https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108235
--- Comment #12 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jonathan Wakely <r...@gcc.gnu.org>: https://gcc.gnu.org/g:61da01772a3dff61cf23ba2ffba33bccb68d1063 commit r13-5052-g61da01772a3dff61cf23ba2ffba33bccb68d1063 Author: Jonathan Wakely <jwak...@redhat.com> Date: Fri Jan 6 18:39:14 2023 +0000 libstdc++: Refactor time_zone::_Impl::rules_counter [PR108235] Abstract the atomic counter used to synchronize access to time_zone infos behind a Lockable class API, and use atomic_signed_lock_free instead of atomic<int_least32_t>, as that should be the most efficient type. (For futex-supporting targets it makes no difference, but might benefit other targets in future.) The new API allows the calling code to be simpler, without needing to repeat the same error prone preprocessor conditions in multiple places. It also allows using template metaprogramming to decide whether to use the atomic or a mutex, which gives us more flexibility than only using preprocessor conditions. That allows us to choose the mutex implementation for targets such as hppa-hp-hpux11.11 where 32-bit atomics are not lock-free and so would introduce an unwanted dependency on libatomic. libstdc++-v3/ChangeLog: PR libstdc++/108235 * src/c++20/tzdb.cc (time_zone::_Impl::RulesCounter): New class template and partial specialization for synchronizing access to time_zone::_Impl::infos. (time_zone::_M_get_sys_info, reload_tzdb): Adjust uses of rules_counter.
