On Thu, 29 Aug 2024 at 10:01, Jonathan Wakely <jwakely.gcc@xxxxxxxxx> wrote: > > On Thu, 29 Aug 2024 at 08:05, Georg Gast <georg-gcc@xxxxxxxxxxxxxxxx> wrote: > > > > Am Mittwoch, dem 28.08.2024 um 21:29 +0100 schrieb Jonathan Wakely: > > > It was intentional, to clean up and formalise which headers are > > > usable > > > in freestanding mode. > > > See > > > https://gcc.gnu.org/onlinedocs/libstdc++/manual/using_dynamic_or_shared.html#manual.intro.using.linkage.freestanding > > > for details on the support in GCC 13 and 14. > > > > > > However, I think we need to revisit the decision and relax some of > > > the > > > new headers so they work for freestanding again. > > > See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109814 and > > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113398 > > > Most of <chrono> is in the same category and would Just Work if we > > > removed the #error > > > > > > > > > > Hi Jonathan, > > > > thanks for the enlightment! As i read through your links i am happy > > that the newer compilers are more compliant to the standard. The past > > showed me, it's always better to stay as close to the standard as > > possible. > > I agree. However, with respect to freestanding, the standard specifies > a _minimum_ of what must be supported in freestanding environments, > and allows implementations to support more. > > What we did for GCC 13 was to reduce the set to the specified minimum, > cleaning up and simplifying how we define things for freestanding (and > making libstdc++ headers respect the -ffreestanding flag, which was > previously ignored by the library). > > Now that we have a clean baseline, I think we should incrementally add > back support for non-freestanding things that do actually work, such > as most of <chrono>. I've proposed a patch to do that now: https://gcc.gnu.org/pipermail/gcc-patches/2024-September/662921.html > > > > > > For my chrono problem, i switched to boost::chrono (header only without > > error code). This was pretty straight forward. As i already use boost > > no big hassle. > > Makes sense. > > > > > As i looked for the freestanding c++ standard i found that: > > https://en.cppreference.com/w/cpp/freestanding > > I wasn't aware about that... > > > > Now i can use my 14.2 compiler. > > > > Bye Georg > >
