[default.allocator.general]

# 20 Memory management library [[mem]](./#mem)

## 20.2 Memory [[memory]](memory#default.allocator.general)

### 20.2.10 The default allocator [[default.allocator]](default.allocator#general)

#### 20.2.10.1 General [default.allocator.general]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/memory.tex#L1956)

All specializations of the default allocator meet the
allocator completeness requirements ([[allocator.requirements.completeness]](allocator.requirements.completeness "16.4.4.6.2 Allocator completeness requirements"))[.](#1.sentence-1)

[🔗](#lib:allocator)

namespace std {template<class T> class allocator {public:using value_type = T; using size_type = size_t; using difference_type = ptrdiff_t; using propagate_on_container_move_assignment = true_type; constexpr allocator() noexcept; constexpr allocator(const allocator&) noexcept; template<class U> constexpr allocator(const allocator<U>&) noexcept; constexpr ~allocator(); constexpr allocator& operator=(const allocator&) = default; constexpr T* allocate(size_t n); constexpr allocation_result<T*> allocate_at_least(size_t n); constexpr void deallocate(T* p, size_t n); };}

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/memory.tex#L1988)

allocator_traits<allocator<T>>​::​is_always_equal​::​value is true for any T[.](#2.sentence-1)