If the type is an implicit-lifetime type, then you can legally create an unsigne... | Hacker News

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		denotational 18 days ago \| parent \| context \| favorite \| on: GCC 16 has been released If the type is an implicit-lifetime type, then you can legally create an unsigned char array, and then reinterpret_cast a pointer to that to a pointer to the type. See https://eel.is/c++draft/intro.object#def:object,implicit_cre.... https://eel.is/c++draft/intro.object#15 is an example showing this with malloc; the subsequent paragraph further permits it to work with an unsigned char array.

leni536 18 days ago [–]

1. You still need std::launder in that case.

2. It doesn't initialize the object that is implicitly created, even if the storage has initialized chars.

denotational 18 days ago | [–]

The paper that introduced the implicit lifetime mechanism suggests that std::launder is not required: https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p05....

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