Before c++17, if you have an allocator like Allocator<typename, size_t> you can use the rebind struct.
But now, in C++17 the rebind struct is deprecated.
What's the solution to construct an allocator<T,size_t> from an allocator<T2, size_t>?
How to avoid rebind in allocator<T, N> c++17
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2 Answers
Only std::allocator's rebind member template is deprecated. If you are using your own class, you can still define rebind.
Do it through std::allocator_traits, like:
using AllocatorForU = std::allocator_traits<AllocatorForT>::template rebind_alloc<U>;
The default for rebind_alloc for AllocatorTemplate<T, OtherTypes...> is AllocatorTemplate<U, OtherTypes...>, which works for std::allocator, which is why std::allocator<T>::rebind is deprecated. You have to define it for your class since it has a non-type template parameter.
You might use std::allocator_traits:
std::allocator_traits<Alloc>::rebind_alloc<T>
with potential typename/template.
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