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Subject: Re: [boost] C++17 detection
From: Robert Ramey (ramey_at_[hidden])
Date: 2017-09-14 14:36:42


On 9/14/17 2:27 AM, John Maddock via Boost wrote:
>
>>>> Boost.Config actually uses the feature testing macros when available
>>>> and when applicable (in combination with other things, i.e. an
>>>> understanding of what the C++ implementation in question actually is
>>>> known to support, regardless of what it advertises). Using the feature
>>>> testing macros alone may not be what you want.
>>> I'd be happy to used Boost.Config - that's where I looked first.  But I
>>> don't see what I need in there.
>>>
>> Pull requests are welcome.
>
> Indeed, or file a feature request.

Hmmm - the problem is i'm already two interrupt levels below where I
really want to be. So I was hoping for an existing fix that I didn't
really have to think about. If something that starts out seeming
trivial often end up sucking up a bunch of unanticipated time.

> Note that historically Boost.Config has never added new macros unless
> there is demand from within Boost.
>
> And while it's true that we have been laggardly in adding C++17 feature
> macros, so far no one has ever asked for them either... not once till now.
>
> BTW, what I'm missing from this discussion, is exactly what C++17
> features you are actually interested in?

BOOST_NO_CXX17_STD_IS_DETECTED

According to http://en.cppreference.com/w/cpp/experimental/is_detected

it's currently in <experimental/type_traits> as part of library
fundamentals v2. I had mistakenly thought it was slated for C++17. So
maybe it's not appropriate to include in Boost.Config yet.

Robert Ramey


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