On Mon, Jul 27, 2020 at 02:31:38PM -0400, Zack Weinberg wrote: > URL: > <https://savannah.gnu.org/support/?110286> > > Summary: Make it possible to request a specific (non-latest) > version of a language standard > Project: Autoconf > Submitted by: zackw > Submitted on: Mon 27 Jul 2020 06:31:37 PM UTC > Category: None > Priority: 5 - Normal > Severity: 1 - Wish > Status: None > Privacy: Public > Assigned to: None > Originator Email: > Open/Closed: Open > Discussion Lock: Any > Operating System: None > > _______________________________________________________ > > Details: > > Feedback on the 2.69b beta indicates that users find the new behavior of > AC_PROG_CC and AC_PROG_CXX, automatically selecting the latest supported > language standard, problematic. Quoting > https://lists.gnu.org/archive/html/autoconf/2020-07/msg00010.html : > > > One issue we [PostgreSQL] would like to point out is that > > the new scheme of automatically checking for the latest > > version of the C and C++ standards (deprecating AC_PROG_CC_C99 > > etc.) is problematic... > > > > [W]e have set C99 as the project standard. So checking for > > C11 is (a) useless, and (b) bad because we don't want > > developers to accidentally make use of C11 features and have > > the compiler accept them silently. > > > > It looks like it's not easy to disable these tests even > > with low-level hackery. It would be better if there were > > still a way to set the preferred level of C and C++ in > > an official way. > > and https://lists.gnu.org/archive/html/autoconf/2020-07/msg00012.html : > > > Particularly as applies to C++, it is useful to be able > > to set an upper bar (and lower bar) for the C++ version > > requested because C++11 is in many ways not similar to > > older C++. I am already aware that some of my own software > > will not compile with C++11 because of removed deprecated > > features which I have not attended to yet in the code. > > Furthermore, the ABI often changes between C++ versions > > and it is useful to be able to specify the C++ version > > for purposes of the ABI.
In regard of C++, we (in SageMath, https://sagemath.org) are using AX_CXX_COMPILE_STDCXX from https://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx.html to do version detection of C++. Perhaps it can be promoted to the core AC_ macros. Just in case, Dmitrii > > _______________________________________________________ > > Reply to this item at: > > <https://savannah.gnu.org/support/?110286> > > _______________________________________________ > Message sent via Savannah > https://savannah.gnu.org/ > >
signature.asc
Description: PGP signature
