[libcxx-commits] [libcxx] [libc++] Deprecated `shared_ptr` Atomic Access APIs as per P0718R2 & Implemented P2869R3: Remove Deprecated `shared_ptr` Atomic Access APIs from C++26 (PR #87111)

[Nico Weber via libcxx-commits]

nico wrote:

We're trying to use the replacement over in https://github.com/google/perfetto/issues/785 .  https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2023/p2869r2.pdf suggests to use `std::atomic<std::shared_ptr<...>>`. But we're getting errors that `_Atomic cannot be applied to type 'std::shared_ptry<X>' which is not trivially copiable`.

Maybe we're holding something wrong, but https://libcxx.llvm.org/FeatureTestMacroTable.html says "__cpp_lib_atomic_shared_ptr unimplemented". Which suggests that the recommended replacement doesn't work in ilbc++ yet.

Is that correct?

If so, I'll suggest that adding this deprecation is premature.

https://github.com/llvm/llvm-project/pull/87111