow into a
> BOOST_MSSTL_VERSION macro and then check that instead of _MSC_VER or
> BOOST_MSVC which generally doesn't work with Clang.
>
>
>
It sounds like Boost.Predef could help here, since it can detect Dinkumware?

- Jim