Re: [Boost.Config] Detect compiler support for std::current_exception

From: dariomt_at_[hidden]
Date: 2019-06-03 16:30:19

>
> >>> Hi all,
>> >>>
>> >>> I'm working on a Boost.Exception issue [1]  and I need to detect
>> compiler
>> >>> support of std::current_exception. In the issue there is a suggestion
>> to
>> >>> use #if __cplusplus > 199711L but that does not work for my use case
>> >>> (VS2015 reports __cplusplus = 199711L).
>> >>
>> >> MSVC defines _MSVC_LANG for this[1]. At least, it used to. However, it
>> >> would be cleaner to have a dedicated macro in Boost.Config for this.
>> >>
>> > Totally agree.
>> >
>> >>
>> >>> Is it possible to add a config macro for this?
>> >>> Or is there a good enough existing macro I can use?
>> >>
>> >> I don't think there is. Something like BOOST_NO_CXX11_HDR_EXCEPTION
>> >> would be useful.
>> >
>> > I would need to detect support for std::current_exception, not the
>> presence
>> > of header <exception>, so I would think that
>> > BOOST_NO_CXX11_CURRENT_EXCEPTION is what I need, right?
>>
>> BOOST_NO_CXX11_HDR_EXCEPTION, as all BOOST_NO_CXX11_HDR_* macros, detect
>> that the header not only exists, but is usable and contains all major
>> components described by the standard. In case of
>> BOOST_NO_CXX11_HDR_EXCEPTION, that would mean std::exception_ptr,
>> std::current_exception, std::rethrow_exception, std::make_exception_ptr,
>> etc. You need at least std::exception_ptr and std::current_exception.
>>
>
> Thanks, that makes sense!
>
>
>> > Should I open an issue in github for Boost.Config?
>>
>> Yes, or better yet - make a PR.
>>
>
> Added github Issue #284 [1], I'll try to come up with a PR.
>
> Wondering how deep the rabbit hole goes...  ^_^
> Regards
>
> [1] https://github.com/boostorg/config/issues/284
>

Hi all,

I've added these files to my local boost/config repo, following the example
set by other tests:
       test/boost_no_cxx11_hdr_exception.ipp
       test/no_cxx11_hdr_exception_fail.cpp
       test/no_cxx11_hdr_exception_pass.cpp

Now I can see a lot of automatically generated files with no instructions
to generate them! Are there instructions for developers that I've missed?

I've tried several things, and luckily this seems to do something:
cd path/to/libs/config/tools
..\..\..\b2.exe toolset=msvc-14.0

and indeed I can see many files being changed, although most of them only
the timestamp: "This file was automatically generated on..."

Sorry if this is a stupid question, but, am I going in the right direction?
Also, I was planning for a minimal PR, but I see dozens of files changed...
How do I know which files I should commit and which are only noise?
And last: should I ask these questions here or in the github issue?

Thanks!