Landing: 0cb732698c1c
Project / Subsystem
gcc / libstdc++
Date
2026-07-31
Author
Patrick Palka
Commit
0cb732698c1cf5b5d7c4e2da64ad506e55fae551
Source
github
Perf win
No
Breaking
No
All attributes
- project
- gcc
- subsystem
- libstdc++
- patch_id
- —
- commit_hash
- 0cb732698c1cf5b5d7c4e2da64ad506e55fae551
- source_type
- github
- headline
- Libstdc++: Add LWG 4440 feature-test macros to <iosfwd>.
- tldr
- Adds C++20 feature-test macros for spanstream and syncbuf to libstdc++'s <iosfwd>.
- author
- Patrick Palka
- outcome
- committed
- performance_win
- false
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • libstdc++
- • c++20
- • feature-test macro
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-07-31T00:00:00.000Z
This commit adds C++20 feature-test macros __cpp_lib_spanstream and __cpp_lib_syncbuf to the <iosfwd> header in libstdc++. These macros indicate the availability of the std::spanstream and std::syncbuf features, respectively, as defined by the C++ standard. The macros are verified in the test suite.