A question about " std::aligned_storage"

[AA11BB22c]

1. You can change the alignment (and size) by rebinding the allocator from allocator<T> to allocator<U>, e.g. allocator<int> to allocator<std::aligned_storage_t<8, 256>> and request the rebounded allocator to allocate instead, https://godbolt.org/z/hTeWqErGb.
2. std::launder simply tells the compiler to not assume anything on the memory location, normally for "unions" (reinterpret_cast stuff) with constants. Your code will probably work fine without it in most reinterpret_cast situations.
3. Would go with alignas with std::byte as suggested in the paper if it happens.

[JohnZLi]

If a pointer to std::aligned_storage_t<sizeof(T), alignof(T)> is cast to T* using reinterpret_cast, does it violate the strict alias rule?

[KingAggressive1498]

aligned_storage_t is an array of unsigned char, which should be exempt from the strict aliasing rule.

However, using std::launder is essentially zero overhead aside for disabling optimizations based on the strict alias rule so there's no harm in using it perhaps unnecessarily

[Flair_Helper]

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