[libcxx-commits] [libcxx] [libc++] Use public os_sync API instead of private __ulock on newer Apple platforms (PR #202519)

[Louis Dionne via libcxx-commits]

ldionne wrote:

Based on the discussion we had offline just now, I find this a bit pedantic and I don't clearly see how this can go wrong in practice. However, I'd be happy to reconsider if we have a bug report showing how this causes problems. @aharrison24

https://github.com/llvm/llvm-project/pull/202519