Re: [boost] [config] Need help with clang config

Subject: Re: [boost] [config] Need help with clang config
From: Edward Diener (eldiener_at_[hidden])
Date: 2017-05-19 01:02:43

On 5/18/2017 5:40 PM, Peter Dimov via Boost wrote:
> John Maddock wrote:
> 
>> I've just added travis support to Boost.Config, the problem is that 
>> there are a large number of clang failures that I simply don't know 
>> how to fix, see: https://travis-ci.org/boostorg/config
>>
>> The errors occur because clang chokes on libstdc++ code, so while 
>> <regex> exists (for example), clang won't parse it.  Any ideas anyone?
> 
> The configuration with the built-in clang++ in C++11 mode should just be 
> disabled; the default libstdc++ on Travis is 4.6 and is too broken for 
> any serious C++11 work.
> 
> Clang 3.5 uses libstdc++ 4.8, for which Config probably disables <regex> 
> as known non-working, which is why it passes.
> 
> Clang 3.6 and above on that configuration use libstdc++ 4.9, which we 
> probably assume is working, but apparently not on Clang (it doesn't like 
> the constant expression 1 << 32.)
> 
> So we should disable <regex> 4.9 on Clang. This:
> 
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78905
> 
> says that _GLIBCXX_REGEX_STATE_LIMIT is defined on 5 and 
> _GLIBCXX_RELEASE is defined on 7, although I see that we have our own 
> macro BOOST_LIBSTDCXX_VERSION, so we could just use that.

I have always had a difficult problem trying to figure out with which 
version of gcc/libstdc++ a particular version of clang will work. I have 
asked about this on the clang developers mailing list but received no 
answer. If there is any information about this anywhere I would surely 
like to know where it is.