[libcxx-commits] [PATCH] D110110: [libc++] [ABI BREAK] Remove non-atomic "platform" semaphore implementations.

[Arthur O'Dwyer via Phabricator via libcxx-commits]

Quuxplusone added inline comments.


================
Comment at: libcxx/docs/ReleaseNotes.rst:89
+  on all platforms, and does not use "native" semaphores such as pthreads
+  ``sem_t`` even on platforms that would support them.
+
----------------
ldionne wrote:
> 
IIUC, you want me to eliminate the diff in `ReleaseNotes.rst` from this PR, and then you'll add it manually when you cherry-pick. The diff you'll add manually will be (mildly edited-yet-again by me):
```
- The C++20 type ``std::counted_semaphore<N>`` is now based on ``std::atomic``
  on all platforms, and does not use "native" semaphores such as pthreads
  ``sem_t`` even on platforms that would support them. This changes the layout
  of ``counted_semaphore<N>``, so it is an ABI break. This change is needed to
  conform to the Standard, which requires ``counted_semaphore``'s constructor
  to be constexpr.
```


Repository:
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CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D110110/new/

https://reviews.llvm.org/D110110