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Re: [SG10] Feature-testing for a TS

From: Jens Maurer <Jens.Maurer_at_[hidden]>
Date: Wed, 25 Mar 2015 23:07:27 +0100
On 03/25/2015 12:30 AM, Nelson, Clark wrote:
>> Should TSes use the macro spelling pattern
>> __cpp_experimental_whatever
>> or
>> __cpp_whatever
>> assuming that the value of the macro will change anyway when
>> a feature
>> moves from TS land to the standard proper?
> The question is, when a feature from a TS is incorporated into the standard,
> will it be changed enough to effectively make it a different feature from
> what was in the TS? If not, the same macro name should be used; if so, it
> should be a different macro name.
> Changing the macro's value is perfectly OK when only a minor tweak is made.
> Is your principal concern about the TM TS? Is there an expectation that a
> feature-test macro will be added to it before it is finalized?

Yes, there's an NB comment for it. (We made one.)

We'll go with __cpp_transactional_memory . I don't expect
large changes before going into the standard.

> All I can say about "experimental" language features is that it sure would
> be nice if we could get them right in the TS, so that, when (or if) they are
> incorporated into the standard, they don't have to be changed enough to be
> considered a different feature.

Ok. That seems to be consistent with the TM approach.


Received on 2015-03-25 23:12:41