[cfe-dev] [libcxx] RFC: C++14 and beyond

Howard Hinnant hhinnant at apple.com
Tue May 7 10:53:15 PDT 2013

On May 2, 2013, at 1:51 PM, Marshall Clow <mclow.lists at gmail.com> wrote:

> How do you detect that a compilation was invoked with the "std=c++1y" flag?
> The traditional way of doing that is by inspecting the preprocessor define __cplusplus, but the value for that has not been determined for C++14.
> tot clang and gcc 4.8 both use "201103" for -std=c++11 and -std=c++1y
> [ I expect this will change by the time C++14 is adopted, but that's what it is today. ]

***** clang Feature Request ******

This is a problem.  At the moment, there is *no* difference in *any* compiler-supplied macro between -std=c++11 and -std=c++1y.  We don't have to use __cplusplus to key on, but it would be nice to somehow detect the difference between -std=c++11 and -std=c++1y.

On May 2, 2013, at 2:29 PM, Jonathan Sauer <jonathan.sauer at gmx.de> wrote:

> As far as clang is concerned this could be handled by __has_feature, e.g. __has_feature(cpp1y).
> (or some other identifier that doesn't have the "ell" vs "one" disambiguation problem.)

Which would be fine.  But if it is there on tot today, I don't know how to spell it.

***** clang Feature Request ******


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