Re: [boost] [fit] Mini Review (consider 1/2 or 1/4 weight)

Subject: Re: [boost] [fit] Mini Review (consider 1/2 or 1/4 weight)
From: Vicente J. Botet Escriba (vicente.botet_at_[hidden])
Date: 2016-03-20 17:17:21

Le 20/03/2016 21:55, Zach Laine a écrit :
> On Sun, Mar 20, 2016 at 7:53 AM, Gonzalo BG <gonzalobg88_at_[hidden]> wrote:
>
>> I want to make a minor remark about this:
>>
>>> [...]
>>>
>>> 1. Inline functions are weak symbols and don't violate ODR
>>> 2. Static variables in C++ do violate ODR (btw in C they do not) so
>>> basically you COPY every instance of the functions across compilation
>>> unit.
>>>
>>> [...]
>> FIT (and range-v3, and many other libraries) follow the best practice we
>> currently have in C++ < 17 here, which is Eric Niebler's N4381 Suggested
>> Design for Customization Points [0].
>>
>> It seems, however, that from the discussion here and in the other reviews
>> of FIT, this best practice is not "common practice" yet.
>>
>> The failure is only on us for not giving it enough exposure.
>>
>> IMO all new Boost libraries should be following N4381 as FIT does.
>>
>> On first encounter, however, a macro like BOOST_FIT_STATIC_LAMBDA
>> is going to look very suspicious: why is this required? what about ODR? ...
>>
>> Since these macros are going to remain the only viable solution for
>> a long time (until we drop support for C++<17) we should address these
>> questions on first usage in the documentation of new libraries, maybe by
>> linking against N4381 directly (which addresses the issue in great detail)
>> or by providing a small summary of N4381 in the documentation or the
>> Boost wiki.
>>
>> [0]
>>
>> http://ericniebler.github.io/std/wg21/D4381.html#no-violations-of-the-one-definition-rule
>
> +1
>
>
+1

Vicente