static constexpr std::size_t required_alignment= /*implementation-defined*/;
The value of
required_alignment is the required alignment for an object to be referenced by an atomic reference, which is at least alignof(T).
Hardware could require that an object to be referenced by an
atomic_ref<T> have stricter alignment than other
T objects, and whether operations on an
atomic_ref are lock-free can depend on the alignment of the referenced object.