Landing: b12fdd952511
Project / Subsystem
gcc / gcc/libstdc++
Date
2026-06-22
Author
Jonathan Wakely
Commit
b12fdd952511786bf8d285e7080e94deeb32aa1d
Source
github
Perf win
No
Breaking
No
All attributes
- project
- gcc
- subsystem
- gcc/libstdc++
- patch_id
- —
- commit_hash
- b12fdd952511786bf8d285e7080e94deeb32aa1d
- source_type
- github
- headline
- Remove std::atomic dependency in tzdb.cc for non-atomic targets
- tldr
- Libstdc++ tzdb.cc avoids atomic<unsigned> for targets lacking atomic word operations.
- author
- Jonathan Wakely
- outcome
- committed
- performance_win
- false
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • libstdc++
- • portability
- • atomic
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-06-22T00:00:00.000Z
To support targets without atomic word operations, such as Cortex-M0, libstdc++‘s timezone database implementation (tzdb.cc) now avoids a hard dependency on std::atomic<unsigned>. This change replaces the atomic variable with a struct that uses a mutex-protected access or std::atomic_ref, depending on the context, ensuring compatibility across a wider range of hardware.