[allocator.adaptor.members]

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

## 20.6 Class template scoped_allocator_adaptor [[allocator.adaptor]](allocator.adaptor#members)

### 20.6.4 Members [allocator.adaptor.members]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/memory.tex#L8873)

In the construct member functions,*OUTERMOST*(x) is*OUTERMOST*(x.outer_allocator()) if
the expression x.outer_allocator() is
valid ([[temp.deduct]](temp.deduct "13.10.3 Template argument deduction")) andx otherwise;*OUTERMOST_ALLOC_TRAITS*(x) isallocator_traits<remove_reference_t<decltype(*OUTERMOST*(x))>>[.](#1.sentence-1)

[*Note [1](#note-1)*:

*OUTERMOST*(x) and*OUTERMOST_ALLOC_TRAITS*(x) are recursive operations[.](#1.sentence-2)

It
is incumbent upon the definition of outer_allocator() to ensure that the
recursion terminates[.](#1.sentence-3)

It will terminate for all instantiations ofscoped_allocator_adaptor[.](#1.sentence-4)

— *end note*]

[🔗](#lib:inner_allocator,scoped_allocator_adaptor)

`inner_allocator_type& inner_allocator() noexcept;
const inner_allocator_type& inner_allocator() const noexcept;
`

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/memory.tex#L8897)

*Returns*: *this if sizeof...(InnerAllocs) is zero; otherwise,inner[.](#2.sentence-1)

[🔗](#lib:outer_allocator,scoped_allocator_adaptor)

`outer_allocator_type& outer_allocator() noexcept;
`

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/memory.tex#L8909)

*Returns*: static_cast<OuterAlloc&>(*this)[.](#3.sentence-1)

[🔗](#lib:outer_allocator,scoped_allocator_adaptor_)

`const outer_allocator_type& outer_allocator() const noexcept;
`

[4](#4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/memory.tex#L8920)

*Returns*: static_cast<const OuterAlloc&>(*this)[.](#4.sentence-1)

[🔗](#lib:allocate,scoped_allocator_adaptor)

`pointer allocate(size_type n);
`

[5](#5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/memory.tex#L8931)

*Returns*: allocator_traits<OuterAlloc>​::​allocate(outer_allocator(), n)[.](#5.sentence-1)

[🔗](#lib:allocate,scoped_allocator_adaptor_)

`pointer allocate(size_type n, const_void_pointer hint);
`

[6](#6)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/memory.tex#L8942)

*Returns*: allocator_traits<OuterAlloc>​::​allocate(outer_allocator(), n, hint)[.](#6.sentence-1)

[🔗](#lib:deallocate,scoped_allocator_adaptor)

`void deallocate(pointer p, size_type n) noexcept;
`

[7](#7)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/memory.tex#L8953)

*Effects*: As if by:allocator_traits<OuterAlloc>​::​deallocate(outer_allocator(), p, n);

[🔗](#lib:max_size,scoped_allocator_adaptor)

`size_type max_size() const;
`

[8](#8)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/memory.tex#L8965)

*Returns*: allocator_traits<OuterAlloc>​::​max_size(outer_allocator())[.](#8.sentence-1)

[🔗](#lib:construct,scoped_allocator_adaptor)

`template<class T, class... Args>
  void construct(T* p, Args&&... args);
`

[9](#9)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/memory.tex#L8977)

*Effects*: Equivalent to:apply([p, this](auto&&... newargs) {*OUTERMOST_ALLOC_TRAITS*(*this)::construct(*OUTERMOST*(*this), p,
 std::forward<decltype(newargs)>(newargs)...); },
 uses_allocator_construction_args<T>(inner_allocator(),
 std::forward<Args>(args)...));

[🔗](#lib:destroy,scoped_allocator_adaptor)

`template<class T>
  void destroy(T* p);
`

[10](#10)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/memory.tex#L8998)

*Effects*: Calls *OUTERMOST_ALLOC_TRAITS*(*this)​::​destroy(*OUTERMOST*(*this), p)[.](#10.sentence-1)

[🔗](#lib:select_on_container_copy_construction,scoped_allocator_adaptor)

`scoped_allocator_adaptor select_on_container_copy_construction() const;
`

[11](#11)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/memory.tex#L9009)

*Returns*: A new scoped_allocator_adaptor object
where each allocator a1 within the adaptor
is initialized withallocator_traits<A1>​::​select_on_container_copy_construction(a2),
where A1 is the type of a1 anda2 is the corresponding allocator in *this[.](#11.sentence-1)