The class template
allocator_traits supplies a uniform interface to all
allocator types
.An allocator cannot be a non-class type, however, even if
allocator_traits
supplies the entire required interface
.[
Note 1:
Thus, it is always possible to create
a derived class from an allocator
. —
end note]
namespace std {
template<class Alloc> struct allocator_traits {
using allocator_type = Alloc;
using value_type = typename Alloc::value_type;
using pointer = see below;
using const_pointer = see below;
using void_pointer = see below;
using const_void_pointer = see below;
using difference_type = see below;
using size_type = see below;
using propagate_on_container_copy_assignment = see below;
using propagate_on_container_move_assignment = see below;
using propagate_on_container_swap = see below;
using is_always_equal = see below;
template<class T> using rebind_alloc = see below;
template<class T> using rebind_traits = allocator_traits<rebind_alloc<T>>;
[[nodiscard]] static constexpr pointer allocate(Alloc& a, size_type n);
[[nodiscard]] static constexpr pointer allocate(Alloc& a, size_type n,
const_void_pointer hint);
static constexpr void deallocate(Alloc& a, pointer p, size_type n);
template<class T, class... Args>
static constexpr void construct(Alloc& a, T* p, Args&&... args);
template<class T>
static constexpr void destroy(Alloc& a, T* p);
static constexpr size_type max_size(const Alloc& a) noexcept;
static constexpr Alloc select_on_container_copy_construction(const Alloc& rhs);
};
}