[ryao]

I had not seen the use of constexpr. You are correct that those are in C++.

[lubutu]

C23 has constexpr, albeit only for objects, not functions. The code also uses namespaces, as in `std::aligned_alloc(P, T)`.

[ryao]

You have to be 1/3 down the page to see any of this in the code examples. By that point, you would already have seen a number of examples that are valid C code and it is reasonable to expect the rest to be. At least, that was my experience.