[libcxx-commits] [libcxx] [libcxx] Implementation of P1831R1 (PR #101439)

[Mark de Wever via libcxx-commits]

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@@ -131,6 +154,11 @@ struct __atomic_base // false
   __atomic_base(const __atomic_base&) = delete;
 };
 
+#if _LIBCPP_STD_VER >= 20
+#  undef _LIBCPP_REQUIRE_IS_ALWAYS_LOCK_FREE
+#  define _LIBCPP_REQUIRE_IS_ALWAYS_LOCK_FREE requires __base::is_always_lock_free
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mordante wrote:

I really dislike this, it makes it very hard to determine what the macro `_LIBCPP_REQUIRE_IS_ALWAYS_LOCK_FREE` is defined to. 

In the `__config` header we have some macros to conditionally do things, for example `__NOEXCEPT_(...)`. There is no `_LIBCPP_REQUIRES(...)` since there was no need for that macro. Can you add that macro for this patch?

https://github.com/llvm/llvm-project/pull/101439