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Re: [patch] Default to --enable-libstdcxx-time=auto
- From: Daniel Krügler <daniel dot kruegler at gmail dot com>
- To: Jakub Jelinek <jakub at redhat dot com>
- Cc: Rainer Orth <ro at cebitec dot uni-bielefeld dot de>, Jonathan Wakely <jwakely dot gcc at gmail dot com>, Benjamin Kosnik <bkoz at redhat dot com>, Paolo Carlini <paolo dot carlini at oracle dot com>, "libstdc++" <libstdc++ at gcc dot gnu dot org>, gcc-patches <gcc-patches at gcc dot gnu dot org>
- Date: Fri, 24 May 2013 10:54:18 +0200
- Subject: Re: [patch] Default to --enable-libstdcxx-time=auto
- References: <20130523102827 dot GV1377 at tucnak dot redhat dot com> <CAH6eHdStnqrmWiWBioQLe53VCjMN-AC_56RW+Xnm=z0=pEDtxQ at mail dot gmail dot com> <20130523140218 dot GW1377 at tucnak dot redhat dot com> <20130523162611 dot GA1377 at tucnak dot redhat dot com> <yddbo81whlf dot fsf at CeBiTec dot Uni-Bielefeld dot DE> <20130523205022 dot GF1377 at tucnak dot redhat dot com> <ydd7gipwh3a dot fsf at CeBiTec dot Uni-Bielefeld dot DE> <20130523210611 dot GH1377 at tucnak dot redhat dot com> <ydd38tdwgis dot fsf at CeBiTec dot Uni-Bielefeld dot DE> <yddy5b5uzuq dot fsf at CeBiTec dot Uni-Bielefeld dot DE> <20130524075705 dot GK1377 at tucnak dot redhat dot com>
2013/5/24 Jakub Jelinek <jakub@redhat.com>:
> So, let's talk about other options, is constexpr/const on
> std::chrono::steady_clock::is_steady
> required by the standard (as in, could we export
> _ZNSt6chrono12steady_clock9is_steadyE@@GLIBCXX_3.4.19
> and let the library say which case it is, it would be constexpr when
> we know for sure, and a static variable otherwise)?
> But looking at C++11 draft, in [time.clock.steady]
> it even says that is_steady is true (then we are violating the standard
> even when we represent steady_clock as typedef system_clock steady_clock;).
Yes, steady_clock::is_steady needs to be true and to be usable within
constant expressions.
- Daniel